ORCID Profile
0000-0002-8036-5864
Current Organisation
UNSW Sydney
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Public Health and Health Services | Health and Community Services | Health, Clinical and Counselling Psychology | Psychology | Social and Community Psychology
Ethnicity, Multiculturalism and Migrant Development and Welfare | Specific Population Health (excl. Indigenous Health) not elsewhere classified | Families and Family Services |
Publisher: Springer Science and Business Media LLC
Date: 20-05-2012
Abstract: Quantum dots have been used in biomedical research for imaging, diagnostics and sensing purposes. However, concerns over the cytotoxicity of their heavy metal constituents and conflicting results from in vitro and small animal toxicity studies have limited their translation towards clinical applications. Here, we show in a pilot study that rhesus macaques injected with phospholipid micelle-encapsulated CdSe/CdS/ZnS quantum dots do not exhibit evidence of toxicity. Blood and biochemical markers remained within normal ranges following treatment, and histology of major organs after 90 days showed no abnormalities. Our results show that acute toxicity of these quantum dots in vivo can be minimal. However, chemical analysis revealed that most of the initial dose of cadmium remained in the liver, spleen and kidneys after 90 days. This means that the breakdown and clearance of quantum dots is quite slow, suggesting that longer-term studies will be required to determine the ultimate fate of these heavy metals and the impact of their persistence in primates.
Publisher: American Chemical Society (ACS)
Date: 18-05-2011
DOI: 10.1021/BC100552P
Abstract: Conventional quantum dots have great potential in cancer-related imaging and diagnostic applications however, these applications are limited by concerns about the inherent toxicity of their core materials (e.g., cadmium, lead). Virtually all imaging applications require conjugation of the imaging agent to a biologically active molecule to achieve selective uptake or binding. Here, we report a study of biocompatible silicon quantum dots covalently attached to biomolecules including lysine, folate, antimesothelin, and transferrin. The particles possess desirable physical properties, surface chemistry, and optical properties. Folate- and antimesothelin-conjugated silicon quantum dots show selective uptake into Panc-1 cells. This study contributes to the preclinical evaluation of silicon quantum dots and further demonstrates their potential as an imaging agent for cancer applications.
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/C0CC00667J
Abstract: Cyclic RGD-peptide functionalized phospholipids micelle-encapsulated near-infrared CdTe/ZnSe quantum dots were synthesized as multifunctional probes for targeting and imaging tumors in live animals.
Publisher: Elsevier BV
Date: 12-2007
Publisher: Oxford University Press (OUP)
Date: 10-07-2021
DOI: 10.1093/SCAN/NSAB077
Abstract: Social attachment systems are disrupted for refugees through trauma and forced displacement. This study tested how the attachment system mitigates neural responses to threat in refugees with posttraumatic stress disorder (PTSD). Refugees with PTSD (N = 28) and refugee trauma-exposed controls (N = 22) viewed threat-related stimuli primed by attachment cues during a functional magnetic resonance imaging scan. Group differences and the moderating effects of avoidant or anxious attachment style and grief related to separation from family on brain activity and connectivity patterns were examined. Separation grief was associated with increased amygdala but decreased ventromedial prefrontal cortical (VMPFC) activity to the attachment prime and decreased VMPFC and hippoc al activity to attachment primed threat in the PTSD (vs trauma-exposed control) group. Avoidant attachment style was connected with increased dorsal frontoparietal attention regional activity to attachment prime cues in the PTSD group. Anxious attachment style was associated with reduced left amygdala connectivity with left medial prefrontal regions to attachment primed threat in the PTSD group. Separation grief appears to reduce attachment buffering of threat reactivity in refugees with PTSD, while avoidant and anxious attachment style modulated attentional and prefrontal regulatory mechanisms in PTSD, respectively. Considering social attachments in refugees could be important to post-trauma recovery, based within changes in key emotion regulation brain systems.
Publisher: Cambridge University Press (CUP)
Date: 12-2006
Publisher: Public Library of Science (PLoS)
Date: 13-08-2015
Publisher: World Scientific Pub Co Pte Lt
Date: 03-2007
DOI: 10.1142/S0219635207001398
Abstract: Following an integrative neuroscience perspective, we propose that cognitive and emotional functions are integrally linked, and that genetic polymorphisms which impact upon neural processes may have complementary effects on these functions. The brain-derived neurotrophic factor (BDNF) 66Met allele may contribute to both cognitive and emotional aspects of the depression phenotype. In 374 nonclinical subjects, BDNF genotype differences in task-related ERPs, emotion, memory, and EEG cortical arousal were examined. Using path modeling, higher negative affect in Met homozygotes was predicted by slow-wave EEG via the mediating effects of neuroticism. Both negative affect and working memory deficits were predicted by disturbances in emotion- and cognitive-related ERPs. This model held across groups with varying levels of depressed mood. Since impairments in emotion and working memory are core features of major depression, the BDNF Met allele may contribute to vulnerability for this disorder. An integrative approach in which genotypes are considered in combination with brain function and behavioral measures may be important in identifying profile markers of depression. This study directly demonstrates that cognitive and emotional neural networks are not parallel independent systems, but rather highly integrated with effects on both cognitive performance and emotional behavior.
Publisher: SAGE Publications
Date: 29-05-2023
DOI: 10.1177/00048674231177950
Abstract: In response to growing numbers of refugees worldwide, host governments are increasingly implementing temporary protection policies however, little is known regarding the mental health impact of these policies. This online longitudinal study investigated whether refugees who transitioned from low visa security (e.g. short-term transient visas) to medium (e.g. temporary protection visas) or high visa (e.g. permanent visas) security showed changes in depression symptoms, social difficulties and immigration-related fears. Participants were 1,201 refugees and asylum-seekers from Arabic, Farsi, Tamil or English-speaking backgrounds. Study variables were measured prior to and after change in visa status (6 months apart). Refugees who transitioned from low to medium security visas showed reduced immigration-related fear ( B = −0.09, 95% confidence interval = −0.29 to −0.06), but no change in depression symptoms or social difficulties compared to those who retained low visa security. Refugees who transitioned from low to high security visas showed reduced depression symptoms ( B = −0.02, 95% confidence interval = −0.04 to −0.01), social difficulties ( B = −0.04, 95% confidence interval = −0.05 to −0.01) and immigration-related fear ( B = −0.03, 95% confidence interval = −0.06 to −0.01) compared to those who retained low visa security. Findings indicate that the increased security afforded by temporary protection policies (vs short-term transient visas) did not translate into improved mental health and social outcomes for refugees. In contrast, permanent protection was associated with significant improvements in psychological and social functioning. These results have important policy implications for countries who have committed to protect and facilitate improved mental health among refugees.
Publisher: Cambridge University Press (CUP)
Date: 30-08-2016
DOI: 10.1017/S2045796016000317
Abstract: Grief symptoms and a sense of injustice may be interrelated responses amongst persons exposed to mass conflict and both reactions may contribute to post-traumatic stress disorder (PTSD) symptoms. As yet, however, there is a dearth of data examining these relationships. Our study examined the contributions of grief and a sense of injustice to a model of PTSD symptoms that included the established determinants of trauma events, ongoing adversity and severe psychological distress. The study involved a large population s le ( n = 2964, response rate: 82.4%) surveyed in post-conflict Timor-Leste. The survey sites included an urban administrative area (suco) in Dili, the capital of Timor-Leste and a rural village located an hour's drive away. Culturally adapted measures were applied to assess conflict related traumatic events (TEs), ongoing adversity, persisting preoccupations with injustice, symptoms of grief, psychological distress (including depressive symptoms) and PTSD symptoms. We tested a series of structural equation models, the final comprehensive model, which included indices of grief symptoms and injustice, producing a good fit. Locating grief symptoms as the endpoint of the model produced a non-converging model. In the final model, strong associations were evident between grief and injustice ( β = 0.34, s.e. = 0.02, p 0.01) and grief and PTSD symptoms ( β = 0.14, s.e. = 0.02, p 0.01). The sense of injustice exerted a considerable effect on PTSD symptoms ( β = 0.13, s.e. = 0.03, p 0.01). In addition, multiple indirect paths were evident, most involving grief and a sense of injustice, attesting to the complex inter-relationship of these factors in contributing to PTSD symptoms. Our findings support an expanded model of PTSD symptoms relevant to post-conflict populations, in which grief symptoms and a sense of injustice play pivotal roles. The model supports the importance of a focus on loss, grief and a sense of injustice in conducting trauma-focused psychotherapies for PTSD amongst populations exposed to mass conflict and violence. Further research is needed to identify the precise mechanisms whereby grief symptoms and the sense of injustice impact on PTSD symptoms.
Publisher: Optica Publishing Group
Date: 07-10-2009
DOI: 10.1364/OE.17.019041
Publisher: Elsevier BV
Date: 10-2011
Publisher: Springer Science and Business Media LLC
Date: 10-05-2016
Publisher: Oxford University Press (OUP)
Date: 03-2018
DOI: 10.1093/IJRL/EEY017
Publisher: Springer Science and Business Media LLC
Date: 06-06-2012
Abstract: In this paper, we report on the enhancement of spectral photoresponsivity of porous silicon metal–semiconductor metal (PS-MSM) photodetector embedded with colloidal quantum dots (QDs) inside the pore layer. The detection efficiency of QDs/PS hybrid-MSM photodetector was enhanced by five times larger than that of the undoped PS-MSM photodetector. The bandgap alignment between PS (approximately 1.77 eV) and QDs (approximately 1.91 eV) facilitates the photoinduced electron transfer from QDs to PS whereby enhancing the photoresponsivity. We also showed that the photoresponsitivity of QD/PS hybrid-MSM photodetector depends on the number of layer coatings of QDs and the pore sizes of PS.
Publisher: Elsevier
Date: 2012
Publisher: Informa UK Limited
Date: 2021
Publisher: Wiley
Date: 29-06-2022
Publisher: Elsevier BV
Date: 09-2013
DOI: 10.1016/J.JAD.2013.06.006
Abstract: There is growing research interest in understanding and analyzing explosive forms of anger. General epidemiological studies have focused on the DSM-IV category of Intermittent Explosive Disorder (IED), while refugee and post-conflict research have used culturally-based indices of explosive anger. The aim of this study was to test the convergence of a culturally-sensitive community measure of explosive anger with a structured clinical interview diagnosis of IED in Timor-Leste, a country with a history of significant mass violence and displacement. A double-blind clinical concordance study was conducted amongst a stratified community s le in post-conflict Timor-Leste (n=85) to compare a community measure of anger against the Structured Clinical Interview (SCID) module for IED. Clinical concordance between the two measures was high: the area under the curve (AUC) index was 0.90 (95% CI: 0.83-0.98) sensitivity and specificity were 93.3% and 87.5% respectively. Response rates were modest due to the participant's time commitments. It is possible to achieve convergence between culturally-sensitive measures of explosive anger and the DSM-IV construct of IED, allowing comparison of findings across settings and populations.
Publisher: Elsevier BV
Date: 02-2008
DOI: 10.1016/J.SCHRES.2007.10.019
Abstract: It is increasingly recognized that cognitive assessments, unlike symptom ratings, provide a reliable predictor of functional outcome in schizophrenia. This study evaluated the utility of the 'IntegNeuro' computerized test battery for assessing cognition in first episode schizophrenia. We determined the presence of separable factors of general and social cognition, their equivalence to the consensus domains identified by the NIMH MATRICS project, and their effectiveness in predicting real world functional outcomes. Fifty six first episode schizophrenia (FES) patients and 112 matched healthy controls were assessed on the touchscreen-based 'IntegNeuro' cognitive test battery and FES patients for social functioning (SOFAS) and quality of life (WHOQOL-BREF). Principal components analysis identified i) six factors corresponding to MATRICS domains of general cognition ('Information Processing Speed', 'Verbal Recall', 'Working Memory Capacity', 'Sustained Attention/Vigilance', 'Verbal Processing', 'Executive Function'), ii) an 'Emotional Intelligence' factor corresponding to the MATRICS social cognition domain, and iii) an additional 'Sensori-Motor Function' factor of general cognition and 'Negativity' factor of social cognition. Patients showed impairments relative to controls across all factors, but especially for Working Memory Capacity, followed by Verbal Memory, Sustained Attention/Vigilance and Negativity. These factors strongly predicted poorer social functioning in FES, along with poorer quality of life in psychological, social, and health satisfaction facets. The IntegNeuro battery has utility for assessing separable domains of general and social cognition in FES, which are predictive of real world outcomes. Thus, it may be appropriate for clinical application, including in multi-center trials targeting new treatments for cognition in schizophrenia.
Publisher: Elsevier BV
Date: 05-2023
Publisher: American Chemical Society (ACS)
Date: 25-08-2010
DOI: 10.1021/NN101016F
Abstract: Luminescent silicon quantum dots (SiQDs) are gaining momentum in bioimaging applications, based on their unique combination of optical properties and biocompatibility. Here, we report the development of a multimodal probe that combines the optical properties of silicon quantum dots with the superparamagnetic properties of iron oxide nanoparticles to create biocompatible magnetofluorescent nanoprobes. Multiple nanoparticles of each type are coencapsulated within the hydrophobic core of biocompatible phospholipid-polyethyleneglycol (DSPE-PEG) micelles. The size distribution and composition of the magnetofluorescent nanoprobes were characterized by transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS). Enhanced cellular uptake of these probes in the presence of a magnetic field was demonstrated in vitro. Their luminescence stability in a prostate cancer tumor model microenvironment was demonstrated in vivo. This paves the way for multimodal silicon quantum-dot-based nanoplatforms for a variety of imaging and delivery applications.
Publisher: Springer Science and Business Media LLC
Date: 26-01-2022
DOI: 10.1038/S41398-022-01795-3
Abstract: Torture has profound psychological and physiological consequences for survivors. While some brain structures and functions appear altered in torture survivors, it is unclear how torture exposure influences functional connectivity within and between core intrinsic brain networks. In this study, 37 torture survivors (TS) and 62 non-torture survivors (NTS) participated in a resting-state fMRI scan. Data-driven independent components analysis identified active intrinsic networks. Group differences in functional connectivity in the default mode network (DMN), salience network (SN) and central executive network (CEN) of the triple network model, as well any prefrontal network, were examined while controlling for PTSD symptoms and exposure to other potentially traumatic events. The analysis identified 25 networks eight comprised our networks of interest. Within-network group differences were observed in the left CEN (lCEN), where the TS group showed less spectral power in the low-frequency band. Differential internetwork dynamic connectivity patterns were observed, where the TS group showed stronger positive coupling between the lCEN and anterior dorsomedial and ventromedial DMN, and stronger negative coupling between a lateral frontal network and the lCEN and anterior dorsomedial DMN (when contrasted with the NTS group). Group differences were not attributed to torture severity or dissociative symptoms. Torture survivors showed disrupted dynamic functional connectivity between a laterally-aligned lCEN that serves top-down control functions over external processes and the midline DMN that underpins internal self-referential processes, which may be an adaptive response to mitigate the worst effects of the torture experience. This study provides a critical step in mapping the neural signature of torture exposure to guide treatment development and selection.
Publisher: Springer Science and Business Media LLC
Date: 09-04-2014
Publisher: Springer Science and Business Media LLC
Date: 06-2010
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 2005
DOI: 10.1097/00001756-200501190-00012
Abstract: It is not known how the brain and autonomic systems interact during perception of facial signals of danger. We recorded blood-oxygen-level-dependent (BOLD) activity using fMRI and simultaneous skin conductance measures of autonomic arousal in healthy subjects. Distinct response profiles were elicited for fear (enhanced arousal with amygdala activity), anger (rapid onset, slow recovery arousal responses with anterior cingulate) and disgust (delayed arousal responses with insula and basal ganglia activity). The findings suggest that fear, anger and disgust perception involves specific interactions in the neural arousal systems for emotion and motivation.
Publisher: American Psychiatric Association Publishing
Date: 03-2004
DOI: 10.1176/APPI.AJP.161.3.480
Abstract: The authors investigated impaired differentiation of limbic-prefrontal systems by autonomic arousal in schizophrenia. It was predicted that paranoid patients would be distinguished by a disjunction of hyperarousal but reduced amygdala and medial prefrontal activity relative to both healthy comparison subjects and patients with nonparanoid schizophrenia. Pictures depicting facial expressions of fear were presented to 27 schizophrenia patients (13 paranoid, 14 nonparanoid) and 22 matched healthy comparison subjects in an implicit perception task to evoke limbic activity. Simultaneous functional magnetic resonance imaging and skin conductance arousal recordings were acquired during presentation of faces expressing fear or neutral emotion. Responses to fear stimuli were further examined by contrasting those that were associated with a skin conductance response ("with arousal") and those that were not ("without arousal"). In the comparison subjects, arousal dissociated amygdala/medial prefrontal ("visceral") networks and hippoc us/lateral prefrontal ("context") networks for fear perception. Excessive arousal responses were elicited in the schizophrenia subjects, but there was an associated reduction in amygdala/medial prefrontal activity. This disjunction was pronounced in paranoid patients relative to both healthy subjects and nonparanoid patients. Paranoid patients also showed a relatively greater prefrontal deficit for "without-arousal" responses. This is the first study to reveal a functional disconnection in autonomic and central systems for processing threat-related signals in patients with paranoid schizophrenia. Paranoid cognition may reflect an internally generated cycle of misattribution regarding incoming fear signals due to a breakdown in the regulation of these systems.
Publisher: Informa UK Limited
Date: 25-11-2022
Publisher: Elsevier BV
Date: 10-2017
DOI: 10.1016/J.BIOPSYCHO.2017.07.023
Abstract: Cultures differ substantially in representations of the self. Whereas in idualistic cultural groups emphasize an independent self, reflected in processing biases towards centralized salient objects, collectivistic cultures are oriented towards an interdependent self, attending to contextual associations between visual cues. It is unknown how these perceptual biases may affect brain activity in response to negative social cues. Moreover, while some studies have shown that in idual differences in self-construal moderate cultural group comparisons, few have examined self-construal differences separate to culture. To investigate these issues, a final s le of a group of healthy participants high in trait levels of collectivistic self-construal (n=16) and in idualistic self-construal (n=19), regardless of cultural background, completed a negative social cue evaluation task designed to engage face/object vs context-specific neural processes whilst undergoing fMRI scanning. Between-group analyses revealed that the collectivistic group exclusively engaged the parahippoc al gyrus (parahippoc al place area) - a region critical to contextual integration - during negative face processing - suggesting compensatory activations when contextual information was missing. The collectivist group also displayed enhanced negative context dependent brain activity involving the left superior occipital gyrus/cuneus and right anterior insula. By contrast, the in idualistic group did not engage object or localized face processing regions as predicted, but rather demonstrated heightened appraisal and self-referential activations in medial prefrontal and temporoparietal regions to negative contexts - again suggesting compensatory processes when focal cues were absent. While in idualists also appeared more sensitive to negative faces in the scenes, activating the right middle cingulate gyrus, dorsal prefrontal and parietal activations, this activity was observed relative to the scrambled baseline, and given that prefrontal and occipital regions were also engaged to neutral stimuli, may suggest an in idualistic pattern to processing all social cues more generally. These findings suggest that in idual differences in self-construal may be an important organizing framework facilitating perceptual processes to emotionally salient social cues, beyond the boundary of cultural group comparisons.
Publisher: Elsevier BV
Date: 2005
DOI: 10.1016/J.NEUROIMAGE.2004.08.016
Abstract: We examined whether consciously undetected fear signals engage a collateral brainstem pathway to the amygdala and prefrontal cortex in the intact human brain, using functional neuroimaging. 'Blindsight' lesion patients can respond to visual fear signals independently from conscious experience, suggesting that these signals reach the amygdala via a direct pathway that bypasses the primary visual cortex. Electrophysiological evidence points to concomitant involvement of prefrontal regions in automatic orienting to subliminal signals of fear, which may reflect innervation arising from brainstem arousal systems. To approximate blindsight in 22 healthy subjects, facial signals of fear were presented briefly (16.7 ms) and masked such that conscious detection was prevented. Results revealed that subliminal fear signals elicited activity in the brainstem region encompassing the superior colliculus and locus coeruleus, pulvinar and amygdala, and in fronto-temporal regions associated with orienting. These findings suggest that crude sensory input from the superior colliculo-pulvinar visual pathway to the amygdala may allow for sufficient appraisal of fear signals to innervate the locus coeruleus. The engagement of the locus coeruleus could explain the observation of diffuse fronto-temporal cortical activity, given its role in evoking collateral ascending noradrenergic efferents to the subcortical amygdala and prefrontal cortex. This network may represent an evolutionary adaptive neural 'alarm' system for rapid alerting to sources of threat, without the need for conscious appraisal.
Publisher: Public Library of Science (PLoS)
Date: 05-09-2018
Publisher: Informa UK Limited
Date: 24-08-2011
DOI: 10.3109/08820139.2011.604863
Abstract: Inhibition of Matrix metalloproteinase-9 (MMP-9) activity using delivery of short interfering RNA (siRNA) molecules to brain microvascular endothelial cells (BMVECs) that constitute the BBB may have a significant impact on reducing the BBB permeability. Gold nano rods (GNRs) can electrostatically bind with MMP-9 siRNA to form a nanoplex and the uptake of this nanoplex by BMVEC cells can result in suppression of MMP-9 expression. The current study explores if this GNR-MMP-9 siRNA nanoplex gene silencing modulates the expression of tight junction (TJ) proteins in the BMVEC. The endothelial TJ's of the BBB play a critical role in controlling cellular traffic into the central nervous system. We hypothesize that silencing of the MMP-9 gene expression in BMVEC will increase the expression of TJ proteins thereby decrease endothelial permeability. Our results showed a significant increase in the gene and protein expression of TJ proteins: ZO-1, Occludin and Claudin-5 in BMVEC cells that were transfected with the GNRs-siRNA-MMP-9 nanoplex suggesting that BBB disruption, which results from loss of TJ function due to MMP-9 activation during neuroinflammation can be prevented by silencing MMP-9 expression.
Publisher: Springer Science and Business Media LLC
Date: 13-11-2021
DOI: 10.1038/S41398-021-01715-X
Abstract: Previous studies have shown that activating the attachment system attenuates fear learning. This study aimed to explore whether attachment priming can also impact on fear extinction processes, which underpin the management of anxiety disorders. In this study, 81 participants underwent a standard fear conditioning and extinction protocol on day 1 and returned 24 h later for an extinction recall and reinstatement test. Half the participants were primed to imagine their closest attachment figure prior to undergoing extinction training, while the other half were instructed to imagine a positive situation. Fear-potentiated startle and subjective expectancies of shock were measured as the primary indicators of fear. Attachment priming led to less relapse during the reinstatement test at the physiological but not subjective levels. These findings have translational potential to imply that activating awareness of attachment figures might augment long-term safety memories acquired in existing treatments to reduce relapse of fear.
Publisher: World Scientific Pub Co Pte Lt
Date: 03-2007
DOI: 10.1142/S021963520700143X
Abstract: To examine how general (e.g., memory, attention) and social (emotional and interpersonal processes) cognition relate to measures of brain function and structure. PCA was used to identify general and social cognitive factors from Brain Resource International Database in 1,316 subjects. The identified factors were correlated with each subject's corresponding brain structure (MRI) and function (EEG/ERP) data. Seven core cognitive factors were identified for general and three for social. General cognition was correlated with global grey matter, while social cognition was negatively correlated with grey matter in fronto-temporal-somatosensory regions. Executive function, information processing speed and verbal memory performance were correlated with delta-theta qEEG, while most general cognitive factors negatively correlated with beta qEEG. Faster information processing speed was correlated with alpha qEEG. Executive function and information processing speed was correlated with negative-going ERP litude and slower ERP latency at frontal sites, but at posterior sites negative correlations were found. In contrast to general cognition, social cognition is identified by different functional (automated) activity and more localized neural structures. Only general cognition, requiring more effortful, controlled processing is related to brain function measures, particularly in frontal cortices. Recording measures from multiple modalities including MRI, EEG/ERP, social and general cognition within the same subject provides a method of brain profiling for use in cognitive-neurotherapy and pharmacological studies.
Publisher: Public Library of Science (PLoS)
Date: 07-08-2013
Publisher: Hindawi Limited
Date: 10-08-2018
DOI: 10.1002/DA.22787
Abstract: Refugees are often exposed to multiple traumatic experiences, leading to elevated rates of psychological disorders. There is emerging evidence that appraisals of traumatic events as violating deeply held moral beliefs and frameworks (i.e., moral injury) impact negatively on refugee mental health. Despite this, no research has systematically investigated moral injury appraisals in refugees. Participants were 222 refugees from erse backgrounds who had recently resettled in Australia. They completed measures of mental health in Arabic, Farsi, Tamil, or English through an online survey. This study first investigated the factor structure of the Moral Injury Appraisals Scale (MIAS), and then examined the relationship between the moral injury factors and key predictor (age, gender, trauma exposure) and outcome (Posttraumatic stress disorder [PTSD] symptom clusters, anger, and depression) variables. Confirmatory factor analyses of the MIAS supported a two-factor model, comprising a Moral Injury-Other (MI-Other) factor (i.e., interpreting the violation as being enacted by others) and a Moral Injury-Self (MI-Self) factor (i.e., interpreting the violation as being enacted by oneself). Structural equation modeling analyses indicated that both factors were predicted by higher trauma exposure, and both predicted more severe anger and depression. Notably, while MI-Other was associated with more severe PTSD, MI-Self was associated with lower levels of intrusions. These results suggest that there may be subtypes of moral injury appraisals that are associated with different mental health outcomes. These findings have potential implications for designing treatments that address the psychological impact of the refugee experience.
Publisher: American Chemical Society (ACS)
Date: 25-04-2008
DOI: 10.1021/JP712090Y
Publisher: Elsevier BV
Date: 05-2018
DOI: 10.1016/J.JAD.2018.02.010
Abstract: Although elevated rates of posttraumatic stress disorder (PTSD) have been well-documented in refugees, no study has investigated the heterogeneity of DSM-5 PTSD symptomatology in such populations. This study aimed to determine whether there are unique patterns of DSM-5 defined PTSD symptomatology in refugees, and investigate whether factors characteristic of the refugee experience, including trauma exposure and post-migration stress, predict symptom profiles. Participants were 246 refugees and asylum-seekers from an Arabic-, English-, Farsi-, or Tamil-speaking background who had been resettled in Australia. Participants completed measures of post-migration living difficulties, trauma exposure, PTSD symptoms and functional disability. Latent class analysis was used to identify PTSD symptom profiles, and predictors of class membership were elucidated via multinomial logistic regression. Four classes were identified: a high-PTSD class (21.3%), a high-re-experiencing/avoidance class (15.3%), a moderate-PTSD class (23%), and a no PTSD class (40.3%). Trauma exposure and post-migration stress significantly predicted class membership and classes differed in degree of functional disability. The current study employed a cross-sectional design, which precluded inferences regarding the stability of classes of PTSD symptomatology. This study provides evidence for distinct patterns of PTSD symptomatology in refugees. We identified a novel class, characterized by high-re-experiencing and avoidance symptoms, as well as classes characterized by pervasive, moderate, and no symptomatology. Trauma exposure and post-migration stress differentially contributed to the emergence of these profiles. In iduals with high and moderate probability of PTSD symptoms evidenced substantial disability. These results support conceptualizations of PTSD as a heterogeneous construct, and highlight the importance of considering sub-clinical symptom presentations, as well as the post-migration environment, in clinical contexts.
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3AN01030A
Abstract: This work reports the study of optimization of the reaction parameters on the synthesis of high quality CuInS2 and AgInS2 nanocrystals for bioimaging applications. The concentration of reaction precursors (e.g. Ag, Cu, In and S) plays a key role in determining the emission profile of these ternary quantum dots (QDs). By carefully varying the precursor compositions, the emission of QD can be tuned from red to near infrared (NIR) region. Taking the advantages of NIR emission, which possesses minimal absorption in biological tissues, we have also prepared water-dispersible CuInS2/ZnS and AgInS2/ZnS nanocrystals and demonstrated the high biocompatibility for both deep tissue penetration and tumor targeting. The QDs were stabilized in Pluronic F127 block copolymer micelles, offering us optically and colloidally stable contrast agents for in vitro and in vivo imaging. Two-photon excitation of QD has also been demonstrated, accomplishing a NIR-to-NIR transaction. This study devotes the key steps in promoting the use of ternary QDs as low-toxic, photostable, and cadmium-free semiconductor nanocrystal formulation for multiple imaging applications.
Publisher: Wiley
Date: 02-06-2009
Abstract: Semiconductor quantum dots (QDs) have traditionally been synthesized in organic phase and transferred to aqueous solution by functionalizing their surface with silica, polymers, short-chain thiol ligand, or phospholipid micelles. However, these complex steps result in i) a reduction of the quantum yield (QY) of QDs, ii) partial degrdation of the QDs, and iii) a drastic increase in the hydrodynamic size of QDs, which may hinder their biomedical applications. In this work, the fabrication and applications of cysteine-capped CdTe/ZnTe QDs, which are directly synthesized in aqueous media, as optical probes for specific targeting of pancreatic and esophageal cancer cells in vitro are reported, as well as their capability for in vivo imaging. The CdTe/ZnTe QDs are synthesized in a one-pot method and capped with amino acid cysteine, which contains both carboxyl and amine functional groups on their surfaces for bioconjugation. The fabricated QDs have an ultrasmall hydrodynamic diameter (3-5 nm), possess high QY (52%), and are non-toxic to cells at experimental dosages. Confocal imaging is used to demonstrate a receptor-mediated uptake of antibody-conjugated QDs into pancreatic cancer cells in vitro. In vitro cytotoxicity studies (MTS-assay) show that the IC(50) value of these QDs is approximately 160 microg mL(-1), demonstrating low toxicity. In addition, the QDs are used for small-animal imaging where the in vivo biocompatiblity of these QDs and their clearance following systemic injection is studied.
Publisher: Springer Science and Business Media LLC
Date: 18-10-2016
DOI: 10.1038/TP.2016.149
Publisher: Informa UK Limited
Date: 11-11-2019
Publisher: SAGE Publications
Date: 05-2017
Abstract: While cognitive reappraisal represents a promising emotion regulation strategy to assist refugees with posttraumatic stress disorder (PTSD) in managing responses to trauma reminders, there has been no experimental research investigating its efficacy in reducing intrusions and negative affect in this group. In this study, 76 refugees and asylum-seekers with varying levels of PTSD received instructions in cognitive reappraisal or emotional suppression before viewing emotional images depicting trauma-related scenes. Findings indicated that cognitive reappraisal led to fewer subsequent image-related intrusions in refugees high in PTSD symptoms. Trait suppression moderated the efficacy of cognitive reappraisal such that participants high in PTSD who had low levels of trait suppression reported significantly lower levels of negative affect when using cognitive reappraisal compared to emotional suppression. These findings highlight the potential utility of cognitive reappraisal when assisting in iduals with PTSD to manage responses trauma reminders and for informing the treatment of the psychological effects of the refugee experience.
Publisher: The American Association of Immunologists
Date: 15-04-2012
Abstract: Morphine is a widely abused, addictive drug that modulates immune function. Macrophages are a primary reservoir of HIV-1 therefore, they play a role in the development of this disease, as well as impact the overall course of disease progression. Galectin-1 is a member of a family of β-galactoside–binding lectins that are soluble adhesion molecules and that mediate direct cell–pathogen interactions during HIV-1 viral adhesion. Because the drug abuse epidemic and the HIV-1 epidemic are closely interrelated, we propose that increased expression of galectin-1 induced by morphine may modulate HIV-1 infection of human monocyte-derived macrophages (MDMs). In this article, we show that galectin-1 gene and protein expression are potentiated by incubation with morphine. Confirming previous studies, morphine alone or galectin-1 alone enhance HIV-1 infection of MDMs. Concomitant incubation with exogenous galectin-1 and morphine potentiated HIV-1 infection of MDMs. We used a nanotechnology approach that uses gold nanorod–galectin-1 small interfering RNA complexes (nanoplexes) to inhibit gene expression for galectin-1. We found that nanoplexes silenced gene expression for galectin-1, and they reversed the effects of morphine on galectin-1 expression. Furthermore, the effects of morphine on HIV-1 infection were reduced in the presence of the nanoplex.
Publisher: Elsevier BV
Date: 08-2017
DOI: 10.1016/J.JANXDIS.2017.04.005
Abstract: This study investigated the conceptualization of emotion regulation difficulties in a s le of refugees with varying levels of posttraumatic stress (PTS), and examined whether specific emotion regulation difficulties were associated with PTS severity. Refugees were administered an abbreviated version of the Difficulties in Emotion Regulation Scale, the PTSD Symptom Scale - Interview Version, and the Harvard Trauma Questionnaire. Confirmatory Factor Analysis was used to examine model fit for the 6-factor model originally proposed by the developers of the DERS and the more recently proposed 5-factor model that excludes the awareness subscale. Both models displayed adequate fit. After controlling for age, gender, time in Australia, and trauma exposure, the clarity and strategies subscales were significantly associated with PTS severity. The association between impaired emotional clarity and reduced agency related to accessing regulation strategies and PTS severity in this refugee s le highlights the need for further research to assess interventions that target these disruptions in refugees.
Publisher: Wiley
Date: 24-05-2008
DOI: 10.1002/HBM.20415
Publisher: World Scientific Pub Co Pte Lt
Date: 03-2007
DOI: 10.1142/S0219635207001465
Abstract: There is little consensus about which objective markers should be used to assess major psychiatric disorders, and predict/evaluate treatment response for these disorders. Clinical practice relies instead on subjective signs and symptoms, such that there is a "translational gap" between research findings and clinical practice. This gap arises from: a) a lack of integrative theoretical models which provide a basis for understanding links between gene-brain-behavior mechanisms and clinical entities b) the reliance on studying one measure at a time so that linkages between markers are their specificity are not established and c) the lack of a definitive understanding of what constitutes normative function. Here, we draw on a standardized methodology for acquiring multiple sources of genomic, brain and behavioral data in the same subjects, to propose candidate markers of selected psychiatric disorders: depression, post-traumatic stress disorder, schizophrenia, attention-deficit/hyperactivity disorder and dementia disorders. This methodology has been used to establish a standardized international database which provides a comprehensive framework and the basis for testing hypotheses derived from an integrative theoretical model of the brain. Using this normative base, we present preliminary findings for a number of disorders in relation to the proposed markers. Establishing these objective markers will be the first step towards determining their sensitivity, specificity and treatment prediction in in idual patients.
Publisher: SAGE Publications
Date: 21-04-2023
DOI: 10.1177/21677026231164393
Abstract: Although emotion dysregulation has been robustly associated with posttraumatic stress disorder (PTSD), there is relatively little understanding of this process in refugees. Specifically, longitudinal methodology has not been used to examine the relationship between emotion dysregulation and PTSD among refugees. In this study, we investigated the temporal relationship between emotion dysregulation, postmigration stressors, and PTSD clusters (reexperiencing, avoidance, negative alterations in mood and cognition [NAMC], and hyperarousal) from the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders among a community s le of refugees ( N = 1,081) over a 2-year period. Random intercept cross-lagged panel analysis found that emotion dysregulation was antecedent to within-persons increases in reexperiencing and NAMC symptoms over time and bidirectionally associated with hyperarousal and postmigration stressors. In addition, postmigration stressors were antecedent to within-persons increases in reexperiencing, avoidance, and NAMC and bidirectionally associated with hyperarousal symptoms. Findings provide novel evidence in support of postmigration stressors and emotion dysregulation as mechanisms maintaining PTSD and highlight the potential utility of tailoring interventions to address these factors.
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C2RA21990E
Publisher: Ivyspring International Publisher
Date: 2012
DOI: 10.7150/THNO.3692
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C2CS35392J
Abstract: Tremendous research efforts have been devoted to fabricating high quality quantum dots (QDs) for applications in biology and medicine. Much of this research was pursued with an ultimate goal of using QDs in clinical applications. However, a great deal of concern has been voiced about the potential hazards of QDs due to their heavy-metal content. Many studies have demonstrated toxicity of various QDs in cell culture studies. However, in a smaller number of studies using small animal models (mice and rats), no abnormal behaviour or tissue damage was noticed over periods of months after the systemic administration of QDs. Nevertheless, the correlation of these results with the potential for negative effects of QD on humans remains unclear. Many urgent questions must be answered before the QDs community moves into the clinical research phase. This review provides an overview of the toxicity assessment of QDs, ranging from cell culture studies to animal models and discusses their findings. Guidelines for using various nonhuman primate models for QD toxicity studies are highlighted. This review article is intended to promote the awareness of current developments of QD applications in biology, the potential toxicity of QDs, and approaches to minimizing toxicity.
Publisher: Ivyspring International Publisher
Date: 2012
DOI: 10.7150/THNO.3459
Publisher: Wiley
Date: 28-09-2010
Abstract: Over the past few years, CdTe quantum dots have been demonstrated as powerful probes for biophotonics applications. The aqueous phase synthesis technique remains the best approach to make high quality CdTe QDs in a single‐pot process. CdTe QDs prepared directly in the aqueous phase can have quantum yield as high as 80%. In addition, the surface of CdTe QDs prepared using the aqueous phase technique is functionalized with reactive groups that enable them to be directly conjugated with specific ligands for targeted delivery and sensing. In this contribution, we review recent progress in fabricating aqueous CdTe QDs and exploiting their optical properties in novel approaches to biomedical imaging and sensing applications. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Publisher: Ivyspring International Publisher
Date: 2012
DOI: 10.7150/THNO.3456
Publisher: Elsevier BV
Date: 03-2018
DOI: 10.1016/J.JBTEP.2017.08.004
Abstract: Despite the prevalence of intrusive memories across psychological disorders, little is known about the neural networks that underpin this form of memory. This study used functional magnetic resonance imaging (fMRI) to identify neural circuits associated with the retrieval of intrusive memories. Participants with moderate levels of anxiety (N = 30) underwent a cold pressor task to induce a physiological stress response, after which they viewed 10 neutral and 10 negative film clips. In a method designed to induce intrusive memories, participants then completed an fMRI scan in which they viewed short (2 s) depictions of neutral components from the original film clips. There were no significant differences in activations during intrusion and non-intrusion responses. Exploratory analyses comparing intrusive responses to neutral stimuli found the insula, inferior frontal gyrus, precuneus, right cerebellum and bilateral supplementary motor area were uniquely activated during experience of intrusions (compared to the neutral cue baseline), whereas no significant activations were in response to negative scenes that did not trigger intrusions. This study did not compare the different neural processes implicated in intrusive and intentional emotional memories. The limited intrusions that could be elicited in the scanning environment restricted the number of trials that could be employed. Although no differences in neural activations were observed between intrusive and non-intrusive responses, the observation of precuneus involvement is consistent with models that propose that intrusive memories are impacted by the extent to which there is contextual integration of the relevant memories.
Publisher: Elsevier BV
Date: 08-2016
DOI: 10.1016/J.PSYCHRES.2016.05.048
Abstract: While clinical reports suggest that torture survivors may try to suppress their emotions during torture, little is known about the use of emotional suppression following torture. In this study, 82 refugees and asylum-seekers (including 33 torture survivors) completed self-report measures of trait suppression, PTSD symptoms and baseline negative affect before being exposed to images depicting scenes of interpersonal trauma. The use of suppression while viewing the images was indexed and negative affect was measured both immediately after viewing the images and following a five minute rest period. Findings indicated that torture survivors did not show higher rates of trait suppression or state emotional suppression during the experimental session compared to non-torture survivors. However, torture survivors who endorsed state suppression higher levels of distress, and this relationship was especially strong for those with more severe PTSD symptoms. In contrast, there was a negative relationship between state suppression and distress for non-torture survivors with high levels of PTSD symptoms. These findings suggest that, while torture exposure does not lead to greater use of suppression, it does influence the impact of suppression on emotional responses to stimuli.
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C1NR00001B
Abstract: In this study QDs were encapsulated in carboxylated PluronicF127 (F127COOH) triblock polymeric micelles and conjugated with anti-mesothelin antibody for the purpose of alleviating potential toxicity, enhancing the stability and improving targeting efficiency of CdTe/ZnS quantum dots (QDs) in tumors. The hiphilic triblock polymer of F127COOH contains hydrophilic carboxylated poly(ethylene oxide) (PEO) and hydrophobic poly(propylene oxide) (PPO) units. After encapsulating QDs into carboxylated F127 (F127COOH-QD) micelles, the particles were conjugated with anti-mesothelin antibodies to allow targeting of cancerous areas. The size of the monodispersed spherical QD-containing micelles was determined to be ∼120 nm by dynamic light scattering (DLS). The critical micelle concentration (CMC) was estimated to be 4.7 × 10(-7) M. In an in vitro study, the anti-methoselin antibody conjugated F127COOH (Me-F127COOH-QD) nanomicelles showed negligible cytotoxicity to pancreatic cancer cells (Panc-1). Confocal microscopy demonstrated that the Me-F127COOH-QD nanomicelles were taken up more efficiently by Panc-1 cells, due to antibody mediated targeting. An in vivo imaging study showed that Me-F127COOH-QD nanomicelles accumulated at the pancreatic tumor site 15 min after intravenous injection. In addition, the low in vivo toxicity of the nanomicellar formulation was evaluated by pathological assays. These results suggest that anti-mesothein antibody conjugated carboxylated F127 nanomicelles may serve as a promising nanoscale platform for early human pancreatic cancer detection and targeted drug delivery.
Publisher: SAGE Publications
Date: 07-2011
DOI: 10.3109/10398562.2011.583076
Abstract: Objective: The task of staff capacity building is particularly important, albeit challenging, in low and middle income countries emerging from prolonged periods of persecution and conflict. Mental health professionals engaged in development and research projects are acutely aware of the impact of past and current conditions including trauma exposure, insecurity, and poverty on the capacity of local workers to acquire and apply skills. In this article we reflect on these challenges by drawing on our experience spanning 10 years of mental health work and capacity building in Timor-Leste. Conclusions: It is important to be proactive in identifying the needs and career objectives of workers early in any development initiative so that an effective program of capacity building can be initiated. Careful consideration needs to be given to ensure a compassionate and considered response to the psychosocial needs of staff, one that takes into account the impact of past trauma, ongoing insecurity and socioeconomic conditions on the capacity of workers to function effectively.
Publisher: Springer Science and Business Media LLC
Date: 20-07-2016
DOI: 10.1007/S11920-016-0723-0
Abstract: Refugees demonstrate high rates of post-traumatic stress disorder (PTSD) and other psychological disorders. The recent increase in forcible displacement internationally necessitates the understanding of factors associated with refugee mental health. While pre-migration trauma is recognized as a key predictor of mental health outcomes in refugees and asylum seekers, research has increasingly focused on the psychological effects of post-migration stressors in the settlement environment. This article reviews the research evidence linking post-migration factors and mental health outcomes in refugees and asylum seekers. Findings indicate that socioeconomic, social, and interpersonal factors, as well as factors relating to the asylum process and immigration policy affect the psychological functioning of refugees. Limitations of the existing literature and future directions for research are discussed, along with implications for treatment and policy.
Publisher: Cambridge University Press (CUP)
Date: 12-2006
Publisher: Elsevier BV
Date: 2013
Publisher: Wiley
Date: 09-11-2006
DOI: 10.1002/HBM.20208
Publisher: Elsevier BV
Date: 05-2005
DOI: 10.1016/J.NEUROIMAGE.2005.01.049
Abstract: Effective perception of fear signals is crucial for human survival and the importance of the amygdala in this process is well documented. Animal, lesion and neuroimaging studies indicate that incoming sensory signals of fear travel from thalamus to amygdala via two neural pathways: a direct subcortical route and an indirect pathway via the sensory cortex. Other lines of research have demonstrated prefrontal modulation of the amygdala. However, no study to date has examined the prefrontal modulation of the thalamo-cortico-amygdala pathways in vivo. We used psychophysiological and physiophysiological interactions to examine the functional connectivity within thalamus, amygdala and sensory (inferior occipital, fusiform) cortices, and the modulation of these networks by the anterior cingulate cortex (ACC). Functional magnetic resonance imaging (fMRI) data were acquired for 28 healthy control subjects during a fear perception task, with neutral as the 'baseline' control condition. Main effect analysis, using a region of interest (ROI) approach, confirmed that these regions are part of a distributed neural system for fear perception. Psychophysiological interactions revealed an inverse functional connectivity between occipito-temporal visual regions and the left amygdala, but a positive connectivity between these visual region and the right amygdala, suggesting that there is a hemispheric specialization in the transfer of fear signals from sensory cortices to amygdala. Physiophysiological interactions revealed a dorsal-ventral ision in ACC modulation of the thalamus-sensory cortex pathway. While the dorsal ACC showed a positive modulation of this pathway, the ventral ACC exhibited an inverse relationship. In addition, both the dorsal and ventral ACC showed an inverse interaction with the direct thalamus-amygdala pathway. These findings suggest that thalamo-amygdala and cortical regions are involved in a dynamic interplay, with functional differentiation in both lateralized and ventral/dorsal gradients. Breakdowns in these interactions may give rise to affect-related symptoms seen in a range of neuropsychiatric disorders.
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2NR31002C
Abstract: Luminescent imaging agents and MRI contrast agents are desirable components in the rational design of multifunctional nanoconstructs for biological imaging applications. Luminescent biocompatible silicon quantum dots (SiQDs) and gadolinium chelates can be applied for fluorescence microscopy and MRI, respectively. Here, we report the first synthesis of a nanocomplex incorporating SiQDs and gadolinium ions (Gd³⁺) for biological applications. The nanoconstruct is composed of a PEGylated micelle, with hydrophobic SiQDs in its core, covalently bound to DOTA-chelated Gd³⁺. Dynamic light scattering reveals a radius of 85 nm for these nanoconstructs, which is consistent with the electron microscopy results depicting radii ranging from 25 to 60 nm. Cellular uptake of the probes verified that they maintain their optical properties within the intracellular environment. The magnetic resonance relaxivity of the nanoconstruct was 2.4 mM⁻¹ s⁻¹ (in terms of Gd³⁺ concentration), calculated to be around 6000 mM⁻¹ s⁻¹ per nanoconstruct. These desirable optical and relaxivity properties of the newly developed probe open the door for use of SiQDs in future multimodal applications such as tumour imaging.
Publisher: Ivyspring International Publisher
Date: 2012
DOI: 10.7150/THNO.4275
Publisher: American Chemical Society (ACS)
Date: 07-12-2010
DOI: 10.1021/NN1018945
Abstract: Quantum dots (QDs) have size-dependent optical properties that make them uniquely advantageous for in vivo targeted fluorescence imaging, traceable delivery, and therapy. The use of group II-VI (e.g., CdSe) QDs for these applications is advancing rapidly. However, group II-VI QDs contain toxic heavy metals that limit their in vivo applications. Thus, replacing these with QDs of a biocompatible semiconductor, such as silicon (Si), is desirable. Here, we demonstrate that properly encapsulated biocompatible Si QDs can be used in multiple cancer-related in vivo applications, including tumor vasculature targeting, sentinel lymph node mapping, and multicolor NIR imaging in live mice. This work overcomes dispersibility and functionalization challenges to in vivo imaging with Si QDs through a unique nanoparticle synthesis, surface functionalization, PEGylated micelle encapsulation, and bioconjugation process that produces bright, targeted nanospheres with stable luminescence and long (>40 h) tumor accumulation time in vivo. Upon the basis of this demonstration, we anticipate that Si QDs can play an important role in more sophisticated in vivo models, by alleviating QD toxicity concerns while maintaining the key advantages of QD-based imaging methods.
Publisher: IOP Publishing
Date: 16-03-2010
DOI: 10.1088/0957-4484/21/14/145105
Abstract: In this paper, we report the use of near-infrared (NIR)-emitting alloyed quantum dots (QDs) as efficient optical probes for high contrast in vivo imaging of tumors. Alloyed CdTe(1 - x)Se(x)/CdS QDs were prepared in the non-aqueous phase using the hot colloidal synthesis approach. Water dispersion of the QDs were accomplished by their encapsulation within polyethyleneglycol (PEG)-grafted phospholipid micelles. For tumor-specific delivery in vivo, the micelle-encapsulated QDs were conjugated with the cyclic arginine-glycine-aspartic acid (cRGD) peptide, which targets the alpha(v)beta(3) integrins overexpressed in the angiogenic tumor vasculatures. Using in vivo NIR optical imaging of mice bearing pancreatic cancer xenografts, implanted both subcutaneously and orthotopically, we have demonstrated that systemically delivered cRGD-conjugated QDs, but not the unconjugated ones, can efficiently target and label the tumors with high signal-to-noise ratio. Histopathological analysis of major organs of the treated mice showed no evidence of systemic toxicity associated with these QDs. These experiments suggest that cRGD-conjugated NIR QDs can serve as safe and efficient probes for optical bioimaging of tumors in vivo. Furthermore, by co-encapsulating these QDs and anticancer drugs within these micelles, we have demonstrated a promising theranostic, nanosized platform for both cancer imaging and therapy.
Publisher: MIT Press - Journals
Date: 04-2004
DOI: 10.1162/089892904322926809
Abstract: Current theories of emotion suggest that threat-related stimuli are first processed via an automatically engaged neural mechanism, which occurs outside conscious awareness. This mechanism operates in conjunction with a slower and more comprehensive process that allows a detailed evaluation of the potentially harmful stimulus (LeDoux, 1998). We drew on the Halgren and Marinkovic (1995) model to examine these processes using event-related potentials (ERPs) within a backward masking paradigm. Stimuli used were faces with fear and neutral (as baseline control) expressions, presented above (supraliminal) and below (subliminal) the threshold for conscious detection. ERP data revealed a double dissociation for the supraliminal versus subliminal perception of fear. In the subliminal condition, responses to the perception of fear stimuli were enhanced relative to neutral for the N2 “excitatory” component, which is thought to represent orienting and automatic aspects of face processing. By contrast, supraliminal perception of fear was associated with relatively enhanced responses for the late P3 “inhibitory” component, implicated in the integration of emotional processes. These findings provide evidence in support of Halgren and Marinkovic's temporal model of emotion processing, and indicate that the neural mechanisms for appraising signals of threat may be initiated, not only automatically, but also without the need for conscious detection of these signals.
Publisher: American Chemical Society (ACS)
Date: 27-04-2011
DOI: 10.1021/NN2009485
Abstract: In this study, we report the development of a nanoparticle-enhanced biosensor by integrating both the nanoparticles and immunoassay sensing technologies into a phase interrogation surface plasmon resonance (SPR) system for detecting antigen at a concentration as low as the femtomolar range. Our work has demonstrated that the plasmonic field extension generated from the gold film to gold nanorod (GNR) has led to a drastic sensitivity enhancement. Antibody-functionalized sensing film, together with antibody-conjugated GNRs, was readily served as a plasmonic coupling partner that can be used as a powerful ultrasensitive sandwich immunoassay for cancer-related disease detection. Experimentally, it was found that the bioconjugated GNR labels enhance the tumor necrosis factor alpha (TNF-α) antigen signal with more than 40-fold increase compared to the traditional SPR biosensing technique. The underlying principle was analyzed by simulating the near-field coupling between the sensing film and the GNR. The results have shown that GNRs were readily served as promising lification labels in SPR sensing technology.
Publisher: American Chemical Society (ACS)
Date: 08-2007
DOI: 10.1021/JP0733419
Publisher: Springer Science and Business Media LLC
Date: 12-11-2010
Publisher: Elsevier BV
Date: 11-2005
DOI: 10.1016/J.NEUROIMAGE.2005.06.035
Abstract: The amygdala has a key role in regulating arousal and vigilance, and responds to both visual and vocal signals of fear, including facial expressions of fear. In this study, we used functional MRI to examine sex differences in the magnitude, extent, lateralization and time course of amygdala responses to facial signals of fear, in a relatively large s le of males and females. Skin conductance was recorded simultaneously with functional imaging to examine concomitant changes in emotional arousal, and to provide an independent index of response attenuation. Scanning and skin conductance recording was undertaken during perception of facial fear stimuli. Sex differences were apparent in the laterality and time course of fear perception. In males, the right amygdala and autonomic arousal attenuated over the late half of the experiment. By contrast, females showed persistent bilateral amygdala responses, with a tendency towards greater left amygdala engagement during the late phase. Females also showed a greater general extent of amygdala response. We suggest that distinct evolutionary pressures might contribute to a lower threshold for vigilance to signals of danger in females, reflected in a profile of sustained amygdala-arousal interaction.
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3RA41153B
Publisher: Wiley
Date: 20-03-2022
Publisher: Informa UK Limited
Date: 10-2012
DOI: 10.2147/IJN.S25871
Publisher: Elsevier BV
Date: 02-2007
DOI: 10.1016/J.SCHRES.2006.11.023
Abstract: Schizophrenia patients show reduced neural activity, relative to controls, in the amygdala and its projection to the medial prefrontal cortex (MPFC) in response to fear perception. In this study we tested the hypothesis that schizophrenia is characterized by abnormal functional connectivity in the amygdala network underlying fear perception. Functional MRI images were acquired from 14 schizophrenia patients and 14 matched healthy control subjects during an emotion perception task, in which fearful and neutral facial expression stimuli were presented pseudorandomly under nonconscious (using masking) and conscious conditions. Both subtraction and functional connectivity analyses were undertaken using a region of interest approach. In response to fearful facial expressions, schizophrenia patients displayed reduced amygdala activity, compared to controls, in both the conscious and nonconscious conditions. The amygdala displayed a reversal of the normal pattern of connectivity with the brainstem, visual cortex, and also with the dorsal and ventral isions of the MPFC in the schizophrenia patients. The presence of functional disconnections in amygdala pathways suggests that schizophrenia patients have a failure in coordinating their automatic orienting to salient signals and the associated prefrontal monitoring of these signals.
Publisher: Springer Science and Business Media LLC
Date: 12-06-2012
Publisher: American Society of Clinical Oncology (ASCO)
Date: 07-2015
Abstract: As glioblastoma progresses, patients experience a decline in health-related quality of life (HRQoL). Delaying this decline is an important treatment goal. In newly diagnosed glioblastoma, progression-free survival was prolonged when bevacizumab was added to radiotherapy plus temozolomide (RT/TMZ) versus placebo plus RT/TMZ (phase III AVAglio study hazard ratio, 0.64 95% CI, 0.55 to 0.74 P .001). To ensure that addition of bevacizumab to standard-of-care therapy was not associated with HRQoL detriment, HRQoL assessment was a secondary objective. Patients completed European Organisation for Research and Treatment of Cancer Quality of Life Questionnaires C30 and BN20 at each tumor assessment (Appendix Table A1 , online only). Raw scores were converted to a 100-point scale and mean changes from baseline scores were evaluated (stable: 10-point change clinically relevant deterioration/improvement: ≥ 10-point change). Deterioration-free survival was the time to deterioration rogression/death time to deterioration was the time to deterioration/death. Most evaluable patients who had not progressed ( 74%) completed all HRQoL assessments for at least 1 year of treatment, and almost all completed at least one HRQoL assessment at baseline (98.3% and 97.6%, bevacizumab and placebo arms, respectively). Mean changes from baseline did not reach a clinically relevant difference between arms for most items. HRQoL declined at progression in both arms. The addition of bevacizumab to RT/TMZ resulted in statistically longer (P .001) deterioration-free survival across all items. Time to deterioration was not statistically longer in the placebo plus RT/TMZ arm (v bevacizumab) for any HRQoL item. The addition of bevacizumab to standard-of-care treatment for newly diagnosed glioblastoma had no impact on HRQoL during the progression-free period.
Publisher: American Chemical Society (ACS)
Date: 25-02-2009
DOI: 10.1021/NN8008933
Publisher: Elsevier BV
Date: 02-2011
Publisher: Wiley
Date: 11-02-2021
DOI: 10.1002/VIW.20200111
Publisher: Wiley
Date: 13-09-2022
Publisher: Society for Neuroscience
Date: 14-06-2006
Publisher: Elsevier BV
Date: 05-2014
Publisher: Oxford University Press (OUP)
Date: 2012
DOI: 10.1039/C1IB00060H
Abstract: Radiation therapy (RT) is an important treatment modality used against a number of human cancers, including head and neck squamous cell carcinoma (HNSCC). However, most of these cancers have an inherent anti-apoptotic mechanism that makes them resistant to radiation therapy. This radioresistance of cancer cells necessitates the irradiation of tumor areas with extremely high doses of radiation to achieve effective therapy, resulting in damage to normal tissues and leading to several treatment related side effects. These side effects significantly impair the quality of life of treated patients, and preclude the possibility of repeat radiation treatment in patients with tumor recurrence. Our previous research has correlated the upregulation of the anti-apoptotic sphingosine kinase (SphK1) gene in HNSCC cells with their radioresistance properties. In the current study, we hypothesized that by downregulating the SphK1 gene using nanotechnology mediated gene silencing, we can render these cells more vulnerable to radiation therapy by enabling apoptosis at lower radiation doses. We have employed biocompatible gold nanorods (GNRs) as carriers of short interfering RNA (siRNA) targeting the SphK1 gene. GNRs play a critical role in protecting the siRNA molecules against physiological degradation, as well as delivering them inside target cells. Following their synthesis and characterization, these nanoplexes were applied to HNSCC cells in culture, resulting in the radiosensitization of the treated cells. Furthermore, the GNR-siRNA nanoplexes were injected intratumorally into subcutaneous HNSCC tumors grown in mice, prior to the initiation of radiation therapy in vivo. Subsequent exposure of GNR-SphK1siRNA nanoplex-treated tumors to radiation (GNR-SphK1siRNA + IRRA) resulted in over 50% tumor regression compared to control GNR-GFPsiRNA nanoplex and radiation treated tumors (GNR-GFPsiRNA + IRRA). In addition, we were able to induce this tumor regression in nanoplex treated tumors with radiation doses much lower than those commonly required in clinical RT. These experiments lay the foundation for the development of a nanotechnology-mediated gene silencing tool for more potent radiation therapy of a number of human cancers, with minimal, if any, toxic side effects.
Publisher: Cambridge University Press (CUP)
Date: 30-08-2018
DOI: 10.1017/S0033291718002246
Abstract: The mental health and social functioning of millions of forcibly displaced in iduals worldwide represents a key public health priority for host governments. This is the first longitudinal study with a representative s le to examine the impact of interpersonal trust and psychological symptoms on community engagement in refugees. Participants were 1894 resettled refugees, assessed within 6 months of receiving a permanent visa in Australia, and again 2–3 years later. Variables measured included post-traumatic stress disorder symptoms, depression/anxiety symptoms, interpersonal trust and engagement with refugees’ own and other communities. A multilevel path analysis was conducted, with the final model evidencing good fit (Comparative Fit Index = 0.97, Tucker–Lewis Index = 0.89, Root Mean Square Error of Approximation = 0.05, Standardized Root-Mean-Square-Residual = 0.05). Findings revealed that high levels of depression symptoms were associated with lower subsequent engagement with refugees’ own communities. In contrast, low levels of interpersonal trust were associated with lower engagement with the host community over the same timeframe. Findings point to differential pathways to social engagement in the medium-term post-resettlement. Results indicate that depression symptoms are linked to reduced engagement with one's own community, while interpersonal trust is implicated in engagement with the broader community in the host country. These findings have potentially important implications for policy and clinical practice, suggesting that clinical and support services should target psychological symptoms and interpersonal processes when fostering positive adaptation in resettled refugees.
Publisher: Wiley
Date: 02-2019
DOI: 10.1002/JTS.22371
Abstract: Refugees who suffer from posttraumatic stress disorder (PTSD) often react with strong emotions when confronted with trauma reminders. In this study, we aimed to investigate the associations between low emotion regulation capacity (as indexed by low heart rate variability [HRV]), probable PTSD diagnosis, and fear and anger reaction and recovery to trauma-related stimuli. Participants were 81 trauma-exposed refugees (probable PTSD, n = 23 trauma-exposed controls, n = 58). The experiment comprised three 5-min phases: a resting phase (baseline) an exposition phase, during which participants were exposed to trauma-related images (stimulus) and another resting phase (recovery). We assessed HRV at baseline, and fear and anger were rated at the end of each phase. Linear mixed model analyses were used to investigate the associations between baseline HRV and probable DSM-5 PTSD diagnosis in influencing anger and fear responses both immediately after viewing trauma-related stimuli and at the end of the recovery phase. Compared to controls, participants with probable PTSD showed a greater increase in fear from baseline to stimulus presentation, d = 0.606. Compared to participants with low emotion regulation capacity, participants with high emotion regulation capacity showed a smaller reduction in anger from stimulus presentation to recovery, d = 0.548. Our findings indicated that following exposure to trauma-related stimuli, probable PTSD diagnosis predicted increased fear reactivity, and low emotion regulation capacity predicted decreased anger recovery. Impaired anger recovery following trauma reminders in the context of low emotion regulation capacity might contribute to the increased levels of anger found in postconflict s les.
Publisher: SAGE Publications
Date: 28-10-2021
Abstract: Many refugees experience prolonged separation from family members, which research suggests has adverse effects on mental health and post-displacement outcomes in refugee populations. We examine mental health differences in refugees separated and not separated from their families, and key post-migration factors and cultural mechanisms that may underlie this impact. A s le of 1085 refugees resettled in Australia, of which 23.3% were separated from all of their immediate family, took part in an online battery of survey measures indexing pre- and post-migration refugee experiences, mental health symptoms, disability and in idualistic/collectivistic self-identity. Family separation was used as a predictor of mental health outcomes in a series of linear regressions, and the separated and non-separated groups were compared in multigroup path analysis models to examine group-specific indirect effects. The separated group reported greater exposure to pre-migration potentially traumatic events and higher levels of post-migration living difficulties compared to the non-separated group. Family separation predicted higher post-traumatic stress and depression symptoms, but not disability, after controlling for potentially traumatic event exposure, age and sex. Path analyses revealed distinct indirect effects for separated and non-separated groups. Principally, higher collectivistic self-identity was associated with elevated post-traumatic stress, depression and disability symptoms via social-related post-migration living difficulties such as isolation and loneliness in the separated group whereas collectivism was linked with increased depression symptoms via economic-related post-migration living difficulties in the non-separated group. These findings indicate that family separation powerfully influences mental health outcomes, but that its effect may be mediated by the type of post-migration stress experienced in the settlement environment and culturally bound differences in how the sense of self is interconnected with family.
Publisher: American Psychological Association (APA)
Date: 02-2010
DOI: 10.1037/A0017551
Abstract: Although women have a greater propensity than men to develop posttraumatic stress disorder (PTSD) following trauma, sex differences in neural activations to threat have received little investigation. This study tested the prediction that trauma would heighten activity in automatic fear-processing networks to a greater extent in women than in men. Functional magnetic resonance imaging (fMRI) data were recorded in 23 participants with PTSD (13 women, 10 men), 21 trauma-exposed controls (9 women, 12 men), and 42 non-trauma-exposed controls (22 women, 20 men) while they viewed masked facial expressions of fear. Exposure to trauma was associated with enhanced brainstem activity to fear in women, regardless of the presence of PTSD, but in men, it was associated only with the development of PTSD. Men with PTSD displayed greater hippoc al activity to fear than did women. Both men and women with PTSD showed enhanced amygdala activity to fear relative to controls. The authors conclude that greater brainstem activation to threat stimuli may contribute to the greater prevalence of PTSD in women, and greater hippoc al activation in men may subserve an enhanced capacity for contextualizing fear-related stimuli.
Publisher: Elsevier BV
Date: 05-2007
DOI: 10.1016/J.PSCYCHRESNS.2006.12.018
Abstract: Schizophrenia patients show a disconnection in amygdala-medial prefrontal cortex and autonomic arousal systems for processing fear. Concurrent functional magnetic resonance imaging [fMRI] and skin conductance recording were used to determine whether these disturbances are specific to fear, or present in response to other signals of danger. We also examined whether these disturbances distinguish a specific symptom profile. During scanning, 27 schizophrenia (13 paranoid, 14 nonparanoid) and 22 matched healthy control subjects viewed standardized facial expressions of fear, anger and disgust (versus neutral). Skin conductance responses [SCRs]were acquired simultaneously to assess phasic increases in arousal. 'With-arousal' versus 'without-arousal' responses were analysed using non-parametric methods. For controls, 'with-arousal' responses were associated with emotion-specific activity for fear (amygdala), disgust (insula) and anger (anterior cingulate), together with common medial prefrontal cortex [MPFC] engagement, as predicted. Schizophrenia patients displayed abnormally increased phasic arousal, with concomitant reductions in emotion-specific regions and MPFC. These findings may reflect a general disconnection between central and autonomic systems for processing signals of danger. This disjunction was most apparent in patients with a profile of paranoia, coupled with poor social function and insight. Heightened autonomic sensitivity to signals of fear, threat or contamination, without effective neural mechanisms for appraisal, may underlie paranoid delusions which concern threat and contamination, and associated social and interpersonal difficulties.
Publisher: World Scientific Pub Co Pte Lt
Date: 03-2007
DOI: 10.1142/S0219635207001374
Abstract: Increasing age is the strongest risk factor for Alzheimer's disease (AD). Yet, departure from normal age-related decline for established markers of AD including memory, cognitive decline and brain function deficits, has not been quantified. We examined the cross-sectional estimates of the "rate of decline" in cognitive performance and psychophysiological measures of brain function over age in AD, preclinical (subjective memory complaint-SMC, Mild Cognitive Impairment-MCI) and healthy groups. Correlations between memory performance and indices of brain function were also conducted. The rate of cognitive decline increased between groups: AD showed advanced decline, and SMC/MCI groups represented intermediate stages of decline relative to normal aging expectations. In AD, advanced EEG alterations (excessive slow-wave/reduced fast-wave EEG, decreased working memory P450 component) were observed over age, which were coupled with memory decline. By contrast, MCI group showed less severe cognitive changes but specific decreases in the working memory N300 component and slow-wave (delta) EEG, associated with decline in memory. DISCUSSION AND INTEGRATIVE SIGNIFICANCE: While the cognitive data suggests a continuum of deterioration associated with increasing symptom severity across groups, integration with brain function measures points to possible distinct compensatory strategies in MCI and AD groups. An integrative approach offers the potential for objective markers of the critical turning point, with age as a potential factor, from mild memory problems to disease.
Publisher: Hindawi Limited
Date: 05-05-2021
DOI: 10.1002/DA.23166
Publisher: Informa UK Limited
Date: 08-06-2023
Publisher: Elsevier BV
Date: 02-2018
Publisher: Informa UK Limited
Date: 13-06-2016
Abstract: A significant body of literature documents the neural mechanisms involved in the development and maintenance of posttraumatic stress disorder (PTSD). However, there is very little empirical work considering the influence of culture on these underlying mechanisms. Accumulating cultural neuroscience research clearly indicates that cultural differences in self-representation modulate many of the same neural processes proposed to be aberrant in PTSD. The objective of this review paper is to consider how culture may impact on the neural mechanisms underlying PTSD. We first outline five key affective and cognitive functions and their underlying neural correlates that have been identified as being disrupted in PTSD: (1) fear dysregulation (2) attentional biases to threat (3) emotion and autobiographical memory (4) self-referential processing and (5) attachment and interpersonal processing. Second, we consider prominent cultural theories and review the empirical research that has demonstrated the influence of cultural variations in self-representation on the neural substrates of these same five affective and cognitive functions. Finally, we propose a conceptual model that suggests that these five processes have major relevance to considering how culture may influence the neural processes underpinning PTSD.
Publisher: American Chemical Society (ACS)
Date: 29-09-2023
Publisher: Informa UK Limited
Date: 2021
Publisher: Elsevier BV
Date: 11-2009
DOI: 10.1016/J.PSCYCHRESNS.2009.04.012
Abstract: While posttraumatic stress disorder (PTSD) is often characterised by an excessive fear response and hyperarousal, research has generally neglected other clinical characteristics including hypoarousal. Findings indicate that concurrent autonomic activity is associated with increased non-conscious processing of fear, highlighting that autonomic responsivity may be an important determinant in the degree of activation within the brainstem-amygdala-MPFC (medial prefrontal cortex) network.
Publisher: Public Library of Science (PLoS)
Date: 29-09-2016
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 02-2012
Publisher: Informa UK Limited
Date: 15-12-2019
Publisher: MIT Press - Journals
Date: 10-2007
DOI: 10.1162/JOCN.2007.19.10.1595
Abstract: Although biases toward signals of fear may be an evolutionary adaptation necessary for survival, heightened biases may be maladaptive and associated with anxiety or depression. In this study, event-related potentials (ERPs) were used to examine the time course of neural responses to facial fear stimuli (versus neutral) presented overtly (for 500 msec with conscious attention) and covertly (for 10 msec with immediate masking to preclude conscious awareness) in 257 nonclinical subjects. We also examined the impact of trait anxiety and depression, assessed using psychometric ratings, on the time course of ERPs. In the total subject group, controlled biases to overtly processed fear were reflected in an enhancement of ERPs associated with structural encoding (120–220 msec) and sustained evaluation persisting from 250 msec and beyond, following a temporo-occipital to frontal topography. By contrast, covert fear processing elicited automatic biases, reflected in an enhancement of ERPs prior to structural encoding (80–180 msec) and again in the period associated with automatic orienting and emotion encoding (230–330 msec), which followed the reverse frontal to temporo-occipital topography. Higher levels of trait anxiety (in the clinical range) were distinguished by a heightened bias to covert fear (speeding of early ERPs), compared to higher depression which was associated with an opposing bias to overt fear (slowing of later ERPs). Anxiety also heightened early responses to covert fear, and depression to overt fear, with subsequent deficits in emotion encoding in each case. These findings are consistent with neural biases to signals of fear which operate automatically and during controlled processing, feasibly supported by parallel networks. Heightened automatic biases in anxiety may contribute to a cycle of hypervigilance and anxious thoughts, whereas depression may represent a “burnt out” emotional state in which evaluation of fear stimuli is prolonged only when conscious attention is allocated.
Publisher: Springer Science and Business Media LLC
Date: 21-02-2022
Publisher: Springer Science and Business Media LLC
Date: 12-2013
Publisher: Public Library of Science (PLoS)
Date: 14-06-2011
Publisher: Elsevier BV
Date: 05-2006
DOI: 10.1016/J.NEUROIMAGE.2005.12.009
Abstract: We tested the proposal that signals of potential threat are given precedence over positive and neutral signals, reflected in earlier and more pronounced changes in neural activity. The temporal sequence ('when') and source localization ('where') of event-related potentials (ERPs) elicited by fearful and happy facial expressions, compared to neutral control expressions, were examined for 219 healthy subjects. We scored ERPs over occipito-temporal sites (N80, 50-120 ms P120, 80-180 ms N170, 120-220 ms P230, 180-290 ms N250, 230-350 ms) and their polarity-reversed counterparts over medial sites (P80, 40-120 ms N120, 80-150 ms VPP, 120-220 ms N200, 150-280 ms P300, 280-450 ms). In addition to scoring peak litude and latency, the anatomical sources of activity were determined using low resolution brain electromagnetic tomography (LORETA). Fearful faces were distinguished by persistent increases in positivity, associated with a dynamical shift from temporo-frontal (first 120 ms) to more distributed cortical sources (120-220 ms) and back (220-450 ms). By contrast, expressions of happiness produced a discrete enhancement of negativity, later in the time course (230-350 ms) and localized to the fusiform region of the temporal cortex. In common, fear and happiness modulated the face-related N170, and produced generally greater right hemisphere activity. These findings support the proposal that fear signals are given precedence in the neural processing systems, such that processing of positive signals may be suppressed until vigilance for potential danger is completed. While fear may be processed via parallel pathways (one initiated prior to structural encoding), neural systems supporting positively valenced input may be more localized and rely on structural encoding.
Publisher: IOP Publishing
Date: 11-03-2011
DOI: 10.1088/0957-4484/22/16/165101
Abstract: In this study, we have developed a novel carrier, micelle-type bioconjugated PLGA-4-arm-PEG branched polymeric nanoparticles (NPs), for the detection and treatment of pancreatic cancer. These NPs contained 4-arm-PEG as corona, and PLGA as core, the particle surface was conjugated with cyclo(arginine-glycine-aspartate) (cRGD) as ligand for in vivo tumor targeting. The hydrodynamic size of the NPs was determined to be 150-180 nm and the critical micellar concentration (CMC) was estimated to be 10.5 mg l( - 1). Our in vitro study shows that these NPs by themselves had negligible cytotoxicity to human pancreatic cancer (Panc-1) and human glioblastoma (U87) cell lines. Near infrared (NIR) microscopy and flow cytometry demonstrated that the cRGD conjugated PLGA-4-arm-PEG polymeric NPs were taken up more efficiently by U87MG glioma cells, over-expressing the α(v)β(3) integrin, when compared with the non-targeted NPs. Whole body imaging showed that the cRGD conjugated PLGA-4-arm-PEG branched polymeric NPs had the highest accumulation in the pancreatic tumor site of mice at 48 h post-injection. Physical, hematological, and pathological assays indicated low in vivo toxicity of this NP formulation. These studies on the ability of these bioconjugated PLGA-4-arm-PEG polymeric NPs suggest that the prepared polymeric NPs may serve as a promising platform for detection and targeted drug delivery for pancreatic cancer.
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C0AN01017K
Abstract: Recently, multimodal nanoparticles integrating dual- or tri-imaging modalities into a single hybrid nanosystem have attracted plenty of attention in biomedical research. Here, we report the fabrication of two types of multimodal micelle-encapsulated nanoparticles, which were systematically characterized and thoroughly evaluated in terms of their imaging potential and biocompatibility. Optical and magnetic resonance (MR) imaging probes were integrated by conjugating DOTA-gadolinium (Gd) derivative to quantum dot based nanomicelles. Two hiphilic block copolymer micelles, amine-terminated mPEG-phospholipid and amine-modified Pluronic F127, were chosen as the capping agents because of their excellent biocompatibility and ability to prevent opsonization and prolong circulation time in vivo. Owing to their different hydrophobic-hydrophilic structure, the micellar aggregates exhibited different sizes and protection of core QDs. This work revealed the differences between these nanomicelles in terms of the stability over a wide range of pH, along with their cytotoxicity and the capacity for chelating gadolinium, thus providing a useful guideline for tailor-making multimodal nanoparticles for specific biomedical applications.
Publisher: Elsevier BV
Date: 12-2016
DOI: 10.1016/J.JPSYCHIRES.2016.08.011
Abstract: Despite unprecedented numbers of migrants internationally, little is known about the mental health needs of immigrant groups residing in common countries of resettlement. The majority of studies support the 'healthy migrant hypothesis', but few studies have examined: 1) shifts in prevalence patterns across generations 2) how prevalence relates to disability in immigrant groups. Our study examined the prevalence of common mental disorders and disability in first and second generation migrants to Australia. Twelve-month and lifetime prevalence rates of affective, anxiety, and substance use disorders were obtained from the Australian National Survey of Mental Health and Wellbeing (N = 8841). First generation immigrants (born overseas) and second generation immigrants (both parents overseas) from non-English and English speaking backgrounds were compared to an Australian-born cohort. Disability was indexed by days out of role and the WHO Disability Assessment Schedule (WHODAS12). First generation immigrants with non-English speaking (1G-NE) backgrounds evidenced reduced prevalence of common mental disorders relative to the Australian-born population (adjusted odds ratio 0.5 [95% CI 0.38-0.66]). This lower prevalence was not observed in second generation immigrant cohorts. While overall levels of disability were equal between all groups (p > 0.05), mental health-related disability was elevated in the 1G-NE group relative to the Australian-born group (p = 0.012). The findings challenge the overarching notion of the "healthy migrant" and suggest a dissociation between reduced prevalence and elevated mental health-related disability amongst first generation immigrants with non-English speaking backgrounds. These findings highlight the heterogeneous psychiatric needs of first and second generation immigrants.
Publisher: SAGE Publications
Date: 11-09-2020
Abstract: Torture adversely influences emotional functioning, but the neurophysiological mechanisms underpinning its impact are unknown. This study examined how torture exposure affects the neural substrates of interpersonal threat and reward processing. Male refugees with ( N = 31) and without ( N = 27) torture exposure completed a clinical interview and functional magnetic resonance imaging scan where they viewed fear, happy and neutral faces. Between-group activations and neural coupling were examined as moderated by posttraumatic stress disorder symptom severity and cumulative trauma load. Posttraumatic stress disorder symptom severity and trauma load significantly moderated group differences in brain activation and connectivity patterns. Torture survivors deactivated the ventral striatum during happy processing compared to non-torture survivor controls as a function of increased posttraumatic stress disorder symptom severity – particularly avoidance symptoms. The ventral striatum was more strongly coupled with the inferior frontal gyrus in torture survivors. Torture survivors also showed left hippoc al deactivation to both fear and happy faces, moderated by trauma load, compared to controls. Stronger coupling between the hippoc us and frontal, temporoparietal and subcortical regions during fear processing was observed, with pathways being predicted by avoidance and hyperarousal symptoms. Torture exposure was associated with distinct brain activity and connectivity patterns during threat and reward processing, dependent on trauma exposure and posttraumatic stress disorder symptom severity. Torture appears to affect emotional brain functioning, and findings have the potential to guide more targeted interventions for torture survivors.
Publisher: Springer Science and Business Media LLC
Date: 23-05-2018
Publisher: Wiley
Date: 15-12-2003
DOI: 10.1002/HBM.10154
Publisher: Society for Neuroscience
Date: 06-09-2006
DOI: 10.1523/JNEUROSCI.1016-06.2006
Abstract: Many of the same regions of the human brain are activated during conscious attention to signals of fear and in the absence of awareness for these signals. The neural mechanisms that dissociate level of awareness from activation in these regions remain unknown. Using functional magnetic resonance imaging with connectivity analysis in healthy human subjects, we demonstrate that level of awareness for signals of fear depends on mode of functional connectivity in amygdala pathways rather than discrete patterns of activation in these pathways. Awareness for fear relied on negative connectivity within both cortical and subcortical pathways to the amygdala, suggesting that reentrant feedback may be necessary to afford such awareness. In contrast, responses to fear in the absence of awareness were supported by positive connections in a direct subcortical pathway to the amygdala, consistent with the view that excitatory feedforward connections along this pathway may be sufficient for automatic responses to “unseen” fear.
Start Date: 2011
End Date: 2013
Funder: National Health and Medical Research Council
View Funded ActivityStart Date: 2006
End Date: 2019
Funder: Australian Research Council
View Funded ActivityStart Date: 2014
End Date: 2015
Funder: Winston Churchill Memorial Trust
View Funded ActivityStart Date: 07-2018
End Date: 12-2023
Amount: $739,083.00
Funder: Australian Research Council
View Funded ActivityStart Date: 09-2016
End Date: 09-2019
Amount: $568,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 2022
End Date: 12-2025
Amount: $837,040.00
Funder: Australian Research Council
View Funded Activity