ORCID Profile
0000-0001-5154-0291
Current Organisations
Federal University of Maranhão
,
Linköpings universitet
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Publisher: IEEE
Date: 06-2009
Publisher: American Chemical Society (ACS)
Date: 09-03-2023
Publisher: Wiley
Date: 11-1995
Publisher: Wiley
Date: 06-2017
Publisher: Wiley
Date: 09-06-2010
DOI: 10.1111/J.1365-2362.2010.02316.X
Abstract: This study examined the effects of acute supramaximal exercise (approximately 115% VO(2max)) on the blood lipid profile for three different carbohydrate (CHO) storage levels (control, low and high). Six male subjects were randomly ided into three different groups: control, low CHO and high CHO. These groups differed in the diet to which the subjects were submitted before each exercise session. The lipid profile [triglycerides (TG), very low-density lipoprotein (VLDL), high-density lipoprotein (HDL)-cholesterol, low-density lipoprotein (LDL)-cholesterol, TG/HDL-C ratio and total cholesterol) was determined at rest, immediately after exercise and 1 h after exercise bouts. The time to exhaustion was lower in the low CHO condition compared with the control and high CHO condition (3.59 +/- 0.72 2.91 +/- 0.56 and 4.26 +/- 0.69 min P < 0.05). The energy expenditure (control: 251.1 +/- 56.0 kJ low CHO: 215.2 +/- 28.6 kJ and high CHO: 310.4 +/- 64.9 kJ) was significantly different between the low and high CHO conditions (P < 0.05). There were no significant changes in the lipid profile for any of the experimental conditions (control, low and high P 0.05). These results indicate that a supramaximal exercise session has no significant effects on lipid metabolism.
Publisher: American Chemical Society (ACS)
Date: 10-1995
DOI: 10.1021/MA00126A033
Publisher: Springer Science and Business Media LLC
Date: 06-07-2010
DOI: 10.1007/S00726-010-0678-0
Abstract: Amino acids such as leucine and its metabolite α-ketoisocaproate (KIC), are returning to be the focus of studies, mainly because of their anti-catabolic properties, through inhibition of muscle proteolysis and enhancement of protein synthesis. It is clear that these effects may counteract catabolic conditions, as well as enhance skeletal muscle mass and strength in athletes. Moreover, beta-hydroxy-beta-methylbutyrate (HMB) has been shown to produce an important effect in reducing muscle damage induced by mechanical stimuli of skeletal muscle. This review aims to describe the general scientific evidence of KIC and HMB supplementation clinical relevance, as well as their effects (e.g., increases in skeletal muscle mass and/or strength), associated with resistance training or other sports. Moreover, the possible mechanisms of cell signaling regulation leading to increases and/or sparing (during catabolic conditions) of skeletal muscle mass are discussed in detail based on the recent literature.
Publisher: Springer Science and Business Media LLC
Date: 24-06-2009
DOI: 10.1007/S00421-009-1115-5
Abstract: A reduction in LDL cholesterol and an increase in HDL cholesterol levels are clinically relevant parameters for the treatment of dyslipidaemia, and exercise is often recommended as an intervention. This study aimed to examine the effects of acute, high-intensity exercise ( approximately 90% VO(2max)) and varying carbohydrate levels (control, low and high) on the blood lipid profile. Six male subjects were distributed randomly into exercise groups, based on the carbohydrate diets (control, low and high) to which the subjects were restricted before each exercise session. The lipid profile (triglycerides, VLDL, HDL cholesterol, LDL cholesterol and total cholesterol) was determined at rest, and immediately and 1 h after exercise bouts. There were no changes in the time exhaustion (8.00 +/- 1.83 7.82 +/- 2.66 and 9.09 +/- 3.51 min) and energy expenditure (496.0 +/- 224.8 411.5 +/- 223.1 and 592.1 +/- 369.9 kJ) parameters with the three varying carbohydrate intake (control, low and high). Glucose and insulin levels did not show time-dependent changes under the different conditions (P > 0.05). Total cholesterol and LDL cholesterol were reduced after the exhaustion and 1 h recovery periods when compared with rest periods only in the control carbohydrate intake group (P < 0.05), although this relation failed when the diet was manipulated. These results indicate that acute, high-intensity exercise with low energy expenditure induces changes in the cholesterol profile, and that influences of carbohydrate level corresponding to these modifications fail when carbohydrate (low and high) intake is manipulated.
Publisher: Elsevier BV
Date: 06-1999
Publisher: Elsevier BV
Date: 1998
Publisher: Elsevier BV
Date: 04-2010
Publisher: Springer Science and Business Media LLC
Date: 08-12-2013
DOI: 10.1038/NMAT3824
Abstract: Polymers are lightweight, flexible, solution-processable materials that are promising for low-cost printed electronics as well as for mass-produced and large-area applications. Previous studies demonstrated that they can possess insulating, semiconducting or metallic properties here we report that polymers can also be semi-metallic. Semi-metals, exemplified by bismuth, graphite and telluride alloys, have no energy bandgap and a very low density of states at the Fermi level. Furthermore, they typically have a higher Seebeck coefficient and lower thermal conductivities compared with metals, thus being suitable for thermoelectric applications. We measure the thermoelectric properties of various poly(3,4-ethylenedioxythiophene) s les, and observe a marked increase in the Seebeck coefficient when the electrical conductivity is enhanced through molecular organization. This initiates the transition from a Fermi glass to a semi-metal. The high Seebeck value, the metallic conductivity at room temperature and the absence of unpaired electron spins makes polymer semi-metals attractive for thermoelectrics and spintronics.
Publisher: Springer Science and Business Media LLC
Date: 05-07-2009
DOI: 10.1038/NMAT2494
Abstract: Significant advances have been made in the understanding of the pathophysiology, molecular targets and therapies for the treatment of a variety of nervous-system disorders. Particular therapies involve electrical sensing and stimulation of neural activity, and significant effort has therefore been devoted to the refinement of neural electrodes. However, direct electrical interfacing suffers from some inherent problems, such as the inability to discriminate amongst cell types. Thus, there is a need for novel devices to specifically interface nerve cells. Here, we demonstrate an organic electronic device capable of precisely delivering neurotransmitters in vitro and in vivo. In converting electronic addressing into delivery of neurotransmitters, the device mimics the nerve synapse. Using the peripheral auditory system, we show that out of a erse population of cells, the device can selectively stimulate nerve cells responding to a specific neurotransmitter. This is achieved by precise electronic control of electrophoretic migration through a polymer film. This mechanism provides several sought-after features for regulation of cell signalling: exact dosage determination through electrochemical relationships, minimally disruptive delivery due to lack of fluid flow, and on-off switching. This technology has great potential as a therapeutic platform and could help accelerate the development of therapeutic strategies for nervous-system disorders.
Publisher: Elsevier BV
Date: 11-2004
Publisher: Wiley
Date: 16-07-2013
Publisher: AIP Publishing
Date: 20-04-2004
DOI: 10.1063/1.1737064
Abstract: We report photo- and electroluminescence from an alternating conjugated polymer consisting of fluorene units and low-band gap donor-acceptor-donor (D–A–D) units. The D–A–D segment includes two electron-donating thiophene rings combined with a thiadiazolo-quinoxaline unit, which is electron withdrawing to its nature. The resulting polymer is conjugated and has a band gap of 1.27 eV. The corresponding electro- and photoluminescence spectra both peak at approximately 1 μm. Light-emitting diodes, based on a single layer of the polymer, demonstrated external quantum efficiencies from 0.03% to 0.05%.
Publisher: Wiley
Date: 28-01-2016
Publisher: Springer Science and Business Media LLC
Date: 21-05-2014
DOI: 10.1038/NMAT3981
Publisher: Wiley
Date: 04-11-2011
Abstract: Let it grow: The conjugated polymer poly(3,4-ethylenedioxythiophene) (PEDOT) was synthesized with heparin as the counterion to form a cell culture substrate. The surface of PEDOT:heparin in the neutral state associated biologically active growth factors. Electrochemical in situ oxidation of PEDOT during live cell culture decreased the bioavailability of the growth factor and created an exact onset of neural stem cell differentiation.
Publisher: American Chemical Society (ACS)
Date: 10-1994
DOI: 10.1021/MA00100A039
Publisher: Wiley
Date: 25-04-2016
Abstract: Bones have been shown to exhibit piezoelectric properties, generating electrical potential upon mechanical deformation and responding to electrical stimulation with the generation of mechanical stress. Thus, the effects of electrical stimulation on bone tissue engineering have been extensively studied. However, in bone regeneration applications, only few studies have focused on the use of electroactive 3D biodegradable scaffolds at the interphase with stem cells. Here a method is described to combine the bone regeneration capabilities of 3D‐printed macroporous medical grade polycaprolactone (PCL) scaffolds with the electrical and electrochemical capabilities of the conducting polymer poly(3,4‐ethylenedioxythiophene) (PEDOT). PCL scaffolds have been highly effective in vivo as bone regeneration grafts, and PEDOT is a leading material in the field of organic bioelectronics, due to its stability, conformability, and biocompatibility. A protocol is reported for scaffolds functionalization with PEDOT, using vapor‐phase polymerization, resulting in a conformal conducting layer. Scaffolds' porosity and mechanical stability, important for in vivo bone regeneration applications, are retained. Human fetal mesenchymal stem cells proliferation is assessed on the functionalized scaffolds, showing the cytocompatibility of the polymeric coating. Altogether, these results show the feasibility of the proposed approach to obtain electroactive scaffolds for electrical stimulation of stem cells for regenerative medicine.
Publisher: Wiley
Date: 27-10-2016
Abstract: Ladder-type "torsion-free" conducting polymers (e.g., polybenzimidazobenzophenanthroline (BBL)) can outperform "structurally distorted" donor-acceptor polymers (e.g., P(NDI2OD-T2)), in terms of conductivity and thermoelectric power factor. The polaron delocalization length is larger in BBL than in P(NDI2OD-T2), resulting in a higher measured polaron mobility. Structure-function relationships are drawn, setting material-design guidelines for the next generation of conducting thermoelectric polymers.
Publisher: Elsevier BV
Date: 06-2012
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C1LC20436J
Abstract: The importance of mechanotransduction for physiological systems is becoming increasingly recognized. The effect of mechanical stimulation is well studied in organs and tissues, for instance by using flexible tissue culture substrates that can be stretched by external means. However, on the cellular and subcellular level, dedicated technology to apply appropriate mechanical stimuli is limited. Here we report an organic electronic microactuator chip for mechanical stimulation of single cells. These chips are manufactured on silicon wafers using traditional microfabrication and photolithography techniques. The active unit of the chip consists of the electroactive polymer polypyrrole that expands upon the application of a low potential. The fact that polypyrrole can be activated in physiological electrolytes makes it well suited as the active material in a microactuator chip for biomedical applications. Renal epithelial cells, which are responsive to mechanical stimuli and relevant from a physiological perspective, are cultured on top of the microactuator chip. The cells exhibit good adhesion and spread along the surface of the chip. After culturing, in idual cells are mechanically stimulated by electrical addressing of the microactuator chip and the response to this stimulation is monitored as an increase in intracellular Ca(2+). This Ca(2+) response is caused by an autocrine ATP signalling pathway associated with mechanical stimulation of the cells. In conclusion, the present work demonstrates a microactuator chip based on an organic conjugated polymer, for mechanical stimulation of biological systems at the cellular and sub-cellular level.
Publisher: Wiley
Date: 23-08-2011
Publisher: Wiley
Date: 1119
Publisher: Elsevier BV
Date: 10-2009
DOI: 10.1016/J.BIOMATERIALS.2009.07.059
Abstract: Conducting polymers are soft, flexible materials, exhibiting material properties that can be reversibly changed by electrochemically altering the redox state. Surface chemistry is an important determinant for the molecular events of cell adhesion. Therefore, we analyzed whether the redox state of the conducting polymer PEDOT:Tosylate can be used to control epithelial cell adhesion and proliferation. A functionalized cell culture dish comprising two adjacent electrode surfaces was developed. Upon electronic addressing, reduced and oxidized surfaces are created within the same device. Simultaneous analysis of how a homogenous epithelial MDCK cell population responded to the electrodes revealed distinct surface-specific differences. Presentation of functional fibronectin on the reduced electrode promoted focal adhesion formation, involving alpha(v)beta(3) integrin, cell proliferation, and ensuing formation of polarized monolayers. In contrast, the oxidized surface harbored only few cells with deranged morphology showing no indication of proliferation. This stems from the altered fibronectin conformation, induced by the different surface chemistry of the PEDOT:Tosylate electrode in the oxidized state. Our results demonstrate a novel use of PEDOT:Tosylate as a cell-hosting material in multiple-electrode systems, where cell adhesion and proliferation can be controlled by electrochemical modulation of surface properties.
Publisher: Royal Society of Chemistry (RSC)
Date: 24-06-2014
DOI: 10.1039/C4LC00201F
Abstract: We hereby report a method to fabricate addressable micropatterns of e-surfaces based on the conducting polymer poly(3,4-ethylenedioxythiophene) doped with the anion tosylate (PEDOT:Tos) to gain dynamic control over the spatial distribution of platelets in vitro. With thin film processing and microfabrication techniques, patterns down to 10 μm were produced to enable active regulation of platelet adhesion at high spatial resolution. Upon electronic addressing, both reduced and oxidized surfaces were created within the same device. This surface modulation dictates the conformation and/or orientation, rather than the concentration, of surface proteins, thus indirectly regulating the adhesion of platelets. The reduced electrode supported platelet adhesion, whereas the oxidized counterpart inhibited adhesion. PEDOT:Tos electrode fabrication is compatible with most of the classical patterning techniques used in printing as well as in the electronics industry. The first types of tools promise ultra-low-cost production of low-resolution (>30 μm) electrode patterns that may combine with traditional substrates and dishes used in a classical analysis setup. Platelets play a pronounced role in cardiovascular diseases and have become an important drug target in order to prevent thrombosis. This clinical path has in turn generated a need for platelet function tests to monitor and assess platelet drug efficacy. The spatial control of platelet adherence presented here could prove valuable for blood cell separation or biosensor microarrays, e.g. in diagnostic applications where platelet function is evaluated.
Publisher: Elsevier BV
Date: 05-1998
Publisher: American Chemical Society (ACS)
Date: 21-11-2008
DOI: 10.1021/LA8028337
Abstract: Adhesion is an essential parameter for stem cells. It regulates the overall cell density along the carrying surface, which further dictates the differentiation scheme of stem cells toward a more matured and specified population as well as tissue. Electronic control of the seeding density of neural stem cells (c17.2) is here reported. Thin electrode films of poly(3,4-ethylenedioxythiophene) (PEDOT):Tosylate were manufactured along the floor of cell growth dishes. As the oxidation state of the conjugated polymer electrodes was controlled, the seeding density could be varied by a factor of 2. Along the oxidized PEDOT:Tosylate-electrodes, a relatively lower density of, and less tightly bonded, human serum albumin (HSA) was observed as compared to reduced electrodes. We found that this favors adhesion of the specific stem cells studied. Surface analysis experiments, such as photoelectron spectroscopy, and water contact angle measurements, were carried out to investigate the mechanisms responsible for the electronic control of the seeding density of the c17.2 neural stem cells. Further, our findings may provide an opening for electronic control of stem cell differentiation.
Publisher: Elsevier BV
Date: 03-1997
Publisher: Wiley
Date: 10-2021
Abstract: Organic electrochemical transistors (OECTs) have the potential to revolutionize the field of organic bioelectronics. To date, most of the reported OECTs include p‐type (semi‐)conducting polymers as the channel material, while n‐type OECTs are yet at an early stage of development, with the best performing electron‐transporting materials still suffering from low transconductance, low electron mobility, and slow response time. Here, the high electrical conductivity of multi‐walled carbon nanotubes (MWCNTs) and the large volumetric capacitance of the ladder‐type π‐conjugated redox polymer poly(benzimidazobenzophenanthroline) (BBL) are leveraged to develop n‐type OECTs with record‐high performance. It is demonstrated that the use of MWCNTs enhances the electron mobility by more than one order of magnitude, yielding fast transistor transient response (down to 15 ms) and high μC * (electron mobility × volumetric capacitance) of about 1 F cm −1 V −1 s −1 . This enables the development of complementary inverters with a voltage gain of and a large worst‐case noise margin at a supply voltage of .6 V, while consuming less than 1 µW of power.
Publisher: Elsevier BV
Date: 11-2009
Publisher: Wiley
Date: 20-11-2009
Abstract: Complex patterning of the extracellular matrix, cells, and tissues under in situ electronic control is the aim of the technique presented here. The distribution of epithelial cells along the channel of an organic electrochemical transistor is shown to be actively controlled by the gate and drain voltages, as electrochemical gradients are formed along the transistor channel when the device is biased..
Publisher: SPIE
Date: 24-03-2011
DOI: 10.1117/12.880277
Publisher: Wiley
Date: 03-08-2016
Publisher: Public Library of Science (PLoS)
Date: 11-04-2011
Publisher: Wiley
Date: 26-11-2009
Publisher: Wiley
Date: 06-1994
Publisher: Elsevier BV
Date: 03-1997
Publisher: Elsevier BV
Date: 03-1997
Publisher: Elsevier BV
Date: 12-2006
No related grants have been discovered for Magnus Berggren.