ORCID Profile
0000-0002-9728-7399
Current Organisations
Pendar Technologies, LLC
,
Eos Photonics
,
Duke-NUS Medical School
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: AIP Publishing
Date: 26-11-2012
DOI: 10.1063/1.4767646
Abstract: We show that perfect absorption can be achieved in a system comprising a single lossy dielectric layer of thickness much smaller than the incident wavelength on an opaque substrate by utilizing the nontrivial phase shifts at interfaces between lossy media. This design is implemented with an ultra-thin (∼λ/65) vanadium dioxide (VO2) layer on sapphire, temperature tuned in the vicinity of the VO2 insulator-to-metal phase transition, leading to 99.75% absorption at λ = 11.6 μm. The structural simplicity and large tuning range (from ∼80% to 0.25% in reflectivity) are promising for thermal emitters, modulators, and bolometers.
Publisher: IOP Publishing
Date: 27-05-2011
Publisher: American Chemical Society (ACS)
Date: 03-11-2010
DOI: 10.1021/NL102747V
Abstract: Enhancing nonlinear processes at the nanoscale is a crucial step toward the development of nanophotonics and new spectroscopy techniques. Here we demonstrate a novel plasmonic structure, called plasmonic nanocavity grating, which is shown to dramatically enhance surface nonlinear optical processes. It consists of resonant cavities that are periodically arranged to combine local and grating resonances. The four-wave mixing signal generated in our gold nanocavity grating is enhanced by a factor up to ≈2000, 2 orders of magnitude higher than that previously reported.
Publisher: Informa UK Limited
Date: 2022
DOI: 10.2147/JAA.S328653
Publisher: Elsevier BV
Date: 04-2021
Publisher: Elsevier BV
Date: 09-2021
DOI: 10.1016/J.CHEST.2021.04.013
Abstract: Phenotypic characteristics of patients with eosinophilic and noneosinophilic asthma are not well characterized in global, real-life severe asthma cohorts. What is the prevalence of eosinophilic and noneosinophilic phenotypes in the population with severe asthma, and can these phenotypes be differentiated by clinical and biomarker variables? This was an historical registry study. Adult patients with severe asthma and available blood eosinophil count (BEC) from 11 countries enrolled in the International Severe Asthma Registry (January 1, 2015-September 30, 2019) were categorized according to likelihood of eosinophilic phenotype using a predefined gradient eosinophilic algorithm based on highest BEC, long-term oral corticosteroid use, elevated fractional exhaled nitric oxide, nasal polyps, and adult-onset asthma. Demographic and clinical characteristics were defined at baseline (ie, 1 year before or closest to date of BEC). One thousand seven hundred sixteen patients with prospective data were included 83.8% were identified as most likely (grade 3), 8.3% were identified as likely (grade 2), and 6.3% identified as least likely (grade 1) to have an eosinophilic phenotype, and 1.6% of patients showed a noneosinophilic phenotype (grade 0). Eosinophilic phenotype patients (ie, grades 2 or 3) showed later asthma onset (29.1 years vs 6.7 years P < .001) and worse lung function (postbronchodilator % predicted FEV According to this multicomponent, consensus-driven, and evidence-based eosinophil gradient algorithm (using variables readily accessible in real life), the severe asthma eosinophilic phenotype was more prevalent than previously identified and was phenotypically distinct. This pragmatic gradient algorithm uses variables readily accessible in primary and specialist care, addressing inherent issues of phenotype heterogeneity and phenotype instability. Identification of treatable traits across phenotypes should improve therapeutic precision.
Publisher: The Optical Society
Date: 24-10-2011
DOI: 10.1364/OE.19.022113
Publisher: Elsevier BV
Date: 05-2022
DOI: 10.1016/J.JAIP.2021.12.027
Abstract: Regulatory bodies have approved five biologics for severe asthma. However, regional differences in accessibility may limit the global potential for personalized medicine. To compare global differences in ease of access to biologics. In April 2021, national prescription criteria for omalizumab, mepolizumab, reslizumab, benralizumab, and dupilumab were reviewed by severe asthma experts collaborating in the International Severe Asthma Registry. Outcomes (per country, per biologic) were (1) country-specific prescription criteria and (2) development of the Biologic Accessibility Score (BACS). The BACS composite score incorporates 10 prescription criteria, each with a maximum score of 10 points. Referenced to European Medicines Agency marketing authorization specifications, a higher score reflects easier access. Biologic prescription criteria differed substantially across 28 countries from five continents. Blood eosinophil count thresholds (usually ≥300 cells/μL) and exacerbations were key requirements for anti-IgE/anti-IL-5/5R prescriptions in around 80% of licensed countries. Most countries (40% for dupilumab to 54% for mepolizumab) require two or more moderate or severe exacerbations, whereas numbers ranged from none to four. Moreover, 0% (for reslizumab) to 21% (for omalizumab) of countries required long-term oral corticosteroid use. The BACS highlighted marked between-country differences in ease of access. For omalizumab, mepolizumab, benralizumab, and dupilumab, only two, one, four, and seven countries, respectively, scored equal or higher than the European Medicines Agency reference BACS. For reslizumab, all countries scored lower. Although some differences were expected in country-specific biologic prescription criteria and ease of access, the substantial differences found in the current study present a challenge to implementing precision medicine across the world.
Publisher: Elsevier BV
Date: 04-2020
DOI: 10.1016/J.CHEST.2019.10.051
Abstract: Regional and/or national severe asthma registries provide valuable country-specific information. However, they are often limited in scope within the broader definitions of severe asthma, have insufficient statistical power to answer many research questions, lack intraoperability to share lessons learned, and have fundamental differences in data collected, making cross comparisons difficult. What is missing is a worldwide registry which brings all severe asthma data together in a cohesive way, under a single umbrella, based on standardized data collection protocols, permitting data to be shared seamlessly. The International Severe Asthma Registry (ISAR isaregistries.org/) is the first global adult severe asthma registry. It is a joint initiative where national registries (both newly created and preexisting) retain ownership of their own data but open their borders and share data with ISAR for ethically approved research purposes. Its strength comes from collection of patient-level, anonymous, longitudinal, real-life, standardized, high-quality data (using a core set of variables) from countries across the world, combined with organizational structure, database experience, inclusivity/openness, and clinical, academic, and database expertise. This gives ISAR sufficient statistical power to answer important research questions, sufficient data standardization to compare across countries and regions, and the structure and expertise necessary to ensure its continuance and the scientific integrity and clinical applicability of its research. ISAR offers a unique opportunity to implement existing knowledge, generate new knowledge, and identify the unknown, therefore promoting new research. The aim of this commentary is to fully describe how ISAR may improve our understanding of severe asthma.
Publisher: Springer Science and Business Media LLC
Date: 14-08-2020
DOI: 10.1186/S12874-020-01065-0
Abstract: Severe asthma exerts a disproportionately heavy burden on patients and health care. Due to the heterogeneity of the severe asthma population, many patients need to be evaluated to understand the clinical features and outcomes of severe asthma in order to facilitate personalised and targeted care. The International Severe Asthma Registry (ISAR) is a multi-country registry project initiated to aid in this endeavour. ISAR is a multi-disciplinary initiative benefitting from the combined experience of the ISAR Steering Committee (ISC comprising 47 clinicians and researchers across 29 countries, who have a special interest and/or experience in severe asthma management or establishment and maintenance of severe asthma registries) in collaboration with scientists and experts in database management and communication. Patients (≥18 years old) receiving treatment according to the 2018 definitions of the Global Initiative for Asthma (GINA) Step 5 or uncontrolled on GINA Step 4 treatment will be included. Data will be collected on a core set of 95 variables identified using the Delphi method. Participating registries will agree to provide access to and share standardised anonymous patient-level data with ISAR. ISAR is a registered data source on the European Network of Centres for Pharmacoepidemiology and Pharmacovigilance. ISAR’s collaborators include Optimum Patient Care, the Respiratory Effectiveness Group (REG) and AstraZeneca. ISAR is overseen by the ISC, REG, the Anonymised Data Ethics & Protocol Transparency Committee and the ISAR operational committee, ensuring the conduct of ethical, clinically relevant research that brings value to all key stakeholders. ISAR aims to offer a rich source of real-life data for scientific research to understand and improve disease burden, treatment patterns and patient outcomes in severe asthma. Furthermore, the registry will provide an international platform for research collaboration in respiratory medicine, with the overarching aim of improving primary and secondary care of adults with severe asthma globally.
Publisher: Elsevier BV
Date: 04-2020
DOI: 10.1016/J.CHEST.2019.10.053
Abstract: Clinical characteristics of the international population with severe asthma are unknown. Intercountry comparisons are hindered by variable data collection within regional and national severe asthma registries. We aimed to describe demographic and clinical characteristics of patients treated in severe asthma services in the United States, Europe, and the Asia-Pacific region. The International Severe Asthma Registry retrospectively and prospectively collected data in patients with severe asthma (≥ 18 years old), receiving Global Initiative for Asthma (GINA) Step 5 treatment or with severe asthma remaining uncontrolled at GINA Step 4. Baseline demographic and clinical data were collected from the United States, United Kingdom, South Korea, Italy, and the Severe Asthma Web-based Database registry (including Australia, Singapore, and New Zealand) from December 2014 to December 2017. We included 4,990 patients. Mean (SD) age was 55.0 (15.9) years, and mean (SD) age at asthma onset was 30.7 (17.7) years. Patients were predominantly female (59.3%) and white (72.6%), had never smoked (60.5%), and were overweight or obese (70.4%) 34.9% were at GINA Step 5 and 57.2% had poorly controlled disease. A total of 51.1% of patients were receiving regular intermittent oral corticosteroids, and 25.4% were receiving biologics (72.6% for those at GINA Step 5). Mean (SD) exacerbation rate was 1.7 (2.7) per year. Intercountry variation was observed in clinical characteristics, prescribed treatments, and biomarker profiles. Using a common data set and definitions, this study describes severe asthma characteristics of a large patient cohort included in multiple severe asthma registries and identifies country differences. Whether these are related to underlying epidemiological factors, environmental factors, phenotypes, asthma management systems, treatment access, and/or cultural factors requires further study.
Publisher: The Optical Society
Date: 11-10-2011
DOI: 10.1364/AO.50.000G56
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 05-2013
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Isha Chaudhry.