514 results on '"Christopher Chang"'
Search Results
102. Drug desensitization
- Author
-
Lourdes Ramirez, Faina Shenderov, and Christopher Chang
- Published
- 2022
103. Oral food challenges
- Author
-
Christopher Chang, Nicole Akar-Ghibril, and Kathleen Hathaway
- Published
- 2022
104. Introduction
- Author
-
Christopher Chang
- Published
- 2022
105. A brief history of allergy and immunology
- Author
-
Kranthi Nomula, Kyndra Liburd, Xiang Ge, JinLyu Sun, and Christopher Chang
- Published
- 2022
106. Basic immunology
- Author
-
Christopher Chang
- Published
- 2022
107. An evolved AAV variant enables efficient genetic engineering of murine T cells
- Author
-
William A. Nyberg, Jonathan Ark, Angela To, Sylvanie Clouden, Gabriella Reeder, Joseph J. Muldoon, Jing-Yi Chung, William H. Xie, Vincent Allain, Zachary Steinhart, Christopher Chang, Alexis Talbot, Sandy Kim, Alan Rosales, L. Patrick Havlik, Harold Pimentel, Aravind Asokan, and Justin Eyquem
- Subjects
General Biochemistry, Genetics and Molecular Biology - Published
- 2023
108. Thermal WIMPs and the scale of new physics: global fits of Dirac dark matter effective field theories
- Author
-
Tomás E. Gonzalo, Janina J. Renk, Martin White, Sebastian Wild, Joachim Brod, Andrew Fowlie, Pat Scott, Christopher Chang, Ben Farmer, Felix Kahlhoefer, Will Handley, Jure Zupan, Farvah Mahmoudi, Neal Avis Kozar, Jonathan M. Cornell, Are Raklev, Torsten Bringmann, Ankit Beniwal, Patrick Stöcker, Sanjay Bloor, Csaba Balázs, Peter Athron, Anders Kvellestad, Andre Scaffidi, Aaron C. Vincent, M. T. Prim, Beniwal, Ankit [0000-0003-4849-0611], Apollo - University of Cambridge Repository, Institut de Physique des 2 Infinis de Lyon (IP2I Lyon), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), GAMBIT, and Beniwal, A [0000-0003-4849-0611]
- Subjects
Top quark ,Physics and Astronomy (miscellaneous) ,scattering [dark matter] ,Physics beyond the Standard Model ,single production [jet] ,dimension: 7 ,QC770-798 ,mass [dark matter] ,Astrophysics ,01 natural sciences ,WIMP: dark matter ,dark matter [WIMP] ,nonrelativistic [effective field theory] ,High Energy Physics - Phenomenology (hep-ph) ,scale: new physics ,Effective field theory ,7 [dimension] ,new physics [scale] ,Physics ,effective field theory: nonrelativistic ,Dirac [fermion] ,halo [dark matter] ,hep-ph ,jet: single production ,ATLAS ,QB460-466 ,dark matter: scattering ,High Energy Physics - Phenomenology ,mass [top] ,symbols ,astro-ph.CO ,relic density [dark matter] ,renormalization group ,Regular Article - Theoretical Physics ,Astrophysics - Cosmology and Nongalactic Astrophysics ,Quark ,Particle physics ,Astrophysics and Astronomy ,Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,satellite: Planck ,interpretation of experiments: CERN LHC Coll ,nucleus: form factor ,Dark matter ,top: mass ,FOS: Physical sciences ,Standard Model ,quark ,symbols.namesake ,dark matter: halo ,Nuclear and particle physics. Atomic energy. Radioactivity ,0103 physical sciences ,ddc:530 ,Planck ,010306 general physics ,Engineering (miscellaneous) ,Particle Physics - Phenomenology ,010308 nuclear & particles physics ,dark matter: relic density ,dark matter: mass ,form factor [nucleus] ,Dark matter halo ,[PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph] ,CERN LHC Coll [interpretation of experiments] ,fermion: Dirac ,[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] ,Planck [satellite] ,experimental results - Abstract
The European physical journal / C 81(11), 992 (2021). doi:10.1140/epjc/s10052-021-09712-6, We assess the status of a wide class of WIMP dark matter (DM) models in light of the latest experimental results using the global fitting framework GAMBIT. We perform a global analysis of effective field theory (EFT) operators describing the interactions between a gauge-singlet Dirac fermion and the Standard Model quarks, the gluons and the photon. In this bottom-up approach, we simultaneously vary the coefficients of 14 such operators up to dimension 7, along with the DM mass, the scale of new physics and several nuisance parameters. Our likelihood functions include the latest data from Planck, direct and indirect detection experiments, and the LHC. For DM masses below 100 GeV, we find that it is impossible to satisfy all constraints simultaneously while maintaining EFT validity at LHC energies. For new physics scales around 1 TeV, our results are influenced by several small excesses in the LHC data and depend on the prescription that we adopt to ensure EFT validity. Furthermore, we find large regions of viable parameter space where the EFT is valid and the relic density can be reproduced, implying that WIMPs can still account for the DM of the universe while being consistent with the latest data., Published by Springer, Heidelberg
- Published
- 2021
109. Hot-charge relaxation in lead halide perovskite: uncovering the bandgap dynamics, hot-biexciton effect and photo-bleaching shift
- Author
-
Fan, Kezhou, primary, Chan, Christopher Chang Sing, additional, Yuan, Ligang, additional, Yan, Keyou, additional, and Wong, Kam Sing, additional
- Published
- 2022
- Full Text
- View/download PDF
110. Long-Term Effects of COVID-19
- Author
-
Shreeya Joshee, Nikhil Vatti, and Christopher Chang
- Subjects
holistic ,MIS-C, Multi system inflammatory syndrome in children ,Lung Diseases ,6MWT, 6-minute walk test ,VTE, venous thromboembolism events ,review ,COVID-19 ,General Medicine ,clinical guidelines ,KD, Kawasaki Disease ,Cardiovascular Diseases ,ICU, Intensive Care Unit ,Post-acute COVID-19 ,MIS-A, Multi system inflammatory syndrome in adults ,systems ,Humans ,IL, Interleukin ,Nervous System Diseases - Abstract
Coronavirus disease 2019 (COVID-19) is the third deadly coronavirus infection of the 21st century that has proven to be significantly more lethal than its predecessors, with the number of infected patients and deaths still increasing daily. From December 2019 to July 2021, this virus has infected nearly 200 million people and led to more than 4 million deaths. Our understanding of COVID-19 is constantly progressing, giving better insight into the heterogeneous nature of its acute and long-term effects. Recent literature on the long-term health consequences of COVID-19 discusses the need for a comprehensive understanding of the multisystemic pathophysiology, clinical predictors, and epidemiology to develop and inform an evidence-based, multidisciplinary management approach. A PubMed search was completed using variations on the term post-acute COVID-19. Only peer-reviewed studies in English published by July 17, 2021 were considered for inclusion. All studies discussed in this text are from adult populations unless specified (as with multisystem inflammatory syndrome in children). The preliminary evidence on the pulmonary, cardiovascular, neurological, hematological, multisystem inflammatory, renal, endocrine, gastrointestinal, and integumentary sequelae show that COVID-19 continues after acute infection. Interdisciplinary monitoring with holistic management that considers nutrition, physical therapy, psychological management, meditation, and mindfulness in addition to medication will allow for the early detection of post-acute COVID-19 sequelae symptoms and prevent long-term systemic damage. This review serves as a guideline for effective management based on current evidence, but clinicians should modify recommendations to reflect each patient's unique needs and the most up-to-date evidence. The presence of long-term effects presents another reason for vaccination against COVID-19.
- Published
- 2021
111. S3000 Ezetimibe-Induced Autoimmune Hepatitis: An Uncommon Offender
- Author
-
Anthony P. Nguyen, Yiting Li, Eyerusalem Akpan, and Christopher Chang
- Subjects
Hepatology ,Gastroenterology - Published
- 2022
112. Profiling the proteome-wide selectivity of diverse electrophiles
- Author
-
Stephan M. Hacker, Alexey I. Nesvizhskii, F. Dean Toste, Kathrin Lang, Christopher Chang, Marko Cigler, Thomas E. Maher, Patrick Raunft, Dario Mrdović, Kristina Krauskopf, Michael Zollo, Lisa Lewald, Patricia Musacchio, Fengchao Yu, and Patrick R. A. Zanon
- Abstract
Targeted covalent inhibitors are powerful entities in drug discovery, but their application has so far mainly been limited to addressing cysteine residues. The development of cysteine-directed covalent inhibitors has largely profited from determining their proteome-wide selectivity using competitive residue-specific proteomics. Several probes have recently been described to monitor other amino acids using this technology and many more electrophiles exist to modify proteins. Nevertheless, a direct, proteome‑wide comparison of the selectivity of diverse probes is still entirely missing. Here, we developed a completely unbiased workflow to analyse electrophile selectivity proteome‑wide and applied it to directly compare 54 alkyne probes containing diverse reactive groups. In this way, we verified and newly identified probes to monitor a total of nine different amino acids as well as the N‑terminus proteome‑wide. This selection includes the first probes to globally monitor tryptophans, histidines and arginines as well as novel tailored probes for methionines, aspartates and glutamates.
- Published
- 2021
113. Chemical composition of smoke produced by open versus laparoscopic surgery for cholecystectomy
- Author
-
Francis Li-Tien Hsu, Te-Wei Ho, Christopher Chang, Jin-Ming Wu, and Ming-Tsan Lin
- Subjects
Hepatology ,Cholecystectomy, Laparoscopic ,Smoke ,Gastroenterology ,Humans ,Cholecystectomy ,Laparoscopy ,Gallbladder Diseases - Abstract
Smoke produced by traditional open surgery (TOS) has long been considered hazardous to medical staff. Compared with TOS, minimally invasive surgery under carbon dioxide pneumoperitoneum is associated with a faster recovery and less wound pain. However, the impact of oxygen-deficient environment on the chemical contents of smoke has not been comprehensively assessed.This research evaluated the chemical composition and volatile organic compound (TVOC) level in smoke produced by open cholecystectomy (OC) versus laparoscopic cholecystectomy (LC) for gallbladder diseases. Smoke samples were collected and analyzed via gas chromatography-mass spectrometry. Chemical compounds were further grouped according to molecular weight and toxicity.Compared with the OC, LC had significantly higher halocarbon and TVOC levels but lower cycloalkene and aldehyde levels. No halocarbons were isolated from OC specimens. When stratified based on molecular weight, LC had a bimodal pattern (i.e., high levels of small-sized [60 Da] and large-sized [120 Da] compounds). There was no difference in terms of toxicity types, incidence, and severity associated with detected compounds between two groups.LC is associated with a higher TVOC level and proportion of low- and high-molecular-weight organic compounds. Further strategies of evacuating these health hazards and preventing smoke leakage through trocars should be considered.
- Published
- 2021
114. Bee Venom Allergy in Chinese Beekeepers and Patients Under Live Bee Apitherapy
- Author
-
Yi Li, Wan-Yao Li, Li-Sha Li, Sai-Nan Bian, Zi Xi Wang, Kai Guan, Ying-Yang Xu, Le Cui, Christopher Chang, Bobby Quentin Lanier, and Qiao-Ju Han
- Subjects
Apitherapy ,Allergy ,Traditional medicine ,Bee venom ,business.industry ,medicine ,medicine.disease ,business - Abstract
Background: Hymenoptera stings are one of the common causes of anaphylaxis. The prevalence of systemic allergic reactions seems to be higher in highly exposed populations such as beekeepers and individuals receiving live bee acupuncture (LBA). However, there are a very few of studies on venom allergy in these populations. We performed two observational studies to describe the characteristics and risk factors of venom allergy in beekeepers and the LBA population.Methods: A total of 99 beekeepers and 127 individuals receiving live bee acupuncture were interviewed. Skin prick tests were performed on subjects with suspected bee venom allergy.Results: The prevalence of bee venom allergy was 34.3% among beekeepers and 29.0% in the LBA population. Systemic reactions occurred in 11.3% of the LBA population, and 28.3% of beekeepers. For beekeepers with exposure to 2-4 stings per year and ≥5 stings per year, the risk for developing venom allergy increased to 6.745-fold (95% CI 2.139-21.266) and 42.297-fold (95% CI 7.060-253.399) respectively, compared to the ≤1 sting per year group. Conversely, in the LBA population, compared to frequency ≤2 LBA stings per week, the adjusted OR of venom allergy was 0.281 (95% CI 0.075-1.047) and 0.166 (95% CI 0.045-0.612) for frequency 3-6 LBA stings per week and ≥7 stings per week respectively. The knowledge of adrenaline and venom immunotherapy was limited in both beekeepers and traditional doctors.Conclusion: The frequency of stings with high risk for bee venom allergy was >4/year in beekeepers and
- Published
- 2021
115. Complex regional pain syndrome – False hopes and miscommunications
- Author
-
Christopher Chang, M. Eric Gershwin, and Patrick McDonnell
- Subjects
0301 basic medicine ,medicine.medical_specialty ,Sympathetic nervous system ,Immunology ,Analgesic ,03 medical and health sciences ,0302 clinical medicine ,Fibromyalgia ,medicine ,Animals ,Humans ,Immunology and Allergy ,Ketamine ,Intensive care medicine ,030203 arthritis & rheumatology ,business.industry ,Chronic pain ,medicine.disease ,030104 developmental biology ,medicine.anatomical_structure ,Complex regional pain syndrome ,Opioid ,Neuropathic pain ,business ,Complex Regional Pain Syndromes ,medicine.drug - Abstract
Complex regional pain syndrome (CRPS) has been considered to be an autoimmune disease and there have been clinical trials with intravenous immunoglobulin. Often the etiology of the so-called CRPS diagnosis cannot be discerned and there are no validated instruments that provide functional metrics. The term complex regional pain syndrome (CRPS), coined in 1994 to describe patients in whom the pain is out of proportion to the injury, was actually a diagnosis proposed during the American Civil War, but was originally known as causalgia. Physicians have long observed similar sensitivity and inflammatory symptoms following periods of immobilization and disuse, which generally resolve within a few months of remobilization. Following the original description, persistent disproportionate pain would come to be known under many other names until researchers theorized that it was related to dysfunction in the sympathetic nervous system, after which it acquired the moniker, Reflex Sympathetic Dystrophy ("RSD"). In the latter quarter of the twentieth century, after researchers failed to prove the connection between the pain and the sympathetic nervous system, a small cadre of physicians-without rigorous science-invented CRPS. This new descriptor, CRPS, has become not only a diagnosis without objective data but with proposed criteria involving ambiguous signs and symptoms with low specificity. It has led to patients being treated erroneously with sympatholytic drugs, with or without pharmaceutical or surgical blockade of the sympathetic nervous system, unwarranted use of ketamine infusions, inappropriate use of narcotics and nerve stimulation. Intravenous immunoglobulin infusions have not been effective in the treatment of chronic pain. The indiscriminate use of pain medications to treat subjective symptoms of unclear diagnoses can be a risk factor for opioid and analgesic misuse or abuse.
- Published
- 2019
116. HCC You Cannot See
- Author
-
Vaishnavi, Boppana, Sakshi, Sahni, Joseph, Glass, Christopher, Chang, and Denis M, McCarthy
- Subjects
Liver Cirrhosis ,Male ,Carcinoma, Hepatocellular ,Liver Neoplasms ,Humans ,Middle Aged - Published
- 2021
117. Targeted Therapies for Multiple Myeloma
- Author
-
Michael Sze Yuan Low and Christopher Chang-Yew Leow
- Subjects
medicine.drug_class ,Druggability ,Medicine (miscellaneous) ,Review ,Monoclonal antibody ,therapeutic targets ,03 medical and health sciences ,XPO1 ,0302 clinical medicine ,Medicine ,Epigenetics ,Multiple myeloma ,030304 developmental biology ,0303 health sciences ,business.industry ,SLAMF7 ,medicine.disease ,multiple myeloma ,Proteasome ,monoclonal antibody ,030220 oncology & carcinogenesis ,Cancer research ,Histone deacetylase ,business - Abstract
Multiple myeloma continues to be a challenging disorder to treat despite improved therapies and the widespread use of proteasome inhibitors and immunomodulatory drugs. Although patient outcomes have improved, the disease continues to invariably relapse, and in the majority of cases, a cure remains elusive. In the last decade, there has been an explosion of novel drugs targeting cellular proteins essential for malignant plasma cell proliferation and survival. In this review, we focus on novel druggable targets leading to the development of monoclonal antibodies and cellular therapies against surface antigens (CD38, CD47, CD138, BCMA, SLAMF7, GPRC5D, FcRH5), inhibitors of epigenetic regulators such as histone deacetylase (HDAC), and agents targeting anti-apoptotic (BCL-2), ribosomal (eEF1A2) and nuclear export (XPO1) proteins.
- Published
- 2021
118. A Supramolecular Porous Organic Cage Platform Promotes Electrochemical Hydrogen Evolution from Water Catalyzed by Cobalt Porphyrins
- Author
-
Christopher Chang, Kimoon Kim, Younghoon Kim, Lun An, Bahiru Punja Benke, and Peter T. Smith
- Abstract
We report a supramolecular porous organic cage platform composed of cobalt porphyrins for catalyzing the electrochemical hydrogen evolution reaction (HER) from water at neutral pH. Owing to its permanent porosity, the supramolecular structure yields a catalyst film with a 5-fold increase in the number of electrochemically active cobalt atoms and an improvement in Tafel slope from 170 mV/decade to 119 mV/decade compared to a planar cobalt porphyrin analog, reaching activities over 19,000 turnovers for HER over a 24-hour period with 100% Faradaic efficiency.
- Published
- 2021
119. Presentación
- Author
-
Marília Souza Pimenta, Christopher Changwe Nshimbi, and Jerónimo Delgado-Caicedo
- Subjects
Political science ,International relations ,JZ2-6530 - Published
- 2024
- Full Text
- View/download PDF
120. Presentación
- Author
-
Andrés Macías-Tolosa, Marília Souza Pimenta, and Christopher Changwe Nshimbi
- Subjects
Political science ,Political institutions and public administration (General) ,JF20-2112 - Published
- 2024
- Full Text
- View/download PDF
121. Enhanced Electrochemical Stability by Alkyldiammonium in Dion–Jacobson Perovskite toward Ultrastable Light‐Emitting Diodes
- Author
-
Ngai, Kwan Ho, primary, Wei, Qi, additional, Chen, Zefeng, additional, Guo, Xinlu, additional, Qin, Minchao, additional, Xie, Fangyan, additional, Chan, Christopher Chang Sing, additional, Xing, Guichuan, additional, Lu, Xinhu, additional, Chen, Jian, additional, Wong, Kam Sing, additional, Xu, Jianbin, additional, and Long, Mingzhu, additional
- Published
- 2021
- Full Text
- View/download PDF
122. Systemic contact dermatitis caused by acupuncture: A neglected route of allergen entry
- Author
-
Juncai Dong, Yongshi Yang, Christopher Chang, Jing Zhang, Jin-Lyu Sun, Zhouxian Pan, and Rui Tang
- Subjects
Adult ,Chromium ,Male ,medicine.medical_specialty ,business.industry ,Generalized eczema ,Acupuncture Therapy ,Dermatology ,Cobalt ,Allergens ,Patch Tests ,medicine.disease ,medicine.disease_cause ,Metal allergy ,Allergen ,Dermatitis, Allergic Contact ,medicine ,Acupuncture ,Immunology and Allergy ,Humans ,Female ,business ,Contact dermatitis - Published
- 2021
123. Contributors
- Author
-
Nancy Agmon-Levin, Graciela S. Alarcón, Olga Amengual, Stacy P. Ardoin, Swati Arora, Yemil Atisha-Fregoso, John P. Atkinson, Tatsuya Atsumi, Isabelle Ayoub, Maria-Louise Barilla-LaBarca, Bonnie L. Bermas, Sasha Bernatsky, George Bertsias, Tanmayee Bichile, Patrick Blanco, Miyuki Bohgaki, Gisela Bonsmann, Maria Orietta Borghi, Dimitrios T. Boumpas, Rebecka Bourn, Jill P. Buyon, Roberto Caricchio, Edward K.L. Chan, Christopher Chang, Manon Charrier, Cecilia Beatrice Chighizola, Ann E. Clarke, José C. Crispín, Bettina Cuneo, Thomas Dörner, Erika M. Damato, Alastair K.O. Denniston, Amy Devlin, Betty Diamond, T. Ernandez, Titilola Falasinnu, Ruth Fernandez-Ruiz, Brianna Fitzpatrick, Lindsy Forbess, Eleni A. Frangou, Marvin J. Fritzler, Shu Man Fu, Richard Furie, Felicia Gaskin, Dafna Gladman, Caroline Gordon, Amrie C. Grammer, Eric L. Greidinger, Teri M. Greiling, Shuhong Han, James E. Hansen, Sarfaraz A. Hasni, Fadi Hassan, Christian M. Hedrich, Keiju Hiromura, Diane Horowitz, Xin Huang, David Hunt, Peter M. Izmirly, Judith A. James, Wael N. Jarjour, Caroline A. Jefferies, Caroline Jefferies, Xiaoyue Jiang, Mariana J. Kaplan, Takayuki Katsuyama, Munther Khamashta, Kathryn M. Kingsmore, Takao Koike, Dwight H. Kono, Martin A. Kriegel, Annegret Kuhn, Vasileios C Kyttaris, Antonio La Cava, Alexandra Ladouceur, Robert G. Lahita, Aysche Landmann, Estibaliz Lazaro, Mara L. Lennard Richard, Andreia C. Lino, Peter E. Lipsky, M. Kathryn Liszewski, Mindy S. Lo, Qianjin Lu, Mary Mahieu, Susan Malkiel, Susan Manzi, Galina Marder, T.N. Mayadas, Pier Luigi Meroni, Joan T. Merrill, Chandra Mohan, Chi Chiu Mok, Vaishali R. Moulton, Philip I. Murray, Mohammad E. Naffaa, Masaomi Nangaku, Timothy Niewold, K. Okubo, Nancy J. Olsen, Trina Pal, Ziv Paz, Andras Perl, Guillermo J. Pons-Estel, Bo Qu, Anisur Rahman, Ziaur S.M. Raman, Rosalind Ramsey-Goldman, Westley H. Reeves, Christophe Richez, Florencia Rosetti, Brad H. Rovin, Robert L. Rubin, Stephanie Saeli, G. Saggu, Lisa R. Sammaritano, Minoru Satoh, Amr H. Sawalha, Amit Saxena, Savino Sciascia, Syahrul Sazliyana Shaharir, Amir Sharabi, Nan Shen, Robert H. Shmerling, Julia F. Simard, Vanja Sisirak, Samantha Slight-Webb, Isaac Ely Stillman, Sun-Sang J. Sung, Payal Thakkar, Argyrios N. Theofilopoulos, Donald E. Thomas, Jr, Hiromi Tissera, Zahi Touma, Betty P. Tsao, Manuel F. Ugarte-Gil, Murray B. Urowitz, Silvio Manfredo Vieira, Benjamin Wainwright, Daniel J. Wallace, Hongyang Wang, Haijing Wu, Soad Haj Yahia, C. Yung Yu, Zhenhuan Zhao, and Haoyang Zhuang
- Published
- 2021
124. The mechanism of skin damage
- Author
-
Haijing Wu, Qianjin Lu, Christopher Chang, and Xin Huang
- Subjects
Autoimmune disease ,Chemokine ,Lupus erythematosus ,integumentary system ,Effector ,Autoantibody ,Biology ,medicine.disease ,Pathogenesis ,Immune system ,Immunology ,medicine ,biology.protein ,Tumor necrosis factor alpha - Abstract
Lupus erythematosus (LE) is an autoimmune disease that is characterized by pathogenic autoantibodies and immunological attack of multiple organ systems, including the skin. The pathogenesis of skin damage in LE involves both genetic and epigenetic mechanisms. Various environmental triggers can induce LE. Exposure to ultraviolet radiation (UVR) is a prominent trigger factor. UVR has been shown to induce keratinocyte apoptosis and therefore give rise to the externalization of autoantigens, resulting in autoimmune response in skin. Possible downstream mechanisms include stimulation of an immune response through the activation and recruitment of dendritic cells and effector T cells. Certain cytokines and chemokines are upregulated in the process, including type 1 interferon and tumor necrosis factor alpha. In this chapter, we focus on the clinical aspects associated with skin damage and illustrate the underlying cellular and cytokine networks that result in skin damage in LE.
- Published
- 2021
125. Quantification of Temperature-Dependent Charge Separation and Recombination Dynamics in Non-Fullerene Organic Photovoltaics
- Author
-
Chan, Christopher Chang Sing, Ma, Chao, Zou, Xinhui, Xing, Zengshan, Zhang, Guichuan, Yip, Hin-Lap, Taylor, Robert A., He, Yan, Wong, Kam Sing, Chow, Philip C.Y., Chan, Christopher Chang Sing, Ma, Chao, Zou, Xinhui, Xing, Zengshan, Zhang, Guichuan, Yip, Hin-Lap, Taylor, Robert A., He, Yan, Wong, Kam Sing, and Chow, Philip C.Y.
- Abstract
Transient optical spectroscopy is used to quantify the temperature-dependence of charge separation and recombination dynamics in P3TEA:SF-PDI2 and PM6:Y6, two non-fullerene organic photovoltaic (OPV) systems with a negligible driving force and high photocurrent quantum yields. By tracking the intensity of the transient electroabsorption response that arises upon interfacial charge separation in P3TEA:SF-PDI2, a free charge generation rate constant of ≈2.4 × 1010 s−1 is observed at room temperature, with an average energy of ≈230 meV stored between the interfacial charge pairs. Thermally activated charge separation is also observed in PM6:Y6, and a faster charge separation rate of ≈5.5 × 1010 s−1 is estimated at room temperature, which is consistent with the higher device efficiency. When both blends are cooled down to cryogenic temperature, the reduced charge separation rate leads to increasing charge recombination either directly at the donor-acceptor interface or via the emissive singlet exciton state. A kinetic model is used to rationalize the results, showing that although photogenerated charges have to overcome a significant Coulomb potential to generate free carriers, OPV blends can achieve high photocurrent generation yields given that the thermal dissociation rate of charges outcompetes the recombination rate. © 2021 Wiley-VCH GmbH
- Published
- 2021
126. Enhanced Light Emission Performance of Mixed Cation Perovskite Films—The Effect of Solution Stoichiometry on Crystallization
- Author
-
Liu, Fangzhou, Qin, Xinshun, Han, Bing, Chan, Christopher Chang Sing, Ma, Chao, Leung, Tik Lun, Chen, Wei, He, Yanling, Lončarić, Ivor, Grisanti, Luca, Ovčar, Juraj, Skoko, Željko, Shi, Yingli, Ling, Francis Chi Chung, Huqe, Md Rashedul, Zapien, Juan Antonio, Wang, Shixun, Su, Chun-Jen, Jeng, U-Ser, Wong, Kam Sing, Ng, Alan Man Chung, Gu, Meng, Popović, Jasmina, Djurišić, Aleksandra B., Liu, Fangzhou, Qin, Xinshun, Han, Bing, Chan, Christopher Chang Sing, Ma, Chao, Leung, Tik Lun, Chen, Wei, He, Yanling, Lončarić, Ivor, Grisanti, Luca, Ovčar, Juraj, Skoko, Željko, Shi, Yingli, Ling, Francis Chi Chung, Huqe, Md Rashedul, Zapien, Juan Antonio, Wang, Shixun, Su, Chun-Jen, Jeng, U-Ser, Wong, Kam Sing, Ng, Alan Man Chung, Gu, Meng, Popović, Jasmina, and Djurišić, Aleksandra B.
- Abstract
The performance of quasi-2D perovskite light emitting diodes (LEDs) with mixed small cations, cesium and formamidinium (FA), is significantly affected by their ratio. The best devices obtained for Cs:FA ratio of 1:1 exhibit a maximum external quantum efficiency (EQE) of 12.1%, maximum luminance of 15 070 cd m−2 and maximum current efficiency of 46.1 cd A−1, which is significantly higher (about 3 times) compared to devices with FA only (maximum EQE of 4.1%, maximum luminance of 4521 cd m−2) and Cs-only (maximum EQE of 4.0%, maximum luminance of 4886 cd m−2). The photoluminescence quantum yield of the Cs:FA 1:1 sample is similarly enhanced, 21.3% compared 5.4% and 6%, for FA-only and Cs-only samples, respectively. It can be observed that the Cs:FA ratio significantly affects the crystallization of the perovskite, with the optimal 1:1 ratio resulting in the formation of tetragonal Cs0.5FA0.5PbBr3 phase (different from cubic FAPbBr3 and orthorhombic CsPbBr3) with pronounced preferential orientation as well as a significant reduction in the trap density, which leads to a substantial improvement in the light-emitting performance. © 2021 Wiley-VCH GmbH
- Published
- 2021
127. Stable bright perovskite nanoparticle thin porous films for color enhancement in modern liquid crystal displays
- Author
-
Gao, Yiyang, Prodanov, Maksym, Kang, Chengbin, Vashchenko, Valerii, Gupta, Swadesh Kumar, Chan, Christopher Chang Sing, Wong, Kam Sing, Srivastava, Abhishek Kumar, Gao, Yiyang, Prodanov, Maksym, Kang, Chengbin, Vashchenko, Valerii, Gupta, Swadesh Kumar, Chan, Christopher Chang Sing, Wong, Kam Sing, and Srivastava, Abhishek Kumar
- Abstract
Cesium-lead halide perovskite nanoparticles are a promising class of luminescent materials for color and efficient displays. However, material stability is the key issue to solve before we can use these materials in modern displays. Encapsulation is one of the most efficient methods that can markedly improve the stability of perovskite nanoparticles against moisture, heat, oxygen, and light. Thus, we urgently need a low-cost, reliable, and device-compatible encapsulation method for the integration of nanomaterials into display devices. Here, we propose a facile encapsulation method to stabilize perovskite nanoparticles in thin polymer porous films. Using porous polymer films, we achieved good photoluminescence stability in the harsh environment of high temperature, high humidity and strong UV illumination. The good UV stability benefitted from the unique optical properties of the porous film. Besides, we observed photoluminescence enhancement of CsPbBr3 nanoparticle films in a high humidity environment. The stable CsPbBr3 nanoparticle thin porous film provides high brightness (236 nits) and great color enhancement for LCDs and is characterized by simple fabrication with easy scalability, thus it is very suitable for modern LCDs. ©
- Published
- 2021
128. Enhanced Electrochemical Stability by Alkyldiammonium in Dion–Jacobson Perovskite toward Ultrastable Light-Emitting Diodes
- Author
-
Ngai, Kwan Ho, Wei, Qi, Chen, Zefeng, Guo, Xinlu, Qin, Minchao, Xie, Fangyan, Chan, Christopher Chang Sing, Xing, Guichuan, Lu, Xinhu, Chen, Jian, Wong, Kam Sing, Xu, Jianbin, Long, Mingzhu, Ngai, Kwan Ho, Wei, Qi, Chen, Zefeng, Guo, Xinlu, Qin, Minchao, Xie, Fangyan, Chan, Christopher Chang Sing, Xing, Guichuan, Lu, Xinhu, Chen, Jian, Wong, Kam Sing, Xu, Jianbin, and Long, Mingzhu
- Abstract
The electroluminescence efficiency of perovskite light-emitting diodes (PeLEDs) has gained notable achievements, but the poor stability under electric stress severely impedes future practical use. Here, an alkyldiammonium 1,4-butanediamine (BDA) is incorporated into perovskite emitting layer, which substantially optimizes electrochemical stability and minimizes interfacial deep traps under large external bias. The BDA-PeLED shows a record operational half-lifetime T50 of 189.4 h at a high current density of 100 mA cm−2 and 681 h under 50 mA cm−2. Additionally, the device maintains its original performance upon 2500 cycles of voltage scan and withstands 10 000 times of ON–OFF under a pulsed voltage of 2.5 V. Further degradation mechanism study reveals that the main origins of the instability property of PeLEDs without BDA are the generation of deep traps at the interfaces and the infiltration of anions into adjacent layers under long-term electric stress. The significantly enhanced electrochemical stability suggests that alkyldiammonium cation incorporation can provide a direction to solve the instability issue of PeLEDs. © 2021 Wiley-VCH GmbH
- Published
- 2021
129. Unraveling the Temperature Dependence of Exciton Dissociation and Free Charge Generation in Nonfullerene Organic Solar Cells
- Author
-
Ma, Chao, Chan, Christopher Chang Sing, Zou, Xinhui, Yu, Han, Zhang, Jianquan, Yan, He, Wong, Kam Sing, Chow, Chi Yung Philip, Ma, Chao, Chan, Christopher Chang Sing, Zou, Xinhui, Yu, Han, Zhang, Jianquan, Yan, He, Wong, Kam Sing, and Chow, Chi Yung Philip
- Abstract
Organic solar cells based on nonfullerene acceptor molecules show high charge generation yields with negligible driving force at the donor–acceptor (D/A) interface to drive exciton dissociation. Understanding the underlying charge generation dynamics in these material systems is crucial for further development of this technology. Herein, the acceptor exciton dissociation dynamics in these materials is studied using transient optical spectroscopy. The results show that exciton dissociation at the D/A interface takes up to ≈100 ps to complete, and this process is not significantly affected by temperature. A similar timescale for charge transfer (CT) state separation into free electrons and holes is observed at room temperature. But in contrast to the weak temperature dependence of exciton dissociation, the free charge generation rate and yield are significantly reduced at low temperature. This suggests that overcoming the Coulomb barrier for charge separation at the D/A interface is the main reason for the endothermic charge separation observed for these material systems, instead of diffusion-limited exciton dissociation.
- Published
- 2021
130. High-Performance Blue Perovskite Light-Emitting Diodes Enabled by Efficient Energy Transfer between Coupled Quasi-2D Perovskite Layers
- Author
-
Ren, Zhenwei, Yu, Jiahao, Qin, Zhaotong, Wang, Jing, Sun, Jiayun, Chan, Christopher Chang Sing, Ding, Shihao, Wang, Kai, Chen, Rui, Wong, Kam Sing, Lu, Xinhui, Yin, Wan-Jian, Choy, Wallace C. H., Ren, Zhenwei, Yu, Jiahao, Qin, Zhaotong, Wang, Jing, Sun, Jiayun, Chan, Christopher Chang Sing, Ding, Shihao, Wang, Kai, Chen, Rui, Wong, Kam Sing, Lu, Xinhui, Yin, Wan-Jian, and Choy, Wallace C. H.
- Abstract
While there has been extensive investigation into modulating quasi-2D perovskite compositions in light-emitting diodes (LEDs) for promoting their electroluminescence, very few reports have studied approaches involving enhancement of the energy transfer between quasi-2D perovskite layers of the film, which plays very important role for achieving high-performance perovskite LEDs (PeLEDs). In this work, a bifunctional ligand of 4-(2-aminoethyl)benzoic acid (ABA) cation is strategically introduced into the perovskite to diminish the weak van der Waals gap between individual perovskite layers for promoting coupled quasi-2D perovskite layers. In particular, the strengthened interaction between coupled quasi-2D perovskite layers favors an efficient energy transfer in the perovskite films. The introduced ABA can also simultaneously passivate the perovskite defects by reducing metallic Pb for less nonradiative recombination loss. Benefiting from the advanced properties of ABA incorporated perovskites, highly efficient blue PeLEDs with external quantum efficiency of 10.11% and a very long operational stability of 81.3 min, among the best performing blue quasi-2D PeLEDs, are achieved. Consequently, this work contributes an effective approach for high-performance and stable blue PeLEDs toward practical applications. © 2020 Wiley-VCH GmbH
- Published
- 2021
131. Optically Probing Field-Dependent Charge Dynamics in Non-Fullerene Organic Photovoltaics with Small Interfacial Energy Offsets
- Author
-
Zou, Xinhui, Ma, Chao, Chan, Christopher Chang Sing, Zhang, Jianquan, Li, Yunke, Shang, Ao, Wang, Zhen, Arunagiri, Lingeswaran, Qi, Zhenyu, Ade, Harald, Yan, He, Wong, Kam Sing, Chow, Philip C. Y., Zou, Xinhui, Ma, Chao, Chan, Christopher Chang Sing, Zhang, Jianquan, Li, Yunke, Shang, Ao, Wang, Zhen, Arunagiri, Lingeswaran, Qi, Zhenyu, Ade, Harald, Yan, He, Wong, Kam Sing, and Chow, Philip C. Y.
- Abstract
Current non-fullerene organic photovoltaics (OPVs) can achieve high photocurrent generation yields with small donor/acceptor energy offsets. However, the effect of varying energy offset on the charge dynamics in these systems is not fully understood. Here, we use optical spectroscopy to probe charge dynamics in three model non-fullerene systems with varying energy offsets. We find that systems with marginal and negative energy offsets show low photocurrent generation yields and significant radiative recombination from the exciton state. Improved photocurrent generation and suppressed exciton emission is observed when the device is under reverse bias. Our results indicate that photoexcitation of these systems leads to bound charge pairs at the donor/acceptor interface which tend to recombine via the singlet exciton state unless their separation is facilitated by external electric fields. Our results shed light on the charge separation and recombination dynamics in non-fullerene OPVs with small donor/acceptor energy offsets. © 2021 American Chemical Society.
- Published
- 2021
132. Uncovering the Electron-Phonon Interplay and Dynamical Energy-Dissipation Mechanisms of Hot Carriers in Hybrid Lead Halide Perovskites
- Author
-
Chan, Christopher Chang Sing, Fan, Kezhou, Wang, Han, Huang, Zhanfeng, Novko, Dino, Yan, Keyou, Xu, Jianbin, Choy, Wallace C.H., Lončarić, Ivor, Wong, Kam Sing, Chan, Christopher Chang Sing, Fan, Kezhou, Wang, Han, Huang, Zhanfeng, Novko, Dino, Yan, Keyou, Xu, Jianbin, Choy, Wallace C.H., Lončarić, Ivor, and Wong, Kam Sing
- Abstract
The discovery of slow hot carrier cooling in hybrid organic–inorganic lead halide perovskites (HOIPs) has provided exciting prospects for efficient solar cells that can overcome the Shockley–Queisser limit. Questions still loom over how electron-phonon interactions differ from traditional polar semiconductors. Herein, the electron-phonon coupling (EPC) strength of common perovskite films (MAPbBr3, MAPbI3, CsPbI3, and FAPbBr3) is obtained using transient absorption spectroscopy by analyzing the hot carrier cooling thermodynamics via a simplified two-temperature model. Density function theory calculations are numerically performed at relevant electron-temperatures to confirm experiments. Further, the variation of carrier-temperature over a large range of carrier-densities in HOIPs is analyzed, and an “S-shaped” dependence of the initial carrier-temperature to carrier-density is reported. The phenomenon is attributed to the dominance of the large polaron screening and the destabilization effect which causes an increasing-decreasing fluctuation in temperature at low excitation powers; and a hot-phonon bottleneck which effectively increases the carrier temperature at higher carrier-densities. The turning point in the relationship is indicative of the critical Mott density related to the nonmetal-metal transition. The EPC analysis provides a novel perspective to quantify the energy transfer in HOIPs, electron-lattice subsystem, and the complicated screening-bottleneck interplay is comprehensively described, resolving the existing experimental contradictions. © 2021 Wiley-VCH GmbH
- Published
- 2021
133. Perovskite Bifunctional Diode with High Photovoltaic and Electroluminescent Performance by Holistic Defect Passivation
- Author
-
Liu, Zidan, Duan, Chenghao, Liu, Feng, Chan, Christopher Chang Sing, Zhu, Hepeng, Yuan, Ligang, Li, Jiong, Li, Mingjie, Zhou, Biao, Wong, Kam Sing, Yan, Keyou, Liu, Zidan, Duan, Chenghao, Liu, Feng, Chan, Christopher Chang Sing, Zhu, Hepeng, Yuan, Ligang, Li, Jiong, Li, Mingjie, Zhou, Biao, Wong, Kam Sing, and Yan, Keyou
- Abstract
Integration of photovoltaic (PV) and electroluminescent (EL) functions and/or units in one device is attractive for new generation optoelectronic devices but it is challenging to achieve highly comprehensive efficiency. Herein, perovskite solar cells (PSCs) are fabricated, assisted by 3-sulfopropyl methacrylate potassium salt (SPM) additive to tackle this issue. SPMs not only induce large grain size during the film formation but also produce a secondary phase of 2D K2PbI4 to passivate the grain boundaries (GBs). In addition, its sulfonic acid group and potassium ion can coordinate to lead ion and fill the interstitial defects, respectively. Thus, SPM reduces the defective states and suppresses nonradiative recombination loss. As a result, planar PSC delivers a power conversion efficiency of ≈22%, with a maximum open-circuit voltage (Voc) of 1.20 V. The Voc is 94% of the radiative Voc limit (1.28 V), higher than the control device (Voc of 1.12 V). In addition, the reciprocity between PV and EL is also correlated to quantify the energy losses and understand the device physics. When operated as a light-emitting diode, the maximum EL external quantum efficiency (EQEEL) is up to 12.2% (EQEEL of 10.7% under an injection current of short-circuit photocurrent), thus leading to high-performance PV/EL dual functions. © 2021 Wiley-VCH GmbH
- Published
- 2021
134. Case Report: Primary Hypothyroidism Caused by Autoimmune Thyroiditis in Infancy Requires Early Intervention
- Author
-
Robin Nemery, Zina C McSweeney, and Christopher Chang
- Subjects
Autoimmune thyroiditis ,endocrine system ,Pediatrics ,medicine.medical_specialty ,business.industry ,Endocrinology, Diabetes and Metabolism ,Intervention (counseling) ,medicine ,Primary hypothyroidism ,medicine.disease ,business - Abstract
Background: Primary hypothyroidism due to autoimmune thyroiditis is extremely rare in infants, especially under the age of 3 years. For infants, hypothyroidism is most commonly congenital, originating from thyroid dysgenesis with an absent, ectopic, or hypoplastic thyroid gland (1 in 4,000 live births). If left untreated, it can lead to permanent neurodevelopmental deficits. In this report, we describe a male infant who was diagnosed with Hashimoto thyroiditis at 18 months of life, providing a learning example to aid in recognition of this rare disease and enable timely intervention. Clinical Case:Patient was a 2,765 gram, appropriate for gestational age, male born at term with hypospadias of the penis (surgical correction at 11 months). Patient passed meconium in the first 24 hours of life. During the first few months of life, patient developed constipation. Patient had amblyopia necessitating eye patching and began to wear eye glasses at 18 months of life. Patient’s linear and weight growth were within normal limits. Patient had normal motor development, however had language development delay. No known family history of thyroid disease. Screening labs performed at 17-months of age showed abnormal thyroid function: elevated TSH at 14.86 µIU/mL (ref: 0.45 - 4.50 µIU/mL) and normal free T4 level at 1.24 ng/dL (ref: 0.85-1.75 ng/dL). Repeat testing at 18 months of age continued to show elevated TSH at 6.18 µIU/mL (ref: 0.64 - 4.00 µIU/mL), normal free T4 at 1.07 ng/dL (ref: 0.88 - 2.03 ng/dL), and elevated thyroid peroxidase (TPO) antibodies at 163 IU/ml (ref: Conclusions: This case report provides insights into autoimmune thyroiditis in infancy, which, although especially rare under age 3 years, should be considered in infants who present with autoimmunity or abnormal thyroid testing. In the neonatal period, infants’ immune systems are learning to discriminate requirements for self-tolerance versus protection against pathogens and may be more prone to infections. Although autoimmunity in this stage of development is uncommon, there can be breakthroughs in tolerance, as seen in this case. In addition to this patient, two other infants were seen with elevated TPO antibodies, diagnosed at 17 and 31 months old, with similar clinical trends. There remains a need for additional studies providing further insights into autoimmunity in infancy. Importantly, this case illustrates that, when infants have abnormal thyroid levels (with or without other autoimmune conditions), consideration should be made for anti-thyroid antibody testing.
- Published
- 2021
135. Targeted Therapies for Multiple Myeloma
- Author
-
Leow, Christopher Chang-Yew, primary and Low, Michael Sze Yuan, additional
- Published
- 2021
- Full Text
- View/download PDF
136. Consistent Inclusion of Continuum Solvation in Energy Decomposition Analysis: Theory and Application to Molecular CO2 Reduction Catalysts
- Author
-
Martin Head-Gordon, Shaama Mallikarjun Sharada, Christopher Chang, Jeffrey Derrick, Kareesa Kron, Matthias Loipersberger, and Yuezhi Mao
- Abstract
To facilitate computational investigation of intermolecular interactions in the solution phase, we report the development of ALMO-EDA(solv), a scheme that allows the application of continuum solvent models within the framework of energy decomposition analysis (EDA) based on absolutely localized molecular orbitals (ALMOs). In this scheme, all the quantum mechanical states involved in the variational EDA procedure are computed with the presence of solvent environment so that solvation effects are incorporated in the evaluation of all its energy components. After validation on several model complexes, we employ ALMO-EDA(solv) to investigate substituent effects on two classes of complexes that are related to electrochemical CO2 reduction catalysis. For [FeTPP(CO2−κC)]2− (TPP = tetraphenylporphyrin), we reveal that two ortho substituents which yield most favorable CO2 binding, −N(CH3)3+ (TMA) and −OH, stabilize the complex via through-structure and through-space mechanisms, respectively. The Coulombic interaction between the positively charged TMA group and activated CO2 is found to be largely attenuated by the polar solvent. Furthermore, we also provide computational support for the design strategy of utilizing bulky, flexible ligands to stabilize activated CO2 via long-range Coulomb interactions, which creates biomimetic solvent-inaccessible “pockets” in that electrostatics is unscreened. For the reactant and product complexes associated with the electron transfer from the p-terphenyl radical anion to CO2 , we demonstrate that the double terminal substitution of p-terphenyl by electron-withdrawing groups considerably strengthens the binding in the product state while moderately weakens that in the reactant state, which are both dominated by the substituent tuning of the electrostatics component. These applications illustrate that this new extension of ALMO-EDA provides a valuable means to unravel the nature of intermolecular interactions and quantify their impacts on chemical reactivity in solution.
- Published
- 2020
137. Distinct RNA N-Demethylation Pathways Catalyzed by Non-Heme Iron ALKBH5 and FTO Enzymes Enable Regulation of Formaldehyde Release Rates
- Author
-
Christopher Chang, Diana Iovan, Dan He, Eva J. Ge, Kevin Bruemmer, Steven W. M. Crossley, and Joel D.W. Toh
- Abstract
The AlkB family of non-heme-Fe(II)/2-oxoglutarate(2OG)-dependent oxygenases are essential regulators of RNA epigenetics by serving as erasers of one-carbon marks on RNA with release of formaldehyde (FA). Two major human AlkB family members, FTO and ALKBH5, both act as oxidative demethylases of N6 methyladenosine (m6A) but furnish different major products, N6 hydroxymethyladenosine (hm6A) and adenosine (A), respectively. Here we identify foundational mechanistic differences between FTO and ALKBH5 that promote these distinct biochemical outcomes. In contrast to FTO, which follows a traditional oxidative N-demethylation pathway to catalyze conversion of m6A to hm6A with subsequent slow release of A and FA, we find that ALKBH5 catalyzes a directm6A-to-A transformation with rapid FA release. We identify a catalytic R130/K132/Y139 triad within ALKBH5 that facilitates release of FA via an unprecedented covalent-based demethylation mechanism with direct detection of a covalent intermediate. Importantly, a K132Q mutant furnishes an ALKBH5 enzyme with an m6A demethylation profile that resembles that of FTO, establishing the importance of this residue in the proposed covalent mechanism. Finally, we show that ALKBH5 is an endogenous source of FA in the cell by activity-based sensing of FA fluxes perturbed via ALKBH5 knockdown. This work provides a fundamental biochemical rationale for non-redundant roles of these RNA demethylases beyond different substrate preferences and cellular localization, where m6A demethylation by ALKBH5 versus FTO results in release of FA, an endogenous one-carbon unit but potential genotoxin, at different rates in living systems.Significance StatementNon-heme iron enzymes FTO and ALKBH5 play central roles in epigenetic RNA regulation by catalyzing the oxidation of N6-methyladenosine (m6A) to produce N6-hydroxymethyladenosine (hm6A) and adenosine (A), respectively. Here, we provide a mechanistic rationale for these distinct biochemical outcomes by identifying that ALKBH5 performs m6A demethylation via an unprecedented covalent-based mechanism with concomitant and rapid release of A and formaldehyde (FA), whereas FTO liberates hm6A to release A and FA over longer timescales. This work reveals foundational biochemical differences between these closely related but non-redundant epigenetic enzymes and identifies ALKBH5 as an endogenous source of rapid formaldehyde generation in cells.
- Published
- 2020
138. Comparison of Two Intravenous Fluid Management Strategies in COVID-19 Patients in Hubei, China: A Retrospective Multicenter Study
- Author
-
Guogang Xu, Yaping Yuan, Zhanling Wu, Jionghe Wu, Yifan Que, Christopher Chang, Runsheng Wang, Lei Pan, Jing Cheng, Hongxia Li, and Jing Deng
- Subjects
medicine.medical_specialty ,Intravenous fluid ,Multicenter study ,Coronavirus disease 2019 (COVID-19) ,business.industry ,Emergency medicine ,medicine ,China ,business - Abstract
Background Optimal fluid management in patients with COVID-19 has not been reported. This retrospective, multicenter study investigated the impact of intravenous infusion volume in the early stage of COVID-19 on clinical outcomes. Methods 127 patients from two tertiary hospitals were separated into the “conservative” and “liberal” groups based on average daily intravenous infusion volume within the first seven days after admission. Basic information, demographic and epidemiological characteristics, laboratory findings, treatments, and outcome measures were retrieved from medical records. The disease progression and prognosis were analyzed and compared. Results The average daily intravenous infusion volume within 7 days was 500 (150–700) ml/day in the conservative-strategy group (n = 87), and 1100 (1000–1288) ml/day in the liberal-strategy group (n = 40) (p p > 0.05). The final K+ in the liberal group was slightly higher than that at admission, and the final hematocrit level in the conservative group had a significant difference than that at admission (p p = 0.120). However, compared to the liberal group, conservative group had statistically lower rates of disease progression (9.3% vs 37.5%, p p p = 0.012). Conclusions Although there appeared to be no significant difference in the duration of hospitalization between using conservative and liberal fluid management strategies, the former was associated with lower rates of disease progression, mechanical ventilation and in-hospital mortality without increased nonpulmonary-organ dysfunction. These results support the importance of implementing conservative intravenous fluid infusion in the early stage of COVID-19.
- Published
- 2020
139. A Ligand-Directed Approach to Activity-Based Sensing: Developing Palladacycle Fluorescent Probes that Enable Endogenous Carbon Monoxide Detection
- Author
-
Johannes Morstein, Denis Höfler, Kohei Ueno, Jonah Jurss, Ryan Walvoord, Kevin Bruemmer, Samir Rezgui, Thomas Brewer, Minoru Saitoe, Brian Michel, and Christopher Chang
- Abstract
Carbon monoxide (CO) is an emerging gasotransmitter and reactive carbon species with broad anti-inflammatory, cytoprotective, and neurotransmitter functions along with therapeutic potential for the treatment of cardiovascular diseases. The study of CO chemistry in biology and medicine relative to other prominent gasotransmitters such as NO and H2S remains challenging, in large part due to limitations in available tools for the direct visualization of this transient and freely diffusing small molecule in complex living systems. Here we report a ligand-directed activity-based sensing (ABS) approach to CO detection through palladium-mediated carbonylation chemistry. Specifically, the design and synthesis of a series of ABS probes with systematic alterations in the palladium-ligand environment (e.g., sp3-S, sp3-N, sp2-N) establish structureactivity relationships for palladacycles to confer selective reactivity with CO under physiological conditions. These fundamental studies led to the development of an optimized probe, termed Carbon Monoxide Probe-3 Ester Pyridine (COP3E-Py), which enables imaging of CO release in live cell and brain settings, including monitoring of endogenous CO production that triggers presynaptic dopamine release in fly brains. This work provides a unique tool for studying CO in living systems and establishes the utility of a synthetic methods approach to activity-based sensing using principles of organometallic chemistry
- Published
- 2020
140. Type I Interferons in the Pathogenesis and Treatment of Autoimmune Diseases
- Author
-
Jiao Jiang, Haijing Wu, Ming Zhao, Christopher Chang, and Qianjin Lu
- Subjects
0301 basic medicine ,Arthritis ,Autoimmune Diseases ,Epigenesis, Genetic ,Pathogenesis ,03 medical and health sciences ,0302 clinical medicine ,Immune system ,medicine ,Immunology and Allergy ,Animals ,Humans ,Genetic Predisposition to Disease ,skin and connective tissue diseases ,Juvenile dermatomyositis ,030203 arthritis & rheumatology ,Autoimmune disease ,Innate immune system ,business.industry ,Disease Management ,General Medicine ,medicine.disease ,030104 developmental biology ,Type I interferon signaling pathway ,Gene Expression Regulation ,Organ Specificity ,Rheumatoid arthritis ,Immunology ,Interferon Type I ,Cytokines ,Disease Susceptibility ,business ,Biomarkers ,Signal Transduction - Abstract
Type I interferons (IFN-Is) are a very important group of cytokines that are produced by innate immune cells but also act on adaptive immune cells. IFN-Is possess antiviral, antitumor, and anti-proliferative effects, as well are associated with the initiation and maintenance of autoimmune disorders. Studies have shown that aberrantly expressed IFN-Is and/or type I IFN-inducible gene signatures in the serum or tissues of patients with autoimmune disorders are linked to their pathogenesis, clinical manifestations, and disease activity. Type I interferonopathies with mutations in genes impacting the type I IFN signaling pathway have shown symptoms and characteristics similar to those of systemic lupus erythematosus (SLE). Furthermore, both interventions in animal models and clinical trials of therapies targeting the type I IFN signaling pathway have shown efficacy in the treatment of autoimmune diseases. Our review aims to summarize the functions and targeted therapies (as well as clinical trials) of IFN-Is in both adult and pediatric autoimmune diseases, such as SLE, pediatric SLE (pSLE), rheumatoid arthritis (RA), juvenile idiopathic arthritis (JIA), juvenile dermatomyositis (JDM), Sjogren syndrome (SjS), and systemic sclerosis (SSc), discussing the potential abnormal regulation of transcription factors and epigenetic modifications and providing a potential mechanism for pathogenesis and therapeutic strategies for future clinical use.
- Published
- 2020
141. The Epigenetics of Lupus Erythematosus
- Author
-
Haijing, Wu, Christopher, Chang, and Qianjin, Lu
- Subjects
Humans ,Lupus Erythematosus, Systemic ,DNA Methylation ,Autoantibodies ,Epigenesis, Genetic - Abstract
Systemic lupus erythematosus (SLE) is a life-threatening autoimmune disease that is characterized by dysregulated dendritic cells, T and B cells, and abundant autoantibodies. The pathogenesis of lupus remains unclear. However, increasing evidence has shown that environment factors, genetic susceptibilities, and epigenetic regulation contribute to abnormalities in the immune system. In the past decades, several risk gene loci have been identified, such as MHC and C1q. However, genetics cannot explain the high discordance of lupus incidence in homozygous twins. Environmental factor-induced epigenetic modifications on immune cells may provide some insight. Epigenetics refers to inheritable changes in a chromosome without altering DNA sequence. The primary mechanisms of epigenetics include DNA methylation, histone modifications, and non-coding RNA regulations. Increasing evidence has shown the importance of dysregulated epigenetic modifications in immune cells in pathogenesis of lupus, and has identified epigenetic changes as potential biomarkers and therapeutic targets. Environmental factors, such as drugs, diet, and pollution, may also be the triggers of epigenetic changes. Therefore, this chapter will summarize the up-to-date progress on epigenetics regulation in lupus, in order to broaden our understanding of lupus and discuss the potential roles of epigenetic regulations for clinical applications.
- Published
- 2020
142. The Epigenetics of Food Allergy
- Author
-
Christopher, Chang, Haijing, Wu, and Qianjin, Lu
- Subjects
Epigenomics ,Immune Tolerance ,Humans ,Food Hypersensitivity ,Epigenesis, Genetic - Abstract
Food allergy is a global health problem, particularly in developed countries. It is mainly mediated by Th2 cell and IgE produced by B cells. While the pathogenesis of IgE-mediated food allergy is quite straightforward, the factors that lead to the development of food allergies at any age in children and adults are unclear. Recent studies have revealed that genetics, epigenetics, and environmental exposures contribute to the development of atopy. In this chapter, we discuss the interplay between these three key elements, reveal how epigenetic modifications may mediate genetic susceptibility of food allergies, and explain why epigenetic modifications may be the key in environmental factors mediated-gene expression, leading to the loss of immune tolerance and eventually, the initiation of food allergies. It should be noted that the study of the role of epigenetics in food allergy is still in its infancy, and lags behind research on epigenetics in other fields such as cancer and autoimmune diseases. One of the reasons for this may be the extreme complexity and variability of clinical presentation of food allergy, ranging from less severe forms such as oral allergy syndrome to full-blown anaphylaxis. Research on early exposure has disrupted the previous thinking of avoidance of food allergies to prevent sensitization in children, instead leading to recommendations that early introduction to foods may, in fact, induce tolerance. However, clear and unequivocal guidelines on how to approach this in the clinical setting have not been developed. The coming of the epigenetic era in food allergies is to provide better understanding of pathogenesis of food allergy, as well as providing therapeutic and preventive strategies for this very common condition.
- Published
- 2020
143. The Role of Epigenetics in Type 1 Diabetes
- Author
-
Zhiguo, Xie, Christopher, Chang, Gan, Huang, and Zhiguang, Zhou
- Subjects
Epigenomics ,Diabetes Mellitus, Type 1 ,Humans ,Genetic Predisposition to Disease ,DNA Methylation ,Epigenesis, Genetic - Abstract
Type 1 diabetes (T1D) is an autoimmune disease caused by the interaction between genetic alterations and environmental factors. More than 60 susceptible genes or loci of T1D have been identified. Among them, HLA regions are reported to contribute about 50% of genetic susceptibility in Caucasians. There are many environmental factors involved in the pathogenesis of T1D. Environmental factors may change the expression of genes through epigenetic mechanisms, thus inducing individuals with susceptible genes to develop T1D; however, the underlying mechanisms remain poorly understood. The major epigenetic modifications include DNA methylation, histone modification, and non-coding RNA. There has been extensive research on the role of epigenetic mechanisms including aberrant DNA methylation, histone modification, and microRNA in the pathogenesis of T1D. DNA methylation and microRNA have been proposed as biomarkers to predict islet β cell death, which needs further confirmation before any clinical application can be developed. Small molecule inhibitors of histone deacetylases, histone methylation, and DNA methylation are potentially important for preventing T1D or in the reprogramming of insulin-producing cells. This chapter mainly focuses on T1D-related DNA methylation, histone modification, and non-coding RNA, as well as their possible translational potential in the early diagnosis and treatment of T1D.
- Published
- 2020
144. Epigenetics in Health and Disease
- Author
-
Lian, Zhang, Qianjin, Lu, and Christopher, Chang
- Subjects
Epigenomics ,Histone Code ,MicroRNAs ,Health ,Animals ,Humans ,Disease ,DNA Methylation ,Epigenesis, Genetic - Abstract
Epigenetic mechanisms, which include DNA methylation, histone modification, and microRNA (miRNA), can produce heritable phenotypic changes without a change in DNA sequence. Disruption of gene expression patterns which are governed by epigenetics can result in autoimmune diseases, cancers, and various other maladies. Mechanisms of epigenetics include DNA methylation (and demethylation), histone modifications, and non-coding RNAs such as microRNAs. Compared to numerous studies that have focused on the field of genetics, research on epigenetics is fairly recent. In contrast to genetic changes, which are difficult to reverse, epigenetic aberrations can be pharmaceutically reversible. The emerging tools of epigenetics can be used as preventive, diagnostic, and therapeutic markers. With the development of drugs that target the specific epigenetic mechanisms involved in the regulation of gene expression, development and utilization of epigenetic tools are an appropriate and effective approach that can be clinically applied to the treatment of various diseases.
- Published
- 2020
145. Reply to Tsolaki and Zakynthinos: Are Patients with COVID-19 Dying of or with Cardiac Injury?
- Author
-
Lei Tu, Qinyong Hu, Yang Jin, Guogang Xu, Xi Wang, Yingzhen Du, Pingjun Zhu, and Christopher Chang
- Subjects
Pulmonary and Respiratory Medicine ,2019-20 coronavirus outbreak ,Coronavirus disease 2019 (COVID-19) ,biology ,business.industry ,SARS-CoV-2 ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,Pneumonia, Viral ,MEDLINE ,COVID-19 ,Critical Care and Intensive Care Medicine ,biology.organism_classification ,medicine.disease ,Virology ,Pneumonia ,Betacoronavirus ,Pandemic ,Correspondence ,Medicine ,Humans ,business ,Coronavirus Infections ,Pandemics - Published
- 2020
146. Corrigendum to 'The deadly coronaviruses: The 2003 SARS pandemic and the 2020 novel coronavirus epidemic in China' [J. Autoimmun. 109C (2020) 102434]
- Author
-
Yongshi Yang, Kai Guan, Christopher Chang, Runsheng Wang, Jinlyu Sun, Fujun Peng, Taijiao Jiang, Guogang Xu, and Ming Yang
- Subjects
2019-20 coronavirus outbreak ,China ,Coronavirus disease 2019 (COVID-19) ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,Pneumonia, Viral ,Immunology ,Genome, Viral ,medicine.disease_cause ,Severe Acute Respiratory Syndrome ,History, 21st Century ,Article ,Betacoronavirus ,COVID-19 Testing ,Zoonoses ,Pandemic ,medicine ,Pyroptosis ,Animals ,Humans ,Immunology and Allergy ,Pandemics ,Coronavirus ,business.industry ,Clinical Laboratory Techniques ,Information Dissemination ,SARS-CoV-2 ,COVID-19 ,Virology ,COVID-19 Drug Treatment ,Quarantine ,business ,Coronavirus Infections - Abstract
The 2019-nCoV is officially called SARS-CoV-2 and the disease is named COVID-19. This viral epidemic in China has led to the deaths of over 1800 people, mostly elderly or those with an underlying chronic disease or immunosuppressed state. This is the third serious Coronavirus outbreak in less than 20 years, following SARS in 2002-2003 and MERS in 2012. While human strains of Coronavirus are associated with about 15% of cases of the common cold, the SARS-CoV-2 may present with varying degrees of severity, from flu-like symptoms to death. It is currently believed that this deadly Coronavirus strain originated from wild animals at the Huanan market in Wuhan, a city in Hubei province. Bats, snakes and pangolins have been cited as potential carriers based on the sequence homology of CoV isolated from these animals and the viral nucleic acids of the virus isolated from SARS-CoV-2 infected patients. Extreme quarantine measures, including sealing off large cities, closing borders and confining people to their homes, were instituted in January 2020 to prevent spread of the virus, but by that time much of the damage had been done, as human-human transmission became evident. While these quarantine measures are necessary and have prevented a historical disaster along the lines of the Spanish flu, earlier recognition and earlier implementation of quarantine measures may have been even more effective. Lessons learned from SARS resulted in faster determination of the nucleic acid sequence and a more robust quarantine strategy. However, it is clear that finding an effective antiviral and developing a vaccine are still significant challenges. The costs of the epidemic are not limited to medical aspects, as the virus has led to significant sociological, psychological and economic effects globally. Unfortunately, emergence of SARS-CoV-2 has led to numerous reports of Asians being subjected to racist behavior and hate crimes across the world.
- Published
- 2020
147. Clinical Pathway for Early Diagnosis of COVID-19: Updates from Experience to Evidence-Based Practice
- Author
-
Lei Tu, Guogang Xu, Fujun Peng, Yingzhen Du, Tianzhi Li, Yongshi Yang, Ming Yin, Christopher Chang, Peng Hu, Taijiao Jiang, Jinlyu Sun, and Runsheng Wang
- Subjects
0301 basic medicine ,medicine.medical_specialty ,ARDS ,COVID-19 Vaccines ,Pneumonia, Viral ,Disease ,Antibodies, Viral ,Real-Time Polymerase Chain Reaction ,Severity of Illness Index ,Procalcitonin ,Patient Isolation ,03 medical and health sciences ,Betacoronavirus ,0302 clinical medicine ,Clinical pathway ,COVID-19 Testing ,Pandemic ,medicine ,Eosinopenia ,Immunology and Allergy ,Humans ,Serologic Tests ,Intensive care medicine ,Medical History Taking ,False Negative Reactions ,Lung ,Pandemics ,030203 arthritis & rheumatology ,COPD ,business.industry ,Clinical Laboratory Techniques ,Reverse Transcriptase Polymerase Chain Reaction ,SARS-CoV-2 ,COVID-19 ,General Medicine ,medicine.disease ,030104 developmental biology ,Early Diagnosis ,Respiratory failure ,Immunoglobulin M ,Evidence-Based Practice ,Immunoglobulin G ,Quarantine ,Critical Pathways ,RNA, Viral ,business ,Coronavirus Infections ,Tomography, X-Ray Computed ,Algorithms - Abstract
The COVID-19 pandemic is a significant global event in the history of infectious diseases. The SARS-CoV-2 appears to have originated from bats but is now easily transmissible among humans, primarily through droplet or direct contact. Clinical features of COVID-19 include high fever, cough, and fatigue which may progress to ARDS. Respiratory failure can occur rapidly after this. The primary laboratory findings include lymphopenia and eosinopenia. Elevated D-dimer, procalcitonin, and CRP levels may correlate with disease severity. Imaging findings include ground-glass opacities and patchy consolidation on CT scan. Mortality is higher in patients with hypertension, cardiac disease, diabetes mellitus, cancer, and COPD. Elderly patients are more susceptible to severe disease and death, while children seem to have lower rates of infection and lower mortality. Diagnostic criteria and the identification of persons under investigation have evolved as more data has emerged. However, the approach to diagnosis is still very variable from region to region, country to country, and even among different hospitals in the same city. The importance of a clinical pathway to implement the most effective and relevant diagnostic strategy is of critical importance to establish the control of this virus that is responsible for more and more deaths each day.
- Published
- 2020
148. An NADH-Inspired Redox Mediator Strategy to Promote Second-Sphere Electron and Proton Transfer for Cooperative Electrochemical CO2 Reduction Catalyzed by Iron Porphyrin
- Author
-
Peter T. Smith, Sophia Weng, and Christopher Chang
- Abstract
We present a bioinspired strategy for enhancing electrochemical carbon dioxide reduction catalysis by cooperative use of base-metal molecular catalysts with intermolecular second-sphere redox mediators that facilitate both electron and proton transfer. Functional synthetic mimics of the biological redox cofactor NADH, which are electrochemically stable and are capable of mediating both electron and proton transfer, can enhance the activity of an iron porphyrin catalyst for electrochemical reduction of CO2 to CO, achieving a 13-fold rate improvement without altering the intrinsic high selectivity of this catalyst platform for CO2 versus proton reduction. Evaluation of a systematic series of NADH analogs and redox-inactive control additives with varying proton and electron reservoir properties reveals that both electron and proton transfer contribute to the observed catalytic enhancements. This work establishes that second-sphere dual control of electron and proton inventories is a viable design strategy for developing more effective electrocatalysts for CO2 reduction, providing a starting point for broader applications of this approach to other multi-electron, multi-proton transformations.
- Published
- 2020
149. Management strategies for patients with autoimmune diseases during the COVID-19 pandemic: A perspective from China
- Author
-
Christopher Chang, Yu Liu, and Qianjin Lu
- Subjects
lcsh:Immunologic diseases. Allergy ,2019-20 coronavirus outbreak ,medicine.medical_specialty ,Coronavirus disease 2019 (COVID-19) ,business.industry ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,Short Communication ,Perspective (graphical) ,MEDLINE ,Family medicine ,Pandemic ,Medicine ,business ,China ,lcsh:RC581-607 - Published
- 2020
150. The pathogenesis, diagnosis and clinical manifestations of steroid-induced osteonecrosis
- Author
-
M. Eric Gershwin, Adam Greenspan, and Christopher Chang
- Subjects
0301 basic medicine ,Diagnostic Imaging ,Immunology ,Avascular necrosis ,Wrist ,Bioinformatics ,Severity of Illness Index ,Parkin ,Pathogenesis ,03 medical and health sciences ,Femoral head ,0302 clinical medicine ,Coagulopathy ,Immunology and Allergy ,Medicine ,Humans ,Genetic Predisposition to Disease ,Glucocorticoids ,030203 arthritis & rheumatology ,business.industry ,Osteonecrosis ,Disease Management ,medicine.disease ,Combined Modality Therapy ,030104 developmental biology ,medicine.anatomical_structure ,Steroids ,Disease Susceptibility ,Differential diagnosis ,Ankle ,Symptom Assessment ,business ,Biomarkers ,Signal Transduction - Abstract
Corticosteroid associated osteonecrosis is bone death resulting from the use of chronic glucocorticoids and most commonly affects the femoral head, although the bones such as around knee joint, wrist joint and ankle joint can be affected. The pathogenesis is likely multifactorial, with genetic and environmental factors playing a role. Epigenetics may be the mechanism by which environment exerts it effects. In spite of recent discoveries, the exact pathogenesis of corticosteroid associated osteonecrosis is unknown. Over the past few years, more miRNA's have been found to be associated with osteonecrosis. The older mechanisms such as a coagulopathy, abnormalities in apoptosis and lipid metabolism dysfunction are still believed to play a role. The role of inflammatory pathways including the PDK1/AKT/mTOR signaling pathway, the PERK and Parkin pathways have been increasingly recognized as playing a mechanistic role. Histological damage to the joint can occur before the presence of symptoms. The most common symptoms are pain and an inability to bear weight. Differential diagnosis includes infection, bone marrow edema syndrome or subchondral fracture. Early detection is important for successful management of the condition. MRI is the best radiologic technique to diagnosis femoral head osteonecrosis. Multiple staging systems for osteonecrosis have been used over the years, including the Ficat and Arlet system and the Steinberg criteria. The later stages of these staging systems are irreversible. Both non-surgical (conservative) and surgical modes of therapy are used in the treatment of osteonecrosis.
- Published
- 2020
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.