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54. Crowd Agile Model for Effective Software Development

Author

Qayyum, Shamaila, Imtiaz, Salma, Khan, Huma Hayyat, van der Aalst, Wil, Series Editor, Mylopoulos, John, Series Editor, Rosemann, Michael, Series Editor, Shaw, Michael J., Series Editor, Szyperski, Clemens, Series Editor, Paasivaara, Maria, editor, and Kruchten, Philippe, editor

Published
2020
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57. Relationship between Bilingual Instruction and Learners' Performance in English as Second Language Context

Author

Khan, Huma Imran

Abstract

The prime purpose of this study was to explore a correlation between bilingual instruction in an ESL class and the class performance of the ESL learners at the secondary level. Quantitative research method was used to evaluate the test performance of 60 ESL learners divided into two groups: One was the controlled group (which was given instructions in L2 only) and the other was the treatment group (which was given instructions in both L1 and L2) in Public School settings. Apart from the students, 15 language teachers' feedback upon their perceptions of L1 usage in L2 classrooms was taken by using the Likert scale feedback forms. The results confirmed that the instructions given bilingually are directly associated to improved learner outcomes and teachers' responses for the usage of L1 in classrooms showed a strong positive response.

Published
2015

58. Optogenetic Control of Heart Rhythm by Selective Stimulation of Cardiomyocytes Derived from Pnmt+ Cells in Murine Heart.

Author

Wang, Yanwen, Lin, Wee, Crawford, William, Ni, Haibo, Bolton, Emma, Khan, Huma, Shanks, Julia, Bub, Gil, Wang, Xin, Paterson, David, Zhang, Henggui, Galione, Antony, Ebert, Steven, Terrar, Derek, and Lei, Ming

Subjects
Animals, Calcium Signaling, Electrophysiological Phenomena, Fluorescent Antibody Technique, Gene Expression, Genes, Reporter, Heart Rate, Immunohistochemistry, Mice, Mice, Transgenic, Myocardium, Myocytes, Cardiac, Optogenetics, Phenylethanolamine N-Methyltransferase
Abstract

In the present study, channelrhodopsin 2 (ChR2) was specifically introduced into murine cells expressing the Phenylethanolamine n-methyltransferase (Pnmt) gene, which encodes for the enzyme responsible for conversion of noradrenaline to adrenaline. The new murine model enabled the identification of a distinctive class of Pnmt-expressing neuroendocrine cells and their descendants (i.e. Pnmt+ cell derived cells) within the heart. Here, we show that Pnmt+ cells predominantly localized to the left side of the adult heart. Remarkably, many of the Pnmt+ cells in the left atrium and ventricle appeared to be working cardiomyocytes based on their morphological appearance and functional properties. These Pnmt+ cell derived cardiomyocytes (PdCMs) are similar to conventional myocytes in morphological, electrical and contractile properties. By stimulating PdCMs selectively with blue light, we were able to control cardiac rhythm in the whole heart, isolated tissue preparations and single cardiomyocytes. Our new murine model effectively demonstrates functional dissection of cardiomyocyte subpopulations using optogenetics, and opens new frontiers of exploration into their physiological roles in normal heart function as well as their potential application for selective cardiac repair and regeneration strategies.

Published
2017

60. Approved treatments for neovascular age-related macular degeneration: current safety and future directions

Author

Khan, Hannah, Aziz, Aamir A., Khanani, Zoha, Khan, Huma, Mojumder, Ohidul, Gahn, Greggory M., and Khanani, Arshad M.

Abstract

ABSTRACTIntroductionAge-related macular degeneration (AMD) is a progressive retinal degenerative disease that is implicated as one of the leading causes of visual impairment in the elderly population. Vascular endothelial growth factor (VEGF) has been identified as the main driver of AMD, and various therapeutics have revolutionized the treatment and management of neovascular AMD (nAMD) with favorable visual and anatomical outcomes.Areas coveredPhysicians have a variety of approved therapeutics in their arsenal for patients with varying disease progression and patient-specific needs, with the ultimate goal of achieving optimal visual and anatomic outcomes. The literature search was conducted using PubMed, Google Scholar, and sources from companies’ websites, allowing us to locate findings recently presented at conferences.Expert opinionScientific advancements in the field have led to newly approved therapeutics and devices, such as the port-delivery system with ranibizumab (PDS), and further investigation is ongoing in the realm of gene therapy for retinal diseases. In addition to efficacy and durability, newer agents must have comparable safety profiles to older agents in order to be used broadly. These options introduce a level of complexity in nAMD treatment; however, physicians to personalize treatment to improve vision in nAMD patients and reduce treatment burden overall.

Published
2024
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99. Mechanistic studies of the explosive degrading enzyme, pentaerythritol tetranitrate (PETN) reductase

Author

Khan, Huma

Subjects
662.27
Abstract

PETN reductase is a member of the old yellow enzyme (OYE) family of flavoproteins. The enzyme is able to utilise diverse substrates such as a/b-unsaturated compounds, nitrate esters and nitroaromatic explosives, which makes it of potential interest of phytoremediation purposes. This thesis describes the characterisation of PETN reductase and investigates the role of four active site residues. Trp 102 is shown to influence the binding and transformation of TNT/picric acid. PETN reductase transforms TNT via two competing pathways; (i) nitro group reduction and (ii) direct ring reduction leading to hydride-Meisenheimer complex formation. Mutation of Trp 102 significantly affects the stability of the hydride-Meisenheimer complex, which is sufficient to affect the concentration distribution and/or nature of final TNT degradation products. The ability to produce the TNT hydride-Meisenheimer complex is abolished in the H181A and H184A mutant enzymes indicating that His 181 and His 184 determine the initial route of TNT transformation. These residues are also crucial in ligand binding. Hydride transfer to 2-cyclohexenone and nitrocyclohexene is compromised in the H181A and H184A PETN reductases, owing to the altered mode of substrate binding. Tyr compounds, however, studies presented herein reveal that his is not the case. Trp 102 and Tyr 186 are also shown to play a key role in GTN reduction. Studies on the reductive half-reaction reveal that the rate of NADPH-enzyme complex formation occurs too fast to be measured with Y186F enzyme. Conversely, no complex formation between NADPH and the H181A and H184A mutant enzymes is observed, attributed to the perturbation in NADPH binding, which favours hydride transfer. Collectively, the research described proposes interesting implications into the underlying mechanism of TNT and 2-cyclohexneone reduction by the OYE family of enzymes.

Published
2004

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