299 results on '"Prasad AK"'
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2. Influence of Metal Forming Process in the Fatigue life of Axle Housings & Failure Investigation
- Author
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Prabhakar, M., Prasad, AK., Paswan, M.K., and Tendulkar, Vishveshwar
- Published
- 2020
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3. Influenza and Parainfluenza
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Prasad, AK, primary
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- 2014
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4. Estimation of indoor and outdoor effective doses and lifetime cancer risk from gamma dose rates along the coastal regions of Kollam district, Kerala
- Author
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Jojo, PJ, primary, Monica, S, additional, Visnu Prasad, AK, additional, and Soniya, SR, additional
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- 2016
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5. The GenoChip: A New Tool for Genetic Anthropology
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Elhaik, E, Greenspan, E, Staats, S, Krahn, T, Tyler-Smith, C, Xue, Y, Tofanelli, S, Francalacci, P, Cucca, F, Pagani, Luca, Jin, L, Li, H, Schurr, Tg, Greenspan, B, Spencer Wells, R, Acosta, O, Adhikarla, S, Adler, Cj, Balanovska, E, Balanovsky, O, Bertranpetit, J, Clarke, Ac, Comas, D, Cooper, A, Dulik, Mc, Gaieski, Jb, Ganesh Prasad AK, Haak, W, Haber, M, Kaplan, Me, Lacerda, Dr, Li, S, Martinez-Cruz, B, Matisoo-Smith, Ea, Merchant, Nc, Mitchell, Jr, Owings, Ac, Parida, L, Pitchappan, R, Platt, De, Quintana-Murci, L, Renfrew, C, Royyuru, Ak, Sandoval, Jr, Santhakumari, Av, Santos, Fr, Der Sarkissian CSI, Soodyall, S, Soria Hernanz DF, Swamikrishnan, P, Vieira, Pp, Vilar, Mg, Zalloua, Pa, and Ziegle, Js
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Letter ,Anthropology ,Human Migration ,Population genetics ,Genética de población ,Ancestry-informative marker ,Human genetic variation ,MED/03 Genetica medica ,Genética humana ,DNA, Mitochondrial ,Polymorphism, Single Nucleotide ,Haplogroup ,genetic anthropology ,AimsFinder ,03 medical and health sciences ,0302 clinical medicine ,Genes, Y-Linked ,Human Genome Project ,Genetics ,Humans ,Quantitative Biology - Genomics ,Genographic Project ,Quantitative Biology - Populations and Evolution ,Genotyping ,Denisovan ,Antropologia ,Ecology, Evolution, Behavior and Systematics ,Anthropology, Cultural ,History, Ancient ,030304 developmental biology ,GenoChip ,Oligonucleotide Array Sequence Analysis ,Genomics (q-bio.GN) ,0303 health sciences ,Genètica humana ,Genètica de poblacions ,biology ,BIO/18 Genetica ,Populations and Evolution (q-bio.PE) ,population genetics ,Especiación genética ,biology.organism_classification ,FOS: Biological sciences ,haplogroups ,Haplotipos ,030217 neurology & neurosurgery ,Human mitochondrial DNA haplogroup - Abstract
The Genographic Project is an international effort using genetic data to chart human migratory history. The project is non-profit and non-medical, and through its Legacy Fund supports locally led efforts to preserve indigenous and traditional cultures. In its second phase, the project is focusing on markers from across the entire genome to obtain a more complete understanding of human genetic variation. Although many commercial arrays exist for genome-wide SNP genotyping, they were designed for medical genetic studies and contain medically related markers that are not appropriate for global population genetic studies. GenoChip, the Genographic Project's new genotyping array, was designed to resolve these issues and enable higher-resolution research into outstanding questions in genetic anthropology. We developed novel methods to identify AIMs and genomic regions that may be enriched with alleles shared with ancestral hominins. Overall, we collected and ascertained AIMs from over 450 populations. Containing an unprecedented number of Y-chromosomal and mtDNA SNPs and over 130,000 SNPs from the autosomes and X-chromosome, the chip was carefully vetted to avoid inclusion of medically relevant markers. The GenoChip results were successfully validated. To demonstrate its capabilities, we compared the FST distributions of GenoChip SNPs to those of two commercial arrays for three continental populations. While all arrays yielded similarly shaped (inverse J) FST distributions, the GenoChip autosomal and X-chromosomal distributions had the highest mean FST, attesting to its ability to discern subpopulations. The GenoChip is a dedicated genotyping platform for genetic anthropology and promises to be the most powerful tool available for assessing population structure and migration history., Comment: 11 pages, 5 Figures, 2 supplementary notes
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- 2013
6. The novel use of an external fixator connecting rod and synthetic bone substitute to achieve anatomic reduction of depressed tibial plateau fracture fragments
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Prasad, AK, primary, Rashid, M, additional, and Heidari, N, additional
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- 2015
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7. Polycystic horseshoe kidney
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Ram, R, primary, Swarnalatha, G, additional, Shetty, M, additional, Naidu, GD, additional, Dakshinamurty, KV, additional, and Prasad, AK, additional
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- 2013
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8. Effect of oral administration of carbofuran on male reproductive system of rat
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Pant, N., primary, Prasad, AK, additional, Srivastava, SC, additional, Shankar, R., additional, and Srivastava, SP, additional
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- 1995
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9. Effect of dermal application of hexachlorocyclohexane (HCH) on male reproductive system of rat
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Prasad, AK, primary, Pant, N., additional, Srivastava, SC, additional, Kumar, R., additional, and Srivastava, SP, additional
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- 1995
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10. Regioselective deacylation of polyacetoxy aryl-methyl ketones by lipases in organic solvents
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Parmar, Vs, primary, Prasad, Ak, additional, Sharma, Nk, additional, Singh, Sk, additional, Pati, Hn, additional, and Gupta, Suman, additional
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- 1992
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11. Characterization of 7-amino-4-methylcoumarin as an effective antitubercular agent: structure-activity relationships.
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Tandon R, Ponnan P, Aggarwal N, Pathak R, Baghel AS, Gupta G, Arya A, Nath M, Parmar VS, Raj HG, Prasad AK, and Bose M
- Published
- 2011
12. Role of enteric adenoviruses and rotaviruses in mild and severe acute enteritis
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P. Raj, Ranjana Srivastava, Lennart Svensson, Prasad Ak, G. Stintzing, Maharaj K. Bhan, Nita Bhandari, and S. Jayashree
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Diarrhea ,Rotavirus ,Microbiology (medical) ,medicine.medical_specialty ,Pediatrics ,India ,Enzyme-Linked Immunosorbent Assay ,Rural Health ,medicine.disease_cause ,Gastroenterology ,Enteritis ,Excretion ,Feces ,Hospitals, Urban ,Internal medicine ,medicine ,Humans ,In patient ,Dehydration ,business.industry ,Adenoviruses, Human ,Infant ,Acute gastroenteritis ,medicine.disease ,Infectious Diseases ,Child, Preschool ,Pediatrics, Perinatology and Child Health ,medicine.symptom ,Detection rate ,business ,Urban hospital - Abstract
The role of enteric-type adenoviruses and rotaviruses in mild and severe acute gastroenteritis was investigated among children younger than 5 years of age seeking treatment at an urban hospital (UH) and at a rural health center (RHC) in India. There were 330 children at the UH and 340 at the RHC; 319 and 315 age matched nondiarrheal children served as controls for the respective groups. Rotavirus was detected in 15.2% of 330 cases and 1.9% of 319 controls at the UH (P less than 0.001) and in 16.5% of 340 cases and 2.9% of 315 controls at the RHC (P less than 0.001). RV excretion was 3- to 5-fold more common in severe compared with mild diarrhea at the UH and at the RHC (P less than 0.001). The detection rate for enteric-type adenoviruses was similar in patients and controls, respectively, at the UH (0.9%; 2.5%) and RHC (3.8%; 2.5%). At the RHC adenovirus types other than 40 and 41 were excreted by 8.8% of the patients and by only 1.0% of the controls (P less than 0.001). It is possible that the diarrheagenic role of adenoviruses may not be restricted to types 40 and 41.
- Published
- 1988
13. Short- and long-term regulation of 3-hydroxy 3-methylglutaryl coenzyme A reductase by a 4-methylcoumarin
- Author
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Ashok K. Prasad, Luciano Saso, Ashish Dhawan, Virinder S. Parmar, Marco Segatto, Veronica Simeoni, Laura Trapani, Valentina Balducci, Sandra Incerpi, Valentina Pallottini, Trapani, Laura, Segatto, Marco, Simeoni, Veronica, Balducci, Valentina, Dhawan, Ashish, Parmar, Virinder S, Prasad, Ashok K, Saso, Luciano, Incerpi, Sandra, Pallottini, Valentina, Trapani, L, Simeoni, V, Balducci, V, Dhawan, A, Parmar, V, Prasad, Ak, and Saso, L
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Oxidant ,7-Dehydrocholesterol reductase ,Antioxidant ,Time Factors ,antioxidant ,3-hydroxy 3-methylglutaryl coenzyme a reductase ,Time Factor ,Coenzyme A ,medicine.medical_treatment ,Blotting, Western ,Hep G2 Cell ,Reductase ,Coumarin ,Hydroxymethylglutaryl CoA Reductase ,Biochemistry ,chemistry.chemical_compound ,Coumarins ,Catalytic Domain ,medicine ,Humans ,Protein Phosphatase 2 ,Umbelliferones ,Phosphorylation ,chemistry.chemical_classification ,reactive oxygen species ,Reactive oxygen species ,Molecular Structure ,Cholesterol ,4-methylcoumarins ,cholesterol ,methylcoumarin ,General Medicine ,Hep G2 Cells ,Hydrogen Peroxide ,Oxidants ,Hydroxymethylglutaryl-CoA reductase ,chemistry ,LDL receptor ,Hydroxymethylglutaryl CoA Reductases ,lipids (amino acids, peptides, and proteins) ,Reactive Oxygen Specie ,Sterol Regulatory Element Binding Protein 1 ,Oxidation-Reduction ,Human ,Sterol Regulatory Element Binding Protein 2 - Abstract
"""Dyslipidemia is one of the most significant risk factors for cardiovascular diseases. Cholesterol homeostasis. is regulated by both the receptor-mediated endocytosis of Low Density Lipoproteins by LDL. receptors and de novo cholesterol synthesis via the rate-limiting enzyme 3-hydroxy-3-methylglutaryl. coenzyme A reductase. Although statins, 3-hydroxy-3-methylglutaryl coenzyme A reductase substrate. competitors, have revolutionized the management of cardiovascular diseases by lowering serum LDL,. their side effects range from myalgia to rhabdomyolysis. Treatment with antioxidant compounds could. represent an efficient alternative in the modulation of 3-hydroxy-3-methylglutaryl coenzyme A reductase. activity. Indeed it has already been demonstrated that the rise in reactive oxygen species levels. causes the complete dephosphorylation and, in turn activation of the enzyme.. Many coumarins and their derivatives have the special ability to scavenge reactive oxygen species or. show a lipid lowering potential.. Here we evaluated whether the coumarin, 4-methylesculetin could exert both the ability to scavenge. ROS and to modulate 3-hydroxy-3-methylglutaryl coenzyme A reductase in HepG2 cell line where the. enzyme activity dysregulation induced by reactive oxygen species has already been reported.. The antioxidant property of 4-methylesculetin led to the reduction of 3-hydroxy-3-methylglutaryl. coenzyme A reductase activation state through the increase of the enzyme phosphorylation. In addition,. this coumarin showed the ability to modulate 3-hydroxy-3-methylglutaryl coenzyme A reductase. protein levels both by transcriptional and degradational events independent of its antioxidant activity."""
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- 2011
14. Chandipura Virus Resurgence: Insights from Indian Outbreaks and the Path Forward.
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Garg R, Prasad AK, and Agarwala P
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Background: First isolated in 1965 from a case of febrile encephalopathy, the Chandipura virus (CHPV) causes sporadic cases as well as periodic outbreaks of encephalitis in parts of India. Transmitted by sandflies and mosquitoes, CHPV infection has high mortality within 48 hours of hospitalisation, with children bearing the brunt of the illness. The virus garnered global attention in the middle of 2024 as India witnessed its largest outbreak in the last two decades., Objective: This article aims to synthesise the existing knowledge on various aspects of CHPV and outline current actions needed as well as potential directions for future research., Content: Between early June and August 15th 2024, India reported 245 cases of encephalitis from the states of Gujarat and Rajasthan, 64 of which were laboratory-confirmed CHPV infections. The mortality toll of the outbreak was 82, accounting for a case fatality rate of 33%. With this outbreak, the virus has expanded its niche from central and southern to north-western India. Significant advancements in the understanding of the neuropathogenesis of the virus and the development of diagnostic assays have been made in the 21
st century. However, no specific antiviral drugs or vaccines are available. A G-protein-based recombinant vaccine and an inactivated vaccine have shown favourable results in pre-clinical trials. The need of the hour is to fast-track the development of an effective vaccine. A high suspicion for early identification and prompt referral of cases, decentralized diagnostic facilities, sensitization of healthcare workers, integrated vector management and effective reporting and surveillance systems are all needed to curb the menace of this perilous pathogen. The current outbreak should serve as a wake-up call to foster intersectoral collaboration between policymakers, public health experts, epidemiologists, virologists, neurologists, paediatricians, and anthropologists to develop and implement effective strategies against the virus., Competing Interests: Declaration of Competing Interest ☒ The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Indian Association of Medical Microbiologists. Published by Elsevier B.V. All rights reserved.)- Published
- 2024
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15. Spatiotemporal determination of photoinduced strain in a Weyl semimetal.
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Wu J, Prasad AK, Balatsky A, and Weissenrieder J
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The application of dynamic strain holds the potential to manipulate topological invariants in topological quantum materials. This study investigates dynamic structural deformation and strain modulation in the Weyl semimetal WTe
2 , focusing on the microscopic regions with static strain defects. The interplay of static strain fields, at local line defects, with dynamic strain induced from photo-excited coherent acoustic phonons results in the formation of local standing waves at the defect sites. The dynamic structural distortion is precisely determined utilizing ultrafast electron microscopy with nanometer spatial and gigahertz temporal resolutions. Numerical simulations are employed to interpret the experimental results and explain the mechanism for how the local strain fields are transiently modulated through light-matter interaction. This research provides the experimental foundation for investigating predicted phenomena such as the mixed axial-torsional anomaly, acoustogalvanic effect, and axial magnetoelectric effects in Weyl semimetals, and paves the road to manipulate quantum invariants through transient strain fields in quantum materials., Competing Interests: The authors have no conflicts to disclose., (© 2024 Author(s).)- Published
- 2024
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16. Minimum 10-Y Follow-Up of Vitamin-E-Diffused Highly Crosslinked Polyethylene Liners in Total Hip Arthroplasty: A Comparative Evaluation From a Prospective, International, Multicenter Cohort Study.
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Nepple CM, Blackburn AZ, Feder OI, Prasad AK, and Bedair HS
- Abstract
Background: Total hip arthroplasty (THA) is a proven and effective treatment for end-stage osteoarthritis. The success of THA is due in part to highly crosslinked polyethylene (XL) implants. In 2007, a new generation of polyethylene liners entered clinical use. The new liners infused polyethylene with vitamin E and became vitamin E infused polyethylene (EP). The EP liner was hypothesized to prevent the loss of mechanical properties caused by oxidation, extending the lifetime of the implant. This international prospective study aimed to quantify the clinical outcomes of a 977 patient cohort receiving EP and XL liners 10 years after surgery., Methods: The prospective cohort study began in 2007, including eight countries and 17 centers. The final cohort included 977 patients (EP liner: n = 520; XL liner: n = 457). Patients were followed preoperatively, postoperatively, and at 1, 3, 5, 7, and 10 years. Each follow-up visit involved clinical evaluation, radiography, and survey collection. The demographics and revisions were also recorded. Mann-Whitney U tests were used to evaluate statistical differences., Results: At 10 years following surgery, 534 patients were eligible for follow-up. Of those eligible, 352 patients returned for clinical evaluation (65.9% eligible; 36.0% overall). No statistical differences were found (P > 0.05) in the demographics of the followed-up cohort. The linear wear rates were 0.00338 mm/year for EP liners and 0.0236 mm/year for XL liners using individual regression (P < 0.0001). No significant difference was observed in wear rates using cohort regression. Similarly, surveys suggested no significant outcomes between the EP and XL liner cohorts. The overall incidence of revision was 2.3% for EP and 2.0% for XL liners., Conclusions: The EP liner demonstrated significantly lower wear than its XL counterparts at 10 years after implantation. Results are promising, as vitamin E polyethylene may improve the lifetime performance of THA implants and ensure that arthroplasty innovations reflect the changing patient population., (Copyright © 2024. Published by Elsevier Inc.)
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- 2024
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17. Origin of Secondary Structure Transitions and Peptide Self-Assembly Propensity in Trifluoroethanol-Water Mixtures.
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Prasad AK, Samajdar R, Panwar AS, and Martin LL
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- Circular Dichroism, Peptides chemistry, Molecular Dynamics Simulation, Trifluoroethanol chemistry, Water chemistry, Protein Structure, Secondary
- Abstract
Membrane-peptide interactions are key to the formation of helical intermediates in the early stages of amyloidogenesis. Aqueous solutions of 2,2,2-trifluoroethanol (TFE) provide a membrane-mimetic environment capable of promoting and stabilizing local peptide interactions. Uperin 3.5 (U3.5), a 17-residue and amidated antimicrobial peptide, is unstructured in water but self-assembles into fibrils in the presence of salt. Secondary structure transitions linked to U3.5 self-assembly were investigated in TFE/water mixtures, in both the absence and presence of salt, to assess the role of membrane-peptide interactions on peptide self-assembly and amyloid formation. A 5-to-7-fold increase in fibril yield of U3.5 was observed at low TFE concentrations (10% TFE/water v/v) compared with physiological buffer but only in the presence of salt. No aggregation was observed in salt-free TFE/water mixtures. Circular dichroism spectra showed that partial helical structures, initially stabilized by TFE, transitioned to β-sheet-rich aggregates in a saline buffer. Molecular dynamics simulations confirmed that TFE and salt act synergistically to enhance peptide-peptide interactions, resulting in β-sheet-rich U3.5 oligomers at low TFE concentrations. Specifically, TFE stabilized amphipathic, helical intermediates, leading to increased peptide-peptide attraction through hydrophobic interactions. The presence of salt further enhanced the peptide-peptide interactions by screening positively charged residues. Thus, the study revealed the role of a membrane mimic in stabilizing helical intermediates on the pathway to amyloid formation in the antimicrobial U3.5 peptide.
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- 2024
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18. The Role of Risk Tolerance in a Patient's Decision to Undergo Total Knee and Hip Arthroplasty.
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Blackburn AZ, Prasad AK, Scott BL, Cote M, Humphrey TJ, Katakam A, Salimy MS, Lim P, Heng M, Melnic CM, and Bedair HS
- Abstract
Background: A patient's decision-making process to undergo surgery is crucial for surgeons to understand for patient-counseling purposes. Total knee and hip arthroplasty, like any other major surgery, is associated with serious, sometimes life-threatening, complications. Using the results of discrete choice experiments (DCEs), we aimed to understand the relationship between a patient's risk tolerance and choosing to undergo surgery in real life., Methods: This is a retrospective study of prospectively collected DCE results for 142 potential knee or hip arthroplasty clinic patients from October 2021 to March 2022. The DCE presented the patient with 2 scenarios, each of which was made up of different combinations of attributes and levels. A hierarchal Bayesian model was used to obtain a risk score that reflected the risk attributes chosen by each patient. Logistic regressions were then used to evaluate the association between a patient's willingness to incur risk and their decision to undergo a total joint arthroplasty., Results: Of the 142 patients enrolled in the DCE, 89 (62.3%) underwent a total joint arthroplasty. Risk score (odds ratio [OR] = 2.6, 95% confidence interval [CI] 1.1 to 6.6, P = 0.04), men (OR = 2.5, 95% CI 1.1 to 5.9, P = 0.028), and patients who have hip osteoarthritis (OR = 2.4, 95% CI 1.1 to 5.5, P = 0.036) increased the odds of undergoing arthroplasty, whereas physical function of at least 75% at the initial visit (OR = 0.3, 95% CI 0.1 to 0.7, P = 0.004) decreased these odds., Conclusions: We found that a patient's willingness to incur risk, lower baseline physical function, and men were all independently associated with undergoing total knee arthroplasty. We believe that these findings prompt much-needed future studies that focus solely on the relationship between patients' inherent risk behavior and surgical and patient-reported outcomes., (Copyright © 2024. Published by Elsevier Inc.)
- Published
- 2024
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19. Novel bilayer 2D V 2 O 5 as a potential catalyst for fast photodegradation of organic dyes.
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Reshma PR, Prasad AK, and Dhara S
- Abstract
Two-dimensional (2D) materials have recently drawn interest in various applications due to their superior electronic properties, high specific surface area, and surface activity. However, studies on the catalytic properties of the 2D counterpart of V
2 O5 are scarce. In the present study, the catalytic properties of 2D V2 O5 vis-à-vis bulk V2 O5 for the degradation of methylene blue dye are discussed for the first time. The 2D V2 O5 catalyst was synthesized using a modified chemical exfoliation technique. A massive increase in the electrochemically active surface area of 2D V2 O5 by one order of magnitude greater than that of bulk V2 O5 was observed in this study. Simultaneously, ~ 7 times increase in the optical absorption coefficient of 2D V2 O5 significantly increases the number of photogenerated electrons involved in the catalytic performance. In addition, the surface activity of the 2D V2 O5 catalyst is enhanced by generating surface oxygen vacancy defects. In the current study, we have achieved ~ 99% degradation of 16 ppm dye using the 2D V2 O5 nanosheet catalysts under UV light exposure with a remarkable degradation rate constant of 2.31 min-1 , which is an increase of the order of 102 from previous studies using V2 O5 nanostructures and nanocomposites as catalysts. Since the enhanced photocatalytic activity emerged from the surface and optical properties of the catalyst, the current study shows great promise for the future application of 2D V2 O5 in photo- and electrocatalysis., (© 2024. The Author(s).)- Published
- 2024
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20. A novel multi-model estimation of phosphorus in coal and its ash using FTIR spectroscopy.
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Vinod A, Prasad AK, Mishra S, Purkait B, Mukherjee S, Shukla A, Desinayak N, Sarkar BC, and Varma AK
- Abstract
The level of phosphorus must be carefully monitored for proper and effective utilization of coal and coal ash. The phosphorus content needs to be assessed to optimize combustion efficiency and maintenance costs of power plants, ensure quality, and minimize the environmental impact of coal and coal ash. The detection of low levels of phosphorus in coal and coal ash is a significant challenge due to its complex chemical composition and low concentration levels. Effective monitoring requires accurate and sensitive equipment for the detection of phosphorus in coal and coal ash. X-ray fluorescence (XRF) is a commonly used analytical technique for the determination of phosphorus content in coal and coal ash samples but proves challenging due to their comparatively weak fluorescence intensity. Fourier Transform Infrared spectroscopy (FTIR) emerges as a promising alternative that is simple, rapid, and cost-effective. However, research in this area has been limited. Until now, only a limited number of research studies have outlined the estimation of major elements in coal, predominantly relying on FTIR spectroscopy. In this article, we explore the potential of FTIR spectroscopy combined with machine learning models (piecewise linear regression-PLR, partial least square regression-PLSR, random forest-RF, and support vector regression-SVR) for quantifying the phosphorus content in coal and coal ash. For model development, the methodology employs the mid-infrared absorption peak intensity levels of phosphorus-specific functional groups and anionic groups of phosphate minerals at various working concentration ranges of coal and coal ash. This paper proposes a multi-model estimation (using PLR, PLSR, and RF) approach based on FTIR spectral data to detect and rapidly estimate low levels of phosphorus in coal and its ash (R 2 of 0.836, RMSE of 0.735 ppm, RMSE (%) of 34.801, MBE of - 0.077 ppm, MBE (%) of 5.499, and MAE of 0.528 ppm in coal samples and R 2 of 0.803, RMSE of 0.676 ppm, RMSE (%) of 38.050, MBE of - 0.118 ppm, MBE (%) of 4.501, and MAE of 0.474 ppm in coal ash samples). Our findings suggest that FTIR combined with the multi-model approach combining PLR, PLSR, and RF regression models is a reliable tool for rapid and near-real-time measurement of phosphorus in coal and coal ash and can be suitably modified to model phosphorus content in other natural samples such as soil, shale, etc., (© 2024. The Author(s).)
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- 2024
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21. Electrophoretic Deposition as a Versatile Low-Cost Tool to Construct a Synthetic Polymeric Solid-Electrolyte Interphase on Silicon Anodes: A Model System Investigation.
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Mou RJ, Barua S, Prasad AK, Epps TH 3rd, and Yao KPC
- Abstract
The cycling of next-generation, high-capacity silicon (Si) anodes capable of 3579 mAh·g
-1 is greatly hindered by the instability of the solid-electrolyte interphase (SEI). The large volume changes of Si during (de)lithiation cause continuous cracking of the SEI and its reconstruction, leading to loss of lithium inventory and extensive consumption of electrolyte. The SEI formed in situ during cell cycling is mostly composed of molecular fragments and oligomers, the structure of which is difficult to tailor. In contrast, ex situ formation of a synthetic SEI provides greater flexibility to deposit long-chain, polymeric, and elastomeric components potentially capable of maintaining integrity against the large ∼350% volume expansion of Si while also enabling electronic passivation of the surface for longer cycling and calendar life. Furthermore, polymers are amenable to structural modifications, and the desired elasticity can be targeted by selection of the SEI polymer feedstock. Herein, electrophoretic deposition (EPD) is used to apply chitosan as a synthetic SEI on model Si thin film electrodes. Comparison of synthetic SEIs obtained without (Si/Chit) and with CH3 COOLi (Si/Chit+CH3 COOLi) added during EPD is performed to demonstrate a facile route to tuning of the polymer SEI chemistry. Atomic force and scanning electron microscopy reveal that addition of CH3 COOLi at EPD assists in conformal deposition of the synthetic SEI. During electrochemical cycling, the Chit+CH3 COOLi coating nearly doubles the capacity retention versus the reference bare Si thin film. X-ray photoelectron and Fourier transform infrared spectroscopy reveal that CH3 COOLi caps the -NH2 groups of chitosan through amidation during EPD, which suppresses the catalytic reduction of the electrolyte. The presented approach demonstrates and validates EPD as a low-capital route to achieving and chemistry-tuning synthetic SEIs on Si electrodes. More broadly, the method is a promising avenue toward controlled and tailored polymeric SEIs on various conversion-type electrodes with high particle volumetric expansion.- Published
- 2024
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22. Synthesis of substituted 2H-Chromenes via Pd-catalyzed C-H activation and thermal cyclization.
- Author
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Maikhuri VK, Verma V, Mathur D, Prasad AK, and Khatri V
- Subjects
- Cyclization, Catalysis, Palladium, Benzopyrans
- Abstract
A proficient approach has been developed for the synthesis of substituted 2H-chromenes from C1-substituted glucal. The key step of our synthetic methodology was C-H activation in propylene carbonate solvent followed by 6π-electrocyclization aromatization in ethylene glycol as greener substitutes to toxic aprotic solvents, to obtain 2H-chromenes in a stepwise manner. The application of the developed methodology was further explored with the synthesis of a small library of substituted 2H-chromenes in good yields., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)
- Published
- 2024
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23. Triazole-linked Nucleic Acids: Synthesis, Therapeutics and Synthetic Biology Applications.
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Sharma VK, Mangla P, Singh SK, and Prasad AK
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- Nucleic Acids chemical synthesis, Nucleic Acids chemistry, Humans, Oligonucleotides chemical synthesis, Oligonucleotides chemistry, Oligonucleotides, Antisense chemical synthesis, RNA, Small Interfering chemical synthesis, Triazoles chemical synthesis, Triazoles chemistry, Synthetic Biology methods
- Abstract
This article covers the triazole-linked nucleic acids where the triazole linkage (TL) replaces the natural phosphate backbone. The replacement is done at either a few selected linkages or all the phosphate linkages. Two triazole linkages, the four-atom TL1 and the six-atom TL2, have been discussed in detail. These triazole-modified oligonucleotides have found a wide range of applications, from therapeutics to synthetic biology. For example, the triazole-linked oligonucleotides have been used in the antisense oligonucleotide (ASO), small interfering RNA (siRNA) and clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 technology as therapeutic agents. Due to the ease of the synthesis and a wide range of biocompatibility, the triazole linkage TL2 has been used to assemble a functional 300-mer DNA from alkyne- and azide-functionalized 100-mer oligonucleotides as well as an epigenetically modified variant of a 335 base-pair gene from ten short oligonucleotides. These outcomes highlight the potential of triazole-linked nucleic acids and open the doors for other TL designs and artificial backbones to fully exploit the vast potential of artificial nucleic acids in therapeutics, synthetic biology and biotechnology., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)
- Published
- 2024
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24. Nonequilibrium Phonon Dynamics and Its Impact on the Thermal Conductivity of the Benchmark Thermoelectric Material SnSe.
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Prasad AK, Šebesta J, Esteban-Puyuelo R, Maldonado P, Ji S, Sanyal B, Grånäs O, and Weissenrieder J
- Abstract
Thermoelectric materials play a vital role in the pursuit of a sustainable energy system by allowing the conversion of waste heat to electric energy. Low thermal conductivity is essential to achieving high-efficiency conversion. The conductivity depends on an interplay between the phononic and electronic properties of the nonequilibrium state. Therefore, obtaining a comprehensive understanding of nonequilibrium dynamics of the electronic and phononic subsystems as well as their interactions is key for unlocking the microscopic mechanisms that ultimately govern thermal conductivity. A benchmark material that exhibits ultralow thermal conductivity is SnSe. We study the nonequilibrium phonon dynamics induced by an excited electron population using a framework combining ultrafast electron diffuse scattering and nonequilibrium kinetic theory. This in-depth approach provides a fundamental understanding of energy transfer in the spatiotemporal domain. Our analysis explains the dynamics leading to the observed low thermal conductivity, which we attribute to a mode-dependent tendency to nonconservative phonon scattering. The results offer a penetrating perspective on energy transport in condensed matter with far-reaching implications for rational design of advanced materials with tailored thermal properties.
- Published
- 2023
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25. Minimum 7-Year Follow-Up of Vitamin E-Diffused and Highly Cross-Linked Polyethylene Liners in Total Hip Arthroplasty: Findings From a Prospective, International, Multicenter Study of 977 Patients.
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Collins AK, Sauder N, Nepple CM, Blackburn AZ, Prasad AK, Feder OI, Melnic CM, and Bedair HS
- Subjects
- Humans, Polyethylene, Vitamin E, Follow-Up Studies, Prospective Studies, Prosthesis Failure, Prosthesis Design, Arthroplasty, Replacement, Hip adverse effects, Hip Prosthesis
- Abstract
Background: Vitamin E-diffused highly cross-linked polyethylene (VEPE) acetabular liners for total hip arthroplasty (THA) have shown favorable results in small cohort studies. However, larger studies are warranted to compare its performance to highly cross-linked polyethylene (XLPE) and demonstrate clinical significance in 10-year arthroplasty outcomes. This study compared acetabular liner wear and patient-reported outcome measures (PROMs) between patients treated with VEPE and XLPE liners in a prospective, international, multicenter study with minimum 7-year follow-up., Methods: A total of 977 patients (17 centers; 8 countries) were enrolled from 2007 to 2012. The centers were randomly assigned to implants. At 1-year, 3-year, 5-year, and 7-year postoperative visits, radiographs, PROMs, and incidence of revision were collected. Acetabular liner wear was calculated using computer-assisted vector analysis of serial radiographs. General health, disease progression, and treatment satisfaction reported by patients were scored using 5 validated surveys and compared using Mann-Whitney U tests. At 7 years, 75.4% of eligible patients submitted data., Results: The mean acetabular liner wear rate was -0.009 mm/y and 0.024 mm/y for the VEPE and XLPE group, respectively (P = .01). There were no statistically significant differences in PROMs. The overall revision incidence was 1.8% (n = 18). The revision incidence in VEPE and XLPE cohorts were 1.92% (n = 10) versus 1.75% (n = 8), respectively., Conclusion: We found that VEPE acetabular liners in total hip arthroplasty led to no significant clinical difference in 7-year outcomes as measured by acetabular liner wear rate, PROMs, and revision rate. While VEPE liners showed less wear, the wear rate for both the VEPE and XLPE liners was below the threshold for osteolysis. Therefore, the difference in liner wear may indicate comparative clinical performance at 7 years, as further indicated by the lack of difference in PROMs and the low revision incidence., (Copyright © 2023. Published by Elsevier Inc.)
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- 2023
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26. Assessing the Utility of ChatGPT Throughout the Entire Clinical Workflow: Development and Usability Study.
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Rao A, Pang M, Kim J, Kamineni M, Lie W, Prasad AK, Landman A, Dreyer K, and Succi MD
- Subjects
- Humans, Clinical Decision-Making, Organizations, Workflow, User-Centered Design, Artificial Intelligence
- Abstract
Background: Large language model (LLM)-based artificial intelligence chatbots direct the power of large training data sets toward successive, related tasks as opposed to single-ask tasks, for which artificial intelligence already achieves impressive performance. The capacity of LLMs to assist in the full scope of iterative clinical reasoning via successive prompting, in effect acting as artificial physicians, has not yet been evaluated., Objective: This study aimed to evaluate ChatGPT's capacity for ongoing clinical decision support via its performance on standardized clinical vignettes., Methods: We inputted all 36 published clinical vignettes from the Merck Sharpe & Dohme (MSD) Clinical Manual into ChatGPT and compared its accuracy on differential diagnoses, diagnostic testing, final diagnosis, and management based on patient age, gender, and case acuity. Accuracy was measured by the proportion of correct responses to the questions posed within the clinical vignettes tested, as calculated by human scorers. We further conducted linear regression to assess the contributing factors toward ChatGPT's performance on clinical tasks., Results: ChatGPT achieved an overall accuracy of 71.7% (95% CI 69.3%-74.1%) across all 36 clinical vignettes. The LLM demonstrated the highest performance in making a final diagnosis with an accuracy of 76.9% (95% CI 67.8%-86.1%) and the lowest performance in generating an initial differential diagnosis with an accuracy of 60.3% (95% CI 54.2%-66.6%). Compared to answering questions about general medical knowledge, ChatGPT demonstrated inferior performance on differential diagnosis (β=-15.8%; P<.001) and clinical management (β=-7.4%; P=.02) question types., Conclusions: ChatGPT achieves impressive accuracy in clinical decision-making, with increasing strength as it gains more clinical information at its disposal. In particular, ChatGPT demonstrates the greatest accuracy in tasks of final diagnosis as compared to initial diagnosis. Limitations include possible model hallucinations and the unclear composition of ChatGPT's training data set., (©Arya Rao, Michael Pang, John Kim, Meghana Kamineni, Winston Lie, Anoop K Prasad, Adam Landman, Keith Dreyer, Marc D Succi. Originally published in the Journal of Medical Internet Research (https://www.jmir.org), 22.08.2023.)
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- 2023
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27. Efficient and stereoselective synthesis of sugar fused pyrano[3,2- c ]pyranones as anticancer agents.
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Kumar S, Sahu RK, Kumari P, Maity J, Kumar B, Chhatwal RJ, Singh BK, and Prasad AK
- Abstract
A highly stereoselective, efficient and facile route was achieved for the synthesis of novel and biochemically potent sugar fused pyrano[3,2- c ]pyranone derivatives starting from inexpensive, naturally occurring d-galactose and d-glucose. First, β- C -glycopyranosyl aldehydes were synthesized from these d-hexose sugars in six steps, with overall yields 41-55%. Next, two different 1- C -formyl glycals were synthesized from these β- C -glycopyranosyl aldehydes by treatment in basic conditions. The optimization of reaction conditions was carried out following reactions between 1- C -formyl galactal and 4-hydroxycoumarin. Next, 1- C -formyl galactal and 1- C -formyl glucal were treated with nine substituted 4-hydroxy coumarins at room temperature (25 °C) in ethyl acetate for ∼1-2 h in the presence of l-proline to obtain exclusively single diastereomers of pyrano[3,2- c ]pyranone derivatives in excellent yields. Four compounds were found to be active for the MCF-7 cancer cell line. The MTT assay, apoptosis assay and migration analysis showed significant death of the cancer cells induced by the synthesized compounds., Competing Interests: The authors declare no competing financial interest., (This journal is © The Royal Society of Chemistry.)
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- 2023
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28. C -Glycopyranosyl aldehydes: emerging chiral synthons in organic synthesis.
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Kumar S, Khatri V, Mangla P, Chhatwal RJ, Parmar VS, and Prasad AK
- Abstract
Herein, we have summarized the vast array of synthetic processes that have been developed for the synthesis of C -glycopyranosyl aldehydes and diverse C -glycoconjugates derived from them by covering the literature reported from 1979 to 2023. Notwithstanding its challenging chemistry, C -glycosides are considered stable pharmacophores and are used as important bioactive molecules. The discussed synthetic methodologies to access C -glycopyranosyl aldehydes take advantage of seven key intermediates, viz. allene, thiazole, dithiane, cyanide, alkene, and nitromethane. Furthermore, the integration of complex C -glycoconjugates derived from varied C -glycopyranosyl aldehydes involves nucleophilic addition/substitution, reduction, condensation, oxidation, cyclo condensation, coupling, and Wittig reactions. In this review, we have categorized the synthesis of C -glycopyranosyl aldehydes and C -glycoconjugates on the basis of the methodology used for their synthesis and on types of C -glycoconjugates, respectively., Competing Interests: The authors declare no conflict of interest., (This journal is © The Royal Society of Chemistry.)
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- 2023
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29. Helical intermediate formation and its role in amyloids of an amphibian antimicrobial peptide.
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Prasad AK, Martin LL, and Panwar AS
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- Animals, Molecular Dynamics Simulation, Protein Conformation, beta-Strand, Amphibians, Amyloid beta-Peptides chemistry, Amyloid chemistry, Antimicrobial Peptides
- Abstract
Helical intermediates appear to be crucial in the amyloid formation of several amyloidogenic peptides, including Aβ, that are implicated in different neurodegenerative diseases. Intermediate species of amyloid formation have been reported to be more toxic than mature amyloid fibrils. Hence, the current work focuses on understanding the mechanistic roles of the helical intermediates in the early stages of amyloid self-assembly in amyloidogenic peptides. Molecular dynamics (MD) simulations and the adaptive biasing force (ABF) method were utilized to investigate structural changes that lead to amyloid formation in amphibian peptide uperin-3.5 (U3.5), an antimicrobial and amyloidogenic peptide. Microsecond time-scale MD simulations revealed that peptide aggregation, into β-sheet dominated aggregates, is centred on two important factors; evolution of α-helical intermediates and the critical role of local peptide concentration inside these aggregates. Electrostatic attraction between the oppositely charged aspartate ( D ) and arginine ( R ) residues located near the N-terminus induced hydrogen bonding resulting in the formation of precursor 3
10 -helices close to the N-terminus. The 310 -helices transitioned into α-helices, thereby imparting partial helical conformations to the peptides. In the initial stages of aggregation, U3.5 peptides with amphipathic, partial helices were driven closer by hydrophobic interactions to form small clusters of helical intermediates. These helices imparted stability to the helical intermediates, which promoted the growth of clusters by further addition of peptides. This led to an increase in the local peptide concentration, which enabled stronger peptide-peptide interactions and triggered a β-sheet transition in these aggregates. Thus, this study emphasized that the helical intermediates may be crucial to the evolution of β-sheet-rich amyloid structures.- Published
- 2023
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30. Chemoenzymatic synthesis of bridged homolyxofuranosyl pyrimidine nucleosides: Bicyclic AZT analogues.
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Singla H, Kumar S, Kavita, Maity J, and Prasad AK
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- Nucleosides, Thymine, Uracil, Antiviral Agents, Pyrimidine Nucleosides
- Abstract
A greener chemo-enzymatic methodology has been developed for the synthesis of conformationally restricted diastereomeric homolyxofuranosyl pyrimidines (AZT analogue), i.e., (5'R)-3'-azido-3'-deoxy-2'-O,5'-C-bridged-β-d-homolyxofuranosyl-uracil and thymine starting from inexpensive diacetone-d-glucofuranose in 18% and 21% overall yields, respectively. In one of the key steps in multistep synthesis of bicyclic AZT analogues, the primary hydroxyl group of 3'-azido-3'-deoxy-β-d-glucofuranosyl pyrimidines has been acetylated using Novozyme® 435 in THF in 92% and 97% yields, respectively. The monoacetylated nucleoside was converted to desired bicyclic AZT analogue in two steps in an overall yield of 82% and 83%, respectively., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)
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- 2023
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31. Evaluation of the Health and Nutritional Status of Discharged Children From Malnutrition Treatment Centres Using Mobile Phone Calls During the COVID-19 Lockdown in Jharkhand, India.
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Kiran KA, Kujur M, Kumari R, Sagar V, Kumar D, Hassen G, Kashyap V, Prasad AK, and Rana RK
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Background The Indian state of Jharkhand has the highest rate of wasting (29%) among young children. Mobile audio call follow-up can be used to assess such children with severe acute malnutrition (SAM). Aim This study evaluated SAM children during the COVID-19 outbreak and learn more about the status of their home/community care, and caregivers' awareness of integrated child development services (ICDS) and COVID-19 prevention. Methods Contact numbers of caregivers for discharged children were obtained from 54 malnutrition treatment centers (MTCs). In April and June 2020, mentors conducted follow-up interviews using mobile phone calls. Results Seven children (1.72%) were reported dead and 400 were alive, mostly girls (59.5%). Only a few caregivers observed post-discharge ailments (15.4%) and weight loss (7.7%) in their children. Children aged six to 24 months were characterized by continued breastfeeding (88.0%) at most five to six times a day (45.8%). Most of the children were not fed as per maternal infant and young child feeding protocols. Age in months with an adjusted odds ratio (OR) of 0.55 (1.00-1.11) as a 95% confidence interval (CI), age category, with an adjusted OR of 4.32 (1.71- 10.94) as 95% CI, and breastfeeding with adjusted OR 1.85 (1.07- 3.21) as 95% CI were three major predictors for a well-fed child. Conclusion Community involvement is crucial in the follow-up of children with SAM for effective rehabilitation. Mobile phone audio call follow-up is a relatively cost-effective approach to tackle geographic barriers and COVID-19 lockdown-induced situations. There are major gaps mainly in informing caregivers on how to manage COVID-19 with breastfeeding., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2023, Kiran et al.)
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- 2023
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32. Rational design of a highly immunogenic prefusion-stabilized F glycoprotein antigen for a respiratory syncytial virus vaccine.
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Che Y, Gribenko AV, Song X, Handke LD, Efferen KS, Tompkins K, Kodali S, Nunez L, Prasad AK, Phelan LM, Ammirati M, Yu X, Lees JA, Chen W, Martinez L, Roopchand V, Han S, Qiu X, DeVincenzo JP, Jansen KU, Dormitzer PR, and Swanson KA
- Subjects
- Pregnancy, Female, Humans, Animals, Antibodies, Viral, Antibodies, Neutralizing, Glycoproteins, Sigmodontinae, Viral Fusion Proteins genetics, Respiratory Syncytial Virus Vaccines, Respiratory Syncytial Virus Infections prevention & control, Respiratory Syncytial Virus, Human genetics
- Abstract
Respiratory syncytial virus (RSV) is the leading, global cause of serious respiratory disease in infants and is an important cause of respiratory illness in older adults. No RSV vaccine is currently available. The RSV fusion (F) glycoprotein is a key antigen for vaccine development, and its prefusion conformation is the target of the most potent neutralizing antibodies. Here, we describe a computational and experimental strategy for designing immunogens that enhance the conformational stability and immunogenicity of RSV prefusion F. We obtained an optimized vaccine antigen after screening nearly 400 engineered F constructs. Through in vitro and in vivo characterization studies, we identified F constructs that are more stable in the prefusion conformation and elicit ~10-fold higher serum-neutralizing titers in cotton rats than DS-Cav1. The stabilizing mutations of the lead construct (847) were introduced onto F glycoprotein backbones of strains representing the dominant circulating genotypes of the two major RSV subgroups, A and B. Immunization of cotton rats with a bivalent vaccine formulation of these antigens conferred complete protection against RSV challenge, with no evidence of disease enhancement. The resulting bivalent RSV prefusion F investigational vaccine has recently been shown to be efficacious against RSV disease in two pivotal phase 3 efficacy trials, one for passive protection of infants by immunization of pregnant women and the second for active protection of older adults by direct immunization.
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- 2023
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33. Assessing the Utility of ChatGPT Throughout the Entire Clinical Workflow.
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Rao A, Pang M, Kim J, Kamineni M, Lie W, Prasad AK, Landman A, Dreyer KJ, and Succi MD
- Abstract
Importance: Large language model (LLM) artificial intelligence (AI) chatbots direct the power of large training datasets towards successive, related tasks, as opposed to single-ask tasks, for which AI already achieves impressive performance. The capacity of LLMs to assist in the full scope of iterative clinical reasoning via successive prompting, in effect acting as virtual physicians, has not yet been evaluated., Objective: To evaluate ChatGPT's capacity for ongoing clinical decision support via its performance on standardized clinical vignettes., Design: We inputted all 36 published clinical vignettes from the Merck Sharpe & Dohme (MSD) Clinical Manual into ChatGPT and compared accuracy on differential diagnoses, diagnostic testing, final diagnosis, and management based on patient age, gender, and case acuity., Setting: ChatGPT, a publicly available LLM., Participants: Clinical vignettes featured hypothetical patients with a variety of age and gender identities, and a range of Emergency Severity Indices (ESIs) based on initial clinical presentation., Exposures: MSD Clinical Manual vignettes., Main Outcomes and Measures: We measured the proportion of correct responses to the questions posed within the clinical vignettes tested., Results: ChatGPT achieved 71.7% (95% CI, 69.3% to 74.1%) accuracy overall across all 36 clinical vignettes. The LLM demonstrated the highest performance in making a final diagnosis with an accuracy of 76.9% (95% CI, 67.8% to 86.1%), and the lowest performance in generating an initial differential diagnosis with an accuracy of 60.3% (95% CI, 54.2% to 66.6%). Compared to answering questions about general medical knowledge, ChatGPT demonstrated inferior performance on differential diagnosis (β=-15.8%, p<0.001) and clinical management (β=-7.4%, p=0.02) type questions., Conclusions and Relevance: ChatGPT achieves impressive accuracy in clinical decision making, with particular strengths emerging as it has more clinical information at its disposal.
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- 2023
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34. Spectroscopic determination of the role of vanadyl oxygen in room temperature NH 3 sensing by V 2 O 5 nanoparticles.
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Radhakrishnan RP and Prasad AK
- Abstract
In the present study, a multi-modal approach consisting of in-situ photoluminescence, Raman, and UV-Vis absorption spectroscopic studies is carried out along with chemiresistive sensing to unveil the mechanism of NH
3 gas sensing by V2 O5 nanoparticles in ambient air. V2 O5 nanoparticles with an average size of 49 nm show a superior sensor response of 17 ± 1.5 % towards 1 ppm of NH3 gas with a response and recovery time of 96 s and 45 s, respectively. The photoluminescence and UV-Vis absorption studies in the presence of NH3 reveal electron doping to a new energy level at 1.84 eV, resulting in conduction band filling and increase in the optical band gap. The intensity of the photoluminescence spectrum shows an increase in the presence of NH3 gas as a result of this electron doping. The sensor response from the optical sensing carried out by in-situ photoluminescence study is 43 % for 40 ppm of NH3 gas. The vanadyl oxygen site is the most active in the sensing process, as evident by a selective enhancement in the intensity of V-O (vanadyl) bond vibration. This study gives an experimental evidence for the changes in optical and electronic properties of V2 O5 on the adsorption of NH3 gas molecules., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)- Published
- 2023
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35. Immune-modulation by 7, 8-diacetoxy-4-methylthiocoumarin in total body-irradiated mice: Implications for the mitigation of radiation-induced hematopoietic injury.
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Venkateswaran K, Shrivastava A, Agrawala PK, Prasad AK, Manda K, Parmar VS, and Dwarakanath BS
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- Mice, Animals, Mice, Inbred C57BL, Whole-Body Irradiation, Bone Marrow radiation effects, Cytokines, Radiation Injuries
- Abstract
Aims: Development of novel medical countermeasures (MCMs) against acute radiation syndrome (ARS) and the associated lethality involves protection from and/or mitigation of radiation-induced hematopoietic injury, a critical clinical component of ARS. We earlier identified the molecule 7,8-diacetoxy-4-methylthiocoumarin (DAMTC) as a potent mitigator of hematopoietic injury and mortality in C57BL/6 mice when administered 24 h following total body irradiation (TBI). In the present study, we investigated mechanisms and functional relevance of immune modulation by DAMTC during the mitigation of hematopoietic injury., Main Methods: C57BL/6 mice were subjected to TBI doses of 3 and 7.6Gy; administered DAMTC intra-peritoneally 24 h post TBI. Isolation, characterization, intra-cellular cytokine analysis of myeloid cells from bone marrow and spleen accompanied by flow cytometric determination and characterization of B-lymphocytes, serum isolation from peripheral blood and cytokine analysis., Key Findings: Results showed that DAMTC induced stimulation of pro-inflammatory myeloid subsets in the bone marrow and spleen of TBI mice. Further, it promoted a favorable transition from Th2 to Th1 immunity, triggered humoral immunity, and activated an intricately balanced inflammatory response that appear to contribute to immune-modulation., Significance: Thus, the present study shows that immune-modulation maybe one of the contributing factors for the mitigation of hematopoietic injury by DAMTC and underscores its efficacy as a potent mitigator of hematopoietic injury that merits to be developed further as a novel MCM to combat H-ARS., Competing Interests: Declaration of competing interest The authors declare that they have no competing interests., (Copyright © 2022 Elsevier Inc. All rights reserved.)
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- 2022
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36. Transition metal-catalyzed double C vinyl -H bond activation: synthesis of conjugated dienes.
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Maikhuri VK, Maity J, Srivastava S, and Prasad AK
- Subjects
- Catalysis, Polyenes, Oxidation-Reduction, Alkenes chemistry, Transition Elements
- Abstract
Conjugated dienes have occupied a pivotal position in the field of synthetic organic chemistry and medicinal chemistry. They act as important synthons for the synthesis of various biologically important molecules and therefore, gain tremendous attention worldwide. A wide range of synthetic routes to access these versatile molecules have been developed in the past decades. Transition metal-catalyzed cross-dehydrogenative coupling (CDC) has emerged as one of the utmost front-line research areas in current synthetic organic chemistry due to its high atom economy, efficiency, and viability. In this review, an up-to-date summary including scope, limitations, mechanistic studies, stereoselectivities, and synthetic applications of transition metal-catalyzed double C
vinyl -H bond activation for the synthesis of conjugated dienes has been reported since 2013. The literature reports mentioned in this review have been classified into three different categories, i.e. (a) Cvinyl -Cvinyl bond formation via oxidative homo-coupling of terminal alkenes; (b) Cvinyl -Cvinyl bond formation via non-directed oxidative cross-coupling of linear/cyclic alkenes and terminal/internal alkenes, and (c) Cvinyl -Cvinyl bond formation via oxidative cross-coupling of directing group bearing alkenes and terminal/internal alkenes. Overall, this review aims to provide a concise overview of the current status of the considerable development in this field and is expected to stimulate further innovation and research in the future.- Published
- 2022
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37. Radiosensitization of calreticulin-overexpressing human glioma cell line by the polyphenolic acetate 7, 8-diacetoxy-4-methylcoumarin.
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Verma A, Arora A, Bhatt AN, Arya MB, Prasad AK, Parmar VS, and Dwarakanath BS
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- Humans, Cell Line, Acetates pharmacology, Calreticulin genetics, Calreticulin metabolism, Glioma drug therapy, Glioma metabolism, Polyphenols pharmacology, Coumarins pharmacology, Radiation-Sensitizing Agents pharmacology, Radiation Tolerance drug effects
- Abstract
Background: Calreticulin (CRT), an endoplasmic reticulum-resident protein generally overexpressed in cancer cells, is associated with radiation resistance. CRT shows higher transacetylase activity, as shown by us earlier, in the presence of the polyphenolic acetates (like 7, 8-diacetoxy-4-methylcoumarin, DAMC) and modifies the activity of a number of proteins, thereby influencing cell signaling., Aim: To investigate the relationship between CRT expression and radiation response in a human glioma cell line and to evaluate the radiomodifying effects of DAMC., Methods and Results: Studies were carried out in an established human glioma cell line (BMG-1) and its isogenic clone overexpressing CRT (CROE, CRT-overexpressing cells) by analyzing clonogenic survival, cell proliferation, micronuclei analysis, and protein levels by Western blotting as parameters of responses. CRT overexpression conferred resistance against radiation-induced cell death in CROE cells (D
37 = 7.35 Gy, D10 = 12.6 Gy and D0 = 7.25 Gy) as compared to BMG-1 cells (D37 = 5.70 Gy, D10 = 9.2 Gy and D0 = 5.6 Gy). A lower level of radiation-induced micronuclei formation observed in CROE cells suggested that reduced induction and/or enhanced DNA repair partly contributed to the enhanced radioresistance. Consistent with this suggestion, we noted that CRT-mediated radioresistance was coupled with enhanced grp78 level and reduced P53 activation-mediated prodeath signaling, while no changes were noted in acetylation of histone H4. DAMC-enhanced radiation-induced delayed (secondary) apoptosis, which was higher in CROE cells., Conclusion: CRT overexpression confers resistance against radiation-induced death of human glioma cells, which can be overcome by the polyphenolic acetate DAMC., (© 2021 The Authors. Cancer Reports published by Wiley Periodicals LLC.)- Published
- 2022
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38. Streptococcus pneumoniae serotype 15B polysaccharide conjugate elicits a cross-functional immune response against serotype 15C but not 15A.
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Hao L, Kuttel MM, Ravenscroft N, Thompson A, Prasad AK, Gangolli S, Tan C, Cooper D, Watson W, Liberator P, Pride MW, Jansen KU, Anderson AS, and Scully IL
- Subjects
- Aged, Antibodies, Bacterial, Humans, Immunity, Pneumococcal Vaccines, Polysaccharides, Serogroup, Vaccines, Conjugate, Pneumococcal Infections prevention & control, Streptococcus pneumoniae
- Abstract
Protection conferred by pneumococcal polysaccharide conjugate vaccines (PCVs) is associated with PCV-induced antibodies against vaccine-covered serotypes that exhibit functional opsonophagocytic activity (OPA). Structural similarity between capsular polysaccharides of closely related serotypes may result in induction of cross-reactive antibodies with or without a cross-functional activity against a serotype not covered by a PCV, with the former providing an additional protective clinical benefit. Serotypes 15B, 15A, and 15C, in the serogroup 15, are among the most prevalent Streptococcus pneumoniae serotypes associated with invasive pneumococcal disease following the implementation of a 13-valent PCV; in addition, 15B contributes significantly to acute otitis media. Serological discrimination between closely related serotypes such as 15B and 15C is complicated; here, we implemented an algorithm to quickly differentiate 15B from its closely related serotypes 15C and 15A directly from whole-genome sequencing data. In addition, molecular dynamics simulations of serotypes 15A, 15B, and 15C polysaccharides demonstrated that while 15B and 15C polysaccharides assume rigid branched conformation, 15A polysaccharide assumes a flexible linear conformation. A serotype 15B conjugate, included in a 20-valent PCV (PCV20), induced cross-functional OPA serum antibody responses against the structurally similar serotype 15C but not against serotype 15A, both not included in PCV20. In PCV20-vaccinated adults (18-49 years), robust OPA antibody titers were detected against both serotypes 15B (the geometric mean titer [GMT] of 19,334) and 15C (GMTs of 1692 and 2747 for strains PFE344340 and PFE1160, respectively), but were negligible against serotype 15A (GMTs of 10 and 30 for strains PFE593551 and PFE647449, respectively). Cross-functional 15B/C responses were also confirmed using sera from a larger group of older adults (60-64 years)., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: [Ingrid Scully, Li Hao, Allison Thompson, Seema Gangolli, Charles Tan, David Cooper, Wendy Watson, Paul Liberator, Michael Pride, Kathrin Jansen and Annaliesa Anderson are all employees of Pfizer and as such may hold stock and stock options. A. Krishna Prasad was an employee of Pfizer at the time the work was conducted but has since left the company. Michelle M. Kuttel reports a relationship with Pfizer Inc that includes: funding grants. Neil Ravenscroft reports a relationship with Pfizer Inc that includes: funding grants.]., (Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)
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- 2022
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39. Preclinical Immunogenicity and Efficacy of Optimized O25b O-Antigen Glycoconjugates To Prevent MDR ST131 E. coli Infections.
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Chorro L, Li Z, Chu L, Singh S, Gu J, Kim JH, Dutta K, Pan R, Kodali S, Ndreu D, Patel A, Hawkins JC, Ponce C, Silmon de Monerri N, Keeney D, Illenberger A, Jones CH, Andrew L, Lotvin J, Prasad AK, Kanevsky I, Jansen KU, Anderson AS, and Donald RGK
- Subjects
- Animals, Carrier Proteins, Escherichia coli, Glycoconjugates, Mice, Escherichia coli Infections prevention & control, O Antigens
- Abstract
Multivalent O-antigen polysaccharide glycoconjugate vaccines are under development to prevent invasive infections caused by pathogenic Enterobacteriaceae . Sequence type 131 (ST131) Escherichia coli of serotype O25b has emerged as the predominant lineage causing invasive multidrug-resistant extraintestinal pathogenic E. coli (ExPEC) infections. We observed the prevalence of E. coli O25b ST131 among a contemporary collection of isolates from U.S. bloodstream infections from 2013 to 2016 ( n = 444) and global urinary tract infections from 2014 to 2017 ( n = 102) to be 25% and 24%, respectively. To maximize immunogenicity of the serotype O25b O antigen, we investigated glycoconjugate properties, including CRM
197 carrier protein cross-linking (single-end versus cross-linked "lattice") and conjugation chemistry (reductive amination chemistry in dimethyl sulfoxide [RAC/DMSO] versus ((2-((2-oxoethyl)thio)ethyl)carbamate [eTEC] linker). Using opsonophagocytic assays (OPAs) to measure serum functional antibody responses to vaccination, we observed that higher-molecular-mass O25b long-chain lattice conjugates showed improved immunogenicity in mice compared with long- or short-chain O antigens conjugated via single-end attachment. The lattice conjugates protected mice from lethal challenge with acapsular O25b ST131 strains as well as against hypervirulent O25b isolates expressing K5 or K100 capsular polysaccharides. A single 1-μg dose of long-chain O25b lattice conjugate constructed with both chemistries also elicited robust serum IgG and OPA responses in cynomolgus macaques. Our findings show that key properties of the O-antigen carrier protein conjugate such as saccharide epitope density and degree of intermolecular cross-linking can significantly enhance functional immunogenicity.- Published
- 2022
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40. Presence of Resistant DEC Strains in a Tertiary Healthcare Center in North East India in Children under 18 Years.
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Prasad AK, Lyngdoh WV, Devi TS, and Durairaj E
- Abstract
Introduction Diarrheal illness such as diarrheagenic Escherichia coli (DEC), apart from rotavirus, is a common etiological agent known to cause moderate-to-severe diarrhea in low-income countries where unregulated use of antibiotics is rampant, giving rise to multidrug resistant (MDR) strains. This study is an earnest effort in reflecting the resistance pattern in such isolates. Materials and Methods It is a hospital-based cross-sectional study conducted over a period of 1 year (January to December, 2015). Children aged less than 18 years presenting with ( n = 170) and without ( n = 47) diarrhea were included as cases and controls, respectively. Fresh stool sample from eligible participants was collected and inoculated on MacConkey agar. Based on the colony morphology and biochemical identification followed by polymerase chain reaction (PCR), different pathotypes of DEC were identified. All such isolates were subjected to antimicrobial susceptibility testing employing VITEK 2 identification system. The result of the tested antibiotics was evaluated as per Clinical and Laboratory Standards Institute 2015 guidelines. Results DEC with specific virulence genes were detected by multiplex real-time PCR in 39 and 3 children with or without diarrhea, respectively. Most common DEC pathotypes found were enteroaggregative E. coli (38%) followed by enteropathogenic E. coli (28.5%). MDR isolates comprised 35 of 42 DEC pathotypes (83.3%). Resistance among DEC pathotypes to ampicillin, amoxicillin-clavulanate, ciprofloxacin, cephalosporin, nalidixic acid, imipenem, and cotrimoxazole was found to be statistically significant in comparison to non-DEC isolates. Conclusion This study has highlighted the increased prevalence of MDR strains among DEC pathotypes. Looking for these isolates will help detect dreadful DEC pathotypes like enterohemorrhagic E. coli where early administration of a sensitive antibiotic will go a long way in preventing complication like hemorrhagic colitis and hemolytic uremic syndrome., Competing Interests: Conflicts of Interest None declared., (The Indian Association of Laboratory Physicians. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. ( https://creativecommons.org/licenses/by-nc-nd/4.0/ ).)
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- 2022
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41. Chemical and chemoenzymatic routes to bridged homoarabinofuranosylpyrimidines: Bicyclic AZT analogues.
- Author
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Kumar S, Maity J, Kumar B, Kumar S, and Prasad AK
- Abstract
Conformationally restricted diastereomeric homoarabinofuranosylpyrimidines (AZT analogue), i.e., (5' R )-3'-azido-3'-deoxy-2'- O ,5'- C -bridged-β-ᴅ-homoarabinofuranosylthymine and -uracil had been synthesized starting from diacetone ᴅ-glucofuranose following chemoenzymatic and chemical routes in 34-35% and 24-25% overall yields, respectively. The quantitative and diastereoselective acetylation of primary hydroxy over two secondary hydroxy groups present in the key nucleoside precursor was mediated with Lipozyme
® TL IM in 2-methyltetrahydrofuran following a chemoenzymatic pathway. Whereas, the protection of the primary hydroxy over the lone secondary hydroxy group in the key azido sugar precursor was achieved using bulky tert -butyldiphenylsilyl chloride (TBDPS-Cl) in pyridine in 92% yield following a chemical synthetic pathway. The chemoenzymatic method was found to be superior over the chemical method in respect of the number of synthetic steps and overall yield of the final product., (Copyright © 2022, Kumar et al.)- Published
- 2022
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42. Secondary Structure Transitions for a Family of Amyloidogenic, Antimicrobial Uperin 3 Peptides in Contact with Sodium Dodecyl Sulfate.
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Prasad AK, Tiwari C, Ray S, Holden S, Armstrong DA, Rosengren KJ, Rodger A, Panwar AS, and Martin LL
- Subjects
- Australia, Peptides, Sodium Dodecyl Sulfate, Anti-Infective Agents, Antimicrobial Peptides
- Abstract
Secondary structure changes are an inherent part of antimicrobial (AMP) and amyloidogenic peptide activity, especially in close proximity to membranes, and impact the peptides' function and dysfunction roles. The formation, and stability of α-helical components are regarded as essential 'intermediates' for both these functions. To illuminate the conformational transitions leading to amyloid formation we use short cationic AMPs, from an Australian toadlet, Uperoleia mjobergii, (Uperin 3 family, U3) and assess the impact on secondary structural elements in the presence of a membrane mimetic surfactant, sodium dodecyl sulfate (SDS). Specifically, Uperin 3.x, where x=4, 5, 6 wild-type peptides and position seven variants for each, R7A or K7A, were investigated using a combination of experimental and simulation approaches. In water, U3 peptides remain largely unstructured as random coils, with the addition of salts initiating structural transitions leading to assembly towards amyloid. Solution NMR data show that an unstructured U3.5 wt peptide transitions in the presence of SDS to a well-defined α-helical structure that spans nearly the entire sequence. Circular dichroism (CD) and ThT fluorescence studies show that all six U3 peptides aggregate in solution, albeit with vastly varying rates, and a dynamic equilibrium between soluble aggregates rich in either α-helices or β-sheets may exist in solution. However, the addition of SDS leads to a rapid disaggregation for all peptides and stabilisation of predominantly α-helical content in all the U3 peptides. Molecular dynamics (MD) simulations show that the adsorption of U3.5 wt/R7A peptides onto the SDS micelle is driven by Coulombic attraction between peptide cationic residues and the negatively charged sulfate head-groups on SDS. Simulating the interactions of various kinds of β-sheet dimers (of both U3.5 wt and its variant U3.5 R7A) with SDS micelles confirmed β-sheet content decreases in the dimers after their attachment to the SDS micelle. Adsorbed peptides interact favourably with the hydrophobic core of the micelle, promoting intramolecular hydrogen bonds leading to stabilisation of the α-helical structure in peptides, and resulting in a corresponding decrease in intermolecular hydrogen bonds responsible for β-sheets., (© 2022 Wiley-VCH GmbH.)
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- 2022
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43. Synthesis and applications of bicyclic sugar modified locked nucleic acids: A review.
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Goswami A, Prasad AK, Maity J, and Khaneja N
- Subjects
- Carbohydrates, Nucleic Acid Conformation, Oligonucleotides, Antisense, Oligonucleotides, Sugars
- Abstract
A large number of Locked Nucleic Acids (LNAs) with variety of modifications and restricted conformations have been developed in the last few decades. These modifications have significantly improved the biological properties of oligonucleotides, when LNAs moieties were incorporated into them. Herein, the synthesis and applications of these modified locked nucleic acids as antisense oligonucleotides are discussed.Supplemental data for this article is available online at https://doi.org/10.1080/15257770.2022.2052316 .
- Published
- 2022
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44. A study on viral haemorrhagic fever due to dengue, chikungunya and Crimean Congo haemorrhagic fever virus among patients attending tertiary care hospital in North East India.
- Author
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Prasad AK, Phukan AC, and Barman B
- Subjects
- Animals, Antibodies, Viral, Cattle, Humans, Seroepidemiologic Studies, Sheep, Tertiary Care Centers, Chikungunya Fever diagnosis, Chikungunya Fever epidemiology, Dengue diagnosis, Dengue epidemiology, Hemorrhagic Fever Virus, Crimean-Congo genetics, Hemorrhagic Fever, Crimean diagnosis, Hemorrhagic Fever, Crimean epidemiology
- Abstract
Purpose: The present study was undertaken with the objective to study the common etiology of Viral Haemorrhagic Fever (VHF) among patients attending tertiary health care centre in NE India and also to study the clinico-demographic profile of such patients. The agents of VHF included in the study were dengue, chikungunya and Crimean Congo haemorrhagic fever (CCHF) virus. The inclusion of CCHF was based on evidence of seroprevalence in livestock (bovine, sheep and goat) in various North Eastern states., Materials and Methods: Serum samples were collected from 51 suspected VHF patients. MAC-ELISA was done to detect dengue and chikungunya specific IgM antibody. The samples were also tested by real-time RT-PCR for detection of dengue, chikungunya and CCHF specific nucleic acid. The laboratory and clinico-demographic profile of these patients were noted in detail., Results: Serum samples of 16 of 51 suspected cases were confirmed to be suffering from VHF. Among these confirmed cases, 12 were diagnosed with dengue haemorrhagic fever, one was diagnosed with chikungunya and three were diagnosed with dengue-chikungunya co-infection. Based on severity, DHF was further classified into- DHF I- (4,26.6%), DHF II (6,40%), DHF III (3,20%) and DHF IV (2,13.3%). There was no CCHFV infection detected in our study. Retro-orbital pain (P = 0.02) and haematocrit level (P = 0.03) were found to be statistically significant., Conclusions: This study reiterates the fact that CCHF virus infection is still probably absent in human population of NE India and haemorrhagic symptoms, though rare maybe one of the atypical manifestations of chikungunya infection., Competing Interests: Declaration of competing interest None., (Copyright © 2021 Indian Association of Medical Microbiologists. Published by Elsevier B.V. All rights reserved.)
- Published
- 2022
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45. Microwave Assisted Cu-Mediated Trifluoromethylation of Pyrimidine Nucleosides.
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Mangla P, Sanghvi YS, and Prasad AK
- Subjects
- Antiviral Agents, Microwaves, Nucleosides, Pyrimidine Nucleosides
- Abstract
Trifluoromethylated nucleosides, such as trifluridine, have widespread applications in pharmaceuticals as anticancer and antiviral agents. However, site-selective addition of a trifluoromethyl group onto a nucleobase typically requires either inconvenient multi-step synthesis or expensive trifluoromethylation reagents, or results in low yield. This article describes a simple, scalable, and high-yielding protocol for late-stage direct trifluoromethylation of pyrimidine nucleosides via a microwave-irradiated pathway. First, 5-iodo pyrimidine nucleosides undergo complete benzoylation to obtain N
3 -benzoyl-3',5'-di-O-benzoyl-5-iodo-pyrimidine nucleosides as key precursors. Next, trifluoromethylation is carried out under both conventional and microwave heating using an inexpensive and commercially accessible Chen's reagent, i.e., methyl fluorosulfonyldifluoroacetate, to produce N3 -benzoyl-3',5'-di-Obenzoyl-5-trifluoromethyl-pyrimidine nucleosides. The microwave-assisted transformation accentuates its simplicity, mild reaction conditions, and dominance, providing a facile route to access trifluoromethylation. Finally, the envisioned 5-trifluoromethyl pyrimidine nucleosides are obtained by a routine debenzoylation procedure. This concludes a convenient three-step synthesis to obtain trifluridine and its 2'-modified analogs on a gram scale with consistently high yields, starting from their respective iodo-precursors, and requires only one chromatographic purification at the trifluoromethylation step. Furthermore, this operationally simple protocol can be utilized as a definitive methodology to produce various other trifluoromethylated therapeutics. © 2021 Wiley Periodicals LLC. Basic Protocol: Synthesis of 5-trifluoromethyl pyrimidine nucleosides 4a-c Alternate Protocol: Conventional trifluoromethylation: Synthesis of N3-benzoyl-3',5'-di-O-benzoyl-5-trifluoromethyl pyrimidine nucleosides (3a-c)., (© 2021 Wiley Periodicals LLC.)- Published
- 2021
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46. Effects of excessive use of mobile phone technology in India on human health during COVID-19 lockdown.
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Tyagi A, Prasad AK, and Bhatia D
- Abstract
Objective: The global health crisis in the form of COVID-19 has forced people to shift their routine activities into a remote environment with the help of technology. The outbreak of the COVID-19 has caused several organizations to be shut down and forced them to initiate work from home employing technology. Now more than ever, it's important for people and institutions to understand the impact of excessive use of mobile phone technology and electronic gadgets on human health, cognition, and behavior. It is important to understand their perspective and how individuals are coping with this challenge in the wake of the COVID-19 pandemic. The investigation is an effort to answer the research question: whether dependency on technology during lockdown has more effects on human health in comparison to normal times., Methods: The study included participants from India (n = 122). A questionnaire was framed and the mode of conducting the survey chosen was online to maintain social distancing during the time of the Pandemic. The gathered data was statistically analysed employing RStudio and multiple regression techniques., Results: The statistical analysis confirms that lockdown scenarios have led to an increase in the usage of mobile phone technology which has been confirmed by around 90% of participants. Moreover, 95% of the participants perceive an increased risk of developing certain health problems due to excessive usage of mobile phones and technology. It has been evaluated that participants under the age group 15-30 years are highly affected (45.9%) during lockdown due to excessive dependence on technology. And, amongst different professions, participants involved in online teaching-learning are the most affected (42.6%)., Conclusion: The findings indicate that dependency on technology during lockdown has more health effects as compared to normal times. So, it is suggested that as more waves of pandemics are being predicted, strategies should be planned to decrease the psychological and physiological effects of the overuse of technology during lockdown due to pandemics. As the lockdown situation unfolds, people and organization functioning styles should be rolled back to the limited dependency on technology., (© 2021 Elsevier Ltd. All rights reserved.)
- Published
- 2021
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47. Electronic and Vibrational Decoupling in Chemically Exfoliated Bilayer Thin Two-Dimensional V 2 O 5 .
- Author
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P R R, Pazhedath A, Sinha SK, Dasgupta A, Karuppiah G, Prasad AK, and Dhara S
- Abstract
The synthesis of high-quality two-dimensional (2D) transition metal oxides is challenging compared to 2D transition metal dichalcogenides as a result of the exotic surface changes that can appear during formation. Herein, we report the synthesis of bilayer 2D V
2 O5 nanosheets with a thickness of ∼1 nm using the chemical exfoliation method and a comprehensive study on the vibrational and optical properties of bilayer 2D V2 O5 . We report, for the first time, a thickness-dependent blue shift of 1.33 eV in the optical bandgap, which signifies the emergence of electronic decoupling in bilayer 2D V2 O5 . In addition, a thickness-dependent vibrational decoupling of phonon modes observed via Raman spectroscopy fingerprinting was verified by computing the lattice vibrational modes using the density functional perturbation theory. We demonstrate that the manifestation of the electronic and vibrational decoupling can be used as a benchmark to confirm the successful formation of bilayer 2D V2 O5 from its bulk counterpart.- Published
- 2021
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48. Evaluation of the Free Radical Scavenging Activities of Ellagic Acid and Ellagic Acid Peracetate by EPR Spectrometry.
- Author
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Kumar A, Kaushik P, Incerpi S, Pedersen JZ, Goel S, Prasad AK, Rohil V, Parmar VS, Saso L, and Len C
- Subjects
- Animals, Rats, Electron Spin Resonance Spectroscopy methods, Reactive Oxygen Species metabolism, Microsomes, Liver metabolism, Cell Line, Myoblasts metabolism, Myoblasts drug effects, Kinetics, Ellagic Acid pharmacology, Ellagic Acid chemistry, Ellagic Acid metabolism, Lipid Peroxidation drug effects, Free Radical Scavengers chemistry, Free Radical Scavengers pharmacology
- Abstract
The purpose of this study was to examine the free radical scavenging and antioxidant activities of ellagic acid (EA) and ellagic acid peracetate (EAPA) by measuring their reactions with the radicals, 2,2-diphenyl-1-picrylhydrazyl and galvinoxyl using EPR spectroscopy. We have also evaluated the influence of EA and EAPA on the ROS production in L-6 myoblasts and rat liver microsomal lipid peroxidation catalyzed by NADPH. The results obtained clearly indicated that EA has tremendous ability to scavenge free radicals, even at concentration of 1 µM. Interestingly even in the absence of esterase, EAPA, the acetylated product of EA, was also found to be a good scavenger but at a relatively slower rate. Kinetic studies revealed that both EA and EAPA have ability to scavenge free radicals at the concentrations of 1 µM over extended periods of time. In cellular systems, EA and EAPA were found to have similar potentials for the inhibition of ROS production in L-6 myoblasts and NADPH-dependent catalyzed microsomal lipid peroxidation.
- Published
- 2021
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49. Gas sensing materials roadmap.
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Wang H, Ma J, Zhang J, Feng Y, Vijjapu MT, Yuvaraja S, Surya SG, Salama KN, Dong C, Wang Y, Kuang Q, Tshabalala ZP, Motaung DE, Liu X, Yang J, Fu H, Yang X, An X, Zhou S, Zi B, Liu Q, Urso M, Zhang B, Akande AA, Prasad AK, Hung CM, Van Duy N, Hoa ND, Wu K, Zhang C, Kumar R, Kumar M, Kim Y, Wu J, Wu Z, Yang X, Vanalakar SA, Luo J, Kan H, Li M, Jang HW, Orlandi MO, Mirzaei A, Kim HW, Kim SS, Uddin ASMI, Wang J, Xia Y, Wongchoosuk C, Nag A, Mukhopadhyay S, Saxena N, Kumar P, Do JS, Lee JH, Hong S, Jeong Y, Jung G, Shin W, Park J, Bruzzi M, Zhu C, Gerald RE 2nd, and Huang J
- Abstract
Gas sensor technology is widely utilized in various areas ranging from home security, environment and air pollution, to industrial production. It also hold great promise in non-invasive exhaled breath detection and an essential device in future internet of things. The past decade has witnessed giant advance in both fundamental research and industrial development of gas sensors, yet current efforts are being explored to achieve better selectivity, higher sensitivity and lower power consumption. The sensing layer in gas sensors have attracted dominant attention in the past research. In addition to the conventional metal oxide semiconductors, emerging nanocomposites and graphene-like two-dimensional materials also have drawn considerable research interest. This inspires us to organize this comprehensive 2020 gas sensing materials roadmap to discuss the current status, state-of-the-art progress, and present and future challenges in various materials that is potentially useful for gas sensors., (© 2021 IOP Publishing Ltd.)
- Published
- 2021
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50. Double-headed nucleosides: Synthesis and applications.
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Verma V, Maity J, Maikhuri VK, Sharma R, Ganguly HK, and Prasad AK
- Abstract
Double-headed nucleoside monomers have immense applications for studying secondary nucleic acid structures. They are also well-known as antimicrobial agents. This review article accounts for the synthetic methodologies and the biological applications of double-headed nucleosides., (Copyright © 2021, Verma et al.)
- Published
- 2021
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