Browsing by Author "Varsha Singh"

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A Co and Fe bimetallic MOF with enhanced electrocatalytic oxygen evolution performance: exploring the electronic environment modifications upon Fe incorporation
(Royal Society of Chemistry, 2024) Varsha Singh; Devesh Kumar Singh; Mamta Yadav; Smita Singh; Vikram Rathour; Ananya Tiwari; Vellaichamy Ganesan
The incorporation of iron into the cobalt-based metal-organic framework (Co-MOF) modifies the electronic environment and the resulting bimetallic MOF exhibits enhanced oxygen evolution reaction (OER) performance. The Co-MOF, Fe-MOF, and different ratios of bimetallic Co-Fe-MOFs are prepared using 2,2′-bipyridine 4,4′-dicarboxylic acid (H2bpdc) by a single-step hydrothermal process. The MOFs are evaluated by necessary spectroscopy and microscopy techniques like Fourier transform infrared spectroscopy, inductively coupled plasma emission spectroscopy, powder X-ray diffraction, transmission electron microscopy, energy-dispersive X-ray analysis, and X-ray photoelectron spectroscopy. The incorporation of Fe3+ into the Co-MOF significantly increases the electrocatalytic activity of the resulting bimetallic Co-Fe-MOF towards the OER. An optimized bimetallic MOF having a Co : Fe ratio of 2 : 1 shows the lowest overpotential (310 mV) to realize the 10 mA cm−2 current density and the lowest Tafel slope of 53 mV dec−1 with excellent durability in comparison to the Co-MOF, the Fe-MOF, and the state-of-the-art catalyst, RuO2. Furthermore, this manuscript addresses the inherent electrocatalytic properties of MOF-based electrocatalysts and demonstrates their possible exploitation in water electrolysis. © 2024 RSC.
Carbon-Based Nanomaterials and Their Green Energy Applications: Carbon Nanotubes
(wiley, 2024) Smita Singh; Varsha Singh; Vikram Rathour; Vellaichamy Ganesan
In today’s world, the rapid exhaustion of non-renewable energy sources has led to a significant surge in renewable and green energy alternatives. Electrochemical devices are considered to be one of the reliable alternatives. Carbon-based nanostructures, including graphene, carbon nanotubes (CNTs), and similar materials have drawn substantial interest owing to their distinct physicochemical and electrical properties, which render them promising candidates for green energy applications. With the first finding of CNTs by Iijima in 1991, they are exploited in many fields. CNTs are the one-dimensional allotrope of carbon, possessing long hollow tube-like structures made up of sp2carbon having a diameter of nanoscale range and length in micrometers. On the basis of the number of tubes in their structure, they can be either single-or multi-walled CNTs (SWCNTs and MWCNTs, respectively). They have grabbed the interest of researchers owing to their unique chemical composition and many alluring properties like high conductivity, huge mechanical strength, and large surface area. Numerous carbon-based nanomaterials exhibit fascinating structure-property relationships, but it is the CNTs that have garnered the most intense research focus. Owing to such unique properties, CNTs have been utilized either directly as the electrode material or as a support in almost all the fields of electrochemistry: be it sensing, energy conversion, or energy storage applications. CNTs have demonstrated promising results in enhancing the proficiency of energy conversion and storage strategies, thereby contributing to the advancement of green energy innovations. In this chapter, the synthesis, characterization, and unique properties of CNTs are delved. Moreover, its vital role in various green energy applications, specifically in the areas of oxygen electrocatalysis and supercapacitors, is comprehensively discussed. © 2025 by The Institute of Electrical and Electronics Engineers, Inc. All rights reserved.
Comparative Study of Crossability Behavior in Intra-specific and Inter-specific Crosses of Vigna radiata and Vigna mungo
(Agricultural Research Communication Centre, 2023) Varsha Singh; Anil Kumar Singh; Mahendra Narain Singh; Brajesh Sinha
Background: The basic plant material consisted of 9 mungbean and 5 urdbean genotypes. 42 different crosses were made comprising 13 Vigna radiata ´ V. radiata, 4 V. radiata ´ V. mungo and 25 V. radiata ´ V. mungo crosses. Varying degree of success has been achieved in obtaining intraspecific and interspecific crosses having desired variability for yield and yield contributing traits along with MYMV resistance. Methods: The present investigation was done at Agricultural Research Farm, Banaras Hindu University, Varanasi, during Kharif, 2019 and Summer, 2020. 42 intra-specific and inter-specific cross combinations were initially examined for their crossability. Out of these, six promising crosses with higher crossability percent were further analyzed for hybrid pollen fertility, hybrid lethality and, evaluation of F1 and parents for different yield traits. Result: Crossability per cent found highest in intraspecific cross HUM 2 ´ IPM 02-3 (41.86%) in mungbean while, in urdbean cross NDU 1 ´ R3/12 (41.38%). In interspecific crosses, the maximum crossability per cent was found in SKAU M 365 ´ R3/28 (34.92%). Two mungbean genotypes (HUM 2 and HUM 26) and two urdbean genotypes (R3/12 and R3/28) can be further utilized for genetic improvement through inter-specific hybridization as there cross combinations are better performing on the basis of yield attributes along with MYMV resistance. © 2023, Agricultural Research Communication Centre. All rights reserved.
Detection of Helicobacter pylori in stool specimens: comparative evaluation of nested PCR and antigen detection.
(2008) Shrutkirti Mishra; Varsha Singh; G R Koteswar Rao; Ashok Kumar Jain; Vinod Kumar Dixit; Anil Kumar Gulati; Gopal Nath
BACKGROUND: Efficacy of Helicobacter pylori stool antigen enzyme immunoassay (HpSA) and stool PCR was evaluated, before and after treatment, in a country with a high prevalence of H. pylori infection. METHODOLOGY: A total of 52 patients with dyspeptic symptoms were included in the study. Antral biopsy was collected during pre- and post-therapy periods for rapid urease test (RUT) and PCR. Similarly stool specimens for PCR and HpSA test were collected during both the periods from all 52 patients. Biopsy, PCR and RUT results together were considered the "gold standard." RESULTS: On the basis of gold standard tests, 40/52 patients were H. pylori positive. The sensitivity and specificity of HpSA test were 80% and 83.3% respectively in untreated patients. On the other hand, the sensitivity and specificity of stool PCR in untreated patients were 72.5% and 100% respectively. After eradication therapy, the results of both RUT and biopsy PCR were negative in 87.5% and positive in 12.5% of the patients. Although post treatment sensitivity of HpSA and stool PCR was equal (60%), specificity of HpSA and stool PCR were 68.6% and 97.1% respectively. CONCLUSION: The H. pylori stool tests represent a non-invasive concept for diagnosis of infection. Both HpSA and stool PCR seem to be satisfactory tests for pre-eradication as well as assessment of infection. But stool PCR is a better indicator than HpSA test in the post-eradication assessment of infection.
Detection of Helicobacter pylori using nested polymerase chain reaction in gastric biopsy samples
(2008) Divya Mahajan; Anju Jain; Varsha Singh; A.K. Jain; G.R.K. Rao; Gopal Nath
Helicobacter pylori remains a controversial organism with regards to humans, its epidemiology still unclear nearly two decades after discovery. The present study was undertaken to estimate the prevalence of the organism in the gastrointestinal tract in symptomatic and asymptomatic subjects to understand its precise natural history in India. A total of 154 specimens were a part of the study. These included gastric biopsies from peptic ulcer disease and Non ulcer dyspepsia subjects, as visualized on endoscopy, saliva and stool samples from apparently normal healthy adults. Nested polymerase chain reaction was performed using the primers Hp1, Hp2, Hp3 targeting 16S rRNA gene. A prevalence of 65.1%, 100%, 66.7%, and 73.3% respectively was observed by polymerase chain reaction. No association was observed between the H.pylori status and the disease condition of the patient.
Diagnostic accuracy of direct drug susceptibility testing of second-line antitubercular drugs
(American Society for Microbiology, 2025) Kartiki Srivastava; Varsha Singh; Vinod Kumar Raikwar; Shampa Anupurba
It is well-established that direct drug susceptibility testing (DST) of Mycobacterium tuberculosis using a liquid medium for first-line drugs provides accurate and time-saving results. The purpose of this study was to determine whether DST for second-line drugs could be successfully performed using processed smear-positive specimens (direct DST) and whether this method is accurate and may result in a significant reduction in time. The accuracy and shorter turnaround time of this approach were established by comparing the results acquired through direct DST with those obtained through indirect DST. Of the 150 acid-fast bacteria smear-positive sputum specimens that were set up for direct DST, 130 (86.67%) produced results that could be reported. Direct DST reporting took an average of 10 days (range: 9–11 days). The time savings from direct DST to indirect DST, which took into account the time needed to isolate a culture and conduct DST, was 7 days on average (range: 6–9 days). When the direct and indirect DST results were compared, the concordance with levofloxacin (LFX), moxifloxacin (MOX), linezolid (LNZ), and clofazimine (CFZ) were 96.33%, 96.16%, 100%, and 99.24%, respectively. The sensitivity and specificity of the test result were 93.75%, 83.33%, 100%, and 100%, and 98.0, 99.10, 100, and 99.19% with an accuracy of 98%, 98%, 100%, and 99% for LFX, MOX, LNZ, and CFZ, respectively. Direct DST is a fast and accurate diagnostic technique for detecting second-line drug resistance in tuberculosis. © © 2025 Srivastava et al.
Drug resistance pattern and clonality in H. pylori strains
(Journal of Infection in Developing Countries, 2009) Varsha Singh; Shrutkirti Mishra; Pushpa Maurya; G.R. Koteswar Rao; Ashok Kumar Jain; Vinod Kumar Dixit; Anil Kumar Gulati; Gopal Nath
Background: This aim of this work was to determine the in vitro activity of clarithromycin, amoxycillin, metronidazole and tetracycline against Helicobacter pylori and clonality among resistant and sensitive strains isolated from North India. Methodology: A total of 68 H. pylori isolates from peptic ulcer disease and non ulcer dyspepsia patients were examined. These strains were subjected for determination of minimum inhibitory concentration of clarithromycin, amoxycillin, metronidazole and tetracycline. For molecular characterization of resistant and sensitive strains, enterobacterial repetitive intergenic consensus sequences (ERIC) and random amplified polymorphic DNA-PCR (RAPD-PCR) methods were used. Results: All the tested isolates were found resistant to metronidazole, while 65% were resistant to amoxycillin and 4.7% were resistant to clarithromycin. However, none of the isolates were found to be resistant to tetracycline. Molecular fingerprinting and cluster analysis of resistant and sensitive strains did not give clues for clonal spread of resistant strains. Conclusions: Various chromosomal mutations were seen in the putative resistance genes of resistant strains, possibly indicating selection pressure as the major cause of high resistance. Copyright © 2008 Singh et al.
Evaluation of nested PCR in detection of Helicobacter pylori targeting a highly conserved gene: HSP60
(2008) Varsha Singh; Shrutkirti Mishra; G.R.K. Rao; Ashok Kumar Jain; V.K. Dixit; Anil Kumar Gulati; Divya Mahajan; Michael McClelland; Gopal Nath
Objective: To comparatively evaluate a new nested set of primers designed for the detection of Helicobacter pylori targeting a highly conserved heat shock protein gene (Hsp60). Methods: A total of 60 subjects having peptic ulcer diseases were tested for the detection of H. pylori using rapid urease test (RUT), histology, culture, and polymerase chain reaction (PCR) in their antral biopsy specimens. A newly designed Hsp60 gene-based primer set was evaluated against commonly used PCR primers for detection of H. pylori. Results: Forty-six of the 60 study subjects were found positive for culture isolation and all the 46 culture-positive specimens were also positive with Hsp60 gene PCR. Of the 46 culture-positive specimens, 44 were positive for 16S rRNA gene, ureC gene, RUT, and histology whereas only 29 were positive with ureA gene PCR. Of the 14 culture-negative subjects, 10 were positive with 16S rRNA gene, 4 were positive with ureC (glmM) gene PCR, and 2 were positive with RUT and 1 was positive on histology. Conclusion: This study shows that nested amplification targeting Hsp60 gene is the most sensitive and specific with LR+ and LR - values of ∝ and 0, respectively, when compared with the other three PCR methods. Also, HSP60 gene-specific nested protocol was the most appropriate for detection of H. pylori in clinical specimens. This is particularly valuable because it can be used as a noninvasive method for detecting H. pylori infection in young children and also, in follow-up studies with peptic ulcer patients, on samples like feces and saliva. © 2008 The Authors.
HIV/AIDS stigma, perceived social support and mental health problems among HIV/AIDS children: a mediation analysis
(Taylor and Francis Ltd., 2023) Varsha Singh; Anupriya; Shikha Verma; Swaran Lata
Extensive research on HIV/AIDS stigma is conducted on adults, but it cannot be equated with the experiences of children. This makes it obvious to develop an inclusive research on child experience of HIV/AIDS stigma. For that reason, the present study investigates the relationship among HIV/AIDS stigma, perceived social support and mental health problems in HIV/AIDS children. A sample of 90 HIV/AIDS children aged 10–18 years from Moti Lal Nehru Hospital, Allahabad, Uttar Pradesh, India, were recruited. Participants were assessed on HIV/AIDS stigma, perceived social support and mental health problems. Descriptive statistics, correlational and regression analysis and mediation analysis were performed to accomplish the purpose of the study. Correlational analysis makes it evident that perceived social support is prominently negatively correlated with HIV/AIDS stigma (r (88) = −.670, p < 0.01) whereas mental health problems (r (88) = .753, p < 0.01) was significantly positively correlated with HIV/AIDS stigma. Taking hierarchical regression analysis into consideration, it was found that the perceived social support significantly contributed to 33.2% variance in HIV/AIDS stigma and HIV/AIDS stigma contributed to 45.9% variance in mental health problems. Results of the mediation analyses validate the mediating role of HIV/AIDS stigma in the association between perceived social support and mental health problems (β = −0.27, CI = −.33 to −.034, p = .017). These findings contribute to empirical evidence about psychological predictors and the observable consequences of HIV/AIDS-related stigma. © 2022 Informa UK Limited, trading as Taylor & Francis Group.
Identification of high yielding and yellow mosaic virus resistance blackgram (Vigna mungo L. Wilczek) genotypes using multivariate analysis
(Springer, 2024) Varsha Singh; Mahendra Narain Singh; Anil Kumar Singh; Kartik Madankar; B. Sinha
21 blackgram genotypes, including the infector ‘Co 5’, were raised in a Completely Randomized Block design with two replications for two consecutive years (2018 and 2019) to screen blackgram yellow mosaic virus (MYMV) disease resistance under field conditions. Two genotypes viz., NDU 1 and Co 5 were highly susceptible to MYMV having PDI > 40% while other genotypes were resistant with PDI up to 10%. In general, genotypes with higher PDI (> 40%) had a lower number of pods per plant (NPP) and vice versa. The average number of susceptible genotypes pods per plant showed 23.75% reduction in number of pods per plant compared with resistant genotypes. These genotypes have undergone multivariate analysis including genetic variability, correlation, divergence and principal component analysis for eleven biometric traits. Principal component analysis revealed significant variation among traits with the first three principal components explaining approximately 74% of the total variation. Seed yield per plant; days to 50% flowering and percent disease index are important traits determining most of the variation. Mash 338, R3/12, R3/28 and PU 31 are the promising blackgram genotypes identified in the present study. These genotypes will be used to develop high yielding MYMV resistant blackgram varieties having other desirable yield traits. © The Author(s) under exclusive licence to Society for Plant Research 2023.
Iron phthalocyanine integrated with boron-doped reduced graphene oxide for highly selective four-electron oxygen reduction: an experimental study
(Royal Society of Chemistry, 2024) Vikram Rathour; Smita Singh; Varsha Singh; Devesh Kumar Singh; Mamta Yadav; Ananya Tiwari; Vellaichamy Ganesan
Iron phthalocyanine (FePc) has been integrated on boron-doped reduced graphene oxide (B-RGO) resulting in the composite, FePc@B-RGO. Boron alters the electronic structure around FePc and shows a higher selectivity than that of the benchmark catalyst, Pt/C, for four-electron oxygen reduction. FePc@B-RGO exhibits high oxygen reduction reaction activity with a high onset potential and half-wave potential (0.95 and 0.85 V vs. RHE respectively). FePc@B-RGO also shows a low Tafel slope of 39 mV dec−1 and high efficiency, stability, and methanol crossover for oxygen reduction in basic media. © 2024 RSC
Molecular and functional characterization of catfish (Heteropneustes fossilis) aquaporin-1b: Changes in expression during ovarian development and hormone-induced follicular maturation
(Academic Press Inc., 2011) Radha Chaube; François Chauvigné; Angèle Tingaud-Sequeira; Keerikkattil P. Joy; Arup Acharjee; Varsha Singh; Joan Cerdà
The oocytes of the freshwater catfish Heteropneustes fossilis hydrate during hormone-induced meiotic maturation. To investigate if this process may be mediated by aquaporins (AQPs), as it occurs in marine fish producing highly hydrated eggs, the cloning of ovarian AQPs in catfish was carried out. Using degenerate primers for conserved domains of the major intrinsic protein (MIP) family, and 5′ and 3′end amplification procedures, a full-length cDNA encoding for an AQP1-like protein was isolated. The predicted protein showed the typical six transmembrane domains and two Asn-Pro-Ala (NPA) motifs conserved among the members of the AQP superfamily. Phylogenetic analysis indicated that the catfish AQP clustered with the teleost-specific aquaporin-1b subfamily, and accordingly it was termed HfAqp1b. Heterologous expression in Xenopus laevis oocytes indicated that HfAqp1b encoded for a functional AQP, water permeability being enhanced by cAMP. Site-directed mutagenesis revealed that cAMP induced the translocation of HfAqp1b into the oocyte plasma membrane most likely through the phosphorylation of HfAqp1b Ser227. In adult catfish, hfaqp1b transcripts were detected exclusively in ovary and brain and showed significant seasonal variations; in the ovary, hfaqp1b was maximally expressed during the pre-spawning period, whereas in the brain the highest expression was detected during spawning. In vitro stimulation of isolated catfish ovarian follicles with vasotocin (VT) or human chorionic gonadotropin (hCG), which induce oocyte maturation and hydration, elevated the hfaqp1b transcript levels after 6 or 16h of incubation, respectively. These results suggest that HfAqp1b may play a role during VT- and hCG-induced oocyte hydration in catfish, and that VT may regulate HfAqp1b at the transcriptional and post-translational level in a manner similar to the vasopressin-dependent mammalian AQP2. © 2010 Elsevier Inc.
NaCl-templated synthesis of soybean-derived nitrogen-rich mesoporous carbon material: iron phthalocyanine integration for four-electron oxygen reduction
(Royal Society of Chemistry, 2024) Vikram Rathour; Smita Singh; Varsha Singh; Devesh Kumar Singh; Vaibhav Verma; Piyush Kumar Sonkar; Vellaichamy Ganesan
The performance efficiency of fuel cells and metal-air batteries mainly depends on the cathodic oxygen reduction reaction (ORR). In this work, soybean-derived mesoporous carbon is synthesized by the carbonization of soybean powder using an inexpensive template, NaCl which creates porosity as well as limits the vaporization of heteroatoms by generating a protective layer. Soybean powder carbonized at 950 °C (SN950) shows high catalytic activity towards ORR in basic medium. To further enhance the ORR activity, iron phthalocyanine (FePc) was immobilized on the soybean-derived carbon and the resulting material is represented as FePc@SN950. FePc@SN950 and other control samples were characterized by Fourier-transform infrared spectroscopy, X-ray diffraction, Raman spectroscopy, scanning electron microscopy, high-resolution transmission electron microscopy, Brunauer-Emmett-Teller analysis, and X-ray photoelectron spectroscopy techniques. FePc@SN950 shows an onset potential (Eonset) of 0.97 and 0.77 V (vs. RHE) and half-wave potential (E1/2) of 0.92 and 0.70 V (vs. RHE) in basic and acidic media, respectively. Selectivity and percentage formation of H2O2 of the materials are measured by hydrodynamic experiments. The number of electrons transferred is found to be 3.5 and 3.8 in basic and acidic media, respectively. The selectivity for the formation of water was evaluated as 80% and 94% respectively in the basic and acidic media throughout the ORR region. The stability and durability of the material are checked by amperometry and cyclic voltammetry (CV) methods, where there are no significant changes in the current and Eonset values after 10 000 s and 3000 CV cycles respectively, in both acidic and basic media. Therefore, it is demonstrated that the synthesized SN950 has a large potential to replace conventional catalytic supports (like graphene, carbon nanotubes, and carbon fiber). FePc@SN950 could be used as a potential candidate to replace Pt-based catalysts in fuel cells and metal-air batteries. © 2024 The Royal Society of Chemistry.
Pharmacological Insights: Mitochondrial ROS Generation by FNC (Azvudine) in Dalton’s Lymphoma Cells Revealed by Super Resolution Imaging
(Springer, 2024) Naveen Kumar; Vikram Delu; Ilya Ulasov; Sanjay Kumar; Rishi Kant Singh; Sandeep Kumar; Alok Shukla; Anand Kumar Patel; Lokesh Yadav; Ruchi Tiwari; Kumari Rachana; Shivashish Priyadarshi Mohanta; Varsha Singh; Anuradha Yadav; Kaushalendra Kaushalendra; Arbind Acharya
Nucleoside analogs are a common form of chemotherapy that disrupts DNA replication and repair, leading to cell cycle arrest and apoptosis. Reactive oxygen species (ROS) production is a significant mechanism through which these drugs exert their anticancer effects. This study investigated a new nucleoside analog called FNC or Azvudine, and its impact on ROS production and cell viability in Dalton’s lymphoma (DL) cells. The study found that FNC treatment resulted in a time- and dose-dependent increase in ROS levels in DL cells. After 15 and 30 min of treatment with 2 and 1 mg/ml of FNC, mitochondrial ROS production was observed in DL cells. Furthermore, prolonged exposure to FNC caused structural alterations and DNA damage in DL cells. The results suggest that FNC’s ability to impair DL cell viability may be due to its induction of ROS production and indicate a need for further investigation. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2024.
Phenosafranine integrated sulfonic acid-functionalized multi-walled carbon nanotubes for Cr(VI) detection
(Elsevier Ltd, 2024) Ananya Tiwari; Mamta Yadav; Smita Singh; Varsha Singh; Vikram Rathour; Vellaichamy Ganesan
This work presents the electroanalytical detection of hexavalent chromium, Cr(VI) using glassy carbon electrode modified with phenosafranine (PS+) ion exchanged on sulfonic acid-functionalized multi-walled carbon nanotubes (MWCNT-SO3H) i.e., MWCNT-SO3--PS+ as an electrochemical sensing platform (ESP). The prepared material, MWCNT-SO3--PS+ is assessed using various physiochemical characterization techniques for the successful ion exchange of PS+ onto the MWCNT-SO3H. The electrochemical viability of PS + for the electrocatalysis at the prepared ESP is tested using cyclic voltammetry. The ESP shows high sensitivity and selectivity towards Cr(VI) determination in the presence of several possible interferences with a limit of detection of 0.36 μM. Water samples from two sources are utilized for the real sample analyses showing a high recovery percentage with acceptable average relative standard deviation values. The proposed ESP exhibits high operational stability and storage stability with negligible change in current for more than a month. © 2024 Elsevier B.V.
Prevalence of Helicobacter pylori in asymptomatic subjects-A nested PCR based study
(2008) Shrutkirti Mishra; Varsha Singh; G.R.K. Rao; V.K. Dixit; A.K. Gulati; Gopal Nath
The aim of the study was to see the prevalence of Helicobacter pylori in asymptomatic children and adults by using nested PCR which is considered to be more specific than serological methods. Saliva and stool samples of 137 healthy children (aged 8 months to 16 y) and 108 asymptomatic adults (aged 17-60 y) were collected. PCR with primers targeting Hsp60 gene sequence of H. pylori was used. H. pylori positivity with nested PCR was observed in 45.7% (112/245) of the saliva and 42.8% (105/245) of the stool specimens. Prevalence of H. pylori in saliva was found to be 2.1%, 22.7%, 55.9%, 56.0%, 68.9% and 62.9% in the age groups of <5 y, 6-10 y, 11-16 y, 17-30 y, 31-45 y and 45-60 y, respectively. The detection rates in stool were 4.25% in <5 y, 13.64% in 6-10 y, 50% in 11-16 y, 64% in 17-30 y, 58.62% in 31-45 y and 61.1% in 45-60 y of age groups. The most favourable age group for acquiring the infection was 11-16 y. H. pylori positivity increased with lowering of socioeconomic status. There was no gender bias in prevalence of the bacterium. © 2008 Elsevier B.V. All rights reserved.
Recent Advancement in Organic Aerosol Understanding: a Review of Their Sources, Formation, and Health Impacts
(Institute for Ionics, 2023) Sadashiv Chaturvedi; Amit Kumar; Varsha Singh; Biswameet Chakraborty; Rupesh Kumar; Liu Min
Understanding the sources, mechanisms, and potential health impacts of volatile organic compounds (VOC) and secondary organic aerosols (SOA) is crucial for safeguarding human health, promoting sustainable industry and infrastructure practices, and addressing climatic challenges. These compounds originating from both anthropogenic and natural activities play a pivotal role in shaping air quality, climate dynamics, and public well-being. A comprehensive comprehension of their processes, interactions, and influence on atmospheric chemistry is imperative for devising effective strategies to mitigate associated health risks. This review comprehensively addresses the formation of biogenic and anthropogenic SOA, elucidates the intricate chemistry governing SOA generation, and expounds upon their far-reaching impacts. By encompassing diverse aspects such as tropospheric ozone, indoor and outdoor VOC and SOA formation, and the dynamic processes occurring during day and night cycles, this study facilitates a holistic understanding of the intricate interplay between VOC, SOA, and environmental dynamics, additionally underscores the importance of polycyclic aromatic hydrocarbons (PAHs) in this context. A deeper grasp of VOC and SOA sources, their transformation mechanisms, and the resulting implications will foster innovative solutions aimed at minimizing health risks, advancing sustainable industry practices, and driving climate action. This review delves into the multifaceted realm of VOC and SOA, highlighting their significance in achieving sustainable development goals (SDGs), particularly SGD-3 (Good Health and Well-being), 9 (Industry, Innovation, and Infrastructure), and 13 (Climate Action). © 2023, The Author(s), under exclusive licence to Springer Nature Switzerland AG.
Synthesized Gold Nanoparticles with Moringa Oleifera leaf Extract Induce Mitotic Arrest (G2/M phase) and Apoptosis in Dalton’s Lymphoma Cells
(Springer, 2024) Sandeep Kumar; Alok Shukla; Surya Pratap Singh; Rishi Kant Singh; Anand Kumar Patel; Praveen Kumar Verma; Sanjay Kumar; Naveen Kumar; Varsha Singh; Kirti Wasnik; Arbind Acharya
The therapeutic potential of chemically synthesized AuNPs has been demonstrated in various types of cancer. However, gold nanoparticles (AuNPs) synthesized using typical chemical methods have concerns regarding their environmental safety and adverse impact on human well-being. To overcome this issue, we used an environmentally friendly approach in which gold nanoparticles were synthesized using Moringa oleifera leaf extract (MLE). The present research was mainly focused on the biosynthesis and characterization of gold nanoparticles (AuNPs) using Moringa oleifera leaf extract (MLE-AuNPs) and explore its anticancer potential against Dalton’s Lymphoma (DL) cells. Characterization of the MLE-AuNPs was conducted using UV-Vis Spectroscopy to confirm the reduction process, FTIR analysis to ascertain the presence of functional groups, and XRD analysis to confirm the crystallinity. SEM and TEM images were used to examine size and morphology. After characterization, MLE-AuNPs were evaluated for their cytotoxic effects on Dalton’s lymphoma cells, and the results showed an IC50 value of 75 ± 2.31 µg/mL; however, there was no discernible cytotoxicity towards normal murine thymocytes. Furthermore, flow cytometric analysis revealed G2/M phase cell cycle arrest mediated by the downregulation of cyclin B1 and Cdc2 and upregulation of p21. Additionally, apoptosis induction was evidenced by Annexin V Staining, accompanied by modulation of apoptosis-related genes including decreased Bcl-2 expression and increased expression of Bax, Cyt-c, and Caspase-3 at both the mRNA and protein levels. Collectively, our findings underscore the promising anti-cancer properties of MLE-AuNPs, advocating their potential as a novel therapeutic avenue for Dalton’s lymphoma. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2024.
Unveiling Enhanced Oxygen Reduction in Multi-Walled Carbon Nanotube-Supported MnCo2O4: Experimental and Theoretical Insights into Tin Substitution for Octahedral Cobalt
(American Chemical Society, 2024) Smita Singh; Anshu Shrivastava; Varsha Singh; Vikram Rathour; Indrajit Sinha; Vellaichamy Ganesan
In this work, Sn-doped manganese cobaltite (Snx-MnCo2O4) was synthesized by using a solvothermal method followed by an annealing process. To further increase its catalytic efficiency, it was integrated onto a carbon support, carboxylic acid-functionalized multiwalled carbon nanotubes (fMWCNTs). Among the synthesized materials, fMWCNT-supported Sn-doped MnCo2O4 exhibits the highest onset potential for oxygen reduction and shows a distinctly selective four-electron oxygen reduction, as demonstrated by the rotating disc electrode and rotating ring disc electrode experiments. X-ray photoelectron spectroscopy reveals a shift in the binding energy of Mn 2p owing to alterations in the electronic structure of the crystal upon incorporation of Sn into MnCo2O4. Computational studies proved the replacement of octahedral Co ions in the MnCo2O4 crystal structure by Sn4+ ions. The withdrawal of electron density by Sn4+ species from the active centers (Mn3+) leads to an increased electropositive character at the Mn3+ centers. Since Mn3+ centers are the effective active centers in this catalyst, oxygen is efficiently adsorbed at these active centers, resulting in enhanced electrocatalytic activity. © 2024 American Chemical Society.
Vasotocin stimulates maturation-inducing hormone, oocyte maturation and ovulation in the catfish Heteropneustes fossilis: Evidence for a preferential calcium involvement
(Elsevier Inc., 2021) Varsha Singh; Radha Chaube; K.P. Joy
Arginine vasotocin (VT) is the basic neurohypophysial nonapeptide hormone in teleosts. VT is also distributed in the ovary of the catfish Heteropneustes fossilis and induces final oocyte maturation (FOM) and ovulation by stimulating the maturation-inducing hormone (MIH). The present study reports the effects of cAMP (0.5 mM), phosphodiesterase inhibitors (IBMX -0.5 mM and theophylline- 0.5 mM), the inositol triphosphate (IP3) receptor inhibitor heparin (10 μg/mL) and the Ca2+ chelator BAPTA-AM (25 μM) on VT (100 nM) - induced progestin stimulation, FOM and ovulation. Incubation of post-vitellogenic follicles with cAMP, IBMX and theophylline for 0, 8, 16 and 24 h stimulated basal secretion of progesterone (P4), 17-hydroxyprogesterone (17-P) and 17, 20β-dihydroxy-4-pregnen-3-one (MIH) in a duration-dependent manner. The incubation of the follicles with heparin stimulated P4 modestly, and 17-P and MIH levels in a duration-dependent manner. The incubation of the follicles with BAPTA-AM stimulated P4 and MIH levels marginally and 17-P robustly. The stimulation was in the order cAMP > IBMX > theophylline > heparin > BAPTA-AM. The incubation of the follicles with VT stimulated P4, 17-P, MIH, GVBD and ovulation in a duration-dependent manner. The co-incubations with VT and the test compounds inhibited the VT-induced stimulation of P4, 17-P and MIH levels in a time-dependent manner in the order heparin > BAPTA-AM > cAMP > IBMX > theophylline. Concurrently, the VT-induced stimulation of GVBD and ovulation were also inhibited by the test compounds in the same order. The results show that VT induces FOM and ovulation preferentially acting through Ca2+ pathway and a crosstalk between Ca2+ and cAMP signaling pathways seems to integrate the processes. © 2021 Elsevier Inc.