Browsing by Author "Abhishek Kumar Singh"

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A Lithography-Free Fabrication of Low-Operating Voltage-Driven, Very Large Channel Length Graphene Field-Effect Transistor with NH3Sensing Application
(Institute of Electrical and Electronics Engineers Inc., 2020) Nitesh K. Chourasia; Abhishek Kumar Singh; Suyash Rai; Anand Sharma; P. Chakrabarti; Anchal Srivastava; Bhola N. Pal
Large-area-based field-effect transistor (FET) gas sensor has the potential to provide a larger sensing area for a chemical analyte. So far, graphene FETs (GFETs) are mostly fabricated by expensive lithographic techniques with a minimum channel length. We have demonstrated a simple way to fabricate a very large channel length of 0.45 mm GFET using ion-conducting dielectric with thermally evaporate source/drain electrodes and has been demonstrated for an application of ambient atmosphere ammonia gas sensing. Ion-conducting Li5AlO4 gate dielectric has reduced operating voltage up to 2.0 V with good current saturation. The chemical vapor deposition (CVD) grown uniform monolayer of graphene has been used as an active channel layer of FET. The fabricated device has been tested for different concentrations of ammonia in ambient environment conditions at 25 °C temperature, which indicates that the Dirac point voltage of the device varies up to 0.8 V when the concentration of ammonia has been changed from 0 to 3 ppm. Moreover, this study also reveals that this GFET is capable of detecting ammonia up to the concentration level of 0.1 ppm. © 1963-2012 IEEE.
Antigens activated SOCS3+CD200R+CD4+ T cells are critical to Leishmania pathogenesis and a distinctive target for vaccine development
(Elsevier Ltd, 2025) Abhishek Kumar Singh; Baishakhi Mahapatra; Ankita Srivastava; Samer Singh; Pradeep Kumar Das; Rakesh Kumar Singh
The expression of suppression of cytokine signalling protein (SOCS3) has been posited as a critical determinant of T cells differentiation and maturation during visceral leishmaniasis (VL), however, the antigen-activated CD4+ T cell phenotypes expressing this protein have not been explored much. Since, the inherent nature of SOCS3 protein directs the polarization of CD4+ T cells towards anti-inflammatory Th2 axis, the identification of SOCS3 expressing T-cell phenotypes will provide a better understanding on Leishmania immunobiology. Our previous findings have delineated a distinct Leishmania antigens activated CD4+ T cells phenotype expressing CD200R receptor that acts as prime anti-inflammatory disease promoting subset. Here, in this study we observed that the SOCS3+ antigen activated CD200R+CD4+ T cells phenotype is succinctly involved in cytokines regulation during Leishmania infection. We further observed that CD200R+CD4+ T cells expressing higher levels of SOCS3 protein have the potential to polarize these cells to produce more IL-10, and less IL-12 & IFN-γ as compared to CD200R−CD4+T cells on exposure to whole killed Leishmania vaccine in a mice model of VL. Furthermore, the observed decline in splenic SOCS3 expression along with inflammatory factors like prostaglandin E2, upon abrogation of CD200R signalling in Leishmania infected animals suggest a coordinated role of CD200R and SOCS3 protein in VL pathogenesis. These findings prompted us to study the potential of CD200R and SOCS3 in the vaccine-induced immunity. Immunization with an in-house whole killed Leishmania vaccine adjuvanted with anti-CD200 antibodies not only reduced splenic SOCS3 expression but also enhanced CD4+ T cells' effector functions and their memory conversion. The down-regulation of splenic SOCS3 was also found correlated with reduced granuloma and parasitic load in SOCS3-low mice groups. Hence, the identified SOCS3+CD200R+CD4+ T cells subset reveals a potential disease-promoting phenotype that can be targeted to enhance the immunogenicity of Leishmania antigens. © 2025
Assessing L. donovani Skin Parasite Load: A Proof of Concept Study of a Microbiopsy Device in an Indian Setting
(Frontiers Media S.A., 2021) Kristien Cloots; Om Prakash Singh; Abhishek Kumar Singh; Gert Van der Auwera; Prashant Kumar; Mallikarjuna Rao Gedda; Tulika Kumari Rai; Epco Hasker; Shyam Sundar; Marleen Boelaert
Background: In the endgame of the elimination initiative of visceral leishmaniasis (VL) on the Indian subcontinent, one of the main questions remaining is whether asymptomatically infected individuals also contribute to transmission. We piloted a minimally invasive microbiopsy device that could help answer this question. While the potential of this device has been previously illustrated in Ethiopia, no such information is available for the setting of the Indian subcontinent. In this proof of concept study we aimed to assess 1) to what extent skin parasite load obtained with the new microbiopsy device correlates with disease status, 2) to what extent skin parasite load correlates with blood parasite load in the same subject, and 3) to what extent the skin parasite load obtained from different sampling sites on the body correlates with one another. Methods: We performed a pilot study in Bihar, India, including 29 VL patients, 28 PKDL patients, 94 asymptomatically infected individuals, 22 endemic controls (EC), and 28 non-endemic controls (NEC). Presence of infection with L. donovani in the blood was assessed using Direct Agglutination Test, rK39 ELISA, Whole Blood Analysis measuring IFN-γ and qPCR. A skin sample was collected with the microbiopsy device on two different locations on the body. PKDL patients provided a third skin sample from the edge of a PKDL lesion. Parasite load in the skin was measured by qPCR. Findings: We found a clear correlation between the skin parasite load obtained with the microbiopsy device and disease status, with both higher skin parasite loads and higher proportions of positive skin samples in VL and PKDL patients compared to asymptomatics, EC, and NEC. No clear correlation between skin parasite load and blood parasite load was found, but a moderate correlation was present between the skin parasite load in arm and neck samples. In addition, we found four positive skin samples among asymptomatic individuals, and 85% of PKDL lesions tested positive using this microbiopsy device. Conclusions: In line with previous pilot studies, our results from an Indian setting suggest that the microbiopsy device provides a promising tool to measure skin parasite load, and – if validated by xenodiagnosis studies – could facilitate much needed larger scale studies on infectiousness of human subgroups. In addition, we advocate further evaluation of this device as a diagnostic tool for PKDL. © Copyright © 2021 Cloots, Singh, Singh, Van der Auwera, Kumar, Gedda, Rai, Hasker, Sundar and Boelaert.
Assessment of feeding hydroponic fodder on growth and reproduction performance in Black Bengal goat
(Springer Science and Business Media B.V., 2024) Shailendra Kumar Rajak; Arvind Kumar Singh; Abhishek Kumar Singh; Asish Rai; Anshu Gangwar
This study aimed to evaluate the effects of hydroponic fodder on the growth and reproductive performance of Black Bengal goats in East Champaran, Bihar, during the years 2020-21 and 2021-22. A total of 24 goats were randomly assigned to four groups: Control (C) with extensive grazing, gram straw, concentrate feed, and green fodder; Treatment 1 (T1) receiving C + 300 g/day of wheat hydroponic fodder; Treatment 2 (T2) with 300 g/day of maize hydroponic fodder alone; and Treatment 3 (T3) receiving C + a combination of 150 g/day of wheat and 150 g/day of maize hydroponic fodder. Each group comprised 6 animals. The nutrient composition analysis revealed that wheat hydroponic fodder had significantly higher (P < 0.05) levels of dry matter, crude protein, and lignin, whereas maize contained higher nitrogen-free extract, crude fiber, ether extract, and ash. In terms of growth performance, T3 showed the highest body weight gain and daily weight gain, outperforming T2, T1, and the control group (P < 0.05). Though differences between T2 and T3 were not significant (P > 0.05) across both years, T3 consistently exhibited better performance. Reproductive performance indicators, such as age at puberty, age of first kidding, and kid mortality rates, were significantly lower (P < 0.05) in T3, T1, and the control group compared to T2. However, there were no significant differences (P > 0.05) between T2 and T3 in these parameters. T3 also showed the highest kidding size and birth weight of kids (P < 0.05), followed by T2, T1, and the control group. The cost of feed per kilogram of body weight gain was lowest in T3, followed by T2, T1, and the control. In conclusion, the combination of maize and wheat hydroponic fodder (T3) resulted in better growth and reproductive performance compared to feeding maize or wheat hydroponic fodder alone. Furthermore, this feeding strategy reduced the cost per kilogram of live weight gain, indicating its potential for enhancing the sustainability and profitability of goat farming systems in the region. © The Author(s), under exclusive licence to Springer Nature B.V. 2024.
CD8 T cell exhaustion in human visceral leishmaniasis
(2014) Shalini Gautam; Rajiv Kumar; Neetu Singh; Abhishek Kumar Singh; Madhukar Rai; David Sacks; Shyam Sundar; Susanne Nylén
Little is known about CD8 T cells in human visceral leishmaniasis (VL) and it is unclear if these cells have a protective, pathological and/or suppressive function. In experimental VL CD8 T cells have been shown to contribute to parasite control and play an important role in vaccine-generated immunity. To better understand the role of CD8 T cells in human VL, we examined molecules associated with anergy and cytotoxic T lymphocytes (CTL) in peripheral blood mononuclear cells (PBMC) and splenic aspirates (SA), and in CD8 cells derived from these tissues. Gene and surface marker expression suggest that splenic CD8 cell predominantly display an anergic phenotype, whereas CD8-PBMC have features of both anergic cells and CTLs. CD8 cells contribute to the baseline IFNγ levels in whole blood (WB) and SA cultures, but not to the Leishmania induced IFNγ release that is revealed using WB cultures. Blockade of CTLA-4 or PD1 had no effect on IFNγ production or parasite survival in SA cultures. Following cure, CD8 T cells contribute to the Leishmania induced IFNγ production observed in Leishmania stimulated cell cultures. We suggest CD8 T cells are driven to anergy/exhaustion in human VL, which affect their ability to contribute to protective immune responses. © The Author 2013.
Correction to: Optimization of microwave parameters to enhance phytochemicals, antioxidants and metabolite profile of de-oiled rice bran (Scientific Reports, (2024), 14, 1, (23959), 10.1038/s41598-024-74738-1)
(Nature Research, 2025) Alonkrita Chowdhury; Alla Yaswanth Naveen Kumar; Rajesh Rakesh Kumar; Vivek Kumar Maurya; M. Satyanarayana Mahesh; Abhishek Kumar Singh; Pavan Kumar Yadav; Mayukh Ghosh
Correction to: Scientific Reportshttps://doi.org/10.1038/s41598-024-74738-1, published online 14 October 2024 The original version of this Article contained errors in the values of the phytochemical and antioxidant analysis. Consequently, in the Results and discussion section, under the subheading ‘Phytochemical analysis’, “The TPC values varied across the different treatment groups, ranging from 947.95 ± 11.72 to 1304.77 ± 9.50 µg GAE/g of DM. The control group had a TPC of 1164.32 ± 15.63 µg GAE/g of DM. Most treatment groups showed an increase in phenolic content compared to the control group, with T-1 exhibiting the highest TPC at 1304.77 ± 9.50 µg GAE/g of DM, followed by T-2, T-7, T-5, T-4, T-3, T-6, and T-8 in decreasing order (Fig. 1a). In contrast, the T-9 group showed a significant decrease in phenolic content compared to the control. These results indicate that microwave parameters have a notable impact on the total phenolic content of the treated DORB samples, highlighting the importance of optimizing these parameters to enhance nutritive value. The treatment-specific influence on TPC aligns with the findings of Pokkanta et al.8 in rice bran. They reported that microwaving at 260 watts for 0.5 to 3 min and at 440 watts for 0.5 to 2.5 min resulted in a maximum increase in phenolic content, while a decrease occurred at 880 watts. This study corroborates those findings, as the highest TPC was observed with the 300 watts for 3 min treatment (T-1), while a significant reduction was seen in the 800 watts for 5 min treatment (T-9). The reduction in T-9 might be due to the degradation of phenolics caused by prolonged exposure to high temperatures. The effectiveness of the 300 watts for 3 min microwave treatment in enhancing phenolic content could be attributed to factors such as the release of bound phenolics through the breakdown of cell walls and minimal thermal damage to bioactive compounds during the process45. The TFC varied among the different treatment groups, ranging from 482.73 ± 9.96 to 916.82 ± 16.29 µg QE/g of DM, with the control group having a TFC of 900.91 ± 11.5 µg QE/g of DM. Most treatment groups showed a significant increase in flavonoid content compared to the control. The T-6 treatment group exhibited the highest TFC, followed by T-4, T-7, T-1, T-2, T-5, and T-3 (Fig. 1b). A significant decrease in flavonoid content was observed in the T-9 group, while the TFC of T-8 was comparable to the control. The decrease in T-9, which involved treatment at 800 watts for 5 min, is likely due to the degradation of flavonoids caused by prolonged exposure to high-intensity microwaves13,46. A similar wattage-time -dependent variation in TFC in microwaved rice bran was also reported by Pokkanta et al.8 The flavonol content ranged from 6.59 ± 0.77 to 43.35 ± 0.88 µg CE/g of DM among the treated samples, whereas the control group had a much lower flavonol content of 1.87 ± 0.22 µg CE/g of DM. All treated samples exhibited a significant (p < 0.05) increase in flavonol content compared to the control, indicating that microwave treatment positively influenced flavonol levels in DORB. The highest flavonol content was observed in the T-7 group (800 watts for 1.5 min), which yielded a concentration of 43.35 ± 0.88 µg CE/g of DM, followed by T-6, T-5, T-4, T-3, T-2, T-1, T-8, and T-9 (Fig. 1c).” now reads: “The TPC values varied across the different treatment groups, ranging from 1743.69 ± 3.2 to 3879.31 ± 24.67 µg GAE/g of DM. The control group had a TPC of 2082.75 ± 5.58 µg GAE/g of DM. Most treatment groups showed an increase in phenolic content compared to the control group, with T-1 exhibiting the highest TPC at 3879.31 ± 24.70 µg GAE/g of DM, followed by T-2, T-7, T-5, T-4, T-3, T-6, and T-8 in decreasing order (Fig. 1a). In contrast, the T-9 group showed a significant decrease in phenolic content compared to the control. These results indicate that microwave parameters have a notable impact on the total phenolic content of the treated DORB samples, highlighting the importance of optimizing these parameters to enhance nutritive value. The treatment-specific influence on TPC aligns with the findings of Pokkanta et al.8 in rice bran. They reported that microwaving at 260 watts for 0.5 to 3 min and at 440 watts for 0.5 to 2.5 min resulted in a maximum increase in phenolic content, while a decrease occurred at 880 watts. This study corroborates those findings, as the highest TPC was observed with the 300 watts for 3 min treatment (T-1), while a significant reduction was seen in the 800 watts for 5 min treatment (T-9). © The Author(s) 2025.
Corrigendum to “Antigens activated SOCS3+CD200R+CD4+ T cells are critical to Leishmania pathogenesis and a distinctive target for vaccine development” [Vaccine 62 (2025) 127501] (Vaccine (2025) 62, (S0264410X25007984), (10.1016/j.vaccine.2025.127501))
(Elsevier Ltd, 2025) Abhishek Kumar Singh; Baishakhi Mahapatra; Ankita Srivastava; Samer Singh; Pradeep Kumar Das; Rakesh Kumar Singh
The authors regret the error in the acknowledgements in the published article (DOI: https://doi.org/10.1016/j.vaccine.2025.127501). The original text: This work is an output of a project funded to RKS by the Indian Council of Medical Research, New Delhi (No. VIR/12/2022/ECD-1). AS and BM are thankful to UP-CST, Lucknow, and DBT, New Delhi, respectively for their research fellowships. RKS also acknowledges the support received under the Institute of Eminence (IoE 6031), Central Government of India, and Uttar Pradesh council of science and technology (UP-CST/D-2245) for financial assistance. The corrected version: This work is an output of a project funded to RKS by the Indian Council of Medical Research, New Delhi (No. VIR/12/2022/ECD-1). AS and BM are thankful to UP-CST, Lucknow, and DBT, New Delhi, respectively for their research fellowships. RKS also acknowledges the support received under the Institute of Eminence (IoE 6031), Central Government of India, and Uttar Pradesh council of science and technology (UP-CST/D-2245) for financial assistance. PD, the recipient of ICMR-Emeritus Scientist, acknowledges the support of ICMR, New Delhi. This amendment ensures proper acknowledgement of contributions. We sincerely apologize for any inconvenience caused and thank the editors for their understanding. © 2025 Elsevier Ltd
Determinants for progression from asymptomatic infection to symptomatic visceral leishmaniasis: A cohort study
(Public Library of Science, 2018) Jaya Chakravarty; Epco Hasker; Sangeeta Kansal; Om Prakash Singh; Paritosh Malaviya; Abhishek Kumar Singh; Ankita Chourasia; Toolika Singh; Medhavi Sudarshan; Akhil Pratap Singh; Bhawana Singh; Rudra Pratap Singh; Bart Ostyn; Michaela Fakiola; Albert Picado; Joris Menten; Jenefer M. Blackwell; Mary E. Wilson; David Sacks; Marleen Boelaert; Shyam Sundar
Background: Asymptomatic Leishmania donovani infections outnumber clinical presentations, however the predictors for development of active disease are not well known. We aimed to identify serological, immunological and genetic markers for progression from L. donovani infection to clinical Visceral Leishmaniasis (VL). Methods: We enrolled all residents >2 years of age in 27 VL endemic villages in Bihar (India). Blood samples collected on filter paper on two occasions 6–12 months apart, were tested for antibodies against L. donovani with rK39-ELISA and DAT. Sero converters, (negative for both tests in the first round but positive on either of the two during the second round) and controls (negative on both tests on both occasions) were followed for three years. At the start of follow-up venous blood was collected for the following tests: DAT, rK39- ELISA, Quantiferon assay, SNP/HLA genotyping and L.donovani specific quantitative PCR. Results: Among 1,606 subjects enrolled,17 (8/476 seroconverters and 9/1,130 controls) developed VL (OR 3.1; 95% CI 1.1–8.3). High DAT and rK39 ELISA antibody titers as well as positive qPCR were strongly and significantly associated with progression from seroconversion to VL with odds ratios of 19.1, 30.3 and 20.9 respectively. Most VL cases arose early (median 5 months) during follow-up. Conclusion: We confirmed the strong association between high DAT and/or rK39 titers and progression to disease among asymptomatic subjects and identified qPCR as an additional predictor. Low predictive values do not warrant prophylactic treatment but as most progressed to VL early during follow-up, careful oberservation of these subjects for at least 6 months is indicated. © 2018, Public Library of Science. All rights reserved. https://creativecommons.org/publicdomain/zero/1.0/.
Diagnosis of Visceral Leishmaniasis in an Elimination Setting: A Validation Study of the Diagnostic Algorithm in India
(Multidisciplinary Digital Publishing Institute (MDPI), 2022) Kristien Cloots; Om Prakash Singh; Abhishek Kumar Singh; Anurag Kumar Kushwaha; Paritosh Malaviya; Sangeeta Kansal; Epco Hasker; Shyam Sundar
Visceral leishmaniasis (VL) is on the verge of elimination on the Indian subcontinent. Nonetheless, the currently low VL-incidence setting brings along new challenges, one of which is the validity of the diagnostic algorithm, based on a combination of suggestive clinical symptoms in combination with a positive rK39 Rapid Diagnostic Test (RDT). With this study, we aimed to assess the positive predictive value of the diagnostic algorithm in the current low-endemic setting in India by re-assessing newly diagnosed VL patients with a qPCR analysis on venous blood as the reference test. In addition, we evaluated the specificity of the rK39 RDT by testing non-VL cases with the rK39 RDT. Participants were recruited in Bihar and Uttar Pradesh, India. VL patients diagnosed based on the diagnostic algorithm were recruited through six primary health care centers (PHCs); non-VL cases were identified through a door-to-door survey in currently endemic, previously endemic, and non-endemic clusters, and tested with rK39 RDT, as well as—if positive—with qPCR on peripheral blood. We found that 95% (70/74; 95% CI 87–99%) of incident VL cases diagnosed at the PHC level using the current diagnostic algorithm were confirmed by qPCR. Among 15,422 non-VL cases, 39 were rK39 RDT positive, reflecting a specificity of the test of 99.7% (95% CI 99.7–99.8%). The current diagnostic algorithm combining suggestive clinical features with a positive rK39 RDT still seems valid in the current low-endemic setting in India. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.
Exploring comparative nutritional dynamics of conventional and hybrid varieties of Moringa oleifera in goat rumen inoculum
(Range Management Society of India, 2025) Vasundhara Dhote; Sandeep Kumar Chaudhary; Mahipal Choubey; Abhishek Kumar Singh; Ajeet Singh; Ajit Kumar; Dharmesh Tewari
The present study aimed to evaluate the comparative nutritional value of Desi and PKM-1 varieties of Moringa oleifera foliage using in-vitro gas production (IVGP) technique in goat feeding. Five groups were established, with substrates comprising a mix of wheat straw and concentrate (60:40 ratio) without moringa foliage serving as the control (CON). The other groups were designated as P-10 and P-20 incorporating PKM-1 moringa foliage at 10% and 20%, respectively; and D-10 and D-20 incorporating Desi moringa foliage at 10% and 20%, respectively. The study revealed that PKM-1 variety exhibited significantly higher (P<0.01) organic matter (OM) and crude protein (CP) content, while total ash (TA) and neutral detergent fiber (NDF) content were significantly lower (P<0.05) compared to Desi moringa foliage. The polyphenolic content remained comparable (P>0.05) between both varieties. Additionally, PKM-1 showed significantly higher (P<0.05) levels of phosphorus (P), copper (Cu), iron (Fe), zinc (Zn) and manganese (Mn) minerals compared to Desi moringa foliage. Furthermore, total gas volume (ml/200 mg) produced after 24 hours of incubation was significantly (P<0.01) higher in P-20 group compared to CON, D-10, D-20, and P-10 groups. Substrate degradation, measured as truly degradable organic matter in the rumen (TDOMR in mg/200mg; %), was higher (P<0.01) in P-20 group, followed by D-20 and P-10 groups, while it was lowest in D-10 and CON groups. Microbial biomass production (MBP in mg/200 mg), efficiency of microbial biomass production (% TDOMR), and partitioning factor (PF in mg TDOMR/ml gas volume) were also higher (P<0.01) in P-20 group, followed by D-20, P-10, and D-10 groups, with the lowest values observed in CON group. Hence, the incorporation of PKM-1 Moringa oleifera foliage at 20% of total dry matter significantly enhanced substrate degradation, truly degradable organic matter in the rumen, and the efficiency of microbial biomass production in goat’s rumen inoculum, as compared to Desi variety. © Range Management Society of India.
Field-friendly anti-PGL-I serosurvey in children to monitor Mycobacterium leprae transmission in Bihar, India
(Frontiers Media SA, 2023) Louise Pierneef; Paritosh Malaviya; Anouk van Hooij; Shyam Sundar; Abhishek Kumar Singh; Rajiv Kumar; Danielle de Jong; Maaike Meuldijk; Awnish Kumar; Zijie Zhou; Kristien Cloots; Paul Corstjens; Epco Hasker; Annemieke Geluk
Background: It has been amply described that levels of IgM antibodies against Mycobacterium leprae (M. leprae) phenolic glycolipid I (PGL-I) correlate strongly with the bacterial load in an infected individual. These findings have generated the concept of using seropositivity for antibodies against M. leprae PGL-I as an indicator of the proportion of the population that has been infected. Although anti-PGL-I IgM levels provide information on whether an individual has ever been infected, their presence cannot discriminate between recent and past infections. Since infection in (young) children by definition indicates recent transmission, we piloted the feasibility of assessment of anti-PGL-I IgM seroprevalence among children in a leprosy endemic area in India as a proxy for recent M. leprae transmission. Material and methods: A serosurvey for anti-PGL-I IgM antibodies among children in highly leprosy endemic villages in Bihar, India, was performed, applying the quantitative anti-PGL-I UCP-LFA cassette combined with low-invasive, small-volume fingerstick blood (FSB). Results: Local staff obtained FSB of 1,857 children (age 3–11 years) living in 12 leprosy endemic villages in Bihar; of these, 215 children (11.58%) were seropositive for anti-PGL-I IgM. Conclusion: The anti-PGL-I seroprevalence level of 11.58% among children corresponds with the seroprevalence levels described in studies in other leprosy endemic areas over the past decades where no prophylactic interventions have taken place. The anti-PGL-I UCP-LFA was found to be a low-complexity tool that could be practically combined with serosurveys and was well-accepted by both healthcare staff and the population. On route to leprosy elimination, quantitative anti-PGL-I serology in young children holds promise as a strategy to monitor recent M. leprae transmission in an area. Copyright © 2023 Pierneef, Malaviya, van Hooij, Sundar, Singh, Kumar, de Jong, Meuldijk, Kumar, Zhou, Cloots, Corstjens, Hasker and Geluk.
Influence of Silicon Supplementation on Growth, Immunity, Antioxidant, Hormonal Profile and Bone Health Biomarkers in Pre-ruminant Crossbred Calves
(Springer, 2025) Lamella Ojha; Raman K. Malik; Veena Mani; Abhishek Kumar Singh; Manpreet Singh
Silicon (Si), a newer trace element, is believed to be important for healthy bone formation and to decrease bone resorption, improving the quality of bone by manipulating several hormones and enzymes. Therefore, the current investigation was conducted to determine the impact of Si supplementation on growth, immunity, antioxidant, hormonal profile and biomarkers of bone health in pre-ruminant crossbred calves. Twenty-four crossbred calves (5–7 days) were selected on the basis of their body weight (BW 31.65 ± 0.46 kg) and divided into 4 groups (n = 6) and fed as per ICAR (2013) feeding standards except that these were additionally supplemented with 0 (Si0), 50 (Si50), 100 (Si100) and 150 (Si150) mg of Si/kg dry matter (DM) in four respective groups for 90 days. Every month, peripheral blood samples were drawn (0, 30, 60 and 90 days post supplementing with Si) and analysed for antioxidant status, hormonal profile and bone health biomarkers. It is reported that dietary Si supplementation improved (P < 0.05) net body weight gain (kg), average daily gain (g) and average dry matter intake (kg), whereas feed intake (kg/100 kg BW), was not altered due to Si supplementation. Structural growth measurements were significantly higher (P < 0.05) in Si100 and Si150 groups as compared to Si50 and control groups. However, immune response (humoral as well as cell-mediated immunity), erythrocytic antioxidant enzymes (superoxide dismutase, SOD, glutathione peroxidase, GPx and catalase), plasma ferric reducing total antioxidant power (FRAP) activity and the plasma concentration of total immunoglobulins (TIg) remained unaffected by Si supplementation. Silicon increased (P < 0.05) the concentration of plasma growth hormone (GH), vitamin D3, bone alkaline phosphatase (BALP) and osteocalcin (OCN) in Si100 and Si150 groups, but the levels of calcitonin, parathyroid hormone (PTH) and hydroxyproline (HYP) remained similar among all the groups. As a result of the current investigation, it can be inferred that the inclusion of 100 and 150 mg of Si/kg DM was effective in improving the growth performance, growth hormone, vitamin D3 and bone health status in pre-ruminant calves. However, supplementation of 150 mg of Si/kg DM had no additional benefit; therefore 100 mg of Si/kg DM is the optimum level of Si supplementation in pre-ruminant calves. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2024.
Latent Infection with Leishmania donovani in Highly Endemic Villages in Bihar, India
(Public Library of Science, 2013) Epco Hasker; Sangeeta Kansal; Paritosh Malaviya; Kamlesh Gidwani; Albert Picado; Rudra Pratap Singh; Ankita Chourasia; Abhishek Kumar Singh; Ravi Shankar; Joris Menten; Mary Elizabeth Wilson; Marleen Boelaert; Shyam Sundar
Introduction: Asymptomatic persons infected with the parasites causing visceral leishmaniasis (VL) usually outnumber clinically apparent cases by a ratio of 4-10 to 1. We describe patterns of markers of Leishmania donovani infection and clinical VL in relation to age in Bihar, India. Methods: We selected eleven villages highly endemic for Leishmania donovani. During a 1-year interval we conducted two house to house surveys during which we collected blood samples on filter paper from all consenting individuals aged 2 years and above. Samples were tested for anti-leishmania serology by Direct Agglutination Test (DAT) and rK39 ELISA. Data collected during the surveys included information on episodes of clinical VL among study participants. Results: We enrolled 13,163 persons; 6.2% were reactive to DAT and 5.9% to rK39. Agreement between the tests was weak (kappa = 0.30). Among those who were negative on both tests at baseline, 3.6% had converted to sero-positive on either of the two tests one year later. Proportions of sero-positives and sero-converters increased steadily with age. Clinical VL occurred mainly among children and young adults (median age 19 years). Discussion: Although infection with L. donovani is assumed to be permanent, serological markers revert to negative. Most VL cases occur at younger ages, yet we observed a steady increase with age in the frequency of sero-positivity and sero-conversion. Our findings can be explained by a boosting effect upon repeated exposure to the parasite or by intermittent release of parasites in infected subjects from safe target cells. A certain proportion of sero-negative subjects could have been infected but below the threshold of antibody abundance for our serologic testing.
Livestock and rodents within an endemic focus of Visceral Leishmaniasis are not reservoir hosts for Leishmania donovani
(Public Library of Science, 2022) Anurag Kumar Kushwaha; Ashish Shukla; Breanna M. Scorza; Tulika Kumari Rai; Rahul Chaubey; Dharmendra Kumar Maurya; Shweta Srivastva; Shreya Upadhyay; Abhishek Kumar Singh; Paritosh Malviya; Om Prakash Singh; Vivek Kumar Scholar; Puja Tiwary; Shakti Kumar Singh; Phillip Lawyer; Edgar Rowton; Scott A. Bernhardt; Christine A. Petersen; Shyam Sundar
Leishmaniasis on the Indian subcontinent is thought to have an anthroponotic transmission cycle. There is no direct evidence that a mammalian host other than humans can be infected with Leishmania donovani and transmit infection to the sand fly vector. The aim of the present study was to evaluate the impact of sand fly feeding on other domestic species and provide clinical evidence regarding possible non-human reservoirs through experimental sand fly feeding on cows, water buffalo goats and rodents. We performed xenodiagnosis using colonized Phlebotomus argentipes sand flies to feed on animals residing in villages with active Leishmania transmission based on current human cases. Xenodiagnoses on mammals within the endemic area were performed and blood-fed flies were analyzed for the presence of Leishmania via qPCR 48hrs after feeding. Blood samples were also collected from these mammals for qPCR and serology. Although we found evidence of Leishmania infection within some domestic mammals, they were not infectious to vector sand flies. Monitoring infection in sand flies and non-human blood meal sources in endemic villages leads to scientific proof of exposure and parasitemia in resident mammals. Lack of infectiousness of these domestic mammals to vector sand flies indicates that they likely play no role, or a very limited role in Leishmania donovani transmission to people in Bihar. Therefore, a surveillance system in the peri-/post-elimination phase of visceral leishmaniasis (VL) must monitor absence of transmission. Continued surveillance of domestic mammals in outbreak villages is necessary to ensure that a non-human reservoir is not established, including domestic mammals not present in this study, specifically dogs. © 2022 Kushwaha et al.
Monitoring of Leishmania transmission in the postelimination phase: The potential of serological surveys
(Elsevier B.V., 2024) Kristien Cloots; Om Prakash Singh; Abhishek Kumar Singh; Tulika Kumari Rai; Vishwa Deepak Tiwari; Aziza Neyaz; Sundaram Pandey; Vivek Kumar Scholar; Paritosh Malaviya; Epco Hasker; Shyam Sundar
Objectives: Monitoring of Leishmania transmission is considered a strategic priority for sustaining elimination of visceral leishmaniasis as a public health problem in the Indian subcontinent. The objective of this study was to evaluate whether serological surveys can distinguish between communities with and without Leishmania transmission, and to assess which serological marker performs best. Methods: Seven villages were selected from Bihar and Uttar Pradesh state, India, and categorized as either currently endemic (CE), previously endemic (PE) or nonendemic (NE). Blood samples were analyzed with the rK39 RDT, direct agglutination test (DAT), and rK39 ELISA. Results: Contrary to the rK39 RDT and DAT, the rK39 ELISA showed a significant difference between all three categories of endemicity, with a seroprevalence of 5.21% in CE villages, 1.55% in PE villages, and 0.13% in NE villages. Even when only looking at the seroprevalence among children aged <10 years, the rK39 ELISA was still able to differentiate between villages with and without ongoing transmission. Conclusion: Our findings suggest the rK39 ELISA to be the most promising marker for monitoring of Leishmania transmission. Further validation is required, and practical, context-adapted recommendations need to be formulated in order to guide policymakers toward meaningful and sustainable surveillance strategies in the post-elimination phase. © 2024 The Author(s)
Optimization of microwave parameters to enhance phytochemicals, antioxidants and metabolite profile of de-oiled rice bran
(Nature Research, 2024) Alonkrita Chowdhury; Alla Yaswanth Naveen Kumar; Rajesh Kumar; Vivek Kumar Maurya; M.S. Mahesh; Abhishek Kumar Singh; Pavan Kumar Yadav; Mayukh Ghosh
The current study explores the effects of microwave treatment at varying wattage and durations on the phytoconstituents, antioxidant status, anti-nutritional factors (ANFs), and metabolite profiles of de-oiled rice bran. The total phenolics and flavonoids showed both increases and decreases depending on specific microwave parameters, while flavonol content consistently increased across all treated groups compared to the control. The DPPH and ABTS free radical scavenging activity, total antioxidant capacity, FRAP, CUPRAC, metal chelating activity, and ascorbic acid content were enhanced in most of the microwaved samples; however, longer microwave exposure at higher wattage led to their reduction. A treatment-specific decrease in ANFs, including condensed tannins, oxalates, and phytates, was observed. HRMS-based untargeted metabolomics identified a diverse range of primary and secondary metabolites, which clustered in a group-specific manner, indicating notable group-wise metabolite variations. Analysis of discriminating metabolites revealed no significant differences in the overall levels of phenolics, flavonoids, vitamins and cofactors, sugars, amino acids, terpenoids, fatty acids, and their derivatives among the treated groups compared to the control; however, several individual metabolites within these metabolite classes differed significantly. These findings suggest that optimized microwaving of de-oiled rice bran can enhance phytochemicals and antioxidants while improving the metabolite profile. © The Author(s) 2024.
Phase and structural nanoarchitectonics of Ce-Doped Sr2SnO4 for improved microwave dielectric and electrical properties
(Springer Science and Business Media Deutschland GmbH, 2025) Upendra Kumar; Satyam Kumar; Abhishek Kumar Singh; Piyush Kumar Sonkar
To support the advancement of layered perovskite ceramics for next-generation wireless and millimeter-wave communication technologies, a series of Sr2Sn1−xCexO4 (x = 0, 0.10, 0.20, 0.30, 0.40, and 0.50) (SSC) were synthesized via the conventional solid-state reaction method, followed by calcination at 1100 °C and sintering at 1300 °C. Structural analysis through X-ray diffraction (XRD) confirmed the formation of a single-phase tetragonal crystal structure (space group I4/mmm) for compositions up to x = 0.20. Beyond this concentration, the emergence of a secondary Sr2CeO4 phase indicated a solubility limit for Ce substitution at the Sn site between x = 0.20 and x = 0.30. This structural evolution was further corroborated by FTIR and Raman spectroscopy, which supported the phase transition and changes in local bonding environments. Microstructural examinations revealed that Ce doping significantly influenced grain morphology and agglomeration tendencies. The coexistence of oxygen vacancies, interstitials, and multivalent cations—namely Sn2+/Sn4+ and Ce2+/Ce3+/Ce4+ played a crucial role in modulating the electrical and microwave dielectric behavior. Dielectric properties were predominantly governed by orientational polarization mechanisms linked to defect dipoles such as () and (). Electrical conduction followed an Arrhenius-type thermally activated process, dominated by doubly ionized oxygen vacancies and mixed ionic–electronic transport through electron exchange at Sn/Ce sites. The microwave dielectric response was primarily driven by electronic polarization, with optimal performance observed at x = 0.20 (ε = 12, Q×f = 23,482, =108 ppm/°C). The synergy between the enhanced electrical and dielectric characteristics underscores the potential of Ce-doped Sr₂SnO₄ (SSC) ceramics for application in intermediate-temperature solid oxide fuel cell (IT-SOFC) electrodes and millimeter-wave communication systems, offering a promising avenue for advanced multifunctional ceramic materials. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2025.
Post kala-azar dermal leishmaniasis: A threat to elimination program
(Public Library of Science, 2020) Mallikarjuna Rao Gedda; Bhawana Singh; Dhiraj Kumar; Abhishek Kumar Singh; Prasoon Madhukar; Shreya Upadhyay; Om Prakash Singh; Shyam Sundar
Leishmaniasis remains a public health concern around the world that primarily affects poor folks of the developing world spanning across 98 countries with mortality of 0.2 million to 0.4 million annually. Post kala-azar dermal leishmaniasis (PKDL) is the late skin manifestation of visceral leishmaniasis (VL). It has been reported that about 2.5% to 20% of patients recovered from VL develop PKDL having stilted macular or nodular lesions with parasites. In the Indian subcontinent (ISC), it manifests a few months after recovery from VL, though in Africa it can occur simultaneously with VL or a little later. New cases of PKDL are also observed without prior VL in the ISC. These individuals with PKDL represent an important but largely neglected reservoir of infection that perpetuates anthroponotic Leishmania donovani transmission in the ISC and can jeopardize the VL elimination program as these cases can infect the sand flies and spread the endemic. Therefore, it becomes imperative to eradicate PKDL as a part of the VL elimination program. With the limited treatment options besides little knowledge on PKDL, this review stands out in focusing on different aspects that should be dealt for sustained VL elimination. © 2020 Gedda et al.
Prevalence of human papillomavirus infection & cervical abnormalities in HIV-positive women in eastern India
(Indian Council of Medical Research, 2016) Jaya Chakravarty; Ankita Chourasia; Minaxi Thakur; Abhishek Kumar Singh; Shyam Sundar; Nisha Rani Agrawal
Background & objectives: India has the third highest burden of HIV and highest number of cervical cancer in the world. A cross-sectional study was performed to determine the prevalence and types of human papillomavirus (HPV) infection, and the factors associated with HPV infection and abnormal cervical cytology in HIV-positive women attending the Antiretroviral Therapy (ART) Centre in a tertiary care hospital in eastern India. Methods: We screened 216 HIV- positive women with Papanicolau smear cytology and HPV testing. HPV DNA was detected by using consensus primers followed by sequencing. Results: Of the 216 HIV-positive women screened, 58 (26.85%) were HPV-positive; 56 (25.9%) were of high-risk (HR) HPV type. The most prevalent HPV type was HPV-16 (7.9%); non 16 and 18 HPV types were present in 17.6 per cent patients. Age ≤ 35 yr [(OR), 2.56 (1.26-5.19)], illiteracy [OR, 2.30 (1.19-4.46)], rural residence [OR, 3.99 (1.27-12.56)] and CD4 ≤350/µl [OR, 2.46 (1.26-4.83)] were associated with increased risk of acquisition of HPV. One hundred thirty nine (74.33%) patients had normal/ negative for intraepithelial lesions (NILM) cytology, three (1.60%) had atypical squamous cells of undetermined significance (ASCUS), 32 (17.11%) had low-grade squamous intraepithelial lesions (LSIL), 10 (5.35%) had high-grade squamous intraepithelial lesions (HSIL) and three (1.60%) had carcinoma cervix. WHO clinical Stage III and IV [OR, 2.83 (1.07-7.49)] and CD4 ≤350/µl [OR, 2.84 (1.30-6.20)] were risk factors for abnormal cytology. Interpretation & conclusions: Our study showed 26.85 per cent HPV positivity in HIV infected women in this region, with HPV-16 as the commonest genotype. Abnormal cervical cytology was seen in about 25 per cent women. Regular Pap smear screening as recommended by the National AIDS Control Organization will help in early detection of cervical abnormalities in HIV- positive women. © 2016, Indian Council of Medical Research. All rights reserved.
Quantitative PCR in Epidemiology for Early Detection of Visceral Leishmaniasis Cases in India
(Public Library of Science, 2014) Medhavi Sudarshan; Toolika Singh; Abhishek Kumar Singh; Ankita Chourasia; Bhawana Singh; Mary E. Wilson; Jaya Chakravarty; Shyam Sundar
Studies employing serological, DTH or conventional PCR techniques suggest a vast proportion of Leishmania infected individuals living in regions endemic for Visceral Leishmaniasis (VL) remain asymptomatic. This study was designed to assess whether quantitative PCR (qPCR) can be used for detection of asymptomatic or early Leishmania donovani infection and as a predictor of progression to symptomatic disease.The study included 1469 healthy individuals living in endemic region (EHC) including both serology-positive and -negative subjects. TaqMan based qPCR assay was done on peripheral blood of each subject using kDNA specific primers and probes.A large proportion of EHC 511/1469 (34.78%) showed qPCR positivity and 56 (3.81% of 1469 subjects) had more than 1 calculated parasite genome/ml of blood. However, the number of individuals with parasite load above 5 genomes/ml was only 20 (1.36% of 1469). There was poor agreement between serological testing and qPCR (k = 0.1303), and 42.89% and 31.83% EHC were qPCR positive in seropositive and seronegative groups, respectively. Ten subjects had developed to symptomatic VL after 12 month of their follow up examination, of which eight were initially positive according to qPCR and among these, five had high parasite load.Thus, qPCR can help us to detect significant early parasitaemia, thereby assisting us in recognition of potential progressors to clinical disease. This test could facilitate early intervention, decreased morbidity and mortality, and possibly interruption of disease transmission. © 2014.