Browsing by Author "Sunil Kumar Singh"

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Comparative transcriptome analysis of Gossypium hirsutum L. in response to sap sucking insects: Aphid and whitefly
(2013) Neeraj Kumar Dubey; Ridhi Goel; Alok Ranjan; Asif Idris; Sunil Kumar Singh; Sumit K. Bag; Krishnappa Chandrashekar; Kapil Deo Pandey; Pradhyumna Kumar Singh; Samir V. Sawant
Background: Cotton (Gossypium hirsutum L.) is a major fiber crop that is grown worldwide; it faces extensive damage from sap-sucking insects, including aphids and whiteflies. Genome-wide transcriptome analysis was performed to understand the molecular details of interaction between Gossypium hirsutum L. and sap-sucking pests, namely Aphis gossypii (Aphid) and Bemisia tabacci (Whiteflies). Roche's GS-Titanium was used to sequence transcriptomes of cotton infested with aphids and whiteflies for 2 h and 24 h.Results: A total of 100935 contigs were produced with an average length of 529 bp after an assembly in all five selected conditions. The Blastn of the non-redundant (nr) cotton EST database resulted in the identification of 580 novel contigs in the cotton plant. It should be noted that in spite of minimal physical damage caused by the sap-sucking insects, they can change the gene expression of plants in 2 h of infestation; further change in gene expression due to whiteflies is quicker than due to aphids. The impact of the whitefly 24 h after infestation was more or less similar to that of the aphid 2 h after infestation. Aphids and whiteflies affect many genes that are regulated by various phytohormones and in response to microbial infection, indicating the involvement of complex crosstalk between these pathways. The KOBAS analysis of differentially regulated transcripts in response to aphids and whiteflies indicated that both the insects induce the metabolism of amino acids biosynthesis specially in case of whiteflies infestation at later phase. Further we also observed that expression of transcript related to photosynthesis specially carbon fixation were significantly influenced by infestation of Aphids and Whiteflies.Conclusions: A comparison of different transcriptomes leads to the identification of differentially and temporally regulated transcripts in response to infestation by aphids and whiteflies. Most of these differentially expressed contigs were related to genes involved in biotic, abiotic stresses and enzymatic activities related to hydrolases, transferases, and kinases. The expression of some marker genes such as the overexpressors of cationic peroxidase 3, lipoxygenase I, TGA2, and non-specific lipase, which are involved in phytohormonal-mediated plant resistance development, was suppressed after infestation by aphids and whiteflies, indicating that insects suppressed plant resistance in order to facilitate their infestation. We also concluded that cotton shares several pathways such as phagosomes, RNA transport, and amino acid metabolism with Arabidopsis in response to the infestation by aphids and whiteflies. © 2013 Dubey et al.; licensee BioMed Central Ltd.
Development of inorganic-organic hybrid nanostructured material for H2O2 sensing application
(Institute of Physics Publishing, 2020) Arvind Kumar; Praveen Kumar Shahi; Amresh Bahadur; Sunil Kumar Singh; Rajiv Prakash; Ram Anjore Yadav; Shyam Bahadur Rai
An organic-inorganic hybrid nanoparticle (HNPs) composed of Sm(TTA)3Phen, a coordination compound, and NaY0.78Er0.02Yb0.20F4, an upconversion nanoparticles (UCNPs), has been developed and used for H2O2 sensing application. Herein, Sm(TTA)3Phen absorbs ultraviolet (UV) light and gives fluorescence in yellow-red-near infrared (NIR) region. Whereas, the UCNPs absorb NIR radiations (980 nm) and consequently emit in green-red region through photon upconversion process. Two important optical phenomena are observed when HNPs are simultaneously excited with UV (266 nm) and NIR (980 nm) laser radiation- (i) an energy transfer from Sm3+ to Er3+ ions, and (ii) color tunable emission from red to green, if the power of 980 nm laser is varied. Further, the material is highly competent to sense H2O2 through fluorescence quenching of Sm3+ emission in presence of H2O2. The nature of quenching is conspicuously different for different concentration/volume range of H2O2. For lower volume range, the rate of decrease of emission/excitation intensity is linear, while for higher volume range the decay in intensity is exponential. The attained minimum detection limit for H2O2 is 2 μl, which is significant for sensing applications. © 2020 The Author(s). Published by IOP Publishing Ltd.
Effect of Mn2+ doping and DDAB-assisted postpassivation on the structural and optical properties of CsPb(Cl/Br)3 halide perovskite nanocrystals
(Institute of Physics, 2024) Charu Dubey; Anjana Yadav; Santosh Kachhap; Sunil Kumar Singh; Govind Gupta; Satendra Pal Singh; Akhilesh Kumar Singh
Cesium lead halide perovskite (CsPbX3; X = Cl, Br, I) nanocrystals showing intense band-edge emission and high photoluminescence quantum yield are known to be a potential candidate for application in optoelectronic devices. However, controlling toxicity due to the presence of Pb2+ in lead-based halide perovskites is a major challenge for the environment that needs to be tackled cautiously. In this work, we have partially replaced Pb2+ with Mn2+ ions in the CsPb(Cl/Br)3 nanocrystals and investigated their impact on the structural and optical properties. The Rietveld refinement shows that CsPbCl2Br nanocrystals possess a cubic crystal structure with Pm 3 ̅ m space group, the Mn2+ doping results in the contraction of the unit cell. The CsPb(Cl/Br)3: Mn nanocrystals show a substantial change in the optical properties with an additional emission band at ∼588 nm through a d-d transition, changing the emission color from blue to pink. Here, a didodecyldimethylammonium bromide (DDAB) ligand that triggers both anion and ligand exchange in the CsPb(Cl/Br)3: Mn nanocrystals have been used to regulate the exchange reaction and tune the emission color of halide perovskites by changing the peak position and the PL intensities of band-edge and Mn2+ defect states. We have also shown that oleic acid helps in the desorption of oleylamine capping from the CsPb(Cl/Br)3: Mn nanocrystal surfaces and DDAB, resulting in the substitution of Cl− with Br− as well as provides capping with shorter branched length ligand which led to increase in the overall PL intensity by many folds. © 2024 IOP Publishing Ltd.
Enhanced Red Upconversion Emission, Magnetoluminescent Behavior, and Bioimaging Application of NaSc0.75Er0.02Yb0.18Gd0.05F4@AuNPs Nanoparticles
(American Chemical Society, 2015) Monika Rai; Sunil Kumar Singh; Akhilesh Kumar Singh; Ritika Prasad; Biplob Koch; Kavita Mishra; Shyam Bahadur Rai
The present study reports significant enhancement in the red upconversion emission of Er3+ in NaSc0.8Er0.02Yb0.18F4 upconversion nanoparticles (UCNPs), via a two step process, (i) codoping of Gd3+ ion at Sc3+ site and (ii) attaching gold nanoparticles (AuNPs) at the surface of these codoped nanostructures, and further probes the use of these Gd:UCNPs@AuNPs for bioimaging application. The Gd3+ codoping tailors the particle size (reduces) of UCNPs and bring out Er3+-Yb3+ ion pair in close proximity, which promotes the cross relaxation mechanism and boosts the population in red emitting level 4F9/2. Further, attachment of AuNPs on the surface of UCNPs gives 2-fold advantages, that is, reduction in green band (through resonance energy transfer with efficiency 31.54%) and enhancement in red band (through plasmonic effect). It gives red to green (R/G) ratio nearly 20:1 (almost single band red UC), which is quite promising for imaging application. In addition to this, codoping of Gd3+ enhances the magnetic moment appreciably and the obtained magnetic moment for NaSc0.75Er0.02Yb0.18Gd0.05F4 UCNPs (∼1.7 emu/g) is close to the reported values for bioseparation in case of NPs. This shows the potential of the material for multimodal (optical and magnetic both) imaging application. These magnetoluminescence particles were found safe up to 1 mg/mL dose as assessed by cytotoxicity measurement in human cervical cancer (HeLa) and lung cancer (A549) cells. Ultrafine nanoparticles, transparent, and stable colloidal solution and the unique red UC emission endow these NPs as optical probe for imaging applications. © 2015 American Chemical Society.
Er3+/Yb3+ codoped Gd2O3 nano-phosphor for optical thermometry
(2009) Sunil Kumar Singh; Kaushal Kumar; S.B. Rai
Combustion synthesized Gd2O3: Er3+/Yb3+ nanocrystalline phosphor has been developed and used as a temperature sensor. Frequency upconverted emissions from two thermally coupled excited states 2H11/2 and 4S3/2 of Er3+ centered at 523 and 548 nm in the phosphor pumped by NIR source were recorded in the temperature range 300-900 K. The maximum sensitivity derived from the FIR technique of the green upconversion emission is approximately 0.0039 K-1. The results imply that Er3+/Yb3+ codoped Gd2O3 phosphor can play an important role in high temperature measurements with a better sensitivity. © 2008 Elsevier B.V. All rights reserved.
In silico analysis and expression profiling of S-domain receptor-like kinases (SD-RLKs) under different abiotic stresses in Arabidopsis thaliana
(BioMed Central Ltd, 2021) Raju Mondal; Subhankar Biswas; Akanksha Srivastava; Suvajit Basu; Maitri Trivedi; Sunil Kumar Singh; Yogesh Mishra
Background: S-domain receptor-like kinases (SD-RLKs) are an important and multi-gene subfamily of plant receptor-like/pelle kinases (RLKs), which are known to play a significant role in the development and immune responses of Arabidopsis thaliana. The conserved cysteine residues in the extracellular domain of SD-RLKs make them interesting candidates for sensing reactive oxygen species (ROS), assisting oxidative stress mitigation and associated signaling pathways during abiotic stresses. However, how closely SD-RLKs are interrelated to abiotic stress mitigation and signaling remains unknown in A. thaliana. Results: This study was initiated by examining the chromosomal localization, phylogeny, sequence and differential expression analyses of 37 SD-RLK genes using publicly accessible microarray datasets under cold, osmotic stress, genotoxic stress, drought, salt, UV-B, heat and wounding. Out of 37 SD-RLKs, 12 genes displayed differential expression patterns in both the root and the shoot tissues. Promoter structure analysis suggested that these 12 SD-RLK genes harbour several potential cis-regulatory elements (CREs), which are involved in regulating multiple abiotic stress responses. Based on these observations, we investigated the expression patterns of 12 selected SD-RLKs under ozone, wounding, oxidative (methyl viologen), UV-B, cold, and light stress at different time points using semi-qRT-PCR. Of these 12 SD-SRKs, the genes At1g61360, At1g61460, At1g61380, and At4g27300 emerged as potential candidates that maintain their expression in most of the stress treatments till exposure for 12 h. Expression patterns of these four genes were further verified under similar stress treatments using qRT-PCR. The expression analysis indicated that the gene At1g61360, At1g61380, and At1g61460 were mostly up-regulated, whereas the expression of At4g27300 either up- or down-regulated in these conditions. Conclusions: To summarize, the computational analysis and differential transcript accumulation of SD-RLKs under various abiotic stresses suggested their association with abiotic stress tolerance and related signaling in A. thaliana. We believe that a further detailed study will decipher the specific role of these representative SD-RLKs in abiotic stress mitigation vis-a-vis signaling pathways in A. thaliana. © 2021, The Author(s).
In silico characterization, molecular phylogeny, and expression profiling of genes encoding legume lectin-like proteins under various abiotic stresses in Arabidopsis thaliana
(BioMed Central Ltd, 2022) Subhankar Biswas; Raju Mondal; Akanksha Srivastava; Maitri Trivedi; Sunil Kumar Singh; Yogesh Mishra
Background: Lectin receptor-like kinases (Lec-RLKs), a subfamily of RLKs, have been demonstrated to play an important role in signal transduction from cell wall to the plasma membrane during biotic stresses. Lec-RLKs include legume lectin-like proteins (LLPs), an important group of apoplastic proteins that are expressed in regenerating cell walls and play a role in immune-related responses. However, it is unclear whether LLPs have a function in abiotic stress mitigation and related signaling pathways. Therefore, in this study, we examined the possible role of LLPs in Arabidopsis thaliana (AtLLPs) under various abiotic stresses. Results: The study was initiated by analyzing the chromosomal localization, gene structure, protein motif, peptide sequence, phylogeny, evolutionary divergence, and sub-cellular localization of AtLLPs. Furthermore, the expression profiling of these AtLLPs was performed using publicly accessible microarray datasets under various abiotic stresses, which indicated that all AtLLPs were differently expressed in both root and shoot tissues in response to abiotic stresses. The cis-regulatory elements (CREs) analysis in 500 bp promoter sequences of AtLLPs suggested the presence of multiple important CREs implicated for regulating abiotic stress responses, which was further supported by expressional correlation analysis between AtLLPs and their CREs cognate transcription factors (TFs). qRT-PCR analysis of these AtLLPs after 2, 6, and 12 h of cold, high light, oxidative (MV), UV-B, wound, and ozone stress revealed that all AtLLPs displayed differential expression patterns in most of the tested stresses, supporting their roles in abiotic stress response and signaling again. Out of these AtLLPs, AT1g53070 and AT5g03350 appeared to be important players. Furthermore, the mutant line of AT5g03350 exhibited higher levels of ROS than wild type plants till 12 h of exposure to high light, MV, UV-B, and wound, whereas its overexpression line exhibited comparatively lower levels of ROS, indicating a positive role of this gene in abiotic stress response in A. thaliana. Conclusions: This study provides basic insights in the involvement of two important representative AtLLPs, AT1g53070 and AT5g03350, in abiotic stress response. However, further research is needed to determine the specific molecular mechanism of these AtLLPs in abiotic stress mitigation and related signaling pathways in A. thaliana. © 2022, The Author(s).
Lanthanide doped ultrafine hybrid nanostructures: Multicolour luminescence, upconversion based energy transfer and luminescent solar collector applications
(Royal Society of Chemistry, 2017) Priyam Singh; Praveen Kumar Shahi; Sunil Kumar Singh; Akhilesh Kumar Singh; Manish Kumar Singh; Rajiv Prakash; Shyam Bahadur Rai
We herein demonstrate novel inorganic-organic hybrid nanoparticles (HNPs) composed of inorganic NPs, NaY0.78Er0.02Yb0.2F4, and an organic β-diketonate complex, Eu(TTA)3Phen, for energy harvesting applications. Both the systems maintain their core integrity and remain entangled through weak interacting forces. HNPs incorporate the characteristic optical behaviour of both the systems i.e. they give an intense red emission under UV excitation, due to Eu3+ in organic complexes, and efficient green upconversion emission of Er3+ in inorganic NPs for NIR (980 nm) excitation. However, (i) an energy transfer from Er3+ (inorganic NPs) to Eu3+ (organic complex) under NIR excitation, and (ii) an increase in the decay time of 5D0 → 7F2 transition of Eu3+ for HNPs as compared to the Eu(TTA)3Phen complex, under different excitation wavelengths, are added optical characteristics which point to an important role of the interface between both the systems. Herein, the ultra-small size (6-9 nm) and spherical shape of the inorganic NPs offer a large surface area, which improves the weak interaction force between both the systems. Furthermore, the HNPs dispersed in the PMMA polymer have been successfully utilized for luminescent solar collector (LSC) applications. © The Royal Society of Chemistry 2017.
Melatonin regulates splenocytes proliferation via IP3-dependent intracellular Ca2+ release in seasonally breeding bird, Perdicula asiatica
(Informa Healthcare, 2014) Sanjeev Kumar Yadav; Chandana Haldar; Sunil Kumar Singh; Debabrata Dash
Melatonin plays an important role in the immune regulation of birds. Both endogenous and exogenous melatonin modulates lymphocyte proliferation via its specific membrane receptors, Mel1a, Mel1b and Mel1c, though the mechanisms behind this process are poorly understood. We investigated the differences in melatonin membrane receptor Mel1a, Mel1b and Mel1c expression by western blot and reverse transcription reaction and the in vitro effect of melatonin on the intracellular Ca2+ concentration ([Ca2+]i) in splenocytes of the Indian Jungle Bush Quail, Perdicula asiatica. We used a non-selective melatonin receptor antagonist for Mel1a and Mel1b, luzindole, and the selective Mel1b blocker, 4P-PDOT to check the specific role of melatonin receptor on ([Ca2+]i). The expression of Mel1a, Mel1b and Mel1c receptors mRNA and protein was upregulated by melatonin (10-7M) with a significant high rise in ([Ca2+]i), which was differentially blocked by supplementation of antagonist, luzindole (10-7M) and 4P-PDOT (10-7M). Furthermore, we noted in vitro effect of melatonin and 2-aminoethoxydiphenyl borate (2-APB), a cell-permeable antagonist of inositol 1, 4, 5-trisphosphate (IP3) receptor to check the rise in ([Ca2+]i) through the IP3 pathway. Significantly low ([Ca2+]i) was noted in melatonin and 2-APB pretreated splenocytes when compared with splenocytes where 2-APB was absent. Thus, our data suggest that melatonin through its membrane receptor induced the elevation of ([Ca2+]i) via IP3-dependent pathway for splenocyte proliferation in P. asiatica. © 2014 Informa Healthcare USA, Inc.
Multi-stimuli-responsive and dynamic color tunable security ink for multilevel anticounterfeiting
(Institute of Physics, 2023) Charu Dubey; Anjana Yadav; Diksha Baloni; Sachin Singh; Anjani Kumar Singh; Sunil Kumar Singh; Akhilesh Kumar Singh
Luminescent security features have been used for anticounterfeiting for a long time. However, constant effort is required to strengthen these security features to be ahead of counterfeiters. Here, we developed a multi-stimuli-responsive luminescent security ink containing Tb(ASA)3Phen, K2SiF6:Mn4+, and NaYF4:Yb3+/Er3+ luminescent materials in PVC gold medium. Tb(ASA)3Phen complex shows a broad excitation band in the UV region; upon UV light radiation it shows strong greenish emission of Tb3+ ions through the antenna effect. K2SiF6:Mn4+, on the other hand, has three excitation bands with maxima at 248, 354, and 454 nm which emit red light after excitation through these bands. NaYF4:Yb3+/Er3+ is used as an upconverting nanophosphor showing green emission under 976 nm laser excitation. Thus, the multi-stimuli-responsive luminescent security ink shows greenish, red, and green emissions under 367 nm, 450 nm, and 976 nm excitations, respectively. Furthermore, the distinct lifetimes of the activators in Tb(ASA)3Phen and K2SiF6:Mn4+, i.e. 0.1708 ms and 8.165 ms, respectively, under 380 nm excitation make this ink suitable for dynamic anticounterfeiting as well. The ink shows a change in the emission color with time delay, after the removal of the 380 nm excitation source, from greenish yellow (at 0 delays) to reddish color after a delay of 7.5 ms. These unique optical features along with excellent photo-, chemical- and environmental stability make this ink useful for advanced-level anticounterfeiting. © 2023 IOP Publishing Ltd.
Nanotechnology applications in pandemic prediction
(Elsevier, 2025) Nandita Singh; Kalyani Dewangan; Jitendra Sahu; Uday Pratap Azad; Divyanshu Singh; Sweta Bhagat; Ashish Kumar Singh; Suryabhan Singh; Sunil Kumar Singh; Ananya Srivastava; Divya Pratap Singh
The necessity for novel ways utilizing nanotechnology in antiviral tactics is demonstrated by the continuous fight against viral infections, which has been brought to light by the COVID-19 outbreak. With so many potential applications-biosensors, vaccines, disinfectants, and nanoparticles/functionalized nanoparticles have become increasingly attractive tool in the battle against viral epidemics. The function of nanoparticles in pandemic control is assessed in this book chapter, and their possible uses, advantages, and drawbacks are examined. The significance of nanotechnology in managing viral outbreaks, namely in vaccine development, is the first topic we cover. Although the use of metallic nanoparticles to functionalize protective face masks has become popular as a sustainable substitute for throwaway masks, improving virus filtering and cutting down on waste generation, incorrect disposal of these masks might pollute the environment and even cause ecological damage. In our second section, we will discuss various types of nanoparticles or functionalized nanoparticles-based sensors to detect the pandemic associated viruses at very early stage. For this purpose, along with various types of nanoparticle based-sensors, the selection of appropriate electrochemical techniques is also equally important for the better performance of the constructed biosensors. Along with COVID-19 we will discuss other pandemics such as swine flu, HIV/AIDS, and black death. We must reduce such possible dangers and environmental effects in order to properly control outbreaks. For this reason, it is essential to comprehend the benefits and drawbacks of using nanoparticles while creating efficient plans for controlling pandemics moving forward. © 2025 Elsevier Inc. All rights reserved.
New perspective in garnet phosphor: Low temperature synthesis, nanostructures, and observation of multimodal luminescence
(American Chemical Society, 2014) Kavita Mishra; Sunil Kumar Singh; Akhilesh Kumar Singh; Monika Rai; Bipin Kumar Gupta; Shyam Bahadur Rai
Herein, we report a new concept for garnet materials in terms of the synthesis of nanocrystalline structure at low temperatures and its multimodal luminescence processes. Terbiumand ytterbium-ion-codoped yttrium gallium garnet nanophosphors have been synthesized via solution combustion technique; nearly pure phase nanophosphor samples were obtained. The synthesized nanophosphor shows efficient multimodal upconversion (UC), downshifting (DS), and quantum cutting (QC)/downconversion (DC) luminescence, which is a new paradigm in garnet material. The garnet nanophosphor shows strong green emission through DS and UC processes both. Furthermore, cooperative energy transfer (CET) has been described in detail, and a possible mechanism for the QC process is also proposed. A UV/blue photon absorbed by Tb3+ ion splits into two near-infrared photons (wavelength range 900-1040 nm), emitted by a Yb3+ ion pair, with an efficiency of more than 100%. The Yb3+ concentration dependent ET from Tb3+ to Yb3+ has been verified using time domain analysis. An ET efficiency as high as 28% and a corresponding QC efficiency of about 128% (for 15 mol % of Yb3+ concentration) have been attained. Such a multimode emitting nanophosphor could be very useful in display devices and for enhancing the conversion efficiency of next generation solar cells via spectral modification etc. © 2014 American Chemical Society.
Preparation and characterization of a mercury based Indian traditional drug- Ras-Sindoor
(2009) Sunil Kumar Singh; Anand Chaudhary; D.K. Rai; S.B. Rai
The mercury based Indian traditional drug Ras-Sindoor is administered for the various ailments such as syphilis, genital disorders, and for rejuvenation. Pharmaceutical processing of Ras-Sindoor involves treating metallic mercury with sulfur and the juice of the aerial root of Banyan tree (Ficus benghalensis Linn.) and then controlled intermittent heating so that the metallic state is transformed into the corresponding sulfide form. In the study, synthesis and systematic characterization of this drug using various techniques, viz. X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), far infrared spectroscopy (FIR), Fourier transform infrared spectroscopy (FTIR), differential thermal analysis (DTA), thermogravimetry analysis (TGA), energy dispersive X-ray analysis (EDAX) and atomic absorption spectroscopy (AAS) have been reported. Drug contains mercury in the mercury sulfide form (Hg2+) being nanocrystalline (20-50 nm) in nature and associated with the organic contents of the aerial root of the Ficus benghalensis Linn. Some specific findings were also made which could be of help for the interpretation of therapeutic value, none-toxicity of Ras-Sindoor and for the standardization of such kind of traditional herbo-metallic drugs.
Quality control of herbal medicines by using spectroscopic techniques and multivariate statistical analysis
(2010) Sunil Kumar Singh; Sunil Kumar Jha; Anand Chaudhary; R.D.S. Yadava; S.B. Rai
Herbal medicines play an important role in modern human life and have significant effects on treating diseases; however, the quality and safety of these herbal products has now become a serious issue due to increasing pollution in air, water, soil, etc. The present study proposes Fourier transform infrared spectroscopy (FTIR) along with the statistical method principal component analysis (PCA) to identify and discriminate herbal medicines for quality control. Herbal plants have been characterized using FTIR spectroscopy. Characteristic peaks (strong and weak) have been marked for each herbal sample in the fingerprint region (400-2000cm -1). The ratio of the areas of any two marked characteristic peaks was found to be nearly consistent for the same plant from different regions, and thus the present idea suggests an additional discrimination method for herbal medicines. PCA clusters herbal medicines into different groups, clearly showing that this method can adequately discriminate different herbal medicines using FTIR data. Toxic metal contents (Cd, Pb, Cr, and As) have been determined and the results compared with the higher permissible daily intake limit of heavy metals proposed by the World Health Organization (WHO). © 2010 Informa UK Ltd.
Retraction Note: Anti-Thrombotic Effects of Selective Estrogen Receptor Modulator Tamoxifen (Thromb Haemost (2011) 106:4 (624–635) DOI: 10.1160/TH11-03-0178)
(Georg Thieme Verlag, 2025) Manasa K. Nayak; Sunil Kumar Singh; Arnab Roy; Vivek Prakash; Anand Kumar; Debabrata Dash
The Editors and Publisher of Thrombosis and Haemostasis retract the article “Anti thrombotic Effects of Selective Estrogen Receptor Modulator Tamoxifen” by Manasa K. Nayak, Sunil K. Singh, Arnab Roy, Vivek Prakash, Anand Kumar, and Debabrata Dash published in Volume 106, Number 04, pages 624–635 (doi: 10.1160/TH11-03-0178), due to concerns regarding image integrity (first raised on PubPeer https://pubpeer.com/publications/654251ED5CBF71EB87D339EBF16C2D) and incomplete methodol ogy. Specifically, replacement imagesfor Figure4didnotresolveissuesofsplicing, and revised images for Figure6 failed toclarify the identification of dense granules. Additionally, critical methodological details required for reproducibility were not provided despite multiple requests. These concerns undermine the confidence of the editors in the findings presented. The authors disagree with this retraction. © 2025 Georg Thieme Verlag. All rights reserved.
Revelation of the Technological Versatility of the Eu(TTA)3Phen Complex by Demonstrating Energy Harvesting, Ultraviolet Light Detection, Temperature Sensing, and Laser Applications
(American Chemical Society, 2015) Praveen Kumar Shahi; Akhilesh Kumar Singh; Sunil Kumar Singh; Shyam Bahadur Rai; Bruno Ullrich
We synthesized the Eu(TTA)3Phen complex and present herein a detailed study of its photophysics. The investigations encompass samples dispersed in poly(vinyl alcohol) and in ethanol in order to explore the versatile applicability of these lanthanide-based materials. Details upon the interaction between Eu, TTA, and the Phen ligands are revealed by Fourier transform infrared and UV-visible absorption, complemented by steady state and temporally resolved emission studies, which provide evidence of an efficient energy transfer from the organic ligands to the central Eu3+ ion. The material produces efficient emission even under sunlight exposure, a feature pointing toward suitability for luminescent solar concentrators and UV light sensing, which is demonstrated for intensities as low as 200 nW/cm2. The paper further promotes the complex's capability to be used as luminescence-based temperature sensor demonstrated by the considerable emission intensity changes of ∼4.0% per K in the temperature range of 50-305 K and ∼7% per K in the temeperature range 305-340 K. Finally, increasing the optical excitation causes both spontaneous emission amplification and emission peak narrowing in the Eu(TTA)3Phen complex dispersed in poly(vinyl alcohol) - features indicative of stimulated emission. These findings in conjunction with the fairly large stimulated emission cross-section of 4.29 × 10-20 cm2 demonstrate that the Eu(TTA)3Phen complex dispersed in poly(vinyl alcohol) could be a very promising material choice for lanthanide-polymer based laser architectures. (Graph Presented). © 2015 American Chemical Society.
Role of ACE inhibitors in anthracycline-induced cardiotoxicity: A randomized, double-blind, placebo-controlled trial
(John Wiley and Sons Inc., 2018) Vineeta Gupta; Sunil Kumar Singh; Vikas Agrawal; Tej Bali Singh
Background: Several measures including drugs have been tried to reduce anthracycline cardiotoxicity. The lack of randomized trials prompted this study to assess the role of an angiotensin converting enzyme (ACE) inhibitor (enalapril) in anthracycline-induced cardiotoxicity in children with hematological malignancies. Methods: A randomized, double-blind, placebo-controlled trial was conducted on 84 patients with leukemia (41) and lymphoma (43) who received anthracyclines (doxorubicin and/or daunorubicin) at cumulative dose ≥200 mg/m 2 . The patients were randomized to receive either enalapril [group A (n = 44)] or placebo [group B (n = 40)] for 6 months. Left ventricular ejection fraction (LVEF) and cardiac biomarkers (cardiac troponin I [cTnI], probrain natriuretic peptide [proBNP], and creatine kinase MB [CK-MB]) were assessed at baseline and 6 months. The primary outcome was a measured decrease in LVEF (≥20%). Secondary outcome measures were changes in cardiac biomarkers and the development of heart failure or arrhythmias. Results: LVEF decreased in both groups at 6 months, more so in group B (62.25 ± 5.49 vs 56.15 ± 4.79, P < 0.001). A ≥20% decrease was seen in 3 patients in group B but none in group A (P = 0.21). Cardiac biomarkers increased more in group B at 6 months, and the increase was significant for proBNP (49.60 ± 35.97 vs 98.60 ± 54.24, P < 0.001) and cTnI (0.01 ± 0.00 vs 0.011 ± 0.003, P = 0.035) but not significant for CK-MB (1.08 ± 0.18 vs 1.21 ± 0.44, P = 0.079). In group A, 9.1% of the patients showed an increase in proBNP level ≥100 compared with 37.5% in group B (P < 0.001). No patient developed heart failure or arrhythmia. Conclusion: Enalapril has a role in reducing cardiac toxicity after anthracycline administration. © 2018 Wiley Periodicals, Inc.
Substantial invasion of Antarctic Intermediate Water into the Arabian Sea during Younger Dryas and Heinrich Stadials
(Elsevier Ltd, 2025) Arvind Shukla; Tapas Kumar Mishra; Sunil Kumar Singh; Arun Deo Singh
Antarctic Intermediate Water (AAIW) is an important component of the global thermohaline circulation and an essential limb of the Atlantic Meridional Overturning Circulation (AMOC), which redistributes heat, oxygen, and nutrients in the global ocean. Understanding the dynamics of intermediate water circulation over a millennial timeframe is essential to determine the impact of AMOC changes on ocean heat transport during abrupt climatic events. However, the precise relationship between global ocean intermediate water circulation and abrupt climate events, such as the Younger Dryas (YD) and Heinrich Stadials (HS), is not yet fully understood, particularly in tropical regions. Here, we present a ∼29 ka high-resolution record of Neodymium isotope (ƐNd) in authigenic phases, a water mass tracer, of a sediment core collected from the intermediate depth (840 m) in the eastern Arabian Sea (off Goa) to understand the past variability in AAIW circulation in the northern Indian Ocean on a millennial time scale. Our new ƐNd record reveals the pronounced temporal variation (−9.5 to −6.1) throughout the core, marked with enhanced radiogenic Nd signature during the YD, HS1, and HS2. These episodes of enhanced radiogenic Nd signatures signify an increased northward penetration of Antarctic Intermediate Water into the Northern Indian Ocean. The intervals of northward progression of AAIW coincide with the Northern Hemisphere cold events which could have resulted from the enhanced formation of AAIW in the Southern Ocean that occurred due to the warming-induced deceleration of the AMOC. This correlation underscores a robust connection between the formation of North Atlantic Deep Water (NADW) and Southern Ocean climate dynamics through the “bipolar seesaw” mechanism. Our study emphasizes that tracking changes in AAIW in the Arabian Sea can provide insights into the past and future variations in AMOC. © 2024 Elsevier Ltd
Temperature sensing using bulk and nanoparticles of Ca0.79Er0.01Yb0.2MoO4phosphor
(Institute of Physics, 2022) Sachin Singh; Santosh Kachhap; Akhilesh Kumar Singh; Sasank Pattnaik; Sunil Kumar Singh
Optical temperature sensing is widely realized by using upconversion (UC) emission in lanthanide-doped phosphors. There are various parameters that are responsible for UC intensity of the phosphor like particle shape and size, type of symmetry that exist at the site position, distribution of lanthanide ions in the phosphor, and so on. However, a comparative study of the bulk and nanostructure on the temperature sensing ability of such phosphor is rare. In the present work, we have taken Ca0.79Er0.01Yb0.2MoO4 phosphors as a model system and synthesized its bulk (via solid-state reaction method, named SCEY) and nanostructures (via solution combustion route, named CCEY). We further studied their phase, crystal structure, phonon frequency, optical excitation, and emission (upconversion & downshifting) properties. Finally, the optical temperature sensing behavior of SCEY and CCEY, in the range 305 K-573 K, have been compared. The maximum relative sensitivity of the phosphor SCEY and CCEY are 0.0061 K-1 at 305 K and 0.0094 K-1 at 299 K, respectively, while, the maximum absolute sensitivities are 0.0150 K-1 at 348 K, and 0.0170 K-1 at 398 K, respectively. We thus conclude that the temperature sensing ability of nanoparticle-based Ca0.79Er0.01Yb0.2MoO4 phosphor is better compared to its bulk phosphor. © 2022 IOP Publishing Ltd.