Browsing by Author "Himanshu Mishra"

Now showing 1 - 20 of 29

2D materials for flexible electronics
(Elsevier, 2022) Suyash Rai; Himanshu Mishra; Vijay K Singh; Tejendra K Gupta; Anchal Srivastava
Since the breakthrough of graphene, two-dimensional (2D) materials have attracted immense research interest due to their unique electronic, optical, and mechanical properties, holding great potential for harnessing their applications in next-generation electronics, optoelectronics, and biomedical fields. The most striking feature of 2D materials is their atomic thickness, which makes them feasible to adhere to any kind of surface without losing much of their inherent properties. With this advantage, 2D materials can be integrated into various flexible and stretchable electronic devices in a conventional and scalable fashion. Here in this chapter the synthesis of 2D materials using different top-down and bottom-up methods followed by various efficient transfer methods has been discussed thoroughly. After that, state-of-the-art flexible device applications of 2D materials in electronics, sensors, and energy storage devices, along with their future possibilities, are discussed. © 2023 Elsevier Ltd. All rights reserved.
A curious observation of Pauli-Blocking in MoS2-quantum dots/graphene hybrid system
(American Institute of Physics Inc., 2018) Amulya Nemoori; Himanshu Mishra; Vijay Kumar Singh; P.K. Shukla; Anchal Srivastava; Amritanshu Pandey
In this study, Pauli-Blocking has been observed in a 0D/2D MoS2 quantum dots/graphene (MoS2-QDs/graphene) hybrid system. For the observation of room temperature Pauli-Blocking in the 0D/2D system, a photodetector device based on n-type MoS2-QDs and CVD grown graphene has been fabricated using a facile and lithography free technique. The current-voltage characteristics of the device have been performed at room temperature. The fabricated device shows a negative response under visible light (λ ∼ 400 to 700 nm) illumination. The dark to photo current ratio of the device shows variation up to two orders of magnitude. This negative response, which results decrease in current under visible light illumination, may be attributed to the Pauli-Blocking due to high absorbance of photon energy in visible light range. Furthermore, it is believed that the present study may provide an insight into understanding the Pauli-Blocking in 0D/2D hybrid system at room temperature. © 2018 Author(s).
A randomized prospective study of concurrent chemo-radiotherapy vs accelerated hyperfractionation in advanced cancer of head and neck
(Journal of Clinical and Diagnostic Research, 2016) Himanshu Mishra; Ritusha Mishra; Uday Prataap Shahi; Abhijit Mandal
Introduction: Locally advanced unresectable squamous cell carcinoma of head and neck has poor locoregional control when treated with conventionally fractionated Radiation Therapy (RT) alone. However, Concurrent Chemo-Radiotherapy (CRT) and altered fractionated RT schedules like Accelerated Hyperfractionation (AHF) are two different treatment strategies that have shown to be associated with better efficacy as compared to conventional RT alone in such cases. Aim: Aim of the study was to compare these two treatment strategies i.e., CRT and AHF radiation treatment to know which is better in terms of clinical outcome and toxicity in patients of locally advanced unresectable squamous cell carcinoma of head and neck. Materials and Methods: A prospective randomized trial was done to compare the effect of CRT and of AHF radiation treatment in locally advanced unresectable head and neck cancer on 15 patients in each arm and followed up over three months period. Results: At the end of three months after completion of treatment protocol, complete response was 62% in CRT arm and 53% in AHF arm. In CRT arm and AHF arm, Grade 3 skin reactions were observed in 100% and 87%, grade 3 mucosal reactions were in 62% and 67% of cases, respectively. Three patients died in CRT arm (two due to myelosuppression and associated infection; one during the treatment and another after two weeks of treatment completion. The third patient expired after one month of treatment completion at his native place due to unknown reason). One patient died in AHF arm (during treatment due to cardiac event). Conclusion: Efficacy of AHF was comparable to CRT with lesser toxicity. So the present study suggests that AHF should be preferred over CRT in locally advanced, unresectable, squamous cell head and neck cancer followed over three months non-treatment period. © 2016, Journal of Clinical and Diagnostic Research. All rights reserved.
Animal-Based Food Waste and By-product Utilization
(Springer Science+Business Media, 2025) M. Kumar Singh; Himanshu Mishra; Prajasattak Kanetkar; Arvind P. Kumar; Vishal Kumar; Pawan Katole
Production and post-production processes in meat, dairy, and fish industries produce large quantities of waste and different by-products. These materials are generally discarded without any significant utilization by humans. Meat industry waste products such as liver, kidney, heart, stomach, tongue, blood, bone, etc., are rich in nutrition required for humans (as diet), animals (as feed), and soil (as fertilizer). In the dairy industry, whey (cheese), skim milk (cream), ghee residue (ghee), buttermilk (Chhach), etc., are the by-products of production line. All these by-products are composed of high nutritional components such as proteins, unsaturated fats, minerals, bioactive peptides, etc. Fishery industry waste is rich in collagen and omega-3 fatty acid content. These precious wastes need to be utilized without exposing them directly to the surroundings. Without processing, the high content of insoluble organic (blood compositions, wastewater, etc.) waste items also acts as an environmental hazard. High rate of mineral deposition in soil causes toxicity effects on human, plant, and marine ecology. So this chapter is focused on nutritional values and processing of the waste material for decreasing waste and converting waste to wealth. © 2025 The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG.
Bioactive metabolites identification of the foxnut and broken millet-based nutritional bar using HR-MS
(Elsevier B.V., 2024) Vishal Kumar; Arvind Kumar; Manish Kumar Singh; Priya Dhyani; Himanshu Mishra; Dinesh Chandra Rai
The by-products of the grain processing industry are a vital resource for the valorization methods in the food industry. In comparison to the whole grain, the broken kernels and seeds own similar nutrient and bioactive compounds having multifaceted health properties. This study aims to develop a nutritional bar by utilizing the by-products from barnyard millet and foxnut with added sweeteners. Furthermore, high-resolution mass spectrometry (HR-MS) metabolomics was carried out in positive and negative both ion modes to identify the major bioactive compounds formed in the matrix of the best-optimized valorized bar. The formulation of the bar having 15 % foxnut flour and the barnyard flour each, was elucidated highest rheological and sensory scores. A sum of 29 bioactive metabolites has been observed in the obtained metabolome. Major metabolites were palmitoyl serinol, glycitein, persin, bufagargarizin, apigenin, carvone, etc. covering a wide area in the mass spectrum. The therapeutic value of these compounds is heart health promotion, anti-inflammatory, anti-carcinogenic, anti-diabetic, anti-microbial, etc. This work highlights the bioactivity of the valorized nutritional bar employing robust and accurate tool of mass spectrometry. The developed snack is a functional food for the consumers. © 2024 The Author(s)
Carbon nanotubes molybdenum disulfide 3D nanocomposite as novel nanoscaffolds to immobilize Lens culinaris β-galactosidase (Lsbgal): Robust stability, reusability, and effective bioconversion of lactose in whey
(Elsevier Ltd, 2019) Anjali Yadav; Sumit Kumar Pandey; Dinesh Chand Agrawal; Himanshu Mishra; Anchal Srivastava; Arvind M. Kayastha
Multiwalled carbon nanotubes molybdenum disulfide 3D nanocomposite (MWCNT-MoS2 NC) was successfully synthesized via eco-friendly hydrothermal method. The microstructural characterization of synthesized nanocomposite was carried out using different spectroscopic and microscopic techniques. Nanocomposite was activated using glutaraldehyde chemistry and used as a platform to immobilize Lens culinaris β-galactosidase (Lsbgal) which resulted in 93% of immobilization efficiency. Attachment of Lsbgal onto nanocomposite was confirmed by AFM, FE-SEM, FTIR, and CLSM. The nanobiocatalyst showed broadening in operational pH and temperature working range. Remarkable increase in thermal stability was observed as compared to soluble enzyme. Nanobiocatalyst showed outstanding increase in storage stability, retained 92% of residual activity over a period of 8 months. This offers good reusability as it retained ∼50% residual activity up to 21 reuses and exhibited higher rate of lactose hydrolysis in whey. MWCNT-MoS2 NC conjugated to biomolecules can serve as a potential platform for fabrication of lactose biosensor. © 2019 Elsevier Ltd
Clinical Applications of Hyperthermia
(wiley, 2023) Himanshu Mishra; Ritusha Mishra; Abhijit Mandal
Temperature in the supra-physiological range has been successfully used to treat tumors across various clinical sites. Hyperthermia (HT) is mostly used in combination with other treatment modalities like radiotherapy (RT), chemotherapy (CT), chemo-radiotherapy (CRT), andimmunotherapy. HT augments the effect of RT by vasodilation, damage to intracellular components of tumor, and causing cytotoxicity in radioresistant phases of cell cycle. The cytotoxicity of chemotherapeutic agents is also enhanced with HT, as it increases their cellular uptake. As a wide range of immune response is triggered by HT, integration of immunotherapy with HT has a good potential scope in cancer management. Adverse effects of HT mainly depend on the type of target organ, technique, and device being used. Soft tissue and skin burns are most commonly observed adverse effects. Although several studies have shown clinical benefits of HT, more robust, phase III, prospective randomized trials are required to validate the data and to optimize different treatment strategies in combination with HT. © 2024 John Wiley & Sons Ltd.
Clinico.epidemiological profile and treatment outcome in adolescents and young patients of rectal cancer attending a tertiary cancer center
(Wolters Kluwer Medknow Publications, 2023) Ritusha Mishra; Ankita Pandey; Himanshu Mishra; Tej B. Singh; Abhijit Mandal; Anupam K. Asthana
Introduction: The incidence of colorectal cancer in young adults is on an increasing trend. It is observed that this subgroup of patients has an aggressive disease and carries a poorer prognosis compared to its older counterpart. This study aimed to analyze the incidence, treatment outcome, and prognostic factors in adolescents and young adults with rectal cancer attending a tertiary cancer center in North India. Materials and Methods: We retrospectively analyzed 50 patients of histologically proven rectal cancer, aged up to 30 years, treated at our center between 2015 and 2019. The clinical, demographic, and pathological parameters were studied in all these patients. Kaplan-Meier survival analysis was used to find out survival. Univariate analysis was performed to assess prognostic factors. Results: The incidence was 26.4% at our center with a median age of 28 years. Bleeding per rectum was the commonest complaint. Most of them had signet ring cell histology (26%). The median overall survival was 16 months. Survival was significantly better in patients having bleeding per rectum as an initial complaint (P = 0.009), absence of lymphovascular invasion (LVI) (P = 0.005), and perineural invasion (PNI) (P = 0.002), who received complete planned treatment compared to patients who could not receive either of the modality (P < 0.001). Patients who did not receive radiotherapy (RT) had the worst outcomes compared to those who received RT in any form. RT dose of 50.4 Gy was found to be superior as compared to other schedules. There was no significant difference in survival with gender, tumor stage, grade, type of surgery, or chemotherapy regimen. Conclusion: The majority of patients presented in an advanced stage. Therefore, bleeding per rectum should be properly and timely investigated in all these young patients. Early detection and complete treatment are paramount to improving the outcome. © 2023 Copyright:
Comparative analysis of simultaneous integrated boost and sequential boost radiotherapy in node-positive cervical cancer: dosimetric and radiobiological considerations
(Springer Science and Business Media Deutschland GmbH, 2024) Ritusha Mishra; Shreya Singh; Ganesh Patel; Abhijit Mandal; Himanshu Mishra; Ankita Pandey; Bajarang Bahadur; Pramod Kumar Singh; Shikha Sachan; Mallika Tewari
For locally advanced cervical cancer, the standard therapeutic approach involves concomitant chemoradiation therapy, supplemented by a brachytherapy boost. Moreover, an external beam radiotherapy (RT) boost should be considered for treating gross lymph node (LN) volumes. Two boost approaches exist with Volumetric Intensity Modulated Arc Therapy (VMAT): Sequential (SEQ) and Simultaneous Integrated Boost (SIB). This study undertakes a comprehensive dosimetric and radiobiological comparison between these two boost strategies. The study encompassed ten patients who underwent RT for cervical cancer with node-positive disease. Two sets of treatment plans were generated for each patient: SIB-VMAT and SEQ-VMAT. Dosimetric as well as radiobiological parameters including tumour control probability (TCP) and normal tissue complication probability (NTCP) were compared. Both techniques were analyzed for two different levels of LN involvement – only pelvic LNs and pelvic with para-aortic LNs. Statistical analysis was performed using SPSS software version 25.0. SIB-VMAT exhibited superior target coverage, yielding improved doses to the planning target volume (PTV) and gross tumour volume (GTV). Notably, SIB-VMAT plans displayed markedly superior dose conformity. While SEQ-VMAT displayed favorable organ sparing for femoral heads, SIB-VMAT appeared as the more efficient approach for mitigating bladder and bowel doses. TCP was significantly higher with SIB-VMAT, suggesting a higher likelihood of successful tumour control. Conversely, no statistically significant difference in NTCP was observed between the two techniques. This study’s findings underscore the advantages of SIB-VMAT over SEQ-VMAT in terms of improved target coverage, dose conformity, and tumour control probability. In particular, SIB-VMAT demonstrated potential benefits for cases involving para-aortic nodes. It is concluded that SIB-VMAT should be the preferred approach in all cases of locally advanced cervical cancer. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024.
Covalent immobilization of Β-amylase onto functionalized molybdenum sulfide nanosheets, its kinetics and stability studies: A gateway to boost enzyme application
(Elsevier B.V., 2017) Ranjana Das; Himanshu Mishra; Anchal Srivastava; Arvind M. Kayastha
Present study reports the utilization of molybdenum sulfide nanosheets (MoS2-NSs) as a novel platform for β-amylase immobilization via glutaraldehyde activation, producing nanobiocatalyst with exotic superiority over the independent enzyme. Confocal microscopy, Fourier transform infrared (FT-IR) spectroscopy, Scanning electron microscopy (SEM) and Atomic force microscopy (AFM) studies demonstrated successful immobilization of β-amylase onto MoS2-NSs. Optimizing parameters by Box-Behnken design of Response Surface Methodology, approximately 92% immobilization efficiency was achieved. Thermo-stability, pH stability, reusability and storage stability of immobilized β-amylase were interestingly superior with respect to the soluble enzyme. β-Amylase immobilized onto MoS2-NSs exhibited maximum catalytic activity at the same pH and temperature as the soluble enzyme but with broadening in the range of parameters. In addition, the immobilized enzyme retained almost 80% residual activity, even after 10 reuses. Immobilized enzyme had around 83% residual activity upon storage over a period of 50 days. Changes in Michaelis-Menten constant after immobilization, point that some of the active sites of enzyme were inaccessible to substrate due to strained enzyme structure upon immobilization. The results obtained here suggest that the β-amylase-MoS2-NSs system could be used in industrial processes permitting broader temperature and pH ranges. Besides, the non-toxic nature of matrix, long-term storage and reusability of nanobiocatalyst could be magnificently used for the production of maltose in food and pharmaceutical industries. © 2017 Elsevier B.V.
Enhanced Osteogenesis by Molybdenum Disulfide Nanosheet Reinforced Hydroxyapatite Nanocomposite Scaffolds
(American Chemical Society, 2019) Umakant Yadav; Himanshu Mishra; Vimal Singh; Sunayana Kashyap; Anchal Srivastava; Sanjay Yadav; Preeti S. Saxena
The advances in the arena of biomedical engineering enable us to fabricate novel biomaterials that provide a suitable platform for rapid bone regeneration. Herein, we have investigated the in vitro and in vivo osteogenic differentiation, proliferation, and bone regeneration capability of molybdenum disulfide nanosheets (MoS2NSs) reinforced HAP nanocomposite scaffolds. The MG-63 cells were incubated with HAP and HAP/MoS2NSs nanocomposite and followed for various cellular activities. The cells incubated with HAP@2 shows higher cell adhesion, cell proliferation, and alkaline phosphatase activity (ALP) in contrast to HAP. The in vivo and in vitro results of the increased ALP level confirm that HAP@2 promotes osteogenic differentiation. This improved osteogenesis was validated with upregulation of osteogenic marker viz. transcription factor, RUNX-2 (∼34 fold), collagen-1 (∼15 fold), osteopontin (∼11 fold), osteocalcin (∼20 fold), and bone morphogenetic protein-2 (∼12 fold) after 12 week postimplantation in comparison to drilled. The X-ray imaging demonstrates that HAP@2 implants promote rapid osteogenesis and bioresorbability than HAP and drilled. The outcomes of the present study provide a promising tool for the regeneration of bone deformities, without using any external growth factor. © 2019 American Chemical Society.
Enhancing Fricke Xylenol Gel Dosimeter’s Response to Radiation with Optimized Preparation Methods
(Mashhad University of Medical Sciences, 2025) Shajid Syed Mohamed; Abhijit Mandal; K. Mondal; Gogul Priean V; Bratindranath Mukherjee; Praveen Chandra Pandey; Himanshu Mishra; Ritusha Mishra; Ganeshkumar Patel; Ankur Mourya; Lalit Mohan Mohan Aggarwal; Sunil Choudhary
Introduction: The fundamental principle of the Fricke gel dosimeter involves the oxidation of ferric ions upon exposure to radiation. However, a significant limitation of this dosimeter is the post-irradiation diffusion of ferric ions, which can result in the degradation of spatial dose information. Material and Methods: Gels were prepared using 300 bloom gelatin, deionized water, sulfuric acid, ferrous ammonium sulfate, and xylenol orange dye (Sigma-Aldrich). The solution was then poured into 10 ml plastic cuvettes. The gel samples were refrigerated at various temperatures for 1 to 10 days and irradiated within a water bath environment utilizing a telecobalt unit (Phoenix, Theratronics) employing parallel opposed beams. Spectrophotometric analysis at a wavelength of 585 nm was used to measured optical density changes with dose. This procedure was repeated across gel formulations prepared under differing pH conditions. Results: The gel’s optimum pH value, which was stored for 10 days at 5° C, showed a linear response up to 10 Gy, although the storage time was longer than that of the gels with low (0.3) and high pH (1.3). The auto oxidation rate was determined and found to be less for non-irradiated gel batches stored at 5° C in relation to the gel samples at room temperature and freezing temperature. Conclusion: The dose response of the dosimeter is highly dependent on its pH, composition, alkaline residuals, and pre-irradiation storing conditions. We observed the optimum pH is 1, at which the dosimeter shows a maximum response. Storing gel samples at 5°C notably reduces the Fe2+ to Fe3+ auto-oxidation rate. © (2025), (Mashhad University of Medical Sciences). All rights reserved.
Eu:Y2O3 highly dispersed fluorescent PVA film as turn off luminescent probe for enzyme free detection of H2O2
(Elsevier B.V., 2017) Dhananjay Kumar; Sima Umrao; Himanshu Mishra; Rohit Ranjan Srivastava; Monika Srivastava; Anchal Srivastava; S.K. Srivastava
In this work, a novel sensing scaffold consisting highly dispersed Eu:Y2O3 fluorescent flexible film of poly vinyl alcohol (EYCP) was synthesized by simple mixing method and applied to facilitate non-enzymatic detection of hydrogen peroxide (H2O2) by turn off probe of fluorescence. The fluorescence spectra of EYCP consisting number of emission sharp transitions from excited, 5D0→7Fj (j = 0, 1, 2, 3, 4) energy levels of doped Eu3+ ion in Y2O3 host. In the presence of H2O2, the fluorescence intensity of the EYCP film was quenched due to the reduction of electron–hole pair recombination in Eu centers by electron transfer from Eu–O excited state to H2O2 energy level rather than 5D0 state of Eu3+, which reduces the number of electron in 5D0 state. The EYCP film shows excellent fluorescence quenching in presence of H2O2 by significantly increasing concentration of H2O2 and completely quenched at ∼150 μM. A linear relationship is observed between 0.0 and 60 μM with a correlation coefficient of 0.989. H2O2 sensing is also compared with the EYC nanoparticles. This study is expected to have a significant impact on further study of the Eu:Y2O3 fluorescent flexible film for wide range applications. © 2017 Elsevier B.V.
Evaluation of survival outcome and prognostic factors for oral cavity cancer treated with volumetric arc therapy
(Springer Science and Business Media Deutschland GmbH, 2023) Himanshu Mishra; Shreya Singh; Ritusha Mishra; Ankita Pandey; Abhijit Mandal; Ekta Prakash; Ganeshkumar Patel; Manav Shah; Tej Bali Singh
Purpose: This study aimed to evaluate the survival outcomes and identify prognostic factors for patients with oral cavity cancer (OCC) who underwent adjuvant treatment with volumetric arc therapy (VMAT) using simultaneous integrated boost (SIB). Methods: Data was collected for post-operated patients of carcinoma of oral cavity who received adjuvant VMAT with SIB between June 2018 and December 2022. The data was entered and analyzed using SPSS software version 20.0. Survival rates were estimated using Kaplan Meier method. To determine survival difference between the groups, log rank test was used. Multivariate analyses were performed with Cox proportional hazard model and p value < 0.05 was considered as significant. Results: A total of 178 patients were included in the study. The median follow-up period was 26 months (range 3–56 months). The 3-year OS, DFS, and LRC rates were 78% (95% CI 77–79%), 76% (95% CI 74–77%), and 81% (95% CI 80–82%), respectively. Univariate analysis identified age ≥ 50 years, lymph node involvement, extracapsular extension (ECE), and N2–N3 disease as significant adverse prognostic factors for OS, DFS, and LRC. Multivariate analysis confirmed age ≥ 50 years and nodal involvement as independent predictors of worse OS, DFS, and LRC. Additionally, ECE independently affected OS and DFS. Conclusion: Adjuvant treatment with VMAT using SIBin patients with OCC is effective. Age and nodal involvement had significant impact on LRC, DFSand OS while ECE on DFSand OS. © 2023, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
Evaluation of survival outcomes and prognostic factors of carcinoma anal canal at a tertiary cancer center
(Wolters Kluwer Medknow Publications, 2023) Himanshu Mishra; Ritusha Mishra; Ankita Singh; Abhijit Mandal; Tej B. Singh; Anupam K. Asthana
Context: Concurrent chemoradiotherapy is considered a standard of care for patients with carcinoma anal canal. Being an unusual malignancy, there is limited Indian data regarding survival outcomes and prognostic factors. Aim: To evaluate survival outcomes and associated prognostic factors in patients with carcinoma anal canal treated with radical intent. Methods and Material: Patients with squamous cell carcinoma of the anal canal, treated with radical intent between 2015 and 2019 were included in the study. Data regarding the baseline characteristics of the patients and treatment outcomes were collected and analyzed. Survival rates were estimated using Kaplan-Meier method. To determine survival difference between the groups, log-rank test was used. Multivariate analyses were performed with Cox proportional hazard models and P value < 0.05 was considered significant. Results: Forty-two patients were identified after applying suitable eligibility criteria. The median age was 55 years (range: 26-80 years).The median follow-up duration was 23.5 months (range: 1.9-51.9 months). The 3-year overall survival (OS), disease-free survival (DFS), and locoregional (LRC) were 78.5%, 53.1%, and 66.4%, respectively. On multivariate analysis, inferior DFS was significantly affected by lack of concurrent chemotherapy (CT) (hazard ratio [HR], 11.50; 95% confidence interval [CI], 1.92-68.78; P = 0.007) and radiotherapy (RT) dose of 45 Gy or less (HR, 35.96; 95% CI, 6.32-204.56; P = 0.000). Conclusion: For patients of carcinoma anal canal, concurrent CT and RT dose are independent prognostic factors influencing DFS. © 2023 Copyright:
Fluorescence quenching of molybdenum disulfide quantum dots for metal ion sensing
(Springer, 2020) Himanshu Mishra; Vijay K. Singh; Rashid Ali; K. Vikram; Jai Singh; Arvind Misra; Hirdyesh Mishra; Anchal Srivastava
Abstract: In the present work, we have used hydrothermally synthesized in situ functionalized MoS2-QDs for a sensitive (limit of detection ~ 2.06 µM) and selective detection of Fe3+ ions. A detailed study of fluorescence quenching behavior for MoS2-QDs in the presence of Fe3+ ions has been performed using the Stern–Volmer plot, modified Stern–Volmer plot, and time-resolved photoluminescence measurements. Absorption based titration spectra and time-resolved photoluminescence measurements confirmed the fluorescence quenching is static with three decay times originated from the three different fluorescing sites. Interestingly, it is found that emission spectra consist of three bands at positions ~ 450 nm (P1, ~ 2.76 eV), ~ 475 nm (P2, ~ 2.61 eV), and ~ 503 nm (P3, ~ 2.46 eV). These peaks show a systematic quenching with the increasing concentration of Fe3+ ions. Quenching constants corresponding to these emission bands are found of the order of ~ 103 M−1. Large values of bimolecular quenching constants (~ 1011 M−1 s−1) suggest a strong binding interaction between MoS2-QDs and Fe3+ ions. Furthermore, to understand the fluorescence quenching of MoS2-QDs in the presence of Fe3+ ions, a ground-state complex formation-based mechanism has been proposed and elucidated in detail. Graphic abstract: [Figure not available: see fulltext.]. © 2020, Springer-Verlag GmbH Austria, part of Springer Nature.
Hiccups: An atypical side effect experienced during chemo-radiotherapy in carcinoma nasopharynx
(Wolters Kluwer Medknow Publications, 2023) Ankita Pandey; Himanshu Mishra; Pramod Kumar Singh; Ritusha Mishra
Nasopharyngeal carcinoma is an uncommon cancer but has a distinct racial and geographic distribution. Patient presents with constellation of signs and symptoms due to its vicinity to critical structures and are best treated by conformal concurrent chemo-radiotherapy. We present a case of 45-year-old male diagnosed with carcinoma nasopharynx, referred to us for radiotherapy after three cycles of neoadjuvant chemotherapy. As per the prevailing standard of care, patient was planned for radiotherapy by volumetric arc technique with concurrent cisplatin. Initial days of treatment were uneventful. After fourth week of treatment, patient developed persistent hiccup which was not relieved on conservative medications. Plan was re-evaluated and it revealed maximum dose of 54.6 Gy to the brainstem. Radiotherapy induced edema that could have stimulated vagus nerve leading to hiccups was suspected. Patient was started on injectable steroid and chlorpromazine. There was prompt recovery from the symptom within five days of conservative treatment. Copyright © 2023 Journal of Cancer Research and Therapeutics.
Highly stable and bio-compatible luminescent molybdenum disulfide quantum dots for imaging of alimentary canal in Drosophila
(Elsevier B.V., 2018) Himanshu Mishra; Sandeep Kumar Singh; Vijay K. Singh; Jai Singh; S. Srikrishna; Anchal Srivastava
Investigations on inorganic luminescent nanomaterials have always gained enormous attention of the science community for their possible applications in the fields of bioimaging and biomedicine. In this succession, various 0D structures including CdSe, CdTe, ZnS, graphene quantum dots (GQDs), carbon nanodots (CNDs) etc. have been explored for their possible applications in the field of biology. Recently, molybdenum disulfide quantum dots (MoS2-QDs) have been explored as an alternative of graphene quantum dots (GQDs) for their possible applications in relevant fields. Herein we report a facile, eco-friendly and single step hydrothermal synthesis of in-situ functionalized molybdenum disulfide quantum dots (f-MoS2-QDs). During the synthesis, variation in the pH of the starting solution provided the controlling over particle size. These as synthesized f-MoS2-QDs have shown excitation dependent broad emission spectra, which could be fitted for a parabolic function. The broadening in the emission spectra might be attributed to the polydispersity of f-MoS2-QDs in colloidal suspension, which was further confirmed with time resolved photoluminescence (TRPL) measurement. Due to surface capping provided by various functional groups present in the colloidal suspension, f-MoS2-QDs have shown excellent stability in aqueous medium and only a 3% of decrement in PL intensity was recorded even after six months. These synthesized f-MoS2-QDs possessed a quantum yield (QY) of 2.3% in aqueous media. Due to their high photostability and biocompatibility, these f-MoS2-QDs have been revealed as a potential entrant for in vivo bioimaging in Drosophila. © 2018 Elsevier B.V.
In Situ Functionalized Fluorescent WS2-QDs as Sensitive and Selective Probe for Fe3+ and a Detailed Study of Its Fluorescence Quenching
(American Chemical Society, 2019) Vijay K. Singh; Himanshu Mishra; Rashid Ali; Sima Umrao; Rajesh Srivastava; Shiju Abraham; Arvind Misra; Vidya Nand Singh; Hirdyesh Mishra; R.S. Tiwari; Anchal Srivastava
Most of the reports suggest that liquid exfoliated WS2-QDs are unstable; therefore the need of present day is to develop a novel synthesis route for producing long-term stable WS2-QDs. Herein, we report a bottom-up single-step hydrothermal growth of in situ functionalized blue fluorescent WS2-QDs with stable fluorescence in aqueous media without subsequent treatments. Presence of various functional groups over the surface of f-WS2-QDs provides high solubility and stability to f-WS2-QDs in aqueous media preserving its fluorescence. Further, photoluminescence property of f-WS2-QDs has been employed to devise an optical sensor with a high sensitivity (KD ∼104 M-1) and selectivity for ferric (Fe3+) ions. Under the optimal condition, response of the sensor is found to be linear in the range of 0-55 μM with a limit of detection (LOD) of 1.32 μM, which is within the maximum permissible level of Fe3+ (∼5.4 μM) in human drinking water by the USEPA. Further, we have also carried out a detailed evaluation on fluorescence quenching kinetics of f-WS2-QDs. Nonlinear behavior of S-V plot and TRPL measurements suggest that quenching is a mixed phenomenon of dynamic as well as static processes. Finally we have proposed a mechanism for fluorescence quenching of f-WS2-QDs in the presence of Fe3+ © 2018 American Chemical Society.
Microwave-assisted boron and nitrogen co-doped reduced graphene oxide as a transparent conductive electrode
(American Institute of Physics Inc., 2017) Sima Umrao; Himanshu Mishra; Anchal Srivastava; Sungjoo Lee
A crystalline Boron (B)- and Nitrogen (N)-co-doped microwave-assisted reduced graphene oxide (BNMRGO) film was investigated as a potential transparent conducting electrode (TCE) material. X-ray diffraction results revealed the good crystallinity of the BNMRGO film, and the presence of a (0004) reflection plane indicated the formation of a few small domains of hexagonal boron nitride in the microwave assisted reduced graphene oxide (MRGO) sheets under the co-doping process. Raman and X-ray photoelectron spectroscopic results indicated a reduction of sp3 carbon centers upon co-doping. The ID/IG ratio decreased after co-doping from 0.89 to 0.24, indicating a low average defect density of ∼1.01 × 1010 cm-2. Optoelectronic characterization of the BNMRGO film on a glass substrate revealed a high optical transparency of 82% at 550 nm and a low sheet resistance (Rsh) of 355 Ω/sq, which was lower than that observed from the MRGO sheets (Rsh = 719 Ω/sq). BNMRGO provided a ratio between the direct conductivity (σdc) to the optical conductivity (σoc), that is, the figure of merit of a TCE material, of 5.96. Overall, this work paves the way toward developing a manufacturable TCE. © 2017 Author(s).