Browsing by Author "Raghvendra Pratap"

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A comparative study of band gap engineered in-situ and ex-situ MWCNTs/TiO2 heterostructures for their enhanced photocatalytic activity under visible light
(Elsevier B.V., 2023) Anshu Kumar Singh; Pramod Kumar Vishwakarma; Sumit Kumar Pandey; Raghvendra Pratap; Rajiv Giri; Anchal Srivastava
Organic pollutants, such as various types of organic dyes coming out from the textile industries, are polluting surface and groundwater resources alarmingly and posing a threat to aquatic ecosystems. So, the demand for visible-light-driven high-performance photocatalysts having high activity and structural stability is a need of an hour. TiO2 has been one of the well-known and most studied semiconductor photocatalysts for decades. But its low electron-hole pair (e-/h+) recombination time reduces its efficiency, and the large band gap restricts its use as a visible-light-driven photocatalyst. To overcome these limitations of TiO2, herein, we have reported an in-situ and ex-situ MWCNTs modified TiO2 heterostructure nanocomposites photocatalyst and established a comparative study in terms of their ability to degrade methylene blue (MB) dye under visible light irradiation. The as-synthesized in-situ CNTs-TiO2 nanocomposite and ex-situ CNTs-TiO2 nanocomposite were characterized structurally, morphologically, compositionally, and optically through various characterization techniques such as XRD, RAMAN, SEM, XPS, FTIR, and UV–Vis diffuse reflectance spectroscopy. The result reveals the band gap tuning in the in-situ and ex-situ CNTS-TiO2 nanocomposites as a result of increasing MWCNTs concentration. The in-situ CNTs-TiO2-2 nanocomposite has high degradation efficiency (94% in 150 min) and stability due to smooth and strong chemical interactions between the MWCNTs and TiO2, while ex-situ CNTs-TiO2-20 with 10 times more MWCNTs concentration (by weight) as compared to MWCNTs concentration in in-situ CNTs-TiO2-2, exhibits degradation efficiency of 89% in 150 min. The possible degradation mechanism to degrade MB dye has also been put forward. © 2023
Catalyst-free biphasic orthorhombic/hexagonal tungsten oxide system with enhanced photocatalytic response under visible light
(Oxford University Press, 2023) Anshu Kumar Singh; Sumit Kumar Pandey; Pramod Kumar Vishwakarma; Raghvendra Pratap; Ranjana Verma; Anamika Pandey; Rajiv Giri; Anchal Srivastava
These days, textile industries pose a more significant threat to surface water and groundwater sources directly or indirectly by discharging wastewater containing various dyes and organic pollutants to these water sources. The phase-junction-engineered heterogeneous photocatalysis carried out by visible light-driven semiconductor photocatalysts is opening a new window for the degradation of environmental organic pollutants. In this work, we have reported a one-step bottom-up hydrothermal synthesis of biphasic tungsten oxide (o/h-WO3) and performed a photodegradation experiment under visible light irradiation for the efficient degradation of organic pollutants such as Methylene blue (MB) and Methyl violet (MV), respectively. The X-ray diffraction, RAMAN, transmission electron microscopy and ultraviolet-Vis characterization techniques were used to investigate the structural, morphological and optical properties of the as-synthesized o/h-WO3. Moreover, the low calculated band gap (∼2.8 eV) and the anionic nature of o/h-WO3 suggest it as an efficient visible light-driven photocatalyst suitable for heterogeneous photocatalysis. The photodegradation experiment performed under visible light using o/h-WO3 photocatalyst showed better degradation efficiency of 71% and 89% for MB and MV, respectively, in 100 min. The dyes followed first-order kinetics, and their kinetic rate constants were calculated using the Langmuir-Hinshelwood model. Furthermore, the recyclability study of the photocatalyst was also performed and discussed the underlying mechanism for the photodegradation of the organic dyes. © 2023 The Author(s).
Epidemiological features of aplastic anemia in Indian children
(Springer India, 2014) Vineeta Gupta; Raghvendra Pratap; Akash Kumar; Isha Saini; Jyoti Shukla
Objectives: To study the socio-demographic profile and clinico- hematological features of aplastic anemia in children presenting at a single institution over 5 y. Methods: Patients below the age of 15 y presenting with features of aplastic anemia were included in the study. Epidemiology, clinico-hematological features and treatment receivedwere recorded in all the cases. Serology for hepatitis A, B, C, E, EBV, parvovirus and HIV was carried out. Cytogenetic studies were available in approximately half of the patients. Results: One hundred eighty five patients were diagnosed with aplastic anemia. Ten patients with inherited bone marrow failure syndrome (IBMFS) were excluded. Median age was 8 y (range 4-14 y) with a male to female ratio of 2.4:1. Pallor (100%) followed by bleeding manifestations (83.8%) and fever (73.5%) were most common presenting symptoms. One hundred twenty patients (70%) were classified as severe, 36 (21%) very severe and 17 (9%) non-severe aplastic anemia. Viral markers for parvovirus, Epstein barr virus and hepatitis were positive in 25.8%, 20% and 6.7% patients respectively. Six patients had history of varicella infection in recent past (within 6 mo). Very few patients (30) could afford immunosuppressive therapy (IST) and had suboptimal response (29.7%). Conclusions: Majority of patients had idiopathic aplastic anemia. Very severe aplastic anemia and severe aplastic anemia were frequent. Few patients received IST and had suboptimal response. There is need to establish a national registry for aplastic anemia. © Dr. K C Chaudhuri Foundation 2013.
Investigations on structural, microstructural, dielectric and electrical conductivity of the ZnO-MWCNTs nanocomposite synthesized via sol-gel method
(Oxford University Press, 2025) Raghvendra Pratap; Anshu Kumar Singh; Sajal Rai; Atul Kumar Mishra; Jay Singh; Rajiv Giri; Anchal Srivastava
In our present work, we used cost effective sol-gel process to synthesize pure zinc oxide (ZnO-P), ZnO-MWCNTs nanocomposites with different MWCNTs concentrations: 5 wt.% (ZnO-5) and 10 wt.% (ZnO-10). The impact of varying concentration of MWCNTs on structural, microstructural and dielectric properties of ZnO-MWCNTs nanocomposites have been thoroughly examined. X-ray diffraction (XRD) analysis reveals that the ZnO-P possess a hexagonal wurtzite phase structure. As the concentration of MWCNTs in the ZnO increases, the peak broadening becomes more pronounced. In the Raman spectra of the ZnO nanorods, a sharp and intense peak was detected around 437 cm−1, corresponding to the high-frequency branch of the E2 mode of ZnO. ID/IG ratios for pure MWCNTs, ZnO-5 and ZnO-10 are 0.643, 0.723 and 0.840 respectively. TEM analysis shows nanorod-like structure of ZnO and SAED pattern of ZnO-MWCNTs nanocomposite confirms the structural integrity of nanocomposite material. Lattice- spacing of MWCNTs has been calculated 0.357 nm by IFFT image. The frequency dependence behaviour of the dielectric constant (ε'), dielectric loss factor (tan δ), and a.c. conductivity of ZnO-P, ZnO-5, and ZnO-10 has been measured. The dielectric properties of these samples possess behaviour consistent with the Maxwell-Wagner model and Koops phenomenological theory. The improvement in dielectric properties of ZnO-MWCNTs nanocomposites as compared to ZnO makes them a suitable candidate for energy storage applications. © 2025 The Author(s)
Neurological injury: Consequences and restorative and rehabilitation strategies
(Jenny Stanford Publishing, 2024) Sippy Singh; Hafsa Masood; Durgesh Singh; Atifa Hasee; Ansari; Raghvendra Pratap
The brain plays a crucial role in the coordination of bodily functions, and its different regions participate in controlling functions such as speech, cognition, memory, etc. The central nervous system (CNS) comprising the brain and spinal cord integrates at multiple levels for processing of multisensory information in regulating balance, posture, and mobility of an organism. These distributed controls of an organism are often affected by neuronal damage/injury. The loss of physiological and psychological functioning or structure is 358collectively known as impairments that limit the functional activities of a person and also restrict their social participation. Neurological injury mainly focuses on three categories or clinical pathways: single-incident brain and spinal cord damage and acute peripheral paralysis; alarming conditions such as degenerative dementia, Parkinson's disease, etc.; and conditions such as cerebral palsy and late effects of other single-incident events acquired in childhood. Such neurological injury imposes difficulties on the patients and the related family members in managing their daily chores and involvement in social gatherings. Single-incident brain injury may include stroke and traumatic brain injury (TBI). Stroke has been reported to be the most common cause of severe physical disablement in people living at home and is more prone with an advancing age. Symptoms related to neurological injury can cause distress and impact function. The need and line of treatment of patients suffering from neurological injury differ from patient to patient, and therefore, the treatment is successful only if individualized treatment goals are set and defined, which are relevant to the suffering patient. © 2024 by Jenny Stanford Publishing Pte. Ltd. All rights reserved.
Panchvalkal (an Ayurvedic Formulation) Proliferates Pancreatic β-Cells and Increases the Potency of Conventional drug Glibenclamide
(Springer, 2023) Ruchita Tripathi; Amit Ranjan; Raghvendra Pratap; Anil Kumar Singh; Rajesh Kumar Singh
Diabetes is a common metabolic syndrome in Indian population. The drugs used for its management based on enzyme and hormone. The development of resistance against conventional drugs in diabetic patients is a major challenge for clinicians to treat the patients effectively. Panchavalkala is a polyherbal formulation, described in Ayurveda for management of many clinical ailments and potentiating the antibacterial drugs in recent studies. In this study it has been evaluated for integration with conventional drug, Glibenclamide for potentiating the efficacy and safety for management of patient with diabetes mellitus in north Indian population. The methodology of Panchvalkala kwath preparation is according to protocol described in Ayurvedic Pharmacopoiea of India (API) and evaluated for safety and efficacy alone and integrated with conventional drug, Glibenclamide in in vitro as well as in-vivo model. The waster rats as used as in-vivo model with Streptozotocin diabetes induction. The results show that the integration of the Ayurvedic formulation is safe and potentiating the efficacy of Glibenclamide. © 2023, The Author(s), under exclusive licence to The National Academy of Sciences, India.