13 research outputs found

    Nano Layers of 2D Graphene Versus Graphene Oxides for Sensing Hydrogen Gas

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    Hydrogen is one of the most useful but dangerous gases because of its broad combustion range and small ignition temperature. Currently, there is a great need for hydrogen detectors with selectivity, high sensitivity and reliable operations in view of its safe production, storage, transportation and other applications. In this regard, nano thin films of two dimensional materials like graphene, graphene oxide (GO) and reduced graphene oxide (rGO) have immense promise because their material attributes can be exceptionally tuned to achieve the desired characteristics. Also graphene oxide and reduced graphene oxide serve as potential sensing hosts due to the presence of functional groups on their surfaces. In this chapter, an attempt has been made to compare the work done in the field of hydrogen sensors using pure graphene and graphene derivatives such as graphene oxide and reduced graphene oxide. The response parameters like sensitivity, stability, selectivity, response time, recovery time, detection limit, linearity, dynamic range, and working temperatures for various graphene based sensors have been elaborately compared. Finally, a conclusion and future outlook on nano scale thin film of graphene and graphene oxides for gas sensing have been briefly discussed

    How 'dynasty' became a modern global concept : intellectual histories of sovereignty and property

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    The modern concept of ‘dynasty’ is a politically-motivated modern intellectual invention. For many advocates of a strong sovereign nation-state across the nineteenth and early twentieth century, in France, Germany, and Japan, the concept helped in visualizing the nation-state as a primordial entity sealed by the continuity of birth and blood, indeed by the perpetuity of sovereignty. Hegel’s references to ‘dynasty’, read with Marx’s critique, further show how ‘dynasty’ encoded the intersection of sovereignty and big property, indeed the coming into self-consciousness of their mutual identification-in-difference in the age of capitalism. Imaginaries about ‘dynasty’ also connected national sovereignty with patriarchal authority. European colonialism helped globalize the concept in the non-European world; British India offers an exemplar of ensuing debates. The globalization of the abstraction of ‘dynasty’ was ultimately bound to the globalization of capitalist-colonial infrastructures of production, circulation, violence, and exploitation. Simultaneously, colonized actors, like Indian peasant/‘tribal’ populations, brought to play alternate precolonial Indian-origin concepts of collective regality, expressed through terms like ‘rajavamshi’ and ‘Kshatriya’. These concepts nourished new forms of democracy in modern India. Global intellectual histories can thus expand political thought today by provincializing and deconstructing Eurocentric political vocabularies and by recuperating subaltern models of collective and polyarchic power.PostprintPeer reviewe

    Prediction of positive cloud-to-ground lightning striking zones for tilted thundercloud based on line charge model

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    Bushfire is known as one of the ascendant factors to create pyrocumulus thundercloud that causes the ignition of new fires by pyrocumulonimbus (pyroCb) lightning strikes mostly of positive polarity, and causes massive damage to nature and infrastructure. A conceptual model-based risk planning would be beneficial to predict the lightning striking zones on the surface of the earth underneath the pyroCb thundercloud. In this paper, a simple line charge structured thundercloud model is constructed in 2-D coordinates using the method of images to predict the probable +CG (positive cloud-To-ground) lightning striking zones on the earth's surface for tilted dipole thundercloud charge configuration. The electric potential distribution and ground surface charge density for tilted dipole thundercloud is investigated via continuously adjusting the position and charge density of its charge regions. Simulation results confirm the initiation of negative charged density for the wind shear extension of upper positive charge region by 2 to 8 km, and would expect +CG lightning to strike within 7.88 to 20 km around the earth periphery particularly in the direction of the cloud's forward flank. The proposed model would serve as the foundation to identify the probable lightning affected area as well as can also be extended to analyze the hazardous situation appears in wind energy farms or agricultural fencing situated nearby the power grid during pyroCb events. © 2022 IEEE

    Fluorine Substituted Proline Enhances the Tubulin Binding Potential of a Tetrapeptide at the GTP Binding Pocket Causing the Inhibition of Microtubule Motility and an Antimitotic Effect

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    The microtubule is regarded as the key target for designing anticancer and neurotherapeutic drugs due to its functional importance in eukaryotic cells including neurons. The microtubule is a dynamic hollow polymer tube consisting of alpha,beta-tubulin heterodimer. Polymerization of alpha,beta-tubulin heterodimer resulted in microtubule formation. GTP plays a crucial role in microtubule polymerization. It binds at the exchangeable binding site of the beta-tubulin heterodimer, and it is one of the most crucial therapeutic hot spots for designing anticancer therapeutics. In this manuscript, we have shown using an in silico strategy and various in vitro and cellular experiments that the binding affinity to the tubulin and cancer therapeutic potential of an exchangeable GTP/GDP binding antimitotic tetrapeptide (SP: Ser-Leu-Arg-Pro) is increased through changing proline with the multifluorine substituted proline. This study showcases the importance of the proline amino acid and its pyrrolidine ring in the regulation of binding with tubulin at the GTP binding pocket

    Biodegradable Neuro-Compatible Peptide Hydrogel Promotes Neurite Outgrowth, Shows Significant Neuroprotection, and Delivers Anti-Alzheimer Drug

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    A novel neuro-compatible peptide-based hydrogel has been designed and developed, which contains microtubule stabilizing and neuroprotective short peptide. This hydrogel shows strong three-dimensional cross-linked fibrillary networks, which can capture water molecules. Interestingly, this hydrogel serves as excellent biocompatible soft material for 2D and 3D (neurosphere) neuron cell culture and provides stability of key cytoskeleton filaments such as microtubule and actin. Remarkably, it was observed that this hydrogel slowly enzymatically degrades and releases neuroprotective peptide, which promotes neurite outgrowth of neuron cell as well as exhibits excellent neuroprotection against anti-NGF-induced toxicity in neuron cells. Further, it can encapsulate antiAlzheimer and anticancer hydrophobic drug curcumin, releases slowly, and inhibits significantly the growth of a 3D spheroid of neuron cancer cells. Thus, this novel neuroprotective hydrogel can be used for both neuronal cell transplantation for repairing brain damage as well as a delivery vehicle for neuroprotective agents, anti-Alzheimer, and anticancer molecules

    α‑Cyclodextrin Interacts Close to Vinblastine Site of Tubulin and Delivers Curcumin Preferentially to the Tubulin Surface of Cancer Cell

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    Tubulin is the key cytoskeleton component, which plays a crucial role in eukaryotic cell division. Many anticancer drugs have been developed targeting the tubulin surface. Recently, it has been shown that few polyhydroxy carbohydrates perturb tubulin polymerization. Cyclodextrin (CD), a polyhydroxy carbohydrate, has been extensively used as the delivery vehicle for delivery of hydrophobic drugs to the cancer cell. However, interaction of CD with intracellular components has not been addressed before. In this Article, we have shown for the first time that α-CD interacts with tubulin close to the vinblastine site using molecular docking and Förster resonance energy transfer (FRET) experiment. In addition, we have shown that α-CD binds with intracellular tubulin/microtubule. It delivers a high amount of curcumin onto the cancer cell, which causes severe disruption of intracellular microtubules. Finally, we have shown that the inclusion complex of α-CD and curcumin (CCC) preferentially enters into the human lung cancer cell (A549) as compared to the normal lung fibroblast cell (WI38), causes apoptotic death, activates tumor suppressor protein (p53) and cyclin-dependent kinase inhibitor 1 (p21), and inhibits 3D spheroid growth of cancer cel

    Genesis of Neuroprotective Peptoid from Aβ30–34 Inhibits Aβ Aggregation and AChE Activity

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    Aβ peptide and hyper-phosphorylated microtubule associated protein (Tau) aggregation causes severe damage to both the neuron membrane and key signal processing microfilament (microtubule) in Alzheimer’s disease (AD) brains. To date, the key challenge is to develop nontoxic, proteolytically stable amyloid inhibitors, which can simultaneously target multiple pathways involved in AD. Various attempts have been made in this direction; however, clinical outcomes of those attempts have been reported to be poor. Thus, we choose development of peptoid (N-substituted glycine oligomers)-based leads as potential AD therapeutics, which are easy to synthesize, found to be proteolytically stable, and exhibit excellent bioavailability. In this paper, we have designed and synthesized a new short peptoid for amyloid inhibition from 30−34 hydrophobic pocket of amyloid beta (Aβ) peptide. The peptoid selectively binds with 17–21 hydrophobic region of Aβ and inhibits Aβ fibril formation. Various <i>in vitro</i> assays suggested that our AI peptoid binds with tubulin/microtubule and promotes its polymerization and stability. This peptoid also inhibits AChE-induced Aβ fibril formation and provides significant neuroprotection against toxicity generated by nerve growth factor (NGF) deprived neurons derived from rat adrenal pheochromocytoma (PC12) cell line. Moreover, this peptoid shows serum stability and is noncytotoxic to primary rat cortical neurons

    Nanoparticles for super-resolution microscopy: intracellular delivery and molecular targeting

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    Following an overview of the approaches and techniques used to acheive super-resolution microscopy, this review presents the advantages supplied by nanoparticle based probes for these applications. The various clases of nanoparticles that have been developed toward these goals are then critically described and these discussions are illustrated with a variety of examples from the recent literature
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