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Highly secured authentication and fast handover scheme for mobility management in 5G vehicular networks
The Fifth Generation (5 G) networks exhibit high flexibility and diversity in their design and deployment strategies. Transitions between base stations (BSs), heterogeneous networks (HetNets) and other cellular networks provide significant vulnerabilities and expose users to substantial risks associated with cybersecurity attacks. This article evaluates current handover authentication methods in the context of 5 G networks while proposing a set of security criteria for handover authentication. This study presents a novel authentication technique called SHK (Secure Handover Key) that utilizes SDNs (Software Defined networks). The proposed scheme integrates recycled lightweight dynamic key cryptography and combines security features such as perfect forward secrecy and robustness to leakages. The significance of the proposed approach is assessed in terms of computations, communications, signals, and energy costs on 5 G mobility applications and Vehicular Communication Networks (VCNs). The scheme employed in this study demonstrates enhanced security measures and improved changeover performance compared to conventional schemes. 2024 Elsevier Ltd -
Highly mixed high-energy d-orbital states enhance oxygen evolution reactions in spinel catalysts
Design, synthesis, and engineering of electrocatalysts for the oxygen evolution reaction (OER) are essential for attaining desirable electrocatalytic performance towards practical implementation. Emerging spinel-type OER catalysts have not reached the desirable activity and durability, thus demanding critical research to advance the field. To achieve enhanced OER performance for spinel-type OER catalysts, we present an efficient strategy of electronic structure modulation of central metal atoms. Modulation of the electronic properties of the Zn and Co atoms through the counter anionic components (O, S, and Se) regulates the adsorption of oxygen intermediates and thus enhances OER activity, which is systematically demonstrated using Density Functional Theory (DFT) calculation. Although the zinc cobalt selenide catalyst showed the less pronounced trigonal distortion, the mixing of eg orbitals with selenium accounts for the experimentally observed enhancement in OER activity. The result is, in contrast to the benchmark catalyst made of RuO2, ZnCo2Se4@rGO demonstrated lower OER overpotential (?10 = 302 mV) and Tafel slope (58 mV dec?1) as well as greater durability at 10 mA cm?2 for 50 h. The implementation of this strategy in several spinel-type catalysts could improve their electrocatalytic performance. 2023 Elsevier B.V. -
Highly luminescent ZnS:Mn quantum dots capped with aloe vera extract
This study demonstrates the optical properties of ZnS:Mn2+ qquantum dots synthesized by simple and eco-friendly chemical precipitation method using aloe vera (AV) extract as the stabilizing agent. The nanoparticles have been characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, diffuse reflectance spectroscopy (DRS), photoluminescence (PL) and time-resolved PL spectroscopy. Increase in band gap energy with decrease in particle size was observed from DRS studies due to quantum confinement effect. Dominant yellow emission was observed from characteristic 4T1?6A1 transitions of the Mn2+ions in the ZnS:Mn/AV nanoparticles. The results provide insight to the quantum confinement effect that occur and how it affect decay life time of the ZnS:Mn2+/AV nanoparticles. 2020 Elsevier Ltd -
Highly Luminescent MOF and Its in Situ Fabricated Sustainable Corn Starch Gel Composite as a Fluoro-Switchable Reversible Sensor Triggered by Antibiotics and Oxo-Anions
Frequent use of antibiotics and the growth of industry lead to the pollution of several natural resources which is one of the major consequences for fatality to human health. Exploration of smart sensing materials is highly anticipated for ultrasensitive detection of those hazardous organics. The robust porous hydrogen bonded network encompassing a free-NH2 moiety, Zn(II)-based metal-organic framework (MOF) (1), is used for the selective detection of antibiotics and toxic oxo-anions at the ppb level. The framework is able to detect the electronically dissimilar antibiotic sulfadiazine and nitrofurazone via fluorescence "turn-on"and "turn-off"processes, respectively. The antibiotic-triggered reversible fluoro-switching phenomena (fluorescence "on-off-on") are also observed by using the fluorimetric method. An extensive theoretical investigation was performed to establish the fluoro-switching response of 1, triggered by a class of antibiotics and also the sensing of oxo-anions. This investigation reveals that the interchange of the HOMO-LUMO energy levels of fluorophore and analytes is responsible for such a fluoro-switchable sensing activity. Sensor 1 showed the versatile detection ability which is reflected by the detection of a carcinogenic nitro-group-containing drug "roxarsone". In view of the sustainable environment along with quick-responsive merit of 1, an in situ MOF gel composite (1@CS; CS = corn starch) is prepared using 1 and CS due to its useful potential features such as biocompatibility, toxicologically innocuous, good flexibility, and low commercial price. The MOF composite exhibited visual detection of the above analytes as well as antibiotic-triggered reversible fluoro-switchable colorimetric "on-off-on"response. Therefore, 1@CS represents a promising smart sensing material for monitoring of the antibiotics and oxo-anions, particularly appropriate for the real-field analysis of carcinogenic drug molecule "roxarsone"in food specimens. 2022 American Chemical Society. -
Highly Efficient Photocatalytic Conversion of Amine to Amide and Degradation of Methylene Blue Using BiOClTiO2 Nano Heterostructures
Abstract: Facile green synthesis of BiOClTiO2 was done using combustion technique by Ixora coccinea leaf extract as fuel source. The said material was characterized using XRD, SEM, EDX, HRTEM, SAED, FTIR, and UV-DRS. The particle size was found to be approximately 60nm and a crystallite size of 0.3nm from TEM. The photocatalytic activity of the material was found out using photoluminescence studies, dye degradation and photocatalytic organic conversion. The material showed excellent dye degradation capacity for methylene blue with 80% of the dye degraded under 3hrs. The stabilisation of electronhole pair by the heterostructure gave it the ability to perform easy degradation. The degradation kinetics have also been studied. It also showed an excellent organic conversion property with formylation yield reaching up to 96% and total conversion of the reactant molecule. The material is a potent photocatalyst due to its great efficiency and can have a remarkable role in the synthesis of important organic molecules and detoxification of environment. Graphical Abstract: The heterostructure catalyses the conversion of amine to amides and mineralizes methylene blue under visible light condition. [Figure not available: see fulltext.]. 2020, Springer Science+Business Media, LLC, part of Springer Nature. -
Higher education institutions as a catalyst for sustainability development
Growing concerns about the planet and society have led to the evolution of the concept of sustainable development. This concept gained popularity when the World Commission on Environment and Development released its report Our Common Future in 1987. In 1975, United Nations Educational, Scientific and Cultural Organization (UNESCO) brought sustainability as the International Environmental Education Program focusing on environmental education. This gave birth to the idea that Higher Educational Institutions (HEIs) can play a significant role in promoting the sustainability agenda. Over the years, this was done by implementing sustainability initiatives on the campus. These initiatives mostly focused on the environment and ignored the social and economic dimensions of sustainability. Given the paucity of adequate knowledge in this field, the chapter aims to explore the challenges in implementing sustainable initiatives and suggest a framework that will guide HEIs to act as a catalyst for sustainability development. 2024, IGI Global. All rights reserved. -
Higher Education in Maldives amidst the Pandemic: An Intersectional Approach to Digital Education
The Covid-19 outbreak upended the core foundations of societies across the globe, leading to dramatic shifts in knowledge, attitudes, and values. The education sector, known for its traditional classroom model, had to adapt quickly. However, the pandemic's impact varied widely due to social, cultural, economic, geographic, and gender factors. Amid such inequal pandemic disruptions, Maldives presents a unique case as an upper-middle-income economy with diverse higher education (HE) opportunities. The pandemic pushed Maldives towards digital education, capitalizing on pre-existing capabilities. The study employs an intersectional feminist approach to the gender digital divide, seeking to understand how the rapid adoption of digital education in Maldives' higher education institutions (HEIs) has unfolded during the pandemic. The analysis reveals deeply entrenched gender norms that have had a disproportionate impact on women students and lecturers in HEIs. Factors like unpaid domestic labour and care work, lack of suitable home space, absence of psychological support, and reinforcement of gender roles have primarily widened the gender digital divide in digital education during the pandemic. Moreover, local, social, and cultural attitudes further exacerbate this divide signifying a pressing need to re-evaluate women's roles in HEIs in the post-pandemic world. 2025 selection and editorial matter, Padma Rani, Bhanu Bhakta. -
High-Speed Parity Number Detection Algorithm inRNS Based onAkushsky Core Function
The Residue Number System is widely used in cryptography, digital signal processing, image processing systems and other areas where high-performance computation is required. One of the computationally expensive operations in the Residue Number System is the parity detection of a number. This paper presents a high-speed algorithm for parity detection of numbers in Residue Number System based on Akushsky core function. The proposed approach for parity detection reduces the average time by 20.39% compared to the algorithm based on the Chinese Remainder Theorem. The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024. -
High-performance reconfigurable FET for a simple variable gain buffer amplifier design
Design and simulation of variable gain analog buffer amplifier using single gate reconfigurable field-effect transistor (SG-RFET) with strained silicon channel are proposed. The design simplicity makes SG-RFET device a potential candidate compared to the multi-gate RFET devices. The gain of the proposed configuration is varied by tuning the feedback voltage. The voltage gain of the proposed configuration can be tuned from 0.97V/V to 5V/V with an output load of 1 k?. The operational transconductance amplifier (OTA) using the SG-RFET device is used in the proposed buffer amplifier design. 2021 Informa UK Limited, trading as Taylor & Francis Group. -
High-Performance ?-cyclodextrin-Ti3C2Tx MXene-Based Electrochemical Sensor for the Detection of Neurological Disorder Biomarker
In this work, the ?-cyclodextrin-MXene (?-CD-MXene) composite was employed as a modifier for carbon fiber paper (CFP) electrodes and quantification of L-methionine (L-Met). The ?-CD-MXene composite was prepared by hydrothermal synthesis route by adding ?-CD and Ti3C2Tx MXenes obtained via the Minimally intensive layer delamination technique. Cyclic voltammetry (CV) and Differential Pulse Voltammetry (DPV) were conducted to study the influence of scan rate and pH on the electrooxidation of L-Met studies using the ?-CD-MXene/CFP electrode. The layered structure of the exfoliated Ti3C2Tx MXenes with charge transfer efficiency in combination with the host-guest interaction ability of ?-CD enhances the electrooxidation of L-Met. The ?-CD-MXene/CFP electrode showcased high sensitivity, reproducibility, and stability, and the anodic peak currents were in linearity with L-Met concentration within the range of 0.09-540 ?M and LOD of 0.03 ?M under various optimized conditions. In addition, the developed sensor showcases highly selective and non-interfering sensing of L-Met. 2024 The Electrochemical Society (ECS). Published on behalf of ECS by IOP Publishing Limited. -
High-Movement Human Segmentation in Video Using Adaptive N-Frames Ensemble
A wide range of camera apps and online video conferencing services support the feature of changing the background in real-time for aesthetic, privacy, and security reasons. Numerous studies show that the Deep-Learning (DL) is a suitable option for human segmentation, and the ensemble of multiple DL-based segmentation models can improve the segmentation result. However, these approaches are not as effective when directly applied to the image segmentation in a video. This paper proposes an Adaptive N-Frames Ensemble (AFE) approach for high-movement human segmentation in a video using an ensemble of multiple DL models. In contrast to an ensemble, which executes multiple DL models simultaneously for every single video frame, the proposed AFE approach executes only a single DL model upon a current video frame. It combines the segmentation outputs of previous frames for the final segmentation output when the frame difference is less than a particular threshold. Our method employs the idea of the N-Frames Ensemble (NFE) method, which uses the ensemble of the image segmentation of a current video frame and previous video frames. However, NFE is not suitable for the segmentation of fast-moving objects in a video nor a video with low frame rates. The proposed AFE approach addresses the limitations of the NFE method. Our experiment uses three human segmentation models, namely Fully Convolutional Network (FCN), DeepLabv3, and Mediapipe. We evaluated our approach using 1711 videos of the TikTok50f dataset with a single-person view. The TikTok50f dataset is a reconstructed version of the publicly available TikTok dataset by cropping, resizing and dividing it into videos having 50 frames each. This paper compares the proposed AFE with single models and the Two-Models Ensemble, as well as the NFE models. The experiment results show that the proposed AFE is suitable for low-movement as well as high-movement human segmentation in a video. 2022 Tech Science Press. All rights reserved. -
High-affinity binding of celastrol to monomeric ?-synuclein mitigates invitro aggregation
?-Synuclein (?Syn) aggregation is associated with Parkinsons disease (PD). The region ?Syn36-42 acts as the nucleation 'master controller and ?Syn1-12 as a secondary nucleation site. They drive monomeric ?Syn to aggregation. Small molecules targeting these motifs are promising for disease-modifying therapy. Using computational techniques, we screened thirty phytochemicals for ?Syn binding. The top three compounds were experimentally validated for their binding affinity. Amongst them, celastrol showed high binding affinity. NMR analysis confirmed stable ?Syn-celastrol interactions involving several residues in the N-terminus and NAC regions but not in the C-terminal tail. Importantly, celastrol interacted extensively with the key motifs that drive ?Syn aggregation. Thioflavin-T assay indicated that celastrol reduced ?Syn aggregation. Thus, celastrol holds promise as a potent drug candidate for PD. Communicated by Ramaswamy H. Sarma. 2023 Informa UK Limited, trading as Taylor & Francis Group. -
High surface area Nanoflakes of P-gC3N4 photocatalyst loaded with Ag nanoparticle with intraplanar and interplanar charge separation for environmental remediation
The photocatalytic performance of gC3N4 is majorly restricted by insufficient collection of photogenerated charges on the surface during reaction due to highly dense stacking of lamellar structures with lateral size ranging in microns. This deficiency can be overcome by forming thin nanoflakes by systematically breaking the weak bonds that hold the gC3N4 framework without destroying the basic heptazine unit. With this aim, herein, a combination of three different strategies was implemented to design and develop, Ag-loaded and P-doped gC3N4 nanoflakes (Ag3-P1-NF-gC3N4). Using a systematic synthesis method, bulk gC3N4 was first converted into thin nanosheets, followed by fragmentation into nanoflakes, with a planar size up to 100 nm. P doping to replace the corner C atoms in the gC3N4 matrix (forming P[sbnd]N bonds) and intercalation of plasmonic Ag nanoparticles within the interlayers also assists in the bifurcation of the stacked layers and formation of nanoflake morphology. These strategies result in a significant increase in BET surface area to ?196 m2/g from 12 m2/g of bulk gC3N4. Improved inter-planar and intra-planar charge mobility was recorded as a result of the reduced sizes. Doping with P also causes higher absorption of the visible spectrum in gC3N4 while the formation of heterojunction with Ag nanoparticles induces efficient separation of photo-generated charges. All these promoting photo-physical properties lead to an outstanding photocatalytic activity towards degradation of aqueous pollutants with reaction rates ?20 times higher than bulk gC3N4. Complete mineralization of the pollutant and formation of non-toxic byproducts was also confirmed with suitable chromatography techniques. 2020 Elsevier B.V. -
High performance computational method for fractional model of solid tumour invasion
The behaviour of the solid tumour invasion system in the sense of Caputo fractional with time ? and space x is analyzed by the high performance computational method: q-Homotopy Analysis Transform method (q-HATM). The existence of the solutions has been verified with the assist of fixed point theorem and derived numerical solution for different values of ?,?,h. The novel simulation for all cases is explained through figures. We derived that the method is very efficient for analyzing the behaviour of the epidemiological system. 2023 THE AUTHORS -
High gain ultra wideband fractal antenna
A high gain Compact Octagonal Ultra-wideband Fractal Antenna (COUFA) using the Dual Layer Meta Frequency Selective Surface Reflector (DLMFSSR) is presented in this manuscript. The proposed Frequency Selective Surface (FSS) provides a suitable reflection phase to act as a reflector and is capable of enhancing the gain of the antenna in its wide operating bandwidth. The proposed antenna design provides better impedance bandwidth of 2-10.37 GHz with significant increase in the gain of 0.41-11.83 dB at various resonance frequencies in comparison with the antenna without reflector. The complete antenna with DLMFSSR is designed and simulated using High Frequency Structure Simulator (HFSS). The Proposed antenna, FSS are fabricated and the numerical results for return loss S11, VSWR and gain are demonstrated. Simulation and fabrication results are found to be worthy, which suites the design malleable enough for several modern UWB wireless applications. Copyright 2019 American Scientific Publishers All rights reserved. -
High Gain Miniature Antenna Arrays for 2.4 GHz Applications
In this paper, miniature corporate feed Four Element Array (FEA), Eight Element Array (EEA) and Sixteen Element Array (SEA) are presented. The proposed antenna arrays are created on Rogers Duroid 5880 substrate with permittivity 2.2 and thickness of 0.782 mm. Initially, a single element antenna was created, then it was used in a corporate feed network designed for the 4-element array. As an extension, the 4-element array was used as a template and created an 8-element array and 16-element array to achieve high gain and directivity at 2.4 GHz. The proposed FEA, EEA, and SEA exhibit reflection coefficients of -25.55 dB, -37.14 dB, and -30.61 dB respectively. The peak gains obtained are 11.5 dB, 13.67 dB, and 16.76 dB respectively for FEA, EEA, and SEA. Also, the directivity has improved corresponding to the increase in the number of elements. Therefore, it can be a suitable candidate for applicationswhere extended range and coverage with better signal quality and higher data transfer rates is a priority. 2024 IEEE. -
Hierarchically porous MN-MOFS composite with RGO as an efficient electrode material for supercapacitor application /
Patent Number: 202241046378, Applicant: Sruthi Rajasekaran.
The present invention shows the energy storage application of the manganese-reduced graphene oxide metal organic frameworks (Mn-rGO MOFs) using the ligand, pyridine 2,6 dicarboxylic acid (PDA), under mild conditions. The methodology followed was hydrothermai at 160°C with manganese sulfate as metal salt, rGO along with the PDA ligand in pyridine, and water as solvent. The development of efficient Mn-rGO MOFs is suitable for supercapacitance energy storage applications, which is the future need for various industrial applications. -
Hierarchically porous MN-MOFS composite with RGO as an efficient electrode material for supercapacitor application /
Patent Number: 202241046378, Applicant: Sruthi Rajasekaran.
The present invention shows the energy storage application of the manganese-reduced graphene oxide metal organic frameworks (Mn-rGO MOFs) using the ligand, pyridine 2,6 dicarboxylic acid (PDA), under mild conditions. The methodology followed was hydrothermai at 160°C with manganese sulfate as metal salt, rGO along with the PDA ligand in pyridine, and water as solvent. The development of efficient Mn-rGO MOFs is suitable for supercapacitance energy storage applications, which is the future need for various industrial applications. -
Hierarchically nanostructured ZnO with enhanced photocatalytic activity
Hierarchical nanostructures of ZnO are integrated architectures comprising well-ordered nanoscale subunits and excellent photocatalytic properties. In this study, synthesis of ZnO nanoparticles using methods such as co-precipitation, hydrothermal, thermal decomposition, and electrochemical precipitation yielded microsphere, nanorod, pyramid, and nanopetal-like morphologies, respectively. The catalysts obtained were characterized using XRD, IR, SEM-EDX, UVDRS, TGA, PL, and Zeta potential analysis. The XRD spectra confirmed that all the different morphologies of ZnO have hexagonal wurtzite structures The photocatalytic activity of these nanostructures was determined using a dye degradation study on a model pollutant Methylene Blue (MB) under simulated visible light. The kinetic study of the dye degradation reveals that it obeys pseudo-first-order kinetics with a maximum rate constant of 0.01503 min-1. The nanorod structured ZnO particles prepared by the hydrothermal method showed the best catalytic activity. 2021 The Electrochemical Society ("ECS"). Published on behalf of ECS by IOP Publishing Limited. -
Hierarchical porous covalent organic framework-based sensor for the detection of neurodegenerative disorder biomarkers
Guanosine is an essential biomarker that enacts an important role in neuroprotection against brain-related activities, influences the metabolism of fatty acids, and assists in the improvement of the gastrointestinal tract. A facile and selective electrochemical sensor has been developed for the sensing of guanosine based on a hierarchical porous covalent organic framework. Owing to the distinctive 2D porous architecture and ordered framework of TpBD-COF, the irreversible electrooxidation of guanosine occurred at 1.03 V (vs. SCE) in phosphate buffer solution at pH 6. The anodic peak currents under optimal conditions were linear with guanosine concentration within the range of 0.123720 ?M with a LOD of 40.63 nM under various optimal conditions. Moreover, the developed biosensor was used to determine guanosine in pharmaceutical tablets to confirm its potential application in the healthcare industry. 2023 Elsevier B.V.