366 research outputs found
Implementation of High Security Cryptographic System with Improved Error Correction and Detection Rate using FPGA
In this article, an encryption algorithm with an error detection technique is presented for highly secured reliable data transmission over unreliable communication channels. In this algorithm, an input data is mapped into orthogonal code first. After that the code is encrypted with the help of Linear Feedback Shift Register (LFSR). The technique has been successfully verified and synthesized using Xilinx by Spartan-3E FPGA. The results show that the error detection rate has been increased to 100% by proposed encryption scheme is effective and improves bandwidth efficiency
EFFICIENCY AND RADIATIVE RECOMBINATION RATE ENHANCEMENT IN GAN/ALGAN MULTI-QUANTUM WELL-BASED ELECTRON BLOCKING LAYER FREE UV-LED FOR IMPROVED LUMINESCENCE
In this paper, an electron blocking layer (EBL) free GaN/AlGaN light emitting diode (LED) is designed using Atlas TCAD with graded composition in the quantum barriers of the active region. The device has a GaN buffer layer incorporated in a c-plane for better carrier transportation and low efficiency droop. The proposed LED has quantum barriers with aluminium composition graded from 20% to ~2% per triangular, whereas the conventional has square barriers. The resulted structures exhibit significantly reduced electron leakage and improved hole injection into the active region, thus generating higher radiative recombination. The simulation outcomes exhibit the highest internal quantum efficiency (IQE) (48.4%) indicating a significant rise compared to the conventional LED. The designed EBL free LED with graded quantum barrier structure acquires substantially minimized efficiency droop of ~7.72% at 60 mA. Our study shows that the proposed structure has improved radiative recombination by ~136.7%, reduced electron leakage, and enhanced optical power by ~8.084% at 60 mA injected current as compared to conventional GaN/AlGaN EBL LED structure
Arsenic Induced Toxicity in Broiler Chicks and Its Amelioration with Ascorbic Acid: Clinical, Hematological and Pathological Study
This study was conducted to observe the arsenic (As) toxicity lesions in birds and to know either Vit C ameliorates these toxic effects or not. One-day-old broilers chicks (n=72) procured from a local hatchery were randomly divided into four equal groups. First group was kept as control and second group was given As (50 mg/kg BW) via crop tubing. Third group received in addition to As, Vit C (250 mg/kg BW) whereas fourth group received only Vit C. Killing by neck dislocation of randomly selected six birds from each group was carried out on experimental days 0, 16 and 32 for collection of blood and tissues specimens. Arsenic treated birds showed clinical signs of toxicity throughout the experiment than all other groups. These clinical signs included decreased body weight and feed intake, dullness, open mouth breathing, increased thirst, ruffled feathers, pale comb, skin irritation and watery diarrhea which were not significant in any other group. As treated group showed a significant (P<0.05) decrease in hematological parameters. Severe gross and histopathological changes were observed in intestines, spleen and lungs of birds fed with As than all other groups. Decreased height of villi of middle portion of small intestines was also observed in As treated birds. Villi height in Vit C treated group increased as compared to control group. It was concluded that As induces severe toxic effects in broiler birds; however, these toxic effects can be partially ameliorated by Vit C
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The material properties of naked mole-rat hyaluronan.
Hyaluronan (HA) is a key component of the extracellular matrix. Given the fundamental role of HA in the cancer resistance of the naked mole-rat (NMR), we undertook to explore the structural and soft matter properties of this species-specific variant, a necessary step for its development as a biomaterial. We examined HA extracted from NMR brain, lung, and skin, as well as that isolated from the medium of immortalised cells. In common with mouse HA, NMR HA forms a range of assemblies corresponding to a wide distribution of molecular weights. However, unique to the NMR, are highly folded structures, whose characteristic morphology is dependent on the tissue type. Skin HA forms tightly packed assemblies that have spring-like mechanical properties in addition to a strong affinity for water. Brain HA forms three dimensional folded structures similar to the macroscopic appearance of the gyri and sulci of the human brain. Lung HA forms an impenetrable mesh of interwoven folds in a morphology that can only be described as resembling a snowman. Unlike HA that is commercially available, NMR HA readily forms robust gels without the need for chemical cross-linking. NMR HA gels sharply transition from viscoelastic to elastic like properties upon dehydration or repeated loading. In addition, NMR HA can form ordered thin films with an underlying semi-crystalline structure. Given the role of HA in maintaining hydration in the skin it is plausible that the folded structures contribute to both the elasticity and youthfulness of NMR skin. It is also possible that such densely folded materials could present a considerable barrier to cell invasion throughout the tissues, a useful characteristic for a biomaterial.This work was supported by a Cancer Research UK/RCUK Multidisciplinary Project Award (C56829/A22053) to K.R., E.S. and D.F. and a Cancer Research UK Career Establishment Award (C47525/A17348) to W.T.K. F.H. and S.C. were supported by Gates Cambridge Trust scholarships
Castor Leaves-Based Biochar for Adsorption of Safranin from Textile Wastewater
The prospect of synthesizing biochar from agricultural wastes or by-products to utilize them as a promising adsorbent material is increasingly gaining attention. This research work focuses on synthesizing biochar from castor biomass (CBM) and evaluating its potential as an adsorbent material. Castor biomass-based biochar (CBCs) prepared by the slow pyrolysis process at different temperatures (CBC400 °C, CBC500 °C, and CBC600 °C for 1 h) was investigated for the adsorption of textile dye effluents (safranin). The pyrolysis temperature played a key role in enhancing the morphology, and the crystallinity of the biochar which are beneficial for the uptake of safranin. The CBC600 adsorbent showed a higher safranin dye removal (99.60%) and adsorption capacity (4.98 mg/g) than CBC500 (90.50% and 4.52 mg/g), CBC400 (83.90% and 4.20 mg/g), and castor biomass (CBM) (64.40% and 3.22 mg/g). Adsorption data fitted better to the Langmuir isotherm model than to the Freundlich isotherm model. The kinetics of the adsorption process was described well using the pseudo-second-order kinetic model. The study on the effect of the contact time for the adsorption process indicated that for CBC600, 80% dye removal occurred in the first 15 min of the contact time. After three regeneration cycles, CBC600 exhibited the highest dye removal efficiency (64.10%), highlighting the enhanced reusability of CBCs. The crystalline patterns, functional binding sites, and surface areas of the prepared CBCs (CBC400, CBC500, CBC600) were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and Brunauer–Emmett–Teller surface area measurements, respectively
A comprehensive assessment of laser welding of biomedical devices and implant materials: recent research, development and applications
This review comprehensively covers the research accomplished in the field of laser welding of biomedical devices and implant materials. Laser welding technology in the recent past has been envisaged for numerous biomedical applications encompassing the reconstruction, fabrication, joining and sealing of the implanted biomaterials. It is the most studied and an increasingly applied manufacturing technology that garners the distinct advantages of smaller beam diameters leading to minimal thermal cycles that reduce the size of heat affected zone and instigate microstructural refinement. This paper presents a detailed critical review of similar and dissimilar welding of titanium alloys, cobalt-chromium alloys, steel, bulk metallic glasses and polymer-based biomaterials. Mechanical properties of the welded joints such as fatigue load, tensile and flexural strength, elongation, hardness and modulus of elasticity are discussed. The effect of laser processing parameters on microstructural features and the corresponding metallurgical defects encountered such as cracks, porosities, voids or the loss of alloying elements are reviewed. Furthermore, the corrosion behavior, cytotoxicity and biocompatibility of the welded implants in the simulated mediums are discussed. Furthermore, this article also summarizes the present-day applications associated with implant materials and is aimed at the further involvement of the laser precision technology in producing materials and joints with desired biomechanical characteristics. Lastly, the current research gaps on the role of laser welding of implants and the anticipated emerging fronts are summarized
Physical activity, smoking, and genetic predisposition to obesity in people from Pakistan:the PROMIS study
Background: Multiple genetic variants have been reliably associated with obesity-related traits in Europeans, but little is known about their associations and interactions with lifestyle factors in South Asians. Methods: In 16,157 Pakistani adults (8232 controls; 7925 diagnosed with myocardial infarction [MI]) enrolled in the PROMIS Study, we tested whether: a) BMI-associated loci, individually or in aggregate (as a genetic risk score - GRS), are associated with BMI; b) physical activity and smoking modify the association of these loci with BMI. Analyses were adjusted for age, age(2), sex, MI (yes/no), and population substructure. Results: Of 95 SNPs studied here, 73 showed directionally consistent effects on BMI as reported in Europeans. Each additional BMI-raising allele of the GRS was associated with 0.04 (SE = 0.01) kg/m(2) higher BMI (P = 4.5 x 10(-14)). We observed nominal evidence of interactions of CLIP1 rs11583200 (P-interaction = 0.014), CADM2 rs13078960 (P-interaction = 0.037) and GALNT10 rs7715256 (P-interaction = 0.048) with physical activity, and PTBP2 rs11165643 (P-interaction = 0.045), HIP1 rs1167827 (P-interaction = 0.015), C6orf106 rs205262 (P-interaction = 0.032) and GRID1 rs7899106 (P-interaction = 0.043) with smoking on BMI. Conclusions: Most BMI-associated loci have directionally consistent effects on BMI in Pakistanis and Europeans. There were suggestive interactions of established BMI-related SNPs with smoking or physical activity
C9orf72-derived arginine-containing dipeptide repeats associate with axonal transport machinery and impede microtubule-based motility
A hexanucleotide repeat expansion in the C9orf72 gene is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). How this mutation leads to these neurodegenerative diseases remains unclear. Here, we show using patient stem cell-derived motor neurons that the repeat expansion impairs microtubule-based transport, a process critical for neuronal survival. Cargo transport defects are recapitulated by treating neurons from healthy individuals with proline-arginine and glycine-arginine dipeptide repeats (DPRs) produced from the repeat expansion. Both arginine-rich DPRs similarly inhibit axonal trafficking in adult Drosophila neurons in vivo. Physical interaction studies demonstrate that arginine-rich DPRs associate with motor complexes and the unstructured tubulin tails of microtubules. Single-molecule imaging reveals that microtubule-bound arginine-rich DPRs directly impede translocation of purified dynein and kinesin-1 motor complexes. Collectively, our study implicates inhibitory interactions of arginine-rich DPRs with axonal transport machinery in C9orf72-associated ALS/FTD and thereby points to potential therapeutic strategies.</p
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