STUDY OF IMMOBILIZATION OF UREASE ON PVA-NANO NiFe2O4 NANOCOMPOSITE FOR BIOSENSOR APPLICATIONS

Objective: The main objective of this study to prepare the highly sensitive and high-performance biosensor using Nickel ferrite (NiFe2O4) nanoparticles and biological agent (enzyme) for the respective biosensor.Methods: Nickel ferrite (NiFe2O4) nanoparticles were prepared by using the sol-gel method. Prepared nanoparticles were dispersed in polyvinyl alcohol (PVA) solution in order to fabricate nanocomposite film on gold (Au) plate. Urease (Ur) has been immobilized onto this (PVA/NanoNiFe2O4/Au) nanocomposite film via physical adsorption method. The PVA/NanoNiFe2O4/Au electrode and Ur/PVA-nanoNiFe2O4/Au bio-electrode have been characterized using scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Synthesized nanoparticles were characterized by X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy.Results: The XRD of nanocrystalline NiFe2O4 showsspinel ferrites crystal structure and the average particle size of NiFe2O4 nanoparticles was found to be ~ 40 nm. The formation of NiFe2O4 was confirmed by FT-IR. The detecting performance of Nanocrystalline NiFe2O4 results in increased active surface area of PVA-nanoNiFe2O4/Au bioelectrode for immobilization of enzyme (Ur), enhanced electron transfer and increased shelf-life of bioelectrode. The Ur/PVA-nanoNiFe2O4/Au bioelectrode exhibits interesting characteristics such as detection range 5-50 mg/dl, response time as 2s with regression coefficient as 0.951. A Michalis-Menten constant (Km) as 2 mg/dl indicate high affinity of the enzyme (Ur) for urea detection.Conclusion: The results obtained from this study indicated that the Ur/PVA-nanoNiFe2O4/Au bioelectrode reveals increased enzyme (urease)-substrate (urea) interactions indicating the distinct advantage of this matrix over other matrices used for urea biosensor fabrication. Efforts should be made to use this electrode for the detection of urea in blood serum.Keywords: Biosensor, NiFe2O4nanoparticles, Urease (Ur), Polyvinyl alcohol (PVA), Nanobiocomposite, Sol-gel metho

Solid-state diffusion reaction and formation of intermetallic compounds in the nickel-zirconium system

Chemical diffusion studies in the nickel-zirconium system are investigated in the temperature range of 1046 to 1213 K employing diffusion couples of pure nickel and pure zirconium. Electron microprobe and X-ray diffraction studies have been employed to investigate the formation of different compounds and to study their layer growth kinetics in the diffusion zone. It is observed that growth of each phase is controlled by the process of volume diffusion as the layer growth obeys the parabolic law. The activation energies for interdiffusion in NiZr and NiZr2, which are the dominant phases in the diffusion zone, are 119.0 ±13.4 and 103.0 ±25.0 kJ/ mole, respectively. The formation and stability of compounds over the temperature range have been discussed on the basis of existing thermodynamic and kinetic data

Diffusion bonding of commercially pure titanium to 304 stainless steel using copper interlayer

Diffusion bonding was carried out between commercially pure titanium (cpTi) and 304 stainless steel (304ss) using copper as interlayer in the temperature range of 850–950 °C for 1.5 h under 3 MPa load in vacuum. The microstructures of the transition joints were revealed in optical and scanning electron microscopy (SEM). The study exhibits the presence of different reaction layers in the diffusion zone and their chemical compositions were determined by energy dispersive spectroscopy. The occurrence of different intermetallic compounds such as CuTi2, CuTi, Cu3Ti2, Cu4Ti3, FeTi, Fe2Ti, Cr2Ti, T2 (Ti40Cu60−xFex; 5 < x < 17), T3 (Ti43Cu57−xFex; 21 < x < 24) and T5 (Ti45Cu55−xFex; 4 < x < 5) has been predicted from the ternary phase diagrams of Fe–Cu–Ti and Fe–Cr–Ti. These reaction products were confirmed by X-ray diffraction technique. The maximum bond strength of 318 MPa (99.7% of Ti) was obtained for the couple bonded at 900 °C due to better coalescence of mating surface. With the rise in joining temperature to 950 °C, decrease in bond strength occurs due to formation of brittle Fe–Ti bases intermetallics. At a lower joining temperature of 850 °C, bond strength is also lower due to incomplete coalescence of the mating surfaces

Discovering Valuable Items from Massive Data

Suppose there is a large collection of items, each with an associated cost and an inherent utility that is revealed only once we commit to selecting it. Given a budget on the cumulative cost of the selected items, how can we pick a subset of maximal value? This task generalizes several important problems such as multi-arm bandits, active search and the knapsack problem. We present an algorithm, GP-Select, which utilizes prior knowledge about similarity be- tween items, expressed as a kernel function. GP-Select uses Gaussian process prediction to balance exploration (estimating the unknown value of items) and exploitation (selecting items of high value). We extend GP-Select to be able to discover sets that simultaneously have high utility and are diverse. Our preference for diversity can be specified as an arbitrary monotone submodular function that quantifies the diminishing returns obtained when selecting similar items. Furthermore, we exploit the structure of the model updates to achieve an order of magnitude (up to 40X) speedup in our experiments without resorting to approximations. We provide strong guarantees on the performance of GP-Select and apply it to three real-world case studies of industrial relevance: (1) Refreshing a repository of prices in a Global Distribution System for the travel industry, (2) Identifying diverse, binding-affine peptides in a vaccine de- sign task and (3) Maximizing clicks in a web-scale recommender system by recommending items to users

Peran Pendampingan Warga Peduli AIDS terhadap Kualitas Hidup Orang Dengan HIV-AIDS di Kecamatan Alak Kota Kupang

HIV-AIDS still be the global healthy problem which has higer number of morbidity and mortability cases. PLWA (People Live With AIDS) have often being denied by the others so the HIV-AIDS problem sometimes is undetected in the society, also give the influence towards the quality of PLWA’s life.&nbsp; The quality of life is the important component of life and welfare evaluation of the PLWA. Based on the data of Alak districst in 2018, the higest case was 185 cases of HIV-AIDS in which the HIV infectants were 102 cases, while people with AIDS were 83 cases.&nbsp; This research is purposed to describe the quality of life of People Live With HIV-AIDS in Alak district in 2019 whose got accompaniment from the WPA ( PCWA : People Who Care With AIDS) companions. This research was done by using descriptive qualitative method. The main informants of this research were two WPA (PCWA) companions and five PLWA whose got the accompaniment also supported by three triangulation informants. The technique of data collection of this research was indeep interview whith three steps of interactive analitical models which are Reduction, Data Presentation and conclusion drawing. The result of this research shows that the implementation of the role of the PCWA as the mentors of taking medication, social supporter, and health service access support was successful and gave the impact towards PLWA’s Life. It’s shown by looking to the improvement of physical aspect, psychological aspect, independency, social relationship, sociaty aspect and spiritual aspect. This accompaniment had occured for almost 4 years towards the PLWA. It was expected for the other people to participate helping the PCWA companions in order to support and conducive towards the PLWA so, they have better quality of life

A novel form of recessive limb girdle muscular dystrophy with mental retardation and abnormal expression of alpha-dystroglycan

Cataloged from PDF version of article.The limb girdle muscular dystrophies are a heterogeneous group of conditions characterized by proximal muscle weakness and disease onset ranging from infancy to adulthood. We report here eight patients from seven unrelated families affected by a novel and relatively mild form of autosomal recessive limb girdle muscular dystrophy (LGMD2) with onset in the first decade of life and characterized by severe mental retardation but normal brain imaging. Immunocytochemical studies revealed a significant selective reduction of α-dystroglycan expression in the muscle biopsies. Linkage analysis excluded known loci for both limb girdle muscular dystrophy and congenital muscular dystrophies in the consanguineous families. We consider that this represents a novel form of muscular dystrophy with associated brain involvement. The biochemical studies suggest that it may belong to the growing number of muscular dystrophies with abnormal expression of α-dystroglycan. © 2003 Published by Elsevier B.V

A MeerKAT view on galaxy clusters: a radio-optical study of Abell 1300 and MACS J1931.8--2634

In this paper we present results from a radio-optical study of the galaxy populations of the galaxy clusters Abell 1300 and MACS J1931.8$-$2634, a merger and a relaxed system respectively both located at $z \sim 0.3$, aimed at finding evidence of merger-induced radio emission. Radio observations are taken at 1.28 GHz with the MeerKAT interferometer during its early-stage commissioning phase, and combined with archive optical data. We generated catalogues containing 107 and 162 radio sources in the A$~$1300 and MACS J1931.8--2634 cluster fields respectively, above a 0.2 mJy threshold and within a 30~arcmin radius from the cluster centre (corresponding to 8.1 and 8.8 Mpc respectively). By cross-correlating the radio and optical catalogues, and including spectroscopic information, 9 and 6 sources were found to be cluster members and used to construct the radio luminosity functions respectively for both clusters. The comparison of the radio source catalogues between the two cluster fields leads to a marginal difference, with a $2\sigma$ statistical significance. We derived the radio luminosity function at 1.28 GHz in both clusters, in the power range $22.81 < \rm {log~P_{1.28~GHz}~(W/Hz)} < 25.95$, and obtained that in A 1300 the radio luminosity function averaged over the full radio power interval is only $3.3 \pm 1.9$ times higher than the MACS J1931.8--2634 one, suggesting no statistical difference in their probability to host nuclear radio emission. We conclude that, at least for the two clusters studied here, the role of cluster mergers in affecting the statistical properties of the radio galaxy population is negligible.Comment: 18 pages, 8 figures, MNRAS accepte

How and When Socially Entrepreneurial Nonprofit Organizations Benefit From Adopting Social Alliance Management Routines to Manage Social Alliances?

Social alliance is defined as the collaboration between for-profit and nonprofit organizations. Building on the insights derived from the resource-based theory, we develop a conceptual framework to explain how socially entrepreneurial nonprofit organizations (SENPOs) can improve their social alliance performance by adopting strategic alliance management routines. We test our framework using the data collected from 203 UK-based SENPOs in the context of cause-related marketing campaign-derived social alliances. Our results confirm a positive relationship between social alliance management routines and social alliance performance. We also find that relational mechanisms, such as mutual trust, relational embeddedness, and relational commitment, mediate the relationship between social alliance management routines and social alliance performance. Moreover, our findings suggest that different types of social alliance motivation can influence the impact of social alliance management routines on different types of the relational mechanisms. In general, we demonstrate that SENPOs can benefit from adopting social alliance management routines and, in addition, highlight how and when the social alliance management routines–social alliance performance relationship might be shaped. Our study offers important academic and managerial implications, and points out future research directions

MeerKAT's discovery of a radio relic in the bimodal merging cluster A2384

We present the discovery of a single radio relic located at the edge of the galaxy cluster A2384, using the MeerKAT radio telescope. A2384 is a nearby ($z$ = 0.092), low mass, complex bimodal, merging galaxy cluster that displays a dense X-ray filament ($\sim$ 700 kpc in length) between A2384(N) (Northern cluster) and A2384(S) (Southern cluster). The origin of the radio relic is puzzling. By using the MeerKAT observation of A2384, we estimate that the physical size of the radio relic is 824 $\times$ 264 kpc$^{2}$ and that it is a steep spectrum source. The radio power of the relic is $P_{1.4\mathrm{GHz}}$ $\sim$ (3.87 $\pm$ 0.40) $\times$ 10$^{23}$ W Hz$^{-1}$. This radio relic could be the result of shock wave propagation during the passage of the low-mass A2384(S) cluster through the massive A2384(N) cluster, creating a trail appearing as a hot X-ray filament. In the previous GMRT 325 MHz observation we detected a peculiar FR I radio galaxy interacting with the hot X-ray filament of A2384, but the extended radio relic was not detected; it was confused with the southern lobe of the FR I galaxy. This newly detected radio relic is elongated and perpendicular to the merger axis, as seen in other relic clusters. In addition to the relic, we notice a candidate radio ridge in the hot X-ray filament. The physical size of the radio ridge source is $\sim$ 182 $\times$ 129 kpc$^{2}$. Detection of the diffuse radio sources in the X-ray filament is a rare phenomenon, and could be a new class of radio source found between the two merging clusters of A2384(N) and A2384(S).Comment: 12 pages, 6 figures, accepted in MNRA