The spin-1/2 coupled tetramer system Ba(TiO)Cu4_4(PO4_4)4 _4 probed by magnetization, specific heat, and 31^{31}P-NMR

We present the synthesis and a detailed investigation of structural and magnetic properties of polycrystalline Ba(TiO)Cu$_{4}$(PO$_{4}$)$_{4}$ (BTCPO) via x-ray diffraction, magnetic susceptibility, heat capacity, and $^{31}$P Nuclear Magnetic Resonance (NMR) measurements. BTCPO has a 2D layered structure with interlinked Cu$_{4}$O$_{12}$ tetramer units. A broad maximum is observed around 16.5 K in our magnetization data accompanied by a sharp anomaly around $T$ = 9.5 K in the heat capacity. An anomaly at $T$ = 9.5 K is also found in the temperature dependence of the $^{31}$P NMR spin-lattice relaxation rate $1/T_1$. A power law behavior for the heat capacity as well as for the $^{31}$P $1/T_1$ below the ordering temperature could be obtained. The $^{31}$P NMR lineshape is asymmetric and the NMR shift tracks the bulk spin-susceptibility. We estimated the isotropic and axial components of the hyperfine coupling tensor to be as the $A^{iso}_{hf} \backsimeq 6794$ $\rm{Oe/\mu_{B}}$ and $A^{ax}_{hf} \backsimeq 818$ $\rm{Oe/\mu_{B}}$, respectively.Comment: 8 pages, 3 tables, 13 figure

Automatic modulation classification for cognitive radios using cumulants based on fractional lower order statistics

Automatic modulation classification (AMC) finds various applications in cognitive radios. This paper presents a method for the automatic classification using cumulants derived using fractional lower order statistics. The performance of the classifier is presented in the form of probability of correct classification under noisy and fading conditions. Unlike many of the conventional methods, the proposed method does not require a priori knowledge of signal parameters. The proposed method is also more robust to different noises. Simulation results show that the proposed method can achieve better classification accuracy when compared to conventional cumulant based AMC method, in various impulsive noise conditions. 1

The role of growth atmosphere on the structural and optical quality of defect free ZnO films for strong ultraviolet emission

Highly c-axis oriented wurtzite structured ZnO thin films were deposited on silicon substrates using pulsed laser deposition (PLD) by ablating a ZnO target in different atmospheres, including vacuum, argon and oxygen in the deposition chamber. The stress in the films was shown to vary from −3.83 to −0.03 GPa as a function of the chamber atmosphere. The minimum compressive stress (−0.03 GPa) was observed for the oxygen atmosphere. X-ray photoelectron spectroscopy data indicated that the O1s peak consists of three components designated as O1 (due to ZnO), O2 (due to defects) and O3 (due to adsorbed species). A small defect level emission was obtained in the luminescence spectra of the ZnO film deposited in the oxygen atmosphere, while strong ultraviolet (UV) emission was observed for the ZnO films deposited in the vacuum and argon atmosphere. These PLD grown ZnO thin films have the potential to be used as sources of UV radiation in light emitting devices.The authors want to thank to the National Laser Centre, CSIR, Pretoria for providing pulsed laser deposition technique. This work is based on the research supported by the South African Research Chairs Initiative of the Department of Science and Technology, and the National Research Foundation of South Africa. The PL system used in this study is supported both technically and financially by the rental pool programme of the National Laser Centre. The financial support from the Cluster program of the University of the Free State is highly recognized.Highly c-axis oriented wurtzite structured ZnO thin films were deposited on silicon substrates using pulsed laser deposition (PLD) by ablating a ZnO target in different atmospheres, including vacuum, argon and oxygen in the deposition chamber. The stress in the films was shown to vary from −3.83 to −0.03 GPa as a function of the chamber atmosphere. The minimum compressive stress (−0.03 GPa) was observed for the oxygen atmosphere. X-ray photoelectron spectroscopy data indicated that the O1s peak consists of three components designated as O1 (due to ZnO), O2 (due to defects) and O3 (due to adsorbed species). A small defect level emission was obtained in the luminescence spectra of the ZnO film deposited in the oxygen atmosphere, while strong ultraviolet (UV) emission was observed for the ZnO films deposited in the vacuum and argon atmosphere. These PLD grown ZnO thin films have the potential to be used as sources of UV radiation in light emitting devices

Tropical storm off Myanmar coast sweeps reefs in Ritchie’s Archipelago, Andaman

The reefs in some islands of Andaman and Nicobar suffered severe damage following a tropical storm in the Bay of Bengal off Myanmar coast during 13–17 March 2011. Surveys were conducted at eight sites in Andaman, of which five were located in the Ritchie’s Archipelago where maximum wind speeds of 11 ms-1 was observed; and three around Port Blair which lay on the leeward side of the storm and had not experienced wind speeds of more than 9 ms-1. Corals in the shallow inshore reefs were broken and dislodged by the thrust of the waves. Significant damage in the deeper regions and offshore reefs were caused by the settlement of debris and sand brought down from the shallower regions. The fragile branching corals (Acropora sp.) were reduced to rubbles and the larger boulder corals (Porites sp.) were toppled over or scarred by falling debris. The reefs on the windward side and directly in the path of the storm winds were the worst affected. The investigation exposes the vulnerability of the reefs in Andaman to the oceanographic features which generally remain unnoticed unless the damage is caused to the coastal habitats

APTAMER: A REVIEW ON IT’S IN VITRO SELECTION AND DRUG DELIVERY SYSTEM

In recent year, Aptamer has been one of the key tools in the field of advanced drug delivery systems. Aptamer are oligonucleotides or peptides that bind to a specific target molecule. In this review we summarize the major differences between the antibody and an Aptamer along with the different methodology of the In vitro selection of the Aptamer by using SELEX (Systematic evolution of ligands by exponential enrichment) technique. SELEX is a technique which has a based biosensor and some of the novel drug delivery system. The article referred in this review was referred from the above said source was in the range of 1990-2020 y. Primary contents is searched from science direct, springer nature, scopus indexed journals. The resources are downloaded from google scholar, peer-reviewed published literature from scientific journals and books

Short-Term Effect of Forage Grasses on Carbon Sustainability, Fodder Security, and Soil Properties in Poor Soils of Semi-Arid India

Grasses are essential sources of fodder for livestock and provide options for climate resilience due to their broad range of adoption. They are also valuable resources for soil quality enhancement. Therefore, a six-year field study using nine grasses (2013 to 2019) was initiated in a semi-arid region of central India. The study aimed to assess the short-term impact of these nine grasses on soil carbon stock, selected soil physiochemical and biological properties, and green fodder yield. Results (after six years) revealed that a greater carbon stock (7.0 and 7.2 Mg ha–1), carbon sustainability index (71.6 and 89.3), and sustainable yield index for green fodder (0.89 and 0.91), respectively, were observed in lampagrass [Heteropogon contortus (L.)] and guineagrass [Megathyrsus maximus(Jacq.)]. These improvements could be due to the greater root length (1700 and 2220 cm plant–1) and root weight density of grasses in the upper soil layer (0–10 cm, 70%), and the higher green biomass production (~44.1 t ha–1 year–1). These beneficial changes might have further led to the lower soil bulk density (~1.05 g cm–3), higher water-filled porosity (14.7 and 16.1%), and soil organic carbon content (~0.67%) over other grasses and barren soil. Consequently, the highest total bacterial count (21.9 and 44.5 × 107 CFU g–1), soil microbial biomass carbon and enzyme activities such as acid phosphatase (17.7 and 22.6 µg p-nitrophenyl g–1 h–1) and alkaline phosphatase (9.6 and 15.9 µg p-nitrophenyl g–1 h–1) were noticed in lampagrass and guineagrass rhizospheres. Therefore, cultivation of perennial grasses in the low fertile soils of semi-arid environments can be an eco-friendly approach to enhance soil fertility, green fodder supply, and soil carbon build-up

Conformational transitions of the sodium-dependent sugar transporter, vSGLT.

Sodium-dependent transporters couple the flow of Na+ ions down their electrochemical potential gradient to the uphill transport of various ligands. Many of these transporters share a common core structure composed of a five-helix inverted repeat and deliver their cargo utilizing an alternating-access mechanism. A detailed characterization of inward-facing conformations of the Na+-dependent sugar transporter from Vibrio parahaemolyticus (vSGLT) has previously been reported, but structural details on additional conformations and on how Na+ and ligand influence the equilibrium between other states remains unknown. Here, double electron-electron resonance spectroscopy, structural modeling, and molecular dynamics are utilized to deduce ligand-dependent equilibria shifts of vSGLT in micelles. In the absence and presence of saturating amounts of Na+, vSGLT favors an inward-facing conformation. Upon binding both Na+ and sugar, the equilibrium shifts toward either an outward-facing or occluded conformation. While Na+ alone does not stabilize the outward-facing state, gating charge calculations together with a kinetic model of transport suggest that the resting negative membrane potential of the cell, absent in detergent-solubilized samples, may stabilize vSGLT in an outward-open conformation where it is poised for binding external sugars. In total, these findings provide insights into ligand-induced conformational selection and delineate the transport cycle of vSGLT

Instruments of RT-2 Experiment onboard CORONAS-PHOTON and their test and evaluation V: Onboard software, Data Structure, Telemetry and Telecommand

The onboard software and data communication in the RT-2 Experiment onboard the Coronas-Photon satellite is organized in a hierarchical way to effectively handle and communicate asynchronous data generated by the X-ray detectors. A flexible data handling system is organized in the X-ray detector packages themselves and the processing electronic device, namely RT-2/E, has the necessary intelligence to communicate with the 3 scientific payloads by issuing commands and receiving data. It has direct interfacing with the Satellite systems and issues commands to the detectors and processes the detector data before sending to the satellite systems. The onboard software is configured with several novel features like a) device independent communication scheme, b) loss-less data compression and c) Digital Signal Processor. Functionality of the onboard software along with the data structure, command structure, complex processing scheme etc. are discussed in this paper.Comment: 24 pages, 2 figures, Accepted for publication in Experimental Astronomy (in press