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Paper-based nucleic acid amplification tests for point-of-care diagnostics
No full textThere has been a recent resurgence in the use of paper as a substrate for developing point-of-care medical diagnostic tests, possibly triggered by expiring patents published in the 1990s. A hallmark of this resurgence has been the development of advanced shapes and structures made from paper to conduct multi-step fluidic operations using the wicking action of porous materials. Such devices indicate a distinct improvement over lateral flow immunoassays, which are restricted to conducting one-step operations. New developments in paper-based diagnostic devices have triggered interest in the development of paper-based point-of-care nucleic acid amplification tests (NAATs). NAATs can identify extremely low levels of specific nucleic acid sequences from clinical samples and are the most sensitive of all available tests for infectious disease diagnosis. Because traditional PCR-based NAATs require expensive instruments, the development of portable paper-based NAAT's has become an exciting field of research. This article aims to review and analyse the current state of development of paper-based NAATs. We project paper-based NAATs as miniaturized chemical processes and shed light on various schemes of operation used for converting the multiple steps of the chemical processes into paper microfluidic devices. We conclude by elaborating on the challenges that must be overcome in the near future so that progress can be made towards the development of fully functional and commercial paper-based NAATs
Simulating potential yields of Chinese super hybrid rice in Bangladesh, India and Myanmar with EPIC model
No full textIn this study, information is collected on the weather, soils, field management and agricultural statistics in the Bangladesh, India and Myanmar (BIM) region. Crop growth parameters within the EPIC (Environmental Policy Integrated Climate) model are calibrated using cultivar data and regional experimental records of indica hybrid rice Fyou498 and Fengliangyou4 in China. Potential yields of rice are then simulated in the BIM region from 1996 to 2005. The effects of local irrigation and fertilization levels on super hybrid rice yield are examined. The potential yields of Chinese hybrid rice at local irrigation and fertilization levels in 2000 and at full irrigation and rational fertilization levels are found to be 10.22 t/ha and 11.33 t/ha, respectively. The potential for increasing monsoon rice production in the study region is 227.71 million tons. The eastern Indo-Gangetic Plain in India, the southeast coast of India Peninsula and the Ayeyarwady Delta in Myanmar have the largest potentials for monsoon rice production. The northeastern and southwestern areas of the Deccan Plateau and the northwestern region of the Indo-Gangetic Plain need to improve irrigation equipment to meet the water-use requirements of high-yield rice. The central and southern plains in Myanmar and northeastern India need greater access to nitrogen fertilization for high-yield rice
Effect of annealing temperature on the structural and magnetic properties of Ba-Pb-hexaferrite powders synthesized by sol-gel auto-combustion method
No full textThe annealing temperature (T-a) dependent development in phase purity, morphology and magnetic properties of BaxPb1-xFe12O19 (x = 0, 0.2, 0.4, 0.6, 0.8 and 1) powders synthesized via sol-gel auto-combustion route were studied. The hexagonal phase of PbFe12O19 forms directly via solid-state-reaction between alpha-Fe2O3 and PbO during annealing of the combustion product at T-a similar to 900 degrees C, but the BaFe12O9 phase forms at T-a similar to 1200 degrees C through the formation of BaFe2O4 and alpha-Fe2O3 as intermediate-phases at low T-a. The BaxPb1-xFe12O19-phase purity of the samples depend on T-a. For T-a > 1000 degrees C, PbO evaporates from Pb-containing samples. With increasing T-a, growth of hexagonal-shaped sharp-edged particles was observed for Barium-rich samples, however, the sharp-edges dissolute for Lead-rich samples. High saturation magnetization was observed for Ba-rich samples annealed at 1100 degrees C. For all the studied samples, magnetic coercivity increases with x but decreases with T-a. The magnetic properties were correlated with the structure, microstructure and grain-size of the samples
On the Occurrences of Japalura kumaonensis and Japalura tricarinata (Reptilia: Sauria: Draconinae) in China
No full textAlthough the recognized distribution of Japalura kumaonensis is restricted largely to western Himalaya, a single, isolated outlier population was reported in eastern Himalaya at the China-Nepal border in southeastern Tibet, China in Zhangmu, Nyalam County. Interestingly, subsequent studies have recognized another morphologically similar species, J. tricarinata, from the same locality in Tibet based on photographic evidence only. Despite these reports, no studies have examined the referred specimens for either record to confirm their taxonomic identifications with robust comparisons to congener species. Here, we examine the referred specimen of the record of J. kumaonensis from southeastern Tibet, China; recently collected specimens from the same locality in southeastern Tibet; type specimens; and topotypic specimens of both J. kumaonensis and J. tricarinata, to clarify the taxonomic identity of the focal population from southeastern Tibet, China. Our results indicate that individuals of the referred Tibetan population differ from J. kumaonensis in external morphology, but match descriptions and specimens of J. tricarinata. We conclude that the previous record of J. kumaonensis from Tibet was a misidentification of J. tricarinata, and J. kumaonensis should be recognized as occurring in western Himalaya only. To facilitate future taxonomic studies of the genus Japalura sensu lato in the Himalaya, we provide a detailed description of J. tricarinata and an updated diagnostic key to the genus from the Himalaya
Femtosecond Time-Resolved Raman Spectroscopy Reveals Structural Evidence for meta Effect in Stilbenols
No full textThe met a effect in substituted aromatics plays a crucial role in their excited-state photophysical properties. Meta-substituted hydroxyarenes such as naphthols, stilbenols, and chromophoric constituents of green fluorescent proteins show unusual photoacidity and enhanced fluorescence lifetime and quantum yield when compared to their para-derivatives. Variation in the excited state features of the meta-derivatives when compared to the para-derivatives in stilbenols has been attributed to the enhanced torsional barrier for interconversion between the planar and the twisted perpendicular forms. Herein, we employed femtosecond time-resolved Raman spectroscopy to provide the direct structural evidence for the enhanced torsional barrier in meta-stilbenol. The Raman band profiles of the olefinic C=C stretch related to the torsional motion are found to decay with time constants of similar to 750 and similar to 13 ps in meta-stilbenol and para-stilbenol respectively, unraveling the structural evidence for the observed enhanced photoacidity originating from enhanced rates of excited-state proton transfer. Further, time-resolved fluorescence measurements are performed to elucidate the relaxation pathways of the excited states of the stilbenols
A pH stimuli thiol modified mesoporous silica nanoparticles: Doxorubicin carrier for cancer therapy
No full textMesoporous silica nanoparticles (MSN) have been attracted in the field of biomedicine due to their versatile properties as a drug nanocarrier. In this research, MSN and thiol modified MSN (mMSN) were synthesized to be the drug nanocarriers, by the sol-gel technique for the efficient delivering doxorubicin hydrochloride (DOX). These carriers were characterized by Transmission Electron Microscopy (TEM), Field Emission Scanning Electron Microscopy (FESEM), SA3100 analyzer (Brunauer-Emmett-Teller), Zetasizer and Fourier transform infrared spectroscopy (FTIR). FESEM observation revealed that these particles have uniform sizes and the zeta potential analysis confirmed the existence of surface charge and stability of the particles. Brunauer-Emmett-Teller showed that MSN and mMSN are characteristic type IV N-2 adsorption/desorption patterns. The in vitro drug release profile studies have profound that the drug-loaded carriers were pH dependent and the drug-loaded mMSN (DOX@mMSN) displayed a faster drug release at the acidic pH with tumor cells than the pH with normal cells. Cell cycle arrest and ROS generation were analyzed by Fluorescence-activated cell sorting. Assay on the cytotoxicity against the HeLa cells showed a better antitumor effect with DOX@mMSN compared to DOX@MSN. This study attested that pH -responsive thiol modified drug nanocarrier can have the potential cancer therapy. (C) 2018 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved
Spectroscopic Analysis of Lead Borate Systems
No full textOxide glass systems are, interesting because of their bonding like bridging and non -bridging oxygens. Depending on the modifier, the B2O3 glass system can have various Boron -Oxygen network. It is found that, MO modifies the borate network and increases the formation of penta and diborate groups. In this work, we investigated optical properties of lead Borate glass systems (x PbO: (1-x) B2O3) with x varying from 30 - 85 mol % using UV-VIS Spectra and the corresponding band gap was estimated using Tauc relation and these systems behave like direct allowed band gap systems. These results show that, E(g)decreases with the addition of lead content. Further the refractive index measurements also have been carried out at various wavelengths.Many correlation is found between the band gap and refractive index for different compositions. Using different theoretical models a best fit has been tried and Ravindra's relation is found to match with our experimental results
Optimization of Wood Plastic Composite Decks
No full textWood Plastic Composite (WPC) is a new class of natural fibre based composite material that contains plastic matrix reinforced with wood fibres or wood flour. In the present work, Wood Plastic Composite was prepared with 70-wt% of wood flour reinforced in polypropylene matrix. Mechanical characterization of the composite was done by carrying out laboratory tests such as tensile test and flexural test as per the American Society for Testing and Materials (ASTM) standards. Computer Aided Design (CAD) model of the laboratory test specimen (tensile test) was created and explicit finite element analysis was carried out on the finite element model in non-linear Explicit FE code LS - DYNA. The piecewise linear plasticity (MAT 24) material model was identified as a suitable model in LS-DYNA material library, describing the material behavior of the developed composite. The composite structures for decking application in construction industry were then optimized for cross sectional area and distance between two successive supports (span length) by carrying out various numerical experiments in LS-DYNA. The optimized WPC deck (Elliptical channel-2 E10) has 45% reduced weight than the baseline model (solid cross-section) considered in this study with the load carrying capacity meeting acceptance criterion (allowable deflection & stress) for outdoor decking application
Enhancement of High Temperature Strength of 2219 Alloys Through Small Additions of Nb and Zr and a Novel Heat Treatment
No full textThis paper presents a detailed investigation on the effect of small amount of Nb and Zr additions to 2219 Al alloy coupled with a novel three-stage heat treatment process. The main aim of the work is to increase the high temperature strength of 2219 alloy by introducing thermally stable L1(2) type ordered precipitates in the matrix as well as by reducing the coarsening of metastable strengthening theta aEuro(3) and theta' precipitates. To achieve this, small amounts of Nb and Zr are added to 2219 alloy melt and retained in solid solution by suction casting in a water-cooled copper mould having a cooling rate of 10(2) to 10(3) K/s. The suction cast alloy is directly aged at 673 K (400 A degrees C) to form L1(2) type ordered coherent Al3Zr precipitates. Subsequently, the alloy is solution treated at 808 K (535 A degrees C) for 30 minutes to get supersaturation of Cu in the matrix without significantly affecting the Al3Zr precipitates. Finally, the alloy is aged at 473 K (200 A degrees C), which results in the precipitation of theta aEuro(3) and theta'. Microstructural characterization reveals that theta aEuro(3) and theta' are heterogeneously precipitated on pre-existing uniformly distributed Al3Zr precipitates, which leads to a higher number density of these precipitates. This results in a significant increase in strength at room temperature as well as at 473 K (200 A degrees C) as compared to the 2219 alloy. Furthermore, the alloy remains thermally stable after prolonged exposure at 473 K (200 A degrees C), which is attributed to the elastic strain energy minimization by the conjoint Al3Zr/theta' or Al3Zr/theta aEuro(3) precipitates, and the high Zr and Nb solute-vacancy binding energy, retarding the growth and coarsening of theta aEuro(3) and theta' precipitates