The hierarchical structure and properties of multifunctional carbon nanotube fibre composites

The axial mechanical, electrical and thermal properties of carbon nanotubes (CNTs) can be exploited macroscopically by assembling them parallel to each other into a fibre during their synthesis by chemical vapour deposition. Multifunctional composites with high volume fraction of CNT fibres are then made by direct polymer infiltration of an array of aligned fibres. The fibres have a very high surface area, causing the polymer to infiltrate them and resulting in a hierarchical composite structure. The electrical and thermal conductivities of CNT/epoxy composites are shown to be superior to those of equivalent specimens with T300 carbon fibre (CF) which is widely used in industry. From measurements of longitudinal coefficient of thermal expansion (CTE) of the composites we show that the CTE of CNT fibres is approximately ?1.6 × 10^?6 K^?1, similar to in-plane graphite. The combination of electrical, thermal and mechanical properties of CNT fibre composites demonstrates their potential for multifunctionality.     

Dispersion of multiwall carbon nanotubes in blends of polypropylene and acrylonitrile butadiene styrene

State of dispersion of purified multiwall carbon nanotubes (p‐MWNT) in the presence of neutralized MWNT (n‐MWNT) in aqueous solution was assessed through UV–Visible spectroscopy, dynamic light scattering measurements, and solution experiments. Raman spectroscopic analysis revealed that debundling of p‐MWNT in the presence of n‐MWNT in aqueous solution was persistent even in the solid mixture, which was supported by transmission electron microscopic analysis. The proposed mechanism behind the improved dispersion of p‐MWNT in the presence of n‐MWNT in aqueous solution has been based on the electrostatic charge repulsion between negatively charged n‐MWNT. The state of dispersion of p‐MWNT in the presence of n‐MWNT in 45/55 polypropylene/acrylonitrile butadiene styrene (PP/ABS) blends was assessed through Raman spectroscopic analysis, bulk electrical conductivity measurements, solution experiment, and crystallization studies. Raman spectroscopic analysis indicated that the state of dispersion of MWNT was improved with increasing n‐MWNT content of the mixture. This strategy led to a remarkable increase in the bulk electrical conductivity of 45/55 PP/ABS blends at 3 wt% MWNT content and was strongly dependent on the concentration of n‐MWNT in the mixture. Differential scanning calorimetric measurements along with solution experiments revealed the subsequent migration of MWNT from the PP phase to the ABS phase in the blends during melt‐mixing in the presence of higher fraction of n‐MWNT. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers     

Genome-Wide Identification of Aquaporin Genes in Adzuki Bean (Vigna angularis) and Expression Analysis under Drought Stress

The adzuki bean Vigna angularis (Wild.) is an important leguminous crop cultivated mainly for food purposes in Asian countries; it represents a source of carbohydrates, digestible proteins, minerals, and vitamins. Aquaporins (AQPs) are crucial membrane proteins involved in the transmembrane diffusion of water and small solutes in all living organisms, including plants. In this study, we used the whole genome sequence of the adzuki bean for in silico analysis to comprehensively identify 40 Vigna angularis aquaporin (VaAQP) genes and reveal how these plants react to drought stress. VaAQPs were compared with AQPs from other closely-related leguminous plants, and the results showed that mustard (Brassica rapa) (59), barrel medic (Medicago truncatula) (46), soybean (Glycine max) (66), and common bean (Phaseolus vulgaris L.) (41) had more AQP genes. Phylogenetic analysis revealed that forty VaAQPs belong to five subfamilies, with the VaPIPs (fifteen) subfamily the largest, followed by the VaNIPs (ten), VaTIPs (ten), VaSIPs (three), and VaXIPs (two) subfamilies. Furthermore, all AQP subcellular locations were found at the plasma membrane, and intron–exon analysis revealed a relationship between the intron number and gene expression, duplication, evolution, and diversity. Among the six motifs identified, motifs one, two, five, and six were prevalent in VaTIP, VaNIP, VaPIP, and VaXIP, while motifs one, three, and four were not observed in VaPIP1-3 and VaPIP1-4. Under drought stress, two of the VaAQPs (VaPIP2-1 and VaPIP2-5) showed significantly higher expression in the root tissue while the other two genes (VaPIP1-1 and VaPIP1-7) displayed variable expression in leaf tissue. This finding revealed that the selected VaAQPs might have unique molecular functions linked with the uptake of water under drought stress or in the exertion of osmoregulation to transport particular substrates rather than water to protect plants from drought. This study presents the first thorough investigation of VaAQPs in adzuki beans, and it reveals the transport mechanisms and related physiological processes that may be utilized for the development of drought-tolerant adzuki bean cultivars.     

Edible mushrooms: The potential game changer in alleviating vitamin D deficiency and improving human health

The present review attempts to critically examine and evaluate research findings on mushrooms as sources of vitamin D and other nutraceuticals. Recently, there is a growing concern about diseases associated with the deficiency of vitamin D in humans. As people tend to stay indoors, in present times, due to the COVID-19 pandemic, vitamin D levels are further affected. Research indicates vitamin D as a promising defensive or therapeutic agent against COVID, making this review more crucial. Mushrooms, as a rich source of vitamin D along with various bioactive compounds, perform a significant role in resolving health issues. Robust analyses of various strategies for enhancing vitamin D content in mushrooms holds significance in this study; moreover, this will help stakeholders of the mushroom industry in enriching the overall mushroom quality and human health. Mushroom-based medicinal formulations and functional foods serve to deliver vitamins and nutrients to humans, thus helping to combat malnutrition and other health problems, especially in developing countries. Evidence from pre-clinical and clinical analyses suggests that vitamin D₂ bioavailability in mushrooms is comparable with vitamin D from other sources. The review also emphasises molecular findings from mushrooms related to genes responsible for morphology and metabolic production of pro-vitamin-D₂.     

Visual saliency guided video compression algorithm

Recently Saliency maps from input images are used to detect interesting regions in images/videos and focus on processing these salient regions. This paper introduces a novel, macroblock level visual saliency guided video compression algorithm. This is modelled as a 2 step process viz. salient region detection and frame foveation. Visual saliency is modelled as a combination of low level, as well as high level features which become important at the higher-level visual cortex. A relevance vector machine is trained over 3 dimensional feature vectors pertaining to global, local and rarity measures of conspicuity, to yield probabilistic values which form the saliency map. These saliency values are used for non-uniform bit-allocation over video frames. To achieve these goals, we also propose a novel video compression architecture, incorporating saliency, to save tremendous amount of computation. This architecture is based on thresholding of mutual information between successive frames for flagging frames requiring re-computation of saliency, and use of motion vectors for propagation of saliency values.     

Low substrate temperature deposition of transparent and conducting ZnO: Al thin films by RF magnetron sputtering

Transparent and conducting Al-doped ZnO(ZnO:Al) films were prepared on glass substrate using the RF sputtering method at different substrate temperatures from room temperature(RT) to 200 ℃. The structural,morphological, electrical and optical properties of these films were investigated using a variety of characterization techniques such as low angle XRD, Raman spectroscopy, X-ray photoelectron spectroscopy(XPS), field-emission scanning electron microscopy(FE-SEM), Hall measurement and UV–visible spectroscopy. The electrical properties showed that films deposited at RT have the lowest resistivity and it increases with an increase in the substrate temperature whereas carrier mobility and concentration decrease with an increase in substrate temperature. Low angle XRD and Raman spectroscopy analysis reavealed that films are highly crystalline with a hexagonal wurtzite structure and a preferred orientation along the c-axis. The FE-SEM analysis showed that the surface morphology of films is strongly dependent on the substrate temperature. The band gap decreases from 3.36 to 3.29 e V as the substrate temperature is increased from RT to 200 ℃. The fundamental absorption edge in the UV region shifts towards a longer wavelength with an increase in substrate temperature and be attributed to the Burstein-Moss shift. The synthesized films showed an average transmission(> 85%) in the visible region, which signifies that synthesized ZnO:Al films can be suitable for display devices and solar cells as transparent electrodes.     

Creation and manipulation of surface magnetic domains in an alternating up-and-down pattern

According to Lenz's law, the magnetic field from the oscillating magnetic probe will induce out-of-plane surface magnetic domains (SMDs) from the in-plane magnetization at the locally tapped points on a ferromagnetic La(0.7)Sr(0.3)MnO3 (LSMO) thin film. It was possible to control and manipulate the out-of-plane SMDs by varying the tapping intervals and changing the scanning direction. We also found that the anisotropic stresses from the out-of-plane SMDs caused the appearance of large-area straight striped domain structures on the order of several micrometers. Smaller oscillating magnetic probe tapping intervals produced larger periods (or widths) of the straight striped domain structure.     

Evaluation of extraction methods for ochratoxin A detection in cocoa beans employing HPLC

Cocoa is an important ingredient for the chocolate industry and for many food products. However, it is prone to contamination by ochratoxin A (OTA), which is highly toxic and potentially carcinogenic to humans. In this work, four different extraction methods were tested and compared based on their recoveries. The best protocol was established which involves an organic solvent-free extraction method for the detection of OTA in cocoa beans using 1% sodium hydrogen carbonate (NaHCO₃) in water within 30 min. The extraction method is rapid (as compared with existing methods), simple, reliable and practical to perform without complex experimental set-ups. The cocoa samples were freshly extracted and cleaned-up using immunoaffinity column (IAC) for HPLC analysis using a fluorescence detector. Under the optimised condition, the limit of detection (LOD) and limit of quantification (LOQ) for OTA were 0.62 and 1.25 ng ml^–1 respectively in standard solutions. The method could successfully quantify OTA in naturally contaminated samples. Moreover, good recoveries of OTA were obtained up to 86.5% in artificially spiked cocoa samples, with a maximum relative standard deviation (RSD) of 2.7%. The proposed extraction method could determine OTA at the level 1.5 µg kg^–1, which surpassed the standards set by the European Union for cocoa (2 µg kg^–1). In addition, an efficiency comparison of IAC and molecular imprinted polymer (MIP) column was also performed and evaluated.     

Ambient temperature hydrogen storage in porous materials with exposed metal sites

Cross-linked porous polymeric complexes with exposed metal sites are synthesized for room temperature hydrogen storage via physisorption. At 298 K and 100 atm, PTF-Cr exhibits high excess hydrogen storage capacity up to 1.5 wt% with Qst of 11.5 kJ mol^?1 while PTF-Mg exhibits 0.5 wt% with Qst of 8 kJ mol^?1. The result provides insight for development of future storage materials with exposed transition metals.