Electrical conductivity of microbially treated geomaterials and industrial wastes

Electrical conductivity measurement of geomaterials is often used as a tool for performance appraisal of liner materials, including monitoring of solute transport, and necessarily constitutes a vital aspect in the design of barrier systems. Variations of thermal conductivity of certain geomaterials along with industrial wastes for engineered barrier applications, as in the case of a deep geological repository (DGR), have been observed to vary with addition of a radiation-resistant microbial species. As there is an interdependence between thermal and electrical conductivity of geomaterials, in the present study, experimental investigations pertaining to microbial influence on electrical conductivities of several geomaterials and industrial-waste samples meant for barrier and buffer applications are reported. Electrical conductivity measurements of the samples were carried out with the help of a fabricated electrical conductivity probe with a microcontroller unit. It is observed that Deinococcus radiodurans, the extremophilic and radiation-resistant bacterial species, has an incremental effect on the shortterm electrical conductivity of the samples under consideration, which may be reasoned to any possible form of biogeochemical reaction leading to salt precipitation and subsequent alteration of salinity, or phasal augmentation in the liquid phase in the samples. Moreover, to appreciate the potential of living matter in soil to alter the engineering properties of the soil, a novel theoretical approach is also suggested to incorporate the presence of living phase in the idealized model of soil mass. Furthermore, based on the experimental data, prediction models are developed using artificial intelligence techniques and multigene genetic programming to quantify microbial influence on electrical conductivity of the samples. The models were found to be efficient in terms of statistical parameters. (C) 2017 American Society of Civil Engineers

In-situ Elevated Temperature Mechanical Performance of MWCNT/epoxy Nanocomposite

The present investigation has been focused on the effects of multi-walled carbon nanotube (MWCNT) addition on the mechanical performance of epoxy under different in-service elevated temperature environments. Room temperature flexural test results revealed that addition of 0.1 wt. % MWCNT into epoxy resin resulted in modulus and strength enhancement of 21 % and 9 % respectively. With increase in service temperature, significant decrement in both modulus and strength was noticed for both materials (neat epoxy and MWCNT/epoxy nanocomposite), but the rate of degradation was found to be quite drastic for the nanocomposite. At 90 °C temperature, the CNT/epoxy nanocomposite exhibited inferior modulus and strength, which are 41 % and 59 % lower than neat epoxy respectively. The variation trend in elastic modulus with temperature obtained from both flexural testing and DMA for both these materials was also analyzed. It was found that addition of 0.1 % CNT in the epoxy reduced the glass transition temperature by about 16°C

An improvised one-step sucrose cushion ultracentrifugation method for exosome isolation from culture supernatants of mesenchymal stem cells

Abstract Background Exosomes are nanovesicles (30–120 nm) of endosomal origin. These exosomes contain various functional proteins and RNAs that could be used for therapeutic purposes. Currently, having a standard method for exosome isolation retaining its biological properties with increased yield and purity is a major challenge. The most commonly used method is differential ultracentrifugation but it has its own disadvantages, which include high time consumption, low yield due to disruption of exosome integrity, and high protein contaminants. In this study, we have identified an improved method addressing these problems for exosome isolation using ultracentrifugation since it is cost-effective and used worldwide. Method We have compared differential ultracentrifugation with the modified method called one-step sucrose cushion ultracentrifugation for exosome isolation. The conditioned serum-free media from human mesenchymal stem cells cultured for 48 h was collected for exosome isolation. The cellular debris was removed by centrifugation at 300g for 10 min, followed by centrifugation at 10,000g for 30 min to remove microvesicles. Equal volumes of pre-processed conditioned media were used for exosome isolation by direct ultracentrifugation and one-step sucrose cushion ultracentrifugation. The exosomes isolated using these methods were characterized for their size, morphology, concentration, and surface marker protein expression. Result It was observed that the recovery of exosomes with cup-shaped morphology from one-step sucrose cushion ultracentrifugation was comparatively high as estimated by nanoparticle tracking analysis and electron microscopy. These results were confirmed by Western blotting and flow cytometry. Conclusion We conclude that this one-step sucrose cushion ultracentrifugation method provides an effective and reproducible potential standard method which could be used for various starting materials for isolating exosomes. We believe that this method will have a wide application in the field of extracellular vesicle research where exosome isolation with high yield and purity is an imperative step. Graphical abstract Schematic representation of comparison of UC and SUC exosome isolation methods for tissue-specific human mesenchymal stem cells. The SUC isolation method yields a greater number of cup-shaped exosomes with a relatively homogenous population for mass-scale production of exosomes for downstream analysis. Abbreviations: SUC One-step sucrose cushion ultracentrifugation, UC Direct ultracentrifugation

A comprehensive study of the estuary sea environment in the Bay of Bengal, near the Mahanadi River confluence

Abstract This study focuses on the environmental conditions of the Mahanadi Estuary near Paradeep Harbor and the adjacent sea. Data collected from May 2013 to April 2020 from 32 GPS fixed stations was analyzed to assess the water quality in different zones (estuarine, mixed zone, mixed zone south, and mixed zone north) of study area. Parameters such as pH, SST, TSS, nitrite, phosphate, silicate, TOC, chlorophyll, fecal coliform, and heavy metals were used to estimate the Water Quality Index (WQI) for each zone. The study found a deterioration (> 30%) in the overall water quality of the Mahanadi Estuary from 2013 to 2020, potentially attributed to river inflows, port activities, and industrial outflows in to the coastal ecosystem. Seasonal variations in temperature, salinity, turbidity, nitrite, nitrate, and ammonia were observed. The water quality showed a deteriorating trend in estuarine, mixed zone, mixed zone south, and mixed zone north. Based on the water quality indices, the ecosystem shows moderate levels of stress. The degraded water quality highlights the need for a targeted mitigation plan to reduce external pressures and enhance the overall ecosystem quality. Graphical Abstrac