Synthesis of Magnesium Based Nano-composites

Magnesium based nanocomposites are new lightweight and high-performance materials for potential applications in automotive, aerospace, space, electronics, sports and biomedical sectors primarily due to their lower density when compared to aluminum-based materials and steels. Synthesis of magnesium-based materials is relatively challenging and accordingly this chapter explicitly provides an insight into various techniques hitherto devised/adopted by various researcher for synthesizing magnesium based nano-composites (MMNCs). Overall processing of MMNCs often includes combination of primary and secondary processing. Primary processing fundamentally leads to the initial formulation and creation of MMNC ingots by solid, semi-solid or liquid state processing routes. This is followed by secondary processing that includes plastic deformation or severe plastic deformation to alleviate inhomogeneity, clustering of particles and fabrication defects to enhance the properties of the MMNCs. This chapter provides an insight into different fabrication methodologies, their benefits and limitations for MMNCs

INFLUENCE OF DIFFERENT INTERFACE MATERIALS AND OPENINGS IN INFILL OF REINFORCED CONCRETE INFILLED FRAMES

This study analytically investigates the behaviour of trapezoidal infilled frames (TIFs) with brick masonry infills having openings and various interface materials between the brick panel and reinforced concrete frame. Single-storey single-bay frame specimens are analysed under in-plane static loading. For this investigation, the optimum angle of the column inclination for the trapezoidal frame must be determined in terms of maximum lateral stiffness. The optimum angle must be further analysed and compared with rectangular bare and infilled frames, with various materials of the interface. This infilled frame is extended to analyse the openings in the infill further. To study the effects of openings in infilled panels, TIFs with different sizes and positions of window openings are analysed and compared with the rectangular frame. This study further analyses three different combinations of interfaces and determines the intermediate stiffness of the frame combination. The main focus of this investigation is to reduce the high rigidity of the TIF leading to high base shear. It is found that, the infilled frame is stiffer than the bare frame, and the cement mortar interface is stiffer than the lead–cork interface. This research uses ABAQUS software, a finite element analysis program, for expanding the observational analysis

Peptide-based direct electrochemical detection of receptor binding domains of SARS-CoV-2 spike protein in pristine samples

RNA isolation and amplification-free user-friendly detection of SARS-CoV-2 is the need of hour especially at resource limited settings. Herein, we devised the peptides of human angiotensin converting enzyme-2 (hACE-2) as bioreceptor at electrode interface for selective targeting of receptor binding domains (RBD) of SARS-CoV-2 spike protein (SP). Disposable carbon-screen printed electrode modified with methylene blue (MB) electroadsorbed graphene oxide (GO) has been constructed as cost-efficient and scalable platform for hACE-2 peptide-based SARS-CoV-2 detection. In silico molecular docking of customized 25 mer peptides with RBD of SARS-CoV-2 SP were validated by AutoDock CrankPep. N-terminal region of ACE-2 showed higher binding affinity of − 20.6 kcal/mol with 15 H-bond, 9 of which were < 3 Å. Electrochemical biosensing of different concentrations of SPs were determined by cyclic voltammetry (CV) and chronoamperometry (CA), enabling a limit of detection (LOD) of 0.58 pg/mL and 0.71 pg/mL, respectively. MB-GO devised hACE-2 peptide platform exert an enhanced current sensitivity of 0.0105 mA/pg mL(−1) cm(−2) (R(2) = 0.9792) (CV) and 0.45 nA/pg mL(−1) (R(2) = 0.9570) (CA) against SP in the range of 1 pg/mL to 1 µg/mL. For clinical feasibility, nasopharyngeal and oropharyngeal swab specimens in viral transport medium were directly tested with the prepared peptide biosensor and validated with RT-PCR, promising for point-of-need analysis

Chitin Scaffolds in Tissue Engineering

Tissue engineering/regeneration is based on the hypothesis that healthy stem/progenitor cells either recruited or delivered to an injured site, can eventually regenerate lost or damaged tissue. Most of the researchers working in tissue engineering and regenerative technology attempt to create tissue replacements by culturing cells onto synthetic porous three-dimensional polymeric scaffolds, which is currently regarded as an ideal approach to enhance functional tissue regeneration by creating and maintaining channels that facilitate progenitor cell migration, proliferation and differentiation. The requirements that must be satisfied by such scaffolds include providing a space with the proper size, shape and porosity for tissue development and permitting cells from the surrounding tissue to migrate into the matrix. Recently, chitin scaffolds have been widely used in tissue engineering due to their non-toxic, biodegradable and biocompatible nature. The advantage of chitin as a tissue engineering biomaterial lies in that it can be easily processed into gel and scaffold forms for a variety of biomedical applications. Moreover, chitin has been shown to enhance some biological activities such as immunological, antibacterial, drug delivery and have been shown to promote better healing at a faster rate and exhibit greater compatibility with humans. This review provides an overview of the current status of tissue engineering/regenerative medicine research using chitin scaffolds for bone, cartilage and wound healing applications. We also outline the key challenges in this field and the most likely directions for future development and we hope that this review will be helpful to the researchers working in the field of tissue engineering and regenerative medicine

In Vivo Imaging of Transiently Transgenized Mice with a Bovine Interleukin 8 (CXCL8) Promoter/Luciferase Reporter Construct

One of the most remarkable properties of interleukin 8 (CXCL8/IL-8), a chemokine with known additional functions also in angiogenesis and tissue remodeling, is the variation of its expression levels. In healthy tissues, IL-8 is barely detectable, but it is rapidly induced by several folds in response to proinflammatory cytokines, bacterial or viral products, and cellular stress. Although mouse cells do not bear a clear homologous IL-8 gene, the murine transcriptional apparatus may well be capable of activating or repressing a heterologous IL-8 gene promoter driving a reporter gene. In order to induce a transient transgenic expression, mice were systemically injected with a bovine IL-8 promoter–luciferase construct. Subsequently mice were monitored for luciferase expression in the lung by in vivo bioluminescent image analysis over an extended period of time (up to 60 days). We demonstrate that the bovine IL-8 promoter–luciferase construct is transiently and robustly activated 3–5 hours after LPS and TNF-α instillation into the lung, peaking at 35 days after construct delivery. Bovine IL-8 promoter–luciferase activation correlates with white blood cell and neutrophil infiltration into the lung. This study demonstrates that a small experimental rodent model can be utilized for non-invasively monitoring, through a reporter gene system, the activation of an IL-8 promoter region derived from a larger size animal (bovine). This proof of principle study has the potential to be utilized also for studying primate IL-8 promoter regions

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals &lt;1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Heat exchanger fouling of some Canadian crude oils

Fouling refers to deposition of any kind of extraneous material that appears on the surface of process equipment, such as heat exchangers and reactors. This is a major economic penalty to oil refineries and heavy residuum upgrading units, thus creating incentives for a better understanding of fouling mechanisms which underlie methods to mitigate or control fouling. This research was focussed on a comparative study of the fouling tendencies of three sour crude oils supplied by Shell Canada Limited: Light Sour Blend (LSB), Midale (MDL), and Cold Lake (CLK). The experiments were carried out using a re-circulation fouling loop equipped with an HTRI-type annular electrical probe. Fluids were re-circulated for a 48 hour period from a feed tank, through the annular fouling probe, and back to the tank. The unit was operated at a constant heat flux with time, so that fouling could be tracked by the increase in surface temperature of the probe. Velocity was held constant at 0.75 m/s in most experiments. The unit was pressurized to 860-1240 kPa, depending on the oil used. Bulk temperatures were varied over the range 200-280°C, and surface temperatures covered the range 330-380°C. The decrease in overall heat transfer coefficient varied from 3% to 60%, with most results being in the range 10-32%, depending on conditions. Fouling resistances up to 0.3 m²K/kW were recorded. The effects of various parameters, namely surface temperature, bulk temperature, film temperatures, and annular velocities, on fouling rates were studied for Light Sour blend in detail. When correlating temperature effects on fouling rates, some authors use the surface temperature, while others use the average film temperature, Tf = 0.5 (Ts + T b). In this study both were examined. A slightly modified film temperature, which gave more weight to the surface temperature, was found to be the best. Deposits carefully recovered from the HTRJ probe, after each experiment, were analyzed using energy dispersive x-ray, giving point analyses on the deposit surface, and by micro elemental analysis for bulk content of C, H, S and N. Thermogravimetry was used to determine bulk ash content.Applied Science, Faculty ofChemical and Biological Engineering, Department ofGraduat

Geochemical, Sr and Nd isotopic studies on the Kalva Rangan Durga Quartzites of the Shimoga greenstone belt: Implications on weathering of Dharwarian continental crust

The Mesoarchean Kalva Rangan Durga Formation of the Shimoga greenstone belt in the western Dharwar Craton consists of orthoquartzite, ferruginous phyllite, banded ferruginous chert, and conglomerates. Thick beds of orthoquartzites of this formation are well exposed in Kalva Rangan Durga ridge, trending northeast to southwest for about 9 km, in the southwest part of the Honnali Dome. Quartzites are fine-grained in nature and mostly composed of quartz grains and fuchsite mica. In the present study, we have collected quartzite samples and carried out geochemical, Sr, and Nd isotope analyses to decipher their paleo-weathering conditions, provenance characteristics, and possible tectonic setting of deposition. Geochemical data indicate they are arkose to subarkose in nature. Moderate to intense chemical weathering of the source rocks of these quartzites during the Mesoarchean is suggested based on various weathering indices and ternary plots. Enriched LREE and flat to variably fractionated HREE patterns with negative Eu anomalies of quartzites indicate that they were mainly derived by weathering of tonalities, trondhjemite, and granodiorites (TTG) gneisses and granites. The relatively high concentration of Cr with variable Th/Sc and high Cr/Th ratios indicate both felsic and mafic sources for quartzites. Initial εNd values (t = 3.0 Ga) of quartzites range from −3.04 to +1.24 which further support their derivation from both older evolved continental crustal and juvenile sources. The presence of symmetrical ripple marks on the surface of quartzite indicates a shallow marine environment

Linear Free Energy Relationship in Naphthalene System-Substituent Effects on Carbon-13 Chemical Shifts of Substituted Naphthyl Methyl Sulphides

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Cancer Therapeutic Proficiency of Dual-Targeted Mesoporous Silica Nanocomposite Endorses Combination Drug Delivery

The cargo-loaded mesoporous silica nanoparticles (MSNs) with convenient surface modification can facilitate the development of the innovative nanodrug system. Herein, the present investigation described the electrostatically self-assembled MSNs as a nanosized drug carrier to realize potent synergistic chemotherapy based on the specificity in targeting cytoplasm and nucleus of tumor cells. In this context, the primarily constructed MSNs were subjected with anticancer drug topotecan (TPT) into its large pores. Then, the selective TAT peptide (a nuclear localization signal peptide) was anchored onto TPT-loaded MSNs (TPT-MSN). Subsequently, the positive surface of TPT-MSN-TAT was capped with negatively charged components, poly­(acrylic acid) (PAA)-cRGD peptide and citraconic anhydride (CAH)-metformin (MT), and acted as a smart gatekeeper. Comparatively, PAA-cRGD attached onto MSNs serving as the targeted molecules could upsurge by invasion into cancer cells. Interestingly, the acidic pH of the lysosomal compartment in tumor cells triggers the conjugated CAH from the polymer decorated mesoporous silica (PMS) nanocomposite and could efficiently release MT into the cytoplasm. Consequently, the remaining TPT-MSN-TAT efficiently targets the nucleus and delivers the TPT to improve synergistic chemotherapeutic effects. The precisely released drugs were individually enhanced in the <i>in vitro</i> and <i>in vivo</i> cell killing efficiencies. Thus, the study provides a potential drug delivery podium through combined drugs to realize cancer cell targeting approach