Synthesis of high surface area mesoporous silica SBA-15 for hydrogen storage application

In the present report, mesoporous silica SBA-15 was synthesized by different methods such as room temperature aging, hydrothermal, and sonication-mediated hydrothermal methods. The effect of different time and temperature on the synthesis method was investigated by conventional characterization techniques. The powders synthesized by different methods showed different properties, mainly in morphology and pore volume. In comparison to others, the powder synthesized by the hydrothermal method at 100°C for 48 hours showed exceptionally high surface area of 3274 m²/g. To date, as per our knowledge, no such value was reported in literature. Finally, the powders were characterized by H₂ storage capacity by the adsorption-desorption method using 99.999% H₂. The hydrogen adsorption capacity of the same powder was observed at 6.02 wt%. Also, this value seems to be the highest H₂ adsorption capacity in comparison to other powders described in literature.     

Prediction of future world wide web traffic characteristics for capacity planning

To plan for future network capacity requires an understanding of traffic. This article presents a traffic characterization and performance evaluation of future WWW protocols. © 1997 John Wiley & Sons, Ltd.     

Liquid�CLiquid Extraction of Lipase Using Aqueous Two-Phase System

The application of aqueous two-phase extraction for the downstream processing of lipase has been exploited. The influence of system parameters such as phase forming salts, molecular weight of the phase forming polymer, system pH, tie line length, and phase volume ratio on the partitioning behavior of lipase was evaluated. The aqueous two-phase system consisting of PEG6000 and disodium phosphate (Na₂HPO₄) resulted in one-sided partitioning of lipase with partition coefficient 0.11, activity recovery 116%, and purification factor of 2.25. Further, the purity of lipase was increased to 3.59-fold using multi-stage extractions.     

Targeting Cell Cycle Progression in HER2+ Breast Cancer: An Emerging Treatment Opportunity

Layman summaryHER2 is an oncogenic driver in a subset of breast cancer. Despite the fact that there are the options of several anti-HER2 targeted therapies, most patients with metastatic HER2+ breast cancer die from the disease. Therapies to overcome treatment resistance in the metastatic settings (including brain metastasis) are actively being pursued. Recently, cell cycle inhibitors (CDK 4/6 inhibitors) have been approved to manage hormone receptor-positive breast cancer, and have encountered tremendous success. The cell cycle signaling proteins, Cyclin D-CDK4/6, are downstream of HER2 and play a key role in cellular proliferation. Moreover, cell cycle inhibitors have the capacity to cross the blood–brain barrier. Here, we review the published literature with regard to the rationale for CDK4/6-directed therapies in HER2+ breast cancer.AbstractThe development of HER2-targeted therapies has dramatically improved patient survival and patient management and increased the quality of life in the HER2+ breast cancer patient population. Due to the activation of compensatory pathways, patients eventually suffer from resistance to HER2-directed therapies and develop a more aggressive disease phenotype. One of these mechanisms is the crosstalk between ER and HER2 signaling, especially the CDK4/6-Cyclin D-Rb signaling axis that is commonly active and has received attention for its potential role in regulating tumor progression. CDK 4/6 inhibitors interfere with the binding of cell-cycle-dependent kinases (CDKs) with their cognate partner cyclins, and forestall the progression of the cell cycle by preventing Rb phosphorylation and E2F release that consequentially leads to cancer cell senescence. CDK 4/6 inhibitors, namely, palbociclib, ribociclib, and abemaciclib, in combination with anti-estrogen therapies, have shown impressive outcomes in hormonal receptor-positive (HR+) disease and have received approval for this disease context. As an extension of this concept, preclinical/clinical studies incorporating CDK 4/6 inhibitors with HER2-targeted drugs have been evaluated and have shown potency in limiting tumor progression, restoring therapeutic sensitivity, and may improving the management of the disease. Currently, several clinical trials are examining the synergistic effects of CDK 4/6 inhibitors with optimized HER2-directed therapies for the (ER+/-) HER2+ population in the metastatic setting. In this review, we aim to interrogate the burden of HER2+ disease in light of recent treatment progress in the field and examine the clinical benefit of CDK 4/6 inhibitors as a replacement for traditional chemotherapy to improve outcomes in HER2+ breast cancer.     

Extended studies on surface‐treated graphite vis‐à‐vis its application in high alumina refractory castable

This investigation entails our continued research on calcium aluminate coated graphite for application in alumina‐carbon monolithic refractories. Surface treatment of graphite flakes by a scalable sol‐gel route has been utilized to develop stable bonds between ceramic phases with the functionalized graphite sheets. This study has been primarily conducted to differentiate between the coating evolution pattern at green and calcined conditions. In this regard, C‐H‐N analysis, differential scanning calorimetry (DSC), transmission electron microscopy (TEM), x‐ray diffraction (XRD) with Rietveld analysis, Fourier transformed infrared spectroscopy (FTIR) and zeta potential studies of three kinds of graphites had been compared and critically estimated. These results were supplemented with thermogravimetry (TG), pore size distribution, oxidation resistance and scanning electron microscopy (SEM) of selected samples. A schematic outline of the work has also been proposed. An appreciable improvement of bulk density, apparent porosity and crushing strength of the respective castable has been correlated with the compatibility of the coating to the reactive matrix constituents of the refractory in wide temperature region (110‐1500°C).     

Unconventional Biocatalytic Approaches to the Synthesis of Chiral Sulfoxides

Sulfoxides are a class of organic compounds that find wide application in medicinal and organic chemistry. Several biocatalytic approaches have been developed to synthesise enantioenriched sulfoxides, mainly by exploiting oxidative enzymes. Recently, the use of reductive enzymes such as Msr and Dms has emerged as a new, alternative method to obtain enantiopure sulfoxides from racemic mixtures. In parallel, novel oxidative approaches, employing nonclassical solvents such as ionic liquids (ILs) and deep eutectic solvents (DESs), have been developed as greener and more sustainable biocatalytic synthetic pathways. This minireview aims highlights the recent advances made in the biocatalytic synthesis of enantioenriched sulfoxides by employing such unconventional approaches.     

Effect of cellulose buffer layer on synthesis and gas permeation properties of NaA zeolite membrane

NaA zeolite membrane coating was successfully synthesized on a porous alumina substrate by hydrothermal treatment. The effects of synthesis parameters like, seeding type (ex situ, in situ), time, temperature, sol concentration, coating stages, application of intermediate layer, etc. on membrane characteristics were investigated. A continuous membrane was formed on a seeded substrate. Surface seeding (ex situ crystallization) not only accelerates the zeolite crystallization process on the support surface, but can also enhance the formation of homogeneous NaA zeolite layer. The NaA zeolite membrane with a synthesis time of 4 h shows the best microstructure and the quality of membrane was improved by employing the multi-stage coating. But the main problem associated with membrane synthesis was crack formation, and it can be reduced by applying intermediate layer, between support surface and seed layer. A thin cellulose layer was applied to the support surface before applying seed crystals. The performance of the membranes was evaluated by gas permeation measurement. The permeance of O₂, N₂ decreased as kinetic diameter of gases increased. The permselectivity of O₂/N₂ was 1.9–2.34. This value showed the molecular sieving effect of NaA zeolite membrane.     

Performance of zeolite powder and tubular membrane having different Si/Al ratio for removing As(III) in aqueous phase

Three different types of zeolite having pore sizes in the range 0.26‐0.74 nm, (NaP, NaA, and NaY) powders and membranes are synthesized with different Si:Al ratio on low cost clay alumina tubular support. The results of the permeation and separation studies showed that the NaP zeolite powder and membrane removes maximum As(III) from the water solution (more than 80%) compared to other zeolites. The removal of As(III) to achieve drinking water standard, by zeolite membrane, in a single step process does not seem to have been reported before the present investigation. These are the novelty achieved.     

Investigation of influence of medium ph and sulfate ion concentrations on corrosion behavior of magnesium alloy ZE41

Magnesium alloys have emerged as potential structural materials with all capabilities to even replace close contenders; aluminium alloys in weight-critical applications. High susceptibility to corrosion being the only limitation, corrosion of magnesium alloys continues to gather much attention among the material scientists worldwide. ZE41 is one such alloy of magnesium which is increasingly gaining importance as automobile and aerospace material. In the present study the influence of the medium pH and sulfate ion concentrations on the corrosion behavior of magnesium alloy ZE41 has been investigated using electrochemical techniques like the Tafel extrapolation and electrochemical impedance spectroscopy (EIS). The tests have been carried out in a range of conditions, with gradually varying pH and sulfate ion concentration. The morphology and composition of the corroded alloy surface have been determined by the scanning electron microscopy (SEM) and energy dispersion X-ray (EDX) analysis, respectively. The recorded results reflect a trend of a higher corrosion rate associated with a higher sulfate concentration at each pH and with a lower pH at each sulfate concentration.