Rheological and fusion behaviors of PVC micro‐ and nano‐composites evaluated from torque rheometer data

The effects of calcium carbonate (CaCO₃) particle size on the fusion and rheological behaviors of rigid poly(vinyl chloride) (PVC) composites prepared in a Haake torque rheometer were investigated by means of torque data recorded during processing. Increasing the number of particles in the same blend volume by decreasing the particle size resulted in increasing frictional forces. This increase led in turn to increased fusion torque and decreased fusion time and temperature. The power‐law‐index values of the composites increased with decreasing particle size except for 25‐nm CaCO₃. The viscosities of all composites were found to decrease with shear rate; therefore, high pseudoplasticity was observed. At a particular rotor speed, viscosity of the composites decreased with decreasing particle size except for 25‐nm CaCO₃. The overall results showed that the particle size of CaCO₃ altered the fusion characteristics and rheological behavior of PVC. J. VINYL ADDIT. TECHNOL., 2010. © 2010 Society of Plastics Engineers     

3‐Heterocycle‐Phenyl N‐Alkylcarbamates as FAAH Inhibitors: Design,Synthesis and 3D‐QSAR Studies

Carbamates are a well‐established class of fatty acid amide hydrolase (FAAH) inhibitors. Here we describe the synthesis of meta‐substituted phenolic N‐alkyl/aryl carbamates and their in vitro FAAH inhibitory activities. The most potent compound, 3‐(oxazol‐2yl)phenyl cyclohexylcarbamate ( 2 a ), inhibited FAAH with a sub‐nanomolar IC₅₀ value (IC₅₀=0.74 nM ). Additionally, we developed and validated three‐dimensional quantitative structure–activity relationships (QSAR) models of FAAH inhibition combining the newly disclosed carbamates with our previously published inhibitors to give a total set of 99 compounds. Prior to 3D‐QSAR modeling, the degree of correlation between FAAH inhibition and in silico reactivity was also established. Both 3D‐QSAR methods used, CoMSIA and GRID/GOLPE, produced statistically significant models with coefficient of correlation for external prediction (R²_PRED) values of 0.732 and 0.760, respectively. These models could be of high value in further FAAH inhibitor design.     

Extracellular Vesicles Taken up by Astrocytes

Extracellular vesicles (EVs) are composed of lipid bilayer membranes and contain various molecules, such as mRNA and microRNA (miRNA), that regulate the functions of the recipient cell. Recent studies have reported the importance of EV-mediated intercellular communication in the brain. The brain contains several types of cells, including neurons and glial cells. Among them, astrocytes are the most abundant glial cells in the mammalian brain and play a wide range of roles, from structural maintenance of the brain to regulation of neurotransmission. Furthermore, since astrocytes can take up EVs, it is possible that EVs originating from inside and outside the brain affect astrocyte function, which in turn affects brain function. However, it has not been fully clarified whether the specific targeting mechanism of EVs to astrocytes as recipient cells exists. In recent years, EVs have attracted attention as a cell-targeted therapeutic approach in various organs, and elucidation of the targeting mechanism of EVs to astrocytes may pave the way for new therapies for brain diseases. In this review, we focus on EVs in the brain that affect astrocyte function and discuss the targeting mechanism of EVs to astrocytes.     

Simulation of vacuum distillation to produce alcohol-free beer

Several processes have been developed for producing alcohol-free beer while maintaining desirable sensory characteristics. One of the most popular thermal processes used is distillation, where not only ethanol but volatile aromatic components are partly or completely removed from the beer. Based on data from the literature and using the Aspen Plus simulator, this study evaluates and compares the aroma profiles of alcohol-free beers obtained by continuous vacuum distillation with different pressures and processes. Three processes were simulated at pressures of 60, 102, and 200 mbar. The first (Process A) was a standard continuous vacuum distillation, where the bottom product was an alcohol-free beer. In the second (Process B), the bottom product was blended with a standard beer that had not undergone any thermal process. In the third (Process C), part of the top stream was mixed with the bottom product. This study considered eight major compounds in beer: ethanol, propanol, isobutanol, 2-methyl-1-butanol, 3-methyl-1-butanol, ethyl acetate, diacetyl and isoamyl acetate. The three simulated pressure ranges showed similar results, indicating that reducing the pressure below 200 mbar did not improve separation. Further, vacuum distillation did not remove diacetyl from the beer. Processes B and C resulted in beer that was richer in flavour compounds. Furthermore, when these processes were compared to Process A, the concentration of esters was markedly higher. © 2019 The Institute of Brewing & Distilling     

Vitamins in brewing: effects of post‐fermentation treatments and exposure and maturation on the thiamine and riboflavin vitamer content of beer

Post‐fermentation processes and maturation are important steps in beer production as they help to shape the organoleptic properties and stabilize the final product. Brewers can use a variety of processing aids (e.g. isinglass, PVPP, etc.) and processes (e.g. pasteurization, bottle conditioning, etc.) to achieve a desired final product with a desirable shelf life; however, these processes can have detrimental effects on the vitamin content of the beer. This research found that heat treatments have a marked influence on the decrease in the thiamine diphosphate vitamer, while PVPP and silica treatments have a greater influence on the decrease in riboflavin vitamers. Refrigeration, filtration or centrifugation have no, or only very limited, influence on thiamine or riboflavin vitamers, while application of isinglass, bentonite, tannic acid and SO₂ causes a decrease in both thiamine and riboflavin vitamers. Storage of beer at refrigerated temperatures appears to provide protection against significant degradation of both thiamine and riboflavin vitamers; however, storage of filtered beer at elevated temperatures shows a decrease in thiamine diphosphate and riboflavin. Storage of bottle‐conditioned beer at elevated temperatures shows a marked decrease in yeast viability, accompanied by a decrease in thiamine diphosphate and free riboflavin, and a marked increase in free thiamine. These findings provide an insight into the reason why there is a significant variation in the vitamer content of beers, even within a single beer style. Copyright © 2016 The Institute of Brewing & Distilling     

Search for Superconductivity in Lithium

We report on the results of a search for superconductivity in Li. We find no evidence for the predicted transition to superconductivity at any temperature down to 5 mK in magnetic fields down to 0.4 T. However, an unexpected Curie–Weiss temperature dependence in the magnetic susceptibility is observed. We discuss the possibility that this signal arises from the Li itself, the possibility that it arises from Kondo behavior, and the implications of the effect for the predicted T_c of Li.     

Prediction of Residual Stresses Using Partial Least Squares Regression on Barkhausen Noise Signals

Residual stresses are quantitatively predicted based on the Barkhausen noise measurement with a partial least squares regression model. The measurements are taken from two sets of case-hardened samples. The benefits of using certain feature elimination strategies prior model identification are also studied. The elimination methods applied are correlation-based elimination, uninformative variable elimination and successive projections algorithm. The results show that the best predictions are usually obtained when the successive projections algorithm is applied. The prediction accuracy of the best models found shows that partial least squares models can be successfully used for prediction of material properties based on the Barkhausen noise measurement.     

Design,preparation, and characterization of new high-refractive index hybrid organic–inorganic polysiloxanes: Innovative coatings for optoelectronic applications

The current demand for high-refractive index materials is very high due to their importance in optoelectronic applications. Such materials already exist in the market, but they present many disadvantages. They might contain toxic metals; their preparation can be challenging or produce high quantity of waste. Consequently, there is an urgent need to produce new friendly coatings with high-refractive index. Hybrid organic–inorganic polysiloxanes can offer a solution to this problem. They can be easily prepared from nontoxic alkoxy silanes using the sol–gel chemistry process. Herein, a series of new hybrid polysiloxanes are synthesized from the monomer 1–(2–(triethoxysilyl)ethyl)triphenylsilane and other silanes. The preparation of the macromolecules is optimized at both stages of the sol–gel process. The polymers are characterized by gel permeation chromatography and NMR spectroscopy. Spin coating of the materials on silicon wafers, followed by film thickness and refractive index measurements, indicates that the new polysiloxanes can have refractive indexes as high as 1.6 with thicknesses varying from 2200 to 3700 nm. Consequently, it is expected that the new materials described in this report are valuable for optoelectronic applications such as high-dielectric constant (high-k) gate oxides, interlayer high-k dielectrics, or high-refractive index abrasion resistant coatings.     

Design,synthesis, characterization,and aging properties of a new end-capped three-dimensional high-refractive index hybrid organic–inorganic polysiloxane

The actual need for hybrid organic–inorganic polysiloxanes is very high due to their importance in optoelectronic applications, especially for the preparation of anti- and low-reflection layers, photopatterned overcoats, flexible hard coats, and glass and metal coatings. However, such three-dimensional hybrid polysiloxanes have very often a limited shelf life and aged very rapidly. Consequently, this type of polymer may require to be stored at cold temperatures and needs to be dilute in organic solvent to a very low solid content, which are unprofitable conditions for commercialization purposes. Therefore, there is an urgent demand to prepare three-dimensional polysiloxanes, which are more resistant toward aging processes. Herein, a new hybrid three-dimensional polysiloxane has been designed and synthesized from three different silane precursors using the sol–gel technology, and characterized using gel permeation chromatography, ¹H, ¹³C, and ²⁹Si nuclear magnetic resonance and MS spectroscopies. One-fourth of the silanol groups present in the polysiloxane have been protected with chlorotrimethylsilane. The refractive index of the silicon wafer coated with the new polysiloxane was found to be 1.53, which is higher compare to traditional values. Importantly, the new protected three-dimensional polysiloxane did not age after being stored at T = 40°C for 3 weeks.