Nonlinear evolution of thin liquid films dewetting near soft elastomeric layers

The nonlinear evolution of thin liquid films dewetting near soft elastomeric layers is examined in this work. Evolution equations are derived by applying the lubrication approximation and assuming that van der Waals forces in the liquid cause the dewetting and that the solid can be described as a linear viscoelastic material. Two cases are examined: (i) a liquid layer resting on an elastomer bounded from below by a rigid substrate, and (ii) an elastomer overlying a thin liquid film bounded from below by a rigid substrate. Linear stability analysis is carried out to obtain asymptotic relations which are then compared against solutions of the full characteristic equations. In the liquid-on-solid case, numerical solutions of the evolution equations show that van der Waals forces cause thinning of the liquid film and thickening of the elastomeric solid beneath film depressions. Inclusion of a short-range repulsive force suggests that regular patterns may form in which ridges of fluid rest on depressions in the solid. In the solid-on-liquid case, the van der Waals forces cause the solid layer to break up before the liquid film can dewet. The results presented here support the idea that the dewetting of thin liquid films might be exploited to create topographically patterned surfaces on soft polymeric solids.     

Phenethyl Ester of Gallic Acid Ameliorates Experimental Autoimmune Encephalomyelitis

Gallic acid is a phenolic acid present in various plants, nuts, and fruits. It is well known for its anti-oxidative and anti-inflammatory properties. The phenethyl ester of gallic acid (PEGA) was synthesized with the aim of increasing the bioavailability of gallic acid, and thus its pharmacological potential. Here, the effects of PEGA on encephalitogenic cells were examined, and PEGA was found to modulate the inflammatory activities of T cells and macrophages/microglia. Specifically, PEGA reduced the release of interleukin (IL)-17 and interferon (IFN)-γ from T cells, as well as NO, and IL-6 from macrophages/microglia. Importantly, PEGA ameliorated experimental autoimmune encephalomyelitis, an animal model of chronic inflammatory disease of the central nervous system (CNS)—multiple sclerosis. Thus, PEGA is a potent anti-inflammatory compound with a perspective to be further explored in the context of CNS autoimmunity and other chronic inflammatory disorders.     

Rational Design and Synthesis of AT1R Antagonists

Hypertension is one of the most common diseases nowadays and is still the major cause of premature death despite of the continuous discovery of novel therapeutics. The discovery of the Renin Angiotensin System (RAS) unveiled a path to develop efficient drugs to fruitfully combat hypertension. Several compounds that prevent the Angiotensin II hormone from binding and activating the AT1R, named sartans, have been developed. Herein, we report a comprehensive review of the synthetic paths followed for the development of different sartans since the discovery of the first sartan, Losartan.     

Novel disposable bismuth-sputtered electrodes for the determination of trace metals by stripping voltammetry

This work describes a novel type of bismuth electrode for stripping voltammetry based on coating a silicon substrate with a thin bismuth film by means of sputtering. The bismuth-based sensors were characterized by optical methods (scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray diffraction (XRD)) and as well as by linear sweep voltammetry. Subsequently, the electrodes were tested for the detection of low concentrations of trace metals (Cd(II), Pb(II) and Ni(II)) by stripping voltammetry. Well-formed stripping peaks were observed for trace concentrations of the target analytes demonstrating “proof-of-principle” for these sensors. This type of electrochemical device, utilizing thin-film technology for the formation of the bismuth film, holds promise for future applications in trace metal analysis.     

Current trends in green sample preparation before liquid chromatographic bioanalysis

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Programmable imaging with two-axis micromirrors

We demonstrate a means of creating a digital image by using a two-axis tilt micromirror to scan a scene. For each different orientation we extract a single gray scale value from the mirror and combine them to form a single composite image. This allows one to choose the distribution of the samples, and so in principle a variable resolution image could be created. We demonstrate this ability to control resolution and projection by constructing a voltage table that compensates for the nonlinear response of the mirrors to the applied voltage.     

Novel disposable microfabricated antimony-film electrodes for adsorptive stripping analysis of trace Ni(II)

This work describes a novel type of antimony electrode for adsorptive stripping voltammetry (AdSV). The electrode was microfabricated by coating a silicon chip with a thin antimony-film by means of sputtering and the active area of the electrode was defined by photolithography. The resulting antimony-film electrodes (SbFEs) were characterized by optical and electrochemical techniques. The sensors were tested for the detection of low concentrations of Ni(II) by AdSV in the presence of dimethylglyoxime. Well-formed stripping peaks and a linear dependence of the stripping peak current on the Ni(II) concentration were observed on the microfabricated SbFEs while comparative measurements attempted with electroplated SbFEs were unsuccessful. Utilizing thin-film technology for the formation of the antimony-film extends the scope of these devices as mercury-free sensors in AdSV.     

Connecting Linear Polymers Molecular Structure to Viscoelastic Properties and Melt Flow Index

A modeling pathway and software tool for linking entangled linear polymer molecular properties to linear viscoelasticity and melt index (MI) values is presented. A reptation model links molecular properties to the flow curve, and then, an ANSYS Polyflow model calculates MI values based on the flow curve predicted. The method is thoroughly tested and validated for uni‐ and bimodal, low‐ and high‐density polyethylene grades. An overall accuracy level in the range of 90% on average is exhibited, considering both model prediction steps: (i) molecular weight distribution to flow curve and (ii) flow curve to MI.

     

Über den Verteilungssatz der Auxochrome bei Azokörpern,I. Di- und Tetramethoxy-xobenzole

The validity of the rule of repartition of the auxochromes is examined for some symmetric tetramethoxy-azobenzenes, dimethoxy-azobenzenes, and dimethoxy-4′-nitro-azobenzenes whose methoxy groups are in 2,4-, 3,4- and 2,5-position. The rule is confirmed with 2,4-and 2,5-derivatives. The long wave lengths absorption maxima of 3,4,3′,4′-tetramethoxy-azobenzene and of 3,4-dimethoxy-4′-nitro-azobenzene are situated at shorter wave lengths than expected.