Chemoenzymatic One‐Pot Synthesis of γ‐Butyrolactones

The synthesis of enantio‐ and diastereomerically pure γ‐butyrolactones is described using a one‐pot, two‐enzyme cascade. Ethyl 2‐methyl‐4‐oxopent‐2‐enoate ( 2 ) was reduced selectively first in a 1,4‐reduction using the old yellow enzyme (OYE1) [EC 1.6.99.1] and consecutively in a 1,2‐reduction by an alcohol dehydrogenase [EC 1.1.1.2].     

Combined Hydrothermal Conversion and Vapor Transport Sintering of Ag‐Modified Calcium Phosphate Scaffolds

Two processing methods were successfully combined to obtain Ag‐modified calcium phosphate scaffolds with antibacterial properties: (i) hydrothermal conversion of macroporous biogenic carbonates and (ii) vapor transport sintering. Hydrothermal conversion of two precursor materials, i.e., coral skeletons and sea urchin spines, resulted in the pseudomorphic replacement of highly porous calcium carbonates by calcium phosphate scaffolds. Vapor transport sintering of these scaffolds within a reactive AgCl atmosphere facilitated near net‐shape processing accompanied by the condensation of finely dispersed Ag‐bearing particles over the scaffold's surface. Chemical and phase compositions were analyzed using WDXRF, XRD, and DRIFTS (FTIR), and the microstructure development was characterized by SEM and TEM imaging. The dissolution kinetics of Ag⁺ ions in aqueous solution was determined and growth inhibition experiments with Gram‐positive and Gram‐negative bacteria were performed to assess the antibacterial properties of Ag‐modified ceramics.     

A geoscience perspective on immersive 3D gridded data visualization

We describe visualization software, Visualizer, that was developed specifically for interactive, visual exploration in immersive virtual reality (VR) environments. Visualizer uses carefully optimized algorithms and data structures to support the high frame rates required for immersion and the real-time feedback required for interactivity. As an application developed for VR from the ground up, Visualizer realizes benefits that usually cannot be achieved by software initially developed for the desktop and later ported to VR. However, Visualizer can also be used on desktop systems (unix/linux-based operating systems including Mac OS X) with a similar level of real-time interactivity, bridging the “software gap” between desktop and VR that has been an obstacle for the adoption of VR methods in the Geosciences. While many of the capabilities of Visualizer are already available in other software packages used in a desktop environment, the features that distinguish Visualizer are: (1) Visualizer can be used in any VR environment including the desktop, GeoWall, or CAVE, (2) in non-desktop environments the user interacts with the data set directly using a wand or other input devices instead of working indirectly via dialog boxes or text input, (3) on the desktop, Visualizer provides real-time interaction with very large data sets that cannot easily be viewed or manipulated in other software packages. Three case studies are presented that illustrate the direct scientific benefits realized by analyzing data or simulation results with Visualizer in a VR environment. We also address some of the main obstacles to widespread use of VR environments in scientific research with a user study that shows Visualizer is easy to learn and to use in a VR environment and can be as effective on desktop systems as native desktop applications.     

Synthesis and self‐assembly study of zwitterionic amphiphilic derivatives of chitosan

New zwitterionic derivatives of chitosan (CH) were synthesized through the Michael addition reaction of 1‐(3‐sulfopropyl)‐2‐vinylpyridine hydroxide (SPP) with primary amines of deacetylated CHs (with weight‐average molecular weights of 46 and 216 kDa) to obtain SPP‐substituted CHs. The hydrophilic derivatives were subsequently modified with 2.1, 4.6, and 9.7% of dodecyl groups [degree of substitution by dodecyl groups (DS_Dod)]. The SPP‐substituted CH derivatives were characterized by ¹H‐NMR, Fourier transform infrared spectroscopy, and gel permeation chromatography. Aqueous solutions of SPP‐substituted CH samples remained clear, independently of the pH (3.0 < pH < 12.0). The self‐association study of the amphiphilic derivatives was performed in aqueous buffered solution at pH 5.0 and 7.4, and the critical aggregation concentration values varied from 5.6 × 10^?3 to 0.02 g/L. The measurements of dynamic light scattering and ζ potentials showed that the self‐assembly behavior was dependent on the pH and DS_Dod. At pH 7.4, the measured ζ potentials were near zero, and colloidal stability was provided by the hydrated zwitterionic shell of the aggregates. Transmission electron microscopy revealed spherelike microsized particles of broad distribution. The amphiphilic SPP‐substituted CH samples were shown to be nontoxic with a 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assay performed with HeLa cells. The remarkable water solubility and nontoxicity displayed by the new SPP‐substituted CH derivatives showed promising properties for the design of CH‐based biomaterials and nanoparticles. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44176.     

Syngonanthus nitens Bong. (Rhul.)-Loaded Nanostructured System for Vulvovaginal Candidiasis Treatment

Herbal-loaded drug delivery nanotechnological systems have been extensively studied recently. The antimicrobial activity of medicinal plants has shown better pharmacological action when such plants are loaded into a drug delivery system than when they are not loaded. Syngonanthus nitens Bong. (Rhul.) belongs to the Eriocaulaceae family and presents antiulcerogenic, antioxidant, antibacterial, and antifungal activity. The aim of this study was to evaluate the antifungal activity of Syngonanthus nitens (S. nitens) extract that was not loaded (E) or loaded (SE) into a liquid crystal precursor system (S) for the treatment of vulvovaginal candidiasis (VVC) with Candida albicans. The minimal inhibitory concentration (MIC) was determined by the microdilution technique. Additionally, we performed hyphae inhibition and biofilm tests. Finally, experimental candidiasis was evaluated in in vivo models with Wistar female rats. The results showed effective antifungal activity after incorporation into S for all strains tested, with MICs ranging from 31.2 to 62.5 μg/mL. Microscopic observation of SE revealed an absence of filamentous cells 24 h of exposure to a concentration of 31.2 μg/mL. E demonstrated no effective action against biofilms, though SE showed inhibition against biofilms of all strains. In the in vivo experiment, SE was effective in the treatment of infection after only two days of treatment and was more effective than E and amphotericin B. The S. nitens is active against Candida albicans (C. albicans) and the antifungal potential is being enhanced after incorporation into liquid crystal precursor systems (LCPS). These findings represent a promising application of SE in the treatment of VVC.     

Endothelial Lipase Modulates Paraoxonase 1 Content and Arylesterase Activity of HDL

Endothelial lipase (EL) is a strong modulator of the high-density lipoprotein (HDL) structure, composition, and function. Here, we examined the impact of EL on HDL paraoxonase 1 (PON1) content and arylesterase (AE) activity in vitro and in vivo. The incubation of HDL with EL-overexpressing HepG2 cells decreased HDL size, PON1 content, and AE activity. The EL modification of HDL did not diminish the capacity of HDL to associate with PON1 when EL-modified HDL was incubated with PON1-overexpressing cells. The overexpression of EL in mice significantly decreased HDL serum levels but unexpectedly increased HDL PON1 content and HDL AE activity. Enzymatically inactive EL had no effect on the PON1 content of HDL in mice. In healthy subjects, EL serum levels were not significantly correlated with HDL levels. However, HDL PON1 content was positively associated with EL serum levels. The EL-induced changes in the HDL-lipid composition were not linked to the HDL PON1 content. We conclude that primarily, the interaction of enzymatically active EL with HDL, rather than EL-induced alterations in HDL size and composition, causes PON1 displacement from HDL in vitro. In vivo, the EL-mediated reduction of HDL serum levels and the consequently increased PON1-to-HDL ratio in serum increase HDL PON1 content and AE activity in mice. In humans, additional mechanisms appear to underlie the association of EL serum levels and HDL PON1 content.     

Effect of enzymatic treatment on the cross-flow microfiltration of açaí pulp: Analysis of the fouling and recovery of phytochemicals

This study aimed to investigate the effects of pectinase enzyme treatment of açaí pulp on cross-flow microfiltration (CFMF) performance and on phytochemical and functional characteristics of their compounds. Analyses of fouling mechanisms were carried out through resistance in series and blocking in law models.     

Contents of polycyclic aromatic hydrocarbons (PAH) and phenolic substances in Frankfurter-type sausages depending on smoking conditions using glow smoke

The contents of polycyclic aromatic hydrocarbons (PAH) and phenolic substances in Frankfurter-type sausages were investigated depending on hot smoking conditions (glow smoke). For the 24 smoking experiments (performed in duplicates) three different smoke densities and ventilator velocities as well as wood chips with five different moisture contents were tested. During the smoking process, concentrations of O₂, CO₂ and CO, humidity and temperature in the smoking chamber as well as smoke generation temperature were determined. The chemical analysis included the contents of the 15 + 1 EU priority PAH and the phenolic substances guaiacol, 4-methylguaiacol, syringol, eugenol and trans-isoeugenol. The smoking conditions had a significant influence on smoke generation temperature, organoleptic properties and the formation of PAH and phenolic substances. The PAH contents increased with smoke density and ventilator velocity. No correlation between the contents of PAH and phenols was observed.     

3D互连中光刻与晶圆级键合技术面临的挑战,趋势及解决方案(英文)

目前,3D集成技术的优势正在扩展消费类电子产品的潜在应用进入批量市场。这些新技术也在推进着当前许多生产工艺中的一些封装技术包括光刻和晶圆键合成为可能。其中还需要涂胶,作图和蚀刻结构。探讨一些与三维互连相关的光刻技术的挑战。用于三维封装的晶圆键合技术将结合这些挑战和可用的解决方案及发展趋势一并介绍。此外还介绍了一种新的光刻设备,它可通过图形识别技术的辅助实现低于0.25μm的最终对准精度。对于采用光刻和晶圆级键合技术在三维互连中的挑战,趋势和解决方案及SUSS公司设备平台的整体介绍将根据工艺要求来描述。在这些技术中遇到的工艺问题将集中在晶圆键合和光刻工序方面重点讨论。