Defect minimization and feature control in electrospinning through design of experiments

Electrospinning is affected by high variability, and an accurate setting of process parameters is fundamental for producing high quality nanofibers. This work aims at determining the optimal values of the main process parameters (polymer concentration, polymer feed rate, and voltage) as a function of the environmental factors (temperature and humidity), in order to obtain nanofibrous materials within a specific range of fiber diameter and porosity, and at the same time to minimize production defects. The response surfaces of diameter, porosity, and defects are first determined with a central composite design. These surfaces are then employed as an input for the optimization problem: diameter and porosity surfaces are used to constrain an admissible region, where the minimum of the defect surface is searched. The approach is tested on a prototype electrospinning machine. The estimated response surfaces capture the variability of the process with respect to both production parameters and environmental factors, and are capable of getting the optimal values of the process parameters. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44740.     

Exogenous opioid peptides derived from food proteins and their possible uses as dietary supplements: A critical review

Endogenous opioid peptides are neuro-hormones and neurotransmitters involved in several physiological actions such as stress reactions, nociception control, sedation, breathing tone, depression, hypotension, appetite, digestion, etc. It is now clear that hydrolysis by the digestion of certain food-proteins can lead to the production of bioactive peptides. Commonly diffused foods like milk, wheat, meat, and spinach may produce after enzymatic digestion a variable amount of opioid peptides. The aim of this review is to provide arising perspectives on opioid peptides, focusing on their production from milk, their potential benefits, drawbacks, and safety issues related to infants’ feeding.     

Nutraceutical value and toxicological profile of selected red wines from Morocco

The polyphenolic composition, antioxidant properties and multielement profile of selected red wines from Morocco were evaluated. The polyphenolic contents resulted higher than those reported elsewhere for the same variety of wines; the highest quantity was found in Cabernet Sauvignon, followed by Merlot, and last by Syrah wine. All of the wines tested showed very similar anthocyanin and flavonol patterns: individual compound contents resulted generally higher in comparison to conventional wines. The content of trans-resveratrol was significantly higher than that of cis-resveratrol in all of the wine samples. Particularly, Merlot showed the highest concentration of trans-resveratrol while Syrah exhibited the highest levels of cis-resveratrol. Reducing capacity resulted higher than antiradical property for all of the wines. The metal concentrations were below the official limits. The elemental pattern of wines were very similar, excepted V, Mn, Fe, Cu, As and Mo, for which Syrah markedly differed from the other wine samples.     

Antibiotics in the environment: occurrence in Italian STPs, fate, and preliminary assessment on algal toxicity of amoxicillin

Amoxicillin is a widely used penicillin-like antibiotic, and due to its presence in several effluents of Italian STPs, its environmental fate along with its toxicity toward simple organisms have been investigated in model conditions. The present study shows that under abiotic conditions both hydrolysis and direct photolysis could be responsible for the transformation and removal of amoxicillin in aquatic environment, especially in slightly basic media. Quantum yields for the solar direct photolysis have been calculated along with kinetic constants and half-life times. Indirect photolysis experiments in the presence of natural photosensitizers such as nitrate ions and humic acids indicate that nitrate ions have no influence on the photodegradation rate of amoxicillin, while humic acids are able to enhance it. Standard batch experiments have been also performed under biotic conditions. The results indicated that also biodegradation on activated sludge is an effective pathway through which amoxicillin can be removed from the aquatic environment. Rate constants for biodegradation and adsorption have been calculated by applying simple pseudo-first-order kinetic models. Algal bioassays indicate that, in the range of concentrations from 50 ng/L to 50 mg/L, amoxicillin is not toxic toward eucariotic organisms such as the Chlorophyceae Pseudokirkneriella subcapitata and Closterium ehrenbergii and the Bacillariophyceae Cyclotella meneghiniana, but it shows a marked toxicity toward the Cyanophyta Synechococcus leopolensis.     

基于3D Si PIN阵列热中子探测器的变增益宽动态前端读出电子学设计

基于Si CMOS技术的前端读出ASIC主要是根据3D Si PIN阵列热中子探测器的输出信号特性设计的。所设计的读出ASIC的主要电路模块包括电荷灵敏放大器（CSA）、模拟开关设计、具有三级电荷灵敏自动转换的自动增益控制模块（AGC）、相关双采样（CDS）和基准电流源电路。仿真结果表明,前端电路的输入动态范围为10 fC~80 pC。根据热中子探测器输出信号特性设计的ASIC的3个增益系数分别为19 V/pC、039 V/pC和94 mV/pC。所设计的ASIC的积分非线性小于 1%。单通道静态功耗约为 536 mW。零输入探测器电容时的等效噪声电荷为2416e-。计数率可达1 MHz 。     

Ultra-thin films based on random copolymers containing perfluoropolyether side chains

Random copolymers were synthesised by copolymerizing methylmethacrylate and perfluoropolyetherurethanemethacrylate monomers, differing for the structural unit of the fluorinated chain, its end group and its molecular weight. The copolymers obtained had similar molecular weight and polydispersity, with a fluorine content between 5 and 10% wt/wt; they showed remarkable features such as biphasicity with coexistence of soft domains made of the perfluoropolyether chains and hard domains due to the methylmethacrylate backbone: the glass transition temperature T_g of the soft and hard phases was T_g1 < 90 °C and T_g2 ≅ 110 °C respectively. All the copolymers were highly hydrophobic: water contact angle was always higher than 105°. The copolymers were used for the preparation of ultra thin films by spin coatings: by atomic force microscopy and X-ray reflectivity the thickness was found in the range of 20-400 Å depending on the spinning conditions, in particular the concentration of the spun solutions. The films were also highly smooth, with a roughness lower than 5 Å.     

Rapid Screening of Antioxidant Anthocyanins in Autochthonous Nero d’Avola Grape Clones by Pre-column DPPH Reaction Coupled to UHPLC-UV/Vis-IT-TOF: a Strategy to Combine Chemical data and Genetic Diversity

Grape is a rich source of bioactive compounds; among them anthocyanins are associated to many healthy properties, possessing a good antioxidant activity. In this work, we developed a fast and simple screening of antioxidant anthocyanins in six Sicilian Nero d’Avola autochthonous grape clones. The method was based on the pre-column reaction with 2,2′-diphenyl-1-picrylhydrazyl radical followed by the rapid separation by ultra high-pressure liquid chromatography coupled with ultraviolet and tandem mass spectrometry detection. Peak areas of antioxidant anthocyanins significantly reduced or even disappeared. The entire method took only 45 min per sample, showing good retention time and peak area repeatability with maximum CV% values ≤0.86 and 6.84, respectively. Samples rich in delphinidin derivatives showed lowest IC₅₀ values, since those compounds possess the highest scavenging ability. The developed setup was less complex than online approaches and faster with respect to conventional high-performance liquid chromatography methods, taking advantage of ultra high-performance conditions, coupled for the first time with pre-column 2,2′-diphenyl-1-picrylhydrazyl assay. The proposed strategy is a valid tool for a rapid screening of antioxidant anthocyanins in grape samples, useful to correlate the genetic diversity with the production of secondary metabolites as well to assess their activity in nutraceutical products rich in anthocyanins.     

Transparent diamond microelectrodes for biochemical application

In this investigation a technology has been developed to use diamond electrodes in Micro Electrode Arrays (MEAs) on a transparent sapphire substrate, thus combining the outstanding electrochemical properties of boron-doped diamond electrodes (BDD) with the transparency needed for simultaneous fluorescence analysis. Nanodiamond films were grown on double side polished sapphire substrates by hot filament CVD (HFCVD) and Bias Enhanced Nucleation (BEN). A simple four microelectrode array (quadrupole) has been fabricated, fully characterized in optical and electrochemical properties, and tested with adrenal chromaffin cells, identifying amperometric spikes by the four recording diamond electrodes, corresponding to the oxidation current of catecholamine molecules.     

Controlled variation of the refractive index in ion-damaged diamond

A fine control of the variation of the refractive index as a function of structural damage is essential in the fabrication of diamond-based optical and photonic devices. We report here about the variation of the real part of the refractive index at λ = 632.8 nm in high-quality single-crystal diamond damaged with 2 and 3 MeV protons at low-medium fluences (10¹³–10¹⁷ ions cm^? 2). After implanting the samples in 125 × 125 μm² areas with a raster scanning ion microbeam, the variation of optical thickness of the implanted regions was measured with laser interferometric microscopy. The results were analyzed with a model based on the specific damage profile. The technique allows the direct fabrication of optical structures in bulk diamond based on the localized variation of the refractive index, which will be explored in future works.