Novel semi-interpenetrating network hydrogels based on monosaccharide oligomers with itaconic moiety: synthesis and properties

Hydrogel-based drug delivery systems encounter great scientific attention nowadays. Semi-interpenetrating network systems with hydrogel features have been studied as potential drug carriers due to their water intake capacity, biocompatibility and biodegradability. One of the most important features of drug delivery systems is biocompatibility and as such materials derived from natural resources seem to be more appropriate to act as excipients. In this respect, two new semi-interpenetrating networks (semi-IPNs) with hydrogel features based on chitosan, two novel oligomers derived from monosaccharides and 2-hydroxyethylmethacrylate (HEMA) have been synthesized and characterized using FTIR, thermogravimetry, SEM/EDX and swelling behavior. The new sugar-derived oligomers (GI and MI) with double bonds available for further polymerization were obtained by polycondensation of 1,3-propanediol with dicarboxylic acids derived from glucose/mannose skeleton with itaconic anhydride moieties. GI and MI oligomers were characterized by FTIR, NMR spectroscopy and ESI–MS spectrometry, which showed molecular weights of about 7000 Da and linear polymerization chain structure. The new semi-IPNs show good thermal behavior and these hydrogels display a swelling tendency by loading significantly more water in an acid environment than in a neutral solution. Moreover, these superabsorbent hydrogels are able to load significant amount of hydrosoluble active principle (herein the antibiotic levofloxacin) and their releasing profile is marked by an important “burst effect”.     

面向油田领域的中文真词错误自动校对方法研究

中文真词错误自动校对是自然语言理解的一项重要的基础研究课题,油田数字化过程中利用图像识别及人工录入产生的中文真词错误会直接影响后期数据综合分析准确度。对中文真词错误成因和统计语言模型进行分析,提出一种面向油田领域的中文真词错误自动校对方法。该方法首先构建通用领域和油田领域混淆集,再引入同义词集丰富知识库,对语料分词后,综合统计分析目标词与混淆词、周边词的同义词之间关系,自动校对真词错误。实验表明,提出的方法能有效校对油田领域的中文真词错误。     

Biomass electrochemistry: Anodic oxidation of an organo-solv lignin in the presence of nitroaromatics

The temperature required for the anodic conversion of an organo-solv spruce lignin, in aqueous alkaline solution, may be lowered by the addition of nitrobenzene or 1,3-dinitrobenzene. The additives cause significant and reproducible changes in the Tafel plot for the reaction. Preparativescale experiments are less reproducible although the range of phenolic products is generally similar to that produced by conventional nitrobenzene oxidation or by anodic oxidation at higher temperatures.     

On the design of hybrid bio-inspired meta-heuristics for complex multiattribute vehicle routing problems

This paper addresses a multiattribute vehicle routing problem, the rich vehicle routing problem, with time constraints, heterogeneous fleet, multiple depots, multiple routes, and incompatibilities of goods. Four different approaches are presented and applied to 15 real datasets. They are based on two meta-heuristics, ant colony optimization (ACO) and genetic algorithm (GA), that are applied in their standard formulation and combined as hybrid meta-heuristics to solve the problem. As such ACO-GA is a hybrid meta-heuristic using ACO as main approach and GA as local search. GA-ACO is a memetic algorithm using GA as main approach and ACO as local search. The results regarding quality and computation time are compared with two commercial tools currently used to solve the problem. Considering the number of customers served, one of the tools and the ACO-GA approach outperforms the others. Considering the cost, ACO, GA, and GA-ACO provide better results. Regarding computation time, GA and GA-ACO have been found the most competitive among the benchmark.     

Techno-economic and environmental performances of glycerol reforming for hydrogen and power production with low carbon dioxide emissions

This paper is evaluating from the conceptual design, thermal integration, techno-economic and environmental performances points of view the hydrogen and power generation using glycerol (as a biodiesel by-product) reforming processes at industrial scale with and without carbon capture. The evaluated hydrogen plant concepts produced 100,000 Nm³/h hydrogen (equivalent to 300 MW_th) with negligible net power output for export. The power plant concepts generated about 500 MW net power output. Hydrogen and power co-generation was also assessed. The CO₂ capture concepts used alkanolamine-based gas–liquid absorption. The CO₂ capture rate of the carbon capture unit is at least 90%, the carbon capture rate of the overall reforming process being at least 70%. Similar designs without carbon capture have been developed to quantify the energy and cost penalties for carbon capture. The various glycerol reforming cases were modelled and simulated to produce the mass & energy balances for quantification of key plant performance indicators (e.g. fuel consumption, energy efficiency, ancillary energy consumption, specific CO₂ emissions, capital and operational costs, production costs, cash flow analysis etc.). The evaluations show that glycerol reforming is promising concept for high energy efficiency processes with low CO₂ emissions.     

Polydimethylsiloxanes Cross-Linked by 4,4′-(1,3-Phenylenedioxy)-Dianiline within in situ Generated Silica Network

Polydimethylsiloxanes side-functionalized in different degrees with chloromethyl groups were reacted with 4,4′-(1,3-phenylenedioxy)-dianiline when the secondary amino groups formation and cross-linking occur. The reactions were carried out in a silica sol-gel system and thus two networks are simultaneously formed: siloxane-organic network and the silica one. Different techniques were used to characterize the formed systems: FTIR to verify the structure, DMA for analysis of the thermomechanical behavior, SEM and AFM for the evaluation of the morphology and surface topography. The elemental distribution within the samples was determined by EDX. The water vapours sorption capacity was measured in the dynamic regime.     

Assessing gloss under diffuse and specular lighting

The visual sensation of gloss is built on cues deduced from the interaction between light, surfaces sunder evaluation, and surrounding conditions. Gloss is a second-order attribute of the visual appearance, this means that its perception is not directly encoded on biological sensors but constructed from the global scene in the field of view of the observer. It is then a complex quantity to measure. When most studies based on simulated samples stress on the importance of realistic observation conditions, we measure the effect of environment complexity over perception of real samples. We test two different lighting conditions: either diffuse or a combination of diffuse and collimated lighting in order to approach natural complex illumination patterns. Under both lighting conditions, we test two environments: a standard black light booth, designed according to the ASTM D4449, and a realistic office cubicle. Samples consist in a seven-level gloss scale ranging from full matt to high gloss. These are presented to observers through pair comparison protocol, according to a maximum likelihood difference scaling algorithm. Our results confirm that gloss constancy is maintained even if the convergence of illumination varies. We however measure that the constancy is lost for matt samples perception.     

An attempt to identify the presence of polytype stacking faults in hBN powders by means of X-ray diffraction

X-ray diffraction techniques have been used to characterize the three-dimensional order and the crystallite size for 17 hBN powders intended to be used as precursors in the cBN synthesis. Six hBN powders (group A) were obtained by the amidic method (borax + urea) purposely for this research and the remaining 11 hBN powders (group B) were commercial products of recognized companies. Attempts have been made to establish linear correlations between the X-ray revealed parameters of the hBN powders. An explanation sustained on experimental basis is proposed for the different linear correlation between the graphitizing index G.I. and order parameter p₃ in the two groups, that points to the existence of polytype stacking faults in hBN depending on the way of fabrication.     

The influence of silicon substitution on the properties of spherical- and whisker-like biphasic <Emphasis Type="Italic">α</Emphasis>-calcium-phosphate/hydroxyapatite particles

In this work, the influence of the morphology of hydroxyapatite particles on silicon substitution through hydrothermal synthesis performed under the same conditions was investigated. Spherical- and whisker-like hydroxyapatite particles were obtained starting from calcium-nitrate, sodium dihydrogen phosphate, disodium-ethylenediaminetetraacetic acid and urea (used only for the synthesis of whisker-like particles) dissolved in aqueous solutions. Silicon was introduced into the solution using tetraethylorthosilicate. X-ray diffraction, infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy and transmission electron microscopy indicate that silicon doping induce different phase compositions and bioactivity of spherical- and whisker-like hydroxyapatite particles obtained under the same hydrothermal conditions. Silicon-substituted, spherical hydroxyapatites particles showed greater phase transformation to silicon-substituted α- calcium-phosphate compared with whiskers-like hydroxyapatite particles synthesized with the same amount of added silicon. Metabolic activity assay performed with SaOs2 osteosarcoma cells showed better biocompatibility of annealed biphasic spherical-like particles compared with annealed whiskerlike particles while dried spherical-like particles induce high cytotoxicity effect.