Structural features of the polysaccharide gum from Acacia glomerosa

Acacia glomerosa, Benth. (Vulgares Series) exudates a clear gum which produces gels easily. The physico-chemical data and sugar composition are very close to gum arabic from Acacia senegal, except that A. glomerosa gum contains a high nitrogen content. A series of degraded products was prepared by acid hydrolysis and Smith-degradation. The characterization of the degraded products by partial hydrolysis, sugar composition and by the application of uni- and bidimensional spectroscopy led to know interesting structural features of the polysaccharide isolated from A. glomerosa gum. This polysaccharide, as that from A. senegal gum, consists of 1,3-β- -galactopyranosyl backbone. There are side-chains of 1,3-β- -galactopyranosyl oligosaccharides attached to position six of the galactan main chain. Arabinose (furanosyl and pyranosyl) residues may be up to four units long because it was necessary to prepare four polysaccharides to remove them from the gum structure. Uronic acid residues were difficult to remove as has been observed in other Acacia gums.     

Telerehabilitation using a virtual environment improves upper extremity function in patients with stroke.

In this paper, we describe our experience in designing a virtual environment-based (VE) telerehabilitation system, and the results of a clinical study of the first 11 subjects with stroke to use the system. Our telerehabilitation system allows a therapist to conduct interactive VE treatment sessions remotely with a patient who is located at home. The system, software architecture, and development experience are described. Results of the clinical study on subjects with stroke showed significant improvements in upper extremity function following 30 1-h VE treatment sessions as measured by three standard clinical tests: Fugl-Meyer test of motor recovery (FM) (p < 0.0001), Wolf motor test (WMT) (p = 0.0097, and shoulder strength (ShS) (p = 0.0027). Grip strength (GS) showed a trend toward improvement (p = 0.025). These changes were maintained, for the most part, at four-months follow-up (FM +7.6, WMT -18.4 s, ShS, +169%, GS, +53%).     

Dynamic Reaction Cell-ICP-MS as a Powerful Tool for Quality Control of a Se-Enriched Dietary Supplement

The aim of this work was to evaluate different approaches employing a reaction cell to circumvent spectral interferences over ⁸⁰Se⁺ to increase the sensitivity in the determination of Se by inductively coupled plasma mass spectrometry (ICP-MS). Different gases (NH₃, CH₄, and O₂) were employed, and the operating conditions were optimized by a central composite design, evaluating the effect of the reaction gas flow rate and the rejection parameter q (Rpq) on the limit of detection (LOD) of the method. All reaction gases studied reduced the interference by ⁴⁰Ar₂ ⁺ over ⁸⁰Se⁺, reducing the LOD when compared to the LOD obtained with ICP-MS operating in the standard mode (LOD = 0.2 μg kg^?1). A better LOD (0.01 μg kg^?1) was obtained with CH₄, while 0.1 μg kg^?1 was the LOD with NH₃. The use of O₂ as a reaction gas enabled the determination of Se at m/z 96 (⁸⁰Se¹⁶O⁺) with adequate analytical performance (LOD = 0.03 μg kg^?1). The accuracy of the method was evaluated by analyzing the certified reference material (CRM) Selm-1, and the results obtained ranged from 99 to 104% of the certified value. In addition, Se dietary supplements of four different brands and commercial yeast were analyzed, and the major sources of uncertainty were studied. The dietary supplements followed the criteria adopted by Brazilian legislation, although the uncertainty study highlighted the great variation in the Se content of each brand. Clearly, the manufacturing process of dietary supplements needs more rigorous quality control, considering that this product can affect the health of consumers.     

曼哈顿世界环境下消失点非线性优化估计算法

目的 符合曼哈顿假设的结构化场景简称曼哈顿世界,具有丰富的场景结构特征。消失点作为直线的潜在观测,是一种全局信息,可以显式地体现载体坐标系与世界坐标系之间的姿态关系。为更加准确地估计消失点,本文针对单目图像,同时考虑实时性和准确性,提出了具有更高精度的基于非线性优化的消失点估计算法。方法 分析目前性能最优的基于随机采样一致性（random sample consistency,RANSAC）的消失点估计方法,通过对直线单参数化、利用正交性约束生成候选假设以及RANSAC过程的重点分析与改进,更加快速准确地得到消失点估计,为后续优化提供初值。利用直线分类时计算的误差度量构建最小二乘优化模型,采用非线性优化方法迭代求解,并采用鲁棒核函数保证迭代的精确性和结果的最优性。结果 通过仿真实验和基于公共数据集的实验对本文提出算法与目前性能最优算法进行比较。仿真实验中,相比于RCM（R3_CM1）及RCMI（R3_CM1_Iter）,本文算法结果在轴角形式下的角度偏差减小了24.6%;有先验信息约束时,角度偏差降低一个数量级,仅为0.06°,精度大幅提高。在YUD（York urban city databbase）数据集中,本文算法相较于RCM和RCMI,角度偏差分别减小了27.2%和23.8%,并且80%的消失点估计结果角度偏差小于1.5°,性能明显提升且更具稳定性。此外,本文算法在仿真实验对每一图像帧的平均优化耗时为0.008 s,可保证整体的实时性。结论 本文提出的消失点估计算法,对基于RANSAC的方法进行了改进,在不影响实时性的基础上,估计结果更加准确、鲁棒,并且更具稳定性。     

Deasphalting process using supercritical water

The authors aimed to study the deasphalting process on laboratory scale through the design and development of a supercritical extraction experimental unit. The experimental unity used in tests is composed by a pump, an extractor with useful volume of 3 L and one separator vessel. Extractions in supercritical condition were carried out using petroleum residue (vacuum residuum) as feedstock and water as solvent. Temperature and pressure were manipulated to maintain the solvent in the required conditions, thus facilitating the extraction process and avoiding sharp changes in the system. In both phases, the products in the deasphalted oil stream present adequate characteristics for the production of lubricant oils and those in the asphalt residue stream present an elevated concentration of asphalt molecules.     

The “Panopticon” of search engines: the response of the European data protection framework

Nowadays, Internet users are depending on various search engines in order to be able to find requested information on the Web. Although most users feel that they are and remain anonymous when they place their search queries, reality proves otherwise. The increasing importance of search engines for the location of the desired information on the Internet usually leads to considerable inroads into the privacy of users. A heated debate is currently ongoing at European level regarding the question if search engine providers that are established outside the European Union are covered by the European data protection framework and the obligations it imposes on entities that process personal data. The scope of this paper is to examine the applicability of the European data protection legislation to non-EU-based search engine providers and to study the main privacy issues with regard to search engines, such as the character of search logs, their anonymisation and their retention period. Ixquick, a privacy-friendly meta-search engine, will be presented as an alternative to privacy intrusive existing practices of search engines.     

Reverse osmosis technology for water treatment: State of the art review

This paper presents a review of recent advances in reverse osmosis technology as related to the major issues of concern in this rapidly growing desalination method. These issues include membrane fouling studies and control techniques, membrane characterization methods as well as applications to different water types and constituents present in the feed water. A summary of the major advances in RO performance and mechanism modeling is also presented and available transport models are introduced. Moreover, the two important issues of RO brine discharge and energy costs and recovery methods are discussed. Finally, future research trends and needs relevant to RO are highlighted.     

Sugarcane cell wall structure and lignin distribution investigated by confocal and electron microscopy

Lignocellulosic plant cell wall is considered a potential source for second generation biofuels. The plant cell wall is a highly complex structure mainly composed of cellulose, hemicelluloses, and lignin that form a network of crosslinked fibers. The structural organization of the sugarcane cell wall has not been previously analyzed in detail, and this analysis is a prerequisite for further studies on the recalcitrance and deconstruction of its biomass. In this work, cellulose and lignin localization were investigated by confocal laser scanning microscopy. In addition, the internode sugarcane cell wall structural organization was analyzed by electron microscopy. Internode stem anatomy showed a typical monocot structure consisting of epidermis, hypoderm, and vascular bundles scattered throughout ground parenchyma tissue and surrounded by sclerenchyma fibers. Confocal images of safranin labeled sugarcane showed that lignin distribution was predominant in the vessel elements, cell wall corners (CC), and middle lamella (ML), while cellulose‐rich cell walls were randomly distributed in the ML and organized in the other cell wall layers. KMnO₄ cytochemistry revealed that lignin was predominantly distributed in secondary cell walls, ML and CC. Cell wall sublayers (S1, S2, and S3) were identified and measured by transmission electron microscopy. Our results provide insights that may help further understanding of sugarcane cell wall organization, which is crucial for the research and technology of plant‐based biofuel production. Microsc. Res. Tech. 76:829–834, 2013. © 2013 Wiley Periodicals, Inc.     

17β-Estradiol Increases Liver and Serum Docosahexaenoic Acid in Mice Fed Varying Levels of α-Linolenic Acid

Docosahexaenoic acid (DHA) is considered to be important for cardiac and brain function, and 17β-estradiol (E2) appears to increase the conversion of α-linolenic acid (ALA) into DHA. However, the effect of varying ALA intake on the positive effect of E2 on DHA synthesis is not known. Therefore, the objective of this study was to investigate the effects of E2 supplementation on tissue and serum fatty acids in mice fed a low-ALA corn oil-based diet (CO, providing 0.6 % fatty acids as ALA) or a high ALA flaxseed meal-based diet (FS, providing 11.2 % ALA). Ovariectomized mice were implanted with a slow-release E2 pellet at 3 weeks of age and half the mice had the pellet removed at 7 weeks of age. Mice were then randomized onto either the CO or FS diet. After 4 weeks, the DHA concentration was measured in serum, liver and brain. A significant main effect of E2 was found for liver and serum DHA, corresponding to 25 and 15 % higher DHA in livers of CO and FS rats, respectively, and 19 and 13 % in serum of CO and FS rats, respectively, compared to unsupplemented mice. There was no effect of E2 on brain DHA. E2 results in higher DHA in serum and liver, at both levels of dietary ALA investigated presently, suggesting that higher ALA intake may result in higher DHA in individuals with higher E2 status.     

Simulating the effect of aerobic biodegradation on soil vapor intrusion into buildings: influence of degradation rate, source concentration, and depth

Steady-state vapor intrusion scenarios involving aerobically biodegradable chemicals are studied using a three-dimensional multicomponent numerical model. In these scenarios, sources of aerobically biodegradable chemical vapors are placed at depths of 1-14 m beneath a 10 m x 10 m basement or slab-on-grade construction building, and the simultaneous transport and reaction of hydrocarbon and oxygen vapors are simulated. The results are presented as Johnson and Ettinger attenuation factors alpha (predicted indoor air hydrocarbon concentration/source vapor concentration), and normalized contour plots of hydrocarbon and oxygen concentrations. In addition to varying the vapor source depth, the effects of source concentration (2-200 mg chemical/L vapor) and oxygen-limited first-order reaction rates (0.018-1.8 h(-1)) are studied. Hydrocarbon inputs were specific to benzene, although the relevant properties are similar to those for a range of hydrocarbons of interest. Overall, the results suggest that aerobic biodegradation could play a significant role in reducing vapor intrusion into buildings (decreased alpha-values) relative to the no-biodegradation case, with the significance of aerobic biodegradation increasing with increasing vapor source depth, decreasing vapor source concentration, and increasing first-order biodegradation rate. In contrast to the no-biodegradation case, differences in foundation construction can be significant in some settings. The significance of aerobic biodegradation is directly related to the extent to which oxygen is capable of migrating beneath the foundation. For example, in the case of a basement scenario with a 200 mg/L vapor source located at 3 m bgs, oxygen is consumed before it can migrate beneath the foundation, so the attenuation factors for simulations with and without aerobic biodegradation are similar for all first-order rates studied. For the case of a 2 mg/L vapor source located at 8 m bgs, the oxygen is widely distributed beneath the foundation, and the attenuation factor for the biodegradation case ranges from about 3 to 18 orders-of-magnitude less than that for the no-biodegradation case.