Molecular Epidemiology of Enteroaggregative Escherichia coli (EAEC) Isolates of Hospitalized Children from Bolivia Reveal High Heterogeneity and Multidrug-Resistance

Enteroaggregative Escherichia coli (EAEC) is an emerging pathogen frequently associated with acute diarrhea in children and travelers to endemic regions. EAEC was found the most prevalent bacterial diarrheal pathogen from hospitalized Bolivian children less than five years of age with acute diarrhea from 2007 to 2010. Here, we further characterized the epidemiology of EAEC infection, virulence genes, and antimicrobial susceptibility of EAEC isolated from 414 diarrheal and 74 non-diarrheal cases. EAEC isolates were collected and subjected to a PCR-based virulence gene screening of seven virulence genes and a phenotypic resistance test to nine different antimicrobials. Our results showed that atypical EAEC (a-EAEC, AggR-negative) was significantly associated with diarrhea (OR, 1.62, 95% CI, 1.25 to 2.09, p < 0.001) in contrast to typical EAEC (t-EAEC, AggR-positive). EAEC infection was most prevalent among children between 7–12 months of age. The number of cases exhibited a biannual cycle with a major peak during the transition from warm to cold (April–June). Both typical and a-EAEC infections were graded as equally severe; however, t-EAEC harbored more virulence genes. aap, irp2 and pic were the most prevalent genes. Surprisingly, we detected 60% and 52.6% of multidrug resistance (MDR) EAEC among diarrheal and non-diarrheal cases. Resistance to ampicillin, sulfonamides, and tetracyclines was most common, being the corresponding antibiotics, the ones that are frequently used in Bolivia. Our work is the first study that provides comprehensive information on the high heterogenicity of virulence genes in t-EAEC and a- EAEC and the large prevalence of MDR EAEC in Bolivia.     

Adaptive actuator failure compensation for cooperative robotic manipulators with parameter uncertainties

This article develops a new framework of adaptive actuator failure compensation control for cooperative manipulator systems with parameter uncertainties in addition to actuator failures, and designs and analyzes effective actuator failure compensation schemes for such robotic systems. The new adaptive control design uses an integration of multiple individual failure compensators and direct adaptation to handle various types of uncertainties in such robotic systems. The design can also be used for concurrent actuator failure cases, to expand the capability of adaptive actuator failure compensation. With a complete proof and performance analysis, it is shown that the proposed control scheme guarantees the desired closed-loop stability and asymptotic output tracking, despite actuator failures whose patterns, time instants and values are all unknown. Simulation results of a benchmark cooperative manipulator system are presented to verify the desired control performance of the system with both typical constant and square-wave actuator failure signals.     

Production of angiotensin-converting enzyme inhibitory peptides in Iranian ultrafiltered white cheese prepared with Lactobacillus brevis KX572382

In this study, ultrafiltered (UF) Iranian white cheese made with adjunct cultures including six Lactobacillus isolates (Lactobacillus brevis, L. casei and L. plantarum) from traditional Iranian Motal cheese. The peptide extract (<5 kDa) of cheese samples were assessed for angiotensin-converting enzyme (ACE)-inhibitory activity during ripening (5 °C). Among the strains used, L. brevis KX572382 (M8) was selected because of the greater increase in (ACE)-inhibitory activity in the cheese (P < 0.05). The highest activity of M8 extract was observed on the 28th (71.72%) day of ripening (P < 0.05). Proteolytic activity assessment and RP-HPLC peptide profile of M8 water-soluble extracts (WSEs) indicated the effect of M8 on further protein degradation due to secondary proteolysis. A total of 7 different peptide sequences, previously known in the literature for their ACE-inhibitory activity, were tentatively identified by LC/ESI-MS in 28-day M8 peptide extract. Although the effect of M8 on pH and the proteolysis development in cheese was significant, no adverse effect was observed on the sensory properties. In conclusion, M8 strain can enhance the functional properties of Iranian UF white cheese.     

油莎豆白酒发酵工艺优化及其品质指标检测

以油莎豆饼和高粱为原料，分别采用固态和液态发酵工艺酿造油莎豆白酒，对油莎豆白酒的发酵工艺进行选择。在此基础上，采用单因素试验及正交试验探究发酵温度、糖化酶添加量以及活性干酵母添加量对油莎豆白酒发酵及理化指标的影响，从而确定油莎豆白酒的最佳固态发酵工艺条件，并对油莎豆白酒发酵过程中酒醅的发酵指标进行实时监测。结果表明，油莎豆白酒的最佳发酵工艺为固态发酵，最佳发酵工艺条件为发酵温度23 ℃，糖化酶添加量190 U/g、活性干酵母添加量0.5‰。在此优化条件下，油莎豆白酒的酒精度为9.2%vol，总酯含量为2.96 g/L，总酸含量为1.45 g/L，乙酸乙酯含量为2.42 g/L，出酒率达到41%。油莎豆白酒发酵过程中，酒精含量逐渐升高，最后趋于平缓，发酵结束后，酒精度达9.2%vol；发酵温度先上升后下降，第6天时酒醅温度达到峰值（27.9 ℃）；剩余淀粉含量逐渐下降，发酵结束后，淀粉消耗12.21%。     

Effect of co-fermentation and sequential fermentation of Candida versatilis and Lactococcus lactis subsp. cremoris on unsalted pork hydrolysates components

In this study, the effect of co-fermentation and sequential fermentation with a typical halophilic soy sauce yeast Candida versatilis and a non-halophilic dairy bacterium Lactococcus lactis subsp. cremoris in pork hydrolysates was explored for the first time with regard to their viability, physicochemical changes and volatile compound production. It was observed that the growth of C. versatilis was suppressed (only 0.6 - 1.5 log CFU mL⁻¹ increase), whilst L. lactis subsp. cremoris was stimulated (total cell counts exceeded 9.0 log CFU mL⁻¹) in mixed-cultures relative to the respective monocultures. There were no significant differences between co-inoculation and sequential inoculation regarding glucose consumption, organic acid production and free amino acids utilisation. Some distinct volatile compounds such as methionol, 6-methyl-5-hepten-2-one and gamma-nonalactone were found in both co-inoculated and sequentially inoculated samples, with slightly different concentrations. These results suggest that the mixed-inoculation of C. versatilis and L. lactis have a positive impact on the volatile compounds formation in pork hydrolysates.     

Coherent control of symmetric and asymmetric diffraction grating via relative phase

ABSTRACT

We present a theoretical model to realize the symmetric and asymmetric diffraction grating in a four-level atomic medium. The proposed atomic medium follows a double lambda configuration where four fields interact with it. We get control over symmetric and asymmetric behavior of the diffraction grating by manipulating the relative phase of the fields. Interestingly, the symmetric and asymmetric diffraction grating become prominent when the vortex beam is used instead of the plane wave. Enhanced first, second, and third-order diffraction gratings are achieved via the vortex beam. Further, we find control over asymmetric diffraction gratings by the relative phase of the fields. Coherent control of asymmetric diffraction grating in negative and positive diffracted angles is also achieved via the relative phase.     

“电力系统分析”课程可持续发展的建设与实践

本文探索了新工科背景下“电力系统分析”课程建设情况,摸索工程教育的新理念,以学生发展为中心,尝试翻转课堂的互动式教学模式,实现了创新人才的培养目标。编著《电力系统分析》教材,实现了内容的继承和创新、重要知识点的交叉和融合。建设数字仿真及物理模拟实验室,解决高校人才培养与社会需求脱节的问题。以“注重学习过程,加强平时考核,淡化期末考试”的方式进行综合考评,提高了教学效果与教学质量。经过几年的教学探索与实践,证明了本课程建设效果良好。     

The management of the project-based organization: A personal reflection

In this paper I make a personal reflection on my research and writings in the field of Project Management over the past 30 years. My research has primarily been about the management of the project-based organization. Within that I have researched governance, organizational behaviour, contingency, marketing, success and shareholder value.     

Size and morphology-controlled synthesis of mesoporous hydroxyapatite nanocrystals by microwave-assisted hydrothermal method

We report the rapid microwave-assisted hydrothermal synthesis of mesoporous hydroxyapatite (HAp) nanocrystals with controlled size, morphology, and surface area using various organic modifiers as regulators. The products were analyzed for their crystalline nature, phase purity, morphology, particle size and pore size distribution. Results indicated that ascorbic acid, cetyltrimethyl ammonium bromide (CTAB) and polyvinylpyrrolidone (PVP) play an important role to obtain needle like, rod like and fiber like mesoporous HAp nanocrystals with different specific surface area by controlling growth habit of HAp along c-axis. In addition, the prepared samples were B-type carbonated HAp similar to bone minerals. Therefore, the present approach can be a promising way to obtain precursor for making tissue engineering scaffolds, drug/protein delivery carriers and bone fillers with tunable characteristics.     

钻削GH4169高温合金薄壁件钻削力仿真研究

GH4169高温合金的薄壁钻孔与厚壁钻孔相比有特殊性,运用ABAQUS软件进行钻削GH4169高温合金薄壁件的仿真,研究钻削加工过程中钻削参数和工件厚度对钻削力的影响规律及变化特征,分析应力的分布规律。结果表明:钻削初期,横刃的挤压和主切削刃切削长度的增加使钻削力和扭矩增大;稳定钻削阶段,横刃切出后,主切削刃切削长度不变切削直径增加,钻削力和扭矩稳定增加;钻削后期,副切削刃参与切削,主切削刃切削长度减小,轴向钻削力和扭矩减小,但副刃与孔壁的挤压摩擦,曲线波动较大;钻削速度、进给量及工件厚度的增加都会导致轴向钻削力和扭矩的增加;钻削时的最大应力分布在横刃和主切削刃与工件的接触部位。