Polymer nanoparticles with a sensitive CO2‐responsive hydrophilic/hydrophobic surface

Poly(methyl methacrylate) (PMMA) nanoparticles with a sensitive CO₂‐responsive hydrophilic/hydrophobic surface that confers controlled dispersion and aggregation in water were prepared by emulsion polymerization at 50 °C under CO₂ bubbling using amphiphilic diblock copolymers of 2‐dimethylaminoethyl methacrylate (DMAEMA) and N‐isopropyl acrylamide (NIPAAm) as an emulsifier. The amphiphilicity of the hydrophobic–hydrophilic diblock copolymer at 50 °C was triggered by CO₂ bubbling in water and enabled the copolymer to serve as an emulsifier. The resulting PMMA nanoparticles were spherical, approximately 100 nm in diameter and exhibited sensitive CO₂/N₂‐responsive dispersion/aggregation in water. Using copolymers with a longer PNIPAAm block length as an emulsifier resulted in smaller particles. A higher concentration of copolymer emulsifier led to particles with a stickier surface. Given its simple preparation and reversible CO₂‐triggered amphiphilic behavior, this newly developed block copolymer emulsifier offers a highly efficient route toward the fabrication of sensitive CO₂‐stimuli responsive polymeric nanoparticle dispersions. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 2149–2156     

Semi‐analytical integration of the 8‐node plane element stiffness matrix using symbolic computation

The semi‐analytical integration of an 8‐node plane strain finite element stiffness matrix is presented in this work. The element is assumed to be super‐parametric, having straight sides. Before carrying out the integration, the integral expressions are classified into several groups, thus avoiding duplication of calculations. Symbolic manipulation and integration is used to obtain the basic formulae to evaluate the stiffness matrix. Then, the resulting expressions are postprocessed, optimized, and simplified in order to reduce the computation time. Maple symbolic‐manipulation software was used to generate the closed expressions and to develop the corresponding Fortran code. Comparisons between semi‐analytical integration and numerical integration were made. It was demonstrated that semi‐analytical integration required less CPU time than conventional numerical integration (using Gaussian‐Legendre quadrature) to obtain the stiffness matrix. © 2005 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2006     

Rotation of a Fine Particle with Circularly Polarized Anti-Parallel Collinear Laser Beams

We have succeeded in the operation of rotating a fine particle which was held without mechanical contact by circularly polarized laser beams with opposite propagation directions. A polystyrene latex particle 11.9 μm in diameter deformed in a disk-like shape was dispersed in water, and was trapped using the anti-parallel collinear laser beams which were set up so that they had the circular polarization rotating in the same direction. It was observed that the trapped particle rotated in the same direction as the rotation of the circular polarization of light. Inversion of the rotational direction of the circular polarization of light reversed the direction of the rotation of the particle. Although the rotational speed of a particle varied significantly from particle to particle, it was found to be proportional to the laser beam intensity. A typical value for the rotational speed per beam intensity was 2.1 Hz/W.     

A graph-theoretic approach to modeling metabolic pathways

Summary The metabolic pathways of medazepam, oxazepam, and diazepam were modeled using graph-theoretic transforms which are incorporable into computer-assisted metabolic analysis programs. The information, represented in the form of a graph-theoretic transform kit, which was obtained from these pathways was then used to predict the metabolites of other benzodiazepine compounds. The transform kits gave statistically significant predictions with respect to a statistical method for evaluating the performance of the transform kits.     

代谢综合征的流行病学调查与分析

目的：了解20岁以上成年人代谢综合征的发生率；对比分析其相关的危险因素及保护因素。方法：(1)通过1026名20岁以上成人体检，应用修订的代谢综合征的美国诊断标准，凡具备以下5项标准中3项及3项以上，即①体质指数(BMI)≥24，②甘油三酯ρ(TG)≥150mg／dL，③高密度脂蛋白胆固醇ρ(HDL—C)男＜40mg／dL、ρ(HDL—C)女＜50mg／dL，④空腹血糖ρ(FBC)≥110mg／dL，⑤收缩期血压(SBP)≥130mmHg或舒张期血压(DBP)≥85mmHg或SBP／DBP≥130mmHg／85mmHg(1mmHg＝0．133kPa)，诊断为代谢综合征，共检出136名为病例组。(2)从既往无高血压、糖尿病、冠心病及血脂异常史，且本次筛检未纳入代谢综合征的人群中，抽取与病例组性别、年龄相当的136名进行配对调查分析，计算其相关因素的χ^2值、P值、机会比(OR)值，以及机会比值的95％可信限(OR 95％CI)。结果：(1)从1026名中共检出代谢综合征136名，其发生率为13．26％；(2)调查分析发现摄入过量和长时间处于坐位而又缺乏运动两项可能为代谢综合征的危险因素；而运动可能是代谢综合征的保护因素。结论：(1)本次广东地区部分人群筛查20岁以上成人代谢综合征的发生率为13．26％，虽较美国人为低，但中年组为17．48％，老年组高达29．27％，必须引起重视；(2)坚持终身运动和合理膳食可能是预防代谢综合征的切实可行、经济、有效的措施。     

The role of TLC in the screening of inherited metabolic diseases

Summary Thin-layer chromatography (TLC) is a rapid, reliable and inexpensive screening technique for diagnosis of inherited metabolic diseases (IMD). Our screening program encompasses five main situations where the use of TLC is considered to be vindicated: (i) analysis of amino acids; (ii) screening for sugar defects; (iii) detection of pathological oligosaccharidurias; (iv) screening for organic acid disorders; and (v) detection of abnormalities in tryptophan metabolism. Examples are presented of chromatograms obtained from pathological samples. Presented at the 21^st ISC held in Stuttgart, Germany, 15^th–20^th September, 1996     

Interpretation of the Metabolic Enthalpy Change, ΔHmet,Calculated for Microbial Growth Reactions in Soils

The microcalorimetric method was used to calculate the metabolic enthalpy change per mol of glucose degraded by soil microorganisms, ΔH _met. This parameter has been calculated by microcalorimetry for many organic, inorganic and biochemical reactions, but there is only some information about its quantification for microbial growth reactions in soils. Values of ΔH _met were calculated for different soil samples collected in Galicia (Spain) and Campinas (Săo Paolo, Brazil). Exponential microbial growth was stimulated in all soil samples by the addition of glucose and power-time curves were recorded. Results showed changes in the values of ΔH _met calculated for all the soil samples, suggesting a dependence of this value with the microbial growth rate constant, with the percentage of growth, with the initial number of microorganisms of soil samples, with the quantity of glucose added and with the strain of bacteria growing in soil. The interpretation of variations of ΔH _met provides important qualitative and quantitative information. It reports data that allow to interpret from a qualitative point of view, the increase in biomass as a consequence of the degradation of the organic matter in soil, to understand changes in the percentages of soil organic matter and to know if the microbial population growing in differential soil samples is homogeneous. Therefore, to report that value would be very important in ecological studies, but beforehand, it is necessary to solve some problems that can appear in the experiments done to make the quantification . This revised version was published online in August 2006 with corrections to the Cover Date.     

Biochemical reaction engineering for redox reactions

Redox reactions are still a challenge for biochemical engineers. A personal view for the development of this field is given. Cofactor regeneration was an obstacle for quite some time. The first technical breakthrough was achieved with the system formate/formate dehydrogenase for the regeneration of NADH2. In cases where the same enzyme could be used for chiral reduction as well as for cofactor regeneration, isopropanol as a hydrogen source proved to be beneficial. The coproduct (acetone) can be removed by pervaporation. Whole-cell reductions (often yeast reductions) can also be used. By proper biochemical reaction engineering, it is possible to apply these systems in a continuous way. By cloning a formate dehydrogenase and an oxidoreductase "designer bug" can be obtained where formate is used instead of glucose as the hydrogen source. Complex sequences of redox reactions can be established by pathway engineering with a focus on gene overexpression or with a focus on establishing non-natural pathways. The success of pathway engineering can be controlled by measuring cytosolic metabolite concentrations. The optimal exploitation of such systems calls for the integrated cooperation of classical and molecular biochemical engineering.     

Earthshaker: A mobile rescue robot for emergencies and disasters through teleoperation and autonomous navigation

To deal with emergencies and disasters without rescue workers being exposed to dangerous environments, this paper presents a mobile rescue robot, Earthshaker. As a combination of a tracked chassis and a six-degree-of-freedom robotic arm, as well as miscellaneous sensors and controllers, Earthshaker is capable of traversing diverse terrains and fulfilling dexterous manipulation. Specifically, Earthshaker has a unique swing arm—dozer blade structure that can help clear up cumbersome obstacles and stabilize the robot on stairs, a multimodal teleoperation system that can adapt to different transmission conditions, a depth camera-aided robotic arm and gripper that can realize semiautonomous manipulation and a LiDAR aided base that can achieve autonomous navigation in unknown areas. It was these special systems that supported Earthshaker to win the first Advanced Technology & Engineering Challenge (A-TEC) championships, standing out of 40 robots from the world and showing the efficacy of system integration and the advanced control philosophy behind it.