A review of different pinch techniques

Individuals often pinch with preferred pinch techniques based on their experience and familiarity. However, researchers believe that pinch force exertions are not comparable across different pinch techniques. Hence, it is possible to pinch objects with incompatible pinch techniques during manual handling. This increases risks of developing musculoskeletal disorders. The preceding problem substantiates the need for a comprehensive understanding of definitions, categorisations and capacities of different pinch techniques. Nevertheless, the knowledge on pinch techniques appears to be highly dispersed and not compiled to a level systematic enough for further research. Thus, this review aims to develop a consolidated theoretical groundwork on pinch techniques. It presents an anthology of terminologies, previous findings and concepts underpinning different pinch techniques. While much research is still required, it is believed that an improved understanding on pinch techniques is now within sight, due to, in part, a structured review of their definitions, classifications and capacities.     

Asymmetric Catalysis in Confined Space Provided by l-Proline Functionalized Mesoporous Silica with Plugs in the Pore

Mesoporous silica having l-proline functionality and plugged pore structure was synthesized by direct microwave synthesis under acidic condition using Pluronic P123 as template and sodium metasilicate nonahydrate as silica source. The direct synthesis resulted in the prismatic or disk types with short channels and plugs in the pore structure. Due to the presence of plugs, dual mesoporosities with 7 and 3 nm pore diameter were generated leading to an existence of cavitation. Tri-functionality of this materials i.e. chiral organofunctional group, plugs, and short channel, would be useful for the asymmetric diethyl malonate addition reaction and asymmetric epoxidation reaction of α,β-unsaturated aldehydes. We proved that the formation of plugs in the mesoporous silica governs the formation of dual mesoporosities providing an enhancement of enantiomeric excess in the asymmetric catalysis. This finding might open an important application of the amino-acid organo multifunctionalized mesoporous silica for asymmetric reactions.     

Signal amelioration of electrophoretically deposited whole-cell biosensors using external electric fields

This paper presents an integrated whole-cell biochip system where functioning cells are deposited on the solid micro-machined surfaces while specially designed indium tin oxide electrodes that can be used to apply controllable electric fields during various stages; for example during cell deposition. The electrodes can be used also for sensing currents associated with the sensing mechanisms of electrochemical whole-cell biosensors. In this work a new approach integrating live bacterial cells on a biochip using electrophoretic deposition is presented. The biomaterial deposition technique was characterized under various driving potentials and chamber configurations. An analytical model of the electrophoretic deposition kinetics was developed and presented here. The deposited biomass included genetically engineered bacterial cells that may respond to toxic material exposure by expressing proteins that react with specific analytes generating electrochemically active byproducts. In this study the effect of external electric fields on the whole-cell biochips has been successfully developed and tested. The research hypothesis was that by applying electric fields on bacterial whole-cells, their permeability to the penetration of external analytes can be increased. This effect was tested and the results are shown here. The effect of prolonged and short external electric fields on the bioelectrochemical signal generated by sessile bacterial whole-cells in response to the presence of toxins was studied. It was demonstrated that relatively short 10 ms external DC electric pulse improves the performance of bacterial biosensors by 15% relative to un-biased biosensors. The application of prolonged 1 h external alternating electric fields deteriorated the whole-cell performance in the presence of toxins. In this paper we present the electrode apparatus and methods, as well as the characterization results, e.g. signal vs. time and induction factor, of such chips and discussing the highlight and problems of this new concept.     

Enhanced removal of humic acid from water by micelle-montmorillonite composites: Comparison to granulated activated carbon

Removal of humic acid (HA) from water by octadecyltrimethyl-ammonium (ODTMA) micelle–montmorillonite (MMT) composites and by granulated activated carbon (GAC) was studied in dispersion and by filtration. FTIR measurements emphasized that the ODTMA micelle–clay-mineral composite differs from the ODTMA monomer-clay-mineral one. HA adsorption by GAC in dispersion was moderately reduced from 100% initially to 75% with an increase in HA concentrations. In contrast, the fractions adsorbed by the composite increased monotonically with HA concentrations from very low adsorption up to 80%. This effect was explained by the presence of a small concentration of ODTMA monomers in dispersion, which adsorbed on the negatively charged HA and partially neutralized it, or caused charge reversal, which in turn inhibited HA adsorption by the positively charged composite. This effect was verified by mobility measurements and was found to be more pronounced at low HA concentrations. This trend of increase in HA removal with an increase in HA concentration (3 and 10 ppm) was also observed in filtration (50% and 85% removal, respectively), when employing columns of the composite mixed with sand (to improve flow). Throughout the experiment the removal of high HA concentration (10 ppm) by the composite filter remained ~ 80% whereas, the removal by the GAC filter decreased from an initial 80% removal to a complete recovery of the HA (no removal) after the passage of 20 L (200 pore volumes). Upon applying sand of higher quality in the columns the removal of low HA concentrations was nearly complete by the composite column while the GAC only slightly contributed to its removal (for a passage of 100 L (1000 pore volumes)).     

M-learning in review： Technology, standard and evaluation

Nowadays E-learning as a form of learning depending on networks and computer devices has been expanding by leaps and bounds. As a special kind of E-learning, M-learning （mobile learning） aims at the use of mobile devices anywhere at anytime by anybody. In this paper, the technologies to develop a M-learning system are deeply analyzed according to the layer model at first. Then, from the view of application, the standardization in M-learning is researched in order to accelerate the development and popularization of M-learning. Finally, quality estimation of M-learning system is discussed from the view of QoE （quality of experiences）. The experience form end-user is the sole effective norm to judge the result of M-learning technology. It is no doubt that technologies, standardization and evaluation will play very important parts in the course of M-leaming development.     

On Error Bounds of Finite Difference Approximations to Partial Differential Equations—Temporal Behavior and Rate of Convergence

This paper considers a family of spatially semi-discrete approximations, including boundary treatments, to hyperbolic and parabolic equations. We derive the dependence of the error-bounds on time as well as on mesh size.     

Intralaminar Damage Model for Laminates Subjected to Membrane and Flexural Deformations

Prediction of transverse damage initiation and evolution for not necessarily symmetric laminates under membrane and/or bending loads is the subject of this work. The laminate stiffness reduction is computed via crack opening displacement (COD) methods and the generalization to multiple cracking laminas is made via continuum damage mechanics (CDM) concepts. Using available COD solutions combined with homogenization techniques leads to an analytical constitutive model capable of predicting the initiation and evolution of crack density versus applied strain, as well as laminate modulus degradation, not only for symmetric laminates subjected to membrane deformation but also for general laminates subjected to flexural deformations as well. To adjust the model parameters, experimental data is required in the form of crack density, or modulus reduction, versus strain for two laminates of the same material system. Then, the model is capable of predicting crack density and modulus degradation for other laminate stacking sequences. The model takes into account crack closure, which is important under flexure, as well as the case of the center lamina straddling the neutral axis. The effect of thermal stresses is incorporated in the formulation.     

动态连续电解还原制备四价铀的研究

研究了ＵＯ２（ＮＯ３）２－ＨＮＯ３－Ｎ３Ｈ５ＮＯ３－Ｈ２Ｏ体系中，用三级串联电解槽动态连续电解还原制备四价铀的方法，在确定的工艺条件下，当进料液Ｕ（ＶＩ）浓度为１８０ｇ／Ｌ，硝酸浓度为３．１４ｍｏｌ／Ｌ，肼浓度为０．２１０ｍｏｌ／Ｌ，加料速度为２００ｍＬ／ｈ时，可连续制备得到了四价铀浓度大于１５０ｇ／Ｌ的产品溶液。