Current Issue : April - June Volume : 2018 Issue Number : 2 Articles : 5 Articles
Quantum confinement of semiconductor nanoparticles is a potential feature which can be interesting for photocatalysis,\nand cadmium selenide is one simple type of quantum dot to use in the following photocatalytic degradation of organic dyes.\nCdSe nanoparticles capped with polyvinylpyrrolidone (PVP) in various concentration ratios were synthesized by the chemical\nreduction method and characterized. The transmission electron microscopy (TEM) analysis of the samples showed that 50%\nPVP-capped CdSe nanoparticles were uniformly distributed in size with an average of 2.7nm and shape which was spherical-like.\nThe photocatalytic degradation of methyl blue (MB) in water showed efficiencies of 31% and 48% when using uncapped and 50%\nPVP-capped CdSe nanoparticles as photocatalysts, respectively. The efficiency of PVP-capped CdSe nanoparticles indicated that\na complete green process can be utilized for photocatalytic treatment of water and waste water....
A highly efficient soil-burrowing dung beetle possesses an intricate outer contour curve on its foreleg end-tooth. This study\nwas carried out based on evidence that this special outer contour curve has the potential of reducing soil penetration\nresistance and could enhance soil-burrowing efficiency. A toothed wheel is a typical agricultural implement for soil\nimprinting, to increase its working efficiency; the approach of the bionic geometrical structure was utilized to optimize the\ninnovative shape of imprinting toothed wheel. Characteristics in the dung beetle�s foreleg end-tooth were extracted and\nstudied by the edge detection technique. Then, this special outer contour curve was modeled by a nine-order polynomial\nfunction and used for the innovative design of imprinting the tooth�s cutting edge. Both the conventional and bionic teeth\nwere manufactured, and traction tests in a soil bin were conducted. Taking required draft force and volume of imprinted\nmicrobasin as the evaluating indexes, operating efficiency and quality of different toothed wheels were compared and\ninvestigated. Results indicate that compared with the conventional toothed wheel, a bionic toothed wheel possesses a better\nforward resistance reduction property against soil and, meanwhile, can enhance the quality of soil imprinting by increasing\nthe volume of the created micro-basin....
In this study, we identified a low-dimensional representation of control mechanisms in throwing motions from a variety of subjects\nand target distances. The control representation was identified at the kinematic level in task and joint spaces, respectively, and at the\nmuscle activation level using the theory of muscle synergies. Representative features of throwing motions in all of these spaces were\nchosen to be investigated. Features were extracted using factorization and clustering techniques from the muscle data of\nunexperienced subjects (with different morphologies and physical conditions) during a series of throwing tasks. Two synergy\nextraction methods were tested to assess their consistency. For the task features, the degrees of freedom (DoF), and the muscles\nunder study, the results can be summarized as (1) a control representation across subjects consisting of only two synergies at the\nactivation level and of representative features in the task and joint spaces, (2) a reduction of control redundancy (since the\nnumber of synergies are less than the number of actions to be controlled), (3) links between the synergies triggering intensity\nand the throwing distance, and finally (4) consistency of the extraction methods. Such results are useful to better represent\nmechanisms hidden behind such dynamical motions and could offer a promising control representation for synthesizing\nmotions with muscle-driven characters....
A series of cobalt (Co) and its oxides based nanoparticles were synthesized by using hyperbranched polyester polyol Boltorn\nH20 as a platform and sodium borohydride as a reducing agent. UV, FT-IR, XRD, NTA, and TEM methods were employed to\nobtain physicochemical characteristics of the products. The average diameter of Co nanoparticles was approximately 8.2 �± 3.4 nm.\nTheir magnetic properties, including hysteresis loop, field-cooled, and zero field-cooled curves were investigated.The nanoparticles\nexhibit superparamagnetism at room temperature, accompanied by magnetic hysteresis below the blocking temperature....
In the complex tumor microenvironment, chemical and mechanical signals from tumor cells, stromal cells, and the surrounding\nextracellular matrix influence all aspects of disease progression and response to treatment. Modeling the physical properties of the\ntumor microenvironment has been a significant effort in the biomaterials field. One challenge has been the difficulty in altering the\nmechanical properties of the extracellular matrix without simultaneously impacting other factors that influence cell behavior. The\ndevelopment of novel materials based on nanotechnology has enabled recent innovations in tumor cell culture models. Here, we\nreview the various approaches by which the tumor cell microenvironment has been engineered using natural and synthetic gels.\nWe describe new studies that rely on the unique temporal and spatial control afforded by nanomaterials to produce culture\nplatforms that mimic dynamic changes in tumor matrix mechanics. In addition, we look at the frontier of nanomaterial-hydrogel\ncomposites to review new approaches for perturbation of mechanochemical control in the tumor micro environment....
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