Antibacterial and in vivo reactivity of bioactive glass and poly(vinyl alcohol) composites prepared by melting and sol-gel techniques

Bioactive glass particle is used in the repair of bone defects. This material undergoes a series of surface in vivo reactions, which leads to osteointegration. We evaluated the effect of the bioactive glass synthesis, sol-gel (BG(S)) versus melting (BG(M)), associated with polyvinyl-alcohol (PVA) on in vivo bioactivity with biochemical parameters, liver-kidney histological structure and antibacterial in vitro activity. These composites were testified in many bacteria and implanted in ovariectomized rat. The serum and organs (liver and kidney) of all groups, control and treated rats, were collected to investigate the side effects of our composites, BG(S)-PVA and BG(M)-PVA, in comparison with control and ovariectomized rats. Also, the implants, before and after implantation, were prepared for analysis using physicochemical techniques such as Fourier transform infrared spectroscopy and X-ray diffraction. Our results have shown the stability of natremia, kaliemia, calcemia and phosphoremia. The histological structures of liver and kidney in implanted rats are intact compared to control and ovariectomized rats. BG(S)-PVA is characterized by a higher antibacterial effect on negative and positive gram bacteria than BG(M)-PVA. The physicochemical results have confirmed a progressive degradation of BG(S)-PVA and BG(M)-PVA, while replacing the implant by an apatite layer. But this bioactivity of BG(S)-PVA is faster than BG(M)-PVA. We can therefore confirm, on the one hand, the biocompatibility of our two implants and, on the other hand, the beneficial effect of sol-gel synthesis technique versus melting, both on the antibacterial effect and on the rapid formation of layer hydroxyapatite, and consequently on osteogenesis.     

Maximum finger force prediction using a planar simulation of the middle finger

Maximum isometric finger-grip forces were predicted using a biomechanical model for plane motion of the middle finger. In the course of this study, mathematical representations of tendon displacement, the moment arm of tendon at the finger joints and muscle force-length relationship were investigated. The information gathered was applied to the model to estimate the maximum grip force of the middle finger gripping cylinders of different sizes. Muscle force per unit physiological cross-section area of 30 N/cm2 resulted in good agreement with measured force. However, for finger postures having an acute proximal interphalangeal joint angle, the estimated force was greater than that measured. Various joint angles were applied to the model to simulate the wrist and finger postures not limited to the cylinder grip. In general the finger force was greatest with the wrist in its extended position and at acute flexion of the proximal interphalangeal joint. The maximum finger force occurred at reduced metacarpophalangeal joint angles as the wrist joint changed from an extended position to a flexed one. It is also postulated that muscle force-length relationship is an important factor in muscle force predictions. The data obtained by this research are useful for the design of handles and the current model is applicable to the analysis of hand postures for workers using hand tools.     

System‐Level Performance of Limited Feedback Schemes for Massive MIMO

To implement high‐order multiuser multiple input and multiple output (MU‐MIMO) for massive MIMO systems, there must be a feedback scheme that can warrant its performance with a limited signaling overhead. The interference‐to‐noise ratio can be a basis for a novel form of Codebook (CB)‐based MU‐MIMO feedback scheme. The objective of this paper is to verify such a scheme's performance under a practical system configuration with a 3D channel model in various radio environments. We evaluate the performance of various CB‐based feedback schemes with different types of overhead reduction approaches, providing an experimental ground with which to optimize a CB‐based MU‐MIMO feedback scheme while identifying the design constraints for a massive MIMO system.     

XML-based concurrent and integrated ergonomic analysis in PLM

In this paper, finding the maximum dynamic load carrying capacity of flexible joint manipulators in point-to-point motion is formulated as an optimal control problem. The computational methods are classified as indirect and direct methods. This work is based on the indirect solution method of optimal control problem. The application of Pontryagin’s minimum principle to this problem results in a two-point boundary value problem (TPBVP) solved numerically. Two algorithms are developed on the basis of the solution of the TPBVP. The first one is used to plan the optimal path for a given payload, and the other one is exploited to find the maximum payload and corresponding optimal path. The main advantage of the proposed method is that the various optimal trajectories are obtained with different characteristics and different maximum payload. Therefore, the designer can select a suitable path among the numerous optimal paths. In order to illustrate the power and efficiency of the proposed method in the presence of flexibility in joints, a number of simulation tests are performed for a two-link manipulator. Then, the effect of flexibility on the maximum payload value is investigated and compared with rigid one. Finally, for the sake of comparison with previous results in the literature, simulation is performed for a rigid-joint three-link manipulator, and a reasonable agreement is observed between the results.     

Development of a maritime transportation planning support system for car carriers based on genetic algorithm

Recently, the port logistics market is rapidly expanding, along with the active maritime trade. To adjust to this trend and gain a competitive advantage, competition among shipping companies at home and abroad has intensified, and many efforts are being made for the improvement of customer services and cost saving. In particular, car carriers transporting more than 80% of total car import/export volume must quickly make efforts to reduce transportation costs. Much research has been conducted to improve the efficiency of maritime transportation, but studies on car carriers, which are given relatively less importance, have been lacking. The car carrier’s transportation planning is similar to the vehicle routing problem, but it is much more complicated in that cars and cargo are prepared at different points in time, and cargo can be loaded not only at the departing port but also at other ports. Therefore, in an effort to solve the problem, this study has developed a meta-heuristic algorithm based on a genetic algorithm, and we have succeeded in developing a maritime transportation planning support system with the algorithm, thus making it possible to prepare various alternatives, evaluate them, and consequently support user’s decision making.     

Spatial distributions of ozonolysis products from human surfaces in ventilated rooms

Ozone has adverse effects on human health. Skin oil on the human surface acts as an ozone sink indoors, producing oxidation products that can cause skin and respiratory irritations. Concentrations of ozone and oxidation products near human surfaces, including the breathing zone, can be modulated by indoor ventilation modes and human surface conditions. The objective of this study is to examine concentrations and spatial heterogeneity of ozone and ozonolysis products under representative ranges of indoor ventilation, clothing, and breathing conditions. Using computational fluid dynamics (CFD) simulation in conjunction with a chemical kinetic model, details of ozone reactions with the human surface and subsequent chemical reactions are examined. The results show that primary ozonolysis products are concentrated near the soiled clothing, while the secondary products are relatively well distributed throughout the room. Increasing indoor air mixing enhances the ozone deposition to the human surface, thereby resulting in higher emission rates of oxidation products in the room. Soiled clothing consumes more ozone than clean clothing and accordingly produces ~ 65% more primary products and ~15% more secondary products. The results also reveal that unsaturated hydrocarbons from the human breath, such as isoprene, contribute to only ~0.5% of ozone removal compared to ozone deposition to the human surface.     

Does Curcuma longa root powder have an effect against CCl4-induced hepatotoxicity in rats: a protective and curative approach

Food Science and Biotechnology - This study was conducted to investigate potentially protective and curative effects of Curcuma longa root (turmeric) powder on CCl4-induced hepatotoxicity in rats....     

Effective hole‐injection characteristics of organic light‐emitting diodes due to fluorinated self‐assembled monolayer embedded as a buffer layer

The electrical and optical properties of organic light‐emitting diodes (OLEDs) are demonstrated by varying the length of the alkyl chain of a fluorinated self‐assembled monolayer (F‐nSAM). OLEDs containing F‐nSAMs that have a long alkyl chain length were found to exhibit excellent properties in terms of current density, luminance, turn‐on voltage, etc. The obtained current density at 6 V, which was the highest measurement voltage, was up to about 36 times higher for an OLED including an F‐12SAM thin film with the longest chain length than for an OLED including only an indium tin oxide (ITO) substrate. With regard to luminance characteristics depending on voltage, the luminance was about 13 times higher for the OLED including the F‐12SAM thin film than for the OLED including only the ITO substrate. Also, the turn‐on voltage of the OLED including the F‐12SAM thin film was decreased by approximately 1 V compared to that of the OLED including only the ITO substrate. Although F‐nSAMs with alkyl chains have insulating film properties, F‐nSAMs with long alkyl chains exhibited good electrical and optical properties because of an improvement in the hole‐injection barrier due to a large positive shift of the vacuum level and smooth carrier injection resulting from a high contact angle due to strong hydrophobic properties caused by the good alignment properties of F‐nSAMs resulting from strong van der Waals forces between the molecules due to the long alkyl chains. © 2019 Society of Chemical Industry