The optimum dose of gamma radiation–heavy doses to low wear polyethylene in total hip prostheses

Wear volume, surface area and coefficient of friction of UHMWPE cup crosslinked with gamma radiation of 0, 50, 75, 100, 125, 150 and 200 Mrad sliding against an alumina ball were measured using a sphere-on-flat reciprocating type tribology testing machine. The effects of gamma radiation were scarcely observed in coefficient of friction. The coefficient of friction under lubricated (distilled water) and non-lubricated testing conditions was 0.08 to 0.12 and 0.20 to 0.25, respectively. The wear volume of UHMWPE with radiation of 50 Mrad, 75 to 150 Mrad, and 200 Mrad was 70 to 80%, 18 to 25%, and 12 to 15%, respectively, in comparison to non-irradiated specimens. Elongation and tensile strength of UHMWPE with radiation of 100 Mrad decreased to 6%, and 50% of that without radiation, respectively. The hardness increased with increase of the radiation dose. From several kinds of tribological findings, mechanical strength tests, and studies of long-term clinical findings, it is concluded that approximately 200 Mrad is the optimum dose of gamma radiation for clinical use in total hip prostheses.     

Secretome-microRNA and anti-proliferative APRO family proteins as cancer prevention and stem cell research strategies

Stemness of cancer cells contains limitless self-renewal proliferation. For the purpose of proliferation, secretome might exert its effects via the paracrine signaling. Specific microRNAs enclosed in the secretome of cancer stem cells could regulate the expression of anti-proliferative APRO family proteins. The biological functions of APRO family proteins seems to be quite intricate, however, which might be a key modulator of microRNAs, then could regulate the proliferation of cancer cells. In addition to affecting proliferation/differentiation during cellular development, APRO family proteins might also play an imperious role on keeping homeostasis in healthy stem cells under a physiological condition. Therefore, relationship between the microRNAs and the APRO family proteins has attracted much attention in the field of cancer research and regenerative medicine. Here, we have described the molecular mechanism behind this interplay that have a potential role in the future promising tools with targeting APRO family proteins for the medical applications.     

INTERNATIONAL COOPERATIVE COMPARISON OF INSTRUMENT METHODS FOR COOKED RICE TEXTURE

The texture of 10 milled rices cooked by a standardized method in excess water was measured in 11 laboratories using various instrument methods that had been developed specifically for national samples. The samples selected represented a wide range of rice textures. Instrument indexes for hardness and stickiness of cooked rice generally were more sensitive than the corresponding taste panel scores in discriminating among the 10 cooked rice samples. Instrument indexes for hardness correlated positively among each other as did those for stickiness. Most hardness indexes showed significant negative correlation with stickiness indexes. Most hardness indexes were positively correlated with amylose content whereas stickiness indexes were negatively correlated with amylose content. The continued use of amylose content as an index of eating quality in a rice breeding program is justified.     

Mesenchymal stem cells-derived extracellular vesicles as ‘natural’ drug delivery system for tissue regeneration

Mesenchymal stem cells (MSCs) have abilities to mediate tissue protection through mechanisms of anti-apoptosis, anti-oxidative stress and anti-fibrosis as well as tissue regeneration through mechanisms of cell proliferation, differentiation and angiogenesis. These effects by MSCs are mediated by a variety of factors, including growth factors, cytokines and extracellular vesicles (EVs). Among these factors, EVs, containing proteins, mRNA and microRNAs (miRNA), may carry their contents into distant tissues with high stability. Therefore, the treatment with MSC-derived EVs may be promising as ‘natural’ drug delivery systems (DDS). Especially, the treatment of MSC-derived EVs with the manipulation of specific miRNAs expression has been reported to be beneficial under a variety of diseases and tissue injuries. The overexpression of specific miRNAs in the EVs might be through pre-loading method using the gene editing system by plasmid vector or post-loading method to load miRNA mimics into EVs by electroporation or calcium chloride-mediated transfection. Despite current several challenges for clinical use, it should open the next era of regenerative medicine for a variety of diseases. In this article, we highlight the therapeutic potential of MSC-derived EVs as ‘natural’ DDS and current challenges.     

基于液晶引流效应的微流体驱动方式开发

以开发全新微流体驱动与控制方式为目标,运用液晶弹性形变理论与Leslie-Ericksen理论,对两平行板内电场引起的液晶流动进行研究。理论计算中主要讨论了扭转角对流动剖面图的影响:扭转角对流动的空间特征量影响较大,对于时间特征量没有影响。实验中采用5 V低电压驱动,通过向液晶混入极少量微粒子观察流动的特性,结果与理论计算结果较吻合。     

Electron microscopy and diffraction of radiation-sensitive nanostructured materials

Soft matter research of natural organic and synthetic nanomaterials is an area in nanoscience and technology that has been growing particularly quickly in recent years. The materials under investigation are sensitive to high‐energy electrons. Any structure characterization using electron microscopy thus requires special care. First, we illustrated this on naturally grown nanotubes observed by normal and cryogenic scanning electron microscopy. Second, we studied the ordering and orientation of the mesophase in template‐grown nanotubes and nanorods containing discotic liquid crystals without and with doping, as desired. For these studies, we mainly used transmission electron diffraction and microscopy at low‐dose conditions, high‐efficiency image acquisition, and cryoprotection of the structures at liquid helium temperature. Additional analytical information was obtained by electron energy filtering observations.     

SYNTHETIC INORGANIC ION-EXCHANGE MATERIALS XXXVI. SYNTHESIS OF CRYPTOMELANE-TYPE HYDROUS MANGANESE DIOXIDE AS AN ION-EXCHANGE MATERIAL AND THEIR ION-EXCHANGE SELECTIVITIES TOWARDS ALKALI AND ALKALINE EARTH METAL IONS

Abstract

Hydrous manganese dioxide in a cryptomelane-type showed an excellent ion-exchange selectivity for K⁺, Rb⁺and Ba²⁺ ions having the effective ionic radii of about 1.4 Å. Log-log plots of distribution coefficients for alkali and alkaline earth metal ions vs. [HNO₃] yielded a straight line with a slope of ?1 and ?2, respectively, indicating the “ideal” ion-exchange mechanism. The stoichiometry of ion-exchange reactions was also established for the uptake of macro-amounts of alkali metal ions in nitrate media.     

Conditioning of Meat with Raw Soy Sauce and Its Proteinases: Their Effects on the Quality of Beef

This investigation demonstrated that raw soy sauce added to beef in the process of tenderization was effective in improving its sensory quality. To estimate the contributions of proteinases occurring in the raw soy sauce, the degradation of myofibril and collagen was investigated by using the inhibitors, potato inhibitor, ethylenediaminetetraacetic acid (EDTA) and pepstatin which inhibit serine-, metallo-, and aspartic proteinases, respectively. A serine proteinase was most greatly involved in the degradations of both myofibril and collagen. Electrophoretic patterns of myofibril degraded by a purified serine proteinase coincided well with those of myofibril treated with the raw soy sauce per se.     

Estimation and Kinetic Modeling of Human Arm using Wearable Robot Arm

This paper describes an estimation method for the physical parameters of human arms. The parameters are used in the medical and kinematic analysis fields. Personal differences are important, but some of the conventional methods do not consider personal differences pertaining to inertia in viscoelasticity muscular strength measurements. The remaining conventional methods that consider personal differences require precise measurement devices. The proposed method realizes kinetics modeling and identification of the friction and inertia including the off‐diagonal parameters of human arms by using wearable robots. First, wearable robots are multi‐input devices. In addition, the actuators of wearable robots can be located near human joints and can input M‐sequence torque. Therefore, wearable robots can input signals having a high signal‐to‐noise ratio and ensuring persistently exciting characteristics in each human joint. By employing multi‐input characteristics, the proposed method can reduce patients’ burden by shortening the amount of time for estimation. In addition, we verify the accuracy of the estimated parameters by comparing the responses of the actual machine with those obtained by simulation.