Reconfigurable Circularly Polarized Microstrip Antenna on a Slotted Ground

A compact square patch antenna with reconfigurable circular polarization (CP) at 2.4 GHz is proposed. Circular polarization is generated by an arc‐shaped slot on the ground plane. In order to switch the CP orientation, the current flow direction of the patch is reconfigured via the PIN diodes mounted on the slot. As the slot and bias circuit are not placed on the patch side, the proposed antenna radiates a CP wave without alteration in the main beam direction. From the experimental results, the impedance and CP bandwidths of the proposed antenna have been demonstrated for up to 80 MHz and 25 MHz, respectively.     

RFID Tag Antenna Coupled by Shorted Microstrip Line for Metallic Surfaces

This letter presents the design of a small and low‐profile RFID tag antenna in the UHF band that can be mounted on metallic objects. The designed tag antenna, which uses a ceramic material as a substrate, consists of a radiating patch and a microstrip line with two shorting pins for a proximity‐coupled feeding structure. Using this structure, impedance matching can be simply obtained between the antenna and tag chip without a matching network. The fractional impedance bandwidth for S₁₁<3 dB and radiation efficiency are about 1.4% and 56% at 911 MHz, respectively. The read range is approximately from 5 m to 6 m when the tag antenna is mounted on a metallic surface.     

Improvement of testosterone deficiency by fermented Momordica charantia extracts in aging male rats

This study evaluated the efficacy of Momordica charantia (MC; bitter melon) extracts against andropause symptoms. We fermented MC with Lactobacillus plantarum and verified the ability of the fermented MC extracts (FMEs) to control testosterone deficiency by using aging male rats as an animal model of andropause. FME administration considerably increased total and free testosterone levels, muscle mass, forced swimming time, and total and motile sperm counts in aging male rats. In contrast, sex hormone-binding globulin, retroperitoneal fat, serum cholesterol, and triglyceride levels were significantly reduced in the treated groups compared to the non-treated control aging male rats. Furthermore, we observed that FME enhanced the expression of testosterone biosynthesis-related genes but reduced the expression of testosterone degradation-related genes in a mouse Leydig cell line. These results suggest that FME has effective pharmacological activities that increase and restore free testosterone levels and that FME may be employed as a promising natural product for alleviating testosterone deficiency syndrome.Supplementary InformationThe online version contains supplementary material available at 10.1007/s10068-020-00872-x.     

Phospholipids as cancer biomarkers: Mass spectrometry‐based analysis

Lipids, particularly phospholipids (PLs), are key components of cellular membrane. PLs play important and diverse roles in cells such as chemical‐energy storage, cellular signaling, cell membranes, and cell–cell interactions in tissues. All these cellular processes are pertinent to cells that undergo transformation, cancer progression, and metastasis. Thus, there is a strong possibility that some classes of PLs are expected to present in cancer cells and tissues in cellular physiology. The mass spectrometric soft‐ionization techniques, electrospray ionization (ESI), and matrix‐assisted laser desorption/ionization (MALDI) are well‐established in the proteomics field, have been used for lipidomic analysis in cancer research. This review focused on the applications of mass spectrometry (MS) mainly on ESI‐MS and MALDI‐MS in the structural characterization, molecular composition and key roles of various PLs present in cancer cells, tissues, blood, and urine, and on their importance for cancer‐related problems as well as challenges for development of novel PL‐based biomarkers. The profiling of PLs helps to rationalize their functions in biological systems, and will also provide diagnostic information to elucidate mechanisms behind the control of cancer, diabetes, and neurodegenerative diseases. The investigation of cellular PLs with MS methods suggests new insights on various cancer diseases and clinical applications in the drug discovery and development of biomarkers for various PL‐related different cancer diseases. PL profiling in tissues, cells and body fluids also reflect the general condition of the whole organism and can indicate the existence of cancer and other diseases. PL profiling with MS opens new prospects to assess alterations of PLs in cancer, screening specific biomarkers and provide a basis for the development of novel therapeutic strategies. © 2016 Wiley Periodicals, Inc. Mass Spec Rev 37:107‐138, 2018     

Development of Selective Electroless-Deposited Electrode in Heterojunction with Intrinsic Thin-Layer Solar Cell

In this paper, we describe selective deposition of a major electrode and a protection electrode in a heterojunction with intrinsic thin-layer (HIT) type solar cell. Sn and Ni were used for the protection electrode to prevent the oxidation of Cu, which was used for the main electrode. SEM and TEM were used to analyze the microstructural evolution and changes in the interface as a result of each electroless deposition. Finally, the performance of our solar cell created via electroless deposition was evaluated. We determined the photovoltaic conversion efficiency (PCE) to be 16.4 %, the fill factor (FF) to be 72.2 %, the open circuit voltage (Voc) to be 681 mV, and the short circuit current (Jsc) to be 33.0 mA/cm². These output values match the performance of an Ag screen-printed solar cell and demonstrate the possibility of commercializing an inexpensive HIT solar cell with high efficiency.     

Phenolic constituents from the flower buds of Lonicera japonica and their 5-lipoxygenase inhibitory activities

Thirteen phenolic constituents, luteolin (1), protocatechuic acid (2), caffeic acid (3), flavoyadorinin-B (4), 4,5-dicaffeoylquinic acid (5), luteolin 7-O-β-d-glucopyranoside (7), 3,5-dicaffeoylquinic acid methyl ester (8), methyl chlorogenate (9), quercetin 3-O-β-d-glucopyranoside (10), 3,5-dicaffeoylquinic acid (11), rhoifolin (12), chlorogenic acid (13), and a novel phenolic glucoside benzoate, vanillic acid 4-O-β-d-(6-O-benzoylglucopyranoside) (6), were isolated from the flower buds of Lonicera japonica. Flavoyadorinin-B (4) was isolated for the first time from a Caprifoliaceae plant. The structures of 1–13 were determined on the basis of chemical and spectroscopic evidence. These compounds were screened for their 5-lipoxygenase inhibitory activity. Only luteolin (1) showed significant inhibitory activity against 5-LOX-catalysed leukotriene production.     

Predictors of glass transition in the biodegradable poly‐lactide and poly‐lactide‐co‐glycolide polymers

The biodegradable polylactide (PLA) and polylactide‐co‐glycolides (PLGAs) are being widely investigated for use as scaffolds in bone and ligament reconstruction. The glass transition temperatures (T_g) for these polymers are generally greater than 37°C, causing PLA and PLGA devices to possess brittle characteristics in physiological conditions. To evaluate the possibility of obtaining PLGA polymers with T_g values below 37°C, we evaluated the determinants of T_g in PLA and PLGA copolymers. The T_g, changes in specific heat capacity (ΔC_p), and enthalpic relaxation (ΔH_g) in two consecutive heating cycles were correlated with lactide/glycolide content and intrinsic viscosity [η] for PLA, PLGAs 90:10, 75:25, 65:35, and 50:50. A linear correlation was observed between T_g and intrinsic viscosity, with 0.1 dL/g increase in viscosity resulting in an increase in T_g by about 3.55°C. The selection of PLA and PLGA copolymers with [η] values <0.19 dL/g, corresponding to a viscosity average molecular weight of <70 kDa, will obtain PLA/PLGA polymers with T_g values below 37°C. The lowest attainable T_g values were found to be 28–30°C. Intrinsic viscosity also correlated with ΔC_p differences between aged and rapidly cooled polymers, and is therefore important in predicting free volume changes within these polymers upon aging. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1983–1987, 2006     

Mode II fracture mechanisms of PBT-modified brittle epoxies

Mode II fracture behavior of poly(butylene terephthalate) (PBT)-modified epoxy systems are studied. Two different types of testing for mode II fracture are conducted. One was to investigate the fracture behavior of bulk epoxy systems, in comparison with mode I fracture, using single-edge notched specimens under skew symmetric four-point loading. The other was to investigate the fracture behavior of epoxy layers sandwiched between aluminium adherends using compact shear specimens. The mode II fracture toughness obtained from the former for modified systems has been found to increase significantly over the control, although the increase of mode I fracture toughness for modified systems over the control is moderate. This finding is discussed in relation with cavitation and equivalent mode I stress intensity factor and also in comparison with rubber-modified epoxy systems in the literature to account for the increase. In addition, the difference in fracture morphology between mode I and II is discussed. Mode II fracture toughness obtained from the latter for modified systems has also been found to increase significantly over the control. Morphology of fracture surfaces relating to this finding is discussed. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 405–415, 1998     

Flexible and Waterproof Resistive Random‐Access Memory Based on Nitrocellulose for Skin‐Attachable Wearable Devices

Memory for skin‐attachable wearable devices for healthcare monitoring must meet a number of requirements, including flexibility and stability in external environments. Among various memory technologies, organic‐based resistive random‐access memory (RRAM) devices are an attractive candidate for skin‐attachable wearable devices due to the high flexibility of organic materials. However, organic‐based RRAMs are particularly vulnerable to external moisture, making them difficult to apply as skin‐attachable wearable devices. In this research, RRAMs are fabricated that meet the requirements for skin‐attachable wearable devices using a novel organic material, nitrocellulose (NC), which is biocompatible with high water‐resistance and high flexibility. The fabricated NC‐based RRAMs show a stable bipolar resistive switching characteristic. In addition, the formation of a native Al oxide between Al and NC is verified, which is the source of the bipolar switching characteristic of NC‐based RRAMs. Furthermore, electrical and chemical analysis is conducted after dipping and submersion into various solutions as well as deionized water to confirm the water‐resistance of the NC‐based RRAMs. Finally, it is also confirmed that NC‐based RRAMs are suitable for use in skin‐attachable wearable devices through a flexibility test. In conclusion, this study suggests that NC‐based RRAMs can be applied in skin‐attachable wearable devices, simplifying healthcare in the future.