A 0.9 V 92 dB Double-Sampled Switched-RC Delta-Sigma Audio ADC

A 0.9 V third-order double-sampled delta-sigma audio ADC is presented. A new method using a combination of a switched-RC technique and a floating switched-capacitor double-sampling configuration enabled low-voltage operation without clock boosting or bootstrapping. A three-level quantizer with simple dynamic element matching was used to improve linearity. The prototype IC implemented in a 0.13 CMOS process achieves 92 dB DR, 91 dB SNR and 89 dB SNDR in a 24 kHz audio signal bandwidth, while consuming 1.5 mW from a 0.9 V supply. The prototype operates from 0.65 V to 1.5 V supply with minimal performance degradation.     

Apoptotic Effects of Anthocyanins from Vitis coignetiae Pulliat Are Enhanced by Augmented Enhancer of the Rudimentary Homolog (ERH) in Human Gastric Carcinoma MKN28 Cells

Evidence suggests that augmented expression of a certain gene can influence the efficacy of targeted and conventional chemotherapies. Here, we tested whether the high expression of enhancer of the rudimentary homolog (ERH), which serves as a prognostic factor in some cancers, can influence the efficacy of anthocyanins isolated from fruits of Vitis coignetiae Pulliat, Meoru in Korea (AIMs) on human gastric cancer cells. The anticancer efficacy of AIMs was augmented in ERH-transfected MKN28 cells (E-MKN28 cells). Molecularly, ERH augmented AIM-induced caspase-dependent apoptosis by activating caspase-3 and -9. The ERH-augmented apoptotic effect was related to mitochondrial depolarization and inhibition of antiapoptotic proteins, XIAP, and Bcl-2. In addition, reactive oxygen species (ROS) generation was augmented in AIMs-treated E-MKN28 cells compared to AIMs-treated naïve MKN28 cells. In conclusion, ERH augmented AIM-induced caspase-dependent mitochondrial-related apoptosis in MKN28 cells. A decrease in expression of Bcl-2 and subsequent excessive ROS generation would be the mechanism for ERH-augmented mitochondrial-related apoptosis in AIMs-treated MKN28 cells. A decrease in expression of XIAP would be another mechanism for ERH-augmented caspase-dependent apoptosis in AIMs-treated MKN28 cells.     

The effect of hydrogen bonding on the phase behavior of poly(ethylene-co-acrylic acid)-ethylene-cosolvent mixtures at high pressures

Experimental cloud-point data to 260 °C and 2,500 bar are reported to demonstrate the impact of two cosolvents, acetone and methanol, on the phase behavior of polyethylene, poly(ethylene-co-2.4 mol% acrylic acid) (EAA_2.4), poly(ethylene-co-3.9 mol% acrylic acid) (EAA_3.9), poly(ethylene-co-6.9 mol% acrylic acid) (EAA_6.9), and poly(ethylene-co-9.2 mol% acrylic acid) (EAA_9.2) in ethylene. In pressure-temperature (P-T) space, the miscibility of EAA copolymers in ethylene decreases significantly with temperature and with increasing acrylic acid content of EAA due to self-association of the acrylic acid segments. Acetone and methanol, both dramatically enlarge the solubility of EAA copolymers due to the hydrogen bonding with acrylic acids in the EAA. At low concentrations, methanol is a better cosolvent than acetone. However, the impact of methanol diminishes rapidly with increasing methanol concentration once all the acrylic acids in the EAA are hydrogen bond with methanol molecules.     

Ultrasonic spray pyrolysis of nano crystalline spinel LiMn2O4 showing good cycling performance in the 3 V range

Spherical lithium manganese oxide spinel was synthesized by an ultrasonic spray pyrolysis method, and has been characterized using X-ray diffraction, scanning electron microscopy, transimission electron microscopy and electrochemical cycling at 3 V regions. The LiMn₂O₄ powders were composed of about 10 nm-sized primary particles. The delivered discharge capacity of the synthesized nano-material was 125 mAh g⁻¹ between 2.4 and 3.5 V and its retention was about 96% upon 50 cycling. From the high resolution transmission electron microscopic study, it was found that structural transition of the parent material did not occur even after the 50th electrochemical cycling on the 3 V region. It seems that the reversible structural change is possible for nanocrystalline LiMn₂O₄ as observed by the X-ray diffraction and transition electron microscopic observations.     

Blood flow interpretation in femoral pseudoaneurysm

A femoral artery pseudoaneurysm is one complication of vascular intervention, and the incidence is increasing. Early management is then needed to avoid potential dangers from it. It differs from a true aneurysm in that it doesn＇t include any component of the vascular wall, and is not studied as much as a true aneurysm. Here, a model of a femoral pseudoaneurysm was made and a Computational Fluid Dynamics（CFD） simulation was verified with PIV experiment. Afterwards, a CFD simulation with two different models was performed to look for any findings which may help in developing new treatment methods.     

Effect of nanoparticle surface functionality on microdomain orientation in block copolymer thin films under electric field

The electric field induced microdomain orientations has been an interesting research topic. In this article, the effect of nanoparticle surface functionality on microdomain alignments in block copolymer/nanoparticle hybrid thin films was investigated with transmission electron microscopy experiments. The presence of gold nanoparticles influenced the microdomain orientation behaviors of block copolymer/nanoparticle thin films. The possibility for complete alignment normal to the substrate was illustrated by controlling electric field strength, concentration, and surface ligands of nanoparticles. This work provides basic and essential data to understand the properties and behaviors of emerging block copolymer/nanoparticle hybrid thin films.     

Production and Characterization of Branched Oligosaccharides from Liquefied Starch by the Action of B. Licheniformis Amylase

A branched oligosaccharides (BOS) mixture was produced from liquefied starch solution using a maltogenic amylase of Bacillus licheniformis (BLMA). The BOS mixture was produced by both α-1,4-bond hydrolyzing and α-1,6-transglycosylation activities of BLMA, and it contained 58.3% of various branched oligosaccharides. Small branched oligosaccharides such as isomaltose, isopanose, and panose were identified in the mixture by various analyses including high performance ion-chromatography (HPIC). Major branched DP4 and DP5 molecules in the mixture were determined as 6²-O-α-maltosylmaltose, 6³-O-α-maltosyl-maltotriose and 6²-O-α-maltotriosyl-maltose, respectively. Time course study of BOS production suggested that the hydrolysis and transglycosylation reactions catalyzed by BLMA were coupled. BLMA was likely to transfer a sugar moiety hydrolyzed from a non-reducing end of maltooligosaccharide, mainly maltose, to another moiety of sugar via the formation of α-1,6-linkage. Immobilization of BLMA was attempted as an effort to achieve a continuous process for BOS production. the immobilized enzyme showed improved thermal stability and slight loss of enzyme activity was observed during repeated usage.     

Simvastatin Attenuates the Oxidative Stress,Endothelial Thrombogenicity and the Inducibility of Atrial Fibrillation in a Rat Model of Ischemic Heart Failure

Increased atrial oxidative stress has an important role in inducing and maintaining atrial fibrillation (AF), and the activation of the small GTPase Rac1 contributes to the oxidative stress. We investigated the relationship of Rac1, atrial endothelial thromboprotective markers and AF inducibility and if simvastatin has a potential beneficial effect on a myocardial infarction (MI)-induced heart failure (HF) rat model. Rats were randomized into three groups (shams, MI group and simvastatin treatment group) and underwent echocardiography, AF induction studies and left atrial (LA) fibrosis analysis. Atrial Rac 1, sodium calcium exchanger (I_NCX), sarcoplasmic reticulum calcium ATPase (SERCA), endothelial nitric oxide synthase (eNOS) and induced nitric oxide synthase (iNOS) were measured. AF inducibility, AF duration and LA fibrosis were significantly higher in the MI group (p < 0.001 vs. sham), which were significantly reduced by simvastatin (p < 0.05 vs. MI). The reduced expressions of atrial eNOS, SERCA, thrombomodulin, tissue factor pathway inhibitor and tissue plasminogen activator in the MI group were significantly improved by simvastatin. Furthermore, the increased expression of atrial iNOS, I_NCX and Rac1 activity were significantly decreased by the simvastatin. Oxidative stress, endothelial dysfunction and thrombogenicity are associated with the promotion of AF in a rat model of ischemic HF. These were associated with increased Rac1 activity, and simvastatin treatment prevents these changes.     

Low-temperature mechanical properties of superconducting radio frequency cavity materials

Low-temperature mechanical behaviors have been investigated for the constituent materials of superconducting radio frequency cavities. Test materials consist of small grain Nb, single crystal Nb, large grain Nb (bicrystal), Ti45Nb-Nb weld joint (e-beam welded), and Ti-316L bimetal joint (explosion welded). The strength of all test metals displayed strong temperature dependence and the Ti-316L bimetal showed the highest strength and lowest ductility among the test materials. The fracture toughness of the small grain Nb metals decreased with decreasing test temperature and reached the lower shelf values (30-40 MPa √m) at or above 173 K. The Ti45Nb base and Ti45Nb-Nb weld metals showed much higher fracture toughness than the small grain Nb. An extrapolation and comparison with existing data showed that the fracture toughness of the small grain Nb metals at 4 K was expected to be similar to those at 173 and 77 K. The results from optical photography at a low magnification and fractography by a scanning electron microscope were consistent with corresponding mechanical properties.