Chemical composition and antioxidant properties of the essential oil and methanol extracts of rhizoma Alpinia officinarum from China in vitro

This study was designed to examine the in vitro antioxidant activities of the essential oil and methanol extracts of rhizoma Alpinia officinarum (small galanga) from China. The essential oil was analyzed by gas chromatography/ mass spectrometry (GC/MS) and 46 constituents were identified. Methanol extract from rhizoma A. officinarum was fractionated by chromatography of silica gel using ethyl acetate, acetone-methanol (8:1, V/V) and methanol, respectively. The antioxidant activities of essential oil and methanol extracts were evaluated with reducing power, diphenylpicrylhydrazyl (DPPH) assay and ferric thiocyanate test. In the above three assays, the essential oil and methanol extracts showed antioxidant potential to varying degrees; and acetone-methanol (8:1, V/V) subfraction exhibited better antioxidant potency than others. Owing to having antioxidative components, the essential oil exhibited satisfying antioxidant activities. A positive correlation was observed between the antioxidant activity potential and total phenolic contents of the extracts

Temperature dependence of electron-spin relaxation in a single InAs quantum dot at zero applied magnetic field

The temperature-dependent electron spin relaxation of positively charged excitons in a single InAs quantum dot (QD) was measured by time-resolved photoluminescence spectroscopy at zero applied magnetic fields. The experimental results show that the electron-spin relaxation is clearly divided into two different temperature regimes: (i) T < 50 K, spin relaxation depends on the dynamical nuclear spin polarization (DNSP) and is approximately temperature-independent, as predicted by Merkulov et al. (ii) T > about 50 K, spin relaxation speeds up with increasing temperature. A model of two LO phonon scattering process coupled with hyperfine interaction is proposed to account for the accelerated electron spin relaxation at higher temperatures.Comment: 10 pages, 4 figure

S4ND: Single-Shot Single-Scale Lung Nodule Detection

The state of the art lung nodule detection studies rely on computationally expensive multi-stage frameworks to detect nodules from CT scans. To address this computational challenge and provide better performance, in this paper we propose S4ND, a new deep learning based method for lung nodule detection. Our approach uses a single feed forward pass of a single network for detection and provides better performance when compared to the current literature. The whole detection pipeline is designed as a single $3D$ Convolutional Neural Network (CNN) with dense connections, trained in an end-to-end manner. S4ND does not require any further post-processing or user guidance to refine detection results. Experimentally, we compared our network with the current state-of-the-art object detection network (SSD) in computer vision as well as the state-of-the-art published method for lung nodule detection (3D DCNN). We used publically available $888$ CT scans from LUNA challenge dataset and showed that the proposed method outperforms the current literature both in terms of efficiency and accuracy by achieving an average FROC-score of $0.897$. We also provide an in-depth analysis of our proposed network to shed light on the unclear paradigms of tiny object detection.Comment: Accepted for publication at MICCAI 2018 (21st International Conference on Medical Image Computing and Computer Assisted Intervention

Multi-functional fluorescent carbon dots with antibacterial and gene delivery properties

Glucose is abundant in nature and can be found in various sources. In this study, we developed multifunctional carbon dots (CDs) with glucose, and poly(ethyleneimine) (PEI) which were further quaternized using a facile approach. The CDs are designed to possess both antibacteria and gene delivery capabilities. The inherent property was characterized with TEM, NMR, FTIR and fluorescent spectroscopy. Antibacterial activity was evaluated with Broth minimum inhibitory concentration (MIC) assay on both gram-positive and gram-negative bacteria. The CDs showed excellent inhibitation to both bacteria. The expression of CDs condensed plasmid DNA in HEK 293T cells was investigated with Luciferase expression assay. Gene transfection capability of the quaternized CDs was found to be up to 104 times efficient than naked DNA delivery

Ambient Aqueous Growth of Cu2Te Nanostructures with Excellent Electrocatalytic Activity toward Sulfide Redox Shuttles.

A new aqueous and scalable strategy to synthesize surfactant-free Cu2Te nanotubes and nanosheets at room temperature has been developed. In aqueous solution, Cu2E (E = O, S, Se) nanoparticles can be easily transformed into Cu2Te nanosheets and nanotubes via a simple anion exchange reaction under ambient conditions. The formation of Cu2Te nanosheets is ascribed to a novel exchange-peeling growth mechanism instead of simple Kirkendall effect; and the resultant nanosheets can be further rolled into nanotubes with assistance of stirring. The morphologies of Cu2Te nanosheets and nanotubes can be easily controlled by changing the synthesis parameters, such as the concentration of precursors, the size of nanoparticle precursor, and the amount of NaBH4, as well as the stirring speed. Thus-formed Cu2Te nanostructures exhibit excellent catalytic activity toward sulfide redox shuttles and are exploited as counter electrodes catalysts for quantum dot sensitized solar cells. The performance of Cu2Te nanostructures strongly depends on their morphology, and the solar cells made with counter electrodes from Cu2Te nanosheets show the maximum power conversion efficiency of 5.35%

Measurements of a fast nuclear spin dynamics in a single InAs quantum dot with positively charged exciton

By using highly time-resolved spectroscopy with an alternative {\sigma}+/{\sigma} - laser pulse modulation technique, we are able to measure the fast buildup and decay times of the dynamical nuclear spin polarization (DNSP) at 5 K for a single InAs quantum dot (QD) with positively charged exciton. It is shown that the nuclear dipole-dipole interaction can efficiently depolarize DNSP with a typical time constant of 500 {\mu}s in the absence of external magnetic field. By using an external field of 8 mT to suppress the nuclear dipolar interaction, the decay time turns to be mainly induced by interaction with unpaired electron and extends to about 5 ms. In addition, it is found that the time constant of hole-induced depolarization of nuclear spin is about 112 ms.Comment: 5 pages, 3 figure

An association study between polymorphism of alcohol dehydrogenase (ADH1B), aldehyde dehydrogenase (ALDH2), cytochrome (CYP4502E1), Catechol-OMethyltransferase (COMT) and 5-hydroxytryptamine transporter (5-HTT)...

Full Title: An association study between polymorphism of alcohol dehydrogenase (ADH1B), aldehyde dehydrogenase (ALDH2), cytochrome (CYP4502E1), Catechol-OMethyltransferase (COMT) and 5-hydroxytryptamine transporter (5-HTT) genes in Yunnan Han population with alcohol dependenceAbstact: Alcohol dependence (AD) is a complex disease resulting from the inheritance of several susceptible genes and multiple environmental determinants. The aim of this study was to identify the genetic risk factors which include alcohol metabolizing genes and neurotransmitter related genes for alcoholism in Yunnan Han population. Eight allelic variants of five genes were genotyped from 332 Yunnan Han individuals (including 118 alcohol-dependent patients (DSM-IV criteria) and 214 controls) using PCRRFLP method. Those polymorphic sites included alcohol dehydrogenase (ADH1B), aldehyde dehydrogenase (ALDH2), cytochrome P-4502E1 (CYP2E1) PstI, Catechol-O-Methyltransferase (COMT) rs2075507 (5’region), rs737865 (intron1), rs4680 (Val158Met), rs165599 (3’region) and serotonin transporter (5-HTTLPR). Both genotype and allele frequencies of ALDH2 and CYP4502E1 as well as the allele frequency of ADH1B gene differed significantly between AD group and control group. The proportion of ALDH2 *1/*2 genotype and *2 allele was significantly smaller in patients than that in controls (X2 = 6.554, p = 0.038; X2 = 4.906, p = 0.027), while the proportion of c2 allele of CYP4502E1 was significantly higher (X2 = 4.410, p = 0.036). Compared with the controls, the frequencies of the 5-HTTLPR L/L genotype and COMT rs737865 C/C genotype were significantly lower in AD group. Twelve COMT haplotypes (rs2075507, rs737865, rs4680 and rs165599) defined as H1 to H12 were obtained in this major minority population. The prevalence of the haplotype H1 ‘‘A-C-A-A’’ was significantly greater in alcoholics than the prevalence in their respective control group. There were no significant differences in the genotype frequencies of the COMT rs2075507, rs4680 and rs165599 polymorphisms between alcoholics and controls. COMT rs2075507 and rs737865 polymorphisms were in complete linkage disequilibrium in Han population of Yunnan Province. This study indicates that polymorphisms of ADH1B, ALDH2, CYP4502E1, COMT and 5-HTT were significantly associated with AD in Han majority. The ADH1B *2, ALDH2 *2 alleles, 5-HTTLPR L/L genotype and C/C genotype of the COMT rs737865 polymorphism had an important role in reducing the risk of AD while the c2 allele of CYP4502E1 increased the risk of AD. Therefore, the A-C-A-A haplotype may be a dangerous factor leading to AD.Key words: Yunnan Han population, polymorphism, alcohol dependence, genetic risk factor

Enhancement of Transition Temperature in FexSe0.5Te0.5 Film via Iron Vacancies

The effects of iron deficiency in FexSe0.5Te0.5 thin films (0.8<x<1) on superconductivity and electronic properties have been studied. A significant enhancement of the superconducting transition temperature (TC) up to 21K was observed in the most Fe deficient film (x=0.8). Based on the observed and simulated structural variation results, there is a high possibility that Fe vacancies can be formed in the FexSe0.5Te0.5 films. The enhancement of TC shows a strong relationship with the lattice strain effect induced by Fe vacancies. Importantly, the presence of Fe vacancies alters the charge carrier population by introducing electron charge carriers, with the Fe deficient film showing more metallic behavior than the defect-free film. Our study provides a means to enhance the superconductivity and tune the charge carriers via Fe vacancy, with no reliance on chemical doping.Comment: 15 pages, 4 figure