Bistable electrical switching and nonvolatile memory effects by doping different amounts of GO in poly(9,9-dioctylfluorene-2,7-diyl)

Poly(9,9-dioctylfluorene-2,7-diyl) (PFO) was synthesized under a Suzuki coupling reaction, and its structure was proved by Fourier transform infrared (FT-IR) spectroscopy, and hydrogen and carbon nuclear magnetic resonance (¹H-NMR and ¹³C-NMR). A nonvolatile organic memristor, based on active layers of PFO and PFO:GO composite, was prepared by spin-coating and the influence of GO concentration on the electrical characteristics of the memristor was investigated. The results showed that the device had two kinds of conductance behavior: electric bistable nonvolatile flash memory behavior and conductor behavior. With an increase in GO concentration, the device has an increased ON/OFF current ratio, increasing from 2.1 × 10¹ to 1.9 × 10³, a lower threshold voltage (V_SET), decreasing from −1.1 V to −0.7 V, and better stability. The current remained stable for 3 hours in both the ON state and OFF state, and the ON and OFF state current of the device did not change substantially after 9000 read cycles.

The device shows different conductive behavior: electric bistable nonvolatile flash memory behavior and conductor behavior.     

T follicular helper cells improve the response of patients with chronic hepatitis B to interferon by promoting HBsAb production

Journal of Gastroenterology - Hepatitis B surface antigen (HBsAg) seroconversion is considered the optimal outcome of the treatment of chronic hepatitis B virus (HBV) infection. In this study, we...     

Development of SSR and SNP markers for identifying opium poppy

Papaver somniferum L. (opium poppy) is the original plant of heroin, which is a major narcotic drug, and this plant has brought great harm to human health. However, the ban on opium poppy cultivation and trafficking is facing great challenges because of abnormal profits. Therefore, rapid and accurate identification is important to address the abovementioned problems. In this study, eleven simple sequence repeats (SSR) markers and two single nucleotide polymorphism (SNP) markers were mined to distinguish opium poppy from other six Papaver species. These molecular markers were further verified through a large number of plant materials of these seven Papaver species. An excellent multiplex polymerase chain reaction (PCR) system that simultaneously amplifies the three of eleven SSR markers was developed, which effectively improves the efficiency and speed of identification. The present research is of great implication for identifying and investigating the illegal cultivation and trafficking of opium poppy.

     

Research of fetal ECG extraction using wavelet analysis and adaptive filtering

Extracting clean fetal electrocardiogram (ECG) signals is very important in fetal monitoring. In this paper, we proposed a new method for fetal ECG extraction based on wavelet analysis, the least mean square (LMS) adaptive filtering algorithm, and the spatially selective noise filtration (SSNF) algorithm. First, abdominal signals and thoracic signals were processed by stationary wavelet transform (SWT), and the wavelet coefficients at each scale were obtained. For each scale, the detail coefficients were processed by the LMS algorithm. The coefficient of the abdominal signal was taken as the original input of the LMS adaptive filtering system, and the coefficient of the thoracic signal as the reference input. Then, correlations of the processed wavelet coefficients were computed. The threshold was set and noise components were removed with the SSNF algorithm. Finally, the processed wavelet coefficients were reconstructed by inverse SWT to obtain fetal ECG. Twenty cases of simulated data and 12 cases of clinical data were used. Experimental results showed that the proposed method outperforms the LMS algorithm: (1) it shows improvement in case of superposition R-peaks of fetal ECG and maternal ECG; (2) noise disturbance is eliminated by incorporating the SSNF algorithm and the extracted waveform is more stable; and (3) the performance is proven quantitatively by SNR calculation. The results indicated that the proposed algorithm can be used for extracting fetal ECG from abdominal signals.     

Control of bursting behavior in neurons by autaptic modulation

Firing properties of biological neurons have long been recognized to be determined by extrinsic synaptic afferents that neurons receive and intrinsic ionic mechanisms that neurons possess, however, previous researches have also demonstrated that firing behavior of single neurons can be modulated by the neurons themselves, realized by the autapses. Thus in this investigation, we argued that how autaptic modulations shape the bursting behavior of biological neurons. We considered the issue from the following two aspects: autaptic-excitation and -inhibition. Our results suggested that for autaptic-excitation, under the condition of relatively weak stimulus, regular bursting was more incline to occur when the autaptic strength was weak, while regular spiking was more likely to appear when the autaptic strength was strong. However, larger stimulus would diminish the portion of bursting, but increase the portion of spiking. For autaptic-inhibition, under relatively weak stimulus, a wide range of regular bursting emerges when the autaptic strength was small, but when stronger stimulus were applied, the range of regular bursting shrinked into a small region. Meanwhile, we observed that synaptic delays have no obvious effects in the case of autaptic-excitation, while a subtle effect of synaptic delays was observed in the case of autaptic-inhibition. These results showed that bursting behavior of neurons could be controlled and modulated by the autaptic mechanisms that biological neurons intrinsically possess, and the final results may further promote the understanding in the generation of various neuronal firing patterns.     

SARS-CoV-2对眼部的影响及其经眼途径传播的可能性

SARS-CoV-2引起的新型冠状病毒肺炎（COVID-19）已对全球构成重大的公共卫生威胁。SARS-CoV-2和SARS-CoV均属于人冠状病毒（HCoVs）β属,两者的基因组相似性高达79.6%,且均通过血管紧张素转换酶2（ACE-2）感染宿主细胞。目前已有研究表明,SARS-CoV-2感染与结膜炎具有一定相关性,SARS-CoV-2是否能经眼感染或传播的问题也备受关注,但目前尚缺乏其通过眼部组织感染的临床确诊病例和实验室证据。本文就SARS-CoV-2的病原学特点、流行病学特征、眼部表现及结膜囊病毒感染率作一综述,并对SARS-CoV-2经眼途径传播的可能性进行探讨。     

Significance of proximal femoral computed tomography scanning in the prediction of femoral prosthesis before total hip arthroplasty

Femoral prosthesis before total hip arthroplasty (THA) predicted by Proximal Femoral CT scanning. Prior to THA, 61 hip bones in 52 cases were scanned by CT to measure the minimum inner diameter of cavum medullare in femur isthmus. The corresponding type of femoral prosthesis was selected according to the size of the cavum medullares. The conventional template measuring method was used as a contrast. The minimum inner diameter of cavum medullare in femur isthmus and the medial diameter of cavum medullare of resected femur had strong correlation with the type of femoral prosthesis (r = 0.97–0.99, P < 0.05). In terms of pre-operative femoral prosthesis selection, the CT-based isthmus-measuring method had an excellence rate of 47.5%. This method had an excellence rate of 52.5%. The CT-based resected-femur-measuring method had better accuracy in pre-operative femoral prosthesis selection for the patients.     

PCPA致大鼠NG2细胞的变化,NG2与GABA的共存关系及酸枣仁汤的干预作用研究

目的:探讨大鼠脑内五羟色胺(5-HT)含量下降后皮质部分NG2细胞的变化,NG2细胞与星形胶质细胞(Ast)、γ-氨基丁酸(GABA)的共存关系及酸枣仁汤的干预作用.方法:根据随机数字表法将雄性SD大鼠分为7d正常组、7d对照组、7d对氯苯丙氨酸(PCPA)组、15 d正常组、15 d对照组、15 d PCPA组、酸枣仁汤(SZRD)组、PCPA+SZRD组,各组大鼠给予相应处理.取大脑皮质前额叶,采取免疫荧光双染法测定大鼠皮质NG2细胞、胶质纤维酸性蛋白(GFAP)、GABA的表达量及NG2/GFAP、NG2/GABA共存定位情况.结果:与7d对照组比较,7 d PCPA组大鼠皮质NG2细胞、GFAP蛋白表达量增加(P＜0.01),GABA蛋白表达量下降(P＜0.05);与15 d PCPA组比较,PCPA+SZRD组大鼠皮质NG2细胞、GFAP蛋白表达量下降(P＜0.01),GABA表达量上升(P＜0.05);NG2细胞与GABA在同一区域表达较多,而与GFAP在同一区域表达较少.结论:5-HT系统的失调能激活皮质NG2细胞、Ast,抑制GABA的表达,NG2细胞可能与Ast、GABA共同影响大脑皮层兴奋性来调节睡眠,酸枣仁汤可能通过5-HT系统调控NG2细胞、Ast、GABA来参与皮层活动的神经调节.     

Thermal Stability and Decomposition Kinetics of 1-Alkyl-2,3-Dimethylimidazolium Nitrate Ionic Liquids: TGA and DFT Study

The thermal stability and decomposition kinetics analysis of 1-alkyl-2,3-dimethylimidazole nitrate ionic liquids with different alkyl chains (ethyl, butyl, hexyl, octyl and decyl) were investigated by using isothermal and nonisothermal thermogravimetric analysis combined with thermoanalytical kinetics calculations (Kissinger, Friedman and Flynn-Wall-Ozawa) and density functional theory (DFT) calculations. Isothermal experiments were performed in a nitrogen atmosphere at 240, 250, 260 and 270 °C. In addition, the nonisothermal experiments were carried out in nitrogen and air atmospheres from 30 to 600 °C with heating rates of 5, 10, 15, 20 and 25 °C/min. The results of two heating modes, three activation energy calculations and density functional theory calculations consistently showed that the thermal stability of 1-alkyl-2,3-dimethylimidazolium nitrate ionic liquids decreases with the increasing length of the alkyl chain of the substituent on the cation, and then the thermal hazard increases. This study could provide some guidance for the safety design and use of imidazolium nitrate ionic liquids for engineering.