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An indole compound, tert-butyl 6-chloro-3-(4,4,5,5-tetramethyl-1,3,2- dioxaborolan-2-yl)-1H-indole-1-carboxylate, was synthesized by a simple and efficient three-step substitution reaction. The structure of compounds can not be determined without the most common methods, namely, 1H NMR, 13C NMR, IR, MS. The structure of the target compound was determined by the above methods. Besides, the single crystal was obtained by solvent evaporation method, and the crystal structure data were obtained by means of X-ray diffraction and compared with the molecular crystal structure determined by density functional theory (DFT). Frontier molecular orbitals and molecular electrostatic potential energy are crucial in the study of chemical properties.

An indole compound, tert-butyl 6-chloro-3-(4,4,5,5-tetramethyl-1,3,2- dioxaborolan-2-yl)-1H-indole-1-carboxylate, was synthesized by a simple and efficient three-step substitution reaction. The structure of compounds can not be determined without the most common methods, namely, 1H NMR, 13C NMR, IR, MS. The structure of the target compound was determined by the above methods. Besides, the single crystal was obtained by solvent evaporation method, and the crystal structure data were obtained by means of X-ray diffraction and compared with the molecular crystal structure determined by density functional theory (DFT). Frontier molecular orbitals and molecular electrostatic potential energy are crucial in the study of chemical properties.

ObjectivesTo investigate the potential value of a contrast enhanced computed tomography (CECT)-based radiological-radiomics nomogram combining a lymph node (LN) radiomics signature and LNs’ radiological features for preoperative detection of LN metastasis in patients with pancreatic ductal adenocarcinoma (PDAC).Materials and methodsIn this retrospective study, 196 LNs in 61 PDAC patients were enrolled and divided into the training (137 LNs) and validation (59 LNs) cohorts. Radiomic features were extracted from portal venous phase images of LNs. The least absolute shrinkage and selection operator (LASSO) regression algorithm with 10-fold cross-validation was used to select optimal features to determine the radiomics score (Rad-score). The radiological-radiomics nomogram was developed by using significant predictors of LN metastasis by multivariate logistic regression (LR) analysis in the training cohort and validated in the validation cohort independently. Its diagnostic performance was assessed by receiver operating characteristic curve (ROC), decision curve (DCA) and calibration curve analyses.ResultsThe radiological model, including LN size, and margin and enhancement pattern (three significant predictors), exhibited areas under the curves (AUCs) of 0.831 and 0.756 in the training and validation cohorts, respectively. Nine radiomic features were used to construct a radiomics model, which showed AUCs of 0.879 and 0.804 in the training and validation cohorts, respectively. The radiological-radiomics nomogram, which incorporated the LN Rad-score and the three LNs’ radiological features, performed better than the Rad-score and radiological models individually, with AUCs of 0.937 and 0.851 in the training and validation cohorts, respectively. Calibration curve analysis and DCA revealed that the radiological-radiomics nomogram showed satisfactory consistency and the highest net benefit for preoperative diagnosis of LN metastasis.ConclusionsThe CT-based LN radiological-radiomics nomogram may serve as a valid and convenient computer-aided tool for personalized risk assessment of LN metastasis and help clinicians make appropriate clinical decisions for PADC patients.

Compared with angiotensin-converting enzyme inhibitors and angiotensin receptor blockers, Sacubitril/Valsartan has been reported to have superior results. However, the effects of sacubitril/valsartan on heart failure with preserved ejection fraction (HFpEF) are still in dispute.This study aims to evaluate the effects of sacubitril/valsartan on the treatment of HFpEF patients.PubMed, Embase, Web of Science, Cochrane Library, and Clinicaltrials.gov were used to search for randomised controlled trials of sacubitril/valsartan in HFpEF patients from inception to 7 December 2020.Four studies, with a total of 7739 participants, met the inclusion criteria. The present meta-analysis results showed that compared with the control group, sacubitril/valsartan reduced the hospitalisation rate of HF in HFpEF patients [Risk Ratio(RR): 0.85; 95% confidence interval (CI): 0.79-0.93;Our study shows that compared with valsartan or individualised medical therapy (IMT), there were not different between the two groups except for the hospitalisation rate which was favoured by Sacubitril/Valsartan treatment group for HFpEF patients.

The increasing use of the Internet with vehicles has made travel more convenient. However, hackers can attack intelligent vehicles through various technical loopholes, resulting in a range of security issues. Due to these security issues, the safety protection technology of the in-vehicle system has become a focus of research. Using the advanced autoencoder network and recurrent neural network in deep learning, we investigated the intrusion detection system based on the in-vehicle system. We combined two algorithms to realize the efficient learning of the vehicle’s boundary behavior and the detection of intrusive behavior. In order to verify the accuracy and efficiency of the proposed model, it was evaluated using real vehicle data. The experimental results show that the combination of the two technologies can effectively and accurately identify abnormal boundary behavior. The parameters of the model are self-iteratively updated using the time-based back propagation algorithm. We verified that the model proposed in this study can reach a nearly 96% accurate detection rate.

As visible light photocatalysts, narrow bandgap semiconductors can effectively convert solar energy to chemical energy, exhibiting potential applications in alleviating energy shortage and environmental pollution. Cu2O hollow spheres with a narrow band gap and uniform hierarchical structures have been fabricated in a controlled way. The one-pot solvothermal method without any template is simple and facile. The morphologies, crystal structures, composition, specific surface areas, and optical and photoelectric properties of the products were analyzed by various techniques. The hollow and solid Cu2O spheres could be fabricated by controlling the reaction time, and a possible growth process of the Cu2O hollow spheres was revealed. The degradation of methyl orange (MO) was used to investigate the visible-light catalytic properties of the Cu2O samples. More than 90% of MO is degraded under visible light illumination of 20 min, exhibiting a quick catalytic reaction. The rate constant of the Cu2O hollow spheres was 2.54 times and 46.6 times larger than those of the Cu2O solid spheres and commercial Cu2O powder, respectively. The possible photocatalytic mechanism of MO was revealed over Cu2O hollow spheres through the detection of active species. The as-prepared Cu2O hollow spheres display improved visible-light catalytic activity and stability, indicating their potential application in wastewater treatment.

Two‐dimensional material (2D) that possesses atomic thin geometry and remarkable properties is a star material for the fundamental researches and advanced applications. Defects in 2D materials are critical and fundamental to understand the chemical, physical, and optical properties. Photoluminescence arises in 2D materials owing to various physical phenomena including activator/dopant‐induced luminescence and defect‐related emissions, and so forth. With the advanced transmission electron microscopy (TEM) technologies, such as aberration correction and low voltage technologies, the morphology, chemical compositions and electronic structures of defects in 2D material could be directly characterized at the atomic scale. In this review, we introduce the applications of state‐of‐the‐art TEM technologies on the studies of the role of atomic defects in the photoluminescence characteristics in 2D material. The challenges in spatial and time resolution are also discussed. It is proved that TEM is a powerful tool to pinpoint the relationship between the defects and the photoluminescence characteristics.

We study the effect of the strain on the band structure and the valley-dependent transport property of graphene heterojunctions. It is found that valley-dependent separation of electrons can be achieved by utilizing the strain and on-site energies. In the presence of the strain, the values of the transmission can be effectively adjusted by changing the strengths of the strain, while the transport angle basically keeps unchanged. When an extra on-site energy is simultaneously applied to the central scattering region, not only are the electrons of valleys K and K' separated into two distinct transmission lobes in opposite transverse directions, but the transport angles of two valleys can be significantly changed. Therefore, one can realize an effective modulation of valley-dependent transport by changing the strength and stretch angle of the strain and on-site energies, which can be exploited for graphene-based valleytronics devices., 7 pages, 10 figures

Flexible chemical sensor with high sensitivity and reliability is important for health monitoring applications. A typical sodium-ion detection sensor based on ion selection is made of a reference electrode and a working electrode. The reliability of the electrodes is still challenging to achieve accurate and continuous measurements. Here we use the polydopamine-printed technology and chemical annealing method to prepare the flexible sodium-ion detection sensor that presents enhanced reliability. A sensitivity of 54 mV per decade is achieved for the sensor. In the best case, the reliabilities of the working and the reference electrodes are increased up to 95.3% and 93.9%, respectively for the detection of the sodium-ion concentration. This work provides a method to improve the stability of the flexible ion detection sensors.

Nonproductive adsorption of cellulase on lignin was a major inhibitory mechanism reducing the enzymatic saccharification efficiency of lignocellulosic material. The surface and structural properties of Fenton reaction-oxidized lignins (FRLs) and their effects on the nonproductive binding of enzymes to lignin and enzymatic saccharification of Avicel were examined. The Fenton chemistry pretreatment not only decreased the ratio of syringyl to guaiacyl units and the phenolic OH group content in lignin preparations but increased the carboxylic content and the negative zeta potential of lignin, all of which could be responsible for reducing the unproductive adsorption of cellulase on lignin. And Langmuir adsorption isotherms also proved that FRLs were provided with a lower binding ability to the cellulase enzyme when compared with untreated milled bamboo lignin (MBL). Finally, when the nonproductive binding of cellulase to FRLs was reduced significantly, the 72 h glucose yields of Avicel with 3-FRL and 5-FRL we...

Printed electronic technologies draw tremendous attention worldwide due to their ability to surpass the limitations of traditional high-cost electronics based on rigid silicon and manufacture various devices on flexible substrates. As a critical component of flexible electronics, electrodes fabricated on soft, bendable and stretchable substrates are of great importance. Based on the fabrication process, this paper classifies the mainstream technologies into two categories: top-down and bottom-up. To be specific, the top-down technology includes physical evaporation methods, printing technologies and soft lithography and the bottom-up technology involves polymer-assisted-metal-deposition methods and ion-exchange methods, respectively. In contrast to the top-down technology that transfers the functional ink onto the substrate directly, the bottom-up methods achieve great improvement in the adhesion between the substrates and the metal electrodes. In the end of the paper, the challenges for top-down technologies, including costs, synthesis and choice of ink for printing technologies, the limited choice of metal for bottom-up technologies and the mass production of these methods are also discussed.

Objective This study aimed to investigate the incidence and related risk factors of cerebral microbleeds (CMBs) in young and middle-aged patients with hypertension. Methods The study included 232 young and middle-aged (18-59 years-old) patients with hypertension from September 2014 to December 2016 in the Department of Neurology, Affiliated Hospital of Guizhou Medical University, China. The data were recorded which included demographics, vascular risk factors, medication history, and imaging data of patients. CMBs were evaluated based on the microbleeds anatomical rating scale. Results Of the enrolled participants, 115 were CMB positive, accounting for 49.6%. CMBs were more prone to occur in deep regions than in others (39.13%). Multiple cerebral microbleeds were associated with white matter hyperintensities(WMH), dyslipidemia, hyperhomocysteine, and uric acid. Moreover, WMH, dyslipidemia, ever smoker, antiplatelets use, and hyperhomocysteine were found to be risk factors for deep or infratentorial CMBs in young and middle-aged patients with hypertension. However, the lobar CMBs only had an independent correlation with dyslipidemia in these participants. Conclusions The incidence of CMBs in patients with hypertension was relatively high. It mostly occurred in a deep or infratentorial area with more vascular-associated risk factors. However, in patients with lobar CMBs, factors associated with lipid metabolism, such as amyloid deposition and unidentified genotype variation, may be crucial. Screening and regular follow-ups of CMBs by Susceptibility Weighted Imaging and active prevention in young and middle-aged patients with hypertension have clinical significance for timely understanding and predicting the occurrence and development of related cerebrovascular disease events.

Through the analysis of TN-C and TN-S connection mode, this paper expounds the advantages and disadvantages of TN, the voltage distribution of the load is introduced through an example, and further introduces the necessity of developing neutral wire over current alarm device in the distribution network, and it discusses the composition, working principle and using method of the neutral wire over current alarm device. Through the application in the field, it is proved that the use this device for distribution network can prevent the neutral line outage and have the advantages of early warning. The development can improve corporate image, and has a wide range of promotion value and application prospects.

A new organic-inorganic hybrid coordination compound ZnQS (en)?2H2O (1) in which two different organic ligands, ethylenediamine (en) and 8-hydroxy-quinoline-5-sulfonic acid (H2QS) coordinate with zinc ions, has been synthesized via the evaporation method and characterized by single crystal X-ray diffraction analysis, IR spectroscopy and thermogravimetric analysis (TGA). The structure solution showed that compound 1 displays a three-dimensional supramolecular network by synergic linkage of hydrogen and coordinated bonds. Moreover, compound 1 exhibits intense photoluminescence at 513 nm excited at 396 nm in the solid state at room temperature.

How to obtain accurate channel state information (CSI) at the transmitter with less pilot overhead for frequency division duplexing (FDD) massive multiple-input multiple-output (MIMO) system is a challenging issue due to the large number of antennas. To reduce the overwhelming pilot overhead, a hybrid orthogonal and non-orthogonal pilot distribution at the base station (BS), which is a generalization of the existing pilot distribution scheme, is proposed by exploiting the common sparsity of channel due to the compact antenna arrangement. Then the block sparsity for antennas with hybrid pilot distribution is derived respectively and can be used to obtain channel impulse response. By employing the theoretical analysis of block sparse recovery, the total coherence criterion is proposed to optimize the sensing matrix composed by orthogonal pilots. Due to the huge complexity of optimal pilot acquisition, a genetic algorithm based pilot allocation (GAPA) algorithm is proposed to acquire optimal pilot distribution locations with fast convergence. Furthermore, the Cramer Rao lower bound is derived for non-orthogonal pilot-based channel estimation and can be asymptotically approached by the prior support set, especially when the optimized pilot is employed.

Graphene is a typical two-dimensional material which has fascinating electrical, mechanical, and optical properties. In particular, graphene-based smart MEMS/NEMS devices can automatically respond to external electric stimulation and convert to mechanical movement. Actuator is one of the most potential applications of graphene-based MEMS. However, its reliability investigation has rarely been reported. Here we report the failure mechanism of a bimorph actuator fabricated by reduced graphene (RGO) and graphene oxide (GO). Our findings pave a way to the fundamental understanding of reliability issues on graphene-based actuators.

In this paper, a grid-base autonomous geographic routing is proposed to decrease end-to-end delay and improve network capability for wireless sensor networks. After numbering grids in sequence, every grid has a unique ID. In this case, any node can utilize local decision to figure out which neighboring grid is closest to the center nodes. Since it is not needed to establish a routing in advance, this algorithm is very suitable for dynamic networks, real-time traffics and burst communications. By Matlab and Ns-2 simulation, the novel routing algorithm exhibits excellent performance in packet delivery fraction, end-to-end delay, protocol overhead, and path length.

In the radio channel, compression is used for transmission of real-time analog video signal and compressed bits can usually be transmitted at a non-constant rate. But standard video can be displayed on TV at a constant rate. It is difficult to decode the intermittent compressed data for real-time video display. In order to solve the problem which rate of video decoding and compressed bits in the radio channel does not match, a method is brought forward. By controlling the data which transmit to the decoder, the real-time sequential video can be displayed. And the method has been used to the system of video transmission. Its reliability and validity can be proved.

To sovle high torque ripple at low speed, high frequence noise and slow response caused by torque ripple for conventional control systems of permanent magnet synchronous motor(PMSM), the scheme of Digonal Recurrent Neural Network(DRNN) Dynamic speed Controller for space vector PWM(SVPWM) control of a permanent magnet synchronous motor(PMSM) is presented. The structure of dynamic PID speed Controller based on digonal recurrent neural network(DRNN-PID), and an dynamic learning algorithm are analyzed. The results of simulation are provided to demonstrate system superior characteristics with low torque ripple, few harmonics and the effectiveness of the proposed DRNN dynamic speed Controller under the occurrence of parameter variations and external disturbance.

As one important technoly in converter steelmaking, oxygen lance position control is investigated with self-adaptive fuzzy PID strategy. We employ the fuzzy reasoning to realize the real-time adjustment of the parameter of PID in order to control the oxygen lance position. With the details of the fuzzy controller, the practical oxygen lance is simulated by using Matlab. The results imply that the self-adaptive fuzzy PID has better properties in obtaining dynamical index and steady state than the regular PID control strategy.