Copper-Catalyzed Regiodivergent Asymmetric Difunctionalization of Terminal Alkynes.

We herein describe the first example of ligand-controlled, copper-catalyzed regiodivergent asymmetric difunctionalization of terminal alkynes through a cascade hydroboration and hydroallylation process. The catalytic system, consisting of (R)-DTBM-Segphos and CuBr, could efficiently achieve asymmetric 1,1-difunctionalization of aryl terminal alkynes, while ligand switching to (S,S)-Ph-BPE could result in asymmetric 1,2-difunctionalization exclusively. In addition, alkyl substituted terminal alkynes, especially industrially relevant acetylene and propyne, were also valid feedstocks for asymmetric 1,1-difunctionalization. This protocol is characterized by good functional group tolerance, a broad scope of substrates (> 150 examples), and mild reaction conditions. We also showcase the value of this method in the late-stage functionalization of complicated bioactive molecules and simplifying the synthetic routes toward the key intermediacy of natural product (bruguierol A). Mechanistic studies combined with DFT calculations provide insight into the mechanism and origins of this ligand-controlled regio- and stereoselectivity.

Enantioselective Copper-Catalyzed Sequential Hydrosilylation of Arylmethylenecyclopropanes.

Despite impressive advances in the construction of enantioenriched silacarbocycles featuring silicon-stereogenic centers via a selection of well-defined sila-synthons, the development of a more convenient and economic method with readily available starting materials is significantly less explored and remains a considerable challenge. Herein, we report the first example of copper-catalyzed sequential hydrosilylation of readily accessible methylenecyclopropanes (MCPs) and primary silanes, affording an efficient and convenient route to a wide range of chiral silacyclopentanes bearing consecutive silicon- and carbon-stereogenic centers with excellent enantio- and diastereoselectivities (generally ≥98% ee, > 25:1 dr). Mechanistic studies reveal that these reactions combine copper-catalyzed intermolecular ring-opening hydrosilylation of aryl MCPs and intramolecular asymmetric hydrosilylation of the resultant Z/E mixture of homoallylic silanes.

Design and Experiments of a Real-Time Bale Density Monitoring System Based on Dynamic Weighing.

Bale density is one of the main performance indicators to measure the quality of baler operation. In this study, a real-time baler bale density monitoring system was designed for the problem of difficult real-time measurement of bale density on round balers. Firstly, a weighing calculation model for the rolling and sliding stage of the bale was established, and the dynamic characteristics during the contact between the bale and the inclined surface were analyzed based on ADAMS dynamics simulation. Then, a real-time monitoring system for the bale density based on the contact pressure of the inclined surface, attitude angle measurement and hydraulic monitoring of the cylinder was constructed, and the accuracy of the weighing model was confirmed. The system was used to observe and analyze the changes in the pitch angle of the carrier table and the oil pressure in the rod chamber of the backpack cylinder during the operation of the round baler. Finally, the monitoring system was calibrated and the dynamic calibration equations were obtained. The results show that the maximum error between the calculated value of the original weighing model and the actual weight was 3.63%, the maximum error of the calculated value of the weighing model corrected by the calibration equations was 3.40% and the measurement accuracy could be satisfied. The results show that the system was highly accurate and met the practical needs of bale weighing in the field.

Development and Experiment of an Innovative Row-Controlled Device for Residual Film Collector to Drive Autonomously along the Ridge.

The field harvesting process of harvesting machinery is often affected by high workload and environmental factors that can impede/delay manual rowing, thereby leading to lower efficiency and quality in the residual film collector. To address this challenge, an automatic rowing control system using the 4mz-220d self-propelled residual film collector as the experimental carrier was proposed in this study. Cotton stalks in the ridges were chosen as the research object, and a comprehensive application of key technologies, machinery, and electronic control was used, thereby incorporating a pure tracking model as the path-tracking control method. To achieve the automatic rowing function during the field traveling process, the fuzzy control principle was implemented to adjust the forward distance within the pure tracking model dynamically, and the expected steering angle of the steering wheel was determined based on the kinematic model of the recovery machine. The MATLAB/Simulink software was utilized to simulate and analyze the proposed model, thus achieving significant improvements in the automation level of the residual film collector. The field harvesting tests showed that the average deviation of the manual rowing was 0.144 m, while the average deviation of the automatic rowing was 0.066 m. Moreover, the average lateral deviation of the automatic rowing was reduced by 0.078 m with a probability of deviation within 0.1 m of 95.71%. The research study demonstrated that the designed automatic rowing system exhibited high stability and robustness, thereby meeting the requirements of the autonomous rowing operations of residual film collectors. The results of this study can serve as a reference for future research on autonomous navigation technology in agriculture.

Asymmetric Radical Oxyboration of ß-Substituted Styrenes via Late-Stage Stereomutation.

Herein, we report an unprecedented copper-catalyzed highly enantio- and diastereoselective radical oxyboration of ß-substituted styrenes. The lynchpin of success is ascribed to the development of a late-stage stereomutation strategy, which enables enantioenriched cis-isomers among a couple of early-generated diastereomers to be converted into trans-isomer counterparts, thus fulfilling high diastereocontrol; while the degree of enantio-differentiation is determined by the borocupration process of the C=C bond. This reaction provides an efficient protocol to access enantioenriched trans-1,2- dioxygenation products. The value of this method has further been highlighted in a diversity of follow-up stereospecific transformations and further modifying complex molecules.

Association between eating behaviors and depressive symptoms in Chinese adults: a population-based cross-sectional study.

Eating behaviors are associated with health outcomes. However, data regarding the association between eating behaviors and depressive symptoms in Chinese adults are limited. We hypothesized that Chinese adults with problematic eating behaviors would likely have depressive symptoms compared to those with good eating behaviors. We included 1,998 participants (aged 25-68). Logistic regression models were used to estimate odds ratios and 95% confidence intervals for the association between eating behaviors and depressive symptoms. Eating behaviors were assessed using a self-administered questionnaire. Depressive symptoms were assessed using the Self-Rating Depression Scale. In the final adjusted model, the odds ratios and 95% confidence intervals for depressive symptoms were 1.23 (0.99-1.53) and 1.30 (0.97-1.74) when a slow eating rate was compared to medium and fast eating rates, respectively and were 1.35 (1.08-1.68) and 1.40 (1.07-1.83) when breakfast consumers were compared to occasional consumers and skippers, respectively. Eating quickly and skipping breakfast were associated with an increased risk of depressive symptoms. These results suggest that eating behaviors may affect mental health in adults.

Remote Site-Selective Asymmetric Protoboration of Unactivated Alkenes Enabled by Bimetallic Relay Catalysis.

A remote C(sp3 )-H bond asymmetric borylation of unactivated alkenes was achieved by bimetallic relay catalysis. The reaction proceeded through reversible and consecutive ß-H elimination/olefin insertion promoted by CoH species generated in situ, followed by copper-catalyzed asymmetric protoboration. The use of this synergistic Co/Cu catalysis protocol allowed the enantioselective protoboration of various unactivated terminal alkenes and internal alkenes, as well as an unrefined mixture of olefin isomers, at the distal less-reactive ß-position to a functional group, leading to chiral organoboronates.

P53 suppresses the progression of hepatocellular carcinoma via miR-15a by decreasing OGT expression and EZH2 stabilization.

Existing literature has highlighted the tumour suppressive capacity of microRNA-15a (miR-15a); however, its role in hepatocellular carcinoma (HCC) remains relatively unknown. This study aimed to investigate the role of miR-15a in HCC and the associated underlying mechanism. Initially, RT-qPCR was performed to detect the expression of miR-15a in HCC tissues and cells. Bioinformatics analysis, Pearson correlation coefficient, dual-luciferase reporter assay, and molecular approaches were all conducted to ascertain the interaction between miR-15a and O-linked N-acetylglucosamine (GlcNAc) transferase (OGT). PUGNAc treatment and cycloheximide (CHX) assay were performed to evaluate O-GlcNAc and the stabilization of the enhancer of zeste homolog 2 (EZH2). Finally, gain- and loss-of-function studies were employed to elucidate the role of P53 and the miR-15a/OGT/EZH2 axis in the progression of HCC, followed by in vivo experiments based on tumour-bearing nude mice. Our results demonstrated that the miR-15a expression was decreased in the HCC tissues and cells. P53 upregulated miR-15a expression, which inhibited the proliferation, migration and invasion of HCC cells, while inducing apoptosis and triggering a G0/G1 cell cycle phase arrest. OGT stabilized EZH2 via catalysing O-GlcNAc, which reversed the effect of P53 and miR-15a. The results of our in vivo study provided evidence demonstrating that P53 could suppress the development of HCC via the miR-15a/OGT/EZH2 axis. P53 was found to inhibit the OGT expression by promoting the expression of miR-15a, which destabilized EZH2 and suppressed the development of HCC. The key findings of our study highlight a promising novel therapeutic strategy for the treatment of HCC.

Associations of the neutrophil to lymphocyte ratio with intracranial artery stenosis and ischemic stroke.

BACKGROUND: The neutrophil-to-lymphocyte ratio (NLR) has emerged as an inflammatory marker. However, the associations of NLR with intracranial artery stenosis (ICAS) and ischemic stroke remain unclear. This study aimed to examine the associations of NLR with ICAS and ischemic stroke among a large and high-risk population. METHODS: Participants with records of clinical characteristics were prospectively recruited from the Neurology Department and Health & Physical Examination Center of Qingdao Municipal Hospital. Logistic regression analysis was used to examine the associations of NLR with ICAS and ischemic stroke. Moreover, we also conducted parametric mediation analysis to estimate the effect of NLR on the risk of ischemic stroke mediated through ICAS. RESULTS: A total of 2989 participants were enrolled in this study. After adjusting for covariates, NLR (OR = 1.125, 95%CI 1.070-1.183) and ICAS (OR = 1.638, 95%CI 1.364-1.967) were significantly associated with ischemic stroke. Compared with the first quartile NLR, the second, third and fourth quartiles NLR were independent risk predictors for ischemic stroke (P for trend < 0.001); the third and fourth quartiles were independent predictors for ICAS (P for trend < 0.001). The mediation analysis showed that ICAS partially mediated the association between NLR and ischemic stroke, accounting for 14.4% of the total effect (P < 0.001). CONCLUSIONS: NLR was significantly associated with ICAS and ischemic stroke. Besides, ICAS partially mediated the association between NLR and ischemic stroke.

Identification of a New Uncompetitive Inhibitor of Adenosine Deaminase from Endophyte Aspergillus niger sp.

Adenosine deaminase (ADA) is an enzyme widely distributed from bacteria to humans. ADA is known as a potential therapeutic target for the treatment of lymphoproliferative disorders and cancer. Endophytes are endosymbionts, often bacteria or fungi, which live within plant tissues and internal organs or intercellular space. Endophytes have a broad variety of bioactive metabolites that are used for the identification of novel natural compounds. Here, 54 morphologically distinct endophyte strains were isolated from six plants such as Peganum harmala Linn., Rheum officinale Baill., Gentiana macrophylla Pall., Radix stephaniae tetrandrae, Myrrha, and Equisetum hyemale Linn. The isolated strains were used for the search of ADA inhibitors that resulted in the identification of the strain with the highest inhibition activity, Aspergillus niger sp. Four compounds were isolated from this strain using three-step chromatography procedure, and compound 2 was determined as the compound with the highest inhibition activity of ADA. Based on the results of 1H and 13C NMR spectroscopies, compound 2 was identified as 3-(4-nitrophenyl)-5-phenyl isoxazole. We showed that compound 2 was a new uncompetitive inhibitor of ADA with high cytotoxic effect on HepG2 and SMCC-7721 cells (the IC50 values were 0.347 and 0.380 mM, respectively). These results suggest that endophyte strains serve as promising sources for the identification of ADA inhibitors, and compound 2 could be an effective drug in the cancer treatment.

Active plasmonic band-stop filters based on graphene metamaterial at THz wavelengths.

Active plasmonic band-stop filters based on single- and double-layer doped graphene metamaterials at the THz wavelengths are proposed and investigated numerically by using the finite-difference time-domain (FDTD) method. The metamaterial unit cell structure is composed of two parallel graphene nanoscale ribbons. Simulated results exhibit that significant resonance wavelength shifts can be achieved with a slight variation of the doping concentration of the graphene ribbons. Besides, the asymmetry double-layer graphene metamaterial device has two apparent filter dips while the symmetry single-, double-layer and asymmetry single-layer graphene metamaterial devices just only one. The metamaterials with symmetry single-layer and asymmetry double-layer graphene can be used as a high-sensitivity refractive sensor with the sensitivity up to 5100 nm/RIU and a two-circuit switch, respectively. These prospects pave the way towards ultrafast active graphene-based plasmonic devices for THz applications.

Upregulation of (C-X-C motif) Ligand 13 (CXCL13) Attenuates Morphine Analgesia in Rats with Cancer-Induced Bone Pain.

BACKGROUND The aim of this study was to investigate the role of chemokine (C-X-C motif) ligand 13 (CXCL13) in morphine tolerance in rats with cancer-induced bone pain (CIBP). MATERIAL AND METHODS We established a rat CIBP model and a rat CIBP-morphine tolerance (BM) model. BM rats were intrathecally administered rmCXCL13, neutralizing anti-CXCL13, and normal saline, while the control group rats underwent a sham operation and were injected with normal saline. The morphine analgesia was assessed by measuring mechanical withdrawal threshold (MWT) and mechanical withdrawal duration (MWD) at various time points. The co-expressions of CXCL13 and NeuN were measured by immunofluorescence double-staining. CXCL13 protein and mRNA expressions were detected by Western blot and quantitative real-time polymerase chain reaction (RT-qPCR), respectively. RESULTS Compared to the sham-operation (S) group, the BM group showed obviously decreased MWT and increased MWD on Day 9 after CIBP, but obviously increased MWT and decreased MWD on Day 3 after morphine administration; subsequently, the MWT was decreased and MWD was increased (all P<0.05). In comparison with the S+saline group, increased MWT and decreased MWD were observed in BM rats on Day 3 after anti-CXCL13 administration, and obviously decreased MWT and increased MWD were found in BM rats on Day 3 after rmCXCL13 administration (all P<0.05). CONCLUSIONS Up-regulated CXCL13 has a negative role in morphine analgesia in relief of CIBP, which may provide a new target for the management of CIBP.

[The Near Infrared Spectral Bands Optimal Selection in the Application of Liquor Fermented Grains Composition Analysis].

In order to improve the technical level of the rapid detection of liquor fermented grains, in this paper, use near infrared spectroscopy technology to quantitative analysis moisture, starch, acidity and alcohol of liquor fermented grains. Using CARS, iPLS and no information variable elimination method (UVE), realize the characteristics of spectral band selection. And use the multiple scattering correction (MSC), derivative and standard normal variable transformation (SNV) pretreatment method to optimize the models. Establish models of quantitative analysis of fermented grains by PLS, and in order to select the best modeling method, using R2, RMSEP and optimal number of main factors to evaluate models. The results showed that the band selection is vital to optimize the model and CARS is the best optimization of the most significant effect. The calculation results showed that R2 of moisture, starch, acidity and alcohol were 0.885, 0.915, 0.951, 0.885 respectively and RMSEP of moisture, starch, acidity and alcohol were 0.630, 0.519, 0.228, 0.234 respectively. After optimization, the model prediction effect is good, the models can satisfy the requirement of the rapid detection of liquor fermented grains, which has certain reference value in the practical.

Efficacy of multi-slice spiral computed tomography in evaluating gastric cancer recurrence after endoscopic submucosal dissection.

BACKGROUND: Recurrence is the major challenge facing endoscopic submucosal dissection (ESD)-based treatment therapies for early gastric cancer (EGC). Urgent development of simple and easy surveillance approaches will enhance clinical treatment of the disease. AIM: To explore the role of computed tomography (CT) recurrence in evaluating EGC after ESD treatment. METHODS: We retrospectively recruited patients from our endoscopy department, between January 2002 and December 2015, and analyzed their basic characteristics, including symptoms, CT results, and results of endoscopy with biopsy, among others. RESULTS: Among a total of 2150 patients EGC patients surveyed, 1362 met our inclusion and exclusion criteria and were therefore enrolled in our study. The cohort's sensitivity of CT for recurrent GC and specificity were 44.22% and 43.86%, respectively, with negative and positive predictive values of 40.15% (275/685) and 48.01% (325/677), respectively. The area under the curve of arterial and venous CT values for recurrent EGC were 0.545, and 0.604, respectively. Receiver operating characteristic curve revealed no statistically significant differences between arterial and venous CT values for recurrent EGC. CONCLUSION: Enhanced CT has superior diagnostic efficacy, but less accuracy, compared to gold standard techniques in patients with recurrent EGC.

Copper-Catalyzed Defluorinative Boroarylation of Alkenes with Polyfluoroarenes.

A catalytic defluorinative boroarylation of alkenes with polyfluoroarenes and B2pin2 with the assistance of a PCy3-ligated copper catalyst was developed. Taking advantage of bench-stable alkenes as latent nucleophiles and avoiding traditional reliance on stoichiometric quantities of organometallics, this method showcased good functional group compatibility and proceeded under very mild reaction conditions. A series of valuable boronate-containing polyfluoroarenes including all-carbon quaternary carboncenter-containing triaryl alkylboronates that are otherwise difficult to access were efficiently prepared.

Association Analyses of Physical Fitness Parameters and Anxiety Symptoms in Chinese College Students.

Poor physical fitness is related to many negative health outcomes, including mental disorders. However, the relationship between physical fitness and anxiety symptoms among college students remains unclear. Therefore, this study investigated whether physical fitness is related to anxiety symptoms in Chinese college students. Cross-sectional data were collected from 6635 men and 4482 women. Physical fitness was measured via a 50-m sprint, a sit-and-reach test, vital capacity, and a standing long jump for both sexes; 1000-m run and pull-up tests for males; and 800-m run and sit-up tests for females. The seven-item Generalized Anxiety Disorder Scale (GAD-7) was used to evaluate anxiety symptoms. Multivariate linear regression showed that better physical fitness was related to lower GAD-7 scores. In addition, multivariate logistic regression analysis showed that better ability in the 50-m sprint, sit-and-reach test, pull-up test, and vital capacity was related with a lower risk of anxiety symptoms in males, and better ability in the 800-m run and standing long jump was related with a lower risk of anxiety symptoms in females. In conclusion, physical fitness was inversely associated with anxiety symptoms in male and female college students. This association was also independent of confounding factors.

A Structural Design Method of 3D Electromagnetic Wave-Absorbing Woven Fabrics.

Based on the wave absorption model of 3D woven fabric and the zero-reflection equations, a new structural design method of 3D electromagnetic (EM) wave-absorbing woven fabrics was obtained. The 3D woven fabrics fabricated by the proposed method had the structure of a bidirectional angle interlock. Continuous S-2 glass fibers were used as the matching layer of this 3D woven fabric, and continuous carbon fibers were used as the absorbing layer. The absorbing layer satisfied the equivalent EM parameters under the condition of zero reflection. The results of the simulation and experiment showed that the performance trends of the 3D wave-absorbing fabric obtained by this method were consistent with the theory, which verified the correctness of the structure design method. The 3D fabrics obtained by this method have the advantages of wide absorbing frequencies and good absorbing performance (-20 dB). This structural design method also has theoretical guiding significance for the development of 3D wave-absorbing fabrics.

A Review of Electromagnetic Shielding Fabric, Wave-Absorbing Fabric and Wave-Transparent Fabric.

As the basic materials with specific properties, fabrics have been widely applied in electromagnetic (EM) wave protection and control due to their characteristics of low density, excellent mechanical properties as well as designability. According to the different mechanisms and application scenarios on EM waves, fabrics can be divided into three types: EM shielding fabric, wave-absorbing fabric and wave-transparent fabric, which have been summarized and prospected from the aspects of mechanisms and research status, and it is believed that the current research on EM wave fabrics are imperfect in theory. Therefore, in order to meet the needs of different EM properties and application conditions, the structure of fabrics will be diversified, and more and more attentions should be paid to the research on structure of fabrics that meets EM properties, which will be conductive to guiding the development and optimization of fabrics. Furthermore, the application of fabrics in EM waves will change from 2D to 3D, from single structure to multiple structures, from large to small, as well as from heavy to light.

Photoinduced self-structured surface pattern on a molecular azo glass film: structure-property relationship and wavelength correlation.

In this study, three series of star-shaped molecular azo glasses were synthesized, and self-structured surface pattern formation on the azo compound films was studied by laser irradiation at different wavelengths. The molecular azo glasses were synthesized from three core precursors (Tr-AN, Tr-35AN, Tr-H35AN), which were prepared by ring-opening reactions between 1,3,5-triglycidyl isocyanurate and corresponding aniline derivatives. The star-shaped azo compounds were obtained through azo-coupling reactions between the core precursors and diazonium salts of 4-chloroaniline, 4-aminobenzonitrile, and 4-nitroaniline, respectively. By using the two-step reaction scheme, three series of azo compounds with different structures were obtained. The core precursors and azo compounds were characterized by using (1)H NMR, FT-IR, UV-vis, mass spectrometry, and thermal analyses. The self-structured surface pattern formation on films of the azo compounds was studied by irradiating the azo compound films with a normal-incident laser beam at different wavelengths (488, 532, and 589 nm). The results show that the photoinduced surface pattern formation behavior is closely related to the structure of the azo compounds, excitation wavelength, and light polarization conditions. The absorption band position of the π-π* transition is mainly determined by the electron-withdrawing groups on the azo chromophores. When the excitation wavelength is between λ(max) and the band tail at the longer wavelength side, the self-structured surface patterns can be more efficiently induced to form on the films. The 3,5-dimethyl substitution on azo chromophores inhibits the surface pattern formation for certain excitation wavelengths. Increasing molecular interaction also shows an effect of restraining the surface pattern formation. The irradiations with linearly and circularly polarized light cause significant differences in the alignment manner of the pillarlike structures and their saturated height.

Effect of the El Niño-Southern Oscillation on hydrogen and oxygen isotope ratios of precipitation in Guilin, SW China.

This study monitored the isotopic compositions of precipitation in Guilin as well as the influence of El Niño-Southern Oscillation (ENSO) on the isotope ratios and water vapour sources from 2015 to 2016. The results indicate that the lower isotope values of precipitation from ocean water vapour source are affected by long transport distance and fractionation during summer and autumn. In contrast, the isotope values of winter and spring precipitation are affected by continental air masses and their evaporation sources yielding higher values. The intercepts of the local meteoric water line in Guilin are larger than those of the global meteoric water line, which is typical for subtropical monsoon climate. During the El Niño event, development of anomalous anticyclonic circulation enhances the northbound transport over the western Pacific and brings abundant water vapour to the southern part of China. During El Niño event prevailing period, precipitations exhibit a lower δ 18O value and low d (deuterium excess) value, indicating that the 2015/2016 ENSO event had a significant effect on the precipitation distribution, precipitation amount, and isotope ratios in regional precipitation.