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Total synthesis of (±)-applanatumol B has been achieved in in 8 steps from known compound 8 in 5.0% overall yield. The key step features an acid induced cyclization to construct 5/5/6 ...tricyclic skeleton. Incorporation of dimethyl malonate into the pentane ring simplifies the synthesis by reducing stereocenters to two.
Axial ultrasonic vibration–assisted cutting has been proposed and proved preponderance on cutting performance; however, the transient separation cutting characteristic has not been clearly revealed. ...This paper focuses on the transient separation cutting characteristic of axial ultrasonic vibration–assisted cutting and its influence on the cutting performance. First, the separation cutting criteria, including feed coefficient and phase shift, are established and influence factors, such as feed rate, amplitude, and phase shift, are systematically analyzed. Subsequently, the duty ratio is deduced and calculated, and some features and a control mechanism are introduced. In addition, a transient separation cutting model with four stages is demonstrated. The reason for the average cutting force reduction by the transient separation cutting characteristic is also stated. Finally, the verification of the separation cutting and transient separation cutting model and the comparison of the feed thrust force and parameter influences on the cutting performance are experimentally performed. The transient signals of different duty ratios 0.55 to 1 are obtained, and 10 to 40% reductions of feed thrust are measured both by a PCB sensor and a Kistler dynamometer. The influence degree of the feed coefficient, spindle rotation speed, and cutting depth on the performance is analyzed. A parameter combination of smaller feed coefficient, moderate spindle rotation speed, and smaller cutting depth is suggested to obtain a better cutting performance by fully considering the cutting force, surface roughness, and tool life.
Anomaly detection is a highly important task in the field of data analysis. Traditional anomaly detection approaches often strongly depend on data size, structure and features, while introducing the ...idea of ensemble into anomaly detection can greatly improve the generalization ability. Ensemble-based anomaly detection methods still face some challenges, however, such as data imbalance, time and space demand and the selection of base detectors. To this end, we propose a selective ensemble method for anomaly detection based on parallel learning (SEAD-PL). First, a differentiated stratified sampling method is designed to alleviate the problem of data imbalance. Then, a distributed parallel training frame is built to address the problem of excessive time and space consumption for base detector training. Finally, a clustering-based ensemble selection strategy is introduced to balance the accuracy and diversity of base detectors. Experiments are performed on six datasets, which demonstrate that the proposed method has obvious advantages over four selected methods.
Cybersecurity risk assessment is an important means of effective response to network attacks on industrial control systems. However, cybersecurity risk assessment process is susceptible to subjective ...and objective effects. To solve this problem, this paper introduced cybersecurity risk assessment method based on fuzzy theory of Attack-Defense Tree model and probability cybersecurity risk assessment technology, and applied it to airport automatic fuel supply control system. Firstly, an Attack-Defense Tree model was established based on the potential cybersecurity threat of the system and deployed security equipment. Secondly, the interval probability of the attack path was calculated using the triangular fuzzy quantification of the interval probabilities of the attack leaf nodes and defensive leaf nodes. Next, the interval probability of the final path was defuzzified. Finally, the occurrence probability of each final attack path was obtained and a reference for the deployment of security equipment was provided. The main contributions of this paper are as follows: (1) considering the distribution of equipment in industrial control system, a new cybersecurity risk evaluation model of industrial control system is proposed. (2) The experimental results of this article are compared with other assessment technologies, and the trend is similar to that of other evaluation methods, which proves that the method was introduced in this paper is scientific. However, this method reduces the subjective impact of experts on cybersecurity risk assessment, and the assessment results are more objective and reasonable. (3) Applying this model to the airport oil supply automatic control system can comprehensively evaluate risk, solve the practical problems faced by the airport, and also provide an important basis for the cybersecurity protection scheme of the energy industry.
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•Multitude advances were found for V-rich Bi2S3 nanowire than pristine Bi2S3 photoelectrode.•V-rich Bi2S3 nanowires achieve excellent photocurrent density for water splitting under ...visible light.•Deep insights on how the V-rich feature affects the PEC performance of Bi2S3.
Bi2S3 is a n-type (negative type) semiconductor that has a narrow band gap and an ideal band edge position for hydrogen generation. However, high charge recombination rate, low photoelectrochemical (PEC) efficiency and poor stability are of major concerns of Bi2S3 as a photoelectrode. Herein, we report an efficient Vanadium-rich Bi2S3 nanowires (atomic ratio of V to Bi is 1/22) that have been prepared on fluorine-doped tin oxide (FTO) substrate by an in-situ solution-processed reaction with BiVO4 film as precursor. The resulting V-rich photoelectrode demonstrates notably high charge separation efficiency and fast charge transport with respect to pristine Bi2S3 nanowires. As a result, the photocurrent density of ca. 10 mA·cm−2 at -0.2 V vs Ag/AgCl is obtained under visible light illumination. In addition, V-rich Bi2S3 generates IPCE (incident photocurrent-to-current conversion efficiency) of 50% at 460 nm and 45% at 760 nm, demonstrating a 2.0 and 2.8-fold increase, respectively, when compared with pristine Bi2S3. This enhancement is probably due to increased light absorption, less charge recombination, and faster charge transfer. More importantly, in contrast to pristine Bi2S3 sample that suffers detrimental photocorrosion in sulfide containing electrolyte, V-rich Bi2S3 nanowires retain 84.6% of its initial photocurrent over the course of 1 h. These findings are expected to shed light on engineering high-performance and robust metal sulfide materials for photoelectrochemical application.
In order to have more accurate control over the compression molding of automobile coat rack, improve the quality of molding products, and achieve the goal of lightweight design, a novel mechanical ...model for the main two-layer composite structure of the coat rack is proposed. In this regard, the main factors affecting the mechanical properties of the composite structure are obtained. The hot air convection is selected for the sheet preheating. During the experiment, the hot air temperature, preheating time, molding pressure, and pressing holding time are set to 250°C, 110 s, 13 MPa, and 80 s, respectively. Moreover, the error compensation method is applied to compensate for the shrinkage of the product during solidification and cooling. The LS-DYNA finite element software is used to simulate the molding process of the main body of the coat rack, and the node force information with large deformation is obtained accordingly. The load mapping is used as the boundary condition of mold topology optimization, and the compression molding of the main body of the coat rack is optimized. A lightweight design process and method for the compression molding of automotive interior parts and a mathematical model for the optimization of the solid isotropic material penalty (SIMP) (power law) material interpolation of the concave and convex molds are established. Based on the variable density method, OptiStruct is used for the lightweight design of the convex and concave molds of the main body of the coat rack, which reduces the mold weight by 15.6% and meets the requirements of production quality and lightweight.
For shortcomings of current smart home system and power line carrier insufficient data transferring, an intelligent sensor networks system based on intelligent gateway is studied in this paper. Smart ...home system includes internal network, intelligent gateway, and external network. Multiple servers are designed in gateway, which start at the same time and receive various forms of data. Then data is processed for internal network format. External network includes several modes of communication such as TCP/IP, UDP, and pipe. Internal network includes ZigBee wireless and power line carrier (PLC) communication. Power line carrier protocol is improved, and it expands data transmission capacity to accommodate communication needs of modern family. Smart home system is designed as modules, such as intelligent gateway module, power line carrier communication module, ZigBee wireless communication modules, and appliance within electric equipment. Finally this system is physically designed and verified. The smart home system introduced in this paper has easily used and has strong compatibility.
To develop a deep learning-based model using esophageal thickness to detect esophageal cancer from unenhanced chest CT images.
We retrospectively identified 141 patients with esophageal cancer and ...273 patients negative for esophageal cancer (at the time of imaging) for model training. Unenhanced chest CT images were collected and used to build a convolutional neural network (CNN) model for diagnosing esophageal cancer. The CNN is a VB-Net segmentation network that segments the esophagus and automatically quantifies the thickness of the esophageal wall and detect positions of esophageal lesions. To validate this model, 52 false negatives and 48 normal cases were collected further as the second dataset. The average performance of three radiologists and that of the same radiologists aided by the model were compared.
The sensitivity and specificity of the esophageal cancer detection model were 88.8% and 90.9%, respectively, for the validation dataset set. Of the 52 missed esophageal cancer cases and the 48 normal cases, the sensitivity, specificity, and accuracy of the deep learning esophageal cancer detection model were 69%, 61%, and 65%, respectively. The independent results of the radiologists had a sensitivity of 25%, 31%, and 27%; specificity of 78%, 75%, and 75%; and accuracy of 53%, 54%, and 53%. With the aid of the model, the results of the radiologists were improved to a sensitivity of 77%, 81%, and 75%; specificity of 75%, 74%, and 74%; and accuracy of 76%, 77%, and 75%, respectively.
Deep learning-based model can effectively detect esophageal cancer in unenhanced chest CT scans to improve the incidental detection of esophageal cancer.
Objective
Baicalin, a flavonoid compound purified from the dry roots of
Scutellaria baicalensis
Georgi, has generally been used for the treatment of various allergic diseases. However, there is ...little information about the anti-inflammatory effects of baicalin for allergic rhinitis. This study aims to investigate the anti-allergic effect of baicalin on allergic response in ovalbumin (OVA)-induced allergic rhinitis guinea pigs and lipopolysaccharide (LPS)-stimulated human mast cells.
Methods
Using in vivo models, we evaluated the effect of baicalin on allergic rhinitis symptoms via recording the number of nasal rubs and sneezes. The levels of histamine, OVA-specific immunoglobulin E(IgE), eosinophil cationic protein (ECP) and inflammatory cytokines were measured using enzyme-linked immunosorbent assay (ELISA). The histological changes of nasal mucosa were observed by light microscope after HE staining. In vitro, the release of histamine and β-hexosaminidase of compound 48/80-induced human mast cells were measured by ELISA and PNP-NAG colorimetry, respectively. The productions of inflammatory cytokines of LPS-stimulated human mast cells were determined using ELISA. Western blot was used to test the protein expression of JAK2, p-JAK2, STAT5, p-STAT5, IKKβ, p-IKKβ, IκBα, p-IκBα and NF-κB (p65) of LPS-stimulated human mast cells.
Results
The oral administration of baicalin at doses of 50 and 200 mg/kg improved allergic rhinitis symptoms and the histological changes of nasal mucosa and decreased the serum levels of histamine, ECP, interleukin (IL)-1β, IL-6, IL-8, tumor necrosis factor (TNF)-α and OVA-specific IgE in OVA-induced allergic rhinitis guinea pigs. In vitro, baicalin suppressed the release of histamine and β-hexosaminidase in compound 48/80-induced human mast cells. In addition, baicalin also inhibited the productions of inflammatory cytokines such as IL-1β, IL-6, IL-8 and TNF-α and suppressed the phosphorylation of JAK2, STAT5, IKKβ, IκBα and the nuclear translocation of NF-κB (p65) subunit in LPS-stimulated human mast cells.
Conclusions
These results suggest that baicalin can effectively prevent allergic response in OVA-induced allergic rhinitis guinea pigs and inhibit inflammatory response via blocking JAK2-STAT5 and NF-κB signaling pathways in LPS-stimulated human mast cells. Considered together,the results show that baicalin may be a useful drug in the treatment of allergic rhinitis.
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