Search

In this study, a zero-spin cone-roller traction drive (CRTD) is presented for the joints transmission system in rehabilitation robots due to its high transmission performance and characteristics of overload protection. It can achieve safe interactions among humans, rehabilitation robots, and the environment, making it a potential substitute for traditional gear-based transmission systems. The performance of CRTD, especially efficiency, is studied in this paper based on an elastohydrodynamic lubrication (EHL) model with the considerations of the non-Newtonian effect. The results demonstrate that the overall efficiency differs in different stages, reaching a maximum value of 95%. The overload protection activates when there is a sharp drop in efficiency, and the overload threshold can be identified by the efficiency, which may provide guidance for operation and optimization.

Gastric cancer is an epidemic malignancy that is commonly diagnosed at the late stage. Evidence has elucidated that RAD54B exerts a crucial role in the progress of various tumors, but its specific role and mechanism in gastric cancer remain gloomy.

In this article, we develop an efficient Legendre-Galerkin approximation based on a reduced-dimension scheme for the fourth-order equation with singular potential and simply supported plate (SSP) boundary conditions in a circular domain. First, we deduce the equivalent reduced-dimension scheme and essential pole condition associated with the original problem, based on which a class of weighted Sobolev spaces are defined and a weak formulation and its discrete scheme are also established for each reduced one-dimensional problem. Second, the existence and uniqueness of the weak solution and the approximation solutions are given using the Lax-Milgram theorem. Then, we construct a class of projection operators, give their approximation properties, and then prove the error estimates of the approximation solutions. In addition, we construct a set of effective basis functions in approximate space using orthogonal property of Legendre polynomials and derive the equivalent matrix form of the discrete scheme. Finally, a large number of numerical examples are performed, and the numerical results illustrate the validity and high accuracy of our algorithm.

The working environment and lighting conditions of mining intelligent vehicles are complex. When detecting underground personnel, infrared reflection information and detailed texture information can be fused into visible light images by fusing visible and infrared images to improve the target detection effect. Traditional visible and infrared image fusion methods can lead to blurring of image edges and textures as the number of decomposition layers increases, and the fusion time also increases. At present, deep learning based fusion methods for visible and infrared images are difficult to balance the features in visible and infrared images, resulting in blurred detail information in the fused images. In order to solve the above problems, the image fusion algorithm based on multiple attention modules (IFAM) is proposed. Firstly, convolutional neural networks are used to extract image features from visible and infrared images. Secondly, the extracted features are cross fused using spatial attention and channel attention modules. The fusion weights of the output features of the two attention modules are calculated using the gradient information in the features. The output features of the two attention modules are fused based on the weights. Finally, the image features are restored through deconvolution transformation to obtain the final fused image. The fusion results on the RoadScene dataset and TNO dataset indicate that the IFAM fused image contains both background texture information from visible light images and personnel contour feature information from infrared images. The fusion results on the underground dataset indicate that in low lighting environments, infrared images can compensate for the shortcomings of visible light and are not affected by other light sources in the environment. In low lighting conditions, the personnel contour in the fused image is still obvious. The comparative analysis results show that the information entropy (EN), standard deviation (SD), gradient fusion metric (QAB/F), visual information fidelity for fusion (VIFF), and the union structural similarity index measure (SSIMu) of the image after IFAM fusion are 4.901 3, 88.521 4, 0.169 3, 1.413 5, and 0.806 2, respectively. The overall performance is superior to similar algorithms such as LLF-IOI and NDM.

The mortality rate of severe central nervous system infection is high. Early identifying pathogens and giving targeted antibiotics are critical to reduce the mortality rate. Traditional pathogen detection technologies are difficult to meet clinical requirements due to technical limitations. Recently, metagenomic next⁃generation sequencing (mNGS) has received widespread attention in the infectious field due to its efficiency, high throughput and wide coverage of microorganisms. This article reviews the development of mNGS and its application in severe central nervous system infection, so as to provide a more powerful guarantee for accurate diagnosis and treatment of severe central nervous system infection.

This paper briefly outlines the direction of optimization of the civic education environment, proposes a civic education resource sharing model and an incentive model for educational resource sharing using the resource sharing approach, defines the main body of resource sharing, and establishes a model of the incentive system with students as the main body. Analyze the symbolic meaning of the model and propose the assumption of an educational resource incentive. Combine the revenue maximization function, participation constraints, and incentive constraints to form the incentive model. Using the decision tree algorithm of data mining technology for student participation behavior mining, we get the overall participation average score of undergraduate group cooperative learning, which is 3.576, the overall level of involvement is moderately high. The grade level trend of undergraduate group cooperative learning participation is freshman>fourth year>three years>sophomore years. Combined with the simulation results of the incentive model to analyze the role of the incentive model on the behavioral input of student engagement, the standard error of regression of the teaching incentive of the educational environment of the Civics class on student engagement behavior is 0.473, and the overall mean of the teaching incentive perceived by the students is 3.77, which indicates that the incentive strategy implemented in the educational environment of the Civics class is more satisfactory to the students.

Gastric carcinoma is a frequent malignant tumor worldwide. NM23 plays an important role in pathological processes, including in the occurrence and development of tumors. The purpose of this study is to examine the effect of NM23 transfection of human gastric carcinoma cells (BGC-823) on growth and metastases of BGC-823 abdominal cancer xenografts in nude mice. BGC-823 cells were transfected with an adenovirus vector for NM23 (NM23-OE), transfected with an empty vector (NC), or were not transfected (Ctrl). Eighteen female BALB/c-nu mice were randomly divided into three groups (six per group) according to the type of BGC-823 cells administered by intraperitoneal injection. After 2 weeks, necropsies of mice were performed, abdominal circumferences were measured, and abdominal cavities were searched by ultrasound. In order to observe the xenografts in nude mice, there were gross macroscopic observations and microscopic observations. In addition, immunohistochemical analysis and western blot of NM23 were also performed. Green fluorescence in the NM23-OE and NC cells indicated successful transfection. The multiplicity of infection is 80%. A comparison of the three groups of mice indicated the NM23-OE group had positive conditions (abdominal circumferences: 81.83 ± 2.40 mm), but the other groups had negative conditions and enlarged abdomens (NC: 90.83 ± 2.32 mm; Ctrl: 92.67 ± 2.07 mm). Ultrasound observations confirmed large tumors in the NC and Ctrl groups, but did not find in the NM23-OE group. There were no obvious ascites in the NM23-OE group, but the cytological examination of ascites exfoliation in NC and Ctrl groups indicated that there were large and deep-stained gastric carcinoma cells. Tumor expression of NM23 was greater in the NM23-OE group than in the NC and Ctrl groups (both p < 0.05). In conclusion, transfection of BCG-823 cells with NM23 rather than an empty vector (NC) or no vector (Ctrl) led to reduced growth and metastases of abdominal cancer xenografts in nude mice.

Cyclic di-adenosine monophosphate (c-di-AMP) is a bacterial second messenger that can be recognized by infected host cells and activate the immunoinflammatory response. The purpose of this study is to demonstrate the effect of c-di-AMP on the differentiation of human periodontal ligament stem cells (hPDLSCs) and its underlying mechanisms. In the present study, we find that the gingival crevicular fluid (GCF) of patients with chronic periodontitis has a higher expression level of c-di-AMP than that of healthy people. In vitro, c-di-AMP influences the differentiation of hPDLSCs by upregulating Toll-like receptors (TLRs); specifically, it inhibits osteogenic differentiation by activating NF-κB and ERK/MAPK and promotes adipogenic differentiation through the NF-κB and p38/MAPK signaling pathways. Inhibitors of TLRs or activated pathways reduce the changes induced by c-di-AMP. Our results establish the potential correlation among bacterial c-di-AMP, periodontal tissue homeostasis and chronic periodontitis pathogenesis.

Terahertz (THz) metamaterial sensor is a newly-developing interdisciplinary technology, which combines the essential characteristics of THz spectroscopy and metamaterials, to obtain better sensitivity for trace detection of the different target analytes. Toroidal dipole resonances show great sensing potential due to their suppression of the radiative loss channel. Here, we found a high-quality planar toroidal dipole resonance in the breaking Chinese Taichi-like ring and then designed a novel polarization-independent terahertz toroidal sensor by combining four Taichi-like rings into a cycle unit. The sensor shows high-sensitivity sensing characteristics for the ultrathin analyte and refractive index. The optimized sensitivity of pure analytes under 4 μm coating thickness can numerically reach 258 GHz/RIU in the corresponding ∼1.345 THz frequency domain, which is much higher than that of previously reported sensors. We further fabricated experimentally the sensor and demonstrated its fascinating polarization-independent characteristics. Finally, it was successfully applied to the low-concentration detection (ranging from 0.0001 mg/mL to 10 mg/mL) of Aβ protein associated with Alzheimer’s disease. Our high-sensitivity polarization-independent THz toroidal dipole sensor would give access to rich applications in label-free biosensing.

In unmanned driving and security monitoring in the coal mine, detecting pedestrian targets is very important. But under the influence of special working conditions such as dim light, uneven illumination, complex background, and small and dense pedestrian targets, the pedestrian targets in the image have some problems such as few edge details, low signal-to-noise ratio and high similarity with the background. It is difficult to effectively identify the pedestrian targets under multi-scale occlusion. In order to solve the above problems, a pedestrian detection method for underground coal mine based on image fusion and improved CornerNet-Squeeze is proposed. The image collected by the infrared camera and depth camera is fused at the pixel level using the two-scale image fusion (TIF) algorithm. The morphological processing is carried out for the fused imoge to reduce background interference. Based on the CornerNet-Squeeze network, octave convolution (OctConv) is introduced into the hourglass type backbone network to process the high and low frequency information of image features, so as to enhance the image edge features and improve the detection capability of multi-scale pedestrians. The experimental results show the following points. ① The improved CornerNet-Squeeze model can effectively improve the detection precision of underground pedestrian while maintaining the real-time performance of the original algorithm on the data sets of range image, infrared image and fusion image. ② The detection precision of the model trained by the fusion image dataset is higher than that of the models trained by the infrared image dataset or the depth image dataset. The result shows that the fusion image can give full play to the advantages of the depth image and the infrared image, and is helpful to improve the detection precision of the model. ③ In the six scenes of different degrees of occlusion and multi-scale pedestrian target, the model trained by the improved CornerNet-Squeeze has the lowest pedestrian misdetection rate. ④ Compared with YOLOv 4, the average accuracy of the improved CornerNet-Squeeze algorithm on the COCO2014 pedestrian dataset is improved by 1.1%, and the detection speed is improved by 6.7%. ⑤ The improved CornerNet-Squeeze can effectively detect the small target in the image. The detection capability of the small target is obviously improved.

BACKGROUND Karst groundwater provides drinking water for about 25% of the world's population. As the main type of karst groundwater, underground rivers are an important water supply source for karst areas in Southwest China. It is of great significance to master the water quality, pollution status and human health risk for water resources protection and safety use in southern karst areas. OBJECTIVES To reveal the chemical compositions, pollution degree and health risk of underground river water. METHODS 22 groups of underground river water samples (half inorganic and half organic samples) from the underground river system of Shiziyan in Huixian, Guilin, Guangxi were collected. The concentrations and spatial distribution of 21 inorganic ions and 41 organic indices were analyzed by inductively coupled plasma-mass spectrometry (ICP-MS), ion chromatography (IC) and gas chromatography-mass spectrometry (GC-MS).The single index pollution standard index method was used to evaluate the pollution of 17 inorganic ions and 15 detected organic compounds. The health risk assessment model recommended by the United States Environmental Protection Agency (US EPA) was used to study the human health risk of 10 major pollutants. RESULTS The results showed that: (1) Ca2+ and HCO3- were the dominant ions in the Shiziyan underground river. The concentrations of NH4+, Fe, Al and Mn in the underground river exceeded the groundwater quality standard by 1.33, 1.2, 1.5 and 1.01 times, respectively, and the exceeding points were mostly located in the discharge area of the underground river. 18 organic compounds were detected, of which the detection rates of volatile organic compounds (VOCs), semi volatile organics (SVOCs) and organochlorine pesticides (OCPs) were 18.75%, 30.77% and 91.67% respectively. (2) Compared with the groundwater background values, the underground river water in the study area was slightly-moderately polluted by 10 inorganic indicators and 14 organic compounds. Some sampling points were seriously polluted by NO3-, Fe, Al and Mn, and one sampling point (UR8) was extremely polluted by benzo [a] pyrene. (3) According to the results of health risk assessment, the non-carcinogenic health risks of being exposed to drinking water and for skin exposure were 9.98×10-3 per year for adults and 1.09×10-2 per year for children, and carcinogenic health risks were 1.33×10-7 per year for adults and 2.82×10-7 per year for children, which were within acceptable levels. CONCLUSIONS There are various degrees of inorganic and organic pollution in the study area, but the pollutant indicators do not pose a non-carcinogenic or carcinogenic health risk to the population.

The objective of this research is to study the mechanism of Xiaoyao pill in the treatment of breast hyperplasia by using network pharmacological formula. The active components of Xiaoyao pill were collected and screened in the Pharmacological Database and Analysis Platform of Chinese Medicine (TCMSP), and the included compounds were predicted by TCMSP database. GeneCards database, NCBI gene database and OMIM database were used for screening of breast hyperplasia disease targets. The drug targets and disease targets were selected to make a Venn diagram, and the common targets were used to make a PPI network diagram in the String database. Topological analysis and MCODE cluster analysis were used to screen the core targets and core genes. The key active ingredients were screened in Cytoscape 3.8.0 software. The STRING database was used for GO analysis and KEGG analysis for key targets, and the relevant results were imported into Cytoscape 3.8.0 to draw the component-disease-path path-target network diagram. The active components and targets of Xiaoyao Pills were screened, among which 169 targets were related to breast hyperplasia. Stat3, Akt1, MAPK1, Jun, MAPK3 and other 20 targets were the key targets of this drug in the treatment of breast hyperplasia, and HTR2A, IL2, TOP2A, PCNA, MMP1 were the core genes of this drug in the treatment of breast hyperplasia. Quercetin, Kaempferol, luteolin, naringenin, licochalcone A, 7-methoxy-2-methyl isoflavone, formononetin, and acacetin may be the main active components of Xiaoyao Pill in the treatment of breast hypertrophy. A total of 2328 biological processes were enriched by GO enrichment analysis, with 160 molecular function correlations and 47 cell composition correlations. Enrichment analysis showed that it was associated with 166 pathways, including AGE-RAGE signaling pathway, TNF signaling pathway, IL-17 signaling pathway, Th17 cell differentiation, fluid shear stress and atherosclerosis signaling pathway. The molecular docking verification results showed that the key active ingredients and core targets were well docking. From the perspective of network pharmacology, the potential mechanism and pharmacological substance basis of Xiaoyao pill in the treatment of breast hyperplasia are preliminarily revealed, providing ideas for the follow-up research on Xiaoyao pill in the treatment of gynecological diseases.

In this study, by taking the compression separation process of a biogas project as a research subject, a multistage compression process was simulated using Aspen Plus software. The exergy analysis of the biogas project under multistage compression and adiabatic or isothermal conditions was performed employing the thermodynamic principle. The results showed that the biogas exergy increased with pressure during the compression process and correspondently decreased in the interstage cooling process. Further, the compression series increased with the increase in efficiency, but the increase was gradual. The results of the example study of the four-stage compression process are as follows: the process exergy increased by ~83.07 kW, the process exergy efficiency was ~75.56%, and the recovery exergy potential was ~12.6 kW. In this study, the allocation of compression ratios and the selection of compression stages within the multistage compression process were analyzed by Aspen Plus was used to analyze., This analysis can ultimately help others design efficient multistage compression systems that reduce energy losses.

In order to solve the problems of slow detection speed and low detection precision of the existing deep learningbased coal and gangue target detection methods, an improved YOLOv5s model is proposed and applied to coal and gangue target detection. The YOLOv5s model is improved by embedding selfcalibrated convolutions (SCConv) in the Backbone area of YOLOv5s model as the characteristic extraction network, which can better fuse multiscale characteristic information. Because the size of coal and gangue is too small compared with the whole image, the Neck area of YOLOv5s model is appropriately simplified, and the 19×19 characteristic map branches suitable for detecting larger size objects are deleted, thus reducing model complexity and improving the realtime detection performance. The anchor box obtained by clustering with Kmeans algorithm is linearly scaled to improve the model detection precision. The experiment of coal and gangue target detection based on improved YOLOv5s model shows that compared with YOLOv5s model, the improved YOLOv5s model can detect the corresponding coal and gangue accurately. The size of improved YOLOv5s model is reduced by 1.57 MB, the frame rate is increased by 2.1 frames/s, and the average precision is improved by 1.7%, indicating that the improved YOLOv5s model has improved both detection precision and detection speed.

The underground coal mine environment is dim, humid and dusty, and the collected video images are blurred, which makes it difficult to identify the longitudinal tear of the conveyor belt. The existing research results only focus on whether there is longitudinal tear, without involving the location of tear damage and trend tracking. This paper proposes a method for longitudinal tearing detection of belt conveyors based on multi-channel linear laser. This method uses a mine intrinsically safe structured light emitter to project multiple linear lasers onto the surface of the conveyor belt, and uses a mine intrinsically safe industrial camera to take linear laser stripe images. By extracting the center line of the laser stripe and analyzing its characteristics, this method determines whether there is longitudinal tear damage in a single frame image. When there is damage, this method can search for damage boundary points and calculate damage width and depth characteristic values. The method fuses multi-frame image detection results and speed sensor values to calculate the complete longitudinal tear damage length, average width and average depth. By detecting the position of the marker on the conveyor belt, the method can locate the longitudinal position of the tear damage and locate the lateral position by finding the bit width ratio of the starting point of the damage on the conveyor belt. And the damage trend tracking is realized based on the longitudinal position. The method is tested by setting the conveyor belt longitudinal tear damage length to 0.73, 0.95 m, the average width to 0.01 m, the average depth to 0.008 m, and the sampling rate to 25 frames/s. The results show that the method can accurately detect whether the belt conveyor has longitudinal tears, the average error of damage length calculation is 0.06 m, the average error of damage average width and average depth calculation is 0.001 m, and the error of longitudinal positioning is less than 0.1 m. It can determine the development trend of longitudinal tears accurately.

A floating foundation vibration reduction system with an air spring as a vibration isolation element has been widely used in the foundation of large ultra-precision instruments. With the excellent vibration isolation performance of the air spring, its complex dynamic nonlinear behavior is always a research difficulty. In this paper, a dynamic model of a floating foundation vibration reduction system based on the restoring force of air spring is derived. The structure of the recurrent convolution neural network (RCNN) is proposed based on combining the working characteristics of a convolution neural network and a long short-term memory neural network, and the dynamic model of a floating foundation vibration reduction system is established with the restoring force of the air spring calculated by the RCNN as the input. Finally, a test experiment was designed to compare the dynamic characteristics of the traditional numerical model and three deep neural network models in the floating foundation. The results show that convolution neural network, long short-term memory, and RCNN models could predict the vibration response of floating foundation vibration reduction system, and the RCNN model had better performance for a floating foundation.

Orthodontic treatment for dentofacial deformity is fundamental throughout the entire management process of cleft lip and palate. Orthodontist is one of those who are indispensable in the comprehensive multidisciplinary cleft team. Cleft lip and palate patients have unique dentofacial characteristics which makes the treatment goals and strategies different from those of other patients in different stages. For newborns with cleft lip and palate, the main treatment includes presurgical orthopedics. For patients in their primary dentition stage, the treatment mainly focuses on the prevention of bad oral habits and severe malocclusion. For those in their mixed dentition stage, the treatment mainly consists of dentition preparation for alveolar bone grafting and skeletal growth modification. For patients in their permanent dentition stage, treatment strategies include orthodontic camaflouge treatment, combined orthodontic-orthognathic approach and segmental alveolar distraction osteogenesis. In addition to routine orthodontic treatment, orthodontists should pay special attention to managing the compliance of cleft lip and palate patients with unique psychological characteristics. By summarizing the state-of-art cleft lip and palate orthodontic care in the multidisciplinary team, this review aims to involve more orthodontic clinicians to join in the modern biopsychosocial medical practice of cleft lip and palate team approach and to improve the standard of care for cleft lip and palate patients.

Objective To elucidate the role of signal transducer and activator of transcription 3 on orthodontic tooth movement, aiming at providing evidence for improving orthodontic bone modeling and remodeling. Methods Orthodontic tooth movement (OTM) models were established in 8-week-old Wistar rats, which were divided into 2 groups: the control group (tooth movement) and the test group (tooth movement with local injection of STAT3 inhibitor stattic). Rats were sacrificed on day 7 and 14. Micro-CT scanning was conducted to measure bone volume/tissue volume (BV/TV), trabecular number (Tb.N), trabecular thickness (Tb.Th), trabecular separation (Tb.Sp), and bone mineral density (BMD), and the amount of tooth movement of the specimens. The mouse preosteoblastic cell line MC3T3-e1 and mononuclear macrophagic leukemia cell line RAW264.7 were cocultured in Transwell® culture plates and divided into the control group (blank) and the test group (STAT3 inhibitor stattic was added). Alkaline phosphatase (ALP) staining and tartrate-resistant acid phosphatase (TRAP) staining were carried out to reveal osteoblastic and osteoclastic differentiation, respectively. qRT-PCR was performed to evaluate mRNA expression levels of the receptor activator of nuclear factor-κB ligand (RANKL) and osteoprotegerin (OPG) in the MC3T3-e1 cells. Results Compared with the control group, in the test group, the alveolar bone at the OTM site showed a significant decrease in the BV/TV, Tb.N, Tb.Th, and BMD indexes and a significant increase in Tb.Sp on day 14, while there was no significant difference in the above indexes between the two groups on day 7. The amount of tooth movement was significantly smaller in the test group on day 7 but showed no difference on day 14. ALP staining and TRAP staining revealed weakened osteoblastic and osteoclastic differentiation in the test group. qRT-PCR demonstrated the inhibitor inhibited the mRNA expression of RANKL and OPG and increased the mRNA ratio of RANKL/OPG in osteogenic precursor cells. Conclusion Suppression of STAT3 activation leads to inhibition of both osteoblastic and osteoclastic differentiation, resulting in lowered tooth movement and catabolic effects on alveolar bone. STAT3 may play an important role in orthodontic bone modeling and bone remodeling.

The signal distortion caused by the limited bandwidth of Light Emitting Diode (LED) and its nonlinear electro-optic conversion severely limit the transmission performance of Visible Light Communication (VLC). Traditional Message Passing Algorithm (MPA) has limited ability to resist signal nonlinear distortion in Sparse Code Multiple Access (SCMA) -VLC. In order to solve the above problems, the paper proposes a Convolutional Neural Network (CNN) receiver, which can effectively improve the anti-nonlinear distortion ability of SCMA-VLC system by feature extraction, classification and judgment of the received signal. The results show that, in the case of strong nonlinear distortion, CNN receiver has better Bit Error Rate (BER) performance than MPA receiver, which effectively expands the dynamic range of bias voltage and reduces the Signal-to-Noise Ratio (SNR) requirements of the system.

BACKGROUND With the wide application of PAEs in plastic greenhouse and plastic film mulching cultivation techniques, the pollution of diethylhexyl phthalate (DEHP) in agricultural soils has become widespread in China. OBJECTIVES To quantitatively reveal the release of DEHP from plastic film and the distribution characteristics of DEHP concentration in mulched soil, red soil and tobacco films in the Yunnan Karst Plateau. METHODS Field experiments were conducted to simulate the mulched soil environment, and the DEHP contents in agricultural film and soil media were determined by Gas Chromatography-Mass Spectrometry. RESULTS The maximum release of DEHP from plastic film cover in undisturbed soil was 13.57mg/kg. The average DEHP (10.83mg/kg) released from plastic film covered with biological inhibitors was slightly higher than that from uncovered soil (10.77mg/kg). The releases of DEHP from plastic film included two stages of slow release and concentrated steep increase. The total release increased with time. DEHP concentrations in undisturbed soil ranged from 0.17 to 3.74mg/kg and those in soil with biological inhibitors ranged from 0.34 to 4.29mg/kg. The DEHP levels were within the detection concentration range of phthalate esters (PAEs) in mulched farmland soil at home and abroad. The contents of DEHP in soils increased first and then decreased with time. CONCLUSIONS DEHP in soil mainly comes from the release of DEHP in plastic film. It is concluded that DEHP does not accumulate in red soils of the Karst Plateau within a short period. Reasonable arrangement of crop mulching can effectively reduce organic pollution in soil.

BACKGROUND Sample testing is important for studying hydrogeology, engineering geology and environmental geology in Karst areas. The inconvenience of transportation, the difficulty of sample shipping and the delayed sample analyses by testing laboratory in Karst areas lead to the lag of sample testing in varying degrees. However, existing research cannot effectively explain the impact of test lag on the properties of Karst water samples. OBJECTIVES To make progress on this scientific problem, a typical Karst spring in Xuanwei City, Yunnan Province was selected as research object. METHODS Ten indicators of K+, Na+, Ca2+, Mg2+, Cl-, SO42-, HCO3-, pH, NO3- and CO2(fs) of spring water samples were determined by Ion Chromatography and Atomic Emission Spectrometry. These samples were collected at the same time and the same place according to the time series of 1d, 3d, 5d, 7d, 9d, 11d, 13d, 15d, 17d, 35d, 50d, 75d. The effect of test lag on the properties of Karst water samples was discussed. RESULTS The results show that test lag had certain influence on analytical results. During 75 days Karst water sample placement, the uncertainty values of type A standard of the indicators were 0.02-1.83, and uncertainty values of HCO3- and Ca2+ were significantly higher than other indicators. Shapiro-Wilk normality test results showed that the pH, K+, Mg2+, Cl-, and NO3- follow normal distribution. As time elapsed, the relative deviation ranged from 0% to 57.38%. The relative deviation of pH, Ca2+, SO42- and NO3- was within the allowable error range. Overall, the mean content and coefficient of variation of ten indicators showed significant negative correlation (Spearman correlation coefficient is -0.709, P < 0.05), and the variation coefficient decreased as follows:Na+, K+, CO2(fs), Mg2+, Cl-, SO42-, Ca2+, HCO3-, pH, NO3-. These results revealed that the influence of test lag on different indicators was different, especially on the indicators with low mass fraction. The analysis of indicators changing over time showed that the change process of water quality of the water sample could be divided into five stages:stationary stage (0-3 day), preliminary change stage (3-5 day), mixed change stage (5-17 day), potential impact stage of bacteria (17-35 day) and relative equilibrium stage (35-75 day). Among them, bacterial action and carbonic acid balance were the two most important mechanisms during Karst water sample placement. CONCLUSIONS The research results can provide technical support for improving the testing precision of water samples in Karst regions.

Using severe accident analysis program MELCOR, the small break loss of coolant accident (SBLOCA) analysis model was established for a marine reactor. The release and migration of radionuclides were analyzed during a severe accident induced by SBLOCA. The analysis of the hydrogen source term release showed that the maximum hydrogen release amount was 248.567 kg, and the hydrogen release amount accounted for less than 4% of the air volume. So, there would be no danger of hydrogen explosion accidents. The research mainly focused on the behaviors of the release, the transport, the retention, and the final distribution of inert gases represented by Xe, volatile gases represented by CsI, and nonvolatile nuclides represented by Ba. The results showed that the reactor core exposed completely with a lagging by 510 s and the initial release time of nuclides was lagged by 1916 s. The release shares of Xe in the primary circuit system, the containment, and the environment were 0.013%, 0.06%, and 32.71%, respectively. Also, Ba shared 0.016%, 0.0032%, and 3.28%, respectively, and CsI shared 0.0145%, 0.0012%, and 2.845%, respectively.

BACKGROUND In recent years, reports of the detection of PAHs in groundwater have gradually increased, but research on PAHs in groundwater of major hydrogeological units in China is not being conducted. OBJECTIVES To study and compare the distribution characteristics of PAHs in groundwater under different hydrogeological conditions, using a total of 82 samples of shallow pore water and Karst groundwater samples collected in the Huabei plain, the Pearl River Delta plain, and the Southwestern Karst area. METHODS Gas Chromatography-Mass Spectrometry (GC-MS) was used to test PAHs in groundwater samples, and statistical methods were used to compare the detection frequency, concentration and composition of PAHs in the three different areas. RESULTS 16 PAHs were detected and each PAH was detected in at least one sample. The highest detection rate of PAHs was chrysene (6.10%). The PAH with the highest concentration was naphthalene (5.41 μg/L). Only the concentration of benzo(a)pyrene exceeded the Class Ⅲ limit in the standard for groundwater quality, and the over-standard rate was 2.44%. The PAHs in groundwater are mainly 2-4 rings, but the composition of PAHs in the three regions was different. The relative proportion of 4-rings PAHs in the northern pore water was high, accounting for 52.48%, whereas the pore water in the South and the Karst water in the Southwest were dominated by 3-rings (56.60%) and 2-rings (95.66%), respectively. CONCLUSIONS The main cause of contamination of PAHs in Northern pore water was by combustion. The PAHs contamination in the Southern pore water was related to the industrial layout of the Pearl River Delta, whereas the PAHs of Qujing Karst water were mainly affected by atmospheric precipitation. The detection differences of PAHs in different districts were related to their physicochemical properties, hydrogeological conditions, pollution sources, meteorological and hydrological factors. The results provide basic data support for groundwater PAHs pollution monitoring and the formulation of a groundwater related standard in China.

Objective The objective of this study was to compare the early clinical effects of zirconia all⁃ceramic crowns using two different impression methods. Zirconia ceramic crowns were produced using digital models based on either a silicone rubber impression perfusion model in vitro or a 3D mouth scanner. Methods A total of 50 patients with a planned restoration of the first permanent molar with zirconia all⁃ceramic crowns after root canal therapy were se⁃ lected and randomly divided into two groups: a digital impression by intraoral 3D scanning group and a digital impres⁃ sion by extraoral scanning after silicone rubber impression group. Zirconia all ⁃ceramic crowns were created by CAD/ CAM in both groups. Marginal adaptation, proximal contact, and occlusal contact were compared between groups. Re⁃ sults There was no significant difference between the two groups in marginal adaptation (P > 0.05). For proximal con⁃ tact and occlusal contact, no significant differences regarding the number of cases for the criteria of level A and level B were found between two groups (P > 0.05), while the misfit value in level B was smaller in the first group than in the second group (P < 0.05). Conclusion Zirconia all ⁃ ceramic crowns with intraoral 3D scanning show excellent early clinical performance.

Electrohydrodynamic jet 3D printing is an emerging and promising technology of microand nano-scale additive manufacturing with a low cost and high resolution, as well as a wide range of printed materials. However, due to the high printing speed and small standoff height between the nozzle and the substrate, it is especially difficult to directly observe and measure the printed patterns. Furthermore, there are many process parameters that affect the printing accuracy and quality, among which each parameter is coupling and interacting. This paper proposed a method of controlling the accuracy and quality of printed patterns based on the regulation of the shape and size of the Taylor cone by varying the process parameters. A theoretical model was then derived and established that describes the relationship between the line width printed with process parameters, printed material, and used substrate. Through the systematic experimental study, the influences and rules of the printing process parameters on the Taylor cone and printed patterns were revealed; Furthermore, the ideal jet printing window for the same nozzle was optimized. Finally, the feasibility and validity of the experimental results were demonstrated by the typical engineering cases, and a pattern of minimum line width of 3 μm was achieved with the nozzle diameter of 60 μm. The proposed method and experimental results provide a basis for further improving the accuracy, quality, and stability for electrohydrodynamic jet 3D printing, and the method offers a feasible solution for simplification and easy operation of actual 3D printing.

TRAPP (transport protein particle) is a large, highly conserved, multi-subunit complex. Four types of TRAPP complexes (I, II, III and most recently IV) have been identified in Saccharomyces cerevisiae. Studies on the roles of TRAPP II, TRAPP III and TRAPP IV specific subunits (Trs130, Trs85 and Trs33) have demonstrated that TRAPP II, TRAPP III and TRAPP IV activate the small GTPases that regulate autophagy. Up to now, the roles of the common TRAPP subunits have been well studied in vesicle transport. However, the roles of the common TRAPP subunits and their relationship to Ypt/Rab GTPases in autophagy are not clear. In this paper, we examined Trs20, Trs23, Trs31, and Bet5 (the common TRAPP subunits), which are required for starvation-induced autophagy and the cytoplasm-to-vacuole targeting (Cvt) pathway. During autophagy, GFP-Atg8 accumulates as single or multiple dots and is not recruited into the pre-autophagosomal structures (PAS) in trs20ts, trs23ts, trs31ts and bet5ts mutant cells. Furthermore, these dots are linked to the endoplasmic reticulum in mutant cells. Additionally, overexpression of Ypt1, but not Ypt31, suppresses the autophagy defect in trs20ts, trs23ts, trs31ts and bet5ts mutant cells. Based on these results, we concluded that Trs20, Trs23, Trs31, and Bet5 are required for autophagy, and that these common TRAPP subunits regulate autophagy partially through GTPase Ypt1, but not Ypt31.

Based on the of theory heat conduction and thermal-elasticity,simulated the braking process of mine hoist. The changing laws of the boundary condition on the brake disc’s surface during braking were analyzed and the computing method of the convective coefficient was discussed emphatically. According to variable material properties and the actual dimension of brake disk,a 3-dimensional cycle-symmetric model of brake disk in mine hoist was established and the temperature and thermal stress distribution was researched under the different braking conditions. The article discussed the calculation method considering thermal stress,and analyzed and compared each method’s advantage with disadvantage. The results indicate that the temperature and stress distribution of brake disk are closely related to the braking initial velocity and braking acceleration. The simulation provides an important reference for the optimization of lifting speed and braking acceleration,and the design and development of high-performance brake system.

This case report describes the orthodontic treatment of a 20 year-old female who presented with a severe anterior open bite, increased lower facial height and mandibular asymmetry. The patient was diagnosed with a Class I skeletal pattern but a Class III dental relationship, an anterior and unilateral posterior open bite, a canted posterior occlusal plane, a clockwise rotation and vertical growth pattern of the mandible incorporating a chin deviation to the right.

In this paper, the discontinuous Galerkin (DG) method is applied to solve the governing equations of the dispersed two-phase flow with the two-fluid Euler/Euler approach. The resulting governing equations are simple in form and the solution process is very natural. The characteristics of the gas-particle two-phase flow in an engine nozzle are mainly analyzed, and the impacts of the particle mass fraction and particle size on the flow field and engine performance are evaluated. Because of the addition of particles, the gas flow field undergoes significant modifications. Increase in the mass fraction leads to a significant thrust loss in the gas phase, and the impact of the particles on the gas phase could be substantial. Therefore, a quantitative study of thrust loss in the nozzle due to the particle impact is made. It is found that the gas thrust in the two-phase flow is reduced, but the total thrust of the two-phase flow increases to a certain extent.

Magnetohydrodynamics (MHD)-based global space weather models have mostly been developed and maintained at academic institutions. While the “free spirit” approach of academia enables the rapid emergence and testing of new ideas and methods, the lack of long-term stability and support makes this arrangement very challenging. This paper describes a successful example of a university-based group, the Center of Space Environment Modeling (CSEM) at the University of Michigan, that developed and maintained the Space Weather Modeling Framework (SWMF) and its core element, the BATS-R-US extended MHD code. It took a quarter of a century to develop this capability and reach its present level of maturity that makes it suitable for research use by the space physics community through the Community Coordinated Modeling Center (CCMC) as well as operational use by the NOAA Space Weather Prediction Center (SWPC).

According to theory of nonlinear vibration and Higher theory of plates and shells,the welding residual stress influence on stability of solution of nonlinear thin rectangular plate was studied to choose nonlinear rectangular thin plate possessed the welding residual stress as subject investigated. The conclusion which the stable and unstable regions of periodic solution of nonlinear rectangular thin plate possessed the welding residual stress has with the welding residual stress and change was gained. The conclusion which in different frequency ranges,the welding residual stress effects on stability of periodic solutions of different was obtained. The conclusion which the welding residual stress on the whole bring to reduce the stable region of periodic Solutions. The conclusion has certain guiding significance for the design of nonlinear rectangular thin plate possessed the welding residual stress.

Taking the slewing gear of anti- radiation hydraulic excavator as study object,the 3D model of slewing gear is established by using Pro / E,the correct meshing parameters of slewing gear meshing transmission are determined,and the slewing gear mesh dynamics simulation is carried on in ADAMS. The simulation results of rotating speed of gear ring,meshing force and the frequency of the meshing force are much the same as the theoretical calculation value,the accuracy and reliability of the model are verified. Finally,the influences of different rotation speed and torque on meshing force are analyzed. The simulation results can provide the basis of the calculation for strength check and optimization design of slewing gear.

Research on hospital logistics management is conducive to improving the efficiency of logistics operations and promoting the economic development of the hospital. In order to solve the problem of logistics management affected by a large number of uncertainties and multi-state factors, a set of 12-factor research index system was constructed from three aspects: basic skills, element skills, and task skills, and at the same time, the level of evaluation indicators was determined. In the interval, a research method of hospital logistics management based on cloud model is proposed. And according to Monte Carlo simulation, find out specific sensitive factors. Finally, the effectiveness and feasibility of the method is verified through the logistic operation and maintenance examples of 4 Grade-A public hospitals in Wuhan.

The research on digging resistances is the key to designing the grab, improving the grab’s structure and realizing the automatic flat digging of grab dredger. This article focuses on the mechanical analysis and experimental research of grab’s flat digging combining with theoretical calculation and experiments in dredging process. The theoretical digging resistances in both horizontal and vertical directions have been investigated in mathematical model. With the help of flat digging experiments, the forces on hoist rope and closing rope have been recorded. Then, work out the horizontal and vertical digging resistances based on moment balance. Since a good agreement is achieved between the theoretical calculations with the corresponding independent experimental results, the research has been verified and provides technical support for flat digging in dredging process.

In view of problems of no representation and practicality because that traditional separation system of lump coal and gangue based on image gray information only randomly selects samples of coal and gangue, the paper researched an automatic separation system of lump coal and gangue based on image gray information which emphasized in practicality and system. At first, it selected six representative lump coals and gangues in term of material, texture feature and cleanness, and analyzed distribution law of image gray of the six lump coals and gangues according to certain group mode under conditions of strong light, natural light and energy-saving lamp light and made the distribution law as basis of object recognition of computer, so as to realize automatic separation for lump coal and gangue. The test result showed that using obvious differences of image gray information between lump coal and gangue to make visual distinction can realize automatic separation under special conditions.

Based on unsteady flow theory, supported by the theories of mine ventilation, fluid mechanics and infiltration flow through porous media, a mathematical model of fluctuating airflow in the porous media of goafs of mines is established. Features of distribution of flow field in goaf when airflow fluctuating are researched by numerical simulation, and the distribution of flow field is tested with the help of an experiment model which was designed and done by the authors. The results show that the numerical simulation and experiment agree well. This shows that the mathematical model of flow field of porous media in goaf of mine established in the paper can be used to research distribution of flow field in goaf and flow shift law.

Laser peen forming (LPF) is a pure mechanical forming method through accumulated plastic strain, which has been successfully applied in wing components. Experimental investigation has been performed to understand the effect of process parameters such as constraint conditions, sheet thickness and laser energy on surface morphology and bending deformation of 2024-T3 thin sheets of dimensions of 76 mm ×19 mm (length × width). The research results indicated that bulges on the aluminum foil were generated at the bottom surface and not generated at the topmost surface. It was different for transition value of two-way bending deformations of thin sheets after LPF with different constraint conditions. Remain flat thicknesses of thin sheets after LPF were about 1 mm ~ 2 mm for 20 J, 25 J and 30 J. Arc heights and curvatures of 3 mm thickness sheets increased with laser energy and those of 2 mm thickness sheets only made little change. It was found that convex deformation, flat, concave deformation and laser deep drawing for thin sheets with different thicknesses after LPF.

Mixed ownership system reform is the focus of current state asset reform, and the reform efficiency of power enterprise attracts worldwide attention. This paper discusses the mixed ownership system reform of power enterprise from the angle of corporate governance. First of all, this paper will analyze the corporate governance situation and existing problems from ownership structure and other two aspects. Second, the corporate governance model of power enterprise is constructed. Third, governance optimization measures will be put forward and the conclusion is obtained. This paper hopes to provide certain reference for corporate governance of mixed ownership system reform of Chinese power enterprises.

A novel trust model for P2P networks was proposed,in which the trust value of a given peer was computed using its local trust information and recommendation from other nodes. A generic method for quantifying and updating the credibility of a recommender was also put forward. With regard to risk element,the risk was quantified by informa-tion entropy and so trust degree and uncertainty degree was presented in uniform form. Subsequent experimental results show that,compared to some trust models,the proposed model is more robust on trust security problems and more ad-vanced in successful transaction rate. So the trust model can perform much better especially in helping peers establish trust relationships in open P2P networks.

Telecommunication circles are groups of similar customers in telecommunication networks. Mining such circles provides with telecommunication operators great value in developing prospective customers while retaining old ones. However, most of the existing community detecting algorithms utilize mainly the structure of the complex network and ignore the strength of relationship. This paper improves the classic CPM (Clique Percolation Method) algorithm by taking into account both the call record and short messages, and proposes a new algorithms called SR_CPM (Strengthened Relationship CPM). The new algorithm is applied to telecommunication networks and demonstrates superior effectiveness over CPM.

The domestic and overseas studies of redundant multifeatures and noise in dimension reduction are insufficient, and the efficiency and accuracy are low. Dimensionality reduction and optimization of characteristic parameter model based on improved kernel independent component analysis are proposed in this paper; the independent primitives are obtained by KICA (kernel independent component analysis) algorithm to construct an independent group subspace, while using 2DPCA (2D principal component analysis) algorithm to complete the second order related to data and further reduce the dimension in the above method. Meanwhile, the optimization effect evaluation method based on Amari error and average correlation degree is presented in this paper. Comparative simulation experiments show that the Amari error is less than 6%, the average correlation degree is stable at 97% or more, and the parameter optimization method can effectively reduce the dimension of multidimensional characteristic parameters.

Locality preserving projection (LPP) retains only partial information, and category information of samples is not considered, which causes misclassification of feature extraction. An improved locality preserving projection algorithm is proposed to optimize the extraction of growth characteristics. Firstly, preliminary dimensionality reduction of sample data is constructed by using two-dimensional principal component analysis (2DPCA) to retain the spatial information. Then, two optimized subgraphs are defined to describe the neighborhood relation between different categories of data. Finally, feature parameters set are obtained to extract local information of samples by improved LPP algorithm. The experiments show that the improved LPP algorithm has good adaptability, and the highest SVM classification accuracy rate of this method can reach more than 96%. Compared with other methods, the improved LPP has superior optimized performance in terms of multidimensional data analysis and optimization.

Some of our recent studies on hohlraum physics are presented, mainly including simulation study on hohlraum physics experiments on SGIII prototype, the design of Au + U + Au sandwich hohlraum for ignition target, and an initial design of elliptical hohlraum and pertinent drive laser power in order to generate an ignition radiation profile.

Abstract Background Several peripheral proteins that might be useful for detecting the presence of ectopic pregnancy (EP) have been evaluated, but none have been proven entirely useful in the clinic. We investigated the presence and the possible changes in circulating molecules that distinguish between normal intrauterine pregnancy (IUP) and tubal ectopic pregnancy. Methods Non-pregnant women during the menstrual cycle, women with IUP, and women with tubal EP after informed consent. Serum levels of 17β-estradiol (E2), progesterone (P4), testosterone (T), beta-human chorionic gonadotropin (β-hCG), vascular endothelial growth factor-A (VEGF-A), placental growth factor (PIGF), and a distintegrin and metalloprotease protein 12 (ADAM12) were analyzed. Receiver operating characteristic analysis was used to assess the diagnostic discrimination of EP and gestational age-matched IUP. Results E2, P4, PIGF, and ADAM12 levels increased and β-hCG decreased throughout IUP. E2 and VEGF-A levels were significantly different between women with tubal EP and IUP. However, using a serum β-hCG cut-off of less than 1000 mIU/mL, P4 was significantly lower in women with tubal EP compared to IUP. Although E2 was inversely correlated with VEGF-A in women in the early stages of IUP, E2 was not correlated with VEGF-A in women with EP prior to tubal surgery. There were no significant differences in either PIGF or ADAM12 alone between women with tubal EP or IUP. Although no significant correlations were seen between E2 and PIGF or P4 and ADAM12 in women in the early stages of IUP, E2 was positively correlated with PIGF and P4 was positively correlated with ADAM12 in women with EP prior to tubal surgery. Our studies defined associations but not causality. Conclusions Individual measurements of serum E2 or VEGF-A levels are strongly related to early pregnancy outcomes for women with IUP and EP, and pregnancy-associated E2 and VEGF-A levels provide diagnostic accuracy for the presence of tubal EP. This study demonstrates that correlation analysis of E2/VEGF-A and E2/PIGF serum levels may be able to distinguish a tubal EP from a normal IUP.

Abstract Over-activation of AMPARs (α−amino-3-hydroxy-5-methylisoxazole-4-propionic acid subtype glutamate receptors) is implicated in excitotoxic neuronal death associated with acute brain insults, such as ischemic stroke. However, the specific molecular mechanism by which AMPARs, especially the calcium-impermeable AMPARs, induce neuronal death remains poorly understood. Here we report the identification of a previously unrecognized molecular pathway involving a direct protein-protein interaction that underlies GluR2-containing AMPAR-mediated excitotoxicity. Agonist stimulation of AMPARs promotes GluR2/GAPDH (glyceraldehyde-3-phosphate dehydrogenase) complex formation and subsequent internalization. Disruption of GluR2/GAPDH interaction by administration of an interfering peptide prevents AMPAR-mediated excitotoxicity and protects against damage induced by oxygen-glucose deprivation (OGD), an in vitro model of brain ischemia.

Abstract Background Fractalkine/CX3CL1 and its cognate receptor CX3CR1 are abundantly expressed in the CNS. Fractalkine is an unusual C-X3-C motif chemokine that is important in neuron-microglial communication, a co-receptor for HIV infection, and can be neuroprotective. To assess the effects of fractalkine on opiate-HIV interactive neurotoxicity, wild-type murine striatal neurons were co-cultured with mixed glia from the striata of wild-type or Cx3cr1 knockout mice ± HIV-1 Tat and/or morphine. Time-lapse digital images were continuously recorded at 20 min intervals for up to 72 h using computer-aided microscopy to track the same cells repeatedly. Results Co-exposure to Tat and morphine caused synergistic increases in neuron death, dendritic pruning, and microglial motility as previously reported. Exogenous fractalkine prevented synergistic Tat and morphine-induced dendritic losses and neuron death even though the inflammatory mediator TNF-α remained significantly elevated. Antibody blockade of CX3CR1 mimicked the toxic effects of morphine plus Tat, but did not add to their toxicity; while fractalkine failed to protect wild-type neurons co-cultured with Cx3cr1-/--null glia against morphine and Tat toxicity. Exogenous fractalkine also normalized microglial motility, which is elevated by Tat and morphine co-exposure, presumably limiting microglial surveillance that may lead to toxic effects on neurons. Fractalkine immunofluorescence was expressed in neurons and to a lesser extent by other cell types, whereas CX3CR1 immunoreactivity or GFP fluorescence in cells cultured from the striatum of Cx3cr1-/- (Cx3cr1GFP/GFP) mice were associated with microglia. Immunoblotting shows that fractalkine levels were unchanged following Tat and/or morphine exposure and there was no increase in released fractalkine as determined by ELISA. By contrast, CX3CR1 protein levels were markedly downregulated. Conclusions The results suggest that deficits in fractalkine-CX3CR1 signaling contribute to the synergistic neurotoxic effects of opioids and Tat. Importantly, exogenous fractalkine can selectively protect neurons from the injurious effects of chronic opioid-HIV-1 Tat co-exposure, and this suggests a potential therapeutic course for neuroAIDS. Although the cellular mechanisms underlying neuroprotection are not certain, findings that exogenous fractalkine reduces microglial motility and fails to protect neurons co-cultured with Cx3cr1-/- mixed glia suggest that fractalkine may act by interfering with toxic microglial-neuron interactions.

Abstract Background Reverse transcription PCR (RT-PCR) and real time RT-PCR (rRT-PCR) have been indispensable methods for influenza surveillance, especially for determination of avian influenza. The movement of testing beyond reference lab introduced the need of quality control, including the implementation of an evaluation system for validating personal training and sample proficiency testing. Methods We developed a panel with lysates of seasonal influenza virus (H1N1, H3N2 and B), serials of diluted H5N1 virus lysates, and in-vitro transcribed H5 hemaglutinin (HA) and an artificial gene RNAs for RT-PCR and rRT-PCR quality control assessment. The validations of stability and reproducibility were performed on the panel. Additionally, the panel was implemented to assess the detection capability of Chinese human avian influenza networks. Results The panel has relatively high stability and good reproducibility demonstrated by kappa's tests. In the implementation of panel on Chinese human avian influenza networks, the results suggested that there were a relatively low number of discrepancies for both concise and reproducibility in Chinese avian influenza virus net works. Conclusions A quality control panel of RT-PCR and real-time RT-PCR for avian influenza A (H5N1) surveillance network was developed. An availably statistical data, which are used to assess the detection capability of networks on avian influenza virus (H5N1), can be obtained relatively easily through implementation of the panel on networks.