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Snoring is one of the cardinal presentations of obstructive sleep apnea (OSA) and is more common than OSA. Abundant evidence has suggested a robust association between OSA and coronary artery disease (CAD). However, whether or not snoring alone is related to a higher risk of CAD is unknown. This study systematically reviewed observational studies with meta-analysis to evaluate the linkage between snoring and CAD. We searched PubMed and Embase and retrieved 13 articles focusing on the relationship between snoring and CAD. These articles included a total of 151,366 participants and 9099 CAD patients. Quantitative analysis indicated that snoring was associated with a 28% (RR: 1.28, 95% CI: 1.13 to 1.45, P < 0.001) increase in the risk of developing CAD. Snorers are exposed to a 28% increased risk for CAD. Although the association may be partly mediated through OSA, most snorers are not affected by apnea. Given the high prevalence of snoring and the disease burden of CAD in the general population, screening for snoring may be worthwhile for the early prevention of CAD.

Aims: Using specials wearable sensors, we explored changes in gait and balance parameters, over time, in elderly patients at high risk of diabetic foot, wearing different types of footwear. This assessed the relationship between gait and balance changes in elderly diabetic patients and the development of foot ulcers, in a bid to uncover potential benefits of wearable devices in the prognosis and management of the aforementioned complication. Methods: A wearable sensor-based monitoring system was used in middle-elderly patients with diabetes who recently recovered from neuropathic plantar foot ulcers. A total of 6 patients (age range: 55–80 years) were divided into 2 groups: the therapeutic footwear group (n = 3) and the regular footwear (n = 3) group. All subjects were assessed for gait and balance throughout the study period. Walking ability and gait pattern were assessed by allowing participants to walk normally for 1 min at habitual speed. The balance assessment program incorporated the “feet together” standing test and the instrumented modified Clinical Test of Sensory Integration and Balance. Biomechanical information was monitored at least 3 times. Results: We found significant differences in stride length (p < 0.0001), stride velocity (p < 0.0001), and double support (p < 0.0001) between the offloading footwear group (OG) and the regular footwear group on a group × time interaction. The balance test embracing eyes-open condition revealed a significant difference in Hip Sway (p = 0.004), COM Range ML (p = 0.008), and COM Position (p = 0.004) between the 2 groups. Longitudinally, the offloading group exhibited slight improvement in the performance of gait parameters over time. The stride length (odds ratio 3.54, 95% CI 1.34–9.34, p = 0.018) and velocity (odds ratio 3.13, 95% CI 1.19–8.19, p = 0.033) of OG patients increased, converse to the double-support period (odds ratio 6.20, 95% CI 1.97–19.55, p = 0.002), which decreased. Conclusions: Special wearable devices can accurately monitor gait and balance parameters in patients in real time. The finding reveals the feasibility and effectiveness of advanced wearable sensors in the prevention and management of diabetic foot ulcer and provides a solid background for future research. In addition, the development of foot ulcers in elderly diabetic patients may be associated with changes in gait parameters and the nature of footwear. Even so, larger follow-up studies are needed to validate our findings.

Colorectal anastomoses in patients with colorectal cancer carry a high risk of leakage. Indocyanine green fluorescence angiography (ICG-FA) is a new technique that allows surgeons to assess the blood perfusion of the anastomosis during operation. This meta-analysis aimed to evaluate whether ICG-FA could prevent anastomotic leakage (AL) in colorectal surgery. Four databases (PubMed, Embase, Web of Science, and Cochrane Library) were searched to identify suitable literatures until March 2020 that compared AL rates between intraoperative use and non-use of ICG-FA in colorectal surgery for cancer. The Review Manager 5.3 software was used to perform the statistical analysis. Evaluation of articles quality and analysis for publication bias were also conducted. Thirteen studies of 4037 patients were included in the meta-analysis. The study included 1806 patients in the ICG group and 2231 patients in the control group. The pooled incidence of AL in ICG group was 3.8% compared with 7.8% in control group. There was a significant difference in AL rate with or without use of ICG-FA (OR 0.44; 95% CI 0.33–0.59; P < 0.00001). Reoperation rates were 2.6% and 6.9% in ICG and control groups, respectively. Application of intraoperative ICG-FA was associated with a lower risk of reoperation (OR 0.39; 95% CI 0.16–0.94; P = 0.04). Overall complication rate was 15.6% in the ICG group compared with 21.2% in the control group. Overall complications were significantly reduced when using ICG-FA (OR 0.62; 95% CI 0.47–0.82; P = 0.0008). Mortality rate was not statistically different with or without the use of ICG-FA (OR 1.22; 95% CI 0.20–7.30; P = 0.83). The results revealed that ICG-FA reduced risks of AL, reoperation, and overall complications for colorectal cancer patients undergoing colorectal surgery. Well-designed RCTs are needed to confirm the usefulness of intraoperative ICG-FA for preventing surgical complications like AL and reoperation.

Active measurement technology is used widely in the modern precision-grinding process; currently, however, it is tedious and time consuming to adjust the process parameters of grinding process. This process usually depends on the experience of operators, which directly affects the processing efficiency and intelligent control level. Aiming to optimize these grinding-process parameters, we propose a grey target decision-making method based on the uniform effect measure to realize the intelligent optimization of process parameters. First, we obtain the experimental data of process parameters and evaluation parameters using the orthogonal experimental method, and then we calculate and analyze the degree of relation between process parameters and evaluation parameters based on grey system theory. Then we can obtain the process parameters that have the greatest influence on the workpiece surface roughness, workpiece roundness, and grinding process time. Second, through the proposed grey target decision-making method based on the uniform effect measure, and combined with grey relation analysis, we assign the weights of different evaluation parameters. By optimizing the calculation of multigroup evaluation parameters, we obtain the group of evaluation parameters with the best synthetic effect and identify the optimal combination of parameters to guide production. Through a large number of experimental verifications and analyses, we find that the proposed grinding process parameters optimization method can obtain the best combination of process parameters and can effectively improve processing quality and processing efficiency. The research results provide a theoretical basis for the optimization of grinding process parameters and enhance the intelligent degree of precision grinding.

Subarachnoid hemorrhage (SAH) is a severe subtype of stroke with high mortality. Hyperglycemia is a common phenomenon in critically ill patients and associated with poor clinical outcome. However, the predictive value of admission hyperglycemia for 30 and 90-day all-cause mortality in critically ill patients with SAH remains controversial. All SAH patients between 2001 and 2012 were included based on the MIMIC-III database and were further classified according to the tertiles of blood glucose (BG) measured on intensive care unit (ICU) admission. Clinical information including demographic data, comorbidities, and laboratory indicators were exacted and analyzed. The primary outcomes were 30- and 90-day all-cause mortality. A total of 1,298 SAH patients were included. The 30 and 90-day mortality rates were 19.80% and 22.73%, respectively. Subjects in the high glucose tertile were older, were overweight, had higher sequential organ failure assessment (SOFA) and Simplified Acute Physiology Score II (SAPS II) scores, and presented higher mortality rate. Generalized additive model revealed a U-shaped relationship between BG and 30 and 90-day all-cause mortality. Furthermore, Kaplan–Meier (K-M) survival curve also illustrated that subjects with admission hyperglycemia presented lower survival rate and shorter survival time. In Cox analysis, after adjustment for potential confounders, admission hyperglycemia was related to an increase in 30- and 90-day all-cause mortality in SAH patients. In subgroup analysis, the association between admission hyperglycemia and all-cause mortality was consistent. In conclusion, admission hyperglycemia is associated with significantly increased 30- and 90-day all-cause mortality in critically ill patients with SAH.

Efficient, accurate and reliable detection and monitoring of H2S is of significance in a wide range of areas: industrial production, medical diagnosis, environmental monitoring, and health screening. However the rapid corrosion of commercial platinum-on-carbon (Pt/C) sensing electrodes in the presence of H2S presents a fundamental challenge for fuel cell gas sensors. Herein we report a solution to the issue through the design of a sensing electrode, which is based on Pt supported on mesoporous titanium chromium nitrides (Pt/Ti0.5Cr0.5N). Its desirable characteristics are due to its high electrochemical stability and strong metal-support interactions. The Pt/Ti0.5Cr0.5N-based sensors exhibit a much smaller attenuation (1.3%) in response to H2S than Pt/C-sensor (40%), after 2 months sensing test. Furthermore, the Pt/Ti0.5Cr0.5N-based sensors exhibit negligible cross response to other interfering gases compared with hydrogen sulfide. Results of density functional theory calculation also verify the excellent long-term stability and selectivity of the gas sensor. Our work hence points to a new sensing electrode system that offers a combination of high performance and stability for fuel-cell gas sensors.

Outbreak of global pandemic Coronavirus disease 2019 (COVID-19) has so far caused countless morbidity and mortality. However, a detailed report on the impact of COVID-19 on hypertension (HTN) and ensuing cardiac injury is unknown. Herein, we have evaluated the association between HTN and cardiac injury in 388 COVID-19 (47.5 ± 15.2 years) including 75 HTN and 313 normotension. Demographic data, cardiac injury markers, other laboratory findings, and comorbidity details were collected and analyzed. Compared to patients without HTN, hypertensive-COVID-19 patients were older, exhibited higher C-reactive protein (CRP), erythrocyte sedimentation rate, and comorbidities such as diabetes, coronary heart disease, cerebrovascular disease and chronic kidney disease. Further, these hypertensive-COVID-19 patients presented more severe disease with longer hospitalization time, and a concomitant higher rate of bilateral pneumonia, electrolyte disorder, hypoproteinemia and acute respiratory distress syndrome. In addition, cardiac injury markers such as creatine kinase (CK), myoglobin, lactic dehydrogenase (LDH), and N-terminal pro brain natriuretic peptide were significantly increased in these patients. Correlation analysis revealed that systolic blood pressure correlated significantly with the levels of CK, and LDH. Further, HTN was associated with increased LDH and CK-MB in COVID- 19 after adjusting essential variables. We also noticed that patients with elevated either high sensitivity-CRP or CRP demonstrated a significant high level of LDH along with a moderate increase in CK (p = 0.07) and CK-MB (p = 0.09). Our investigation suggested that hypertensive patients presented higher risk of cardiac injury and severe disease phenotype in COVID-19, effectively control blood pressure in HTN patients might improve the prognosis of COVID-19 patients.

Background Several studies have been performed to investigate the associations between interleukin (IL)-8 rs4073 polymorphism and acute pancreatitis (AP), but the results are inconclusive. We conducted this cumulative meta-analysis for a precise estimate of the relationship between IL-8 rs4073 polymorphism and acute pancreatitis. Methods We searched the electronic databases for relevant studies. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to evaluate the strength of the associations. For a better presentation of how the pooled ORs changed as updated evidence accumulated, we used forest plots from a cumulative meta-analysis method. Results Ten studies involving 1646 AP patients and 1816 controls were finally included in this meta-analysis. Cumulative meta-analyses indicated there is a consistent trend toward association after the initial discovery. Under the allelic, dominant, recessive and homozygous models, the pooled ORs were 1.265 (1.147–1.395, p

Background:Several studies have suggested that snoring is associated with an increased risk of stroke; however, the results are inconsistent. We aim to conduct a systematic review and meta-analysis of observational studies assessing the association between snoring and the risk of stroke in adults.Methods:We searched PubMed for relevant studies. A random-effect model was adopted to summary relative risks (RRs), and forest plots from a cumulative meta-analysis method were used for a better presentation of how the pooled RRs changed as updated evidence accumulated.Results:The literature search yielded 16 articles that met our inclusion criteria, and a total of 3,598 stroke patients and 145,901 participants were finally included in our analysis. A consistent trend toward association was found after the initial discovery, and the summary analysis indicated that snoring is associated with a 46% (RR, 1.46; 95%CI, 1.29–1.63;p< 0.001) increased risk of stroke.Conclusions:Snoring is associated with a significantly increased risk for stroke, up to 46%. The importance of the current study lies in that we provide an imputes to take a more active approach against the increased risk of stroke in snorers.

BACKGROUND Laparoscopic resection for rectal cancer has been gaining popularity over the past 2 decades. Whether elderly patients had more benefits from laparoscopy-assisted anterior resection (LAR) need further investigation when comparing with open anterior resection (OAR). OBJECTIVES This study aimed to evaluate the clinical outcomes and prognosis of LAR in elderly patients (65 y and above) with rectal cancer and investigate the factors associated with the anastomotic leakage (AL). Besides, the study sought to create a nomogram for precise prediction of AL after anterior resection for rectal cancer. MATERIALS AND METHODS A total of 343 rectal cancer patients over 65 years old who underwent LAR or OAR at a single center between January 2013 to January 2021 were retrospectively reviewed. Univariate analysis was conducted to explore potential risk factors for AL, and a nomogram for AL was created based on the multivariate logistic regression model. RESULTS A total of 343 patients were included in this study, 271 patients in LAR group and 72 patients in OAR group. Most of the variables were comparable between the 2 groups. The mean operative time was longer in the LAR group than that in the OAR group (191.66±58.33 vs. 156.85±53.88 min, P

Studies have shown that blockade of CTLA-4 promoted the expansion of germinal center B-cells in viral infection or immunization with model antigens. Few studies have evaluated the immunological consequences of CTLA-4 blockade during immunization against relevant vaccine candidates. Here, we investigated the effects of CTLA-4 blockade on HIV virus-like particles (VLPs) vaccination in a C57BL/6J mouse model. We found that CTLA-4 blockade during HIV VLP immunization resulted in increased CD4+ T-cell activation, promoted the expansion of HIV envelope (Env)-specific follicular helper T cell (Tfh) cells, and significantly increased HIV Gag- and Env-specific IgG with higher avidity and antibody-dependent cellular cytotoxicity (ADCC) capabilities. Furthermore, after only a single immunization, CTLA-4 blockade accelerated T-cell dependent IgG class switching and the induction of significantly high serum levels of the B-cell survival factor, A proliferation-inducing ligand (APRIL). Although no significant increase in neutralizing antibodies was observed, increased levels of class-switched Env- and Gag-specific IgG are indicative of increased polyclonal B-cell activation, which demonstrated the ability to mediate and enhance ADCC in this study. Altogether, our findings show that CTLA-4 blockade can increase the levels of HIV antigen-specific B-cell and antigen-specific Tfh cell activity and impact humoral immune responses when combined with a clinically relevant HIV VLP-based vaccine.

Tumors are a serious threat to human health, and tumor treatments have continued to evolve from chemotherapy to targeted therapy, immunotherapy, and individualized immunotherapy. Tumor cells have many mutations that cause the production of neoantigens, which are unique to tumor cells. Tumor neoantigen vaccines can effectively activate the body’s immune system to kill tumor cells, making individualized immunotherapy based on tumor neoantigens a new direction for the development of personalized immunotherapy for tumors. This technique is unique in that it can kill cancer cells without damaging healthy tissues, it can target and attack tumors in any part of the body, it has minimal toxicity, and it is effective for almost all forms of cancer, allowing immune cells to “remember” cancer cells to prevent tumor recurrence. Tumor neoantigen vaccines are not only therapeutic but may also exert a preventive effect in high-risk groups. This therapy may also be applied to other diseases that can produce neoantigens, including infectious diseases, which increases the potential for broad application.

Developers spend a great deal of time to adapt UI to different devices. By learning experience from massive number of human designed UI products, the adaptation work could be finished by machines. To this end, we introduce DUES-Adapt, an AI based UI adaptation system, and showcase in this demonstration. Given an input UI, DUES-Adapt parses the basic UI elements and employs the parsing results to generate a reasonable and aesthetic layout for a target device. The two AI problems, UI parsing and layout generation, are solved using deep neural network model and trained with over 10K app instances collected from mainstream Android markets. In the demonstration, we show a number of cases covering many apps like music, maps, fitness and different target terminals such as tablet, smartwatch, TV etc.

Digital receivers are a main subject that forms modern radio astronomical technology. Because of advancements in analog-to digital converters (ADCs) and increases in digital signal processing capacity, massive amounts of astronomical data can be processed fast enough to match the scientific observation requirements. So, in this chapter, we will introduce the core processing procedures in digital receivers to bridge analog RF to science processing data: digitization, channelization, and packeting. Many other arithmetic operations can also be applied between or after these core procedures such as pulsar timing, dedispersion, beamforming, correlation, etc., which will be discussed in further chapters.

Food adulteration is a growing concern worldwide. The collation and analysis of food adulteration cases is of immense significance for food safety regulation and research. We collected 961 cases of food adulteration between 1998 and 2019 from the literature reports and announcements released by the Chinese government. Critical molecules were manually annotated in food adulteration substances as determined by food chemists, to build the first food adulteration database in China (http://www.rxnfinder.org/FADB-China/). This database is also the first molecular-level food adulteration database worldwide. Additionally, we herein propose an in silico method for predicting potentially illegal food additives on the basis of molecular fingerprints and similarity algorithms. Using this algorithm, we predict 1919 chemicals that may be illegally added to food; these predictions can effectively assist in the discovery and prevention of emerging food adulteration.

Background Most coronary spastic angina patients are responsive to coronary vasodilators therapy, and stent implantation is not recommended for regular use. We reported the angiographic and intravascular ultrasound (IVUS) images of a rare case who responded poorly to medical treatment due to progressive atherosclerotic plaque at the spastic site. Case presentation A 60-year-old man complaining of 1-month history of episodic chest pain at rest was admitted to our hospital. The diagnosis of coronary spastic angina was made based on the angiographic evidence of vasospasm at the right coronary artery (RCA). The patient responded poorly to conventional medical treatment during the 1-year follow-up. The repeated angiography revealed totally occlusion of the proximal segment of the RCA at the same location as 1 year before, and IVUS demonstrated there was vulnerable plaque and thrombus at the site of spasm. Episodic chest pain ceased completely in the follow up period after stenting. Conclusion Coronary spasm might present at the vessel site with advanced atherosclerotic plaque. For patients with refractory vasospastic angina and significant occlusion, stenting might be a viable and valuable treatment strategy under the guidance of intracoronary imaging.

Background and purpose To develop and validate a risk model (Extracranial Carotid Artery Stenosis score, ECAS score) to predict moderate and severe ECAS. Furthermore, we compared discrimination of the ECAS score and three existing models with regard to both moderate and severe ECAS. Methods The ECAS score was developed based on the Renqiu Stroke Screening Study (RSSS), in which eligible patients were randomly divided into derivation (60%) and validation (40%) cohorts. ECAS was diagnosed by carotid duplex ultrasound according to the published criteria. Independent predictors of moderate (≥50%) and severe (≥70%) ECAS were obtained using multivariable logistic regression. The area under the receiver operating characteristic curve (AUROC) and the Hosmer-Lemeshow test were used to assess model discrimination and calibration. Results A total of 5010 participants were included and the mean age was 64.3. The proportion of ECAS of 50%, 50-69%, 70-99% and occlusion was 4.4, 0.5, 0.4, and 0.4%, respectively. The ECAS score was developed from sets of predictors of moderate and severe ECAS. The ECAS score demonstrated good discrimination in the derivation and validation cohorts (AUROC range: 0.785-0.846). The Hosmer-Lemeshow tests of ECAS score for moderate and severe ECAS were not significant in the derivation and validation cohorts (all P 0.05). When compared to the three existing models, the ECAS score showed significantly better discrimination for both moderate and severe ECAS (all P 0.001). Conclusion The ECAS score is a valid model for predicting moderate and severe ECAS. Further validation of the ECAS score in different populations and larger samples is warranted.

Development of a vaccine that can elicit robust HIV specific antibody responses in the mucosal compartments is desired for effective prevention of HIV via sexual transmission. However, the current mucosal vaccines have either poor immunogenicity when administered orally or invite safety concerns when administered intranasally. Sublingual immunization has received more attention in recent years based on its efficiency in inducing systemic and mucosal immune responses in both mucosal and extra-mucosal tissues. To facilitate the transport of the immunogen across the sub-mucosal epithelial barrier, we found that CD91, the receptor of C1q, is prevalently expressed in the sublingual mucosal lining, and thus, a modified chimeric C1q surface conjugated CD40L/HIV VLP was generated. The ability of this chimeric C1q/CD40L/HIV VLP to bind, cross the epithelial layer, access and activate the sub-mucosal layer dendritic cells (DCs), and ultimately induce enhanced mucosal and systemic immune responses against HIV is evaluated in this study. We found that C1q/CD40L/HIV VLPs have enhanced binding, increased transport across the epithelial layer, and upregulate DC activation markers as compared to CD40L/HIV VLPs alone. Mice immunized with C1q/CD40L/HIV VLPs by sublingual administration showed higher levels of IgA salivary antibodies against both HIV Gag and Env than mice immunized with CD40L/HIV VLPs. Moreover, sublingual immunization with C1q/CD40L/HIV VLPs induced more Env- and Gag-specific IFN-γ producing T cells than the CD40L/HIV VLPs group. Interestingly, C1q/CD40L/HIV VLP immunization can also induce more mucosal homing T cells than that in CD40L/HIV VLP group. Our data suggest that incorporation of C1q to CD40L/HIV VLPs is a promising novel strategy and that the sublingual immunization can be a favorite immunization route for HIV mucosal vaccines.

The presence of natural toxins, pesticide residues, and illegal additives in food products has been associated with a range of potential health hazards. However, no systematic database exists that comprehensively includes and integrates all research information on these compounds, and valuable information remains scattered across numerous databases and extensive literature reports. Thus, using natural language processing technology, we curated 12,018 food risk components from 152,737 literature reports, 12 authoritative databases, and numerous related regulatory documents. Data on molecular structures, physicochemical properties, chemical taxonomy, absorption, distribution, metabolism, excretion, toxicity properties, and physiological targets within the human body were integrated to afford the comprehensive food risk component database (FRCD, http://www.rxnfinder.org/frcd/). We also analyzed the molecular scaffold and chemical diversity, in addition to evaluating the toxicity and biodegradability of the food risk components. The FRCD could be considered a highly promising tool for future food safety studies.

Background and purpose: To develop and validate a risk model (Extracranial Carotid Artery Stenosis progression score, ECAS-PS) and to predict risk of ECAS progression. Methods: The ECAS-PS was developed based on the Renqiu Stroke Screening Study (RSSS), in which eligible participants were randomly divided into derivation (60%) and validation (40%) cohorts. ECAS at baseline and follow-up was diagosed by carotid duplex ultrasound according to the published criteria. ECAS progression was defined as an increase in ECAS to≥50% for those with a baseline of Results: A total of 4111 participants were included and the mean age was 64.3. A total number of 29 (0.7%), 24 (0.6%) and 48 (1.2%) patients progressed during 2-year follow-up for left, right and bilateral (either left or right) carotid artery, respectively. The ECAS-PS was developed from a set of predictors of ECAS progression. The ECAS-PS demonstrated good discrimination in both the derivation and validation cohorts (AUROC range: 0.824–0.917). The Hosmer–Lemeshow tests of ECAS progression score were not significant in the derivation and validation cohorts (all P > 0.05). Conclusion: The ECAS progression score is a valid model for predicting the risk of ECAS progression. Further validation of the ECAS-PS in different populations and larger samples is warranted.

A geometric error determines the quality and function of a product to a certain extent. Cylindricity error is an important indicator of the geometric error of form parts. In recent years, with the development of geometric product verification and specification (GPS), the specification of the cylindricity error and high-precision detection have become the focus in the field of industrial metrology. In this paper, by analyzing the existing cylindricity evaluation strategy, a new method for cylindricity error evaluation based on increment-simplex algorithm is proposed. The purpose is to improve the efficiency of cylindricity error analysis on the basis of ensuring the accuracy requirements. First, according to the GPS specification, the characteristics and applications of the circular section method, the helicoid line method, the generatrix line method, and the bird-cage method for the extraction operation are analyzed. And for the fitting operation, the mathematical models of the cylindricity fitting for the least squares cylinder, minimum circumscribed cylinder, maximum inscribed cylinder, and minimum zone cylinder in cartesian and cylindrical coordinate systems are constructed. Second, a new method of cylindricity error optimization evaluation based on the incremental optimization method is proposed. A theoretical analysis of the new method is made with the circular section method as an example, and the specific steps of cylindricity error analysis based on the circular section method of the new method are given. Finally, experiments and analysis are carried out, and the accuracies and evaluation efficiencies of the cylindricity error of the different cylindricity measurement and evaluation strategies are compared and analyzed. The results and operating efficiency of the increment-simplex algorithm and the traditional algorithms are compared, and the effectiveness and feasibility of the new method are proved.

Large deformation control of soft rock roadway is a major challenge for the safety of mining production. Herein, a well-documented case study of a soft rock roadway is presented regarding its large deformation mechanism and the corresponding control technology. The failure characteristics of the studied roadway under the original support scheme were analyzed in detail, and the large deformation mechanism was discussed combining the geological conditions, rock mass properties and the original support scheme. A reasonable numerical method for concrete-filled steel tubular (CFST) support was proposed, and the bearing performance of the inclined-wall arc arch CFST support was analyzed. Then, a modified combined support scheme composed of ‘bolt-cable + mesh + shotcrete’ and CFST support was proposed and validated by numerical analysis and field application. The results show that there are three main reasons resulting in the large deformation of the background roadway, which are: the contradiction between high in situ stress and broken surrounding rock, the contradiction between high clay mineral composition and poor disintegration resistance, and unreasonable original support scheme with low bearing capacity. The monitoring data obtained from both numerical analysis and field application show that the modified combined support scheme was effective for controlling the large deformation of the studied roadway. This work can provide some helpful guidance for similar projects.

In recent years, the applications of Aerial UAV are more and more extensive. The aerial system is subject to the impact of the relative movement, posture changes and the atmosphere, which results in low clarity of the captured image. Based on the image blur phenomenon caused by UAV flight, a function is introduced as its coefficient in Lucy-Richardson (LR) image restoration algorithm, which could effectively protect edge details of the image. The results of image quality evaluation show that the improved LR algorithm can effectively suppress the noise in the image and improve the clarity of the image.

Comparative studies on several direct torque control (DTC) strategies of interior permanent magnet synchronous motor (IPMSM) for electric vehicles (EVs) are discussed in details, namely basic DTC, DTC combined with space vector modulation (DTC-SVM), and deadbeat DTC (DB-DTC). These DTC strategies are reviewed, meanwhile dynamics and steady-state performance are analyzed and compared. Simulations of a 20kW IPMSM for EVs are carried out for comparison studies including: ripple of torque and stator flux, sensitivity to machine's parameter, computational complexity, and total harmonic distortion of stator current. The results can be used as guidance for application of IPMSM to EVs and others.

Background Several studies have suggested that cytomegalovirus infection is likely associated with an increased relative risk of cardiovascular disease ( CVD ); however, the results are inconsistent. We aimed to provide a systematic review and meta‐analysis of community‐based prospective studies assessing the association between cytomegalovirus infection and relative risk of CVD . Methods and Results We searched Medline and EMBASE to retrieve prospective studies that reported risk estimates of the association between cytomegalovirus infection and relative risk of CVD . The search yielded 10 articles including a total of 34 564 participants and 4789 CVD patients. Overall, exposure to cytomegalovirus infection was associated with a 22% (relative risk: 1.22, 95% CI : 1.07–1.38, P =0.002) increased relative risk of future CVD . We estimated that 13.4% of CVD incidence could be attributable to cytomegalovirus infection. Conclusions In conclusion, cytomegalovirus infection is associated with a significantly increased relative risk of CVD .

In order to optimize the ventilation effect of ammonia leakage in the refrigeration machinery room, a food processing enterprise is selected as the subject investigated. The velocity and concentration field distribution during the process of ammonia leakage are discussed through simulation of refrigeration machinery room using CFD software. The ventilation system of the room is optimized in three aspects which are named air distribution, ventilation volume and discharge outlet. The influence of the ammonia alarm system through ventilation is also analyzed. The results show that it will be better to set the discharge outlet at the top of the plant than at the side of the wall, and the smaller of the distance between the air outlet and the ammonia gathering area, the better of the effect of ventilation will be. The air flow can be improved and the vortex flow can be reduced if the ventilation volume, the number of air vents and the exhaust velocity are reasonably arranged. Not only the function of the alarm could be ensured, but also the scope of the detection area could be enlarged if the detectors are set on the ceiling of the refrigeration units or the ammonia storage vessel.

Heavy-equipment airdrop is a highly risky procedure that has a complicated system due to the secluded and complex nature of factors’ coupling. As a result, it is difficult to study the modeling and safety simulation of this system. The dynamic model of the heavy-equipment airdrop is based on the Lagrange analytical mechanics, which has all the degrees of freedom and can accurately pinpoint the real-time coordinates and attitude of the carrier with its cargo. Unfavorable conditions accounted in the factors’ models, including aircraft malfunctions and adverse environments, are established from a man-machine-environment perspective. Subsequently, a virtual simulation system for the safety research of the multi-factor coupling heavy-equipment airdrop is developed through MATLAB/Simulink, C language and Flightgear software. To verify the veracity of the theory, the verification model is built based on dynamic software ADAMS. Finally, the emulation is put to the test with the input of realistic accident variables to ascertain its feasibility and validity of this method.

A series of tunable filters based on silicon nitride waveguide Bragg gratings buried in polymer are studied, fabricated and analyzed. The gratings are etched completely through the waveguides to improve the peak reflectivity at short grating lengths. Reflectivity from 1% to 70% can be reached when the third-order grating length varies from 16 µm to 160 µm. The experimental results are in good agreement with numerical simulations. Due to its compact size and the thermal advantages of polymer, the filter can be tuned very efficiently by a micro heater buried beneath. A tuning range of 34.5 nm is demonstrated at a heat power of only 22 mW.

Confined space is a special working place. To ensure the safety, the forced ventilation must be carried out before entering the confined space. In this paper, ventilation process in municipal heating confine space is simulated by CFD numerical simulation method, and the distribution of temperature, oxygen and carbon dioxide in municipal heating confined space during ventilation process is studied. The simulation results show that the airflow and temperature are obviously stratified in vertical direction during the ventilation. The temperature is low and the airflow velocity is high at the bottom part of the tunnel. While the temperature is high and the airflow velocity is low at the top of the tunnel. By contrast, recovery of the oxygen and carbon dioxide content is relatively faster at the bottom than it at the top. When the ventilation volume flow rates are 6000 m3·h−1, 8000 m3·h−1, 10000 m3·h−1, 12000 m3·h−1, and 14000 m3·h−1 respectively, the time when the temperature reach stable and gas fraction return to normal are 45 minutes, 32 minutes, 22 minutes, 15 minutes, 10 minutes respectively.

Previous observational studies have suggested a potential relationship between osteoarthritis (OA) and the risk of cardiovascular disease (CVD), with conflicting results. We aimed to provide a systematic and quantitative summary of the association between OA and the risk of CVD. We searched Medline and EMBASE to retrieve prospective and retrospective studies that reported risk estimates of the association between OA status and CVD risk. Pooled estimates were calculated by a random effects model. The search yielded 15 articles including a total of 358,944 participants, including 80,911 OA patients and 29,213 CVD patients. Overall, the risk of CVD was significantly increased by 24% (RR: 1.24, 95% CI: 1.12 to 1.37, P

In any grinding process, compensation regulation value is a crucial factor for maintaining precision during the batch processing of workpieces. Geometric characteristics, buffing allowance, temperature, wheel speed, and workpiece speed are the main factors that affect compensation regulation value in any grinding process. In this article, a novel prediction method for compensation regulation value is proposed based on incremental support vector machine and mixed kernel function. The support vectors for the prediction model are extracted using the convex hull vertex optimization algorithm, and the speed of the operation can be increased effectively. In addition, the parameters of the model are optimized using cross-validation optimization method to improve the accuracy of the prediction model. Then, the feedback control strategy of compensation regulation value for the grinding process is also proposed. Single-factor and multi-factor experiments are implemented respectively using the proposed method. The results verify the feasibility and effectiveness of the proposed method. It is also noted that the machining accuracy is improved significantly in comparison with the machining without prediction and compensation control. Moreover, by applying the prediction compensation control of compensation regulation value to the active measurement and control of the grinding process, a feedback system is formed, and then the intelligentization of the grinding system can be realized.

This paper has presented the control strategy of Space Vector Pulse Width Modulation in over-modulation range by contrast. Based on the three-level inverter vector control theory, the cause of over-modulation generated is explained. Several typical over-modulation control strategies are summarized in detail, such as typical dual-mode strategy, typical single-mode strategy, the minimum phase angle error strategy and the minimum amplitude error strategy. Over-modulation algorithm can improve effectively output fundamental voltage, shorten the motor dynamic response time, and expand steady-state operating region. But some problems included harmonic current issue and DC bus voltage instability are pointed out. To deal with these problems, the improved over-modulation algorithms have an effective influence on accurate control of system.

A study is conducted on a new airworthiness compliance verification method based on pilot-aircraft-environment complex system simulation. Verification scenarios are established by “block diagram” method based on airworthiness criteria. A pilot-aircraft-environment complex model is set up and a virtual flight testing method based on connection of MATLAB/Simulink and Flightgear is proposed. Special researches are conducted on the modeling of pilot manipulation stochastic parameters and manipulation in critical situation. Unfavorable flight factors of certain scenario are analyzed, and reliability modeling of important system is researched. A distribution function of small probability event and the theory on risk probability measurement are studied. Nonlinear function is used to depict the relationship between the cumulative probability and the extremum of the critical parameter. A synthetic evaluation model is set up, modified genetic algorithm (MGA) is applied to ascertaining the distribution parameter in the model, and a more reasonable result is obtained. A clause about vehicle control functions (VCFs) verification in MIL-HDBK-516B is selected as an example to validate the practicability of the method.

Field-oriented control of permanent magnet synchronous motor fed by matrix converter is designed. By introducing space vector modulation for inverter, AC-AC matrix converter is equivalent to AC-DC-AC substitution. Then, perfect PWM technology is adopted for virtual rectifier and virtual inverter of substitution whose modulating schedule and model are analyzed and deduced. of field-oriented control for matrix converter fed permanent magnet synchronous motor is built up. Finally, simulations are carried out, and simulating results show that the proposed system is feasible and valid, which provides theoretical foundations for experimentation.

The existence of high-frequency components in common-mode (CM) current would reduce the stability of a non-isolated PV grid-connected system. It has great impacts on the output power quality when the generated power from PV is low. The method of single CM inner loop in suppressing the high-frequency components has poor effect. Based on the CM equivalent circuit model and the cause analysis of the CM current, a novel dual CM inner loops method is proposed to restrain the high-frequency components in CM current. This method not only meets the grid connection demand of CM current, but also overcomes the high frequency resonant problem. Furthermore, the high-frequency components in CM current from the outer parasitic circuit are substantially reduced. Finally, the proposed method is verified by simulation and experimental results.

Sampled gratings based on low-loss buried silicon nitride waveguides in polymer have been fabricated and investigated. Low-temperature plasma enhanced chemical vapor deposition and standard photolithography are used to form the silicon nitride core layer directly on polymer. These gratings show a common peak interval of 7.3 nm but varying 3-dB mode numbers according to the design. Since the optical mode expands largely into the cladding, the thermo-optic effect of the polymer material dominates. With buried heating electrodes, wavelength tuning of 8.1 nm has been achieved at ~ 100 mW of electrical heating power.

Current aircraft on-site maintenance management has many deficiencies. A new intelligent automation system based on ZigBee wireless network to ameliorate current aircraft on-site maintenance management is proposed. System structure and advantages of ZigBee wireless network is introduced. Application possibility of ZigBee technology to aircraft on-site maintenance management is analyzed. Improved workflow of aircraft on-site maintenance management based on automation system is established. Personnel and equipment scheduling based on ZigBee wireless network is put forward. Aircraft status information access and dissemination method is studied. On-site maintenance data storage and analysis method is researched. System architecture and implementation method is analyzed.

In this paper, we employ the big data method to structural analysis by considering the correlations between loads and loads, loads and results and results and results. By means of fundamental mathematics and physical rules, the principle, feasibility and error control of the method are discussed. We then establish the analysis process and procedures. The method is validated by two examples. The results show that the fast simulation method based on big data is fast and precise when it is applied to structural analysis.

Recent progress of low-loss silicon nitride waveguide in polymer is presented. The fabrication technology requires only low temperature (

Morris Water Maze (MWM) is a device in which rats learn to escape from opaque water onto a hidden platform. It is widely used in brain function evaluation, such as the ability of study, fatigue property test and resistance experiment. The ability is evaluated by the time and the distance rats spent in finding the hidden platform. An image collection simulation system was designed with a digital camera, a computer and an image acquisition (IMAQ) card based on virtual instrument, and the swimming trace of the experimental animal was captured into the computer and can be analyzed in real time. In addition, the system consists of the image capture, display and save, parameters setting, image identify and trace display module, data analysis in real time and redisplay mode. And the system has the open characteristics, so new modules can be added and functions can be expanded according to varies needs in the future. Also, vibration is creatively used as a parameter to evaluate the rat's memory in this system, and the dynamic pie chart quadrant is used to describe the time that the rat move.

Vector control of permanent magnet synchronous motor (PMSM) using modified current hysteresis control based on matrix converter (MC) is discussed. In order to improve utiLization of input voltage resources, input voltages are divided into 12 sections within one periond. A modified current controller composed of two nested current hysteresis control is analyzed in details. According to outputs of current controller and section of input voltages, a proper input voltage sHould be selected to encrease or decrease output current of matrix converter. The selection table is analyzed and partially deduced. Finally, simulation system is built up. Simulating results show that vector control of PMSM with modified current controller based on matrix converver has the quaLity of feasibiLity and efficiency, which brings out theoretical foundations of experimentation.

To meet the needs of design and analysis for special ultrasound transducer and complex multi-parameters array of ultrasonic transducers, a robotic system was developed to measure and analyze the feature of complex ultrasound field. The system integrated with mechanical robot, electronic control, hydrophone and measurement and analysis software modules. The system can automatically scan the whole field in any direction and locate at any point with high spatial resolution, precise (0.05 mm) and good frequency response to overcome the problems of measurement, analysis and modeling for complex ultrasound transducer. A standard focused ultrasound field was used to verify accuracy of the measuring system, and modeling results of measured data was consistent with ultrasonic theory model. The results indicated that the auto-measuring system and analysis model have good veracity to analyze and model complex ultrasound field, and provides an effective way to evaluate the design of complex and special ultrasonic transducer. It can also be used to study biological effects with feature of special ultrasound field in clinical application and to assess real treatment effect in animal treating experiment with automatically measuring and analysis. The system also can apply to evaluate the field produced by any kind of shockwave.

Besides the severe ground shaking, fires induced by earthquakes are usually the major causes of human casualties and properties losses. This paper presents a newly developed intelligent system, which can prevent ignition of fires and promptly report fires following earthquakes. The system consists of three key components: (1) a remote-controlled off/on valve for gas pipes to prevent the ignition of fires following earthquakes, (2) a cell-phone based wireless information unit to promptly report the fires if fires do occur, and (3) a central signal processing unit to analyze the fire data transferred and send the commands such as shut-off/reset-on of the valves through the wireless information unit.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Optical waveguides have been fabricated and investigated that employ silicon nitride as core and polymer as surrounding cladding material. Buried single-mode waveguides showed a propagation loss of ∼0.7 dB/cm at 1550 nm. Depending on the thickness of the silicon nitride core, the optical mode can be designed to expand largely into the polymer cladding. Using such a low-confinement structure and a metal strip heater embedded in the polymer cladding material beneath the core region, efficient thermally tunable waveguide Bragg grating filters were demonstrated. Wavelength tuning >57 nm was achieved at ∼220 mW of electrical heating power.