Five-Year Longitudinal Assessment of the Downstream Impact on Schistosomiasis Transmission following Closure of the Three Gorges Dam

Schistosomiasis, caused by Schistosoma japonicum, is a significant parasitic disease and public health problem in China. How the parasite is transmitted there can be categorized into four distinct modes (modes I–IV) and it is predicted that the Three Gorges Dam, recently completed, will affect the way schistosomiasis is spread in these modes. We monitored transmission for a 5-year period (2002–2006) in eight villages, representative of the three modes (I–III) below the dam across four provinces (Hunan, Jiangxi, Hubei and Anhui) to determine whether there was any immediate impact of the dam on schistosomiasis spread. Human schistosomiasis incidence declined considerably within individual villages and each mode, and the yearly odds ratios (adjusted) for infection risk showed significant downward trends in all three modes over the follow-up period. The decreased human S. japonicum incidence recorded across transmission modes I–III was probably attributable to annual human and bovine praziquantel drug treatment. If an increase in schistosome transmission had occurred as a result of the dam, it would be of negligible size compared with this treatment-induced decline. There had thus been virtually no immediate impact of the TGD on schistosomiasis transmission downstream of the dam over the 5-year surveillance period

Coupled Superhydrophilic PMMA Film with Inverted Pyramid Microstructures for Antireflection and Antifogging Properties

Transparent substrates with antifogging and antireflection ability are of extreme significance for optical devices, because they alleviate performance loss and maintenance costs. Here, we reported that a multifunctional film, with excellent mechanical properties, can be fabricated on the PMMA surface via the micro-transfer printing method. In particular, the synergistic effect of the inverted pyramid microstructure and SiO2 nanoparticles gives the film excellent antireflective, superhydrophilic and antifogging properties, and the silica sol firmly adheres to the PMMA substrate via the silane coupling agent, which exhibits an encouraging prospect of practical applications from lenses for personal and sports eyewear to transparent displays and sensors, etc

Preparation and Evaluation of PDMS/Carbon Soot Particles Superhydrophobic Biomimetic Composite Coating with Self-Cleaning and Durability

In this paper, a superhydrophobic biomimetic composite coating was fabricated on brass by electrochemical etching, brushing PDMS adhesive layer, and depositing carbon soot particles. Due to the microstructure and the optimized ratio of PDMS, the contact angle of the superhydrophobic coating is up to 164° and the sliding angle is only 5°. The results of optical microscopy and morphometric laser confocal microscopy show that the prepared coating surface has a rough hierarchical structure. A high-speed digital camera recorded the droplet bouncing process on the surface of the superhydrophobic coating. The self-cleaning property of the coatings was evaluated by applying chalk dust particles as simulated solid contaminants and different kinds of liquids (including grape juice, beer, cola, and blue ink) as liquid contaminants. The coating remained superhydrophobic after physical and chemical damage tests. This work presents a strategy for fabricating superhydrophobic biomimetic composite coatings with significant self-cleaning properties, durability, and shows great potential for practical engineering applications

Research on High Speed Cutting Parameter Optimization and Fault Diagnosis Technology

High speed cutting process is a very complicated process; cutting parameters have a significant effect on cutting process and play a key role in the process of product manufacturing. The overall scheme of high speed cutting parameter optimization and its fault diagnosis have been introduced. The mathematical model of the selected cutting parameters was established and the optimized parameters were obtained by combining the experimental design with the technology of data processing. The statistical description of high speed cutting process control was introduced and the fault diagnosis model of cutting parameter optimization by using the neural network was proposed. Finally, the mathematical model in the present study is validated with a numerical example. The results show that the present method solved the problem of poor universality of high speed cutting data effectively and avoided the inaccuracy of physical and chemical mechanism research. Meanwhile, the present study prevents the passive checks of the cutting and gets better diagnosis of the complicated cutting fault type

Related factors of outcomes of pharyngeal foreign bodies in children

Objective: This study aimed to identify factors related to outcomes of the pharyngeal foreign bodies in children and to improve the management protocol of this disease. Methods: The medical records of 131 children with pharyngeal foreign bodies hospitalized in the hospital were retrospectively reviewed. Results: Significant differences were observed between the two groups (dislodgement and removal group) with respect to location of pharyngeal foreign bodies and age, while sex, time of pharyngeal foreign bodies, and nature of pharyngeal foreign bodies had no significant differences. Moreover, results suggested that location of pharyngeal foreign bodies and nature of pharyngeal foreign bodies were risk factors correlated with complications. Conclusion: Pharyngeal foreign body in children has a high rate of dislodgement (>50%). Foreign bodies in the oropharynx were more likely to dislodge compared with the foreign bodies in the laryngopharynx. Younger children were more likely to dislodge compared with older children. Although the risk of complications was very low, attention needs to be paid to the potential risks: local infection, deep abscess, and migration of foreign bodies. Because the possibility of complications caused by bone fragments and foreign bodies in the laryngopharynx increase obviously, hence, it is suggested to remove these kinds of foreign bodies as soon as possible to prevent complications

Research progress of vitrified bond CBN grinding wheel

The ceramic CBN grinding wheels are widely used in the fields of forming and precision machining, and the research on them is of great significance in improving the machining quality and efficiency of workpieces. The research progress of ceramic CBN grinding wheels in recent years is summarized from various aspects, including CBN abrasive grains, modifier addition, preparation and grinding performances. Additionally, the future development prospects are also discussed. Regarding CBN abrasive grains, the synthesis of CBN single crystal is explored, and the surface treatment of CBN abrasive grains, as well as the treatment methods when adding a strong magnetic field, are introduced. Concerning modifier, the influences of adding pore forming agents, oxides, metal materials and nano-materials on the performances of ceramic CBN grinding wheels are discussed. In the preparation of ceramic CBN grinding wheels, the methods of forming and sintering are described. Moreover, the grinding applications of ceramic CBN grinding wheels on difficult-to-machine materials such as steel, nickel base alloy and titanium alloy are introduced, and the factors affecting the grinding performances of CBN grinding wheels are proposed

Compressive Strength Prediction of High-Strength Concrete Using Long Short-Term Memory and Machine Learning Algorithms

Compressive strength is an important mechanical property of high-strength concrete (HSC), but testing methods are usually uneconomical, time-consuming, and labor-intensive. To this end, in this paper, a long short-term memory (LSTM) model was proposed to predict the HSC compressive strength using 324 data sets with five input independent variables, namely water, cement, fine aggregate, coarse aggregate, and superplasticizer. The prediction results were compared with those of the conventional support vector regression (SVR) model using four metrics, root mean square error (RMSE), mean absolute error (MAE), mean absolute percentage error (MAPE), and correlation coefficient (R2). The results showed that the prediction accuracy and reliability of LSTM were higher with R2 = 0.997, RMSE = 0.508, MAE = 0.08, and MAPE = 0.653 compared to the evaluation metrics R2 = 0.973, RMSE = 1.595, MAE = 0.312, MAPE = 2.469 of the SVR model. The LSTM model is recommended for the pre-estimation of HSC compressive strength under a given mix ratio before the laboratory compression test. Additionally, the Shapley additive explanations (SHAP)-based approach was performed to analyze the relative importance and contribution of the input variables to the output compressive strength

Study on Preparation and Grinding Performance of Vitrified Bond CBN Grinding Wheel with Controllable Porosity

Vitrified bond cubic boron nitride (CBN) grinding wheel specimens with controllable porosity were prepared by regulating the pore former dextrin content and varying the forming pressure, and the performance of the grinding camshaft was studied. The porosity of the specimens increases with the increase in dextrin content, and decreases first and then increases with the increase in the forming pressure. The grinding experiments show that the dextrin content is negatively correlated with the grinding force and grinding temperature, while the grinding force and grinding temperature of the specimens increase and then decrease with the increase in the forming pressure. When we observe and measure the grinding surface of the specimen and workpiece, we see that the surface roughness of the specimen after grinding is smaller than that before grinding. In addition, the greater the porosity of the specimen, the rougher the surface of the workpiece after grinding