Preparation and Properties of Corn Starch/Chitin Composite Films Cross-Linked by Maleic Anhydride

To improve the functional properties of starch-based films, chitin (CH) was prepared from shrimp shell powder and incorporated into corn starch (CS) matrix. Before blending, maleic anhydride (MA) was introduced as a cross-linker. Composite CS/MA-CH films were obtained by casting-evaporation approach. Mechanical property estimation showed that addition of 0–7 wt % MA-CH improved the tensile strength of starch films from 3.89 MPa to 9.32 MPa. Elongation at break of the films decreased with the addition of MA-CH, but the decrease was obviously reduced than previous studies. Morphology analysis revealed that MA-CH homogeneously dispersed in starch matrix and no cracks were found in the CS/MA-CH films. Incorporation of MA-CH decreased the water vapor permeability of starch films. The water uptake of the films was reduced when the dosage of MA-CH was below 5 wt %. Water contact angles of the starch films increased from 22° to 86° with 9 wt % MA-CH incorporation. Besides, the composite films showed better inhibition effect against Escherichia coli and Staphylococcus aureus than pure starch films

Polyvinyl Alcohol Microspheres Reinforced Thermoplastic Starch Composites

We reported a new method to prepare polyvinyl alcohol (PVA)/thermoplastic starch (TPS) composites by using polyvinyl alcohol microspheres (PVAMS). The PVAMS/TPS composites were characterized using tensile test, scanning electron microscopy (SEM), dynamic mechanical thermal analysis (DMTA) and thermogravimetric analysis (TGA). The results exhibited that adding small amounts of PVAMSs can effectively improve the mechanical strength and toughness of the composites, especially for the 1 wt %PVAMS in TPS matrix, with a tensile strength of 3.5 MPa, an elongation at break at 71.73% and an impact strength of 33.4 kJ/m2. Furthermore, the SEM and shift in the tan δ peak (Tα and Tβ) at the maximum value of 69.87 and −36.52 °C indicates that the PVAMS decreased the mobility of the amorphous starch molecules due to the strong intermolecular hydrogen bonds between PVAMS and TPS. The peak temperature of maximum decomposition rate (Tp) of 1 wt % PVAMS/TPS composites increased about 5 °C compared with TPS in TGA curves

Ontology construction and safety rule reasoning of main types of work in coal mine

At present, the ontology of coal mine field focuses on the prediction of accidents, and there is no ontology research for the operation safety of coal mine operating personnel. In order to detect the dangerous operation of operating personnel in time to provide safety warning for operating personnel, a method of ontology construction and safety rule reasoning for main types of work in coal mine is proposed. According to the actual production situation of coal mine, the information of operating personnel, apparatus, operating methods, location, environment, accidents and state in coal mine production is formally represented. The main types of work ontology of coal mine covering coal mining system, roadway heading system, electromechanical transportation, geological survey, ventilation gas, comprehensive dust prevention, coal preparation plant and other production systems is constructed by ontology language. According to the safety production regulations in the professional literature of coal mine field, the safety rules are formulated based on Jena custom rule grammar, and the reasoning of operation safety of operating personnel in the main types of work ontology of coal mine is realized based on the safety rules. The experimental results show that it is effective and feasible to judge the safety state of operating personnel based on the ontology of main types of work and safety rules, which provides an auxiliary guarantee method for coal mine safety production

Bio-Based Thermoplastic Starch Composites Reinforced by Dialdehyde Lignocellulose

In order to improve the mechanical properties and water resistance of thermoplastic starch (TPS), a novel reinforcement of dialdehyde lignocellulose (DLC) was prepared via the oxidation of lignocellulose (LC) using sodium periodate. Then, the DLC-reinforced TPS composites were prepared by an extrusion and injection process using glycerol as a plasticizer. The DLC and LC were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and the effects of DLC content on the properties of the DLC/TPS composites were investigated via the evaluation of SEM images, mechanical properties, thermal stability, and contact angles. XRD showed that the crystallinity of the DLC decreased due to oxidation damage to the LC. SEM showed good dispersion of the DLC in the continuous TPS phase at low amounts of DLC, which related to good mechanical properties. The tensile strength of the DLC/TPS composite reached a maximum at a DLC content of 3 wt.%, while the elongation at break of the DLC/TPS composites increased with increasing DLC content. The DLC/TPS composites had better thermal stability than the neat TPS. As the DLC content increased, the water resistance first increased, then decreased. The highest tensile strength and elongation at break reached 5.26 MPa and 111.25%, respectively, and the highest contact angle was about 90.7°

DataSharing_Dryad

Data from: One-shot dilation versus serial dilation technique for access in percutaneous nephrolithotomy: a systematic review and meta-analysis

Data from: One-shot dilation versus serial dilation technique for access in percutaneous nephrolithotomy: a systematic review and meta-analysis

Objective: The purpose of this study was to systematically review the outcomes of the use of one-shot dilation (OSD) and serial tract dilation for percutaneous nephrolithotomy (PCNL). Methods: A systematic review and meta-analysis was conducted. The randomized controlled trials (RCTs) included in the study were identified from EMBASE, MEDLINE, and the Cochrane Central Register of Controlled Trials. The last search was performed on April 30, 2018. Summary effects were calculated as risk ratios (RRs) with 95% confidence intervals (CIs) or mean differences (MDs) with 95% CIs. The endpoints included access time, fluoroscopy time, successful dilation rate, stone-free rate, postoperative decrease in hemoglobin levels, transfusion rate, complication rate, and length of postoperative hospital stay. Results: A total of 7 RCTs were included in the study, with clinical data reported for 697 patients. The overall access time was approximately 110 seconds shorter in the OSD group than in the serial dilation group (MD, -110.14; 95% CI, -161.99 to -58.30; P<0.0001). The fluoroscopy time was shorter with OSD in all RCTs. In addition, the decrease in postoperative hemoglobin levels was approximately 0.23 g/dl less in patients in the OSD group than in those in the serial dilation group (MD, -0.23; 95% CI, -0.39 to -0.07; P=0.004). No relationship was found between the successful dilation rate, stone-free rate, transfusion rate, or complication rate and the method of tract dilation. Conclusion: OSD is a safe and efficacious tract dilation technique that can reduce the access time, fluoroscopy time, and postoperative decrease in hemoglobin level. No difference was found in the successful dilation rate, stone-free rate, transfusion rate, or rate of complications between the OSD and serial dilation groups. The difference in the length of postoperative hospital stay was uncertain. OSD may be a better method of tract creation for PCNL