A NOVEL FIRE RETARDANT AFFECTS FIRE PERFORMANCE AND MECHANICAL PROPERTIES OF WOOD FLOUR-HIGH DENSITY POLYETHYLENE COMPOSITES

Wood flour-high density polyethylene (HDPE) composites were prepared to investigate the effects of ammonium polyphosphate based fire retardant content (2, 4, 6, 8, and 10-wt%), on the flammability, mechanical, and morphological properties of the wood flour-HDPE composites in this study. Cone calorimetry analysis showed that the addition of fire retardant could decrease the heat release rate (HRR) and total smoke release of wood flour-HDPE composites, while it had no obviously effects on effective heat of combustion. Most of the decrease of the HRR occurred with the concentration of the fire retardant up to 4-wt%. With addition of fire retardant, the composites showed a decrease in tensile elongation at break and impact strength, and had no obvious effect on tensile and flexural strength. The scanning electron microscopy observation on the fracture surface of the composites indicated that fire retardant had a uniform dispersion in the wood flour-HDPE composites. However, interfacial bonding would be suggested to improve in wood flour-HDPE composites with ammonium polyphosphate based fire retardant

Stemazole Promotes Oligodendrocyte Precursor Cell Survival In Vitro and Remyelination In Vivo

Maintaining the normal function of oligodendrocyte precursor cells (OPCs) and protecting OPCs from damage is the basis of myelin regeneration in multiple sclerosis (MS). In this paper, we investigated the effect of stemazole, a novel small molecule, on the promotion of oligodendrocyte precursor cell survival and remyelination. The results show that stemazole enhanced the survival rate and the number of clone formation in a dose-dependent manner and decreased the percentage of cell apoptosis. In particular, the number of cell clones was increased up to 6-fold (p < 0.001) in the stemazole group compared with the control group. In vivo, we assessed the effect of stemazole on recovering the motor dysfunction and demyelination induced by cuprizone (CPZ). The results show that stemazole promoted the recovery of motor dysfunction and the repair of myelin sheaths. Compared with the CPZ group, the stemazole group showed a 30.46% increase in the myelin area (p < 0.001), a 37.08% increase in MBP expression (p < 0.01), and a 1.66-fold increase in Olig2 expression (p < 0.001). Histologically, stemazole had a better effect than the positive control drugs. In conclusion, stemazole promoted OPC survival in vitro and remyelination in vivo, suggesting that this compound may be used as a therapeutic agent against demyelinating disease

Influence of Human Papillomavirus Infection on the Natural History of Cervical Intraepithelial Neoplasia 1: A Meta-Analysis

Objective. To provide a scientific basis for the prevention and treatment of cervical intraepithelial neoplasia grade 1 (CIN1). This study evaluated the impact of human papillomavirus (HPV) infection on the natural history of CIN1. Methods. Electronic databases of Cochrane Library, EMBASE, PubMed, CNKI, CBM, and Wanfang were searched in April 2016. The eligibility criteria were documented by Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). We used the Newcastle-Ottawa scale (NOS) to assess study quality. Results. Thirty-eight studies out of 3,246 identified papers were eligible for inclusion. The risk of CIN1 progression (relative risk [RR]: 3.04; 95% confidence interval [CI]: 2.41–3.83; P<0.00001) and persistence (RR: 1.48; 95% CI: 1.17–1.87; P=0.001) was higher in the HPV-positive group than HPV-negative group. Specifically, the risk of CIN1 progression (RR: 13.91; 95% CI: 3.46–55.90; P=0.000) was higher among persistent high-risk HPV-positive patients and the ratio of CIN1 regression (RR: 0.65; 95% CI: 0.59–0.71; P<0.00001) was lower in the HPV-positive group than HPV-negative group. Conclusion. HPV infection resulted in an increased risk of CIN1 progression and decreased disease reversibility. Persistent high-risk HPV infection resulted in a further increased risk of CIN1 progression

Local Supersaturation Dictated Branching and Faceting of Submicrometer PbS Particles with Cubic Growth Habit

Hierarchical cubelike submicrometer PbS particles consisting of truncated octahedrons, cuboctahedrons, and cubes were prepared in ethylene glycol solution under favorable high mole ratio of thiourea (Tu) to Pb(AC)(2) (R-S/(Pb)) via a pumping process. A qualitative analysis based on the classical nucleation theory coupled with the crystal growth theory is employed to interpret the observed experimental phenomena. By varying the concentration of reactants, R-S/(Pb), and reaction temperature, it is possible to tune the local supersaturation degree (LSD), which is determined by the number of nuclei and overall growth unit (or concentration), surrounding each growing particle that dictates the branching and faceting of PbS particle. Relatively high LSD that is required for branching growth could be achieved at lower concentration of Tu and reaction temperature. Increasing the concentration of Tu and reaction temperature resulted in less LSD and yielded cubic PbS particles

Mechanically adaptive nanocomposites with cellulose nanocrystals: Strain-field mapping with digital image correlation

Strain-transfer plays a key role in overall modulus of mechanically adaptive nanomaterials. Herein, mechanically adaptive nanocomposites were prepared via introducing cellulose nanocrystal (CNC) percolating network into poly butyl methacrylate (PBMA) with polyethylene glycol (PEG) as a stabilizer. The prepared PBMA/CNC nanocomposites were soaked in deionized water at 23 °C and 37 °C for one week to investigate their mechanically adaption. The interactions between PEG, CNC, and PBMA were assessed by Fourier Transform infrared, X-ray diffraction, and X-ray photoelectron spectroscopy. Incorporation of PEG to CNC and PBMA/CNC nanocomposites on the morphological and thermal properties was also investigated. The mechanical adaption of PBMA/CNC nanocomposites after switching dry-to-wet state and surrounding temperature (soaked in deionized water at 23 °C and 37 °C for one week, respectively) was evaluated by mechanical testing. Meantime, digital image correlation (DIC) was firstly used to study strain transfer mechanism in mechanical adaption which was carried out in real-time synchronized with mechanical measurement. It indicated that PEG improved the dispersion of CNC in PBMA/CNC nanocomposite and its thermal properties. Furthermore, CNC with PEG modification bridged PBMA during crack propagation and promoted the stress and stain transfer in PBMA/CNC nanocomposites according to DIC analysis

Fast Microwave Synthesis of Hierarchical Porous Carbons from Waste Palm Boosted by Activated Carbons for Supercapacitors

The synthesis of biomass-derived porous carbons (PCs) for supercapacitors by conventional two-steps method (chemical activation after carbonization) is complicated and time-consuming. In this study, we present a one-step microwave activation strategy to prepare hierarchically PCs from waste palm boosted by activated carbons (ACs). ACs with various specific surface areas (14, 642, and 1344 m2&middot;g&minus;1) were used for the first time to fast absorb microwave energy for converting waste palm into hierarchically PCs, that is, PC1, PC2, and PC3, respectively. The morphological and structural characterizations of PCs were studied. Also, the electrochemical performances of supercapacitors based on PCs as electrodes were further investigated. The results showed that the PC (PC1) boosted by AC with the lowest specific surface area possessed a porous structure (containing micro-, meso-, and macro- pores) with the largest specific surface area (1573 m2&middot;g&minus;1) and the highest micropore volume (0.573 cm3&middot;g&minus;1), as well as the suitable mesoporosity (29.69%). The as-prepared PC1 supercapacitor even in a gel electrolyte (PVA/LiCl) exhibited a high specific capacitance of 226.0 F&middot;g&minus;1 at 0.5 A&middot;g&minus;1 and presented excellent charge-discharge performance with an energy density of 72.3 Wh&middot;kg&minus;1 at a power density of 1.4 kW&middot;kg&minus;1 and 50.0 Wh&middot;kg&minus;1 at 28.8 kW&middot;kg&minus;1. Moreover, this promising method exhibited a simple, rapid, and cost-effective preparation of carbon materials from renewable biomass for energy storage applications

Cuticular Wax Modification by <i>Epichloë</i> Endophyte in <i>Achnatherum inebrians</i> under Different Soil Moisture Availability

The cuticular wax serves as the outermost hydrophobic barrier of plants against nonstomatal water loss and various environmental stresses. An objective of this study was to investigate the contribution of the mutualistic fungal endophyte Epichloë gansuensis to leaf cuticular wax of Achnatherum inebrians under different soil moisture availability. Through a pot experiment and gas chromatography−mass spectrometry (GC−MS) analysis, our results indicated that the hydrocarbons were the dominant components of leaf cuticular wax, and the proportion of alcohols, aldehydes, amines, and ethers varied with the presence or absence of E. gansuensis and different soil moisture availability. Amines and ethers are unique in endophyte-free (EF) A. inebrians plants and endophyte-infected (EI) A. inebrians plants, respectively. By transcriptome analysis, we found a total of 13 differentially expressed genes (DEGs) related to cuticular biosynthesis, including FabG, desB, SSI2, fadD, BiP, KCS, KAR, FAR, and ABCB1. A model is proposed which provides insights for understanding cuticular wax biosynthesis in the association of A. inebrians plants with E. gansuensis. These results may help guide the functional analyses of candidate genes important for improving the protective layer of cuticular wax of endophyte-symbiotic plants

Rapid microwave activation of waste palm into hierarchical porous carbons for supercapacitors using biochars from different carbonization temperatures as catalysts

A rapid, simple and cost-effective approach to prepare hierarchical porous carbons (PCs) for supercapacitors is reported by microwave activation of abundant and low-cost waste palm, biochar (BC) and KOH. BCs from waste palm at different carbonization temperatures (300-700 °C), as catalysts and microwave receptors, were used here for the first time to facilitate the conversion of waste palm into hierarchical PCs. As a result, the high-graphitization PC obtained at a BC carbonization temperature of 300 °C (PC-300) possessed a high surface area (1755 m g), a high pore volume (0.942 cm g) and a moderate mesoporosity (37.79%). Besides their high-graphitization and hierarchical porous structure, the oxygen doping in PC-300 can also promote the rapid transport of electrolyte ions. The symmetric supercapacitor based on the PC-300 even in PVA/LiCl gel electrolyte exhibited a high specific capacitance of 164.8 F g at a current density of 0.5 A g and retained a specific capacitance of 121.3 F g at 10 A g, demonstrating a superior rate capacity of 73.6%. Additionally, the PC-300 supercapacitor delivered a high energy density of 14.6 W h kg at a power density of 398.9 W kg and maintained an energy density of 10.8 W h kg at a high power density of 8016.5 W kg, as well as an excellent cycling stability after 2000 cycles with a capacitance retention of 92.06%

Comparison of Biochar Materials Derived from Coconut Husks and Various Types of Livestock Manure, and Their Potential for Use in Removal of H2S from Biogas

As a potential adsorbent material, loose, porous livestock manure biochar provides a new approach to livestock manure resource utilization. In this study, coconut husks (CH) and livestock manure, i.e., cow dung (CD), pig manure (PM), and chicken manure (CM) were used as biomass precursors for preparation of biochar via high-temperature pyrolysis and CO2 activation. Characterization technologies, such as scanning electron microscopy, Fourier transform infrared spectroscopy, adsorption–desorption isotherms, and pore size distributions, were used to study the microscopic morphologies and physicochemical properties of unactivated and activated biochar materials. The results showed that CD biochar provides better adsorption performance (up to 29.81 mg H2S/g) than CM or PM biochar. After activation at 650° for 1 h, the best adsorption performance was 38.23 mg H2S/g. For comparison, the CH biochar removal performance was 30.44 mg H2S/g. Its best performance was 38.73 mg H2S/g after 1 h of activation at 750 °C. Its best removal performance is equivalent to that of CH biochar activated at a temperature that is 100 °C higher. Further material characterization indicates that the H2S removal performance of livestock-manure–derived biochar is not entirely dependent on the specific surface area, but is closely related to the pore size distribution