Surface morphologies of Mg-Gd alloy particle during its reactions with O_(2) and Teflon

Mg-Gd alloy particle has exhibited its unique combustion properties as the fuel of Mg/Teflon/Viton(MTV).Mg-Gd alloy/Teflon/Viton(MGTV)could burn at lower ambient pressure than MTV.To further investigate the reaction of MGTV in air,it was investigated via thermo gravity-differential scanning calorimetry(TG-DSC).Meanwhile,the morphologies and element distributions on the alloy surface during the reaction of MGTV in air were investigated via scanning electronic microscope-mapping-electronic differential spectrometer.Meanwhile,a similar experimental protocol on the Mg-Gd alloy particle during oxidation was also applied.The results showed that owning to a protective oxide shell,the onset oxidation temperature of Mg-Gd alloy is higher than Mg.However,the onset oxidation temperature of the exceeded Mg-Gd alloy in MGTV is significantly lower than that of the exceeded Mg in MTV.It was due to the existence of GdOF,which could significantly lower the oxidation temperature of the exceeded fuel.Furthermore,a possible reaction mechanism was proposed.The fascinating oxidation properties of Mg-Gd alloy suggested its promising applications in energetic materials.

Characterization of Flame Retardancy and Oil-Water Separation Capacity of Superhydrophobic Silylated Melamine Sponges

A silylated melamine sponge(SMS)was prepared by two simple steps,namely,immersion and dehydration of a melamine sponge coated with methyltrichlorosilane.The silylated structure of SMS was characterized by FT-IR(Fourier-transform infrared)spectroscopy,SEM(Scanning electron microscopy)and in terms of water contact angles.Its oil-water absorption and separation capacities were measured by FT-IR and UV-visible spectrophoto-metry.The experimental results have shown that oligomeric silanol covalently bonds by Si-N onto the surface of melamine sponge skeletons.SMS has shown superhydrophobicity with a water contact angle exceeding 150°±1°,a better separation efficiency with regard to diesel oil(by 99.31%(wt/wt%)in oil-water mixture and even up to 99.99%(wt/wt%)for diesel oil in its saturated aqueous solution.Moreover,SMS inherited the intrinsicflame retardancy of the melamine sponge.In general,SMS has shown superhydrophobicity,high porosity,excellent selectivity,remarkable recyclability,and better absorption capacity for various oils and organic solvents,and a high separation efficiency for oil in saturated aqueous solutions.

Evolution of Superconducting-Transition Temperature with Superfluid Density and Conductivity in Pressurized Cuprate Superconductors

What factors fundamentally determine the value of superconducting transition temperature Tc in high temperature superconductors has been the subject of intense debate.Following the establishment of an empirical law known as Homes'law,there is a growing consensus in the community that the Tc value of the cuprate superconductors is closely linked to the superfluid density(ρ_(s))of its ground state and the conductivity(σ)of its normal state.However,all the data supporting this empirical law(ρ_(s)=AσT_(c))have been obtained from the ambientpressure superconductors.In this study,we present the first high-pressure results about the connection of the quantities of ρ_(s) and σ with T_(c),through the studies on the Bi_(1.74)Pb_(0.38)Sr_(1.88)CuO_(6+δ)and Bi_(2)Sr_(2)CaCu_(2)O_(8+δ),in which the value of their high-pressure resistivity(ρ=1/σ)is achieved by adopting our newly established method,while the quantity ofρs is extracted using Homes'law.We highlight that the Tc values are strongly linked to the joint response factors of magnetic field and electric field,i.e.,ρ_(s) and σ,respectively,implying that the physics determining T_(c) is governed by the intrinsic electromagnetic fields of the system.

Supramolecular complex glycoconjugate vaccine generates self-enhancement effects for carbohydrate antigen delivery

Targeting delivery of tumor-associated carbohydrate antigen(TACA)-based vaccine to antigen-presenting cells(APCs)mediated by endogenous antibodies can improve the immunogenicity of TACA.However,an essential requirement of this approach is to generate high titers of endogenous antibodies in vivo through pre-immunization,which complicates the immunization procedure and may cause side effects.Herein,we report a new generation of APC-targeting TACA-based supramolecular complex vaccine,assembled by sialyl Thomsen-nouveau-bovine serum albumin-adamantine(sTn-BSA-Ada)and heptavalent rhamnose(Rha)-modifiedβ-cyclodextrin(β-CD)via host-guest interaction.The complex vaccine retained anti-Rha antibodies recruiting capability and facilitated the APCs uptake of the vaccine via the interaction of the Fc-domain with the Fc receptors on APCs.We demonstrate that direct immunization of complex vaccine elicited anti-Rha and anti-sTn specific immune response synchronously,generating a novel self-enhancement effect that can improve the antigen delivery to APCs in high efficacy.The structure-activity relationship(SAR)study proved that complex vaccine 4 with polyethylene glycol 6(PEG 6)linker in host molecule provoked a robust and specific sTn immune response comparable to the pre-immunization approach.The antisera induced by complex vaccine,either through direct immunization or pre-immunization,exhibited equal potency of cytotoxicity against the sTn expression cancer cells.This study provides a general platform for TACA-based vaccines with self-enhancement effects without the need for pre-immunization.

Soil Organic Carbon Sequestration Potential in Nectarine Orchards under Different Reclamation Systems

The Red Soil Hilly Region in South China, where there is a high capacity of carbon(C), and the land use and vegetation cover change greatly, is an important ecological area in the world, and has an important impact on the global carbon cycle and the seasonal fluctuation of atmospheric CO_2. To better evaluate the effects of reclamation systems in orchards converted from grasslands on soil carbon sequestration, we investigated soil organic carbon(SOC) content and stable C isotope(δ^(13)C)composition in three nectarine orchards at Yuchi Experimental Station in South China. Compared with the sloping clean tillage orchard and terraced clean tillage orchard, SOC content in the terraced orchard with grass cover was increased by 14.90% to 38.49%, and 7.40% to 15.33%, respectively. During the 14 years after orchard establishment, the soil organic matter sources influenced both δ^(13)C distribution with depth and carbon replacement. SOC turnover of the upper soil layer in the terraced orchard with grass cover(a mean 63.05% of replacement in the 20 cm after 14 years) was 1.59 and 1.41 times larger than that of the sloping clean tillage orchard and terraced clean tillage orchard under subtropical conditions, respectively. The equilibrium value of soil organic carbon in the three treatments ranged from 16.067 to 25.608 g/kg under the experimental conditions. The equilibrium value of soil organic carbon in the surface layer under grass cover was 54.801 t/hm^2, and the carbon sequestration potential was 24.695 1 t/hm^2.

Effects of Main Meteorological Disasters and Their Defense Counterm easures in Ningxia

[ Objective] The study aimed to discuss effects of major meteorological disasters on national economic construction as well as people＇s lives and property in Ningxia. [Method] Based on data about meteorological disasters over the past 50 years and their direct economic losses dur- ing 2003-2011 in Ningxia, effects of major meteorological disasters on national economic construction as well as people＇s lives and property were discussed, and some defense countermeasures of meteorological disasters were put forward. [ Result] In Ningxia, drought, rainstorm and flood, gale and dust, hail and thunderstorm had done considerable harm to national economic construction as well as people＇s lives and property. Since 2003, total direct economic losses caused by all meteorological disasters in Ningxia changed from 1.28 billion to 1.97 billion yuan and accounted for 0.8% -3.1% of GDP of Ningxia. Among them, the direct economic losses caused by drought were the highest and annual average value during 2003 -2011 reached 1.22 billion yuan, accounting for 77.6% of total direct economic losses caused by all meteorological disasters in Ningxia. The direct economic losses caused by rainstorm, flood and hail ranked second, and their annual average values were 0.11 billion and 0.12 billion yuan, accounting for 7.4% and 7.6% of total direct economic losses. Meanwhile, annual average direct economic losses caused by thunderstorm in Ningxia reached 1.18 million yuan. In addition, annual average value of the direct economic losses caused by gale and dust totaled 0.01 billion yuan, with a proportion of 1.0%. [ Conclusion] The research could provide scientific references for the defense of meteorological disasters in future.

Efficient stereoselective hydroxylation of deoxycholic acid by the robust whole-cell cytochrome P450 CYP107D1 biocatalyst

Deoxycholic acid(DCA)has been authorized by the Federal Drug Agency for cosmetic reduction of redundant submental fat.The hydroxylated product(6β-OH DCA)was developed to improve the solubility and pharmaceutic properties of DCA for further applications.Herein,a combinatorial catalytic strategy was applied to construct a powerful Cytochrome P450 biocatalyst(CYP107D1,OleP)to convert DCA to 6β-OH DCA.Firstly,the weak expression of OleP was significantly improved using pRSFDuet-1 plasmid in the E.coli C41(DE3)strain.Next,the supply of heme was enhanced by the moderate overexpression of crucial genes in the heme biosynthetic pathway.In addition,a new biosensor was developed to select the appropriate redox partner.Furthermore,a cost-effective whole-cell catalytic system was constructed,resulting in the highest reported conversion rate of 6β-OH DCA(from 4.8%to 99.1%).The combinatorial catalytic strategies applied in this study provide an efficient method to synthesize high-value-added hydroxylated compounds by P450s.

Research progress on resource utilization of leather solid waste

Leather making is the process of converting raw hides into leather.Amounts of solid waste containing hazardous and high value components are generated during this process.Therefore,the elimination of the potential pollution and resource utilization of leather solid waste are the primary research hotspots.Herein,we comprehensively review the recent advances in the resource utilization of leather solid waste generated from chrome tanning including the utilization of tannery hair waste,untanned solid waste,chrome-containing leather solid waste,tannery sludge and finished leather waste,emphasizing on the general and novel utilization approaches.Finally,the remaining challenges and perspectives were summarized,in order to accelerate the development of resource utilization of leather solid waste.

Association Between rs1815739 Polymorphism of ACTN3 Gene and Athletic Ability in Chinese Sprinters

Purpose The aim of this study was to investigate the prevalence of the ACTN3 rs1815739 polymorphism and to study its association with athletes'level of competition and lower-extremity power.Method Time-of-flight mass spectrometry(TOFMS)and polymerase chain reaction-restriction fragment length polymor-phism(PCR-RFLP)techniques were employed to identify the ACTN3 rs1815739 genotypes and allele frequencies in 108 elite sprinters and 206 untrained controls.Questionnaires were then used to assess subjects'100 m sprint,standing jump(SJ)and standing triple jump(STJ)personal best record.Results(1)The RR,RX and XX genotype distribution of the ACTN3 rs1815739 polymorphism is 42.6%,49.1%,8.3%,respectively.R and X alleles frequency is 67.1%and 32.9%,respectively,which comply with Hardy Weinberg equilibrium(HWE)through Chi-square(x2)tests(x2=0.661;df=2;P=0.718).(2)Significant differences were found in R allele fre-quency between the elite sprinter group and controls.(3)The athletes'100 m sprint,SJ,and STJ personal best records were better in those with RR and RX than XX genotype.A significant association was observed between the R alleles and 100 m sprint,SJ,and STJ results of male and female athletes.Conclusion The present results indicate that ACTN3 rs1815739 polymorphism has a significant association with speed and lower-extremity power in sprint/power athletes.

Coil to globule transition of homo- and block-copolymer with different topological constraint and chain stiffness

In this paper, we present the coil-to-globule(CG) transitions of homopolymers and multiblock copolymers with different topology and stiffness by using molecular dynamics with integrated tempering sampling method. The sampling method was a novel enhanced method that efficiently sampled the energy space with low computational costs. The method proved to be efficient and precise to study the structural transitions of polymer chains with complex topological constraint, which may not be easily done by using conventional Monte Carlo method. The topological constraint affects the globule shape of the polymer chain, thus further influencing the CG transition. We found that increasing the topological constraint generally decreased CG transition temperature for homopolymers. For semiflexible chains, an additional first-order like symmetry-broken transition emerged. For block copolymers, the topological constraint did not obviously change the transition temperature, but greatly reduced the energy signal of the CG transition.