Sprayable coating based on fluorinated silica nanocomposites with superhydrophobic and antibacterial properties for advanced concrete

The porous hydrophilic nature of concrete structures makes them highly susceptible to chemical attack and bacterial adhesion, and the durability of concrete structures gradually decreases. In this work, a kind of sprayable coating with superhydrophobic and antibacterial properties was developed, which was used for surface engineering of concrete via the hydrophilic property of concrete and capillary action. The treated surface of concrete exhibited significant superhydrophobicity, with a static water contact angle of 162.4° and a sliding angle of 5°. The water absorption values of the treated concrete samples in merged in deionized water and 3.5 ?wt% NaCl solution for 7 days were measured as 1.85% and 2.71%, indicating the enhancement of water repellency by 72.03% and 80.11%, respectively. The antibacterial characterization revealed that the superhydrophobic coating enabled significantly reduced adhesion of bacteria, with the antibacterial rates of 84.57 ?± ?2.5% for E. coli and 90.43 ?± ?1.6% for S. epidermidis, respectively. The superhydrophobic coating provides hydrophobic protection for porous substrate structures and effectively reduce the corrosion damage of substrate materials, which is of practical significance for improving the durability of concrete structures.     

Time-resolved fluoroimmunoassay for quantitative determination of tylosin and tilmicosin in edible animal tissues

To quantitatively determine tylosin and tilmicosin in edible animal tissues,a time-resolved fluoroimmunoassay(TRFIA) has been developed and validated.For this purpose,desmycosin-O-carboxymethoxylamine-BSA was fixed onto microtiter plates,standards and samples were loaded and,finally,diluted europium-labeled anti-tylosin antibodies were added.Results show that the limit of detection for tylosin was 0.03 ng mL-1 and that for tilmicosin was 0.05 ng mL-1.The recoveries were 73.6% to 120.5%,with coefficients of variation below 15.6% in various biological matrices spiked with tylosin and tilmicosin at concentrations of 50-200 ngg-1.There was good correlation(R2>0.99) between the TRFIA,an enzyme-linked immunosorbent assay and high performance liquid chromatography data.In conclusion,the new TRFIA is applicable to the detection of tylosin and tilmicosin and is an effective and economical method that will enable high-throughput sample screening.The method is expected to be widely applicable.     

Highly stable N-containing polymer-based Fe/Nx/C electrocatalyst for alkaline anion exchange membrane fuel cell applications

A cost-effective electrocatalyst with high activity and stability was developed. The Fe-Nx and pyridinic-N active sites were embedded in nitrogen-doped mesoporous carbon nanomaterial by carbonization at high temperature. The electrocatalyst exhibited excellent electrochemical performance for the oxygen reduction reaction, with high onset potential and half-wave potential values (E_onset = 1.10 ?V and E_1/2 ?= ?0.944 ?V) than 20 ?wt % Pt/C catalyst (1.04 and 0.910 ?V). The mass activity of the Schiff base network (SNW) based SNW-Fe/N/C@800° electrocatalyst (0.64 ?mA ?mg^?1 @ 1 ?V) reached about half of the commercial Pt/C electrocatalyst (1.35 ?mA ?mg^?1 @ 1 ?V). The electrocatalyst followed the 4-electron transfer mechanism due to very low hydrogen peroxide yield (H₂O₂ ?< ?1.5%) was obtained. In addition, this electrocatalyst with dual active sites showed high stability during cyclic voltammetry and chronoamperometry measurements. More importantly, the electrocatalyst also demonstrated the power density of 266 ?mW ?cm^?2 in the alkaline anions exchange membrane fuel cell (AEMFC) test, indicating its prospective application for fuel cells.     

Efficient transfer and expression of human clotting factor IX cDNA in neonatal hemophilia B mice mediated by VSV-G pseudotyped retrovirus

The feasibility of in vivo gene therapy for hemophilia B by VSV-G pseudotyped retroviral vector was introduced. The novel packaging cell line 293GPG was used to produce VSV-G/G1NaBAIX pseudotyped virus with the highest titers up to 8.5×10⁸ cfu·mL^-1. In contrast to the conventional retrovirus, VSV-G pseudotyped virus was more resistant to inactivation by serum complements (P＜0.001). Our results also demonstrated that VSV-G pseudotyped virus was more stable in neonatal mice serum than in adult mice serum (P＜0.01). After intraperitoneal injection of different doses of virus, hFIX antigen was detected and lasted for more than 120 d, the highest level reached (72.5±6.1) ng·mL^-1. Moreover, the functional activity was improved to some extent in all hFIX-treated mice, the most remarkable improvement was observed in the mice treated with higher dose of virus whose clotting activity increased to (3.4±1.5)% and APTT (activated partial thromboplastin time) reduced to (43.2±7.2) s. The anti-hFIX antibody was not detected by the method of Bethesda, no germ line transmission and any side effects associated with gene transfer were found. Our results indicated that neonatal gene therapy for hemophilia B mice by VSV-G pseudotyped retrovirus is promising.     

Dexamethasone-Loaded PLGA Microspheres Incorporated PLLA/PLGA/PCL Composite Scaffold for Bone Tissue Engineering

The combination of micro-carriers and polymer scaffolds as promising bone grafts have attracted considerable interest in recent decades.The poly(L-lactic acid)/poly(lactic-co-glycolic acid)/polycaprolactone(PLLA/PLGA/PCL)composite scaffold with porous structure was fabricated by thermally induced phase separation(TIPS).Dexamethasone(DEX)was incorporated into PLGA microspheres and then loaded on the PLLA/PLGA/PCL scaffoldtopreparethedesiredcompositescaffold.The physicochemical properties of the prepared composite scaffold were characterized.The morphology of rat bone marrow mesenchymal stem cells(BMSCs)grown on scaffolds was observed using scanning electron microscope(SEM)and fluorescence microscope.The resultsshowedthatthePLLA/PLGA/PCLscaffoldhad interconnected macropores and biomimetic nanofibrous structure.In addition,DEX can be released from scaffold in a sustained manner.More importantly,DEX loaded composite scaffold can effectively support the proliferation of BMSCs as indicated by fluorescence observation and cell proliferation assay.The results suggested that the prepared PLLA/PLGA/PCL composite scaffold incorporating drug-loaded PLGA microspheres could hold great potential for bone tissue engineering applications.     

壳聚糖修饰的Lysozyme-PLGA阳离子纳米药物的制备与表征

通过二环己基碳二亚胺将聚乳酸-羟基乙酸共聚物(PLGA)活化,又与溶菌酶进行化学键合,再采用单乳化-溶剂挥发技术制备表面带正电荷的壳聚糖(CHS)PLGA纳米微球。对纳米微球制备条件进行了优化。结果表明在ρ(CHS)=3 mg/mL,ρ(PLGA)=5 mg/mL,溶菌酶与PLGA的质量比为0.2的条件下,得到的纳米微球包封率为87.8%,载药量为14.7%。微球粒径φ可控制在(450±50)nm之间,在pH=4时,纳米微球表面ζ电位为42.5mV。SEM图像显示经CHS修饰的Lysozyme-PLGA的纳米微球形状规整。药物释放试验显示纳米微球在20 d后释放达到70%,且释放曲线规整。     

Effective antibacterial and phase change PEG/Cu2O@A-HNTs composites for melt-spun difunctional PA6 fiber

Serving as the only defensive line between pathogens and human body, personal protective equipment (PPE) is increasingly attractive among researchers because of their strong antibacterial and temperature control abilities. However, efficient antibacterial properties and regenerative thermal control simultaneously remain unexplored in PPE. Here, one-dimensional halloysite nanotubes (HNTs) modified by acid etch method, are used to synthesis a multifunctional material of PEG/Cu₂O@A-HNTs via in-situ reduction and physical adsorption which serves the above two purposes. PEG/Cu₂O@A-HNTs showed rapid bacterial inactivation and achieved 96.3% bacteriostatic rate against E. coli in only 20 ?min. Meanwhile a broad and complete inactivation spectrum included both E. coli and S. aureus following a series of antibacterial mechanisms. Moreover, adsorption of 70 ?wt% PEG by acid etch HNTs is attributed to the nearly 3 times increased specific surface area compared with native HNTs. This enabled PEG/Cu₂O@A-HNTs to attain a phase change enthalpy of 108.4 ?J/g. In addition, using PEG/Cu₂O@A-HNTs as additives, antibacterial and phase change fiber (APCF) were melt-spun. Their efficiency factor against E. coli and S. aureus was above 99.99%, and retained a temperature control ability for 180s and 272s compared with PA6 fiber in hot and frigid environments respectively.     

Synthesis and antibacterial activities of selenide derivatives of Benzisoselenazolone

A series of Benzisolselenazolone (BISA) derivatives were synthesized and evaluated for their antibacterial activities againstE coli. by using LKB-2277 bioactivity monitor. Other bioactivities were tested by the method of High Throughput Screening for pharmaceutical activity compounds (HTP) BISA derivatives 3b, at the concentration of 40 μg/mL, showed 100% antibacterial activity and 62% inhibition rate of aldose reductase (at the concentration of 5μg/mL). These new compound structures have determined by IR,¹H NMR and MS spectra. Foundation item: Supported by Hubei Province Natural Science Fund (99J056) Biography: Yang Li-ping (1975-), female, Master, research direction: organic seleno-compound, antioxidation medicines, selenium-enriched garlic.     

A novel bimetallic RuFe nanocluster to enable highly efficient oxygen reduction in zinc-air batteries

Zinc-air batteries (ZABs) have the advantages of high energy density and safety but their large-scale application is hindered by sluggish kinetics of four-electron aqueous O₂ redox reactions. Widely used Ruthenium (Ru)-based catalysts possess intrinsic oxygen evolution catalytic activity but suffer from insufficient oxygen reduction reaction (ORR) performance. Herein, to optimize the ORR activity of Ru-based catalyst, an iron (Fe)-coordinated, bimetallic RuFe cluster is constructed and homogeneously dispersed within nitrogen (N)-doped carbon layers (denoted as RuFe@NC). Benefitting from the optimized ORR activity and more active site exposure, the RuFe@NC exhibits superior ORR activity with a half wave potential (E_1/2) of 0.88 ?V higher than that of Pt/C (0.82 ?V). Accordingly, the RuFe@NC-based ZAB outperforms the Pt/C ?+ ?IrO₂-based device, presenting a reduced polarization of 0.7 ?V and an enhanced cycling lifetime of 50 ?h at 10 ?mA ?cm^?2. Moreover, the optimized structural design ultralow Ru loading (0.013 mg_Ru cm^?2) overcomes the cost barriers and demonstrates its high practicality. This bimetallic RuFe nanocluster opens a new way for future design of more efficient and stable catalytic systems.     

Mangosteen peel-derived activated carbon for supercapacitors

This work reports the effects of activation temperatures on the porous development and electrochemical performance of activated carbons. Herein, activated carbons were prepared from the biowaste of mangosteen peel by using KOH activation at temperatures of 400, 600, and 800 ?°C. The results demonstrate that the specific surface area increases with increasing the activation temperatures in which the well-developed porous structure after KOH activation at 800 ?°C provides the highest specific surface area of 1039 ?m² ?g^?1. At 600 ?°C, the activated carbon delivers the highest specific capacitance value of 182 ?F ?g^?1 ?at a current density of 0.5 ?A ?g^?1 in 3 ?M KOH aqueous electrolyte. This is correlated well with its high micropore fractions (99%). Moreover, it was found that the activation temperature changes the major contribution of oxygen-containing functional group on surface of activated carbon, which is beneficial for the enhancement of the specific capacitance value of activated carbon at the temperature of 600 ?°C. This work suggests that the activation temperature is a key to optimizing the electrochemical performance of activated carbons. Overall, our activated carbons can be considered as a strong candidate for use as electrode materials in supercapacitors.     

Enhanced low-humidity performance of proton-exchange membrane fuel cell by introducing hydrophilic CNTs in membrane electrode assembly

Hydrophilic carbon nanotubes (HCNTs) were introduced into the membrane electrode assembly (MEA) to improve its low-humidity performance. The effects of types, placement, loading, and relative humidity on the MEA performance were investigated. It has been found that the MEA with 20 ?wt% HCNTs loading both in anode and cathode achieved the best self-humidifying performance. Its current density reached 1550 ?mA ?cm^?2 at 0.6 ?V, with a maximum power density of 953 ?mW/cm² at 70 ?°C, 30 psi and 30% relative humidity conditions. Besides, the stability test shows that its current density at 0.6 ?V only decreased by 6.4% after 44 ?h performance test, while the performance of blank MEA without HCNTs decreased by 45% within 6 ?h testing period. This extraordinary performance under low humidity condition is ascribed to that the HCNTs contained in the MEA improve the water management and mass transportation by functioning as a dispersant and hydrophilic agent.     

Flexible micro-supercapacitors fabricated from MnO2 nanosheet/graphene composites with black phosphorus additive

Supercapacitors are widely used for powering flexible/wearable electronics owing to their excellent charge storage capabilities. In this study, MnO₂ nanosheets were grown on the surface of graphene using a simple water bath method to prepare graphene/MnO₂ composites for fabricating supercapacitors. In addition, two-dimensional black phosphorus was introduced as an additive into the electronic ink based on the as-prepared graphene/MnO₂ composites. The characterization and electrochemical analyses results showed that adding black phosphorus considerably improved the capacitive performance of the material, yielding a high specific capacitance of 241.5 ?F ?g^-1 at 0.1 ?A ?g^-1 and an impressive rate capability improvement from 52.5% to 80.3%. Then the micro-supercapacitor having an area-specific capacitance of 20.15 ?mF ?cm^-2 at a scanning rate of 2 ?mV ?s^-1 was utilized to demonstrate the practical applicability of this material. To further evaluate the practical applicability of this micro-supercapacitor, the micro-supercapacitor was integrated with a flexible thin-film pressure sensor on paper and cloth through screen printing.     

Cu2O-templated fabrication of Ni(OH)2·0.75H2O hollow tubes for electrocatalytic oxygen evolution reaction

Cu₂O is an ideal template material for the preparation of transition metal hydroxide/oxyhydroxides with oxygen evolution reaction (OER) enhanced catalytic performance. Here, inspired by Pearson's principle, Cu₂O wires were prepared and used as a sacrificial template to prepare Ni(OH)₂·0.75H₂O hollow tubes (Ni(OH)₂ HTs) with highly improved surface roughness. Benefiting from unique structural advantages, the Ni(OH)₂ HTs showed excellent catalytic activity, rapid kinetics and a long-term stability as the OER catalyst, where an overpotential of only 207 ?mV was required to drive a current density of 10 ?mA ?cm^?2, an ideal kinetics with a Tafel slope as 79.8 ?mV dec^?1 was calculated, and no obvious attenuation in chronoamperometry was discovered after operation for 24 ?h. This paper provides a novel template-assisted strategy to prepare high-performance transition metal-based OER catalysts possessing hollow and tubular structures.     

Scalable synthesis and electrochemical performance of mesoporous graphene from calcium carbonate by magnesiothermic reaction

A novel scalable synthetic method of mesoporous graphene has been developed using the compressed mixture of Mg and excess CaCO₃ in a closed container. The generated solid oxide and unreacted CaCO₃ could act as mesopore-forming agents, and the closed container could prevent the carbon dioxide from CaCO₃ flow away. As a result, the graphenes with a large number of 2–30 ?nm mesopores and high utilization ratio of Mg achieved. The graphenes had high specific surface area and excellent electrochemical performance. In particular, the Mg utilization ratio was up to 53.3% in the preparation of graphene using 2:1 CaCO₃/Mg at 700 ?°C, which is superior to previous researches. The obtained mesoporous graphene exhibited high specific surface area of 743.7 ?m² ?g^-1, large specific capacitance of 140 ?F ?g^-1, and high capacitance retention rate of 64.3%.     

Fluorescent immunosensor based on fluorescence resonance energy transfer between CdSe/ZnS quantum dots and Au nanorods for PRRSV detection

An ultrasensitive and selective sandwich-type fluorescent immunosensor based on fluorescence resonance energy transfer (FRET) between CdSe/ZnS quantum dots (QDs) and Au nanorods (AuNRs) was developed for the rapid detection of porcine reproductive and respiratory syndrome virus (PRRSV). Modified CdSe/ZnS QDs and AuNRs were bioconjugated with primary antibodies M and GP5, respectively. When the target antigen was present, a well-known sandwich-type form CdSe/ZnS QDs-M antibody-antigen-GP5 antibody-AuNRs was produced, and thus reducing the distance between the QDs and NRs. As a result, FRET occurred and the fluorescence intensity of CdSe/ZnS QDs decreased, and this decrease was used to determine the antigen concentration. Ultrasensitive detection of PRRSV at low concentrations in swine serum was achieved with a limit of detection of 0.55 TCID₅₀/mL and a linear detection range of 10¹–3.5 ?× ?10⁴ TCID₅₀/mL. Therefore, the fluorescent immunosensor is selective and highly sensitive; specifically, it can detect PRRSV at low concentrations in swine serum over a large concentration range. This proposed detection method can facilitate the development of high-performance fluorescent immunosensors for the detection of PRRSV and other antigens.     

Graphene oxide-covered melamine foam utilizing as a hybrid foam toward organic dye removal and recyclability

Graphene-based adsorbents have been attracted extensive interest in recent years. Herein, graphene oxide-covered melamine foam (GO-covered MF) was designed and prepared by a mild submerge-covering method with the support of a super-hydrophilic melamine framework, showing its adsorption performances for various organic dyes. The structure morphology as well as chemical, thermal and mechanical properties of the as-obtained hybrid foam (HF) were further determined for the possible structure changes after covering the GO sheets on the MF framework. Moreover, the HF exhibited an excellent ability for organic dye adsorption application, and which was well fitted in the pseudo-second-order kinetic and Langmuir models corresponding to a chemical adsorption and a mono-layer approach during the adsorption process. The maximum adsorption capacity by using the as-obtained HF corresponded to 258.56 ?mg ?g^?1 (methylene blue), 233.22 ?mg ?g^?1 (Rhodamine B), 206.92 ?mg ?g^?1 (methyl orange), and 184.93 ?mg ?g^?1 (Congo red), which are competitive with that of other graphene-based absorbents. In particular, the HF could be reused without a noticeable degradation of organic dye removal performance. As such, the HF prepared in this study can become an encouraging candidate for practical application owing to the reliable recyclability and low-cost.     

Fabricating polymer/HEA-hybrid topological lattice structure for enhanced mechanical properties

Metamaterials such as architected lattice structures have aroused broad interest in being applied as mechanical supports for their lightweight and custom-shaped capabilities. Although various prior efforts have been devoted, a multiscale fabrication of micro-nano lattice structures without penalizing the mechanical properties is still a challenging but highly desirable task. Here we put forward a strategy to produce a mechanically enhanced micro-nano lattice structure by conformally depositing a CoCrFeNiTi high-entropy alloy (HEA) coating layer onto a three-dimensional (3D) printed polymer skeleton. The template for the 3D printing employs a six-membered tricapped trigonal prism (6M-TTP) structure derived from a medium-range order structure motif in amorphous alloys. The topological complexity of the 6M-TTP can substantially avoid the stress concentration by offering stress-release channels, while the HEA film incorporating with amorphous and nanocrystalline constituents can further reinforce the lattice architecture through its size hardening effect. Benefitting from the above, the fabricated polymer/HEA-hybrid lattice exhibits a high specific compressive strength (～0.055 ?MPa ?kg^-1 m³ at a density below 500 ?kg ?m^-3), a superior elastic recoverability (～70% recovery rate under >30% compression), an enhanced plasticity (40% strain) and a high specific modulus (0.135 ?MPa ?kg^-1 m³). Our strategy initiates a perspective way to fabricate multiscale micro-nano lattice structures with improved mechanical properties, which could be extended to widespread metamaterial research.     

SiO_2@CaF_2:Eu~(3+)核壳纳米球的制备及发光性能研究

以正硅酸乙酯(TEOS)为硅源,采用Stber反应制备了平均粒径为250nm的SiO2纳米球,然后以柠檬酸为表面活性剂和修饰剂,在水醇体系中,利用均相沉淀法制备了SiO2@CaF2:Eu3+核壳纳米球,并对其进行了煅烧处理.运用X-射线粉末衍射(XRD),傅立叶变换红外光谱仪(FT-IR)以及透射电子显微镜(TEM)分别对产物的物相、表面性质及形貌尺寸进行了分析表征.最后,使用荧光分光光度计对样品的激发和发射光谱进行了分析.结果表明,CaF2:Eu3+包覆在非晶态的SiO2表面,该样品具有很好的荧光性能.     

药物中半胱氨酸的流动注射荧光测定方法研究

 在近中性介质及聚乙烯醇(PVA)存在下,半胱氨酸能熄灭一个新的荧光试剂5-(4-氯苯基)-8-苯磺酰氨基喹啉(CPBSQ)与Cu(Ⅱ)络合体系的荧光的反应.基于此现象,本文建立了一个测定半胱氨酸的流动注射荧光熄灭方法.结果表明,在λ_ex/λ_em=327/368nm处测定,方法的进样频率为64h-1,检测范围为0.05～5.5μg·mL^-1,检出下限为0.01μg·mL^-1,对4.0μg·mL^-1半胱氨酸平行测定11次的相对标准偏差为1.52%.大量存在的常见金属离子、蛋白质及很多不带巯基的氨基酸不干扰测定.应用此方法测定了某些注射液针剂中半胱氨酸的含量,结果满意.     

Spatial variability of cyanobacterial community composition in Sanya Bay as determined by DGGE fingerprinting and multivariate analysis

The cyanobacterial communities in the surface and bottom waters of Sanya Bay were investigated on April 24 and 25,2010.Flow cytometry showed that the total cyanobacterial abundance in the surface and bottom layers ranged from 0.7×10 4 to 2.38×10 4 cells mL-1 and from 1×10 4 to 1.8×10 4 cells mL-1,respectively.Cyanobacterial diversity was analyzed using a molecular fingerprinting technique called denaturing gradient gel electrophoresis(DGGE),followed by DNA sequencing.The results were then interpreted through multivariate statistical analysis.Differences in the compositions of cyanobacterial communities were observed in the surface and bottom waters at the same station,with some bands obtained from both the surface and bottom layers,whereas some bands were present only in one layer.The predominant cyanobacterial species of the excised DGGE bands were related to Synechococcus or Synechococcus-like species(56.2%).Other phylogenetic groups identified included Chroococcidiopsis(6.3%),Cyanobium(6.3%) and some unclassified cyanobacteria(31.2%).A redundancy analysis(RDA) was conducted to reveal the relationships between the cyanobacterial community composition and environmental factors.Analysis results showed that the spatial variations in the cyanobacterial community composition in surface waters was significantly related to chlorophyll a(Chla),the biochemical oxygen demand(BOD),nitrate and phosphate(P<0.05).Meanwhile,the spatial variations in the bottom waters was significantly affected by nitrate,nitrite,and phosphate(P<0.05).Environmental parameters could explain 99.3% and 58.3% of the variations in the surface and bottom layers,respectively.