Growth and acetylene reduction activity ofAzolla caroliniana Willd. as influenced by split applications of urea fertilizer and their response on rice yield

Experiment with different split applications of 40 kg N ha^–1 of urea (U) at transplanting:30 days after transplanting:40 days before crop maturity with different proportions of 50:25:25, 25:50:25 and 0:50:50 splits, with and without Azolla, carried out for two consecutive seasons, revealed that fresh weight (FW), N₂-fixation measured by acetylene reduction activity (ARA) and N yield of newly introducedAzolla caroliniana were higher with 0:50:50 treatment followed by 25:50:25 and 50:25:25.Azolla was unincorporated and left for self decomposition. The crop yield (grain yield, straw yield) and crop N uptake data indicated that among the no Azolla treatments, the use of 50:25:25 split resulted in highest crop yield and crop N uptake followed by 25:50:25 and 0:50:50 treatments, while these parameters recorded maximum value with 25:50:25 split in combination with Azolla followed by 50:25:25 and 0:50:50 treatments. The use of Azolla increased crop yield and crop N uptake significantly over no Azolla treatments.     

生物降解材料PLGA50的直接法合成与表征

分别以外消旋乳酸(D,L-LA)和左旋乳酸(L-LA)为原料,通过与乙醇酸(GA)熔融共聚[n(GA):n(LA)=1:1],直接合成了生物降解材料聚(乳酸-乙醇酸)(PLGA50)。用特性黏度[鏬、凝胶渗透色谱(GPC)、傅立叶红外光谱(FTIR)、核磁共振氢谱(1H　NMR)、差热分析(DSC)、X-射线衍射、接触角测试等手段,对PLGA50的相对分子质量、结构、性能等进行了系统的表征。PLGA50为无定型高分子,相同合成条件下D,L-PLGA50的相对分子质量比L-PLGA50高,其亲水性能比外消旋聚乳酸(PDLLA)有所改善。     

Proposal and evaluation of a new norm index-based QSAR model to predict pEC50 and pCC50 activities of HEPT derivatives☆

The search and development of anti-HIV drugs is currently one of the most urgent tasks of pharmacological studies.In this work,a quantitative structure–activity relationship(QSAR) model based on some new norm indexes,was obtained to a series of more than 150 HEPT derivatives(1-[(2-hydroxyethoxy)methyl]-6-(phenylthio)thymine) to find their pEC_(50)(the required effective concentration to achieve 50% protection of MT-4 cells against the cytopathic effect of virus) and pCC_(50)(the required cytotoxic concentration to reduce visibility of 50% mock infected cell) activities.The model efficiencies were then validated using the leave-one-out cross validation(LOO-CV) and yrandomization test.Results indicated that this new model was efficient and could provide satisfactory results for prediction of pEC_(50) and pCC_(50) with the higher R_(train)~2 and the higher R_(test)~2.By using the leverage approach,the applicability domain of this model was further investigated and no response outlier was detected for HEPT derivatives involved in this work.Comparison results with reference methods demonstrated that this new method could result in significant improvements for predicting pEC_(50) and pCC_(50) of anti-HIV HEPT derivatives.Moreover,results shown in this present study suggested that these two absolutely different activities pEC_(50) and pCC_(50) of anti-HIV HEPT derivatives could be predicted well with a totally similar QSAR model,which indicated that this model might have the potential to be further utilized for other biological activities of HEPT derivatives.     

Synthesis and properties of methacrylate-based ionic networked polymers containing ionic liquids: comparison of ionic and nonionic networked polymers

Ionic networked polymers containing ionic liquids were synthesized by radical copolymerization of 1-(2-methacryloyl)ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (Met-IL) and difunctional or trifunctional methacrylate cross-linkers, ethylene glycol dimethacrylate (EGDMA), or trimethylolpropane trimethacrylate (TMPTMA) in the presence of an ionic liquid, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (EMImTFSI). For comparison, nonionic networked polymers containing the ionic liquid were prepared by radical copolymerization of methyl methacrylate (MMA) with EGDMA in the presence of EMImTFSI. Met-IL/EGDMA/EMImTFSI(50) showed higher ion conductivity and ionic liquid holding ability than the corresponding MMA/EGDMA/EMImTFSI(50), while Met-IL/TMPTMA/EMImTFSI(50) showed lower ionic conductivity with higher holding ability than MMA/EGDMA/EMImTFSI(50).     

Structural and morphological development in poly(ethylene-co-hexene) and poly(ethylene-co-butylene) blends due to the competition between liquid-liquid phase separation and crystallization

Isothermal crystallization behavior of poly(ethylene-co-hexene) (PEH) and the 50/50 blend (H50) of PEH with amorphous poly(ethylene-co-butylene) (PEB) was studied by time-resolved synchrotron simultaneous small-angle X-ray scattering/wide-angle X-ray diffraction (SAXS/WAXD) techniques and optical microscopy (OM). The X-ray study revealed the changes of structural and morphological variables such as the scattering invariant, crystallinity and lamellar long period, et al. In H50, the lamellar morphology was found to be dependent on competition between liquid-liquid phase separation (LLPS) and crystallization. At high temperature, LLPS becomes dominating, resulted in crystallization of PEH with minimal influence of PEB. At low temperature, LLPS is suppressed, PEB component shows obvious influence on PEH crystallization, PEB is thought to be partially included into PEH lamellar stacks and PEH-PEB co-crystallization is unlikely, however, possible. Optical microscopy was used to monitor crystal nucleation and growth rates in PEH and H50, providing complementary information about the effect of temperature on LLPS and crystallization. Real-space lamellar morphologies in PEH and H50 were characterized by atomic force microscopy (AFM), PEH exhibited sheaf-like spherulites while H50 exhibited hedrites. Overall, the competition between LLPS and crystallization in H50 blend influences the structural and morphological development. Controlling the interplay between LLPS and crystallization of PEH/PEB blends, it is possible to control the structure and morphology as practically needed.     

Thermal and mechanical properties of epoxidized natural rubber modified epoxy matrices

Two sets (A and B) of bisphenol A–diglycidyl ether (DGEBA) based epoxy resin formulations were modified with epoxidized natural rubber (ENR 50) and its liquid version (LENR 50), and cured with amino propoxylate initiator/accelerator at ambient temperatures. The ENR 50 loading range was 1.6–5.9 wt%. Both sets could be loaded up to 12 wt% with LENR 50. Significant improvements in tensile toughness and impact toughness could only be observed for set A formulations. At the maximum LENR 50 loading achieved, the improvement in tensile toughness is 250% in comparison with that of the neat formulation; that for impact toughness is 125%. Differential scanning calorimetry reveals multiple transitions, characteristic of these systems. Scanning electron micrographs of fractured surfaces show uniform rubber dispersions in the submicrometre size range. At the loading levels used, LENR 50 particle dispersions fall within the range of 0.33–0.47 µm in size; those of ENR 50 are 0.48–0.67 µm in average size. Improvements in toughness are similar for both versions of epoxidized natural rubber. For both LENR 50 and ENR 50 modified epoxy systems, the extremes of 0.80 (set A) and 1.95 (set B) in glycidyl ether/reactive hydrogen molar ratios considered show distinct failure mechanisms, that of ductile failure with yielding in the former and brittle failure in the latter, irrespective of reactive diluent content. © 1999 Society of Chemical Industry     

Electrical and Magnetic Properties of Iron-Nickel Sulfide Ceramics

Solid solutions of (Fe,Ni)S were prepared by the metal oxide-carbon disulfide reaction sintering method. These ceramics have the hexagonal NiAs structure, and their lattice parameters depend on the Fe-Ni ratio. The magnetization of these ceramics reduces with decreasing Fe content between 100/0 (Fe/Ni) and 50/50, increases between 50/50 and 40/60, and decreases again between 40/60 and 0/100. The electrical resistivity reduces uniformly with decreasing Fe content of the ceramics.     

Preparation and characterization of polyhydroxybutyrate‐co‐hydroxyvalerate/silk fibroin nanofibrous scaffolds for skin tissue engineering

Nanofibrous scaffolds were obtained by co‐electrospinning poly (3‐hydroxybuty‐rate‐co‐3‐hydroxyvalerate) (PHBV) and fibroin regenerated from silk in different proportions using 1,1,1,3,3,3‐hexafluoro‐2‐isopropanol (HFIP) as solvent. Field emission scanning electron microscope (FESEM) investigation showed that the fiber diameters of the nanofibrous scaffolds ranged from 190 to 460 nm. X‐ray diffraction (XRD) and Fourier transform infrared spectroscopy analysis (FT‐IR) showed that the main structure of silk fibroin (SF) in the nanofibrous scaffold was β‐sheet. Compared to the PHBV nanofibrous scaffold, the surface hydrophilicity and water‐uptake capability of the PHBV/SF nanofibrous scaffold with 50/50 were improved. The results of cell adhesion experiment showed that the fibroblasts adhered more to the PHBV/SF nanofibrous scaffold with 50/50 than the pure PHBV nanofibrous scaffold. The proliferation of fibroblast on the PHBV/SF nanofibrous scaffold with 50/50 was higher than that on the pure PHBV nanofibrous scaffold. Our results indicated that the PHBV/SF nanofibrous scaffold with 50/50 may be a better candidate for biomedical applications such as skin tissue engineering and wound dressing. POLYM. ENG. SCI., 55:907–916, 2015. © 2014 Society of Plastics Engineers     

Influence of blend composition on the physical,flame retardancy,dielectric, aging,and solvent resistance properties of poly[ethylene(vinyl acetate)] and polychloroprene

Poly[ethylene(vinyl acetate)] (EVAc) has been blended with polychloroprene (CR) to develop a compound for application in the cable industry. Physical, flame retardancy, dielectric, and solvent resistance properties have been investigated for the blends. On air and brine aging, the tensile properties for 50/50 blend remains almost unchanged, though retention in tensile properties is maximum for CR in solvent aging and for EVAc in air aging. 50/50 blend shows substantially lower set and hardness compared to EVAc. The limiting oxygen index of 50/50 blend is found to be higher compared to EVAc, which indicates sufficient inflammable capability of 50/50 blend in atmospheric air. A substantially lower dielectric constant, conductivity with good physical properties, and inflammability of 50/50 blend suggests its suitability for use as a cable sheathing compound. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 551–556, 1999     

High-strength,high-modulus fibers from hydrazide polymers and copolymers

A polyhydrazide was prepared from terephthaldihydrazide (TDH) and terephthaloyl chloride (TCl) and copolyhydrazides from oxalicdihydrazide (ODH) and from TCl with a 50:50 molar mixture of ODH and TDH. The 50:50 copolymer gave superior spinning performance and fiber properties and was studied extensively as a candidate for tire cords. The best yarn tensile properties were 21.6 gpd (grams/denier) tenacity, 6% elongation, and 443 gpd modulus. Temperature resistance and creep resistance were good, while the resistance to uv light was only fair. Stability in rubber and adhesion to rubber were good. In radial tires built with equal-strength belts, mileage from tires having the copolymer cord in the belts was equal to that of steel-belted tires.     

Synthesis and evaluation of 3-phenylpyrazolo[3,4-d]pyrimidine-peptide conjugates as Src kinase inhibitors

3-Phenylpyrazolo[3,4-d]pyrimidine (PhPP) derivatives substituted with an alkyl or aryl carboxylic acid at the N1-endocyclic amine, such as PhPP-CH(2)COOH (IC(50)=250 microM), and peptides Ac-CIYKYY (IC(50)=400 microM) and Ac-YIYGSFK (IC(50)=570 microM) were weak inhibitors of polyE(4)Y phosphorylation by active c-Src. A series of PhPP-peptide conjugates were synthesized using PhPP as an ATP mimic and CIYKYY or YIYGSFK as a peptide substrate to improve the inhibitory potency against active c-Src kinase. PhPP derivatives were attached to the N terminus or the side chain of amino acids in the peptide template. Two N-terminal substituted conjugates, PhPP-CH(2)CO-CIYKYY (IC(50)=0.38 microM) and PhPP-CH(2)CO-YIYGSFK (IC(50)=2.7 microM), inhibited the polyE(4)Y phosphorylation by active c-Src significantly higher than that of the parent compounds. The conjugation of PhPP with the peptides produced a synergistic inhibition effect possibly through creation of favorable interactions between the conjugate and the kinase domain as shown by molecular modeling studies.     

Alginate and carboxymethyl cellulose in monolayer and bilayer films as wound dressings: Effect of the polymer ratio

In this study, we investigated different proportions of alginate and carboxymethyl cellulose (CMC) biopolymers in the formulation of films to act as wound dressings. With the casting method, monolayer and bilayer (BL) films were produced with alginate/CMC proportions (weight percentages) of 0:100 (0A), 25:75 (25A), 50:50 (50A), 75:25 (75A), and 100:0 (100A). Thin, homogeneous, and continuous films were obtained with glycerol and crosslinking with CaCl₂. The fluid uptake, film stability, and morphological, mechanical, thermal, and barrier properties were evaluated. A general tendency of the film characteristics was visualized: 50A had intermediary characteristics from both polymers; although the liquid behavior characteristics were improved with increasing CMC content, the mechanical properties worsened. When compared to the monolayer film (50A), the BL film 50A–BL demonstrated a better water vapor transmission rate. In this study, we demonstrated the necessity of varying the polymer concentrations to assist in the production of wound dressings. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 46941.     

Pb-TKX-50燃烧催化剂的合成及热分解性能

以二氯乙二肟、二甲基甲酰胺、叠氮化钠、盐酸羟胺和硝酸铅等为原料,合成了1,1-二羟基-5,5′-联四唑羟胺铅盐(Pb-TKX-50)燃烧催化剂,研究了Pb-TKX-50对推进剂机械感度的影响以及与推进剂组分的相容性;利用差示扫描量热法和热重法研究了Pb-TKX-50在不同升温速率下的热分解过程,计算其表观活化能(E K和E O)和指前因子(A K),得到其热分解动力学参数、热分解机理函数、热爆炸温度和热力学性质。结果表明,在推进剂配方中加入Pb-TKX-50燃烧催化剂,可以改善其撞击感度和摩擦感度,且与推进剂组分的相容性良好;Pb-TKX-50的主峰分解温度相对于TKX-50的主峰分解温度显著提高,说明其热稳定性显著提高。Ozawa法和Kissinger法得到Pb-TKX-50的表观活化能分别为181.45 kJ/mol和182.49 kJ/mol,且热分解过程符合Avrami-Erofeev方程;Pb-TKX-50的自加速分解温度和爆炸临界温度分别为500.53 K和544.33 K,表明其热稳定性良好;Pb-TKX-50催化剂的热分解自由能(ΔG^≠)为158.87 kJ/mol,活化焓(ΔH^≠)为187.03 kJ/mol,活化熵(ΔS≠)为52.98 kJ/mol。     

Comparative study on foaming and foam stability of multiple mixed systems of fluorocarbon,hydrocarbon, and amino acid surfactants

This study focuses on the effect of amino acid surfactant (sodium lauroyl glutamate [SLG]) on foam properties of a mixture of fluorocarbon (FS-50) and hydrocarbon (APG0810) surfactants. The molecular interactions, foamability, and foam stability of the surfactant solutions are systematically studied. The results show that SLG has stronger ability to lower surface tension of water compared to APG0810, but worse that than FS-50, and to adsorb onto gas/liquid interface in mixed solutions with FS-50 compared to APG0810. The addition of SLG increased foamability of APG0810/FS-50 mixed solution, and decelerated foam drainage and coarsening of individual APG0810, individual FS-50, and mixture of APG0810/FS-50 solutions. The mixture of SLG/FS-50 exhibited the higher foamability and foam stability than the frequently used critical component of the new developed AFFF, the mixture of APG0810/FS-50. This study can provide guidance for the scientific application of amino acid surfactants in the development of environmentally friendly firefighting foams.     

Antiproliferative and Proapoptotic Activities of Methanolic Extracts from Ligustrum vulgare L. as an Individual Treatment and in Combination with Palladium Complex

The aim of this study is to examine the growth inhibitory effects of methanolic leaf and fruit extracts of L. vulgare on HCT-116 cells over different time periods and their synergistic effect with a Pd(apox) complex. The antiproliferative activity of plant extracts alone or in combination with the Pd(apox) complex was determined using MTT cell viability assay, where the IC(50) value was used as a parameter of cytotoxicity. Results show that antiproliferative effects of L. vulgare extracts increase with extension of exposure time, with decreasing IC(50) values, except for 72 h where the IC(50) values for methanolic leaf extract were lower than for the fruit extract. The Pd(apox) complex alone had a weak antiproliferative effect, but combination with L. vulgare extracts caused stronger effects with lower IC(50) values than with L. vulgare extracts alone. The type of cell death was explored by fluorescence microscopy using the acridin orange/ethidium bromide method. Treatments with plant extracts caused typical apoptotic morphological changes in HCT-116 cells and co-treatments with Pd(apox) complex caused higher levels of apoptotic cells than treatment with plant extracts alone. The results indicate that L. vulgare is a considerable source of natural bioactive substances with antiproliferative activity on HCT-116 cells and which have a substantial synergistic effect with the Pd(apox) complex.     

Preparation,Characterization, and Separation Performances of Novel Surface Modified LbL Composite Membranes from Polyelectrolyte Blends and MWCNT

Here, it was aimed to modify the surface of NF90 with layer by layer (LbL) blended poly(allylamine hydrochloride) (PAH)-chitosan (CHI) and poly(acrylic acid) (PAA) with/without functionalized multiwalled carbon nanotube (fMWCNT) for reverse-osmosis applications. Using Quartz Crystal Microbalance Dissipation monitoring, it was observed that PAH-CHI/PAA LbL films grew linearly after a few bilayers and no LbL film degradation occurred during synthetic seawater treatment. Thermal degradation of all LbL blended membranes was similar. NF90 had a heterogeneous surface while the surface of LbL blend membranes exhibited some agglomerations due to the polyelectrolyte (PE) complex formation and fibrillary appearance depending on the use of fMWCNT. [(PAH50-CHI50/(PAA-fMWCNT)]₃₀ indicated the highest flux with 14.5 L m² h⁻¹ at 40 bar. The sodium and chlorine ion rejections were 75% and 87%, respectively, for the same membrane. The use of fMWCNT led to a significant enhancement in flux with a slight decay in ion rejections. On the other hand, chlorine ion rejection of [(PAH50-CHI50/(PAA-fMWCNT)]₃₀ decreased by 25% at 40 bar while 60 and 90 bilayers of [(PAH50-CHI50/(PAA-fMWCNT)] disintegrated after NaOCl treatment. Briefly, the flux and ion rejections of the LbL blended membranes can be controlled depending on the use of fMWCNT and different PE couples without multilayer decomposition against synthetic seawater. POLYM. ENG. SCI., 60: 341–351, 2019. © 2019 Society of Plastics Engineers     

Tensile,Tear and Swelling Properties of ENR 50/SBR Blend

Abstract

Tensile strength, tear strength and swell index of epoxidized natural rubber (ENR 50) blended with styrene-butadiene rubber (SBR) was studied. The blend ratio was varied from 0–100% of ENR 50. Accelerated-sulfur conventional vulcanization system was used throughout the study. Tensile property and tear strength of the blend were determined by Monsanto Tensometer (Model T10) and toluene was used as the solvent in the swell index experiment. Results show that tensile strength and elongation at break increases with ENR 50 up to about 70% ENR 50, whereas for the tear strength, it increases steadily with increasing ENR 50, an observation which is attributed to strain-induced crystallization of ENR. Similar behavior was observed with the aged sample though its absolute value is lower than that of the unaged sample. As for the swell index, it decreases gradually with increasing ENR indicating the increase in polarity of the blend as the blend ratio of ENR 50 is increased.     

Molecular dynamics and dissipative particle dynamics simulations for the miscibility of poly(ethylene oxide)/poly(vinyl chloride) blends

The miscibility of poly(ethylene oxide) (PEO)/poly(vinyl chloride) (PVC) blends are investigated by atomistic molecular dynamics and mesoscale dissipative dynamics simulations. The specific volumes of three PEO/PVC blends (with weight ratio at 70/30, 50/50 and 30/70) as well as pure PEO and PVC are examined as a function of temperature. The glass transition temperatures are estimated to be 251, 268, 280, 313 and 350 K for pure PEO, PEO/PVC 70/30, 50/50, 30/70 and pure PVC. Among different energy contributions, the torsion and van der Waals energies exhibit pronounced kinks versus temperature. The Flory-Huggins parameters determined from the cohesive energy densities and the radial distribution functions of the inter-molecular atoms suggest that PEO/PVC 70/30 and 30/70 blends are more miscible than 50/50 blend. This is further supported by the morphologies of PEO/PVC blends, in which the 50/50 blend exhibits segregated domains implying a weak phase separation. Hydrogen bonds are found to form between O atoms of PEO and H atoms of PVC, with a larger degree in PEO/PVC 70/30 and 30/70 blends than in 50/50 blend. The addition of PVC into PEO suppresses the mobility of PEO chains, which is consistent with the experiment observation of decreased crystallization rate as well as crystallization temperature of PEO.     

Dietary analysis and patterns of nutritional supplement use in normal and age-related macular disease affected subjects: a prospective cross-sectional study

Background  

Poor diet is thought to be a risk factor for many diseases, including age-related macular disease (ARMD), which is the leading cause of blind registration in those aged over 60 years in the developed world. The aims of this study were 1) to evaluate the dietary food intake of three subject groups: participants under the age of 50 years without ARMD (U50), participants over the age of 50 years without ARMD (O50), and participants with ARMD (AMD), and 2) to obtain information on nutritional supplement usage.     

Fabrication and characterization of epoxylated zwitterionic copolymergrafted silica nanoparticle as a new support for lipase immobilization

Our previous work proved that the thermal stability of Candida rugosa lipase (CRL) immobilized on zwitterionic polymer (poly(carboxybetaine methacrylate)) grafted silica nanoparticle (SNP) was much higher than that on poly(glycidyl methecrylate) (pGMA) grafted SNP, while the latter showed significantly increased activity. Inspired by the research, we have herein proposed to synthesize copolymers of zwitterionic sulfobetaine methacrylate (SBMA) and GMA for CRL immobilization. The copolymers were grafted onto SNP surface at three GMA/ SBMA (G/S) molar ratios (G100/S0, G50/S50, G10/S90), followed by the covalent coupling of CRL to the surface copolymers. The immobilized CRLs on the corresponding supports were denoted as p(G100-S0)-CRL, p(G50-S50)-CRL and p(G10-S90)-CRL. The enzyme loading increased with the increase of GMA content in the copolymer, while the activity varied with the grafted copolymer composition. Kinetic study proved the improvement of enzyme-substrate affinity after immobilization. In comparison to p(G100-S0)-CRL, p(G50-S50)-CRL and p (G10-S90)-CRL presented remarkably enhanced thermal stability and pH tolerance, and p(G10-S90)-CRL showed the highest stability. These results suggest that the copolymer design is promising for development as a versatile platform for enzyme immobilization.