两种海洋微藻硝酸还原酶活性测定方法的比较研究

对6种常见海洋微藻的硝酸还原酶活性测定方法进行了初步研究。确立了离体法和活体法的提取(振荡)时间及酶促反应时间,分别为:5 min,30 min(离体法)和6 min,10 min(活体法),并对2种方法进行了对比。结果表明:在本文条件下,离体法较活体法更适于进行塔玛亚历山大藻(Alexandrium tamarense)、强壮前沟藻(Amphidinium carterae)、中肋骨条藻(Skeletonema costatum)、新月菱形藻(Nitzchia closterium)和旋链角毛藻(Chaetoceros curvisetus)的硝酸还原酶活性的测定;活体法更适于东海原甲藻(Prorocentrum donghainase)硝酸还原酶活性的测定。

热带海草海菖蒲不同组织中硝酸还原酶活力的研究

利用活体法研究了海南陵水新村湾热带海草海菖蒲不同组织中硝酸还原酶活力以及酶促反应条件因子pH、温度和KNO3浓度对酶活力的影响;pH设3个水平(7,8,9),温度(20～40℃)和KNO3(50～250mmol·L-1)浓度各5个水平。研究表明:酶促反应温度和KNO3浓度对酶活力有显著影响,而pH对酶活力没有影响;海菖蒲的最佳酶促反应条件为:100mmol·L-1KNO3,0.5mmol·L-1Na-EDTA、磷酸缓冲液(pH=8.0)、10mmol·L-1葡萄糖和w=0.5%的正丙醇;温度为30℃。在最佳酶促反应条件下,海菖蒲叶、根和茎的鲜质量组织中硝酸还原酶活力大小分别为:1.01,0.08,0.001μmol.g-1.h-1。

Investigation of bioactivity and biodegradability of Mg-bioceramic implants:An in vitro study for biomedical applications

In this study,Mg-based composites,by the addition of ZnO,Ca_(2)ZnSi_(2)O_(7),Ca_(2)MgSi_(2)O_(7),and CaSiO_(3)as bioactive agents,were fabricated using friction stir processing.The microstructure and in vitro assessment of bioactivity,biodegradation rate,and corrosion behavior of the resultant composites were investigated in simulated body fluid(SBF).The results showed that during the immersion of composites in SBF for 28 d,due to the release of Ca^(2+)and PO_(4)^(3-)ions,hydroxyapatite(HA)crystals with cauliflower shaped morphology were deposited on the surface of composites,confirming good bioactivity of composites.In addition,due to the uniform distribution of bioceramic powders throughout Mg matrix,grain refinement of the Mg matrix,and uniform redistribution of secondary phase particles,the polarization resistance increased,and the biodegradation rate of composites significantly reduced compared to monolithic Mg matrix.The polarization corrosion resistance of Mg-ZnO increased from 0.216 to 2.499 kΩ/cm^(2)compared to monolithic Mg alloy.Additionally,Mg-ZnO composite with the weight loss of 0.0217 g after 28 d immersion showed lower weight loss compared to other samples with increasing immersion time.Moreover,Mg-ZnO composite with the biodegradation rate of 37.71 mm/a exhibited lower biodegradation rate compared to other samples with increasing immersion time.

Reheating and thixoforging of ZK60+RE alloy deformed by ECAE

The two-pass equal channel angular extrusion (ECAE) process was introduced into strain-induced melt activation (SIMA) to predeform a ZK60 alloy with rare earth (RE) addition. Microstructure evolution of ECAE-formed ZK60+RE alloy during reheating was investigated. Furthermore, tensile properties of thixoforged components were determined. The results show that the SIMA process can produce ideal microstructures, and spheroidized solid particles with little entrapped liquid can be obtained. With prolonging holding time, the size of solid particles increases and the degree of spheroidization is improved. The tensile properties of the thixoforged ZK60+RE samples are close to those of two-pass ECAE-formed samples.

Ultra-Cut biopsy guided by ultrasonography for liver lesions：experience of 392 clinical cases

We conducted a retrospective study of the accuracy of liver biopsies in 392 patients with liver lesions. Postbiopsy diagnosis was 297 cases of primary liver cancers, 79 cases of secondary malignant tumors, 2 cases of non Hodgkin's lymphoma, 10 cases of focal nodular hyperplasia, 2 cases of chronic inflammation, 1 tuberculosis case and 1 schistosomiasis case. Biopsy provided histological diagnosis in 100% of cases, sensibility and specificity of Ultra Cut biopsy was 98.95% and 100% for the diagnosis of malignancy respectively; positive predictive value, 100%; negative predictive value, 71.43%; and accuracy, 98.98%. We identified no major procedure related complications despite the presence of thrombocytopenia in 37.5% of cases. Pain was the only reported adverse effect of liver biopsy (10.97%), and 11 patients required analgesics. We concluded that Ultra Cut liver biopsy was a safe and effective technique, and was invaluable in the investigation and management of patients with liver lesions.

Gastric stimulation for weight loss

The prevalence of obesity is growing to epidemic proportions,and there is clearly a need for minimally invasive therapies with few adverse effects that allow for sustained weight loss.Behavior and lifestyle therapy are safe treatments for obesity in the short term,but the durability of the weight loss is limited.Although promising obesity drugs are in development,the currently available drugs lack efficacy or have unacceptable side effects.Surgery leads to long-term weight loss,but it is associated with morbidity and mortality.Gastric electrical stimulation(GES) has received increasing attention as a potential tool for treating obesity and gastrointestinal dysmotility disorders.GES is a promising,minimally invasive,safe,and effective method for treating obesity.External gastric pacing is aimed at alteration of the motility of the gastrointestinal tract in a way that will alter absorption due to alteration of transit time.In addition,data from animal models and preliminary data from human trials suggest a role for the gut-brain axis in the mechanism of GES.This may involve alteration of secretion of hormones associated with hunger or satiety.Patient selection for gastric stimulation therapy seems to be an important determinant of the treatment's outcome.Here,we review the current status,potential mechanisms of action,and possible future applications of gastric stimulation for obesity.

Prediction of esophageal and gastric histology by macroscopic diagnosis during upper endoscopy in pediatric celiac disease

AIMTo determine the sensitivity of macroscopic appearance for predicting histological diagnosis at sites other than duodenum in pediatric celiac disease (CD).METHODSEndoscopic and histologic findings in pediatric patients undergoing upper endoscopy for first-time diagnosis of CD at Stollery Children’s Hospital from 2010-2012 were retrospectively reviewed.RESULTSClinical charts from 140 patients were reviewed. Esophageal and gastric biopsies were taken in 54.3% and 77.9% of patients, respectively. Endoscopic appearance was normal in the esophagus and stomach in 75% and 86.2%. Endoscopic esophageal diagnoses were eosinophilic esophagitis (EE) (11.8%), esophagitis (7.9%), glycogenic acanthosis (1.3%) and non-specific abnormalities (3.9%). Endoscopic gastric diagnoses were gastritis (8.3%), pancreatic rest (0.9%), and non-specific abnormalities (4.6%). Histology was normal in 76.3% of esophageal and 87.2% of gastric specimens. Abnormal esophageal histology was EE (10.5%), esophagitis (10.5%), glycogenic acanthosis (1.3%) and non-specific (1.3%). Gastritis was reported in 12.8% of specimens. Sensitivity and specificity of normal endoscopy for predicting normal esophageal histology was 86.2% and 61.1%, and for normal gastric histology was 87.4% and 21.4%.CONCLUSIONIn the absence of macroscopic abnormalities, routine esophageal and gastric biopsy during endoscopy for pediatric CD does not identify major pathologies. These findings have cost and time saving implications for clinical practice.

The Oral Language as the Primary Medium Among Men

Nowadays, language has gained great importance due to mass media which allows men to interact with other people anytime and anywhere. Some issues arise： Do media change the way we communicate？ Are there any means in particular that can help people to communicate better？ This paper finds the route for individuals to communicate better, understand each other, and promote values of both our society and culture demand. Three main issues are presented to reach this goal： Firstly, the platonic theory about names, if things are called by convention or by its nature. Secondly, three methods by which these names are used： the grammar, the rhetoric, and the dialectics. Lastly, how orality is a fundamental means for human communication. Each of these subjects will become arguments to support that dialogue is the most suitable and human way for men to communicate, because it gives the necessary tools to man to build himself according to his nature, that is to say, the search for the good and the rational perfection.

Catalytic methanation of syngas over Ni-based catalysts with different supports

Co-precipitation method was selected for the preparation of Ni/Al_2O_3, Ni/ZrO_2 and Ni/CeO_2 catalysts, and their performances in methanation were investigated in this study. The structure and surface properties of these catalysts were characterized by BET, XRD, H_2-TPD, TEM and H_2-TPR. The results showed that the catalytic activity at low temperature followed the order: Ni/Al_2O_3>Ni/ZrO_2>Ni/CeO_2. Ni/Al_2O_3 catalyst presented the best catalytic performance with the highest CH_4 selectivity of 94.5%. The characterization results indicated that the dispersion of the active component Ni was the main factor affecting the catalytic activity and the one with higher dispersion gave better performance.

Optimization of conjugated linoleic acid triglycerides via enzymatic esterification in no-solvent system

We compared four esterifiable enzymes. The lipase Novozym 435 possessed the highest activity for the conjugated linoleic acid esterification during the synthesis of triglycerides. The triglycerides were synthesized by esterification of glycerol and conjugated linoleic acid （CLA） in a no-solvent system using lipase catalysis. We investigated the effects of temperature, enzyme concentration, water content, and time on esterification. Enzyme and water concentrations of up to 1% of the total reaction volume and a system temperature of 60℃ proved optimal for esterification. Similarly, when the esterification was carried out for 24 h, the reaction ratio improved to 94.11%. The esterification rate of the rotating screen basket remained high （87.28%） when the enzyme was re-used for the 5th time. We evaluated the substrate selectivity of lipase （NOVO 435） and determined that this lipase prefers the 10,12-octadacadienoic acid to the 9,11-octadecadienoic acid.

Oxygen Transfer and Hydrodynamics in a Flexible Fibre Biofilm Reactor for Wastewater Treatment

A flexible fibre biofilm reactor was developed for treatment of organic wastewaters.The hydrodynamic characteristics and mass transfer coefficients of oxygen were studied and compared with those of the conventional activated sludge processes.Tracer experiments were performed to obtain the residence time distributions of the reactors.The results indicated that both reactors could be treated as mixed flow reactors.The effects of flow rates of water and air on the overall mass transfer coefficient of oxygen were investigated,and the correlations between the mass transfer coefficient and the ratio of flow rates were obtained.Compared to the conventional activated sludge reactor,the mass transfer coefficients in the flexible fibre reactor were similar to but slightly lower,and less sensitive to the variation in the ratio of flow rates.It indicated that the fibre packing in the reactor hindered the oxygen transfer to some extent.

Feasibility study on the integration of urban and rural minimum living security system based on SWOT model

This paper uses SWOT analysis, feasibility analysis of integration of urban and rural residents in China, including the overall analysis of the urban and rural integration China internal conditions, mainly for its overall advantages and disadvantages are analyzed; and the external environment, the system is mainly to raise the opportunities and threats were analyzed; in these. The external conditions are analyzed based on the construction of SWOT strategic matrix, found the advantages and disadvantages of the reform process of the integration of urban and rural subsistence allowances system in coexist, opportunities outweigh the challenges, so China＇s overall urban and rural integration construction is feasible.

In Vitro Biossay for Assessing Estrogenic Activity of Sewage Treatment Works

The estrogenic activity of influents and effluents of five municipal sewage treatment works （STWs） in Nanjing was investigated. The water samples were enriched by solid phase extraction, then eluted with different polar solvents, and f＇mally three fractionated extracts were obtained. Estrogen receptor recombinant yeast screen was used to evaluate the estrogenic activity of individual fractionated extracts and their mixture. The results show that the influents and effluents of the two STWs mainly receiving industrial wastewater have no obvious estrogenic activity, and the water samples from the other three STWs mainly receiving domestic wastewater show different degrees of estrogenic activity. The total estrogenic concentration ranged from 171. 52 ng/L EEQ （E2 - equivalent concentration） to 1 008.37 ng/L EEQ in the influents, and from ND （not detected） to 36.3 ng/L EEQ in the effluents. By comparing the results of different fractionated extracts, the methanol and dichloromethane extracts of the water samples show higher estrogenic activity, while the hexane extracts very low. The （xeno）estrogens from domestic wastewater could be removed obviously by activated sludge treatment units. However, the effluents of STWs in Nanjing still have chemical contaminants capable of binding to estrogen receptors.

Dolphin swarm algorithm

By adopting the distributed problem-solving strategy, swarm intelligence algorithms have been successfully applied to many optimization problems that are difficult to deal with using traditional methods. At present, there are many well-implemented algorithms, such as particle swarm optimization, genetic algorithm, artificial bee colony algorithm, and ant colony optimization. These algorithms have already shown favorable performances. However, with the objects becoming increasingly complex, it is becoming gradually more difficult for these algorithms to meet human＇s demand in terms of accuracy and time. Designing a new algorithm to seek better solutions for optimization problems is becoming increasingly essential. Dolphins have many noteworthy biological characteristics and living habits such as echolocation, information exchanges, cooperation, and division of labor. Combining these biological characteristics and living habits with swarm intelligence and bringing them into optimization problems, we propose a brand new algorithm named the ‘dolphin swarm algorithm＇ in this paper. We also provide the definitions of the algorithm and specific descriptions of the four pivotal phases in the algorithm, which are the search phase, call phase, reception phase, and predation phase. Ten benchmark functions with different properties are tested using the dolphin swarm algorithm, particle swarm optimization, genetic algorithm, and artificial bee colony algorithm. The convergence rates and benchmark function results of these four algorithms are compared to testify the effect of the dolphin swarm algorithm. The results show that in most cases, the dolphin swarm algorithm performs better. The dolphin swarm algorithm possesses some great features, such as first-slow-then-fast convergence, periodic convergence, local-optimum-free, and no specific demand on benchmark functions. Moreover, the dolphin swarm algorithm is particularly appropriate to optimization problems, with more calls of fitness functions and fewer individuals.

Behavior of gold-enhanced electrocatalytic performance of NiPtAu hollow nanocrystals for alkaline methanol oxidation

The Pt-based catalyst tends to be poisoned by carbon monoxide(CO)-like intermediates produced in fuel cell reactions,which seriously deteriorates its catalytic performance.Herein,noble metal Au with the capacity of resistance to CO-like intermediates poisoning was employed to construct multi-element Pt-based catalysts.Two trimetallic NiPtAu hollow nanocrystals(HNCs)with different surface Au contents were synthesized to explore the role of Au in electrocatalysis for alkaline methanol oxidation reaction(MOR).The trimetallic NiPtAu-SRAu HNCs catalyst with the relative rich Au content(15.17 at%)on surface exhibits a much lower CO oxidation peak potential than the other HNCs counterpart and 20 wt%Pt/C,which indicates the more exceptional CO-resisting performance.Besides,the MOR specific activity of NiPtAu-SRAu HNCs(31.52 mA cm^−2)is 7 times higher than that of 20wt%Pt/C(4.50 mA cm^−2).This enhancement in catalytic activity as well as anti-CO poisoning capability for NiPtAu-SRAu HNCs can be mainly ascribed to the weakened CO adsorption due to the exposure of Au atoms on NiPt surface evidenced by the experimental data and density functional theory calculations.This study not only investigates the role of Au in MOR catalysis but also could be helpful for designing and optimizing the electrocatalysts for high-active and robust fuel cell applications.

Ambient synthesis, characterization, and electrochemical activity of LiFePO4 nanomaterials derived from iron phosphate intermediates

LiFePO4 materials have become increasingly popular as a cathode material due to the many benefits they possess including thermal stability, durability, low cost, and long life span. Nevertheless, to broaden the general appeal of this material for practical electrochemical applications, it would be useful to develop a relatively mild, reasonably simple synthesis method of this cathode material. Herein, we describe a generalizable, 2-step methodology of sustainably synthesizing LiFePO4 by incorporating a template-based, ambient, surfactantless, seedless, U-tube protocol in order to generate size and morphologically tailored, crystalline, phase-pure nanowires. The purity, composition, crystallinity, and intrinsic quality of these wires were systematically assessed using transmission electron microscopy （TEM）, high-resolution TEM （HRTEM）, scanning electron microscopy （SEM）, X-ray diffraction （XRD）, selected area electron diffraction （SAED）, energy dispersive analysis of X-rays （EDAX）, and high-resolution synchrotron XRD. From these techniques, we were able to determine that there is an absence of any obvious defects present in our wires, supporting the viability of our synthetic approach. Electrochemical analysis was also employed to assess their electrochemical activity. Although our nanowires do not contain any noticeable impurities, we attribute their less than optimal electrochemical rigor to differences in the chemical bonding between our LiFePO4 nanowires and their bulk-like counterparts. Specifically, we demonstrate for the first time experimentally that the Fe-O3 chemical bond plays an important role in determining the overall conductivity of the material, an assertion which is further supported by recent ＂first-principles＂ calculations. Nonetheless, our ambient, solution-based synthesis technique is capable of generating highly crystalline and phase-pure energy-storage-relevant nanowires that can be tailored so as to fabricate different sized materials of reproducible, reliable morphology.

Isothermal crystallization in Ce_(70)Ga_6Cu_(24) bulk metallic glass

The isothermal crystallization behaviors in a newly developed CeGaCu bulk metallic glass have been investigated through the classic differential scanning calorimeter （DSC） method. It is found that the apparent activation energy （Ea） strongly depends on the fraction （x） of isothermal crystallization. Johnson-Mehl-Avrami （JMA） formula was used to analyze the mechanism of crystallization and the obtained Avrami exponent （n） was discovered to show an obvious correlation with the crystallization fraction x. With the help of the relation between Ea and n, the nucleation and growth activation energies, En and Eg, were estimated to be 214-304 kJ/mol and 91 kJ/mol, respectively. This result suggests that the main energy barrier against crystallization in the present glass should be the nucleation of nucleates, rather than the growth of crystals. Such a large E, is also believed to be responsible for the good glass forming ability of the CeGaCu alloy.