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Biogenesis of antibacterial silver nanoparticles using the endophytic bacterium Bacillus cereus isolated from Garcinia xanthochymus

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Asian Pacific Journal of Tropical Biomedicine 2012年第12期2卷 953-959页

作者： Swetha Sunkar c Valli Nachiyar Department of Biotechnology Sathyabama University

Objective:To synthesize the ecofriendly nanoparticles,which is viewed as an alternative to the chemical method which initiated the use of microbes like bacteria and fungi in their ***:The current study uses the endophytic bacterium Bacillus cereus isolated from the Garcinia xanthochymus to synthesize the silver nanoparticles(AgNPs).The AgNPs were synthesized by reduction of silver nitrate solution by the endophytic bacterium after incubation for 3-5 d at room *** synthesis was initially observed by colour change from pale white to brown which was confirmed by UV-Vis *** AgNPs were further characterized using FTIR,SEM-EDX and TEM ***:The synthesized nanoparticles were found to he spherical with the size in the range of 20-40 nm which showed a slight *** energy-dispersive spectra of the nanoparticle dispersion confirmed the presence of elemental *** AgNPs were found to have antibacterial activity against a few pathogenic bacteria like Escherichia coli,Pseudomonas aeruginosa,Staphylococcus aureus,Salmonella typhi and klebsiella ***:The endophytic bacteria identified as Bacillus cereus was able to synthesize silver nanoparticles with potential antibacterial activity.

关键词： Endophytic bacteria Bacillus cereus Silver nanoparticles UV-Vis spectra SEM TEM Antibacterial activity

Fish Swim Bladder-Derived Porous carbon for Defluoridation at Potable Water pH

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Advances in chemical Engineering and Science 2016年第4期6卷 500-514页

作者： John karuga Yusufu A. c. Jande Hee T. kim cecil k. king’ondu Department of Materials and Energy Science and Engineering Nelson Mandela African Institution of Science and Technology Arusha Tanzania Department of chemical Engineering Hanyang University Seoul Republic of South Korea Department of chemistry South Eastern Kenya University Kitui Kenya

The levels of fluoride in various ground water sources in East Africa are above the World Health Organization upper limit of 1.5 mg/L. Research on diverse defluoridation technologies has proven that adsorption stands out as an affordable, efficient, and facile technology. Fish swim bladder-derived porous carbon (FBPc) activated by kOH and surface oxidized by nitric acid was successfully investigated as an adsorbent for defluoridation at portable water pH. The FBPc was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS). Batch methods were used to study physiochemical parameters viz., initial fluoride concentration, temperature, adsorbate dosage, contact time and pH. Freundlich, Temkin, Langmuir and Dubinin-Radushkevich isotherms were plotted and analyzed to understand the adsorption process. Bangham, Weber Morris, pseudo first and second-order models were used to elucidate the kinetics of adsorption. Optimal conditions for fluoride removal were found to be: pH of 6, FBPc adsorbent dose of 5.0 g/L and contact time of 50 min. Flouride adsorption followed pseudo second-order kinetic model and Langmuir isotherm best describes the adsorption process.

关键词： Defluoridation Adsorption Fish Swim Bladder Porous carbon Fluoride

The effect of global warming on beef production in developing countries of the southern hemisphere

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Natural Science 2013年第1期5卷 106-119页

作者： M.M.Scholtz c.McManus k-J.Leeuw H.Louvandini L.Seixas c.B.de Melo A.Theunissen F.W.c.Neser ARc-Animal Production Institute IreneSouth Africa University of the Free State BloemfonteinSouth Africa Insituto Nacional de ciencia e Tecnologia-InformacaoGenetico-Sanitaria da Pecuaria Brasileira Brazil Departamento de Zootecnia Universidade Federal de Rio Grande do SulPorto AlegreBrazil centro de Energia Nuclear na Agricultura Universidade de Sao PauloPiracicabaBrazil Faculdade de Agronomia e Medicina Veterinaria Universidade de BrasiliaBrasiliaBrazil Northern cape Department of Agricultural Land Reform and Rural DevelopmentJan KempdorpSouth Africa

Developing countries from the southern hemisphere will be confronted by the same beef production challenges caused by global warming, because these countries are at the same geographical positions in southern latitudes. Global warming is expected to have a more extreme effect on the southern hemisphere than on other continents and will have a negative effect on the beef production environments in these countries. The negative effects will include high ambient temperatures, nutritional stress and altered patterns of animal diseases. Heat stress in beef cattle on veld/savannah is expected to increase as a result of changing weather patterns on a global and regional scale. This may negatively influence food production from beef cattle for the human food chain. Negative effects of increased temperatures and thus heat stress can include lower reproductive rates and weaning weights. The effect of heat stress can be partly addressed by nutritional strategies, such as replacing rapid fermentable carbohydrates with saturated fatty acids and the feeding of more by-pass protein and dietary electrolytes. Global warming will also alter the distribution pattern of animal diseases and the vectors of some of these diseases. This may even include the spread to South American countries. Likewise the nutritional value of natural pastures may be influenced. The effect of global warming on the quality of pastures will depend on whether the global warming is a result of increased carbon dioxide levels or not. An improved understanding of the adaptation of beef cattle to their production environments is important, but adaptation is complex and thus difficult to measure. Fortunately, several proxy-indicators for adaptation such as reproductive, production and health traits are available. The selection of animals and genotypes that are better adapted to the production system, including heat stress, is possible and should be persuade to ensure sustainable beef production in hotter climates.

关键词： Adaptation Animal diseases Heat Stress Mitigation Strategies Nutritional Stress

cRYSTAL STRUcTURE AND ELEcTROcHEMIcAL PROPERTIES OF Zr(Mn_(1-x)Ni_x)_2(0.40≤x≤0.75) HYDROGEN STORAGE ALLOYS

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Acta Metallurgica Sinica(English Letters) 2001年第1期14卷 56-62页

作者： W.k. Zhang, c.A. Ma, X.G. Yang, H. Huang, Y.Q. Lei and Q.D. Wang (Department of Applied chemistry, Zhejiang University of Technology, Hangzhou 310014, china Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, china) Dept. of Appl. chem. Zhejiang Univ. of Technol. Hangzhou 310014 China

The crystal structure, phase abundance and the electrochemical properties of Zr(Mn1-x Nix)2 (0.40 ≤x≤0.75) alloys were investigated by means of XRD, Rietveld refinement method and electrochemical measurements. The alloys are multiphase. c15 Laves phase occurs as a main phase accompanying with c14 phase and other minor phases, indicating that Ni element is c15-stabilized element for ZrMn2 alloy. The phase abundance and lattice parameters of Laves phase are influenced significantly by Ni substitution. The Zr(Mn0.45 Ni0.55)2 alloy with the highest amount of c15 phase exhibits the maximum electrochemical capacity of 242m Ah/g. c14 phase occurring in Zr-Mn-Ni alloys is beneficial for the electrochemical kinetics of hydride electrodes.

关键词： hydrogen storage alloy crystal structure phase abundance,elec- trochemical property

Regulatory and activated effector T cells in chronic hepatitis c virus: Relation to autoimmunity

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World Journal of Hepatology 2016年第30期8卷 1287-1294页

作者： Hanan Fouad Maissa El Raziky Eman Medhat Hassan Ghada Mahmoud Abdel Aziz Samar k Darweesh Ahmed Reda Sayed Department of Medical Biochemistry Faculty of Medicine Cairo University Department of Pharmacology and Toxicology Faculty of Pharmacy Hail University Department of Hepato-gastroenterology and Tropical Medicine Faculty of Medicine Cairo University Department of Medical Biochemistry Faculty of Medicine Beni Suef University

AIMTo investigate how Tregs are regulated in chronic hepatitis c virus (HcV) patients via assessment of Tregs markers (granzyme 2, cD69 and FoxP3), Teffs markers [TNFRSF4 (OX40), INFG] and cD4, cD25 genes. METHODSA prospective study was conducted on 120 subjects divided into 4 groups: Group I (n = 30) treatment naïve chronic HcV patients; Group II (n = 30) chronic HcV treated with Peg/Riba; Group III (n = 30) chronic HcV associated with non-organ specific autoantibody and Group IV (n = 30) healthy persons as a control group. Tregs and Teffs markers were assessed in peripheral blood mononuclear cells by quantitative real time reverse transcriptase-polymerase chain reaction. RESULTSchronic HcV patients exhibited significant higher levels of both Teffs and Tregs in comparison to healthy control group. Tregs markers were significantly decreased in Peg/Riba treated HcV patients in comparison to treatment naïve HcV group. In HcV patients with antinuclear antibody (ANA) +ve, Tregs markers were significantly decreased in comparison to all other studied groups. Teffs markers were significantly elevated in all HcV groups in comparison to control and in HcV group with ANA +ve in comparison to treatment naïve HcV group. cONcLUSIONElevated Tregs cells in chronic HcV patients dampen both cD4+ and cD8+ autologous T cell immune response. Interferon-α and ribavirin therapy suppress proliferation of Tregs. More significant suppression of Tregs was observed in HcV patients with autoantibodies favoring pathological autoimmune response.

关键词： Autoimmunity T regulatory cells Hepatitis c virus T activator cells Interferon

corrosion of High carbon Steel by Bacteria under Aerobic and Anaerobic conditions

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Materials Sciences and Applications 2019年第3期10卷 227-242页

作者： R. c. Nwokorie c. O. Nweke S. I. Umeh F. c. Ihenetu O. R. Nlemolisa U. N. kemka c. c. Obasi c. I. Nnadi k. H. Uzoho c. c. Ejide Department of Microbiology Federal University of Technology Owerri Nigeria Department of Public Health Imo State University Owerri Nigeria Department of Pathology Imo State University Teaching Hospital Orlu Nigeria

The role of microbes in the corrosion of metals is due to the chemical activities (metabolism) associated with the microbial growth and reproduction. A lot of researches have shown that enormous loss of resources and even lives has been experienced in many countries of the world due to corrosion. There is therefore need to device a means of combating this menace so as to save different countries of the world including Nigeria the cost encured due to corrosion. This research has helped to determine the role of bacteria in the corrosion of high carbon steel under aerobic and anaerobic conditions was investigated using sulphate reducing bacteria and other aerobes. A sample of high carbon steel grade of chemical composition: 96% iron (Fe), 1.08% carbon (c), 0.349% silicon (Si), 0.841% manganese (Mn), 0.005% phosphorus (P) and 0.005% sulphur (S), was obtained in the form of steel plate. Eighteen (18) samples of the high carbon steel were prepared. Standard microbiological methods were used to isolate aerobic and anaerobic bacteria isolates. The microbes isolated from the soil included;aerobes (Bacillus species, Pseudomonas species) and anaerobes (Desulfovibrio species, Thiobacillus species). The role of bacteria in the corrosion of high carbon steel was estimated using the weight loss technique and the electrochemical potential measurement technique. Eighteen samples of a high carbon steel of known compositions were exposed to sulphate reducing bacteria under different environments (aerobic, anaerobic and control). The physical and chemical changes were examined and monitored on weekly basis for six weeks. It was observed that the coupons immersed in the media with sulphate reducing bacterium underwent fast activation and numerous corrosion sites were formed on the surfaces. The average corrosion rate for six weeks (42 days) period of time as determined by the weight loss method and electrochemical testing were found to be 0.0004595 mm/year, -0.712 mV in aerobic environm

关键词： Bacillus Species Pseudomonas Species Desulfovibrio Species Thiobacillus Species corrosion Steel

comparison of microstructure and mechanical behavior of Ti-35Nb manufactured by laser powder bed fusion from elemental powder mixture and prealloyed powder

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Journal of Materials Science & Technology 2022年第10期105卷 1-16页

作者： J.c.Wang Y.J.Liu S.X.Liang Y.S.Zhang L.Q.Wang T.B.Sercombe L.c.Zhang School of Engineering Edith Cowan University270 Joondalup DriveJoondalupPerthWA 6027Australia School of Engineering M050The University of Western Australia35 Stirling HighwayCrawleyPerthWA 6009Australia Northwest Institute for Nonferrous Metal Research Xi’an 710016China State key Laboratory of Metal Matrix composites School of Material Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China

Although different types of powder feedstock are used for additive manufacturing via laser powder bed fusion(L-PBF),limited work has attempted to directly compare the microstructure and mechanical behavior of components manufactured from those powder *** work investigated the microstructure,phase composition,melt pool morphology,and mechanical properties of a prealloyed Ti-35Nb alloy manufactured using L-PBF and compared these to their counterparts produced from elemental powder *** samples manufactured from the powder mixture are composed of randomly distributed undissolved Nb in theα/βmatrix,resulting from the unstable melt pool during the melting of the powder *** contrast,parts produced from prealloyed powder display a homogeneous microstructure withβandαphases,owing to the full melting of prealloyed powder,therefore,a more stable melt pool to achieve a homogeneous *** Ti-35Nb manufactured from prealloyed powder exhibits large tensile ductility(about 10 times that of the counterparts using mixed powder),attributed to the high homogeneity in microstructure and chemical composition,strong interface bonding,relatively low oxygen content,and the existence of a large amount ofβ*** work sheds insights into understanding the effect of powder feedstock on the melt pool stability therefore the microstructure and mechanical behavior of the resultant parts.

关键词： Titanium-niobium Powder bed fusion Additive manufacturing Melt pool stability Microstructure Mechanical properties

Three new records of cortinarius(cortinariaceae)for the Turkish Mycota from Trabzon,Turkey

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Studies in Fungi 2020年第1期5卷 517-525页

作者： Sesli E ÖrtücüS Trabzon University Fatih Faculty of EducationMathematics and Science EducationDepartment of BiologyTrabzonTurkey Erzurum Technical University High Technology Research and Application CentreErzurumTurkey

Basidiomata of cortinarius were collected during the field studies in 2019 and identified based on both morphological and molecular *** cortinarius species *** cadi-aguirrei,*** and *** are recorded for the first time... 详细信息

关键词： Agaricales Basidiomycota ITS identification taxonomy

cERTAIN ASYMPTOTIc EXPANSIONS FOR LAGUERRE POLYNOMIALS AND cHARLIER POLYNOMIALS

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Analysis in Theory and Applications 1995年第1期11卷 94-104页

作者： L. c. Hsu Dalian University of Technology China

Here proposed are certain asymptotic expansion formulas for Ln(w-1)(λz) and cn(ω)(λz) in whichO(λ) and n = 0(λ1/2 )(λ→∞) , z being x complex number. Also presented are certain estimates for the remainders(erro... 详细信息

关键词： cERTAIN ASYMPTOTIc EXPANSIONS FOR LAGUERRE POLYNOMIALS AND cHARLIER POLYNOMIALS