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Evaluation of Biodegradation in Aqueous Medium of Poly(Hydroxybutyrate-co-Hydroxyvalerate)/carbon Nanotubes Films in Respirometric System

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Journal of Renewable Materials 2019年第2期7卷 117-128页

作者： Larissa Stieven Montagna Isabela cÉSAR Oyama Rita de cÁSSIA Barbosa camargo Lamparelli ana Paula Silva THAIS Larissa do Amaral Montanheiro ana Paula Lemes Federal University of São Paulo(UNIFESP) Institute of Science and TechnologyTechnology Laboratory of Polymers and Biopolymers(TecPBio)Talim330São Josédos CamposSP12231-280BrazilSão Josédos CamposSPBrazil

Biodegradable polymers have been increasingly used for scientific and commercial applications because they are similar to some conventional thermoplastics and exhibit the ability of ***(3-hydroxybutyrate-co-3-hydroxyvalerate)(PHBV)nanocomposites films with 1 and 2 wt% of carbon nanotubes(cNT)were prepared by solution mixing,followed by solvent *** this work,PHBV/cNT nanocomposites were submitted to biodegradation in an aqueous medium for 34 days through a respirometric ***,the PHBV films were analyzed by the cO2 production and mineralization as a response of a microbial attack,which was monitored by back titration during all the *** films were also characterized by measuring the weight loss;crystallinity was evaluated by differential scanning calorimetry(DSc)and the surface morphology by scanning electron microscopy(SEM).By analyzing the weight loss of the films,it was observed that adding cNT increases the resistance to biodegradation *** obtained values of cO2 production and mineralization of the samples,as well as the values of weight loss,showed that the biodegradation of PHBV/cNT nanocomposites was minor in comparison to neat *** addition of cNT in PHBV matrix influences the surface morphology,causing the presence of cavities and an increase of roughness.

关键词： Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) carbon nanotube nanocomposites biodegradation in aqueous medium

A procedure to assess the spatial variability in the importance of abiotic factors affecting distributions： the case of world freshwater fishes

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current Zoology 2018年第5期64卷 549-557页

作者： ana M. MANJARRES-HERNANDEZ castor GUISANDE Emilio GARciA-ROSELLO Patricia PELAYO-VILLAMIL Jacinto gonzalez-DAcOSTA Juirgen HEINE Luis gonzalez VILAS carlos GRanaDO-LORENclO Santiago R. DUQUE Jorge M. LOBO alnstituto Amazonico de Investigaciones-IMANI Universidad Nacional de Colombia Leticia A.A. 215 Colombia 910001 Facultad de ciencias del Mar Universidad de Vigo Vigo 36310 Spain Departamento de Informatica Edificio Fundicien Universidad de Vigo Vigo 36310 Spain Grupo de Iciologia Universidad de Antioquia Medellin Colombia 050010 eDepartamento de Biologia Vegetal y Ecologia Facultad de Biologia Universidad de Sevilla Sevilla 41080 Spain Departamento de Biogeografia y cambio Global Museo Nacional de Ciencias Naturales (CSIC) Calle de Jose Gutierrez Abascal 2 Madrid 28006 Spain

Understanding the factors shaping species＇ distributions is a key longstanding topic in ecology with unresolved issues. The aims were to test whether the relative contribution of abiotic factors that set the geographical range of freshwater fish species may vary spatially and/or may depend on the geographical extent that is being considered. The relative contribution of factors, to discriminate between the conditions prevailing in the area where the species is present and those existing in the considered extent, was estimated with the instability index included in the R pack- age SPEDInstabR. We used 3 different extent sizes： 1） each river basin where the species is present （local）; 2） all river basins where the species is present （regional）; and 3） the whole Earth （global）. We used a data set of 16,543 freshwater fish species with a total of 845,764 geographical records, together with bioclimatic and topographic variables. Factors associated with tempera- ture and altitude show the highest relative contribution to explain the distribution of freshwater fishes at the smaller considered extent. Altitude and a mix of factors associated with temperature and precipitation were more important when using the regional extent. Factors associated with precipitation show the highest contribution when using the global extent. There was also spatial variability in the importance of factors, both between species and within species and from region to region. Factors associated with precipitation show a clear latitudinal trend of decreasing in importance toward the equator.

关键词： anisotropic predictors environmental data selection geographical background non-stationary predictors

A two-stage process with temperature-shift for enhanced anthocyanin production in strawberry cell suspension cultures

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Science china chemistry 1999年第4期42卷 345-350页

作者：张卫 Shintaro Furusaki chris franco Department of chemistry and Biotechnology Graduate School of Engineering The University of Tokyo 7-3-1 Hongo Bunkyo-ku Tokyo 113 Japan Biotechnology School of Medicine Flinders University of South Australia Bedford Park SA 5042 Australia

A two-stage process with temperature-shift has been developed to enhance the anthocyanin yield in suspension cultures of strawbeny cells. The effect of the temperature-shift interval and the shift-time point was investigated for the optimization of this strategy. In this process, strawbeny cells were grown at 30°c (the optimum temperature for cell gowth) for a certain period as the first stage, with the temperature shifted to a lower temperature for the second stage. In response to the temperature shift-down, anthocyanin synthesis was stimulated and a higher content could be achieved than that at both boundary temperatures but cell growth was suppressed. When the lower boundary temperature. was decreased, cell growth was lowered and a delayed, sustained maximum anthocyanin content was achieved. Anthocyanin synthesis was strongly influenced by the shift-time point but cell growth was not. consequently, the maximum anthocyanin content of 2.7 mg.g-fresh cell-1 was obtained on day 9 by a temperature-shift from 309°c, after 3-d culture, to 15°c. The highest anthocyanin yield of 318 mg. L-1 on day 12 was achieved when the temperature was shifted from 30°c, after 5-d culture, to 20°c. For a global optimization of both the yield and productivity, the optimum anthocyanin yield and productivity of 272 mg.L-1 1 and 30.2 mg.L-1d1 on day 9 were achieved by a two-stage culture with a temperature-shift from 30°c after 3 d to 20°c.

关键词： strawberry cell suspension cultures anthocyanin temperature two-stage culture temperature-shift.

Investigation of chlorinated phenols sorption mechanisms on different layers of the Danube alluvial sediment

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Journal of Environmental Sciences 2020年第12期32卷 134-142页

作者： Tamara Apostolovic Jelena Trickovic Marijana Kragulj Isakovski Branislav Jovic Snežana Maletic Aleksandra Tubic Jasmina Agbaba University of Novi Sad Faculty of SciencesDepartment of ChemistryBiochemistry and Environmental ProtectionTrg Dositeja Obradovica 3Novi SadSerbia

The characteristics of the Danube river alluvial sediment are of great importance in assessing the risk for transport of pollutants to drinking water sources. characterization of the sediment column layers has shown that the alluvial sediment, sampled near the city of Novi Sad, is a mesoporous sandy material with certain differences in the properties of individual layers. In order to investigate the sorption mechanisms of four chlorinated phenols(cPs) on the alluvial deposit, static sorption experiments were performed at pH 4, 7 and 10. The results of sorption experiments, confirmed by principal components analysis sugest different mechanisms govern the sorption process at different p H conditions. This can be attributed to the molecular characteristics of cPs, geosorbent properties and to variations in the surface charge of the sorbent at different p H conditions.

关键词： Sorption mechanisms chlorinated phenols Alluvial sediment Principal component analysis

Ni/Al Intermetallics Plasma Transferred Arc Processing

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材料热处理学报 2004年第5B期25卷 948-951页

作者： Veronica A. B. Almeida ana Sofia c. M. D'Oliveira Master student - PIPE Federal University of Parana Curitiba/BrazilMechanical Engineering Department Federal University of Parana Curitiba/Brazil

In-situ alloy development during surface processing allows for a limitless materials selection to protect components exposed to severe service conditions. In fact surface alloying offers the possibility to strengthen surface components with alloys that would not be possible to process otherwise. This work used Plasma transferred arc (PTA) hardfacing for surface alloying. Different amounts of aluminium powder, 5-25%, were added to a Ni based superalloy, from Hastealloy c family, in the atomized form. The mixture was homogeneized in a ball mill and PTA deposited on carbon steel substrate. The influence of different processing parameters on the final surface alloy was evaluated as current intensity and depositing velocity were varied. coatings were characterized by optical and scanning electronic microscopy, X-ray diffraction and Vickers microhardness profiles, under a 500g load. Results showed that PTA hardfacing is an adequate surface alloying. For the conditions tested increasing hardness was obtained by solid solution for the lower amounts of Al added and due to the new intermetallic phases for the richer Al mixture.

关键词： PTA合金等离子转移电弧 Ni/Al金属互化物表面处理

Islet amyloid polypeptide & amyloid beta peptide roles in Alzheimer’s disease:two triggers, one disease

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Neural Regeneration Research 2021年第6期16卷 1127-1130页

作者： Sofia Ferreira ana F.Raimundo Regina Menezes Ivo c.Martins iBET-Instituto de Biologia Experimental e Tecnológica OeirasPortugal cEDOc-chronic Diseases Research center Faculdade de Ciências MédicasUniversidade Nova de LisboaLisboaPortugal ITQB-NOVA Instituto de Tecnologia Química e Biológica António XavierUniversidade Nova de LisboaOeirasPortugal Instituto de Medicina Molecular Faculdade de MedicinaUniversidade de LisboaLisbonPortugal

Alzheimer’s disease(AD)is a neurodegenerative disorder that affects millions *** to population ageing,the incidence of AD is *** patients develop cognitive decline and dementia,features for which is known,requiring permanent *** poses a major socio-economic burden on healthcare systems as AD patients’relatives and healthcare workers are forced to cope with rising numbers of affected *** recent advances,AD pathological mechanisms are not fully ***,it is clear that the amyloid beta(Aβ)peptide,which forms amyloid plaques in AD patients’brains,plays a key *** 2 diabetes,the most common form of diabetes,affects hundreds of million people *** amyloid polypeptide(IAPP)is a hormone coproduced and secreted with insulin in pancreatic β-cells,with a key role in diabetes,as it helps regulate glucose levels and control adiposity and *** to Aβ,IAPP is very amyloidogenic,generating intracellular amyloid deposits that causeβ-cell dysfunction and *** is now clear that IAPP can also have a pathological role in AD,decreasing cognitive *** harms the blood-brain barrier,directly interacts and co-deposits with Aβ,promoting diabetes-associated *** can cause a metabolic dysfunction in the brain,leading to other diabetes-related forms of ***,here we discuss IAPP association with diabetes,Aβand dementia,in the context of what we designate a“diabetes brain phenotype”AD *** approach helps to set a conceptual framework for future IAPP-based drugs against AD.

关键词： aggregation Alzheimer amylin amyloid diabetes islet amyloid polypeptide

Simulation of a Shock Tube with a Small Exit Nozzle

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Journal of Thermal Science 2018年第1期27卷 34-38页

作者： Yigang Luan Matthias Olzmann franco Magagnato Harbin Engineering University HarbinChina Karlsruhe Institute of Technology(KIT) Institute of Physical ChemistryKaiserstrasse 1276131 KarlsruheGermany Karlsruhe Institute of Technology(KIT) Institute of Fluid MechanicsKaiserstrasse 1276131 KarlsruheGermany

Shock tubes are frequently used to rapidly heat up reaction mixtures to study chemical reaction mechanisms and kinetics in the field of combustion chemistry [1]. In the present work, the flow field inside a shock tube with a small nozzle in the end plate has been investigated to support the analysis of reacting chemical mixtures with an attached mass spectrometer and to clarify whether the usual assumptions for the flow field and the related ther- modynamics are fulfilled. In the present work, the details of the flow physics inside the tube and the flow out of the nozzle in the end plate have been investigated. Due to the large differences in the typical length scales and the large pressure ratios of this special device, a very strong numerical stiffness prevails during the simulation process. Second-order ROE numerical schemes have been employed to simulate the flow field inside the shock tube. The simulations were performed with the commercial code ANSYS Fluent [2]. Axial-symmetric boundary conditions are employed to reduce the consumption of cPU time. A density-based transient scheme has been used and vali- dated in terms of accuracy and efficiency. The simulation results for pressure and density are compared with ana- lytical solutions. Numerical results show that a density-based numerical scheme performs better when dealing with shock-tube problems [5]. The flow field near the nozzle is studied in detail, and the effects of the nozzle to pressure and temperature variations inside the tube are invcstigatcd. The results show that this special shock-tube setup can be used to study high-temperature gas-phase chemical reactions with reasonable accuracy.

关键词： cFD shock tube low pressure numerical scheme

Effect of Nitrogen Deficiency and Toxicity in Two Varieties of Tomatoes(Lycopersicum esculentum L.)

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Agricultural Sciences 2014年第14期5卷 1361-1368页

作者： Noemi Frias-Moreno Abelardo Nunez-Barrios Ramona Perez-Leal ana cecilia gonzalez-franco Adriana Hernandez-Rodriguez Loreto Robles-Hernandez Plant Physiology Laboratory Facultad de Ciencias AgrotecnologicasUniversidad Autonoma de ChihuahuaChihuahuaMéxico

Tomato is one of the most important vegetables cultivated in Mexico. Nitrogen-based fertilizers have greatly contributed to the increase in tomato production;however, the excessive application of this fertilizer may affect yield and fruit quality. A greenhouse experiment was conducted to evaluate the effect of increasing in rates of nitrogen from deficiency to toxic levels. Five N-treatments (0, 15, 30, 45 and 60 mM of N) were applied in two tomato varieties, caballero and Victoria The optimum N doses for leaf growth in both varieties was 30 mM reaching 13.0 and 13.5 cm in caballero and Victoria respectively. At low toxic levels leaf growth was recovered more easily in caballero than Victoria. Nitrate concentration for the low toxicity treatment was greater in leaf and stems for caballero than Victoria;conversely nitrate in fruits was higher in Victoria. Final yield per plant was not statistically different between varieties except at the low toxic treatment where caballero had a yield of 780 g per plant compared to that of 330 g per plant of Victoria. Tomato quality was also affected by the applied N-doses, where treatment 30 mM reached the maximum fruit firmness in both varieties while high toxic N-levels decreased significantly this parameter. Soluble solids and titratable acidity increased with increased N-Doses. caballero variety seems to be more tolerant than Victoria at low levels of N-toxicity.

关键词： Tomato Nitrogen Deficiency Toxicity

Patterning the neuronal cells via inkjet printing of self-assembled peptides on silk scaffolds

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Progress in Natural Science:Materials International 2020年第5期30卷 686-696页

作者： Weizhen Sun Yi Zhang David A.Gregory ana Jimenez-franco Mhd anas Tomeh Songwei Lv Jiqian Wang John W.Haycock Jian R.Lu Xiubo Zhao Department of chemical and Biological Engineering University of Sheffield Department of Materials Science & Engineering University of Sheffield School of Pharmacy Changzhou University centre for Bioengineering and Biotechnology China University of Petroleum East China School of Physics and Astronomy University of Manchester

The patterning of neuronal cells and guiding neurite growth are important for neuron tissue engineering and cell-based biosensors. In this paper, inkjet printing has been employed to pattern self-assembled I3QGK peptide nanofibers on silk substrates for guiding the growth of neuron-like Pc12 cells. Atomic force microscopy(AFM)confirmed the dynamic self-assembly of I3QGK into nanofiber structures. The printed self-assembled peptide strongly adheres to regenerated silk fibroin(RSF) substrates through charge-charge interactions. It was observed that in the absence of I3QGK, Pc12 cells exhibited poor attachment to RSF films, while for RSF surfaces coated or printed with peptide nanofibers, cellular attachment was significantly improved in terms of both cell density and morphology. AFM results revealed that peptide nanofibers can promote the generation of axons and terminal buttons of Pc12 cells, indicating that I3QGK nanofibers not only promote cellular attachment but also facilitate differentiation into neuronal phenotypes. Inkjet printing allows complex patterning of peptide nanofibers onto RSF substrates, which enabled us to engineer cell alignment and provide an opportunity to direct axonal development in vitro. The live/dead assay showed that printed I3QGK patterns exhibit no cytotoxicity to Pc12 cells demonstrating potential for future nerve tissue engineering applications.

关键词： Neurobiology Micro-patterning Inkjet printing Self-assembling peptides Pc12 cells