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Crystallization Kinetics of Poly(3-hydroxybutyrate) Granules in Different Environmental Conditions

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Journal of Biomaterials and Nanobiotechnology 2011年第3期2卷 301-310页

作者： Michael porter Jian Yu 不详

Poly(3-hydroxybutyrate) (PHB) is a natural biopolyester accumulated in microbial cells as tiny amorphous granules. The nano- micro-particles have a variety of potential applications and behave differently in different environments. In this work, the in situ crystallization of native PHB granules was investigated under different environmental conditions. The isothermal crystallization kinetics of the granules was shown to follow Avrami’s equation. The model parameter describing crystal growth is a function of temperature or pH and estimated from in situ crystallization measurements with attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. Empirical equations describing crystal growth are derived for the parameter values. PHB granules heated at 80-140°C in acidic solution (pH 2) up to 4 hr showed an increase in crystallinity from about 5% to 35% and moderate particle aggregation. PHB granules suspended in alkaline solutions (pH 9-12) at room temperature up to 4 hr showed an increase in crystallinity up to 45% and very little particle aggregation. It was found that the amorphousness of PHB granules in vivo is stabilized by water, lipids and proteins. Upon removal of these impurities, partial crystallization is induced which may inhibit extensive particle aggregation.

关键词： Avrami model crystallization kinetics PHA PHB granules biopolyester particles

Introduction to Operations Research 7th ed.

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丛书名： McGraw-Hill series in industrial engineering and management science

2001年

作者： frederick s. Hillier Gerald J. Lieberman

来源：畅想之星图书光盘版（南... 评论

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管理科学概论

管理科学概论

Cu-Bearing Mokama Granite Prospect of the Kibara Belt in the Maniema Province, DRC: A Preliminary Petrography, Geochemistry, and Fluid Inclusion study

丛书名：决策科学丛书

2013年

作者： frederick s. Hillier[等]原

来源：畅想之星图书光盘版（南... 评论

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Open Journal of Geology 2023年第10期13卷 1007-1023页

作者： Douxdoux Kumakele Makutu Ivan Bongwe Chris Musomo Mfumu frederick Makoka Mwanza Jean-Pierre Bulambo Pierre Kambuli Kaseti Energy Resource Department College of Engineering Inha University Incheon Republic of Korea Department of Geosciences Kinshasa University Kinshasa Democratic Republic of the Congo Department of Geology University of Lubumbashi Lubumbashi Democratic Republic of the Congo

The Mokama granites are located in the Kibara belt (KIB) and hosts tin oxide group minerals (TOGM: sn-W), and sulfide group minerals (sGM: Cu-Zn-Fe-As). The essential of Cu mineralization (non-economic deposit) is disseminated inside the rock and consists of minerals (Raman, EPMA and metallographic microscopy) including chalcopyrite and bornite that are replaced by chalcocite and covellite, and the last also replaced later by malachite. The chemistry (XRF, LA-ICP-Ms) of these peraluminous s-type leucogranites show siOsub>2sub> (71 wt% - 79 wt%), AsI (1.4 - 3.1 molar), and are enriched in Rb (681 - 1000 ppm), Ta (12–151 ppm), sn (43 - 142 ppm), Cu (10 - 4300 ppm), Zn (60 - 740 ppm), U (2.2 - 20.7 ppm) while depleted in Zr (20 - 31 ppm), sr (20 - 69 ppm), Hf (1.3 - 2.0 ppm), Th (2.2 - 18.9 ppm), W (9 - 113 ppm), Pb (5 - 50 ppm), Ge (5 - 10 ppm), Cs (21 - 53 ppm) and Bi (0.6 - 17.4 ppm) and low ratios of (La/Yb) N, (Gd/Yb) N, (La/sm) N). Fluid inclusion assemblages (FIAs) hosted in quartz in the Mokama granites show ranges of salinities of 4 - 23 wt% (NaCl equivalent) and homogenization temperatures (Th) of 190°C - 550°C. A boiling assemblage in the granite suggests a fluid phase separation occurred at about 380 - 610 bars, and this corresponds to apparent paleodepths of approximately 1 - 2 km (lithostatic model) or 3 - 5 km (hydrostatic model). FIAs hosted in TOGM such as cassiterite (salinities of 2 wt% - 10 wt% and Th of 220°C - 340°C) helped set up the possible temperature limit of sGM (Cu sulfide) precipitations that are estimated below 200°C.

关键词： Mokama Granites Petrography Geochemistry Cu-Mineralization XRF EPMA LA-ICP-Ms Fluid Inclusion Microthermometry

Changes in fetal mannose and other carbohydrates induced by a maternal insulin infusion in pregnant sheep

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Journal of Animal science and Biotechnology 2015年第2期6卷 222-229页

作者： Laura D Brown stephanie R Thorn Alex Cheung Jinny R Lavezzi frederick C Battaglia Paul J Rozance Perinatal Research Center Division of Neonatology Department of Pediatrics University of Colorado Denver School of Medicine Center for Women’s Health Research University of Colorado Denver School of Medicine

Background： The importance of non-glucose carbohydrates, especially mannose and inositol, for normal development is increasingly recognized. Whether pregnancies complicated by abnormal glucose transfer to the fetus also affect the regulation of non-glucose carbohydrates is unknown. In pregnant sheep, maternal insulin infusions were used to reduce glucose supply to the fetus for both short （2-wk） and long （8-wk） durations to test the hypothesis that a maternal insulin infusion would suppress fetal mannose and inositol concentrations. We also used direct fetal insulin infusions （1-wk hyperinsulinemic-isoglycemic clamp） to determine the relative importance of fetal glucose and insulin for regulating non-glucose carbohydrates. Results： A maternal insulin infusion resulted in lower maternal （50%, P 〈 0.01） and fetal （35-45%, P 〈 0.01） mannose concentrations, which were highly correlated （r^2 = 0.69, P 〈 0.01）. A fetal insulin infusion resulted in a 50% reduction of fetal mannose （P 〈 0.05）. Neither maternal nor fetal plasma inositol changed with exogenous insulin infusions. Additionally, maternal insulin infusion resulted in lower fetal sorbitol and fructose （P 〈 0.01）. Conclusions： Chronically decreased glucose supply to the fetus as well as fetal hyperinsulinemia both reduce fetal non-glucose carbohydrates. Given the role of these carbohydrates in protein glycosylation and lipid production, more research on their metabolism in pregnancies complicated by abnormal glucose metabolism is clearly warranted.

关键词： Fructose Glucose Inositol Insulin Mannose Pregnancy

Risk and Economic Development in the Provision of Public Infrastructure

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Journal of Environmental Protection 2018年第9期9卷 973-990页

作者： frederick Bloetscher Florida Atlantic University Boca Raton USA

A public water and sewer utility is created to develop safe, reliable and financially self-supporting potable water and sanitary sewage systems which will meet the water and sewerage needs of the areas served by the utility;to ensure that existing and future utility facilities are constructed, operated and managed at the least possible cost to the users without outside subsidies;and to develop a system that is compatible with the area’s future growth. To gain efficiencies in operation, these new facilities must be developed in accordance with the latest technical and professional standards to protect the health, safety, and welfare of the citizens served now or in the future. Hence a utility must construct new pipelines, pump stations and other infrastructure, whether that infrastructure is for growth, to improve existing service, or to replace infrastructure that has reached the end of its useful, economic, and/or physical life. In established or stable communities, the replacement of existing infrastructure, where it is no longer economical to operate, is deteriorated to a point where replacement is more cost effective than repairs due to wear, neglect or environmental conditions, or where the infrastructure no longer serves its intended purpose or meets regulatory standards, must be pursued. As a result, many established utilities have capital plans that contain many such replacement projects. The question is how much investment should be made. The intent of this paper is to evaluate investment in infrastructure made by public water and sewer utility systems. What was found among the utilities in Florida that were evaluated was that more than half are underinvesting in their infrastructure. some are not investing at all although more research is needed because it appears that many utilities make large investments periodically as opposed to using pay-as-you-go methods. Large scale investments like bond issues impact rates. Economies-of-scale remain for large utili

关键词： Water sewer Economy-of-scale Utility Finance

Effects of Treatment with Different Combinations of Bisphenol Compounds on the Mortality of Caenorhabditis Elegans

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Biomedical and Environmental sciences 2020年第2期33卷 145-149页

作者： Naomi HAMAMBA LI Jie ZHANG Xiao Wei ZHANG Cai Qin frederick sARPONG ZHOU Xing Hua school of Food and Biological Engineering Jiangsu UniversityZhenjiang 212013Jiangsu China

Bisphenol A(BPA)is believed to affect a variety of physiological functions associated with human diseases[1].Bisphenol F(BPF)is an alternative to bisphenol *** percent of BPF is used as a monomer in the synthesis of polyvinyl chloride(PVC)and other compounds[2].Bisphenol s(BPs)is a structural analog of bisphenol A,which is widely used as a substitute in a variety of daily-use consumer goods and *** compound is often detected in indoor dust,urine,and human blood.

关键词： Effects Treatment Caenorhabditis

New insights into the role of cytochrome P450 reductase (POR) in microsomal redox biology

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Acta Pharmaceutica sinica B 2012年第2期2卷 102-106页

作者： Todd D.porter Department of Pharmaceutical sciences College of PharmacyUniversity of KentuckyLexingtonKY 40536-0596USA

Cytochrome P450 reductase(POR)is an essential electron transfer protein located on the endoplasmic reticulum of most cell types,and has long been appreciated for its role in cytochrome P450-mediated drug *** roles and electron acceptors for POR have been described,but it is largely with the recent availability of POR-null tissues that these supplemental roles for POR have been able to be *** studies have confirmed POR as the principal redox partner for the microsomal P450s responsible for drug and xenobiotic metabolism as well as cholesterol and bile acid synthesis,and for heme oxygenase,which catalyzes the initial step in the breakdown of ***,these studies have revealed that squalene monooxygenase,an enzyme essential to cholesterol synthesis,has a second unknown redox partner in addition to POR,and that 7-dehydrocholesterol reductase,previously proposed to require POR as an electron donor,functions fully independently of *** studies have also helped define the role of cytochrome b5 in P450 catalysis,and raise the question as to the extent to which POR contributes to b5-dependent redox pathways.

关键词： Cytochrome P450 squalene monooxygenase Heme oxygenase Cytochrome b5 Microsomes 7-Dehydrocholesterol reductase

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Hidden Treasures

英语世界 2020年第5期 127-128页

作者： Chris Cavey Jon porter

There’s more to tourism in Britain than you might *** you think of tourist sites in Britain, what do you think of? Big Ben and the Tower of London? Loch Ness? shakespeare’s birthplace at stratford-upon-Avon? There a...

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