检索结果-南通市图书馆

Impact of Natural Oil-Based Recycled Polyols on Properties of cast Polyurethanes

在线全文

学校读者我要写书评

暂无评论

Journal of Renewable Materials 2018年第7期6卷 697-706页

作者： Hynek Beneš Aleksandra Paruzel JiříHodan olga Trhlíková Institute of Macromolecular Chemistry AS CR v.v.i.Heyrovsky Sq.216206 Prague 6Czech Republic

In this study, castor oil, rapeseed oil and medium chain triglycerides of coconut oil, were transesterified bymeans of 2-ethyl-2-hydroxymethyl-1,3-propanediol (trimethylolpropane) and consequently used to convertpolycarbonate waste from end-of-life vehicles into liquid polyols. The prepared recycled polyols, composeduniquely of renewable and recycled components, had a hydroxyl number of ca. 250 mg KOH·g−1. They weresuccessfully applied as 100% replacement of a virgin polyol for preparation of solid crosslinked polyurethanes(PU) by solvent-free casting. The produced rigid cast PU exhibited the main transition temperature rangingfrom 44°C to 53°C, the hardness value from 46 to 61 Shore D and the beneficial low water absorption (0.4-0.5wt.%). The PU network structure was highly influenced by the presence of aromatic structures ofpolycarbonate-units and fatty acid compositions. A suitable selection of natural oil thus enabled to adjustthermo-mechanical properties and promote excellent optical transparency of the produced PU.

关键词： Natural oil cast polyurethane bio-based polycarbonate waste recycling

Fractionation and fixation of rare earth elements in soils:Effect of spiking with lanthanum,cerium,and neodymium chlorides

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Rare Earths 2022年第1期40卷 143-152页

作者： olga B.Rogova Petr S.Fedotov Rustam Kh.Dzhenloda Vasily K.Karandashev V.V.Dokuchaev Soil Science Institute Russian Academy of Sciences7 Building 2 Pyzhevskiy Side StreetMoscow119017Russia V.I.Vernadsky Institute of Geochemistry and Analytical Chemistry Russian Academy of Sciences19 Kosygin StreetMoscow119991 Russia National University of Science and Technology'MISiS' 4 Leninsky ProspectMoscow119049Russia The Institute of Microelectronics Technology and High-Purity Materials Russian Academy of Sciences6 Institution StreetChernogolovka142432Russia

Industrial and agricultural activities lead to the release of rare earth elements(REEs)in wastewater and aquatic ecosystems,and their accumulation in soils.However,the behavior of REEs in soils remains somewhat unclear.In the present work the fractionation and fixation of REEs in soddy-podzolic and chernozem soils spiked with La,Ce,and Nd chlorides were studied using dynamic(continuous flow)extraction,which allows natural conditions to be mimicked and artefacts to be minimised.The eluents applied are aimed to dissolve exchangeable,specifically sorbed,bound to Mn oxides,bound to metal-organic complexes,and bound to amorphous and poorly ordered Fe/Al oxides fractions extractable by 0.05 mol/L ca(NO_(3))2,0.43 mol/L CH_(3)COOH,0.1 mol/L NH_(2)OH·HCl,0.1 mol/L K_(4)P_(2)O_(7) at pH 11,and 0.1 mol/L(NH4)_(2)C_(2)O_(4) at pH 3.2,respectively.It is found that the fixations of added La,Ce,and Nd in the form of metal-organic complexes is predominant for both types of soils:35%-38%in soddy-podzolic soil and 50%-79%in chernozem.The fixation of added elements in the first three fractions(exchangeable,specifically sorbed,and bound to Mn oxides)is significant for soddy-podzolic soil(5%-25%).For chernozem,the relative contents of added Ce and Nd in these fractions are nearly negligible.Only the content of exchangeable La is notable,about 5%.Adding any of three elements(La,Ce,or Nd)at the level of100 mg/kg to an initial sample results in changing the fractionation and bioaccessibility of other REEs present in soil.Their contents increase in the first three fractions and decrease in fifth(oxalate extractable)fraction for both soddy-podzolic soil and chernozem.The main difference is the behavior of REEs in pyrophosphate extractable fraction.For soddy-podzolic soil,adding La,Ce,or Nd results in decreasing the contents of other REEs associated with organic matter.For chernozem,on the contrary,the contents of REEs in the form of metal-organic complexes slightly increase.These processes may be attributed to competitive binding of elem

关键词： Rare earth elements Soddy-podzolic soil Chernozem Fractionation Competitive binding

RasGRP Ras guanine nucleotide exchange factors in cancer

在线全文

学校读者我要写书评

暂无评论

Frontiers in Biology 2013年第5期8卷 508-532页

作者： olga KSIONDA Andre LIMNANDER Jeroen P. ROOSE Department of Anatomy University of California San Francisco San Francisco CA 94143 USA

RasGRP proteins are activators of Ras and other related small GTPases by the virtue of functioning as guanine nucleotide exchange factors （GEFs）. In vertebrates, four RasGRP family members have been described. RasGRP-1 through -4 share many structural domains but there are also subtle differences between each of the different family members. Whereas SOS RasGEFs are ubiquitously expressed, RasGRP proteins are expressed in distinct patterns, such as in different cells of the hematopoietic system and in the brain. Most studies have concentrated on the role of RasGRP proteins in the development and function of immune cell types because of the predominant RasGRP expression profiles in these cells and the immune phenotypes of mice deficient for Rasgrp genes. However, more recent studies demonstrate that RasGRPs also play an important role in tumorigenesis. Examples are skin- and hematological- cancers but also solid malignancies such as melanoma or prostate cancer. These novel studies bring up many new and unanswered questions related to the molecular mechanism of RasGRP-driven oncogenesis, such as new receptor systems that RasGRP appears to respond to as well as regulatory mechanisms for RasGRP expression that appear to be perturbed in these cancers. Here we will review some of the known aspects of RasGRP biology in lymphocytes and will discuss the exciting new notion that RasGRP Ras exchange factors play a role in oncogenesis downstream of various growth factor receptors.

关键词： Ras signaling lymphocytes cancer RasGRP receptor

Mechanisms of retinal neuroprotection of calcium dobesilate：therapeutic implications

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Neural Regeneration Research 2017年第10期12卷 1620-1622页

作者： olga Simó-Servat Cristina Solà-Adell Patricia Bogdanov Cristina Hernández Rafael Simó Diabetes and Metabolism Research Unit Vall d'Hebron Research InstituteCIBERDEM(Instituto de Salud CarlosⅢ)BarcelonaSpain

Current treatments for diabetic retinopathy （DR） are based on laser photocoagulation and intravitreal injections of corti- costeroids or anti-vascular endothelial growth factor （VEGF） agents. These treatments are applicable only at advanced stages of the disease. In addition, they are expensive, require a vitreo- retinal specialist and are associated with significant adverse ef- fects. Therefore, new pharmacological treatments for the early stages of the disease are needed.

关键词： ca Mechanisms of retinal neuroprotection of calcium dobesilate:therapeutic implications

Perioperative coagulation activation after permanent pacemaker placement

在线全文

学校读者我要写书评

暂无评论

World Journal of cardiology 2023年第4期15卷 174-183页

作者： Roman Kalinin Igor Suchkov Vladislav Povarov Nina Mzhavanadze olga Zhurina Department of cardiovascular Endovascular Surgery and Diagnostic RadiologyRyazan State Medical UniversityRyazan 390026Russia Department of Surgical Treatment of cardiac Arrhythmias and cardiac Pacing Ryazan State"Regional Clinical Cardiology Dispensary"Ryazan 390026Russia Scientific and Clinical Center for Hematology Oncology and ImmunologyRyazan State Medical UniversityRyazan 390026Russia

BACKGROUND Bradyarrhythmias are typically treated with permanent pacemakers(PM). The elimination of bradyarrhythmia by PM implantation improves the patient’s quality of life and prognosis, but it can also result in a number of sequalae. It is still unclear how PM implantation affects the hemostasis system’s parameters and how such parameters relate to different consequences after PM placement.AIM To assess the blood coagulation factor activity in PM patients throughout the perioperative period.METHODS Patients treated in the Department of Surgical Therapy of cardiac Arrhythmias and Pacing at the Ryazan State "Regional Clinical cardiology Dispensary" from April 2020 to December 2021 were included in the study. Before surgery, 7 and 30 d after PM placement, peripheral venous blood samples were withdrawn to measure the level of blood coagulation factor Ⅰ(FⅠ) and the activity of blood coagulation factors Ⅱ(FⅡ), Ⅴ(FⅤ), Ⅶ(FⅦ), Ⅷ(FⅧ), ⅸ(Fⅸ), ⅹ(Fⅹ), Ⅺ(FⅪ), Ⅻ(FⅫ). We used an automatic coagulometer Sysmex ca 660(Sysmex Europe, Germany) and reagents from Siemens(Siemens Healthcare Diagnostics Products GmbH, Germany).RESULTS The study included 146 patients. The activity of factors FⅤ [147.7(102.1-247.55)% vs 103.85(60-161.6)% vs 81.8(67.15-130.65)%, P = 0.002], FⅧ [80.4(60.15-106.25)% vs 70.3(48.5-89.1)% vs 63.7(41.6-88.25)%, P = 0.039], Fⅸ [86.2(70.75-102.95)% vs 75.4(59.2-88.3)% vs 73.9(56.45-93.05)%, P = 0.014], Fⅹ [188.9(99.3-308.18)% vs 158.9(83.3-230)% vs 127.2(95.25-209.35)%, P = 0.022], FⅪ [82.6(63.9-103.6)% vs 69.75(53.8-97.6)% vs 67.3(54.25-98.05)%, P = 0.002], FⅫ [87.6(67.15-102.3)% vs 78.9(63.4-97.05)% vs 81.2(62.15-97.4)%, P cally significant changes in the FVII activity within 30 d after PM placement [182.2(85.1-344.8)% vs 157.2(99.1-259)% vs 108.9(74.9-219.8)%, P = 0.128]. Subgroup analysis revealed

关键词： Hemostasis Blood coagulation cardiac pacemaker Anticoagulants Postoperative complications

Controlled Wettability of Polymers via Environmental Crazing

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2022年第10期40卷 1307-1314,I0012页

作者： Alena Yu.Yarysheva Larisa M.Yarysheva Fedor V.Drozdov olga V.Arzhakova Aziz M.Muzafarov Faculty of Chemistry Lomonosov Moscow State UniversityLeninskieGory 1-3Moscow 119991Russia Institute of Synthetic Polymer Materials RAS ul.Profsoyuznaya 70Moscow 117393Rusia

This work highlights the benefits of environmental crazing for the control over the hydrophilic-lipophilic balance of glassy amorphous and semicrystalline polymers:poly(ethylene terephthalate)(PET)and biodegradable polycaprolactone(PCL).Task-oriented encapsulation of diverse commercial and natural hydrophilic(polyethyleneoxide,polyvinylpyrrolidone,gelatin)and hydrophobic guest additives(perfluoroorgano siloxanes,water-repellent impregnation)into mesoporous host polymer(PET,PCL)matrixes allows targeted control over the wettability of the resultant nanocomposite materials.Depending on the nature of the guest additive,the properties of the modified polymers can be varied from hydrophilic to hydrophobic:contact angle(ca)of PET can be adjusted from 47_(⊥)/38_(||)to 130_(⊥)/117_(||)°(for initial PET,ca=82°)and ca of PCL from 40°to 114°(for initial PCL ca=75°).The unique benefits of environmental crazing for structural modification are related to the universal character of this approach which can be applied to a broad range of polymers and allows preparation of diverse high-performance materials with tunable hydrophilic-lipophilic balance.

关键词： Wettability Hydrophilic-hydrophobic balance Contact angle Environmental crazing Poly(ethylene terephthalate) Polycaprolactone

Inhalation treatment of lung cancer: the influence of composition, size and shape of nanocarriers on their lung accumulation and retention

在线全文

学校读者我要写书评

暂无评论

cancer Biology & Medicine 2014年第1期11卷 44-55页

作者： olga B.Garbuzenko Gediminas Mainelis Oleh Taratula Tamara Minko Department of Pharmaceutics Ernest Mario School of Pharmacy Rutgers The State University of New Jersey Department of Environmental Sciences Rutgers The State University of New Jersey Environmental and Occupational Health Sciences Institute Department of Pharmaceutical Sciences Oregon State University Rutgers cancer Institute of New Jersey

Objective: Various nanoparticles have been designed and tested in order to select optimal carriers for the inhalation delivery of anticancer drugs to the lungs. Methods: The following nanocarriers were studied: micelles, liposomes, mesoporous silica nanoparticles(MSNs), poly propyleneimine(PPI) dendrimer-siRNA complexes nanoparticles, quantum dots(QDs), and poly(ethylene glycol) polymers. All particles were characterized using the following methods: dynamic light scattering, zeta potential, atomic force microscopy, in vitro cyto- and genotoxicity. In vivo organ distribution of all nanoparticles, retention in the lungs, and anticancer effects of liposomes loaded with doxorubicin were examined in nude mice after the pulmonary or intravenous delivery. Results: Significant differences in lung uptake were found after the inhalation delivery of lipid-based and non-lipid-based nanoparticles. The accumulation of liposomes and micelles in lungs remained relatively high even 24 h after inhalation when compared with MSNs, QDs, and PPI dendrimers. There were notable differences between nanoparticle accumulation in the lungs and other organs 1 and 3 h after inhalation or intravenous administrations, but 24 h after intravenous injection all nanoparticles were mainly accumulated in the liver, kidneys, and spleen. Inhalation delivery of doxorubicin by liposomes significantly enhanced its anticancer effect and prevented severe adverse side effects of the treatment in mice bearing the orthotopic model of lung cancer.Conclusion: The results of the study demonstrate that lipid-based nanocarriers had considerably higher accumulation and longer retention time in the lungs when compared with non-lipid-based carriers after the inhalation delivery. These particles are most suitable for effective inhalation treatment of lung cancer.

关键词：纳米载体肺部肺癌治疗积聚硅纳米颗粒组成形状

Influence of tannin-rich pine bark supplementation in the grain mixes for meat goats:Growth performance,blood metabolites,and carcass characteristics

在线全文

学校读者我要写书评

暂无评论

Animal Nutrition 2020年第1期6卷 85-91页

作者： Desnatie Reynolds Byeng Ryel Min Nar Gurung Wendell McElhenney Jung Hoon Lee Sandra Solaiman olga Bolden-Tiller Tuskegee University TuskegeeAL36088USA United States Department of Agriculture/Agricultural Research Service(USDA/ARS) BushlandTX79012USA Department of Agricultural Sciences Fort-Valley State UniversityFort-ValleyGA31030USA

The objective was to evaluate the use of condensed tannin(CT)-rich ground pine bark(PB)in grain mixed diets on meat goat growth performance,blood metabolites,and carcass characteristics.Twenty four Kiko crossbred(capra aegugrus hircus)growing male kids(BW=36.9±2,5 kg)at approximately 8 months of age were assigned randomly to 2 treatments with 3 replicates per treatment and 4 goats per replicate.The goats were fed grain mixed diets composed of either 30%bermudagrass hay(BGH)plus concentrate(control)or 30%PB plus concentrate.Diets were fed at 1.2%of BW.In addition,all goats grazed a crabgrass/bermudagrass(CB)-based pasture.The feeding trial lasted for 55 d.Using ground PB as a supplement did not negatively affect BW,average daily gain(ADG),carcass characteristics,meat pH,and meat color compared to the control diet.Plasma gamma-glutamyl transferase(P=0.03),glucose(Pca concentrations(P=0.04)were higher for PB than for BGH,respectively.The 30%PB supplementation does not negatively affect animal performance,blood metabolites,and carcass parameters.

关键词： Pine bark Goats Animal performance Blood metabolites carcass traits

Identification and Preliminary Characterization of a New Chemical Affecting Glucosyltransferase Activities Involved in Plant Cell Wall Biosynthesis

在线全文

学校读者我要写书评

暂无评论

Molecular Plant 2008年第6期1卷 977-989页

作者： olga Zabotina Erik Maim Georgia Drakakaki Vincent Bulone Natasha Raikhel Institute for Integrative Genome Biology Center for Plant Cell Biology and Department of Botany and Plant Sciences University of California Riverside CA92521 USA School of Biotechnology Royal Institute of Technology (KTH) AlbaNova University Center Stockholm SE-106 91 Sweden Present address: Department of Biochemistry Biophysics and Molecular Biology Iowa State University Ames IA 50014 USA

Chemical genetics as a part of chemical genomics is a powerful and fast developing approach to dissect biological processes that may be difficult to characterize using conventional genetics because of gene redundancy or lethality and, in the case of polysaccharide biosynthesis, plant flexibility. Polysaccharide synthetic enzymes are located in two main compartments--the Golgi apparatus and plasma membrane-and can be studied in vitro using membrane fractions. Here, we first developed a high-throughput assay that allowed the screening of a library of chemicals with a potential effect on glycosyltransferase activities. Out of the 4800 chemicals screened for their effect on Golgi glucosyltransferases, 66 compounds from the primary screen had an effect on carbohydrate biosynthesis. Ten of these compounds were confirmed to inhibit glucose incorporation after a second screen. One compound exhibiting a strong inhibition effect （ID 6240780 named chemical A） was selected and further studied. It reversibly inhibits the transfer of glucose from UDP-glucose by Golgi membranes, but activates the plasma membrane-bound callose synthase. The inhibition effect is dependent on the chemical structure of the compound, which does not affect endomembrane morphology of the plant cells, but causes changes in cell wall composition. Chemical A represents a novel drug with a great potential for the study of the mechanisms of Golgi and plasma membrane-bound glucosyltransferases.

关键词： cell walls callose synthase chemical screening and identification glycosyltransferase Golgi plasma membrane