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  1 / 102611 MEDLINE  
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PMID:28648851
Autor:Rehal RP; Marbach H; Hubbard ATM; Sacranie AA; Sebastiani F; Fragneto G; Harvey RD
Endereço:Institute of Pharmaceutical Science, King's College London, London, UK.
Título:The influence of mild acidity on lysyl-phosphatidylglycerol biosynthesis and lipid membrane physico-chemical properties in methicillin-resistant Staphylococcus aureus.
Fonte:Chem Phys Lipids; 206:60-70, 2017 Aug.
ISSN:1873-2941
País de publicação:Ireland
Idioma:eng
Resumo:The increased biosynthesis of lysyl-phosphatidylglycerol in Staphylococcus aureus when cultured under conditions of mild acidity and the resultant increased proportion of this lipid in the plasma membrane of the bacterium, alters the physico-chemical properties of lipid bilayers in a manner which is itself dependent upon environmental pH. Clinically relevant strains of S. aureus, both methicillin susceptible and resistant, all exhibited increased lysyl-phosphatidylglycerol biosynthesis in response to mild environmental acidity, albeit to differing degrees, from ∼30% to ∼55% total phospholipid. Polar lipid extracts from these bacteria were analysed by P NMR and reconstituted into vesicles and monolayers, which were characterised by zeta potential measurements and Langmuir isotherms respectively. A combination of increased lysyl-phosphatidylglycerol content and mild environmental acidity were found to synergistically neutralise the charge of the membranes, in one instance altering the zeta potential from -56mV to +21mV, and induce closer packing between the lipids. Challenge of reconstituted S. aureus lipid model membranes by the antimicrobial peptide magainin 2 F5W was examined using monolayer subphase injection and neutron diffraction, and revealed that ionisation of the headgroup α-amine of lysyl-phosphatidylglycerol at pH 5.5, which reduced the magnitude of the peptide-lipid interaction by 80%, was more important for resisting peptide partitioning than increased lipid content alone. The significance of these results is discussed in relation to how colonising mildly acidic environments such as human mucosa may be facilitated by increased lysyl-phosphatidylglycerol biosynthesis and the implications of this for further biophysical analysis of the role of this lipid in bacterial membranes.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Antimicrobial Cationic Peptides); 0 (Phosphatidylglycerols); 42241-11-2 (lysylphosphatidylglycerol); K3Z4F929H6 (Lysine)


  2 / 102611 MEDLINE  
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PMID:28533145
Autor:Sierra MB; Alarcón L; Gerbino D; Pedroni VI; Buffo FE; Morini MA
Endereço:Laboratorio de Fisicoquímica, INQUISUR, Departamento de Química, Universidad Nacional del Sur (UNS)-CONICET, Av. Alem 1253, 8000 Bahía Blanca, Argentina. Electronic address: mbsierra@uns.edu.ar.
Título:Effects of hydroxy-xanthones on dipalmitoylphosphatidylcholine lipid bilayers: A theoretical and experimental study.
Fonte:Chem Phys Lipids; 206:1-8, 2017 Aug.
ISSN:1873-2941
País de publicação:Ireland
Idioma:eng
Resumo:Xanthones and derivatives are natural active compounds whose interest has been increased due to its several pharmacological effects. In this work, effects of hydroxy-xanthones on the physicochemical properties of dipalmitoylphosphatidylcholine (DPPC) liposomes have been investigated in terms of lipid bilayer fluidity, by means of molecular dynamics simulations and temperature dependence of zeta potential studies. Experimental results predict, in good agreement with simulations, that xanthones are able to be incorporated into DPPC liposomes with certain localization, fluidizing the bilayer. Both effects, localization and fluidity were found to be dependent of the number of hydroxilic substituents of the xanthone and the lipid phase state.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Lipid Bilayers); 0 (Xanthones); 2644-64-6 (1,2-Dipalmitoylphosphatidylcholine)


  3 / 102611 MEDLINE  
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PMID:28399653
Autor:Kim YH; Park LK; Yiacoumi S; Tsouris C
Endereço:Georgia Institute of Technology, Atlanta, Georgia 30332-0373.
Título:Modular Chemical Process Intensification: A Review.
Fonte:Annu Rev Chem Biomol Eng; 8:359-380, 2017 Jun 07.
ISSN:1947-5446
País de publicação:United States
Idioma:eng
Resumo:Modular chemical process intensification can dramatically improve energy and process efficiencies of chemical processes through enhanced mass and heat transfer, application of external force fields, enhanced driving forces, and combinations of different unit operations, such as reaction and separation, in single-process equipment. These dramatic improvements lead to several benefits such as compactness or small footprint, energy and cost savings, enhanced safety, less waste production, and higher product quality. Because of these benefits, process intensification can play a major role in industrial and manufacturing sectors, including chemical, pulp and paper, energy, critical materials, and water treatment, among others. This article provides an overview of process intensification, including definitions, principles, tools, and possible applications, with the objective to contribute to the future development and potential applications of modular chemical process intensification in industrial and manufacturing sectors. Drivers and barriers contributing to the advancement of process intensification technologies are discussed.
Tipo de publicação: JOURNAL ARTICLE; REVIEW
Nome de substância:0 (Biofuels)


  4 / 102611 MEDLINE  
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PMID:28686581
Autor:Harmsen S; Wall MA; Huang R; Kircher MF
Endereço:Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, New York, USA.
Título:Cancer imaging using surface-enhanced resonance Raman scattering nanoparticles.
Fonte:Nat Protoc; 12(7):1400-1414, 2017 Jul.
ISSN:1750-2799
País de publicação:England
Idioma:eng
Resumo:The unique spectral signatures and biologically inert compositions of surface-enhanced resonance Raman scattering (SERRS) nanoparticles make them promising contrast agents for in vivo cancer imaging. Our SERRS nanoparticles consist of a 60-nm gold nanoparticle core that is encapsulated in a 15-nm-thick silica shell wherein the resonant Raman reporter is embedded. Subtle aspects of their preparation can shift their limit of detection by orders of magnitude. In this protocol, we present the optimized, step-by-step procedure for generating reproducible SERRS nanoparticles with femtomolar (10 M) limits of detection. We provide ways of characterizing the optical properties of SERRS nanoparticles using UV/VIS and Raman spectroscopy, and their physicochemical properties using transmission electron microscopy and nanoparticle tracking analysis. We introduce several applications of these nanoprobes for biomedical research, with a focus on intraoperative cancer imaging via Raman imaging. A detailed account is provided for successful i.v. administration of SERRS nanoparticles such that delineation of cancerous lesions can be achieved in vivo and ex vivo on resected tissues without the need for specific biomarker targeting. This straightforward, yet comprehensive, protocol-from initial de novo gold nanoparticle synthesis to SERRS nanoparticle contrast-enhanced preclinical Raman imaging in animal models-takes ∼96 h.
Tipo de publicação: JOURNAL ARTICLE


  5 / 102611 MEDLINE  
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PMID:27984227
Autor:Zbytovská J; Gallusová J; Vidlárová L; Procházková K; Simek J; Stepánek F
Endereço:From the *Department of Organic Technology, University of Chemistry and Technology, Prague, Czech Republic; †Department of Clinical Pharmacy, Na Homolce Hospital, Prague, Czech Republic; and ‡Department of Chemical Engineering, University of Chemistry and Technology, Prague, Czech Republic.
Título:Physical Compatibility of Propofol-Sufentanil Mixtures.
Fonte:Anesth Analg; 124(3):776-781, 2017 Mar.
ISSN:1526-7598
País de publicação:United States
Idioma:eng
Resumo:BACKGROUND: Combined infusions of propofol and sufentanil preparations are frequently used in clinical practice to induce anesthesia and analgesia. However, the stability of propofol emulsions can be affected by dilution with another preparation, sometimes leading to particle coalescence and enlargement. Such unwanted effects can lead to fat embolism syndrome after intravenous application. This study describes the physical stability of 5 commercially available propofol preparations mixed with sufentanil citrate solutions. METHODS: Two common markers of emulsion stability were used in this study; namely, the zeta potential and size distribution of the emulsion droplets. Both were measured using dynamic light scattering. The data for the pure propofol preparations and their mixtures with sufentanil citrate solution were compared. RESULTS: The absolute value of zeta potential decreased in 4 of the 5 propofol preparations after they had been mixed with sufentanil citrate. This effect indicates a lowering of repulsive interactions between the emulsion droplets. Although this phenomenon tends to cause agglomeration, none of the studied mixtures displayed a substantial increase in droplet size within 24 hours of blending. However, our long-term stability study revealed the instability of some of the propofol-sufentanil samples. Two of the 5 studied mixtures displayed a continual increase in particle size. The same 2 preparations showed the greatest reductions in the absolute value of zeta potential, thereby confirming the correlation of both measurement methods. The increase in particle size was more distinct in the samples stored at higher temperatures and with higher sufentanil concentrations. CONCLUSIONS: To ensure the microbial stability of an emulsion infusion preparation, clinical regulations require that such preparations should be applied to patients within 12 hours of opening. In this respect, we can confirm that during this period, none of the studied propofol-sufentanil mixtures displayed any physical instability that could lead to particle enlargement; thus, fat embolism should not be a risk after their intravenous application. However, our long-term stability study revealed differences between commercially available preparations containing the same active ingredient; some of the mixtures showed an increase in particle size and polydispersity over a longer period. Although our results should not be generalized beyond the particular propofol-sufentanil preparations and concentrations studied here, they do suggest that, as a general principle, a compatibility study should be performed for any preparation before the first intravenous application to exclude the risk of droplet aggregation.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Anesthetics, Intravenous); 0 (Drug Combinations); AFE2YW0IIZ (Sufentanil); YI7VU623SF (Propofol)


  6 / 102611 MEDLINE  
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PMID:28422036
Autor:Ubetagoyena-Arrieta M; Martínez Sáenz de Jubera J; Corera-Casty MN; González Pérez-Yarza E; García-Albizua I
Endereço:Sección de Nefrología Pediátrica. Hospital Universitario Donostia. San Sebastián. Servicio de Pediatría. Hospital Universitario Donostia. San Sebastián. España.
Título:Physicochemical factors of the urine of children with hypercalciuria.
Título:Características de los factores fisicoquímicos que componen la orina de los niños con hipercalciuria..
Fonte:Arch Esp Urol; 70(3):342-348, 2017 Apr.
ISSN:0004-0614
País de publicação:Spain
Idioma:spa; eng
Resumo:OBJECTIVE: Hypercalciuria is a common lithogenic risk factor. The aim of this study was, first, to study the characteristics of urine biochemical factors of children with hypercalciuria (HC) and compare them with those of children without hypercalciuria. Second, to analyze the differences between children with HC and lithiasis (HCL) and children with HC and no lithiasis (HCNL). METHODS: The sample was composed by 111 cases with HC, divided into 2 groups: HCNL group, consisting of 93 cases with no personal history of kidney stones, and HCL group, 18 cases with personal history of kidney stones. As a cohort control group, 113 healthy children were used. Creatinine, urea, sodium, potassium, chlorine, uric acid, calcium, phosphorus, magnesium and osmolality: blood and 24-hour urine following parameters were determined. Oxalate and citrate were determined in urine. RESULTS: The mean values of natriuresis, uricosuria, phosphaturia, magnesuria, citraturia, calcium oxalate and calcium phosphate saturation were higher in HCNL than in control group. The HCL group had phosphaturia, calcium oxalate and calcium phosphate saturations more elevated compared with the control group. There were no significant differences in urinary excretion of various parameters when the groups HCL and HCNL were compared. CONCLUSIONS: Our results show that children with hypercalciuria without lithiasis associated show an increase in natriuresis, phosphaturia, uricosuria, magnesuria and citraturia. We found no differences between these urinary abnormalities when compared hypercalciuric children without lithiasis with those with hypercalciuria and urolithiasis.
Tipo de publicação: JOURNAL ARTICLE


  7 / 102611 MEDLINE  
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PMID:28199889
Autor:Lesiow T; Rentfrow GK; Xiong YL
Endereço:Department of Quality Analysis, University of Economics, Wroclaw 53-345, Poland.
Título:Polyphosphate and myofibrillar protein extract promote transglutaminase-mediated enhancements of rheological and textural properties of PSE pork meat batters.
Fonte:Meat Sci; 128:40-46, 2017 Jun.
ISSN:1873-4138
País de publicação:England
Idioma:eng
Resumo:The objective of this study was to improve the rheological (storage modulus G'; phase angle δ) and textural (hardness; breaking force) properties of nitrite-cured sausage batters prepared from pale, soft, exudative (PSE) pork with microbial transglutaminase (TG) using isolated myofibrillar protein (MP) or MP extracted by sodium tripolyphosphate (TPP) as substrates. While TG alone significantly enhanced G', δ and hardness, its combination with TPP was more pronounced as these product quality parameters were increased to the level equal to that of the counterpart batter made from normal (red, firm, non-exudative, RFN) pork. The addition of MP had negligible such effect on TG functions. Cooking loss of TG-treated RFN and PSE meat with TPP was minimal but the batters were less bright (L*) than other treatments. Redness (a*) was variable between treatments. Therefore, texture-related properties of comminuted PSE meat products can be restored to the RFN level by TG cross-linking of protein that is extracted by TPP.
Tipo de publicação: COMPARATIVE STUDY; JOURNAL ARTICLE
Nome de substância:0 (Food Additives); 0 (Muscle Proteins); 0 (Pigments, Biological); 0 (Polyphosphates); EC 2.3.2.13 (Transglutaminases); NU43IAG5BC (triphosphoric acid)


  8 / 102611 MEDLINE  
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PMID:28043049
Autor:Del Blanco A; Caro I; Quinto EJ; Mateo J
Endereço:Department of Food Hygiene and Food Technology, University of León, Campus de Vegazana s/n, 24071 León, Spain. Electronic address: ablanr00@estudiantes.unileon.es.
Título:Quality changes in refrigerated stored minced pork wrapped with plastic cling film and the effect of glucose supplementation.
Fonte:Meat Sci; 126:55-62, 2017 Apr.
ISSN:1873-4138
País de publicação:England
Idioma:eng
Resumo:Meat spoilage greatly depends on meat composition and storage conditions. Microbial and biochemical changes in minced pork (100-g portions) wrapped with a polyvinyl chloride film during a 4-day refrigerated storage were studied. As glucose is the first substrate used by spoilage bacteria and when it is depleted bacteria could generate undesirable volatiles, the effect of the addition of glucose to minced meat was also studied. Three treatments were used: control (C), without added glucose, and low and high glucose concentration (L and H), 150mg and 750mg of glucose in 100g of meat, respectively. Spoilage bacteria, pH, redox potential, colour, basic volatile nitrogen, glucose, organic acids, and volatiles were analyzed in both recently prepared and stored pork samples. Storage resulted in increased levels of lactic acid bacteria and glucose-derived short chain alkyl volatiles, and a decrease in redox potential and volatile aldehyde levels. The addition of glucose to meat did not affect the biochemical characteristics of stored minced pork.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Food Preservatives); 0 (Volatile Organic Compounds); IY9XDZ35W2 (Glucose)


  9 / 102611 MEDLINE  
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PMID:28112488
Autor:Zhuang W; Liu X; Yang J; Wu J; Zhou J; Chen Y; Liu D; Ying H
Endereço:State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, No. 5, Xinmofan Road, Nanjing, 210009, China.
Título:Immobilization of Clostridium acetobutylicum onto natural textiles and its fermentation properties.
Fonte:Microb Biotechnol; 10(2):502-512, 2017 Mar.
ISSN:1751-7915
País de publicação:United States
Idioma:eng
Resumo:Immobilized fermentation has several advantages over traditional suspended fermentation, including simple and continuous operation, improved fermentation performance and reduced cost. Carrier is the most adjustable element among three elements of immobilized fermentation, including carrier, bacteria and environment. In this study, we characterized carrier roughness and surface properties of four types of natural fibres, including linen, cotton, bamboo fibre and silk, to assess their effects on cell immobilization, fermentation performance and stability. Linen with higher specific surface area and roughness could adsorb more bacteria during immobilized fermentation, thereby improving fermentation performance; thus, linen was selected as a suitable carrier and was applied for acetone-butanol-ethanol (ABE) fermentation. To further improve fermentation performance, we also found that microbes of Clostridium acetobutylicum were negatively charged surfaces during fermentation. Therefore, we then modified linen with polyetherimide (PEI) and steric acid (SA) to increase surface positive charge and improve surface property. During ABE fermentation, the adhesion between modified linen and bacteria was increased, adsorption was increased about twofold compared with that of unmodified linen, and butanol productivity was increased 8.16% and 6.80% with PEI- and SA-modified linen as carriers respectively.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Butanols); 1364PS73AF (Acetone); 3K9958V90M (Ethanol)


  10 / 102611 MEDLINE  
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PMID:28498333
Autor:Sousa E Silva FC; Tierno AF; Wengryniuk SE
Endereço:Department of Chemistry, Temple University, 1901 N. 13th St., Philadelphia, PA 19122, USA. tug08706@temple.edu.
Título:Hypervalent Iodine Reagents in High Valent Transition Metal Chemistry.
Fonte:Molecules; 22(5), 2017 May 12.
ISSN:1420-3049
País de publicação:Switzerland
Idioma:eng
Resumo:Over the last 20 years, high valent metal complexes have evolved from mere curiosities to being at the forefront of modern catalytic method development. This approach has enabled transformations complimentary to those possible via traditional manifolds, most prominently carbon-heteroatom bond formation. Key to the advancement of this chemistry has been the identification of oxidants that are capable of accessing these high oxidation state complexes. The oxidant has to be both powerful enough to achieve the desired oxidation as well as provide heteroatom ligands for transfer to the metal center; these heteroatoms are often subsequently transferred to the substrate via reductive elimination. Herein we will review the central role that hypervalent iodine reagents have played in this aspect, providing an ideal balance of versatile reactivity, heteroatom ligands, and mild reaction conditions. Furthermore, these reagents are environmentally benign, non-toxic, and relatively inexpensive compared to other inorganic oxidants. We will cover advancements in both catalysis and high valent complex isolation with a key focus on the subtle effects that oxidant choice can have on reaction outcome, as well as limitations of current reagents.
Tipo de publicação: JOURNAL ARTICLE; REVIEW
Nome de substância:0 (Coordination Complexes); 0 (Indicators and Reagents); 0 (Ligands); 0 (Transition Elements); 9679TC07X4 (Iodine)



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