3,982 research outputs found
PROPIEDADES BIOLÓGICAS DE PÉPTIDOS DERIVADOS DEL COLÁGENO DE ORGANISMOS MARINOS
Las especies marinas, así como los subproductos generados a partir de su industrialización representan una valiosa fuente de proteínas, entre las que se encuentra el colágeno. Típicamente, el colágeno se utiliza para la elaboración de gelatina, alimentos funcionales, películas para fotografía, empaques biodegradables, productos de cosmetología, entre otros. Sin embargo, otra forma de aprovechamiento poco explorada y novedosa de este material es la obtención de péptidos con actividad biológica (PABs). Los PABs derivados del colágeno y gelatina a partir de especies marinas tienen un enorme potencial, debido a que poseen excelentes propiedades biológicas, tales como antioxidantes, antihipertensivas, anticancerígenas, antimicrobianas, neuroprotectoras, así como inducir el crecimiento de tejido óseo y retardar el envejecimiento de la piel, propiedades que se han asociado frecuentemente a la presencia de aminoácidos prolina e hidroxiprolina en la secuencia del péptido y ciertas características estructurales. El presente trabajo recopila los hallazgos más recientes sobre los efectos benéficos de los PABs derivados de colágeno y gelatina de especies marinas, con énfasis en las características estructurales que definen sus propiedades antioxidantes, antihipertensivas, anticancerígenas y antimicrobianas
Reactivity of chlorodimethylsilyl-η5-cyclopentadienyltrichlorotitanium\ud with nitrogen based donors. X-ray molecular structure of\ud [Ti{η5-C5H4SiMe2[η1-N(2,6-Me2C6H3)]}Cl2]
This paper reports the reactivity of [Ti(η5-C5H4SiMe2Cl)Cl3], 1 towards nitrogen based donor reagents. Complex 1 reacts with lithium benzamidinato Li[PhC(NSiMe3)2] to afford [Ti(η5-C5H4SiMe2Cl){PhC(NSiMe3)2}Cl2] 2 and with lithium amide LiNMe2 to produce [Ti(η5-C5H4SiMe2NMe2)(NMe2)3] 3. The latter compound was converted into the dihalide derivatives [Ti(η5-C5H4SiMe2NMe2)(NMe2)X2] [X=Cl (4) and Br (5)] by reaction with SiMe3X (X=Cl or Br, respectively). The constrained geometry derivatives [Ti{η5-C5H4SiMe2(η1-NR)}Cl2] (R=C6H56, 2,6-Me2C6H37 and 2-Me-6-iPr-C6H38) have been synthesized by treatment of 1 with the corresponding primary aryl amines H2NR. Complex 7 was readily converted into the dialkyl and diamido compounds [Ti{η5-C5H4SiMe2[η1-N(C6H3Me2)]}X2] (X=Me (9), CH2Ph (10), CH2SiMe3 (11) or NMe2 (13)) by metathesis using Grignard or organolithium reagents and into the monoalkyl derivative [Ti{η5-C5H4SiMe2[η1-N(C6H3Me2)]}MeCl] (12) by reaction with AlMe3. The molecular structure of complex 7 [Ti{(η5-C5H4SiMe2[η1-N(2,6-Me2C6H3)]}Cl2] was established by X-ray crystallography.We are grateful to the DGICYT (Project PB-92-0178-C) and University of Alcalá for financial support of this research
Distribution of epicatechin metabolites in lymphoid tissues and testes of young rats with a cocoa-enriched diet
An increasing number of scientific studies support that flavanol-rich foods and beverages such as cocoa can promote human health, and are beneficial agents for the prevention of some diseases. Our previous studies showed that long-term cocoa intake enhances the antioxidant status in lymphoid organs and also modulates lymphocyte functionality in healthy young rats. Cocoa polyphenolic antioxidants seem to be the best candidates for those effects. However, data regarding polyphenol metabolites in tissues after a long-term cocoa intake are scarce. In the present study we mainly focus on the uptake and accumulation of epicatechin metabolites in lymphoid organs, including the thymus, spleen and mesenteric lymphoid nodes, as well as in the liver and testes after a diet rich in cocoa. Ten young weaned Wistar rats were fed randomly with a 10 % (w/w) cocoa diet or a control diet for 3 weeks, corresponding to their infancy and youth. Tissues were treated with a solid-phase extraction and analysed by liquid chromatography-tandem MS. The major compounds recovered in these tissues were glucuronide derivatives of epicatechin and methylepicatechin. The highest concentration of these metabolites was found in the thymus, testicles and liver, followed by lymphatic nodes and spleen. The high amount of epicatechin metabolites found in the thymus supports our previous findings showing its high antioxidant capacity compared with other tissues such as the spleen. Moreover, this is the first time that epicatechin metabolites have been found in high concentrations in the testes, confirming other studies that have suggested the testes as an important site of oxidation
Mycophenolic acid interferes the transcriptional regulation and protein trafficking of maturation surface markers in dendritic cells
Background: The ability of dendritic cells (DCs) to regulate adaptive immunity makes them interesting cells to be used as therapeutic targets modulating alloimmune responses. Mycophenolic acid (MPA) is an immunosuppressor commonly used in transplantation, and its effect on DCs has not been fully investigated. Methods: Monocyte-derived DCs were obtained from healthy volunteers and cultured for 7 days. Cells were treated with MPA on day 2 and matured by lipopolysaccharide (LPS) stimulation. Functionality of mature DC (mDCs) was evaluated by allogeneic mixed lymphocytes reaction. Surface expression of maturation markers (CD40, CD83, CD86, and ICAM-1) was analysed in both immature DCs (iDCs) and mDCs by flow cytometry. To assess transcriptional regulation and protein subcellular location, RT-PCR and confocal microscopy were used, respectively. Results: MPA decreased surface expression of all maturation markers in mDCs and significantly abrogated DCs-induced allogeneic T-cell proliferation after MPA pre-treatment. In iDCs, the reduced surface protein expression after MPA paralleled with mRNA downregulation of their genes. In mDCs, the mRNA levels of ICAM-1, CD40 and CD83 were enhanced in MPA-treated mDCs with an increase in the expression of CD83 and ICAM-1 near the Golgi compared to non-treated mDCs. In contrast, mRNA levels of CD86 were diminished after MPA treatment. Conclusions: The reduced surface markers expression in mDCs exerted by MPA produced a decline in their capacity to activate immune responses. Moreover, the inhibition of guanosine-derived nucleotide biosynthesis by MPA treatment leads to DC maturation interference by two mechanisms depending on the marker, transcriptional downregulation or disrupted intracellular protein trafficking
Quantum Fluctuation Theorems
Recent advances in experimental techniques allow one to measure and control
systems at the level of single molecules and atoms. Here gaining information
about fluctuating thermodynamic quantities is crucial for understanding
nonequilibrium thermodynamic behavior of small systems. To achieve this aim,
stochastic thermodynamics offers a theoretical framework, and nonequilibrium
equalities such as Jarzynski equality and fluctuation theorems provide key
information about the fluctuating thermodynamic quantities. We review the
recent progress in quantum fluctuation theorems, including the studies of
Maxwell's demon which plays a crucial role in connecting thermodynamics with
information.Comment: As a chapter of: F. Binder, L. A. Correa, C. Gogolin, J. Anders, and
G. Adesso (eds.), "Thermodynamics in the quantum regime - Fundamental Aspects
and New Directions", (Springer International Publishing, 2018
Enhancing European capabilities for application of multi-omics studies in biology and biomedicine space research
Following on from the NASA twins’ study, there has been a tremendous interest in the use of omics techniques in spaceflight. Individual space agencies, NASA's GeneLab, JAXA's ibSLS, and the ESA-funded Space Omics Topical Team and the International Standards for Space Omics Processing (ISSOP) groups have established several initiatives to support this growth. Here, we present recommendations from the Space Omics Topical Team to promote standard application of space omics in Europe. We focus on four main themes: i) continued participation in and coordination with international omics endeavors, ii) strengthening of the European space omics infrastructure including workforce and facilities, iii) capitalizing on the emerging opportunities in the commercial space sector, and iv) capitalizing on the emerging opportunities in human subjects research
GAPS-megacities: A new global platform for investigating persistent organic pollutants and chemicals of emerging concern in urban air
A pilot study was initiated in 2018 under the Global Atmospheric Passive Sampling (GAPS) Network named GAPS-Megacities. This study included 20 megacities/major cities across the globe with the goal of better understanding and comparing ambient air levels of persistent organic pollutants and other chemicals of emerging concern, to which humans residing in large cities are exposed. The first results from the initial period of sampling are reported for 19 cities for several classes of flame retardants (FRs) including organophosphate esters (OPEs), polybrominated diphenyl ethers (PBDEs), and halogenated flame retardants (HFRs) including new flame retardants (NFRs), tetrabromobisphenol A (TBBPA) and hexabromocyclododecane (HBCDD). The two cities, New York (USA) and London (UK) stood out with ∼3.5 to 30 times higher total FR concentrations as compared to other major cities, with total concentrations of OPEs of 15,100 and 14,100 pg/m, respectively. Atmospheric concentrations of OPEs significantly dominated the FR profile at all sites, with total concentrations in air that were 2–5 orders of magnitude higher compared to other targeted chemical classes. A moderately strong and significant correlation (r = 0.625, p < 0.001) was observed for Gross Domestic Product index of the cities with total OPEs levels. Although large differences in FR levels were observed between some cities, when averaged across the five United Nations regions, the FR classes were more evenly distributed and varied by less than a factor of five. Results for Toronto, which is a ‘reference city’ for this study, agreed well with a more in-depth investigation of the level of FRs over different seasons and across eight sites representing different urban source sectors (e.g. traffic, industrial, residential and background). Future sampling periods under this project will investigate trace metals and other contaminant classes, linkages to toxicology, non-targeted analysis, and eventually temporal trends. The study provides a unique urban platform for evaluating global exposome.A global study across 20 megacities/major cities reporting urban air concentrations of flame retardants and plasticizers.Authors thank the United Nations Environment Programme
(UNEP) and the Chemicals Management Plan (CMP) for financial
support. The worldwide implementation of the Global Monitoring
Plan is made possible thanks to the generous contributions to the
Stockholm Convention Voluntary Trust Fund from the Governments
of Japan, Norway, Sweden, and through the European
Commission’s Thematic Programme for Environment andSustainable Management of Natural Resources, including Energy
(ENRTP). Further, the contribution of the projects to support POPs
monitoring activities in regions, funded through the Global Environment
Facility (GEF) and the Strategic Approach to International
Chemicals Management (SAICM), is greatly acknowledged. Monitoring
activities and data collection and analysis are implemented
in the five UN regions in cooperation with strategic partners and
through the involvement of Regional Organization Groups and
Global Coordination Group.
We also thank Yasuyuki Shibata and Yoshikatsu Takazawa
(Tokyo, Japan); Juan Mu~noz-Arnanz (Madrid, Spain) and Dilek
€Ozkan and Sinan Kızıltug (_Istanbul, Turkey) for their help and
assistance in the sampling campaign
GAPS-megacities: A new global platform for investigating persistent organic pollutants and chemicals of emerging concern in urban air
A pilot study was initiated in 2018 under the Global Atmospheric Passive Sampling (GAPS) Network named GAPS-Megacities. This study included 20 megacities/major cities across the globe with the goal of better understanding and comparing ambient air levels of persistent organic pollutants and other chemicals of emerging concern, to which humans residing in large cities are exposed. The first results from the initial period of sampling are reported for 19 cities for several classes of flame retardants (FRs) including organophosphate esters (OPEs), polybrominated diphenyl ethers (PBDEs), and halogenated flame retardants (HFRs) including new flame retardants (NFRs), tetrabromobisphenol A (TBBPA) and hexabromocyclododecane (HBCDD). The two cities, New York (USA) and London (UK) stood out with ∼3.5 to 30 times higher total FR concentrations as compared to other major cities, with total concentrations of OPEs of 15,100 and 14,100 pg/m3, respectively. Atmospheric concentrations of OPEs significantly dominated the FR profile at all sites, with total concentrations in air that were 2-5 orders of magnitude higher compared to other targeted chemical classes. A moderately strong and significant correlation (r = 0.625, p < 0.001) was observed for Gross Domestic Product index of the cities with total OPEs levels. Although large differences in FR levels were observed between some cities, when averaged across the five United Nations regions, the FR classes were more evenly distributed and varied by less than a factor of five. Results for Toronto, which is a "reference city" for this study, agreed well with a more in-depth investigation of the level of FRs over different seasons and across eight sites representing different urban source sectors (e.g. traffic, industrial, residential and background). Future sampling periods under this project will investigate trace metals and other contaminant classes, linkages to toxicology, non-targeted analysis, and eventually temporal trends. The study provides a unique urban platform for evaluating global exposome.Fil: Saini, Amandeep. Environment and Climate Change; CanadáFil: Harner, Tom. Environment and Climate Change; CanadáFil: Chinnadhurai, Sita. Environment and Climate Change; CanadáFil: Schuster, Jasmin K.. Environment and Climate Change; CanadáFil: Yates, Alan. Environment and Climate Change; CanadáFil: Sweetman, Andrew. Lancaster Environment Centre; Reino UnidoFil: Aristizabal Zuluaga, Beatriz H.. Universidad Nacional de Colombia; ColombiaFil: Jiménez, Begoña. Consejo Superior de Investigaciones Científicas; EspañaFil: Manzano, Carlos A.. Universidad de Chile; ChileFil: Gaga, Eftade O.. Eskisehir Technical University; TurquíaFil: Stevenson, Gavin. National Measurement Institute; AustraliaFil: Falandysz, Jerzy. Uniwersytet Gdanski; PoloniaFil: Ma, Jianmin. Peking University; ChinaFil: Miglioranza, Karina Silvia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Kannan, Kurunthachalam. Nyu Grossman School Of Medicine; Estados UnidosFil: Tominaga, Maria. Sao Paulo State Environmental Company; BrasilFil: Jariyasopit, Narumol. No especifíca;Fil: Rojas, Nestor Y.. Universidad Nacional de Colombia; ColombiaFil: Amador-Muñoz, Omar. Universidad Nacional Autónoma de México; MéxicoFil: Sinha, Ravindra. Patna University; IndiaFil: Alani, Rose. University of Lagos; NigeriaFil: Suresh, R.. No especifíca;Fil: Nishino, Takahiro. Tokyo Metropolitan Research Institute for Environmental Protection; JapónFil: Shoeib, Tamer. American University In Cairo; Egipt
Carbon fluxes resulting from land-use changes in the Tamaulipan thornscrub of northeastern Mexico
Information on carbon stock and flux resulting from land-use changes in subtropical, semi-arid ecosystems are important to understand global carbon flux, yet little data is available. In the Tamaulipan thornscrub forests of northeastern Mexico, biomass components of standing vegetation were estimated from 56 quadrats (200 m2 each). Regional land-use changes and present forest cover, as well as estimates of soil organic carbon from chronosequences, were used to predict carbon stocks and fluxes in this ecosystem
Induction Chemotherapy Followed by Radiotherapy versus Concurrent Chemoradiotherapy in elderly patients with nasopharyngeal carcinoma: finding from a propensity-matched analysis
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