192 research outputs found

    Production of mexican brown macroalgae fucoidan and fucosidases under an integral green technology bioproceses by the biorefinery concept

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    Marine ecosystem can be considered a rather exploited source of natural substances with enormous bioactive potential. In Mexico macro-algae study remain forgotten for research and economic purposes besides the high amount of this resource along the west and east coast. For that reason the Bioferinery Group of the Autonomous University of Coahuila, have been studying the biorefinery concept in order to recover high value byproducts of Mexican brown macro-algae including polysaccharides and enzymes to be applied in food, pharmaceutical and energy industry. Brown macroalgae are an important source of fucoidan, alginate and laminarin which comprise a complex group of macromolecules with a wide range of important biological properties such as anticoagulant, antioxidant, antitumoral and antiviral and also as rich source of fermentable sugars for enzymes production. Additionally, specific enzymes able to degrade algae matrix (fucosidases, sulfatases, aliginases, etc) are important tools to establish structural characteristics and biological functions of these polysaccharides. The aims of the present work were the integral study of bioprocess for macroalgae biomass exploitation by the use of green technologies as hydrothermal extraction and solid state fermentation in order to produce polysaccharides and enzymes (fucoidan and fucoidan hydrolytic enzymes). This work comprises the use of the different bioprocess phases in order to produce high value products with lower time and wastes

    Correlation between microstructure and temperature dependence of magnetic properties in Fe 60 Co 18 ( Nb , Zr ) 6 B 15 Cu 1 alloy series

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    Temperature dependence of magnetic properties of nanocrystalline Fe60Co18Cu1B15Nb6−xZrx (x =0, 3, 6) alloys has been studied at different stages of devitrification. Transmission electron microscopy shows nanocrystals of the size ïżœ5 nm, which remains almost constant along the nanocrystallization process. Curie temperature of the residual amorphous phase decreases as nanocrystallization progresses for all the studied alloys. Thermal dependence of the exchange stiffness constant is obtained from the measurement of specific magnetization and coercivity as a function of crystalline fraction and temperature for the three studied alloys

    Magneto-caloric effect in the pseudo-binary intermetallic YPrFe17 compound

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    We have synthesized the intermetallic YPrFe17 compound by arc-melting. X-ray and neutron powder diffraction show that the crystal structure is rhombohedral with View the MathML source space group (Th2Zn17-type). The investigated compound exhibits a broad isothermal magnetic entropy change {\Delta}SM(T) associated with the ferro-to-paramagnetic phase transition (TC \approx 290 K). The |{\Delta}SM| (\approx 2.3 J kg-1 K-1) and the relative cooling power (\approx 100 J kg-1) have been calculated for applied magnetic field changes up to 1.5 T. A single master curve for {\Delta}SM under different values of the magnetic field change can be obtained by a rescaling of the temperature axis. The results are compared and discussed in terms of the magneto-caloric effect in the isostructural R2Fe17 (R = Y, Pr and Nd) binary intermetallic alloys.Comment: Preprint, 5 pages (postprint), 4 figures, regular pape

    RNA Polymerase II CTD phosphatase Rtr1 fine-tunes transcription termination

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    RNA Polymerase II (RNAPII) transcription termination is regulated by the phosphorylation status of the C-terminal domain (CTD). The phosphatase Rtr1 has been shown to regulate serine 5 phosphorylation on the CTD; however, its role in the regulation of RNAPII termination has not been explored. As a consequence of RTR1 deletion, interactions within the termination machinery and between the termination machinery and RNAPII were altered as quantified by Disruption-Compensation (DisCo) network analysis. Of note, interactions between RNAPII and the cleavage factor IA (CF1A) subunit Pcf11 were reduced in rtr1Δ, whereas interactions with the CTD and RNA-binding termination factor Nrd1 were increased. Globally, rtr1Δ leads to decreases in numerous noncoding RNAs that are linked to the Nrd1, Nab3 and Sen1 (NNS) -dependent RNAPII termination pathway. Genome-wide analysis of RNAPII and Nrd1 occupancy suggests that loss of RTR1 leads to increased termination at noncoding genes. Additionally, premature RNAPII termination increases globally at protein-coding genes with a decrease in RNAPII occupancy occurring just after the peak of Nrd1 recruitment during early elongation. The effects of rtr1Δ on RNA expression levels were lost following deletion of the exosome subunit Rrp6, which works with the NNS complex to rapidly degrade a number of noncoding RNAs following termination. Overall, these data suggest that Rtr1 restricts the NNS-dependent termination pathway in WT cells to prevent premature termination of mRNAs and ncRNAs. Rtr1 facilitates low-level elongation of noncoding transcripts that impact RNAPII interference thereby shaping the transcriptome

    Can Breast Tumors Affect the Oxidative Status of the Surrounding Environment? A Comparative Analysis among Cancerous Breast, Mammary Adjacent Tissue, and Plasma

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    In this paper, we investigated the oxidative profile of breast tumors in comparison with their normal adjacent breast tissue. Our study indicates that breast tumors present enhanced oxidative/nitrosative stress, with concomitant augmented antioxidant capacity when compared to the adjacent normal breast. These data indicate that breast cancers may be responsible for the induction of a prooxidant environment in the mammary gland, in association with enhanced TNF-α and nitric oxide

    Lung volume calculated from electrical impedance tomography in ICU patients at different PEEP levels

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    Purpose: To study and compare the relationship between end-expiratory lung volume (EELV) and changes in end-expiratory lung impedance (EELI) measured with electrical impedance tomography (EIT) at the basal part of the lung at different PEEP levels in a mixed ICU population. Methods: End-expiratory lung volume, EELI and tidal impedance variation were determined at four PEEP levels (15-10-5-0 cm H2O) in 25 ventilated ICU patients. The tidal impedance variation and tidal volume at 5 cm H2O PEEP were used to calculate change in impedance per ml; this ratio was then used to calculate change in lung volume from change in EELI. To evaluate repeatability, EELV was measured in quadruplicate in five additional patients. Results: There was a significant but relatively low correlation (r = 0.79; R2= 0.62) and moderate agreement (bias 194 ml, SD 323 ml) between ΔEELV and change in lung volume calculated from the ΔEELI. The ratio of tidal impedance variation and tidal volume differed between patients and also varied at different PEEP levels. Good agreement was found between repeated EELV measurements and washin/washout of a simulated nitrogen washout technique. Conclusion: During a PEEP trial, the assumption of a linear relationship between change in global tidal impedance and tidal volume cannot be used to calculate EELV when impedance is measured at only one thoracic level just above the diaphragm

    "We live from mother nature":neoliberal globalization, commodification, the 'war on drugs', and biodiversity in Colombia since the 1990s

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    This article explores how macroeconomic and environmental policies instituted since the 1990s have altered meanings, imaginaries, and the human relationship to nature in Colombia. The Colombian nation-state is pluri-ethnic, multilingual, and megabiodiverse. In this context, indigenous peoples, Afro-Colombians, and some peasant communities survive hybridization of their cultures. They have developed their own ways of seeing, understanding, and empowering the world over centuries of European rule. However, threats to relatively discrete cultural meanings have increased since major changes in the 1990s, when Colombia experienced the emergence of new and modern interpretations of nature, such as “biodiversity,” and a deepening of globalized neoliberal economic and political management. These policies involve a modern logic of being in the world, the establishment of particular regulatory functions for economies, societies, and the environment, and their spread has been facilitated by webs of political and economic power. We trace their local effects with reference to three indigenous groups

    Impact of clerkship in the attitudes toward psychiatry among Portuguese medical students

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    <p>Abstract</p> <p>Background</p> <p>Given the shortage of human resources and the launching of a new Mental Health Plan, recruitment of psychiatrists is currently a major concern in Portugal, as well as in several other countries. Medical students' attitude toward psychiatry has been pointed as a predictor of recruitment. This study aims to evaluate the medical students' perception of psychiatry before and after a clerkship, and the impact on their intention to pursue psychiatry as a future specialty option.</p> <p>Methods</p> <p>Two self-report questionnaires were administered to all 6<sup>th </sup>year students in a medical school in Lisbon, before and after a 4-weeks full-time psychiatric clerkship, in order to evaluate attitudes toward psychiatry and intention to follow psychiatry in the future. Statistical analysis included Wilcoxon and Chi-square tests.</p> <p>Results</p> <p>153 students (60.8% female) filled in both questionnaires (no dropouts). After the clerkship, there was a significant improvement regarding the overall merits of psychiatry, efficacy, role definition and functioning of psychiatrists, use of legal powers to hospitalize patients and specific medical school factors. There was also a significant increase of students decided or considering the possibility to take a residency in psychiatry.</p> <p>However, perceptions of low prestige and negative pressure from family and peers regarding a future choice of psychiatry remained unchanged in about one-third of the students.</p> <p>Conclusions</p> <p>The results indicate clearly that the clerkship had a favorable overall impact on the student attitude towards psychiatry, as well as in the number of students considering a future career in psychiatry. Attitudes toward psychiatry seems a promising outcome indicator of the clerkship's quality, but further research is needed in order to assess its reliability as a sound predictor of recruitment.</p

    Factors affecting residency rank-listing: A Maxdiff survey of graduating Canadian medical students

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    <p>Abstract</p> <p>Background</p> <p>In Canada, graduating medical students consider many factors, including geographic, social, and academic, when ranking residency programs through the Canadian Residency Matching Service (CaRMS). The relative significance of these factors is poorly studied in Canada. It is also unknown how students differentiate between their top program choices. This survey study addresses the influence of various factors on applicant decision making.</p> <p>Methods</p> <p>Graduating medical students from all six Ontario medical schools were invited to participate in an online survey available for three weeks prior to the CaRMS match day in 2010. Max-Diff discrete choice scaling, multiple choice, and drop-list style questions were employed. The Max-Diff data was analyzed using a scaled simple count method. Data for how students distinguish between top programs was analyzed as percentages. Comparisons were made between male and female applicants as well as between family medicine and specialist applicants; statistical significance was determined by the Mann-Whitney test.</p> <p>Results</p> <p>In total, 339 of 819 (41.4%) eligible students responded. The variety of clinical experiences and resident morale were weighed heavily in choosing a residency program; whereas financial incentives and parental leave attitudes had low influence. Major reasons that applicants selected their first choice program over their second choice included the distance to relatives and desirability of the city. Both genders had similar priorities when selecting programs. Family medicine applicants rated the variety of clinical experiences more importantly; whereas specialty applicants emphasized academic factors more.</p> <p>Conclusions</p> <p>Graduating medical students consider program characteristics such as the variety of clinical experiences and resident morale heavily in terms of overall priority. However, differentiation between their top two choice programs is often dependent on social/geographic factors. The results of this survey will contribute to a better understanding of the CaRMS decision making process for both junior medical students and residency program directors.</p
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