1,152 research outputs found

    Más que siete mares, un océano

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    Se analiza la necesidad de conservación de los ecosistemas oceánicos mundiales, y la urgencia de crear áreas protegidas en mar abierto. Los siete mares inspiran imágenes de vastedad, de grandiosa expansión, de variedad y tolerancia casi infinitas. Siempre en el marco de la metáfora, este trabajo se aparta de la visión de los siete mares para apoyar a la de 'un solo océano'. En lenguaje más formal, el objetivo es promover el pensamiento ecosistémico integrado, difundir el mensaje de que el océano es uno, agotable, e incapaz de resisitir el abuso ambiental sostenido. El artículo incluye definiciones, información sobre el primer Ärea Marina Protegida (AMP) en Mar abierto en el Atlántico sudoccidental, Naumuncurá, Banco Burdwood y finaliza con otras lecturas sugeridas

    An E-mail Service in a Military Adolescent Medicine Clinic: will teens use it and what for?

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    The goal of this study was to determine utilization patterns of an Adolescent Medicine Clinic e-mail service. An e-mail service was offered to 6134 patients presenting for care to a military Adolescent Medicine Clinic in San Antonio, Texas over a 6-month period. Families had to complete an authorization form acknowledging that the e-mail service was not encrypted and was not to be used for emergent issues prior to use. 482 families signed up for the service. A total of 42 e-mails were received from 28 of these families. 75% of all e-mails were initiated by parents. The majority of e-mails were administrative issues including: medication refills, lab follow up, and referrals requests. In conclusion, the e-mail service was a low cost method to increase communication options for our patients that was not associated with a large increase in clinic workload because of low utilization rates, especially among younger adolescents.Keywords: Adolescents; E-mail; Internet; Electronic communication; Physicianpatient communicatio

    Electronic structure of REREAuMg and REREAgMg (RERE = Eu, Gd, Yb)

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    We have investigated the electronic structure of the equiatomic EuAuMg, GdAuMg, YbAuMg and GdAgMg intermetallics using x-ray photoelectron spectroscopy. The spectra revealed that the Yb and Eu are divalent while the Gd is trivalent. The spectral weight in the vicinity of the Fermi level is dominated by the mix of Mg ss, Au/Ag spsp and RERE spdspd bands, and not by the RERE 4f4f. We also found that the Au and Ag dd bands are extraordinarily narrow, as if the noble metal atoms were impurities submerged in a low density spsp metal host. The experimental results were compared with band structure calculations, and we found good agreement provided that the spin-orbit interaction in the Au an Ag dd bands is included and correlation effects in an open 4f4f shell are accounted for using the local density approximation + Hubbard UU scheme. Nevertheless, limitations of such a mean-field scheme to explain excitation spectra are also evident.Comment: 4 pages, 3 figures, Brief Repor

    Rationale and practical techniques for mouse models of early vein graft adaptations

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    Mouse models serve as relatively new yet powerful research tools to study intimal hyperplasia and wall remodeling of vein bypass graft failure. Several model variations have been reported in the past decade. However, the approach demands thoughtful preparation, selected sophisticated equipment, microsurgical technical expertise, advanced tissue processing, and data acquisition. This review compares several described models and aims (building on our personal experiences) to practically aid the investigators who want to utilize mouse models of vein graft failure.Clinical RelevanceSurgical revascularization via vein grafting offers immediate and often dramatic end organ benefit. However, substantial percentages of vein conduits placed develop stenosis or fail, often early. Mechanistic studies of the complex interplay between the biologic and physical forces that drive failure have been hampered by limited quantity and quality of clinical specimens, and the inability of systems such as computer models and cell culture to mimic the clinical circumstance. This review summarizes the power and limitations of mouse vein graft models, and it includes practical experience-based advice for researchers aiming to utilize this tool

    Reversal of endothelial dysfunction by nicotinamide mononucleotide via extracellular conversion to nicotinamide riboside

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    Nicotinamide mononucleotide (NMN) and nicotinamide riboside (NR) are effective substrates for NAD synthesis, which may act as vasoprotective agents. Here, we characterize the effects of NMN and NR on endothelial inflammation and dysfunction and test the involvement of CD73 in these effects. Materials and methods: The effect of NMN and NR on IL1β- or TNFα-induced endothelial inflammation (ICAM1 and vWF expression), intracellular NAD concentration and NAD-related enzyme expression (NAMPT, CD38, CD73), were studied in HAECs. The effect of NMN and NR on angiotensin II-induced impairment of endotheliumdependent vasodilation was analyzed in murine aortic rings. The involvement of CD73 in NMN and NR effects was tested using CD73 inhibitor-AOPCP, or CD73/^{-/-} mice. Results: 24 h-incubation with NMN and NR induced anti-inflammatory effects in HAEC stimulated by IL1β or TNFα, as evidenced by a reduction in ICAM1 and vWF expression. Effects of exogenous NMN but not NR was abrogated in the presence of AOPCP, that efficiently inhibited extracellular endothelial conversion of NMN to NR, without a significant effect on the metabolism of NMN to NA. Surprisingly, intracellular NAD concentration increased in HAEC stimulated by IL1β or TNFα and this effect was associated with upregulation of NAMPT and CD73, whereas changes in CD38 expression were less pronounced. NMN and NR further increased NAD in IL1β- stimulated HAECs and AOPCP diminished NMN-induced increase in NAD, without an effect on NR-induced response. In ex vivo aortic rings stimulated with angiotensin II for 24 h, NO-dependent vasorelaxation induced by acetylcholine was impaired. NMN and NR, both prevented Ang II-induced endothelial dysfunction in the aorta. In aortic rings taken from CD73/^{-/-} mice NMN effect was lost, whereas NR effect was preserved. Conclusion: NMN and NR modulate intracellular NAD content in endothelium, inhibit endothelial inflammation and improve NO-dependent function by CD73-dependent and independent pathways, respectively. Extracellular conversion of NMN to NR by CD73 localized in the luminal surface of endothelial cells represent important vasoprotective mechanisms to maintain intracellular NAD

    Metabolomics reveals distinct neurochemical profiles associated with stress resilience

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    Acute social defeat represents a naturalistic form of conditioned fear and is an excellent model in which to investigate the biological basis of stress resilience. While there is growing interest in identifying biomarkers of stress resilience, until recently, it has not been feasible to associate levels of large numbers of neurochemicals and metabolites to stress-related phenotypes. The objective of the present study was to use an untargeted metabolomics approach to identify known and unknown neurochemicals in select brain regions that distinguish susceptible and resistant individuals in two rodent models of acute social defeat. In the first experiment, male mice were first phenotyped as resistant or susceptible. Then, mice were subjected to acute social defeat, and tissues were immediately collected from the ventromedial prefrontal cortex (vmPFC), basolateral/central amygdala (BLA/CeA), nucleus accumbens (NAc), and dorsal hippocampus (dHPC). Ultra-high performance liquid chromatography coupled with high resolution mass spectrometry (UPLC-HRMS) was used for the detection of water-soluble neurochemicals. In the second experiment, male Syrian hamsters were paired in daily agonistic encounters for 2 weeks, during which they formed stable dominant-subordinate relationships. Then, 24 h after the last dominance encounter, animals were exposed to acute social defeat stress. Immediately after social defeat, tissue was collected from the vmPFC, BLA/CeA, NAc, and dHPC for analysis using UPLC-HRMS. Although no single biomarker characterized stress-related phenotypes in both species, commonalities were found. For instance, in both model systems, animals resistant to social defeat stress also show increased concentration of molecules to protect against oxidative stress in the NAc and vmPFC. Additionally, in both mice and hamsters, unidentified spectral features were preliminarily annotated as potential targets for future experiments. Overall, these findings suggest that a metabolomics approach can identify functional groups of neurochemicals that may serve as novel targets for the diagnosis, treatment, or prevention of stress-related mental illness

    Mediation of smoking-associated postoperative mortality by perioperative complications in veterans undergoing elective surgery: data from Veterans Affairs Surgical Quality Improvement Program (VASQIP)--a cohort study

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    OBJECTIVE: To assess the mediation of smoking-associated postoperative mortality by postoperative complications. DESIGN: Observational cohort study. SETTING: Using data from the Veterans Affairs (VA) Surgical Quality Improvement Programme, a quality assurance programme for major surgical procedures in the VA healthcare system, we assessed the association of current smoking at the time of the surgery with 6-month and 1-year mortality. PRIMARY AND SECONDARY OUTCOME MEASURES: Using mediation analyses, we calculated the relative contribution of each smoking-associated complication to smoking-associated postoperative mortality, both unadjusted and adjusted for age, race/ethnicity, work relative value unit of the operation, surgeon specialty, American Society of Anesthesiologists class and year of surgery. Smoking-associated complications included surgical site infection (SSI), cardiovascular complications (myocardial infarction, cardiac arrest and/or stroke) and pulmonary complications (pneumonia, failure to wean and/or reintubation). RESULTS: There were 186 632 never smokers and 135 741 current smokers. The association of smoking and mortality was mediated by smoking-related complications with varying effects. In unadjusted analyses, the proportions of mediation of smoking to 6-month mortality explained by the complications were as follows: SSIs 22%, cardiovascular complications 12% and pulmonary complications 89%. In adjusted analyses, the per cents mediated by each complication were as follows: SSIs 2%, cardiovascular complications 4% and pulmonary complications 22%. In adjusted analyses for 1-year mortality, respective per cents mediated were 2%, 3% and 16%. CONCLUSIONS: Pulmonary complications, followed by cardiovascular complications and SSIs were mediators of smoking-associated 6-month and 1-year mortality. Interventions targeting smoking cessation and prevention and early treatment of pulmonary complications has the likelihood of reducing postoperative mortality after elective surgery

    Urea Is Both a Carbon and Nitrogen Source for Microcystis aeruginosa: Tracking 13C Incorporation at Bloom pH Conditions

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    The use of urea as a nitrogenous fertilizer has increased over the past two decades, with urea itself being readily detected at high concentrations in many lakes. Urea has been linked to cyanobacterial blooms as it is a readily assimilated nitrogen (N) - source for cyanobacteria that possess the enzyme urease. We tested the hypothesis that urea may also act as a carbon (C) source to supplemental growth requirements during the alkaline conditions created by dense cyanobacterial blooms, when concentrations of dissolved CO2 are vanishingly low. High rates of photosynthesis markedly reduce dissolved CO2 concentrations and drive up pH. This was observed in Lake Erie during the largest bloom on record (2015) over long periods (months) and short periods (days) of time, suggesting blooms experience periods of CO2-limitation on a seasonal and daily basis. We used 13C-urea to demonstrate that axenic cultures of the model toxic cyanobacterium, Microcystis aeruginosaNIES843, assimilated C at varying environmentally relevant pH conditions directly into a spectrum of metabolic pools during urea hydrolysis. Primarily, 13C from urea was assimilated into central C metabolism and amino acid biosynthesis pathways, including those important for the production of the hepatotoxin, microcystin, and incorporation into these pathways was at a higher percentage during growth at higher pH. This corresponded to increased growth rates on urea as the sole N source with increasing pH. We propose this ability to incorporate C from urea represents yet another competitive advantage for this cyanobacterium during dense algal blooms

    Testing the performance of a blind burst statistic

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    In this work we estimate the performance of a method for the detection of burst events in the data produced by interferometric gravitational wave detectors. We compute the receiver operating characteristics in the specific case of a simulated noise having the spectral density expected for Virgo, using test signals taken from a library of possible waveforms emitted during the collapse of the core of Type II Supernovae.Comment: 8 pages, 6 figures, Talk given at the GWDAW2002 worksho

    Synthesis, biophysical characterization and anti-HIV activity of d(TG3AG) Quadruplexes bearing hydrophobic tails at the 5'-end

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    Novel conjugated G-quadruplex-forming d(TG3AG) oligonucleotides, linked to hydrophobic groups through phosphodiester bonds at 50-end, have been synthesized as potential anti-HIV aptamers, via a fully automated, online phosphoramidite-based solid-phase strategy. Conjugated quadruplexes showed pronounced anti-HIV activity with some preference for HIV-1, with inhibitory activity invariably in the low micromolar range. The CD and DSC monitored thermal denaturation studies on the resulting quadruplexes, indicated the insertion of lipophilic residue at the 50-end, conferring always improved stability to the quadruplex complex (20 < DTm < 40 C). The data suggest no direct functional relationship between the thermal stability and anti-HIV activity of the folded conjugated G-quartets. It would appear that the nature of the residue at 50 end of the d(TG3AG) quadruplexes plays an important role in the thermodynamic stabilization but a minor influence on the anti-HIV activity. Moreover, a detailed CD and DSC analyses indicate a monophasic behaviour for sequences I and V, while for ODNs (II–IV) clearly show that these quadruplex structures deviate from simple two-state melting, supporting the hypothesis that intermediate states along the dissociation pathway may exis
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