313 research outputs found

    A comparison of experimental and numerical behaviour characteristics of a ship entering a lock using benchmark test data

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    This paper discusses several papers that were presented at the 3rd International Conference on Ship Manoeuvring in Shallow and Confined Water, which had a non-exclusive focus on Ship Behaviour in Locks. For this conference, experimental model test data obtained at Flanders Hydraulics Research had been made public and researchers were encouraged to compare numerical with experimental results [1]. Data of benchmark tests carried out both with self-propelled and captive models were used by researchers for comparison with various numerical tools. The objective of this paper is to give a selected overview of how accurately numerical tools are presently able to predict the hydrodynamic forces that occur on ships approaching locks. Based on this, the paper concludes that experiments and numerical tools complement each other

    Photovoltaic System Implementation in Baltra and Puerto Ayora Islands

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    In the research, an analysis of the impact of the photovoltaic systems installed in two islands of the Galápagos archipelago is made. In this sense, a series of calculations has been used to find the significant values that have allowed us to choose the specific devices for this project. A modeling study was analyzed to quantify the total energy of the system, the number of possible modules to be installed, the amount of energy to be stored according to the type of batteries and the ampere-hour (Ah) that the regulation set must support of the electric current. The socio-economic and environmental impact of the system on Baltra Island was assessed with an example and estimations to make it explicit, the results of the surveys used are shown through which the most significant results were exposed, exposing that the photovoltaic systems in stage of implantation do not affect the environment, flora and fauna, its greatest impact is in the use of land

    Photovoltaic System Implementation in Baltra and Puerto Ayora Islands

    Full text link
    In the research, an analysis of the impact of the photovoltaic systems installed in two islands of the Galápagos archipelago is made. In this sense, a series of calculations has been used to find the significant values that have allowed us to choose the specific devices for this project. A modeling study was analyzed to quantify the total energy of the system, the number of possible modules to be installed, the amount of energy to be stored according to the type of batteries and the ampere-hour (Ah) that the regulation set must support of the electric current. The socio-economic and environmental impact of the system on Baltra Island was assessed with an example and estimations to make it explicit, the results of the surveys used are shown through which the most significant results were exposed, exposing that the photovoltaic systems in stage of implantation do not affect the environment, flora and fauna, its greatest impact is in the use of land

    Transcriptome profiling of the small intestinal epithelium in germfree versus conventional piglets

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    <p>Abstract</p> <p>Background</p> <p>To gain insight into host-microbe interactions in a piglet model, a functional genomics approach was used to address the working hypothesis that transcriptionally regulated genes associated with promoting epithelial barrier function are activated as a defensive response to the intestinal microbiota. Cesarean-derived germfree (GF) newborn piglets were colonized with adult swine feces, and villus and crypt epithelial cell transcriptomes from colonized and GF neonatal piglets were compared using laser-capture microdissection and high-density porcine oligonucleotide microarray technology.</p> <p>Results</p> <p>Consistent with our hypothesis, resident microbiota induced the expression of genes contributing to intestinal epithelial cell turnover, mucus biosynthesis, and priming of the immune system. Furthermore, differential expression of genes associated with antigen presentation (pan SLA class I, <it>B2M</it>, <it>TAP1 </it>and <it>TAPBP</it>) demonstrated that microbiota induced immune responses using a distinct regulatory mechanism common for these genes. Specifically, gene network analysis revealed that microbial colonization activated both type I (IFNAR) and type II (IFNGR) interferon receptor mediated signaling cascades leading to enhanced expression of signal transducer and activator of transcription 1 (STAT1), STAT2 and IFN regulatory factor 7 (IRF7) transcription factors and the induction of IFN-inducible genes as a reflection of intestinal epithelial inflammation. In addition, activated RNA expression of NF-kappa-B inhibitor alpha (<it>NFκBIA</it>; a.k.a I-kappa-B-alpha, IKBα) and toll interacting protein (<it>TOLLIP</it>), both inhibitors of inflammation, along with downregulated expression of the immunoregulatory transcription factor GATA binding protein-1 (<it>GATA1</it>) is consistent with the maintenance of intestinal homeostasis.</p> <p>Conclusion</p> <p>This study supports the concept that the intestinal epithelium has evolved to maintain a physiological state of inflammation with respect to continuous microbial exposure, which serves to sustain a tight intestinal barrier while preventing overt inflammatory responses that would compromise barrier function.</p

    Inclusión de harinas de follajes arbóreos y arbustivos tropicales (morus alba; erythrina poeppigiana; tithonia diversifolia e hibiscus rosa-sinensis) en la alimentación de cuyes (cavia porcellus linnaeus)

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    La investigación se ejecutó en la Finca Experimental “La María” propiedad de la Universidad Técnica Estatal de Quevedo (UTEQ) localizada en el km 71/2 de la vía Quevedo-Mocache; Provincia de Los Ríos cuya ubicación geográfica de 1º 6’ 23” de latitud sur y 79º 29’ 12” de longitud oeste y a una altura de 73 msnm. El objetivo principal fue evaluar el comportamiento productivo con la inclusión del 20% de harinas arbustivas y arbóreas tropicales.  Se utilizaron 40 cuyes machos de 30 días de edad. Se empleó un diseño completamente al azar con cinco tratamientos, cuatro réplicas y la unidad experimental estuvo conformado por 2 cuyes. Para determinar las diferencias entre medias de tratamientos se aplicó la prueba de Tukey (P≤0,05). Se evaluaron cinco tratamientos en dietas de: (T0) dieta 100% balanceado, (T1) 80% dieta y 20% harina de Morus alba, (T2) 80% dieta y 20% harina de Erythrina poeppigiana, (T3) 80% dieta y 20% harina de Tithonia diversifolia, (T4) 80% dieta y 20% harina de Hibiscus rosa-sinensis. Las variables bajo estudio fueron: Consumo de alimento de balanceado en materia seca g (CABMS), ganancia de peso g (GP), índice de conversión alimenticia (ICA) y rendimiento a la canal % (RC). La rentabilidad de los tratamientos se la determinó a través de la relación beneficio-costo (R b/c). El mayor (P and lt;0,01) CABMS; GP-ICA; RC-Rentabilidad, la registraron los tratamientos: T0 (48,34 g MS animal-1 d-1); T1 (8,80 g animal-1 d-1 y 5,04) y el T3 (77,67% y 26,20%, respectivamente)

    Far-off and close-up dry matter intake modulate indicators of immunometabolic adaptations to lactation in subcutaneous adipose tissue of pasture-based transition dairy cows

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    The common practice of increasing dietary energy density during the close-up dry period (last ∼3 wk prepartum) has been recently associated with a higher incidence of metabolic disorders after calving. Despite these reports, over-feeding of metabolizable energy (ME) during the far-off, nonlactating period is a common management policy aimed at achieving optimum calving body condition score (BCS) in pasture-based systems, as cows are generally thinner than total mixed ration cows at the end of lactation. Our hypothesis was that both far-off and close-up overfeeding influence the peripartum adipose tissue changes associated with energy balance and inflammatory state. Sixty mid-lactation, grazing dairy cows of mixed age and breed were randomly allocated to 1 of 2 groups that were managed through late lactation to achieve a low and high BCS (approximately 4.25 and 5.0 on a 10-point scale) at dry-off. The low BCS cows were then overfed ME to ensure that they achieved the same BCS as the higher BCS group by calving. Within each rate of BCS gain treatment, cows were offered 65, 90, or 120% of their pre-calving ME requirements for 3 wk pre-calving in a 2 × 3 factorial arrangement of treatments (i.e., 10 cows/treatment). Subcutaneous adipose tissue was collected via biopsy at −1, 1, and 4 wk relative to parturition. Quantitative PCR was used to measure mRNA and microRNA expression of targets related to adipogenesis and inflammation. Cows overfed in the far-off period had increased expression of miR-143 and miR-378 prepartum (−1 wk) indicating greater adipogenesis, consistent with their rapid gain in BCS following dry-off. Furthermore, the lower postpartum expression of IL6, TNF, TLR4, TLR9, and miR-145, and a higher abundance of miR-99a indicated lower body fat mobilization in early lactation in the same group. In the close-up period, feeding either 65 or 120% of ME requirements caused changes in FASN, IL1B, IL6R, TLR9, and the microRNA miR-143, miR-155, and miR-378. Their respective expression patterns indicate a tentative negative-feedback mechanism in metabolically compromised, feed-restricted cows, and a possible immune-related stimulation of lipolysis in apparently static adipocytes in overfed cows. Data from cows fed 90% of ME requirements indicate the existence of a balance between lipolytic (inflammatory-related) and anti-lipolytic signals, to prime the mobilization machinery in light of imminent lactation. Overall, results indicate that far-off dry cow nutrition influences peripartum adipose tissue metabolism, with neither strategy negatively affecting the physiological adaptation to lactation. Furthermore, to ensure a favorable transition, cows should be subjected to a small feed restriction in the close-up period, irrespective of far-off nutritional management

    What is new in uremic toxicity?

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    Uremic syndrome results from a malfunctioning of various organ systems due to the retention of compounds which, under normal conditions, would be excreted into the urine and/or metabolized by the kidneys. If these compounds are biologically active, they are called uremic toxins. One of the more important toxic effects of such compounds is cardio-vascular damage. A convenient classification based on the physico-chemical characteristics affecting the removal of such compounds by dialysis is: (1) small water-soluble compounds; (2) protein-bound compounds; (3) the larger “middle molecules”. Recent developments include the identification of several newly detected compounds linked to toxicity or the identification of as yet unidentified toxic effects of known compounds: the dinucleotide polyphosphates, structural variants of angiotensin II, interleukin-18, p-cresylsulfate and the guanidines. Toxic effects seem to be typically exerted by molecules which are “difficult to remove by dialysis”. Therefore, dialysis strategies have been adapted by applying membranes with larger pore size (high-flux membranes) and/or convection (on-line hemodiafiltration). The results of recent studies suggest that these strategies have better outcomes, thereby clinically corroborating the importance attributed in bench studies to these “difficult to remove” molecules

    The amyloid imaging for the prevention of Alzheimer's disease consortium: A European collaboration with global impact

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    Background: Amyloid-β (Aβ) accumulation is considered the earliest pathological change in Alzheimer's disease (AD). The Amyloid Imaging to Prevent Alzheimer's Disease (AMYPAD) consortium is a collaborative European framework across European Federation of Pharmaceutical Industries Associations (EFPIA), academic, and ‘Small and Medium-sized enterprises’ (SME) partners aiming to provide evidence on the clinical utility and cost-effectiveness of Positron Emission Tomography (PET) imaging in diagnostic work-up of AD and to support clinical trial design by developing optimal quantitative methodology in an early AD population. The AMYPAD studies: In the Diagnostic and Patient Management Study (DPMS), 844 participants from eight centres across three clinical subgroups (245 subjective cognitive decline, 342 mild cognitive impairment, and 258 dementia) were included. The Prognostic and Natural History Study (PNHS) recruited pre-dementia subjects across 11 European parent cohorts (PCs). Approximately 1600 unique subjects with historical and prospective data were collected within this study. PET acquisition with [18F]flutemetamol or [18F]florbetaben radiotracers was performed and quantified using the Centiloid (CL) method. Results: AMYPAD has significantly contributed to the AD field by furthering our understanding of amyloid deposition in the brain and the optimal methodology to measure this process. Main contributions so far include the validation of the dual-time window acquisition protocol to derive the fully quantitative non-displaceable binding potential (BPND), assess the value of this metric in the context of clinical trials, improve PET-sensitivity to emerging Aβ burden and utilize its available regional information, establish the quantitative accuracy of the Centiloid method across tracers and support implementation of quantitative amyloid-PET measures in the clinical routine. Future steps: The AMYPAD consortium has succeeded in recruiting and following a large number of prospective subjects and setting up a collaborative framework to integrate data across European PCs. Efforts are currently ongoing in collaboration with ARIDHIA and ADDI to harmonize, integrate, and curate all available clinical data from the PNHS PCs, which will become openly accessible to the wider scientific community

    HIF-1 and SKN-1 Coordinate the Transcriptional Response to Hydrogen Sulfide in Caenorhabditis elegans

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    Hydrogen sulfide (H2S) has dramatic physiological effects on animals that are associated with improved survival. C. elegans grown in H2S are long-lived and thermotolerant. To identify mechanisms by which adaptation to H2S effects physiological functions, we have measured transcriptional responses to H2S exposure. Using microarray analysis we observe rapid changes in the abundance of specific mRNAs. The number and magnitude of transcriptional changes increased with the duration of H2S exposure. Functional annotation suggests that genes associated with protein homeostasis are upregulated upon prolonged exposure to H2S. Previous work has shown that the hypoxia-inducible transcription factor, HIF-1, is required for survival in H2S. In fact, we show that hif-1 is required for most, if not all, early transcriptional changes in H2S. Moreover, our data demonstrate that SKN-1, the C. elegans homologue of NRF2, also contributes to H2S-dependent changes in transcription. We show that these results are functionally important, as skn-1 is essential to survive exposure to H2S. Our results suggest a model in which HIF-1 and SKN-1 coordinate a broad transcriptional response to H2S that culminates in a global reorganization of protein homeostasis networks
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