Influencia del ángulo de incidencia en el retemblado en procesos de torneado

El presente trabajo estudia el fenómeno del retemblado en un proceso de corte de metal. El efecto del roce entre la herramienta de corte y el material de trabajo es parcialmente explicado utilizando un modelo matemático. La influencia del ángulo de incidencia de la herramienta en el proceso de corte de metal es analizada experimentalmente a través de diagramas de estabilidad

Differences in the fly-load of Haematobia irritans (Diptera: Muscidae) on cattle is modified by endophyte infection of pastures

Background: The horn fly, Haematobia irritans, is an obligate bloodsucking ectoparasite of pastured cattle and is a major pest of livestock production in North and South America and Europe. In this study, we investigated the potential to use cattle pastures, infected with non-toxic, "friendly" fungal-endophyte-infected (E+) tall fescue, Festuca arundinacea Schreb., as a strategy for reducing horn fly loads in cattle, and to evaluate the possible bioinsecticide effect on horn fly larvae. Results: When cattle grazed in E+ tall fescue, a decrease in fly-load was observed, compared with other pastures (endophyte-free (E-) pastures). The infestation of horn fly load decreased according to an increase in the percentage of endophyte present in the different pastures (0 to 100%). Moreover, two groups of animals with significant differences in the fly-load (high and low fly-load) in the same herd were observed (P < 0.05). Additionally, it was possible to determine a bioinsecticide effect of cattle dung, upon horn fly larvae (80%), from animals fed E+ tall fescue. Conclusions: These results constitute the first report on the potential for exploiting pasture management for controlling 1) horn fly-loads on cattle and 2) the normal development of horn fly larvae. In conclusion, this information provides preliminary understanding of the role of cattle pasture diet management for controlling horn fliesas part of an integrated pest management strategy for this major pest of farmed livestock

Direct oral anticoagulants for the treatment of cerebral venous thrombosis – a protocol of an international phase IV study

IntroductionCurrent guidelines recommend that patients with cerebral venous thrombosis (CVT) should be treated with vitamin K antagonists (VKAs) for 3–12 months. Direct oral anticoagulants (DOACs), however, are increasingly used in clinical practice. An exploratory randomized controlled trial including 120 patients with CVT suggested that the efficacy and safety profile of dabigatran (a DOAC) is similar to VKAs for the treatment of CVT, but large-scale prospective studies from a real-world setting are lacking.MethodsDOAC-CVT is an international, prospective, observational cohort study comparing DOACs to VKAs for the prevention of recurrent venous thrombotic events after acute CVT. Patients are eligible if they are 18 years or older, have a radiologically confirmed CVT, and have started oral anticoagulant treatment (DOAC or VKA) within 30 days of CVT diagnosis. Patients with an absolute contra-indication for DOACs, such as pregnancy or severe renal insufficiency, are excluded from the study. We aim to recruit at least 500 patients within a three-year recruitment period. The primary endpoint is a composite of recurrent venous thrombosis and major bleeding at 6 months of follow-up. We will calculate an adjusted odds ratio for the primary endpoint using propensity score inverse probability treatment weighting.DiscussionDOAC-CVT will provide real-world data on the comparative efficacy and safety of DOACs versus VKAs for the treatment of CVT.Clinical trial registrationClinicalTrials.gov, NCT04660747

Adaptive mesh and finite element analysis of coupled fluid/structure: application to brain deformations

National audienceDans cet article, nous nous intéressons à la modélisation bio-mécanique des tissus mous cérébraux, dans le cadre des opérations de neuro-chirurgie guidée par l'image. La simulation numérique des déformations permet de prendre en compte les déformations subies en per-opératoire par les structures cérébrales, (phénomène du brainshift), et qui affecte notamment le cortex, la tumeur et les ventricules. Le caractère peu prévisible de ces déformations dues à un nombre de facteurs importants (gravité, perte de LCS, entre autres...), rend essentiel de disposer d'une simulation per-opératoire de qualité

Production, permanence and germination of seeds of Araucaria araucana (Mol.) K. Koch in natural forests, used by indigenous communities in southern Chile

Currently, forests of Araucaria araucana in Chile are primarily used for non-timber purposes. From ancient times, their seeds (piñones) have been collected by people and are also consumed by domestic livestock. To evaluate the use of piñones in three localities in the Lonquimay commune, 90 sub-permanent monitoring plots were established to estimate the available amounts of piñones, their permanence and the recruitment of A. araucana regeneration. In localities with more families and livestock per hectare, the amount of seeds remaining in the forest is significantly lower. The same situation occurs when analyzing natural regeneration of araucaria. To ensure the sustainability of these forests, it is necessary to regulate the consumption of piñones by livestock, and its harvest rate.Los bosques de Araucaria araucana en Chile hoy son destinados principalmente a usos no madereros. En los bosques se colecta desde tiempos ancestrales las semillas (piñones), que además son consumidas por el ganado doméstico. Para evaluar el aprovechamiento de los piñones que tiene lugar en tres localidades de la comuna de Lonquimay, se establecieron 90 subparcelas de monitoreo permanente con el fin de estimar los montos de piñones disponibles, la permanencia de éstos y el reclutamiento de regeneración de A. araucana. En las localidades con mayor número de familias y cabezas de ganado por hectárea, la cantidad de semillas que permanece en el bosque es significativamente menor. Esta situación se repite al analizar la regeneración natural de araucaria. Para asegurar la sostenibilidad de estos bosques es necesario regular el consumo de piñones por el ganado y la tasa de recolección

Adaptive mesh and finite element analysis of coupled fluid/structure: application to brain deformations

National audienceDans cet article, nous nous intéressons à la modélisation bio-mécanique des tissus mous cérébraux, dans le cadre des opérations de neuro-chirurgie guidée par l'image. La simulation numérique des déformations permet de prendre en compte les déformations subies en per-opératoire par les structures cérébrales, (phénomène du brainshift), et qui affecte notamment le cortex, la tumeur et les ventricules. Le caractère peu prévisible de ces déformations dues à un nombre de facteurs importants (gravité, perte de LCS, entre autres...), rend essentiel de disposer d'une simulation per-opératoire de qualité

Hemoglobinas Em Siluriformes Da Amazônia Central. Iii Caracterização Imunológica De Alguns Bagres E Cascudos.

Specific antisera to Oxydoras niger (Doradidae: cuiú-cuiú) and Plecostomus plecostomus (Loricariidae: cascudo-pedra) hemoglobin were tested against fish hemoglobin of Doradidae; Auchenipteridae; Pimelodidae; Angeneiosidae; Loricariidae and Callichthyidae. Serological double diffusion tests in agar have shown that O. niger antiserum gives positive reaction against hemoglobin of all the species of "bagres" and "cascudos" tested with only two exceptions P. plecostomus (cascudo-pedra) and P. pardalis (cascudo comum) fraction I hemoglobin which gave negative reactions. On the other hand, the P. plecostomus antiserum gave positive reaction only for the homologous and P. pardalis fraction I antigens.Hemoglobinas de peixes Siluriformes pertencentes às famílias Doradidae; Auchenipteridae; Pimelodidae; Angeneiosidae; Loricariidae e Callichthyidae foram testadas contra anti-soros preparados para hemoglobina de Oxydoras niger (Doradidaecuiú-cuiú) e Plecostomus plecostomes (Loricariidaecascudo pedra). As reações serológicas de dupla difusão em ágar mostraram que o anti-soro para O. niger reagiu com hemoglobinas de todas as espécies de bagres e cascudos testadas, com exceção de P. plecostomus (cascudo pedra) e da fração I da hemoglobina de P. pardalis (cascudo comum). Por outro lado, o anti-soro para P. plecostomus (cascudo pedra) reagiu apenas com o antígeno homólogo; com a fração I de hemoglobina de P. pardalis (cascudo comum) e com hemoglobina humana

Plasma Levels of Diphenylhydantoin and the Control of Adult Epileptic Seizures: A Chilean Experience

:In a prospective study of 117 adult ambulatory patients, 110 of whom were epileptics treated only with oral diphenylhydantoin (DPH), plasma levels of this drug were determined by gas‐liquid chromatography. The average follow‐up time was 6 months (range, 3 to 13 months); satisfactory control of seizures was obtained with plasma levels in the 10.2 to 25.8 μg/ml range, representing 68% of the patients whose seizures had been controlled. The dosage received by this group was from 4.2 to 6 mg/kg, with an average of 5.1. In general, these results agree with those found in European or North American patients, even though some differences or little clarity in the methodology of other trials make comparison difficult. This similarity of results makes one think that genetic or environmental differences do not alter the response to DPH in our patients, but further studies are necessary in that area. This paper can serve as a basis for the extrapolation of data about DPH coming from other latitu

Overexpression of the cholesterol-binding protein MLN64 induces liver damage in the mouse.

AIM: To examine the in vivo phenotype associated with hepatic metastatic lymph node 64 (MLN64) over-expression. METHODS: Recombinant-adenovirus-mediated MLN64 gene transfer was used to overexpress MLN64 in the livers of C57BL/6 mice. We measured the effects of MLN64 overexpression on hepatic cholesterol content, bile flow, biliary lipid secretion and apoptosis markers. For in vitro studies cultured CHO cells with transient MLN64 overexpression were utilized and apoptosis by TUNEL assay was measured. RESULTS: Livers from Ad.MLN64-infected mice exhibited early onset of liver damage and apoptosis. This response correlated with increases in liver cholesterol content and biliary bile acid concentration, and impaired bile flow. We investigated whether liver MLN64 expression could be modulated in a murine model of hepatic injury. We found increased hepatic MLN64 mRNA and protein levels in mice with chenodeoxycholic acid-induced liver damage. In addition, cultured CHO cells with transient MLN64 overexpression showed increased apoptosis. CONCLUSION: In summary, hepatic MLN64 over-expression induced damage and apoptosis in murine livers and altered cholesterol metabolism. Further studies are required to elucidate the relevance of these findings under physiologic and disease conditions

Risk factors for cardiovascular disease in the developing world. A multicentre collaborative study in the International Clinical Epidemiology Network (INCLEN)

Twelve centres in 7 countries in the Developing World (China, Thailand, the Philippines, Indonesia, Chile, Colombia and Brazil) connected with the International Clinical Epidemiology Network (INCLEN) each measured cardiovascular disease (CVD) risk factors in random samples of approx. 200 men aged between 35 and 65 years. Samples of men aimed to be representative of the population from which they were drawn, but the population in each centre was not designed to be representative of the whole country. Cigarette smoking rates varied from 16 to 78% and mean cholesterol levels varied from 3.8 to 6.4 mmol/l. In Bogota, Colombia, 46% of the men had a cholesterol level > 6.5mmol/l and in another 5 communities 19% or more of the population had these levels. A body mass index (BMI) of > 25 was seen in more than 50% of 4 communities and a blood pressure ? 160mmHg systolic and/or 95 mmHg diastolic was found in more than 20% of 6 countries. BMI was strongly correlated with blood cholesterol and blood pressure levels in almost all population groups. It would appear that many communities in the Developing World have high levels of risk factors for CVD and that steps could well start to be taken now to prevent the emergence of CVD epidemics in the future