207 research outputs found

    Optimization of the investment casting process

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    Rapid prototyping is an important technique for manufacturing. This work refers to the manufacture of hollow patterns made of polymeric materials by rapid prototyping technologies for its use in the preparation of ceramic molds in the investment casting process. This work is focused on the development of a process for manufacturing patterns different from those that currently exist due to its hollow interior design, allowing its direct use in the fabrication of ceramic molds; avoiding cracking and fracture during the investment casting process, which is an important process for the foundry industry

    Optimiranje postupka kalupljenja u ljevačkom procesu

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    Rapid prototyping is an important technique for manufacturing. This work refers to the manufacture of hollow patterns made of polymeric materials by rapid prototyping technologies for its use in the preparation of ceramic molds in the investment casting process. This work is focused on the development of a process for manufacturing patterns different from those that currently exist due to its hollow interior design, allowing its direct use in the fabrication of ceramic molds; avoiding cracking and fracture during the investment casting process, which is an important process for the foundry industry.Brzo razvijanje prototipa važna je proizvodna tehnika. Ovaj se rad odnosi na proizvodnju šupljih kalupa izrađenih od polimerskih materijala pomoću tehnologija brzog razvijanja prototipa za uporabu u izradi keramičkih modela u postupku kalupljenja ljevačkog procesa. Ovaj rad je usmjeren na razvijanje postupka za proizvodnju kalupa drukčijih od onih kakvi trenutno postoje i to zbog svoje šuplje unutarnje izvedbe čime se omogućava izravna uporaba u izradi keramičkih modela te se izbje gava pucanje i lom tijekom postupka kalupljenja ljevačkog procesa koji predstavlja važan postupak u ljevaoničkoj industriji

    Development of efficient recirculation system for Tilapia (Oreochromis niloticus) culture using low cost materials

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    In the current experiment, a recirculation system was built using low cost materials that are available locally and its performance was tested. The performance evaluation procedure was carried out in an aquaculture system in greenhouse with sex-reversed male Nile tilapia (Oreochromis niloticus) production in Querétaro State, Mexico. The recirculation system had four sections (sediment collector, gravel and sand filters, biofilter and clarification) in order to eliminate the organic matter produced by the fish excretion material and uneaten food, as well as, the nitrogenous compounds undesirable in the water tanks, such as, total ammonia nitrogen (TAN). The monitored variables include: temperature, dissolved oxygen, pH, visibility, TAN, nitrites and nitrates. The obtained data were compared with previous studies to evaluate the achieved state of the system. This research clearly demonstrated that it is feasible to use the proposed configuration in aquaculture systems in areas where water source is limited. Consequently, the obtained results represent an environmental standpoint for the conservation of water use in the aquaculture industry and also constitute an important contribution to the aquaculture and farmers who receive minimal economic support.Key words: Water recirculation, aquaculture, sustainability, low cost, water use efficiency

    Productive Performance of Growing Cattle Grazing a Silvopastoral System with \u3cem\u3eLeucaena leucocephala\u3c/em\u3e

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    In tropical regions, the feeding of cattle is usually based on the grazing of medium to low quality grasses. Low fertility of soils, changing climatic conditions and the poor management of pastures, have further reduced the quality and forage yield of pastures. The low availability and quality of grasses gives modest weight gains for grazing cattle and this in-turn causes low economical efficiency of cattle production systems (Campos et al. 2011). Silvopastoral systems represent a sustainable option for meat and milk production in the tropics. The association of grasses with legumes such as Leucaena leucocephala (leucaena) supply forage with high concentration of crude protein (Barros et al. 2012). There are reports in the scientific literature which show that intake of leucaena can result in good rates of growth in cattle (e.g. Shelton and Dalzell 2007); however the presence of the free amino acid mimosine and its metabolites (3,4-DHP and 2,3-DHP) in leucaena when the anaerobic bacteria Synergistes jonesii (Allison et al. 1992) is absent from the rumen, may induce subclinical toxicity in grazing ruminants (Graham 2007; Dalzell et al. 2012; Phaikaew et al. 2012). There are no reports in Mexico regarding the rate of growth of cattle grazing silvopastoral systems with leucaena. The aim of the present work was to evaluate the rate of growth of cattle grazing an association of Panicum maximum and leucaena compared to that of cattle fed a high grain ration (feedlot)

    Glucemia como factor de riesgo en pacientes internados en la Unidad de Cuidados Intensivos de Adultos del Hospital de Clínicas

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    Objetivo: Determinar la relación entre glucemias al ingreso y la evolución de los pacientesadmitidos a la Unidad de Cuidados Intensivos de Adultos (UCIA). Material y Métodos: estudio de cohorte retrospectivo de pacientes en la UCIA, tomando un muestreo, según distintos estratos de glucemia en mg/dL (Gl65; G2 66 a 79; G3 80 a 199 y G4200). Resultados: 413 pacientes, con edad media 48.89 años ±19; glucemia media al ingreso de 168.8 mg/dL (±93). 11.9% eran diabéticos conocidos. Al ingreso el Apache II fue 16±9, con una mortalidad global de 39.7%. Se constataron infecciones intrahospitalarias en 22.8%. La mortalidad en G4 fue de 49,5% vs. 35.4% en G3 (RR 1,41 p=0.008); en cirugías programadas fue en G4 de 30.6% y 14.7% en G3 (RR 2,07 p=0,04), con una tendencia significativa en las cirugías cardiacas (RR 2,33 p=0,11) y neurológicas (RR 3,33 p=0,26); la mortalidad en las cirugías de urgencia fue en G4 44,4% vs. 44,1% en G3 (RR 1,01 p=0,97). Los cuadros médicos en general presentaron una mortalidad de 76 % en G4 vs. 45% en G3 (RR 1,53 p=0,004). Los cuadros coronarios reportaron una mortalidad en G4 de 42 % vs. 10% en G3 (RR 7,13 p=0,001); en cuanto a hipoglucemia, existió una tendencia a mayor mortalidad general en G1 en comparación a G2 y G3 (35% vs. 63,6%) (RR 1,80 p=0,05) Conclusiones: La mortalidad general, de cirugías programadas y síndromes coronarios agudos fue mayor en forma significativa cuando la glucemia de ingreso fue 200 mg/dL

    Urinary Excretion of Mimosine Metabolites by Hair Sheep Fed Foliage of \u3cem\u3eLeucaena leucocephala\u3c/em\u3e

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    Leucaena leucocephala is an adapted legume widely distributed in the tropical regions of Mexico. The high crude protein content of leucaena leaves renders it appropriate for ruminant feeding under commercial conditions. However, the foliage contains the non-protein amino acid mimosine, which, if consumed in high amounts, may induce toxicity in animals which have not previously consumed the legume or without microorganisms capable of degrading mimosine and its derivatives 2,3-DHP (dihydroxypyridine) and 3,4-DHP (Hammond 1995, Palmer et al. 2010, Dalzell et al. 2012). Barros-Rodríguez et al. (2012) found that dry matter intake and weight gain were reduced when sheep grazed paddocks with 55,000 plants of leucaena per hectare. Early work in Australia led to the isolation of Synergistes jonesii, an anaerobic bacterium able to degrade 3,4-DHP and 2,3-DHP to non-toxic compounds (Allison et al. 1992). In Mexico, the presence of this microorganism in the rumen has not yet been confirmed. Inoculation of non-accustomed animals with rumen liquor of ruminants adapted to the consumption of leucaena can reduce the impact of mimosine and its metabolites on animal health (Ghosh et al. 2009; Palmer et al. 2010). The aim of the present work was to evaluate the effects of transferring rumen liquor of cows adapted to the consumption of L. leucocephala to sheep without experience of consumption, on urinary excretion of 3.4-DHP and 2.3-DHP by means of a colorimetric technique

    Recommendations by the Spanish Society of Hospital Pharmacy, the Spanish Society of Oncology Nursing and the Spanish Society of Medical Oncology for the safe management of antineoplastic medication in cancer patients

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    Aim: To define recommendations that permit safe management of antineoplastic medication, minimise medication errors and improve the safety of cancer patients undergoing treatment. Methods: By reviewing the literature and consulting the websites of various health organisations and agencies, an expert committee from the Spanish Society of Hospital Pharmacy and the Spanish Society of Medical Oncology defined a set of safe practices covering all stages of providing cancer therapy to patients. The Spanish Society of Oncology Nursing revised and endorsed the final list. Results: In total, 68 recommendations arranged in five sections were defined. They include issues concerning the training of health professionals, the technological resources needed, treatment planning, informing the patient and his/her family, the processes of prescribing, preparing, dispensing and administering cancer therapy (orally, parenterally or intrathecally), assessing patient adherence and treatment toxicity. Conclusions: It is essential for healthcare establishments to implement specific measures designed to prevent medication errors, in order to ensure the safety of cancer patients treated with antineoplastic medication

    Effect of having private health insurance on the use of health care services: the case of Spain

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    Background: Several stakeholders have undertaken initiatives to propose solutions towards a more sustainable health system and Spain, as an example of a European country affected by austerity measures, is looking for ways to cut healthcare budgets. Methods: The aim of this paper is to study the effect of private health insurance on health care utilization using the latest micro-data from the European Community Household Panel (ECHP), the Spanish National Health Survey (SNHS) and the European Union Statistics on Income and Living Conditions (EU-SILC). We use matching techniques based on propensity score methods: single match, four matches, bias-adjustment and allowing for heteroskedasticity. Results: The results demonstrate that people with a private health insurance, use the public health system less than individuals without double health insurance coverage. Conclusions: Our conclusions are useful when policy makers design public-private partnership policie

    Recommendations by the Spanish Society of Hospital Pharmacy, the Spanish Society of Oncology Nursing and the Spanish Society of Medical Oncology for the safe management of antineoplastic medication in cancer patients

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    Aim: To define recommendations that permit safe management of antineoplastic medication, minimise medication errors and improve the safety of cancer patients undergoing treatment. Methods: By reviewing the literature and consulting the websites of various health organisations and agencies, an expert committee from the Spanish Society of Hospital Pharmacy and the Spanish Society of Medical Oncology defined a set of safe practices covering all stages of providing cancer therapy to patients. The Spanish Society of Oncology Nursing revised and endorsed the final list. Results: In total, 68 recommendations arranged in five sections were defined. They include issues concerning the training of health professionals, the technological resources needed, treatment planning, informing the patient and his/her family, the processes of prescribing, preparing, dispensing and administering cancer therapy (orally, parenterally or intrathecally), assessing patient adherence and treatment toxicity. Conclusions: It is essential for healthcare establishments to implement specific measures designed to prevent medication errors, in order to ensure the safety of cancer patients treated with antineoplastic medication.This project was supported with unrestricted grants from SEFH and SEOM

    European Surveillance System on Contact Allergies (ESSCA): Characteristics of patients patch tested and diagnosed with irritant contact dermatitis

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    Background Irritant contact dermatitis (ICD) is caused by the acute locally toxic effect of a strong irritant, or the cumulative exposure to various weaker physical and/or chemical irritants. Objectives To describe the characteristics of patients with ICD in the population patch tested in the European Surveillance System on Contact Allergies (ESSCA; ) database. Methods Data collected by the ESSCA in consecutively patch-tested patients from January 2009 to December 2018 were analyzed. Results Of the 68 072 patients, 8702 were diagnosed with ICD (without concomitant allergic contact dermatitis [ACD]). Hand and face were the most reported anatomical sites, and 45.7% of the ICD was occupational ICD (OICD). The highest proportions of OICD were found in metal turners, bakers, pastry cooks, and confectionery makers. Among patients diagnosed with ICD, 45% were found sensitized with no relevance for the current disease. Conclusions The hands were mainly involved in OICD also in the subgroup of patients with contact dermatitis, in whom relevant contact sensitization had been ruled out, emphasizing the need for limiting irritant exposures. However, in difficult-to-treat contact dermatitis, unrecognized contact allergy, or unrecognized clinical relevance of identified allergies owing to incomplete or wrong product ingredient information must always be considered
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