Predictive Methodology for Quality Assessment in Injection Molding Comparing Linear Regression and Neural Networks.

The use of recycled polypropylene in industry to reduce environmental impact is increasing. Design for manufacturing and process simulation is a key stage in the development of plastic parts. Traditionally, a trial-and-error methodology is followed to eliminate uncertainties regarding geometry and process. A new proposal is presented, combining simulation with the design of experiments and creating prediction models for seven different process and part quality output features. These models are used to optimize the design without developing additional time-consuming simulations. The study aims to compare the precision and correlation of these models. The methods used are linear regression and artificial neural network (ANN) fitting. A wide range of eight injection parameters and geometry variations are used as inputs. The predictability of nonlinear behavior and compensatory effects due to the complex relationships between this wide set of parameter combinations is analyzed further in the state of the art. Results show that only Back Propagation Neural Networks (BPNN) are suitable for correlating all quality features in a single formula. The use of prediction models accelerates the optimization of part design, applying multiple criteria to support decision-making. The methodology is applied to the design of a plastic support for induction hobs. Furthermore, this methodology has demonstrated that a weight reduction of 27% is feasible. However, it is necessary to combine process parameters that differ from the standard ones with a non-uniform thickness distribution so that the remaining injection parameters, material properties, and dimensions fall within tolerances.

Tribological Performance of Nylon Composites with Nanoadditives for Self-Lubrication Purposes.

A systematic study comparing the wear behaviour of composites with nylon matrix (PA66, PA46, PA12) and different nanoadditives and reinforcing additives (graphite, graphene, MoS2 and ZrO2) has been carried out in order to achieve a proper self-lubricant material for bearing cages. The wear characterisation was done using pin-on-disc tests, SEM and EDX analysis. The results show that better outcomes are obtained for composites based on PA12. The addition of ZrO2 offers negative values of wear due to the metallic particle transference from the counterface to the polymeric pin.

Correction: Elduque, A., et al. Electricity Consumption Estimation of the Polymer Material Injection-Molding Manufacturing Process: Empirical Model and Application.

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Dimensional Stability and Process Capability of an Industrial Component Injected with Recycled Polypropylene.

The usage of recycled polymers for industrial purposes arises as one of the most promising methods of reducing environmental impact and costs associated with scrapping parts. This paper presents a systematic study of the dimensional stability of a raw and 100% recycled polypropylene subjected to realistic environmental conditions occurring along its working life. The component studied is an internal part of an induction hob assembly. Industrial samples manufactured with both materials, in the same mold, and in the same injection machine, are subjected to ejection conditions, storage conditions (50 °C), and extreme performance conditions (80 °C). Induced dimensional changes are registered and analyzed using a coordinate measuring machine, and a tactile sensing probe. To verify the process capability of the samples manufacturing, Cp and Cpk values are calculated to evaluate the suitability of the recycled material as an alternative. Results conclude that, although the use of recycled material implies slight differences in terms of dimensional stability due to the changes induced in the polymer structure, these differences are not significant enough to affect the injection process capability. Therefore, recycling arises as one effective method to reduce both overruns associated with the consumption of raw polypropylene material and its environmental impact.

Electricity Consumption Estimation of the Polymer Material Injection-Molding Manufacturing Process: Empirical Model and Application.

Polymer injection-molding is one of the most used manufacturing processes for the production of plastic products. Its electricity consumption highly influences its cost as well as its environmental impact. Reducing these factors is one of the challenges that material science and production engineering face today. However, there is currently a lack of data regarding electricity consumption values for injection-molding, which leads to significant errors due to the inherent high variability of injection-molding and its configurations. In this paper, an empirical model is proposed to better estimate the electricity consumption and the environmental impact of the injection-molding process. This empirical model was created after measuring the electricity consumption of a wide range of parts. It provides a method to estimate both electricity consumption and environmental impact, taking into account characteristics of both the molded parts and the molding machine. A case study of an induction cooktop housing is presented, showing adequate accuracy of the empirical model and the importance of proper machine selection to reduce cost, electricity consumption, and environmental impact.

Discordances Between Serology and Culture for Strongyloides in an Ethiopian Adopted Child With Multiple Parasitic Infections: A Case Report.

RATIONALE: infectious diseases screening of international adoptees is complex because of the concurrence of different pathogens in a child at same time. We describe an international adopted child born at Ethiopia infected by 5 different pathogens (Hymenolepis nana, Giardia intestinalis, Entamoeba histolytica, Strongyloides stercoralis, and Trichuris trichiura), 2 of them S. stercoralis and E. histolytica with a capacity to develop severe clinical complications if not detected promptly with appropriate diagnosis tests.Concerns of the patient: according to the screening protocol a stool sample is always processed for culture addressed to find out protozoan and helminthic pathogens but not specifically for S. stercoralis. Only, when eosinophilia is detected 3 serial stool samples are collected to rule out intestinal parasitic infection including S. stercoralis. INTERVENTIONS: in our case, S. stercoralis would not have been detected if we had followed the protocol because eosinophilia was absent and its specific serology was negative. Fortunately, the initial inclusion of the feces charcoal culture for S. stercoralis allowed us to detect this infection. OUTCOMES: discordances between direct methods such as culture and indirect as serology or antigen test forces us to be very cautious before ruling out S. stercoralis or E. histolytica infection, respectively. Also, if a child from tropical areas has persistent symptoms (such as diarrhea or fever) that have not been treated we have to rule out other infections that have not been detected yet.Main lessons: The introduction of different sequencing tests and the insistence to find out pathogens such as S. stercoralis or E. histolytica was determinant to be able to cure this symptomatic child and to prevent potential severe clinical forms in case of immunosuppression.

Controlling congenital and paediatric chagas disease through a community health approach with active surveillance and promotion of paediatric awareness.

BACKGROUND: Chagas disease (CD) is endemic in countries of continental Latin America. Congenital transmission is a major concern worldwide. In 2010, the Public Health Agency of Catalonia (ASPCAT) launched a screening protocol for Trypanosoma cruzi infection in pregnant women and their newborns. In 2012, ASPCAT detected appropriate follow-up of pregnant women but incomplete information about their offspring. METHODS: The PROSICS community health team carried out active surveillance and community health action in target populations. These activities included active case searches, group awareness workshops and visualization campaigns as well as investigation of all lost children born from pregnant women with CD and their families. RESULTS: Overall, 42/179 (23.5%) cases were included in the study: 35/42 (83.3%) children were born in Hospitalet de Llobregat (Catalonia, Spain); 4/42 (16.7%) were born in Latin America; two were miscarried and one was stillborn. The mean age of pregnant women was 31.3 years (SD 5.52; range: 21-44): 90.5% were Bolivian, of whom 74% were diagnosed with CD during pregnancy. Of the 35 newborns, 31 were recovered by community health action; 12/31 were correctly controlled at Hospitalet de Llobregat and 19/31 were controlled at a primary health centre. Of these 19 (73.7%) cases, 14 were not tested for CD by family paediatricians and were recovered by the PROSICS community health team. Finally, two (6.9%) of the 29 newborns tested with serology were positive. CONCLUSIONS: It is essential to implement active surveillance, education and information activities at paediatric primary care and community levels to avoid the loss of CD-infected mothers and their newborns. Training sessions addressed to paediatricians and other involved health professionals would consolidate surveillance and care reference circuits, improving the control of congenital CD.

Enfermedad de Chagas importada en una gran ciudad europea: la experiencia en un centro especializado de Barcelona (2004-2006) / No disponible

Fundamento: El importante aumento de la inmigración en Barcelona los últimos años y concretamente la presencia de inmigrantes procedentes de zonas endémicas de enfermedad de Chagas condiciona que ésta sea una enfermedad emergente en nuestro medio. Este estudio describe las características epidemiológicas de los pacientes infectados por Trypanosoma cruzi atendidos en la Unitat de Medicina Tropical i Salud Internacional Drassanes (UMTSID), y analiza las derivaciones y los motivos de consulta por los cuales fueron atendidos. Métodos: Estudio descriptivo transversal de todos los pacientes procedentes de América Latina, diagnosticados de enfermedad de Chagas, y atendidos en la UMTSID desde julio de 2004 a enero de 2006. Se recogieron las siguientes variables: edad, sexo, país de nacimiento, meses de residencia en España, antecedentes de transfusión sanguínea, permanencia en área rural, viajes a otros países endémicos, motivos de consulta y derivación. Resultados: De los 216 pacientes atendidos en la UMTSID procedentes de países endémicos se diagnosticó enfermedad de Chagas en 46 de ellos. De estos el 83% eran mujeres y el 91% procedía de Bolivia. Los motivos de consulta más frecuentes fueron: diagnóstico previo un 37%, eosinofilia un 17% y cribado general un 15%. El porcentaje de pacientes que acudió por cuenta propia fue el mismo que los derivados por el médico de familia un 41%.Conclusiones: Estos resultados reflejan el trabajo conjunto de la UMTSID con los equipos de atención primaria(EAP) respecto a algunos protocolos, como por ejemplo el de eosinofilia, a pesar de que no se relacione con la enfermedad, pero también demuestran falta de criterios claros por parte de los profesionales médicos para iniciar su estudio. Además se plantean interrogantes respecto a los (..) (AU)

Background: The significant presence of immigrant people from endemic areas of Chagas disease has becomea reality in the medical centres in our country. The present study describes the epidemiological characteristics of patients diagnosed with Trypanosoma cruzi infection attended in the Barcelona Tropical and International Health Unit Drassanes, and analyzes the referrals and consultation reasons. Methods: Descriptive study of all patients from Latin America, Chagas’ disease diagnosed and treated in the UMTSID from July 2004 to January 2006. Variables analyzed were: age, genre, country and department of birth, time after arrival to Spain, past blood transfusions, staying in rural area, travelling to other endemic countries, referral and consultation reason. Results: Of 216 persons coming from the endemic countries, forty-six were diagnosed and studied, most of them were women (83%) and coming from Bolivia (91%). The consultation reasons were previous diagnosis of Chagas disease (37%), eosinophilia (17%), general screening (15%), cardiac (9%) or digestive (9%) symptoms andbeing an infected mother’s child (4%). The same number of patients, 41%, went by themselves and referred by their general practitioner. They also came referred by the paediatrician (7%), gynaecologist (2%), cardiologist (2%)or by family advice (7%).Conclusions: The analysis of the results shows the coordination of the Unit with the primary care services through some protocols such as eosinophilia, despite it is not related to the Chagas disease, but also the lack of established criteria to start the study of the disease. The presence of Chagas disease outside endemic countries demands a greater formation, an approach from different levels (including the social ones) and an extensive epidemiological study (AU)

Communicable diseases in the immigrant population attended to in a tropical medicine unit: epidemiological aspects and public health issues.

For geographical and historical reasons, Spain is receiving an increasing number of immigrants. The aim of this study was to evaluate some epidemiological aspects and the main public health issues of communicable diseases in Barcelona's immigrant population. From 2001 to 2004, a population of immigrants from tropical, subtropical regions and Eastern Europe was attended to in our centre. Each patient was offered a complete screening for tropical and common diseases. The prevalence and demographical characteristics of eight diseases with a potential risk of transmission in our setting were studied: latent and active tuberculosis, syphilis, human immunodeficiency virus (HIV), hepatitis B virus (HBV) and hepatitis C virus (HCV), Chagas disease, Giardia intestinalis and Entamoeba histolytica/Entamoeba dispar. In all, 2464 immigrants mainly from sub-Saharan Africa were seen. Among the patients who underwent the screening, 46.5% had a positive tuberculin skin test (>or=10 mm), incidence of active tuberculosis was 324.7/100,000 immigrants in the period of the study, 6.4% had a positive syphilis serology, 7.7% had a positive HBsAg, 3.1% had a positive serology for HCV and 2.8% were HIV positive, 41 patients from Latin America with risk factors for American Trypanosomiasis were screened for Chagas disease by immunofluorescence assay and 34% had a positive result; 5.4% of stools parasitological tests were positive for G. intestinalis; 4.2% for E. histolytica/E. dispar. Communicable diseases in immigrant population could lead to emerging and re-emerging infections in the European Union with important issues for public health. European countries may have to establish guidelines for screening of infectious diseases in immigrants from low-income countries.

Enfermedad de Chagas crónica: Presentación de tres casos con afectación digestiva / No disponible

La enfermedad de Chagas, endémica en América Latina, es hoy una realidad en nuestro medio. La forma digestiva crónica en América está descrita en los países al sur del ecuador y afecta, en especial, al esófago y/o al colon. Las manifestaciones clínicas más frecuentes son disfagia y estreñimiento. Se describen tres casos importados de enfermedad de Chagas crónica con afectación digestiva (AU)

Chagas disease, endemic in Latin America, is now-a-days a reality in Western Countries as imported disease. The chronic digestive form has been described in countries at south of equator in America and affects especially esophagus and colon. The most frequent clinical symptoms are dysphagia and constipation. We describe 3 imported cases of chronic Chagas diseases with digestive involvement (AU)