Experimental evaluation of system modifications to increase R1234ze(E) cooling capacity

The GWP limitations are being progressively introduced in Europe through Regulation EU No 517/201, phasing out R134a in most of its refrigeration and air conditioning applications. Pure hydrofluoroolefins are proposed to substitute this fluid, however generally system modifications are needed to achieve a good performance. In the case of R1234ze(E), the cooling capacity is always much below that of R134a in drop-in or light retrofit substitutions. This work performs an experimental comparison using R1234ze(E) and R134a under different refrigeration operating conditions. R1234ze(E) is tested considering the use or not of an internal heat exchanger, and R134a at the same or lower compressor rotation speed. Results show that the use of R1234ze(E) with an open-type compressor 43% larger and an internal heat exchanger of 25% effectiveness, leads to a cooling capacity augmentation, enough to reach R134a cooling capacity in the different conditions tested. For R450A, it is sufficient only with the IHX activation

The Cross-Cultural Adaptation of International Medical Graduates to General Practice in New Zealand

This study demonstrates that occupational success is an important factor in the adaptation of highly skilled migrants to host societies, as seen through the experiences of the international medical graduates (IMGs) who came to New Zealand and became general practitioners (GPs). New Zealand is reliant on IMGs to support and deliver quality health care to its population: IMGs constitute over 40% of the current medical workforce. The central contributions of this thesis are to three distinct discourses on the experiences of migrants. The first contribution is an investigation and critical analysis of the experiences of IMGs who came to practise medicine in New Zealand. During the course of analysing the primary data, and relating it to existing literature, it was observed there was a lack of a model that captured the essence of the specific acculturation of highly skilled migrants such as IMGs. Therefore, the second contribution is the development of a concise integrated framework - the Integrated Framework for Acculturative Research (IFAR), for the study of highly skilled migrants’ acculturation to new environments. The experiences of the IMGs who came to New Zealand have been used to develop and discuss the application of the IFAR to cross-cultural adaptation research. There is an historical component to these narratives as the IMGs in this research spanned nearly five decades of acculturation into New Zealand society. The third contribution is in the domain of qualitative research, where email interviews (e-interviews) have been used to gather data within the context of ethnography. While there has been significant literature, theories and models developed about cross-cultural and intercultural adaptation of migrants into host nations, there are gaps in the understanding of the experiences of highly skilled migrants, who are different from other types of migrants, given their predispositions and higher levels of human capital such as education and work experience. There is an emerging literature on this subject, to which this study adds. The IMGs in this study used their human capital to become medical practitioners in New Zealand, achieving their main motivation for migrating in the first place. The reasons the IMGs stated for migration are consistent with existing literature on ‘push’ and ‘pull’ factors; however for all of them, the primary reason was to pursue their medical careers in New Zealand. After arrival, most of them had to do additional training before they were allowed to practise independently. The medical training ranged from those required to achieve the registration of the Medical Council of New Zealand (MCNZ), to those needed to achieve the Fellowship of the Royal New Zealand College of General Practitioners (RNZCGP). The participants noted several challenges during their training period, including a lack of clear information on what was required; having to prove their ability despite many years of experience as medical practitioners; dealing with poor teachers for some; having to travel long distances to attend training seminars; and for a few, dealing with financial constraints. However, they all overcame such challenges and became successful independent GPs. Their age, pre-migration human capital, and post-migration motivation were essential in initiating their desired occupations in New Zealand. These three success factors are supported by emerging literature on highly skilled migrants. The early participants initially worked in hospital settings before choosing general practice. Some left because they experienced issues in the hospital environment such as tensions with local colleagues, and the need to work long unfriendly hours. All participants noted that the reasons for choosing general practice included their desire to work more closely with communities and to experience a greater variety of medicine. Additionally, many reported that the flexibility of working in general practice gave them a better work/life balance that allowed them to do other things within the community and outside of their general practice. Female participants noted that general practice was more conducive when raising a family, compared to hospital-based specialties. These are the strengths of general practice that are well documented in literature. While the participants did not note any major ongoing challenges, some reported being frustrated with the poor links between primary and secondary health care that impacted on the timely care of their patients. With an increase in chronic conditions and mental health issues, coupled with an ageing population, many participants reported that they needed more time and frequent consultations to treat certain patients. Given New Zealand’s co-payment system, participants reported having to consider the appropriate levels of care for patients with chronic conditions so as not to financially overburden them. For participants working in rural and economically deprived areas, there were other social factors that affected their medical practice, such as the high levels of family violence, sexual health issues, teenage pregnancies and substance abuse. These issues are supported by current literature regarding health and society in New Zealand. Despite the challenges they faced, all the IMGs planned on continuing to work in general practice in New Zealand for the foreseeable future. Migrants’ pledge of continuing in their chosen occupations in host nations can be a very good indicator of acculturation and integration. The MCNZ reported that nearly two-thirds of all IMGs left New Zealand two years post-registration. However, retention rates improved significantly once IMGs obtained their vocational registration. Occupational continuity sheds light on immigrants’ level of acculturation because it establishes that they are comfortable living among the hosts, and working in their chosen professions. This study demonstrates that occupational success is a key prerequisite to continuity and long-term integration into host societies. As highly skilled migrants, they could have gone to almost any country but they chose New Zealand. They remain here, having forged their medical careers and a lifestyle of their choosing. They now consider New Zealand their home, at least until they enter a different stage of their lives

Variable speed liquid chiller drop-in modeling for predicting energy performance of R1234yf as low-GWP refrigerant

This paper presents a model for a variable-speed liquid chiller integrating a compressor model based on Buckingham π-theorem to accurately predict the system performance when R134a is replaced with R1234yf, using a wide range of data obtained from an experimental setup. Relevant variables such as temperature, pressure, mass and volumetric flow rates, compressor power consumption and rotation speed were measured at several positions along the refrigeration and secondary circuits and were used to validate the developed model. Model results show that cooling capacity and power consumption predicted values are in good agreement with experimental data, within ±5%, being slightly higher for the deviation obtained for R134a than for R1234yf. Moreover, model results indicate that R1234yf has a reduction of coefficient of performance (COP) compared with R134a (between 2 and 11.3%), and that R1234yf COP reduction is diminished at intermediate volumetric flow rate and higher inlet temperature for the evaporator secondary fluid, respectively. On the other hand, an environmental analysis based on TEWI (total equivalent warming impact) method showed that direct emissions are almost negligible for R1234yf. However, there are no environmental benefits in terms of indirect greenhouse gas emissions using R1234yf without system modifications (as for instance the addition of internal heat exchanger or R1234yf new design components), which are required to reduce the liquid chiller climate change contribution using it as low GWP alternative in comparison with the typically used R134a refrigerant

Comparative evaluation of R1234yf, R1234ze(E) and R450A as alternatives to R134a in a variable speed reciprocating compressor

A comparative energetic evaluation of R1234yf, R1234ze(E) and R450A as alternatives to R134a in a variable speed compressor is carried out. A compressor model based on dimensionless numbers was obtained using the Buckingham p -theorem, which was validated with experimental data; showing that the prediction error of the model is lower than ± 10% and ± 2 K for temperature. The experimental data were obtained by testing R134a, R1234yf, R1234ze(E) and R450A for a wide range of operating condi- tions. Results obtained with the validated model, show that the dimensionless approach provides a similar estimation of energy parameters compared with the experimental results, such as power con- sumption, refrigerant mass fl ow rate, cooling capacity, COP, discharge temperature and compressor ef- fi ciencies for each refrigerant tested using the dimensionless approach proposed. The comparative evaluation of the compressor predictions shows a reduction in the cooling capacity obtained with R1234yf, R450A and R1234ze(E), in comparison with R134a. Also, COP values for R1234yf, R450A, and R1234ze(E) are lower than those obtained from R134a. Finally, results shows that the dimensionless correlation compressor model can be used to predict the performance of other reciprocating compres- sors, at similar operating conditions for a wide range of compressor rotation speed, with a reasonable accuracy.The authors thankfully acknowledge to the "Consejo Nacional deCiencia y Tecnología (CONACYT)” for their support to this study, and to the “Ministerio de Educación, Cultura y Deporte” (Grant number FPU12/02841) for sponsoring this work through “Becas y Contratosde Formación de Profesorado Universitario del Programa Nacional de Formación de Recursos Humanos de Investigación del ejercicio 2012”

Efecto del propionato de calcio en la fermentación in vitro de dietas a base de sorgo

The objective of the present study was to evaluate the effect of calcium propionate (CaPr) on in vitro ruminal fermentation using a factorial arrangement 2 x 2 evaluating CaPr (0 vs. 1%) and grain level (55 vs. 65%). There was a CaPr x Grain interaction in the volume of gas produced (V; p = 0.04). Addition of CaPr prolonged Lag time (1.4 vs. 1.04 h; P<0.01), and increasing the grain level also prolonged Lag time (1.56 vs. 0.89 h; p < 0.03) and gas production rate (0.046 vs. 0.041 h-1; P<0.04). However, there were no differences in CH4, CO2, acetate, propionate and butyrate concentrations. Therefore, the addition of calcium propionate in a diet with 55 or 66% of grain increased Lag phase but it is not affected fermentation pattern or methane losses.El objetivo de este estudio fue evaluar in vitro el efecto de la adición de propionato de Ca (PrCa). El diseño experimental fue completamente al azar con un arreglo factorial 2x2; PrCa (0 o 1%) y grano (55 o 65%). Se encontró diferencias (p>0,05) entre tratamientos para volumen de gas, pero la tasa de producción de gas no fue diferente (p<0,05), se observó un efecto por parte del grano (p<0,04). La adición de PrCa prolongó el tiempo Lag (1,4 vs. 1.04 h; P<0,01) y aumentando el nivel de grano también prolongó la fase Lag (1,56 vs. 0,89 h; P<0,03) y la tasa de producción de gas (0,046 vs. 0,041 h-1; P <0,04). Sin embargo, no hubo diferencias en la concentración de CH4 y CO2, ni de propionato, acetato y butirato. La adición de propionato de calcio a una dieta con 55 o 65% de grano prolonga la fase Lag pero no afecta el patrón de fermentación o las pérdidas de metano.Fil: Miranda, Luis Alberto. Universidad Autónoma Chapingo (México)Fil: Lee-Rangel, Héctor Aarón. Universidad Autónoma de San Luis Potosí. Facultad de AgronomíaFil: Mendoza-Martínez, Germán David.Fil: Crosby-Galván, María Magdalena. Colegio de Postgraduados. Campus Montecillo (México)Fil: Relling, Alejandro Enrique. Universidad Nacional de la Plata. Facultad de Ciencias VeterinariasFil: Pinos-Rodríguez, Juan Manuel. Universidad Autónoma de San Luis Potosí. Facultad de AgronomíaFil: Rojo Rubio, Rolando . Universidad Autónoma del Estado de MéxicoFil: González Hernandez, Milagros. Universidad Autónoma de San Luis Potosí. Facultad de Agronomí

Efecto del propionato de calcio en la fermentación in vitro de dietas a base de sorgo

El objetivo de este estudio fue evaluar in vitro el efecto de la adición de propionato de Ca (PrCa). El diseño experimental fue completamente al azar con un arreglo factorial 2x2; PrCa (0 o 1%) y grano (55 o 65%). Se encontró diferencias (p0,05) entre tratamientos para volumen de gas, pero la tasa de producción de gas no fue diferente (p0,05), se observó un efecto por parte del grano (p0,04). La adición de PrCa prolongó el tiempo Lag (1,4 vs. 1.04 h; P0,01) y aumentando el nivel de grano también prolongó la fase Lag (1,56 vs. 0,89 h; P0,03) y la tasa de producción de gas (0,046 vs. 0,041 h-1; P 0,04). Sin embargo, no hubo diferencias en la concentración de CH4 y CO2, ni de propionato, acetato y butirato. La adición de propionato de calcio a una dieta con 55 o 65% de grano prolonga la fase Lag pero no afecta el patrón de fermentación o las pérdidas de metano.The objective of the present study was to evaluate the effect of calcium propionate (CaPr) on in vitro ruminal fermentation using a factorial arrangement 2 x 2 evaluating CaPr (0 vs. 1%) and grain level (55 vs. 65%). There was a CaPr x Grain interaction in the volume of gas produced (V; p = 0.04). Addition of CaPr prolonged Lag time (1.4 vs. 1.04 h; P<0.01), and increasing the grain level also prolonged Lag time (1.56 vs. 0.89 h; p < 0.03) and gas production rate (0.046 vs. 0.041 h-1; P<0.04). However, there were no differences in CH4, CO2, acetate, propionate and butyrate concentrations. Therefore, the addition of calcium propionate in a diet with 55 or 66% of grain increased Lag phase but it is not affected fermentation pattern or methane losses.Instituto de Genética Veterinari

Evaluation of R448A and R450A as Low-GWP alternatives for R404A and R134a using a micro-fin tubes evaporator model

[EN] When retrofitting new refrigerants in an existing vapour compression system, their adaptation to the heat exchangers is a major concern. R450A and R448A are commercial non-flammable mixtures with low GWP developed to replace the HFCs R134a and R404A, fluids with high GWP values. In this work the evaporator performance is evaluated through a shell-and-microfin tube evaporator model using R450A, R448A, R134a and R404A. The accuracy of the model is first studied considering different recently developed micro-fin tube correlations for flow boiling phenomena. The model is validated using experimental data from tests carried out in a fully monitored vapour compression plant at different refrigeration operating conditions. The main predicted operational parameters such as evaporating pressure, UArp, and cooling capacity, when compared with experimental data, fit within 10% using the Akhavan-Behabadi et al. correlation for flow boiling. Results show that R450A and R404A are the refrigerants in which the model fits better, even though R448A and R134a predictions are also accurate. (C) 2015 Elsevier Ltd. All rights reserved.The authors thankfully acknowledge "Ministerio de Educacion, Cultura y Deporte" (Grant number FPU12/02841) for supporting this work through "Becas y Contratos de Formacion de Profesorado Universitario del Programa Nacional de Formacion de Recursos Humanos de Investigacion del ejercicio 2012". Finally the linguistic support of Irene I. Elias-Miranda is appreciated.Mendoza Miranda, JM.; Mota-Babiloni, A.; Navarro Esbri, J. (2016). Evaluation of R448A and R450A as Low-GWP alternatives for R404A and R134a using a micro-fin tubes evaporator model. Applied Thermal Engineering. 98:330-339. https://doi.org/10.1016/j.applthermaleng.2015.12.064S3303399

Antitumor activity of colloidal silver on MCF-7 human breast cancer cells

<p>Abstract</p> <p>Background</p> <p>Colloidal silver has been used as an antimicrobial and disinfectant agent. However, there is scarce information on its antitumor potential. The aim of this study was to determine if colloidal silver had cytotoxic effects on MCF-7 breast cancer cells and its mechanism of cell death.</p> <p>Methods</p> <p>MCF-7 breast cancer cells were treated with colloidal silver (ranged from 1.75 to 17.5 ng/mL) for 5 h at 37°C and 5% CO₂atmosphere. Cell Viability was evaluated by trypan blue exclusion method and the mechanism of cell death through detection of mono-oligonucleosomes using an ELISA kit and TUNEL assay. The production of NO, LDH, and Gpx, SOD, CAT, and Total antioxidant activities were evaluated by colorimetric assays.</p> <p>Results</p> <p>Colloidal silver had dose-dependent cytotoxic effect in MCF-7 breast cancer cells through induction of apoptosis, shown an LD₅₀(3.5 ng/mL) and LD₁₀₀(14 ng/mL) (*P < 0.05), significantly decreased LDH (*P < 0.05) and significantly increased SOD (*P < 0.05) activities. However, the NO production, and Gpx, CAT, and Total antioxidant activities were not affected in MCF-7 breast cancer cells. PBMC were not altered by colloidal silver.</p> <p>Conclusions</p> <p>The present results showed that colloidal silver might be a potential alternative agent for human breast cancer therapy.</p

PERSPECTIVA PSICOSOCIAL DE LOS DERECHOS HUMANOS

Hoy en día es imprescindible abordar el problema de los derechos desde una perspectiva holística que integre la posición que el individuo ocupa en la sociedad y el impacto de los hechos sociales sobre su persona. Esta perspectiva va por lo tanto más allá del enfoque clásico de las violaciones a los derechos civiles y políticos de los ciudadanos sino, también incluye sus derechos económicos, sociales y culturales. Cualquier enfoque de tipo holístico debe entender al ser humano en su ambiente, social, cultural, natural y en función a todas las estructuras existentes, por más sutiles que sean o invisibles que parezcan. Precisamente este libro permite apreciar la dimensión amplia y compleja del ser en sociedad y las interacciones que de ambas partes se generan y las ramificaciones que producen. No es un ejercicio fácil y los editores de este volumen han logrado un salto cuántico al poder congregar en un solo espacio miradas que en otras circunstancias podrían haber sido opuestas y hasta contrarias a nuestra comprensión de problemas que, en efecto, tienen raíces comunes. El libro está dividido en 5 secciones, El espíritu de los tiempos actuales y los Derechos Humanos, Construcción ciudadana y ejercicio de los Derechos Humanos, Violaciones a Derechos Humanos, victimizaciones y su atención, Ejercicio de los Derechos Humanos y situaciones disruptivas y Defensa y defensores de Derechos Humanos.Manuel Gutiérrez Romero Jessica Ruiz Magañ

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London