Production of gas diffusion layers with cotton fibers for their use in fuel cells.

The gas diffusion layer (GDL) is one of the most important parts of a proton exchange membrane fuel cell, that plays a key role transporting the current to the collector plates, distributing the reactant gases to the catalyst surface, and evacuating heat and water that is generated during the redox reactions inside the fuel cell. Speaking in terms of production cost, the GDL represents up to 45% of the total cost of the membrane electrode assembling (MEA). However, and despite its crucial role in a fuel cell, until recent years, the GDLs have not been studied with the same intensity as other MEA components, such as the catalyst or the proton exchange membrane. In this work, we present the production process, at laboratory scale, of a low cost GDL, using a non-woven paper-making process. A relevant aspect of this GDL is that up to 40% of their composition is natural cotton, despite which they present good electrical and thermal conductivity, high porosity, good pore morphology, high hydrophobicity as well as gas permeability. Furthermore, when the GDL with its optimum cotton content was tested in a single open cathode fuel cell, a good performance was obtained, which makes this GDL a promising candidate for its use in fuel cells.

Enfermería: ¿Ciencia Normal o Ciencia Revolucionaria? / Nursing: Normal Research or Revolutionary Research? / Enfermagem: Ciência Normal ou Ciência Revolucionária?

Introducción: En Colombia la educación doctoral de enfermería es un progreso relativamente reciente. Tras una década de formación, aspectos como el aporte de nuevo conocimiento, el avance en los diseños - metodologías de investigación, y la cantidad de doctores formados, son subestimadas o inexistentes. Este contexto lleva a indagar al respecto los retos y limitantes de la generación de nuevo conocimiento de enfermería. Objetivos: Discutir el progreso de los doctorados de enfermería en Colombia, como descriptor específico del desarrollo disciplinar y científico del conocimiento enfermero, sustentado a partir de los constructos teóricos planteados en la obra de Thomas Kuhn, y de la trans-disciplinariedad. Metodología: Estudio descriptivo, narrativo basado en una revisión documental de la literatura acerca del perfeccionamiento del conocimiento enfermero llevado a cabo en Colombia. Resultados y Conclusiones: La tasa de titulación de doctores en enfermería no sufre incrementos desde 2011; solamente un 6.4% de los trabajos de tesis doctoral desarrollado, tienen un alcance de tipo concluyente; aunque se evidencia una correlación positiva entre las teorías de enfermería y los problemas de estudio desarrollados por los doctores en enfermería, no es claro el abordaje particular que se hace de los metaparadigmas, y las visiones de enfermería dentro del diseño de cada estudio. Se propone impulsar el trabajo colaborativo (trans-disciplinariedad), así como estimular el desarrollo de programas acordes con las necesidades sentidas de la sociedad colombiana. Se evidencia la no existencia de congruencia entre los postulados de Kuhn y el desarrollo epistemológico de la enfermería actual.

Introduction: In Colombia, the nursing doctoral education is a relatively recent process. After a decade of formation, aspects such as the new knowledge input, the evolution of designs and methodologies of research, and the number of doctoral staff formed are still underestimated. Within this context, it is important to inquire on the challenges and barriers related to generation of new nursing knowledge. Objectives: considering the theoretical constructs derived from Thomas Kuhn's works to discuss the progress of nursing doctorates in Colombia as an indicator of the discipline development. Methodology: This is a descriptive and narrative study from a literature review on the process of nursing knowledge improvement in the Colombian context. Results and Conclusions: The nursing doctorate graduation rate has not increased since 2011; only 6.4% of the doctoral dissertations have a concluding reach; although a positive correlation between the nursing theories and the problems studied by the doctorates was evidenced, the approaches to the meta-paradigms and the nursing visions within each study are not clear. A lack of congruency between Khun's postulates and the epistemological development of present-day nursing in Colombia was also evidenced. Collaborative trans-disciplinary initiatives are encouraged in order to stimulate the development of research programs which address the needs of the Colombian society.

Introdução: Na Colômbia a educação doutoral de enfermagem é um progresso relativamente recente. Depois uma década de formação, aspectos como o aporte de novo conhecimento, o avanço nos desenhos-metodologias de pesquisa, e a quantidade de doutores formados, são subestimadas ou inexistentes. Este contexto leva a procurar respeito aos desafios e limitantes da geração de novo conhecimento de enfermagem. Objetivos: Discutir o progresso dos doutorandos de enfermagem na Colômbia, como descritor específico do desenvolvimento disciplinar e científico do conhecimento enfermeiro, sustentado a partir dos constructos teóricos abordados na obra de Thomas Kuhn, e da transdisciplinaridade. Metodologia: Estudo descritivo, narrativo baseado em uma revisão documentária da literatura acerca do aperfeiçoamento do conhecimento enfermeiro efetuado na Colômbia. Resultados e Conclusões: A taxa de titulação de doutores em enfermagem não sofre incrementos desde 2011; somente um 6.4% dos trabalhos de tese doutoral desenvolvido, têm um alcanço de tipo concluinte; ainda que se evidencia uma correlação positiva entre as teorias de enfermagem e os problemas de estudo desenvolvidos pelos doutores em enfermagem, não é clara a abordagem particular que se faz dos metaparadigmas, e as visões de enfermagem dentro do desenho de cada estudo. Propõe-se impulsionar o trabalho colaborativo (transdisciplinaridade), assim como estimular o desenvolvimento de programas acordes com as necessidades sentidas da sociedade colombiana. Evidencia-se a não existência de congruência entre os postulados de Kuhn e o desenvolvimento epistemológico da enfermagem atual.

Electronic Tool for Distribution and Allocation of Heart on Donation and Transplantation in Mexico.

In Mexico and globally, organs and/or tissues donated from deceased people are insufficient to cover the demand for transplants. In 2014, a rate of 3.6 organ donors per million in habitants was recorded; this is reflected in the transplants performed, including heart transplantation, with a rate of 0.4 per million population. According to the legal framework of Mexico, the National Transplant Center is responsible for coordinating National Subsystem of donation and transplantation, and one of its functions is to integrate and backup information regarding donation and transplantation through the National Transplant Registry System. In July 2015, 45 people were registered in the database of patients waiting for a heart transplant, of which 34.61% were female recipients and 65.39% male. Distribution and allocation processes are a key element to provide a fair distribution for those patients waiting for that organ; thus the creation of an electronic tool is proposed, one that aims to support the decision of the donation and/or transplants coordination committee by providing the necessary elements to make this process more efficient.

Widespread expression of inducible NOS and citrulline in lupus nephritis tissues.

OBJECTIVE: Examine the presence of functional inducible nitric oxide synthase (iNOS) in lupus nephritis lesions. METHODS: Seventeen kidney biopsies from patients with lupus nephritis and an equal number of normal control kidney biopsies were examined for the presence of iNOS and endothelial nitric oxide synthase (eNOS) and citrulline by using immunohistochemical methods. Additionally, iNOS and eNOS mRNAs were examined by reverse transcription -PCR amplification of total renal RNA. RESULTS: All biopsies expressed constitutive eNOS, but in contrast to normal kidney biopsies, 70% of the lupus biopsies also expressed iNOS mRNA and the cognate protein. Eight positive biopsies corresponded to class IV lupus nephritis, which also had a high degree of citrullination. CONCLUSIONS: The data indicate that functional iNOS activity is present in glomeruli as part of the inflammatory process in the kidney; therefore the products of iNOS could play a role in the pathogenesis of lupus nephritis.

Effect of Sr content on the crystal structure and electrical properties of the system La2-xSrxNiO4+delta (0

Materials formulated as La(2-x)Sr(x)NiO(4+delta) (0

Captopril effect on prostaglandin E2, thromboxane B2 and proteinuria in lupus nephritis patients.

OBJECTIVE: High urinary Prostaglandin E2 (PGE2) and thromboxane B2 (TxB2) levels have been reported in lupus nephritis (LN). Captopril diminishes proteinuria and improves glomerular filtration rate (GFR), and may have effect on immune function. We evaluate captopril effect on urinary PGE2, and TxB2. METHODS: Eighteen LN patients were randomly assigned to two groups. Group 1 received only prednisone plus cyclophosphamide. Group 2 received also captopril. Serum creatinine, GFR, RPF, urinary proteins, PGE2 and TxB2, were assessed. RESULTS: There were no differences between the initial and final assessments in Group 1. Group 2 showed a significant decrement in proteinuria (p=0.003) and serum creatinine (p=0.01) at the end of the study. PGE2 decreased significantly when compared with the initial value (p=0.02). CONCLUSION: Captopril plus usual treatment, improved serum creatinine and decreased proteinuria in parallel with prostaglandin E2 reduction. This effect is not related to changes in GFR or RPF. Captopril may have an immunomodulatory effect on local inflammatory processes in lupus nephritis.

Lack of association between hyperprolactinemia and soluble IL-2 receptor levels in systemic lupus erythematosus.

The aim of the study was to evaluate the association between hyperprolactinemia and T lymphocyte activation through the soluble IL-2 receptor (sIL-2R) in systemic lupus erythematosus (SLE) patients. Seventy SLE patients, 18 of them with hyperprolactinemia (HPRL), were compared with 18 normoprolactinemic (NPRL) patients and 10 age-matched healthy blood-bank donor women. Patients were evaluated by means of the SLE activity index (SLEDAI). Total serum IgG and sIL-2R levels were determined by an ELISA assay. Differences between sIL-2R and IgG serum levels in patients and controls were examined by Kruskal-Wallis analysis and a Spearman r correlation to determine the association between sIL-2R, IgG and prolactin (PRL) levels. IgG and sIL-2R serum levels did not differ significantly between HPRL and NPRL patients: 1827.3 (1428-2226) vs 2028.8 (1586-2467) mg/dl and 882.2 (511-1254) vs 740.1 (534-946.4) U/ml, respectively (confidence interval 95%). In the total SLE group, sIL-2R and IgG serum levels were positively associated (P = 0.0009), however, this was not the case for sIL-2R and PRL (P > 0.49). We did not demonstrate an association between HPRL and lymphocyte activation measured through serum sIL-2R in female patients with SLE.

Carpal collapse in rheumatoid arthritis--prevalence and clinical significance: a preliminary study.

OBJECTIVE: To evaluate the prevalence and clinical significance of carpal collapse in Mexican women with rheumatoid arthritis (RA). METHODS: We evaluated the carpal height ratio (CHR) of 97 women with RA and 90 healthy women. Using plain radiographs of both hands, measurements were performed by 2 radiologists in a single blind fashion. We analyzed functional class, characteristics and duration of the disease, and presence of rheumatoid factor (RF). RESULTS: CHR values of the controls were 0.49+/-0.02 (values reported in American Caucasian women are 0.54+/-0.04). Thirty-five patients had carpal collapse (defined as CHR < or = 0.43) in the right hand, 30 in the left hand, and 23 bilaterally. Carpal collapse was associated with RF seropositivity and roentgenographic degree of progression (p < 0.01), as well as with cumulative dose of steroids. As 95% of the patients were right-handed, dexterity was not apparently affected. We observed no differences in Health Assessment Questionnaire, functional class, or disease duration between patients with and those without carpal collapse. CONCLUSION: The definition of carpal collapse may have ethnic related differences. Carpal collapse is common in Mexican women with RA and it is not an indicator of functional limitations.

Glomerular expression of Fas ligand and Bax mRNA in lupus nephritis.

The current studies were carried out to determine the expression of Fas ligand and Bax in kidneys from lupus nephritis as possible indicators of apoptosis. Twenty-four kidney biopsies from patients with lupus nephritis and 30 normal controls were studied for FasL and Bax gene expression by fluorescent in situ hybridization. Seventy percent of the lupus biopsies displayed FasL or Bax mRNAs. These genes were mainly expressed in biopsies with higher activity indices. In contrast, neither of these mediators was detected in normal glomeruli. These data suggest that FasL and Bax are up-regulated in lupus nephritis and may play a pathogenic role through apoptotic cascades.

High serum prolactin levels in asymptomatic HIV-infected patients and in patients with acquired immunodeficiency syndrome.

Prolactin (PRL) is an immunostimulatory hormone that is increased in serum of patients with systemic lupus erythematosus (SLE). On the other hand, SLE and AIDS patients share some clinical and immunologic manifestations and probably share similar pathogenic factors and etiology. Based on the above, we decided to investigate the serum PRL levels in 22 asymptomatic HIV-infected patients, 32 patients with AIDS, 9 seronegative homosexual men, and 66 healthy controls. Antibodies to HIV were determined by a micro-ELISA system and by HIV-1 Western blot. Serum PRL was assayed by monoclonal antibodies. Serum PRL levels in the control group were 5.07 +/- 1.36 ng/ml and in the seronegative homosexual men were 5.81 +/- 1.45 ng/ml. Serum PRL levels in asymptomatic HIV-infected patients were 9.22 +/- 3.3 ng/ml and in AIDS patients were 10.26 +/- 2.5 ng/ml (P < 0.01 and P < 0.001, respectively, for both groups when compared to healthy controls). The difference between seronegative homosexual men and AIDS patients was P < 0.05. In the present study we found that serum PRL levels in AIDS patients are higher than in seronegative homosexual men and healthy controls; these results are in agreement with a previous published report. Since PRL is related to lymphocyte activation and lymphoproliferation, the finding may have monitoring, prognostic, and therapeutic implications.

[Lipid biosynthesis in mitochondria from leaves of olive tree (author's transl)]. / Biosynthèse de lipides dans les mitochondries de la feuille d'olivier.

Phospholipids, neutral lipids and, to a lesser extent, glycolipids are the principal lipid components of mitochondria of young olive tree leaves. These lipids are rich in palmitic and oleic acid content. The in vivo incorporation of 1-14C-acetate into the mitochondrial lipids takes place especially in phosphatidylcholine, phosphatidylethanolamine and phosphatidylglycerol. The saturated, and especially monounsaturated, acids of these lipids constitute the most actively synthesized fatty acids. In vitro, neutral lipids (mono- and diacylglycerol) and phospholipids (lysophospholipids, phosphatidylglycerol and phosphatidylcholine) incorporate a major percentage of radioactivity and in them the saturated and monounsaturated fatty acids are most actively synthesized.

Isolation and characterization of subcellular organelles from young and mature leaves of olive tree.

Subcellular organelles from young and mature leaves of olive tree have been isolated by differential centrifugation of leaf homogenates, and further purified by sucrose gradient centrifugation. Chlorophyll content was used for detecting chloroplasts after both the differential and density gradient centrifugation; aricase and catalase activities for peroxisomal identification, and the antimycin A sensitive and the antimycin-insensitive NADH-cytochrome C reductase as enzyme markers for mitochondria and microsomes, respectively. Chloroplast and mitochondrial respiration were tested polarographically by measuring the oxygen evolved or consumed, respectively, in the noncyclic electron transport chain of photosynthesis with an electron acceptor, and in the respiratory chain when succinate was used as substrate. No remarkable differences were observed between organelles from young and mature leaves, suggesting that the former can be used as a suitable material to study the lipidic biosynthetic pathways of this plant.

Maternity record: initial report on a national experience (Colombia).

The International Fertility Research Program, in cooperation with the Government of Colombia, drew a random sample of urban hospitals in which obstetric deliveries take place. Data were collected on a sample of the deliveries. Hospitals were divided into six types: university, university maternity, social security and three sizes of general hospitals. These groups of hospitals are compared with respect to the proportion of high-risk patients admitted, intervention rates and perinatal mortality rates.