843 research outputs found
Comparative study of the performance of three cross-flow ceramic membranes for water treatment
Several tests using water as effluent are used to analyse the performance of three types of microfiltration cross-flow ceramicmembranes. Two of these membranes are commercial (Atech and Membralox/US Filter) and the third one is experimental.The main differences between them lie in their chemical composition (different origin of raw materials) and in their manufacturingprocess. The results presented here show the dominant effect of the filtering and the gel layer. Both are formed during operationacting as equalising agent between the three membranes. The membranes tested have similar performances in cross-flowoperation, although permeability rates for the membrane Membralox/US Filter were about 15% higher. This increase might be due to the smoother surface formed by a second filtering ultrafiltration layer (0.01 ìm) of 10 ìm width, which probably contributes to a decrease in the thickness of the gel layer formed during operation. Using specific raw materials (non-industrial) as well as a second ultrafiltration layer improves the results in operation (performances and cleaning intervals). However, they are uneconomical because of the extra costs involved.In conclusion, low-cost membranes can achieve similar results to the commercial and more expensive ones opening up their application to new uses and emergent markets
Linezolid: idoneidad de prescripción y afectación de la función renal y hematológica
The objective of the study was to evaluate the suitability of linezolid prescription, incidence of thrombocytopenia incritically ill patients and its infl uence on critical ill patients with renal disorder before the linezolid treatment. Weobserved that the 37.5% of linezolid prescriptions were in Non-Approved Indications in Spain (NAIS). The incidenceof thrombocytopenia was 5.9%. We observed a signifi cant improvement in renal function of patients after two weeks oflinezolid treatment (p=0.024). The incidence of thrombocytopenia was similar to describe in bibliography. It seems tobe necessary approved news indications in Spain.El objeto de este estudio fue evaluar la idoneidad de prescripción de linezolid y si ésta se ajusta a las indicacionesaprobadas en España (IAE), la incidencia de trombocitopenia en pacientes críticos y la infl uencia de linezolid eneste tipo de pacientes con función renal alterada previamente a la instauración del tratamiento con dicho antibiótico.Se recogieron retrospectivamente datos clínicos y analíticos, observando que el 37.5% de las prescripcionesde linezolid eran en indicaciones no aprobadas en España (INAE), una incidencia de trombocitopenia del 5.9% yuna mejora signifi cativa de la función renal (p=0.024) tras dos semanas de tratamiento con linezolid. La incidenciade trombocitopenia en nuestro estudio fue similar a la descrita en la bibliografía. Parece necesario replantearse laampliación de las INAE
Evaluación y rehabilitación neuropsicológica en oncología pediátrica.
Objetivo. El presente trabajo tiene como objetivo el estudio de los efectos neuropsicológicos a largo plazo del cáncer infantil y sus tratamientos así como plantear propuestas para la rehabilitación cognitiva. Método. El método ha consistido en una revisión sistemática de los resultados en la literatura científica acerca de los efectos de la quimioterapia y la radioterapia sobre el SNC y en las funciones cognitivas y conductuales detectados a través de estudios de neuroimagen como calcificaciones y cambios en la sustancia blanca. Presentamos, además, el protocolo de evaluación neuropsicológica ejemplificado con un diagnóstico frecuente que presenta deterioro generalizado. Proponemos un programa de rehabilitación neuropsicológica basado en el Attention Process Training (APT) de Mateer y Sohlberg. Resultado. La radioterapia craneal y el metotrexato producen alteraciones generalizadas que se reflejan en déficit neuropsicológicos: CI, atención, memoria, habilidades académicas y motoras. Conclusiones. El avance en los tratamientos ha supuesto la disminución del número e intensidad de las secuelas. No obstante, sigue siendo frecuente que en los tumores del SNC y en las leucemias aparezcan alteraciones cognitivas y conductuales. La evaluación neuropsicológica continua y los modelos de sustancia blanca nos ayudan a entender estos efectos a largo plazo. Asimismo, esta evaluación es fundamental para diagnosticar los déficit evitando falsas atribuciones y expectativas inadecuadas. Destacamos la necesidad de una unidad de seguimiento y del trabajo interdisciplinario para promover la calidad de vida de los niños con cáncer
Cavitation of Electrons Bubbles in Liquid Helium Below saturation Pressure
We have used a Hartree-type electron-helium potential together with a density
functional description of liquid He and He to study the explosion of
electron bubbles submitted to a negative pressure. The critical pressure at
which bubbles explode has been determined as a function of temperature. It has
been found that this critical pressure is very close to the pressure at which
liquid helium becomes globally unstable in the presence of electrons. It is
shown that at high temperatures the capillary model overestimates the critical
pressures. We have checked that a commonly used and rather simple
electron-helium interaction yields results very similar to those obtained using
the more accurate Hartree-type interaction. We have estimated that the
crossover temperature for thermal to quantum nucleation of electron bubbles is
very low, of the order of 6 mK for He.Comment: 22 pages, 9 figure
A comparison of genomic profiles of complex diseases under different models
Background: Various approaches are being used to predict individual risk to polygenic diseases from data provided
by genome-wide association studies. As there are substantial differences between the diseases investigated, the data
sets used and the way they are tested, it is difficult to assess which models are more suitable for this task.
Results: We compared different approaches for seven complex diseases provided by the Wellcome Trust Case
Control Consortium (WTCCC) under a within-study validation approach. Risk models were inferred using a variety of
learning machines and assumptions about the underlying genetic model, including a haplotype-based approach with
different haplotype lengths and different thresholds in association levels to choose loci as part of the predictive
model. In accordance with previous work, our results generally showed low accuracy considering disease heritability
and population prevalence. However, the boosting algorithm returned a predictive area under the ROC curve (AUC)
of 0.8805 for Type 1 diabetes (T1D) and 0.8087 for rheumatoid arthritis, both clearly over the AUC obtained by other
approaches and over 0.75, which is the minimum required for a disease to be successfully tested on a sample at risk,
which means that boosting is a promising approach. Its good performance seems to be related to its robustness to
redundant data, as in the case of genome-wide data sets due to linkage disequilibrium.
Conclusions: In view of our results, the boosting approach may be suitable for modeling individual predisposition to
Type 1 diabetes and rheumatoid arthritis based on genome-wide data and should be considered for more in-depth
research.This work was supported by the Spanish Secretary of Research, Development
and Innovation [TIN2010-20900-C04-1]; the Spanish Health Institute Carlos III
[PI13/02714]and [PI13/01527] and the Andalusian Research Program under
project P08-TIC-03717 with the help of the European Regional Development
Fund (ERDF). The authors are very grateful to the reviewers, as they believe that
their comments have helped to substantially improve the quality of the paper
Toll-like receptor polymorphisms and cerebral malaria: <it>TLR2 </it>Δ22 polymorphism is associated with protection from cerebral malaria in a case control study
<p>Abstract</p> <p>Background</p> <p>In malaria endemic areas, host genetics influence whether a <it>Plasmodium falciparum</it>-infected child develops uncomplicated or severe malaria. TLR2 has been identified as a receptor for <it>P. falciparum</it>-derived glycosylphosphatidylinositol (GPI), and polymorphisms within the TLR2 gene may affect disease pathogenesis. There are two common polymorphisms in the 5' un-translated region (UTR) of TLR2, a 22 base pair deletion in the first unstranslated exon (Δ22), and a GT dinucleotide repeat in the second intron (GTn).</p> <p>Methods</p> <p>These polymorphisms were examined in a Ugandan case control study on children with either cerebral malaria or uncomplicated malaria. Serum cytokine levels were analysed by ELISA, according to genotype and disease status. In vitro TLR2 expression was measured according to genotype.</p> <p>Results</p> <p>Both Δ22 and GTn polymorphisms were highly frequent, but only Δ22 heterozygosity was associated with protection from cerebral malaria (OR 0.34, 95% confidence intervals 0.16, 0.73). In vitro, heterozygosity for Δ22 was associated with reduced pam3cys inducible TLR2 expression in human monocyte derived macrophages. In uncomplicated malaria patients, Δ22 homozygosity was associated with elevated serum IL-6 (<it>p </it>= 0.04), and long GT repeat alleles were associated with elevated TNF (<it>p </it>= 0.007).</p> <p>Conclusion</p> <p>Reduced inducible TLR2 expression may lead to attenuated pro-inflammatory responses, a potential mechanism of protection from cerebral malaria present in individuals heterozygous for the TLR2 Δ22 polymorphism.</p
Severe Plasmodium falciparum Malaria Is Associated with Circulating Ultra-Large von Willebrand Multimers and ADAMTS13 Inhibition
Plasmodium falciparum infection results in adhesion of infected erythrocytes to blood vessel endothelium, and acute endothelial cell activation, together with sequestration of platelets and leucocytes. We have previously shown that patients with severe infection or fulminant cerebral malaria have significantly increased circulatory levels of the adhesive glycoprotein von Willebrand factor (VWF) and its propeptide, both of which are indices of endothelial cell activation. In this prospective study of patients from Ghana with severe (n = 20) and cerebral (n = 13) P. falciparum malaria, we demonstrate that increased plasma VWF antigen (VWF∶Ag) level is associated with disproportionately increased VWF function. VWF collagen binding (VWF∶CB) was significantly increased in patients with cerebral malaria and severe malaria (medians 7.6 and 7.0 IU/ml versus 1.9 IU/ml; p<0.005). This increased VWF∶CB correlated with the presence of abnormal ultra-large VWF multimers in patient rather than control plasmas. Concomitant with the increase in VWF∶Ag and VWF∶CB was a significant persistent reduction in the activity of the VWF-specific cleaving protease ADAMTS13 (∼55% of normal; p<0.005). Mixing studies were performed using P. falciparum patient plasma and normal pooled plasma, in the presence or absence of exogenous recombinant ADAMTS13. These studies demonstrated that in malarial plasma, ADAMTS13 function was persistently inhibited in a time-dependent manner. Furthermore, this inhibitory effect was not associated with the presence of known inhibitors of ADAMTS13 enzymatic function (interleukin-6, free haemoglobin, factor VIII or thrombospondin-1). These novel findings suggest that severe P. falciparum infection is associated with acute endothelial cell activation, abnormal circulating ULVWF multimers, and a significant reduction in plasma ADAMTS13 function which is mediated at least in part by an unidentified inhibitor
Vitamin D supplementation and breast cancer prevention : a systematic review and meta-analysis of randomized clinical trials
In recent years, the scientific evidence linking vitamin D status or supplementation to breast cancer has grown notably. To investigate the role of vitamin D supplementation on breast cancer incidence, we conducted a systematic review and meta-analysis of randomized controlled trials comparing vitamin D with placebo or no treatment. We used OVID to search MEDLINE (R), EMBASE and CENTRAL until April 2012. We screened the reference lists of included studies and used the “Related Article” feature in PubMed to identify additional articles. No language restrictions were applied. Two reviewers independently extracted data on methodological quality, participants, intervention, comparison and outcomes. Risk Ratios and 95% Confident Intervals for breast cancer were pooled using a random-effects model. Heterogeneity was assessed using the I2 test. In sensitivity analysis, we assessed the impact of vitamin D dosage and mode of administration on treatment effects. Only two randomized controlled trials fulfilled the pre-set inclusion criteria. The pooled analysis included 5372 postmenopausal women. Overall, Risk Ratios and 95% Confident Intervals were 1.11 and 0.74–1.68. We found no evidence of heterogeneity. Neither vitamin D dosage nor mode of administration significantly affected breast cancer risk. However, treatment efficacy was somewhat greater when vitamin D was administered at the highest dosage and in combination with calcium (Risk Ratio 0.58, 95% Confident Interval 0.23–1.47 and Risk Ratio 0.93, 95% Confident Interval 0.54–1.60, respectively). In conclusions, vitamin D use seems not to be associated with a reduced risk of breast cancer development in postmenopausal women. However, the available evidence is still limited and inadequate to draw firm conclusions. Study protocol code: FARM8L2B5L
Allelic Variants of Melanocortin 3 Receptor Gene (MC3R) and Weight Loss in Obesity: A Randomised Trial of Hypo-Energetic High- versus Low-Fat Diets
INTRODUCTION: The melanocortin system plays an important role in energy homeostasis. Mice genetically deficient in the melanocortin-3 receptor gene have a normal body weight with increased body fat, mild hypophagia compared to wild-type mice. In humans, Thr6Lys and Val81Ile variants of the melanocortin-3 receptor gene (MC3R) have been associated with childhood obesity, higher BMI Z-score and elevated body fat percentage compared to non-carriers. The aim of this study is to assess the association in adults between allelic variants of MC3R with weight loss induced by energy-restricted diets. SUBJECTS AND METHODS: This research is based on the NUGENOB study, a trial conducted to assess weight loss during a 10-week dietary intervention involving two different hypo-energetic (high-fat and low-fat) diets. A total of 760 obese patients were genotyped for 10 single nucleotide polymorphisms covering the single exon of MC3R gene and its flanking regions, including the missense variants Thr6Lys and Val81Ile. Linear mixed models and haplotype-based analysis were carried out to assess the potential association between genetic polymorphisms and differential weight loss, fat mass loss, waist change and resting energy expenditure changes. RESULTS: No differences in drop-out rate were found by MC3R genotypes. The rs6014646 polymorphism was significantly associated with weight loss using co-dominant (p = 0.04) and dominant models (p = 0.03). These p-values were not statistically significant after strict control for multiple testing. Haplotype-based multivariate analysis using permutations showed that rs3827103-rs1543873 (p = 0.06), rs6014646-rs6024730 (p = 0.05) and rs3746619-rs3827103 (p = 0.10) displayed near-statistical significant results in relation to weight loss. No other significant associations or gene*diet interactions were detected for weight loss, fat mass loss, waist change and resting energy expenditure changes. CONCLUSION: The study provided overall sufficient evidence to support that there is no major effect of genetic variants of MC3R and differential weight loss after a 10-week dietary intervention with hypo-energetic diets in obese Europeans
Standard values and relationship-specific validity of the Bielefeld Relationship Expectations Questionnaire (BFPE)
<p>Abstract</p> <p>Background</p> <p>The Bielefeld Partnership Expectations Questionnaire (BFPE) is a tool to assess attachment in the romantic relationships of adults. The attachment styles are operationalized as configuration patterns of scale scores. While convergent validity has already been investigated, discriminant validity is still lacking confirmation.</p> <p>Methods</p> <p>The present sample (n = 1509) is representative for the German population aged 18 to 50. The mean age was 34.6 years. Most of the participants lived in a relationship (77.3 %). Discriminant validity was analyzed using a marital quality questionnaire (PFB), a social support questionnaire (F-Soz-U K-14), and a life satisfaction questionnaire (FLZ).</p> <p>Results</p> <p>All the BFPE scales have a satisfying internal consistency between r = .79 and .86. Those individuals who showed a secure pattern, i.e. increased "Readiness for Self-Disclosure" and "Conscious Need for Care" as well as reduced "Fear of Rejection" experienced their partner as socially supportive, reported higher marital quality in all of its facets, and were more satisfied within the life-domains "family/children" and "relationship/sexuality". Standard values for each scale are presented.</p> <p>Conclusions</p> <p>The BFPE has repeatedly been verified as a short, reliable, and valid instrument applicable to research practice with healthy individuals as well as within clinical contexts.</p
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