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J Ferrer

Publications and source records attributed to J Ferrer.

At least 19 recordsLinked to original sources
PubMed2007

Fermentation and elutriation of primary sludge: effect of SRT on process performance.

A primary sludge fermentation-elutriation pilot plant was operated using in-line and side-stream schemes. The influence of solids retention time, recirculation sludge flow-rate and solids concentration on the fermentation-elutriation process performance has been assessed in this paper. The use of high elutriation flows (12% of influent flow) improved the volatile fatty acids (VFA) concentration in the effluent stream. Suspended solids removal efficiency decreased in the primary settler when the solids retention time (SRT) was increased from 4 to 8 days. Disintegration step during hydrolysis process was pointed out as the main reason for that decrease. Maximum VFA productions were achieved at SRT between 6 and 8 days at the highest elutriation flow tested for both configurations. Propionic, butyric and valeric volatile fatty acids percentage increased when total solids sludge concentrations above 23,000mgl(-1) were used. Hydrogen accumulation, causing acetogenic bacteria inhibition, was indicated as the reason for C(3)-C(5) fatty acids accumulation.

Bioreactors↗
PubMed2006

Effect of pH on biological phosphorus uptake.

An anaerobic aerobic laboratory scale sequencing batch reactor (SBR) was operated to study the effect of pH on enhanced biological phosphorus removal. Seven steady states were achieved under different operating conditions. In all of them, a slight variation in the pH value was observed during anaerobic phase. However, pH rose significantly during aerobic phase. The increase observed was due to phosphorus uptake and carbon dioxide stripping. When pH was higher than 8.2-8.25 the phosphorus uptake rate clearly decreased. The capability of Activated Sludge Model No. 2d (ASM2d) and Biological Nutrient Removal Model No. 1 (BNRM1) to simulate experimental results was evaluated. Both models successfully characterized the enhanced biological phosphorus removal performance of the SBR. Furthermore, BNRM1 also reproduced the pH variations observed and the decrease in the phosphorus uptake rate. This model includes a switch function in the kinetic expressions to represent the pH inhibition in biological processes. The pH inhibition constants related to polyphosphate storage process were obtained by adjusting model predictions to measured phosphorus concentrations. On the other hand, pH inhibition should be included in ASM2d to accurately simulate experimental phosphorus evolution observed in an A/O SBR.

Aerobiosis↗
PubMed2006

A new D-2-hydroxyacid dehydrogenase with dual coenzyme-specificity from Haloferax mediterranei, sequence analysis and heterologous overexpression.

A gene encoding a new D-2-hydroxyacid dehydrogenase (E.C. 1.1.1.) from the halophilic Archaeon Haloferax mediterranei has been sequenced, cloned and expressed in Escherichia coli cells with the inducible expression plasmid pET3a. The nucleotide sequence analysis showed an open reading frame of 927 bp which encodes a 308 amino acid protein. Multiple amino acid sequence alignments of the D-2-hydroxyacid dehydrogenase from H. mediterranei showed high homology with D-2-hydroxyacid dehydrogenases from different organisms and other enzymes of this family. Analysis of the amino acid sequence showed catalytic residues conserved in hydroxyacid dehydrogenases with d-stereospecificity. In the reductive reaction, the enzyme showed broad substrate specificity, although alpha-ketoisoleucine was the most favourable of all alpha-ketocarboxylic acids tested. Kinetic data revealed that this new D-2-hydroxyacid dehydrogenase from H. mediterranei exhibits dual coenzyme-specificity, using both NADPH and NADH as coenzymes. To date, all D-2-hydroxyacid dehydrogenases have been found to be NADH-dependent. Here, we report the first example of a D-2-hydroxyacid dehydrogenase with dual coenzyme-specificity.

Alcohol Oxidoreductases↗
PubMed2006

The dilemma of menopause and hormone replacement--a challenge for women and health-care providers: knowledge of menopause and hormone therapy in Spanish menopausal women.

BACKGROUND: An important goal in menopause research is to develop knowledge and identify interventions that strive to promote, maintain and enhance well-being for women. OBJECTIVE: To evaluate the knowledge of postmenopausal Spanish women about menopause and their knowledge of and trust in hormone replacement therapy (HRT) and to identify their sources of information and how those data are related to compliance with their prescription. STUDY DESIGN: A total of 270 symptomatic postmenopausal women were personally interviewed using a structured questionnaire, which was designed to collect information on their familiarity with medical menopause studies, the menopause and the effects of HRT, their knowledge of alternative therapies, and to identify their sources of information. RESULTS: The most well-known menopausal complaints were hot flushes, sweats, irregular menstruation, cessation of menstruation, irritability and mood changes. Following suggestions of other symptoms by the interviewer, other complaints such as vaginal dryness, insomnia and depression/anxiety were also mentioned. HRT and phytoestrogens were recognized as treatments for the climacteric by most of the women. A woman's decision to seek treatment was initiated in 77% of cases by the gynecologist, in 12% by the general practitioner, in 3% by friends/family and in 3% by books/magazines. The most frequent responses of women to the onset of menopausal symptoms were to talk with their partner (39%), to discuss it with their gynecologist (33%) or with their general practitioner (14%) and to talk with their friends/family or to read books/magazines (10%). CONCLUSIONS: Vasomotor symptoms are recognized as the main complaint during the climacteric and HRT and phytoestrogens as the main therapies. Gynecologists play an important role in assuring compliance with therapies related to the menopause.

Adult↗
PubMed2006

Elevated serum interleukin (IL)-12p40 levels in common variable immunodeficiency disease and decreased peripheral blood dendritic cells: analysis of IL-12p40 and interferon-gamma gene.

Common variable immunodeficiency disease (CVID) is a heterogeneous syndrome characterized by low immunoglobulin serum levels and recurrent bacterial infections. Several studies suggest that CVID patients have a polarized immune response towards a T helper type 1 phenotype (TH1). However, the factors causing the TH1 polarization remain to be determined in this disease. In the present study, serum interleukin (IL)-12, interferon (IFN)-gamma levels and the IL-12p40 and IFN-gamma gene were studied in CVID patients. Furthermore, we evaluate dendritic cells (DCs) compartment, myeloid dendritic cells (mDCs) and plasmocytoid dendritic cells (pDCs), which help to differentiate naive T cells preferentially into TH1 and TH2, respectively. The serum IL-12p40 subunit levels were increased significantly in CVID patients compared to healthy controls. We examined whether these elevated serum IL-12p40 levels are associated with IFN-gamma or IL-12p40 gene polymorphisms, or with new mutations in the IL-12p40 promoter gene. In our hands, no new mutations were found and gene polymorphisms frequencies in CVID patients were similar to the control population. In conclusion, the elevated serum levels of IL-12p40 found in our CVID patients were not related to these genetic variations. The DC compartment analysis did not show an imbalance between pDCs and mDCs, but revealed the presence of low numbers and percentage of both DC populations in CVID.

Blood Cell Count↗
PubMed2006

Body weight and comorbidity predict mortality in COPD patients treated with oxygen therapy.

The aim of this study was to investigate the association between clinical variables and all-cause and respiratory mortality in patients with chronic obstructive pulmonary disease (COPD) undergoing long-term oxygen therapy (LTOT). The authors retrospectively studied a historic cohort of 128 patients with COPD (126 males, mean age+/-SD 68.9+/-9.7 yrs, body mass index (BMI) 25.1+/-4.5 kg.m-2, and forced expiratory volume in one second 25.4+/-8.8% predicted), who were being treated with long-term oxygen therapy in a tertiary teaching hospital between 1992 and 1999. Comorbidity, assessed with the Charlson Index, was present in 38% of the patients. Vital status and cause of death were assessed through the population death registry. A total of 78 patients (61%) had died by the end of follow-up. Three-year survival was 55%. Death was due to respiratory causes in 77% of cases. On Cox analysis, BMI<25 kg.m-2, comorbid conditions, age>or=70 yrs and cor pulmonale were associated with all-cause mortality. The BMI and comorbidity were the only significant predictive factors when the analysis was restricted to respiratory mortality. In conclusion, body mass index<25 kg.m-2 and comorbidity were predictors of all-cause and respiratory mortality in a cohort of chronic obstructive pulmonary disease patients treated with long-term oxygen therapy. These factors should be taken into account when considering the management and prognosis of these patients.

Aged↗
PubMed2006

Calcium effect on enhanced biological phosphorus removal.

The role of calcium (Ca) in enhanced biological phosphorus removal and its possible implications on the metabolic pathway have been studied. The experience has been carried out in an SBR under anaerobic-aerobic conditions for biological phosphorus removal during 8 months. The variations of influent Ca concentration showed a clear influence on the EBPR process, detecting significant changes in Y(PO4). These Y(PO4) variations were not due to influent P/COD ratio, pH, denitrification and calcium phosphate formation. The Y(PO4) has been found to be highly dependent on the Ca concentration, increasing as Ca concentration decreases. The results suggest that high Ca concentrations produce "inert" granules of polyphosphate with Ca as a counterion that are not involved in P release and uptake. Furthermore, microbiological observations confirmed that appreciable changes in PAO and GAO populations were not observed. This behaviour could suggest a change in the bacterial metabolic pathway, with prevailing polyphosphate-accumulating metabolism (PAM) at low influent Ca concentration and glycogen-accumulating metabolism (GAM) at high concentration.

Aerobiosis↗
PubMed2006

Calibration and simulation of ASM2d at different temperatures in a phosphorus removal pilot plant.

In this work, an organic and nutrient removal pilot plant was used to study the temperature influence on phosphorus accumulating organisms. Three experiments were carried out at 13, 20 and 24.5 degrees C, achieving a high phosphorus removal percentage in all cases. The ASM2d model was calibrated at 13 and 20 degrees C and the Arrhenius equation constant was obtained for phosphorus removal processes showing that the temperature influences on the biological phosphorus removal subprocesses in a different degree. The 24.5 degrees C experiment was simulated using the model parameters obtained by means of the Arrhenius equation. The simulation results for the three experiments showed good correspondence with the experimental data, demonstrating that the model and the calibrated parameters were able to predict the pilot plant behaviour.

Calibration↗
PubMed2005

Does an educational leaflet improve self-reported adherence to therapy in osteoporosis? The OPTIMA study.

INTRODUCTION: Adherence to treatment in osteoporosis remains poor. The aim of this study was to evaluate the effects of an educational leaflet on adherence to medication and to assess the association between adherence and health-related quality of life (HRQOL). METHODS: A naturalistic, observational, multi-center, prospective study of 12 months' follow-up was performed. Consecutive post-menopausal women aged 50 years to 86 years starting treatment with raloxifene according to daily practice were enrolled from 126 primary care offices in Spain. The women were assigned to two study groups. Group A received an educational leaflet with general information about osteoporosis; group B followed current practice. To assess adherence to medication and HRQOL, the Morisky test and the EuroQoL questionnaire were administered. A total of 745 post-menopausal women (group A, n=366; group B n=379), with a mean age of 62 years, were included. RESULTS: Most patients in both study groups showed high adherence to raloxifene at the 3-month visit: 56.3% vs 62.7% for groups A and B, respectively; this proportion at the 12-month visit was 47.4% (P=0.15) and 52.5% (P=0.02), respectively. At baseline, "pain/discomfort" was the dimension showing the highest percentage of women reporting problems: 86.4% vs 83.2% in groups A and B, respectively (P=0.22). HRQOL improved in both groups throughout the study, with an overall mean increment in the EuroQoL visual analog scale (EQ VAS) of 9.2 at 12 months (P<0.01). Correlations between adherence and HRQOL were weak. After receiving an educational leaflet, young post-menopausal women suffering osteoporosis did not show improvement in adherence to therapy. HRQOL improved at 12-month follow-up under treatment. CONCLUSION: No consistent correlation between adherence and HRQOL was found.

Aged↗
PubMed2005

Optimum design and operation of primary sludge fermentation schemes for volatile fatty acids production.

This paper presents a model-knowledge based algorithm for optimising the primary sludge fermentation process design and operation. This is a recently used method to obtain the volatile fatty acids (VFA), needed to improve biological nutrient removal processes, directly from the raw wastewater. The proposed algorithm consists in a heuristic reasoning algorithm based on the expert knowledge of the process. Only effluent VFA and the sludge blanket height (SBH) have to be set as design criteria, and the optimisation algorithm obtains the minimum return sludge and waste sludge flow rates which fulfil those design criteria. A pilot plant fed with municipal raw wastewater was operated in order to obtain experimental results supporting the developed algorithm groundwork. The experimental results indicate that when SBH was increased, higher solids retention time was obtained in the settler and VFA production increased. Higher recirculation flow-rates resulted in higher VFA production too. Finally, the developed algorithm has been tested by simulating different design conditions with very good results. It has been able to find the optimal operation conditions in all cases on which preset design conditions could be achieved. Furthermore, this is a general algorithm that can be applied to any fermentation-elutriation scheme with or without fermentation reactor.

Algorithms↗
PubMed2005

Conductance oscillations in zigzag platinum chains.

Using first principles simulations we perform a detailed study of the structural, electronic, and transport properties of monatomic platinum chains, sandwiched between platinum electrodes. First, we demonstrate that the most stable atomic configuration corresponds to a zigzag arrangement that gradually straightens as the chains are stretched. Second, we find that the averaged conductance shows slight parity oscillations with the number of atoms in the chain. Additionally, the conductance of chains of fixed oscillates as the end atoms are pulled apart, due to the gradual closing and opening of conductance channels as the chain straightens.

Journal Article↗
PubMed2005

Cost/efficacy clinical trial about the use of T-tube in cadaveric donor liver transplant: preliminary results.

UNLABELLED: Biliary reconstruction is the most common cause of morbidity associated with orthotopic liver transplantation. Our objective was to assess the complications and hospital resources related to the use of a T-tube. MATERIAL AND METHODS: Among 95 liver transplants performed from October 2002 to November 2003, 84 patients were randomized to receive a T-tube or no T-tube. We analyzed all patients with a follow-up of at least of 3 months. RESULTS: Fifty-five transplants were analyzed with 8 months mean follow-up, including twenty eight with T-tube and twenty seven without a T-tube. No patient died during the follow-up. The overall rate of biliary complications was 45.4% (25/55) including 21/28 (75%) in the T-tube group and 4/27(14.8%) in the non-T-tube group (P < .0001). Complications related to T-tube extraction occurred in 48.2% (13/27), including 3 cholangitis and 10 leaks. The costs of hospital resources due to radiological studies were 5329 capital JE, Ukrainian for the T-tube group vs 5785 capital JE, Ukrainian for the non-T-tube group. The costs of hospital resources due to treatment were 28,280 capital JE, Ukrainian for the T-tube group vs 10,088 capital JE, Ukrainian for the non-T-tube group. CONCLUSIONS: Use of a T-tube during orthotopic liver transplantation does not seem justified. Biliary anastomosis stenting is followed by an increased incidence of complications, most of which are related to its use. Hospital stay, radiological studies, and cost of hospital resources are higher among the T-tube patients. Therefore its systematic use is not advisable.

Anastomosis, Surgical↗
PubMed2005

Portal vein thrombosis in liver transplantation.

In the initial experience of liver transplantation, complete thrombosis and portal vein occlusion were considered to be absolute contraindications for liver transplantation. The incidence of portal thrombosis in patients being prepared for transplantation varies between 5% and 15% according to published series. There are 2 surgical techniques to solve absent or low portal vein flow due to thrombosis. The most widely used technique is thrombectomy and the second technique is insertion of a shunt with a venous graft in the permeable portion of the superior mesenteric vein or in a vein in the splanchnic territory. Portal thrombosis recurrence rates vary among series, ranging from 0% to 25% or even 30%, depending on its extension and severity and also on time the transplantation was performed. Although overall survival is somewhat lower, there are no significant differences in most of the series when patients with portal thrombosis who underwent transplantation are compared with those without.

Humans↗
PubMed2005

One thousand liver transplants: the hospital clinic experience.

OBJECTIVES: Our goal was to study a consecutive series of 1000 liver transplants performed in our institution to evaluate the changes over time in donors, recipients, and results. PATIENTS AND METHODS: With the aim to evaluate differences between transplantation in the first period and the present period, the first consecutive 100 liver transplants performed from June 1988 to June 1990 (first period) were compared with the last consecutive 200 liver transplants performed from January 2001 to June 2003 (second period). RESULTS: Increased donor age, change in donor cerebral death etiology, and increasing numbers of grafts from alternative methods using cadaveric donors were observed in the second period. Piggy-back technique and the biliary anastomosis without a t-tube was also started in the second period. One-year actuarial patient survival was higher in the second period (84% vs 91.3%). The need for retransplantation in the overall series was 95%. One-, 5-, and 10-year actuarial retransplant survival was 67.7%, 51.3%, and 39.4%, respectively. CONCLUSIONS: Technical innovations, better understanding of donor and recipient aspects, and global improvements were the reasons for time-related improved results of liver transplantation.

Adult↗
PubMed2005

The role of potassium, magnesium and calcium in the Enhanced Biological Phosphorus Removal treatment plants.

Cations as potassium and magnesium play an important role in maintaining the stability of Enhanced Biological Phosphorus Removal (EBPR) process. In this paper potassium, magnesium and calcium behaviour in EBPR treatment plants has been studied. An ASM2d model extension which takes into account the role of potassium and magnesium in the EBPR process has been developed. Finally, a simulation of the effect on P removal of a shortage of K and Mg was studied. The experimental results showed that K and Mg play an important role in the EBPR process being cotransported with P into and out of bacterial cells. It has been observed that calcium is not involved in P release and uptake. The values of the molar ratios K/P (0.28 mol K mol P(-1)) and Mg/P (0.36 mol Mg mol P(-1)) were obtained accomplishing the charge balance, with different K/Mg mass ratios and without phosphorus precipitation. Model predictions accurately reproduced experimental data. The simulations carried out showed the important effect of the K and Mg influent concentration for P removal efficiency. The results illustrate that the proposed ASM2d model extension must be considered in order to accurately simulate the phosphorus removal process.

Aerobiosis↗
PubMed2004

Transcriptional networks controlling pancreatic development and beta cell function.

Transcription factors provide the genetic instructions that drive pancreatic development and enable mature beta cells to function properly. To understand fully how this is accomplished, it is necessary to unravel the regulatory networks formed by transcription factors acting on their genomic targets. This article discusses recent advances in our understanding of how transcriptional networks control early pancreas organogenesis, embryonic endocrine cell formation and the differentiated function of adult beta cells. We discuss how mutations in several transcription factor genes involved in such networks cause Maturity onset diabetes of the young (MODY). Finally, we propose that pancreatic gene programs might be manipulated to generate beta cells or to enhance the function of existing beta cells, thereby providing a possible treatment of different forms of diabetes.

Animals↗