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C Domingo

Publications and source records attributed to C Domingo.

At least 19 recordsLinked to original sources
PubMed2006

Carbon nanotube bundles as molecular assemblies for the detection of polycyclic aromatic hydrocarbons: surface-enhanced resonance Raman spectroscopy and theoretical studies.

In this work surface-enhanced resonance Raman spectroscopic experiments have demonstrated that metallic single-walled carbon nanotubes can be used as chemical assemblies between the pyrene analyte and the silver colloidal surface. Pyrene has been detected at concentrations lower than 10(-9) M by use of the 514.5 nm excitation laser line. A charge transfer from the surface to the nanotube characterizes the nanotube-silver surface interaction. The pyrene-nanotube interaction occurs through a pi-pi electronic stacking. Extended Hückel calculations based on a simplified molecular model for the analyte/nanotube/surface system support the experimental conclusions. The nanotube-pyrene distance is 3.4 A, and the most probable orientation for pyrene is confirmed to be plane parallel to the nanotube surface. An energy transfer from the silver surface to the nanotube/analyte system is verified.

Journal Article↗
PubMed2006

Yellow fever vaccine-associated viscerotropic disease and death in Spain.

Yellow fever vaccine-associated viscerotropic disease (YEL-AVD) is a recently described severe adverse event after yellow fever vaccination, and some cases have been reported in different countries [Anonymous. Effects of yellow fever and vaccination. Lancet 2001;358(9296):1907-9]. Herein we describe a YEL-AVD case in a young woman, who died after vaccination with 17D-204 strain. Clinical, serological and immunochemical analysis as well as virus detection, quantification, sequence analysis and cytokine release, were performed. Further investigations on yellow fever vaccine adverse events, and carefully analysis of the immune response elicited are important tasks for the future.

Adult↗
PubMed2006

Structural and texture evolution with temperature of layered double hydroxides intercalated with paramolybdate anions.

Paramolybdate-LDHs with MgAl or ZnAl cations within the layers have been prepared by the ion-exchange method from hydrotalcites with different interlayer anions (OH-, NO3(-), and terephthalate). The samples and the oxides obtained after their calcination were characterized by element chemical analysis, PXRD, FT-Raman spectroscopy, thermal analysis (TG/DTA), N2 adsorption at -196 degrees C, and SEM. The results show that layered solids with hydrotalcite-type structure were obtained in which the interlayer space is occupied by heptamolybdate with a small amount of MoO4(2-) units formed through hydrolysis of the polyanion; both oxomolybdenum species undergo a progressive distortion of the octahedral units from 50 degrees C but are roughly stable up to 250 degrees C as a consequence of the interaction between the polyanion and the brucite-like layers. This distortion is responsible for the observed decrease in the height of the gallery for samples heated in the temperature range, 50-250 degrees C, with respect to the original samples. Rehydration of the calcined solids allows recovering of their original structures and the initial values for the gallery heights. Calcination between 300 and 400 degrees C gives rise to a collapse of the layered structure, and amorphous phases are formed, in which molybdenum is both octahedrally and tetrahedrally coordinated. Crystalline magnesium and zinc molybdates (MgMoO4 and ZnMoO4) are formed at 450 and 600 degrees C, respectively. All solids have some microporosity, which decreases with increasing the calcination temperature.

Journal Article↗
PubMed2006

Detection and subtyping of dengue 1-4 and yellow fever viruses by means of a multiplex RT-nested-PCR using degenerated primers.

OBJECTIVE: Differential diagnosis of infections that cause similar diseases and may be active simultaneously in the same geographical areas is greatly needed. Dengue and yellow fever viruses (DENV and YFV) are transmitted by the same species of mosquito and both can cause haemorrhagic fever symptoms. These viruses are active mainly in regions where expensive and sophisticated technologies are not available. Our objective was to develop a simple, reliable and easy-to-perform method to detect and identify these viruses. METHODS: We slightly modified a generic RT-PCR able to detect the mentioned viruses and other members of this genus: specific primers for each one of these viruses were designed and included in the nested reaction instead of one of the generic ones. The reaction was optimized and viruses are amplified giving rise to bands of different sizes distinguishable in agarose gels. RESULTS: This test is able to detect and identify the four DENVs and YFV to a high level of sensitivity and specificity and can be used with clinical samples. This simple, reliable and easy-to-perform method able to detect and identify dengue 1-4 and YFV can be used in poor endemic countries.

DNA Primers↗
PubMed2006

Use of a short fragment of the C-terminal E gene for detection and characterization of two new lineages of dengue virus 1 in India.

Here we propose the use of a 216-nucleotide fragment located in the carboxyl terminus of the E gene (E-COOH) and a pairwise-based comparison method for genotyping of dengue virus 1 (DENV-1) strains. We have applied this method to the detection and characterization of DENV-1 in serum samples from travelers returning from the tropics. The results obtained with the typing system correlate with the results obtained by comparison of the sequences of the entire E gene of the strains. The approach demonstrates utility in plotting the distribution and circulation of different genotypes of DENV-1 and also suggests the presence of two new clades of Indian strains. The integration of the method with an online database and a typing characterization tool enhances its strength. Additionally, the analysis of the complete E gene of DENV-1 strains suggested the occurrence of a nondescribed recombination event in the China GD23-95 strain. We propose the use of this methodology as a tool for real-time epidemiological surveillance of dengue virus infections and their pathogenesis.

DNA, Viral↗
PubMed2005

Surface enhanced vibrational (IR and Raman) spectroscopy in the design of chemosensors based on ester functionalized p-tert-butylcalix[4]arene hosts.

Surface-enhanced IR (SEIR) and Raman scattering (SERS) have been employed to study the adsorption of ester functionalized tert-butyl calix[4]arenes on Ag and Au nanostructured surfaces as well as their complexes with pyrene. The influence of adsorption and complexation with pyrene on the host calixarene structure was tested for two different calixarene molecules bearing carboethoxy groups (CH(3)CH(2)COOCH(2)-) in the low rim at positions 1,3- and 1,2,3,4-. The results obtained with SEIR were compared to those obtained with SERS, to better understand the interaction mechanism of the studied calixarenes with the metallic surfaces and the ligand as well as to investigate the structure/selectivity relationship of these two surface techniques in the analysis of recognition problems in which these ester functionalized calixarene molecules are involved.

Journal Article↗
PubMed2005

Comparative study of the morphology, aggregation, adherence to glass, and surface-enhanced Raman scattering activity of silver nanoparticles prepared by chemical reduction of Ag+ using citrate and hydroxylamine.

Two different silver colloids were prepared by chemical reduction of silver nitrate with trisodium citrate and hydroxylamine hydrochloride to compare their characteristics in relation to their possible use in surface-enhanced Raman scattering (SERS) spectroscopy. The morphology and plasmon resonance of the single nanoparticles and aggregates integrating these colloids were characterized by means of UV-vis absortion spectroscopy and scanning electron microscopy, revealing important differences between each type of nanoparticle as concerns their physical properties. These metallic systems also manifested differences in the aggregation and the adherence to glass surfaces, revealing significant differences in the chemical surface properties of these nanoparticles. SERS and surface-enhanced IR also indicated the presence of interference bands which can overlap the spectra of the analyte, mainly in the case of the citrate colloid. All these differences have an important influence on the applicability of these nanostructured systems in SERS. In fact, the enhancement factor and spectral pattern of the SERS obtained by using alizarin as a molecule probe are different.

Journal Article↗
PubMed2005

Generic RT-nested-PCR for detection of flaviviruses using degenerated primers and internal control followed by sequencing for specific identification.

Flaviviruses are a widespread and numerous group of arboviruses that can cause serious illness in humans. The continuous and slow spread of certain flaviviruses, such as Dengue viruses, and the recent entry and spread of West Nile virus to the American continent, point to the need to control these infections. This control requires the use of suitable techniques for diagnostic and surveillance programmes. A generic RT-nested-PCR that is, theoretically, able to detect each member of the group has been designed. The identification of the detected virus is carried out by sequencing. The introduction of an internal control would reduce the number of false negative results and could be used to quantify the viral load in clinical samples where the method works well.

False Negative Reactions↗
PubMed2005

Surface-enhanced micro-Raman detection and characterization of calix[4]arene-polycyclic aromatic hydrocarbon host-guest complexes.

Surface-enhanced micro-Raman spectroscopy (micro-SERS) was used to detect traces of the hazardous pollutant polycyclic aromatic hydrocarbons (PAHs) pyrene and benzo[c]phenanthrene deposited onto a calix[4]arene-functionalized Ag colloidal surface. High spectral reproducibility and very low molecular detection limits (10(-8) M) were obtained by using 25,27-carboethoxy-26,28-hidroxy-p-tert-butylcalix[4]arene as host molecule. Films of immobilized aggregated Ag nanoparticles, obtained by chemical reduction with hydroxylamine, were prepared by direct adhesion on a glass surface. The influence of the aggregation degree of the initial Ag nanoparticles on the micro-SERS detection effectiveness was checked. Different relative concentrations of the host (calixarene receptor) and the guest (PAHs) were attempted in order to optimize detection of the pollutant. The obtained results indicated that the detection limit is much lower in the case of benzo[c]phenanthrene than in pyrene when exciting with the 785 nm line of a diode laser. A detailed interpretation of the Raman spectra was accomplished in order to obtain more information about the interaction mechanism of the host-guest complex, which could be useful in the future for the design of powerful detection systems.

Journal Article↗
PubMed2003

Immunological properties of a DNA plasmid encoding a chimeric protein of herpes simplex virus type 2 glycoprotein B and glycoprotein D.

A DNA plasmid containing a chimeric sequence encoding both herpes simplex virus type 2 (HSV-2) glycoprotein B (gB) and glycoprotein D (gD) external domains (pcgDB) was used to immunize BALB/c mice against genital HSV-2 infection. To determine the efficacy of this vaccine, groups of mice immunized with the pcgDB plasmid were compared with animals immunized with plasmids corresponding to the individual proteins (pcgBt or pcgDt), administered separately or in combination (pcgBt + pcgDt). We studied the response of the different mouse groups to viral challenge by analyzing clinical disease (vaginitis), serum antibody levels, as well as lymphoproliferative responses and cytokine production by spleen cells. Increased IFN-gamma levels correlated with prolonged survival in mice immunized with the plasmid pcgDB, relative to mice immunized with plasmids coding for the individual proteins alone or in combination. Our results show that immunization with the plasmid encoding the chimeric protein is advantageous over separate proteins. These findings may have important implications for the development of multivalent DNA vaccines against HSV and other complex pathogens.

Animals↗
PubMed2003

Hydrolytic stability of experimental hydroxyapatite-filled dental composite materials.

OBJECTIVES: The purpose of this study was to analyze the behavior in water, related to mechanical properties, of experimental composites for dental restoration. METHODS: The studied materials were composed of a visible-light-curing monomer mixture (Bis-GMA and TEGDMA or HEMA) and micrometric, nanometric or a mixture of both sizes hydroxyapatite particles as a reinforcing filler. Filler particles were modified with a coupling agent (citric, hydrosuccinic, acrylic or methacrylic acid or silane). The hydrolytic stability of the evaluated materials was studied through total elution and water-uptake tests. Percent net-mass variation was daily monitored and analyzed as a function of time. Mechanical performance was examined through flexural properties and Vickers hardness. Morphological surface changes were observed with scanning electron microscopy. ANOVA statistical analysis was performed (P<0.05). RESULTS: In general, the use of HEMA instead of TEGDMA did not substantially worsen the composite quality. Dental composites containing only nanometric particles of hydroxyapatite as a filler are unsuitable for clinical performance. Midway-filled composite resins loaded with micro-HAP particles, coated with citric, acrylic or methacrylic acid displayed low percent elution and water-uptake values. Mechanical properties were similar or even superior to those measured for silane treated particles. SIGNIFICANCE: More research is needed to further improve the interaction of nano-HAP particles with the polymeric matrix, either as a single filler or, preferentially, mixed with micro-HAP, that will allow to increase the total loading of reinforcing filler and, hence, to improve the mechanical properties.

Analysis of Variance↗
PubMed2003

Long-term effects of almitrine bismesylate in COPD patients with chronic hypoxaemia.

BACKGROUND: Almitrine bismesylate (AB) is a peripheral chemoreceptor agonist which is believed to improve oxygenation of COPD patients with chronic hypoxaemia, probably by improving the ventilation perfusion mismatch. We studied the long-term effects of AB in COPD patients with chronic hypoxaemia. METHODS DESIGN: Prospective, randomised, double-blind, placebo-controlled trial. SETTING: Eight hundred bed teaching hospital with a catchment population of 350,000 inhabitants. PATIENT RECRUITMENT: COPD outpatients consulting between September 95 and September 99. INCLUSION CRITERIA: (1) COPD (FEV1 < 50%). (2) PaO2 < or = 65 mmHg. (3) Stable arterial blood gases (ABG), spirometry (S) and clinical state. EXCLUSION CRITERIA: Asthma, restrictive disease, sleep apnoea syndrome, advanced renal or hepatic disease, peripheral neuropathy, use of respiratory stimulants or psychotrophic drugs. TREATMENT: AB 1 mg/kg/day (weight < 75 kg = 50 mg/day; weight > or = 75 kg = 100 mg/day) in an intermittent schedule with resting periods of 1 month after the third, 6th and 9th months during 1 year. INSTRUMENTATION: Stabilisation period: S, ABG. Run-in period: S, ABG, 6-min walking test (WT), nocturnal pulse oximetry (NP) and quality of life evaluation (CRQ). Third, 6th and 9th months: S, ABG. End of the study: S, ABG, WT, NP, CRQ. STATISTICS: ANOVA for repeated measurements. RESULTS: Two hundred and eighty-nine patients were evaluated and 81 were included in the study. Sixty-six were followed for 6 months, 53 for 9 months and 42 for 1 year. Almitrine and placebo groups did not present significant differences in ABG and S in the 6th, 9th and 12th months. Evolution in WT, NP and CRQ were similar in the two groups. No relevant side-effects were detected: only two patients stopped treatment (one placebo and one AB). CONCLUSION: In an intermittent schedule, although well tolerated, at doses of 1 mg/kg/day, AB was not effective in long-term treatment of chronic hypoxemia in COPD patients.

Aged↗
PubMed2002

Effect of soil parameters on radon entry into a building by means of the transrad numerical model.

High indoor radon concentration means an increased risk of developing lung cancer. When high radon levels are present in a dwelling, the major source is normally the soil. Therefore, it is useful to know the radon concentration field in the soil underneath a building. A steady-state two-dimensional radon transport model has been used to calculate the effect of a reference building on the soil radon concentration, and the influence of soil parameters on radon entry through a single crack in the basement. Both advective and diffusive flows are considered. Away from the building, the well-known undisturbed soil radon concentration profile has been obtained, while under the house the radon level is increased. A variability analysis around the reference site has shown that the most relevant soil parameters on the radon flux at the top of the crack are, in this case, effective diffusion coefficient, soil gas-permeability and deep soil radon concentration.

Air Pollutants, Radioactive↗
PubMed2001

Uncertainty, variability and sensitivity analysis applied to the RAGENA model of radon generation, entry and accumulation indoors.

The application of a radon model is useful to understand the processes that drive the radon gas behaviour from its sources to its accumulation indoors. Since in a given inhabited house the detailed knowledge of the values of all the parameters that affect indoor radon levels is not available, the response of the model has to be explored in a reference site in which all the parameters are supposed to be known. We call this site the reference configuration. In this paper we report on the procedure followed to carry out uncertainty, sensitivity and variability analysis of the model response for a reference configuration that corresponds to a single family multi-zone house. We have obtained from the uncertainty analysis that, assuming a normal distribution of all the input parameters with a 10% relative standard deviation (R.S.D.), the model outputs present a R.S.D. in the range 17-22%. The sensitivity analysis reflects, in general, a good behaviour of the model, in the sense that its response describes a realistic behaviour of the system. The variability analysis has shown that the model is applicable to a wide range of situations, and that the most relevant parameters for the reference configuration are: the soil gas-permeability (obtained from the mean soil grain diameter); the ventilation rate of the rooms; the air-exchange rate between the basement and room 2; the soil-indoor pressure difference; the open area; and the concrete radium content.

Journal Article↗
PubMed2001

Dental composites reinforced with hydroxyapatite: mechanical behavior and absorption/elution characteristics.

The purpose of this study was to analyze the behavior in water as well as the mechanical and surface properties of experimental composites designed for dental restoration. Studied materials were composed of a visible-light-cured monomer mixture as a matrix (bisphenol-alpha-glycidyl methacrylate with triethyleneglycol dimethacrylate or hydroxyethyl methacrylate) and either micrometric or nanometric hydroxyapatite (HA) particles as a reinforcing filler. The surface of the filler particles was modified by using different coupling agents (citric, hydroxysuccinic, acrylic, or methacrylic acid). The hydrolytic stability of the evaluated materials was studied through elution-in-water and water-uptake tests. Mechanical and surface properties were examined through the results of flexural, hardness, and surface roughness tests. Means and standard deviations were calculated for each variable. Analysis of variance and multiple comparison tests were performed. Materials containing bisphenol-alpha-glycidyl methacrylate:triethyleneglycol dimethacrylate and micrometric-HA coated with citrate, acrylate, or methacrylate displayed the most favorable results. Improvements should be obtained by increasing the total filler amount, and by the introduction of nanometric-HA filler into a micrometric-HA reinforced composite resin system.

Absorption↗
PubMed2001

The MICA region determines the first modifier locus in familial Mediterranean fever.

OBJECTIVE: Familial Mediterranean fever (FMF) is a genetically recessive inflammatory disease caused by mutations in the MEFV gene. Most patients of non-Ashkenazi Jewish ancestry or those who are homozygous for M694V manifest a severe disease course, but some express a mild form of the disease. We therefore searched for other genes which could possibly be implicated in the disease phenotype. We tested MICA (major histocompatibility complex class I chain-related gene A) because it has been associated with a number of other inflammatory disorders. METHODS: One hundred fifty FMF probands and their family members were evaluated. The MEFV gene was screened by a combination of denaturing gradient-gel electrophoresis, restriction fragment length polymorphism, and amplification refractory mutation system. The MICA transmembrane polymorphism in exon 5 was analyzed after biotin-labeled polymerase chain reaction products were loaded onto sequencing gels and subjected to autoradiography. RESULTS: The contribution of MICA to the FMF phenotype was confirmed after adjustment for the patient's ancestry and for the MEFV genotype. MEFV was individually the most important prognostic factor for the disease. However, the impact of M694V homozygosity on the age at disease onset (OR 2.3) was aggravated if patients also inherited MICA-A9 (OR 6.3). In contrast, the frequency of attacks was found to be dramatically reduced (OR 0.16) in patients with MICA-A4. CONCLUSION: We have identified the first FMF modifier locus, MICA. FMF is the first model of a Mendelian disease associated with MICA. These results clarify, at least partly, the inconsistent phenotype-MEFV correlation in FMF.

Alleles↗