Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 37
Filtrar
1.
Oral Dis ; 2023 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-37877476

RESUMO

OBJECTIVE: To determine the frequency of oral squamous cell carcinoma (OSCC) associated or not with oral potentially malignant disorders (OPMD), and the epidemiological profile and traditional risk factors in Latin America. METHODS: A retrospective observational study was conducted in 17 Latin American centres. There were included cases of OSCC, analysing age, gender, OSCC and their association with previous OPMD. Clinicopathological variables were retrieved. The condition of sequential-OSCC versus OSCC-de novo (OSCC-dn) was analysed concerning the aforementioned variables. Quantitative variables were analysed using Student's t-test, and qualitative variables with chi-square. RESULTS: In total, 2705 OSCC were included with a mean age of 62.8 years old. 55.8% were men. 53.75% of the patients were smokers and 38% were common drinkers. The lateral tongue border was the most affected site (24.65%). There were regional variations in OPMD, being leukoplakia the most frequent. Of the overall 2705 OSCC cases, 81.4% corresponded to OSCC-dn, while s-OSCC were 18.6%. Regarding lip vermillion SCC, 35.7% corresponded to de novo lip SCC and 64.3% were associated with previous OPMD. CONCLUSIONS: In Latin America, OSCC-dn seems to be more frequent with regional variations of some clinical and histopathological features. Further prospective studies are needed to analyse this phenomenon.

2.
Bull Entomol Res ; 111(3): 323-330, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33243314

RESUMO

In Argentina, the mosquito Aedes aegypti (L.) (Diptera: Culicidae) is distributed from subtropical to temperate climates. Here, we hypothesized that the expansion of Ae. aegypti into colder regions is favoured by high-phenotypic plasticity and an adaptive inhibition of egg hatching at low temperatures. Thus, we investigated the hatching response of eggs of three populations: one from a subtropical region (Resistencia) and two from temperate regions (Buenos Aires City and San Bernardo) of Argentina. Eggs collected in the field were raised in three experimental colonies. F1 eggs were acclimated for 7 days prior to immersion at 7.6 or 22°C (control eggs). Five immersion temperatures were tested: 7.6, 10.3, 11.8, 14.1 and 16°C (range of mean winter temperatures of the three localities). A second immersion at 22°C was performed 2 weeks later to assess the inhibition to hatch under favourable conditions. After the first immersion, we compared the proportions of hatched eggs and dead larvae among treatment levels, whereas after the second immersion we compared the hatching response among the three populations. The factors that most influenced the egg hatching response were the geographical origin of the populations and the immersion temperature, but not the acclimation temperature. The proportions of hatching and larval mortality at low temperatures were higher for Resistencia than for Buenos Aires and San Bernardo, whereas the hatching response at ambient temperature was lower for San Bernardo than for Buenos Aires and Resistencia. The results support the hypothesis that populations from colder regions show an adaptive inhibition of egg hatching.


Assuntos
Aedes/fisiologia , Estações do Ano , Temperatura , Aclimatação , Adaptação Fisiológica , Animais , Argentina , Temperatura Baixa , Larva/crescimento & desenvolvimento , Mortalidade , Óvulo/fisiologia
3.
J Zoo Wildl Med ; 52(2): 721-725, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34130417

RESUMO

Improvac® is a gonadotropin-releasing hormone vaccine developed to reduce "boar taint" in the meat of male domestic pig. The use of Improvac for contraception of zoo and free-living animals has been increasing in recent years. This study reports the use, efficacy, and side effects of Improvac on five male sea lions. Administration of two injections of 600 µg of Improvac (gonadotropin releasing factor analogue-protein conjugate) 4-5 wk apart were delivered to two Patagonian and three California sea lions to reduce testosterone-related aggression, anorexia, and lethargy that occur during the breeding season. Behavior and physical changes were recorded for all individuals, and blood samples were taken from one Patagonian sea lion to measure plasma testosterone concentrations over time. Observations revealed a descension of the testes into the scrotum, orchitis, lameness, anorexia, and lethargy in all individuals for the first 3-5 d after the first administration of the vaccine. Plasma testosterone concentrations rose after the first dose of the vaccine and remained elevated for 1 mo, decreasing after the second injection to undetectable levels. Improvac administration can cause a peak of testosterone and breeding behavior just after the first inoculation, as previously described in swine and elephants, but has not been documented in pinnipeds. None of the treated animals in this study showed breeding behaviors during their normal breeding season (July-September).


Assuntos
Hormônio Liberador de Gonadotropina/imunologia , Leões-Marinhos , Estações do Ano , Comportamento Sexual Animal , Vacinação/veterinária , Vacinas/imunologia , Animais , Animais de Zoológico , Humanos , Imunização/veterinária , Masculino , Testosterona/sangue , Vacinas/administração & dosagem
5.
Neurogenetics ; 16(2): 97-105, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25398481

RESUMO

Spastic paraplegia type 7 (SPG7) is one of the most common forms of autosomal recessive hereditary spastic paraplegia (AR-HSP). Although over 77 different mutations have been identified in SPG7 patients, only 9 gross deletions have been reported with only a few of them being fully characterized. Here, we present a detailed description of a large homozygous intragenic SPG7 gene rearrangement involving a 5144-base pair (bp) genomic loss (c. 1450-446_1779 + 746 delinsAAAGTGCT) encompassing exons 11 to 13, identified in a Spanish AR-HSP family. Analysis of the deletion junction sequences revealed that the 5' breakpoint of this SPG7 gene deletion was located within highly homologous Alu sequences where the 3' breakpoint appears to be flanked by the core crossover hotspot instigator (chi)-like sequence (GCTGG). Furthermore, an 8-bp (AAAGTTGCT) conserved sequence at the breakpoint junction was identified, suggesting that the most likely mechanism for the occurrence of this rearrangement is by Alu microhomology and chi-like recombination-associated motif-mediated multiple exon deletion. Our results are consistent with non-allelic homologous recombination and non-homologous end joining in deletion mutagenesis for the generation of rearrangements. This study provides more evidence associating repeated elements as a genetic mechanism underlying neurodegenerative disorders, highlighting their importance in human diseases.


Assuntos
Elementos Alu , Rearranjo Gênico , Metaloendopeptidases/genética , Mutação , ATPases Associadas a Diversas Atividades Celulares , Idoso , Feminino , Homozigoto , Humanos , Masculino , Paraplegia/genética , Linhagem , Paraplegia Espástica Hereditária/genética
6.
J Med Entomol ; 52(5): 879-85, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26336247

RESUMO

In temperate and subtropical regions, populations of Aedes (Stegomyia) aegypti (L.) survive unfavorable winter conditions in the egg stage. Knowing their survival rates can be of great interest for the health authorities in charge of control activities. In this study, we analyzed the mortality of Ae. aegypti eggs exposed to the cold season as well as their hatching patterns under laboratory conditions in the city of Resistencia, Chaco, Argentina. The mortality rate was 48.6%. No statistically significant differences were observed in the mortality of eggs exposed at different sites. Hatching response differed significantly among the successive postexposure immersions, with the highest proportion of hatched eggs during the first immersion. These results show that the mortality rate of Ae. aegypti eggs exposed to the cold season in a subtropical city of Argentina was higher than those from temperate climate region. The additional mortality of eggs in our study might be related to fungal development (an unexpected event), which was not observed in research in temperate climate. The hatching pattern observed in this study ensures a rapid increase of the population at the beginning of the favorable breeding season, but it also maintains a batch with delayed hatching eggs, posing a risk for the community.


Assuntos
Aedes/fisiologia , Temperatura Baixa , Aedes/crescimento & desenvolvimento , Animais , Argentina , Longevidade , Óvulo/crescimento & desenvolvimento , Óvulo/fisiologia , Estações do Ano
7.
Artigo em Inglês | MEDLINE | ID: mdl-38881234

RESUMO

OBJECTIVE: To analyze the success rate of external cephalic version (ECV) in pregnant women with a history of previous cesarean section, as well as to describe the rate of complications associated with the procedure. METHODS: A retrospective cohort study of women who were offered an ECV at "Virgen de la Arrixaca" Clinic University Hospital (Murcia, Spain) between January 2014 and December 2023. We collected data for previous cesarean delivery, obstetric history, fetal presentation, amniotic fluid volume, ECV success rate, complications related to ECV, mode of delivery, and neonatal outcomes. The study confidently performed ECV under sedation with propofol and tocolysis with ritodrine. Univariate and multivariate analyses were conducted to compare the success rate of ECV, ECV complications, and mode of delivery between women with and without previous cesarean sections. RESULTS: Of 1116 pregnant women who were offered ECV, 911 were included in the study, with 42 having a previous cesarean section. The success rate of ECV in pregnant women with a previous cesarean section was 78.6% (adjusted odds ratio 1.18; 95% confidence interval 0.49-2.86; P = 0.708), with a low complication rate of 9.5%, such as non-reassuring fetal heart rate (7.1%) or major vaginal bleeding (2.4%). Of the women who attempted a vaginal delivery after ECV, 80.8% were successful. CONCLUSIONS: These findings support that ECV is a safe and effective option for women with a previous cesarean section, with success rates comparable to those in women without a previous cesarean section.

8.
Dalton Trans ; 52(28): 9823-9830, 2023 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-37401510

RESUMO

The dissolution rates of unirradiated UO2 and unirradiated UO2 doped with Gd2O3 were determined as a function of pH using flow-through experiments in the presence of O2(g) and bicarbonate. The dissolution rate of non-doped UO2 was very low under hyperalkaline conditions (pH 12-13) whereas it increased drastically as the pH decreased to 9. The dissolution of non-doped UO2 in the pH range of 9-13 was consistent with the oxidative dissolution mechanism already described for UO2 dissolution in the presence of bicarbonate and oxygen. XPS analysis performed on the solid after dissolution experiments at pH 10 and 13 supported the bicarbonate effect to complex UO22+ and accelerate dissolution. Moreover, UO2 doped with Gd2O3 (5 wt% and 10 wt%) showed dissolution rates as low as non-doped UO2 under hyperalkaline conditions, which were maintained throughout the pH range studied (9-13). No substantial differences in the dissolution rates between these two doping levels were found. XPS analysis evidenced a similar surface composition both at pH 10 and 13, with U(V) being the dominant oxidation state. The low dissolution rates were assumed to be a consequence of the gadolinium capacity to retard the oxidation of U(V) to U(VI). The slight increase in dissolution rates observed in the hyperalkaline region was attributed to a shift in the oxidative dissolution mechanism, in which the presence of OH- promotes the formation of soluble uranyl hydroxo complexes.

9.
J Med Entomol ; 58(4): 1733-1739, 2021 07 16.
Artigo em Inglês | MEDLINE | ID: mdl-33675644

RESUMO

The distribution of Aedes aegypti (L.) (Diptera: Culicidae) is expanding towards colder regions, which could be aided by an adaptation of the immature stages to the local thermal conditions. This study aimed to assess the developmental success at different temperatures in three populations of Ae. aegypti located across a climate gradient in Argentina. Survival to the adult stage, development time, and wing length at 14, 18.5 and 24°C were compared among three populations of Argentina: Resistencia in the subtropical region, and Buenos Aires and San Bernardo in the temperate region. Survival was similar between populations and equal to or higher than 69%, and increased at higher temperatures within the studied range. Development times were similar between populations. A negative effect of temperature was observed and the reduction of development time at increasing temperatures was stronger for males than for females. Wing lengths were negatively affected by increasing temperatures, and the reduction of wing length was stronger for females than for males. Also, the reduction of wing lengths with temperature was stronger for San Bernardo and Resistencia than for Buenos Aires, and differences between sexes were larger for Resistencia than for Buenos Aires or San Bernardo. Although the results do not evidence differences in survival and development time between temperate and tropical populations, the three populations have a higher tolerance to low temperatures than the populations from other regions.


Assuntos
Aedes/crescimento & desenvolvimento , Animais , Argentina , Clima , Feminino , Masculino , Temperatura , Asas de Animais/crescimento & desenvolvimento
10.
Ann Hum Genet ; 74(5): 463-9, 2010 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-20560922

RESUMO

Developments in quantitative PCR technologies have greatly improved our ability to detect large genome rearrangements. In particular oligonucleotide-based array comparative genomic hybridisation has become a useful tool for appropriate and rapid detection of breakpoints. In this work, we have analysed 80 samples (42 unknown CF alleles) applying three quantitative technologies (MLPA, qPCR and array-CGH) to detect recurrent as well as novel large rearrangements in the Spanish CF population. Three deletions and one duplication have been identified in five alleles (12%). Interestingly, we provide the comprehensive characterisation of the first duplication in our CF cohort. The new CFTRdupProm-3 mutation spans 35.7 kb involving the 5'-end of the CFTR gene. Additionally, the RNA analysis has revealed a cryptic sequence with a premature termination codon leading to a disrupted protein. This duplication has been identified in five unrelated families from Spain, France and Italy with all patients showing the same associated haplotype, which is further evidence for its likely common Mediterranean origin. Overall, considering this and other previous studies, CFTR rearrangements account for 1.3% of the Spanish CF alleles.


Assuntos
Regulador de Condutância Transmembrana em Fibrose Cística/genética , Fibrose Cística/genética , Análise Mutacional de DNA , Sequência de Bases , Fibrose Cística/diagnóstico , Fibrose Cística/etnologia , França , Deleção de Genes , Duplicação Gênica , Humanos , Itália , Dados de Sequência Molecular , Mutação , Reação em Cadeia da Polimerase , Espanha
11.
Acta Trop ; 212: 105678, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32853543

RESUMO

Aedes aegypti is the main vector of dengue virus in South America. In the last fifteen years, Argentina has suffered three large dengue outbreaks: one in 2009, another one in 2016 and the current 2020 outbreak, with 26,000, 66,000 and more than 43,000 confirmed cases, respectively. These outbreaks are associated with the circulation of the virus in neighboring countries due to the constant movement of people across the frontier. In 2009, the main province affected was Chaco province, with 11,037 confirmed cases (50% of total cases). Thus, the aim of this study was to characterize the temporal oviposition rate of Aedes aegypti in Resistencia, the capital city of this province, in relation to meteorological variables. Mosquitoes were sampled weekly, from April 2015 to March 2017, using ovitraps located in houses randomly selected within the urban area. Oviposition rate was evaluated by means of the total number of eggs collected per week and the proportion of positive ovitraps per week. The coefficient of variation for these two indicators was estimated for the whole study period and then compared using the Wilcoxon Pair test. A generalized linear model (GLM) was performed to infer association between meteorological variables and oviposition rate without time lag and with a time lag of 1 to 4 weeks, considering the biology of this mosquito species. Comparisons between the coefficient of variation of egg number versus the proportion of positive ovitraps showed significant differences, being the former more variable than the latter. The most significant time lag was 2 weeks for the minimum temperature. The number of Ae. aegypti eggs increased 4.05 times when the minimum temperature increased 1°C two weeks before, and decreased 0.69 times with an increase of 1 unit in relative humidity. No eggs were collected when the temperature was below 8°C. The oviposition rate was associated with the increase in the critical minimum temperature (over 8°C) and the weekly frequency of precipitation and dissociated with relative humidity. The maximum oviposition rate was recorded between November and January of both years. The GLM could not explain the relation between meteorological variables and the proportion of positive ovitraps. The peaks of Ae. aegypti egg abundance occurred simultaneously with dengue autochthonous cases recorded in Chaco province, resulting in a good indicative of the period of greatest epidemiological risk.


Assuntos
Aedes/fisiologia , Dengue/transmissão , Mosquitos Vetores/parasitologia , Oviposição/fisiologia , Animais , Argentina , Surtos de Doenças , Feminino , Umidade , Conceitos Meteorológicos
12.
Rev Esp Salud Publica ; 942020 Dec 09.
Artigo em Espanhol | MEDLINE | ID: mdl-33226015

RESUMO

OBJECTIVE: One of the adverse drug reactions (ADR) can be the Ototoxicity, either in a cochlear level or in a vestibular one. This may cause an incapacitating symptomatology due to a hearing impairment or deafness, tinnitus, or a vertiginous syndrome. The objective of this work was to analyze the notifications of ototoxic ADRs registered in the FEDRA database of the Spanish Pharmacovigilance System for Medicinal products for Human Use (SEFV-H), manifested as tinnitus, describing epidemiological and prognostic factors, as well as active principles and associated therapeutic groups. METHODS: An observational retrospective study based on the incoming registers in the FEDRA database of the SEFV-H, with tinnitus symptomatology due to ototoxicity between 1984 and 2017 has been carried out. SPSS v.20.0 program has been used for the descriptive and inferential statistics searching elements related to the emergence, seriousness or recuperation of the tinnitus. RESULTS: A total of 662 patients notifications were obtained with 899 suspected drugs. 64% of the patients were women. The average age was 55.8 years old. An 8.5% of the tinnitus were classified as serious, meaning a significant and persistent disability. Evaluating the causality through the modified Karch-Lasagna algorithm (SEFV-H algorithm), a causal group credible or well defined, was discovered in 48.6%. In the ATC ranking, the most frequent group of cause drugs was the N, nervous system. It was concluded, among others, that the seriousness is more significant in men and that the elder group have a great influence in the tinnitus recovery. CONCLUSIONS: The appearance of tinnitus brought on by medical ototoxicity may determine an important limitation on the patient. A vestibular and cochlear function monitoring must be carried out on patients under treatment with high ototoxicity drugs. The task of the pharmacovigilance seems to be essential, by spreading its results and stimulating the ADR notifications in order to identify pharmacological threats.


OBJETIVO: Una de las reacciones adversas del consumo de fármacos puede ser la ototoxicidad, tanto a nivel coclear como vestibular. Esto puede producir una clínica incapacitante por hipoacusia o sordera, acúfenos o tinnitus, o bien un síndrome vertiginoso. El objetivo de este trabajo fue analizar las notificaciones de RAM ototóxicas registradas en la base de datos FEDRA del Sistema Español de Farmacovigilancia de medicamentos de uso humano (SEFV-H), manifestadas como acúfeno, describiendo factores epidemiológicos y pronósticos, así como principios activos y grupos terapéuticos asociados. METODOS: Se realizó un estudio observacional retrospectivo sobre los registros de la base de datos FEDRA del SEFV-H, con sintomatología de acúfenos por ototoxicidad entre los años 1984 y 2017. Se usó el programa SPSS v.20.0. para la estadística descriptiva e inferencial, buscando factores relacionados con la aparición, gravedad o recuperación del acúfeno. RESULTADOS: Se obtuvieron un total de 662 notificaciones de pacientes con 899 fármacos sospechosos. Un 64% de los pacientes eran mujeres. La edad media fue de 55,8 años. Un 8,5% de los acúfenos se etiquetaron como graves, suponiendo una discapacidad persistente o significativa. Evaluando la causalidad con el algoritmo de Karch-Lasagna modificado o el algoritmo del SEFV-H, se encontró una asociación causal probable o definida en el 48,6% de los casos. En la clasificación ATC, el grupo más frecuente de fármacos causantes fue el N (sistema nervioso). Se obtuvo, entre otros datos, que la gravedad era mayor significativamente en hombres y que el grupo de edad influía en la recuperación del acúfeno. CONCLUSIONES: La aparición de acúfenos por una ototoxicidad medicamentosa puede condicionar una limitación importante en el paciente. Se debe realizar una monitorización de la función vestibular y coclear en pacientes sometidos a tratamientos con potencial ototóxico. La labor de la farmacovigilancia se muestra fundamental, debiéndose difundir sus resultados y estimular las notificaciones de las reacciones adversas a medicamentos para identificar los riesgos farmacológicos.


Assuntos
Sistemas de Notificação de Reações Adversas a Medicamentos/estatística & dados numéricos , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Farmacovigilância , Zumbido/induzido quimicamente , Adulto , Idoso , Algoritmos , Bases de Dados Factuais , Pessoas com Deficiência , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Preparações Farmacêuticas , Estudos Retrospectivos , Espanha/epidemiologia
13.
J Vis Exp ; (160)2020 06 06.
Artigo em Inglês | MEDLINE | ID: mdl-32568226

RESUMO

External cephalic version (ECV) is an effective procedure for reducing the number of cesarean sections. To date, there is no video publication showing the methodology of this procedure. The main objective is to show how to perform ECV with a specific protocol with tocolysis before the procedure and analgesia. Moreover, we describe and analyze the factors associated with successful ECV, and also compare to deliveries in the general pregnant population. A retrospective and descriptive analysis of ECV carried out at the Hospital Clinico Universitario Virgen de la Arrixaca in Murcia (Spain) between 1/1/2014 and 12/31/2018 was assessed. The latest data available of labor deliveries in the local center, which is the biggest maternity department in Spain, were from 2018. 320 patients were recruited and 3 pregnant women were lost during the study. ECV was carried out at 37±3 weeks gestation. ECV was successful in 82.5% (N=264). 19 complications were reported (5.9%): 8 vaginal bleeding (2.5%), 9 fetal bradycardia (2.8%), 1 preterm rupture of membranes (0.3%) and 1 cord prolapse (0.3%). A previous vaginal delivery increases the success rate of ECV ORadjusted=3.03 (1.62-5.68). Maternal Body Mass Index (BMI) affects the success of ECV ORadjusted=0.94 (0.89-0.99). Patients with BMI>40 kg/m2 have an ORadjusted=0.09 (0.009-0.89) compared with those with BMI <25 kg/m2. If ECV was successful, the cesarean delivery index is 22.2% (17.5-27.6%), the eutocic delivery index is 52.1% (46.1-58.1%) and the instrumented vaginal delivery index is 25.7% (20.7-31.2%). There are no differences in cesarean and eutocic delivery indexes after successful ECV. However, a successful ECV is associated with a 6.29% increase in the instrumented delivery rate (OR=1.63). ECV is an effective procedure to reduce the number of cesarean sections for breech presentations. Maternal BMI and previous vaginal delivery are associated with ECV success. Successful ECV does not modify the usual delivery pattern.


Assuntos
Versão Fetal/métodos , Adulto , Apresentação Pélvica/cirurgia , Cesárea/estatística & dados numéricos , Feminino , Humanos , Recém-Nascido , Gravidez , Estudos Retrospectivos , Segurança , Versão Fetal/efeitos adversos
14.
J Cyst Fibros ; 8(1): 47-9, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18938114

RESUMO

So far, more than 1500 mutations have been reported in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Mutational spectrum varies in accordance with geographic and/or ethnic origin. In this study, we have analyzed seven common CF mutations (p.F508del, p.G542X, p.R1162X, p.N1303K, p.R334W, p.R553X and c.3120+1G>A) taking into account the ethnic origin of the Cuban population which is mainly influenced by Spanish and sub-Sahara African contribution. All but p.N1303K have been detected in our patients, the p.F508del being the most prevalent (37.9%). Overall, six mutations showed frequencies above 1% accounting for 55.5% of the Cuban CF alleles.


Assuntos
Fibrose Cística/genética , Mutação/genética , Cuba , Análise Mutacional de DNA , Frequência do Gene , Variação Genética , Genética Populacional , Humanos
15.
J Hazard Mater ; 150(2): 279-84, 2008 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-17531378

RESUMO

Selenium is a toxic element with a relatively high mobility in the natural waters. Iron oxy-hydroxides might play an important role in the migration of this element as well as on its removal from contaminated water. In this work we study the interaction of Se(IV), and Se(VI) with natural iron oxides hematite and goethite through two series of batch experiments at room temperature. In the first series, sorption as a function of initial selenium concentration is studied and the results have been fitted with Langmuir isotherms. In a second series of experiments, sorption is studied as a function of pH, being the main trend an increase of the sorption at acidic pH. The variation of the sorption with pH has been modelled with a triple layer surface complexation model and using the FITEQL program. The experimental data have been modelled considering for the Se(IV) the formation of the FeOSe(O)O(-) complex onto the hematite surface, and a mixture of FeOSe(O)O(-), and FeOSe(O)OH onto the goethite surface. For Se(VI) the surface complex considered is FeOH(2)(+)-SeO(4)(2-) on both goethite and hematite.


Assuntos
Poluentes Ambientais/química , Compostos Férricos/química , Óxido Ferroso-Férrico/química , Compostos de Ferro/química , Selênio/química , Gerenciamento de Resíduos/métodos , Adsorção , Poluentes Ambientais/isolamento & purificação , Concentração de Íons de Hidrogênio , Minerais , Selênio/isolamento & purificação
16.
ISA Trans ; 80: 491-502, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29866578

RESUMO

A novel kinematic formation controller based on null-space theory is proposed to transport a cable-suspended payload with two rotorcraft UAVs considering collision avoidance, wind perturbations, and properly distribution of the load weight. An accurate 6-DoF nonlinear dynamic model of a helicopter and models for flexible cables and payload are included to test the proposal in a realistic scenario. System stability is demonstrated using Lyapunov theory and several simulation results show the good performance of the approach.

17.
J Hazard Mater ; 353: 431-435, 2018 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-29702458

RESUMO

This work determines the capacity of uranophane, one of the long-term uranyl secondary solid phases formed on the spent nuclear fuel (SNF), to retain radionuclides (cesium and strontium) released during the dissolution of the SNF. Sorption was fast in both cases, and uranophane had a high sorption capacity for both radionuclides (maximum sorption capacities of 1.53·10-5 mol m-2 for cesium and 3.45·10-3 mol m-2 for strontium). The high sorption capacity of uranophane highlights the importance of the formation of uranyl silicates as secondary phases during the SNF dissolution, especially in retaining the release of radionuclides not retarded by other mechanisms such as precipitation.

18.
J Hazard Mater ; 141(3): 575-80, 2007 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-16978766

RESUMO

In this work the sorption of As(III) and As(V) on different natural iron oxides (hematite, magnetite, and goethite) has been studied as a function of different parameters. The sorption kinetics for the three iron oxides shows that equilibrium is reached in less than 2 days and the kinetics of sorption seems to be faster for goethite and magnetite than for hematite. The variation of the arsenic sorbed on the three different sorbents as a function of the equilibrium arsenic concentration in solution has been fitted with a non-competitive Langmuir isotherm. The main trend observed in the variation of the arsenic sorbed with pH is the decrease of the sorption on the three sorbents at alkaline pH values, which agrees with results found in the literature. Highest As(III) sorption was observed on hematite surface in all the pH range compared to goethite and magnetite. Natural minerals studied in this work had similar sorption capacities for arsenic than synthetic sorbents.


Assuntos
Arsênio/química , Poluentes Ambientais/química , Compostos Férricos/química , Óxido Ferroso-Férrico/química , Compostos de Ferro/química , Adsorção , Arsênio/isolamento & purificação , Poluentes Ambientais/isolamento & purificação , Concentração de Íons de Hidrogênio , Minerais , Gerenciamento de Resíduos/métodos
19.
J Hazard Mater ; 147(3): 726-31, 2007 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-17383093

RESUMO

In the high level nuclear waste repository concept, spent nuclear fuel is designed to be encapsulated in steel canisters. Thus, it is necessary to study the influence of the steel and/or its corrosion products on the behaviour of the radionuclides released from the fuel. In this sense, the main objective of this work is to contribute to the knowledge of the influence of the steel and/or its corrosion products on the uranium(VI) retention. To this aim, magnetite (Fe(3)O(4)) has been generated by anaerobic steel corrosion in an autoclave reactor at an overpressure of 8atm of H(2)(g). After characterisation by X-ray diffraction (XRD), the obtained corroded steel coupons were contacted, at two different H(2)(g) pressures (1atm and 7.6atm), with a U(VI) solution. The evolution of the uranium concentration in solution is determined and a study of the composition of the coupons at the end of the experiments is carried out. The main conclusion obtained from this work is that magnetite generated on a steel coupon is able not only to retain uranium via sorption, but also to reduce hexavalent to tetravalent uranium in a higher extent than commercial magnetite, thus, providing an effective retardation path to the migration of uranium (and, potentially, other actinides) out of the repository.


Assuntos
Óxido Ferroso-Férrico/química , Resíduos Radioativos , Aço/química , Urânio/química , Corrosão , Soluções , Fatores de Tempo , Urânio/metabolismo
20.
J Neurol Sci ; 358(1-2): 422-7, 2015 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-26403765

RESUMO

Spastic paraplegia type 10 (SPG10) is a rare form of autosomal dominant hereditary spastic paraplegia (AD-HSP) due to mutations in KIF5A, a gene encoding the neuronal kinesin heavy-chain involved in axonal transport. KIF5A mutations have been associated with a wide clinical spectrum, ranging from pure HSP to isolated peripheral nerve involvement or complicated HSP phenotypes. Most KIF5A mutations are clustered in the motor domain of the protein that is necessary for microtubule interaction. Here we describe two Spanish families with an adult onset complicated AD-HSP in which neurological studies revealed a mild sensory neuropathy. Intention tremor was also present in both families. Molecular genetic analysis identified two novel mutations c.773 C>T and c.833 C>T in the KIF5A gene resulting in the P258L and P278L substitutions respectively. Both were located in the highly conserved kinesin motor domain of the protein which has previously been identified as a hot spot for KIF5A mutations. This study adds to the evidence associating the known occurrence of mild peripheral neuropathy in the adult onset SPG10 type of AD-HSP.


Assuntos
Cinesinas/genética , Doenças do Sistema Nervoso Periférico/genética , Paraplegia Espástica Hereditária/genética , Adulto , Idade de Início , Idoso , Humanos , Masculino , Mutação , Linhagem , Doenças do Sistema Nervoso Periférico/fisiopatologia , Espanha , Paraplegia Espástica Hereditária/fisiopatologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA