Biomedical subjects

Alberto Domínguez

Publications and source records attributed to Alberto Domínguez.

5 recordsLinked to original sources

PubMed2006

Event related potentials reveal differences between morphological (prefixes) and phonological (syllables) processing of words.

Behavioral measures in visual priming tasks show opposite effects for syllables and morphemes, which indicate that they are processed by two independent systems. We used event related potentials (ERPs) to explore two priming situations in Spanish: prefix related words (reacción-REFORMA [reaction-reform]), in which prime and target words shared a first syllable that was also a prefix, and syllable related words (regalo-REFORMA [gift-reform.]), in which the shared first syllable was a pseudoprefix in the prime word. Prefix related pairs, unlike syllable related pairs, evoked a very early positivity in reaction to the target (at 150-250ms window), suggesting that the prefix information is immediately available, at a prelexical stage. By contrast, syllable related pairs showed a larger N400 effect. This late negativity may be caused by lateral inhibition among lexical candidates activated in the lexicon by the prime's first syllable.

Adolescent↗

PubMed2004

Event-related brain potentials elicited by morphological, homographic, orthographic, and semantic priming.

The morphological structure of words, in terms of their stem morphemes and affixes, could influence word access and representation in lexical memory. Three experiments were carried out to explore the attributes of event-related potentials evoked by different types of priming. Morphological priming, with pairs of words related by their stem (hijo/hija [ son/ daughter]), produced a sustained attenuation (and even a tendency to positivity) of the N400 shown by unrelated words across the three experiments. Homographic priming (Experiment 1), using pairs of words with a superficially similar stem, but without morphological or semantic relation (foco/foca [floodlight/seal]), produced an initial attenuation similar to the morphological pairs, but which rapidly tended to form a delayed N400, due to the impossibility of integration. However, orthographic priming (rasa/rana [flat/frog]) in Experiment 2 does not produce attenuation of the N400 but an effect similar to that of unrelated pairs. Experiment 3 shows that synonyms advance more slowly than morphological pairs to meaning coherence, but finally produce a more positive peak around 600 msec.

Acoustic Stimulation↗

PubMed2003

Epidemiology and risk factors of eating disorders: a two-stage epidemiologic study in a Spanish population aged 12-18 years.

OBJECTIVE: The authors studied the prevalence rates of eating disorders (ED) and their risk factors in a Spanish population aged 12-18 years. METHOD: A two-stage epidemiologic study was conducted in the province of Valencia. Educational centers, classrooms, and individuals were selected randomly. The initial sample comprised 544 subjects. During Stage 1, subjects were screened with the 40-item Eating Attitude Test and a sociodemographic questionnaire that evaluates risk factors. During Stage 2, a semistandardized clinical interview was conducted with each participant. A random control group was paired by class, age, and sex. Comorbid psychiatric disorders and partial and subclinical forms were detected using criteria in the 4th ed. of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). RESULTS: Using DSM-IV criteria, the morbidity rate was 2.91%, women comprised 5.17% of the sample, men comprised 0.77% of the sample, and the sex ratio was 6.71. Using DSM-IV criteria, including subclinical forms, the morbidity rate was 5.56%, women comprised 10.3% of the sample, men comprised 1.07% of the sample, and the sex ratio was 9.63. Six risk factors were isolated: psychiatric comorbidity, friend on a diet in the last year, desire to lose weight, desire to be less corpulent, sentimental problems, and diet in the last year. DISCUSSION: This is the first Spanish two-stage epidemiologic study to include a control group and to investigate risk factors.

Adolescent↗

PubMed2002

Human brain potentials indicate morphological decomposition in visual word recognition.

Stem homographs are pairs of words with the same orthographic description of their stem but which are semantically and morphologically unrelated (e.g. in Spanish: rata/rato (rat/moment)). In priming tasks, stem homographs produce inhibition, unlike morphologically related words (loca/loco (madwoman/madman)) which produce facilitation. An event-related potentials study was conducted to compare morphological and stem homographic priming effects. The results show a similar attenuation of the N400 component at the 350-500 ms temporal window for the two conditions. In contrast, a broad negativity occurs only for stem homographs at the 500-600 ms window. This late negativity is interpreted as the consequence of an inhibitory effect for stem homographs that delays the stage of meaning integration.

Adult↗

PubMedDate not supplied

Production of thermostable lipolytic activity by thermus species.

A quantitative screening for intra- and extracellular lipolytic activity was performed in submerged cultures of four Thermus strains using two different media (named T or D medium). Major differences in the extracellular lipolytic activity were observed in T medium, the highest values being for Thermus thermophilus HB27 and Thermus aquaticus YT1 strains (18 and 33 U/L, respectively). Two enzymes with lipase/esterase activity were identified in the four Thermus strains by zymogram analysis, with molecular weights of 34 and 62 kDa. No kinetic typification of the enzymes as primary metabolites was possible for any of the Thermus strains, because of the lack of a good fitting of the experimental lipolytic activity production rates to the Luedecking and Piret model. However, a linear relationship was found between the absolute values of biomass and total lipase/esterase activity (sum of intracellular and extracellular). For T. thermophilus HB27, an increase in the aeration rate caused the increase in the production of biomass and, particularly, intracellular lipolytic activity but the extracellular lipolytic activity was not affected except for the series with the strongest oxygen limitation. Transmission electronic microscopy revealed that T. thermophilus HB27 formed rotund bodies surrounded by a common membrane in cultures in the early stationary phase. The results suggest the occurrence of a specific mechanism of lipase/esterase secretion that might be due to the different composition and permeability of the cell membranes and those surrounding the rotund bodies.

Culture Media↗