Phonological awareness and quick naming of developmental dyslexia in Sekolah Dasar Inklusif Pantara, Jakarta

The weak phonological awareness and slow reaction time in word identification is a disorder that dyslexic people have in reading (Wolf and Bowers, 1999). Therefore, this study will investigate the ability of phonological awareness (phonological awareness), rapid naming (Rapid Naming) and reading ability of people with dyslexia. The subjects consisted of 4 children aged 7-8 years of dyslexia in Pantara Inclusive Elementary School, Jakarta. The four dyslexic children were compared to the control group (20 children from Kwitang 8 PSKD Pancoran Mas, Depok, who had the same age and gender as dyslexic children). The research used quantitative method with case study control design. The study was conducted with three experiments, namely: reading test, counting the number of silabel, and fast-track test. The first experiment consisted of 100 words (simple words, digraphs, diphthongs, and consonant clusters). The second experiment consisted of 48 words (24 words with illustrations and 24 words with trisilabik). All words are from the 10,000 words that have the highest frequency in the Indonesian linguistic corpus (Indonesianwac). The third test is 50 RAN letters (Pennington et al., 2001). Results showed that persons with dyslexia had a lower ability than the control group on all three tests. Dyslexic children tend to perform sound recovery, eliminate phonemes and swap words with nonwords and slow reaction times. Based on the results obtained, 2 dyslexic children data support double deficit hypothesis Wolf and Bowers (1999) because dyslexic children show phonological deficits and rapid naming deficits.

Spatio-temporally specific transcranial magnetic stimulation to test the locus of perceptual decision making in the human brain

Previous research modeling EEG, fMRI and behavioral data has identified three spatially distributed brain networks that activate in temporal sequence, and are thought to enable perceptual decision-making during face-versus-car categorization. These studies have linked late activation (>300ms post stimulus onset) in the lateral occipital cortex (LOC) to object discrimination processes. We applied paired-pulse transcranial magnetic stimulation (ppTMS) to LOC at different temporal latencies with the specific prediction, based on these studies, that ppTMS beginning at 400ms after stimulus onset would slow reaction time (RT) performance. Thirteen healthy adults performed a two-alternative forced choice task selecting whether a car or face was present on each trial amidst visual noise pre-titrated to approximate 79% accuracy. ppTMS, with pulses separated by 50ms, was applied at one of five stimulus onset asynchronies: -200, 200, 400, 450, or 500ms, and a sixth no-stimulation condition. As predicted, TMS at 400ms resulted in significant slowing of RTs, providing causal evidence in support of LOC contribution to perceptual decision processing. In addition, TMS delivered at -200ms resulted in faster RTs, indicating early stimulation may result in performance enhancement. These findings build upon correlational EEG and fMRI observations and demonstrate the use of TMS in predictive validation of psychophysiological models.

Development of a xylitol biosensor composed of xylitol dehydrogenase and diaphorase

In preparation for the development of a xylitol biosensor, the xylitol dehydrogenase of Candida tropicalis IFO 0618 was partially purified and characterized. The optimal pH and temperature of the xylitol dehydrogenase were pH 8.0 and 50°C, respectively. Of the various alcohols tested, xylitol was the most rapidly oxidized, with sorbitol and ribitol being reduced at 65% and 58% of the xylitol rate. The enzyme was completely inactive on arabitol, xylose, glucose, glycerol, and ethanol. The enzyme's xylitol oxidation favored the use of NAD+ (7.9 U/mg) over NADP+ (0.2 U/mg) as electron acceptor, while the reverse reaction, D-xylulose reduction, favored NADPH (7.7 U/mg) over NADH (0.2 U/mg) as electron donor. The Km values for xylitol and NAD+ were 49.8 mM and 38.2 µM, respectively. For the generation of the xylitol biosensor, the above xylitol dehydrogenase and a diaphorase were immobilized on bromocyan-activated sephallose. The gel was then attached on a dissolved oxygen electrode. In the presence of vitamin K3, NAD+ and phosphate buffer, the biosensor recorded a linear response to xylitol concentration up to 3 mM. The reaction was stable after 15 min. When the biosensor was applied to a flow injection system, optimal operation pH and temperature were 8.0 and 30°C, respectively. The strengths and limitations of the xylitol biosensor are its high affinity for NAD+, slow reaction time, narrow linear range of detection, and moderate affinity for xylitol.Key words: xylitol, xylitol dehydrogenase, biosensor, Candida tropicalis.

Effects of the Menstrual Cycle on the Performance of Complex Perceptual-Psychomotor Tasks

Efforts in support of providing equal employment opportunities have created a serious interest in factors which may affect the potential aeronautical adaptability of women. The possible effects of the significant physical and hormonal changes associated with the menstrual cycle have been a focal point of considerable coacera. This study assesses an individual's ability to perform complex, perceptual-psychomotor tasks during different phases of the menstrual cycle. Seventeen women served as paid volunteer subjects. All were between 20 and 30 years of age with a mean age of 24 years. Each woman was tested during the premenstruum (3 or 4 days prior to menstrual flow), during the menstrual flow, and during the intermenstrual phase of the cycle. In addition, data were collected on the use of oral contraceptives and on the severity and prevalence of individual menstrual cycle symptomatology as measured by the Menstrual Distress Questionnaire. The perceptual-psychomotor data were used to evaluate the effects of menstrual cycle and oral contraceptives on performance under stress. The data were also used to test Dalton's hypothesis that the lethargy the premenstruum and menstruation is responsible for lowered judgment and slow reaction time which might result in accidents. The results of the study indicated that there were no performance decrements associated with the menstrual cycle or use of oral contraceptives and failed to support Dalton's hypothesis.