Vitamin A status of healthy children in Manisa, Turkey

<p>Abstract</p> <p>Background</p> <p>Vitamin A deficiency is a major public health nutrition problem in the developing world. Even subclinical Vitamin A deficiency is associated with increased childhood mortality. Severe maternal vitamin A deficiency may cause increased mortality in the first months of life. There have been a limited number of studies regarding vitamin A status in Turkey. The aim of this study was to assess vitamin A status of healthy children in Manisa, Turkey.</p> <p>Methods</p> <p>Vitamin A status of 100 healthy children aged 36-48 months is evaluated. The children were seen during routine examination. Serum retinol concentrations were measured by high-performance liquid chromatography. Duration of breast feeding, age solid foods introduced, use of supplementary vitamins, weight and height, and intake of specific groups of nutrients on a daily, weekly and monthly basis were collected from a questionnaire completed by the mothers. Height and weight z-scores were calculated according to national standards. Mothers of 20 of the 100 children were known to have normal serum and breast milk retinol concentrations. Children with normal serum retinol concentration were compared with the children with VAD. Student's t-test and Mann-Whitney test were used to compare independent variables. The Pearson correlation analysis test was used to test relation between numeric variables.</p> <p>Results</p> <p>Mean retinol concentration was 0.98 ± 0.32 μmol/L in the whole study group. Serum retinol concentrations were normal (>0.70 μmol/L) in 89% of the children. When children with normal serum retinol concentrations were compared with those with retinol concentrations lower than 0.70 μmol/L, there was no difference in terms of age, gender, weight and height at the time of study, z-scores, birth weight, birth length, duration of breast feeding, time to begin solid food, rate of supplementary vitamin use, and rate of infections (P > 0.05). There was not any relation between vitamin A concentrations and weight and height at the time of study, z-scores, birth weight, birth length, duration of breast feeding, time to begin solid food, vitamin use, and frequency of intake of specific groups of nutrients (P > 0.05).</p> <p>Conclusions</p> <p>This study showed that VAD is a moderate health problem in Manisa.</p

SiC Substrate effects on electron transport in the epitaxial graphene layer

Hall effect measurements on epitaxial graphene (EG) on SiC substrate have been carried out as a function of temperature. The mobility and concentration of electrons within the two-dimensional electron gas (2DEG) at the EG layers and within the underlying SiC substrate are readily separated and characterized by the simple parallel conduction extraction method (SPCEM). Two electron carriers are identified in the EG/SiC sample: one high-mobility carrier (3493 cm(2)/Vs at 300 K) and one low-mobility carrier (1115 cm(2)/Vs at 300 K). The high mobility carrier can be assigned to the graphene layers. The second carrier has been assigned to the SiC substrate