578 research outputs found
Silicon-based 2 Terminal Tandem Solar Cells with Lattice-Matched Buffer Layers
A novel structure for a Si-based 2-terminal tandem solar cell was proposed. The structure was optimized to get high efficiency considering the realistic material parameters. Gallium arsenide phosphide (GaAs₁₋xPx) and indium gallium phosphide (In₁₋xGaxP) were suggested as a top-cell material. A semi-empirical method was proposed to calculate the absorption coefficients of GaAs₁₋xPx and In₁₋xGaxP at any value of the composition x. The conversion efficiency of the cell was calculated by simulating its voltage-current characteristics. It was shown that an efficiency of 33.1% can be obtained for a GaAs.₇₃P.₂₇/Si cell and 34.2% for an In.₅₇Ga.₄₃P/Si cell. In₁₋xGaxP was shown to be more promising because of its larger absorption coefficient than GaAs₁₋xPx's
N,N’-Bis(2-chloroethyl)-N-nitrosourea (BCNU)-induced Apoptosis of Neural Progenitor Cells in the Developing Fetal Rat Brain
N,N’-bis(2-chloroethyl)-N-nitrosourea
(BCNU) is one of the major drugs used in chemotherapy against malignant
gliomas due to its effects, such as induction of bifunctional alkylation of
DNA and formation of interstrand DNA cross-linkages, and induces cortical
malformations in the fetal and neonatal rat brain. In this study, pregnant
rats were treated with 7.5 mg/kg of BCNU on gestational day 13 (GD 13), and
their fetuses were collected from 12 to 72 hours after BCNU treatment in
order to examine the timecourses of morphological and immunohistochemical
changes in neural progenitor cells in the developing brain. The number of
pyknotic cells in the telencephalon peaked at 24 h and then gradually
decreased until 72 h. The majority of these pyknotic cells were positive
for cleaved caspase-3, a key executioner of apoptosis. The pyknotic cells
showed the ultrastructural characteristics of apoptosis. The number of
p53-positive cells began to increase prior to the appearance of apoptotic
cells and p21-positive cells. The number of phosphorylated-histone
H3-positive cells (mitotic cells) decreased from 24 to 36 h. The number of
Iba1-positive cells (microglial cells) in the telencephalon increased from
12 to 48 h. These results suggest that BCNU induces p53-dependent apoptosis
and reduces proliferative activity, resulting in reduction of the weight of
the telencephalon and the thickness of the telencephalic wall in the fetal
brain. This study will help to clarify the mechanisms of BCNU-induced fetal
brain toxicity
Ionized bubble number count as a probe of non-Gaussianity
The number count of ionized bubbles on a map of 21 cm fluctuations with the
primordial non-Gaussianity is investigated. The existence of the primordial
non-Gaussianity modifies the reionization process, because the formation of
collapsed objects, which could be the source of reionization photons, is
affected by the primordial non-Gaussianity. In this paper, the abundance of
ionized bubbles is calculated by using a simple analytic model with the local
type of the primordial non-Gaussianity, which is parameterized by f_{NL}. In
order to take into account the dependence of the number count on the size of
ionized bubbles and the resolution of the observation instrument, a threshold
parameter B_b which is related to the the surface brightness temperature
contrast of an ionized bubble is introduced. We show the potential to put the
constraint on f_{NL} from the number count by future observations such as LOFAR
and SKA.Comment: 6 pages and 9 figures, submitted to MNRA
Is There Any Association between TV Viewing and Obesity in Preschool Children in Japan?
Obesity in children is a serious public health problem, and TV viewing is considered a potential risk factor. Since, however, no relevant association studies have been conducted in Japan, we evaluated the association between TV viewing and obesity using a population-based study conducted in a Japanese town. All 616 preschool children in the town were enrolled in February 2008, and a self-administered questionnaire to collect children's and parents' characteristics was sent to the parents. We dichotomized the time spent TV viewing and evaluated associations by logistic regression using a "less than 2h" category as a reference. The questionnaire was collected from 476 participants (77.3%), of whom 449 were available for the final analyses. Among them, 26.9% of preschool children reported 2 or more hours of TV viewing per day and 8.2% were defined as obese. In logistic regression analyses, there was no positive association in unadjusted (odds ratio [OR]1.11, 95% confidence interval [95% CI]:0.50-2.49) or adjusted models for exclusively breastfed status, sleep duration, or maternal factors (OR1.11, 95% CI:0.50-2.51). We also found no positive association between TV viewing and overweight status, possibly owing to the influence of social environment, low statistical power, or misclassification.</p
Impact of Breastfeeding on Body Weight of Preschool Children in a Rural Area of Japan: Population-based Cross-sectional Study
To investigate the effect of exclusive breastfeeding on the likelihood of Japanese preschool children being overweight, population-based cross-sectional survey data from M town in Japan were used. Using the population registry of this town, all 616 preschool children were identified, and a self-administered questionnaire was sent to their parents. The exposure variable of interest was exclusive breastfeeding from birth to 6 months, and the outcome variable of interest was the children being overweight at preschool age. Statistical analyses used included logistic regression and sensitivity analyses. In the final analyses, we included 448 preschool children. Although all point estimates indicated a protective effect, logistic regression analyses showed no significant reduction in being overweight due to exclusive breastfeeding in the unadjusted model (odds ratio (OR)0.70, 95% confidence intervals:0.30-1.64), the model adjusted for birth weight (OR0.70, 95% CI:0.30-1.63), the model adjusted for child lifestyle (OR0.71, 95% CI:0.30-1.67), or the model adjusted for parental factors (OR0.46, 95% CI:0.15-1.37). In sensitivity analyses, point estimates were not significant, but a protective effect was observed. In conclusion, our results suggest that breastfeeding might have a protective effect on Japanese preschool children against being overweight, although statistical significance was not observed due to the limitation of the statistical power of the findings.</p
Monthly minodronate inhibits bone resorption to a greater extent than does monthly risedronate
AbstractAs a bisphosphonate, minodronate (MIN) is one of the strongest inhibitors of bone resorption. However, there have been no reports directly comparing the antiresorptive effects of monthly MIN with those of monthly risedronate (RIS). We enrolled 30 cases of osteoporosis (OP; 16 in the MIN group [mean age: 68.2 years] and 14 in the RIS group [mean age: 68.1 years]) to investigate the early effects of treatment by monthly MIN or RIS over a 4-month period using bone turnover marker values. Only female patients were enrolled to avoid gender bias. Urinary cross-linked N-telopeptide of type I collagen (NTX) before treatment and at 1, 2, and 4 months of therapy, as well as serum bone alkaline phosphatase and alkaline phosphatase before treatment and at 4 months afterwards, were evaluated. All bone turnover marker values were significantly decreased at 4 months in both groups. The changes in urinary NTX at the study end point for RIS and MIN were −30.1% and −63.1%, respectively. From 2 months of treatment, the antiresorptive effects on urinary NTX by MIN were significantly higher than those by RIS, indicating that MIN more immediately and strongly inhibited bone absorption. Thus, monthly MIN seems to suppress bone resorption faster and more strongly than RIS in OP treatment
The Sunyaev-Zel'dovich effect and Faraday rotation contributions of galaxy groups to the CMB angular power spectrum
The S-Z effect and Faraday rotation from halos are examined over a wide mass
range, an including gas condensation and magnetic field evolution.
Contributions to the CMB angular power spectrum are evaluated for galaxy
clusters, galaxy groups and galaxies. Smaller mass halos are found to play a
more important role than massive halos for the B-mode polarisation associated
with the S-Z CMB anisotropies. The B-modes from Faraday rotation dominate the
secondary B-modes caused by gravitational lensing at l > 3000. Measurement of
B-mode polarisation in combination with the S-Z power spectrum can potentially
provide important constraints on intracluster magnetic field and gas evolution
at early epochs.Comment: submitted to MNRA
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