Exciton energies of wurtzite CdS nanoparticles Bautista-Hernández, A; Loaiza-González, G; Meza-Montes, L ...
Solar energy materials and solar cells,
09/2003, Letnik:
79, Številka:
4
Journal Article
Recenzirano
We have determined exciton energies for wurtzite CdS nanoparticles, both theoretically and experimentally. The empirical pseudopotential method has been used to calculate the bulk band structure. The ...discretization of reciprocal space was considered to get the energy gap and the corresponding exciton energy as a function of the nanoparticles size. The CdS nanoparticles were prepared by colloidal methods and the exciton energies were determined from optical absorption measurements. A good agreement between the calculated and the experimental exciton energies is obtained when an average over the experimental size distribution of the nanoparticles is included in the calculation.
Digital staining can be considered as a special form of image enhancement wherein the concern is not only to increase the contrast between the background objects and objects of interest, but to also ...impart the colors that mark the objects' unique reactions to a specific stain. In this paper, we extended the previously proposed multispectral enhancement methods such that the colors of the background pixels can also be changed.
In the previous multispectral enhancement methods a shifting factor is provided to the original spectrum. To implement digital staining, a spectral transformation process is introduced prior to spectral shifting.
The enhancement method is applied to multispectral images of H&E stained liver tissue. The resulting digitally stained images show good correlation with the serial-section images of the tissue which are physically stained with Masson's trichrome.
We have presented a multispectral enhancement method that can be adjusted to produce digitally stained-images. The current experimental results show the viability of the method. However, to achieve robust enhancement performance issues that arise from variations in staining conditions has to be addressed as well. This would be part of our future work.
To study the relationship between the primary sensitization to wasp venoms and the geographical and seasonal circumstances of the anaphylaxis-induced sting.
We performed a retrospective review of 115 ...patients (age 10-80) who suffered a systemic reaction to a wasp sting. Season and type of locality (urban or rural) at the moment of the sting were recorded. Serum specific IgE levels to venoms from
Vespula and
Polistes were measured, and a primary sensitization was determined to whichever genus of wasp for which the highest class of specific IgE was observed. The primary sensitization in relation to the type of locality and the season was assessed using the chi-square test.
Most reactions occurred in urban areas (67.8 %), and in the summer season (63.4 %). Most patients were sensitized to
Vespula venom (94.8 %). Primary sensitization was to
Vespula in 56.5 %, to
Polistes in 10.4%, and undetermined in 33 %. The distribution of geographical areas did not show significant differences in relation to primary sensitization (p > 0.05). Most patients with primary sensitization to
Vespula suffered the anaphylaxis-induced sting after the spring season, with a statistically significant result (p < 0.05).
In our population, the probability of
Vespula sting is higher than
Polistes sting when the reaction occurs after spring. This finding can help us to identify the responsible vespid when the diagnostic tests do not provide an accurate result.
Aims.
Our recent reanalysis of the solar photospheric spectra with non-local thermodynamic equilibrium (non-LTE) models resulted in higher metal abundances compared to previous works. When applying ...the new chemical abundances to standard solar model calculations, the new composition resolves the long-standing discrepancies with independent constraints on the solar structure from helioseismology.
Methods.
Critical to the determination of chemical abundances is the accuracy of the atomic data, especially the
f
values, used in the radiative transfer models. Here we describe, in detail, the calculations of
f
values for neutral oxygen and nitrogen used in our non-LTE models.
Results.
Our calculations of
f
values are based on a multi-method, multi-code approach and they are the most detailed and extensive of its kind for the spectral lines of interest. We also report in this paper the details of an extensive R-matrix calculation of photoionization cross sections for oxygen.
Conclusions.
Our calculation resulted in reliable
f
values with well-constrained uncertainties. We compare our results with previous theoretical and experimental determinations of atomic data. We also quantify the influence of adopted photoionization cross sections on the spectroscopic estimate of the solar O abundance, using data from different sources. We confirm that our 3D non-LTE value is robust and unaffected by the choice of photoionization data, contrary to the recent claim made by Nahar.
Visual impairment and blindness have a significant effect on the socioeconomic development of people and society. The current state of blindness worldwide is 0.7% with a minimum of 7 million ...individuals are becoming blind annually and increasing by 1-2 million each year. About 90% of the world’s blind and visually impaired (BVI) live in developing countries, making their education very difficult. Traditionally, Mathematics has been inaccessible to BVI because its content is rich with visually presented concepts and information.
A simple method is described to monitor the superoxide dismutase (SOD)-inhibitable production of superoxide anion (O2-.) in the liver. The isolated rat liver was perfused in situ with ferricytochrome ...c, and the reduction of this substrate during perfusion was determined. Within 30 s after the introduction of the substrate, significant reduction of ferricytochrome c was observed and stabilized at 2-4 min. A marked reduction of the substrate was observed in the livers of rats that received Escherichia coli lipopolysaccharide (LPS, 1 mg/kg) in vivo 3 h before liver perfusion. Ferricytochrome c reduction was inhibited by SOD, but not significantly with allopurinol or deferoxamine mesylate in the livers of LPS-treated rats. Control livers exhibited only a small reduction of the substrate, and this was not significantly inhibited by SOD. After in vivo LPS administration, O2-. production peaked in the liver at 3 h (6.6 nmol/min) and returned toward normal at 6 h (1 nmol/min) after endotoxin. The amount of O2-. generated by the endotoxic livers was dose related. At 3 h post-LPS, neutrophil infiltration and necrotic areas were found in the histological sections of the liver with concomitant elevation of serum aminotransferases, indicating hepatic abnormalities during the early stage of endotoxemia. Phorbol myristate acetate in the perfusion system markedly enhanced O2-. generation in the endotoxic liver. These results show that the perfused rat liver can be used to measure O2-. generation following in vivo stimuli. The data also demonstrate that O2-. release after LPS treatment in vivo is a short and early event and may have an important role in hepatic injury in endotoxemic conditions.
Increased complexity of computer architectures, consideration of power constraints, and expected failure rates of hardware components make the design and analysis of energy-efficient fault-tolerance ...schemes an increasingly challenging and important task. We develop run-time and study FTI, a multilevel checkpoint library, on an IBM Blue Gene/Q. We show that FTI has a low energy footprint and that, consequently optimal checkpoint-interval values with respect to time and energy are similar.
Despite their unproven efficacy and safety concerns, complementary and alternative therapies (CAT) are used by a high proportion of patients with systemic lupus erythematosus (SLE). A prospective ...survey of past and present CAT use was done on 192 patients (36.5 ± 12.7 years; 106 ± 85 months of disease duration; 94% women) with an SLE diagnosis according to ACR criteria. Quality of life Short Form 36 (SF-36) and cumulated damage (SLICC/ACR) were compared between CAT users and non-users. In all, 103 (53.6%; 95% CI: 46.8–60.9) patients were CAT users (median: two remedies/patient): two (1%) in the alternative mode (CAT instead of allopathic treatment); 101 (52.6%) in the complementary mode (CAT in addition to allopathic treatment). A univariate analysis showed CAT users to have higher cumulated damage (P = 0.01) levels, as well as lower physical function (P = 0.05), social function (P = 0.05) and bodily pain (P = 0.02) domain scores in the SF-36 survey. After adjustment for disease duration with a linear model, only differences in bodily pain (P = 0.04) and cumulated damage (P = 0.05) remained statistically significant. CAT use is apparently associated with lower health status in patients with SLE from Yucatan, Mexico. Because the study was cross-sectional, more research is needed to define the directionality of this association.
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