Influence of Encapsulation of Fullerenes on Optical and Thermoelectric Properties of Carbon Nanotubes

The hybrid systems based on the carbon nanotubes (CNT) and fullerenes (nanopipodes) are promising for applications in nanoelectronics. With insignificant variation of the CNT diameter the change of the fullerenes geometry takes place. The periodically located inside fullerenes represent a set of quantum points in the one-dimensional super-lattice. Using the variation of inside fullerenes it is possible to modulate the zone structure of the CNT – fullerene system and to control the electronic and phonon characteristics of nanopipodes. In the work the optical and thermoelectric properties of CNT with encapsulated molecules of C60 fullerene have been investigated. Using the first-principle methods the coefficients of absorption, optical conductivi-ty, thermal conductivity, thermoelectric figure of merit for CNT with fullerenes, periodically lo-cated inside the nanotubes at different distances from each other, have been calculated. It has been shown that with decreasing the distance between fullerenes the optical conductivity of CNT – C60 is suppressed at high frequencies. It has been determined that the conductance of the structures with fullerenes is less than the conductance of a clean tube, and approximately equal for considered distances (12.3 and 19.7 Å) between fullerenes. The CNT thermal conductivity due to the encapsulation of fullerenes considerably (3–4 times) decreases for the considered CNT (8.8) – C60 systems.

Phonon Interaction of Ultrasound Waves in Condensed Media

Based on phonon theory the interaction of high frequency sound (ultrasound and hypersonic) with crystal lattices in solids was estimated. The coefficients of absorption in dielectrics and metals, with respect to temperature and sound frequency, were calculated. Analysis of the calculated dependences allows obtaining of nanomaterials with the set sound conductivity and sound absorption in high frequency range.

Dosing Regimens of Cotrimoxazole (Trimethoprim-Sulfamethoxazole) for Melioidosis

ABSTRACT Melioidosis is an infectious disease with a propensity for relapse, despite prolonged antibiotic eradication therapy for 12 to 20 weeks. A pharmacokinetic (PK) simulation study was performed to determine the optimal dosing of cotrimoxazole (trimethoprim-sulfamethoxazole [TMP-SMX]) used in current eradication regimens in Thailand and Australia. Data for bioavailability, protein binding, and coefficients of absorption and elimination were taken from published literature. Apparent volumes of distribution were correlated with body mass and were estimated separately for Thai and Australian populations. In vitro experiments demonstrated concentration-dependent killing. In Australia, the currently used eradication regimen (320 [TMP]/1,600 [SMX] mg every 12 h [q12h]) was predicted to achieve the PK-pharmacodynamic (PD) target (an area under the concentration-time curve from 0 to 24 h/MIC ratio of >25 for both TMP and SMX) for strains with the MIC90 of Australian strains (≤1/19 mg/liter). In Thailand, the former regimen of 160/800 mg q12h would not be expected to attain the target for strains with an MIC of ≥1/19 mg/liter, but the recently implemented weight-based regimen (<40 kg [body weight], 160/800 mg q12h; 40 to 60 kg, 240/1,200 mg q12h; >60 kg, 320/1,600 mg q12h) would be expected to achieve adequate concentrations for strains with an MIC of ≤1/19 mg/liter. The results were sensitive to the variance of the PK parameters. Prospective PK-PD studies of Asian populations are needed to optimize TMP-SMX dosing in melioidosis.

OPTICAL SPECTRA OF SOME PATHOLOGICAL CONDITIONS OF STOMACH TISSUES

Diffuse reflection spectra, diffuse and collimated transmittance spectra of the mucous tissue of stomach anthrus in norm and at a low-differential form of stomach cancer are measured in 300–800 nm spectrum range. The optical coefficients of absorption (μa), scattering (μs) and anisotropy factor (g) for tissues with pathological changes have been calculated by the three-flux model and diffusion approximation methods. It has been determined that the magnitude of optical parameters grows with the development of malignant processes in stomach tissues which indicates the prevalence of forward light scattering and the increase in Mi scatter contribution to the total scattering coefficient of malignant tissues. It has also been shown that the application of two independent theories as methods of tissues' optical parameters determination (μa,μs,g) gives satisfactorily similar results.

The effects of low levels of dietary phosphorus upon the dry matter intake and metabolism of lambs

The effects of feeding roughage-based diets deficient in phosphorus (P) were investigated in two 20- week experiments in young sheep. In Experiment 1, six-month-old lambs were offered diets containing low concentrations of either calcium (LCa HP) or phosphorus (HCa LP) or both minerals (LCa LP) ad libitum for 20 weeks. In Experiment 2,4-month-old lambs were offered the HCa HP, HCa LP and LCa LP diets ad libitum with a further group pair-fed the HCa HP diet at the same dry matter rate as the lambs offered the LCa LP diet. The semi-synthetic diet, based on barley straw, contained adequate quantities of energy and nitrogen. The major effect of the deficiencies was to reduce the dry matter intakes of the lambs. The lambs offered the LCa HP, HCa LP and LCa LP diets had 15,41 and 40% lower dry matter intakes than the HCa HP lambs in Experiment 1, whilst lambs offered the HCa LP and LCa LP diets consumed 34 and 3 1% less in Experiment 2. The dry matter intakes of the lambs were closely related to their plasma inorganic P concentrations in both experiments. In both experiments, the lambs offered the low P diets had lower dry matter digestibility coefficients than those offered the high P diets. This was considered to be due to changes in caeco-colic rather than rumeno-reticular digestion. There was no difference in liveweight gain of lambs pair-fed on the LCa LP and HCa HP diets. The diets, particularly the low P diets, caused significant changes in plasma Ca and P concentrations and demineralization of the bones as measured by rib biopsy and neutron activation analysis. Lambs offered the low P diets had lower faecal endogenous P losses, but the coefficients of absorption of P were similar. Lambs offered the low P diets had smaller slowly exchangeable-pool sizes and lower rates of recycling and irreversible losses of P.

NMR Imaging in Pediatric Practice

Since before Roentgen's discovery of x-rays, man has been searching for a noninvasive method for assessing the soft tissue organs of the body. For many decades this need has been met by standard x-ray techniques. When x-rays pass through a body, they are absorbed by that body in differing amounts depending upon their density. Because most soft tissues have similar densities, conventional radiography is unable to differentiate overlapping soft tissue structures. In the early 1970s this difficulty was overcome by the development of x-ray computed tomography (CT). This advance in radiodiagnosis utilizes the same principle of measuring different coefficients of absorption, but collects data from many different directions and reconstructs them mathematically to display them as a cross-sectional image.

Studies on Leaf Characteristics of a Cline of Eucalyptus urnigera From Mount Wellington, Tasmania. II. Reflection, Transmission and Absorption of Radiation.

Coefficients of reflection of green and glaucous leaves of Eucalyptus urnigera were, respectively, 26 % and 40% for total radiation and 13% and 30% for visible radiation. Transmission coefficients varied only slightly between leaves differing in glaucousness, being about 24 % and 6% for total and visible radiation respectively. These properties resulted in coefficients of absorption of total radiation varying from 50% for green leaves to 37% for glaucous leaves and of visible radiation from 82% to 66 %. The coefficients for total radiation were measured by means of a hemispherical integrating radiometer and those for radiation over the wave band of 350-1350 nm by means of a spectrophotometer. There was good agreement between the two methods. The differences in these spectral properties between the two leaf types are attributed to diffuse reflection by the wax crystals on the surface of the glaucous leaf.