Reflectance spectra of some fractions of Migei and Murchison SM chondrites in the range of 0.3-2.6 microns

The reddening observed in CM chondrites is not understood. Johnson and Fanale observed that, as CM chondrites are more finely powdered, their spectra become more reddened. In the process of meteorite crushing, the chondrules are broken up. Those authors suggested that in this case the silicate components of the chondrules (mainly olivine), which have higher IR reflectivities, were able to contribute more to the overall spectrum. Gaffey and McCord proposed two possible physical mechanisms which could produce such an effect. But it is also possible that the presence of the organic polymers in the matrix material results in the reddening of the CM spectra. To test these two hypotheses, the matrix material and the material enriched in olivines were separated from Migei and Murchison CM chondrites using a binocular microscope. The spectra of these fractions were compared with the spectra of the bulk samples of Migei and Murchison. The spectra of the most 'clean' Migei matrix fractions indicate that the reddish slopes of CM spectral curves in the near infrared are due to the enhanced olivine feature, rather than to organic matter. The authors propose that the red slope of the spectra of some C-type asteroids may indirectly suggest the presence of olivine in the surface material. At the same time, the red sloped spectra of more distant D-type asteroids seem to be due to the presence of organic materials. If so, then the chemical or physical form of this organic matter must be quite different from the organic materials which would be on the surfaces of the parent bodies of CM chondrites (most likely C-type asteroids). It is also possible that the content of organic components in the CM matrix is too low to change the slope of the spectra

Early stages in the evolution of the atmosphere and climate on the Earth-group planets

The early evolution of the atmospheres and climate of the Earth, Mars and Venus is discussed, based on a concept of common initial conditions and main processes (besides known differences in chemical composition and outgassing rate). It is concluded that: (1) liquid water appeared on the surface of the earth in the first few hundred million years; the average surface temperature was near the melting point for about the first two eons; CO2 was the main component of the atmosphere in the first 100-500 million years; (2) much more temperate outgassing and low solar heating led to the much later appearance of liquid water on the Martian surface, only one to two billion years ago; the Martian era of rivers, relatively dense atmosphere and warm climate ended as a result of irreversible chemical bonding of CO2 by Urey equilibrium processes; (3) a great lack of water in the primordial material of Venus is proposed; liquid water never was present on the surface of the planet, and there was practically no chemical bonding of CO2; the surface temperature was over 600 K four billion years ago

The extended Malkus-Robbins dynamo as a perturbed Lorenz system

Recent investigations of some self-exciting Faraday-disk homopolar dynamo ([1-4]) have yielded the classic Lorenz equations as a special limit when one of the principal bifurcation parameters is zero. In this paper we focus upon one of those models [3] and illustrate what happens to some of the lowest order unstable periodic orbits as this parameter is increased from zero

Comparison of diagnostic informative value of the methods for the determination of direct (hyaluronic acid) and indirect (alanine aminotransferase, aspartate aminotransferase, de Rithis coefficient) of liver fibrosis markers in patients with chronic viral hepatitis C

The results of chronic viral hepatitis C patients examinations are described. A comparative characteristic of the diagnostic informative value of direct (hyaluronic acid) and indirect (alanine aminotransferase, aspartate aminotransferase, de Ritis coefficient) of liver fibrosis markers by the use of ROC - analysis is presented. The objective: to explore the possibility of non-invasive methods for diagnosing liver fibrosis in patients with chronic viral hepatitis C (CVH C). Materials and methods. 66 CVH C with the 1st genotype of the virus were examined. They were either at dispensary observation or ambulatory treatment at Municipal Clinical Hospital №1 (Vinnitsa, Ukraine) and in the clinical department of viral hepatitis at L. V. Gromashevsky Institute of Epidemiology and Infectious Diseases of NAMS (Ukraine). All patients underwent fibroelastography (FEG) on the METAVIR fibrosis score. In all CVH C patients and control group individuals content of hyaluronic acid (HA) in blood serum was determined. ELISA method and “Hyaluronic Acid” kit (Corgenix, Inc., USA) were used. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activity was investigated with kinetic method (analyzer and test system Cobas 6000, Roche Diagnostics, Switzerland). Results: AUC for HA content in serum of CVH C patients was in the range 0.720-0.917 (

The treatment dynamics assessment among patients with chronic viral hepatitis B, infected with human immunodeficiency virus

Introduction: the article represents prospective study results of the treatment dynamics among patients with chronic viral hepatitis B, infected with human immunodeficiency virus. Particularly, the role of qHBsAg dynamics in the serum concerning CHB treatment effectiveness of CHB/HIV coinfected patients as well as clinical and laboratory factors influencing on this marker.The study purpose: To assess treatment dynamics of CHB/HIV coinfected patients basing on quantitative HBsAg determination and other clinical and laboratory test applying. Material and methods: 60 coinfected patients were examined – the main group, 60 CHB monoinfected patients – comparison group to reach established study purpose. Diagnosis of HIV and chronic hepatitis B were verified. A clinical, laboratory, serological, molecular-genetic methods were used. Statistical processing of results was held with applying parametric and nonparametric methods for the data analysis.Research results: There was a slight increase by 1.10 times in serum ALT in “a period of ≤ 6 months of antiviral therapy” with a subsequent decrease by 1.20-1.46 times in “a period of ˃ 6 months of therapy”. There was a decrease in the serum qHBsAg of coinfected patients in accordance with the duration of therapy by 1.56-21.10 times, and in case of the presence of "ALT flare" by 1.31-72.72 times. The greatest decrease in serum qHBsAg by 1.63-42.00 times during HAART was also observed in patients with an initial CD4 + count <350 cells / μl.  A serum qHBsAg was 11.24 times lower after ˃ 12 months of therapy in the group of CHB/HIV coinfected patients with ΔCD4 + ˃100 cells / μl compared with the group of patients with ΔCD4 + 0 - 100 cells / μl.Conclusions: A serum qHBsAg possibly to be decreased by 2 log10 among CHB/HIV coinfected patients after starting HAART with dual activity against HBV and HIV which includes nucleoside reverse transcriptase analogs (Tenofovir Disoproxil Fumarate (TDF) and lamivudine (3TC)). Defined main influencing factors on qHBsAg decreasing included: “ALT flare”, CD4+ count, ΔCD4+ as a result of monofactorial analysis. It is necessary to conduct further multifactorial analysis to determine complex of factors which could influence on further HBsAg by 2 log10 and HBsAg clearance

Photonic Band Gaps of Three-Dimensional Face-Centered Cubic Lattices

We show that the photonic analogue of the Korringa-Kohn-Rostocker method is a viable alternative to the plane-wave method to analyze the spectrum of electromagnetic waves in a three-dimensional periodic dielectric lattice. Firstly, in the case of an fcc lattice of homogeneous dielectric spheres, we reproduce the main features of the spectrum obtained by the plane wave method, namely that for a sufficiently high dielectric contrast a full gap opens in the spectrum between the eights and ninth bands if the dielectric constant $\epsilon_s$ of spheres is lower than the dielectric constant $\epsilon_b$ of the background medium. If $\epsilon_s> \epsilon_b$, no gap is found in the spectrum. The maximal value of the relative band-gap width approaches 14% in the close-packed case and decreases monotonically as the filling fraction decreases. The lowest dielectric contrast $\epsilon_b/\epsilon_s$ for which a full gap opens in the spectrum is determined to be 8.13. Eventually, in the case of an fcc lattice of coated spheres, we demonstrate that a suitable coating can enhance gap widths by as much as 50%.Comment: 19 pages, 6 figs., plain latex - a section on coated spheres, two figures, and a few references adde

Resonance-Induced Effects in Photonic Crystals

For the case of a simple face-centered-cubic photonic crystal of homogeneous dielectric spheres, we examine to what extent single-sphere Mie resonance frequencies are related to band gaps and whether the width of a gap can be enlarged due to nearby resonances. Contrary to some suggestions, no spectacular effects may be expected. When the dielectric constant of the spheres $\epsilon_s$ is greater than the dielectric constant $\epsilon_b$ of the background medium, then for any filling fraction $f$ there exists a critical $\epsilon_c$ above which the lowest lying Mie resonance frequency falls inside the lowest stop gap in the (111) crystal direction, close to its midgap frequency. If $\epsilon_s <\epsilon_b$, the correspondence between Mie resonances and both the (111) stop gap and a full gap does not follow such a regular pattern. If the Mie resonance frequency is close to a gap edge, one can observe a resonance-induced widening of a relative gap width by $\approx 5$.Comment: 14 pages, 3 figs., RevTex. For more info look at http://www.amolf.nl/external/wwwlab/atoms/theory/index.htm

ITPA gene variant may protect against anemia induced during pegylated interferon alfa and ribavirin combination treatment in Ukrainian patients with chronic hepatitis C

The aim of this study was to clarify the association between the inosine triphosphate pyrophosphatase (ITPA) gene variants and PEG-IFNα/RBV combination treatment induced anemia in chronic hepatitis C (CHC) Ukrainian patients. The data were collected from 80 CHC patients with HCV genotype 1 infection. All study participants received standard doses of PEG-IFNα and RBV. According to the Hb level changes patients were distributed into: case group—42 patients with combination treatment induced anemia, and control group—38 patients with no signs of anemia. Genotyping for ITPA gene rs1127354 and rs7270101 variants was performed using PCR followed by RFLP assay. Fisher’s exact test was used to estimate the difference in genotype and allelic distribution. Distribution of rs7270101 genotypes was not significantly different between groups of CHC patients with RBV-induced anemia and without it. The frequency of rs1127354 A allele carriers was significantly higher (P < 0.05) in group of CHC patients without anemia (23.7%) comparing to the group of patients with anemia (7.3%). The respective allele frequency in control group (13.2%) was almost 3-fold higher (P < 0.05) comparing to the case group (4.9%). Significant association of ITPA gene rs1127354 with protection against RBV-induced hemolytic anemia was found in Ukrainian patients with CHC infection. Rs1127354 variant may assist as a pharmacogenetic marker in HCV antiviral therapy correction for side effect avoidance.Целью настоящего исследования было изучить ассоциацию аллельных вариантов гена инозин трифосфат пирофосфатазы (ITPA) с анемией, индуцированной комбинированной терапией пегилированным интерфероном (PEG-IFNα) и рибавирином (RBV) у пациентов из Украины с хроническим гепатитом С (ХГС). Данные собраны у 80 пациентов с ХГС, которые имели первый генотип вируса. Все участники исследования получали стандартные дозы PEG – IFNα и RBV. В соответствии с изменениями уровня гемоглобина пациенты были разделены на исследуемую группу (42 пациента с анемией) и контрольную (38 пациентов без признаков анемии). Ге-нотипирование полиморфных вариантов rs1127354 и rs7270101 гена ITPA проводили с помощью ПЦР с последующим ПДРФ анализом. Распределение генотипов по полиморфному варианту rs7270101 достоверно не отличалось в группе ХГС пациентов с RBV-индуцированной анемией и без нее. Частота носителей аллеля rs1127354 A была выше в группе пациентов c ХГС без анемии (23,7 %) по сравнению с группой пациентов с анемией. Частота соответствующего аллеля в контрольной группе (13,2 %) была выше, чем в группе пациентов с анемией (4,9 %)почти втрое. Найдена достоверная ассоциация полиморфного варианта rs1127354 гена ITPA с протекцией против рибавирин-индуцированной гемолитической анемии у пациентов из Украины с ХГС. Полиморфный вариант rs1127354 может служить фармакогенетическим маркером для коррекции противовирусной терапии гепатита С во избежание побочных эффектов.Метою даного дослідження було вивчити асоціацію алельних варіантів гена інозин трифосфат пірофосфатази (ITPA) з анемією, індукованою комбінованою терапією пегильованим інтерфероном (PEG-IFNα) і рибавірином (RBV) у пацієнтів з України з хронічним гепатитом С (ХГС). Дані були зібрані у 80 пацієнтів з ХГС, які мали 1-ий генотип вірусу. Всі учасники дослідження отримували стандартні дози PEG-IFNα та RBV. Відповідно до змін рівня гемоглобіну, пацієнти були розподілені на: групу дослідження – 42 пацієнти з анемією, індукованою комбінованою терапією, та контрольну групу – 38 пацієнтів без ознак анемії. Генотипування поліморфних варіантів rs1127354 та rs7270101 гена ITPA проводили за допомогою ПЛР з наступним ПДРФ аналізом. З метою оцінки достовірності відмінностей в розподілі генотипів та алелів використовували точний тест Фішера. Розподіл генотипів за поліморфним варіантом rs7270101 достовірно не відрізнявся в групі ХГС пацієнтів з RBV-індукованою анемією та без неї. Частота носіїв алеля rs1127354 A була достовірно вище (P<0,05) в групі ХГС пацієнтів без анемії (23,7%), порівняно з групою пацієнтів з анемією. Частота відповідного алеля в контрольній групі була також достовірно вищою (P<0,05) та перевищувала таку в групі пацієнтів з анемією(4,9%) майже втричі. Було знайдено достовірну асоціацію поліморного варіанта rs1127354 гена ITPA із захистом проти рибавірин-індукованої гемолітичної анемії у пацієнтів з хронічним гепатитом С з України. Поліморфний варіант rs1127354 може слугувати фармакогенетичних маркером для корекції противірусної терапії гепатиту С з метою уникнення побічних ефектів

A simple formula for the L-gap width of a face-centered-cubic photonic crystal

The width $\triangle_L$ of the first Bragg's scattering peak in the (111) direction of a face-centered-cubic lattice of air spheres can be well approximated by a simple formula which only involves the volume averaged $\epsilon$ and $\epsilon^2$ over the lattice unit cell, $\epsilon$ being the (position dependent) dielectric constant of the medium, and the effective dielectric constant $\epsilon_{eff}$ in the long-wavelength limit approximated by Maxwell-Garnett's formula. Apparently, our formula describes the asymptotic behaviour of the absolute gap width $\triangle_L$ for high dielectric contrast $\delta$ exactly. The standard deviation $\sigma$ steadily decreases well below 1% as $\delta$ increases. For example $\sigma< 0.1$ for the sphere filling fraction $f=0.2$ and $\delta\geq 20$. On the interval $\delta\in(1,100)$, our formula still approximates the absolute gap width $\triangle_L$ (the relative gap width $\triangle_L^r$) with a reasonable precision, namely with a standard deviation 3% (4.2%) for low filling fractions up to 6.5% (8%) for the close-packed case. Differences between the case of air spheres in a dielectric and dielectric spheres in air are briefly discussed.Comment: 13 pages, 4 figs., RevTex, two references added. For more info see http://www.amolf.nl/external/wwwlab/atoms/theory/index.htm