A geochemical and mineralogical study was performed on lignite samples from the Upper Miocene Kovin deposit, hosting three coal seams. The Kovin lignite is characterized by high moisture content, ...medium to high ash yield, medium to high sulphur content and a relatively low gross and net calorific value. The mineralogical composition, and major and trace element contents were determined by X-ray diffraction, scanning electron microscopy with energy dispersive Xray spectroscopy (SEM-EDS) analyses, and inductively coupled plasma optical emission spectrometry (ICP-OES). The most abundant minerals in all lignite samples from the three coal seams are clays (illite/smectite), silicates (quartz, plagioclase), sulphates (gypsum/anhydrite) and carbonate (calcite). The other iron-rich minerals are sulphides, oxides and hydroxides (pyrite, magnetite, haematite, and limonite). In general, mineral matter in the matrix coal consists of illite/ smectite and quartz, while xylite-rich coals, apart from illite/smectite, have a higher content of sulphates and Fe-oxide/hydroxide minerals. The lignite from the Kovin deposit is enriched in As, Cd, Co, Cr, Cu, Ga, Li, Mn, Mo, Ni, Pb, V, Zn, Gd, Tb, Er and Lu in comparison with the Clarke values for brown coals. The statistical analysis of bulk compositional data shows inorganic affinity for the majority of the major and trace elements and possible association with pyrite, illite/ smectite and calcite.
The influence of environmental pH on the production of tumoricidal free radical nitric oxide (NO) was investigated in mouse fibrosarcoma L929 and rat glioma C6 cell lines. A combination of IFN-γ and ...IL-1 induced a significant NO release and subsequent reduction of cell viability in tumor cell lines. Acidification of cell culture medium reduced tumor cell NO production in a pH-dependent manner. While the inhibitory effect of acidosis on NO production in C6 cells was associated with a further decrease in cell viability, it completely rescued L929 cells from NO-dependent apoptotic and necrotic death. Acidic pH diminished IFN-γ+ IL-1-induced expression of inducible NO synthase (iNOS) mRNA and protein, and abolished the activation of iNOS transcription factor IRF-1 in L929 cells. Moreover, extracellular acidosis significantly impaired cytokine-induced phosphorylation of MAP kinase p44/42 (ERK1/2) and subsequent expression of transcription factor c-Fos in L929 cells. Finally, mild acidosis (pH 6.8) augmented, while severe acidosis (pH 6.0) reduced, IFN-γ-induced iNOS activation/NO release and NO-dependent anticancer activity of rat and mouse macrophages. Taken together, our findings indicate that modulation of macrophage and tumor cell iNOS by an acidic microenvironment might influence the progression of NO-sensitive solid tumors.
A petrological, organic geochemical and geochemical study was performed on coal samples from the Soko Mine, Soko Banja basin, Serbia. Ten coal and two carbonaceous clay samples were collected from ...fresh, working faces in the underground brown coal mine from different parts of the main coal seam. The Lower Miocene, low-rank coal of the Soko Mine is a typical humic coal with huminite concentrations of up to 76.2 vol.%, liptinite less than 14 vol.% and inertinite less than 11 vol.%. Ulminite is the most abundant maceral with variable amounts of densinite and clay minerals. Sporinite and resinite are the most common macerals of the liptinite group. Inertodetrinite is the most abundant maceral of the inertinite group. The mineral-bituminous groundmass identified in some coal samples, and carbonaceous marly clay, indicate sub-aquatic origin and strong bacterial decomposition. The mean random huminite reflectance (ulminite B) for the main coal seam is 0.40
±
0.05% Rr, which is typical for an immature to early mature stage of organic matter.
The extract yields from the coal of the Soko Banja basin ranges from 9413 to 14,096 ppm, in which alkanes constituted 1.0–20.1%, aromatics 1.3–14.7%, asphaltenes 28.1–76.2% and resins 20.2–43.5%. The saturated hydrocarbon fractions included
n-C
15 to
n-C
32, with an odd carbon number that predominate in almost all the samples. The contents of
n-C
27 and
n-C
29 alkanes are extremely high in some samples, as a contribution of epicuticular waxes from higher plants. Acyclic isoprenoid hydrocarbons are minor constituents in the aliphatic fraction, and the pristane/phytane (Pr/Ph) ratio varies between 0.56 and 3.13, which implies anaerobic to oxic conditions during sedimentation. The most abundant diterpanes were abietane, dehydroabietane and 16α(H)-phyllocladane. In samples from the upper part of the coal seam, diterpanes are the dominant constituents of the alkane fraction. Polycyclic alkanes of the triterpane type are important constituents of alkane fractions. The occurrence of ββ- and αβ-type hopanes from C
27 to C
31, but without C
28, is typical for the Soko Banja coals.
The major and trace elements in the coal were analysed using X-ray fluorescence (XRF), and inductively coupled plasma-mass spectrometry (ICP-MS). In comparison with world lignites, using the geometric mean value, the coal from the Soko Banja Basin has a high content of strontium (306.953 mg/kg). Higher values than the world lignites were obtained for Mo (3.614 mg/kg), Ni (8.119 mg/kg), Se (0.884 mg/kg), U (2.642 mg/kg) and W (0.148 mg/kg). Correlation analysis shows inorganic affinity for almost all the major and trace elements, except for S, which has an organic affinity.
In Gao and Huang Z.X. Gao, T.Z Huang, Convergence of AOR method, Appl. Math. Comput. 176 (2006) 134–140 some practical sufficient conditions for the convergence of the AOR (accelerated ...overrelaxation) method for solving linear system
Ax
=
b
, with
A being doubly diagonally dominant matrix, are presented. Using a different approach we will give some improvements in both cases, when the matrix
A is either strictly diagonally dominant (SDD) or doubly diagonally dominant. Using the same simple example as in Gao and Huang (2006), we will illustrate how the new approach can significantly improve convergence area.
The area that causes great attention of economic science is the issue of growth and development. The impact of human resources on economic growth is of great importance. Human capital is the driver ...of the economic growth of any national economy, on the other hand, the state is the driver of education of its population. An important driver of development is education, i.e. investing in the education system, which further drives other macroeconomic variables. Both theory and practice are increasingly dealing with the issue of human capital, as important components and factors of the overall economic development of the national economy. Investments in education result in an increase in economic growth, this increase allows for greater investment in future education. Long-term economic growth determines the standard of living, which directly affects human development. The Human Development Index sublimates several parameters in itself and at the same time shows correlations between the economy, quality of life, and level of education in the country. The paper aims to point out the importance of human capital in economic science and practice through the paradigm of the concept of human development, following the trends of HDI in the Republic of Serbia and the surrounding countries.
It is well-known D. Carlson, T. Markham, Schur complements of diagonally dominant matrices, Czech. Math. J. 29 (104) (1979) 246–251,
1 that the Schur complement of a strictly diagonally dominant ...matrix is strictly diagonally dominant. Also, if a matrix is an
H-matrix, then its Schur complement is an
H-matrix, too J. Liu, Y. Huang, Some properties on Schur complements of
H-matrices and diagonally dominant matrices, Linear Algebra Appl. 389 (2004) 365–380,
8. Recent research showed that the same type of statement holds for some special subclasses of
H-matrices, see, for example, Liu et al. J. Liu, Y. Huang, F. Zhang, The Schur complements of generalized doubly diagonally dominant matrices, Linear Algebra Appl. 378 (2004) 231–244. The aim of this paper is to show that the proof of these results can be significantly simplified by using “scaling” approach as in Zhang et al. F. Zhang et al., The Schur Complement and its Applications, Springer, New York, 2005 and to give another invariance result of this type.
Oxidative stress makes an important contribution to the development of autoimmune diabetes. We therefore tested the possible therapeutic value of two anti-oxidants, butylated hydroxyanisole (BHA) and ...pyrrolidine dithiocarbamate (PDTC), in the animal model of diabetes induced in susceptible DA rats by multiple low doses of streptozotocin (MLD-SZ, 20 mg/kg/day for 5 days). Administration of either BHA, or PDTC (50 mg/kg/day for 7 days), after finishing MLD-SZ injections, attenuated both the development of hyperglycemia and insulitis. Ex vivo analysis revealed that BHA treatment reduced the proliferation of autoreactive lymphocytes and down-regulated their adhesion to endothelium. In addition, BHA markedly attenuated the production of proinflammatory cytokines IL-1
β and TNF-
α by both islets of pancreas and peritoneal macrophages. In parallel, macrophage release of cytotoxic oxygen and nitrogen intermediates superoxide anion (O
2
−) and nitric oxide (NO
), respectively, was significantly inhibited. Finally, BHA treatment reduced intrapancreatic expression of inducible NO synthase (iNOS) and consequent production of NO
by pancreatic islets. Together, these data indicate that antioxidant agents might be a feasible therapeutic tools to interfere with development of autoimmune diabetes at multiple levels, including lymphocyte proliferation and adhesion, as well as the production of proinflammatory and cytotoxic mediators.
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