Palestinian Conference on Modern Trends in Mathematics and Physics II

Let R be a commutative ring with 1 6= 0 and Nil(R) be its set of nilpotent elements. Recall that a prime ideal of R is called a divided prime if P ½ (x) for every x 2 RnP. The class of rings: H = fR j R is a commutative ring and Nil(R) is a divided prime ideal of Rg has been studied extensively by the speaker(i.e. Badawi). Observe that if R is an integral domain, then R 2 H. Hence H is a much larger class than the class of integral domains. If R 2 H, then R is called a Á-ring.
I wrote the ¯rst paper on Á-rings in 1999 :"Á-pseudo-valuation rings," appeared in Advances in Commutative Ring Theory, 101-110, Lecture Notes Pure Appl. Math. 205, Marcel Dekker, New York/Basel, 1999.

Production and regulation of erythrocytes (red blood cells) is performed through complex processes. Cells are produced in the bone marrow (and the spleen, in mice), where hematopoietic stem cells, that have abilities of self-renewal and differentiation in all blood cell types, allow the appearance of erythroid cells. Throughout successive diviffsions, erythroid progenitors (immature red cells) acquire maturity (via cell markers) to ultimately become mature red blood cells (erythrocytes) that enter the bloodstream in order to carry oxygen to organs and tissues.
This continuous production of erythroid cells is permanently controlled in order to adapt very quickly to changes in or needs of the organism. One of the main feedback controls, discovered in the early 1990's by Koury and Bondurant [3] deals with cell death. Erythroid progenitors die by apoptosis, a programmed cell death (contrary to necrosis). Koury and Bondurant showed that, during an anemia (lack of red blood cells), a growth factor named erythropoietin (Epo) was released by the kidneys and inhibited progenitor apoptosis, allowing a fast production of numerous erythrocytes to get a correct level of red blood cells in blood.
Others controls occur at early stages of erythropoiesis, for instance differentiation of hematopoietic stem cells in cells committed to the red blood cell lineage is partly controlled by Epo. In the presence of Epo, hematopoietic stem cells will preferentially differentiate in red blood cells rather than in white blood cells or platelets.

In this study the interaction of steroid hormones (progesterone and its parent compound cholesterol) with human serum albumin at physiological pH have been studied using UV-VIS spectrophotometer, fluorescence spectrophotometer, and FT-IR spectroscopy. The results showed that UV absorption intensity spectra were increased with the increase of progesterone or cholesterol molar ratios in fixed amount of HSA. From UV spectra the binding constants were obtained and equals (6.354×102M-1)for progesterone and (0.2641×104M-1) for cholesterol. Beside that the results that have been obtained from analysis of fluorescence spectra indicated that progesterone and cholesterol have an ability to quench the intrinsic fluorescence of HSA through a static quenching procedure. The values of Stern-Volmer constant were determined to be (6.26×102 L mol-1) for progesterone- HSA complexes and (6.21×102 L mol-1) for cholesterol- HSA complexes. Also the quenching rate constant values obtained were (6.2×1010 L mol-1s-1) for progesterone and (6.21 × 1010 Lmol-1s-1) for cholesterol.
The binding constant from fluorescence spectrum for progesterone- HSA complexes was found to be (6.56×102 M-1). And for cholesterol- HSA complexes was found to be (0.214 × 104 M-1). It was obviously noted that the obtained values agrees well with the values obtained using UV-VIS spectrophotometer. And that cholesterol binding constant is larger than progesterone binding constant, this refer to the structure of the two compounds which is consistent with that have been reported. FT-IR spectroscopy with Fourier self-deconvolution and second derivative, as well as curve fitting procedures were used in the analysis of amide I, amide II, and amide III regions of HSA to determine protein secondary structure and hormone binding mechanism. It was observed that the intensity of absorption bands decreased as progesterone or cholesterol molar ratios increased. Also all peak positions of the three amide regions were assigned at different progesterone or cholesterol ratios. In addition FT-IR spectra evidence showed that HSA secondary structure has been changed as progesterone or cholesterol molar ratios increased, which was observed in the reduction of α-helices absorption band relative to β-sheets absorption band. The variation in the intensity is related indirectly to the formation of H-bonding in the complex molecules, which accorded for the different intrinsic propensities of α-helix and β-sheets.

In 1960 Overhauser [1] suggested that the ground state of nuclear matter may not be described by plane wave orbitals corresponding to a uniform density fluid phase but rather by orbitals that produce a periodically varying density. Such Overhauser orbitals were shown [2] to give an energy lower than that obtained from plane waves, but only at low densities. Such periodic densities correspond to α particle-like clusters arranged on a lattice and thus correspond to a solid phase. These results were subsequently extended to finite temperature [3] and a triple point of nuclear matter was found at a temperature of about 1.1 MeV. Recent experimental analyses of moderate-temperature nuclear gases produced in heavy ion reactions reveal a large degree of α particle clustering at low densities [4]. The thermodynamic properties and equation of state of low density nuclear matter, including cluster formation, will be examined.

The passage of light through apertures much smaller than the wavelength of the light has proved to be a surprisingly subtle phenomenon. This talk describes how modern developments in nanofabrication, coherent light sources and numerical vector field simulations have led to the upending of early predictions from scalar diffraction theory and classical electrodynamics. Optical response of real materials to incident coherent radiation at petahertz frequencies leads to unexpected consequences for transmission (and extinction) of light through sub wavelength aperture arrays.