MC1R,Eumelanin and Pheomelanin: Their Role in Determining the Susceptibility to Skin Cancer

Skin pigmentation is due to the accumulation of two types of melanin granules in the keratinocytes. Besides being the most potent blocker of ultraviolet radiation, the role of melanin in photoprotection is complex. This is because one type of melanin called eumelanin is UV absorbent, whereas the other, pheomelanin, is photounstable and may even promote carcinogenesis. Skin hyperpigmentation may be caused by stress or exposure to sunlight, which stimulates the release of α‐melanocyte stimulating hormone (α‐MSH) from damaged keratinocytes. Melanocortin 1 receptor (MC1R) is a key signaling molecule on melanocytes that responds to α‐MSH by inducing expression of enzymes responsible for eumelanin synthesis. Persons with red hair have mutations in the MC1R causing its inactivation; this leads to a paucity of eumelanin production and makes red‐heads more susceptible to skin cancer. Apart from its effects on melanin production, the α‐MSH/MC1R signaling is also a potent anti‐inflammatory pathway and has been shown to promote antimelanoma immunity. This review will focus on the role of MC1R in terms of its regulation of melanogenesis and influence on the immune system with respect to skin cancer susceptibility.     

Thermodynamic,structural and morphological studies on liquid-crystalline blue phases

Abstract

This article describes the progress in experimental studies of liquid-crystalline blue phases during the past 5 years. Additionally, these results are compared critically with the predictions of theories of the blue phases. Areas considered in this review include (i) the thermodynamic stability of the three polymorphic blue phases and the influence of the cholesteric pitch on this; (ii) the phase diagrams of blue phases; (iii) electric field effects on the blue phase structure and stability; (iv) the morphology and growth of liquid single crystals of blue phases; (v) the symmetry and structural properties of the blue phases.     

STABILIZATION OF LIPID BILAYERS ON SURFACES THROUGH CHARGED POLYMERS

ABSTRACT

It is our concept to use a polymer as a hydrophilic cushion to stabilize a lipid bilayer on a solid support. This can be accomplished by using polyacrylamides with disulfides and DMPE anchors as a hydrophilic cushion. These polymers have the additional functionalities to chemisorb on gold surfaces through the disulfides and to bind a lipid bilayer on it through the insertion of the lipid anchors into the lipid bilayer. This paper shows that a polymer with the additional functionality of charged groups increases the attraction of vesicles to form a tethered supported lipid bilayer. By varying the amount of charged groups in the polymer, we are able to control the hydrophilic behavior of the polymer and therefore are able to change the wetting on a surface. This was examined by measuring the contact angles. Using the technique of the surface plasmon spectroscopy, we are able to monitor the process of vesicle fusion on the polymer support.     

Human Neuroepithelial Cells Express NMDA Receptors

L-glutamate, an excitatory neurotransmitter, binds to both ionotropic and metabotropic glutamate receptors. In certain parts of the brain the BBB contains two normally impermeable barriers: 1) cerebral endothelial barrier and 2) cerebral epithelial barrier. Human cerebral endothelial cells express NMDA receptors; however, to date, human cerebral epithelial cells (neuroepithelial cells) have not been shown to express NMDA receptor message or protein. In this study, human hypothalamic sections were examined for NMDA receptors (NMDAR) expression via immunohistochemistry and murine neuroepithelial cell line (V1) were examined for NMDAR via RT-PCR and Western analysis. We found that human cerebral epithelium express protein and cultured mouse neuroepithelial cells express both mRNA and protein for the NMDA receptor. These findings may have important consequences for neuroepithelial responses during excitotoxicity and in disease.     

Normally Distributed Probability Measure on the Metric Space of Norms

In this paper we propose a method to construct probability measures on the space of convex bodies. For this purpose, first, we introduce the notion of thinness of a body. Then we show the existence of a measure with the property that its pushforward by the thinness function is a probability measure of truncated normal distribution. Finally, we improve this method to find a measure satisfying some important properties in geometric measure theory.     

Substituent effects on gas-phase acidities of formic acid and its silicon and sulphur derivatives R − M(= X)XH(M = C., Si; X = O,S; R = H,F, CI,OH, NH2 and CH3)

Ab initio molecular orbital methods at the CBS-Q level of theory have been used to study the effect of substituent (F, Cl, NH₂, OH and CH₃) on the gas-phase acidities of formic acid, HCOOH, its silicon and sulphur derivatives R-M(= X)XH(M = C., Si; X = 0, S; R = F, Cl, OH, NH₂ and CH₃). For formic acid and its thio and dithio derivatives the acidity changes upon substitution are irregular and depend on both the type of substituent, position and degree of replacement of oxygen atoms by sulphur atoms. For sila carboxylic acids and their thio and dithio derivatives the calculated acidities regularly increase in the order: R-SiOOH < R-Si(=S)OH ? R-Si(=O)SH < R-SiSSH(R = H, F, Cl, OH, NH₂ and CH₃). The chloro derivatives are the strongest among the acids studied. The highest gas phase acidity (1277.6 kJmol^?1) has been calculated for ClC(=S)OH.     

Berezinians,Exterior Powers and Recurrent Sequences

We study power expansions of the characteristic function of a linear operator A in a p|q-dimensional superspace V. We show that traces of exterior powers of A satisfy universal recurrence relations of period q. ‘Underlying’ recurrence relations hold in the Grothendieck ring of representations of GL(V). They are expressed by vanishing of certain Hankel determinants of order q+1 in this ring, which generalizes the vanishing of sufficiently high exterior powers of an ordinary vector space. In particular, this allows to express the Berezinian of an operator as a ratio of two polynomial invariants. We analyze the Cayley–Hamilton identity in a superspace. Using the geometric meaning of the Berezinian we also give a simple formulation of the analog of Cramer’s rule Mathematics Subject Classification (2000): 15A15, 58A50, 81R99 To the memory of Felix Alexandrovich Berezin     

Lattice variation and thermal parameters of gel grown KDP crystals added with some ammonium compounds

Pure and impurity added (with NH₄Cl, NH₄NO₃, NH₄H₂PO₄, and (NH₄)₂SO₄) KDP single crystals were grown by the gel method using silica gels. X-ray diffraction data were collected for powder samples and used for the estimation of lattice variation and thermal parameters like Debye-Waller factor, mean-square amplitude of vibration, Debye temperature and Debye frequency. The thermal parameters do not vary in a particular order with respect to impurity concentration. The results obtained are reported and discussed.     

Generalized Random Environment INAR Models of Higher Order

Mediterranean Journal of Mathematics - Let $$C_{\varphi }$$ be the composition operator with monomial symbol $$\varphi (z)=z^m$$ , $$z\in \mathbb {D}$$ , for some positive integer m. In this...