Low energy electron attachment to condensed formic acid

Dissociative electron attachment to formic acid in the condensed phase is studied using improved mass spectrometric detection of the negative ion fragments. The desorbed yields are measured as a function of incident electron energy in the range between 3 to 20 eV. Unlike previous work, the formation of the dehydrogenated anion HCOO? is observed and the signal to noise ratio is much higher for all other ions detected, i.e. OH?, O? and H?. Resonant structure seen in all anion yield functions, is attributed to dissociative electron attachment (DEA), whereas above 14 eV nonresonant dipolar dissociation (DD) dominates the desorption yields

Ion-sensing using chemically-modified ISFETs

Synthetic macrocyclic polyether ion receptors are the active components for the selective and sensitive detection of potassium ions in chemical sensors based on modified ISFETs.\ud \ud Covalent chemical anchoring of the sensing membrane to the gate oxide of the ISFET is essential in order to increase the lifetime of the sensor system to more than three months

Catalyst system based on polymer compounds comprising silasesquioxane-metal complexes

Catalyst systems based on a polymer compound having a molecular weight Mn of greater than 1000 g/mol, and comprising at least one silasesquioxane-metal complex, especially useful for the oxidation and oximation of organic compounds using peroxides; processes for preparation of such catalytic systems; and processes for use of such catalytic systems

The Involvement of Angiotensin Type 1 and Type 2 Receptors in Estrogen-Induced Cell Proliferation and Vascular Endothelial Growth Factor Expression in the Rat Anterior Pituitary

The aim of our study was to examine the involvement of renin-angiotensin system (RAS) in estrogen-induced lactotropes proliferation and vascular endothelial growth factor (VEGF) expression in rat pituitary. The study was performed on Fisher 344 rats underwent 8-day treatment with diethylstilboestrol (DES). The proliferation index (PCNA) and VEGF expression in pituitary sections were estimated using immunohistochemical methods. Treatment with DES increased the number of PCNA-positive cells, VEGF-positive cells, and VEGF-positive blood vessels in pituitary. Stimulatory effect of estrogen on cell proliferation and VEGF expression in blood vessels was attenuated by losartan, PD123319, and captopril. VEGF immunoreactivity in pituitary cells of DES-treated rats was decreased by AT1 antagonist and not changed by AT2 blocker and ACE inhibitor. Our findings suggest the involvement of RAS in DES-induced cell proliferation and VEGF expression in pituitary. Both the AT1 and AT2 receptors appear to mediate the estrogen-dependent mitogenic and proangiogenic effects in rat pituitary

Oligomeric silasesquioxanes and a process for preparing oligomeric silasesquioxanes

Oligomeric silasesquioxanes having the formula R6Si6O9 wherein R is alkyl, cycloalkyl other than cyclohexyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, and/or heteroaryl, and the structure I; processes for preparing oligomeric silasesquioxanes of formula R6Si6O9 wherein R is alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, and/or heteroaryl; processes of using such oligomeric silasesquioxanes; and products obtained thereby

Evidence of Indium impurity band in superconducting (Sn,In)Te thin films

Sn1-xInxTe has been synthesized and studied recently as a candidate topological superconductor. Its superconducting critical temperature increases with Indium concentration. However, the role of Indium in altering the normal state band structure and generating superconductivity is not well-understood. Here, we explore this question in Sn1-xInxTe (0<x<0.3) thin films, characterized by magneto-transport, infrared transmission and photoemission spectroscopy measurement. We show that Indium is forming an impurity band below the valence band edge which pins the Fermi energy and effectively generates electron doping. An enhanced density-of-states due to this impurity band leads to the enhancement of superconducting transition temperature measured in multiple previous studies. The existence of the In impurity band and the role of In as a resonant impurity should be more carefully considered when discussing the topological nature of Sn1-xInxTe

Tumour necrosis factor-alpha polymorphism as one of the complex inherited factors in pemphigus.

The aim of our study was to analyse a significance of tumour necrosis factor (TNF)-alpha promoter gene polymorphisms in relation to the HLA-DR locus in genetic predisposition to pemphigus. TNF-alpha gene polymorphisms in position -238 and -308 were identified using a modified polymerase chain reaction-restriction fragment length polymorphism method in 53 patients with pemphigus (38 with pemphigus vulgaris, 15 with pemphigus foliaceus) and 87 healthy controls. The HLA-DRB1 locus was typed using the polymerase chain reaction SSO method in all the patients and 152 population controls. Carriers of the TNF-alpha polymorphic -308 A allele were found to be more frequent in the pemphigus foliaceus group in comparison with the control group (odds ratio (OR) = 8.12; p = 0.0005). A significant association between HLA-DRB1*04 (OR = 3.86; pcor = 0.0001) and DRB1*14 (OR = 8.4; pcor = 0.0001) and pemphigus vulgaris was found. In this group of patients a decreased frequency of HLA-DRB1*07 (OR = 0.08; pcor = 0.006) was also identified. We have shown for the first time a positive association of TNF-alpha polymorphism in position -308 with pemphigus foliaceus

Structure and singly occupied molecular orbital analysis of anionic tautomers of guanine

Recently we reported the discovery of adiabatically bound anions of guanine which might be involved in the processes of DNA damage by low-energy electrons and in charge transfer through DNA. These anions correspond to some tautomers that have been ignored thus far. They were identified using a hybrid quantum mechanical-combinatorial approach in which an energy-based screening was performed on the library of 499 tautomers with their relative energies calculated with quantum chemistry methods. In the current study we analyze the adiabatically bound anions of guanine in two aspects: 1) the geometries and excess electron distributions are analyzed and compared with anions of the most stable neutrals to identify the sources of stability; 2) the chemical space of guanine tautomers is explored to verify if these new tautomers are contained in a particular subspace of the tautomeric space. The first task involves the development of novel approaches – the quantum chemical data like electron density, orbital and information on its bonding/antibonding character are coded into holograms and analyzed using chemoinformatics techniques. The second task is completed using substructure analysis and clustering techniques performed on molecules represented by 2D fingerprints. The major conclusion is that the high stability of adiabatically bound anions originates from the bonding character of the pi orbital occupied by the excess electron. This compensates for the antibonding character that usually causes significant buckling of the ring. Also the excess electron is more homogenously distributed over both rings than in the case of anions of the most stable neutral species. In terms of 2D substructure, the most stable anionic tautomers generally have additional hydrogen atoms at C8 and/or C2 and they don’t have hydrogen atoms attached to C4, C5 and C6. They also form an “island of stability” in the tautomeric space of guanine