Edge orbits and edge-deleted subgraphs

We prove that for any graphG the edge-deleted subgraphs ofG partition into two isomorphism classes if and only if the edges ofG partition into two orbits under the automorphism group ofG.     

A rapid label-free electrochemical detection and kinetic study of Alzheimer's amyloid beta aggregation

We present the first electrochemical detection, characterization, and kinetic study of the aggregation of Alzheimer's disease (AD) amyloid beta peptides (Abeta-40, Abeta-42) using three different voltammetric techniques at a glassy carbon electrode (GCE). This method is based on detecting changes in the oxidation signal of tyrosine (Tyr) residue. As the peptides aggregate, there are structure conformational changes, which affect the degree of exposure of Tyr to the molecular surface of the peptides. The results show significant differences in the aggregation process between the two peptides, and these correlate highly with established techniques. The method is rapid and label-free, and the principle can be universally applied to other protein aggregation studies related to diseases, such as Huntington's, Parkinson's, and Creutzfeldt Jacob (CJD). This method could also be explored in screening for the effectiveness of AD therapies.     

Construction of asymmetric cell-sized lipid vesicles from lipid-coated water-in-oil microdroplets

We present a simple, rapid, and robust method for preparing asymmetric cell-sized lipid bilayer vesicles using water-in-oil (W/O) microdroplets transferred through an oil-water interface. The efficiency for producing cell-sized model membranes is elucidated in relation to the vesicular size and the weight of contained water-soluble molecules. We demonstrate the biological asymmetric nature and the formation of lipid raft microdomain structures using fluorescence microscopy.     

Synthesis and characterization of cruciform-conjugated molecules based on tetrathiafulvalene

Stepwise acetylenic scaffolding provides cruciform-conjugated molecules with vertically disposed pi-systems, one being an extended tetrathiafulvene (TTF) unit. Two synthetic routes for a cruciform dimer incorporating a total of two extended TTFs was developed, employing either an oxidative Hay coupling reaction as the final dimerization step or as one of the initial steps. Both routes take advantage of ready access to new mono- and diethynylbenzene building blocks incorporating a variety of other functionalitites. The redox and optical properties of the cruciform molecules were investigated by cyclic and differential pulse voltammetries and UV-vis absorption spectroscopy. The access to multiple redox states renders the molecules attractive candidates as wires, or possibly transistors, for molecular electronics. Generation of a quinoid structure by oxidation is supported by density functional theory calculations.     

Modified screen printed electrode for development of a highly sensitive label-free impedimetric immunosensor to detect amyloid beta peptides

Alzheimer's disease (AD) is a fatal neurodegenerative disease affecting approximately 26 million people world-wide, and the number is increasing as life expectancy increases. Since the only reliable diagnosis for the pathology is histochemical post-mortem examination, there is a rather urgent need for reliable, sensitive and quick detection techniques. Amyloid beta, being one of the established and widely accepted biomarkers of AD is a target biomolecule.     

Energetics of cyclohexene adsorption and reaction on Pt(111) by low-temperature microcalorimetry

The heat of adsorption and sticking probability of cyclohexene on Pt(111) were measured as a function of coverage using single-crystal adsorption calorimetry in the temperature range from 100 to 300 K. At 100 K, cyclohexene adsorbs as intact di-sigma bonded cyclohexene on Pt(111), and the heat of adsorption is well described by a second-order polynomial (130 - 47 theta - 1250 theta(2)) kJ/mol, yielding a standard enthalpy of formation of di-sigma bonded cyclohexene on Pt(111) at low coverages of -135 kJ/mol and a C-Pt sigma bond strength of 205 kJ/mol. At 281 K, cyclohexene dehydrogenates upon adsorption, forming adsorbed 2-cyclohexenyl (c-C6H(9,a)) and adsorbed hydrogen, and the heat of adsorption is well described by another second-order polynomial (174 - 700 theta + 761 theta(2)) kJ/mol. This yields a standard enthalpy of formation of adsorbed 2-cyclohexenyl on Pt(111) at a low coverage of -143 kJ/mol. At coverages below 0.10 ML, the sticking probability of cyclohexene on Pt(111) is close to unity (>0.95), independent of temperature.     

Odd factors of a graph

LetG be a graph and letf be a function defined on V(G) such that f(x) is a positive odd integer for everyx ? V(G). A spanning subgraphF ofG is called a [l,f]-odd factor of G if d_F(x) ? {1,3,2026, f(x)} for every x ?V(G), whered _F (x) denotes the degree of x inF. We discuss several conditions for a graphG to have a [1,f]-odd factor.     

Clinical aspects of altered glycosylation of glycoproteins in cancer

Alteration of the expression of carbohydrate structures is frequently observed in tumor cells. This review summarizes the different changes of O- and N-linked glycoproteins observed in cancer cells, the impact of the tumor-related carbohydrate phenotypes on the clinical outcome of the cancer disease, and the various ways in which carbohydrate structures can interact with different carbohydrate-detecting adhesion molecules, selectins, and sialoadhesins. Various ways of inhibiting the formation of cell adhesion-engaged carbohydrates on the cell surface, or inhibiting the binding are discussed. Carbohydrate structures which are in clinical use as circulating tumor markers and the effect of genotypes on tumor marker concentrations are reviewed.