Arrays for the combinatorial exploration of cell adhesion

A new method for the fabrication of arrays of self-assembled monolayers (SAMs) of alkane thiols (ATs) on gold to combinatorially assay surfaces for cell adhesion is reported. A fluorous SAM, which is both cytophobic and solvophobic, was used as the background between the array features. The resulting solvophobic background permits the application of an assembly after conjugation strategy for fabrication. SAMs containing mixtures of ATs and peptide-terminated ATs were generated. Multiple cell types demonstrated differential and specific binding to these surfaces. Additionally, pluripotent human embryonic stem cells proliferated on surfaces generated by this method.     

Intermediate coupling model description of55Fe and57Fe

The properties of the negative parity states of⁵⁵Fe and⁵⁷Fe are investigated in the framework of the intermediate coupling model. In the model, a neutron or a quasineutron is coupled to anharmonic vibrations of the core. Anharmonicities of the vibrations are estimated through the observed properties of the core. Energy levels, spectroscopic factors and electromagnetic properties have been calculated. The results of the present calculations are also compared with available experimental results and other theoretical results. The model reasonably accounts for many of the properties of the low-lying states.     

Effect of radiative cooling on collapsing charged grains

The effect of the radiative cooling of electrons on the gravitational collapse of cold dust grains with fluctuating electric charge is investigated. We find that the radiative cooling as well as the charge fluctuations, both, enhance the growth rate of the Jeans instability. However, the Jeans length, which is zero for cold grains and nonradiative plasma, becomes finite in the presence of radiative cooling of electrons and is further enhanced due to charge fluctuations of grains resulting in an increased threshold of the spatial scale for the Jeans instability.     

Automatic Structure Determination of Organic Molecules： Principle and Implementation of the LSD Program

The LSD (Logic for Structure Determination) program gener-ates organic molecular structures from 1D and 2D NMR data without resorting to chemical shift databases. Its use in the res-olution of natural product structure determination problems has been already reported in the literature. This paper describes how data and structures are internally represented and pro-cessed by LSD to build solution structures.     

Phage display affords peptides that modulate beta-amyloid aggregation

As the population ages, the need to develop methods to understand and intercept the processes responsible for protein aggregation diseases is becoming more urgent. The aggregation of the protein beta-amyloid (Abeta) has been implicated in Alzheimer's Disease (AD); however, whether the toxic species is a large, insoluble aggregate or some lower order form is not yet known. Agents that can modulate the aggregation state of Abeta could resolve this controversy by facilitating our understanding of the consequences of aggregation and its underlying mechanism. To date, however, ligands that bind to specific forms of Abeta have not been identified. To address this deficiency, we tested whether phage display could yield such ligands by screening libraries against Abeta in two different states: monomeric or highly aggregated. Intriguingly, the peptides selected had different effects on Abeta aggregation. Peptides selected for binding to monomeric Abeta did not perturb aggregation, but those selected using highly aggregated Abeta increase the rate of aggregation drastically. The latter also alter the morphology of the resulting aggregate. The ability of a peptide to promote aggregation correlated with its affinity for the N-terminal 10 residues of Abeta. This result indicates that the mechanism by which the peptides influence aggregation is related to their affinity for the Abeta N-terminus. Thus, the identification of compounds that bind to this Abeta section can afford agents that affect aggregation. Moreover, the data suggest that endogenous ligands that interact with the N-terminal region can influence the propensity of Abeta to form aggregates and the morphology of those that form. Our data highlight the utility of phage display for identifying ligands that bind to target proteins in different states, and they indicate that such agents can be used to perturb protein aggregation.