Note: Proof of principle of a new type of cluster beam source with potential for scale-up

We introduce a new type of cluster beam source based on the assembly of (metal) clusters within a condensed (rare gas) matrix. The "Matrix Assembly Cluster Source" employs an ion beam to enhance collisions between metal atoms in the matrix and to sputter out clusters to form a beam. We demonstrate the formation and deposition of gold and silver nanoclusters with mean size tunable from a few atoms to a few thousand atoms. The cluster flux is equivalent to a current nanoAmp regime but potentially scalable to milliAmps, which would open up a number of interesting experiments and applications.

Modeling type 2 diabetes-like hyperglycemia in C. elegans on a microdevice

Caenorhabditis elegans (C. elegans) has been widely used as a model organism for biomedical research due to its sufficient homology with mammals at the molecular and genomic levels. In this work, we describe a microfluidic assay to model type 2 diabetes-like hyperglycemia in C. elegans to examine several aspects of this disease on a microdevice. The microdevice is characterized by the integration of long-term worm culture, worm immobilization, and precise chemical stimuli in a single device, thus enabling the multi-parameter analysis of individual worms at a single-animal resolution. With this device, the lifespan, oxidative stress responses, and lipid metabolism of individual worms in response to different glucose concentrations were characterized. It was found that the mean lifespan of worms was significantly reduced by as much as 29.0% and 30.8% in worms that were subjected to 100 mM and 200 mM glucose, respectively. The expression of oxidative stress protein gst-4 was increased, and the expression of hsp-70 (heat shock protein) and skn-1 (redox sensitive transcription factor) genes was down-regulated in worms treated with a high level of glucose. Moreover, fat storage was markedly increased in the bodies of VS29 worms (vha-6p::GFP::dgat-2) that were exposed to the high-glucose condition. The established approach is not only suitable for further elucidation of the mechanism of metabolic disorders involved in diabetes and its complications, but also facilitates the evaluation of anti-diabetic drugs in a high-throughput manner.

Protective effects of low molecular weight chondroitin sulfate on amyloid beta (Aβ)-induced damage in vitro and in vivo

In the present study, we investigated the effects of low molecular weight chondroitin sulfate (LMWCS) on amyloid beta (Aβ)-induced neurotoxicity in vitro and in vivo. The in vitro results showed that LMWCS blocked Aβ25-35-induced cell viability loss and apoptosis, decreased intracellular calcium concentration, reactive oxygen species (ROS) levels, the mitochondrial membrane potential (MMP) depolarization, and the protein expression of Caspase-3. During in vivo experiments, LMWCS improved the cognitive impairment induced by Aβ1-40, increased the level of choline acetyltransferase (ChAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and decreased the level of malondialdehyde (MDA) and acetylcholinesterase (AChE) in the mouse brain. Moreover, LMWCS decreased the density of pyramidal cells of CA1 regions, and suppressed the protein expression of Bax/Bcl-2 and Caspase-3, -9 in the hippocampus of mice. In conclusion, LMWCS possessed neuroprotective properties against toxic effects induced by Aβ peptides both in vitro and in vivo, which might be related to anti-apoptotic activity. LMWCS might be a useful preventive and therapeutic compound for Alzheimer's disease.

Pt Diffusion Dynamics for the Formation Cr-Pt Core-Shell Nanoparticles

Layered core-shell bimetallic Cr-Pt nanoparticles were prepared by the formation and later reduction of an intermediate Pt-ion-containing supramolecular complex onto preformed Cr nanoparticles. The resultant nanoparticles were characterized by X-ray diffraction analysis, transmission electron microscopy, X-ray photoelectron spectroscopy, and aberration-corrected scanning transmission electron microscopy. The results are consistent with the presence of Pt diffusion during or after bimetallic nanoparticle formation, which has resulted in a Pt/Cr-alloyed core and shell. We postulate that such Pt diffusion occurs by an electric-field-assisted process according to Cabrera-Mott theory and that it originates from the low work function of the preformed oxygen-defective Cr nanoparticles and the rather large electron affinity of Pt.