U.S. Naval Forces and the Northern Flank of NATO

U.S. policy requires that the Navy have the capability to operate on the northern flank of NATO, specifically in the Norwegian Sea. The vulnerabilities and strengths of both the allied and Soviet positions are discussed in this examination of the balance of power in the area

The Detection of Ionizing Radiation by Plasma Panel Sensors: Cosmic Muons, Ion Beams and Cancer Therapy

The plasma panel sensor is an ionizing photon and particle radiation detector derived from PDP technology with high gain and nanosecond response. Experimental results in detecting cosmic ray muons and beta particles from radioactive sources are described along with applications including high energy and nuclear physics, homeland security and cancer therapeuticsComment: Presented at SID Symposium, June 201

A burst chasing x-ray polarimeter

Gamma-ray bursts are one of the most powerful explosions in the universe and have been detected out to distances of almost 13 billion light years. The exact origin of these energetic explosions is still unknown but the resulting huge release of energy is thought to create a highly relativistic jet of material and a power-law distribution of electrons. There are several theories describing the origin of the prompt GRB emission that currently cannot be distinguished. Measurements of the linear polarization would provide unique and important constraints on the mechanisms thought to drive these powerful explosions. We present the design of a sensitive, and extremely versatile gamma-ray burst polarimeter. The instrument is a photoelectric polarimeter based on a time-projection chamber. The photoelectric time-projection technique combines high sensitivity with broad band-pass and is potentially the most powerful method between 2 and 100 keV where the photoelectric effect is the dominant interaction process. We present measurements of polarized and unpolarized X-rays obtained with a prototype detector and describe the two mission concepts; the Gamma-Ray Burst Polarimeter (GRBP) for the U.S. Naval Academy satellite MidSTAR-2, and the Low Energy Polarimeter (LEP) onboard POET, a broadband polarimetry concept for a small explorer mission

Joint profiling of DNA methylation and chromatin architecture in single cells.

We report a molecular assay, Methyl-HiC, that can simultaneously capture the chromosome conformation and DNA methylome in a cell. Methyl-HiC reveals coordinated DNA methylation status between distal genomic segments that are in spatial proximity in the nucleus, and delineates heterogeneity of both the chromatin architecture and DNA methylome in a mixed population. It enables simultaneous characterization of cell-type-specific chromatin organization and epigenome in complex tissues

Antimony-doped graphene nanoplatelets

Heteroatom doping into the graphitic frameworks have been intensively studied for the development of metal-free electrocatalysts. However, the choice of heteroatoms is limited to non-metallic elements and heteroatom-doped graphitic materials do not satisfy commercial demands in terms of cost and stability. Here we realize doping semimetal antimony (Sb) at the edges of graphene nanoplatelets (GnPs) via a simple mechanochemical reaction between pristine graphite and solid Sb. The covalent bonding of the metalloid Sb with the graphitic carbon is visualized using atomic-resolution transmission electron microscopy. The Sb-doped GnPs display zero loss of electrocatalytic activity for oxygen reduction reaction even after 100,000 cycles. Density functional theory calculations indicate that the multiple oxidation states (Sb3+ and Sb5+) of Sb are responsible for the unusual electrochemical stability. Sb-doped GnPs may provide new insights and practical methods for designing stable carbon-based electrocatalystsclose0

A dynamical model reveals gene co-localizations in nucleus

Co-localization of networks of genes in the nucleus is thought to play an important role in determining gene expression patterns. Based upon experimental data, we built a dynamical model to test whether pure diffusion could account for the observed co-localization of genes within a defined subnuclear region. A simple standard Brownian motion model in two and three dimensions shows that preferential co-localization is possible for co-regulated genes without any direct interaction, and suggests the occurrence may be due to a limitation in the number of available transcription factors. Experimental data of chromatin movements demonstrates that fractional rather than standard Brownian motion is more appropriate to model gene mobilizations, and we tested our dynamical model against recent static experimental data, using a sub-diffusion process by which the genes tend to colocalize more easily. Moreover, in order to compare our model with recently obtained experimental data, we studied the association level between genes and factors, and presented data supporting the validation of this dynamic model. As further applications of our model, we applied it to test against more biological observations. We found that increasing transcription factor number, rather than factory number and nucleus size, might be the reason for decreasing gene co-localization. In the scenario of frequency-or amplitude-modulation of transcription factors, our model predicted that frequency-modulation may increase the co-localization between its targeted genes

Effects of high stimulation current on the induction of ventricular tachycardia

Programmed stimulation at 2 right ventricular sites with 1 to 3 extrastimuli was performed at current strengths of twice diastolic threshold (1.0 +/- 0.2 mA, mean +/- standard deviation) and 10 mA in 41 patients undergoing an electrophysiologic study because of sustained ventricular tachycardia (VT) (11 patients), nonsustained VT (19 patients) or unexplained syncope (11 patients). In 26 patients, VT was not induced by programmed stimulation at twice diastolic threshold. Programmed stimulation at 10 mA induced VT or ventricular fibrillation in 16 of these 26 patients (62%). In 4 of 16 patients, the coupling intervals of the extrastimuli that induced VT/ventricular fibrillation at 10 mA were all equal to or longer than the shortest coupling intervals resulting in ventricular capture at twice diastolic threshold. Fifteen patients had inducible VT at twice diastolic threshold. Programmed stimulation at 10 mA induced a similar VT in 12 of these patients, but resulted in no VT induction in 3 of 15 patients (20%), despite ventricular capture at the same coupling intervals that had induced VT at twice diastolic threshold.This study shows that programmed stimulation at a high current strength may either facilitate or prevent induction of VT. Facilitation of VT induction usually is attributable to a shortening of ventricular refractoriness and the ability of extrastimuli at 10 mA to capture the ventricle at shorter coupling intervals than possible at twice diastolic threshold. However, in 25% of cases, the facilitation of VT induction by 10-mA stimuli is not explained by a shortening of ventricular refractoriness. In these cases, and in the patients in whom 10-mA stimuli prevent the induction of VT that was inducible at twice diastolic threshold, the effects of high current strength appear to be mediated through some other mechanism. Other possible mechanisms include an effect on temporal dispersion of refractoriness or on the pattern or extent of ventricular activation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25627/1/0000177.pd