Process for producing tris s(n-methylamino) methylsilane

A method of producing tris (N-methylamine) methylsilane is described including the steps of forming and cooling a liquid solution of methylamine in an inert solvent and under an inert atmosphere at a temperature of about -30 C and slowly adding a quantity of methyltricholorosilane while maintaining said temperature. The reaction mixture is then heated for about 60 minutes at a temperature of about 40 C, followed by filtering the solid portion from the liquid portion. The liquid is distilled to remove the solvent, resulting in a high yield of tris (N-methylamine) methylsilane

Preparation of silicon carbide-silicon nitride fibers by the pyrolysis of polycarbosilazane precursors

The development of silicon carbide-silicon nitride fibers (SiC-Si3N4) by the pyrolysis of polycarbosilazane precursors is reviewed. Precursor resin, which was prepared by heating tris(N-methylamino)methylsilane or tris(N-methylamino)phenylsilane to about 520 C, was drawn into fibers from the melt and then made unmeltable by humidity conditioning at 100 C and 95 percent relative humidity. The humidity treated precursor fibers were pyrolyzed to ceramic fibers with good mechanical properties and electrical resistivity. For example, SiC-Si3N4 fibers derived from tris(N-methylamino)methylsilane had a tensile rupture modulus of 29 million psi and electrical resistivity of 6.9 x ten to the 8th power omega-cm, which is ten to the twelfth power times greater than that obtained for graphite fibers

Spike-timing computation properties of a feed-forward neural network model

Brain function is characterized by dynamical interactions among networks of neurons. These interactions are mediated by network topology at many scales ranging from microcircuits to brain areas. Understanding how networks operate can be aided by understanding how the transformation of inputs depends upon network connectivity patterns, e.g. serial and parallel pathways. To tractably determine how single synapses or groups of synapses in such pathways shape transformations, we modeled feed-forward networks of 7-22 neurons in which synaptic strength changed according to a spike-timing dependent plasticity rule. We investigated how activity varied when dynamics were perturbed by an activity-dependent electrical stimulation protocol (spike-triggered stimulation; STS) in networks of different topologies and background input correlations. STS can successfully reorganize functional brain networks in vivo, but with a variability in effectiveness that may derive partially from the underlying network topology. In a simulated network with a single disynaptic pathway driven by uncorrelated background activity, structured spike-timing relationships between polysynaptically connected neurons were not observed. When background activity was correlated or parallel disynaptic pathways were added, however, robust polysynaptic spike timing relationships were observed, and application of STS yielded predictable changes in synaptic strengths and spike-timing relationships. These observations suggest that precise input-related or topologically induced temporal relationships in network activity are necessary for polysynaptic signal propagation. Such constraints for polysynaptic computation suggest potential roles for higher-order topological structure in network organization, such as maintaining polysynaptic correlation in the face of relatively weak synapses

Diabetes Understanding Among Staff Nurses: Examining the Actual Versus Perceived Knowledge in the Acute Care Setting

Diabetes is the fourth leading cause of death world-wide claiming a staggering 3.8 million lives globally each year to related complications (World Health Organization, 2011). Diabetes complications account for 20% of all acute care admissions or 1 in every 5 patients have a diabetes-related condition (American Diabetes Association, 2011). Patient education in the areas of lifestyle modification, healthy eating habits, and proper medication administration is research-supported to clinically decrease the likelihood of acute complications. Bedside, acute care nurses are at the front line of patient education delivery and have the opportunity to determine behavioral stages related to a patient\u27s readiness to change. The primary nurse can furthermore evoke a sense of relationship between the acute complication and the importance of preventative action and maintenance through bridging these knowledge fundamentals. This descriptive study sought to identify knowledge gaps and inconsistencies in the delivery of diabetes self-care education to patients in the acute care setting. The study was conducted using a convenience sampling of acute care nurses surveyed for their perceived versus actual diabetes knowledge using the Diabetes Self-Reporting Tool (DSRT) and the Diabetes Basic Knowledge Tool (DBKT). Although their perceived knowledge was closely relative to their actual knowledge about the disease, extreme gaps in current and accurate knowledge were identified

Effects of seawater and deionized water at 0 to 80 deg C on the flexural properties of a glass/epoxy composite

The effect on the flexural properties of a glass/epoxy composite of immersion in deionized water or seawater at 0, 25, and 80 C for 451 hr was examined. The percent weight gain at 0 and 25 C was low (0.06 to 0.17 percent) and there was no significant change in the flexural properties for these environmental conditions. At 80 C there was a decrease in the flexural strength of 17 and 20 percent in seawater and deionized water, respectively. This is a comparison to control samples exposed to 80 C heat alone. These decreases were found to be nearly reversible once the samples were dried. Optical microscopy did not reveal cracking of the matrix. The flexural modulus was essentially unaffected by exposure to deionized water and seawater at 80 C

Detection of radio frequency magnetic fields using nonlinear magneto-optical rotation

We describe a room-temperature alkali-metal atomic magnetometer for detection of small, high frequency magnetic fields. The magnetometer operates by detecting optical rotation due to the precession of an aligned ground state in the presence of a small oscillating magnetic field. The resonance frequency of the magnetometer can be adjusted to any desired value by tuning the bias magnetic field. We demonstrate a sensitivity of $100\thinspace{\rm pG/\sqrt{Hz}\thinspace(RMS)}$ in a 3.5 cm diameter, paraffin coated cell. Based on detection at the photon shot-noise limit, we project a sensitivity of $20\thinspace{\rm pG/\sqrt{Hz}\thinspace(RMS)}$.Comment: 6 pages, 6 figure

Polarized nuclear target based on parahydrogen induced polarization

We discuss a novel concept of a polarized nuclear target for accelerator fixed-target scattering experiments, which is based on parahydrogen induced polarization (PHIP). One may be able to reach a 33% free-proton polarization in the ethane molecule. The potential advantages of such a target include operation at zero magnetic field, fast ($\sim$100 Hz) polarization reversal, and operation with large intensity of an electron beam.Comment: 16 pages, 2 figure