High impact shock testing of fiber-optic components

MIL-S-901 High Impact Shock tests were performed on commercial-grade and ruggedized fiber-optic connectors, splices, and switches. Both single-mode and multimode connectors and splices were tested. Only multimode switches were tested. Transient losses of varying magnitudes and durations were observed. Most components suffered no permanent degradation.     

Uniqueness for weak solutions of a one-dimensional boundary value problem for the Vlasov-Poisson system

The Vlasov-Poisson system models a collisionless plasma. When a boundary condition is included in the problem it is known that singularities can occur but that weak solutions exist globally in time. This article shows that the weak solution is unique for a problem in one dimension with specular reflection at the boundary.     

Noninvasive Assessment of Human Gastric Motor Function

A noninvasive technique to monitor gastric electrical activity (GEA) and mechanical activity as an aid in assessing gastric motor function is presented. The GEA is measured with ordinary ECG electrodes located on the torso in the region above the stomach. The mechanical activity is recorded through an electrical impedance monitoring device. A study of a mathematical model of the electrically active antral part of the stomach in the body revealed that the waveform of the extracorporeally measured signals can be related to the direction of propagation of the GEA. This feature was confirmed experimentally.     

The structure of events triggered by direct photons in π− p, π+ p andpp collisions at 280 GeV/c

The structure of events associated with the production of direct photons in π^? p, π⁺ p andpp reactions of 280 GeV/c has been studied using data from the WA 70 experiment at the CERN SPS. Results are presented on the distributions of the fractional momenta of the colliding partons and on the fragmentation of the recoil jet and a comparison is made with predictions using the structure functions of Duke and Owens in the Lund Monte Carlo with string fragmentation.     

Quick synthesis of lipid-polymer hybrid nanoparticles with low polydispersity using a single-step sonication method

Lipid-polymer hybrid nanoparticle, consisting of a hydrophobic polymeric core and a lipid monolayer shell, represents a new and promising drug delivery platform that has shown controllable particle size and surface functionality, high drug loading yield, sustained drug release profile, and excellent in vitro and in vivo stability. These lipid monolayer-coated polymeric nanoparticles are typically fabricated through a modified nanoprecipitation method, which involves sample heating, vortexing, and solvent evaporation. Herein we report a new and fast method to synthesize lipid-polymer hybrid nanoparticles with controllable and nearly uniform particle size. Using a bath sonication approach, we demonstrate that the whole hybrid nanoparticle synthesis process can be completed in about 5 min compared with a few hours for previous synthesis approaches. The size and polydispersity of the resulting nanoparticles can be readily controlled by tuning the relative concentrations of individual building components. Colloidal stability tests of the synthesized hybrid nanoparticles in PBS buffer and serum show no signs of aggregation over a period of 5 days. The present method improves the production rate of the hybrid nanoparticles by near 20-fold while not compromising the physicochemical properties of the particles. This work may facilitate the bench-to-bedside translation of lipid-polymer hybrid nanoparticles as a robust drug nanocarrier by allowing for fabricating a large amount of these nanoparticles at high production rate.     

Uncertainty of measurement for summed masses: application to controlled substances

Because sentences for drug possession depend on the mass of the seized drug, testing laboratories must often determine the summed mass of numerous items submitted under a single case. One common practice for this purpose is to continue analyzing and weighing samples until a legal threshold is passed, at which point it is important to inform the court whether the summed mass is significantly above the threshold, or only marginally so. This paper develops a means for estimating the uncertainty of the summed mass for the common situation where the readability, d, of the balance dominates the uncertainty. It is seen that for all sample sizes the uncertainty, UM, is given by the remarkable simple expression UM = (d/2) × [N + SQRT(3N)] + N × CCE, where N is the number of items and CCE is the absolute value of the calibration check error. In most instances, this can be further simplified to UM = N × d.     

Modeling of relay helix functional dynamics and feasibility of experimental verification by neutron scattering

Cellular long-range transport involves motor proteins (MPs) (especially, kinesin and myosin) which contain a so-called relay helix. Its motion is of crucial importance to the conversion of chemical energy released in ATP hydrolysis into the coordinated mechanical movement of the entire motor protein. In this paper, we propose two combined nonlinear mechanisms for this particular functional activity and suggest the application of neutron scattering assays to experimentally determine the incoherent dynamic structure factor S(q,ω). We argue that this type of experiment is not only feasible but it could offer significant insights into the mechanism of MP function at a molecular level.