Robust low loss splicing of hollow core photonic bandgap fiber to itself

Robust, low loss (0.16dB) splicing of hollow core photonic band gap fiber to itself is presented. Modal content is negligibly affected by splicing, enabling penalty-free 40Gbit/s data transmission over > 200m of spliced PBGF

A surface potential study of ion-uptake by 5,11,17,23-tetra-tert-butyl-25,27-diethoxycarbonyl methyleneoxy-26,28,dihydroxycalix[4]arene and 5,17-(3-nitrobenzylideneamino)-11,23-di-tert-butyl-25,27- diethoxycarbonyl methyleneoxy-26,28-dihydroxycalix[4]arene Langmuir Blodgett (LB) monolayers

A study of surface pressure - area (Π-A) isotherms, surface potential (ΔV) and effective dipole moment () of two calix[4] arenes, 5,11,17,23-tetra-tert-butyl-25,27-diethoxycarbonyl methyleneoxy-26,28,dihydroxycalix[4]arene (calixarene I) and 5,17-(3-nitrobenzylideneamino)-11,23-di-tert-butyl-25,27-diethoxycarbonyl methyleneoxy-26,28-dihydroxycalix[4] arene (calixarene II) LB films which have the same lower rim but different upper rim has been carried out. This work used a NIMA Surface Potential (S-POT) sensor attached to an LB trough. Space filling model or Corey, Pauling and Koltun (CPK) precision molecular models have been used to estimate the size and the flexibility of both calix[4]arenes, which has been confirmed by X-Ray analysis in one case. The Π-A-isotherms confirmed that both of the calix[4]arenes form a monolayer film and the orientations of the plane of the calix ring are parallel with the air-water interface. The value of limiting area, (Alim) increases as a result of adding Fe3+ salt in the water subphase. For I, the value increases from 1.28 nm2 to 1.44 nm2 while for II, it increases from 1.70 nm2 to 1.86 nm2. ΔV measurements were performed on a water subphase containing Fe3+ salt in the concentration range 0 – 1.25 10–1 mM. ΔV of the compressed monolayer films increased with increasing Fe3+ concentration indicating the presence of Fe3+ salt bound within the calix[4]arenes. Using the ΔV values, the effective dipole moment has been found using the Helmholtz equation

Applications of Solid Freeform Fabrication at the Naval Research Laboratory

Solid Freeform Fabrication (SFF) and related techniques are used at the Naval Research Laboratory (NRL) for a variety of materials related investigations. Research and applications conducted over the past few years are described including: Helisys Laminated Object Manufacturing System (LOMS) fabrication of: ceramic piezoelectric actuators, tooling for multifunctional materials, and anatomical prototypes for surgical visualization; fabrication of mesoscale electronic and sensor components using a laser forward transfer direct write technique; and visualization of complex, 3-D microstructures using a Stratasys Fused-Deposition Modeler. The paper closes with a brief overview of future SFF related work at the NRL.Support for this work from DARPA, Office of Naval Research, and the Naval Research Laboratory Core Research Program is gratefully acknowledged.Mechanical Engineerin

Metal Surface Energy: Persistent Cancellation of Short-Range Correlation Effects beyond the Random-Phase Approximation

The role that non-local short-range correlation plays at metal surfaces is investigated by analyzing the correlation surface energy into contributions from dynamical density fluctuations of various two-dimensional wave vectors. Although short-range correlation is known to yield considerable correction to the ground-state energy of both uniform and non-uniform systems, short-range correlation effects on intermediate and short-wavelength contributions to the surface formation energy are found to compensate one another. As a result, our calculated surface energies, which are based on a non-local exchange-correlation kernel that provides accurate total energies of a uniform electron gas, are found to be very close to those obtained in the random-phase approximation and support the conclusion that the error introduced by the local-density approximation is small.Comment: 5 pages, 1 figure, to appear in Phys. Rev.

Pulmicort® turbohaler® once daily as initial prophylactic therapy for asthma

AbstractIn a double-blind, randomized, parallel-group clinical trial, 340 asthmatic patients aged 12–70 years received budesonide 400 μg once daily in the morning, budesonide 400 μg once daily in the evening, budesonide 200 μg twice daily or placebo, for 12 weeks in addition to inhaled short-acting β2-agonists used as required (p.r.n.). Budesonide was given as Pulmicort Turbohaler.Peak expiratory flow rate (PEFR) increased by 20 to 30 1 min−1 in each of the active treatment groups, significantly more than in the placebo group (P<0·01). There were no significant differences between the active treatment groups. Symptom improvement and decreased β2-agonist use reflected the PEFR data. Incidences of adverse events in the active treatment groups were similar to those observed in the placebo group.Budesonide 400 μg given once daily morning or evening is equieffective with the same total daily dose given twice daily in the treatment of mild to moderate stable asthmatics

Theory of band gap bowing of disordered substitutional II-VI and III-V semiconductor alloys

For a wide class of technologically relevant compound III-V and II-VI semiconductor materials AC and BC mixed crystals (alloys) of the type A(x)B(1-x)C can be realized. As the electronic properties like the bulk band gap vary continuously with x, any band gap in between that of the pure AC and BC systems can be obtained by choosing the appropriate concentration x, granted that the respective ratio is miscible and thermodynamically stable. In most cases the band gap does not vary linearly with x, but a pronounced bowing behavior as a function of the concentration is observed. In this paper we show that the electronic properties of such A(x)B(1-x)C semiconductors and, in particular, the band gap bowing can well be described and understood starting from empirical tight binding models for the pure AC and BC systems. The electronic properties of the A(x)B(1-x)C system can be described by choosing the tight-binding parameters of the AC or BC system with probabilities x and 1-x, respectively. We demonstrate this by exact diagonalization of finite but large supercells and by means of calculations within the established coherent potential approximation (CPA). We apply this treatment to the II-VI system Cd(x)Zn(1-x)Se, to the III-V system In(x)Ga(1-x)As and to the III-nitride system Ga(x)Al(1-x)N.Comment: 14 pages, 10 figure

DFT calculation of the intermolecular exchange interaction in the magnetic Mn4_4 dimer

The dimeric form of the single-molecule magnet [Mn$_4$O$_3$Cl$_4$(O$_2$CEt)$_3$(py)$_3$]$_2$ recently revealed interesting phenomena: no quantum tunneling at zero field and tunneling before magnetic field reversal. This is attributed to substantial antiferromagnetic exchange interaction between different monomers. The intermolecular exchange interaction, electronic structure and magnetic properties of this molecular magnet are calculated using density-functional theory within generalized-gradient approximation. Calculations are in good agreement with experiment.Comment: 4 page

Prolonged enoxaparin therapy compared with standard-of-care antithrombotic therapy in opiate-treated patients undergoing primary percutaneous coronary intervention

A novel enoxaparin regimen consisting of intra-arterial bolus (0.75 mg/kg) followed by intravenous infusion (0.75 mg/kg/6 hours) has been developed as a possible solution to the delayed absorption of oral P2Y12 inhibitors in opiate-treated ST-elevation myocardial infarction (STEMI) patients undergoing primary angioplasty. We aimed to study the feasibility of this regimen as an alternative to standard-of-care treatment (SOC) with unfractionated heparin ± glycoprotein IIb/IIIa antagonist (GPI). One hundred opiate-treated patients presenting with STEMI and accepted for primary angioplasty were randomized (1:1) to either enoxaparin or SOC. Fifty patients were allocated enoxaparin (median age 61, 40% females) and 49 allocated SOC (median age 62, 22% females). One developed stroke before angiography and was withdrawn. One SOC patient had a gastrointestinal bleed resulting in 1 g drop in hemoglobin and early cessation of GPI infusion. Two enoxaparin patients had transient minor bleeding: one transient gingival bleed and one episode of coffee ground vomit with no hemoglobin drop or hemodynamic instability. Two SOC and no enoxaparin group patients had acute stent thrombosis. These preliminary data support further study of this novel 6-hour enoxaparin regimen in opiate-treated PPCI patients

Speeds and arrival times of solar transients approximated by self-similar expanding circular fronts

The NASA STEREO mission opened up the possibility to forecast the arrival times, speeds and directions of solar transients from outside the Sun-Earth line. In particular, we are interested in predicting potentially geo-effective Interplanetary Coronal Mass Ejections (ICMEs) from observations of density structures at large observation angles from the Sun (with the STEREO Heliospheric Imager instrument). We contribute to this endeavor by deriving analytical formulas concerning a geometric correction for the ICME speed and arrival time for the technique introduced by Davies et al. (2012, ApJ, in press) called Self-Similar Expansion Fitting (SSEF). This model assumes that a circle propagates outward, along a plane specified by a position angle (e.g. the ecliptic), with constant angular half width (lambda). This is an extension to earlier, more simple models: Fixed-Phi-Fitting (lambda = 0 degree) and Harmonic Mean Fitting (lambda = 90 degree). This approach has the advantage that it is possible to assess clearly, in contrast to previous models, if a particular location in the heliosphere, such as a planet or spacecraft, might be expected to be hit by the ICME front. Our correction formulas are especially significant for glancing hits, where small differences in the direction greatly influence the expected speeds (up to 100-200 km/s) and arrival times (up to two days later than the apex). For very wide ICMEs (2 lambda > 120 degree), the geometric correction becomes very similar to the one derived by M\"ostl et al. (2011, ApJ, 741, id. 34) for the Harmonic Mean model. These analytic expressions can also be used for empirical or analytical models to predict the 1 AU arrival time of an ICME by correcting for effects of hits by the flank rather than the apex, if the width and direction of the ICME in a plane are known and a circular geometry of the ICME front is assumed.Comment: 15 pages, 5 figures, accepted for publication in "Solar Physics

Can filesharers be triggered by economic incentives? Results of an experiment

Illegal filesharing on the internet leads to considerable financial losses for artists and copyright owners as well as producers and sellers of music. Thus far, measures to contain this phenomenon have been rather restrictive. However, there are still a considerable number of illegal systems, and users are able to decide quite freely between legal and illegal downloads because the latter are still difficult to sanction. Recent economic approaches account for the improved bargaining position of users. They are based on the idea of revenue-splitting between professional sellers and peers. In order to test such an innovative business model, the study reported in this article carried out an experiment with 100 undergraduate students, forming five small peer-to-peer networks.The networks were confronted with different economic conditions.The results indicate that even experienced filesharers hold favourable attitudes towards revenue-splitting.They seem to be willing to adjust their behaviour to different economic conditions