Morphological and kinetics study of PEO/PVC blends

The kinetics of spherulite radial growth and the morphology of the compatible system PEO/PVC have been studied by optical microscopy. The usual spherulite radial growth behaviour has been found for compatible blends with PEO content higher than 70%. For lower composition, distortion of the usual spherulite morphology has been observed; the anomalies have been attributed to partial miscibility of the components.     

Applications of ultrashort pulse propagation in Bragg gratings forwavelength-division multiplexing and code-division multiple access

We discuss theoretical and experimental studies on the propagation of ultrashort pulses through fiber Bragg gratings. We also consider several applications in optical communications to be found by combining ultrashort pulses and fiber Bragg gratings: a multiwavelength source for wavelength-division-multiplexed systems and a means for implementing optical code-division multiple access     

Optical characterization of low-temperature-grown GaAs forultrafast all-optical switching devices

Low-temperature-grown GaAs (LT-GaAs) is a promising material for all-optical switching devices due to its outstanding optical characteristics. In this paper, we outline a simplified model we have developed to describe the dynamics of the carriers in this material. We also report the results of a series of measurements that we have performed to characterize the optical properties of the material. Specifically, we present the first measurements of the two-photon absorption coefficient and the refractive index changes as a function of the growth and annealing temperatures in LT-GaAs. Finally, we show how our model can be used to optimize the material for applications in all-optical switching     

The association between visual incompetence and spinal derangement: an instructive case history

Dotarizine is a new diphenylmethylpiperazine derivative with Ca2+ channel blocking properties and inhibitory effects on 5-HT2A and 5-HT2C receptors. Previous pilot studies in healthy volunteers demonstrated a good tolerability after single and multiple dosing. Dotarizine appeared to be rapidly and extensively metabolized to an active compound (FI-6020). We aimed to study the physiologic, subjective and psychomotor acute effects of oral dotarizine after single dose administration, to evaluate the tolerability and safety after multiple dosing over 2 weeks, and to study the pharmacokinetic parameters and linearity after single and multiple administration. Two different studies were carried out in 2 groups of 8 healthy male volunteers. Oral single doses of dotarizine 50, 100 and 200 mg were administered in a randomized, double-blind, crossover, placebo-controlled trial. Oral doses of 50 mg twice daily were administered in an open trial over 14 days. Drug effect assessments included vital signs, collection of adverse events, ECG and blood and urine safety evaluations, subjective effects, psychomotor performance tasks and blood sampling. Dotarizine and its metabolite were determined by gas chromatography with N-P detector. The results showed a good tolerability of dotarizine after single oral doses as well as multiple oral doses over 14 days. No clinically relevant adverse events were reported during the study. The highest single dose (200 mg) produced a slight increase in sedation-related symptoms as well as a slight impairment in psychomotor performance tasks. Dotarizine and its major metabolite proved linear kinetics at single doses. The administration of oral doses of dotarizine 50 mg b.i.d. reached the steady state after the 7th day of treatment. The pharmacokinetic parameters remained similar from day 7 to day 14. The terminal elimination half-life of dotarizine and its metabolite appeared to be between 7 and 12 h.     

Optical dot gain on newsprint determined with the Lund nuclear microprobe

A technique for measuring optical dot gain, i.e. the relative difference between the actual screen dot and the optically perceived one, is presented. By combining measurements from the non-optical nuclear microprobe with data from image analyzing technique the optical dot gain can be determined. The procedure to reach pixel by pixel correlation on a micrometer scale is discussed. In the newsprint sample studied in this investigation a typical optical dot gain between 15 and 20% was deduced. The variation in the optical dot gain was correlated with other characteristic parameters of the print and newsprint and especially a positive correlation to the mass density of the newsprint was observed.     

Low-temperature interface reaction in aluminium-silicon carbide particulate composites produced by mechanical alloying

An experimental investigation has been carried out on the reaction that takes place between 3 and 20 μm SiC particles and the aluminium alloy 1050 matrix of composite materials prepared by a mechanical alloying process. The work is different from that undertaken by other researchers in that the SiC-Al interface reaction has been studied in the temperature range 853–933 K, i.e., with the matrix initially in the solid state. Differential thermal analysis, X-ray diffraction and scanning electron microscopy all show that the SiC-Al reaction initiates in the solid state at temperatures as low as 883 K. The reaction produces Al4C3 and Si, the latter entering into solid solution in the aluminium matrix. At temperatures exceeding 903 K, the reaction produces a liquid phase and at this stage the speed of the interface reaction increases significantly. The results are discussed in terms of Al-Si-C metastable equilibrium and the kinetics of the reaction. This revised version was published online in November 2006 with corrections to the Cover Date.     

Neutron diffraction studies of the incommensurate modulation structure in SrxBa1-xNb2O6 mixed crystals of various compositions

Using time-of-flight technique between 100 K and 700 K a nearly constant IC modulation parameter is found. It depends only weakly on crystal composition. The intensity of the first-and second-order satellites decreases with temperature and at 700 K it is nearly disappeared. These facts are discussed with a view to the anti-phase domain model.     

From categorial to dimensional diagnosis

The concepts of categorical and dimensional assessment approaches and their specific advantages--and disadvantages are described. A combination of both concepts within the framework of Multiple Assessment of Psychiatric Disturbances is proposed. This includes the different levels of behavioural and emotional disturbances, different assessment methods, the situational specificity of behavioural and emotional disturbances and individually tailored and treatment related assessment procedures. Thereby two phases are distinguished. In the first phase basic procedures of the Multiple Assessment of Psychiatric Disturbances are accomplished, which cover a broad spectrum of behavioural and emotional problems. In the second phase a differentiated picture of the-specific disturbance is assessed by using symptom-specific instruments of the Multiple Assessment of Psychiatric Disturbances. In a case report the diagnostic procedure is explained.