Laser radiation scattering by the optical breakdown plasma

The spatial distribution measurements of laser radiation, scattered in the laser spark, were accomplished for various laser radiation wavelengths (1060, 530, 353, and 265 nm) and various pressures of the gas (air at 10-760 mm Hg). The interference structure of the laser light scattering cone behind the laser spark was observed for the first time. It is proposed to consider the observed structure as a result of interference of the laser radiation, scattered by two or more self-focusing centers in laser spark air plasma. The experimental dependence of the maximal angle of the light scattering on the gas pressure and on the laser radiation wavelength was obtained     

The effect of a split in WAIS-R VIQ and PIQ scores on patients with cognitive impairment and psychiatric illness

To determine the most effective treatment for acrodermatitis chronica atrophicans, several clinical trials were undertaken in recent years to evaluate whether a 2-week course of ceftriaxone would be superior to oral antibiotics. Of the 46 patients suffering from acrodermatitis chronica atrophicans, 14 were treated with ceftriaxone 2g for 15 days. The remaining patients received either oral penicillin V 1.5 million IU t.i.d. or doxycycline 100 mg b.i.d. for 20 to 30 days. Patients were followed up for at least 1 year. Of the 14 ceftriaxone-treated patients four showed incomplete regression of the inflammatory skin changes after 6 to 12 months. Two out of five patients who were monitored for Borrelia burgdorferi DNA excretion were still positive after 12 months as compared to none of six patients who were treated orally for 20-30 days. Six out of 11 patients treated orally for only 20 days needed retreatment after 6 months because of continuing skin manifestations, neuropathy or arthralgia. A 30-day duration of treatment with oral antibiotics and not the chosen antibiotic is crucial for curing acrodermatitis chronica atrophicans. The duration of treatment with ceftriaxone needed for eradication of Borrelia in acrodermatitis chronica atrophicans has yet to be determined in future studies.     

Arthroscopic replacement of the anterior cruciate ligament with a double semitendinosus tendon

At the university hospital of emergency surgery in Innsburck and at the emergency services department of the hospital in Schwaz, anterior cruciate ligament reconstruction was performed in 467 patients between January 1992 and September 1993. In 117 cases, a double semitendinous tendon was used as an autograft. A total of 60 of these patients were followed up at an average of 20 months (13-33) after reconstruction. The results were rated according to the OAK and the Tegner scores. Objective measurements of instability were carried out by a KT 1000 arthrometer. In addition, 21 patients underwent computer-interfaced dynamometer testing using a Cybex 6000. Standardized loading of the thigh muscles was performed at angular velocities of 60 degrees/s (3 repetitions) and 240 degrees/s (30 repetitions): peak torques and total work were analyzed. The mean age was 23.5 years (17-55): 48 were male, 21 female. The main reasons for the ACL ruptures were sports injuries (51 cases). The patients were classified into three groups according to the data of the repair (group 1 reconstruction up to 1 week after trauma-28 patients: group 2: reconstruction between the 2nd and 6th week after trauma-15 patients: group 3: reconstruction 6 and more weeks after trauma-26 patients). In group 1. additional ruptures of the menisci. lesions of the MCL. and chondromalacia were seen in 71.4%. in group 2 in 73.3% and in group 3 in 80.8%. The average rating in the OAK score was 90.16 points: 38 patients (55.70%) had excellent results. 18(26.09%) were good. 9(13.04%) were fair and 4(5.80%) were poor. The Tegner activity score showed a reduction of 0.36 points on average. The largest amount of anterior translation was performed with the KT 1000 manual drawer test (2.29 mm on average compared with the contralateral side). Dynamometer testing showed a statistically significant difference in flexor and extensor mechanism (compared with the non-involved side) in both peak torques and total work. A repeat arthroscopy became necessary in five cases: arthrofibrosis in three and incipient joint infection in two cases.     

Static and dynamic analysis of tunable two-section high-speeddistributed feedback laser utilizing the gain lever effect

Analysis of a novel semiconductor laser structure designed for obtaining wide tuning range along with high speed modulation response is presented. The laser consists of a composite cavity structure with two active (gain) sections. One of the sections has a grating corrugation while the other is flat. A detailed round-trip analysis is combined with the rate equations, which include sublinear gain/carrier relation, to perform steady-state and small-signal analysis. It is shown that the biasing (dc) condition of the different sections plays a critical role in the determination of the dynamic response of the device. In addition, we show that the gain-lever effect can be utilized for a considerable enhancement of the frequency modulation (FM) response. Other critical structural parameters such as the grating coupling coefficient and device geometry are discussed     

Crystallographic shear planes in nanocrystalline SnO2 thin films by high-resolution transmission electron microscopy

Atomic structures of crystallographic shear planes (CSPs) in nanocrystalline thin films of semiconductor SnO₂ were investigated by high-resolution electron microscopy. The films were prepared by electron beam evaporation in high vacuum (10^–6 torr) and followed by annealing in synthetic air at 700 °C for 1–2 H. CSPs with the displacement vector of [1/2 0 1/2] were observed in the planes parallel to (¯101), (110) and (¯3¯21). Most of the CPSs were found to terminate or interact with each other within SnO₂ crystallites. Partial dislocations exist at terminal places of CSPs or along intersecting lines of CSPs. CSP steps were also observed. Structural models of these defects have been proposed. Based on analysis of experimental data, it has been suggested that the Sn/O ratio at CSPs which are not parallel to their displacement vector, at cores of partial dislocations and at CSP steps, is higher than that of the perfect structure, that is, these defects are able to provide extra free electrons with the films.