Morphological survey of the cervicothoracic junctional region

In a randomised clinical study two new microprocessor-controlled tonometers working according to the Mackay-Marg principle (Tono-Pen and ProTon, two samples of each) and two established applanation tonometers [hand-held applanation tonometer, Draeger (HAT) and Goldmann tonometer] were compared with respect to accuracy, precision, examiner dependence and internal measurement differences (Tono-Pen I vs II, ProTon I vs II). The four tonometers were used by two examiners six times on each of 193 eyes of 100 patients of the university eye department. The same measuring procedure was performed on four cadaver eyes in situ, using a manometer system. The correlation coefficient between Tono-Pen and HAT and between ProTon and HAT was 0.9, with a high standard deviation, about +/- 3.1 mmHg. HAT gave the best results in repetitive measurements in the same eye (precision: r = 0.92, SD = +/- 1.41 mmHg). In applanation tonometers but not in Mackay-Marg tonometers measurement values depended significantly on the physician. There was a significantly higher standard deviation between Tono-Pen I and II than between ProTon I and II. Concerning in vitro calibration series on human bulbs (manometry), accuracy was high with each tonometer. The regression line of HAT is similar to that of ProTon. Tono-Pen overestimates the manometrically determined intraocular pressure. Because of their lack of precision the two new tonometers are not suitable for clinical use.     

Gurney Analysis of Porous Shells

There are many application areas, where the ability to accurately predict the speed of expansion of fragments from explosively disseminated porous shells is important. For inert materials this speed in part determines the size of the resulting cloud. For reactive materials this speed in part determines the ability to ignite the material and determines the trade‐off between reactive and inertial fragment effects. Gurney analysis has been used extensively for many years to approximate the speed of fragmenting solid material shells. This work investigates the behavior of HE driven porous shells in spherical and cylindrical geometry and identifies factors to use to multiply solid shell Gurney velocity by to predict the speed of a porous shell.     

SOI power devices

This paper provides an introduction to silicon-on-insulator (SOI) technology and the operating principles of high-voltage SOI devices, reviews the performance of the available SOI switching devices in comparison with standard silicon devices, discusses the reasoning behind the use of SOI technology in power applications and covers the most advanced novel power SOI devices proposed to date. The impact of SOI technology on power integrated circuits (PICs) and the problems associated with the integration of high-voltage and low-voltage CMOS are also analysed     

Atrial natriuretic peptide and oxytocin induce natriuresis by release of cGMP

Our hypothesis is that oxytocin (OT) causes natriuresis by activation of renal NO synthase that releases NO followed by cGMP that mediates the natriuresis. To test this hypothesis, an inhibitor of NO synthase, L-nitroarginine methyl ester (NAME), was injected into male rats. Blockade of NO release by NAME had no effect on natriuresis induced by atrial natriuretic peptide (ANP). This natriuresis presumably is caused by cGMP because ANP also activates guanylyl cyclase, which synthesizes cGMP from GTP. The 18-fold increase in sodium (Na+) excretion induced by OT (1 microgram) was accompanied by an increase in urinary cGMP and preceded by 20 min a 20-fold increase in NO3- excretion. NAME almost completely inhibited OT-induced natriuresis and increased NO3- excretion; however, when the dose of OT was increased 10-fold, a dose that markedly increases plasma ANP concentrations, NAME only partly inhibited the natriuresis. We conclude that the natriuretic action of OT is caused by a dual action: generation of NO leading to increased cGMP and at higher doses release of ANP that also releases cGMP. OT-induced natriuresis is caused mainly by decreased tubular Na+ reabsorption mediated by cGMP. In contrast to ANP that releases cGMP in the renal vessels and the tubules, OT acts on its receptors on NOergic cells demonstrated in the macula densa and proximal tubules to release cGMP that closes Na+ channels. Both ANP- and OT-induced kaliuresis also appear to be mediated by cGMP. We conclude that cGMP mediates natriuresis and kaliuresis induced by both ANP and OT.     

On the Unreacted Hugoniots of Three Plastic Bonded Explosives

There is a continuing interest in determining the detonation characteristics of loaded plastic‐bonded explosives (PBXs). Within the UK, the relevant government agencies wish to better understand the response of insensitive high explosives. This has required more detailed investigation of the transit of reaction from the unreacted state to products. The starting condition for shock to detonation transition (SDT), before application of a kinetic scheme to describe reaction, is thus the unreacted Hugoniot for the material. In this work, three PBXs, manufactured by BAE Land Systems, are investigated and modelled. All contain RDX in differing quantities in an HTPB binder. One of them contains aluminium. Two of the materials have the same weight percentage of filler and binder but differ in the grain size distribution entrained. The experimental Hugoniots are presented, and a composite equation of state is derived using an engineering model, and a model based on continuum mixture theory. Both are shown to describe the measurements well. Further applications of the technique are described and future uses are outlined.     

Vibratory response of diamond-like amorphous carbon cantilevers under different temperatures

Diamond-like amorphous carbon films were deposited using filtered cathodic vacuum arc (FCVA) with the plasma ion immersion implantation (PIII) system. A unique multilayer film, comprising of alternating high-sp³ content (90%), high-stress (9 GPa) films, low-sp³ content (50%), and low-stress films (<0.5 GPa), was fabricated. By alternating these layers, a 1.5-μm-thick film was subsequently deposited. Free-standing microcantilevers measuring 150×50 μm had been subsequently fabricated by using standard lithography and wet etching. The resonance frequency of the microcantilevers was measured by a vacuum laser vibrometer system to be 109.5 kHz. After gradual heating to 240 °C, the resonance frequency was observed to increase to a high of 111.5 kHz.     

Effect of sodium bicarbonate amount on in vitro indomethacin release from self-setting carbonated-apatite cement

We describe our surgical technique of acute pediatric forearm lengthening and joint leveling for treatment of symptomatic forearm-length discrepancies. A retrospective clinical and radiographic analysis was performed of all patients undergoing acute forearm lengthenings of > 1.0 cm between 1983 and 1993. Twenty-four acute forearm lengthenings were reviewed with an average follow-up of 3 years. The diagnosis included osteochondromatosis in 17 patients, growth arrest in four patients, and skeletal dysplasia in three patients. Surgical indications included progressive forearm or wrist deformity, significantly limited or painful forearm rotation, or radial-head subluxation. The average lengthening was 1.5 cm (range, 1.0-2.3), which was 9% of total length (range, 3-20%). The goal for lengthening and wrist-joint leveling was near-neutral ulnar variance and was achieved in all cases. We conclude that the forearm can be lengthened acutely successfully to achieve near-neutral ulnar variance in children with forearm-length discrepancies caused by osteochondromas, growth arrests, or bone dysplasias. The surgical technique and the results are described in 24 forearm lengthenings.     

Large-area low-frequency discharge-produced a-Si:H

Using a capacitive glow discharge process at 380 kHz, very-large-area uniform films of a a-Si:H (60 cm diameter) have been deposited. The thickness uniformity, activated conductivity, photoconductivity and photoinduced effects in these films are discussed.