Nursing care of acute stroke patients after receiving rt-PA therapy. The NINDS rt-PA Stroke Study Group

Treatment with tissue plasminogen activator (rt-PA) for acute stroke requires intensive care of the patient. The risk of thrombolytic therapy and the need for rapid interventions make it clear that the nursing role during this time is crucial. Nurses should be familiar with safe dosage and administration of rt-PA for stroke, which is clearly different than administration of rt-PA for myocardial infarction. Furthermore, thrombolytic stroke treatment must be accompanied by intensive neurological monitoring to observe for complications. Intracerebral hemorrhage is usually accompanied by an acute change in neurological status and vital sign instability. Intensive monitoring of neurologic condition, vital signs, cardiac status and other standard critical care practices must be initiated immediately to optimize patient outcome.     

Spatial soliton-induced guiding by cross-phase modulation

The authors show that spatial solitons are able to induce the stable guiding of a weak probe beam in a homogeneous Kerr-type nonlinear media through cross-phase modulation (XPM). The modes of the induced waveguide are derived from the propagation equation of the probe. Experiments have been performed in Kerr liquid CS₂, with beams of picosecond duration at infrared and visible wavelengths. Stable guiding of a green probe induced by an IR soliton beam has been demonstrated in several different experimental situations. Induced antiguiding and beam splitting are also reported for pump and probe of perpendicular polarizations. All results are in excellent agreement with numerical simulations of the propagation     

9-Benzyladenines: potent and selective cAMP phosphodiesterase inhibitors

A 6-year-old Quarter Horse gelding with acute onset of a grade-4/5 lameness of the left forelimb 21 days after an encounter with a porcupine was examined. Quills had been removed by the referring veterinarian, and the horse had been treated with antibiotics and hydrotherapy for 14 days. The horse was pyretic and had effusion in the digital synovial sheath. Signs of pain were elicited on palpation of the area. A tentative diagnosis of septic tenosynovitis caused by a porcupine quill was made. Exploratory tenoscopy revealed large amounts of fibrin in the sheath and a 1.2-cm quill. Bacteriologic culture of synovial fluid yielded a pure growth of Staphylococcus aureus. The horse improved dramatically after tenoscopic removal of the quill, debridement of fibrin, and lavage to dilute inflammatory mediators and bacteria, debridement of fibrin, discovery and removal of a quill, and complete evaluation of the sheath for prognostic purposes. Tenoscopy can provide a means for direct observation and enhance the ability of clinicians to debride a septic synovial sheath in a minimally invasive manner.     

A mathematical model and numerical estimation of setting stresses in polymer composites molded under hydrostatic pressure

The effect of compression molding (i.e. molding under hydrostatic pressure) on the magnitude and distribution of setting stresses in particle-reinforced polymer composites is investigated using the finite element method. Models based on fairly random arrangements of the reinforcing particles are used, with different particle size gradations, as well as different aggregate-to-resin ratios. An analytical expression of the maximum setting stresses in these composites is introduced. A non-linear constrained optimization technique is used to obtain the mathematical model parameters which aid in a reasonable numerical estimation of the maximum setting stresses in real systems. The numerical results show that externally applied hydrostatic pressure helps diminish some of the local setting stresses. However, this relief becomes insignificant at the interface between aggregate particles and the resin domains where local setting stresses are maximum. This indicates that the practice of compression molding does not have a significant effect in reducing local setting stresses in ordinary polymer concrele systems.     

Fatigue behaviour of a phenolic matrix composite

This paper presents results of a fatigue life investigations carried out in plate specimens of a fibre-glass-reinforced phenolic matrix composite. Tensile and Young's modulus data were obtained at four different testing temperatures (room temperature, 100, 150 and 200 °C). The fatigue S−N data were obtained at room temperature only and for two stress ratio values (R=0 and 0.4). Fatigue and tensile behaviour was assesesed in the composite with the fibres aligned in the longitudinal loading direction. The results were obtained for two values of volume fraction (0.28 and 0.42) and three different glass surface treatments. A detailed comparison of fatigue results is given taking into account several fatigue parameters and also the testing variables. Results of observations of SEM fracture surfaces are also presented.     

Electrical measurement of the junction temperature of an RF powertransistor

An enhanced electrical method is presented for measuring the average junction temperature of an RF bipolar transistor. A two-step procedure, previously developed for DC operation, is extended to include the junction temperature measurement for an RF power transistor in a tuned amplifier circuit. The measurement technique is convenient, since it can be used with normal, packaged devices, and does not require a complex heat flow model or ambient temperature measurements     

Characteristics of mullite prepared from co-precipitated 3Al2O3·2SiO2 powders

Diphasic gels were prepared by a precipitated process from the mixed solutions of colloidal silica and aluminium nitrate. High-purity stoichiometric mullite powders were produced by calcination of the products of these gels, with an exothermic reaction occurring at 1300°C. The chemical and structural evolutions, as a function of thermal treatment, have been characterized by differential thermal analysis, thermogravimetric analysis, X-ray diffraction, infrared spectroscopy, and electron microscopy. The components of the co-precipitated gels react independently with increasing temperature up to the formation of mullite. The composition of mullite also varies with the temperature of thermal treatment. The calcined powders treated by ball-milling could be sintered into a high-density body, in spite of the occurrence of a small amount of glassy phase during sintering.     

Control teaching via low cost setups

In the framework of engineering laboratory education, this correspondence introduces low-cost experiments that are very convenient to illustrate the application of control techniques on true hardware setups. The paper provides the basic schemes of two automatic bridges that can be built from usual laboratory components     

An investigation into the performance and cost effectiveness of thermosyphon solar water heaters

In this paper, the TRNSYS Simulation Program is used to investigate the monthly and annual solar fraction of a Thermosyphon Solar Water Heater and to evaluate its economic viability in terms of its life cycle savings over a conventional water heating system. The results of the simulation indicate that the yearly solar contribution of the system ranges from 63% for a high hot water consumption profile to 89% for a low consumption pattern. The payback period of the system is as low as 3 years when compared to electric water heating systems. As long as the competitor is diesel oil, the payback period increases to 7–9 years, depending on the hot water consumption profile used.