In many countries the majority of patients with asthma are now treated with inhaled beta 2-agonists as required and regular inhaled steroids. Compliance with asthma medication is poor, particularly for inhaled steroids, which do not give immediate relief of symptoms. An inhaler combining a beta 2-agonist and a steroid may improve compliance and give better control of asthma. We have studied the effect of a fixed combination dry powder inhaler (Turbuhaler) containing terbutaline (250 micrograms) with budesonide (200 micrograms) compared with each drug given alone in a double-blind, crossover study in 74 patients with mild to moderate asthma. This was a multicenter study performed in general practice. After a 1-wk run-in period with placebo inhaler, each treatment was given twice daily for 4 wk in randomized order. Patients measured symptom scores and rescue inhaled beta 2-agonist use and recorded peak expiratory flow (PEF) twice daily. In nine patients recruited to a hospital center, airway responsiveness was measured by the concentration of methacholine required to produce a fall in FEV1 of 20% (PC20) at the end of each treatment period. Of 74 patients randomized, 68 completed all three treatment periods. Their mean age was 37 (18-60) yr and PEF 80 (43-116) % predicted. Combination treatment gave a significant improvement in morning and evening PEF budesonide or terbutaline treatment periods (p < 0.01), and a significant reduction in asthma symptom scores and rescue beta 2-agonist use (p < 0.05). There was a significant patient preference for the combination inhaler.(ABSTRACT TRUNCATED AT 250 WORDS)
Using previously developed and validated finite element (FE) models, an investigation into the behaviour of stainless steel bolted connections has been carried out. Both net section rupture and bearing failure were studied. The main parameters affecting net section rupture were found to be edge distance e 2 and bolt configuration. It was shown that the ductility of stainless steel is sufficient to ensure a failure at the full fracture load (net area multiplied by ultimate tensile strength) for both thick and thin material and hence no reduction factor is required in the design equation. This was confirmed by reliability analysis and a suitable partial safety factor has been derived. The investigation into bearing behaviour showed that the deformation response of stainless steel connections is different from that of carbon steel connections, with stainless steel exhibiting pronounced strain hardening. The locations of fracture initiation obtained from the numerical models match those observed during experimental studies of carbon steel and stainless steel connections. The results of the parametric study were utilised as the basis for the development of design provisions for bearing failure in stainless steel bolted connections, covering both cases in which deformation controls and those for which ultimate strength is the only criterion.
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