Nonrandom assignment

One drawback to this method is that physicians in the trial may treat all patients similarly, whether they are in the protocol-driven arm or the usual care arm of the smdy. This contamination can be partially overcome by randomizing physicians to the protocol or usual care arms, and can be overcome more completely by randomizing the sites of care (e.g., different hospitals for different arms of the study). However, these options require large numbers of physicians and/or sites of care and, thus, are costly to implement. Moreover, such a strategy may result in nonrandom assignment of patients to treatment arms. 

Data on the effect of calcium antagonists on cardiovascular disease risks in patients with hypertension are available from one moderate-to-large scale randomized, placebo-controlled trial. In the Systolic Hypertension in Europe (Syst-Eur) trial, nitrendipine-based therapy produced an approximate 10/5 mmHg reduction in SBP-DBP in patients with systolic hypertension and a 42% reduction in the risk of stroke. Similar results were observed in two large, nonrandomized, placebo-controlled trials (with alternate treatment assignment), i.e. the Shanghai Trial of Nifedipine in the Elderly and the Systolic Hypertension in China (Syst-China) trial. 

In addition to the experimental results of phase equilibria, the correlation with the widely known GE models was assigned to. It was indicated by many authors that SLE, LLE, and VLE data of ILs can be correlated by Wilson, NRTL, or UNIQUAC models [52,54,64,79,91-101,106,112,131,134]. For the LLE experimental data, the NRTL model is very convenient, especially for the SLE/LLE correlation with the same binary parameters of nonrandom two-liquid equation for mixtures of two components. For the binary systems with alcohols the UNIQUAC equation is more adequate [131]. For simplicity, the IL is treated as a single neutral component in these calculations. The results may be used for prediction in ternary systems or for interpolation purposes. In many systems it is difficult to obtain experimentally the equilibrium curve at very low solubilities of the IL in the solvent. Because this solubility is on the level of mole fraction 10 or 10 , sometimes only... 

Musculoskeletal Bone area and bone mineral content in lumbar spine, hip, and whole body were measured with dual radiograph absorptiometry in 59 children aged 13-15 who had been bom preterm and randomly assigned standard or aluminium-depleted parenteral nutrition solutions during the neonatal period. Those who had been randomly assigned to standard parenteral nutrition solutions had lower lumbar spine bone mineral content, apparently explained by a reduction in bone size. In nonrandomized analyses, children who were exposed as neonates to aluminium above the median (55 micrograms/kg) had lower hip bone mineral content, independent of bone or body size. The authors concluded that neonates who are exposed to parenteral aluminium may have reduced lumbar spine and hip bone mass during adolescence, potential risk factors for later osteoporosis, and hip fracture. 

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