Sharpening our axes [systems engineering application]

To improve a company's 'chopping' power it is necessary to apply systems engineering principles to 'project systems' and take the time to plan effectively, to reflect upon what it is that is being done and thereby improve the way things are done. This article takes a systems view of the project and applies systems engineering principles to project management. Projects (complex systems) are needed to create deliverables (which are also complex systems) and investing in the former will be more than paid back in the latter. It is our aim here to clear up some misunderstandings about systems engineering and its role within a complex project and to highlight the need for businesses to take time to improve their processes in the context of good systems engineering practice.     

天然气在线分析的准确性和一致性

对基于气相色谱技术的天然气在线分析的准确性和一致性进行了详细和系统的分析与研究。由于气相色谱技术是一种对比技术,因此标定气、分析仪的性能以及标定气的组分成为保障天然气在线分析正确性和一致性的关键因素。该文详细阐述了重力混合制备标定气的步骤,特别是EffecTech方法。同时,研究了分析仪的性能对于天然气在线分析的影响。具体而言,对偏误差与不确定度的分析进行了系统的阐述和详细的分析。通常偏误差和不确定度不可能以一种令人满意的方式结合。然而,目前普遍的做法是在不改变物理性质的前提下,接受组分含量测定所产生的误差。     

A new yeast artificial chromosome vector designed for gene transfer into mammalian cells

The supercritical fluid extraction (SFE) behavior of cocaine and its major metabolite benzoylecgonine (BZE) was investigated and found to be highly dependent upon the chemical nature of the matrix and the manner in which the target drug analytes are incorporated into or on the matrix. The recovery of cocaine from Teflon wool, filter paper, drug-fortified hair, and drug user hair was studied using a variety of CO2/modifier mixtures. Incorporation of a triethylamine (TEA)/water modifier mixture provided dramatic improvements in the recovery of cocaine from interactive matrixes. The results suggest that the SF extractability of cocaine is not limited by analyte solubility; rather, desorption of cocaine from hair binding sites is a rate-limiting step in the SFE process. A displacement SFE mechanism is hypothesized in which TEA (as the triethylammonium cation) competes with cocaine for negatively charged hair binding sites. The dependence of extractability on hair/drug binding interactions allows the differentiation of cocaine present at different discrete sites in hair based on differences in SFE behavior. These findings suggest the potential for distinguishing exogenous (i.e., environmental) from endogenous (i.e., physiological) sources of drugs in hair. In contrast to the results observed for cocaine, SFE recoveries of BZE were poor from all matrixes and under all conditions studied. Its increased polarity, the presence of an additional binding site, and the possibility of multiple charged states suggest that poor BZE recoveries may be due to both poor analyte solubility and failure to desorb the analyte from hair binding sites under the conditions employed.     

The cost-effectiveness of a clinical pharmacist intervention among elderly outpatients

We report the close correlation between changes in serum immunoreactive vascular endothelial growth factor 165 (iVEGF165) levels and metastatic tumor burden measured by computed tomography scan before treatment, during the antitumor response, and during early progression in a patient treated with ex vivo gene therapy for renal cell carcinoma. With the researcher blinded to outcome, iVEGF levels were measured in archived serum samples from a patient with metastatic renal cell carcinoma who demonstrated a 7-month partial remission to treatment with autologous, irradiated human GM-CSF gene transduced tumor vaccine. Although a spontaneous regression could not be formally excluded in this patient, the appearance of 20 new pulmonary metastases on computed tomography scan after nephrectomy and before vaccination indicates that if spontaneous regression occurred, it took place at the start of vaccine treatment.     

Finite element analysis of plates with curved edges

The application of the high precision triangular plate bending element to problems with curved boundaries is considered. Appropriate edge conditions for nodal points on these boundaries are derived. The error inherent in representing the shape of a curved boundary by a series of straight segments is found to be the limiting factor on accuracy, while the effect of approximations in the actual boundary conditions is minor. To overcome the first type of error, the high precision element is modified to include one curved edge. Substantial improvements in accuracy are obtained, as demonstrated in example calculations for circular and elliptical plates.     

The relationship between glycemic control and health-related quality of life in patients with non-insulin-dependent diabetes mellitus

The relationship between glycemic control and health-related quality of life was examined in patients with non-insulin-dependent diabetes mellitus (NIDDM). Within the context of a randomized controlled trial, 275 patients with NIDDM receiving primary care from a Veteran's Administration general medical clinic were enrolled and monitored for 1 year. Glycemic control (glycosylated hemoglobin levels) and health-related quality of life (Medical Outcomes Study Short-Form 36-item Health Survey [SF-36]) were assessed at baseline and at 1 year. Multivariate regression modeling using baseline and change scores during a 1-year period did not find a linear or curvilinear relationship between glycosylated hemoglobin and SF-36 scores (P = .15); this was true even after controlling for five covariates identified a priori (insulin use, number of diabetic complications, duration of diabetes, education, number of hyper-, or hypoglycemic episodes during the preceding month). Health services researchers and clinicians alike need to be aware that these two important outcomes may not be directly related. This lack of association could contribute to the high noncompliance rates observed among patients prescribed complex diabetic regimens. Unless patients perceive a benefit from following such regimens, good glycemic control may continue to be an elusive therapeutic goal, especially in patients with long-standing disease.