Is it safe to have a laboratory test?

A recent US Institute of Medicine report indicated that up to 98,000 deaths and more than 1 million injuries occur each year in the United States due to medical errors. These include diagnostic errors, such as an error or delay in diagnosis, failure to employ indicated tests and the use of outmoded tests. Laboratory tests provide up to 80% of the information used by physicians to make important medical decisions, therefore it is important to determine how often laboratory testing mistakes occur, whether they cause patient harm, where they are most likely to occur in the testing process, and how to prevent them from occurring. A review of the literature and a US Quality Institute Conference in 2003 indicates that errors in laboratory medicine occur most often in the pre-analytical and post-analytical steps in the testing process, but most of the quality improvement efforts focus on improving the analytical process. Measures must be developed and employed to reduce the potential for mistakes in laboratory medicine, including better indicators for the quality of laboratory service. Users of laboratory services must be linked with the laboratorys information system to assist them with decisions about test ordering, patient preparation, and test interpretation. Quality assessment efforts need to be expanded beyond external quality assessment programs to encompass the detection of non-analytical mistakes and improving communication between the users of and providers of laboratory services. The actual number of mistakes in laboratory testing is not fully recognized, because no widespread process is in place to either determine how often mistakes occur or to systematically eliminate sources of error. We also tend to focus on mistakes that result in adverse events, not the near misses that cause no observable harm. The users of laboratory services must become aware of where testing mistakes can occur and actively participate in designing processes to prevent mistakes. Most importantly, healthcare institutions need to adopt a culture of safety, which is implemented at all levels of the organization. This includes establishing closer links between providers of laboratory services and others in the healthcare delivery system. This was the theme of a 2003 Quality Institute Conference aimed at making the laboratory a key partner in patient safety. Plans to create a permanent public–private partnership, called the Institute for Quality in Laboratory Medicine, whose mission is to promote improvements in the use of laboratory tests and laboratory services are underway.Presented at the 9th Conference on Quality in the Spotlight, 18–19 March 2004, Antwerp, Belgium.     

三级相互作用对聚亚甲基链末端距四次矩的影响

本文用三级相互作用近似理论导出了高分子链末端距的四次矩的计算公式。计算聚亚甲基链的末端距四次矩,并同二级相互作用的结果进行了比较。对于聚亚甲基链,三级相互作用近似的四次矩小于二级相互作用近似的四次矩。     

铽离子荧光探针对酶与金属离子间能量转移和结合位的研究

应用荧光光度法研究了Ｔｂ＾３＋与牛胰脱氧核糖核酸酶（ＢＰＤ），枯草杆菌α－淀粉酶（ＢＳα－Ａ）的络合发光现象，实验表明，ＢＰＤ和ＢＳα－Ａ分别在ＰＨ＝７－８和５－６范围内与Ｔｂ＾３＋络合，并发射Ｔｂ＾３＋的特征荧光，Ｔｂ＾３＋与ＢＰＤ和ＢＳα－Ａ的络合比分别为２：１和４：１。并应用Ｆｏｒｓｔｅｒ理论测定了Ｔｂ＾３＋与ＢＰＤ和ＢＳα－Ａ之间能量传递的距离Ｒ分别为１．３９ｎｍ和１．４８ｎｍ，其临界距离     

The Use of Adiabatic Calorimetry for the Process Analysis and Safety Evaluation in Free Radical Polymerization

Adiabatic calorimetry is a technique that has been introduced as an important approach to hazard evaluation of exothermically reactive systems. In this paper the free radical polymerization of methyl methacrylate (MMA) has been studied. One of the most important aspects of MMA polymerization is its exothermicity and autoaccelerating behaviour, these characteristics can generate the occurrence of a runaway reaction.In a runaway situation the reacting system is close to adiabatic behaviour because it is unable to eliminate the heat that is being generated. An even worse situation can be reproduced in the laboratory with the Phi-Tec pseudo-adiabatic calorimeter. Process design parameters that are usually calculated from thermodynamic data or using semiempirical rules, such as adiabatic temperature rise or maximum attainable pressure, can be directly determined.The existence of the ceiling temperature has been experimentally demonstrated.This revised version was published online in November 2005 with corrections to the Cover Date.     

QSAR Studies on the COX-2 Inhibition by 3,4-Diarylcycloxazolones Based on MEDV Descriptor

Selective inhibition of cyclooxygenase-2 (COX-2) might avoid the side effects of current available nonsteroidal antiinflammatory drugs while retaining their therapeutic efficacy. A novel variable selection and modeling method based on prediction is developed to construct the quantitative structure-activity relationships (QSAR) between the molecular electronegativity distance vector (MEDV) based on 13 atomic types and the biological activities of a set of selective cyclooxygenase-2 inhibitory molecules, 3,4-diarylcycloxazolones (DAA) plus indomethacin,naproxen, and celecoxib. Using multiple linear regression, a 5-variable linear model is developed with the calibrated correlation coefficient of 0.9271 and root mean square error of 0.17 in modeling stage and the validated correlation coefficient of 0.9030 and root mean square error of 0.20 in leave-one-out validation step, respectively. To further test the predictive ability of the model, 20 DAA compounds are picked up to construct a training set which is used to build a QSAR model and then the model is employed to predict the biological activities of the balance compounds. The predicted correlation coefficient and root mean square error are 0.9332 and 0.19, respectively.     

ELASTIC BEHAVIOR OF PROTEIN-LIKE SINGLE CHAIN

The conformational properties and elastic behaviors of protein-like single chains in the process of tensile elongation were investigated by means of Monte Carlo method. The sequences of protein-like single chains contain two types of residues: hydrophobic (H) and hydrophilic (P). The average conformations and thermodynamics statistical properties of protein-like single chains with various elongation ratio λ were calculated. It was found that the mean-square end-to-end distance r increases with elongation ratio,λ. The tensor eigenvalues ratio of : decreases with elongation ratio λ for short (HP)x protein-like polymers, however, the ratio of : increases with elongation ratioλ,especially for long (H)x sequence. Average energy per bond increases with elongation ratioλ, especially for(H)x protein-like single chains. Helmholtz free energy per bond also increases with elongation ratioλ. Elastic force (f), energy contribution to force (fU) and entropy contribution to force (fs) for different protein-like single chains were also calculated.These investigations may provide some insights into elastic behaviors of proteins.     

Hazard in reaction of titanium raw materials with sulphuric acid

The reaction of ilmenite titanium raw material with sulphuric acid was investigated in ‘hazard’ type calorimetric system. The investigations show the essential influence of initial temperature, particle size distribution and concentration of sulphuric acid on rate and heat power of reaction and determine the limits of safety of the process and also its efficiency.     

聚合物异核交叉弛豫及二维NOE谱

The heteronuclear cross-relaxation rates in polymers were determined by selective and conventional ~(13)C spin-lattice relaxation experiments, the proton-carbon distances were calculated by the theoretical formula, and two-dimensional NOE spectra of the polymers were also measured. The results showed that (1) the measured proton-carbon distances coincide with the distances from molecular models, (2) there is the observable dipolar cross-relaxation effect between the quaternary carbons and their neighboring protons, and (3) the optimum mixing times depend on the relaxation properties of the proton and carbon.     

Influence of development distance on resolution in thin-layer chromatography

Theoretical equations are given to relate resolution with development distance. Comparative experiments undertaken with quaternary ammonium compounds as test substances and using a selection of basic drugs are presented. As expected, resolution decreases with shorter development distance. However, this effect is less pronounced for compounds with small R_f values and when the spot size at the starting point is kept small. It was also shown that, for correctly assessing resolution in relation to development distance, the amounts of material spotted have to be decreased for shorter development distances.