Biomarkers in pediatrics: children as biomarker orphans

Biomarkers have enormous potential to improve patient care by establishing tests of diagnosis, prognosis, and treatment effects. Successfully translating a biomarker from discovery to clinical application demands high-quality discovery research and high-quality clinical studies for biomarker validation; however, there are additional challenges that face biomarker research in pediatrics. There are also additional characteristics of pediatric medicine that make biomarker research especially needed. This review focuses on the fundamentals of biomarkers, the additional considerations needed for applying biomarker research to children, and recommendations for advancing pediatric biomarker research.     

Lighting level and productivity: a field study in the electronics industry

The effect of illuminance on the speed and the quality (percentage of errors) with which workers assemble electronic devices was studied in an electronics factory in The Netherlands. For the study, the horizontal illuminance was alternated per work shift between 800 and 1200 lux. The first test was done during the summer and a second test during the winter. A significant effect of illuminance has been found. With 1200 lux at the working plane, the speed of production in the summer was 2.9% higher than with 800 lux. In the winter it was 3.1% higher with the increased illuminance. There was no significant effect of the illuminance on the percentage of errors.     

Investigation of the levels of free purine and pyrimidine bases and metabolites in mechanically recovered meats

Levels of free purine and pyrimidine bases and metabolites, in particular xanthine, have been investigated in poultry meat and MRM as potential qualitative or quantitative markers for the presence of MRM in meat products. Only xanthine was found to exhibit significantly different levels between the source meat and MRM product where, for example, it was found to be present at approximately 100 μg/g in turkey MRM but only 57, 33 and 14 μg/g in the neck, leg and breast meat respectively. The wide variation in levels within a cut, together with the overlap between figures for source meat and MRM, preclude the use of xanthine as a robust qualitative or quantitative marker. Processing of turkey meat by subjecting it to an increasing level of comminution does not appear to elevate the indigenous level of free xanthine.     

Temporal alignment of tissue and arterial data and selection of integration start times for the H(2)(15)O autoradiographic CBF model in PET

A technique has been developed and tested that provides an automated method of temporally aligning the PET tissue activity curve with the arterial activity curve for quantification of cerebral blood flow using the H(2)(15)O autoradiographic model. This technique not only determines the relative time delay between the two curves, but also provides the start time of integration. Variability in computing global cerebral blood flow using this technique is shown to be less than that obtained by trained observers manually selecting parameters and at least as good as that obtained by using another automated alignment technique.     

Unstable resonator misalignment in ring and linear toroidal resonators

Optical axis motion in a ring resonator is investigated as a function of resonator mirror misalignment by constructing an equivalent paraxial model and applying the ray matrix formalism. Analytical expressions are derived for the optical axis motion. The paraxial model of the ring is shown to imply a linear resonator as a specific case, and the ring resonator expressions collapse to the familiar Krupke-Sooy results for that case. Using this method, new misalignment expressions are determined for more complex linear resonators. Uncorrectable misalignment conditions caused by toroidal mirror parameter errors are studied analytically and with a geometric optics code, and resulting phase front errors are given for a special case. These results are also examined as a basis for toroidal mirror quality specifications.     

粘胶长丝生产使用的耐磨损玻璃漏斗

江苏省昆山市昆山佳成科技电器有限公司与丹东化纤公司合作，对传统的玻璃漏斗进行深加工，提高了其耐磨损性能。     

“空间位阻胺”脱碳技术在我厂的应用

一、前言天津碱厂现有以重油为原料的5万吨台成氨生产装置一套,净化系统流程为:中变一脱硫(A.D.A)—一次(粗)脱碳—脱硫(氧化锌)—低变—二次(精)脱碳—甲烷化。两次脱碳的吸收和再生分别自成系统,     

AR估计滤波误差能量最小二乘递推法

利用滤波误差能量给出了一个新的最小二乘快速递推算法。数值试验表明，该算法计算稳定性好，对噪声不敏感，能快速递推到高阶模型，并将该算法同Ｍａｒｐｌｅ算法等作了比较。     

Parallel global optimization with the particle swarm algorithm

Present day engineering optimization problems often impose large computational demands, resulting in long solution times even on a modern high-end processor. To obtain enhanced computational throughput and global search capability, we detail the coarse-grained parallelization of an increasingly popular global search method, the particle swarm optimization (PSO) algorithm. Parallel PSO performance was evaluated using two categories of optimization problems possessing multiple local minima-large-scale analytical test problems with computationally cheap function evaluations and medium-scale biomechanical system identification problems with computationally expensive function evaluations. For load-balanced analytical test problems formulated using 128 design variables, speedup was close to ideal and parallel efficiency above 95% for up to 32 nodes on a Beowulf cluster. In contrast, for load-imbalanced biomechanical system identification problems with 12 design variables, speedup plateaued and parallel efficiency decreased almost linearly with increasing number of nodes. The primary factor affecting parallel performance was the synchronization requirement of the parallel algorithm, which dictated that each iteration must wait for completion of the slowest fitness evaluation. When the analytical problems were solved using a fixed number of swarm iterations, a single population of 128 particles produced a better convergence rate than did multiple independent runs performed using sub-populations (8 runs with 16 particles, 4 runs with 32 particles, or 2 runs with 64 particles). These results suggest that (1) parallel PSO exhibits excellent parallel performance under load-balanced conditions, (2) an asynchronous implementation would be valuable for real-life problems subject to load imbalance, and (3) larger population sizes should be considered when multiple processors are available.