Microfluidic device with chemical gradient for single-cell cytotoxicity assays

Here, we report the fabrication of a chemical gradient microfluidic device for single-cell cytotoxicity assays. This device consists of a microfluidic chemical gradient generator and a microcavity array that enables entrapment of cells with high efficiency at 88 ± 6% of the loaded cells. A 2-fold logarithmic chemical gradient generator that is capable of generating a serial 2-fold gradient was designed and then integrated with the microcavity array. High density single-cell entrapment was demonstrated in the device without cell damage, which was performed in 30 s. Finally, we validated the feasibility of this device to perform cytotoxicity assays by exposing cells to potassium cyanide (0-100 μM KCN). The device captured images of 4000 single cells affected by 6 concentrations of KCN and determined cell viability by counting the effected cells. Image scanning of the microcavity array was completed within 10 min using a 10× objective lens and a motorized stage. Aligning cells on the microcavity array eases cell counting, observation, imaging, and evaluation of singular cells. Thus, this platform was able to determine the cytotoxicity of chemicals at a single-cell level, as well as trace the cytotoxicity over time. This device and method will be useful for cytotoxicity analysis and basic biomedical research.     

Improvement of the oblique-incidence optical interferometric system to measure tooth flanks of involute helical gears

We put forward a plan of improving the oblique-incidence optical interferometric system applied in the measurement of tooth flanks of an involute spur gear in order to expand its capability to measure an involute helical gear. On the basis of the features of an involute helical tooth flank, we discuss how to realize the parallelism between the optical axis of the object arm of the optical system and the straight lines constructing the involute helical tooth flank. This parallelism helps the optical system produce an interference fringe pattern as clear as the one of an involute spur gear [Appl. Opt.49, 6409 (2010).]. A numerical simulation is then performed to examine the correctness of the improvement. During simulating, we unify the equation of difference tooth flanks by means of importing two parameters in relation to the left or right side of a tooth flank and the helical direction of teeth, respectively. Finally, the actual experiment is fulfilled through the real optical system built on an optical table. The simulation and experiment results verify the correctness and feasibility of the proposed improvement.     

Deoxidation of Ti Melt by Newly Developed Two-Step Plasma Arc Melting Process Using Hydrogen

Metallurgical and Materials Transactions B - A two-step plasma arc melting process, comprising a first step under Ar-30 pct H2 gas flow and the second step under Ar gas flow, has been...     

Administration-time-dependent effects of diltiazem on the 24-hour blood pressure profile of essential hypertension patients

Cells of the central nervous system (CNS) normally do not express detectable levels of major histocompatibility complex (MHC) Class I antigens. However, MHC Class I expression can be induced after virus infection. We tested the hypothesis that virus-induced Class I expression is mediated by lymphocytes or cytokines using lymphocyte- and cytokine-deficient mice. We used Theiler's murine encephalomyelitis virus (TMEV), which induces CNS demyelination that maps genetically to the D region of MHC Class I and is associated with high levels of Class I products. TMEV infection of severe combined immunodeficiency (SCID) and recombination activation gene-1-deficient mice, which lack B and T lymphocytes, resulted in equivalent H-2D and H-2K expression in brain and spinal cord, according to analysis of the area and intensity of immunoperoxidase staining. Class I antigens were demonstrated as early as 6 hours after infection, and they were more widely distributed than viral RNA, indicating that expression was induced indirectly via a soluble factor. To determine whether cytokines induced the expression, we infected mice lacking receptors for interferon-alpha/beta (IFN-alpha/beta R (-/-)), interferon-gamma (IFN-gamma R(-/-)), and tumor necrosis factor-alpha (TNFRp55(-/-)). TMEV-infected IFN-gamma R(-/-) and TN-FRp55(-/-) mice expressed Class I antigens in the CNS, whereas IFN-alpha/beta R(-/-) mice did not, establishing that IFN-alpha/beta mediated the expression. In contrast to the equivalent expression in SCID mice, we observed greater area and higher intensity of H-2D versus H-2K antigens in infected SCID mice reconstituted with normal spleen cells. Collectively, the data indicate that after TMEV infection, early generalized MHC Class I expression is mediated by IFN-alpha/beta independently of lymphocytes, but the differential regulation of H-2D over H-2K may be controlled by B and/or T lymphocytes.     

Multiple mechanisms in the perception of face gender: Effect of sex-irrelevant features.

Effects of sex-relevant and sex-irrelevant facial features on the evaluation of facial gender were investigated. Participants rated masculinity of 48 male facial photographs and femininity of 48 female facial photographs. Eighty feature points were measured on each of the facial photographs. Using a generalized Procrustes analysis, facial shapes were converted into multidimensional vectors, with the average face as a starting point. Each vector was decomposed into a sex-relevant subvector and a sex-irrelevant subvector which were, respectively, parallel and orthogonal to the main male–female axis. Principal components analysis (PCA) was performed on the sex-irrelevant subvectors. One principal component was negatively correlated with both perceived masculinity and femininity, and another was correlated only with femininity, though both components were orthogonal to the male–female dimension (and thus by definition sex-irrelevant). These results indicate that evaluation of facial gender depends on sex-irrelevant as well as sex-relevant facial features. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

A genetic algorithm for the optimal sequential partitioning problem

The optimal sequential problem is defined as the problem of finding the minimum cost partition of the nodes of a directed acyclic graph into subsets of a given size, subject to the constraint that the precedence relationships among the elements are satisfied. A heuristic algorithm based on tabu search has been proposed for this problem [2]. However, there is a tendency for the solutions obtained by tabu search to become trapped in bad local optima in parallel graphs with random edge costs. In this paper we present a genetic algorithm for the optimal sequential partitioning problem. We develop an effective two‐point partial order crossover satisfying sequential conditions, which preserve better blocks that have a larger sum of edge costs. In this crossover we introduce the roulette selection method to escape local optima. We also assess the effectiveness of the algorithm. The results show that this proposed algorithm outperforms any other algorithm using tabu search in terms of solution quality. © 2001 Scripta Technica, Electr Eng Jpn, 135(4): 43–51, 2001     

Development of restoration system based on human performance model

A stable power supply is required from power systems as the importance of electrical energy increases. Particularly, in the case of high-voltage systems (500-, 275-, 154-kV bulk power systems), this requirement is high. However, there are cases when power system faults cannot be avoided. Accordingly, it is very important to restore power systems quickly and safely if these failures occur. The characteristics of the power system restoration (its combinatorial aspects, use of knowledge from a wide variety of origins and of different types, number of criteria to satisfy) make it a difficult problem, for which the use of expert systems to generate restoration plans is being considered by many researchers, and promising results have already been obtained. However, most systems are still in the prototype stage [1]. One reason seems to be the lack of studies of a support system for knowledge-based behavior (unable to describe with any rule). This paper analyzes first power system restoration based on the human performance model [6] and discusses the knowledge-based behavior that is a high conceptual level of human performance to solve the problem from the combinatorial viewpoint. Then the application for the trunk line dispatching center is reported. Finally, the relations between knowledge-based behavior and the designed human interfaces are verified with a power networks restoration case-study.     

Twist form of teleocidin derivatives is active in in vivo tumor promotion by (-)-benzolactam-V8-310

Two patients, both 70 years old, operated for differentiated thyroid cancer with foci of undifferentiated tumor (one papillary containing pseudosarcomatoid foci, the other with insular pattern containing undifferentiated foci) suddenly died. In both cases, for both of them metastatic involvement of the myocardium and endocardium. These original findings suggest that elderly patients suffering rom well differentiated thyroid cancer, containing undifferentiated foci, therefore suspected to have metastasized, would benefit from non-invasive cardiac work-up (sonogram) in order to plan their multidisciplinary treatment.     

主轴转速对半导体芯片切割品质的影响

针对目前大量使用的有机材料基板芯片和使用量相对较少的铜板基板芯片，分别设计了一组实验，并对由实验切割出来的芯片的主要评价项目逐项进行了检测，明确了主轴转速对两种芯片的外形尺寸误差、芯片的喇叭口现象、切断面的角度误差、崩碎坑的数量和大小、表面粗糙度等的影响；得出了不管是哪一种基板的芯片，出现不合格的主要是崩碎坑指标这一结论。通过分析和比较，得出了实际使用的主轴转速不宜低于15000r／min这一对于高速切割机的设计和切割工艺的制定具有重要参考价值的结论。