Number Of Different Cells Research Articles

Performance-Constrained Transistor Sizing for Different Cell Count Minimization

A continuously-sized circuit resulting from transistor sizing consists of gates with a large variety of sizes. In the standard cell based design flow where every gate is implemented by a cell, a large number of different cells need to be prepared to implement an entire circuit. In this paper, we first provide a formal formulation of the performance-constrained different cell count minimization problem, and then propose an effective heuristic which iteratively minimizes the number of cells under performance constraints such as area, delay and power. Experimental results on the ISCAS 85 benchmark circuits implemented in a 90nm fabrication technology demonstrate that different cell counts are reduced by 74.3% on average while accepting a 1% delay degradation. Compared to circuits using a typical discretely-sized cell library, we also demonstrate that the proposed method can generate better circuits using the same number of cells.

Identification of a highly specific and versatile vitamin D receptor antibody

The active form of vitamin D, 1alpha,25-dihydroxyvitamin D 3 (1,25(OH) 2D 3) is critical for regulation of serum calcium and phosphorus levels and for proper maintenance of bone mineralization and neuromuscular function. Biological effects of 1,25(OH) 2D 3 are mediated through a nuclear steroid hormone receptor, known as the vitamin D receptor (VDR). The discovery of VDR in a number of different cell and tissue types, suggests that the physiological role of vitamin D may extend beyond the regulation of calcium homeostasis and bone function. Unfortunately, identification of tissues expressing VDR has been controversial due to low abundance of the receptor and quality of the antibodies used. Therefore, we elected to characterize a panel of commercially available VDR antibodies in order to identify antibodies with high specificity and sensitivity. To address these objectives, we have used multiple immunoassays to determine VDR expression in tissues from several organs from multiple species employing tissues from VDR knockout mice as critical negative controls. Many of the antibodies tested showed nonspecific binding that can account for divergent reports. However, one antibody, identified as D-6, is highly specific and extremely sensitive. The specificity, sensitivity, and versatility of this antibody make it the preferred antibody for identifying VDR expression in target tissues using immunological methods.

A key geometric parameter for the flow uniformity in planar solid oxide fuel cell stacks

Intensive CFD calculations are performed for the flow distribution in planar solid oxide fuel cell (SOFC) stacks with different number of cells. The calculations are based on 3D models with realistic geometric and operational parameters. The effects of design parameters, such as the channel height and length, the height of the repeating cell unit and the manifold width, on the flow uniformity are examined. The CFD results demonstrate that the ratio of the outlet manifold width to the inlet manifold width (α) is a key design parameter that affects the flow uniformity. The physical origin for the effect of α on the flow distribution is discussed and a simplified 2D model with the critical details of the flow physics is developed. The 2D model provides quality result for the optimal value of α and is easy to use for the broad engineering society.

IMPLEMENTING HIRSCHBERG'S PRAM-ALGORITHM FOR CONNECTED COMPONENTS ON A GLOBAL CELLULAR AUTOMATON

The GCA (Global Cellular Automata) model consists of a collection of cells which change their states synchronously depending on the states of their neighbors like in the classical CA model. In differentiation to the CA model the neighbors are not fixed and local, they are variable and global. The GCA model is applicable to a wide range of parallel algorithms, and it can be implemented on reconfigurable hardware. We discuss the GCA implementation of PRAM algorithms on reconfigurable hardware (Field Programmable Gate Array, FPGA), exemplified by the algorithm of Hirschberg et al., which determines the connected components of a given undirected graph. We provide two implementations with different numbers of cells: one with maximum parallelism and a compact one. We compare the implementation complexities, i.e. number of FPGA cells of both implementations, and thus present experimental evidence of our claims. The GCA(N) algorithm uses 3n cells with time complexity O(n log n), whereas the GCA(N2) algorithm uses n(n + 1) cells with time complexity O( log 2 n). The GCA(N) algorithm is more economic with respect to resources (logic × execution time) whereas the GCA(N2) algorithm can produce the result faster with a speedup of O((n+m)/ log n). Further insights are that efficient mappings of PRAM algorithms onto GCA exist, and that PRAM and GCA optimality criteria differ because the latter takes memory consumption into account. This makes the GCA a parallel computational model and an implementation platform, thus narrowing the gap between theory and practice.

Cell growth suppression by thanatos-associated protein 11(THAP11) is mediated by transcriptional downregulation of c-Myc

Thanatos-associated proteins (THAPs) are zinc-dependent, sequence-specific DNA-binding factors involved in cell proliferation, apoptosis, cell cycle, chromatin modification and transcriptional regulation. THAP11 is the most recently described member of this human protein family. In this study, we show that THAP11 is ubiquitously expressed in normal tissues and frequently downregulated in several human tumor tissues. Overexpression of THAP11 markedly inhibits growth of a number of different cells, including cancer cells and non-transformed cells. Silencing of THAP11 by RNA interference in HepG2 cells results in loss of cell growth repression. These results suggest that human THAP11 may be an endogenous physiologic regulator of cell proliferation. We also provide evidence that the function of THAP11 is mediated by its ability to repress transcription of c-Myc. Promoter reporter assays indicate a DNA binding-dependent c-Myc transcriptional repression. Chromatin immunoprecipitations and EMSA assay suggest that THAP11 directly binds to the c-Myc promoter. The findings that expression of c-Myc rescues significantly cells from THAP11-mediated cell growth suppression and that THAP11 expression only slightly inhibits c-Myc null fibroblasts cells growth reveal that THAP11 inhibits cell growth through downregulation of c-Myc expression. Taken together, these suggest that THAP11 functions as a cell growth suppressor by negatively regulating the expression of c-Myc.

Advances in the development of a hydrogen/oxygen PEM fuel cell stack

Recent advances in the design and construction of a hydrogen/oxygen PEM fuel cell stack are presented. A test bench including measurement and control devices to monitor the fuel cell operating parameters was mounted. The influence of the characteristics of the membrane electrode assembly, bipolar plates, etc., on the performance of the fuel cell stack was studied. The behavior of the fuel cell stack with a different number of cells in series was evaluated. In order to identify and minimize the energy losses a critical analysis of the results was done.

Detecting biological associations between genes based on the theory of phase synchronization

This study presents a novel approach to detect biological associations for gene pairs with cell cycle-specific expression profiles. Previous studies have shown that periodic transcription is commonly regulated by transcription factors that are also periodically transcribed, and there is a growing number of examples where cell cycle regulated genes are conserved in yeast and mammalian cells. Some genes have periodicity for their oscillatory activity throughout cell division. These cell cycle-specific oscillatory activities could be explained by a biological phenomenon in terms of efficiency and logical order. In the yeast data used in this study, about 13% of genes behave in this manner based on a previous yeast study. Microarrays have been applied to determine genome-wide expression patterns during the cell cycle of a number of different cells. Moreover, several previous studies have shown that many pairs of genes, which have linearly correlated expression profiles, have similar cellular roles or physical interactions. Based on this point of view, the traditional clustering methods have focused on similar expression profiles based on the premise that genes with similar expression profiles have similar biological functions or relevant biological interactions. However, there are a number of previous studies indicating that the expression of some genes may be delayed compared to others due to a time lag in their transcriptional control. Therefore, we propose a novel clustering method, named as phase-synchronization clustering, based on the theory of phase synchronization for detecting biological associations using cell cycle-specific expression profiles. We evaluate phase-synchronization clustering here using Saccharomyces cerevisiae microarray data. Phase-synchronization clustering is able to detect biologically associated gene pairs that have linearly correlated (simultaneous and inverted) as well as time-delayed expression profiles. The performance of phase-synchronization clustering is compared with other conventional clustering methods. The likelihood of finding relevant biological associations by phase-synchronization clustering is significantly higher than other clustering methods. Therefore, phase-synchronization clustering is more efficient for detecting known biological interactions for gene pairs than other conventional clustering methods for analyzing cell cycle-specific expression data. The evaluation analysis of the results by phase-synchronization clustering also suggests that the cellular activities during the cell division process could be understood as a phenomenon of collective synchronization.

Cell adhesion and cortex contractility determine cell patterning in the Drosophila retina

Because of the resemblance of many epithelial tissues to densely packed soap bubbles, it has been suggested that surface minimization, which drives soap bubble packing, could be governing cell packing as well. We test this by modeling the shape of the cells in a Drosophila retina ommatidium. We use the observed configurations and shapes in wild-type flies, as well as in flies with different numbers of cells per ommatidia, and mutants with cells where E- or N-cadherin is either deleted or misexpressed. We find that surface minimization is insufficient to model the experimentally observed shapes and packing of the cells based on their cadherin expression. We then consider a model in which adhesion leads to a surface increase, balanced by cell cortex contraction. Using the experimentally observed distributions of E- and N-cadherin, we simulate the packing and cell shapes in the wild-type eye. Furthermore, by changing only the corresponding parameters, this model can describe the mutants with different numbers of cells or changes in cadherin expression.

Adhesion molecules in the regulation of CNS myelination

Myelination is necessary both for rapid salutatory conduction and the long-term survival of the axon. In the CNS the myelin sheath is formed by the oligodendrocytes. Each oligodendrocyte myelinates several axons and, as the number of wraps around each axon is determined precisely by the axon diameter, this requires a close, highly regulated interaction between the axons and each of the oligodendrocyte processes. Adhesion molecules are likely to play an important role in the bi-directional signalling between axon and oligodendrocyte that underlies this interaction. Here we review the current knowledge of the function of adhesion molecules in the different phases of oligodendrocyte differentiation and myelination, and discuss how the properties of these proteins defined by other cell biological systems indicates potential roles in oligodendrocytes. We show how the function of a number of different adhesion and cell-cell interaction molecules such as polysialic acid neural cell adhesion molecule, Lingo-1, Notch, neuregulin, integrins and extracellullar matrix proteins provide negative and positive signals that coordinate the formation of the myelin membrane. Compiling this information from a number of different cell biological and genetic experiments helps us to understand the pathology of multiple sclerosis and direct new areas of research that might eventually lead to potential drug targets to increase remyelination.

Patterning of Embryonic Stem Cells Using the Bio Flip Chip

Cell-cell interactions consisting of diffusible signaling and cell-cell contact (juxtacrine signaling) are important in numerous biological processes such as tumor growth, stem cell differentiation, and stem cell self-renewal. A number of methods currently exist to modulate cell signaling in vitro. One method of modulating the total amount of diffusible signaling is to vary the cell seeding density during culture. Due to the random nature of cell seeding, this results in considerable variation in the actual cell-cell spacing and amount of cell-cell contact, and cannot prescribe the local environment. A more specific approach for modulating cell signaling is to use molecular inhibitors or genetic approaches to knock down specific signaling proteins, but both of these methods are best suited to manipulating small numbers of molecules. Here, we demonstrate a new approach to modulating cell-cell signaling that modulates the local environment of a cluster of cells by placing different numbers of cells at desired locations on a substrate. This method provides a complementary way to control the local diffusible and juxtacrine signaling between cells. Our method makes use of the Bio Flip Chip (BFC), a microfabricated silicone chip containing hundreds-to-thousands of microwells, each sized to hold either a single cell or small numbers of cells. We load the chip with cells simply by pipetting them onto the array of wells and washing unloaded cells off the array. The chip is then flipped onto a substrate, whereby the cells fall out of the wells and onto the substrate, maintaining their patterning. After the cells have attached, the chip can be removed (or left on). This approach to cell patterning is unique in that it: 1) doesn't alter the chemistry of the substrate, thus allowing cells to proliferate and migrate; 2) allows patterning onto any substrate, including tissue-culture polystyrene, glass, matrigel, and even feeder cell layers; and 3) is compatible with traditional microcontact printing, allowing the creation of extracellular matrix islands with cells placed inside those islands. In this video, we demonstrate the patterning of mouse embryonic stem cells onto tissue-culture polystyrene using the BFC.

The effect of Ginkgo Biloba Extract on the expression of PKCα in the inflammatory cells and the level of IL-5 in induced sputum of asthmatic patients

To investigate the effect of the Ginkgo Biloba Extract (GBE) on the asthma and examine its possible mechanisms, 75 asthma patients were divided into 4 groups and the patients were respectively treated with fluticasone propionate for 2 weeks or 4 weeks, or treated with fluticasone propionate plus GBE for 2 weeks or 4 weeks. Fifteen healthy volunteers served as healthy controls. Sputum inhalation with inhaling hypertonic saline (4%-5%) was performed. Lung ventilatory function and forced expiratory volume in one second (FEV1) were measured. The numbers of different cells in induced sputum were calculated. The expression of PKCalpha in the cells was immunocytochemically detected and the percentages of positive cells in different cells were counted. Interleukin-5 (IL-5) in sputum supernatants was detected with enzyme-linked immunosorbent assay. The percentage of eosinophils, lymphocytes, PKCalpha positive inflammatory cells and the concentration of IL-5 in asthmatic patients were higher than those in the controls (P<0.05), and the eosinophils, lymphocytes, positive expression of PKCalpha and the level of IL-5 were significantly decreased in asthmatic patients after they were treated with fluticasone propionate or fluticasone propionate plus GBE. However, they were still significantly higher than those of the controls. Compared to the group treated with glucocorticosteroid for 2 weeks, no significant decrease was found in the percentage of eosinophils, lymphocytes, PKCalpha positive inflammatory cells and the IL-5 in the supernatant of induced sputum. Compared with the group treated with glucocorticosteroid for 2 or 4 weeks, significant decrease in the same parameters was observed in the group treated with fluticasone propionate and GBE for 4 weeks. The IL-5 level in the supernatant of induced sputum was positively correlated with the percentage of PKCalpha-positive inflammatory cells and the percentage of eosinophils in the induced sputum in asthma patient groups respectively (n=150, r= 0.83, P<0.01; n=150, r=0.76, P<0.01). The FEV1 was negatively correlated with the percentage of PKCalpha-positive inflammatory cells and the IL-5 levels in supernatant of induced sputum in asthma patients respectively (n=150, r=-0.77, P<0.01; n=150, r= -0.64, P<0.01). It is concluded that GBE could significantly decrease the infiltration of inflammatory cells such as eosinophils and lymphocytes in the asthmatic airway and relieve the airway inflammation. GBE may decrease the activation of the PKCalpha in the inflammatory cells and thereby decrease the IL-5 level in induced sputum. GBE may be used as a complement to the glucocorticosteroid therapy for asthma.

Disseminated isolated tumor cells in bone marrow of esophageal cancer cases

In this study, we reviewed reports on the clinical significance of isolated tumor cells (ITC) in the bone marrow of patients with esophageal cancer and other solid tumor malignancies. We examined studies on bone marrow as a target organ for ITC identification and also looked at the appropriate sites and most efficient methodologies for bone marrow extraction to evaluate the presence of ITC. A diverse number of different cells exist in bone marrow, and it is important to distinguish disseminated cancer cells from other cell types, such as progenitor cells and endothelial cells. Among the various types of cells found in the bone marrow, we confirmed the presence of disseminated cells that can proliferate under specific cell culture conditions. Finally, we discuss recent studies related to the clinical significance of ITC in bone marrow that are associated with prognosis or recurrence in cases of solid cancers, including esophageal cancer. We concluded that the clinical significance of bone marrow as the target organ for identification of ITC varies among different types of cancer and that further study is required to determine a bona fide marker for predicting prognosis or recurrence in cases of esophageal cancer.

Natural Balance of Multicell Converters: The General Case

This paper focuses on the development of the natural balancing theory for the p-cell case. It describes the relationship between the models for different numbers of cells in a generic model for a p-cell multicell converter. The model discussed is based on the same principles that were used to develop the two-cell model in , except that the mathematics is much more involved. The same conclusions that were found to be true for the two-cell case was also found to be true for the general case of p cells. These conclusions include that the natural balancing mechanism of multicell converters depends on the overlap of the groups of harmonics of the switching function as well as on the load impedance. It will also be shown that the self-balancing mechanism ensures safe operation under most operating conditions where a high enough switching frequency is chosen and the load is not purely reactive. Two new aspects of the balancing theory were identified in the p-cell case: 1) for fixed duty-cycle modulation there exists certain values of the duty-cycle that causes the natural balancing mechanism to fail and 2) for p-cell converters the balance booster concept can be extended to a number of balance boosters tuned to multiples of the switching frequency. A DesignTool based on the balancing theory was developed to aid practicing engineers in designing multicell converters

Simulation and experimental observation of contact conditions between stents and artery models

Treatment of coronary artery stenosis with percutaneous coronary angioplasty and stenting is sometimes complicated by neointimal hyperplasia, possibly due to interaction of the stent with the arterial wall within a specific contact area. Therefore, we characterized the stress distribution at the contacts between the stent and the artery using mathematical and experimental modeling (an arterial cylinder model with a tube-like structure and an arterial stenosis model, consisting of a tube and plaque portion) and two kinds of link stents with different numbers of cells and links. First, the contact condition was investigated using a finite element method (FEM). Second, experimental visualization of the contact area between the stent and the artery models was performed. Comparison of the experimental results with the FEM analysis revealed that the contact area between the stent (with a high number of cells and links) and the artery model was distributed over the total surface of the stent. Further, values obtained from the experimental distribution and the calculated distribution were similar. These data indicate that experimental modeling and FEM analysis are useful methods for analyzing the relationship between stent structure and stent/wall stress distributions and may help guide the design of new stents.

Vitamin D receptor is required to control gastrointestinal immunity in IL‐10 knockout mice

The vitamin D receptor (VDR) is a nuclear receptor expressed in a number of different cells of the immune system. This study was performed to determine the effect of VDR deficiency on immune function and inflammation of the gastrointestinal tract in a model of inflammatory bowel disease, namely interleukin-10 (IL-10) knockout mice. IL-10 knockout mice were generated which either could or could not respond to vitamin D (double IL-10/VDR knockout; DKO). The distribution and function of lymphocytes in both the primary and secondary lymphoid organs were compared and determined as a function of the severity of intestinal inflammation. DKO mice had normal thymic development and peripheral T-cell numbers at 3 weeks of age, but a week after intestinal disease was detected the thymus was dysplastic with a reduction in cellularity. The atrophy was coupled with increased apoptosis. The spleen weight of DKO mice increased as a result of the accumulation of red blood cells; however, there was a 50% reduction in the numbers of T and B cells. Conversely, the mesenteric lymph nodes were enlarged and contained increased numbers of lymphocytes. The T cells from DKO mice were of a memory phenotype and were hyporesponsive to T-cell receptor stimulation. Colitis in the DKO mice was associated with local and high expression of IL-2, interferon-gamma, IL-1beta, tumour necrosis factor-alpha and IL-12. The primary and secondary lymphoid organs in DKO mice are profoundly altered as a consequence of the fulminating inflammation in the gastrointestinal tract. VDR expression is required for the T cells and other immune cells to control inflammation in the IL-10 KO mice.

Cognitive neural prosthetics

Cognitive neural prosthetics

Effect of number of unit cells of fcc photonic crystal on property of band gaps

The effect of number of unit cells of the fcc photonic crystals on the property of the band gaps was investigated experimentally. Fcc photonic crystals with different numbers of cells were fabricated by using recording materials of different thickness in holography. Their transmitted spectra of the band gaps were measured. A guiding rule was given: a photonic crystal which can be practically used should have 50 unit cells at least.

3937 テイラー渦流れの各種物理量による特徴抽出に関する数値的研究(J08-2 流体情報学と発見科学(2),J08 流体情報学と発見科学)

Taylor vortex flow appears between two concentric rotating cylinders, for example, fluid bearings of bard disks etc. It is important to investigate Taylor vortex flow in order to control flows. When the velocity of inner cylinder changes, the flow suddenly becomes unstable and develops into vortex flow having different number of cells. Cylinder torque applied to the cylinder walls and mean kinetic energy change sharply, and it leads to the deterioration and destruction of the container. In this study, the effects of cylinder length, angular velocity and, in particular, the kinematical dimensionless energy, are examined in detail when cylinder length is almost identical to difference between the radii of inner and outer cylinders.

Heterogeneity of Cancer Risk Due to Stochastic Effects

Persons with exactly the same genetic background, behavior, environment, etc. may have differences in cancer risk due to a different number of cells on the way to malignancy. These differences are estimated quantitatively by using the two-stage clonal expansion model. For liver cancer the estimated relative risk for persons without intermediate cells at age 40 is less than 10% when compared to the risk of the total population, while the top 0.1% risk group has a more than 100-fold risk compared to the population. The risk of the 1% percentile in risk is more than 100-fold of the risk of the more than 95% persons without intermediate cells. The number of intermediate (premalignant) cells in the risk groups cannot be calculated from incidence data only because they depend strongly on a nonidentifiable parameter. But under plausible assumptions, less than about 1,000 intermediate cells are present at age 40 even in high-risk persons.

Subversion of immune cell signal transduction pathways by the secreted filarial nematode product, ES-62

Filarial nematodes achieve longevity within the infected host by suppressing and modulating the host immune response. To do this, the worms actively secrete products that have been demonstrated to possess immunomodulatory properties. In this article we discuss the immunomodulatory effects of the phosphorylcholine-containing filarial nematode secreted glycoprotein ES-62. In particular we describe how it modulates intracellular signal transduction pathways in a number of different cells of the immune system, in particular B-lymphocytes, T-lymphocytes, macrophages and dendritic cells.