19 research outputs found

    Experimental Simulation of High Temperature Plasma Transport Using Almost Dimensionally Similar Cold Plasmas in the Compact Helical System

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    In the Compact Helical System (CHS), experimental simulation of high temperature plasma transport is attempted by using cold plasma having similar dimensionless parameters such as electron-ion collision frequency normalized by bounce frequency v*ei, averaged toroidal beta value βt and the normalized gyro radius ρs*. The cold plasma is produced by 2.45 GHz electron cyclotron waves at very low toroidal field less than 0.1 T, and has v*ei ~ 0.05?1, βt < 0.02 % and ρs* ~ 0.02?0.05. The radial profiles of fluctuation amplitude have similarity to those in a high temperature plasma. In the cold plasma with low v*ei < 0.1, internal transport barrier is clearly formed in electron density and temperature profiles when the radial electric field rapidly evolves to positive value

    Gene amplification of CCNE1, CCND1, and CDK6 in gastric cancers detected by multiplex ligation-dependent probe amplification and fluorescence in situ hybridization

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    New and effective treatments for advanced gastric cancer are urgently needed. Cyclins E and D1 form a complex with cyclin-dependent kinase 2, 4, or 6 to regulate G1-S transition. The G1-S regulatory genes encoding cyclin E (CCNE1), cyclin D1 (CCND1), and CDK6 (CDK6) are frequently amplified in gastric cancer and may therefore influence molecularly targeted therapies against ERBB2 or EGFR when coamplified. A total of 179 formalin-fixed and paraffin-embedded gastric cancer specimens were examined for these gene amplifications by multiplex ligation-dependent probe amplification and fluorescence in situ hybridization. Amplification of at least 1 G1-S regulatory gene was found in 35 tumors (CCNE1 amplification, 15% of samples; CCND1, 6%; CDK6, 1%). In 13 of the 35 tumors, dual-color fluorescence in situ hybridization identified coamplification of the G1-S regulatory genes with ERBB2, EGFR, and/or KRAS in single cancer nuclei. The observation that cells with G1-S regulatory gene amplification contained clonal subpopulations with coamplification of ERBB2, EGFR, or KRAS in 5 early and 3 advanced cancers suggests that amplification of the G1-S regulatory genes represents an early event, which precedes ERBB2, EGFR, or KRAS amplification. Amplified CCNE1, CCND1, and CDK6 in advanced gastric cancer may be potentially useful as direct targets for molecular therapy or for combination therapy with ERBB2 or EGFR inhibitors. Multiplex ligation-dependent probe amplification could be a useful tool for identification of patients who would benefit from such therapies. © 2016 Elsevier Inc.Embargo Period 12 month

    Semi-comprehensive analysis of gene amplification in gastric cancers using multiplex ligation-dependent probe amplification and fluorescence in situ hybridization

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    The prognosis of patients with gastric carcinomas at an advanced stage still remains dismal, and therefore novel therapeutic modalities are urgently needed. Since the successful targeting of amplified ERBB2 with a humanized monoclonal antibody, the amplified genes of other receptor tyrosine kinases such as EGFR, FGFR2, and MET, as well as those of other cell regulator genes, are being considered as candidate targets of molecular therapy. The aim of the present study was to determine the amplification status of 26 genes, which are frequently amplified in solid cancers, in advanced gastric cancers. A total of 93 formalin-fixed and paraffin-embedded advanced gastric cancer tissues were examined by multiple ligation-dependent probe amplification, and 32 cases with ‘gain’ or ‘amplified’ status of 16 genes were further examined for the respective gene amplification by fluorescence in situ hybridization (FISH) and for the respective protein overexpression by immunohistochemistry. The frequencies of gene amplifications in advanced gastric cancers were as follows: ERBB2 (13 cases, 14%), FGFR2 (7 cases, 8%), MYC (7 cases, 8%), TOP2A (7 cases, 8%), MET (4 cases, 4%), MDM2 (4 cases, 4%), CCND1 (3 cases, 3%), FGF10 (2 cases, 3%), and EGFR (1 case, 1%). Amplification of the receptor tyrosine kinases genes occurred in a mutually exclusive manner except for one tumor in which ERBB2 and FGFR2 were both amplified but in different cancer cells. Co-amplification of ERBB2 and MYC, and EGFR and CCND1, in single nuclei but on different amplicons, was confirmed in one case each. Attempts at correlating the FISH status with the immunohistochemical staining pattern showed variable results from complete concordance to no correlation. In conclusion, combination of multiple ligation-dependent probe amplification and FISH analysis is a feasible approach for obtaining the semi-comprehensive genetic information that is necessary for personalized molecular targeted therapy.Modern Pathology advance online publication, 6 March 2015; doi:10.1038/modpathol.2015.33

    Gene amplification of ESR1 in breast cancers-fact or fiction? A fluorescence in situ hybridization and multiplex ligation-dependent probe amplification study

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    Oestrogen receptor-alpha (ERα), encoded by the ESR1 gene located on 6q25, is a nuclear transcription factor. Since it was reported in 2007 that more than 20% of breast cancers show ESR1 gene amplification, there has been considerable controversy about its frequency and clinical significance. We set out to assess the frequency and levels of ESR1 amplification in breast cancers. In a total of 106 breast needle biopsy specimens examined by immunohistochemistry, 78 tumours contained more than 10% ERα-positive cancer cells. In fluorescence in situ hybridization (FISH) analysis with an ESR1-specific probe, variously extended ESR1 signals were found in ERα-expressing cells. Some of these were indistinguishable from large clustered signals generally accepted to mean high-level gene amplification in homogeneously staining regions (HSRs), and could be considered to represent gene amplification. However, with RNase treatment, the \u27HSR-like\u27 signals changed to small compact signals, and are thus thought to represent concentrated RNA. FISH using two differently labelled probes corresponding to the non-overlapping 5\u27- and 3\u27-end portions of the ESR1 gene on touch smears showed a preserved spatial relationship of the 3\u27 to 5\u27 sequence of ESR1, therefore strongly suggesting that the RNA consisted of primary transcripts. Using touch smears obtained from 51 fresh tumours, precise enumeration of ESR1 signals with a correction by the number of centromere 6 on FISH after RNase A treatment revealed that three tumours (5.9%) had tumour cells with one to three additional copies of ESR1 as predominant subpopulations. This infrequent and low level of gene amplification of ESR1 was also detected as a \u27gain\u27 of the gene by analysis with multiplex ligation-dependent probe amplification (MLPA). The consistent results from immunohistochemistry, FISH, and MLPA in the present study settle the long-standing debate concerning gene amplification of ESR1 in breast carcinoma. © 2012 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Lt

    Coordinated generation of multiple ocular-like cell lineages and fabrication of functional corneal epithelial cell sheets from human iPS cells

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    We describe a protocol for the generation of a functional and transplantable corneal epithelium derived from human induced pluripotent stem (iPS) cells. When this protocol is followed, a proportion of iPS cells spontaneously form circular colonies, each of which is composed of four concentric zones. Cells in these zones have different morphologies and immunostaining characteristics, resembling neuroectoderm, neural crest, ocular-surface ectoderm, or surface ectoderm. We have named this 2D colony a 'SEAM' (self-formed ectodermal autonomous multizone), and previously demonstrated that cells within the SEAM have the potential to give rise to anlages of different ocular lineages, including retinal cells, lens cells, and ocular-surface ectoderm. To investigate the translational potential of the SEAM, cells within it that resemble ocular-surface epithelia can be isolated by pipetting and FACS sorting into a population of corneal epithelial-like progenitor cells. These can be expanded and differentiated to form an epithelial layer expressing K12 and PAX6, and able to recover function in an animal model of corneal epithelial dysfunction after surgical transplantation. The whole protocol, encompassing human iPS cell preparation, autonomous differentiation, purification, and subsequent differentiation, takes between 100 and 120 d, and is of potential use to researchers with an interest in eye development and/or ocular-surface regeneration. Experience with human iPS cell culture and sorting via FACS will be of benefit for researchers performing this protocol

    Step-Climbing Tactics Using a Mobile Robot Pushing a Hand Cart

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    The present paper describes step-climbing tactics using a wheeled robot and a hand cart that has a hand brake. The robot has two arms that are used to hold or push the handle of the cart and a lower extendable wheel mechanism that can push against the bottom of the cart. Some of the manipulator joints are controlled passively when moving over the step. To lift the front wheels of the cart, the robot holds the handle steady and pushes against the bottom of the cart using the extendable wheel mechanism. This action is similar to that performed by a human. The robot then pushes the entire cart forward so that the front wheels of the cart are above the step. When the rear wheels of the cart have climbed the step, the upper-arm links of the manipulators are pressed against the robot chest to allow the robot to push the cart. When the cart has fully climbed the step, the robot then uses the cart to climb the step. The present paper describes the details of the robot system, and theoretical analyses were performed to determine the requirement of masses and the centers of gravity of both vehicles to lift the cart. Experiments were also carried out in which the robot was controlled using an intranet connection, and the results demonstrated the effectiveness of the proposed method
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