3,387 research outputs found

    Magnetism in reduced dimensions

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    We propose a short overview of a few selected issues of magnetism in reduced dimensions, which are the most relevant to set the background for more specialized contributions to the present Special Issue. Magnetic anisotropy in reduced dimensions is discussed, on a theoretical basis, then with experimental reports and views from surface to single-atom anisotropy. Then conventional magnetization states are reviewed, including macrospins, single domains, multidomains, and domain walls in stripes. Dipolar coupling is examined for lateral interactions in arrays, and for interlayer interactions in films and dots. Finally thermally-assisted magnetization reversal and superparamagnetism are presented. For each topic we sought a balance between well established knowledge and recent developments.Comment: 13 pages. Part of a Special Issue of the C. R. Physique devoted to spinelectronics (2005

    Percutaneous Cardiopulmonary Support-Supported Percutaneous Coronary Intervention: A Single Center Experience

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    BACKGROUND AND OBJECTIVES: Percutaneous cardiopulmonary support (PCPS) has proven to be a valuable technique in high-risk coronary patients undergoing percutaneous coronary intervention (PCI). However, there have been few studies on PCI associated with PCPS in Korea. We summarized our experience with PCPS-supported PCI. SUBJECTS AND METHODS: We retrospectively reviewed 19 patients with PCPS-supported PCI between August 2005 and June 2009. PCPS was used as an elective procedure for 10 patients with at least two of the following conditions: left-ventricular ejection fraction <35%, target vessel(s) supplying more than 50% of the viable myocardium, high risk surgical patients, and patients who refused coronary bypass surgery. In the remaining 9 patients PCPS was used as an emergency procedure, to stabilize and even resuscitate patients with acute myocardial infarction and cardiogenic shock, in order to attempt urgent PCI. RESULTS: Among the 19 patients who were treated with PCPS-supported PCI, 11 (57.9%) survived and 8 (42.1%) patients did not. ST elevation myocardial infarction with cardiogenic shock was more prevalent in the non-survivors than in the survivors (75% vs. 27.3%, p=0.04). The elective PCPS-supported PCI was practiced more frequently in the survivors than in the non-survivors (72.7% vs. 25%, p=0.04). In the analysis of the event-free survival curve between elective and emergency procedures, there was a significant difference in the survival rate (p=0.025). Among the survivors there were more patients with multi-vessel disease, but a lower Thrombolysis in Myocardial Infarction grade in the culprit lesions was detected in the non-survivors, before PCI. Although we studied high-risk patients, there was no procedure-related mortality. CONCLUSION: Our experience suggests that PCPS may be helpful in high risk patients treated with PCI, especially in elective cases. More aggressive and larger scale studies of PCPS should follow

    Limited Feasibility in Endovascular Aneurysm Repair Using Currently Available Graft in Korea

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    Despite the wide acceptance of endovascular aneurysmal repair in patients with abdominal aortic aneurysm (EVAR), stringent morphologic criteria recommended by manufacturers may preclude this treatment in patients with AAA. The purpose of this study was to investigate how many patients are feasible by Zenith and Excluder stent graft system, which are available in Korea. Eighty-two AAA patients (71 men, mean age 70 yr) who had been treated surgically or medically from January 2005 to December 2006 were included. Criteria for morphologic suitability (MS) were examined to focus on characteristics of aneurysm; proximal and distal landing zone; angulation and involvement of both iliac artery aneurysms. Twenty-eight patients (34.1%) were feasible in Zenith stent graft and 31 patients (37.8%) were feasible in Excluder. The patients who were excluded EVAR had an average of 1.61 exclusion criteria. The main reasons for exclusion were an unfavorable proximal neck (n=34, 41.5%) and problem of distal landing zone (n=25, 30.5%). There was no statistical significance among gender, age or aneurysm size in terms of MS. Only 32 patients (39%) who had AAA were estimated to be suitable for two currently approved grafts by strict criteria. However, even unfavorable AAA patients who have severe co-mobidities will be included in EVAR in the near future. Therefore, more efforts including fine skill and anatomical understanding will be needed to meet these challenging cases

    Regulation of mammary gland branching morphogenesis by the extracellular matrix and its remodeling enzymes.

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    A considerable body of research indicates that mammary gland branching morphogenesis is dependent, in part, on the extracellular matrix (ECM), ECM-receptors, such as integrins and other ECM receptors, and ECM-degrading enzymes, including matrix metalloproteinases (MMPs) and their inhibitors, tissue inhibitors of metalloproteinases (TIMPs). There is some evidence that these ECM cues affect one or more of the following processes: cell survival, polarity, proliferation, differentiation, adhesion, and migration. Both three-dimensional culture models and genetic manipulations of the mouse mammary gland have been used to study the signaling pathways that affect these processes. However, the precise mechanisms of ECM-directed mammary morphogenesis are not well understood. Mammary morphogenesis involves epithelial 'invasion' of adipose tissue, a process akin to invasion by breast cancer cells, although the former is a highly regulated developmental process. How these morphogenic pathways are integrated in the normal gland and how they become dysregulated and subverted in the progression of breast cancer also remain largely unanswered questions

    Gene expression and matrix turnover in overused and damaged tendons

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    Chronic, painful conditions affecting tendons, frequently known as tendinopathy, are very common types of sporting injury. The tendon extracellular matrix is substantially altered in tendinopathy, and these changes are thought to precede and underlie the clinical condition. The tendon cell response to repeated minor injuries or “overuse” is thought to be a major factor in the development of tendinopathy. Changes in matrix turnover may also be effected by the cellular response to physical load, altering the balance of matrix turnover and changing the structure and composition of the tendon. Matrix turnover is relatively high in tendons exposed to high mechanical demands, such as the supraspinatus and Achilles, and this is thought to represent either a repair or tissue maintenance function. Metalloproteinases are a large family of enzymes capable of degrading all of the tendon matrix components, and these are thought to play a major role in the degradation of matrix during development, adaptation and repair. It is proposed that some metalloproteinase enzymes are required for the health of the tendon, and others may be damaging, leading to degeneration of the tissue. Further research is required to investigate how these enzyme activities are regulated in tendon and altered in tendinopathy. A profile of all the metalloproteinases expressed and active in healthy and degenerate tendon is required and may lead to the development of new drug therapies for these common and debilitating sports injuries

    Agreement between chromogenic in situ hybridisation (CISH) and FISH in the determination of HER2 status in breast cancer

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    Determination of the HER2/neu (HER2) status in breast carcinoma has become necessary for the selection of breast cancer patients for trastuzumab therapy. Amplification of the gene analysed by fluorescence in situ hybridisation (FISH) or overexpression of the protein determined by immunohistochemistry (IHC) are the two major methods to establish this status. A strong correlation has been previously demonstrated between these two methods. However, FISH is not always feasible in routine practice and weakly positive IHC tumours (2+) do not always correspond to a gene amplification. Our study was performed in order to evaluate the contribution of chromogenic in situ hybridisation (CISH), which enables detection of the gene copies through an immunoperoxidase reaction. CISH was performed in 79 breast carcinomas for which the HER2 status was previously determined by IHC and FISH. The results of IHC, FISH and CISH were compared for each tumour. CISH procedures were successful in 95% of our cases. Whatever the IHC results, we found a very good concordance (96%) between CISH and FISH. Our study confirms that CISH may be an alternative to FISH for the determination of the gene amplification status in 2+ tumours. Our results allow us to think that, in many laboratories, CISH may also be an excellent method to calibrate the IHC procedures or, as a quality control test, to check regularly that the IHC signal is in agreement with the gene statu
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