241 research outputs found

    Positioning of self-assembled Ge islands on stripe-patterned Si (001) substrates

    Full text link
    Self-assembled Ge islands were grown on stripe-patterned Si (001) substrates by solid source molecular beam epitaxy. The surface morphology obtained by atomic force microscopy (AFM) and cross-sectional transmission electron microscopy images (TEM) shows that the Ge islands are preferentially grown at the sidewalls of pure Si stripes along [-110] direction at 650o C or along the trenches, whereas most of the Ge islands are formed on the top terrace when the patterned stripes are covered by a strained GeSi buffer layer. Reducing the growth temperature to 600oC results in a nucleation of Ge islands both on the top terrace and at the sidewall of pure Si stripes. A qualitative analysis, based on the growth kinetics, demonstrates that the step structure of the stripes, the external strain field and the local critical wetting layer thickness for the islands formation contribute to the preferential positioning of Ge islands on the stripes.Comment: 10 pages, 7 figures, 1 table, the original paper is in print in J. Appl. Phy

    Initial stage of the 2D-3D transition of a strained SiGe layer on a pit-patterned Si(001) template

    Full text link
    We investigate the initial stage of the 2D-3D transition of strained Ge layers deposited on pit-patterned Si(001) templates. Within the pits, which assume the shape of inverted, truncated pyramids after optimized growth of a Si buffer layer, the Ge wetting layer develops a complex morphology consisting exclusively of {105} and (001) facets. These results are attributed to a strain-driven step-meandering instability on the facetted side-walls of the pits, and a step-bunching instability at the sharp concave intersections of these facets. Although both instabilities are strain-driven, their coexistence becomes mainly possible by the geometrical restrictions in the pits. It is shown that the morphological transformation of the pit surface into low-energy facets has strong influence on the preferential nucleation of Ge islands at the flat bottom of the pits.Comment: 19 pages, 7 figure

    Cost effectiveness of breast cancer screening and prevention: a systematic review with a focus on risk-adapted strategies

    Get PDF
    OBJECTIVES: Benefit and cost effectiveness of breast cancer screening are still matters of controversy. Risk-adapted strategies are proposed to improve its benefit-harm and cost–benefit relations. Our objective was to perform a systematic review on economic breast cancer models evaluating primary and secondary prevention strategies in the European health care setting, with specific focus on model results, model characteristics, and risk-adapted strategies. METHODS: Literature databases were systematically searched for economic breast cancer models evaluating the cost effectiveness of breast cancer screening and prevention strategies in the European health care context. Characteristics, methodological details and results of the identified studies are reported in evidence tables. Economic model outputs are standardized to achieve comparable cost-effectiveness ratios. RESULTS: Thirty-two economic evaluations of breast cancer screening and seven evaluations of primary breast cancer prevention were included. Five screening studies and none of the prevention studies considered risk-adapted strategies. Studies differed in methodologic features. Only about half of the screening studies modeled overdiagnosis-related harms, most often indirectly and without reporting their magnitude. All models predict gains in life expectancy and/or quality-adjusted life expectancy at acceptable costs. However, risk-adapted screening was shown to be more effective and efficient than conventional screening. CONCLUSIONS: Economic models suggest that breast cancer screening and prevention are cost effective in the European setting. All screening models predict gains in life expectancy, which has not yet been confirmed by trials. European models evaluating risk-adapted screening strategies are rare, but suggest that risk-adapted screening is more effective and efficient than conventional screening

    Interventional Cardiology in Europe 1993

    Get PDF
    An annual survey on cardiac interventions in Europe is performed by the working group on Coronary Circulation of the European Society of Cardiology with the help of the national societies of cardiology. A questionnaire about cardiac interventions in 1993 was mailed to a representative of the national societies of 35 members of the European Society of Cardiology. The data collection of coronary interventions was delayed by slow backreporting and from 10 of the 35 national members data were missing or grossly incomplete. They were excluded from the analysis. Coronary anglography A total of 756 822 coronary angiograms were reported resulting in an incidence of 1146 ± 1024 per 106 inhabitants, ranging from 24 (Romania) to 3499 (Germany). This represents an increase of 12% compared to 1992. Germany (279 882 cases), France (157 237), the United Kingdom (77 000), Italy (44 934) and Spain (37 591) registered 79% of all the coronary angiograms performed. Percutaneous transluminal coronary angioptasty A total of 183 728 percutaneous transluminal coronary angioplasty cases were reported in 1993, 24% more than in 1992. On average, they accounted for 18 ± 7% (range 8 (Romania) to 35% (Sweden)) of the coronary angiograms. Most of these percutaneous transluminal coronary angioplasties (82%) were confined to a single vessel. In 13% only, percutaneous transluminal coronary angioplasty took place immediately after the diagnostic study. Adjusted per capita, Germany ranks first with 873 percutaneous transluminal coronary angioplasties per 106 inhabitants, followed by France (737), Holland (725), Belgium (713), and Switzerland (665). The European mean of percutaneous transluminal coronary angioplasties per 106 inhabitants was 270 ± 279, representing an increase of 14% compared with 1992. A major in-hospital complication was reported in 3.8% of the patients undergoing percutaneous transluminal coronary angioplasty: 0.6% hospital deaths, 1.5% emergency coronary artery bypass graftings, and 1.7% myocardial infarctions. New devices In 1993 stents were implanted in 6444 patients (3.5% of all percutaneous transluminal coronary angioplasty patients), equally distributed between bail-out situations (53%) and elective procedures. The 14 stent implanting countries showed a mean increase in the incidence of coronary stenting of 53% compared with 1992. Other interventional devices were applied in 7045 cases, i.e. 3.8% of all percutaneous transluminal coronary angioplasty cases. Coronary ultrasound (2194 cases) and coronary angioscopy (380 cases) were performed infrequently. Non-coronary interventions Valvuloplasties were the most frequently performed non-coronary interventions. Six European countries performed more than 300 valvuloplasties each in 1993. Most of them were mitral valvuloplasties in southern countries. Conclusions Although partial backreporting might bias conclusions, several findings of this survey are noteworthy for the participating countries: The number of percutaneous transluminal coronary angioplasties is universally increasing. There is an extremely wide range of coronary angiography and percutaneous transluminal coronary angioplasties performed per population. The most common additional procedure is a stent implantation while other new devices are only rarely applied. Mitral valvuloplasty is the most frequently performed non-coronary intervention. (Eur Heart J 1996; 17: 1318-1328

    Psychotherapy in Europe

    Get PDF
    Psychotherapy was an invention of European modernity, but as the 20th century unfolded, and we trace how it crossed national and continental borders, its goals and the particular techniques by which it operated become harder to pin down. This introduction briefly draws together the historical literature on psychotherapy in Europe, asking comparative questions about the role of location and culture, and networks of transmission and transformation. It introduces the six articles in this special issue on Greece, Hungary, Yugoslavia, Russia, Britain and Sweden as well as its parallel special issue of History of Psychology on ‘Psychotherapy in the Americas’. It traces what these articles tell us about how therapeutic developments were entangled with the dramatic, and often traumatic, political events across the continent: in the wake of the Second World War, the emergence of Communist and authoritarian regimes, the establishment of welfare states and the advance of neoliberalism

    Koliko su studenti više medicinske škole u Bitoli upoznati s problemom infekcije HCV-om

    Get PDF
    Healthcare workers are at risk of occupationally-acquired viral infections such as human immunodefi ciency virus (HIV), hepatitis B (HBV), and hepatitis C (HCV). HCV is parenterally transmitted and has been found in every part of the world. This cross-sectional study was conducted to establish the awareness and attitude about HCV infections among 210 full-time and part-time nursing students of the Medical College in Bitola, Macedonia ‘from May to June 2009. For this purpose we used a self-administered questionnaire which consisted of three parts. The fi rst included demographic data, the second included questions about causes of infection, mode of transmission, symptoms, acute and chronic hepatitis, and prevention, and the third questions about students’ attitude toward patients with suspect or confi rmed HCV infection. Full-time students showed higher HCV awareness (84 %) than part-time students (69 %). 58 % of the full-time and 79 % of the part-time students said they would not avoid professional contact with suspect or HCV infected patients. Our study has shown that even though both groups of students have a suffi cient knowledge about HCV to face future challenges, they need further education on the subject. Practical recommendations would help to reduce stigmatising behaviour still further.Zdravstveni su radnici izloženi profesionalnomu riziku od infekcije virusom humane imunodefi cijencije (HIV-om), hepatitis B virusom (HBV-om) te hepatitis C virusom (HCV-om). HCV se prenosi parenteralno i ima ga posvuda u svijetu. Ovo smo presječno ispitivanje proveli da utvrdimo koliko su studenti za medicinske tehničare i sestre upoznati s infekcijom HCV-om i saznamo njihove stavove o tome. Ispitivanje je obuhvatilo 210 redovitih i izvanrednih studenata Visoke medicinske škole u Bitoli i trajalo je od svibnja do lipnja 2009. Za ispitivanje je rabljen opširan upitnik. Odgovori su pokazali da redoviti studenti imaju bolji uvid u predmet (s 84 % točnih odgovora) od izvanrednih studenata (69 %). U pogledu stava prema pacijentima 58 % redovitih i 79 % izvanrednih studenata ne izbjegava dodir s pacijentima koji su infi cirani HCV-om. Ispitivanje je pokazalo da su studenti iz obje skupine dovoljno upoznati s infekcijom HCV-om, rizičnim čimbenicima i načinom prijenosa, ali je potrebno to znanje nadograditi

    Epidemiology and Clinical Features of Imported Dengue Fever in Europe: Sentinel Surveillance Data from TropNetEurop

    Get PDF
    Travelers have the potential both to acquire and to spread dengue virus infection. The incidence of dengue fever (DF) among European travelers certainly is underestimated, because few centers use standardized diagnostic procedures for febrile patients. In addition, DF is currently not reported in most European public health systems. Surveillance has commenced within the framework of a European Network on Imported Infectious Disease Surveillance (TropNetEurop) to gain information on the quantity and severity of cases of dengue imported into Europe. Descriptions of 294 patients with DF were analyzed for epidemiological information and clinical features. By far the most infections were imported from Asia, which suggests a high risk of DF for travelers to that region. Dengue hemorrhagic fever occurred in 7 patients (2.4%) all of whom recovered. Data reported by member sites of the TropNetEurop can contribute to understanding the epidemiology and clinical characteristics of imported D

    Age as a Risk Factor for Severe Manifestations and Fatal Outcome of Falciparum Malaria in European Patients: Observations from TropNetEurop and SIMPID Surveillance Data

    Get PDF
    Previous studies have indicated that age is a risk factor for severe falciparum malaria in nonimmune patients. The objectives of this study were to reevaluate previous findings with a larger sample and to find out how strongly clinical outcomes for elderly patients differ from those for younger patients. Results of adjusted analyses indicated that the risks of death due to falciparum malaria, of experiencing cerebral or severe disease in general, and of hospitalization increased significantly with each decade of life. The case-fatality rate was almost 6 times greater among elderly patients than among younger patients, and cerebral complications occurred 3 times more often among elderly patients. Antimalarial chemoprophylaxis was significantly associated with a lower case-fatality rate and a lower frequency of cerebral complications. Women were more susceptible to cerebral complications than were men. Our study provides evidence that falciparum malaria is more serious in older patients and demonstrates that clinical surveillance networks are capable of providing quality data for investigation of rare events or disease

    Epidemiology and clinical features of vivax malaria imported to Europe: Sentinel surveillance data from TropNetEurop

    Get PDF
    BACKGROUND: Plasmodium vivax is the second most common species among malaria patients diagnosed in Europe, but epidemiological and clinical data on imported P. vivax malaria are limited. The TropNetEurop surveillance network has monitored the importation of vivax malaria into Europe since 1999. OBJECTIVES: To present epidemiological and clinical data on imported P. vivax malaria collected at European level. MATERIAL AND METHODS: Data of primary cases of P. vivax malaria reported between January 1999 and September 2003 were analysed, focusing on disease frequency, patient characteristics, place of infection, course of disease, treatment and differences between network-member countries. RESULTS: Within the surveillance period 4,801 cases of imported malaria were reported. 618 (12.9%) were attributed to P. vivax. European travellers and immigrants were the largest patient groups, but their proportion varied among the reporting countries. The main regions of infection in descending order were the Indian subcontinent, Indonesia, South America and Western and Eastern Africa, as a group accounting for more than 60% of the cases. Regular use of malaria chemoprophylaxis was reported by 118 patients. With 86 (inter-quartile range 41–158) versus 31 days (inter-quartile range 4–133) the median symptom onset was significantly delayed in patients with chemoprophylaxis (p < 0.0001). Common complaints were fever, headache, fatigue, and musculo-skeletal symptoms. All patients survived and severe clinical complications were rare. Hospitalization was provided for 60% and primaquine treatment administered to 83.8% of the patients, but frequencies varied strongly among reporting countries. CONCLUSIONS: TropNetEurop data can contribute to the harmonization of European treatment policies
    corecore