The dynamic impedance of a sphere oscillating in an elastic medium is
considered. Oestreicher's formula for the impedance of a sphere bonded to the
surrounding medium can be expressed simply in terms of three lumped impedances
associated with the displaced mass and the longitudinal and transverse waves.
If the surface of the sphere slips while the normal velocity remains
continuous, the impedance formula is modified by adjusting the definition of
the transverse impedance to include the interfacial impedance.Comment: 10 pages, 2 figure

Baigent, C

Collins, R

Peto, R

Sudlow, C

English

arXiv

Andrew N. Norris

von Gierke H. E.

Abramowitz M.

Stokes G. G.

Crossref

Impedance of a sphere oscillating in an elastic medium with and without slip

MUCC (Crossref)

Objective To determine the effects of antiplatelet therapy among patients at high risk of occlusive vascular events.Design Collaborative meta-analyses (systematic overviews).Inclusion criteria Randomised trials of an antiplatelet regimen versus control or of one antiplatelet regimen versus another in high risk patients (with acute or previous vascular disease or some other predisposing condition) from which results were available before September 1997. Trials had to use a method of randomisation that precluded prior knowledge of the next treatment to be allocated and comparisons had to be unconfounded-that is, have study groups that differed only in terms of antiplatelet regimen.Studies reviewed 287 studies involving 135 000 patients in comparisons of antiplatelet therapy versus control and 77 000 in comparisons of different antiplatelet regimens.Main outcome measure "Serious vascular event": non-fatal myocardial infarction, non-fatal stroke, or vascular death.Results Overall, among these High risk patients, allocation to antiplatelet therapy reduced the combined outcome of any serious vascular event by about one quarter; non-fatal myocardial infarction was reduced by one third, non-fatal stroke by one quarter, and vascular mortality by one sixth (with no apparent adverse effect on other deaths). Absolute reductions in the risk of having a serious vascular event were 36 (SE 5) per 1000 treated for two years among patients with previous myocardial infarction; 38 (5) per 1000 patients treated for one month among patients with acute myocardial infarction; 36 (6) per 1000 treated for two years among those with previous stroke or transient ischaemic attack; 9 (3) per 1000 treated for three weeks among those with acute stroke; and 22 (3) per 1000 treated for two years among other high risk patients (with separately significant results for those with stable angina (P=0.0005), peripheral arterial disease (P=0.004), and atrial fibrillation (P=0.01)). In each of these high risk categories, the absolute benefits substantially outweighed the absolute risks of major extracranial bleeding. Aspirin was the most widely studied antiplatelet drug, with doses of 75-150 mg daily at least as effective as higher daily doses. The effects of doses lower than 75 mg daily were less certain. Clopidogrel reduced serious vascular events by 10% (4%) compared with aspirin, which was similar to the 12% (7%) reduction observed with its analogue ticlopidine. Addition of dipyridamole to aspirin produced no significant further reduction in vascular events compared with aspirin alone. Among patients at high risk of immediate coronary occlusion, short term addition of an intravenous glycoprotein IIb/IIIa antagonist to aspirin prevented a further 20 (4) vascular events per 1000 (P &lt;0.0001) but caused 23 major (but rarely fatal) extracranial bleeds per 1000.Conclusions Aspirin (or another oral antiplatelet drug) is protective in most types of patient at increased risk of occlusive vascular events, including those with an acute myocardial infarction or ischaemic stroke, unstable or stable angina, previous myocardial infarction, stroke or cerebral ischaemia, peripheral arterial disease, or atrial fibrillation, Low dose aspirin (75-150 mg daily) is an effective antiplatelet regimen for long term use, but in acute settings an initial loading dose of at least 150 mg aspirin may be required. Adding a second antiplatelet drug to aspirin may produce additional benefits in some clinical circumstances, but more research into this strategy is needed.</p

ARTS repository - University of Groningen

Collaborative meta-analysis of randomised trials of antiplatelet therapy for prevention of death, myocardial infarction, and stroke in high risk patients

Mccollum, Charles

McCollum, CN

Collaboration, Antithrombotic Trialists'

The University of Manchester - Institutional Repository

Objective: To determine the effects of antiplatelet therapy among patients at high risk of occlusive vascular events. Design: Collaborative meta-analyses (systematic overviews). Inclusion criteria: Randomised trials of an antiplatelet regimen versus control or of one antiplatelet regimen versus another in high risk patients (with acute or previous vascular disease or some other predisposing condition) from which results were available before September 1997. Trials had to use a method of randomisation that precluded prior knowledge of the next treatment to be allocated and comparisons had to be unconfounded-that is, have study groups that differed only in terms of antiplatelet regimen. Studies reviewed: 287 studies involving 135 000 patients in comparisons of antiplatelet therapy versus control and 77 000 in comparisons of different antiplatelet regimens. Main outcome measure: "Serious vascular event": non-fatal myocardial infarction, non-fatal stroke, or vascular death. Results: Overall, among these high risk patients, allocation to antiplatelet therapy reduced the combined outcome of any serious vascular event by about one quarter; non-fatal myocardial infarction was reduced by one third, non-fatal stroke by one quarter, and vascular mortality by one sixth (with no apparent adverse effect on other deaths). Absolute reductions in the risk of having a serious vascular event were 36 (SE 5) per 1000 treated for two years among patients with previous myocardial infarction; 38 (5) per 1000 patients treated for one month among patients with acute myocardial infarction; 36 (6) per 1000 treated for two years among those with previous stroke or transient ischaemic attack; 9 (3) per 1000 treated for three weeks among those with acute stroke; and 22 (3) per 1000 treated for two years among other high risk patients (with separately significant results for those with stable angina (P=0.0005), peripheral arterial disease (P=0.004), and atrial fibrillation (P=0.01)). In each of these high risk categories, the absolute benefits substantially outweighed the absolute risks of major extracranial bleeding. Aspirin was the most widely studied antiplatelet drug, with doses of 75-150 mg daily at least as effective as higher daily doses. The effects of doses lower than 75 mg daily were less certain. Clopidogrel reduced serious vascular events by 10% (4%) compared with aspirin, which was similar to the 12% (7%) reduction observed with its analogue ticlopidine. Addition of dipyridamole to aspirin produced no significant further reduction in vascular events compared with aspirin alone. Among patients at high risk of immediate coronary occlusion, short term addition of an intravenous glycoprotein IIb/IIIa antagonist to aspirin prevented a further 20 (4) vascular events per 1000 (P<0.0001) but caused 23 major (but rarely fatal) extracranial bleeds per 1000. Conclusions: Aspirin (or another oral antiplatelet drug) is protective in most types of patient at increased risk of occlusive vascular events, including those with an acute myocardial infarction or ischaemic stroke, unstable or stable angina, previous myocardial infarction, stroke or cerebral ischaemia, peripheral arterial disease, or atrial fibrillation. Low dose aspirin (75-150 mg daily) is an effective antiplatelet regimen for long term use, but in acute settings an initial loading dose of at least 150 mg aspirin may be required. Adding a second antiplatelet drug to aspirin may produce additional benefits in some clinical circumstances, but more research into this strategy is needed

Antithrombotic Trialists' Collaboration

M. Catalano

AIR Universita degli studi di Milano

OBJECTIVE: To determine the effects of antiplatelet therapy among patients at high risk of occlusive vascular events. DESIGN: Collaborative meta-analyses (systematic overviews). INCLUSION CRITERIA: Randomised trials of an antiplatelet regimen versus control or of one antiplatelet regimen versus another in high risk patients (with acute or previous vascular disease or some other predisposing condition) from which results were available before September 1997. Trials had to use a method of randomisation that precluded prior knowledge of the next treatment to be allocated and comparisons had to be unconfounded-that is, have study groups that differed only in terms of antiplatelet regimen. STUDIES REVIEWED: 287 studies involving 135 000 patients in comparisons of antiplatelet therapy versus control and 77 000 in comparisons of different antiplatelet regimens. MAIN OUTCOME MEASURE: "Serious vascular event": non-fatal myocardial infarction, non-fatal stroke, or vascular death. RESULTS: Overall, among these high risk patients, allocation to antiplatelet therapy reduced the combined outcome of any serious vascular event by about one quarter; non-fatal myocardial infarction was reduced by one third, non-fatal stroke by one quarter, and vascular mortality by one sixth (with no apparent adverse effect on other deaths). Absolute reductions in the risk of having a serious vascular event were 36 (SE 5) per 1000 treated for two years among patients with previous myocardial infarction; 38 (5) per 1000 patients treated for one month among patients with acute myocardial infarction; 36 (6) per 1000 treated for two years among those with previous stroke or transient ischaemic attack; 9 (3) per 1000 treated for three weeks among those with acute stroke; and 22 (3) per 1000 treated for two years among other high risk patients (with separately significant results for those with stable angina (P=0.0005), peripheral arterial disease (P=0.004), and atrial fibrillation (P=0.01)). In each of these high risk categories, the absolute benefits substantially outweighed the absolute risks of major extracranial bleeding. Aspirin was the most widely studied antiplatelet drug, with doses of 75-150 mg daily at least as effective as higher daily doses. The effects of doses lower than 75 mg daily were less certain. Clopidogrel reduced serious vascular events by 10% (4%) compared with aspirin, which was similar to the 12% (7%) reduction observed with its analogue ticlopidine. Addition of dipyridamole to aspirin produced no significant further reduction in vascular events compared with aspirin alone. Among patients at high risk of immediate coronary occlusion, short term addition of an intravenous glycoprotein IIb/IIIa antagonist to aspirin prevented a further 20 (4) vascular events per 1000 (P<0.0001) but caused 23 major (but rarely fatal) extracranial bleeds per 1000. CONCLUSIONS: Aspirin (or another oral antiplatelet drug) is protective in most types of patient at increased risk of occlusive vascular events, including those with an acute myocardial infarction or ischaemic stroke, unstable or stable angina, previous myocardial infarction, stroke or cerebral ischaemia, peripheral arterial disease, or atrial fibrillation. Low dose aspirin (75-150 mg daily) is an effective antiplatelet regimen for long term use, but in acute settings an initial loading dose of at least 150 mg aspirin may be required. Adding a second antiplatelet drug to aspirin may produce additional benefits in some clinical circumstances, but more research into this strategy is needed

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A: Hormone replacement therapy and cardiovascular disease. Br Med Bull

and Drug Administration: The estrogen and progestin dilemma: new advice, labelling guidelines.

AT: Estrogens, the immune response and autoimmunity. Clin Exp Rheumatology

C: A prospective study of estrogen replacement therapy and the risk of developing Alzheimer's disease. The Baltimore Longitudinal Study of Aging. Neurology

Cauley JA: Association of estrogen replacement therapy with the risk of osteoarthritis of the hip in elderly white women. Arch Intern Med

Climacteric

Colditz GA: Estrogen replacement therapy and coronary heart disease: a quantitative assessment of the epidemiological evidence. Prev Med

Collaborative Group on Hormonal Factors in Breast Cancer: Breast cancer and hormone replacement therapy: collaborative reanalysis of data from 51 epidemiological studies of 52 705 women with breast cancer and 108 411 women without breast cancer. Lancet

Committee on Safety of Medicines: HRT:update on the risk of breast cancer and long term safety. Current Problems in Pharmacovigilanc

Council's General Practice Research Framework: Randomised comparison of oestrogen versus oestrogen plus progestogen hormone replacement therapy in women with hysterectomy. BMJ

Effect of oestrogen during menopause on risk and age at outset of Alzheimer's disease. Lancet

Effects of estrogen use on lens transmittance in postmenopausal women. Ophthamology

Estrogen replacement therapy and risk of epithelial ovarian cancer. Gynecol Oncol

EUROQOL: A new facility for the measurement of health related quality of life. Health Policy

for the Women's Health Initiative Investigators: Risks and benefits of estrogen plus progestin in healthy postmenopausal women. Principal results from the Women's Health Initiative randomized controlled trial. JAMA

for the Womens Health Initiative investigators: Effects of estrogen plus progestin on health related quality of life.

Goldar D: Effect of progestin therapy on cortical and trabecular bone: comparison with estrogen.

Health-related behaviours and their correlates in a general population sample of 45-year old women. Psychology and Health

Hennekens CH, Speizer FE: Postmenopausal hormone therapy and mortality.

Hennekens CH: Postmenopausal estrogen therapy and cardiovascular disease: Ten year follow-up from the Nurses' Health Study.

Hennekens CH: Prospective study of exogenous hormones and risk of pulmonary embolism in women. Lancet

Hip fracture and the use of estrogens in postmenopausal women. The Framingham Study.

Hormone replacement therapy and breast cancer: an overview.

Horwitz RI: A clinical trial of estrogen -replacement therapy after ischemic stroke.

Howe GR: Menopausal hormone use and colorectal cancer in Saskatchewan: a record linkage cohort study. Cancer Epidemiology, Biomarkers & Prevention

Jr: Reduced mortality associated with long-term postmenopausal estrogen therapy. Obstet Gynecol

KD: The association between estrogen status and alveolar bone density changes in postmenopausal women with a history of periodontitis. Periodontology

KM: Risk of hospital admission for idiopathic venous thromboembolism among users of postmenopausal oestrogens. Lancet

Knapp RC: Review of epidemiologic studies of endometrial cancer and exogenous estrogen. Obstet Gynecol

L: Validation study of WOMAC: a health ststus instrument for measuring clinically important patient relevant outcomes to antirheumatic drug therapy in patients with osteoarthritis of the hip or knee. The Journal of Rheumatology

LL: Are sex hormones associated with age-related maculopathy in women? The Beaver Dam Eye Study. Trans Am Ophthalmol Soc

MacDermid JC: Clinimetric properties of the AUSCAN Osteoarthritis Hand Index: an evaluation of reliability, validity and responsiveness. Osteoarthritis Cartilage

MM: Case control study of venous thromboembolism risk in users of hormone replacement therapy. Lancet

Modelling Survival Data in Medical Research Chapman and Hall;

Mortality associated with hormone replacement therapy in younger and older women.

Oliart AD: Hormone replacement therapy and risk of venous thromboembolism: population based case-control study. BMJ

Parazzini F: Oral contraceptives, hormone replacement therapy and risk of colorectal cancer.

Prevalence of Dementia in Users of Hormone Replacement Therapy as Defined by Prescription.

Randomised controlled trials and retrospective controls. BMJ

S: Risk of venous thromboembolism in users of hormone replacement therapy. Lancet

Sandset PM: Increased risk of recurrent venous thromboembolism during hormone replacement therapy. Results of the randomized, double-blind, placebo-controlled estrogen in venous thromboembolism trial (EVTET). Thrombosis and Haemostasis

SC: Development of a new type of global quality of life scale, and comparison of performance and preference for 12 global scales. Quality of Life Research

Sherbourne C: The MOS 36-item short-form health survey (SF 36). 1. Conceptual framework and item selection. Medical Care

Spinato S: Efficacy of hormone replacement therapy in postmenopausal women with oral discomfort. Oral Surgery, Oral Medicine, Oral Pathology

SR: Hormone therapy to prevent disease and prolong life in postmenopausal women. Ann Intern Med

Stampfer MJ: A prospective, observational study of postmenopausal hormone therapy and primary prevention of cardiovascular disease. Ann Intern Med

Stampfer MJ: Postmenopausal hormone use and secondary prevention of coronary events in the Nurses' Health Study: a prospective, observational study. Ann Intern Med

Study collaborators: Breast cancer and hormone-replacement therapy in the Million Women Study. Lancet

Sudden sensorineural deafness and hormone replacement therapy.

The Benefits of Estrogen Replacement Therapy on Oral Health. Arch Int Med

The CES-D Scale: A self-report depression scale for research in the general population. Applied Psychological Measurement

The European Agency for the Evaluation of Medical Products: EMEA public statement on recent publications regarding hormone replacement therapy. [http://www.emea.europa.eu/pdfs/human/ press/pus/3306503en.pdf]. 3

The incidence and natural history of knee osteoarthritis in the elderly. The Framingham Osteoarthritis Study. Arthritis Rheum

The MRC long-term randomised controlled trial of hormone replacement therapy: Background, design and objectives.

The Women's Health Initiative Study Group: Design of the Women's Health Initiative Clinical trial and Observational Study. Controlled Clinical Trials

The women's health questionnaire: A measure of mid-aged women's perceptions of their emotional and physical health. Psychology and Health

The Writing Group for the PEPI trial: Effects of estrogen/progestin regimens on heart disease risk factors in postmenopausal women.

TW: Hormone replacement therapy in general practice: a survey of doctors in the MRC's general practice research framework. BMJ

WISDOM: history and early demise – was it inevitable? Climacteric

Women's Health Initiative Steering Committee: Effects of conjugated equine estrogen in postmenopausal women with hysterectomy. The Women's Health Initiative Randomised Controlled Trial. JAMA

Collaborative meta-analysis of randomised trials of antiplatelet therapy for prevention of death, myocardial infarction, and stroke in high risk patients.

https://air.unimi.it/retrieve/handle/2434/59632/153855/71.full.pdf

Impedance of a sphere oscillating in an elastic medium with and without
  slip

Impedance of a sphere oscillating in an elastic medium with and without slip

Abstract

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MUCC (Crossref)

ARTS repository - University of Groningen

The University of Manchester - Institutional Repository

AIR Universita degli studi di Milano

ARTS repository - University of Groningen

MUCC (Crossref)

LSHTM Research Online