Safety Aspects of Alumina and Zirconia Ceramics in Hip Surgery

Significant progress towards a fundamental understanding of transformation toughening in composite zirconia ceramics was made possible by the application of a TEM contrast analysis technique for imaging elastic strains. Spherical zirconia particles dispersed in a large-grained alumina matrix were examined by 1 MeV HVEM to simulate bulk conditions. A thermal contraction mismatch arose on cooling from the processing temperature of 1500°C to RT. Tetragonal ZrO2 contracted amisotropically with α(ct) = 16 X 10-6/°C and α(at) = 11 X 10-6/°C and faster than Al2O3 which contracted relatively isotropically at α = 8 X 10-6/°C. A volume increase of +4.9% accompanied the transformation to monoclinic symmetry at room temperature. The elastic strain field surrounding a particle before transformation was 3-dimensionally correlated with the internal crystallographic orientation of the particle and with the strain field after transformation. The aim of this paper is to theoretically and experimentally describe this technique using the ZrO2 as an example and thereby to illustrate the experimental requirements Tor such an analysis in other systems.

Download Full-text

PREPARATION OF DENSE TETRAGONAL ZIRCONIA CERAMICS FROM ZrO2 MICROPOWDERS

Le Journal de Physique Colloques ◽

10.1051/jphyscol:1986135 ◽

1986 ◽

Vol 47 (C1) ◽

pp. C1-237-C1-241

Author(s):

A. SMITH ◽

B. CALES ◽

J. F. BAUMARD

Keyword(s):

Tetragonal Zirconia ◽

Zirconia Ceramics

Download Full-text

Review of operational indications on the design of facilities for radiopharmaceutical manufacturing in italy

Radioprotection ◽

10.1051/radiopro/2020071 ◽

2020 ◽

Author(s):

M.A. D’Avanzo ◽

G.M. Contessa ◽

G. Cocomello ◽

M. Mattozzi ◽

M. Pacilio ◽

...

Keyword(s):

Ionizing Radiation ◽

Design Stage ◽

Safety Aspects ◽

Scientific Institutions ◽

Available Information

Purpose. In this article, the authors propose useful operational indications to approach in the best possible way the issues concerning the design of a facility for manufacturing radiopharmaceuticals, with focus on organizational and safety aspects. Methods. Several documents produced by authoritative bodies, national and international scientific institutions and associations were examined and referenced, to the purpose of reviewing all available information in the field. Results. Indications are gathered for the design stage, including the organization of accesses and routes and characteristics and requirements of premises and systems. Conclusions. Main goal is to guide the reader in evaluating and choosing the most suitable features and equipment to limit the risks due to ionizing radiation and to prevent contamination of the workers and the environment.

Download Full-text

A Comparison of General Anesthesia and Regional Anesthesia as a Risk Factor for Deep Vein Thrombosis Following Hip Surgery: A Critical Review

Thrombosis and Haemostasis ◽

10.1055/s-0038-1647346 ◽

1990 ◽

Vol 64 (04) ◽

pp. 497-500 ◽

Cited By ~ 86

Author(s):

Martin H Prins ◽

Jack Hirsh

Keyword(s):

Deep Vein Thrombosis ◽

General Anesthesia ◽

Regional Anesthesia ◽

Lower Incidence ◽

Hip Surgery ◽

Level Of Evidence ◽

Vein Thrombosis ◽

Postoperative Thrombosis ◽

High Level ◽

Deep Vein

SummaryWe evaluated the evidence in support of the suggestion that the risk of deep vein thrombosis after hip surgery is lower with regional than with general anesthesia. A literature search was performed to retrieve all articles which reported on the incidence of postoperative thrombosis in both fractured and elective hip surgery. Articles were included if the method of anesthesia used was reported and if they used mandatory venography. Based upon the quality of study design the level of evidence provided by a study was graded.In patients who did not receive prophylaxis there were high level studies in elective and fractured hip surgery. All studies showed a statistically significantly lower incidence of postoperative deep vein thrombosis with regional anesthesia (relative risk reductions of 46-55%). There were no direct comparative studies in patients who received prophylaxis. However, between study comparisons did not show even a trend towards to lower incidence of postoperative thrombosis with regional anesthesia.

Download Full-text

Extrinsic Pathway Inhibitor in Elective Surgery: A Comparison with other Coagulation Inhibitors

Thrombosis and Haemostasis ◽

10.1055/s-0038-1651017 ◽

1989 ◽

Vol 62 (03) ◽

pp. 856-860 ◽

Cited By ~ 28

Author(s):

P M Sandset ◽

H E Høgevold ◽

T Lyberg ◽

T R Andersson ◽

U Abildgaard

Keyword(s):

Vascular Surgery ◽

Protein C ◽

Elective Surgery ◽

Perioperative Period ◽

Acute Phase Reactant ◽

Hip Surgery ◽

Albumin Concentration ◽

Extrinsic Pathway ◽

Heparin Cofactor Ii ◽

Coagulation Inhibitors

SummaryExtrinsic coagulation pathway inhibitor may be an important regulator of haemostasis to prevent thrombosis after tissue damage. The functional activity of this inhibitor was determined using a chromogenic substrate assay, and compared to the activities of anti thrombin, heparin cofactor II and protein C during the perioperative period of elective hip replacement (n = 28), cholecystectomy (n = 11), and vascular surgery (n = 5). Peroperatively, all the inhibitors decreased rather similarly and to the same degree as the decrease in albumin concentration. The decreases during hip surgery were about 2-fold the decreases observed during cholecystectomy. A significant peroperative increase in extrinsic pathway inhibitor activity was observed in vascular surgery, probably due to a bolus injection of heparin. Antithrombin, heparin cofactor II and protein C levels normalized on days 3-5 postoperatively in all three patient groups. Sustained low levels of extrinsic pathway inhibitor were observed on postoperative days 1 to 7 in hip surgery patients. Apparently, extrinsic pathway inhibitor is not an acute phase reactant. In uncomplicated surgery, the decreases of the coagulation inhibitor levels are mainly due to hemodilution.

Download Full-text