PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Materials Testing”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 829 records · Page 46Linked to original sources
PubMed1981

Closure of the abdominal wound with single-layer and double-layer technique. Animal studies.

An experimental investigation on rabbits was designed to determine which closure technique, single-layer or double-layer, gave the most secure closure of abdominal wall wounds. Interrupt Prolene sutures size 6-0 were used, and the wounds were tested mechanically in a materials testing machine on the 6th, 15th and 56th day after wounding. The results showed that the double-layer closed wound had, when tested after removal of sutures, a greater strength and higher energy absorption compared to the single-layer closed wound, which however had, when tested with sutures in situ, greater strength and higher energy absorption in the early post-operative phase. The possible explanations of these observations are discussed. Extrapolating from the animal experiments to the clinical situation, it can be concluded, that the double-layer technique was not to be preferred to the single-layer technique when securing a wound against rupture.

Abdominal Muscles↗
PubMed1982

Ski standards developed by the American Society for Testing and Materials.

Although it is not a glamorous or financially rewarding activity, the work of writing standards has been of benefit to the entire skiing community. The benefit or contribution of any particular standard varies, but the overall benefit of standards is real. The sport is safer and the responsibilities of various segments are clearer because of the efforts of the standard writers.

Equipment Design↗
PubMed1993

[Effect of the storage temperature and time and the test sample materials on the LDH isoenzyme activity and protein fractions in horse blood].

The LDH-isoenzyme activities and the concentration of protein fractions did not differ among heparinized plasma and serum samples of horses. In heparinized plasma samples stored at 20-22 degrees C and -18 degrees C the LDH-isoenzyme activities and the content of the protein fractions remained constant within seven days. In contrast in heparinized blood samples the total LDH activity increased markedly after seven days of storage. This increase was shared by all LDH-isoenzymes but to different extents. While the share of LDH1, LDH2 and LDH3 decreased, the proportions of LDH4 and LDH5 increased. The concentration of the protein fractions in heparinized blood samples was not affected by storage at 20-22 degrees C for seven days.

Animals↗
PubMed1997

[Elimination of nitrogen dioxide and nitric oxide by soda lime and its components].

OBJECTIVES: To investigated the efficacy of soda lime and its components in absorbing NO2 and NO. METHODS: VIP BIRD ventilator was connected with Siemens test lung. While the concentration of inhaled NO was 80 mg/L, the inspired gas passed through soda lime or its component. NO and NO2 were measured before and after testing materials in the circuit. Test 1, the soda lime canister sequentially was filled with smaller particle soda lime 500, 250, 125, 62.5, 39, 20, 10 and 0 g, to determine weight-efficacy relationship of the soda lime. Test 2, the canister sequentially was filled with bigger particle soda lime 500, 62.5, 30, 20 and 10 g, for comparing effective absorption of NO and NO2 between the two types of soda lime Test 3, 1.0 g methyl orange was added to smaller particle soda lime 10 g and 20 g respectively to observe its effect on eliminating NO and NO2. Test 4, silica gel tube was filled with smaller particle soda lime 10 g, KOH 10 g, NaOH 10 g, Ca(OH)2 2.5 g, and methly orange 0.5 g respectively for observing their ability of eliminating NO and NO2. RESULTS: The two types soda lime had the ability to eliminating NO and NO2 from inspired gas with a positive relationship with its weight. Both KOH and NaOH did not eliminate NO and NO2 Ca(OH)2 and methyl orange had a week ability. Methyl orange did not affect the ability of soda lime to eliminate NO2, but decreased its ability to eliminate NO. During 240 min, the eliminating NO2 ability of soda lime did not change, but the eliminating NO ability was reduced from 30% to 19% after 60 min. CONCLUSIONS: The effective components to eliminate NO and NO2 in soda lime are Ca(OH)2 and NaOH. Their ability to eliminate NO and NO2 increases with increase in their weight. The ability to eliminate NO decreases with increase in the contacting time with NO.

Calcium Compounds↗
PubMed2003

Two-body and three-body wear of glass ionomer cements.

OBJECTIVES: Glass ionomer cements (GIC) have been modified in an attempt to improve their mechanical properties. The objective of the present paper was to compare the two-body and three-body wear of four modified GIC. The tested materials were Fuji IX (GC Corporation), Hi-Fi (Shofu) and Ketac Molar Aplicap (3M/ESPE). The cermet cement Ketac Silver Maxicap (3M/ESPE) was used as reference material. METHODS: Two-body wear tests were carried out in the computer controlled 'artificial mouth' of the Munich Dental School, three-body wear was tested with the ACTA wear machine. RESULTS: The resulting average two-body wear rates (in microm) were: Fuji IX 327 (SD +/- 82) < Ketac Molar 379 (SD +/- 94) < Hi-Fi 376 (SD +/- 90) < Ketac silver 449 (SD +/- 127). The differences between the materials were significant (P < 0.05, ANOVA, modified LSD-test) with the exception of Ketac Molar and Hi-Fi. The average three-body wear rates (in microm) were: Hi-Fi 30 (SD +/- 10) < Ketac Molar +/- 42 (SD +/- 12) < Fuji IX 49 (SD +/- 14) < Ketac silver 73 (SD +/- 23). The difference between Ketac silver and the three other materials was significant (P < 0.05, ANOVA, modified LSD-test). No significant difference was calculated between Hi-Fi, Ketac Molar and Fuji IX. CONCLUSIONS: As Ketac Molar, Hi-Fi and Fuji IX show better wear resistance compared to Ketac silver both in occlusal-contact and contact-free areas, it may be assumed that the wear resistance of a glass ionomer cement may be improved more by changing the powder: liquid ratio than by incorporating silver particles into the glass powder.

Analysis of Variance↗
PubMed1960

The toxicity of rubbers and plastics used in transfusion-giving sets.

The toxicity of different rubbers and plastics used in transfusion-giving sets has been investigated by examining their effects on (a) cultures of chick embryo tissues, (b) the oxygen uptake of guinea-pig skin tissue cultures, and (c) the growth of Str. pyogenes. The results of the laboratory tests have been compared with the incidence of thrombophlebitis after prolonged transfusions through the various materials. It was found that where the materials inhibited the growth of Str. pyogenes they were also toxic to tissue cultures, but that some materials which were toxic to tissue cultures did not inhibit bacterial growth. The assessments of the relative toxicity of the materials tested by the two tissue culture methods were in agreement. The skin respiration studies, however, gave more information on the early effects of the toxic materials. The relative toxicity of the materials as revealed by these tests could be correlated with the differences in the incidence of thrombophlebitis following intravenous infusions administered through giving-sets assembled with the materials tested. It is suggested therefore that the toxicity revealed by these tests is of clinical importance, and that tissue culture toxicity tests will prove to be of value in selecting rubbers and plastics for clinical purposes.

Blood Transfusion↗
PubMed2000

Cytotoxicity evaluation of perforation repair materials on human periodontal ligament cells in vitro.

Perforation of a tooth structure resulting in communication of the pulp space with periodontium occasionally occurs during endodontic therapy. For the best prognosis, the perforation area must be sealed as soon as possible. Because these materials will be in direct contact with periodontal tissues, their cytotoxic potential must be evaluated before clinical use. The purpose of this study was to determine the cytocompatibility of three perforation repair materials (amalgam, resin, and glass ionomer). Cultured human periodontal ligament (PDL) cells were used to evaluate the cellular response resulting from these materials by cell viability and proliferation assays. Twenty-seven 5 x 4 mm cylinders of each material were fabricated for this study. All tested materials were cytotoxic to human PDL cells. Both types of material and time affected cell viability and proliferation. Resin exhibited the most cytotoxic effects followed by glass ionomer and amalgam during a 14-day incubation period. Amalgam and glass ionomer slightly inhibited cell viability and growth in the first 24 hr, compared with the control. Amalgam or glass ionomer may initially react more favorably to PDL cells than resin. The present model of cultured human PDL cells is simple, relatively cheap, and easily established and propagated under standardized conditions in any laboratory. Furthermore, this method allows long-term observation of human cellular reactions and thus might be a preliminary screening test for initial biocompatibility of dental materials.

Analysis of Variance↗
PubMed1989

[A dynamic fitness test and a new method to measure the thickness of film using the digital subtraction system of X-ray photographic density].

It is impossible to show the dynamic fitness conditions of a denture base using White Silicone or other fitness test materials. In the present paper, materials and the measuring method for the dynamic fitness test were investigated. In order to choose the suitable materials for the dynamic fitness test, various kinds of ready made materials, such as wax or dynamic impression materials, were examined by load test and investigated the change on standing of flow character. EXPERIMENTAL WAX was made for dynamic fitness test, and was examined by load test and clinical test. EXPERIMENTAL WAX consists of DISCLOSING WAX (KERR), as a basic material, and the contrast medium. Extending the system of the conventional measuring method for White Silicone, DIGITAL SUBTRACTION SYSTEM (DSS) was developed as a new method of quantitative analysis for the thickness of wax film. In this system, thickness of wax film is measured from the X-ray photographic density and it's digital subtraction management. Accuracy of this system was also investigated. The summary of results is shown below. 1. It became evident that ready made materials had no useful characters for the dynamic fitness test. 2. EXPERIMENTAL WAX showed similar load effects with White Silicone when the load was 5 or 10kg. 3. Dynamic fitness and the mobility of the denture base during function were able to be shown by EXPERIMENTAL WAX, but it's operation was more complicated than White Silicone. 4. DIGITAL SUBTRACTION SYSTEM (DSS), a new method of quantitative analysis for the thickness of wax film, was developed. 5. Resolving power and measuring range of DSS were effected by quantity of subtraction. 6. DSS is not only useful to measure the thickness of EXPERIMENTAL WAX, but also has wide applications.

Dental Stress Analysis↗
PubMed2003

Development of a modified medium pressure microwave vapor-phase digestion method for difficult to digest organic samples.

A previously developed microwave heated vapor-phase digestion method for biological samples was modified to enable digestion of difficult to digest organic samples. Organic samples containing ca. 100 mg of organic carbon were digested using volume calibrated quartz inserts inside second generation type medium pressure microwave vessels. As digestion reagents, 98% sulfuric acid, 70% nitric acid and 30% hydrogen peroxide were used. The accuracy of the method was tested with six certified reference materials. Elements Ca, Fe, K, Na, Mg, P and Zn were determined from NIST-SRM 8433 corn bran. Elements Al, Fe, Cd, Cu, and Zn were determined from NRCC DOLT-2 dogfish liver. The element Cd was determined from IRMM-VDA Cd in polyethylene No. 001-004 reference materials. These elements were determined from digested samples by ICP-OES. The results were close or within certified limits. The modified method could digest nearly all the materials tested, including the above mentioned reference materials, 2-nitrobenzoic acid (2-NBA), 4-NBA and copper(II) phthalosyanine-3, 4',4',4'-tetrasulfonic acid tetrasodium salt (CPS). The method could not digest 3-NBA.

Journal Article↗