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11.
Tiainen J Soini Y Törmälä P Waris T Ashammakhi N 《Journal of biomedical materials research. Part B, Applied biomaterials》2004,70(1):49-55
The aim of this study was to assess tissue reactions to bioabsorbable self-reinforced polylactide/polyglycolide (SR-PLGA) 80/20 miniscrews in rabbit cranial bone. One PLGA screw was implanted on one side and one titanium screw on the other side of the sagittal suture (n = 21). Three animals were sacrificed after 2, 4, 8, 16, 24, 54, and 72 weeks. In histological examination the numbers of macrophages, giant cells, active osteoblasts, and fibrous tissue layers were assessed and degradation of the bioabsorbable screws was evaluated. After 2 weeks, macrophages were seen near the heads of both screws. After 4 and 8 weeks, the bioabsorbable screws were surrounded by fibrous tissue. Osteoblastic activity and groups of several giant cells were seen. After 24 weeks, a significant change in the morphology of the PLGA screws had occurred. Osteoblastic activity and the amount of giant cells had decreased. After 1 year, some PLGA biomaterial was still present. PLGA screws had been replaced by adipose tissue, fibrous tissue, and "foamy macrophages" that had PLGA particles inside them. After 1(1/2) years, the amount of biomaterial remaining had decreased remarkably. The particles of biomaterial were inside foamy macrophages. SR-PLGA 80/20 screws are biocompatible and have no clinically manifested complications when used in the cranial bone of rabbits. No contraindications as regards their clinical use in craniofacial surgery was found when these screws were studied in the cranial bones of rabbits. 相似文献
12.
Electrocardiogram (ECG) signals are the most prominent biomedical signal type used in clinical medicine. Their compression is important and widely researched in the medical informatics community. In the previous literature compression efficacy has been investigated only in the context of how much known or developed methods reduced the storage required by compressed forms of original ECG signals. Sometimes statistical signal evaluations based on, for example, root mean square error were studied. In previous research we developed a refined method for signal compression and tested it jointly with several known techniques for other biomedical signals. Our method of so-called successive approximation quantization used with wavelets was one of the most successful in those tests. In this paper, we studied to what extent these lossy compression methods altered values of medical parameters (medical information) computed from signals. Since the methods are lossy, some information is lost due to the compression when a high enough compression ratio is reached. We found that ECG signals sampled at 400 Hz could be compressed to one fourth of their original storage space, but the values of their medical parameters changed less than 5% due to compression, which indicates reliable results. 相似文献
13.
Juhani Smolander Veikko Louhevaara Timo Tuomi Olli Korhonen Juhani Jaakkola 《International archives of occupational and environmental health》1984,54(3):261-270
Summary Six healthy men aged 25 to 37 walked on a treadmill at work levels of 21 and 41% of their
for 25 to 30 min wearing gas protective clothing (GPC) consisting of an impermeable suit with a self-contained breathing apparatus (total weight 25 kg) or shorts (control tests, CT) in a temperate environment (t
a 24.3°C ± 1.0°C, rh 30–50%). When the GPC was worn at 21 and 41%
, the most prominent increases, compared with the CT, were noted in the heart rate (
± SE, 120 ± 5 vs 76 ± 3 beats min–1 and 171 ± 5 vs 103 ± 3 beats min–1), mean skin temperature (36.1 ± 0.2 vs 31.3° C ± 0.1°C and 36.9 ± 0.3 vs 30.9°C ± 0.4°C) and sweat rate (473 ± 51 vs 70 ± 23 g m–2 h–1 and 766 ± 81 vs 135 ± 18 g m–2 h–1) indicating a high cardiovascular and thermoregulatory strain, which was not decreased by ventilating the suit with an air flow of 281 min–1 at 41%
. The ventilation, oxygen consumption and production of carbon dioxide increased in relation to the extra weight of the GPC, partly dependent on the dynamic work level. It was concluded that the increase in the physiological load caused by the GPC was so high that the work-rest regimens, workers' level of physical fitness, cardiovascular health and heat tolerance should be considered whenever gas protective clothing is used. 相似文献
14.
15.
Schmitz Timo Meisinger Christa Kirchberger Inge Thilo Christian Amann Ute Baumeister Sebastian E. Linseisen Jakob 《European journal of epidemiology》2021,36(6):619-627
European Journal of Epidemiology - The aim of this study was to evaluate the impact of the COVID-19 pandemic lockdown on acute myocardial infarction (AMI) care, and to identify underlying stressors... 相似文献
16.
Soenke H Bartling Rajiv Gupta Attila Torkos Christian Dullin Grabbe Eckhardt Thomas Lenarz Hartmut Becker Timo St?ver 《Otology & neurotology》2006,27(4):491-498
HYPOTHESIS: Flat-panel based volume computed tomography could improve cochlear implant electrode evaluation in comparison with multislice computed tomography. BACKGROUND: Flat-panel based volume computed tomography offers higher spatial resolution and less metal artifacts than multislice computed tomography. Both characteristics could improve the evaluation of challenging but important questions in cochlear implantation assessment, such as an exact imaging of cochlea, osseous spiral lamina, electrode array position, and single electrode contacts. These questions are not currently fully answered by multislice computed tomography. METHODS: Four isolated temporal bone specimens were scanned in a current multislice computed tomography scanner and in two experimental flat-panel based volume computed tomography scanners before and after cochlea implantation. To compare flat-panel based volume computed tomography and multislice computed tomography, four features were rated according to the following criteria: 1) visibility of the cochlea; 2) visibility of the osseous spiral lamina; 3) discernibility of individual electrode contacts; and 4) the ability to determine the electrode array position relative to scala tympani and scala vestibuli. Layer-by-layer microgrinding pictures were used as the ground truth for verification of imaging findings. RESULTS: Flat-panel based volume computed tomography was superior to multislice computed tomography in all four features rated. The cochlea and facial nerve canal were much better delineated in flat-panel based volume computed tomography. The osseous spiral lamina and single electrode contacts were only visible in flat-panel based volume computed tomography. Assessment of implant position with regard to the cochlear spaces was considerably improved by flat-panel based volume computed tomography. CONCLUSION: Cochlear implantation assessment could be improved by flat-panel based volume computed tomography and, therefore, would be highly beneficial for cochlea implantation research and for clinical evaluation. However, these first results were shown by scanning isolated temporal bone specimens; scanning whole human skull bases might be more challenging. 相似文献
17.
Tarja Anttila Leena Tenkanen Sonja Lumme Maija Leinonen Randi Elin Gislefoss G?ran Hallmans Steinar Thoresen Timo Hakulinen Tapio Luostarinen P?r Stattin Pekka Saikku Joakim Dillner Matti Lehtinen Matti Hakama 《Cancer epidemiology, biomarkers & prevention》2005,14(2):385-389
OBJECTIVE: We assessed the risk of prostate cancer by exposure to Chlamydia trachomatis. METHOD: Seven hundred thirty eight cases of prostate cancer and 2,271 matched controls were identified from three serum sample banks in Finland, Norway, and Sweden by linkage to the population based cancer registries. RESULTS: A statistically significant inverse association (odds ratio, 0.69; 95% confidence interval, 0.51-0.94) was found. It was consistent by different serotypes and there was a consistent dose-response relationship. CONCLUSION: C. trachomatis infection is not likely to increase the risk of prostate cancer. Whether the inverse relationship is true or due to difficulties in measuring the true exposure in prostatic tissue by serology, confounders or other sources of error remain open. 相似文献
18.
Thomas Elter Peter Borchmann Holger Schulz Marcel Reiser Sven Trelle Roland Schnell Markus Jensen Peter Staib Timo Schink?the Hartmut Stützer Jürgen Rech Martin Gramatzki Walter Aulitzky Ibrahim Hasan Andreas Josting Michael Hallek Andreas Engert 《Journal of clinical oncology》2005,23(28):7024-7031
PURPOSE: To determine the efficacy and safety of a newly developed concomitant administration of fludarabine and alemtuzumab (FluCam) in patients with relapsed or refractory B-cell chronic lymphocytic leukemia (B-CLL). PATIENTS AND METHODS: A total of 36 patients were treated in this phase II study (median age, 61.47 years; mean number of prior chemotherapies, 2.6; Binet stage C, n = 28). After an initial dose escalation of alemtuzumab over 3 days, alemtuzumab 30 mg and fludarabine 30 mg/m2 were administered on 3 consecutive days. Treatment was repeated after 28 days for up to six cycles. Restaging (following National Cancer Institute criteria) was carried out after cycles 2 and 4 and 1 month after the end of treatment. RESULTS: The overall response rate was 83% (11 complete responses, 19 partial responses, one stable disease, and five progressive diseases). Two patients with progressive disease developed fungal pneumonias, and one patient died as a result of Escherichia coli sepsis. Two subclinical cytomegalovirus reactivations occurred. CONCLUSION: The new FluCam regimen is effective and feasible in patients with relapsed and refractory B-CLL. 相似文献
19.
Timo Rautio Matias Jaskari Tejas Gundgire Terho Iso-Junno Minnamari Vippola Antti Jrvenp 《Materials》2022,15(10)
Severe shot peening (SSP) was used on additive manufactured 316L by laser powder bed fusion. The effect of the post processing on the surface features of the material was analyzed through residual stress measurements, tensile testing, hardness-depth profiles, and fatigue testing by flexural bending. The results showed that SSP can be utilized to form residual stresses up to −400 MPa 200 μm below the surface. At the same time, a clear improvement on the surface hardness was achieved from 275 HV to near 650 HV. These together resulted in a clear improvement on material strength which was recorded at 10% improvement in ultimate tensile strength. Most significantly, the fatigue limit of the material was tripled from 200 MPa to over 600 MPa and the overall fatigue strength raised similarly from a low to high cycle regime. 相似文献
20.
Tanja Stachon Jiong Wang Achim Langenbucher Timo Eppig Markus Bischoff Berthold Seitz Nóra Szentmáry 《Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie》2013,251(11):2585-2590