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排序方式: 共有983条查询结果,搜索用时 15 毫秒
71.
Sadia Nasrin Noriko Katsube Robert R. Seghi Stanislav I. Rokhlin 《Dental materials》2018,34(5):726-736
Objectives
The objective is to establish an approximate relative fatigue life estimation method under simulated mastication load for thin-walled monolithic restorations.Methods
Experimentally measured fatigue parameters of fluormica, leucite, lithium disilicate and yttrium-stabilized zirconia in the existing literature were expressed in terms of the maximum cyclic stress and stress corresponding to initial crack size prior to N number of loading cycles to assess their differences. Assuming that failures mostly originate from high stress region, an approximate restoration life method was explored by ignoring the multi-axial nature of stress state. Experiments utilizing a simple trilayer restoration model with ceramic LD were performed to test the model validity.Results
Ceramic fatigue was found to be similar for clinically relevant loading range and mastication frequency, resulting in the development of an approximate fatigue equation that is universally applicable to a wide range of dental ceramic materials. The equation was incorporated into the approximate restoration life estimation, leading to a simple expression in terms of fast fracture parameters, high stress area ΔA, the high stress averaged over ΔA and N. The developed method was preliminarily verified by the experiments. The impact of fast fracture parameters on the restoration life was separated from other factors, and the importance of surface preparation was manifested in the simplified equation. Both the maximum stress and the area of high stress region were also shown to play critical roles.Significance
While nothing can replace actual clinical studies, this method could provide a reasonable preliminary estimation of relative restoration life. 相似文献72.
Wali AS Khan RS 《Journal of the College of Physicians and Surgeons--Pakistan : JCPSP》2012,22(2):118-119
With the increase in incidence of ectopic pregnancy over the decades, bilateral ectopic pregnancy is also increasing. It is usually associated with assisted reproductive techniques (ART) but in recent years few cases of spontaneous bilateral ectopic pregnancy have been reported. Gynaecologists should be aware of this and that ultrasonography has limitations in diagnosis. In cases of ectopic pregnancy where contralateral adnexa is not clearly identified on ultrasound and fertility needs to be conserved, patient should be managed by experts in well equipped centres. A case of spontaneous bilateral tubal pregnancy that remained undiagnosed till laparotomy, is described. 相似文献
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74.
Ventilator-associated pneumonia is associated with significant patient morbidity, mortality, and increased health care costs. In the current economic climate, it is crucial to implement cost-effective prevention strategies that have proven efficacy. Multiple prevention measures have been proposed by various expert panels. Global strategies have focused on infection control, and reduction of lower airway colonization with bacterial pathogens, intubation, duration of mechanical ventilation, and length of stay in the intensive care unit. Routine use of the Institute for Healthcare Improvement ventilator care bundle is widespread, and has been clearly demonstrated to be an effective method for reducing the incidence of ventilator-associated pneumonia. In this article, we examine specific aspects of the Institute for Healthcare Improvement bundle, better-designed endotracheal tubes, use of antibiotics and probiotics, and treatment of ventilator-associated tracheobronchitis to prevent ventilator-associated pneumonia. 相似文献
75.
State and nonstate health programs in developing countries are often influenced by priorities that are defined in the Millennium Development Goals (MDGs). In the wake of recessionary pressures, policy makers in the health sector are often seen to divert significant budgets to some specific health programs and make only token allocations for other health problems that are important but do not fall under the traditional MDG box of health priorities. This paper illustrates the economic argument for investment in one such program: The eye health program and employs a country case study of Pakistan to demonstrate that there are significant economic gains that are being foregone by not addressing the needs of the blind in poverty reduction strategies. By applying appropriate growth and discounting factors and using the average wage rate, the paper estimates the total productivity gains that are realizable over a period of 10 years if the blind population in Pakistan is rehabilitated and their carers released to participate in the mainstream economic activity. Our findings indicate that significant productivity gains accumulated over 10 years, range from Rs. 61 billion (US$ 709 million) to Rs. 421 billion (US$ 4.9 billion) depending upon whether the entire blind population or only those affected by a specific cause are rehabilitated. The per annum productivity gains of rehabilitating the entire blind population represents 0.74% of the current gross domestic product of Pakistan, which is higher than the total public spending on health. In order to reap these benefits, the subsequent absorption of the rehabilitated blind and their carers into mainstream economic activity is as important as their effective rehabilitation. 相似文献
76.
Serotonin inhibits Na+/H+ exchange activity via 5-HT4 receptors and activation of PKC alpha in human intestinal epithelial cells 总被引:3,自引:0,他引:3
Gill RK Saksena S Tyagi S Alrefai WA Malakooti J Sarwar Z Turner JR Ramaswamy K Dudeja PK 《Gastroenterology》2005,128(4):962-974
BACKGROUND & AIMS: Increased serotonin levels have been implicated in the pathophysiology of diarrhea associated with celiac and inflammatory diseases. However, the effects of serotonin on Na+ /H+ exchange (NHE) activity in the human intestine have not been investigated fully. The present studies examined the acute effects of 5-hydroxytryptamine (5-HT) on NHE activity using Caco-2 cells as an in vitro model. METHODS: Caco-2 cells were treated with 5-HT (.1 micromol/L, 1 h) and NHE activity was measured as ethyl-isopropyl-amiloride (EIPA)-sensitive 22Na uptake. The effect of 5-HT receptor-specific agonists and antagonists was examined. The role of signaling intermediates in 5-HT-mediated effects on NHE activity was elucidated using pharmacologic inhibitors and immunoblotting. RESULTS: NHE activity was inhibited significantly (approximately 50%-75%, P < .05) by .1 micromol/L 5-HT via inhibition of maximal velocity (Vmax) without any changes in apparent affinity (Km) for the substrate Na+ . NHE inhibition involved a decrease of both NHE2 and NHE3 activities. Studies using specific inhibitors and agonists showed that the effects of 5-HT were mediated by 5-HT4 receptors. 5-HT-mediated inhibition of NHE activity was dependent on phosphorylation of phospholipase C gamma 1 (PLC gamma 1) via activation of src-kinases. Signaling pathways downstream of PLC gamma 1 involved increase of intracellular Ca 2+ levels and subsequent activation of protein kinase C alpha (PKC alpha). The effects of 5-HT on NHE activity were not cell-line specific because T84 cells also showed NHE inhibition. CONCLUSIONS: A better understanding of the regulation of Na+ absorption by 5-HT offers the potential for providing insights into molecular and cellular mechanisms involved in various diarrheal and inflammatory disorders. 相似文献
77.
78.
Ritesh Kumar Syed Saeed Ahmed Gulam Sarwar Hashmi Md. Kalim Ansari Sajjad Abdur Rahman 《Journal of maxillofacial and oral surgery》2016,15(3):336-344
Aim
The present study was planned to investigate the etiology of injuries and to analyze correlation between clinical and radiological findings in cases of craniomaxillofacial trauma.Study Design
An 18 months cross-sectional study was done and 325 patients with maxillofacial fractures were analyzed from January 2013 to June 2014 who reported to the department of oral and maxillofacial surgery, Aligarh, Uttar Pradesh. Data was recorded in a preformed case sheet which included: patient’s demographic data, cause of injury, type of injury, treatment plan.Results
Out of the 325 patients, 74.4 % were males with a male: female ratio of 2.91:1. The 21–30 year age group was found to be maximum. Road traffic accidents accounted for 71.3 %, followed by fall from height (19 %) and assault (9.5 %). Most commonly involved vehicles were two wheelers followed by public transport. Mandibular fractures (65 %) were most prevalent, followed by zygomaticomaxillary complex (44.27 %), parietal bone (48 %) and orbital fractures (21.3 %). Thirty-seven fractures (7.14 %) were missed clinically which were confirmed later by radiographic technique. Maximum were in cranium region (57 %) followed by mandible (27 %), mid face region (16.21 %). Thirty-three fractures (6.37 %) were overestimated or suspected clinically which could not be confirmed by radiographic technique. Maximum were in mandible (48.5 %) followed by mid face (36.33 %) and cranium (15.15 %).Conclusion
The idea behind this article is to analyze the various trends and affecting factors and correlation between clinical and radiological findings. A better understanding of the above said would help in future treatment planning and management of facial injuries.79.
Summary: Fucoidan is one of the main bioactive components of polysaccharides. The current study was focused on the anti-tumor effects of fucoidan on human heptoma cell line HepG2 and the possible mechanisms. Fucoidan treatment resulted in cell cycle arrest and apoptosis of HepG2 cells in a dose-dependent manner detected by MTT assay, flow cytometry and fluorescent microscopy. The results of flow cytometric analysis revealed that fucoidan induced G2/M arrest in the cell cycle progression. Hoechst 33258 and Annexin V/PI staining results showed that the apoptotic cell number was increased, which was associated with a dose-dependent up-regulation of Bax and down-regulation of Bcl-2 and p-Stat3. In parallel, the up-regulation of p53 and the increase in reactive oxygen species were also observed, Which may play important roles in the inhibition of HepG2 growth by fucoidan. In the meantime, Cyelin B 1 and CDK1 were down-regulated by fucoidan treatment. Down-regulation of p-Stat3 by fucoidan resulted in apoptosis and an increase in ROS in response to fucoidan exposure. We therefore concluded that fucoidan induces apoptosis through the down-regulation of p-Stat3. These results suggest that fucoidan may be used as a novel anti-cancer agent for hepatocarcinoma. 相似文献
80.