化学气相淀积反应器中超细粒子的形态控制 Ⅲ.TiO_2超细粒子晶体组成

在超细粒子粒度及粒度分布控制模型的基础上,对快相变速率和慢相变速率两种晶型转变情形,建立了化学气相淀积合成超细粒子过程中,表征超细粒子晶体组成及含量的物理模型和数学模型。利用该模型探讨了物系参数和操作参数对超细粒子晶体组成的影响,理论预测和实验结果相一致。     

数字化口腔种植外科导板的精确度研究

目的 本研究通过分析种植体术前设计和术后的三维位置,来评估数字化口腔种植导板的精确度.方法 根据修复体的生物学功能和美学要求,使用3D种植软件对种植体位置进行设计.将设计的种植导板转化为手术用种植导板,指导47颗种植体植入合适位置.通过重叠术前和术后的CT扫描图像,分析植体肩部和根部的线性误差以及植体长轴的角度误差,比...     

骨不连治疗的研究与技术应用进展*

背景：骨不连是骨折晚期常见的临床问题,数十年来,在各种新式内外固定材料、普及的显微外科技术、创新的植骨材料,尤其是分子生物学技术的全面帮助下,骨不连的治疗取得了突破性进展。
　　目的：总结骨不连治疗的研究进展,为以后更好地治疗骨不连提供技术理论和方法选择。
　　方法：由第一作者运用计算机检索系统检索1990年1月至2013年5月发表的有关骨不连原因及治疗方法的文献,以“fracture nonunion,treatment,progress”或“骨不连,治疗方法,进展”为检索词。同一领域则选择近期发表或者发表在权威杂志的文章。
　　结果与结论：排除重复性研究及时间跨度大的文献,从检索结果中共选择了48篇文章进一步分析。骨不连治疗手段主要有两种：非手术方式和手术方式,目前临床上以手术方式为主且高效。骨折愈合是多环节参与的复杂过程,一旦骨不连发生,应具体问题具体分析,根据患者的实际情况采取个体化治疗原则,重视软组织的保护,必要时联合运用多种手术及非手术方法,才能取得满意的疗效。     

Experience with NORPLANT® in Egypt

Experience with the contraceptive NORPLANT in Egypt dates back to early 1980 when the first multicentre trial was initiated. To date, more than 3000 women have received this contraceptive at the Assiut University Family Clinic alone. Analysis of the overall experience in this clinic has indicated a 5-year cumulative continuation rate of 51 and a pregnancy rate of 1.8 per 100 women.

Clinical pharmacology studies pertaining to the safety of NORPLANT in our community have indicated no deleterious effect on the lipid profile, liver functions and blood coagulation system. Two studies conducted in Egypt have indicated that the initiation of NORPLANT use shortly after delivery does not have any unfavourable effect on lactational performance, or on physical or psychomotor development of the breast-fed infants. This is particularly important in Arab and Moslem cultures where prolonged breast-feeding is emphasized.

A study utilizing focus-group discussion to assess users' attitudes to NORPLANT has indicated the need to improve the informational/educational package given in the service by emphasizing certain cultural considerations.

On the whole, this first implant method has proven to be safe and acceptable in Egypt, where there is a special need for long-term methods for contraception, particularly as sterilization is not socially acceptable.     

Implant outcomes: Towards a mixed methodology for evaluating the efficacy of adult cochlear implant programmes

Studies concerned with the efficacy of cochlear implants have traditionally focused on measuring enhancements in speech perception associated with implantation. This paper reports the findings of a study concerned with qualitative and quantitative measures of psychosocial benefit associated with the adult cochlear implant programme. Cochlear implants enhanced implantees' interpersonal communication skills and social confidence, and were associated with a reduction in the user's social anxiety. Broader socioeconomic gains were not achieved by implantees, mainly because of an absence of adequate employment and community education programmes associated with implant programmes.     

How Reliable Are Textured Implants Used in Breast Surgery? A Review of 510 Implants

Five hundred ten implants were used in 273 patients. The follow-up was between 3 months and 8 years. Four hundred nineteen prostheses were used for subglandular breast augmentation, 91 for subpectoral breast reconstruction. All the breasts were checked personally: 397 augmented breasts and 86 reconstructed breasts—94.7%. The objective criterion was the Baker classification: grades I and II, good result; and grades III and IV, poor result. Results were as follows: Baker I, 397 breasts; Baker II, 78 breasts (I + II, 98.3%); Baker III, 5 breasts; Baker IV, 3 breasts (III + IV, 1.7%). Three prostheses were removed after 3, 4, and 6 years because the textured surface was totally damaged. Two bilumen prostheses lost the saline fluid. The complication rate due to the implants was very low.     

颌间牵引钉对比牙弓夹板颌间牵引联合微型钛板坚固内固定治疗颌骨骨折临床分析

目的：探讨颌间牵引钉对比牙弓夹板行颌间牵引术联合微型钛板坚固内固定治疗颌骨骨折的临床疗效对比观察。方法：将2007年-2011年收治的82例颌骨骨折患者随即分为颌间牵引钉纽和牙弓夹板组,牙弓夹板组采用微型钛板坚固内固定联合牙弓夹板牵引治疗,颌间牵引钉组采用微型钛板坚固内固定联合颌间牵引钉牵引治疗。治疗后比较术后疗效;并在5个时间点测定DI、GI、CPITN指数。结果：经治疗后颌间牵引钉组总有效率为85．37％,牙夹板组总有效率为和78．02％,颌间牵引钉组总体疗效优于牙弓夹板组（Х^2=10．015,P〈0．05）;2组的DI、GI指数经治疗后均上升,但牙弓夹板组上升显著（P〈0．01）;术后两组CPITN指数。颌间牵引钉纽基本无变化,牙弓夹板纽显著升高（P〈0．01）。结论：领间牵引钉领间牵引联合微型钛板坚固内固定治疗领骨骨折治愈率高、治疗过程安全且对牙周组织不良刺激小。适合进行临床推广。     

Translational and rotational forces on heart valve prostheses subjected ex vivo to a 4.7-T MR system

PURPOSE: To assess the magnetic field interactions on 60 heart valve prostheses subjected to a 4.7 T MR system. It addresses the question of whether heart valves deemed safe at 1.5 T may pose safety hazards as patients are exposed to increased static magnetic fields. MATERIALS AND METHODS: Ex vivo testing was performed to evaluate translational and rotational forces on 60 heart valves using previously described techniques. RESULTS: Translational forces were detected on 58 heart valves ranging from 0.5 degrees to 7.5 degrees. Seven valves exhibited paramagnetic/weakly ferromagnetic behavior, and 51 valves exhibited diamagnetic behavior. Rotational forces were observed for 46 valves. CONCLUSIONS: Criteria previously used for safety assessment of heart valve prostheses and expressed in terms of magnetic forces suggest the forces observed in this study are compatible with the safe use of these valves in magnetic resonance (MR) systems with static fields up to 4.7 T.     

Neurostimulation systems for deep brain stimulation: in vitro evaluation of magnetic resonance imaging-related heating at 1.5 tesla

PURPOSE: To assess magnetic resonance imaging (MRI)-related heating for a neurostimulation system (Activa Tremor Control System, Medtronic, Minneapolis, MN) used for chronic deep brain stimulation (DBS). MATERIALS AND METHODS: Different configurations were evaluated for bilateral neurostimulators (Soletra Model 7426), extensions, and leads to assess worst-case and clinically relevant positioning scenarios. In vitro testing was performed using a 1.5-T/64-MHz MR system and a gel-filled phantom designed to approximate the head and upper torso of a human subject. MRI was conducted using the transmit/receive body and transmit/receive head radio frequency (RF) coils. Various levels of RF energy were applied with the transmit/receive body (whole-body averaged specific absorption rate (SAR); range, 0.98-3.90 W/kg) and transmit/receive head (whole-body averaged SAR; range, 0.07-0.24 W/kg) coils. A fluoroptic thermometry system was used to record temperatures at multiple locations before (1 minute) and during (15 minutes) MRI. RESULTS: Using the body RF coil, the highest temperature changes ranged from 2.5 degrees-25.3 degrees C. Using the head RF coil, the highest temperature changes ranged from 2.3 degrees-7.1 degrees C.Thus, these findings indicated that substantial heating occurs under certain conditions, while others produce relatively minor, physiologically inconsequential temperature increases. CONCLUSION: The temperature increases were dependent on the type of RF coil, level of SAR used, and how the lead wires were positioned. Notably, the use of clinically relevant positioning techniques for the neurostimulation system and low SARs commonly used for imaging the brain generated little heating. Based on this information, MR safety guidelines are provided. These observations are restricted to the tested neurostimulation system.