Fat and water separation in balanced steady-state free precession using the Dixon method.

In this work the feasibility of separating fat and water signals using the balanced steady-state free precession (SSFP) technique is demonstrated. The technique is based on the observation (Scheffler and Hennig, Magnetic Resonance in Medicine 2003;49:395-397) that at the nominal values of TE = TR/2 in SSFP imaging, phase coherence can be achieved at essentially only two orientations (0 degrees and 180 degrees ) relative to the RF pulses in the rotating frame, under the assumption of TR < T2, and independently of the SSFP angle. This property allows in-phase and out-of-phase SSFP images to be obtained by proper choices of the center frequency offset, and thus allows the Dixon subtraction method to be utilized for effective fat-water separation. The TR and frequency offset for optimal fat-water separation are derived from theories. Experimental results from healthy subjects, using a 3.0 Tesla system, show that nearly complete fat suppression can be accomplished.     

螺旋CT三维重建成像在先天性高肩胛症手术方式选择中的作用

[目的]探讨螺旋CT三维重建技术在先天性高肩胛症分度和手术方式选择中的作用。[方法]22例先天性高肩胛症术前应用螺旋CT对病变部位进行扫描并三维重建，测量以肩胛骨肩胛冈内侧缘为参照点，两侧肩胛骨高度差。根据测量结果依据Cavendish分度将其分类，并根据三维重建成像选择不同的矫形手术术式。[结果]本组22例病人，随访2—4年，外观及功能均有不同程度的改善，未出现神经、血管和椎体等的损伤。[结论]根据螺旋CT扫描和三维重建检查结果，术前即可直观的明确先天性高肩胛症的病变程度，相互关系，伴发畸形，患侧肩胛骨与正常对侧肩胛骨的外观差异等，便于手术操作方案的制定，避免了手术操作的盲目性，减少医源性并发症的发生。     

薄壁构件的高温低周疲劳寿命的预测与验证

提出了文题的计算模型,它采用非线性弹塑性蠕变有限元法,计算构件危险点在高温及周期保载的交变载荷谱作用下的应力应变响应,以应变范围区分法累积损伤,从而求出构件的疲劳寿命,并以带孔矩形薄板为例作了计算与验证,结果吻合较好,可供工程应用。     

ANALYSIS OF BURIED BUMPER SYNDROME AFTER PERCUTANEOUS ENDOSCOPIC GASTROSTOMY DUE TO USE OF A BUTTON‐TYPE KIT

Background: Buried bumper syndrome (BBS) is a rare complication of percutaneous endoscopic gastrostomy (PEG). Along with the widespread use of the button‐type kit, BBS is encountered frequently. Methods: In the present study, we examined causes and treatments for BBS among 1400 patients who had undergone PEG. Results: The causes of BBS after PEG were classified into two categories: early causes consisted of wound infection, inappropriate size of kit and severe lordosis, while late causes were inappropriate exchange of kit, rough management or weight gain. The treatments for BBS could be determined by the degree of wound infection, fistula and burial of the bumper. Conclusion: We prepared a flowchart for replacement, by which BBS can be managed safely and quickly without surgical or endoscopic intervention.     

A simple and reliable method for rapidly harvesting split skin grafts in rats

A technique is presented which allows the rapid precise harvesting of split-skin grafts in rats. This technique uses the skin which would have been discarded in the formation of an open wound as a donor site thus reducing the overall assault on the animal.     

氟西汀与阿米替林治疗105例抑郁障碍病人的双盲对照试验

目的：评价国产氟西汀的抗抑郁作用及安全性。方法：采用随机、双盲对照、多中心研究，分为国产氟西汀组５７例（男性２２例，女性３５例；年龄４０±ｓ１３ａ），口服氟西汀２０ｍｇ，ｑｄ，阿米替林５７例（男性２７例，女性３０例；年龄４０±１４ａ），口服阿米替林７５ｍｇ，ｂｉｄ，疗程６ｗｋ。结果：氟西汀治疗抑郁障碍的疗效与阿米替林相当，总有效率分别为８５％及９２％（Ｐ＞０．０５）；氟西汀组的主要副作用有口干、便秘、恶心、心动过速等，但较之阿米替林程度轻且发生率低。结论：氟西汀的抗抑郁作用与阿米替林相当，副作用少，服用方便。     

一次手术法对自制两段式种植体种植效果的实验研究

本实验用自制纯钛两段式种植体,以一次手术法植入到狗的下颌前磨牙区,观察5个月,结果表明,观察期间内牙龈无炎症,种植体稳固,X线片显示种植体周围无透射区,镜下可见种植体表面与牙龈之间形成上皮附着样结构,与骨组织之间大多呈骨性愈合。提示了两段式种植体有两种设计和手术方式可供选择。骨内部分在开放的环境中也可达到骨性愈合。     

金属换热器传热过程的数学模型及应用

应用蒙特卡洛法仿真辐射式金属换热器内的辐射传热过程，建立了换热器综合传热的数学模型，利用概率论原理，把辐射能迁移过程仿真为一定累积概率分面下的随机过程，该模型能较好地反映换热器内传热过程的真实情况，可以计算出换热器内烟气、筒壁、空气的温度和壁面热流分布，以及研究烟气进口温度、换热器筒径和狭逢宽度对换热效果的影响。     

Invasive techniques for the diagnosis of respiratory infectious diseases

Conclusion Reviewing the history of diagnostic procedures of causative organisms of respiratory infections, invasive techniques such as the protected specimen catheter (PSB) and bronchoalveolar lavage (BAL) have become the preferred choices because they have many advantages. These methods cause the patient relatively little discomfort, and permit an early diagnosis since they can easily be performed at the bedside and the causative organism from the disease site is obtained in cultures. These procedures can be used not only in patients with community-acquired lung infections, but also in immunocompromised hosts, including those with blood diseases or following renal transplantation, in patients in intensive care units and in mechanically-ventilated patients so that the cause can be accurately determined and chemotherapy started quickly, resulting in better therapeutic efficacy. Although these invasive procedures are advantageous for the diagnosis of respiratory infections, they also present various problems which remain to be addressed including minimizing contamination and setting diagnostic threshold values. However, the importance of accurately determining the causative organism in respiratory infections should be recognized as the most important factor, and these methods have shown to date to provide the most accurate information to aid in the timely treatment of respiratory infections in a wide variety of patients.