高精度遥感技术在物探施工中的应用——以塔里木盆地柯东4号构造三维线束项目为例

以往遥感技术受到数据低分辨率的限制，在物探施工过程中所起作用不大。近些年随着其分辨率的提高，可以对遥感数据进行深层次的挖掘。在塔里木盆地柯东4号构造三维线束项目的施工过程中，利用相应的地信软件对遥感数据进行属性提取，采用加权算法获取该项目物理点的优度值，并对物理点进行合理偏移。预设计过的物理点提供给测量班组进行放样。实验证明，高精度遥感技术在西北物探施工过程中，可以利用相关地理信息系统软件进行自动选点设计以获得最佳物理点位置，有效地提高生产效率。     

Improved Fourier-transform-based parallel receive beam formation

A Fourier transform (FT)-based technique for forming parallel receive beams has been previously employed to increase the imaging frame rate in ultrasonic imaging. However, the image quality in FT-based parallel reconstruction is degraded because differences in range focusing delays are ignored and a wide transmit beam needs to be used. In this paper, an adaptive weighting technique based on a focusing-quality index is used to reduce the sidelobes of the FT-derived parallel receive beams. The focusing-quality index is derived from the spatial spectrum of the received aperture data after the receive delays have been applied. Since the spatial spectrum of the baseband aperture data is also used to approximate receive beams in FT-based parallel reconstruction, the adaptive weighting technique can be directly combined with the FT-based technique for forming parallel receive beams with only a slight increase in system complexity. Real ultrasound data are used to demonstrate the efficacy of the proposed technique on both wire targets and speckle-generating objects. The results clearly demonstrate the effectiveness in reducing the sidelobes. In addition, the image background noise is suppressed. The principles, experimental results, and the extension of the proposed technique to 3D ultrasound imaging are described in this paper.     

Using the Delphi technique in economic evaluation: time to revisit the oracle?

BACKGROUND AND OBJECTIVE: Although the Delphi technique has been commonly used as a data source in medical and health services research, its application in economic evaluation of medicines has been more limited. The aim of this study was to describe the methodology of the Delphi technique, to present a case for using the technique in economic evaluation, and to provide recommendations to improve such use. METHODS: The literature was accessed through MEDLINE focusing on studies discussing the methodology of the Delphi technique and economic evaluations of medicines using the Delphi technique. RESULTS AND DISCUSSION: The Delphi technique can be used to provide estimates of health care resources required and to modify such estimates when making inter-country comparisons. The Delphi technique can also contribute to mapping the treatment process under investigation, to identifying the appropriate comparator to be used, and to ensuring that the economic evaluation estimates cost-effectiveness rather than cost-efficacy. CONCLUSION: Ideally, economic evaluations of medicines should be based on real-patient data. In the absence of such data, evaluations need to incorporate the best evidence available by employing approaches such as the Delphi technique. Evaluations based on this approach should state the limitations, and explore the impact of the associated uncertainty in the results.     

Validation of a new surgical procedure for percutaneous scaphoid fixation using intra-operative ultrasound

A new technique for percutaneous fixation of non-displaced scaphoid fractures is described. The technique used pre-operative planning from computed tomography images, registration to intra-operatively acquired three-dimensional ultrasound images, and intra-operative guidance using an optical tracking system. Two stand-alone software applications were developed. The first one was used to determine the surgical plan pre-operatively and the second one was used to guide the surgeon during screw insertion. Laboratory validation of the technique included measurements of the inter-operator and intra-operator variability in the outcome of scaphoid fixation using the proposed procedure, and also included comparison of the performance of this procedure with the conventional percutaneous fixation technique using fluoroscopy. The results showed that the tight accuracy requirements of percutaneous scaphoid fixation were met and that the consistency was superior to the conventional technique.     

Detection of interference by cyclobenzaprine in liquid-chromatographic assays of tricyclic antidepressants

We evaluated a technique for detecting cyclobenzaprine interference with liquid-chromatographic assays for tricyclic antidepressants. The technique involves dual-wavelength absorbance monitoring of the column effluent at 214 and 254 nm. Ratios of analyte peak heights at each wavelength are used to check for the presence of co-eluting interferences. With this technique, one can detect interference with an amitriptyline assay caused by 10 micrograms of cyclobenzaprine per liter.     

Ultrasound of the elbow: Examination techniques and US appearance of the normal and pathologic joint

Ultrasound studies are frequently requested for the work-up of patients with local elbow pain, which is generally caused by overuse syndromes, trauma, inflammatory diseases, or neuropathies. The technique used to examine this joint will vary to some extent depending on the precise location of the pain and other clinical findings. The aim of this article is to describe the standard technique used for elbow ultrasound, the normal anatomy of the joint, and the appearance on ultrasound of normal elbow anatomy and the alterations associated with some of the more common disorders affecting this joint.     

Transthecal digital block: an underutilized technique in the ED

The transthecal digital block is a simple, safe, and effective anesthesia technique that can be used in many digital injuries. It is contraindicated only in cases of infection. The purposes of this article are to (1) discuss the indications for the transthecal digital block, (2) describe the technique, and (3) review the literature. The transthecal technique is used on appropriate patients almost to the exclusion of more traditional digital blocks by many hand surgeons. The advantages of this method are that it requires only a single injection, has a rapid onset of action, and requires only a small amount of anesthetic. It also has virtually no risk of direct mechanical trauma to the neurovascular bundles. This technique has been shown to be exceptionally effective. We encourage emergency physicians to use the transthecal technique when indicated.     

实时灰阶二维血流显像技术的临床应用进展

实时二维灰阶血流成像技术是利用数字编码超声技术对血流、血管壁及周围软组织进行实时观察,并以灰阶方式显示的一种新型影像技术。近年来已越来越广泛地应用于颈部动脉、外周静脉、肝脏、浅表器官及产前等的检查中,成为多普勒血流检测的重要补充。     

Volumetric evaluation of upper extremities in 250 healthy persons

BACKGROUND AND PURPOSE: Upper extremity oedema frequently occurs as a complication of several diseases. The aim of this study was to establish normative data for upper extremity volumes with a modified water displacement method. These data were used to develop predictive formulas helpful in detecting abnormal swelling. SUBJECTS AND METHODS: Upper extremities of 250 healthy subjects (138 men and 112 women) were measured by water displacement. RESULTS: A mean difference of 3.0% (3.2%) between right and left arm (forearm) was found. Intra-class correlation coefficients were 0.99 for intra-rater and inter-rater reliabilities. Coefficient of variation was 0.23%. To predict the premorbid volume of an oedematous arm, prediction formulas were constructed. DISCUSSION AND CONCLUSION: Water displacement as used in this study is a highly reliable technique for volume measurement of upper extremities. This technique was applied to gather normative data for upper extremity volumes. We suggest that this technique can be used in daily clinical practice for the evaluation of upper extremity oedema or atrophy caused by various diseases as well as for volume monitoring. Prediction formulas can be used to define abnormal swelling.     

MARS (Molecular Adsorbents Recirculating System). New technique of extracorporeal depuration in liver failure

MARS (Molecular Adsorbent Recirculating System) is a new technique as a system of liver detoxification in patients with severe acute or acute on chronic hepatic failure. Also, it has shown its usefulness in the control of resistant pruritus in the primary biliary cirrhosis. Due to the fact that this technique is often delivered in Intensive Care Units (ICUs), we have reviewed the literature 1999 until now to describe this technique, its benefits and its mains complications. The technique was developed in Germany, where in 1999 was first used in clinical practice. It was used for the first time in Spain in 2000 and in the Clínica Universitaria of Navarra in July of 2001. Despite the short clinical experience using MARS its obvious beneficial effects such as decrease of hepatic toxins and the improvement of encephalopathy and hemodynamic situation, makes it a very useful technique in these patients. MARS has been shown to be a safe procedure, well tolerated by patients and accessible to the use by specialised nurses. Despite the encouraging clinical results, its used is still limited. Moreover its high cost precludes it widespread use and requires further studies.     

Intraabdominal microdialysis – methodological challenges

Microdialysis is used for in vivo sampling of extracellular molecules. The technique provides a continuous and dynamic view of concentrations of both endogenous released and exogenous administered substances. Microdialysis carries a low risk of complications and has proven to be a safe procedure in humans. The technique has been applied in several clinical areas, including gastrointestinal surgery. Microdialysis may be used for studies of tissue metabolism, and the technique is also a promising tool for pharmacological studies of drug penetration into abdominal organ tissue and the peritoneal cavity. The clinical significance of intraabdominal microdialysis in postoperative monitoring of surgical patients has yet to be proven. In this review, we introduce the microdialysis technique, and we present an overview of theoretical and practical considerations that should be taken into account when using microdialysis in intraabdominal clinical research.     

Improvement of tissue harmonic imaging using the pulse-inversion technique

Harmonic imaging has brought about significant improvements in image quality by taking advantage of the second harmonic component, but it still has one shortcoming, namely, a low signal-to-noise ratio. In this paper, a pulse-inversion technique is used in second harmonic imaging for biologic tissues to increase the signal-to-noise ratio. Enhancement of the second harmonic component is theoretically analyzed based on the theory of the finite amplitude sound wave and confirmed by the measurement. Second harmonic imaging for biologic tissues is constructed with the pulse-inversion technique and compared with the traditional fundamental frequency and also with second harmonic imaging before the use of this technique. Results demonstrate that this technique yields a dramatically cleaner and sharper contrast between the different structures of biologic tissues in ultrasonic images.     

Autocorrelation-based technique for automated segmentation of endocardial border in 3D echocardiograms

Left-ventricular (LV) segmentation is essential in the early detection of heart disease, where left-ventricular wall motion is being tracked in order to detect ischemia. In this paper, a new method for automated segmentation of the left-ventricular chamber is described. An autocorrelation-based technique isolates the LV cavity from the myocardial wall on 2-D slices of 3D short-axis echocardiograms. A morphological closing function and median filtering are used to generate a uniform border. The proposed segmentation technique is designed to be used in identifying the endocardial border and estimating the motion of the endocardial wall over a cardiac cycle. To this purpose, the proposed technique is particularly successful in border delineation by tracing around structures like papillary muscles and the mitral valve, which constitute the typical obstacle in LV segmentation techniques. The results using this new technique are compared to the manual detection results in short-axis views obtained at the papillary muscle level from 3D datasets in human and canine experiments in vivo. Qualitatively, the automatically-detected borders are highly comparable to the manually-detected borders enclosing regions in the left-ventricular cavity with a relative error within the range of 4.2%-6%. Thus, the new technique constitutes a robust segmentation method for automated segmentation of endocardial borders and is suitable for wall motion tracking for automated detection of ischemia in vivo.     

Quantitation of some pancreatic juice exocrine proteins in the presence of radiocontrast medium used in endoscopic retrograde pancreatography (ERP)

The endoscopic collection of human pancreatic juice for chemical analysis is facilitated by the use of radiocontrast media. However, the effects of this material on pancreatic juice and the techniques used to analyze its proteins are unknown. This study has demonstrated no detrimental effects of a commonly used contrast medium on the pancreatic juice itself or on the analytic technique of radioimmunoassay and radial immunodiffusion. Likewise, the Phadebas enzymatic technique for amylase was not affected by this material. We conclude that techniques for the collection of pure pancreatic juice using radiocontrast material do not interfere with the analysis of pancreatic juice proteins using the techniques described.     

高强聚焦超声"切除"肿瘤的机理

本文对近年兴起的高强聚焦超声技术“切除”肿瘤的机理,做了全面的评述与讨论。指出,热机制是它第一位的重要机理。在一般情况下,最好限于利用热机制;而在另外一些情况下,则可有控制地利用空化机制。对监控超声空化发生的技术也做了讨论。     

A modified Kleihauer technique for the quantification of foetomaternal haemorrhage

The Kleihauer technique, based on acid elution of maternal red cells, is the mostly widely used technique in the UK to screen for, and estimate the volume of, foetomaternal haemorrhage (FMH) and for determining the need for additional doses of anti-D immunoglobulin to prevent maternal alloimmunization. However, technicians often report difficulties in identifying and accurately counting maternal red cells in the blood film, leading to imprecision in the calculated FMH. In this report, we describe a simple modification of the standard Kleihauer technique, based on performing acid elution of only half of the film. Compared to the standard method, the modified technique showed improved accuracy and reduced interobserver variability across a range of simulated FMH volumes. There was a high degree of correlation between the new technique and FMH estimated by flow cytometry (r2 = 0.916, P < 0.001). Technicians found the new technique easy to incorporate into routine practice in a busy teaching hospital laboratory and were impressed by the relative ease of counting maternal ghost cells. The modified technique has been used routinely in our laboratory for 3 years, during which time our performance in the UK National External Quality Assurance Scheme for FMH has been uniformly satisfactory.     

Percutaneous puncture guided by ultrasonic multitransducer scanning.

A technique for percutaneous puncture guided by real-time scanning is described. By means of a special puncture adaptor fastened to one end of a multitransducer, a needle can be guided in the plane of scanning in an adjustable angle to the transducer front. By this technique, the puncture target as well as the needle can be monitored on the real-time image during the entire puncture procedure. The technique has been used for amniocentesis, fine needle biopsy of a renal mass, renal cyst puncture, and pericardiocentesis.     

Single-needle insertion in twin amniocentesis

Amniocentesis in twin gestation is an uncommon event for most medical centers. The current technique used for this procedure includes two or more needle insertions and the introduction of dye into the first sac. A new approach that consists of a single insertion is proposed. The advantages of this alternate technique are that it requires only one insertion, it is a swifter procedure, it does not require the injection of dye, and it offers positive proof of tapping the two gestational sacs. Although this technique may have some potential risks, in our judgment the advantages outweight the potential risks, and this technique should be considered and its feasibility evaluated in cases of twin gestation requiring two-sac tapping.     

显微共聚焦拉曼技术在细菌分类鉴定中的应用

拉曼光谱可以用于识别和描述微生物的特征,作为当今微生物分类鉴定研究的热点.相比于传统的微生物分离培养技术和分子生物学鉴定技术,拉曼技术具有免培养、快速和高效等优点.随着光学领域拉曼技术和分子生物学的结合发展,使得微生物的鉴定变得更加高效快捷.拉曼显微光谱结合稳定同位素探针、荧光原位杂交和光镊技术,为研究生态系统中不可培...     

上颌前牙埋伏阻生的正畸治疗探讨

目的探讨上颌前牙埋伏阻生的矫治方法。方法应用固定正畸技术结合牙槽外科手术助萌法和闭合式开窗导萌术,对18例上颌埋伏阻生前牙进行矫治。结果应用助萌法矫治8例,闭合式开窗导萌法矫治10例,埋伏阻生牙均牵引成功,牙髓活力测试正常,牙周组织附着良好。结论应用固定正畸技术结合牙槽外科手术助萌法和闭合式开窗导萌法治疗上颌埋伏阻生前牙,可取得良好的矫治效果。