Captopril: determination in blood and pharmacokinetics after single oral dose

The study describes a specific, precise, sensitive and accurate method for determination of unchanged captopril, an angiotensin-converting enzyme inhibitor, in human plasma. Captopril was stabilized by forming an adduct with p-bromophenacyl bromide and this adduct was measured by high-performance liquid chromatography with UV detection. The standard curve was linear over a range of 30-800 ng ml-1. The average yield of derivatization of the unchanged captopril was 73.6% and the recovery of captopril-adduct reached 93.1%. The limit of detection was 15 ng ml-1, while the quantitative limit was 30 ng ml-1. Inter- and intra-assay RSD was below 9%, but inter- and intra-assay accuracy was below 8%. On the basis of elaborated method, a single-dose pharmacokinetics in 12 men, in two doses (25 and 50 mg of captopril) has been investigated. The comparison of the pharmacokinetic parameters obtained from both doses of the drug have been made.     

Continuity in tactual–visual cross-modal transfer: Infancy to 11 years.

The present study demonstrated that individual differences in cross-modal transfer showed continuity over a 10-year span. Tactual–visual tasks, requiring visual recognition of shapes that had previously been felt but not seen, were given to full-term and preterm children at 2 ages, 1 and 11 years. Cross-modal performance showed a left-hand advantage at 11 years and, for both groups, cross-age correlations were significant when tactual exploration at 11 years was done with the left hand (r?=?.34–.36). The continuity showed some specificity in that the infant measure did not relate to other types of cross-modal performance at 11 years and was not dependent on aspects of spatial ability involving form perception. This continuity accounted for most of the previously reported relation of infant cross-modal ability to 11-year IQ. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Task space decomposition for invariant control of constrained robots

An approach, motivated by analytical mechanics and linear algebra methods, is proposed for task space decomposition. The approach relies on the introduction of a new set of kinematic parameters describing the constrained motion of the end-effector, using the analytical forms of material and program constraints. These parameters define a new basis in the end-effector configuration space. A general inner product characterized by the unity matrix is introduced in this basis and in its dual, which gives rise to the definition of a new set of metrics for the end-effector configuration space. The vectors defined in these bases are considered as pseudo-orthogonal. Returning to the original bases of the configuration space, the symmetric matrices for the vanishing bilinear forms can be defined. In this way, the freedom and constraint subspaces can be defined in a rigorous, analytical way. The physical meaning of the resulting metrics is explained. It is shown that the task space decomposition is invariant, although non-Euclidean metrics are being used. To illustrate the application of the methodology and to explain further the properties of the task space decomposition, two examples are presented. In the first example, the robot end-effector tracks a planar surface. A particular definition of the program constraint gives rise to the introduction of skewed bases, which better explains the inherent features of the approach. In the second example, a task of operating a planar joystick, with constrained orientation of the end-effector, is considered. The relevant bases of the task space are translated in this case and it is possible to explain other features of the method.     

Reference levels at European level for cardiac interventional procedures

In interventional cardiology, a wide variation in patient dose for the same type of procedure has been recognised by different studies. Variation is almost due to procedure complexity, equipment performance, procedure protocol and operator skill. The SENTINEL consortium has performed a survey in nine european centres collecting information on near 2000 procedures, and a new set of reference levels (RLs) for coronary angiography and angioplasty and diagnostic electrophysiology has been assessed for air kerma-area product: 45, 85 and 35 Gy cm(2), effective dose: 8, 15 and 6 mSv, cumulative dose at interventional reference point: 650 and 1500 mGy, fluoroscopy time: 6.5, 15.5 and 21 min and cine frames: 700 and 1000 images, respectively. Because equipment performance and set-up are the factors contributing to patient dose variability, entrance surface air kerma for fluoroscopy, 13 mGy min(-1), and image acquisition, 0.10 mGy per frame, have also been proposed in the set of RLs.     

Quality control measurements for fluoroscopy systems in eight countries participating in the SENTINEL EU coordination action

Quality control (QC) is becoming increasingly important in relation to the introduction of digital medical imaging systems using X rays. It was, therefore, decided to organise and perform a trial on image quality and physical measurements. The SENTINEL toolkit for QC measurements of fluoroscopy systems containing equipment and instructions for their use in the assessment of dose and image quality circulated among participants in the trial. The participants reported on their results. In the present contribution, the impact of the trial on the selected protocols is presented. The Medical Physics and Bioengineering protocol appeared to be useful for QC, and also for digital systems. The protocol needs an additional section, or an addition to each section, to state compliance with the requirements. The circular cross-sections of the Leeds test objects need adaptation for rectangular flat panel detector (FPD) systems. Only one participant was able to perform the monitor test using MoniQA. This is due to the fact that assistance is required from the suppliers of the X-ray systems. This problem needs to be solved to apply MoniQA in practice.     

Proposal for a patient database on cardiac interventional exposures for epidemiological studies

Relatively high organ doses absorbed by patients in interventional cardiology suggest the opportunity to define these patients as a cohort to be followed forward in time in an epidemiological study of the cancer risks associated with exposure to low-dose ionising radiation. In this paper, the UNSCEAR 2000 Report risk estimates for the most exposed organs/tissues in cardiac interventional procedures are reviewed, as well as the critical features of such an epidemiological study that is anticipated to have an intrinsically low statistical power because of the low levels of risk and possible confounding factors. To overcome these limitations, data collected in different institutions can be combined provided that a common design and conduct are used for dose assessment. A minimum dataset to be collected on a patient basis is proposed that can be implemented routinely in most facilities. This data should be linked to the local patient information system in order to retrieve all the exposures of a given patient.     

Hand exposure to ionising radiation of nuclear medicine workers

The specific nature of work in nuclear medicine departments involves the use of isotopes and handling procedures, which contribute to the considerable value of an equivalent dose received, in particular, by the fingertips. Standard nuclear medicine department uses ring dosemeters placed usually at the base of the middle finger. The main aim of the study was to find out whether a relationship exists between the doses recorded by thermoluminescent detectors placed at various locations on the radiopharmacists' hands and the doses recorded by the ring detectors, and to determine the character of that relationship. The correction factor represents a correction value to be used to calculate the doses which might be received by locations on the hand from the dose recorded by the ring dosemeter. The dose recorded by the ring dosemeter is on the average five times lower than that received by the fingertips of thumb, index and middle fingers.     

结构损伤与荷载的快速同步识别方法研究

本文仅以损伤因子为优化变量,提出一种结构损伤和荷载同步识别的方法。首先通过时域荷载识别的方法将未知荷载转化为损伤因子的函数,将近似荷载作用下的结构响应和实测响应的平方距离作为目标函数,从而降低了需要识别未知参数的数目;然后在目标函数的计算过程中,利用虚拟变形法（VDM）可进行结构快速重分析的思想,快速构造给定损伤因子下系统的脉冲响应,避免每步迭代重新集装系统矩阵,并通过荷载形函数方法进一步提高荷载识别的效率;最后利用二次多项式插值近似结构每个时刻的响应方法和推导对应目标函数的梯度表达式来提高优化搜索的速度。本文利用刚架模型进行数值模拟,准确识别了结构中柱子单元刚度损伤、附加质量以及梁上的未知移动荷载,并通过一个悬臂梁试验进一步验证所提出方法的准确性和可行性。     

Application of nickel-coated carbon fibre material in cathodic protection of underground-buried steel structures

The present paper reports the results of a preliminary study on potential suitability of a chopped nickel-coated carbon fibre (NiCCF) material to an impressed current, cathodic protection (CP) system, for an underground-buried steel structure. A primary role of a conductive NiCCF filler (Toho-Tenax^®-J MC HTA-12K A302 fibre) was to enhance distribution of a protective current, by significantly lowering the corrosion environment’s resistivity.Initially, the resistivity of sand-based soil (with humidity of ca. 20%) was optimized through addition of small amounts of chopped (15 ± 3 mm long) pieces of Toho-Tenax fibre. An operational efficiency for two laboratory CP setups (in the presence and absence of NiCCF soil modifier) was then monitored, over a period of 30 days. Each cathodic protection setup consisted of a protected structure (simulated by a steel rebar:  = 10 mm and length 0.5 m) and a DSA (Ti/MMO: _a = 95 mm) anode. Obtained results demonstrated a continuous increase of the soil resistivity parameter during a preliminary, 30-day cathodic polarization cycle, for the NiCCF-modified CP setup.