A microprocessor controlled multi-channel evoked potential data acquisition system

A stored program control system is described for the acquisition of evoked potential (EP) data. It is a small, portable and flexible system with a variety of input and output possibilities. The system presents a low cost solution to the problem of acquisition of evoked potential data. A novel method of converting and reducing sixteen channels of EEG analogue data to their digital equivalent is shown. It is adaptable for the inter active control of experiments and is sophisticated enough to deal with the complexities of experimental control as well as data manipulation. One of the major advantages of the system is that both the sequencing of the functions and their detailed make-up can be readily altered by programming to meet the individual requirements of any given situation.     

A versatile drop foot stimulator for research applications

Drop Foot Stimulators are used to correct hemiplegic drop foot by synchronising the application of Functional Electrical Stimulation (FES) of the Common Peroneal Nerve (CPN) to the swing phase of the gait cycle. A research Drop Foot Stimulator (DFS) has been developed with a very flexible architecture to enable the investigation of a variety of gait-correction strategies. The portable unit has been carefully designed to optimise functionality while keeping its size and power consumption to a minimum. The device has two channels of stimulation, with all parameters of stimulation for each channel independently programmable. Four analogue and four digital sensor input channels are provided with a wide variety of sensor types possible. A microcontroller core is utilised to enable the implementation of different control algorithms. A PC-based user interface enables easy programming of the system configuration.     

Flash芯片和LCD模块在便携式多导睡眠监测系统中的应用

目的：解决全指标便携式多导睡眠监测系统的信号采集、显示和数据储存问题。方法：选用低功耗单片机、大容量Flash芯片和LCD模块,通过软、硬件设计,实现多导信号的采集、显示和存储。结果：研制成功可实时多导采集、显示与储存12导生理信号的电路模块和驱动程序。结论：本文提供了适用于全指标便携式多导睡眠监测系统的信号采集、显示和数据储存的方法。     

基于80C196KC的串行数据采集及控制系统的设计

本文介绍了以单片机80C196KC为核心构成串行数据采集及控制系统,该系统通过串行口与计算机通信,计算机可发指令给单片机实现系统控制,单片机实现数据采集,并将数据实时地传回计算机.系统利用单片机丰富的软硬件资源,可以实现采样、通讯、计算、脉冲计数等多种功能.实验表明,该方案是可行的,系统电路结构简单、功耗低,具有较高的性能价格比,特别适合基于计算机的便携式医学仪器的数据采集和系统控制.该系统已成功地应用于便携式多参数监护仪的开发.     

Developing a drug library for smart pumps in a pediatric intensive care unit

BackgroundThe most serious medication errors occur during intravenous administration. The potential consequences are more serious the more critical and younger the patient. Smart pumps can help to prevent infusion-related programming errors, thanks to associated dose-limiting software known as “drug library”. Drug libraries alert the user if pre-determined high dosage limits are exceeded or if entry is below pre-determined low dosage limits.ObjectiveTo describe the process for developing a specific drug library for a pediatric intensive care unit (PICU) and the key factors for preventing programming errors.Methods and materialsThe study was performed by a multidisciplinary team consisting of a clinical pharmacist, a PICU pediatrician, and the chief nurse of the unit. The process of developing the drug library lasted seven months. A literature review was carried out to determine standard concentrations and accurate limits for intravenous administration of high-risk drugs. Alaris^® syringe pumps and Guardrails^® CQI v4.1 Event Reporter software were used.ResultsSeveral manufacturers offer smart pump technology. Users should be aware of differences in features, such as definition of parameters and associations between them, definition of safety limits, organization of the drug library, and data use. Our infusion pump technology covered 108 drugs. Compliance with the drug library was 85% and nurses’ acceptance of the drug library was high as 94% would recommend implementation of this technology in other units. After nine months of implementation, several potentially harmful infusion-related programming errors were intercepted.ConclusionsDrug libraries are specifically designed for a particular hospital unit, and may condition the success in implementing this technology. Implementation of smart pumps proved effective in intercepting infusion-related programming errors after nine months of implementation in a PICU.     

Four-dimensional computed tomography: image formation and clinical protocol

Respiratory motion can introduce significant errors in radiotherapy. Conventional CT scans as commonly used for treatment planning can include severe motion artifacts that result from interplay effects between the advancing scan plane and object motion. To explicitly include organ/target motion in treatment planning and delivery, time-resolved CT data acquisition (4D Computed Tomography) is needed. 4DCT can be accomplished by oversampled CT data acquisition at each slice. During several CT tube rotations projection data are collected in axial cine mode for the duration of the patient's respiratory cycle (plus the time needed for a full CT gantry rotation). Multiple images are then reconstructed per slice that are evenly distributed over the acquisition time. Each of these images represents a different anatomical state during a respiratory cycle. After data acquisition at one couch position is completed, x rays are turned off and the couch advances to begin data acquisition again until full coverage of the scan length has been obtained. Concurrent to CT data acquisition the patient's abdominal surface motion is recorded in precise temporal correlation. To obtain CT volumes at different respiratory states, reconstructed images are sorted into different spatio-temporally coherent volumes based on respiratory phase as obtained from the patient's surface motion. During binning, phase tolerances are chosen to obtain complete volumetric information since images at different couch positions are reconstructed at different respiratory phases. We describe 4DCT image formation and associated experiments that characterize the properties of 4DCT. Residual motion artifacts remain due to partial projection effects. Temporal coherence within resorted 4DCT volumes is dominated by the number of reconstructed images per slice. The more images are reconstructed, the smaller phase tolerances can be for retrospective sorting. From phantom studies a precision of about 2.5 mm for quasiregular motion and typical respiratory periods could be concluded. A protocol for 4DCT scanning was evaluated and clinically implemented at the MGH. Patient data are presented to elucidate how additional patient specific parameters can impact 4DCT imaging.     

Real-time supervisor system based on trinary logic to control experiments with behaving animals and humans

A new method is presented based on trinary logic able to check the state of different control variables and synchronously record the physiological and behavioral data of behaving animals and humans. The basic information structure of the method is a time interval of defined maximum duration, called time slice, during which the supervisor system periodically checks the status of a specific subset of input channels. An experimental condition is a sequence of time slices subsequently executed according to the final status of the previous time slice. The proposed method implements in its data structure the possibility to branch like an if-else cascade and the possibility to repeat parts of it recursively like the while-loop. Therefore its data structure contains the most basic control structures of programming languages. The method was implemented using a real-time version of LabVIEW programming environment to program and control our experimental setup. Using this supervision system, we synchronously record four analog data channels at 500 Hz (including eye movements) and the time stamps of up to six neurons at 100 kHz. The system reacts with a resolution within 1 ms to changes of state of digital input channels. The system is set to react to changes in eye position with a resolution within 4 ms. The time slices, experimental conditions, and data are handled by relational databases. This facilitates the construction of new experimental conditions and data analysis. The proposed implementation allows continuous recording without an inter-trial gap for data storage or task management. The implementation can be used to drive electrophysiological experiments of behaving animals and psychophysical studies with human subjects.     

A microprogrammed data acquisition system for renography.

The purpose of this project was to design an efficient, low cost, and portable system for renography suitable for clinical use. The principles involved in the renographic test, and the procedures and calculations which act on the design of our system, are given. The system consists of an Apple II Plus computer equipped with 48K memory, two disk drives with diskettes of 143K each, a thermal printer with graphic capability, the Microsoft Z80 card, and an interface which is specifically designed for renographic data acquisition.     

基于PIC单片机的便携式X线机主控系统设计与实现

目的：配合已有的高压系统,以PICl8F8722为主控CPU设计了一套X线机的主控系统,实现便携式X线机的摄影功能。方法：以常规摄影用X线机的功能为基础,采用kV、mAs二个参数控制曝光过程,曝光容量3．5kW;采用64K串行EEPROM存储芯片,保存胖、中、瘦3种体位,每种体位20个人体部位的曝光条件,实现体位程序摄影;系统可选用中文或英文操作界面;9种出错报警显示出错代码和具体出错信息：可配备有线或遥控双手闸曝光。结果：该系统结合高压发生系统、成像装置构成的便携式X线机,能够实现曝光条件选择、曝光控制、曝光过程检测、出错报警等功能,具有体积小、自动化程度高、控制方便等优点;同时系统具备冷高压测试的软件功能,方便系统调试和维修;系统设计充分考虑主控系统的硬件应用环境,预留充分的功能通道,以满足系统升级或不同的高压系统对主控板的改进要求。结论：该系统为便携式X线机、移动式床旁X线机系统的实现提供一个有效的解决方案,也可成为现有X线机技术更新的可行方案。     

水听器式便携超声参数测量系统的研制

目的：开发了一套测量声输出参数的系统，为进一步研制适用于军事计量巡检工作的便携式仪器奠定基础。方法：采用水听器作为换能器，采集超声信号存空间声场焦平面上一点的声压波形。通过对声压波形的参数进行数值运算，得到所关心的超声声输山参数。结果：能够在误差允许的范围内测量出主要的声输出参数。结论：该方法切实可行，得到的数据可重复性好。     

Portable cost-effective EEG data acquisition system

Neuro-cognitive dysfunctions are common clinical abnormalities found in society. They require objective analysis by various instruments; an important technique involves monitoring electroencephalogram (EEG) signals. To date, EEG machines have been robust, costly and require patients to come to a hospital for test. Therefore, we have constructed a simple, cheap and portable EEG instrument for wider patient use. It consists of two active digital EEG probes with two channels each, making it a four-channel portable acquisition system. It is further connected through a two-wire serial bus to the acquisition unit, which comprises an analogue to digital converter (ADC) and an ARM board processor with 2 GB memory and USB interface. The whole system is placed in a small box making it highly portable for wider use in clinical settings.     

Effect of exercise on physiological age-related change at mouse neuromuscular junctions

To determine the effect of endurance exercise on physiological age-related change at the mouse neuromuscular junction (NMJ), synaptic function was studied for extensor digitorum longus (EDL) and soleus muscles of three C57BL/6J mouse groups, 1) young adult control (YC: 10 months), 2) old control (OC: 20 months), and 3) old mice which exercised (OE: 20 months) since young-adulthood. Electrophysiological properties were studied with intracellular recording techniques. Safety margin was studied by measuring indirect isometric twitch tension in different calcium concentrations. With sedentary aging, EDL and soleus quantal contents increased. Following aging combined with 10 months of exercise, the EDL quantal contents in OE and YC animals were similar. In contrast, soleus quantal content was greater in OE than in YC animals. Determined safety margins were OC greater than YC = OE for EDL, and OC = YC = OE for soleus. This is the first study to indicate that physiological age-related changes at NMJs of EDL and soleus muscles are affected differently by endurance exercise. Exercise prevented all physiological age-related changes in EDL NMJs but not in soleus NMJs, this suggests that EDL changes are associated with inactivity during aging, while soleus changes are "fundamental" age changes.     

Glycolytic and gluconeogenic growth of Escherichia coli O157:H7 (EDL933) and E. coli K-12 (MG1655) in the mouse intestine

Escherichia coli EDL933, an O157:H7 strain, is known to colonize the streptomycin-treated CD-1 mouse intestine by growing in intestinal mucus (E. A. Wadolkowski, J. A. Burris, and A. D. O'Brien, Infect. Immun. 58:2438-2445, 1990), but what nutrients and metabolic pathways are employed during colonization has not been determined. In this study, when the wild-type EDL933 strain was fed to mice along with an EDL933 DeltappsA DeltapckA mutant, which is unable to utilize tricarboxylic acid cycle intermediates and gluconeogenic substrates for growth, both strains colonized the mouse intestine equally well. Therefore, EDL933 utilizes a glycolytic substrate(s) for both initial growth and maintenance when it is the only E. coli strain fed to the mice. However, in the presence of large numbers of MG1655, a K-12 strain, it is shown that EDL933 utilizes a glycolytic substrate(s) for initial growth in the mouse intestine but appears to utilize both glycolytic and gluconeogenic substrates in an attempt to maintain colonization. It is further shown that MG1655 predominantly utilizes glycolytic substrates for growth in the mouse intestine whether growing in the presence or absence of large numbers of EDL933. Data are presented showing that although small numbers of EDL933 grow to large numbers in the intestine in the presence of large numbers of MG1655 when both strains are fed to mice simultaneously, precolonization with MG1655 affords protection against subsequent colonization by EDL933. Moreover, in mice that are precolonized with EDL933, small numbers of MG1655 are able to grow rapidly in the intestine and EDL933 is eliminated. In situ hybridization experiments using E. coli-specific rRNA probes showed that while MG1655 is found only in mucus, EDL933 is found both in mucus and closely associated with intestinal epithelial cells. The data are discussed with respect to competition for nutrients and to the protection that some intestinal commensal E. coli strains might afford against infection by O157:H7 strains.     

Anesthetic effects on synaptic transmission and gain control in respiratory control

All volatile and most intravenous general anesthetics currently in clinical use cause respiratory depression at concentrations suitable for surgery. While various in vitro studies have identified potential molecular targets, their contributions to respiratory depression are poorly understood. At surgical concentrations, anesthetics principally affect ligand-gated, rather than voltage-gated ion channels. Here we focus on anesthetic-induced effects on synaptic transmission in brainstem respiratory neurons. The spontaneous discharge patterns of canine respiratory bulbospinal premotor neurons in vivo depend principally on NMDA and non-NMDA receptor-mediated excitation, while GABAA receptors mediate gain modulation and silent-phase inhibition. Studies examining the effects of volatile anesthetics on synaptic neurotransmission to these neurons suggest a primary role for postsynaptic enhancement of GABAA receptor function, partly offset by a reduction in presynaptic inhibition and a presynaptic reduction in glutamatergic excitation. In studies involving canine inspiratory hypoglossal motoneurons in vivo, which are already strongly depressed by low concentrations (< 0.5 MAC) of volatile anesthetics, the role of acid-sensitive, two-pore domain K+ (TASK) channels was found to be minimal at these subanesthetic concentrations. Potentiation of GABAA receptor-mediated inhibition was suggested. These studies on canine respiratory neurons provide valuable insights into mechanisms of anesthetic depression within a respiratory control subsystem; future studies will be required to determine anesthetic effects on sources of respiratory drive, rhythm, and their control.     

Disuse of rat muscle in vivo reduces protein kinase C activity controlling the sarcolemma chloride conductance

Muscle disuse produced by hindlimb unloading (HU) induces severe atrophy and slow-to-fast fibre type transition of the slow-twitch soleus muscle (Sol). After 2 weeks HU, the resting ClC-1 chloride conductance ( g _Cl) of sarcolemma, which controls muscle excitability, increases in Sol toward a value typical of the fast-twitch EDL muscle. After 3 days of HU, the g _Cl increases as well before initiation of fibre type transition. Since ClC-1 channels are acutely silenced by PKC-dependent phosphorylation, we studied the modulation of g _Cl by PKC and serine–threonine phosphatase in Sol during HU, using a number of pharmacological tools. We show that a fraction of ClC-1 channels of control Sol are maintained in an inactive state by PKC basal activity, which contributes to the lower g _Cl in control Sol compared to EDL. After 14 days of HU, PKC/phosphatase manipulation produces effects on Sol g _Cl that corroborate the partial slow-to-fast transition. After 3 days of HU, the early increase of g _Cl in Sol is entirely attributable to a reduction of PKC activity and/or activation of phosphatase, maintaining ClC-1 channels in a fully active state. Accordingly, we found that HU reduces expression of PKCα, ɛ, and θ isoenzymes in Sol and EDL muscles and reduces total PKC activity. Moreover, we show that the rheobase current is increased in Sol muscle fibres as soon as after 3 days of HU, most probably in relation to the increased g _Cl. In conclusion, Sol muscle disuse is characterized by a rapid reduction of PKC activity, which reduces muscle excitability and is likely to contribute to disuse-induced muscle impairment.     

Portable cost-effective EEG data acquisition system

Neuro-cognitive dysfunctions are common clinical abnormalities found in society. They require objective analysis by various instruments; an important technique involves monitoring electroencephalogram (EEG) signals. To date, EEG machines have been robust, costly and require patients to come to a hospital for test. Therefore, we have constructed a simple, cheap and portable EEG instrument for wider patient use. It consists of two active digital EEG probes with two channels each, making it a four-channel portable acquisition system. It is further connected through a two-wire serial bus to the acquisition unit, which comprises an analogue to digital converter (ADC) and an ARM board processor with 2 GB memory and USB interface. The whole system is placed in a small box making it highly portable for wider use in clinical settings.     

Effects of jump training on passive mechanical stress and stiffness in rabbit skeletal muscle: role of collagen

AIMS: This study evaluated the effect of a 15-week jump training period on mechanical parameters and collagen concentration of different muscle types in rabbits, at 50, 90 and 140 days of age. METHODS: Trained (T) animals were made to jump over obstacles in order to get food and water. The height of the obstacle was increased according to the animal's age. Control (C) animals were sedentary. Mechanical parameters (force, stress, stiffness) and collagen concentration were measured in Extensor Digitorum Longus (EDL), Rectus Femoris (RF), Semimembranosus Proprius (SMP) and Psoas Major (PSOAS). RESULTS: Both EDL and RF collagen concentrations and passive mechanical parameters increased between 50 and 140 days of age (P<0.001), whereas SMP and PSOAS collagen concentrations decreased (P<0.001). Soluble collagen concentration decreased similarly with age in all muscles and groups. Exercise training at 140 days induced a significant increase in force (EDL 20.4% and RF 15.3%, 0.01相似文献   

Dose-volume considerations with linear programming optimization.

A method of incorporating dose-volume considerations within the framework of conventional linear programming is presented. This method is suitable for the optimization of beam weights and angles using a conformal treatment philosophy (i.e., tailoring the high-dose region to the target volume only). Dose-volume constraints are introduced using the concept that volumes of normal tissue nearer the target volume will be allowed higher dose constraints than volumes of normal tissue distal to the target volume. Each involved normal structure is divided into high-dose and low-dose volumes. These two volume partitions are represented by constraint points with either high-dose or low-dose constraints, respectively. Optimized treatment plans for three clinical sites demonstrate that this technique meets or surpasses the original dose-volume constraints for a conformal-type treatment plan using straightforward linear programming in a time frame that is comparable to other linear programming problems.     

A general software package for the handling of medical images.

PICS (portable imaging computer software), is a software system designed for handling and processing a variety of types of medical image. It has been designed to satisfy the following criteria: (a) the software should be portable between different items of hardware with minimal alteration; (b) there should be a simple operator interface to enable use by inexperienced users, while avoiding the need for experienced users to be directed through tedious menu trees; (c) the programming environment should enable simple integration of new data handling protocols. To meet these requirements the software was written in FORTRAN using structured subroutine organization. The software has basic image handling and processing facilities and contains a comprehensive set of nuclear medicine clinical protocols. Other facilities include alignment of images from different modalities with display of superimposed images and ability to handle, analyse and display three-dimensional data sets. Data transfer programs have been written to capture data from gamma camera, CT, MRI, ultrasound and radiographs by converting the images to a common data format. The system provides a hospital with a central digital image handling resource, enabling investigation of the value of digital image processing in potential clinical applications.