Computer-based Data Acquisition System Research Articles

THE effect of P2X7 receptor activation on functional responses of human left internal mammary artery.

The Purinoreceptor 7 (P2X7R) has become a promising drug target in many cardiovascular diseases, including coronary artery disease, since prolonged activation of P2X7R could promote vascular dysfunction, atherosclerosis, and thrombosis. Thus, we aimed to study the effects of P2X7R activation on vascular relaxation responses of the human left internal mammary artery (LIMA). Sections of redundant human LIMA were cut into 3-mm wide rings,, suspended in 20-mL organ baths containing physiologic salt solution, and attached to an isometric force transducer connected to a computer-based data acquisition system. Long-term (60min) incubation with specific P2X7R agonist Bz-ATP caused significant reductions in relaxation responses of LIMA to ATP and acetylcholine, which were reversed by selective P2X7R antagonists Brilliant Blue G or AZ11645373, whereas there were no changes in relaxation responses to endothelium-independent vasodilators isoprenaline, cAMP analog 8-Br-cAMP, and nitric oxide donor sodium nitroprusside. The impairment in relaxant responses of LIMA to endothelium-dependent vasodilators following activation of P2X7R for the long-term may contribute to postoperative LIMA vasospasm and hypertension. Modulation of P2X7R activity with selective agents may represent a new potential therapeutic approach in patients undergoing coronary artery bypass grafting surgery.

The Functional Effects of Visfatin on Human Left Internal Mammary Artery.

Visfatin may play a role in vascular dysfunction in metabolic disorders. Apart from its insulin-mimetic actions, it has divergent actions in the cardiovascular system with discordant results in the literature. Thus, we aimed to study the effects of visfatin on vascular responses of the human left internal mammary artery. Sections of redundant human left internal mammary artery were cut into 3-mm wide rings and hung in 20-mL organ baths containing physiologic salt solution and attached to an isometric force transducer connected to a computer-based data acquisition system. Removing endothelium caused an increase in pD2 values for visfatin-induced relaxation responses (10 -12 -10 -7 M) (9.06 ± 0.21 and 11.08 ± 0.92, respectively). Nicotinamide phosphoribosyltransferase inhibitor FK866 (10 µM) reversed the visfatin-induced relaxations (10 -12 -10 -7 M) ( P = 0.024). Incubations with nitric oxide synthase inhibitor nitro- l -arginine methylester and guanylate cyclase inhibitor 1H-[1,2,4] oxadiazolo [4,3-a] quinoxalin-1-one (ODQ) caused significant reductions in relaxation responses of visfatin ( P = 0.011 and 0.008, respectively). Visfatin incubations decreased relaxation responses to acetylcholine but not to sodium nitroprusside. Incubations with visfatin did not change contractile responses to angiotensin II, endothelin-1, noradrenalin, and phenylephrine. In this study, visfatin caused endothelium-dependent relaxations mediated by nitric oxide-cyclic guanosine monophosphate pathway and nicotinamide phosphoribosyltransferase activity. Furthermore, visfatin-induced decreases in relaxation responses were also related to endothelium-derived nitric oxide.

Displacement prediction of precast concrete under vibrationusing artificial neural networks

This paper intends to progress models to accurately estimate the behavior of fresh concrete under vibration using artificial neural networks (ANNs). To this end, behavior of a full scale precast concrete mold was investigated numerically. Experimental study was carried out under vibration with the use of a computer-based data acquisition system. In this study measurements were taken at three points using two vibrators. Transducers were used to measure time-dependent lateral displacements at these points on mold while both mold is empty and full of fresh concrete. Modeling of empty and full mold was made using ANNs. Benefiting ANNs used in this study for modeling fresh concrete, mold design can be performed. For the modeling of ANNs: Experimental data were divided randomly into two parts such as training set and testing set. Training set was used for ANN\'s learning stage. And the remaining part was used for testing the ANNs. Finally, ANN modeling was compared with measured data. The comparisons show that the experimental data and ANN results are compatible.

Development of Low Cost Miniature USB Based Data Acquisition System for Biomedical Instrumentation

In biomedical instrumentation, computer based data acquisition system is required for recording of physiological parameters and bioelectric signals, which allows signal processing, display, analysis and storage in digital media. However, Most of the commercially available PC based Data Acquisition systems are of very high cost and requires specific commercial software, again at a very high cost. Moreover, if the data is not stored in raw binary or known format, it is not possible for the user to use the data in other system or software of their own choice. Therefore, a low cost, simple and open source PC based data acquisition system for biomedical application would be very useful for biomedical instrument developers and researchers in the low resource countries. In this work, we present such development of data acquisition system. The developed system utilizes an 8-bit ordinary low cost microcontroller and some electronic circuit component to develop the data acquisition system and implementation of USB 1.1 (Universal Serial Bus) interface to PC. The onboard 10-bit ADC of the microcontroller was used for analog data sampling. Two sampling and data transfer mode is implemented, (i) Continuous mode with low sampling rate (800 sample/sec) and practically real time plotting and (ii) Batch mode, with high sampling rate (76.9 k sample/sec) but with batch type plotting. To evaluate the system, PC side GUI (Graphical User Interface) software was also developed. The GUI of system shows that a test sinusoidal signal is reproduced very nicely without any amplitude and phase distortion within the frequency band of 1 to 10 KHz. The system is suitable for low frequency bioelectric signals like ECG, EEG etc. and as well as high frequency signal like EMG, NCV etc. The system is low cost, miniature, simple, and efficient and being used in several indigenously developed medical devices like ECG, EMG, NCV and FIM [Rabbani et al, 1999] at the authors’ department with excellent satisfactory results.Bangladesh Journal of Medical Physics Vol.10 No.1 2017 1-11

APPLICATION OF SELF ORGANIZING MAP FOR CORRELATION HUNTING BETWEEN ALPHA BAND POWER OF EEG SIGNALS AND OTHER PHYSIOLOGICAL PARAMETERS DURING MUSLIM PRAYER (SALAT)

This study investigates a new approach to determine the correlations between alpha ([Formula: see text]) electroencephalography (EEG) and other physiological parameters during Muslim prayer (Salat) utilizing the self organizing map (SOM). The powerfulness of SOM in visualizing, understanding, and exploring the complexity in multivariable data can be used to determine the relationships between the input variables. Thirty healthy Muslim male subjects were recruited in the study. Their electroencephalogram (EEG), electrocardiogram (ECG), respiration rate (RSP), and oxygen saturation (SPO2) were continuously recorded using computer-based data acquisition system (MP150, BIOPAC Systems Inc., Camino Goleta, California). Three maps were constructed to determine the correlations in pre-baseline, during Salat, and post-baseline conditions utilizing SOM. The visualized results during Salat indicated that, alpha power (P[Formula: see text]) showed significant positive correlation in the occipital and parietal electrodes with the normalized unit of high-frequency HF (n.u.) power of heart rate variability (HRV) components (as a parasympathetic index), heart rate (HR), and RSP. Significant negative correlation was also observed between P[Formula: see text] with the normalized unit of low-frequency LF (n.u.) power and LF/HF of HRV (as sympathetic indices). SPO2 showed no correlation with P[Formula: see text]. While the results in pre-baseline and post-baseline conditions also did not show any correlation between the variables. The SOM proves that it can be successfully employed as a powerful technique in correlation analysis. The results were presented and compared with a previous study. Thus, it can be applied successfully in various biomedical engineering applications.

Neutron Flux Signal Acquisition from Plant Instrumentation Channel of Research Reactor for Reactivity Calculation

A design for instantaneous neutron flux signal acquisition system is being carried out for reactivity measurement of the nuclear research reactor. It is a computer-based digital data acquisition system that can perform continuous monitor and measurement of reactivity inserted into or removed from the research reactor. The acquisition system accomplishes with two major parts. The first part is an interfacing PCI based data acquisition card and the corresponding driver software intending to on-line acquisition of neutron flux signals from plant instrumentation channel. The second part incorporates the high-level Visual Basic real time program, indigenously developed for computation of reactivity by the solution of neutron point kinetic equations and other relevant functional modules like input file logging, reactivity calculation, graphics demonstration etc.

Prediction of behavior of fresh concrete exposed to vibration using artificial neural networks and regression model

This paper aims to develop models to accurately predict the behavior of fresh concrete exposed to vibration using artificial neural networks (ANNs) model and regression model (RM). For this purpose, behavior of a full scale precast concrete mold was investigated experimentally and numerically. Experiment was performed under vibration with the use of a computer-based data acquisition system. Transducers were used to measure time-dependent lateral displacements at some points on mold while both mold is empty and full of fresh concrete. Modeling of empty and full mold was made using both ANNs and RM. For the modeling of ANNs: Experimental data were divided randomly into two parts. One of them was used for training of the ANNs and the remaining part was used for testing the ANNs. For the modeling of RM: Sinusoidal regression model equation was determined and the predicted data was compared with measured data. Finally, both models were compared with each other. The comparisons of both models show that the measured and testing results are compatible. Regression analysis is a traditional method that can be used for modeling with simple methods. However, this study also showed that ANN modeling can be used as an alternative method for behavior of fresh concrete exposed to vibration in precast concrete structures.

Investigation of fresh concrete behavior under vibration using mass-spring model

This paper deals with the behavior of fresh concrete that is under vibration using mass-spring model (MSM). To this end, behaviors of two different full scale precast concrete molds were investigated experimentally and theoretically. Experiments were performed under vibration with the use of a computer-based data acquisition system. Transducers were used to measure time-dependent lateral displacements at some points on mold while mold is empty and full of fresh concrete. Analytical modeling of molds used in experiments were prepared by three dimensional finite element method (3D FEM) using software. Modeling of full mold, using MSM, was made to solve the problem of dynamic interaction between fresh concrete and mold. Numerical displacement histories obtained from time history analysis were compared with experimental results. The comparisons show that the measured and computed results are compatible.

Experimental confirmation for the validity of Ritz method in structural dynamic analysis

The issue of Ritz vectors and their advantages is well-known in the field of structural engineering. This study deals with Ritz analysis and its experimental support. To that end, two different precast concrete molds were handled. Experiments were performed under vibration with the use of a computer-based data acquisition system. Transducers were used to measure displacement histories on the mold. Three dimensional finite element (3D FEM) simulation modeling of the concrete mold was carried out to obtain deflection histories on the mold. The computed displacement histories were compared with the experimental testing results. The comparisons show that the experimental and numerical results are compatible.

Synergism of ochratoxin B and calcium-channel antagonist verapamil caused mitochondrial dysfunction

We examined the mechanism by which the ochratoxin B induced interaction with calcium-channel antagonist verapamil and mitochondrial dysfunction of the rat trachea in vitro experiment. The tracheas were cut into 2–3 mm wide rings and suspended in a tissue bath. Isometric tension was continuously measured with an isometric force transducer connected to a computer-based data acquisition system. Verapamil (1 × 10−6 M) produced a concentration-dependent contraction response in rat’s tracheal rings pre-contracted by acetylcholine. Incubation of rat’s tracheal rings with the ochratoxin B significantly potentiated the contraction responses of verapamil. Verapamil and OTB accelerate the overloading of Ca2+ in tracheal smooth muscle contributes the tissue toxicity as shown in electron microscopy and mitochondrial enzymes, through a mechanism that could involve perturbations of Ca2+ homeostasis. These results proved that ochratoxin B is a potential vasoconstrictor mycotoxin with the presence of calcium-channel antagonist. In conclusion, disturbance of Ca2+ homeostasis caused by OTA and plays a significant role in produces toxicity through mitochondrial enzyme inhibition.

Low-cost open-source multifunction data acquisition system for accurate measurements

Engineers and scientists commonly use data acquisition hardware and software to research unknown characteristics through measurement and analysis. Computer-based data acquisition systems are a powerful, flexible, and cost-effective measurement solution. This paper presents the hardware and firmware design of a low-cost computer-based data acquisition system that can be very interesting for conducting laboratory experiments and industrial applications. Its open-source philosophy opens the door for free software users and developers that would be interested in contributing with the project.

Effect of Muslim prayer (Salat) on α electroencephalography and its relationship with autonomic nervous system activity.

This study investigated the effect of Muslim prayer (salat) on the α relative power (RPα) of electroencephalography (EEG) and autonomic nervous activity and the relationship between them by using spectral analysis of EEG and heart rate variability (HRV). Thirty healthy Muslim men participated in the study. Their electrocardiograms and EEGs were continuously recorded before, during, and after salat practice with a computer-based data acquisition system (MP150, BIOPAC Systems Inc., Camino Goleta, California). Power spectral analysis was conducted to extract the RPα and HRV components. During salat, a significant increase (p<.05) was observed in the mean RPα in the occipital and parietal regions and in the normalized unit of high-frequency (nuHF) power of HRV (as a parasympathetic index). Meanwhile, the normalized unit of low-frequency (nuLF) power and LF/HF of HRV (as sympathetic indices) decreased according to HRV analyses. RPα showed a significant positive correlation in the occipital and parietal electrodes with nuHF and significant negative correlations with nuLF and LF/HF. During salat, parasympathetic activity increased and sympathetic activity decreased. Therefore, regular salat practices may help promote relaxation, minimize anxiety, and reduce cardiovascular risk.

AN IN-HOUSE COMPUTER-BASED DATA ACQUISITION AND CONTROL SYSTEM FOR ANAEROBIC FERMENTATION PROCESSES

A computer-based Data Acquisition and Control System (DACS) capable of monitoring the temperature, pH and gas production as well as maintaining a pre-determined temperature profile and feeding regime in anaerobic reactors was developed and tested. The hardware for the DACS was a series-based system consisting of a host processor which drives three modules-a digital input mode (MODULE 255), an analog input node (MODULE 254) and a digital output node (MODULE 253)-through a Serial Communication Adaptor connected to the serial asynchronous communication port of the host processor. The system was tested using two sets of laboratory model reactors maintained under two diurnally cyclic temperature ranges of 20-40°C and 15-25°C. Hydraulic retention time was varied from 10 to 25 days using the control system. The temperature and pH of the reactors were monitored at 30 sec interval. Results showed that the system was able to maintain the desired temperature to within ±2.5°C for the 20-40°C and ±1.0°C for the 15-25°C cycle. It was also able to maintain the desired feeding regime and to monitor and record the temperature, pH and gas production at the desired interval of time.

Computer-Aided Mold Design Algorithm for Precast Concrete Elements

This paper aims to determine a computer-aided mold design algorithm for precast concrete products to be produced by external vibrators. For this purpose, the behaviors of two different precast concrete molds were investigated experimentally and analytically. Experiments were performed under vibration with the use of a computer-based data acquisition system. Transducers were used to measure time-dependent lateral displacements at some points on the mold while it is empty and full of fresh concrete. Test results indicate that the difference between displacement amplitudes of empty and full molds is considerably high. Three-dimensional analytical modeling of molds used in experiments was prepared by finite element method using software. Modeling of the full mold was made to solve the problem of dynamic interaction of fresh concrete mold. In light of experimental, numerical, and literature studies, a mold design algorithm was established for precast concrete elements. Using this algorithm, a computer-aided mold design was carried out theoretically for a sample mold system.

Cardiorespiratory coupling of sympathetic outflow in humans: a comparison of respiratory and cardiac modulation of sympathetic nerve activity to skin and muscle

What is the central question of this study?Muscle sympathetic nerve activity (MSNA) is well known to be modulated by the arterial baroreceptors and respiration, but what are the magnitudes of cardiac and respiratory modulation of skin sympathetic nerve activity (SSNA), which primarily subserves thermoregulation?What is the main finding and what is its importance?Using direct microelectrode recordings of MSNA and SSNA in awake humans, we show that the magnitude of respiratory modulation of SSNA is identical to that of MSNA, the primary difference between the two sources of sympathetic outflow being the greater cardiac modulation of MSNA. This emphasises the role of the baroreceptors in entraining sympathetic outflow to muscle. It is well known that microelectrode recordings of skin sympathetic nerve activity (SSNA) in awake human subjects reveal spontaneous bursts of activity with no overt modulation by changes in blood pressure or respiration, in contrast to the clear cardiac and respiratory modulation of muscle sympathetic nerve activity (MSNA). However, cross-correlation analysis has revealed that, like individual muscle vasoconstrictor neurones, the firing of individual cutaneous vasoconstrictor neurones is temporally coupled to both the cardiac and respiratory rhythms during cold-induced cutaneous vasoconstriction, and the same is true of single sudomotor neurones during heat-induced sweating. Here, we used cross-correlation analysis to determine whether SSNA exhibits cardiac and respiratory modulation in thermoneutral conditions and to compare respiratory and cardiac modulation of SSNA with that of MSNA. Oligounitary recordings of spontaneous SSNA (n = 20) and MSNA (n = 18) were obtained during quiet, unrestrained breathing. Respiration was recorded by a strain-gauge transducer around the chest and ECG recorded by surface electrodes. Respiratory and cardiac modulation of SSNA and MSNA were quantified by fitting polynomial equations to the cross-correlation histograms constructed between the sympathetic spikes and respiration or ECG. The amplitude of the respiratory modulation (52.5 ± 3.4%) of SSNA was not significantly different from the amplitude of the cardiac modulation (46.6 ± 3.2%). Both were comparable to the respiratory modulation of MSNA (47.7 ± 4.2%), while cardiac modulation of MSNA was significantly higher (89.8 ± 1.5%). We conclude that SSNA and MSNA share similar levels of respiratory modulation, the primary difference between the two sources of sympathetic outflow being the marked cardiac modulation of MSNA provided by the baroreceptors.

Orthogonal least squares method and its application to nonlinear modeling of automotive engine fuelled with palm oil methyl esters

In this paper, nonlinear mathematical models for an automotive engine fuelled with palm biodiesel (Palm Oil Methyl Ester) are developed. Assuming a discrete time form for the system model, a polynomial Nonlinear Autoregressive exogenous (NARX) with a linear-in-parameter model structure is selected in this work. Real-time data obtained using a computer-based data acquisition system from a 2.0L automotive diesel engine test-bed unit is used for parameter estimation. The orthogonal least squares (OLS) algorithm together with the Error Reduction Ratio (ERR) criteria are used to select the significant terms in the NARX models in order to determine a parsimonious model and estimate the parameters of nonlinear model. Finally, the models are validated by plotting the output predicted by the models and comparing it with the measured output. The modelling error of both models is examined.

Design and development of an automated, portable and handheld tablet personal computer-based data acquisition system for monitoring electromyography signals during rehabilitation

This article describes the design of a robust, inexpensive, easy-to-use, small, and portable online electromyography acquisition system for monitoring electromyography signals during rehabilitation. This single-channel (one-muscle) system was connected via the universal serial bus port to a programmable Windows operating system handheld tablet personal computer for storage and analysis of the data by the end user. The raw electromyography signals were amplified in order to convert them to an observable scale. The inherent noise of 50 Hz (Malaysia) from power lines electromagnetic interference was then eliminated using a single-hybrid IC notch filter. These signals were sampled by a signal processing module and converted into 24-bit digital data. An algorithm was developed and programmed to transmit the digital data to the computer, where it was reassembled and displayed in the computer using software. Finally, the following device was furnished with the graphical user interface to display the online muscle strength streaming signal in a handheld tablet personal computer. This battery-operated system was tested on the biceps brachii muscles of 20 healthy subjects, and the results were compared to those obtained with a commercial single-channel (one-muscle) electromyography acquisition system. The results obtained using the developed device when compared to those obtained from a commercially available physiological signal monitoring system for activities involving muscle contractions were found to be comparable (the comparison of various statistical parameters) between male and female subjects. In addition, the key advantage of this developed system over the conventional desktop personal computer-based acquisition systems is its portability due to the use of a tablet personal computer in which the results are accessible graphically as well as stored in text (comma-separated value) form.

A spatial filtering velocimeter for solid particle velocity measurement based on linear electrostatic sensor array

A novel spatial filtering velocimeter for solid particle velocity measurement in gas-solid flow system is presented based on a Linear Electrostatic Sensor Array (LESA) in the paper. The fundamental spatial filtering principle of the LESA is theoretically described, and a differential filter based on two LESAs is further proposed to remove the pedestal component of the output signal from the LESA. Thus solid particle velocity can be measured by determining the central frequency of the periodic output signal of the differential filter. A spatial filtering velocimeter consisting of a measurement head, seven-channel differential amplifiers and a computer-based data acquisition and processing system is designed and its performance is evaluated on a purpose-built gravity-fed particle flow rig and a belt rig, respectively. Experimental results show that the system repeatability is within ±5.4% over the velocity range of 1.72–3.91 m/s for a particle concentration range 0.011–0.163 m3/m3.

Characterization of heat emission of light-curing units

This study was designed to analyze the heat emissions produced by light-curing units (LCUs) of different intensities during their operation. The null hypothesis was that the tested LCUs would show no differences in their temperature rises. FIVE COMMERCIALLY AVAILABLE LCUS WERE TESTED: a "Flipo" plasma arc, "Cromalux 100" quartz-tungsten-halogen, "L.E. Demetron 1" second-generation light-emitting diode (LED), and "Blue Phase C5" and "UltraLume 5" third-generation LED LCUs. The intensity of each LCU was measured with two radiometers. The temperature rise due to illumination was registered with a type-K thermocouple, which was connected to a computer-based data acquisition system. Temperature changes were recorded in continues 10 and 20s intervals up to 300s. The Flipo (ARC) light source revealed the highest mean heat emission while the L.E. Demetron 1 LED showing the lowest mean value at 10 and 20s exposure times. Moreover, Cromalux (QTH) recorded the second highest value for all intervals (12.71, 14.63, 14.60) of heat emission than Blue Phase C5 (LED) (12.25, 13.87, 13.69), interestingly at 20s illumination for all intervals the highest results (18.15, 19.27, 20.31) were also recorded with Flipo (PAC) LCU, and the lowest (6.71, 5.97, 5.55) with L.E. Demetron 1 LED, while Blue Phase C5 (LED) recorded the second highest value at the 1st and 2nd 20s intervals (14.12, 11.84, 10.18) of heat emission than Cromalux (QTH) (12.26, 11.43, 10.26). The speed of temperature or heat rise during the 10 and 20s depends on light intensity of emitted light. However, the QTH LCU was investigated resulted in a higher temperature rise than LED curing units of the same power density. The PAC curing unit induced a significantly higher heat emission and temperature increase in all periods, and data were statistically different than the other tested groups (p<.05). LED (Blue Phase C5) was not statistically significant (p<.05) (at 10s) than QTH units, also LED (Blue Phase C5, UltraLume 5) generates obvious heat emission and temperature rises than QTH units (at 20s) except for those which have lower power density of LED curing units (first generation). Thus, the null hypothesis was rejected.

The Effect of Ion Current Density on Target Etching in Radio Frequency-Magnetron Sputtering Process

The effect of ion current density of argon plasma on target sputtering in magnetron sputtering process was investigated. Using home-made ion probe with computer-based data acquisition system, the ion current density as functions of discharge power, gas pressure and positions was measured. A double-hump shape was found in ion current density curve after the analysis of the effects of power and pressure. The data demonstrate that ion current density increases with the increase in gas pressure in spite of slightly at the double-hump site, sharply at wave-trough and side positions. Simultaneously, the ion current density increases upon increase in power. Especially, the ion current density steeply increases at the double-hump site. The highest energy of the secondary electrons arising from Larmor precession was found at the double-hump position, which results in high ion density. The target was etched seriously at the double-hump position due to the high ion density there. The data indicates that the increase in power can lead to a high sputtering speed rate.