Non-invasive Measurement System Research Articles

Evaluation of external pressure to the sacral region in the lithotomy position using the noninvasive pressure distribution measurement system.

BackgroundPressure ulcers (PUs) in the sacral region can be a complication of surgical procedures performed in the lithotomy position. Previous reports have noted a difference between men and women in PU development related to the supine position, and body weight and body mass index (BMI) have been also described as known risk factors in supine position-related PU development. The BIG-MAT® system is a noninvasive pressure distribution measurement device used to measure external pressure (EP). We used this system to investigate the relationship between EP to the sacral region in the lithotomy position and selected physical characteristics.MethodsWe recruited 21 young, healthy volunteers (11 men and 10 women, aged 21.4±0.5 years). Using the BIG-MAT system, we measured four types of EP to the sacral region: box pressure, peak box pressure, contact pressure, and peak contact pressure. We analyzed the relationships between these dynamic parameters and physical characteristics of the participants.ResultsThere were no differences between men and women in the four types of EP, and no significant differences related to the participants’ height, weight, or BMI.ConclusionAn individual’s height, weight, and BMI may not contribute to the risk of inducing lithotomy position-related PUs in the sacral region. The noninvasive pressure distribution measurement system BIG-MAT for patients in the lithotomy position during surgery could become a significant device when estimating EP at the sacral region.

Non-invasive individual methane measurement in dairy cows

Attempts to lower the environmental footprint of milk production needs a sound understanding of the genetic and nutritional basis of methane (CH4) emissions from the dairy production systems. This in turn requires accurate and reliable techniques for the measurement of CH4 output from individual cows. Many of the available measurement techniques so far are either slow, expensive, labor intensive and are unsuitable for large-scale individual animal measurements. The main objectives of this study were to examine and validate a non-invasive individual cow CH4 measurement system that is based on photoacoustic IR spectroscopy (PAS) technique implemented in a portable gas analysis equipment (F10), referred to as PAS-F10 method and to estimate the magnitude of between-animal variations in CH4 output traits. Data were collected from 115 Nordic Red cows of the Minkiö experimental dairy farm, at the Natural Resources Institute Finland (Luke). Records on continuous daily measurements of CH4, milk yield, feed intake and BW measurements over 2 years period were compiled for data analysis. The daily CH4 output was calculated using carbon dioxide as a tracer method. Estimates from the non-invasive PAS-F10 technique were then tested against open-circuit indirect respiration calorimetric chamber measurements and against estimates from other widely used prediction models. Concordance analysis was used to establish agreement between the chamber and PAS-F10 methods. A linear mixed model was used for the analysis of the large continuous data. The daily CH4 output of cows was 555 l/day and ranged from 330 to 800 l/day. Dry matter intake, level of milk production, lactation stage and diurnal variation had significant effects on daily CH4 output. Estimates of the daily CH4 output from PAS-F10 technique compared relatively well with the other techniques. The concordance correlation coefficient between combined weekly CH4 output estimates of PAS-F10 and chamber was 0.84 with lower and upper confidence limits of 0.65 and 0.93, respectively. Similarly, when chamber CH4 measurements were predicted from PAS-F10 measurements, the mean of two separate weekly PAS-F10 measurements gave the lowest prediction error variance than either of the separate weekly PAS-F10 measurements alone. This suggests that every other week PAS-F10 measurements when combined would improve the estimation of CH4 output with PAS-F10 technique. The repeatability of daily CH4 output from PAS-F10 technique ranged from 0.40 to 0.46 indicating that some between-animal variation exist in CH4 output traits.

A Pilot Study Measuring Aluminum in Bone in Alzheimer's Disease and control Subjects Using in vivo Neutron Activation Analysis.

Aluminum, being the most abundant metal in the earth's crust, is widely distributed in the environment, and is routinely taken up by the human body through ingestion and inhalation. Aluminum is not considered an essential element and it can be toxic in high concentrations. Most of the body burden of aluminum is stored in the bones. Aluminum has been postulated to be involved in the causality of Alzheimer's disease. A system for non-invasive measurement of bone aluminum using the in vivo neutron activation analysis technique has been developed and previously reported in the literature by our group. The results are reported as ratio of Al to Ca in order to eliminate the variations in beam parameters and geometry as well as the physical variations among the subjects such as size of the hand and bone structure. This pilot study included 30 subjects, 15 diagnosed with Alzheimer's disease in mild and moderate stages and 15 control subjects, all of whom were 60 years of age or older. The mean value of aluminum for the control group was 2.7±8.2μg Al/g Ca (inverse-variance weighted mean 3.5±0.9μg Al/g Ca) and for the Alzheimer's disease subjects was 12.5±13.1μg Al/g Ca (inverse-variance weighted mean 7.6±0.6μg Al/g Ca). The difference between the mean of the Alzheimer's disease group and the mean of the control group was 9.8±15.9μg Al/g Ca, with a p-value of 0.02. An age-dependent linear increase in bone aluminum concentration was observed for all subjects. The difference in serum aluminum levels between the two groups did not reach significance.

Impedimetric real-time monitoring of neural pluripotent stem cell differentiation process on microelectrode arrays

In today's neurodevelopment and -disease research, human neural stem/progenitor cell-derived networks represent the sole accessible in vitro model possessing a primary phenotype. However, cultivation and moreover, differentiation as well as maturation of human neural stem/progenitor cells are very complex and time-consuming processes. Therefore, techniques for the sensitive non-invasive, real-time monitoring of neuronal differentiation and maturation are highly demanded.Using impedance spectroscopy, the differentiation of several human neural stem/progenitor cell lines was analyzed in detail. After development of an optimum microelectrode array for reliable and sensitive long-term monitoring, distinct cell-dependent impedimetric parameters that could specifically be associated with the progress and quality of neuronal differentiation were identified. Cellular impedance changes correlated well with the temporal regulation of biomolecular progenitor versus mature neural marker expression as well as cellular structure changes accompanying neuronal differentiation. More strikingly, the capability of the impedimetric differentiation monitoring system for the use as a screening tool was demonstrated by applying compounds that are known to promote neuronal differentiation such as the γ-secretase inhibitor DAPT.The non-invasive impedance spectroscopy-based measurement system can be used for sensitive and quantitative monitoring of neuronal differentiation processes. Therefore, this technique could be a very useful tool for quality control of neuronal differentiation and moreover, for neurogenic compound identification and industrial high-content screening demands in the field of safety assessment as well as drug development.

Distinct effect of pH on N uptake and assimilation in two conifer species

Prince Rupprecht’s Larch from the Loess Plateau takes up and assimilates a greater proportion of N as NO , particularly at neutral pH, whereas Chinese Fir assimilates a greater proportion of N as NH , particularly at low pH levels. The effects of pH on nitrate and ammonium uptake and assimilation in two coniferous species were compared. Prince Rupprecht’s Larch (Larix principis-rupprechtii Mayr) grows on the loess plateau in alkaline soils with low available nitrogen (N), whereas Chinese Fir (Cunninghamia lanceolata) grows in acidic soils. In the present study, the net fluxes in ammonium (NH4 +) and nitrate (NO 3 ) were measured using a non-invasive microelectrode ion flux measurement system, and the expression of NH4 + and NO 3 transporters (AMTs and NRTs, respectively) as well as H+-ATPase was examined to provide insights into the N uptake mechanisms in Prince Rupprecht’s Larch and Chinese Fir. The enzyme assays involved in N assimilation were also determined. For Prince Rupprecht’s Larch, low pH (pH 4) resulted in a decrease in net ammonium uptake, which remained unchanged in Chinese Fir. Net nitrate uptake in Prince Rupprecht’s Larch and Chinese Fir was much lower in soils with pH 4 relative to those with pH 7. Low pH significantly decreased the H+-ATPase activity and the expression level of NRTs in roots of Prince Rupprecht’s Larch. However, the expression level of AMTs in Prince Rupprecht’s Larch was significantly higher at pH 7 than at pH 4. The H+-ATPase activity in roots of Chinese Fir remained unaltered in response to changes in pH, and the transcript abundances of AMTs and NRTs were down-regulated by low pH. Low pH decreased N assimilation in both conifer species with the exception of NH4 + assimilation in Chinese Fir, which displayed higher glutamine synthetase (GS) and glutamate synthetase (GOGAT activities) at low pH. Prince Rupprecht’s Larch from the Loess Plateau takes up and assimilates a greater proportion of N as NO 3 , particularly at neutral pH, whereas Chinese Fir assimilates a greater proportion of N as NH4 +, particularly at low pH levels. This study contributes to our understanding of nitrogen metabolism mechanisms in response to pH changes.

Differences between clinical “snap-shot” and “real-life” assessments of lumbar spine alignment and motion – What is the “real” lumbar lordosis of a human being?

The individual lumbar lordosis and lumbar motion have been identified to play an important role in pathogenesis of low back pain and are essential references for preoperative planning and postoperative evaluation. The clinical “gold-standard” for measuring lumbar lordosis and its motion are radiological “snap-shots” taken while standing and during upper-body flexion and extension. The extent to which these clinically assessed values characterise lumbar alignment and its motion in daily life merits discussion.A non-invasive measurement-system was employed to measure lumbar lordosis and lumbar motion in 208 volunteers (age: 20–74yrs; ♀/♂: 115/93). For an initial short-term measurement, comparable with the clinical “snap-shot”, lumbar lordosis and its motion were assessed while standing and during flexion and extension. Subsequently, volunteers were released to their daily lives while wearing the device, and measurements were performed during the following 24h.The average lumbar lordosis during 24h (8.0°) differed significantly from the standardised measurement while standing (33.3°). Ranges of motion were significantly different throughout the day compared to standing measurements. The influence of the factors age and gender on lordosis and its motion resulted in conflicting results between long- and short-term-measurements.In conclusion, results of short-term examinations differ considerably from the average values during real-life. These findings might be important for surgical planning and increase the awareness of the biomechanical challenges that spinal structures and implants face in real-life. Furthermore, long-term assessments of spinal alignment and motion during daily life can provide valid data on spinal function and can reveal the importance of influential factors.

Non-destructive mobile monitoring of microbial contaminations on meat surfaces using porphyrin fluorescence intensities

A non-destructive mobile system for meat quality monitoring was developed and investigated for the possible application along the whole production chain of fresh meat. Pork and lamb meat was stored at 5°C for up to 20days post mortem and measured with a fluorescence spectrometer. Additionally, the bacterial influence on the fluorescence signals was evaluated by different experimental procedures. Fluorescence of NADH and different porphyrins could be correlated to the growth of diverse bacteria and hence used for contamination monitoring. The increase of porphyrin fluorescence started after 9days p.m. for pork and after 2days p.m. for lamb meat. Based on the results, a mobile fluorescence system was built and compared with the laboratory system. The corrected function of the meat slices showed a root mean square error of 1156.97 r.u. and a mean absolute percentage error of 12.59%; for lamb the values were 470.81 r.u. and 15.55%, respectively. A mobile and non-invasive measurement system would improve the microbial security of fresh meat.

Fast Experimental Energy Characterization of a Controlled Rotary Axis

The goal of the paper is to present a methodology and the related instrumentation for fast energy characterization of industrial machines. Standard energy measurements prescribe acquiring power flowing into the system and into every significant subsystem of the machine using a considerable number of power meters (or repeated measurements) that determine high installation times, costs and efforts. Often, such measurements are missing additional information about machine activity, needed to understanding energy dissipations. Fast experimental characterization method proposed in the paper assumes to measure solely the total power absorbed by the machine and to estimate the consumptions of machine subsystems by acquiring additional signals, e.g. states and variables, via a newly developed wireless, non-invasive measurement system. Knowledge of these states allows to create an intermediate-precision energy models of the system. A case study is performed to identify and analyse such model of axis in an industrial robot. Apart from power, two additional signals are acquired: axis acceleration via accelerometer and current of one of the motor phases, using a current transducer. Techniques of sensor data fusion are employed to obtain more reliable results. Axis energy models are identified and compared to find the best match for the considered application.

Noninvasive blood glucose measurement utilizing a newly designed system based on modulated ultrasound and infrared light

The approach of a new noninvasive innovation for blood glucose measurement will reform management of diabetes alongside expanded patient compliance, decline load on therapeutic crisis, and diabetes associated complications. In this present work, we represent a modulated ultrasound and infrared technique-based noninvasive system for blood glucose measurement over human subjects. The oral glucose tolerance test- and random blood glucose level test-based clinical study was performed over human subjects to measure the performance of our indigenously designed system. The accuracy was examined by pairing and comparing our noninvasive predicted data with the invasive reference data. The oral glucose tolerance test and random blood glucose test produced a total of 180 and 30 paired glucose values (noninvasive vs. invasive), respectively. The root mean squared error between the noninvasive and invasive glucose value for oral glucose tolerance test and random blood glucose measurement was 23.76 mg/dl and 28.20 mg/dl, respectively. The Pearson correlation coefficient between the noninvasive and invasive glucose value for both the tests was 0.76 and 0.85, respectively. Similarly, the mean absolute error for both the tests was 15.92 mg/dl and 17.76 mg/dl, respectively. Further, the Clarke Error Grid analysis depicts that both the tests result occupy medically accurate and acceptable zones A and B, respectively (oral glucose tolerance test: zone A = 78.33 %; zone B = 21.66 % and random blood glucose measurement: zone A = 83.33 %; zone B = 16.66 %). Hence, the present study direct towards the potentiality of our technique for noninvasive blood glucose measurement. The instrument was medically safe and well tolerated.

AN EMBEDDED SYSTEM FOR NON-INVASIVE BLOOD GLUCOSE MEASUREMENT IN GLUCOSE TOLERANCE TEST

Diabetic patients need to monitor their blood glucose levels frequently to prevent complications related to the disease. Commonly used glucose measurement methods are invasive, uncomfortable, and usually require frequent finger pricking. This paper deals with the development of a non-invasive system for continuous measurement of blood glucose concentration levels, using near infrared light of suitable wavelength. Glucose determination using near infrared can be done by taking measurement of transmitted light through human body. This device may become very useful while conducting glucose tolerance test (GTT). In glucose tolerance test, patient should be given a measured dose of glucose solution to drink and blood is drawn at intervals of half an hour or one hour for two to four hours. This requires five to nine finger pricking for measurement of glucose concentration. By using this proposed device pricking can be reduced to one. First the glucose concentration is measured using conventional method for calibration. Then by comparing with the first sample measurement subsequent values can be determined without further pricking.

Noninvasive ambulatory measurement system of cardiac activity.

This work implements a noninvasive system that measures the movements caused by cardiac activity. It uses unobtrusive Electro-Mechanical Films (EMFi) on the seat and on the backrest of a regular chair. The system detects ballistocardiogram (BCG) and respiration movements. Real data was obtained from 54 volunteers. 19 of them were measured in the laboratory and 35 in a hospital waiting room. Using a BIOPAC acquisition system, the ECG was measured simultaneously to the BCG for comparison. Wavelet Transform (WT) is a better option than Empirical Mode Decomposition (EMD) for signal extraction and produces higher effective measurement time. In the laboratory, the best results are obtained on the seat. The correlation index was 0.9800 and the Bland-Altman limits of agreement were 0.7136 ± 4.3673 [BPM]. In the hospital waiting room, the best results are also from the seat sensor. The correlation index was 0.9840, and the limits of agreement were 0.4386 ± 3.5884 [BPM]. The system is able to measure BCG in an unobtrusive way and determine the cardiac frequency with high precision. It is simple to use, which means the system can easily be used in non-standard settings: resting in a chair or couch, at the gym, schools or in a hospital waiting room, as shown.

Research on Subcutaneous Pulse Shape Measurement by Near-infrared Moiré Technique

A pulse is generated when the heart pumps blood into the arterial system. The heart pumps blood only when it contracts, not when it relaxes; therefore, blood enters the arterial system in a cyclical form. Artery beating is visible in some parts of the body surface, such as the radial artery of the wrist. This paper mainly uses the feature in which near-infrared spectroscopy penetrates skin to construct a non-invasive measurement system that can measure small vibration in the subcutaneous tissue of the human body, and then uses it for the pulse measurement. This measurement system uses the optical moir<TEX>$\acute{e}$</TEX> principle, together with the fringe displacement made by small vibration in the subcutaneous tissue, and an image analysis program to calculate the height variation from small vibrations in the subcutaneous tissue. It completes a measurement system that records height variation with time, and that together with a fast Fourier transform (FFT) program, they can convert the pulse waveform generated by vibration (time-amplitude) to heartbeat frequency (frequency-amplitude). This is a new and non-invasive medical assistance system for measuring the pulse of the human body, with the advantages of being simple, fast, safe and objective.

Towards a smart non-invasive fluid loss measurement system.

In this article, a smart wireless sensing non-invasive system for estimating the amount of fluid loss, a person experiences while physical activity is presented. The system measures three external body parameters, Heart Rate, Galvanic Skin Response (GSR, or skin conductance), and Skin Temperature. These three parameters are entered into an empirically derived formula along with the user's body mass index, and estimation for the amount of fluid lost is determined. The core benefit of the developed system is the affluence usage in combining with smart home monitoring systems to care elderly people in ambient assisted living environments as well in automobiles to monitor the body parameters of a motorist.

Corrigendum to Comparative Study of different Measurement Sites Using NIR Based Non-invasive Glucose Measurement System

Corrigendum to Comparative Study of different Measurement Sites Using NIR Based Non-invasive Glucose Measurement System

Comparative Study of Different Measurement Sites Using NIR Based Non-invasive Glucose Measurement System

Abstract In Diabetes, self-monitoring of blood glucose is crucial for effective treatment since it can help to identify and prevent unwanted episodes of hypoglycemia and hyperglycemia. Aim of the present work is to design and develop a non invasive gluco-meter using near infrared LED (940 nm). Three different designs of probes (arm, finger and ear lobe) were fabricated to measures in-vivo blood glucose. In addition, we also carried out experiments to study the interaction with glucose molecules in solution under plane polarized light. The polarizers were used at three different angles(450, 900 and 1800) to know the behavior of glucose interaction with polarized light of 640 nm and 740 nm with varying concentration of glucose in the solution. The polarization results showed that at 1800 the glucose has maximum polarization (1.12) and at 900 and 450 it has comparatively less polarization values 0.9 and 0.35 respectively. The polarization results helped us to design the probes. Therefore, we placed photodiodes at three angles (450, 900 and 1800). The results as expected were better at 1800 by showing maximum variation in photodiode voltage output. The results were in the correlation of the polarization studies. A comparative study of three measurement sites has also been carried out. The primary result of current sensor system is promising and with further improvement a robust system for glucose sensing can be realized.

FIve-band microwave radiometer system for non-invasive measurement of deep brain temperatures in newborn infants: accruracy and challenge

FIve-band microwave radiometer system for non-invasive measurement of deep brain temperatures in newborn infants: accruracy and challenge

F124 LEDによる光誘起蛍光法に基づく温度場の非接触計測手法の実験的性能評価(OS-02:多孔質体内の伝熱・流動現象とその応用(2))

We develop a non-invasive measurement system based on fluorescence. The development of the system arises from the investigations of heat transfer characteristics of thermal energy storage and magnetic refrigeration. We use a light emitting diode (LED) as a light source instead of a laser. In order to evaluate the measurement feasibility and performance, an experiment was carried out using a heated test section filled with fluid. The test section was carefully designed based on the critical Rayleigh number, so that the heat transfer in the section would be dominated by conductive heat transfer only. Spatial temperature distribution was obtained by converting the fluorescence irradiance to temperature through calibration data. The initial result exhibited the expected monotonic temperature distribution in the test section and the feasibility of the temperature measurement based on the LED-induced fluorescence (LEDIF) was confirmed.

Abdominal oxygen saturation for monitoring return of spontaneous circulation in out-of-hospital cardiac arrest using near infrared spectrophometry

AimWe used near-infrared spectrophotometry to assess the initial and final abdominal and cerebral saturations during cardiopulmonary resuscitation (CPR) of patients with out-of-hospital cardiac arrest to determine if there is a correlation between increase in these saturation values and return of spontaneous circulation. Materials and methodsWe evaluated 34 patients with out-of-hospital cardiac arrest without witnesses brought to our emergency department. Abdominal and cerebral saturations were measured using near-infrared spectrophotometry from the start of CPR. Cardiopulmonary resuscitation was performed for a maximum of 30 minutes. The effect of abdominal saturations in patients with or without spontaneous circulation restored through CPR was then assessed. ResultsThirty-four patients (17 males + females) with a mean age of 63.06 ± 11.66 years were included in the study. A significant correlation was determined between increase in abdominal saturations measured at the start and end of CPR and the return of spontaneous circulation (P < .001). A good positive correlation was also identified between abdominal saturation and return of spontaneous circulation. ConclusionPatients with increased abdominal and cerebral saturation values have a higher survival rate after appropriate CPR. This noninvasive measurement system and monitoring of patients during CPR may be a good method of predicting return of spontaneous circulation and assessing abdominal perfusion.

Evaluation of a novel noninvasive continuous core temperature measurement system with a zero heat flux sensor using a manikin of the human body.

Reliable continuous perioperative core temperature measurement is of major importance. The pulmonary artery catheter is currently the gold standard for measuring core temperature but is invasive and expensive. Using a manikin, we evaluated the new, noninvasive SpotOn™ temperature monitoring system (SOT). With a sensor placed on the lateral forehead, SOT uses zero heat flux technology to noninvasively measure core temperature; and because the forehead is devoid of thermoregulatory arteriovenous shunts, a piece of bone cement served as a model of the frontal bone in this study. Bias, limits of agreements, long-term measurement stability, and the lowest measurable temperature of the device were investigated. Bias and limits of agreement of the temperature data of two SOTs and of the thermistor placed on the manikin's surface were calculated. Measurements obtained from SOTs were similar to thermistor values. The bias and limits of agreement lay within a predefined clinically acceptable range. Repeat measurements differed only slightly, and stayed stable for hours. Because of its temperature range, the SOT cannot be used to monitor temperatures below 28°C. In conclusion, the new SOT could provide a reliable, less invasive and cheaper alternative for measuring perioperative core temperature in routine clinical practice. Further clinical trials are needed to evaluate these results.

Verifying the Melting Behavior in Single-Screw Plasticization Units Using a Novel Simulation Model and Experimental Method

Abstract We report on the development of a novel non-invasive ultrasonic measurement system for determining the melting behavior in a single-screw plasticization unit (35/22D) and on a modified drag-induced melt removal model that builds upon that by Tadmor and Gogos (2006). The solid bed to melt pool ratio is quantified using a non-invasive ultrasonic system based on reflection measurements. Automated analysis of the reflected pulses – measured at different axial positions along the barrel – allows the melting process to be monitored online. Our analysis of the delay section incorporates viscous dissipation into Tadmor's drag-induced melt removal model. We link temperature profile and melt film thickness via differential equations and consider viscous dissipation. By segmenting the delay section in the axial direction, the temperature dependency of the thermo-physical material properties is also considered. Using the melting behavior measured for different materials, we verified the mathematical model. Additionally, the effect of reduced screw length on the plasticization process, important for the injection molding process, was investigated.