Near-infrared Spectroscopy Sensor Research Articles

Abstract TP65: Evaluation Of Leg Microvascular Function In Chronic Stroke Survivors Using Near Infrared Spectroscopy And The Vascular Occlusion Technique.

Background: Chronic stroke survivors have impaired conduit artery endothelial function, but little is known about peripheral microvascular function post-stroke. Near infrared spectroscopy (NIRS) can non-invasively measure tissue oxygen saturation (StO 2 ) of skeletal muscle, and when combined with a dynamic challenge like a vascular occlusion, can indirectly evaluate tissue oxygen utilization during the occlusion period and microvascular function during the post-occlusive hyperemic period. We hypothesized that microvascular function would be impaired in the tibialis anterior (TA) muscle of the affected leg of chronic stroke survivors compared to the non-affected leg as evidenced by a slower oxygen resaturation rate post-cuff release. Methods: Fifteen chronic stroke survivors completed this study. The mean age was 57±12 years, 10 were female, and the mean time since stroke was 12±10 years. After resting for fifteen minutes a NIRS sensor was placed over either the affected or non-affected TA. The opposite leg was tested one week later. After recording five minutes of baseline StO 2 , a cuff was placed around the proximal thigh and inflated to 225 mmHg for five minutes. StO 2 was continuously measured during cuff inflation and for five minutes post-cuff release. The rate of change in StO 2 was calculated during the five-minute cuff occlusion and the first 12 seconds post-cuff release. Results: There was no difference in baseline StO 2 between the affected and non-affected TA (68±11% vs. 67±6%, respectively; p=0.60). There was also no difference in the change in StO 2 during the occlusion period (affected ΔStO 2 = -31±12 % vs. non-affected -35±19%; p=0.76), or the rate of oxygen desaturation (affected -0.15±0.11 %·s -1 vs non-affected -0.10±0.04 %·s -1 ; p=0.39). After cuff release, there was a greater oxygen resaturation rate in the non-affected leg compared to the affected leg (3.13±2.08 %·s -1 vs. 1.60±1.11 %·s -1 , respectively; p=0.01). Conclusion: There was no difference in oxygen utilization between the affected and non-affected TA during the cuff occlusion period. The oxygen resaturation response in the affected TA post-cuff release was slower compared to the non-affected TA, suggesting microvascular function is impaired in the affected muscle.

Accurate identification of the geographical origins of lily using near-infrared spectroscopy combined with carbon dot-tetramethoxyporphyrin nanocomposite and chemometrics

Near-infrared spectroscopy technique is a prevailing tool for quality control of foods and traditional Chinese medicines. However, it usually faced the problems of severe peak overlap, low classification accuracy and poor specificity. In this work, the potential of carbon dot-tetramethoxyporphyrin nanocomposite-based nano-effect near-infrared spectroscopy sensor combined with chemometric method was investigated for the accurate identification lily from different geographical origins. Partial least squares-discriminant analysis (PLS-DA) was used for differentiating geographical origins of lily based on the collected traditional and nano-effect near-infrared spectroscopy. Compared with traditional near-infrared spectroscopy, the nano-effect near-infrared spectroscopy obtains superior classification performance with 100% accuracy on the training and test set. The results showed that the proposed method based on near-infrared spectroscopy combined with nanocomposites and chemometrics could be considered as a promising tool for rapid discrimination of the authenticity of food and traditional Chinese medicine in the future.

Assessment of Muscle Fatigue Based on Motor Unit Firing, Muscular Vibration and Oxygenation via Hybrid Mini-Grid sEMG, MMG, and NIRS Sensing

It is vital to measure muscular fatigue for human-machine interaction (HMI) and avoiding muscle impairment. This paper presents a novel approach to comprehensively evaluate muscle fatigue through the fusion of mini-grid surface electromyography (sEMG), mechanomyography (MMG) and near-infrared spectroscopy (NIRS). A hybrid mini-grid sEMG, MMG and NIRS sensor system was developed, forming an instrument to measure motor unit action potential trains (MUAPt), low-frequency myofiber vibration and oxygen metabolism. Muscle fatigue induced experiment was performed via a sustained isometric contraction at 50% of maximal voluntary contraction (MVC) force with ten subjects. MUAPts were decomposed from the four-channel array of sEMG signals, and the firing rate of specific MUs was calculated to measure fatigue process. Furthermore, root mean square (RMS) and median frequency (MDF) of sEMG/MMG, blood volume (BV) and muscle oxygenation (△HbO₂) extracted from NIRS, were proposed as fatigue metrics. The variation and correlation analysis among fatigue metrics provided a detailed and reliable physiological assessment on muscle fatigue, gaining a synthetical understanding of muscle fatigue mechanisms. The outcomes of this study have great potential applications in sports, clinical diagnosis and HMI.

Performance Assessment of a Commercial Continuous-Wave Near-Infrared Spectroscopy Tissue Oximeter for Suitability for Use in an International, Multi-Center Clinical Trial.

Despite the wide range of clinical and research applications, the reliability of the absolute oxygenation measurements of continuous wave near-infrared spectroscopy sensors is often questioned, partially due to issues of standardization. In this study, we have compared the performances of 13 units of a continuous wave near-infrared spectroscopy device (PortaMon, Artinis Medical Systems, NL) to test their suitability for being used in the HEMOCOVID-19 clinical trial in 10 medical centers around the world. Detailed phantom and in vivo tests were employed to measure the precision and reproducibility of measurements of local blood oxygen saturation and total hemoglobin concentration under different conditions: for different devices used, different operators, for probe repositioning over the same location, and over time (hours/days/months). We have detected systematic differences between devices when measuring phantoms (inter-device variability, <4%), which were larger than the intra-device variability (<1%). This intrinsic variability is in addition to the variability during in vivo measurements on the forearm muscle resulting from errors in probe positioning and intrinsic physiological noise (<9%), which was also larger than the inter-device differences (<3%) during the same test. Lastly, we have tested the reproducibility of the protocol of the HEMOCOVID-19 clinical trial; that is, forearm muscle oxygenation monitoring during vascular occlusion tests over days. Overall, our conclusion is that these devices can be used in multi-center trials but care must be taken to characterize, follow-up, and statistically account for inter-device variability.

A Wireless Near-Infrared Spectroscopy Device for Flap Monitoring: Proof of Concept in a Porcine Musculocutaneous Flap Model.

Current near-infrared spectroscopy (NIRS)-based systems for continuous flap monitoring are highly sensitive for detecting malperfusion. However, the clinical utility and user experience are limited by the wired connection between the sensor and bedside console. This wire leads to instability of the flap-sensor interface and may cause false alarms. We present a novel wearable wireless NIRS sensor for continuous fasciocutaneous free flap monitoring. This waterproof silicone-encapsulated Bluetooth-enabled device contains two light-emitting diodes and two photodetectors in addition to a battery sufficient for 5 days of uninterrupted function. This novel device was compared with a ViOptix T.Ox monitor in a porcine rectus abdominus myocutaneous flap model of arterial and venous occlusions. Devices were tested in four flaps using three animals. Both devices produced very similar tissue oxygen saturation (StO2) tracings throughout the vascular clamping events, with obvious and parallel changes occurring on arterial clamping, arterial release, venous clamping, and venous release. Small interdevice variations in absolute StO2 value readings and magnitude of change were observed. The normalized cross-correlation at zero lag describing correspondence between the novel NIRS and T.Ox devices was >0.99 in each trial. The wireless NIRS flap monitor is capable of detecting StO2 changes resultant from arterial vascular occlusive events. In this porcine flap model, the functionality of this novel sensor closely mirrored that of the T.Ox wired platform. This device is waterproof, highly adhesive, skin conforming, and has sufficient battery life to function for 5 days. Clinical testing is necessary to determine if this wireless functionality translates into fewer false-positive alarms and a better user experience.

SCALING UP SAGEBRUSH CHEMISTRY WITH NEAR-INFRARED SPECTROSCOPY AND UAS-ACQUIRED HYPERSPECTRAL IMAGERY

Abstract. Sagebrush ecosystems (Artemisia spp.) face many threats including large wildfires and conversion to invasive annuals, and thus are the focus of intense restoration efforts across the western United States. Specific attention has been given to restoration of sagebrush systems for threatened herbivores, such as Greater Sage-Grouse (Centrocercus urophasianus) and pygmy rabbits (Brachylagus idahoensis), reliant on sagebrush as forage. Despite this, plant chemistry (e.g., crude protein, monoterpenes and phenolics) is rarely considered during reseeding efforts or when deciding which areas to conserve. Near-infrared spectroscopy (NIRS) has proven effective in predicting plant chemistry under laboratory conditions in a variety of ecosystems, including the sagebrush steppe. Our objectives were to demonstrate the scalability of these models from the laboratory to the field, and in the air with a hyperspectral sensor on an unoccupied aerial system (UAS). Sagebrush leaf samples were collected at a study site in eastern Idaho, USA. Plants were scanned with an ASD FieldSpec 4 spectroradiometer in the field and laboratory, and a subset of the same plants were imaged with a SteadiDrone Hexacopter UAS equipped with a Rikola hyperspectral sensor (HSI). All three sensors generated spectral patterns that were distinct among species and morphotypes of sagebrush at specific wavelengths. Lab-based NIRS was accurate for predicting crude protein and total monoterpenes (R2 = 0.7–0.8), but the same NIRS sensor in the field was unable to predict either crude protein or total monoterpenes (R2 &lt; 0.1). The hyperspectral sensor on the UAS was unable to predict most chemicals (R2 &lt; 0.2), likely due to a combination of too few bands in the Rikola HSI camera (16 bands), the range of wavelengths (500–900 nm), and small sample size of overlapping plants (n = 28–60). These results show both the potential for scaling NIRS from the lab to the field and the challenges in predicting complex plant chemistry with hyperspectral UAS. We conclude with recommendations for next steps in applying UAS to sagebrush ecosystems with a variety of new sensors.

Renal tissue oxygenation after caffeine administration in preterm neonates.

Caffeine has been associated with reduced rates of acute kidney injury (AKI) in preterm neonates. The effect of caffeine on preterm neonatal renal regional saturation of oxygen (RrSO2) is unknown. RrSO2 was recorded continuously in neonates < 32 weeks' gestation until 7 days of age with INVOS™ neonatal near-infrared spectroscopy (NIRS) sensors. Baseline RrSO2 values were established by averaging the saturations in the 20 min prior to caffeine administration. Subgroup analysis was performed based on pre-caffeine RrSO2 averages. Change in RrSO2 was recorded at 0.5, 1, 2, 3, 4, 6, and 12 h after maintenance caffeine administration. Of 35 eligible neonates, 31 (median gestational age 28.4 weeks) received 156 caffeine doses (median 8 mg/kg). Analysis of combined doses showed no significant changes in RrSO2 after caffeine administration at any time. However, neonates with baseline 20-29.9% had significant increases from 1 to 12 h (range of increase 5.9-13.9%), and those with baseline 30-39.9 had significant increases at 1 h (8.06%, p < 0.05). Maintenance caffeine dosing increased RrSO2 in neonates with low RrSO2 in the first week. Further research is needed to determine the effect of loading doses of caffeine and if increases in RrSO2 correlate with improved clinical kidney outcomes. Caffeine administration is associated with increased renal tissue oxygenation in preterm neonates with low baseline values under 40%. The most significant renal tissue oxygenation changes occur in the first 3 h after IV caffeine administration. With recent studies suggesting low RrSO2 values in preterm neonates are associated with AKI, caffeine should be studied as a potential therapeutic for this common and complex morbidity in preterm neonates.

Persons with type 1 diabetes have low blood oxygen levels in the supine and standing body positions

IntroductionBlood oxygen saturation is low compared with healthy controls (CONs) in the supine body position in individuals with type 1 diabetes (T1D) and has been associated with complications. Since most...

Cerebral autoregulation in infants during sevoflurane anesthesia for craniofacial surgery.

Data on cerebral pressure-flow autoregulation in the youngest children are scarce. We studied the correlation between mean arterial pressure and cerebral tissue oxygen saturation (rSO2 ) by near-infrared spectroscopy (NIRS) in patients undergoing nose, lip, and palate surgery. We tested the hypothesis that cerebral pressure-flow autoregulation is impaired in children less than 1year undergoing surgery and general anesthesia with sevoflurane under controlled mechanical ventilation. After approval from the Ethical board, 15 children aged <1year were included. Before anesthesia induction, a NIRS sensor (INVOSTM , Medtronic, Minneapolis, USA) was placed over the cerebral frontal lobe. Frontal rSO2 , a surrogate for cerebral perfusion, mean arterial pressure, end-tidal CO2 - and sevoflurane concentration, and arterial oxygen saturation were sampled every minute after the induction. A repeated measures correlation analysis was performed to study correlation between mean arterial pressure and cerebral rSO2 , and the repeated measures correlation coefficient (rrm ) was calculated. Fifteen patients, aged 7.7±1.9months, were studied. rSO2 showed a positive correlation with mean arterial pressure ([95% CI: 9.0-12.1], P<0.001) with a moderate to large effect size (rrm =0.462), indicating an impaired cerebral pressure-flow autoregulation. The slopes of the rSO2 -mean arterial pressure correlations were steeper in patients who were hypotensive (mean arterial pressure <50mm Hg) compared to patients having a mean arterial pressure ≥50mm Hg, indicating that at lower mean arterial pressure, the cerebral pressure dependence of cerebral oxygenation is even more pronounced. During sevoflurane anesthesia in the youngest pediatric patients, cerebral perfusion is pressure-dependent, suggesting that the efficiency of the cerebral blood flow autoregulation is limited.

Near-Infrared Spectroscopy (NIRS) and Optical Sensors for Estimating Protein and Fiber in Dryland Mediterranean Pastures

Dryland pastures provide the basis for animal sustenance in extensive production systems in Iberian Peninsula. These systems have temporal and spatial variability of pasture quality resulting from the diversity of soil fertility and pasture floristic composition, the interaction with trees, animal grazing, and a Mediterranean climate characterized by accentuated seasonality and interannual irregularity. Grazing management decisions are dependent on assessing pasture availability and quality. Conventional analytical determination of crude protein (CP) and fiber (neutral detergent fiber, NDF) by reference laboratory methods require laborious and expensive procedures and, thus, do not meet the needs of the current animal production systems. The aim of this study was to evaluate two alternative approaches to estimate pasture CP and NDF, namely one based on near-infrared spectroscopy (NIRS) combined with multivariate data analysis and the other based on the Normalized Difference Vegetation Index (NDVI) measured in the field by a proximal active optical sensor (AOS). A total of 232 pasture samples were collected from January to June 2020 in eight fields. Of these, 96 samples were processed in fresh form using NIRS. All 232 samples were dried and subjected to reference laboratory and NIRS analysis. For NIRS, fresh and dry samples were split in two sets: a calibration set with half of the samples and an external validation set with the remaining half of the samples. The results of this study showed significant correlation between NIRS calibration models and reference methods for quantifying pasture quality parameters, with greater accuracy in dry samples (R2 = 0.936 and RPD = 4.01 for CP and R2 = 0.914 and RPD = 3.48 for NDF) than fresh samples (R2 = 0.702 and RPD = 1.88 for CP and R2 = 0.720 and RPD = 2.38 for NDF). The NDVI measured by the AOS shows a similar coefficient of determination to the NIRS approach with pasture fresh samples (R2 = 0.707 for CP and R2 = 0.648 for NDF). The results demonstrate the potential of these technologies for estimating CP and NDF in pastures, which can facilitate the farm manager’s decision making in terms of the dynamic management of animal grazing and supplementation needs.

Quality evaluation of Keemun black tea by fusing data obtained from near-infrared reflectance spectroscopy and computer vision sensors

Keemun black tea is classified into 7 grades according to the difference in its quality. The appearance and flavour are crucial indicators of its quality. This research demonstrates a rapid grading method of jointly using near-infrared reflectance spectroscopy (NIRS) and computer vision systems (CVS) to evaluate the flavour and appearance quality of tea. A Bruker MPA Fourier Transform near-infrared spectrometer was used to record the spectrum of samples. A computer vision system was used to capture the image of tea leaves in an unobstructed manner. 80 tea samples for each grade were analyzed. The performance of four NIRS feature extraction methods (principal component analysis, local linear embedding, isometric feature mapping, and convolutional neural network (CNN)) was compared in this study. Histograms of six geometric features (leaf width, leaf length, leaf area, leaf perimeter, aspect ratio, and rectangularity) of different tea samples were used to describe their appearance. A feature-level fusion strategy was used to combine softmax and artificial neural networks (ANN) to classify NIRS and CVS features. The results indicated that for an individual NIRS signal, CNN achieved the highest classification accuracy with the softmax classification model. The histograms of the combined shape features indicated that when the softmax classification model was used, the classification accuracy was also higher than ANN. The fusion of NIRS and CVS features proved to be the optimal combination; the accuracy of calibration, validation and testing sets increased from 99.29%, 96.67% and 98.57% (when the optimal features from a single-sensor were used) to 100.00%, 99.29% and 100.00% (when features from multiple-sensors were used). This study revealed that the combination of NIRS and CVS features can be a useful strategy for classifying black tea samples of different grades.

Rice Freshness Identification Based on Visible Near-Infrared Spectroscopy and Colorimetric Sensor Array

In this work, two methods, which were visible near-infrared spectroscopy (VNIRS) and visible near-infrared spectroscopy combined with colorimetric sensor array (VNIRS-CSA), were used to identify the volatile compound changes of rice samples stored for 0 to 6 months. Principal component analysis (PCA), interval partial least squares (iPLS), and synergy interval partial least squares (SiPLS) were used for qualitative classification. A prediction model was established by linear discriminant analysis (LDA), which was compared with the traditional VNIRS detection technology. The results revealed that the VNIRS-CSA got better performance than VNIRS and exhibited a good result based on iPLS/SiPLS-PCA/LDA models. Furthermore, spectral data from VNIRS-CSA were the best for LDA with a high prediction value of 0.925 after standard normal variate (SNV) processing and variable selection by SiPLS. The research demonstrated that VNIRS-CSA is a quick, accurate, and non-destructive method for monitoring the storage time of rice. The strategy also has the potential for volatile organic components analysis.

Young healthy adults with a family history of hypertension have increased microvascular reactivity but decreased macrovascular function.

To determine whether, like hypertensives, normotensive adults with a family history of hypertension (+FHH) display lower microvascular reactivity and conduit artery function than normotensive adults without a family history of hypertension (-FHH). A forearm vascular occlusion test was performed on healthy normotensive adults while resting in the supine position. A near-infrared spectroscopy sensor placed on the forearm measured skeletal muscle oxygen saturation kinetics to determine microvascular reactivity. Simultaneously, an ultrasound probe placed on the brachial artery above the occlusion cuff was used to assess flow-mediated dilation; a test of macrovascular function. Twenty-two participants were included in this investigation (-FHH n=13, +FHH n=9). Following cuff release, the resaturation slope (1st 10s median±SD, -FHH 2.76±2.10, +FHH 5.59±2.47%/s; p=.036) was greater in +FHH when accounting for the magnitude and rate of the decrease in skeletal muscle oxygen saturation during occlusion. Conversely, flow-mediated dilation (median±SD, -FHH 5.96±5.22, +FHH 4.10±3.17%∆; p=.031) was lower in +FHH when accounting for baseline artery diameter and shear rate. Young +FHH adults have altered microvascular and macrovascular reactivity compared with young -FHH adults.

Non-destructive determination of fatty acid composition of in-shell and shelled almonds using handheld NIRS sensors

One of the major compounds in almond kernels, which determines their nutritional quality, are lipids. The aim of this research was to determine the fatty acid profile in intact in-shell and shelled almonds (145 samples) using two new generation handheld near infrared spectroscopy (NIRS) sensors, of different optical design and technical specifications, adapted for in situ analysis in different stages in the food supply chain: in the industry after harvest, at the reception points and during postharvest storage. For both instruments, two procedures for taking near infrared (NIR) spectra were tested: (1) static, where point spectral readings were taken of almonds placed on trays; (2) dynamic, where spectra were taken by scanning the entire trays. Modified partial least squares (MPLS) regression models were developed using NIR spectra with different combinations of signal pre-treatments — derivative and scatter correction methods. The residual predictive deviation for cross validation (RPDcv) of the best models developed for the prediction of palmitic, stearic, oleic, and linoleic acids using shelled almonds were 2.40, 2.16, 3.98, and 3.77, respectively, and 1.73, 1.73, 2.02, and 2.11 for the in-shell almonds. These results confirm the feasibility of NIRS technology to measure the fatty acid profile in in-shell and shelled almonds. A comparison between the presentation mode (in-shell or shelled) and analysis mode (static or dynamic) showed that the best results were obtained for shelled almonds analysed in dynamic mode.

Non-invasive continuous renal tissue oxygenation monitoring to identify preterm neonates at risk for acute kidney injury.

Near-infrared spectroscopy (NIRS) is an emerging tool to identify signs of inadequate tissue oxygenation in preterm neonates with acute kidney injury (AKI). Previous studies have shown a correlation between low renal tissue oxygenation (RrSO2) in the first 24hours of age and the later development of AKI. In this prospective clinical trial, NIRS monitoring was used to identify changes in RrSO2 in comparison to traditional AKI markers, serum creatinine (SCr), and urine output (UOP). We enrolled 35 preterm neonates born less than 32weeks' gestation and applied neonatal NIRS sensors at less than 48hours of age. Neonates underwent 7days of continuous monitoring. Renal and demographic information were collected for the first 7days of age. AKI was determined by the modified neonatal Kidney Disease: Improving Global Outcomes (KDIGO) definition including UOP. Three patients experienced AKI, all based on both SCr and UOP criteria. Each neonate with AKI had decreases in RrSO2 over 48hours prior to changes in SCr and UOP. Patients with AKI had lower median RrSO2 values compared to patients without AKI over the first week of age, (32.4% vs. 60%, p < 0.001). RrSO2 monitoring identified preterm neonates at risk for AKI. NIRS detected a decline in RrSO2 prior to changes in SCr and UOP and was significantly lower in patients with AKI compared to those without AKI. Further studies are needed to evaluate the ability of RrSO2 monitoring to detect signs of kidney stress prior to the diagnosis of AKI. Graphical abstract.

Near-Infrared Spectroscopy (NIRS) of Muscle HbO2 and MbO2 Desaturation During Exercise.

Continuous noninvasive monitoring of muscle oxygenation has important clinical applications for muscle disorders such as compartmentation syndrome, fibromyalgia, deep vein thrombosis, malignant hyperthermia, and the assessment of training in athletic performance. NIRS has precisely such potential and has been used to detect deep venous thrombosis, evaluate athletic performance, and assess limb reperfusion and revascularization. The aim of this study was to examine the relationship between muscle hemoglobin oxygen (HbO2) and myoglobin (MbO2) desaturation using NIRS combined with venous blood sampling and HbO2 desaturation during forearm muscle exercise. Eleven normal subjects were studied, with informed consent and an IRB-approved protocol. A NIRS sensor (INVOS4100, Somanetics, Corp.) was applied on the volar aspect of the forearm. The subjects exercised their forearm by clenching and relaxing their fist while observing the oximeter and driving the reading to specified levels from 90% to 15% (minimum possible reading). Venous blood samples were withdrawn for measurement of blood gases and oxygen saturation (IL-Co-Oximeter). RSO2 (%) vs VO2 Sat showed a two-component HbO2 desaturation suggesting representation of venous HbO2 desaturation and perhaps myoglobin oxygen (MBO2) desaturation. Subtraction of the linear venous HbO2 curve from the two-component curve suggests MbO2 desaturation at venous hemoglobin oxygen saturation of about 10-20%. Conclusions: The kinetics of desaturation during exercise revealed two components representing HbO2 and MbO2 deoxygenation. The data show that MbO2 represents approximately 40% of the NIRS signal and the balance or 60% to HbO2.

Online Assessment of Hemodynamics in the Suctioned Volume of Biological Tissue byan Embedded Near-Infrared Spectroscopy Sensor.

Cupping therapy is a promising method to cure or reduce symptoms of some diseases including muscle pain/tenderness/fatigue. Although the applications of cupping therapy have a thousand-year history in traditional Chinese medicine and have been spread to other countries in recent years, cupping therapy is something like a black box, and the unskilled user can hardly control it due to the absence of physiological observations. In this study, we developed a NIRS instrument with three probes to detect the blood-oxygen level of the skin tissue where the cupping therapy is being carried out. Each probe includes two detection channels. One of the probes is embedded in the cup to monitor the hemodynamic parameters in the cupping site, and the other two probes are placed outside, surrounding the cupping site. Using this monitor, we can observe the changes in oxy-hemoglobin ([HbO2]), deoxy-hemoglobin ([Hb]), and total hemoglobin ([tHb]), as well as the heart rate, calculated from the change curves of [HbO2] during cupping therapy in real time. Therefore, the doctor or other users can see the impact of cupping on the tissues to which it is applied which should facilitate the development and understanding of the application of cupping.

Abstract 372: Regional Cerebral Saturation in a Swine Model of Goal-directed Resuscitation of Prolonged Ventricular Fibrillation Cardiac Arrest

Introduction: The characteristics and limitations of near-infrared spectroscopy (NIRS) measurement of regional cerebral saturation (rSO2) for reflecting key moment-to-moment physiological changes needed to guide cardiopulmonary resuscitation (CPR) have yet to be fully determined. Objective: Examine the impact of NIRS sensor placement and resuscitation process variation on rSO2 measurements during prolonged cardiac arrest. Methods: Thirty mixed-breed domestic pigs (mean weight: 25.0kg+/-2.0) were sedated (ketamine / xylazine), anesthetized (fentanyl), paralyzed (vecuronium) and mechanically ventilated. Micromanometer pressure transducers were placed in the aorta and right atrium via femoral cutdown to measure central pressures, including mean arterial pressure (MAP) and coronary perfusion pressure (CPP). Two NIRS sensors were placed on the cranium: one on the skin surface and one on the bare skull. Ventricular fibrillation was induced electrically and untreated for 8 minutes followed by CPR. Initial BLS phase: 4 minutes of CPR at 100 compressions per minute (CPM) and 2 inches depth with manual ventilations (30:2). Randomized ALS phase: CPR with a pressor-titrated (Group A) or a compression rate/depth-titrated (Group B) strategy targeting 25mmHg CPP. Group A animals received pressor doses q1min and fixed rate/depth CPR. Group B animals received increasing rates and depth of CPR with epinephrine q3min. Defibrillation was attempted at 6min CPR q2min. rSO2 was compared between skin and skull across phases of resuscitation with t-tests and generalized estimating equations (GEE). Results: Mean skin and skull rSO2 differed marginally overall (63.8 vs 62.0, p &lt; 0.001), at baseline (69.9 vs 64.9, p &lt; 0.001), during BLS CPR (56.9 vs 48.7, p &lt; 0.001), during ALS CPR (59.5 vs 51.0, p &lt; 0.001), and following ROSC (70.0 vs 60.5, p&lt;0.001). rSO2 measured on either skull or skin both varied throughout phases of the experiment but not between CPR groups. In GEE models, rSO2 measured on skin or skull was not associated with MAP at baseline, but was directly associated during BLS (coef 0.13; p&lt;0.001) &amp; ALS CPR (coef 0.09; p&lt;0.001), and after ROSC (coef 0.02; p=0.017). Conclusion: rSO2 measures differ between skin and skull though both correlate with MAP.

Map-based variable-rate manure application in wheat using a data fusion approach

Poor manure management practices lead to excess nitrogen (N) and phosphorous (P) in soils that are still common in many countries in Europe. One way to optimize the economic returns and at the same time minimize the environmental impacts of poor manure management is by Variable Rate Manure (VRM) application. This work aimed at the evaluation of potential economic benefits of VRM application, compared to Uniform Rate Manure (URM) application, using advanced sensing, modeling and control technologies. Soil fertility attributes were measured using an on-line visible and near-infrared (vis-NIR) spectroscopy sensor, and crop normalized difference vegetation index (NDVI) was retrieved from Sentinel-2 images in a field of 8 ha with wheat in Flanders, Belgium. The predicted soil properties and the crop NDVI were clustered into a four-class fertility map using the k-mean clustering, each of which has different fertility level. The fertility map was overlaid by parallel strips representing URM, VRM1 and VRM2 treatments. VRM1 intended to apply 40 % more manure than URM to high fertility zones, 20 % more to medium-high fertility zones, 20 % less to medium-low fertility zones, and 40 % less to low fertility zones, whereas VRM2 adopted the opposite approach to that of VRM1. Results showed that VRM2 had increased crop yield by 1.5 % (0.19 t/ha), but reduced applied N by 4.1 % (11.01 kg/ha) and P by 7.1 % (3.72 kg/ha), compared to URM. The VRM1 approach consumed extra N of 5.21 kg/ha (1.8 %) and extra P of 1.63 kg/ha (3.1 %), to achieve a yield increase of 0.31 t/ha with a profit of 40.06 EUR/ha (2.1 %), compared to URM. However, a slightly smaller profit of VRM2 of 36.32 EUR/ha was calculated. Although VRM1 was more profitable than VRM2 by 0.2 % (3.74 EUR/ha), the latter is recommended as the best approach, as VRM1 increased environmental risks in the sense of increasing both N and P applied, by 5.9 % (17.12 kg/ha) and 10.4 % (5.35 kg/ha), respectively.

Tracing the Geographical Origins of Dendrobe (Dendrobium spp.) by Near-Infrared Spectroscopy Sensor Combined with Porphyrin and Chemometrics

Dendrobe (Dendrobium spp.) is a traditional medicinal and edible food, which is rich in nutrients and contains biologically active metabolites. The quality and price of dendrobe are related to its geographical origins, and high quality dendrobe is often imitated by low quality dendrobe in the market. In this work, near-infrared (NIR) spectroscopy sensor combined with porphyrin and chemometrics was used to distinguish 360 dendrobe samples from twelve different geographical origins. Partial least squares discriminant analysis (PLSDA) was used to study the sensing performance of traditional NIR and tera-(4-methoxyphenyl)-porphyrin (TMPP)-NIR on the identification of dendrobe origin. In the PLSDA model, the recognition rate of the training and prediction set of the TMPP-NIR could reach 100%, which was higher than the 91.85% and 91.34% of traditional NIR. And the accuracy, sensitivity, and specificity of the TMPP-NIR sensor are all 1.00. The mechanism of TMPP improving the specificity of NIR spectroscopy should be related to the π-π conjugated system and the methoxy groups of TMPP interact with the chemical components of dendrobe. This study reflected that NIR spectrum with TMPP sensor was an effective approach for identifying the geographic origin of dendrobe.