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Lean Body Mass Assessment Based on UV Absorbance in Spent Dialysate and Dual-Energy X-Ray Absorptiometry
摘要： Purpose: The aim of the study was to explore the possibility of assessing lean body mass (LBM) based on UV absorbance measurements in spent dialysate. Methods: 9 patients on chronic three-times-a-week HD (4 female, 5 male, mean age 58.8 ± 8.6 years) were studied. Blood and spent dialysate samples were collected for 3 consecutive hemodialysis (HD) sessions from every patient. A double-beam spectrophotometer was used for the determination of UV absorbance in the collected spent dialysate samples. Dual-energy x-ray absorptiometry (DXA) scans were performed on an interdialytic day. LBM was calculated based on creatinine concentration in blood (LBMblood) and UV absorbance in spent dialysate (LBMa) and assessed by DXA (LBMDXA). Also, in vitro experiments were carried out to investigate the effect of tissue hydration on DXA measurements. Results: Although LBMa was slightly lower compared to LBMblood, the estimates based on UV absorbance in spent dialysate presented greater accuracy and precision compared to LBMDXA. The significant difference between LBMblood and LBMDXA was with high probability caused by the altered tissue hydration of HD patents. Conclusions: In summary, the results show that it is possible to asses LBM based on UV absorbance in spent dialysate.
关键词： Lean body mass,Hemodialysis monitoring,Creatinine,Dual-energy x-ray absorptiometry,UV-absorption
更新于2025-09-23 15:22:29
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Automatic calibration of an arbitrarily-set near-infrared camera for patient surface respiratory monitoring
摘要： Purpose: A patient’s respiratory monitoring is one of the key techniques in radiotherapy for a moving target. Generally, such monitoring systems are permanently set to a fixed geometry during the installation. This study aims to enable a temporary setup of such a monitoring system by developing a fast method to automatically calibrate the geometrical position by a quick measurement of calibration markers. Methods: One calibration marker was placed on the isocenter and the other six markers were placed at positions 5-cm apart from the isocenter to the left, right, anterior, posterior, superior, and inferior directions. A near-infrared (NIR) camera (NIC) (Kinect v2 (Microsoft Corp.)) was arbitrarily set with ten different angles around the calibration phantom with a fixed tilting-down angle at approximately 45° in a linear accelerator treatment vault. The 3D coordinates in the camera (Cam) coordinate system (CS) (x and y are the horizontal and vertical coordinates of the image, respectively, and z is a coordinate along the NIR time-of-flight) were taken for one minute with 30 frames per second. The data corresponding to the measurement times of 1, 3, 10, 30, and 60 s were created to mimic various measurement times. These data were used to calculate the initial matrix elements, which included six parameters of the pitching, yawing, and rolling angles; horizontal 2D translation in the treatment room; and the source-to-axis distance of NIC, for a conversion from the Cam CS to the treatment-room CS for which the origin was defined at the isocenter (Iso coordinate). The six parameters were then optimized to minimize the displacements of the calculated marker coordinates from the actual positions in the Iso CS. The 3D positional accuracy and angular accuracy of the conversion were evaluated. The random error of the Iso coordinates was analyzed through a relation with the angle of each measurement setup. Results: Three angles of NIC and relative translation vectors were successfully calculated from the measurement data of the calibration markers. The achieved spatial and angular accuracies were 0.02 mm and 1.6°, respectively, after the optimization. Among the mimicked measurement times investigated in this study, both spatial and angular accuracies had no dependence on the measurement time. The average random error of a static marker was 0.46 mm after the optimization. Conclusion: We developed an automatic method to calibrate the 3D patient surface monitoring system. The procedure developed in this study enabled a quick calibration of NIC, which can be easily repeated multiple times for a frequent and quick setup of the monitoring system.
关键词： near-infrared camera,respiratory monitoring,calibration
更新于2025-09-23 15:22:29
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A Self-Reporting Photocatalyst for Online Fluorescence Monitoring of High Throughput RAFT Polymerization
摘要： Translating controlled/living radical polymerization (CLRP) from batch to the high throughput production of polymer libraries presents several challenges in terms of both polymer synthesis and characterization. Although recently there have been significant advances in the field of low volume, high throughput CLRP, techniques able to simultaneously monitor multiple polymerizations in an 'online' manner have not yet been developed. Here, we report our discovery that 5,10,15,20-tetraphenyl-21H,23H-porphine zinc (ZnTPP) is a self-reporting photocatalyst that can mediate PET-RAFT polymerization as well as report on monomer conversion via changes in its fluorescence properties. This enables the use of a microplate reader to conduct high throughput 'online' monitoring of PET-RAFT polymerizations performed directly in 384-well, low volume microtiter plates.
关键词： photochemistry,polymerization,online monitoring,PET-RAFT
更新于2025-09-23 15:22:29
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OPTically-based In situ Characterization System (OPTICS) to quantify concentrations and mass fluxes of mercury and methylmercury in South River, Virginia, USA
摘要： Historical releases of mercury to the South River (Virginia, USA) and mobilization of mercury from secondary sources (e.g., riverbed and riverbank sediments) is contributing to the redistribution of mercury to the water column. Therefore, in order to effectively remediate the South River, it is necessary to understand specific mechanisms for mercury contamination and transport in the system. An OPTically‐based In situ Characterization System (OPTICS) monitoring study was conducted to quantify concentrations and mass fluxes of mercury and methylmercury and to understand mechanisms of contaminant exchange between sediments and the water column. Storm flow and diel cycling (potentially related to nocturnal bioturbation activities) were identified as important mechanisms of particulate‐phase mercury and methylmercury exchange to the South River water column. It was determined that diel cycling contributed daily average mass transport of 0.01 kg of particulate mercury and 1.9E‐05 kg of particulate methylmercury, representing up to 13% and 16% of total mercury and methylmercury mass transported over the study period. Approximately 85% of the 3.6 and 0.01 kg total mass transport of particulate mercury and methylmercury over the study period was attributed to high storm flow, which likely resulted in resuspension of particle‐bound mercury and methylmercury and/or mobilization of fine‐grained channel margin deposits.
关键词： optical monitoring,mass fluxes,methylmercury,mercury,South River
更新于2025-09-23 15:22:29
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Multispectral imaging: Monitoring vulnerable people
摘要： This paper describes the development of a new healthcare monitoring system for vulnerable people which uses a visible image sensor and passive infrared sensors, in an unconventional manner, to monitor daily living activities. It based on a novel method, using chromatic methodology, to process spatially and temporally the incoming multispectral data from the visible and infrared parts of the spectrum, to overcome the impact of noisy environments, illumination changes and a dynamic background. An efficient chromatic descriptor is suggested to improve activity recognition of vulnerable people. The new monitoring system is robust to distortions associated with healthcare systems and its descriptor has an improved quality of description. System performance was evaluated using a series of experimental data, the results showing the efficacy of using both spatial and temporal domains of multispectral data to deal with events that disturb monitoring systems. The chromatic descriptor achieved a better performance in comparison to traditional methods when describing daily living activities.
关键词： Raspberry Pi,Laser image segmentation,Healthcare monitoring,Multispectral imaging,Microsoft Kinect
更新于2025-09-23 15:22:29
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Miniaturized pH Holographic Sensors for the Monitoring of Lactobacillus casei Shirota Growth in a Microfluidic Chip
摘要： Bioreactors have been used both to develop new, and to improve bioprocess yields for, biopharmaceutical products. However, efforts to miniaturize bioreactors, in order to save costs and accelerate process development times, have been limited by the lack of on-site monitoring capabilities available at such scales. In this study, small volume (3nL) non-consumptive holographic sensors were integrated into a glass-PDMS microfluidic chip to monitor via a blue-shift in the resultant holographic replay wavelength, the change in pH during microbial growth of Lactobacillus casei (L. casei) Shirota. Within the optimal growth pH range of L. casei, the accuracy of the miniaturized pH sensors was comparable to that of a conventional pH meter. Conceivably, this approach could be extrapolated to an array of miniaturized holographic sensors sensitive to different analytes, and thereby paving the way for reliable, real-time, non-invasive monitoring of microorganisms in a nanobioreactor.
关键词： microbioreactor,biosensor,pH monitoring,Holographic sensor,bacterial growth,microfluidic chip,nanobioreactor
更新于2025-09-23 15:22:29
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Strain Monitoring on PHC Pipe Piles Based on Fiber Bragg Grating Sensors
摘要： Fiber Bragg grating (FBG) sensors emerged as a relatively new strain-sensing technology for civil engineering applications. This study presents a field test to assess the feasibility of FBG sensors in monitoring the strain profile of prestressed high-strength concrete (PHC) pipe piles during installation. Two open-ended PHC pipe piles were instrumented with FBG sensors and then driven into the ground using a hydraulic jacking machine. To measure the strain profile along the test piles, nine FBG sensors were arranged in a single optical fiber and then mounted on one pile at the opposite side to monitor the strain at different levels as a function of wavelength shift. The procedure for installing the FBG sensors along the PHC pipe piles is introduced first. Next, the distribution of the axial forces and average side shear stresses that were evaluated from the strain measurements of the FBG sensors are discussed. The field test results indicate that the FBG sensor system was suitable for monitoring the strain state of PHC pipe piles during installation. The axial forces and side shear stresses along the test piles were influenced significantly by the penetration depth and the local soil resistance.
关键词： Fiber Bragg grating (FBG) technology,Jacking method,Strain monitoring,Prestressed high-strength concrete (PHC) pipe pile
更新于2025-09-23 15:22:29
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Impact paint sensor based on polymer/multi-dimension carbon nano isotopes composites
摘要： We presented a novel impact paint sensor made of piezoresistive nano-carbon composites and studied its characteristics. The paint sensors were fabricated with multi-walled carbon nanotube (MWCNT), exfoliated graphite nano-platelets (xGnP), and a hybrid type of the two nano-carbon fillers and were sprayed onto a carbon fiber reinforced plastic (CFRP) panel for lab testing. In ball drop impact test, the MWCNT-xGnP-based hybrid sensor showed the best characteristics in impact energy sensing within the range 0.07-1.0J. We also studied the piezoresistive mechanism due to dimensional variations of nano carbon isotopes for sensor design. Piezorestivity of nano-carbon sensor was significantly dominated the electrical contact variation of the electrical fillers in a matrix. This study is expected to provide a feasibility test for designing impact paint sensors with optimized sensitivity for a composite structural health monitoring (SHM).
关键词： Carbon nanotube (CNT),Exfoliated graphite nanoplate (xGnP),Structural health monitoring (SHM),Unmanned aerial vehicle (UAV),Impact paint sensor
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE SENSORS - New Delhi, India (2018.10.28-2018.10.31)] 2018 IEEE SENSORS - A CMUT - Based Electronic Nose for Real- Time Monitoring of Volatiles Emitted by Plants: Preliminary Results
摘要： Plants give off a unique profile of volatile organic compounds (VOCs) in response to abiotic and biotic stresses. The ability to discern specific VOC profiles provides for the early detection and subsequent treatment of insect infestation and pathogen infection. This work presents an electronic nose (e-nose) system based on a capacitive micromachined ultrasonic transducer (CMUT) with real-time monitoring capability for detecting and discriminating VOCs. Preliminary results show the almost instantaneous detection of the plant volatiles released systemically in response to physical wounding of plant tissue.
关键词： e-nose,real-time monitoring,plant stressors,volatile profile,gravimetric sensing,response fingerprint
更新于2025-09-23 15:22:29
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High sensitivity fiber optic sensor for hydrogen detection in gas and transformer oil
摘要： This paper reports on the characterisation of a palladium (Pd) based fiber optic hydrogen (H2) sensor for health monitoring of distribution and power transformers in the electrical grid. The sensor consists of a Pd foil, which expands due to H2 absorption, and a fiber Bragg grating (FBG) that measures this expansion. Fifteen sensors were manufactured and characterised in gas and oil environments at various H2 concentrations and temperatures. In gas, the sensors were evaluated at 60°C, 75°C, 90°C, 105°C and 120°C and H2 concentrations from 0.01 to 5%. In oil, the same sensors were evaluated at 90°C and dissolved H2 concentrations from 5 to 2700 ppm. Furthermore, the influence of carbon monoxide (CO), which is often present in transformers and can impact H2 response of the sensor, was investigated. At 90°C in gas, the response to 0.01%, and 5% H2 was on average 28 pm, and 719 pm respectively. At 90°C in oil, the response to 5 ppm, and 2700 ppm dissolved H2 was on average 11 pm, and 763 pm respectively. The average, relative accuracy is better than 20% over the whole measurement range in gas and for measurements above 100 ppm in oil. These specifications make the sensor a promising candidate for online monitoring of H2 in transformers.
关键词： transformer monitoring,Hydrogen,fiber Bragg grating,palladium,gas detection
更新于2025-09-23 15:22:29