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Portable Mid-Infrared Device and Chemometrics for the Prediction of Low (0.5%) Total <i>Trans</i> Fat Content in Fast Foods
摘要： The ruling that partially hydrogenated oils (PHO) are no longer “generally recognized as safe (GRAS),” has accelerated the replacement of PHO ingredients with fat alternatives having increasingly lower or no trans fat content. In the present study, we developed a Fourier-transform infrared (FTIR) spectroscopic procedure in conjunction with multivariate partial least squares regression (PLSR) and found it suitable for the accurate prediction of low (0.5%) total trans fat content, as percentage of total fat, measured as fatty acid methyl esters (FAME), in the lipids extracted from 24 representative fast foods. This multivariate data analysis approach is relevant because the precision of the current univariate FTIR official method (AOCS Cd 14-09) is reportedly poor below 2% of total fat, while PLSR has allowed us to accurately predict the concentration of low trans fat in fast foods. The performance of a portable FTIR device was also evaluated and compared to that of a benchtop FTIR spectrometer. For both infrared data sets, PLSR-predicted concentrations of total trans FAME, ranging from approximately 0.47% to 11.40% of total FAME, were in good agreement with those determined by a primary reference gas chromatography (GC) method (R2>0.99); high prediction accuracy was also evidenced by low root mean square error of cross-validation (RMSECV) values. The lowest RMSECV error of 0.12% was obtained with the portable device. The lowest total trans FAME concentration, determined by GC to be 0.42%, was accurately predicted by the portable FTIR/PLSR procedure as 0.47% of total FAME.
关键词： partial least squares regression,portable device,infrared spectroscopy,low trans fat content,fast foods
更新于2025-09-09 09:28:46
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A First Response Microcontroller Based Digital Radiation Survey Meter Using Scintillation Detector
摘要： This paper presents the microcontroller based advanced technique to design and development of a portable radiation survey meter to measure low level gamma radiation using NAI(T1) scintillation detector. A scintillation detector was used as radiation detector and a microcontroller PIC16F876 was used to control the function of the developed system. The microcontroller generated square wave frequency at specified pulse width to produce high voltage (+1200V) and regulates it. The high voltage was required to activate the scintillation detector. Preamplifier and amplifier were designed to make the detector signal for the further amplification. Microcontroller senses the pulses from the amplifier output and processes data by software and displays the results. The microcontroller was programmed using a high level programming language ‘C’ with PCWH compiler.
关键词： PIC16F876,Digital and Portable,Scintillation detector,PCWH,NaI (T1),Gamma ray
更新于2025-09-09 09:28:46
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Radioguided Parathyroidectomy with Portable Mini Gamma-Camera for the Treatment of Primary Hyperparathyroidism
摘要： Background. A proper localisation of pathological parathyroid glands is essential for a minimally invasive approach in the surgical treatment of primary hyperparathyroidism (PHP). The recent introduction of portable mini gamma-cameras (pMGCs) enabled intraoperative scintigraphic scanning. The aim of our study is to evaluate the efficacy of this new method and compare it with the preoperative localisation surveys. Methods. 20 patients were studied; they were evaluated preoperatively by neck ultrasound and 99mmTc-sestaMIBI-scintigraphy and intraoperatively with the pMGC IP Guardian 2. The results obtained from the three evaluations were compared. Results. The pMGC presented a sensitivity of 95%, a specificity of 98.89%, and a diagnostic accuracy of 98.18%, which were higher than those of preoperative ultrasound (sensitivity 55%; specificity 95%; diagnostic accuracy 87%) and scintigraphy with 99mmTc-sestaMIBI (sensitivity 73.68%; specificity 96.05%; diagnostic accuracy 91.58%). Conclusions. The pMGC can be used effectively as an intraoperative method to find the correct location of the pathological parathyroid glands. The pMGC is more reliable than the currently used preoperative and intraoperative localisation techniques.
关键词： portable mini gamma-camera,intraoperative scintigraphic scanning,localisation techniques,primary hyperparathyroidism,parathyroidectomy
更新于2025-09-09 09:28:46
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Development of a micro-joule portable LIBS system and the preliminary results for mineral recognition
摘要： Laser-induced breakdown spectroscopy (LIBS) has been extensively applied due to the capabilities of real-time, multi-phase and multi-element analysis. With the advantages, portable LIBS is in rapid development with great potential of field measurements. In this work, a portable LIBS was developed by a 50 μJ level laser for excitation and an objective lens for focusing or imaging. Element detection was successfully achieved by this setup, and also the microscopic observation could be obtained with the magnification of 350×. A preliminary investigation was carried out for mineral recognition by the developed portable LIBS. The obtained results indicate that the element detection combined with micro observation was an effective way for recognizing minerals, especially for similar mineral identification or discrimination. It is suggested that the micro-joule laser could be alternative for the commercial portable LIBS, and the on-site mineral or rock recognition is a promising field for the application.
关键词： LIBS,micro-joule laser,micro observation,mineral recognition,portable
更新于2025-09-04 15:30:14
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[ACS Symposium Series] Raman Spectroscopy in the Undergraduate Curriculum Volume 1305 || Analysis of Over-the-Counter Drugs Using Raman Spectroscopy
摘要： Commercial over-the-counter drugs such as Advil?, Aleve?, Tylenol?, Mucinex?, Excedrin?, and aspirin were analyzed with a portable handheld Raman spectrometer. The peaks from their Raman spectra were determined, and common peaks were observed in all samples. Unique peaks were also noticed and used as identifying markers to identify a particular drug. Theoretical calculations of active ingredients present in drugs were also performed, compared with experimental Raman spectra, and used to assign the functional groups responsible for the peaks. In addition, Raman spectra obtained from a benchtop instrument were also compared with that from a portable Raman spectrometer. Different forms and brands of the drugs were also analyzed to determine the effect of other materials on the active ingredient. Results showed that the dosage of active ingredients has a direct impact on the signals exhibited in Raman spectra. Lastly, different degradation processes (exposure to microwaves, UV light, and high temperature) were tested on Tylenol? and results showed peak changes in certain regions and more fluorescence background.
关键词： active ingredients,Raman spectroscopy,over-the-counter drugs,degradation processes,portable handheld Raman spectrometer
更新于2025-09-04 15:30:14
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Impact of heterogeneities and surface roughness on pXRF, pIR, XRD and Raman analyses: Challenges for on-line, real-time combined mineralogical and chemical analyses on drill cores and implication for “high speed” Ni-laterite exploration
摘要： On-line, real-time chemical and mineralogical analyses on drill cores are highly demanded by mining companies. However, they are a challenge because of drill core surface state and sample heterogeneities. We selected four rock samples: highly porous, siliceous breccia and serpentinized harzburgite coming from the base of a nickel laterite profile in New Caledonia which were sonic drilled, and fine grained, homogeneous sandstone and coarse grained granite which were diamond drilled and provided by Eijkelkamp Sonic Drill with unknown origin. The samples were analyzed at five surface states (diamond or sonic drilled, cut as squares, polished at 6 and 0.25 microns, powdered < 80 microns) by portable XRF spectroscopy (pXRF) in mining and soil modes and portable infrared spectroscopy (pIR, Visible and Near Infrared - Short Wave Infrared range (VNIR-SWIR)). A total of 52 pXRF and 200 pIR analyses were performed per sample at each surface state. This study shows that the surface state has minor influence on the results of the portable instruments. By comparing pIR and pXRF results with laboratory devices (Raman spectroscopy, XRD with Rietveld refinement, XRF spectroscopy and ICP-AES), we evidence the lower and less accurate information obtained from handheld instruments in terms of chemistry and mineralogy. The porosity and grain size effect on the measurement need to be taken into consideration for on-line drill core analyses. We show that the combination of complementary analytical techniques helps to overcome the drawbacks of the core texture and of the precision of portable instruments in order to define the regions of interest (ROI) for mining companies. We also demonstrate that a precise pXRF calibration is mandatory and that the concentration of light elements (Si, Mg), even if not accurate, shows sufficient contrast along the lateritic profile for ROI definition.
关键词： drill cores,nickel,portable instruments,surface effects,garnierite
更新于2025-09-04 15:30:14
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[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - Evaluation of Positioning Techniques for Millimeter-wave Portable Scanners
摘要： Hybrid methods that combine electromagnetic and optical three dimensional (3D) imaging can be used to scan objects or bodies at millimeter-wave frequencies by merging multiview information. The first goal of the optical model is to obtain a 3D representation of the external surface of the target under test. The second goal lies in the estimation of positions and attitude angles of the electromagnetic scanner in order to properly combine the data collected at each acquisition view. In this contribution, two different positioning techniques are evaluated. The first one is based on a conventional optical camera, whereas the second one relies on a depth camera. Finally, an example of application to security screening is used to evaluate the accuracy of both methods.
关键词： millimeter-wave imaging,RGB-D,photogrammetry,portable scanner,depth camera,structured light
更新于2025-09-04 15:30:14
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High-resolution cost-effective compact portable inverted light microscope
摘要： Commercial high-resolution optical microscopes are essential for microscopy imaging; however, they are expensive and bulky, which limits their use in point-of-care devices, resource-limited areas, and real-time imaging of a sample in a large apparatus. In this study, we report a novel compact (10 cm × 5 cm × 5 cm, without the light source) lightweight (≤0.5 kg) submicron-resolution inverted optical microscope at low cost (≤$ 300). Our technique utilises the proximity of the image sensor to a commercial microscope objective lens for compactness of the microscope. The use of an image sensor with a small pixel size helps to reduce the information loss, which provides high-resolution images. Moreover, our technique offers a freedom to tailor the design of microscope according to the required resolution, cost, and portability for specific applications, which makes it a suitable candidate for affordable point-of-care devices. Images of several micron-to-submicron scale patterns and spherical beads are acquired to observe the resolution and quality of the images obtained using our microscope. In addition, we demonstrate the applications of our microscope in various fields such as recording of high-speed water micro-droplet formation inside a microfluidic device, high-resolution live cell imaging inside an incubator, and real-time imaging of crack propagation in a sample under stretching by a material testing system (MTS). Therefore, this portable and inexpensive microscope provides the essential functionalities of a bulky expensive high-performance microscope at a lower cost.
关键词： portable inverted microscope,microfluidics,discrete wavelet transform,submicron-scale imaging,industrial microscope,Cell imaging
更新于2025-09-04 15:30:14
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Accuracy of a Smartphone-based Autorefractor Compared with Criterion-standard Refraction
摘要： SIGNIFICANCE: Uncorrected refractive error is a prevalent problem throughout the world especially among the low-income population who have limited access to professional eye care and cannot afford eyeglasses. PURPOSE: The purpose of this study was to evaluate the accuracy and usability of a low-cost, portable, smartphone-based autorefractor (Netra, EyeNetra Inc., Somerville, MA) in adults. METHODS: A cross-sectional study was conducted to compare the portable refractor with subjective (manifest and cycloplegic) refraction for sequential adult participants with best-corrected visual acuity of 20/40 or greater. For each method of refraction, the spherical equivalent was calculated. Differences between methods were tested with linear mixed regression models. A validated usability questionnaire was administered regarding ease of use (100-point scale, higher scores better) for the portable autorefractor. RESULTS: Eighty-seven subjects (152 eyes) were studied (age range, 20 to 90 years; mean ± standard deviation, 51.9 ± 18.3 years). Mean spherical equivalent by the portable device was ?2.76 D (range, ?14.75 to 3.63 D) compared with ?2.49 D (range, ?15.25 to 4.25 D) by manifest refraction. The mean relative difference in spherical equivalent between methods was ?0.27 D (P = .001, significantly different than 0 D). The mean absolute difference between methods was 0.69 D (P < .001, significantly different than 0.5-D absolute difference). Similar results were found when comparing spherical equivalent between Netra and cycloplegic refraction methods. Subjects reported average ease of use for the Netra of 75.4 ± 19.8. CONCLUSIONS: The portable autorefractor had small but clinically significant differences from subjective refraction. The device's scores on the usability scale indicate good overall patient acceptance. The device may be valuable for use where there is limited access to a trained refractionist.
关键词： autorefractor,portable,smartphone-based,low-cost,refractive error
更新于2025-09-04 15:30:14