Near-infrared Measurements Research Articles

On-Site Identification of the Material Composition of PV Modules with Mobile Spectroscopic Devices

With the increased development of portable and handheld molecular spectrometers within recent years, new fields of applications have opened up, such as their use (i) for material identification of samples contained in large and non-portable components and (ii) the detection of material degradation effects and failures directly in the plant. The usability and transferability of well-established analytical characterization techniques, such as attenuated total reflection (ATR) Infrared (IR)-, Raman, and Near-Infrared (NIR)-spectroscopy as mobile devices for the in-field characterization of Photovoltaic (PV) modules, are described and discussed. Material identification of the polymeric compounds incorporated in the PV modules (encapsulants, backsheets) is often an important task, especially when degradation and failures occur. Whereas the knowledge of the bill of materials is one challenge, the detection of material degradation effects is another important issue. Both tasks can be solved nondestructively by the application of mobile spectrometers. Raman spectroscopy is the best-suited method for the identification of the encapsulant within the module (measurement through 3-mm glass), while NIR measurements allowed for the nondestructive determination of the composition of the multilayer backsheet. Surface degradation effects (e.g., oxidation, hydrolysis) are best detectable with IR-spectroscopy. The application of mobile devices allows for direct material analysis in the field without dismantling PV modules, transporting them to the lab, cutting them in smaller pieces, and analyzing them in conventional bench-top spectrometers.

The near and mid-infrared photometric properties of known redshift z ≥ 5 quasars

ABSTRACT We assemble a catalogue of 488 spectroscopically confirmed very high (z ≥ 5.00) redshift quasars (VHzQ) and report their near- (ZYJHKs/K) and mid- (WISE W1234) infrared properties. 97 per cent of the VHzQ sample is detected in one or more near-infrared (NIR) band, with lack of coverage rather than lack of depth being the reason for the non-detections. 389 (80 per cent) of the very high redshift quasars are detected at 3.4 μm in the W1 band from the unWISE catalogue and all of the z ≥ 7 quasars are detected in both unWISE W1 and W2. Using archival Wide Field Camera (WFCAM)/United Kingdom Infrared Telescope (UKIRT) and VISTA Infrared Camera (VIRCAM)/Visible and Infrared Survey Telescope for Astronomy (VISTA) data we check for photometric variability that might be expected from super-Eddington accretion. We find 28 of the quasars have sufficient NIR measurements and signal-to-noise ratio to look for variability. Weak variability was detected in multiple bands of Sloan Digital Sky Survey (SDSS) J0959+0227, and very marginally in the Y-band of MMT J0215-0529. Only one quasar, SDSS J0349+0034, shows significant differences between WFCAM and VISTA magnitudes in one band. With supermassive black hole accretion likely to be redshift invariant up to very high redshift, further monitoring of these sources is warranted. All the data, analysis codes and plots used and generated here can be found at: github.com/d80b2t/VHzQ.

Nd3+ CONCENTRATION DEPENDENT OPTICAL FEATURES OF GADOLINIUM BOROPHOSPHO-TELLURITE GLASSES

Improving the optical response of glass host with two or more strong network formers via suitable controlled of rare earth ions is the key issue in the fabrication of optical based glass for solid state lasers and light emitting devices. Hence, we report the Nd3+ concentration dependent on optical parameters such as absorption edge, optical band gap (direct and indirect) and Urbach’s energy of gadolinium borophospho-tellurite glasses with chemical composition of 10Gd2O + 30B2O3 + 20P2O5 + (40-)TeO2 + Nd2O3 (where 0.0 ≤ x ≤ 1.0 mol%). The glass samples were synthesized by convectional melt quenching method and characterized through X-Ray Diffraction (XRD) and Ultraviolet Visible Near-Infrared (UV-Vis-NIR) measurements. The amorphous nature of these glasses was confirmed by X-Ray diffraction pattern while the UV-Vis-NIR spectra revealed six absorption peaks corresponding to the transition from ground level 4I9/2 to the various excited state of Nd3+ ions. It was found that the investigated range of Nd3+ doping concentrations has a great influence on aforementioned parameters. The excellent optical features established in the present glass host suggest their potentiality for solid-state lasers and other photonic applications.
 Bulus, I. | Department of Physics, School of Sciences, Kaduna State College of Education Gidan waya, Kafanchan, Nigeria

Potential of Vis-NIR spectroscopy for detection of chilling injury in kiwifruit

Abstract This study examined the non-destructive assessment of chilling injury in Actinidia chinensis var. chinensis ‘Zesy002’ kiwifruit by means of visible – near infrared interactance spectroscopy. Chilling injury is a physiological disorder which may develop when kiwifruit are stored at commercial storage temperature of 0−1 °C. Symptoms may include a granular appearance, corky outer pericarp and water-soaked tissue. The initial symptoms are visible only when the fruit is cut open. The data set used in this study consisted of 129 ‘Zesy002’ kiwifruit, with chilling injury symptoms assessed visually when the fruit was dissected and classified on a five-point severity scale from sound to severe. Near-infrared (NIR) interactance spectral analysis (principal component analysis with standard normal variate (SNV) pre-processing on the wavelength range of 700–1000 nm) was effective in segregating the fruit by symptom severity. A stronger separation between severely damaged fruit and sound fruit was achieved when the NIR measurements were made at the stylar end of the fruit. The optical properties of absorption and scattering coefficients were measured on a selection of excised kiwifruit slices and extracted kiwifruit juice using inverse adding-doubling and light transmittance methods, respectively. A comparative examination of impact damaged fruit (data set of 22 fruit; 11 sound, 11 impacted) gave an alternative perspective on water-soaked tissue, which has a similar appearance in chilling injured and impact damaged fruit, but showed different spectral shapes. It is speculated that the presence of water-soaked tissue might be less informative after SNV processing than corky and granular tissue for the detection of chilling injury. This study reports that there is good potential to use NIR spectroscopy for detecting kiwifruit with chilling injury symptoms.

The resolved size and structure of hot dust in the immediate vicinity of AGN

We use VLTI/GRAVITY near-infrared interferometry measurements of eight bright type 1 AGN to study the size and structure of hot dust that is heated by the central engine. We partially resolve each source, and report Gaussian full width at half-maximum sizes in the range 0.3−0.8 mas. In all but one object, we find no evidence for significant elongation or asymmetry (closure phases ≲1°). The narrow range of measured angular sizes is expected given the similar optical flux of our targets, and implies an increasing effective physical radius with bolometric luminosity, as found from previous reverberation and interferometry measurements. The measured sizes for Seyfert galaxies are systematically larger than for the two quasars in our sample when measured relative to the previously reported R ∼ L1/2 relationship, which is explained by emission at the sublimation radius. This could be evidence of an evolving near-infrared emission region structure as a function of central luminosity.

Developing and Implementing an R Shiny Application to Introduce Multivariate Calibration to Advanced Undergraduate Students

During a short chemometrics course in the seventh semester of the chemistry undergraduate program, students receive a brief theoretical introduction to multivariate calibration, focused on partial least-squares regression as the most commonly employed data processing tool. The theory is complemented with the use of MVC1_R, an easy-to-use software developed in-house as an R Shiny application. The present report describes student activities with the latter software in the development of mathematical models to predict quality parameters of corn seeds from near-infrared spectra. Subsequently, an experimental project is carried out involving near-infrared spectral measurements, which are widely used in several industrial fields for quality control. To process the obtained data, students apply the knowledge acquired during the theoretical/software sessions.

A spatially resolved transmittance spectroscopy system for detecting internal rots in onions

Abstract This study presents the development of a spatially resolved transmittance system for detecting internal rots in onions, particularly small and localised rots. A two-wavelength classifier was chosen by considering sensitivities to rots and path-length variations. Near-infrared spectroscopy transmittance measurements were carried out on rot-affected onions, to determine wavelength sensitivities to the presence and severity of rots. Finite Element simulations of light transport in onions were run to determine wavelength sensitivities to source-detector separation. A spatially resolved transmittance system was then developed, using two laser diodes as sources (728 and 805 nm wavelengths) and a single photodiode as detector. The system was experimentally verified, with the measured spatial profiles of the transmittance ratios of the two source wavelengths being sensitive to variation in position and size of internal rots in onions.

The Effect of Light Intensity, Sensor Height, and Spectral Pre-Processing Methods when using NIR Spectroscopy to Identify Different Allergen-Containing Powdered Foods.

Food allergens present a significant health risk to the human population, so their presence must be monitored and controlled within food production environments. This is especially important for powdered food, which can contain nearly all known food allergens. Manufacturing is experiencing the fourth industrial revolution (Industry 4.0), which is the use of digital technologies, such as sensors, Internet of Things (IoT), artificial intelligence, and cloud computing, to improve the productivity, efficiency, and safety of manufacturing processes. This work studied the potential of small low-cost sensors and machine learning to identify different powdered foods which naturally contain allergens. The research utilised a near-infrared (NIR) sensor and measurements were performed on over 50 different powdered food materials. This work focussed on several measurement and data processing parameters, which must be determined when using these sensors. These included sensor light intensity, height between sensor and food sample, and the most suitable spectra pre-processing method. It was found that the K-nearest neighbour and linear discriminant analysis machine learning methods had the highest classification prediction accuracy for identifying samples containing allergens of all methods studied. The height between the sensor and the sample had a greater effect than the sensor light intensity and the classification models performed much better when the sensor was positioned closer to the sample with the highest light intensity. The spectra pre-processing methods, which had the largest positive impact on the classification prediction accuracy, were the standard normal variate (SNV) and multiplicative scattering correction (MSC) methods. It was found that with the optimal combination of sensor height, light intensity, and spectra pre-processing, a classification prediction accuracy of 100% could be achieved, making the technique suitable for use within production environments.

A robust visible near-infrared index for fire severity mapping in Arctic tundra ecosystems

Tundra fires are projected to increase with anthropogenic climate change, yet our ability to assess key wildfire metrics such as fire severity remains limited. The Normalized Burn Ratio (NBR) is the most commonly applied index for fire severity mapping. However, the computation of NBR depends on short-wave infrared (SWIR) data, which are not commonly available from historical and contemporary high-resolution (≤4 m) optical imagery. The increasing availability of visible near-infrared (VNIR) measurements from proximal to spaceborne sensors/platforms has the potential to advance our understanding of the spatiotemporal patterns of fire severity within tundra fires. Here we systematically assess the feasibility of using VNIR data for fire severity mapping in ten Alaskan tundra fires (cumulatively burned ~1700 km2). We compared the accuracy of 10 published VNIR-based fire indices using both uni-temporal (post-fire image) and bi-temporal (pre-fire and post-fire image difference) assessments against ground-based fire severity data (Composite Burn Index, CBI) at 109 tundra sites. The Global Environmental Monitoring Index (GEMI) had the highest correspondence with CBI (R2 = 0.77 uni-temporal; R2 = 0.85 bi-temporal), with similar performance to NBR (R2 = 0.77 uni-temporal; R2 = 0.83 bi-temporal). Tundra vegetation types affected NBR but not GEMI, as SWIR reflectance was influenced to a greater extent in shrub than graminoid tundra. We applied GEMI to contemporary high-resolution (i.e. Quickbird 2) and historical meso-resolution imagery (i.e. Landsat Multispectral Scanner) to demonstrate the capability of GEMI for resolving fine-scale patterns of fire severity and extending fire severity archives. Results suggest that GEMI accurately captured the heterogeneous patterns of tundra fire severity across fire seasons, ecoregions, and vegetation types.

Potential of Near-Infrared Spectroscopy to Evaluate the Cleaning Performance of Dishwashing Processes

Abstract Automatic dishwashing is a process which takes enormous amounts of resources (energy, water, chemicals). However, most of the dishwashing programs are designed and tested to clean the worst scenario for a certain kind of load items (glass, porcelain, etc.) and do not or only partly adapt to the actual load and soiling conditions. Thus, resources are wasted which could be avoided if a better adaptation to the actual status of the dishwashing process would be possible. It is, therefore, the aim of this study to investigate the possibility of using near-infrared technology to evaluate the status of the dishwashing process by analyzing the content of soil components already dissolved in the dishwashing water. Compared to other methods, the main advantage of near-infrared measurements is the possibility to differentiate between soils or soil components (carbohydrates, fats and protein) at very low concentrations. Near-infrared spectroscopy implemented in an automatic dishwasher could observe and evaluate an automatic dishwashing processes by using online measurements of the detachment of soils from soiled dishes. Thirty-seven model emulsions containing detergent, tap water, different soils and soil concentrations were created and measured by using near-infrared spectroscopy to demonstrate its suitability for the evaluation of dishwashing processes. The spectra were the basis of developing near-infrared calibration models for each soil component using the partial least squares regression method with internal cross-validation. The coefficients of determination in internal cross-validation (R²) are 0.88 for carbohydrates, 0.92 for fats and 0.99 for proteins. Thereafter, the calibration models developed were externally validated with samples of known concentrations of these soil components. The known concentrations were determined during external validation. The results of calibration and evaluation show that it is generally possible to measure very low concentrations of soil components in dishwashing liquor. The applicability to a real dishwashing process and the usage of other soils has yet to be tested.

P3588The synergistic effect of NIRS-detected lipid-rich plaque and 5 different multidirectional wall shear stress metrics on human coronary plaque growth

Abstract Introduction Local wall shear stress (WSS) metrics, high local lipid levels (as detected by near-infrared spectroscopy (NIRS)), as well as systemic lipid levels, have been individually associated with atherosclerotic disease progression. However, a possible synergistic effect remains to be elucidated. This study is the first study to combine WSS metrics with NIRS-detected local lipid content to investigate a potential synergistic effect on plaque progression in human coronary arteries. Methods The IMPACT study is a prospective, single centre study investigating the relation between atherosclerotic plaque progression and WSS in human coronary arteries. Patients with ACS treated with PCI were included. At baseline and after 1-year follow-up, patients underwent near-infrared spectroscopy intravascular ultrasound (NIRS-IVUS) imaging and intravascular doppler flow measurements of at least one non-culprit coronary artery. After one month, a CT angiography was made. CT derived centreline combined with IVUS lumen contours resulted in a 3D reconstruction of the vessel. The following WSS metrics were computed using computational fluid dynamics applying the vessel specific invasive flow measurements: time-average wall shear stress (TAWSS), relative residence time (RRT), cross-flow index, oscillatory shear index and transverse wall shear stress. Low TAWSS is known as pro atherogenic, in contrast to all the other shear stress metrics, at which a high magnitude is pro-atherogenic. The arteries were divided into 1.5mm/45° sectors. Based on NIRS-IVUS, wall thickness change over time was determined and NIRS positive sectors detected. Furthermore, per vessel the shear stress was divided into tertiles (low, intermediate, high). To investigate the synergistic effect of local lipids on shear stress related plaque growth, wall thickness change over time was related to the different shear stress metrics comparing the NIRS-positive with the NIRS-negative sectors. Results 15 non-culprit coronary arteries from the first 14 patients were analyzed (age 62±10 years old and 92.9% male). A total of 2219 sectors were studied (5.2%, N=130, NIRS-positive) for wall thickness changes. After studying all five shear stress metrics, we found for TAWSS and RRT that presence of lipids, as detected by NIRS, amplified the effect of shear stress on plaque progression (see figure). Sectors presenting with lipid-rich plaque, compared to NIRS-negative sectors, showed more progression when they were exposed to low TAWSS (p=0.07) or high RRT (p=0.012) and more regression in sectors exposed to high TAWSS (p=0.10) or low RRT (p=0.06). Delta wall thickness vs shear stress Conclusion We presented the first preliminary results of the IMPACT study, showing the synergistic effect of lipid rich plaque and shear stress on plaque progression. Therefore, intravascular lipid-rich plaque (NIRS) assessment has added value to shear stress profiling for the prediction of plaque growth, leading to improved risk stratification. Acknowledgement/Funding ERC starting grant 310457

Fluorescence features of Tm3+-doped multicomponent borosilicate and borotellurite glasses for blue laser and S-band optical amplifier applications

Novel B2O3–SiO2–Al2O3–ZnO–Li2O/MgO and B2O3–TeO2–PbO–ZnO–Li2O–Na2O glasses with different concentrations of Tm2O3 were synthesized by using the melt-quench method. All the fabricated samples have been characterized by visible emission spectra and decay times, including near-infrared (NIR) luminescence measurements. For 0.5 mol% Tm3+-doped borotellurite glass, several radiative parameters are evaluated using the Judd-Ofelt parameters. The intensity of all the visible emission bands increased with the increase of Tm2O3 concentration up to 0.5 mol%, and beyond this doping content, luminescence concentration quenching takes place. The luminescence intensity quenching is attributed to energy transfer (ET) processes through cross-relaxation (CR) channels. The visible luminescence decay curves were well fit with a single exponential (for Tm3+: 1D2 level) and double exponential (for Tm3+: 1G4 level) functions for the multicomponent borosilicate samples, while Inokuti-Hirayama model was used for the multicomponent borotellurite glass 1D2 level decay time fit. The derived decay lifetimes of the 1D2 level are found to be much shorter than that of the 1G4 level. In Li2O (alkali) or MgO (alkaline) containing borosilicate samples, pumped under 808 nm laser diode, the 3H4→3F4 (1.458 μm) emission intensity increased from 0.1 to 2.0 mol% Tm3+ ion concentration, indicating negligible CR processes. The computed Full-Width at Half-Maximum (FWHM) values for the 1458 nm emission in 2.0 mol% Tm3+-doped Li and Mg series borosilicate samples are 117 and 125 nm, respectively, while the FWHM value for 0.5 mol% Tm2O3 content doped borotellurite glass is 118 nm. Following the analyzed visible and NIR optical results, the fabricated Tm3+ glasses could be useful for blue laser and S-band optical amplifier applications.

Glasgow Coma Scale Score Fluctuations are Inversely Associated With a NIRS-based Index of Cerebral Autoregulation in Acutely Comatose Patients.

The Glasgow Coma Scale (GCS) is an essential coma scale in critical care for determining the neurological status of patients and for estimating their long-term prognosis. Similarly, cerebral autoregulation (CA) monitoring has shown to be an accurate technique for predicting clinical outcomes. However, little is known about the relationship between CA measurements and GCS scores among neurological critically ill patients. This study aimed to explore the association between noninvasive CA multimodal monitoring measurements and GCS scores. Acutely comatose patients with a variety of neurological injuries admitted to a neurocritical care unit were monitored using near-infrared spectroscopy-based multimodal monitoring for up to 72 hours. Regional cerebral oxygen saturation (rScO2), cerebral oximetry index (COx), GCS, and GCS motor data were measured hourly. COx was calculated as a Pearson correlation coefficient between low-frequency changes in rScO2 and mean arterial pressure. Mixed random effects models with random intercept was used to determine the relationship between hourly near-infrared spectroscopy-based measurements and GCS or GCS motor scores. A total of 871 observations (h) were analyzed from 57 patients with a variety of neurological conditions. Mean age was 58.7±14.2 years and the male to female ratio was 1:1.3. After adjusting for hemoglobin and partial pressure of carbon dioxide in arterial blood, COx was inversely associated with GCS (β=-1.12, 95% confidence interval [CI], -1.94 to -0.31, P=0.007) and GCS motor score (β=-1.06, 95% CI, -2.10 to -0.04, P=0.04). In contrast rScO2 was not associated with GCS (β=-0.002, 95% CI, -0.01 to 0.01, P=0.76) or GCS motor score (β=-0.001, 95% CI, -0.01 to 0.01, P=0.84). This study showed that fluctuations in GCS scores are inversely associated with fluctuations in COx; as COx increases (impaired autoregulation), more severe neurological impairment is observed. However, the difference in COx between high and low GCS is small and warrants further studies investigating this association. CA multimodal monitoring with COx may have the potential to be used as a surrogate of neurological status when the neurological examination is not reliable (ie, sedation and paralytic drug administration).

Pharmaceutical formulation analysis of a gelatin-based soft capsule film sheet containing phytic acid using near-infrared spectroscopy

In order to investigate the effect of phytic acid on the improvement of disintegration time (DT) of gelatin-based film sheets, gelatin film sheets and succinylated gelatin film sheets with various concentrations of phytic acid were dipped and stored in polyethylene glycol (PEG) 400 at 60 °C. The DT and near infrared (NIR) spectral changes were measured after storage. Gelatin showed a tendency to prolong DT caused by the formation of insoluble thin membranes due to the cross-linking of gelatin molecules, whereas succinylated gelatin did not show prolongation of DT. We also observed the preventive effect of phytic acid on the prolongation of DT of gelatin film sheets as the phytic acid concentration increased. From NIR measurements, it was considered that the –OH groups of phytic acid were coordinated with the hydrogen bonding position of gelatin molecules by replacing H2O or glycerin molecules. It was also thought that structural changes in the gelatin-water-glycerin complexes caused by phytic acid interfered with the access of peroxide or aldehyde generated from PEG 400 to the free ε–NH2 groups and prevented the cross-linking of gelatin molecules. On the other hand, because the free ε-NH2 groups of succinylated gelatin are protected by acid amidation, the cross-linking of succinylated gelatin was not observed.

Compressed sensing method for measuring absorption spectrum of liquid samples

For low-light or near-infrared absorption spectrum measurements, it is challenging to obtain high resolution spectra due to limitations of exotic array detectors. In this paper, a new spectral measurement method based on compressed sensing (CS) is reported. An experimental spectrometer is constructed and calibrated, and the absorption spectra of two liquid samples are measured. Along with a high resolution, the new method has a better signal-to-noise ratio (SNR) than the conventional scanning spectroscopy technique. The measurement resolution of our experimental system is 0.38 nm. The result of wavelength position calibration is accurate. The peak value of characteristic spectrum of red sample is 730 nm, and that of blue sample are 440 nm and 740 nm.

Freshness Evaluation in Chub Mackerel (Scomber japonicus) Using Near-Infrared Spectroscopy Determination of the Cadaverine Content

We analyzed the volatile basic nitrogen content, pH, total viable cell count, and biogenic amine contents in chub mackerel (Scomber japonicus) stored at 5 and 25°C to examine changes in freshness. Among the various parameters, we found the volatile basic nitrogen content had the highest correlation with cadaverine content (r2 = 0.72 to 0.88). We also tried to measure cadaverine contents at different times during storage by using near-infrared (NIR) spectroscopy. However, because of the high water content in the fish, we could not obtain meaningful results. Next, we prepared samples for NIR spectroscopy by dilution with 0.1 N HCl, ultrafiltration (3 or 10 kDa) with a glass filter, and dehydration. The samples prepared with the 3-kDa filter had peaks in the NIR spectra between 1,379.3 and 1,388.9 nm, and those prepared with the 10-kDa filter had peaks in the spectra between 1,897.3 and 1,898.6 nm. The correlation coefficient (r2) between the NIR spectroscopy and high-performance liquid chromatography with cadaverine results was 0.98 to 0.99. We concluded that the biogenic amine content could be used to evaluate freshness in fish products, and that NIR measurements could be used to rapidly and accurately determine freshness.

NIR spectroscopy-multivariate analysis for discrimination and bioactive compounds prediction of different Citrus species peels.

Near Infrared (NIR) method combined with chemometrics was utilized to achieve the target of deeper insight into the chemical diversity and to discriminate the different species and chemovarieties of Citrus peels. Unsupervised principal component analysis (PCA) and hierarchical cluster analysis (HCA) were used for comparing of samples. A clear separation among the eight investigated species and cultivars was revealed, except for the red and white C. paradisi peels samples. Furthermore, fingerprint-bioflavonoids content relationship was modeled by partial least squares regression. A practical approach based on reflectance NIR measurements and partial least squares regression (PLSR) was demonstrated for quantitative determination of the bioflavonoids hesperidin and diosmin and compared to other reported methods. The regression coefficients (R2) between predicted values and pre-determined hesperidin and diosmin content were >0.98, indicating the possibility to simultaneously quantify hesperidin and diosmin in Citrus samples directly from NIR measurements using an adequate PLS regression. Citrus sinensis followed by Citrus reticulata samples were found the most enriched in the bioflavonoids hesperidin and diosmin. NIR-multivariate analysis can therefore be used for discrimination of different varieties and selection of citrus species with desired amounts of specific bioflavonoids which could successfully be analyzed in such complex plant matrices which can prove useful for further pharmaceutical implementation.

Optimal Estimation Retrieval of Aerosol Fine-Mode Fraction from Ground-Based Sky Light Measurements

In this paper, the feasibility of retrieving the aerosol fine-mode fraction (FMF) from ground-based sky light measurements is investigated. An inversion algorithm, based on the optimal estimation (OE) theory, is presented to retrieve FMF from single-viewing multi-spectral radiance measurements and to evaluate the impact of utilization of near-infrared (NIR) measurements at a wavelength of 1610 nm in aerosol remote sensing. Self-consistency tests based on synthetic data produced a mean relative retrieval error of 4.5%, which represented the good performance of the OE inversion algorithm. The proposed algorithm was also performed on real data taken from field experiments in Beijing during a haze pollution event. The correlation coefficients (R) for the retrieved aerosol volume fine-mode fraction (FMFv) and optical fine-mode fraction (FMFo) against AErosol RObotic NETwork (AERONET) products were 0.94 and 0.95 respectively, and the mean residual error was 4.95%. Consequently, the inversion of FMFv and FMFo could be well constrained by single-viewing multi-spectral radiance measurement. In addition, by introducing measurements of 1610 nm wavelength into the retrieval, the validation results showed a significant improvement in the R value for FMFo (from 0.89–0.94). These results confirm the high value of NIR measurements for the retrieval of coarse mode aerosols.

Age-related differences in frontal lobe function in children with ADHD

BackgroundThe neural correlates of executive function disorders are thought to be predominantly localized within the prefrontal cortex (PFC). However, no study to date has investigated changes in this system across different age groups in children with attention deficit hyperactivity disorder (ADHD). Thus, this study aimed to explore changes in PFC function in children with ADHD. MethodsStudy participants included typically developing (TD) children (n = 140) and children with ADHD (n = 67) of primary school age. Behavioral executive functions and their neural basis were evaluated between the TD children and children with ADHD and also across different age periods (younger and older children). To examine executive function, inhibitory control was assessed using the reverse Stroop task, and PFC near-infrared spectroscopic measurements were used to investigate the neural mechanisms involved. ResultsBoth ADHD symptoms and the ability to inhibit color interference improved with age. Compared to TD children, children with ADHD demonstrated decreased activation of the right and middle PFC across all age groups. Interestingly, the left PFC appeared to play a compensatory role. ConclusionChildren with ADHD exhibited changes in PFC function that varied with age. Longitudinal studies are required to assess the potential of using PFC function as an early biomarker of ADHD.

Delivery and Biodistribution of Traceable Polymeric Micellar Diclofenac in the Rat

The nonsteroidal anti-inflammatory drugs elevate cardiovascular risk, perhaps, due to their accumulation in the heart and kidneys. We designed nanodelivery systems for cardiotoxic diclofenac to reduce its presence in these organs. Diclofenac ethyl ester (DFEE) was encapsulated in traceable micelles based on poly(ethylene oxide)-b-poly(ε-caprolactone) (DFEE-PCL-TM) or poly(ethylene oxide)-b-poly(α-benzyl carboxylate-ε-caprolactone) (DFEE-PBCL-TM). Diclofenac pharmacokinetics and tissue distribution were studied after intravenous (iv) and intraperitoneal administration of the nanoformulations and compared with those after iv doses of free diclofenac (n = 3-6/group). The average diameters for DFEE-PBCL-TM and DFEE-PCL-TM were 37.2 ± 0.06 and 45.1 ± 0.06 nm, respectively. Drug concentration dropped below the assay sensitivity after free drug administration in 6 h, but persisted for 24 h following DFEE-PBCL-TM (2.3 ± 1.4 μg/mL) and DFEE-PCL-TM (1.9 ± 0.6 μg/mL) iv administration. The diclofenac heart:blood and kidney:blood ratios were 5- to 12-fold lower with the nanoformulations than with free diclofenac. Near-infrared fluorescence measurements in tissues suggested exposure patterns to nanocarriers parallel with those achieved for delivered diclofenac by nanoformulations. Administration of DFEE-PCL-TM by iv or intraperitoneal injection, resulted in comparable pharmacokinetics and 6 h postdose near-infrared fluorescence in the heart, kidneys, liver, and spleen. When compared to each other, DFEE-PBCL-TM showed significantly lower diclofenac levels in the heart compared to DFEE-PCL-TM (0.3 ± 0.03 vs. 0.5 ± 0.1 μg/g). Developed nanoformulations of diclofenac prolonged diclofenac circulation and reduced its presence in the heart and kidneys, strongly suggesting cardiac-safe delivery vehicles for diclofenac.