Total Intensities Research Articles

Polarisation results from the GOODS-N field with Apertif and polarised source counts

We analysed six Apertif datasets, covering the GOODS-N LOFAR deep field region, aiming to improve our understanding of the faint radio source composition, their polarisation behaviour, and how this affects our interpretation of polarised source counts. Using a semi-automatic routine, we ran rotation measure synthesis to generate a polarised intensity mosaic for each observation. The routine also performs source finding and cross-matching with the total power catalogue, as well as NVSS, SDSS and allWISE, to obtain a catalogue of 1182 polarised sources in an area of 47.4\,deg$^2$. Using the mid-infrared (MIR) radio correlation, we found no indication of any polarised emission from star formation. To robustly estimate the source counts, we performed an investigation of our sample's completeness as a function of the polarised flux via synthetic source injection. In contrast to previous works, we find no strong dependency of fractional polarisation on the total intensity flux density. We argue that differences regarding previous (small-scale, deep field) analyses can be attributed to sample variance. Relative to the findings of previous works, here we find a steeper slope for our Euclidean-normalised differential source counts. This is also visible as a flattening in cumulative source counts. We attribute the observed steeper slope in Euclidean normalised differential source counts to a change in the source composition and properties at low total intensities.

Visual research on spray and low temperature combustion of biodiesel/ethanol/water micro-emulsified fuels

To solve the negative environmental problems derived from the transport sector, this study is devoted to realizing a thorough substitution of biomass fuels for petroleum diesel. The spray, ignition, combustion, and emission of pure biodiesel, biodiesel/ethanol blend, and two kinds of biodiesel/ethanol/water triple micro-emulsified fuels were studied through optical visual methods on a constant volume combustion chamber. First of all, the micro-emulsified fuels obviously improve the spray quality. The micro-explosion effect of internal water improves the spray and atomization and the gas–liquid phase spray projected areas of microemulsion fuel at the maximum water blending ratio are the largest in the mid and late stages of spray. Secondly, with the increase of the water blending ratio, the combustion process of the fuel is improved. The flame lift-off length increases, the ignition delay period is prolonged, and the air entrainment effect is enhanced. Meanwhile, the combustion flame temperature decreases with the increase of water content, realizing low-temperature combustion. Lastly, the micro-emulsified fuels markedly decrease soot emissions. Both the total luminous intensities and normalized total KLs of micro-emulsified fuel with high water content are the lowest, achieving the best soot reduction effect. The triple micro-emulsified fuels have significant potential as a full biomass alternative fuel.

The carbon cost of impaired welfare on sheep farms.

In the face of global climate threats, farm and land-management decisions must balance climate concerns with profitability, animal welfare, and ecosystem health. However, few comprehensive studies have quantified the relationship between animal welfare and greenhouse gas (GHG) emissions, and no study focuses specifically on sheep farms. The present study aims to quantify the effects of impaired welfare on GHG emissions for common welfare challenges faced in UK lowland (L) and hill (H) sheep farming systems. Two case study research farms in Scotland, representative of high welfare conditions, were used as baselines for semi-intensive L and extensive H systems. In this study, "high welfare conditions" are defined as situations where animals have access to adequate feeding, suitable housing, good health, and opportunities to express natural behaviours. From each high-welfare baseline, scenarios representing common levels of impaired welfare conditions were modelled, using parameters retrieved from the published literature. The selected poor-welfare scenarios included lameness, gastrointestinal nematodes, blowfly strike, liver fluke, inadequate shelter provision, inadequate feeding during lamb growth and late gestation, and high lamb mortality rate. GHG emissions were estimated "from-cradle-to-farm-gate" using Agrecalc ©, a Life Cycle Assessment tool for the agricultural sector. Total GHG emissions and emission intensities (EI) in kg of CO2 equivalent per kg live weight were compared across the baseline and the scenarios. Gross farm emissions and product-level EIs demonstrated divergent patterns in response to impaired welfare. Most impaired welfare scenarios led to a slight decrease in total farm emissions (0.03-3%), with a few exceptions. On the other hand, EI increased across all impaired welfare scenarios relative to the baseline, because meat production decreased by 1.3-16.6% across all impaired welfare scenarios, reducing resource use efficiency. Lameness was identified as particularly impactful, resulting in 18 and 10% increases in EI on H and L farms, respectively. This was primarily due to the high lamb mortality associated with lameness in published studies. Inadequate shelter provision was associated with an 8-15% increase in EI. Scenarios related to ineffective parasite control contributed to an EI increase ranging from 1 to 13%, while inadequate feeding management caused a 3-4% increase in EI. This study highlights the potential for reducing emission intensity through system-specific interventions, emphasising the importance of integrating animal welfare into GHG mitigation strategies.

Study on Ozone and Its Critical Influencing Factors in Key Regions of China

Solar radiation is the fundamental energy source of climate change, which has a significant impact on the generations of secondary fine particulate matter (PM2.5) and ozone (O3) in the atmosphere. Additionally, surface solar radiation is also affected by the concentration of PM2.5, which in turn affects the generation of O3. To clarify the relationships among the O3, PM2.5 and the total radiation intensity, this study analyzes their temporal and spatial variation trends from 2017 to 2019. Meanwhile, as a common precursor of O3 and PM2.5, concentration variations in nitrogen dioxide (NO2) are discussed as well in this study. The results showed the following: (1) There are significant positive correlations between the O3-8h concentrations and the total radiation intensities in critical regions, especially in the “2 + 26” cities, Fen-Wei Plain and Yangtze River Delta. (2) The decrease in PM2.5 concentrations is in good agreement with the trend of NO2 concentrations, while the response of O3 concentration to the NO2 concentration variation differs in different regions, except in the Pearl River Delta. (3) In addition to the meteorological factors, changes in the concentrations and ratios of precursors such as NO2 and volatile organic compounds (VOCs) likely contribute to the observed fluctuations in O3 concentrations in recent years.

The CH3D Absorption Spectrum Near 1.58 μm: Extended Line Lists and Rovibrational Assignments.

Monodeuterated methane (CH3D) contributes greatly to absorption in the 1.58 μm methane transparency window. The spectrum is dominated by the 3ν2 band near 6430 cm-1, which is observed in natural methane and used for a number of planetary applications, such as the determination of the D/H ratio. In this work, we analyze the CH3D spectrum recorded by high-sensitivity differential absorption spectroscopy in the 6099-6530 cm-1 region, both at room temperature and at 81 K. Following a first contribution to this topic by Lu et al., the room-temperature line list is elaborated (11,189 lines) and combined with the previous 81 K list (8962 lines) in order to derive about 4800 empirical lower-state energy values from the ratio of the line intensities measured at 81 K and 294 K (2T-method). Relying on the position and intensity agreements with the TheoReTS variational line list, about 2890 transitions are rovibrationally assigned to twenty bands, with fifteen of them being newly reported. Variational positions deviate from measurements by up to 2 cm-1, and the band intensities are found to be in good agreement with measurements. All the reported assignments are confirmed by Ground-State Combination Difference (GSCD) relations; i.e., all the upper-state energies (about 1370 in total) have coinciding determinations through several transitions (up to 8). The energy values, determined with a typical uncertainty of 10-3 cm-1, are compared to their empirical and variational counterparts. The intensity sum of the transitions assigned between 6190 and 6530 cm-1 represents 76.9 and 90.0% of the total experimental intensities at 294 K and 81 K, respectively.

Neural and Muscular Determinants of Performance Fatigability Are Independent of Work and Recovery Durations During High-Intensity Interval Exercise in Males

ABSTRACT The present study aimed to investigate the effect of two protocols of high-intensity interval exercise (HIIE) on performance fatigability and its neural and muscular determinants. On different days, 14 healthy males performed two HIIE protocols with different work and recovery durations (matched for total duration, work and recovery intensities, and density): 1) 4 × 4 min at 90% HRpeak,180-s recovery at 70% HRpeak; and 2) 16 × 1 min at 90% HRpeak, 45-s recovery at 70% HRpeak. Pre- to post-HIIE reduction in maximal voluntary isometric contraction (MVIC) was used as marker of performance fatigability, while voluntary activation (VA) and potentiated quadriceps twitch force (Qtw) as markers of the neural (i.e. central fatigue) and muscular (i.e. peripheral fatigue) determinants, respectively. In addition, pre- to post-HIIE reduction in twitch force stimulated at 100 Hz (Qtw100) and 10:100 Hz ratio (Qtw10:Qtw100) were used as markers of high- and low-frequency performance fatigability, respectively. The MVIC, VA, Tw, Qtw100, and Qtw10:Qtw100 ratio decreased similarly from pre- to post-HIIE in both HIIE protocols (p < .05). The rating of perceived effort, blood pH, and plasma lactate responses were similar between HIIE protocols (p > .05), but the heart rate was higher in the longer HIIE protocol (p < .05). In conclusion, performance fatigability and its neural and muscular determinants seemed to be independent of the work and recovery durations of the HIIE, at least when HIIE protocols were matched for total work duration, work and recovery intensities, and density. Further, HIIE with long work and recovery might be preferable when the intention is to stress the chronotropic response.

Contrast enhancement of digital images using dragonfly algorithm

Contrast enhancement aims to amplify the visual quality of images by modifying the contrast level because digital images may get distorted by casual acquisition. The article deals with contrast enhancement as an optimization problem and uses the Dragonfly Algorithm (DA) to find the optimal grey-level intensity values. The DA for contrast enhancement uses five control parameters (entropy, number of edges, total intensities of edges, the variance of the probability of occurrence of each grey value, and the number of grey levels) to generate an objective function. An ablation study is also performed to understand how different controlling parameter combinations contribute to determining the optimal solution. The proposed approach considers 24 grey-scale images from the Kodak dataset and metrics as Peak Signal-to-Noise Ratio (PSNR), Visual Information Fidelity (VIF), and Structural Similarity Index Measure (SSIM) to verify the output's performance. The PSNR, VIF, and SSIM values in the experiments are 30.87, 0.7451, and 0.9523, respectively. The experimental observations reveal that the proposed DA-based image contrast enhancement produces high-quality images from its low-contrast counterparts. Comparisons with state-of-art methods ensure the superiority of the proposed algorithm. The Python implementation of the proposed approach is available in this Github repository.

Magnitude of obesity alone does not alter the alveolar lipidome.

Obesity may lead to pulmonary dysfunction through complex and incompletely understood cellular and biochemical effects. Altered lung lipid metabolism has been identified as a potential mechanism of lung dysfunction in obesity. Although murine models of obesity demonstrate changes in pulmonary surfactant phospholipid composition and function, data in humans are lacking. We measured untargeted shotgun lipidomes in two bronchoalveolar lavages (BALs) from apical and anteromedial pulmonary subsegments of 14 adult subjects (7 males and 7 females) with body mass indexes (BMIs) ranging from 24.3 to 50.9 kg/m2. The lipidome composition was characterized at the class, species, and fatty acyl/alkyl level using total lipid molecular ion signal intensities normalized to BAL protein concentration and epithelial lining fluid volumes. Multivariate analyses were conducted to identify potential changes with increasing BMI. The alveolar lipidomes contained the expected composition of surfactant-associated phospholipids, sphingolipids, and sterols in addition to cardiolipin and intracellular signaling lipid species. No significant differences in lipidomes were detected between the two BAL regions. Though a small number of lipid species were associated with BMI in multivariate analyses, no robust differences in lipidome composition or specific lipid species were identified over the range of body habitus. The magnitude of obesity alone does not substantially alter the alveolar lipidome in patients without lung disease. Differences in lung function in patients with obesity and no lung disease are unlikely related to changes in alveolar lipid composition.NEW & NOTEWORTHY Altered lung lipid metabolism has been identified as a potential mechanism of lung dysfunction in obesity, but data in humans are lacking. We measured the alveolar lipidome in bronchoalveolar lavages from subjects with healthy lungs with a wide range of body mass index. There were no differences in lipidome composition in association with the magnitude of obesity. In patients with healthy lungs, obesity alone does not alter the alveolar lipidome.

The ethylene absorption spectrum between 6075 and 8050 cm-1: Empirical line list and rovibrational assignments

The highly congested absorption spectrum of ethylene (C2H4) is analyzed between 6075 and 8050 cm-1. In the 6200–8050 cm-1 range, a list of about 32,650 lines is retrieved from a room temperature spectrum recorded by Fourier transform spectroscopy (P = 15.72 mbar, L = 45 m). This dataset was merged with a set of about 3460 lines available in the literature in the region of the strong ν5+ν9 band near 6150 cm-1. In addition, two FTS spectra at 130 K provide complementary information in the 6020–6320 cm-1 range (about 7570 lines).Relying on the position and intensity agreements with a line list of 12C2H4 transitions calculated by the variational method, a total of 4090 transitions is assigned to eighteen bands, ten of them being newly reported. All the reported assignments are confirmed by Lower State Combination Difference (LSCD) relations i.e. all the upper states (1749 in total) have coinciding determinations of their energies through several transitions (up to 6). The obtained empirical energy values are given and compared to their variational counterpart. As an additional validation test of the lower state assignments, the room temperature intensities are extrapolated at 130 K and compared to their experimental values. Overall, a large fraction of the strong lines of the region is assigned and the total intensity of the assigned transitions represents 46 and 55% of the total variational and experimental intensities at 296 K, respectively. In the considered range, variational positions deviate from measurements by a few cm-1 and the total variational absorption is underestimated by 40 %.

Mapping the Functional Structure of Urban Agglomerations at the Block Level: A New Spatial Classification That Goes beyond Land Use

The functional structure of territorial space is an important factor for analyzing the interaction between humans and nature. However, the classification of remote sensing images struggles to distinguish between multiple functions provided by the same land use type. Therefore, we propose a framework to combine multi-source data for the recognition of dominant functions at the block level. Taking the Guangdong–Hong Kong–Macau Greater Bay Area (GBA) as a case study, its block-level ‘production–living–ecology’ functions were interpreted. The whole GBA was first divided into different blocks and its total, average, and proportional functional intensities were then calculated. Each block was labeled as a functional type considering the attributes of human activity and social information. The results show that the combination of land use/cover data, point of interest identification, and open street maps can efficiently separate the multiple and mixed functions of the same land use types. There is a great difference in the dominant functions of the cities in the GBA, and the spatial heterogeneity of their mixed functions is closely related to the development of their land resources and socio-economy. This provides a new perspective for recognizing the spatial structure of territorial space and can give important data for regulating and optimizing landscape patterns during sustainable development.

Probing nitro(so) and chloro byproducts and their precursors in natural organic matter during UV/NH2Cl treatment by FT-ICR MS with machine learning insights

The UV/monochloramine (UV/NH2Cl) process, while efficiently eliminating micropollutants, produces toxic byproducts. This study utilized Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) to investigate molecular-level changes in natural organic matter (NOM) and to disclose formation pathways of nitro(so) and chloro byproducts in the UV/NH2Cl process. The UV/NH2Cl process significantly increased the saturation and oxidation levels and altered the elemental composition of NOM. Using 15N labeling and a screening workflow, nitro(so) byproducts with nitrogen originating from inorganic sources (i.e., reactive nitrogen species (RNS) and/or NH2Cl) were found to exhibit total intensities comparable to those from NOM. RNS, rather than NH2Cl, played a significant role in incorporating nitrogen into NOM. Through linkage analysis, nitro(so) addition emerged as an important reaction type among the 25 reaction types applied. By using phenol as a representative model compound, the nitro byproducts were confirmed to be mainly generated through the oxidation of nitroso byproducts instead of nitration. Machine learning and SHAP analysis further identified the major molecular indices distinguishing nitro(so) and chloro precursors from non-precursors. This study enhances our fundamental understanding of the mechanisms driving the generation of nitro(so) and chloro byproducts from their precursors in complex NOM during the UV/NH2Cl process.

Parameters of differential equations in four-flux and two-flux models approximated for scattering and absorption results on solar thermal collector black paints

Abstract The intrinsic and extrinsic scattering and absorption coefficients of a thin black paint substrate used as a solar thermal collector, deposited on a thick glass substrate, were obtained in an approximated single-layer method, using the new solved equations recently determined from the collimated and diffuse differential equations of the four-flux model, for the intrinsic coefficients, and considering the differential equations of the two-flux model with total light intensities, for the extrinsic coefficients. In a first step, the optical constants were determined from the measurements of regular transmittance and specular reflectance, fitting them to the collimated transmittance and reflectance solutions of the four-flux model. In a second step, the intrinsic coefficients were obtained from the diffuse transmittance and reflectance measurements, considering four forward scattering ratios (for collimated and diffuse light intensities and for forward and backward light directions) and two average crossing parameters (for forward and backward light directions). In a third step, the extrinsic coefficients were obtained, using the new solved equations recently determined considering the total differential equations as the sum of the collimated and diffuse differential equations. Due to the approximated single-layer method, a simple rule of three was applied to the intrinsic and extrinsic results, relating the extinction coefficients calculated from the optical constants to those calculated from the collimated differential equations. The same external and internal diffuse interface reflectance was observed by integrating the collimated interface reflectance up to the critical angle of total internal reflection.

A Meta-Analysis of the Effects of Dietary Yeast Mannan-Rich Fraction on Broiler Performance and the Implication for Greenhouse Gas Emissions from Chicken Production.

Dietary supplementation of yeast-derived mannan-rich fraction (MRF) could improve the gastrointestinal health and production efficiency of broilers, and, consequently, lower the environmental impacts of chicken production. The objective of this meta-analysis was to quantify the retrospective effects of feeding MRF (Actigen®, Alltech Inc., Nicholasville, KY) on the production performance of broilers. The meta-analysis database included 27 studies and consisted of 66 comparisons of MRF-supplemented diets vs. basal (i.e., negative control) and antibiotic-supplemented (i.e., positive control) diets. A total of 34,596 broilers were involved in the comparisons and the average final age of the birds was 35 days. Additionally, the impact of feeding MRF on the carbon footprint (feed and total emission intensities) of chicken production was evaluated using the meta-analysis results of broiler performance (MRF vs. basal diets) to develop a scenario simulation that was analyzed by a life cycle assessment (LCA) model. A database of all trials (MRF vs. basal and antibiotic diets) indicated that feeding MRF increased (p < 0.01) average daily feed intake (ADFI; +3.7%), final body weight (FBW; +3.5%), and average daily gain (ADG; 4.1%) and improved (p < 0.01) feed conversion ratio (FCR; -1.7%) without affecting (p > 0.05) mortality. A subdatabase of MRF vs. basal diets indicated that dietary MRF increased ADFI (+4.5%), FBW (+4.7%), and ADG (+6.3%) and improved FCR (-2.2%) and mortality (-21.1%). For the subdatabase of MRF vs. antibiotic diets, both treatments exhibited equivalent effects (p > 0.05) on broiler performance parameters, suggesting that MRF could be an effective alternative to in-feed antibiotics. Subgroup analysis revealed that different study factors (year of study, breed/strain, production challenges, and MRF feeding duration) influenced the effect of dietary MRF on broiler performance. Simulated life cycle analysis (LCA) indicated that feeding MRF decreased feed and total emission intensities, on average, by -2.4% and -2.1%, respectively. In conclusion, these results demonstrate that dietary MRF is an effective nutritional solution for improving broiler performance, an effective alternative to in-feed antibiotic growth promoters, and reduces the environmental impact of poultry meat production.

Molecular Characterization of Gaseous Organic Acids and Nitrogen‐Containing Compounds From Crop Straw and Wood Burning

AbstractBiomass burning serves as important sources of volatile organic compounds (VOCs), yet our understanding of the molecular characteristics of oxygenated volatile organic compounds (OVOCs) from fresh emissions remains limited. In this study, gaseous organic compounds in fresh smokes from burning typical Chinese crop straws and woods are measured using an iodide time‐of‐flight chemical ionization mass spectrometer. Approximately 750 molecular formulas are identified, with CHO compounds containing carbon, hydrogen and oxygen atoms accounting for 77%–95% of the total. C1–C3 organic acids and dicarboxylic acids dominate the total CHO signal intensities by 27%–48%, while well‐known molecular markers of biomass burning, such as monosaccharide, guaiacol and syringol derivatives, contribute 7%–17%. Notably, crop straw and wood burning emit a higher abundance of guaiacol than syringol derivatives by a factor of 5. Additionally, a variety of nitrogen‐containing compounds (mainly in the CHON group) is identified, including isocyanate, amide, amino acids, and pyridine. The mass spectral profiles of organic compounds are largely similar between crop straw and wood burning fuels, although wood burning produces higher contributions of compounds with carbon atoms numbers &gt;10. The saturation concentrations of organic compounds are estimated using molecular formula‐based volatility parameterization, revealing that semi‐volatile and intermediate VOCs (S/intermediate volatility organic compounds (IVOCs)) predominate smoke releases by 35%–60% and 20%–43%, respectively, with only a small fraction of low‐volatility compounds. Given the widespread nature of biomass burning in winter China, our results may have significant implications for interpreting secondary organic aerosol formation through gas‐particle partitioning or aqueous‐phase reactions.

Forced Degradation Products of Olmesartan Medoxomil and their In Vitro Genotoxicity Assessment by Comet Assay using HEK Cells

AbstractThis study designed to characterize major forced degradation products of Olmesartan Medoxomil (OM) and to perform genotoxicity profiling using acid, base, and hydrogen peroxide‐induced stress degradation studies. The isolation of degradation products was conducted on flash chromatography using FlashPure ECOFLEX C18 4 g column with gradient elution and diode array detection‐based fraction collection, and characterized by mass spectrometry. Three impurities (impurity‐1, 2, and 3) were identified with respective m/z values of 447.213, 461.229, and 463.208. The genotoxic potential of impurities was assessed by in silico prediction, and in vitro comet assay using HEK cells. The extent of DNA damage was analyzed using Comet Assay IV imaging software. For impurity‐1, head and tail lengths and their respective total intensities were significantly (p&lt;0.001) larger than those of dimethyl sulfoxide (solvent) control and comparable to positive control. Other parameters such as mean grey level and total area of comet were statistically significant as compared with the solvent and positive controls. Overall, impurity‐1 was a possible genotoxic impurity and a known major degradation product in OM tablet dosage form. In silico prediction also revealed impurity‐1 as toxicity class 3, whilst impurities 2 and 3 were of toxicity class 4.

Improvements in digital meteor spectra reduction

This study addresses the complexity and importance of developing a method of calibrating digital observations of meteor spectra with all-sky cameras. It aims to present novel approaches to spectral sensitivity, atmospheric extinction and flat-field corrections. Images of a known line emission spectrum were captured at various positions within the field of view using a camera with a fish-eye lens and plastic holographic grating. The flat-field correction was separated into a wavelength-independent and wavelength-dependent component, both dependent on the position of the spectral line in the field of view (FoV). Total profile intensities of spectra obtained from the images were compared throughout the spectral range at different positions in the FoV. The flat-field was constructed by fitting those dependencies with high-degree polynomial functions. Using a simplified atmospheric model, a novel approach was constructed to determine the atmospheric extinction curve throughout the spectral range, allowing it to be separately considered from the spectral sensitivity which was previously not the case. A comparison of the newly developed and previously used methodology was tested on several meteor spectra of the same meteor captured from different stations of the European Fireball Network. It revealed a significantly improved correspondence of the analysed spectra in the part of the spectral range unaffected by the limitations imposed by the newly developed methodology. Failing to follow the correct calibration methodology precisely may introduce varying degrees of uncertainty in computations of elemental abundances and other physical properties, depending on the equipment’s specific effect magnitude.

Taxonomy of hybridly polarized Stokes vortex beams.

Structured beams carrying topological defects, namely phase and Stokes singularities, have gained extensive interest in numerous areas of optics. The non-separable spin and orbital angular momentum states of hybridly polarized Stokes singular beams provide additional freedom for manipulating optical fields. However, the characterization of hybridly polarized Stokes vortex beams remains challenging owing to the degeneracy associated with the complex polarization structures of these beams. In addition, experimental noise factors such as relative phase, amplitude, and polarization difference together with beam fluctuations add to the perplexity in the identification process. Here, we present a generalized diffraction-based Stokes polarimetry approach assisted with deep learning for efficient identification of Stokes singular beams. A total of 15 classes of beams are considered based on the type of Stokes singularity and their associated mode indices. The resultant total and polarization component intensities of Stokes singular beams after diffraction through a triangular aperture are exploited by the deep neural network to recognize these beams. Our approach presents a classification accuracy of 98.67% for 15 types of Stokes singular beams that comprise several degenerate cases. The present study illustrates the potential of diffraction of the Stokes singular beam with polarization transformation, modeling of experimental noise factors, and a deep learning framework for characterizing hybridly polarized beams.

Seasonal changes in water-soluble brown carbon (BrC) at Nanling background station in South China

Brown carbon (BrC) is an important light-absorbing component of organic carbon (OC), causing large uncertainty in aerosol radiative forcing evaluation and being related to health issues as well. Knowledge of BrC in an atmospheric background station is beneficial to understand its role in a changing climate. A year-long sampling campaign was conducted at Nanling background station to get a comprehensive knowledge of WS-BrC, a total of seventy-two PM2.5 samples throughout a year were used. Light absorption and fluorescence spectra of WSOC were analyzed synchronously using a fluorescence spectrophotometer. The low levels of PM2.5, OC, and elemental carbon (EC) conferred a background site. The optical properties of WS-BrC were characterized using excitation-emission matrix (EEM) fluorescence spectroscopy. The WS-BrC made a significant contribution (365 nm, 18% ± 10%) to total carbonaceous aerosol absorption. The mass absorption efficiency (MAE) of WS-BrC is 0.81 ± 0.34 m2 gC–1, and varies among seasons due to the different sources or atmospheric processing. Three EEM fluorescent components were identified by parallel factor (PAFAFAC) analysis, including two humic-like substances (HULIS, C1, C2), and one phenolic-like component. The HULIS components accounted for approximately 70% of the total fluorescence intensities. Primary combustion emissions showed enhanced activity during the winter and spring seasons, but there were no significant influences on WS-BrC in spring. Secondary sources contributed significantly to WS-BrC during winter, summer, and autumn (all exceeding 50%), except for spring. Photooxidation is a significant process in the formation of secondary WS-BrC in winter and autumn, but there may be another formation pathway in summer, i.e., the ammonia pathway. This study contributes to our understanding of BrC in the background atmosphere.

Novel 40 µm spot size 3050/3200 nm DFG laser versus CO2 laser for laser-assisted drug delivery.

The use of ablative fractional lasers to enhance the delivery of topical drugs through the skin is known as laser-assisted drug delivery. Here, we compare a novel 3050/3200 nm difference frequency generation (DFG) fiber laser (spot size: 40 µm) to a commercially used CO2 laser (spot size: 120 µm). The objective is to determine whether differences in spot size and coagulation zone (CZ) thickness influence drug uptake. Fractional ablation was performed on ex-vivo human abdominal skin with the DFG (5 mJ) and CO2 (12 mJ) lasers to generate 680 µm deep lesions. To evaluate drug delivery, 30 kDa encapsulated fluorescent dye was topically applied to the skin and histologically analyzed at skin depths of 100, 140, 200, 400, and 600 µm. Additionally, transcutaneous permeation of encapsulated and 350 Da nonencapsulated dye was assessed using Franz Cells. The DFG laser generated smaller channels (diameter: 56.5 µm) with thinner CZs (thickness: 22.4 µm) than the CO2 laser (diameter: 75.9 µm, thickness: 66.8 µm). The DFG laser treated group exhibited significantly higher encapsulated dye total fluorescence intensities after 3 h compared to the CO2 laser treated group across all skin depths (p < 0.001). Permeation of nonencapsulated dye was also higher in the DFG laser treated group vs the CO2 laser treated group after 48 h (p < 0.0001), while encapsulated dye was not detected in any group. The DFG laser treated skin exhibited significantly higher total fluorescence uptake compared to the CO2 laser. Additionally, the smaller spot size and thinner CZ of the DFG laser could result in faster wound healing and reduced adverse effects while delivering similar or greater amount of topically applied drugs.

Optical nondegenerate solitons in a birefringent fiber with a 35 degree elliptical angle.

In this paper, we investigate the optical nondegenerate solitons in a birefringent fiber with a 35 degree elliptical angle. We derive the nondegenerate bright one- and two-soliton solutions by solving the coupled Schrödinger equation. The formation of nondegenerate solitons is related to the wave numbers of the solitons, and we further demonstrate that it is caused by the incoherent addition of different components. We note that the interaction between two degenerate solitons or a nondegenerate soliton and a degenerate soliton is usually inelastic. This is led to the incoherent interaction between solitons of different components and the coherent interaction between solitons of the same component. Through the asymptotic analysis, we find that the two degenerate solitons are elastic interactions under certain conditions, and analyzed the influence of the Kerr nonlinear intensity coefficient γ and the second-order group velocity dispersion β2 in this system on solitons: the velocity and amplitude of the solitons are proportional to |β2|, while the amplitude of the solitons is inversely proportional to γ. Two nondegenerate solitons are elastic interactions, but the phase of the soliton can be adjusted to make it inelastic. Furthermore, regardless of the situation mentioned above, total intensities of the solitons before the interaction are equal to that after the soliton interaction.