Variable Absorption Research Articles

Population of excited levels of Fe+, Ni+, and Cr+ in exocomets’ gaseous tails

The star β Pictoris is widely known for harbouring a large population of exocomets, which create variable absorption signatures in the stellar spectrum as they transit the star. Although the physical and chemical properties of these objects have long been elusive, the recently developed exocomet curve of growth technique has, for the first time, enabled estimates of exocometary column densities and excitation temperatures, based on absorption measurements in mutliple spectral lines. Using this new tool, we present a refined study of a β Pic exocomet observed on December 6, 1997 with the Hubble Space Telescope. We first show that the comet’s signature in Fe II lines is well explained by the transit of two gaseous components, with different covering factors and opacities. Then, we show that the studied comet is detected in the lines of other species, such as Ni II and Cr II. These species are shown to experience similar physical conditions as Fe II (same radial velocity profiles and same excitation temperatures), hinting that they are well mixed. Finally, using almost 100 Fe II lines rising from energy levels between 0 and 33 000 cm–1, we derive the complete excitation diagram of Fe+ in the comet. The transiting gas is found to be populated at an excitation temperature of 8190 ± 160 K, very close to the stellar effective temperature (8052 K). Using a model of radiative and collisional excitation, we show that the observed excitation diagram is compatible with a radiative regime, associated with a close transit distance (≤60 R⋆ ∼ 0.43 au) and a low electronic density (≤107 cm–3). In this regime, the excitation of Fe+ is controlled by the stellar flux, and does not depend on the local electronic temperature or density. These results allow us to derive the Ni+/Fe+ and Cr+/Fe+ ratios in the December 6, 1997 comet, at 8.5 ± 0.8 ⋅ 10–2 and 1.04 ± 0.15 ⋅10–2, respectively, close to solar abundances.

Ionospheric Absorption Variation Based on Ionosonde and Riometer Data and the NOAA D-RAP Model over Europe During Intense Solar Flares in September 2017

A novel method was developed based on the amplitude data of the EM waves measured by Digisondes to calculate and investigate the relative ionospheric absorption changes. The effect of 13 solar flares (>C8) that occurred from 4 to 10 September 2017 were studied at three European Digisonde stations (Juliusruh (54.63°N, 13.37°E), Průhonice (49.98°N, 14.55°E) and San Vito (40.6°N, 17.8°E)). The present study compares the results of the amplitude method with the absorption changes measured by the Finnish Riometer Network and determined by the NOAA D-RAP model during the same events. The X-class flares caused 1.5–2.5 dB of attenuation at 30–32.5 MHz based on the riometer data, while the absorption changes were between 10 and 15 dB in the 2.5–4.5 MHz frequency range according to the amplitude data. The impact caused by energetic particles after the solar flares are clearly seen in the riometer data, while among the Digisonde stations it can be observed only at Juliusruh in some certain cases. Comparing the results of the amplitude method with the D-RAP model it seems evident that the observed absorption values almost always exceed the values given by the model both at 2.5 MHz and at 4 MHz during the investigated period. According to the comparison between the riometer data with the D-RAP, generally, the model underestimates the absorption values obtained from the riometers during solar flares except at the highest latitude stations, while D-RAP overestimates the impact during the particle events.

Studying the X-ray absorption characteristics of Centaurus X-3 using nearly 14 years of MAXI/GSC data

Centaurus X-3 is a persistent high-mass X-ray binary with the long-term light curve from the source exhibiting orbit-to-orbit intensity variations with no apparent superorbital periodicity. We used sim 13.5 years of MAXI /GSC data to study the long-term behaviour of X-ray absorption caused by the stellar wind from the companion star and any absorbing structures present in the binary. We used orbital-phase-resolved spectroscopy to study the variation in the photoelectric absorption along the line of sight of the source for both the intensity-averaged data and intensity-resolved data after dividing all the data binned with orbital period into three intensity levels. We find an asymmetric variation in the photoelectric absorption along the line of sight across an orbit of the source. The orbital-phase-resolved spectra show a clear increase in photoelectric absorption after $ orb 0.5, which deviates from a spherically symmetric stellar wind model. The flux of Cen X-3 shows significant variation between consecutive orbits. An intensity-resolved spectral analysis of the source was performed, followed by an intensity-resolved and orbital-phase-resolved spectral analysis, which showed that at the medium and high intensity levels, the orbital-phase-resolved photoelectric absorption is slightly asymmetric with respect to mid-phase ($ orb =$ 0.5). The asymmetry is very pronounced at the lowest intensity level and cannot be explained by a spherically symmetric wind from the companion star. The differences in the orbital phase-dependence of absorption for different intensity levels suggest that the presence of an accretion wake, photoionization wake, or tidal stream is more prominent at a lower intensity level for Centaurus X-3 than at a higher intensity level.

Spatiotemporal Sensitive Network for Non-Contact Heart Rate Prediction from Facial Videos

Heart rate (HR) is an important indicator reflecting the overall physical and mental health of the human body, playing a crucial role in diagnosing cardiovascular and neurological diseases. Recent research has revealed that variations in the light absorption of human skin captured through facial video over the cardiac cycle, due to changes in blood volume, can be utilized for non-contact HR estimation. However, most existing methods rely on single-modal video sources (such as RGB or NIR), which often yield suboptimal results due to noise and the limitations of a single information source. To overcome these challenges, this paper proposes a multimodal information fusion architecture named the spatiotemporal sensitive network (SS-Net) for non-contact heart rate estimation. Firstly, spatiotemporal feature maps are utilized to extract physiological signals from RGB and NIR videos effectively. Next, a spatiotemporal sensitive (SS) module is introduced to extract useful physiological signal information from both RGB and NIR spatiotemporal maps. Finally, a multi-level spatiotemporal context fusion (MLSC) module is designed to fuse and complement information between the visible light and infrared modalities. Then, different levels of fused features are refined in task-specific branches to predict both remote photoplethysmography (rPPG) signals and heart rate (HR) signals. Experiments conducted on three datasets demonstrate that the proposed SS-Net achieves superior performance compared to existing methods.

Remote physiological signal recovery with efficient spatio-temporal modeling.

Contactless physiological signal measurement has great applications in various fields, such as affective computing and health monitoring. Physiological measurements based on remote photoplethysmography (rPPG) are realized by capturing the weak periodic color changes. The changes are caused by the variation in the light absorption of skin surface during systole and diastole stages of a functioning heart. This measurement mode has advantages of contactless measurement, simple operation, low cost, etc. In recent years, several deep learning-based rPPG measurement methods have been proposed. However, the features learned by deep learning models are vulnerable to motion and illumination artefacts, and are unable to fully exploit the intrinsic temporal characteristics of the rPPG. This paper presents an efficient spatiotemporal modeling-based rPPG recovery method for physiological signal measurements. First, two modules are utilized in the rPPG task: 1) 3D central difference convolution for temporal context modeling with enhanced representation and generalization capacity, and 2) Huber loss for robust intensity-level rPPG recovery. Second, a dual branch structure for both motion and appearance modeling and a soft attention mask are adapted to take full advantage of the central difference convolution. Third, a multi-task setting for joint cardiac and respiratory signals measurements is introduced to benefit from the internal relevance between two physiological signals. Last, extensive experiments performed on three public databases show that the proposed method outperforms prior state-of-the-art methods with the Pearson's correlation coefficient higher than 0.96 on all three datasets. The generalization ability of the proposed method is also evaluated by cross-database and video compression experiments. The effectiveness and necessity of each module are confirmed by ablation studies.

Relieving postherpetic neuralgia pain via gabapentin-loaded bigels as an auspicious topical drug delivery system.

Over the past decades, a substantial portion of the population worldwide has been infected with varicella zoster and most cases developed shingles. Unfortunately, shingles is usually accompanied by postherpetic neuralgia, which may persist for months to years after the resolution of the viral infection. Gabapentin is an orallygamma-aminobutyric acid analogue approved by the Food and Drug Administration to manage shingles postherpetic neuralgia. However, gabapentin shows nonlinear pharmacokinetics, with variable absorption and bioavailability along with its short half-life and long side effects that may include dizziness and somnolence, which calls for an appropriate topical dosage form. Bigels are unique semisolid dosage forms with boosted penetrability and satisfactory hydrophilic texture. The current work pointed to formulating gabapentin-loaded bigels for the treatment of postherpetic neuralgia, where the analysis and optimization of design were performed via Design-Expert®. The selected bigel (F5), incorporating 400mg Span 60, 1000mg Tween 80, and 1000mg Transcutol, displayed spherical nanosized particles with acceptable viscosity and spreadability. Subsequent topical application of the selected bigel on the skin of Wistar rats, F5, demonstrated a boosted accumulation of gabapentin in the skin similar to PLO gel but superior to the drug solution. Furthermore, a histopathological study demonstrated the biosafety of the selected bigel when applied topically. Accordingly, gabapentin-loaded bigel would be considered a potentially topical dosage form for the delivery of gabapentin for the management of postherpetic neuralgia.

Building Energy Savings and Power Output Augmentation of Roof Mounted PV Using Co-Located Rooftop Reflectors

Abstract Photovoltaic panels (PVs) installed on building rooftops yield a positive influence on the thermal performance of the building due to the shading of the PV panels, decreasing cooling loads while causing a smaller increase in heating loads. Additionally, the electrical power output of PV panels has been shown to be increased by including reflectors between PV rows, concentrating the solar flux onto the active portion of the panels. When implemented into the spaces between the rows of a roof-mounted PV array, reflectors might further improve the positive thermal effects of rooftop installed PV arrays. This work focuses on predicting rooftop heat flux and temperature for a building rooftop equipped with PV panels and reflectors. The Saved Energy Load (SEL), Additional Energy Load (AEL), PV power output, rooftop heat flux and the utility factor (ratio of positive building energy impacts to negative building energy impacts) are reported parametrically for variations in the rooftop absorptivity and reflector area for three United States locations. Utility factors of 375, 140 and 160 are found for Phoenix, Boise and Dayton, respectively, for a reflector covering the full area between panels with a roof having a minimal absorptivity. A building in Phoenix exhibits a 15% increase in the utility factor of the PV-building system when reflectors are incorporated compared against a PV-building system without reflectors, while a building in Dayton showed a 22% increase in utility factor when reflectors are included between the rows of a roof-mounted PV array.

Visualizing Thermally Activated Conical Intersections Governing Non-Radiative Triplet Decay in a Ni(II) Porphyrin-Nanographene Conjugate with Variable Temperature Transient Absorption Spectroscopy.

Metalloporphyrins based on open-shell transition metals, such as Ni(II), exhibit typically fast excited-state relaxation. In this work, we shed light into the nonradiative relaxation mechanism in a nanographene-Ni(II) porphyrin conjugate. Variable temperature transient absorption and global fit analysis are combined to produce a picture of the relaxation pathways. At room temperature, photoexcitation of the lowest π-π* transition is followed by vibrational cooling in 1.6 ps, setting a short 20 ps temporal window wherein a small fraction of relaxed singlets radiatively decay to the ground state before intersystem crossing proceeds. Following intersystem crossing, triplets relax rapidly to the ground state (S0) in a few tens of picoseconds. By performing measurements at low temperature, we provide evidence for a competition between two terminal relaxation pathways from the lowest (metal-centered) triplet to the ground state: a slow ground state relaxation process proceeding in time scales beyond 1.6 ns and a faster pathway dictated by a sloped conical intersection, which is thermally accessible at room temperature from the triplet state. The overall triplet decay at a given temperature is dictated by the interplay of these two contributions. This observation bears significance in understanding the underlying fast relaxation processes in Ni-based molecules and related transition metal complexes, opening avenues for potential applications for energy harvesting and optoelectronics.

8205 Within day Symptoms Of Adrenal Insufficiency Predict Reduced Quality Of Life And Adrenal Crises In 712 MyAI Registry Participants

Abstract Disclosure: J.G. Kallet: None. W. Hover: None. A. Krein: None. M. Lowe: None. M.F. Slovick: None. G. Kinney: None. S. Majka: None. K. Warren: None. S. Watts: None. M.T. McDermott: None. E.A. Regan: None. Multiple studies have shown reduced quality of life in people with adrenal insufficiency based on 1- 4 week recall of symptoms. However, “within-day” symptoms are commonly reported to treating physicians, and there is no clear understanding of what these symptoms represent for quality of life or adequate disease management. Lack of adequate cortisol has been postulated as a factor for both persistent symptoms and reduced quality of life but dose adjustment is not typically prescribed. Within-day symptoms are similar to those reported prior to treatment, and include lack of energy, nausea, vomiting, anorexia, headache, dizziness, shakiness, muscle cramps, and cognitive impairments. Addressing the relationship between “within-day” symptoms and replacement dosing could improve disease management. Further, understanding the association of within-day symptoms to outcomes (quality of life and adrenal crises) provides an impetus to change the standard of care. Individuals enrolled in the MyAI registry provided information about “within-day” symptoms. These included energy to accomplish tasks, cognitive symptoms, and overall symptoms. The questions were scored with increased values representing greater and more frequent symptoms and were summed to create a severity score. Patients also reported adrenal crisis within the past year and completed the AddiQoL as quality of life over the past 4 weeks.Responses were obtained from 712 adult registry participants - 84% female, age range 23-89, mean 51.2 (15.2) years - and 47% reported an adrenal crisis within the past year. Within-day symptom score range was 3-15 points with mean 7.9 and SD of 2.96. Higher “within-day” symptom scores were associated with stepwise reductions in the AddiQoL (worse quality of life). Individuals who reported an adrenal crisis within the past year had significantly increased symptom scores [8.8 (2.9) vs 6.7 (2.5), p<0.0001]. Regression model for the AddiQoL total score (R2 = 0.8) found after adjusting for group, age and sex, that BMI (p = 0.0002) and symptom score (p<0.0001) were highly significant predictors of worse AddiQoL score. ConclusionAdrenal crisis is reported frequently by patients who are being treated for adrenal insufficiency. We found a strong association of “within-day” symptoms to both risk of adrenal crisis and reduced quality of life. Addressing persistent disease-related symptoms in adrenal insufficiency would be an appropriate disease management response to improve care. The initial choice of replacement dosing based on body surface area or other metric may be a starting point for care but should be informed by studies that show large variation in absorption and metabolism between individuals. Adjusting doses of replacement hormones and careful management of adrenal insufficiency symptoms could improve outcomes. Presentation: 6/1/2024

Compact multilayer selective absorbers based on amorphous carbon for solar-thermal conversion

In addressing the energy crisis and climate change, environmentally sustainable materials and structures with heightened absorption and enhanced photothermal conversion efficiency are urgently demanded. In this study, a series of ultrabroadband, omnidirectional, and near-perfect solar radiation absorbers based on amorphous carbon (a-C) were fabricated by magnetron sputtering. These absorbers, featuring 4, 6, and 8-layer compact multilayer thin film structures, exhibited measured absorption of 96.8 %, 96.5 %, and 96.6 % in the range of 300–2500 nm, respectively. The high absorption efficiency delves into the synergistic effects of intrinsic absorption of a-C and enhanced absorption through thin film interference. Through microstructure analysis, the reduced absorption compared to design originates from the optical thickness mismatch caused by the unstable growth rate of a-C. In addition, the absorbers show very slight variations in absorption within 40° and maintain a high absorption of more than 80 % in the incident angle of 60°. For samples with different air annealing temperatures from 100 to 250 °C, the microstructure, morphology, and optical properties were systematically investigated. The appearance of oxygen channels due to surface defects or voids leads to the oxidation reaction of the diffused Ti atoms at high temperature. Notably, the proposed absorber can be fabricated by a lithography-free method, paving a way for large-area application of a-C.

Two‐Dimensional Solidification Simulation of PCM Molten Salt as a Thermal Energy Storage for Stirling Engine

ABSTRACTThermal energy storage technologies have been widely used to mitigate intermittency from renewable energy sources such as solar energy. Phase change material (PCM) is a material that can be used as a heat storage medium and is available in a wide range of operating temperatures. Molten salt is one of the PCMs that has the advantage of a very high operating temperature. The PCM solidification simulation based on HitecXL molten salt using COMSOL Multiphysics software was carried out with variations in heat absorption of 1–5 kW/m2, assuming constant heat absorption. The results showed that the PCM solidification process started from the surface of the Stirling engine heat exchanger pipe. The part of the PCM that is solidified falls due to gravity, causing a phenomenon similar to a droplet. The flow that occurred was natural, driven by the buoyancy force resulting from density changes due to temperature gradients in the solidification process. The time required for the PCM to completely solidify was closely related to the amount of heat absorption; the greater the heat absorption from the pipe, the faster the PCM is fully solidified.

The Remarkable X-Ray Spectra and Variability of the Ultraluminous Weak-line Quasar SDSS J1521+5202

We present a focused X-ray and multiwavelength study of the ultraluminous weak-line quasar (WLQ) SDSS J1521+5202, one of the few X-ray weak WLQs that is amenable to basic X-ray spectral and variability investigations. J1521+5202 shows striking X-ray variability during 2006–2023, by up to a factor of ≈32 in 0.5–2 keV flux, and our new 2023 Chandra observation caught it in its brightest X-ray flux state to date. Concurrent infrared/optical observations show only mild variability. The 2023 Chandra spectrum can be acceptably described by a power law with intrinsic X-ray absorption, and it reveals a nominal intrinsic level of X-ray emission relative to its optical/ultraviolet emission. In contrast, an earlier Chandra spectrum from 2013 shows apparent spectral complexity that is not well fit by a variety of models, including ionized absorption or standard Compton-reflection models. Overall, the observations are consistent with the thick-disk plus outflow model previously advanced for WLQs, where a nominal level of underlying X-ray emission plus variable absorption leads to the remarkable observed X-ray variability. In the case of J1521+5202, it appears likely that the outflow, and not the thick disk itself, lies along our line of sight and causes the X-ray absorption.

Nanoemulsion-based transdermal delivery of third-generation steroidal and non-steroidal aromatase inhibitors in preclinical models.

Aromatase inhibitors are effective in treating hormone receptor-positive breast cancer, particularly in postmenopausal women. However, the challenges of inconsistent dissolution, variable absorption and side effects with oral administration persist. To address these issues, transdermal delivery has emerged as a viable alternative. In our study, we have developed nanoemulsion-based transdermal creams containing third-generation aromatase inhibitors Exemestane (EXE) or Letrozole (LE) and evaluated their toxicity, anti-tumour effects and androgenic potency using preclinical models including Bama minipigs, DMBA-induced breast cancer rats and orchidectomized male rats. The results of our study are significant, suggesting that both creams effectively penetrated the skin, demonstrating an impressive anti-breast cancer effect. Importantly, EXE cream had no organ toxicity at the tested dose, providing a reassuring safety profile for its use. In contrast, LE cream displayed reversible toxicity from drug molecule itself in animals at the given dose, dissipating after 3 weeks of withdrawal and recovery. This study establishes a solid foundation for the safe clinical use of third-generation aromatase inhibitors. It highlights transdermal creams as a promising drug delivery carrier for administering them.

Quantification and sensitivity assessment of Chinese provincial ecological compensation in the perspective of carbon deficit redistribution

The ecological compensation mechanism is a tool for managing regional development and promoting the green economy. This paper proposes a revised model for carbon emissions and absorption based on IPCC, then analyses the spatial and temporal variations of carbon emissions, absorption, and deficit in 31 provinces of China from 2001 to 2019. A model was developed to redistribute carbon deficits and compensate for ecological imbalances, with the aim of eliminating background differences between regions. The concept of ecological compensation sensitivity was proposed, and a redundancy analysis (RDA) was conducted to detect possible influencing factors. Results indicate that: (1) The carbon deficits were relatively substantial in the centre and developed coastal regions, which were the subject regions of China’s ecological compensation. Meanwhile, the northwest and southwest regions were the object regions of ecological compensation, and the compensated object regions tended to extend towards the southeast. The majority of compensated subject areas are generally less sensitive than compensated object regions. (2) The graph of carbon deficit volume over time shows that China’s two carbon targets are closely aligned. The distribution of China’s ecological compensation amounts follows the pattern of provincial economic development levels, with higher compensation amounts concentrated in the central and coastal regions. There is a positive correlation between GDP, year, and population size with carbon emission and carbon deficit. Additionally, there is a positive correlation between year, region, and carbon absorption. (3) This compensation model can strongly incentivise the compensation subject area to proactively adjust its economic development model to cope with the significant compensation pressure. Additionally, it can fully encourage the compensation recipient area to continue adhering to the green economic development model. The conclusions of the study hold significant reference value for promoting the development of a green, low-carbon economy.

High-power fiber laser incident beam absorptivity variation of molten pool surfaces during their solid-liquid-gas state evolution

The thermal and ablation effects of lasers are widely used in laser additive manufacturing, laser welding, laser cleaning, and laser cladding technologies. Absorptivity is the core index of laser beam-thermal energy conversion efficiency. This paper analyzed the irradiated material's absorption behavior during the solid-liquid-gas evolution of laser-ablated metal surfaces by comparing the temperature fields and the corresponding weld cross-sections for different laser action periods, considering the fusion and vaporization latent heats. The solid-liquid-gas state evolution of high-power fiber laser-irradiated metal surfaces occurs during several milliseconds, with a short solid-phase existence period, since fusion or melting time is much shorter than the vaporization time. As the solid-liquid-gas state evolves, the average absorptivity and the share of thermal conduction energy loss decrease with the laser action time, while the fusion energy loss gradually increases. The solid-phase surface of the metal in laser processing absorbs significantly more incident laser energy than the liquid-phase one. The longer the solid-phase occurrence period of the metal surface during the laser action, the greater its average absorptivity of the incident laser. By increasing the laser spot area and scanning rate, the solid-phase period of the laser-irradiated metal surface can be increased, improving its incident laser absorptivity.

Shifting shapes: Density variations and physicochemical characteristics from spheres to rods

This work extensively explores purifying cetyltrimethylammonium bromide (CTAB)-stabilized gold nanorods, focusing on efficiently separating spheres and rods to achieve a rod-rich suspension in one cycle. Utilizing UV–vis spectroscopy and Helium ion microscopy, the study delves into nanorods' spectral traits across different aspect ratios (AR 3–6). Results show centrifugation greatly influences gold nanorods' spectral features, indicating a link between CTAB-coated nanorod density and absorbance levels post-centrifugation. This quantitative evaluation enhances understanding of purification dynamics, highlighting effects on purity and density while offering insights for future refinements. Emphasizing centrifugation's role in reducing byproducts, nanoparticle density changes, and absorbance variations, the study's consistent spectral profiles affirm the effectiveness of purification parameters for stability and nanoparticle density maintenance. By quantitatively analyzing centrifugation duration's impact on spectral properties and shape separation dynamics, the research provides an empirical foundation for optimizing gold nanorod suspension purification processes. Additionally, a clear correlation between AR and absorbance-to-density ratios pre- and post-centrifugation underscores AR's relevance in comprehending nanorods' optical traits amidst centrifugation, benefiting purification strategies.

Phytoremediation potential of seedlings: comparing heavy metal accumulation in Ailanthus, Acer, and Fraxinus species.

This study investigates the phytoremediation potential of non-productive seedlings of Ailanthus altissima, Acer pseudoplatanus, and Fraxinus excelsior for lead, cadmium, and zinc accumulation in contaminated soils of Zanjan Province, an industrial area with significant pollution. The evaluation employed a completely randomized design, with three treatment levels for each element, alongside a control treatment, replicated three times over a two-year period. A total of 810 one-year-old seedlings from the three species were involved in the study. Soil contamination levels, ranging from 0 to 2000mg/kg for lead and zinc and from 0 to 200mg/kg for cadmium, were administered through soil pot irrigation. Sampling of seedling stems and pot soils was conducted in November of 2021 and 2022. The absorption levels of elements in the samples were determined using the dry acid digestion method and an ICP-OES atomic absorption spectrometer. Results indicate species-specific variations in metal absorption, with Ailanthus showing the highest accumulation rates. Findings suggest Ailanthus as a promising candidate for soil improvement in polluted environments, particularly in contaminated soils of Zanjan Province.

WIDEBAND ABSORBANCE PATTERNS IN ADULTS WITH CENTRAL AND MARGINAL TYMPANIC MEMBRANE PERFORATION

IntroductionThis study aimed to investigate the impact of central and marginal tympanic membrane perforations (TMP) on wideband absorbance (WBA) and compare it with normal ears.Material and methodsThree groups of individuals, aged 18 to 50 years: Group I with central TMP (<i>n</i> = 65), Group II with marginal TMP (<i>n</i> = 13), and Group III with normal middle ears (<i>n</i> = 20) were considered. WBA measurements were performed at peak and ambient pressure conditions across frequencies.ResultsSignificant differences in WBA were observed between the groups with central and marginal TMP and the normal ear group across all frequencies. Central TMP exhibited decreased absorbance at low frequencies and increased absorbance at high frequencies, peaking at 5000 Hz. Marginal TMP showed peaks at 600, 4000, and 6000 Hz with decreased absorbance at 2000 Hz. Central TMP exhibited lower absorbance than marginal TMP at lower frequencies, while marginal TMP showed decreased absorbance at mid and high frequencies.ConclusionsThese findings highlight the role of WBA in differentiating normal ears from those with TMP. Understanding TM vibration patterns and frequency-dependent variations in absorbance enhances diagnostic accuracy and clinical management.

Delicate Regulation of Central Substituents Boosts Organic Photovoltaic Performance of Dimeric Acceptors.

Dimeric acceptors are expected to satisfy both excellent power conversion efficiency (PCE) and operational stability of organic solar cells (OSCs). However, comparing to highly planar and symmetrical monomer-like acceptors, the quite different steric/spatial configurations of dimeric acceptors affect device outcomes greatly. Herein, on basis of the same dimeric molecular platform that constructed by bridging central units of two monomer-like acceptor, diverse substituents (─OCH3 for D1, ─CH3 for D2, and ─CF3 for D3) are grafted on central units to regulate the three dimensions (3D) geometries of dimeric acceptors delicately. A systematic investigation reveals the substituent-dependent variation of energy level, absorption, and molecular packing behavior. Consequently, D2 acceptor, characteristic of more favorable configuration, affords a superior film morphology and charge transfer/transport dynamics in resulting OSCs, thus yielding an excellent PCE of 17.50% along with a good long-term stability. This work manifests the crucially important role of central substituents in constructing high-performance dimeric acceptors.

A nondestructive technique for the sex identification of third instar Cochliomyia macellaria larvae.

Forensic entomology plays an important role in medicolegal investigations by using insects, primarily flies, to estimate the time of colonization. This estimation relies on the development of the flies found at the (death) scene and can be affected (and sometimes corrected) by external factors, such as temperature and humidity, and internal factors, such as species and sex. This study leverages infrared (IR) spectroscopy combined with machine learning models-Partial Least Squares Discriminant Analysis (PLS-DA) and eXtreme Gradient Boosting trees Discriminant Analysis (XGBDA)-to differentiate between male and female Cochliomyia macellaria larvae, commonly found on human remains. Significant vibrational differences were detected in the infrared spectra of third instar C. macellaria larvae, with distinct peaks showing variations in relative absorbance between sexes, suggesting differences in biochemical compositions such as cuticular proteins and lipids. The application of PLS-DA and XGBDA yielded high classification accuracies of about 94% and 96%, respectively, with female spectra consistently having higher sensitivity than males. This non-destructive approach offers the potential to refine supplemental post-mortem interval estimations significantly, enhancing the accuracy of forensic analyses.