Emission Ratio Research Articles

Use of FRET-Sensor 'Mermaid' to Detect Subtle Changes in Membrane Potential of Primary Mouse PASMCs.

Subtle changes in the membrane potential of pulmonary arterial smooth muscle cells (PASMCs) are pivotal for controlling pulmonary vascular tone, e.g., for initiating Hypoxic Pulmonary Vasoconstriction, a vital mechanism of the pulmonary circulation. In our study, we evaluated the ability of the fluorescence resonance energy transfer (FRET)-based voltage-sensor Mermaid to detect such subtle changes in membrane potential. Mouse PASMCs were isolated and transduced with Mermaid-encoding lentiviral vectors before the acceptor/donor emission ratio was assessed via live cell FRET-imaging. Mermaid's sensitivity was tested by applying specific potassium chloride (KCl) concentrations. These KCl concentrations were previously validated by patch clamp recordings to induce depolarization with predefined amplitudes that physiologically occur in PASMCs. Mermaid's emission ratio dose-dependently increased upon depolarization with KCl. However, Mermaid formed unspecific intracellular aggregates, which limited the usefulness of this voltage sensor. When analyzing the membrane rim only to circumvent these unspecific signals, Mermaid was not suitable to resolve subtle changes in the membrane potential of ≤10 mV. In summary, we found Mermaid to be a suitable alternative for reliably detecting qualitative membrane voltage changes of more than 10 mV in primary mouse PASMCs. However, one should be aware of the limitations associated with this voltage sensor.

Enhanced trion emission from WS2 monolayers directly exfoliated on Ag nanohole arrays

The extraordinarily large exciton binding energies of transition metal dichalcogenides (TMDs) have attracted significant attention in both fundamental scientific research and innovative technology development. TMD-metal nanostructures have been fabricated to control excitonic behaviors as well as improve the light-matter interaction in TMDs. WS2 monolayers are integrated with periodic Ag nanohole (AgNH) arrays prepared using a template stripping method. The ultrasmooth and contamination-free surface of the template-stripped Ag layer allows for the direct exfoliation of WS2 flakes on the AgNHs. Surface plasmon excitation increases optical absorption in WS2/AgNH, as evidenced by reflectance, PL, and Raman measurements, along with numerical calculations. Furthermore, the AgNH structures significantly increase the trion-to-exciton emission ratios from the WS2 monolayers on them. Nanoscopic surface photovoltage mapping of WS2/AgNH using Kelvin probe force microscopy can visualize electron accumulation at the suspended WS2 region under light illumination, which triggers the formation of trions. All the results highlight the capability of WS2/AgNH to boost trion emission through plasmon-induced concentrated light and a built-in potential gradient. This work introduces a simple and efficient strategy for fabricating TMD-metal integrated systems to control their excitonic behaviors.

Comparing levoglucosan and mannosan ratios in sediments and corresponding aerosols from recent Australian fires

The monosaccharide anhydrides levoglucosan, mannosan, and galactosan are known as ‘fire sugars’ as they are powerful proxies used to trace fire events. Despite their increasing use, their application is not completely understood, especially in the context of tracing past fire events using sediment samples. There are many uncertainties about fire sugar formation, partitioning, transport, complexation, and stability along all stages of the source-to-sink pathway. While these uncertainties exist, the efficacy of fire sugars as fire tracers remains limited. This study compared high-resolution fire sugar fluxes in freshwater sediment cores to known fire records in Tasmania, Australia. Past fire events correlated with fire sugar flux increases down-core, with the magnitude of the flux inversely proportional to the distance of the fires from the study site. For the first time, fire sugar ratios (levoglucosan/mannosan, L/M) in aerosols were compared with those in sediments from the same time-period. The L/M ratio in surface sediments (1.42–2.58) were significantly lower than in corresponding aerosols (5.08–15.62). We propose two hypotheses that may explain the lower average L/M of sediments. Firstly, the degradation rate of levoglucosan is higher than mannosan in the water column, sediment-water interface, and/or sediment. Secondly, the L/M ratio of non-atmospheric emissions during fires may be lower than that of atmospheric emissions from the same fire. Due to the uncertainties about transport partitioning (atmospheric versus non-atmospheric emissions) and fire sugar degradation along all stages of the source-to-sink pathway, we advise caution when inferring vegetation type (e.g. softwood, hardwood, or grasses) based purely on fire sugar ratios in sediments (e.g. L/M ratio). Future investigations are required to increase the efficacy of fire sugars as a complimentary, or standalone, fire tracer in sediments.

Enhancement of Excimer Formation Ability by Modulating the Length of Side-Chains in Polyhedral Oligomeric Silsesquioxane (POSS) and Application for Fluorescence Sensors for Metal Cations

Abstract Polyhedral oligomeric silsesquioxane (POSS) is a molecule with an inorganic cubic structure and organic side-chains and has attracted great attention for its application to luminescent materials by modifying luminophores. In this study, pyrenes-integrated POSSs with various lengths of side-chains were synthesized and the effect of the length on luminescent properties was evaluated. In optical measurements, highly efficient excimer emission was observed under dilute solution conditions. The higher value of the intensity ratio of the excimer emission to the monomer one was detected in the shortest side-chains. It is likely that the shorter side-chains of POSS lead to more efficient intramolecular interaction. Interestingly, we also found that the luminescence color was changed in response to metal cations in the dilute solutions. From the mechanistic study, metal cations such as Cu2+ can accelerate hydrolysis at the linker moiety. As a result, highly-sensitive luminescent sensors were obtained. These data represent that POSS can work as a reaction field where chemical reactions are accelerated through the accumulation of reactive species.

In situ monitoring of polymeric patchy micelles upon non-covalent post-assembly modification

ABSTRACT Polymeric patchy micelles (PPMs) are nanostructures with distinct regions on their surfaces, offering unique properties for various applications. Herein, we present a straightforward method for monitoring the structure of PPMs formed via non-covalent post-assembly modification (NCPAM). By employing 1-pyrenemethylamine, a pyrene-based molecule, as both a modifier and fluorescent probe, we demonstrate that the formation of PPMs with a higher order aggregation state of pyrene induces a stronger pyrene excimer emission. This leads to variations in the excimer-to-monomer emission ratio, serving as a parameter for studying structural changes in PPMs during NCPAM. In situ monitoring of PPM formation and temperature-dependent transformations is achieved using fluorescent analytical method, providing valuable insights into their structural evolution and dynamic behaviour. This study offers a straightforward approach to understanding and controlling PPM structures, facilitating the design of advanced nanomaterials for diverse applications.

Upconversion Emission and Dual-Mode Sensing Characteristics of NaYF4:Yb3+/Er3+ Microcrystals at High and Ultralow Temperatures.

In this study, we investigate micrometer-sized NaYF4 crystals double-doped with Yb3+/Er3+ lanthanide ions, designed for temperature-sensing applications. In contrast to previous studies, which focused predominantly on the high-temperature regime, our investigation spans a comprehensive range of both high and ultralow temperatures. We explore the relationship between temperature and the upconversion luminescence (UCL) spectra in both frequency and time domains. Our findings highlight the strong dependence of these spectral characteristics of lanthanide-doped NaYF4 crystals on temperature. Furthermore, we introduce a dual-mode luminescence temperature measurement technique, leveraging the upconversion emission intensity ratio for both green and red emissions. This study also examines the correlation between temperature sensing, energy level disparities, and thermal coupling in Er3+ ions across various temperature scales. Our research contributes to advancing the understanding and application of lanthanide-doped materials, setting a foundation for future innovations in temperature sensing across diverse fields.

Experimental Demonstration of a Large Transverse Emittance Ratio 11∶1 in the Relativistic Heavy Ion Collider for the Electron-Ion Collider.

The Electron-Ion Collider (EIC), to be constructed at Brookhaven National Laboratory, will collide polarized high-energy electron beams with hadron beams, achieving luminosities of up to 1.0×10^{34} cm^{-2} s^{-1} in the center-of-mass energy range of 20-140GeV. To achieve such high luminosity, the EIC will employ small and flat beams at the interaction point. In the hadron storage ring of the EIC, the ratio of horizontal to vertical emittances is approximately 11∶1. In contrast, in previous or existing hadron colliders, the horizontal and vertical emittances are typically similar or closely matched. At the Relativistic Heavy Ion Collider (RHIC), we experimentally demonstrated a large transverse emittance ratio of 11∶1 with gold ion beams at a particle energy of 100GeV per nucleon, thanks to stochastic cooling and fine decoupling. Furthermore, we demonstrated collisions with flat beams, featuring a transverse beam size ratio of 3∶1 for the first time at the RHIC.

Research on coupling optimization of carbon emissions and carbon leakage in international construction projects

Due to the rapid economic development of globalization and the intensification of economic and trade exchanges, cross-international and regional carbon emissions have become increasingly severe. Governments worldwide establish laws and regulations to protect their countries' environmental impact. Therefore, selecting robustness evaluation models and metrics is an urgent research topic. This article proves the reliability and scientific of the assessment data through literature coupling evaluation, multidisciplinary coupling mathematical model and international engineering case analysis. The innovation of this project's research lies in the comprehensive analysis of the complex coupling effects of various discrete data and uncertainty indicators on the research model across international projects and how to model and evaluate interactive effects accurately. This article provides scientific measurement standards and data support for governments worldwide to formulate carbon tariffs and carbon emission policies. Case analysis data shows that the carbon emission ratio of exporting and importing countries is 0.577:100; the carbon trading quota ratio is 32.50:100.

Concentrations of Volatile Methyl Siloxanes in New York City Reflect Emissions from Personal Care and Industrial Use.

Volatile methyl siloxanes (VMS) are a group of organosilicon compounds of interest because of their potential health effects, their ability to form secondary organic aerosols, and their use as tracer compounds. VMS are emitted in the gas-phase from using consumer and personal care products, including deodorants, lotions, and hair conditioners. Because of this emission route, airborne concentrations are expected to increase with population density, although there are few studies in large urban centers. Here, we report summertime concentrations and daily variations of VMS congeners measured in New York City. Median concentrations of the 6 studied congeners, D3 (20 ng m-3), D4 (57 ng m-3), D5 (230 ng m-3), D6 (11 ng m-3), L5 (2.5 ng m-3), and L7 (1.3 ng m-3) are among the highest reported outdoor concentrations in the literature to date. Average congener ratios of D5:D4 and D5:D6 were consistent with previously reported emissions ratios, suggesting that concentrations were dominated by local emissions. Measured concentrations agree with previously published results from a Community Multiscale Air Quality model and support commonly accepted emissions rates for D4, D5, and D6 of 32.8, 135, and 6.1 mg per capita per day. Concentrations of D4, D5, D6, L5, and L7 and total VMS were significantly lower during the day than during the night, consistent with daytime oxidation reactivity. Concentrations of D3 did not show the same diurnal trend but exhibited a strong directional dependence, suggesting that it may be emitted by industrial point sources in the area rather than personal care product use. Concentrations of all congeners had large temporal variations but showed relatively weak relationships with wind speed, temperature, and mixing height.

Quantum squeezing via self-induced transparency in a photonic crystal fiber

We study the quantum squeezing produced in self-induced transparency in a photonic crystal fiber by performing a fully quantum simulation based on the positive P representation. The amplitude squeezing depends on the area of the initial pulse: When the area is 2π, there is no energy absorption and no amplitude squeezing. However, when the area is between 2π and 3π, one observes amplitude-dependent energy absorption and a significant amount of squeezing. We also investigate the effect of damping, detuning, and temperature: The results indicate that a heightened atom-pulse coupling, caused by an increase in the spontaneous emission ratio, reduces the amplitude squeezing. Published by the American Physical Society 2024

China's Fossil Fuel CO2 Emissions Estimated Using Surface Observations of Coemitted NO2.

Accurate estimates of fossil fuel CO2 (FFCO2) emissions are of great importance for climate prediction and mitigation regulations but remain a significant challenge for accounting methods relying on economic statistics and emission factors. In this study, we employed a regional data assimilation framework to assimilate in situ NO2 observations, allowing us to combine observation-constrained NOx emissions coemitted with FFCO2 and grid-specific CO2-to-NOx emission ratios to infer the daily FFCO2 emissions over China. The estimated national total for 2016 was 11.4 PgCO2·yr-1, with an uncertainty (1σ) of 1.5 PgCO2·yr-1 that accounted for errors associated with atmospheric transport, inversion framework parameters, and CO2-to-NOx emission ratios. Our findings indicated that widely used "bottom-up" emission inventories generally ignore numerous activity level statistics of FFCO2 related to energy industries and power plants in western China, whereas the inventories are significantly overestimated in developed regions and key urban areas owing to exaggerated emission factors and inexact spatial disaggregation. The optimized FFCO2 estimate exhibited more distinct seasonality with a significant increase in emissions in winter. These findings advance our understanding of the spatiotemporal regime of FFCO2 emissions in China.

Modeling Circumstellar Gas Emission around a White Dwarf Using cloudy

The chemical composition of an extrasolar planet is fundamental to its formation, evolution, and habitability. In this study, we explore a new way to measure the chemical composition of the building blocks of extrasolar planets by measuring the gas composition of the disrupted planetesimals around white dwarf stars. As a first attempt, we used the photoionization code Cloudy to model the circumstellar gas emission around white dwarf Gaia J0611−6931 under some simplified assumptions. We found that most of the emission lines are saturated, and the line ratios approach the ratios of thermal emission; therefore, only lower limits to the number density can be derived. Silicon is the best-constrained element in the circumstellar gas, and we derived a lower limit of 1010.3 cm−3. In addition, we placed a lower limit on the total amount of gas to be 1.8 × 1019 g. Further study is needed to better constrain the parameters of the gas disk and connect it to other white dwarfs with circumstellar gas absorption.

Seoul National University's Energy Consumption and Greenhouse Gas Emissions Characteristics in Preparation for the 2050 Carbon Neutrality Transition and the 2030 NDC

In this study, the characteristics of energy consumption and greenhouse gas emissions at Seoul National University (SNU) were presented, and Energy·Greenhouse Gas Balance Model of University Campus was proposed based on this analysis. Additionally, the conditions and features required to achieve SNU's 2030 National Determined Contribution (NDC) goals in the building sector and aim for a carbon-neutral campus by 2050 were examined. The Energy·Greenhouse Gas Balance Model of University Campus is expected to be beneficial for preparing nationwide universities for the transition to carbon-neutral campuses. As of 2021, SNU emitted approximately 141 kilotons of CO<sub>2eq.</sub>, with a greenhouse gas emission ratio of around 8:2 for electricity and gas usage. The total energy consumption at SNU was 809 GWh (69,600 TOE), considering conversion losses, and the electricity usage was 659 GWh. The actual energy consumption on the SNU campus included 247 GWh of electricity and 151 GWh of gas and petroleum usage. Energy consumption in SNU, particularly in engineering and science research facilities, accounted for 46% of the overall energy consumption, emphasizing the need for greenhouse gas reduction through understanding the energy usage characteristics of these facilities. To achieve SNU's goals of reaching the 2030 NDC building sector targets and a carbon-neutral campus by 2050, it is crucial not only to enhance overall energy efficiency and manage total energy consumption but also to decarbonize the electricity used at SNU.

Heavy-Atom Effect Regulating Room-Temperature Phosphorescence of Organic-Inorganic Zn-Based Halides for White-Light Emission.

Organic-inorganic metal halides (OIMHs) with room-temperature phosphorescence (RTP) properties have aroused great research enthusiasm as outstanding broadband white-light emitters. Current studies on OIMHs with white-light emission were achieved via self-trapped excitons (STEs), but the unclear mechanism of STE formation is not favorable for the design of materials. In this work, zero-dimensional OIMHs composed of organic 3,4,5-trimethoxybenzylamine (TBA) and zine halide were synthesized, which enhanced the ratio of the RTP emission to the fluorescence emission from the TBA ligand. The experimental and mechanistic analyses demonstrate that the manageable RTP is mainly caused by the heavy-atom effect. In particular, by adjusting the incorporation ratio of halogen, an obvious white-light emission with a chromaticity coordinate value of (0.31, 0.33) can be achieved. This work developed a method for regulating the RTP of OIMHs with the heavy-atom effect to realize white-light emission, providing a new idea for the design of white-light emission materials.

A comprehensive X-ray analysis of the massive O-type binary HD 93250 over two decades

Massive star winds are known to be responsible for X-ray emission arising from wind plasma heated by the strong shocks up to temperatures of 10$^6$--10$^7$ K in the case of colliding wind binaries. The investigation of X-ray emission from massive stars thus constitutes a valuable tool for identifying binaries, which is otherwise a difficult task using classical techniques. We investigated thermal and nonthermal X-ray emission from the massive O-type star HD\,93250 to unveil its binary orbital parameters independently. To meet our goal, we analyzed X-ray data obtained with European Photon Imaging Camera on board XMM-Newton spanning over sim 19 years. Additionally, we analyzed NuSTAR observations of HD\,93250 taken at various epochs. We determine the variability timescale of the X-ray emission to be 193.8pm 1.3\,d, in full agreement with the 194.3pm 0.4\,d period derived from the astrometric orbit. The X-ray spectrum of HD\,93250 is well explained by a three-temperature thermal plasma emission model with temperatures of 0.26, 1.0, and 3.3 keV. The resulting X-ray flux varies in compliance with the typical colliding wind emission from eccentric massive binaries where it enhances near periastron passage and decreases gradually close to apastron in proportion to the inverse of the binary separation. The periastron-to-apastron X-ray emission ratio points to an eccentricity range of 0.20-0.25, once again in agreement with the previously determined astrometric orbit. Finally, we do not detect any hard X-ray emission attributable to nonthermal emission above 10 keV. Given the derived plasma temperature, the strong phase-locked variability, and the significant over-luminosity in X-rays, we establish that the X-ray emission from HD\,93250 is dominated by the colliding-wind region. Our results lend support to the idea that X-ray time analysis of massive stars constitutes a relevant tool for investigating their multiplicity and for extracting relevant information on their basic orbital parameters ---such as period and eccentricity--- independently of any orbital solution derived from classical techniques.

Comparative environmental analysis of sugar beet production using a solar-driven robot and conventional systems from a sustainability perspective

In the context of rapid global population growth and climate change, balancing agricultural productivity with environmental sustainability has never been more important. Precision farming technologies, including robotics, are touted as having huge potential to increase farm productivity, reduce energy and resource use and compact soil, while reducing the overall environmental impact of on-farm production. This comprehensive study presents, for the first time, a detailed analysis and environmental benchmarking of two organic sugar beet production (SBP) systems, conventional (CONV) and robotic (RBT), based on field experiments in Lithuanian conditions where a solar-powered robot is integrated into the production system to carry out sowing and weeding operations. In order to reduce the potential environmental impact and to understand the consequences of using the robot in agriculture, a Life Cycle Assessment (LCA) of the entire SBP process up to the factory gate was carried out. The results of the analysis show that the conventional system has higher total GHG emissions than the robotic system, 36.98 and 27.18 kg CO2eq t−1, respectively, with poultry manure being the largest contributor. The higher beet yield in the RBT system, mainly due to effective weed control, resulted in a higher GHG emissions ratio (14.72) and a higher sustainability index (13.72). The LCA results showed that the CONV system had a higher negative environmental impact than the RBT in all eleven environmental impact categories assessed, with the most pronounced difference in the Ozone Depletion (OD) category. Diesel fuel was identified as the most important environmental factor for organically growing sugar beet in all considered impact categories, with the most notable environmental impact (about 94%) in the terrestrial ecotoxicity category in both systems. Normalization of the results showed that marine aquatic ecotoxicity (ME) had the greatest (78%) influence of all exposure categories for both cultivation systems, CONV – 22079.82, and RBT 18121.61 kg 1.4-DBeq per ton of produced sugar beet. The study found that increasing yields and reducing fossil fuel use in organic farming are the two most promising strategies for achieving sustainability and efficiency in food production.

Volcanic soil gas 4He/CO2 ratio: a useful geochemical tool for real-time eruption forecasting

At many dormant volcanoes, magmatic gases are not channeled through preferential degassing routes as fumaroles and only percolate through the flanks of the volcano in a diffuse way. This type of volcanic gas emission provides valuable information, even though the soil matrix contains an important atmospheric component. This study aimed to demonstrate that chemical ratios such as He/CO2 in soil gases provide excellent information on the evolution of volcanic unrest episodes and help forecast the volcanic eruption onset. Before and during the occurrence of the October 2011–March 2012 submarine of El Hierro, Canary Islands, more than 8500 soil He analyses and diffuse CO2 emission measurements were performed. The results show that the soil He/CO2 emission ratio began increasing drastically one month before eruption onset, reaching the maximum value 10 days before. During the eruptive period, this ratio also showed a maximum value several days before the period with the highest magma emission rate. The He/CO2 ratio was also helpful in forecasting the eruption onset. We demonstrate that this tool can be applied in real-time during volcanic emergencies. Our results also encourage a reevaluation of the global He emission from the subaerial volcanism.

Changes in Photosystem II Complex and Physiological Activities in Pea and Maize Plants in Response to Salt Stress.

Salt stress significantly impacts the functions of the photosynthetic apparatus, with varying degrees of damage to its components. Photosystem II (PSII) is more sensitive to environmental stresses, including salinity, than photosystem I (PSI). This study investigated the effects of different salinity levels (0 to 200 mM NaCl) on the PSII complex in isolated thylakoid membranes from hydroponically grown pea (Pisum sativum L.) and maize (Zea mays L.) plants treated with NaCl for 5 days. The data revealed that salt stress inhibits the photochemical activity of PSII (H2O → BQ), affecting the energy transfer between the pigment-protein complexes of PSII (as indicated by the fluorescence emission ratio F695/F685), QA reoxidation, and the function of the oxygen-evolving complex (OEC). These processes were more significantly affected in pea than in maize under salinity. Analysis of the oxygen evolution curves after flashes and continuous illumination showed a stronger influence on the PSIIα than PSIIβ centers. The inhibition of oxygen evolution was associated with an increase in misses (α), double hits (β), and blocked centers (SB) and a decrease in the rate constant of turnover of PSII reaction centers (KD). Salinity had different effects on the two pathways of QA reoxidation in maize and pea. In maize, the electron flow from QA- to plastoquinone was dominant after treatment with higher NaCl concentrations (150 mM and 200 mM), while in pea, the electron recombination on QAQB- with oxidized S2 (or S3) of the OEC was more pronounced. Analysis of the 77 K fluorescence emission spectra revealed changes in the ratio of the light-harvesting complex of PSII (LHCII) monomers and trimers to LHCII aggregates after salt treatment. There was also a decrease in pigment composition and an increase in oxidative stress markers, membrane injury index, antioxidant activity (FRAP assay), and antiradical activity (DPPH assay). These effects were more pronounced in pea than in maize after treatment with higher NaCl concentrations (150 mM-200 mM). This study provides insights into how salinity influences the processes in the donor and acceptor sides of PSII in plants with different salt sensitivity.

Carbon footprint of healthcare systems: a systematic review of evidence and methods

ObjectiveGiven the demand for net-zero healthcare, the carbon footprint (CF) of healthcare systems has attracted increasing interest in research in recent years. This systematic review investigates the results and methodological...

Near-infrared phosphorescent OLEDs exhibiting over 10% external quantum efficiency and extremely long lifetime using resonant energy transfer with a phosphorescent assist dopant

We have introduced a three-component light-emitting layer consisting of a host, a phosphorescent assist dopant, and a phosphorescent emitter to simultaneously realize high efficiency and long lifetime in NIR organic LEDs. An efficient energy transfer between the two phosphorescent materials was observed with 1 wt% doping ratio of the NIR emitter, significantly enhancing the external quantum efficiency reaching 10.5% with an emission peak at 769 nm. The device showed a low drive voltage and a long operational lifetime, with a luminance decay of less than 11% from the initial value after 4800 h under accelerated conditions of 100 mA cm−2.