Low SO2 Research Articles

Blood‐based biomarkers as early predictor of mortality in experimental hemorrhagic shock

BackgroundHemorrhagic shock remains a major cause of mortality and morbidity on the battle field. Appropriate use of blood‐based biomarkers is clinically important to manage patients and predict death versus survival in the early stage of hemorrhagic shock. In continuation of our previous study, blood‐based early biomarkers were tested in 94 rats undergoing hemorrhagic shock.MethodsSprague Dawley rats (both genders) were anesthetized with either intraperitoneal ketamine and xylazine or with Isoflurane. Rats were intubated and ventilated with room air. After heparinization, hemorrhagic shock was induced by withdrawing blood to a fixed mean blood pressure of 30 or 40 mmHg for 30 minutes, 35 minutes, 45 minutes, or 60 minutes and then the shed blood was reinfused. Arterial blood samples were collected 1–3 hours after resuscitation with shed blood. The rats were allowed to survive for 6 weeks.ResultsThe pH, bicarbonate (HCO3), oxygen saturation (SO2%), base excess and calcium levels were significantly lower in rats that died (n=63) versus survivors (n=31). Rats that died had significantly elevated anion gap, potassium, sodium and chloride levels compared to rats that survived (Table). PO2, PCO2, hematocrit, hemoglobin, glucose and lactate levels are comparable between rats that died versus survived.ConclusionsThe low pH, HCO3, SO2%, base excess and calcium coupled with high anion gap and high potassium, sodium and chloride levels may help predict long term prognosis in hemorrhagic shock.Support or Funding InformationThis work was supported by the Office of the Assistant Secretary of Defense for Health Affairs, through the Peer Reviewed Medical Research Program under Award NO. W81XWH‐16‐1‐0606. Opinions, interpretations, conclusions and recommendations are those of the author and are not necessarily endorsed by Department of Defense.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

The pilot demonstration of a honeycomb catalyst for the DeNOx of low-temperature flue gas from an industrial coking plant

The practical low-temperature DeNOx catalyst has a huge market demand for the flue gas purification of the widespread small-scale boilers. In this work, the modified V-based low-temperature honeycomb catalyst was produced through the hydrothermal process of metatitanic acid, which exhibited high strength and low SO2 oxidation rate. The pilot test of flue gas from a coking plant demonstrated that the honeycomb catalyst could endure the high content of SOx (400–600 ppm) and H2O (>15 vol%) in flue gas at 300 °C and work stably with adjustable NO removal efficiency and little ammonia slip. After dry desulphurization and dedusting processes, the catalytic activity could still keep stable during the three-week test at as low as 220 °C, and the catalyst showed none deactivation. But the obvious deactivation of catalyst was observed at 270 °C before dry desulphurization and dedusting processes. The characterization of spent catalyst revealed that the deactivation of catalyst mainly resulted from the covering of catalytic surface by ammonium sulfate and ferric sulfate species, which formed through the gas reaction of inherent SO3 with NH3 for ammonium sulfate species and the corrosion/stripping of Fe based pipe for ferric sulfate species, respectively. After the re-calcination process, the deactivated catalyst could be regenerated with the decomposition of sulfate species.

Ethanol stress in Oenococcus oeni: transcriptional response and complex physiological mechanisms.

Oenococcus oeni is the dominant species able to cope with a hostile environment of wines, comprising cumulative effects of low pH, high ethanol and SO2 content, nonoptimal growth temperatures and growth inhibitory compounds. Ethanol tolerance is a crucial feature for the activity of O. oeni cells in wine because ethanol acts as a disordering agent of its cell membrane and negatively affects metabolic activity; it damages the membrane integrity, decreases cell viability and, as other stress conditions, delays the start of malolactic fermentation with a consequent alteration of wine quality. The cell wall, cytoplasmic membrane and metabolic pathways are the main sites involved in physiological changes aimed to ensure an adequate adaptive response to ethanol stress and to face the oxidative damage caused by increasing production of reactive oxygen species. Improving our understanding of the cellular impact of ethanol toxicity and how the cell responds to ethanol stress can facilitate the development of strategies to enhance microbial ethanol tolerance; this allows to perform a multidisciplinary endeavour requiring not only an ecological study of the spontaneous process but also the characterization of useful technological and physiological features of the predominant strains in order to select those with the highest potential for industrial applications.

Two milligrams IV hydromorphone is efficacious for treating pain but is associated with oxygen desaturation

To evaluate the safety and efficacy of a single dose of 2 mg i.v. hydromorphone administered to emergency department patients in acute severe pain. Prospective interventional. Urban academic emergency department. PATIENT, PARTICIPANTS: Nonelderly adults (21- 64-years-old) with acute severe pain and baseline oxygen saturation (SO2) > or = 95 percent. Two milligrams i.v. hydromorphone administered over 2-3 minutes. The primary outcome was use of naloxone as a reversal agent. Secondary outcomes included degree of pain relief as measured on a numerical rating scale, frequency of oxygen desaturation (SO2 < 95 percent), and side effects. Of the 269 patients, none received i.v. naloxone. Median pain scores fell from 10 (worst pain possible) at baseline to 1 within 5 minutes and to 0 (no pain) at 30 minutes. SO2 was > or = 95 percent at all time points in 68 percent of patients (95 percent CI 62-73 percent), while 26 percent (95 percent CI 21-32 percent) had one or more SO2 levels between 90-94 percent, and 6 percent (95 percent CI 4-10 percent) had SO2 values below 90 percent at one or more time points. The lowest SO2 was 82 percent. The incidence of nausea and vomiting were 16 percent and 7 percent, respectively. Two milligrams i.v. hydromorphone provides efficacious and rapid pain relief in nonelderly adults presenting to the ED with acute severe pain. However, oxygen desaturation below 95 percent occurred in about one third of patients. Although no noticeable clinical signs of hypoxemia occurred, a conservative interpretation of this finding suggests that 2 mg i.v. hydromorphone is too much opioid to be given routinely to patients in pain as a single initial dose.

Calibration and assessment of electrochemical air quality sensors by co-location with regulatory-grade instruments

Abstract. The use of low-cost air quality sensors for air pollution research has outpaced our understanding of their capabilities and limitations under real-world conditions, and there is thus a critical need for understanding and optimizing the performance of such sensors in the field. Here we describe the deployment, calibration, and evaluation of electrochemical sensors on the island of Hawai`i, which is an ideal test bed for characterizing such sensors due to its large and variable sulfur dioxide (SO2) levels and lack of other co-pollutants. Nine custom-built SO2 sensors were co-located with two Hawaii Department of Health Air Quality stations over the course of 5 months, enabling comparison of sensor output with regulatory-grade instruments under a range of realistic environmental conditions. Calibration using a nonparametric algorithm (k nearest neighbors) was found to have excellent performance (RMSE &lt; 7 ppb, MAE &lt; 4 ppb, r2 &gt; 0.997) across a wide dynamic range in SO2 (&lt; 1 ppb, &gt; 2 ppm). However, since nonparametric algorithms generally cannot extrapolate to conditions beyond those outside the training set, we introduce a new hybrid linear–nonparametric algorithm, enabling accurate measurements even when pollutant levels are higher than encountered during calibration. We find no significant change in instrument sensitivity toward SO2 after 18 weeks and demonstrate that calibration accuracy remains high when a sensor is calibrated at one location and then moved to another. The performance of electrochemical SO2 sensors is also strong at lower SO2 mixing ratios (&lt; 25 ppb), for which they exhibit an error of less than 2.5 ppb. While some specific results of this study (calibration accuracy, performance of the various algorithms, etc.) may differ for measurements of other pollutant species in other areas (e.g., polluted urban regions), the calibration and validation approaches described here should be widely applicable to a range of pollutants, sensors, and environments.

Characteristics of inorganic aerosol formation over ammonia-poor and ammonia-rich areas in the Pearl River Delta region, China

A well-evaluated Comprehensive Air quality Model with extensions (CAMx) was used to simulate concentrations of secondary inorganic aerosols in fine particulate matter (PM2.5) over Pearl River Delta (PRD) region during two separate months (April and October) in 2013. An indicator of adjusted gas ratio (AdjGR) was used to characterize PM chemistry under both NH3-poor (NP) and NH3-rich (NR) conditions as well as to identify their respective spatiotemporal patterns at different PM2.5 levels. The results were as follows: (1) Based on both observed molar ratio of [NH4+]/[SO42−] and modeled AdjGR, NR and NP conditions exhibited diurnal, daily, and seasonal variations. (2) A larger area in PRD had NP conditions over the two months when pollution was apparent; this NP region tended to occur downwind of PRD in October and the central region of PRD in April, with high PM2.5 concentrations in both. (3) This wider NP distribution could be related to higher nitrogen oxidation ratio (NOR), with more NOx converting to nitrate. Under conditions of higher pollution, there were relative lower degree of sulfate neutralization (DSN) and particle neutralization ratio (PNR). This supports the claim that NH3 may not be fully neutralized by SO42−. (4) Modeled AdjGR displayed clear hourly variations, with the lowest levels occurring in the afternoon. Reducing NH3 emission is not as efficient as NOx at increasing evening nitrate concentrations. (5) To mitigate PM2.5 pollution even further, a greater reduction of NH3 should be suggested in chemical regions transiting to NR condition when there are lower SO2 and NOx emissions.

Numerical study of the burner parameters on the thermal field in a sulfur recovery unit thermal reactor

A sulfur recovery unit (SRU) thermal reactor is the most important equipment in a sulfur plant and is negatively affected by high temperature operations. In this paper, the effect of burner parameters, including the clearance of the acid gas tip and the inlet air swirler angle, on the thermal field in a SRU thermal reactor are investigated numerically, with the aim to reduce the high temperature inside the thermal reactor and to ensure an acceptable sulfur recovery. The simulation results show that the burner with a smaller clearance of the acid gas tip produces a lower temperature, a lower exit SO2 mole fraction and higher exit S2 and H2S mole fractions. Among the clearancs of the acid gas tip investigated, the horizontal clearance of 152.4mm and vertical clearance of 240mm yield the lowest temperature, exit SO2 mole fraction and highest exit S2, H2S mole fractions. The burner with a smaller inlet air swirler angle produces a higher temperature, a higher exit SO2 mole fraction and lower exit S2 and H2S mole fractions. Among the swirler angles investigated, 60° yields the lowest temperature, exit SO2 mole fraction and highest exit S2 , H2S mole fractions.

基于DOAS及统计量的低浓度SO2测量方法

基于DOAS及统计量的低浓度SO2测量方法

A comparative analysis of air pollutant concentrations and inflow trajectories: a case study of selected cities in South-Eastern Poland

The paper presents a comparison of air pollutant concentrations in three cities in South-Eastern Poland (Krakow, Tarnow and Rzeszow) using statistical analyses and backward trajectory modelling (the HYSPLIT model). The analyses were based on particulate matter (PM10), nitrogen dioxide (NO2) and sulphur dioxide (SO2) levels as well as meteorological data from year 2017. The performed analyses revealed, among others, that the PM10 and SO2 concentrations in the air depend on the season of the year, while the NO2 concentrations are seasonally independent, which is mainly associated with emissions from road transport. Air quality in the analysed cities depends on local meteorological conditions and the structure of emission sources, including the inflowing background. The most unfavourable situation regarding high concentrations of PM10 and NO2 occurs in Krakow. For all analysed urban background stations very similar low SO2 air concentrations are observed which proves the decreasing significance of emissions from coal combustion sources.

Comparative studies of low concentration SO2 and NO2 sorption by activated carbon supported [C2mim][Ac] and KOH sorbents

This work evaluated the ability of 1-ethyl-3-methylimidazolium acetate ionic liquid and potassium hydroxide loaded activated carbon sorbents to remove SO2 and NO2 under simulated atmospheric conditions containing ≤10 ppm of gas contaminants in air at 25 °C and relative humidity of 50%. The studies indicate the 1-ethyl-3-methylimidazolium acetate loaded activated carbon, [C2mim][Ac] sorbent, has superior sorption performance for SO2, with breakthrough times greater than pure activated carbon, pelletized KOH activated carbon and granulated KOH loaded activated carbon. The pelletized KOH loaded activated carbon had lowest performance indicating pelletized sorbents are not ideal for use in high flow rate applications such as fuel cells. The SO2 concentration significantly impacted the breakthrough times of the [C2mim][Ac] sorbent, low SO2 concentration resulted in the longest break through times but lowest sorption capacities. The granulated KOH activated carbon and pure activated carbon had highest NO2 break through times compared to [C2mim][Ac] sorbents. The simultaneous SO2 and NO2 sorption studies indicated that the [C2mim][Ac] sorbent had greater selectivity for SO2 than NO2 compared to the KOH sorbents, as evidenced by high breakthrough times for SO2 compared to NO2. Theoretical studies using DFT-B3LYP were performed to elucidate the favored binding interactions of the [C2mim][Ac] with acidic gas contaminants. Theory indicates acidic gas contaminants preferentially interact strongly with the oxygen atoms of the acetate anion compared to the imidazole cation. The computational work also confirmed experiments showing high selectivity of the 1-ethyl-3-methylimidazolium acetate ionic liquid sorbent for SO2 compared to NO2.

Gas and ash emissions associated with the 2010–present activity of Sinabung Volcano, Indonesia

Sinabung Volcano (Sumatra, Indonesia) awoke from over 1200years of dormancy with multiple phreatic explosions in 2010. After a period of quiescence, Sinabung activity resumed in 2013, producing frequent explosions, lava dome extrusion, and pyroclastic flows from dome and lava flow collapses, becoming one of the world's most active volcanoes and displacing over 20,000 citizens. This study presents a compilation of the geochemical datasets collected by the Indonesian Center for Volcanology and Geological Hazard Mitigation (CVGHM) from 2010–current (2016), which provides insights into the evolution of the eruption. Based on observations of SO2 emissions, ash componentry, ash leachate chemistry, and bulk ash geochemistry, the eruption can be split into six distinct geochemical phases. The initial stage of phreatic summit explosions (phase A) occurred from August–September 2010, during which background SO2 emissions averaged ~550±180t/d (1s.d.). An eruptive pause (phase B) starting in October 2010 abruptly ended in September 2013 with a resumption of conduit-clearing eruptions (phase C). This third phase had a relatively modest background SO2 emission rate (avg. ~430±310t/d) and produced ash consisting of accidental ejecta with high S/Cl leachate molar ratios (12.0±8.2, max 34), suggestive of deep-sourced magma and/or the incorporation of hydrothermal sulfur-bearing phases. Lava extrusion at the summit (phase D) began in mid-December 2013, and was accompanied by relatively low SO2 emission rates (360±200t/d) and lower, but variable, S/Cl leachate ratios (6.3±8.5). The most intense phase of the eruption (phase E) occurred from mid-January to late February 2014 following a major lava dome collapse. This period included increased lava extrusion rates, dozens of large eruptions per day, high SO2 emission rates (average: 1680±1070t/d, peak: ~3800t/d), and a dramatic drop in S/Cl ash leachates to ratios (average 1.4±0.5), consistent with increased degassing from shallow magma and the clearing out of sulfurous phases from the old hydrothermal system. From March 2014 through the time of writing (September 2016), Sinabung settled into a relatively steady state of lower activity (phase F). Ash emissions now consist of dominantly juvenile andesitic-dacitic material with low S/Cl leachate ratios (average 1.1±0.6). In August 2016, SO2 emissions started being measured in a continuous manner using a network of permanent scanning DOAS instruments. Background SO2 emission rates average 450±290t/d for the entirety of phase F, but have been progressively decreasing to an average of ~250–300t/d since June 2016. This long-term gradual decline in SO2 emission rates at Sinabung since early 2014 is consistent with an apparent decrease in magma supply and lava effusion rates. Our conceptual degassing model suggests that large explosions and pyroclastic flows could continue in the near-term owing to conduit plugging and dome collapses, remaining a major threat until the magma supply rate decreases further and the eruption ends.

Photooxidation of cyclohexene in the presence of SO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;: SOA yield and chemical composition

Abstract. Secondary organic aerosol (SOA) formation from a cyclohexene ∕ NOx system with various SO2 concentrations under UV light was investigated to study the effects of cyclic alkenes on the atmospheric environment in polluted urban areas. A clear decrease at first and then an increase in the SOA yield was found with increasing SO2 concentrations. The lowest SOA yield was obtained when the initial SO2 concentration was in the range of 30–40 ppb, while higher SOA yield compared to that without SO2 could not be obtained until the initial SO2 concentration was higher than 85 ppb. The decreasing SOA yield might be due to the fact that the promoting effect of acid-catalysed reactions on SOA formation was less important than the inhibiting effect of decreasing OH concentration at low initial SO2 concentrations, caused by the competition reactions of OH with SO2 and cyclohexene. The competitive reaction was an important factor for SOA yield and it should not be neglected in photooxidation reactions. The composition of organic compounds in SOA was measured using several complementary techniques including Fourier transform infrared (FTIR) spectroscopy, ion chromatography (IC), and Exactive Plus Orbitrap mass spectrometer equipped with electrospray interface (ESI). We present new evidence that organosulfates were produced from the photooxidation of cyclohexene in the presence of SO2.

Co-firing of coal and rice straw pellet in a circulating fluidized-bed reactor

This paper presents the experimental investigation of co-firing of coal with rice straw pellet in terms of combustion efficiency, gaseous emissions (CO, NOx and SO2) and occurrence of bed agglomeration. The influence of excess air ratio (EA) and mass share of rice straw in the mixed fuel were investigated in a lab-scale circulating fluidized bed (CFB) reactor. The fuel feed rate was fixed at 14 kg/hr, while the air supply was varied to achieve EA 1.28-1.94. Rice straw pellet was mixed with coal at 25% and 50% mass fraction. The results show that increasing EA generally reduced CO emission. However, at excessively high EA, CO emission started to rise due to the insufficient residence time for complete combustion and the cooling effect. The CO emission clearly reflected the combustion efficiency trend. Higher CO emission was also found when increasing biomass, which may be influenced by the lower combustion temperature and the incomplete combustion of biomass volatiles. NOx and SO2 emission strongly depended on N and S content in the fuel that is the higher rice straw addition the lower NOx and SO2. At lower EA, the observed lower NOx emission could be the effect of reduction by CO and carbon present; while the opposite effect was found at high EA. SO2 emission was more temperature dependent and continuously decreased with increasing EA. System pressure monitoring and visual observation of the spent bed showed no occurrence of bed agglomeration even at 50% addition of rice straw pellet. However, the size distribution of spent bed moved slightly towards a larger particle size range indicating a tendency of agglomeration.

Reactive Uptake of Sulfur Dioxide and Ozone on Volcanic Glass and Ash at Ambient Temperature

AbstractThe atmospheric impacts of volcanic ash from explosive eruptions are rarely considered alongside those of volcanogenic gases/aerosols. While airborne particles provide solid surfaces for chemical reactions with trace gases in the atmosphere, the reactivity of airborne ash has seldom been investigated. Here we determine the total uptake capacity (NiM) and initial uptake coefficient (γM) for sulfur dioxide (SO2) and ozone (O3) on a compositional array of volcanic ash and glass powders at ~25°C in a Knudsen flow reactor. The measured ranges of NiSO2 and γSO2 (1011–1013 molecules cm−2 and 10−3–10−2) and NiO3 and γO3 (1012–1013 molecules cm−2 and 10−3–10−2) are comparable to values reported for mineral dust. Differences in ash and glass reactivity toward SO2 and O3 may relate to varying abundances of, respectively, basic and reducing sites on these materials. The typically lower SO2 and O3 uptake on ash compared to glass likely results from prior exposure of ash surfaces to acidic and oxidizing conditions within the volcanic eruption plume/cloud. While sequential uptake experiments overall suggest that these gases do not compete for reactive surface sites, SO2 uptake forming adsorbed S(IV) species may enhance the capacity for subsequent O3 uptake via redox reaction forming adsorbed S(VI) species. Our findings imply that ash emissions may represent a hitherto neglected sink for atmospheric SO2 and O3.

The kinetics of oxygen and SO2 consumption by red wines. What do they tell about oxidation mechanisms and about changes in wine composition?

This work seeks to understand the kinetics of O2 and SO2 consumption of air-saturated red wine as a function of its chemical composition, and to describe the chemical changes suffered during the process in relation to the kinetics. Oxygen Consumption Rates (OCRs) are faster with higher copper and epigallocatechin contents and with higher absorbance at 620nm and slower with higher levels of gallic acid and catechin terminal units in tannins. Acetaldehyde Reactive Polyphenols (ARPs) may be key elements determining OCRs. It is confirmed that SO2 is poorly consumed in the first saturation. Phenylalanine, methionine and maybe, cysteine, seem to be consumed instead. A low SO2 consumption is favoured by low levels of SO2, by a low availability of free SO2 caused by a high anthocyanin/tannin ratio, and by a polyphenolic profile poor in epigallocatechin and rich in catechin-rich tannins. Wines consuming SO2 efficiently consume more epigallocatechin, prodelphinidins and procyanidins.

Global source attribution of sulfate concentration and direct and indirect radiative forcing

Abstract. The global source–receptor relationships of sulfate concentrations, and direct and indirect radiative forcing (DRF and IRF) from 16 regions/sectors for years 2010–2014 are examined in this study through utilizing a sulfur source-tagging capability implemented in the Community Earth System Model (CESM) with winds nudged to reanalysis data. Sulfate concentrations are mostly contributed by local emissions in regions with high emissions, while over regions with relatively low SO2 emissions, the near-surface sulfate concentrations are primarily attributed to non-local sources from long-range transport. Regional source efficiencies of sulfate concentrations are higher over regions with dry atmospheric conditions and less export, suggesting that lifetime of aerosols, together with regional export, is important in determining regional air quality. The simulated global total sulfate DRF is −0.42 W m−2, with −0.31 W m−2 contributed by anthropogenic sulfate and −0.11 W m−2 contributed by natural sulfate, relative to a state with no sulfur emissions. In the Southern Hemisphere tropics, dimethyl sulfide (DMS) contributes 17–84 % to the total DRF. East Asia has the largest contribution of 20–30 % over the Northern Hemisphere mid- and high latitudes. A 20 % perturbation of sulfate and its precursor emissions gives a sulfate incremental IRF of −0.44 W m−2. DMS has the largest contribution, explaining −0.23 W m−2 of the global sulfate incremental IRF. Incremental IRF over regions in the Southern Hemisphere with low background aerosols is more sensitive to emission perturbation than that over the polluted Northern Hemisphere.

Comparison of SO2 column retrievals from BRD and DOAS algorithms

Atmospheric SO2 has a significant impact on the urban environment and global climate. Band Residual Difference Algorithm (BRD) and Differential Optical Absorption Spectroscopy (DOAS) were used respectively by NASA and ESA science team to derive SO2 columns from satellite observations, but there are few studies on the comparison and validation of BRD and DOAS SO2 retrievals under the same observation conditions. In this study, the radiative transfer model SCIATRAN was firstly used to validate the accuracies of BRD and DOAS SO2 retrievals, and analyse the uncertainty of SO2 retrieval caused by band selection, O3 absorption, aerosol, surface reflectance, solar and viewing zenith angle. Finally, BRD and DOAS algorithms were applied to the same radiances from satellite observations, and comparisons of BRD and DOAS SO2 retrievals were conducted over volcanic eruption and North China. Results show that, for the case with low SO2 columns, BRD SO2 retrievals have higher retrieval accuracy than DOAS, but typical seasonal variation with high SO2 column in winter and low in summer can be more clearly discernible in DOAS SO2 retrievals than BRD from satellite observations. For the case with high SO2 columns, the differences between BRD (310.8–314.4 nm) and DOAS (315–327 nm) retrievals are large, and the value and accuracy of BRD (310.8–314.4 nm) SO2 retrievals are lower than those of DOAS (315–327 nm) retrievals. Compared with the SO2 inputs in forward model, both BRD (310.8–314.4 nm) and DOAS (315–327 nm) SO2 retrievals are underestimated for the case with high SO2 columns. The selection of wavelength range can significantly affect the accuracy of SO2 retrieval. The error of BRD SO2 retrieval from 310.8–314.4 nm is lower than other bands in the ultraviolet spectral region (306–327 nm). The increase of wavelength in the ultraviolet spectral region 306–330 nm can reduce the underestimation of DOAS SO2 retrievals in the case of high SO2 column, but slight overestimation of SO2 retrieval is found from the 315–327 nm range in the case of low SO2 column. The values of BRD and DOAS SO2 retrieval decrease with atmospheric O3 column and aerosol optical depth increasing, but increase with surface reflectance increasing. Large solar zenith angle and viewing zenith angle can introduce more errors to the BRD and DOAS SO2 retrievals. This study is important for the improvement of retrieval algorithm and the application of SO2 products from satellite observations.

The Correlation of Sulfur Distribution in LSCF and Performance Degradation under Different Operation Temperatures

The investigation on the durability of solid oxide fuel cell (SOFC) stacks in real operation environments has revealed that the cathode is contaminated with sulfur during SOFC operation, although the sulfur dioxide concentration is very low in air (in ppb level). In this work, the effect of low concentration SO2 (0.01ppm) in air on the degradation of a La0.6Sr0.4Co0.2Fe0.8O3 (LSCF6428) cathode was investigated with different operation temperature of 650 oC, 700 oC, and 800 oC for 300 h. The performance degradation of LSCF6428 cathode is most serious at 700 oC due to both of ohmic and polarization resistance increase. The sulfur distribution and the SrSO4 formation concentrate near TPB at T ≤ 700 oC, but are near cathode surface at 800 oC. These different morphology changes of cathode near TPB are the main reason for the different performance degradation of the LSCF6428 cathode at different temperature.

Image Monitoring of the Impaired Phagocytic Activity of Kupffer Cells and Liver Oxygen Saturation in a Mouse Cholangitis Model Using Contrast-Enhanced Ultrasound Imaging and Photoacoustic Imaging

Bile duct ligation (BDL) can cause cholangitis, which is known to induce impaired Kupffer cell (KC) function and increased oxygen consumption in a mouse model. It is important to monitor changes in KC function and tissue oxygen saturation, both of which are critical factors in the progression of cholangitis. The purpose of this study is to investigate the impaired phagocytic activity of KC and liver oxygen saturation (sO2) in a mouse cholangitis model using contrast-enhanced ultrasound imaging (CEUS) and photoacoustic imaging (PAI). A mouse cholangitis model was created by ligation of the common bile duct (CBDL, n = 20), and the left intrahepatic bile duct (BDL-L, n = 19), both of which were compared with the non-ligation groups—right lobe measurement group after left intrahepatic bile duct ligation (BDL-R, n = 19) and the control group (n = 14). The echogenicity and sO2 were measured by CEUS and PAI and the KC fraction was assessed at 1, 2 and 4 wk after ligation. We found a significantly lower echogenicity of the Kupffer phase in the CBDL and BDL-L groups compared with that in the control and BDL-R groups at 2 wk (p < .01). The CBDL and BDL-L groups showed a lower echogenicity than that of the BDL-R group at 4 wk (p < .01). We found a significantly lower sO2 of the CBDL and BDL-L groups compared with that of the control and BDL-R groups at 4 wk (p < .01). The CBDL and BDL-L groups showed a higher KC fraction than that of the BDL-R and control groups at each time point (p < .01). In conclusion, our study suggests that the Sonazoid CEUS and PAI could be a useful tool for monitoring impaired KC phagocytic activity and the liver hypoxic state.

Ultrahigh and Selective SO2 Uptake in Inorganic Anion-Pillared Hybrid Porous Materials.

The efficient capture of SO2 is of great significance in gas-purification processes including flue-gas desulfurization and natural-gas purification, but the design of porous materials with high adsorption capacity and selectivity of SO2 remains very challenging. Herein, the selective recognition and dense packing of SO2 clusters through multiple synergistic host-guest and guest-guest interactions by controlling the pore chemistry and size in inorganic anion (SiF62- , SIFSIX) pillared metal-organic frameworks is reported. The binding sites of anions and aromatic rings in SIFSIX materials grasp every atom of SO2 firmly via Sδ+ ···Fδ- electrostatic interactions and Oδ- ···Hδ+ dipole-dipole interactions, while the guest-guest interactions between SO2 molecules further promote gas trapping within the pore space, which is elucidated by first-principles density functional theory calculations and powder X-ray diffraction experiments. These interactions afford new benchmarks for the highly efficient removal of SO2 from other gases, even if at a very low SO2 concentration. Exceptionally high SO2 capacity of 11.01 mmol g-1 is achieved at atmosphere pressure by SIFSIX-1-Cu, and unprecedented low-pressure SO2 capacity is obtained in SIFSIX-2-Cu-i (4.16 mmol g-1 SO2 at 0.01 bar and 2.31 mmol g-1 at 0.002 bar). More importantly, record SO2 /CO2 selectivity (86-89) and excellent SO2 /N2 selectivity (1285-3145) are also achieved. Experimental breakthrough curves further demonstrate the excellent performance of these hybrid porous materials in removing low-concentration SO2 .