Radiative impact of mixing state of black carbon aerosol in Asian outflow

The radiative impact of the mixing state of black carbon (BC) aerosol is investigated in Asian outflow. The mixing state and size distribution of BC aerosol were measured with a ground-based single-particle soot photometer at a remote island (Fukue) in Japan in spring 2007. The mass concentration of BC in Asian continental air masses reached 0.5 μg m-3, with a mass median diameter of 200-220 nm. The median value of the shell/core diameter ratio increased to ∼1.6 in Asian continental and maritime air masses with a core diameter of 200 mn, while in free tropospheric and Japanese air masses it was 1.3-1.4. On the basis of theoretical calculations using the size distribution and mixing state of BC aerosol, scattering and absorption properties of PM1 aerosols were calculated under both dry and ambient conditions, considering the hygroscopic growth of aerosols. It was estimated that internal mixing enhanced the BC absorption by a factor of 1.5-1.6 compared to external mixing. The calculated absorption coefficient was 2-3 times higher in Asian continental air masses than in clean air. Coatings reduced the single-scattering albedo (SSA) of PM1 aerosol by 0.01 -0.02, which indicates the importance of the mixing state of BC aerosol in evaluating its radiative influence. The SSA was sensitive to changes in air mass type, with a value of ∼0.98 in Asian continental air masses and ∼0.95 in Japanese and free tropospheric air masses under ambient conditions. Copyright 2008 by the American Geophysical Union

Methane emissions in Port Susan Bay: the missing link in carbon accounting

Coastal wetlands have the ability to sequester large amounts of “blue carbon” in sediments that would otherwise act as a harmful greenhouse gas in the atmosphere. The recently restored marsh in Port Susan Bay, Washington sequesters 231gC m-2 yr-1 and accretes 2.75cm of sediment per year. While this restored marsh stores nearly twice as much carbon as the nearby natural marsh, it can also emit methane, a potent greenhouse gas that has the potential to outweigh the benefits of carbon storage. It is critical to measure these emissions to determine if this site is a net source or sink of greenhouse gas potentials. The main objective of this study was to measure carbon sequestration and estimate methane emissions to complete carbon accounting in the restored area of Port Susan Bay. To calculate the most recent rate of carbon sequestration at this site, I used surface elevation table (SET) data from 2021 along with site-specific sediment characteristics and a pre-established 210Pb accretion rate correction factor. Direct, static chamber, methane measurements in the field were unsuccessful due to lack of instrument sensitivity and limited access to the lab. Estimates of methane emissions were made using proxies and published values based on environmental data. The emission estimates were then converted to carbon dioxide equivalents using a global warming potential of 25 and multiplied by the carbon fraction. Environmental data were taken alongside the direct methane measurements at four sites in the restoration area. Samples were taken approximately bimonthly during low tide from Fall 2020 through Summer 2021. I measured salinity, sulfate, redox, sediment temperature, pH, and assessed vegetation percent cover, the results of which all suggest negligible emissions. Average redox was well above -200mV year-round, the level at which methane would be produced. Salinity and sulfate (correlation R-value: 0.76) were high at all four sites in the summer months. The high salinity and sulfate suggest low methane emissions, especially in combination with the redox values. In these conditions, sulfate reduction is more energetically favorable than reduction to methane and thus suppresses emissions. While salinity and sulfate were low in the Winter (0ppt and 50ppm respectively), the low sediment temperature (below 5°C) and high redox conditions were likely not conducive to extensive, methanogenic microbial activity. Based on the environmental data, the methane emissions from this site would be between 19.37gCH4 m-2 yr-1 and 16.4 gCH4m-2yr-1. In terms of greenhouse gas equivalents, this would be between 110.7gC m-2 yr-1 and 130.75gC m-2 yr-1. The most recent estimate of carbon sequestration is nearly double the estimated emissions at 206.04gC m-2 yr-1 suggesting that this restored site is a net sink of greenhouse gas carbon equivalents. The information from this study will fill an important data gap to determine if this Pacific Northwest coastal wetland is a source or sink of greenhouse gas carbon equivalents and help inform future restoration decisions

Synthesis, Structural and Magnetic Properties of La0.5Ba0.5CoO2.75+x

Hole doping to the Co3+ ion in cobaltite perovskites can significantly modify the electromagnetic properties. We prepared the hole-doped cobaltite perovskites La0.5Ba0.5CoO2.75+x (x = 0.06 and x = 0.15). Neutron powder diffraction and dc-magnetization experiments were performed to investigate the crystal structure and magnetic properties. We found that both of the samples have the cubic crystal structure with space group Pmm in all the measured temperatures. Ferromagnetic transition occurs at 160K in x = 0.15 sample. For x = 0.06, we found the short-range ordered ferromagnetic state and a long-range ordered antiferromagnetic state coexist in low temperature

Kinetic Force Method with Quasiparticle Pairs for Numerical Modeling 3D Rarefied Gas Flows

Abstract. In the paper a new way of Kinetic Force Method application for modeling rarefied gas flows is suggested. This way is founded on a kinetic equation for auxiliary two-particle distribution function of quasiparticle pairs. One-particle distribution function satisfying the classical Boltzmann equation can be obtained from the auxiliary distribution function by a simple integration. The using of quasiparticle pairs guarantees energy and momentum conservation in the course of the rarefied gas flows modeling automatically. Comparison of the results obtained by Kinetic Force Method and DSMC method is carried out on the examples of numerical simulations of the homogeneous relaxation and the vacuum pump micro flows

Unresectable gastric cancer with gastric outlet obstruction and distant metastasis responding to intraperitoneal and folfox chemotherapy after palliative laparoscopic gastrojejunostomy: report of a case

<p>Abstract</p> <p>Background</p> <p>Gastric outlet obstruction (GOO) caused by unresectable gastric cancer is a challenging aspect of patient care. There have been no reports involving patients with obstructing gastric cancer and several incurable factors curatively treated by multimodal treatments.</p> <p>Case presentation</p> <p>We report a case of 55-year-old man who was diagnosed with a poorly differentiated adenocarcinoma in the pre-pyloric antrum with GOO by gastroscopy. An abdominal computed tomography (CT) scan revealed thickening of the gastric wall and adjacent fat infiltration, and a large amount of food in the stomach suggesting a passage disturbance, enlarged lymph nodes along the common hepatic and left gastric arteries, and multiple hepatic metastases. The serum carcinoembryonic antigen (CEA) level was 343 ng/ml and the carbohydrate antigen (CA) 19-9 level was within normal limits. The patient underwent a laparoscopic gastrojejunostomy for palliation of the GOO. On the 3^rdand 12^thdays after surgery, he received intraperitoneal chemotherapy with 40 mg of docetaxel and 150 mg of carboplatin. Simultaneously, combined chemotherapy with 85 mg/m²of oxaliplatin for the 1^stday and 600 mg/m²of 5-FU for 2 days (FOLFOX regimen) was administered from the 8^thpost-operative day. After completion of nine courses of FOLFOX, the patient achieved a complete response (CR) with complete disappearance of the primary tumor and the metastatic foci. He underwent a radical subtotal gastrectomy with D3 lymph node dissection 4 months after the initial palliative surgery. The pathologic results revealed no residual primary tumor and no lymph node metastasis in 43 dissected lymph nodes. He has maintained a CR for 18 months since the last operation.</p> <p>Conclusion</p> <p>Combination chemotherapy with systemic and intraperitoneal chemotherapy following laparoscopic bypass surgery showed marked efficacy in the treatment for unresectable advanced gastric cancer with GOO.</p