Spherical tarball particles form through rapid chemical and physical changes of organic matter in biomass-burning smoke.

Biomass burning (BB) emits enormous amounts of aerosol particles and gases into the atmosphere and thereby significantly influences regional air quality and global climate. A dominant particle type from BB is spherical organic aerosol particles commonly referred to as tarballs. Currently, tarballs can only be identified, using microscopy, from their uniquely spherical shapes following impaction onto a grid. Despite their abundance and potential significance for climate, many unanswered questions related to their formation, emission inventory, removal processes, and optical properties still remain. Here, we report analysis that supports tarball formation in which primary organic particles undergo chemical and physical processing within ∼3 h of emission. Transmission electron microscopy analysis reveals that the number fractions of tarballs and the ratios of N and O relative to K, the latter a conserved tracer, increase with particle age and that the more-spherical particles on the substrates had higher ratios of N and O relative to K. Scanning transmission X-ray spectrometry and electron energy loss spectrometry analyses show that these chemical changes are accompanied by the formation of organic compounds that contain nitrogen and carboxylic acid. The results imply that the chemical changes increase the particle sphericity on the substrates, which correlates with particle surface tension and viscosity, and contribute to tarball formation during aging in BB smoke. These findings will enable models to better partition tarball contributions to BB radiative forcing and, in so doing, better help constrain radiative forcing models of BB events.

First X-ray Spectroscopic Observations of Atmospheric Titanium Species: Size Dependence and the Emission Source.

Titanium dioxide (TiO2) in mineral dust is considered as one of the driving forces of photocatalytic reaction at the aerosol surface in the atmosphere. As a precursor of mineral dust, soil contains ilmenite (FeTiO3) and titanite (CaSiTiO5), which have lower photochemical reactivities than TiO2. However, Ti species other than TiO2 in aerosol particles are not well recognized due to the lack of observation in ambient samples. In this study, Ti species in size-fractionated aerosol samples collected in the Noto Peninsula, Japan, were determined by macroscopic and semi-microscopic X-ray absorption fine structure spectroscopy. Regardless of aerosol particle size, Ti species were primarily composed of rutile, anatase, ilmenite, and titanite. Semi-microscopic Ti speciation showed that Ti-poor spots associated with mineral dust were composed of a mixture of rutile, anatase, ilmenite, and titanite, and Ti-rich spots were primarily composed of TiO2 (rutile or anatase) derived from authigenic minerals or anthropogenic materials. Thus, the Ti species in aerosol particles, especially mineral dust, were not composed solely of TiO2 polymorphs. Therefore, the photochemical reactivities of Ti in aerosol particles may be overestimated when laboratory experiments or model studies employ TiO2 as the representative Ti species.

A prospective, observational, multicenter study on risk factors and prophylaxis for low emetic risk chemotherapy-induced nausea and vomiting.

PURPOSE: The incidence of and the risk factors for nausea and vomiting in patients undergoing low emetic risk chemotherapy (LEC) are unclear. The aim of the study was to provide information on these topics by performing a multicenter, observational, prospective study. METHODS: The study consisted of patients who were administered first-time LEC that was consistent or inconsistent with current guidelines. Using the visual analog scale, patients recorded their daily food intake and the occurrence and severity of nausea over a 5-day treatment period. RESULTS: The overall incidence of chemotherapy-induced nausea and vomiting did not differ significantly between patients undergoing guideline-consistent (n = 89) or guideline-inconsistent (n = 121) prophylaxis (30.3 vs. 22.3%, respectively; P = 0.19). Logistic regression analysis identified a history of nausea and LEC other than taxanes as independent risk factors associated with nausea and vomiting in patients undergoing LEC. The mean daily visual analog scale scores for nausea severity and a decrease in food intake were <25 mm throughout the entire observation period. CONCLUSIONS: Guideline-consistent prophylaxis appeared to control nausea and vomiting effectively in patients undergoing LEC. However, patients with a history of nausea and receiving LEC other than taxanes should be carefully observed and treatment should be adjusted according to their symptoms.

Identification of sources of lead in the atmosphere by chemical speciation using X-ray absorption near-edge structure (XANES) spectroscopy.

Sources of Pb pollution in the local atmosphere together with Pb species, major ions, and heavy metal concentrations in a size-fractionated aerosol sample from Higashi-Hiroshima (Japan) have been determined by X-ray absorption near-edge structure (XANES) spectroscopy, ion chromatography, and ICP-MS/AES, respectively. About 80% of total Pb was concentrated in fine aerosol particles. Lead species in the coarse aerosol particles were PbC2O4, 2PbCO3 Pb(OH)2, and Pb(NO3)2, whereas Pb species in the fine aerosol particles were PbC2O4, PbSO4, and Pb(NO3)2. Chemical speciation and abundance data suggested that the source of Pb in the fine aerosol particles was different from that of the coarse ones. The dominant sources of Pb in the fine aerosol particles were judged to be fly ash from a municipal solid waste incinerator and heavy oil combustion. For the coarse aerosol particles, road dust was considered to be the main Pb source. In addition to Pb species, elemental concentrations in the aerosols were also determined. The results suggested that Pb species in size-fractionated aerosols can be used to identify the origin of aerosol particles in the atmosphere as an alternative to Pb isotope ratio measurement.

Broadband high-energy resolution hard x-ray spectroscopy using transition edge sensors at SPring-8.

We have succeeded in operating a transition-edge sensor (TES) spectrometer and evaluating its performance at the SPring-8 synchrotron x-ray light source. The TES spectrometer consists of a 240 pixel National Institute of Standards and Technology (NIST) TES system, and 220 pixels are operated simultaneously with an energy resolution of 4 eV at 6 keV at a rate of ∼1 c/s pixel-1. The tolerance for high count rates is evaluated in terms of energy resolution and live time fraction, leading to an empirical compromise of ∼2 × 103 c/s (all pixels) with an energy resolution of 5 eV at 6 keV. By utilizing the TES's wideband spectroscopic capability, simultaneous multi-element analysis is demonstrated for a standard sample. We conducted x-ray absorption near-edge structure (XANES) analysis in fluorescence mode using the TES spectrometer. The excellent energy resolution of the TES enabled us to detect weak fluorescence lines from dilute samples and trace elements that have previously been difficult to resolve due to the nearly overlapping emission lines of other dominant elements. The neighboring lines of As Kα and Pb Lα2 of the standard sample were clearly resolved, and the XANES of Pb Lα2 was obtained. Moreover, the x-ray spectrum from the small amount of Fe in aerosols was distinguished from the spectrum of a blank target, which helps us to understand the targets and the environment. These results are the first important step for the application of high resolution TES-based spectroscopy at hard x-ray synchrotron facilities.

Risk factors for delayed chemotherapy-induced nausea and vomiting with low-emetic-risk chemotherapy: a prospective, observational, multicenter study.

PURPOSE: Improvement in the control of delayed chemotherapy-induced nausea and vomiting (CINV) is needed. There is limited information on antiemetic prophylaxis for patients undergoing low-emetic-risk chemotherapy (LEC), and the optimal antiemetic treatment is not well understood. Therefore, we analyzed the risk factors for delayed CINV to aid in the development of individualized treatments. PATIENTS AND METHODS: This prospective multicenter study was conducted in 13 hospitals and included patients with solid cancers undergoing LEC. A total of 222 patients were enrolled between September 2013 and November 2014. The participants completed a daily diary for 5 days after the commencement of the first cycle of LEC to describe the daily incidence of CINV (yes/no). Furthermore, the participants described the severity of nausea and the amount of food intake with the help of VAS. RESULTS: Two hundred and ten patients provided their data that were analyzed using multivariate logistic regression to examine the risk factors for delayed CINV. History of CINV, Eastern Cooperative Oncology Group performance status score ≥1, acute CINV, and single-day antiemetic prophylaxis were identified as independent risk factors for delayed CINV. CONCLUSION: The current use of antiemetic prophylaxis according to the recommended guideline appears to effectively control delayed CINV in patients undergoing LEC. Therefore, patients with the abovementioned risk factors should be carefully observed, and their treatment should be adjusted according to their symptoms. The use of multiple-day dexamethasone may be beneficial for those patients who develop acute CINV, especially when it is accompanied by anorexia.

Microfluidic devices for construction of contractile skeletal muscle microtissues.

Cell-culture microchips mimicking tissue/organ-specific functions are required as alternatives to animal testing for drug discovery and disease models. Although three-dimensional (3D) cell culture microfluidic devices can create more biologically relevant cellular microenvironments and higher throughput analysis platforms of cell behavior than conventional techniques, devices for skeletal muscle cells have not been developed. In the present study, we aimed to develop microfluidic devices for 3D cultures of skeletal muscle cells. Skeletal muscle cells mixed with a collagen type-I solution was introduced into the microchannel for cells (MC-C) and was gelated. Then, the medium was introduced into the microchannel for medium (MC-M). During this process, connecting microchannels (Con-MCs) prevented leakage of the collagen solution mixed with cells from MC-C to MC-M and supplied the nutrients from the medium in MC-M to the cells in MC-C. Skeletal muscle microtissues cultured in the microchannel for a week consisted of myotubes were confirmed by histological analysis and immunofluorescence staining. The skeletal muscle microtissues in the microchannel contracted in response to externally applied electrical stimulation (1 and 50 Hz). These results indicate that the functional skeletal muscle microtissues were constructed in the microchannel. Thus, the microfluidic device for culturing 3D skeletal muscle microtissues presented in this study has a potential to be used for drug discovery and toxicological tests.