Determination of nitrated polycyclic aromatic hydrocarbons in particulate matter 2.5 by laser ionization mass spectrometry using an on-line chemical-reduction system.

Nitrated polycyclic aromatic hydrocarbons (NPAHs) were separated by gas chromatography (GC) and were introduced into a reactor consisting of an inner-seal Y-connector for the on-line chemical reduction of NPAH using hydrazine monohydrate as a chemical reducing agent. The reduced forms of amino polycyclic aromatic hydrocarbons (APAHs) were then determined by multiphoton ionization time-of-flight mass spectrometry (MPI/TOF-MS) using a femtosecond laser as the ionization source. Three standard samples of NPAHs, i.e., 9-nitroanthracene (9-NANT), 3-nitrofluoranthene (3-NFLU), and 1-nitropyrene (1-NPYR), were confirmed to be completely reduced to the corresponding APAHs, i.e., 9-aminoanthracene (9-AANT), 3-aminofluoranthene (3-AFLU), and 1-aminopyrene (1-APYR). The sensitivity of the method was improved by 2-8 fold by converting the NPAHs to APAHs. This analytical technique was applied to a sample extracted from PM2.5 collected in Fukuoka. The signal enhancement and background reduction by the chemical reaction resulted in the NPAHs in the actual sample being more efficiently measured, and the concentrations of 9-NANT, 3-NFLU, and 1-NPYR were determined to be 25, 305, and 217 pg m-3, respectively.

Seasonal Fluctuations in Air Pollution in Dazaifu, Japan, and Effect of Long-Range Transport from Mainland East Asia.

To clarify the seasonal fluctuations in air pollution and the effect of long-range transport, we collected airborne particles (n=118) at Dazaifu in Fukuoka, Japan, from June 2012 to May 2013 and measured Pb and SO4(2-), which are indicators of the long-range transport of anthropogenic air pollutants, as well as their mutagenicity, and other factors. The levels of airborne particles, Pb, and SO4(2-) were very high on March 4, 8, 9, and 19, and May 13, 21, and 22, 2013. The backward trajectories indicated that air masses had arrived from the Gobi Desert and northern China on those days. The mutagenicity of airborne particles was examined using the Ames test on Salmonella typhimurium YG1024. Highly mutagenic airborne particles were mostly collected in winter, and most of them showed high activity both with and without S9 mix. High levels of polycyclic aromatic hydrocarbons (PAHs) were found in many samples that showed high mutagenicity. For the samples collected on January 30, February 21, and March 4, the levels of Pb, SO4(2-), PAHs, and mutagenicity were high, and the backward trajectories indicated that air masses present on those days had passed through northern or central China. The Japan Meteorological Agency registered Asian dust events at Fukuoka on March 8, 9, and 19, 2013. The results of the present study suggest that high levels of anthropogenic air pollutants were transported with Asian dust. Similarly, long-range transport of air pollutants including mutagens occurred on days when Asian dust events were not registered.

[Development, manufacture and sales of products for diagnosis of disease].

Final version of "Chronic kidney disease (CKD) Practice Guide" book is displayed on the Japanese Society of Nephrology (JSN) homepage in April, 2007. JSN epidemiology working-group finally approved the glomerular filtration rate (GFR) estimation equation for Japanese. Serum creatinine (Cr) should be measured by enzyme method. The modified the abbreviated MDRD Study equation for Japanese is already printed in the "CKD practice guide". GFR = 175 x Cr(-1.154) x Age (-0.203) x 0.741 (if women 0.742) The limit of detection of enzymatic method of serum creatinine is at least 0.02 mg/dL to evaluate GFR accurately. Moreover, Japanese Government will assume decreasing the number of the prevalence and reserve of the lifestyle related disease up to present 25% to be a policy objective by 2015. And, it obligated the checkup and the health guidance specially provided to the employee of 40 years or more who worked in each corporation to be executed on April 1, 2008. The spread of the automatic clinical analyzer reduces a necessary amount of the specimen and the amount of the reagent, and has reduced time and the cost of clinical chemistry test greatly. The environment of the clinical examination will change in the future, and useful information for the patient and the doctor change again like this. To offer information suitable for needs in the changing age, the researcher who works at the site of the clinical examination and the researcher who works at the site of the reagent development should cooperate mutually, and continue study and the effort.

Seasonal variabilities in chemical compounds and acidity of aerosol particles at urban site in the west Pacific.

Mass concentrations of chemical compounds in both PM2.5 (particle aerodynamic diameter, Dp < 2.5 µm) and PM2.5-10 (2.5 < Dp < 10 µm), and acidity of aerosol particles were measured at an urban site in western Japan using a continuous dichotomous Aerosol Chemical Speciation Analyzer (ACSA-12) throughout 2014. Mass concentrations of both PM2.5 and sulfate had distinct seasonal variabilities with maxima in spring and winter, mostly due to long-range transport with the prevailing westerly wind. Mass concentration of nitrate in PM2.5 (fNO3) showed an obvious warm-season-low and cold-season-high pattern as a result of both gas-aerosol phase equilibrium processes under high temperature conditions as well as transport. Nitrate in PM2.5-10 (cNO3) increased during long-range transport of dust, implying the great importance of heterogeneous processes at the surface of coarse mode particles. In this study, Δ[H+] (derived from the difference in pH of extract liquid with/without sampling) was used to indicate the acidity of particles. We found that acidity of particles in PM2.5 (fΔH) was mostly positive with a maximum in August because of the large fraction of nitrate and sulfate. Acidity of particles in PM2.5-10 (cΔH) was negative in winter and spring due to presence of alkaline matter from crustal sources. This study highlights the great importance of anthropogenic pollutants on the acidity of particles in the western Pacific Ocean and further impact on the marine environment and climate.

Importance of mineral dust and anthropogenic pollutants mixing during a long-lasting high PM event over East Asia.

A long-lasting high particulate matter (PM) concentration episode persisted over East Asia from May 24 to June 3, 2014. The Nested Air Quality Prediction Model System (NAQPMS) was used to investigate the mixing of dust and anthropogenic pollutants during this episode. Comparison of observations revealed that the NAQPMS successfully reproduced the time series PM2.5 and PM10 concentrations, as well as the nitrate and sulfate concentrations in fine (aerodynamic diameter ≤ 2.5 µm) and coarse mode (2.5 µm < aerodynamic diameter ≤ 10 µm). This episode originated from two dust events that occurred in the inland desert areas of Mongolia and China, and then the long-range transported dust and anthropogenic pollutants were trapped over the downwind region of East Asia for more than one week due to the blocked north Pacific subtropical high-pressure system over the east of Japan. The model results showed that mineral dust accounted for 53-83% of PM10, and 39-67% of PM2.5 over five cities in East Asia during this episode. Sensitivity analysis indicated that the Qingdao and Seoul regions experienced dust and pollution twice, by direct transport from the dust source region and from dust detoured over the Shanghai area. The results of the NAQPMS model confirmed the importance of dust heterogeneous reactions (HRs) over East Asia. Simulated dust NO3- concentrations accounted for 75% and 84% of total NO3- in fine and coarse mode, respectively, in Fukuoka, Japan. The horizontal distribution of model results revealed that the ratio of dust NO3-/dust concentration increased from about 1% over the Chinese land mass to a maximum of 8% and 6% respectively in fine and coarse mode over the ocean to the southeast of Japan, indicating that dust NO3- was mainly formed over the Yellow Sea and the East China Sea before reaching Japan.

Real-time observational evidence of changing Asian dust morphology with the mixing of heavy anthropogenic pollution.

Natural mineral dust and heavy anthropogenic pollution and its complex interactions cause significant environmental problems in East Asia. Due to restrictions of observing technique, real-time morphological change in Asian dust particles owing to coating process of anthropogenic pollutants is still statistically unclear. Here, we first used a newly developed, single-particle polarization detector and quantitatively investigate the evolution of the polarization property of backscattering light reflected from dust particle as they were mixing with anthropogenic pollutants in North China. The decrease in observed depolarization ratio is mainly attributed to the decrease of aspect ratio of the dust particles as a result of continuous coating processes. Hygroscopic growth of Calcium nitrate (Ca(NO3)2) on the surface of the dust particles played a vital role, particularly when they are stagnant in the polluted region with high RH conditions. Reliable statistics highlight the significant importance of internally mixed, 'quasi-spherical' Asian dust particles, which markedly act as cloud condensation nuclei and exert regional climate change.

Determination of polycyclic aromatic hydrocarbons and their nitro-, amino-derivatives absorbed on particulate matter 2.5 by multiphoton ionization mass spectrometry using far-, deep-, and near-ultraviolet femtosecond lasers.

Multiphoton ionization processes of parent-polycyclic aromatic hydrocarbons (PPAHs), nitro-PAHs (NPAHs), and amino-PAHs (APAHs) were examined by gas chromatography combined with time-of-flight mass spectrometry using a femtosecond Ti:sapphire laser as the ionization source. The efficiency of multiphoton ionization was examined using lasers emitting in the far-ultraviolet (200 nm), deep-ultraviolet (267 nm), and near-ultraviolet (345 nm) regions. The largest signal intensities were obtained when the far-ultraviolet laser was employed. This favorable result can be attributed to the fact that these compounds have the largest molar absorptivities in the far-ultraviolet region. On the other hand, APAHs were ionized more efficiently than NPAHs in the near-ultraviolet region because of their low ionization energies. A sample extracted from a real particulate matter 2.5 (PM2.5) sample was measured, and numerous signal peaks arising from PAH and its analogs were observed at 200 nm. On the other hand, only a limited number of signed peaks were observed at 345 nm, some of which were signed to PPAHs, NPAHs, and APAHs. Thus, multiphoton ionization mass spectrometry has potential for the use in comprehensive analysis of toxic environmental pollutants.

Analysis of Parent/Nitrated Polycyclic Aromatic Hydrocarbons in Particulate Matter 2.5 Based on Femtosecond Ionization Mass Spectrometry.

Particulate matter 2.5 (PM2.5), collected from ambient air in Fukuoka City, was analyzed by gas chromatography combined with multiphoton ionization mass spectrometry using an ultraviolet femtosecond laser (267 nm) as the ionization source. Numerous parent polycyclic aromatic hydrocarbons (PPAHs) were observed in a sample extracted from PM2.5, and their concentrations were determined to be in the range from 30 to 190 pg/m(3) for heavy PPAHs. Standard samples of nitrated polycyclic aromatic hydrocarbons (NPAHs) were examined, and the limits of detection were determined to be in the picogram range. The concentration of NPAH adsorbed on PM2.5 in the air was less than 900-1300 pg/m(3). Graphical Abstract ᅟ.

Multiphoton ionization mass spectrometry of nitrated polycyclic aromatic hydrocarbons.

In order to suppress the fragmentation and improve the sensitivity for determination of nitrated polycyclic aromatic hydrocarbons (NPAHs), the mechanism of multiphoton ionization was studied for the following representative NPAHs, 9-nitroanthracene, 3-nitrofluoranthene, and 1-nitropyrene. The analytes were extracted from the PM2.5 on the sampling filter ultrasonically, and were measured using gas chromatography/multiphoton ionization/time-of-flight mass spectrometry with a femtosecond tunable laser in the range from 267 to 405 nm. As a result, a molecular ion was observed as the major ion and fragmentation was suppressed at wavelengths longer than 345 nm. Furthermore, the detection limit measured at 345 nm was measured to be the subpicogram level. The organic compounds were extracted from a 2.19 mg sample of particulate matter 2.5 (PM2.5), and the extract was subjected to multiphoton ionization mass spectrometry after gas chromatograph separation. The background signals were drastically suppressed at 345 nm, and the target NPAHs, including 9-nitroanthracene and 1-nitropyrene, were detected, and their concentrations were determined to be 5 and 3 pg/m(3), respectively.

A convenient enzyme-linked immunosorbent assay for rapid screening of anti-adeno-associated virus neutralizing antibodies.

BACKGROUND: Recombinant adeno-associated virus vectors based on serotype 2 (AAV-2) have become leading vehicles for gene therapy. Most humans in the general population have anti-AAV-2 antibodies as a result of naturally acquired infections. Pre-existing immunity to AAV-2 might affect the functional and safety consequences of AAV-2 vector-mediated gene transfer in clinical applications. METHODS: An enzyme-linked immunosorbent assay (ELISA) method was developed using microwell plates coated with intact particles of recombinant AAV-2 vectors, and horseradish peroxidase-conjugated anti-human immunoglobulin G (HRP-IgG). Neutralizing antibody titres were analysed by assessing the ability of serum antibody to inhibit transduction into HEK293 cells of AAV vectors that express beta-galactosidase. RESULTS: Anti-AAV-2 antibodies were detected by ELISA in two of 20 healthy subjects. The positivity criterion (optical density >0.5) in ELISA corresponded to the cut-off value (320-fold dilution of serum) in the AAV-2 neutralization assay. Influences of interfering substances were not observed. CONCLUSION: This ELISA method may be useful for rapid screening of anti-AAV-2 neutralizing antibodies in candidates for gene therapy.