Microplastics (MPs) are ubiquitously spread in water environment and have raised global concerns due to their adverse effect to biological and ecological systems. Wastewater treatment plants have ...been reported to be an important route of releasing MPs into the environment. As a great source of MPs in number in wastewater, the characteristics of microbeads have hardly been studied. In this study, the variation of the characteristics of microbeads prior to and after incubating in wastewater samples has been identified. Reported digestion methods of acid, alkaline, enzymatic, and wet preoxidation digestion were subsequently applied to assess their efficacy for digesting microbeads from the wastewater, and enzymatic digestion has shown the optimal efficacy. Finally, enzymatic digestion was applied to evaluate microbeads and other MPs in real wastewater treatment plant samples. It is shown that the sequential treatment of fine screen, grit chamber, and improved sequencing batch reactor activated sludge processes were able to remove 72% pellets in number and 43% MPs in total, while a large portion was still remaining after the secondary treatment. This study set a base for understanding the characteristics and occurrence of MPs, especially microbeads in wastewater samples.
Ozone is an important pollutant and greenhouse gas, and tropospheric ozone variations are generally associated with both natural and anthropogenic processes. As one of the most pristine and ...inaccessible regions in the world, the Tibetan Plateau has been considered as an ideal region for studying processes of the background atmosphere. Due to the vast area of the Tibetan Plateau, sites in the southern, northern and central regions exhibit different patterns of variation in surface ozone. Here, we present continuous measurements of surface ozone mixing ratios at Nam Co Station over a period of ∼ 5 years (January 2011 to October 2015), which is a background site in the inland Tibetan Plateau. An average surface ozone mixing ratio of 47.6 ± 11.6 ppb (mean ± standard deviation) was recorded, and a large annual cycle was observed with maximum ozone mixing ratios in the spring and minimum ratios during the winter. The diurnal cycle is characterized by a minimum in the early morning and a maximum in the late afternoon. Nam Co Station represents a background region where surface ozone receives negligible local anthropogenic emissions inputs, and the anthropogenic contribution from South Asia in spring and China in summer may affect Nam Co Station occasionally. Surface ozone at Nam Co Station is mainly dominated by natural processes involving photochemical reactions, vertical mixing and downward transport of stratospheric air mass. Model results indicate that the study site is affected differently by the surrounding areas in different seasons: air masses from the southern Tibetan Plateau contribute to the high ozone levels in the spring, and enhanced ozone levels in the summer are associated with air masses from the northern Tibetan Plateau. By comparing measurements at Nam Co Station with those from other sites on the Tibetan Plateau, we aim to expand the understanding of ozone cycles and transport processes over the Tibetan Plateau. This work may provide a reference for future model simulations.
Recent genomic sequencing efforts have identified a number of recurrent mutations in myelodysplastic syndromes (MDS) that may contribute to disease progression and overall survival, including ...mutations in isocitrate dehydrogenases 1 and 2 (IDH1 and IDH2).
Pretreatment bone marrow (BM) samples were acquired from mononuclear cells in 146 adult patients with de novo MDS from January 2006 to June 2013. Polymerase chain reaction (PCR) and direct sequencing were performed on exon 4 of IDH1/2 genes and mutation status was correlated with overall survival (OS) and leukemia-free survival (LFS). We then performed a meta-analysis combining previously published and current studies to explore the effect of IDH mutations on OS and LFS in MDS.
In our study, somatic mutations of either IDH gene were discovered in 11 MDS patients (7.53%) and were significantly correlated with poorer OS (P = 0.007). IDH mutations were specifically associated with a poorer OS in the intermediate-1 risk group by the International Prognostic Scoring System (IPSS) (P = 0.039). In addition, we discovered decitabine achieved a better therapeutic effect compared to other treatments in IDH mutation-positive patients (P = 0.023). We identified six previous studies of IDH mutations in MDS. A meta-analysis of these studies included 111 MDS patients IDH mutations and 1671 MDS patients with wild-type IDH1/2. The hazard ratios (HRs) of OS and LFS for patients with IDH mutations were 1.62 (95% CI, 1.27-2.09) and 2.21 (95% CI, 1.48-3.30), respectively.
The results from our study and the meta-analysis provide firm evidence that IDH mutations are significantly associated with poorer clinical outcomes in MDS. Identification of IDH mutations may be pivotal for better risk stratification in MDS patients and improving IPSS score. Additionally, hypomethylating agents may be an effective treatment option for MDS patients with IDH mutations.
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•Highest air pollution concentration mostly in winter or in spring.•O3 peaked in the afternoon while other pollutants had a bimodal pattern.•Transboundary transport of air pollutants ...from South Asia and Southeast Asia.
Air pollution is a grand challenge of our time due to its multitude of adverse impacts on environment and society, with the scale of impacts more severe in developing countries, including China. Thus, China has initiated and implemented strict air pollution control measures over last several years to reduce impacts of air pollution. Monitoring data from Jan 2015 to Dec 2019 on six criteria air pollutants (SO2, NO2, CO, O3, PM2.5, and PM10) at eight sites in southwestern China were investigated to understand the situation and analyze the impacts of transboundary air pollutants in this region. In terms of seasonal variation, the maximum concentrations of air pollutants at these sites were observed in winter or spring season depending on individual site. For diurnal variation, surface ozone peaked in the afternoon while the other pollutants had a bimodal pattern with peaks in the morning and late afternoon. There was limited transport of domestic emissions of air pollutants in China to these sites. Local emissions enhanced the concentrations of air pollutants during some pollution events. Mostly, the transboundary transport of air pollution from South Asia and Southeast Asia was associated with high concentrations of most air pollutants observed in southwestern China. Since air pollutants can be transported to southwestern China over long distances from the source regions, it is necessary to conduct more research to properly attribute and quantify transboundary transport of air pollutants, which will provide more solid scientific guidance for air pollution management in southwestern China.
Located in the world's “third pole” and a remote region
connecting the Indian plate and the Eurasian plate, Qomolangma National
Nature Preserve (QNNP) is an ideal region to study the long-range ...transport
of atmospheric pollutants. In this study, gaseous elemental mercury (GEM),
gaseous oxidized mercury (GOM) and particle-bound mercury (PBM) were
continuously measured during the Indian monsoon transition period in QNNP. A
slight increase in the GEM concentration was observed from the period preceding the
Indian summer monsoon (1.31±0.42 ng m−3) to the Indian
summer monsoon period (1.44±0.36 ng m−3), while significant
decreases were observed in the GOM and PBM concentrations, with concentrations
decreasing from 35.2±18.6 to 19.3±10.9 pg m−3 (p < 0.001) for GOM and from 30.5±12.5 to 24.9±19.8 pg m−3
(p < 0.001) for PBM. A unique daily pattern was
observed in QNNP with respect to the GEM concentration,
with a peak value before sunrise and a low value at noon.
Relative to the (low) GEM concentrations, GOM concentrations (with a mean value
of 21.4±13.4 pg m−3, n=1239) in this region were relatively
high compared with the measured values in some other regions of China. A
cluster analysis indicated that the air masses transported to QNNP changed
significantly at different stages of the monsoon, and the major potential mercury
(Hg) sources shifted from northern India and western Nepal to eastern Nepal and Bangladesh.
As there is a large area covered in glaciers in QNNP, local glacier
winds could increase the transboundary transport of pollutants and transport
polluted air masses to the Tibetan Plateau. The atmospheric Hg concentration
in QNNP in the Indian summer monsoon period was influenced by transboundary
Hg flows. This highlights the need for a more specific identification of Hg
sources impacting QNNP and underscores the importance of international
cooperation regarding global Hg controls.
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•OC and EC exhibit much high concentrations in pre-monsoon season.•The ffossil to atmospheric EC (47.9%) is consistent with that of South Asia.•Local biomass burning cause the lowest ...ffossil (27.7%) in winter besides regional transport.•WSOC plays an important role in absorbing solar radiation with contribution as 11.1%
The Indo-Gangetic Plain (IGP) is a major regional and global emitter of atmospheric pollutants, which adversely affect surrounding areas such as the Himalayas. We present a comprehensive dataset on carbonaceous aerosol (CA) composition, radiocarbon (Δ14C) -based source apportionment, and light absorption of total suspended particle (TSP) samples collected over a 3-year period from high-altitude Jomsom in the central Himalayas. The 3-year mean TSP, organic carbon (OC), and elemental carbon (EC) concentrations were 92.0 ± 28.6, 9.74 ± 6.31, and 2.02 ± 1.35 μg m−3, respectively, with the highest concentrations observed during the pre-monsoon season, followed by the post-monsoon, winter, and monsoon seasons. The Δ14C analysis revealed that the contribution of fossil fuel combustion (ffossil) to EC was 47.9% ± 11.5%, which is consistent with observations in urban and remote regions in South Asia and attests that EC likely arrives in Jomsom from upwind IGP sources via long-range transport. In addition, the lowest ffossil (38.7% ± 13.3%) was observed in winter, indicating large contributions in this season from local biomass burning. The mass absorption cross-section of EC (MACEC: 8.27 ± 1.76 m2/g) and water-soluble organic carbon (MACWSOC: 0.98 ± 0.45 m2/g) were slightly higher and lower than those reported in urban regions, respectively, indicating that CA undergo an aging process. Organic aerosol coating during transport and variation of biomass burning probably led to the seasonal variation in MAC of two components. Overall, WSOC contributed considerably to the light absorption (11.1% ± 4.23%) of EC. The findings suggest that to protect glaciers of the Himalayas from pollution-related melting, it is essential to mitigate emissions from the IGP.
Black carbon (BC) aerosol impacts the air quality, public health, agricultural productivity, weather, monsoon, cryosphere, and climate system from the local to the global scale. However, its ...distribution over vast Central Asia is poorly known, because it is one of the poorly sampled regions of the world. BC in the soil can be resuspended into the atmosphere and transported to downwind regions with sensitive ecosystems and vulnerable populations, such as from Central Asian countries to the cryospheric regions in the Tianshan Mountain and the Tibetan Plateau, which could accelerate the melting of the snowfields and glaciers. We report the distribution of BC and total organic carbon (TOC) in surface soil with samples collected at multiple sites, for the first time, over three countries in Central Asia (Uzbekistan, Tajikistan, and Kyrgyzstan). The mean BC (TOC) concentrations over three countries were 0.06 ± 0.06 (11.86 ± 4.84) mg g
−1
, 0.15 ± 0.21 (20.35 ± 10.96) mg g
−1
, and 0.32 ± 0.29 (26.45 ± 20.38) mg g
−1
, respectively. They were found to be originated from the same or similar sources, at least over Tajikistan and Kyrgyzstan, as indicated by their high and significant correlation (
R
2
> 0.6,
p
< 0.001). The char/soot ratio indicated the diesel and gasoline combustion as dominant BC sources over this region. To gain further insights into the soil BC and its implications to air quality, climate, and cryosphere, future studies should include a wider area over Central Asia with different land-use types and other soil parameters combined with atmospheric simulations for this important yet relatively less studied region of the world.
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•Indian summer monsoon and stratospheric intrusion impact air pollutants in Tibetan Plateau.•Decrease in particulate pollutants and increase in gaseous pollutants.•Surface ozone at ...Nam Co Station was primarily affected by stratospheric intrusion events.
Air pollutants can be transported to the pristine regions such as the Tibetan Plateau, by monsoon and stratospheric intrusion. The Tibetan Plateau region has limited local anthropogenic emissions, while this region is influenced strongly by transport of heavy emissions mainly from South Asia. We conducted a comprehensive study on various air pollutants (PM2.5, total gaseous mercury, and surface ozone) at Nam Co Station in the inland Tibetan Plateau. Monthly mean PM2.5 concentration at Nam Co peaked in April before monsoon season, and decreased during the whole monsoon season (June–September). Monthly mean total gaseous mercury concentrations at Nam Co peaked in July and were in high levels during monsoon season. The Indian summer monsoon acted as a facilitator for transporting gaseous pollutants (total gaseous mercury) but a suppressor for particulate pollutants (PM2.5) during the monsoon season. Different from both PM2.5 and total gaseous mercury variabilities, surface ozone concentrations at Nam Co are primarily attributed to stratospheric intrusion of ozone and peaked in May. The effects of the Indian summer monsoon and stratospheric intrusion on air pollutants in the inland Tibetan Plateau are complex and require further studies.
Disseminated candidiasis is a severe complication in patients with hematological malignancies who have undergone chemotherapy or hematopoietic stem cell transplantation. It has a high mortality rate. ...When disseminated candidiasis caused by Candida tropicalis involves either the brain or heart, the prognosis is extremely poor. Traditional methods such as cultures are limited in diagnosing disseminated candidiasis. We describe a case report of a 55-year-old man with acute myeloid leukemia who developed candidemia caused by Candida tropicalis after chemotherapy, which disseminated extensively to the heart, brain, skin, liver, spleen and kidneys. In this instance, the patient was rapidly diagnosed with candida infection by metagenomic next generation sequencing, and successfully treated with combination therapy of isavuconazole and amphotericin B. The patient continued with treatment of leukemia while simultaneously receiving antifungal therapy, and both leukemia and disseminated candidiasis were effectively controlled. This case report provides real-world experience for treatment of patients with leukemia complicated by disseminated candidiasis.
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•Mean AOD was higher by a factor of ~3, 3.5 and 6.6 during aerosol events.•Aerosol events resulted in enhancement of atmospheric ARF by ~1.7–2.3.•Local and regional scale air mass ...transported the aerosols.
The location of Central Asia, almost at the center of the global dust belt region, makes it susceptible for dust events. The studies on atmospheric impact of dust over the region are very limited despite the large area occupied by the region and its proximity to the mountain regions (Tianshan, Hindu Kush-Karakoram-Himalayas, and Tibetan Plateau). In this study, we analyse and explain the modification in aerosols’ physical, optical and radiative properties during various levels of aerosol loading observed over Central Asia utilizing the data collected during 2010–2018 at the AERONET station in Dushanbe, Tajikistan. Aerosol episodes were classified as strong anthropogenic, strong dust and extreme dust. The mean aerosol optical depth (AOD) during these three types of events was observed a factor of ~3, 3.5 and 6.6, respectively, higher than the mean AOD for the period 2010–2018. The corresponding mean fine-mode fraction was 0.94, 0.20 and 0.16, respectively, clearly indicating the dominance of fine-mode anthropogenic aerosol during the first type of events, whereas coarse-mode dust aerosol dominated during the other two types of events. This was corroborated by the relationships among various aerosol parameters (AOD vs. AE, and EAE vs. AAE, SSA and RRI). The mean aerosol radiative forcing (ARF) at the top of the atmosphere (ARFTOA), the bottom of the atmosphere (ARFBOA), and in the atmosphere (ARFATM) were −35 ± 7, −73 ± 16, and 38 ± 17 Wm−2 during strong anthropogenic events, −48 ± 12, −85 ± 24, and 37 ± 15 Wm−2 during strong dust event, and −68 ± 19, −117 ± 38, and 49 ± 21 Wm−2 during extreme dust events. Increase in aerosol loading enhanced the aerosol-induced atmospheric heating rate to 0.5–1.6 K day−1 (strong anthropogenic events), 0.4–1.9 K day−1 (strong dust events) and 0.8–2.7 K day−1 (extreme dust events). The source regions of air masses to Dushanbe during the onset of such events are also identified. Our study contributes to the understanding of dust and anthropogenic aerosols, in particular the extreme events and their disproportionally high radiative impacts over Central Asia.
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