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1.
Sci Total Environ ; 930: 172763, 2024 Jun 20.
Article in English | MEDLINE | ID: mdl-38670373

ABSTRACT

Surface ozone pollution, as a pressing environmental concern, has garnered widespread attention across China. Due to air mass transport, effective control of ozone pollution is highly dependent on collaborative efforts across neighboring regions. However, specific regions with strong internal interactions of ozone pollution are not yet well identified. Here, we introduced the Geospatial SHapley Additive exPlanation (GeoSHAP) approach, which primarily involves machine learning and geostatistical algorithms. Based on extensive atmospheric environmental monitoring data from 2017 to 2021, machine learning models were employed to train and predict ozone concentrations at the target location. The R2 values on the test sets of different scale regions all reached 0.98 in the overall condition, indicating that the core model has good accuracy and generalization ability. The results highlight key regions with high ozone geospatial relationship (OGR) index, predominantly located in the Northern District (ND), spanning the Fen-Wei Plain, the Loess Plateau, and the North China Plain, as well as within portions of the Yangtze River Delta (YRD) and the Pearl River Delta (PRD). Further investigation indicated that high geospatial relationships stem from a synergy between anthropogenic and natural factors, with anthropogenic factors serving as a pivotal element. This study revealed key regions with the most urgent need for joint control of anthropogenic sources to mitigate ozone pollution.

2.
Inorg Chem ; 63(12): 5761-5768, 2024 Mar 25.
Article in English | MEDLINE | ID: mdl-38485515

ABSTRACT

The reasonably constructed high-performance electrocatalyst is crucial to achieve sustainable electrocatalytic water splitting. Alloying is a prospective approach to effectively boost the activity of metal electrocatalysts. However, it is a difficult subject for the controllable synthesis of small alloying nanostructures with high dispersion and robustness, preventing further application of alloy catalysts. Herein, we propose a well-defined molecular template to fabricate a highly dispersed NiRu alloy with ultrasmall size. The catalyst presents superior alkaline hydrogen evolution reaction (HER) performance featuring an overpotential as low as 20.6 ± 0.9 mV at 10 mA·cm-2. Particularly, it can work steadily for long periods of time at industrial-grade current densities of 0.5 and 1.0 A·cm-2 merely demanding low overpotentials of 65.7 ± 2.1 and 127.3 ± 4.3 mV, respectively. Spectral experiments and theoretical calculations revealed that alloying can change the d-band center of both Ni and Ru by remodeling the electron distribution and then optimizing the adsorption of intermediates to decrease the water dissociation energy barrier. Our research not only demonstrates the tremendous potential of molecular templates in architecting highly active ultrafine nanoalloy but also deepens the understanding of water electrolysis mechanism on alloy catalysts.

3.
World J Clin Cases ; 11(29): 7127-7135, 2023 Oct 16.
Article in English | MEDLINE | ID: mdl-37946762

ABSTRACT

BACKGROUND: Digital subtraction angiography (DSA), the gold standard of cerebrovascular disease diagnosis, is limited in its diagnostic ability to evaluate arterial diameter. Intravascular ultrasonography (IVUS) has advantages in assessing stenosis and plaque nature and improves the evaluation and effectiveness of carotid artery stenting (CAS). CASE SUMMARY: Case 1: A 65-year-old man presented with a five-year history of bilateral lower limb weakness due to stroke. Physical examination showed decreased strength (5-/5) in both lower limbs. Carotid artery ultrasound, magnetic resonance angiography, and computed tomography angiography (CTA) showed a right proximal internal carotid artery (ICA) stenosis (70%-99%), acute cerebral infarction, and severe right ICA stenosis, respectively. We performed IVUS-assisted CAS to measure the stenosis and detected a low-risk plaque at the site of stenosis prior to stent implantation. Post-stent balloon dilatation was performed and postoperative IVUS demonstrated successful expansion and adherence. CTA six months postoperatively showed no significant increase in in-stent stenosis. Case 2: A 36-year-old man was admitted with a right common carotid artery (CCA) dissection detected by ultrasound. Physical examination showed no positive neurological signs. Carotid ultrasound and CTA showed lumen dilation in the proximal CCA with an intima-like structure and bulging in the proximal segment of the right CCA with strip-like low-density shadow (dissection or carotid web). IVUS-assisted DSA confirmed right CCA dissection. CAS was performed and intraoperative IVUS suggested a large residual false lumen. Post-stent balloon dilatation was performed reducing the false lumen. DSA three months postoperatively indicated good stent expansion with mild stenosis. CONCLUSION: IVUS aids decision-making during CAS by accurately assessing carotid artery wall lesions and plaque nature preoperatively, dissection and stenosis morphology intraoperatively, and visualizing and confirming CAS postoperatively.

4.
World J Clin Cases ; 11(21): 5047-5055, 2023 Jul 26.
Article in English | MEDLINE | ID: mdl-37583850

ABSTRACT

BACKGROUND: Mechanical thrombectomy is the most effective treatment for great cerebral artery embolization within a set time window. Typically, an arteriogram does not show the localization of the stent after release and whether a thrombus is captured or not. Thus, improving the visualization of a stent in interventional therapy will be helpful for clinicians. AIM: To analyze stent imaging findings to enhance clinicians' understanding of a special circumstance, wherein a Solitaire AB retrievable stent was visible during the imaging of a thrombus capture that improved the success rate of stent-based mechanical thrombectomy. METHODS: This was a retrospective study with four acute ischemic stroke (AIS) patients who underwent stent-based mechanical thrombectomy. RESULTS: Patient 1 was a 64-year-old man admitted after 5 h of confusion; angiography revealed basilar artery occlusion. We inserted a stent into the left posterior cerebral artery-P2 segment and visualized the expanded stent that successfully captured a thrombus. Patient 2 was a 74-year-old man admitted with confusion, which lasted approximately 3 h. Angiography revealed a left middle cerebral artery (MCA)-M1 segment occlusion. A stent was deployed in the distal M2 segment, and we could visualize the stent by capturing the thrombus. Patient 3 was a 74-year-old woman admitted after experiencing left hemiplegia for 3 h. We deployed a stent at the distal right MCA-M2 segment, and the developing stent captured a large thrombus. Patient 4 was an 82-year-old man who presented with confusion for 3 h. A developing stent was placed in the distal left MCA-M1 segment, which captured a large thrombus and several fragmented thrombi. CONCLUSION: To the best of our knowledge, this is the first report of stent imaging in patients with AIS. We demonstrated the usefulness and substantial potential of stent imaging in stent-based mechanical thrombectomy for AIS.

5.
Sci Total Environ ; 897: 166394, 2023 Nov 01.
Article in English | MEDLINE | ID: mdl-37597544

ABSTRACT

The evolution of black carbon (BC) particles during atmospheric aging led to the complexity of their environmental and climate effect assessment. This study simultaneously measured the heterogeneous distribution of multi-level microphysical properties of BC-containing particles (i.e., BC mass concentration, coating amounts, and morphology) by a suite of state-of-the-art instruments, and investigated how atmospheric processing influence these heterogeneities. Our field measurements show that the mixing states of atmospheric BC-containing particles exhibit a clear dependence on BC core diameters. The particles with small BC core sizes (80-160 nm) are coated and reshaped more rapidly in real atmosphere, with coating-to-BC mass ratios (MR) and non-spherical fractions of 5.1 ± 1.2 and 61 ± 19 %, respectively. Conversely, the particles with large core sizes (240-320 nm) are thinly coated and fractal, with MR and non-spherical fractions of 4.0 ± 0.3 and 74 ± 15 %, respectively. Furthermore, primary emissions result in low heterogeneity in coating amount but great heterogeneity in morphology between BC-containing particles of different sizes, while photochemical processing would enhance heterogeneity in coating amount but weaken the heterogeneity in morphology. Overall, our field measurement of multi-level microphysical properties highlights that BC core size and atmospheric processing are the key factors that drive the heterogeneity evolution of BC-containing particles in real atmosphere.

6.
Sci Total Environ ; 892: 164662, 2023 Sep 20.
Article in English | MEDLINE | ID: mdl-37277044

ABSTRACT

Owing to its biotoxicity and inductive effect on photochemical pollution, atmospheric peroxyacetyl nitrate (PAN), which is a typical product of atmospheric photochemical reactions, has attracted much research attention. However, to the best of our knowledge, few comprehensive studies have been conducted on the seasonal variation and key influencing factors of PAN concentrations in southern China. In this study, PAN, ozone (O3), precursor volatile organic compound (VOC), and other pollutant concentrations were measured online for 1 year (from October 2021 to September 2022) in Shenzhen, a megacity in the Greater Bay Area of China. The average concentrations of PAN and peroxypropionyl nitrate (PPN) were 0.54 and 0.08 parts per billion (ppb), and the maximum hourly concentrations reached 10.32 and 1.01 ppb, respectively. The results of the generalized additive model (GAM) showed that the atmospheric oxidation capacity and precursor concentration were the most important factors affecting the PAN concentration. According to the steady-state model, the average cumulative contribution to the peroxyacetyl (PA) radical formation rate by six major carbonyl compounds was calculated at 4.2 × 106 molecules cm-3 s-1, and acetaldehyde (63.0 %) and acetone (13.9 %) contributed the most. Furthermore, the photochemical-age-based parameterization method was used to analyze the source contributions of carbonyl compounds and PA radicals. The results showed that although the primary anthropogenic (40.2 %), biogenic (27.8 %), and secondary anthropogenic (16.4 %) sources were the most important contributors of PA radicals, the biogenic and secondary anthropogenic source contributions both increased considerably in summer, and the cumulative proportion of both sources reached ~70 % in July. In addition, a comparison of PAN pollution processes in different seasons revealed that in summer and winter, the PAN concentration was predominantly limited by precursors and meteorological parameters, such as light intensity, respectively.


Subject(s)
Air Pollutants , Ozone , Volatile Organic Compounds , Seasons , Air Pollutants/analysis , China , Ozone/analysis , Volatile Organic Compounds/analysis , Environmental Monitoring
7.
Environ Pollut ; 324: 121380, 2023 May 01.
Article in English | MEDLINE | ID: mdl-36863439

ABSTRACT

The mixing of black carbon (BC) with secondary materials is a major uncertainty source in assessing its radiative forcing. However, current understanding of the formation and evolution of various BC components is limited, particularly in the Pearl River Delta, China. This study measured submicron BC-associated nonrefractory materials and the total submicron nonrefractory materials using a soot particle aerosol mass spectrometer and a high-resolution time-of-flight aerosol mass spectrometer, respectively, at a coastal site in Shenzhen, China. Two distinct atmospheric conditions were also identified to further explore the distinctive evolution of BC-associated components: polluted period (PP) and clean period (CP). Comparing the components of two particles, we found that more-oxidized organic factor (MO-OOA) prefers to form on BC during PP rather CP. The formation of MO-OOA on BC (MO-OOABC) was affected by both enhanced photochemical processes and nocturnal heterogeneous processes. Enhanced photo-reactivity of BC, photochemistry during the daytime, and heterogeneous reaction at nighttime were potential pathways for MO-OOABC formation during PP. The fresh BC surface was favorable for the formation of MO-OOABC. Our study shows the evolution of BC-associated components under different atmospheric conditions, which should be considered in regional climate models to improve the assessment of the climate effects of BC.


Subject(s)
Air Pollutants , Air Pollutants/analysis , Soot/analysis , Rivers , China , Aerosols/analysis , Carbon/analysis
8.
Inorg Chem ; 62(7): 3297-3304, 2023 Feb 20.
Article in English | MEDLINE | ID: mdl-36758163

ABSTRACT

Remodeling the active surface through fabricating heterostructures can substantially enhance alkaline water electrolysis driven by renewable electrical energy. However, there are still great challenges in the synthesis of highly reactive and robust heterostructures to achieve both ampere-level current density hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Herein, we report a new Co/CeO2 heterojunction self-supported electrode for sustainable overall water splitting. The self-supporting Co/CeO2 heterostructures required only low overpotentials of 31.9 ± 2.2, 253.3 ± 2.7, and 316.7 ± 3 mV for HER and 214.1 ± 1.4, 362.3 ± 1.9, and 400.3 ± 3.7 mV for OER at 0.01, 0.5, and 1.0 A·cm-2, respectively, being one of the best Co-based bifunctional electrodes. Electrolyzer constructed from this electrode acting as an anode and cathode merely required cell voltages of 1.92 ± 0.02 V at 1.0 A·cm-2 for overall water splitting. Multiple characterization techniques combined with density functional theory calculations disclosed the different active sites on the anode and cathode, and the charge redistributions on the heterointerfaces that can optimize the adsorption of H and oxygen-containing intermediates, respectively. This study presents the tremendous prospective of self-supporting heterostructures for effective and economical overall water splitting.

9.
World J Clin Cases ; 11(2): 464-471, 2023 Jan 16.
Article in English | MEDLINE | ID: mdl-36686343

ABSTRACT

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccinations have been administered worldwide, with occasional reports of associated neurological complications. Specifically, the impact of vaccinations on individuals with X-linked Charcot-Marie-Tooth disease type 1 (CMTX1) is unclear. Patients with CMTX1 can have stroke-like episodes with posterior reversible encephalopathy syndrome on magnetic resonance imaging (MRI), although this is rare. CASE SUMMARY: A 39-year-old man was admitted with episodic aphasia and dysphagia for 2 d. He received SARS-CoV-2 vaccination 39 d before admission. Physical examination showed pes cavus and reduced tendon reflexes. Brain MRI showed bilateral, symmetrical, restricted diffusion with T2 hyperintensities in the cerebral hemispheres. Nerve conduction studies revealed peripheral nerve damage. He was diagnosed with Charcot-Marie-Tooth disease, and a hemizygous mutation in the GJB1 gene on the X chromosome, known to be pathogenic for CMTX1, was identified. Initially, we suspected transient ischemic attack or demyelinating leukoencephalopathy. We initiated treatment with antithrombotic therapy and immunotherapy. At 1.5 mo after discharge, brain MRI showed complete resolution of lesions, with no recurrence. CONCLUSION: SARS-CoV-2 vaccination could be a predisposing factor for CMTX1 and trigger a sudden presentation.

10.
J Am Chem Soc ; 145(2): 1144-1154, 2023 01 18.
Article in English | MEDLINE | ID: mdl-36538569

ABSTRACT

Remolding the reactivity of metal active sites is critical to facilitate renewable electricity-powered water electrolysis. Doping heteroatoms, such as Se, into a metal crystal lattice has been considered an effective approach, yet usually suffers from loss of functional heteroatoms during harsh electrocatalytic conditions, thus leading to the gradual inactivation of the catalysts. Here, we report a new heteroatom-containing molecule-enhanced strategy toward sustainable oxygen evolution improvement. An organoselenium ligand, bis(3,5-dimethyl-1H-pyrazol-4-yl)selenide containing robust C-Se-C covalent bonds equipped in the precatalyst of ultrathin metal-organic nanosheets Co-SeMON, is revealed to significantly enhance the catalytic mass activity of the cobalt site by 25 times, as well as extend the catalyst operation time in alkaline conditions by 1 or 2 orders of magnitude compared with these reported metal selenides. A combination of various in situ/ex situ spectroscopic techniques, ab initio molecular dynamics, and density functional theory calculations unveiled the organoselenium intensified mechanism, in which the nonclassical bonding of Se to O-containing intermediates endows adsorption-energy regulation beyond the conventional scaling relationship. Our results showcase the great potential of molecule-enhanced catalysts for highly efficient and economical water oxidation.


Subject(s)
Cobalt , Metals , Adsorption , Oxygen , Water
11.
Sci Total Environ ; 859(Pt 1): 160290, 2023 Feb 10.
Article in English | MEDLINE | ID: mdl-36410489

ABSTRACT

Refractory black carbon (rBC) aerosols emitted from incomplete combustion are important climate forcers. Understanding the chemical characteristics and evolution of rBC-related components is particularly crucial to assess rBC environmental impacts. Here, we explored the chemical components of rBC in Shenzhen, China, using a soot-particle aerosol mass spectrometer (SP-AMS). The observations showed that the rBC coating was mainly composed of secondary aerosols with an average mass contribution of 84.7 %. Among them, secondary organic coating occupied ∼57.7 % of the total coating mass. Exploration of the relationship between secondary organic aerosol (SOA) coating and Ox (=NO2 + O3, an indicator of the extent of photochemical processing) showed that SOA coating was generated mainly through photochemical oxidation during the day. Similarly, sulfate coating, with a small mass fraction of 0.9 %, was also dominated by photochemical oxidation. In contrast, nitrate coating responded positively to ambient relative humidity, especially at night, indicating that it was driven by heterogeneous reactions. In addition, the increased ratio of nitrate on rBC to bulk nitrate at night suggested that black carbon surface could facilitate nocturnal nitrate formation.


Subject(s)
Air Pollutants , Air Pollutants/analysis , Nitrates , Aerosols/analysis , Soot/analysis , Organic Chemicals/analysis , China , Carbon/analysis , Particulate Matter/analysis
12.
Plant Sci ; 324: 111446, 2022 Nov.
Article in English | MEDLINE | ID: mdl-36041562

ABSTRACT

Heading date is crucial for rice reproduction and the geographical expansion of cultivation. We fine-mapped qHD5 and identified LOC_Os05g03040, a gene that encodes an AP2 transcription factor, as the candidate gene of qHD5 in our previous study. In this article, using two near-isogenic lines NIL(BG1) and NIL(XLJ), which were derived from the progeny of the cross between BigGrain1 (BG1) and Xiaolijing (XLJ), we verified that LOC_Os05g03040 represses heading date in rice through genetic complementation and CRISPR/Cas9 gene-editing experiments. Complementary results showed that qHD5 is a semi-dominant gene and that the qHD5XLJ and qHD5BG1 alleles are both functional. The homozygous mutant line generated from knocking out qHD5XLJ in NIL(XLJ) headed earlier than NIL(XLJ) under both short-day and long-day conditions. In addition, the homozygous mutant line of qHD5BG1 in NIL(BG1) also headed slightly earlier than NIL(BG1). All of these results show that qHD5 represses the heading date in rice. Transient expression showed that the qHD5 protein localizes to the nucleus. Transactivation activity assays showed that the C-terminus is the critical site that affects self-activation in qHD5XLJ. qRT-PCR analysis revealed that qHD5 represses flowering by down-regulating Ehd2. qHD5 may have been selected during indica rice domestication.


Subject(s)
Oryza , Alleles , Chromosome Mapping , Gene Expression Regulation, Plant , Oryza/metabolism , Quantitative Trait Loci , Transcription Factors/genetics , Transcription Factors/metabolism
13.
Chem Sci ; 13(6): 1569-1593, 2022 Feb 09.
Article in English | MEDLINE | ID: mdl-35282621

ABSTRACT

A balance between activity and stability is greatly challenging in designing efficient metal nanoparticles (MNPs) for heterogeneous catalysis. Generally, reducing the size of MNPs to the atomic scale can provide high atom utilization, abundant active sites, and special electronic/band structures, for vastly enhancing their catalytic activity. Nevertheless, due to the dramatically increased surface free energy, such ultrafine nanostructures often suffer from severe aggregation and/or structural degradation during synthesis and catalysis, greatly weakening their reactivities, selectivities and stabilities. Porous molecule-based materials (PMMs), mainly including metal-organic frameworks (MOFs), covalent organic frameworks (COFs) and porous organic polymers (POPs) or cages (POCs), exhibit high specific surface areas, high porosity, and tunable molecular confined space, being promising carriers or precursors to construct ultrafine nanostructures. The confinement effects of their nano/sub-nanopores or specific binding sites can not only effectively limit the agglomeration and growth of MNPs during reduction or pyrolysis processes, but also stabilize the resultant ultrafine nanostructures and modulate their electronic structures and stereochemistry in catalysis. In this review, we highlight the latest advancements in the confinement synthesis in PMMs for constructing atomic-scale nanostructures, such as ultrafine MNPs, nanoclusters, and single atoms. Firstly, we illustrated the typical confinement methods for synthesis. Secondly, we discussed different confinement strategies, including PMM-confinement strategy and PMM-confinement pyrolysis strategy, for synthesizing ultrafine nanostructures. Finally, we put forward the challenges and new opportunities for further applications of confinement synthesis in PMMs.

14.
World J Clin Cases ; 10(4): 1447-1453, 2022 Feb 06.
Article in English | MEDLINE | ID: mdl-35211582

ABSTRACT

BACKGROUND: Bleeding from gastroesophageal varices (GOV) is a serious complication in patients with liver cirrhosis, carrying a very high mortality rate. For secondary prophylaxis against initial and recurrent bleeding, endoscopic therapy is a critical intervention. Endoscopic variceal clipping for secondary prophylaxis in adult GOV has not been reported. CASE SUMMARY: A 66-year-old man with cirrhosis was admitted to our hospital complaining of asthenia and hematochezia for 1 wk. His hemoglobin level and red blood cell counts were significantly decreased, and his fecal occult blood test was positive. An enhanced computed tomography of the abdomen showed GOV. The patient was diagnosed with hepatitis B cirrhosis-related GOV bleeding. A series of palliative treatments were administered, resulting in significant clinical improvement. Subsequently, an endoscopic examination revealed severe gastric fundal varices, prompting endoscopic variceal clipping. There were no further episodes of gastrointestinal bleeding. The GOV improved significantly on follow-up imaging and was confirmed as improved on endoscopy at the 5th postoperative month. CONCLUSION: Our results suggest that endoscopic clipping is an inexpensive, safe, easy, effective, and tolerable method for the secondary prophylaxis of bleeding from gastric type 2 GOV. However, additional research is indicated to confirm its long-term safety and efficacy.

15.
World J Clin Cases ; 10(5): 1580-1585, 2022 Feb 16.
Article in English | MEDLINE | ID: mdl-35211595

ABSTRACT

BACKGROUND: Cytokine release syndrome (CRS) is defined as systemic inflammation that usually occurs following chimeric antigen receptor T-cell therapy administration; however, it has not been reported in patients with untreated non-small cell lung cancer to date. CASE SUMMARY: A 44-year-old nonsmoking woman presented to the hospital due to fever, palpitation, nausea, and cough for 1 mo and was diagnosed with stage cT3N3M0 (IIIc) adenocarcinoma of the lung. Auxiliary examinations revealed elevated cytokine [tumor necrosis factor-α, interleukin (IL)-1ß, and IL-6] and inflammatory factor levels, which decreased after treatment with corticosteroids and immunoglobulin and when tumor growth was controlled following chemotherapy, radiotherapy, and antiangiogenesis therapy. However, tumor recurrence was observed. After administration of nivolumab as third-line treatment, the patient's condition was transiently controlled; however, CRS-like symptoms suddenly emerged, which led to a resurgence of cytokines and inflammatory factors and rapid death. CONCLUSION: CRS can develop in treatment-naïve lung cancer patients. Patients with tumor-related CRS may be at risk of CRS recurrence, aggravation, and onset of immune checkpoint inhibitor-related adverse events.

16.
Environ Pollut ; 301: 119027, 2022 May 15.
Article in English | MEDLINE | ID: mdl-35183665

ABSTRACT

During the COVID-19 lockdown, atmospheric PM2.5 in the Pearl River Delta (PRD) showed the highest reduction in China, but the reasons, being a critical question for future air quality policy design, are not yet clear. In this study, we analyzed the relationships among gaseous precursors, secondary aerosols and atmospheric oxidation capacity in Shenzhen, a megacity in the PRD, during the lockdown period in 2020 and the same period in 2021. The comprehensive observational datasets showed large lockdown declines in all primary and secondary pollutants (including O3). We found that, however, the daytime concentrations of secondary aerosols during the lockdown period and normal period were rather similar when the corresponding odd oxygen (Ox≡O3+NO2, an indicator of photochemical processing avoiding the titration effect of O3 by freshly emitted NO) were at similar levels. Therefore, reduced Ox, rather than the large reduction in precursors, was a direct driver to achieve the decline in secondary aerosols. Moreover, Ox was also found to determine the spatial distribution of intercity PM2.5 levels in winter PRD. Thus, an effective strategy for winter PM2.5 mitigation should emphasize on control of winter O3 formation in the PRD and other regions with similar conditions.


Subject(s)
Air Pollutants , Air Pollution , COVID-19 , Ozone , Air Pollutants/analysis , Air Pollution/analysis , China , Communicable Disease Control , Environmental Monitoring , Humans , Ozone/analysis , Particulate Matter/analysis
17.
Environ Pollut ; 298: 118840, 2022 Apr 01.
Article in English | MEDLINE | ID: mdl-35026325

ABSTRACT

The role of coarse particles has recently been proven to be underestimated in the atmosphere and can strongly influence clouds, ecosystems and climate. However, previous studies on atmospheric chemistry of volatile organic compounds (VOCs) have mostly focused on the products in fine particles, it remains less understood how coarse particles promote secondary organic aerosol (SOA) formation. In this study, we investigated water-soluble compounds of size-segregated aerosol samples (0.056 to >18 µm) collected at a coastal rural site in southern China during late summer and found that oxygenated organic matter was abundant in the coarse mode. Comprehensive source apportionment based on mass spectrum and 14C analysis indicated that different from fossil fuel SOA, biogenic SOA existed more in the coarse mode than in the fine mode. The SOA in the coarse mode showed a unique correlation with biogenic VOCs. 13C and elemental composition strongly suggested a pathway of heterogeneous reactions on coarse particles, which had an abundant low-acidic aqueous environment with soil dust to possibly initiate iron-catalytic oxidation reactions to form SOA. This potential pathway might complement understanding of both formation of biogenic SOA and sink of biogenic VOCs in global biogeochemical cycles, warrantying future relevant studies.


Subject(s)
Air Pollutants , Volatile Organic Compounds , Aerosols/analysis , Air Pollutants/analysis , Dust , Ecosystem , Soil , Volatile Organic Compounds/analysis
18.
Front Pediatr ; 9: 727411, 2021.
Article in English | MEDLINE | ID: mdl-34660488

ABSTRACT

Background: Kikuchi-Fujimoto disease (KFD) is a benign and self-limiting disease characterized by regional lymphadenitis and low-grade fever. Encephalopathy may present in children with KFD. We present three cases of KFD with encephalopathy in children and a literature review. Methods: Literature published between 2010 and 2020 was reviewed to understand the clinical features, laboratory findings, and treatments for encephalopathy occurring in children with KFD. Results: The interval between KFD and onset of neurological symptoms was 10 days to 3 months. Laboratory results were normal, except for high protein levels in cerebrospinal fluid findings. Brain magnetic resonance imaging (MRI) findings include hyperintense T2 and FLAIR signal in the supratentorial white matter, deep gray matter, brain stem, cerebellum, temporal lobes, pons, and basal ganglia. Glucocorticoids and immunoglobulin could be effective for treating KFD with encephalopathy. Conclusion: The early clinical manifestations of KFD with encephalopathy in children lack specificity, and the diagnosis is mainly based on CSF analysis and brain MRI findings. Early and timely immunomodulatory therapy is effective and can improve the prognosis of patients with KFD with encephalopathy.

19.
Environ Sci Technol ; 55(17): 11557-11567, 2021 Sep 07.
Article in English | MEDLINE | ID: mdl-34431667

ABSTRACT

The lockdown due to COVID-19 created a rare opportunity to examine the nonlinear responses of secondary aerosols, which are formed through atmospheric oxidation of gaseous precursors, to intensive precursor emission reductions. Based on unique observational data sets from six supersites in eastern China during 2019-2021, we found that the lockdown caused considerable decreases (32-61%) in different secondary aerosol components in the study region because of similar-degree precursor reductions. However, due to insufficient combustion-related volatile organic compound (VOC) reduction, odd oxygen (Ox = O3 + NO2) concentration, an indicator of the extent of photochemical processing, showed little change and did not promote more decreases in secondary aerosols. We also found that the Chinese provinces and international cities that experienced reduced Ox during the lockdown usually gained a greater simultaneous PM2.5 decrease than other provinces and cities with an increased Ox. Therefore, we argue that strict VOC control in winter, which has been largely ignored so far, is critical in future policies to mitigate winter haze more efficiently by reducing Ox simultaneously.


Subject(s)
Air Pollutants , Air Pollution , COVID-19 , Aerosols/analysis , Air Pollutants/analysis , Air Pollution/analysis , Air Pollution/prevention & control , China , Communicable Disease Control , Environmental Monitoring , Humans , Oxygen , Particulate Matter/analysis , SARS-CoV-2
20.
Chem Commun (Camb) ; 57(59): 7292-7295, 2021 Jul 28.
Article in English | MEDLINE | ID: mdl-34213519

ABSTRACT

By utilizing a supramolecular complex rather than an individual molecule as a deformable and elastic substitutional component, we put forward a solid-solution strategy and demonstrate an example of how two related yet non-isostructural crystalline host-guest compounds can form molecular solid solutions. Interestingly, such a strategy can effectively and continuously modulate the molecular motion and phase transition in them, as revealed by the variable-temperature/frequency dielectric responses.

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