Reversible Stacking and Delamination-Regulation of MXene via Controlled Freezing.

MXene's configuration, whether it is aggregated or dispersed in a monolayer, determines the specific application areas and even greatly influences the intrinsic properties of MXene. However, how to desirably control MXene's configuration is challenging. Here, a simple, additive-free, chemical reaction-free, and scalable strategy to optionally and reversibly regulate MXene's ordered stacking and delamination of MXene aggregates (AM) is reported. Just by controlled freezing of MXene aqueous dispersions, the aggregation percentage, delamination percentage, and interlayer spacing of AM can be finely tuned. Experimental results reveal that the freezing-induced aggregation and delamination effects can be explained by the squeezing action of growing ice grains on the MXene excluded/concentrated between ice grains and the expanding action caused by the ice formation between AM lamellae, respectively. The dominance between them depends on the freezing parameter-influenced ice nucleation sites, numbers, and ice grain sizes. This work not only contributes to the preparation, storage, and practical applications of MXene, but also opens a new and green avenue for controlling materials' assembly structures.

Reference panel-guided super-resolution inference of Hi-C data.

MOTIVATION: Accurately assessing contacts between DNA fragments inside the nucleus with Hi-C experiment is crucial for understanding the role of 3D genome organization in gene regulation. This challenging task is due in part to the high sequencing depth of Hi-C libraries required to support high-resolution analyses. Most existing Hi-C data are collected with limited sequencing coverage, leading to poor chromatin interaction frequency estimation. Current computational approaches to enhance Hi-C signals focus on the analysis of individual Hi-C datasets of interest, without taking advantage of the facts that (i) several hundred Hi-C contact maps are publicly available and (ii) the vast majority of local spatial organizations are conserved across multiple cell types. RESULTS: Here, we present RefHiC-SR, an attention-based deep learning framework that uses a reference panel of Hi-C datasets to facilitate the enhancement of Hi-C data resolution of a given study sample. We compare RefHiC-SR against tools that do not use reference samples and find that RefHiC-SR outperforms other programs across different cell types, and sequencing depths. It also enables high-accuracy mapping of structures such as loops and topologically associating domains. AVAILABILITY AND IMPLEMENTATION: https://github.com/BlanchetteLab/RefHiC.

Fossil and Nonfossil Sources of Winter Organic Aerosols in the Regional Background Atmosphere of China.

Carbonaceous aerosols (CA) from anthropogenic emissions have been significantly reduced in urban China in recent years. However, the relative contributions of fossil and nonfossil sources to CA in rural and background regions of China remain unclear. In this study, the sources of different carbonaceous fractions in fine aerosols (PM2.5) from five background sites of the China Meteorological Administration Atmosphere Watch Network during the winter of 2019 and 2020 were quantified using radiocarbon (14C) and organic markers. The results showed that nonfossil sources contributed 44-69% to total carbon at these five background sites. Fossil fuel combustion was the predominant source of elemental carbon at all sites (73 ± 12%). Nonfossil sources dominated organic carbon (OC) in these background regions (61 ± 13%), with biomass burning or biogenic-derived secondary organic carbon (SOC) as the most important contributors. However, the relative fossil fuel source to OC in China (39 ± 13%) still exceeds those at other regional/background sites in Asia, Europe, and the USA. SOC dominated the fossil fuel-derived OC, highlighting the impact of regional transport from anthropogenic sources on background aerosol levels. It is therefore imperative to develop and implement aerosol reduction policies and technologies tailored to both the anthropogenic and biogenic emissions to mitigate the environmental and health risks of aerosol pollution across China.

A case of excisionally remitted indolent NK-cell enteropathy in the oral cavity and a mini-review.

Benign natural killer cell enteropathy (NKCE) was first identified in the gastrointestinal (GI) tract. Notably, instances of NKCE have previously been observed at various sites other than the GI tract, including the gallbladder, lymph nodes, esophagus, and female genital tract. Typical NKCE manifests as an NK-cell immunohistological phenotype, with or without TCR rearrangement, and is characterized by the absence of Epstein-Barr virus (EBV) infection and protracted clinical progression. The misdiagnosis of NKT-cell lymphoma has resulted in some patients receiving chemotherapy, while in other instances, the patients' conditions resolved without treatment and showed no evidence of disease recurrence or progression during follow-up examinations. In this paper, we describe a unique case of EBV-negative NKCE occurring in the oral cavity, the first time such a case has been documented. The tumor completely resolved after an excisional biopsy, and subsequent follow-up did not reveal any signs of disease recurrence.

Nucleic acid aptamer-based electrochemical sensor for the detection of serum P-tau231 and the instant screening test of Alzheimer's disease.

The instant screening of patients with a tendency towards developing Alzheimer's disease (AD) is significant for providing preventive measures and treatment. However, the current imaging-based technology cannot meet the requirements in the early stage. Developing biosensor-based liquid biopsy technology could be overcoming this bottleneck problem. Herein, we developed a simple, low-cost, and sensitive electrochemical aptamer biosensor for detecting phosphorylated tau protein threonine 231 (P-tau231), the earliest and one of the most efficacious abnormally elevated biomarkers of AD. Gold nanoparticles (AuNPs) were electrochemically synthesized on a glassy carbon electrode as the transducer, exhibiting excellent conductivity, and were applied to amplify the electrochemical signal. A nucleic acid aptamer was designed as the receptor to capture the P-tau231 protein, specifically through the formation of an aptamer-antigen complex. The proposed biosensor showed excellent sensitivity in detecting P-tau 231, with a broad linear detection range from 10 to 107 pg/mL and a limit of detection (LOD) of 2.31 pg/mL. The recoveries of the biosensor in human serum ranged from 97.59 to 103.26%, demonstrating that the biosensor could be used in complex practical samples. In addition, the results showed that the developed biosensor has good repeatability, reproducibility, and stability, which provides a novel method for the early screening of AD.

CAMBA framework: Unveiling the brain asymmetry alterations and longitudinal changes after stroke using resting-state EEG.

Hemispheric asymmetry or lateralization is a fundamental principle of brain organization. However, it is poorly understood to what extent the brain asymmetries across different levels of functional organizations are evident in health or altered in brain diseases. Here, we propose a framework that integrates three degrees of brain interactions (isolated nodes, node-node, and edge-edge) into a unified analysis pipeline to capture the sliding window-based asymmetry dynamics at both the node and hemisphere levels. We apply this framework to resting-state EEG in healthy and stroke populations and investigate the stroke-induced abnormal alterations in brain asymmetries and longitudinal asymmetry changes during poststroke rehabilitation. We observe that the mean asymmetry in patients was abnormally enhanced across different frequency bands and levels of brain interactions, with these abnormal patterns strongly associated with the side of the stroke lesion. Compared to healthy controls, patients displayed significant alterations in asymmetry fluctuations, disrupting and reconfiguring the balance of inter-hemispheric integration and segregation. Additionally, analyses reveal that specific abnormal asymmetry metrics in patients tend to move towards those observed in healthy controls after short-term brain-computer interface rehabilitation. Furthermore, preliminary evidence suggests that baseline clinical and asymmetry features can predict poststroke improvements in the Fugl-Meyer assessment of the lower extremity (mean absolute error of about 2). Overall, these findings advance our understanding of hemispheric asymmetry. Our framework offers new insights into the mechanisms underlying brain alterations and recovery after a brain lesion, may help identify prognostic biomarkers, and can be easily extended to different functional modalities.

Immunotherapies for the Effective Treatment of Primary Autoimmune Cerebellar Ataxia: a Case Series.

Primary autoimmune cerebellar ataxia (PACA) is an idiopathic sporadic cerebellar ataxia that is thought to be immune-mediated but lacks biomarkers or a known cause. Here, we report two cases of immune-mediated cerebellar ataxia that responded favorably to immunotherapy, in which tissue-based indirect immunofluorescence test for serum or cerebrospinal fluid (CSF) samples yielded positive results. Case 1 was a 78-year-old man who presented with subacute progressive gait ataxia with truncal instability and dysarthria in response to steroids. Case 2 was a 62-year-old man who presented with relapses and remissions of acute progressive cerebellar ataxia occurring 1-2 times per year. Despite a favorable response to steroid treatment, he relapsed repeatedly in the absence of long-term immunosuppression. In the case of "idiopathic" cerebellar ataxia, immune-mediated causes should be investigated, and immunotherapy may have therapeutic effects.

Ultrafine FeF3·0.33H2O Nanocrystal-Doped Graphene Aerogel Cathode Materials for Advanced Lithium-Ion Batteries.

FeF3 has been extensively studied as an alternative positive material owing to its superior specific capacity and low cost, but the low conductivity, large volume variation, and slow kinetics seriously hinder its commercialization. Here, we propose the in situ growth of ultrafine FeF3·0.33H2O NPs on a three-dimensional reduced graphene oxide (3D RGO) aerogel with abundant pores by a facile freeze drying process followed by thermal annealing and fluorination. Within the FeF3·0.33H2O/RGO composites, the three-dimensional (3D) RGO aerogel and hierarchical porous structure ensure rapid diffusion of electrons/ions within the cathode, enabling good reversibility of FeF3. Benefiting from these advantages, a superior cycle behavior of 232 mAh g-1 under 0.1C over 100 cycles as well as outstanding rate performance is achieved. These results provide a promising approach for advanced cathode materials for Li-ion batteries.

Increasing Nonfossil Fuel Contributions to Atmospheric Nitrate in Urban China from Observation to Prediction.

China's nitrogen oxide (NOx) emissions have undergone significant changes over the past few decades. However, nonfossil fuel NOx emissions are not yet well constrained in urban environments, resulting in a substantial underestimation of their importance relative to the known fossil fuel NOx emissions. We developed an approach using machine learning that is accurate enough to generate a long time series of the nitrogen isotopic composition (δ15N) of atmospheric nitrate using high-level accuracies of air pollutants and meteorology data. Air temperature was found to be the critical driver of the variation of nitrate δ15N at daily resolution based on this approach, while significant reductions of aerosol and its precursor emissions played a key role in the change of nitrate δ15N on the yearly scale. Predictions from this model found a significant decrease in nitrate δ15N in Chinese megacities (Beijing and Guangzhou as representative cities in the north and south, respectively) since 2013, implying an enhanced contribution of nonfossil fuel NOx emissions to nitrate aerosols (up to 22%-26% in 2021 from 18%-22% in 2013 quantified by an isotope mixing model), as confirmed by the Weather Research and Forecasting model coupled with online chemistry (WRF-Chem) simulation. Meanwhile, the declining contribution in coal combustion (34%-39% in 2013 to 31%-34% in 2021) and increasing contribution of natural gas combustion (11%-14% in 2013 to 14%-17% in 2021) demonstrated the transformation of China's energy structure from coal to natural gas. This approach provides missing records for exploring long-term variability in the nitrogen isotope system and may contribute to the study of the global reactive nitrogen biogeochemical cycle.

Wildfire-Derived Nitrogen Aerosols Threaten the Fragile Ecosystem in Himalayas and Tibetan Plateau.

Himalayas and Tibetan Plateau (HTP) is important for global biodiversity and regional sustainable development. While numerous studies have revealed that the ecosystem in this unique and pristine region is changing, their exact causes are still poorly understood. Here, we present a year-round (23 March 2017 to 19 March 2018) ground- and satellite-based atmospheric observation at the Qomolangma monitoring station (QOMS, 4276 m a.s.l.). Based on a comprehensive chemical and stable isotope (15N) analysis of nitrogen compounds and satellite observations, we provide unequivocal evidence that wildfire emissions in South Asia can come across the Himalayas and threaten the HTP's ecosystem. Such wildfire episodes, mostly occurring in spring (March-April), not only substantially enhanced the aerosol nitrogen concentration but also altered its composition (i.e., rendering it more bioavailable). We estimated a nitrogen deposition flux at QOMS of ∼10 kg N ha-1 yr-1, which is approximately twice the lower value of the critical load range reported for the Alpine ecosystem. Such adverse impact is particularly concerning, given the anticipated increase of wildfire activities in the future under climate change.

Hederacoside C ameliorates colitis via restoring impaired intestinal barrier through moderating S100A9/MAPK and neutrophil recruitment inactivation.

Hederacoside C (HSC) has attracted much attention as a novel modulator of inflammation, but its anti-inflammatory mechanism remains elusive. In the present study, we investigated how HSC attenuated intestinal inflammation in vivo and in vitro. HSC injection significantly alleviated TNBS-induced colitis by inhibiting pro-inflammatory cytokine production and colonic epithelial cell apoptosis, and partially restored colonic epithelial cell proliferation. The therapeutic effect of HSC injection was comparable to that of oral administration of mesalazine (200 mg·kg-1·d-1, i.g.). In LPS-stimulated human intestinal epithelial Caco-2 cells, pretreatment with HSC (0.1, 1, 10 µM) significantly inhibited activation of MAPK/NF-κB and its downstream signaling pathways. Pretreatment with HSC prevented LPS-induced TLR4 dimerization and MyD88 recruitment in vitro. Quantitative proteomic analysis revealed that HSC injection regulated 18 proteins in the colon samples, mainly clustered in neutrophil degranulation. Among them, S100A9 involved in the degranulation of neutrophils was one of the most significantly down-regulated proteins. HSC suppressed the expression of S100A9 and its downstream genes including TLR4, MAPK, and NF-κB axes in colon. In Caco-2 cells, recombinant S100A9 protein activated the MAPK/NF-κB signaling pathway and induced inflammation, which were ameliorated by pretreatment with HSC. Notably, HSC attenuated neutrophil recruitment and degranulation as well as S100A9 release in vitro and in vivo. In addition, HSC promoted the expression of tight junction proteins and repaired the epithelial barrier via inhibiting S100A9. Our results verify that HSC ameliorates colitis via restoring impaired intestinal barrier through moderating S100A9/MAPK and neutrophil recruitment inactivation, suggesting that HSC is a promising therapeutic candidate for colitis.

Superior photo-Fenton degradation of acetamiprid by α- Fe2O3-pillared bentonite/L-cysteine complex: Synergy of L-cysteine and visible light.

Acetamiprid is a potential threat to human health, aquatic life, soil microorganisms and beneficial insects as a recalcitrant pollutant in wastewater treatment plant effluents. In this work, the synthesized α-Fe2O3-pillared bentonite (FPB) was used to degrade acetamiprid in the photo-Fenton process with the assistance of L-cysteine (L-cys) existing in natural aquatic environment. The kinetic constant k of acetamiprid degradation by FPB/L-cys in the photo-Fenton process was far more than that in the Fenton process of FPB/L-cys lacking light and the photo-Fenton process of FPB without L-cys. The positive linear correlation between k and ≡Fe(II) content indicated the synergy of L-cys and visible light accelerated the cycle of Fe(III) to Fe(II) in FPB/L-cys during the degradation of acetamiprid by elevating the visible light response of FPB, and promoting the interfacial electron transfer from the active sites of FPB to hydrogen peroxide and photo-generated electron transfer from conduction band of α-Fe2O3 to the active sites of FPB. The boosting •OH and 1O2 were predominantly responsible for acetamiprid degradation. Acetamiprid could be efficiently degraded into less toxic small molecules in the photo-Fenton process via C-N bond breaking, hydroxylation, demethylation, ketonization, dechlorination, and ring cleavage.

Controllable Synthesis, Photocatalytic Property, and Mechanism of a Novel POM-Based Direct Z-Scheme Nano-Heterojunction α-Fe2O3/P2Mo18.

In order to improve photocatalytic activity and maximize solar energy use, a new composite material Fe2O3/P2Mo18 was prepared by combining polyoxometalates (P2Mo18) with Fe2O3 nanosheets. FT-IR, XRD, XPS, SEM, TEM, UV-vis, EIS, and PL were used to characterize the composite material, and nano-Fe2O3 of different sizes and morphologies with a controllable absorption range was prepared by adjusting the reaction time, and, when combined with P2Mo18, a composite photocatalyst with efficient visible light response and photocatalytic activity was constructed. The EIS, Bode, and PL spectra analysis results show that the Fe2O3/P2Mo18 composite material has outstanding interfacial charge transfer efficiency and potential photocatalytic application possibilities. Model reactions of methylene blue (MB) and Cr (VI) photodegradation were used to evaluate the redox activity of Fe2O3/P2Mo18 composites under simulated visible light. The photocatalytic degradation rate was as high as 98.98% for MB and 96.86% for Cr (VI) when the composite ratio was Fe2O3/P2Mo18-5%. This research opens up a new avenue for the development of high-performance photocatalysts.

Recent Progress in Atmospheric Chemistry Research in China: Establishing a Theoretical Framework for the "Air Pollution Complex".

Atmospheric chemistry research has been growing rapidly in China in the last 25 years since the concept of the "air pollution complex" was first proposed by Professor Xiaoyan TANG in 1997. For papers published in 2021 on air pollution (only papers included in the Web of Science Core Collection database were considered), more than 24 000 papers were authored or co-authored by scientists working in China. In this paper, we review a limited number of representative and significant studies on atmospheric chemistry in China in the last few years, including studies on (1) sources and emission inventories, (2) atmospheric chemical processes, (3) interactions of air pollution with meteorology, weather and climate, (4) interactions between the biosphere and atmosphere, and (5) data assimilation. The intention was not to provide a complete review of all progress made in the last few years, but rather to serve as a starting point for learning more about atmospheric chemistry research in China. The advances reviewed in this paper have enabled a theoretical framework for the air pollution complex to be established, provided robust scientific support to highly successful air pollution control policies in China, and created great opportunities in education, training, and career development for many graduate students and young scientists. This paper further highlights that developing and low-income countries that are heavily affected by air pollution can benefit from these research advances, whilst at the same time acknowledging that many challenges and opportunities still remain in atmospheric chemistry research in China, to hopefully be addressed over the next few decades.

[Abnormal Activation of T Cells in HIV-1 Infection After Antiretroviral Therapy].

Objective: To investigate the relationship between abnormal activation of T cell subsets in peripheral whole blood and the recovery of immune function in persons infected with HIV-1, and to examine the relationship between the size of the viral reservoir of HIV-1 DNA and T cell subsets. Methods: HIV-1-infected persons who underwent routine testing between July 2019 and May 2020 were the target population of the study. According to whether, at the time of enrollment, their CD4+ T cells reached 500 cells/µL after antiretroviral therapy (ART), HIV-1-infected persons were divided into two groups, 76 in the deficiency group and 61 in the immune recovery group. In addition, 22 people who were not exposed to HIV-1, and who were tested negative for HIV-1 antibody were selected as the control group. For the three groups of subjects, tests of the T cell subsets were conducted. A total of 77 HIV-1-infected persons, with 44 from the deficiency group and 33 from the recovery group, were examined for HIV-1 DNA reservoir. The deficiency group and the recovery group were followed up 6 months later and the CD4+ T cell test results of 133 blood samples were collected, with 74 from the deficiency group and 59 from the recovery group. Results: The proportions of activated CD4+ and CD8+ T cells of the deficiency group were higher than those of the recovery group and the control group. The proportions of senescent CD4+ and CD8+ T cells in the deficiency group were comparable to those of the recovery group, which were higher than those of the control group, showing significant differences only in senescent CD8+ T cells, and no significant difference in senescent CD4+ T cells. The deficiency group expressed higher levels of effector memory CD4+ T and CD8+ T cells than the control group did, and the recovery group only expressed a higher level of effect memory CD8+ T cells. Both the deficiency group and the recovery group showed lower levels of central memory CD4+ T and CD8+ T cells than the control group did, and the recovery group had an even lower level of central memory CD4+ T cells than the deficiency group did. The recovery group showed a higher expression level of naïve CD4+ T cells, and the deficiency group and the recovery group had lower expression levels of naïve CD8+ T cells than the control group did. There was no correlation between the size of the viral reservoir of HIV-1 DNA and CD4+ T cell count or the T cell subsets. Activated CD4+ T cells, activated CD8+ T cells, and central memory CD4+ T cells were negatively correlated with the follow-up findings for CD4+ T cells, with r at －0.378, －0.334, and －0.322, respectively ( P<0.05). Naïve CD4+ T cells and naïve CD8+ T cells were positively correlated with the follow-up findings for CD4+ T cell subset, with r at 0.350 and 0.267, respectively ( P<0.05). Conclusion: HIV-1 infected persons have varying degrees of abnormal immune activation of T cell subsets. The abnormal activation of some T-cell subsets is partly associated with the subsequent recovery of immune functions and the size of the viral reservoir of HIV-1 DNA was not associated with the T cell subsets.

Histone H4 induces heparan sulfate degradation by activating heparanase in chlorine gas-induced acute respiratory distress syndrome.

BACKGROUND: Heparan sulfate (HS) degradation mediates pulmonary endothelial hyper-permeability and acute pulmonary edema during acute respiratory distress syndrome (ARDS). The aim of this study was to examine whether histone H4 induced HS degradation by activating heparanase (HPSE) in chlorine gas (Cl2)-induced ARDS. METHODS: Acute lung injury was induced by Cl2 exposure or histone H4 injection in C57BL/6 mice. Histone H4 in bronchoalveolar lavage fluid (BALF) and plasma was measured by ELISA. HS degradation was measured by immunostaining, ELISA, and flow cytometry. HPSE mRNA and protein were measured by real-time qPCR and western blot analysis, respectively, at preset timepoints. The HPSE inhibitor OGT2115 and specific siRNAs were used to study the role of HPSE during HS degradation caused by Cl2 exposure or histone H4 challenge. Blocking antibodies against TLR1, TLR2, TLR4, or TLR6 were used in vitro to investigate which signaling pathway was involved. The transcriptional regulation of HPSE was studied vis-à-vis NF-κB, which was assessed by nuclear translocation of NF-κB p65 and phosphorylation of I-κBα protein. RESULTS: Histone H4 in BALF and plasma increased evidently after Cl2 inhalation. Cl2 exposure or histone H4 challenge caused obvious acute lung injury in mice, and the pulmonary glycocalyx was degraded evidently as observed from endothelial HS staining and measurement of plasma HS fragments. Pretreatment with OGT2115, an HPSE inhibitor, relieved the acute lung injury and HS degradation caused by Cl2 exposure or histone H4 challenge. Targeted knockdown of HPSE by RNA interference (RNAi) significantly inhibited histone H4 induced HS degradation in HPMECs, as measured by immunofluorescence and flow cytometry. By inducing phosphorylation of I-κB α and nuclear translocation of NF-κB p65, histone H4 directly promoted mRNA transcription and protein expression of HPSE in a dose-dependent manner. Additionally, a blocking antibody against TLR4 markedly inhibited both activation of NF-κB and expression of HPSE induced by histone H4. CONCLUSIONS: Histone H4 is a major pro-inflammatory mediator in Cl2-induced ARDS in mice, and induces HS degradation by activating HPSE via TLRs- and NF-κB-signaling pathways.

Distribution of risk factors of ischemic stroke in Chinese young adults and its correlation with prognosis.

BACKGROUND: The risk factors for ischemic stroke in young people are complex, varied and closely related to prognosis. This study aims to analyze the risk factors for ischemic stroke in Chinese young people and to explore the main factors influencing the prognosis. METHOD: A total of 444 patients aged 16 to 45 years with ischemic stroke admitted to Suzhou tertiary hospital from 2011 to 2019 were retrospectively analyzed. Risk factors were identified according to the IPSS definition of pediatric stroke and the TOAST classification. All patients were followed up, and the modified Rankin score was used to evaluate the prognosis. Logistic regression analysis was used to explore the influencing factors of poor prognosis. RESULTS: Among the patients, 12 risk factors were found according to the IPSS definition of pediatric stroke, and 5 types of stroke were found according to the TOAST classification. A total of 299 patients had a good prognosis. Anemia, venous sinus thrombosis, isolated large-vessel occlusion, and high baseline NIHSS score were significant risk factors. CONCLUSION: The IPSS definition enables patients to be classified on the basis of more risk factors than other classification methods. The prognosis of ischemic stroke in young people is generally good in the 5 years following the event. Anemia, venous sinus thrombosis, isolated large-vessel occlusion and high baseline NIHSS score were associated with poor prognosis.

Anthropogenic Emission Sources of Sulfate Aerosols in Hangzhou, East China: Insights from Isotope Techniques with Consideration of Fractionation Effects between Gas-to-Particle Transformations.

Sulfate (SO42-) is a major species in atmospheric fine particles (PM2.5), inducing haze formation and influencing Earth's climate. In this study, the δ34S values in PM2.5 sulfate (δ34S-SO42-) were measured in Hangzhou, east China, from 2015 September to 2016 October. The result showed that the δ34S-SO42- values varied from 1.6 to 6.4‰ with the higher values in the winter. The estimated fractionation factor (α34Sg→p) from SO2 to SO42- averaged at 3.9 ± 1.6‰. The higher α34Sg→p values in the winter were mainly attributed to the decrease of ambient temperature. We further compared the quantified source apportionments of sulfate by isotope techniques with and without the consideration of fractionation factors. The result revealed that the partitioned emission sources to sulfate with the consideration of the fractionation effects were more logical, highlighting that fractionation effects should be considered in partitioning emission sources to sulfate using sulfur isotope techniques. With considering the fractionation effects, coal burning was the dominant source to sulfate (85.5%), followed by traffic emissions (12.8%) and oil combustion (1.7%). However, the coal combustion for residential heating contributed only 0.9% to sulfate on an annual basis in this megacity.

Important Role of NO3 Radical to Nitrate Formation Aloft in Urban Beijing: Insights from Triple Oxygen Isotopes Measured at the Tower.

Until now, there has been a lack of knowledge regarding the vertical profiles of nitrate formation in the urban boundary layer (BL) based on triple oxygen isotopes. Here, we conducted vertical measurements of the oxygen anomaly of nitrate (Δ17O-NO3-) on a 325 m meteorological tower in urban Beijing during the winter and summer. The simultaneous vertical measurements suggested different formation mechanisms of nitrate aerosols at ground level and 120 and 260 m in the winter due to the less efficient vertical mixing under stable atmospheric conditions. Particularly, different chemical processes of nitrate aerosols at the three heights were found between clean days and polluted days in the winter. On clean days, nocturnal chemistry (NO3 + HC and N2O5 uptake) contributed to nitrate production equally with OH/H2O + NO2 at ground level, while it dominated aloft (contributing 80% of nitrate production at 260 m), due to the higher aerosol liquid water content and O3 concentration there. On polluted days, nocturnal reactions dominated the formation of nitrate at the three heights. Particularly, the contribution of the OH/H2O + NO2 pathway to nitrate production increased from the ground level to 120 m might be attributed to the hydrolysis of NO2 to HONO and then further photolysis to OH radicals in the day. In contrast, the proportion of N2O5 + H2O decreased at 260 m, likely due to the low relative humidity aloft that inhibited the N2O5 hydrolysis reactions in the residual layer. Our results highlighted that the differences between meteorology and gaseous precursors could largely affect particulate nitrate formation at different heights within the polluted urban BL.

Optimal encephalitis/meningitis roadmap via precise diagnosis and treatment (IMPROVE): a study protocol for a randomized controlled trial.

BACKGROUND: Encephalitis/meningitis brings a heavy disease burden, and the origin of disease remains unknown in 30-40% of patients. It is greatly significant that combinations of nucleic acid amplification and autoimmune antibody testing improves the diagnosis and treatment of encephalitis/meningitis. Moreover, though several diagnostic methods are in clinical use, a recognized and unified diagnosis and treatment process for encephalitis management remains unclear. METHODS: IMPROVE is a multicenter, open label, randomized controlled clinical trial that aims to evaluate the diagnostic performance, applications, and impact on patient outcomes of a new diagnostic algorithm that combines metagenomic next-generation sequencing (mNGS), multiplex polymerase chain reaction (PCR) and autoimmune antibody testing. The enrolled patients will be grouped into two parallel groups, multiplex PCR test plus autoimmune antibody group (Group I) or the mNGS plus autoimmune antibody group (Group II) with a patient ratio of 1:1. Both groups will be followed up for 12 months. The primary outcomes include the initial time of targeted treatment and the modified Rankin scale score on the 30th day of the trial. The secondary outcomes are the cerebrospinal fluid index remission rate on the 14th day, mortality rate on the 30th day, and an evaluation of diagnostic efficacy. The two groups are predicted to comprise of 484 people in total. DISCUSSION: To optimize the roadmap of encephalitis/meningitis, precise diagnosis, and treatment are of great significance. The effect of rapid diagnosis undoubtedly depends on the progression of new diagnostic tests, such as the new multiplex PCR, mNGS, and examination of broad-spectrum autoimmune encephalitis antibodies. This randomized-controlled study could allow us to obtain an accurate atlas of the precise diagnostic ability of these tests and their effect on the treatment and prognosis of patients. Trial registration ClinicalTrial.gov, NCT04946682. Registered 29 June 2021, 'Retrospectively registered', https://clinicaltrials.gov/ct2/show/NCT04946682?term=NCT04946682&draw=2&rank=1.