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1.
World J Surg Oncol ; 19(1): 295, 2021 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-34615531

RESUMO

BACKGROUND: Laennec's capsule has been found for about 200 years. However, laparoscopic anatomical right and left hemihepatectomy (LARH and LALH) using Laennec's approach are rarely reported. METHODS: We retrospectively analyzed the technical details and the surgical outcomes of 15 patients who underwent LAH via Laennec's approach between May 2017 and July 2020. The operation time, intraoperative blood loss, postoperative complications, and hospital stay were recorded and analyzed. RESULTS: Four of 15 patients were diagnosed with hepatic hemangioma, 2 had hepatolithiasis, and 9 patients had primary liver cancer. During the surgery, Laennec's approach was used for LAH without conversion to open surgery. Four patients were treated with LARH, and 11 patients were cured with LALH. The mean age of the patients was 62.1 ± 6.5 years, and four were male. The mean operative time, blood loss, and length of the postoperative hospital stay were 193 ± 49 min, 247 ± 120 mL, and 8.7 ± 2.0 days, respectively. There was no incidence of postoperative bile leakage and bleeding. No mortality occurred. We also demonstrated that Laennec's capsule does exist around the peripheral hepatic veins with histological confirmation. CONCLUSIONS: Laennec's approach is safe and feasible for LAH. Precise isolation of Laennec's approach based on Laennec's capsule helps to standardize the surgical techniques for laparoscopic anatomical hepatectomy.


Assuntos
Laparoscopia , Litíase , Hepatopatias , Idoso , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Retrospectivos
2.
Perfusion ; : 2676591211049314, 2021 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-34617860

RESUMO

PURPOSE: In this article, we aimed to elaborate on perioperative and complication management in treatment of pheochromocytoma crisis with extracorporeal membrane oxygenation (ECMO). MATERIAL AND METHODS: We report a case of relatively rare grant paraganglioma-induced pheochromocytoma crisis leading to severe circulatory failure, treated with venoarterial extracorporeal membrane oxygenation (V-A ECMO) as a bridge to curative adrenalectomy. Weaning of ECMO was followed by successful surgical removal of the tumor, and patient survival. However, distal ischemia of the cannulated leg occurred during ECMO operation, which eventually led to amputation. In addition, the patient developed new cerebral infarction and left hemiplegia, half a month after paraganglioma resection. CONCLUSIONS: We believe that patients with pheochromocytoma crisis, who cannot maintain blood circulation, are eligible for V-A ECMO treatment. Moreover, care should be taken to prevent thrombosis and individualized and precise blood pressure management targets. Early detection and treatment of thrombosis is imperative to long-term prognosis of patients with ECMO.

3.
Pharmacol Res ; : 105917, 2021 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-34597809

RESUMO

Closely associated with type 2 diabetes mellitus (T2DM), hepatic steatosis and cardiac hypertrophy resulting from chronic excess intake can exacerbate insulin resistance (IR). The current study aims to investigate the pharmacological effects of hirsutine, one indole alkaloid isolated from Uncaria rhynchophylla, on improving hepatic and cardiac IR, and elucidate the underlying mechanism. T2DM and IR in vivo were established by high-fat diet (HFD) feeding for 3 months in C57BL/6J mice. In vitro IR models were induced by high-glucose and high-insulin (HGHI) incubation in HepG2 and H9c2 cells. Hirsutine administration for 8 weeks improved HFD-induced peripheral hyperglycemia, glucose tolerance and IR by OGTT and ITT assays, and simultaneously attenuated hepatic steatosis and cardiac hypertrophy by pathological observation. The impaired p-Akt expression was activated by hirsutine in liver and heart tissues of HFD mice, and also in the models in vitro. Hirsutine exhibited the effects on enhancing glucose consumption and uptake in IR cell models via activating phosphatidylinositol 3-kinase (PI3K)/Akt pathway, which was blocked by PI3K inhibitor LY294002. Moreover, the effect of hirsutine on promoting glucose uptake and GLUT4 expression in HGHI H9c2 cells was also prevented by Compound C, an inhibitor of AMP-activated protein kinase (AMPK). Enhancement of glycolysis might be another factor of hirsutine showing its effects on glycemic control. Collectively, it was uncovered that hirsutine might exert beneficial effects on regulating glucose homeostasis, thus improving hepatic and cardiac IR, and could be a promising compound for treating diet-induced T2DM.

4.
Exp Eye Res ; : 108796, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34662543

RESUMO

The growing need for viewing the detailed 3D structures of various tissues and organs requires advanced tissue processing and imaging techniques. However, light scattering by tissues hinders detailed structural observations. To overcome this, the emerging technique of "tissue optical clearing" has been flourishing in recent decades and provides great opportunities for imaging deep, micro-scale structures of various organs, or even of the whole body. In recent years, advanced tissue clearing techniques have been optimized for specific tissues and organs. Among these tissues, the eye is unique owing to its delicate structure and pigmented retinal epithelial cells, calling for more work on making these tissues "transparent". In this review, we searched Medline and Embase for studies published between January 2006 and August 2021 using the terms "tissue optical clearing", "ophthalmology", "eye", and "optical clearing agents", and we reviewed the publications on the optical clearing techniques of eye tissue from 2006 to the present, including both the clearing procedures and the subsequent analytical processes, thus gaining more insight into the application of tissue optical clearing in basic eye research. Furthermore, we discuss the future potential of optical clearing applications in clinical ophthalmology.

5.
Postgrad Med J ; 2021 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-34663633

RESUMO

PURPOSE: This is a nationwide-based retrospective study aiming to compare the three different scoring systems (CHA2DS2-VASc, C2HEST and HAVOC scores) in the prediction of atrial fibrillation (AF) in patients with rheumatological disease. METHODS: We used the Fine and Gray model to estimate the risk of AF (subhazard ratio and 95% CI). The predictive accuracy and discriminatory ability of the predictive model were evaluated by receiver operating characteristic (ROC) curve. RESULTS: Among the three predictive models, the model using CHA2DS2-VASc score had the better discriminative ability with an ROC of 0.79. The model with C2HEST score had an ROC of 0.78. The discriminative ability of the HAVOC score was 0.77, estimated by ROC. CONCLUSION: We concluded the CHA2DS2-VASc score has better performance in predicting AF compared with C2HEST score or HAVOC score.

6.
Front Microbiol ; 12: 737458, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34650538

RESUMO

Billions of people suffer from dental caries every year in spite of the effort to reduce the prevalence over the past few decades. Streptococcus mutans is the leading member of a specific group of cariogenic bacteria that cause dental caries. S. mutans forms biofilm, which is highly resistant to harsh environment, host immunity, and antimicrobial treatments. In this study, we found that S. mutans biofilm is highly resistant to both antimicrobial agents and lysozyme. DexA70, the truncated form of DexA (amino acids 100-732), a dextranase in S. mutans, prevents S. mutans biofilm formation and disassembles existing biofilms within minutes at nanomolar concentrations when supplied exogenously. DexA70 treatment markedly enhances biofilm sensitivity to antimicrobial agents and lysozyme, indicating its great potential in combating biofilm-related dental caries.

7.
J Clin Psychol ; 2021 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-34655439

RESUMO

OBJECTIVES: Both nonsuicidal self-injury (NSSI) and Internet addiction (IA) are important health issues for adolescents, and social support has been extensively examined as a protective factor for both. This study aims to compare the effect of offline and online social support on IA, and that on NSSI as well. METHOD: A total of 1911 Chinese adolescents (53.27% females, Mage = 16.83 ± 0.37) completed self-report questionnaires assessing offline social support, online social support, IA, and NSSI. RESULTS: The structural equation modeling analysis showed that offline social support was negatively associated with IA and NSSI, while online social support was positively associated with IA and NSSI; IA was positively associated with NSSI. Furthermore, implications for preventions and interventions of IA and NSSI were discussed. The indirect model explained a relatively small variance of NSSI, indicating the possibility of additional factors in the development of NSSI that should be further investigated. CONCLUSION: This study indicated the differences between offline and online social support, and their different associations with IA and NSSI.

8.
Parasit Vectors ; 14(1): 532, 2021 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-34649608

RESUMO

Immunofluorescence assay is one of methods to understand the spatial biology by visualizing localization of biomolecules in cells and tissues. Autofluorescence, as a common phenomenon in organisms, is a background signal interfering the immunolocalization assay of schistosome biomolecules, and may lead to misinterpretation of the biomolecular function. However, applicable method for reducing the autofluorescence in Schistosoma remains unclear. In order to find a suitable method for reducing autofluorescence of schistosomes, different chemical reagents, such as Sudan black B (SBB), trypan blue (TB), copper sulfate (CuSO4), Tris-glycine (Gly), and ammonia/ethanol (AE), at different concentrations and treatment time were tested, and SBB and CuSO4 were verified for the effect of blocking autofluorescence in immunofluorescence to localize the target with anti-SjCRT antibody. By comparing the autofluorescence characteristics of different conditions, it was found that SBB, TB and CuSO4 had a certain degree of reducing autofluorescence effect, and the best effect in females was using 50 mM CuSO4 for 6 h and in males was 0.5% SBB for 6 h. Furthermore, we have applied the optimized conditions to the immunofluorescence of SjCRT protein, and the results revealed that the immunofluorescence signal of SjCRT was clearly visible without autofluorescence interference. We present an effective method to reduce autofluorescence in male and female worm of Schistosoma japonicum for immunofluorescence assay, which could be helpful to better understand biomolecular functions. Our method provides an idea for immunofluorescence assay in other flukes with autofluoresence.

9.
Adipocyte ; 10(1): 463-474, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34641739

RESUMO

The aim of the present study is to explored the relationship between ADIPO signalling pathway and T2DM, to provide clues for further study of the pathogenesis of T2DM and to determine the possible drug targets. This study employed a case-control study design. Twenty-three single nucleotide polymorphisms (SNPs) of 13 genes in the selected ADIPO signalling pathway were genotyped by SNPscanTM kit. All statistical analysis was performed by SPSS 25.0, PLINK 1.07, R 2.14.2, Haploview 4.2, SNPstats, and other statistical software packages. In the association analysis based on a single SNPs, rs1044471 had statistical significance in the overdominant model without adjusting covariates. Rs1042531 had statistical significance in the overdominant model. Rs12718444 had statistical significance in the recessive model. There was a linkage disequilibrium between the loci within 9 genes, and the two loci in RXRA gene did not form blocks. Four kernel functions were used for SNPs set analysis based on ADIPO signalling pathway showed that there was no statistical significance whether covariates were added or not, P>0.05.According to our research results, it is found that some single nucleotide polymorphisms (ADIPOR2 rs1044471, PCK1 rs1042531, GLUT1 rs12718444) in the adiponectin signalling pathway may be associated with T2DM.

10.
Plant Physiol Biochem ; 167: 1049-1060, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34600182

RESUMO

Previously, we obtained a wax-deficient mutant 'Ganqi 3' (MT) from 'Newhall' navel orange (Citrus sinensis [L.] Osbeck cv. Newhall, WT). The weight loss and postharvest decay in MT fruit were much higher than those in WT fruit after long-term cold storage. To understand the underlying mechanism, the changes in the morphology, chemical composition and gene expression of cuticular waxes between WT and MT fruit were compared during 150 days of storage at 4 °C. The density of epicuticular wax crystals and the contents of most of the aliphatic wax fractions in MT fruit were much lower than those in WT fruit over 90 days of storage. Further research revealed that the differences in the morphology and chemical composition of cuticular waxes might be important causes for the differences of postharvest weight loss and decay rates between WT and MT fruit. Notably, the expression profiles of 16 wax-related genes in WT and MT fruit were consistent with the change trends of corresponding cuticular wax components during cold storage. These results suggest that the morphology and chemical composition of cuticular waxes may be regulated by wax-related genes and play an important role in regulating the postharvest weight loss and the tolerances to postharvest decay in navel orange.


Assuntos
Citrus sinensis , Citrus sinensis/genética , Frutas , Expressão Gênica , Ceras
12.
Adv Mater ; : e2107103, 2021 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-34636109

RESUMO

Most previous efforts are devoted to developing transition metals as electrocatalysts guided by the d-band center model. The metals of the s-block of the periodic table have so far received little attention in the application of oxygen reduction reactions (ORR). Herein, a carbon catalyst with calcium (Ca) single atom coordinated with N and O is reported, which displays exceptional ORR activities in both acidic condition (E1/2  = 0.77 V, 0.1 m HClO4 ) and alkaline condition (E1/2  = 0.90 V, 0.1 m KOH). The CaN, O/C exhibits remarkable performance in zinc-air battery with a maximum power density of 218 mW cm-2 , superior to a series of catalysts reported so far. X-ray absorption near-edge structure (XANES) characterization confirms the formation of N- and O-atom-coordinated Ca in the carbon matrix. Density functional theory (DFT) calculations reveal that the high catalytic activity of main-group Ca is ascribed to the fact that its p-orbital electron structure is regulated by N and O coordination so that the highest peak (EP ) of the projected density of states (PDOS) for the Ca atom is moved close to the Fermi level, thereby facilitating the adsorption of ORR intermediates and electron transfer.

13.
Artigo em Inglês | MEDLINE | ID: mdl-34612043

RESUMO

As the frontier in heterogeneous catalyst, a monomer and positively charged active sites in the single-atom catalyst (SAC), anchored by high electronegative N, O, S, P, etc., atoms, may not be active for the multispecies (O2, substrates, intermediates, solvent etc.) involved liquid-phase aerobic oxidation. Here, with catalytic, aerobic oxidation of 5-hydroxymethylfurfural as an example, Pt SAC (Pt1-N4) was synthesized and tested first. With commercial Pt/C (Pt loading of 5 wt %) as a benchmark, 2,5-furandicarboxylic acid (FDCA) yield of 97.6% was obtained. Pt SAC (0.56 wt %) gave a much lower FDCA yield (28.8%). By changing the coordination atoms from highly electronegative N to low electronegative Co atoms, the prepared Pt single-atom alloy (SAA, Pt1-Co3) catalyst with ultralow Pt loading (0.06 wt %) gave a much high FDCA yield (99.6%). Density functional theory (DFT) calculations indicated that positively charged Pt sites (+0.712e) in Pt1-N4 almost lost the capability for oxygen adsorption and activation, as well as the adsorption for the key intermediate. In Pt1-Co3 SAA, the central negatively charged Pt atom (-0.446e) facilitated the adsorption of the key intermediate; meanwhile, the nearby Co atoms around the Pt atom constituted the O2-preferred adsorption/activation sites. This work shows the difference between the SAC with NPs and the SAA during liquid-phase oxidation of HMF and gives a useful guide in the future single-atom catalyst design in other related reactions.

14.
Cancer Cell Int ; 21(1): 545, 2021 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-34663322

RESUMO

BACKGROUND: Papillary renal cell carcinoma (pRCC) ranks second in renal cell carcinoma and the prognosis of pRCC remains poor. Here, we aimed to screen and identify a novel prognostic cancer-related lncRNA signature in pRCC. METHODS: The RNA-seq profile and clinical feature of pRCC cases were downloaded from TCGA database. Significant cancer-related lncRNAs were obtained from the Immlnc database. Differentially expressed cancer-related lncRNAs (DECRLs) in pRCC were screened for further analysis. Cox regression report was implemented to identify prognostic cancer-related lncRNAs and establish a prognostic risk model, and ROC curve analysis was used to evaluate its precision. The correlation between RP11-63A11.1 and clinical characteristics was further analyzed. Finally, the expression level and role of RP11-63A11.1 were studied in vitro. RESULTS: A total of 367 DECRLs were finally screened and 26 prognostic cancer-related lncRNAs were identified. Among them, ten lncRNAs (RP11-573D15.8, LINC01317, RNF144A-AS1, TFAP2A-AS1, LINC00702, GAS6-AS1, RP11-400K9.4, LUCAT1, RP11-63A11.1, and RP11-156L14.1) were independently associated with prognosis of pRCC. These ten lncRNAs were incorporated into a prognostic risk model. In accordance with the median value of the riskscore, pRCC cases were separated into high and low risk groups. Survival analysis indicated that there was a significant difference on overall survival (OS) rate between the two groups. The area under curve (AUC) in different years indicated that the model was of high efficiency in prognosis prediction. RP11-63A11.1 was mainly expressed in renal tissues and it correlated with the tumor stage, T, M, N classifications, OS, PFS, and DSS of pRCC patients. Consistent with the expression in pRCC tissue samples, RP11-63A11.1 was also down-regulated in pRCC cells. More importantly, up-regulation of RP11-63A11.1 attenuated cell survival and induced apoptosis. CONCLUSIONS: Ten cancer-related lncRNAs were incorporated into a powerful model for prognosis evaluation. RP11-63A11.1 functioned as a cancer suppressor in pRCC and it might be a potential therapeutic target for treating pRCC.

15.
Mol Cancer Res ; 2021 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-34610961

RESUMO

Aberrant epigenetic transcriptional regulation is linked to metastasis, a primary cause of cancer-related death. Dissecting the epigenetic mechanisms controlling metastatic progression may uncover important insights to tumor biology and potential therapeutic targets. Here, we investigated the role of the SIN3A histone deacetylase 1 and 2 (SIN3A-HDAC1/2) complex in cancer metastasis. Using a mouse model of melanoma metastasis, we found that the SIN3A-HDAC1/2 transcription repressor complex silences BMP6 expression, causing increased metastatic dissemination and tumor growth via suppression of BMP6-activated SMAD5 signaling. We further discovered that FAM83G/PAWS1, a downstream effector of BMP6-SMAD5 signaling, contributes critically to metastatic progression by promoting actin-dependent cytoskeletal dynamics and cell migration. Pharmacologic inhibition of the SIN3A-HDAC1/2 complex reduced the numbers of melanoma cells in the circulation and inhibited metastatic tumor growth by inducing disseminated cell dormancy, highlighting the SIN3A-HDAC1/2 repressor complex as a potential therapeutic target for blocking cancer metastasis. Implications: This study identifies the novel molecular links in the metastatic progression to target cytoskeletal dynamics in melanoma and identifies the SIN3A-HDAC1/2 complex and FAM83G/PAWS1 as potential targets for melanoma adjuvant therapy.

16.
Pulm Circ ; 11(4): 0271678X20978861, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34603688

RESUMO

Cartilage oligomeric matrix protein (COMP) was a protective factor in the cardiovascular system. Previous studies showed that hypoxia led to decreased COMP in rat models of pulmonary hypertension. However, the expression pattern of COMP in the pulmonary hypertension population was unclear. A total of 35 patients newly diagnosed with pulmonary hypertension and 70 controls were enrolled in the study. Circulating COMP concentrations of serum samples were measured by enzyme-linked immunosorbent assay and were analyzed the association with multiple clinical variables. Serum COMP concentrations in the pulmonary hypertension group were significantly declined in comparison with age- and sex-matched normal controls, especially in the female subgroup. No significant difference of COMP concentrations was observed in the etiological classification, heart function classification, and risk stratification. Major hemodynamic parameters, six-minute walk distance, N-terminal pro brain natriuretic peptide, and short-term prognosis were not statistically associated with COMP. However, some echocardiography parameters, like tricuspid annular plane systolic excursion and mean right atrial pressure, were found the negative relation to COMP concentrations. In conclusion, serum COMP levels were decreased in the patients with pulmonary hypertension, which was in accordance with its known biological effects. Its association with long-term prognosis was worth further exploring.

17.
Carcinogenesis ; 2021 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-34606590

RESUMO

Benzene is a recognized hematotoxin and leukemogen; however, its mechanism of action in humans remain unclear. To provide insight into the processes underlying benzene hematotoxicity, we performed high-resolution metabolomic (HRM) profiling of plasma collected from a cross-sectional study of 33 healthy workers exposed to benzene (median 8-hr time-weighted average exposure; 20 ppma), and 25 unexposed controls in Shanghai, China. Metabolic features associated with benzene were identified using a metabolome-wide association study (MWAS) that tested for the relationship between feature intensity and benzene exposure. MWAS identified 478 mass spectral features associated with benzene exposure at FDR<20%. Comparison to a list of 13 known benzene metabolites and metabolites predicted using a multi-component biotransformation algorithm showed five metabolites were detected, which included the known metabolites phenol and benzene diolepoxide. Metabolic pathway enrichment identified 41 pathways associated with benzene exposure, with altered pathways including carnitine shuttle, fatty acid metabolism, sulfur amino acid metabolism, glycolysis, gluconeogenesis, and branched chain amino acid metabolism. These results suggest disruption to fatty acid uptake, energy metabolism and increased oxidative stress, and point towards pathways related to mitochondrial dysfunction, which has previously been linked to benzene exposure in animal models and human studies. Taken together, these results suggest benzene exposure is associated with disruption of mitochondrial pathways, and provide promising, systems biology biomarkers for risk assessment of benzene-induced hematotoxicity in humans.

18.
Sci Total Environ ; : 150997, 2021 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-34656588

RESUMO

This study reports the transformation behavior of nitrogen during the co-hydrothermal carbonization of sewage sludge and model compounds (microcrystalline cellulose, starch, lignin, and xylan) of food waste at 220 °C, with a focus on the reaction routes between starch/xylan and NH4+. Most of the nitrogen in the raw sludge was transformed into organic-N (44.6%) and NH4+ (23.3%) in the aqueous product, and only 20.3% of nitrogen was retained in the hydrochar. The added model compounds could react with organic-N (i.e., amino acids and amines) and NH4+ in aqueous products through Maillard and Mannich reactions, generating heterocyclic-N (especially pyrrole-N) which further polymerizes to form nitrogen-containing polyaromatic hydrochar. This leads to an increase in the retention rate of nitrogen to 36.8-50.9%, especially upon the addition of starch and xylan. During the hydrothermal carbonization of starch/xylan in the NH4+ solution, the polymers are first hydrolyzed into monomers, followed by their further reaction with NH4+ to generate pyrrole-N and pyridine-N in aqueous products (especially xylan), and the pyrrole-N can then polymerize with aromatic clusters to form hydrochar-N. The results show that the model compounds of food waste substantially affect the nitrogen transformation pathways during hydrothermal carbonization, mainly because of the structures of their monomers. These findings can guide the production of sludge-based hydrochar with the targeted regulation of nitrogen content and species.

19.
J Vet Sci ; 22(5): e72, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34553517

RESUMO

It has been speculated that bats serve as reservoirs of a huge variety of emerging coronaviruses (CoVs) that have been responsible for severe havoc in human health systems as well as negatively affecting human economic and social systems. A prime example is the currently active severe acute respiratory syndrome (SARS)-CoV2, which presumably originated from bats, demonstrating that the risk of a new outbreak of bat coronavirus is always latent. Therefore, an in-depth investigation to better comprehend bat CoVs has become an important issue within the international community, a group that aims to attenuate the consequences of future outbreaks. In this review, we present a concise introduction to CoVs found in bats and discuss their distribution in Southeast Asia. We also discuss the unique adaptation features in bats that confer the ability to be a potential coronavirus reservoir. In addition, we review the bat coronavirus-linked diseases that have emerged in the last two decades. Finally, we propose key factors helpful in the prediction of a novel coronavirus outbreak and present the most recent methods used to forecast an evolving outbreak.


Assuntos
Quirópteros/virologia , Coronavirus/classificação , SARS-CoV-2 , Animais , Ásia Sudeste , Saúde Global
20.
Environ Pollut ; 291: 118114, 2021 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-34536649

RESUMO

Low molecular weight organic compounds are ubiquitous in the atmosphere. However, knowledge on their concentrations and molecular distribution in fresh snow remains limited. Here, twelve fresh snow samples collected at eight sites in China were investigated for dicarboxylic acids and related compounds (DCRCs) including oxocarboxylic acids and α-dicarbonyls. Dissolved organic carbon (DOC) concentrations in the snow samples ranged from 0.99 to 14.6 mg C L-1. Concentrations of total dicarboxylic acids were from 225 to 1970 µg L-1 (av. 650 µg L-1), while oxoacids (28.3-173, av. 68.1 µg L-1) and dicarbonyls (12.6-69.2, av. 31.3 µg L-1) were less abundant, accounting for 4.6-8.5% (6.2%), 0.45-1.4% (0.73%), and 0.12-0.88% (0.46%) of DOC, respectively. Molecular patterns of dicarboxylic acids are characterized by a predominance of oxalic acid (C2) (95.0-1030, av. 310 µg L-1), followed by phthalic (Ph) (9.69-244, av. 69.9 µg L-1) or succinic (C4) (23.8-163, av. 63.7 µg L-1) acid. Higher concentrations of Ph in snow from Beijing and Tianjin than other urban and rural regions suggest significant emissions from vehicular exhausts and other fossil fuel combustion sources in megacities. C2 constituted 40-54% of total diacids, corresponding to 1.5-2.6% of snow DOC. The total measured DCRCs represent 5.5-10% of snow DOC, which suggests that there are large amounts of unknown organics requiring further investigations. The spatial distributions of diacids exhibited higher loadings in megacities than rural and island sites. Molecular distributions of diacids indicated that the photochemical modification was restrained under the weak solar radiation during the snow events, while anthropogenic primary sources had a more significant influence in megacities than rural areas and islands.

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