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1.
Int J Biol Sci ; 16(2): 216-227, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31929750

RESUMO

Background and aims: Dysfunction of the immune regulatory system plays a role in the pathogenesis of allergic rhinitis (AR). The underlying mechanism needs to be further investigated. Published data indicate that soluble CD83 (sCD83) has immune regulatory activities. This study aims to investigate the role of sCD83 in the alleviation of experimental AR. Methods: Peripheral blood samples were obtained from AR patients. Serum levels of sCD83 were determined by enzyme-linked immunosorbent assay. A murine AR model was developed to test the effects of sCD83 on suppressing experimental AR. Results: We found that serum levels of sCD83 in the AR group were lower than that in the healthy control group. A negative correlation was identified between the serum sCD83 levels and the frequency of T helper-2 (Th2) cells. The low serum sCD83 levels were also associated with the Bcl2L12 expression in antigen-specific Th2 cells. Exposure to sCD83 enhanced the responsiveness of antigen-specific Th2 cells to apoptosis inducers via suppressing the Bcl2L12 expression. Administration of sCD83 efficiently suppressed experimental AR. Conclusions: sCD83 contributes to immune homeostasis by regulating CD4+ T cell activities. Administration of sCD83 may have translational potential for the treatment of AR or other allergic diseases.

2.
Bioorg Med Chem Lett ; 30(4): 126956, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31932222

RESUMO

Three new pentacyclic triterpenoid saponins (1-3), together with medicagenic acid (4) were isolated and purified from 70% EtOH extract of Medicago sativa L. by different column chromatographic and semi-preparative HPLC. Their structures were established by direct interpretation of their spectral data, mainly HR-ESI-MS, 1D-NMR, 2D-NMR, and chemical methods, as well as comparison with literature data. Additionally, all isolates were evaluated for their neuroprotective activities against H2O2-induced damage in human neuroblastoma SHSY5Y cells. As a results, compounds 1 and 2 (67.14% and 73.05%) exhibited potent neuroprotective activities. These findings provide new insights into developing better treatment of neurodegenerative diseases for M. sativa in the future.

3.
Molecules ; 25(3)2020 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-31991928

RESUMO

A highly efficient sulfonylation of para-quinone methides with sulfonyl hydrazines in water has been developed on the basis of the mode involving a tetrabutyl ammonium bromide (TBAB)-promoted sulfa-1,6-conjugated addition pathway. This reaction provides a green and sustainable method to synthesize various unsymmetrical diarylmethyl sulfones, showing good functional group tolerance, scalability, and regioselectivity. Further transformation of the resulting diarylmethyl sulfones provides an efficient route to some functionalized molecules.

4.
Inflammation ; 2020 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-31938979

RESUMO

The skewed T helper (Th) 2 response plays a critical role in the pathogenesis of allergic asthma. Regulatory T (Treg) cells and the regulatory cytokines are required in maintaining the homeostasis in the body. This study aims to determine the effects of a poly(lactic-co-glycolic) acid (PLGA)-ovalbumin (OVA)+A20 (a ubiquitin E3 ligase) nanovaccine on inhibiting allergic asthma in a murine model. In this study, A20 and OVA (a model antigen) were encapsulated into PLGA to be a nanovaccine (PLGA-OVA+A20). An allergic asthma murine model was developed with OVA as the specific antigen to test the role of PLGA-OVA+A20 nanovaccine in maintaining the immune homeostasis in the airway tissues. The results showed that PLGA-OVA+A20 nanovaccine inhibited the asthma responses in mice by suppressing Th2 inflammatory responses, promoting the generation of Treg cells in the airway tissues. We conclude that the PLGA-OVA+A20 nanovaccine has a marked inhibitory effect on the airway allergic response in sensitized mice by significantly promoting the generation of Treg cell and IL-10. The data suggest that PLGA-OVA+A20 has translational potential in the treatment of allergic asthma.

5.
Mater Sci Eng C Mater Biol Appl ; 108: 110512, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31924017

RESUMO

980-nm-upconverted 530 and 550 nm Er3+ green fluorescence spectra of Er3+/Yb3+-codoped NaGd(WO4)2 submicron crystals were measured in the temperature range of 298-383 K. A sextuple ratiometric thermometry is proposed. It is established on the basis of six schemes of fluorescence intensity ratio (FIR) that considers three component peaks of the 530 nm emission band and two component peaks of the 550 nm emission band, which involve electronic transitions between two Stark sublevels of Er3+. The study shows that the phosphor shows strong green fluorescence, which is verified by measured quantum yield, and thermally stable spectral structure desired for the sextuple ratiometric thermometry. All of the six FIR schemes display highly efficient sensing performances with slightly different thermal sensitivities. Each scheme gives a temperature value and the six schemes give an averaged result. In parallel, we have also carried out an ex vivo experimental study on the temperature characteristics of the green fluorescence of the phosphor. Almost same results have been obtained, verifying biological applicability of the phosphor. The ex vivo experimental results also show that the sextuple thermometry increases considerably the accuracy and reliability of temperature measurement in comparison with the conventional intensity integration method.

6.
Dig Liver Dis ; 2019 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-31818638

RESUMO

BACKGROUND: Hepatocellular carcinoma (HCC) is one of the most lethal cancers owing to the high metastasis rate. The molecular mechanism underlying HCC progression remains unclear. AIMS: We aimed to explore the function and mechanism of action of insulin-like growth factor binding protein 2 (IGFBP2) in HCC. METHODS: Expression of IGFBP2 was evaluated with western blotting and reverse transcription polymerase chain reaction (RT-PCR). Loss- and gain-function assays were conducted to evaluate the effects of IGFBP2 on HCC cell proliferation, migration, and invasion. Signaling pathways were screened with a dual-fluorescein reporting system, and levels of epithelial and mesenchymal markers were measured after altering IGFBP2 expression. Cell fractionation analysis was conducted to evaluate the nuclear translocation of p65. RESULTS: IGFBP2 expression was upregulated in HCC tissues, predicted worse prognosis, and was associated with strong metastatic potentials. IGFBP2 depletion significantly inhibited HCC cell proliferation, migration, and invasion, whereas IGFBP2 overexpression showed reverse phenotypes. The underlying mechanism involved IGFBP2-mediated nuclear localization of p65, which activated nuclear factor kappa B (NF-κB) and zinc finger E-Box binding homeobox 1 (ZEB1) transcription via binding to the gene promoter. CONCLUSION: This study for the first time identifies IGFBP2 as a novel therapeutic target in HCC that activates the NF-κB-ZEB1 signaling axis and promotes HCC tumorigenesis.

7.
Chin Med J (Engl) ; 132(23): 2842-2847, 2019 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-31856056

RESUMO

BACKGROUND: Increased right ventricle afterload during acute respiratory distress syndrome (ARDS) may induce acute cor pulmonale (ACP), which is associated with a poor clinical outcome. Echocardiography is now considered as a rapid and non-invasive tool for diagnosis of ACP. The aims of this study were to investigate the morbidity and mortality rates of ACP in ARDS patients in intensive care units (ICUs) across the mainland of China and to determine the severity and prognosis of ACP in ARDS patients through an ultrasound protocol (TRIP). And the association between ACP related factors and the ICU mortality will be revealed. METHODS: This study is a multicenter and cross-sectional study in China which will include ICU participants when diagnosed as ARDS. The ultrasound protocol, known as the TRIP, is proposed as severity assessment for ACP, which includes tricuspid regurgitation velocity (T), right ventricular size (R), inferior vena cava diameter fluctuation (I), and pulmonary regurgitation velocity (P). The 28-day mortality, ICU/hospital mortality, the length of stay in ICU, mechanical ventilation days, hemodynamic parameters and lab parameters of liver function and kidney function are all recorded. DISCUSSION: This large-scale study would give a sufficient epidemic investigation of ACP in ARDS patients in China. In addition, with the TRIP protocol, we expect that we could stratify ACP with more echocardiography parameters. TRIAL REGISTRATION: NCT03827863, https://clinicaltrials.gov/ct2/show/NCT03827863.

8.
Sci Rep ; 9(1): 19842, 2019 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-31882617

RESUMO

Adsorbed sulfur has been investigated on the Ag(110) surface at two different coverages, 0.02 and 0.25 monolayers. At the lower coverage, only sulfur adatoms are present. At the higher coverage, there are additional bright features which we identify as linear, independent AgS2 complexes. This identification is based upon density functional theory (DFT) and its comparison with experimental observations including bias dependence and separation between complexes. DFT also predicts the absence of AgS2 complexes at low coverage, and the development of AgS2 complexes around a coverage of 0.25 monolayers of sulfur, as is experimentally observed. To our knowledge, this is the first example of an isolated linear sulfur-metal-sulfur complex.

9.
Phys Chem Chem Phys ; 21(48): 26483-26491, 2019 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-31776538

RESUMO

Experimental data from low-temperature Scanning Tunneling Microscopy (LTSTM) studies on coinage metal surfaces with very low coverages of S is providing new insights into metal-S interactions. A previous LTSTM study for Cu(100), and a new analysis reported here for Ag(100), both indicate no metal-sulfur complex formation, but an Au4S5 complex was observed previously on Au(100). In marked contrast, various complexes have been proposed and/or observed on Ag(111) and Cu(111), but not on Au(111). Also, exposure to trace amounts of S appears to enhance mass transport far more dramatically on (111) than on (100) surfaces for Cu and Ag, a feature tied to the propensity for complex formation. Motivated by these observations, we present a comprehensive assessment at the level of DFT to assess the existence and stability of complexes on (100) surfaces, and compare results with previous analyses for (111) surfaces. Consistent with experiment, our DFT analysis finds no stable complexes on Ag(100) and Cu(100), but several exist for Au(100). In addition, we systematically relate stability for adsorbed and gas-phase species within the framework of Hess's law. We thereby provide key insight into the various energetic contributions to stability which in turn elucidates the difference in behavior between (100) and (111) surfaces.

10.
Chin Med J (Engl) ; 2019 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-31764188

RESUMO

BACKGROUND: Increased right ventricle afterload during acute respiratory distress syndrome (ARDS) may induce acute cor pulmonale (ACP), which is associated with a poor clinical outcome. Echocardiography is now considered as a rapid and non-invasive tool for diagnosis of ACP. The aims of this study were to investigate the morbidity and mortality rates of ACP in ARDS patients in intensive care units (ICUs) across the mainland of China and to determine the severity and prognosis of ACP in ARDS patients through an ultrasound protocol (TRIP). And the association between ACP related factors and the ICU mortality will be revealed. METHODS: This study is a multicenter and cross-sectional study in China which will include ICU participants when diagnosed as ARDS. The ultrasound protocol, known as the TRIP, is proposed as severity assessment for ACP, which includes tricuspid regurgitation velocity (T), right ventricular size (R), inferior vena cava diameter fluctuation (I), and pulmonary regurgitation velocity (P). The 28-day mortality, ICU/hospital mortality, the length of stay in ICU, mechanical ventilation days, hemodynamic parameters and lab parameters of liver function and kidney function are all recorded. DISCUSSION: This large-scale study would give a sufficient epidemic investigation of ACP in ARDS patients in China. In addition, with the TRIP protocol, we expect that we could stratify ACP with more echocardiography parameters. TRIAL REGISTRATION: NCT03827863, https://clinicaltrials.gov/ct2/show/NCT03827863.

11.
Atherosclerosis ; 291: 71-77, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31704553

RESUMO

BACKGROUND AND AIMS: Atherosclerosis is an important contributing factor to cardiovascular mortality. The role of Helicobacter pylori (H. pylori) infection in atherosclerosis is inconsistent and sometimes controversial. The present study aimed to determine if H. pylori infection is associated with carotid atherosclerosis. METHODS: 17,613 males and females with both carotid ultrasonic examination and 13C-urea breath test for H. pylori infection were screened by a major Chinese university hospital from March 2012 to March 2017 for the study. Baseline demographics, cardiac risk factors, and laboratory studies were obtained. After exclusion for pre-specified conditions, 12,836 individuals were included in the analysis, including 8157 men (63.5%) and 4679 women (36.5%). Analysis was also made for 5-year follow-up data of 1216 subjects (869 males and 347 females) with and without H. pylori infection for development and progression of carotid atherosclerosis. RESULTS: After adjusting for age, sex, body mass index, lipid profile, hypertension, renal function, diabetes mellitus, and smoking, H. pylori infection was found as an independent risk factor for carotid atherosclerosis in males under 50 years, but not in older males or females (odds ratio 1.229, 95% CI 1.054-1.434, p = 0.009). Follow-up data analysis showed that the incidence of carotid atherosclerosis from no atherosclerosis to detectable lesions was significantly higher in young males with persistent H. pylori infection than those without H. pylori infection (p = 0.028) after 3 years. CONCLUSIONS: These data suggest that H. pylori infection might be an important risk factor for carotid atherosclerosis in young Chinese males under 50.

12.
World J Pediatr ; 2019 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-31612428

RESUMO

BACKGROUND: Juvenile idiopathic arthritis (JIA) is a chronic inflammatory disease that includes seven heterogeneous subgroups with different prognoses. In particular, polyarticular JIA (pJIA) has a longer period of active disease and a poorer prognosis. Tumor necrosis factor (TNF)-alpha inhibitors are effective in patients with pJIA, but the therapeutic regimen remains controversial. Here, we performed a single-center study to determine the potential correlation between TNF-alpha inhibitor (infliximab) therapy and outcomes in these patients. METHODS: Clinical data of 40 pJIA patients were collected at our center from January 1, 2010 to January 1, 2018, and patients were grouped according to the timing of infliximab therapy. The erythrocyte sedimentation rate (ESR), the number of joints with active disease, and the 27-point juvenile arthritis disease activity score (JADAS-27) were analyzed. RESULTS: The ESR, the active joint count, and the JADAS-27 decreased significantly in all groups after 3 months (P = 0.041/0.415/0.008, 0.022/0.030/ < 0.001, and 0.05/0.012/ < 0.001, respectively) and 6 months (P = 0.036/0.045/0.041, 0.076/0.037/ < 0.001, and 0.096/0.006/ < 0.001, respectively) of infliximab treatment, although the rates of change of these parameters were similar. However, after 12 months, only patients treated with infliximab within 3 months of disease onset had a stable ESR, active joint count, and JADAS-27, while these parameters increased sharply when infliximab was administered 3 months and especially 1 year after disease onset. CONCLUSIONS: TNF-alpha is a pleiotropic pro-inflammatory cytokine of crucial importance in the pathogenesis of JIA. Infliximab can improve the outcomes of patients with pJIA significantly, and should be introduced early during the clinical course.

13.
J Epidemiol ; 2019 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-31656244

RESUMO

BACKGROUND: The objective was to evaluate the effects of personal characteristics on the validation of self-reported type 2 diabetes among Chinese adults in urban Shanghai. METHODS: During 2015 to 2016, 4,322 participants were recruited in this validation study. We considered the criteria of diabetes verification to use the laboratory assays of fasting plasma glucose (FPG), glycated hemoglobin (HbA1c), or taking diabetic medication. RESULTS: When taking diabetic medication or FPG≥7.0mmol/L was as identified diabetes, the measurements of sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and Kappa value of self-reported diabetes were 72.0%, 99.2%, 95.1%, 93.9%, and 0.78, respectively. If an additional HbA1c test was used for 708 subjects (aged<65 years), slightly lower values of sensitivity, NPV and Kappa were observed. More potential diabetes cases were found if compared to only using FPG. Subjects with the characteristics of female, older, or family history of diabetes had sensitivity over 75% and over 0.8 of excellent Kappa, while the sensitivity and Kappa of opposite groups had poorer values. Specificity, PPV and NPV were similar in different characteristics populations. The prevalence of type 2 diabetes was 19.3% in the study (14.1% diagnosed diabetes, 5.2% undiagnosed diabetes). About 26.2% of subjects were pre-diabetes. Additional HbA1c test indicated an increased prevalence of undiagnosed and pre-diabetes. CONCLUSIONS: Findings support self-reported diabetes is sufficiently valid to be used in large-scale, population-based epidemiologic studies. Participants with different characteristics may have different indicators in terms of validation such as age, gender, and family history of diabetes in first-relatives.

14.
Zhongguo Zhong Yao Za Zhi ; 44(17): 3711-3717, 2019 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-31602943

RESUMO

In this paper,the fingerprint of different varieties of chrysanthemum were established with " Similarity Evaluation System for Chromatographic Fingerprint of Chinese Materia Medica" and the content of chlorogenic acid,galuteolin and 3,5-O-dicaffeoylquinic acid in 29 batches of different varieties of chrysanthemum in Futianhe town,Huangtugang town and Wuhan city were compared. At the same time,similarity evaluation and common peak clustering analysis were carried out. There were 11 common peaks in the fingerprints of 29 batches of different varieties of chrysanthemum,and the similarity ranged from 0. 802 to 0. 975. Hangju and Gongju were divided into one group by cluster analysis,and Huangju into another category. The established fingerprint method provides a basis for the identification of chrysanthemum cultivars. The content of 29 batches of chlorogenic acid was between 4. 092 and 11. 723 mg·g-1,luteolin was between 1. 010 and 11. 713 mg·g-1,and 3,5-O-dicaffeoylquinic acid was between 8. 828 and 33. 435 mg·g-1,both reach the pharmacopoeia standard,but the effective components of different varieties of chrysanthemum were quite different. Based on the contents of three active ingredients and the diversity of fingerprint peaks,the quality of the characteristic germplasm resource of local Fubaijuin Macheng is superior,and the protection of local characteristic germplasm resource should be strengthened in production.


Assuntos
Chrysanthemum/química , Compostos Fitoquímicos/análise , Ácido Clorogênico/análogos & derivados , Ácido Clorogênico/análise , Cromatografia Líquida de Alta Pressão , Luteolina/análise
15.
Ying Yong Sheng Tai Xue Bao ; 30(10): 3356-3366, 2019 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-31621221

RESUMO

To reveal the seedlings dynamics of dominant trees and their response to canopy changes (as indicated by changes in leaf area index), we analyzed the seedlings dynamics of dominant trees and canopy structure during forest regeneration based on three-year (2014 to 2016) censuses and hemispherical photography in a 4 hm2 forest dynamics monitoring plot. The results showed that canopy LAI first decreased and then increased during the survey period, with significant interannual difference. The seedlings of 12 dominant tree species showed notable response to the change of canopy structure, with the response varying among different tree species. The relative abundance or frequency of seedlings for neutral tree species generally increased with the decreases of canopy LAI. The relative abundance or frequency of seedlings of light-demanding tree species generally decreased with the increases of canopy LAI. In multi-response permutation procedures by analyzing the numeric composition and distribution of dominant tree seedlings, there was significant difference among the three censuses. Such interannual difference gradually decreased from 2014 to 2016. Significant change occurred in the indicator species of dominant tree seedlings, reflecting their responses to the changes of canopy structure.


Assuntos
Plântula , Árvores , China , Florestas , Folhas de Planta
16.
Int Forum Allergy Rhinol ; 9(11): 1289-1296, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31623025

RESUMO

BACKGROUND: The therapeutic efficacy of allergic rhinitis (AR) needs to be improved. Probiotics have immunoregulatory functions. In this study we evaluated the effects of protein extracts of probiotics in the amelioration of AR. METHODS: Extracts of Bifidobacterium infantis (EBI) were prepared by lysing the live probiotics. AR mice were developed to be used to evaluate the therapeutic efficacy of EBI. RESULTS: The results show that EBI induced interleukin (IL)-10-producing dendritic cells (DCs) via increasing IL-35 and signal transducer and activator of transcription 3 (STAT3) phosphorylation. IL-10-expressing DCs induced IL-10-producing B cells (B10 cells), with the latter showing immunosuppressive functions. After challenge with specific antigens, AR mice showed sneezing, nasal itch, and increases in serum-specific immunoglobulin E (IgE) and mouse mast cell protease-1; higher levels of T helper 2 (Th2) cytokines (IL-4, 67.17 ± 10.66; IL-5, 62.83 ± 9.70; IL-13, 51.00 ± 6.69, before treatment) in nasal mucosal protein extracts, which were significantly suppressed (IL-4, 27.00 ± 6.66; IL-5, 23.86 ± 4.53; IL-13, 25.67 ± 4.93, after treatment (p < 0.001) by administration with EBI nasal drops. CONCLUSION: EBI can suppress AR via inducing B10 cells. Thus, after carrying out required preclinical experiments and tests, EBI has the translational potential to be used in the treatment of AR and other allergic diseases.

17.
Medicine (Baltimore) ; 98(40): e17445, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31577769

RESUMO

Giant cell tumor (GCT) of bone is a locally aggressive bone tumor, which accounts for 4% to 5% of all primary bone tumors. At present, the early diagnosis and postoperative recurrence monitoring are still more difficult due to the lack of effective biomarkers in GCT. As an effective tool, metabolomics has played an essential role in the biomarkers research of many tumors. However, there has been no related study of the metabolomics of GCT up to now. The purpose of this study was to identify several key metabolites as potential biomarkers for GCT by using nuclear magnetic resonance (NMR)-based metabolic profiles.Patients with GCT in our hospital were recruited in this study and their plasma was collected as the research sample, and plasma collected from healthy subjects was considered as the control. NMR was then utilized to detect all samples. Furthermore, based on correlation coefficients, variable importance for the projection values and P values of metabolites obtained from multidimensional statistical analysis, the most critical metabolites were selected as potential biomarkers of GCT. Finally, relevant metabolic pathways involved in these potential biomarkers were determined by database retrieval, based on which the metabolic pathways were plotted.Finally, 28 GCT patients and 26 healthy volunteers agreed to participate in the study. In the multidimensional statistical analysis, all results showed that there was obvious difference between the GCT group and the control group. Ultimately, 18 metabolites with significant differences met the selection condition, which were identified as potential biomarkers. Through Kyoto Encyclopedia of Genes and Genomes (KEGG) and Human Metabolome Database (HMD) database searching and literature review, these metabolites were found to be mainly correlated with glucose metabolism, fat metabolism, amino acid metabolism, and intestinal microbial metabolism. These metabolic disorders might, in turn, reflect important pathological processes such as proliferation and migration of tumor cells and immune escape in GCT.Our work showed that these potential biomarkers identified appeared to have early diagnostic and relapse monitoring values for GCT, which deserve to be further investigated. In addition, it also suggested that metabolomics profiling approach is a promising screening tool for the diagnosis and relapse monitoring of GCT patients.


Assuntos
Neoplasias Ósseas/diagnóstico , Neoplasias Ósseas/metabolismo , Tumor de Células Gigantes do Osso/diagnóstico , Tumor de Células Gigantes do Osso/metabolismo , Adulto , Biomarcadores/sangue , Estudos de Casos e Controles , Estudos Transversais , Feminino , Humanos , Espectroscopia de Ressonância Magnética , Masculino , Metabolômica , Pessoa de Meia-Idade , Adulto Jovem
18.
Transl Perioper Pain Med ; 6(4): 120-128, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31528664

RESUMO

With chronic opioid use becoming an increasingly common occurrenceamong the general population, perioperative specialties must adapt to the physiologic changes caused by long-term opioids. However, data on the clinicalanesthetics implications of long-term opioid use is scarce. This review intends to survey the literature addressing the molecular mechanisms of long-term opioid use as well as their interaction with various organ systems.

19.
Environ Sci Pollut Res Int ; 26(32): 32790-32803, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31502050

RESUMO

The development of industrial civilization has greatly enriched the material and spiritual life of human beings, but it is accompanied by the intensification of the consumption of earth resources and environmental pollution. The smog that has emerged in various parts of China in recent years is a typical problem, which not only endangers human health but also affects normal human work and life. It is difficult to control smog in a short time productively, so people need to understand the rule of smog formation gradually, and effectively predict the PM2.5 index to help people continuously analyze relevant mechanisms and timely protect-related hazards. This paper proposes a hybrid model that uses the Complementary Ensemble Empirical Modal Decomposition algorithm to mine the information in the original PM2.5 sequence and then predicts the pertinent random forests. The trend of PM2.5 concentration during the decomposition process is effectively reflected, and the decomposition sequence is modeled by the high tolerance of the random forest to the noise data and the good fitting ability. In the modeling process, the parameters are optimized according to the evaluation function of the model on the verification set, and eventually, the prediction sequences are superimposed to obtain the final predicted PM2.5 concentration value. The validity of the model is verified by the data of several Chinese cities with different geographical features in the past 5 years. The results show that the recommendation model is higher than other comparison models in terms of model stability and prediction accuracy.

20.
Molecules ; 24(17)2019 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-31480235

RESUMO

To explore the transformation mechanisms of free gastrodin and combined gastrodin before and after steaming of Gastrodia elata (G. elata), a fresh G. elata sample was processed by the traditional steaming method prescribed by Chinese Pharmacopoeia (2015 version), and HPLC-ESI-TOF/MS method was used to identify the chemical composition in steamed and fresh G. elata. Finally, 25 components were identified in G. elata based on the characteristic fragments of the compounds and the changes of the 25 components of fresh and steamed G. elata were compared by the relative content. Hydrolysis experiments and enzymatic hydrolysis experiments of 10 monomer compounds simulating the G. elata steaming process were carried out for the first time. As a result, hydrolysis experiments proved that free gastrodin or p-hydroxybenzyl alcohol could be obtained by breaking ester bond or ether bond during the steaming process of G. elata. Enzymatic experiments showed that steaming played an important role in the protection of gastrodin, confirming the hypothesis that steaming can promote the conversion of chemical constituents of G. elata-inhibiting enzymatic degradation. This experiment clarified the scientific mechanism of the traditional steaming method of G. elata and provided reference for how to apply G. elata decoction to some extent.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Gastrodia/química , Espectrometria de Massas por Ionização por Electrospray/métodos , Vapor , Álcoois Benzílicos/análise , Glucosídeos/análise , Glucosídeos/química , Hidrólise , Espectrometria de Massas em Tandem
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