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1.
Plant Biotechnol J ; 21(11): 2307-2321, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37626478

RESUMO

Petal senescence is the final stage of flower development. Transcriptional regulation plays key roles in this process. However, whether and how post-transcriptional regulation involved is still largely unknown. Here, we identified an ethylene-induced NAC family transcription factor DcNAP in carnation (Dianthus caryophyllus L.). One allele, DcNAP-dTdic1, has an insertion of a dTdic1 transposon in its second exon. The dTdic1 transposon disrupts the structure of DcNAP and causes alternative splicing, which transcribes multiple domain-deleted variants (DcNAP2 and others). Conversely, the wild type allele DcNAP transcribes DcNAP1 encoding an intact NAC domain. Silencing DcNAP1 delays and overexpressing DcNAP1 accelerates petal senescence in carnation, while silencing and overexpressing DcNAP2 have the opposite effects, respectively. Further, DcNAP2 could interact with DcNAP1 and interfere the binding and activation activity of DcNAP1 to the promoters of its downstream target ethylene biosynthesis genes DcACS1 and DcACO1. Lastly, ethylene signalling core transcriptional factor DcEIL3-1 can activate the expression of DcNAP1 and DcNAP2 in the same way by binding their promoters. In summary, we discovered a novel mechanism by which DcNAP regulates carnation petal senescence at the post-transcriptional level. It may also provide a useful strategy to manipulate the NAC domains of NAC transcription factors for crop genetic improvement.


Assuntos
Dianthus , Syzygium , Dianthus/genética , Syzygium/metabolismo , Flores , Etilenos/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
2.
Environ Res ; 229: 115980, 2023 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-37098386

RESUMO

Accelerated urbanization and industrialization have led to an alarming increase in the generation of wastewater with complex chemical contents. Industrial wastewaters are often a primary source of water contamination. The chemical characterization of different industrial wastewater types is an essential task to interpret the chemical fingerprints of wastewater to identify pollution sources and develop efficient water treatment strategies. In this study, we conduct a non-target chemical analysis for the source characterization of different industrial wastewater samples collected from a chemical industrial park (CIP) located in southeast China. The chemical screening identified volatile and semi-volatile organic compounds that included dibutyl phthalate at a maximum concentration of 13.4 µg/L and phthalic anhydride at 35.9 µg/L. Persistent, mobile, and toxic (PMT) substances among the detected organic compounds were identified and prioritized as high-concern contaminants given their impact on drinking water resources. Moreover, a source analysis of the wastewater collected from the wastewater outlet station indicated that the dye production industry contributed the largest quantities of toxic contaminates (62.6%), and this result was consistent with the ordinary least squares and heatmap results. Thus, our study utilized a combined approach of a non-target chemical analysis, a pollution source identification method, and a PMT assessment of different industrial wastewater samples collected from the CIP. The results of the chemical fingerprints of different industrial wastewater types as well as the results of the PMT assessment benefit risk-based wastewater management and source reduction strategies.


Assuntos
Poluentes Ambientais , Compostos Orgânicos Voláteis , Poluentes Químicos da Água , Poluentes Ambientais/análise , Águas Residuárias , Poluentes Químicos da Água/análise , China
3.
Environ Sci Technol ; 56(23): 17100-17107, 2022 12 06.
Artigo em Inglês | MEDLINE | ID: mdl-36395360

RESUMO

Hazardous air pollutants can be unintentionally and intentionally released in many cases, such as industrial emissions, accidental events, and pesticide application. Under such events, the onsite operation is highly dependent on the molecular composition and spatial distribution of air pollutants in ambient air. However, it is usually difficult for people to reach hazardous and upper sites rapidly. In this work, we designed a new drone-based microextraction sampler array in which a solid-phase microextraction (SPME) fiber was mounted on drones for remote-control sampling at different spaces and was then coupled with a portable gas chromatography-mass spectrometry (PGC-MS) approach for quickly identifying hazardous air pollutants and their spatial distribution in ambient air within minutes. Acceptable analytical performances, including good sensitivity (detection limit at nanogram per liter level), reproducibility (relative standard deviation < 20%, n = 6), analytical speed (single sample within minutes), and excellent linear dynamic response (3 orders of magnitude) were obtained for direct measurement of air samples. The drone-SPME sampling mechanism of air pollutants involving an airflow adsorptive microextraction process was proposed. Overall, this drone-SPME sampling array can access hard-to-reach and dangerous environmental sites and provide air pollution distribution in different spaces, showing versatile potential applications in environmental analysis.


Assuntos
Poluentes Atmosféricos , Microextração em Fase Sólida , Humanos , Microextração em Fase Sólida/métodos , Cromatografia Gasosa-Espectrometria de Massas/métodos , Poluentes Atmosféricos/análise , Reprodutibilidade dos Testes , Dispositivos Aéreos não Tripulados , Monitoramento Ambiental/métodos
4.
J Org Chem ; 86(23): 17265-17273, 2021 12 03.
Artigo em Inglês | MEDLINE | ID: mdl-34792363

RESUMO

A new and practical protocol for the synthesis of medicinally privileged azolo[1,3,5]triazines by simply heating under air has been presented. The in situ generated N-azolo amidines from commercially available aromatic aldehydes and 3-aminoazoles with ammonium iodide undergo the second diamination to accomplish the [3 + 1 + 1 + 1] heteroannulation reaction. This convenient process is appreciated by high efficiency, broad substrate scope, gram-scale synthesis, and operational simplicity under reagent-free conditions.


Assuntos
Aldeídos , Triazinas , Amidinas , Compostos de Amônio , Indicadores e Reagentes
5.
Nanotechnology ; 32(1): 015403, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32947263

RESUMO

Lithium-ion capacitors (LICs) are now drawing increasing attention because of their potential to overcome the current energy limitations of supercapacitors and power limitations of lithium-ion batteries. In this work, we designed LICs by combining an electric double-layer capacitor cathode and a lithium-ion battery anode. Both the cathode and anode are derived from graphene-modified phenolic resin with tunable porosity and microstructure. They exhibit high specific capacity, superior rate capability and good cycling stability. Benefiting from the graphene-enhanced electrode materials, the all graphene-based LICs demonstrate a high working voltage (4.2 V), high energy density of 142.9 Wh kg-1, maximum power density of 12.1 kW kg-1 with energy density of 50 Wh kg-1, and long stable cycling performance (with ∼88% capacity retention after 5000 cycles). Considering the high performance of the device, the cost-effective and facile preparation process of the active materials, this all graphene-based lithium-ion capacitor could have many promising applications in energy storage systems.

6.
Environ Sci Technol ; 55(6): 3593-3603, 2021 03 16.
Artigo em Inglês | MEDLINE | ID: mdl-33656861

RESUMO

Identification of humic-like substances (HULIS) structures and components is still a major challenge owing to their chemical complexity. This study first employed a complementary method with the combination of two-dimensional gas chromatography-time-of-flight mass spectrometry and liquid chromatography-quadrupole-time-of-flight mass spectrometry to address low-polarity and polar components of HULIS in PM2.5 (particulate matter with an aerodynamic diameter less than 2.5 µm), respectively. The combination method showed a significant correlation in identifying overlapping species and performed well in uncovering the chemical complexity of HULIS. A total of 1246 compound species in HULIS (65.6-81.0% for each sample), approximately 1 order of magnitude more compounds than that reported in previous studies, were addressed in PM2.5 collected in real-world household biomass and coal combustion. Aromatics were the most abundant compounds (37.4-64.1% in biomass and 34.5-70.0% in coal samples) of the total mass in all HULIS samples according to carbon skeleton determination, while the major components included phenols (2.6-21.1%), ketones (6.0-17.1%), aldehydes (1.1-6.8%), esters (2.9-20.0%), amines/amides (3.2-8.5%), alcohols (3.8-17.0%), and acids (4.7-15.1%). Among the identified HULIS species, 11-36% mass in biomass and 11-41% in coal were chromophores, while another 22-35 and 23-29% mass were chromophore precursors, respectively. The combination method shows promise for uncovering HULIS fingerprinting.


Assuntos
Poluentes Atmosféricos , Material Particulado , Poluentes Atmosféricos/análise , Biomassa , Carvão Mineral , Monitoramento Ambiental , Substâncias Húmicas/análise , Material Particulado/análise
7.
Anal Chem ; 92(17): 11543-11547, 2020 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-32786499

RESUMO

Molecular analysis of exhaled breath aerosol (EBA) with simple procedures represents a key step in clinical and point-of-care applications. Due to the crucial health role, a face mask now is a safety device that helps protect the wearer from breathing in hazardous particles such as bacteria and viruses in the air; thus exhaled breath is also blocked to congregate in the small space inside of the face mask. Therefore, direct sampling and analysis of trace constituents in EBA using a face mask can rapidly provide useful insights into human physiologic and pathological information. Herein, we introduce a simple approach to collect and analyze human EBA by combining a face mask with solid-phase microextraction (SPME) fiber. SPME fiber was inserted into a face mask to form SPME-in-mask that covered nose and mouth for in vivo sampling of EBA, and SPME fiber was then coupled with direct analysis in real-time mass spectrometry (DART-MS) to directly analyze the molecular compositions of EBA under ambient conditions. The applicability of SPME-in-mask was demonstrated by direct analysis of drugs and metabolites in oral and nasal EBA. The unique features of SPME-in-mask were also discussed. Our results showed that this method is enabled to analyze volatile and nonvolatile analytes in EBA and is expected to have a significant impact on human EBA analysis in clinical applications. We also hope this method will inspire biomarker screening of some respiratory diseases that usually required wearing of a face mask in daily life.


Assuntos
Aerossóis/química , Biomarcadores/análise , Líquidos Corporais/química , Líquidos Corporais/metabolismo , Espectrometria de Massas/métodos , Compostos Orgânicos/análise , Microextração em Fase Sólida/métodos , Técnicas Biossensoriais , Testes Respiratórios , Expiração , Humanos , Imidazóis/química , Técnicas In Vitro , Máscaras , Metabolômica , Manejo de Espécimes/métodos
8.
Org Biomol Chem ; 16(13): 2342-2348, 2018 03 28.
Artigo em Inglês | MEDLINE | ID: mdl-29542779

RESUMO

A facile and efficient [3 + 2 + 1] annulation of aryl methyl ketoxime acetates and triethylamine for the synthesis of 2-methylpyridines was disclosed. This reaction demonstrated that I2 was effective in triggering N-O bond cleavage of oxime acetates generating imine radicals. It was noteworthy that this transformation employed triethylamine as the carbon source for the direct formation of pyridines and introduction of methyl groups.

9.
J Phys Chem A ; 121(25): 4743-4753, 2017 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-28581756

RESUMO

The dissociative photoionization of vinyl chloride (C2H3Cl) in the 11.0-14.2 eV photon energy range was investigated using threshold photoelectron photoion coincidence (TPEPICO) velocity map imaging. Three electronic states, namely, A2A', B2A″, and C2A', of the C2H3Cl+ cation were prepared, and their dissociation dynamics were investigated. A unique fragment ion, C2H3+, was observed within the excitation energy range. TPEPICO three-dimensional time-sliced velocity map images of C2H3+ provided the kinetic energy release distributions (KERD) and anisotropy parameters in dissociation of internal-energy-selected C2H3Cl+ cations. At 13.14 eV, the total KERD showed a bimodal distribution consisting of Boltzmann- and Gaussian-type components, indicating a competition between statistical and non-statistical dissociation mechanisms. An additional Gaussian-type component was found in the KERD at 13.65 eV, a center of which was located at a lower kinetic energy. The overall dissociative photoionization mechanisms of C2H3Cl+ in the B2A″ and C2A' states are proposed based on time-dependent density functional theory calculations of the Cl-loss potential energy curves. Our results highlight the inconsistency of previous conclusions on the dissociation mechanism of C2H3Cl+.

10.
Mol Genet Genomics ; 291(1): 79-92, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26169204

RESUMO

Despite advances by genome-wide association studies (GWAS), much of heritability of common human diseases remains missing, a phenomenon referred to as 'missing heritability'. One potential cause for 'missing heritability' is the rare susceptibility variants overlooked by GWAS. Atrial fibrillation (AF) is the most common arrhythmia seen at hospitals and increases risk of stroke by fivefold and doubles risk of heart failure and sudden death. Here, we studied one large Chinese family with AF and hypertrophic cardiomyopathy (HCM). Whole-exome sequencing analysis identified a mutation in TNNI3, R186Q, that co-segregated with the disease in the family, but did not exist in >1583 controls, suggesting that R186Q causes AF and HCM. High-resolution melting curve analysis and direct DNA sequence analysis were then used to screen mutations in all exons and exon-intron boundaries of TNNI3 in a panel of 1127 unrelated AF patients and 1583 non-AF subjects. Four novel missense variants were identified in TNNI3, including E64G, M154L, E187G and D196G in four independent AF patients, but no variant was found in 1583 non-AF subjects. All variants were not found in public databases, including the ExAC Browser database with 60,706 exomes. These data suggest that rare TNNI3 variants are associated with AF (P = 0.03). TNNI3 encodes troponin I, a key regulator of the contraction-relaxation function of cardiac muscle and was not previously implicated in AF. Thus, this study may identify a new biological pathway for the pathogenesis of AF and provides evidence to support the rare variant hypothesis for missing heritability.


Assuntos
Povo Asiático/genética , Fibrilação Atrial/genética , MAP Quinase Quinase Quinases/genética , Polimorfismo de Nucleotídeo Único/genética , Adolescente , Adulto , Criança , Exoma/genética , Éxons/genética , Feminino , Estudo de Associação Genômica Ampla/métodos , Humanos , Íntrons/genética , Masculino , Pessoa de Meia-Idade , Mutação/genética , Proteínas Serina-Treonina Quinases , Adulto Jovem
11.
Environ Int ; 193: 109072, 2024 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-39461170

RESUMO

The complexity of environmental pollutants poses significant challenges for monitoring and analysis, especially with the emergence of numerous emerging contaminants. Traditional analysis methods rely mainly on laboratory analysis, which involves labor-intensive and time-consuming sample preparation procedures and non-target data analysis, greatly limiting the rapid detection of water organic pollutants. In this study, we designed a robot experimenter combined with GC × GC-TOFMS. By configuring self-developed automated analysis software, we established a fully automated process from sample collection to data characterization, for the analysis of organic pollutants. We validated the method with 111 organic standards compounds. The robot performed 2577 actions covering the entire workflow, from water sample collection to sample pre-treatment. The integration of mass spectrometry and related software enabled the automatic analysis of emerging hazardous contaminants, from sampling to the output of detection results. The results showed the automated process could qualitatively identify all compounds and demonstrated good linearity, low detection limits, and excellent quantitative ability within the range of 0.04-0.4 mg/L. The average recoveries of 82.89 % of the samples ranged from 70 % to 120 % (relative standard deviation (RSD) <15 %) at different spiked concentrations. This indicated that the established method could be used for non-targeted analysis of emerging contaminants in environmental water samples. We applied the method to samples from wastewater treatment plants and river sections, identifying 1,902 compounds across 26 categories, including 6 known hazardous contaminants found in all samples. The relative content of these characteristic compounds will inform whether treated wastewater meets discharge standards and aid in tracing the sources of pollutants. Therefore, the development of this fully automated machine experimental method enables real-time and online automatic analysis of organic pollutants in environmental water. The establishment of characteristic fingerprints can provide technical support for early warning and traceability of water quality.

12.
Virol Sin ; 2024 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-39299564

RESUMO

Oncolytic virus (OV) is increasingly being recognized as a novel vector in cancer immunotherapy. Increasing evidence suggests that OV has the ability to change the immune status of tumor microenvironment, so called transformation of 'cold' tumors into 'hot' tumors. The improved anti-tumor immunity can be induced by OV and further enhanced through the combination of various immunomodulators. The Neo-2/15 is a newly de novo synthesized cytokine that functions as both IL-2 and IL-15. However, it specifically lacks the binding site of IL-2 receptor α subunit (CD25), therefore unable to induce the Treg proliferation. In present study, a recombinant vesicular stomatitis virus expressing the Neo-2/15 (VSVM51R-Neo-2/15) was generated. Intratumoral delivery of VSVM51R-Neo-2/15 efficiently inhibited tumor growth in mice without causing the IL-2-related toxicity previously observed in clinic. Moreover, treatment with VSVM51R-Neo-2/15 increased the number of activated CD8+ T cells but not Treg cells in tumors. More tumor-bearing mice were survival with VSVM51R-Neo-2/15 treatment, and the surviving mice displayed enhanced protection against tumor cell rechallenge due to the induced anti-tumor immunity. In addition, combination therapy of OV and anti-PD-L1 immune checkpoint inhibitors further enhanced the anti-tumor immune response. These findings suggest that our novel VSVM51R-Neo-2/15 can effectively inhibit the tumor growth and enhance the sensitivity to immune checkpoint inhibitors, providing promising attempts for further clinical trials.

13.
J Chromatogr A ; 1726: 464963, 2024 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-38723493

RESUMO

The monitoring of organic compounds in aquatic matrices poses challenges due to its complexity and time-intensive nature. To address these challenges, we introduce a novel approach utilizing a dual-channel mono (1D) and comprehensive two-dimensional (2D) gas chromatography coupled with time-of-flight mass spectrometry (GC × GC-TOFMS) system, integrated with a robotic pretreatment platform, for online monitoring of both volatile organic compounds (VOCs) and semivolatile organic compounds (SVOCs) in water matrices. Employing the robotic platform, we establish a suite of online liquid-liquid extraction (LLE) pretreatment processes for water samples, marking the first instance of such procedures. Leveraging the automatic headspace (HS) module, dual robotic preparations of HS and LLE are sequentially executed to extract VOCs and SVOCs from water matrices. The GC × GC-TOFMS system is distinguished by its dual-channel analytical column configuration, facilitating sequential analysis of VOCs in GC-TOFMS mode and SVOCs in GC × GC-TOFMS mode. Quantitative detection of 55 target VOCs and 104 SVOCs is achieved in a water sample using the instrument system. Our method demonstrates excellent correlation coefficients ranging from 0.990 to 1.000, method detection limits ranging from 0.08 to 4.78 µg L-1, relative standard deviations below 19.3 %, and recovery rates ranging from 50.0 % to 124.0 %. To validate the online monitoring capabilities of our system, we assess target SVOCs at three different concentration levels over a 3-day period. Most compounds exhibit recovery rates ranging from 70.0 % to 130.0 %. Furthermore, we apply our method to analyze a real water sample, successfully identifying over 100 target and nontarget VOCs/SVOCs, including alcohols, aldehydes, ketones, acids, esters, and phenols. These results highlight the efficacy of the proposed analysis system, capable of conducting two distinct analyses in automatic sequence, thereby enhancing the efficiency and accuracy of organic compound analysis in water matrices.


Assuntos
Cromatografia Gasosa-Espectrometria de Massas , Extração Líquido-Líquido , Robótica , Compostos Orgânicos Voláteis , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/isolamento & purificação , Cromatografia Gasosa-Espectrometria de Massas/métodos , Extração Líquido-Líquido/métodos , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/isolamento & purificação , Limite de Detecção
14.
Talanta ; 272: 125767, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38428128

RESUMO

Herein, polysiloxane-based aggregation-induced emission (AIE) polymers and rubbers were prepared which display interesting multi-stimuli responsive fluorescence. TPE-modified polydimethylsiloxanes (PDMS-TPE) as polysiloxane-based AIE polymers were synthesized through Heck reaction of bromo-substituted tetraphenylethene (TPE-Br) and vinyl polysiloxanes. As expected, TPE moiety endows the modified polysiloxane with typical AIE behavior. However, limited by the long polymer chains, the aggregation process of PDMS-TPE shows obvious differences compared with the small molecule TPE-Br. The fluorescence of PDMS-TPE in THF/H2O starts to increase when the H2O fraction (fw) is 70% while TPE-Br is nearly non-luminous until the fw is up to 99%. The fluorescence intensity ratio (I/I0) of PDMS-TPE in the aggregated state and dispersed state is over 1300, greater than that of TPE-Br (I/I0 = 380). More importantly, the exceptional thermal motion of Si-O-Si chains and AIE characteristic of TPE moiety work together, enabling PDMS-TPE to show specific temperature-dependent fluorescence with a wider response range of room temperature to 190°C, which is distinguished from TPE-Br. And such fluorescence responsiveness possess good fatigue-resistance. Furthermore, fluorescent silicone rubbers, r-PDMS-TPE were prepared by using PDMS-TPE as additive of the base gum. They display interesting solvent-controllable fluorescence and higher tensile strength (4.42 MPa) than the control sample without TPE component (1.96 MPa). Notably, a unique stretching-enhanced emission (SEE) phenomenon is observed from these TPE-modified silicone rubbers. When being stretched, the rubbers' fluorescent emission intensity could increase by 143%.

15.
Nat Commun ; 15(1): 385, 2024 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-38195636

RESUMO

Exploring the dynamic structural evolution of electrocatalysts during reactions represents a fundamental objective in the realm of electrocatalytic mechanism research. In pursuit of this objective, we synthesized PhenPtCl2 nanosheets, revealing a N2-Pt-Cl2 coordination structure through various characterization techniques. Remarkably, the electrocatalytic performance of these PhenPtCl2 nanosheets for hydrogen evolution reaction (HER) surpasses that of the commercial Pt/C catalyst across the entire pH range. Furthermore, our discovery of the dynamic coordination changes occurring in the N2-Pt-Cl2 active sites during the electrocatalytic process, as clarified through in situ Raman and X-ray photoelectron spectroscopy, is particularly noteworthy. These changes transition from Phen-Pt-Cl2 to Phen-Pt-Cl and ultimately to Phen-Pt. The Phen-Pt intermediate plays a pivotal role in the electrocatalytic HER, dynamically coordinating with Cl- ions in the electrolyte. Additionally, the unsaturated, two-coordinated Pt within Phen-Pt provides additional space and electrons to enhance both H+ adsorption and H2 evolution. This research illuminates the intricate dynamic coordination evolution and structural adaptability of PhenPtCl2 nanosheets, firmly establishing them as a promising candidate for efficient and tunable electrocatalysts.

16.
J Chem Phys ; 138(9): 094306, 2013 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-23485293

RESUMO

Dissociation of internal energy selected CF4(+) ions in an excitation energy range of 15.40-19.60 eV has been investigated using threshold photoelectron-photoion coincidence (TPEPICO) velocity imaging. Only CF3(+) fragment ions are observed in coincident mass spectra, indicating all the X(2)T1, A(2)T2, and B(2)E ionic states of CF4(+) are fully dissociative. Both kinetic energy released distribution (KERD) and angular distribution in dissociation of CF4(+) ions have been derived from three-dimensional TPEPICO time-sliced images. A parallel distribution of CF3(+) fragments along the polarization vector of photon is observed for dissociation of CF4(+) ions in all the low-lying electronic states. With the aid of F-loss potential energy curves, dissociation mechanisms of CF4(+) ions in these electronic states have been proposed. CF4(+) ions in both X(2)T1 and A(2)T2 states directly dissociate to CF3(+) and F fragments along the repulsive C-F coordinate, while a two-step dissociation mechanism is suggested for B(2)E state: CF4(+)(B(2)E) ion first converts to the lower A(2)T2 state via internal conversion, then dissociates to CF3(+) and F fragments along the steep A(2)T2 potential energy surface. In addition, an adiabatic appearance potential of AP0(CF3(+)∕CF4) has also been established to be 14.71 ± 0.02 eV, which is very consistent with the recent calculated values.

17.
Food Res Int ; 169: 112819, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37254394

RESUMO

To investigate the main aroma-active volatiles out from comprehensive chemical profile, we proposed an aroma correlation assisted volatilome coupled network analysis strategy and applied it to the study of Rosa roxburghii. Based on 475 detected volatiles with GC × GC-TOF/MS analysis, the volatilome was screened with both positive aroma activities and high contents to discover some aliphatic acids, alcohols, aldehydes and esters, terpenoids as well as some alkenes and ketones. Especially, a series of homologous C6- and C8- acids, alcohols, aldehydes, esters as well as some terpenoids like limonene take the predominant contributions to the aromas. Moreover, two aroma-active and aroma-contributing volatile groups including acid-aldehyde-alcohol-ester and terpenoid groups were clustered to integrally be responsible for the major aromas of R. roxburghii with network analysis. Additionally, the accumulation of C6- and C8-family homologous aliphatic volatiles was also elucidated with linoleic and linolenic acid derived pathways. This strategy is practical to investigate the main aroma-active volatiles based on volatilome.


Assuntos
Rosa , Compostos Orgânicos Voláteis , Odorantes/análise , Compostos Orgânicos Voláteis/análise , Terpenos , Etanol , Aldeídos/análise , Ácidos , Ésteres/análise
18.
J Phys Chem A ; 116(38): 9459-65, 2012 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-22946501

RESUMO

Direct experimental evidence for dissociative photoionization of oxygen molecule via the (2)Σ(u)(-) ionic optical dark state is presented by an investigation using the method of threshold photoelectron-photoion coincidence (TPEPICO) velocity imaging. Besides vibrational progress of the B(2)Σ(g)(-) state, several weak vibrational bands of the (2)Σ(u)(-) ionic optical dark state are observed concomitantly in an excitation energy range of 20.2-21.1 eV. Only O(+) fragments are detected in the whole excitation energy range; therefore, all vibrational bands are completely predissociative. TPEPICO three-dimensional time-sliced velocity images of O(+) fragments dissociated from vibrational state-selected O(2)(+)((2)Σ(u)(-),v(+)) ions are recorded. For the (2)Σ(u)(-)(v(+)=0-3) vibrational states, only the lowest dissociation channel of O(+)((4)S) + O((3)P) is observed. Once the photon energy is slightly increased to the (2)Σ(u)(-)(v(+)=4) level, a new concentric doughnut appears in the image, indicating that the second dissociation channel of O(+)((4)S) + O((1)D) is identified indeed. With the aid of potential energy curves, the dissociative mechanism of O(2)(+) in the (2)Σ(u)(-)(v(+)) state is proposed.


Assuntos
Oxigênio/química , Íons/química , Processos Fotoquímicos , Vibração
19.
J Chem Phys ; 136(3): 034304, 2012 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-22280757

RESUMO

Utilizing threshold photoelectron-photoion coincidence (TPEPICO) velocity imaging, dissociation of state-selected CH(3)Cl(+) ions was investigated in the excitation energy range of 11.0-18.5 eV. TPEPICO time-of-flight mass spectra and three-dimensional time-sliced velocity images of CH(3)(+) dissociated from CH(3)Cl(+)(A(2)A(1) and B(2)E) ions were recorded. CH(3)(+) was kept as the most dominant fragment ion in the present energy range, while the branching ratio of CH(2)Cl(+) fragment was very low. For dissociation of CH(3)Cl(+)(A(2)A(1)) ions, a series of homocentric rings was clearly observed in the CH(3)(+) image, which was assigned as the excitation of umbrella vibration of CH(3)(+) ions. Moreover, a dependence of anisotropic parameters on the vibrational states of CH(3)(+)(1(1)A') provided a direct experimental evidence of a shallow potential well along the C-Cl bond rupture. For CH(3)Cl(+)(B(2)E) ions, total kinetic energy released distribution for CH(3)(+) fragmentation showed a near Maxwell-Boltzmann profile, indicating that the Cl-loss pathway from the B(2)E state was statistical predissociation. With the aid of calculated Cl-loss potential energy curves of CH(3)Cl(+), CH(3)(+) formation from CH(3)Cl(+)(A(2)A(1)) ions was a rapid direct fragmentation, while CH(3)Cl(+)(B(2)E) ions statistically dissociated to CH(3)(+) + Cl via internal conversion to the high vibrational states of X(2)E.


Assuntos
Cloreto de Metila/química , Cinética , Espectrometria de Massas , Processos Fotoquímicos , Espectroscopia Fotoeletrônica , Vibração
20.
J Healthc Eng ; 2022: 2203737, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35340253

RESUMO

Neurons refer to nerve cells. Each neuron is connected with thousands of other neurons to form a corresponding functional area and carry out complex communication with other functional areas. Its importance to the human body is self-evident. There are also many scholars studying the mechanism of apoptosis. This paper proposes a study of neuronal apoptosis in patients with liver cirrhosis and neuronal epileptiform discharge models based on multi-modal fusion deep learning, aiming to study the influencing factors of abnormal neuronal discharge in the brain. The method in this paper is to study multi-modal information fusion methods, perform Bayesian inference, and analyze multi-modal medical data. The function of these research methods is to obtain the relationship between the independence of information and the intersection of information among modalities. In the neuronal epileptiform discharge model, the mRNA expression level of the necroptotic signaling pathway related protein was detected, and the mechanism of neuronal necrosis in patients with liver cirrhosis was explored. Experiments show that the neuron recognition rate has been increased from 67.2% to 84.5%, and the time has been reduced, proving the effectiveness of deep learning.


Assuntos
Aprendizado Profundo , Apoptose , Teorema de Bayes , Humanos , Cirrose Hepática , Neurônios
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