Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 45
Filtrar
Mais filtros

Bases de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Nat Methods ; 21(4): 609-618, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38443507

RESUMO

Precise identification and quantification of amino acids is crucial for many biological applications. Here we report a copper(II)-functionalized Mycobacterium smegmatis porin A (MspA) nanopore with the N91H substitution, which enables direct identification of all 20 proteinogenic amino acids when combined with a machine-learning algorithm. The validation accuracy reaches 99.1%, with 30.9% signal recovery. The feasibility of ultrasensitive quantification of amino acids was also demonstrated at the nanomolar range. Furthermore, the capability of this system for real-time analyses of two representative post-translational modifications (PTMs), one unnatural amino acid and ten synthetic peptides using exopeptidases, including clinically relevant peptides associated with Alzheimer's disease and cancer neoantigens, was demonstrated. Notably, our strategy successfully distinguishes peptides with only one amino acid difference from the hydrolysate and provides the possibility to infer the peptide sequence.


Assuntos
Nanoporos , Aminoácidos/química , Peptídeos/química , Sequência de Aminoácidos , Porinas/química , Porinas/metabolismo
2.
Phys Chem Chem Phys ; 25(42): 29098-29107, 2023 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-37862024

RESUMO

Electrical control of magnetism is of great interest for low-energy-consumption spintronic applications. Due to the recent experimental breakthrough in two-dimensional materials, with the absence of hanging bonds on the surface and strong tolerance for lattice mismatch, heterogeneous integration of different two-dimensional materials provides a new opportunity for coupling between different physical properties. Here, we report the realization of nonvolatile magnetoelectric coupling in vdW sandwich heterostructure CuInP2S6/MnCl3/CuInP2S6. Using first-principles calculations, we reveal that when interfacing with ferroelectric CuInP2S6, the Dirac half-metallic state of monolayer MnCl3 will be destroyed. Moreover, depending on the electrically polarized direction of CuInP2S6, MnCl3 can be a half-metal or a ferromagnetic semiconductor. We unveil that the obtained ferromagnetic semiconductor in MnCl3 can be attributed to the different gain and loss of electrons on the two adjacent Mn atoms due to the sublattice symmetry broken by interlayer coupling. The effects of interfacial magnetoelectric coupling on magnetic anisotropy and ferromagnetic Curie temperature of MnCl3 are also investigated, and a multiferroic memory based on this model is designed. Our work not only provides a promising way to design nonvolatile electrical control of magnetism but also renders monolayer MnCl3 an appealing platform for developing low-dimensional memory devices.

3.
Environ Res ; 209: 112806, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35101403

RESUMO

To prevent the Corona Virus Disease 2019 (COVID-19) spreading, Chinese government takes a series of corresponding measures to restrict human mobility, including transportation lock-down and industries suspension, which significantly influenced the ambient air quality and provided vary rare time windows to assess the impacts of anthropological activities on air pollution. In this work, we divided the studied timeframe (2019/12/24-2020/2/24) into four periods and selected 88 cities from 31 representative urban agglomerations. The indicators of PM2.5/PM10 and NO2/SO2 were applied, for the first time, to analyze the changes in stoichiometric characteristics of ambient air pollutants pre-to post-COVID-19 in China. The results indicated that the ratios of NO2/SO2 presented a responding decline, especially in YRD (-5.01), YH (-3.87), and MYR (-3.84), with the sharp reduction of traffic in post-COVID-19 periods (P3-P4: 2.34 ± 0.94 m/m) comparing with pre-COVID-19 periods (P1-P2: 4.49 ± 2.03 m/m). Whereas the ratios of PM2.5/PM10 increased in P1-P3, then decreased in P4 with relatively higher levels (>0.5) in almost all urban agglomerations. Furthermore, NO2 presented a stronger association with PM2.5/PM10 variation than CO; and PM2.5 with NO2/SO2 variation than PM10. In summary, the economic structure, lockdown measures and meteorological conditions could explain the noteworthy variations in different urban agglomerations. These results would be in great help for improving air quality in the post-epidemic periods.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , COVID-19 , Poluentes Ambientais , Poluentes Atmosféricos/análise , Poluição do Ar/análise , COVID-19/epidemiologia , China/epidemiologia , Cidades/epidemiologia , Controle de Doenças Transmissíveis , Monitoramento Ambiental , Humanos , Material Particulado/análise
4.
Sensors (Basel) ; 22(4)2022 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-35214562

RESUMO

For conventional near-infrared spectroscopy (NIR) technology, even within the same sample, the NIR spectral signal can vary significantly with variation of spectrometers and the spectral collection environment. In order to improve the applicability and application of NIR prediction models, effective calibration transfer is essential. In this study, a stability-analysis-based feature selection algorithm (SAFS) for NIR calibration transfer is proposed, which is used to extract effective spectral band information with high stability between the master and slave instruments during the calibration transfer process. The stability of the spectrum bands shared between the master and slave instruments is used as the evaluation index, and the genetic algorithm was used to select suitable thresholds to filter out the spectral feature information suitable for calibration transfer. The proposed SAFS algorithm was applied to two near-infrared datasets of corn oil content and larch wood density. Simultaneously, its calibration transfer performances were compared with two classical feature selection methods. The effects of different preprocessing algorithms and calibration transfer algorithms were also assessed. The model with the feature variables selected by the SAFS obtained the best prediction. The SAFS algorithm can simplify the spectral data to be transferred and improve the transfer efficiency, and the universality of the SAFS allows it to be used to optimize calibration transfer in various situations. By combining different preprocessing and classic feature selection methods with this, the sensitivity of the correlation between spectral data and component information are improved significantly, as well as the effect of calibration transfer, which will be deeply developed.


Assuntos
Algoritmos , Espectroscopia de Luz Próxima ao Infravermelho , Calibragem , Análise dos Mínimos Quadrados , Espectroscopia de Luz Próxima ao Infravermelho/métodos
5.
Anal Chem ; 93(41): 13861-13869, 2021 10 19.
Artigo em Inglês | MEDLINE | ID: mdl-34506117

RESUMO

Accurate, specific, and inexpensive detection of multiple infectious pathogens simultaneously is a significant goal for human health and safety. Herein we present a rationally designed modular DNA circuit for point-of-care (POC) detection of a variety of infectious pathogens based on nucleic acid isothermal amplification technology and DNAzyme-mediated colorimetric readout. A modular DNA circuit was constructed with a fixed module and a flexible module and was rationally designed according to genetic targets. On this basis, the platform could detect multiple genetic targets corresponding to infectious pathogens simultaneously. Signal amplification properties of the DNA circuit and the peroxidase-like DNAzyme enable the detection limits to reach the picomolar level. By urea treatment and magnetic separation, the fixed module can be reused at least five times, which makes this assay more economical and environmentally friendly. The detection of genetic infectious pathogens should be accomplished in 2 h with naked-eye observation and may provide an efficient tool for POC analysis of multiple infectious pathogens, especially in resource-poor areas.


Assuntos
Técnicas Biossensoriais , DNA Catalítico , Colorimetria , DNA/genética , Humanos , Técnicas de Amplificação de Ácido Nucleico , Sistemas Automatizados de Assistência Junto ao Leito
6.
Acc Chem Res ; 53(11): 2648-2658, 2020 11 17.
Artigo em Inglês | MEDLINE | ID: mdl-33090765

RESUMO

Silica-alumina catalysts, including zeolites and amorphous silica-aluminas (ASAs), are among the most widely used solid acid catalysts and supports to produce petrochemicals, fine chemicals, and renewable energy. The coordination, distribution, and interactions of aluminum in ASAs have an enormous impact on their acidic properties and catalytic performance. Unsaturated tetracoordinated aluminum (AlIV) species are commonly accepted as the key sites in generating catalytically active Brønsted acid sites (BASs) in silica-alumina catalysts. Extensive efforts focus on increasing the concentration of AlIV as the main route to enhance their Brønsted acidity for efficient catalysis. However, increasing the AlIV concentration either weakens the acid strength in zeolites or lowers Brønsted acidity in ASAs at high Al/Si ratios, impeding acidity enhancement of these popular catalysts."Pentacoordinated aluminum (AlV) species" are potential unsaturated Al species like AlIV but rarely observed in silica-aluminas, and thus, are widely considered unavailable for BAS formation or surface reactions. In this Account, we will describe novel strategies for the controlled synthesis of AlV-enriched ASAs using flame-spray pyrolysis (FSP) techniques and highlight the contribution of AlV species in acidity enhancement, together with their structure-activity relationship in the conversion of biomass-derived compounds into valuable chemicals. Using various in situ and advanced 2D solid-state NMR (SSNMR) experiments, the studies of the acidic properties and local structure of AlV-enriched ASAs reveal that AlV species can highly populate on ASA surfaces, promote BASs formation, and facilitate adaptable tuning of BASs from moderate to zeolitic strength by synergy with neighboring Al sites. Moreover, the BASs with enhanced acidity can work jointly with surface Lewis acid sites or metal active species for bifunctional catalysis on AlV-enriched ASAs. Compared to zeolites, these AlV-enriched ASAs are highly active in acid-catalyzed biomass conversion, including alcohol dehydration and sugar conversion reactions, as well as in promoting the performance of supported metal catalysts in chemoselective hydrogenation of aromatic ketones. These new insights provide a state-of-the-art strategy for strongly enhancing the acidity of these popular silica-alumina catalysts, which offers an interesting potential for a wide range of acid and multifunctional catalysis.

7.
Environ Sci Technol ; 55(8): 5422-5434, 2021 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-33720690

RESUMO

Conventional Cu-ZSM-5 and special Cu-ZSM-5 catalysts with diverse morphologies (nanoparticles, nanosheets, hollow spheres) were synthesized and comparatively investigated for their performances in the selective catalytic reduction (SCR) of NO to N2 with ammonia. Significant differences in SCR behavior were observed, and nanosheet-like Cu-ZSM-5 showed the best SCR performance with the lowest T50 of 130 °C and nearly complete conversion in the temperature range of 200-400 °C. It was found that Cu-ZSM-5 nanosheets [mainly exposed (0 1 0) crystal plane] with abundant mesopores and framework Al species were favorable for the formation of high external surface areas and Al pairs, which influenced the local environment of Cu. This motivated the preferential formation of active copper species and the rapid switch between Cu2+ and Cu+ species during NH3-SCR, thus exhibiting the highest NO conversion. In situ diffused reflectance infrared Fourier transform spectroscopy (DRIFTS) results indicated that the Cu-ZSM-5 nanosheets were dominated by the Eley-Rideal (E-R) mechanism and the labile nitrite species (NH4NO2) were the crucial intermediates during the NH3-SCR process, while the inert nitrates were more prone to generate on Cu-ZSM-5 nanoparticles and conventional one. The combined density functional theory (DFT) calculations revealed that the decomposition energy barrier of nitrosamide species (NH2NO) on the (0 1 0) crystal plane of Cu-ZSM-5 was lower than those on (0 0 1) and (1 0 0) crystal planes. This study provides a strategy for the design of NH3-SCR zeolite catalysts.


Assuntos
Amônia , Zeolitas , Catálise , Cobre , Oxirredução
8.
Phys Chem Chem Phys ; 21(35): 19529-19537, 2019 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-31463497

RESUMO

In spite of the widespread applications of amorphous silica-aluminas (ASAs) in many important industrial chemical processes, their high-resolution structures have remained largely elusive. Specifically, the lack of long-range ordering in ASA precludes the use of diffraction methods while NMR spectroscopy has been limited by low sensitivity. Here, we use conventional as well as DNP-enhanced 29Si-29Si, 27Al-27Al, and 29Si-27Al solid-state NMR experiments to shed light on the ordering of atoms in ASAs prepared by flame-spray-pyrolysis. These experiments, in conjunction with a novel Monte Carlo-based approach to simulating RESPDOR dephasing curves, revealed that ASA materials obey Loewenstein's rule of aluminum avoidance. 3D 17O{1H} and 2D 17O{1H,27Al} experiments were developed to measure site-specific O-H and HO-Al distances, and show that the Brønsted acid sites originate predominantly from the pseudo-bridging silanol groups.

9.
Med Sci Monit ; 25: 5181-5190, 2019 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-31299041

RESUMO

BACKGROUND MicroRNA-381 (miR-381) is proven to be involved in many human tumors. Bioinformatics prediction suggests that miR-381 is decreased in renal cell carcinoma. However, its biological functions in clear-cell renal cell carcinoma (ccRCC) remain largely unknown. The present research aimed to evaluate miR-381 expression in renal cancer tissues and its effects on cell proliferation, growth, migration, and chemoresistance. MATERIAL AND METHODS Sixty pairs of ccRCC and the adjacent non-tumor specimens were collected during routine therapeutic surgery. Quantitative real-time PCR (qRT-PCR) assay was employed to examine miR-381 expression in the ccRCC tissues and the associated adjacent tissues (the normal tissues adjacent to tumor tissues). Cell transfection assay and Thiazolyl Blue Tetrazolium Bromide (MTT) assay were utilized to observe effects of miR-381 on the cell proliferation, growth, invasion, and chemoresistance in the Caki-1 cell line and 786-O cell line. Flow cytometry was used to assess cell apoptosis. Caki-1 cell and 786-O cell Xenograft BALB/c mouse models were established. RESULTS miR-381 expression was downregulated in ccRCC tissues in vivo and in cell lines in vitro. Downregulation of miR-381 promoted growth of cells and restrained the ccRCC cell apoptosis. Increased miR-381 combined with Ci and Pa suppressed the proliferation and enhanced the anti-tumor effects of Ci and Pa at tolerated concentrations in vitro. miR-381 inhibition promoted chemoresistance in vitro. CONCLUSIONS miR-381 levels were significantly downregulated in renal cancer tissues and miR-381 inhibition promoted tumor cell growth, migration, and chemoresistance.


Assuntos
Carcinoma de Células Renais/genética , Neoplasias Renais/genética , MicroRNAs/antagonistas & inibidores , Idoso , Idoso de 80 Anos ou mais , Animais , Apoptose/genética , Carcinoma de Células Renais/metabolismo , Carcinoma de Células Renais/patologia , Ciclo Celular/genética , Processos de Crescimento Celular/genética , Movimento Celular/genética , Regulação para Baixo , Resistencia a Medicamentos Antineoplásicos , Feminino , Humanos , Neoplasias Renais/metabolismo , Neoplasias Renais/patologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , MicroRNAs/genética , MicroRNAs/metabolismo , Pessoa de Meia-Idade , Ensaios Antitumorais Modelo de Xenoenxerto
10.
Angew Chem Int Ed Engl ; 58(50): 18061-18068, 2019 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-31592563

RESUMO

Commercial bioethanol can be readily converted into ethylene by a dehydration process using solid acids, such as Brønsted acidic H-ZSM-5 zeolites, and thus, it is an ideal candidate to replace petroleum and coal for the sustainable production of ethylene. Now, strong Lewis acidic extra-framework three-coordinate Al3+ species were introduced into H-ZSM-5 zeolites to improve their catalytic activity. Remarkably, Al3+ species working with Brønsted acid sites can accelerate ethanol dehydration at a much lower reaction temperature and shorten the unsteady-state period within 1-2 h, compared to >9 h for those without Al3+ species, which can significantly enhance the ethanol dehydration efficiency and reduce the cost. The reaction mechanism, studied by solid-state NMR, shows that strong Lewis acidic EFAl-Al3+ species can collaborate with Brønsted acid sites and promote ethanol dehydration either directly or indirectly via an aromatics-based cycle to produce ethylene.

11.
Tumour Biol ; 39(6): 1010428317709990, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28639914

RESUMO

To investigate the diagnostic value of urothelial carcinoma-associated 1 as a urine biomarker in urinary bladder cancer patients by performing a comprehensive meta-analysis. A comprehensive literature search was conducted by the databases PubMed, Embase, Cochrane Library, China Knowledge Resource Integrated, and Web of Science. The quality of eligible studies was scored with the Quality Assessment of Diagnostic Accuracy Studies. The bivariate meta-analysis model was used to pool the sensitivity, specificity, likelihood ratio, and diagnostic odds ratio. Receiver operating characteristic curves and hierarchical summary receiver operating characteristic models were employed to check the overall test performance in this meta-analysis. Seven publications involving 678 patients and 563 controls were included in this meta-analysis. The pooled sensitivity was 0.84 (95% confidence interval: 0.80-0.88), specificity was 0.87 (95% confidence interval: 0.75-0.94), positive likelihood ratio was 6.5 (95% confidence interval: 3.10-13.62), negative likelihood ratio was 0.18 (95% confidence interval: 0.13-0.25), and diagnostic odds ratio was 36 (95% confidence interval: 13-99). The area under the summary receiver operating characteristic curve was 0.89 (95% confidence interval: 0.86-0.91). Our results indicated that urothelial carcinoma-associated 1 was a potential diagnostic biomarker with good specificity and sensitivity in urinary bladder cancer. Further prospective studies with larger cohorts are necessary to evaluate the diagnostic accuracy of urothelial carcinoma-associated 1 for urinary bladder cancer.


Assuntos
Biomarcadores Tumorais/urina , Carcinoma de Células de Transição/urina , RNA Longo não Codificante/urina , Neoplasias da Bexiga Urinária/urina , Carcinoma de Células de Transição/patologia , Regulação Neoplásica da Expressão Gênica , Humanos , Prognóstico , Neoplasias da Bexiga Urinária/patologia
12.
Immunogenetics ; 67(8): 447-61, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26129855

RESUMO

Although immune pressure exerted by MHC class I-restricted cytotoxic T lymphocytes (CTL) are an important determinant of outcome in pathogenic HIV and SIV infection, lack of data on MHC class I genes has hampered study of its role in natural hosts with nonpathogenic SIV infection. In this study, we cloned and characterized full-length MHC class I genes derived from the cDNA library of two unrelated naturally infected sooty mangabeys (Cercocebus atys) in whom SIV-specific CTL epitopes were previously mapped. Twenty one full-length MHC class I alleles consisting of five MHC-A (Ceat-A), 13 MHC-B (Ceat-B), and three MHC-E (Ceat-E) alleles were identified. Sequence-specific primers (SSP) for high-throughput screening of genomic DNA by PCR were developed for 16 of the 18 Ceat-A and Ceat-B alleles. Screening of 62 SIV-negative and 123 SIV-infected sooty mangabeys at the Yerkes National Primate Research Center (YNPRC) revealed the presence of up to four MHC-A and eight MHC-B alleles in individual mangabeys, indicating that similar to macaque species, mangabeys have at least two duplications of the MHC-A locus and four duplications of the MHC-B locus in the absence of an MHC-C locus. Using stable transfectants of Ceat MHC Class I alleles in the MHC-null 721.221 cell line, we identified Ceat-B*12:01 as the restricting allele of a previously reported Nef20-28 CTL epitope. Ceat-B*1201/Nef20-28 tetramers identified tetramer-positive CD8+ T lymphocytes in Ceat-B*1201-positive SIV-infected mangabeys. This study has laid the groundwork for comprehensive analysis of CTL and SIV evolution in a natural host of SIV infection.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Cercocebus atys/genética , Epitopos de Linfócito T/genética , Antígenos de Histocompatibilidade Classe I/genética , Imunidade Celular/imunologia , Síndrome de Imunodeficiência Adquirida dos Símios/imunologia , Vírus da Imunodeficiência Símia/imunologia , Linfócitos T Citotóxicos/imunologia , Alelos , Sequência de Aminoácidos , Animais , Dados de Sequência Molecular , Filogenia , Reação em Cadeia da Polimerase , Homologia de Sequência de Aminoácidos , Síndrome de Imunodeficiência Adquirida dos Símios/virologia
13.
J Immunol ; 186(9): 5151-61, 2011 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-21441446

RESUMO

Although the cellular immune response is essential for controlling SIV replication in Asian macaques, its role in maintaining nonpathogenic SIV infection in natural hosts such as sooty mangabeys (SM) remains to be defined. We have previously shown that similar to rhesus macaques (RM), SM are able to mount a T lymphocyte response against SIV infection. To investigate early control of SIV replication in natural hosts, we performed a detailed characterization of SIV-specific cellular immunity and viral control in the first 6 mo following SIV infection in SM. Detection of the initial SIV-specific IFN-γ ELISPOT response in SIVsmE041-infected SM coincided temporally with a decline in peak plasma viremia and was similar in magnitude, specificity, and breadth to SIVsmE041-infected and SIVmac239-infected RM. Despite these similarities, SM showed a greater reduction in postpeak plasma viremia and a more rapid disappearance of productively SIV-infected cells from the lymph node compared with SIVmac239-infected RM. The early Gag-specific CD8(+) T lymphocyte response was significantly more polyfunctional in SM compared with RM, and granzyme B-positive CD8(+) T lymphocytes were present at significantly higher frequencies in SM even prior to SIV infection. These findings suggest that the early SIV-specific T cell response may be an important determinant of lymphoid tissue viral clearance and absence of lymph node immunopathology in natural hosts of SIV infection.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Linfonodos/imunologia , Linfonodos/virologia , Síndrome de Imunodeficiência Adquirida dos Símios/imunologia , Vírus da Imunodeficiência Símia/imunologia , Animais , Separação Celular , Cercocebus atys , Citometria de Fluxo , Hibridização In Situ , RNA Viral/sangue , Síndrome de Imunodeficiência Adquirida dos Símios/sangue , Síndrome de Imunodeficiência Adquirida dos Símios/virologia , Viremia/sangue
14.
Front Chem ; 11: 1225073, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37927567

RESUMO

The global annual production of rice is over 750 million tons, and generates a huge amount of biomass waste, such as straw, husk, and bran, making rice waste an ideal feedstock for biomass conversion industries. This review focuses on the current progress in the transformation of rice waste into valuable products, including biochar, (liquid and gaseous) biofuels, valuable chemicals (sugars, furan derivatives, organic acids, and aromatic hydrocarbons), and carbon/silicon-based catalysts and catalyst supports. The challenges and future prospectives are highlighted to guide future studies in rice waste valorization for sustainable production of fuels and chemicals.

15.
Environ Int ; 179: 108179, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37666041

RESUMO

Carbonaceous aerosols, comprising organic carbon (OC) and elemental carbon (EC), are critical component of fine particulate matter (PM2.5), with diverse impacts on air quality and human health. This study investigated the concentrations and seasonal patterns of carbonaceous species in PM2.5 during both the heating season (January 2021) and non-heating season (July 2021) in three coal-fueled cities in northern China, as well as the differences in carbonaceous aerosols and their associations with socioeconomic parameters in cities situated on either side of the "Hu Line" in China. The results showed that, owing to intensified coal combustion and unfavorable meteorological conditions, levels of OC, EC, and OC/EC ratios were higher in winter compared to summer. Moreover, the presence of dust (DU) and light pollution (LP) days resulted in elevated OC levels but decreased EC levels. The Char-EC/Soot-EC ratios were highest during LP, followed by CL and DU. A source apportionment analysis demonstrated that coal burning, vehicle exhaust, road dust, and biomass burning were the primary contributors to carbonaceous aerosols, as confirmed by diagnostic ratios, Char-EC/Soot-EC ratios, and PCA analysis. Furthermore, our study found that carbonaceous aerosols concentrations and source apportionment primarily varied with diurnal and seasonal trends and different pollution types. Additionally, at the national scale, population density and urban green space exhibited a positive correlation with OC/EC ratios (p < 0.05), while energy consumption per unit of GDP showed a negative correlation (p < 0.05). The observation that OC/EC ratios were lower in coal-fueled cities than in economy-based cities suggests a more severe pollution scenario. These findings highlight the importance of comprehending of the seasonal variation and chemical characteristics of carbonaceous aerosol for understanding air pollution sources and characteristics, which is essential for both air quality management and human health.


Assuntos
Poeira , Fuligem , Humanos , Estações do Ano , Cidades , Aerossóis , Carbono , Carvão Mineral , Material Particulado , Fatores Socioeconômicos
16.
PLoS One ; 18(8): e0288911, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37561734

RESUMO

In this study, the influences of mulberry leaf extract (MLE) addition on the physicochemical properties including the specific volume, texture and sensory features of white bread (WB) were evaluated by the sensory analysis technology. A double-blind, randomised, repeat-measure design was used to study the impact of MLE addition on the postprandial blood glucose response as well as the satiety index of WB. Results showed that the addition of MLE showed no significant effects on the physicochemical properties of WB except for the slight changes of color and bitterness. The addition of MLE significantly reduced the total blood glucose rise after ingestion of WB over 120 minutes, and reduced the GI value of WB in a dose-effect relationship. When the concentration of MLE reached 1.5 g per 100 g available carbohydrate, the GI value of WB could be reduced from 77 to 43. This study provides important information in terms of the appropriateness of MLE when added to more complex real food, the dose-dependent relationship could supply a reference for the application of MLE.


Assuntos
Pão , Índice Glicêmico , Morus , Extratos Vegetais , Glicemia/análise , Glicemia/efeitos dos fármacos , Pão/efeitos adversos , Estudos Cross-Over , Índice Glicêmico/efeitos dos fármacos , Insulina , Morus/química , Extratos Vegetais/farmacologia , Período Pós-Prandial , Triticum , Método Duplo-Cego , Humanos
17.
J Phys Chem Lett ; 13(2): 486-491, 2022 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-35001618

RESUMO

The surface acidity and local coordination environment of zeolites and amorphous silica-aluminas (ASAs) can promote acid-catalyzed C-H activation in many important hydrocarbon conversion reactions. Acid sites generated by penta-coordinated Al species (AlV) can lead to enhanced acidity and changes in the surface coordination. We evaluated the potential of flame-derived ASAs with enriched AlV for C-H activation using hydrogen/deuterium (H/D) exchange with benzene-d6. With increasing Al content of ASAs, the exchange rate increased, whereas the activation energy (Ea) slightly decreased due to the enhanced Brønsted acidity. The ASAs exhibited significantly higher exchange rates and lower Ea values than the sol-gel-derived ASAs and zeolite H-ZSM-5. The superior activity is attributed to the fact that more oxygen coordinated with AlV species on flame-made ASAs, which can act as acceptors for D+, enhancing the deuterium displacement. These findings could offer a valuable alternative strategy for tailoring high-performance solid acids to promote hydrocarbon conversion reactions.

18.
Food Chem ; 370: 131044, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-34509940

RESUMO

The shelf life of chestnut rose beverage is largely dependent on packaging method and storage temperature. In this study, we investigated the effects of packaging beverages in bottles made of either polyethylene terephthalate (PET) or PEN (polyethylene naphthalate)/PET and storage temperature (4, 25, 37, and 55 ℃) on the shelf life of chestnut rose beverage. The physicochemical parameters and enzyme activity of beverages were evaluated, and we found that at 4 °C, the vitamin C, superoxide dismutase, and total polyphenol contents of beverages stored in PEN/PET bottles increased by 9.95 ± 0.49%, 2.86 ± 0.13%, and 3.23 ± 0.09% respectively, compared to beverages in ordinary PET bottles. In addition, other characteristic indicators including total soluble solids, browning index, and color value were also significantly improved. A shelf-life model was established based on the Arrhenius equation, and it will help distributors and consumers to determine the storage time and optimal shelf life of chestnut rose beverage.


Assuntos
Bebidas , Embalagem de Alimentos , Polietilenotereftalatos , Rosa , Bebidas/análise , Polietilenotereftalatos/análise , Temperatura
19.
PLoS One ; 16(7): e0254820, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34293036

RESUMO

The global population is rapidly increasing, the arable land area is losing in a large scale, and the water supply capacity is limited. Meanwhile, China is in a critical period of the transformation of apple industrial structure, and the improvement of apple production efficiency is an important way to increase farmers' output and income, moderate-scale operation is the inevitable trend in agricultural modernization. However, few studies have explored the production efficiency of the apple industry from the perspective of planting scale. In China, there are seven major apple-producing provinces: Shaanxi, Shandong, Gansu, Henan, Shanxi, Hebei, and Liaoning. Therefore, based on provincial panel data of the seven main apple-producing areas in China, this study used the Malmquist productivity index and data envelopment analysis to measure the efficiency level of the apple industry. At the same time, the threshold regression model was used to analyze the characteristics of the change in apple planting scale and production efficiency. The results showed that apple production efficiency in different regions of China exhibited regional differences and time series fluctuations. Apple planting scale had a "double" threshold effect, and the impact on apple production efficiency showed a "negative effect-positive effect" trend. Therefore, the suggestion is to appropriately adjust the scale of operation, take measures according to local conditions, promote the upgrading of apple production technology, and realize the integration of apple production and sales by using "Internet +."


Assuntos
Produção Agrícola , Malus , Mudança Social , China , Fazendeiros
20.
Front Med (Lausanne) ; 8: 744350, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34796185

RESUMO

Background: Hepatitis B virus (HBV) infection is one of the health problems and has adverse effects on public health. However, the consequences of male HBV carriers for assisted reproductive techniques (ART) remain unclear. Objective: To examine whether men with HBV would impact sperm quality and the intrauterine insemination (IUI)/ in vitro fertilization (IVF)/ intracytoplasmic sperm injection (ICSI) outcomes. Methods: We retrospectively analyzed data from 681 infertile couples for IUI/IVF/ICSI fresh cycle outcomes. Case group was 176 infertile couples with male HBV infection undergoing embryo transfer in our center (99 for IVF and 77 for ICSI) and 51 infertile couples for IUI. Negative control was 454 non-infected infertility couples, matched for female age, BMI and infertility duration (102 for IUI and 198 for IVF and 154 for ICSI). Results: Sperm viability among infertile men with HBV infection was significantly lower than control group (74.1 ± 13.7 vs. 77.0 ± 12.8, P < 0.01). Sperm motility was significantly decreased in HBV positive men in comparison to the control group (32.5 ± 14.6 vs. 35.5 ± 12.9, P < 0.05). In IVF/ICSI cycles, two groups had similar results in two pronuclear (2PN) fertilization rate, implantation rate, clinical pregnant rate and abortion rate (P > 0.05). There was also no difference in the clinical pregnant rate and abortion rate in IUI cycles (P > 0.05). Conclusion: Men with HBV infection will affect their sperm quality, but not affect the outcomes of ART.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA