Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 10 de 10
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Food Res Int ; 137: 109388, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33233090

RESUMO

Differences in key odor-active volatile compounds among the head, heart, and tail fractions of freshly distilled spirits from Spine grape (Vitis davidii Foex) wine were identified for the first time by gas chromatography-olfactometry and gas chromatography-mass spectrometry. Results from aroma extract dilution analysis (AEDA) showed that there were 34, 45, and 37 odor-active compounds in the head, heart and tail fractions, respectively. Besides, 20, 22, and 17 quantified compounds, respectively, showed odor activity values (OAVs) > 1. The head fraction was characterized by fruity, fusel/solvent notes owing to higher concentrations of higher alcohols and esters, while the tail fraction had more intense smoky/animal, sweaty/fatty attributes due to higher concentrations of volatile phenols and fatty acids. Finally, the heart fraction was characterized by ethyl octanoate, ethyl hexanoate, ethyl 3-phenylpropanoate, ethyl cinnamate, isoamyl alcohol, guaiacol, 4-ethylguaiacol, 4-vinylguaiacol, 2,3-butanedione, and (E)-ß-damascenone. Furthermore, observation of the distillation progress indicated that different volatiles with various boiling points and solubilities followed diverse distillation patterns: concentrations of most esters, higher alcohols, terpenes and C13-norisoprenoids decreased, while concentrations of volatile phenols, fatty acids and some aromatic compounds increased during distillation. As a result, their final concentrations in the three distillate fractions varied significantly.

2.
Food Res Int ; 137: 109688, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33233263

RESUMO

In this study, fruit-zone microclimate was modified by three treatments, including inter-row mulch (M), the combination of leaf removal applied at the onset of veraison and inter-row mulch (MLR-BV), and the combination of leaf removal applied at complete veraison and inter-row mulch (MLR-EV), in a semi-arid climate in three consecutive years (2015-2017). M decreased fruit-zone reflected solar radiation from vineyard floor and low temperature (10-20 °C) duration, whereas it increased soil temperature and high temperature (> 30 °C) duration. MLR-BV and MLR-EV increased fruit-zone incident photosynthetically active radiation while decreased the duration of 20-25 °C compared to M. Notably, M significantly decreased grape total norisoprenoid concentrations in 2015-2017, and total terpenoid concentrations in 2015-2016. Applying leaf removal applied at the onset of veraison could compensate the decreases of total norisoprenoids and terpenoids caused by M when two treatments were applied together. Besides, M significantly increased grape total C6/C9 compound concentrations, besides, (Z)-3-hexen-1-ol concentrations were significantly higher in grapes of M than those of MLR-BV in 2015-2017. Light exposure and high temperature duration after veraison had strong positive correlations with total norisoprenoids and terpenoids, besides, low temperature duration was positively correlated with total norisoprenoids. In addition, light exposure after veraison had strong negative correlations with total C6/C9 compounds. With respect to the volatile compounds in wines, M significantly decreased the concentrations of isopentanol and ethyl acetate, and the concentrations of ethyl cinnamate, phenylacetaldehyde, phenylethyl alcohol and 3-methylthio-1-propanol were significantly lower in MLR-BV and MLR-EV than in M. The outcome of this study can assist winegrowers to properly adjust vineyard managements to optimize the concentrations of desired volatile compounds in grapes and wines.

3.
Org Lett ; 22(21): 8424-8429, 2020 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-33044834

RESUMO

We report a facile and economical synthesis of α-fluoroacrylic acids via direct electrochemical defluorinative carboxylation of gem-difluoroalkenes with CO2. By using a platinum plate as the working cathode and a cheap nickel plate as the anode in a user-friendly undivided cell under constant current conditions, the reactions proceed smoothly under room temperature, without the use of expensive transition metal catalysts, ligands, external base or reductant, affording the desired adducts in up to 83% yield and 20:1 Z/E ratio, with good functional group tolerance. A cyclic voltammetry study was conducted and suggested a novel ECEC process.

4.
J Sci Food Agric ; 100(9): 3729-3740, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32266978

RESUMO

BACKGROUND: Gibberellic acid (GA3 ), a plant-growth regulator, is often used to obtain enlarged table grape berries and induce seedlessness in them. However, the effects of GA3 on rachis elongation and bunch compactness have seldom been reported in wine-grape production. We assessed the effects of GA3 spraying on wine-grape inflorescences and bunches and their practical implications for viticulture in the Jiaodong Peninsula, China. RESULTS: Various GA3 concentrations were sprayed on field-grown Vitis vinifera L. 'Cabernet Franc' (CF) and 'Cabernet Sauvignon' (CS) grapevines before anthesis in the Jiaodong Peninsula, China, in 2015 and 2016. Inflorescence length during berry development was measured, and flavonoids and aroma compounds in the fruit were detected by high-performance liquid chromatography - mass spectrometry (HPLC-MS) and gas chromatography - mass spectrometry (GC-MS), respectively. For both cultivars, 50 and 100 mg L-1 GA3 caused significant elongation of the rachis, whereas there was no significant effect on inflorescence growth and berry seed number. Anthocyanin, flavonol, and flavan-3-ol levels in mature berries were not significantly influenced by GA3 spraying, whereas C13 -norisoprenoids were modified. CONCLUSION: The application of 50-100 mg L-1 GA3 prior to grapevine anthesis caused elongation of inflorescences and bunches, and eased cluster compactness in CF and CS, and no negative effects were observed on the yield and seed numbers. The concentration and composition of flavonoids and most aroma compounds were not influenced, except that the norisoprenoids were increased by 50 mg L-1 GA3 applications. © 2020 Society of Chemical Industry.

5.
Chem Commun (Camb) ; 55(95): 14303-14306, 2019 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-31713553

RESUMO

Herein, we report that 1,3-diphenylguanidine (DPG) could be utilized for the carboxylative cyclization of homopropargyl amines with CO2 under ambient temperature and pressure, in combination with AgSbF6, which enabled the synthesis of both chiral and achiral 2-oxazinones efficiently. A mechanistic study revealed that the multi-functionality of DPG is critical to the success of the reaction.

6.
Zookeys ; 874: 149-164, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31565022

RESUMO

Panorpa Linnaeus, 1758 is the largest genus in the scorpionfly family Panorpidae. Herein we describe two new species from eastern China, Panorpa jinhuaensis sp. nov. from Jinhua, Zhejiang Province and Panorpa menqiuleii sp. nov. from Yuexi and Huoshan, Anhui Province. Panorpa wrightae Cheng, 1957 from Mount Mogan, Zhejiang Province is considered to be a junior subjective synonym of Panorpa mokansana Cheng, 1957 from the same locality. Panorpa mokansana Cheng, 1957 is redescribed and illustrated in detail. A key to species of Panorpa from eastern China is also provided.

7.
Food Chem ; 292: 237-246, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31054670

RESUMO

The ripeness of a grape is critical to berry composition and to the resultant wine. For wineries with a single cultivar occupying an extensive area, the total soluble solid of grapes can range from 22°Brix to 28°Brix. Accordingly, the influence of different harvest dates (ripeness) on berry compositions and on the resultant wine profile was investigated for Vitis vinifera L. cv. 'Cabernet Sauvignon.' Berry dehydration was observed as berry weight and juice yields decreased. Berry anthocyanins were concentrated and methylated anthocyanin levels fluctuated with increasing delays in harvesting. Hexanal and 2-hexenal levels in must decreased significantly as berries ripened. In the resultant wines, 2,3-butanediol levels increased. Wines harvested earlier were lighter, presented lower color intensity (CI) values and higher yellow% levels, and exhibited richer aroma profiles (compounds). Through a principal component analysis and discriminant analysis, the compounds characterizing each harvest date were identified.


Assuntos
Vitis/química , Vinho/análise , Aldeídos/análise , Antocianinas/análise , Cromatografia Gasosa , Clima , Frutas/química , Frutas/metabolismo , Análise dos Mínimos Quadrados , Análise de Componente Principal , Fatores de Tempo , Vitis/metabolismo , Compostos Orgânicos Voláteis/análise
8.
Int J Mol Sci ; 20(2)2019 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-30669297

RESUMO

Rootstocks are widely used in viticulture due to their resistance to biotic and abiotic stress. Additionally, rootstocks can affect vine growth and berry quality. This study evaluated the effects of eight rootstocks (101-14, 110R, 5A, 5BB, Ganzin 1, Harmony, Riparia Gloire, and SO4) on the vine growth, berry ripening, and flavonoids and aromatic profiles of Cabernet Sauvignon in two consecutive seasons (2015⁻2016). With few exceptions, minor differences were observed among grafted and own-rooted vines. Own-rooted vines produced the least pruning weight but the highest yield. 101-14, 5BB, and SO4 slightly reduced total soluble solids, but increased acidity, showing tendencies for retarding maturation. Ganzin 1 inhibited the accumulation of flavan-3-ols in berry skins. Furthermore, concentrations and proportions of epicatechin-3-O-galate were decreased by rootstocks, except for 110R. 5A, Harmony, and Riparia Gloire enhanced flavonol concentrations. SO4 slightly decreased most of the individual anthocyanin concentrations. With respect to volatile compounds, 110R, Riparia Gloire, and SO4 induced reductions in concentrations of total esters, whilst 101-14, Ganzin 1, 110R, and 5BB led to increases in the concentrations of C13-norisoprenoids. Therefore, with respect to the negative effects of SO4 on berry ripening and the accumulation of anthocyanin and volatile esters, SO4 is not recommended in practice.


Assuntos
Flavonoides/química , Frutas/química , Compostos Fitoquímicos/química , Vitis/química , Compostos Orgânicos Voláteis/química , Fenômenos Químicos , Frutas/crescimento & desenvolvimento , Estações do Ano , Vitis/crescimento & desenvolvimento , Tempo (Meteorologia)
9.
Zhongguo Shi Yan Xue Ye Xue Za Zhi ; 24(3): 827-32, 2016 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-27342518

RESUMO

OBJECTIVE: To investigate the microRNA (miRNA) expression in plasma of patients with aGVHD and without aGVHD after allo-hematopoietic stem cell transplantation (allo-HSCT). METHODS: The miRNAs (miR-423, mirR199a-3p, miR93*, miR377) expression levels in peripheral blood plasma of 25 patients before and after allo-HSCT were detected by real-time PCR. RESULTS: miR-423, miR199a-3p and miR-93* in aGVHD group were significantly upregulated (P<0.05); miR-377 expression was not significantly different between aGVHD and non-aGVHD (P>0.05). CONCLUSION: The expression of miR-423, miR-199a-3p, miR-93* are upregulated in aGVHD group, which can be used as biomarkes to monitor and to diagnose aGVHD.


Assuntos
Doença Enxerto-Hospedeiro/patologia , Transplante de Células-Tronco Hematopoéticas , MicroRNAs/sangue , Biomarcadores/sangue , Doença Enxerto-Hospedeiro/sangue , Humanos , Reação em Cadeia da Polimerase em Tempo Real , Regulação para Cima
10.
Sci Rep ; 6: 26003, 2016 05 18.
Artigo em Inglês | MEDLINE | ID: mdl-27188577

RESUMO

Physical and chemical insult-induced bone marrow (BM) damage often leads to lethality resulting from the depletion of hematopoietic stem and progenitor cells (HSPCs) and/or a deteriorated BM stroma. Notch signaling plays an important role in hematopoiesis, but whether it is involved in BM damage remains unclear. In this study, we found that conditional disruption of RBP-J, the transcription factor of canonical Notch signaling, increased irradiation sensitivity in mice. Activation of Notch signaling with the endothelial cell (EC)-targeted soluble Dll1 Notch ligand mD1R promoted BM recovery after irradiation. mD1R treatment resulted in a significant increase in myeloid progenitors and monocytes in the BM, spleen and peripheral blood after irradiation. mD1R also enhanced hematopoiesis in mice treated with cyclophosphamide, a chemotherapeutic drug that induces BM suppression. Mechanistically, mD1R increased the proliferation and reduced the apoptosis of myeloid cells in the BM after irradiation. The ß chain cytokine receptor Csf2rb2 was identified as a downstream molecule of Notch signaling in hematopoietic cells. mD1R improved hematopoietic recovery through up-regulation of the hematopoietic expression of Csf2rb2. Our findings reveal the role of Notch signaling in irradiation- and drug-induced BM suppression and establish a new potential therapy of BM- and myelo-suppression induced by radiotherapy and chemotherapy.


Assuntos
Medula Óssea/fisiologia , Predisposição Genética para Doença , Proteína de Ligação a Sequências Sinal de Recombinação J de Imunoglobina/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular/administração & dosagem , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Lesões Experimentais por Radiação/fisiopatologia , Receptores de Interleucina-3/metabolismo , Animais , Células Sanguíneas , Medula Óssea/efeitos da radiação , Proteínas de Ligação ao Cálcio , Proteína de Ligação a Sequências Sinal de Recombinação J de Imunoglobina/deficiência , Masculino , Camundongos Endogâmicos C57BL , Células Progenitoras Mieloides/fisiologia , Regeneração , Transdução de Sinais , Baço/citologia , Regulação para Cima
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA