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1.
Foods ; 13(1)2024 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-38201188

RESUMO

Winter dry tea (WDT) exhibits a more intense and lasting aroma compared to dry tea from other seasons; however, this conclusion is solely based on sensory outcomes and lacks corroborative theoretical evidence. Our study aimed to analyze the aroma compounds in WDT and investigate the causes behind the formation of WDT's aroma by analyzing the volatile organic compounds (VOCs) in WDT, spring dry tea (SDT), winter fresh leaves (WFLs) and spring fresh leaves (SFLs) by gas chromatography-mass spectrometry (GC-MS), complemented by an analysis of gene expression pertinent to WFLs and SFLs by using transcriptomic analysis. The results revealed a significant increase in total VOCs in WDT compared to SDT, with WDT exhibiting distinct woody aromas as indicated by a higher α-muurolene content. In WFL, the contents of aldehydes and ketones were richer than those in SFL. Notably, the study found that UDP-glycosyltransferase genes in WFLs were significantly up-regulated, potentially promoting the synthesis of terpene glycosides. These terpene glycosides can release terpene aroma compounds during processing, contributing significantly to the intense and lasting aroma of WDT. Overall, this research provides valuable insights into the mechanism behind aroma formation in Guangdong oolong tea harvested during winter.

2.
Angew Chem Int Ed Engl ; 62(37): e202308579, 2023 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-37486880

RESUMO

Developing hydrogen-bonded organic frameworks (HOFs) that combine functional sites, size control, and storage capability for targeting gas molecule capture is a novel and challenging venture. However, there is a lack of effective strategies to tune the hydrogen-bonded network to achieve high-performance HOFs. Here, a series of HOFs termed as HOF-ZSTU-M (M=1, 2, and 3) with different pore structures are obtained by introducing structure-directing agents (SDAs) into the hydrogen-bonding network of tetrakis (4-carboxyphenyl) porphyrin (TCPP). These HOFs have distinct space configurations with pore channels ranging from discrete to continuous multi-dimensional. Single-crystal X-ray diffraction (SCXRD) analysis reveals a rare diversity of hydrogen-bonding models dominated by SDAs. HOF-ZSTU-2, which forms a strong layered hydrogen-bonding network with ammonium (NH4 + ) through multiple carboxyl groups, has a suitable 1D "pearl-chain" channel for the selective capture of propylene (C3 H6 ). At 298 K and 1 bar, the C3 H6 storage density of HOF-ZSTU-2 reaches 0.6 kg L-1 , representing one of the best C3 H6 storage materials, while offering a propylene/propane (C3 H6 /C3 H8 ) selectivity of 12.2. Theoretical calculations and in situ SCXRD provide a detailed analysis of the binding strength of C3 H6 at different locations in the pearl-chain channel. Dynamic breakthrough tests confirm that HOF-ZSTU-2 can effectively separate C3 H6 from multi-mixtures.

3.
Dalton Trans ; 52(42): 15462-15466, 2023 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-37477392

RESUMO

As a rich green energy source, natural gas is widely used in many fields such as the chemical industry, automobile energy, and daily life. However, it is very challenging to separate and recover C2H6 and C3H8 from natural gas. Metal-organic frameworks (MOFs) as an emerging type of multi-pore porous materials show huge potential in gas adsorption separation. Herein, we report pillar-layered MOFs, Ni (BDC)(DABCO)0.5 (DMOF-X), modified by halogen atoms (F, Cl, Br), and investigate their CH4/C2H6/C3H8 separation performance. The experimental results show that DMOF-Cl exhibited a extremely high adsorption capacity for C3H8 and C2H6. Under the conditions of 298 K and 100 kPa, the adsorption capacities for C3H8 and C2H6 on DMOF-Cl are as high as 6.23 and 4.94 mmol g-1, which are superior to the values for most of the porous materials that have been reported. In addition, DMOF-Cl also shows high C3H8/CH4 (5: 85, V/V) and C2H6/CH4 (10: 85, V/V) separation selectivities, with values of 130.9 and 12.5, respectively. Finally, DMOF-Cl also demonstrated great potential as an adsorbent for separating C3H8/C2H6/CH4.

4.
Nat Commun ; 13(1): 1286, 2022 03 11.
Artigo em Inglês | MEDLINE | ID: mdl-35277491

RESUMO

Voltage-gated sodium (NaV) channels play fundamental roles in initiating and propagating action potentials. NaV1.3 is involved in numerous physiological processes including neuronal development, hormone secretion and pain perception. Here we report structures of human NaV1.3/ß1/ß2 in complex with clinically-used drug bulleyaconitine A and selective antagonist ICA121431. Bulleyaconitine A is located around domain I-II fenestration, providing the detailed view of the site-2 neurotoxin binding site. It partially blocks ion path and expands the pore-lining helices, elucidating how the bulleyaconitine A reduces peak amplitude but improves channel open probability. In contrast, ICA121431 preferentially binds to activated domain IV voltage-sensor, consequently strengthens the Ile-Phe-Met motif binding to its receptor site, stabilizes the channel in inactivated state, revealing an allosterically inhibitory mechanism of NaV channels. Our results provide structural details of distinct small-molecular modulators binding sites, elucidate molecular mechanisms of their action on NaV channels and pave a way for subtype-selective therapeutic development.


Assuntos
Canal de Sódio Disparado por Voltagem NAV1.7 , Bloqueadores do Canal de Sódio Disparado por Voltagem , Sítios de Ligação , Humanos , Canal de Sódio Disparado por Voltagem NAV1.7/química , Estrutura Secundária de Proteína , Sódio/metabolismo , Bloqueadores do Canal de Sódio Disparado por Voltagem/farmacologia
5.
Neurosci Lett ; 655: 35-40, 2017 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-28663052

RESUMO

Motor imagery is one of the most investigated paradigms in the field of brain-computer interfaces (BCIs). The present study explored the feasibility of applying a common spatial pattern (CSP)-based algorithm for a functional near-infrared spectroscopy (fNIRS)-based motor imagery BCI. Ten participants performed kinesthetic imagery of their left- and right-hand movements while 20-channel fNIRS signals were recorded over the motor cortex. The CSP method was implemented to obtain the spatial filters specific for both imagery tasks. The mean, slope, and variance of the CSP filtered signals were taken as features for BCI classification. Results showed that the CSP-based algorithm outperformed two representative channel-wise methods for classifying the two imagery statuses using either data from all channels or averaged data from imagery responsive channels only (oxygenated hemoglobin: CSP-based: 75.3±13.1%; all-channel: 52.3±5.3%; averaged: 64.8±13.2%; deoxygenated hemoglobin: CSP-based: 72.3±13.0%; all-channel: 48.8±8.2%; averaged: 63.3±13.3%). Furthermore, the effectiveness of the CSP method was also observed for the motor execution data to a lesser extent. A partial correlation analysis revealed significant independent contributions from all three types of features, including the often-ignored variance feature. To our knowledge, this is the first study demonstrating the effectiveness of the CSP method for fNIRS-based motor imagery BCIs.


Assuntos
Interfaces Cérebro-Computador , Imaginação , Cinestesia , Movimento , Adulto , Algoritmos , Humanos , Masculino , Modelos Neurológicos , Córtex Motor/fisiologia , Desempenho Psicomotor , Espectroscopia de Luz Próxima ao Infravermelho , Adulto Jovem
6.
Zhonghua Jie He He Hu Xi Za Zhi ; 25(2): 98-101, 2002 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-11953107

RESUMO

OBJECTIVE: To improve the awareness of immunodeficiency tuberculosis. METHODS: 5 autopsy cases of immunodeficiency tuberculosis from 1972 to 2000 in two hospitals were reviewed. RESULTS: The 5 cases were found to have hypoplasia of or damage in the thymus, among them 3 had massive tuberculous lymphadenitis lesions. Multiorgan lesions were found more in both lungs than in other organs, accompanied by lymphatic spread and blood dissemination. The microscopic feature was atypical tuberculosis with great amounts of Mycobacterium tuberculosis. CONCLUSIONS: Hypoplasia of or damage in the thymus and peripheral lymphoid tissue caused deficiency in the immune response, which resulted in the death of the patients with generalised tuberculosis by blood dissemination and lymphatic spread. The underlying mechanism of immunodeficiency tuberculosis is largely unknown, and further research is needed.


Assuntos
Síndromes de Imunodeficiência/complicações , Tuberculose/patologia , Adolescente , Adulto , Criança , Feminino , Humanos , Lactente , Masculino , Tuberculose/imunologia
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