Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 7 de 7
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Inorg Chem ; 62(29): 11611-11617, 2023 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-37428154

RESUMO

The development of hierarchically porous metal-organic frameworks (MOFs) with high stability is desirable to expand their applications but remains challenging. Herein, an anionic sodalite-type microporous MOF (Yb-TTCA; TTCA3- = triphenylene-2,6,10-tricarboxylate) was synthesized, which shows outstanding catalytic activities for the cycloaddition of CO2 into cyclic carbonates. Moreover, the microporous Yb-TTCA can be transformed into a hierarchical micro- and mesoporous Yb-TTCA by water treatment with the mesopore sizes of 2 to 12 nm. The hierarchically porous Yb-TTCA (HP-Yb-TTCA) not only exhibits a high thermal stability up to 500 °C but also shows a high chemical stability in aqueous solutions with pH values ranging from 2 to 12. In addition, the HP-Yb-TTCA displays enhanced performance for the removal of organic dyes in comparison with microporous Yb-TTCA. This work provides a facile way to construct hierarchically porous MOF materials.

2.
Inorg Chem ; 61(46): 18545-18553, 2022 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-36346744

RESUMO

A new Dy-based complex, [Dy2(phen)4(PAA)4](ClO4)2 (1), was obtained by using 4-hydroxyphenyl acetate (HPAA) as a ligand and 1,10-phenanthroline as an auxiliary ligand. Complex 1 shows a dinuclear structure and a 2D supramolecular layer constructed by π-π stacking interactions. The complex displays a characteristic Dy(III) emission. Moreover, magnetic susceptibility measurements revealed that 1 exhibits a single-molecule magnet (SMM) behavior. In addition, it also shows a proton conductivity of 1.08 × 10-5 S cm-1 under 353 K and 100% relative humidity conditions, which is mainly assigned to H-bonded networks formed by the undeprotonated and uncoordinated phenolic groups of HPAA ligands and guest water molecules. Remarkably, 1 is the first example of a dinuclear complex showing photoluminescence, SMM behavior, and proton conduction.

3.
J Comput Sci Technol ; 37(5): 1026-1048, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36281257

RESUMO

With the advancing of location-detection technologies and the increasing popularity of mobile phones and other location-aware devices, trajectory data is continuously growing. While large-scale trajectories provide opportunities for various applications, the locations in trajectories pose a threat to individual privacy. Recently, there has been an interesting debate on the reidentifiability of individuals in the Science magazine. The main finding of Sánchez et al. is exactly opposite to that of De Montjoye et al., which raises the first question: "what is the true situation of the privacy preservation for trajectories in terms of reidentification?" Furthermore, it is known that anonymization typically causes a decline of data utility, and anonymization mechanisms need to consider the trade-off between privacy and utility. This raises the second question: "what is the true situation of the utility of anonymized trajectories?" To answer these two questions, we conduct a systematic experimental study, using three real-life trajectory datasets, five existing anonymization mechanisms (i.e., identifier anonymization, grid-based anonymization, dummy trajectories, k-anonymity and ε-differential privacy), and two practical applications (i.e., travel time estimation and window range queries). Our findings reveal the true situation of the privacy preservation for trajectories in terms of reidentification and the true situation of the utility of anonymized trajectories, and essentially close the debate between De Montjoye et al. and Sánchez et al. To the best of our knowledge, this study is among the first systematic evaluation and analysis of anonymized trajectories on the individual privacy in terms of unicity and on the utility in terms of practical applications. Supplementary Information: The online version contains supplementary material available at 10.1007/s11390-022-2409-x.

4.
Inorg Chem ; 60(19): 14924-14931, 2021 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-34529419

RESUMO

The exploitation of highly stable and active catalysts for the conversion of CO2 into valuable fuels is desirable but is a great challenge. Herein, we report that the incorporation of chromophores into metal-organic frameworks (MOFs) could afford robust catalysts for efficient CO2 conversion. Specifically, a porous Nd(III) MOF (Nd-TTCA; TTCA3- = triphenylene-2,6,10-tricarboxylate) was constructed by incorporating one-dimensional Nd(CO2)n chains and TTCA3- ligands, which exhibits a very high stability, retaining its framework not only in the air at 300 °C for 2 h but also in boiling aqueous solutions at pH 1-12 for 7 days. More importantly, Nd-TTCA has achieved a 5-fold improvement in photocatalytic activity for reducing CO2 to HCOOH and a 10-fold improvement in catalytic activity for the cycloaddition of CO2 into cyclic carbonate in comparison to those of H3TTCA itself. This work gives a new strategy to design efficient artificial crystalline catalysts for CO2 conversion.

5.
Ergonomics ; 61(2): 273-283, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28682154

RESUMO

Visual lobe is a useful tool for predicting visual search performance. Up till now, no study has focused on dynamic visual lobe. This study developed a dynamic visual lobe measurement system (DVLMS) that could effectively map dynamic visual lobe and calculate visual lobe shape indices. The effects of display movement velocity on lobe shape indices were examined under four velocity conditions: 0, 4, 8 and 16 deg/s. In general, with the increase of display movement velocity, visual lobe area and perimeter became smaller, whereas lobe shape roundness, boundary smoothness, symmetry and regularity deteriorated. The elongation index was not affected by velocity. Regression analyses indicated that display movement velocity was important in determining dynamic visual lobe shape indices. Dynamic visual lobe provides another option for better understanding dynamic vision, in addition to dynamic visual acuity. Findings of this study can provide guidelines for analysing and designing dynamic visual tasks. Practitioner Summary: Dynamic visual lobe is important in reflecting the visual ability of searching for a moving target. We developed a dynamic visual lobe measurement system (DVLMS) and examined display movement velocity's effects on lobe shape. Findings revealed that velocity was a key factor affecting dynamic visual lobe shape indices.


Assuntos
Reconhecimento Visual de Modelos , Estimulação Luminosa/métodos , Campos Visuais , Percepção Visual , Humanos , Reprodutibilidade dos Testes , Análise e Desempenho de Tarefas , Adulto Jovem
6.
PLoS One ; 11(2): e0149031, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26862759

RESUMO

It is well known that natriuretic peptides (NPs) are involved in the regulation of gastrointestinal motility. Interstitial cells of Cajal (ICC) are the pacemaker cells of gastrointestinal motility and gastrointestinal dyskinesia is one of the important digestive tract symptoms of depression. However, it is unclear whether they are involved in depression-induced loss of ICC. The aim of the present study was to investigate the relationship between the natriuretic peptide signaling pathway and depression-induced loss of gastric ICC in depressed rats. These results showed that the expression of c-kit and stem cell factor (SCF) in smooth muscle layers of stomach were down-regulated in depressed rats at the mRNA and protein levels. The expression of natriuretic peptide receptor (NPR)-A, B and C were up-regulated in the stomach of depressed rats at the mRNA and protein levels. NPR-A, B and C can significantly decrease the expression of SCF to treat cultured gastric smooth muscle cells (GSMCs) obtained from normal rats with different concentrations of C-type natriuretic peptide (CNP). Pretreatment of cultured GSMCs with 8-Brom-cGMP (8-Br-cGMP, a membrane permeable cGMP analog), cANF (a specific NPR-C agonist) and CNP (10-6 mol/L) demonstrated that 8-Br-cGMP had a similar effect as CNP, but treatment with cANF did not. The results of the methyl thiazolyl tetrazolium bromide (MTT) assay indicated that high concentrations of cANF (10-6 mol/L) restrained the proliferation of cultured GSMCs. Taken together, these results indicate that the up-regulation of the NPs/NPR-C and NPs/NPR-A, B/cGMP signaling pathways may be involved in depression-induced loss of gastric ICC.


Assuntos
Depressão/metabolismo , Mucosa Gástrica/metabolismo , Células Intersticiais de Cajal/metabolismo , Proteínas Proto-Oncogênicas c-kit/metabolismo , Transdução de Sinais , Fator de Células-Tronco/metabolismo , Animais , Peso Corporal , Proliferação de Células , Depressão/fisiopatologia , Regulação para Baixo , Regulação da Expressão Gênica , Masculino , Miócitos de Músculo Liso/citologia , Peptídeos Natriuréticos/metabolismo , Proteínas Proto-Oncogênicas c-kit/biossíntese , Ratos , Ratos Sprague-Dawley , Receptores do Fator Natriurético Atrial/biossíntese , Receptores do Fator Natriurético Atrial/metabolismo , Fator de Células-Tronco/biossíntese , Sais de Tetrazólio/química , Tiazóis/química , Regulação para Cima
7.
World J Gastroenterol ; 21(5): 1518-30, 2015 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-25663771

RESUMO

AIM: To investigate the distribution and expression of C-type natriuretic peptide (CNP)/natriuretic peptide receptor B (NPR-B) in the rectum of a rodent depression model and the interventional effect of Xiaoyaosan (XYS). METHODS: Male rats (n = 45) of clean grade (200 ± 20 g) were divided into five groups after one week of adaptive feeding: primary control, depression model, low dose XYS, middle dose XYS, and high dose XYS. The animal experiment continued for 3 wk. Primary controls were fed normally ad libitum. The rats of all other groups were raised in solitary and exposed to classic chronic mild unpredictable stimulation each day. XYS groups were perfused intragastrically with low dose, middle dose, and high dose XYS one hour before stimulation. Primary control and depression model groups were perfused intragastrically with normal saline under similar conditions as the XYS groups. Three weeks later, all rats were sacrificed, and the expression levels of CNP and NPR-B in rectum tissues were analyzed by immunohistochemistry, real-time polymerase chain reaction, and Western blotting. RESULTS: CNP and NPR-B were both expressed in the rectum tissues of all rats. However, the expression levels of CNP and NPR-B at both gene and protein levels in the depression model group were significantly higher when compared to the primary control group (n = 9; P < 0.01). XYS intervention markedly inhibited the expression levels of CNP and NPR-B in depressed rats. The expression levels of CNP and NPR-B in the high dose XYS group did not significantly differ from the expression levels in the primary control group. Additionally, the high and middle dose XYS groups (but not the low dose group) significantly exhibited lower CNP and NPR-B expression levels in the rectum tissues of the respectively treated rats compared to the untreated depression model cohort (n = 9; P < 0.01). CONCLUSION: The CNP/NPR-B pathway is upregulated in the rectum of depressed rats and may be one mechanism for depression-associated digestive disorders. XYS antagonizes this pathway at least partially.


Assuntos
Antidepressivos/farmacologia , Depressão/tratamento farmacológico , Medicamentos de Ervas Chinesas/farmacologia , Peptídeo Natriurético Tipo C/metabolismo , Reto/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Animais , Comportamento Animal/efeitos dos fármacos , Depressão/genética , Depressão/metabolismo , Depressão/psicologia , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Masculino , Peptídeo Natriurético Tipo C/genética , RNA Mensageiro/metabolismo , Ratos Sprague-Dawley , Receptores do Fator Natriurético Atrial/efeitos dos fármacos , Receptores do Fator Natriurético Atrial/genética , Receptores do Fator Natriurético Atrial/metabolismo , Reto/metabolismo , Fatores de Tempo , Regulação para Cima
SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa