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1.
Small ; 20(9): e2306716, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37863816

RESUMO

The interaction between catalyst and support plays an important role in electrocatalytic hydrogen evolution (HER), which may explain the improvement in performance by phase transition or structural remodeling. However, the intrinsic behavior of these catalysts (dynamic evolution of the interface under bias, structural/morphological transformation, stability) has not been clearly monitored, while the operando technology does well in capturing the dynamic changes in the reaction process in real time to determine the actual active site. In this paper, nitrogen-doped molybdenum atom-clusters on Ti3 C2 TX (MoACs /N-Ti3 C2 TX ) is used as a model catalyst to reveal the dynamic evolution of MoAcs on Ti3 C2 TX during the HER process. Operando X-ray absorption structure (XAS) theoretical calculation and in situ Raman spectroscopy showed that the Mo cluster structure evolves to a 6-coordinated monatomic Mo structure under working conditions, exposing more active sites and thus improving the catalytic performance. It shows excellent HER performance comparable to that of commercial Pt/C, including an overpotential of 60 mV at 10 mA cm-2 , a small Tafel slope (56 mV dec-1 ), and high activity and durability. This study provides a unique perspective for investigating the evolution of species, interfacial migration mechanisms, and sources of activity-enhancing compounds in the process of electroreduction.

2.
J Digit Imaging ; 35(5): 1101-1110, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35478060

RESUMO

To visualise the tumours inside the body on a screen, a long and thin tube is inserted with a light source and a camera at the tip to obtain video frames inside organs in endoscopy. However, multiple artefacts exist in these video frames that cause difficulty during the diagnosis of cancers. In this research, deep learning was applied to detect eight kinds of artefacts: specularity, bubbles, saturation, contrast, blood, instrument, blur, and imaging artefacts. Based on transfer learning with pre-trained parameters and fine-tuning, two state-of-the-art methods were applied for detection: faster region-based convolutional neural networks (Faster R-CNN) and EfficientDet. Experiments were implemented on the grand challenge dataset, Endoscopy Artefact Detection and Segmentation (EAD2020). To validate our approach in this study, we used phase I of 2,200 frames and phase II of 331 frames in the original training dataset with ground-truth annotations as training and testing dataset, respectively. Among the tested methods, EfficientDet-D2 achieves a score of 0.2008 (mAPd[Formula: see text]0.6+mIoUd[Formula: see text]0.4) on the dataset that is better than three other baselines: Faster-RCNN, YOLOv3, and RetinaNet, and competitive to the best non-baseline result scored 0.25123 on the leaderboard although our testing was on phase II of 331 frames instead of the original 200 testing frames. Without extra improvement techniques beyond basic neural networks such as test-time augmentation, we showed that a simple baseline could achieve state-of-the-art performance in detecting artefacts in endoscopy. In conclusion, we proposed the combination of EfficientDet-D2 with suitable data augmentation and pre-trained parameters during fine-tuning training to detect the artefacts in endoscopy.


Assuntos
Artefatos , Redes Neurais de Computação , Humanos , Endoscopia , Aprendizado de Máquina
3.
Zhongguo Zhong Yao Za Zhi ; 40(1): 53-8, 2015 Jan.
Artigo em Zh | MEDLINE | ID: mdl-25993787

RESUMO

Using MS as basic medium, supplemented with 1.0 mg · L(-1) IBA, the adventitious roots of Tripterygium wilfordii were induced, and the good adventitious root culture system was established by leaves or callus induced by leaves as explants. The adventitious roots were also induced with 2.0-4.0 mg · L(-1) NAA and the good adventitious root culture system established by using suspension cells from callus as materials to induce adventitious root. The content of triptolide of three adventitious roots culture system were exceeded in the natural root bark. The content of triptolide of AR3 adventitious roots was the highest about 5.3 times as that in the natural root bark. By using 5 L stirred fermentor during pilot enlarge cultivation, compared with 250 mL flask cultivation, the adventitious roots increment and secondary metabolites content per liter medium showed no significant difference. The accomplishment of this analysis laid a foundation by tissue culture production of the secondary metabolites of T. wilfordii.


Assuntos
Raízes de Plantas/crescimento & desenvolvimento , Técnicas de Cultura de Tecidos/métodos , Tripterygium/crescimento & desenvolvimento , Meios de Cultura/química , Meios de Cultura/metabolismo , Fermentação , Reguladores de Crescimento de Plantas/análise , Reguladores de Crescimento de Plantas/metabolismo , Raízes de Plantas/metabolismo , Técnicas de Cultura de Tecidos/instrumentação , Tripterygium/metabolismo
4.
Phytochemistry ; 223: 114115, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38710377

RESUMO

A total of twenty-two diterpenoid alkaloids, including ten unprecedented ones, namely refractines C-L, were isolated from the roots of Aconitum refractum (Finet et Gagnep.) Hand.-Mazz. Refractine C was the first example of a natural diterpenoid alkaloid wherein C-19 is linked to N position by an oxaziridine ring. Refractine L was a rare glycosidic diterpenoid alkaloid with fructofuranoside. Most of the isolated compounds obtained from a previous study were screened for their anti-inflammatory and myocardial protective activities. The autophagy-inducing effects of some of these compounds on RAW 264.7 cells were evaluated by assessing the expression of microtubule-associated protein 1 light chain 3 (LC3-II/LC3-I). Results revealed that some compounds exerted varying levels of inhibitory effects on the proliferative activity of RAW 264.7 cells.


Assuntos
Aconitum , Alcaloides , Autofagia , Diterpenos , Aconitum/química , Camundongos , Animais , Autofagia/efeitos dos fármacos , Células RAW 264.7 , Alcaloides/farmacologia , Alcaloides/isolamento & purificação , Alcaloides/química , Diterpenos/farmacologia , Diterpenos/química , Diterpenos/isolamento & purificação , Proliferação de Células/efeitos dos fármacos , Estrutura Molecular , Relação Estrutura-Atividade , Relação Dose-Resposta a Droga , Raízes de Plantas/química
5.
Food Chem ; 453: 139581, 2024 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-38754354

RESUMO

This study investigated the impact of ultrasound treatment on dioscorin, the primary storage protein found in yam tubers. Three key factors, namely ultrasound power, duration, and frequency, were focused on. The research revealed that ultrasound-induced cavitation effects disrupted non-covalent bonds, resulting in a reduction in α-helix and ß-sheet contents, decreased thermal stability, and a decrease in the apparent hydrodynamic diameter (Dh) of dioscorin. Additionally, previously hidden amino acid groups within the molecule became exposed on its surface, resulting in increased surface hydrophobicity (Ho) and zeta-potential. Under specific ultrasound conditions (200 W, 25 kHz, 30 min), Dh decreased while Ho increased, facilitating the adsorption of dioscorin molecules onto the oil-water interface. Molecular dynamics (MD) simulations showed that at lower frequencies and pressures, the structural flexibility of dioscorin's main chain atoms increased, leading to more significant fluctuations between amino acid residues. This transformation improved dioscorin's emulsifying properties and its oil-water interface affinity.


Assuntos
Interações Hidrofóbicas e Hidrofílicas , Simulação de Dinâmica Molecular , Dioscorea/química , Emulsões/química , Proteínas de Plantas/química , Ondas Ultrassônicas
6.
Dalton Trans ; 52(3): 659-667, 2023 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-36537538

RESUMO

Building metal-organic frameworks (MOFs) covalently modified by onium halides is a promising approach to develop efficient MOF-based heterogeneous catalysts for the cycloaddition of CO2 to epoxides (CCE) into cyclic carbonates. Herein, we report a novel zirconium-based MOF covalently modified by methyl pyridinium bromide, Zr6O4(OH)4(MPTDC)2.2(N-CH3-MPTDC)3.8Br3.8 ((Br-)CH3-Pyridinium-MOF-1), where MPTDC denotes 3-methyl-4-pyridin-4-yl-thieno[2,3-b] thiophene-2,5-dicarboxylate. The structure and composition of this complex were fully characterized with PXRD, NMR, XPS, TEM and so on. CO2 adsorption experiments show that (Br-)CH3-Pyridinium-MOF-1 has a higher affinity for CO2 than its electrically neutral precursor, which should be attributed to the fact that charging frameworks containing pyridinium salt have stronger polarization to CO2. (Br-)CH3-Pyridinium-MOF-1 integrated reactive Lewis acid sites and Br- nucleophilic anions and exhibited efficient catalytic activity for CCE under ambient pressure in the absence of co-catalysts and solvents. Furthermore, (Br-)CH3-Pyridinium-MOF-1 was recycled after five successive cycles without substantial loss in catalytic activity. The corresponding reaction mechanism also was speculated.

8.
Sci Rep ; 12(1): 5168, 2022 03 25.
Artigo em Inglês | MEDLINE | ID: mdl-35338223

RESUMO

Shennongjia is one of the most important ecological function areas and ecologically vulnerable zones in the world. With the rapid development of social economies, especially tourism, the ecological environment of Shennongjia has experienced profound changes. Exploring the characteristics and changing trends of ecological environment in Shennongjia will help to analyze the causes of the damage to the ecological environment, and build a vulnerability analysis framework with multi-scale, multi-element, multi-flow, and multi-circulation characteristics, which provides an effective research paradigm and analysis tool for the study of regional ecological vulnerability. With the support of RS and GIS technology, this study uses spatial principal component analysis (SPCA) and the vulnerability scoring diagram (VSD) model to comprehensively and quantitatively analyze the spatial and temporal evolution characteristics and driving forces of ecological vulnerability in Shennongjia from 1996 to 2018. The VSD model was selected to decompose the vulnerability into three components of "exposure-sensitivity-adaptation", and 16 indicators were selected to construct an ecological vulnerability evaluation system in Shennongjia, and the evaluation data were organized in a progressive and detailed way. (1) During the study period, the overall ecological vulnerability of Shennongjia is in a mild vulnerability level, exhibiting differentiation characteristics of high in the northeast and low in the southwest. High vulnerability zones are mainly distributed in the main towns and roads. (2) The risk of ecological vulnerability of the entire region presents the characteristics of continuous decline. (3) Land-use types, population density, and vegetation coverage are the main factors driving the evolution of ecological vulnerability. (4) A high level of coupling coordination exists between ecological vulnerability and landscape patterns. Analyses of the ecological vulnerability of Shennongjia shows that the entire region is in a mild vulnerability level. The extreme vulnerability risk of the ecological environment shows polarization. The evolution of ecological environment in Shennongjia is the result of the interaction between human activities and natural environment. This study offers an effective way to assess ecological vulnerability and provides some strategies and guidance for improving ecological security.


Assuntos
Ecossistema , China , Cidades , Humanos , Análise de Componente Principal
9.
Front Pharmacol ; 13: 851680, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35496303

RESUMO

Background: Fuzheng Kang'ai decoction (FZKA) has been widely used to treat Non-Small Cell Lung Cancer (NSCLC) patients in China for decades, showing definitively curative effects in clinic. Recently, we found that FZKA could induce NSCLC cell ferroptosis, another type of programmed cell death (PCD), which is totally different from cell apoptosis. Therefore, in the present study, we aim to discover the exact mechanism by which FZKA induces NSCLC cell ferroptosis, which is rarely studied in Traditional Chinese Medicine (TCM). Methods: Cell proliferation assay were performed to detect the cell viability. Cell ferroptosis triggered by FZKA was observed by performing lipid peroxidation assay, Fe2+ Ions assay, and mitochondrial ultrastructure by transmission electron microscopy. Ferroptosis inhibitors including liproxstatin-1 and UAMC 3203 were used to block ferroptosis. The ratio of GSH/GSSG was done to measure the alteration of oxidative stress. Western blot and qRT-PCR were carried out to detect the expression of solute carrier family 7 member 11 (SLC7A11), solute carrier family 3 member 2 (SLC3A2) and glutathione peroxidase 4 (GPX4) at protein and mRNA levels, respectively. Lentivirus transfection was performed to overexpress GPX4 stably. Animal model was done to verify the effect of FZKA-induced ferroptosis in NSCLC in vivo and immunohistochemistry was done to detect the expression of SLC7A11, SLC3A2 and GPX4 at protein level. Results: First of all, in vitro experiments confirmed the inhibition effect of FZKA on NSCLC cell growth. We then, for the first time, found that FZKA induced NSCLC cell ferroptosis by increasing lipid peroxidation and cellular Fe2+ Ions. Moreover, characteristic morphological changes of NSCLC cell ferroptosis was observed under transmission electron microscopy. Mechanistically, GPX4, as a key inhibitor of lipid peroxidation, was greatly suppressed by FZKA treatment both at protein and mRNA levels. Furthermore, system xc- (SLC7A11 and SLC3A2) were found to be suppressed and a decreased GSH/GSSG ratio was observed at the same time when treated with FZKA. Notably, overexpressing GPX4 reversed the effect of FZKA-induced NSCLC cell ferroptosis significantly. Finally, the above effect was validated using animal model in vivo. Conclusion: Our findings conclude that GPX4 plays a crucial role in FZKA-induced NSCLC cell ferroptosis, providing a novel molecular mechanism by which FZKA treats NSCLC.

10.
Front Neurosci ; 15: 648724, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34366768

RESUMO

Melodic intonation therapy (MIT) positively impacts the speech function of patients suffering from aphasia and strokes. Fixed-pitch melodies and phrases formulated in MIT provide the key to the target language to open the language pathway. This randomized controlled trial compared the effects of music therapy-based MIT and speech therapy on patients with non-fluent aphasia. The former is more effective in the recovery of language function in patients with aphasia. Forty-two participants were enrolled in the study, and 40 patients were registered. The participants were randomly assigned to two groups: the intervention group (n = 20; 16 males, 4 females; 52.90 ± 9.08 years), which received MIT, and the control group (n = 20; 15 males, 5 females; 54.05 ± 10.81 years), which received speech therapy. The intervention group received MIT treatment for 30 min/day, five times a week for 8 weeks, and the control group received identical sessions of speech therapy for 30 min/day, five times a week for 8 weeks. Each participant of the group was assessed by a Boston Diagnostic Aphasia Examination (BDAE) at the baseline (t1, before the start of the experiment), and after 8 weeks (t2, the experiment was finished). The Hamilton Anxiety Scale (HAMA) and Hamilton Depression Scale (HAMD) were also measured on the time points. The best medical care of the two groups is the same. Two-way ANOVA analysis of variance was used only for data detection. In the spontaneous speech (information), the listening comprehension (right or wrong, word recognition, and sequential order) and repetitions of the intervention group were significantly higher than the control group in terms of the cumulative effect of time and the difference between groups after 8 weeks. The intervention group has a significant time effect in fluency, but the results after 8 weeks were not significantly different from those in the control group. In terms of naming, the intervention group was much better than the control group in spontaneous naming. Regarding object naming, reaction naming, and sentence completing, the intervention group showed a strong time accumulation effect. Still, the results after 8 weeks were not significantly different from those in the control group. These results indicate that, compared with speech therapy, MIT based on music therapy is a more effective musical activity and is effective and valuable for the recovery of speech function in patients with non-fluent aphasia. As a more professional non-traumatic treatment method, MIT conducted by qualified music therapists requires deeper cooperation between doctors and music therapists to improve rehabilitating patients with aphasia. The Ethics Committee of the China Rehabilitation Research Center approved this study (Approval No. 2020-013-1 on April 1, 2020) and was registered with the Chinese Clinical Trial Registry (Registration number: Clinical Trials ChiCTR2000037871) on September 3, 2020.

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