Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 97
Filtrar
1.
Hum Genomics ; 18(1): 114, 2024 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-39390620

RESUMO

BACKGROUND: Whole genome sequencing (WGS) is becoming increasingly prevalent for molecular diagnosis, staging and prognosis because of its declining costs and the ability to detect nearly all genes associated with a patient's disease. The currently widely accepted variant calling pipeline, GATK, is limited in terms of its computational speed and efficiency, which cannot meet the growing analysis needs. RESULTS: Here, we propose a fast and accurate DNASeq variant calling workflow that is purely composed of tools from LUSH toolkit. The precision and recall measurements indicate that both the LUSH and GATK pipelines exhibit high levels of consistency, with precision and recall rates exceeding 99% on the 30x NA12878 dataset. In terms of processing speed, the LUSH pipeline outperforms the GATK pipeline, completing 30x WGS data analysis in just 1.6 h, which is approximately 17 times faster than GATK. Notably, the LUSH_HC tool completes the processing from BAM to VCF in just 12 min, which is around 76 times faster than GATK. CONCLUSION: These findings suggest that the LUSH pipeline is a highly promising alternative to the GATK pipeline for WGS data analysis, with the potential to significantly improve bedside analysis of acutely ill patients, large-scale cohort data analysis, and high-throughput variant calling in crop breeding programs. Furthermore, the LUSH pipeline is highly scalable and easily deployable, allowing it to be readily applied to various scenarios such as clinical diagnosis and genomic research.


Assuntos
Software , Sequenciamento Completo do Genoma , Fluxo de Trabalho , Humanos , Sequenciamento Completo do Genoma/métodos , Genoma Humano/genética , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Polimorfismo de Nucleotídeo Único/genética , Biologia Computacional/métodos
2.
J Am Chem Soc ; 146(43): 29315-29324, 2024 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-39433374

RESUMO

In traditional hydrogenation, where H2 and substrates with unsaturated bonds are activated on the same catalyst (contact mode), competitive hydrogenation of multiple reducible groups often occurs. We employ an unbiased H-cell for selective hydrogenation of the nitro group when multiple reducible groups are present. The setup spatially separates H2 and nitroarenes into two chambers connected by a proton-exchange membrane, thus adding barriers for a Langmuir-Hinshelwood-type mechanism that is common in thermocatalytic hydrogenation. Through a unique proton/electron transfer pathway that is specific to nitro functional group reduction to hydroxylamine, side reactions like C═C, C═O, and C≡C bond hydrogenation are fully avoided. Using Pd/C for H2 activation, and CNT for selective proton/electron transfer to -NO2 groups while being inert to C≡C, C═C, and C═O hydrogenation, the system effectively eliminates the competitive hydrogenation, achieving 100% nitro-group reduction selectivity in the hydrogenation of various nitroarenes, in sharp contrast to negligible selectivity over the same catalysts in a batch reactor under contact mode. This device enables selectivity control in hydrogenation reactions, moving beyond the traditional focus on catalyst active site engineering.

3.
Bioorg Chem ; 148: 107455, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38772289

RESUMO

Poly(ADP-ribose) polymerase-1 (PARP-1) is a crucial member of DNA repair enzymes responsible for repairing DNA single-strand breaks. Developing PARP inhibitors based on synthetic lethality strategies is an effective approach for treating breast cancer and other diseases. In this study, a series of novel piperidine-based benzamide derivatives were designed and synthesized using structure-based drug design principles. The anticancer activities of these compounds were evaluated against five human cancer cell lines (MDA-MB-436, CAPAN-1, SW-620, HepG2, SKOV3, and PC3) and the preliminary structure-activity relationships were delineated. Among the compounds, 6a and 15d demonstrated potent antiproliferative effects against MDA-MB-436 cells with IC50 values of 8.56 ± 1.07 µM and 6.99 ± 2.62 µM, respectively. Furthermore, both compounds exhibited excellent inhibitory activity against PARP-1, with IC50 values of 8.33 nM and 12.02 nM, respectively. Mechanistic investigations revealed that 6a and 15d effectively inhibited colony formation and cell migration of HCT116 cells. Moreover, they induced apoptosis by upregulating the expression of Bax and cleaved Caspase-3, while downregulating the expression of Caspase-3 and Bcl-2 in HCT116 cells. Based on its impressive pharmacodynamic data in vitro, we conducted a study to evaluate the efficacy of 15d in a xenograft tumor model in mice when used in combination with cytotoxic agents. Collectively, these findings suggest that 15d could be promising drug candidates worthy of further investigation.


Assuntos
Antineoplásicos , Apoptose , Proliferação de Células , Relação Dose-Resposta a Droga , Desenho de Fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Piperidinas , Poli(ADP-Ribose) Polimerase-1 , Inibidores de Poli(ADP-Ribose) Polimerases , Humanos , Piperidinas/farmacologia , Piperidinas/química , Piperidinas/síntese química , Relação Estrutura-Atividade , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Inibidores de Poli(ADP-Ribose) Polimerases/síntese química , Inibidores de Poli(ADP-Ribose) Polimerases/química , Antineoplásicos/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Proliferação de Células/efeitos dos fármacos , Animais , Poli(ADP-Ribose) Polimerase-1/antagonistas & inibidores , Poli(ADP-Ribose) Polimerase-1/metabolismo , Estrutura Molecular , Camundongos , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Camundongos Nus , Camundongos Endogâmicos BALB C
4.
BMC Public Health ; 24(1): 2778, 2024 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-39394095

RESUMO

BACKGROUND: The impact of polycyclic aromatic hydrocarbons (PAHs) on lung function has garnered attention, but studies mostly focus on individual effect. This study investigates urinary PAH metabolites as biomarkers of exposure and assesses the relationships between single and combined exposures to nine urinary PAH metabolites and lung function in adults. METHODS: Data from 4040 adults in the 2007-2012 National Health and Nutrition Examination Survey (NHANES) were analyzed. Weighted generalized linear models estimated the effects of individual PAH metabolites on lung function. Additionally, weighted quantile sum (WQS) regression, quantile g-computation (qgcomp), and Bayesian kernel machine regression (BKMR) were employed to evaluate the combined impacts of multiple PAH metabolites. RESULTS: Analyses of individual PAH metabolites revealed negative associations with lung function, excluding forced vital capacity (FVC). The WQS, qgcomp, and BKMR models consistently showed that exposure to multiple PAH metabolites was associated with lung function decrease. WQS indicated that 2-hydroxynaphthalene (2-NAP) was the largest contributor to the reductions in forced expiratory volume in 1 s (FEV1), FVC, peak expiratory flow (PEF), and forced expiratory flow from 25 to 75% of FVC (PEF25-75%). Additionally, 1-hydroxypyrene (1-PYR) was the primary PAH metabolite contributing to the decreases in FEV1/FVC and fractional exhaled nitric oxide (FeNO). The combined effect of urinary PAH metabolites did not affect FVC in the current smokers or FeNO in nonsmokers, but decreased FEV1/FVC in current smokers. CONCLUSION: This study strengthens the negative relationships between multiple PAH metabolites exposure and lung function in adults. Given the limitations of this study, including the lack of knowledge of other exposure pathways and the uncertainty of urinary metabolites, further research is necessary to explore the mechanisms underlying these associations and to address the limitations in exposure assessment.


Assuntos
Pulmão , Inquéritos Nutricionais , Hidrocarbonetos Policíclicos Aromáticos , Humanos , Hidrocarbonetos Policíclicos Aromáticos/urina , Masculino , Adulto , Feminino , Estados Unidos , Pessoa de Meia-Idade , Testes de Função Respiratória , Biomarcadores/urina , Exposição Ambiental/efeitos adversos , Exposição Ambiental/análise
5.
Environ Monit Assess ; 196(2): 158, 2024 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-38231357

RESUMO

The construction of low-carbon cities is an optimal means to balance the competing interests of economic growth and carbon emission reduction. This study focuses on the optimization of land use patterns with a low carbon orientation, taking the Chengdu-Chongqing Economic Circle (CCEC), the fourth-largest economic growth pole in China, as an example. The panel data regression analysis is carried out to identify the dynamic correlations between the landscape changes and the carbon emission induced by land use and land cover change (LICE) of each city, each year, for the last 20 years. The results show that the CCEC has witnessed a 142.85% increase in carbon emissions during the period studied, with the growth of built-up land contributing 94% of total carbon emissions from 2000 to 2020. By constructing the panel regression model, this study finds that the intensity of carbon emissions increases significantly as the urban built-up land area and the agglomeration of artificial structures increase. The conversion of cropland, which dominates the landscape pattern, to built-up land has led to further fragmentation of the landscape pattern and a reduction in LPI, thus increasing carbon emissions. And a more complex regional landscape pattern will have a positive impact on carbon emission reduction. Based on the above findings, suggestions are articulated for carbon emission reduction.


Assuntos
Desenvolvimento Econômico , Monitoramento Ambiental , China , Carbono , Cidades
6.
Cell Biol Int ; 47(3): 622-633, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36448366

RESUMO

Hepatocyte growth factor receptor (HGFR or Met) upregulation has been proven to play important roles in non-small cell lung carcinoma (NSCLC). Interestingly, chemoresistance against epidermal growth factor receptor (EGFR) inhibitors including erlotinib and gefitinib was also related to Met. Targeting bromodomain and extra terminal domain (BET) proteins, especially BRD4, has shown inhibitory effects on lung cancer, but the mechanism is unclear. Herein, we found that JQ1 (BET inhibitor) suppressed NSCLC cell growth, reduced the Met expression, and contributed to inactivation of PI3K/Akt and MAPK/ERK pathways. Moreover, another BET protein inhibitor I-BET151, or BRD4 depletion, also inhibited NSCLC cell growth and downregulated Met. JQ1 inhibited HGF-induced cell growth and Met/PI3K/Akt activation, also inhibited A549 tumor growth in xenograft mouse models, in parallel with Met downregulation. Moreover, JQ1 inhibited the growth of paired erlotinib-sensitive and resistant HCC827 cells in parallel with Met downregulation and PI3K/Akt signaling inactivation. JQ1 also exerted inhibitory influences on the growth of erlotinib-sensitive and resistant HCC827 tumors in xenograft mouse models. These results suggested that targeting BET proteins inhibited NSCLC via downregulating Met and inactivating PI3K/AKT pathway. Our findings reveal a novel mechanism of BET proteins implicated in NSCLC progression with Met taken into consideration.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Humanos , Animais , Camundongos , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Cloridrato de Erlotinib/farmacologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Nucleares/metabolismo , Regulação para Baixo , Fosfatidilinositol 3-Quinases/metabolismo , Linhagem Celular Tumoral , Fatores de Transcrição/metabolismo , Neoplasias Pulmonares/patologia , Proliferação de Células , Resistencia a Medicamentos Antineoplásicos , Ensaios Antitumorais Modelo de Xenoenxerto , Inibidores de Proteínas Quinases/farmacologia , Proteínas de Ciclo Celular/metabolismo
7.
Entropy (Basel) ; 25(8)2023 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-37628158

RESUMO

Feature selection is a crucial process in machine learning and data mining that identifies the most pertinent and valuable features in a dataset. It enhances the efficacy and precision of predictive models by efficiently reducing the number of features. This reduction improves classification accuracy, lessens the computational burden, and enhances overall performance. This study proposes the improved binary golden jackal optimization (IBGJO) algorithm, an extension of the conventional golden jackal optimization (GJO) algorithm. IBGJO serves as a search strategy for wrapper-based feature selection. It comprises three key factors: a population initialization process with a chaotic tent map (CTM) mechanism that enhances exploitation abilities and guarantees population diversity, an adaptive position update mechanism using cosine similarity to prevent premature convergence, and a binary mechanism well-suited for binary feature selection problems. We evaluated IBGJO on 28 classical datasets from the UC Irvine Machine Learning Repository. The results show that the CTM mechanism and the position update strategy based on cosine similarity proposed in IBGJO can significantly improve the Rate of convergence of the conventional GJO algorithm, and the accuracy is also significantly better than other algorithms. Additionally, we evaluate the effectiveness and performance of the enhanced factors. Our empirical results show that the proposed CTM mechanism and the position update strategy based on cosine similarity can help the conventional GJO algorithm converge faster.

8.
Small ; 18(49): e2204996, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36287092

RESUMO

DNA nanotubes with prescribed geometry could allow for nanomaterial organization with designed optical or electrical function. As one of the dominating driving forces for DNA nanotube assembly, intrinsic curvature and twist of building blocks can be induced by bending deformation and twisting deformation. However, it is still unknown that how bending and twisting design on nanoscale building blocks affects the geometry of DNA tubes with micrometer length. Here, through targeted base pair deletion or insertion, the amount of bending deformation in building blocks is modulated by length gradient and the amount of twisting deformation is modulated by average twist density. This work systematically explores the independent effect and synergistic effect of two types of deformation on tube geometry, including diameter, chirality, and helical angles, via a streptavidin-labeling technique. The design rules enable the construction of DNA nanotubes with prescribed chirality and tailored diameters.


Assuntos
DNA
9.
Acc Chem Res ; 54(20): 3841-3849, 2021 10 19.
Artigo em Inglês | MEDLINE | ID: mdl-34582175

RESUMO

The rationale of the catalytic activity observed in experiments is a crucial task in fundamental catalysis studies. Efficient catalyst design relies on an accurate understanding of the origin of the activity at the atomic level. Theoretical studies have been widely developed to reach such a fundamental atomic scale understanding of catalytic activity. Current theories ascribe the catalytic activity to the geometric and electronic structure of the active site, in which the geometrical and electronic structure effects are derived from the equilibrium geometry of active sites characterizing the static property of the catalyst; however catalysts, especially in the form of nanoclusters, may present fluxional and dynamic structure under reaction conditions, and the effect of this fluxional behavior is not yet widely recognized. Therefore, this Account will focus on the fluxionality of the active sites, which is driven by thermal fluctuations under finite temperature.Under reaction conditions, nanocluster catalysts can readily restructure, either being promoted to another metastable isomer (named as plastic fluxionality) or presenting ample deformations around their equilibrium geometry (named as elastic fluxionality). This Account summarizes our recent studies on the fluxionality of the nanoclusters and how plastic and elastic fluxionalities play roles in highly efficient reaction pathways. Our results show that the low energy metastable isomers formed by plastic fluxionality can manifest high reactivity despite their minor occurrence probability in the mixture of catalyst isomers. In the end, the highly active metastable isomer may dominate the total observed reactivity. In addition, the isomerization between the global minimum structure and the highly active metastable isomer can be a central step in catalytic transformations in order to circumvent some difficult reaction steps and may govern the overall mechanism. In addition, the thermal fluctuation driven elastic fluxionality is also found to play a key role, complementary to plastic fluxionality. The elastic fluxionality creates substantial structural deformations of the active site, and these deformed geometries enable low activation energies and high catalytic activity, which cannot be found from the static equilibrium geometry of the catalyst. A dedicated global activity search algorithm is proposed to search for the optimal reaction pathway on fluxional nanoclusters. In summary, our studies demonstrate that thermal-driven fluxionality provides a different paradigm for understanding the high activity of nanoclusters under reaction conditions beyond the static description of geometric and electronic structure. We first summarize our previous results and then provide a perspective for further studies on how to investigate and take the advantage of the fluxional geometry of nanoclusters. We will defend in this Account that the static picture for the active site is not complete and might miss critical reaction pathways that are highly efficient and only open after thermally induced restructuring of the active site.

10.
Environ Res ; 213: 113700, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35716814

RESUMO

Increasing soil carbon (C) sequestration in paddy field and improving rice nitrogen use efficiency (NUE) are vital for sustainable agriculture and environmental protection. It was a benefit practice for achieving these goals by taken rice straw and organic manure managements. However, there is still need to further investigate the effects of different long-term fertilizer managements on soil C sequestration and NUE under the double-cropping rice system in southern of China. Therefore, the effects of different long-term (36-years) fertilizer practices on soil C sequestration and NUE under the double-cropping rice system in southern of China were investigated in the present paper. The field experiment was included four different fertilizer treatments: chemical fertilizer alone (MF), rice straw residue and chemical fertilizer (RF), 30% organic manure and 70% chemical fertilizer (OM), and without fertilizer input as a control (CK). This result indicated that soil C content at plough layer in paddy field with RF and OM treatments were increased, compared with MF and CK treatments. Besides input C directly into paddy field, soil original organic C accumulation with RF and OM treatments were increased by 1.54% and 3.01%, compared with MF treatment. This result indicated that soil TOC content increase rate and annual topsoil organic C sequestration rate in paddy field with RF and OM treatments increased by 55.56%, 88.89% and 48.05%, 76.62%, compared with MF treatment, respectively. Compared with MF treatment, NUE with RF and OM treatments increased by 10.43% and 22.61%, respectively, mainly due to increasing soil organic C. Grain yield of double-cropping rice with RF and OM treatments increased by 1009.5 and 1166.5 kg ha-1, compared with MF treatment, respectively. This result indicated that there was significantly correlation between NUE/NUENPK and TOC content with RF and OM treatments, at early rice and late rice growth seasons. Therefore, it was benefit practice for increasing soil carbon sequestration and improving rice NUE in the double-cropping rice system with long-term application of rice straw and organic manure managements.


Assuntos
Oryza , Solo , Agricultura , Carbono/análise , China , Fertilizantes/análise , Esterco/análise , Nitrogênio/análise , Oryza/química , Solo/química
11.
Angew Chem Int Ed Engl ; 61(49): e202211570, 2022 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-36216781

RESUMO

Lithium-sulfur batteries (LSBs) are still limited by the shuttle of lithium polysulfides (LiPS) and the slow Li-S reaction. Herein, we demonstrate that when using cobalt sulfide as a catalytic additive, an external magnetic field generated by a permanent magnet can significantly improve the LiPS adsorption ability and the Li-S reaction kinetics. More specifically, the results show both experimentally and theoretically how an electron spin polarization of Co ions reduces electron repulsion and enhances the degree of orbital hybridization, thus resulting in LSBs with unprecedented performance and stability. Under an external magnetic field, LSBs with 0.0084 % per cycle decay rate at 2 C during 8150 cycles are produced. Overall, this work not only demonstrates an effective strategy to promote LiPS adsorption and electrochemical conversion in LSBs at no additional energy cost but also enriches the application of the spin effect in the electrocatalysis fields.

12.
Sensors (Basel) ; 21(15)2021 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-34372486

RESUMO

Flying safely in complex urban environments is a challenge for unmanned aerial vehicles because path planning in urban environments with many narrow passages and few dynamic flight obstacles is difficult. The path planning problem is decomposed into global path planning and local path adjustment in this paper. First, a branch-selected rapidly-exploring random tree (BS-RRT) algorithm is proposed to solve the global path planning problem in environments with narrow passages. A cyclic pruning algorithm is proposed to shorten the length of the planned path. Second, the GM(1,1) model is improved with optimized background value named RMGM(1,1) to predict the flight path of dynamic obstacles. Herein, the local path adjustment is made by analyzing the prediction results. BS-RRT demonstrated a faster convergence speed and higher stability in narrow passage environments when compared with RRT, RRT-Connect, P-RRT, 1-0 Bg-RRT, and RRT*. In addition, the path planned by BS-RRT through the use of the cyclic pruning algorithm was the shortest. The prediction error of RMGM(1,1) was compared with those of ECGM(1,1), PCGM(1,1), GM(1,1), MGM(1,1), and GDF. The trajectory predicted by RMGM(1,1) was closer to the actual trajectory. Finally, we use the two methods to realize path planning in urban environments.


Assuntos
Algoritmos
13.
Angew Chem Int Ed Engl ; 60(9): 4764-4773, 2021 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-33206456

RESUMO

Single-atom catalysts (SACs) have become a prominent theme in heterogeneous catalysis, not least because of the potential fundamental insight into active sites. The desired level of understanding, however, is prohibited due to the inhomogeneity of most supported SACs and the lack of suitable tools for structure-activity correlation studies with atomic resolution. Herein, we describe the potency of electrospray ionization mass spectrometry (ESI-MS) to study molecularly defined SACs supported on polyoxometalates in catalytic reactions. We identified the exact composition of active sites and their evolution in the catalytic cycle during CO and alcohol oxidation reactions performed in the liquid phase. Critical information on metal-dependent reaction mechanisms, the key intermediates, the dynamics of active sites and even the stepwise activation barriers were obtained, which would be challenging to gather via prevailingly adopted techniques in SAC research. DFT calculations revealed intricate details of the reaction mechanisms, and strong synergies between ESI-MS defined SAC sites and electronic structure theory calculations become apparent.

14.
J Am Chem Soc ; 141(20): 8185-8197, 2019 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-31030515

RESUMO

Unlike nanostructured metal catalysts, supported single-atom catalysts (SACs) contain only atomically dispersed metal atoms, hinting at much more pronounced metal-support effects. Herein, we take a series of polyoxometalate-supported Pt catalysts as examples to quantitatively investigate the stability of Pt atoms on oxide supports and how the Pt-support interaction influences the catalytic performance. For this entire series, we show that the Pt atoms prefer to stay at a 4-fold hollow site of one polyoxometalate molecule and that the least adsorption energy to obtain sintering-resistant Pt SACs is 5.50 eV, which exactly matches the cohesive energy of bulk Pt metal. Further, we compared their catalytic performance in several hydrogenation reactions and simulated the reaction pathways of propene hydrogenation by density functional theory (DFT) calculations. Both experimental and theoretical approaches suggest that despite the Pt1-support interactions being different, the reaction pathways of various Pt1-polyoxometalate catalysts are very similar and their effective reaction barriers are close to each other and as low as 24 kJ/mol, indicating the possibility of obtaining SACs with improved stability without compromising activity. DFT calculations show that all reaction elementary steps take place only on the Pt atom without involving neighboring O atoms and that hydrogenation proceeds from the molecularly adsorbed H2 species. Pt SACs give a weaker H2 adsorption energy than Pt clusters or surfaces, resulting in small adsorption equilibrium constants and small apparent activation barriers, which agree between experiment and theory.

15.
J Chem Phys ; 151(19): 194703, 2019 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-31757161

RESUMO

Alumina supported Pt nanoclusters under a hydrogen environment play a crucial role in many heterogeneous catalysis applications. We conducted grand canonical genetic algorithm simulations for supported Pt8 clusters in a hydrogen gas environment to study the intracluster, cluster-support, and cluster-adsorbate interactions. Two alumina surfaces, α-Al2O3(0001) and γ-Al2O3(100), and two conditions, T = 600 °C, pH2 = 0.1 bar and T = 25 °C, pH2 = 1.0 bar, were considered corresponding to low and high hydrogen chemical potential µH, respectively. The low free energy ensemble of Pt8 is decorated by a medium (2-12 H), respectively, high (20-30 H), number of hydrogen atoms under equilibrium at low µH, respectively, high µH, and undergoes different morphological transformations on the two surfaces. On α-Al2O3(0001), Pt8 is mostly 3D but very fluxional in structure at low µH and converts to open one-layer 2D structures with minimal fluxionality at high µH, whereas on γ-Al2O3(100), the exact opposite occurs: Pt8 clusters present one-layer 2D shapes at low µH and switch to compact 3D shapes under high µH, during which the Pt8 cluster preserves moderate fluxionality. Further analysis reveals a similar Pt-Pt bond length increase when switching from low µH to high µH on both surfaces although morphological transformations are different. Electronic structure analysis shows the existence of bonding interactions between Pt and Lewis acidic Al3+ sites along with the Pt-O interaction, which implies the necessity to include Al neighbors to discuss the electronic structure of small Pt clusters.

16.
J Craniofac Surg ; 30(1): 74-80, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30028396

RESUMO

Although conventional microvascular anastomoses are well-studied, postoperative anastomotic stenoses remain a common surgical complication. The use of 2-octylcyanoacrylate to stabilize vascular anastomoses using a rabbit anastomosis model was investigated. A carotid artery anastomosis model was established in 20 New Zealand rabbits (2.5-3.0 kg): 10 underwent conventional anastomosis surgery with sutures only, while 10 underwent suture ligation, followed by the application of 2-octylcyanoacrylate. Vascular patency and pulse strength were observed after adhesive solidification. The artery diameter was measured preoperatively and at 5 minutes, 2 weeks, and 4 weeks postoperatively. An angiography was performed at 4 weeks postoperatively. Hyperplasia and the induced nitric oxide synthase (iNOS) content of the intima and media layers from the anastomotic stoma were assessed using immunohistochemistry. The artery inner diameter of experimental group decreased at each time point postoperatively (1.686 ±â€Š0.066 cm; 1.656 ±â€Š0.069 cm; 1.646 ±â€Š0.074 cm) (P ≤ 0.01). At 4 weeks postoperatively, the intima and the media around the anastomosis was both significantly thinner in the experimental group (13.21 ±â€Š0.84 µm; 234.86 ±â€Š13.84 µm) than in the control group (17.06 ±â€Š0.96 µm; 279.88 ±â€Š34.22 µm) (P < 0.05). At 4 weeks postsurgery, intravascular iNOS expression was increased in both groups but was higher in the experimental group (82.5% versus 47.5%). The above results indicated that 2-octylcyanoacrylate adhesive can inhibit stenosis of vascular anastomoses.


Assuntos
Anastomose Cirúrgica/efeitos adversos , Artérias Carótidas/cirurgia , Estenose das Carótidas/prevenção & controle , Cianoacrilatos/uso terapêutico , Complicações Pós-Operatórias/prevenção & controle , Adesivos Teciduais/uso terapêutico , Anastomose Cirúrgica/métodos , Animais , Estenose das Carótidas/etiologia , Hiperplasia , Masculino , Complicações Pós-Operatórias/etiologia , Coelhos , Suturas , Túnica Íntima , Grau de Desobstrução Vascular
17.
J Am Chem Soc ; 140(8): 2812-2820, 2018 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-29424224

RESUMO

Reactivity studies on catalytic transition metal clusters are usually performed on a single global minimum structure. With the example of a Pt13 cluster under a pressure of hydrogen, we show from first-principle calculations that low energy metastable structures of the cluster can play a major role for catalytic reactivity and that hence consideration of the global minimum structure alone can severely underestimate the activity. The catalyst is fluxional with an ensemble of metastable structures energetically accessible at reaction conditions. A modified genetic algorithm is proposed to comprehensively search for the low energy metastable ensemble (LEME) structures instead of merely the global minimum structure. In order to reduce the computational cost of density functional calculations, a high dimensional neural network potential is employed to accelerate the exploration. The presence and influence of LEME structures during catalysis is discussed by the example of H covered Pt13 clusters for two reactions of major importance: hydrogen evolution reaction and methane activation. The results demonstrate that although the number of accessible metastable structures is reduced under reaction condition for Pt13 clusters, these metastable structures can exhibit high activity and dominate the observed activity due to their unique electronic or structural properties. This underlines the necessity of thoroughly exploring the LEME structures in catalysis simulations. The approach enables one to systematically address the impact of isomers in catalysis studies, taking into account the high adsorbate coverage induced by reaction conditions.

18.
Bioorg Med Chem Lett ; 28(17): 2957-2960, 2018 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-30001917

RESUMO

In this study, Complex I inhibitor R419 was firstly revealed to have significant anticancer activity against HepG2 cells (IC50 = 5.2 ±â€¯0.9 µM). Based on this finding, a series of R419 derivatives were synthesized and biologically evaluated. As results, 9 derivatives were found to have obvious anticancer activity. Among them, H20 exhibited the most potent activity (IC50 = 2.8 ±â€¯0.4 µM). Mechanism study revealed that H20 caused severe depletion of cellular ATP, dose-dependently activated AMPK, decreased Bcl-2/Bax ratio and induced necrotic cell death. Most importantly, H20 displayed definite inhibitory activity against Complex I.


Assuntos
Antineoplásicos/farmacologia , Complexo I de Transporte de Elétrons/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Piperidinas/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Morte Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Complexo I de Transporte de Elétrons/metabolismo , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Células Hep G2 , Humanos , Estrutura Molecular , Piperidinas/síntese química , Piperidinas/química , Relação Estrutura-Atividade
20.
Zhongguo Yi Liao Qi Xie Za Zhi ; 41(3): 208-212, 2017 May 30.
Artigo em Zh | MEDLINE | ID: mdl-29862770

RESUMO

In the background of the high incidence of vascular injury in wartime, this paper introduces the characteristics of vascular injury in war environment and the development of early treatment technique of vascular injury applied in wars since World War Ⅱ. Then, the advantages and limitations of various treatment techniques are also analyzed. Finally, The development of technology and research direction are summarized and prospected.


Assuntos
Lesões do Sistema Vascular/terapia , Guerra , História do Século XX , História do Século XXI , Humanos , Incidência , Lesões do Sistema Vascular/história
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA