Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 280
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Proc Natl Acad Sci U S A ; 121(5): e2315362121, 2024 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-38261614

RESUMO

Carbon-based single-atom catalysts, a promising candidate in electrocatalysis, offer insights into electron-donating effects of metal center on adjacent atoms. Herein, we present a practical strategy to rationally design a model catalyst with a single zinc (Zn) atom coordinated with nitrogen and sulfur atoms in a multilevel carbon matrix. The Zn site exhibits an atomic interface configuration of ZnN4S1, where Zn's electron injection effect enables thermal-neutral hydrogen adsorption on neighboring atoms, pushing the activity boundaries of carbon electrocatalysts toward electrochemical hydrogen evolution to an unprecedented level. Experimental and theoretical analyses confirm the low-barrier Volmer-Tafel mechanism of proton reduction, while the multishell hollow structures facilitate the hydrogen evolution even at high current intensities. This work provides insights for understanding the actual active species during hydrogen evolution reaction and paves the way for designing high-performance electrocatalysts.

2.
Methods ; 228: 38-47, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38772499

RESUMO

Human leukocyte antigen (HLA) molecules play critically significant role within the realm of immunotherapy due to their capacities to recognize and bind exogenous antigens such as peptides, subsequently delivering them to immune cells. Predicting the binding between peptides and HLA molecules (pHLA) can expedite the screening of immunogenic peptides and facilitate vaccine design. However, traditional experimental methods are time-consuming and inefficient. In this study, an efficient method based on deep learning was developed for predicting peptide-HLA binding, which treated peptide sequences as linguistic entities. It combined the architectures of textCNN and BiLSTM to create a deep neural network model called APEX-pHLA. This model operated without limitations related to HLA class I allele variants and peptide segment lengths, enabling efficient encoding of sequence features for both HLA and peptide segments. On the independent test set, the model achieved Accuracy, ROC_AUC, F1, and MCC is 0.9449, 0.9850, 0.9453, and 0.8899, respectively. Similarly, on an external test set, the results were 0.9803, 0.9574, 0.8835, and 0.7863, respectively. These findings outperformed fifteen methods previously reported in the literature. The accurate prediction capability of the APEX-pHLA model in peptide-HLA binding might provide valuable insights for future HLA vaccine design.


Assuntos
Antígenos de Histocompatibilidade Classe I , Peptídeos , Ligação Proteica , Humanos , Antígenos de Histocompatibilidade Classe I/imunologia , Antígenos de Histocompatibilidade Classe I/metabolismo , Peptídeos/química , Peptídeos/imunologia , Aprendizado Profundo , Antígenos HLA/imunologia , Antígenos HLA/genética , Redes Neurais de Computação , Biologia Computacional/métodos
3.
Carcinogenesis ; 2024 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-39234990

RESUMO

Adenocarcinoma of the esophagogastric junction (AEG) has received widespread attention because of its increasing incidence. However, the molecular mechanism underlying tumor progression remains unclear. Here, we report that the downregulation of Ubiquitin-specific peptidase 49 (USP49) promotes ferroptosis in OE33 and OE19 cells, thereby inhibiting cell proliferation in vitro and in vivo, whereas the overexpression of USP49 had the opposite effect. In addition, USP49 downregulation promoted AEG cell radiotherapy sensitivity. Moreover, overexpression of Glutathione PeroXidase 4 (GPX4) reversed the ferroptosis and proliferation inhibition induced by USP49 knockdown. Mechanistically, USP49 deubiquitinates and stabilizes Shc SH2-domain binding protein 1 (SHCBP1), subsequently facilitating the entry of ß-catenin into the nucleus to enhance GPX4 transcriptional expression. Finally, high USP49 expression was correlated with shorter overall survival in patients with AEG. In summary, our findings identify USP49 as a novel regulator of ferroptosis in AEG cells, indicating that USP49 may be a potential therapeutic target in AEG.

4.
J Pharmacol Exp Ther ; 388(1): 156-170, 2024 01 02.
Artigo em Inglês | MEDLINE | ID: mdl-37918855

RESUMO

Spleen tyrosine kinase (Syk) is an intracellular tyrosine kinase involved in the signal transduction in immune cells mainly. Its aberrant regulation is associated with diversified allergic disorders, autoimmune diseases and B cell malignancies. Therefore, inhibition of Syk is considered a reasonable approach to treat autoimmune/inflammatory diseases and B cell malignancies. Here we described the preclinical characterization of sovleplenib, a novel, highly potent and selective, oral Syk inhibitor, in several rodent autoimmune disease models. Sovleplenib potently inhibited Syk activity in a recombinant enzymatic assay and Syk-dependent cellular functions in various immune cell lines and human whole blood in vitro. Furthermore, sovleplenib, by oral administration, demonstrated strong in vivo efficacies in murine models of immune thrombocytopenia (ITP), autoimmune hemolytic anemia (AIHA), and chronic graft-versus-host disease (cGVHD), and a rat model of collagen induced arthritis (CIA) respectively, in a dose-dependent manner. Collectively, these results clearly supported sovleplenib as a therapeutic agent in the treatment of autoimmune diseases. Sovleplenib is being globally developed for ITP (Phase III, NCT05029635, Phase Ib/II, NCT03951623), wAIHA (Phase II/III, NCT05535933) and B-cell lymphoma (Phase I, NCT02857998, NCT03779113). SIGNIFICANCE STATEMENT: Syk is a key mediator of signaling pathways downstream of a wide array of receptors important for immune functions, including the B cell receptor, immunoglobulin receptors bearing Fc receptors. Inhibition of Syk could provide a novel therapeutic approach for autoimmune diseases and hematologic malignancies. The manuscript describes the preclinical pharmacology characterization of sovleplenib, a novel Syk inhibitor, in enzymatic and cellular assays in vitro and several murine autoimmune disease models in vivo.


Assuntos
Doenças Autoimunes , Neoplasias , Ratos , Camundongos , Humanos , Animais , Proteínas Tirosina Quinases , Quinase Syk , Transdução de Sinais , Inibidores de Proteínas Quinases/farmacologia , Doenças Autoimunes/tratamento farmacológico , Neoplasias/tratamento farmacológico
5.
Virol J ; 21(1): 96, 2024 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-38671532

RESUMO

BACKGROUND: There is still limited research on the prognostic value of Presepsin as a biomarker for predicting the outcome of COVID-19 patients. Additionally, research on the combined predictive value of Presepsin with clinical scoring systems and inflammation markers for disease prognosis is lacking. METHODS: A total of 226 COVID-19 patients admitted to Beijing Youan Hospital's emergency department from May to November 2022 were screened. Demographic information, laboratory measurements, and blood samples for Presepsin levels were collected upon admission. The predictive value of Presepsin, clinical scoring systems, and inflammation markers for 28-day mortality was analyzed. RESULTS: A total of 190 patients were analyzed, 83 (43.7%) were mild, 61 (32.1%) were moderate, and 46 (24.2%) were severe/critically ill. 23 (12.1%) patients died within 28 days. The Presepsin levels in severe/critical patients were significantly higher compared to moderate and mild patients (p < 0.001). Presepsin showed significant predictive value for 28-day mortality in COVID-19 patients, with an area under the ROC curve of 0.828 (95% CI: 0.737-0.920). Clinical scoring systems and inflammation markers also played a significant role in predicting 28-day outcomes. After Cox regression adjustment, Presepsin, qSOFA, NEWS2, PSI, CURB-65, CRP, NLR, CAR, and LCR were identified as independent predictors of 28-day mortality in COVID-19 patients (all p-values < 0.05). Combining Presepsin with clinical scoring systems and inflammation markers further enhanced the predictive value for patient prognosis. CONCLUSION: Presepsin is a favorable indicator for the prognosis of COVID-19 patients, and its combination with clinical scoring systems and inflammation markers improved prognostic assessment.


Assuntos
Biomarcadores , COVID-19 , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Biomarcadores/sangue , COVID-19/mortalidade , COVID-19/sangue , COVID-19/diagnóstico , Inflamação/sangue , Receptores de Lipopolissacarídeos/sangue , Fragmentos de Peptídeos/sangue , Valor Preditivo dos Testes , Prognóstico , Curva ROC , SARS-CoV-2/fisiologia , Índice de Gravidade de Doença
6.
Cell Commun Signal ; 22(1): 168, 2024 03 07.
Artigo em Inglês | MEDLINE | ID: mdl-38454413

RESUMO

BACKGROUND: The effectiveness of anti-programmed cell death protein 1(PD-1)/programmed cell death 1 ligand 1(PD-L1) therapy in treating certain types of cancer is associated with the level of PD-L1. However, this relationship has not been observed in colorectal cancer (CRC), and the underlying regulatory mechanism of PD-L1 in CRC remains unclear. METHODS: Binding of TMEM160 to PD-L1 was determined by co-immunoprecipitation (Co-IP) and GST pull-down assay.The ubiquitination levels of PD-L1 were verified using the ubiquitination assay. Phenotypic experiments were conducted to assess the role of TMEM160 in CRC cells. Animal models were employed to investigate how TMEM160 contributes to tumor growth.The expression and clinical significance of TMEM160 and PD-L1 in CRC tissues were evaluated by immunohistochemistry(IHC). RESULTS: In our study, we made a discovery that TMEM160 interacts with PD-L1 and plays a role in stabilizing its expression within a CRC model. Furthermore, we demonstrated that TMEM160 hinders the ubiquitination-dependent degradation of PD-L1 by competing with SPOP for binding to PD-L1 in CRC cells. Regarding functionality, the absence of TMEM160 significantly inhibited the proliferation, invasion, metastasis, clonogenicity, and radioresistance of CRC cells, while simultaneously enhancing the cytotoxic effect of CD8 + T cells on tumor cells. Conversely, the upregulation of TMEM160 substantially increased these capabilities. In severely immunodeficient mice, tumor growth derived from lentiviral vector shTMEM160 cells was lower compared with that derived from shNC control cells. Furthermore, the downregulation of TMEM160 significantly restricted tumor growth in immune-competent BALB/c mice. In clinical samples from patients with CRC, we observed a strong positive correlation between TMEM160 expression and PD-L1 expression, as well as a negative correlation with CD8A expression. Importantly, patients with high TMEM160 expression exhibited a worse prognosis compared with those with low or no TMEM160 expression. CONCLUSIONS: Our study reveals that TMEM160 inhibits the ubiquitination-dependent degradation of PD-L1 that is mediated by SPOP, thereby stabilizing PD-L1 expression to foster the malignant progress, radioresistance, and immune evasion of CRC cells. These findings suggest that TMEM160 holds potential as a target for the treatment of patients with CRC.


Assuntos
Neoplasias Colorretais , Animais , Humanos , Camundongos , Antígeno B7-H1/metabolismo , Linfócitos T CD8-Positivos , Neoplasias Colorretais/patologia , Linfócitos do Interstício Tumoral , Proteínas Nucleares , Proteínas Repressoras , Evasão Tumoral
7.
J Neurooncol ; 2024 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-39276177

RESUMO

INTRODUCTION: Spinal chondrosarcoma exhibits higher invasiveness and a worse prognosis compared to chondrosarcoma in the extremities. The prognosis and therapeutic plan vary greatly among different pathological subtypes of chondrosarcoma. This study aimed to analyze the differences in clinical characteristics, molecular features, therapeutic effects, and prognostic factors among the subtypes of chondrosarcoma in the spine. METHODS: A retrospective review was conducted on 205 patients with spinal chondrosarcoma. The clinical features and immunohistochemical (IHC) markers were compared among the pathological subtypes of chondrosarcoma grade 1, grade 2, grade 3, mesenchymal chondrosarcoma (MCS), dedifferentiated chondrosarcoma (DCS), and clear cell chondrosarcoma (CCCS). Chondrosarcoma grade 1/2/3 are collectively referred to as conventional chondrosarcoma (CCS) for multivariate survival analysis. Univariate and multivariate analyses were performed to investigate independent prognostic factors for overall survival (OS) and recurrence-free survival (RFS) in patients with spinal chondrosarcoma. Furthermore, independent prognostic factors for OS and RFS were identified in CCS and MCS. RESULTS: MCS patients were younger than the other subtypes. Patients with chondrosarcoma grade 1/2 had better OS than those with chondrosarcoma grade 3, MCS and DCS, while only chondrosarcoma grade 1 patients showed better RFS than chondrosarcoma grade 2/3, MCS and DCS patients. Ki-67 index was higher in chondrosarcoma grade 3, MCS and DCS than chondrosarcoma grade 1/2. The comparison of IHC markers further highlighted the overexpression of P53/MDM2 in MCS and DCS. Gross total resection, including en-bloc and piecemeal resection, significantly improved OS and RFS for CCS patients, while only en-bloc resection significantly improved the prognosis of MCS patients. Chemotherapy appeared to be important for the OS of MCS patients. CONCLUSION: P53/MDM2 pathway was upregulated in MCS and DCS compared to chondrosarcoma grade 1/2. Radical tumor resection is crucial for the treatment of spinal chondrosarcoma, while MCS patients require further comprehensive treatments perioperatively.

8.
Environ Sci Technol ; 58(1): 410-420, 2024 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-38154084

RESUMO

SiO2 nanoparticles (SiO2NPs) are most widely available and coexisting with DOM at the mineral-water interface; however, the role of SiO2NPs in DOM fractionation and the underlying mechanisms have not been fully understood. Using Fourier transform ion cyclotron resonance mass spectrometry, combined with Fourier transform infrared spectroscopy and X-ray adsorption fine structure spectroscopy, was employed to investigate the adsorptive fractionation of litter layer-derived DOM on goethite coexisting with SiO2NPs under different pH conditions. Results indicated that the inhibitory effect of the coexisting SiO2NPs on OM sorbed by goethite was waning as environmental pH increased due to the reduced steric interactions and the concurrent elevated hydrogen bonding/hydrophobic partitioning interactions on the goethite surface. We observed the coexisting SiO2NPs inhibited the adsorption of high carboxylic-containing condensed aromatic/aromatics compounds on goethite under different pH conditions while improving the adsorption of highly unsaturated aliphatic/phenolic and carbohydrate-like compounds in an alkaline and/or circumneutral environment. More nitrogen-containing structures may favor the adsorption of phenolic and nonaromatic compounds to goethite by counteracting the negative effect of SiO2NPs. These findings suggest that DOM sequestration may be significantly regulated by the coexisting SiO2NPs at the mineral-water interface, which may further influence the carbon-nitrogen cycling and contaminant fate in natural environments.


Assuntos
Matéria Orgânica Dissolvida , Dióxido de Silício , Adsorção , Minerais/química , Compostos Orgânicos , Fenóis , Água , Nitrogênio
9.
BMC Musculoskelet Disord ; 25(1): 701, 2024 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-39227785

RESUMO

BACKGROUND: The Wiltse approach has been extensively employed in thoracolumbar surgeries due to its minimal muscle damage. However, in the middle and lower thoracic spine, the conventional Wiltse approach necessitates the severance of the latissimus dorsi and trapezius muscles, potentially leading to muscular injury. Consequently, we propose a modified Wiltse approach for the middle and lower thoracic vertebrae, which may further mitigate muscular damage. METHODS: From May 2018 to April 2022, 60 patients with spinal fractures in the middle and lower thoracic vertebrae (T5-12) were enrolled in this study. Thirty patients underwent surgery using the modified Wiltse approach (Group A), while the remaining 30 patients received traditional posterior surgery (Group B). The observation indices included operation time, intraoperative blood loss, incision length, number of C-arm exposures, postoperative drainage, postoperative ambulation time, discharge time, as well as preoperative and postoperative Cobb's angle, percentage of anterior vertebral body height (PAVBH), visual analog scale (VAS) Score, and Oswestry disability index (ODI). RESULTS: Compared to the traditional posterior approach, the modified Wiltse approach demonstrated significant advantages in operation time, intraoperative blood loss, length of incision, postoperative ambulation time, postoperative drainage, and discharge time, as well as postoperative VAS and ODI scores. No significant differences were observed between the two groups in terms of number of C-arm exposures, postoperative Cobb's angle, or postoperative PAVBH. CONCLUSION: We propose a modification of the Wiltse approach for the middle and lower thoracic vertebral regions, which may further minimize muscular damage and facilitate the recovery of patients who have undergone surgery in the middle and lower thoracic vertebrae.


Assuntos
Fraturas da Coluna Vertebral , Vértebras Torácicas , Humanos , Vértebras Torácicas/cirurgia , Vértebras Torácicas/lesões , Vértebras Torácicas/diagnóstico por imagem , Masculino , Feminino , Fraturas da Coluna Vertebral/cirurgia , Fraturas da Coluna Vertebral/diagnóstico por imagem , Pessoa de Meia-Idade , Adulto , Estudos de Casos e Controles , Idoso , Duração da Cirurgia , Resultado do Tratamento , Perda Sanguínea Cirúrgica , Fixação Interna de Fraturas/métodos , Estudos Retrospectivos
10.
Sensors (Basel) ; 24(6)2024 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-38544076

RESUMO

Radio frequency identification (RFID) is well known as an identification, track, and trace approach and is considered to be the key physical layer technology for the industrial internet of things (IIoT). However, IIoT systems have to introduce additional complex sensor networks for pervasive monitoring, and there are still challenges related to item-level sensing and data recording. To overcome the shortage, this work proposes an artificial intelligence (AI)-assisted RFID-based multi-sensing technology. Both passive and semi-passive RFID tag-integrated multi-sensors are developed. The main contributions and the novelty of this investigation are as follows. A UHF RFID tag-integrated multi-sensor with a boosted charge pump is proposed; it enables high RF signal sensitivity and a long operational range. The whole hardware design, including the antenna and energy harvester, are studied. Moreover, a demonstration with real-world ham product sensing data is conducted. This work also proposes and successfully demonstrates the integration of machine learning algorithms, specifically the NARX neural network, with RFID sensing data for food product quality assessment and sensing (QAS). This application of machine learning to RFID-generated data for quality assessment is also a novel aspect of the research. The deployment of an autoregressive model with an exogenous input (NARX) neural network model, tailored for nonlinear processes, emerges as the most effective, achieving a root mean square error (RMSE) of 0.007 and an R-squared value of 0.99 for ham product QAS. By deploying the technology, low-cost, timely, and flexible product QAS can be achieved in manufacturing industries, which helps product quality improvement and the optimization of the manufacturing line and supply chain.

11.
J Environ Manage ; 364: 121451, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38878576

RESUMO

A double-decision optimization model based on the road grade optimization strategy and considered comprehensive traffic environment benefit is proposed to control the traffic noise. The upper-level model maximizes the comprehensive traffic environment benefit, including network noise emission and traffic efficiency. Adjusting the emphasis on noise optimization benefits and traffic efficiency in road network planning through setting weights. The lower-level resolves the question of network traffic flow assignment using a stochastic user-equilibrium model. The increase of traffic environment demand, network noise emissions decrease and travel time rises. In the case, with a low environmental requirement (weighting with 1.1), the sound pressure emission of the network decreases by 9.23% with only a 4.01% increase in travel time. Under the high environmental requirement (weighting with 0.2), the sound pressure decreases by 26.8%, but the travel time rises by as high as 30.9%. The network is optimized towards road grade degradation and is the first to optimize the arterial roads. In addition, it is found that the influence of speed on traffic noise is greater than that of traffic volume through case validation. This method proposing traffic noise optimization strategies at the road network planning level provides technical support for the proactive governance of traffic noise pollution and the improvement of traffic sound environment quality.


Assuntos
Ruído dos Transportes , Ruído dos Transportes/prevenção & controle , Ruído , Modelos Teóricos , Cidades
12.
Angew Chem Int Ed Engl ; 63(7): e202316762, 2024 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-38038365

RESUMO

Understanding the correlation between the structural evolution of electrocatalysts and their catalytic activity is both essential and challenging. In this study, we investigate this correlation in the context of the oxygen evolution reaction (OER) by examining the influence of structural disorder during and after dynamic structural evolution on the OER activity of Fe-Ni (oxy)hydroxide catalysts using operando X-ray absorption spectroscopy, alongside other experiments and theoretical calculations. The Debye-Waller factors obtained from extended X-ray absorption fine structure analyses reflect the degree of structural disorder and exhibit a robust correlation with the intrinsic OER activities of the electrocatalysts. The enhanced OER activity of in situ-generated metal (oxy)hydroxides derived from different pre-catalysts is linked to increased structural disorder, offering a promising approach for designing efficient OER electrocatalysts. This strategy may inspire similar investigations in related electrocatalytic energy-conversion systems.

13.
Angew Chem Int Ed Engl ; : e202411218, 2024 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-39137124

RESUMO

Chemical modification via functional dopants in carbon materials holds great promise for elevating catalytic activity and stability. To gain comprehensive insights into the pivotal mechanisms and establish structure-performance relationships, especially concerning the roles of dopants, remains a pressing need. Herein, we employ computational simulations to unravel the catalytic function of heteroatoms in the acidic oxygen evolution reaction (OER), focusing on a physical model of high-electronegative F and N co-doped carbon matrix. Theoretical and experimental findings elucidate that the enhanced activity originates from the F and pyridinic-N (Py-N) species that achieve carbon activation. This activated carbon significantly lowers the conversion energy barrier from O* to OOH*, shifts the potential-limiting step from OOH* formation to O* generation, and ultimately optimizes the energy barrier of the potential-limiting step. This wok elucidates that the critical role of heteroatoms in catalyzing the reaction and unlocks the potential of carbon materials for acidic OER.

14.
Hum Brain Mapp ; 44(6): 2191-2208, 2023 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-36637216

RESUMO

The multilayer dynamic network model has been proposed as an effective method to understand the brain function. In particular, derived from the definition of clustering coefficient in static networks, the temporal clustering coefficient provides a direct measure of the topological stability of dynamic brain networks and shows potential in predicting altered brain functions. However, test-retest reliability and demographic-related effects on this measure remain to be evaluated. Using a data set from the Human Connectome Project (157 male and 180 female healthy adults; 22-37 years old), the present study investigated: (1) the test-retest reliability of temporal clustering coefficient across four repeated resting-state functional magnetic resonance imaging scans as measured by intraclass correlation coefficient (ICC); and (2) sex- and age-related effects on temporal clustering coefficient. The results showed that (1) the temporal clustering coefficient had overall moderate test-retest reliability (ICC > 0.40 over a wide range of densities) at both global and subnetwork levels, (2) female subjects showed significantly higher temporal clustering coefficient than males at both global and subnetwork levels, particularly within the default-mode and subcortical regions, and (3) temporal clustering coefficient of the subcortical subnetwork was positively correlated with age in young adults. The results of sex effects were robustly replicated in an independent REST-meta-MDD data set, while the results of age effects were not. Our findings suggest that the temporal clustering coefficient is a relatively reliable and reproducible approach for identifying individual differences in brain function, and provide evidence for demographically related effects on the human brain dynamic connectomes.


Assuntos
Conectoma , Imageamento por Ressonância Magnética , Adulto Jovem , Humanos , Masculino , Feminino , Adulto , Reprodutibilidade dos Testes , Imageamento por Ressonância Magnética/métodos , Encéfalo/diagnóstico por imagem , Conectoma/métodos , Análise por Conglomerados
15.
Small ; 19(25): e2301235, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36922746

RESUMO

Here, an ultra-highly active Ni-MOF-5 catalyst with high Ni loading for ethylene dimerization is reported. The Ni-MOF-5 catalysts are synthesized by a facile one-pot co-precipitation method at room temperature, where Ni2+ replaces Zn2+ in MOF-5. Unlike Zn2+ with tetrahedral coordination in MOF-5, Ni2+ is coordinated with extra solvent molecules except for four-oxygen from the framework. After removing coordinated solvent molecules, Ni-MOF-5 achieves an ethylene turnover frequency of 352 000 h-1 , corresponding to 9040 g of product per gram of catalyst per hour, at 35 °C and 50 bar, far exceeding the activities of all reported heterogeneous catalysts. The high Ni loading and full exposure structure account for the excellent catalytic performance. Isotope labeling experiments reveal that the catalytic process follows the Cossee-Arlman mechanism, rationalizing the high activity and selectivity of the catalyst. These results demonstrate that Ni-MOF-5 catalysts are very promising for industrial catalytic ethylene dimerization.

16.
Mol Cell Biochem ; 478(4): 697-706, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36036335

RESUMO

Diabetic retinopathy (DR), a microvascular complication characterized by abnormal angiogenesis, is the most common reason for irreversible blindness. Glycoprotein non-metastatic melanoma protein B (GPNMB), as a transmembrane protein, was found to be associated with angiogenesis. This study aims to investigate the role of GPNMB in DR. The levels of GPNMB and Integrin ß1 were detected by real-time PCR and western blot and were found to be increased in human retinal microvascular endothelial cells (HRMECs) with high glucose (HG, 25 mmol/L) treatment. Knockdown of GPNMB was mediated by lentivirus carrying shRNA targeting GPNMB in vivo and in vitro. Functional experiments, including cell counting kit-8 (CCK-8), scratch, and tube formation assays, showed the anti-proliferative, anti-migrative, and anti-angiogenic roles of GPNMB knockdown in HRMECs using the lentivirus system following HG challenge. Additionally, increased GPNMB levels were detected in the retina of DR rats induced by a single intraperitoneal injection of streptozotocin (60 mg/kg) using real-time PCR, western blot, and immunofluorescence assays. Downregulation of GPNMB inhibited the angiogenesis and vascular endothelial growth factor production in the retina of rats with DR. Furthermore, overexpression of Integrin ß1 led to increased angiogenesis in DR. Integrin ß1 was indicated as a target protein of GPNMB. Upregulated-Integrin ß1 restored GPNMB knockdown-induced inhibition of cell viability, migration, and tube formation in HRMECs. In conclusion, we provide evidence for the angiogenic role of GPNMB and demonstrate that silencing GPNMB may represent a therapeutic potential in the treatment of DR.


Assuntos
Diabetes Mellitus , Retinopatia Diabética , MicroRNAs , Humanos , Ratos , Animais , Retinopatia Diabética/metabolismo , Regulação para Baixo , Células Endoteliais/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo , Integrina beta1/genética , Integrina beta1/metabolismo , Glicoproteínas/metabolismo , Glucose/farmacologia , Glucose/metabolismo , MicroRNAs/genética , Proliferação de Células , Diabetes Mellitus/metabolismo , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismo
17.
Faraday Discuss ; 242(0): 429-442, 2023 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-36173024

RESUMO

Activity, cost, and durability are the trinity of catalysis research for the electrochemical oxygen reduction reaction (ORR). While studies towards increasing activity and reducing cost of ORR catalysts have been carried out extensively, much effort is needed in durability investigation of highly active ORR catalysts. In this work, we examined the stability of a trimetallic PtPdCu catalyst that has demonstrated high activity and incredible durability during ORR using density functional theory (DFT) based computations. Specifically, we studied the processes of dissolution/deposition and diffusion between the surface and inner layer of Cu species of Pt20Pd20Cu60 catalysts at electrode potentials up to 1.2 V to understand their role towards stabilizing Pt20Pd20Cu60 catalysts. The results show there is a dynamic Cu surface composition range that is dictated by the interplay of the four processes, dissolution, deposition, diffusion from the surface to inner layer, and diffusion from the inner layer to the surface of Cu species, in the stability and observed oscillation of lattice constants of Cu-rich PtPdCu nanoalloys.

18.
J Chem Inf Model ; 63(24): 7655-7668, 2023 Dec 25.
Artigo em Inglês | MEDLINE | ID: mdl-38049371

RESUMO

The development of potentially active peptides for specific targets is critical for the modern pharmaceutical industry's growth. In this study, we present an efficient computational framework for the discovery of active peptides targeting a specific pharmacological target, which combines a conditional variational autoencoder (CVAE) and a classifier named TCPP based on the Transformer and convolutional neural network. In our example scenario, we constructed an active cyclic peptide library targeting interleukin-17C (IL-17C) through a library-based in vitro selection strategy. The CVAE model is trained on the preprocessed peptide data sets to generate potentially active peptides and the TCPP further screens the generated peptides. Ultimately, six candidate peptides predicted by the model were synthesized and assayed for their activity, and four of them exhibited promising binding affinity to IL-17C. Our study provides a one-stop-shop for target-specific active peptide discovery, which is expected to boost up the process of peptide drug development.


Assuntos
Interleucina-17 , Peptídeos Cíclicos , Peptídeos Cíclicos/farmacologia , Interleucina-17/metabolismo , Peptídeos
19.
Ecotoxicol Environ Saf ; 258: 114959, 2023 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-37121079

RESUMO

The application of organic fertilizers caused large amounts of dissolved organic matter (DOM) entering the soil environment and influencing the behaviors and fates of heavy metals. Here, we investigated the molecular weight-dependent (high molecular weight [HMW], 1 kDa-0.7 µm; low molecular weight [LMW], <1 kDa) compositions and lead (Pb) binding behaviors of DOM derived from sheep manure-based (SMOF) and shrimp peptide-based organic fertilizers (SPOF) using chromophoric and fluorescent spectroscopy, Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) and two-dimensional correlation spectroscopy (2D-COS). Results showed that SMOF released more DOM with higher aromaticity and hydrophobicity, containing more fluvic-like components, carboxylic-rich alicyclic molecules (CRAMs) and lignin phenolic compounds compared to SPOF-DOM with more microbially-transformed heteroatom-containing compounds (CHON, CHONS and CHOS). Furthermore, there was more aromatic compounds with ample carboxyl and hydroxyl groups in HMW-DOM but abundant protein-like components and heteroatom-containing compounds (CHONS and CHOS) in LMW-DOM. SMOF-DOM exhibited more obvious MW-dependent heterogeneity in molecular components compared to SPOF-DOM with higher molecular diversity. Moreover, 2D-COS indicated phenol and carboxyl groups in SMOF-DOM and polysaccharides in SPOF-DOM exhibited superior binding affinities for Pb. Pb binding to HMW-DOM derived from SMOF first occurred in the phenolic groups in fulvic-like substances, while polysaccharides in LMW-DOM first participated in the binding of Pb. In contrast, irrespective of MWs, polysaccharides and humic-like substances with aromatic (CC) groups in SPOF-DOM displayed a faster response to Pb. Furthermore, the polysaccharides which preferentially participated in the binding of Pb to SPOF-DOM and SMOF-derived LMW-DOM may pose a higher risk of Pb in the environment. These results were helpful to understand the effects of sources and size-dependent compositions of DOM on the associated risks of heavy metals in the environments.


Assuntos
Matéria Orgânica Dissolvida , Metais Pesados , Animais , Ovinos , Fertilizantes/análise , Chumbo , Substâncias Húmicas/análise , Metais Pesados/química , Espectrometria de Fluorescência/métodos
20.
Sensors (Basel) ; 23(3)2023 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-36772119

RESUMO

Partial discharge (PD) localization is important for monitoring and maintaining high-voltage equipment, which can help to prevent accidents. In this work, an acoustic localization sensor based on microelectromechanical system (MEMS) microphone array is proposed, which can detect and locate the partial discharge through a beam-forming algorithm. The MEMS microphone array consists of eight commercial MEMS microphones (SPV08A0LR5H-1, Knowles Electronics, IL, USA) with an aperture size of about 0.1 m × 0.1 m, allowing for a small hardware size and low cost. In order to optimize the acoustic performance of the array, a random array topology is designed. The simulation analysis indicates that the designed random topology is superior to several commonly used topologies. In terms of the localization algorithm, a deconvolution method called Fourier-based fast iterative shrinkage thresholding algorithm (FFT-FISTA) is applied. Simulation and experiment results demonstrate that FFT-FISTA used in the proposed acoustic localization sensor has significant advantages over the conventional beam-forming algorithm on spatial resolution and sidelobe suppression. Experimental results also show that the average localization error of the proposed scheme is about 0.04 m, which can meet the demands of practical application.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA