Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 30
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
País de afiliação
Intervalo de ano de publicação
1.
BMC Gastroenterol ; 24(1): 85, 2024 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-38408903

RESUMO

BACKGROUND: Functional performance as measured by the Karnofsky Performance Status (KPS) scale has been linked to the outcomes of liver transplant patients; however, the effect of KPS on the outcomes of the hepatocellular carcinoma (HCC) liver transplant population has not been fully elucidated. We aimed to investigate the association between pre-transplant KPS score and long-term outcomes in HCC patients listed for liver transplantation. METHODS: Adult HCC candidates listed on the Scientific Registry of Transplant Recipients (SRTR) database from January 1, 2011 to December 31, 2017 were grouped into group I (KPS 80-100%, n = 8,379), group II (KPS 50-70%, n = 8,091), and group III (KPS 10-40%, n = 1,256) based on percentage KPS score at listing. Survival was compared and multivariable analysis was performed to identify independent predictors. RESULTS: Patients with low KPS score had a higher risk of removal from the waiting list. The 5-year intent-to-treat survival was 57.7% in group I, 53.2% in group II and 46.7% in group III (P < 0.001). The corresponding overall survival was 77.6%, 73.7% and 66.3% in three groups, respectively (P < 0.001). Multivariable analysis demonstrated that KPS was an independent predictor of intent-to-treat survival (P < 0.001, reference group I; HR 1.19 [95%CI 1.07-1.31] for group II, P = 0.001; HR 1.63 [95%CI 1.34-1.99] for group III, P < 0.001) and overall survival(P < 0.001, reference group I; HR 1.16 [95%CI 1.05-1.28] for group II, P = 0.004; HR 1.53 [95%CI 1.26-1.87] for group III, P < 0.001). The cumulative 5-year recurrence rates was higher in group III patients (7.4%), compared with 5.2% in group I and 5.5% in group II (P = 0.037). However, this was not significant in the competing regression analysis. CONCLUSIONS: Low pre-transplant KPS score is associated with inferior long-term survival in liver transplant HCC patients, but is not significantly associated with post-transplant tumor recurrence.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Transplante de Fígado , Adulto , Humanos , Carcinoma Hepatocelular/patologia , Neoplasias Hepáticas/patologia , Avaliação de Estado de Karnofsky , Estudos Retrospectivos , Recidiva Local de Neoplasia , Prognóstico , Listas de Espera
2.
Mikrochim Acta ; 191(5): 271, 2024 04 17.
Artigo em Inglês | MEDLINE | ID: mdl-38632191

RESUMO

Pathogen infections including Shigella flexneri have posed a significant threat to human health for numerous years. Although culturing and qPCR were the gold standards for pathogen detection, time-consuming and instrument-dependent restrict their application in rapid diagnosis and economically less-developed regions. Thus, it is urgently needed to develop rapid, simple, sensitive, accurate, and low-cost detection methods for pathogen detection. In this study, an immunomagnetic beads-recombinase polymerase amplification-CRISPR/Cas12a (IMB-RPA-CRISPR/Cas12a) method was built based on a cascaded signal amplification strategy for ultra-specific, ultra-sensitive, and visual detection of S. flexneri in the laboratory. Firstly, S. flexneri was specifically captured and enriched by IMB (Shigella antibody-coated magnetic beads), and the genomic DNA was released and used as the template in the RPA reaction. Then, the RPA products were mixed with the pre-loaded CRISPR/Cas12a for fluorescence visualization. The results were observed by naked eyes under LED blue light, with a sensitivity of 5 CFU/mL in a time of 70 min. With no specialized equipment or complicated technical requirements, the IMB-RPA-CRISPR/Cas12a diagnostic method can be used for visual, rapid, and simple detection of S. flexneri and can be easily adapted to monitoring other pathogens.


Assuntos
Anticorpos , Shigella flexneri , Humanos , Luz Azul , Fluorescência , Recombinases
3.
Am J Respir Cell Mol Biol ; 66(5): 510-523, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35213290

RESUMO

m6A (N6-methyladenosine) is the most common type of RNA methylation modification, mainly occurring on mRNA. Whether m6A-modified circular RNAs (circRNAs) are involved in pulmonary fibrosis in different settings remains unclear. Using an m6A-circRNA epitranscriptomic chip, candidate circRNAs were selected, among which hsa_circ_0000672 and hsa_circ_0005654 were specifically involved in SiO2-induced pulmonary fibrosis by targeting the same protein, eIF4A3, indicating that the m6A modification of these two circRNAs has a synergistic effect on fibroblast dysfunction induced by SiO2. A mechanistic study revealed that the m6A modification of circRNAs was mainly mediated by the methyltransferase METTL3. Furthermore, METTL3 promoted the activation, migration, and activity of pulmonary fibroblasts and participated in SiO2-induced pulmonary fibrosis via the circRNA m6A modification. m6A methylation of circRNAs mediates silica-induced fibrosis, enriching the understanding of circRNAs and uncovering a potential new target for treating fibrosis-related diseases.


Assuntos
Fibrose Pulmonar , RNA Circular , Adenosina/metabolismo , Humanos , Metilação , Metiltransferases/genética , Metiltransferases/metabolismo , Fibrose Pulmonar/induzido quimicamente , Fibrose Pulmonar/genética , RNA Circular/genética , Dióxido de Silício
4.
Ecotoxicol Environ Saf ; 169: 529-538, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30476815

RESUMO

Benzo(α)pyrene (BaP) and lead (Pb) are common pollutants discharged greatly in ocean and causing detrimental impacts on marine organisms. Although mussels are one of the most prominent and frequently studied biological models, the research on their genomic alterations induced by the mixture of two totally different chemicals, is still rare. In present study, local marine mussels Mytilus coruscus were exposed in vivo to BaP (53.74 ±â€¯19.79 µg/L), Pb (2.58 ±â€¯0.11 mg/L) and their mixture for 6 days. The genotoxic damages were assessed by comet assay, micronucleus (MNi) test, and random amplified polymorphic DNA (RAPD) analysis. Significantly increased though transitory genomic damage was investigated after the exposure and showed consistency using various detecting methods. Additive genotoxicity was only found after 3 days combined exposure by means of MNi test, suggesting that BaP and Pb may play with alternative biological targets during metabolism and/or interaction with the genome. The geno-stability and the recovery capability were further detected both in vivo and in vitro after challenged by BaP. RAPD results showed coherence in BaP induced genotoxicity, together with time-specific alterations. The genomic instability was found to recover in both in vivo and in vitro exposure scenarios in present study. To our knowledge, this is the first study to focus on the genotoxicitiy induced by BaP, Pb and their mixture by multiple detecting techniques. The attempt to utilize model pollutants and marine organism to validate the potential value of RAPD analysis highlighted that it might be a useful tool in the research of genotoxicology, especially on the effect-mechanism interplay at genetic level.


Assuntos
Benzo(a)pireno/toxicidade , Dano ao DNA , Chumbo/toxicidade , Mutagênicos/toxicidade , Mytilus/efeitos dos fármacos , Animais , Ensaio Cometa , Brânquias/química , Brânquias/efeitos dos fármacos , Técnicas In Vitro , Mytilus/genética , Técnica de Amplificação ao Acaso de DNA Polimórfico , Reprodutibilidade dos Testes
5.
J Cell Biochem ; 119(10): 7982-7990, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-29323734

RESUMO

The study was aimed to explore the functions of circulating fibrocytes (CFs) on injury repair in acute lung injury/acute respiratory distress syndrome (ALI/ARDS) mice model and its clinical value as a biomarker for ALI/ARDS. ALI/ARDS mice model was established by intratracheal instillation of lipopolysaccharide (LPS). Mononuclear cells were isolated from peripheral blood of ALI/ARDS model and flow cytometry was used to measure CFs defined as cells positive for CD45 and collagen-1. Histological changes of lung tissues were evaluated by H&E staining and Masson's trichrome staining. The correlations of CFs counts with damnification of lung tissue and the severity of pulmonary fibrosis were evaluated by Pearson correlation analyses. Western blot was used to detect the protein expression of collagen-1. ELISA was applied to determine cytokine CXCL12 concentration. Clinical relevance between CFs and ALI/ARDS was investigated. The greater number of CFs in the ALI/ARDS group implied higher degree of lung injury and more severe pulmonary fibrosis. The protein expression of collagen-1 and concentration of cytokine CXCL12 in ALI/ARDS group were higher than that in control group. Clinical and prognostic analysis revealed the higher injury degree and death rates in ALI/ARDS group than those in control group, and identified a greater severity and mortality for patients with ARDS than those with ALI. ROC curve analysis indicated the counts of CFs greater than 5.85% can predict death rates with AUC = 0.928. CFs had an inhibitory effect on injury repair in ALI/ARDS mice model. This might be unfavorable as a clinical marker for progression of ALI/ARDS.


Assuntos
Lesão Pulmonar Aguda/patologia , Síndrome do Desconforto Respiratório/metabolismo , Síndrome do Desconforto Respiratório/patologia , Lesão Pulmonar Aguda/metabolismo , Idoso , Idoso de 80 Anos ou mais , Animais , Western Blotting , Células Cultivadas , Quimiocina CXCL12/metabolismo , Colágeno/metabolismo , Modelos Animais de Doenças , Humanos , Lipopolissacarídeos/farmacologia , Masculino , Camundongos , Pessoa de Meia-Idade , Cicatrização/efeitos dos fármacos
6.
Small ; 14(50): e1803576, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30326178

RESUMO

To improve the efficiency of water electrolysis, developing efficient oxygen evolution reaction (OER) electrocatalysis is extremely important due to its four-electron transfer dynamics. In this work, a π-conjugated molecule (2,3,6,7,10,11-hexahydroxytriphenylene, HHTP), which can accelerate the electron transfer, is coated directly on pristine ZIF-67, resulting in a composite named HHTP@ZIF-67, via a simple one-step solvothermal method. The obtained HHTP@ZIF-67 possesses a Brunauer-Emmett-Teller surface area of 2013.9 m2 g-1 and displays microporous behavior, which can provide enough active sites for OER. The double-layer capacitance of HHTP@ZIF-67 is also enhanced, corresponding to an enlarged electrochemical active surface area. HHTP@ZIF-67 presents a quite low overpotential of 238 mV at 10 mA cm-2 in 1.0 m KOH. This material synthesized via the simple coating strategy is promising in the application of energy conversion devices.

7.
Chirality ; 30(12): 1245-1256, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30238493

RESUMO

Mandelic acid and its derivatives are important chiral analogs which are widely used in the pharmaceutical synthetic industry. The present study investigated the enantiomeric separation of six mandelic acids (mandelic acid, 2-chloromandelic acid, 3-chloromandelic acid, 4-chloromandelic acid, 4-bromomandelic acid, 4-methoxymandelic acid) on the Chiralpak AD-3 column by supercritical fluid chromatography. The influences of volume fraction of trifluoroacetic acid, type and percentage of modifier, column temperature, and backpressure on the separation efficiency were investigated. And the enantiomer elution order was determined. The results show that, for a given modifier, the retention factor, the separation factor, and the separation resolution decreased gradually with increasing the volume ratio of the modifier. At the same volume ratio of modifier, the retention factor of the mandelic acid and its derivatives increased in the order of methanol, ethanol, and isopropanol, except 3-chloromandelic acid. The separation factor and the separation resolution decreased with the increase of column temperature (below the temperature limit). The backpressure affected the enantioseparation process: As the backpressure increased, a corresponding decrease in retention factor was observed. Under the same chiral column conditions, the SFC method exhibited faster and more efficient separation with better enantioselectivity than the HPLC method.

8.
Cell Physiol Biochem ; 44(4): 1526-1536, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29197869

RESUMO

BACKGROUND/AIMS: Acute lung injury (ALI) remains a severe disease that threatens human life around the world. To decrease the mortality of ALI and improve ALI treatment efficacy, the development of more ALI treatments is urgently needed. Whether fibrocytes directly participate in ALI has not been studied. Therefore, a mouse model of ALI was induced with lipopolysaccharide (LPS). METHODS: Fibrocytes were harvested from peripheral blood mononuclear cells of bleomycin mice and identified by using flow cytometry to detect the expression of molecular makers. The fibrocytes were injected for the treatment of acute lung injury mice. The curative effects were evaluated by using ELISA to determine the cytokines (including TNF-α, IL-6 and IFN-γ) concentrations in bronchoalveolar lavage fluid (BALF) supernatant. RESULTS: The concentrations of cytokines such as tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interferon-γ (IFN-γ) were increased in mice with ALI induced with LPS. The concentrations of TNF-α, IL-6, and IFN-γ as well as their mRNA and protein expression levels were decreased by administration of fibrocytes. The effect of fibrocytes in ameliorating ALI was time dependent. LPS treatment induced an increase in myeloperoxidase (MPO) activity, whereas the fibrocyte treatment caused inhibition of MPO activity as well as expression of the neutrophil-chemoattractant chemokine macrophage inflammatory protein 2 (MIP-2). CONCLUSION: Taken together, these data suggest that fibrocytes ameliorated ALI by suppressing inflammatory cytokines and chemokines as well as by decreasing the accumulation of neutrophils in the lung.


Assuntos
Lesão Pulmonar Aguda/patologia , Quimiocinas/metabolismo , Citocinas/metabolismo , Fibroblastos/metabolismo , Neutrófilos/fisiologia , Lesão Pulmonar Aguda/etiologia , Animais , Bleomicina/farmacologia , Líquido da Lavagem Broncoalveolar/química , Líquido da Lavagem Broncoalveolar/citologia , Células Cultivadas , Quimiocinas/genética , Citocinas/genética , Modelos Animais de Doenças , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Leucócitos Mononucleares/citologia , Leucócitos Mononucleares/efeitos dos fármacos , Lipopolissacarídeos/toxicidade , Pulmão/imunologia , Pulmão/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Neutrófilos/imunologia , Peroxidase/metabolismo
9.
Int J Biol Macromol ; 273(Pt 2): 132971, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38880442

RESUMO

The salt-responsiveness of Pickering emulsions has significantly influenced their applications due to the large amount of salt on the surface of plant leaves. The present study provided a maleic anhydride-functionalized cellulose nanocrystal-stabilized high internal phase Pickering emulsion (MACNCs-HIPPEs) that was stable to high-concentration salt and used for pesticide delivery. The stability of MACNCs-HIPPEs was investigated by adjusting the oil-phase volume fraction (φ), the MACNCs concentration, NaCl dosages, and the rheological properties. The high internal phase Pickering emulsion was obtained at φ of 0.8 and MACNCs concentration of 2wt% and showed excellent salt stability (NaCl, 1200 mM) and significant storage stability (60 days). The sustained release of imidacloprid (IMI) from imidacloprid-loaded MACNCs-HIPPEs (IMI@MACNCs-HIPPEs) showed a positive correlation to the temperature (15°C, 25°C, 35°C), indicating clear thermo-responsiveness of the prepared pesticide formulation. The test of spread and retention of IMI@MACNCs-HIPPEs on the leaf surface showed a significant advantage compared with the commercial IMI water dispersible granules (CG). All the advantages mentioned above showed the excellent potential of the MACNCs-HIPPEs in delivering lipophilic pesticides.


Assuntos
Celulose , Emulsões , Anidridos Maleicos , Nanopartículas , Neonicotinoides , Praguicidas , Celulose/química , Nanopartículas/química , Anidridos Maleicos/química , Emulsões/química , Praguicidas/química , Neonicotinoides/química , Nitrocompostos/química , Temperatura , Liberação Controlada de Fármacos
10.
Mar Environ Res ; 199: 106610, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38879901

RESUMO

Deep-sea mussels, one of the dominant species in most deep-sea ecosystems, have long been used as model organisms to investigate the adaptations and symbiotic relationships of deep-sea macrofauna under laboratory conditions due to their ability to survive under atmospheric pressure. However, the impact of additional abiotic conditions beyond pressure, such as temperature and light, on their physiological characteristics remains unknown. In this study, deep-sea mussels (Gigantidas platifrons) from cold seep of the South China Sea, along with nearshore mussels (Mytilus coruscus) from the East China Sea, were reared in unfavorable abiotic conditions for up to 8 days. Integrated biochemical indexes including antioxidant defense, immune ability and energy metabolism were investigated in the gill and digestive gland, while cytotoxicity was determined in hemocytes of both types of mussels. The results revealed mild bio-responses in two types of mussels in the laboratory, represented by the effective antioxidant defense with constant total antioxidant capability level and malondialdehyde content. There were also disparate adaptations in deep-sea and nearshore mussels. In deep-sea mussels, significantly increased immune response and energy reservation were observed in gills, together with the elevated cytotoxicity in hemocytes, implying the more severe biological adaptation was required, mainly due to the symbiotic bacteria loss under laboratory conditions. On the contrary, insignificant biological responses were exhibited in nearshore mussels except for the increased energy consumption, indicating the trade-off strategy to use more energy to deal with potential stress. Overall, this comparative study highlights the basal bio-responses of deep-sea and nearshore mussels out of their native environments, providing evidence that short-term culture of both mussels under easily achievable laboratory conditions would not dramatically alter their biological status. This finding will assist in broadening the application of deep-sea mussels as model organism in future research regardless of the specialized research equipment.


Assuntos
Bivalves , Animais , Bivalves/fisiologia , Adaptação Fisiológica , Brânquias/metabolismo , Antioxidantes/metabolismo , Metabolismo Energético , China , Ecossistema , Mytilus/fisiologia
11.
Transl Oncol ; 45: 101987, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38743986

RESUMO

BACKGROUND: Bevacizumab resistance poses barriers to targeted therapy in clear cell renal cell carcinoma (ccRCC). Whether there exist epigenetic targets that modulate bevacizumab sensitivity in ccRCC remains indefinite. The focus of this study is to explore the role of UCHL1 in ccRCC. METHODS: Both in vitro and in vivo experiments were utilized to investigate the roles of UCHL1 in ccRCC. In vivo ubiquitination assays were performed to validate the posttranslational modification of KDM4B by UCHL1. Luciferase reporter and chromatin immunoprecipitation (ChIP) assays were utilized to explore KDM4B/VEGFA epigenetic regulations. RESULTS: UCHL1 was increased in ccRCC and associated with unfavorable survival outcomes in patients. UCHL1 was required for ccRCC growth and migration. Mechanistically, the wild-type UCHL1, but not C90A mutant, mediated the deubiquitination of KDM4B and thereby stabilized its proteins. KDM4B was up-regulated in ccRCC and potentiated cell growth. UCHL1 depended on KDM4B to augment ccRCC malignancies. Targeting UCHL1 suppressed tumor growth, colony formation, and migration abilities, which could be rescued by KDM4B. Furthermore, KDM4B was directly bound to the promoter region of VEGFA, abolishing repressive H3K9me3 modifications. KDM4B coordinated with HIF2α to activate VEGFA transcriptional levels. UCHL1-KDM4B axis governs VEGFA levels to sustain the angiogenesis phenotypes. Finally, a specific small-molecule inhibitor (6RK73) targeting UCHL1 remarkably inhibited ccRCC progression and further sensitized ccRCC to bevacizumab treatment. CONCLUSION: Overall, this study defined an epigenetic mechanism of UCHL1/KDM4B in activating VEGF signaling. The UCHL1-KDM4B axis represents a novel target for treating ccRCC and improving the efficacy of anti-angiogenesis therapy.

12.
Gut Liver ; 2024 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-38904075

RESUMO

Background/Aims: Liver transplantation is the most effective treatment for the sickest patients with acute-on-chronic liver failure (ACLF). However, the influence of donor age on liver transplantation, especially in ACLF patients, is still unclear. Methods: In this study, we used the data of the Scientific Registry of Transplant Recipients. We included patients with ACLF who received liver transplantation from January 1, 2007, to December 31, 2017, and the total number was 13,857. We allocated the ACLF recipients by age into group I (donor age ≤17 years, n=647); group II (donor age 18-59 years, n=11,423); and group III (donor age ≥60 years, n=1,787). Overall survival (OS), graft survival, and mortality were compared among the three age groups and the four ACLF grades. Cox regression was also analyzed. Results: The 1-, 3-, and 5-year OS rates were 89.6%, 85.5%, and 82.0% in group I; 89.4%, 83.4%, and 78.2% in group II; and 86.8%, 78.4%, and 71.4% in group III, respectively (p<0.001). When we analyzed the different effects of donor age on OS with different ACLF grades, in groups II and III, we observed statistical differences. Finally, the cubic spline curve told us that the relative death rate changed linearly with increasing donor age. Conclusions: Donor age is related to OS and graft survival of ACLF patients after transplantation, and poorer results were associated with elderly donors. In addition, different donor ages have different effects on recipients with different ACLF grades.

13.
J Hepatocell Carcinoma ; 11: 747-766, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38680213

RESUMO

Purpose: Nonsense-mediated RNA decay (NMD), a surveillance pathway for selective degradation of aberrant mRNAs, is associated with cancer progression. Its potential as a predictor for aggressive hepatocellular carcinoma (HCC) is unclear. Here, we present an innovative NMD risk model for predicting HCC prognosis. Methods: The Cancer Genome Atlas (TCGA) data of 374 liver HCC (LIHC) and 50 normal liver samples were extracted. A risk model based on NMD-related genes was developed through least absolute shrinkage and selection operator Cox (LASSO-Cox) regression of the LIHC-TCGA data. Prognostic validation was done using GSE54236, GSE116174, and GSE76427 data. Univariate and multivariate Cox regression analyses were conducted to assess the prognostic value of the model. We also constructed nomograms for survival prediction. Tumor immune infiltration was evaluated using the CIBERSORT algorithm, and the tumor cell phenotype was assessed. Finally, mouse experiments verified UPF3B knockdown effects on HCC tumor characteristics. Results: We developed a risk model based on four NMD-related genes (PABPC1, RPL8, SMG5, and UPF3B) and validated it using GSE54236, GSE116174, and GSE76427 data. The model effectively distinguished high- and low-risk groups corresponding to unfavorable and favorable HCC outcomes. Its prognostic prediction accuracy was confirmed through time-dependent ROC analysis, and clinical-use nomograms with calibration curves were developed. Single-cell RNA sequencing results indicated significantly higher expression of SMG5 and UPF3B in tumor cells. Knockdown of SMG5 and UPF3B inhibited HCC cell proliferation, invasion, and migration, while affecting cell-cycle progression and apoptosis. In vivo, UPF3B knockdown delayed tumor growth and increased immune cell infiltration. Conclusion: Our NMD-related gene-based risk model can help identify therapeutic targets and biomarkers for HCC. Additionally, it assists clinicians in predicting the prognosis of HCC patients.

14.
Nat Commun ; 14(1): 3864, 2023 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-37391417

RESUMO

The eukaryotic single-stranded DNA (ssDNA)-binding protein Replication Protein A (RPA) plays a crucial role in various DNA metabolic pathways, including DNA replication and repair, by dynamically associating with ssDNA. While the binding of a single RPA molecule to ssDNA has been thoroughly studied, the accessibility of ssDNA is largely governed by the bimolecular behavior of RPA, the biophysical nature of which remains unclear. In this study, we develop a three-step low-complexity ssDNA Curtains method, which, when combined with biochemical assays and a Markov chain model in non-equilibrium physics, allow us to decipher the dynamics of multiple RPA binding to long ssDNA. Interestingly, our results suggest that Rad52, the mediator protein, can modulate the ssDNA accessibility of Rad51, which is nucleated on RPA coated ssDNA through dynamic ssDNA exposure between neighboring RPA molecules. We find that this process is controlled by the shifting between the protection mode and action mode of RPA ssDNA binding, where tighter RPA spacing and lower ssDNA accessibility are favored under RPA protection mode, which can be facilitated by the Rfa2 WH domain and inhibited by Rad52 RPA interaction.


Assuntos
DNA de Cadeia Simples , Rad51 Recombinase , Proteína de Replicação A , DNA de Cadeia Simples/genética , Proteínas de Ligação a DNA/genética , Proteína de Replicação A/genética , Rad51 Recombinase/genética
15.
Micromachines (Basel) ; 15(1)2023 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-38258211

RESUMO

A 6500 V SiC trench MOSFET with integrated unipolar diode (UD-MOS) is proposed to improve reverse conduction characteristics, suppress bipolar degradation, and reduce switching loss. An N type base region under the trench dummy gate provides a low barrier path to suppress hole injection during the reverse conduction operation. The reverse conduction voltage VON is reduced to 1.11 V, and the reverse recovery charge (QRR) is reduced to 1.22 µC/cm2. The gate-to-drain capacitance (CGD) and gate-to-source capacitance (CGS) of the UD-MOS are also reduced to improve switching loss due to the thick oxide layer between the trench gate and dummy gate. The proposed device exhibits an excellent loss-related figure of merit (FOM). It provides a high-voltage SiC MOSFET prototype with potential performance advantages for voltage source converter-based high voltage direct current applications.

16.
Expert Rev Gastroenterol Hepatol ; 17(2): 215-223, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36688344

RESUMO

BACKGROUND: NASH-related liver transplants are increasing because of the obesity epidemic, but the influence of T2DM on various levels of BMI among NASH recipients is unclear. RESEARCH DESIGN AND METHODS: We analyzed data retrieved from SRTR on 4,515 patients. We divided patients by BMI into five groups: normal weight; overweight; class 1 obesity; class 2 obesity; and class 3 obesity. Statistical analysis was done. RESULTS: Patients in the NASH group with T2DM had a lower patient and graft survival than patients without T2DM (5-year patient and graft survival: 77.5% vs. 79.8%; P = 0.001 and 76.4% vs. 78.2%; P = 0.002, respectively). Multivariate Cox proportional regression showed an independent association between T2DM and decreased patient and graft survival (HR, 1.170; P = 0.015 and HR, 1.133; P = 0.048, respectively). In the lean and the class 3 obesity NASH groups, patients with T2DM had lower patient and graft survival than the patients without T2DM. In the class 3 obesity NASH group, T2DM was independently associated with decreased patient survival (HR, 1.581; P = 0.027). CONCLUSION: Our research reveals that the focus of the post-transplantation treatment should be different for different BMI patients.


Assuntos
Diabetes Mellitus Tipo 2 , Transplante de Fígado , Hepatopatia Gordurosa não Alcoólica , Humanos , Hepatopatia Gordurosa não Alcoólica/diagnóstico , Hepatopatia Gordurosa não Alcoólica/epidemiologia , Hepatopatia Gordurosa não Alcoólica/cirurgia , Transplante de Fígado/efeitos adversos , Índice de Massa Corporal , Obesidade/complicações , Obesidade/diagnóstico , Obesidade/epidemiologia , Diabetes Mellitus Tipo 2/complicações , Estudos Retrospectivos , Fatores de Risco
17.
J Hazard Mater ; 452: 131350, 2023 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-37030223

RESUMO

Polychlorinated biphenyls (PCBs) and microplastics (MPs) commonly co-exist in various environments. MPs inevitably start aging once they enter environment. In this study, the effect of photo-aged polystyrene MPs on microbial PCB dechlorination was investigated. After a UV aging treatment, the proportion of oxygen-containing groups in MPs increased. Photo-aging promoted the inhibitory effect of MPs on microbial reductive dechlorination of PCBs, mainly attributed to the inhibition of meta-chlorine removal. The inhibitory effects on hydrogenase and adenosine triphosphatase activity by MPs increased with increasing aging degree, which may be attributed to electron transfer chain inhibition. PERMANOVA showed significant differences in microbial community structure between culturing systems with and without MPs (p < 0.05). Co-occurrence network showed a simpler structure and higher proportion of negative correlation in the presence of MPs, especially for biofilms, resulting in increased potential for competition among bacteria. MP addition altered microbial community diversity, structure, interactions, and assembly processes, which was more deterministic in biofilms than in suspension cultures, especially regarding the bins of Dehalococcoides. This study sheds light on the microbial reductive dechlorination metabolisms and mechanisms where PCBs and MPs co-exist and provides theoretical guidance for in situ application of PCB bioremediation technology.


Assuntos
Bifenilos Policlorados , Envelhecimento da Pele , Bifenilos Policlorados/metabolismo , Microplásticos , Plásticos , Poliestirenos , Biodegradação Ambiental , Cloro/farmacologia , Cloro/metabolismo , Sedimentos Geológicos/microbiologia
18.
Biophys Rep ; 8(2): 80-89, 2022 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-37287827

RESUMO

Many recent references show that living cells can form some membrane-less organelles by liquid-liquid phase separation (LLPS) of biomolecules, like proteins and nucleic acids. LLPS has been confirmed to link with many important biological functions in living cells, and one of the most important functions of biomolecular condensates is in the field of RNA transcription. Many studies confirm that mammalian RNA polymerase II (Pol II) molecules containing the CTD with different phosphorylation level are purposed to shuttle between initiation condensates and elongation condensates of RNA transcription. Traditional ensemble assays often experience difficulties in quantitively and directly recording the transient recruitment of Pol II CTD. Novel single-molecule approach - DNA curtains can be used to directly visualize biomolecular condensates formation and also recruitment of RNA polymerase II (Pol II) carboxyl-terminal domain (CTD) at the target sites in solution and in real time. This method can offer the potential for new insights into the mechanism of gene transcription. Here, we highlight the detailed protocol of DNA curtains method for studying LLPS.

19.
J Colloid Interface Sci ; 617: 620-632, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35305474

RESUMO

Yolk-shell structure materials with the light weight, excellent impedance matching and electromagnetic wave (EMW) loss ability were widely used in the field of absorbing materials. However, the previous researches on this kind of structure always focused on the comparison between solid structure and empty structure. Different from previous studies, in this paper, the effect of yolk-shell structure with different air layer thickness on EMW absorption was studied for the first time. Graphene oxide (GO) supported yolk-shell ZnS/Ni3S4 absorbers with adjustable air layer were prepared by a simple two-step hydrothermal method. Through the equivalence of RLC resonant circuit and the elimination of the influence of polarization relaxation and conduction loss, it was found that yolk-shell structure with different air layer thickness will resonate with EMW of different frequencies, thus increasing the loss capacity of materials to EMW of this frequency. At the same time, Compared with the solid structure, the yolk-shell structure can not only make the material lighter, but also cause multiple reflections and scattering of EMW. Noteworthy, yolk-shell structure composite material exhibits the maximum reflection loss (RL) of -63.0 dB at 4.8 GHz and an effective absorption bandwidth (EAB) of 4.1 GHz at a thickness of 1.6 mm. This research provides an idea and basis for the design of absorbing materials that respond to different frequency EMW.

20.
J Colloid Interface Sci ; 607(Pt 2): 1287-1299, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34583034

RESUMO

High-performance electromagnetic (EM) absorbers are necessary for military and industry application in view of the extensive utilization of EM devices. Carbon fibers (CFs) have been considered as promising candidates in electromagnetic wave (EMW) absorption materials, while the single carbon fiber material cannot achieve satisfactory EMW absorption performance because of its limited impedance matching. Herein, electrodeposition and hydrothermal methods were used to fabricate vertical hollow ZnS nanoarrays on carbon cloth (CC) substrate, and then one kind of novel flexible EM composite absorbers with excellent performance was obtained through adjusting morphology of hollow ZnS nanoarrays by easily changing the synthesis parameters of the precursor. Noteworthy, the miniaturized cone-shaped hollow ZnS nanoarray composite absorber shows excellent EMW absorption performance of strong absorption and wide absorption band. The maximum reflection loss value is -52.5 dB and the effective absorption bandwidth reaches 5.1 GHz when the thickness is only 1.9 mm. At the same time, the composite possesses the characteristics of light weight and thin thickness. The excellent properties of the composite absorbers are mainly attributed to their morphological structure. The unique hollow ZnS nanoarray structure enhances the interface polarization and multiple reflections, meanwhile also giving it the properties of metamaterials with resonant absorption. Furthermore, the adjustment of the ZnS nanoarray morphology can not only change the transmission behavior of EMW but also affect the resonance frequency and intensity of the ZnS nanoarray unit. This study obtains high-performance absorbing materials with flexible characteristics as well as highlights the importance of the adjustment of the morphological structure to improve the EMW absorption performance.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA