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1.
Cell Mol Biol Lett ; 29(1): 55, 2024 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-38643118

RESUMO

BACKGROUND: Viral myocarditis (VMC) is a disease resulting from viral infection, which manifests as inflammation of myocardial cells. Until now, the treatment of VMC is still a great challenge for clinicians. Increasing studies indicate the participation of miR-29b-3p in various diseases. According to the transcriptome sequencing analysis, miR-29b-3p was markedly upregulated in the viral myocarditis model. The purpose of this study was to investigate the role of miR-29b-3p in the progression of VMC. METHODS: We used CVB3 to induce primary cardiomyocytes and mice to establish a model of viral myocarditis. The purity of primary cardiomyocytes was identified by immunofluorescence. The cardiac function of mice was detected by Vevo770 imaging system. The area of inflammatory infiltration in heart tissue was shown by hematoxylin and eosin (H&E) staining. The expression of miR-29b-3p and DNMT3A was detected by quantitative real time polymerase chain reaction (qRT-PCR). The expression of a series of pyroptosis-related proteins was detected by western blot. The role of miR-29b-3p/DNMT3A in CVB3-induced pyroptosis of cardiomyocytes was studied in this research. RESULTS: Our data showed that the expression of miR-29b-3p was upregulated in CVB3-induced cardiomyocytes and heart tissues in mice. To explore the function of miR-29b-3p in CVB3-induced VMC, we conducted in vivo experiments by knocking down the expression of miR-29b-3p using antagomir. We then assessed the effects on mice body weight, histopathology changes, myocardial function, and cell pyroptosis in heart tissues. Additionally, we performed gain/loss-of-function experiments in vitro to measure the levels of pyroptosis in primary cardiomyocytes. Through bioinformatic analysis, we identified DNA methyltransferases 3A (DNMT3A) as a potential target gene of miR-29b-3p. Furthermore, we found that the expression of DNMT3A can be modulated by miR-29b-3p during CVB3 infection. CONCLUSIONS: Our results demonstrate a correlation between the expression of DNMT3A and CVB3-induced pyroptosis in cardiomyocytes. These findings unveil a previously unidentified mechanism by which CVB3 induces cardiac injury through the regulation of miR-29b-3p/DNMT3A-mediated pyroptosis.


Assuntos
MicroRNAs , Miocardite , Camundongos , Animais , Miocardite/genética , Miocardite/metabolismo , Miócitos Cardíacos/metabolismo , Piroptose , MicroRNAs/genética , MicroRNAs/metabolismo , Inflamação/metabolismo , Antagomirs/metabolismo
2.
Org Lett ; 2024 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-38651729

RESUMO

The direct functionalization of methylene C(sp3)-H bonds is one of the greatest challenges in transition metal-catalyzed C-H activation. Although Pd(0)-catalyzed intramolecular cyclization reactions of methylene C(sp3)-H bonds have been reported, intermolecular functionalization remains to be discovered. Herein, we report the first example of a Pd(0)-catalyzed intermolecular methylene C(sp3)-H functionalization reaction. By use of a N-heterocyclic carbene ligand, the methylene C(sp3)-H bonds of 1-(benzyloxy)-2-iodobenzenes are activated and disilylated with hexamethyldisilane, affording disilylated products.

3.
Eur J Surg Oncol ; 50(6): 108336, 2024 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-38626589

RESUMO

INTRODUCTION: There has been a lack of research comparing the efficacy of various treatments for low anterior resection syndrome (LARS). METHODS: We conducted a comprehensive search across six electronic databases and a paired meta-analysis was undertaken to assess the effectiveness of the interventions. Furthermore, a network meta-analysis was utilized to compare the efficacy of different treatments for LARS. RESULTS: This study encompassed nine randomized controlled trials, involving a total of 450 patients. Compared to routine care, 5-HT3 receptor antagonists (follow-up<3 months) and percutaneous tibial nerve stimulation (3 months ≤ follow-up <6 months) were effective in reducing the LARS score. Pelvic floor rehabilitation (follow-up≤3 months) was effective in decreasing daily number of bowel movements when compared to routine care. The network meta-analysis indicated that 5-HT3 receptor antagonists (follow-up<3 months) were the most effective in reducing both the LARS score and the daily number of bowel movements. Transanal irrigation (3 months ≤ follow-up ≤ 12 months) was most effective in reducing the LARS score. Additionally, 5-HT3 receptor antagonists demonstrated relative efficacy in improving patients' quality of life (follow-up ≤ 1 month). CONCLUSIONS: This review indicates that 5-HT3 receptor antagonists and anal irrigation show significant promise in the treatment of LARS. Nevertheless, the contributions of percutaneous tibial nerve stimulation and pelvic floor rehabilitation to LARS treatment should not be overlooked. Given the clinical heterogeneity observed among the studies, the results should be interpreted with caution.

4.
J Clin Nurs ; 2024 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-38528346

RESUMO

AIMS: This study aimed to explore the psychosocial adjustment of enterostomy patients on a national scale. DESIGN: Based on a national cross-sectional survey. METHODS: From December 2021 and February 2023, a total of 22,040 enterostomy patients were assessed using the ostomy adjustment inventory-20. Initial analysis involved employing the chi-square test or Kruskal-Wallis H test to identify factors influencing the psychosocial adjustment of these patients. Subsequently, multinomial logistic regression was used to determine the factors affecting the classification of psychosocial adjustment levels of enterostomy patients. The reporting of this study adhered to the STROBE checklist. RESULTS: Eventually 21,124 patients with enterostomy were included in this study, out of which 7788 (36.9%) patients with low level of psychosocial adjustment, 11,803 (55.8%) patients with medium level of psychosocial adjustment and 1533 (7.3%) patients with high level of psychosocial adjustment. The factors influencing the classification of psychosocial adjustment levels of enterostomy patients were gender, educational background, carer, enterostomy self-care knowledge score and medical payment method. CONCLUSIONS: The overall psychosocial adjustment level of enterostomy patients is not optimistic, and the factors that may affect the classification of their psychosocial adjustment level are analysed. Individualised intervention should be given according to different psychosocial adjustment levels of enterostomy patients. RELEVANCE TO CLINICAL PRACTICE: The number of enterostomy patients with a high level of psychosocial adjustment is small in relation to the total number of enterostomy patients, and caregivers can provide health education to enterostomy patients by analysing the factors affecting the level of psychosocial adjustment of enterostomy patients. PATIENT OR PUBLIC CONTRIBUTION: None.

5.
Int J Mol Sci ; 25(5)2024 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-38473909

RESUMO

Mutations of the FBN1 gene lead to Marfan syndrome (MFS), which is an autosomal dominant connective tissue disorder featured by thoracic aortic aneurysm risk. There is currently no effective treatment for MFS. Here, we studied the role of mitochondrial dysfunction in the phenotypic transformation of human smooth muscle cells (SMCs) and whether a mitochondrial boosting strategy can be a potential treatment. We knocked down FBN1 in SMCs to create an MFS cell model and used rotenone to induce mitochondrial dysfunction. Furthermore, we incubated the shFBN1 SMCs with Coenzyme Q10 (CoQ10) to assess whether restoring mitochondrial function can reverse the phenotypic transformation. The results showed that shFBN1 SMCs had decreased TFAM (mitochondrial transcription factor A), mtDNA levels and mitochondrial mass, lost their contractile capacity and had increased synthetic phenotype markers. Inhibiting the mitochondrial function of SMCs can decrease the expression of contractile markers and increase the expression of synthetic genes. Imposing mitochondrial stress causes a double-hit effect on the TFAM level, oxidative phosphorylation and phenotypic transformation of FBN1-knockdown SMCs while restoring mitochondrial metabolism with CoQ10 can rapidly reverse the synthetic phenotype. Our results suggest that mitochondria function is a potential therapeutic target for the phenotypic transformation of SMCs in MFS.


Assuntos
Síndrome de Marfan , Doenças Mitocondriais , Ubiquinona/análogos & derivados , Humanos , Síndrome de Marfan/genética , Fenótipo , Miócitos de Músculo Liso/metabolismo , Doenças Mitocondriais/metabolismo , Fibrilina-1/metabolismo , Adipocinas/metabolismo
6.
Angew Chem Int Ed Engl ; 63(18): e202402202, 2024 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-38375743

RESUMO

Poly(ethylene oxide) (PEO)-based electrolytes are often used for Li+ conduction as they can dissociate the Li salts efficiently. However, high entanglement of the chains and lack of pathways for rapid ion diffusion limit their applications in advanced batteries. Recent developments in ionic covalent organic frameworks (iCOFs) showed that their highly ordered structures provide efficient pathways for Li+ transport, solving the limitations of traditional PEO-based electrolytes. Here, we present imidazolate COFs, PI-TMEFB-COFs, having methoxyethoxy chains, synthesized by Debus-Radziszewski multicomponent reactions and their ionized form, Li+@PI-TMEFB-COFs, showing a high Li+ conductivity of 8.81 mS cm-1 and a transference number of 0.974. The mechanism for such excellent electrochemical properties is that methoxyethoxy chains dissociate LiClO4, making free Li+, then those Li+ are transported through the imidazolate COFs' pores. The synthesized Li+@PI-TMEFB-COFs formed a stable interface with Li metal. Thus, employing Li+@PI-TMEFB-COFs as the solid electrolyte to assemble LiFePO4 batteries showed an initial discharge capacity of 119.2 mAh g-1 at 0.5 C, and 82.0 % capacity and 99.9 % Coulombic efficiency were maintained after 400 cycles. These results show that iCOFs with ether chains synthesized via multicomponent reactions can create a new chapter for making solid electrolytes for advanced rechargeable batteries.

7.
Sci Total Environ ; 922: 171216, 2024 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-38412878

RESUMO

A large portion of Central-Western Asia is made up of contiguous closed basins, collectively termed as the Asian Endorheic Basins (AEBs). As these retention basins are only being replenished by the intermittent and scarce rainfall, global warming coupled with ever-rising human demand for water is exerting unprecedented pressures on local water and ecological security. Recent studies revealed a persistent and widespread water storage decline across the AEBs, yet the response of dryland vegetation to this recent hydroclimatic trend and a spatially explicit partitioning of the impact into the hydroclimatic factors and human activities remain largely unknown. To fill in this knowledge gap, we conducted trend and partial correlation analysis of vegetation and hydroclimatic change from 2001 to 2021 using multi-satellite observations, including vegetation greenness, total water storage anomalies (TWSA) and meteorological data. Here we show that much of the AEB (65.53 %), encompassing Mongolia Plateau, Northwest China, Qinghai Tibet Plateau, and Western Asia (except the Arabian Peninsula), exhibited a significant greening trend over the past two decades. In arid AEB, precipitation dominated the vegetation productivity trend. Such a rainfall dominance gave way to TWSA dominance in the hyper-arid AEB. We further showed that the decoupling of rainfall and hyper-arid vegetation greening was largely due to a significant expansion (17.3 %) in irrigated cropland across the hyper-arid AEB. Given the extremely harsh environment in the AEB, our results therefore raised a significant concern on the ecological and societal sustainability in this region, where a mild increase in precipitation cannot catch up the rising evaporative demand and water consumption resulted from global warming and agriculture intensification.

8.
Nutrients ; 16(3)2024 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-38337710

RESUMO

Procuring food enriched with diverse nutrients is pivotal for maintaining a robust immune system. However, the food system is now unprecedentedly globalized and faces challenges arising from climate change, pandemics, and political unrest. This study aims to illuminate the gap in exploring the adequacy and distribution equity of nutrition supplies in response to potential trade fluctuations and restrictions on agrifood within China's local agriculture endowments. Also, it seeks to identify the role of trade in contributing to these indices. Accordingly, we analyzed the distribution of nutrients in agrifood categories from production to consumption and assessed the adequacy and distribution equity of corresponding available nutrition supply from the local food provision system in terms of meeting residents' nutritional requirements, across China, and compared with those in the practical market. The local self-supply system showed that 12 out of 31 provinces have difficulty achieving an iron supply with 11% to 108% deficiencies. Except for iron, 52% (folate)-90% (vitamin B12) of agricultural output was available for diet provisioning nationwide. While food trade emerges as a crucial factor in enhancing secure and equitable nutrition supply, risks associated with micronutrient deficiencies necessitate careful consideration in current global circumstances. Our analysis explored a regional pool of nutrient information in supplements to the conventional food profile in China and could implicate better knowledge toward healthier food supplies and tailored improvements for achieving a resilient nutrition supply.


Assuntos
Dieta , Estado Nutricional , Suplementos Nutricionais , Ferro , China
9.
J Chem Phys ; 159(21)2023 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-38054519

RESUMO

The demand for applications, such as coatings, separation filters, and electronic packaging, has greatly driven the research of polymer films. At nanometer scale, mechanical properties of thin polymer films can significantly deviate from bulk. Despite outstanding progresses, there still lack deep discussions on nonlinear viscoelastic-viscoplastic response and their interactions under nanoconfinement. In this work, by conducting measurements via the bubble inflation method and modelling using Schapery and Perzyna equations, we demonstrate nonlinear viscoelastic-viscoplastic properties of freely standing thin polystyrene (PS) films. The results show the unchanged glassy compliance and the rubbery stiffening phenomenon for thin PS films, where the lower rubbery plateau in rubbery stiffening may originate from the induced molecular orientation by plastic deformation. With decreasing film thickness, viscosity and yield stress in viscoplasticity increase in an exponential and a linear trend, respectively, indicating the significant role of nanoconfinement effect on viscoplastic properties. These findings may reveal that there are many properties from linear viscoelasticity to nonlinear viscoelasticity-viscoplasticity that need to be explored and unveiled for sufficient understanding of the nanoconfinement effect on altering mechanical behavior of polymers.

10.
J Am Chem Soc ; 2023 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-37916601

RESUMO

Lithium (Li)-metal batteries (LMBs) possess the highest theoretical energy density among current battery designs and thus have enormous potential for use in energy storage. However, the development of LMBs has been severely hindered by safety concerns arising from dendrite growth and unstable interphases on the Li anode. Covalent organic frameworks (COFs) incorporating either redox-active or anionic moieties on their backbones have high Li-ion (Li+) conductivities and mechanical/chemical stabilities, so are promising for solid electrolyte interphases (SEIs) in LMBs. Here, we synthesized anthraquinone-based silicate COFs (AQ-Si-COFs) that contained both redox-active and anionic sites via condensation of tetrahydroxyanthraquinone with silicon dioxide. The nine Li+-mediated charge/discharge processes enabled the AQ-Si-COF to demonstrate an ionic conductivity of 9.8 mS cm-1 at room temperature and a single-ion-conductive transference number of 0.92. Computational studies also supported the nine Li+ mechanism. We used AQ-Si-COF as the solid electrolyte interphase on the Li anode. The LMB cells with a LiCoO2 cathode attained a maximum reversible capacity of 188 mAh g-1 at 0.25 C during high-voltage operation. Moreover, this LMB cell demonstrated suppressed dendrite growth and stable cyclability, with its capacity decreasing by less than 3% up to 100 cycles. These findings demonstrate the effectiveness of our redox-active and anionic COFs and their practical utility as SEI in LMB.

11.
Small ; : e2307057, 2023 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-37972278

RESUMO

Understanding the underlying catalytic mechanisms with nanometer resolution is of critical importance to the rational design of 1D heterogeneous catalysts. However, a fundamental investigation of photocatalytic activities and kinetics at their individual sites is still challenging. Herein, in situ single-molecule fluorescence microscopy is employed to study the site-specific catalytic activities and dynamics on 1D-1D heterostructure for the first time. For carbon nanotube (CNT)/CdS nanorod composites, it is found that the CdS end with heterojunction exhibits the highest catalytic conversion rate constant of resazurin photoreduction, which is 30%, 7%, and 19% higher than those of the middle segment and the bare end of CdS, and the CNT end with heterojunction, respectively. A similar trend of adsorption abilities is observed in these structures. Such phenomena can be attributed to the different content of defects in these structures. Regarding the dissociation behaviors, the dissociation rate constants of all structures exhibit an opposite trend to those of adsorption and conversion. The direct and indirect dissociation are found to be predominant on CdS and CNT, respectively. Such investigation provides a deep insight into the understanding of site-specific properties on 1D heterogeneous catalysts and helps construct the "structure-dynamics" correlations at the nanoscale.

12.
Sci Rep ; 13(1): 16591, 2023 10 03.
Artigo em Inglês | MEDLINE | ID: mdl-37789089

RESUMO

Disruptions of key food and fertilizer exports from Russia and Ukraine have exposed many countries to challenges accessing some commodities since these countries' war began. We evaluated the short-term, external, and direct impacts of disruptions of six food commodities and three types of fertilizer supplies from Russia and Ukraine on food access for all trading partners of the two countries by applying a set of trade and socioeconomic indicators. We found that the external food supplies of 279 countries and territories were affected to varying degrees; 24 countries-especially Georgia, Armenia, Kazakhstan, Azerbaijan, and Mongolia-are extremely vulnerable because they depend almost entirely on a variety of food imports from Russia and Ukraine. Access to fertilizers was affected in 136 countries and territories, particularly Estonia (potassic fertilizer), Mongolia (nitrogenous fertilizers), Kazakhstan (mixed fertilizers), and Brazil, the United States, China, and India (all types of fertilizers). An integrated assessment of countries' import types, purchasing power parity per capita, and populations indicated that the Democratic Republic of the Congo, Ethiopia, Egypt, and Pakistan are most vulnerable to such supply disruptions. Development of research into diversification and decentralization strategies for food access is needed to guide stable food supply policies.


Assuntos
Fertilizantes , Abastecimento de Alimentos , Ucrânia , Federação Russa , República da Geórgia , Armênia
13.
Angew Chem Int Ed Engl ; 62(44): e202311082, 2023 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-37698088

RESUMO

We report an azide-functionalized cobaloxime proton-reduction catalyst covalently tethered into the Wurster-type covalent organic frameworks (COFs). The cobaloxime-modified COF photocatalysts exhibit enhanced photocatalytic activity for hydrogen evolution reaction (HER) in alcohol-containing solution with no presence of a typical sacrificial agent. The best performing cobaloxime-modified COF hybrid catalyzes hydrogen production with an average HER rate up to 38 µmol h-1 in ethanol/phosphate buffer solution under 4 h illumination. Ultrafast transient optical spectroscopy characterizations and charge carrier analysis reveal that the alcohol contents functioning as hole scavengers could be oxidized by the photogenerated holes of COFs to form aldehydes and protons. The consumption of the photogenerated holes thus suppresses exciton recombination of COFs and improves the ratio of free electrons that were effectively utilized to drive catalytic reaction for HER. This work demonstrates a great potential of COF-catalyzed HER using alcohol solvents as hole scavengers and provides an example toward realizing the accessibility to the scope of reaction conditions and a greener route for energy conversion.

14.
Acta Radiol ; 64(9): 2578-2589, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37593946

RESUMO

BACKGROUND: Accurate differentiation of nodular fasciitis (NF) from soft tissue sarcoma (STS) before surgery is essential for the subsequent diagnosis and treatment of patients. PURPOSE: To develop and evaluate radiomics nomograms based on clinical factors and magnetic resonance imaging (MRI) for the preoperative differentiation of NF from STS. MATERIAL AND METHODS: This retrospective study analyzed the MRI data of 27 patients with pathologically diagnosed NF and 58 patients with STS who were randomly divided into training (n = 62) and validation (n = 23) groups. Univariate and multivariate analyses were performed to identify the clinical factors and semantic features of MRI. Radiomics analysis was applied to fat-suppressed T1-weighted (T1W-FS) images, fat-suppressed T2-weighted (T2W-FS) images, and contrast-enhanced T1-weighted (CE-T1W) images. The radiomics nomograms incorporating the radiomics signatures, clinical factors, and semantic features of MRI were developed. ROC curves and AUCs were carried out to compare the performance of the clinical factors, radiomics signatures, and clinical radiomics nomograms. RESULTS: Tumor location, size, heterogeneous signal intensity on T2W-FS imaging, heterogeneous signal intensity on CE-T1W imaging, margin definitions on CE-T1W imaging, and septa were independent predictors for differentiating NF from STS (P < 0.05). The performance of the radiomics signatures based on T2W-FS imaging (AUC = 0.961) and CE-T1W imaging (AUC = 0.938) was better than that based on T1W-FS imaging (AUC = 0.833). The radiomics nomograms had AUCs of 0.949, which demonstrated good clinical utility and calibration. CONCLUSION: The non-invasive clinical radiomics nomograms exhibited good performance in the differentiation of NF from STS, and they have clinical application in the preoperative diagnosis of diseases.


Assuntos
Fasciite , Sarcoma , Neoplasias de Tecidos Moles , Humanos , Nomogramas , Estudos Retrospectivos , Imageamento por Ressonância Magnética , Sarcoma/diagnóstico por imagem , Neoplasias de Tecidos Moles/diagnóstico por imagem , Fasciite/diagnóstico por imagem
15.
Talanta ; 265: 124910, 2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-37418961

RESUMO

Excessive levels of cyanide (CN-) and hypochlorite (ClO-) anions are the significant threats to the human health and the environment. Thus, great efforts have been to design and synthesize molecular sensors for the simple, instantaneous and efficient detecting environmentally and biologically important anions. Currently, developing a single molecular sensor for multi-analyte sensing is still a challenging task. In our present work, we developed a new molecular sensor (3TM) based on oligothiophene and Meldrum's acid units for detecting cyanide and hypochlorite anions in biological, environmental and food samples. The detecting ability of 3TM has been examined to various testing substances containing amino acids, reactive oxygen species, cations and anions, showing its high selectivity, excellent sensitivity, short response time (ClO-: 30 s, CN-: 100 s), and broad pH working range (4-10). The detection limits were calculated as 4.2 nM for ClO- in DMSO/H2O (1/8, v/v) solution and 6.5 nM for CN- in DMSO/H2O (1/99, v/v) solution. Sensor 3TM displayed sharp turn-on fluorescence increasement (555 nm, 435 nm) and sensitive fluorescence color changes caused by CN-/ClO-, which is ascribed to the nucleophilic addition and oxidation of ethylenic linkage by cyanide and hypochlorite, respectively. Moreover, sensor 3TM was applied for hypochlorite and cyanide detecting in real-world water, food samples and bio-imaging in live cells and zebrafish. To our knowledge, the developed 3TM sensor is the seventh single-molecular sensor for simultaneous and discriminative detecting hypochlorite and cyanide in food, biological and aqueous environments using two distinct sensing modes.


Assuntos
Cianetos , Peixe-Zebra , Animais , Humanos , Cianetos/química , Ácido Hipocloroso , Dimetil Sulfóxido , Corantes Fluorescentes/química , Ânions , Água/química
16.
Chem Commun (Camb) ; 59(26): 3918-3921, 2023 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-36919710

RESUMO

We report the utilization of single-molecule fluorescence microscopy to in situ quantify the photo-oxidation reaction kinetics on g-C3N4. The wrinkle structure shows the highest reactivity and direct dissociation rate. The basal plane exhibits the highest affinity to reactants and products and indirect dissociation rate constant, followed by edges and wrinkles.

17.
Food Res Int ; 164: 112418, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36738023

RESUMO

Cronobacter sakazakii (C. sakazakii), a food-borne pathogen, can infect neonates, elderly and immunocompromised populations with a high infection and mortality rate. However, the specific molecular mechanism of its motility, biofilm formation, cell adhesion, and desiccation resistance remains unclear, and flagellum hook associated protein (FlgK), a main component of the flagellar complex, may be an important determinant of its virulence and desiccation resistance. In this study, the flgK mutant strain (ΔflgK) was constructed using the homologous recombination method, and the cpflgK complementary strain was obtained by gene complementation, followed by analysis of the difference between the wild type (WT), mutant, and complementary strains in mobility, biofilm formation, cell adhesion, and desiccation resistance. Results indicated that flgK gene played a positive role in motility and invasion, with no significant effect on biofilm formation. Interestingly, flagellar assembly gene deletion showed increased resistance of C. sakazakii to dehydration. The mechanism underlying the negative correlation of flgK gene with dehydration resistance was further investigated by using the high-throughput sequencing technology to compare the gene expression between WT and ΔflgK strains after drying. The results revealed up-regulation in the expression of 54 genes, including genes involved in osmosis and formate dehydrogenase, while down-regulation in the expression of 50 genes, including genes involved in flagellum hook and nitrate reductase. qRT-PCR analysis of the RNA-seq data further indicated that the flgK gene played an important role in the environmental stress resistance of C. sakazakii by up-regulating the formate dehydrogenase, betaine synthesis, and arginine deiminase pathways, due to dynamic proton imbalance caused by lack of flagella. This study facilitates our understanding of the roles of flgK in motion-related functions and the molecular mechanism of desiccation resistance in C. sakazakii.


Assuntos
Proteínas de Bactérias , Cronobacter sakazakii , Humanos , Recém-Nascido , Idoso , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Cronobacter sakazakii/metabolismo , Desidratação , Dessecação , Formiato Desidrogenases/metabolismo
18.
Nanoscale ; 15(7): 3449-3460, 2023 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-36722928

RESUMO

Graphitic carbon nitride (g-C3N4) has attracted extensive research attention in recent years due to its unique layered structure, facile synthetic route, visible-light-responsive nature, and excellent photocatalytic performance. However, an insightful investigation of site-specific catalytic activities and kinetics on g-C3N4 is still warranted. Here, we fabricated ultrathin g-C3N4 nanosheets through thermal exfoliation. The optimized sample exhibits a high specific surface area of 307.35 m2 g-1 and a remarkable H2 generation activity of 2008 µmol h-1 g-1 with an apparent quantum efficiency of 4.62% at λ = 420 nm. Single-molecule fluorescence microscopy was applied for the first time to spatially resolve the reaction heterogeneities with nanometer precision (∼10 nm). The catalytic kinetics (i.e., reactant adsorption, conversion, and product dissociation) and temporal activity fluctuations were in situ quantified at individual structural features (i.e., wrinkles, edges, and basal planes) of g-C3N4. It was found that the wrinkle and edge exhibited superior photocatalytic activity due to the intrinsic band modulation, which are 20 times and 14.8 times that of the basal plane, respectively. Moreover, due to the steric effect, the basal plane showed the highest adsorption constant and the lowest direct dissociation constant. Density functional theory (DFT) simulations unveiled the adsorption energies of reactant and product molecules on each structure of g-C3N4, which support our experimental results. Such investigation would shed more light on the fundamental understanding of site-specific catalytic dynamics on g-C3N4, which benefits the rational design of 2D layered materials for efficient solar-to-chemical energy conversion.

19.
Anal Chim Acta ; 1239: 340735, 2023 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-36628730

RESUMO

Hydrazine (N2H4) and hypochlorite (ClO-) are extremely harmful to the public health, so it is vitally necessary to detect them in living system. Herein, we developed a new phenthiazine-thiobarbituric acid based dual-analyte responsive fluorescent sensor PT for visually distinguishing and detecting N2H4 and ClO-. PT underwent N2H4/ClO--induced CC breakage, achieving olive-drab/brilliant green fluorescence lighting-up response towards N2H4/ClO- with superb specifity, ultra-sensitivity (detection limit: 15.4 nM for N2H4, 13.7 nM for ClO-), and ultra-fast response (N2H4: <15 s, ClO-: <20 s). The mechanisms for sensing N2H4 and ClO- were investigated with support of spectral measurements and DFT investigation. Sensor based paper-strip/silica-gel device was developed for in-field supervision and on-site monitoring of gaseous and aqueous N2H4 and ClO- solution. In addition, the PT was also applied for quantitatively detecting N2H4 and ClO- in soil, food, plants and bio-fluids. Moreover, PT was utilized to visualize exogenous N2H4 and ClO- in living plants and live-cells, demonstrating this sensor utilized as a powerful tool to detect N2H4 and ClO- in biological fields.


Assuntos
Corantes Fluorescentes , Ácido Hipocloroso , Humanos , Corantes Fluorescentes/farmacologia , Espectrometria de Fluorescência/métodos , Células HeLa , Hidrazinas
20.
Nano Lett ; 22(12): 4654-4660, 2022 06 22.
Artigo em Inglês | MEDLINE | ID: mdl-35653432

RESUMO

Photocorrosion of cuprous oxide (Cu2O) has notably limited its application as an efficient photocatalyst. We report a facile approach to visualize in situ formation of copper and oxygen vacancies on the Cu2O surface under ambient condition. By imaging photoexcited single Cu2O particles, the resultant photoluminescence generated at Cu2O surface enable effective localization of copper and oxygen vacancies. Single particle photoluminescence imaging showed substantial heterogeneity in the rate of defect formation at different facets with the truncated corners achieving the fastest initial rate of photooxidation before subsequently changing to the face and edge sites as the photocorrosion proceeds. The generation of copper or oxygen vacancy is proportional to the photoexcitation power, while pH-dependent studies rationalized alkaline conditions for the formation of copper vacancy. Reaction in an electron-hole scavenger system showed that photooxidation and photoreduction will simultaneously occur, yet heterogeneously on the surface of Cu2O, with rate of copper vacancy formation being fastest.


Assuntos
Cobre , Microscopia , Catálise , Cobre/química , Oxigênio
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