Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 17 de 17
Filtrar
1.
J Sep Sci ; 47(1): e2300620, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38066235

RESUMO

Herein, a magnetic borate-functionalized MXene composite with multiple boronic affinity sites was fabricated by embedding Fe3 O4 nanoparticles with 4-formylphenylboronic acid functionalized Ti3 C2 Tx nanosheets and served as sorbent for the simultaneous extraction of catecholamines (CAs) in urine samples. The morphology and structure of the magnetic materials were investigated using scanning microscopy, vibrating sample magnetometer, X-ray photoelectron spectrometer, and X-ray diffraction. The introduction of polyethyleneimine can amplify the bonded boronic acid groups, thereby effectively improving the adsorption capacities for CAs based on the multiple interactions of boronic affinity, hydrogen bonding, and metal coordination. The adsorption performance was investigated using the kinetics and isotherms models, and the main parameters that influence the extraction efficiency were optimized. Under the most favorable magnetic solid-phase extraction condition, a sensitive method for the analysis of CAs in urine samples was developed by combining magnetic solid-phase extraction conditions with high-performance liquid chromatography detection. The findings illustrated that the proposed approach possessed a wide linearity range of 0.05-250 ng/mL with an acceptable correlation coefficient (R2  ≥ 0.9984) and detection limits of 0.010-0.015 ng/mL for the target CAs. The research not only provides a notable composite with multiple boronic affinity sites but also offers an effective and feasible measure for the detection of CAs in biological samples.


Assuntos
Catecolaminas , Nanopartículas de Magnetita , Nitritos , Elementos de Transição , Polietilenoimina/química , Adsorção , Ácidos Borônicos/química , Cromatografia Líquida de Alta Pressão , Extração em Fase Sólida , Nanopartículas de Magnetita/química , Fenômenos Magnéticos
2.
Biomed Res Int ; 2023: 6435776, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37475819

RESUMO

Objectives: A series of laboratory parameters were screened to identify the proper serum markers that could be used to predict breast cancer recurrence at an early stage. Methods: A case-control retrospective study on 224 patients without postoperative recurrence and 43 patients with postoperative recurrence of breast cancer was performed. The edgeR software package was used to identify the test indicators expressed differently between the two groups. Univariate analysis was used to screen for diagnostic marker that could predict postoperative recurrence of breast cancer. In addition, the differential test indicators at different time points from surgery to recurrence were collected in patients with postoperative recurrence of breast cancer as a verification database. Results: We screened out three test indicators (TBA, GSP, and URBC) for differential expression, which were all expressed downregulated in the postoperative recurrence group of breast cancer. Univariate analysis suggested that only the difference in GSP levels between the two groups was statistically significant (P = 0.001). ROC curve analysis showed that the area under the curve of GSP was 0.662, while the area under the curve of GSP+AFP+CEA+CA125+CA153+age was increased to 0.828. In addition, serum GSP levels were significantly reduced after recurrence compared with before recurrence in breast cancer patients (P < 0.01). Conclusions: In summary, GSP could be used for early diagnosis of breast cancer recurrence after surgery, and the predicted value of combining GSP, tumor markers, and age was better than that of individual indicators.


Assuntos
Neoplasias da Mama , Humanos , Feminino , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/cirurgia , Estudos Retrospectivos , Antígeno Carcinoembrionário , Frutosamina , Recidiva Local de Neoplasia/patologia , Biomarcadores Tumorais/metabolismo
3.
Med Phys ; 50(9): 5434-5448, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37378868

RESUMO

BACKGROUND: Dynamic magnetic resonance imaging (DMRI) is an essential medical imaging technique, but the slow data acquisition process limits its further development. PURPOSE: By exploiting the inherent spatio-temporal correlation of MR images, low-rank tensor based methods have been developed to accelerate imaging. However, the tensor rank used by these methods is defined by an unbalanced matricization scheme, which cannot capture the global correlation of DMR data efficiently during the reconstruction process. METHODS: In this paper, an effective reconstruction model is proposed to achieve accurate reconstruction by using the tensor train (TT) rank defined by a well-balanced matricization scheme to exploit the hidden correlation of DMR data and combining sparsity. Meanwhile, the ket augmentation (KA) technology is introduced to preprocess the DMR data into a higher-order tensor through block structure addressing, which further improves the ability of TT rank to explore the local information of the image. In order to solve the proposed model, the alternating direction method of multipliers (ADMM) is used to decompose the optimization problem into several unconstrained subproblems. RESULTS: The performance of the proposed method was validated on the 3D DMR image dataset by using different sampling trajectories and sampling rates. Extensive numerical experiments demonstrate that the reconstruction quality of the proposed method is superior to several state-of-the-art reconstruction methods. CONCLUSIONS: The proposed method successfully utilizes the TT rank to explore the global correlation of DMR images, enabling more detailed information of the image to be captured. Besides, with the sparse priors, the proposed method can further improve the overall reconstruction quality for highly undersampled MR images.


Assuntos
Algoritmos , Imageamento por Ressonância Magnética , Imageamento por Ressonância Magnética/métodos , Imageamento Tridimensional , Processamento de Imagem Assistida por Computador/métodos
4.
Se Pu ; 41(7): 572-581, 2023 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-37387278

RESUMO

Neurotransmitters (NTs) are basic signaling chemicals used for communication between cells. The most well-known catecholamines (CAs) are epinephrine, norepinephrine, and dopamine. CAs are an important class of monoamine NTs that contain catechins and amine groups. The accurate determination of CAs in biological samples can provide essential information on potential pathogenic mechanisms. However, biological samples generally contain only trace levels of CAs. Therefore, sample pretreatment is necessary to separate and enrich CAs before instrument analysis. Dispersive solid-phase extraction (DSPE) technology combines the principles of liquid-liquid extraction and solid-phase extraction and is a useful method for purifying and enriching the target analytes in complex matrices. This method has the advantages of low solvent consumption, environmental safety, and high sensitivity and efficiency. In addition, the adsorbents used in DSPE do not need to be packed into a column and can simply be completely dispersed in the sample solution; this excellent feature greatly improves the extraction efficiency and simplifies the extraction process. Therefore, the development of new DSPE materials with high efficiency and adsorption capacity using simple preparation procedures has received wide attention from the research community. Carbon nitrides (MXenes) are a class of two-dimensional layered materials that possess good hydrophilicity, a large number of functional groups (-O, -OH, and -F), large layer spacing, different elemental compositions, excellent biocompatibility, and environmental friendliness. However, these materials have a small specific surface area and poor adsorption selectivity, which limits their applications in SPE. The separation selectivity of MXenes can be significantly improved by functional modification. Polyimide (PI) is a crosslinking product that is mainly formed by the condensation polymerization of binary anhydride and diamine. It has a unique crosslinked network structure, as well as a large number of carboxyl groups, and shows excellent characteristics. Therefore, the synthesis of new PI-functionalized Ti3C2Tx (Ti3C2Tx/PI) composites by growing a PI layer on the surface of two-dimensional MXene nanosheets in situ may not only overcome the adsorptive limitations of MXenes but also effectively improve their specific surface area and porous structure, thereby enhancing their mass transfer capacity, adsorption capacity, and selectivity. In this study, a Ti3C2Tx/PI nanocomposite was fabricated and successfully applied as a DSPE sorbent to enrich and concentrate trace CAs in urine samples. The prepared nanocomposite was examined using various characterization methods, including scanning electron microscopy, Fourier transform-infrared spectroscopy, X-ray diffraction, and zeta potential analysis. The effects of the extraction parameters on the extraction efficiency of Ti3C2Tx/PI were also investigated in detail. The adsorption performance of Ti3C2Tx/PI can be described by pseudo-second-order kinetics and the Freundlich isotherm model. The adsorption process appeared to occur on the outer surface, as well as surface voids, of the nanocomposite. The adsorption mechanism of Ti3C2Tx/PI indicated a chemical adsorption process based on multiple electrostatic, π-π, and hydrogen-bonding interactions. The optimal adsorption conditions included an adsorbent dosage of 20 mg, sample pH of 8, adsorption and elution times of 10 and 15 min, respectively, and eluent composed of acetic acid-acetonitrile-water (5∶47.5∶47.5, v/v/v). A sensitive method for detecting CAs in urine was subsequently developed by coupling Ti3C2Tx/PI as a DSPE sorbent with HPLC-FLD analysis. The CAs were separated on an Agilent ZORBAX ODS analytical column (250 mm×4.6 mm, 5 µm). Methanol and an aqueous solution of 20 mmol/L acetic acid were used as the mobile phases for isocratic elution. Under optimal conditions, the proposed DSPE-HPLC-FLD method exhibited good linearity in the range of 1-250 ng/mL with correlation coefficients >0.99. The limits of detection (LODs) and limits of quantification (LOQs) were calculated based on signal-to-noise ratios of 3 and 10 and found to be in the range of 0.20-0.32 and 0.7-1.0 ng/mL, respectively. The recoveries of the method were in the range of 82.50%-96.85% with RSDs≤9.96%. Finally, the proposed method was successfully applied to the quantification of CAs in urine samples from smokers and nonsmokers, thereby indicating its applicability for determining trace CAs.


Assuntos
Catecolaminas , Titânio , Cromatografia Líquida , Norepinefrina , Ácido Acético
5.
Anal Chim Acta ; 1237: 340581, 2023 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-36442935

RESUMO

In this study, covalent organic framework@MXene (COF@Ti3C2Tx) composites were synthesized and employed as solid phase microextraction coatings for isolation of polycyclic aromatic hydrocarbons (PAHs) from honey samples. The developed composites possessed unique structural characteristics and multiple interactions (π-π and hydrophobic interaction, etc.), which provided them with excellent extraction capacity towards the targeted PAHs. Under optimized conditions, the resultant COF@Ti3C2Tx-coating fiber-based HS-SPME/GC-FID method exhibited a wide linear range (2.0-2000 ng g-1), good linearities (r > 0.9964), and low limits of detection (0.20-0.60 ng g-1). The recoveries of PAHs in the honey samples were in the range of 73.2-112%, with RSDs less than 9.4%. In addition, the findings showed that the composite-based fiber offers a long lifetime, high enhancement factors (483-598), and excellent fiber-to-fiber reproducibility (RSDs <10.5%, n = 3). This work not only details the development of a multi-functional composite, but it also presents an effective strategy for the determination of trace PAHs in complex food matrix.


Assuntos
Mel , Estruturas Metalorgânicas , Hidrocarbonetos Policíclicos Aromáticos , Microextração em Fase Sólida , Reprodutibilidade dos Testes , Titânio
6.
Talanta ; 255: 124212, 2023 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-36566558

RESUMO

Acinetobacter baumannii (A. baumannii) is a common pathogen that causes hospital-acquired infections and is resistant to a wide variety of antibiotics. Consequently, the rapid and highly sensitive detection of A. baumannii is required during the early stages of infection. Therefore, we developed a DNA-catalyzed amplification mechanism based on aptamers, combined with a novel fluorescence resonance energy transfer (FRET) method based on graphene oxide (GO), for the detection of A. baumannii. In the presence of A. baumannii, an aptamer bound to A. baumannii, releasing the template strand, which triggered an entropy-driven catalysis (EDC) reaction. One EDC product was then used as the catalyst for catalytic hairpin assembly (CHA) on a GO nanosheet. Finally, the GO released a huge amount of FAM-labeled DNA duplices, which could be detected with FRET. This strategy circumvented the extraction of nucleic acids and was easy to execute, with a detection time of ≤1.5 h. The detection of A. baumannii with this method ranges from 5 cfu/mL to 1 × 105 cfu/mL, with a detection limit of 1.1 cfu/mL. The method was sufficiently sensitive and specific to detect A. baumannii rapidly in cerebrospinal fluid. In summary, our strategy provides a new option for the early detection and point-of-care testing (POCT) of A. baumannii infections, allowing their earlier and more precise treatment.


Assuntos
Acinetobacter baumannii , Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Transferência Ressonante de Energia de Fluorescência/métodos , Acinetobacter baumannii/genética , DNA , Aptâmeros de Nucleotídeos/genética , Catálise , Técnicas Biossensoriais/métodos
7.
Front Oncol ; 12: 945143, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36419885

RESUMO

Background: Circular RNAs (circRNAs) are receiving increasing attention as novel biomarkers. Our goal was to investigate the diagnostic, clinicopathological, and prognostic utility of circRNAs in prostate cancer (PCa). Methods: Relevant literature was searched in PubMed, Web of Science, and EMBASE. Sensitivity, specificity, diagnostic odds ratio (DOR), negative likelihood ratio (NLR), positive likelihood ratio (PLR), and the area under the curve (AUC) were calculated to evaluate the diagnostic accuracy of circRNA expression. circRNAs' clinical, pathological, and prognostic value was examined using pooled odds ratios (ORs) and hazard ratios (HRs). Results: This meta-analysis included 23 studies, with 5 for diagnosis, 16 for clinicopathological parameters, and 10 for prognosis. For diagnostic value, the pooled sensitivity, pooled specificity, PLR, NLR, DOR, and AUC were 0.82, 0.62, 2.17, 0.29, 7.37, and 0.81, respectively. Upregulation of carcinogenic circRNAs was associated with poor clinical parameters (Gleason score: OR = 0.222, 95% CI: 0.145-0.340; T classification: OR = 0.274, 95% CI: 0.175-0.430; lymph node metastasis: OR = 0.353, 95% CI: 0.175-0.716; tumor size: OR = 0.226, 95% CI: 0.099-0.518) and could predict poor survival outcomes (HR = 2.408, 95% CI: 1.559-3.720, p < 0.001). Conversely, downregulation of tumor-suppressor circRNAs was also associated with poor clinical parameters (Gleason score: OR = 1.689, 95% CI: 1.144-2.493; T classification: OR = 2.586, 95% CI: 1.779-3.762) and worse prognosis (HR = 1.739, 95% CI: 1.147-2.576, p = 0.006). Conclusion: Our results showed that circRNAs might be useful biomarkers for the diagnosis and prognosis of PCa. Systematic review registration: https://www.crd.york.ac.uk/prospero/, identifier CRD42021284785.

8.
Front Microbiol ; 13: 868152, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35602052

RESUMO

A tigecycline-resistant Acinetobacter pittii clinical strain from pleural fluid carrying a bla NDM-1 gene and a novel bla OXA gene, bla OXA-1045, was isolated and characterized. The AP2044 strain acquired two copies of the bla NDM-1 gene and six antibiotic resistance genes (ARGs) from other pathogens. According to the whole-genome investigation, the GC ratios of ARGs (50-60%) were greater than those of the chromosomal backbone (39.46%), indicating that ARGs were horizontally transferred. OXA-1045 belonged to the OXA-213 subfamily and the amino acid sequence of OXA-1045 showed 89% similarity to the amino acid sequences of OXA-213. Then, bla OXA-1045 and bla OXA-213 were cloned and the minimum inhibitory concentrations (MICs) of ß-lactams in the transformants were determined using the broth microdilution method. OXA-1045 was able to confer a reduced susceptibility to piperacillin and piperacillin-tazobactam compared to OXA-213. AP2044 strain exhibited low pathogenicity in Galleria mellonella infection models. The observation of condensed biofilm using the crystal violet staining method and scanning electron microscopy (SEM) suggested that the AP2044 strain was a weak biofilm producer. Quantitative reverse transcription-PCR (qRT-PCR) was used to detect the expression of resistance-nodulation-cell division (RND) efflux pump-related genes. The transcription level of adeB and adeJ genes increased significantly and was correlated with tigecycline resistance. Therefore, our genomic and phenotypic investigations revealed that the AP2044 strain had significant genome plasticity and natural transformation potential, and the emergence of antibiotic resistance in these unusual bacteria should be a concern for future investigations.

9.
J Anal Methods Chem ; 2022: 3998338, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35392281

RESUMO

Simple, rapid, and accurate detection of myoinositol (MI) concentration in blood is crucial in diagnosing polycystic ovary syndrome, neurological disorders, and cancer. A novel electrochemical detection (IED) method was established to quantify MI in human serum using a disposable unmodified screen-printed carbon electrode (SPCE) for the first time. MI was detected indirectly by the reaction product of myoinositol dehydrogenase (IDH) and cofactor ß-nicotinamide adenine dinucleotide (NAD+). Good linear calibration curves were obtained at the concentration range from 5.0 µM to 500.0 µM (R 2 = 0.9981) with the lower limits of detection (LOD) and quantification (LOQ) of 1.0 µM and 2.5 µM, respectively. Recoveries were calculated at three spiked concentrations, and the values were between 90.3 and 106%, with relative standard deviation values of 3.2-6.2% for intraday precision and 7.1-9.0% for interday precision. The SPCE-electrochemical biosensor is simple, accurate, and without modification, showing great potential for point-of-care testing (POCT) of serum MI in clinical samples.

10.
Anal Chim Acta ; 1189: 339182, 2022 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-34815041

RESUMO

Dysregulation of MicroRNAs (miRNAs) cause various diseases in humans, and developing reliable methods to detect miRNAs is critical for molecular diagnostics and personalized medicine. This study developed a toehold-mediated target invasion combined with duplex-specificity nuclease (DSN)-assisted cyclic signal amplification fluorescent sensor. Herein, we take advantage of toehold-mediated target invasion process to ensure the high selectivity of miRNA determination, coupled with the unique cleavage properties of DSN to improve the sensitivity of the strategy significantly. Throughout the assay, the whole procedure of detection the target let-7a has a limit of detection (LOD) as low as 9.00 fM and an excellent linear range from 1 pM to 100 nM for no more than 60 min. The assay shows reasonable specificity in detecting mismatched miRNAs and can realize single-base discrimination in the let-7 families. Finally, the developed method was applied to detect the miRNAs extracted from human serum. The results were consistent with those based on the quantitative reverse transcription-polymerase chain reaction(qRT-PCR) method, which shows great potential application value in clinical molecular diagnostics and biological research.


Assuntos
Técnicas Biossensoriais , MicroRNAs , Endonucleases , Humanos , Limite de Detecção , MicroRNAs/genética , Técnicas de Amplificação de Ácido Nucleico
11.
Talanta ; 238(Pt 1): 122987, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-34857321

RESUMO

Cytokeratin fragment antigen 21-1 (CYFRA21-1) is a sensitive marker for detecting non-small cell lung cancer (NSCLC). Ti3C2Tx modified by gold nanoparticles (AuNPs) and molybdenum disulfide (MoS2) were synthesized for the first time to obtain the AuNPs@MoS2@Ti3C2Tx composites, which have large specific surface area and good electrocatalytic properties. A novel electrochemical immunoassay for sensitive detection of CYFRA21-1 was developed by loading a large quantity of secondary antibodies (Ab2) and toluidine blue (TB) on the surface of the material as signal probe, and Nafion-AuNPs mixture as electrode material. When the electrochemical response value of CYFRA21-1 increased linearly within the concentration range of 0.5 pg mL-1-50 ng mL-1, the detection limit can reach as low as 0.03 pg mL-1. In addition, the experimental results showed that the biosensor had the potential to rapidly detect CYFRA21-1 in the complex samples such as patient serum, and had a broad application prospect in the early diagnosis and monitoring of NSCLC.


Assuntos
Técnicas Biossensoriais , Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Nanopartículas Metálicas , Antígenos de Neoplasias , Técnicas Eletroquímicas , Ouro , Humanos , Imunoensaio , Queratina-19 , Limite de Detecção , Neoplasias Pulmonares/diagnóstico , Molibdênio , Titânio
12.
Anal Chim Acta ; 1176: 338769, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34399896

RESUMO

A novel magnetic borate-modified MXene composite was prepared by in situ growth of Fe3O4 particles onto the surface of phenylboronic acid modified Ti3C2Tx nanosheets. The magnetic composite possesses highly selective recognition properties to catecholamines, and high adsorption capacity (up to 319.6 µmol g-1) for dopamine. Besides, the adsorption of urinary catecholamines can be accomplished within 2.0 min. The excellent adsorption performance can be assigned to its unique 2D layered structures, which helps to shorten the diffusion path and facilitate molecular transport. In addition, the multilayer adsorption and the synergetic interactions of borate affinity, van der Waals forces, hydrogen bonding and π-π stacking also contribute to the adsorption. By coupling the magnetic boronate affinity composites with high-performance liquid chromatography-fluorescence detection, a sensitive method for the determination of catecholamines in urine samples was proposed. The validation results revealed it can offer good linearities (correlation coefficients higher than 99%). The method detection limits were 0.06, 0.16, 0.03 and 0.14 ng mL-1 for norepinephrine, epinephrine, dopamine and isoprenaline, respectively, and relative recoveries for these catecholamines were in the range of 98.56-108.1%, 92.56-110.0%, 98.79-112.3% and 88.14-97.81%, respectively. The proposed method was successfully applied to analyze the catecholamines in the urine samples from 15 healthy volunteers and 16 patients with Alzheimer's disease. The results indicated that the magnetic borate-modified Mxene composite possesses superior extraction performance, and can be used as an outstanding candidate for the extraction of catecholamines in pre-clinical or clinical studies.


Assuntos
Boratos , Catecolaminas , Adsorção , Cromatografia Líquida de Alta Pressão , Humanos , Fenômenos Magnéticos , Magnetismo , Extração em Fase Sólida
13.
J Biosci ; 462021.
Artigo em Inglês | MEDLINE | ID: mdl-33576345

RESUMO

The protective effect of astrocytes on nerves was demonstrated by mitochondrial transfer. The neuroprotective effect of hypoxic pretreatment is widely accepted. The aim of this research is to investigate the role of hypoxic preconditioning on astrocytes mitochondria. Rat neuronal cells and astrocytes were isolated and cultured. A hypoxic preconditioned astrocyte and oxygen glucose deprivation (OGD) neuronal cell co-culture experiment was used to detect the effect of hypoxic preconditioning (HP) on nerve damage. The silencing of proliferatoractivated receptor γ coactivator-1α (PGC-1α) with siRNA was used to explore the role of HP in the repair of nerve damage and biogenesis of mitochondria. HP increased astrocyte viability and promoted neuroprotective factor secretion. The expression levels of antioxidant enzymes, PGC-1α and uncoupling protein2 (UCP2) were up-regulated by HP. In addition, HP improved mitochondrial function and reduced oxidative stress induced by OGD. It was found that HP astrocytes had a greater neuroprotective effect than normal astrocytes cells. Neuronal apoptosis and reactive oxygen species levels were down-regulated by cell co-culture. The PGC-1α siRNA experiment showed that hypoxia treatment promotes mitochondrial biogenesis and plays a neuroprotective role. HP significantly enhanced the efficacy of astrocytes in the treatment of neuronal injury.


Assuntos
Mitocôndrias/genética , Oxigênio/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/genética , Proteína Desacopladora 2/genética , Animais , Antioxidantes/farmacologia , Apoptose/genética , Astrócitos/metabolismo , Astrócitos/patologia , Glucose/metabolismo , Humanos , Hipóxia/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Neurônios/metabolismo , Neurônios/patologia , Estresse Oxidativo/genética , Ratos , Espécies Reativas de Oxigênio/metabolismo
14.
Nanoscale ; 13(2): 1134-1143, 2021 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-33399603

RESUMO

Highly active and stable bifunctional electrocatalysts for H2 generation from neutral-pH water are desired, but difficult to achieve. The modification of the electronic and crystal structure of a material by element doping, morphology design and constructing a complex is a valid strategy for obtaining high-performance catalysts toward overall water splitting. In this study, a novel Cu2-xSe@(Co,Cu)Se2 core-shell structure with ultrathin (Co,Cu)Se2 nanosheets anchored as a shell on an internal Cu2-xSe core was fabricated, for the first time, by integrating the three above-mentioned modification methods. Benefiting from the synergistic effect between components and the unique structure, the Cu2-xSe@(Co,Cu)Se2 core-shell structure can serve as an efficient bifunctional electrocatalyst for both HERs and OERs in neutral-pH electrolytes with a current density of 10 mA cm-2 at the overpotentials of 106 mV and 396 mV, respectively. Additionally, the material just requires a cell voltage of 1.73 V to afford a current density of 10 mA cm-2 in a neutral two-electrode electrolyzer. Such performances significantly outperform control catalysts and analogues. Even more importantly, the original concept of coordinated regulation presented in this work can broaden our horizons in the design of new and highly efficient catalysts for neutral water splitting.

15.
Sensors (Basel) ; 19(24)2019 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-31817145

RESUMO

A modified signal processing and target fusion detection method based on the dual platform cooperative detection model is proposed in this paper. In this model, a single transmitter and dual receiver radar system is adopted, which can form a single radar and bistatic radar system, respectively. Clutter suppression is achieved by an adaptive moving target indicator (AMTI). By combining the AMTI technology and the traditional radar signal processing technology (i.e., pulse compression and coherent accumulation processing), the SNR is improved, and false targets generated by direct wave are suppressed. The decision matrix is obtained by cell averaging constant false alarm (CA-CFAR) and order statistics constant false alarm (OS-CFAR) processing. Then, the echo signals processed in the two receivers are fused by the AND-like fusion rule and OR-like fusion rule, and the detection probability after fusion detection in different cases is analyzed. Finally, the performance of the proposed method is quantitatively analyzed. Experimental results based on simulated data demonstrate that: (1) The bistatic radar system with a split transceiver has a larger detection distance than the single radar system, but the influence of clutter is greater; (2) the direct wave can be eliminated effectively, and no false target can be formed after suppression; (3) the detection probability of the bistatic radar system with split transceivers is higher than that of the single radar system; and (4) the detection probability of signal fusion detection based on two receivers is higher than that of the bistatic radar system and single radar system.

16.
Artigo em Chinês | MEDLINE | ID: mdl-26653661

RESUMO

OBJECTIVE: To analyze the efficacy of Methylprednisolone hemisuccinate intratympanic injection for refractory noise induced deafness. METHODS: One hundred and twenty cases (215 ears) of noise induced deafness were treated with either hormone group (107 ears) or with non hormone group (108 ears). Following prior interventions, 145 ears went on to receive intratympanic Methylprednisolone hemisuccinate injection twice a week. RESULTS: After Intratympanic therapy, the total effective rate was 46.2%. 32 of 71 ears (45.1%) demonstrated hearing improvement in hormone group and 35 of 74 ears (47.3%) in non hormone group. The difference was statistically insignificant (P = 0.788). CONCLUSION: Intratympanic therapy appears to provide additional treatment benefits for patients with refractory noise induced deafness who have been treated with prior interventions. The outcome is not affected by pretreatment with hormone.


Assuntos
Glucocorticoides/uso terapêutico , Perda Auditiva Provocada por Ruído/tratamento farmacológico , Injeção Intratimpânica , Hemissuccinato de Metilprednisolona/uso terapêutico , Testes Auditivos , Humanos , Ruído , Resultado do Tratamento
17.
Artigo em Chinês | MEDLINE | ID: mdl-25007667

RESUMO

OBJECTIVE: To investigate the postoperative application of nasopharyngeal airway (NPA) in rhinogenous obstructive sleep apnea hypopnea syndrome (OSAHS) patients, so that to observe the parameters including vital signs of the patients and evaluatethe value of clinical application and reliability of NPA. METHOD: A total of 216 patients diagnosed as rhinogenous OSAHS were randomly assigned to experimental group (setting NPA, 112 cases) and control group (not setting NPA, 104 cases) according to whether NPA was placed in the nasal cavity postoperatively. ECG, oxygen saturation and hemodynamics were monitored for 24 h postoperatively. The pharyngeal pain and discomfort, low oxygen saturation and hemodynamics were compared between these two groups. The subjective assessment and clinical symptoms were compared between the two groups using visual analogue scale (VAS). RESULT: The experimental group showed better relief of nasal obstruction, nasal pain, headache, dry pharynx, insomnia and pain while taking out nasal packing compared with control group, where the differences were statistically significant (P < 0.01). In the experimental group, the level of LSa2O2 (P < 0.05), HR (P < 0.01), SBP (P < 0.05), DBP (P < 0.01), MAP (P < 0.01) and RPP (P < 0.01) was significantly lower than in the control group. CONCLUSION: The postoperative application of nasopharyngeal airway in rhinogenous OSAHS patients could help to keep nasal patency and avoid the upper airway obstruction, which exhibited good safety and compliance. The nasopharyngeal airway can reduce patients' discomfort and improve hyoxemia, ensuring hemodynamic stability.


Assuntos
Respiração Artificial/métodos , Apneia Obstrutiva do Sono/terapia , Adolescente , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Nasofaringe , Cuidados Pós-Operatórios , Adulto Jovem
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA