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排序方式: 共有3923条查询结果,搜索用时 0 毫秒
101.
Gabriel A. Kurokawa Pedro T. Hamamoto Filho Jeany Delafiori Aline F. Galvani Arthur N. de Oliveira Flvia L. Dias-Audibert Rodrigo R. Catharino Maria Inês M. C. Pardini Marco A. Zanini Estela de O. Lima Adriana C. Ferrasi 《International journal of molecular sciences》2023,24(1)
Meningiomas (MGMs) are currently classified into grades I, II, and III. High-grade tumors are correlated with decreased survival rates and increased recurrence rates. The current grading classification is based on histological criteria and determined only after surgical tumor sampling. This study aimed to identify plasma metabolic alterations in meningiomas of different grades, which would aid surgeons in predefining the ideal surgical strategy. Plasma samples were collected from 51 patients with meningioma and classified into low-grade (LG) (grade I; n = 43), and high-grade (HG) samples (grade II, n = 5; grade III, n = 3). An untargeted metabolomic approach was used to analyze plasma metabolites. Statistical analyses were performed to select differential biomarkers among HG and LG groups. Metabolites were identified using tandem mass spectrometry along with database verification. Five and four differential biomarkers were identified for HG and LG meningiomas, respectively. To evaluate the potential of HG MGM metabolites to differentiate between HG and LG tumors, a receiving operating characteristic curve was constructed, which revealed an area under the curve of 95.7%. This indicates that the five HG MGM metabolites represent metabolic alterations that can differentiate between LG and HG meningiomas. These metabolites may indicate tumor grade even before the appearance of histological features. 相似文献
102.
Belen Calvo Miriam Fernandez Mercedes Rincon Pedro Tranque 《International journal of molecular sciences》2023,24(1)
The inhibition of Glycogen Synthase Kinase 3 β (GSK3β) by Ser9 phosphorylation affects many physiological processes, including the immune response. However, the consequences of GSK3β inhibition by alternative Ser389 phosphorylation remain poorly characterized. Here we have examined neuroinflammation in GSK3β Ser389 knock-in (KI) mice, in which the phosphorylation of Ser389 GSK3β is impaired. The number of activated microglia/infiltrated macrophages, astrocytes, and infiltrated neutrophils was significantly higher in these animals compared to C57BL/6J wild-type (WT) counterparts, which suggests that the failure to inactivate GSK3β by Ser389 phosphorylation results in sustained low-grade neuroinflammation. Moreover, glial cell activation and brain infiltration of immune cells in response to lipopolysaccharide (LPS) failed in GSK3β Ser389 KI mice. Such effects were brain-specific, as peripheral immunity was not similarly affected. Additionally, phosphorylation of the IkB kinase complex (IKK) in response to LPS failed in GSK3β Ser389 KI mice, while STAT3 phosphorylation was fully conserved, suggesting that the NF-κB signaling pathway is specifically affected by this GSK3β regulatory pathway. Overall, our findings indicate that GSK3β inactivation by Ser389 phosphorylation controls the brain inflammatory response, raising the need to evaluate its role in the progression of neuroinflammatory pathologies. 相似文献
103.
In this note, we investigate the finite‐sample properties of Moran's I test statistic for spatial autocorrelation in tobit models suggested by Kelejian and Prucha. We fill a void in the theoretical literature by investigating the finite sample properties of this test statistic in a series of Monte Carlo simulations, using data sets ranging from 49 to 15,625 observations. We find that the test is unbiased, has considerable power and approximates the asymptotic normal distribution even for medium‐sized sample sizes, empirically confirming the theoretical results of Kelejian and Prucha. However, some caution is needed, since the statistic turns out to be sensitive to misspecification in the form of heteroscedasticity. In such instances the test over‐rejects the null hypothesis, mistaking heteroscedasticity for spatial autocorrelation. 相似文献
104.
Júnior JB Araujo TA Trindade MA Ferreira VS 《International journal of cosmetic science》2012,34(1):91-96
An electroanalytical method was developed to detect and quantify the sunscreen agent octocrylene (OCR) in cosmetic products. The method was based on electrochemical reduction, using voltammetric techniques. OCR was reduced at -0.97 V vs. Ag/AgCl on a glassy carbon electrode using a mixture of Britton-Robinson buffer (0.04 mol L(-1)) and ethanol (7 : 3, v/v) as the supporting electrolyte solution. Under optimized conditions and square-wave voltammetry, OCR response was linear from 5.0 × 10(-6) to 8.0 × 10(-5) mol L(-1) (r = 0.9995), with a limit of detection of 2.8 × 10(-6) mol L(-1). The proposed electroanalytical method proved simple, fast and suitable for detection and quantification of OCR in samples of cosmetic products, with satisfactory results in the recovery test and analytical determination in real samples. 相似文献
105.
David Sanz Luis Mata Santiago Cond��n Mar��a ��ngeles Sanz Pedro Razquin 《Food Analytical Methods》2011,4(2):212-220
Concerns regarding the presence of drug residues in foods include allergic reactions, toxicity, technological problems in
fermented products and the development of antibiotic resistance in human pathogens. The analysis of antimicrobial residues
in foods is generally carried out, in a first step, through microbiological screening tests. These tests commonly use Geobacillus stearothermophilus as target specie but show a low ability to detect quinolones. The goal of our study was to evaluate the performance of a
new microbiological test (Equinox) for detection of quinolone residues in muscle. The kit contains an ampoule with a standardized
number of freeze-dried Escherichia coli and must be diluted with a specific detection medium containing a redox indicator. Microbial growth will modify the redox
potential of the medium being observed through a colour change (from blue to brown/orange). Equinox limits of detection for
most of tested quinolones (enrofloxacin, norfloxacin, sarafloxacin, marbofloxacin, ciprofloxacin, danofloxacin and difloxacin)
were below or around maximum residue limit (MRL) UE and CCβ values obtained corresponded with the determined sensitivities.
In contrast, flumequine could not be detected at MRL UE levels. Moreover, Equinox displayed a low sensitivity to other antimicrobials.
Sensitivity data obtained in vitro were consistent when testing incurred muscle samples. Matrix constituents, test batch and
animal species did not affect the performance of the test. Equinox could be easily automated enabling a large numbers of simultaneous
analysis, and a photometric reading can be applied for a precise interpretation. The results obtained in this study prove
that Equinox is a useful tool when screening for quinolone residues or can be combined with other methods for screening of
unknown samples. 相似文献
106.
107.
Process scale-up remains a considerable challenge for environmental applications of non-thermal plasmas.Undersanding the impact of reactor hydrodynamics in the performance of the process is a key step to overcome this challenge.In this work,we apply chemical engineering concepts to analyse the impact that different non-thermal plasma reactor configurations and regimes,such as laminar or plug flow,may have on the reactor performance.We do this in the particular context of the removal of pollutants by non-thermal plasmas,for which a simplified model is available.We generalise this model to different reactor configurations and,under certain hypotheses,we show that a reactor in the laminar regime may have a behaviour significantly different from one in the plug flow regime,often assumed in the non-thermal plasma literature.On the other hand,we show that a packed-bed reactor behaves very similarly to one in the plug flow regime.Beyond those results,the reader will find in this work a quick introduction to chemical reaction engineering concepts. 相似文献
108.
109.
110.
Pedro Delgado António ArêdeNelson Vila Pouca Patrício RochaAníbal Costa Raimundo Delgado 《Composite Structures》2012,94(4):1280-1287
Hollow bridge piers, particularly those built before the seventies, often have insufficient shear capacity due to inadequate transverse reinforcement details. Therefore, special attention must be given to this very important aspect when reinforced concrete (RC) piers with hollow sections are analysed and retrofitted. This paper covers the experimental analysis of retrofit solutions using CFRP sheets along the piers’ entire height to prevent shear failure. Experimental cyclic tests were carried out to evaluate the shear retrofit strategy efficiency on a set of RC piers with square hollow sections. This work also covers the study of design procedures for CFRP shear retrofitting and the evaluation of the associated ductility capacity improvement. The various transverse reinforcement detailing scenarios were assessed to determine their shear-failure prevention efficiency. The corresponding cyclic response behavior was also evaluated. The most relevant experimental information is presented in the paper, such as the evolution of the outer damage pattern. Finally, shear retrofit solutions, with a 40% increase over the maximum flexural force, show that this strategy is adequate to allow satisfactory ductility behavior. 相似文献