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Limited information is available on potential predictive value of environmental chemicals for mortality. Our study aimed to investigate the associations between 43 of 8 classes representative environmental chemicals in serum/urine and mortality, and further develop the interpretable machine learning models associated with environmental chemicals to predict mortality. A total of 1602 participants were included from the National Health and Nutrition Examination Survey (NHANES). During 154,646 person-months of follow-up, 127 deaths occurred. We found that machine learning showed promise in predicting mortality. CoxPH was selected as the optimal model for predicting all-cause mortality with time-dependent AUROC of 0.953 (95%CI: 0.951-0.955). Coxnet was the best model for predicting cardiovascular disease (CVD) and cancer mortality with time-dependent AUROCs of 0.935 (95%CI: 0.933-0.936) and 0.850 (95%CI: 0.844-0.857). Based on clinical variables, adding environmental chemicals could enhance the predictive ability of cancer mortality (P < 0.05). Some environmental chemicals contributed more to the models than traditional clinical variables. Combined the results of association and prediction models by interpretable machine learning analyses, we found urinary methyl paraben (MP) and urinary 2-napthol (2-NAP) were negatively associated with all-cause mortality, while serum cadmium (Cd) was positively associated with all-cause mortality. Urinary bisphenol A (BPA) was positively associated with CVD mortality.
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Doenças Cardiovasculares , Neoplasias , Humanos , Estudos Longitudinais , Inquéritos Nutricionais , Aprendizado de Máquina , Neoplasias/induzido quimicamenteRESUMO
BACKGROUND: Universities have widely switched from traditional face-to-face classes to online instruction as a result of the epidemic. Self-directed learning is becoming the new norm for university students' learning styles. The ability of health professions students to learn independently during online study directly impacts the effectiveness of online medical education. The ability to learn on their own initiative may be affected by health professions students' professional identities, defined as their positive perceptions, evaluations, emotional experiences, and identity as professionals related to medicine. This study aimed to look into the current status and the factors that influence health professions students' self-directed learning ability (SDLA) during online study and its relationship with professional identity. METHODS: This study was conducted from September to November 2022 at a medical school in East China. An online questionnaire was used to collect participants' status of online learning, self-directed learning ability (SDLA), and professional identity. RESULTS: One thousand two hundred ninety-eight health professions students demonstrated intermediate self-directed learning ability during online study. In terms of teacher-student interaction (F = 14.778, P < 0.001), student-student interaction (F = 15.713, P < 0.001), and learning concentration (F = 13.424, P < 0.001), there were significant differences in health professions students' self-directed learning ability. Professional identity and self-directed learning ability positively correlated (r = 0.589-0.802, P < 0.01). Academic atmosphere and professional identity were significant predictors. CONCLUSIONS: The self-directed learning ability of health professions students while receiving instruction online is at an intermediate level and is influenced by several factors. Developing health professions students' professional identities can enhance their ability for self-directed learning.
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Educação Médica , Estudantes de Ciências da Saúde , Estudantes de Medicina , Humanos , Estudantes de Medicina/psicologia , Aprendizagem , Ocupações em SaúdeRESUMO
Photonic crystals (PCs) have emerged as a promising electrochemiluminescence (ECL) matrix in the domain of immunoassay. Making maximum use of light manipulation properties of PCs is highly desired for improving the sensitivity. In this work, we proposed a band-edge effect-induced ECL enhancement strategy based on silica inverse opal PCs (SIOPCs). By fine-tuning the lattice constant and carefully calibrating the stopband position, we found that the band edge of the stopband exerted significant influences on the ECL intensity and spectral distribution. The high density of states at the blue edge of the photonic band gap increased the radiative transition probability of ECL emitters and enhanced the photon extraction during propagation, giving rise to â¼20-fold ECL signal amplification accompanied by a redistributed ECL spectrum for the Ru(bpy)32+-TPrA system. In combination with the intrinsic structural superiority, like large specific surface area and interconnected macropores, the developed SIOPC electrode was successfully applied in constructing a sandwich-type immunosensor. The fabricated immunosensor displayed a very low detection limit of 0.032 pg/mL and a wide linear range of 0.1 pg/mL-150 ng/mL for a carcinoembryonic antigen assay, showing its potential application in disease diagnosis.
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Técnicas Biossensoriais , Antígeno Carcinoembrionário , Técnicas Eletroquímicas , Imunoensaio , Limite de Detecção , Medições Luminescentes , Dióxido de Silício/químicaRESUMO
Emodin, a major component of Chinese herbal rhubarb, delays the progression of chronic renal failure. However, the effect and working mechanisms of Emodin on renal tubulointerstitial fibrosis remains elusive. We hypothesized that emodin inhibits renal tubulointerstitial fibrosis through EZH2, a histone methyltransferase. Our in vivo and in vitro studies demonstrate that emodin reduced extracellular collagen deposition and inhibited Smad3 and CTGF pro-fibrotic signaling pathways, which were correlated with the down-regulation of EZH2 and reduced trimethylation of histone H3 on lysine 27 (H3k27me3) in NRK-49F fibrotic cells and UUO kidneys. Inhibition of EZH2 by 3-DZNeP blocked or attenuated the anti-fibrotic effect of emodin in UUO kidneys and NRK-49F cells. These data indicate that emodin inhibits renal tubulointerstitial fibrosis in obstructed kidneys and this effect is mediated through EZH2.
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Emodina/farmacologia , Proteína Potenciadora do Homólogo 2 de Zeste/antagonistas & inibidores , Insuficiência Renal Crônica/tratamento farmacológico , Animais , Fator de Crescimento do Tecido Conjuntivo/antagonistas & inibidores , Modelos Animais de Doenças , Medicamentos de Ervas Chinesas/uso terapêutico , Inibidores Enzimáticos/farmacologia , Fibrose , Técnicas In Vitro , Rim/efeitos dos fármacos , Rim/metabolismo , Rim/patologia , Masculino , Ratos , Ratos Sprague-Dawley , Insuficiência Renal Crônica/metabolismo , Insuficiência Renal Crônica/patologia , Transdução de Sinais/efeitos dos fármacos , Proteínas Smad/antagonistas & inibidores , Obstrução Ureteral/tratamento farmacológico , Obstrução Ureteral/metabolismo , Obstrução Ureteral/patologiaRESUMO
BACKGROUND: This study aimed to detect the effect of angiotensin receptor 1 (AT1) knock out (KO) on spermatogenesis and hypothalamic-pituitary-gonadal (HPG) axis hormone expression. METHODS: Normal C57BL/6 male mice were used as control group or treated with angiotensin receptor blocker, in addition heterozygous ± AT1KO mice were generated. After caged at a ratio of 2 to 1 with females, pregnancy rates of female mice were determined by detection of vaginal plugs. Deformity rate of spermatozoa was evaluated by eosin staining and morphology evaluation. The AT1 mRNA expression in the testes of male ± AT1KO mice was detected by quantitative real-time polymerase chain reaction (QRT-PCR). Serum GnRH level was determined by ELISA. RESULTS: Compared to control, ± AT1KO mice showed reduced expression of AT1 in testes, pituitary and hypothalamus. In addition, decreased level of GnRH, but not follicle stimulating hormone (FSH) or luteinizing hormone (LH), in ± AT1KO mice was detected. Treatment with angiotensin receptor blocker (ARB) did not have significant effects on HPG hormones. ± AT1KO mice exhibited male infertility and significant abnormality of sperm morphology. CONCLUSION: Reduced AT1 knockout resulted in male infertility, potentially by inducing abnormal spermatogenesis. Both testis and HPG axis signaling may be involved.
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Hormônio Liberador de Gonadotropina/metabolismo , Infertilidade Masculina/genética , Receptor Tipo 1 de Angiotensina/genética , Espermatogênese/genética , Testículo/metabolismo , Bloqueadores do Receptor Tipo 1 de Angiotensina II/farmacologia , Animais , Hormônio Liberador de Gonadotropina/efeitos dos fármacos , Sistema Hipotálamo-Hipofisário/efeitos dos fármacos , Sistema Hipotálamo-Hipofisário/metabolismo , Hipotálamo/efeitos dos fármacos , Hipotálamo/metabolismo , Infertilidade Masculina/metabolismo , Losartan/farmacologia , Masculino , Camundongos , Camundongos Knockout , Hipófise/efeitos dos fármacos , Hipófise/metabolismo , Receptor Tipo 1 de Angiotensina/metabolismo , Espermatogênese/efeitos dos fármacos , Testículo/efeitos dos fármacosRESUMO
BACKGROUND: Studies have found that first primary cancer (FPC) survivors are at high risk of developing second primary breast cancer (SPBC). However, there is a lack of prognostic studies specifically focusing on patients with SPBC. METHODS: This retrospective study used data from Surveillance, Epidemiology and End Results Program. We selected female FPC survivors diagnosed with SPBC from 12 registries (from January 1998 to December 2018) to construct prognostic models. Meanwhile, SPBC patients selected from another five registries (from January 2010 to December 2018) were used as the validation set to test the model's generalization ability. Four machine learning models and a Cox proportional hazards regression (CoxPH) were constructed to predict the overall survival of SPBC patients. Univariate and multivariate Cox regression analyses were used for feature selection. Model performance was assessed using time-dependent area under the ROC curve (t-AUC) and integrated Brier score (iBrier). RESULTS: A total of 10,321 female FPC survivors with SPBC (mean age [SD]: 66.03 [11.17]) were included for model construction. These patients were randomly split into a training set (mean age [SD]: 65.98 [11.15]) and a test set (mean age [SD]: 66.15 [11.23]) with a ratio of 7:3. In validation set, a total of 3,638 SPBC patients (mean age [SD]: 66.28 [10.68]) were finally enrolled. Sixteen features were selected for model construction through univariate and multivariable Cox regression analyses. Among five models, random survival forest model showed excellent performance with a t-AUC of 0.805 (95 %CI: 0.803 - 0.807) and an iBrier of 0.123 (95 %CI: 0.122 - 0.124) on testing set, as well as a t-AUC of 0.803 (95 %CI: 0.801 - 0.807) and an iBrier of 0.098 (95 %CI: 0.096 - 0.103) on validation set. Through feature importance ranking, the top one and other top five key predictive features of the random survival forest model were identified, namely age, stage, regional nodes positive, latency, radiotherapy, and surgery. CONCLUSIONS: The random survival forest model outperformed CoxPH and other machine learning models in predicting the overall survival of patients with SPBC, which was helpful for the monitoring of high-risk populations.
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Neoplasias da Mama , Aprendizado de Máquina , Segunda Neoplasia Primária , Modelos de Riscos Proporcionais , Programa de SEER , Humanos , Feminino , Neoplasias da Mama/mortalidade , Pessoa de Meia-Idade , Idoso , Segunda Neoplasia Primária/mortalidade , Estudos Retrospectivos , Prognóstico , Curva ROC , Sobreviventes de Câncer/estatística & dados numéricosRESUMO
BACKGROUND: Alzheimer's disease (AD) is a progressive neurodegenerative disease with no effective therapies. It is well known that chronic neuroinflammation plays a critical role in the onset and progression of AD. Well-balanced neuronal-microglial interactions are essential for brain functions. However, determining the role of microglia-the primary immune cells in the brain-in neuroinflammation in AD and the associated molecular basis has been challenging. METHODS: Inflammatory factors in the sera of AD patients were detected and their association with microglia activation was analyzed. The mechanism for microglial inflammation was investigated. IL6 and TNF-α were found to be significantly increased in the AD stage. RESULTS: Our analysis revealed that microglia were extensively activated in AD cerebra, releasing sufficient amounts of cytokines to impair the neural stem cells (NSCs) function. Moreover, the ApoD-induced NLRC4 inflammasome was activated in microglia, which gave rise to the proinflammatory phenotype. Targeting the microglial ApoD promoted NSC self-renewal and inhibited neuron apoptosis. These findings demonstrate the critical role of ApoD in microglial inflammasome activation, and for the first time reveal that microglia-induced inflammation suppresses neuronal proliferation. CONCLUSION: Our studies establish the cellular basis for microglia activation in AD progression and shed light on cellular interactions important for AD treatment.
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The bismuth oxide (Bi2O3) based chloride (Cl-) removal method is one of the chemical precipitation methods possessing good selectivity and high removal efficiency of Cl- ions, but Bi2O3 often appears in the powder form, which is difficult to be recovered for regeneration. In this work, the combination of 3D printing technology and the Bi2O3 method was explored to construct the resin model including the Bi-precursors. In the optimum carbonization process at 400 °C for 30 min, the Bi3+ ions of the Bi-precursor were reduced into the metallic Bi0 nanoparticles, whose surfaces were covered by the thin Bi2O3 layers to form the heterostructured Bi0/Bi2O3 core/shell nanoparticles with an average size of 43 nm. These Bi0/Bi2O3 nanoparticles were tightly adhered to the internal and external surfaces of the hierarchical porous carbon model (Bi-PCM), which greatly facilitated their regeneration and ensured the stable Cl- removal performance. After five cycles of Cl- removal, the chloride removal efficiency over the multiple Bi-PCMs in the dark and pH 1 conditions maintained at about 26%, which then largely increased to 63.6% with UV light irradiation. The light-enhanced mechanism was related to the improved release rate of Bi3+ ions caused by photocorrosion and the Cl⢠radicals produced from the holes and the â¢OH and O2â¢- radicals, which quickly reacted with Bi2O3 to form BiOCl. The construction of Bi-PCMs by using 3D printing technology provides a very promising strategy for the removal of Cl- ions from wastewater.
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Bismuto , Águas Residuárias , Cloretos , Carbono , Porosidade , Pós , Halogênios , Impressão Tridimensional , TecnologiaRESUMO
As one of the well-known anticancer drugs, methotrexate (MTX) has been limited in clinical application due to its side effects on normal tissues. This study focused on the one-step hydrothermal synthesis and in vitro evaluation of Fe3O4/RGO-PEI as MTX carriers for targeted anticancer therapy. In which, the Fe3O4 provided magnetic response properties; RGO acted as a stage for Fe3O4 loading and improved the dispersion of Fe3O4; polyethylenimine (PEI) was used as a surface modifier and a storehouse for MTX. The prepared Fe3O4/RGO-PEI nanocomposites exhibited a suitable size, good stability and magnetic responsibility. And the MTX loading content and loading efficiency were calculated to be 26.6% and 90.5%, respectively. What's more, due to the diffusion and dissolution of PEI, the Fe3O4/RGO-PEI-MTX exhibited excellent pH-sensitivity, the values of MTX release rate (%) within 48 h at pH 5.8 and 4.0 were 64.3% and 87.4%, respectively. Furthermore, MTT assays in cancer cells (HepG2) and normal cells (HUVEC) demonstrated that Fe3O4/RGO-PEI-MTX exhibited high anticancer activity while low toxicity to normal cells, and also the Fe3O4/RGO-PEI composites were practically non-toxic. Thus, our results revealed that Fe3O4/RGO-PEI-MTX would be a competitive candidate for targeted delivery and controlled release of MTX.
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Metotrexato , Nanocompostos , Metotrexato/farmacologia , Metotrexato/química , Preparações de Ação Retardada , Nanocompostos/química , Polímeros , Polietilenoimina/química , Concentração de Íons de Hidrogênio , Fenômenos MagnéticosRESUMO
Background: Accumulating evidence suggests that traditional Chinese medicine (TCM) has significant effects on reducing 24-h urinary protein (24-h UPRO) and improves renal function indices. The current level of evidence-based medicine is still not enough due to the limitation of clinical center size and sample size. Objective: We aimed to update the current evidence on the efficacy of TCM in the treatment of diabetic kidney disease (DKD). Methods: PubMed, Embase, the Cochrane Library, and SinoMed were searched to identify randomized controlled trials (RCTs) comparing the clinical efficacy of TCM combined with Western medicine with that of Western medicine alone for the treatment of DKD. The main outcome measure was 24-h UPRO. The secondary outcomes were serum creatinine (Scr), blood urea nitrogen (BUN), glycosylated hemoglobin (HbA1c), fasting blood glucose (FBG), total cholesterol (TC), and triglyceride (TG). Meta-analyses were performed using random-effects models. The revised Cochrane risk-of-bias tool was used to assess the risk of bias. Results: A total of 44 RCTs with 3,730 participants were included. The summary estimates showed that compared with Western medicine alone, TCM combined with Western medicine significantly improved 24-h UPRO [standardized mean difference (SMD) -1.10, 95% confidence interval (CI) -1.45 to -0.74]. Moreover, TCM combined with Western medicine significantly reduced the levels of other renal function indices, including Scr (SMD -1.25, 95% CI: -1.69 to -0.81) and BUN (SMD -0.75, 95% CI: -1.10 to -0.40). TCM combined with Western medicine also showed greater benefits in reducing the levels of FBG (SMD -0.31, 95% CI: -0.47 to -0.15) and HbA1c (SMD -0.62, 95% CI: -0.89 to -0.36) in patients with DKD. In addition, superior effects on the lipid profile were noted in the TCM combined with Western medicine group in terms of TG (SMD -1.17, 95% CI: -1.76 to -0.59) and TC (SMD -0.95, 95% CI: -1.43 to -0.47). The risk of bias could have resulted from selective reports, unclear randomization methods, unblinded assignments, and some missing data. Conclusion: The results of this meta-analysis suggest that TCM combined with Western medicine has significant effects on reducing 24-h UPRO and improves renal function indices and lipid profiles compared with Western medicine alone for DKD. However, the results should be interpreted with caution due to the risk of bias of the included trials. Systematic Review Registration: [https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=213199], identifier [CRD: 42020213199].
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Ionic conductive hydrogels prepared from various biological macromolecules are ideal materials for the manufacture of human motion sensors from the perspective of resource regeneration and environmental sustainability. However, it is still challenging to prepare hydrogels with both high toughness and self-healing ability. In this study, lignin-based ß-CD-PVA (LCP) self-healing conductive hydrogels with high tensile properties were prepared by one-step method using alkali lignin as a plasticizer. Compared with PVA hydrogel, the maximum storage modulus and elongation were increased by 2.5 and 20.0 times, respectively. Uniform distribution of lignin can increase the fluidity and distance of polymer molecular chains, thus improving the viscoelastic and tensile properties of the LCP self-healing hydrogel. LCP hydrogels can maintain self-healing ability in both high (45 °C) and low temperature (0 °C) environments, and the self-healing ability is not affected by pH. Moreover, it also has good conductivity, anti-bacterial, thermostability, and anti-UV property, which has a good application prospect in the field of 3D printing and wearable electronic devices, which expands the efficient utilization of lignin in biorefinery.
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Hidrogéis , Dispositivos Eletrônicos Vestíveis , Humanos , Hidrogéis/farmacologia , Hidrogéis/química , Lignina , Condutividade Elétrica , AntibacterianosRESUMO
The metal doping at the Pb2+ position provides improved luminescence performance for the cesium lead halide perovskites, and their fabrication methods assisted by microwave have attracted considerable attention due to the advantages of fast heating and low energy consumption. However, the postsynthetic doping strategy of the metal-doped perovskites driven by microwave heating still lacks systematic research. In this study, the assembly of CsPbBr3/CsPb2Br5 with a strong fluorescence peak at 523 nm is used as the CsPbBr3 precursor, and through the optimization of the postsynthetic conditions such as reaction temperatures, Mn2+/Pb2+ feeding ratios, and Mn2+ sources, the optimum Mn2+-doped product (CsPb(Cl/Br)3:Mn) is achieved. The exciton fluorescence peak of CsPb(Cl/Br)3:Mn is blueshifted to 437 nm, and an obvious fluorescence peak attributing to the doped Mn2+ ions at 597 nm is obtained. Both the CsPbBr3 precursor and CsPb(Cl/Br)3:Mn have high PLQY and stability because there are CsPb2Br5 microcubic crystals to well disperse and embed the CsPbBr3 nanocrystals (NCs) in the precursor, and after Mn2+-doping, this structure is maintained to form CsPb(Cl/Br)3:Mn NCs on the surface of their microcrystals. The exploration of preparation parameters in the microwave-assisted method provides insights into the enhanced color-tunable luminescence of the metal-doped perovskite materials.
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Elemental composition determination of volatile organic compounds through high mass accuracy and isotope pattern matching could not be routinely achieved with a unit-mass resolution mass spectrometer until the recent development of the comprehensive instrument line-shape calibration technology. Through this unique technology, both m/z values and mass spectral peak shapes are calibrated simultaneously. Of fundamental importance is that calibrated mass spectra have symmetric and mathematically known peak shapes, which makes it possible to deconvolute overlapped monoisotopes and their (13)C-isotope peaks and achieve accurate mass measurements. The key experimental requirements for the measurements are to acquire true raw data in a profile or continuum mode with the acquisition threshold set to zero. A total of 13 ions from Chinese rose oil were analyzed with internal calibration. Most of the ions produced high mass accuracy of better than 5 mDa and high spectral accuracy of better than 99%. These results allow five tested ions to be identified with unique elemental compositions and the other eight ions to be determined as a top match from multiple candidates based on spectral accuracy. One of them, a coeluted component (Nerol) with m/z 154, could not be identified by conventional GC/MS (gas chromatography/mass spectrometry) and library search. Such effective determination for elemental compositions of the volatile organic compounds with a unit-mass resolution quadrupole system is obviously attributed to the significant improvement of mass accuracy. More importantly, high spectral accuracy available through the instrument line-shape calibration enables highly accurate isotope pattern recognition for unknown identification.
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Cromatografia Gasosa-Espectrometria de Massas/métodos , Óleos Voláteis/química , Óleos de Plantas/química , Rosa/química , Compostos Orgânicos Voláteis/análise , Calibragem , Extratos Vegetais/química , Compostos Orgânicos Voláteis/isolamento & purificaçãoRESUMO
For the first time, a new multifunctional nanomaterial which combined the superparamagnetic property of iron oxide nanoparticles with the fluorescent property of morin-Al3+ complex was prepared. Iron oxide nanoparticles were first coated with SiO2 which could isolate them from the complex and the surrounding. Subsequently, Al2O3 . nH2O which provided active aluminum atom were deposited on the silica shell. Finally, morin which would react with the reactive aluminum atom was added into the reaction mixture to prepare the final multifunctional nanomaterial. The obtained product was characterized by X-ray powder diffraction, transmission electron microscopy, fourier transform infrared spectra, photoluminescence spectra, fluorescence microscopy, and vibration sample magnetometer. The characterization results showed that the final samples had an average size of 60 nm with spherical shape. The saturation magnetization of this new synthesized material was about 8.5 emu g(-1). Its excitation and emission wavelengths were 420 and 513 nm, respectively.
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Óxido de Alumínio/química , Compostos Férricos/química , Flavonoides/química , Fluorescência , Nanopartículas/química , Dióxido de Silício/química , Óxido de Alumínio/síntese química , Flavonoides/síntese química , Magnetismo , Nanopartículas/ultraestrutura , Dióxido de Silício/síntese químicaRESUMO
Aim: It is already known that miRNAs can be differentially expressed in Alzheimer's disease (AD). We aimed to evaluate the performance of miRNAs from blood as potential biomarkers for AD. Materials & methods: MEDLINE, PubMed and Embase were searched for studies about peripheral blood miRNAs that could discriminate patients with AD from cognitively normal controls. The data regarding the specificity and sensitivity were extracted. STATA 14.0 was used to analyze the data. Results: Ten studies containing 770 AD and 664 normal controls. The analysis showed that miRNAs presented excellent diagnostic performance and the overall sensitivity was 0.80 (95% CI: 0.75-0.83), specificity was 0.83 (95% CI: 0.78-0.87) and diagnostic odds ratio was 14 (95% CI: 11-19). Subgroup analysis suggested that the Caucasian group and blood group showed a better performance in AD diagnosis and the diagnostic odds ratio was 42 and 34, respectively. Conclusion: This meta-analysis showed that miRNAs may be a promising biomarkers for AD.
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Doença de Alzheimer/sangue , MicroRNAs/sangue , Doença de Alzheimer/diagnóstico , Peptídeos beta-Amiloides/sangue , Biomarcadores/sangue , Humanos , Razão de ChancesRESUMO
With houttuynia cordata as carbon source, photoluminescent carbon quantum dots (CDs) were obtained via a one-step hydrothermal procedure. The absorption band of metronidazole (MNZ, maximum absorption wavelength at 319 nm) can well overlap with the excitation bands of CDs (maximum excitation wavelength at 320 nm). A fluorescent approach has been developed for detection of MNZ based on the inner filter effect (IFE), in which as-prepared CDs act as an IFE fluorophore and the MNZ as an IFE absorber. We have investigated the mechanism of quenching the fluorescence of CDs and found that the IFE leads to an exponential decay in fluorescence intensity of CDs with increasing concentration of MNZ, but showed a good linear relationship (R 2 = 0.9930) between ln(F 0/F) with the concentration of MNZ in the range of 3.3 × 10-6 to 2.4 × 10-4 mol L-1. Due to the absence of surface modification of the CDs or establishing any covalent linking between the absorber (MNZ) and the fluorophore (CDs), the developed method is simple, rapid, low-cost and less time-consuming. Meanwhile, it possesses a higher sensitivity, wider linear range, and satisfactory selectivity and has potential application for detection of MNZ in pharmaceutical preparations.
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In this work, fluorescence quenching technique, Fourier transform infrared (FT-IR) spectroscopy, circular dichroism (CD) spectroscopy and dynamic light scattering (DLS) technique were used to gain the binding information of caffeic acid and human serum albumin (HSA) in AOT/isooctane/water microemulsions. The interaction of HSA with caffeic acid at 296, 303, and 310 K in omega(0) 20 microemulsions was characterized by one binding site with the affinity constant K at (3.23+/-0.01) x 10(4), (3.06+/-0.03) x 10(4) and (2.82+/-0.05) x 10(4)M(-1), respectively. The affinities in microemulsions are much higher than that in buffer solution. The CD spectra and FT-IR spectra with qualitative and quantitative results proved that the protein secondary structure changed in the microemulsions in the absence and presence of caffeic acid compared with the free form of HSA in buffer. The binding process was exothermic and spontaneous, as indicated by the thermodynamic analyses. These data indicated that hydrophobic interaction played a major role in the binding of caffeic acid to HSA in microemulsions and electrostatic interaction can not be excluded. The displacement experiments confirmed that caffeic acid could bind to the site I of HSA, which was in agreement with the result of the molecular modeling study. Furthermore, the DLS data suggested that HSA may locate at the interface of the microemulsion and caffeic acid could interact with them.
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Ácidos Cafeicos/metabolismo , Membranas Artificiais , Albumina Sérica/metabolismo , Biomimética , Ácidos Cafeicos/química , Emulsões/química , Fluorescência , Modelos Moleculares , Ligação Proteica , Estrutura Secundária de Proteína , Albumina Sérica/química , Análise Espectral , Termodinâmica , Trometamina/químicaRESUMO
In this study, the interaction mechanism of herbicide glyphosate and human serum albumin (HSA) has been characterized by fluorescence, UV, Fourier transform infrared (FT-IR), Circular dichroism (CD) spectroscopic and molecular modeling methods. The structural characteristics of glyphosate and HSA were probed, and affinity constants were determined under different temperatures. The enthalpy change (DeltaH degrees ) and the entropy changes (DeltaS degrees ) were calculated to be -21.78kJmol(-1) and 6.38Jmol(-1)K(-1) according to the Van't Hoff equation. These results indicated that glyphosate binds to HSA mainly by hydrogen bond and hydrophobic interaction can also not be excluded, which is in good agreement with the results from modeling experiment. The average binding distance, r, between the donor (HSA) and the acceptor (glyphosate) was evaluated and found to be 2.89nm according to the Förster's theory of non-radiation energy transfer. The alterations of protein secondary structure in the presence of glyphosate were confirmed by the evidences from UV, FT-IR and CD spectroscopes.
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Glicina/análogos & derivados , Herbicidas/química , Modelos Moleculares , Albumina Sérica/química , Dicroísmo Circular , Glicina/química , Humanos , Ligação Proteica , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Espectrofotometria , Termodinâmica , GlifosatoRESUMO
There are only a few inorganic compounds that have evoked as much interest as sodium yttrium fluoride (NaYF4). Its extensive applications in various fields, including transparent displays, luminescence coding, data storage, as well as biological imaging, demand the precise tuning of the crystal phase. Controlling the emergence of the desired α-phase has so far remained a formidable challenge, especially via a simple procedure. Herein, we represented a polyol-assisted fluoride ions slow-release strategy for the rational control of pure cubic phase NaYF4 mesocrystals. The combination of fluorine-containing ionic liquid as a fluoride source and the existence of a polyalcohol as the reactive medium ensure the formation of uniform α-phase mesocrystallines in spite of a higher temperature and/or higher doping level.
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We established a system for the simultaneous extraction and cleaning of 99 veterinary drugs from food by ultra-performance liquid chromatography coupled with quadrupole electrostatic field-orbital trap-high-resolution mass spectrometry (UHPLC-Q-Orbitrap HRMS). The system is based on the supported liquid-liquid extraction technology through one-off pretreatment, which covers the common eight categories of physical and chemical properties, and the extraction and purification of 99 different veterinary drug residues. At the same time, the one-step multi residue screening of 99 veterinary drug residues has been realized using HRMS. The results showed that the method was suitable for extraction from milk, pork, and fish. The 99 veterinary drugs showed a good linear relationship in the concentration range of 0.001-0.1 µg/mL, the limit of quantification was 0.5-20.0 µg/kg, the average recoveries were 60%-120%, and the relative standard deviations (RSDs) were not more than 15%. The pre-processing and instrumental analysis of this method have high detection efficiency, strong maneuver ability, and strong compatibility with different physical and chemical compounds. Moreover, the detection limit can meet all the objects of the test and greatly reduce the detection cost.