Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 54
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Sensors (Basel) ; 24(5)2024 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-38475239

RESUMO

The effective identification and mitigation of non-line-of-sight (NLOS) ranging errors are essential for achieving high-precision positioning and navigation with ultra-wideband (UWB) technology in harsh indoor environments. In this paper, an efficient UWB ranging-error mitigation strategy that uses novel channel impulse response parameters based on the results of a two-step NLOS identification, composed of a decision tree and feedforward neural network, is proposed to realize indoor locations. NLOS ranging errors are classified into three types, and corresponding mitigation strategies and recall mechanisms are developed, which are also extended to partial line-of-sight (LOS) errors. Extensive experiments involving three obstacles (humans, walls, and glass) and two sites show an average NLOS identification accuracy of 95.05%, with LOS/NLOS recall rates of 95.72%/94.15%. The mitigated LOS errors are reduced by 50.4%, while the average improvement in the accuracy of the three types of NLOS ranging errors is 61.8%, reaching up to 76.84%. Overall, this method achieves a reduction in LOS and NLOS ranging errors of 25.19% and 69.85%, respectively, resulting in a 54.46% enhancement in positioning accuracy. This performance surpasses that of state-of-the-art techniques, such as the convolutional neural network (CNN), long short-term memory-extended Kalman filter (LSTM-EKF), least-squares-support vector machine (LS-SVM), and k-nearest neighbor (K-NN) algorithms.

2.
Dev Biol ; 482: 82-90, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34915022

RESUMO

Adolescent idiopathic scoliosis (AIS) is a common pediatric musculoskeletal disorder worldwide, characterized by atypical spine curvatures in otherwise healthy children. Human genetic studies have identified candidate genes associated with AIS, however, only a few of these have been shown to recapitulate adult-viable scoliosis in animal models. Using an F0 CRISPR screening approach in zebrafish, we demonstrate that disruption of the dynein axonemal heavy chain 10 (dnah10) gene results in recessive adult-viable scoliosis in zebrafish. Using a stably segregating dnah10 mutant zebrafish, we showed that the ependymal monocilia lining the hindbrain and spinal canal displayed reduced beat frequency, which was correlated with the disassembly of the Reissner fiber and the onset of body curvatures. Taken together, these results suggest that monocilia function in larval zebrafish contributes to the polymerization of the Reissner fiber and straightening of the body axis.


Assuntos
Dineínas do Axonema , Cílios , Escoliose , Coluna Vertebral , Peixe-Zebra , Animais , Dineínas do Axonema/genética , Movimento Celular/genética , Cílios/genética , Cílios/metabolismo , Modelos Animais de Doenças , Morfogênese/genética , Escoliose/genética , Escoliose/fisiopatologia , Coluna Vertebral/embriologia , Coluna Vertebral/fisiologia , Peixe-Zebra/embriologia , Peixe-Zebra/genética , Proteínas de Peixe-Zebra/genética
3.
Sensors (Basel) ; 23(9)2023 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-37177383

RESUMO

Accurate altimetry is essential for location-based services in commercial and industrial applications. However, current altimetry methods only provide low-accuracy measurements, particularly in multistorey buildings with irregular structures, such as hollow areas found in various industrial and commercial sites. This paper innovatively proposes a tightly coupled indoor altimetry system that utilizes floor identification to improve height measurement accuracy. The system includes two optimized algorithms that improve floor identification accuracy through activity detection and address the problem of difficult convergence of z-axis coordinates due to indoor coplanarity by applying constraints to iterative least squares (ILS). Two experiments were conducted in a teaching building and a laboratory, including an irregular environment with a hollow area. The results show that our proposed method for identifying floors based on activity detection outperforms other methods. In dynamic experiments, our method effectively eliminates repeated transformations during the up- and downstairs process, and in static experiments, it minimizes the impact of barometric drift. Furthermore, our proposed altimetry method based on constrained ILS achieves significantly improved positioning accuracy compared to ILS, 1D-CNN, and WC. Specifically, in the teaching building, our method achieves improvements of 0.84 m, 0.288 m, and 0.248 m, respectively, while in the laboratory, the improvements are 2.607 m, 0.696 m, and 0.625 m.

4.
BMC Musculoskelet Disord ; 23(1): 797, 2022 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-35987623

RESUMO

BACKGROUND: Congenital scoliosis (CS) is a congenital deformity of the spine resulting from abnormal and asymmetrical development of vertebral bodies during pregnancy. However, the etiology and mechanism of CS remain unclear. Epigenetics is the study of heritable variations in gene expression outside of changes in nucleotide sequence. Among these, DNA methylation was described first and is the most characteristic and most stable epigenetic mechanism. Therefore, in this study, we aim to explore the association between genome methylation and CS which are not been studied before. METHODS: Two pairs of monozygotic twins were included, with each pair involving one individual with and one without CS. Agilent SureSelect XT Human Methyl-Sequencing was used for genome methylation sequencing. MethylTarget was used to detect methylation levels in target regions. Immunohistochemistry was performed to visualize expression of associated genes in candidate regions. RESULTS: A total of 75 differentially methylated regions were identified, including 24 with an increased methylation level and 51 with a decreased methylation level in the CS group. Nine of the differentially methylated regions were selected (TNS3, SEMAC3, GPR124, MEST, DLK1, SNTG1, PPIB, DEF8, and GRHL2). The results showed that the methylation level of the promoter region of TNS3 was 0.72 ± 0.08 in the CS group and 0.43 ± 0.06 in the control group (p = 0.00070 < 0.01). There was no significant difference in the degree of methylation of SEMAC3, GPR124, MEST, DLK1, SNTG1, PPIB, DEF8, or GRHL2 between the two groups. Immunohistochemistry showed significantly decreased TNS3 expression in the cartilage of the articular process in CS (CS: 0.011 ± 0.002; control: 0.018 ± 0.006, P = 0.003 < 0.01). CONCLUSION: Compared with the control group, high-level methylation of the TNS3 promoter region and low TNS3 expression in the cartilage layer of the articular process characterize CS. Thus, DNA methylation and TNS3 may play important roles in the pathogenesis of CS.


Assuntos
Escoliose , Tensinas , Sequência de Bases , Metilação de DNA , Epigênese Genética , Feminino , Humanos , Gravidez , Escoliose/genética , Tensinas/genética
5.
Sensors (Basel) ; 22(9)2022 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-35591286

RESUMO

The Wi-Fi fine time measurement (FTM) protocol specified in the IEEE 802.11-2016 standard provides a new two-way ranging approach to enhance positioning capability. Similar to other wireless signals, the accuracy of the real-time range measurement of FTM is influenced by various errors. In this work, the characteristics of the ranging errors is analyzed and an abstract ranging model is introduced. From the perspective of making full use of the range measurements from FTM, this paper designs two positioning steps and proposes a fusion method to refine the performance of indoor positioning. The first step is named single-point positioning, locating the position with the real-time range measurements based on the geometric principle. The second step is named the improved matching positioning, which constructs a distance database by utilizing the existing scene information and uses the modified matching algorithm to obtain the position. In view of the different positioning accuracies and error distributions from the results of the aforementioned two steps, a fusion method using the indirect adjustment principle is proposed to adjust the positioning results, and the advantages of the matching scene information and the range measurements are served simultaneously. Finally, a number of tests are conducted to assess the performance of the proposed method. The experimental results demonstrate that the precision and stability of indoor positioning are improved by the proposed fusion method.

6.
J Transl Med ; 18(1): 210, 2020 05 24.
Artigo em Inglês | MEDLINE | ID: mdl-32448279

RESUMO

BACKGROUND: The etiology of congenital scoliosis (CS) is complex and uncertain. Abnormal DNA methylation affects the growth and development of spinal development. In this study, we investigated the role of DNA methylation in CS. METHODS: The target region DNA methylation level in the peripheral blood of patients with CS was analyzed. Through in-depth analysis, genes closely related to the growth and development of the vertebra were identified. EdU staining was performed to verify the role of differentially expressed genes in chondrocyte proliferation. RESULTS: The hypermethylated KAT6B gene was observed in patients with CS, and was positively correlated with the Cobb angle. KAT6B was primarily expressed on chondrocytes. The promoter of KAT6B in CS patients was hypermethylated, and its expression was significantly reduced. Further mechanistic studies revealed that EZH2 mediated trimethylation of lysine 27 on histone H3 of the KAT6B promoter. Overexpression of KAT6B in CS-derived primary chondrocytes can significantly promote chondrocyte proliferation, which may be related to activation of the RUNX2/Wnt/ß-catenin signaling pathway. CONCLUSION: Epigenetic modification of KAT6B may be a cause of CS. If similar epigenetic modification abnormalities can be detected through maternal liquid biopsy screening, they may provide useful biomarkers for early screening and diagnosis of CS.


Assuntos
Lisina Acetiltransferases , Escoliose , Metilação de DNA/genética , Histonas/metabolismo , Humanos , Regiões Promotoras Genéticas/genética , Escoliose/genética
7.
Sensors (Basel) ; 20(4)2020 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-32053884

RESUMO

As pedestrian dead-reckoning (PDR), based on foot-mounted inertial sensors, suffers from accumulated error in velocity and heading, an improved heuristic drift elimination (iHDE) with a zero-velocity update (ZUPT) algorithm was proposed for simultaneously reducing the error in heading and velocity in complex paths, i.e., with pathways oriented at 45°, curved corridors, and wide areas. However, the iHDE algorithm does not consider the changes in pedestrian movement modes, and it can deteriorate when a pedestrian walks along a straight path without a pre-defined dominant direction. To solve these two problems, we propose enhanced heuristic drift elimination (eHDE) with an adaptive zero-velocity update (AZUPT) algorithm and novel heading correction algorithm. The relationships between the magnitude peaks of the y-axis angular rate and the detection thresholds were established only using the readings of the three-axis accelerometer and the three-axis gyroscopic, and a mechanism for constructing temporary dominant directions in real time was introduced. Real experiments were performed and the results showed that the proposed algorithm can improve the still-phase detection accuracy of a pedestrian at different movement motions and outperforms the iHDE algorithm in complex paths with many straight features.


Assuntos
Algoritmos , Navegação Espacial/fisiologia , Aceleração , , Heurística , Humanos , Sistemas Microeletromecânicos/instrumentação , Sistemas Microeletromecânicos/métodos , Pedestres , Corrida , Caminhada , Dispositivos Eletrônicos Vestíveis
8.
Sensors (Basel) ; 20(6)2020 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-32213874

RESUMO

This paper presents an evaluation of real-time kinematic (RTK)/Pseudolite/landmarks assistance heuristic drift elimination (LAHDE)/inertial measurement unit-based personal dead reckoning systems (IMU-PDR) integrated pedestrian navigation system for urban and indoor environments. Real-time kinematic (RTK) technique is widely used for high-precision positioning and can provide periodic correction to inertial measurement unit (IMU)-based personal dead reckoning systems (PDR) outdoors. However, indoors, where global positioning system (GPS) signals are not available, RTK fails to achieve high-precision positioning. Pseudolite can provide satellite-like navigation signals for user receivers to achieve positioning in indoor environments. However, there are some problems in pseudolite positioning field, such as complex multipath effect in indoor environments and integer ambiguity of carrier phase. In order to avoid the limitation of these factors, a local search method based on carrier phase difference with the assistance of IMU-PDR is proposed in this paper, which can achieve higher positioning accuracy. Besides, heuristic drift elimination algorithm with the assistance of manmade landmarks (LAHDE) is introduced to eliminate the accumulated error in headings derived by IMU-PDR in indoor corridors. An algorithm verification system was developed to carry out real experiments in a cooperation scene. Results show that, although the proposed pedestrian navigation system has to use human behavior to switch the positioning algorithm according to different scenarios, it is still effective in controlling the IMU-PDR drift error in multiscenarios including outdoor, indoor corridor, and indoor room for different people.


Assuntos
Algoritmos , Fenômenos Biomecânicos , Cidades , Heurística , Humanos , Pedestres
9.
Biochem Biophys Res Commun ; 518(2): 259-265, 2019 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-31421834

RESUMO

Adolescent idiopathic scoliosis (AIS) is a severe spinal deformity that often occurs during puberty. The occurrence of AIS is suggested to be related to abnormal development of cartilage. Our previous study found increased serum ghrelin levels in AIS patients that may linked to the development of AIS. However, whether ghrelin affects cartilage in AIS patients is unclear. We used quantitative real-time PCR (qRT-PCR) and immunohistochemistry to detect the expression of cartilage-specific genes and the ghrelin receptor, growth hormone secretagogue receptor (GHSR). The mRNA and protein levels of collagen II (COLII), SOX9, AGGRECAN (ACAN) and GHSR were higher in AIS patients than in controls. In addition, the protein levels of GHSR downstream signaling pathway members p-STAT3 (Ser727), and p-ERK1/2 were increased. Furthermore, we treated chondrocytes from AIS patients with 100 nM ghrelin, the cell proliferation assay and Western blotting showed that ghrelin promotes chondrocyte proliferation and enhances COLII, SOX9, ACAN, p-ERK1/2 and p-STAT3 expression, respectively. Interestingly, all these observed alterations were abolished by ghrelin + [D-Lys3]-GHRP-6 (a ghrelin receptor inhibitor) treatment. And after U0126 (an inhibitor of ERK1/2 phosphorylation) treatment, ERK1/2 and STAT3 (Ser727) phosphorylation was simultaneously suppressed indicating that ERK1/2 is an upstream pathway protein of STAT3 (Ser727). In conclusion, ghrelin plays an important role in upregulating cartilage-specific genes on AIS primary chondrocytes by activating ERK/STAT3 signaling pathway.


Assuntos
Condrócitos/efeitos dos fármacos , Grelina/farmacologia , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Fator de Transcrição STAT3/metabolismo , Escoliose/tratamento farmacológico , Regulação para Cima/efeitos dos fármacos , Regulação para Cima/genética , Adolescente , Agrecanas/genética , Agrecanas/metabolismo , Apoptose/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Criança , Condrócitos/metabolismo , Condrócitos/patologia , Colágeno Tipo II/genética , Colágeno Tipo II/metabolismo , Humanos , Fatores de Transcrição SOX9/genética , Fatores de Transcrição SOX9/metabolismo , Escoliose/metabolismo , Escoliose/patologia
10.
Pharmacology ; 103(1-2): 101-109, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30522105

RESUMO

It has been reported that taxifolin inhibit osteoclastogenesis in RAW264.7 cells. In our research, the inhibition effects of taxifolin on the osteoclastogenesis of human bone marrow-derived macrophages (BMMs) induced by receptor activator of NF-κB ligand (RANKL) as well as the protection effects in lipopolysaccharide-induced bone lysis mouse model have been demonstrated. In vitro, taxifolin inhibited RANKL-induced osteoclast differentiation of human BMMs without cytotoxicity. Moreover, taxifolin significantly suppressed RANKL-induced gene expression, including tartrate-resistant acid phosphatase, matrix metalloproteinase-9 nuclear factor of activated T cells 1 and cathepsin K, and F-actin ring formation. Further studies showed that taxifolin inhibit osteoclastogenesis via the suppression of the NF-κB signaling pathway. In vivo, taxifolin prevented bone loss in mouse calvarial osteolysis model. In conclusion, the results suggested that taxifolin has a therapeutic potential for osteoclastogenesis-related diseases such as osteoporosis, osteolysis, and rheumatoid arthritis.


Assuntos
Reabsorção Óssea/induzido quimicamente , Reabsorção Óssea/tratamento farmacológico , Lipopolissacarídeos/farmacologia , Macrófagos/efeitos dos fármacos , Osteogênese/efeitos dos fármacos , Quercetina/análogos & derivados , Ligante RANK/antagonistas & inibidores , Actinas/metabolismo , Animais , Catepsina K/metabolismo , Diferenciação Celular/efeitos dos fármacos , Modelos Animais de Doenças , Humanos , Quinase I-kappa B/metabolismo , Macrófagos/citologia , Masculino , Metaloproteinase 9 da Matriz/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , NF-kappa B/genética , NF-kappa B/metabolismo , Fatores de Transcrição NFATC/metabolismo , Osteólise/induzido quimicamente , Osteólise/tratamento farmacológico , Osteólise/patologia , Quercetina/farmacologia , Ligante RANK/farmacologia , Células RAW 264.7 , Transdução de Sinais , Fator de Transcrição RelA/metabolismo
11.
BMC Musculoskelet Disord ; 20(1): 479, 2019 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-31653238

RESUMO

BACKGROUND: Adolescent idiopathic scoliosis (AIS) which characterized by complex three-dimensional deformity of spine has been difficult to cure because of the unknown etiopathology and uncertainty of progression. Nowadays, circulating cell-free (ccf) DNA was found to be a potential biomarker for several benign and malignant diseases. However, whether ccf DNA can be a biomarker for AIS has not been reported yet. In this study, we investigate the circulating cell-free nuclear DNA (ccf n-DNA) and mitochondrial DNA (ccf mt-DNA) concentrations in the plasma of patients with AIS and controls (CT), and the changed plasma ccf n-DNA and ccf mt-DNA levels and their association with clinical parameters were assessed. METHODS: The plasma of peripheral blood from 69 AIS patients and 21 age-matched CT was collected for ccf DNA analysis. Quantitative PCR was used to detect ccf n-DNA and ccf mt-DNA levels, and correlation analyses between the ccf n-DNA and ccf mt-DNA levels and clinical characteristics were conducted. Receiver operator curves (ROC) were used to analyze the sensitivity and specificity of ccf n-DNA and ccf mt-DNA levels to different characteristics. RESULTS: The plasma ccf n-DNA levels of both GAPDH and ACTB were significantly decreased in AIS patients compared with those in controls, while the plasma ccf mt-DNA levels did not changed. According to sex-related analyses, the ccf n-DNA levels in male CT-M was higher than that in female CT and male AIS, but the ccf n-DNA levels in female AIS was not significantly changed when compared with male AIS or female CT. However, the concentration of ccf mt-DNA in female AIS increased significantly when compared with male AIS. Surprisingly, Lenke type-related analyses suggested that Lenke type 1 patients had lower ccf n-DNA levels, whereas Lenke type 5 patients had higher ccf mt-DNA levels compared with those of controls. However, a lower sensitivity and specificity of AIS predicted by ccf n-DNA or ccf mt-DNA levels was observed, whether in total, by sex, or by Lenke type. CONCLUSION: Although with no/little predictive accuracy of AIS/progressed AIS by ccf DNA levels, significantly changed plasma ccf DNA levels were observed in AIS patients compared with those in controls.


Assuntos
Ácidos Nucleicos Livres/sangue , DNA Mitocondrial/sangue , Escoliose/diagnóstico , Actinas/genética , Adolescente , Biomarcadores/sangue , Núcleo Celular/genética , Ácidos Nucleicos Livres/isolamento & purificação , Criança , DNA Mitocondrial/isolamento & purificação , Progressão da Doença , Feminino , Gliceraldeído-3-Fosfato Desidrogenase (Fosforiladora)/genética , Humanos , Masculino , Valor Preditivo dos Testes , Reação em Cadeia da Polimerase em Tempo Real , Estudos Retrospectivos , Escoliose/sangue , Escoliose/genética , Sensibilidade e Especificidade , Fatores Sexuais
12.
Sensors (Basel) ; 19(12)2019 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-31234289

RESUMO

Trusted positioning data are very important for the fusion of Bluetooth fingerprint positioning (BFP) and Wi-Fi fingerprint positioning (WFP). This paper proposes an adaptive Bluetooth/Wi-Fi fingerprint positioning method based on Gaussian process regression (GPR) and relative distance (RD), which can choose trusted positioning results for fusion. In the offline stage, measurements of the Bluetooth and Wi-Fi received signal strength (RSS) were collected to construct Bluetooth and Wi-Fi fingerprint databases, respectively. Then, fingerprint positioning error prediction models were built with GPR and data from the fingerprint databases. In the online stage, online Bluetooth and Wi-Fi RSS readings were matched with the fingerprint databases to get a Bluetooth fingerprint positioning result (BFPR) and a Wi-Fi fingerprint positioning result (WFPR). Then, with the help of RD and fingerprint positioning error prediction models, whether the positioning results are trusted was determined. The trusted result is selected as the position estimation result when there is only one trusted positioning result among the BFPR and WFPR. The mean is chosen as the position estimation result when both the BFPR and WFPR results are trusted or untrusted. Experimental results showed that the proposed method was better than BFP and WFP, with a mean positioning error of 2.06 m and a root-mean-square error of 1.449 m.

13.
Sensors (Basel) ; 19(3)2019 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-30744141

RESUMO

The radio map construction is usually time-consuming and labor-sensitive in indoor fingerprinting localization. We propose a fast construction method by using an adaptive path loss model interpolation. Received signal strength (RSS) fingerprints are collected at sparse reference points by using multiple smartphones based on crowdsourcing. Then, the path loss model of an access point (AP) can be built with several reference points by the least squares method in a small area. Afterwards, the RSS value can be calculated based on the constructed model and corresponding AP's location. In the small area, all models of detectable APs can be built. The corresponding RSS values can be estimated at each interpolated point for forming the interpolated fingerprints considering RSS loss, RSS noise and RSS threshold. Through combining all interpolated and sparse reference fingerprints, the radio map of the whole area can be obtained. Experiments are conducted in corridors with a length of 211 m. To evaluate the performance of RSS estimation and positioning accuracy, inverse distance weighted and Kriging interpolation methods are introduced for comparing with the proposed method. Experimental results show that our proposed method can achieve the same positioning accuracy as complete manual radio map even with the interval of 9.6 m, reducing 85% efforts and time of construction.

14.
Sensors (Basel) ; 18(8)2018 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-30071642

RESUMO

The human body has a great influence on Wi-Fi signal power. A fixed K value leads to localization errors for the K-nearest neighbor (KNN) algorithm. To address these problems, we present an adaptive weighted KNN positioning method based on an omnidirectional fingerprint database (ODFD) and twice affinity propagation clustering. Firstly, an OFPD is proposed to alleviate body's sheltering impact on signal, which includes position, orientation and the sequence of mean received signal strength (RSS) at each reference point (RP). Secondly, affinity propagation clustering (APC) algorithm is introduced on the offline stage based on the fusion of signal-domain distance and position-domain distance. Finally, adaptive weighted KNN algorithm based on APC is proposed for estimating user's position during online stage. K initial RPs can be obtained by KNN, then they are clustered by APC algorithm based on their position-domain distances. The most probable sub-cluster is reserved by the comparison of RPs' number and signal-domain distance between sub-cluster center and the online RSS readings. The weighted average coordinates in the remaining sub-cluster can be estimated. We have implemented the proposed method with the mean error of 2.2 m, the root mean square error of 1.5 m. Experimental results show that our proposed method outperforms traditional fingerprinting methods.

15.
Biochem Biophys Res Commun ; 490(1): 36-43, 2017 08 12.
Artigo em Inglês | MEDLINE | ID: mdl-28579433

RESUMO

Taxifolin, a flavonoid compound, has been reported to stimulate osteogenic differentiation in osteoblasts. The present study investigated whether taxifolin affects the osteogenic differentiation of human bone marrow mesenchymal stem cells (hBMSCs) and the molecular mechanisms involved. The proliferation and osteogenic differentiation of hBMSCs in the presence of taxifolin were examined by CCK-8 assay, alkaline phosphatase (ALP) activity, ALP staining and Alizarin red staining. The expression of osteogenic differentiation markers were detected by real-time quantitative PCR (RT-PCR) analysis and western blot assay. The activation of potential related pathways was examined by luciferase reporter assay, immunofluorescence and western blot analysis. Taxifolin treatment increased osteogenic differentiation of hBMSCs without cytotoxicity. Luciferase reporter assay showed that taxifolin could not activate estrogen receptor pathway, but inhibit TNF-α-induced NF-κB signaling pathway activation in osteogenic induction condition. Moreover, the nucleus translocation of NF-κB under TNF-α treatment was inhibited by taxifolin treatment. The taxifolin-induced osteogenic differentiation effects of hBMSCs were abolished by TNF-α treatment. In conclusion, our results suggested that taxifolin could promote osteogenesis of hBMSCs, partially through antagonism of NF-κB signaling pathway.


Assuntos
Diferenciação Celular/efeitos dos fármacos , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/efeitos dos fármacos , NF-kappa B/metabolismo , Osteogênese/efeitos dos fármacos , Quercetina/análogos & derivados , Transdução de Sinais/efeitos dos fármacos , Células Cultivadas , Relação Dose-Resposta a Droga , Humanos , Células-Tronco Mesenquimais/metabolismo , Estrutura Molecular , Transporte Proteico/efeitos dos fármacos , Quercetina/farmacologia , Relação Estrutura-Atividade
16.
Neurochem Res ; 42(8): 2208-2217, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28316021

RESUMO

This study aimed to investigate the mechanism underlying the neuroprotective effect of hemin in oxygen-glucose deprivation (OGD)-treated neurons. OGD-treated SH-SY5Y cells (human neuroblastoma cells) were used in the study. The cellular viability of SH-SY5Y cells was assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and the cell apoptosis rate was determined by flow cytometry analysis with Annexin V-fluorescein isothiocyanate and propidium iodide staining with or without hemin pretreatment. Cell viability and apoptotic activation were detected after hemin administration combined with neuroglobin (Nqb), thioredoxin-1, peroxiredoxin-2, or heme oxygenase-1 siRNA transient transfection. The release of cytochrome c from mitochondria and the interaction between Ngb and cytochrome c were examined with hemin pretreatment. Hemin had a neuroprotective effect in OGD-treated SH-SY5Y cells, which was mainly mediated by the upregulation of Ngb. Moreover, the release of cytochrome c from mitochondria was inhibited by hemin-induced Ngb expression through facilitating the interaction of Ngb with cytochrome c in mitochondria. The present findings provided new insights into the neuroprotective mechanisms of hemin. It was concluded that low-dose hemin pretreatment had a neuroprotective effect in OGD-treated SH-SY5Y cells, through inhibiting cell apoptosis. The neuroprotective effects of hemin following hypoxic-ischemic neuronal damage were mainly mediated by Ngb. One underlying mechanism was hemin-induced overexpression of mitochondrial Ngb, which inhibited endogenous apoptosis via the association with cytochrome c.


Assuntos
Apoptose/fisiologia , Globinas/biossíntese , Glucose/deficiência , Hemina/farmacologia , Proteínas do Tecido Nervoso/biossíntese , Neurônios/metabolismo , Fármacos Neuroprotetores/farmacologia , Apoptose/efeitos dos fármacos , Hipóxia Celular/efeitos dos fármacos , Hipóxia Celular/fisiologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Humanos , Neuroglobina , Neurônios/efeitos dos fármacos
17.
Guang Pu Xue Yu Guang Pu Fen Xi ; 37(2): 361-7, 2017 Feb.
Artigo em Zh | MEDLINE | ID: mdl-30264962

RESUMO

The atmospheric aerosols have significant influence on human health, the environment and the climate system. The atmospheric boundary layer (ABL) reflects processes of the near-surface atmosphere and concentration of pollutants. Ground-based laser radar can monitor the vertical distribution of atmospheric aerosols stably and continuously. It provides dynamic information for timing observations of the ABL and environmental forecasting, if aerosols can be monitored and evaluated using lidar technology. There is a gap in the study of ABL observations during the presence of a residual layer and aerosol intrusion, as well as deficiencies in the accuracy and poor computational efficiency of the gradient method. This paper combines the physical meaning of the latter method with characteristics of a lidar timing chart and local optimum model, which based on space-time proximity. Then a polarization-Mie scattering lidar system is used to observe the vertical distribution of aerosols over time at Taihu observation site, which is in a newly developed area of the city of Wuxi, Jiangsu Province, China. Observation and analysis is carried out for two cases in terms of pollution at the end of 2012. Then corresponding estimation model was built with gradient method and local optimum model based on range-corrected signals. In the case of steady weather and mixed pollution, results of the gradient method and local optimum model were very similar. However, the gradient method has more error in the case of pollution intrusion with the residual layer. The local optimum model based on the space-time proximity theory considers vertical eigenvalues and horizontal correlations, thereby greatly reducing the effects of low clouds, signal interference, weak signals, bi-layered aerosols, and residual layer condition. Compared with the gradient method, the local optimum model had a smaller O(n) and greater stability in computer automatic identification. ABL identification in the case with the residual layer and aerosol intrusion was solved with use of lidar technology and the local optimum model. The accuracy and computational efficiency problems of the gradient method were resolved using automatic operation.

18.
Biochem Biophys Res Commun ; 479(4): 920-926, 2016 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-27634221

RESUMO

SRY-related high-mobility-group box 9 (Sox9) gene is a transcription factor that plays an essential role in chondrocyte differentiation and cartilage formation. In this study, we identified the transcriptional factor ZNF606 as an interacting partner for Sox9 in cells. We further demonstrated that overexpression of ZNF606 inhibited the transcriptional activity of Sox9, while knockdown of ZNF606 increased Sox9-mediated transcription. Chromatin immunoprecipitation analysis revealed that ZNF606 prevents Sox9 binding to the enhancers of its target gene col2a1. Importantly, the interaction between ZNF606 and Sox9 was decreased during chondrocyte differentiation. Consistent with these findings, ZNF606 inhibited chondrocyte differentiation. Thus, our results demonstrate that ZNF606 acts as a novel Sox9 co-regulator that inhibits Sox9-mediated chondrocyte differentiation.


Assuntos
Condrócitos/citologia , Condrócitos/metabolismo , Condrogênese/fisiologia , Proteínas Repressoras/metabolismo , Fatores de Transcrição SOX9/metabolismo , Diferenciação Celular/genética , Diferenciação Celular/fisiologia , Células Cultivadas , Condrogênese/genética , Colágeno Tipo II/genética , Elementos Facilitadores Genéticos , Técnicas de Silenciamento de Genes , Células HEK293 , Humanos , Células MCF-7 , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/metabolismo , Ligação Proteica , Proteínas Repressoras/antagonistas & inibidores , Proteínas Repressoras/genética , Fatores de Transcrição SOX9/antagonistas & inibidores , Fatores de Transcrição SOX9/genética , Regulação para Cima
19.
Int J Mol Sci ; 17(7)2016 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-27447624

RESUMO

To investigate the underlying mechanisms of low metabolic activity of primary chondrocytes obtained from girls with adolescent idiopathic scoliosis (AIS); AIS is a spine-deforming disease that often occurs in girls. AIS is associated with a lower bone mass than that of healthy individuals and osteopenia. Leptin was shown to play an important role in bone growth. It can also regulate the function of chondrocytes. Changes in leptin and Ob-R levels in AIS patients have been reported in several studies. The underlying mechanisms between the dysfunction of peripheral leptin signaling and abnormal chondrocytes remain unclear; The following parameters were evaluated in AIS patients and the control groups: total serum leptin levels; Ob-R expression in the plasma membrane of primary chondrocytes; JAK2 and STAT3 phosphorylation status. Then, we inhibited the lysosome and proteasome and knocked down clathrin heavy chain (CHC) expression in primary chondrocytes isolated from girls with AIS and evaluated Ob-R expression. We investigated the effects of leptin combined with a lysosome inhibitor or CHC knockdown in primary chondrocytes obtained from AIS patients; Compared with the controls, AIS patients showed similar total serum leptin levels, reduced JAK2 and STAT3 phosphorylation, and decreased cartilage matrix synthesis in the facet joint. Lower metabolic activity and lower membrane expression of Ob-R were observed in primary chondrocytes from the AIS group than in the controls. Lysosome inhibition increased the total Ob-R content but had no effect on the membrane expression of Ob-R or leptin's effects on AIS primary chondrocytes. CHC knockdown upregulated the membrane Ob-R levels and enhanced leptin's effects on AIS primary chondrocytes; The underlying mechanism of chondrocytes that are hyposensitive to leptin in some girls with AIS is low plasma membrane Ob-R expression that results from an imbalance between the rate of receptor endocytosis and the insertion of newly synthesized receptors into the membrane.


Assuntos
Condrócitos/metabolismo , Leptina/metabolismo , Doenças Metabólicas/etiologia , Receptores para Leptina/metabolismo , Escoliose/fisiopatologia , Adolescente , Adulto , Western Blotting , Condrócitos/citologia , Ensaio de Imunoadsorção Enzimática , Feminino , Imunofluorescência , Humanos , Doenças Metabólicas/metabolismo , Doenças Metabólicas/patologia , Microscopia Confocal , Reação em Cadeia da Polimerase em Tempo Real , Receptores para Leptina/genética , Adulto Jovem
20.
Environ Monit Assess ; 188(2): 97, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26780416

RESUMO

Hyperspectral estimation of soil organic matter (SOM) in coal mining regions is an important tool for enhancing fertilization in soil restoration programs. The correlation--partial least squares regression (PLSR) method effectively solves the information loss problem of correlation--multiple linear stepwise regression, but results of the correlation analysis must be optimized to improve precision. This study considers the relationship between spectral reflectance and SOM based on spectral reflectance curves of soil samples collected from coal mining regions. Based on the major absorption troughs in the 400-1006 nm spectral range, PLSR analysis was performed using 289 independent bands of the second derivative (SDR) with three levels and measured SOM values. A wavelet-correlation-PLSR (W-C-PLSR) model was then constructed. By amplifying useful information that was previously obscured by noise, the W-C-PLSR model was optimal for estimating SOM content, with smaller prediction errors in both calibration (R(2) = 0.970, root mean square error (RMSEC) = 3.10, and mean relative error (MREC) = 8.75) and validation (RMSEV = 5.85 and MREV = 14.32) analyses, as compared with other models. Results indicate that W-C-PLSR has great potential to estimate SOM in coal mining regions.


Assuntos
Minas de Carvão , Monitoramento Ambiental/métodos , Solo/química , Calibragem , Análise dos Mínimos Quadrados , Modelos Lineares , Modelos Teóricos
SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa