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1.
Heliyon ; 10(11): e31686, 2024 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-38828324

RESUMEN

In order to achieve numerical optimization of the pod pepper seed sowing device, the contact parameters of pod pepper seeds were calibrated, with the angle of repose used as the response value. A set of discrete element method (DEM) models of pod pepper seeds was developed to simulate the formation of seed repose angles using reverse engineering reconstruction techniques. An eight-factor, three-level response surface experiment based on the Box-Behnken central combination test method was performed to study the effects of various factors on the angle of repose of seeds. The angle of repose obtained from physical experiments with a value of 27.56° was taken as the target value. The optimal combination of parameters is obtained as follows: seed Poisson's ratio of 0.22, seed shear modulus of 15.47 MPa, seed-to-seed static friction coefficient of 0.25, seed-to-seed rolling friction coefficient of 0.67, seed-to-seed collision recovery coefficient of 0.64, seed-to-steel-plate static friction coefficient of 0.55, seed-to-steel-plate rolling friction coefficient of 0.45, and seed-to-steel plate collision recovery coefficient of 0.34. A two-sample t-test of the angle of repose obtained by the cylinder lifting method and the pumping plate method against the target value yielded P > 0.05, indicating the reliability of the simulation experiments.

2.
Sensors (Basel) ; 23(11)2023 May 30.
Artículo en Inglés | MEDLINE | ID: mdl-37299927

RESUMEN

Post-ripening fruits need to be ripened to reach edible conditions, as they are not yet mature enough when picked. Ripening technology is based mainly on temperature control and gas regulation, with the proportion of ethylene being one of the key gas regulation parameters. A sensor's time domain response characteristic curve was obtained through the ethylene monitoring system. The first experiment showed that the sensor has good response speed (maximum of first derivative: 2.01714; minimum of first derivative: -2.01714), stability (xg: 2.42%; trec: 2.05%; Dres: 3.28%), and repeatability (xg: 20.6; trec: 52.4; Dres: 2.31). The second experiment showed that optimal ripening parameters include color, hardness (Change Ⅰ: 88.53%, Change Ⅱ: 75.28%), adhesiveness (Change Ⅰ: 95.29%, Change Ⅱ: 74.72%), and chewiness (Change Ⅰ: 95.18%, Change Ⅱ: 74.25%), verifying the response characteristics of the sensor. This paper proves that the sensor was able to accurately monitor changes in concentration which reflect changes in fruit ripeness, and that the optimal parameters were the ethylene response parameter (Change Ⅰ: 27.78%, Change Ⅱ: 32.53%) and the first derivative parameter (Change Ⅰ: 202.38%, Change Ⅱ: -293.28%). Developing a gas-sensing technology suitable for fruit ripening is of great significance.


Asunto(s)
Etilenos , Frutas , Frutas/fisiología , Temperatura , Dureza , Proteínas de Plantas
3.
BMC Cancer ; 23(1): 593, 2023 Jun 27.
Artículo en Inglés | MEDLINE | ID: mdl-37370037

RESUMEN

BACKGROUND: The lack of effective and accurate predictive indicators remains a major bottleneck for the improvement of the prognosis of patients with hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC). Hepatitis B virus X (HBx) has been widely suggested as a critical pathogenic protein for HBV-driven liver carcinogenesis, while tumor-associated macrophage (TAM) infiltration is also closely related to the tumorigenesis and progression of HCC. However, few studies have determined whether combining HBx expression with TAM populations could increase the accuracy of prognostic prediction for HBV-related HCC. METHODS: The study cohort enrolling 251 patients with HBV-related HCC was randomly split into a training and a validation group (ratio 1:1). The expression levels of HBx and TAM marker CD68 in HCC samples were detected by immunohistochemistry. Kaplan-Meier curves, Cox regression and Harrell's concordance index (C-index) analysis were conducted to evaluate the prognostic significance of these indicators alone or in combination. RESULTS: The expression level of HBx was strongly correlated with CD68+ TAM infiltration in HCC tissues. Elevated HBx or CD68 expression indicated poorer overall survival (OS) and progression-free survival (PFS) after hepatectomy, and both of them were independent risk factors for postoperative survival. Meanwhile, patients with both high HBx and CD68 levels had worst clinical outcomes. Moreover, integrating HBx and CD68 expression with clinical indicators (tumor size and micro-vascular invasion) showed the best prognostic potential with highest C-index value for survival predictivity, and this proposed model also performed better than several conventional classifications of HCC. CONCLUSION: Combining the expression of intratumoral HBx, CD68+ TAM population and clinical variables could enable better prognostication for HBV-related HCC after hepatectomy, thus providing novel insights into developing more effective clinical prediction model based on both molecular phenotypes and tumor-immune microenvironment.


Asunto(s)
Carcinoma Hepatocelular , Neoplasias Hepáticas , Humanos , Carcinoma Hepatocelular/genética , Neoplasias Hepáticas/genética , Pronóstico , Macrófagos Asociados a Tumores/metabolismo , Modelos Estadísticos , Virus de la Hepatitis B/genética , Biomarcadores/metabolismo , Microambiente Tumoral
4.
ACS Omega ; 6(26): 17002-17018, 2021 Jul 06.
Artículo en Inglés | MEDLINE | ID: mdl-34250358

RESUMEN

Shale gas reservoirs are tight reservoirs with ultralow porosity and ultralow permeability, and their matrix pores are mostly nanoscale. In addition, matrix particles and organic pore surfaces adsorb shale gas. These problems cause the production per well of shale gas to be lower than that of conventional natural gas. The use of hydraulic fracturing technology to exploit shale gas can achieve a good production increase effect. However, using this technology has some limitations caused by technical characteristics and geological conditions. Therefore, new technologies for shale gas exploitation need to be explored. In this study, we propose a method to improve the flow characteristics of shale gas by using ultrasonic waves to increase shale gas production and perform experimental tests to research the actual effect of this method. The lithology, mineral composition, pore structure, specific surface area, and pore size distribution of shale samples are tested. Then, the attenuation characteristics of ultrasonic waves propagating in shale are analyzed. Finally, the effect of ultrasonic waves on the adsorption, desorption, and seepage of shale gas is explored. Results show that the Langmuir adsorption isotherm can describe the adsorption characteristics of shale gas under the action of ultrasonic waves. The gas adsorption constant decreases with increasing ultrasonic wave power. The ultrasonic waves accelerate the gas desorption rate, significantly increase the desorption volume, and prolong the time taken to reach desorption equilibrium. They also increase the permeability of shale gas, and the growth is proportional to the power of the ultrasonic waves. These results indicate that the permeability of shale gas has a power function relationship with the effective stress under ultrasonic waves.

5.
Cancer Immunol Immunother ; 70(10): 2925-2935, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-33710368

RESUMEN

PURPOSE: Identification of reliable postoperative indicators for accurately evaluating prognosis of clear cell renal cell carcinoma (ccRCC) patients remains an important clinical issue. This study determined the prognostic value of UBR5 expression in ccRCC patients by combining with CD163+ tumor-associated macrophages (TAMs) and the established clinical parameters. METHODS: The expression of UBR5 was analyzed in ccRCC patients from TCGA databases. A total of 310 ccRCC patients were randomly divided into the training and validation cohorts at a 3:2 or 1:1 ratio, and immunohistochemistry (IHC) and statistical analyses were performed to examine the prognostic value of UBR5 and CD163+ TAMs. RESULTS: UBR5 expression was commonly downregulated in human ccRCC specimens, which was associated with TNM stage, SSIGN, WHO/ISUP Grading and poor prognosis of ccRCC patients. In addition, UBR5 expression was negatively correlated with CD163 expression (a TAM marker) in ccRCC tissues, and combining expressions of UBR5 and CD163 better predicted worse overall survival and progression-free survival of ccRCC patients. Even after multivariable adjustment, UBR5, CD163, TNM stage and SSIGN appeared to be independent risk factors. By time-dependent c-index analysis, the integration of intratumoral UBR5 and CD163 achieved higher c-index value than UBR5, CD163, TNM stage or SSIGN alone in predicting ccRCC patients' prognosis. Moreover, the incorporation of both UBR5 and CD163 into the clinical indicators TNM stage or SSIGN exhibited highest c-index value. CONCLUSIONS: Integrating intratumoral UBR5 and CD163+ TAMs with the current clinical parameters achieves better accuracy in predicting ccRCC patients' postoperative prognosis.


Asunto(s)
Antígenos CD/metabolismo , Antígenos de Diferenciación Mielomonocítica/metabolismo , Carcinoma de Células Renales/genética , Neoplasias Renales/genética , Macrófagos/metabolismo , Receptores de Superficie Celular/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Carcinoma de Células Renales/patología , Femenino , Humanos , Neoplasias Renales/patología , Masculino , Pronóstico , Estudios Retrospectivos , Factores de Riesgo
6.
Front Oncol ; 11: 697697, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-35360452

RESUMEN

Ferroptosis is a cell death process discovered in recent years, highly related to cancer, acute kidney injury, and other diseases. In this study, a pan-renal cancer analysis of ferroptosis-associated genes in renal cancer was performed to construct a multigene joint signature for predicting prognosis in renal cancer patients. First, gene expression profiles were downloaded from the TCGA and GTEx databases to search for genes significantly associated with renal cancer prognosis through differential gene expression analysis, weighted gene co-expression network analysis (WGCNA), and survival analysis. Thereafter, the gene-set enrichment analysis (GSEA) was used to identify the biological processes in which ferroptosis-associated genes might be involved. Weighted gene co-expression network analysis resulted in 4,434 differentially expressed genes (DEGs) and 42 co-expression modules, among which ferroptosis-related genes were distributed in 11 gene modules. The survival analysis screening resulted in three DEGs associated with renal cancer prognosis, namely SLC7A11, HMOX1, and MT1G. Specifically, SLC7A11 and HMOX1 were upregulated in renal cancer tissues, while MT1G was downregulated. Receiver operating characteristic (ROC) curves, combined with Kaplan-Meier and Cox regression analysis, revealed that high expression of SLC7A11 was a prognostic risk factor for four different renal cancers, that low expression of HMOX1 was a poor prognostic marker for patients, and that increased expression of MT1G increased the prognostic risk for three additional classes of renal cancer patients, except for renal papillary cell carcinoma. The GSEA results showed that the ferroptosis-related genes from these screens were mainly associated with signaling pathways related to tumor progression and tumor immunity. This study provides potential biological markers for prognosis prediction in renal cancer patients with different subtypes, and these results imply that ferroptosis is highly associated with renal carcinogenesis progression.

7.
Cell Death Differ ; 28(3): 932-951, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-33009518

RESUMEN

Although the interaction between tumors and tumor-associated macrophages (TAMs) has been reported to facilitate the targeted drug resistance and progression of clear cell renal cell carcinoma (ccRCC), the related mechanisms remain unknown. Here, we report that SOX17 serves as a novel tumor suppressor in ccRCC and a positive regulatory loop, SOX17low/YAP/TEAD1/CCL5/CCR5/STAT3, facilitates the ccRCC-TAM interaction. SOX17 expression was commonly downregulated and negatively correlated with TAM infiltration in ccRCC specimens, and the integration of SOX17 and TAMs with the existing clinical indicators TNM stage or SSIGN score achieved better accuracy for predicting the prognosis of ccRCC patients. Mechanistically, SOX17 knockdown activated YAP signaling by promoting the transcription and nuclear distribution of YAP, which recruited TEAD1 to trigger CCL5 transcription. Then, CCL5 educated macrophages toward TAMs, which reciprocally enhanced ccRCC progression through CCL5/CCR5 and activated STAT3/SOX17low/YAP. However, SOX17 overexpression in ccRCC achieved the opposite effect. Thus, a positive regulatory loop, SOX17low/YAP/TEAD1/CCL5/CCR5/STAT3, was identified in the ccRCC-TAM interaction. Furthermore, targeting tumor-TAM interactions by blocking this positive regulatory network impaired the metastasis and targeted drug resistance of ccRCC in in vivo mouse models of lung metastasis and orthotopic ccRCC. These findings provide a new mechanism underlying the tumor-TAM interplay in ccRCC progression and present a potential target for inhibiting targeted drug resistance and metastasis in advanced ccRCC.


Asunto(s)
Carcinoma de Células Renales/genética , Neoplasias Renales/genética , Animales , Biomarcadores de Tumor/genética , Carcinoma de Células Renales/patología , Línea Celular Tumoral , Humanos , Neoplasias Renales/patología , Masculino , Ratones , Ratones Endogámicos NOD , Ratones Desnudos , Pronóstico , Transducción de Señal , Macrófagos Asociados a Tumores , Ensayos Antitumor por Modelo de Xenoinjerto
8.
Oncoimmunology ; 9(1): 1736793, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32313718

RESUMEN

A helpful evaluation system is crucial for the postoperative prognosis prediction of clear cell renal cell carcinoma (ccRCC) patients. This study determined the prognostic value of combining intratumoral RASSF10 expression and tumor-associated macrophages (TAMs) with the established clinicopathological indicators in ccRCC patients. RASSF10 expression was analyzed in ccRCC patient data from online databases and ccRCC cell lines. Two independent ccRCC patient cohorts were employed to examine the prognostic value of RASSF10 and other markers by immunohistochemistry (IHC) and statistical analyses. We found that RASSF10 expression was downregulated in ccRCC specimens from the TCGA datasets and three independent institutions. RASSF10 expression was negatively correlated with disease progression and TAM infiltration in ccRCC. In addition, low RASSF10 expression and high TAM infiltration predicted a high TNM stage, SSIGN score, WHO/ISUP grading, and a poor prognosis in two independent ccRCC patient cohorts. Moreover, RASSF10, CD68 or CD163, TNM stage, and SSIGN score were identified as independent risk factors in predicting ccRCC patients' prognosis. Time-dependent c-index analyses revealed that the combination of RASSF10 and TAMs resulted in a higher index than that resulting from each alone in the postoperative prognosis of ccRCC patients, and the integration of RASSF10 and TAMs with the TNM stage or SSIGN score achieved the best accuracy in assessing the prognosis of ccRCC patients. These findings were validated in the randomized training, validation, and combined cohorts. Taken together, the combination of the RASSF10-TAM classifier and current clinical parameters yields superior accuracy in predicting the ccRCC patients' postoperative outcome.


Asunto(s)
Carcinoma de Células Renales , Neoplasias Renales , Biomarcadores de Tumor/genética , Carcinoma de Células Renales/genética , Humanos , Neoplasias Renales/genética , Estadificación de Neoplasias , Nefrectomía , Pronóstico , Proteínas Supresoras de Tumor/genética , Macrófagos Asociados a Tumores
9.
Cell Death Dis ; 11(2): 117, 2020 02 12.
Artículo en Inglés | MEDLINE | ID: mdl-32051393

RESUMEN

The poor prognosis of clear-cell renal cell carcinoma (ccRCC) patients is due to progression and targeted drug resistance, but the underlying molecular mechanisms need further elucidation. This study examined the biological function and related mechanisms of gankyrin in ccRCC based on the results of our previous study. To this end, in vitro functional experiments; in vivo models of subcutaneous tumor formation, lung metastasis, and orthotopic ccRCC; and antibody chip detection, co-IP, ChIP assays were performed to examine the biological role and molecular mechanisms of gankyrin in ccRCC. Two hundred fifty-six ccRCC patients were randomly divided into training and validation cohorts to examine the prognostic value of gankyrin and other markers through IHC and statistical analyses. We observed that the gankyrin-overexpressing ccRCC cell lines 786-O and 769-P exhibited increased proliferation, invasion, migration, tumorigenicity, and pazopanib resistance and decreased apoptosis, while gankyrin knockdown achieved the opposite results. Mechanistically, gankyrin recruited STAT3 via direct binding, and STAT3 binding to the CCL24 promoter promoted its expression. Reciprocally, an increase in autocrine CCL24 enhanced the expression of gankyrin and STAT3 activation via CCR3 in ccRCC, forming a positive autocrine-regulatory loop. Furthermore, in vivo experimental results revealed that blocking the positive loop through gankyrin knockdown or treatment with the CCR3 inhibitor SB328437 reversed the resistance to pazopanib and inhibited lung metastasis in ccRCC. Moreover, a positive correlation between gankyrin and STAT3 or CCL24 expression in ccRCC specimens was observed, and improved accuracy for ccRCC patient prognosis was achieved by combining gankyrin and STAT3 or CCL24 expression with existing clinical prognostic indicators, including the TNM stage and SSIGN score. In summary, targeting the gankyrin/STAT3/CCL24/CCR3 autocrine-regulatory loop may serve as a remedy for patients with advanced ccRCC, and combining gankyrin and STAT3 or CCL24 expression with the current clinical indicators better predicts ccRCC patient prognosis.


Asunto(s)
Antineoplásicos/farmacología , Comunicación Autocrina/efectos de los fármacos , Carcinoma de Células Renales/tratamiento farmacológico , Quimiocina CCL24/metabolismo , Resistencia a Antineoplásicos , Neoplasias Renales/tratamiento farmacológico , Complejo de la Endopetidasa Proteasomal/metabolismo , Proteínas Proto-Oncogénicas/metabolismo , Pirimidinas/farmacología , Receptores CCR3/metabolismo , Factor de Transcripción STAT3/metabolismo , Sulfonamidas/farmacología , Animales , Carcinoma de Células Renales/genética , Carcinoma de Células Renales/metabolismo , Carcinoma de Células Renales/secundario , Línea Celular Tumoral , Quimiocina CCL24/genética , Progresión de la Enfermedad , Resistencia a Antineoplásicos/genética , Regulación Neoplásica de la Expresión Génica , Humanos , Indazoles , Neoplasias Renales/genética , Neoplasias Renales/metabolismo , Neoplasias Renales/patología , Masculino , Ratones Endogámicos NOD , Ratones SCID , Complejo de la Endopetidasa Proteasomal/genética , Proteínas Proto-Oncogénicas/genética , Receptores CCR3/genética , Factor de Transcripción STAT3/genética , Transducción de Señal , Carga Tumoral/efectos de los fármacos , Ensayos Antitumor por Modelo de Xenoinjerto
10.
Transl Cancer Res ; 9(12): 7550-7561, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-35117355

RESUMEN

BACKGROUND: The pervasive progression of renal cell carcinoma (RCC) after treatment demands more effective drugs with few side effects. In the present study, we determined whether degalactotigonin (DGT) extracted from Solanum nigrum L. could exert antitumoral effects on RCC and examined the related molecular mechanisms. METHODS: The effects of DGT on RCC cells were assessed by cell counting kit-8 (CCK-8) assay, flow cytometry, invasion and migration assays and subcutaneous tumor xenograft experiments in nude mice. The related molecular mechanisms were delineated by RNA sequencing (RNA-seq), real-time polymerase chain reaction (PCR), western blotting, coimmunoprecipitation (co-IP) and plasmid transfection. RESULTS: DGT induced apoptosis and suppressed the proliferation, invasion, migration, and tumorigenicity of RCC cells. Mechanistically, yes-associated protein (YAP) signaling was inactivated, and the expression of YAP and its target genes was reduced in degalactotigonin-treated RCC cells. Additionally, DGT activated phosphorylated large tumor suppressor 1/2 (p-LATS1/2) to phosphorylate YAP, which increased YAP retention in the cytoplasm but decreased the amount of YAP that entered the nuclei of RCC cells. Moreover, DGT impaired the increased aggressive features of RCC cells induced by YAP overexpression. CONCLUSIONS: DGT is an effective therapeutic agent, which facilitates the apoptosis and inhibits the proliferation, invasion, migration, and tumorigenicity of RCC cells in a YAP-dependent manner.

11.
Chem Asian J ; 14(4): 582-591, 2019 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-30650249

RESUMEN

A cyclen-based hybrid supermolecule crystal, [(FeCl2 )(cyclen)]Cl (1), where cyclen=1,4,7,10-tetraazacyclododecane, was prepared using a liquid-liquid diffusion approach. The variable crystal structures exhibit that compound 1 belongs to an orthorhombic crystal system, Pna21 space group (point group C2V ) in the temperature range of 150-400 K. This hybrid supermolecule shows a dielectric relaxation behavior around room temperature, and the ferroelectric nature of 1 has been directly verified by hysteresis measurements. In addition, the AC (alternating current) conductivity study reveals that the 1 displays a beyond limiting behavior. These interesting findings are for the first time reported in the field of supermolecular ferroelectrics. This study may open a new way to construct supermolecular ferroelectrics and give insights into their conductor behavior.

12.
EBioMedicine ; 39: 255-264, 2019 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-30558998

RESUMEN

BACKGROUND: In the clinic, how to stratify renal cell carcinoma (RCC) patients with different risks and to accurately predict their prognostic outcome remains a crucial issue. In this study, we assessed the expression and prognostic value of gankyrin in RCC patients. METHODS: The expression of gankyrin was examined in public databases and validated in specimens from two independent centers. The clinical practice and disease correlation of gankyrin in RCC were evaluated in RCC patients, various cell lines and an orthotopic RCC model. FINDINGS: Upregulation of gankyrin expression in RCC was corroborated in two independent cohorts. High gankyrin expression positively associated with disease progression and metastasis of RCC patients. A positive correlation between gankyrin and sunitinib-resistance was also observed in RCC cell lines and in an orthotopic RCC model. Kaplan-Meier analysis revealed that patients with higher gankyrin expression presented worse prognosis of RCC patients in the two cohorts. Gankyrin served as an independent prognostic factor for RCC patients even after multivariable adjustment by clinical variables. Time-dependent AUC and Harrell's c-index analysis presented that the incorporation of the gankyrin classifier into the current clinical prognostic parameters such as TNM stage, Fuhrman nuclear grade or SSIGN score achieved a greater accuracy than without it in predicting prognosis of RCC patients. All results were confirmed in randomized training and validation sets from the two patient cohorts. INTERPRETATION: Gankyrin can serve as a reliable biomarker for disease progression and for prognosis of RCC patients. Combining gankyrin with the current clinical parameters may help patient management. FUND: National Natural Science Foundation of China (No. 81773154, 81772747 and 81301861), Medical Discipline Construction Project of Pudong New Area Commission of Health and Family Planning (PWYgf2018-03), the Shanghai Medical Guidance (Chinese and Western Medicine) Science and Technology Support Project (No. 17411960200), Outstanding Leaders Training Program of Pudong Health Bureau of Shanghai (No. PWR12016-05).


Asunto(s)
Carcinoma de Células Renales/patología , Resistencia a Antineoplásicos , Neoplasias Renales/patología , Complejo de la Endopetidasa Proteasomal/genética , Complejo de la Endopetidasa Proteasomal/metabolismo , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas/metabolismo , Regulación hacia Arriba , Animales , Biomarcadores de Tumor/genética , Biomarcadores de Tumor/metabolismo , Carcinoma de Células Renales/genética , Carcinoma de Células Renales/metabolismo , Línea Celular Tumoral , China , Progresión de la Enfermedad , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , Neoplasias Renales/genética , Neoplasias Renales/metabolismo , Masculino , Ratones , Estadificación de Neoplasias , Trasplante de Neoplasias , Pronóstico , Sunitinib/farmacología
13.
Chem Asian J ; 13(6): 656-663, 2018 Mar 16.
Artículo en Inglés | MEDLINE | ID: mdl-29356387

RESUMEN

Multifunctional materials that exhibit different physical properties in a single phase have potential for use in multifunctional devices. Herein, we reported an organic-inorganic hybrid compound [(18-crown-6)K][Fe(1)Cl(1)4 ]0.5 [Fe(2)Cl(2)4 ]0.5 (1) by incorporating KCl and FeCl3 into a 18-crown-6 molecule, which acts as a host of the six O atoms providing a lone pair of electrons to anchor the guest potassium cation, and [FeCl4 ]- as a counterion for charge balance to construct a complex salt. This salt exhibited a one-step reversible structural transformation giving two separate high and low temperature phases at 373 K, which was confirmed by systematic characterizations including differential scanning calorimetry (DSC) measurements, variable-temperature structural analyses, and dielectric, impedance, variable-temperature magnetic susceptibility measurements. Interestingly, the structural transformation was coupled to both hysteretic dielectric phase transition, conductivity switch and magnetic-phase transition at 373 K. This result gives an idea for designing a new type of phase-transition materials harboring technologically important magnetic, conductivity and dielectric properties.

14.
J Biomed Opt ; 20(11): 116004, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-26524681

RESUMEN

Optical coherence tomography angiography (Angio-OCT), mainly based on the temporal dynamics of OCT scattering signals, has found a range of potential applications in clinical and scientific research. Based on the model of random phasor sums, temporal statistics of the complex-valued OCT signals are mathematically described. Statistical distributions of the amplitude differential and complex differential Angio-OCT signals are derived. The theories are validated through the flow phantom and live animal experiments. Using the model developed, the origin of the motion contrast in Angio-OCT is mathematically explained, and the implications in the improvement of motion contrast are further discussed, including threshold determination and its residual classification error, averaging method, and scanning protocol. The proposed mathematical model of Angio-OCT signals can aid in the optimal design of the system and associated algorithms.


Asunto(s)
Velocidad del Flujo Sanguíneo/fisiología , Angiografía Cerebral/métodos , Arterias Cerebrales/fisiología , Circulación Cerebrovascular/fisiología , Interpretación Estadística de Datos , Tomografía de Coherencia Óptica/métodos , Animales , Arterias Cerebrales/anatomía & histología , Interpretación de Imagen Asistida por Computador/métodos , Ratones , Ratones Endogámicos C57BL , Movimiento (Física) , Reproducibilidad de los Resultados , Sensibilidad y Especificidad
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