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1.
Int J Legal Med ; 138(3): 961-970, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38240839

RESUMEN

This study aimed to explore and develop data mining models for adult age estimation based on CT reconstruction images from the sternum. Maximum intensity projection (MIP) images of chest CT were retrospectively collected from a modern Chinese population, and data from 2700 patients (1349 males and 1351 females) aged 20 to 70 years were obtained. A staging technique within four indicators was applied. Several data mining models were established, and mean absolute error (MAE) was the primary comparison parameter. The intraobserver and interobserver agreement levels were good. Within internal validation, the optimal data mining model obtained the lowest MAE of 9.08 in males and 10.41 in females. For the external validation (N = 200), MAEs were 7.09 in males and 7.15 in females. In conclusion, the accuracy of our model for adult age estimation was among similar studies. MIP images of the sternum could be a potential age indicator. However, it should be combined with other indicators since the accuracy level is still unsatisfactory.


Asunto(s)
Esternón , Tomografía Computarizada por Rayos X , Adulto , Masculino , Femenino , Humanos , Estudios Retrospectivos , Tomografía Computarizada por Rayos X/métodos , Esternón/diagnóstico por imagen , Minería de Datos , China
2.
J Sci Food Agric ; 104(10): 5816-5825, 2024 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-38406876

RESUMEN

BACKGROUND: The strong connection between gut microbes and human health has been confirmed by an increasing number of studies. Although probiotics have been found to relieve ulcerative colitis, the mechanism varies by the species involved. In this study, the physiological, immune and pathological factors of mice were measured and shotgun metagenomic sequencing was conducted to investigate the potential mechanisms in preventing ulcerative colitis. RESULTS: The results demonstrated that ingestion of Lactobacillus fermentum GLF-217 and Lactobacillus plantarum FLP-215 significantly alleviated ulcerative colitis induced by dextran sulfate sodium (DSS), as evidenced by the increase in body weight, food intake, water intake and colon length as well as the decrease in disease activity index, histopathological score and inflammatory factor. Both strains not only improved intestinal mucosa by increasing mucin-2 and zonula occludens-1, but also improved the immune system response by elevating interleukin-10 levels and decreasing the levels of interleukin-1ß, interleukin-6, tumor necrosis factor-α and interferon-γ. Moreover, L. fermentum GLF-217 and L. plantarum FLP-215 play a role in preventing DSS-induced colitis by regulating the structure of gut microbiota and promoting the formation of short-chain fatty acids. CONCLUSIONS: This study may provide a reference for the prevention strategy of ulcerative colitis. © 2024 Society of Chemical Industry.


Asunto(s)
Colitis Ulcerosa , Microbioma Gastrointestinal , Lactobacillus plantarum , Limosilactobacillus fermentum , Probióticos , Animales , Colitis Ulcerosa/microbiología , Colitis Ulcerosa/prevención & control , Colitis Ulcerosa/inducido químicamente , Colitis Ulcerosa/inmunología , Ratones , Probióticos/administración & dosificación , Probióticos/farmacología , Masculino , Humanos , Sulfato de Dextran/efectos adversos , Colon/microbiología , Colon/inmunología , Colon/patología , Mucosa Intestinal/microbiología , Mucosa Intestinal/inmunología , Mucosa Intestinal/metabolismo , Ratones Endogámicos C57BL , Interleucina-10/genética , Interleucina-10/metabolismo , Interleucina-1beta/genética , Interleucina-1beta/metabolismo , Interleucina-1beta/inmunología , Bacterias/clasificación , Bacterias/genética , Bacterias/aislamiento & purificación , Mucina 2/metabolismo , Mucina 2/genética , Interleucina-6/genética , Interleucina-6/metabolismo , Interleucina-6/inmunología , Factor de Necrosis Tumoral alfa/metabolismo , Factor de Necrosis Tumoral alfa/genética , Factor de Necrosis Tumoral alfa/inmunología , Interferón gamma/metabolismo , Interferón gamma/genética , Interferón gamma/inmunología , Proteína de la Zonula Occludens-1/metabolismo , Proteína de la Zonula Occludens-1/genética , Modelos Animales de Enfermedad
3.
Eur Radiol ; 33(11): 7519-7529, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37231070

RESUMEN

OBJECTIVE: Adult age estimation (AAE) is a challenging task. Deep learning (DL) could be a supportive tool. This study aimed to develop DL models for AAE based on CT images and compare their performance to the manual visual scoring method. METHODS: Chest CT were reconstructed using volume rendering (VR) and maximum intensity projection (MIP) separately. Retrospective data of 2500 patients aged 20.00-69.99 years were obtained. The cohort was split into training (80%) and validation (20%) sets. Additional independent data from 200 patients were used as the test set and external validation set. Different modality DL models were developed accordingly. Comparisons were hierarchically performed by VR versus MIP, single-modality versus multi-modality, and DL versus manual method. Mean absolute error (MAE) was the primary parameter of comparison. RESULTS: A total of 2700 patients (mean age = 45.24 years ± 14.03 [SD]) were evaluated. Of single-modality models, MAEs yielded by VR were lower than MIP. Multi-modality models generally yielded lower MAEs than the optimal single-modality model. The best-performing multi-modality model obtained the lowest MAEs of 3.78 in males and 3.40 in females. On the test set, DL achieved MAEs of 3.78 in males and 3.92 in females, which were far better than the MAEs of 8.90 and 6.42 respectively, for the manual method. For the external validation, MAEs were 6.05 in males and 6.68 in females for DL, and 6.93 and 8.28 for the manual method. CONCLUSIONS: DL demonstrated better performance than the manual method in AAE based on CT reconstruction of the costal cartilage. CLINICAL RELEVANCE STATEMENT: Aging leads to diseases, functional performance deterioration, and both physical and physiological damage over time. Accurate AAE may aid in diagnosing the personalization of aging processes. KEY POINTS: • VR-based DL models outperformed MIP-based models with lower MAEs and higher R2 values. • All multi-modality DL models showed better performance than single-modality models in adult age estimation. • DL models achieved a better performance than expert assessments.


Asunto(s)
Cartílago Costal , Aprendizaje Profundo , Masculino , Femenino , Humanos , Adulto , Persona de Mediana Edad , Estudios Retrospectivos , Tomografía Computarizada por Rayos X/métodos , Tórax
4.
Int J Legal Med ; 137(5): 1527-1533, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37493764

RESUMEN

Radiology plays a crucial role in forensic anthropology for age estimation. However, most studies rely on morphological methods. This study aims to investigate the feasibility of using pubic bone mineral density (BMD) as a new age estimation method in the Chinese population. 468 pubic bone CT scans from living individuals in a Chinese hospital aged 18 to 87 years old were used to measure pubic BMD. The BMD of the bilateral pubic bone was measured using the Mimics software on cross-sectional CT images and the mean BMD of the bilateral pubic bone was also calculated. Regression analysis was performed to assess the correlation between pubic BMD and chronological age and to develop mathematical models for age estimation. We evaluated the accuracy of the best regression model using an independent validation sample by calculating the mean absolute error (MAE). Among all established models, the cubic regression model had the highest R2 value in both genders, with R2 = 0.550 for males and R2 = 0.634 for females. The results of the best model test showed that the MAE for predicting age using pubic BMD was 8.66 years in males and 7.69 years in females. This study highlights the potential of pubic BMD as a useful objective indicator for adult age estimation and could be used as an alternative in forensic practice when other better indicators are lacking.

5.
J Immunol ; 206(5): 1088-1101, 2021 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-33495235

RESUMEN

The skin of vertebrates is the outermost organ of the body and serves as the first line of defense against external aggressions. In contrast to mammalian skin, that of teleost fish lacks keratinization and has evolved to operate as a mucosal surface containing a skin-associated lymphoid tissue (SALT). Thus far, IgT representing the prevalent Ig in SALT have only been reported upon infection with a parasite. However, very little is known about the types of B cells and Igs responding to bacterial infection in the teleost skin mucosa, as well as the inductive or effector role of the SALT in such responses. To address these questions, in this study, we analyzed the immune response of trout skin upon infection with one of the most widespread fish skin bacterial pathogens, Flavobacterium columnare This pathogen induced strong skin innate immune and inflammatory responses at the initial phases of infection. More critically, we found that the skin mucus of fish having survived the infection contained significant IgT- but not IgM- or IgD-specific titers against the bacteria. Moreover, we demonstrate the local proliferation and production of IgT+ B cells and specific IgT titers, respectively, within the SALT upon bacterial infection. Thus, our findings represent the first demonstration that IgT is the main Ig isotype induced by the skin mucosa upon bacterial infection and that, because of the large surface of the skin, its SALT probably represents a prominent IgT-inductive site in fish.


Asunto(s)
Linfocitos B/inmunología , Infecciones por Flavobacteriaceae/inmunología , Inmunidad Mucosa/inmunología , Inmunoglobulinas/inmunología , Membrana Mucosa/inmunología , Oncorhynchus mykiss/inmunología , Piel/inmunología , Animales , Proliferación Celular/fisiología , Enfermedades de los Peces/inmunología , Enfermedades de los Peces/microbiología , Proteínas de Peces , Infecciones por Flavobacteriaceae/microbiología , Flavobacterium/inmunología , Inmunidad Innata/inmunología , Isotipos de Inmunoglobulinas/inmunología , Inflamación/inmunología , Inflamación/microbiología , Tejido Linfoide/inmunología , Membrana Mucosa/microbiología , Oncorhynchus mykiss/microbiología , Piel/microbiología
6.
Chaos ; 33(8)2023 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-37549117

RESUMEN

Synchronization is one of the key issues in three-phase AC power systems. Its characteristics have been dramatically changed with the large-scale integration of power-electronic-based renewable energy, mainly including a permanent magnetic synchronous generator (PMSG) and a double-fed induction generator (DFIG) for wind energy and a photovoltaic (PV) generator for solar energy. In this paper, we review recent progresses on the synchronization stability and multi-timescale properties of the renewable-dominated power system (RDPS), from nodes and network perspectives. All PMSG, DFIG, and PV are studied. In the traditional synchronous generator (SG) dominated power system, its dynamics can be described by the differential-algebraic equations (DAEs), where the dynamic apparatuses are modeled by differential equations and the stationary networks are described by algebraic equations. Unlike the single electromechanical timescale and DAE description for the SG-dominated power system, the RDPS dynamics should be described by the multiscale dynamics of both nodes and networks. For three different timescales, including the AC current control, DC voltage control, and rotor electromechanical timescales, their corresponding models are well established. In addition, for the multiscale network dynamics, the dynamical network within the AC current control timescale, which should be described by differential equations, can also be simplified as algebraic equations. Thus, the RDPS dynamics can be put into a similar DAE diagram for each timescale to the traditional power system dynamics, with which most of power electrical engineers are familiar. It is also found that the phase-locked loop for synchronization plays a crucial role in the whole system dynamics. The differences in the synchronization and multiscale characteristics between the traditional power system and the RDPS are well uncovered and summarized. Therefore, the merit of this paper is to establish a basic physical picture for the stability mechanism in the RDPS, which still lacks systematic studies and is controversial in the field of electrical power engineering.

7.
Chaos ; 33(3): 032102, 2023 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-37003797

RESUMEN

Synchronization stability is one of central problems in power systems, and it is becoming much more complicated with the high penetration of renewable energy and power electronics devices. In this paper, we review recent work by several nonlinear models for renewable-dominated power systems in terms of multiple timescales, in particular, grid-tied converters within the DC voltage timescale. For the simplest model, a second-order differential equations called the generalized swing equation by considering only the phase-locked loop (PLL) is obtained, which shows a similar form with the well-known swing equation for a synchronous generator in the traditional power systems. With more outer controllers included, fourth-order and fifth-order models can be obtained. The fourth-order model is called the extended generalized swing equation, exhibiting the combined function of grid synchronization and active power balance on the DC capacitor. In addition, a nonlinear model for a two coupled converter system is given. Based on these studies, we find that the PLL plays a key role in synchronization stability. In summary, the value of this paper is to clarify the key concept of the synchronization stability in renewable-dominated power systems based on different nonlinear models, which still lacks systematic studies and is controversial in the field of electrical power engineering. Meanwhile, it clearly uncovers that the synchronization stability of converters has its root in the phase synchronization concept in nonlinear sciences.

8.
Phytother Res ; 37(6): 2454-2471, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-36772986

RESUMEN

Mitochondrial inflammation triggered by abnormal mitochondrial division and regulated by the Drp1/HK1/NLRP3 pathway is correlated with the progression of aging-associated cognitive impairment (AACI). Alpinetin is a novel flavonoid derived from Zingiberaceae that has many bioactivities such as antiinflammation and anti-oxidation. However, whether alpinetin alleviates AACI by suppressing Drp1/HK1/NLRP3 pathway-inhibited mitochondrial inflammation is still unknown. In the present study, D-galactose (D-gal)-induced aging mice and BV-2 cells were used, and the effects of alpinetin on learning and memory function, neuroprotection and activation of the Drp1/HK1/NLRP3 pathway were investigated. Our data indicated that alpinetin significantly alleviated cognitive dysfunction and neuronal damage in the CA1 and CA3 regions of D-gal-treated mice. Moreover, D-gal-induced microglial activation was markedly reduced by alpinetin by inhibiting the Drp1/HK1/NLRP3 pathway-suppressed mitochondrial inflammation, down-regulating the levels of p-Drp1 (s616), VDAC, NLRP3, ASC, Cleaved-caspase 1, IL-18, and IL-1ß, and up-regulating the expression of HK1. Furthermore, after Drp1 inhibition by Mdivi-1 in vitro, the inhibitory effect of alpinetin on Drp1/HK1/NLRP3 pathway was more evident. In summary, the current results implied that alpinetin attenuated aging-related cognitive deficits by inhibiting the Drp1/HK1/NLRP3 pathway and suppressing mitochondrial inflammation, suggesting that the inhibition of the Drp1/HK1/NLRP3 pathway is one of the mechanisms by which alpinetin attenuates AACI.


Asunto(s)
Disfunción Cognitiva , Proteína con Dominio Pirina 3 de la Familia NLR , Ratones , Animales , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , Inflamación/tratamiento farmacológico , Envejecimiento , Galactosa/efectos adversos , Disfunción Cognitiva/tratamiento farmacológico
9.
Int J Legal Med ; 136(3): 841-852, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-35258670

RESUMEN

OBJECTIVES: To assess the performance of knee MRI for forensic age prediction and classification for 12-, 14-, 16-, and 18-year thresholds. METHODS: The ossification stages of distal femoral epiphyses and proximal tibial epiphyses were assessed using an integrated staging system by Schmeling et al. and Kellinghaus et al. for knee 3.0T MRI with T1-weighted turbo spin-echo (T1-TSE) in sagittal orientation among 852 Chinese Han individuals (483 males and 369 females) aged 7-30 years. Regression models for age prediction were constructed and their performances were evaluated based on mean absolute deviation (MAD) values. In addition, the performances of age classification were assessed using receiver operating characteristic (ROC) analyses. RESULTS: The intra- and inter-observer agreement levels were very good (κ > 0.80). The complete fusion of those two types of epiphyses took place before 18.0 years in our study participants. The minimum MAD values were 2.51 years (distal femur) and 2.69 years (proximal tibia) in males, and 2.75 years (distal femur) and 2.87 years (proximal tibia) in females. The specificity values of constructed prediction models were all above 90% for the 12-, 14-, and 16-year thresholds, compared to the 74.8-84.6% for the 18-year threshold. Better performances of age prediction and classification were observed in males by distal femoral epiphyses. CONCLUSIONS: Ossification stages via 3.0T MRI of the knee with T1-TSE sequence using an integrated staging system could be a reliable noninvasive method for age prediction or for age classification for 12-, 14-, and 16-year thresholds, especially in males by distal femoral epiphyses. However, assessments based on the full bony fusion of the distal femoral epiphysis and proximal tibial epiphysis seemed not reliable for age classification for the 18-year threshold in the Chinese Han population.


Asunto(s)
Determinación de la Edad por el Esqueleto , Epífisis , Determinación de la Edad por el Esqueleto/métodos , China , Epífisis/diagnóstico por imagen , Femenino , Fémur/diagnóstico por imagen , Humanos , Imagen por Resonancia Magnética/métodos , Masculino , Osteogénesis , Tibia/diagnóstico por imagen
10.
J Headache Pain ; 23(1): 1, 2022 Jan 03.
Artículo en Inglés | MEDLINE | ID: mdl-34979902

RESUMEN

BACKGROUND: Chronic migraine places a disabling burden on patients, which is extensively modeled by the nitroglycerin (NTG)-treated animal model. Although the NF-κB pathway is involved in an increase in CGRP levels and activation of the trigeminal system in the NTG model, the relationship between NTG and neuroinflammation remains unclear. This study aimed to optimize a chronic NTG rat model with hyperalgesia and the ethological capacity for estimating migraine therapies and to further explore the underlying mechanism of NTG-induced migraine. METHODS: Rats were administered different doses of NTG s.c. daily or every 2 d; 30 min and 2 h later, the mechanical threshold was tested. After 9 d, the rats were injected with EB or Cy5.5 for the permeability assay. The other animals were sacrificed, and then, brainstem and caudal trigeminal ganglion were removed to test CGRP, c-Fos and NOS activity; Cytokines levels in the tissue and serum were measured by ELISA; and NF-κB pathway and blood-brain barrier (BBB)-related indicators were analyzed using western blotting. Immunohistochemistry was performed to observe microglial polarization and IL-17A+ T cell migration in the medulla oblongata. RESULTS: NTG (10 mg/kg, s.c., every 2 d for a total of 5 injections) was the optimal condition, resulting in progressive hyperalgesia and migraine behavior. TNC neuroinflammation with increases in cytokines, CGRP and c-Fos and activation of the NF-κB pathway was observed, and these changes were alleviated by ibuprofen. Furthermore, NTG administration increased BBB permeability by altering the levels functional proteins (RAGE, LRP1, AQP4 and MFSD2A) and structural proteins (ZO-1, Occludin and VE-cadherin-2) to increase peripheral IL-17A permeation into the medulla oblongata, activating microglia and neuroinflammation, and eventually causing hyperalgesia and migraine attack. CONCLUSIONS: This study confirmed that NTG (10 mg/kg, s.c., every 2 d for a total of 5 injections) was the optimal condition to provoke migraine, resulting in mechanical hyperalgesia and observable migraine-like behavior. Furthermore, IL-17A crossed the blood-brain barrier into the medulla oblongata, triggering TNC activation through microglia-mediated neuroinflammation. This process was a novel mechanism in NTG-induced chronic migraine, suggesting that IL-17A might be a novel target in the treatment of migraine.


Asunto(s)
Trastornos Migrañosos , Nitroglicerina , Animales , Barrera Hematoencefálica , Modelos Animales de Enfermedad , Humanos , Interleucina-17 , Trastornos Migrañosos/inducido químicamente , Enfermedades Neuroinflamatorias , Nitroglicerina/toxicidad , Ratas
11.
Fish Shellfish Immunol ; 118: 385-395, 2021 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-34563671

RESUMEN

CD79a and CD79b heterodimers are important components that consist of B cell receptor compound, which play a crucial role in transduction activation signal of the antigen binding BCR, and B cell development and antibody production. In order to investigate the characters and potential functions of CD79a and CD79b in rainbow trout (Oncorhynchus mykiss), we firstly cloned and analyzed the expression of CD79a and CD79b and found that the cDNA sequences of CD79a and CD79b both contained open reading frame of 711 and 645 bp in length for encoding the protein of 237 and 215 amino acid residues, respectively. The predicted amino acid sequences from trout were highly conserved with those of other teleost fishes in structure. Phylogenetic tree was constructed to analyze the evolutionary relationship between the trout and other known species, the result indicated that CD79a and CD79b of trout clustered at high bootstrap values with Salmo salar. Moreover, three trout infection models with F. columnare G4, I. multifiliis and infectious hematopoietic necrosis virus (IHNV) were constructed, which resulted in morphological changes and serious lesions in skin and gills. Importantly, the high expression of CD79a and CD79b occurred in skin, gills, and followed by head kidney in response to bacterial, parasitic, and viral infection, as its expression was closely related to that of Igs. Our findings indicated that CD79a and CD79b play vital roles in both systemic and mucosal immune responses of rainbow trout during bacterial, parasitic, and viral infection, which will contribute to explore the roles of CD79 subunits in B cell signaling during ontogeny and disease.


Asunto(s)
Enfermedades de los Peces , Oncorhynchus mykiss , Parásitos , Virosis , Animales , Bacterias , Clonación Molecular , Oncorhynchus mykiss/genética , Filogenia
12.
Zhonghua Nan Ke Xue ; 27(4): 330-333, 2021 Apr.
Artículo en Zh | MEDLINE | ID: mdl-34914216

RESUMEN

OBJECTIVE: To investigate the clinical effect of tadalafil combined with behavioral therapy and psychological counseling in the treatment of erectile dysfunction (ED). METHODS: We collected the clinical data on 338 cases of ED treated in our andrology clinic with tadalafil combined with behavioral therapy and psychological counseling (the trial group, n = 159) or with tadalafil alone (the control group, n = 179) from January to December 2019. Using chief complaints scores as the main observation indexes, we evaluated the subjective feelings and objective symptoms of the patients during their sexual life. RESULTS: After treatment, the patients in the trial group, compared with the controls, showed significantly lower chief complaints scores (1.96 ± 1.38 vs 2.73 ± 1.80, P < 0.01) and higher satisfaction with the therapeutic effect (67.9% vs 47.5%, P < 0.01). No statistically significant difference was observed in the IIEF-5 scores between the two groups before and after treatment. CONCLUSIONS: Tadalafil combined with behavior therapy and psychological counseling is superior to oral tadalafil alone in the treatment of ED, which affords greater satisfaction with the therapeutic effect, higher quality of sexual life, and better relationship between the partners.


Asunto(s)
Disfunción Eréctil , Terapia Conductista , Terapia Combinada , Consejo , Disfunción Eréctil/tratamiento farmacológico , Disfunción Eréctil/terapia , Humanos , Masculino , Tadalafilo/uso terapéutico
13.
J Am Chem Soc ; 142(18): 8464-8472, 2020 05 06.
Artículo en Inglés | MEDLINE | ID: mdl-32275405

RESUMEN

Gregatin A (1) is a fungal polyketide featuring an alkylated furanone core, but the biosynthetic mechanism to furnish the intriguing molecular skeleton has yet to be elucidated. Herein, we have identified the biosynthetic gene cluster of gregatin A (1) in Penicillium sp. sh18 and investigated the mechanism that produces the intriguing structure of 1 by in vivo and in vitro reconstitution of its biosynthesis. Our study established the biosynthetic route leading to 1 and illuminated that 1 is generated by the fusion of two different polyketide chains, which are, amazingly, synthesized by a single polyketide synthase GrgA with the aid of a trans-acting enoylreductase GrgB. Chain fusion, as well as chain hydrolysis, is catalyzed by an α/ß hydrolase, GrgF, hybridizing the C11 and C4 carbon chains by Claisen condensation. Finally, structural analysis and mutational experiments using GrgF provided insight into how the enzyme facilitates the unusual chain-fusing reaction. In unraveling a new biosynthetic strategy involving a bifunctional PKS and a polyketide fusing enzyme, our study expands our knowledge concerning fungal polyketide biosynthesis.


Asunto(s)
Policétidos/metabolismo , Estructura Molecular , Sintasas Poliquetidas/química , Sintasas Poliquetidas/metabolismo , Policétidos/química , Estereoisomerismo
14.
Int J Legal Med ; 134(5): 1843-1852, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32594229

RESUMEN

OBJECTIVES: To expand the database on magnetic resonance imaging (MRI) analysis of distal tibial and calcaneal epiphyses as proposed by Saint-Martin et al. and investigate a more elaborate staging technique to establish regression models for age estimation in a modern Chinese Han population. MATERIALS AND METHODS: T1-weighted ankle MRIs were retrospectively collected from April 2008 to July 2019, and data from 590 individuals (372 males and 218 females; aged from 8 to 25 years old) were obtained. One-sided sagittal images were assessed because data from both sides were considered coincidental, as no significant differences were found (P > 0.05). Three-stage and six-stage staging techniques were applied separately and subsequently compared. A subset was re-assessed a second time and by a different observer. Regression models were established accordingly. RESULTS: Our results showed very good repeatability and consistency of two staging techniques (all Cohen's kappa values were more than 0.8). By comparison, the values of the coefficient of determination (R2) of the six-stage technique were generally higher than those of the three-stage technique. Compared with the distal tibia and two ankle bones combined, the calcaneus decreased the mean absolute deviation (MAD) with the six-stage technique. In males, incorporating only the calcaneus resulted in a MAD of 2.15 years, with correct classification rates of 87.5% adults and 50.0% among minors. In females, the corresponding results were 1.67 years, 100.0%, and 44.4%, respectively. CONCLUSIONS: The six-stage technique may outperform the three-stage technique in MRI analysis of ankle bones for age estimation, while age estimation based on the calcaneus may perform better than that based on the distal tibia or both ankle bones in a modern Chinese Han population.


Asunto(s)
Determinación de la Edad por el Esqueleto/métodos , Articulación del Tobillo/diagnóstico por imagen , Calcáneo/diagnóstico por imagen , Epífisis/diagnóstico por imagen , Adolescente , Articulación del Tobillo/crecimiento & desarrollo , Pueblo Asiatico/etnología , Calcáneo/crecimiento & desarrollo , Niño , Epífisis/crecimiento & desarrollo , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Análisis de Regresión , Reproducibilidad de los Resultados , Adulto Joven
15.
Chaos ; 30(1): 013110, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-32013499

RESUMEN

The swing equation plays a central role in the model and analysis of power system dynamics, including small-signal stability and transient stability. As it has the same form as that in a variety of different disciplines, such as the forced pendulum in mechanics, the classical mechanistic description of superconducting Josephson junctions in physics, and the classical second-order phase-locking loop in electronics, it has aroused general interest in science and engineering. In this paper, its approximate solution of the limit cycle is obtained by means of the incremental harmonic balance (IHB) method. It is found that the trouble of a more distorted limit cycle when the parameters are closer to the homoclinic bifurcation curve can be easily solved by incorporating higher order harmonics in the IHB method. In this way, we can predict the homoclinic bifurcation curve perfectly. In addition, the method is extended to study a generalized swing equation including excitation voltage dynamics.

16.
Chaos ; 27(8): 083116, 2017 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-28863492

RESUMEN

Power grids and their properties have been studied broadly in many aspects. In this paper, we propose a novel concept, power-flow-based power grid, as a typical power-functional network, based on the calculation of power flow distribution from power electrical engineering. We compare it with structural networks based on the shortest path length and effective networks based on the effective electrical distance and study the relationship among these three kinds of networks. We find that they have roughly positive correlations with each other, indicating that in general any close nodes in the topological structure are actually connected in function. However, we do observe some counter-examples that two close nodes in a structural network can have a long distance in a power-functional network, namely, two physically connected nodes can actually be separated in function. In addition, we find that power grids in the structural network tend to be heterogeneous, whereas those in the effective and power-functional networks tend to be homogeneous. These findings are expected to be significant not only for power grids but also for various other complex networks.

17.
Chaos ; 27(11): 114303, 2017 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-29195315

RESUMEN

We numerically investigate the impacts of both propagation and processing delays on the emergences of amplitude death (AD) and oscillation death (OD) in one system of two Stuart-Landau oscillators with symmetry-breaking coupling. In either the absence of or the presence of propagation delay, the processing delay destabilizes both AD and OD by revoking the stability of the stable homogenous and inhomogenous steady states. In the AD to OD transition, the processing delay destabilizes first OD from large values of coupling strength until its stable regime completely disappears and then AD from both the upper and lower bounds of the stable coupling interval. Our numerical study sheds new insight lights on the understanding of nontrivial effects of time delays on dynamic activity of coupled nonlinear systems.

18.
Chaos ; 27(12): 126702, 2017 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-29289042

RESUMEN

It has been generally believed that both time delay and network structure could play a crucial role in determining collective dynamical behaviors in complex systems. In this work, we study the influence of coupling strength, time delay, and network topology on synchronization behavior in delay-coupled networks of chaotic pendulums. Interestingly, we find that the threshold value of the coupling strength for complete synchronization in such networks strongly depends on the time delay in the coupling, but appears to be insensitive to the network structure. This lack of sensitivity was numerically tested in several typical regular networks, such as different locally and globally coupled ones as well as in several complex networks, such as small-world and scale-free networks. Furthermore, we find that the emergence of a synchronous periodic state induced by time delay is of key importance for the complete synchronization.

20.
Chaos ; 24(1): 013104, 2014 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-24697366

RESUMEN

Clustering phase synchronization (CPS) is a common scenario to the global phase synchronization of coupled dynamical systems. In this work, a novel scenario, the non-clustering phase synchronization (NPS), is reported. It is found that coupled systems do not transit to the global synchronization until a certain sufficiently large coupling is attained, and there is no clustering prior to the global synchronization. To reveal the relationship between CPS and NPS, we further analyze the noise effect on coupled phase oscillators and find that the coupled oscillator system can change from CPS to NPS with the increase of noise intensity or system disorder. These findings are expected to shed light on the mechanism of various intriguing self-organized behaviors in coupled systems.

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