Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 11 de 11
Filtrar
1.
J Therm Biol ; 112: 103447, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36796902

RESUMO

Temperature step change is the typical transient thermal environment. The purpose of this study was to explore the association of subjective and objective parameters in a step-change environment, including thermal sensation vote (TSV), thermal comfort vote (TCV), mean skin temperature (MST) and endogenous dopamine (DA). Three temperature step changes defined as I3 (15 °C-18 °C to 15 °C), I9 (15 °C-24 °C to 15 °C) and I15 (15 °C-30 °C to 15 °C) were designed for this experiment. Eight male and eight female healthy subjects who participated in the experiment reported thermal perception (TSV and TCV). Skin temperatures of six body parts and DA were measured. Results show that the inverted U-shaped in TSV and TCV was deviated by seasonal factors of the experiment. The deviation direction of TSV in winter was to the warm sensation side, which was opposite to the inherent cold and hot impression of people in winter and summer. The association between dimensionless dopamine (DA*), TSV and MST were described as follows: DA* was the U-shaped change with exposure times when MST was not greater than 31 °C, and TSV was at -2 and -1, and DA* increased with exposure times when MST was greater than 31 °C, and TSV was at 0, 1 and 2. The changes in the body heat storage and autonomous thermal regulation under temperature step changes may potentially be related to the concentration of DA. The human state on thermal nonequilibrium and stronger thermal regulation would correspond to a higher concentration of DA. This work is conducive to exploring the human regulation mechanism in a transient environment.


Assuntos
Dopamina , Temperatura Cutânea , Humanos , Masculino , Feminino , Estações do Ano , Temperatura Baixa , Temperatura Alta , Sensação Térmica/fisiologia , Temperatura
2.
IEEE J Biomed Health Inform ; 28(7): 4157-4169, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38662560

RESUMO

Multi-Object tracking in real world environments is a tough problem, especially for cell morphogenesis with division. Most cell tracking methods are hard to achieve reliable mitosis detection, efficient inter-frame matching, and accurate state estimation simultaneously within a unified tracking framework. In this paper, we propose a novel unified framework that leverages a spatio-temporal ant colony evolutionary algorithm to track cells amidst mitosis under measurement uncertainty. Each Bernoulli ant colony representing a migrating cell is able to capture the occurrence of mitosis through the proposed Isolation Random Forest (IRF)-assisted temporal mitosis detection algorithm with the assumption that mitotic cells exhibit unique spatio-temporal features different from non-mitotic ones. Guided by prediction of a division event, multiple ant colonies evolve between consecutive frames according to an augmented assignment matrix solved by the extended Hungarian method. To handle dense cell populations, an efficient group partition between cells and measurements is exploited, which enables multiple assignment tasks to be executed in parallel with a reduction in matrix dimension. After inter-frame traversing, the ant colony transitions to a foraging stage in which it begins approximating the Bernoulli parameter to estimate cell state by iteratively updating its pheromone field. Experiments on multi-cell tracking in the presence of cell mitosis and morphological changes are conducted, and the results demonstrate that the proposed method outperforms state-of-the-art approaches, striking a balance between accuracy and computational efficiency.


Assuntos
Algoritmos , Rastreamento de Células , Imagem com Lapso de Tempo , Rastreamento de Células/métodos , Imagem com Lapso de Tempo/métodos , Animais , Mitose/fisiologia , Humanos , Processamento de Imagem Assistida por Computador/métodos , Formigas/fisiologia , Formigas/citologia , Algoritmo Florestas Aleatórias
3.
J Colloid Interface Sci ; 625: 664-679, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35764046

RESUMO

A 2D/2D BiOIO3/BiOBr Z-scheme heterostructure was firstly synthesized by a simple one-pot hydrothermal process and it was used to effectively remove rhodamine B under irradiation of Xe and LED light. The BB-15 heterostructure has an optimal apparent rate constant k of 0.046 min-1 (0.17 min-1), which is ∼6.2 (89.7) and 3.5 (3.5) times that of BiOIO3 and BiOBr under the irradiation of Xe light (LED light). The enhanced photocatalytic activity can be attributed to the following points: (1) the face-to-face and tight contact in 2D/2D BiOIO3/BiOBr heterostructures provides more migration channels for photogenerated carriers which facilitates the transfer and separation of photogenerated carriers; (2) the Z-scheme photocarrier transport path not only hastens the separation and transfer efficiency of photocarriers in space but also maintains a robust redox capacity; (3) the presence of IO3-/I- redox couple and built-in electric field further encourage the separation and transfer of photocarriers and enhance the photocatalytic activity of the composite. And the O2-, h+, and OH are active species, which are responsible for the photodegrade process of RhB under irradiation of Xe light. This study provided an easy and reliable strategy to design and prepare an efficient bismuth-containing heterojunction, the characterization and evaluation experiment results proved its effectiveness for solar utilization and environmental purification.

4.
Int J Psychophysiol ; 181: 141-149, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36108800

RESUMO

Previous studies have shown that the perception of ambiguous facial expressions for individuals with social anxiety was influenced by the affective verbal context. However, it is still unknown how emotional facial expressions are perceived by individuals with social anxiety in the context of the verbal context. In this study, we used event-related potentials (ERPs) technology to examine how individuals with social anxiety perceive emotional facial expressions in positive and negative contexts. The results showed that: (1) Within the negative verbal contexts, the amplitude of P1 induced by facial expressions in the social anxiety group was significantly higher than that induced by the healthy control group; The N170 amplitude induced by facial expressions in social anxiety group was less negative than that in the healthy control group, and was not affected by the context. (2) The social anxiety group had significantly higher LPP in negative contexts elicited by angry expressions than by happy expressions. This study proved that the perception of emotional facial expressions was influenced by top-down information in the early and late stages of visual perception for individuals with social anxiety.


Assuntos
Eletroencefalografia , Expressão Facial , Ansiedade , Eletroencefalografia/métodos , Emoções/fisiologia , Potenciais Evocados/fisiologia , Humanos , Percepção Social , Percepção Visual
5.
IEEE J Biomed Health Inform ; 25(6): 2338-2349, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33079687

RESUMO

In this paper, we use an ant colony heuristic method to tackle the integration of data association and state estimation in the presence of cell mitosis, morphological change and uncertainty of measurement. Our approach first models the scouting behavior of an unlabeled ant colony as a chaotic process to generate a set of cell candidates in the current frame, then a labeled ant colony foraging process is modeled to construct an interframe matching between previously estimated cell states and current cell candidates through minimizing the optimal sub-pattern assignment metric for track (OSPA-T). The states of cells in the current frame are finally estimated using labeled ant colonies via a multi-Bernoulli parameter set approximated by individual food pheromone fields and heuristic information within the same region of support, the resulting trail pheromone fields over frames constitutes the cell lineage trees of the tracks. A four-stage track recovery strategy is proposed to monitor the history of all established tracks to reconstruct broken tracks in a computationally economic way. The labeling method used in this work is an improvement on previous techniques. The method has been evaluated on publicly available, challenging cell image sequences, and a satisfied performance improvement is achieved in contrast to the state-of-the-art methods.


Assuntos
Algoritmos , Feromônios , Ciclo Celular
6.
IEEE/ACM Trans Comput Biol Bioinform ; 18(5): 1850-1863, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-31751247

RESUMO

In this article, we take as inspiration the labor division into scouts and workers in an ant colony and propose a novel approach for automated cell tracking in the framework of multi-Bernoulli random finite sets. To approximate the Bernoulli parameter sets, we first define an existence probability of an ant colony as well as its discrete density distribution. During foraging, the behavior of scouts is modeled as a chaotic movement to produce a set of potential candidates. Afterwards, a group of workers, i.e., a worker ant colony, is recruited for each candidate, which then embark on gathering heuristic information in a self-organized way. Finally, the pheromone field is formed by the corresponding worker ant colony, from which the Bernoulli parameter is derived and the state of the cell is estimated accordingly to be associated with the existing tracks. Performance comparisons with other previous approaches are conducted on both simulated and real cell image sequences and show the superiority of this algorithm.


Assuntos
Rastreamento de Células/métodos , Biologia Computacional/métodos , Modelos Biológicos , Algoritmos , Animais , Formigas , Teorema de Bayes , Comportamento Animal , Feromônios
7.
Front Vet Sci ; 8: 745078, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34631866

RESUMO

Liver injury threatens the overall health of an organism, as it is the core organ of the animal body. Liver metabolism is affected by numerous factors, with dietary energy level being a crucial one. Therefore, the present study aimed to evaluate hepatic injury and to describe its metabolic mechanism in ruminants fed diets with different dietary energy levels. A total of 25 Yunnan semi-fine wool sheep were fed diets with five dietary metabolic energy levels and were randomly assigned to five groups as follows: low energy (LE), medium-low energy (MLE), medium energy (ME), medium-high energy (MHE), and high energy (HE). The results revealed that the average optical density (AOD) of lipid droplets in the LE, MLE, and HE groups was higher than that in the ME and MHE groups. The enzyme activity of alanine aminotransferase (ALT) was the lowest in the ME group. An increase in dietary energy level promoted the superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity and altered the malondialdehyde (MDA) and protein carbonyl (PCO) concentration quadratically. In addition, both high and low dietary energy levels upregulated the mRNA abundance of proinflammatory cytokine interleukin (IL)-1ß, nuclear factor-kappa B (NF-κB), and tumor necrosis factor (TNF)-α. Metabonomic analysis revealed that 142, 77, 65, and 108 differential metabolites were detected in the LE, MLE, MHE, and HE groups, compared with ME group respectively. These metabolites were involved in various biochemical pathways, such as glycolipid, bile acid, and lipid metabolism. In conclusion, both high and low dietary energy levels caused hepatic injury. Section staining and metabonomic results revealed that hepatic injury might be caused by altered metabolism and lipid accumulation induced by lipid mobilization.

8.
IEEE J Biomed Health Inform ; 24(6): 1703-1716, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-31670688

RESUMO

The analysis of the dynamic behavior of cells in time-lapse microscopy sequences requires the development of reliable and automatic tracking methods capable of estimating individual cell states and delineating the lineage trees corresponding to the tracks. In this paper, we propose a novel approach, i.e., an ant colony inspired multi-Bernoulli filter, to handle the tracking of a collection of cells within which mitosis, morphological change and erratic dynamics occur. The proposed technique treats each ant colony as an independent one in an ant society, and the existence probability of an ant colony and its density distribution approximation are derived from the individual pheromone field and the corresponding heuristic information for the approximation to the multi-Bernoulli parameters. To effectively guide ant foraging between consecutive frames, a dual prediction mechanism is proposed for the ant colony and its pheromone field. The algorithm performance is tested on challenging datasets with varying population density, frequent cell mitosis and uneven motion over time, demonstrating that the algorithm outperforms recently reported approaches.


Assuntos
Algoritmos , Rastreamento de Células/métodos , Microscopia/métodos , Imagem com Lapso de Tempo/métodos , Linhagem Celular , Movimento Celular/fisiologia , Humanos , Mitose/fisiologia , Modelos Biológicos
9.
J Healthc Eng ; 2017: 7406896, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29065639

RESUMO

Base scale entropy analysis (BSEA) is a nonlinear method to analyze heart rate variability (HRV) signal. However, the time consumption of BSEA is too long, and it is unknown whether the BSEA is suitable for analyzing pulse rate variability (PRV) signal. Therefore, we proposed a method named sliding window iterative base scale entropy analysis (SWIBSEA) by combining BSEA and sliding window iterative theory. The blood pressure signals of healthy young and old subjects are chosen from the authoritative international database MIT/PhysioNet/Fantasia to generate PRV signals as the experimental data. Then, the BSEA and the SWIBSEA are used to analyze the experimental data; the results show that the SWIBSEA reduces the time consumption and the buffer cache space while it gets the same entropy as BSEA. Meanwhile, the changes of base scale entropy (BSE) for healthy young and old subjects are the same as that of HRV signal. Therefore, the SWIBSEA can be used for deriving some information from long-term and short-term PRV signals in real time, which has the potential for dynamic PRV signal analysis in some portable and wearable medical devices.


Assuntos
Pressão Sanguínea , Eletrocardiografia/métodos , Frequência Cardíaca , Monitorização Ambulatorial/instrumentação , Processamento de Sinais Assistido por Computador , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Algoritmos , Calibragem , Bases de Dados Factuais , Entropia , Feminino , Humanos , Masculino , Modelos Estatísticos , Probabilidade , Adulto Jovem
10.
Comput Math Methods Med ; 2015: 695054, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26075015

RESUMO

This paper aims to develop a general framework for accurately tracking and quantitatively characterizing multiple cells (objects) when collision and division between cells arise. Through introducing three types of interaction events among cells, namely, independence, collision, and division, the corresponding dynamic models are defined and an augmented interacting multiple model particle filter tracking algorithm is first proposed for spatially adjacent cells with varying size. In addition, to reduce the ambiguity of correspondence between frames, both the estimated cell dynamic parameters and cell size are further utilized to identify cells of interest. The experiments have been conducted on two real cell image sequences characterized with cells collision, division, or number variation, and the resulting dynamic parameters such as instant velocity, turn rate were obtained and analyzed.


Assuntos
Algoritmos , Fenômenos Fisiológicos Celulares , Rastreamento de Células/métodos , Interpretação de Imagem Assistida por Computador/métodos , Movimento Celular , Rastreamento de Células/estatística & dados numéricos , Biologia Computacional , Humanos , Modelos Biológicos , Reconhecimento Automatizado de Padrão/métodos , Reconhecimento Automatizado de Padrão/estatística & dados numéricos
11.
Chin Med J (Engl) ; 125(14): 2538-42, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22882936

RESUMO

BACKGROUND: Technetium-99m or (99m)Tc is widely used for labeling peptide in nuclear medicine. Somatostatin and its analog can inhibit tumor cell growth after binding with its receptor. This research was to study the preclinical effect of a new (99m)Tc-6-hydrazinopyridine-3-carboxylic acid (HYNIC)-depreotide, indirect (99m)Tc labeling of depreotide using HYNIC as a bifunctional chelator. METHODS: The cyclopeptide, cyclo-[(N-Me) Phe-Tyr-D-Trp-Lys-Val-Hcy], the linear peptide, and [ClCH(2)-CO×b-Dap-Lys- Cys-Lys×amide] were synthesized by Fmoc solid-phase synthesis. The cyclopeptide and the linear peptide were linked by liquid-phase synthesis. The product depreotide was isolated and purified by high performance liquid chromatography and was confirmed by mass spectrography. Depreotide was labeled with (99m)Tc through a direct labeling method, using HYNIC as a bifunctional chelator. Paper chromatography method was used to calculate the labeling rate, and through the comparative analysis selected the best mark conditions. The new (99m)Tc-HYNIC-depreotide was tested by high-performance liquid chromatography (HPLC). The internalization and externalization rates of the new (99m)Tc-HYNIC-depreotide were studied in A549 cells. Furthermore, biodistribution of the radiopeptide was studied in nude mice, bearing tumors from human lung carcinoma cells SPC-A1. RESULTS: The molecular of synthesize depreotide was 1358, and the purity of it was 95.29%. The labeling efficiency of (99m)Tc-HYNIC-depreotide was highest at pH 6.0 and 15°C, about (70.95 ± 0.84)%. The labeling rate of the new (99m)Tc-HYNIC-depreotide rose to a peak of (20.75 ± 0.48)% at 60 minutes in A549 cells at 37°C and decreased slightly later, while it elevated gradually during the time course at 4°C and 25°C. The internalization rate of the new (99m)Tc-HYNIC-depreotide at 37°C increased gradually and reached the peak of 84.4% in 120 minutes, while the externalization rate of the new (99m)Tc-HYNIC-depreotide was always less than 20%. In mice bearing the experimental SPC-A1 tumor, the new (99m)Tc-HYNIC-depreotide demonstrated a high tumor uptake of (4.05 ± 0.04)% ID/g at 1.5 hpi and remained high ((2.51 ± 0.06)% ID/g) at 4 hpi. The tumor-to-lung activity concentration ratio (T/Lu) was very high for the new (99m)Tc-HYNIC-depreotide at all time points. So did the tumor-to-muscle activity (T/Mu) and tumor-to-blood activity concentration ratios (T/Bl). CONCLUSION: The findings suggested that the new (99m)Tc-HYNIC-depreotide might be a promising candidate radiopharmaceutical for imaging somatostatin receptor positive lung cancer.


Assuntos
Hidrazinas/química , Neoplasias Pulmonares/patologia , Ácidos Nicotínicos/química , Tecnécio/química , Animais , Linhagem Celular Tumoral , Humanos , Neoplasias Pulmonares/metabolismo , Masculino , Camundongos , Camundongos Nus , Receptores de Somatostatina/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA