The Eurasian seismic belt is the second largest seismic zone in the world. It has numerous seismic activities which have enormous impact on human’s life. It is of importance to study the ...spatio–temporal characteristics of the Eurasian seismic belt. As we can learn from previous studies, fractal and fractal dimension theories can be used to study seismic activities. In general, the temporal sequence and the spatio sequence of earthquakes both exhibit the fractal structures. When huge earthquakes occur, the fractal dimension of the temporal sequence is very low. As the days went by, the value of fractal dimension fluctuates. The seismic data from 1973 to 2014 in The Eurasian seismic belt are selected as the object of this study. Based on the single fractal model, the complex structure of the seismic spatio and temporal distribution in the seismic belt is quantitatively evaluated. Results show that over time the time interval of the seismic activity shortened, and the seismic activity on the Eurasian seismic belt has a nonlinear structure and self-similar characteristics. From the perspective of space, the fractal dimension of the Eurasian seismic belt tends to grow with time, and it also has a nonlinear structure and self-similar characteristics. When the temporal unit is set as 1 year, the accumulation and release of energy are probably periodic: the minor period might be about 8.5 years, and the major period might be about 13 years.
In recent years, many studies have shown that the gut microbiota can affect the occurrence and development of a variety of human diseases. A variety of skin diseases are related to the regulation of ...the gut–skin axis, such as psoriasis, atopic dermatitis, and acne. Gut microbial dysbiosis can promote the development of these diseases. The gut microbiota can affect estrogen metabolism, β-glucuronidase secreted by the gut microbiota can promote the reabsorption of estrogen by the gut, and estrogen is transported to other parts of the body through the circulatory system. The occurrence and development of melasma are closely related to abnormal metabolism of estrogen. The relationship between the structure of the gut microbiota and melasma remains unclear. Epidemiological surveys were conducted in patients with melasma and healthy subjects (control group) in this study. The feces were collected for 16S rRNA sequencing analysis of the gut microbiota. To compare the similarities and differences in species diversity of the gut microbiota between these two groups, we calculated the α-diversity and β-diversity indices and analyzed the differences between them. We found that the abundance of
Collinsella
spp.,
Actinomyces
spp. (belonging to Actinobacteria),
Parabacteroides
spp.,
Bacteroides
spp.,
Paraprevotella
spp. (belonging to Bacteroidetes),
Blautia
spp., and
Roseburia
spp. (belonging to Firmicutes) in the melasma group were significantly different compared with that in the healthy group. The largest difference was found in Actinobacteria (
p
< 0.05), and there were also significant differences in the abundance of Coriobacteriia, Actinobacteria, Coriobacteriales, Coriobacteriaceae, and
Collinsella
spp. between the two groups (all
p
< 0.05). Many of these differences in the microbiota were closely related to the production of β-glucuronidase and the regulation of estrogen synthesis or metabolism. Changes in the gut microbiota structure and the biological effects of
Collinsella
spp. in the microbiota in patients with melasma can play an important role in the occurrence and development of melasma by affecting the body’s estrogen metabolism. This study provides a theoretical basis and experimental data reference for future studies on the relationship between the gut microbiota and melasma, and may be helpful for the prevention and treatment of melasma.
Abstract
Background
Numerous studies have reported the association between tea intake and lung diseases. However, the probable relationship between tea consumption on lung diseases still remain ...controversial and it is unclear whether these findings are due to reverse causality or confounding factor.
Methods
In order to systematically investigate the causal connection between tea intake on respiratory system disorders, we employed a two-sample Mendelian randomized (MR) study. Genetic instruments for tea intake were identified from a genome-wide association study (GWAS) involving 447,385 individuals. Data on lung diseases were collected from a variety of publicly available genome-wide association studies. The main method used for MR analysis is the inverse variance weighting (IVW) method. To ensure the accuracy of the findings, further sensitivity analysis was conducted.
Results
The IVW method in our MR analysis revealed no evidence to support a causal relationship between tea intake and lung diseases (IPF: OR = 0.997, 95% CI = 0.994-1.000,
p
= 0.065; Lung cancer: OR = 1.003, 95% CI = 0.998–1.008,
P
= 0.261; COPD: OR = 1.001, 95% CI = 0.993–1.006,
p
= 0.552; acute bronchitis: OR = 0.919, 95% CI = 0.536–1.576,
p
= 0.759; tuberculosis: OR = 1.002, 95% CI = 0.998–1.008,
p
= 0.301; pneumonia: OR = 0.789, 95% CI = 0.583–1.068,
p
= 0.125). The reliability of the results was further demonstrated by four additional MR analysis techniques and additional sensitivity testing.
Conclusion
We found no evidence of a link between tea intake on lung diseases in our MR results based on genetic information.
Image quality variation is a prominent cause of performance degradation for intelligent disease diagnostic models in clinical applications. Image quality issues are particularly prominent in ...infantile fundus photography due to poor patient cooperation, which poses a high risk of misdiagnosis. Here, we developed a deep learning-based image quality assessment and enhancement system (DeepQuality) for infantile fundus images to improve infant retinopathy screening. DeepQuality can accurately detect various quality defects concerning integrity, illumination, and clarity with area under the curve (AUC) values ranging from 0.933 to 0.995. It can also comprehensively score the overall quality of each fundus photograph. By analyzing 2,015,758 infantile fundus photographs from real-world settings using DeepQuality, we found that 58.3% of them had varying degrees of quality defects, and large variations were observed among different regions and categories of hospitals. Additionally, DeepQuality provides quality enhancement based on the results of quality assessment. After quality enhancement, the performance of retinopathy of prematurity (ROP) diagnosis of clinicians was significantly improved. Moreover, the integration of DeepQuality and AI diagnostic models can effectively improve the model performance for detecting ROP. This study may be an important reference for the future development of other image-based intelligent disease screening systems.
An improved method for soft tissue modeling Tang, Yushan; Liu, Shan; Deng, Yaru ...
Biomedical signal processing and control,
March 2021, 2021-03-00, Letnik:
65
Journal Article
Recenzirano
•The Particle-Spring soft tissue modeling method is improved in this paper.•Estimating the parameters of the Particle-Spring model by finite element method.•Two experiments are designed to compare ...the accuracy of the improved model and the traditional empirical particle model.•Summarizing the merits and demerits of the model, and putting forward the direction of future research.
The technique of force and haptic reappearance is an effective method to solve the shortage of haptic presence and improve the medical robots' practicability. Soft tissue models, the core of force-haptic reappearance systems, play a decisive role in its performance. The establishment of realistic soft tissue models can improve the system's authenticity and efficiency and better realize the representation of force and touch in the interaction process.
At present, there exists a contradiction between timeliness and accuracy in soft tissue modeling. This paper combined the finite element method with the mass-spring model. We estimated the mass-spring model's parameters with the finite element method by neglecting the damping coefficient and obtained the relationship between the elastic coefficients. Then, according to the real measurement data of soft tissue in literature and the stress-strain curve obtained from real measurement, the values of a, A, ε, ksσ were determined. Through those methods above, an improved soft tissue model was obtained. Through our comparison experiments, the improved spring particle model has a high degree of data fitting, and the force value under the same displacement is smaller. Moreover, the improved model's force-displacement curve in the large deformation stage is still very close to the measurement curve of the volume, which cannot be achieved by the empirical spring particle model. These comparative experiments show that the improved finite element-based particle spring model can better consider the timeliness and accuracy and simulate the soft tissue more accurately.
•In this paper, the force-displacement, stress relaxation and creep data of the soft tissue model were compared with those of the real soft tissue.•The data of the model are within the range of ...measured values, and the model has a accuracy and validity which is superior to the empirical particle-spring model.•The frame rate in this paper is much higher than the frame rate required for real-time performance, which verifies the real-time performance of the system.
Force haptic reappearance technology is considered to be one of the top ten technologies that can change human life in the future. It has broad application prospects and market demand. Most of the existing medical robots, especially the remote diagnosis and treatment robots, lack haptic feedback, or the calculation of feedback force is insufficient. Haptic reappearance technology is an effective method to solve the problem of haptic presence and improve the practicability of medical robot.
The ultimate goal of the force haptic reappearance system is to let the operator feel the haptic feedback when interacting with the soft tissue model in the virtual environment in real time. Haptic device is the necessary condition to realize force haptic reappearance, and it is an essential part of the system. Its important role is to introduce the external force imposed by the operator into the virtual environment, and let the operator feel the force in the virtual environment, which effectively guarantees the operator's sense of reality and immersion when interacting with the virtual environment.
Therefore, starting with the key technology of force and haptic reappearance system, this paper studies the construction of force and haptic reappearance system. Soft tissue surface model is drawn by OpenGL, and hand model is drawn by 3Ds Max. The haptic reappearance and visual feedback of soft tissue model of hand palpation are realized. The quality of feedback is evaluated. The haptic reappearance is stable and realistic, and the visual feedback is smooth. This indicates that the system has a certain application value and is worth to promote to the public.
A novel electrochemical biosensor was developed for the detection of epinephrine (EP) by immobilizing double-strand DNA (dsDNA) bound with copper ions on a gold electrode (Cu2+/dsDNA/MCH/AuE). The ...electrochemical behavior of EP at Cu2+/dsDNA/MCH/AuE was examined, and the results demonstrated a significant enhancement in the electrocatalytic oxidation peak current of EP due to the formation of a stable G-Cu(II)-G sandwich structure between Cu2+ and guanine at the modified electrode. The modification process of the electrode was characterized by scanning electron microscopy, infrared spectroscopy, electrochemical impedance spectroscopy, and differential pulse voltammetry. A study on the effect of pH in phosphate buffer solution on the electrochemical oxidation of EP indicated that the catalytic oxidation process was pH-dependent. A plot of catalytic current versus EP concentration exhibited a dual-linear relationship within two ranges: 1.0–12.5 μM and 12.5–1000.0 μM, with correlation coefficients of 0.995 and 0.997, respectively. The limit of detection was determined to be 47 nM (S/N = 3). According to the calculated Hill coefficient (0.99), it can be concluded that the electrocatalytic process followed the Michaelis-Menten kinetic mechanism. The maximum catalytic current Im was 25 μA, while the apparent Michaelis-Menten constant Km was 1.425 mM. These findings indicated excellent electrocatalytic activity of the modified electrode towards oxidation of EP. The developed biosensor successfully detected EP in spiked mouse serum as well as epinephrine hydrochloride injection with high selectivity, sensitivity, stability, and accuracy.
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•A Guanine-Cu (II)-Guanine sandwich structure specially binds with epinephrine.•The electrocatalytic process obeys the Michaelis-Menten kinetic mechanism.•The biosensor with high selectivity, sensitivity, stability and wide linear range.
In the fundamental harmonic approximation (FHA) modeling of dual bridge series resonant dc-dc converters (DBSRCs), the approximation error of the FHA model will lead to low accuracy of optimization ...schemes, which will reduce the efficiency of DBSRCs. In this article, first, the time domain analysis (TDA) modeling of the DBSRC is adopted, which can describe the characteristics of the DBSRC accurately. Second, the extended phase shift modulation based on the TDA modeling is discussed, and the backflow power model with the TDA of the DBSRC is developed. On this basis, a zero-backflow power optimization scheme is proposed. In addition, the effects of dead time are analyzed and the compensation method is proposed. The proposed backflow power optimization method with dead time compensation can achieve zero-backflow power and improve the efficiency of the DBSRC. Especially, the proposed method with TDA modeling is more excellent when DBSRC operates in wide voltage range conditions. Finally, a comprehensive experiment comparison of DBSRC under the minimum current trajectory with FHA modeling and the proposed method with TDA modeling is discussed. The experimental results have verified the effectiveness of the proposed scheme.
Cadmium (Cd) has long been recognized as toxic pollutant to crops worldwide. The biosynthesis of glutathione-dependent phytochelatin (PC) plays crucial roles in the detoxification of Cd in plants. ...However, its regulatory mechanism remains elusive. Here, we revealed that Arabidopsis transcription factor WRKY45 confers Cd tolerance via promoting the expression of PC synthesis-related genes PCS1 and PCS2, respectively. Firstly, we found that Cd stress induces the transcript levels of WRKY45 and its protein abundance. Accordingly, in contrast to wild type Col-0, the increased sensitivity to Cd is observed in wrky45 mutant, while overexpressing WRKY45 plants are more tolerant to Cd. Secondly, quantitative real-time PCR revealed that the expression of AtPCS1 and AtPCS2 is stimulated in overexpressing WRKY45 plants, but decreased in wrky45 mutant. Thirdly, WRKY45 promotes the expression of PCS1 and PCS2, electrophoresis mobility shift assay analysis uncovered that WRKY45 directly binds to the W-box cis-element of PCS2 promoter. Lastly, the overexpression of WRKY45 in Col-0 leads to more accumulation of PCs in Arabidopsis, and the overexpression of PCS1 or PCS2 in wrky45 mutant plants rescues the phenotypes induced by Cd stress. In conclusion, our results show that AtWRKY45 positively regulates Cd tolerance in Arabidopsis via activating PCS1 and PCS2 expression.
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●The transcripts of Arabidopsis transcription factor WRKY45 and protein level of WRKY45 are induced by Cd stress.●Overexpressing WRKY45 in Arabidopsis increases the resistance to Cd stress, the wrky45 plants are sensitive to Cd toxicity.●The phytochelatin synthase-1 (PCS1) and PCS2 are the target gene of WRKY45.●Overexpressing PCS1 or PCS2 rescues the resistance of wrky45 mutant to Cd, thus WRKY45 acts upstream of PCS1 or PCS2.
•A novel signal amplification strategy for ferrocenyl indicators based DNA sensors.•The sensitivity of DNA sensor is increased by 3 times in the presence of α-CD.•The principle of the signal ...amplification strategy is disclosed.•Universality for other ferrocenyl indicators with similar structures in this work.
The synthesized ferrocene appended naphthalimide derivative (FND) exhibited great binding ability toward dsDNA, while its usage as the electrochemical hybridization indicator was restricted by the poor water solubility. Herein, a simple and effective signal amplification strategy for FND based label-free DNA biosensors was developed based on the interaction between FND and cyclodextrin. α-Cyclodextrin (α-CD), β-cyclodextrin (β-CD) and γ-cyclodextrin (γ-CD) were helpful to amplify the signal of the DNA biosensor, while the signal amplification effect of α-CD was better than that of β-CD and γ-CD. Under the optimum conditions, there was a 3-fold increase in the sensitivity of the DNA biosensor after the addition of α-CD. The interaction between FND and α-/β-/γ-CD was investigated by differential pulse voltammetry and fluorescence experiment. Experimental results showed that α-CD not only minimized the impact on the electrochemical activity of FND but also improved the dispersity of FND in aqueous solution. That was why the proposed biosensor showed higher sensitivity in the presence of α-CD. This strategy was universal for other ferrocenyl indicators with similar structures as used in this work.
