CT-based radiomic analysis for categorization of ovarian sex cord-stromal tumors and epithelial ovarian cancers.

PURPOSE: To evaluate the diagnostic potential of radiomic analyses based on machine learning that rely on contrast-enhanced computerized tomography (CT) for categorizing ovarian sex cord-stromal tumors (SCSTs) and epithelial ovarian cancers (EOCs). METHODS: We included a total of 225 patients with 230 tumors, who were randomly divided into training and test cohorts with a ratio of 8:2. Radiomic features were extracted from each tumor and dimensionally reduced using LASSO. We used univariate and multivariate analyses to identify independent predictors from clinical features and conventional CT parameters. Clinic-radiological model, radiomics model and mixed model were constructed respectively. We evaluated model performance via analysis of the receiver operating characteristic (ROC) curve and area under ROC curves (AUCs), and compared it across models using the Delong test. RESULTS: We selected a support vector machine as the best classifier. Both radiomic and mixed model achieved good classification accuracy with AUC values of 0.923/0.930 in the training cohort, and 0.879/0.909 in the test cohort. The mixed model performed significantly better than the model based on clinical radiological information, with AUC values of 0.930 versus 0.826 (p = 0.000) in the training cohort and 0.905 versus 0.788 (p = 0.042) in the test cohort. CONCLUSION: Radiomic analysis based on CT images is a reliable and noninvasive tool for identifying SCSTs and EOCs, outperforming experience radiologists.

Modulation of smoker brain activity and functional connectivity by tDCS: A go/no-go task-state fMRI study.

Background: Transcranial direct current stimulation (tDCS) applied to particular brain areas may reduce a smoker's smoking cravings. Most studies on tDCS mechanisms are performed on brains in the resting state. Therefore, brain activity changes induced by tDCS during tasks need to be further studied. Methods: Forty-six male smokers were randomised to receive anodal tDCS of the left/right dorsolateral prefrontal cortex (DLPFC) or sham tDCS. A go/no-go task was performed before and after stimulation, respectively. Brain activity and functional connectivity (FC) changes during the task state before and after tDCS were used for comparison. Results: This study revealed that the anodal stimulation over one DLPFC area caused decreased activity in the ipsilateral precuneus during the go task state. Right DLPFC stimulation increased the FC between the bilateral DLPFCs and the right anterior cingulate cortex (ACC), which is closely associated with cognition and inhibition of executive functions. Additionally, the study showed variations in brain activity depending on whether the anode was positioned over the right or left DLPFC (R-DLPFC or L-DLPFC). Conclusion: During the go task, tDCS might exert a suppressive effect on some brain areas, such as the precuneus. Stimulation on the R-DLPFC might strengthen the FC between the right ACC and the bilateral DLPFCs, which could enhance the ability of behavioural decision-making and inhibition to solve conflicts effectively. Stimulating the L-DLPFC alone could increase the FC of bilateral DLPFCs with some brain regions associated with response inhibition.

Evaluation and prediction method of railway passenger long-term vibration comfort under complex operating conditions.

Vibration contributes large increases in railway passenger discomfort during long-term sitting. Discomfort caused by vibration may differ in different operation conditions. This paper conducted field measurements to investigate the interrelationships between the three. Participants completed a 240-min train journey with their whole-body vibration, subjective comfort ratings and train operating parameters being recorded. A large correlation was observed between the estimated vibration dose value and subjective comfort. The relationship that vibration magnitude significantly increases with increasing the train speed and tunnel density was also found and quantified. A vibration exposure limit of 2.08 m/s1.75 corresponding to the boundary between subjective ratings of comfortable and discomfortable was obtained. Based on the exposure limit and the quantified relationship, a vibration comfort prediction method that can calculate the passenger's maximum tolerance time under a given operation condition was proposed and may help in determining the optimal operating speed and tunnels distribution to alleviate vibration discomfort. Practitioner summary: Similar to the guide to effect of vibration on health in current standard, a vibration exposure limit regarding comfort was provided for reference when assessing long-term vibration comfort. Meanwhile, a prediction method was proposed for determining the best train operating speed and tunnels distribution, thereby alleviating railway passengers' vibration discomfort.

Assessment of passenger long-term vibration discomfort: a field study in high-speed train environments.

This study revealed the mechanism of long-term passenger vibration discomfort in high-speed trains and proposed a novel evaluation model to assess it, while the most popular international standard ISO 2631-1 is unsuitable. Here, a field test was conducted to investigate the long-term passenger vibration comfort in high-speed trains under different operation environments by the measurement of the whole-body vibration (WBV) and the subjective ratings of passenger comfort. During the whole sitting period of high-speed train passengers, the phenomena 'compensatory degradation' and 'discomfort accumulation' were found, which meant that the brief termination of vibration cannot fundamentally alleviate passenger vibration comfort. And the vibration comfort can be evaluated by the product of exposure time and the novel vibration acceleration index we proposed. Meanwhile, high-speed trains with higher velocities or running in tunnel environments have higher frequency-weighted WBV amplitude than open-air and lower velocities, which caused more vibration discomfort of passengers. Practitioner Summary: This field study provided data support for ensuring the occupational health of train drivers whose work routes involve a large number of tunnels and improving passenger vibration comfort. Meanwhile, a novel idea was provided for evaluating the vibration comfort of passengers who prolonged exposure to low-amplitude environments.

Investigation of A Slow-Light Enhanced Near-Infrared Absorption Spectroscopic Gas Sensor, Based on Hollow-Core Photonic Band-Gap Fiber.

Generic modeling and analysis of a slow-light enhanced absorption spectroscopic gas sensor was proposed, using a mode-tuned, hollow-core, photonic band-gap fiber (HC-PBF) as an absorption gas cell. Mode characteristics of the un-infiltrated and infiltrated HC-PBF and gas absorption enhancement of the infiltrated HC-PBF were analyzed. A general rule of microfluidic parameters for targeting different gas species in the near-infrared was obtained. Ammonia (NH3) was used as an example to explore the effects of slow light on gas detection. The second harmonic (2f) signal and Allan deviation were theoretically investigated based on the derived formulations.