High-frequency steady-state asymmetric visual evoked potential (SSaVEP) provides a new paradigm for designing comfortable and practical brain-computer interface (BCI) systems. However, due to the weak amplitude and strong noise of high-frequency signals, it is of great significance to study how to enhance their signal features. In this study, a 30 Hz high-frequency visual stimulus was used, and the peripheral visual field was equally divided into eight annular sectors. Eight kinds of annular sector pairs were selected based on the mapping relationship of visual space onto the primary visual cortex (V1), and three phases (in-phase[0o, 0o], anti-phase [0o, 180o], and anti-phase [180o, 0o]) were designed for each annular sector pair to explore response intensity and signal-to-noise ratio under phase modulation. A total of 8 healthy subjects were recruited in the experiment. The results showed that three annular sector pairs exhibited significant differences in SSaVEP features under phase modulation at 30 Hz high-frequency stimulation. And the spatial feature analysis showed that the two types of features of the annular sector pair in the lower visual field were significantly higher than those in the upper visual field. This study further used the filter bank and ensemble task-related component analysis to calculate the classification accuracy of annular sector pairs under three-phase modulations, and the average accuracy was up to 91.5%, which proved that the phase-modulated SSaVEP features could be used to encode high- frequency SSaVEP. In summary, the results of this study provide new ideas for enhancing the features of high-frequency SSaVEP signals and expanding the instruction set of the traditional steady state visual evoked potential paradigm.
Objective To explore the correlation between the quantitative and qualitative features of CT images and the invasiveness of pulmonary ground-glass nodules, providing reference value for preoperative planning of patients with ground-glass nodules. MethodsThe patients with ground-glass nodules who underwent surgical treatment and were diagnosed with pulmonary adenocarcinoma from September 2020 to July 2022 at the Third Affiliated Hospital of Kunming Medical University were collected. Based on the pathological diagnosis results, they were divided into two groups: a non-invasive adenocarcinoma group with in situ and minimally invasive adenocarcinoma, and an invasive adenocarcinoma group. Imaging features were collected, and a univariate logistic regression analysis was conducted on the clinical and imaging data of the patients. Variables with statistical difference were selected for multivariate logistic regression analysis to establish a predictive model of invasive adenocarcinoma based on independent risk factors. Finally, the sensitivity and specificity were calculated based on the Youden index. Results A total of 555 patients were collected. The were 310 patients in the non-invasive adenocarcinoma group, including 235 females and 75 males, with a meadian age of 49 (43, 58) years, and 245 patients in the invasive adenocarcinoma group, including 163 females and 82 males, with a meadian age of 53 (46, 61) years. The binary logistic regression analysis showed that the maximum diameter (OR=4.707, 95%CI 2.060 to 10.758), consolidation/tumor ratio (CTR, OR=1.027, 95%CI 1.011 to 1.043), maximum CT value (OR=1.025, 95%CI 1.004 to 1.047), mean CT value (OR=1.035, 95%CI 1.008 to 1.063), spiculation sign (OR=2.055, 95%CI 1.148 to 3.679), and vascular convergence sign (OR=2.508, 95%CI 1.345 to 4.676) were independent risk factors for the occurrence of invasive adenocarcinoma (P<0.05). Based on the independent predictive factors, a predictive model of invasive adenocarcinoma was constructed. The formula for the model prediction was: Logit(P)=–1.293+1.549×maximum diameter of lesion+0.026×CTR+0.025×maximum CT value+0.034×mean CT value+0.72×spiculation sign+0.919×vascular convergence sign. The area under the receiver operating characteristic curve of the model was 0.910 (95%CI 0.885 to 0.934), indicating that the model had good discrimination ability. The calibration curve showed that the predictive model had good calibration, and the decision analysis curve showed that the model had good clinical utility. Conclusion The predictive model combining quantitative and qualitative features of CT has a good predictive ability for the invasiveness of ground-glass nodules. Its predictive performance is higher than any single indicator.
【Abstract】 Objective To isolate and culture human amniotic fluid-derived mesenchymal stem cells (HAFMSCs),to investigate a better cryopreservation protocol of HAFMSCs and to observe the biocharacteristics and the multi-potential of HAFMSCs after cryopreservation for the further fundamental researches and cl inical appl ications. Methods HAFMSCswere isolated from the amniotic fluid of pregnant women during the second trimester by the improved two-step method.HAFMSCs were cryopreserved with different cryopreservation protocols (containing different contents of FBS and DMSO atcryoprotectant) in l iquid nitrogen for 12 weeks. The biocharacteristics of the HAFMSCs after cryopreservation were analyzed. The growth characteristics were observed by MTT method and the growth curves were drawn. The surface antigens of HAFMSCs were detected using flow cytometry, including CD29, CD34, CD44, CD45, CD73, and CD90. The adi pogenic and osteogenic differentiation abil ities of HAFMSCs were observed. The mRNA levels of Oct-4 and Nanog of the HAFMSCs were compared between before and after cryopreservations. Results At 12 weeks after cryopreservation, different protocols had different effects on the cell viabil ity; the better formula of cryoprotectant was 50% DMEM, 40% FBS, and 10% DMSO. After cryopreservation, the cells proliferated rapidly and the growth curves showed “S” shape, which was the same as the cells before cryopreservation. Phenotype showed that HAFMSCs were positive for the surface markers CD29, CD44, CD73, and CD90, and negative for CD34 and CD45. After 21 days of adi pogenic differentiation, the l ipid droplets were observed by oil red O staining. After 21 days of osteogenic differentiation, the calcium mineralizations were verified by von Kossa staining. There was no significant difference (P gt; 0.05) in the mRNA levels of Oct-4 and Nanog between before and after cryopreservations. Conclusion HAFMSCs have rapid proliferation and multi-potential in vitro. The cells have high viabil ities and no changes of the biocharacteristics and differentiation potential ities after cryopreservation for 12 weeks. Cryoprotectant containing 50% DMEM, 40% FBS, and 10% DMSO is a better cryopreservation protocol.
ObjectiveTo investigate the clinical features and influencing factors for new-onset atrial fibrillation (AF) early after coronary artery bypass grafting.MethodsThe clinical data of 339 patients undergoing coronary artery bypass grafting in our hospital from January 2012 to January 2019 were retrospectively analyzed. There were 267 males and 72 females with an average age of 37-83 (58.03±8.90) years. The clinical features and influencing factors for new-onset AF after surgery were investigated.ResultsThere were 234 patients of off-pump coronary artery bypass grafting (OPCABG), with 36 (15.4%) new-onset AF patients after operation, among whom 16.1% were males and 12.5% were females. There were 105 patients of on-pump coronary artery bypass grafting (CABG), with 39 (37.1%) new-onset AF patients, among whom 40.7% were males and 25.0% were females. The incidence was higher after the CABG surgery than that after the OPCABG surgery (37.1% vs. 15.4%, P<0.05). There was no statistical difference in the incidence rate between males and females (P>0.05). The incidence of new-onset AF after surgery was higher in ≥60 years patients for both operations (18.9% and 45.8%), which was significantly higher than that in <45 years patients (P<0.05). For both operations, the incidence of new-onset AF after surgery was high on the second day (24-48 h) after surgery, and most of the AF lasted for 1 day (P<0.05). The hypertension (OR=4.983, P=0.036), frequent premature atrial contraction or atrial tachycardia (OR=17.682, P=0.002), postoperative creatine kinase isoenzyme MB (CKMB) (OR=0.152, P=0.042), left anterior and posterior diameters (OR=17.614, P<0.001) and preoperative ejection fraction (OR=7.094, P=0.011) were influencing factors for new-onset AF after OPCABG. Diabetes (OR=11.631, P=0.020), other cardiac malformations (OR=29.023, P=0.002), frequent premature ventricular contraction or ventricular tachycardia (OR=0.047, P=0.001), and postoperative CKMB (OR=3.672, P=0.040) were influencing factors for new-onset AF after CABG.ConclusionThe incidence of new-onset AF after CABG is higher than that after OPCABG, and it increases with age increasing. There is no difference in the incidence between males and females. The influencing factors for the two operations are different.
Autoimmune pancreatitis (AIP) is a unique subtype of chronic pancreatitis, which shares many clinical presentations with pancreatic ductal adenocarcinoma (PDA). The misdiagnosis of AIP often leads to unnecessary pancreatic resection. 18F-FDG positron emission tomography/ computed tomography (PET/CT) could provide comprehensive information on the morphology, density, and functional metabolism of the pancreas at the same time. It has been proved to be a promising modality for noninvasive differentiation between AIP and PDA. However, there is a lack of clinical analysis of PET/CT image texture features. Difficulty still remains in differentiating AIP and PDA based on commonly used diagnostic methods. Therefore, this paper studied the differentiation of AIP and PDA based on multi-modality texture features. We utilized multiple feature extraction algorithms to extract the texture features from CT and PET images at first. Then, the Fisher criterion and sequence forward floating selection algorithm (SFFS) combined with support vector machine (SVM) was employed to select the optimal multi-modality feature subset. Finally, the SVM classifier was used to differentiate AIP from PDA. The results prove that texture analysis of lesions helps to achieve accurate differentiation of AIP and PDA.
Electroencephalogram (EEG) is the primary tool in investigation of the brain science. It is necessary to carry out a deepgoing study into the characteristics and information hidden in EEGs to meet the needs of the clinical research. In this paper, we present a wavelet-nonlinear dynamic methodology for analysis of nonlinear characteristic of EEGs and delta, theta, alpha, and beta sub-bands. We therefore studied the effectiveness of correlation dimension (CD), largest Lyapunov exponen, and approximate entropy (ApEn) in differentiation between the interictal EEG and ictal EEG based on statistical significance of the differences. The results showed that the nonlinear dynamic characteristic of EEG and EEG subbands could be used as effective identification statistics in detecting seizures.
Objective To explore the histochemical staining for distinguishing and local izing nerve fibers and fascicles at histological level in three-dimensional reconstruction of peri pheral nerves. Methods The right median nerve was harvested from one fresh cadaver and embedded in OCT compound. The sample was serially horizontally sl iced with 6 μm thickness. All sections were stained with Karnovsky-Roots method (group A, n=30) firstly and then stained with toluidine blue (group B, =28) and Ponceau 2R (group C, n=21) in proper sequence. The results of each step were taken photos (× 100). After successfully stitching, the two-dimensional panorama images were compared, including texture feature, the number and aver gray level of area showing acetylchol inesterase (AchE) activity, and result of auto microscopic medical image segmentation. Results In groups A, B, and C, the number of AchE-positive area was (21.63 ± 4.06)× 102, (20.64 ± 3.51)× 102, and (20.54 ± 5.71)× 102, respectively, showing no significant difference among 3 groups (F=0.64, P=0.54); the mean gray level was (1.41 ± 0.06)× 102, (1.10 ± 0.05)× 102, and (1.14 ± 0.07)× 102, respectively, showing significant differences between group A and groups B and C (P lt; 0.001). In the image of group A, only AchE-positive area was stained; in the image of group B, myelin sheath was obscure; and in the image of group C, axons and myelin sheath could be indentified, the character of nerve fibers could be distinguished clearly and accurately, and the image segmentation of fascicles could be achieved easier than other 2 images. Conclusion The image of Karnovsky-Roots-toluidine blue-Ponceau 2R staining has no effect on the AchE-positive area in the image of Karnovsky-Roots staining and shows better texture feature. This improved histochemical process may provide ideal image for the three-dimensional reconstruction of peri pheral nerves.
Objective To analyze the impact of body mass index (BMI) on tumor characteristics of colorectal patients served by West China Hospital as a regional center in the current version of Database from Colorectal Cancer (DACCA). MethodsThe data of DACCA was updated on October 16, 2021. All data items included BMI, precancerous lesions, cancer family, tumor site, tumor morphology, location, differentiation, pathological properties of tumor, obstruction, overlap, perforation, pain, edema, and bleeding. The patients were divided into lean (BMI<18.5 kg/m2), normal (BMI 18.5–23.9 kg/m2), overweight (BMI 24.0–27.9 kg/m2) and obesity (BMI≥28.0 kg/m2) by Chinese classification methods. ResultsAfter scanning, 5 761 data rows were analyzed. Chi-square test showed that there was significant difference in the type composition ratio of tumor location in colorectal cancer patients under different BMI groups (χ2=31.477, P<0.001). Rank sum test showed that there was significant difference in the degree of obstruction (H=42.490, P<0.001), intussusception (H=8.179, P=0.042), edema (H=14.795, P=0.002), and bleeding (H=9.884, P=0.020) among different BMI groups. ConclusionsThe BMI classification of colorectal cancer patients is related to the location of tumor and the occurrence of some tumor complications. Patients with tumor involving intestinal lumens for one week are more likely to have low BMI. The patients with low BMI are more likely to have severe bleeding, obstruction, intestinal intussusception, and severe intestinal wall edema.
ObjectiveTo analyze the clinical and epidemiological characteristics of hospitalized avian influenza A (H7N9) virus infections in Hunan province from 2013 to 2017, and provide evidences for control, diagnosis and treatment of this disease.MethodsNinety-one hospitalized patients were confirmed with H7N9 infection in Hunan. Excluding 2 patients less than 18 years old and 10 with missing data, 79 patients with H7N9 infection were analyzed.ResultsMost confirmed cases were affected in the second and fifth epidemic wave and number of patients in the fifth wave was more than the sum in prior 4 waves. Epidemiological characteristics, clinical symptoms and case fatality did not change significantly. Administration of antiviral drugs was more active in the fifth wave [from illness onset to antiviral drug: (6.3±2.4)d vs. (7.6±2.4)d, P=0.047]. Multiple logistic regression analysis showed that shock (OR=4.683, 95%CI 1.136–19.301, P=0.033) was the independent risk factor of H7N9 infections. There were no significant differences in case fatality among group oseltamivir, group oseltamivir+peramivir, and group peramivir.ConclusionsPatients with avian influenza A (H7N9) increased in the fifth wave but clinical characteristics changed little. Antiviral treatment should be more active. Shock is an independent risk factor of H7N9 infections. Oseltamivir-peramivir biotherapy can not reduce case fatality compared with oseltamivir or peramivir monotherapy.