SARS-CoV-2 caused severe threat to people's health all over the world,and has attracted widespread attention from researchers.The spike protein of SARS-CoV-2 is a key structure mediating the binding of the virus to its host.Therefore,it is im-portant to elucidate the mechanism of spike protein-induced immune responses.We've reviewed the structure of spike protein from al-pha to omicron variant,as well as the potential mechanisms of spike-induced in multiple systems,so as to provide a reference for dis-ease prevention and treatment.

Objective:To investigate the relationship between renin-angiotensin system (RAS) and bone mineral density in children with glucocorticoids-induced osteoporosis (GIOP) .Methods:From Apr. 2020 to May. 2021, 53 children with GIOP were recruited in the Children’s Hospital of Taiyuan Maternal and Child Health Hospital and included in the observation group, and 47 children who received glucocorticoid therapy but did not suffer from GIOP were included in the control group. The levels of serum RAS components and bone mineral density of the two groups of pediatric patients were detected and compared, and the risk clinical indicators affecting bone mineral density and GIOP were analyzed.Results:There were no significant differences between the observation group and the control group in terms of gender, age, BMI, disease type, type of glucocorticoid use, use of anti-osteoporosis (OP) drugs, expression levels of Angiotensin converting enzyme 2 (ACE2) or angiotensin II (Ang Ⅱ) (all P>0.05) . The bone density value of the observation group was lower than those of the control group, and the levels of angiotensin converting enzyme (ACE) (1.19±0.23) , angiotensin receptor 1 (AT1R) (1.24±0.24) , angiotensin receptor 2 (AT2R) (1.14±0.17) , and Mas receptor (MasR) (1.11±0.28) were significantly higher than those of the control group (1.00±0.23, 1.00±0.25, 1.00±0.21, 1.00±0.20) , and the differences were statistically significant (all P<0.05) . Pearson analysis showed that bone mineral density was negatively correlated with the levels of ACE ( r=-0.34, P=0.013) , AT1R ( r=-0.41, P=0.002) and AT2R ( r=-0.34, P=0.014) , and stepwise regression model showed that ACE ( t=-2.21, P=0.032) and AT1R ( t=-2.92, P=0.005) were the main factors affecting bone mineral density. Logistic regression model analysis showed that bone mineral density ( OR=0.85, P<0.001) , Ang Ⅱ ( OR=0.53, P=0.041) and AT2R ( OR=2.00, P=0.024) were independent clinical risk factors affecting GIOP (all P<0.05) . Conclusion:RAS components ACE and AT1R are independent risk factors affecting bone mineral density in children with GIOP, and are significantly correlated with bone mineral density in children.

This study aims to propose a multifrequency time-difference algorithm using spectral constraints. Based on the knowledge of tissue spectrum in the imaging domain, the fraction model was used in conjunction with the finite element method (FEM) to approximate a conductivity distribution. Then a frequency independent parameter (volume or area fraction change) was reconstructed which made it possible to simultaneously employ multifrequency time-difference boundary voltage data and then reduce the degrees of freedom of the reconstruction problem. Furthermore, this will alleviate the illness of the EIT inverse problem and lead to a better reconstruction result. The numerical validation results suggested that the proposed time-difference fraction reconstruction algorithm behaved better than traditional damped least squares algorithm (DLS) especially in the noise suppression capability. Moreover, under the condition of low signal-to-noise ratio, the proposed algorithm had a more obvious advantage in reconstructions of targets shape and position. This algorithm provides an efficient way to simultaneously utilize multifrequency measurement data for time-difference EIT, and leads to a more accurate reconstruction result. It may show us a new direction for the development of time-difference EIT algorithms in the case that the tissue spectrums are known.

When applying deep learning to the automatic segmentation of organs at risk in medical images, we combine two network models of Dense Net and V-Net to develop a Dense V-network for automatic segmentation of three-dimensional computed tomography (CT) images, in order to solve the problems of degradation and gradient disappearance of three-dimensional convolutional neural networks optimization as training samples are insufficient. This algorithm is applied to the delineation of pelvic endangered organs and we take three representative evaluation parameters to quantitatively evaluate the segmentation effect. The clinical result showed that the Dice similarity coefficient values of the bladder, small intestine, rectum, femoral head and spinal cord were all above 0.87 (average was 0.9); Jaccard distance of these were within 2.3 (average was 0.18). Except for the small intestine, the Hausdorff distance of other organs were less than 0.9 cm (average was 0.62 cm). The Dense V-Network has been proven to achieve the accurate segmentation of pelvic endangered organs.
Algorithms ; Humans ; Image Processing, Computer-Assisted ; Imaging, Three-Dimensional ; Neural Networks, Computer ; Organs at Risk ; Pelvis ; Tomography, X-Ray Computed

OBJECTIVETo explore the risk factors contributing to the progression-free survival rate of patients undergoing endoscopic non-curative resection.

METHODSClinicopathological data of patients with early colorectal carcinoma and intraepithelial neoplasia undergoing endoscopic resection in our department from January 2009 to January 2015 were collected. Associated factors affecting the progression-free survival rate of the early colorectal carcinoma after endoscopic non-curative resection were analyzed. Any of the following conditions was defined as endoscopic non-curative resection: (1) positive lateral or vertical cutting margin; (2) submucosa invasion depth ≥1 000 μm; (3) vascular or lymphatic invasion; (4) low differentiation, including signet ring cell carcinoma or mucinous adenocarcinoma; (5) high grade tumor budding.

RESULTSClinicopathological data of 840 cases were collected. According to China's Endoscopic Screening, Diagnosis and Treatment Guidelines for Early Colorectal Cancer, 56(56/840, 6.7%) cases were defined as the non-curative resection, the metastasis or recurrence rate was 14.3%(8/56), 3-year progression-free survival rate was 85.7%(48/56), and 3-year overall survival rate was 94.6%(53/56). Univariate prognostic analysis showed that 3-year progression-free survival rate in low and moderate-high differentiation adenocarcinoma was 25.0% and 90.4%(χ=6.711, P=0.010), in patients with submucosa invasion depth ≥2 000 μm and <2 000 μm was 75.0% and 93.8%(χ=6.745, P=0.009), and in patients with and without vascular or lymphatic invasion was 60.0% and 88.2%(χ=7.708, P=0.005), whose differences were all significant. Multivariate Cox regression analysis revealed that low differentiation adencarcinoma (P=0.015, HR=8.021, 95%CI: 1.499-42.921), invasion depth ≥2 000 μm (HR=6.823, 95%CI: 1.299-35.848) and vascular or lymphatic invasion (HR=18.143, 95%CI: 2.079-158.358) were independent risk factors for the progression-free survival rate of the early colorectal carcinoma after endoscopic non-curative resection.

CONCLUSIONPathology after endoscopic non-curative resection for early colorectal carcinoma indicates that low differentiation adenocarcinoma, submucosa invasion depth ≥2 000 μm and vascular or lymphatic invasion are independent risk factors of poor prognosis.

OBJECTIVETo investigate the security and efficacy of a new endoscopic closure method of large defects after endoscopic full-thickness resection (EFTR) double purse-string suture using two endoloops and metallic clips via single-channel endoscopy.

METHODSClinical data of 23 cases with submucosal tumors (SMT) who received endoscopic resection from June 2015 to July 2016 in our National Cancer Center were collected. For gastric and esophageal SMTs or the mucosa layer injured during submucosal tunneling endoscopic resection (STER), double purse-string suture was conducted after EFTR. The key steps of closure were as follows: the endoloop was installed onto the delivery system and inserted into the gastric cavity to the defect location with endoscopy and then opened; the clips were transported into the gastric cavity from the biopsy channel; the endoloop was fixed onto the full thickness of gastric wall along the edge of the defect by clips one by one between the interval of about 5 mm; the endoloop was tightened slowly till the entire circumference of the defect was sutured, thus, one purse-string suture was done; in accordance with the operation above, another endoloop was released, and the second endoloop was fixed at 5-10 mm to the outer edge of the original one, and tied the endoloop gently; this sequence was continued till there was no gap, thus, the double-purse string suture was finished. A total of 23 patients were enrolled in the study, including 18 with gastric tumor and 5 with esophageal tumor, 15 males and 8 females, with the average age of 56 (19 to 76) years.

RESULTSEighteen cases of gastric SMT were successfully treated by endoscopic EFTR and double purse-string suture. The esophageal mucosa layer of all the 5 cases of esophageal SMT, including tumors of 3 cases located in cervical esophagus at 15-20 cm from the fore-tooth, 1 esophageal leiomyoma case complicated with squamous cell carcinoma in situ, and 1 case of mucosal layer injury during submucosal tunneling endoscopic resection (STER), was successfully repaired by using double purse-string suture. The mean maximum diameter of tumor was 2.3 cm, and the average suture time was 22.8 min. Postoperative pathology showed that 13 cases were gastrointestinal stromal tumors (GIST), 7 cases were leiomyoma, 2 cases were neurilemmoma, and 1 case was leiomyoma complicated with early squamous cell carcinoma in situ. No severe complications occurred during or after the operation.

CONCLUSIONSThe double purse-string suture by using metallic clips and endoloops with single channel endoscope is a relatively safe, easy, and reliable technique for repairing large gastric defect after EFTR. For cervical esophageal SMT, or the SMT combined with superficial mucosal lesions, and for the mucosa layer injury during submucosal tunneling endoscopic resection(STER), double purse-string suture is helpful to perform the closure.

The communication between the students and the teacher was introduced from three aspects of foregone course, communication channel as well as homework and experiment. The individualized teaching mode was described involving expounding common difficulty, assigning and reading over the homework, individualized tutoring after school, on-line responding to the student's question, prompting the student to complete programming and answering questions in evening classes. It's pointed out that the individualized teaching has to take both common knowledge and student difference into considerations. Individulized mode enhances the teaching efficacy greatly.

ObjectiveTo investigate the features of normal and psoriasis skin on ultrasound biomicroscopy (UBM) and explore the method of thickness measurement.MethodsUsing 50 MHz ultrasound probe of biological microscope, ultrasonographic observation and ultrasonic thickness measurement were conducted in 90 normal adults and 40 psoriasis patients. Innormal patients, ultrasound evaluations were performed at 10 different parts of the body skin.ResultsOn sonogram, the normal skin showed a “sandwich” structure with two parallel hyperechoic bands and the middle isoechoic dots and short liens. The sonograms of the psoriasis skin showed obviously thickened epidermis and dermis, disordered internal structure and clear boundary from adjacent normal skin. The range of the epidermis’ thickness measurement was between the medial forearm (0.12±0.03) mm and the palm (0.29±0.15) mm. The range of dermal thickness measurement was between the back hand (1.18±0.32) mm and parasternal (1.55±0.21) mm. Psoriasis skin was thicker than the uninvolved skin (P<0.001). And the dermis’ thickness of uninvolved skin in psoriasis patients was thicker than that of the normal adults (P<0.001).ConclusionNormal adult’s epidermis, dermis and skin appendages can be shown clearly using 50 MHz ultrasound biomicroscopy. And ultrasound biomicroscopy canaccurately measure the thickness of dermis and epidermis, which provides the basis for the diagnosis and treatment of psoriasis.

Objective:　To explore the therapeutic effect and safety of thrombolysis and pure anticoagulation therapy in patients with acute submassive pulmonary embolism. Methods: A total of 63 patients with acute submassive pulmonary embolism were randomly divided into thrombolysis group (n=32) and pure anticoagulation group (n=31). Arterial blood gas index and right heart functional index changes of two groups were observed before treatment and after two-week treatment, and their therapeutic effects were compared and analyzed. Incidence of bleeding and thrombocytopenia were counted in two groups. Results: Compared with before treatment, there were significant improvements in arterial blood gas and right heart functional indexes after treatment in two groups, P<0.05 or <0.01; compared with pure anticoagulation group, there were significant rise in partial pressure of oxygen in artery [PaO2,（77.8±7.3）mmHg vs. (83.4±8.7) mmHg], right ventricular anterior wall motion [RVAWM, (4.9±1.7) mm vs. (5.8±2.2) mm]; and significant descent in alveolar-arterial oxygen difference [P (A-a)O2, (23.1±2.8) mmHg vs. (16.5±2.4) mmHg mmHg], pulmonary artery systolic pressure [PASP, (54.6±7.9) mmHg vs. (34.2±7.5) mmHg] in thrombolysis group, P<0.05 or <0.01. Total effective rate of thrombolysis group (100%) was significantly higher than that of pure anticoagulation group (80.6%), P=0.002. There were no significant difference in incidence rates of bleeding and thrombocytopenia between two groups, P>0.05. Conclusion:　Thrombolysis therapy can significantly lower pulmonary artery pressure and improve oxygenation and right ventricular function indexes in patients with acute submassive pulmonary embolism. It may be a preferred recommendation for patients without contraindications.

The contour line of human brain was simulated by the curve-fitting methods and then the inner area was discretized by advancing-front methods which was improved at last. The curve-fitting result was similar to the CT picture of the human brain and the discrete result of inner area could be completed quickly by improved advanced-front methods. A finite element model with the contour line of human brain was built primarily which will contribute to the next algorithm study of electrical impedance tomography in human brain.
Algorithms ; Brain ; anatomy & histology ; Finite Element Analysis ; Humans ; Models, Anatomic ; Models, Neurological