Objective:To investigate the influences of material properties and damping effect on the dynamic response analysis of human periodontal ligament. Methods: A 3-D finite element model of human teeth and periodontal tissue was built from graphic information obtained by CT scanning. Dynamic analysis was performed to investigate the influence of different damping effects on the stresses of periodontal ligament by the finite element method. Results: (a) No significant difference of stress between small and large deformation assumption was found, the variation was no more than 1.4%.(b) Dynamic response was obtained under ? varies from 0 to 1.2. After one mastication period, the residual stress at interior surface was larger than that at exterior surface, with a maximum value of ? r = 0.34 MPa at labial cervical area. Conclusion: Appropriate assumptions on material properties may reduce the cost of analysis. After one mastication period, some levels of residual stresses are in periodontal ligament and influenced by material damp.

Objective:To improve stress analysis in stress-intensive regions of human periodontal tissue. Methods:Based on coarse analysis on the finite element(FE) model including human teeth and periodontal tissue, the submodel method was introduced to analyze the stresses in interested region such as apical. Results:Submodel analysis showed same stress distribution as FE model while more precision of stress value was obtained by submodel because refined mesh was used.Conclusion:More accurate stresses measurements in local regions can be obtained by submodel method.

Based on Chinese clinical guidance for COVID-19 pneumonia diagnosis and treatment (7^th edition), the metabolism and pharmacokinetics of drugs used in clinical treatment of COVID-19 were reviewed. The antiviral drugs include remdesivir, chloroquine/hydroxychloroquine, lopinavir/ritonavir, favipiravir, arbidol, baicalin, baicalein and forsythin. Among them, the metabolism and pharmacokinetics of arbidol, baicalin and forsythin are the research results of the author's laboratory. This article aims to provide reference for the efficacy evaluation and rational drug use of COVID-19.

Aortic Valve ; pathology ; Calcinosis ; Heart Defects, Congenital ; pathology ; Heart Valve Diseases ; pathology ; Humans

Objective To analyze the correlation between quantitative evaluation of high-resolution CT (HRCT) and pulmonary function tests (PFT) in chronic obstructive pulmonary disease (COPD), and evaluate the characteristics of PFT in different CT phenotypes of COPD. Methods 65 patients with COPD underwent CT chest scan and PFT. The dimensions of subsubsegmental apical bronchi of right upper lobes were measured , which included the following parameters:airway wall thickness (T), total airway diameter (D), and pulmonary artery (PA), ratio of airway wall thickness and pulmonary artery (T/PA), thickness diameter ratio (TDR), percentage of wall area (WA%) and percentage of airway luminal area (Ai%). The percentage of total lung area occupied by low attenuation area (LAA%) was measured by lung density software. The relationship between the measurements and PFT parameters were analyzed. Patients were classified into three phenotypes based on the presence of emphysema or bronchial wall thickening evaluated by HRCT. Phenotype A: without or with little emphysema (LAA% < 25%), with or without bronchial wall thickening; Phenotype E: emphysema without bronchial wall thickening (LAA%≥25%, T/PA < 30%); Phenotype M: emphysema with bronchial wall thickening (LAA%≥25%, T/PA≥30%). The characteristics of different CT phenotypes were analyzed. Results LAA% had a good correlation with PFT parameters. PA, T/PA, WA% and Ai% also had correlation with PFT parameters. There was 53 patients of Phenotype A, 12 patients of Phenotype M. PA, T/PA, LAA%and PFT were different in two groups. Conclusions LAA%and airway quantitative measurements in HRCT have certain correlation with PFT parameters. Patients with different CT phenotypes differs in PFT parameters , which can provide reference for clinical diagnosis and treatment.

Objective: To reconstruct adenovirus vector of breast eukaryotic initiation factor 4E and to observe its effect on the metastasis ability of breast cancer cell line MCF-7. Methods: eIF-4E gene was constructed into adenovirus vector pAD-X by gene recombination technique, which was transformed into 293 packaged cell for high titer adenovirus. Real-time PCR was applied to detect eIF-4E gene expression. eIF-4E siRNA was applied and then transwell cabin assay was used to observe changes of invasion and motor ability of MCF-7 cells transfected with reconstruction adenovirus. Result:The finding of digestion was coincided with expected. eIF-4E gene over-expression was detected in transfected MCF-7 cells with real-time PCR. And the invasion and motor abilities of transfected MCF-7 cells were more significantly inhibited in transwell cabin assay (respectively p

Objective To compare the outcomes of traumatic flail chest with multiple injuries treated by operative fixation versus conservative approach. Methods The clinical data of 60 patients with traumatic flail chest with multiple injuries were retrospectively analysed, and the outcomes between operation group (treated by operative fixation, n=32)and non-operation group (treated by conservative approach, n=28) were compared. Results The mean time of hospital stay, ICU stay and mechanical ventilation was significantly shorter, and the prevalences of chest wall deformity, pulmonary infection, pulmonary atelectasis and respiratory failure were significantly lower in operation group than those in non-operation group (P<0.05). Six months after discharge, the pulmonary function parameters such as inspiratory capacity, forced vital capacity, forced expiratory volume in one second, peak expiratory flow, total lung capacity and maximal midexpiratory flow were significantly higher in operation group than those in non-operation group (P<0.05). Conclusion Traumatic flail chest with multiple injuries treated by operative fixation may lead to less flail chest associated complications. Operative fixation has short- and long-term benefits to flail chest.

Objective To assess the clinical efficiency , safety and potential advantages of autologous blood transfusion (ABT) drains compared with the closed-suction/no drainage. Methods Pubmed, Embase, Cochrane Library, CBMdisc, CNKI, VIP and WANGFANG were searched comprehensively. The statistical anal-ysis was conducted by using the Cochrane Collaboration review Manager 5.3.5. Results The pooled data of seventeen RCTs including a total of 1 993 patients showed that the patients in the ABT drainage group might benefit from the low rate of blood transfusion [ 16 . 59% and 37 . 47%, OR: 0 . 28 ( 0 . 14 ~ 0 . 55 ); 13 . 05% and 16.91%, OR: 0.73 (0.47 ~ 1.13), respectively]. The ABT drainage and the closed-suction drainage/no drainage have the similar clinical efficiency and safety length of hospital stay and wound infection on days 3 post-operative haemoglobin. Conclusion This systematic review provides the evidence that the ABT drainage offers a safe and efficient alternative to CS/no drainage with the lowered blood transfusion rate.

Aged, 80 and over ; Heart Valve Prosthesis Implantation ; methods ; Humans ; Male ; Prosthesis Failure

The study aims to develop a rapid, sensitive and specified method of liquid chromatography with heated electrospray ionization tandem mass spectrometry (LC-HESI/MS/MS) for simultaneous determination of amlodipine, benazepril and benazeprilat in human plasma using amlodipine-d4 and ubenimex as internal standards (ISs). Selected reaction monitoring (SRM) with heated electrospray ionization (HESI) was used in the positive mode for mass spectrometric detection. Analytes and ISs were extracted from plasma by simple protein precipitation. The reconstituted samples were chromatographed on a C18 (100 mm x 4.6 mm, 5 microm) column with mixture of methanol-acetonitrile-5 mmol.L- ammonium acetate-formic acid (30 : 30 : 40 : 0.1) as mobile phase at a flow rate of 0.6 mL.min-1. The standard curves were demonstrated to be linear in the range of 0.02 to 6.00 ng.mL-1 for amlodipine, 0.2 to 1,500 ng.mL-1 for benazepril and benazeprilat with r2>0.99 for each analyte. The lower limit of quantitation was identifiable and reproducible at 0.02, 0.2 and 0.2 ng mL-1 for amlodipine, benazepril and benazeprilat, respectively. The intra-day and inter-day precision and accuracy results were within the acceptable limit across all concentrations. The plasma samples were stable after four freeze-thaw cycles and being stored for 93 days at -20 degrees C. The method was applied to a pharmacokinetic study of a fixed-dose combination of amlodipine and benazepril on Chinese healthy volunteers.
Administration, Oral ; Amlodipine ; administration & dosage ; blood ; Benzazepines ; administration & dosage ; blood ; Chromatography, Liquid ; Humans ; Sensitivity and Specificity ; Spectrometry, Mass, Electrospray Ionization ; Tandem Mass Spectrometry