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In order to prevent the teaching reform of organ system curriculum from fall of teaching quality, the teaching effect of organ system curriculum and subject curriculum system in teaching the basic knowledge of pathophysiology was compared. In organ system curriculum teaching, there was no difference between the grades of students in Batch 2011 and Batch 2012 who conformed to the teaching principle of "gradual improvement" and those of the students taught with subject curriculum system. On the contrary, the students of Batch 2013 and Batch 2014 with insufficient curriculum content integration had a decreasing trend or a significant reduction in the teaching effect of organ system curriculum compared with that of subject curriculum system. After the supplementary for curriculum knowledge was made, the teaching effect of the organ system was significantly improved, which was better than that of the subject curriculum system. In conclusion, we have summarized and reflected on the effectiveness of the teaching reform of organ system curriculum, once again proved that basic medical teaching must also follow the inherent law of medical education, which is the teaching principle of "gradual improvement."
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Tooth contour segmentation from dental computerized tomography (CT) images is one of the fundamental steps in reconstructing the three-dimensional models of teeth. However, existing methods depend on the tooth shape similarity between adjacent slices, and have difficulty to segment these angled teeth whose contour shapes from adjacent slices may differ a lot. This study proposes a new method for contour segmentation of angled teeth from CT images. The volume of interest (VOI) of target tooth and corresponding tooth axis are first extracted from volumetric CT images. Local images within the VOI of target tooth are then rotated such that the tooth axis in the rotated images is perpendicular to the transverse section. Tooth contours are finally segmented from the rotated images using a hybrid level set model slice-by-slice. Experimental results verified that the proposed method was effective to segment contours of angled teeth from CT images.
Subject(s)
Tooth , Algorithms , Cone-Beam Computed Tomography , Imaging, Three-Dimensional , Tomography, X-Ray ComputedABSTRACT
Estimation of tooth axis is needed for some clinical dental treatment. Existing methods require to segment the tooth volume from Computed Tomography (CT) images, and then estimate the axis from the tooth volume. However, they may fail during estimating molar axis due to that the tooth segmentation from CT images is challenging and current segmentation methods may get poor segmentation results especially for these molars with angle which will result in the failure of axis estimation. To resolve this problem, this paper proposes a new method for molar axis estimation from CT images. The key innovation point is that: instead of estimating the 3D axis of each molar from the segmented volume, the method estimates the 3D axis from two projection images. The method includes three steps. (1) The 3D images of each molar are projected to two 2D image planes. (2) The molar contour are segmented and the contour's 2D axis are extracted in each 2D projection image. Principal Component Analysis (PCA) and a modified symmetry axis detection algorithm are employed to extract the 2D axis from the segmented molar contour. (3) A 3D molar axis is obtained by combining the two 2D axes. Experimental results verified that the proposed method was effective to estimate the axis of molar from CT images.
Subject(s)
Imaging, Three-Dimensional/methods , Molar/diagnostic imaging , Tomography, X-Ray Computed/methods , Algorithms , Cone-Beam Computed Tomography/methods , Humans , Principal Component AnalysisABSTRACT
Orthodontic force simulation is very important for the guidance of clinical orthodontic treatment. Previous works were mainly conducted by directly loading the force on a single or a few teeth. However, in clinic, the orthodontic force is provided by loading orthodontic appliances, and there currently is no appropriate way to measure the force on the teeth provided by the loaded appliances. This study presents a method to simulate the orthodontic force of a whole Tooth-Periodontal Ligament-Bone Complex (TPBC) by directly loading the archwire to the dentition applying the finite element method. A 3D TPBC model was reconstructed from CT images, and models of brackets and the archwire were also built. The loading procedure of the archwire was implemented by simulating the deformation and displacement of the archwire before and after the loading, and the stress of the archwire induced by the deformation and displacement was obtained. Then, the stress was applied to the brackets, and the corresponding orthodontic force of the TPBC was simulated. By applying the method, archwire designed according to the planned dentition shape was loaded successfully to the original dentition, and the orthodontic force of the TPBC was obtained.
Subject(s)
Models, Dental , Orthodontic Appliances , Periodontal Ligament/physiology , Tooth/physiology , Humans , Stress, MechanicalABSTRACT
Objective:To evaluate the influence of cervical collar height on the compressive strength of CAD/CAMzirconia-ceramic restoration.Methods:Zirconia cores were manufactured and divided into 5 groups (n =1 0)based on the cervical collar height(mm):0.0(A),1 .0(B),1 .5(C),2.0(D)and 2.5(E).After veneered with porcelain,all the samples were cemented on the metal tooth analog and then mounted in an universal test machine.The force was applied at a crosshead speed of 1 mm/min until catastrophic fail-ure occurred.Fracture loads and failure modes were recorded.Results:Mean of the fracture strength values(kN)in group A,B,C, D and E were 0.95 ±0.39,1 .29 ±0.50,1 .54 ±0.28,2.04 ±0.1 9 and 2.27 ±0.53 respectively(among groups,P <0.05).Two types of fracture modes were observed:chipping of the veneering porcelain and fracture of the veneering porcelain together with the framework.Conclusion:Zirconia coping design with 1 .5 mm cervical collar height may increase the compressive strength of CAD/CAMzirconia-ceramic restoration.
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Objective To elucidate the mechanism of radiation resistant effect of LyGDI on NSCLC A549 cells.Methods A549 and H460 cells were irradiated with X-rays of 0,2,4 and 6 Gy.The clone-forming assay was used to detect cell survival and radiosensitivity.The expressions of LyGDI and COX-2 (Cyclooxygenase-2),a key radiosensitivity-related protein,were detected using Western blot.The miR-34 families were analyzed with RT-PCR.50 nmol/L mature miR-34c was transfected into A549 cells.Results The expression levels of LyGDI and COX-2 were much higher in radioresistive A549 cells than that in H460 cells.While the expression of miR-34a was quite low and miR-34b/c was hardly found in both NSCLC cells.Transfection of miR-34c into A549 cells strongly enhanced X-ray induced apoptosis by inhibiting the activations of LyGDI,COX-2,Bcl-2 and p21.Conclusions Up-regulation of LyGDI could induce COX-2 expression.The low expression of miR-34 family might be responsible for the radiation resistance of NSCLC cells.
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Objective To study the technique in isolating the retrohepatic inferior vena cava in right hepatectomy.Methods Anatomical exposure of the right lateral wall of retrohepatic inferior vena cava was performed,followed by isolating its back wall.Results Part of the right liver was rotated out of the incision.The 77 patients recovered smoothly.Conclusion Dividing the right adrenal is the key to free the retrohepatic inferior vena cava.To expose the right side of the retrohepatic inferior vena cava is a standard technique to mobilize the right liver.
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Objective To elucidate the function and regulatory mechanism of LyGDI involved delayed cell death in the human K562 cells and HL-60 cells induced by 60Co γ-rays. Methods Erythrosine B cells staining was used to count the apoptosis rate. PI staining and flow cytometry were applied to check the cell cycle. The expression of LYGDI and Rac1 was resolved by Western blot by using monoclonal antibody of LyGDI and Racl. The distribution of Racl protein in cells was observed with immunofluorescence by using the confocal microscope. Results The K562 cells showed G2/M phase arrest and the percent age was 71.3%. The apoptosis rate was very low at early post-irradiation stage in the K562 cells. The apoptosis rate was 14% in the K562 cells at 24 h post-irradiation with 8 Gy of γ-rays, and delayed cell apoptosis was present. LyGDI was cleaved in the K562 cells irradiated by 4 Gy 60 Co γ-rays after 24 hours post-irradiation. The expression of Racl protein was not altered at all, but the distribution was changed in the irradiated cells while the Racl protein moved to cell membrane and a little in cell nucleus. The Racl was activated with the losing the binding affinity with the LyGDI. Conclusion LyGDI could promote the delayed cell apoptosis, which is through the activation of the Rac1.
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To study the prevention of dauricine (Dau) on bradykinin (BK) induced alteration of intracellular calcium homeostasis and tau phosphorylation, fluorescence spectrophotometer with dual excitation was utilized to measure the intracellular calcium concentration ([Ca2+]i), MTT to detect cell viability and immuncytochemistry to examine tau phosphorylation. The results showed (1) cells treated with BK 1 μmol/L induced a transit increase in [Ca2+]i in all the cell lines detected, among them, the sustained increase of [Ca2+]i level was only seen in PS1Δ9/APPswe cell at 2 h and 24 h after the treatment. Dau (3μmol/L or 6 μmol/L) prevented BK-induced transit and sustained elevation and fluctuation of [Ca2+]i;(2) BK treatment decreased the cell metabolism detected at 2 h in PS1Δ9/APPswe and Dau antagonized the effect; (3) BK induces Alzheimer-like tau hyperphosphorylation at tau-1 epitope and Dau partially antagonized this effect. In conclusion,Dau inhibits BK-induced disturbance in intracellular calcium homeostasis and tau hyperphosphorylation at tau-1 sites.
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Objective For establishing a effective method of gene polymorphism. Methods Polymorphism of CYP1A1 were detected by allele specific amplification and allele specific amplification-ELISA in this study.Results The results of two testing methods were same except one sample.PCR products were labeled with Dig in ASA-ELISA,then the PCR products were detected by specific and sensitive ELISA.The assay detection was 100-fold more sensitive than gel detection of ASA PCR products.Conclusion It was simple and short time,but it was more expensive.
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AIM: To explore the effect of receptor tyrosine kinase system mediated by phosphotyrosine phosphatase (PTP) on tau phosphorylation in rat hippocampus. METHODS: Pervanadate (PVN), inhibitor of PTP or inhibitor of glycogen synthase kinase-3 (GSK-3), LiCl were injected into rat hippocampus by stereotaxy technique. The level of tau phosphorylation was detected by Western blot and immunohistochemistry after 24 h of injection. RESULTS: PVN significantly inhibited tau phosphorylation at PHF-1 epitope and the inhibition of tau phosphorylation by PVN was stronger than that of LiCl (P
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AIM: To investigate the effects of intracellular free calcium ([Ca 2+ ]i) from different resources on the proliferation mediated by mitogen activated protein kinase (MAPK) in vascular smooth muscle cells (VSMCs). METHODS: Cultured VSMCs were used in all experiments. Calcium influx was stimulated by angiotension Ⅱ(AngⅡ). The release of intracellular calcium stores was induced by inositol trisphosphate(IP 3) and ryanodine(RY). MAPK activity was measured by [?- 32 P]-ATP incorporation , MAPK protein expression by western blot, VSMCs proliferation by -Leucine(-Leu) and -Thymidine(-TdR) incorporation. RESULTS: Compared to the control VSMCs, AngⅡ, IP 3 and RY significantly increased [Ca 2+ ]i concentration , activity of MAPK and its protein content in VSMCs. The promotion of -Leu and -TdR incorporation in VSMCs was also observed ( P
