3.Three-dimensional finite element analysis of maxillary anterior teeth retraction force system in light wire technique.
Xiangfeng ZHANG ; Chao WANG ; Xi XIA ; Feng DENG ; Yi ZHANG
West China Journal of Stomatology 2015;33(3):291-295
OBJECTIVEThis study aims to construct a three-dimensional finite element model of a maxillary anterior teeth retraction force system in light wire technique and to investigate the difference of hydrostatic pressure and initial displacement of upper anterior teeth under different torque values of tip back bend.
METHODSA geometric three-dimensional model of the maxillary bone, including all the upper teeth, was achieved via CT scan. To construct the force model system, lingual brackets and wire were constructed by using the Solidworks. Brackets software, and wire were assembled to the teeth. ANASYS was used to calculate the hydrostatic pressure and the initial displacement of maxillary anterior teeth under different tip-back bend moments of 15, 30, 45, 60, and 75 Nmm when the class II elastic force was 0.556 N.
RESULTSHydrostatic pressure was concentrated in the root apices and cervical margin of upper anterior teeth. Distal tipping and relative intrusive displacement were observed. The hydrostatic pressure and initial displacement of upper canine were greater than in the central and lateral incisors. This hydrostatic pressure and initial intrusive displacement increased with an increase in tip-back bend moment.
CONCLUSIONLingual retraction force system of maxillary anterior teeth in light wire technique can be applied safely and controllably. The type and quantity of teeth movement can be controlled by the alteration of tip-back bend moment.
Finite Element Analysis ; Humans ; Incisor ; Maxilla ; Tooth Movement Techniques ; methods ; Tooth Root ; Torque
4.Advances in studies on growth metabolism and response mechanisms of medicinal plants under drought stress.
Can SI ; Jun-Yi ZHANG ; Hu-Chao XU
China Journal of Chinese Materia Medica 2014;39(13):2432-2437
Drought stress exerts a considerable effect on growth, physiology and secondary metabolisms of the medicinal plants. It could inhabit the growth of the medicinal plants but promote secretion of secondary metabolites. Other researches indicated that the medicinal plants could depend on the ABA signaling pathway and secreting osmotic substances to resist the drought stress and reduce the damage by it. The article concludes the changes in growth, physiology, secondary metabolisms and response mechanisms of medicinal plants to drought stress that provides a theoretical basis for exploring the relationship between medicinal plants and drought stress.
Abscisic Acid
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metabolism
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Droughts
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Plant Proteins
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genetics
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metabolism
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Plants, Medicinal
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genetics
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growth & development
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metabolism
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Signal Transduction
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Water
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metabolism
5.Correlation studies on tuberculosis patient′s self-efficacy and coping style
Lijun HUANG ; Chao WANG ; Yi XIE ; Wenxin ZHANG ; Yang LI
Chinese Journal of Practical Nursing 2017;33(13):964-969
Objective To describe the status of the self-efficacy and coping styles of tuberculosis patients,analysis the relationship between self-efficacy and coping styles. Methods With the method of convenient sampling, used the general information questionnaire self-designed, General Self-Efficacy Scale (GSES) and Medical Coping Modes Questionnaire (MCMQ) to take questionnaire survey on 132 patients with pulmonary tuberculosis.Applicated SPSS19.0 software for the statistics, and analyzed the relationship between self-efficacy and coping styles on patients with pulmonary tuberculosis. Results The mean score of self-efficacy in 132 pulmonary tuberculosis patients was 24.90 ± 7.04,which was in the medium to low level. The proportion of mediun,lower,higher level of self-efficacy was 44.70% (59/132), 39.40%(52/132),15.90%(21/132).Scores of the coping styles on face,avoid, yield were 21.16±9.23,16.55± 2.83,9.68 ± 4.12.Patients self-efficacy level was positively correlated with face coping style (r=0.242, P<0.05), avoid coping style (r=0.150, P<0.05),and negatively correlated with the yield response (r=-0.008, P<0.05). Conclusions The general self-efficacy level of tuberculosis patients is at a lower level. Tuberculosis patients should have more choice to handle it.
6.In vivo killing effects of nanosecond pulsed electric fields on mouse breast cancer
Yi LIU ; Zhixiao XUE ; Chao WANG ; Haixia ZHANG ; Donghao LV
International Journal of Biomedical Engineering 2015;(3):165-167,171
Objective To explore the in vivo killing effects of nanosecond pulsed electric fields on mouse breast cancer in tumor bearing BALB/c mice. Methods Twenty four BALB/c mice models with subcutaneous EMT-6 breast cancer were prepared and divided into experimental group and control group (n=12). In experimental group, the mice were treated by the pulsed electric fields with peak voltage of 700 V/cm, rise times of 57 ns, durations of 70μs and duty ratio of 50%on the tumor tissue with two parallel electrodes under anaesthesia. One hundred pulses were given and the energy was just 9.75 J with effective action period of 7 ms. Tumor volume, animal weight and histopathologic changes after 1, 3, 5 and 7 d were observed after irreversible electroporation. Results The tumor volume in experimental group increased more slowly than that in control group, especially at the 1-3 d after treatment with a standstill. Histopathological examination results showed that the tumor tissue had obvious coagulation necrosis and tissue edema after electrical stimulation treatment, and mass vacuole like structure appeared in tumor tissue from the third day after treatment and vascular injury occurred at the early stage. Conclusions In the given field conditions, steep pulsed electric field has inhibitory effect on tumor growth. In order to achieve more ideal tumor therapy effect, further studies on steep pulse dose are needed.
7.Morphological changes of enteric deep muscular plexuses interstitial cells of Cajal in rats with multiple organ disfunction syndrome
Yi LI ; Qinghui QI ; Chao YU ; Dongliang ZHANG ; Weiming ZHU
Parenteral & Enteral Nutrition 2009;16(6):338-342
Objective: To observe the morphological changes of enteric deep muscular plexuses interstitial cells of Cajal (ICC-DMP) in rats with multiple organ dysfunction syndrome (MODS). Methods: Forty Wistar rats were randomly divided into control group and MODS model group. The enteric ICC-DMP network was observed using c-kit immunohistochemical staining with whole-mount preparation technique and confocal laser scanning microscopy , and the ultraslructural features of ICC-DMP was evaluated using transmission electron microscope. Results: Compared with those in control group, the distributions and densities of intestine ICC-DMP in MODS group were significantly decreased (P < 0. 05) , the ICC-DMP network was disrupted and the ultrastructural features of ICC-DMP were severely damaged. Conclusion: The ICC-DMP network was severely damaged in rats with MODS, and the mechanism of gastrointestinal dysmotility in MODS may be related to the morphological changes of ICC-DMP.
8.Expression of AKT2 gene in human liver cancer and its clinical significance
Yi XIE ; Xin CHEN ; Haixin QIAN ; Wanghe WANG ; Chao ZHANG
Chinese Journal of Hepatobiliary Surgery 2012;18(1):34-36
ObjectiveTo study the expression of AKT2 gene in liver cancer and its relationship to tumor progression.MethodsThe expression of AKT2 in liver cancer was detected by SP immunohistochemical stainin and reverse transcription polymerase chain reaction (RT-PCR).Four patients with benign liver tumors were used as control.ResultsThe positive rates of AKT2 in liver cancer tissue and benign control tissue were 62.5% (28/32) and 0% (0/4),respectively.The difference was significant.In addition,a positive expression of AKT2 correlated significantly with poor differentiation,positive lymph node and distant metastasis.The median survival after surgery was significantly shorter in patients with positive than with negative AKT2 (76d vs 463d).ConclusionThe detection of AKT2 was useful in assessing the progression of liver cancer,in determining prognosis and eventually in rendering a possible target for novel therapeutic strategies.
10.Genetic diversity of different populations of lilyturf revealed by RSAP analysis.
Hu-Chao XU ; Jun-Yi ZHANG ; Can SI
China Journal of Chinese Materia Medica 2014;39(20):3922-3927
Restriction site amplification polymorphism (RSAP) markers were employed to access the genetic diversity and relationship of 120 lilyturf germplasms from different geographical origins. Sixteen RSAP primer pairs generated 326 polymorphic bands, of which 318 (97.55%) were polymorphic. The value of polymorphism information content (PIC) ranged from 0.87 to 0.95 with an average of 0.92. These results indicated there was abundant genetic diversity among samples. The results of data analysis on 20 population showed that the value of percentage of polymorphic locus (PPL), Nei's gene diversity (H) and Shannon's information index (I) were 19.94%-85.58%, 0.082 6-0.210 7, 0.120 6-0.328 1 respectively. The most abundant genetic diversity was found in the O. japonicus population from Zhejiang and the least in the Liriope minor population. The genetic distance among 20 population was 0.024 6-0.286 8, of which the minimum genetic distance was 0.024 6 between population I and population 13 while the maximum 0.286 8 between population 5 and population 15. Coefficient of genetic differentiation among natural populations was 0.115 3 (Gst). And the gene differentiation contributed to 43.07% of the total genetic variation among populations and to 56.93% within populations. The total gene flow (Nm) was 0.660 9. UPMGA clustering analysis was basically similar to of the principle coordinate analysis (PCA). The 120 samples were classified into four major groups, which were basically corresponded with the genetic relationships based on morphological traits. The results of UPMGA and PCA were also consistent with geographical origins.
Amplified Fragment Length Polymorphism Analysis
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China
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Genetic Variation
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Liriope Plant
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classification
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genetics
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Phylogeny
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Polymorphism, Restriction Fragment Length