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.Effects of neonatal repeated intermittent inhalation of sevoflurane on learning-memory and Tau protein, p-Tau protein in juvenile and adult rats
Quan WANG ; Chao ZHANG ; Yi WANG ; Zhaoqiong ZHU
Journal of Medical Postgraduates 2017;30(3):257-261
Objective Learning and memory function is the form of brain higher nervous activity .Hippocampus is the main parts responsible for learning and memory function .Once damaged , it will seriously affect the quality of life in patients .The purpose of this paper was to observe the effects of neonatal repeated intermittent sevoflurane inhalation on learning-memory function and Tau protein , p-Tau protein in brain hippocampus in juvenile and adult rats . Methods Twenty-four healthy SD rats ( n=24 ) were randomly di-vided into juvenile sevoflurane inhalation group ( n=6) , juvenile con-trol group ( n=6);adult sevoflurane inhalation group ( n=6) , and adult control group ( n=6) .Rats in juvenile sevoflurane inhalation group and adult sevoflurane inhalation group inhaled 2.6%sevoflurane at the postnatal 7th day, 14th day, 21th day ( P7,P14,P21) for 2 hours.Rats in juvenile control group and adult control group inhaled the carrier gas (1L/min Air+1L/min O2) at the same time for 2 hours.During P31~37, Morris water maze test was conducted in juvenile sevoflurane inhalation group and juvenile control group to detect the behavior.During P91~97, Morris water maze test was conducted in adult sevoflurane inhalation group and adult control group to detect the behavior .Then hippocampi were taken out to detect the expression levels of Tau protein and p -Tau protein. Results ( 1) Comparison of escape latency at the same time ① Juvenile period: no statistical difference between sevoflurane inhalation group (52.04±41.90,29.77±14.23, 19.87±5.71,22.74±13.73,21.91±9.07) and control group (47.82±8.06,25.26±12.53,23.79±9.49, 20.00±10.10, 14.03±7.55) had (P>0.05).② Adult period: no statistical difference between sevoflurane inhalation group (42.00± 14.12, 26.87±16.93, 19.80±13.76, 15.06±8.45, 8.66±4.82) and control group (41.97±25.66,22.88±10.04,15.88±5.20,9.26± 3.98,11.33±6.05 (P>0.05).(2) Comparison of spatial probe test results:no statistical difference in the swimming times from original area,swimmingresidencetime,swimmingdistanceandspeedbetweengroups(P>0.05).(3)Tauproteinexpressiondetection ①Juvenile period:In the hippocampal CA1 region, CA3 region, DG region, the expression level of Tau in the sevoflurane inhalation group (0.237±0.015, 0.324±0.024,0.226±0.019) was higher than the control group (0.185±0.024,0.232±0.040, 0.184±0.018) (P>0.01).②Adult peroid:no statistically significant difference between sevoflurane inhalation group and control group (P>0.05). (4)p-Tau(Ser396)proteinexpressiondetection ①Juvenileperiod:nostatisticallysignificantdifferencebetweensevofluraneinhala-tion group and control group ( P>0.05) .②Adult period:The expression level in the hippocampal CA3 region of sevoflurane inhalation group (0.170±0.005) was higher than control group (0.158±0.011) (P<0.05), but in the CA1 and DG regions there was no statisti-cally significant difference (P>0.05). Conclusion Neonatal repeated intermittent sevoflurane inhalation has done no harm to learn-ing and memory function of juvenile and adult rats , however , it can result in the significant increase of hippocampal Tau protein expres-sion level in juvenile rats and the increase of hippocampal p-Tau protein expression level in adult rats .
5.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.
6.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.
7.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.
8.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.
9.Clinical analysis of 41 cases of Hashimoto's disease accompanying with thyroid cancer
Zhipeng ZHANG ; Yi XIA ; Huijun LIAO ; Chao DONG ; Shi CHANG
Journal of Endocrine Surgery 2013;7(4):281-283
Objective To analyze the clinical characteristics of Hashimoto's disease(HD) accompanying with thyroid cancer,and to explore the experience of diagnosis and treatment.Methods Clinical data of 41 cases of HD accompanying with thyroid cancer were retrospectively analyzed.The patients were diagnosed by postoperative paraffin pathological examination from Jan.2002 to July 2011.Results 10 cases of HD,37cases of thyroid cancer,and 8 cases HD accompanying with thyroid cancer were diagnosed before operation.The rate of preoperative diagnosis was only 19.51%.All patients underwent surgical treatment,including 22 cases total thyroidectomy,14 cases subtotal thyroidectomy,and 5 cases lesion side lobe resection.24 cases underwent ipsilateral neck dissection,and 4 cases underwent bilateral neck dissection (ipsilateral radical resection,contralateral selective resection).Postoperative paraffin pathological examination proved that there were 39 cases of HD accompanying with thyroid cancer,1 case of focal cancer and 1 case of B-cell lymphoma of mucosa-associated thyroid.All patients were followed up.Conclusions The preoperative diagnosis rate of HD accompanying with thyroid cancer is low and great attention should be paid to its diagnosis.For HD patients,if carcinoma can not be excluded,surgical exploration is recommended.Appropriate surgical method should be chosen according to intraoperative frozen section results.Postoperative thyroid hormone treatment is usually taken.
10.Effects of neonatal repeated inha lation of sevoflurane on ability of learning and memory and hippocampal volume in infantile rats
Juanjuan REN ; Zhaoqiong ZHU ; Yi WANG ; Chunchun TANG ; Chao ZHANG
Journal of Medical Postgraduates 2016;29(5):470-474
Obj cetive A large number of recent studies show that sevoflurane anesthesia may cause learning and memory dysfunction.The aim of this study was to explore changes of learning and memory ability and hippocampal volume in infantile rats after neonatal interrupted and repeated inhalation of 2.6% sevoflurane through detecting the learning and memory ability by Morris water maze and the hippocampus volume by MRI.Method s Thirty two neonatal SD rats were randomly devided into two groups (n=16):experimental group and control group.Rats inhalated 2.6%sevoflurane in the experimental group and 1 L/min O2 +1 L/min Air in the control group at the postnatal days of 7, 14 and 21 (P7, P14, P21). The learning and memory ability was determined by the Morris water maze test from P31 to P37;The brains of rats were scanned by mag-netic resonance imaging ( MRI) machine under anesthesia with 1%sodium pentobarbital at P37, and the brain and bilateral hippocampal volumes were measured. Results ①In the place navigation test, the escape latency had no significant difference between the two groups (P>0.05).In the spatial probe test, the dwelling time, movement distance and number of entering times in platform quadrant decreased slightly in experimental group compared with those in the control group, while there was no significant difference (P>0.05).②The brain volume [(1.53 ±0.18) cm3 vs (1.60 ±0.13) cm3] and right hippocampal volume [(16.15 ±1.76)mm3 vs(16.46 ±1.71)mm3] had no significant difference between the two groups (P>0.05).The left hippocampal volume [(16.46 ±1.71)mm3] was decreased in the experimental group compared with the control group [(18.10 ±2.53)mm3](P<0.05). Conclusion The learning and memory ability has no significant changes in in-fantile rats after neonatal interrupted and repeated sevoflurane inhalation and MRI examination of hippocampal volume is not sufficient for the diagnosis of cognitive dysfunction.