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1.
Chinese Journal of Stomatology ; (12): 244-250, 2023.
مقالة ي صينى | WPRIM | ID: wpr-970782

الملخص

Objective: To explore the diagnostic value of p16/Ki-67 double-stained immunohistochemistry in the diagnosis of human papilloma virus (HPV)-positive oropharyngeal squamous cell carcinoma(opscc) and find out the optimal index to improve the accuracy of HPV detection. Methods: A total of 153 cases, from May 2014 to May 2020, diagnosed OPSCC in Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, were selected. This cohort included 130 males and 23 females, aged (58.6±10.0) years old. HPV RNA in situ hybridization was chosen as the gold standard to detect their HPV status. p16 immunohistochemistry and p16/Ki-67 double-stained immunohistochemistry were performed on all cases, and the p16/Ki-67 double positive index including 20%, 40%, and 60% were used as the thresholds to compare their sensitivity, specificity, and positive prediction value (PPV), negative prediction value (NPV) and prognosis prediction ability. Results: Among the 153 patients with OPSCC, 114 were HPV-negative and 39 were HPV-positive, and the HPV infection rate of OPSCC patients was 25.5% (39/153). Only 58.1% (36/62) of single p16 positive cases were HPV-positive, and the prognosis of patients could not be distinguished using p16 immunohistochemistry only. Using p16/Ki-67 double staining, the accuracy of HPV positive diagnosis has been improved. The HPV diagnostic ability was the highest when the p16/Ki-67 double positive index was 40% (sensitivity=86.8%, specificity=94.8%, PPV=84.6%, NPV=95.6%, area under the curve=0.897), which could distinguish the prognosis of patients (P=0.012). Conclusions: The p16/Ki-67 double-stained immunohistochemistry can improve the accuracy of HPV positive diagnosis rate and diagnosis of HPV-positive oropharyngeal cancer is the most accurate when the double-positive index is 40% as the threshold to judge HPV status and could serve as better surrogate marker for HPV detection.

2.
Yao Xue Xue Bao ; (12): 1894-1903, 2023.
مقالة ي صينى | WPRIM | ID: wpr-978663

الملخص

In this study, we investigated the anti-osteoporotic activity and mechanism of action of extract of Panax quiquefolium L. based on zebrafish model combined with metabolomics technology. A zebrafish model of prednisolone-induced osteoporosis was used to compare the anti-osteoporotic activity of Panax quiquefolium L., and the expression of osteoblast-associated genes and osteoclast-associated genes in zebrafish was detected by quantitative real-time PCR (qRT-PCR), using bone fluorescence area and fluorescence density as evaluation indexes. Metabolomics based on ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS) was used to explore the change patterns of biomarkers and the metabolic pathways affected. The results showed that the 50% ethanol extracts of Panax quiquefolium L. from Jilin, Canada, Wenden and the United States can significantly improve the bone fluorescence area of zebrafish compared with model group. Furthermore, four sources 50% ethanol extracts of Panax quiquefolium L. except United States also can significantly improve the bone fluorescence density of zebrafish. In addition, PCR showed that extract of Panax quiquefolium L. can significantly up-regulated the expression of vitamin D receptor b (vdrb), collagen type I α2 (col1a2) and cysteine-rich acidic secreted protein (sparc) genes, and down-regulated the expression of matrix metalloproteinase 9 (mmp9), anti-tartrase acid phosphatase (trap) and cathepsin K (ctsk) genes. Metabolomic analysis identified 24 key differential metabolites. Furthermore, pathway analysis showed that Panax quiquefolium L. could regulate the levels of 10 key biomarkers by participating in purine metabolism, tricarboxylic acid cycle and pentose phosphate metabolism and improve the osteoporosis status of zebrafish. This study preliminically revealed the anti-osteoporosis mechanism of 50% ethanol extract from Panax quiquefolium L. through multi-component, multi-target and multi-pathway and also provides theoretical basis for clinical development and utilization of anti-osteoporosis products of Panax quiquefolium L. This experiment was approved by the Experimental Animal Welfare Ethics Committee of the Institute of Biology, Shandong Academy of Sciences (approval number: SWS20181002).

3.
Chinese Journal of School Health ; (12): 1156-1161, 2021.
مقالة ي صينى | WPRIM | ID: wpr-886608

الملخص

Objective@#To compare the effectiveness of three forms of health education including classroom teaching, network teaching and after class tutoring on exercise behavior among college students.@*Methods@#A literature search was performed using web of science, PubMed, ScienceDirect, Scopus, Cochrane Library, and CNKI database on randomized controlled trials of health education intervention on exercise behavior among college students. Literature filtering, data extraction, and assessment of the risks of bias were conducted by two independent researchers using Stata 16.0 software based on traditional Meta analysis and network meta analysis.@*Results@#A total of 23 literatures were included. The results showed that health education courses could effectively increase the weekly exercise time of college students( SMD =0.29), exercise frequency ( SMD =0.25) and number of students participating in exercise( OR =1.33). Subgroup analysis revealed that the increase in classroom teaching and network teaching associated with increased weekly exercise time ( SMD =0.45, 0.36), exercise frequency ( SMD =0.22, 0.37) and exercise number ( OR =1.36, 1.26)(all P <0.05); The effect of after class tutoring on the time and frequency of weekly exercise was not statistically significant( P >0.05). Indirect comparison showed that the effects of classroom teaching and network teaching on weekly exercise time, and exercise frequency were superior to that of extracurricular counselling( P <0.05); There were no significant differences in the weekly exercise time, frequency and number of participants between the two groups( P >0.05). Based on SUCRA method and the effect size, health education in the form of classroom teaching may have the greatest effect on the weekly exercise time, frequency and the number of students participating in the exercise( SUCRA =91.5, 94.1, 87.1).@*Conclusion@#Health education in the form of classroom teaching and network teaching can positively influence exercise behavior of college students.It is suggested that health education courses should be carried out in college courses so as to better promote college students to participate in physical exercise.

4.
مقالة ي صينى | WPRIM | ID: wpr-744577

الملخص

Objective To explore the effects of home exercise on sarcopenia obesity elderly.Methods From January to April, 2018, 80 patients with sarcopenia obesity were randomly divided into control group (CONG, n = 20), progressive resistance training group (PRTG, n = 20), aerobic exercise training group (ATG, n =20) and muscle strength combined with aerobic exercise training group (CTG, n = 20). The training groups accepted their exercise in home for eight weeks. Their body composition, muscle strength, and insulin-like growth factor 1 (IGF-1) and interleukin 6 (IL-6) in blood were measured before training, eight weeks and twelve weeks after training.Results Skeletal muscle mass increased in all the training groups compared with that of CONG after training, while fat mass, body mass index and visceral fat area reduced. Muscle strength increased in all the training groups compared with that of CONG after training, while the grip strength, knee extensor strength increased in PRTG and ATG. IGF-1 increased in PRTG and ATG, while IL-6 decreased in PRTG.Conclusion Home exercise can improve the body composition of patients with sarcopenia obesity elderly, as well as muscle strength, which may be related to increase of IGF-1 and decrease of IL-6.

5.
Zhongguo dangdai erke zazhi ; Zhongguo dangdai erke zazhi;(12): 383-386, 2018.
مقالة ي صينى | WPRIM | ID: wpr-689621

الملخص

<p><b>OBJECTIVE</b>To study the association between overweight/obesity in parents before maternal pregnancy and the development of autism spectrum disorders (ASD) in offspring.</p><p><b>METHODS</b>A total of 36 children who were diagnosed with ASD (ASD group) and 72 normal children matched for sex and age (control group) were enrolled. A questionnaire survey was performed to collect the general information, including body height and body weight of parents before maternal pregnancy and maternal weight gain during pregnancy. Univariate and multivariate logistic regression analyses were used to investigate the association between overweight/obesity in parents before maternal pregnancy and ASD in offspring.</p><p><b>RESULTS</b>The ASD group had a significantly higher detection rate of overweight/obesity in the father than the control group (56% vs 32%; P=0.018) before maternal pregnancy. The univariate and multivariate logistic regression analyses showed that overweight/obesity of the father before maternal pregnancy was a risk factor for ASD in offspring (OR=2.66 and 2.58 respectively; P<0.05).</p><p><b>CONCLUSIONS</b>Overweight/obesity of the father before maternal pregnancy is an independent risk factor for ASD in offspring, and therefore, it is important for the father to control his body mass index within the normal range before maternal pregnancy.</p>


الموضوعات
Child, Preschool , Female , Humans , Infant , Male , Autism Spectrum Disorder , Body Mass Index , Logistic Models , Obesity , Overweight , Parents , Risk Factors
6.
Zhongguo dangdai erke zazhi ; Zhongguo dangdai erke zazhi;(12): 994-1001, 2018.
مقالة ي صينى | WPRIM | ID: wpr-776678

الملخص

OBJECTIVE@#To investigate the physical development of Uygur and Han neonates in Urumqi, China.@*METHODS@#Live singleton neonates with a gestational age of 28-42 weeks who were born in the First Affiliated Hospital of Xinjiang Medical University and Maternal and Child Health Care Hospital from December 2014 to May 2017 were enrolled, and their body weight, body length, head circumference, and chest circumference at birth were measured. The cubic curve fitting method was used to plot the smooth curves of body weight, body length, head circumference, and chest circumference.@*RESULTS@#A total of 5 027 singleton neonates with a gestational age of 28-42 weeks were enrolled, with 2 625 boys and 2 402 girls. The average values of birth weight, body length, head circumference, and chest circumference, Quetelet index, and Ververck index of Uygur/Han boys and girls with a gestational age of 28-42 weeks were obtained, and related smoothed percentile curves were plotted. There were some differences between Uygur and Han neonates in the average values of some growth and development indices. The Quetelet index and the Ververck index of Uygur and Han neonates increased with the increase in gestational age, and the Uygur neonates had a higher Ververck index than the Han neonates.@*CONCLUSIONS@#There are differences in the levels of some growth and development indices and Ververck index between the Uygur and Han neonates in Urumqi. The average values of body weight, body length, chest circumference, and head circumference at birth, Quetelet index, and Ververck index of Uygur and Han neonates with a gestational age of 28-42 weeks and their smoothed percentile curves can provide a reference for the assessment of neonatal growth and development in Urumqi.


الموضوعات
Female , Humans , Infant, Newborn , Male , Birth Weight , Body Height , China , Cross-Sectional Studies , Gestational Age
7.
Journal of Medical Biomechanics ; (6): E092-E097, 2017.
مقالة ي صينى | WPRIM | ID: wpr-803817

الملخص

The function of health care and rehabilitation in Tai Chi has been recognized by the world. Studies on the mechanism of health care in Tai Chi have been conducted by domestic and international experts using the methods of sports biomechanics, most of which focus on human lower extremity. Twenty research literatures (15 articles in English and 5 articles in Chinese) during the year 2007-2015 about biomechanics of the lower extremity in Tai Chi were searched. According to the research purpose and evaluation index, this paper mainly reviewed from 3 aspects: the kinematic & kinetic characteristics of Tai Chi and its influence on the lower extremity, the effect of Tai Chi on muscle activity of the lower extremity, and the impact of Tai Chi movement on interaction between biomechanical parameters of the lower extremity and other system parameters. The prospects and limitations in biomechanical studies on the lower extremity in Tai Chi were also summarized.

8.
Journal of Medical Biomechanics ; (6): E506-E512, 2017.
مقالة ي صينى | WPRIM | ID: wpr-803837

الملخص

Objective To investigate the effect of different calcification patterns on the outcome of transcatheter aortic valve implantation (TAVI) by the finite element method. Methods Three calcified human aortic root models (coaptation line calcification model, attachment line calcification model and circular calcification model) were developed according to the location of calcified plaques on the aortic valve leaflets. The processes of self-expanding transcatheter aortic valve implanted into the 3 calcified models were simulated by ABAQUS software. The effects of different calcification patterns on the aortic root stresses, valve frame distortions and paravalvular gaps were analyzed. Results Circular calcification model had the largest maximum principal stress on calcified plaques (18.42 MPa), which might result in a higher risk of stroke after implantation; the circular calcification model also had the greatest distortion of the valve frame, which might lead to worse prosthetic durability; the paravalvular gaps area of the attachment line calcification model was 37.2 mm2, which was more than twice that of the other 2 models, causing more serious paravalvular regurgitation. Conclusions Different aortic valve calcification patterns are related to aortic root stresses, valve frame distortions and paravalvular gaps after TAVI, which will have an impact on postoperative complications and prothesis durability. The research findings provide references for the prediction of clinical outcome after TAVI.

9.
Journal of Medical Biomechanics ; (6): 506-512, 2017.
مقالة ي صينى | WPRIM | ID: wpr-701045

الملخص

Objective To investigate the effect of different calcification patterns on the outcome of transcatheter aortic valve implantation (TAVI) by the finite element method.Methods Three calcified human aortic root models (coaptation line calcification model,attachment line calcification model and circular calcification model) were developed according to the location of calcified plaques on the aortic valve leaflets.The processes of self-expanding transcatheter aortic valve implanted into the 3 calcified models were simulated by ABAQUS software.The effects of different calcification patterns on the aortic root stresses,valve frame distortions and paravalvular gaps were analyzed.Results Circular calcification model had the largest maximum principal stress on calcified plaques (18.42 MPa),which might result in a higher risk of stroke after implantation;the circular calcification model also had the greatest distortion of the valve frame,which might lead to worse prosthetic durability;the paravalvular gaps area of the attachment line calcification model was 37.2 mm2,which was more than twice that of the other 2 models,causing more serious paravalvular regurgitation.Cenclusiens Different aortic valve calcification patterns are related to aortic root stresses,valve frame distortions and paravalvular gaps after TAVI,which will have an impact on postoperative complications and prothesis durability.The research findings provide references for the prediction of clinical outcome after TAVI.

10.
مقالة ي صينى | WPRIM | ID: wpr-735841

الملخص

The function of health care and rehabilitation in Tai Chi has been recognized by the world.Studies on the mechanism of health care in Tai Chi have been conducted by domestic and international experts using the methods of sports biomechanics,most of which focus on human lower extremity.Twenty research literatures (15articles in English and 5 articles in Chinese) during the year 2007-2015 about biomechanics of the lower extremity in Tai Chi were searched.According to the research purpose and evaluation index,this paper mainly reviewed from 3 aspects:the kinematic & kinetic characteristics of Tai Chi and its influence on the lower extremity,the effect of Tai Chi on muscle activity of the lower extremity,and the impact of Tai Chi movement on interaction between biomechanical parameters of the lower extremity and other system parameters.The prospects and limitations in biomechanical studies on the lower extremity in Tai Chi were also summarized.

11.
Journal of Medical Biomechanics ; (6): 220-226, 2017.
مقالة ي صينى | WPRIM | ID: wpr-735860

الملخص

Objective To investigate the biomechanical effects of interbody cage height on cervical spine during anterior cervical discectomy and fusion (ACDF) surgery,so as to provide references for selection of interbody cage.Metheds The finite element model of normal cervical spine (C2-7) was built and validated,and the cages with different height (5,6,7,8 mm) were implanted into C5-6 disc (cage 5,6,7,8 model).All the models were loaded with pure moment of 1.5 N · m to produce flexion,extension,lateral bending and axial rotation motions on cervical spine,and the effects of cage height on range of motion (ROM),facet joint stress,intervertebral pressure in cervical spine were investigated.Results The intervertebral angle at the fusion segment increased by 0.68° with per 1 mm-increase in height.The ROM in C5-6 after cage implantation was smaller than 0.44°.The influence of cage height on ROM in C4-5 was greater than that in C6-7,and the changes of ROM in non-fusion segments were smaller than 7.3%.The cage height variation had a smaller impact on the facet joint stress and intervertebral pressure.The stresses in the capsular ligament,cage and screw-plate system increased gradually with the increase of cage height,and the stresses in cage 6,7,8 models were much higher than those in cage 5 model.Conclusions For patients who need implanting fusion cage,the cage height should be 0-1 mm greater than the original intervertebral space height.

12.
مقالة ي صينى | WPRIM | ID: wpr-737309

الملخص

The function of health care and rehabilitation in Tai Chi has been recognized by the world.Studies on the mechanism of health care in Tai Chi have been conducted by domestic and international experts using the methods of sports biomechanics,most of which focus on human lower extremity.Twenty research literatures (15articles in English and 5 articles in Chinese) during the year 2007-2015 about biomechanics of the lower extremity in Tai Chi were searched.According to the research purpose and evaluation index,this paper mainly reviewed from 3 aspects:the kinematic & kinetic characteristics of Tai Chi and its influence on the lower extremity,the effect of Tai Chi on muscle activity of the lower extremity,and the impact of Tai Chi movement on interaction between biomechanical parameters of the lower extremity and other system parameters.The prospects and limitations in biomechanical studies on the lower extremity in Tai Chi were also summarized.

13.
Journal of Medical Biomechanics ; (6): 220-226, 2017.
مقالة ي صينى | WPRIM | ID: wpr-737328

الملخص

Objective To investigate the biomechanical effects of interbody cage height on cervical spine during anterior cervical discectomy and fusion (ACDF) surgery,so as to provide references for selection of interbody cage.Metheds The finite element model of normal cervical spine (C2-7) was built and validated,and the cages with different height (5,6,7,8 mm) were implanted into C5-6 disc (cage 5,6,7,8 model).All the models were loaded with pure moment of 1.5 N · m to produce flexion,extension,lateral bending and axial rotation motions on cervical spine,and the effects of cage height on range of motion (ROM),facet joint stress,intervertebral pressure in cervical spine were investigated.Results The intervertebral angle at the fusion segment increased by 0.68° with per 1 mm-increase in height.The ROM in C5-6 after cage implantation was smaller than 0.44°.The influence of cage height on ROM in C4-5 was greater than that in C6-7,and the changes of ROM in non-fusion segments were smaller than 7.3%.The cage height variation had a smaller impact on the facet joint stress and intervertebral pressure.The stresses in the capsular ligament,cage and screw-plate system increased gradually with the increase of cage height,and the stresses in cage 6,7,8 models were much higher than those in cage 5 model.Conclusions For patients who need implanting fusion cage,the cage height should be 0-1 mm greater than the original intervertebral space height.

14.
Zhongguo dangdai erke zazhi ; Zhongguo dangdai erke zazhi;(12): 224-228, 2016.
مقالة ي صينى | WPRIM | ID: wpr-279867

الملخص

<p><b>OBJECTIVE</b>To investigate the risk factors for hearing impairment induced by cytomegalovirus (CMV) infection in children.</p><p><b>METHODS</b>One hundred and fifty-eight children diagnosed with CMV infection were enrolled as subjects. Based on the results of the brainstem auditory evoked potential (BAEP) test, patients were classified into normal hearing group (n=117; BAEP≤35) and abnormal hearing group (n=41; BAEP>35). A retrospective analysis was performed on the general information, routine blood indices, liver function, copy number of CMV-DNA in urine and breast milk. The receiver operating characteristic (ROC) curve was used to predict the copy number of CMV-DNA resulting in abnormal BAEP. The Spearman rank correlation analysis was used to test the correlations of the copy number of CMV-DNA in urine with the degree of hearing impairment and platelet count.</p><p><b>RESULTS</b>The incidence rates of platelet abnormality and abnormal liver function and the copy number of CMV-DNA in urine were significantly higher in the abnormal hearing group than in the normal hearing group (P<0.01). According to the ROC curve, the copy number of CMV-DNA in urine had a sensitivity of 46.3% and a specificity of 93.2% in predicting hearing impairment when it reached 1.415×10(6) per mL. The results of correlation analysis showed that the degree of hearing impairment was positively correlated with the copy number of CMV-DNA (r=0.382, P<0.01); the platelet count was negatively correlated with the copy number of CMV-DNA in urine (r=-0.233, P=0.003).</p><p><b>CONCLUSIONS</b>An increased copy number of CMV-DNA in urine might be a risk factor for hearing impairment induced by CMV infection. Children are likely to have hearing impairment when the copy number of CMV-DNA reaches 1.415×10(6) per mL. The monitoring of hearing should be strengthened in CMV-infected children with a decreased platelet count.</p>


الموضوعات
Female , Humans , Infant , Infant, Newborn , Male , Cytomegalovirus Infections , DNA, Viral , Urine , Evoked Potentials, Auditory, Brain Stem , Hearing Loss , Platelet Count , ROC Curve , Retrospective Studies , Risk Factors
15.
Journal of Medical Biomechanics ; (6): E135-E141, 2016.
مقالة ي صينى | WPRIM | ID: wpr-804018

الملخص

Objective To investigate the effects of element size and type, material property distributions of vertebral cancellous bone and simulation methods of cortical bone structure on the finite element (FE) results during the finite element modeling of lumbar vertebral body. Methods Based on QCT images of lumbar spine, 22 FE models of L2 without posterior structure were built by 6 element sizes (0.5, 1.0, 1.5, 2.0, 2.5, 3.0 mm), 2 heterogeneous material distribution methods of cancellous bone (300, 150) and 2 cortical bone modeling methods. The maximum displacement, strain energy, average stress and axial stiffness of these models were obtained to analyze and verify the results. Results When the element size was 0.5 mm, the axial stiffness of models with 10, 150 and 300 kinds of heterogeneous materials showed obvious differences; for the vertebral cancellous bone with 150 kinds of materials, the variation of average stress was not distinct under different element sizes; the average stress of the model using the outermost hexahedral elements to simulate the cortical bone structure was larger than that appending the skin to the outmost of the model. Conclusions It is more reasonable and effective to build the FE model of lumbar vertebral body with the method by 0.5 mm element size, 8-noded hexahedral elements, 150 kinds of heterogeneous materials, and using the outermost hexahedral elements to simulate the cortical bone structure. The research findings will lay a foundation for building subject-specific FE models of lumbar vertebral body on a large scale in future.

16.
Journal of Medical Biomechanics ; (6): E008-E013, 2015.
مقالة ي صينى | WPRIM | ID: wpr-804404

الملخص

Objective To investigate the effects of unevenly-distributed backpack loads on human physiological parameters as compared to the traditional centrally-placed load at the backpack bottom. Methods For the unevenly-distributed load mode, the backpack was divided into four spaces including top right, top left, bottom right and bottom left. The loads were divided into two parts proportionally (1/2∶1/2, 1/4∶3/4 and 3/4∶1/4) and placed at the bottom left and top right of the backpack, respectively. The remaining two spaces were filled with the plastic foam. Ten healthy volunteers performed 30-min walking trials on the treadmill at the speed of 1.1 m/s with the backpack load equal to 10% body weight (BW). The changes of subjects’ body posture, muscle fatigue, heart rate, blood pressure before and after the trial, as well as the electromyography (EMG) changes at 0, 5, 10, 15 min after the trial were measured by the Bortec AMT-8 and the NDI Optotrak Certus. Results The muscle fatigue of right upper trapezius and forward-leaning angle increased as the loads at top right of the backpack increased. However, the muscle fatigue in the new mode of backpack load distribution showed no significant differences as compared to the traditional mode under the same backpack loads. The new mode with the load ratio of 3/4∶1/4 had no significant effects on posture. The new mode with the load ratio of 1/2∶1/2 could contribute to the decrease of heart rate and blood pressure as compared to the traditional mode. Conclusions Adopting a new and more reasonable load distribution mode can guarantee the body posture unaffected by the backpack loads, and decrease heart rate and blood pressure. Therefore, the cross and evenly distributed load mode is recommended for the backpack design.

17.
Journal of Medical Biomechanics ; (6): E327-E333, 2014.
مقالة ي صينى | WPRIM | ID: wpr-804314

الملخص

Objective To study the biomechanical effects of 3 different retention methods (clasp, attachment or zygomatic implants) on repairing unilateral maxillary defects by using 3D finite element analysis method. Methods The maxillary unilateral defect model was reconstructed by the medical image processing software Mimics. The prosthesis was generated by mirroring technology. After processing, the finite element model of maxillary model by the three different retention methods was established to simulate stress distributions of maxilla during occlusion. Results Compared with the other methods, by using zygomatic implant retention method, stresses on affected and unaffected palate were the largest as 7.399 and 4.864 MPa, respectively, while those on affected and unaffected maxilla were the smallest as 10.46 and 10.86 MPa, respectively. Stress on zygomatic implant itself was 15.25 MPa, which was also the smallest. Conclusions Different retention methods had an obvious impact on unilateral maxillary defect restoration. The clasp and attachment retention methods could share the stress on palate by carrying bracket. The zygomatic implant retention method could also share the stress on maxilla by passing the stress to the zygoma.

18.
Journal of Medical Biomechanics ; (6): E399-E404, 2014.
مقالة ي صينى | WPRIM | ID: wpr-804342

الملخص

Objective To study biomechanical effects of the lumbar spine under different traction conditions by using three-dimensional (3D) finite element method. Methods The CT images of lumbar segment L1-5 were input to the Mimics 10.01 for developing 3D geometrical model of L1-5. Then the mesh model of L1-5 was obtained using Geomagic Studio 12.0 and Hypermesh 11.0. The finite element simulation of the lumbar spine under different traction conditions was made by using Abaqus. Results Head-down titling angle was related to the nucleus pulposus stress. When the head-down tilting angle was smaller than 10°, the nucleus pulposus stress regularly changed with the swing cycle; while the head-down tilting angle exceeded 10°, the stress was decreased. In the swing mode, the annulus inner ring stress was increased to promote intervertebral retraction. Conclusions The traction mode helps to relieve the lumbar pain with the swing helping to coordinate the traction effect in each direction, which can better sort out and relieve the rear facet joint disorders. In addition, patients should be careful to select the appropriate traction force in the treatment to achieve good therapeutic effect.

19.
Journal of Medical Biomechanics ; (6): E072-E077, 2014.
مقالة ي صينى | WPRIM | ID: wpr-804367

الملخص

Objective To study the biomechanical effect from different prosthetic materials used on unilateral maxillary defect repair by three dimensional finite element (FE) analysis method. Methods The maxillary unilateral defect model was reconstructed by medical image processing software MIMICS. The prosthesis was generated by mirroring technology. After processing, the FE unilateral maxillary defect model and healthy maxillary model were established to simulate stress distributions on the maxilla during occlusion. Results The maximum stress on maxilla using different repair materials was always found concentrated on the edge of maxilla connected with zygoma (the positions attaching zygolabialis and levator anguli oris). The minimum stress of from the maxilla edge on the repair side was 8.471 MPa by using tricalcium phosphate (TCP) composite. The maximum stress from the maxilla edge on the repair side was 17.55 MPa by using hydroxyapatite (HA) material. Conclusions Different repair materials had no significant effect on natural side of the maxilla after restoration, while a greater impact of force status on the repair side was found. The elastic modulus of different repair materials can be used as a basis for maxilla restoration in clinic.

20.
Journal of Medical Biomechanics ; (6): E154-E160, 2014.
مقالة ي صينى | WPRIM | ID: wpr-804397

الملخص

Objective To study dynamic characteristics of human lumbar spine using three-dimensional finite element method. Methods Finite element model of lumbar spine (L1~5) was developed and validated based on CT images, and the modal analysis was also conducted. Results A total of top 30-order modal parameters were extracted to obtain dynamic characteristics of the lumbar spine under free boundary conditions. Resonance frequencies of the model were concentrately distributed, but the amplitude of each order varied greatly. Amplitude near L5 segment was much larger, indicating L5 was easily to be injured. This lumbar modal analysis could provide a basis for its further dynamic analysis. Parameters such as natural frequency, modal shape and vibration amplitude of the lumbar spine would be helpful for both lumbar dynamic analysis and optimal design of man-machine interface mechanical equipment.

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