The three-dimensional finite element method is used to solve the problem of the quarter-elliptical comer crack of the bolt-hole in mechanical joints being subjected to remote tension. The square-root stress singularit...The three-dimensional finite element method is used to solve the problem of the quarter-elliptical comer crack of the bolt-hole in mechanical joints being subjected to remote tension. The square-root stress singularity around the corner crack front is simulated using the collapsed 20-node quarter point singular elements. The contact interaction between the bolt and the hole boundary is considered in the finite element analysis. The stress intensity factors （SIFs） along the crack front are evaluated by using the displacement correlation technique. The effects of the amount of clearance between the hole and the bolt on the SIFs are investigated. The numerical results indicate that the SIF for mode I decrease with the decreases in clearance, and in the cases of clearance being present, the corner crack is in a mix-mode, even if mode I loading is dominant.展开更多
Despite significant improvements over the past several decades in diagnosis,treatment and prevention of periprosthetic joint infection(PJI),it still remains a major challenge following total joint arthroplasty.Given t...Despite significant improvements over the past several decades in diagnosis,treatment and prevention of periprosthetic joint infection(PJI),it still remains a major challenge following total joint arthroplasty.Given the devastating nature and accelerated incidence of PJI,prevention is the most important strategy to deal with this challenging problem and should start from identifying risk factors.Understanding and well-organized optimization of these risk factors in individuals before elective arthroplasty are essential to the ultimate success in reducing the incidence of PJI.Even though some risk factors such as demographic characteristics are seldom changeable,they allow more accurate expectation regarding individual risks of PJI and thus,make proper counseling for shared preoperative decision-making possible.Others that increase the risk of PJI,but are potentially modifiable should be optimized prior to elective arthroplasty.Although remarkable advances have been achieved in past decades,many questions regarding standardized practice to prevent this catastrophic complication remain unanswered.The current study provide a comprehensive knowledge regarding risk factors based on general principles to control surgical siteinfection by the review of current literature and also share own practice at our institution to provide practical and better understandings.展开更多
Finding crucial vertices is a key problem for improving the reliability and ensuring the effective operation of networks,solved by approaches based on multiple attribute decision that suffer from ignoring the correlat...Finding crucial vertices is a key problem for improving the reliability and ensuring the effective operation of networks,solved by approaches based on multiple attribute decision that suffer from ignoring the correlation among each attribute or the heterogeneity between attribute and structure. To overcome these problems, a novel vertex centrality approach, called VCJG, is proposed based on joint nonnegative matrix factorization and graph embedding. The potential attributes with linearly independent and the structure information are captured automatically in light of nonnegative matrix factorization for factorizing the weighted adjacent matrix and the structure matrix, which is generated by graph embedding. And the smoothness strategy is applied to eliminate the heterogeneity between attributes and structure by joint nonnegative matrix factorization. Then VCJG integrates the above steps to formulate an overall objective function, and obtain the ultimately potential attributes fused the structure information of network through optimizing the objective function. Finally, the attributes are combined with neighborhood rules to evaluate vertex's importance. Through comparative analyses with experiments on nine real-world networks, we demonstrate that the proposed approach outperforms nine state-of-the-art algorithms for identification of vital vertices with respect to correlation, monotonicity and accuracy of top-10 vertices ranking.展开更多
Objective To explore the relative factors affecting the functional restoration of knee joint after the fracture of patella, and to anticipate the effect of middle-term and short-time rehabilitation therapy. Method 23 ...Objective To explore the relative factors affecting the functional restoration of knee joint after the fracture of patella, and to anticipate the effect of middle-term and short-time rehabilitation therapy. Method 23 patients with limited flexion function of knee joint after the fracture of patella, accepted the routine rehabilitation treatment in out -patient service, and some of the patients adopted local heat therapy at the same time. The 13 factors have been selected for regression analysis step by step under the help of SPSS statistical software. Result The flexible degree of the knee joint before rehabilitation (X1), the non-smooth posterior edge of patella (X2), and the immobilization time of the joint (X3) are relative factors for the flexible degree of knee joint 1 month after rehabilitation (Y1) and the flexible degree of knee joint 3 months after rehabilitation (Y2), and Y1 can also be affected by whether surgery therapy or not (X4), (partial regression coefficient P< 0.05). The differences between theoretical mean and practical mean of Y1 and Y2 are 5.6% and 4.2% respectively in the 23 cases. Conclusion The flexible degree of the knee joint before rehabilitation, whether the posterior edge of patella is smooth or not, and the immobilization time of the joint are relative factors affecting the middle-term and short-term flexible function of knee joint after the fracture of patella, and short-term restoration can also be affected by whether surgery therapy or not. The effects of middle-term and short-term rehabilitation can be predicted by regression equation primarily.展开更多
AIM To evaluate the changes in the 8^(th) edition American Joint Committee on Cancer(AJCC) for defining stage?ⅠB and?ⅡA pancreatic cancer and identify their prognostic factors.METHODS Pancreatic cancer patients were...AIM To evaluate the changes in the 8^(th) edition American Joint Committee on Cancer(AJCC) for defining stage?ⅠB and?ⅡA pancreatic cancer and identify their prognostic factors.METHODS Pancreatic cancer patients were selected from the Surveillance Epidemiology and End Results database(1973-2013). The enrolled patients were divided into?ⅠB and?ⅡA groups based on tumor size according to the 8^(th) edition AJCC criteria. Clinical characteristics, including age, gender, race, tumor size, primary site, and grade were summarized. Univariate and multivariate analyses were performed to explore the prognostic factors of the?ⅠB and?ⅡA stages of pancreatic cancer under new criteria.RESULTS A total of 1349 pancreatic cancer patients were included. More patients had stage?ⅠB rather than stage?ⅡA. Stage?ⅠB tumors(54.85%) were mainly located in the head of the pancreas, while stage?ⅡA tumors were more often located in the tail and head of the pancreas(35.21% and 31.75%, respectively). The survival time of stage?ⅠB and?ⅡA patients had no significant difference. Univariate and multivariate analyses indicated that the prognostic factors of survival for stage?ⅠB and?ⅡA patients were different. for stage?ⅠB patients, age and primary site were the independent prognostic factors; for stage?ⅡA patients, age and grade were the independent prognostic factors. The risk of death was lower among patients aged ≤ 65 years than those aged > 65 years.CONCLUSION The prognostic factors for stage?ⅠB and?ⅡA patients are different, but age is the independent prognostic factor for all patients. The survival time of stage?ⅠB and?ⅡA patients has no significant difference.展开更多
In order to improve the bending load-carrying capacity （BLCC） of undermatched butt joint under three-point bending load, the influence of joint geometric parameters on stress concentration factors （SCF） at the wel...In order to improve the bending load-carrying capacity （BLCC） of undermatched butt joint under three-point bending load, the influence of joint geometric parameters on stress concentration factors （SCF） at the weld bottom center and the weld toe of uudermatched butt joint with single V-groove are studied respectively based on the finite element method in this paper. Results show that the reinforcement height and the cover pass width play decisive role in the BLCC for undermatched butt joint. BLCC of undermatched butt joint can be improved by choosing the appropriate joint geometric parameters.展开更多
Taking cruciform welded joints under different corrosion degrees, together with 45° inclined angle and full penetration load-carrying fillet, as the research object, the stress intensity factor of a quarter-circu...Taking cruciform welded joints under different corrosion degrees, together with 45° inclined angle and full penetration load-carrying fillet, as the research object, the stress intensity factor of a quarter-circular comer crack of welded joints is calculated based on FRANC3D with ABAQUS. Effects of different corrosion pit sizes, crack aspect ratios, and crack depths on stress intensity factor are analyzed. The results show that pit depth plays a major role in stress intensity factor, while the effect of pit radius is relatively small. The cracking modes of the surface and the deepest point are mode I, and mixed modes I and II, respectively. Effects of pit depths, crack aspect ratios, and crack depths on the stress intensity factor at the surface point are greater than at the deepest point.展开更多
In this research, the influence of such joint geometric parameters as weld width and reinforcement on shape ~actor of butt joint with center crack subjected to static loading was investigated by finite element analyse...In this research, the influence of such joint geometric parameters as weld width and reinforcement on shape ~actor of butt joint with center crack subjected to static loading was investigated by finite element analyses method. According to the analytical resuhs, a well fracture resistant joint shape of butt joint with center crack has been approved.展开更多
Objective: The aim of the study was to evaluate the effect of platelet rich growth factors (PRGFs) in treatment of temporomandibular joint disc displacement. Materials and Methods: The study subjects included 8 female...Objective: The aim of the study was to evaluate the effect of platelet rich growth factors (PRGFs) in treatment of temporomandibular joint disc displacement. Materials and Methods: The study subjects included 8 females having bilateral anterior disc displacement with reduction and 1 female having bilateral anterior disc displacement without reduction with the age range between 20 - 35 years. The process of obtaining PRGFs was carried out following the Anitua Technique. Results: Clinical parameters of Interincisal distance, Lateral excursion of mandible using digital caliper in millimeters and Visual Analogue Scale (VAS 0/10) for pain intensity score were used. All of these parameters were running through the intervals of two, four, and eight weeks till the end of the follow-up period at twenty-six weeks (six months). The participated patients showed the clinical improvement in the different clinical statuses such as interincisal distance;lateral excursion of mandible and Pain Score. Conclusion: the study reported early efficacy of PRGFs after the arthrocentesis of the joint in treatment of TMJ disc displacement, and according to our results, the injection of PRGFs could be a possible alternative treatment for patients who did not respond to standard treatment.展开更多
The irregularity of jointed network poses a challenge to the determination of field mechanical param-eters of columnar jointed rock mass(CJRM),and a reasonable prediction of deformation and strength characteristics of...The irregularity of jointed network poses a challenge to the determination of field mechanical param-eters of columnar jointed rock mass(CJRM),and a reasonable prediction of deformation and strength characteristics of CJRM is important for engineering construction.The Voronoi diagram and three-dimensional printing technology were used to make an irregular columnar jointed mold,and the irregular CJRM(ICJRM)specimens with different dip directions and dip angles were prepared.Uniaxial compression tests were performed,and the anisotropic strength and deformation characteristics of ICJRM were described.The failure modes and mechanisms were revealed in accordance with the final appearances of the ICJRM specimens.Based on the model test results,the empirical correlations for determining the field deformation and strength parameters of CJRM were derived using the dip angle and modified joint factor.The proposed empirical equations were used in the Baihetan Project,and the calculated mechanical parameters were compared with the field test results and those obtained from the tunneling quality index method.Results showed that the deformation parameters determined by the two proposed methods are all consistent with the field test results,and these two methods can also estimate the strength parameters effectively.展开更多
基金National Natural Science Foundation of China (10272036)
文摘The three-dimensional finite element method is used to solve the problem of the quarter-elliptical comer crack of the bolt-hole in mechanical joints being subjected to remote tension. The square-root stress singularity around the corner crack front is simulated using the collapsed 20-node quarter point singular elements. The contact interaction between the bolt and the hole boundary is considered in the finite element analysis. The stress intensity factors （SIFs） along the crack front are evaluated by using the displacement correlation technique. The effects of the amount of clearance between the hole and the bolt on the SIFs are investigated. The numerical results indicate that the SIF for mode I decrease with the decreases in clearance, and in the cases of clearance being present, the corner crack is in a mix-mode, even if mode I loading is dominant.
基金Supported by The grant of Research Institute of Medical Science,Catholic University of Daegu(2011)
文摘Despite significant improvements over the past several decades in diagnosis,treatment and prevention of periprosthetic joint infection(PJI),it still remains a major challenge following total joint arthroplasty.Given the devastating nature and accelerated incidence of PJI,prevention is the most important strategy to deal with this challenging problem and should start from identifying risk factors.Understanding and well-organized optimization of these risk factors in individuals before elective arthroplasty are essential to the ultimate success in reducing the incidence of PJI.Even though some risk factors such as demographic characteristics are seldom changeable,they allow more accurate expectation regarding individual risks of PJI and thus,make proper counseling for shared preoperative decision-making possible.Others that increase the risk of PJI,but are potentially modifiable should be optimized prior to elective arthroplasty.Although remarkable advances have been achieved in past decades,many questions regarding standardized practice to prevent this catastrophic complication remain unanswered.The current study provide a comprehensive knowledge regarding risk factors based on general principles to control surgical siteinfection by the review of current literature and also share own practice at our institution to provide practical and better understandings.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.62162040 and 11861045)。
文摘Finding crucial vertices is a key problem for improving the reliability and ensuring the effective operation of networks,solved by approaches based on multiple attribute decision that suffer from ignoring the correlation among each attribute or the heterogeneity between attribute and structure. To overcome these problems, a novel vertex centrality approach, called VCJG, is proposed based on joint nonnegative matrix factorization and graph embedding. The potential attributes with linearly independent and the structure information are captured automatically in light of nonnegative matrix factorization for factorizing the weighted adjacent matrix and the structure matrix, which is generated by graph embedding. And the smoothness strategy is applied to eliminate the heterogeneity between attributes and structure by joint nonnegative matrix factorization. Then VCJG integrates the above steps to formulate an overall objective function, and obtain the ultimately potential attributes fused the structure information of network through optimizing the objective function. Finally, the attributes are combined with neighborhood rules to evaluate vertex's importance. Through comparative analyses with experiments on nine real-world networks, we demonstrate that the proposed approach outperforms nine state-of-the-art algorithms for identification of vital vertices with respect to correlation, monotonicity and accuracy of top-10 vertices ranking.
文摘Objective To explore the relative factors affecting the functional restoration of knee joint after the fracture of patella, and to anticipate the effect of middle-term and short-time rehabilitation therapy. Method 23 patients with limited flexion function of knee joint after the fracture of patella, accepted the routine rehabilitation treatment in out -patient service, and some of the patients adopted local heat therapy at the same time. The 13 factors have been selected for regression analysis step by step under the help of SPSS statistical software. Result The flexible degree of the knee joint before rehabilitation (X1), the non-smooth posterior edge of patella (X2), and the immobilization time of the joint (X3) are relative factors for the flexible degree of knee joint 1 month after rehabilitation (Y1) and the flexible degree of knee joint 3 months after rehabilitation (Y2), and Y1 can also be affected by whether surgery therapy or not (X4), (partial regression coefficient P< 0.05). The differences between theoretical mean and practical mean of Y1 and Y2 are 5.6% and 4.2% respectively in the 23 cases. Conclusion The flexible degree of the knee joint before rehabilitation, whether the posterior edge of patella is smooth or not, and the immobilization time of the joint are relative factors affecting the middle-term and short-term flexible function of knee joint after the fracture of patella, and short-term restoration can also be affected by whether surgery therapy or not. The effects of middle-term and short-term rehabilitation can be predicted by regression equation primarily.
文摘AIM To evaluate the changes in the 8^(th) edition American Joint Committee on Cancer(AJCC) for defining stage?ⅠB and?ⅡA pancreatic cancer and identify their prognostic factors.METHODS Pancreatic cancer patients were selected from the Surveillance Epidemiology and End Results database(1973-2013). The enrolled patients were divided into?ⅠB and?ⅡA groups based on tumor size according to the 8^(th) edition AJCC criteria. Clinical characteristics, including age, gender, race, tumor size, primary site, and grade were summarized. Univariate and multivariate analyses were performed to explore the prognostic factors of the?ⅠB and?ⅡA stages of pancreatic cancer under new criteria.RESULTS A total of 1349 pancreatic cancer patients were included. More patients had stage?ⅠB rather than stage?ⅡA. Stage?ⅠB tumors(54.85%) were mainly located in the head of the pancreas, while stage?ⅡA tumors were more often located in the tail and head of the pancreas(35.21% and 31.75%, respectively). The survival time of stage?ⅠB and?ⅡA patients had no significant difference. Univariate and multivariate analyses indicated that the prognostic factors of survival for stage?ⅠB and?ⅡA patients were different. for stage?ⅠB patients, age and primary site were the independent prognostic factors; for stage?ⅡA patients, age and grade were the independent prognostic factors. The risk of death was lower among patients aged ≤ 65 years than those aged > 65 years.CONCLUSION The prognostic factors for stage?ⅠB and?ⅡA patients are different, but age is the independent prognostic factor for all patients. The survival time of stage?ⅠB and?ⅡA patients has no significant difference.
基金The authors are grateful to be financially supported by Projects of Natural Science Foundation of Heilongjiang Province （No. E201458） , State Key Lab of Advanced Welding and Joining, Har- bin Institute of Technology （AWJ-M13-14） and Hei longjiang Prov- ince Department of Education （12541679）.
文摘In order to improve the bending load-carrying capacity （BLCC） of undermatched butt joint under three-point bending load, the influence of joint geometric parameters on stress concentration factors （SCF） at the weld bottom center and the weld toe of uudermatched butt joint with single V-groove are studied respectively based on the finite element method in this paper. Results show that the reinforcement height and the cover pass width play decisive role in the BLCC for undermatched butt joint. BLCC of undermatched butt joint can be improved by choosing the appropriate joint geometric parameters.
基金supported by the National Natural Science Foundation of China(51378430 and 51378431)
文摘Taking cruciform welded joints under different corrosion degrees, together with 45° inclined angle and full penetration load-carrying fillet, as the research object, the stress intensity factor of a quarter-circular comer crack of welded joints is calculated based on FRANC3D with ABAQUS. Effects of different corrosion pit sizes, crack aspect ratios, and crack depths on stress intensity factor are analyzed. The results show that pit depth plays a major role in stress intensity factor, while the effect of pit radius is relatively small. The cracking modes of the surface and the deepest point are mode I, and mixed modes I and II, respectively. Effects of pit depths, crack aspect ratios, and crack depths on the stress intensity factor at the surface point are greater than at the deepest point.
文摘In this research, the influence of such joint geometric parameters as weld width and reinforcement on shape ~actor of butt joint with center crack subjected to static loading was investigated by finite element analyses method. According to the analytical resuhs, a well fracture resistant joint shape of butt joint with center crack has been approved.
文摘Objective: The aim of the study was to evaluate the effect of platelet rich growth factors (PRGFs) in treatment of temporomandibular joint disc displacement. Materials and Methods: The study subjects included 8 females having bilateral anterior disc displacement with reduction and 1 female having bilateral anterior disc displacement without reduction with the age range between 20 - 35 years. The process of obtaining PRGFs was carried out following the Anitua Technique. Results: Clinical parameters of Interincisal distance, Lateral excursion of mandible using digital caliper in millimeters and Visual Analogue Scale (VAS 0/10) for pain intensity score were used. All of these parameters were running through the intervals of two, four, and eight weeks till the end of the follow-up period at twenty-six weeks (six months). The participated patients showed the clinical improvement in the different clinical statuses such as interincisal distance;lateral excursion of mandible and Pain Score. Conclusion: the study reported early efficacy of PRGFs after the arthrocentesis of the joint in treatment of TMJ disc displacement, and according to our results, the injection of PRGFs could be a possible alternative treatment for patients who did not respond to standard treatment.
基金This work was supported by the Fundamental Research Funds for the Central Universities,the Postgraduate Research&Practice Innovation Program of Jiangsu Province(Grant No.KYCX21_0487)the National Natural Science Foundation of China(Grant Nos.41831278,and 51579081).
文摘The irregularity of jointed network poses a challenge to the determination of field mechanical param-eters of columnar jointed rock mass(CJRM),and a reasonable prediction of deformation and strength characteristics of CJRM is important for engineering construction.The Voronoi diagram and three-dimensional printing technology were used to make an irregular columnar jointed mold,and the irregular CJRM(ICJRM)specimens with different dip directions and dip angles were prepared.Uniaxial compression tests were performed,and the anisotropic strength and deformation characteristics of ICJRM were described.The failure modes and mechanisms were revealed in accordance with the final appearances of the ICJRM specimens.Based on the model test results,the empirical correlations for determining the field deformation and strength parameters of CJRM were derived using the dip angle and modified joint factor.The proposed empirical equations were used in the Baihetan Project,and the calculated mechanical parameters were compared with the field test results and those obtained from the tunneling quality index method.Results showed that the deformation parameters determined by the two proposed methods are all consistent with the field test results,and these two methods can also estimate the strength parameters effectively.
