Biomimetic design employs the principles of nature to solve engineering problems. Such designs which are hoped to be quick, efficient, robust, and versatile, have taken advantage of optimization via natural selection....Biomimetic design employs the principles of nature to solve engineering problems. Such designs which are hoped to be quick, efficient, robust, and versatile, have taken advantage of optimization via natural selection. In the present research, an environment-friendly propulsion system mimicking undulating fins of stingray was built. A non-conventional method was considered to model the flexibility of the fins of stingray. A two-degree-of-freedom mechanism comprised of several linkages was designed and constructed to mimic the actual flexible fin, The driving linkages were used to form a mechanical fin consisting of several fin segments, which are able tO produce undulations, similar to those produced by the actual fins. Owing to the modularity of the design of the mechanical fin, various undulating patterns can be realized. Some qualitative observations, obtained by experiments, predicted that the thrusts produced by the mechanical fin are different among various undulating patterns. To fully understand this experimental phenomenon is very important for better performance and energy saving for our biorobotic underwater propulsion system. Here, four basic undulating patterns of the mechanical fin were performed using two-dimensional unsteady computational fluid dynamics （CFD） method. An unstructured, grid-based, unsteady Navier-Stokes solver with automatic adaptive re-meshing was used to compute the unsteady flow around the fin through twenty complete cycles. The pressure distribution on fin surface was computed and integrated to provide fin forces which were decomposed into rift and thrust. The pressure force and friction force were also computed throughout the swimming cycle. Finally, vortex contour maps of these four basic fin undulating patterns were displayed and compared.展开更多
The treatment and prognosis of malignant tumors are closely related to the time when the tumors are diagnosed;the earlier the diagnosis of the tumor,the better the prognosis.However,most tumors are not detected in the...The treatment and prognosis of malignant tumors are closely related to the time when the tumors are diagnosed;the earlier the diagnosis of the tumor,the better the prognosis.However,most tumors are not detected in the early stages of screening and diagnosis.It is of great clinical significance to study the correlation between multiple pathogeneses of tumors and explore simple,safe,specific,and sensitive molecular indicators for early screening,diagnosis,and prognosis.The Septin 9(SEPT9)gene has been found to be associated with a variety of human diseases,and it plays a role in the development of tumors.SEPT9 is a member of the conserved family of cytoskeletal GTPase,which consists of a P-loop-based GTP-binding domain flanked by a variable N-terminal region and a C-terminal region.SEPT9 is involved in many biological processes such as cytokinesis,polarization,vesicle trafficking,membrane reconstruction,deoxyribonucleic acid repair,cell migration,and apoptosis.Several studies have shown that SEPT9 may serve as a marker for early screening,diagnosis,and prognosis of some malignant tumors,and have the potential to become a new target for anti-cancer therapy.This article reviews the progress in research on the SEPT9 gene in early screening,diagnosis,and prognosis of tumors.展开更多
The detailed process and mechanism of colonic motility are still unclear, and colonic motility disorders are associated with numerous clinical diseases. Colonic manometry is considered to the most direct means of eval...The detailed process and mechanism of colonic motility are still unclear, and colonic motility disorders are associated with numerous clinical diseases. Colonic manometry is considered to the most direct means of evaluating colonic peristalsis. Colonic manometry has been studied for more than 30 years;however, the long duration of the examination, high risk of catheterization, huge amount of real-time data, strict catheter sterilization, and high cost of disposable equipment restrict its wide application in clinical practice. Recently, highresolution colonic manometry (HRCM) has rapidly developed into a major technique for obtaining more effective information involved in the physiology and/or pathophysiology of colonic contractile activity in colonic dysmotility patients. This review focuses on colonic motility, manometry, operation, and motor patterns, and the clinical application of HRCM. Furthermore, the limitations, future directions, and potential usefulness of HRCM in the evaluation of clinical treatment effects are also discussed.展开更多
Many fishes use undulatory fin to propel themselves in the underwater environment. These locomotor mechanisms have a popular interest to many researchers. In the present study, we perform a three-dimensional unsteady ...Many fishes use undulatory fin to propel themselves in the underwater environment. These locomotor mechanisms have a popular interest to many researchers. In the present study, we perform a three-dimensional unsteady computation of an undulatory mechanical fin that is driven by Shape Memory Alloy （SMA）. The objective of the computation is to investigate the fluid dynamics of force production associated with the undulatory mechanical fin. An unstructured, grid-based, unsteady Navier-Stokes solver with automatic adaptive remeshing is used to compute the unsteady flow around the fin through five complete cycles. The pressure distribution on fin surface is computed and integrated to provide fin forces which are decomposed into lift and thrust. The velocity field is also computed throughout the swimming cycle. Finally, a comparison is conducted to reveal the dynamics of force generation according to the kinematic parameters of the undulatory fin （amplitude, frequency and wavelength）.展开更多
BACKGROUND Neuroendocrine tumors(NETs)frequently occur in the gastrointestinal tract,lung,and pancreas,and the rectum and appendix are the sites with the highest incidence.Epidemiology statistics show that an estimate...BACKGROUND Neuroendocrine tumors(NETs)frequently occur in the gastrointestinal tract,lung,and pancreas,and the rectum and appendix are the sites with the highest incidence.Epidemiology statistics show that an estimated 8000 people every year in the United States are diagnosed with NETs occurring in the gastrointestinal tract,including the stomach,intestine,appendix,colon,and rectum.The pathological changes and clinical symptoms of NETs are not specific,and therefore they are frequently misdiagnosed.AIM To investigate the clinical symptoms,pathological characteristics,treatment,and prognosis of rectal neuroendocrine tumors(RNETs)by analyzing the clinical and pathological data of 132 RNET cases at our hospital.METHODS All RNETs were graded according to Ki-67 positivity and mitotic events.The tumors were staged as clinical stages I,II,III,and IV according to infiltrative depth and tumor size.COX proportional hazard model was used to assess the main risk factors for survival.RESULTS These 132 RNETs included 83 cases of G1,21 cases of G2,and 28 cases of G3(neuroendocrine carcinoma)disease.Immunohistochemical staining showed that 89.4%of RNETs were positive for synaptophysin and 39.4%positive for chromogranin A.There were 19,85,23,and 5 cases of clinical stages I,II,III,and IV,respectively.The median patient age was 52.96 years.The diameter of tumor,depth of invasion,and pathological grade were the main reference factors for the treatment of RNETs.The survival rates at 6,12,36,and 60 mo after operation were 98.5%,94.6%,90.2%,and 85.6%,respectively.Gender,tumor size,tumor grade,lymph node or distant organ metastasis,and radical resection were the main factors associated with prognosis of RNETs.Multivariate analysis showed that tumor size and grade were independent prognostic factors.CONCLUSION The clinical symptoms of RNETs are not specific,and they are easy to misdiagnose.Surgery is the main treatment method.The grade and stage of RNETs are the main indices to evaluate prognosis.展开更多
文摘Biomimetic design employs the principles of nature to solve engineering problems. Such designs which are hoped to be quick, efficient, robust, and versatile, have taken advantage of optimization via natural selection. In the present research, an environment-friendly propulsion system mimicking undulating fins of stingray was built. A non-conventional method was considered to model the flexibility of the fins of stingray. A two-degree-of-freedom mechanism comprised of several linkages was designed and constructed to mimic the actual flexible fin, The driving linkages were used to form a mechanical fin consisting of several fin segments, which are able tO produce undulations, similar to those produced by the actual fins. Owing to the modularity of the design of the mechanical fin, various undulating patterns can be realized. Some qualitative observations, obtained by experiments, predicted that the thrusts produced by the mechanical fin are different among various undulating patterns. To fully understand this experimental phenomenon is very important for better performance and energy saving for our biorobotic underwater propulsion system. Here, four basic undulating patterns of the mechanical fin were performed using two-dimensional unsteady computational fluid dynamics （CFD） method. An unstructured, grid-based, unsteady Navier-Stokes solver with automatic adaptive re-meshing was used to compute the unsteady flow around the fin through twenty complete cycles. The pressure distribution on fin surface was computed and integrated to provide fin forces which were decomposed into rift and thrust. The pressure force and friction force were also computed throughout the swimming cycle. Finally, vortex contour maps of these four basic fin undulating patterns were displayed and compared.
文摘The treatment and prognosis of malignant tumors are closely related to the time when the tumors are diagnosed;the earlier the diagnosis of the tumor,the better the prognosis.However,most tumors are not detected in the early stages of screening and diagnosis.It is of great clinical significance to study the correlation between multiple pathogeneses of tumors and explore simple,safe,specific,and sensitive molecular indicators for early screening,diagnosis,and prognosis.The Septin 9(SEPT9)gene has been found to be associated with a variety of human diseases,and it plays a role in the development of tumors.SEPT9 is a member of the conserved family of cytoskeletal GTPase,which consists of a P-loop-based GTP-binding domain flanked by a variable N-terminal region and a C-terminal region.SEPT9 is involved in many biological processes such as cytokinesis,polarization,vesicle trafficking,membrane reconstruction,deoxyribonucleic acid repair,cell migration,and apoptosis.Several studies have shown that SEPT9 may serve as a marker for early screening,diagnosis,and prognosis of some malignant tumors,and have the potential to become a new target for anti-cancer therapy.This article reviews the progress in research on the SEPT9 gene in early screening,diagnosis,and prognosis of tumors.
文摘The detailed process and mechanism of colonic motility are still unclear, and colonic motility disorders are associated with numerous clinical diseases. Colonic manometry is considered to the most direct means of evaluating colonic peristalsis. Colonic manometry has been studied for more than 30 years;however, the long duration of the examination, high risk of catheterization, huge amount of real-time data, strict catheter sterilization, and high cost of disposable equipment restrict its wide application in clinical practice. Recently, highresolution colonic manometry (HRCM) has rapidly developed into a major technique for obtaining more effective information involved in the physiology and/or pathophysiology of colonic contractile activity in colonic dysmotility patients. This review focuses on colonic motility, manometry, operation, and motor patterns, and the clinical application of HRCM. Furthermore, the limitations, future directions, and potential usefulness of HRCM in the evaluation of clinical treatment effects are also discussed.
文摘Many fishes use undulatory fin to propel themselves in the underwater environment. These locomotor mechanisms have a popular interest to many researchers. In the present study, we perform a three-dimensional unsteady computation of an undulatory mechanical fin that is driven by Shape Memory Alloy （SMA）. The objective of the computation is to investigate the fluid dynamics of force production associated with the undulatory mechanical fin. An unstructured, grid-based, unsteady Navier-Stokes solver with automatic adaptive remeshing is used to compute the unsteady flow around the fin through five complete cycles. The pressure distribution on fin surface is computed and integrated to provide fin forces which are decomposed into lift and thrust. The velocity field is also computed throughout the swimming cycle. Finally, a comparison is conducted to reveal the dynamics of force generation according to the kinematic parameters of the undulatory fin （amplitude, frequency and wavelength）.
文摘BACKGROUND Neuroendocrine tumors(NETs)frequently occur in the gastrointestinal tract,lung,and pancreas,and the rectum and appendix are the sites with the highest incidence.Epidemiology statistics show that an estimated 8000 people every year in the United States are diagnosed with NETs occurring in the gastrointestinal tract,including the stomach,intestine,appendix,colon,and rectum.The pathological changes and clinical symptoms of NETs are not specific,and therefore they are frequently misdiagnosed.AIM To investigate the clinical symptoms,pathological characteristics,treatment,and prognosis of rectal neuroendocrine tumors(RNETs)by analyzing the clinical and pathological data of 132 RNET cases at our hospital.METHODS All RNETs were graded according to Ki-67 positivity and mitotic events.The tumors were staged as clinical stages I,II,III,and IV according to infiltrative depth and tumor size.COX proportional hazard model was used to assess the main risk factors for survival.RESULTS These 132 RNETs included 83 cases of G1,21 cases of G2,and 28 cases of G3(neuroendocrine carcinoma)disease.Immunohistochemical staining showed that 89.4%of RNETs were positive for synaptophysin and 39.4%positive for chromogranin A.There were 19,85,23,and 5 cases of clinical stages I,II,III,and IV,respectively.The median patient age was 52.96 years.The diameter of tumor,depth of invasion,and pathological grade were the main reference factors for the treatment of RNETs.The survival rates at 6,12,36,and 60 mo after operation were 98.5%,94.6%,90.2%,and 85.6%,respectively.Gender,tumor size,tumor grade,lymph node or distant organ metastasis,and radical resection were the main factors associated with prognosis of RNETs.Multivariate analysis showed that tumor size and grade were independent prognostic factors.CONCLUSION The clinical symptoms of RNETs are not specific,and they are easy to misdiagnose.Surgery is the main treatment method.The grade and stage of RNETs are the main indices to evaluate prognosis.
