MM： To evaluate the maximal-outer-diameter （MOD） and the maximal-mural-thickness （MMT） of the appendix in children with acute appendicitis and to determine their optimal cut-off values to diagnose acute appendici...MM： To evaluate the maximal-outer-diameter （MOD） and the maximal-mural-thickness （MMT） of the appendix in children with acute appendicitis and to determine their optimal cut-off values to diagnose acute appendicitis.METHODS： In total, 164 appendixes from 160 children between 1 and 17 years old （84 males, 76 females; mean age, 7.38 years） were examined by high-resolution abdominal ultrasound for acute abdominal pain and the suspicion of acute appendicitis. We measured the MOD and the MMT at the thickest point of the appendix. Patients were categorized into two groups according to their medical records： patients who had surgery （surgical appendix group） and patients who did not have surgery （non-surgical appendix group）. Data were analyzed by MedCalc v.9.3. The rank sum test （Mann-Whitney test） was used to evaluate the difference in the MOD and the MMT between the two groups. ROC curve analysis was used to determine the optimal cut-off value of the MOD and the MMT on diagnosis of acute appendicitis.RESULTS： There were 121 appendixes （73.8%） in the non-surgical appendix group and 43 appendixes （26.2%） in the surgical appendix group. The median MOD differed significantly between the two groups （0.37 cm vs 0.76 cm, P〈 0.0001）, and the median MMT also differed （0.15 cm vs 0.33 cm, P 〈 0.0001）. The optimal cut-off value of the MOD and the MMT for diagnosis of acute appendicitis in children was 〉 0.57 cm （sensitivity 95.4%, specificity 93.4%） and 〉 0.22 cm （sensitivity 90.7%, specificity 79.3%）, respectively.CONCLUSION： The MOD and the MMT are reliable criteria to diagnose acute appendicitis in children. An MOD 〉 0.57 cm and an MMT 〉 0.22 cm are the optimal criteria.展开更多
In this paper,a kind of composite microtube,which is made from superfine silk powder and polyurethane,reinforced by polyster and spandex tubular fabrics,was examined.The cross-section of composite microtubes were micr...In this paper,a kind of composite microtube,which is made from superfine silk powder and polyurethane,reinforced by polyster and spandex tubular fabrics,was examined.The cross-section of composite microtubes were microporous,and micropores were uniform distributed,the inner surface was relatively smooth.The results showed that the wall thickness of composite microtubes increased,which led to the strength,the breaking work and the initial modulus incresead;that the spandex content increased brought about the initial modulus and the breaking work decreased,but the breaking extension and the breaking load were firstly increased and then decreased;and all the mechanical properties decreased as the SFSP content increased.展开更多
Strain engineering is a powerful tool to tailor the physical properties of materials coherently stacked in an epitaxial heterostructure. Such an approach, applied to the mature field of planar heteroepitaxy, has yield...Strain engineering is a powerful tool to tailor the physical properties of materials coherently stacked in an epitaxial heterostructure. Such an approach, applied to the mature field of planar heteroepitaxy, has yielded a variety of new phenomena and devices. Recently, heteroepitaxial vertically aligned nanocomposites have emerged as alternatives to planar structures. Owing to the peculiar geometry of such nanoarchitectures, efficient strain control can be achieved, opening the way to novel functionalities. In this paper, we report a very large tensile axial strain in epitaxial transition metal nanowires embedded in an oxide matrix. We show that axial strains in excess of 1.5% can be sustained over a large thickness （a few hundred nanometers） in epitaxial nanowires having ultrasmall diameters （-3-6 nm）. The axial strain depends on the diameter of the nanowires, reflecting its epitaxial nature and the balance of interface and elastic energies. Furthermore, it is experimentally shown that such strain is metastable, in agreement with the calculations performed in the framework of the Frenkel-Kontorova model. The diameter dependence and metastability provide effective ways to control the strain, an appealing feature for the design of functional nanoarchitectures.展开更多
文摘MM： To evaluate the maximal-outer-diameter （MOD） and the maximal-mural-thickness （MMT） of the appendix in children with acute appendicitis and to determine their optimal cut-off values to diagnose acute appendicitis.METHODS： In total, 164 appendixes from 160 children between 1 and 17 years old （84 males, 76 females; mean age, 7.38 years） were examined by high-resolution abdominal ultrasound for acute abdominal pain and the suspicion of acute appendicitis. We measured the MOD and the MMT at the thickest point of the appendix. Patients were categorized into two groups according to their medical records： patients who had surgery （surgical appendix group） and patients who did not have surgery （non-surgical appendix group）. Data were analyzed by MedCalc v.9.3. The rank sum test （Mann-Whitney test） was used to evaluate the difference in the MOD and the MMT between the two groups. ROC curve analysis was used to determine the optimal cut-off value of the MOD and the MMT on diagnosis of acute appendicitis.RESULTS： There were 121 appendixes （73.8%） in the non-surgical appendix group and 43 appendixes （26.2%） in the surgical appendix group. The median MOD differed significantly between the two groups （0.37 cm vs 0.76 cm, P〈 0.0001）, and the median MMT also differed （0.15 cm vs 0.33 cm, P 〈 0.0001）. The optimal cut-off value of the MOD and the MMT for diagnosis of acute appendicitis in children was 〉 0.57 cm （sensitivity 95.4%, specificity 93.4%） and 〉 0.22 cm （sensitivity 90.7%, specificity 79.3%）, respectively.CONCLUSION： The MOD and the MMT are reliable criteria to diagnose acute appendicitis in children. An MOD 〉 0.57 cm and an MMT 〉 0.22 cm are the optimal criteria.
基金State Natural Sciences Fundgrant number:50873079+1 种基金National Major Foudamental Research Program of Chinagrant number:2009CB526402
文摘In this paper,a kind of composite microtube,which is made from superfine silk powder and polyurethane,reinforced by polyster and spandex tubular fabrics,was examined.The cross-section of composite microtubes were microporous,and micropores were uniform distributed,the inner surface was relatively smooth.The results showed that the wall thickness of composite microtubes increased,which led to the strength,the breaking work and the initial modulus incresead;that the spandex content increased brought about the initial modulus and the breaking work decreased,but the breaking extension and the breaking load were firstly increased and then decreased;and all the mechanical properties decreased as the SFSP content increased.
文摘Strain engineering is a powerful tool to tailor the physical properties of materials coherently stacked in an epitaxial heterostructure. Such an approach, applied to the mature field of planar heteroepitaxy, has yielded a variety of new phenomena and devices. Recently, heteroepitaxial vertically aligned nanocomposites have emerged as alternatives to planar structures. Owing to the peculiar geometry of such nanoarchitectures, efficient strain control can be achieved, opening the way to novel functionalities. In this paper, we report a very large tensile axial strain in epitaxial transition metal nanowires embedded in an oxide matrix. We show that axial strains in excess of 1.5% can be sustained over a large thickness （a few hundred nanometers） in epitaxial nanowires having ultrasmall diameters （-3-6 nm）. The axial strain depends on the diameter of the nanowires, reflecting its epitaxial nature and the balance of interface and elastic energies. Furthermore, it is experimentally shown that such strain is metastable, in agreement with the calculations performed in the framework of the Frenkel-Kontorova model. The diameter dependence and metastability provide effective ways to control the strain, an appealing feature for the design of functional nanoarchitectures.
