Silicon nanomaterials have been of immense interest in the last few decades due to their remarkable optoelectronic responses,elemental abundance,and higher biocompatibility.Two-dimensional silicon is one of the new al...Silicon nanomaterials have been of immense interest in the last few decades due to their remarkable optoelectronic responses,elemental abundance,and higher biocompatibility.Two-dimensional silicon is one of the new allotropes of silicon and has many compelling properties such as quantum-confined photoluminescence,high charge carrier mobilities,anisotropic electronic and magnetic response,and non-linear optical properties.This review summarizes the recent advances in the synthesis of two-dimensional silicon nanomaterials with a range of structures(silicene,silicane,and multilayered silicon),surface ligand engineering,and corresponding optoelectronic applications.展开更多
In this Keynote lecture,we review the main known features of MHD turbulence at low magnetic Reynolds number,that is when the flow isn't intense enough to disturb an externally applied magnetic field.The emphasis i...In this Keynote lecture,we review the main known features of MHD turbulence at low magnetic Reynolds number,that is when the flow isn't intense enough to disturb an externally applied magnetic field.The emphasis is deliberately placed on the very specific physical mechanisms of this type of flows,rather than their numerical modelling. We also focus on homogeneous magnetic fields which have received most attention.We stress in particular that the tendency to two-dimensionality observed in these flows casts the boundaries of the domain into a leading role.展开更多
Background Assessment of the left ventricular (LV) and the right ventricular (RV) volumes and their functions is important for prognostic prediction and clinical decision making. We compared the accuracy for quantify...Background Assessment of the left ventricular (LV) and the right ventricular (RV) volumes and their functions is important for prognostic prediction and clinical decision making. We compared the accuracy for quantifying the LV and the RV volumes in vitro between conventional two-dimensional echocardiography (2DE) and real-time three-dimensional echocardiography (RT3DE) Methods The volumes of 37 rubber-models (10 regularly shaped to simulate normal LV, 7 shaped to simulate LV with symmetric aneurysm, 8 shaped to simulate LV with asymmetric aneurysm, and 12 irregularly shaped to simulate normal RV) and 10 excised canine hearts were measured by RT3DE and 2DE On RT3DE 'full volume' imaging, the inner-surfaces of the rubber-models and canine LV and RV were outlined and the volumes were measured using 2-, 4-, 8- and 16-plane methods with the RT3DE analysis software On 2DE imaging, the volumes were measured by the Simpson method The LV and RV volumes measured by drained water were served as reference values, with which we compared RT3DE and 2DE data Results In rubber models mimicking normal LV and LV with symmetric aneurysms, RT3DE results were strongly correlated with reference values ( r =0 795-0 998) and there was a good correlation between 2DE estimates and reference values ( r =0 715-0 729) There were no significant differences between RT3DE estimates, 2DE results and reference values ( P >0 05) In rubber models mimicking the RV and LV with asymmetric aneurysm, RT3DE strongly correlated with reference values ( r =0 765-0 988), but 2DE weakly correlated with reference values ( r =0 518-0 592) There were no differences between RT3DE and reference values ( P >0 05), but a significant difference between 2DE and reference values occurred ( P <0 05) For excised canine hearts, there was a strong correlation between RT3DE and reference values ( r =0 728-0 914), while 2DE showed a less obvious correlation ( r =0 502-0 615) Again, there were no significant differenc展开更多
Two-dimensional materials having a layered structure comprise a monolayer or multilayers of atomic thickness and ultra-low shear strength.Their high specific surface area,in-plane strength,weak layer-layer interaction...Two-dimensional materials having a layered structure comprise a monolayer or multilayers of atomic thickness and ultra-low shear strength.Their high specific surface area,in-plane strength,weak layer-layer interaction,and surface chemical stability result in remarkably low friction and wear-resisting properties.Thus,2D materials have attracted considerable attention.In recent years,great advances have been made in the scientific research and industrial applications of anti-friction,anti-wear,and lubrication of 2D materials.In this article,the basic nanoscale friction mechanisms of 2D materials including interfacial friction and surface friction mechanisms are summarized.This paper also includes a review of reports on lubrication mechanisms based on the film-formation,self-healing,and ball bearing mechanisms and applications based on lubricant additives,nanoscale lubricating films,and space lubrication materials of 2D materials in detail.Finally,the challenges and potential applications of 2D materials in the field of lubrication were also presented.展开更多
AIM: To investigate the value of two-dimensional (2D) and three-dimensional (3D) double contrast-enhanced ultrasonography (DCUS) imaging for evaluation of gas- tric lesions. METHODS: 2D and 3D DCUS imaging wit...AIM: To investigate the value of two-dimensional (2D) and three-dimensional (3D) double contrast-enhanced ultrasonography (DCUS) imaging for evaluation of gas- tric lesions. METHODS: 2D and 3D DCUS imaging with both oral and intravenous administrations of contrast agents was used to assess gastroscopiclly-confirmed gastric lesions in 46 patients with benign and malignant diseases. Initially, liquid-based ultrasound contrast agent (Xinzhang) was given orally at dose of 500-600 mL for conventional ultrasound examination of the gastric lesions, and then a microbubble-based contrast agent (SonoVue) was injected intravenously at dose of 1.2-2.4 mL in bolus fashion to assess the perfusion pattern of the lesions using contrast imaging modes. The parameters derived from time-intensity curves including the arrival time (AT), time to peak (lq-P), peak intensity (PI) and en- hanced intensity (EI) were measured on the 2D DCUS imaging. 3D DCUS of the lesions was acquired to dem- onstrate the value of this imaging mode. RESULTS: There were 22 cases with benign lesions including chronic gastritis (n= 5), gastric ulcer (n = 9), gastric polyps (n = 3), gastric stromal tumors (n = 5), and 24 cases with malignant lesions including gastric cancer (n = 20), gastric cardia carcinoma (n = 3) and post-operative recurrent gastric cancer (n = 1) in the study, The oral contrast-enhanced ultrasonography (CEUS) imaging of the stomach clearly demonstrated the anatomy of the stomach and morphologic features of gastric lesions, With optimal scanning window and imaging display under oral CEUS, intravenous CEUS clearly showed the perfusion of gastric lesions with various characteristic manifestations. Both 2D and 3D DCUS images clearly demonstrated normal gastric wall as a three-layer structure, from the inside out, hypere- choic mucosa, hypoechoic muscularis and hyperechoic serosa, respectively. There were statistical significant differences of AT (8.68±2.06 vs 10.43 ±展开更多
We have calculated the longitudinal acoustic phonon limited electron mobility of 14 twvo-dimensional semiconductors with composition of MX2, where M (= Mo, W, Sn, Hf, Zr and Pt) is the transition metal, and X is S, ...We have calculated the longitudinal acoustic phonon limited electron mobility of 14 twvo-dimensional semiconductors with composition of MX2, where M (= Mo, W, Sn, Hf, Zr and Pt) is the transition metal, and X is S, Se and Te. We treated the scattering matrix by the deformation potential approximation. We found that out of 14 compounds, MoTe2, HfSe2 and ZrSe2 are promising regarding to their possible high mobility and finite band gap. The phonon limited mobility can be above 2,500 cm^2·V^-1·s^-1 at room temperature.展开更多
In recent years, a new 2D-layered material—black phosphorus(BP)—has been a rising star after the era of graphene owing to its high charge carrier mobility, tunable direct bandgap and unique in-plane anisotropic stru...In recent years, a new 2D-layered material—black phosphorus(BP)—has been a rising star after the era of graphene owing to its high charge carrier mobility, tunable direct bandgap and unique in-plane anisotropic structure. With the development of the synthesis and modification methods of BP, its extensive applications, e.g., transistors, batteries and optoelectronics have emerged. In order to explore its full potential, research into the tribological properties of BP 2D-layered materials such as lubrication additives and fillers in self-lubricating composite materials would be not only of high scientific value but also of practical significance. In this work, recent advances on the friction and lubrication properties of BP nanosheets made by our group, including the micro-friction properties, the lubrication properties of BP nanosheets as water-based and oil-based lubrication additives, and the friction and wear of BP/PVDF composites will be presented. Finally, the future challenges and opportunities in the use of BP materials as lubricants will be discussed.展开更多
The synthesis of two-dimensional (2D) layered materials with controllable thickness is of considerable interest for diverse applications. Here we report the first chemical vapor deposition growth of single- and few-...The synthesis of two-dimensional (2D) layered materials with controllable thickness is of considerable interest for diverse applications. Here we report the first chemical vapor deposition growth of single- and few-layer MoSe2 nanosheets. By using Se and MoO3 as the chemical vapor supply, we demonstrate that highly crystalline MoSe2 can be directly grown on the 300 nm SiO2/Si substrates to form optically distinguishable single- and multi-layer nanosheets, typically in triangular shaped domains with edge lengths around 30 btm, which can merge into continuous thin films upon further growth. Micro-Raman spectroscopy and imaging was used to probe the thickness-dependent vibrational properties. Photoluminescence spectroscopy demonstrates that MoSe2 monolayers exhibit strong near band edge emission at 1.55 eV, while bilayers or multi-layers exhibit much weaker emission, indicating of the transition to a direct band gap semiconductor as the thickness is reduced to a monolayer.展开更多
BACKGROUND: Pancreatic cancer is one of the most common malignant tumors. Early diagnosis of pancreatic cancer is difficult because of the latent onset and lack of good biomarkers. This study aimed to look for and ide...BACKGROUND: Pancreatic cancer is one of the most common malignant tumors. Early diagnosis of pancreatic cancer is difficult because of the latent onset and lack of good biomarkers. This study aimed to look for and identify differentially expressed proteins in tissues of pancreatic cancer and adjacent noncancerous tissues by proteomic approaches so as to provide information about possible pancreatic cancer markers and therapeutic targets. METHODS: Proteins extracted front 3 paired adjacent noncancerous and cancerous pancreatic tissue specimens were separated by two-dimensional gel electrophoresis (2-DE). The protein spots exhibiting statistical alternations between the two groups through computerized image analysis were then identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). In addition, Western blotting and immunohistochemistry were performed to verify the expression of certain candidate proteins. RESULTS: Twelve proteins were significantly upregulated and 4 were downregulated between cancerous and paired adjacent noncancerous pancreatic tissues. Several proteins (S100A11, Ig gamma-l chain C region, GSTO1 and peroxiredoxin 4) were found for the first time to be associated with pancreatic cancer. Differential expression of some identified proteins was further confirmed by Western blotting analysis and/or immunohistochemical analysis. CONCLUSIONS: Comparative proteomic analysis using 2-DE and MALDI-TOF-MS is an effective method for identifying differentially expressed proteins that may be the potential diagnostic biomarkers and therapeutic targets for pancreatic cancer.展开更多
基金the National Natural Science Foundation of China(21905316,22175201)Guangdong Natural Science Foundation(2019A1515011748)+1 种基金the Science and Technology Planning Project of Guangdong Province(2019A050510018)Sun Yat-sen University.
文摘Silicon nanomaterials have been of immense interest in the last few decades due to their remarkable optoelectronic responses,elemental abundance,and higher biocompatibility.Two-dimensional silicon is one of the new allotropes of silicon and has many compelling properties such as quantum-confined photoluminescence,high charge carrier mobilities,anisotropic electronic and magnetic response,and non-linear optical properties.This review summarizes the recent advances in the synthesis of two-dimensional silicon nanomaterials with a range of structures(silicene,silicane,and multilayered silicon),surface ligand engineering,and corresponding optoelectronic applications.
文摘In this Keynote lecture,we review the main known features of MHD turbulence at low magnetic Reynolds number,that is when the flow isn't intense enough to disturb an externally applied magnetic field.The emphasis is deliberately placed on the very specific physical mechanisms of this type of flows,rather than their numerical modelling. We also focus on homogeneous magnetic fields which have received most attention.We stress in particular that the tendency to two-dimensionality observed in these flows casts the boundaries of the domain into a leading role.
文摘Background Assessment of the left ventricular (LV) and the right ventricular (RV) volumes and their functions is important for prognostic prediction and clinical decision making. We compared the accuracy for quantifying the LV and the RV volumes in vitro between conventional two-dimensional echocardiography (2DE) and real-time three-dimensional echocardiography (RT3DE) Methods The volumes of 37 rubber-models (10 regularly shaped to simulate normal LV, 7 shaped to simulate LV with symmetric aneurysm, 8 shaped to simulate LV with asymmetric aneurysm, and 12 irregularly shaped to simulate normal RV) and 10 excised canine hearts were measured by RT3DE and 2DE On RT3DE 'full volume' imaging, the inner-surfaces of the rubber-models and canine LV and RV were outlined and the volumes were measured using 2-, 4-, 8- and 16-plane methods with the RT3DE analysis software On 2DE imaging, the volumes were measured by the Simpson method The LV and RV volumes measured by drained water were served as reference values, with which we compared RT3DE and 2DE data Results In rubber models mimicking normal LV and LV with symmetric aneurysms, RT3DE results were strongly correlated with reference values ( r =0 795-0 998) and there was a good correlation between 2DE estimates and reference values ( r =0 715-0 729) There were no significant differences between RT3DE estimates, 2DE results and reference values ( P >0 05) In rubber models mimicking the RV and LV with asymmetric aneurysm, RT3DE strongly correlated with reference values ( r =0 765-0 988), but 2DE weakly correlated with reference values ( r =0 518-0 592) There were no differences between RT3DE and reference values ( P >0 05), but a significant difference between 2DE and reference values occurred ( P <0 05) For excised canine hearts, there was a strong correlation between RT3DE and reference values ( r =0 728-0 914), while 2DE showed a less obvious correlation ( r =0 502-0 615) Again, there were no significant differenc
基金supported by the National Natural Science Foundation of China(Grant No.51505442)Guangxi Natural Science Foundation(Grant No.2018GXNSFAA138174)
文摘Two-dimensional materials having a layered structure comprise a monolayer or multilayers of atomic thickness and ultra-low shear strength.Their high specific surface area,in-plane strength,weak layer-layer interaction,and surface chemical stability result in remarkably low friction and wear-resisting properties.Thus,2D materials have attracted considerable attention.In recent years,great advances have been made in the scientific research and industrial applications of anti-friction,anti-wear,and lubrication of 2D materials.In this article,the basic nanoscale friction mechanisms of 2D materials including interfacial friction and surface friction mechanisms are summarized.This paper also includes a review of reports on lubrication mechanisms based on the film-formation,self-healing,and ball bearing mechanisms and applications based on lubricant additives,nanoscale lubricating films,and space lubrication materials of 2D materials in detail.Finally,the challenges and potential applications of 2D materials in the field of lubrication were also presented.
基金Supported by A key medical project in Nanjing Military District of the Chinese People’s Liberation Army,No. 09Z039
文摘AIM: To investigate the value of two-dimensional (2D) and three-dimensional (3D) double contrast-enhanced ultrasonography (DCUS) imaging for evaluation of gas- tric lesions. METHODS: 2D and 3D DCUS imaging with both oral and intravenous administrations of contrast agents was used to assess gastroscopiclly-confirmed gastric lesions in 46 patients with benign and malignant diseases. Initially, liquid-based ultrasound contrast agent (Xinzhang) was given orally at dose of 500-600 mL for conventional ultrasound examination of the gastric lesions, and then a microbubble-based contrast agent (SonoVue) was injected intravenously at dose of 1.2-2.4 mL in bolus fashion to assess the perfusion pattern of the lesions using contrast imaging modes. The parameters derived from time-intensity curves including the arrival time (AT), time to peak (lq-P), peak intensity (PI) and en- hanced intensity (EI) were measured on the 2D DCUS imaging. 3D DCUS of the lesions was acquired to dem- onstrate the value of this imaging mode. RESULTS: There were 22 cases with benign lesions including chronic gastritis (n= 5), gastric ulcer (n = 9), gastric polyps (n = 3), gastric stromal tumors (n = 5), and 24 cases with malignant lesions including gastric cancer (n = 20), gastric cardia carcinoma (n = 3) and post-operative recurrent gastric cancer (n = 1) in the study, The oral contrast-enhanced ultrasonography (CEUS) imaging of the stomach clearly demonstrated the anatomy of the stomach and morphologic features of gastric lesions, With optimal scanning window and imaging display under oral CEUS, intravenous CEUS clearly showed the perfusion of gastric lesions with various characteristic manifestations. Both 2D and 3D DCUS images clearly demonstrated normal gastric wall as a three-layer structure, from the inside out, hypere- choic mucosa, hypoechoic muscularis and hyperechoic serosa, respectively. There were statistical significant differences of AT (8.68±2.06 vs 10.43 ±
文摘We have calculated the longitudinal acoustic phonon limited electron mobility of 14 twvo-dimensional semiconductors with composition of MX2, where M (= Mo, W, Sn, Hf, Zr and Pt) is the transition metal, and X is S, Se and Te. We treated the scattering matrix by the deformation potential approximation. We found that out of 14 compounds, MoTe2, HfSe2 and ZrSe2 are promising regarding to their possible high mobility and finite band gap. The phonon limited mobility can be above 2,500 cm^2·V^-1·s^-1 at room temperature.
基金support of the National Natural Science Foundation of China(Grant Nos.51527901,51335005,51475256,and 51605249)
文摘In recent years, a new 2D-layered material—black phosphorus(BP)—has been a rising star after the era of graphene owing to its high charge carrier mobility, tunable direct bandgap and unique in-plane anisotropic structure. With the development of the synthesis and modification methods of BP, its extensive applications, e.g., transistors, batteries and optoelectronics have emerged. In order to explore its full potential, research into the tribological properties of BP 2D-layered materials such as lubrication additives and fillers in self-lubricating composite materials would be not only of high scientific value but also of practical significance. In this work, recent advances on the friction and lubrication properties of BP nanosheets made by our group, including the micro-friction properties, the lubrication properties of BP nanosheets as water-based and oil-based lubrication additives, and the friction and wear of BP/PVDF composites will be presented. Finally, the future challenges and opportunities in the use of BP materials as lubricants will be discussed.
文摘The synthesis of two-dimensional (2D) layered materials with controllable thickness is of considerable interest for diverse applications. Here we report the first chemical vapor deposition growth of single- and few-layer MoSe2 nanosheets. By using Se and MoO3 as the chemical vapor supply, we demonstrate that highly crystalline MoSe2 can be directly grown on the 300 nm SiO2/Si substrates to form optically distinguishable single- and multi-layer nanosheets, typically in triangular shaped domains with edge lengths around 30 btm, which can merge into continuous thin films upon further growth. Micro-Raman spectroscopy and imaging was used to probe the thickness-dependent vibrational properties. Photoluminescence spectroscopy demonstrates that MoSe2 monolayers exhibit strong near band edge emission at 1.55 eV, while bilayers or multi-layers exhibit much weaker emission, indicating of the transition to a direct band gap semiconductor as the thickness is reduced to a monolayer.
文摘BACKGROUND: Pancreatic cancer is one of the most common malignant tumors. Early diagnosis of pancreatic cancer is difficult because of the latent onset and lack of good biomarkers. This study aimed to look for and identify differentially expressed proteins in tissues of pancreatic cancer and adjacent noncancerous tissues by proteomic approaches so as to provide information about possible pancreatic cancer markers and therapeutic targets. METHODS: Proteins extracted front 3 paired adjacent noncancerous and cancerous pancreatic tissue specimens were separated by two-dimensional gel electrophoresis (2-DE). The protein spots exhibiting statistical alternations between the two groups through computerized image analysis were then identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). In addition, Western blotting and immunohistochemistry were performed to verify the expression of certain candidate proteins. RESULTS: Twelve proteins were significantly upregulated and 4 were downregulated between cancerous and paired adjacent noncancerous pancreatic tissues. Several proteins (S100A11, Ig gamma-l chain C region, GSTO1 and peroxiredoxin 4) were found for the first time to be associated with pancreatic cancer. Differential expression of some identified proteins was further confirmed by Western blotting analysis and/or immunohistochemical analysis. CONCLUSIONS: Comparative proteomic analysis using 2-DE and MALDI-TOF-MS is an effective method for identifying differentially expressed proteins that may be the potential diagnostic biomarkers and therapeutic targets for pancreatic cancer.