Bioluminescence tomography(BLT)is an important noninvasive optical molecular imaging modality in preclinical research.To improve the image quality,reconstruction algorithms have to deal with the inherent ill-posedness...Bioluminescence tomography(BLT)is an important noninvasive optical molecular imaging modality in preclinical research.To improve the image quality,reconstruction algorithms have to deal with the inherent ill-posedness of BLT inverse problem.The sparse characteristic of bioluminescent sources in spatial distribution has been widely explored in BLT and many L1-regularized methods have been investigated due to the sparsity-inducing properties of L1 norm.In this paper,we present a reconstruction method based on L_(1/2) regularization to enhance sparsity of BLT solution and solve the nonconvex L_(1/2) norm problem by converting it to a series of weighted L1 homotopy minimization problems with iteratively updated weights.To assess the performance of the proposed reconstruction algorithm,simulations on a heterogeneous mouse model are designed to compare it with three representative sparse reconstruction algorithms,including the weighted interior-point,L1 homotopy,and the Stagewise Orthogonal Matching Pursuit algorithm.Simulation results show that the proposed method yield stable reconstruction results under different noise levels.Quantitative comparison results demonstrate that the proposed algorithm outperforms the competitor algorithms in location accuracy,multiple-source resolving and image quality.展开更多
A new dimeric Mn(Ⅱ) complex,namely,[Mn(L)(PIP)]_2·H_2O(1),was synthesized under hydrothermal condition(H_2L = 3-carboxy-1-carboxymethyl-2-oxidopyridinium and PIP = 2-(pyridin-3-yl)-1H-imidazo[4,5-f][1...A new dimeric Mn(Ⅱ) complex,namely,[Mn(L)(PIP)]_2·H_2O(1),was synthesized under hydrothermal condition(H_2L = 3-carboxy-1-carboxymethyl-2-oxidopyridinium and PIP = 2-(pyridin-3-yl)-1H-imidazo[4,5-f][1,10]phenanthroline).It crystallizes in triclinic,space group P1 with a = 9.2037(13),b = 9.6794(13),c = 14.649(3) A,α = 94.858(3),β = 94.928(3),γ = 114.468(2)o,V = 1172.9(3) A^3,Z = 1,C_(52)H_(34)Mn_2N_(12)O_(11),Mr = 1112.79,Dc = 1.575 g/cm^3,F(000) = 568,μ(Mo Ka) = 0.618 mm^-1,R = 0.0432 and w R = 0.1151.In 1,two L anions bridge two Mn(Ⅱ) atoms to give a dimeric [Mn(L)(PIP)] unit with the Mn···Mn distance of 3.009(2) A.The two PIP ligands are located on both sides of the dimer,which provides suitable π-π stacking interactions between PIP ligands.By these π-π stacking interactions,adjacent dimers are extended into a two-dimensional supramolecular layer.Further,the strong N–H···O hydrogen bond stabilizes the supramolecular layer structure of 1.Moreover,the thermal behavior and luminescent property of 1 have been studied.展开更多
A new Zn(Ⅱ) complex,[Zn(1,2,3-HBTC)(L)]2(1,L = 2-(2-chloro-6-fluorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline and 1,2,3-H3 BTC = 1,2,3-benzentricarboxylic acid),was synthesized under hydrothermal conditi...A new Zn(Ⅱ) complex,[Zn(1,2,3-HBTC)(L)]2(1,L = 2-(2-chloro-6-fluorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline and 1,2,3-H3 BTC = 1,2,3-benzentricarboxylic acid),was synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction.It crystallizes in triclinic,space group P1 with a = 10.455(2),b = 11.533(2),c = 12.499(3) A,α = 116.97(3),β = 94.08(3),γ = 103.29(3)o,V = 1280.2(4) A^3,Z = 1,C56H28Cl2F2N8O12Zn2,Mr = 1244.50,Dc = 1.614 g/cm^3,F(000) = 628,μ(Mo Ka) = 1.124 mm^-1,R = 0.0502 and w R = 0.1417.In compound 1,two 1,2,3-HBTC anions bridge two Zn(Ⅱ) atoms to give a dimeric structure with Zn···Zn distance of 3.15 A.Adjacent dimers interact through π-π stackings between two L ligands to result in a supramolecular layer.Moreover,N–H···O and O–H···N hydrogen bonds further stabilize the 2D supramolecular architecture of 1.In addition,the luminescent property of 1 has been studied.展开更多
AIM: To determine the effect of three digestive tract reconstruction procedures on pouch function, after radical surgery undertaken because of gastric cancer, as assessed by radionuclide dynamic imaging. METHODS: As a...AIM: To determine the effect of three digestive tract reconstruction procedures on pouch function, after radical surgery undertaken because of gastric cancer, as assessed by radionuclide dynamic imaging. METHODS: As a measure of the reservoir function, with a designed diet containing technetium-99m (99mTc), the emptying time of the gastric substitute was evaluated using a 99mTc-labeled solid test meal. Immediately after the meal, the patient was placed in front of a γ camera in a supine position and the radioactivity was measured over the whole abdomen every minute. A frame image was obtained. The emptying sequences were recorded by the microprocessor and then stored on a computer disk. According to a computer processing system, the half-emptying actual curve and the fitting curve of food containing isotope in the detected region were depicted, and the half-emptying actual curves of the three reconstruction procedures were directly compared. RESULTS: Of the three reconstruction procedures, the half-emptying time of food containing isotope in the Dual Braun type esophagojejunal anastomosis procedure (51.86±6.43 min) was far closer to normal, signif icantly better than that of the proximal gastrectomy orthotopic reconstruction (30.07±15.77 min, P=0.002) and P type esophagojejunal anastomosis (27.88±6.07 min, P=0.001) methods. The half-emptying actual curve and f itting curves for the Dual Braun type esophagojejunal anastomosis were fairly similar while those of the proximal gastrectomy orthotopic reconstruction and P type esophagojejunal anastomosis were obviously separated, which indicated bad food conservation in the reconstructed pouches. CONCLUSION: Dual Braun type esophagojejunal anastomosis is the most useful of the three procedures for improving food accommodation in patients with a pouch and can retard evacuation of solid food from the reconstructed pouch.展开更多
A new dimeric compound, [Zn(bpdc)(L)]2·4H2O(1, L = 11-fluoro-dipyrido[3,2-a:2',3'-c]phenazine and bpdc = 1,1'-biphenyl-2,2'-dicarboxylate), has been synthesized under hydrothermal conditions and charac...A new dimeric compound, [Zn(bpdc)(L)]2·4H2O(1, L = 11-fluoro-dipyrido[3,2-a:2',3'-c]phenazine and bpdc = 1,1'-biphenyl-2,2'-dicarboxylate), has been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction. It crystallizes in monoclinic, space group C2/c with a = 23.671(5), b = 22.547(5), c = 13.741(3)A, β = 123.47(3)°, V = 6118(2) A3, Z = 4, C66H44Cl2F2N8O12Zn2, Mr = 1380.73, Dc = 1.499 g/cm3, F(000) = 2816, μ(MoKa) = 0.949 mm-1, R = 0.0572 and wR = 0.1620. In 1, Zn1 and the symmetry formed Zn1 ions are connected by four bridging bidentate carboxylate groups from two independent bpdc anions to yield a binuclear unit with the Zn···Zn separation by bpdc anions of 4.168. Two L ligands are located on both sides of the dimer in chelating bidentate modes. The lateral L ligands from neighboring dimers are paired through strong π-π interactions to result in a fascinating 1D ladder-like supramolecular array. In addition, neighboring supramolecular ladders are packed each other to yield a 3D supramolecular architecture with a 1D channel.展开更多
By means of total energy calculations within the framework of the local density approximation (LDA), the interactions between a silicon Si(001) surface and a scanning probe are investigated. The tip of the probe, comp...By means of total energy calculations within the framework of the local density approximation (LDA), the interactions between a silicon Si(001) surface and a scanning probe are investigated. The tip of the probe, comprising 4 Si atoms scans along the dimer lines above an asymmetric p(2 × 1) surface, at a distance where the chemical interaction between tip-surface is dominant and responsible for image resolution. At that distance, the tip causes the dimer to toggle when it scans above the lower atom of a dimer. The toggled dimers create an alternating pattern, where the immediately adjacent neighbours of a toggled dimer remain unchanged. After the tip has fully scanned across the p(2 × 1) surface, causes the dimers to arrange in a p(2 × 2) reconstruction, reproducing the images obtained in scanning probe experiments. Our modelling methodology includes simulations that reveal the energy input required to overcome the barrier to the onset of dimer toggling. The results show that the energy input to overcome this barrier is lower for the p(2 × 1) surface than that for the p(2 × 2) or c(4 × 2) surfaces.展开更多
基金supported by the National Natural Science Foundation of China(No.61401264,11574192)the Natural Science Research Plan Program in Shaanxi Province of China(No.2015JM6322)the Fundamental Research Funds for the Central Universities(No.GK201603025).
文摘Bioluminescence tomography(BLT)is an important noninvasive optical molecular imaging modality in preclinical research.To improve the image quality,reconstruction algorithms have to deal with the inherent ill-posedness of BLT inverse problem.The sparse characteristic of bioluminescent sources in spatial distribution has been widely explored in BLT and many L1-regularized methods have been investigated due to the sparsity-inducing properties of L1 norm.In this paper,we present a reconstruction method based on L_(1/2) regularization to enhance sparsity of BLT solution and solve the nonconvex L_(1/2) norm problem by converting it to a series of weighted L1 homotopy minimization problems with iteratively updated weights.To assess the performance of the proposed reconstruction algorithm,simulations on a heterogeneous mouse model are designed to compare it with three representative sparse reconstruction algorithms,including the weighted interior-point,L1 homotopy,and the Stagewise Orthogonal Matching Pursuit algorithm.Simulation results show that the proposed method yield stable reconstruction results under different noise levels.Quantitative comparison results demonstrate that the proposed algorithm outperforms the competitor algorithms in location accuracy,multiple-source resolving and image quality.
基金Supported by the Institute Foundation of Siping city(No.2013036)
文摘A new dimeric Mn(Ⅱ) complex,namely,[Mn(L)(PIP)]_2·H_2O(1),was synthesized under hydrothermal condition(H_2L = 3-carboxy-1-carboxymethyl-2-oxidopyridinium and PIP = 2-(pyridin-3-yl)-1H-imidazo[4,5-f][1,10]phenanthroline).It crystallizes in triclinic,space group P1 with a = 9.2037(13),b = 9.6794(13),c = 14.649(3) A,α = 94.858(3),β = 94.928(3),γ = 114.468(2)o,V = 1172.9(3) A^3,Z = 1,C_(52)H_(34)Mn_2N_(12)O_(11),Mr = 1112.79,Dc = 1.575 g/cm^3,F(000) = 568,μ(Mo Ka) = 0.618 mm^-1,R = 0.0432 and w R = 0.1151.In 1,two L anions bridge two Mn(Ⅱ) atoms to give a dimeric [Mn(L)(PIP)] unit with the Mn···Mn distance of 3.009(2) A.The two PIP ligands are located on both sides of the dimer,which provides suitable π-π stacking interactions between PIP ligands.By these π-π stacking interactions,adjacent dimers are extended into a two-dimensional supramolecular layer.Further,the strong N–H···O hydrogen bond stabilizes the supramolecular layer structure of 1.Moreover,the thermal behavior and luminescent property of 1 have been studied.
基金Supported by the Institute Foundation of Siping City(No.2013036)
文摘A new Zn(Ⅱ) complex,[Zn(1,2,3-HBTC)(L)]2(1,L = 2-(2-chloro-6-fluorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline and 1,2,3-H3 BTC = 1,2,3-benzentricarboxylic acid),was synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction.It crystallizes in triclinic,space group P1 with a = 10.455(2),b = 11.533(2),c = 12.499(3) A,α = 116.97(3),β = 94.08(3),γ = 103.29(3)o,V = 1280.2(4) A^3,Z = 1,C56H28Cl2F2N8O12Zn2,Mr = 1244.50,Dc = 1.614 g/cm^3,F(000) = 628,μ(Mo Ka) = 1.124 mm^-1,R = 0.0502 and w R = 0.1417.In compound 1,two 1,2,3-HBTC anions bridge two Zn(Ⅱ) atoms to give a dimeric structure with Zn···Zn distance of 3.15 A.Adjacent dimers interact through π-π stackings between two L ligands to result in a supramolecular layer.Moreover,N–H···O and O–H···N hydrogen bonds further stabilize the 2D supramolecular architecture of 1.In addition,the luminescent property of 1 has been studied.
文摘AIM: To determine the effect of three digestive tract reconstruction procedures on pouch function, after radical surgery undertaken because of gastric cancer, as assessed by radionuclide dynamic imaging. METHODS: As a measure of the reservoir function, with a designed diet containing technetium-99m (99mTc), the emptying time of the gastric substitute was evaluated using a 99mTc-labeled solid test meal. Immediately after the meal, the patient was placed in front of a γ camera in a supine position and the radioactivity was measured over the whole abdomen every minute. A frame image was obtained. The emptying sequences were recorded by the microprocessor and then stored on a computer disk. According to a computer processing system, the half-emptying actual curve and the fitting curve of food containing isotope in the detected region were depicted, and the half-emptying actual curves of the three reconstruction procedures were directly compared. RESULTS: Of the three reconstruction procedures, the half-emptying time of food containing isotope in the Dual Braun type esophagojejunal anastomosis procedure (51.86±6.43 min) was far closer to normal, signif icantly better than that of the proximal gastrectomy orthotopic reconstruction (30.07±15.77 min, P=0.002) and P type esophagojejunal anastomosis (27.88±6.07 min, P=0.001) methods. The half-emptying actual curve and f itting curves for the Dual Braun type esophagojejunal anastomosis were fairly similar while those of the proximal gastrectomy orthotopic reconstruction and P type esophagojejunal anastomosis were obviously separated, which indicated bad food conservation in the reconstructed pouches. CONCLUSION: Dual Braun type esophagojejunal anastomosis is the most useful of the three procedures for improving food accommodation in patients with a pouch and can retard evacuation of solid food from the reconstructed pouch.
基金Supported by the Science and Technology Research Projects of the Education Committee of Jilin Province(No.2014150)
文摘A new dimeric compound, [Zn(bpdc)(L)]2·4H2O(1, L = 11-fluoro-dipyrido[3,2-a:2',3'-c]phenazine and bpdc = 1,1'-biphenyl-2,2'-dicarboxylate), has been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction. It crystallizes in monoclinic, space group C2/c with a = 23.671(5), b = 22.547(5), c = 13.741(3)A, β = 123.47(3)°, V = 6118(2) A3, Z = 4, C66H44Cl2F2N8O12Zn2, Mr = 1380.73, Dc = 1.499 g/cm3, F(000) = 2816, μ(MoKa) = 0.949 mm-1, R = 0.0572 and wR = 0.1620. In 1, Zn1 and the symmetry formed Zn1 ions are connected by four bridging bidentate carboxylate groups from two independent bpdc anions to yield a binuclear unit with the Zn···Zn separation by bpdc anions of 4.168. Two L ligands are located on both sides of the dimer in chelating bidentate modes. The lateral L ligands from neighboring dimers are paired through strong π-π interactions to result in a fascinating 1D ladder-like supramolecular array. In addition, neighboring supramolecular ladders are packed each other to yield a 3D supramolecular architecture with a 1D channel.
文摘By means of total energy calculations within the framework of the local density approximation (LDA), the interactions between a silicon Si(001) surface and a scanning probe are investigated. The tip of the probe, comprising 4 Si atoms scans along the dimer lines above an asymmetric p(2 × 1) surface, at a distance where the chemical interaction between tip-surface is dominant and responsible for image resolution. At that distance, the tip causes the dimer to toggle when it scans above the lower atom of a dimer. The toggled dimers create an alternating pattern, where the immediately adjacent neighbours of a toggled dimer remain unchanged. After the tip has fully scanned across the p(2 × 1) surface, causes the dimers to arrange in a p(2 × 2) reconstruction, reproducing the images obtained in scanning probe experiments. Our modelling methodology includes simulations that reveal the energy input required to overcome the barrier to the onset of dimer toggling. The results show that the energy input to overcome this barrier is lower for the p(2 × 1) surface than that for the p(2 × 2) or c(4 × 2) surfaces.