Nuclear magnetic resonance (NMR) relaxation of fluids in porous media is affected by the solid-liquid interface. Quantitative determination of the surface relaxivity is significantly important for both investigation a...Nuclear magnetic resonance (NMR) relaxation of fluids in porous media is affected by the solid-liquid interface. Quantitative determination of the surface relaxivity is significantly important for both investigation and application of relaxation mechanisms in porous media. A method to estimate the surface relaxivity with the combination of relaxation and diffusion measurements is proposed. According to this method, a criterion for testing the current diffusion and relaxation theory for porous media is available.展开更多
Synthesis of ligand, α-oxo-pentanedioic acid benzoyl hydrazone (H2LPB), and its six rare earth (La, Pr, Nd, Sm, Gd and Er) complexes are reported. The composition and the properties of the complexes were characterize...Synthesis of ligand, α-oxo-pentanedioic acid benzoyl hydrazone (H2LPB), and its six rare earth (La, Pr, Nd, Sm, Gd and Er) complexes are reported. The composition and the properties of the complexes were characterized by element analysis, thermal analysis, UV, IR and H NMR spectra. Besides, relaxivity (R1) of Gd-complex has been determined by INVREC.Au program, using inversion recovery pulse sequences, R1=8.05 mmol ·L-1 · s-1. The acute toxicity of Gd-complex in animal has also been tested, and the median lethal dose (LD50) is equal to (468.2±30) mg/kg.展开更多
Five DTPA bis(amide)s have been synthesized and characterized by means of 1 H NMR , FT IR and elemental analyses. The stability constants of their Gd 3+ complexes have been measured using a simple spec...Five DTPA bis(amide)s have been synthesized and characterized by means of 1 H NMR , FT IR and elemental analyses. The stability constants of their Gd 3+ complexes have been measured using a simple spectrophotometric method. The results show that the complexing properties of the ligands in comparison with those of DTPA are affected by converting two carboxyl groups to amide groups. The relaxation studies have shown that the relaxivity of the chelates is similar to that of Gd DTPA, indicating that in solution all the chelates have one water molecule directly coordinated to the metal ion. Only one water molecule in inner coordination sphere suggests the coordination of the carboxamide oxygen to gadolinium ion, which agrees with the FT IR results.展开更多
It is greatly desired to develop novel gadolinium-based contrast agents(GBCAs)as improved platforms for magnetic resonance imaging(MRI).Herein,we report the syntheses of a series of nonionic cyclenbased GBCAs by preci...It is greatly desired to develop novel gadolinium-based contrast agents(GBCAs)as improved platforms for magnetic resonance imaging(MRI).Herein,we report the syntheses of a series of nonionic cyclenbased GBCAs by precisely tuning carboxylate group on DO3A-pyridine scaffold.[Gd-DO3A-4cp]is isolated which adopts an octadentate coordination mode with a free carboxylate group at 4-position of pyridine.It shows the r_(1)relaxivity of 5.8(mmol/L)^(-1)s^(-1)(3 T,25℃),which is 75%higher than 3.3(mmol/L)^(-1)s^(-1)of the clinic used[Gd-DOTA].The possible mechanisms behind the enhanced relaxivity are investigated and proposed by structure-property relationship studies.After validation of low cytotoxicity and considerable kinetic inertness,in-vivo studies are further examined,demonstrating its good MRI performance,biodistribution as well as the way of excretion.展开更多
DTPA was covalently conjugated to the copolymer of L lysine and L tyrosine, then transchelated with Gd EDTA,the resultant polymer chelates were further reacted with 6 O bromoacetyl D galacto...DTPA was covalently conjugated to the copolymer of L lysine and L tyrosine, then transchelated with Gd EDTA,the resultant polymer chelates were further reacted with 6 O bromoacetyl D galactose or methyl lactobionyloxyacetate to give PLT(Gd DTPA) with galactose moiety as liver targeting group.These macromolecular MRI contrast agents were characterized by means of FT IR, ICP AES, elementary analyses and UV Vis spectrophotometry. Their in vitro relaxivity and liver targeting property in mice were also investigated.展开更多
文摘Nuclear magnetic resonance (NMR) relaxation of fluids in porous media is affected by the solid-liquid interface. Quantitative determination of the surface relaxivity is significantly important for both investigation and application of relaxation mechanisms in porous media. A method to estimate the surface relaxivity with the combination of relaxation and diffusion measurements is proposed. According to this method, a criterion for testing the current diffusion and relaxation theory for porous media is available.
基金Project supported by the Natural Science Foundation in Jiangsu Province(No.17KJB320001)the Top-notch Academic Programs Project of Jiangsu Higher Education Institutions(No.PPZY2015B179)+1 种基金the Training Program of Students Innovation and Entrepreneurship in Jiangsu Province(No.201712920001Y)the Qing Lan Project of Jiangsu Province~~
文摘Synthesis of ligand, α-oxo-pentanedioic acid benzoyl hydrazone (H2LPB), and its six rare earth (La, Pr, Nd, Sm, Gd and Er) complexes are reported. The composition and the properties of the complexes were characterized by element analysis, thermal analysis, UV, IR and H NMR spectra. Besides, relaxivity (R1) of Gd-complex has been determined by INVREC.Au program, using inversion recovery pulse sequences, R1=8.05 mmol ·L-1 · s-1. The acute toxicity of Gd-complex in animal has also been tested, and the median lethal dose (LD50) is equal to (468.2±30) mg/kg.
文摘Five DTPA bis(amide)s have been synthesized and characterized by means of 1 H NMR , FT IR and elemental analyses. The stability constants of their Gd 3+ complexes have been measured using a simple spectrophotometric method. The results show that the complexing properties of the ligands in comparison with those of DTPA are affected by converting two carboxyl groups to amide groups. The relaxation studies have shown that the relaxivity of the chelates is similar to that of Gd DTPA, indicating that in solution all the chelates have one water molecule directly coordinated to the metal ion. Only one water molecule in inner coordination sphere suggests the coordination of the carboxamide oxygen to gadolinium ion, which agrees with the FT IR results.
基金financial support from National Natural Science Foundation of China(No.21971045)National Key Technologies R&D Program of China(No.2017YFA0205103)。
文摘It is greatly desired to develop novel gadolinium-based contrast agents(GBCAs)as improved platforms for magnetic resonance imaging(MRI).Herein,we report the syntheses of a series of nonionic cyclenbased GBCAs by precisely tuning carboxylate group on DO3A-pyridine scaffold.[Gd-DO3A-4cp]is isolated which adopts an octadentate coordination mode with a free carboxylate group at 4-position of pyridine.It shows the r_(1)relaxivity of 5.8(mmol/L)^(-1)s^(-1)(3 T,25℃),which is 75%higher than 3.3(mmol/L)^(-1)s^(-1)of the clinic used[Gd-DOTA].The possible mechanisms behind the enhanced relaxivity are investigated and proposed by structure-property relationship studies.After validation of low cytotoxicity and considerable kinetic inertness,in-vivo studies are further examined,demonstrating its good MRI performance,biodistribution as well as the way of excretion.
文摘DTPA was covalently conjugated to the copolymer of L lysine and L tyrosine, then transchelated with Gd EDTA,the resultant polymer chelates were further reacted with 6 O bromoacetyl D galactose or methyl lactobionyloxyacetate to give PLT(Gd DTPA) with galactose moiety as liver targeting group.These macromolecular MRI contrast agents were characterized by means of FT IR, ICP AES, elementary analyses and UV Vis spectrophotometry. Their in vitro relaxivity and liver targeting property in mice were also investigated.
