Ca-montmorillonite samples from Choushan treated at various acid concentrations were studied using chemical analysis, XRD, 29Si and 27A1 MAS NMR, to investigate the microstructure of the activated montmorillonites. Wi...Ca-montmorillonite samples from Choushan treated at various acid concentrations were studied using chemical analysis, XRD, 29Si and 27A1 MAS NMR, to investigate the microstructure of the activated montmorillonites. With the increase of acid concentration and dissolution of cations of montmorillonite, the intensity of d(001) decreased obviously and significant changes of the microstructure of Si and Al occurred. There were two new types of structural units of Si atoms formed: (SiO)3SiOH units and Q4(0A1) units. For Al atoms, in the course of activation, the removal of one of a pair of octahedral aluminium atoms from montmorillonite removed two hydroxyl groups and left the other aluminum of the pair in the four-fold coordination. The 27A1 signal at 5 54.0 corresponding to AlIV arose from the four-coordinated Al in the octahedral sheet. This study first confirmed, by 29Si and 27A1 MAS NMR spectra, that the model of microstructural evolution for activated montmorillonite postulated by Thomas et al. (1950)展开更多
[AlO4Al12(OH)24(H2O)12]7+ (Al13) formation in electrolysis process is studied. The results detected by27Al NMR spectroscopy show that high content of Al13 polymer is formed in the partially hydrolyzed aluminum solutio...[AlO4Al12(OH)24(H2O)12]7+ (Al13) formation in electrolysis process is studied. The results detected by27Al NMR spectroscopy show that high content of Al13 polymer is formed in the partially hydrolyzed aluminum solution prepared by controlled electrolysis process. In the produced electrolyte of total Al concentration ([AlT]) 2.0 mol · L?1 with a basicity (B = OH/Al molar ratios) of 2.0, the content of Al13 polymer is over 60% of total Al. Dynamic light scattering shows that the size distribution of the final electrolyte solutions ([AlT] = 2.0 mol · L?1) is trimodal with B = 2.0 and bimodal with B = 2.5. The aggregates of Al13 complexes increase the particle size of partially hydrolyzed aluminum solution.展开更多
Background Renal hypertrophy has been regarded as the early feature of diabetic nephropathy （DN）, which may eventually lead to proteinuria and renal fibrosis. However, the exact mechanism of renal hypertrophy is sti...Background Renal hypertrophy has been regarded as the early feature of diabetic nephropathy （DN）, which may eventually lead to proteinuria and renal fibrosis. However, the exact mechanism of renal hypertrophy is still unclear. The aim of this study was to investigate the possible association of connective tissue growth factor （CTGF） with renal hypertrophy in uninephrectomized diabetic rats. Methods Seventy-two Sprague-Dawley （SD） rats were randomly divided into two groups： control group （group C, n=32） and diabetic nephropathy （group DN, n=40）. Each group was re-divided into 4 subgroups according to the experimental period. The rats were sacrificed at 1, 2, 4, and 8 weeks respectively after induction of diabetes. Diabetes was induced by intraperitoneal injection of streptozotocin （STZ） after rats had received uninephrectomy. Blood glucose （BG）, body weight （BW）, 24-h urinary albumin excretion （24hUalb）, kidney weight （KW）, KW/BW, glomerular tuft area （AG）, glomerular tuft volume （VG）, proximal tubular area （AT） at each time point, the width of glomerular basement membrane （GBM） and tubular basement membrane （TBM） at week 8 were measured when the rats were sacrificed. Renal expression of CTGF and p27kipl were detected by immnnohistochemical staining. The relationship between CTGF expression and increasing of VG and AT was analyzed. Results There was a significant increase of 24hUalb, KW, and KW/BW from week 1 onward in diabetic rats compared to those in group C （P〈0.05, respectively）, diabetic rats also had a significant increase of AG, VG, and AT from week 1 onward. It was also shown that diabetic rats had a thickening of GBM [（245.7±103.0） nm vs （121.8±19.1） nm, P〈0.01] and TBM [（767.7±331.1） nm vs （293.0±110.5） nm, P〈0.01] at week 8. There was a weak expression for CTGF and p27kipl in normal glomeruli and tubuli, while a significant increasing expression of CTGF and p27kipl was found in glomeruli and tubuli in diabetic k展开更多
基金This wok was supported by the National Natural Science Foundation of China (Grant No. 49972018)the Natural Science Foundation of Guangdong Province (Grant No. 990522).
文摘Ca-montmorillonite samples from Choushan treated at various acid concentrations were studied using chemical analysis, XRD, 29Si and 27A1 MAS NMR, to investigate the microstructure of the activated montmorillonites. With the increase of acid concentration and dissolution of cations of montmorillonite, the intensity of d(001) decreased obviously and significant changes of the microstructure of Si and Al occurred. There were two new types of structural units of Si atoms formed: (SiO)3SiOH units and Q4(0A1) units. For Al atoms, in the course of activation, the removal of one of a pair of octahedral aluminium atoms from montmorillonite removed two hydroxyl groups and left the other aluminum of the pair in the four-fold coordination. The 27A1 signal at 5 54.0 corresponding to AlIV arose from the four-coordinated Al in the octahedral sheet. This study first confirmed, by 29Si and 27A1 MAS NMR spectra, that the model of microstructural evolution for activated montmorillonite postulated by Thomas et al. (1950)
基金This work was supported by the National Natural Science Foundation of China (Grant No. 50108016).
文摘[AlO4Al12(OH)24(H2O)12]7+ (Al13) formation in electrolysis process is studied. The results detected by27Al NMR spectroscopy show that high content of Al13 polymer is formed in the partially hydrolyzed aluminum solution prepared by controlled electrolysis process. In the produced electrolyte of total Al concentration ([AlT]) 2.0 mol · L?1 with a basicity (B = OH/Al molar ratios) of 2.0, the content of Al13 polymer is over 60% of total Al. Dynamic light scattering shows that the size distribution of the final electrolyte solutions ([AlT] = 2.0 mol · L?1) is trimodal with B = 2.0 and bimodal with B = 2.5. The aggregates of Al13 complexes increase the particle size of partially hydrolyzed aluminum solution.
基金This research is supported by the National Natural Science Fundation (No. 30471732), Jiangsu Provincial Natural Science Fundation (No. 2002052), and the Jiangsu Key Medical Talent Project (No. 2002072).
文摘Background Renal hypertrophy has been regarded as the early feature of diabetic nephropathy （DN）, which may eventually lead to proteinuria and renal fibrosis. However, the exact mechanism of renal hypertrophy is still unclear. The aim of this study was to investigate the possible association of connective tissue growth factor （CTGF） with renal hypertrophy in uninephrectomized diabetic rats. Methods Seventy-two Sprague-Dawley （SD） rats were randomly divided into two groups： control group （group C, n=32） and diabetic nephropathy （group DN, n=40）. Each group was re-divided into 4 subgroups according to the experimental period. The rats were sacrificed at 1, 2, 4, and 8 weeks respectively after induction of diabetes. Diabetes was induced by intraperitoneal injection of streptozotocin （STZ） after rats had received uninephrectomy. Blood glucose （BG）, body weight （BW）, 24-h urinary albumin excretion （24hUalb）, kidney weight （KW）, KW/BW, glomerular tuft area （AG）, glomerular tuft volume （VG）, proximal tubular area （AT） at each time point, the width of glomerular basement membrane （GBM） and tubular basement membrane （TBM） at week 8 were measured when the rats were sacrificed. Renal expression of CTGF and p27kipl were detected by immnnohistochemical staining. The relationship between CTGF expression and increasing of VG and AT was analyzed. Results There was a significant increase of 24hUalb, KW, and KW/BW from week 1 onward in diabetic rats compared to those in group C （P〈0.05, respectively）, diabetic rats also had a significant increase of AG, VG, and AT from week 1 onward. It was also shown that diabetic rats had a thickening of GBM [（245.7±103.0） nm vs （121.8±19.1） nm, P〈0.01] and TBM [（767.7±331.1） nm vs （293.0±110.5） nm, P〈0.01] at week 8. There was a weak expression for CTGF and p27kipl in normal glomeruli and tubuli, while a significant increasing expression of CTGF and p27kipl was found in glomeruli and tubuli in diabetic k
