One step fabrication of aligned carbon nanotubes using gas rectifier.

We report the one-step fabrication of aligned and high-quality carbon nanotubes (CNTs) using floating-catalyst chemical vapor deposition (FCCVD) with controlled fluidic properties assisted by a gas rectifier. The gas rectifier consists of one-dimensional straight channels for regulating the Reynolds number of the reaction gas. Our computational fluid dynamics simulation reveals that the narrow channels of the gas rectifier provide steady and accelerated laminar flow of the reaction gas. In addition, strong shear stress is induced near the side wall of the channels, resulting in the spontaneous formation of macroscopic CNT bundles aligned along the direction of the gas flow. After a wet-process using chlorosulfonic acid, the inter-tube voids inherently observed in as-grown CNT bundles are reduced from 16 to 0.3%. The resulting CNT fiber exhibits a tensile strength of 2.1 ± 0.1 N tex-1 with a Young's modulus of 39 ± 4 N tex-1 and an elongation of 6.3 ± 0.6%. FCCVD coupled with the strong shear stress of the reaction gas is an important pre-processing route for the fabrication of high-performance CNT fibers.

Epstein-Barr virus DNA load and seroconversion in pediatric renal transplantation with tacrolimus immunosuppression.

EBV infection is one of major complications arising in pediatric patients who have undergone renal transplantation. A strong correlation between the grade of immunosuppression and the development of PTLD, one of the most severe EBV-associated diseases, has been recognized. In this study, we monitored the serologic profile in conjunction with peripheral blood EBV-DNA load of 32 children who underwent renal transplantation with tacrolimus as an immunosuppressant. Six patients were EBV-seronegative (EBV-) before the transplantation, and the mean DNA load in the EBV- group was significantly higher than that in the EBV-seropositive (EBV+) group. Seroconversion occurred in five of these patients in a mean period of 22 weeks after the transplantation. The EBV-DNA load in the EBV+ group was maintained at a low level for a year, whereas it increased rapidly to over 1 x 10(5) copies/mL in two patients in the EBV- group three to seven months after the transplantation, which corresponds to the timing of seroconversion, and one of them developed PTLD. These observations suggest that the close monitoring of the EBV-DNA load, along with longitudinal observation of seroconversion, is essential in pediatric renal transplantation, particularly for younger children who are more likely to be EVB-.

The sialoadhesin (CD169) expressing a macrophage subset in human proliferative glomerulonephritis.

BACKGROUND: Sialoadhesin (Sn; CD169) is a lectin-like receptor whose expression is restricted to subsets of tissue and inflammatory macrophages. We have previously identified accumulation of Sn+ macrophages as an important marker of disease progression versus remission in rat mesangial proliferative nephritis. The current study examined the significance of Sn+ macrophages in human proliferative glomerulonephritis. METHODS: Frozen kidney sections from normal adult human kidney (n = 4) and pediatric nephropathy (n = 40) were stained for total macrophages (CD68+ cells), Sn+ macrophages, CD3+ T-cells and collagen type I by immunofluorescence. Leukocyte infiltration and the severity of glomerular lesions and interstitial damage were scored. A second protocol biopsy was performed in 27 cases and clinical and biopsy-based data obtained. RESULTS: Sn+ macrophages were absent from glomeruli in normal adult human kidney and in thin basement membrane disease (n = 4), but were detected in 4 of 9 cases of purpura nephritis; 7 of 17 IgA nephropathy; 5 of 5 membranoproliferative glomerulonephritis, and 5 of 5 lupus nephritis. Sn+ macrophages were localized in areas of focal glomerular and interstitial damage. Two-colour immunostaining confirmed that Sn+ cells are a subset of total CD68+ macrophages. The number of glomerular Sn+ macrophages correlated with the degree of proteinuria and glomerular lesions (r = 0.44, P = 0.0045 and r = 0.82, P<0.0001; respectively), while interstitial Sn+ macrophages correlated with the degree of proteinuria and interstitial damage (r = 0.59, P<0.0001 and r = 0.75, P<0.0001; respectively). Combined immunostaining revealed that interstitial Sn+ macrophages and CD3+ T-cells co-localized in areas of tubulointerstitial damage with increased type I collagen deposition. There was significant correlation between the number of interstitial Sn+ macrophages and CD3+ T-cells (r = 0.74, P<0.0001). Most patients responded to a 2 year period of glucocorticoid therapy with a reduction in proteinuria and glomerular lesions and this correlated with the reduction in the number of glomerular Sn+ macrophages. CONCLUSION: This study has identified Sn+ cells as a macrophage subset whose accumulation in the kidney correlates with proteinuria and histologic damage. These results, together with recent findings from animal studies, suggest that Sn+ macrophages may play an important role in progressive renal disease.