In patients with chronic hepatitis C, a regimen of peginterferon alfa-2a given once weekly is more effective than a regimen of interferon alfa-2a given three times weekly.

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Previous studies in Caucasian patients showed treatment of chronic hepatitis C with pegylated interferon/ribavirin was well tolerated, and produced a higher response rate especially in genotype 1 infections. However, it is unknown whether this conclusion can be extrapolated to patients with Chinese ethnic origin. A total of 153 patients with biopsy-proven chronic hepatitis C were randomly assigned to receive either weekly injection of peginterferon alpha-2b 1.5 mcg/kg plus oral ribavirin (1000 or 1200 mg/day, depending on body weight) (PEG group, n = 76) or 3 MU of interferon alpha-2b t.i.w. plus ribavirin (IFN group, n = 77) for 24 weeks. Sustained virological response (SVR) was defined as the sustained disappearance of serum hepatitis C virus (HCV) RNA at 24 weeks after the end of treatment by polymerase chain reaction assay. Baseline demographic, viral and histological characteristics were comparable between the two groups. Using an intent-to-treat analysis, HCV genotype 1 patients showed a significantly higher SVR in patients receiving PEG-IFN rather than IFN (65.8%vs 41.0%, P = 0.019), but no difference was found in genotype non-1 patients (PEG vs IFN: 68.4%vs 86.8%, P = 0.060). Genotype 1 patients (28.6%) in the PEG-IFN group relapsed, as compared with 52.9% in the IFN group (P = 0.040). Multivariate analyses showed early virological response at week 12 of therapy and genotype non-1 were significant predictors to SVR. As compared with the IFN group, patients receiving PEG-IFN had a significantly higher rate of discontinuation, dose reduction, fever, headache, insomnia, leucopenia and thrombocytopenia. In genotype 1 chronic hepatitis C Chinese patient, PEG-IFNalpha2b ribavirin had significantly better SVR and lower relapse rate when compared to IFN/ribavirin. Both regimens can be recommended for genotype non-1 chronic hepatitis C Chinese patients. However, a higher rate of adverse events and discontinuance of therapy were noted in patients treated with PEG-IFNalpha2b ribavirin.

Serum HBsAg concentration might serve as a surrogate marker of HBV DNA level in CHB patients.

Compared with lamivudine therapy with detectable serum HBV RNA in patients with chronic HBV infection, interferon treatment might reduce HBV DNA replication through the inhibition of HBV RNA replicative intermediates, resulting in the loss of serum HBV RNA.

Two dimensional magic clusters have been directly observed on the p 3 3p 3 R30 ± reconstructed Ga͞Si(111) surface using scanning tunneling microscopy. The magic numbers are n͑n 1 1͒͞2, where n (2, 3, 4, or 5) is the number of atoms on each side of these triangular clusters with preferred orientation with respect to the substrate. The p 3 3p 3 R30 ± adatom lattice surrounding the magic clusters exhibits characteristic vacancies. A structural model is proposed to account for the cluster orientation and lattice vacancies as well as the extraordinary abundance and stability of the decamers ͑n 4͒. [S0031-9007(98)06520-X] PACS numbers: 68.35.Bs, 61.16.ChMagic clusters, i.e., clusters with enhanced stability at certain sizes, have been intensively studied over the last decade. For magic clusters in free space, many interesting results about their electronic and atomic shell structures are found in the literature [1][2][3][4][5][6]. In contrast, magic clusters supported by a substrate (henceforth referred to as 2D magic clusters) are rarely discussed. Only recently have researchers found indirect evidence of such clusters in a molecular beam scattering experiment [7] and issues related to the stability of clusters on various substrates caught researchers' attention [8,9]. The main difference between free and supported clusters lies in the presence of the supporting substrate for the latter. The geometric constraint and electronic effect exerted by the substrate may or may not destroy the stability of an approaching magic cluster. For example, according to a calculation [8], Na 8 (a magic cluster in free space) retains its intrinsic structure after landing on the insulating NaCl(100) surface, but it spontaneously collapses on the Na(110) surface. Therefore, it is of fundamental interest to search for direct evidence of 2D magic clusters and study the cluster-surroundings interaction that needs not to be considered for magic clusters in free space. The recent interests in 2D magic clusters are also related to emerging attempts to coat surfaces with size-selected clusters [10]. Since the formation of 2D magic clusters is a plausible approach to the creation of this type of novel material, it is important to experimentally demonstrate the existence of 2D magic clusters and understand the conditions and mechanism for their formation.

To exploit Rashba effect in a 2D electron gas on silicon surface for spin transport, it is necessary to have surface reconstruction with spin-split metallic surface-state bands. However, metals with strong spin-orbit coupling (e.g., Bi, Tl, Sb, Pt) induce reconstructions on silicon with almost exclusively spin-split insulating bands. We propose a strategy to create spin-split metallic bands using a dense 2D alloy layer containing a metal with strong spin-orbit coupling and another metal to modify the surface reconstruction. Here we report two examples, i.e., alloying reconstruction with Na and Tl/Si(111)1 × 1 reconstruction with Pb. The strategy provides a new paradigm for creating metallic surface state bands with various spin textures on silicon and therefore enhances the possibility to integrate fascinating and promising capabilities of spintronics with current semiconductor technology.