INTRODUCTIONThe hepatitis C virus (HCV) epidemic now affects over 200 million people worldwide. HCV is a single-stranded RNA flavivirus that is responsible for the majority of non-A-non-B hepatitis infections [1,2] . Natural history studies have found that 15%-59% of people who are infected with HCV will undergo spontaneous viral clearance with no further liver disease due to HCV [3][4][5][6][7][8][9][10][11] . The remaining will develop chronic HCV infection that can lead to cirrhosis, hepatocellular carcinoma and the need for a liver transplant.The exact mechanism of HCV RNA clearance is not well understood although recent studies have shown that clearance is associated with strong, broad cellular immune responses [12][13][14][15][16][17][18][19] . Other factors such as younger age [3,20] , female gender [21,22] , presence of hepatitis B surface antigen (HBsAg) [3,23] , certain HLA alleles [6,[24][25][26][27][28][29] , and low viral quasispecies diversity [30] have been linked to increased HCV RNA clearance. While African American ethnicity [3,25] , HCV genotype 1 [31][32][33] and co-infections with human immunodeficiency virus-1 (HIV-1) [3] , Human T-Lymphotropic Virus-1 [34] and Schistosoma mansoni [35] have been associated with lower HCV RNA clearance and higher HCV RNA levels. Understanding why and how individuals clear HCV is the key to developing new drugs and an effective vaccine [21] .Studies of heroin users from Guangxi Zhuang Autonomous Region in southern China have attributed the appearance and spread of HIV, HCV and other infectious agents to the change in heroin using patterns from smoking to injection [36] . Abstract AIM: To s t u d y t h e v i r o l o g i c a l a n d h o s t fa c t o r s influencing hepatitis C infection outcomes in heroin users in southern China. METHODS:HCV RNA and associated factors were analyzed among 347 heroin users from Guangxi Zhuang Autonomous Region, southern China who were hepatitis C virus (HCV) EIA positive for two or more consecutive visits. RESULTS:Using the COBAS AMPLICOR HCV TEST, a remarkably low HCV RNA negative rate of 8.6% was detected. After multivariate logistic regression analysis, HCV RNA clearance was significantly associated with the presence of HBsAg (OR = 8.436, P < 0.0001), the lack of HIV-1 infection (OR = 0.256, P = 0.038) and age younger than 25 (OR = 0.400, P = 0.029). CONCLUSION:Our study suggests HCV infection among Chinese heroin users results in high levels of viral persistence even amidst factors previously found to enhance viral clearance. Prospective studies of a possible genetic component within the Chinese population and the pathogenicity of non-genotype 1 HCV infections are needed. heroin trafficking routes into the province [37,38] . It is not clear how widespread the HCV epidemic is in China. Little seroprevalence data exists, mostly from the major cities of Beijing, Shanghai and Hong Kong and to our knowledge; no studies on HCV RNA clearance in China have been done. Studies in Yunnan Province, which borders Guangxi Zhuang Autonomous...
Al2O3coated polyhedral Fe nanocapsules were prepared by arc-discharging a Fe-Al(8at%Al) alloy. High-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy, and network analyzer were employed to investigate the microstructures, compositions and electromagnetic properties (2-18GHz). The reflection loss R(dB) of the nanocapsules reaches to -50.5dB at 7.9GHz with a 3mm thickness, and EM absorption properties(RL<-20dB) in the 5.2~16.1GHz range with thickness range of 1.67-4.7mm. The excellent Microwave-absorption properties of as-prepared nanocapsules are ascribed to shape anisotropy and core/shell structure.
BN coated Ni nanocapsules were prepared by arc evaporating Ni-B amorphous alloy powders synthesized by a mechanochemical reaction, and their microstructure, surface component as well as electromagnetic properties (2-18 GHz) were investigated by means of high-resolution transmission electron microscopy, X-ray diffraction , photoluminescence spectra (PL) and a network analyzer, respectively. The reflection loss R (dB) of the nanocapsules less than -20 dB was obtained in the frequency range of 4.3-18 GHz for an absorber thickness of 1.4-6 mm. An optimal reflection loss of -32.0 dB was reached at 13 GHz with an absorber thickness of 2 mm. The microwave absorptive mechanisms of BN-coated Ni nanocapsule absorbent were discussed.
-C-Fe-Si/SiC coated Fe nanocapsules were prepared by arc evaporating the mixture of Fe and SiC powders in He and H2 atmosphere, and their microstructure, surface compositions and electromagnetic(EM) properties(2–18GHz) were investigated by means of high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and network analyzer, respectively. The reflection loss R of less than –20 dB was obtained in the frequency range of 3.13–13.6 GHz with an absorber thickness of 2.0–5.5 mm. An optimal reflection loss of–37.2 dB was reached at 5.6GHz with an absorber thickness of 4.5mm. The microwave absorptive mechanisms of -C-Fe-Si/SiC coated Fe nanocapsules absorbent were discussed.
SiC coated Ni nanocapsules were prepared by arc evaporating the mixture of Ni and SiC powders in Ar and H2 atmosphere. HRTEM shows the as-prepared nanoparticles form in a core¬¬¬-shell structure, with the size of nanoparticles in range of 20-50nm and the thickness of the shell 2-6nm. X-Ray and X-ray photoelectron spectroscopy show core consist of Ni, while the shell consists of SiC. The core-shell structure can prevent Ni nanoparticles from oxidation and agglomeration. The electromagnetic characters were measured by Agilent 8722ES microwave network analyzer in the band of 2-18GHz. The reflection loss R(dB) of less than –20 dB was obtained in the frequency range of 3.8-11.1GHz with absorber thickness of 2.5–5mm, An optimal reflection loss of –33.4dB was reached at 7.4GHz with an absorber thickness of 3.5mm.In addition, the optimal RL obviously shifts to the lower-frequency range with increasing thickness of the layer.
A new type of antiferromagnetic CoAl2O4 coated ferromagnetic Co solid solution is synthesized by arc-discharging. Typical HRTEM images show that the nanocapsules form in a core-shell structure. The size of the nanocapsules is in range of 10-90 nm and the thickness of the shell is about 3-10 nm. X-ray photoelectron spectrum (XPS) and X-ray diffraction (XRD) reveal that the core consists of Co solid solution, while the shell is CoAl2O4. The magnetic field and temperature dependence of magnetizations confirm that the Co solid solution nanocapsules are basically in the ferromagnetic state below Curie temperature. In addition, the antiferromagnetic order occurs with Neél temperature TN of about 5 K. The saturation magnetization of Ms = 76.1 Am2/kg and the coercive force of Hc= 23.28 kA/m are achieved at room temperature for the Co solid solution nanocapsules.
B4C/C coated Co nanocapsules were prepared by arc-discharging a Co-B amorphous alloy. The structure, morphology and surface composition as well as magnetic properties were investigated by X-Ray diffraction, High Resolution Transmission Electron Microscopy and XPS photoelectron spectrum as well as Vibrating Sample Magnetometer, respectively. The results show the as-prepared nanoparticles form in a core¬¬¬-shell structure with the size of nanoparticles in range of 20-100nm, the thickness of the shell is about 3-10nm. The core is Co grains, while the shell is B4C/C compound. That B4C coated Co nanoparticles form in a core¬¬¬-shell structure ascribed to Co as catalysts accelerating reaction between B with C ionize in the arc-discharge course. This structure can prevent Co nanoparticles from oxidation and agglomeration. A saturation magnetization of Ms=75.6 Am2/kg and a coercive force of Hc=20.1 kA/m are achieved for as-prepared nanocapsules by VSM. For as–prepared nanocapsules, the saturation magnetization is reduced and coercive force of is enhanced while Comparing with Co block. The increase coercive force for as-prepared nanoparticles can be mainly ascribed to size of particles diminished and the domain-wall depinned in the multi-domain particles.
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