One concern is to what extent the subset of NHANES participants evaluated for HCV infection and diabetes was representative of the entire NHANES population sample. This is a significant question because the overall NHANES sample is considered the best representation of the general population of the United States, a collection of subjects free of the bias usually present in clinic-based investigations. Thus, it was reassuring that the subset of NHANES that could be evaluated for HCV infection and diabetes was both large (9,841 persons) and similar to other NHANES members with respect to many factors, including all recognized correlates of both HCV infection and diabetes. 1 This representation essentially eliminates the potential for selection bias. Another strength of the NHANES analysis is the careful testing for HCV infection performed by the Hepatitis Branch at the Centers for Disease Control and Prevention. Because HCV infection was assessed by second-generation enzyme immunoassay and confirmed by supplemental antibody testing, there is no doubt that most positive results reflect true HCV exposure. Indeed, in the subset tested for both HCV antibody and RNA, HCV RNA was detected in all but 26%, the percent one would expect to have cleared infection if all antibody-positive subjects had been previously infected. 3 Dr. Everhart raised the question of whether the antibody testing should be the main determinant of HCV or if the analysis should be restricted to persons with both HCV antibody and RNA. 2 If one were convinced that the association exists exclusively because ongoing HCV infection caused diabetes, it would have been appropriate to restrict the analysis to persons whose blood contained both HCV antibodies and RNA. Because too little is known about the pathogenesis and temporal sequence of HCV infection and diabetes to make these assumptions, the analysis initially was presented using antibody testing as the marker of HCV exposure. Nonetheless, Dr. Nainan and coworkers at the Centers for Disease Control and Prevention generously provided the HCV RNA data. For the subset for whom there is HCV RNA testing, the age-adjusted odds of type 2 diabetes in persons with HCV RNA and antibody was 2.48 (95% CI 1.23-5.01) compared with 0.98 for persons with HCV antibody but not RNA. If confirmed , these data are not consistent with the conjecture that diabetes leads to HCV infection, but instead favor hypotheses suggesting that persistent HCV infection is associated with the subsequent development of diabetes. Another important discovery in the analysis of HCV infection and type 2 diabetes in NHANES was the difference in the magnitude and direction of the association in persons of relatively young ages. Type 2 diabetes is a clinically heterogeneous syndrome that, according to the Cecil Textbook of Medicine, "typically appears after the age of 40 years." 4 In NHANES III, type 2 diabetes was not associated with HCV infection in persons less than 40 years of age. 1 Type 2 diabetes may be a different condition when it mani...

No abstract

No abstract

Radial uniformity measurements of plasma density were carried out by using a floating double probe in a cylindrical (21 cm in electrode diameter) capacitive discharge reactor driven over a wide range of frequencies (27–220 MHz). At low rf power, a multiple-node structure of standing wave effect was observed at 130 MHz. The secondary density peak caused by the standing wave effect became pronounced and shifts toward the axis as the driving frequency further to increase, indicative of a much more shortened standing-wave wavelength. With increasing rf power, the secondary density peak shift toward the radial edge, namely, the standing-wave wavelength was increased, in good qualitative agreement with the previous theory and simulation results. At higher pressures and high frequencies, the rf power was primarily deposited at the periphery of the electrode, due to the fact that the waves were strongly damped as they propagated from the discharge edge into the center.

No abstract

The object of this study was to evaluate the effect of sewage sludge biochar on adsorption and mobility of Cr, Mn, Cu, and Zn. Biochar (BC400) was produced via pyrolysis of municipal sewage sludge at 400 °C. Maximum adsorption capacities (qm) for Zn, Cr, Mn, and Cu were 5.905, 5.724, 5.681, and 5.342 mg·g−1, respectively, in the mono-metal solution and 2.475, 8.204, 1.01, and 5.415 mg·g−1, respectively, in the multi-metal solution. The adsorption capacities for Mn, Cu, and Zn decreased in the multi-metal solution due to competitive adsorption, whereas the capacity for Cr increased. Surface precipitation is an important mechanism in the sorption of these metals on BC400. The 360-day incubation experiment showed that BC400 application reduced metal mobility in contaminated soils, which was attributed to the substantial decreases in the acid-soluble fractions of Cr, Mn, Cu, and Zn (72.20%, 70.38%, 50.43%, and 29.78%, respectively). Furthermore, the leaching experiment using simulated acid rain indicated that the addition of BC400 enhanced the acid buffer capacity of contaminated soil, and the concentration of Cr, Mn, Cu, and Zn in the leachate was lower than in untreated soil. Overall, this study indicates that sewage sludge biochar application reduces the mobility of heavy metal in co-contaminated soil, and this adsorption experiment is suitable for the evaluation of biochar properties for remediation.

This study determined whether selective transmission of hepatitis C virus (HCV) species occurred among human and chimpanzee recipients of contaminated blood products or plasma containing multiple genotypes, subgenotypes and quasispecies. Commercially prepared factor VIII concentrate (lot DO56), produced prior to HCV testing and inactivation, was subsequently found by direct cloning to contain the following subgenotypes: 1a and 1b (73 % of clones), 2a (13 % of clones), 2b (11 % of clones) and 3a (4 % of clones). A patient transfused with factor VIII concentrate DO56 was diagnosed with clinical non-A, non-B hepatitis and subsequently found to be infected with HCV subgenotype 1b. Among five chimpanzees inoculated experimentally with the same factor VIII concentrate, two were infected only with HCV subgenotype 1a and three were infected with approximately equivalent clonal proportions of subgenotypes 1a and 1b. HCV hypervariable region 1 (HVR1) quasispecies analysis of the DO56 factor VIII concentrate and a serum specimen from the single chimpanzee that developed a chronic HCV infection following inoculation with DO56 showed 0-56 % nucleotide variation. However, specimens from chimpanzees infected in the second to fourth passages of the DO56 inoculum had 0-8 % HVR1 quasispecies nucleotide variation. The high HVR1 quasispecies variation in the factor VIII concentrate and its first passage in chimpanzees indicates the presence of multiple HCV isolates, whereas the low variation in the second to fourth chimpanzee passages suggests transmission of a single HCV isolate. These findings strongly suggest selective transmission of HCV isolates during experimental chimpanzee infection and among humans exposed to multiple HCV species. INTRODUCTIONHepatitis C virus (HCV) infection is a major cause of chronic liver disease worldwide (Choo et al., 1989;Alter & Seeff, 2000). Infection is transmitted primarily by parenteral exposure to blood or blood products that have not undergone screening or viral inactivation, or by exposure to blood from shared needles and syringes during injection drug use or unsafe medical procedures (Alter, 1997).Six major HCV genotypes and several subgenotypes have been identified (Simmonds et al., 1993;de Lamballerie et al., 1997). In addition, HCV displays a high rate of nucleotide substitutions in the hypervariable region 1 (HVR1) of the envelope gene and exists as a number of distinct quasispecies (Pawlotsky, 1998). Analysis of the genetic relatedness of HVR1 among infected persons has been used to track transmission of HCV infections (Gretch et al., 1996;Ni et al., 1997; Ross et al., 2000;Cody et al., 2002).Both superinfections and mixed infections have been observed in patients with chronic hepatitis C (Kao et al., 1993(Kao et al., , 1994 Widell et al., 1995;Giannini et al., 1999;Herring et al., 2004). In addition, persons can be infected with several genotypes or subgenotypes of HCV following exposure to blood or blood products (Qian et al., 2000;Bowden et al., 2005). Possible explanations for mi...

A hybrid model, i.e. a global model coupled bidirectionally with a parallel Monte-Carlo collision (MCC) sheath model, is developed to investigate an inductively coupled discharge with a bias source. This hybrid model can self-consistently reveal the interaction between the bulk plasma and the radio frequency (rf) bias sheath. More specifically, the plasma parameters affecting characteristics of rf bias sheath (sheath length and self-bias) are calculated by a global model and the effect of the rf bias sheath on the bulk plasma is determined by the voltage drop of the rf bias sheath. Moreover, specific numbers of ions are tracked in the rf bias sheath and ultimately the ion energy distribution function (IEDF) incident on the bias electrode is obtained. To validate this model, both bulk plasma density and IEDF on the bias electrode in an argon discharge are compared with experimental measurements, and a good agreement is obtained. The advantage of this model is that it can quickly calculate the bulk plasma density and IEDF on the bias electrode, which are of practical interest in industrial plasma processing, and the model could be easily extended to serve for industrial gases.