The influence of low-level viremia on CD4+ cell count in human immunodeficiency virus-infected patients.

BACKGROUND: Following initiation of combined antiretroviral therapy, the majority of human immunodeficiency virus-infected patients experience immune reconstitution indicated by virologic suppression and an increase in peripheral CD4+ T-cell counts. Some patients may suffer from low-level viremia, which was reported to be significantly associated with acquired immunodeficiency syndrome cases, virologic failure, and death. We aimed to further investigate the influence of low-level viremia on CD4+ T-cell count. METHODS: In our study, we included human immunodeficiency virus-seropositive patients on combined antiretroviral therapy, for at least 6 months, who received at least one assessment of human immunodeficiency virus plasma viral load and CD4+ cell count every 6 months, from January 2009 to January 2019. The copy-year viremia was determined by calculating the area under the curve of the plasma human immunodeficiency virus viral load. RESULTS: When comparing patients with a mean CD4+ cell count <200 cells/µL, there was no significant difference between patients with a mean viral load <1000 copies/mL and patients with a mean viral load ≥1000 copies/mL (p = 0.219). Among those with a mean viral load <1000 copies/mL, a higher proportion of patients had a mean CD4+ cell count ≥500 cells/µL (p < 0.001). The mean CD4+ cell count of patients with copy-years viremia (log10) <4 (577.7, interquartile range 429.2-736.7) was significantly higher than that of patients with copy-years viremia (log10) ≥4 (443.3, interquartile range 319.0-558.4) (p < 0.001). In multivariate logistic regression analysis, we observed that malignancy without history, lower copy-years viremia, and high nadir CD4+ cell count were independent predictors of mean CD4+ cell count ≥500 cells/µL. CONCLUSION: Human immunodeficiency virus-infected patients with a history of malignancy, high copy-year viremia, and lower nadir CD4+ cell counts should be monitored carefully in clinical settings.

Catalytic decomposition of hydrogen peroxide and 4-chlorophenol in the presence of modified activated carbons.

The objective of this research was to examine the heterogeneous catalytic decomposition of H(2)O(2) and 4-chlorophenol (4-CP) in the presence of activated carbons modified with chemical pretreatments. The decomposition of H(2)O(2) was suppressed significantly by the change of surface properties including the decreased pH(pzc) modified with oxidizing agent and the reduced active sites occupied by the adsorption of 4-CP. The apparent reaction rate of H(2)O(2) decomposition was dominated by the intrinsic reaction rates on the surface of activated carbon rather than the mass transfer rate of H(2)O(2) to the solid surface. By the detection of chloride ion in suspension, the reduction of 4-CP was not only attributed to the advanced adsorption but also the degradation of 4-CP. The catalytic activity toward 4-CP for the activated carbon followed the inverse sequence of the activity toward H(2)O(2), suggesting that acidic surface functional group could retard the H(2)O(2) loss and reduce the effect of surface scavenging resulting in the increase of the 4-CP degradation efficiency. Few effective radicals were expected to react with 4-CP for the strong effect of surface scavenging, which could explain why the degradation rate of 4-CP observed in this study was so slow and the dechlorination efficiency was independent of the 4-CP concentration in aqueous phase. Results show that the combination of H(2)O(2) and granular activated carbon (GAC) did increase the total removal of 4-CP than that by single GAC adsorption.

Influence of surface modification on catalytic activity of activated carbon toward decomposition of hydrogen peroxide and 2-chlorophenol.

The objective of this research was to investigate the influence of the activated carbons modified by chemical treatment on the surface catalyzed loss of H2O2 and 2-CP. The characteristics of the modified activated carbons were examined by several techniques including nitrogen adsorption, SEM, and EDS. The H2O2 decomposition rate would be suppressed significantly either by the change of surface properties modified with chemical treatment or the reduction of active sites occupied with the adsorption of 2-CP. In addition, the H2O2 decomposition rate with activated carbons within a specific time can be described by a second-order kinetic expression with respect to the concentration of GAC and H2O2 in the absence or presence of 2-CP. The catalytic activities of the three activated carbons toward 2-CP reduction followed the inverse sequence of those toward H2O2 loss, implying that acidic surface functional group could retard the H2O2 loss and reduce the effect of surface scavenging resulting in increasing the reduction efficiency of 2-CP. By the detection of chloride ions in reaction mixture, it can be demonstrated that the reduction of 2-CP was not only attributed to the advanced adsorption but also the oxidation of the 2-CP with effective radicals. The real oxidation efficiency of 2-CP for the activated carbon modified with hot nitric acid was observed between 0.04 and 0.01 (mol/mol), offering a comparable efficiency to that of the other oxidation system using metal oxide as catalyst.