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A letter to the editor is presented about a case study on immune reconstitution syndrome, published in the January 2007 issue.

Selective catalytic reduction of NO x in the presence of alkali (earth) metals and heavy metals is still a challenge due to the easy deactivation of catalysts. Herein, NO x reduction over smart catalysts with self-created targeted antipoisoning sites is originally demonstrated. The smart catalyst consisted of TiO 2 pillared montmorillonite with abundant cation exchange sites to anchor poisoning substances and active components to catalyze NO x into N 2 . It was not deactivated during the NO x reduction process in the presence of alkali (earth) metals and heavy metals. The enhanced surface acidity, reducible active species, and active chemisorbed oxygen species of the smart catalyst accounted for the remarkable NO x reduction efficiency. More importantly, the self-created targeted antipoisoning sites expressed specific anchoring effects on poisoning substances and protected the active components from poisoning. It was demonstrated that the tetrahedrally coordinated aluminum species of the smart catalyst mainly acted as self-created targeted antipoisoning sites to stabilize the poisoning substances into the interlayers of montmorillonite. This work paves a new way for efficient reduction of NO x from the complex flue gas in practical applications.

Nowadays, the serious deactivation of deNO x catalysts caused by alkali metal poisoning was still a huge bottleneck in the practical application of selective catalytic reduction of NO x with NH 3 . Herein, alkali-resistant NO x catalytic reduction over metal oxide catalysts using Ti-modified attapulgite (ATP) as supports has been originally demonstrated. The self-defense effects of Ti-modified ATP for alkali-resistant NO x catalytic reduction have been clarified. Ti-modified ATP with self-defense ability was obtained by removing alkaline metal cation impurities in the natural ATP materials without destroying its initial layered-chain structure through the ion-exchange procedure, accompanied with an obvious enrichment of Brønsted acid and Lewis acid sites. The self-defense effects embodied that both ion-exchanged Ti octahedral centers and abundant Si-OH sites in the Ti-ion-exchange-modified ATP could effectively anchor alkali metals via coordinate bonding or ion-exchange process, which induced alkali metals to be immobilized by the Ti-ion-exchange-modified ATP carrier rather than impair active species. Under this special protection of self-defense effects, Ti-ion-exchange-modified ATP supported catalysts still retained plentiful acidic sites and superior redox ability even after alkali metal poisoning, giving rise to the maintenance of sufficient NH x and NO x adsorption and the subsequent efficient reaction, which in turn resulted in high NO x catalytic reduction capacity of the catalyst. The strategy provided new inspiration for the development of novel and efficient selective catalytic reduction of NO x with NH 3 (NH 3 -SCR) catalysts with high alkali resistance.

The significance of interethnic variation in CD4 counts between Asian and Caucasian populations is not known. Patients on combination antiretroviral therapy from Treat Asia and Australian HIV Observational Databases (TAHOD, predominantly Asian, n = 3356; and AHOD, predominantly Caucasian, n = 2312, respectively) were followed for 23 144 person-years for AIDS/death and all-cause mortality endpoints. We calculated incidence-rates and used adjusted Cox regression to test for the interaction between cohort (TAHOD/AHOD) and time-updated CD4 count category (lagged by 3 months) for each of the endpoints. There were 382 AIDS/death events in TAHOD (rate: 4.06, 95%CI: 3.68-4.50) and 305 in AHOD (rate: 2.39, 95%CI: 2.13-2.67), per 100 person-years. At any given CD4 count category, the incidence-rates of endpoints were found to be similar between TAHOD and AHOD (in the adjusted models, P > .05 for the interaction term between cohort type and latest CD4 counts). At any given CD4 count, risk of AIDS or death was not found to vary by ethnicity, suggesting that the CD4 count thresholds for predicting outcomes defined in Caucasian populations may be equally valid in Asian populations.

Background: Random effects models were used to explore how the shape of CD4 cell count responses after commencing combination antiretroviral therapy (cART) develop over time and, in particular, the role of baseline and follow-up covariates., Methods: Patients in Asia Pacific HIV Observational Database who first commenced cART after January 1, 1997, and who had a baseline CD4 cell count and viral load measure and at least 1 follow-up measure between 6 and 24 months, were included. CD4 cell counts were determined at every 6-month period after the commencement of cART for up to 6 years., Results: A total of 1638 patients fulfilled the inclusion criteria with a median follow-up time of 58 months. Lower post-cART mean CD4 cell counts were found to be associated with increasing age (P < 0.001), pre-cART hepatitis C coinfection (P = 0.038), prior AIDS (P = 0.019), baseline viral load < or equal to 100,000 copies per milliliter (P < 0.001), and the Asia Pacific region compared with Australia (P = 0.005). A highly significant 3-way interaction between the effects of time, baseline CD4 cell count, and post-cART viral burden (P < 0.0001) was demonstrated. Higher long-term mean CD4 cell counts were associated with lower baseline CD4 cell count and consistently undetectable viral loads. Among patients with consistently detectable viral load, CD4 cell counts seemed to converge for all baseline CD4 levels., Conclusions: Our analysis suggest that the long-term shape of post-cART CD4 cell count changes depends only on a 3-way interaction between baseline CD4 cell count, viral load response, and time.