The properties of engineered nanomaterials and nanoparticles such as zinc oxide and titanium dioxide may differ substantially from naturally occurring materials and particles. Nanoparticles have unique physical properties making them ideal for use in various skin care products currently on the market. Nano-preparations are currently under investigation as novel treatments of acne vulgaris, recurrent condyloma accuminata, atopic dermatitis, hyperpigmented skin lesions, and other non-dermatologic diseases. Because of their increased surface area, nanoparticles have increased reactivity and a small size allowing for enhanced mobility through the human body and environment. As their use becomes more prevalent, nanoparticles are being scrutinized for their safety and long-term effects. This review discusses the benefits of nanoparticles in dermatological therapies and skin care products as well as potential disadvantages and possible mechanisms of toxicity.

Titanium dioxide nanoparticles (nano-TiO(2) ) are widely used in cosmetics, skin care products, paints, and water treatment processes. Disagreement remains regarding the safety of nano-TiO(2) , and little epidemiological data is available to provide needed resolution. Most studies have examined effects using acute exposure experiments with relatively few studies using a chronic exposure design. We examined cyto- and genotoxicity in CHO-K1 cells following 60 days of continuous exposure to defined levels of nano-TiO(2) (0, 10, 20, or 40 μg/ml). Oxidative stress increased in a concentration-dependent manner in short- (2 days) and long-term cultures, but long-term cultures had lower levels of oxidative stress. The primary reactive oxygen species appeared to be superoxide, and ROS indicators were lowered with the addition of superoxide dismutase (SOD). No cyto- or genotoxic effects were apparent using the XTT, trypan-blue exclusion, and colony-forming assays for viability and the Comet and Hprt gene mutation assays for genotoxicity. Nano-TiO(2) increased the percentage of cells in the G2/M phase of the cell cycle, but this effect did not appear to influence cell viability or cell division. Cellular Ti content was dose-dependent, but chronically exposed cells had lower amounts than acutely exposed cells. CHO cells appear to adapt to chronic exposure to nano-TiO(2) and detoxify excess ROS possibly through upregulation of SOD in addition to reducing particle uptake.

Elections in Africa are today the undisputed ticket to regime legitimacy. However, as much of sub-Saharan Africa embraces elections, they have also set up a death match between competing elites—turning elections into the single most destabilizing event in Africa. When Uganda went to the polls in February 2011, it did so under great pressure that elections provide its ruler of 25 years, Yoweri Museveni, with a legitimate claim to power. However, the wanton misuse of public funds weakened the economy, sparking Egypt-style riots that were brutally suppressed and revealing the vulnerability of Uganda's institutions of governance.

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5-Fluoro-5'-(2-oxo-1,3,2-oxazaphosphorinan-2-yl)-2'-deoxyuridine (1a) and 5-fluoro-5'-(2-oxo-1,3,2-dioxaphosphorinan-2-yl)-2'-deoxyuridine (1b) were prepared by reaction of 5-fluoro-2'-deoxyuridine (7a) and phosphoryl chloride with 3-amino-1-propanol and 1,3-propanediol, respectively. The thymidine analogues, 1c and 1d, were prepared similarly from thymidine. Compound 1b was synthesized in better yield from 13a and trimethylene phosphate with triphenylphosphine/diethyl azodicarboxylate as a condensing agent. Compounds 1a-d were resistant to degradation by 5'-nucleotidase, alkaline phosphatase, venom phosphodiesterase, and crude snake venom. None of these compounds were significantly biotransformed when incubated with mouse hepatic microsomal preparations in the presence of an NADPH-generating system. When administered intraperitoneally (ip) for 5 consecutive days, 1a was nearly as effective as 5-fluorouracil at prolonging the life spans of BDF1 mice implanted intraperitoneally with leukemia P-388. However, much larger dosages of 1a were required for optimal activity. Compound 1b administered similarly was only marginally effective. Neither 1a nor 1b was active against a P-388 mutant resistant to 5-fluorouracil.