Vitamin E (alpha-tocopherol) has been implicated in several cellular processes including signaling, transport, lipid membrane curvature, and several neurodegenerative disorders. Vitamin E imaging has been hindered by the inaccessibility of the molecule to traditional immunohistochemical methods. Using time-of-flight secondary ion mass spectrometry (ToF-SIMS), the distribution of major constituents in the cellular membrane of isolated neurons was investigated. There is a significant increase in the vitamin E signal at the soma-neurite junction compared to the cell as a whole (165 +/- 11% of that found across the cell, p = 0.004, n = 12). The observed membrane distribution suggests an important new role for vitamin E in neuronal function.

A new platform for oral delivery of paclitaxel (PTX) was developed through chemical conjugation of PTX to a low molecular weight chitosan (LMWC). The LMWC-PTX conjugate contained approximately 12 wt % PTX and showed greatly enhanced water solubility (>1 mg/mL) as compared to native PTX. The conjugate showed comparable IC 50 values to that of the parent PTX against human cancer cell lines. The pharmacokinetic data revealed approximately 42% of bioavailability after oral administration of 5 mg PTX/kg of the conjugate. When the conjugate (10 mg/kg based on PTX content) was administered orally to mice bearing xenograft or allograft tumors, the conjugate-treated group showed significant inhibition of tumor growth, which was comparable to that seen with PTX of the clinically available injected form, formulated in cremophor EL/ethanol (iv) but with much lower toxicity. Tracking I (125)-labeled conjugate showed that LMWC-PTX was likely to be absorbed mainly from the ileum and reach the blood as the intact conjugate.

No abstract

The role of hydrogen-containing surface species in the alkaline dissolution of aluminum was studied by secondary ion mass spectrometry ͑SIMS͒ and atomic force microscopy ͑AFM͒. The measurements revealed quasi-periodic nucleation and dissolution of large number densities of 10-100 nm size particles, during open-circuit dissolution in 1 M NaOH͑D͒ at room temperature. SIMS results using deuterated solutions, and prior Auger microprobe measurements, indicated that the particles were composed of aluminum hydride ͑deuteride͒, with an aluminum hydroxide ͑deuteroxide͒ surface layer. The measured open-circuit potential during dissolution was close to the Nernst potential of hydride oxidation. It was concluded that AlH 3 forms continuously during dissolution by reaction of cathodically generated hydrogen with the Al metal and is oxidized to aluminate ions ͓Al͑OH͒ 4 − ͔ in the accompanying anodic process. The present results are a direct confirmation of hydride formation on Al accompanying corrosion.

Noble-metal-oxide support catalysts have been demonstrated to be unique for electrocatalytic water oxidation in acidic media. Highly porous three-dimensional oxide supported can serve as an ideal platform to confine ultrasmall metal catalysts on specific sites and modulate their reactivity, resulting in the reduction of noble metal content in the catalyst by boosting the mass activity. However, due to poor control over the support morphology, geometricdriven shifts in mass activity of metal-oxide support catalysts for the oxygen evolution reaction in acidic media have not been realized. Herein, a nanoscale Kirkendall effect is exploited to produce and control a structural evolution yielding an oxygen-evolving catalyst that is highly efficient and robust in acidic medium. By selective reaction−diffusion under oxidizing conditions, the starting solid CoIr NC is directly transformed into an unprecedented Ir−Co 3 O 4 @Co 3 O 4 porous-core@shell hollow nanospheres (ICO PCSHS), in which an ultrasmall Ir catalyst is spatially isolated within a porous Co 3 O 4 -backbone core, encapsulated by a hollow Co 3 O 4 outer shell. With a low Ir content of 14 wt %, the iridium mass activity exhibited by ICO PCSHS-400 catalyst is 24 times higher than that of benchmark RuO 2 , substantially exceeding the known oxide-supported metal catalysts. More importantly, the electrocatalyst shows high stability during 8 h of continuous testing in acidic medium.