New mechanisms of 5-nitrofuran toxicity

Phenotypic screens and the target identification that follows can lead to surprising new connections between small molecules and targets. In this issue of Chemistry & Biology, Zhou and colleagues seek to understand the pigmentation of fish skin and end up uncovering an interesting clinical hypothesis about the trypanocidal compound nifurtimox.     

Cation self-diffusion and impurity diffusion in Fe2O3+

Cation self-diffusion D¹_Fe, parallel to the c axis has been measured as a function of temperature (1100–1300°C) and oxygen partial pressure p_o2 (2 × 10^?3-1 atm) in the same single crystals of Fe₂O₃ as those used by Chang and Wagner. Whereas the p_o2 dependence of D1_Fe, observed by Chang and Wagner has been confirmed, the absolute value of D¹_Fe and the activation enthalpy for self-diffusion are much higher than those reported by them. The various diffusion studies indicate that cation self-diffusion occurs by an interstitial-type mechanism. However, the sample-to-sample variations in D¹_Fe, suggest that all diffusion measurements may have been performed on samples where the defect concentrations are impurity controlled. Impurity diffusion of ⁶⁰Co, ⁵¹Cr, and ⁸⁸Y has also been measured as a function of p_o2 at 1200°C. The results indicate that these impurities diffuse by an interstitialcy mechanism in Fe₂O₃.     

Pore structures in an implantable sol-gel titania ceramic device used in controlled drug release applications: A modeling study

Several process variables, which may be helpful in optimizing the rate at which drugs are released from implantable, sol-gel titania devices have been identified in this study. The controlled rate of drug release is compared for two different anticonvulsant drugs, valproic acid and sodic phenytoin. Contrary to what one might expect, when the concentration is increased in the titania reservoir the rate of initial drug delivery decreases. This is a desirable result, because it may reduce the danger of a high initial discharge, which may harm the epileptic rat. The structure of the porous structure within the titania network has been studied using a generalized form of the BET equation which considers only n layers. In general, following an initial discharge, the rate at which the drug is released will increase with the increasing concentration. Pore mouth blocking can present a problem. However, this problem tends to disappear following the initial discharge. The extent of drug loading is a useful variable parameter, which can be adjusted in order to deliver the amount of drug required in a given application.     

Status and applications of cryogenic detectors

An overview of the actual technical status and achievements of different types of cryogenic detectors is given. Typical applications in several fields are discussed with emphasis put on appropriate nuclear experiments for the planned Princeton facility. The possibility of implementation in low temperature nuclear orientation experiments will be explored.     

On the finite element approximation of incompressible flows of an electrically conducting fluid

We consider the finite element approximation of incompressible flows field of an electrically conducing fluid in the presence of a magnetic where it is assumed that this field is prescribed. A weak form is chosen that is similar in some respects to a weak form used by many authors for the Navier-Stokes equations. Existence and uniqueness results are presented for the weak problem. A finite element Algorithm is given for the approximate solution of the weak problem and error estimates are derived.     

Second harmonic generation from alternating langmuir-blodgett films

We report here the investigation of the second harmonic generation from a non-centrosymmetric alternating Langmuir-Blodgett film of ω-tricosenoic acid and highly polarisable merocyanine dye. Results for films containing one, two and three layers of the merocyanine dye are described.     

Electronic structure and bonding in CaH2: Experiment and theory

Synchrotron radiation photoemission studies of Ca and CaH₂ reveal changes in the electronic structure and bonding which directly reflect metal-hydrogen interactions. The results indicate similarities between the saline dihydrides and the transition metal dihydrides, particularly the energy location and width of the bonding band states. Combined with APW band calculations for CaH₂ in the CaF₂ structure, they provide new insight regarding bonding in hydrides.