Enhanced energy transport in genetically engineered excitonic networks.

One of the challenges for achieving efficient exciton transport in solar energy conversion systems is precise structural control of the light-harvesting building blocks. Here, we create a tunable material consisting of a connected chromophore network on an ordered biological virus template. Using genetic engineering, we establish a link between the inter-chromophoric distances and emerging transport properties.

Enhanced downconversion of UV light by resonant scattering of aluminum nanoparticles.

Metallic nanoparticles are known to enhance nonlinear optical processes due to a local enhancement of the optical field. This strategy has been proposed to enhance downconversion in thin film solar cells, but has various disadvantages, among which is the fact that the enhancement occurs only in a tiny volume close to the particles. We report on a very different physical mechanism that can lead to significant downconversion enhancement, namely, that of resonant light scattering, and which is a large volume effect.

Hyperhomocysteinemia and arteriovenous fistula thrombosis in hemodialysis patients.

Background: To date, the relationship between vascular access (VA) failure and plasma total homocysteine level has been investigated only in mixed dialysis populations (ie, patients with a native arteriovenous [AV] fistula or arterial graft), whereas almost no data exist for hemodialysis patients with a native AV fistula.

Methods: In this prospective cohort study, we examined the relationship between plasma total homocysteine level and the methylenetetrahydrofolate reductase (MTHFR) gene and VA-related incident morbidity in a cohort of 205 hemodialysis patients, all with a native AV fistula.

Results: During follow-up, 78 patients experienced 1 or more VA thrombotic episodes.

Weak limits for quantum random walks.

We formulate and prove a general weak limit theorem for quantum random walks in one and more dimensions. With X(n) denoting position at time n, we show that X(n)/n converges weakly as n--> infinity to a certain distribution which is absolutely continuous and of bounded support. The proof is rigorous and makes use of Fourier transform methods.

Salivary and lacrimal secretion is reduced in patients with ESRD.

Background: A reduction in salivary and lacrimal secretion has been described in several diseases. However, such alterations have not been investigated fully in patients with chronic renal failure. The aim of the present study is to estimate the frequency of alterations in salivary and lacrimal secretion in long-term hemodialysis patients.