Combinatorial chemistry in glycobiology

The application of combinatorial chemistry to glycobiology historically has proven challenging due to numerous synthetic hurdles. The advent of novel methodologies has enabled the production of natural as well as mimetic analogues for proof-of-concept experiments and SAR. This review highlights some of the recent synthetic advances in combinatorial carbohydrate synthesis. The application of carbohydrate libraries in glycobiology is also discussed.     

Dark matter results from 100 live days of XENON100 data

We present results from the direct search for dark matter with the XENON100 detector, installed underground at the Laboratori Nazionali del Gran Sasso of INFN, Italy. XENON100 is a two-phase time-projection chamber with a 62 kg liquid xenon target. Interaction vertex reconstruction in three dimensions with millimeter precision allows the selection of only the innermost 48 kg as the ultralow background fiducial target. In 100.9 live days of data, acquired between January and June 2010, no evidence for dark matter is found. Three candidate events were observed in the signal region with an expected background of (1.8 ± 0.6) events. This leads to the most stringent limit on dark matter interactions today, excluding spin-independent elastic weakly interacting massive particle (WIMP) nucleon scattering cross sections above 7.0 × 10(-45) cm(2) for a WIMP mass of 50 GeV/c(2) at 90% confidence level.     

Large-scale failure modes of dielectric elastomer actuators

Dielectric elastomer actuators (DEAs) show promise for robotic and mechatronic applications. However, to date, these actuators have experienced high rates of failure that have prevented their practical application. Here, large scale modes of failure of DEAs and their performance limits are studied. The objective is to provide design guidelines and bound the performance of DEAs that avoid failure. An idealized DEA is modeled and its failure is predicted as a function of film pre-stretch used during actuator fabrication, actuation voltage, and stretch rate. Three failure modes are considered: pull-in, dielectric strength, and material strength. Each failure mode is shown to dominate for different combinations of pre-stretch and stretch rate. High stretch rates lead to dielectric strength failure while low stretch rates lead to pull-in failure. Material strength failure is less important for most cases. Model predictions are validated experimentally using practical DEAs operating under load. This study suggests that DEAs cannot be operated reliably under load for long periods of time or low stretch rates due to pull-in failure limitations. To be reliable, DEAs must be used for short periods of time with high stretch rates.     

Prisoner's dilemma and clusters on small‐world networks

The structure of interaction plays an important role in the outcome of evolutionary games. This study investigates the evolution of stochastic strategies of the prisoner's dilemma played on structures ranging from lattices to small world networks. Strategies and payoffs are analyzed as a function of the network characteristics of the node they are playing on. Nodes with lattice‐like neighborhoods tend to perform better than the nodes modified during the rewiring process of the construction of the small‐world network. © 2007 Wiley Periodicals, Inc. Complexity 12:22–36, 2006     

Fine-structure effects in relativistic calculations of the static polarizability of the helium atom

We use the relativistic configuration-interaction method and the model potential method to calculate the scalar and tensor components of the dipole polarizabilities for the excited states 1s3p ³ P ₀ and 1s3p ³ P ₂ of the helium atom. The calculations of the reduced matrix elements for the resonant terms in the spectral expansion of the polarizabilities are derived using two-electron basis functions of the relativistic Hamiltonian of the atom, a Hamiltonian that incorporates the Coulomb and Breit electron-electron interactions. We formulate a new approach to determining the parameters of the Fuss model potential. Finally, we show that the polarizability values are sensitive to the choice of the wave functions used in the calculations. Zh. éksp. Teor. Fiz. 115, 494–504 (February 1999)     

AES chemunex ADIAFOOD detection system for Listeria spp. environmental sample testing

The ADIAFOOD Detection System for the detection of Listeria species from environmental surfaces is based on real-time PCR technology and allows rapid pathogen detection within 21 h. The strength of the ADIAFOOD technology resides in its ability to rapidly and accurately detect Listeria species present on surfaces, such as stainless steel, plastic, ceramic, and sealed concrete. The technology is easy to use and versatile.