High throughput discovery of heteroaromatic-modifying enzymes allows enhancement of novobiocin selectivity

Glycosylated analogues of novobiocin, discovered using a broad library of enzymes, have 100-fold improved activity against breast, brain, pancreatic, lung and ovarian cancers and ablated associated off-target activity leading to an up to 2.7 × 10(4) fold increase in selectivity.     

Probing the spectral densities over the full three-dimensional momentum space

Electron momentum spectroscopy is often used to determine the spectral function of materials. It relies on the determination of the scattering angle of electrons with extremely high precision. In practice, it is important to calibrate these angles, and hence the momentum scales. Here we describe a method to do so and show how minor misalignments affect the measured momentum densities of Li₂O. Using the same procedure we further calibrated the momentum scale by measuring the spectral momentum density along a Brillouin zone boundary of a Si single crystal.     

Seltene Erden

Ohne Zusammenfassung     

Measurements of ultracold-neutron lifetimes in solid deuterium

We present the first measurements of the survival time of ultracold neutrons (UCNs) in solid deuterium (SD2). This critical parameter provides a fundamental limitation to the effectiveness of superthermal UCN sources that utilize solid ortho-deuterium as the source material. These measurements are performed utilizing a SD2 source coupled to a spallation source of neutrons, providing a demonstration of UCN production in this geometry and permitting systematic studies of the influence of thermal up-scatter and contamination with para-deuterium on the UCN survival time.     

Electron paramagnetic resonance spectroscopic studies of thermally generated free radicals in PMR-15 polyimide resins

PMR-15 is a high-performance thermoset polyimide resin that is used in many high-temperature applications. Postcured PMR-15 produces room-temperature electron paramagnetic resonance (EPR) spectra from stable freeradical species that are formed during the postcuring stages. The variable-temperature EPR spectral intensities show a minimum at T_min in the range ?60 to ?40°C, and a maximum at T_max in the range 80–120°C. The EPR intensities follow the inverse temperature dependence of Curie's law below T_min and are due to a stable free radical. The intensities then increase with increasing temperature between T_min and T_max. The free radical with such temperature dependence is not present below T_min and is undetectable by EPR at temperatures above T_max. These free radicals are generated during the postcuring process at elevated temperature above 310°C. The thermo-oxidative degradation involves free radicals generated during the postcuring process in the presence of oxygen gas. © 1993 John Wiley & Sons, Inc.     

A laser-interferometric dilatometer for thermal-expansion measurements of composites

A high-precision, Fizeau-type laser-interferometric dilatometer system has been developed for low-expansion composite materials. The strain resolution is about one microstrain. The system is automated to operate over a large temperature range and record data during the test. A technique has been developed to reduce the data in real time. The dilatometer system is described and thermal-expansion measurements for several fiber-reinforced and particle-filled composites are presented. Paper was presented at V International Congress on Experimental Mechanics held in Montreal, Quebec, Canada on June 10–15, 1984.