Real-time synchronous imaging of electromechanical resonator mode and equilibrium profiles.

Interferometric imaging of normal mode dynamics in electromechanical resonators, oscillating in the rf regime, is demonstrated by synchronous imaging with a pulsed nanosecond laser. Profiles of mechanical modes in suspended thin film structures and their equilibrium profiles are measured through all-optical Fabry-Perot reflectance fits to the temporal traces. As a proof of principle, the mode patterns of a microdrum silicon resonator are visualized, and the extracted vibration modes and equilibrium profile show good agreement with numerical estimations.

Conformational analysis of single DNA molecules undergoing entropically induced motion in nanochannels.

We have used the interface between a nanochannel and a microchannel as a tool for applying controlled forces on a DNA molecule. A molecule, with a radius of gyration larger than the nanochannel width, that straddles such an interface is subject to an essentially constant entropic force, which can be balanced against other forces such as the electrophoretic force from an applied electric field. By controlling the applied field we can position the molecule as desired and observe the conformation of the molecule as it stretches, relaxes, and recoils from the nanochannel. We quantify and present models for the molecular motion in response to the entropic, electrophoretic, and frictional forces acting on it. By determining the magnitude of the drag coefficients for DNA molecules in the nanostructure, we are able to estimate the confinement-induced recoil force. Finally, we demonstrate that we can use a controlled applied field and the entropic interfacial forces to unfold molecules, which can then be manipulated and positioned in their simple extended morphology.

Process for degradation of nitrobenzene: combining electron beam irradiation with biotransformation.

Electron beam irradiations of aqueous solutions containing 15-30 mg/L of nitrobenzene at 60 kGy dose removed 78% of the contaminant. Three mononitrophenols were detected as by-products of electron beam treatment of nitrobenzene. A mixed culture enriched on a mixture of 2-, 3-, and 4-nitrophenol degraded both the residual nitrobenzene and the nitrophenol products. Percentage removal of nitrobenzene increased with increasing electron beam dose. This observation led to the conceptual design of a two-stage electron beam microbial process for degradation of nitrobenzene. Three groups of pure isolates were characterized from the mixed culture based on their abilities to grow on cor- responding nitrophenol substrates: Group A, 2NP(-)3NP(-)4NP(+); Group B, 2NP(+)3NP(+)4NP(-); and Group C, 2NP(-)3NP(+)4NP(-). Bacteria that grew on 3-NP transformed nitrobenzene into ammonia in the electron beam-treated nitrobenzene samples.

No respite during sleep: heart-rate hyperreactivity to rapid eye movement sleep in angry men classified as Type A.

9 men scoring as Type A and Angry and 9 men scoring as Type B and Nonangry on the Jenkins Activity Survey and Spielberger's Trait Anger Expression completed a 1-min. mental arithmetic task and slept through 1 period of rapid eye movement. The Angry Type A scorers showed greater heart-rate increases from baseline to that during mental arithmetic and from nonrapid eye movements to periods of REM than the Nonangry Type B scorers. While the former showed equivalent reactivity to stressors while awake and asleep, the latter group showed less heart-rate reactivity during the period of REM than during mental arithmetic. Neither group yielded clear descriptions of their dreams, and no differences between groups were noted for ratings on aggressivity in dreams. It appears that Angry Type A scorers show cardiovascular hyperreactivity even when asleep in the lab.

Bromine and selenium in human aorta.

The bromine and selenium concentrations of healthy and atheromatous human aorta and of other organs are reported. No relation between age and concentration in the aorta is found. The selenium levels of the aorta are similar to those of other internal organs; the content of the three layers show no significant differences. The bromine concentrations of the media are higher than those of the other layers, which are similar to those of the internal organs. A possibly greater concentration of bromine in atheromatous medial tissue is indicated.

A suicide by ingestion of a mixture of copper, chromium and arsenic compounds.

A suicide resulting from the ingestion of copper, chromium and arsenic is reported. Death was delayed for 36 hours, during which time copper was rapidly eliminated from the body but chromium and arsenic remained in substantial quantities. The different metabolism of these elements is discussed and the tissue levels discovered are compared with the normal levels.

Bromine in human tissue.

The normal levels of bromine in human tissue are given and their use in the interpretation of levels found when over-exposure is a possibility is described. Bromine is "normally" distributed in human tissue as are essential trace elements. This allows a bromine (microgram) to chlorine (mg) ratio to be established (3.2) above which bromine exposure must be considered. The bromine concentrations in sections of hair can be used to establish the time of administration even when small amounts are ingested, but owing to the long half-life (about 15 days) found in human tissue interpretation after multiple doses may be difficult.

Scanning electron microscopy of evaporating ice.

Direct observation of evaporating ice with a scanning electron microscope indicates that the surfaces of single-crystal and polycrystalline ice are markedly different. In specimens of single-crystal ice the crystal planes are revealed by evaporation, whereas polycrystalline ice develops a fibrous surface.