Electromagnetic characterization of carbon nanotube films subject to an oxidative treatment at elevated temperature.

Electromagnetic characterization of CNT films fabricated by thermal decomposition of SiC has been performed. Purification and/or uncapping treatment conditions at an elevated temperature of 400 degrees C under flowing oxygen or carbon dioxide have been studied. A near field microwave microscope was used to measure the real and imaginary parts of the complex permittivity of CNT films through the frequency shift and the change in reciprocal quality factor between two extreme positions of an evanescent microwave probe-tip (in contact with the sample, and away from interaction with it). A theoretical two-point model was proposed to confirm experimental data, which showed poor conductivity of the CNT film as grown but has slight improvement after 40 min treatment.

Contracting for safety with patients: clinical practice and forensic implications.

The contract for safety is a procedure used in the management of suicidal patients and has significant patient care, risk management, and medicolegal implications. We conducted a literature review to assess empirical support for this procedure and reviewed legal cases in which this practice was employed, to examine its effect on outcome. Studies obtained from a PubMed search were reviewed and consisted mainly of opinion-based surveys of clinicians and patients and retrospective reviews. Overall, empirically based evidence to support the use of the contract for safety in any population is very limited, particularly in adolescent populations. A legal review revealed that contracting for safety is never enough to protect against legal liability and may lead to adverse consequences for the clinician and the patient. Contracts should be considered for use only in patients who are deemed capable of giving informed consent and, even in these circumstances, should be used with caution. A contract should never replace a thorough assessment of a patient's suicide risk factors. Further empirical research is needed to determine whether contracting for safety merits consideration as a future component of the suicide risk assessment.

Microwave characterization of nanostructured ferroelectric Ba(0.6)Sr(0.4)TiO(3) thin films fabricated by pulsed laser deposition.

A series of nanostructured ferroelectric thin films of barium strontium titanate were fabricated using a pulsed laser deposition system with real-time in situ process control. Pulsed laser deposition parameters were controlled during the growth of nanostructured thin films for use in the development of high frequency tunable microwave devices. The thin films were all grown at the same substrate temperature and laser beam energy density, but the chamber oxygen partial pressure (COPP) was varied systematically from 19 mTorr through 1000 Torr. Structural and electromagnetic characterization was performed using atomic force microscopy and evanescent microwave microscopy, respectively. Atomic force microscopy showed a linear increase in grain size with increases in the ambient oxygen pressure from 38 to 150 mTorr and from 300 mTorr to 1000 Torr. The correlation of the microwave properties with the epitaxial film microstructure can be attributed to stresses and polarizability in the film. Microwave characterization showed that a COPP of 75 mTorr yielded the most desirable film in terms of tunability and loss tangent over a wide frequency range.

Biological infrared imaging and sensing.

A variety of thermoreceptors are present in animals and insects, which aid them in hunting, feeding and survival. Infrared (IR) imaging pit organs in Crotaline and Boid snakes enable them to detect, locate and apprehend their prey by detecting the IR radiation they emit. IR pit organs of common vampire bats (Desmodus rotundus) enable them to detect IR radiation emitted by blood-rich locations on homeothermic prey. The beetle Melanophila acuminata locates forest fires by IR-detecting pit organs in order to lay their eggs in freshly killed conifers. Thermoreceptors located in the wings and antennae of darkly pigmented butterflies (Pachliopta aristolochiae and Troides rhadamathus plateni) protect them from heat damage while sun basking. Blood-sucking bugs (Triatoma infestans) are speculated to possess thermoreceptors, which enable them to perceive the radiant heat emitted by homeothermic prey and estimate its temperature at a distance. This is a review of the diverse types of biological thermoreceptors, their structure and function, and how electron microscopy has been instrumental in determining their ultrastructure.