Morphological properties of Ag2SeTe nano thin films prepared by thermal evaporation.

Semiconducting silver selenide telluride (Ag2SeTe) thin films were prepared with different thicknesses onto glass substrates at room temperature using thermal evaporation technique. The structural properties were determined as a function of thickness by X-ray diffraction exhibiting no preferential orientation along any plane; however, the films are found to have peaks corresponding to mixed phase. The morphology of these films was studied using scanning electron microscope and atomic force microscopy respectively, and is reported. The morphological properties are found to be very sensitive to the thin film thickness. The composition of the films is also estimated using energy dispersive analysis using X-rays and are also reported.

Anaesthesia for spinal surgery in children.

Spinal surgery is performed in children of all age groups. Some of these children will have significant, other medical problems. For most, surgery will be performed in the prone position. Blood loss may be high for some types of surgery, and patients will benefit from use of a blood-sparing technique. Many patients will require spinal cord monitoring to assess cord function and to prevent neurological deficit.

A randomised comparison of a hand-held Neurotip and the Neuropen for assessing loss of touch sensation during spinal anaesthesia for caesarean section.

BACKGROUND: With spinal anaesthesia various methods may be used to assess the block to touch. We wished to compare the levels of block assessed using a non-standardised, assessor-dependent touch stimulus with those assessed when the same stimulus was applied in a standardised manner independent of the assessor. METHODS: In a double-blind, randomised study the levels of block to touch were assessed by two investigators, one using a hand-held Neurotip tester pin and the other using the same tester pin mounted in a spring loaded system (Neuropen). Both the testing device and the order of testing were randomised between the two observers. The dermatomes were marked on patients' torsos before surgery. RESULTS: Whole group data analysis in a Bland Altman plot demonstrated a median difference of 0 dermatomes between the two methods: the 5th, 25th, 75th, and 95th centiles of agreement being -2, -1, +1, and +2 dermatomes respectively. There were occasional wide differences in levels of block to touch with the Neuropen varying between seven dermatomes rostral to and four dermatomes caudal to the Neurotip. These differences were short-lived and did not affect clinical management. CONCLUSION: When comparing two very similar touch stimuli, one standardised and user-independent and one non-standardised, we observed occasional wide but short lived differences in the assessed levels of block to touch. Although these differences did not affect clinical management, whether more dissimilar touch testing methods might affect clinical management remains to be seen.

Synthesis and binding of new polyfluorinated aryl azides to alpha-chymotrypsin. New reagents for photoaffinity labeling.

The preparation of several new, water-soluble, polyfluorinated aryl azide reagents for use in photoaffinity labeling studies is described. The ability of some of these reagents and their nonfluorinated controls to noncovalently bind to alpha-chrymotrypsin is reported. It is found that polyfluorination does not interfere with ligand binding.

Exploratory photochemistry of fluorinated aryl azides. Implications for the design of photoaffinity labeling reagents.

A series of fluorinated aryl azides and fluorinated azidobenzoates were studied by laser flash photolysis techniques. Using the pyridine ylide probe method it was possible to determine whether a singlet nitrene or ring-expanded ketenimine ylide is the trappable intermediate that is generated at ambient temperature. It was determined that two fluorine substituents, ortho and ortho' substituted relative to the azide group, are required to retard ring expansion and allow bimolecular capture of the singlet nitrene. LFP of ortho, ortho' difluorinated aryl azides in methanol produces the ground triplet state of the nitrene. The results are consistent with chemical analysis of reaction mixtures. The implications of this data for the design of photoaffinity labeling reagents are discussed.