An evaluation of gravity waves and gravity wave sources in the Southern Hemisphere in a 7 km global climate simulation.

In this study, gravity waves (GWs) in the high-resolution GEOS-5 Nature Run are first evaluated with respect to satellite and other model results. Southern Hemisphere winter sources of non-orographic GWs in the model are then investigated by linking measures of tropospheric non-orographic gravity wave generation tied to precipitation and frontogenesis with absolute gravity wave momentum flux in the lower stratosphere. Finally, non-orographic GW momentum flux is compared to orographic gravity wave momentum flux and compared to previous estimates. The results show that the global patterns in GW amplitude, horizontal wavelength, and propagation direction are realistic compared to observations. However, as in other global models, the amplitudes are weaker and horizontal wavelengths longer than observed. The global patterns in absolute GW momentum flux also agree well with previous model and observational estimates. The evaluation of model non-orographic GW sources in the Southern Hemisphere winter shows that strong intermittent precipitation (greater than 10 mm h-1) is associated with GW momentum flux over the South Pacific, whereas frontogenesis and less intermittent, lower precipitation rates (less than 10 mm h-1) are associated with GW momentum flux near 60°S. In the model, orographic GWs contribute almost exclusively to a peak in zonal mean momentum flux between 70 and 75°S, while non-orographic waves dominate at 60°S, and non-orographic GWs contribute a third to a peak in zonal mean momentum flux between 25 and 30°S.

Liquid Chromatography-Tandem Mass Spectrometry Analysis of Opioids, Benzodiazepines, Cannabinoids, Amphetamines, and Cocaine in Biological and Other Specimens.

The use of liquid chromatography (LC) coupled with tandem mass spectrometry (MS/MS) or single-stage mass spectrometry (MS) is making significant inroads in the analyst's compendium of instrumentation available for the analysis of drugs in biological fluids, tissues, and other specimens of interest. LC/MS(/MS) has the unique capability of analyzing substances frequently not analyzable by any other means. Furthermore, LC/MS(/MS), particularly LC/MS/MS instrumentation, has shown a precipitous drop in cost, making it more accessible to the smaller laboratories. As such, an increasing number of methods for the analysis of drugs of abuse have been published using LC/MS(/MS) - in particular, those methods associated with LC/MS/MS. However, these methods are not without certain endemic problems/limitations such as ion source selection, matrix effects, endogenous interferences, and interlibrary matching of spectra. This review seeks to show what progress is being made to circumvent the perceived limitations of LC/MS(/MS). It presents methodologies for selected drugs of abuse (opioids, benzodiazepines, cannabinoids, cocaine, and the amphetamines) that have been developed in recent years for analysis in blood, urine, hair, and oral fluids, as well as certain other specimens. Emphasis is primarily directed toward those methodologies that have been developed recently for LC/MS/MS, but LC/MS methods are also addressed where appropriate.

Effect of magnification lenses on student operator posture.

A distinct body of literature supports the association between clinical postures of the dental practitioner and work-related musculoskeletal disorders (WRMD). Several aids or devices have been tested to improve clinical posture in the interest of decreasing WRMD. The use of magnification lenses while performing dental procedures may increase the quality of work and decrease the likelihood of musculoskeletal problems. To date, only anecdotal and personal opinions had existed regarding the benefits of using magnification lenses, and no empirical evidence had authenticated the contention that use of magnification lenses exerts a positive change in operator posture. The objective of this study was to assess the effect magnification lenses had on the posture of dental hygiene students. Using a randomized crossover design, researchers videotaped nineteen senior dental hygiene students performing an intra-oral procedure with and without the use of magnification lenses. The tapes were then evaluated by a panel of five dental hygiene educators calibrated in the use of Branson's Posture Assessment Instrument (PAI). Results of a paired t-test indicate that the posture of the students while wearing magnification lenses was more acceptable (p=.019) than when wearing traditional safety glasses. Results of this study indicate a quantifiable change in acceptability of posture for clinicians wearing magnification lenses and suggest that the use of such lenses in dental education may be warranted.

Nitrobenzene compounds inhibit expression of VCAM-1.

A series of nitrobenzene compounds has been discovered as potent inhibitors of VCAM-1 expression and, therefore, potential drug candidates for autoimmune and allergic inflammatory diseases. Structure-activity relationship (SAR) studies showed that a nitro group and two other electron-withdrawing groups are essential for these compounds to be potent inhibitors of VCAM-1 expression.

The photodecomposition of tryptophan peptides.

Aqueous solutions of the four tryptophan peptides, Ala-Trp-Val, Val-Trp-Ala, Ala-Ala-Trp-Val and Ala-Gly-Trp-Leu, have been irradiated with the light of wavelength greater than 295 nm. The major changes were destruction of the tryptophan residue, liberation of ammonia and the formation of photoproducts of increased molecular weight. Up to 40% of Ala-Ala-Trp-Val and Ala-Gly-Trp-Leu were converted to products with molecular weights ranging from two to four times those of the original tetrapeptides. Most of the yellow material formed during irradiation in air was present in the high molecular weight fractions. Irradiation of Ala-Gly-[14C]Trp-Leu gave the following identifiable photoproducts: Ala-Gly-Asp-Leu, Ala-Gly-(N'formyl)Kyn-Leu, Ala-Gly-Oia-Leu, and ammonia, where Kyn means kynurenine and Oia, beta-(3-oxindolyl)alanine.

The complete enzymic hydrolysis of crosslinked proteins.

Procedures used for the complete enzymic hydrolysis of proteins are reviewed. The successful application of complete enzymic hydrolysis in the detection of naturally occurring isopeptide crosslinks and various other types of chemically introduced crosslinks is described. The method may fail if the level of crosslinking is too high, or if crosslinking is accompanied by racemization. Although it is usual to cleave disulphide crosslinks prior to enzymic digestion, the necessity for this in all cases is questioned.