3,344 research outputs found

    Evolution of plant ribosome-inactivating proteins

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    This contribution presents an updated analysis of the evolution of ribosome-inactivating proteins (RIPs) in plants. All evidence suggests that an ancestor of modern seed plants developed the RIP domain at least 300 million years ago. This ancestral RIP domain gave rise to a direct lineage of type 1 RIPs (i.e. primary type 1 RIPs) still present today in many monocots and at least one dicot. In a later stage a plant succeeded in fusing the RIP domain to a duplicated ricin-B domain acquired from a bacterium. The resulting ancestral type 2 RIP gave rise to all modern type 2 RIPs and by domain deletion to different lines of ‘secondary’ type 1 RIPs and ricin-B type lectins. In a more recent past at least three other domain fusions took place in the family Poaceae whereby type AC1 (type 3), type AC2 and type AD chimeric forms were generated

    Transfer of Sulfamethazine from Contaminated Beeswax to Honey

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    A liquid chromatographic tandem mass spectrometric method for the determination of sulfa drugs in beeswax was developed. When performing residue control on beeswax intended for the fabrication of wax foundations, residues of sulfonamides were found. A migration test was set up to study whether sulfonamide-containing beeswax could lead to the contamination of honey. The higher the concentration of sulfamethazine doped in the wax, the higher was the concentration of sulfamethazine found in the honey. The maximum transfer was 15.6, 56.9, and 29.5% of the initial amount spiked in the wax foundation. In a second experiment, the percentage of sulfamethazine migrating from medicated winter feed to beeswax in relation to the concentration in the syrup and the contact time was studied. The maximum transfer of sulfamethazine from medicated sucrose syrup to beeswax was 3.1%

    Enkele aspekte van die huidige posisie van die openbare rekenmeester en ouditeur

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    By hierdie geleentheid vra ek u aandag vir enkele aspekte van die posisie van die Openbare Rekenmeester en Ouditeur en sy werksaamhede onder huidige omstandighede

    The infrared spectra of very large, compact, highly symmetric, polycyclic aromatic hydrocarbons (PAHs)

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    The mid-infrared spectra of large PAHs ranging from C54H18 to C130H28 are determined computationally using Density Functional Theory. Trends in the band positions and intensities as a function of PAH size, charge and geometry are discussed. Regarding the 3.3, 6.3 and 11.2 micron bands similar conclusions hold as with small PAHs. This does not hold for the other features. The larger PAH cations and anions produce bands at 7.8 micron and, as PAH sizes increases, a band near 8.5 micron becomes prominent and shifts slightly to the red. In addition, the average anion peak falls slightly to the red of the average cation peak. The similarity in behavior of the 7.8 and 8.6 micron bands with the astronomical observations suggests that they arise from large, cationic and anionic PAHs, with the specific peak position and profile reflecting the PAH cation to anion concentration ratio and relative intensities of PAH size. Hence, the broad astronomical 7.7 micron band is produced by a mixture of small and large PAH cations and anions, with small and large PAHs contributing more to the 7.6 and 7.8 micron component respectively. For the CH out-of-plane vibrations, the duo hydrogens couple with the solo vibrations and produce bands that fall at wavelengths slightly different than their counterparts in smaller PAHs. As a consequence, previously deduced PAH structures are altered in favor of more compact and symmetric forms. In addition, the overlap between the duo and trio bands may reproduce the blue-shaded 12.8 micron profile.Comment: ApJ, 36 pages, 9 fig

    WWW (When Websites Work): Students’ Perceptions of Their Engagement When Using a Website Creation Tool

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    When students find value in technology and can apply that technology in their learning and beyond, they become more actively engaged in the classroom. After having first-year seminar students use Web 2.0 technology, specifically a website creation tool as part of an assignment, they participated in a survey to provide feedback over their engagement in creating a Google Sites® website. Quantitative and qualitative data was collected and analyzed to determine students’ perceptions of their engagement when using website creation tools to complete a modified discussion assignment. Results indicated students were significantly more engaged than the normal population when they used Google Sites® as part of their lesson. Primarily positive feedback was received from the participants which revealed three emerging themes - peer collaboration, attaining new skills, and various expressions of creativity. Based upon the findings, recommendations are presented to support faculty interested in using website creation tools as an assignment to enhance student engagement

    Intracardiac air- the "hospital killer' identified?

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    Venous access is an essential part of caring for the sick neonate. The primary problem with catheters, whether peripherally or centrally placed, is the difficulty in maintaining them, the development of phlebitis and systemic infection, and fluid extravasation. A lesser known complication is the development of venous air embolism (VAE), as described in the 4 cases presented. We agree with others that VAE in newborn infants may occur more frequently than expected and emphasise the fact that it is preventable and that careful attention must be given to the techniques of preparing venous infusions. As health professionals (medical and nursing) we should take a harder line and regard these events as medically negligent until proven otherwise. We should take full responsibility for equipment, the connections, the infusate and the monitoring thereof. Unfortunately, the prognosis for this condition remains poor and it is unclear whether an increased awareness of this condition would influence outcome.  Manufacturers of intravenous fluids should produce products devoid of air in order to reduce the risk of venous air embolism

    Satellite Monitoring of Public Transport

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