2,451 research outputs found
Encapsulation of Antimicrobial Peptides in Bicontinuous Microemulsions for Topical Delivery to Surgical Site Infections and Chronic Wounds
Surgical site infections and chronic wounds, especially those caused by antibiotic-resistant microorganisms, result in hospitalization and fatalities each year. Methods to prevent these infections, such as cleaning and preparing medical tools, have had minimal success in preventing infections. Further, antibiotic treatments have become less successful in treating infections and wounds because of antibiotic-resistant bacteria. Antimicrobial peptides (AMP) are a possible treatment solution for wound infections. AMPs are oligopeptides that occur in nature or can be synthesized in vitro which possess a broad spectrum of antimicrobial activity against bacteria and other harmful microorganisms. AMPs operate by disrupting the packing arrangements of biomembranes in prokaryotes through their insertion into negatively charged phospholipid bilayers. However, many AMP products fail clinical trials because of their difficulty to be encapsulated and delivered at high concentrations in an active form. This project proposed the use of bicontinuous microemulsions (BMEs) as a possible system to encapsulate and deliver AMPs. BMEs are thermodynamically stable mixtures consisting of a surfactant, oil, aqueous mixture, and sometimes a cosurfactant. They are optically clear and the surfactant(s) in BMEs solubilize nearly equal amounts of oil and water creating elongated nanodomains. AMPs are typically cationic, and the following hypothesis was tested: BMEs created with anionic surfactants would induce a more highly folded, hence more biologically active, conformation for melittin. Several different BME systems composed of biocompatible oils were identified and evaluated for their ability to encapsulate melittin, a model AMP, and to test the system’s antimicrobial activity. Small-angle x-ray scattering showed melittin effected the BMEs quasi-periodic repeat distance and correlation lengths. Circular dichroism data showed a higher percentage of melittin was in its active form when encapsulated in a BME compared to an aqueous solution. Fluorescence measurements showed melittin resided within the surfactant monolayers of the BMEs. Antimicrobial diffusion assays proved that there was a larger zone of inhibition against bacteria commonly found in surgical site infections and chronic wounds than the BMEs without melittin. This research was successful in adding an AMP into BMEs created with biocompatible materials and may be a viable option in combating the rise in antibiotic-resistant organisms
Certain Elastic Properties of Phosphor-Bronze Wires
The work by Guthe, Guthe and Sieg, and Sieg, on platinumiridium wires when used as suspensions for torsion pendulums, showed some remarkable elastic properties of that alloy. The principal one of these was the variation of the period with the amplitude of vibration. It was these studies that made it seem very desirable to test other alloys commonly used for suspensions, by a similar method
Handling and analysis of ices in cryostats and glove boxes in view of cometary samples
Comet nucleus sample return mission and other return missions from planets and satellites need equipment for handling and analysis of icy samples at low temperatures under vacuum or protective gas. Two methods are reported which were developed for analysis of small icy samples and which are modified for larger samples in cometary matter simulation experiments (KOSI). A conventional optical cryostat system was modified to allow for transport of samples at 5 K, ion beam irradiation, and measurement in an off-line optical spectrophotometer. The new system consists of a removable window plug containing nozzles for condensation of water and volatiles onto a cold finger. This plug can be removed in a vacuum system, changed against another plug (e.g., with other windows (IR, VIS, VUV) or other nozzles). While open, the samples can be treated under vacuum with cooling by manipulators (cut, removal, sample taking, irradiation with light, photons, or ions). After bringing the plug back, the samples can be moved to another site of analysis. For handling the 30 cm diameter mineral-ice samples from the KOSI experiments an 80x80x80 cm glove box made out of plexiglass was used. The samples were kept in a liquid nitrogen bath, which was filled from the outside. A stream a dry N2 and evaporating gas from the bath purified the glove box from impurity gases and, in particular, H2O, which otherwise would condense onto the samples
Notes on Certain Elastic Peculiarities of Phosphor Bronze Wires
Some previous work by one of the authors with wires of an alloy of platinum-iridium, portions of which work were published in these Proceedings, indicated that when the wires were used as suspensions for torsion pendulums, the relations between the period of vibration and the amplitude were exceedingly complicated. The effect of drawing these wires was dealt with in another paper. In all these papers referred to, the statement was made that similar tests should be applied to some of the more common wires in the hope of finding similar, even though smaller effects. Through press of work these experiments have been deferred until the present year. This particular paper will deal with but one feature of the work, namely, the effect of drawing on the elastic nature of phosphor bronze wires. The writers are indebted to the American Electrical Works, of Phillipsdale, Rhode Island, for kindly furnishing them with specimens of the wires
Verbraucherwissenschaft: in welchen Themenbereichen wird geforscht?
Spitzenreiter der Verbraucherforschung sind die Themenbereiche Nachhaltigkeit, Ernährung und Gesundheit, Verbraucherverhalten und spezielle Verbrauchergruppen - so die Ergebnisse einer Momentaufnahme. Für Nachhaltigkeit und Verbraucherverhalten melden die befragten Forscher zudem auch einen dringenderen Forschungsbedarf als für andere Themenfelder der Verbraucherforschung an. Hingegen sind Märkte, die in der verbraucherpolitischen Diskussion als zu komplex und intransparent gelten wie soziale Sicherung, Netzwerk- und Finanzdienstleistungen, auf der Arbeitsskala wie auch beim Forschungsbedarf nur im mittleren Feld vertreten. Die Ergebnisse der Befragung zeigen, dass die jüngsten Initiativen zur Vernetzung in der Verbraucherforschung in der Wissenschaft offensichtlich noch nicht angekommen sind
Hitzschlag mit Alpha-Koma: Ein Fallbericht
Zusammenfassung: Wir berichten über einen 41-jährigen komatösen Patienten, der einen schwer verlaufenden Hitzschlag mit einer Körperkerntemperatur von 41,5°C erlitt. Der klinische Verlauf wurde kompliziert durch eine akute systemische inflammatorische Reaktion und Multiorganversagen. Das EEG zeigte ein prognostisch ungünstiges Alpha-Koma ohne Reaktivität auf externe Stimuli. Der Patient erlangte das Bewusstsein wieder und wurde nach 16Tagen aus der intensivmedizinischen Behandlung entlassen. Im weiteren Verlauf entwickelte sich eine zerebrale Toxoplasmose, die mit einer Kombinationstherapie aus Sulfadiazin und Pyrimethamin behandelt wurde. Nach 65Tagen erfolgte eine Verlegung in eine Neurorehabilitationsklinik mit einem moderaten neurologischen Defizi
High-energy picosecond Nd:YVO4 slab amplifier for OPCPA pumping
We demonstrate 12-ps pulses with up to 0.6-mJ pulse energy at repetition rates of 50 kHz and 100 kHz from a Nd:YVO4 slab amplifier built in a simple four-pass configuration. Excellent noise performance with pulse energy fluctuations below 0.8% rms has been achieved by using 10-μJ seed pulses from a highly stable industrial laser system and moderate gain (30-46) in the slab amplifie
Description of non-specific DNA-protein interaction and facilitated diffusion with a dynamical model
We propose a dynamical model for non-specific DNA-protein interaction, which
is based on the 'bead-spring' model previously developed by other groups, and
investigate its properties using Brownian Dynamics simulations. We show that
the model successfully reproduces some of the observed properties of real
systems and predictions of kinetic models. For example, sampling of the DNA
sequence by the protein proceeds via a succession of 3d motion in the solvent,
1d sliding along the sequence, short hops between neighboring sites, and
intersegmental transfers. Moreover, facilitated diffusion takes place in a
certain range of values of the protein effective charge, that is, the
combination of 1d sliding and 3d motion leads to faster DNA sampling than pure
3d motion. At last, the number of base pairs visited during a sliding event is
comparable to the values deduced from single-molecule experiments. We also
point out and discuss some discrepancies between the predictions of this model
and some recent experimental results as well as some hypotheses and predictions
of kinetic models
Text based user comments as a signal for automatic language identification of online videos
Identifying the audio language of online videos is crucial for industrial multi-media applications. Automatic speech recognition systems can potentially detect the language of the audio. However, such systems are not available for all languages. Moreover, background noise, music and multi-party conversations make audio language identification hard. Instead, we utilize text based user comments as a new signal to identify audio language of YouTube videos. First, we detect the language of the text based comments. Augmenting this information with video meta-data features, we predict the language of the videos with an accuracy of 97% on a set of publicly available videos. The subject matter discussed in this research is patent pending
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