Bone remodeling in adult rats' condyles under mechanical strain

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Definition of Brittleness: Connections Between Mechanical and Tribological Properties of Polymers.

The increasing use of polymer-based materials (PBMs) across all types of industry has not been matched by sufficient improvements in understanding of polymer tribology: friction, wear, and lubrication. Further, viscoelasticity of PBMs complicates characterization of their behavior. Using data from micro-scratch testing, it was determined that viscoelastic recovery (healing) in sliding wear is independent of the indenter force within a defined range of load values. Strain hardening in sliding wear was observed for all materials-including polymers and composites with a wide variety of chemical structures-with the exception of polystyrene (PS). The healing in sliding wear was connected to free volume in polymers by using pressure-volume-temperature (P-V-T) results and the Hartmann equation of state. A linear relationship was found for all polymers studied with again the exception of PS. The exceptional behavior of PS has been attributed qualitatively to brittleness. In pursuit of a precise description of such, a quantitative definition of brittleness has been defined in terms of the elongation at break and storage modulus-a combination of parameters derived from both static and dynamic mechanical testing. Furthermore, a relationship between sliding wear recovery and brittleness for all PBMs including PS is demonstrated. The definition of brittleness may be used as a design criterion in selecting PBMs for specific applications, while the connection to free volume improves also predictability of wear behavior

The impact of orthodontic treatment on the quality of life of adults

Poster Session - Theme: General Dentistry and Oral HealthThis journal suppl. entitled: Special Issue: Abstracts of the 2012 FDI Annual World Dental CongressAIM: To assess changes in oral health-related quality of life (OHRQoL) and occlusion following fixed orthodontic appliance therapy (FOAT). METHODS: A consecutive sample of 86 patients underwent FOAT. Occlusion was assessed pre- and post-treatment (>12 months) using the Peer Assessment Rating (PAR) and Index of Complexity, Outcome and Need (ICON). OHRQoL …postprin

Olanzapine and pulmonary embolism, a rare association: a case report

Venous thromboembolism is a very common pathological process for which there are many well known (and less well-known) predisposing factors. Likewise, olanzapine is a commonly used anti-psychotic medication

Comparison of antimicrobial effect between Triclosan Toothpaste and Nono-Silver Toothpaste

This journal suppl. entitled: Special Issue: Abstracts of the 2012 FDI Annual World Dental CongressTheme: Preventive Dentistry - Caries (Oral Presentation)OBJECTIVE: To evaluate the antimicrobial effect of two commercial available toothpastes in vitro. MATERIALS AND METHODS: Two toothpastes: Colgate Total® toothpaste (triclosan containing) and NanoCare Nano silver® toothpaste (nano-silver containing) were investigated. The antimicrobial effect on bacteria planktonic status was tested by agar diffusion assay. A dual-species biofilm mod...postprin

Bismuth telluride-based thermoelectric materials: Coatings as protection against thermal cycling effects

Thermoelectric (TE) devices, both TE generators (TEGs) and TE coolers (TECs), have short service lives as TE materials undergo degradation from sublimation, oxidation and reactions in corrosive environments at high temperatures. We have investigated four high-temperature polymers (HTPs) as candidates for TE element coatings and/or TE device fillers to minimize or prevent this degradation. Two of these HTPs have shown good thermal stability in the 400-500°C temperature range. The coatings were initially applied to bismuth telluride (Bi 2 Te 3 )-based TE materials that are used for commercial power generation devices specified for operation up to 250°C. The HTPs protect the Bi 2 Te 3 from both weight loss and weight gain up to 500°C. This is clearly outside the optimum TE operation range of Bi 2 Te 3 materials, but demonstrates the ability of the HTP coatings to protect the Bi 2 Te 3 materials at least up to 250°C. The properties that HTP materials demonstrated during the examination of suitability of their use for TE element coatings and/or TE device fillers using Bi 2 Te 3 are expected to hold good for higher operating temperature TE materials also

Hydroxyapatite based hybrid dental materials with controlled porosity and improved tribological and mechanical properties

Hybrid dental materials were designed with controlled porosity and improved tribological and mechanical properties. These materials are based on hydroxyapatite (HAp) and reinforced with two different types of ceramic particles, alumina and silica, to support the high stresses and the continuous scratching produced during mastication. The agglutinant phase is an alkyd polyester polyurethane with high abrasion resistance that adheres well to surfaces containing OH groups. Porosity of the materials was controlled using sodium acetate powder of specified particle size as a pore former, thereby providing the materials with a morphology that resembles real teeth. The composition, structure and morphology were evaluated through several analytical techniques; results of scanning electron microscopy, dynamic light scattering, Fourier transform infrared spectroscopy, X-ray diffraction, induced coupled plasma optical emission spectroscopy and densitometry are reported. The ceramic powders incorporated (HAp, alumina and silica) were a combination of micro-and nanoscale particles; this use of different sized particles improved the packing and consequently the mechanical and tribological properties of the dental materials. Tribological features are explained from results of microscratch testing and abrasion resistance. The elastic modulus from mechanical testing is compared for the entire set of hybrid dental composites developed

Composites Containing Bamboo With Different Binders

This paper discusses the formation of primary chemical bonds between bamboo surface active groups and the binders

Re-establishing glacier monitoring in Kyrgyzstan and Uzbekistan, Central Asia

Glacier mass loss is among the clearest indicators of atmospheric warming. The observation of these changes is one of the major objectives of the international climate monitoring strategy developed by the Global Climate Observing System (GCOS). Long-term glacier mass balance measurements are furthermore the basis for calibrating and validating models simulating future runoff of glacierised catchments. This is essential for Central Asia, which is one of the driest continental regions of the Northern Hemisphere. In the highly populated regions, water shortage due to decreased glacierisation potentially leads to pronounced political instability, drastic ecological changes and endangered food security. As a consequence of the collapse of the former Soviet Union, however, many valuable glacier monitoring sites in the Tien Shan and Pamir Mountains were abandoned. In recent years, multinational actors have re-established a set of important in situ measuring sites to continue the invaluable long-term data series. This paper introduces the applied monitoring strategy for selected glaciers in the Kyrgyz and Uzbek Tien Shan and Pamir, highlights the existing and the new measurements on these glaciers, and presents an example for how the old and new data can be combined to establish multi-decadal mass balance time series. This is crucial for understanding the impact of climate change on glaciers in this region

Transplantation of canine olfactory ensheathing cells producing chondroitinase ABC promotes chondroitin sulphate proteoglycan digestion and axonal sprouting following spinal cord injury

Olfactory ensheathing cell (OEC) transplantation is a promising strategy for treating spinal cord injury (SCI), as has been demonstrated in experimental SCI models and naturally occurring SCI in dogs. However, the presence of chondroitin sulphate proteoglycans within the extracellular matrix of the glial scar can inhibit efficient axonal repair and limit the therapeutic potential of OECs. Here we have used lentiviral vectors to genetically modify canine OECs to continuously deliver mammalian chondroitinase ABC at the lesion site in order to degrade the inhibitory chondroitin sulphate proteoglycans in a rodent model of spinal cord injury. We demonstrate that these chondroitinase producing canine OECs survived at 4 weeks following transplantation into the spinal cord lesion and effectively digested chondroitin sulphate proteoglycans at the site of injury. There was evidence of sprouting within the corticospinal tract rostral to the lesion and an increase in the number of corticospinal axons caudal to the lesion, suggestive of axonal regeneration. Our results indicate that delivery of the chondroitinase enzyme can be achieved with the genetically modified OECs to increase axon growth following SCI. The combination of these two promising approaches is a potential strategy for promoting neural regeneration following SCI in veterinary practice and human patients