Temperature-dependent morphology changes of noble metal tricalcium phosphate-nanocomposites

Calcium phosphates, functionalized with nano-sized metal particles, are a promising material class for the treatment of bone defects. However, a sintering process is required in principle to achieve sufficient strength of calcium phosphate scaffolds. In this work laser-generated nano-sized silver, gold and platinum particles were adsorbed on micro-sized β-tricalcium phosphate particles and further heat treated at temperatures between 600 and 1200 °C. Gold and platinum nanoparticles underwent exponential growth starting at about 600 °C, while sintering of β-tricalcium phosphate started at 800 °C. We hypothesise that this phenomenon is caused by a heat-induced evaporation and growth process where the decrease of the particle number is directly correlated with the size increase. The silver nanoparticles on the other hand formed a new phase with the calcium phosphate (AgCa₁₀(PO₄)₇) during the heat treatments and could not be observed within the ceramic scaffold anymore. Addressing the lack of information in nanoparticle-combined calcium phosphate scaffolds, this study contributes to the further modification of bone replacement materials with biologically relevant functions and molecules.     

ATRP-based synthesis and characterization of light-responsive coatings for transdermal delivery systems

The grafting of poly(hydroxyethylmethacrylate) on polymeric porous membranes via atom transfer radical polymerization (ATRP) and subsequent modification with a photo-responsive spiropyran derivative is described. This method leads to photo-responsive membranes with desirable properties such as light-controlled permeability changes, exceptional photo-stability and repeatability of the photo-responsive switching. Conventional track etched polyester membranes were first treated with plasma polymer coating introducing anchoring groups, which allowed the attachment of ATRP-initiator molecules on the membrane surface. Surface initiated ARGET–ATRP of hydroxyethylmethacrylate (where ARGET stands for activator regenerated by electron transfer) leads to a membrane covered with a polymer layer, whereas the controlled polymerization procedure allows good control over the thickness of the polymer layer in respect to the polymerization conditions. Therefore, the final permeability of the membranes could be tailored by choice of pore diameter of the initial membranes, applied monomer concentration or polymerization time. Moreover a remarkable switch in permeability (more than 1000%) upon irradiation with UV-light could be achieved. These properties enable possible applications in the field of transdermal drug delivery, filtration, or sensing.     

Effects of chronic environmental cold on growth, health, and select metabolic and immunologic responses of preruminant calves

The physiological response of the preruminant calf to sustained exposure to moderate cold has not been studied extensively. Effects of cold on growth performance and health of preruminant calves as well as functional measures of energy metabolism, fat-soluble vitamin, and immune responsiveness were evaluated in the present study. Calves, 3 to 10 d of age, were assigned randomly to cold (n = 14) or warm (n = 15) indoor environments. Temperatures in the cold environment averaged 4.7°C during the study. Frequent wetting of the environment and the calves was used to augment effects of the cold environment. Temperatures in the warm environment averaged 15.5°C during the study. There was no attempt to increase the humidity in the warm environment. Preventative medications or vaccinations that might influence disease resistance were not administered. Nonmedicated milk replacer (20% crude protein and 20% fat fed at 0.45 kg/d) and a nonmedicated starter grain fed ad libitum were fed to all calves. Relative humidity was, on average, almost 10% higher in the cold environment. Warm-environment calves were moderately healthier (i.e., lower respiratory scores) and required less antibiotics. Scour scores, days scouring, and electrolyte costs, however, were unaffected by environmental temperature. Growth rates were comparable in warm and cold environments, although cold-environment calves consumed more starter grain and had lower blood glucose and higher blood nonesterified fatty acid concentrations. The nonesterified fatty acid and glucose values for cold-stressed calves, however, did not differ sufficiently from normal values to categorize these calves as being in a state of negative-energy balance. Levels of fat-soluble vitamin, antibody, tumor necrosis factor-α, and haptoglobin were unaffected by sustained exposure to moderate cold. These results support the contention that successful adaptation of the dairy calf to cold is dependent upon the availability of adequate nutrition.     

Thermomechanical Fatigue Behavior of the Intermetallic <Emphasis Type="Italic">γ</Emphasis>-TiAl Alloy TNB-V5 with Different Microstructures

The cyclic deformation and fatigue behavior of the γ-TiAl alloy TNB-V5 is evaluated under thermomechanical load for three different microstructures. For this purpose, strain-controlled thermomechanical fatigue (TMF) tests were carried out with different temperature-strain cycles, different temperature ranges from 400 °C to 800 °C (673 K to 1073 K), and with two different strain ranges to set a fatigue-life relation. Cyclic deformation curves, stress-strain hysteresis loops, and fatigue lives of the tests are presented. The microstructures near-gamma (NG) and duplex (DP) show comparable fatigue lives under all test parameters. The microstructure fully-lamellar (FL) offers longer fatigue lives at the same loading conditions. For a general life prediction, the damage parameter of Smith, Watson, and Topper, P _SWT vs fatigue life, is well suitable, if the testing and the application temperature ranges, respectively, include temperatures above the ductile-brittle transition (approximately 750 °C). In the completely brittle material behavior regime the quality of the lifetime prediction is unacceptable. The damage parameter P _HL by Haibach and Lehrke shows a comparable correlation to the fatigue life as P _SWT. The results are discussed with microstructural investigations.     

TeraPro, a system for processing large biomedical images

Image analysis plays an important role both in medical diagnostics and in biology. The main reasons that prevent the creation of objective and reliable methods of analysis of biomedical images are the high variability and heterogeneity of the biological material, distortion introduced by the experimental procedures, and the large size of the images. This paper presents preliminary results on creating a system called Ter-aPro, which combines a platform for image processing (ProStack) and a raster data storage system (rasdaman). This integrated system can be used in a cloud environment, providing access to the methods of visualization, analysis, and processing of a large amount of images through the Internet. Such an approach increases the speed and quality of image understanding and softens the limitations imposed by other systems. The system allows us to view uploaded images in the browser without having to install additional software on any device connected to the Internet, such as tablet computers and smartphones. This paper presents the preliminary results of processing biomedical images.     

Practical considerations in the optimization of flow production systems

In this paper we consider the problems faced by an industrial planner who is responsible for the design of real-life asynchronous production lines under stochastic conditions that may be due to breakdowns or random processing times. Based on real-life system data, it is shown that a number of available algorithms for the performance evaluation of a given system configuration as well as an algorithm for determining the optimum buffer configuration can be successfully applied in industrial practice.     

Disruptive innovations: The case for hydrogen fuel cells and battery electric vehicles

The investment of private money in technological innovation is driven by the expectation of successful market penetration. This decision to invest is less risky when the innovation represents gradual improvement of existing technologies. The term disruptive innovation is used to describe the opposite case, i.e. innovations that are so different that their establishment in the market causes a disruption to the pre-existing system. The existing literature on disruptive innovations provides us with historic case studies of successful market capture by new technologies, but this in itself is insufficient to clarify the chances of success for nascent technologies. This paper sets out to bring greater clarity to the characteristics of disruptive innovation in a way that informs the debate on the viability of emerging technologies. Whilst existing definitions are based on technologies that were successful, this paper proposes a three part criteria to define candidate disruptive technologies: disruption should relate to manufacturers and/or infrastructure (the two often being inter-related), whilst innovation must provide more than the equivalence of service to the end-user. A review of seven historical case studies of successful disruptive technologies reveals seven characteristics of candidate disruptive technologies at the stage of niche market penetration. Examining battery electric and hydrogen fuel cell vehicles against these seven characteristics, shows that both candidate disruptive technologies share the same challenges as those identified in the successful historic case studies and also helps to identify potential pathways to greater market penetration in the future for these technologies.     

Mode of drug binding to DNA determined by optical tweezers force spectroscopy

Abstract

Optical tweezers were employed to investigate the effects of small DNA-binding molecules on the low-force (≤ 15 pN) stretching behaviour of single DNA molecules. As the canonical B-DNA helix is not perturbed in this force regime, the effects on DNA elasticity observed upon drug binding provide useful insight into how DNA-binding drugs may alter in vivo processes. In this study, the effects of agents with different DNA binding modes were analysed. DNA force—extension curves were recorded in the presence of netropsin, a purely minor groove-binding antibiotic drug, ethidium bromide, an intercalating fluorescent dye, and berenil, an antiprotozoal drug proposed to exhibit both intercalative and minor groove-binding modes. Applying an approximation of the worm-like chain model, which describes the low-force stretching behaviour, the results were analysed in terms of the DNA contour length and persistence length. From these single molecule studies it was observed that minor groove-binding and intercalating modes of DNA-binding could be distinguished based on changes to DNA elasticity.     

Spatial distribution of dental fluorosis in roe deer (Capreolus capreolus) from North Bohemia (Czech Republic) and its relationships with environmental factors

We assessed the spatial variation of fluoride load on the local ecosystem in the Czech part of the Ore Mountains region and its southern foothills - a heavily polluted part of Europe's "Black Triangle" region. Dental fluorosis in roe deer (Capreolus capreolus) served as a biomarker of fluoride exposure and thus as an indicator of environmental pollution by fluoride. The mean dental lesion index of fluorosis (DLI) calculated from the analyzed mandibles of wild roe deer (>or=2 years of age) was assigned to the hunting ground from which the specimens originated and classified into one of the eight fluorosis categories. Environmental factors potentially related to dental fluorosis (atmospheric deposition of sulfur, concentration of fluoride in and pH of surface waters, geomorphologic features, bedrock and soil type, and vegetation cover), which were represented in the study by GIS layers, were examined to explain the distribution pattern and severity of fluorosis in the roe deer. The study revealed that 75.5% of 616 analyzed mandibles showed dental fluorosis to different extent, with individual DLIs ranging from 0 to 21. The spatial pattern of marked fluorosis on the Czech side continues that found in a previous study on the German side of the Ore Mountains. Together they create a landscape island around several thermal power plants in the region. General Linear Model (GLM) analyses revealed significant relationships between degree of forest damage, soil type, and atmospheric sulfur deposition from air pollution and dental fluorosis, expressed as mean DLI in the roe deer.