247 research outputs found
Behavioural Cost Minimisation and Minimal Invasive Blood-Sampling in Meerkats (S. suricatta, Herpestidae)
Meerkats (S. suricatta) are social mongooses inhabiting semiarid habitats in southern Africa. They are physiologically desert-adapted, but also utilise a high proportion of behavioural thermoregulation. This study investigated how thermoregulation by behaviour can aid to minimise the physiological costs of thermoregulation. In a first part, behavioural observations derived from 230 observation hours at the �Kalahari Meerkat Project� in South Africa were correlated to ambient factors such as temperature, radiation, humidity and wind speed. It could be shown that temperature had the most significant influence on the distribution of the behavioural data. Especially the meerkats' upper and lower critical temperatures, literature data obtained in the lab, could aid at explaining the proportions of time spent in sun, shadow and below, as well as the proportion of times spent with thermoregulatory behaviours (contact lying, sunbathing and piloerection). The influence of radiation added on the effect of temperature, as the animals utilised solar radiation to heat up at low ambient temperatures (TA) and avoided it at high TA. Influences of humidity and wind speed were of minor importance. It is evident, that meerkats utilise a high proportion of behaviour to minimise energetic costs. Extrapolating from physiological literature data, it can be assumed that this minimization can amount up to 18% by a single behaviour. In a second part, a minimal invasive method of blood sampling was presented for zoo animals, also suitable for wild animals. For the fist time, this study could sample blood using tsetse G. brevipalpis in zoo animals on an outside enclosure. Insects were attached to the zoo animals in a box on a collar. These blood samples could be used to obtain data on energy expenditure with the �Doubly-Labelled -Water� (DLW) method and data on hormone levels. In contrast to previous works, study animals were not restricted in their mobility and could move freely during the blood sampling period. As insects were attached to the meerkats with a box, this technique allowed to derive blood samples at defined points of time, although the use may be limited to species habituated to close human presence. For the first time, this thesis presents a dipteran species that can be used as a tool for minimally invasive blood sampling, unlike previous works, that have been working with South American reduviid species. When planning to work in a South American environment, it was shown that these commonly used reduviids can easily be sterilized with ionising radiation to minimise potential risks to the environment. It could be presented that not only reduviids posses beneficial properties as blood-sampling tools, but except for the obtained blood volumes, tsetse seem to be even more applicable as they were more reliable (in terms of feeding motivation) and less temperature-sensitive, both important criteria when working in the field. Introducing a so far unimplemented, African blood parasitic species to obtain minimal invasive blood samples, a long term goal derived from this work could be to find suitable insect candidates in every environment where field studies could benefit from minimally invasive blood sampling
The liberalization of Austria's mail market
Nach drei EU-Richtlinien zur Liberalisierung des Postmarktes, musste Österreich einen liberalen Briefmarkt zulassen. Die vorgeschriebenen Änderungen werden dabei jedoch auf verschiedenste Weise implementiert. Muss man sich zwischen starker staatlicher Marktregulierung und wirklichen Freiheiten für das Unternehmertum entscheiden, scheint vielen Ländern Erstgenanntes wichtiger zu sein. Die Motive dafür mögen ethisch sein, vielleicht sind sie es auch nicht. Die Wirtschaftswissenschaft lässt jedenfalls die Ansammlung staatlicher Macht über scheinbar freie Märkte erkennen, indem sie uns lehrt, dass höchste Ausmaße von Effizienz und Wohlstand aus minimalistischer Markteinmischung folgen, nicht aus Richtlinien zu zahlreichen Themen, die den Markt betreffen. Doch da Politiker ökonomischen Ratschlägen nur begrenzt Gehör schenken, ist es noch ein langer Weg bis der Markt nicht mehr von einer oder wenigen Firmen mit signifikanter Marktmacht dominiert wird, deren starke Position die Entwicklung anderer Unternehmen hemmt und dadurch einem Absinken des Endverbraucherpreisniveaus im Wege steht.After three EU directives aiming at full liberalization of the postal market, Austria finally had to give way to a liberal mail market. However, the paths to implementation of the prescribed changes are manifold. When faced with the decision between strong market regulation by governments or truly allowing free enterprise, most countries seem to opt for the former. The motives might be ethical, or maybe they aren’t. In any case, economic science betrays the amassing of government powers over supposedly liberal markets by teaching us that highest efficiency and welfare come from minimalistic market intervention, as opposed to regulations about any number of topics with regard to the market’s business. But since politicians will not extensively heed economic advice, it will be a long time until the market seizes to include one or a few firms with significant market power, whose strong positions inhibit the development of other companies and, therefore, get in the way of lower consumer prices
Image segmentation by graph partitioning
In this paper we propose an hybrid method for the image segmentation which combines the edge-based, region-based and the morphological techniques in conjunction through the spectral based clustering approach. An initial partitioning of the image into atomic regions is set by applying a watershed method to the image gradient magnitude. This initial partition is the input to a computationally efficient region segmentation process which produces the final segmentation. We have applied our approach on several images of the Berkeley Segmentation Dataset. The results reveal the accuracy of the propose method
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Polymer-based controlled-release fed-batch microtiter plate - diminishing the gap between early process development and production conditions
Background: Fed-batch conditions are advantageous for industrial cultivations as they avoid unfavorable phenomena appearing in batch cultivations. Those are for example the formation of overflow metabolites, catabolite repression, oxygen limitation or inhibition due to elevated osmotic concentrations. For both, the early bioprocess development and the optimization of existing bioprocesses, small-scale reaction vessels are applied to ensure high throughput, low costs and prompt results. However, most conventional small-scale procedures work in batch operation mode, which stands in contrast to fed-batch conditions in large-scale bioprocesses. Extensive expenditure for installations and operation accompany almost all cultivation systems in the market allowing fed-batch conditions in small-scale. An alternative, more cost efficient enzymatic glucose release system is strongly influenced by environmental conditions. To overcome these issues, this study investigates a polymer-based fed-batch system for controlled substrate release in microtiter plates. Results: Immobilizing a solid silicone matrix with embedded glucose crystals at the bottom of each well of a microtiter plate is a suitable technique for implementing fed-batch conditions in microtiter plates. The results showed that the glucose release rate depends on the osmotic concentration, the pH and the temperature of the medium. Moreover, the applied nitrogen source proved to influence the glucose release rate. A new developed mathematical tool predicts the glucose release for various media conditions. The two model organisms E. coli and H. polymorpha were cultivated in the fed-batch microtiter plate to investigate the general applicability for microbial systems. Online monitoring of the oxygen transfer rate and offline analysis of substrate, product, biomass and pH confirmed that fed-batch conditions are comparable to large-scale cultivations. Furthermore, due to fed-batch conditions in microtiter plates, product formation could be enhanced by the factor 245 compared to batch cultivations. Conclusions: The polymer-based fed-batch microtiter plate represents a sophisticated and cost efficient system to mimic typical industrial fed-batch conditions in small-scale. Thus, a more reliable strain screening and early process development can be performed. A systematical scale-down with low expenditure of work, time and money is possible. © 2019 The Author(s)
Phosphorus macrocycles and cryptands
The reviews covers authors" studies dealing with the synthesis of PIII- and PV-containing macrocycles and cryptands. The separation, structural characterization, and the chemical properties of a number of homeomorphic compounds with in,out bridgehead phosphorus atoms are described. Modification of the in-positions in macrobicyclic compounds with bulky groups is described for the first time
Comparison of the non-invasive Nexfin® monitor with conventional methods for the measurement of arterial blood pressure in moderate risk orthopaedic surgery patients
Objective Continuous invasive arterial blood pressure (IBP) monitoring remains
the gold standard for BP measurement, but traditional oscillometric non-
invasive intermittent pressure (NIBP) measurement is used in most low-to-
moderate risk procedures. This study compared non-invasive continuous arterial
BP measurement using a Nexfin® monitor with NIBP and IBP monitors. Methods
This was a single-centre, prospective, pilot study in patients scheduled for
elective orthopaedic surgery. Systolic BP, diastolic BP and mean arterial
blood pressure (MAP) were measured by Nexfin®, IBP and NIBP at five
intraoperative time-points. Pearson correlation coefficients, Bland–Altman
plots and trending ability of Nexfin® measurements were used as criteria for
success in the investigation of measurement reliability. Results A total of 20
patients were enrolled in the study. For MAP, there was a sufficient
correlation between IBP/Nexfin® (Pearson = 0.75), which was better than the
correlation between IBP/NIBP (Pearson = 0.70). Bland–Altman analysis of the
data showed that compared with IBP, there was a higher percentage error for
MAPNIBP (30%) compared with MAPNexfin® (27%). Nexfin® and NIBP underestimated
systolic BP; NIBP also underestimated diastolic BP and MAP. Trending ability
for MAPNexfin® and MAPNIBP were comparable to IBP. Conclusion Non-invasive BP
measurement with Nexfin® was comparable with IBP and tended to be more precise
than NIBP
Phosphorus-containing calixarenes
Data on the synthesis, conformational behaviour and complexing properties of calix[4]resorcinolarene and calix[n]arene derivatives modified by phosphorus-containing fragments are surveyed. © 1998 Russian Academy of Sciences and Turpion Ltd
Biomimetic cooperative interactions of dried cross-linked poly(N-6-aminohexylacrylamide) with binary mixtures of solvent vapors
Biomimetic cooperativity of hydration effect and effect of ethanol favorable for binding of bad organic sorbates were observed for their vapor sorption by cross-linked poly(N-6-aminohexylacrylamide) (PNAHAA) in the absence of liquid phase. The vapor sorption isotherms were determined for these systems by the static method of gas chromatographic headspace analysis at 298 K The hydration above 0.09-0.13 g of H2O/(g of polymer) gives a cooperative increase in the PNAHAA binding affinity for benzene, cyclohexane, dioxane, and propanols up to a level which does not change by further hydration, indicating the polymer antiplasticization. Bad sorbates (dioxane, benzene) were observed to have a biomimetic cooperative influence on the binding of ethanol by the dried PNAHAA. This cooperativity does not occur in ternary systems with good norhydroxylic sorbate acetonitrile. © 2004 American Chemical Society
Human white adipose tissue vasculature contains endothelial colony-forming cells with robust in vivo vasculogenic potential
Epub ahead of print.-- The final publication is available at link.springer.comBlood-derived endothelial colony-forming cells (ECFCs) have robust vasculogenic potential that
can be exploited to bioengineer long-lasting human vascular networks in vivo. However,
circulating ECFCs are exceedingly rare in adult peripheral blood. Because the mechanism by
which ECFCs are mobilized into circulation is currently unknown, the reliability of peripheral
blood as a clinical source of ECFCs remains a concern. Thus, there is a need to find alternative
sources of autologous ECFCs. Here we aimed to determine whether ECFCs reside in the
vasculature of human white adipose tissue (WAT) and to evaluate if WAT-derived ECFCs
(watECFCs) have equal clinical potential to blood-derived ECFCs. We isolated the complete
endothelial cell (EC) population from intact biopsies of normal human subcutaneous WAT by
enzymatic digestion and selection of CD31+ cells. Subsequently, we extensively compared
WAT-derived EC phenotype and functionality to bonafide ECFCs derived from both umbilical
cord blood and adult peripheral blood. We demonstrated that human WAT is indeed a
dependable source of ECFCs with indistinguishable properties to adult peripheral blood ECFCs,
including hierarchical clonogenic ability, large expansion potential, stable endothelial phenotype,
and robust in vivo blood vessel-forming capacity. Considering the unreliability and low rate of
occurrence of ECFCs in adult blood and that biopsies of WAT can be obtained with minimal
intervention in an ambulatory setting, our results indicate WAT as a more practical alternative to
obtain large amounts of readily available autologous ECFCs for future vascular cell therapies.This work was supported by a
National Institutes of Health Grant (R00EB009096, J. M.-M).Peer reviewe
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