Designing antimicrobial surfaces for dental applications

Ansätze für die Entwicklung selektiv wirkender bakterizider Beschichtungen, die eine Biofilmbildung auf Implantatoberflächen mit Hautdurchtrittsregion verhindern und sich durch eine für die klinische Praxis zufrieden stellende Biokompatibilität auszeichnen, wurden untersucht. Dabei wurde die Fähigkeit von amphiphilen Polymeren zur Schädigung bakterieller Zellmembran sowie die antiseptische Wirksamkeit von Silberionen bei gleichzeitig geringer Toxizität genutzt. Ein möglicher Lösungsansatz beinhaltete die Verwendung von 4-Vinyl-N-hexyl-pyridiniumbromid als antimikrobiell aktive und das Phosphonat Dimethyl(2-methacryloyloxyethyl)phosphonat als oberflächenaktive Komponente. Durch freie radikalische Copolymerisation gelang zunächst die Synthese von Vinylpyridin-haltigen Präpolymeren mit definierten Abstufungen in der Zusammensetzung. Durch polymeranaloge Umsetzung im Rahmen einer N-Alkylierungsreaktion erfolgte die Einführung antimikrobiell aktiver quartärer Ammoniumgruppen. In Abhängigkeit des Beschichtungsmaterials wurden Ausmaß der N-Alkylierung und eingesetztes N-Alkylierungsreagenz variiert. In als Matrices für Kompositmaterialien dienende Copolymere konnte in einem weiteren Schritt durch in-situ Fällungsreaktion die Einlagerung von Silberbromid-Nanopartikeln erreicht werden. Die Anbindung der phosphonathaltigen Polymere und Komposite an Titan(oxid) in Form von ultradünnen Filmen konnte aufgrund ihrer Oberflächenaktivität in einem einfachen Spin Coating-Prozess mit anschließendem Tempern erzielt werden. Die Evaluierung der antimikrobiellen Wirksamkeit der modifizierten Oberflächen und die Evaluierung der Kompatibilität gegenüber humanen Gingivafibroblasten identifizierten die Polymerbeschichtung mit einer Zusammensetzung von (hexyl VP)0.24-co-(DMMEP)0.76 als am besten für die zahnmedizinische Anwendung geeignet. Es wurde ein signifikant antimikrobieller Effekt bei gleichzeitig akzeptabler Biokompatibilität erzielt.Approaches for the development of selective antimicrobial coatings that suppress biofilm formation on implant surfaces passing through human skin and showing sufficient biocompatibility for clinical application were investigated. Therefore the ability of amphiphillic polymers to damage bacterial cell membrane as well as the antiseptic action of silver ions exhibiting low toxicity at the same time was utilized. A possible route comprised the use of 4-vinyl-N-hexylpyridinium bromide exhibiting antimicrobial action and the use of the phosphonate dimethyl 2-methacryloyloxyethyl phosphonate being surface active. Initially synthesis of vinylpyridine based prepolymers by free radical copolymerization showing distinct variation in copolymer composition was achived. Introduction of quarternary ammonium groups showing antimicrobial action was carried out by polymer-analogous reaction in terms of N-alkylation. Depending on the coating material the extend of N-alkylation as well as the N-alkylating reagent applied were varried. In a next step incorporation of silver bromide nanoparticles into polymers serving as matrices for composite materials was achieved via in-situ precipitation reaction. Binding of phophonate containing polymers and composites onto titanium oxide surfaces by formation of ultrathin films could be achieved in a simple spin coating process followed by annealing taking advantage of the surface activity of phophonates. Evaluation of antimicrobial activity of modified surfaces and evaluation of compatibility with human gingival fibroblasts revealed a polymer coating consisting of hexyl VP0.24-co-DMMEP 0.76 as being most suitable for dental application. Significant antimicrobial effect and sufficient biocompatibility could be realized at the same time

Relationship Between Muscle Strength, Power and Stiffness and Running Economy in Trained Male Runners

Purpose: In this study, a comparison was made between muscle strength, power and muscle and tendon (k(m), and k(t) respectively) stiffness of the triceps surae muscle group and running economy (RE) in trained male runners. Methods: Twelve well-trained male runners (age = 21 +/- 2.7 y, height = 178.1 +/- 7.1 cm, body mass = 66.7 +/- 3.2 kg, VO(2)max = 68.3 +/- 4.3 mL.kg(-1).min(-1), 5000-m time = 15:04 min:s) undement passive stiffness testing using a free oscillation method. Muscle strength was determined via a maximal isometric squat test and power determined via a maximal countermovement jump (CMJ). On a separate day, subjects performed an incremental treadmill test and their RE, lactate threshold, and VO(2)max were determined. Fingertip blood lactate was determined at the end of each 3-min stage. Lactate threshold was defined as a nonlinear increase in lactate accumulation. Results: A statistically significant correlation was found between k(m) and VO(2) at stage 6 (r = 0.69, P = .01). In addition, statistically significant correlations were observed between CMJ peak force production and VO(2) at stage 2 (r = .66, P = .02), stage 3 (r = .70, P = .01), and stage 4 (r = .58, P = .04). No other statistically significant correlations were observed. Conclusion: These data suggest that greater muscle stiffness and less power are associated with greater RE. Future study in this area should focus on determining the mechanisms behind this relationship and how to best apply them to a running population through training techniques

Registration of serial sections: An evaluation method based on distortions of the ground truths

Registration of histological serial sections is a challenging task. Serial sections exhibit distortions and damage from sectioning. Missing information on how the tissue looked before cutting makes a realistic validation of 2D registrations extremely difficult. This work proposes methods for ground-truth-based evaluation of registrations. Firstly, we present a methodology to generate test data for registrations. We distort an innately registered image stack in the manner similar to the cutting distortion of serial sections. Test cases are generated from existing 3D data sets, thus the ground truth is known. Secondly, our test case generation premises evaluation of the registrations with known ground truths. Our methodology for such an evaluation technique distinguishes this work from other approaches. Both under- and over-registration become evident in our evaluations. We also survey existing validation efforts. We present a full-series evaluation across six different registration methods applied to our distorted 3D data sets of animal lungs. Our distorted and ground truth data sets are made publicly available.Comment: Supplemental data available under https://zenodo.org/record/428244

Late prehistoric bone marrow extraction : a case study in western Wisconsin

The Swennes Upper Garden Terrace site (47Lc333) in La Crosse County, Wisconsin has been the location of multiple excavations by the Mississippi Valley Archaeology Center at the University of Wisconsin-La Crosse since 1995. Of the many late prehistoric Oneota pit-features discovered at the site, Feature 30 was found to contain several hundred white-tailed deer (Odocoileus virginianus) bone fragments. These bones displayed characteristics indicating they had been systematically fractured in the production of "bone grease." Bone grease is obtained by boiling the fatty bone marrow out of the cancellous tissue of bones and is high in nutrients. Its production and use is documented ethnographically and archaeologically in various regions and climates. This paper examines the bone fragments from Feature 30 through quantitative analysis and the use of ethnographic, archaeological, and experimental literature, with the goal of interpreting the human processes resulting in their deposition within the feature

THE TERATOLOGIC EFFECTS OF N-ETHYL-N-NITROSOUREA ON THE DEVELOPMENT OF THE CEREBELLAR CORTEX OF THE RAT.

Abstract not availabl