Search Results - (Author, Cooperation:M. Behr)

2018-07-27

American Chemical Society (ACS)

0006-2960

1520-4995

Biology

Chemistry and Pharmacology

2012-08-04

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Animals ; Antibodies, Viral/blood ; Cytokines/genetics/*immunology ; Female ; Granulocytes/immunology ; Humans ; Immunity ; Interferon-gamma/*immunology ; Interleukin-12/immunology ; Killer Cells, Natural/immunology ; Male ; Mice ; Mycobacterium Infections/blood/genetics/*immunology ; Pedigree ; T-Lymphocytes/immunology ; Ubiquitins/genetics/*immunology ; Virus Diseases/blood/*immunology

2016-04-23

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Animals ; Gastrointestinal Tract/immunology ; *Gene Expression Regulation ; Genes, Regulator/genetics/*physiology ; Immunologic Memory/*genetics ; Kidney/immunology ; Killer Cells, Natural/*immunology ; Liver/immunology ; Lymphocyte Activation ; Mice ; Mice, Knockout ; Natural Killer T-Cells/*immunology ; Skin/immunology ; Transcription Factors/genetics/*physiology ; Transcription, Genetic ; Up-Regulation

1365-2842

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Summary  The aim of this in vitro study was to compare the fracture strength of three-unit FPDs (fixed partial dentures) and three-unit inlay FPDs after a simulated 5-year oral wearing period. The restorations were made of a pressable all-ceramic (Empress 2) and two specially designed, experimentally fixed partial dentures combining ceramics with dental composite. Three-unit FPDs and inlay FPDs were manufactured and were adhesively luted onto human molars. After thermal cycling and mechanical loading in an artificial environment, the fracture strength was determined. Zircon-based milled ceramic (Lava) three-unit FPDs were used as a control. The zircon ceramic and the fibre-based ceramic three-unit FPDs showed median fracture values between 1000 and 1400 N. For composite veneered zircon FPDs a fracture strength of about 800 N and for all-ceramic Empress 2 of about 350 N could be determined. The results for the inlay FPDs were between 1300 N and 1400 N for FRC/ceramic, 1000 N for zircon/composite and 500 N for all-ceramic restorations. The all-ceramic showed higher fracture resistance applied as inlay FPDs. The described hybrid techniques combining ceramics and composites could represent an interesting procedure for further investigations and, eventually, clinical implication.

Electronic Resource

1365-2842

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

This in vitro study was carried out in order to estimate the clinical usability of adhesively luted three-unit posterior fixed partial dentures (FPD) made of a polyethylene-fibre-reinforced-composite system (PFRC) in comparison with a glass-fibre-reinforced-composite system (GFRC). Therefore the fracture strength and marginal adaptation were examined. A total of 16 FPDs of each material combination were manufactured and adhesively luted to human molars. Before and after an artificial ageing process by thermal cycling and mechanical loading (TCML) the quality of the marginal adaptation was examined by evaluating epoxy replicas in a scanning electron microscope (SEM). After TCML the fracture strength of eight FPDs of each series was tested by mechanical loading them to failure. With the remaining eight FPDs the quality of deeper layers of the luting was examined with a dye penetration technique. The calculated median fracture strength values (25/75% percentiles) were 830 N (643/982) for the PFRC and 884 N (684/1113) for the GFRC. The SEM analysis showed at least 80% of perfect marginal areas for both material combinations in dentine as well as in enamel before and after TCML. Looking at the cement–tooth interfaces the dye penetration technique showed statistically significant better results for the enamel finishing lines than for those in dentine. With finishing lines in dentine the two material combinations showed statistically significant differences for this interface. Fracture force results as well as marginal quality encourage further clinical investigations on both systems although the GFRC performed slightly better than the PFRC.

Electronic Resource

1365-2842

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

The aim of the study was to check four lab-side and four chair-side methods for finishing and polishing the ceromer material Targis®. Eighty bar-shaped specimens (20 mm × 10 mm × 2 mm) of Vectris were produced; 72 were covered with a 2 mm (thickness) layer of the Ceromer Targis® and eight samples with the composite Tetric®. All specimens were ground plane parallel with 320 Silicium carbide grit sandpaper in order to start with the same level of roughness. Then the specimens were finished and polished using the following methods: (1) Artglass® toolkit, (2) pumice-stone and brushes/linen brush and polishing paste P3, (3) Robinson® brush/Ivoclar Universal® paste and wool brush, (4) Silicone wheel and rag wheel, (5) Shofu Rainbow® set, (6) Sof-Lex® discs, (7) Vivadent Politip® set and (8) Nupro-pastes® and brushes. The surface roughness was determined with a profilometer. The arithmetical roughness value Ra was calculated. From each group one specimen was randomly chosen and sputtered with gold in order to observe the surface with a scanning electron microscope to evaluate its smoothness. The methods were ranked as followed: 2, 3 and 5 with the lowest roughness, then 8, 6, 7, 4, 1. The best ranked chair-side method (5) and the best ranked lab-side methods (2, 3) did not differ significantly between the Ra values. No difference was observed between the composite Tetric® and the ceromer Targis® when these materials were polished using the same method.Conclusion: the lab-side-methods 2 and 3 and the chair-side-method 5 can be recommended for finishing and polishing the new ceromer material Targis®.

Electronic Resource

1365-2842

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Fracture of porcelain fused to metal veneering may cause premature failure of fixed partial prosthodontics. Through the use of intra-oral composite bonded porcelain repair systems, the replacement of the prosthetic reconstruction can be avoided. The aim of this study was to evaluate the shear bond strength of porcelain repair systems currently in use and the effect of thermocycling and mechanical loading (TCML) on the adhesion of composite to ceramic surfaces in comparison with the composite to metal bonding system Rocatec®. Specimens were fabricated by fusing the veneering ceramic VMK-68® (Vita) to Co-Cr-Mo-alloy base plates. Twenty cylindrically shaped composite samples in each series were bonded to the porcelain surface using porcelain repair systems currently in use. The shear bond strength of 10 samples was evaluated after 24 h (baseline) and after loading in an artificial oral environment. The repair systems Z 100 Kit®, Monobond S/Tetric® and Porcelain Etch® were not impaired by TCML and exhibited a shear bond strength of greater than 12 MPa, which was comparable to the control group Rocatec®. The shear strength of the repair systems Silistor® and All-Bond® 2 decreased significantly after TCML. Using the appropriate repair system, the repair of ceramic-veneered fixed partial prosthodontics can be recommended as a medium term alternative to a new reconstruction.

Electronic Resource

1365-2842

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

summary  The aim of this in vitro study was to determine the thermal mechanical properties of veneering composites after polymerization with the appropriate polymerization device. Fracture tests were performed to investigate the effect on fixed partial dentures (FPDs).Dynamic mechanical thermal analysis was used to determine the temperature-dependent mechanical properties. To approximate the clinical situation, the fracture resistance of three-unit metal-based FPDs with different composite veneering was investigated after a simulated 5-year oral wearing period. The restorations were made of a high gold alloy and veneered with three different composites. To determine the influence of fabrication, one composite was used in a light-polymerizing and a heat/pressure-curing version and, in addition, a newly developed heat protection paste was used. After a 5-year simulation period, the fracture resistance was determined.The storage modulus varied between 14268 N mm−2 (Belleglass) and 6616 N mm−2 (Sinfony). Adoro showed no significant differences between light curing (9155 N mm−2) and heat curing (8184 N mm−2) variations. The Adoro-veneering with the heat protection paste showed the highest median fracture strength (1700 N), followed by Adoro LC (1555 N), Belleglass (1051 N), Adoro HP (1150 N) and Sinfony (909 N). The most common failure type occurring in all FPDs was a cracking of the composite, exposing the metal framework. All FPDs showed stress cracking of the composite. The heat protection paste seemed to reduce the crack formation after fabrication and increased the fracture resistance of the composite veneering. Stress cracking after thermal cycling and mechanical loading affected all composites, but all veneered three-unit alloy FPDs showed a fracture resistance sufficient for posterior application.

Electronic Resource

1365-2842

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

The objective was to investigate the fracture strength and marginal fit of implant suprastructures made of fibre-reinforced composite which were fixed onto the implants using cementation or screws. A sample (n=8) of 4-unit bridges, made of the fibre-reinforced composite Vectris/Targis, were adhesively cemented onto titanium conical implant abutments. The second sample consisted of eight screwable Vectris/Targis bridges which were based on prototypes of titanium crown bases. After a 5 year simulation of thermal cycling and mechanical loading (TCML), all specimen were loaded to fracture. Marginal fit was investigated using a semiquantitative SEM analysis. The cemented 4-unit bridges showed a fracture strength of 1553 N (Q1=1498 N, Q3=1825 N) and the screw-fixed bridges had a median of 1457 N (Q1=1223 N, Q3= 1781 N). The analysis of the marginal adaptation showed similar results of cemented and screwed bridges. The bond between the Targis facing-material and the composite cement was significantly deteriorated after TCML. Conclusion: Suprastructures made of glass–fibre-reinforced composite could become an alternative to reconstructions with a metal-framework. Both, fixation onto the implants with screws or cementation, are possible.

Electronic Resource

1365-2842

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

In root-treated anterior teeth a better aesthetic can be achieved by using translucent and tooth-coloured post and core restorations instead of traditional metal post systems. The aim of this in vitro study was to compare the fracture strength of tooth-coloured ceramic and fibre-reinforced posts as well as titanium posts with clinically proven gold alloy posts as a control. Two all-ceramic, one gold alloy and three combined post restoration systems (titanium and ceramic, respectively, fibre-reinforced posts with composite core) were each applied to upper incisors and after thermal cycling and mechanical loading (TCML) the fracture strength was determined. The variant providing the most reliable fracture strength values and the experimental fibre-reinforced composite (FRC) posts were – in combination with adhesively luted crowns – used to determine the fracture strength of the restoration after thermal cycling and mechanical loading. The median fracture strength of the luted posts and cores fluctuated between 114 and 546 N. Posts with composite cores demonstrate a higher fracture strength in comparison to the all-ceramic and gold alloy systems. Typical failure of metal systems was marked by loosening of the bonding and pulling out of the post in contrast to fracture of the ceramic posts. After the application of the crowns the ceramic system with composite core provided a fracture strength of 338 N and the FRC system a fracture strength of 228 N. Regarding fracture strength, the ceramic posts with composite cores are an alternative to commonly used gold posts and cores. A standardized technical manufacture of FRC posts and cores would provide better fracture strength results of this new dental material. Post and core restorations with tooth-coloured, translucent material offer an improved aesthetic especially in anterior restorations. Because of the high fracture strength prefabricated ceramic posts in combination with composite cores should prove their clinical applicability.

Electronic Resource

1365-2842

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

summary  The aim of this in vitro study was to compare the fracture resistance and marginal adaptation of all-ceramic incisor crowns with all-ceramic posts, glass–fibre-reinforced posts and titanium posts as well as a control without any post. Three groups of eight maxillary incisors were restored with an all-ceramic post, a fibre-reinforced composite (FRC) post, a titanium post and a further group was restored without posts. Composite cores were provided and all-ceramic crowns were adhesively luted. After artificial ageing, the fracture resistance of the restored teeth was determined. The marginal adaptation of the restorations at the interfaces between cement-tooth and cement-crown was evaluated with scanning electron microscopy using replica specimen before and after ageing. The restored teeth without posts [270N (235/335)] showed no significantly different fracture strength compared with teeth with the titanium system [340N (310/445)]. The all-ceramic posts [580N (425/820)] and the FRC posts [505N (500/610)] both provided a significant higher fracture resistance than the teeth without posts. Prior to ageing, all materials showed 〈5% separation at the margins cement-tooth or cement-crown (‘marginal gap’). After ageing, the interfaces of all systems deteriorated to values between 6 and 14% marginal gap. The greatest marginal gap was found with the titanium system (14%) at the interface cement-crown and with the all-ceramic posts (12%) at the transition between cement-tooth. Regarding fracture resistance and the marginal adaptation, the all-ceramic and FRC posts may be considered as an alternative to the commonly used titanium post restorations.

Electronic Resource

1365-2036

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Background : Helicobacter has been identified in isolated cases of hepato-biliary diseases, but its role in the pathogenesis of these conditions remains unclear.Aim : To determine whether Helicobacter could be detected in bile obtained at endoscopic retrograde cholangiopancreatography, and to evaluate the prevalence of this infection in patients with hepato-biliary diseases.Methods : Bile was collected from 125 patients with various hepato-biliary diseases undergoing endoscopic retrograde cholangiopancreatography. Among them, 75 were diagnosed with biliary stones, 15 with pancreatico-biliary malignancies and four with primary sclerosing cholangitis. The detection of Helicobacter in DNA extracted from these bile samples was performed using Helicobacter genus-specific primers (capable of detecting 100–1000 organisms/mL).Results : Helicobacter was detected in all positive controls. Only three samples had polymerase chain reaction inhibitors. All remaining bile samples (122 patients with hepato-biliary diseases) were negative for Helicobacter DNA.Conclusions : Helicobacter can be detected in bile samples using polymerase chain reaction. This infection, however, was not present in any of our patients diagnosed with gallstones or hepato-biliary malignancies, raising doubt as to the possible association between Helicobacter and these entities. Given the low sample size of patients with primary sclerosing cholangitis, more studies are required to determine whether an association exists with this condition.

Electronic Resource

0167-4781

Allele-specific amplification ; Autoimmunity ; Genetics ; Graves' disease ; Mutation ; Thyrotropin receptor

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Chemistry and Pharmacology

Medicine

Physics

Electronic Resource

0378-1119

Recombinant DNA ; amino acid sequence comparison ; archaea ; heterologous enzyme activity

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Electronic Resource

0303-7207

3T3-L1 cell ; Adipogenic differentiation ; Hybrid selection ; Protein-S14 ; Translation, in vitro ; Two-dimensional gel electrophoresis

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Medicine

Electronic Resource

1600-0501

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Abstract: Titanium abutments in dental implants shine through all-ceramic crowns and therefore limit excellent esthetic results. Prototypes of tooth-colored fiber-reinforced abutments were investigated to avoid the shining-through effect. In vitro, the fracture strength was determined after thermal cycling and mechanical loading of all-ceramic single crowns and four-unit bridges made of a fiber-reinforced composite. The suprastructures were adhesively fixed onto fiber-reinforced implant abutments and compared with those fixed on standard titanium abutments. The median of the fracture strength of the titanium-supported all-ceramic crowns was significantly higher than the median of crowns fixed onto the prototypes. But this value was still more than twice as high as the maximum loading force under oral conditions. No statistical difference was found between four-unit bridges made by fiber-reinforced composite inserted onto titanium abutments and those inserted onto fiber-reinforced abutments. Fiber-reinforced abutment prototypes for dental implants avoided the shining-through effect associated with metal abutments. Their load-bearing capacity after in vitro stress simulation was higher than the maximum oral loading force. With some improvements, the fiber-reinforced implant abutments are therefore a promising alternative to titanium abutments.

Electronic Resource

1436-3771

Key words Technical failure rate ; Conical crowns ; Telescopic crowns ; Removable partial denture ; Clinical study

Springer Online Journal Archives 1860-2000

Medicine

Abstract  Removable partial dentures (RPD) can be retained using conical crowns or parallel-sided telescopic double crowns. The purpose of this study was to evaluate and compare the technical failure rate of the two retainer systems. One hundred seventeen dentures made by dentists of the medical school were included. Seventy-four RPD were retained with parallel-sided crowns (n=251) and 43 with conical crowns (n=160). Following the medical report follow-ups from January 1992 to December 1998, technical RPD failures were noted and analyzed. Technical problems occurred during the observation time in 48.8% of the conical retained dentures and 34.2% of the parallel-sided retained dentures. In both cases, loss of cementation was most frequently noted, while loss of the facings occurred only with conical crowns. Other technical failures did not depend on the type of retainer system used. These were most frequently problems with the denture base, e.g., fracture of artificial teeth or the metal framework. We conclude that there were different technical failures of both double crown retainer systems. These problems were not insignificant in number but treatable.

Electronic Resource

1436-3771

Key words Adhesive-fixed partial denture ; Resin-bonded adhesive-fixed partial dentures ; Long-term results ; Clincial study

Springer Online Journal Archives 1860-2000

Medicine

Abstract Within the framework of an on-going prospective clinical study begun in 1985, 120 adhesive-fixed partial dentures (AFPD) continued to be examined. The manufacture and the fitting of the AFPDs were carried out following a standard procedure. The preparation technique and the metal framework conditioning (silica-coating, sandblasting and electrochemical etching) has varied throughout the duration of the study. Using Kaplan-Meier analysis, the survival rate was determined and an analysis of risk with regard to location factors (anterior, posterior; maxilla, mandible), conditioning and preparation techniques (retentive/non-retentive) was determined using the Cox regression model. The location of the AFPD had no influence on the survival rate. The survival time was determined mainly by the preparation technique. Strict preparation of seating grooves and pin holes made a 95% survival rate possible after 10 years (Kaplan-Meier estimation). Without retention, the risk of failure increased by a factor of 3.7.

Electronic Resource

1436-3771

Key words Adhesive-fixed partial denture ; Resin-bonded adhesive-fixed partial denture in vivo/in vitro study ; Artificial environment ; Retentive preparation technique ; Non-retentive preparation technique

Springer Online Journal Archives 1860-2000

Medicine

Abstract  The objective was to investigate associations between the results of an in vitro and an in vivo study using an artificial mouth and a study of adhesive fixed partial dentures (AFPD) begun in 1985 [1]. Twenty extracted human molars and 20 human upper incisors were inserted into PMMA resin, 6 mm apart to represent a gap. Two preparation methods (identical to those in in vivo conditions) were used: a retentive preparation technique (posterior) and a non-retentive preparation technique (anterior). The frameworks of the bridges consisted of CoCr-alloy with a ceramic veneered pontic to replace the missing tooth. The bonding surfaces of the posterior AFPDs were conditioned with a tribochemical system, while the anterior AFPDs were sandblasted. All AFPDs were inserted using a dual curing composite cement. During thermal-cycling and mechanical loading (TCML: 6000×5°C/55°C, 1.2×106×50 N, 1.66 Hz) in an artificial environment, the frequency and type of failures were observed. The above mentioned loading parameters were hypothesized to represent a period of 5 years under oral conditions. The results were compared to those of similar bridge-types in the in vivo study. The Kaplan-Meier estimations showed similar graphs for in vivo and in vitro with both types of AFPDs. In vivo and in vitro, the retentively prepared AFPDs were markedly more successful. With regard to the failure types, the simulation-parameters seemed to represent a loading stress that was comparable to in vivo conditions.

Electronic Resource

1432-0924

Springer Online Journal Archives 1860-2000

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Abstract Flow simulation is a computational tool for exploring science and technology involving flow applications. It can provide cost-effective alternatives or complements to laboratory experiments, field tests and prototyping. Flow simulation relies heavily on high performance computing (HPC). We view HPC as having two major components. One is advanced algorithms capable of accurately simulating complex, real-world problems. The other is advanced computer hardware and networking with sufficient power, memory and bandwidth to execute those simulations. While HPC enables flow simulation, flow simulation motivates development of novel HPC techniques. This paper focuses on demonstrating that flow simulation has come a long way and is being applied to many complex, real-world problems in different fields of engineering and applied sciences, particularly in aerospace engineering and applied fluid mechanics. Flow simulation has come a long way because HPC has come a long way. This paper also provides a brief review of some of the recently-developed HPC methods and tools that has played a major role in bringing flow simulation where it is today. A number of 3D flow simulations are presented in this paper as examples of the level of computational capability reached with recent HPC methods and hardware. These examples are, flow around a fighter aircraft, flow around two trains passing in a tunnel, large ram-air parachutes, flow over hydraulic structures, contaminant dispersion in a model subway station, airflow past an automobile, multiple spheres falling in a liquid-filled tube, and dynamics of a paratrooper jumping from a cargo aircraft.

Electronic Resource