Surface Modification of Titanium Dental Implants by Excimer Laser

The perfect osseointegration process of the dental implants depends among other factors on the surfact characteristics of the titanium. In this study enlarged mechanical roughness was produced by a laser-based technique, in order to decrease the healing period of the implant. There are different ways of forming laser induced surface structures. In the case of mask projection techniques the surface can be modified in larger areas and surface patterns. An ArF nanosecond excimer laser was used in the experiments because of the advantageous properties of the excimer beams. Effective polishing by homogeneous laser illumination in the 3-5 J/cm2 fluence range was performed as confirmed by SEM and AFM studies. Holes of about 20 mm diameter and 10 mm in depth, with high aspect ratio and protrusions around the edges were ablated into the titanium surface with subsequent pulses of ns ArF excimer laser. To avoid easily breakable protrusions we applied excimer pulse durations of 0.5 picoseconds. In this case we obtained melting- and ridge-free ablation of titanium. The laser treatment influenced the chemical composition of the surface in two respects. On the one hand it removed carbonaceous contamination as indicated by XPS and XRD measurements, demonstrating that cleaning of the surface does not alter the original crystalline structure. On the other hand, XPS measurements proved that pulsed laser oxidation in air increased the thickness of the surface oxide layer, promoting better osseointegration

The biocompatibility of titanium in a buffer solution: compared effects of a thin film of TiO2 deposited by MOCVD and of collagen deposited from a gel

This study aims at evaluating the biocompatibility of titanium surfaces modified according two different ways: (i) deposition of a bio-inert, thin film of rutile TiO2 by chemical vapour deposition (MOCVD), and (ii) biochemical treatment with collagen gel, in order to obtain a bio-interactive coating. Behind the comparison is the idea that either the bio-inert or the bio-active coating has specific advantages when applied to implant treatment, such as the low price of the collagen treatment for instance. The stability in buffer solution was evaluated by open circuit potential (OCP) for medium time and cyclic voltametry. The OCP stabilized after 5104 min for all the specimens except the collagen treated sample which presented a stable OCP from the first minutes. MOCVD treated samples stabilized to more electropositive values. Numeric results were statistically analysed to obtain the regression equations for long time predictable evolution. The corrosion parameters determined from cyclic curves revealed that the MOCVD treatment is an efficient way to improve corrosion resistance. Human dermal fibroblasts were selected for cell culture tests, taking into account that these cells are present in all bio-interfaces, being the main cellular type of connective tissue. The cells grew on either type of surface without phenotype modification. From the reduction of yellow, water-soluble 3-(4,5-dimethyldiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT cytotoxicity test), MOCVD treated samples offer better viability than mechanically polished Ti and collagen treated samples as well. Cell spreading, as evaluated from microscope images processed by the program Sigma Scan, showed also enhancement upon surface modification. Depending on the experimental conditions, MOCVD deposited TiO2 exhibits different nanostructures that may influence biological behaviour. The results demonstrate the capacity of integration in simulated physiologic liquids for an implant pretreated by either method

The rs13388259 Intergenic Polymorphism in the Genomic Context of the BCYRN1 Gene Is Associated with Parkinson’s Disease in the Hungarian Population

Parkinson's disease (PD) is a common neurodegenerative disorder characterized by bradykinesia, resting tremor, and muscle rigidity. To date, approximately 50 genes have been implicated in PD pathogenesis, including both Mendelian genes with rare mutations and low-penetrance genes with common polymorphisms. Previous studies of low-penetrance genes focused on protein-coding genes, and less attention was given to long noncoding RNAs (lncRNAs). In this study, we aimed to investigate the susceptibility roles of lncRNA gene polymorphisms in the development of PD. Therefore, polymorphisms (n = 15) of the PINK1-AS, UCHL1-AS, BCYRN1, SOX2-OT, ANRIL and HAR1A lncRNAs genes were genotyped in Hungarian PD patients (n = 160) and age- and sex-matched controls (n = 167). The rare allele of the rs13388259 intergenic polymorphism, located downstream of the BCYRN1 gene, was significantly more frequent among PD patients than control individuals (OR = 2.31; p = 0.0015). In silico prediction suggested that this polymorphism is located in a noncoding region close to the binding site of the transcription factor HNF4A, which is a central regulatory hub gene that has been shown to be upregulated in the peripheral blood of PD patients. The rs13388259 polymorphism may interfere with the binding affinity of transcription factor HNF4A, potentially resulting in abnormal expression of target genes, such as BCYRN1

Ausmaß und Formen genderbasierter Diskriminierung von Studentinnen und Ärztinnen an fünf Universitätskliniken in Deutschland - Ergebnisse einer Online-Umfrage

Objective: There is a gap in research on gender-based discrimination (GBD) in medical education and practice in Germany. This study therefore examines the extent and forms of GBD among female medical students and physicians in Germany. Causes, consequences and possible interventions of GBD are discussed.Methods: Female medical students (n =235) and female physicians (n =157) from five university hospitals in northern Germany were asked about their personal experiences with GBD in an online survey on self-efficacy expectations and individual perceptions of the "glass ceiling effect" using an open-ended question regarding their own experiences with GBD. The answers were analyzed by content analysis using inductive category formation and relative category frequencies. Results: From both interviewed groups, approximately 75% each reported having experienced GBD. Their experiences fell into five main categories: sexual harassment with subcategories of verbal and physical, discrimination based on existing/possible motherhood with subcategories of structural and verbal, direct preference for men, direct neglect of women, and derogatory treatment based on gender.Conclusion: The study contributes to filling the aforementioned research gap. At the hospitals studied, GBD is a common phenomenon among both female medical students and physicians, manifesting itself in multiple forms. Transferability of the results beyond the hospitals studied to all of Germany seems plausible. Much is known about the causes, consequences and effective countermeasures against GBD. Those responsible for training and employers in hospitals should fulfill their responsibility by implementing measures from the set of empirically evaluated interventions.Zielsetzung: Zur genderbasierten Diskriminierung (GBD) in der medizinischen Ausbildung und Tätigkeit besteht in Deutschland eine Forschungslücke. Die vorliegende Studie untersucht daher Ausmaß und Formen von GBD bei Medizinstudentinnen und Ärztinnen in Deutschland. Es werden Ursachen, Folgen und Interventionsmöglichkeiten von GBD diskutiert.Methodik: Medizinstudentinnen (n =235) und Ärztinnen (n =157) von fünf Universitätskrankenhäusern in Norddeutschland wurden im Rahmen einer Online-Umfrage zu Selbstwirksamkeitserwartung und Glasdeckeneffekt anhand einer offenen Frage nach ihren persönlichen Erfahrungen mit GBD befragt. Die Antworten wurden inhaltsanalytisch mittels induktiver Kategorienbildung und nach relativen Kategorienhäufigkeiten ausgewertet. Ergebnisse: Aus beiden befragten Gruppen gaben jeweils ca. 75% an, GBD erlebt zu haben. Ihre Erfahrungen lassen sich in fünf Hauptkategorien unterteilen: sexuelle Belästigung mit den Unterkategorien verbal und körperlich, Diskriminierung aufgrund bestehender/möglicher Mutterschaft mit den Unterkategorien strukturell und verbal, unmittelbare Bevorzugung von Männern, unmittelbare Vernachlässigung von Frauen und herabwürdigender Umgang aufgrund des Geschlechts.Schlussfolgerung: Die Studie leistet einen Beitrag, um die genannte Forschungslücke zu schließen. An den untersuchten Krankenhäusern ist GBD sowohl bei Medizinstudentinnen als auch bei Ärztinnen ein verbreitetes Phänomen, das sich in vielfältigen Formen manifestiert. Eine Übertragbarkeit der Ergebnisse über die untersuchten Krankenhäuser hinaus auf ganz Deutschland erscheint plausibel. Über die Ursachen, Folgen und wirkungsvolle Gegenmaßnahmen gegen GBD ist viel bekannt. Verantwortliche in Ausbildung und Arbeitgeber*innen in Krankenhäusern sollten ihrer Verantwortung gerecht werden, indem sie Maßnahmen aus der Menge der empirisch evaluierten Interventionen umsetzen

Reactive pulsed laser deposition of thin molybdenum- and tungsten-nitride films

In this work reactive pulsed laser deposition of molybdenum- and tungsten-nitride thin films is investigated. Metallic targets were ablated in low-pressure (1, 10 and 100 Pa) nitrogen atmosphere by KrF excimer laser pulses (fluence ~6.5 J/cm2). Films were deposited on silicon wafers heated to ~25, 250 and 500 8C. The characteristics of the films strongly depend on the N2 pressure. By increasing N2 pressure, the nitrogen content increases in the films, which leads to a monotonous increase of the electrical resistivity. Deposition rate decreases at 100 Pa as indicated by Rutherford backscattering spectrometry. At this pressure, hardness of the films significantly decreases also, as shown by microhardness measurements. X-ray diffractometry shows that films crystallinity is improved by increasing the substrate temperature. In addition, atomic force microscopy (AFM) and scanning electron microscopy (SEM) were applied for visualising the film surface