Effect of different irrigation activation methods on non-infected dentinal tubule penetration of medicaments: A CLSM study.

Background: The whole root canal disinfection is crucial in terms of long-term endodontic success. In this context, applying medicaments following effective irrigation activation procedures becomes an important point. Aims: The purpose of this study was to evaluate and compare the efficacy of various irrigation activation techniques on non-infected dentinal tubule penetration of calcium hydroxide (CH), double (DAP), and triple (TAP) antibiotic pastes. Materials and Methods: A total of 180 extracted human permanent mandibular premolar single-rooted teeth were selected and randomly divided into a control group and four main groups according to the irrigation activation procedures (n = 36) as KTP laser irradiation, conventional needle, NaviTip FX, sonic (SI) and ultrasonic activation (UI) procedures. Each group was randomly subdivided into three subgroups according to the medicament type (n = 12); CH, DAP, and TAP. After the activation procedures, the root canals were filled with CH, TAP, and DAP mixed with 0.1% fluorescent rhodamine B isothiocyanate. Specimens were sectioned at 2, 5, and 8 mm from the apex, and all the sections were examined under a confocal laser scanning microscope to calculate the dentinal tubule penetration. Data were analyzed using a three-way analysis of variance and Tukey's post hoc tests (P = 0.05). Results: TAP provided a statistically significant greater penetration than the other groups (P < 0.05). UI provided a statistically significant higher dentinal tubules penetration area than other activation procedures (P < 0.05). Conclusion: Medicament penetration depends on the type of medicament, activation procedures, and root canal level. The TAP may be preferred following the ultrasonic activation in terms of long term root canal treatment success.

Evaluating efficacy of different post materials and lengths on bonding strength between root canal dentin and post restorations: An experimental study.

BACKGROUND: During post restoration, different root structures require several types of posts to increase duration of their clinical use. Several materials have been investigated to enhance their quality and optimize their length according to the available root canal. AIMS: The aim of this study was to determine the effect of zirconia, fiber, and ceromer posts with 3- and 6-mm post sizes on the bonding strength of them to root canal dentinal wall with the means of pull-out bond strength test. METHODS: Forty-eight single-rooted mandibular human premolar teeth were collected and prepared for this in vitro study. With resin cement, 3- and 6-mm study posts including zirconia, fiber, and ceromer were luted to prepare teeth. For the retention testing, the pull-out force was applied to each specimen parallel to longitudinal axis of both the post and tooth. RESULTS: Both type of materials and size of posts changed the value of bonding strength. In all the post types, 6-mm ones performed better. Overall, the best bonding strength was obtained with fiber posts and the better bonding strength was obtained with zirconia; however, ceromer provided the least bonding strength. CONCLUSION: Current experiments supported that 6-mm post size can increase the bonding between root canal dentin and studied posts. When considering post materials, fiber provided the best bonding strength in current laboratory setup. Second, zirconia had meaningfully acceptable bonding strength; however, the bonding strength of ceromer posts was not favorable. Further studies optimizing post fabrication techniques of root materials may increase the bonding strength of posts to human dentin to an acceptable clinical degree.

Pharmacokinetics and pharmacodynamics of a single dose of sustained-release azithromycin formulation in pigeons.

To date, only a few studies on the azithromycin (AZM) pharmacokinetics in ornamental birds have been published. In the current study AZM concentrations in domestic pigeon (Columba livia domestica) plasma samples were analyzed using a validated ultra-high performance liquid chromatography tandem mass spectrometry method. The aim of the current study was to carry out an analysis of the pharmacokinetics and pharmacodynamics after administration of a single oral dose of a sustained-release AZM formulation and to conduct a simulation of treatment based on selected minimal inhibitory values. The study was performed with 12 healthy adult pigeons, both sexes. The pigeons tolerated AZM very well and no adverse effects were observed in any animal during the study. Based on the observed characteristics of the pharmacokinetics/ /pharmacodynamics profiles of AZM in pigeons, it should be noted that 35 mg/kg per os as a single starting dose and 25 mg/kg every 24 h are recommended for treatment of both suscep- tible and less susceptible pathogens.

Three-dimensional printing of metals for biomedical applications.

Three-dimensional (3D) printing technology has received great attention in the past decades in both academia and industry because of its advantages such as customized fabrication, low manufacturing cost, unprecedented capability for complex geometry, and short fabrication period. 3D printing of metals with controllable structures represents a state-of-the-art technology that enables the development of metallic implants for biomedical applications. This review discusses currently existing 3D printing techniques and their applications in developing metallic medical implants and devices. Perspective about the current challenges and future directions for development of this technology is also presented.

Apically extruded debris during root canal preparation using Vortex Blue, K3XF, ProTaper Next and Reciproc instruments.

AIM: To assess the amount of debris extruded apically during root canal preparation using various nickel-titanium instrumentation systems. METHODOLOGY: Sixty extracted single-rooted mandibular premolar human teeth were randomly assigned to four groups (n = 15 teeth for each group). The canals were then instrumented with the following instrument systems: Vortex Blue (VB; Dentsply Tulsa Dental, Tulsa, OK, USA), K3XF (SybronEndo, Orange, CA, USA), Reciproc (VDW, Munich, Germany) and ProTaper Next (PTN; Dentsply Maillefer, Ballaigues, Switzerland). Apically extruded debris during instrumentation was collected into pre-weighed Eppendorf tubes. The Eppendorf tubes were then stored in an incubator at 70 °C for 5 days. The weight of the dry extruded debris was established by subtracting the pre-instrumentation and post-instrumentation weight of the Eppendorf tubes for each group. The data were analysed using one-way analysis of variance (anova) and Tukey's post hoc tests. RESULTS: Vortex Blue and PTN files were associated with significantly less apically extruded debris than the K3XF and Reciproc files (P < 0.05), but there was no significant difference between the VB and PTN files or between the K3XF and Reciproc files (P > 0.05). CONCLUSIONS: All instruments were associated with apical extrusion of debris. VB and PTN files were associated with less debris extrusion compared to the other systems.

Tempo and mode of recurrent polyploidization in the Carassius auratus species complex (Cypriniformes, Cyprinidae).

Polyploidization is an evolutionarily rare but important mechanism in both plants and animals because it increases genetic diversity. Goldfish of the Carassius auratus species complex can be tetraploids, hexaploids and octaploids. Polyploidization events have occurred repeatedly in goldfish, yet the extent of this phenomenon and its phyletic history are poorly understood. We explore the origin, tempo and frequency of polyploidization in Chinese and Japanese goldfish using both mitochondrial (mtDNA) and nuclear DNA sequences from up to 1202 individuals including the outgroup taxon, Cyprinus carpio. Analyses of de novo nuclear gene data resolve two clusters of alleles and the pattern supports the prior hypothesis of an ancient allotetraploidization for Carassius. Alleles shared by tetraploid and hexaploid individuals indicate recent autoploidizations within the C. auratus complex. Sympatric tetraploids and hexaploids share mtDNA haplotypes and these frequently occur independently within six well-supported lineages and sublineages on a small spatial scale. Gene flow estimates (Fst values) indicate that hexaploids differ only slightly from sympatric tetraploids, if at all. In contrast, allopatric populations of tetraploids and hexaploids differ from one another to a far greater extent. Gene flow between sampled localities appears to be limited. Coalescence-based time estimations for hexaploids reveal that the oldest lineage within any sampled locality is around one million years old, which is very young. Sympatric, recurrent autoploidization occurs in all sampled populations of the C. auratus complex. Goldfish experience polyploidization events more frequently than any other vertebrate.

Ion implantation of graphene-toward IC compatible technologies.

Doping of graphene via low energy ion implantation could open possibilities for fabrication of nanometer-scale patterned graphene-based devices as well as for graphene functionalization compatible with large-scale integrated semiconductor technology. Using advanced electron microscopy/spectroscopy methods, we show for the first time directly that graphene can be doped with B and N via ion implantation and that the retention is in good agreement with predictions from calculation-based literature values. Atomic resolution high-angle dark field imaging (HAADF) combined with single-atom electron energy loss (EEL) spectroscopy reveals that for sufficiently low implantation energies ions are predominantly substitutionally incorporated into the graphene lattice with a very small fraction residing in defect-related sites.

Diurnal and seasonal changes in endogenous melatonin levels in the blood plasma in dogs.

This paper describes research on the levels of endogenous melatonin (MLT) in the blood serum in dogs in different seasons (March, June, September, December) and at different times of day (11:00, 12:00, 23:00, 24:00 and 1:00), using immunoassay method. Blood samples were collected in the diurnal cycle, in consecutive seasons. The conducted studies show that MLT levels undergo clear changes in both the diurnal cycle, as well as in seasonal one in this species.

Imaging of Bernal stacked and misoriented graphene and boron nitride: experiment and simulation.

Experimental atomic resolution bright and high angle dark field transmission electron microscopy images of mono- and few-layer graphene and boron nitride, as well as of turbostratic arrangements in both materials, are compared to their simulated counterparts. Changes in the images according to defocus, layer number and accelerating voltage are discussed. It emerges that simulations with realistic microscope parameters accurately depict experimental graphene and boron nitride images and present a reliable tool for their interpretation.

Exploring factors shaping population genetic structure of the freshwater fish Sinocyclocheilus grahami (Teleostei, Cyprinidae).

Phylogeographical analyses on Sinocyclocheilus grahami samples from seven localities within the Lake Dianchi Basin in China were conducted to explore the main factors shaping population structure within this species. Phylogenetic and network analyses revealed two major clades in 24 mtDNA haplotypes. One clade included three haplotypes exclusively from samples of the lower basin and another clade encompassed other haplotypes from samples of the upper basin. The estimated divergence time between the two clades predated the river capture event connecting the lower and upper lake basin and thus supported geographical isolation as the main factor shaping genetic divergence between these two clades. Furthermore, analysis of molecular variance and pair-wise Phi(ST) distances revealed significant genetic differentiation within the upper basin. Mantel tests clearly supported patterns of differentiation arose purely as a result of isolation by distance. These results further highlight the importance of geographical isolation in shaping differentiation within this species.

Pharmacokinetics of tylosin in broiler chickens.

Biological availability and pharmacokinetic properties of tylosin were determined in broiler chickens after oral (p.o.) and intravenous (i.v.) administration at a dose of 10 mg/kg. The calculated bioavailability--F%, by comparing AUC values--p.o. and AUC--i.v., ranged from 30%-34%. After intravenous injection tylosin was rapidly distributed in the organism, showing elimination half-life (t1/2 beta) values of 0.52 h and distribution volume (Vd) of 0.69 L/kg, at a clearance rate (Cl) of 5.30 +/- 0.59 ml/min/kg. After oral administration, tylosin has a similar distribution volume (Vd = 0.85 L/kg), while the elimination half-life t1/2 beta of 2.07 h was four times bigger than after i.v. administration at Cl = 4.40 +/- 0.27 ml/min/kg. The obtained value tmax = 1.5 h for tylosin after oral administration indicates that using this antibiotic with drinking water in broiler chickens is the method of choice. However, a relatively low value Cmax = 1.2 micrograms/ml after oral administration of tylosin shows that dosing of this antibiotic in broiler chickens should be higher than in other food producing animals.

Bacterial resistance to quinolone antibiotics in Poland.

The resistance of 167 pathogenic bacteria of animal origin to quinolones was determined by the disc diffusion method, and by the minimum inhibitory concentration (MIC) test. The highest resistance of Escherichia coli was found to be against nalidixic acid (NA), 49.1% and flumequine (FLU), 38.2%. The sensitivity of the strains were: ciprofloxacin (CIP; 81.8%); enrofloxacin (ENR; 81.8%); norfloxacin (NOR; 80.0%); and pefloxacin (PE; 76.4%). Salmonella spp. showed 100% sensitivity to CIP, ENR, NOR and PE. A high resistance percentage in the cases of: FLU (86.7%); PE (50.0%); and CIP (26.65%) distinguished the Streptococcus spp. The highest percentage sensitivity of Staphylococci was found with three fluoroquinolones: CIP, ENR and NOR, 94.3% each (66 strains). The studies did not indicate that a total cross-resistance might occur between the examined quinolones.