Failure Load of Monolithic Lithium Disilicate Implant-Supported Single Crowns Bonded to Ti-base Abutments versus to Customized Ceramic Abutments after Fatigue.

PURPOSE: This laboratory study analyzed the influence of retention mode (screw- vs cement retained) and fatigue application on the failure load of monolithic lithium-disilicate (LDS) implant-supported single crowns (ISSC). MATERIAL AND METHODS: A total of 72 samples of monolithic LDS (*Ivoclar Vivadent) ISSC were divided into three groups (n = 24) according to their type of retention mode: Group Ti-CAD: Titanium base (SICvantage CAD/CAM Abutment red (SIC invent AG), screw-retained milled monolithic LDS (IPS e.max CAD*); Group Ti-P: Titanium base (SICvantage CAD/CAM Abutment red), screw-retained pressed monolithic LDS (IPS e.max Press*) and Group Ti-Cust: Titanium base with cemented press LDS (IPS e.max Press*) crown on a LDS (IPS e.max Press*) custom abutment. A mandibular first molar implant-supported single crown model was investigated (Titanium implant: SICvantage-max, SIC invent AG, diameter: 4.2 mm, length: 11.5 mm). Half of each group (n = 12) w​ere exposed to fatigue with cyclic mechanical loading (F = 198 N, 1.2 million cycles) and simultaneous thermocycling (5-55°C). Single load to failure testing was performed, before (Subgroups Ti-CAD, Ti-P, and Ti-Cust) and after (Subgroups Ti-CAD-F, Ti-P-F, and Ti-Cust-F) fatigue. Weibull distribution was used to determine the characteristic strength and Weibull modulus differences between groups. Probability of survival at 900N load was calculated. RESULTS: No samples failed during fatigue. Characteristic strength values were as follow: Ti-CAD: 3259.5N, Ti-CAD-F: 2926N, Ti-P: 2763N, Ti-P-F: 2841N, Ti-Cust: 2789N, Ti-Cust-F: 2194N. Whereas no difference was observed between pressed or milled monolithic crowns cemented to Ti-base, regardless of loading condition, fatigue decreased the characteristic strength of crowns cemented to custom abutments. Probability of survival at 900 N was not significantly different between groups. CONCLUSIONS: Screw-retained pressed or milled monolithic LDS ISSC, cemented directly to Ti-base abutments or LDS crowns cemented to custom ceramic abutments resist physiological chewing forces after simulated 5-year aging in the artificial mouth and presented equally high probability of survival. However, a significant decrease in load to failure was observed in LDS crowns cemented to custom ceramic abutments after fatigue. Prospective clinical trials are needed to confirm the results of this laboratory investigation.

Ratiometric detection of oligonucleotide stoichiometry on multifunctional gold nanoparticles by whispering gallery mode biosensing.

A label-free method is developed to ratiometrically determine the stoichiometry of oligonucleotides attached to the surface of gold nanoparticle (GNP) by whispering gallery mode biosensing. Utilizing this scheme, it is furthermore shown that the stoichiometric ratio of GNP attached oligonucleotide species can be controlled by varying the concentration ratio of thiolated oligonucleotides that are used to modify the GNP.

Comparison of different reconstruction algorithms for three-dimensional ultrasound imaging in a neurosurgical setting.

BACKGROUND: Freehand three-dimensional ultrasound imaging (3D-US) is increasingly used in image-guided surgery. During image acquisition, a set of B-scans is acquired that is distributed in a non-parallel manner over the area of interest. Reconstructing these images into a regular array allows 3D visualization. However, the reconstruction process may introduce artefacts and may therefore reduce image quality. The aim of the study is to compare different algorithms with respect to image quality and diagnostic value for image guidance in neurosurgery. METHODS: 3D-US data sets were acquired during surgery of various intracerebral lesions using an integrated ultrasound-navigation device. They were stored for post-hoc evaluation. Five different reconstruction algorithms, a standard multiplanar reconstruction with interpolation (MPR), a pixel nearest neighbour method (PNN), a voxel nearest neighbour method (VNN) and two voxel based distance-weighted algorithms (VNN2 and DW) were tested with respect to image quality and artefact formation. The capability of the algorithm to fill gaps within the sample volume was investigated and a clinical evaluation with respect to the diagnostic value of the reconstructed images was performed. RESULTS: MPR was significantly worse than the other algorithms in filling gaps. In an image subtraction test, VNN2 and DW reliably reconstructed images even if large amounts of data were missing. However, the quality of the reconstruction improved, if data acquisition was performed in a structured manner. When evaluating the diagnostic value of reconstructed axial, sagittal and coronal views, VNN2 and DW were judged to be significantly better than MPR and VNN. CONCLUSION: VNN2 and DW could be identified as robust algorithms that generate reconstructed US images with a high diagnostic value. These algorithms improve the utility and reliability of 3D-US imaging during intraoperative navigation.

Whispering Gallery Mode Carousel--a photonic mechanism for enhanced nanoparticle detection in biosensing.

Individual nanoparticles in aqueous solution are observed to be attracted to and orbit within the evanescent sensing ring of a Whispering Gallery Mode micro-sensor with only microwatts of driving power. This Carousel trap, caused by attractive optical gradient forces, interfacial interactions, and the circulating momentum flux, considerably enhances the rate of transport to the sensing region, thereby overcoming limitations posed by diffusion on such small area detectors. Resonance frequency fluctuations, caused by the radial Brownian motion of the nanoparticle, reveal the radial trapping potential and the nanoparticle size. Since the attractive forces draw particles to the highest evanescent intensity at the surface, binding steps are found to be uniform.

Single virus detection from the reactive shift of a whispering-gallery mode.

We report the label-free, real-time optical detection of Influenza A virus particles. Binding of single virions is observed from discrete changes in the resonance frequency/wavelength of a whispering-gallery mode excited in a microspherical cavity. We find that the magnitude of the discrete wavelength-shift signal can be sufficiently enhanced by reducing the microsphere size. A reactive sensing mechanism with inverse dependence on mode volume is confirmed in experiments with virus-sized polystyrene nanoparticles. By comparing the electromagnetic theory for this reactive effect with experiments, the size and mass ( approximately 5.2 x 10(-16) g) of a bound virion are determined directly from the optimal resonance shift.

Experimental observation of strong photon localization in disordered photonic crystal waveguides.

We demonstrate experimentally that structural perturbations imposed on highly dispersive photonic crystal-based waveguides give rise to spectral features that bear signatures of Anderson localization. Sharp resonances with effective Q's of over 30 000 are found in scattering spectra of disordered waveguides. The resonances are observed in a approximately 20-nm bandwidth centered at the cutoff of slowly guided Bloch modes. The origin of the spectral features can be explained by the interference of coherently scattered electromagnetic waves which results in the formation of a narrow impurity (or localization) band populated with spectrally distinct quasistates. Standard photon localization criteria are fulfilled in the localization band.

Shift of whispering-gallery modes in microspheres by protein adsorption.

Biosensors based on the shift of whispering-gallery modes in microspheres accompanying protein adsorption are described by use of a perturbation theory. For random spatial adsorption, theory predicts that the shift should be inversely proportional to microsphere radius R and proportional to protein surface density and excess polarizability. Measurements are found to be consistent with the theory, and the correspondence enables the average surface area occupied by a single protein to be estimated. These results are consistent with crystallographic data for bovine serum albumin. The theoretical shift for adsorption of a single protein is found to be extremely sensitive to the target region, with adsorption in the most sensitive region varying as 1/R(5/2). Specific parameters for single protein or virus particle detection are predicted.

Human TATA-binding protein-related factor-2 (hTRF2) stably associates with hTFIIA in HeLa cells.

The TATA-binding protein (TBP)-related factor TRF1, has been described in Drosophila and a related protein, TRF2, has been found in a variety of higher eukaryotes. We report that human (h)TRF2 is encoded by two mRNAs with common protein coding but distinct 5' nontranslated regions. One mRNA is expressed ubiquitously (hTRF2-mRNA1), whereas the other (hTRF2-mRNA2) shows a restricted expression pattern and is extremely abundant in testis. In addition, we show that hTRF2 forms a stable stoichiometric complex with hTFIIA, but not with TAFs, in HeLa cells stably transfected with flag-tagged hTRF2. Neither recombinant human (rh)TRF2 nor the native flag.hTRF2-TFIIA complex is able to replace TBP or TFIID in basal or activated transcription from various RNA polymerase II promoters. Instead, rhTRF2, but not the flag.hTRF2-TFIIA complex, moderately inhibits basal or activated transcription in the presence of rhTBP or flag.TFIID. This effect is either completely (TBP-mediated transcription) or partially (TFIID-mediated transcription) counteracted by addition of free TFIIA. Neither rhTRF2 nor flag. hTRF2-TFIIA has any effect on the repression of TFIID-mediated transcription by negative cofactor-2 (NC2) and neither substitutes for TBP in RNA polymerase III-mediated transcription.

[Polymorphous ventricular tachycardia occurring three months following radiofrequency ablation of the bundle of His]. / Tachycardies ventriculaires polymorphes survenant trois mois après une ablation par radiofréquence du faisceau de HIS.

The authors report the case of a 73-year-old patient presenting with polymorphous ventricular tachycardias one to 3 months after radiofrequency His bundle resection, as soon as the pacing frequency was reduced to 70 bpm. The clinical history revealed the existence of a possible clinical predisposition, as this patient had experienced an episode of torsade de pointe induced by hydroquinidine, one year previously. This case illustrates the importance of selecting a sufficiently high minimal stimulation frequency after His bundle resection.

Photochemical mechanisms producing large fluorescence stokes shifts.

Various adiabatic photochemical mechanisms are compared which lead to a product in the excited state and therefore often to strongly red-shifted fluorescence. The applicational aspects of this strong red shift are outlined with respect to scinitillators, solar collectors, and biological fluorescence probese. As an example, the unusual fluorecence properties of a pyrazalocoumarin derivative are described.

[A case of cholestatic hepatitis caused by amiodarone]. / A propos d'un cas d'hépatite cholestatique à l'amiodarone.

The authors report the case of a 70 year old male patient, who was treated with amiodarone for 9 months (200 mg/d-5 days/7) for alcohol-induced hypokinetic cardiomyopathy, complicated by ventricular dysrhythmia and hospitalized for jaundice, pruritus, and deterioration of his general condition. Alkaline phosphatases were elevated significantly (7 times the upper limit for normal) with a moderate rise in serum transaminases twice the upper limit for normal). Ultrasound of the liver and biliary tract was normal. There were no serum markers for hepatitis B virus. No anti-tissue antibodies were found. A liver biopsy revealed portal and septal fibrosis, and polymorphous inflammatory infiltration with a majority of polymorphonuclear neutrophils and Mallory bodies. Intracellular and intralysosomal phospholipid inclusions were observed with electron microscopy. Clinical and laboratory test value outcome was favorable two weeks after cessation of administration of amiodarone.

[Paroxysmal mitral insufficiency caused by ischemic dysfunction of the papillary muscles. Apropos of 39 cases]. / Insuffisance mitrale paroxystique par dysfonctionnement ischémique de piliers. A propos de 39 observations.

Episodic mitral regurgitation due to ischaemia of one or both papillary muscles was studied in a review of 39 cases with complementary investigations and compared with previously reported data. The condition occurred after myocardial infarction in 69 p. 100 of cases (usually after inferior infarction: 54 p. 100) associated with ischaemia of the controlateral territory; there was no history of myocardial infarction in 31 p. 100 of cases. The patients were usually elderly (73 years), often hypertensive (77 p. 100) and diabetic (62 p. 100). The clinical syndrome was that of severe anginal pain, mitral regurgitation and left ventricular failure which was critical in some cases. The ECG showed typical ST depression (4.1 +/- 1.6 mm) especially in the antero-lateral leads; left bundle branch block (28 p. 100) with left axis deviation (18 p. 100), sometimes associated with changes of chronic infarction (64 p. 100) was also recorded. Mitral regurgitation and left ventricular failure regressed almost completely in typical cases between attacks, whilst the ECG showed slight residual sub-endocardial ischaemia (ST depression of 1.5 +/- 0.4 mm) in 30 cases and/or subepicardial ischaemia observed in the anterolateral leads in 13 cases. Phonomechanographic recordings (n = 32) showed moderate mitral regurgitation (1-2/6), usually parasystolic (47 p. 100) or early and mid systolic (36 p. 100) in 87.5 p. 100 of cases between attacks, aggravated by handgrip exercise and improved by trinitrin administration. Echocardiography (n = 27) only showed mitral valve changes in 2 patients (increased density of the papillary muscle in 1 case and prolapse of the anterior leaflet in 1 case); however, segmental wall hypokinetic (51 p. 100) or dyskinetic (15 p. 100) motion, was common with increased left ventricular end diastolic dimensions (mean 56.3 +/- 8.0 mm) and decreased fractional shortening (mean 0.30 +/- 0.07) (67 p. 100). Left atrial dimensions were increased (mean 39.7 +/- 6.4 mm) in 52 p. 100 of patients. Thallium 201 myocardial scintigraphy (n = 32) showed hypofixation in 57 (36 p. 100) and a lacuna in 23 (14 p. 100) of the 160 segments analysed. Left ventricular angioscintigraphy (n = 27; 135 segments) showed hypokinesia in 72 segments (53 p. 100); 2.7 segments per patient), akinesia in 19 segments (15 p. 100; 0.7 segment per patient) and dyskinesia in 2 segments (1.5 p. 100); 0.1 segment per patient). The global ejection fraction was 46 +/- 13 p. 100. Coronary angiography (n = 8) showed significant diffuse atherosclerosis.(ABSTRACT TRUNCATED AT 400 WORDS)

Effects of antidepressants on the EEG of the rat.

The aim of the study was to detect whether antidepressants cause specific EEG effects in rats. The results presented are based on quantitative evaluation of a series of 6-min vigilance-controlled EEG recordings in rats under standardized conditions. Standard conditions comprised: a vigilance control, a rigid test procedure in which drugs and rats are divided according to a Greek-Latin square, and the same electrode placement. Computer analyses are based on an analysis of variance for which the averaged power spectral values are used as input. The use of a moving window technique in this type of EEG studies is introduced in comparison to the well-known use of fixed frequency bands. A number of antidepressants have been tested and several common characteristics are found.