Reinterventions after dynamic intraligamentary stabilization in primary anterior cruciate ligament repair

Background

The goal of this study was to perform an in-depth analysis of the frequency and cause of secondary interventions subsequent to primary anterior cruciate ligament (ACL) repair with dynamic intraligamentary stabilization (DIS).

Iodine Images in Dual-energy CT: Detection of Hepatic Steatosis by Quantitative Iodine Concentration Values

Hepatic steatosis is a common condition and an early manifestation of a systemic metabolic syndrome. As of today, there is no broadly accepted method for the diagnosis of hepatic steatosis in contrast-enhanced CT images. This retrospective study evaluates the potential of quantitative iodine values in portal venous phase iodine images in dual-energy CT (DECT) by measuring iodine concentrations in regions of interest (ROI) and analyzing the absolute iodine concentration of the liver parenchyma as well as three different blood-normalized iodine concentrations in a study cohort of 251 patients. An independent two sample t-test (p < 0.05) was used to compare the iodine concentrations of healthy and fatty liver. Diagnostic performance was assessed by ROC (receiver operating characteristic) curve analysis. The results showed significant differences between the average iodine concentration of healthy and fatty liver parenchyma for the absolute and for the blood-normalized iodine concentrations. The study concludes that the iodine uptake of the liver parenchyma is impaired by hepatic steatosis, and that the measurement of iodine concentration can provide a suitable method for the detection of hepatic steatosis in quantitative iodine images. Suitable thresholds of quantitative iodine concentration values for the diagnosis of hepatic steatosis are provided.     

Systematik der Frühkindlichen Lungenentzündungen nach Allgemeinpathologischen Gesichtspunkten auf Grund von Klinischen und Röntgenbefunden

Ohne Zusammenfassung     

A new method to quantify wear using implant supported restorations.

OBJECTIVES: To design a novel technique to assess the wear of prosthodontic veneering materials. Further to determine whether accurate transfer between the oral cavity and the measuring device is achievable and assess the reproducibility of the coordinates generated by the measuring system. METHODS: The system is based on the repositioning capacity of an octagonal connector of the ITI implant system. The same type of connector was screwed onto the clinical implants that supported the experimental restorations and secured to the x-y table of the measuring device. The measuring setup also comprised a z-axis LVDT displacement gauge that allowed the entire surface of the restorations to be profiled and digitized. The system was under the control of a PC equipped with custom-made software that set the position of the stepping motors, lifted and lowered the z-axis probe, and registered and wrote the x-, y- and z-axis coordinates. Final numerical adjustments and analyses were performed using a commercial array-oriented software package. Validation procedures were performed using a specially designed calibration surface. RESULTS: On repeated profile tracings, the measurement error was less than 2 microns. When the calibration surface was removed between measurements as during clinical trials, the measurement error increased to ca. 5 microns. SIGNIFICANCE: The measurement error of the testing procedure including transfer to and from the mouth is +/- 5 microns.     

Rotational fatigue-resistance of seven post types anchored on natural teeth.

PURPOSE: To develop a laboratory model aimed at duplicating the failure process of post and core restorations. The load pattern applied was to be repetitive (fatigue) and multivectorial. To determine and compare the resistance under fatigue loading of seven endodontic post/natural root combinations: stainless steel-, titanium-, ceramic-, composite-fiber/epoxy-, two glass-fiber/epoxy- and glass-fiber/acrylic posts. MATERIALS AND METHODS: The repetitive, alternating and multivectorial intraoral force pattern was reproduced by subjecting the specimens to the rotating cantilever beam test. To this end, the samples were designed as rotation-symmetric structures comprising a root, a post, periodontal ligament- and bone analogs and a restoration analog. The following posts were tested: Unimetric-Ti, Unimetric-SS, Biopost, Composipost, Easypost, DT Lightpost, Everstickpost. The samples were spun around their long axes while being clamped into a revolving collet on one end and loaded normal to their long axis on the other end. The aim was to determine the load level at which 50% of the specimens survived- and 50% fractured before 10E6 cycles. The 50% means were determined using the staircase procedure. RESULTS: In increasing order of magnitude, the resistances to fatigue loading were as follows: Biopost, Unimetric-Ti, Unimetric-SS, Composipost, Easypost, Everstickpost, DT Lightpost. SIGNIFICANCE: The fatigue resistance of the two fibrous posts with the highest fatigue resistance was twice that of any of the ceramic or metal posts.     

Slow feature analysis yields a rich repertoire of complex cell properties

In this study we investigate temporal slowness as a learning principle for receptive fields using slow feature analysis, a new algorithm to determine functions that extract slowly varying signals from the input data. We find a good qualitative and quantitative match between the set of learned functions trained on image sequences and the population of complex cells in the primary visual cortex (V1). The functions show many properties found also experimentally in complex cells, such as direction selectivity, non-orthogonal inhibition, end-inhibition, and side-inhibition. Our results demonstrate that a single unsupervised learning principle can account for such a rich repertoire of receptive field properties.     

Medium-Term Function of a 3D Printed TCP/HA Structure as a New Osteoconductive Scaffold for Vertical Bone Augmentation: A Simulation by BMP-2 Activation

Introduction: A 3D-printed construct made of orthogonally layered strands of tricalcium phosphate (TCP) and hydroxyapatite has recently become available. The material provides excellent osteoconductivity. We simulated a medium-term experiment in a sheep calvarial model by priming the blocks with BMP-2. Vertical bone growth/maturation and material resorption were evaluated. Materials and methods: Titanium hemispherical caps were filled with either bare- or BMP-2 primed constructs and placed onto the calvaria of adult sheep (n = 8). Histomorphometry was performed after 8 and 16 weeks. Results: After 8 weeks, relative to bare constructs, BMP-2 stimulation led to a two-fold increase in bone volume (Bare: 22% ± 2.1%; BMP-2 primed: 50% ± 3%) and a 3-fold decrease in substitute volume (Bare: 47% ± 5%; BMP-2 primed: 18% ± 2%). These rates were still observed at 16 weeks. The new bone grew and matured to a haversian-like structure while the substitute material resorbed via cell- and chemical-mediation. Conclusion: By priming the 3D construct with BMP-2, bone metabolism was physiologically accelerated, that is, enhancing vertical bone growth and maturation as well as material bioresorption. The scaffolding function of the block was maintained, leaving time for the bone to grow and mature to a haversian-like structure. In parallel, the material resorbed via cell-mediated and chemical processes. These promising results must be confirmed in clinical tests.