Measurement of the mass difference between top and anti-top quarks in pp collisions at View the MathML √s=7 TeV using the ATLAS detector

A measurement of the mass difference between top and anti-top quarks is presented. In a 4.7 fb−14.7 fb−1 data sample of proton–proton collisions at View the MathML sources=7 TeV recorded with the ATLAS detector at the LHC, events consistent with View the MathML sourcett¯ production and decay into a single charged lepton final state are reconstructed. For each event, the mass difference between the top and anti-top quark candidate is calculated. A two b -tag requirement is used in order to reduce the background contribution. A maximum likelihood fit to these per-event mass differences yields View the MathML sourceΔm≡mt−mt¯=0.67±0.61(stat)±0.41(syst) GeV, consistent with CPT invariance.

Differences between dual X-ray absorptiometry using pencil beam and fan beam modes and their determinants in vivo and in vitro

The aim of this study was to determine the influence of individual factors on differences in bone mineral density (BMD) using dual X-ray absorptiometry pencil beam (PB) and fan beam (FB) modes in vivo and in vitro. PB.BMD and FB.BMD of 63 normal Caucasian females ages 21-80 yr were measured at the lumbar spine and hip. Residuals of the FB/PB regression were used to assess the impact of height, weight, adiposity index (AI) (= weight/height(3/2)), back tissue thickness, and PB.BMD, respectively, on FB/PB difference. The Hologic Anthropomorphic Spine Phantom (ASP) was measured using the PB and FB modes at two different levels to assess the impact of scanning mode and focus distance. The European Spine Phantom (ESP) prototype, a geometrically well-defined phantom with known vertebral densities, was measured using PB and FB modes and analyzed manually to determine the impact of bone density on FB/PB difference and automatically to determine the impact of edge detection on FB/PB difference. Population BMD results were perfectly correlated, but significantly overestimated by 1.5% at the lumbar spine and underestimated by 0.7% at the neck, 1.8% at the trochanter, and 2.0% at the total hip, respectively, when using the FB compared with PB mode. At the lumbar spine, the FB/PB residual correlated negatively with height (r = 0.34, p < 0.01) and PB.BMD (r = 0.48, p <: 0. 0001) and positively with AI (r = 0.26, p < 0.05). At the hip, residual of trochanter correlated positively with weight (r = 0.36, p < 0.01) and AI (r = 0.36, p < 0.01). The FB mode significantly increased ASP BMD by 0.7% compared with PB. Using the FB mode, increasing focus distance significantly (p < 0.001) decreased area and bone mineral content, but not BMD. By contrast, increasing focus distance significantly decreased PB.BMD by 0.7%. With the ESP, the PB mode supplied accurate projected are of the bone (AREA) results but significant underestimation of specified BMD in the manual analysis. The FB mode significantly underestimated PB. AREA by 2.9% but fitted specified BMD quite well. FB/PB overestimation was larger for the low-density (+8.7%) than for the high-density vertebra (+4. 9%). The automated analysis resulted in more than 14% underestimation of PB. AREA (low-density vertebra) and an almost 13% overestimation of PB.BMD (high-density vertebra) using FB. In conclusion, FB and PB measurements are highly correlated at the lumbar spine and hip with small but significant BMD differences related to height, adiposity, and BMD. In clinical practice, it can be erroneous to switch from one method to another, especially in women with low bone density.

Comparison between the first and second generation bioresorbable vascular scaffolds: a six month virtual histology study

To compare the intravascular ultrasound virtual histology (IVUS-VH) appearance of the polymeric struts of the first (Revision 1.0) and the second (Revision 1.1) generation bioresorbable vascular scaffold (BVS).

What makes the difference between the natural course of a remaining type B dissection after type A repair and a primary type B aortic dissection?

To analyse the outcome and need for intervention [surgery or thoracic endovascular aortic repair (TEVAR)] in patients after surgery for remaining type B dissection after type A repair and primary type B aortic dissection.

A comparison between two-dimensional and three-dimensional cephalometry on frontal radiographs and on cone beam computed tomography scans of human skulls

The aim of this study was to evaluate whether measurements performed on conventional frontal radiographs are comparable to measurements performed on three-dimensional (3D) models of human skulls derived from cone beam computed tomography (CBCT) scans and if the latter can be used in longitudinal studies. Cone beam computed tomography scans and conventional frontal cephalometric radiographs were made of 40 dry human skulls. From the CBCT scan a 3D model was constructed. Standard cephalometric software was used to identify landmarks and to calculate ratios and angles. The same operator identified 10 landmarks on both types of cephalometric radiographs, and on all images, five times with a time interval of 1 wk. Intra-observer reliability was acceptable for all measurements. There was a statistically significant and clinically relevant difference between measurements performed on conventional frontal radiographs and on 3D CBCT-derived models of the same skull. There was a clinically relevant difference between angular measurements performed on conventional frontal cephalometric radiographs, compared with measurements performed on 3D models constructed from CBCT scans. We therefore recommend that 3D models should not be used for longitudinal research in cases where there are only two-dimensional (2D) records from the past.

A case of distinct difference between the measured blood Ethanol concentration and the concentration estimated by Widmark's equation

In the last century, several mathematical models have been developed to calculate blood ethanol concentrations (BAC) from the amount of ingested ethanol and vice versa. The most common one in the field of forensic sciences is Widmark's equation. A drinking experiment with 10 voluntary test persons was performed with a target BAC of 1.2 g/kg estimated using Widmark's equation as well as Watson's factor. The ethanol concentrations in the blood were measured using headspace gas chromatography/flame ionization and additionally with an alcohol Dehydrogenase (ADH)-based method. In a healthy 75-year-old man a distinct discrepancy between the intended and the determined blood ethanol concentration was observed. A blood ethanol concentration of 1.83 g/kg was measured and the man showed signs of intoxication. A possible explanation for the discrepancy is a reduction of the total body water content in older people. The incident showed that caution is advised when using the different mathematical models in aged people. When estimating ethanol concentrations, caution is recommended with calculated results due to potential discrepancies between mathematical models and biological systems

In-situ X-ray micro-diffraction studies of heterogeneous interfaces between cementitious materials and geological formations

In the present study the challenge of analyzing complex micro X-ray diffraction (microXRD) patterns from cement–clay interfaces has been addressed. In order to extract the maximum information concerning both the spatial distribution and the crystal structure type associated with each of the many diffracting grains in heterogeneous, polycrystalline samples, an approach has been developed in which microXRD was applied to thin sections which were rotated in the X-ray beam. The data analysis, performed on microXRD patterns collected from a filled vein of a cement–clay interface from the natural analogue in Maqarin (Jordan), and a sample from a two-year-old altered interface between cement and argillaceous rock, demonstrate the potential of this method.

Correlation between alveolar ventilation and electrical properties of lung parenchyma.

One key problem in modern medical imaging is linking measured data and actual physiological quantities. In this article we derive such a link between the electrical bioimpedance of lung parenchyma, which can be measured by electrical impedance tomography (EIT), and the magnitude of regional ventilation, a key to understanding lung mechanics and developing novel protective ventilation strategies. Two rat-derived three-dimensional alveolar microstructures obtained from synchrotron-based x-ray tomography are each exposed to a constant potential difference for different states of ventilation in a finite element simulation. While the alveolar wall volume remains constant during stretch, the enclosed air volume varies, similar to the lung volume during ventilation. The enclosed air, serving as insulator in the alveolar ensemble, determines the resulting current and accordingly local tissue bioimpedance. From this we can derive a relationship between lung tissue bioimpedance and regional alveolar ventilation. The derived relationship shows a linear dependence between air content and tissue impedance and matches clinical data determined from a ventilated patient at the bedside.

Relationship between DIAGNOdent values and sealant penetration depth on occlusal fissures

The aim of this in vitro study was to evaluate the relationship between laser fluorescence values and sealant penetration depth on occlusal fissures. One hundred and sixty-six permanent molars were selected and divided into four groups, which were each treated using a different sealant (two clear and two opaque). The teeth were independently measured twice by two experienced dentists using two laser fluorescence devices-DIAGNOdent (LF and LFpen)-before and after sealing, and then thermoclycled. After measuring, the teeth were histologically prepared and assessed for caries extension. Digital photographs of the cut sealed sites were assessed, and the sealant penetration depth was measured. All 166 sites were measured by one of the examiners taking as limits the outer and inner surface of the sealant into the fissure. For each device (LF and LFpen) and each group, the difference between the values at baseline and after sealing was plotted against the sealant penetration depth and scatter plots were provided. It could be observed that most of the points were concentrated around the zero line, for both LF and LFpen in the four groups. In conclusion, there is no relation between changes in DIAGNOdent values and increasing of depth sealant penetration within the occlusal fissures.

Spatial and functional relationships between air conduits and blood capillaries in the pulmonary gas exchange tissue of adult and developing chickens

The documented data regarding the three-dimensional structure of the air capillaries (ACs), the ultimate sites of gas exchange in the avian lung is contradictory. Further, the mode of gas exchange, described as cross-current has not been clearly elucidated. We studied the temporal and spatial arrangement of the terminal air conduits of the chicken lung and their relationship with the blood capillaries (BCs) in embryos as well as the definitive architecture in adults. Several visualization techniques that included corrosion casting, light microscopy as well as scanning and transmission electron microscopy were used. Two to six infundibulae extend from each atrium and give rise to numerous ACs that spread centrifugally. Majority of the ACs are tubular structures that give off branches, which anastomose with their neighboring cognates. Some ACs have globular shapes and a few are blind-ending tapering tubes. During inauguration, the luminal aspects of the ACs are characterized by numerous microvillus-like microplicae, which are formed during the complex processes of cell attenuation and canalization of the ACs. The parabronchial exchange BCs, initially inaugurated as disorganized meshworks, are reoriented via pillar formation to lie predominantly orthogonal to the long axes of the ACs. The remodeling of the retiform meshworks by intussusceptive angiogenesis essentially accomplishes a cross-current system at the gas exchange interface in the adults, where BCs form ring-like patterns around the ACs, thus establishing a cross-current system. Our findings clarify the mode of gas exchange in the parabronchial mantle and illuminate the basis for the functional efficiency of the avian lung.