589 research outputs found
Synchrotron based planar imaging and digital tomosynthesis of breast and biopsy phantoms using a CMOS active pixel sensor
The SYRMEP (SYnchrotron Radiation for MEdical Physics) beamline at Elettra is performing the first mammography study on human patients using free-space propagation phase contrast imaging. The stricter spatial resolution requirements of this method currently force the use of conventional films or specialized computed radiography (CR) systems. This also prevents the implementation of three-dimensional (3D) approaches. This paper explores the use of an X-ray detector based on complementary metal-oxide-semiconductor (CMOS) active pixel sensor (APS) technology as a possible alternative, for acquisitions both in planar and tomosynthesis geometry.Results indicate higher quality of the images acquired with the synchrotron set-up in both geometries. This improvement can be partly ascribed to the use of parallel, collimated and monochromatic synchrotron radiation (resulting in scatter rejection, no penumbra-induced blurring and optimized X-ray energy), and partly to phase contrast effects. Even though the pixel size of the used detector is still too large - and thus suboptimal - for free-space propagation phase contrast imaging, a degree of phase-induced edge enhancement can clearly be observed in the images
Incidence of post myocardial infarction left ventricular thrombus formation in the era of primary percutaneous intervention and glycoprotein IIb/IIIa inhibitors. A prospective observational study
BACKGROUND: Before the widespread use of primary percutaneous coronary intervention (PCI) and glycoprotein IIb/IIIa inhibitors (GP IIb/IIIa) left ventricular (LV) thrombus formation had been reported to complicate up to 20% of acute myocardial infarctions (AMI). The incidence of LV thrombus formation with these treatment modalities is not well known. METHODS: 92 consecutive patients with ST-elevation AMI treated with PCI and GP IIb/IIIa inhibitors underwent 2-D echocardiograms, with and without echo contrast agent, within 24–72 hours. RESULTS: Only 4/92 (4.3%) had an LV thrombus, representing a significantly lower incidence than that reported in the pre-PCI era. Use of contrast agents did not improve detection of LV thrombi in our study. CONCLUSION: The incidence of LV thrombus formation after acute MI, in the current era of rapid reperfusion, is lower than what has been historically reported
Carboxylic ester hydrolases from hyperthermophiles
Carboxylic ester hydrolyzing enzymes constitute a large group of enzymes that are able to catalyze the hydrolysis, synthesis or transesterification of an ester bond. They can be found in all three domains of life, including the group of hyperthermophilic bacteria and archaea. Esterases from the latter group often exhibit a high intrinsic stability, which makes them of interest them for various biotechnological applications. In this review, we aim to give an overview of all characterized carboxylic ester hydrolases from hyperthermophilic microorganisms and provide details on their substrate specificity, kinetics, optimal catalytic conditions, and stability. Approaches for the discovery of new carboxylic ester hydrolases are described. Special attention is given to the currently characterized hyperthermophilic enzymes with respect to their biochemical properties, 3D structure, and classification
Search for Gravitational Waves from Primordial Black Hole Binary Coalescences in the Galactic Halo
We use data from the second science run of the LIGO gravitational-wave
detectors to search for the gravitational waves from primordial black hole
(PBH) binary coalescence with component masses in the range 0.2--.
The analysis requires a signal to be found in the data from both LIGO
observatories, according to a set of coincidence criteria. No inspiral signals
were found. Assuming a spherical halo with core radius 5 kpc extending to 50
kpc containing non-spinning black holes with masses in the range 0.2--, we place an observational upper limit on the rate of PBH coalescence
of 63 per year per Milky Way halo (MWH) with 90% confidence.Comment: 7 pages, 4 figures, to be submitted to Phys. Rev.
Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector
Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente
Gender differences in coerced patients with schizophrenia
European Commission (Quality of life and
Management of Living Resources Programme, contract number QLG4-CT-
2002-01036), Czech Ministry of Education research grant MSM002160849,
and research grants PRVOUK–P26/LF1/4 and PRVOUK–P03/LF1/
Respectful leadership:Reducing performance challenges posed by leader role incongruence and gender dissimilarity
We investigate how respectful leadership can help overcome the challenges for follower performance that female leaders face when working (especially with male) followers. First, based on role congruity theory, we illustrate the biases faced by female leaders. Second, based on research on gender (dis-)similarity, we propose that these biases should be particularly pronounced when working with a male follower. Finally, we propose that respectful leadership is most conducive to performance in female leader–male follower dyads compared with all other gender configurations. A multi-source field study (N = 214) provides partial support for our hypothesis. While our hypothesized effect was confirmed, respectful leadership seems to be generally effective for female leaders irrespective of follower gender, thus lending greater support in this context to the arguments of role congruity rather than gender dissimilarity
Laparoscopic versus open splenectomy for nontraumatic diseases
BACKGROUND: Laparoscopic splenectomy (LS) is the standard procedure for normal size or moderately enlarged spleens; open splenectomy (OS) is preferred in cases of splenomegaly. In this study, indications for and complications of open and laparoscopic splenectomy were analyzed, with the aim to identify patients who will benefit from either technique. METHOD: A consecutive series of 52 patients undergoing elective open or laparoscopic splenectomy between January 2001 and December 2006 was analyzed. Spleen volume was calculated as length x width x depth from the pathologist's measurements. RESULTS: LS was performed in 25 patients with a median age of 41 years (range = 24-65). OS was performed in 27 patients with a median age of 60 years (range = 24-86) (p < 0.001). Conversion to OS was necessary in two patients (8%). Operation time was significantly shorter in LS (p < 0.05). Spleen volume was significantly greater in patients who underwent open (median = 2520 ml, range = 150-16,800 ml) versus laparoscopic (median = 648 ml, range = 150-4860 ml) splenectomy (p = 0.001). In 36% of all laparoscopic procedures, spleen volume exceeded 1000 ml. The underlying disease was mainly immunothrombocytopenia in LS patients and lymphoma and osteomyelofibrosis in OS patients. Five patients died after OS. Significantly more patients were hospitalized longer than 7 days following OS than following LS (p < 0.05). Overall complication rate was higher after OS (LS, 8; OS, 13 patients; p < 0.05). CONCLUSIONS: LS was preferred in younger patients with moderate splenomegaly, while massive splenomegaly mostly led to OS. In view of the absence of technique-related differences, LS can primarily be attempted in all patients
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