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Introduction: Testicular torsion is a time sensitive condition for which there can be significant delays to surgery or transfer to definitive care while trying to obtain an ultrasound to confirm the diagnosis. This study determines the test characteristics for each individual sonographic sign of testicular torsion associated with the patient requiring surgical intervention. Methods: A retrospective health records review of adult patients with acute, non-traumatic scrotal pain or swelling (defined as under 24 hours since onset) presenting to one of two Canadian academic tertiary care emergency departments between November 2009 and March 2013 was performed. A single data abstractor completed a case report form for each patient including demographics, individual ultrasound findings, final diagnosis, and need for surgical intervention. The sensitivity and specificity of each ultrasonographic sign (including testicular heterogeneity, decreased colour doppler, and decreased pulsed wave doppler) at predicting surgical intervention during the same hospital visit was calculated along with 95% confidence intervals. Results: During the study period there were a total of 876 emergency department visits for scrotal pain, of which 198 patients met our inclusion criteria. The included patients had a mean age of 36.2 years. Decreased blood flow to the painful testicle on colour doppler showed the best overall test characteristics with a sensitivity of 82.4% (95% CI 55.8%-95.3%) and specificity of 100% (95% CI 96.3%-100%) for predicting a need for surgical intervention for testicular torsion. Other ultrasound findings for testicular torsion included a heterogeneous appearance of the painful testicle (sensitivity 47.1% [95% CI 23.9%-71.5%], specificity 77.4% [95% CI 68.9%-84.2%]), and decreased arterial or venous flow on pulsed wave doppler (sensitivity 76.5% [95% CI 49.8%-92.1%], specificity 100% [95% CI 96.3%-100%]). Conclusion: Decreased blood flow to the painful testicle on colour doppler showed excellent specificity and can rapidly “rule-in” a need for surgical intervention for testicular torsion. Given that colour doppler is relatively easy to learn and perform, future studies should assess the use of colour doppler using point of care ultrasound to expedite surgical consultation.
This paper reports on the status of the PHELIX petawatt laser which is
built at the Gesellschaft fuer Schwerionenforschung (GSI) in close
collaboration with the Lawrence Livermore National Laboratory (LLNL), and
the Commissariat à l'Energie Atomique (CEA) in France. First
experiments carried out with the chirped pulse amplification (CPA)
front-end will also be briefly reviewed.
The Petawatt laser at Lawrence Livermore National
Laboratory (LLNL) has opened a new regime of laser matter
interactions in which the quiver motion of plasma electrons
is fully relativistic with energies extending well above
the threshold for nuclear processes. In addition to ∼few
MeV ponderomotive electrons produced in ultra intense laser-solid
interactions, we have found a high energy component of
electrons extending to ∼100 MeV apparently from relativistic
selffocusing and plasma acceleration in the underdense
preformed plasma. The generation of hard bremsstrahlung,
photonuclear reactions, and preliminary evidence for positron-electron
pair production will be discussed.
AGL15 (AGAMOUS-like 15) was originally identified as a sequence preferentially expressed in developing plant embryos by comparing PCR-generated ‘differential displays’ of embryo and non-embryo RNA populations. The sequence is expressed at low levels and encodes a member of the MADS domain family (named for the first four members to be identified: MCM1, AGAMOUS, DEFICIENS, and SERUM RESPONSE FACTOR) of regulatory factors. Members of the MADS domain family play pivotal roles in critical developmental events in a wide variety of organisms: in specification of mating type in yeast (MCM1), in responses to the environment in human cells (SRF), in control of mesoderm differentiation in Drosophila and muscle differentiation in humans (MEF2), and in determination of meristem and organ identity during flower development in plants (AGAMOUS, DEFICIENS/APETALA3, GLOBOSA/PISTILLATA, etc.). AGL15 is the only MADS domain factor identified to date that is expressed in a highly preferential manner in plant embryos.
We present the results of experimental studies of the strain effects on the excitonic transitions in GaN epitaxial layers on sapphire and SiC substrates. Photoluminescence and reflectance spectroscopies were performed to measure the energy positions of exciton transitions and X-ray diffraction measurements were conducted to examine the lattice parameters of GaN epitaxial layers grown on different substrates. Residual strain induced by the mismatch of lattice constants and thermal-expansion between GaN epitaxial layers and substrates was found to have a strong influence in determining the energies of excitonic transitions. The overall effects of the strain generated in GaN is compressive for GaN grown on sapphire and tensile for GaN on SiC substrate. The uniaxial and hydrostatic deformation potentials of wurtzite GaN were derived from the experimental results. Our results yield the uniaxial deformation potentials b1≈−5.3 eV and b2≈2.7 eV, as well as the hydrostatic components a1≈−6.5 eV and a2≈−11.8 eV.
Photoluminescence (PL) and optically-detected magnetic resonance (ODMR) experiments have been performed on undoped GaN epitaxial layers grown on 6H-SiC substrates. The defects observed in these films are compared with those found from previous ODMR studies of undoped GaN layers grown on sapphire substrates. Strong, sharp donor-bound exciton bands at 3.46 -3.47 eV and weak, broad emission bands at 2.2 eV were observed from several 0.7 and 2.6 μm-thick films. In addition, fairly strong shallow donor - shallow acceptor (SD-SA) recombination with a zero-phonon-line at 3.27 eV was found for GaN layers less than 1 μm-thick. The first observation of magnetic resonance on this SD-SA recombination from undoped GaN is reported in this work. Two magnetic resonance features attributed to effective-mass (EM) and deep-donor (DD) states were detected on the 2.2 eV emission bands from all the GaN/6H-SiC films. These resonances were observed previously on similar emission from undoped GaN layers grown on sapphire substrates. The same EM donor resonance, though much weaker, was also found on the SD-SA recombination. However, a resonance associated with shallow acceptor states was not observed on this emission. The weakness of the donor resonance arises from the weak spin-dependence of the recombination mechanism involving spin-thermalized shallow acceptors. The absence of an EM acceptor is due to the broadening of the resonance through the spreading of the acceptor g-values by random strains in these films.
Monocrystalline AlxGa1−xN(0001) (0.05 ≤ x ≤ 0.70) thin films, void of oriented domain structures and associated low-angle grain boundaries, have been grown at high temperatures via OMVPE directly on vicinal and on-axis α(6H)-SiC(0001) wafers using TEG, TEA and ammonia in a cold-wall, vertical, pancake-style reactor. The surface morphologies were smooth and die densities and distributions of dislocations were comparable to that observed in GaN(0001) films grown on high temperature A1N buffer layers. Double-crystal XRC measurements showed a FWHM value as low as 186 arc sec for the (0002) reflection. Spectra obtained via CL showed strong near band-edge emissions with FWHM values as low as 31 meV. The compositions of the AlxGa1−xN films were determined using EDX, AES and RBS and compared to the values of the bandgap as measured by spectral ellipsometry and CL emissions. A negative bowing parameter was found. Controlled n-type, Si-doping of AlxGa1−xN for x ≤ 0.4 has been achieved with net carrier concentrations ranging from ≈ 2 × 1017 cm−3 to 2 × 1019 cm−3. Acceptor doping with Mg for x < 0.13 was also successful.
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