7,768 research outputs found
Parametric Amplification and Back-Action Noise Squeezing by a Qubit-Coupled Nanoresonator
We demonstrate the parametric amplification and noise squeezing of nanomechanical motion utilizing dispersive coupling
to a Cooper-pair box qubit. By modulating the qubit bias and resulting mechanical resonance shift, we achieve gain of 30 dB and
noise squeezing of 4 dB. This qubit-mediated effect is 3000 times more effective than that resulting from the weak nonlinearity of
capacitance to a nearby electrode. This technique may be used to prepare nanomechanical squeezed states
Correlation between fracture surface morphology and toughness in Zr-based bulk metallic glasses
Fracture surfaces of Zr-based bulk metallic glasses of various compositions tested in the as-cast and annealed conditions were analyzed using scanning electron microscopy. The tougher samples have shown highly jagged patterns at the beginning stage of crack propagation, and the length and roughness of this jagged pattern correlate well with the measured fracture toughness values. These jagged patterns, the main source of energy dissipation in the sample, are attributed to the formation of shear bands inside the sample. This observation provides strong evidence of significant āplastic zoneā screening at the crack tip
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Complete response of skull base inverted papilloma to chemotherapy: Case report.
BackgroundInverted papilloma (IP) is the most common benign sinonasal neoplasm. Endoscopic techniques, improved understanding of pathophysiology, and novel surgical approaches have allowed rhinologists to treat IPs more effectively, with surgery being the mainstay of therapy. Frontal sinus IP poses a challenge for surgical therapy due to complex anatomy and potentially difficult surgical access.ObjectivesWe reported a unique case of a massive frontal sinus IP that presented with intracranial and orbital extension, with near resolution after chemotherapy.MethodsA retrospective case review of a patient with a frontal sinus IP treated at a tertiary academic medical center.ResultsA 75-year-old male patient presented with nasal obstruction, purulent nasal discharge, and a growing left supraorbital mass. Endoscopy demonstrated a mass that filled both frontal and ethmoid sinuses, with orbital invasion. There also was substantial erosion of the posterior table, which measured 1.73 Ć 1.40 cm. A biopsy specimen demonstrated IP with carcinoma in situ. The patient was deemed unresectable on initial evaluation and, subsequently, underwent chemotherapy (carboplatin and paclitaxel). The tumor had a dramatic response to chemotherapy, and the patient elected for definitive surgery to remove any residual disease. During surgery, only a small focus of IP was found along the superior wall of the frontal sinus. No tumor was found elsewhere, including at the site of skull base erosion. The final pathology was IP without carcinoma in situ or dysplasia.ConclusionThis was the first reported case of chemotherapeutic "debulking" of IP, which facilitated surgical resection, despite substantial intracranial and orbital involvement. Although nearly all IPs can be treated surgically, rare cases, such as unresectable tumors, may benefit from systemic chemotherapy
Fracture toughness and crack-resistance curve behavior in metallic glass-matrix composites
Nonlinear-elastic fracture mechanics methods are used to assess the fracture toughness of bulk metallic glass (BMG) composites; results are compared with similar measurements for other monolithic and composite BMG alloys. Mechanistically, plastic shielding gives rise to characteristic resistance-curve behavior where the fracture resistance increases with crack extension. Specifically, confinement of damage by second-phase dendrites is shown to result in enhancement of the toughness by nearly an order of magnitude relative to unreinforced glass
Incidental finding of lymphoma after septoplasty.
IntroductionSeptoplasty, or surgical correction of the deviated septum, is an elective, routinely performed rhinologic procedure to address nasal airway obstruction. In many cases, resected septal cartilage and bone fragments are sent for pathologic review, although there is no consensus on this practice. We reported two cases of incidentally diagnosed lymphoma after elective septoplasty and discussed clinical presentation, diagnosis, and management.MethodsRetrospective chart review of two patients who underwent septoplasty at a tertiary academic medical center and found to have incidental lymphoma based on histopathology.ResultsTwo patients who underwent septoplasty had an incidental diagnosis of lymphoma on pathologic analysis. One patient was noted to have an S-shaped septal deviation that produced bilateral nasal obstruction. She underwent a difficult septoplasty, in which the mucoperichondrial flap was firmly adherent to the underlying septum and bone. Final pathology demonstrated diffuse large B-cell lymphoma. She was treated with chemoradiation and remained free of disease at 59 months. The other patient had a history of nasal trauma, which produced left septal deviation. He underwent an uncomplicated septoplasty, with pathology that demonstrated low-grade B-cell lymphoma. Because there was no evidence of active disease, the decision was made to not treat and to observe the patient clinically.ConclusionsThis is the first reported series of septal lymphoma incidentally diagnosed on routine septoplasty. Although histopathologic review of specimens from routine nasal and sinus surgery is not routinely performed, this report highlighted the importance of this process, on a case-by-case basis, in detecting unexpected malignancies that otherwise were clinically silent
Spin Dynamics in the LTT Phase of ~1/8 Doped Single Crystal La_{1.67}Eu_{0.2}Sr_{0.13}CuO_4
We present La and Cu NMR relaxation measurements in single crystal
La_{1.67}Eu_{0.2}Sr_{0.13}CuO_4. A strong peak in the La spin-lattice
relaxation rate observed in the spin ordered state is well-described by the BPP
mechanism[1] and arises from continuous slowing of electronic spin fluctuations
with decreasing temperature; these spin fluctuations exhibit XY-like anisotropy
in the ordered state. The spin pseudogap is enhanced by the static
charge-stripe order in the LTT phase.Comment: Four pages, three figure
PDB41 Productivity Loss Costs Attributable to Obesity in Working Patients with Diabetes in the US
An Over-Massive Black Hole in a Typical Star-Forming Galaxy, 2 Billion Years After the Big Bang
Supermassive black holes (SMBHs) and their host galaxies are generally
thought to coevolve, so that the SMBH achieves up to about 0.2 to 0.5% of the
host galaxy mass in the present day. The radiation emitted from the growing
SMBH is expected to affect star formation throughout the host galaxy. The
relevance of this scenario at early cosmic epochs is not yet established. We
present spectroscopic observations of a galaxy at redshift z = 3.328, which
hosts an actively accreting, extremely massive BH, in its final stages of
growth. The SMBH mass is roughly one-tenth the mass of the entire host galaxy,
suggesting that it has grown much more efficiently than the host, contrary to
models of synchronized coevolution. The host galaxy is forming stars at an
intense rate, despite the presence of a SMBH-driven gas outflow.Comment: Author's version, including the main paper and the Supplementary
Materials (16+21 pages, 3+3 figures
Study of the neutron star structure in strong magnetic fields including the anomalous magnetic moments
We study the effects of strong magnetic fields on the neutron star structure.
If the interior field of a star is on the same order of the surface field
currently observed, the influences of the magnetic field on the star mass and
radius are negligible. If one assumes that the internal magnetic field can be
as large as that estimated from the scalar virial theorem, considerable effects
can be induced. The maximum mass of stars is arisen substantially while the
central density is largely suppressed. For two equal-mass stars the radius of
the magnetic star can be larger by about 10% 20% than the nonmagnetic
star.Comment: 26 pages, 5 postscript figures; replaced by the revised version,
Chin. J. Astron. Astrophys., accepte
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