Periosteal Ewing's Sarcoma: Report of Two New Cases and Review of the Literature

Background. The origin of Ewing's sarcoma in a periosteal location is rare and not clearly documented. Other malignant bone tumors appear to have a somewhat better prognosis when confined between periosteum and bone. Is it the same for periosteal Ewing's sarcoma

Endovascular treatment of an open cervical fracture with carotid artery tear

The dilemma of how to treat penetrating wound injuries to the neck, which involve a combination of a common carotid artery rupture and a cervical spinal fracture, is presented in this case report

Rationale, design and clinical performance of the Superion® Interspinous Spacer: a minimally invasive implant for treatment of lumbar spinal stenosis.

Lumbar spinal stenosis is a progressive degenerative condition that manifests as low back pain with neurogenic claudication as a cardinal clinical feature. Although mild radicular symptoms can often be successfully treated with conservative care, management of lumbar spinal stenosis grows increasingly difficult as symptoms worsen. No satisfactory nonsurgical treatments exist to manage moderate radicular symptoms and, therefore, these patients are faced with the decision of continuing ineffective conservative options or opting to undergo invasive decompressive spine surgery. The Superion(®) Interspinous Spacer (Vertiflex, Inc., CA, USA) was developed specifically to fill the therapeutic void between conservative care and surgical decompression. The Superion device is a titanium implant that is delivered percutaneously and deployed between the spinous processes at the symptomatic vertebral levels. The Superion device improves radicular symptoms by limiting spinal extension and, consequently, minimizing impingement of neural and vascular elements. This article describes the rationale for and the design of the Superion device and summarizes initial clinical results with this novel, minimally invasive interspinous spacer

Temperature Dependence of the Excited-State Proton-Transfer Reaction of Quinone-cyanine‑7

Steady-state and time-resolved fluorescence techniques were used to study the temperature dependence of the photoprotolytic process of quinone-cyanine-7 (QCy7), a very strong photoacid, in H₂O and D₂O ice, over a wide temperature range, 85–270 K. We found that the excited-state proton-transfer (ESPT) rate to the solvent decreases as the temperature is lowered with a very low activation energy of 10.5 ± 1 kJ/mol. The low activation energy is in accord with free-energy-correlation theories that predict correlation between Δ<i>G</i> of reaction and the activation energy. At very low temperatures (<i>T</i> < 150 K), we find that the emission band of the RO^–*, the deprotonated form of QCy7, is blue-shifted by ∼1000 cm^–1. We attributed this band to the RO^–*···H₃O⁺ ion pair that was suggested to be an intermediate in the photoprotolytic process but has not yet been identified spectroscopically

Excited-State Proton Transfer from Quinone-Cyanine 9 to Protic Polar-Solvent Mixtures

Steady-state and time-resolved emission techniques were used to study the excited-state proton-transfer (ESPT) process of quinone cyanine 9 (QCy9) in solvent mixtures. We found that the ESPT rate from QCy9 in water/methanol mixtures is independent of the mixture composition and the rate constant is <i>k</i>_PT ∼ 10¹³ s^–1. In ethanol/trifluoroethanol (TFE) mixtures the ESPT rate strongly depends on the solvent-mixture composition. We observe two ESPT rates rather than one over a wide range of solvent-mixture compositions. The average ESPT rate decreases as the mole fraction of TFE increases

Ultrafast Excited-State Proton Transfer to the Solvent Occurs on a Hundred-Femtosecond Time-Scale

Steady-state and ultrafast time-resolved techniques were used to study a newly synthesized photoacid, phenol-carboxyether dipicolinium cyanine dye, QCy9. We found that the excited-state proton transfer (ESPT) to water occurs at the remarkably short time of about 100 fs, <i>k</i>_PT ≈ 1 × 10¹³ s^–1, the fastest rate reported up to now. On the basis of the Förster-cycle, the p<i>K</i>_a* value is estimated to be −8.5 ± 0.4. In previous studies, we reported the photoacidity of another superphotoacid, the QCy7 for which we found an ESPT rate constant of ∼1.25 × 10¹² s^–1, one-eighth that of the QCy9 compound. We found a kinetic isotope effect of the ESPT of about two