Endoscopic transorbital approach for the removal of a frontal lobe foreign body: a case report.

Low-velocity orbital penetrating injuries may result in an intracranial retained foreign body that requires surgical removal. We describe the endoscopic transorbital removal of a retained umbrella tip in the frontal lobe, which was secondary to trauma to the orbital roof. This technique facilitated the complete removal of the foreign body without causing additional damage to the surrounding tissue.

Giant metastatic mixed-type spinal ependymoma presenting with hydrocephalus.

Ependymomas are rare nervous system tumors that can arise anywhere in the neuraxis. While having a high propensity for leptomeningeal dissemination, retrograde dissemination (from the spine to the CNS) remains infrequent. We describe the case of a 31-year-old female who presented with hydrocephalus secondary to an intracranial leptomeningeal metastasis of a giant spinal ependymoma with mixed (classic and myxopapillary) histopathologic features, successfully treated with surgical resection and radiotherapy of the entire neuraxis.

Neodymium laser-pumped ultra-low noise tunable Brillouin fiber laser around 920 nm.

We have developed an ultra-low noise tunable Brillouin fiber laser exhibiting three orders of magnitude better frequency noise performance than the Neodymium-doped fiber laser pump and remarkable optical signal-to-noise ratio exceeding 80 dB suitable for immediate applications in coherent nonlinear conversion, quantum computing and underwater communications. In addition, we have implemented a custom optical phase-locked loop to ensure long-term stable operation and have investigated its impact on frequency noise. We demonstrate the power scalability of the single frequency (Hz-class) Brillouin laser, delivering over 500 mW with tunability across the 900 nm to 930 nm range in an all-fiber fully polarization-maintaining architecture.

Watt-level deep-UV subnanosecond laser system based on Nd-doped fiber at 229 nm.

We report an efficient deep-UV master-oscillator power amplifier (MOPA) laser system at 229 nm that generates 350 ps pulses at 2 MHz repetition rate with an average power of 1.2 W. The use of a polarization-maintaining large mode area neodymium-doped fiber operating on the F→I transition allows high-power laser emission of up to 28 W near 915 nm in the sub-nanosecond regime with low spectral broadening.

Mode-locked all-PM Nd-doped fiber laser near 910 nm.

We present a compact passively mode-locked fiber laser emitting near 910 nm with an all-polarization-maintaining fiber laser architecture. The ring-cavity laser configuration includes a core-pumped neodymium-doped fiber as a gain medium and a semiconductor saturable absorber mirror as a passive mode-locking element. A bandpass filter is used to suppress parasitic emission near 1.

Linearly-polarized pulsed Nd-doped fiber MOPA at 905 nm and frequency conversion to deep-UV at 226 nm.

We present the first frequency-quadrupled linearly-polarized Q-switched neodymium-doped fiber laser generating > 500 mW average power at 226 nm. For this purpose, an amplified Q-switched oscillator using novel large-mode-area (LMA) fibers and generating up to 24 W average power (15 kW peak power) at 905 nm was developed. Two nonlinear frequency conversion stages using a LBO crystal for SHG and a BBO crystal for FHG generate respectively up to 4.

Tm and Ho colasing in in-band pumped waveguides fabricated by femtosecond laser writing.

We report on the first, to the best of our knowledge, in-band pumped , codoped waveguide (WG) laser. A depressed-index surface channel WG (type III) with a 50 µm half-ring cladding is fabricated in a 5 at. % , 0.

Incidence and characteristics of cerebral hypoxia after craniectomy in brain-injured patients: a cohort study.

Objective: After craniectomy, although intracranial pressure (ICP) is controlled, episodes of brain hypoxia might still occur. Cerebral hypoxia is an indicator of poor outcome independently of ICP and cerebral perfusion pressure. No study has systematically evaluated the incidence and characteristics of brain hypoxia after craniectomy.

Widely tunable in-band-pumped Tm:CaF laser.

This Letter presents the efficient laser operation of a : crystal in-band pumped at 1610 nm by an Er-Yb-codoped fiber laser system. A laser slope efficiency of 55% (versus incident pump power) was achieved in a continuous-wave regime, with a maximum output power of 1.25 W at ∼1.

Ultrafast laser inscribed waveguide lasers in Tm:CALGO with depressed-index cladding.

Depressed-index buried and surface channel waveguides (type III) are produced in a bulk 3.5 at.% Tm:CALGO crystal by femtosecond direct-laser-writing at kHz repetition rate.

Dissipative soliton resonance in a mode-locked Nd-fiber laser operating at 927 nm.

We demonstrate for the first time, to our knowledge, an all-polarization-maintaining double-clad neodymium fiber laser operating in the dissipative soliton resonance (DSR) regime where stable mode-locking is achieved using a nonlinear amplifying loop mirror (NALM) with large normal dispersion in a figure-8 cavity design. The laser thereby generates square-shaped nanosecond pulses whose duration linearly scales with pump power from 0.5 up to 6 ns, with a maximum energy of 20 nJ.

In-band pumping of Tm:LiYF channel waveguide: a power scaling strategy for ∼2 μm waveguide lasers.

We report on a novel power scaling strategy for thulium waveguide (WG) lasers relying on in-band pumping by high-brightness Raman fiber lasers (RFLs) and the use of liquid-phase-epitaxy-grown fluoride crystalline thin films for better thermal management. Thulium channel WGs are produced by microstructuring the Tm:LiYF/LiYF epitaxies via diamond-saw dicing. They are pumped by a RFL based on an erbium master oscillator power amplifier and a GeO-doped silica fiber and emit polarized output at 1679 nm.

Minimal PaO2 threshold after traumatic brain injury and clinical utility of a novel brain oxygenation ratio.

Objective: Avoiding decreases in brain tissue oxygenation (PbtO2) after traumatic brain injury (TBI) is important. How best to adjust PbtO2 remains unclear. The authors investigated the association between partial pressure of oxygen (PaO2) and PbtO2 to determine the minimal PaO2 required to maintain PbtO2 above the hypoxic threshold (> 20 mm Hg), accounting for other determinants of PbtO2 and repeated measurements in the same patient.

7.5 W blue light generation at 452 nm by internal frequency doubling of a continuous-wave Nd-doped fiber laser.

We present the first frequency-doubled neodymium-doped fiber laser generating multi-watt CW power near 450 nm. A bow-tie resonator incorporating a LBO nonlinear crystal is integrated within a Nd-doped fiber laser emitting near 900 nm. This scheme achieves an IR to blue conversion efficiency close to 55% without any active control of the internal resonant cavity.

2.3 μm Tm:YLF mode-locked laser.

A passively mode-locked Tm:YLF laser emitting at 2.3 μm is reported for the first time, to the best of our knowledge. The continuous-wave stable mode-locking operation is obtained with a semiconductor saturable absorber mirror at a repetition rate of 100 MHz.

Transverse mode selection in a Nd-doped fiber amplifier at 910 nm.

Selective amplifications of LP fundamental mode and higher order modes LP and LP are demonstrated in a double-pass Nd-doped LMA fiber amplifier operating at 910 nm. A multimode core fiber Bragg grating is employed to select a single guided mode by simply adjusting the wavelength of the seed signal. Although the M parameter of the output beam from the amplifier was ~2.

Risk of Delayed Intracranial Hemorrhage in Anticoagulated Patients with Mild Traumatic Brain Injury: Systematic Review and Meta-Analysis.

Background: Delayed intracranial hemorrhage is a potential complication of head trauma in anticoagulated patients.

Objective: Our aim was to use a systematic review and meta-analysis to determine the risk of delayed intracranial hemorrhage 24 h after head trauma in patients who have a normal initial brain computed tomography (CT) scan but took vitamin K antagonist before injury.

Methods: EMBASE, Medline, and Cochrane Library were searched using controlled vocabulary and keywords.

Mode-locked Nd-doped fiber laser at 930 nm.

We report on a passively mode-locked neodymium-doped oscillator featuring a W-type fiber operating at 930 nm. Two different laser configurations with and without dispersion management are investigated to generate high-energy similaritons. Chirped pulses with 2.

Safety and efficacy of CHOP for treatment of diffuse large B-cell lymphoma with different combination antiretroviral therapy regimens: SCULPT study.

Background: Use of combination antiretroviral therapy (cART) and cyclophosphamide, doxorubicin, vincristine and prednisone (CHOP) with or without rituximab for treatment of diffuse large B-cell lymphoma (DLBCL) in HIV substantially increases response rates but may also increase toxicity, possibly due to antiretroviral-antineoplastic drug interactions. The objective of this study was to evaluate the frequency of complete remission (CR) of DLBCL in patients treated with CHOP while receiving a protease inhibitor (PI) versus a non-PI-based cART.

Methods: A retrospective multicentre pilot study was conducted in HIV-infected patients on cART treated for DLBCL with CHOP between 2002-2010 in three academic hospitals.

Coagulopathy after traumatic brain injury.

Traumatic brain injury has long been associated with abnormal coagulation parameters, but the exact mechanisms underlying this phenomenon are poorly understood. Coagulopathy after traumatic brain injury includes hypercoagulable and hypocoagulable states that can lead to secondary injury by either the induction of microthrombosis or the progression of hemorrhagic brain lesions. Multiple hypotheses have been proposed to explain this phenomenon, including the release of tissue factor, disseminated intravascular coagulation, hyperfibrinolysis, hypoperfusion with protein C activation, and platelet dysfunction.

Surgical management of blood blister-like aneurysms of the internal carotid artery.

Objective: To present a review of the literature and a case series of blood blister-like aneurysms (BBA) to show that an adapted direct surgical approach enables treatment of BBA with a low complication rate.

Methods: A retrospective review was performed of patients treated for a ruptured BBA of the internal carotid artery (ICA) at Hôpital Notre-Dame from 2005-2009. Clinicoradiologic data and intraoperative videos were analyzed.

Dynamical amplification of phase conjugation using a modulated optical feedback in a Nd:YVO4 laser.

We demonstrate an efficient dynamical amplification of phase conjugation in the gain medium of a diode-pumped Nd(3+)YVO4 solid-state laser via excitation of its relaxation oscillations. Consequently, enhancement in the modulated amplitude of the phase conjugate wave is observed with up to +30 dB compared to the classical homodyne approach.

Endoscopic treatment of distal choroidal artery aneurysm.

Distal choroidal artery aneurysms stemming from the lateral wall of the ventricles are rare and are mostly associated with moyamoya disease. The treatment of these aneurysms is difficult because of their deep location. The authors report the case of a 50-year-old woman followed for moyamoya disease presenting with 2 intraventricular hemorrhages.

Generation of picosecond blue light pulses at 464 nm by frequency doubling an Nd-doped fiber based Master Oscillator Power Amplifier.

We demonstrate 308 mW of single-mode laser emission at 464 nm from a frequency doubled picosecond fiber based Master Oscillator Power Amplifier (MOPA). The laser system consisted of a gain-switched and spectrally narrowed Fabry-Perot laser diode emitting at 928 nm, which was amplified in a two-stage amplifier based on W-type double-clad Nd-doped fibers. Output pulses with a duration of 90 ps at a repetition rate of 41 MHz were frequency-doubled in a periodically poled MgO-doped Congruent Lithium Niobate.