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1.
Scand J Trauma Resusc Emerg Med ; 29(1): 46, 2021 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-33706791

RESUMO

BACKGROUND: Spinal stabilisation is recommended for prehospital trauma treatment. In Germany, vacuum mattresses are traditionally used for spinal stabilisation, whereas in anglo-american countries, long spine boards are preferred. While it is recommended that the on-scene time is as short as possible, even less than 10 minutes for unstable patients, spinal stabilisation is a time-consuming procedure. For this reason, the time needed for spinal stabilisation may prevent the on-scene time from being brief. The aim of this simulation study was to compare the time required for spinal stabilisation between a scoop stretcher in conjunction with a vacuum mattress and a long spine board. METHODS: Medical personnel of different professions were asked to perform spinal immobilizations with both methods. A total of 172 volunteers were immobilized under ideal conditions as well as under realistic conditions. A vacuum mattress was used for 78 spinal stabilisations, and a long spinal board was used for 94. The duration of the procedures were measured by video analysis. RESULTS: Under ideal conditions, spinal stabilisation on a vacuum mattress and a spine board required 254.4 s (95 % CI 235.6-273.2 s) and 83.4 s (95 % CI 77.5-89.3 s), respectively (p < 0.01). Under realistic conditions, the vacuum mattress and spine board required 358.3 s (95 % CI 316.0-400.6 s) and 112.6 s (95 % CI 102.6-122.6 s), respectively (p < 0.01). CONCLUSIONS: Spinal stabilisation for trauma patients is significantly more time consuming on a vacuum mattress than on a long spine board. Considering that the prehospital time of EMS should not exceed 60 minutes and the on-scene time should not exceed 30 minutes or even 10 minutes if the patient is in extremis, based on our results, spinal stabilisation on a vacuum mattress may consume more than 20 % of the recommended on-scene time. In contrast, stabilisation on a spine board requires only one third of the time required for that on a vacuum mattress. We conclude that a long spine board may be feasible for spinal stabilisation for critical trauma patients with timesensitive life threatening ABCDE-problems to ensure the shortest possible on-scene time for prehospital trauma treatment, not least if a patient has to be rescued from an open or inaccessible terrain, especially that with uneven overgrown land.


Assuntos
Leitos , Imobilização/métodos , Traumatismos da Coluna Vertebral , Macas , Serviços Médicos de Emergência , Feminino , Alemanha , Humanos , Imobilização/instrumentação , Masculino , Simulação de Paciente , Vácuo
2.
Opt Lett ; 30(9): 967-9, 2005 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-15906972

RESUMO

A mode-evolution-based polarization splitter suitable for high-index-contrast systems and directly integratable with a recently reported on-polarization rotator is described and its performance verified through both finite-difference time-domain and eigenmode expansion simulations. For a device length of 200 microm, greater than 22 dB of extinction is obtained across a 1.45-1.75-microm bandwidth.

3.
Opt Lett ; 30(2): 138-40, 2005 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-15675692

RESUMO

For the first time to our knowledge, designs for mode-evolution-based integrated polarization rotators requiring only a pair of waveguide core layers are presented. Finite-difference time-domain and eigenmode expansion simulations demonstrate the near-ideal performance of the approach. In contrast with approaches based on mode coupling, no significant wavelength sensitivity is observed.

4.
Opt Lett ; 27(11): 957-9, 2002 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-18026336

RESUMO

We report on the observation of quantum-limited timing jitter in a harmonically mode-locked soliton fiber laser with an ultralow-noise local oscillator. The effects of amplitude and phase modulation on the spectrum are described and compared with theory.

5.
Opt Lett ; 27(20): 1758-60, 2002.
Artigo em Inglês | MEDLINE | ID: mdl-18033354

RESUMO

We have studied a passive, harmonically mode-locked stretched-pulse erbium fiber ring laser with net positive dispersion that is self-stabilized by gain depletion and electrostriction. Periodic pulses with supermode suppression of >75 dB and picosecond jitter are achieved. The pulses are compressible to 125 fs by external chirp compensation. The repetition rate is 220 MHz, and the average power is as high as 80 mW.

6.
Opt Lett ; 27(20): 1785-7, 2002.
Artigo em Inglês | MEDLINE | ID: mdl-18033363

RESUMO

We show how an electromagnetic cavity with arbitrarily high Q and small (bounded) modal volume can be formed in two or three dimensions with a proper choice of dielectric constants. Unlike in previous work, neither a complete photonic bandgap nor a trade-off in mode localization for Q is required. Rather, scattering and radiation are prohibited by a perfect mode match of the TE-polarized modes in each subsection of a Bragg resonator. Q values in excess of 10(5) are demonstrated through finite-difference time-domain simulations of two- and three-dimensional structures with modal areas or volumes of the order of the wavelength squared or cubed.

7.
Phys Rev Lett ; 86(24): 5462-5, 2001 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-11415276

RESUMO

Nonlinear optical effects due to the phase between carrier and envelope are observed with 5 fs pulses from a Kerr-lens mode-locked Ti:sapphire laser. These sub-two-cycle pulses with octave spanning spectra are the shortest pulses ever generated directly from a laser oscillator. Detection of the carrier-envelope phase slip is made possible by simply focusing the short pulses directly from the oscillator into a BBO crystal. As a further example of nonlinear optics with such short pulses, the interference between second- and third-harmonic components is also demonstrated.

8.
Opt Express ; 8(12): 664-9, 2001 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-19421256

RESUMO

The timing jitter and frequency jitter of quantized optical pulses obey Heisenberg's uncertainty principle. We show how one jitter may be reduced at the expense of the other, using dispersion and phase modulation.

9.
Opt Lett ; 26(5): 292-4, 2001 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-18040305

RESUMO

We report the generation of 14-fs pulses at 1.3mum with 80-mW average power at 100-MHz repetition rate by an all-solid-state Kerr-lens mode-locked Cr:forsterite laser. The laser spectrum covers wavelengths of 1230-1580 nm, with a FWHM of 250 nm. Since 1.3-mum wavelengths are close to the zero dispersion wavelength of Cr:forsterite, higher-order dispersion is the main factor limiting pulse durations. We use specially designed and fabricated double-chirped mirrors in combination with high-index PBH71 prisms to compensate for the intracavity dispersion over almost 300 nm.

10.
Opt Lett ; 26(10): 669-71, 2001 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-18040414

RESUMO

We demonstrate what is to our knowledge the first all-fiber squeezing experiment. A balanced Sagnac loop is used, and a record 6.1+/-0.2dB of noise reduction below shot noise has been obtained without stabilization. A gigahertz Er-doped fiber laser and a high-power double-clad Er-Yb amplifier have been developed to suppress guided acoustic-wave Brillouin scattering and to make possible the all-fiber configuration.

11.
Opt Lett ; 26(21): 1654-6, 2001 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-18049689

RESUMO

It is shown that, in addition to the well-known phase accumulation of a traveling soliton, which may be interpreted as a change of phase velocity as a result of the Kerr nonlinearity, there is a change in the speed of travel of the envelope, the group velocity. This analysis is extended to dispersion-managed solitons, for which it is shown that the discrepancy between phase- and group-velocity changes is generally smaller.

12.
Opt Lett ; 25(1): 73-5, 2000 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-18059786

RESUMO

Strip-line pedestal antiresonant reflecting waveguides are high-confinement, silica integrated optical waveguides in which the optical modes are completely isolated from the substrate by thin high-index layers. These waveguides are particularly well suited for whispering-gallery mode excitation in high-Q microspheres. They can also be used in microphotonic circuits, such as for microring resonators. The theory and design of these structures are highlighted. Experiments that show high coupling efficiency to microspheres are also demonstrated.

13.
Opt Lett ; 25(5): 290-2, 2000 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-18059857

RESUMO

Analytical expressions are presented for Manakov solitons perturbed by polarization mode dispersion (PMD). Comparison is made with computer simulations. Dispersion-managed solitons are also studied. It is concluded that at high bit rates solitons are superior to linear return-to-zero propagation with regard to PMD.

14.
Opt Lett ; 25(8): 524-6, 2000 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-18064099

RESUMO

We demonstrate a method for spectrally shaping optical pulses that is readily reconfigurable and can produce variable filter functions. This practical technique relies on a compact and robust 3.86-m-long linearly chirped fiber Bragg grating that chromatically disperses the pulse to ~30 ns. We then shape the pulse envelope, and thus the pulse spectrum, with a programmable arbitrary waveform generator and an amplitude modulator to obtain several filter functions.

15.
Opt Lett ; 25(13): 948-50, 2000 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-18064236

RESUMO

Two-photon absorption provided by a semiconductor mirror structure is shown to reduce amplitude fluctuations significantly in a harmonically mo e-locked fiber ring laser. Pulse dropouts are eliminated in a laser that produces picosecond pulses at a repetition rate of 2 GHz.

16.
Opt Lett ; 25(19): 1418-20, 2000 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-18066234

RESUMO

We report direct generation of <500-fs pulses at a 1-GHz rate from a self-starting passively mode-locked fiber laser by regeneratively synchronizing the pulses with a phase modulator. The pulses are amplified and passed through a dispersion-decreasing fiber and a normal-dispersion supercontinuum fiber. The resulting continuum is wider than 350 nm.

17.
Opt Lett ; 25(22): 1636-8, 2000 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-18066299

RESUMO

Whispering-gallery modes in silica microspheres can be accessed very efficiently with the recently introduced stripline pedestal antiresonant reflecting optical waveguide (SPARROW) structure. This integrated-optics coupling technique creates novel application opportunities for the high-Q spherical cavities. We report the demonstration of a narrow-band wavelength-drop configuration utilizing SPARROW waveguides and a silica microsphere.

18.
Chaos ; 10(3): 529-538, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-12779403

RESUMO

The effect of polarization mode dispersion (PMD) on Manakov solitons and dispersion managed solitons is treated analytically and by numerical simulation. In the analytic approach the internal motion of the Manakov soliton is represented as a damped harmonic oscillator. The PMD functions as a white noise source driving the oscillations. It is shown that the solitons can withstand PMD up to a certain instability threshold for which an analytic expression is obtained. This threshold is also evaluated for dispersion managed solitons. (c) 2000 American Institute of Physics.

19.
Opt Lett ; 24(4): 217-9, 1999 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-18071459

RESUMO

We study collisions in dispersion-managed soliton propagation for wavelength-division multiplexing application at zero net dispersion when the Gordon-Haus timing jitter is removed. We show that the collisions can lead to group-velocity changes and spectral collapse. Large channel separation ameliorates the effects. Filters prevent spectral collapse but do not affect the velocity changes.

20.
Opt Lett ; 24(6): 411-3, 1999 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-18071523

RESUMO

Pulses shorter than two optical cycles with bandwidths in excess of 400 nm have been generated from a Kerr-lens mode-locked Ti:sapphire laser with a repetition rate of 90 MHz and an average power of 200 mW. Low-dispersion prisms and double-chirped mirrors provide broadband controlled dispersion and high reflectivity. These pulse durations are to our knowledge the shortest ever generated directly from a laser oscillator.

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