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  • 1
    In: Clinical Orthopaedics & Related Research, Ovid Technologies (Wolters Kluwer Health), Vol. 481, No. 7 ( 2023-07), p. 1399-1411
    Abstract: Ankylosing spondylitis–related cervical spine fracture with neurologic impairment (ASCF-NI) is a rare but often lethal injury. Factors independently associated with survival after treatment remain poorly defined, and identifying patients who are likely to survive the injury remains challenging. Questions/purposes (1) What factors are independently associated with survival after treatment among patients with ASCF-NI? (2) Can a nomogram be developed that is sufficiently simple for clinicians to use that can identify patients who are the most likely to survive after injury? Methods This retrospective study was conducted based on a multi-institutional group of patients admitted and treated at one of 29 tertiary hospitals in China between March 1, 2003, and July 31, 2019. A total of 363 patients with a mean age of 53 ± 12 years were eventually included, 343 of whom were male. According to the National Household Registration Management System, 17% (61 of 363) died within 5 years of injury. Patients were treated using nonsurgical treatment or surgery, including procedures using the anterior approach, posterior approach, or combined anterior and posterior approaches. Indications for surgery included three-column injury, unstable fracture displacement, neurologic impairment or continuous progress, and intervertebral disc incarceration. By contrast, patients generally received nonsurgical treatment when they had a relatively stable fracture or medical conditions that did not tolerate surgery. Demographic, clinical, and treatment data were collected. The primary study goal was to identify which factors are independently associated with death within 5 years of injury, and the secondary goal was the development of a clinically applicable nomogram. We developed a multivariable Cox hazards regression model, and independent risk factors were defined by backward stepwise selection with the Akaike information criterion. We used these factors to create a nomogram using a multivariate Cox proportional hazards regression analysis. Results After controlling for potentially confounding variables, we found the following factors were independently associated with a lower likelihood of survival after injury: lower fracture site, more-severe peri-injury complications, poorer American Spinal Injury Association (ASIA) Impairment Scale, and treatment methods. We found that a C5 to C7 or T1 fracture (ref: C1 to C4 and 5; hazard ratio 1.7 [95% confidence interval 0.9 to 3.5]; p = 0.12), moderate peri-injury complications (ref: absence of or mild complications; HR 6.0 [95% CI 2.3 to 16.0] ; p 〈 0.001), severe peri-injury complications (ref: absence of or mild complications; HR 30.0 [95% CI 11.5 to 78.3]; p 〈 0.001), ASIA Grade A (ref: ASIA Grade D; HR 2.8 [95% CI 1.1 to 7.0]; p = 0.03), anterior approach (ref: nonsurgical treatment; HR 0.5 [95% CI 0.2 to 1.0] ; p = 0.04), posterior approach (ref: nonsurgical treatment; HR 0.4 [95% CI 0.2 to 0.8]; p = 0.006), and combined anterior and posterior approach (ref: nonsurgical treatment; HR 0.4 [95% CI 0.2 to 0.9] ; p = 0.02) were associated with survival. Based on these factors, a nomogram was developed to predict the survival of patients with ASCF-NI after treatment. Tests revealed that the developed nomogram had good performance (C statistic of 0.91). Conclusion The nomogram developed in this study will allow us to classify patients with different mortality risk levels into groups. This, coupled with the factors we identified, was independently associated with survival, and can be used to guide more appropriate treatment and care strategies for patients with ASCF-NI. Level of Evidence Level III, therapeutic study
    Type of Medium: Online Resource
    ISSN: 0009-921X , 1528-1132
    RVK:
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2023
    detail.hit.zdb_id: 2018318-5
    detail.hit.zdb_id: 80301-7
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  • 2
    In: Optics Express, Optica Publishing Group, Vol. 30, No. 7 ( 2022-03-28), p. 11563-
    Abstract: We report electrically pumped continuous-wave (CW) InAs/GaAs quantum dot lasers directly grown on planar exact silicon (001) with asymmetric waveguide structures. Surface hydrogen-annealing for the GaAs/ Si (001) templates and low-temperature growth for GaInP upper cladding layers were combined in the growth of the laser structure to achieve a high slope efficiency. For the broad-stripe edge-emitting lasers with 2-mm cavity length and 20-µm stripe width made from the above laser structure, a threshold current density of 203.5 A/cm 2 and a single-facet slope efficiency of 0.158 W/A are achieved at ∼1.31 µm band under CW conditions. The extrapolated mean-time-to-failure reaches up to 21000 hours at room temperature, which is deduced from the data measured from C-mount packaged devices. Importantly, these results can provide a practical strategy to realize 1.3 µm wavelength band distributed feedback lasers directly on planar exact Si (001) templates with thin buffer layers.
    Type of Medium: Online Resource
    ISSN: 1094-4087
    Language: English
    Publisher: Optica Publishing Group
    Publication Date: 2022
    detail.hit.zdb_id: 1491859-6
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  • 3
    In: Optics Express, Optica Publishing Group, Vol. 31, No. 3 ( 2023-01-30), p. 4862-
    Abstract: InAs/GaAs quantum dot (QD) laser monolithically grown on silicon is one of the potential approaches to realizing silicon-based light sources. However, the mismatch between GaAs and Si generates a high density of threading dislocations (TDs) and antiphase boundaries (APBs), which trap carriers and adversely affect device performance. In this paper, we present a simple method to reduce the threading dislocation density (TDD) merely through GaAs buffer, eliminating the intricate dislocation filter layers (DFLs) as well as any intermediate buffer layers whose compositions are different from the target GaAs. An APB-free epitaxial 2.5 µm GaAs film was grown on exact Si (001) by metalorganic chemical vapor deposition (MOCVD) with a TDD of 9.4 × 10 6  cm −2 . InAs/GaAs QDs with a density of 5.2 × 10 10  cm −2 were grown on this GaAs/Si (001) virtual substrate by molecular beam epitaxy (MBE) system. The fabricated QD laser has achieved a single facet room temperature continuous-wave output power of 138 mW with a threshold current density of 397 A/cm 2 and a lasing wavelength of 1306 nm. In this work, we propose a simplified method to fabricate high-power QD lasers, which is expected to promote the application of photonic integrated circuits.
    Type of Medium: Online Resource
    ISSN: 1094-4087
    Language: English
    Publisher: Optica Publishing Group
    Publication Date: 2023
    detail.hit.zdb_id: 1491859-6
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  • 4
    In: Optics Express, Optica Publishing Group, Vol. 31, No. 5 ( 2023-02-27), p. 7900-
    Abstract: InGaAs/AlGaAs multiple quantum well lasers grown on silicon (001) by molecular beam epitaxy have been demonstrated. By inserting InAlAs trapping layers into AlGaAs cladding layers, misfit dislocations easily located in the active region can be effectively transferred out of the active region. For comparison, the same laser structure without the InAlAs trapping layers was also grown. All these as-grown materials were fabricated into Fabry-Perot lasers with the same cavity size of 20 × 1000 µm 2 . The laser with trapping layers achieved a 2.7-fold reduction in threshold current density under pulsed operation (5 µs-pulsed width, 1%-duty cycle) compared to the counterpart, and further realized a room-temperature continuous-wave lasing with a threshold current of 537 mA which corresponds to a threshold current density of 2.7 kA/cm 2 . When the injection current reached 1000 mA, the single-facet maximum output power and slope efficiency were 45.3 mW and 0.143 W/A, respectively. This work demonstrates significantly improved performances of InGaAs/AlGaAs quantum well lasers monolithically grown on silicon, providing a feasible solution to optimize the InGaAs quantum well structure.
    Type of Medium: Online Resource
    ISSN: 1094-4087
    Language: English
    Publisher: Optica Publishing Group
    Publication Date: 2023
    detail.hit.zdb_id: 1491859-6
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  • 5
    In: Materials Letters, Elsevier BV, Vol. 166 ( 2016-03), p. 263-266
    Type of Medium: Online Resource
    ISSN: 0167-577X
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2016
    detail.hit.zdb_id: 710033-4
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  • 6
    In: Physica Scripta, IOP Publishing, Vol. 99, No. 8 ( 2024-08-01), p. 085547-
    Abstract: Great advancements in III–V/Si epitaxy have pushed quantum dot lasers to the forefront of silicon photonics. In this work, we designed the structures of evanescent coupled quantum dot distributed feedback lasers with asymmetric gratings, which made significant improvement in on-chip output power while maintaining single-longitudinal-mode stability. The optimal λ /4 phase-shift position (the ratio of the grating length from the rear-end of λ /4 phase-shift to the total grating length) from conventional position of 0.50 to 0.64 allows the ratio of the output power at both sides of silicon waveguide to be increased from 1.0 to 5.9. Moreover, the optimal duty cycle at one side of the phase-shift from 0.50 to 0.8 allows the ratio to be increased from 1.0 to 3.7. Meanwhile, the ratio could be dramatically improved from 1.0 to 9.2 by changed the duty cycle at one side of phase-shift to 0.7 while maintaining the phase-shift position of 0.64. With those designed structures, evanescent coupled quantum dot lasers could challenge the state-of-the-art bonded quantum well lasers and may eventually become ubiquitous and affordable for future commercial production.
    Type of Medium: Online Resource
    ISSN: 0031-8949 , 1402-4896
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2024
    detail.hit.zdb_id: 1477351-X
    detail.hit.zdb_id: 123532-1
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  • 7
    Online Resource
    Online Resource
    Institute of Electrical and Electronics Engineers (IEEE) ; 2023
    In:  IEEE Sensors Journal Vol. 23, No. 10 ( 2023-5-15), p. 10950-10958
    In: IEEE Sensors Journal, Institute of Electrical and Electronics Engineers (IEEE), Vol. 23, No. 10 ( 2023-5-15), p. 10950-10958
    Type of Medium: Online Resource
    ISSN: 1530-437X , 1558-1748 , 2379-9153
    Language: Unknown
    Publisher: Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2023
    detail.hit.zdb_id: 2051518-2
    detail.hit.zdb_id: 2052059-1
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  • 8
    In: Laser Physics Letters, IOP Publishing, Vol. 21, No. 5 ( 2024-05-01), p. 055002-
    Abstract: We report electrically pumped continuous-wave (CW) InAs/GaAs quantum dot lasers monolithically grown on planar on-axis Si (001) substrates. Combining an asymmetric waveguide epitaxy structure with aluminium-free upper cladding layers and a symmetrical cathode chip structure, 1.3 μ m band lasers with low differential resistance and high slope-efficiency have been achieved. Moreover, the optimized symmetrical cathode structure of the laser chips is used to improve the slope-efficiency by reducing the differential resistance and waste heat. The Fabry–Perot broad-stripe edge-emitting lasers with 2000 μ m cavity length and 15 μ m stripe width achieve a single-facet output power of 73 mW, a single-facet slope efficiency of 0.165 W A −1 , and a differential resistance of 1.31 Ω at ∼1.31 μ m wavelength under CW conditions at room temperature (25 °C). Importantly, these results provide an effective strategy to achieve 1.3 μ m wavelength band single-mode distributed feedback lasers directly on planar on-axis Si (001) substrates with high efficiency.
    Type of Medium: Online Resource
    ISSN: 1612-2011 , 1612-202X
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2024
    detail.hit.zdb_id: 2222301-0
    detail.hit.zdb_id: 2131546-2
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  • 9
    In: APL Materials, AIP Publishing, Vol. 11, No. 9 ( 2023-09-01)
    Abstract: The enhancement of the reliability of the silicon-based III–V quantum well lasers, especially of those on an on-axis Si (001) substrate, is of great importance now a days for the development of Si-based photonic and even optoelectronic integrated circuits and is really quite challenging. As an experimental advancement, mainly by inserting a pair of InAlAs strained layers separately into the upper and lower AlGaAs cladding layers to effectively prevent the formation of the in-plane gliding misfit-dislocations within the boundary planes of the active region, the longest room-temperature and continuous-wave lifetime of the InGaAs/AlGaAs quantum well lasers on an on-axis Si (001) substrate with a cavity length of 1500 µm and a ridge width of 20 µm has been prolonged from a very initial record of ∼90 s to the present length longer than 31 min. While, the highest continuous-wave operation temperature of another one with a cavity length of 1000 µm and a ridge width of 10 µm has been shown as 103 °C with an extracted characteristic temperature of 152.7 K, further enhancement of the device reliability is still expected and would mainly depend on the level of the threading-dislocation-density reduction in the GaAs/Si virtual substrate.
    Type of Medium: Online Resource
    ISSN: 2166-532X
    Language: English
    Publisher: AIP Publishing
    Publication Date: 2023
    detail.hit.zdb_id: 2722985-3
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  • 10
    In: Applied Physics Letters, AIP Publishing, Vol. 121, No. 6 ( 2022-08-08)
    Abstract: Room-temperature continuous-wave operation of InGaAs/AlGaAs quantum well lasers directly grown on on-axis silicon (001) has been demonstrated. A 420 nm thick GaAs epilayer completely free of antiphase domains was initially grown on the silicon substrate in a metal-organic chemical vapor deposition system and the other epilayers, including four sets of five-period strained-layer superlattices and the laser-structural layers, were successively grown in a molecular beam epitaxy system. The lasers were prepared as broad-stripe Fabry–Pérot ones with a stripe width of 21.5 μm and a cavity length of 1 mm. Typically, the threshold current and the corresponding threshold current density are 186.4 mA and 867 A/cm2, respectively. The lasing wavelength is around 980 nm, and the slope efficiency is 0.097 W/A with a single-facet output power of 22.5 mW at an injection current of 400 mA. This advancement makes the silicon-based monolithic optoelectronic integration relevant to quantum well lasers more promising with an enhanced feasibility.
    Type of Medium: Online Resource
    ISSN: 0003-6951 , 1077-3118
    RVK:
    Language: English
    Publisher: AIP Publishing
    Publication Date: 2022
    detail.hit.zdb_id: 211245-0
    detail.hit.zdb_id: 1469436-0
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