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Objective: Using finite element analysis to identify the optimal internal fixation method for oblique lateral lumbar interbody fusion (OLIF), providing guidance for clinical practice. Methods: A finite element model of the L4 - L5 segment was created. Five types of internal fixations were simulated in the generated L4-L5 finite element (FE) model. Then, six loading scenarios, i.e., flexion, extension, left-leaning, right-leaning, rotate left, and rotate right, were simulated in the FE models with different types of fixations. The biomechanical stability of the spinal segment after different fixations was investigated. Results: Regarding the range of motion (ROM) of the fused segment, OLIF + Bilateral Pedicle Screws (BPS) has a maximum ROM of 1.82° during backward bending and the smallest ROM in all directions of motion compared with other models. In terms of the von Mises stress distribution on the cage, the average stress on every motion direction of OLIF + BPS is about 17.08MPa, and of OLIF + Unilateral Vertebral Screw - Pedicle Screw (UVS-PS) is about 19.29 MPa. As for the von Mises stress distribution on the internal fixation, OLIF + BPS has the maximum internal fixator stress in left rotation (31.85 MPa) and OLIF + Unilateral Pedicle Screw (UPS) has the maximum internal fixator stress in posterior extension (76.59 MPa). The data of these two models were smaller than those of other models. Conclusion: OLIF + BPS provides the greatest biomechanical stability, OLIF + UPS has adequate biomechanical stability, OLIF + UVS-PS is inferior to OLIF + UPS synthetically, and OLIF + Double row vertical screw (DRVS) and Individual OLIF (IO) do not present significant obvious advantages.
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Semiconductor lasers have developed rapidly with the steady growth of the global laser market. The use of semiconductor laser diodes is currently considered to be the most advanced option for achieving the optimal combination of efficiency, energy consumption, and cost parameters of high-power solid-state and fiber lasers. In this work, an approach for optical mode engineering in planar waveguides is investigated. The approach referred to as Coupled Large Optical Cavity (CLOC) is based on the resonant optical coupling between waveguides and allows the selection of high-order modes. The state-of-art of the CLOC operation is reviewed and discussed. We apply the CLOC concept in our waveguide design strategy. The results in both numerical simulation and experiment show that the CLOC approach can be considered a simple and cost-efficient solution for improving diode laser performance.
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Mechanically flexible optoelectronic devices and systems can enable a much broader range of applications than what their rigid counterparts can do, especially for novel bio-integrated optoelectronic systems, flexible consumer electronics and wearable sensors. Inorganic semiconductor could be a good candidate for the flexible PD when it can keep its high performance under the bending condition. Here, we demonstrate a III-V material-based flexible photodetector operating wavelength from 640 to 1700 nm with the high detectivity of 5.18 × 1011 cmâ§Hz1/2/W and fast response speed @1550 nm by using a simply top-to-down fabrication process. The optoelectrical performances are stable as the PDs are exposed to bending cycles with a radius of 15 mm up to 1000 times. Furthermore, the mechanical failure mode of the PD is also investigated, which suggests that the cracking and delamination failure mode are dominant in bending up and bending down direction, respectively. Such a flexible III-V material-based PD and design with stable and high performance could be a promising strategy for the application of the flexible broad spectrum detection.
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The photonic crystal (PC) has been demonstrated to be very effective in improving the extraction efficiency of light-emitting diodes (LEDs). In this paper, high-brightness AlGaInP-based vertical LEDs (VLEDs) with surface PC (SPCLED) and embedded PC (EPCLED) were successfully fabricated. Compared with normal LED (NLED), photoluminescence intensities of SPCLED and EPCLED have been improved up to 30% and 60%, respectively. And the reflection patterns of SPCLED and EPCLED were periodic bright points array, showing the ability to control light in PC. Electroluminescent measurements show that three kinds of LEDs have similar threshold voltages. Simultaneously, the light output power (LOP) of SPCLED and EPCLED has been improved up to 24% and 11% at 200â mA, respectively, in comparison to NLEDs. But the LOP decays earlier for EPCLED due to the excessive heat production. Furthermore, it is demonstrated that the SPCLED and EPCLED luminous uniformity is better. This kind of high brightness PCLED is promising in improving the properties of all kinds of LEDs, especially mini LEDs and micro LEDs.
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The inflammatory cytokines of IL-1ß and TNF-α participate in the process of intervertebral disc degeneration is focused by the spine surgeons. Inflammatory cytokines represented by IL-1ß and TNF-α act as the key factors in the process of intervertebral disc degeneration resulting in low back pain and radicular symptoms. Annulus fibrosus and nucleus pulposus can secrete TNF-α and IL-1ß under the stimulation of mechanical injury, overstressed, genetic susceptibility and infection. The mechanism of inflammatory cytokines in intervertebral disc degeneration needs further investigation. The emphasis of researches will be on the inflammatory cytokines in the regulation of mechanism in the intervertebral disc degeneration, molecular targeted therapy, cell signaling pathways and the best time of anti-inflammatory therapy providing more evidence in the clinical application.
