STUDY DESIGN:Retrospective case series.OBJECTIVE:To characterize failure rates of cervical cages based on manufacturer and design characteristics using the nationwide database of reported malfunctions.BACKGROUND:The Food and Drug Administration (FDA) aims to ensure the safety and efficacy of cervical interbody implants postimplantation; however, intraoperative malfunctions may be overlooked.MATERIALS AND METHODS:The FDA's Manufacturer and User Facility Device Experience database was queried for reports of cervical cage device malfunctions from 2012 to 2021. Each report was categorized based on the failure type, implant design, and manufacturer. Two market analyses were performed. First, "failure-to-market share indices" were generated by dividing the number of failures per year for each implant material by its yearly US market share in cervical spine fusion. Second, "failure-to-revenue indices" were calculated by dividing the total number of failures per year for each manufacturer by their approximate yearly revenue from spinal implants in the US. Outlier analysis was performed to generate a threshold value above which failure rates were defined as greater than the normal index.RESULTS:In total, 1336 entries were identified, and 1225 met the inclusion criteria. Of these, 354 (28.9%) were cage breakages, 54 (4.4%) were cage migrations, 321 (26.2%) were instrumentation-related failures, 301 (24.6%) were assembly failures, and 195 (15.9%) were screw failures. Poly-ether-ether-ketone implants had higher failure by market share indices for both migration and breakage compared with titanium. Upon manufacturer market analysis, Seaspine, Zimmer-Biomet, K2M, and LDR exceeded the failure threshold.CONCLUSION:The most common cause of implant malfunction was breakage. Poly-ether-ether-ketone cages were more likely to break and migrate compared with titanium ones. Many of these implant failures occurred intraoperatively during instrumentation, which underscores the need for FDA evaluation of these implants and their accompanying instrumentation under the appropriate loading conditions before commercial approval.

Here, we demonstrate the implementation of transparent conductive aluminum-doped zinc oxide (AZO) thin films deposited on glass substrate (AZO/glass) by the atomic layer deposition technique in liquid crystal (LC) spatial light modulator (SLM) devices. Structural, optical, and electrical properties as well as surface free energy reveal the high quality and uniformity of deposited AZO layers. We present two types of structures that highlight the multifunctional role of AZO thin films in SLM configurations: (i) as a transparent conductive layer for assembling regular antiparallel LC cells and (ii) as a transparent conductive layer and alignment layer allowing vertical alignment in LC display devices. A comparison of the electro-optical parameters such as pre-tilt angle, phase modulation, driving voltage, and response time of both devices is presented and discussed. AZO thin films prove superior performance, indicating a growing demand for the next generation indium tin oxide-free technology, including advanced display devices and dynamic flat-panel functionalities. (c) 2024 Optica Publishing Group. All rights, including for text and data mining (TDM), Artificial Intelligence (AI) training, and similar technologies, are reserved.

The integration of highly transparent and highly conductive layers plays a crucial role in the advancement of various next-generation optoelectronic technologies. Here, we demonstrate a comparison of optical, electrical and wettability properties of Aluminum-doped Zinc Oxide (AZO) deposited by Atomic Layer Deposition Technique (ALD) with commercially available Fluorine-doped Tin Oxide (FTO) and Indium- doped Tin Oxide (ITO) Transparent Conductive Oxide (TCO) layers. Their impact on the electro-optical modulation behavior when applied in Liquid Crystal (LC) device assemblies are compared and discussed. The AZO layers performance prove that are fully competitive to the commercial FTO and ITO layers and verify the high demand for the next generation indium tin oxide (ITO)-free technology.

In this paper, we present theoretic modelling of color breaking in a holographic-optical-element based Augmented Reality (AR) display. We first build up a theoretic optical model of the AR display system using scalar diffraction method. The discussions about the design parameters of holographic optical elements (HOE) for Augmented Reality (AR) glasses, focusing on color uniformity as a function of the waveguide thickness are conducted. It can be used to evaluate the color breaking of a displayed white image from user’s point of view. The simulation results show that color breaking occurs due to the limitations of pupil size and image shifting caused by the extended eye-box. Moreover, the thickness of the waveguide also causes uneven color distribution. Our model can also provide a way to analyze the relationship between waveguide thickness and color uniformity. In addition, based on those results, we propose a color correction algorithm by applying a pre-compensation scheme to the R/G/B values of each display pixel. Results show light display colors can be better corrected in the wider region of user’s field of view. It demonstrates the feasibility of compensation of color breaking in a holographic-optical-element based AR display.

Herein we present a comprehensive evaluation of the side-chain azobenzene-containing polymer as photo -alignment command surface for nematic Liquid Crystal (LC) device assembly. Decomposition of birefringence creation dynamics was used to elucidate the relation between the photoinduced illumination intensity, pre-tilt angle and anchoring strength at the LC/photopolymer interface. The electro-optical parameters such as threshold voltage, response time and the phase retardation of assembled LC cell were characterized for actinic intensities up to 100 mW/cm2. In azimuthal plane, controlling the illumination intensity improved the anchoring strength by two orders of magnitude and allows to manipulate the LC director at will. Direct impact of the enhanced zenithal anchoring on LC devices decay time during Fre ' edericksz transition was also demonstrated.

The integration of ITO-free transparent conductive layers remains a big challenge for development of next generation technologies. Here, we demonstrate the feasibility of transparent and conductive Aluminum-doped Zinc Oxide (AZO) thin films to operate simultaneously as electrode and alignment layer in Liquid Crystal (LC) device configuration. Controlling the growth process of AZO thin films by Atomic Layer Deposition (ALD) technique results of predominantly (100) crystallographic oriented AZO with very high transparency and excellent conductivity. The exceptionally low surface free energy of (100) oriented AZO, along with the topological modification following the mechanical rubbing treatment were used to elucidate the mechanism of LC molecules alignment on the surface of AZO film. The uniform vertical orientation of the nematic LC director was confirmed by polarized optical microscopy and pretilt angle measurements. The competitive electro-optical performance in terms of phase modulation, threshold and saturation voltages and contrast ratio of the assembled LC device reveals the great potential of AZO thin films as transparent electrode and alignment layer for future LC display applications with versatile functionality.

STUDY DESIGN:A retrospective case series. OBJECTIVE:This study aims to assess the rates of lumbar interbody cage failures based on their material and manufacturer. SUMMARY OF BACKGROUND DATA:Perioperative lumbar interbody cage malfunctions are underreported events in the spine literature and may result in complications. Although the Food and Drug Administration ensures the safety of these devices under physiological conditions after implantation, these devices may experience nonphysiological conditions during implantation, which may be overlooked. MATERIALS AND METHODS:The MAUDE database was examined for reports of lumbar cage device malfunctions from 2012 to 2021. Each report was categorized based on failure type and implant design. A market analysis was performed by dividing the total number of failures per year for each manufacturer by their approximate yearly revenue from spinal implants in the United States. Outlier analysis was performed to generate a threshold value above which failure rates were defined as greater than the normal index. RESULTS:Overall, 1875 lumbar cage malfunctions were identified. Of these, 1230 (65.6%) were cage breakages, 257 (13.7%) were instrument malfunctions, 177 (9.4%) were cage migrations, 143 (7.6%) were assembly failures, 70 (4.5%) were screw-related failures, and 21 (1.1%) were cage collapses. Of the breakages, 923 (74.9%) occurred during insertion or impaction and 97 entries detailed a medical complication or a retained foreign body. Of the migrations, 155 (88.6%) were identified postoperatively, of which 73 (47.1%) detailed complications and 52 (33.5%) required a revision procedure. Market analysis demonstrated that Medtronic, Zimmer Biomet, Stryker, Seaspine, and K2M exceeded the calculated threshold. CONCLUSIONS:Lumbar cages with polyether ether ketone core material failed more frequently by breakage, whereas titanium surface cages failed more frequently by migration. Failure rates varied depending on the manufacturer. Most cage breakages identified in the present study occurred intraoperatively during implantation. These findings call for a more detailed Food and Drug Administration evaluation of these intraoperative malfunctions before commercial approval. LEVEL OF EVIDENCE:Level 4.

Here we demonstrate the fabrication processes and working parameters of tunable phase retarders based on photo-aligned Liquid Crystal (LCs) cells by combining the photo-pattering and self-assembly processes. The proposed LC devices were assembled by Indium Tin Oxide (ITO) transparent conductive layers deposited on a glass and quartz substrates and spin coated with thin polyamide (PI) layer as photo-alignment material. We study the voltage-transmittance and phase retardation behavior of assembled LC cells and demonstrate polarization sensitive spatial patterns, that open promising features for next generation optical elements as waveplates, lenses, phase retarders, etc.

In this paper, we present a space division technique to multiplex communication channels in a regular step-index multimode fiber using holographic correlator. We consider a multimode fiber with a large diameter of core as highly scattering medium. Thus, the focusing laser spot at different position on the incident plane of the fiber excites different sets of modes, which gives a different speckle pattern at the output of the fiber. Hence, each focusing spot can be considered as a communication channel for data transmission. By combining the volume holographic techniques to form channel multi/demultiplexer in a transmission system, we demonstrate conceptually transmission of multichannel optical information by using a regular step-index multimode fiber for data transmission application.

In this work, highly conductive Al-doped ZnO (AZO) films are deposited on transparent and flexible muscovite mica substrates by using the atomic layer deposition (ALD) technique. AZO-mica structures possess high optical transmittance at visible and near-infrared spectral range and retain low electric resistivity, even after continuous bending of up to 800 cycles. Structure performances after bending tests have been supported by atomic force microscopy (AFM) analysis. Based on performed optical and electrical characterizations AZO films on mica are implemented as transparent conductive electrodes in flexible polymer dispersed liquid crystal (PDLC) devices. The measured electro-optical characteristics and response time of the proposed devices reveal the higher potential of AZO-mica for future ITO-free flexible optoelectronic applications.

The integration of high uniformity, conformal and compact transparent conductive layers into next generation indium tin oxide (ITO)-free optoelectronics, including wearable and bendable structures, is a huge challenge. In this study, we demonstrate the transparent and conductive functionality of aluminum-doped zinc oxide (AZO) thin films deposited on glass as well as on polyethylene terephthalate (PET) flexible substrates by using an atomic layer deposition (ALD) technique. AZO thin films possess high optical transmittance at visible and near-infrared spectral range and electrical properties competitive to commercial ITO layers. AZO layers deposited on flexible PET substrates demonstrate stable sheet resistance over 1000 bending cycles. Based on the performed optical and electrical characterizations, several applications of ALD AZO as transparent conductive layers are shown—AZO/glass-supported liquid crystal (LC) display and AZO/PET-based flexible polymer-dispersed liquid crystal (PDLC) devices.

Multilayer graphene, grown by CVD method and transferred on polyethylene terephthalate (PET) substrates has been used as transparent conductive layer for flexible light shutters. Sheet resistance stability during bending of large area graphene is studied. Graphene/PET retains its low sheet resistance, even after continuous bending of up to 1000 times.

John T Sheridan1,∗, Raymond K Kostuk2, Antonio Fimia Gil3, Y Wang4, W Lu4, H Zhong4, Y Tomita5, C Neipp6, J Francés6, S Gallego6, I Pascual6, V Marinova7,8, S-H Lin7, K-Y Hsu7, F Bruder9, S Hansen9, C Manecke9, R Meisenheimer9, C Rewitz9, T Rölle9, S Odinokov10, O Matoba11, M Kumar11, X Quan11, Y Awatsuji12, P W Wachulak13, A V Gorelaya14, A A Sevryugin14, E V Shalymov14, V Yu Venediktov14,15, R Chmelik16, M A Ferrara17, G Coppola17, A Márquez6, A Beléndez6, W Yang18, R Yuste19,20, A Bianco20, A Zanutta20, C Falldorf21, J J Healy1, X Fan22, B M Hennelly22, I Zhurminsky23, M Schnieper23, R Ferrini23, S Fricke23, G Situ24,25, H Wang24,25, A S Abdurashitov26,27, V V Tuchin26,28,29,30, N V Petrov29, T Nomura31, D R Morim32 and K Saravanamuttu32

In this work, high performance conformal Al-doped ZnO (AZO) films are deposited on transparent and flexible muscovite mica substrates by using Atomic Layer Deposition (ALD) technique. AZO/mica films possess high optical transmittance at visible and near-infrared spectral range and retains low electric resistivity, even after continuous bending of up to 800 cycles, confirmed by AFM analysis before and after bending tests. Based on the performed optical and electrical characterizations AZO films are implemented as transparent conductive electrodes in flexible Polymer Dispersed Liquid Crystal (PDLC) smart devices

Graphene has attracted considerable interest as a prospective material for future electronics and opto-electronics. Here, the synthesis process of large area few layers graphene by Atmospheric Pressure Chemical Vapor Deposition (APCVD) technique is demonstrated. Quality assessments of graphene are performed and confirmed by Raman analysis and optical spectroscopy. Next, graphene was transferred on Polyethylene Terephthalate (PET) substrates and implemented as transparent conductive electrode in flexible Polymer Dispersed Liquid Crystal (PDLC) devices. Their electro-optical properties, such as voltage-dependent transmittance and flexibility behavior are measured and discussed. The stability of the sheet resistance after 1200 bending tests of graphene/PET structure is demonstrated. The obtained results open a great potential of graphene integration into the next generation Indium Tin Oxide (ITO) free flexible and stretchable optoelectronics.

Radial polarization converters can convert an incident light into a radially polarized light, which is beneficial in a variety of applications. In this paper, a new design of holographic radial polarization converter is proposed which consists of eight space-variant polarization-selective volume hologram gratings. According to the coupled wave theory, a feasible design of the polarization-selective volume hologram gratings was described. The prism-hologram-prism sandwiched recording method was adopted for the recording. The s- and p-polarization diffraction efficiencies of the fabricated polarization-selective volume hologram gratings at 443.29 nm are 90.83% and 22.09%, respectively. The operation bandwidth is about 4.42 nm. A prototype of holographic radial polarization converter was successfully assembled and tested. Due to the introduction of volume hologram gratings, this design should have the advantages of high diffraction efficiency, narrow band, compactness, and planar configuration, meaning it is especially suitable for low-cost mass production and has high application potential in related fields.

The era of flexible optoelectronics demands development of wearable and bendable structures, foldable touch screens, paper-like displays, and curved and flexible solid-state lighting devices. Here, we demonstrate the fabrication of highly flexible light valves using polymer-dispersed liquid crystal (PDLC) and TiO2/Ag/TiO2 transparent conductive films. TiO2/Ag/TiO2 multilayers were prepared by magnetron sputtering technique on polyethylene terephthalate (PET) substrates at room temperature. By keeping the equivalent TiO2 layers and varying the deposition time of the Ag layer, proper metal nanograins on TiO2 planar plane were formed, providing the best tradeoff between the transmittance, sheet resistance and bending ability. The results are validated by numerical simulations that suggest the best match between the deposition time and individual layer thickness. Based on the performed characteristics of TiO2/Ag/TiO2/PET structures, several flexible light valves are fabricated and characterized. The sheet resistance values of TiO2/Ag/TiO2/PET remain unchanged over 1000 bending cycles. The measured driving voltage and response time values open great potential of TiO2/Ag/TiO2/PET for integration into next-generation ITO-free flexible and stretchable devices.

Mechanical weeding is a necessary means to produce organic soybean in vast area and is the most effective for seedling of weed. However, the growth of weed is inconsistent; we must rely on the quantity of closely weeding to achieve the expected results. Organic cultivation adopts strip planting to reduce the cost of weeding, and uses the cultivator to remove weeds. This operation is slow and with high cost, and the artificial weeding is necessary in the later stage. In contrast, the field weeding robot can provide mechanical or physical prevention of weeds via monitor and image analysis. Therefore, this study aims to effectively increase production and solve the problems of labor shortage and high cost on labors by combining an unmanned ground vehicle with a developing smart laser weeding system for autonomous precise weeding. An intelligent image recognition is adopted to identify the position of the weed, and then through the laser tissue fibrosis to achieve the goal of precise weeding.

In this paper, a near infrared operating spatial light modulator is demonstrated, assembled in a way to combine the excellent photoconductivity of Ru-doped Bi12SiO20 (BSO:Ru) crystal, strong birefringence of liquid crystal (LC) and exceptionally high transparency and conductivity of graphene. A photo-alignment method instead of mechanical rubbing is used to simplify the fabrication procedure and to prevent detachment of the graphene layer from the substrate. The proposed device operates at low driving voltage (competitive to a reference device using ITO electrodes) moreover requires much less near infrared intensity for the light modulation. It is assumed the effect is due to the photo-induced space charge exchange between BSO:Ru and graphene allowing charge redistribution and optical doping effect resulting in a modulation of graphene's properties. The voltage-dependent transmittance and phase retardation show high contrast ratio with the response time of similar to 100 ms at 1064 nm. In addition, by projecting a video image through the proposed structure the response of modulated pump light intensity is demonstrated which supports device ability to work as near infrared optically addressed spatial light modulator (OASLM). The obtained performances reveal great potentials of graphene-based electro-optic devices for near infrared applications.

Aluminum-doped zinc oxide (AZO) layers are prepared by using atomic layer deposition technique. The obtained layers possess high optical transmittance at visible and near-infrared spectral range. By varying the Al content, optimal growth compositions of AZO are established where the electrical conductivity of the film is highest. Based on performed optical and electrical characteristics measurements, selected AZO films with optimal conductivity are implemented as transparent electrodes in liquid crystal display devices. The electro-optical modulation characteristics of these devices are found to be comparable to those of devices using commercial ITO electrodes.