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PurposeThis study aimed to investigate the rate at which patients returned to sports after open wedge high tibial osteotomy and identify the continuity of sports activity post-operatively.MethodsThirty-five patients (40 knees) who underwent open-wedge high tibial osteotomy (OW-HTO) in medial knee osteoarthritis were included in this study. The mean age of the patients who underwent surgery was 55.1 ± 10.7 years, and the mean follow-up period was 41.0 ± 24.7 months. Clinical results and radiographic parameters calculated in standing whole-leg radiographs preoperatively, post-operatively, and at the final follow-up were evaluated.ResultsThirty-one patients (88.6%) were able to return to preoperative sports activity; however, only 14 patients (40.0%) completely returned to preoperative sports activity levels. Of the 31 patients who returned to sports activity, 10 patients (32.3%) maintained post-operative sporting activity levels at the final follow-up. In radiographic parameters, the weight-bearing line ratio was considered loss of correction in the post-operative period leading to the final follow-up. Patients who completely returned to sports and maintained sporting activity levels at the final follow-up had significantly higher the Knee Injury and Osteoarthritis Outcome Score pain subscale values and lower visual analogue scale of knee pain at pre-surgery and final follow-up than other patients, including those who partially returned to sports.ConclusionsThe proportion of patients who returned to sports after OW-HTO and were able to participate in competitions at the same activity level as before surgery was low and insufficient.Level of evidenceRetrospective case series, IV

The 2019 novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has caused a global outbreak of infection. In general, children with coronavirus disease-2019 have been reported to show milder respiratory symptoms than adult patients. Here, we have described a case of a SARS-CoV-2-infected infant who presented to our hospital with a severe episode of an apparent life-threatening event (ALTE). An 8-month-old, otherwise healthy female infant presented to our hospital because of a sudden cardiopulmonary arrest. Approximately 1 h before this episode, the patient showed no symptoms, except a worse humor than usual. On arrival at our hospital, the patient had severe acidosis, but there were no clear signs of inflammatory response. Chest computed tomography showed weak consolidations in the upper right lung and atelectasis in the lower left lung. No signs of congenital heart disease or cardiomyopathy were observed on echocardiography, and no significant arrhythmia was observed during the clinical course. However, SARS-CoV-2 RNA was detected by real-time reverse transcription polymerase chain reaction in tracheal aspirate and urine samples. Although the assessment of further similar cases is indispensable, this case suggests that SARS-CoV-2 infection may be an underlying factor in the pathophysiology of ALTE.

The overall prognosis of patients with sarcoma-based cancers has changed little in the last 20 years. There is an urgent need to investigate the metastatic potential of these tumors and to develop anti-metastatic drugs. It is becoming increasingly clear that platelets play an important role in the establishment of metastasis of carcinoma cells and could be a useful therapeutic target for patients with carcinoma. However, little is known about the role of platelets in sarcoma progression. Here, we investigated how osteosarcoma progression relates to platelet function to explore the possibility of anti-platelet therapy. We found that, similar to carcinoma cells, podoplanin (also known as Aggrus)-positive osteosarcoma cells induce platelet aggregation and activation. Administration of anti-glycoprotein Ibα (GPIbα, also known as CD42b) antibody reduced the lung metastasis of osteosarcoma. The supernatant from platelets cocultured with osteosarcoma cells contained several growth factors and promoted proliferation, invasiveness, and sphere formation of osteosarcoma cells in vitro. In addition, the development of lung metastasis was highly dependent on direct interaction between osteosarcoma cells and platelets. To explore the therapeutic target, we focused on the interactions between podoplanin on osteosarcoma and C-type lectin-like receptor (CLEC)-2 on platelets. The administration of a depleting antibody against CLEC-2 efficiently suppressed osteosarcoma metastasis into the lung. We also analyzed clinical data from patient samples at primary and metastatic sites. Although GPIbα expression was similar between the two sites, there was a significant increase in podoplanin at the metastatic site compared to that in the primary site, and the level of podoplanin expression in the primary site correlated with patient prognosis. These findings suggest that blockade of interactions between platelets CLEC-2 and osteosarcoma podoplanin represent the most promising therapeutic strategy for preventing the lung metastasis of osteosarcoma. © 2020 American Society for Bone and Mineral Research.

Highlights • Novel coronavirus (SARS-Coronavirus-2:SARS-CoV-2) which emerged in Wuhan, China, has spread to multiple countries rapidly. • This is the first case of meningitis associated with SARS-CoV-2 who was brought in by ambulance. • The specific SARS-CoV-2 RNA was not detected in the nasopharyngeal swab but was detected in a CSF. • This case warns the physicians of patients who have CNS symptoms., Novel coronavirus (SARS-Coronavirus-2:SARS-CoV-2) which emerged in Wuhan, China, has spread to multiple countries rapidly. We report the first case of meningitis associated with SARS-CoV-2 who was brought in by ambulance due to a convulsion accompanied by unconsciousness. He had never been to any foreign countries. He felt generalized fatigue and fever (day 1). He saw doctors nearby twice (day 2 and 5) and was prescribed Laninamivir and antipyretic agents, His family visited his home and found that he was unconsciousness and lying on the floor in his vomit. He was immediately transported to this hospital by ambulance (day 9). Under emergency transport, he had transient generalized seizures that lasted about a minute. He had obvious neck stiffness. The specific SARS-CoV-2 RNA was not detected in the nasopharyngeal swab but was detected in a CSF. Anti- HSV 1 and varicella-zoster IgM antibodies were not detected in serum samples. A brain MRI showed hyperintensity along the wall of right lateral ventricle and hyperintense signal changes in the right mesial temporal lobe and hippocampus, suggesting the possibility of SARS-CoV-2 meningitis. This case warns the physicians of patients who have CNS symptoms.

In this paper, geometric-phase lenses, which can not only correct wavefront aberrations but also magnify an aerial image, have been proposed for use in an aerial display system composed of a retroreflector array, an orthogonal-circular polarization grating, a right-angle prism, and a quarter-wave plate. The geometric-phase lenses were demonstrated both experimentally and computationally by arranging them in the aerial display configuration and observing aerial images. We also investigated the relationship between the magnification and the field of view of an aerial image, and it has been found that there is the trade-off relationship between them.

The incident angle dependence of the diffraction properties of orthogonal-circular polarization gratings (OCPGs) fabricated using a polymer liquid crystal exhibiting biaxial anisotropy have been investigated. It was found that a specific biaxial anisotropy reduces the incident angle dependence of optically thin OCPGs against the wavelength of an incident light.

Background: To preserve the ability to perform physical activities among the elderly, the concept of locomotive syndrome and its evaluation method, the locomotive syndrome risk test, have been applied in an integrated manner to capture the decline in mobility resulting from musculoskeletal disorders. During treatment, physicians can use the locomotive syndrome risk test to evaluate the impact of each therapy such as total knee arthroplasty for knee osteoarthritis, a common disorder found in locomotive syndrome. The purpose of this study was to evaluate the impact of total knee arthroplasty in the elderly with respect to locomotive syndrome.Methods: A total of 111 patients were registered at six hospitals prior to total knee arthroplasty and postoperatively followed up for 1 year. Three components of the locomotive syndrome risk test (the two-step test, stand-up test, and geriatric locomotive function scale-25) were assessed together with the EuroQol-5 Dimension scores pre- and postoperatively.Results: Post surgery, all three components of the locomotive syndrome risk test as well as the EuroQol-5 Dimension utility score showed significant improvements from the baseline (two-step test, 1.01±0.25 to 1.12±0.21; stand-up test, 2.02±1.14 to 2.38±1.20; geriatric locomotive function scale-25, 38.3±15.8 to 18.7±16.6, mean ± standard deviation). The ratio of stage 3 locomotive syndrome patients (progressed stage of decrease in mobility, restricting social engagement) reduced from 82.3% to 33.9% postoperatively. There was no significant difference in the degree of change in the three test scores between the younger (60-74 years) and older (≥75 years) age groups. Conclusions: We found that total knee arthroplasty has a major impact in preventing the progression of locomotive syndrome in patients with knee osteoarthritis. The locomotive syndrome risk test is a feasible tool for longitudinal evaluation of patients with musculoskeletal diseases of varying severity and with multiple symptoms.Trial registration: This study was registered as UMIN000023595 (10/08/2016)

Coronavirus disease 2019 is diagnosed based on the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA in nasopharyngeal swabs or saliva samples using reverse-transcription quantitative polymerase chain reaction. Nasopharyngeal swabs should be collected by medical professionals who are covered with full personal protective equipment (PPE), while saliva samples can be collected by patients themselves without any PPE. However, collecting saliva is difficult for people who are unable to follow instructions, including infants or unconscious patients. Owing to the high viscosity of saliva, special attention is required to handle saliva samples in laboratories. To solve these problems, we compared lingual and buccal mucosal swabs (oral swabs) with nasopharyngeal swabs and saliva samples. Among 13 patients who had a positive result for SARS-CoV-2 RNA in their nasopharyngeal swabs, 8 and 10 patients had a positive result for SARS-CoV-2 RNA in their saliva (concordance rate, 61.5%) and oral swabs (76.9%), respectively. Among the eight patients with a positive result for SARS-CoV-2 RNA in saliva, seven (87.5%) had SARS-CoV-2 detected in their oral swabs. We could not obtain saliva samples from four patients, but we found perfect concordance of SARS-CoV-2 positivity between the nasopharyngeal and oral swabs. Therefore, oral swabs can be used for SARS-CoV-2 RNA detection.

Purpose: To elucidate the association between medial meniscus extrusion measured on ultrasonography (MMEUS) and the prevalence of medial meniscus posterior root tear detected on magnetic resonance imaging (MMPRTMRI). Methods: We recruited 127 patients (135 knees) in this cross-sectional study. All participants had medial knee pain without a knee trauma or surgery history. Knee osteoarthritis (KOA) severity was evaluated using Kellgren-Lawrence grade (KLG) scores. Patients with KLG scores 0-1 and ≥2 were classified in non-radiographic (non-ROA) and radiographic KOA (ROA) groups, respectively. MMEUS was measured with patients in the supine position. Based on T2*-weighted images, MMPRTMRI was defined as the presence of “Ghost meniscus sign” and “Creft/truncation sign”, indicating an abnormal high signal intensity of a disrupted posterior root. MMEUS was compared between MMPRT+ and MMPRT– patients using a non-paired t-test. Receiver operating characteristic (ROC) curves were used to determine the optimal cut-off MMEUS to predict MMPRT+.Results: The prevalence of MMPRT+ was 31.3% (25/80 knees) and 29.1% (16/55 knees) in the non-ROA and ROA groups. The MMEUS of MMPRT+ patients were significantly greater than that of MMPRT– patients in both the non-ROA (5.9±1.4 mm vs. 4.4±1.0 mm, PUS were the optimal cut-off values in non-ROA (adjusted odds ratio: 6.280; area under the curve [AUC]: 0.809; PConclusions: In early non-radiographic KOA stages, a greater MMEUS was associated with a higher MMPRTMRI prevalence.Level of evidence: III, Cross-sectional cohort study

A polarized laser beam steering system using multiply cascaded rotating polarization gratings (PGs) is presented. The rotating PGs steer incident circularly polarized beams with high optical throughput because the theoretical limitation of the PG diffraction efficiency is 100%. The system also offers more rapid rotation when compared with wedge prism pairs because of the weight of the PGs. The beam steering performance was analyzed theoretically for schemes using two and four rotating PGs. The system’s feasibility was demonstrated experimentally by projecting Lissajous and raster patterns using PGs fabricated from photocrosslinkable polymer liquid crystal films via a photo-alignment technique. The steered beam’s diffraction efficiency and ellipticity were maintained at 83 ∼ 89 % and 96 ∼ 99 % , respectively, during PG rotation. This beam steering system will be applicable to light detection and ranging, optical imaging, and laser displays.

In recent years, vector beam (VB)-based optical multiplexing communication is attracting attention to increase the information transfer capacity, and hence several types of VB demultiplexers fabricated by using liquid crystals have been reported. In this presentation, we propose a crossed-fork-shaped polarization grating (CFPG) as a new VB demultiplexer. The CFPG was fabricated by recording multiple polarization holograms onto the photocrosslinkable polymer liquid crystal. Recorded each polarization hologram works individually to act as a VB detector, which converts specific VB into a Gaussian beam with diffraction. The CFPG has the potential to miniaturize the demultiplexer because several VB detection functions can be integrated. VB detection between radial and azimuthal polarizations also demonstrated by using a pair of quarter-wave PG and normal-FPG.

We have succeeded in forming a polarization grating whose polarization diffraction properties are extremely independent of the incident angle by using polymer liquid crystal exhibiting biaxial optical anisotropy. It is considered that the extension of the optical path length and the decrease in the effective amplitude of optical anisotropy due to oblique incidences are offset by the biaxial optical anisotropy and, as a result, the retardation is compensated. The properties of this developed device have been experimentally demonstrated and theoretically explained.

We report a terahertz (THz) metamaterial consisting of a metal mesh layer with nematic liquid crystals (LCs). The metal mesh has subwavelength apertures that function as a bandpass filter in the THz spectral range. The LCs are embedded and aligned homogeneously in the apertures. The electromagnetic characteristics were calculated with a finite-difference time-domain method. The metamaterial converts the polarization of the THz wave during transmission and the thickness of the LC layer can be reduced by two orders of magnitude relative to the homogeneously aligned LC without the meta-structures. This increases the response speed to applied external fields. We also fabricated the metamaterial using a dielectric substrate with a metal mesh layer, a nematic LC, and a dielectric substrate with a polymeric alignment layer and investigated its polarization conversion using THz time-domain spectroscopy. The experimental results demonstrated that metal mesh structures with LCs are useful for active THz polarization converters.

We report the propagation properties of polarized terahertz (THz) waves in a liquid crystal (LC) cell with subwavelength metallic gratings to produce transmissive THz elements with electrical tunability. One-dimensional metallic gratings, which can be used both as transparent electrodes and linear polarizers in the THz regime, were fabricated on the quartz glass substrates of the LC cell. The substrates with and without the metallic grating showed almost identical transmission spectra for a linearly polarized THz wave whose electric field was parallel to the grating vector. We fabricated a 90 ∘ -twisted nematic LC cell using the two substrates with the metallic grating and examined its transmission spectra in the THz regime. During these measurements, we applied a voltage to the LC via the metallic gratings. We calculated in detail the transmission spectra and its voltage dependence based on the effective medium theory for subwavelength structures, the continuum theory of twisted nematic LCs, and the optical constants of the LC in the THz regime. The observed spectra agreed well with theoretical simulations. These results demonstrate that LC cells with subwavelength metallic gratings are useful as active THz elements in applications such as attenuators and polarization rotators.

Platelets participate in not only thrombosis and hemostasis but also other pathophysiological processes, including tumor metastasis and inflammation. However, the putative role of platelets in the development of solid organs has not yet been described. Here, we report that platelets regulate lung development through the interaction between the platelet-activation receptor, C-type lectin-like receptor-2 (Clec-2; encoded by Clec1b), and its ligand, podoplanin, a membrane protein. Clec-2 deletion in mouse platelets led to lung malformation, which caused respiratory failure and neonatal lethality. In these embryos, α-smooth muscle actin-positive alveolar duct myofibroblasts (adMYFs) were almost absent in the primary alveolar septa, which resulted in loss of alveolar elastic fibers and lung malformation. Our data suggest that the lack of adMYFs is caused by abnormal differentiation of lung mesothelial cells (luMCs), the major progenitor of adMYFs. In the developing lung, podoplanin expression is detected in alveolar epithelial cells (AECs), luMCs, and lymphatic endothelial cells (LECs). LEC-specific podoplanin knockout mice showed neonatal lethality and Clec1b-/--like lung developmental abnormalities. Notably, these Clec1b-/--like lung abnormalities were also observed after thrombocytopenia or transforming growth factor-β depletion in fetuses. We propose that the interaction between Clec-2 on platelets and podoplanin on LECs stimulates adMYF differentiation of luMCs through transforming growth factor-β signaling, thus regulating normal lung development.

The incident angle dependences of the diffraction properties of orthogonal-circular polarization gratings (OCPGs) fabricated using a polymer liquid crystal exhibiting biaxial anisotropy have been investigated. The investigations were conducted with the plane orthogonal to the surface of the OCPGs as the plane of incidence. It was found that a specific biaxial anisotropy reduces the incident angle dependence of optically thin OCPGs against the wavelength of the incident light, and is less effective on thick OCPGs. In addition, a method also has been proposed to determine the biaxial anisotropic shape that most reduces the incident angle dependence in thin OCPGs.

We developed a method for the design of multilevel anisotropic diffraction gratings based on a genetic algorithm. The method is used to design the multilevel anisotropic diffraction gratings based on input data that represent the output from the required grating. The validity of the proposed method was evaluated by designing a multilevel anisotropic diffraction grating using the outputs from an orthogonal circular polarization grating. The design results corresponded to the orthogonal circular polarization grating structures that were used to provide outputs to act as the input data for the process. Comparison with existing design methods shows that the proposed method can reduce the number of human processes that are required to design multilevel anisotropic diffraction gratings. Additionally, the method will be able to design complex structures without any requirement for subsequent examination by a human designer. The method can contribute to the development of optical elements by designing multilevel anisotropic diffraction gratings.

A crossed-fork shaped polarization grating (Crossed-FPG) was developed as a mode demultiplexer for vector beam division multiplexing communication. The Crossed-FPG was fabricated by recording several polarization holograms between optical vortex and Gaussian beam with opposite-handed circular polarizations. Mode detection of vector beams was experimentally demonstrated.

A quaternary liquid crystal (LC) grating simultaneously performs dynamic control of diffraction angle, polarization, and wavelength-separation properties as shown in the following: (1) Diffraction orders in which light waves are diffracted can be selected by applying a voltage, (2) the efficiency of each diffraction order can be controlled depending on a wavelength of an incident beam, and (3) a pair of counter-rotated circular polarizations or linear polarizations with an orthogonal relationship are diffracted simultaneously, and this property can be controlled by applying a voltage. These diffraction properties and LC alignment structures are proposed based on theoretical analyses using Jones calculus, and their properties are now demonstrated experimentally. The quaternary LC grating can be used as an advanced optical element for industrial applications such as tunable polarization beam splitters and dynamic switching of propagation directions of light depending on wavelength.

We proposed Nonlinear Map Optimization (NMO) to improve the solution search capability of particle swarm optimization (PSO) algorithm. NMO is one of PSO-based swarm intelligence algorithms. We have previously proposed a canonical deterministic system PSO (CD-PSO) that is removed probabilistic factors from PSO to analyze its solution search behavior and is extracted only the essential dynamics of the solution search property of PSO. Although the dynamics of CD-PSO describe the basic dynamics of PSO, the solution search performance of CD-PSO is very poor than PSO. One of the causes is the distribution of search points. Although the search point distribution of PSO has a normal distribution shape depending on stochastic factors, the search point distribution of CD-PSO which is a deterministic system is not similar to the normal distribution. In order to improve the search point distribution of CD-PSO, we proposed a modified CD-PSO. Based on the modified CD-PSO, we proposed an NMO algorithm whose search points are derived by a nonlinear map. In this article, we clarify that the solution search property of NMO. The distribution of search points is similar to a normal distribution shape. Also, the nonlinear mapping of NMO derives complex behavior due to nonlinearity depended on parameters. These properties lead to the local search capability of NMO which is improved compared to PSO. Also, information exchange within the swarm similar to PSO is related to the global search ability. Since NMO can consider local search and global search separately, the solution search capability can be improved with unimodal functions than conventional PSO.

The diffraction properties of liquid crystal (LC) cells fabricated by photoalignment substrates with different periodic optical anisotropic distributions are demonstrated. The twist angle distribution structure inside the LC cells formed by the grating period difference between photoalignment substrates is called "beat structure." In addition to diffraction corresponding to the grating periods of photoalignment substrates, beat structure itself also functions as a diffraction grating. The diffraction properties can be controlled by varying the retardation. The fabrication method and diffraction properties of the LC cells with beat structure are explained by both experiment and theoretical analysis.

A hybrid polarization grating that can spatially separate orthogonal states of a vector beam with the same polarization topological charge is presented. The hybrid polarization grating is assembled using a fork-shaped polarization grating and a quarter-wave polarization grating and acts as a common pass interferometer for right- and left-circular polarization components of incident vector beams. The hybrid polarization grating can separate two vector beam states that have a 90 ° relative polarization azimuth angle difference. The number of detectable vector beams can be increased by replacing the hybrid polarization grating with a crossed-hybrid polarization grating. Device feasibility was demonstrated experimentally using hybrid polarization grating and crossed-hybrid polarization grating fabricated using the photoalignment method for photoreactive liquid crystals. This approach has the potential to demultiplex several vector beams stably and simultaneously using a compact optical system and should be applicable to vector beam division multiplexing and other applications requiring vector beam detection.

We propose two types of wavefront aberration correction in geometric-phase lenses (GPLs). First, in situations in which the incident light on a GPL has a wavefront aberration represented by the Zernike polynomial, the wavefront aberration is eliminated by setting a phase distribution that cancels the phase distribution of the incident light to GPL. Second, the aberration that occurs when a light wave is obliquely incident on the GPL is compensated for by a correction method that incorporates an optimization design using a genetic algorithm. These methods have been demonstrated not only by theory but also by experiments using imaging systems in which the designed and fabricated GPLs are utilized. These wavefront aberration correction methods can be expected to overcome wavefront aberration caused by the arrangement of optical elements in an optical system and contribute to expanding the application range of GPLs.

An aerial display scheme consisting of an orthogonal circular polarization grating (OCPG), a waveplate, a retroreflector array (RRA), and a right-angle prism (RAP) was developed. Because of the OCPG’s functionality, retroreflected light from the RRA is transmitted through the RAP boundary surface by avoiding the total reflection condition. The proposed system can potentially increase optical throughput to 100% by designing the boundary surface incidence angle to be Brewster’s angle. The scheme’s feasibility was demonstrated experimentally using an OCPG and waveplate that were fabricated from polymer liquid crystal with optical anisotropy using a photoalignment technique. The scheme should be used as a type of aerial display that is compatible with polarization-diffractive elements called Pancharatnam–Berry phase elements.

A novel, to the best of our knowledge, method for circular-polarization imaging with white light is presented. The vital optical elements of the proposed system are two polarization gratings (PGs) and a wedge prism. The chromatic dispersion of the PG diffraction angle is compensated by the difference of the grating period for the two PGs. In addition, the distance between the diffracted lights on the imaging plane is controlled by using a wedge prism. As a result, S 3 of the Stokes parameter, including the wavelength dependence of a scarab beetle, was observed at a time, and the S 3 contribution to each color was determined by using the color filter of the light-receiving element. Because the white-light polarization image includes a lot of information about the illuminated structure, the proposed method should be applied to biomedical sensing and remote sensing.

We developed a three-terminal spintronic memristor named spin-memristor for the artificial synapse of neuromorphic devices. Current-induced domain wall (DW) motion type magnetoresistance was used to generate variable analog conductance changes. Magnetic tunnel junction with a perpendicularly magnetized DW layer was fabricated on a silicon substrate. Due to the forward and backward DW motions, a linear and symmetric conductance response was achieved. The impact of memristive behavior on neural networks was evaluated using numerical simulation of hand-written digit recognition. This spin-memristor is identified as one of the promising candidates for artificial synapses in analog neuromorphic devices.

We present a simple yet versatile and practical polarization camera for imaging full Stokes parameters. The developed system consists of one anisotropic diffraction grating plate and two electro-switchable retarders and obtains in nearly real-time full Stokes images of the light scattered from the objects. The monochromatic S3 image is obtained by physically separating the right and left circularly polarized components with the aid of the anisotropic grating, and S1 and S2 images are obtained by fast electro-switching the retardation of each retarder. The simple polarization imaging system has possible applications in various types of imaging systems and especially should be incorporated into optical microscopes as well as imaging cameras in future work.

We report herein our investigation of planar terahertz (THz) metamaterials with metallic fish-scale structure. The fish-scale metamaterials with different slant angles were designed based on finite-difference time-domain simulations and fabricated on a dielectric substrate by using a laser-beam drawing system. Theoretical simulations indicate that the eigenpolarization states of the slant fish-scale metamaterials are corotating elliptical polarizations with orthogonal azimuth angles (i.e., the slant fish-scale metamaterials possess planar chirality in the THz spectral range). We measured the transmission spectra and polarization-conversion property of the fabricated metamaterials by using THz time-domain spectroscopy with a wire-grid polarizer. The results were consistent with the theoretical simulations. The experimental and calculation data clarify that both the azimuth angle and elliptical angle of the polarized THz wave transmitted through the planar metamaterial can be controlled by the slant angle of the fish-scale pattern. This study demonstrates the potential of the fish-scale metamaterials for polarization converters in the THz spectral range.

Polarization holographic gratings were formed in liquid crystal (LC) cells fabricated from a mixture of low molecular weight nematic LC and a photoreactive liquid crystalline polymer (PLCP) with 4-(4-methoxycinnamoyloxy)biphenyl side groups. The diffraction properties of the gratings were analyzed using theoretical models which were determined based on the polarization patterns of the polarization holography. The results demonstrated that vector gratings comprised of periodic orientation distributions of the LC molecule were induced in the cells based on the axis-selective photoreaction of the PLCP. The vector gratings were erased by applying a sufficiently high voltage to the cells and then were reformed with no hysteresis after the voltage was removed. This phenomenon suggested that the PLCP molecules were stabilized based on the axis-selective photocrosslink reaction and that the LC molecules were aligned by the photocrosslinked PLCP. This LC composite with axis-selective photoreactivity is useful for various optical applications, because of their stability, transparency, and response to applied voltage.

Enhancement of optical transmittance of polymer-dispersed liquid crystal (PDLC) cells was investigated by introducing a modification into the substrates. Surface treatment by rubbing was performed on both network-type and droplet-type PDLCs to investigate the effect on the optical transmittance of the cells. Differences in the transmittance of the PDLC in the polymer matrix were observed by introducing rubbing effect on network-type PDLC but not on droplet-type PDLC. These phenomena might be used to distinguish the application field of both types of PDLC cells by enhancing optical transmittance and scattering properties.

To fabricate fine metal structure, we proposed and demonstrated a method by using interference pattern of copropagating optical vortices and lift-off process. This method can fabricate more fine structure compared with the conventional laser drawing method using Gaussian beam even if the low numerical aperture condition.

[Purpose] The purpose of this study was to investigate whether transcutaneous electrical nerve stimulation simultaneously combined with local heat and cold applications enhances pain relief compared with transcutaneous electrical nerve stimulation alone in patients with knee osteoarthritis. [Subjects and Methods] Fourty-five patients with knee osteoarthritis participated in this study. They were randomly assigned to the following three interventions: transcutaneous electrical nerve stimulation simultaneously combined with local heat using a hot pack; combined with local cold using a cold pack; and transcutaneous electrical nerve stimulation alone. In each intervention, the knee pain level during walking and standing up from a chair, as well as dynamic balance and gait ability were evaluated immediately before and after a single intervention using the visual analogue scale and the timed up & go test, respectively. [Results] A significant improvement in dynamic balance and gait ability was only observed immediately after transcutaneous electrical nerve stimulation simultaneously combined with local heat application, although the degree of pain relief during standing and walking were comparable among the three interventions. [Conclusion] These results suggest that transcutaneous electrical nerve stimulation simultaneously combined with local heat application can immediately improve not only knee pain during standing and walking but also dynamic balance and gait ability in patients with knee osteoarthritis.

In the present presentation, we report the experimentally and theoretically investigated spatial wavefront conversion properties of an optical vortex (OV) generation system including azo-dye doped liquid crystal (ADDLC) polymer composite and vector beam illuminator, focusing on the abilities of flexibility and achromaticity. Threedimensional anisotropic structure was induced by recording vector beam in ADDLC and it can convert a polarized Gaussian beam into polarized OVs whose topological charge is depending on the structure of anisotropy. The photo-induced anisotropic structure can be re-initialized by turning it off and changing the illuminating polarization pattern of vector beam. Numerical simulations and experimental results showed that our anisotropic structure can generate OV with broadband spectrum.

A polarization-independent terahertz (THz) phase shifter was proposed using a liquid crystal (LC) grating with subwavelength periodic alignment. The LC grating was constructed with one-dimensional periodic planar alignment and was designed based on the effective medium theory. The phase of the transmitted wave was theoretically independent of the polarization state and the phase was shifted by transition from a periodic planar alignment to a homeotropic alignment. The LC grating was fabricated using a nematic LC and photoalignment layers. The easy axes of the photoalignment layers were periodically regulated using a grating photomask with a subwavelength pitch. There was minimal dependence of the obtained phase shift on the polarization state, and the results were in agreement with the theoretical calculations.

Display Omitted We evaluate molecular orientation of photoreactive liquid crystalline polymer P6CAM.Thermal nanoimprinting and graphoepitaxy were used to align P6CAM.P6CAM was reoriented parallel to the line in both processes.Thermal nanoimprinting strongly induced P6CAM orientation compared to graphoepitaxy. Molecular orientation in photoreactive liquid crystals (LCs) can be induced by linearly polarized ultraviolet light and heat. Thermal nanoimprinting has similarities to graphoepitaxy, including using patterned substrates and heating. Diffraction efficiencies were measured to compare the molecular orientation of the photoreactive LC polymer P6CAM induced by thermal nanoimprinting, with that induced by graphoepitaxy. P6CAM was reoriented by graphoepitaxy, but the degree of orientation was much smaller than that induced by thermal nanoimprinting.

The nonlinear propagation characteristics of a radially polarized (RP) beam in uniaxially aligned dye-doped liquid crystal (DDLC) are investigated in experiments and theory. The photothermal effect produces changes in the refractive index of the nonlinear polarization-sensitive medium, in both ordinary and extraordinary directions. The changes promote a self-modulation of the polarization pattern in the incident RP beam as it propagates through the DDLC. The experimental results are explained from theory by modeling the change in the refractive index of the medium. Our results may be applied to spatial polarization modulation, by which an axially symmetric polarized beam is converted into another structured light, such as the full Poincare beam.

A scheme is presented for an optical vortex (OV) generator comprising a uniaxially aligned azo-dye-doped liquid crystal (ADDLC) and a space-variant polarization projection (SVPP) system. The SVPP system consisting of an electro-optic modulator and a micro-electromechanical system projects a time-averaged SVP field equal to a vector beam onto the ADDLC and fabricates a three-dimensional twisted anisotropic structure, which has spatial phase modulation properties from plane to helical shape. The generation of OVs with odd- and even-numbered topological charge is experimentally demonstrated. As a flexible and broadband spatial light modulator, the proposed scheme should be applicable to the research and development of OV applications.

A crossed-fork-shaped polarization grating (crossed-FPG) is presented for use in vector beam division demultiplexing. The crossed-FPG was fabricated in a thin photocrosslinkable liquid crystal polymer film by recording multiple polarization holograms between optical vortices and Gaussian beams that have opposite circular polarizations to each other. The recorded holograms work individually to act as FPG with a polarization-dependent topological charge conversion property that corresponds to a recorded pair of vortices. The feasibility of mode demultiplexing was demonstrated experimentally. The proposed crossed-FPG should be used as a mode demultiplexer for optical communications based on vector beam division multiplexing.

We demonstrated high write endurance of up to 1012 cycles with a pulse write current of 10 ns in a spin current-type (SC) single magnetic tunnel junction (MTJ) element and 8×8 memory array. Furthermore, we demonstrated an accelerated test of failure elements by increasing the write current density. According to cross-sectional TEM images of the failure MTJ elements, one of the failure models is caused only on the spin orbit torque (SOT) line by electrical-open and electrical-short conditions. We concluded that SC-MTJ will have strong write endurance against a high write current if the SOT-line is improved. SC-MTJ offers an alternative to spin transfer torque (STT)–MTJ as a high write endurance magnetic memory.

Axis-selective photoreaction, photoinduced orientation, and formation of surface relief (SR) gratings of liquid crystalline polymethacrylates comprised of N-benzylideneaniline (NBA) derivative side groups are explored. Irradiating with linearly polarized (LP) 313 nm light generates molecular reorientation of the NBA side groups based on the axis-selective trans–cis–trans photoisomerization and photocleavage of the NBA groups. The in-plane order parameter (S) and birefringence (Δn) are ∼0.53 and ∼0.16, respectively. Furthermore, thermally stimulated amplification of the photoinduced optical anisotropy occurs upon exposing films to LP 313 nm light and subsequently annealing in the liquid crystalline temperature range of the material. The amplified S and Δn values are ∼0.71 and ∼0.21, respectively. Finally, polarization holography using 325 nm He–Cd laser beams with various interferometric polarization conditions demonstrates the formation of SR gratings with a molecularly oriented structure based on the per...

Nonlinear light propagation in a dye-doped liquid crystal (LC) was investigated experimentally. A laser beam with wavelength far from the absorption peak of the material was coupled into an LC cell with homogeneous alignment, and the propagation in the cell was observed. When the polarization azimuth of the incident light was orthogonal to the orientation direction of the LC, soliton-like propagation was obtained for milliwatts of light power in spite of the low absorption. We clarified that the observed nonlinearity is due principally to the photothermal effect enhanced by the dye.

The formation of polarization holographic gratings with both optical anisotropy and surface relief (SR) deformation was studied for polymethylmethacrylate with azobenzene side groups. Temporal contributions of isotropic and anisotropic phase gratings were simultaneously determined by observing transitional intensity and polarization states of the diffraction beams and characterizing by means of Jones calculus. To clarify the mechanism of SR deformation, cross sections of SR were characterized based on the optical gradient force model; experimental observations were in good agreement with the theoretical expectation. We clarified that the anisotropic phase change originating in the reorientation of the azobenzene side groups was induced immediately at the beginning of the holographic recording, while the response time of the isotropic phase change originating in the molecular migration due to the optical gradient force was relatively slow.

We investigated the photorefractive performance of the polymer dissolved liquid crystalline composite (PDLCC), in which liquid crystalline polymer and low-molar-mass liquid crystal are miscible without phase separation, doped with three kinds of fullerene derivatives with different length of alkyl groups. The photorefractive performance was improved for the photorefractive PDLCC doped with fullerene derivatives with long length of alkyl groups. The photorefractive grating formation originates in the cooperative reorientation of the liquid crystalline director and the space charge field was estimated using the elastic continuum theory and the field for the PDLCC doped with the functionalized fullerene with longer alkyl side groups was larger than that for the PDLCC doped with conventional fullerene C60.

The blazed vector grating possessing antisymmetric distributions of the birefringence were fabricated by exposing the line-focused linearly polarized ultraviolet light on the photosensitive polymer liquid crystals. The polarization states of the diffraction beams can be highly and widely controlled by designing the blazed structures, and the diffraction properties were well-explained by Jones calculus.

Liquid crystal grating with three-dimensionally modulated anisotropic structure is fabricated by one-step exposure of an empty glass cell whose inner walls are coated with photocrosslinkable polymer liquid crystals to four-beam polarization interference UV beams. The diffraction properties were probed with a 633 nm wavelength laser and a 532 nm wavelength laser which were the coaxial incident. The novel properties, which diffraction directions are threedimensionally different depending on the wavelengths, are realized by the resultant liquid crystal grating. Furthermore, the resultant liquid crystal grating can be also applied to an advanced polarizing beam splitter which opposite circular polarization and linear polarizations are diffracted simultaneously. These diffraction properties were well-explained by Jones calculus. The resultant liquid crystal grating has the plural of the functions of optical elements such as wave plates, polarization beam splitter, dichroic beam splitter, Wollaston/Rochon prism, and tunable wavelength filter. Therefore, the resultant liquid crystal grating can contribute to miniaturization, sophistication, and cost reduction of optical systems using for, such as optical measurement, communication, and information processing.