In-line and off-axis polarization-selective holographic lenses recorded in azopolymer thin films via polarization holography and polarization multiplexing.

Polarization-selective diffractive in-line and off-axis lenses are recorded in azopolymer thin films using polarization holography. A simple, yet efficient, and to the best of our knowledge, new method is used to suppress the surface relief grating formation and to improve the polarization properties of the lenses. The in-line lenses are converging for right circularly polarized (RCP) light and diverging for left circularly polarized (LCP) light. Bifocal off-axis lenses are recorded by polarization multiplexing. By rotating the sample at 90° between the exposures, the two focal points of these lenses are located in orthogonal directions O x and O y, so we can refer to these novel lenses as 2D bifocal polarization holographic lenses. The light intensity in their focuses depends on the reconstructing light polarization. According to the recording scheme, they can either reach maximum intensities simultaneously (for LCP or RCP), or alternatively, one of them can be at maximum for LCP, while the other for RCP. These lenses may be used as polarization controllable optical switches, in the field of self-interference incoherent digital holography or for other photonics applications.

Noise analysis in outdoor dynamic speckle measurement.

The dynamic speckle method (DSM) is an effective tool for the estimation of speed of processes. The speed distribution is encoded in a map built by statistical pointwise processing of time-correlated speckle patterns. For industrial inspection, the outdoor noisy measurement is required. The paper analyzes the efficiency of the DSM in the presence of environmental noise as phase fluctuations due to the lack of vibration isolation and shot noise due to ambient light. The usage of normalized estimates for the case of non-uniform laser illumination is studied. The feasibility of the outdoor measurement has been proven by numerical simulations of noisy image capture and real experiments with test objects. Good agreement has been demonstrated in both the simulation and experiment between the ground truth map and the maps extracted from noisy data.

Risk factors and clinical effects of subclinical leaflet thrombosis after transcatheter aortic valve replacement.

Aims: The number of trans-catheter aortic valve replacement (TAVR) procedure is increasing; However, the incidence of leaflet thrombosis is higher in TAVR than in surgical aortic valve replacement (SAVR). In this study, the risk factors for leaflet thrombosis after TAVR and its effects on hemodynamics and clinical course were investigated. Methods and results: Multidetector computed tomography (MDCT) was performed at 1year after TAVR in 94 patients from January 2015 to October 2020 at Samsung Medical Center in South Korea. Among the 94 patients, subclinical leaflet thrombosis occurred in 20 patients, and risk factors were analyzed. In addition, the difference in aortic valve (AV) hemodynamics between the two groups was examined and clinical outcomes compared. Indexed mean sinus of Valsalva (SOV) diameter, AV calcium volume, and post-procedure effective orifice area (EOA) were predictive of subclinical leaflet thrombosis with the area under the curve (AUC) value of 0.670 (P-value = 0.020), 0.695 (P-value = 0.013), and 0.665 (P-value = 0.031), respectively. In echocardiography performed at the time of follow-up CT, the value of AV max velocity and AV mean pressure gradient were higher in the thrombosis group and the EOA and Doppler velocity index values were lower in the thrombosis group than in the no thrombosis group. Clinical outcome was not significantly different between the two groups (log-rank P-value = 0.26). Conclusion: Larger indexed SOV diameter, higher AV calcium volume, and smaller post-procedure AV EOA were risk factors for subclinical leaflet thrombosis after TAVR. Subclinical leaflet thrombosis has a benign course when properly managed.

Wide-viewing holographic stereogram based on self-interference incoherent digital holography.

We propose a holographic stereogram synthesis method which uses holograms that are optically captured by self-interference incoherent digital holography (SIDH) based on a geometric phase lens. SIDH is a promising solution for hologram acquisition under low-coherence lighting condition. A mechanical scanning system is constructed to acquire multiple perspective holograms. Numerical simulations and experimental analyses conducted using high-resolution diffractive optical element demonstrate that the proposed method can produce a wide-viewing hologram which can realize realistic 3D scenarios with depth cues such as accommodation and motion parallax. The future objectives include the implementation of a multiple-camera system for holographic videos.

Effect of Wire Jailing at Side Branch in 1-Stent Strategy for Coronary Bifurcation Lesions.

OBJECTIVES: This study aimed to determine whether side branch (SB) wire jailing before main vessel (MV) stenting could prevent SB occlusion after the 1-stent strategy for bifurcation percutaneous coronary intervention. BACKGROUND: The benefits of SB wire jailing in the 1-stent strategy remain unclear. METHODS: From the COBIS (Coronary Bifurcation Stenting) III registry, 1,890 patients with bifurcation lesions who underwent the 1-stent strategy using second-generation drug-eluting stents were identified and classified into 2 groups according to the use of SB wire jailing: wire jailing (n = 819) and non-wire jailing (n = 1,071). The incidence of SB occlusion (Thrombolysis In Myocardial Infarction flow grade <3) and target lesion failure (cardiac death, myocardial infarction, or target lesion revascularization) was compared. RESULTS: The incidence of final SB occlusion was not significantly different between wire jailing (1.8%) vs non-wire jailing (2.9%; P = 0.182). However, wire jailing at the SB was a significant protective factor for SB occlusion after MV stenting on multivariate analysis and was significantly associated with a lower incidence of SB occlusion in patients with significant stenoses (≥60%) at the SB (5.1% vs 11.3%; odds ratio: 0.42; 95% CI: 0.19-0.89; P = 0.028) or MV (3.1% vs 6.2%; odds ratio: 0.49; 95% CI: 0.24-0.95; P = 0.039). During follow-up (median 52 months), the incidence of target lesion failure was not significantly different between wire jailing and non-wire jailing (7.6% vs 6.3%; P = 0.343). CONCLUSIONS: During bifurcation percutaneous coronary intervention with the 1-stent strategy, wire jailing at the SB was associated with a lower rate of final SB occlusion following MV stenting in patients with severe stenoses at the SB or MV but not with overall bifurcation lesions. Long-term clinical outcomes were comparable between the 2 groups.

Digital Incoherent Compressive Holography Using a Geometric Phase Metalens.

We propose a compressive self-interference incoherent digital holography (SIDH) with a geometric phase metalens for section-wise holographic object reconstruction. We specify the details of the SIDH with a geometric phase metalens design that covers the visible wavelength band, analyze a spatial distortion problem in the SIDH and address a process of a compressive holographic section-wise reconstruction with analytic spatial calibration. The metalens allows us to realize a compressive SIDH system in the visible wavelength band using an image sensor with relatively low bandwidth. The operation of the proposed compressive SIDH is verified through numerical simulations.

Coronary microcirculation assessment using functional angiography: Development of a wire-free method applicable to conventional coronary angiograms.

OBJECTIVES: We aimed to develop a novel wire- and adenosine-free microcirculatory resistive index from functional angiography (angio-IMR) to estimate coronary microcirculatory resistance, and to investigate how this method can improve clinical interpretation of physiological stenosis assessment with quantitative flow ratio (QFR). BACKGROUND: Hyperemic index of coronary microcirculatory resistance (IMR) is a widely used tool to assess microcirculatory dysfunction. However, the need of dedicated intracoronary wire and hyperemia limits its adoption in clinical practice. METHODS: We performed our study in two separate stages: (1) development of a formula (angio-IMR) to estimate IMR from resting angiograms and aortic pressure (Pa), and (2) validation of the method in a clinical population using invasively measured IMR as reference. Additionally, QFR diagnostic performance was assessed considering angio-IMR values. RESULTS: We developed the formula: angio-IMR = (Pa-[0.1*Pa])*QFR*e-Tmn (where e-Tmn is an estimation of hyperaemic mean transit time) and validated it in 115 vessels (104 patients). Angio-IMR correlated well with IMR (Spearman's rho = 0.70, p < 0.001). Sensitivity, specificity, positive and negative predictive value, accuracy and area under the curve of angio-IMR to predict IMR were 87.5% (73.2-95.8), 85.3% (75.3-92.4), 76.1% (64.5-84.8), 92.8% (84.9-96.7), 85% and 0.90 (0.83-0.95), respectively. False positive QFR measurements decreased from 19.5% to 8.5% when angio-IMR was incorporated into the QFR interpretation workflow. CONCLUSIONS: Estimation of IMR without physiology wire and adenosine is feasible. Coronary microcirculatory dysfunction causing high IMR can be ruled-out with high confidence in vessels with low angio-IMR. Awareness of angio-IMR contributes to a better clinical interpretation of functional stenosis assessment with QFR.

The Graft Insertion Length in the Femoral Tunnel During Anterior Cruciate Ligament Reconstruction With Suspensory Fixation and Tibialis Anterior Allograft Does Not Affect Surgical Outcomes but Is Negatively Correlated With Tunnel Widening.

PURPOSE: To investigate the surgical outcomes of anterior cruciate ligament (ACL) reconstruction using a low-dose irradiated tibialis anterior allograft with a fixed-loop cortical suspension device for the femur based on the graft insertion length (GIL) in the femoral tunnel. METHODS: Between January 2010 and January 2018, the medical records of consecutive patients who underwent arthroscopic ACL reconstruction with a tibialis anterior allograft fixed with the EndoButton CL for the femur and who had at least 2 years of follow-up were retrospectively evaluated. Patients were classified into 3 groups based on the GIL in the femoral tunnel (group 1, GIL < 15 mm; group 2, GIL of 15-20 mm; and group 3, GIL > 20 mm), and their functional scores, knee laxity, and radiographic parameters were evaluated. RESULTS: A total of 91 patients were analyzed. There were no statistically significant differences in the functional scores and knee laxity between the 3 groups at 2 years postoperatively. However, significant differences were observed in tunnel widening at 1 year postoperatively in the femur (P = .045 for absolute value and P = .004 for relative value) and the tibia (P = .014 for absolute value and P = .012 for relative value), revealing that both the femoral and tibial tunnels widened as the GIL decreased. Additional linear regression analyses were performed to identify whether the GIL independently affects tunnel widening. Consequently, the femoral tunnel depth, tunnel diameter, and GIL were found to independently influence femoral tunnel widening (P = .008, P = .019, and P < .001, respectively), whereas the tunnel diameter and GIL affected tibial tunnel widening (P < .001 and P = .004, respectively). CONCLUSIONS: The GIL in the femoral tunnel during ACL reconstruction using a tibialis anterior allograft with a fixed-loop cortical suspension device for the femur has no significant association with the postoperative functional outcomes and knee laxity, but it has a negative correlation with tunnel widening in the femur and the tibia. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Sex difference in long-term clinical outcomes after percutaneous coronary intervention: A propensity-matched analysis of National Health Insurance data in Republic of Korea.

OBJECTIVE: We investigated the gender difference in the 5-year outcome after percutaneous coronary intervention (PCI) using an unselected population data. BACKGROUND: Sex-specific outcome after percutaneous coronary intervention (PCI) is not consistent among studies. METHODS: A total of 48,783 patients were enrolled from a Korean nationwide cohort of PCI in year 2011. Outcomes adjusted with age and propensity for clinical characteristics were compared. Primary outcome was 5-year cumulative incidence of all-cause death. Nonfatal major adverse clinical event (MACE) consisting of revascularization, shock, or stroke was also assessed. RESULTS: In unadjusted analysis, women were older and had higher frequency of comorbidities including hypertension, hyperlipidemia, and diabetes compared to men (p < .001, all). Women had higher 5-year death risk than men (21.8 vs. 17.3%; hazard ratio [HR] 1.29, 95% confidential interval [CI] 1.23-1.34). In propensity score-matched analysis (N = 28,924), women had lower 5-year death risk (20.2 vs. 26.1%, HR 0.75, 95% CI 0.71-0.78). This lower death risk in women was consistent in subgroup analyses of age, risk factors, and clinical diagnosis including angina or acute myocardial infarction (p < .05, all). CONCLUSIONS: Older age and more common comorbidities in women contributed to the apparent worse outcome after PCI in women. After adjusting these disadvantages, women had better outcome after PCI than men.

Michelson-interferometric-configuration-based incoherent digital holography with a geometric phase shifter.

The phase-shifting method is a simple and efficient approach to extract complex hologram information free of bias and twin-image noise. In this study, the geometric phase-shifting method is utilized for a self-interference incoherent digital holographic recording system based on the Michelson-type interferometer. The phase-shifting module consists of a horizontal polarizer, and two achromatic quarter-wave plates are employed inside the interferometer, replacing conventional phase-shifting devices, such as the piezo-actuated mirror. Since the phase-shifting amount of the introduced method herein is theoretical, regardless of the input wavelength, the simultaneous recording of step-wise phase-shifted interferograms for different color channels is available. Therefore, the multi-color hologram recording is achieved with fewer numbers of exposures. The demonstration of multi-color hologram recording and reconstruction are presented to validate the proposed idea.

Compact self-interference incoherent digital holographic camera system with real-time operation.

The video recording-capable compact incoherent digital holographic camera system is proposed. The system consists of the linear polarizer, convex lens, geometric phase lens, and the polarized image sensor. The Fresnel hologram is recorded by this simple configuration in real time. The system parameters are analyzed and evaluated to record a better-quality hologram in a compact form-factor. The real-time holographic recording and its digitally reconstructed video playback are demonstrated with the proposed system.

Achromatic phase shifting self-interference incoherent digital holography using linear polarizer and geometric phase lens.

A simple Fresnel-type self-interference incoherent digital holographic recording system is proposed. The main part of the system consists of the two linear polarizers and geometric phase lens. The geometric phase lens is employed as a polarization selective common-path interferometer. One of the polarizers is rotated by the motor and serves as a phase-shifter with the geometric phase lens, to eliminate the bias and twin image noise. A topological phase is obtained by the relative angle between the polarizer and geometric phase lens. Since this phase shifting method does not depend on the change of the optical path length, the phase shifting performance is almost constant in the broad spectral range. Using the proposed achromatic phase shifting method, a simultaneous three-color phase shifting digital hologram recording under the incoherent light source is demonstrated.

Self-interference digital holography with a geometric-phase hologram lens.

Self-interference digital holography (SIDH) is actively studied because the hologram acquisition under the incoherent illumination condition is available. The key component in this system is wavefront modulating optics, which modulates an incoming object wave into two different wavefront curvatures. In this Letter, the geometric-phase hologram lens is introduced in the SIDH system to perform as a polarization-sensitive wavefront modulator and a single-path beam splitter. This special optics has several features, such as high transparency, a modulation efficiency up to 99%, a thinness of a few millimeters, and a flat structure. The demonstration system is devised, and the numerical reconstruction results from an acquired complex hologram are presented.

Optical defocus noise suppressing by using a pinhole-polarizer in Fresnel incoherent correlation holography.

We propose the method that suppresses the defocus noise optically in the Fresnel incoherent correlation holographic system using a pinhole-polarizer (PP), which is made by punching a pinhole on the linear polarizer. The system configuration of this suggestion is based on the original system with optical-sectioning capability, which is realized by presenting the phase-pinhole on the phase-only spatial light modulator. In our system, the phase-pinhole is replaced with a PP. The replaced component is no longer programmable yet provides an affordable, simple, and light-efficient system configuration. The feasibility of the system with the PP is analyzed and demonstrated.

Real object pickup method of integral imaging using offset lens array.

We propose the pickup system of integral imaging using the offset lens array (OLA), which is a useful optical component for both the pickup and display processes. The main purpose of our system is resolving the pseudoscopic image problem of integral imaging. Also, the flipped image of integral imaging that has the wrong perspective information can be removed by adding an external barrier in the display process. In this paper, the above properties are explained in detail, and the experimental results to verify the feasibility of the proposed system are presented. We are certain that our system can also be applied to other various pickup systems based on integral imaging.

Analysis on expressible depth range of integral imaging based on degree of voxel overlap.

This paper proposes a practical method to analyze the expressible depth range of an integral imaging system based on image blur at defocused depths, which is one of the most noticeable image degradations, caused by overlaps among voxels in both the real and focused mode. In order to obtain the preferably precise area of overlaps among voxels at each depth, display pixels are regarded as surface light sources in the process of voxel size calculation. As a criterion for determining the range, we determine the tolerable limit of the overlaps among voxels to be at least resolved from each other. Based on this principle, several mathematical expressions about the expressible depth range can be derived in both the real mode and focused mode, and their feasibilities are demonstrated by several experiments. The analyses are processed based on both wave optics and ray optics.

Effects of high voltage nanosecond pulsed plasma and micro DBD plasma on seed germination, growth development and physiological activities in spinach.

In this study, we analyzed seed germination, seedling growth, and physiological aspects after treatment with high voltage nanosecond pulsed plasma and micro DBD plasma in spinach (Spinacia oleracea L.), a green leafy vegetable known to have low germination rate. Both germination and dry weight of seedlings increased after high voltage pulse shots were applied to spinach seeds. However seeds treated with many shots (10 shots) showed a decrease in germination rate and seedling growth. Seeds treated with air DBD plasma exhibited slightly higher germination and subsequent seedling growth than those treated with N2 plasma. Seed surface was degenerated after treated with high voltage pulsed plasma and micro DBD plasma but no significant difference in the degree of degeneration was observed among micro DBD plasma treatment time. Level of GA3 hormone and mRNA expression of an amylolytic enzyme-related gene in seeds were elevated 1 day after treatment with high voltage pulsed plasma. The relative amount of chlorophyll and total polyphenols in spinach seedlings grown from seeds treated with air DBD plasma was increased in 30 s, 1 min, and 3 min treatments. Taken together, our results suggest a possibility that plasma can enhance seed germination by triggering biochemical processes in seeds.

Measurement of accommodation response of human eye to integral floating display.

The dioptric responses of human eyes to floating images at different depths reconstructed by an integral floating display are measured with an open-field autorefractor and analyzed according to observer recognition of the accommodation depth cue. Two targets are randomly presented approximately 1.75 D from the observers and have a separation of 0.15 D, corresponding to approximately 5 cm. Two subjects participate, and over 500 responses are measured during each experimental trial. The frequency distribution profiles of the responses to targets at different locations are obtained and analyzed. The results confirm that the subjects focused on the floating targets and not on the surface of the optical component. In this paper, an analysis of the separation between the peaks of the frequency distribution profiles is presented that confirms that the integral floating display could induce the accommodation response to provide the corresponding depth stimulus.

Differential Inactivation of Fungal Spores in Water and on Seeds by Ozone and Arc Discharge Plasma.

Seed sterilization is essential for preventing seed borne fungal diseases. Sterilization tools based on physical technologies have recently received much attention. However, available information is very limited in terms of efficiency, safety, and mode of action. In this study, we have examined antifungal activity of ozone and arc discharge plasma, potential tools for seed sterilization. In our results, ozone and arc discharge plasma have shown differential antifungal effects, depending on the environment associated with fungal spores (freely submerged in water or infected seeds). Ozone inactivates Fusarium fujikuroi (fungus causing rice bakanae disease) spores submerged in water more efficiently than arc discharge plasma. However, fungal spores associated with or infecting rice seeds are more effectively deactivated by arc discharge plasma. ROS generated in water by ozone may function as a powerful fungicidal factor. On the other hand, shockwave generated from arc discharge plasma may have greatly contributed to antifungal effects on fungus associated with rice seeds. In support of this notion, addition of ultrasonic wave in ozone generating water has greatly increased the efficiency of seed disinfection.