Ultrathin, polarization-independent, and focus-tunable liquid crystal diffractive lens for augmented reality

Despite the recent advances in augmented reality (AR), which has shown the potential to significantly impact on our daily lives by offering a new way to manipulate and interact with virtual information, minimizing visual discomfort due to the vergence-accommodation conflict remains a challenge. Emerging AR technologies often exploit focus-tunable optics to address this problem. Although they demonstrated improved depth perception by enabling proper focus cues, a bulky form factor of focus-tunable optics prevents their use in the form of a pair of eyeglasses. Herein, we describe an ultrathin, focus-tunable liquid crystal (LC) diffractive lens with a large aperture, a low weight, and a low operating voltage. In addition, we show that the polarization dependence of the lens, which is an inherent optical property of LC lenses, can be eliminated using birefringent thin films as substrates and by aligning the optical axes of the birefringent substrates and LC at a specific angle. The polarization independence eliminates the need for a polarizer, thus further reducing the form factor of the optical system. Next, we demonstrate a prototype of AR glasses with addressable focal planes using the ultrathin lens. The prototype AR glasses can adjust the accommodation distance of the virtual image, mitigating the vergence-accommodation conflict without substantially compromising the form factor or image quality. This research on ultrathin lens technology shows promising potential for developing compact optical displays in various applications.Comment: 23 pages, 9 figure

Osseointegration of Implants Surface-Treated with Various Diameters of TiO 2

The aim of this study was to evaluate the osseointegration of implants which were surface-treated with various diameters of TiO2 nanotubes (30 nm, 70 nm, and 100 nm) in rabbit. Resorbable blast media (RBM) surfaced implants (Osstem, Busan, Korea) 3.5 mm in diameter and 8.5 mm in length were designated as the control group and the implants surface-treated with various diameters of nanotubes (30 nm, 70 nm, and 100 nm) with the same shapes were designated as the experimental groups. The implants were maintained unloaded for 4 and 12 weeks. After this period, the animals were sacrificed and micro-CT analysis, histomorphometric analysis (bone to implant contact (BIC), bone volume (BV)), and removal torque test were performed. Micro-CT analysis, histomorphometric analysis, and removal torque test results all showed the similar pattern, showing that 70 nm experimental group had the highest value at 4 weeks while 30 nm experimental group had the highest value at 12 weeks. Therefore, on the basis of the results above, it can be concluded that 30 nm and 70 nm TiO2 nanotubes may have positive effects on osteogenesis and osseointegration depending on the healing time

The Management of Cardiovascular Abnormalities in Patient With LEOPARD Syndrome

LEOPARD syndrome (LS) is a rare hereditary disorder in Asian countries. This syndrome consists of multiple systemic abnormalities. In particular, characteristic cardiovascular effects in LS may include variable clinical manifestations from benign to life-threatening courses. The cardiac effects of this syndrome consist of left ventricular hypertrophy (LVH), pulmonary stenosis (PS), coronary artery dilatation and electrocardiogram(ECG) abnormalities. Since there are few LS patients who have undergone a complete cardiovascular evaluation, the nature and clinical prognosis of cardiovascular abnormalities in this syndrome remain uncertain. Also, there have been few reports on therapeutic strategies for cardiovascular abnormalities in LS. Here we describe a case of LS who presented with multiple cardiovascular problems and underwent successful surgical and medical treatment

The Evaluation of Osseointegration of Dental Implant Surface with Different Size of TiO 2

With the development of nanotechnology, many researches have shown that nanometer-scaled materials especially TiO2 nanotube have a positive effect on cellular behavior and surface characteristics of implant, which are considered to be crucial factors in osseointegration. However, it has not yet been verified which nanotube size is effective in osseointegration in vivo. The aim of this study was to evaluate the effect of implant surface-treated with different size of TiO2 nanotubes on osseointegration in rat femur. The customized implants (threaded and nonthreaded type), surface-treated with different diameter of TiO2 nanotubes (30 nm, 50 nm, 70 nm, and 100 nm nanotube), were placed on both sides of the femur of 50 male Sprague-Dawley rats (6 weeks old). Rats were sacrificed at 2 and 6 weeks following surgery; then the specimens were collected by perfusion fixation and the osseointegration of implants was evaluated by radiographic and histologic analyses and removal torque value test. The mean of bone area (%) and the mean of removal torque were different in each group, indicating that the difference in TiO2 nanotube size may influence new bone formation and osseointegration in rats

Validation of the finger counting method using the Monte Carlo simulation

Purpose The dose of drug and the size of instrument are determined based on children’s weight. We aimed to validate the finger counting method (FCM) for weight estimation in Korean children using the Monte Carlo simulation. Methods We estimated the weight of Korean children aged 1 to 9 years by the FCM. These measurements were compared with the weight extracted by the Monte Carlo simulation applied to the “2007 Korean Children and Adolescents Growth Standard.” Pearson correlation coefficients (r) were measured to assess the correlation between the weight extracted by the simulation and that estimated by FCM. Bland-Altman analyses were performed to assess the agreement between the weight extracted by the simulation and that estimated by FCM and 2 other well-known pediatric weight estimation formulas (the Advanced Pediatric Life Support and Luscombe formulas). Results Data regarding 9,000 children’s weight selected by age and gender was randomly extracted using the simulation. We found a positive correlation between the weight estimated by the FCM and the weight extracted (in boys, r = 0.896, P < 0.001; in girls, r = 0.899, P < 0.001). The FCM tended to underestimate weight in the children aged 7 years or old. Conclusion This article suggests the usefulness of FCM in weight estimation, particularly in children younger than 7 years. With appreciation of the limitation in older children, the FCM could be applied to emergency practice

Unveiling the key factor for the phase reconstruction and exsolved metallic particle distribution in perovskites

To significantly increase the amount of exsolved particles, the complete phase reconstruction from simple perovskite to Ruddlesden-Popper (R-P) perovskite is greatly desirable. However, a comprehensive understanding of key parameters affecting the phase reconstruction to R-P perovskite is still unexplored. Herein, we propose the Gibbs free energy for oxygen vacancy formation in Pr-0.5(Ba/Sr)(0.5)TO3-delta (T = Mn, Fe, Co, and Ni) as the important factor in determining the type of phase reconstruction. Furthermore, using in-situ temperature &amp; environment-controlled X-ray diffraction measurements, we report the phase diagram and optimum &apos;x&apos; range required for the complete phase reconstruction to R-P perovskite in Pr0.5Ba0.5-xSrxFeO3-delta system. Among the Pr0.5Ba0.5-xSrxFeO3-delta, (Pr0.5Ba0.2Sr0.3)(2)FeO4+delta - Fe metal demonstrates the smallest size of exsolved Fe metal particles when the phase reconstruction occurs under reducing condition. The exsolved nano-Fe metal particles exhibit high particle density and are well-distributed on the perovskite surface, showing great catalytic activity in fuel cell and syngas production. The complete phase reconstruction to Ruddlesden-Popper perovskite is greatly desirable to increase the exsolved particle distribution. Here, the authors report a key factor for the complete phase reconstruction in perovskites, leading to good catalytic activity in fuel cell and syngas production

Stenting of the Left Main Coronary Artery in a Patient With Takayasu's Arteritis

Management of Takayasu's arteritis of the left main coronary artery (LMCA) is difficult because of the possibility of restenosis. Clinically significant stenotic lesions must be considered anatomical correlation. Many studies have reported that the management of stenotic lesions of the LMCA with endoluminal stenting and balloon angioplasty and de-novo stenting is safe and effective for patients with Takayasu's arteritis. We report the case of a patient with Takayasu's arteritis of the LMCA. The patient had undergone two consecutive percutaneous coronary interventions because of recurrent restenosis of in-stent lesions, and eventually underwent coronary artery bypass graft (CABG) surgery for myocardial infarction in the same lesion. We suggested treatment with CABG because the pathophysiology of Takayasu's arteritis is different from that of atherosclerotic stenosis

Variation block-based genomics method for crop plants

BACKGROUND: In contrast with wild species, cultivated crop genomes consist of reshuffled recombination blocks, which occurred by crossing and selection processes. Accordingly, recombination block-based genomics analysis can be an effective approach for the screening of target loci for agricultural traits. RESULTS: We propose the variation block method, which is a three-step process for recombination block detection and comparison. The first step is to detect variations by comparing the short-read DNA sequences of the cultivar to the reference genome of the target crop. Next, sequence blocks with variation patterns are examined and defined. The boundaries between the variation-containing sequence blocks are regarded as recombination sites. All the assumed recombination sites in the cultivar set are used to split the genomes, and the resulting sequence regions are termed variation blocks. Finally, the genomes are compared using the variation blocks. The variation block method identified recurring recombination blocks accurately and successfully represented block-level diversities in the publicly available genomes of 31 soybean and 23 rice accessions. The practicality of this approach was demonstrated by the identification of a putative locus determining soybean hilum color. CONCLUSIONS: We suggest that the variation block method is an efficient genomics method for the recombination block-level comparison of crop genomes. We expect that this method will facilitate the development of crop genomics by bringing genomics technologies to the field of crop breeding