HoloSR: deep learning-based super-resolution for real-time high-resolution computer-generated holograms.

This study presents HoloSR, a novel deep learning-based super-resolution approach designed to produce high-resolution computer-generated holograms from low-resolution RGBD images, enabling the real-time production of realistic three-dimensional images. The HoloSR combines the enhanced deep super-resolution network with resize and convolution layers, facilitating the direct generation of high-resolution computer-generated holograms without requiring additional interpolation. Various upscaling scales, extending up to ×4, are evaluated to assess the performance of our method. Quantitative metrics such as structural similarity and peak signal-to-noise ratio are employed to measure the quality of the reconstructed images. Our simulation and experimental results demonstrate that HoloSR successfully achieves super-resolution by generating high-resolution holograms from low-resolution RGBD inputs with supervised and unsupervised learning.

The chronological changes in the seroprevalence of anti-hepatitis A virus IgG from 2005 to 2019: Experience at four centers in the capital area of South Korea.

Although universal vaccination has been administered to toddlers, South Korea has had periodic nationwide outbreaks of acute hepatitis A since the late 2000s. We examined the chronological changes in the seroprevalence of anti-hepatitis A virus (HAV) immunoglobulin G (IgG) over the past 15 years (2005-2019). We retrospectively collected data from 45,632 subjects who underwent anti-HAV IgG testing without evidence of acute HAV infection at four centers in the capital area of South Korea between January 2005 and December 2019. The seroprevalence of anti-HAV IgG was analyzed according to age and compared among seven age groups and five time periods. Additionally, age-period-cohort analyses were used to identify the age, period, and cohort effects of the seroprevalence of anti-HAV IgG. The mean age of the enrolled subjects was 39.2 ±â€…19.2 years, and the average anti-HAV IgG positivity rate was 66.4%. During the 15 years, the seroprevalence of anti-HAV IgG in people aged 0 to 19 years significantly increased over time (P < .001). In people aged 20 to 29 years, the seroprevalence slightly decreased to that of the early 2010s (31.3% in 2005-2007 to 19.7% in 2011-2013) but rebounded to 39.5% in 2017 to 2019. In contrast, the seroprevalence of anti-HAV IgG in those aged 30 to 49 years decreased over time (P < .001). The seroprevalence of anti-HAV IgG in those aged 20 to 39 years in 2017 to 2019 was still less than 40%. In addition, the seroprevalence of anti-HAV IgG in people aged 50 to 59 years has recently decreased. Since the introduction of the universal vaccination, the seroprevalence of anti-HAV IgG in children and young adults has gradually increased. However, the seroprevalence of anti-HAV IgG in people in their 20s remains low, and the seroprevalence of anti-HAV IgG in people in their 30s and 40s is gradually decreasing. Therefore, a new strategy for HAV vaccination is needed for those in their 20s to 40s.

Accelerating a spatially varying aberration correction of holographic displays with low-rank approximation.

Correction of spatially varying aberrations in holographic displays often requires intractable computational loads. In this Letter, we introduce a low-rank approximation method that decomposes sub-holograms into a small number of modes, thereby reformulating the computer-generated hologram calculation into a summation of a few convolutions. The low-rank approximation is carried out with two different algorithms: the Karhunen-Loeve transform as the optimum solution with respect to the mean-squared error criterion and a novel, to the best of our knowledge, optimization method to provide uniform image quality over the entire field of view. The proposed method is two orders of magnitude faster than the conventional point-wise integration method in our experimental setup, with comparable image quality.

Platelet-to-White Blood Cell Ratio Is Associated with Adverse Outcomes in Cirrhotic Patients with Acute Deterioration.

Background: The platelet-to-white blood cell ratio (PWR) is a hematologic marker of the systemic inflammatory response. Recently, the PWR was revealed to have a role as an independent prognostic factor for mortality in patients with hepatitis B virus (HBV)-related acute-on-chronic failure (ACLF) and HBV-related liver cirrhosis (LC) with acute decompensation (AD). However, the prognostic role of the PWR still needs to be investigated in LC patients with AD. In this study, we analyzed whether the PWR could stratify the risk of adverse outcomes (death or liver transplantation (LT)) in these patients. Methods: A prospective cohort of 1670 patients with AD of liver cirrhosis ((age: 55.2 ± 7.8, male = 1226 (73.4%)) was enrolled and evaluated for 28-day and overall adverse outcomes. Results: During a median follow-up of 8.0 months (range, 1.9−15.5 months), 424 (25.4%) patients had adverse outcomes (death = 377, LT = 47). The most common etiology of LC was alcohol use (69.7%). The adverse outcome rate was higher for patients with a PWR ≤ 12.1 than for those with a PWR > 12.1. A lower PWR level was a prognostic factor for 28-day adverse outcomes (PWR: hazard ratio 1.707, p = 0.034) when adjusted for the etiology of cirrhosis, infection, ACLF, and the MELD score. In the subgroup analysis, the PWR level stratified the risk of 28-day adverse outcomes regardless of the presence of ACLF or the main form of AD but not for those with bacterial infection. Conclusions: A lower PWR level was associated with 28-day adverse outcomes, indicating that the PWR level can be a useful and simple tool for stratifying the risk of 28-day adverse outcomes in LC patients with AD.

Expanding energy envelope in holographic display via mutually coherent multi-directional illumination.

Holographic display is considered as the most promising three-dimensional (3D) display due to its unique feature of reconstructing arbitrary wavefronts. However, the limited étendue, which hinders the immersive experience of observers, remains a major unresolved issue in holographic display technique. In this paper, we propose a novel approach to tweak the constraints of étendue by expanding the energy envelope in holographic display via mutually coherent multi-illumination. The proposed concept contains both a light source design for generating a mutually coherent multi-directional wave and a computer-generated hologram optimization framework for providing high-resolution 3D holograms. To verify the proposed approach, a benchtop prototype of a holographic near-eye display providing an intrinsic large exit-pupil is implemented. The experimental results clearly show that the exit-pupil is effectively expanded by four times and an appropriate viewpoint image is reconstructed according to the view position.

Learning-based compensation of spatially varying aberrations for holographic display [Invited].

We propose a hologram generation technique to compensate for spatially varying aberrations of holographic displays through machine learning. The image quality of the holographic display is severely degraded when there exist optical aberrations due to misalignment of optical elements or off-axis projection. One of the main advantages of holographic display is that aberrations can be compensated for without additional optical elements. Conventionally, computer-generated holograms for compensation are synthesized through a point-wise integration method, which requires large computational loads. Here, we propose to replace the integration with a combination of fast-Fourier-transform-based convolutions and forward computation of a deep neural network. The point-wise integration method took approximately 95.14 s to generate a hologram of 1024×1024pixels, while the proposed method took about 0.13 s, which corresponds to ×732 computation speed improvement. Furthermore, the aberration compensation by the proposed method is verified through experiments.

Optimization of computer-generated holograms featuring phase randomness control.

In this Letter, we introduce a computer-generated hologram (CGH) optimization technique that can control the randomness of the reconstructed phase. The phase randomness significantly affects the eyebox size and depth of field in holographic near-eye displays. Our proposal is to synthesize the CGH through the sum of two terms computed from the target scene with a random phase. We set a weighting pattern for summation as the optimization variable, which enables the CGH to reflect the random phase during optimization. We evaluate the proposed algorithm on single-depth and multi-depth contents, and the performance is validated via simulations and experiments.

Vision-correcting holographic display: evaluation of aberration correcting hologram.

Vision-correcting displays are key to achieving physical and physiological comforts to the users with refractive errors. Among such displays are holographic displays, which can provide a high-resolution vision-adaptive solution with complex wavefront modulation. However, none of the existing hologram rendering techniques have considered the optical properties of the human eye nor evaluated the significance of vision correction. Here, we introduce vision-correcting holographic display and hologram acquisition that integrates user-dependent prescriptions and a physical model of the optics, enabling the correction of on-axis and off-axis aberrations. Experimental and empirical evaluations of the vision-correcting holographic displays show the competence of holographic corrections over the conventional vision correction solutions.

Light source optimization for partially coherent holographic displays with consideration of speckle contrast, resolution, and depth of field.

Speckle reduction is an important topic in holographic displays as speckles not only reduce signal-to-noise ratio but also possess an eye-safety issue. Despite thorough exploration of speckle reduction methods using partially coherent light sources, the trade-off involved by the partial coherence has not been thoroughly discussed. Here, we introduce theoretical models that quantify the effects of partial coherence on the resolution and the speckle contrast. The theoretical models allow us to find an optimal light source that maximizes the speckle reduction while minimizing the decline of the other terms. We implement benchtop prototypes of partially coherent holographic displays using the optimal light source, and verify the theoretical models via simulation and experiment. We also present a criterion to evaluate the depth of field in partially coherent holographic displays. We conclude with a discussion about approximations and limitations inherent in the theoretical models.

Aberration-corrected full-color holographic augmented reality near-eye display using a Pancharatnam-Berry phase lens.

We present a full-color holographic augmented reality near-eye display using a Pancharatnam-Berry phase lens (PBP lens) and its aberration correction method. Monochromatic and chromatic aberrations of the PBP lens are corrected by utilizing complex wavefront modulation of the holographic display. A hologram calculation method incorporating the phase profile of the PBP lens is proposed to correct the monochromatic aberration. Moreover, the chromatic aberration is corrected by warping the image using the mapping function obtained from ray tracing. The proposed system is demonstrated with the benchtop prototype, and the experimental results show that the proposed system offers 50° field of view full-color holographic images without optical aberrations.

Speckle reduced holographic displays using tomographic synthesis.

Despite significant merit of depth representation, holographic displays have a considerable limitation: speckle. Here, we present speckle reduced holographic displays using an engineered light source with angle diversity for speckle reduction. The level of angle diversity is optimized with consideration of resolution, speckle contrast, and depth of field. To extend the depth of field sacrificed for speckle reduction, we apply tomographic synthesis, exploiting synchronization of a local illumination module and a tunable-focus lens. We implement a benchtop prototype to verify the proposed method, which reduces the speckle contrast averagely by 37.8% while preserving resolution and 4.0 diopter depth of field.

Speckle reduced holographic displays using tomographic synthesis: publisher's note.

This publisher's note contains corrections to Opt. Lett.45, 4686 (2020)OPLEDP0146-959210.1364/OL.399623.

Preconditioning with repetitive electromagnetic stimulation enhances activity of bone marrow mesenchymal stem cells from elderly patients through Erk1/2 via nitric oxide.

Use of bone marrow aspirate (BMA) is a clinically advantageous cell therapeutic that bypasses the need for elaborate ex vivo cell culturing. However, a low level of bone marrow­mesenchymal stem cells (BM­MSCs) in the BMA and weak survival rate of these cells post­transplantation entails an insufficient efficacy in vivo. Moreover, stem cell activity in BMA is impaired by age or background diseases. Thus, in order to enrich the BM­MSC pool and improve cell survival, novel cell preconditioning technologies are required. In this study, it has been revealed that the pretreatment of repetitive electromagnetic stimulation (rEMS) is capable of enhancing fibroblastic colony­forming units and cell proliferation in the BM­MSCs, possibly via transient nitric oxide production and extracellular signal regulated kinase 1/2 activation. Notably, this effect was more apparent in stem cells isolated from older patients than from young patients. Furthermore, the rEMS­pretreated cells showed ~53% higher cell survival, compared with the untreated cells, after cell transplantation in mice with no signs of tumorigenesis. Collectively, transient rEMS preconditioning could be utilized to enhance the activity of stem cells and thus, application of rEMS preconditioning to stem cells isolated from older patients is expected to improve the therapeutic effect of stem cells.

Augmented reality near-eye display using Pancharatnam-Berry phase lenses.

An augmented reality (AR) near-eye display using Pancharatnam-Berry (PB) phase lenses is proposed. PB phase lenses provide different optical effects depending on the polarization state of the incident light. By exploiting this characteristic, it is possible to manufacture an AR combiner with a small form factor and a large numerical aperture value. The AR combiner adopted in the proposed system operates as a convex lens for right-handed circularly polarized light and operates as transparent glass for left-handed circularly polarized light. By merging this combiner with a transparent screen, such as diffuser-holographic optical elements (DHOEs), it is possible to make an AR near-eye display with a small form factor and a wide field of view. In addition, the proposed AR system compensates the chromatic aberration that occurs in PB phase lens by adopting three-layered DHOEs. The operating principle of the proposed system is covered, and its feasibility is verified with experiments and analysis.

Substance P restores normal skin architecture and reduces epidermal infiltration of sensory nerve fiber in TNCB-induced atopic dermatitis-like lesions in NC/Nga mice.

BACKGROUND: Atopic dermatitis (AD) is a chronic inflammatory skin disorder characterized by intense pruritus and eczematous lesion. Substance P (SP) is an 11-amino-acid endogenous neuropeptide that belongs to the tachykinin family and several reports recently have supported the anti-inflammatory and tissue repairing roles of SP. OBJECTIVE: In this study, we investigated whether SP can improve AD symptoms, especially the impaired skin barrier function, in 2, 4, 6-trinitrochlorobenzene (TNCB)-induced chronic dermatitis of NC/Nga mice or not. METHOD: AD-like dermatitis was induced in NC/Nga mice by repeated sensitization with TNCB for 5 weeks. The experimental group designations and topical treatments were as follows: vehicle group (AD-VE); SP group (AD-SP); and SP with NK1R antagonist CP99994 (AD-SP-A) group. Histological analysis was performed to evaluate epidermal differentiation, dermal integrity, and epidermal nerve innervation in AD-like lesions. The skin barrier functions and pruritus of NC/Nga mice were evaluated by measuring transepidermal water loss (TEWL) and scratching behavior, respectively. RESULT: Topical SP treatment resulted in significant down-regulation of Ki67 and the abnormal-type keratins (K) K6, K16, and K17, restoration of filaggrin and claudin-1, marked reduction of TEWL, and restoration of basement membrane and dermal collagen deposition, even under continuous sensitization of low dose TNCB. In addition, SP significantly reduced innervation of itch-evoking nerve fibers, gelatinase activity and nerve growth factor (NGF) expression in the epidermis but upregulated semaphorin-3A (Sema3A) expression in the epidermis, along with reduced scratching behavior in TNCB-treated NC/Nga mice. All of these effects were completely reversed by co-treatment with the NK1R antagonist CP99994. In cultured human keratinocytes, SP treatment reduced expression of TGF-α, but upregulated TGF-ß and Sema3A. CONCLUSION: Topically administered SP can restore normal skin barrier function, reduce epidermal infiltration of itch-evoking nerve fibers in the AD-like skin lesions, and alleviate scratching behavior. Thus, SP may be proposed as a potential medication for chronic dermatitis and AD.

Manifestation of atopic dermatitis-like skin in TNCB-induced NC/Nga mice is ameliorated by topical treatment of substance P, possibly through blockade of allergic inflammation.

Atopic dermatitis (AD) is a chronic inflammatory skin disorder characterized by intense pruritus and eczematous lesion. In this study, topically applied substance P (SP) significantly alleviated AD-like clinical symptoms in 2, 4, 6-trinitrochlorobenzene (TNCB)-induced dermatitis in NC/Nga mice. This effect was nullified by pretreatment of the neurokinin-1 receptor (NK-1R) antagonist CP99994. SP treatment significantly reduced the infiltration of mast cells and CD3-positive T cells as well as inflammatory cytokines, such as tumor necrosis factor-α (TNF-α) and thymic stromal lymphopoietin (TSLP), in AD-like skin lesions and decreased the levels of IgE and thymus and activation-regulated chemokine in serum. This SP-induced alleviation of allergic inflammatory responses was also confirmed as reduced activation in the axillary lymph nodes (aLN) and spleen, suggesting the systemic effect of SP on immune responses in TNCB-induced NC/Nga mice. Furthermore, SP-mediated TSLP reduction was confirmed in human keratinocyte culture under pro-inflammatory TNF-α stimulation. Taken together, these results suggest that topically administered SP may have potential as a medication for atopic dermatitis.

Clinical features of Bednar's aphthae in infants.

PURPOSE: Although Bednar's aphthae are common and regress spontaneously, these lesions may lead to feeding intolerance and are often misdiagnosed, rendering examinations useless. This study sheds new light on the clinical features of Bednar's aphthae. METHODS: Sixteen neonates and infants were newly diagnosed with Bednar's aphthae via routine health check-ups in an outpatient clinic. Medical records were retrospectively reviewed, and the following parameters were analyzed; sex, gestational age, birth weight, mode of delivery, and perinatal problems. A physical examination was carried out during the next outpatient visit to examine the healing process and check for the existence of scars or complications. RESULTS: Initial presentation included changes in feeding habits (n=10), longer feeding time, reduced intake, and increased irritability. In 6 patients, Bednar's aphthae were discovered incidentally, without prior symptoms. Feeding posture and method of feeding are important causes of Bednar's aphthae. Eleven patients were fed in a horizontal position, whereas 5 patients were fed in a semiseated position. Fifteen patients were bottle-fed, whereas 1 patient was exclusively breastfed. After correcting the feeding position, the ulcerative lesions disappeared within 1 month of diagnosis. During the follow-up period, lesions did not recur in any of the patients. CONCLUSION: This study suggests that Bednar's aphthae are caused by mechanical pressure. A diagnosis of Bednar's aphthae should be considered when lesions are found on the palate of infants and when symptoms seem to be feeding related. Proper education of parents can both treat Bednar's aphthae and easily prevent its recurrence.

Adsorption characteristics of diclofenac and sulfamethoxazole to graphene oxide in aqueous solution.

The adsorptive properties of graphene oxide (GO) were characterized, and the binding energies of diclofenac (DCF) and sulfamethoxazole (SMX) on GO adsorption were predicted using molecular modeling. The adsorption behaviors of DCF and SMX were investigated in terms of GO dosage, contact time, and pH. Additionally, the effects of sonication on GO adsorption were examined. GO adsorption involves "oxygen-containing functional groups" (OCFGs) such as COOH, which exhibit negative charges over a wide range of pH values (pH 3-11). DCF (-18.8 kcal mol(-1)) had a more favorable binding energy on the GO surface than SMX (-15.9 kcal mol(-1)). Both DCF and SMX were removed from solution (adsorbed to GO), up to 35% and 12%, respectively, within 6h, and an increase in GO dosage enhanced the removal of DCF. Electrostatic repulsion occurred between dissociated DCF/SMX and the more negatively charged GO at basic pH (>pKa). The sonication of GO significantly improved the removal of DCF (75%) and SMX (30%) due to dispersion of exfoliated GO particles and the reduction of OCFGs on the GO surface. Both DCF and SMX in the adsorption isotherm were explained well by the Freundlich model. The results of this study can be used to maximize the adsorption capacities of micropollutants using GO in water treatment processes.

Effect of substance P on recovery from laser-induced retinal degeneration.

Retinal degeneration is caused by neovascularization and persistent inflammation in the retinal pigment epithelium (RPE) and choroid, and causes serious eye disease including age-related macular degeneration (AMD). Thus, inhibiting inflammation and neovascularization may be a primary approach to protect the retina from degeneration. The purpose of this study was to determine whether substance P (SP), which can suppress inflammation and mobilize stem cells, can protect the RPE from degeneration. The effect of SP was evaluated by analyzing systemic inflammation, cell survival, and neovascularization within the argon laser-injured retina of mice. At 1 week postinjury, the SP-treated group had lower tumor necrosis factor-alpha and higher interleukin-10 serum concentrations, and a more intact retinal structure compared to the vehicle-treated group. In mice administered SP repeatedly for 4 weeks, the retinal structure appeared normal and showed sparse neovascularization, whereas the vehicle-treated group showed severe retinal destruction and dense neovascularization. Moreover, the efficacy of SP was identical to that of mesenchymal stem cells that were transplanted into the vitreous after retinal injury. This study highlights the potential for the endogenous neuropeptide SP as a treatment for retinal damage to prevent conditions such as AMD.