The Effect of Botulinum Toxin A on the NADPH Oxidase System and Ischemia-Reperfusion Injury.

BACKGROUND: Despite the increasing popularity of various materials for ischemia-reperfusion (I/R) injury mitigation, research on botulinum toxin type A (BoNTA) remains limited. This study assesses BoNTA's efficacy in protecting flaps from I/R injury by inhibiting the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase system and reducing reactive oxygen species (ROS) production. METHODS: Seventy-six Sprague-Dawley rats were studied. We examined the effects of BoNTA on superoxide production in four rats using a lucigenin-enhanced chemiluminescence assay (LECL). Another group of 60 rats had their superficial inferior epigastric artery (SIEA) flaps treated with either BoNTA or saline and clamped for 0, 1, and 4 hours before reperfusion. Flap survival and histological outcomes were assessed five days post-operation. ROS production in SIEA flaps and femoral vessels was analyzed in 12 additional rats, post-I/R injury. RESULTS: The LECL results showed that the BoNTA group had significantly lower superoxide production compared to controls, with notable reductions at 4 hours. While no significant differences were noted at the 0 and 1-hour marks, the 4-hour mark showed significant protective effects in BoNTA-treated groups. The survival rate was 90% for BoNTA-treated rats versus 60% for controls ( P = 0.028). Significant reductions in ROS were also observed in the 4-hour I/R group. CONCLUSIONS: BoNTA effectively protects against I/R injury by inhibiting the NADPH oxidase system and reducing ROS levels. These results support further investigation into the specific mechanisms of NADPH oxidase inhibition by BoNTA and its potential clinical applications, given its safety profile. CLINICAL RELEVANCE STATEMENT: The findings from the present study are expected to provide a basis for clinical studies regarding this use of BoNTA.

Customized Reconstruction of Lower Eyelid Defects.

BACKGROUND: A lower eyelid defect is a loss of skin, muscle, and underlying structures that can occur due to trauma, malignant or benign tumors, burns, or other causes. The conventional surgical treatment of lower lid defects has several limitations, including visible scarring, narrowing of the eye, and ectropion. Here, we combined the use of a customized mid-face lift with a free mucochondral graft to overcome the disadvantages of existing methods. METHODS: Forty patients underwent reconstructive surgery using a customized mid-face lift with or without a free mucochondral graft for a lower lid defect between April 2013 and October 2020. Patients were discharged shortly after surgery and were expected to visit the outpatient clinic periodically for 12 months. RESULTS: The causes of lower eyelid defects were malignancy, trauma, foreign body granuloma, and other causes. Four patients reported complications, including 2 cases of chemosis, 1 case of a hematoma, and 1 case of corneal abrasion, who reportedly performed well after 2 weeks of conservative therapy. No patient required revision during the average follow-up period. CONCLUSIONS: Customized reconstruction demonstrated a better aesthetic reconstruction of the lower eyelid. This method represents a good option for reconstructing lower lid defects.

Introduction of Deep Learning-Based Infrared Image Analysis to Marginal Reflex Distance1 Measurement Method to Simultaneously Capture Images and Compute Results: Clinical Validation Study.

Marginal reflex distance1 (MRD1) is a crucial clinical tool used to evaluate the position of the eyelid margin in relation to the cornea. Traditionally, this assessment has been conducted manually by plastic surgeons, ophthalmologists, or trained technicians. However, with the advancements in artificial intelligence (AI) technology, there is a growing interest in the development of automated systems capable of accurately measuring MRD1. In this context, we introduce novel MRD1 measurement methods based on deep learning algorithms that can simultaneously capture images and compute the results. This prospective observational study involved 154 eyes of 77 patients aged over 18 years who visited Chungnam National University Hospital between 1 January 2023 and 29 July 2023. We collected four different MRD1 datasets from patients using three distinct measurement methods, each tailored to the individual patient. The mean MRD1 values, measured through the manual method using a penlight, the deep learning method, ImageJ analysis from RGB eye images, and ImageJ analysis from IR eye images in 56 eyes of 28 patients, were 2.64 ± 1.04 mm, 2.85 ± 1.07 mm, 2.78 ± 1.08 mm, and 3.07 ± 0.95 mm, respectively. Notably, the strongest agreement was observed between MRD1_deep learning (DL) and MRD1_IR (0.822, p < 0.01). In a Bland-Altman plot, the smallest difference was observed between MRD1_DL and MRD1_IR ImageJ, with a mean difference of 0.0611 and ΔLOA (limits of agreement) of 2.5162, which was the smallest among all of the groups. In conclusion, this novel MRD1 measurement method, based on an IR camera and deep learning, demonstrates statistical significance and can be readily applied in clinical settings.

Aberration Theory of a Flat, Aplanatic Metalens Doublet and the Design of a Meta-Microscope Objective Lens.

A theoretical approach for reducing multiple monochromatic aberrations using a flat metalens doublet is proposed and verified through ray tracing simulations. The theoretical relation between the Abbe sine condition and the generalized Snell's law is revealed in the doublet system. Starting from the Abbe aplanat design, minimization conditions of astigmatism and field curvature are derived. Based on the theory, a metalens doublet is semi-analytically optimized as a compact, practical-level meta-microscope objective lens working for a target wavelength. The proposed approach also reveals how to reduce lateral chromatism for an additional wavelength. The design degree of freedom and fundamental limits of the system are both rigorously analyzed in theory and verified through ray tracing simulations. It is expected that the proposed method will provide unprecedented practical opportunities for the design of advanced compact microscopic imaging or sensing systems.

Smartphone-Based LiDAR Application for Easy and Accurate Wound Size Measurement.

The accurate assessment of wound size is a critical step in advanced wound care management. This study aims to introduce and validate a Light Detection and Ranging (LiDAR) technique for measuring wound size. Twenty-eight wounds treated from December 2022 to April 2023 at the Chungnam National University Hospital were analyzed. All the wounds were measured using three techniques: conventional ruler methods, the LiDAR technique, and ImageJ analysis. Correlation analysis, linear regression, and Bland-Altman plot analysis were performed to validate the accuracy of the novel method. The measurement results (mean ± standard deviation) obtained using the ruler method, LiDAR technique, and ImageJ analysis were 112.99 ± 110.07 cm2, 73.59 ± 72.97 cm2, and 74.29 ± 72.15 cm2, respectively. The Pearson correlation coefficient was higher for the LiDAR application (0.995) than for the conventional ruler methods (mean difference, -5.0000 cm2), as was the degree of agreement (mean difference, 38.6933 cm2). Wound size measurement using LiDAR is a simple and reliable method that will enable practitioners to conveniently assess wounds with a flattened and irregular shape with higher accuracy. However, non-flattened wounds cannot be assessed owing to the technical limitations of LiDAR.

The Effect of Botulinum Toxin A on NADPH oxidase system and Ischemia Reperfusion Injury.

BACKGROUND: While studies aimed at overcoming ischemia-reperfusion (IR) injury using various materials are becoming popular, studies using botulinum toxin type A (BoNTA) are still limited. This study tested the hypotheses that BoNTA can protect flaps from IR injury by inhibiting the NADPH oxidase system and suppressing ROS (reactive oxygen species) production. MATERIAL AND METHODS: The subjects were Sprague-Dawley rats (n = 76). In 4 rats, the effects of different dose of BoNTA on superoxide production was evaluated through lucigenin enhanced chemiluminescence assay (LECL) using SD rats' thoracic aorta ring. In 60 SD rats, The BoNTA and normal saline-pretreated superficial inferior epigastric artery (SIEA) flaps were clamped for 0, 1, and 4 hours, and reperfused. On the 5th day after the opeartion, well-maintained flaps were grossly inspected, survival rates were analyzed, and histological analysis was also performed. In 12 rats, after making IR injury through the same model, SIEA flap segments and femoral vessels were obtained, and ROS production was evaluated through LECL and dihydroethidium (DHE) staining. RESULTS: In LECL, the experimental group produced a smaller amount of superoxide than the control group through NADPH oxidase inhibition (p < .05). There was no significant difference between the experimental and control group in the 0, and 1 hour IR groups, but the experimental group (90%) showed a higher survival rate than the control group (60%) in the 4 hours IR group (p = .028). In the measurement of ROS production through LECL and DHE staining, there was no significant difference in the 0, and 1 hour IR groups, but a significant difference was shown in the 4 hours IR group in both the SIEA flaps and femoral vessels (p < .05). SUMMARY: This study verified hypothesis that BoNTA can protect flaps from IR injury by inhibiting the NADPH oxidase system and suppressing ROS production. Based on this research model, future research should be expanded into studies on subtypes or subunits of NADPH oxidase, and the findings from the present study are expected to contribute and lead to clinical studies on BoNTA, which has already been proven to be clinically safe.

Mandible Angle Resection with the Retroauricular Approach.

Square-shaped and large moon-shaped faces are commonly observed in Asians, and the contour of the mandible is associated with the shape of the lower part of the face. Mandible contouring surgery is performed to create a softer impression for East Asians. Currently, most surgeries are performed using an intraoral approach. External approaches have not been cosmetically attempted because of possible damage to the facial nerve and visible scarring and have been limited to mandible bone fracture reduction. This study included 42 patients who underwent mandibular angle reduction via classical intraoral incision and retroauricular incision between April 2019 and October 2021. Clinical outcomes were assessed using the Global Aesthetic Improvement Scale and Visual Analog Scale. Surgery was successful in all cases, with no significant complications. An appropriate mandibular contour was achieved postoperatively. All patients were satisfied with the outcome. Some patients experienced short-term complications, such as hematoma and wound disruption of the skin above the incision line. However, these improved within 3 weeks, and no serious long-term complications were observed. Mandible angle resection with the retroauricular approach is a promising alternative for patients, allowing speedy recovery and the resumption of routine daily life.

Reconstruction of complex knee wounds with a distally based gracilis flap and gastrocnemius myocutaneous flap: A case report.

A gastrocnemius muscle flap is a versatile option for covering the proximal one-third of the lower leg and around the knee. On the other hand, it is of limited use in patients with short gastrocnemius muscle or insufficient volume. The authors present a case in which a knee soft tissue defect occurred in a very thin patient and was reconstructed using a gastrocnemius myocutaneous flap and a distally based gracilis flap as a supplementary flap.

Designing with relaxed skin tension line in perforator-based island flap for sacral sore reconstruction: A STROBE-compliant observational study.

Many various types of operative techniques have been performed used to treat make-up for sacral defects. Perforator-based flaps with flap transposition, but achieving an optimal flap design and tension-free flap closure without skeletonizing the perforator requires a great deal of clinical experience. In this study, we demonstrate perforator selection based on considerations of the relaxed skin tension line (RSTL), which has proven to be a suitable method of achieving an efficient flap design that enables primary closure. Twenty-five perforator-based flap procedures were performed on 25 patients at a single institution from February 2018 to January 2021. The medical records of patients were retrospectively reviewed. Twenty-three flaps survived completely. Two flaps developed partial tip necrosis but recovered after secondary healing, and 1 patient developed temporary congestion, which resolved spontaneously. No recipient or donor site recurrence or dehiscence was identified during follow-up. We report our clinical experiences of perforator-based flap use in the sacral region. When selecting an appropriate perforating vessel, 2 important points should be considered, that is, a flap long axis parallel to RSTLs and defect shape. According to the method presented in this paper, perforator-based flaps can be transposed safely and easily with few complications and serve as useful practice models to cover sacral defects.

Design of highly perceptible dual-resonance all-dielectric metasurface colorimetric sensor via deep neural networks.

Colorimetric sensing, which provides effective detection of bio-molecular signals with one's naked eye, is an exceptionally promising sensing technique in that it enables convenient detection and simplification of entire sensing system. Though colorimetric sensors based on all-dielectric nanostructures have potential to exhibit distinct color variations enabling manageable detection due to their trivial intrinsic loss, there is crucial limitation that the sensitivity to environmental changes lags behind their plasmonic counterparts because of relatively small region of near field-analyte interaction of the dielectric Mie-type resonator. To overcome this challenge, we proposed all-dielectric metasurface colorimetric sensor which exhibits dual-resonance in the visible region. Thereafter, we confirmed with simulation that, in the elaborately designed dual-Lorentzian-type spectra, highly perceptible variations of structural color were manifested even in minute change of peripheral refractive index. In addition to verifying physical effectiveness of the superior colorimetric sensing performance appearing in the dual-resonance type sensor, by combining advanced optimization technique utilizing deep neural networks, we attempted to maximize sensing performance while obtaining dramatic improvement of design efficiency. Through well-trained deep neural network that accurately simulates the input target spectrum, we numerically verified that designed colorimetric sensor shows a remarkable sensing resolution distinguishable up to change of refractive index of 0.0086.

Aesthetic Removal of Foreign Body Granulomas of Forehead Via Pretrichial Approach.

ABSTRACT: In the field of plastic surgery, various filler types have been developed, which are widely used for cosmetic or reconstruction purposes. However, unregulated substances often injected by unlicensed practitioners may cause difficult-to-treat side effects, such as foreign body granulomas. Since the forehead is an exposed area and the lesions are likely extensive, complete surgical removal with inconspicuous scar can be difficult. In addition, pharmacological treatments, such as steroids, have only a temporary effect. The authors report successful cases of foreign body removal combined with subcutaneous forehead lift via a pretrichial approach for cosmetic satisfaction.Ten patients who had received illegal filler injections that resulted in chronic granulomas on the forehead were studied. The granulomas were confirmed using sonography, and simultaneous foreign body removal and subcutaneous forehead lifts using pretrichial incisions were planned. For the surgical method, the forehead flap was carefully elevated to a uniform thickness in the subcutaneous plane via a pretrichial incision, and the foreign body was removed, paying attention to the forehead contour and nerve damage; excess skin was excised from the top of the flap to tighten the remaining skin on the forehead.None of the patients developed complications, such as skin necrosis, infection, hematoma, or wound dehiscence, during the follow-up period. The functional and aesthetic outcomes were satisfactory in all the patients.The subcutaneous forehead lift via a pretrichial incision seems to facilitate foreign body removal and improve the forehead deformity by tightening the remaining skin.

Tauroursodeoxycholic Acid Decreases Keloid Formation by Reducing Endoplasmic Reticulum Stress as Implicated in the Pathogenesis of Keloid.

Keloids are a common form of pathologic wound healing and are characterized by an excessive production of extracellular matrix. This study examined the major contributing mechanism of human keloid pathogenesis using transcriptomic analysis. We identified the upregulation of mitochondrial oxidative stress response, protein processing in the endoplasmic reticulum, and TGF-ß signaling in human keloid tissue samples compared to controls, based on ingenuity pathway and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. Electron microscopic examinations revealed an increased number of dysmorphic mitochondria and expanded endoplasmic reticulum (ER) in human keloid tissue samples than that in controls. Western blot analysis performed using human tissues suggested noticeably higher ER stress signaling in keloids than in normal tissues. Treatment with tauroursodeoxycholic acid (TUDCA), an ER stress inhibitor, significantly decreased scar formation in rabbit models, compared to normal saline and steroid injections. In summary, our findings demonstrate the contributions of mitochondrial dysfunction and dysregulated ER stress signaling in human keloid formation and the potential of TUDCA in the treatment of keloids.

Dielectric Metalens: Properties and Three-Dimensional Imaging Applications.

Recently, optical dielectric metasurfaces, ultrathin optical skins with densely arranged dielectric nanoantennas, have arisen as next-generation technologies with merits for miniaturization and functional improvement of conventional optical components. In particular, dielectric metalenses capable of optical focusing and imaging have attracted enormous attention from academic and industrial communities of optics. They can offer cutting-edge lensing functions owing to arbitrary wavefront encoding, polarization tunability, high efficiency, large diffraction angle, strong dispersion, and novel ultracompact integration methods. Based on the properties, dielectric metalenses have been applied to numerous three-dimensional imaging applications including wearable augmented or virtual reality displays with depth information, and optical sensing of three-dimensional position of object and various light properties. In this paper, we introduce the properties of optical dielectric metalenses, and review the working principles and recent advances in three-dimensional imaging applications based on them. The authors envision that the dielectric metalens and metasurface technologies could make breakthroughs for a wide range of compact optical systems for three-dimensional display and sensing.

Cadaveric study of deep temporal fascia for autologous rhinoplasty grafts: Dimensions of the temporal compartment in Asians.

BACKGROUND: Due to the anatomical complexity of the deep temporal fascia (DTF), practical guidelines for its safe harvest are lacking. However, since the upper temporal compartment (UTC) contains no vital structures, it may provide safe access for DTF harvest. This study aimed to identify the anatomical structures of the temporal compartment in Asian cadavers and to measure their dimensions to enable safe DTF harvest. METHODS: The anatomical structures surrounding the temporal compartment were identified in 27 hemifaces from 15 Korean cadavers. After dissection, digital images were acquired and craniometric landmarks were placed upon them to identify the boundaries of the temporal compartment. The horizontal and vertical lengths of the temporal compartment were measured and their surface areas were computationally assessed. Subsequently, differences in the results by sex were evaluated. RESULTS: The five-layer anatomical structure of the UTC was clearly visualized. The UTC was bounded by the temporal septa superiorly and inferiorly, the innominate fascia laterally, and the DTF medially. No vital structures were present within the UTC. The vertical and horizontal lengths of the UTC were 6.41±0.67 cm and 10.44±0.83 cm, respectively, and the surface area of the UTC was 48.52±5.65 cm2. No statistically significant differences were observed in any dimensions between male and female patients. CONCLUSIONS: During rhinoplasty, DTF can be harvested as an autologous graft material from the UTC. An anatomical understanding of the UTC will aid in the safe and simple harvest of a sufficient amount of DTF.

In Vitro and in Vivo Biocompatibility and Degradability Evaluation of Modified Polydioxanone Plate.

BACKGROUND: Polydioxanone (PDS) has been widely used in the medical field over the past 30 years. In the 2000s, PDS plate began to be used for rhinoplasty and septoplasty. However, in Asia PDS plates are not widely used due to lack of awareness and high prices. The authors devised a method of producing a modified PDS (m-PDS; Rhinoblock Material & Design Co., Gyeonggi-do, Sothh Korea) at low cost, and compared the biocompatibilities and degradabilities of plates produced with m-PDS and commercial PDS plates (Ethicon, Somerville, NJ) in vivo and in vitro. METHODS: The melting point and decomposition rate of m-PDS were determined by differential scanning calorimetry and thermogravimetric analysis and its tensile strength was also measured. Implants (1 cm × 1 cm × 0.15 mm sized) were inserted subcutaneously into mice and harvested en bloc 2, 5, 10, 15, or 25 weeks later. Tissues were stained with hematoxylin and eosin or Masson's trichrome to evaluate inflammation, extracellular matrix deposition, and vascularization, and plate degradability was also assessed. RESULTS: No significant difference was observed between the thermal analysis and tensile test results of m-PDS and PDS plates. m-PDS started to degrade in vivo from around 10 weeks, and commercial PDS plates from around 15 weeks. After 25 weeks in vivo, both products were completely degraded and not observed in tissue slides. Histologic analysis of excised specimens showed m-PDS and PDS were similar in terms of inflammation, extracellular matrix deposition, and vascularization. CONCLUSION: In vivo and in vitro experiments detected no significant difference between the biocompatibilities and degradabilities of modified and commercial PDS plates. The results of this study suggest that the modified PDS can be used to produce versatile, low cost, absorbable graft materials for rhinoplasty and septoplasty.

Doublet metalens design for high numerical aperture and simultaneous correction of chromatic and monochromatic aberrations.

Metalens is one of the most prominent applications among metasurfaces since it gives possibilities to replace the conventional lenses for compactness and multi-functionalities. Recently, many studies have been demonstrated to overcome the aberrations of the metalenses for high performance practical applications. Previous studies have used the methods that control the dispersion of meta-atoms for correcting chromatic aberrations and use doublet platform for correcting monochromatic aberrations. Despite these studies and the large demands for simultaneous correction of the aberrations in high numerical aperture metalens, the simultaneous correction has not been demonstrated yet. In this paper, we report the doublet metalens design with high numerical aperture which corrects longitudinal chromatic aberration and four monochromatic aberrations including spherical aberration, coma, astigmatism, and field curvature simultaneously for the three primary visible colors. Based on the novel doublet platform, the multi-wavelength targeted correction lens and geometric phase lens with color filtering functionality are utilized. Our doublet metalens has numerical apertures of 0.33, 0.38, and 0.47 for 445 nm, 532 nm, and 660 nm, respectively. The back focal length of our doublet metalens remains nearly 360 µm for target wavelengths and incident angles up to 30 degrees.

Full-Color-Tunable Nanophotonic Device Using Electrochromic Tungsten Trioxide Thin Film.

Color generation based on strategically designed plasmonic nanostructures is a promising approach for display applications with unprecedented high-resolution. However, it is disadvantageous in that the optical response is fixed once the structure is determined. Therefore, obtaining high modulation depth with reversible optical properties while maintaining its fixed nanostructure is a great challenge in nanophotonics. In this work, dynamic color tuning and switching using tungsten trioxide (WO3), a representative electrochromic material, are demonstrated with reflection-type and transmission-type optical devices. Thin WO3 films incorporated in simple stacked configurations undergo dynamic color change by the adjustment of their dielectric constant through the electrochromic principle. A large resonance wavelength shift up to 107 nm under an electrochemical bias of 3.2 V could be achieved by the reflection-type device. For the transmission-type device, on/off switchable color pixels with improved purity are demonstrated of which transmittance is modulated by up to 4.04:1.

Reconfigurable all-dielectric Fano metasurfaces for strong full-space intensity modulation of visible light.

Dynamically reconfigurable nanoscale tuning of visible light properties is one of the ultimate goals both in the academic field of nanophotonics and the optics industry demanding compact and high-resolution display devices. Among various efforts incorporating actively reconfigurable optical materials into metamaterial structures, phase-change materials have been in the spotlight owing to their optical tunability in wide spectral regions including the visible spectrum. However, reconfigurable modulation of visible light intensity has been limited with small modulation depth, reflective schemes, and a lack of profound theoretical background for universal design rules. Here, all-dielectric phase-change Fano metasurface gratings are demonstrated for strong dynamic full-space (reflection and transmission) modulation of visible intensities based on Fano resonances. By judicious periodic couplings between densely arranged meta-atoms containing VO2, phase-change induced thermo-optic modulation of full-space intensities is highly enhanced in the visible spectrum. By providing intuitive design rules, we envision that the proposed study would contribute to nanophotonics-enabled optoelectronics technologies for imaging and sensing.

Ultracompact meta-pixels for high colour depth generation using a bi-layered hybrid metasurface.

Nano-structural colour pixels have attracted much attention as promising solutions for compact display devices. However, it is difficult to miniaturize and integrate conventional transmissive colour filtering components for high resolution pixels within subwavelength scale without sacrificing colour depth. Here, we propose a novel colour pixel structure using bi-layered hybrid metasurfaces that are composed of aluminum nanograting and amorphous silicon nanorod layers. The independent high-contrast control of resonance intensity and spectral position is achieved by anisotropic Mie resonances and cavity effect between stacked two metasurfaces. Moreover, the proposed structures permit the wide colour gamut through the novel physical principles. In addition, a meta-pixel which can provide gradual tuning of colour is demonstrated to obtain high colour depth. The proposed structures are expected to be fruitful for the development of next generation display and imaging systems.