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Background Hypothenar free flaps (HTFFs) have been widely used for reconstructing palmar defects. Although previous anatomical and clinical studies of HTFF have been conducted, this technique still has some limitations. In this study, we describe some tips for large flap design that allows for easy harvesting of HTFFs with minimal donor site morbidity. Methods A total of 14 HTFF for hand defect reconstruction were recorded. The oblique flap was designed in the proximal HT area following relaxed skin tension line along the axis between fourth web space and 10 mm ulnar side of pisiform. A flap pedicle includes one or two perforators with ulnar digital artery and HT branch of basilic vein. In addition, innervated HTFF can be harvested with a branch of ulnar digital nerve. Electronic medical records were reviewed to obtain data on patients' information, operative details, and follow-up period. In addition, surgical outcome score was obtained from the patient, up to 10 points, at the last follow-up. Results Mean harvest time was 46 minutes, and two perforators were included in 10 cases. The mean flap area was 10.84 cm2. There were no problems such as donor site depression, scar contracture, keloids, wound dehiscence, numbness or neuroma pain at donor sites, and hypersensitivity or cold intolerance at flap site, either functionally or aesthetically. Conclusion Palmar defect reconstruction is challenging for hand surgeons. However, large HTFF can be harvested without complications using the oblique axis HTFF technique. We believe our surgical tips increase utility of HTFF for palmar defect reconstruction.

The experimental data obtained in a wave flume were analyzed using machine learning techniques to establish a model that predicts the input wave height of the wavemaker based on the waves that have experienced wave shoaling and to verify the performance of the established model. For this purpose, artificial neural network (NN), the most representative machine learning technique, and Gaussian process regression (GPR), one of the non-parametric regression analysis methods, were applied respectively. Then, the predictive performance of the two models was compared. The analysis was performed independently for the case of using all the data at once and for the case by classifying the data with a criterion related to the occurrence of wave breaking. When the data were not classified, the error between the input wave height at the wavemaker and the measured value was relatively large for both the NN and GPR models. On the other hand, if the data were divided into non-breaking and breaking conditions, the accuracy of predicting the input wave height was greatly improved. Among the two models, the overall performance of the GPR model was better than that of the NN model.

Indium gallium nitride (InGaN)-based micro-LEDs (μLEDs) are suitable for meeting ever-increasing demands for high-performance displays owing to their high efficiency, brightness and stability

Charge ordering (CO), periodic modulation of electron density and lattice distortion, has been the fundamental subject in condensed matter physics, as well as a potential platform to induce novel functional properties. The charge-ordered phase is known to occur in a doped system of high d-electron occupancy but not of low occupancy. Here, we report that the charge-ordered phase is realized in electron-doped (100) SrTiO3 epitaxial thin films that have the lowest d-electron occupancy i.e., d1-d0. Theoretical calculation predicts the presence of a metastable CO state at the bulk state of electron-doped SrTiO3. Atomic scale analysis reveals that (100) surface distortion prefers the electron-lattice coupling for the charge-ordered state and triggers the stabilization for the CO phase from correlated metal, which extends up to six unit cells from the top surface to the interior. Our approach will provide an insight on the way to stabilize a new phase of matter that extends CO phase to the lowest electron occupancy, covering a whole range of 3d transition metal oxide.

Purpose: We investigated what changes occurred at single hand surgery center during the coronavirus disease 2019 (COVID-19) pandemic in Daegu, Korea using patient data of 4 years (2018–2021).Methods: This is a single-center retrospective study of patients visiting our center during the COVID-19 pandemic (January 22 to May 6, 2020) in comparison to the most recent 4 years from 2018 to 2021. Service volumes (SVs) including the number of in/outpatients, emergency room, elective, and emergency surgeries were analyzed. The demographics, injury mechanism, and place of injury of hand trauma were analyzed in patients seen during the peak period of COVID-19 (February 24 to March 9, 2020) at W Hospital.Results: SVs were significantly reduced in 2020 as compared with other years. The SVs except for the number of emergency surgeries have recovered after 2 months from the first confirmed case of COVID-19 in Daegu, Korea. At the peak period, the effect of COVID-19 was weak on emergency room-related SVs. In addition, a daily number of in/outpatients and elective surgeries had a statistically significant negative correlation with the number of COVID-19 confirmed (p

Physical experiments were conducted to establish an empirical formula that predicts the wave force on the upside of the pavement behind crown wall of rubble mound seawall due to wave overtopping as well as the uplift force on the downside of the pavement. The experiments were performed by different conditions of the parapet, water depth, relative freeboard, and thickness of the armour layer. Then, the wave force on the upside and downside of the pavement behind the crown wall was analyzed. The parameters that affect the wave overtopping force and the uplift force were identified and empirical formulae were suggested for evaluating the forces on the pavement.

An epidermoid cyst is a slow-growing benign neoplasm that commonly occurs in the hand. Herein, we report a rare case of an epidermoid cyst with focal neuropathy in the left ring finger of a 38-year-old woman. Preoperatively, the patient complained of erythema, swelling, and paresthesia on her fingertips. On ultrasonography and magnetic resonance imaging, ulnar digital nerve thickening and inflammation around the nerve were observed, and a neurogenic tumor-like schwannoma was expected. An excisional biopsy with neurectomy of the involved sensory branch of the ulnar digital nerve was performed under brachial plexus block. During the operation, there is such an uncommon morphology, yellowish debris under the epineurium of the ulnar digital nerve sensory branch was involved with the epidermoid cyst and seemed to be propagating along the sensory branch from the skin surface. After the operation, the paresthesia and swelling resolved. Over the 6-month follow-up in the outpatient clinic, no complications and recurrences occurred. Thus, we reported a rare intraneural epidermoid cyst (occurred along the digital nerve) in the finger, and we believe that considering the anatomical characteristics and the surrounding structures is important during mass excision.

Purpose: This study evaluated the functional and aesthetic outcomes of a wide-second dorsal metacarpal artery perforator flap for reconstruction of the first web space of the hand. This flap sets the proximal edge of the extensor retinaculum as the distal limit.Methods: We measured the preoperative and postoperative angles of the first web space and assessed the quality of the donor site scar in eight patients.Results: The average flap size was 5.5 × 2.8 cm (range, 5.0 × 1.5 cm to 5.0 × 6.0 cm), and all flaps survived completely. The mean postoperative angle was 53°. The mean Vancouver Scar Scale score of the donor site was 4 points, and the patients had near-normal thickness and vascularity values. There was no distortion of the scar, and patients were satisfied with the scar appearance of the donor site.Conclusion: The wide-second dorsal metacarpal artery perforator flap is a useful technique to reconstruct large defects of the first web space. It is easy to raise, thin, and pliable, and has excellent color and tissue matching.

Funding: This work was supported by National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. NRF-2020R1A2C2101735), Creative Materials Discovery Program (NRF-2019M3D1A1078299), the Samsung Research Funding & Incubation Center of Samsung Electronics under Project Number SRFC-MA1702-01, and the KENTECH Research Grant (KRG2022-01-019). D.I.B. acknowledges the financial support from Russian Foundation for Basic Research under Grant No. 19-29-03051MK. The first-principle calculations were performed using the facilities of the Joint Supercomputer Center of the Russian Academy of Sciences (JSCC RAS). J.L. acknowledges the support of an NRF grant funded by the Korean government (NRF-2018R1A2B6004394). J.T.S.I. thanks the EPSRC for support on emergent nanomaterials through Grant EP/R023522/1. Y.X. and S.H.O. acknowledge the support from Advanced Facility Center for Quantum Technology. Exsolution of excess transition metal cations from a non-stoichiometric perovskite oxide has sparked interest as a facile route for the formation of stable nanoparticles on the oxide surface. However, the atomic-scale mechanism of this nanoparticle formation remains largely unknown. The present in situ scanning transmission electron microscopy combined with density functional theory calculation revealed that the anti-phase boundaries (APBs) characterized by the a/2 < 011> type lattice displacement accommodate the excess B-site cation (Ni) through the edge-sharing of BO6 octahedra in a non-stoichiometric ABO3 perovskite oxide (La0.2Sr0.7Ni0.1Ti0.9O3-δ) and provide the fast diffusion pathways for nanoparticle formation by exsolution. Moreover, the APBs further promote the outward diffusion of the excess Ni toward the surface as the segregation energy of Ni is lower at the APB/surface intersection. The formation of nanoparticles occurs through the two-step crystallization mechanism, i.e., the nucleation of an amorphous phase followed by crystallization, and via reactive wetting on the oxide support, which facilitates the formation of a stable triple junction and coherent interface, leading to the distinct socketing of nanoparticles to the oxide support. The atomic-scale mechanism unveiled in this study can provide insights into the design of highly stable nanostructures. Publisher PDF

The extensive utilization of electronic health records (EHRs) and the growth of enormous open biomedical datasets has readied the area for applications of computational and machine learning techniques to reveal fundamental patterns. This study’s goal is to develop a medical treatment recommendation system using Korean EHRs along with the Markov decision process (MDP). The sharing of EHRs by the National Health Insurance Sharing Service (NHISS) of Korea has made it possible to analyze Koreans’ medical data which include treatments, prescriptions, and medical check-up. After considering the merits and effectiveness of such data, we analyzed patients’ medical information and recommended optimal pharmaceutical prescriptions for diabetes, which is known to be the most burdensome disease for Koreans. We also proposed an MDP-based treatment recommendation system for diabetic patients to help doctors when prescribing diabetes medications. To build the model, we used the 11-year Korean NHISS database. To overcome the challenge of designing an MDP model, we carefully designed the states, actions, reward functions, and transition probability matrices, which were chosen to balance the tradeoffs between reality and the curse of dimensionality issues.

Cybersecurity is a growing concern in today’s interconnected world. Traditional cybersecurity approaches, such as signature-based detection and rule-based firewalls, are often limited in their ability to effectively respond to evolving and sophisticated cyber threats. Reinforcement learning (RL) has shown great potential in solving complex decision-making problems in various domains, including cybersecurity. However, there are significant challenges to overcome, such as the lack of sufficient training data and the difficulty of modeling complex and dynamic attack scenarios hindering researchers’ ability to address real-world challenges and advance the state of the art in RL cyber applications. In this work, we applied a deep RL (DRL) framework in adversarial cyber-attack simulation to enhance cybersecurity. Our framework uses an agent-based model to continuously learn from and adapt to the dynamic and uncertain environment of network security. The agent decides on the optimal attack actions to take based on the state of the network and the rewards it receives for its decisions. Our experiments on synthetic network security show that the DRL approach outperforms existing methods in terms of learning optimal attack actions. Our framework represents a promising step towards the development of more effective and dynamic cybersecurity solutions.

Two advanced, automated crystal orientation mapping techniques suited for nanocrystalline materials—precession electron diffraction (PED) in transmission electron microscopy (TEM) and on-axis transmission Kikuchi diffraction (TKD) in scanning electron microscopy (SEM)—are evaluated by comparing the orientation maps obtained from the identical location on a 30 nm-thick nanocrystalline tungsten (W) thin film. A side-by-side comparison of the orientation maps directly showed that the large-scale orientation features are almost identical. However, there are differences in the fine details, which arise from the fundamentally different nature of the spot pattern and Kikuchi line pattern in terms of the excitation volume and the angular resolution. While TEM-PED is more reliable to characterize grains oriented along low-index zone axes, the high angular resolution of SEM-TKD allows the detection of small misorientation between grains and thus yields better quantification and statistical analysis of grain orientation. Given that both TEM-PED and SEM-TKD orientation mapping techniques are complementary tools for nanocrystalline materials, one can be favorably selected depending on the requirements of the analysis, as they have competitive performance in terms of angular resolution and texture quantification.

Vitiligo is a relatively common, acquired hypopigmentary disorder caused by the loss of epidermal melanocytes. It is characterized by asymptomatic, well-circumscribed round to oval-shaped whitish patches that vary in size. Depending on various clinical features, vitiligo is classified into several types, that is, non-segmental, segmental, and undetermined/unclassified vitiligo. The uniform classification of vitiligo is very important in predicting its clinical course and prognosis and communication among researchers. In particular, segmental vitiligo is a highly distinctive subtype of vitiligo considering its clinical features and prognosis. It usually has an onset early in life and spreads rapidly within the affected area limited to one segment of the integument. Signs of vitiligo activity such as Koebnerʼs phenomenon, trichrome vitiligo, inflammatory vitiligo, and confetti-like lesions give useful information to start treatments to block the progression of the disease. Lastly, other hypopigmentary disorders should be distinguished from vitiligo to make the correct diagnosis and prescribe the right treatment. In this report, I review the clinical features of vitiligo, various subtypes according to classification, and the importance for differential diagnosis of hypopigmentary disorders from vitiligo.

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The reliability of Ge–Sb–Te phase-change memory (PCM) devices has been limited by failure due to void formation and this still remains one of the critical issues affecting their use in storage-class memory applications. To directly observe the void formation processes in real-time, we implemented in situ switching of PCM devices by applying set and reset voltage pulses to a Ge2Sb2Te5 (GST) cell inside a transmission electron microscope (TEM). The in situ TEM observations directly show that a void nucleates preferentially near the TiN bottom electrode in the GST cell, where the temperature is the highest. The nucleated void grows gradually until it reaches a certain size while migrating slowly toward the positively biased electrode. The fully grown void then continues migrating toward the positively biased electrode in subsequent set pulses. The observed polarity-dependent void migration can be explained by the field-induced redistribution of the constituent elements, especially by the electromigration of under-coordinated Te− ions which have vacancies around them. When the reset pulse with the same voltage polarity is applied, the voids exhibit a slight volume shrinkage but are not completely eliminated, resulting in a reset-stuck failure. The present in situ TEM observations revealing the nucleation, growth, and polarity-dependent migration of voids will contribute to the fundamental understanding of the failure by void formation in nanoscale GST-based PCM devices and help improving the design of reliable PCM devices.

CXCL12 and its receptors, which are highly expressed in the skin, are associated with various cutaneous diseases, including androgenic alopecia. However, their expression and role during the hair cycle are unknown. This study aims to investigate the expression of CXCL12 and its receptor, CXCR4, in the vicinity of hair follicles and their effect on hair growth. CXCL12 was highly expressed in dermal fibroblasts (DFs) and its level was elevated throughout the catagen and telogen phases of the hair cycle. CXCR4 is expressed in the dermal papilla (DP) and outer root sheath (ORS). In hair organ culture, hair loss was induced by recombinant CXCL12 therapy, which delayed the telogen-to-anagen transition and decreased hair length. In contrast, the suppression of CXCL12 using a neutralizing antibody and siRNA triggered the telogen-to-anagen transition and increased hair length in hair organ culture. Neutralization of CXCR7, one of the two receptors for CXCL12, only slightly affected hair growth. However, inhibition of CXCR4, the other receptor for CXCL12, increased hair growth to a considerable extent. In addition, in hair organ culture, the conditioned medium from DFs with CXCL12 siRNA considerably increased the hair length and induced proliferation of DP and ORS cells. CXCL12, through CXCR4 activation, increased STAT3 and STAT5 phosphorylation in DP and ORS cells. In contrast, blocking CXCL12 and CXCR4 decreased the phosphorylation of STAT3 and STAT5. In summary, these findings suggest that CXCL12 inhibits hair growth via the CXCR4/STAT signaling pathway and that CXCL12/CXCR4 pathway inhibitors are a promising treatment option for hair growth.

Precision medicine is a new approach to understanding health and disease based on patient-specific data such as medical diagnoses; clinical phenotype; biologic investigations such as laboratory studies and imaging; and environmental, demographic, and lifestyle factors. The importance of machine learning techniques in healthcare has expanded quickly in the last decade owing to the rising availability of vast multi-modality data and developed computational models and algorithms. Reinforcement learning is an appealing method for developing efficient policies in various healthcare areas where the decision-making process is typically defined by a long period or a sequential process. In our research, we leverage the power of reinforcement learning and electronic health records of South Koreans to dynamically recommend treatment prescriptions, which are personalized based on patient information of hypertension. Our proposed reinforcement learning-based treatment recommendation system decides whether to use mono, dual, or triple therapy according to the state of the hypertension patients. We evaluated the performance of our personalized treatment recommendation model by lowering the occurrence of hypertension-related complications and blood pressure levels of patients who followed our model’s recommendation. With our findings, we believe that our proposed hypertension treatment recommendation model could assist doctors in prescribing appropriate antihypertensive medications.

Dislocations in single-phase concentrated random alloys, including high- entropy alloys (HEAs), repeatedly encounter pinning during glide, resulting in jerky dislocation motion. While solute-dislocation interaction is well understood in conventional alloys, the origin of individual pinning points in concentrated random alloys is a matter of debate. In this work, we investigate the origin of dislocation pinning in the CoCrFeMnNi HEA. In- situ transmission electron microscopy studies reveal wavy dislocation lines and a jagged glide motion under external loading, even though no segregation or clustering is found around Shockley partial dislocations. Atomistic simulations reproduce the jerky dislocation motion and link the repeated pinning to local fluctuations in the Peierls friction. We demonstrate that the density of high local Peierls friction is proportional to the critical stress required for dislocation glide and the dislocation mobility., Accepted version

Nacre's superior mechanical properties and failure behavior are strongly orientation-dependent due to its brick-and-mortar microstructure. In this work, the anisotropic microscopic deformation and the resulting macroscopic mechanical properties are evaluated under different loading conditions. Our in situ transmission electron microscopy deformation experiments and finite element simulations reveal that nacre possesses enhanced indentation resistance along the direction normal to the tablets through delocalization of indentation-induced deformation by taking advantage of its layered structure. In addition, nacre's ability to recover from large deformations is observed. We study the strong loading direction dependence of nacre's macroscopic mechanical properties and elucidate the underlying microscopic deformation patterns in the tablets and the soft matrix. Particularly, its performance along the transverse direction is optimized to withstand the loading conditions in nature. We show the importance of the vertical matrix for the initial stiffness and fracture toughness of the composite. These findings provide guidelines for designing nacre-inspired artificial composites with enhanced mechanical properties. STATEMENT OF SIGNIFICANCE: Nacre is widely recognized as an excellent structural model for designing bio-inspired tough and strong artificial composites. Due to its brick-and-mortar microstructure, it exhibits loading direction-dependent mechanical behavior. In this contribution, we investigate the macroscopic mechanical properties and microscopic deformation behavior of nacre under different loading conditions by means of in situ TEM deformation tests and FE simulations. It is found that effective elastic moduli and microscopic deformation strongly depend on the loading direction. The organic matrix is highly deformable. The indentation resistance along the direction normal to tablets is enhanced via deformation delocalization. Our quantitative and qualitative results provide guidelines on optimizing the mechanical properties of nacre-inspired novel composites.

Demands for high-performance displays with high pixel density and picture quality are ever increasing. Indium gallium nitride (InGaN)-based micro-LEDs (μLEDs) are suitable for meeting such demands owing to their high efficiency, brightness, and stability. However, the poor yield of the pick-and-place technique, defect repair, and visibility of edge lines between modules limit the applications of μLEDs. Furthermore, the external quantum efficiency (EQE) decreases (

Oh, S.-H. and Park, W.S., 2021. Experimental comparison of hydrodynamic characteristics of submerged floating tunnel with different cross-sectional shape. In: Lee, J.L.; Suh, K.-S.; Lee, B.; Shin, S., and Lee, J. (eds.), Crisis and Integrated Management for Coastal and Marine Safety. Journal of Coastal Research, Special Issue No. 114, pp. 46–50. Coconut Creek (Florida), ISSN 0749-0208. This study conducted physical experiments to investigate hydrodynamic characteristics of the submerged floating tunnel (SFT) under wave loading, when the cross-sectional shape of the SFT was either oval or rectangular. By analyzing the experimental data, the performance of the two SFT models were compared with that of the conventional SFT of circular cross-section, which already reported by a previous study (Oh et al., 2013). The experimental results showed that the tensile forces on the tethering lines and the associated wave pressures on the SFT body apparently vary according to the change of the cross-sectional shape of the SFT. In general, the rectangular cross-section was less effective because the tensile forces on the tethering lines and the pressures on the SFT body were greater than those of the oval cross-section.