A Case of Frostbite on Hands due to Liquid Nitrogen.

This study examines a rare case of frostbite on the hands caused by liquid nitrogen, focusing on the scar maturation process. Frostbite is typically less prone to abnormal scarring compared to burns, and this report contrasts the differences in scar maturation between the two. A 31-year-old male hospital employee sustained first- to second-degree frostbite on his gloved hands from a 20-second exposure to liquid nitrogen while changing a cylinder. Conservative treatment was applied, and the patient was monitored for 9 months. The deeply affected area took 50 days to epithelialize but healed without hypertrophic scarring. A mild extension contracture was noted in the distal interphalangeal joint of the right index finger, but the skin remained supple and soft. Incidents of liquid nitrogen-induced frostbite are uncommon, with only 14 cases reported in PubMed® previously. In frostbite, the wound healing involves a slow replacement of damaged connective tissue, which acts as an internal splint, reducing wound contraction. This contrasts with burns, where rapid connective tissue replacement occurs, often leading to significant wound contraction due to the presence of myofibroblasts in granulation tissue. In the presented case, the slow healing process and minimal wound contraction led to mature scarring without abnormalities, underlining a distinctive healing trajectory in frostbite injuries compared to burns.

Management of Scar Contractures of the Hand-Our Therapeutic Strategy and Challenges.

The essence of treating scar contractures lies in covering the skin deficit after releasing the contractures, typically using flaps or skin grafts. However, the specific characteristics of scar contractures, such as their location, shape, and size, vary among patients, which makes surgical planning challenging. To achieve excellent outcomes in the treatment of scar contractures, we have developed a dimensional classification system for these contractures. This system categorizes them into four types: type 1 (superficial linear), type 2-d (deep linear), type 2-s (planar scar contractures confined to the superficial layer), and type 3 (planar scar contractures that reach the deep layer, i.e., three-dimensional scar contractures). Additionally, three factors should be considered when determining surgical approaches: the size of the defect, the availability of healthy skin around the defect, and the blood circulation in the defect bed. Type 1 and type 2-d are linear scars; thus, the scar is excised and sutured in a straight line, and the contracture is released using z-plasty or its modified methods. For type 2-s, after releasing the scar contracture band, local flaps are indicated for small defects, pedicled perforator flaps for medium defects, and free flaps and distant flaps for large defects. Type 2-s has good blood circulation in the defect bed, so full-thickness skin grafting is also a suitable option regardless of the defect's size. In type 3, releasing the deep scar contracture will expose important structures with poor blood circulation, such as tendons, joints, and bones. Thus, a surgical plan using flaps, rather than skin grafts, is recommended. A severity classification and treatment strategy for scar contractures have not yet been established. By objectively classifying and quantifying scar contractures, we believe that better treatment outcomes can be achieved.

Revealing the Hidden Spin-Polarized Bands in a Superconducting Tl Bilayer Crystal.

The interplay of spin-orbit coupling and crystal symmetry can generate spin-polarized bands in materials only a few atomic layers thick, potentially leading to unprecedented physical properties. In the case of bilayer materials with global inversion symmetry, locally broken inversion symmetry can generate degenerate spin-polarized bands, in which the spins in each layer are oppositely polarized. Here, we demonstrate that the hidden spins in a Tl bilayer crystal are revealed by growing it on Ag(111) of sizable lattice mismatch, together with the appearance of a remarkable phenomenon unique to centrosymmetric hidden-spin bilayer crystals: a novel band splitting in both spin and space. The key to success in observing this novel splitting is that the interaction at the interface has just the right strength: it does not destroy the original wave functions of the Tl bilayer but is strong enough to induce an energy separation.

Reconciling scaling of the optical conductivity of cuprate superconductors with Planckian resistivity and specific heat.

Materials tuned to a quantum critical point display universal scaling properties as a function of temperature T and frequency ω. A long-standing puzzle regarding cuprate superconductors has been the observed power-law dependence of optical conductivity with an exponent smaller than one, in contrast to T-linear dependence of the resistivity and ω-linear dependence of the optical scattering rate. Here, we present and analyze resistivity and optical conductivity of La2-xSrxCuO4 with x = 0.24. We demonstrate ℏω/kBT scaling of the optical data over a wide range of frequency and temperature, T-linear resistivity, and optical effective mass proportional to [Formula: see text] corroborating previous specific heat experiments. We show that a T, ω-linear scaling Ansatz for the inelastic scattering rate leads to a unified theoretical description of the experimental data, including the power-law of the optical conductivity. This theoretical framework provides new opportunities for describing the unique properties of quantum critical matter.

Recent Advanced Applications of Ionic Liquid for Future Iontronics.

Recently, electronic devices that make use of a state called the electric double layers (EDL) of ion have opened up a wide range of research opportunities, from novel physical phenomena in solid-state materials to next-generation low-power consumption devices. They are considered to be the future iontronics devices. EDLs behave as nanogap capacitors, resulting the high density of charge carriers is induced at semiconductor/electrolyte by applying only a few volts of the bias voltage. This enables the low-power operation of electronic devices as well as new functional devices. Furthermore, by controlling the motion of ions, ions can be used as semi-permanent charge to form electrets. In this article, we are going to introduce the recent advanced application of iontronics devices as well as energy harvesters making use of ion-based electrets, leading to the future iontronics research.

InternalBrace for Intercarpal Ligament Reconstruction.

SUMMARY: Intercarpal ligament injuries such as scapholunate and lunotriquetral tears are common causes of wrist pain. There is no shortage of surgical techniques to address these injuries, nor is there a lack of literature exploring this topic. However, research progress has not led to a consensus regarding the optimal management of subacute and chronic injuries without articular wear. The senior author (K.C.C.) has performed the spectrum of reconstructive techniques, including dorsal and volar approaches, tendon weaves, ligament tenodesis procedures, reduction and association procedures, and bone-ligament-bone techniques. In the absence of convincing, consistent outcomes, the authors began investigating a novel all-dorsal reconstructive technique using the Arthrex InternalBrace system. The complexity and unpredictable outcomes associated with traditional ligament tenodesis procedures led them to adopt the all-dorsal InternalBrace technique as their primary reconstructive approach. The authors have performed more than 20 procedures with this technique since 2019. In an average tourniquet time of under 60 minutes, they are able to achieve predictable carpal stabilization, pain relief, and restoration of motion. This is the preferred reconstructive approach of the senior author.

A Scoring System That Predicts Difficult Lipoma Resection: Logistic Regression and Tenfold Cross-Validation Analysis.

INTRODUCTION: Most lipomas are readily dissected and removed. However, some cases can pose surgical difficulties. This retrospective study sought to identify clinical and radiological risk factors that predict difficult lipoma resection and can be used in a clinically useful scoring system that predicts difficulty preoperatively. METHODS: The study cohort consisted of all consecutive patients who underwent resection of pathology-confirmed lipoma during 2016-2018 at a tertiary care referral center in Tokyo, Japan. Surgical difficulty was defined as difficulty separating some/all of the tumor from the surrounding tissue by hand and inability to extract the tumor in one piece. Descriptive, univariate, and multivariate logistic regression analyses were conducted to identify predictive factors. The predictive accuracy of the scoring system that included these factors was assessed by tenfold cross-validation analysis. Receiver-operating curve (ROC) analysis was conducted to identify the optimal cutoff score for predicting surgical difficulty. RESULTS: Of the 86 cases, 36% involved surgical difficulty. Multivariate analysis showed that subfascial intramuscular location (odds ratio 42.7, 95% confidence interval 3.0-608.0), broad touching of underlying structures (46.5, 3.7-586.0), in-flowing blood vessels (9.3, 1.1-78.5), and unclear boundaries (109.0, 1.1-1110.0) significantly predicted surgical difficulty. These factors were used to construct a 0-4 point scoring system (with one point per variable). On cross-validation, the accuracy of the scoring system was 82.4% (Cohen's kappa of 0.57). ROC analysis showed that scores ≥ 2 predicted surgical difficulty with sensitivity and specificity of 55% and 98%, respectively. CONCLUSIONS: Our scoring system accurately predicted lipoma resection difficulty and may help operators prepare, thereby facilitating surgery.

Multidetector-Row Computed Tomographic Analysis of the Superficial Palmar Branch of Radial Artery Perforator Flaps.

BACKGROUND: Soft-tissue defects in the hand and digits can be effectively covered by using the free superficial palmar branch of the radial artery (SPBRA) flap, which is harvested from the radial volar wrist. Because previous anatomical studies on this flap are limited, multidetector-row computed tomographic angiography of the upper limbs was conducted to characterize the three-dimensional anatomical structure of the SPBRA and its perforators in living patients. METHODS: This retrospective anatomical study was conducted from 2014 to 2019. All data from Digital Imaging and Communications in Medicine were analyzed by using their viewer. SPBRA diameter and the location where it bifurcated from the radial artery were recorded, as were the number, location, branching patterns, and diameters of its perforators and their lengths. RESULTS: In total, 30 patients met all eligibility criteria. All had the SPBRA. The vessel bifurcated from the radial artery on average 13.2 mm proximally from the radial styloid process. The 30 patients had 40 SPBRA perforators in total. Their average SPBRA-to-dermis length was 6.43 mm. All patients had at least one direct cutaneous perforator. Nine and one also had one musculocutaneous perforator and another direct perforator, respectively. All direct cutaneous perforators were located inside a 16.4-mm-diameter circle with an origin on the scaphoid tubercle. The mean diameters of the SPBRA and its perforators were 1.12 and 0.62 mm, respectively. CONCLUSIONS: All patients had at least one reliable SPBRA perforator in the radial volar wrist. The authors' results suggest that plastic surgeons can easily and safely plan the SPBRA flap design, potentially without preoperative perforator mapping.

Older Patients and Patients with Severe Arteriosclerosis Are Less Likely to Develop Keloids and Hypertrophic Scars after Thoracic Midline Incision: A Survey-Based Analysis of 328 Cases.

BACKGROUND: Surgery is a well-known trigger of keloid and hypertrophic scarring. Sternotomy scars are subject to high skin tension, which is known to promote pathologic scarring. This suggests that sternotomies in adults are associated with high pathologic scarring rates, which aligns with the authors' anecdotal experience. However, this notion has never been examined formally. Therefore, the authors conducted a survey-based cohort study of patients who had undergone a sternotomy. METHODS: All consecutive Japanese adults (18 years of age or older) who underwent cardiovascular surgery with sternotomy in 2014 to 2017 were identified in 2019 by chart review and sent a questionnaire. Respondents formed the study cohort. The questionnaire presented randomly ordered photographs of representative mature, keloid, and hypertrophic scars and asked the patients to choose the image that best resembled their midline scar when it was particularly noticeable. The incidence of self-reported pathologic scarring (keloids and hypertrophic scars were grouped together) and the patient demographic (age and sex) and clinical characteristics (intima-media thickness of the left and right common and internal carotid arteries) that were associated with pathologic scarring were determined. RESULTS: Of the 548 patients who underwent sternotomy, 328 responded for a 60 percent response rate. The mean patient age was 67 years, and 68.0 percent were male. Of these patients, 195 (59.5 percent) reported they had a pathologic scar. Compared with patients who had a mature scar, patients who had a pathologic scar had younger mean age (65 versus 69 years; p = 0.0002) and lower intima-media thickness (0.92 versus 1.05 mm; p = 0.028). CONCLUSIONS: Sternotomy was associated with a high rate of pathologic scarring. Older age and arteriosclerosis were associated with less pathologic scarring. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, III.

Electrical mapping of thermoelectric power factor in WO3 thin film.

With growing environmental awareness and considerable research investment in energy saving, the concept of energy harvesting has become a central topic in the field of materials science. The thermoelectric energy conversion, which is a classic physical phenomenon, has emerged as an indispensable thermal management technology. In addition to conventional experimental investigations of thermoelectric materials, seeking promising materials or structures using computer-based approaches such as machine learning has been considered to accelerate research in recent years. However, the tremendous experimental efforts required to evaluate materials may hinder us from reaping the benefits of the fast-developing computer technology. In this study, an electrical mapping of the thermoelectric power factor is performed in a wide temperature-carrier density regime. An ionic gating technique is applied to an oxide semiconductor WO3, systematically controlling the carrier density to induce a transition from an insulating to a metallic state. Upon electrically scanning the thermoelectric properties, it is demonstrated that the thermoelectric performance of WO3 is optimized at a highly degenerate metallic state. This approach is convenient and applicable to a variety of materials, thus prompting the development of novel functional materials with desirable thermoelectric properties.

Incidence of and risk factors for self-load-related and medical device-related pressure injuries in critically ill patients: A prospective observational cohort study.

There are two types of pressure injuries: self-load-related pressure injuries (PIs) and medical device-related pressure injuries (MDRPIs), but the differences in risk factors between PIs and MDRPIs have not yet been clarified. If risk factors for PIs and MDRPIs differ, preventive interventions should take this into account. This is a prospective cohort study aimed to determine the cumulative incidence of PIs and MDRPIs in critically ill patients and to identify corresponding risk factors. The study included 1418 patients who were admitted to the critical care medical center of a single university hospital in Tokyo, Japan, between 1 December 2019 and 31 August 2020. The Kaplan-Meier method was used to calculate the cumulative incidence of PIs and MDRPIs. Furthermore, the Cox proportional hazards model was used to analyse the predictors in both the PI and MDRPI incidence and non-incidence groups. Predictors were based on data from the 0th disease day. The cumulative incidence of PIs and MDRPIs was 4.6/1000 person-days and 3.6/1000 person-days, respectively. Multivariate analysis using the Cox proportional hazards model showed that common risk factors for the occurrence of PIs and MDRPIs were possession of PI on admission, higher blood lactate, blood purification therapy, and positional restriction. The risk factors for PIs only were diabetes mellitus, septic shock, and a lower serum albumin level, while the risk factors for MDRPIs only were the D-dimer level and extracorporeal membranous oxygenation treatment. Therefore, prophylactic interventions need to consider these different risk factors.

Oxidation-induced thermopower inversion in nanocrystalline SnSe thin film.

Given the growing demand for environmentally friendly energy sources, thermoelectric energy conversion has attracted increased interest as a promising CO2-free technology. SnSe single crystals have attracted attention as a next generation thermoelectric material due to outstanding thermoelectric properties arising from ultralow thermal conductivity. For practical applications, on the other hand, polycrystalline SnSe should be also focused because the production cost and the flexibility for applications are important factors, which requires the systematic investigation of the stability of thermoelectric performance under a pseudo operating environment. Here, we report that the physical properties of SnSe crystals with nano to submicron scale are drastically modified by atmospheric annealing. We measured the Seebeck effect while changing the annealing time and found that the large positive thermopower, + 757 µV K-1, was completely suppressed by annealing for only a few minutes and was eventually inverted to be the large negative value, - 427 µV K-1. This result would further accelerate intensive studies on SnSe nanostructures, especially focusing on the realistic device structures and sealing technologies for energy harvesting applications.

The History of Propeller Flaps.

Several pedicled flaps were developed by Hyakusoku at the Nippon Medical School Hospital, Tokyo, Japan, in the 1980s to treat a large number of patients with postburn contractures. In this setting, the propeller flaps were described for the first time in 1991. The term propeller was used because of the blade shape of the skin island rotating on its axis. In 1989, Koshima introduced the term perforator flaps , whereas Hallock, in 2006, applied the perforator flap concept to the propeller flap. The name perforator pedicled propeller flap followed. Propeller flap had developed to be an important operative technique and a hot topic in the field of reconstructive microsurgery, with the important contribution of Teo. In 2009, the First Tokyo Meeting on Perforator and Propeller Flaps was held, where Pignatti reported the consensus on the definition and classification of propeller flaps that was given by the advisory panel of the meeting. Further evolutions developed since then will be described in this dedicated issue of Seminars of Plastic Surgery .

Our Definition of Propeller Flaps and Their Classification.

The term propeller flap was introduced for the first time by Hyakusoku to define an island flap, based on a subcutaneous pedicle hub, that was rotated 90 degrees to correct scar contractures due to burns. With the popularization of perforator flaps, the propeller movement was applied for the first time to a skin island vascularized only by an isolated perforator, and the terms propeller and perforator flap were used together. Thereafter, the surgical technique of propeller flaps evolved and new applications developed. With the "Tokyo consensus," we proposed a definition and a classification schema for propeller flaps. A propeller flap was defined as an "island flap that reaches the recipient site through an axial rotation." The classification included the SPP (SPP) flap, the perforator pedicled propeller (PPP) flap, and the supercharged PPP (SCP) flap. A recent update added a new category, the axial pedicled propeller (APP) flap. Here we propose our updated and comprehensive classification of propeller flaps, taking into account the previous classification and subsequent publications. Based on their vascular pedicle, we consider the following five types of propellers: (1) SPP flap, 2.PPP flap, its subtype (2a) SCP flap, (3) APP flap, (4) muscle propeller flap, and (5) chimeric propeller flap. The variables that can be taken into account in the classification are as follows: type of nourishing pedicle, degrees of skin island rotation, position of the nourishing pedicle, artery of origin of the pedicle, and flap shape.

Imaging in Propeller Flap Surgery.

Since propeller flaps are elevated as island flaps and most often nourished by a single perforator nearby the defect, it is challenging to change the flap design intraoperatively when a reliable perforator cannot be found where expected to exist. Thus, accurate preoperative mapping of perforators is essential in the safe planning of propeller flaps. Various methods have been reported so far: (1) handheld acoustic Doppler sonography (ADS), (2) color duplex sonography (CDS), (3) perforator computed tomographic angiography (P-CTA), and (4) magnetic resonance angiography (MRA). To facilitate the preoperative perforator assessment, P-CTA is currently considered as the gold standard imaging tool in revealing the three-dimensional anatomical details of perforators precisely. Nevertheless, ADS remains the most widely used tool due to its low cost, faster learning, and ease of use despite an undesirable number of false-positive results. CDS can provide hemodynamic characteristics of the perforator and is a valid and safer alternative particularly in patients in whom ionizing radiation and/or contrast exposure should be limited. Although MRA is less accurate in detecting smaller perforators of caliber less than 1.0 mm and the intramuscular course of perforators at the present time, MRA is expected to improve in the future due to the recent developments in technology, making it as accurate as P-CTA. Moreover, it provides the advantage of being radiation-free with fewer contrast reactions.

N- and O-arylation of pyridin-2-ones with diaryliodonium salts: base-dependent orthogonal selectivity under metal-free conditions.

Metal-free N- and O-arylation reactions of pyridin-2-ones as ambident nucleophiles have been achieved with diaryliodonium salts on the basis of base-dependent chemoselectivity. In the presence of N,N-diethylaniline in fluorobenzene, pyridin-2-ones were very selectively converted to N-arylated products in high yields. On the other hand, the O-arylation reactions smoothly proceeded with the use of quinoline in chlorobenzene, leading to high yields and selectivities. In these methods, a variety of pyridin-2-ones in addition to pyridin-4-one and a set of diaryliodonium salts were accepted as suitable reaction partners.

The actual electronic band structure of a rubrene single crystal.

A proper understanding on the charge mobility in organic materials is one of the key factors to realize highly functionalized organic semiconductor devices. So far, however, although a number of studies have proposed the carrier transport mechanism of rubrene single crystal to be band-like, there are disagreements between the results reported in these papers. Here, we show that the actual dispersion widths of the electronic bands formed by the highest occupied molecular orbital are much smaller than those reported in the literature, and that the disagreements originate from the diffraction effect of photoelectron and the vibrations of molecules. The present result indicates that the electronic bands would not be the main channel for hole mobility in case of rubrene single crystal and the necessity to consider a more complex picture like molecular vibrations mediated carrier transport. These findings open an avenue for a thorough insight on how to realize organic semiconductor devices with high carrier mobility.

Efficiency in Digital and Hand Replantation.

The literature on surgical techniques and recent evidence in microsurgical digital and hand replantation is reviewed. Replantation should not be done routinely without considering postoperative functional outcomes. Achieving best outcomes is related to the success of microvascular anastomosis and to adequacy of bone fixation, tendon and nerve repair, and soft-tissue coverage. Replantation surgery has become a routine procedure. However, little is known about the decision-making process for digital and hand amputation. A study comparing the outcomes of digital and hand amputations treated with replantation or revision amputation is needed. Outcome assessment includes not only function but also patient-reported outcomes.

Electric-field control of magnetism in a few-layered van der Waals ferromagnetic semiconductor.

Manipulating a quantum state via electrostatic gating has been of great importance for many model systems in nanoelectronics. Until now, however, controlling the electron spins or, more specifically, the magnetism of a system by electric-field tuning has proven challenging1-4. Recently, atomically thin magnetic semiconductors have attracted significant attention due to their emerging new physical phenomena5-13. However, many issues are yet to be resolved to convincingly demonstrate gate-controllable magnetism in these two-dimensional materials. Here, we show that, via electrostatic gating, a strong field effect can be observed in devices based on few-layered ferromagnetic semiconducting Cr2Ge2Te6. At different gate doping, micro-area Kerr measurements in the studied devices demonstrate bipolar tunable magnetization loops below the Curie temperature, which is tentatively attributed to the moment rebalance in the spin-polarized band structure. Our findings of electric-field-controlled magnetism in van der Waals magnets show possibilities for potential applications in new-generation magnetic memory storage, sensors and spintronics.

Triboelectric energy harvesting with surface-charge-fixed polymer based on ionic liquid.

A novel triboelectric energy harvester has been developed using an ionic liquid polymer with cations fixed at the surface. In this report, the fabrication of the device and the characterization of its energy harvesting performance are detailed. An electrical double layer was induced in the ionic liquid polymer precursor to attract the cations to the surface where they are immobilized using a UV-based crosslinking reaction. The finalized polymer is capable of generating an electrical current when contacted by a metal electrode. Using this property, energy harvesting experiments were conducted by cyclically contacting a gold-surface electrode with the charge fixed surface of the polymer. Control experiments verified the effect of immobilizing the cations at the surface. By synthesizing a polymer with the optimal composition ratio of ionic liquid to macromonomer, an output of 77 nW/cm2 was obtained with a load resistance of 1 MΩ at 1 Hz. This tuneable power supply with a µA level current output may contribute to Internet of Things networks requiring numerous sensor nodes at remote places in the environment.