A comparative study on the application of different endoscopic diagnostic methods in the differential diagnosis of benign and malignant bile duct strictures.

Objective: To compare the diagnostic value of cytobrush, ERCP-guided biopsy, SpyGlass direct visual impression and SpyGlass-guided biospy (SpyBite) in the differential diagnosis of benign and malignant bile duct strictures. Methods: The data of 1,008 patients who were clinically diagnosed with indeterminate biliary strictures and underwent ERCP-guided biopsy, cytobrush, SpyGlass direct visual impression or SpyBite at the First Affiliated Hospital of Nanchang University between January 2010 and December 2019 were collected and analyzed retrospectively. The final diagnose was determined by surgical pathological specimen or follow-up (Malignant stricture can be identified if the stricture showed malignant progression during one year of follow-up). The differential diagnostic value of the above endoscopic diagnostic methods was evaluated by means of sensitivity, specificity, accuracy, positive predictive value, negative predictive value, etc. and safety was evaluated by the incidence rate of adverse events. Results: In terms of sensitivity, standard biopsy group (48.6%) and SpyBite group (61.5%) were significantly higher than cytobrush group (32.0%), and visual impression group (100%) was significantly higher than any other group. As far as specificity was concerned, cytobrush group (99.0%), standard biopsy group (99.3%) and the SpyBite group (100%) were significantly higher than visual impression (55.6%), but there was no statistical difference among the three groups above. As far as accuracy was concerned, standard biopsy group (65.3%), and SpyBite group (80.0%) were significantly higher than cytobrush group (44.4%), and SpyBite group (80.0%) was significantly higher than visual impression group (54.8%). In terms of safety, visual impression group and SpyBite group were significantly higher than cytobrush group and standard biopsy group in post-ERCP cholangitis. Conclusion: SpyBite combined with SpyGlass-guided visual impression was better for differential diagnosis of benign and malignant bile duct strictures in terms of sensitivity and accuracy compared with conventional endoscopic diagnostic methods such as cytobrush and standard biopsy. Furthmore, the incidence rates of adverse events after SpyGlass examination was similar to those after conventional endoscopic diagnostic methods except for higher cholangitis, which could be controlled by antibiotics and might be avoided by adequate biliary drainage.

Crack mechanism and experimental verification on straightening of AZ31B magnesium alloy plate.

When plates with edge cracks in the rolling process is straightened by cyclic tensile and compressive stress, the tip of edge crack always accompanied by stress concentration, which leads to crack propagation. In this paper, damage parameters are imported into the plate straightening model based on determining the GTN damage parameters of magnesium alloy materials by inverse finite element calibration method, the influence of different straightening process schemes and prefabricated V-shaped crack geometry on crack growth is analyzed through the way of the combination of simulation and straightening experiment. The results show that the peak values of equivalent stress and equivalent strain under each straightening roll appear at the crack tip. The value of longitudinal stress and equivalent stain decrease with the distance to crack tip becomes larger. The peak value of longitudinal stress appears when the crack circumferential angle is about 100°, and the crack tip is easy to form crack propagation; when the plate passes roll 2 and roll 4, the equivalent stress and strain concentration at the crack tip are most obvious; when the reduction reaches a certain degree, the void volume fraction (VVF) reaches the VVF of the material breaking; with the increase of the entrance reduction, the number of VVF at the crack tip which reaches the material fracture increases, and the length of crack propagation increases; the stress concentration at the tip of V-shaped crack with large length-width ratio is obvious, and the VVF is more likely to reach the VVF at the time of material fracture, crack initiates and propagates easily.

Robust Tunable Large-Gap Quantum Spin Hall States in Monolayer Cu2S on Insulating Substrates.

Quantum spin Hall (QSH) insulators with large band gaps and dissipationless edge states are of both technological and scientific interest. Although numerous two-dimensional (2D) systems have been predicted to host the QSH phase, very few of them harbor large band gaps and retain their nontrivial band topology when they are deposited on substrates. Here, based on a first-principles analysis with hybrid functional calculations, we investigated the electronic and topological properties of inversion-asymmetric monolayer copper sulfide (Cu2S). Interestingly, we found that monolayer Cu2S possesses an intrinsic QSH phase, Rashba spin splitting, and a large band gap of 220 meV that is suitable for room-temperature applications. Most importantly, we constructed heterostructures of a Cu2S film on PtTe2, h-BN, and Cu(111) substrates and found that the topological properties remain preserved upon an interface with these substrates. Our findings suggest Cu2S as a possible platform to realize inversion-asymmetric QSH insulators with potential applications in low-dissipation electronic devices.

Prediction of topological Dirac semimetal in Ca-based Zintl layered compounds CaM2X2 (M = Zn or Cd; X = N, P, As, Sb, or Bi).

Topological Dirac materials are attracting a lot of attention because they offer exotic physical phenomena. An exhaustive search coupled with first-principles calculations was implemented to investigate 10 Zintl compounds with a chemical formula of CaM2X2 (M = Zn or Cd, X = N, P, As, Sb, or Bi) under three crystal structures: CaAl2Si2-, ThCr2Si2-, and BaCu2S2-type crystal phases. All of the materials were found to energetically prefer the CaAl2Si2-type structure based on total ground state energy calculations. Symmetry-based indicators are used to evaluate their topological properties. Interestingly, we found that CaM2Bi2 (M = Zn or Cd) are topological crystalline insulators. Further calculations under the hybrid functional approach and analysis using k · p model reveal that they exhibit topological Dirac semimetal (TDSM) states, where the four-fold degenerate Dirac points are located along the high symmetry line in-between Г to A points. These findings are verified through Green's function surface state calculations under HSE06. Finally, phonon spectra calculations revealed that CaCd2Bi2 is thermodynamically stable. The Zintl phase of AM2X2 compounds have not been identified in any topological material databases, thus can be a new playground in the search for new topological materials.

Doping limitation due to self-compensation by native defects in In-doped rocksalt CdxZn1-xO.

Cadmium oxide (CdO)-ZnO alloys (CdxZn1-xO) exhibit a transformation from the wurtzite to the rocksalt (RS) phase at a CdO composition of ∼70% with a drastic change in the band gap and electrical properties. RS-CdxZn1-xO alloys (x> 0.7) are particularly interesting for transparent conductor applications due to their wide band gap and high electron mobility. In this work, we synthesized RS-CdxZn1-xO alloys doped with different concentrations of In dopants and evaluated their electrical and optical properties. Experimental results are analyzed in terms of the amphoteric native defect model and compared directly to defect formation energies obtained by hybrid density functional theory (DFT) calculations. A saturation in electron concentration of ∼7 × 1020 cm-3accompanied by a rapid drop in electron mobility is observed for the RS-CdxZn1-xO films with 0.7 ⩽x< 1 when the In dopant concentration [In] is larger than 3%. Hybrid DFT calculations confirm that the formation energy of metal vacancy acceptor defects is significantly lower in RS-CdxZn1-xO than in CdO, and hence limits the free carrier concentration. Mobility calculations reveal that due to the strong compensation by native defects, RS-CdxZn1-xO alloys exhibit a compensation ratio of >0.7 for films withx< 0.8. As a consequence of the compensation by native defects, in heavily doped RS-CdxZn1-xO carrier-induced band filling effect is limited. Furthermore, the much lower mobility of the RS-CdxZn1-xO alloys also results in a higher resistivity and reduced transmittance in the near infra-red region (λ > 1100 nm), making the material not suitable as transparent conductors for full spectrum photovoltaics.

Challenging Diagnosis and Endoscopic Management of Dieulafoy's Lesion-Induced Small-Bowel Bleeding: A Case Report.

Small-bowel bleeding is a relatively uncommon event of gastrointestinal bleeding. Some causes of small-bowel bleeding, such as vascular lesions, are still challenging to confirm, despite the use of various diagnostic modalities (e.g., capsule endoscopy, deep enteroscopy, and radiographic imaging). Vascular lesion-induced bleeding tends to be insidious and intermittent, but sometimes it can be massive and fatal, so that the timing of an endoscopy is critical. We describe herein the case of an elderly female patient with Dieulafoy's lesion-induced small-bowel bleeding presenting with recurrent melena. In this article, we describe how the cause of her bleeding was found and how the bleeding was stopped endoscopically. Finally, we discuss the characteristics of a small-bowel Dieulafoy's lesion and its endoscopic treatment.

Anisotropic Rashba splitting in Pt-based Janus monolayers PtXY (X,Y = S, Se, or Te).

Recent studies have demonstrated the feasibility of synthesizing two-dimensional (2D) Janus materials which possess intrinsic structural asymmetry. Hence, we performed a systematic first-principles study of 2D Janus transition metal dichalcogenide (TMD) monolayers based on PtXY (X,Y = S, Se, or Te). Our calculated formation energies show that these monolayer Janus structures retain the 1T phase. Furthermore, phonon spectral calculations confirm that these Janus TMD monolayers are thermodynamically stable. We found that PtSSe, PtSTe, and PtSeTe exhibit an insulating phase with indirect band gaps of 2.108, 1.335, and 1.221 eV, respectively, from hybrid functional calculations. Due to the breaking of centrosymmetry in the crystal structure, the spin-orbit coupling (SOC)-induced anisotropic Rashba splitting is observed around the M point. The calculated Rashba strengths from M to Γ (α M-Γ R) are 1.654, 1.103, and 0.435 eV Å-1, while the calculated values from M to K (α M-K R) are 1.333, 1.244, and 0.746 eV Å-1, respectively, for PtSSe, PtSTe, and PtSeTe. Interestingly, the spin textures reveal that the spin-splitting is mainly attributed to the Rashba effect. However, a Dresselhaus-like contribution also plays a secondary role. Finally, we found that the band gaps and the strength of the Rashba effect can be further tuned through biaxial strain. Our findings indeed show that Pt-based Janus TMDs demonstrate the potential for spintronics applications.

Spin-orbit quantum impurity in a topological magnet.

Quantum states induced by single-atomic impurities are at the frontier of physics and material science. While such states have been reported in high-temperature superconductors and dilute magnetic semiconductors, they are unexplored in topological magnets which can feature spin-orbit tunability. Here we use spin-polarized scanning tunneling microscopy/spectroscopy (STM/S) to study the engineered quantum impurity in a topological magnet Co3Sn2S2. We find that each substituted In impurity introduces a striking localized bound state. Our systematic magnetization-polarized probe reveals that this bound state is spin-down polarized, in lock with a negative orbital magnetization. Moreover, the magnetic bound states of neighboring impurities interact to form quantized orbitals, exhibiting an intriguing spin-orbit splitting, analogous to the splitting of the topological fermion line. Our work collectively demonstrates the strong spin-orbit effect of the single-atomic impurity at the quantum level, suggesting that a nonmagnetic impurity can introduce spin-orbit coupled magnetic resonance in topological magnets.

Endoscope-assisted Surgery in the Treatment of Dentigerous Cyst Involving the Maxillary Sinus - Report of Two Cases.

Endoscopic techniques have been applied to oral and maxillofacial surgeries. Previous studies have proved their practicability in the treatment of osteomyelitis of the mandible and displaced residual roots in the maxillary sinus. In this report, two patients with dentigerous cysts in the maxillary sinus underwent endoscope-assisted curettage. Both patients were successfully cured without recurrent lesions or any complications. The follow-up found that the bone cavities had shrunk. An endoscope-assisted Caldwell-Luc operation provided clear visibility of the surgical field and preserved the mucosa of the maxillary sinus.

HOT Graphene and HOT Graphene Nanotubes: New Low Dimensional Semimetals and Semiconductors.

We report a new graphene allotrope named HOT graphene containing carbon hexagons, octagons, and tetragons. A corresponding series of nanotubes are also constructed by rolling up the HOT graphene sheet. Ab initio calculations are performed on geometric and electronic structures of the HOT graphene and the HOT graphene nanotubes. Dirac cone and high Fermi velocity are achieved in a non-hexagonal structure of HOT graphene, implying that the honeycomb structure is not an indispensable condition for Dirac fermions to exist. HOT graphene nanotubes show distinctive electronic structures depending on their topology. The (0,1) n (n ≥ 3) HOT graphene nanotubes reveal the characteristics of semimetals, while the other set of nanotubes (1,0) n shows continuously adjustable band gaps (0~ 0.51 eV) with tube size. A competition between the curvature effect and the zone-folding approximation determines the band gaps of the (1,0) n nanotubes. Novel conversion between semimetallicity and semiconductivity arises in ultra-small tubes (radius < 4 Å, i.e., n < 3).

Quantum Phase Transition of Correlated Iron-Based Superconductivity in LiFe_{1-x}Co_{x}As.

The interplay between unconventional Cooper pairing and quantum states associated with atomic scale defects is a frontier of research with many open questions. So far, only a few of the high-temperature superconductors allow this intricate physics to be studied in a widely tunable way. We use scanning tunneling microscopy to image the electronic impact of Co atoms on the ground state of the LiFe_{1-x}Co_{x}As system. We observe that impurities progressively suppress the global superconducting gap and introduce low energy states near the gap edge, with the superconductivity remaining in the strong-coupling limit. Unexpectedly, the fully opened gap evolves into a nodal state before the Cooper pair coherence is fully destroyed. Our systematic theoretical analysis shows that these new observations can be quantitatively understood by the nonmagnetic Born-limit scattering effect in an s±-wave superconductor, unveiling the driving force of the superconductor to metal quantum phase transition.

Engineering Surface Structure of Spinel Oxides via High-Valent Vanadium Doping for Remarkably Enhanced Electrocatalytic Oxygen Evolution Reaction.

Spinel oxides (AB2O4) with unique crystal structures have been widely explored as promising alternative catalysts for efficient oxygen evolution reactions; however, developing novel methods to fabricate robust, cost-effective, and high-performance spinel oxide based electrocatalysts is still a great challenge. Here, utilizing a complementary experimental and theoretical approach, pentavalent vanadium doping in the spinel oxides (i.e., Co3O4 and NiFe2O4) has been thoroughly investigated to engineer their surface structures for the enhanced electrocatalytic oxygen evolution reaction. Specifically, when the optimal concentration of vanadium (ca. 7.7 at. %) is incorporated into Co3O4, the required overpotential to reach a certain jGEOM and jECSA decreases dramatically for oxygen evolution reactions in alkaline media. Even after 30 h of chronopotentiometry, the required potential for V-doped Co3O4 just increases by 16.3 mV, being much lower than that of the undoped one. It is observed that the pentavalent vanadium doping introduces lattice distortions and defects on the surface, which in turn exposes more active sites for reactions. DFT calculations further reveal the rate-determining step changing from the step of *-O to *-OOH to the step of *-OH to *-O, while the corresponding energy barriers decrease from 1.73 to 1.57 eV accordingly after high-valent V doping. Moreover, the oxygen intermediate probing method using methanol as a probing reagent also demonstrates a stronger OH* adsorption on the surface after V doping. When vanadium doping is performed in the inverse spinel matrix of NiFe2O4, impressive performance enhancement in the oxygen evolution reaction is as well witnessed. All these results clearly illustrate that the V doping process can not only efficiently improve the electrochemical properties of spinel transition metal oxides but also provide new insights into the design of high-performance water oxidation electrocatalysts.

Atomically precise bottom-up synthesis of π-extended [5]triangulene.

The zigzag-edged triangular graphene molecules (ZTGMs) have been predicted to host ferromagnetically coupled edge states with the net spin scaling with the molecular size, which affords large spin tunability crucial for next-generation molecular spintronics. However, the scalable synthesis of large ZTGMs and the direct observation of their edge states have been long-standing challenges because of the molecules' high chemical instability. Here, we report the bottom-up synthesis of π-extended [5]triangulene with atomic precision via surface-assisted cyclodehydrogenation of a rationally designed molecular precursor on metallic surfaces. Atomic force microscopy measurements unambiguously resolve its ZTGM-like skeleton consisting of 15 fused benzene rings, while scanning tunneling spectroscopy measurements reveal edge-localized electronic states. Bolstered by density functional theory calculations, our results show that [5]triangulenes synthesized on Au(111) retain the open-shell π-conjugated character with magnetic ground states.

Controlling the Polarity of the Molecular Beam Epitaxy Grown In-Bi Atomic Film on the Si(111) Surface.

Synchrotron radiation core-level photoemission spectroscopy, scanning tunneling microscopy (STM), and first-principles calculations have been utilized to explore the growth processes and the atomic structure of the resulting films during the two-step molecular beam epitaxy (MBE) of In and Bi on the Si(111) surface. Deposition of 1.0-ML Bi on the In/Si(111)-(4 × 1) surface at room temperature results in Bi-terminated BiIn-(4 × 3) structures, which are stable up to ~300 °C annealing. By contrast, deposition of In on the ß-Bi/Si(111)-(√3 × âˆš3) surface at room temperature results in three dimensional (3D) In islands. In both cases, annealing at 460 °C results in the same In-terminated In0.75Bi/Si(111)-(2 × 2) surface. Our DFT calculations confirm that the surface energy of In-terminated In0.75Bi/Si(111)-(2 × 2) system is lower than that of Bi-terminated Bi0.75In/Si(111)-(2 × 2). These findings provide means for the control of the polarity of the MBE In-Bi atomically thick films.

Value of a smartphone-compatible thermal imaging camera in the detection of peroneal artery perforators: Comparative study with computed tomography angiography.

BACKGROUND: The aim of this study was to investigate the value of a smartphone-compatible thermal imaging camera in the mapping of the peroneal artery perforators. METHODS: Twelve consecutive patients scheduled for fibular flap reconstruction were enrolled. The lower limbs were first studied using smartphone-based dynamic infrared thermography (DIRT). During the rewarming, the hotspots were marked, small rubber markers were taped to the registered sites, and then the patients were sent for a CT scan. The diagnostic performance of smartphone-based DIRT was evaluated by comparing the DIRT findings with CT angiography and intraoperative findings. RESULTS: DIRT detected 42 of the 57 dominant perforators in 24 limbs and resulted in a sensitivity of 73.7% and a positive predictive value of 65.6%. CONCLUSIONS: The sensitivity and positive predictive value of the smartphone-based DIRT are low. Currently, it should be used as an adjunctive tool together with the established imaging techniques.

Computer-assisted resection and reconstruction of bilateral osteoradionecrosis of the mandible using 2 separate flaps prepared from a single fibula.

OBJECTIVES: Osteoradionecrosis of the mandible is a late radiation-induced complication, which is a major concern in survivors of head and neck cancer. STUDY DESIGN: In this study, we present a case of a patient with nasopharyngeal carcinoma who developed extensive bilateral osteoradionecrosis of the ascending ramus of the mandible. After preoperative virtual surgical planning, the obtained data were used to fabricate patient-specific cutting templates. The bilateral mandibular defects were reconstructed using 2 separate flaps prepared from a single fibula. RESULTS: Both defects were successfully reconstructed, and satisfactory aesthetic and functional results were achieved. CONCLUSIONS: Bilateral mandibular osteoradionecrosis can be managed with virtual surgical planning, and the defects can be reconstructed using 2 separate flaps prepared from a single fibula.

Prediction of Quantum Anomalous Hall Effect in MBi and MSb (M:Ti, Zr, and Hf) Honeycombs.

The abounding possibilities of discovering novel materials has driven enhanced research effort in the field of materials physics. Only recently, the quantum anomalous hall effect (QAHE) was realized in magnetic topological insulators (TIs) albeit existing at extremely low temperatures. Here, we predict that MPn (M =Ti, Zr, and Hf; Pn =Sb and Bi) honeycombs are capable of possessing QAH insulating phases based on first-principles electronic structure calculations. We found that HfBi, HfSb, TiBi, and TiSb honeycomb systems possess QAHE with the largest band gap of 15 meV under the effect of tensile strain. In low-buckled HfBi honeycomb, we demonstrated the change of Chern number with increasing lattice constant. The band crossings occurred at low symmetry points. We also found that by varying the buckling distance we can induce a phase transition such that the band crossing between two Hf d-orbitals occurs along high-symmetry point K2. Moreover, edge states are demonstrated in buckled HfBi zigzag nanoribbons. This study contributes additional novel materials to the current pool of predicted QAH insulators which have promising applications in spintronics.

Comparison of outcomes with extensive segmental pectoralis major myocutaneous flap via the anterior axillary line and the conventional technique in oral and oropharyngeal cancer.

BACKGROUND: This study compared the outcomes of an extensive segmental pectoralis major myocutaneous flap (esPMMF) and a conventional pectoralis major myocutaneous flap (PMMF). METHODS: The study enrolled 91 patients with primary oral and oropharyngeal squamous cell carcinoma (SCC) who underwent radical resection followed by reconstruction of the defect using either an esPMMF via the anterior axillary line or a PMMF. The pedicle lengths of the esPMMF and PMMF were 22-28 and 18-22 cm, respectively. The esPMMF and PMMF had skin paddle dimensions of 5 × 8 to 7 × 14 cm and 6 × 7 to 8 × 17 cm, respectively. RESULTS: The esPMMF pedicle was longer than that of the PMMF. The range of shoulder abduction was significantly greater in the esPMMF group and the donor-site aesthetic results were better. CONCLUSION: The esPMMF has a longer pedicle flap, enables a greater range of shoulder abduction, and has a better aesthetic result than the conventional technique.

IncRNA H19 promotes tongue squamous cell carcinoma progression through ß-catenin/GSK3ß/EMT signaling via association with EZH2.

H19 is involved in tumor metastasis and associated with tumor progression. Enhancer of zest homolog 2 (EZH2) is overexpressed in multiple cancer types and correlates with tumor proliferation, epithelial-mesenchymal transition, and poor prognosis. However, the interaction between H19 and EZH2 to promote tongue squamous cell carcinoma (TSCC) progression remains largely uncharacterized. Insitu hybridization and quantitative reverse-transcription PCR (qRT-PCR) were performed to measure H19 expression in primary TSCC and adjacent normal tissues and cell lines. EZH2 expression was determined by immunohistochemistry in matched primary TSCC and adjacent normal tissues. The correlation between H19 and EZH2 expression and clinicopathological characteristics were analyzed. The roles of H19 in cell proliferation, apoptosis, and invasion were analyzed using a H19-targeted lentivirus. Western blot and qRT-PCR were carried out to detect downstream signal pathway changes. Expression levels of downstream signaling proteins in primary TSCC tissues and adjacent normal tissues were analyzed by immunohistochemistry. H19 and EZH2 were upregulated in TSCC tissues compared to matched normal tissues, and significantly correlated with WHO grade, lymph node metastasis, and poor prognosis. H19 silencing attenuated cell proliferation, apoptosis, and invasion in vitro. H19 knockdown inhibited the activation of ß-catenin/GSK-3ß/cyclin D1/c-myc, upregulated E-cadherin and zonula occludens-1 (ZO-1), and inhibited N-cadherin, vimentin, Snail1, Twist1, and ZEB1. Silencing H19 expression also inhibited tumor progression and lung metastasis in an animal model. Our findings indicate that H19 promotes TSCC progression through association with EZH2, and affects downstream ß-Catenin/GSK3ß/EMT signaling, suggesting that H19 inhibition might be a potential target for the treatment of TSCC.

Thermally Strained Band Gap Engineering of Transition-Metal Dichalcogenide Bilayers with Enhanced Light-Matter Interaction toward Excellent Photodetectors.

Integration of strain engineering of two-dimensional (2D) materials in order to enhance device performance is still a challenge. Here, we successfully demonstrated the thermally strained band gap engineering of transition-metal dichalcogenide bilayers by different thermal expansion coefficients between 2D materials and patterned sapphire structures, where MoS2 bilayers were chosen as the demonstrated materials. In particular, a blue shift in the band gap of the MoS2 bilayers can be tunable, displaying an extraordinary capability to drive electrons toward the electrode under the smaller driven bias, and the results were confirmed by simulation. A model to explain the thermal strain in the MoS2 bilayers during the synthesis was proposed, which enables us to precisely predict the band gap-shifted behaviors on patterned sapphire structures with different angles. Furthermore, photodetectors with enhancement of 286% and 897% based on the strained MoS2 on cone- and pyramid-patterned sapphire substrates were demonstrated, respectively.