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.

Direct evidence of interaction-induced Dirac cones in a monolayer silicene/Ag(111) system.

Silicene, analogous to graphene, is a one-atom-thick 2D crystal of silicon, which is expected to share many of the remarkable properties of graphene. The buckled honeycomb structure of silicene, along with enhanced spin-orbit coupling, endows silicene with considerable advantages over graphene in that the spin-split states in silicene are tunable with external fields. Although the low-energy Dirac cone states lie at the heart of all novel quantum phenomena in a pristine sheet of silicene, a hotly debated question is whether these key states can survive when silicene is grown or supported on a substrate. Here we report our direct observation of Dirac cones in monolayer silicene grown on a Ag(111) substrate. By performing angle-resolved photoemission measurements on silicene(3 × 3)/Ag(111), we reveal the presence of six pairs of Dirac cones located on the edges of the first Brillouin zone of Ag(111), which is in sharp contrast to the expected six Dirac cones centered at the K points of the primary silicene(1 × 1) Brillouin zone. Our analysis shows clearly that the unusual Dirac cone structure we have observed is not tied to pristine silicene alone but originates from the combined effects of silicene(3 × 3) and the Ag(111) substrate. Our study thus identifies the case of a unique type of Dirac cone generated through the interaction of two different constituents. The observation of Dirac cones in silicene/Ag(111) opens a unique materials platform for investigating unusual quantum phenomena and for applications based on 2D silicon systems.

Craniofacial Resection and Reconstruction in Patients With Recurrent Cancer Involving the Craniomaxillofacial Region.

PURPOSE: Head and neck tumors that involve the craniomaxillofacial region are classified as stage IVb disease and are clinically challenging. In this study, the outcomes of craniofacial resection and craniofacial reconstruction in patients with recurrent malignant tumors involving the craniomaxillofacial region were evaluated. PATIENTS AND METHODS: This retrospective observational study was conducted from January 2008 to August 2015. Data collected for each patient included age, gender, tumor site, initial treatment, craniofacial resection, reconstruction flaps and complications after craniofacial resection, adjuvant treatment, and reported outcomes of craniofacial resection and craniofacial reconstruction. The χ2 test in SPSS was used to analyze the data. RESULTS: Twenty-four patients with recurrent malignant tumors involving the craniomaxillofacial region were identified who had undergone craniofacial resection at the Center of Craniomaxillofacial Surgery of Sun Yat-sen University (Guangzhou, Guangdong, China). The study population was comprised of 24 patients (15 men and 9 women; age range, 21 to 73 yr) with recurrent tumors (58.3% with squamous cell carcinoma [SCC], 41.7% with sarcoma [SA]) involving the craniomaxillofacial region who underwent craniofacial resection. Craniofacial resection consisted of orbital exenteration and maxillotomy; anterior skull base surgery, facial resection, and mandibulotomy; or ipsilateral radical neck dissection. The resultant craniomaxillofacial defects were reconstructed using extended vertical lower trapezius island myocutaneous flaps (TIMFs), temporalis myofascial flaps, or submental flaps. All patients with recurrent malignant tumor involving the craniomaxillofacial region underwent gross total resection of the tumor; 22 patients underwent craniofacial reconstruction. There were no major surgical complications. Minor flap failure and wound dehiscence in the donor site occurred in 4 patients. The follow-up period ranged from 8 to 36 months. Seven patients in the SCC group and 7 in the SA group were alive with no evidence of disease (AND), 3 in the SCC group and 2 in the SA group were alive with disease (AWD), and 4 in the SCC and 1 in the SA group died of the disease (DOD) after local recurrence or distant metastases at 8 to 18 months. There were no statistical differences among the AND, AWD, and DOD groups. CONCLUSIONS: Craniofacial resection remains an effective salvage treatment for patients with recurrent SCC and SA involving the craniomaxillofacial region. The extended vertical lower TIMF is a large, simple, and reliable flap for reconstructing major defects after a craniofacial resection.

Endoscopy-Assisted Transoral Versus Endoscopy-Assisted Transcervical Minimal Incision Plus Mandibular Osteotomy Approach in Resection of Large Parapharyngeal Space Tumors.

BACKGROUND: Resection of the parapharyngeal space is often challenging. This study aims to evaluate the outcome of the endoscopy-assisted transoral approach for resection of the parapharyngeal space tumors compared with the endoscopy-assisted transcervical approach. METHODS: Twenty-three consecutive patients (15 males, 8 females) who underwent resection of large parapharyngeal space tumors via endoscopy-assisted transoral (ETO) approach or endoscopy-assisted transcervical minimal incision plus osteotomy of the vertical ramus outside the mandibular foramen (ETC + MO) approach were analyzed retrospectively. RESULTS: The tumors in ETO group are benign; there are 2 patients with adenoid cystic carcinoma and 1 patient with recurrent pleomorphic adenoma in ETC + MO group. All of the tumors were removed completely and without rupture. No major complications developed in any patient. Temporary facial paresis occurred in 1 patient in the ETC + MO group, which resolved spontaneously within 8 weeks. The cosmetic effects of all patients in ETO groups and 10 patients in ETC + MO groups were excellent. Patients were followed up for 7 to 26 months, no recurrence was encountered. CONCLUSION: ETO and ETC + MO approach in resection of large parapharyngeal space tumors are feasible and safe technique that achieve excellent aesthetic and functional results. Endoscopy-assisted transoral approach can shorten hospitalized time and avoid the risk of marginal mandibular nerve injury and ETC + MO approach may be used in malignant or recurrent parapharyngeal space tumors.

Dysphagia in Tongue Cancer Patients Before and After Surgery.

PURPOSE: To define factors influencing postoperative aspiration in tongue cancer patients and to analyze the characteristics of dysphagia before and after surgery. MATERIALS AND METHODS: A total of 112 tongue cancer patients participated in this work. Videofluoroscopic swallowing studies were performed in all patients before and after surgery. A Penetration-Aspiration Scale score of 3 or greater was defined as an aspiration risk. Qualitative data were collected on a frame-by-frame basis from each videofluoroscopic swallowing study and analyzed. RESULTS: Smoking (58.14%, P < .01), tongue resection greater than 50% (38.71%, P < .05), and advanced tumor stage (49.18%, P < .01) were strong risk factors for aspiration. High incidences of inadequate tongue movement, delayed oral transit time, reduced hyoid bone elevation, poor aspiration or penetration, vallecula epiglottica, and residual material in the pyriform sinuses were evident after surgery (all P < .001). The Penetration-Aspiration Scale score was significantly higher after surgery than before surgery. The incidence of silent aspiration increased to 6.25% postoperatively. CONCLUSIONS: Smoking, larger tongue resection, and advanced tumor stage were strong risk factors for postoperative aspiration and dysphagia complications in tongue cancer patients. The aspiration rate was higher after surgery. Further studies should focus on the prevention and early treatment of dysphagia, especially postoperative aspiration, in tongue cancer patients.

Robust Large Gap Two-Dimensional Topological Insulators in Hydrogenated III-V Buckled Honeycombs.

A large gap two-dimensional (2D) topological insulator (TI), also known as a quantum spin Hall (QSH) insulator, is highly desirable for low-power-consuming electronic devices owing to its spin-polarized backscattering-free edge conducting channels. Although many freestanding films have been predicted to harbor the QSH phase, band topology of a film can be modified substantially when it is placed or grown on a substrate, making the materials realization of a 2D TI challenging. Here we report a first-principles study of possible QSH phases in 75 binary combinations of group III (B, Al, Ga, In, and Tl) and group V (N, P, As, Sb, and Bi) elements in the 2D buckled honeycomb structure, including hydrogenation on one or both sides of the films to simulate substrate effects. A total of six compounds (GaBi, InBi, TlBi, TlAs, TlSb, and TlN) are identified to be nontrivial in unhydrogenated case; whereas for hydrogenated case, only four (GaBi, InBi, TlBi, and TlSb) remains nontrivial. The band gap is found to be as large as 855 meV for the hydrogenated TlBi film, making this class of III-V materials suitable for room temperature applications. TlBi remains topologically nontrivial with a large band gap at various hydrogen coverages, indicating the robustness of its band topology against bonding effects of substrates.

Prediction of large-gap two-dimensional topological insulators consisting of bilayers of group III elements with Bi.

We use first-principles electronic structure calculations to predict a new class of two-dimensional (2D) topological insulators (TIs) in binary compositions of group III elements (B, Al, Ga, In, and Tl) and bismuth (Bi) in a buckled honeycomb structure. We identify band inversions in pristine GaBi, InBi, and TlBi bilayers, with gaps as large as 560 meV, making these materials suitable for room-temperature applications. Furthermore, we demonstrate the possibility of strain engineering in that the topological phase transition in BBi and AlBi could be driven at ∼6.6% strain. The buckled structure allows the formation of two different topological edge states in the zigzag and armchair edges. More importantly, isolated Dirac-cone edge states are predicted for armchair edges with the Dirac point lying in the middle of the 2D bulk gap. A room-temperature bulk band gap and an isolated Dirac cone allow these states to reach the long-sought topological spin-transport regime. Our findings suggest that the buckled honeycomb structure is a versatile platform for hosting nontrivial topological states and spin-polarized Dirac fermions with the flexibility of chemical and mechanical tunability.

Preliminary experiences in treating infantile hemangioma with propranolol.

The aim of this study was to evaluate the outcome of treating infantile hemangioma with the use of oral propranolol. A total of 27 patients with hemangiomas were treated with oral propranolol therapy. The subjects included 21 female patients and 6 male patients whose age ranged between 3 weeks and 7 months. Locations of lesions were as follows: 22 on the face and neck, 3 on the trunk, and 2 on the limbs. The dose of 0.5 mg/kg/d of propranolol was administered; and was gradually doubled to a maximum of 2 mg/kg/d. The treatment lasted for a period of 2.75 to 5.75 months without major complications. Two days later, a change in color was observed in 100% of patients, and 2 weeks later >75% reduction in diameter of the original lesion was found in 25.9% of patients. Treating infantile hemangioma with the use of oral propranolol is effective and reliable.

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.

Reconstruction of major full cheek defects with combined extensive pedicled supraclavicular fasciocutaneous island flaps and extended vertical lower trapezius island myocutaneous flaps after ablation of advanced oral cancer.

PURPOSE: The present clinical study assessed the feasibility of extensive pedicled supraclavicular fasciocutaneous island flaps combined with extended vertical lower trapezius island myocutaneous flaps for large, full-thickness cheek defect reconstruction after ablative oral cancer surgery. PATIENTS AND METHODS: A retrospective review of data from consecutive patients requiring extensive pedicled supraclavicular fasciocutaneous island flaps and the extended vertical lower trapezius island myocutaneous flap to provide both an inner and an outer lining for major full-thickness cheek defects after oncologic resection. RESULTS: Eight patients had advanced oral squamous cell carcinoma. All patients had combined bone and extensive soft-tissue defects. The extensive pedicled supraclavicular fasciocutaneous island flap with a skin paddle measuring 10 × 8 cm to 14 × 10 cm and the extended vertical lower trapezius island myocutaneous flap with a skin paddle measuring 25 × 10 cm to 15 × 8 cm were used to reconstruct the major through-and-through defects. No major complications occurred in any patient. The patients were followed up for 6 to 20 months; 6 patients were living with no evidence of disease, 1 was living with disease, and 1 had died of local recurrence. CONCLUSIONS: The combined use of the extensive pedicled supraclavicular fasciocutaneous island flap with an extended vertical lower trapezius island myocutaneous flap to reconstruct major through-and-through cheek soft defects is reliable and an excellent alternative to other pedicles, even microsurgical free flaps, for patients who have previously undergone radiotherapy and surgery of the head and neck.

Posttraumatic stress disorder of Red Cross nurses in the aftermath of the 2008 Wenchuan China Earthquake.

This study investigated the symptoms, psychological distress characteristics, and related factors in China Red Cross disaster relief nurses following the 2008 Wenchuan Earthquake in China that began on May 12 and lasted to June 23, 2008. A sample of 210 exposed nurses and a reference group of 236 nonexposed Red Cross nurses were surveyed within 1 year after the catastrophic earthquake. They were given a self-report questionnaire to assess demographics, posttraumatic stress disorder, and depression symptoms. Exposed nurses reported higher psychological distress on all aspects than nonexposed nurses. Scores on the Traumatic Stress Symptom Checklist were predicted by the avoidance of traumatic thoughts during the earthquake, personality traits, prior disaster experience, and preexisting stress, and other background factors were associated with scores on measures of psychological distress in exposed nurses. The conclusion indicated that disaster relief nurses experienced psychological distress and that immediate psychological intervention should be initiated.

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.

Structural and electronic properties of hydrogen adsorptions on BC3 sheet and graphene: a comparative study.

We have systematically investigated the effect of hydrogen adsorption on a single BC3 sheet as well as graphene using first-principles calculations. Specifically, a comparative study of the energetically favorable atomic configurations for both H-adsorbed BC3 sheets and graphene at different hydrogen concentrations ranging from 1/32 to 4/32 ML and 1/8 to 1 ML was undertaken. The preferred hydrogen arrangement on the single BC3 sheet and graphene was found to have the same property as that of the adsorbed H atoms on the neighboring C atoms on the opposite sides of the sheet. Moreover, at low coverage of H, the pattern of hydrogen adsorption on the BC3 shows a proclivity toward formation on the same ring, contrasting their behavior on graphene where they tend to form the elongated zigzag chains instead. Lastly, both the hydrogenated BC3 sheet and graphene exhibit alternation of semiconducting and metallic properties as the H concentration is increased. These results suggest the possibility of manipulating the bandgaps in a single BC3 sheet and graphene by controlling the H concentrations on the BC3 sheet and graphene.

Electronic structures of an epitaxial graphene monolayer on SiC(0001) after gold intercalation: a first-principles study.

The atomic and electronic structures of an Au-intercalated graphene monolayer on the SiC(0001) surface were investigated using first-principles calculations. The unique Dirac cone of graphene near the K point reappeared as the monolayer was intercalated by Au atoms. Coherent interfaces were used to study the mismatch and the strain at the boundaries. Our calculations showed that the strain at the graphene/Au and Au/SiC(0001) interfaces also played a key role in the electronic structures. Furthermore, we found that at an Au coverage of 3/8 ML, Au intercalation leads to a strong n-type doping of graphene. At 9/8 ML, it exhibited a weak p-type doping, indicative that graphene was not fully decoupled from the substrate. The shift in the Dirac point resulting from the electronic doping was not only due to the different electronegativities but also due to the strain at the interfaces. Our calculated positions of the Dirac points are consistent with those observed in the ARPES experiment (Gierz et al 2010 Phys. Rev. B 81 235408).

Association of clinicopathologic parameters with the expression of inducible nitric oxide synthase and vascular endothelial growth factor in mucoepidermoid carcinoma.

BACKGROUND: The roles that inducible nitric oxide synthase (iNOS) and vascular endothelial growth factor (VEGF) play in tumorigenesis have been given special attention. In many tumors, their expression is upregulated. In addition, iNOS can stimulate the expression of VEGF. This study was carried out to investigate the expression of iNOS and VEGF as well as their relationship with angiogenesis and the clinicopathological characteristics of mucoepidermoid carcinoma (MEC). METHOD: The expression of iNOS and VEGF was detected by Streptavidin-peroxidase immunohistochemistry, and microvessel density (MVD) was determined by anti-CD34 antibody staining in 70 MEC cases and 40 normal salivary gland tissues (NSG). Follow-up was performed on the 70 patients with MEC. Non-parametric tests were performed for the comparison of iNOS and VEGF expression. RESULTS: The positive expression rates of iNOS and VEGF were successively enhanced in NSG, well-differentiated and poorly differentiated MEC (P < 0.05). MVD counts were positively correlated with the expression levels of iNOS and VEGF in MEC (P < 0.05). The expression of iNOS was positively correlated with the expression of VEGF (P < 0.05). iNOS and VEGF expression were significantly associated with tumor differentiation, size metastasis, and relapse (P < 0.05) but were not correlated lymph node metastasis and metastasis. CONCLUSION: Inducible nitric oxide synthase can stimulate the expression of VEGF, and their expression status may help assess tumor malignancy and patient prognosis.

IMP3 is a novel biomarker to predict metastasis and prognosis of tongue squamous cell carcinoma.

Insulinlike growth factor II mRNA-binding protein 3 (IMP3) is a newly identified mRNA-binding protein that is involved in embryogenesis and carcinogenesis of some malignant tumors. The aim of this study was to investigate the clinicopathologic significance of this protein in tongue squamous cell carcinoma (SCC). The expression of IMP3 in 65 samples of tongue SCC and 27 cases of oral leukoplakia (OL) was evaluated by immunohistochemistry. These expression levels were correlated with clinical and pathologic features as well as death from tongue SCC. Weak immunohistochemical stain for IMP3 was identified in all 19 cases of OL with mild dysplasia, and no immunohistochemical reactivity was found in 8 cases of OL without dysplasia. Positive immunohistochemical stain for IMP3 was identified in 50 cases (77%) of SCC; among them, weak staining was identified in 33 cases (51%) and intermediate staining in 17 cases (26%). To compare the expression of IMP3 in tongue SCC and OL, stronger immunohistochemical reactivity was found in tongue SCC (P < 0.05). Stronger expression of IMP3 was found to be associated with lymphoid metastasis (P < 0.05) and patient poor outcome (median survival time of 40 months in the negative and weak expression group vs 10 months in the intermediate expression group; P < 0.05). This study suggests that the increase in IMP3 expression in tongue leukopathia and SCCs may play a role in the carcinogenesis and tumor metastasis of tongue SCCs. Insulinlike growth factor II mRNA-binding protein 3 could be a novel prognostic indicator for patients with tongue SCCs.

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.

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.