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Refractory multi-principal element alloys (RMPEAs) are promising materials for high-temperature structural applications. Here, we investigate the role of short-range ordering (SRO) on dislocation glide in the MoNbTi and TaNbTi RMPEAs using a multi-scale modeling approach. Monte carlo/molecular dynamics simulations with a moment tensor potential show that MoNbTi exhibits a much greater degree of SRO than TaNbTi and the local composition has a direct effect on the unstable stacking fault energies (USFEs). From mesoscale phase-field dislocation dynamics simulations, we find that increasing SRO leads to higher mean USFEs and stress required for dislocation glide. The gliding dislocations experience significant hardening due to pinning and depinning caused by random compositional fluctuations, with higher SRO decreasing the degree of USFE dispersion and hence, amount of hardening. Finally, we show how the morphology of an expanding dislocation loop is affected by the applied stress. [ABSTRACT FROM AUTHOR]

Severe lattice distortion is a prominent feature of high-entropy alloys (HEAs) considered a reason for many of those alloys' properties. Nevertheless, accurate characterizations of lattice distortion are still scarce to only cover a tiny fraction of HEA's giant composition space due to the expensive experimental or computational costs. Here we present a physics-informed statistical model to efficiently produce high-throughput lattice distortion predictions for refractory non-dilute/high-entropy alloys (RHEAs) in a 10-element composition space. The model offers improved accuracy over conventional methods for fast estimates of lattice distortion by making predictions based on physical properties of interatomic bonding rather than atomic size mismatch of pure elements. The modeling of lattice distortion also implements a predictive model for yield strengths of RHEAs validated by various sets of experimental data. Combining our previous model on intrinsic ductility, a data mining design framework is demonstrated for efficient exploration of strong and ductile single-phase RHEAs. [ABSTRACT FROM AUTHOR]

Applications of body-centered-cubic (BCC) refractory multicomponent alloys require their room-temperature ductility and high-temperature surface passivation. Using physics-informed surrogate models and thermodynamic modeling, we devised a hierarchical workflow for the initial screening of promising refractory alloys in 13-element composition space (Ti–Zr–Hf–V–Nb–Ta–Mo–W–Re–Ru–Al–Cr–Si). Screening criteria included high intrinsic ductility according to Rice model of crack-tip deformation, pure BCC phase at 800 ∘ C, and sufficient concentrations of Cr, Al or Si for surface passivation potency. 1184 Candidates were selected from 10 7 quaternary alloys. 10 Representative candidates were verified by first-principles calculations of intrinsic ductility parameters and thermodynamic modeling of oxidation capability at 900 ∘ C. [ABSTRACT FROM AUTHOR]

Chemical design of SiO2-based glasses with high elastic moduli and low weight is of great interest. However, it is difficult to find a universal expression to predict the elastic moduli according to the glass composition before synthesis since the elastic moduli are a complex function of interatomic bonds and their ordering at different length scales. Here we show that the densities and elastic moduli of SiO2-based glasses can be efficiently predicted by machine learning (ML) techniques across a complex compositional space with multiple (>10) types of additive oxides besides SiO2. Our machine learning approach relies on a training set generated by high-throughput molecular dynamic (MD) simulations, a set of elaborately constructed descriptors that bridges the empirical statistical modeling with the fundamental physics of interatomic bonding, and a statistical learning/predicting model developed by implementing least absolute shrinkage and selection operator with a gradient boost machine (GBM-LASSO). The predictions of the ML model are comprehensively compared and validated with a large amount of both simulation and experimental data. By just training with a dataset only composed of binary and ternary glass samples, our model shows very promising capabilities to predict the density and elastic moduli for k-nary SiO2-based glasses beyond the training set. As an example of its potential applications, our GBM-LASSO model was used to perform a rapid and low-cost screening of many (~105) compositions of a multicomponent glass system to construct a compositional-property database that allows for a fruitful overview on the glass density and elastic properties. [ABSTRACT FROM AUTHOR]

Our previous phase 3 trial (NCT01542931) failed to demonstrate improved survival when docetaxel, cisplatin and 5-fluorouracil (TPF) induction chemotherapy was introduced prior to surgery and postoperative radiotherapy in patients with locally advanced oral squamous cell carcinoma (OSCC). The aim of the present study was to investigate the long-term predictive value of GDF15 expression for potential personalized treatment strategies in OSCC. A total of 256 patients with stage III/IVA OSCC from our phase 3 trial were enrolled in the present study. Immunohistochemical staining against GDF15 was performed in the biopsy samples from 230/256 patients. Kaplan-Meier analysis, followed by the log-rank test, and the Cox proportional hazards model were used for outcome analysis using the statistical SPSS 18.0 software package for Windows. Among the 230 patients, low GDF15 expression was detected in 68 patients and high GDF15 expression was detected in 162 patients. With a median follow-up period of 67 months, the patients with low GDF15 expression exhibited a higher survival rate than those with high GDF15 expression, including 5-year overall survival (73.4 vs. 57.7%; P=0.059), 5-year disease-free survival (64.5 vs. 49.2%; P=0.033), 5-year locoregional recurrence-free survival (66.0 vs. 51.5%; P=0.043) and 5-year distant metastasis-free survival (73.4 vs. 56.6%; P=0.038) rates. Furthermore, the cT3/4N0M0 patients with high GDF15 expression benefited significantly from TPF induction chemotherapy, including overall survival (HR=0.233; P=0.02), disease-free survival (HR=0.296; P=0.014), locoregional recurrence-free survival (HR=0.347; P=0.035) and distant metastasis-free survival (HR=0.212; P=0.013) rates. The results of the present study suggested that elevated GDF15 expression may be used as a long-term prognostic biomarker for poor clinical outcomes in patients with locally advanced OSCC. Elevated GDF15 expression in cT3/4N0M0 patients predicts significant long-term benefit of survival from TPF induction chemotherapy. [ABSTRACT FROM AUTHOR]

Systematic first-principles calculations were performed to study the lattice dynamics of Yb14MnSb11 and hence to obtain a wide range of its thermodynamic properties at high temperatures. The calculated results were analyzed in terms of the lattice contribution and the electronic contribution, together with a comparison with a collection of experimental thermochemical data. At 0 K, the electronic density of states showed the typical feature of a p-type semiconductor—a small amount of unoccupied electronic states exclusively made of the major spin by a range of ∼0.6 eV above the Fermi energy. It showed that the Mn atom had a ferromagnetic spin moment of ∼4 μB. As a semiconductor, it was found that the electronic contribution to the heat capacity was substantial, with an electronic heat capacity coefficient of ∼0.0006 J/mole-atom/K2. [ABSTRACT FROM AUTHOR]

PURPOSE: To evaluate the effect of decompression for large mandibular odontogenic keratocystic tumours in adolescents. METHODS: Fifteen cases of large odontogenic keratocystic tumours in mandible underwent decompression from Feb.2005 to Feb. 2011, the average age of the patients was 19.3 years. Patients were follow-up by X-ray every 2-3 months, and every 6-12 months by CT. Subsequent curettage was given when the remaining tumours were less than 2cm in diameter. RESULTS: The decompression period lasted from 12 to 18 months, with an average time of 13.6 months. After decompression, bone regeneration was noticed on radiographs, the average decrement percentage of the tumour size was 41.5% at 6-month, 61.5% at 12-month and 81.8% at 18-month after operation. All patients were followed up for 1-5 years after secondary surgical curettage, no recurrence was observed. CONCLUSION: Decompression is a preferred treatment for large mandibular odontogenic keratocystic tumours in adolescents. [ABSTRACT FROM AUTHOR]

PURPOSE: To investigate the proportion of salivary gland tumors in the elder patients in the past ten years, in order to provide reference for clinical diagnosis and treatment. METHODS: The medical data of salivary gland tumors treated in our department from January 2000 to December 2009 were reviewed and analyzed. The changes of three periods between 21cl0s, 20c90s and 20c80s were compared. RESULTS: The number of salivary gland tumors in elder patients increased rapidly in recent years, especially that of benign tumors. Warthin's tumor was the most common benign tumors, and adenoid cystic carcinoma was most often found in malignant tumors. Carcinoma ex pleomorphic adenoma rose to the third among malignant tumors of salivary gland and first among parotid gland malignancies. The proportion of benign tumor was almost equal to malignant tumor in minor salivary gland. The benign-malignant ratio of palatal salivary gland was 1.34:1, which was opposite to the previous figure. The parotid gland was the most common site, followed by palatal and submandibular gland. CONCLUSIONS: The proportion of salivary gland tumors in elder patients in 2000s was different from that in 1980s and 1990s. The changes should be taken into attention in daily clinical works. [ABSTRACT FROM AUTHOR]

It's uncommon for lipoma growing beneath the mucusa of the floor of mouth. A case of lipoma in the floor of mouth was reported. The clinical feature and key points of treatment were discussed based on literature review. [ABSTRACT FROM AUTHOR]

PURPOSE: To analyse the clinical features and treatment of ectopic meningioma (EM) in oral and maxillofacial region. METHODS: Twenty-three cases of EM in the oral and maxillofacial region from 1990 to 2008 were reviewed. The clinical features, image findings, surgical treatment and follow-up results were analyzed. RESULTS: The median age of these patients was 37 years old and there was no gender predilection, but there were more female patients in the group of over 40 years old. The primary sites of the tumor were parapharyngeal space (13), infratemporal space/ pterygopalatine space(5), temporal region(3),orbital area (1) and buccal mucosa(l). The CT image of EM in the oral and maxillofacial region was similar to that in the brain. All 23 cases underwent surgical treatment, seventeen cases underwent the tumor totally resected and 6 cases underwent partially resected. Twelve cases were followed up, in which 3 cases recurred and 8 cases had a long-term nerve injury. CONCLUSIONS: EM in the oral and maxillofacial region mainly occurs in adolescent, middle-aged patients and females over 40 years old. The predilection site of the tumor is the deep space of oral and maxillofacial region with adherence to the cervical sheath and lower cranial nerves. Preoperative CT scan is helpful for diagnosis. The main choice of treatment is total resection. The main complication is nerve injury. Supported by Research Fund of Science and Technology Commission of Shanghai Municipality (Grant No. 08DZ2271100). [ABSTRACT FROM AUTHOR]

To investigate the clinical manifestation of branchial cleft cyst (fistula) and provide some clinical experience on its diagnosis and treatment. METHODS: From June 1993 to December 2006, two hundred and eighty-four patients with branchial cleft cyst or fistula underwent surgical treatment were retrospectively reviewed, the preoperative examinations, preoperative diagnosis and postoperative pathological diagnosis were recorded, and the data was analyzed with SAS6.12 software package. RESULTS: Among the 284 patients with branchial cleft cyst of fistula confirmed by postoperative pathological diagnosis, there were 132 patients (46.5%) with first branchial cleft cyst or fistula, one hundred and forty-five patients (51.1%) with second branchial cleft cyst or fistula, and 7 patients (2.4%) with third branchial cleft cyst of fistula. First branchial cleft cyst or fistula often occurred in patients older than 40 years, second and third branchial cleft cyst or fistula often occurred in patients younger than 40 years. The pathological diagnosis confirmed 188 primary lesions, thirty-three recurrent lesions, forty-four lesions with internal fistula, fourteen lesions with secondary infection and external fistula, and three lesions with both internal and external fistulae. One patient was found with tuberculosis simultaneously, two patients with multiple cysts, one patient with venous malformation. Six lesions were found malignant, five from first branchial cleft and one from second brancial cleft. The highest accuracy of preoperative diagnosis was 66.20% using ultrasonography. During the follow-up period, 5.98% of patients had recurrence. CONCLUSIONS: First and second branchial cleft cysts (fistula) are the most common lesions. Preoperative ultrasonography is the first choice for diagnosis of branchial cleft cyst (fistula). Complete resection including the cyst and fistula is the key to successful surgical treatment. [ABSTRACT FROM AUTHOR]

PURPOSE: This study aims to investigate the correlation between the thickness of the tongue carcinoma and cervical lymph node metastasis obtained with ultrasonography. METHODS: The tumor thickness of 37 primary tongue cancers were measured in the sonogram by the intraoral ultrasonography. The cervical lymph nodes were scanned, and the number, size, internal echo, and blood stream were measured to evaluate the nature. SAS6.1 software package was used for Chi-square test, non-parametric test and Logistic regression. RESULTS: The tumor thickness measured before operation with ultrasonngraphy and after operation from pathological sections was subjected to non-parameter Wilcox rank-sum test. P=0.2013, indicating that there was no significant difference between the mean thickness obtained from the two modalities. The tumor thickness and cervical lymph node metastasis were subjected to non-parameter rank correlation test, the Spearman r=0.6824,P<0.01, indicating that there were a positive correlation between the tumor thickness measured by ultrasonography scan and cervical lymph node metastasis. Logistic regression analysis also showed that the risk of metastasis of the neck lymph nodes increased with the increased thickness of the tumors. CONCLUSIONS: The accuracy and sensitiveness of ultrasonography in measuring the tumor thickness and detection of cervical lymph metastases make it a promising pre-operative tool in staging the cancer and optimizing the treatment plan for the surgeons. [ABSTRACT FROM AUTHOR]

PURPOSE: This study aims to investigate the correlation between the thickness of the tongue carcinoma and cervical lymph node metastasis obtained with ultrasonography. METHODS: The tumor thickness of 37 primary tongue cancers were measured in the sonogram by the intraoral ultrasonography. The cervical lymph nodes were scanned, and the number, size, internal echo, and blood stream were measured to evaluate the nature. SAS6.1 software package was used for Chi-square test, non-parametric test and Logistic regression. RESULTS: The tumor thickness measured before operation with ultrasonography and after operation from pathological sections was subjected to non-parameter Wilcox rank-sum test, P=0.2013, indicating that there was no significant difference between the mean thickness obtained from the two modalities. The tremor thickness and cervical lymph node metastasis were subjected to non-parameter rank correlation test, the Spearman r=0.6824,P<0.01, indicating that there were a positive correlation between the tumor thickness measured by ultrasonography scan and cervical lymph node metastasis. Logistic regression analysis also showed that the risk of metastasis of the neck lymph nodes increased with the increased thickness of the tumors. CONCLUSIONS: The accuracy and sensitiveness of ultrasonography in measuring the tumor thickness and detection of cervical lymph metastases make it a promising pre-operative tool in staging the cancer and optimizing the treatment plan for the surgeons. [ABSTRACT FROM AUTHOR]

PURPOSE: To investigate the clinical manifestation of branchial cleft cyst (fistula) and provide some clinical experience on its diagnosis and treatment. METHODS: From June 1993 to December 2006, two hundred and eighty-four patients with branchial cleft cyst or fistula underwent surgical treatment were retrospectively reviewed, the preoperative examinations, preoperative diagnosis and postoperative pathological diagnosis were recorded, and the data was analyzed with SAS6.12 software package. RESULTS: Among the 284 patients with branchial cleft cyst or fistula confirmed by postoperative pathological diagnosis, there were 132 patients (46.5%) with first branchial cleft cyst or fistula, one hundred and forty-five patients (51.1%) with second branchial cleft cyst or fistula, and 7 patients (2.4%) with third branchial cleft cyst or fistula. First branchial cleft cyst or fistula often occurred in patients older than 40 years, second and third branchial cleft cyst or fistula often occurred in patients younger than 40 years. The pathological diagnosis confirmed 188 primary lesions, thirty-three recurrent lesions, forty-four lesions with internal fistula, fourteen lesions with secondary infection and external fistula, and three lesions with both internal and external fistulae. One patient was found with tuberculosis simultaneously, two patients with multiple cysts, one patient with venous malformation. Six lesions were found malignant, five from first branchial cleft and one from second branchial cleft. The highest accuracy of preoperative diagnosis was 66.20% using ultrasonography. During the follow-up period, 5.98% of patients had recurrence. CONCLUSIONS: First and second branchial cleft cysts (fistula) are the most common lesions. Preoperative ultrasonography is the first choice for diagnosis of branchial cleft cyst (fistula). Complete resection including the cyst and fistula is the key to successful surgical treatment. [ABSTRACT FROM AUTHOR]

PURPOSE: To evaluate the application of autologous bone fresh-frozen and re-implantation in treatment of cranio-maxillofacial bone tumors. METHODS: Four cases with cranio-maxillofacial bone tumors, including one in the frontal bone and three in the mandible, underwent osteoectomy, autologous diseased bone fresh-frozen by nitrogen, reimplantation of the bone and internal fixation by titanium plate to treat the bone tumor and reconstruct the bone defect. RESULTS: All four cases had one-stage healing 10-14 days after operation. One patient had pathological bone fracture 2 months postoperatively, the other three patients were well-cured without tumor recurrence and gained satisfied cosmetic appearance during 6 months to 3 years of follow-up. The X-ray films showed that the frozen bone was substituted by new bone formation. CONCLUSIONS: Autologous bone fresh-frozen and re-implantation is a feasible method in cranio-maxillofacial bone tumor treatment, especially for young patients. It make possible to do radical surgery and reconstruct the bone defect simultaneously, and is thus worthy of clinical application. [ABSTRACT FROM AUTHOR]

PURPOSE: To evaluate the application of autologous bone fresh-frozen and re-implantation in treatment of cranio-maxillofacial bone tumors. METHODS: Four cases with cranio-maxillofacial bone tumors, including one in the frontal bone and three in the mandible, underwent osteoectomy, autologous diseased bone fresh-frozen by nitrogen, re-implantation of the bone and internal fixation by titanium plate to treat the bone tumor and reconstruct the bone defect. RESULTS: All four cases had one-stage healing 10-14 days after operation. One patient had pathological bone fracture 2 months postoperatively, the other three patients were well-cured without tumor recurrence and gained satisfied cosmetic appearance during 6 months to 3 years of follow-up. The X-ray films showed that the frozen bone was substituted by new bone formation. CONCLUSIONS: Autologous bone fresh-frozen and re-implantation is a feasible method in cranio-maxillofacial bone tumor treatment, especially for young patients. It make possible to do radical surgery and reconstruct the bone defect simultaneously, and is thus worthy of clinical application. [ABSTRACT FROM AUTHOR]

The interactions between solute atoms and crystalline defects such as vacancies, dislocations, and grain boundaries are essential in determining alloy properties. Here we present a general linear correlation between two descriptors of local electronic structures and the solute-defect interaction energies in binary alloys of body-centered-cubic (bcc) refractory metals (such as W and Ta) with transition-metal substitutional solutes. One electronic descriptor is the bimodality of the d-orbital local density of states for a matrix atom at the substitutional site, and the other is related to the hybridization strength between the valance sp- and d-bands for the same matrix atom. For a particular pair of solute-matrix elements, this linear correlation is valid independent of types of defects and the locations of substitutional sites. These results provide the possibility to apply local electronic descriptors for quantitative and efficient predictions on the solute-defect interactions and defect properties in alloys. Understanding the interactions between solute atoms and crystalline defects is essential for determining alloy properties. Here the authors use a linear regression model to propose a quantitative correlation between local electronic structure descriptors and the solute-defect interaction energies in bcc refractory alloys. [ABSTRACT FROM AUTHOR]

Atomic disordering in materials alters their physical and chemical properties and can subsequently affect their performance. In complex ceramic materials, it is a challenge to understand the nature of structural disordering, due to the difficulty of direct, atomic-scale experimental observations. Here we report the direct imaging of ion irradiation-induced antisite defects in Mn+1AXn phases using double CS-corrected scanning transmission electron microscopy and provide compelling evidence of order-to-disorder phase transformations, overturning the conventional view that irradiation causes phase decomposition to binary fcc-structured Mn+1Xn. With the formation of uniformly distributed cation antisite defects and the rearrangement of X anions, disordered solid solution γ-(Mn+1A)Xn phases are formed at low ion fluences, followed by gradual transitions to solid solution fcc-structured (Mn+1A)Xn phases. This study provides a comprehensive understanding of the order-to-disorder transformations in Mn+1AXn phases and proposes a method for the synthesis of new solid solution (Mn+1A)Xn phases by tailoring the disorder. Highly ordered and compositionally complex ceramics are prone to disordering under irradiation, but exactly how is unclear. Here, the authors use high resolution microscopy to directly image the order-to-disorder phase transformations in Ti3AlC2 into otherwise unattainable solid solutions. [ABSTRACT FROM AUTHOR]

Creating and maintaining precipitates coherent with the host matrix, under service conditions is one of the most effective approaches for successful development of alloys for high temperature applications; prominent examples include Ni- and Co-based superalloys and Al alloys. While ferritic alloys are among the most important structural engineering alloys in our society, no reliable coherent precipitates stable at high temperatures have been found for these alloys. Here we report discovery of a new, nano-sized superlattice (NSS) phase in ball-milled Fe alloys, which maintains coherency with the BCC matrix up to at least 913 °C. Different from other precipitates in ferritic alloys, this NSS phase is created by oxygen-ordering in the BCC Fe matrix. It is proposed that this phase has a chemistry of Fe3O and a D03 crystal structure and becomes more stable with the addition of Zr. These nano-sized coherent precipitates effectively double the strength of the BCC matrix above that provided by grain size reduction alone. This discovery provides a new opportunity for developing high-strength ferritic alloys for high temperature applications. [ABSTRACT FROM AUTHOR]