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Three kinds of metal atoms with different valence electronic configurations, Bi (6s26p3), Y (4d15s2), and Ce (4f15d16s2), were selected to investigate the effect of A-site (La3+) doping on electronic band structure, photoelectric properties, and photocatalytic performance of LaFeO3 perovskite. It was identified that the Bi doped LaFeO3 presented significantly improved photocatalytic activity towards the reduction of CO2, while the Y or Ce doped LaFeO3 displayed decreased photocatalytic activity compared to the pristine LaFeO3. It was revealed that doping of all the three metal atoms resulted in narrowed band gap and thus extended light absorption of LaFeO3 by lowering its conduction band minimum (CBM). The recombination rate and mobility of the charge carriers were represented by the relative effective mass (D) between holes and electrons for pristine and A-site doped LaFeO3. The doping of Bi resulted in increased D value, attributed to the Bi 6s electron states at the valence band maximum (VBM), and thus promoted separation and transfer of the charge carriers and improved photocatalytic activity of LaFeO3. In contrast, the doping of Ce resulted in significantly decreased D value, induced by the highly localized Ce 4f hole states at the CBM, and thus higher recombination rate of the charge carriers and decreased photocatalytic activity of LaFeO3. Furthermore, the Y doped LaFeO3 with a slightly decreased D value presented slightly increased recombination rate of the charge carriers and thus decreased photocatalytic activity. Such a work provides new insights into the A-site doping in LaFeO3 perovskite, which should be helpful for optimizing the electronic band structure and activity of perovskite-type photocatalysts at atomic level. [ABSTRACT FROM AUTHOR]

The current research of Charpy impact mainly focuses on obtaining the ductile brittle transition temperature of materials by experiments. Compared with experiments, numerical simulation can study many problems with harsh conditions. However, there are still few studies on the influence of geometric factors such as side grooves. In this paper, the geometry of standard Charpy impact test is designed. Specimens with different widths and side grooves are tested. The finite element model of Charpy impact was established by ABAQUS software. Use test results and simulation results to verify each other. The effects of sample width, side groove depth and side groove bottom fillet on the impact fracture resistance of the sample were studied. The results show that the specimen width is positively correlated with the impact toughness of the specimen. The side groove greatly reduces the impact toughness of the material; the toughness of side groove decreases with the increase of depth; the fracture toughness of side groove decreases with the increase of fillet at the bottom of side groove. The proportion of toughness energy to impact energy of samples was analyzed. The results show that the toughness energy accounts for about 70% of the impact energy of the sample, which has little to do with the geometric characteristics of the sample. This study presents a reliable method for studying Charpy impact tests. The influence of geometric parameters is obtained, which provides a reference method for the study of impact toughness of high toughness materials. [ABSTRACT FROM AUTHOR]

Corona textures, characterized by specific mineral assemblages as layers between existing phases, are frequently observed in high-grade metamorphic rocks. The mechanisms of corona formation have been extensively investigated, however direct dating of corona phases has rarely to be attempted. In order to decipher the timing and duration of corona formation and its implications for metamorphic processes, an integrated garnet Lu–Hf and Sm–Nd and zircon U–Pb petrochronological study was conducted on a corona-bearing granulite from the Miyun region in the North China Craton. The Miyun region, located at the joint area of the Archean Eastern Block and the Paleoproterozoic Trans-North China Orogen, offers a distinctive opportunity to study polymetamorphic processes within the North China Craton. The sample shows a corona texture, primarily composed of garnet, minor clinopyroxene and quartz, that formed at the boundary between plagioclase and orthopyroxene. Pseudosection modelling for the effective bulk composition of reactive domains and conventional thermobarometric calculations indicate that the anhydrous corona assemblage (comprising clinopyroxene, garnet and quartz) formed at ~ 0.9 GPa and ~ 740 ℃. The subsequent hydrous retrogression took place at ~ 0.5 GPa and ~ 670 ℃ and led to the growth of amphibole and biotite. A Lu–Hf garnet date of 1864 ± 3 Ma is significantly younger than the U–Pb date of ca. 2454 Ma for metamorphic zircons in the sample, consistent with the disequilibrium partitioning of rare earth elements between the two phases. The well-preserved Lu zoning in garnet supports the interpretation that the Lu–Hf date represents the age of garnet growth and approximates the timing of formation of the anhydrous corona assemblage. Thus, the U–Pb age reflects a distinct Archean metamorphic event that has been widely documented in high-grade rocks across the Eastern Block of the North China Craton. The garnet Sm–Nd date of 1817 ± 6 Ma is indistinguishable from an amphibole-biotite Lu–Hf date of 1819 ± 16 Ma and ~ 47 Myr younger than the corresponding garnet Lu–Hf date. The younger Sm–Nd age represents the timing of cooling and post-dates retrogression. The Paleoproterozoic and Archean ages in the Miyun granulite align with the major tectonic events in the Trans-North China Orogen and the Eastern Block, respectively. This consistency suggests that the Miyun region likely experienced concurrent metamorphic events in both the Trans-North China Orogen and the Eastern Block. This texture-based Lu–Hf and Sm–Nd dating approach has wide applicability for rocks with explicit textures, facilitating precise extraction of temporal intervals in the metamorphic process. [ABSTRACT FROM AUTHOR]

The purpose of this study is to assess the relative clinical efficacy of treating malignant hilar biliary obstruction (MHBO) via percutaneous unilateral or bilateral metal stenting. Relevant articles up to December 2019 were identified within the Web of science, Pubmed, Embase, and Cochrane Library databases. Stent dysfunction served as the primary endpoint, while we assessed technical success, clinical success, early and late complication incidence, and overall survival as secondary outcomes. Pooled odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were calculated for dichotomous variables. Hazard ratio (HR) with 95% CI were determined for overall survival. This meta-analysis included seven studies. Six studies were non-randomized controlled trials (RCTs) and one study was a RCT. A total of 888 MHBO patients underwent either percutaneous unilateral (n = 376) or bilateral (n = 512) metal stenting in these seven studies. We detected no significant differences in stent dysfunction rates (OR 0.97; 95% CI 0.67, 1.41, P = 0.89), technical success rates (OR 1.10; 95% CI 0.53, 2.29, P = 0.81), clinical success rates (OR 0.72; 95% CI 0.43, 1.22, P = 0.22), early complication rates (OR 0.82; 95% CI 0.34, 1.98, P = 0.66), late complication rates (OR 0.87; 95% CI 0.29, 2.63, P = 0.81), or overall survival (HR: 0.99; 95% CI 0.83, 1.17, P = 0.88) between unilateral and bilateral groups. Funnel plots demonstrated no obvious publication bias of these primary and secondary endpoints. From a clinical perspective, percutaneous unilateral and bilateral metal stenting are similarly effective for treatment of patients with MHBO. [ABSTRACT FROM AUTHOR]

Biotic and abiotic factors control aboveground biomass (AGB) and the structure of forest ecosystems. This study analyses the variation of AGB and stand structure of evergreen broadleaved forests among six ecoregions of Vietnam. A data set of 173 1-ha plots from 52 locations in undisturbed old-growth forests was developed. The results indicate that basal area and AGB are closely correlated with annual precipitation, but not with annual temperature, evaporation or hours of sunshine. Basal area and AGB are positively correlated with trees > 30 cm DBH. Most areas surveyed (52.6%) in these old-growth forests had AGB of 100–200 Mg ha−1; 5.2% had AGB of 400–500 Mg ha−1, and 0.6% had AGB of > 800 Mg ha−1. Seventy percent of the areas surveyed had stand densities of 300–600 ind. ha−1, and 64% had basal areas of 20–40 m2 ha−1. Precipitation is an important factor influencing the AGB of old-growth, evergreen broadleaved forests in Vietnam. Disturbances causing the loss of large-diameter trees (e.g., > 100 cm DBH) affects AGB but may not seriously affect stand density. [ABSTRACT FROM AUTHOR]

Purpose: To compare the clinical outcomes between unilateral and bilateral metal stenting for patients with malignant hilar biliary obstruction (MHO). Methods: This is a single-center, open-label, prospective, randomized study. Between January 2016 and March 2018, patients with MHO who were treated by percutaneous unilateral or bilateral metal stenting were enrolled. The primary endpoint was stent dysfunction. The secondary endpoints included technical success, clinical success, adverse events, and death. The protocol is registered at ClinicalTrials.gov (identifier: NCT02649712). Results: A total of 72 patients were randomly grouped for the unilateral (n = 36) or bilateral (n = 36) stenting. The bilateral stenting was performed through the side-by-side technique. While technically, the rates of success of unilateral and bilateral stenting were 83.3% (30/36) in both the cases (P = 1.000), the clinical rates of success in unilateral and bilateral stenting were 90.0% (27/30) and 96.7% (29/30), respectively (P = 0.605). Based on the per-protocol analysis, stent dysfunction was found in 5 and 3 patients in unilateral and bilateral groups, respectively (16.7% vs. 10.0%, P = 0.704). No predictor was observed to influence stent dysfunction. The median cumulative survival in the unilateral group was 122 days and in the bilateral group was 125 days (P = 0.844). We also observed higher levels of post-operative total bilirubin and pre-operative alanine aminotransferase, and the absence of post-operative anticancer treatment as predictors of worse survival. Conclusion: When compared, the bilateral and unilateral stentings provide a similar clinical effectiveness in patients with MHO. [ABSTRACT FROM AUTHOR]

Microstructure and mechanical properties of extruded Mg-7Sn-5Zn-xAl (x = 0, 1, 2 and 3 wt.%) alloy were investigated. The as-cast Mg-7Sn-5Zn alloy mainly comprised α-Mg dendrites, Mg2Sn and nanosized Mg-Zn phases in a Mg matrix, whereas the quasicrystal (icosahedral (I)) phase precipitated with the addition of Al. After extrusion, the grain size decreased due to dynamic recrystallization and the resulting particles were crushed and distributed along the extrusion direction. The highest tensile strength was exhibited by the extruded Mg-7Sn-5Zn-2Al alloy, which had a yield strength, ultimate tensile strength and elongation to failure of 198, 343 MPa and 18.7%, respectively. The high tensile strength was mainly attributed to grain refinement and precipitation strengthening of the Mg2Sn and icosahedral phases. [ABSTRACT FROM AUTHOR]

Surface flaw detection has been advanced steadily for decades thank to the advent of computer vision and artificial intelligence. However, there exist serious defect detection challenges in tube manufacturing, including the lack of a collected dataset, decision-making ambiguity in engineering judgment, and unstable lighting condition of the environment. This work aims to investigate an effective method to distinguish deformity that performs despite these challenges to deliver quality control in tube manufacturing. We present a new tube detection algorithm under limited data set and noisy environment due to unstable lighting condition, for which we introduced a feature vector to describe the defect problem. Using the feature vector and a neural network we are able to successfully detect and classify tube defect. [ABSTRACT FROM AUTHOR]

Purpose: To determine the clinical effectiveness and long-term outcomes of endovascular treatment for hepatic vein (HV)-type Budd-Chiari syndrome (BCS).Materials and methods: From June 2011 to August 2016, 68 consecutive patients with symptomatic HV-type BCS underwent endovascular treatment in our center. Data on the baseline characteristics, technical success, clinical success, and long-term outcomes were collected and analyzed retrospectively.Results: The technical success rate of endovascular treatment was 100%. Fifty patients underwent HV recanalization, and 18 underwent accessory HV (AHV) recanalization. The clinical success rate was 95.6% (65/68). During a mean follow-up period of 29.4 ± 13.6 months, 19 patients experienced re-obstruction of either the HV (n = 18) or the AHV (n = 1). The cumulative 1-, 2-, and 5-year primary patency rates were 80.0, 72.8, and 67.9%, respectively. The cumulative 1-, 2-, and 5-year secondary patency rates were 93.8, 90.3, and 82.9%, respectively. Univariate and multivariate analyses revealed that the independent predictor of a prolonged primary patency duration was recanalization of the AHV. Five patients died 1-28 months (median, 15 months) after treatment. The cumulative 1-, 2-, and 5-year survival rates were 96.9, 93.4, and 91.2%, respectively. There was no significant difference in survival between the HV and AHV recanalization groups.Conclusion: Endovascular treatment is effective for patients with HV-type BCS. It can result in excellent long-term patency and survival rates. If it is applicable, AHV recanalization should be considered prior to treatment in order to achieve a longer patency. [ABSTRACT FROM AUTHOR]

Purpose: To determine the clinical effectiveness and long-term outcome of stent insertion for malignant superior vena cava (SVC) syndrome. Materials and methods: From June 2010 to April 2016, 47 patients with malignant SVC syndrome were treated with stent insertion in our center. Data regarding the technical success, clinical success, and long-term outcome were collected and analyzed retrospectively. Results: SVC stent insertion was successfully performed in all patients. A total of 65 stents were used. No procedure-related complication occurred in these patients. The mean SVC pressure gradient decreased from 17.8 mmHg before stent insertion to 7.6 mmHg after stent insertion ( P < 0.001). Clinical success was 100%. During a mean follow-up period of 6 months (range 10 days-13 months), 25 patients underwent subsequent anti-cancer treatment. Six patients (12.8%) experienced re-obstruction of stent 1 to 189 days (median 76 days) after stent insertion. All patients died during the follow-up. The median stent patency time and survival were 339 and 167 days, respectively. The cumulative 3-, 6-, and 12-month stent patency rates were 93.4, 87.4, and 81.2%, respectively. The cumulative 3-, 6-, and 12-month survival rates were 83, 38.3, and 2.1%, respectively. The independent predictors of prolonging survival after stent insertion were lower tumor stage ( P = 0.018) and subsequent anti-cancer treatment after stent insertion ( P = 0.009). Conclusion: Stent insertion is a simple, safe, and effective method for patients with malignant SVC syndrome. Subsequent anti-cancer treatment after stent insertion may increase the survival. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the feasibility and effectiveness of integrated self-expanding Y-shaped airway stent placement for patients with carinal stenosis. Materials and methods: From May 2010 to March 2015, 12 consecutive patients with carinal stenosis, treated by placement of integrated self-expanding Y-shaped airway stent, were included this retrospective study. Data on technical success, clinical success, and follow-up were analyzed. Results: Technical success was 100 %. Eleven uncovered stents and one covered stent placed in 12 patients. Eleven patients underwent stent insertion under local pharyngeal anesthesia, and one patient underwent stent insertion under general anesthesia. Clinical success was 100 %. The respiratory difficulty improved instantly after treatment. The average Hugh-Jones classification grade and arterial oxygen saturation improved from 4.3 ± 0.6 and 83.0 ± 2.6 % before treatment to 1.4 ± 0.5 ( p < 0.001) and 95.4 ± 1.2 % ( p < 0.001) after treatment, respectively. During 3-15 months (mean 6.5 ± 3.3 months) of follow-up, two patients experienced the re-stenosis of the stent 75 and 78 days after treatment. All patients died during the follow-up. Survival after stent insertion ranged from 96 to 432 days (median 165 days). The cumulative 6- and 12-month survival rates were 41.7 and 8.3 %, respectively. Conclusions: Placement of integrated self-expanding Y-shaped airway stent is a simple, safe, and effective method for patients with carinal stenosis. [ABSTRACT FROM AUTHOR]