Search

Background: Worldwide, gastric cancer is a leading cause of cancer incidence and mortality. This study aims to devise and validate a scoring system based on readily available clinical data to predict the risk of gastric cancer in a large Chinese population. Methods: We included a total of 6,209,697 subjects aged between 18 and 70 years who have received upper digestive endoscopy in Hong Kong from 1997 to 2018. A binary logistic regression model was constructed to examine the predictors of gastric cancer in a derivation cohort (n = 4,347,224), followed by model evaluation in a validation cohort (n = 1,862,473). The algorithm's discriminatory ability was evaluated as the area under the curve (AUC) of the mathematically constructed receiver operating characteristic (ROC) curve. Results: Age, male gender, history of Helicobacter pylori infection, use of proton pump inhibitors, non‐use of aspirin, non‐steroidal anti‐inflammatory drugs (NSAIDs), and statins were significantly associated with gastric cancer. A scoring of ≤8 was designated as "average risk (AR)". Scores at 9 or above were assigned as "high risk (HR)". The prevalence of gastric cancer was 1.81% and 0.096%, respectively, for the HR and LR groups. The AUC for the risk score in the validation cohort was 0.834, implying an excellent fit of the model. Conclusions: This study has validated a simple, accurate, and easy‐to‐use scoring algorithm which has a high discriminatory capability to predict gastric cancer. The score could be adopted to risk stratify subjects suspected as having gastric cancer, thus allowing prioritized upper digestive tract investigation. [ABSTRACT FROM AUTHOR]

This paper solves the problem of block sparse vector recovery using the block ℓ1−αℓq$\ell _1-\alpha \ell _q$‐minimization model. Based on the block restricted isometry property (B‐RIP) condition, exact block sparse vector recovery result is obtained. The theoretical bound for the block ℓ1−αℓq$\ell _1-\alpha \ell _q$‐minimization model are also obtained when measurements are depraved by the noises. [ABSTRACT FROM AUTHOR]

This paper focuses on the compressed sensing ℓ1−ℓ2$\ell _1-\ell _2$‐minimization model and develops new bounds on cumulative coherence μ1(s)$\mu _1(s)$. It is pointed out that if cumulative coherence μ1(s)$\mu _1(s)$ satisfies Equation (2) or (11), then the sparse signal can stably recover in noise model and exactly recover in free noise by ℓ1−ℓ2$\ell _1-\ell _2$‐minimization model. From this paper, it is found that based on some condition of cumulative coherence, the ℓ1−ℓ2$\ell _1-\ell _2$‐minimization model can exactly recover s‐sparse signals in noiseless cases and stably recover s‐sparse signals in the noise cases. [ABSTRACT FROM AUTHOR]

In the field of compressed sensing, ℓ1−2$\ell _{1-2}$‐minimization model can recover the sparse signal well. In dealing with the ℓ1−2$\ell _{1-2}$‐minimization problem, most of the existing literature uses the difference of convex algorithm (DCA) to solve the unrestricted ℓ1−2$\ell _{1-2}$‐minimization model, that is, model (4). Although experiments have proved that the unrestricted ℓ1−2$\ell _{1-2}$‐minimization model can recover the original sparse signal, the theoretical proof has not been established yet. This paper mainly proves theoretically that the unrestricted ℓ1−2$\ell _{1-2}$‐minimization model can recover the sparse signal well, and makes an experimental study on the parameter λ in the unrestricted minimization model. The experimental results show that increasing the size of parameter λ in (4) appropriately can improve the recovery success rate. However, when λ is sufficiently large, increasing λ will not increase the recovery success rate. [ABSTRACT FROM AUTHOR]

To reveal the effect of ceria particle size on dispersion and structure of supported Pt catalysts during preparation, activation, and reaction testing, a unique CeO2/Al2O3 support (CA−c) with smaller CeO2 particle size and more surface defects was prepared using a colloidal CeO2 precursor, comparing with a conventional CeO2/Al2O3 support (CA−n) using cerium nitrate as precursor. More atomically dispersed Pt and abundant Pt−O−Ce structures were observed in the Pt/CA−c catalyst than in the Pt/CA−n catalyst. Both parent catalysts received significant enhancement on their catalytic CO oxidation activities if activated by 10% hydrogen at 400 °C before reaction. Between the two representative catalysts, the extent of activity enhancement upon activation was more pronounced for Pt/CA−c. We found that smaller Pt clusters with more active ionic Pt sites were generated on the activated Pt/CA−c catalyst, while agglomerated larger Pt particles with more metallic sites were formed on the activated Pt/CA−n. The facile formation of Ce3+ was also indicative of more active metal‐support interfaces in the activated Pt/CA−c catalyst. These results highlight the importance of regulating ceria support particles to enable a controlled anchoring and subsequent activation of Pt single atoms for low‐temperature CO oxidation reaction. [ABSTRACT FROM AUTHOR]

Summary: Background: Gastric bypass is considered an effective treatment of co‐existing gastro‐oesophageal reflux (GERD) and obesity. Previous studies have had small sample sizes, short follow‐up or substantial loss to follow‐up. Aim: To assess the long‐term risk of remaining/recurring reflux symptoms after gastric bypass. Methods: This was a nationwide cohort study of all adults with preoperative reflux who underwent gastric bypass in Sweden between 2006 and 2015, with complete follow‐up through 2016. The outcome was remaining/recurring reflux symptoms, defined as use of proton pump inhibitors or histamine‐2 receptor antagonists for >6 months after surgery. Cumulative incidence and risk factors of reflux were assessed with multivariable Poisson regression. Results: Among 2454 participants (81.7% female; mean age: 46.1 years, SD: 9.8 years), who were followed for median 4.6 years (interquartile range: 3.1‐6.3 years), reflux recurred in 48.8% (95% confidence interval [95% CI], 46.8‐51.0) of participants within 2 years of gastric bypass and remained stable up to 10 years after surgery (yearly change in incidence rate ratio [IRR] of 1.00; 95% CI, 0.99‐1.02). Risk factors for recurring reflux were high preoperative dose of anti‐reflux medication (IRR 1.77; 95% CI, 1.60‐1.96 compared with low dose), older age (IRR 1.12; 95% CI 1.02‐1.24 comparing age >50 with <40 years), female sex (IRR 1.28; 95% CI, 1.16‐1.42) and comorbidity (IRR 1.26; 95% CI, 1.14‐1.39 comparing Charlson Comorbidity Index ≥2 with 0). Conclusions: Reflux symptoms decrease rapidly after gastric bypass, but around half of operated patients require continuous anti‐reflux medication. The treatment efficacy of gastric bypass on reflux symptoms might have been overestimated. [ABSTRACT FROM AUTHOR]

Catalytic combustion of methane is widely used in industrial and transportation activities. The commonly used Pd‐based catalysts, however, are easily deactivated under hydrothermal conditions. In this work, we adopted a novel strategy to prepare a GaOx‐doped Pd/Al2O3 catalyst via the oxidative transformation of intermetallic Pd5Ga3 nanocrystals supported on γ‐Al2O3. We observed a synergistic effect between palladium and gallium oxide via formation of a bi‐functional active Pd−O−Ga phase, resulting in a highly active and exceptionally stable catalyst that could markedly suppress the sintering of noble metals under harsh conditions (hydrothermal treatment at 750 °C). Moreover, the presence of a large amount of surface oxygen vacancies and the surface Pd−O−Ga phase could promote methane combustion over the catalysts. It is believed that such a novel dual‐metal catalyst is promising in practical applications for methane combustion. Effective synergy: The Pd−GaOx/Al2O3 catalysts are prepared via the oxidative transformation of intermetallic Pd5Ga3 nanocrystals supported on Al2O3. A synergistic effect between palladium and gallium oxide via formation of a bi‐functional active Pd−O−Ga phase is observed, resulting in a highly active and exceptionally stable catalyst that can markedly suppress the sintering of noble metals under harsh conditions. Surface oxygen vacancies and the surface Pd−O−Ga phase are the catalytically active sites. [ABSTRACT FROM AUTHOR]

Porous cube-aggregated monodisperse Co3O4 microspheres and their supported gold ( xAu/Co3O4 microsphere, x=1.6-7.4 wt %) nanoparticles (NPs) were fabricated using the glycerol-assisted solvothermal and polyvinyl alcohol-protected reduction methods. Physicochemical properties of the materials were characterized by means of numerous analytical techniques, and their catalytic activities were evaluated for the oxidation of toluene and CO. It is shown that the cubic Co3O4 microspheres were composed of aggregated cubes with a porous structure. The gold NPs with a size of 3.2-3.9 nm were uniformly deposited on the surface of Co3O4 microspheres. Among the Co3O4 microsphere and xAu/Co3O4 microsphere samples, the 7.4Au/Co3O4 microspheres performed the best, giving T90 % values (the temperature required for achieving a CO or toluene conversion of 90 % at a weight hourly space velocity of 20 000 mL g−1 h−1) of −8 and 250 °C for CO and toluene oxidation, respectively. In the case of 3.0 vol % water vapor introduction, a positive effect on CO oxidation and a small negative effect on toluene oxidation were observed over the 7.4Au/Co3O4 microsphere sample. The apparent activation energies obtained over the xAu/Co3O4 microsphere samples were in the ranges of 40.7-53.6 kJ mol−1 for toluene oxidation and 21.6-34.6 kJ mol−1 for CO oxidation. It is concluded that the higher oxygen adspecies concentration, better low-temperature reducibility, and stronger interaction between gold NPs and Co3O4 as well as the porous microspherical structure were responsible for the excellent catalytic performance of 7.4Au/Co3O4 microsphere. [ABSTRACT FROM AUTHOR]