Roles of Oxygen Vacancies and Excess Electron Localization on Ceria Surfaces: First Principles Study

In this study, we investigate the (111), (110) and (100) surfaces of reduced ceria (CeO2) using density functional theory (DFT) within DFT+U. We examine the process by which oxygen vacancy sites form on CeO2 (111), (110), and (100) surfaces as well as the stability of these sites close to the ceria surface regions. Our calculations demonstrate that electron localizations of the reduced CeO2 on each of these three surface terminations are caused by oxygen vacancies, both surface and subsurface, which results in the emergence of Ce3+ sites. The oxygen vacancy at the surface and subsurface of CeO2 (111) surfaces results in the formation of Ce3+ at the vacancys next-closest neighbor. Ce3+ is formed at the sites closest to the oxygen vacancy sites on CeO2 (100) and CeO2 (110) surfaces. The calculated total density of states (TDOS) of the reduced surfaces displays that the Ce 4 f states are partially occupied and appeared in a new state near the band gap compared to that for the unreduced ceria surfaces. The existence of these new states was found to have a large effect on the nature of ceria. In (111) ceria surface, the material remains semiconductor with a smaller band gap. However, (110) and (100) ceria surfaces become semi-metallic due to the crossing of a new state of the fermi level that converts ceria to become semi- metallic material. Therefore, the conductivity and chemical properties of ceria are expected to be modified by the creation of oxygen vacancy. The reduced ceria expects to catalyze the dissociation of molecules on its surface. The dissociation is assisted by the oxidation of Ce3+ that is generated on reduced ceria surfaces

Hernie obturatrice étranglée: à propos de deux cas

La hernie obturatrice (HO) est rare. Elle est à l'origine de 0,2 à 1,6% des occlusions mécaniques de l'intestin grêle avec un taux de mortalité etmorbidité après chirurgie est respectivement de 35 et 18%. Nous rapportons le cas de deux patientes chez qui le diagnostic de HO étranglée est établie dans le cadre du bilan d'une occlusion. La HO est une entité dont le diagnostic préopératoire est difficile en raison de la faible spécificité clinique. L'examen tomodensitométrique semble être une aide majeure au diagnostic  étiologique. Mais une fois le diagnostic d'occlusion posé, une intervention en urgence permettra d'en préciser l'étiologie et d'en réaliser le traitement. Tout retard thérapeutique majore la mortalité et la morbidité

Cytotoxic evaluation and concurrent analysis of two diterpenes in the chloroform extract of Plectranthus barbatus using a validated HPTLC-UV method

The objective of this study was to develop a validated high-performance thin layer chromatography (HPTLC) method for the concurrent analysis of two diterpenes Sugiol (compound 1) and 11,14-dihydroxy-8,11,13-abietatrien-7-one (compound 2) in Plectranthus barbatus chloroform extract (PBCE) and to investigate cytotoxicity of both compounds. The chromatographic estimations were carried out using toluene : ethyl acetate : formic acid (8.2:1.3:0.5 v/v/v) as mobile phase. The compact spots of biomarkers were scanned at λmax= 275 nm. Cytotoxic evaluation of both compounds was performed using follicular thyroid cancer cells (FRO cells). A well resolved, compact and intense peaks of compound 1 (Rf = 0.550 ± 0.001) and compound 2 (Rf = 0.700 ± 0.002) were recorded. The proposed method for both compounds was recorded as simple, linear, precise (% RSD = 1.02-1.25), accurate (98-100%), robust and sensitive for the analysis of both compounds. Cytotoxicity evaluation showed significant cell cytotoxicity at 100 μg/mL concentration against the FRO cancer cells after 72 h of incubation. Both compounds were recorded as cytotoxic, however compound 1 showed significant cytotoxic effects. The proposed HPTLC method was found to be suitable for routine analysis of these two biomarkers in chloroform extract of P. barbatus. Both compounds were found to be cytotoxic against FRO cancer cells. KEY WORDS: Diterpenes, Sugiol, Plectranthus barbatus, Cytotoxicity, HPTLC Bull. Chem. Soc. Ethiop. 2018, 32(3), 407-419.DOI: https://dx.doi.org/10.4314/bcse.v32i3.

Synthesis, XRD and HS-Analysis

An efficient microwave-assisted one-step synthetic route toward Mannich bases is developed from 4-hydroxyacetophenone and different secondary amines in quantitative yields, via a regioselective substitution reaction. The reaction takes a short time and is non-catalyzed and reproducible on a gram scale. The environmentally benign methodology provides a novel alternative, to the conventional methodologies, for the synthesis of mono- and disubstituted Mannich bases of 4-hydroxyacetophenone. All compounds were well-characterized by FT-IR, 1H NMR, 13C NMR, and mass spectrometry. The structures of 1-{4-hydroxy-3-[(morpholin-4-yl)methyl]phenyl}ethan-1-one (2a) and 1-{4-hydroxy-3-[(pyrrolidin-1-yl)methyl]phenyl}ethan-1-one (3a) were determined by single crystal X-ray crystallography. Compound 2a and 3a crystallize in monoclinic, P21/n, and orthorhombic, Pbca, respectively. The most characteristic features of the molecular structure of 2a is that the morpholine fragment adopts a chair conformation with strong intramolecular hydrogen bonding. Compound 3a exhibits intermolecular hydrogen bonding, too. Furthermore, the computed Hirshfeld surface analysis confirms H-bonds and π–π stack interactions obtained by XRD packing analyses

Prevalence of Asymptomatic Hyperuricemia and its Association with Prediabetes, Dyslipidemia and Subclinical Inflammation Markers among Young Healthy Adults in Qatar

Aim: To investigate the prevalence of asymptomatic hyperuricemia in Qatar and to examine its association with changes in markers of dyslipidemia, prediabetes and subclinical inflammation. Methods: A cross-sectional study of young adult participants aged 18 - 40 years old devoid of comorbidities. Exposure was defined as uric acid level, and outcomes were defined as levels of different blood markers. De-identified data were collected from Qatar BioBank. T-tests, correlation tests and multiple linear regression were all used to investigate the effects of hyperuricemia on blood markers. Statistical analyses were conducted using STATA 16. Results: The prevalence of asymptomatic hyperuricemia is 21.2% among young adults in Qatar. Differences between hyperuricemic and normouricemic groups were observed using multiple linear regression analysis and found to be statistically and clinically significant after adjusting for age, gender, BMI, smoking and exercise. Significant associations were found between uric acid level and HDL-c p = 0.019 (correlation coefficient -0.07 (95% CI [-0.14, -0.01]); c-peptide p = 0.018 (correlation coefficient 0.38 (95% CI [0.06, 0.69]) and monocyte to HDL ration (MHR) p = 0.026 (correlation coefficient 0.47 (95% CI [0.06, 0.89]). Conclusion: Asymptomatic hyperuricemia is prevalent among young adults and associated with markers of prediabetes, dyslipidemia, and subclinical inflammation

The adoption of ChatGPT marks the beginning of a new era in educational platforms

Technology has significantly transformed knowledge, education, and access to information by introducing online learning platforms, interactive games, and virtual reality simulations in traditional classrooms, creating a dynamic, engaging, and inclusive learning environment. The ChatGBT project (a pre-developed transformer for training) is a remarkable achievement in artificial intelligence technology. It allows students tailored and efficient learning experiences by providing individual feedback and explanations. ChatGPT e-learning platform has been extensively studied for its adoption and acceptance, but there is a significant gap in research on its acceptability and use, highlighting the need for further exploration. The goal of this work is to bridge this disparity by introducing a comprehensive model that includes three basic elements: performance expectation, expected effort, and social impact. A total of 241 graduate students were surveyed and their data were analyzed using structural equation modeling techniques. The results indicate that “expectation of performance and expected effort” have the greatest impact and importance in determining students’ intentions to use learning platforms via ChatGPT, while social influence does not play an important role. This study enhances the current body of knowledge related to artificial intelligence and environmental sustainability, and provides important insights for professionals, policymakers, and producers of artificial intelligence products. These observations may provide guidance for creating and implementing artificial intelligence technologies to match consumers’ needs and preferences more effectively, while also taking into account broader environmental conditions

Predicting risk factors for thromboembolic complications in patients with sickle cell anaemia - lessons learned for prophylaxis

Objective: To assess the clinical and laboratory predictors of venous thromboembolism (VTE) in patients with sickle cell anaemia (SCA) and its relationship to morbidity and mortality. Methods: This retrospective case-control study analysed data from patients with SCA that experienced VTE compared with matched control patients with SCA but no VTE (2:1 ratio). Results: A total of 102 patients with SCA were enrolled (68 cases with VTE and 34 controls). Amongst the 68 cases (median age, 29.5 years), 26 (38.2%) presented with isolated pulmonary embolism (PE). A higher prevalence of splenectomy (73.5% versus 35.3%) was observed in the cases compared with the controls. A significantly higher prevalence of central venous catheter (CVC) insertion (42.6% versus 8.8%) was observed in the cases compared with the controls. High white blood cell counts, serum lactic dehydrogenase (LDH), bilirubin and C-reactive protein (CRP) and low haemoglobin (Hb) and HbF were significant risk factors for VTE. Forty-two cases (61.8%) developed acute chest syndrome, 10 (14.7%) had a stroke and seven (10.3%) died. Conclusions: VTE in patients with SCA has a high impact on morbidity and mortality. PE was the leading presentation of VTE, with CVC insertion, high LDH, bilirubin, CRP and white blood cell counts along with low Hb and HbF constituting other significant risk factors

Evidence of a structure in (K)over-bar(0)Lambda(+)(c) consistent with a charged Xi(c)(2930)(+), and updated measurement of (B)over-bar(0) -> (K)over-bar(0)Lambda(+)(c) (Lambda)over-bar(c)(-) at Belle

We report evidence for the charged charmed-strange baryon Xi(c)(2930)(+) with a signal significance of 3.9 sigma with systematic errors included. The charged Xi(c)(2930)(+) is found in its decay to K-S(0)Lambda(+)(c) in the substructure of (B) over bar (0) -> K-S(0)Lambda(+)(c)(Lambda) over bar (-)(c) decays. The measured mass and width are [2942.3 +/- 4.4(stat.) +/- 1.5(syst.)] MeV/c(2) and [14.8 +/- 8.8(stat.) +/- 2.5(syst.)] MeV, respectively, and the product branching fraction is B((B) over bar (0) -> Xi(c)(2930)(+)(Lambda) over bar (-)(c)) B(Xi(c)(2930)(+) -> (K) over bar (0)(S)Lambda(+)(c)) = [2.37 +/- 0.51(stat.) +/- 0.31 (syst.)] x 10(-4). We also measure B((B) over bar (0) -> (K) over bar (0)(S)Lambda(+)(c)(Lambda) over bar (-)(c)) = [3.99 +/- 0.76(stat.) +/- 0.51(syst.)] x 10(-4) with greater precision than previous experiments, and present the results of a search for the charmonium-like state Y (4660) and its spin partner, Y-eta, in the Lambda(+)(c)(Lambda) over bar (-)(c) invariant mass spectrum. No clear signals of the Y (4660) or Y-eta are observed and the 90% credibility level (C.L.) upper limits on their production rates are determined. Thesemeasurements are obtained from a sample of (772 +/- 11) x 10(6) B (B) over bar pairs collected at the Upsilon(4S) resonance by the Belle detector at the KEKB asymmetric energy electron-positron collider

2-Benzyloxynaphthalene aminoalkylated chalcone designed as acetylcholinesterase inhibitor: Structural characterisation, in vitro biological activity and molecular docking studies

The design of an acetylcholinesterase inhibitor with multifunctional properties became the perspective for the development of an effective drug against Alzheimer's disease. Towards this target, 1-{4-hydroxy-3-[(piperidin-1-yl)methyl]phenyl}ethan-1-one (chalcone 3) was prepared and studied as an acetylcholinesterase inhibitor. The novel chalcone 3 was synthesised via Claisen-Schmidt condensation reaction with 84% yield and characterized using 1D and 2D NMR spectroscopy. The in vitro bioactivity studies of chalcone 3 demonstrated excellent inhibitory activity against AChE (IC50 1.0 nM) showing 33-fold better inhibition than donepezil, biometal chelating ability and moderate antioxidant activity. Chalcone 3 with these fascinating multifunctional proprieties can be a good candidate for the development of AD treatments. A molecular modelling investigation revealed that chalcone 3 showed dual binding inhibition of AChE enzyme. XRD shows short intra- and inter-molecular interactions with two chalcone 3 molecules per cell. Interesting Hirshfeld Surface Analysis (HSA) was conducted showing explicit agreement with the XRD analysis

Search for the decay B+→K‾∗0K∗+B^+\rightarrow\overline{K}{}^{*0}K^{*+} at Belle

We report a search for the rare charmless decay $B^+\rightarrow\overline{K}{}^{*0}K^{*+}$ using a data sample of $772\times10^6$ $B\bar{B}$ pairs collected at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. No statistically significant signal is found and a 90% confidence-level upper limit is set on the decay branching fraction as $\mathcal{B}(B^+\rightarrow\overline{K}{}^{*0}K^{*+}) <1.31\times 10^{-6}$.Comment: 8 pages, 3 figures, submitted to PRD(RC