Search

The traditional monopile foundation is confronted with challenges in the context of the new generation of offshore wind turbines with greater power capacities. On this basis, the single pile-friction footing hybrid foundation is investigated, whose bearing capacity is largely improved by combining a circular friction footing at the mudline. This paper discusses the failure mechanisms and bearing capacities of this hybrid foundation in sand under combined vertical-horizontal-moment (V – H - M) loadings by laboratory experiments and the finite element method. By adopting Particle Image Velocimetry (PIV) technology in model tests, failure mechanisms of a single pile and the hybrid system are compared. The results show that the cavitation and compaction phenomenon can be captured in the depth range of 0–0.7 pile embedment depth) for the hybrid foundation. Also, due to the settlement of the footing, a deformation area with a concave area and a small peak value can be found under the footing, which is quite different from that of the pile under V – H - M combined loadings. Intensive parametric studies were performed through FE method, and the results indicate that increasing the footing diameter has a more pronounced effect on the bearing capacity compared to that of increasing the length-diameter ratio of the pile. • The failure mechanism of the monopile and single pile-friction footing hybrid foundation in sand is explored through Particle Image Velocimetry technology. • Bearing capacities of the hybrid foundation are investigated, considering influences of foundation geometry and loading conditions. • The cavitation and compaction of soil mainly occurs within the depth of 0-0.7 pile embedment depth. • Increasing the footing diameter can improve the foundation capacity more effectively than increasing the pile length. [ABSTRACT FROM AUTHOR]

Mixed μ -azido-Schiff-base palladacycles [Pd{ C , N - κ 2 -(4-R)C 6 H 3 CH = N-C 6 H 3 -2,6- i -Pr 2 }( μ 2 -N 3 )] 2 (R = H, 1 ; OMe, 2 ) served as a metal-template for the synthesis of unusual dicarbodiimido bridged complexes [( μ 2 -NCN-Xyl)Pd{ C , N - κ 2 -(4-R)C 6 H 3 CH = NC 6 H 3 -2,6- i -Pr 2 }] 2 (R = H; OMe) and mixed tetrazolato-isocyanido complexes [Pd( C , N - κ 2 -(4-R)C 6 H 3 CH = NC 6 H 3 -2,6- i -Pr 2 )(CN 4 -Xyl)(CN-Xyl)] (R = H; OMe). Reactions of ethyl isothiocyanate with 1 and 2 gave the ditetrazole-thiolato bridged Pd complexes [( μ 2 -SCN 4 -C 2 H 5 )Pd( C , N - κ 2 -(4-R)C 6 H 3 CH = NC 6 H 3 -2,6- i -Pr 2 )] 2 . All these complexes were fully characterized by FT-IR, NMR spectroscopy, elemental analysis and/or X-ray crystallography. [ABSTRACT FROM AUTHOR]

The various industries, sectors, and citizens' daily lives have undergone significant changes after the outbreak of the COVID-19 pandemic. The researchers collected and analyzed PM2.5 samples including secondary inorganic ions (SO42−, NO3−, and NH4+, namely SNA), organic carbon (OC), elemental carbon (EC), and other 16 metal elements in Beijing in 2019 (before the pandemic) and 2020 (after the pandemic). The particulate matter (PM2.5) concentration in the autumn and winter of 2020 is 21.16 µg/m3 and 14.05 µg/m3 lower than in 2019, respectively. The contribution of six sources of pollution, including coal combustion, secondary sources, transportation-related sources, dust, Industrial I, and Industrial II, were analyzed using the Positive Matrix Factorization (PMF) model. Due to the impacts of the COVID-19 pandemic, more and more people are choosing private transportation, such as private cars, instead of public transportation. As a result, the contribution of PM2.5 pollution related to transportation increased after the pandemic. The metal elements measured during the sampling period represent only a very small fraction (1%) of PM2.5. However, their health risk to humans cannot be ignored because of the toxicity of some metallic elements, and the carcinogenic risks induced by metal elements in PM2.5 exceeded the safety threshold (>10−6) during the autumn and winter of 2019 and 2020. Arsenic (As) contributes the most to carcinogenic risk, so controlling arsenic emissions is the primary approach to reducing cancer risk in Beijing. Considering the contribution to the health risk from various sources obtained in PMF, coal combustion is the most significant contributor to cancer risk. Therefore, serious consideration should be given to controlling coal combustion at the local and regional levels to reduce health risks in Beijing. [ABSTRACT FROM AUTHOR]

Abstract: Bis-bidentate tetra-coordinated oxalato bridged binuclear Schiff-base palladacycles [Pd{C,N-κ 2-(4-R)C6H3CH NC6H3-2,6-i-Pr2]2(μ-η 2-η 2-C2O4) (R = H; OMe) were synthesized. Reactions of μ-oxalato bridged Schiff-base palladacycles [Pd{C,N-κ 2-(4-R)C6H3CH NC6H3-2,6-i-Pr2]2(μ-η 2-η 2-C2O4) (R = H; OMe) with 1,4-bis(diphenylphosphino)butane (dppb) and 1,4-bis(diphenylphosphino)pentane (dppp) generated discrete pseudo-macrocycles with 1,1′-bicoordinated oxalato bridge. Unexpectedly, μ-oxalato bridged Schiff-base palladacycle [Pd(C,N-κ 2-C6H4CH NC6H3-2,6-i-Pr2)]2(μ-η 2-η 2-C2O4) reacted with PPh3 to form unusual bidentate/monodentate tri-coordinated oxalato bridged binuclear cyclopalladated complex [Pd(C,N-κ 2-C6H4CH NC6H3-2,6-i-Pr2)(PPh3)](μ-η 2-η 1-C2O4)[Pd(C-κ 1-C6H4CH NC6H3-2,6-i-Pr2)(PPh3)]. [Copyright &y& Elsevier]

Background: Novel biomarkers are required in gastric cancer (GC) treated by immunotherapy. Epstein-Barr virus (EBV) infection induces an immune-active tumor microenvironment, while its association with immunotherapy response is still controversial. Genes underlying EBV infection may determine the response heterogeneity of EBV + GC. Thus, we screened hub genes associated with EBV infection to predict the response to immunotherapy in GC. Methods: Prognostic hub genes associated with EBV infection were screened using multi-omic data of GC. EBV + GC cells were established and confirmed by EBV-encoded small RNA in situ hybridization (EBER-ISH). Immunohistochemistry (IHC) staining of the hub genes was conducted in GC samples with EBER-ISH assay. Infiltrating immune cells were stained using immunofluorescence. Results: CHAF1A was identified as a hub gene in EBV + GC, and its expression was an independent predictor of overall survival (OS). EBV infection up-regulated CHAF1A expression which also predicted EBV infection well. CHAF1A expression also predicted microsatellite instability (MSI) and a high tumor mutation burden (TMB). The combined score (CS) of CHAF1A expression with MSI or TMB further improved prognostic stratification. CHAF1A IHC score positively correlated with the infiltration of NK cells and macrophages M1. CHAF1A expression alone could predict the immunotherapy response, but its CS with EBV infection, MSI, TMB, or PD-L1 expression showed better effects and improved response stratification based on current biomarkers. Conclusions: CHAF1A could be a novel biomarker for immunotherapy of GC, with the potential to improve the efficacy of existing biomarkers. [ABSTRACT FROM AUTHOR]

Cyclometallated Pd(II) complexes containing arylimine and salicylaldimine co-ligands were synthesized by the reactions of cyclopalladated chloro dimers [Pd{(4-R)C 6 H 3 CH N–C 6 H 3 -2,6- i -Pr 2 }( μ -Cl)] 2 (R = H; OMe) with salen-based ligands derived from rimantadine. The complexes were characterized by FTIR, NMR spectroscopy, elemental analysis and X-ray crystallography. Interaction of cyclometallated Pd(II) complexes with BSA was studied by fluorescence and synchronous fluorescence spectroscopy. The fluorescence intensities of protein are decreased gradually with increasing concentration of complexes. In the synchronous fluorescence spectra of BSA at Δ λ = 15 nm and Δ λ = 60 nm, the fluorescence of intensities of protein also are decreased with increasing concentration of complexes. [ABSTRACT FROM AUTHOR]

Abstract: The interaction between p-nitrophenol (PNP) with bovine serum albumin (BSA) was investigated by fluorescence quenching, UV–visible absorption, circular dichroism (CD) and Fourier transform infrared (FT-IR) spectroscopy under the simulative physiological conditions. It is found that PNP has a strong ability to quench the intrinsic fluorescence of BSA by forming a 1:1 ground-state complex with a binding constant of about 104 Lmol−1. The values of the calculated thermodynamic parameters suggest that hydrogen bonds and hydrophobic forces played major roles in stabilizing the complex. The displacement experiments indicate that the binding of PNP to BSA primarily occurred in the sub-domain IIA (site I) of BSA. The binding distance r was calculated to be 1.58nm based on the theory of Förster׳s non-radiation energy transfer. The analysis of synchronous fluorescence, FT-IR, CD, and three-dimensional fluorescence spectra reveals that the microenvironment of amino acid residues and the conformation of BSA were changed after addition of PNP. [Copyright &y& Elsevier]

A photochromic film based on an inorganic‐organic hybrid, Na3H(H2O)2[β‐Mo8O26](C12H8N4O2)2·19H2O (1), is developed for the first time. Compound 1 was in situ synthesized and structurally characterized by single‐crystal X‐ray crystallography, and a dimerization reaction of isoniazid can be directly observed during the synthesis process. Together with the polymolybdate, the azo bond in the dimerization product N,N'‐bis(isonicotinamide) hydrazide showed photochromic properties under illumination, widening the light absorption range of polymolybdate. Irradiation experiments of the prepared film indicated an excellent waterproof and recyclable layered material, which demonstrated a distinctive way of extending the application of polyoxometalate based hybrid inorganic‐organic functional materials in the field of photocatalysis. [ABSTRACT FROM AUTHOR]

Abstract An electrochemical method to determine pyrophosphate (PPi) was developed using a glassy carbon electrode. PPi displays a new cathodic peak under a positive potential during benzoquinone (BQ) reduction. This new peak is caused by a sharp change in pH near the electrode surface. At pH 4.500, one mole of PPi is hydrolyzed to form two moles of H 2 PO 4 −, leading to a new intense cathodic peak. The peak current difference of the two new peaks, which is caused by PPi hydrolysis, depends on the PPi concentration but not the BQ concentration. The peak current difference is linearly related to PPi concentrations in the range of 1.0 × 10−5–7.0 × 10−4 mol L−1 (R2 = 0.998). Moreover, H 2 PO 4 −, NaF, NaCl, sugar, and acesulfame do not affect the peak current difference. The proposed method was applied to measure the PPi content of toothpaste samples. [ABSTRACT FROM AUTHOR]

A facile and sensitive fluorescence protocol for nucleobase detection was developed based on carbon nanodot (CD) chemosensors. The novel fluorescent CDs were prepared using four kinds of nucleobases (including adenine, guanine, thymine and cytosine) as separate carbon sources via simple hydrothermal strategy. The quantum yield of adenine CDs (A-CDs), guanine CDs (G-CDs), thymine CDs (T-CDs) and cytosine CDs (C-CDs) was checked as 15.1%, 28.3%, 10.6% and 11.7%, respectively. Four CDs can recognize their complementary nucleobases based on the principle of complementary base pairing. Their fluorescence was linearly quenched with the increase of nucleobase concentrations under optimal conditions. Combining the calibration curve, quantitative assay of nucleobase in solution can be realized. For example, A-CDs could determine thymine in the concentration range of 2–20 mM with a detection limit of ca. 0.053 mM, and the linear equation is fitting as (I 0 −I) / I = 0.01961 × C T (mM) + 0.01756 (R 2 = 0.994). Thymine can induce the fluorescence lifetime of A-CDs decreasing from 5.58 to 3.34 ns, indicating a dynamic quenching mechanism. The novel nucleobase sensors were also evaluated in specific solution environment. A-CDs showed a relatively minor relative standard deviation (< 4.0%) in fetal calf serum solution, indicating a high accuracy and credibility of the sensing system. In view of the excellent sensitivity, preferable biocompatibility as well as simple constructing method, the sensing platform derived from the nucleobase-based CDs present great potential in biological sensing applications. [ABSTRACT FROM AUTHOR]

A facile and efficient synthesis of 4-quinolones was described via intramolecular Houben-Hoesch reaction of β-arylamino acrylonitriles mediated by triflic anhydride in N , N -dimethylformamide. [ABSTRACT FROM AUTHOR]

Dipicolinate sensitized LaF 3 :Tb 3+ luminescent nanoparticles (DPA-NPs) have been successfully synthesized and characterized for their morphology, structural and optical properties. It was found that the prepared DPA-NPs were spherical with an average diameter of 10 nm and their surfaces were capped by citric acid radicals and DPA. And then the interaction between DPA-NPs and bovine serum albumin (BSA) was investigated by fluorescence quenching, UV–visible absorption, circular dichroism (CD) and Fourier transform infrared (FT-IR) spectroscopy under the simulative physiological conditions. The results showed that DPA-NPs had a strong ability to quench the intrinsic fluorescence of BSA by forming 1:1 ground-state complexes with a binding constant of about 10 4 L mol −1 . Moreover, the values of the calculated thermodynamic parameters suggested that hydrophobic forces and hydrogen bonds played major roles in stabilizing the complex. The displacement experiments indicated that the binding of DPA-NPs primarily occurred in sub-domain II A (site I) of BSA. The binding distance r was calculated to be 1.9 nm based on the theory of Förster׳s non-radiation energy transfer. Finally, the analysis of synchronous fluorescence, FT-IR, CD, and three-dimensional fluorescence spectra revealed that the microenvironment of amino acid residues and the conformation of BSA were changed after the addition of DPA-NPs. [ABSTRACT FROM AUTHOR]

An abstract of the article "Synthesis of 4-Quinolones via Triflic Anhydride-Mediated Intramolecular Houben-Hoesch Reaction of ß-Arylamino Acrylonitriles" by authors including C. Wu, P. Huang, and Z. Sun is presented.