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61.
Pietrzyk Kyle Korneev Svyatoslav Behandish Morad Battiato Ilenia 《Transport in Porous Media》2021,140(1):313-349
Transport in Porous Media - Macroscopic differential equations that accurately account for microscopic phenomena can be systematically generated using rigorous upscaling methods. However, such... 相似文献
62.
Hydrogenation of CO2‐Derived Carbonates and Polycarbonates to Methanol and Diols by Metal–Ligand Cooperative Manganese Catalysis 下载免费PDF全文
M. Sc. Viktoriia Zubar Dr. Yury Lebedev Dr. Luis Miguel Azofra Prof. Dr. Luigi Cavallo Dr. Osama El‐Sepelgy Prof. Dr. Magnus Rueping 《Angewandte Chemie (International ed. in English)》2018,57(41):13439-13443
The first base‐metal‐catalysed hydrogenation of CO2‐derived carbonates to alcohols is presented. The reaction proceeds under mild conditions in the presence of a well‐defined manganese complex with a loading as low as 0.25 mol %. The non‐precious‐metal homogenous catalytic system provides an indirect route for the conversion of CO2 into methanol with the co‐production of value‐added (vicinal) diols in yields of up to 99 %. Experimental and computational studies indicate a metal–ligand cooperative catalysis mechanism. 相似文献
63.
Morad Chadni Amandine L. Flourat Valentin Reungoat Louis M. M. Mouterde Florent Allais Irina Ioannou 《Molecules (Basel, Switzerland)》2021,26(1)
The aim of this paper is to study the effect of the pH on the extraction of sinapic acid and its derivatives from mustard seed meal. Solutions of acidic pH (pH 2), basic pH (pH 12) and distilled water (uncontrolled pH ~ 4.5) were tested at different percentages of ethanol. The maximum extraction yield for sinapic acid (13.22 µmol/g of dry matter (DM)) was obtained with a buffered aqueous solution at pH 12. For ethyl sinapate, the maximum extraction yield reached 9.81 µmol/g DM with 70% ethanol/buffered aqueous solution at pH 12. The maximum extraction yield of sinapine (15.73 µmol/g DM) was achieved with 70% ethanol/buffered aqueous solution at pH 2. The antioxidant activity of each extract was assessed by DPPH assay; the results indicated that the extracts obtained at pH 12 and at low ethanol percentages (<50%) exhibit a higher antioxidant activity than extracts obtained at acidic conditions. Maximum antioxidant activity was reached at pH 12 with buffer solution (11.37 mg of Trolox Equivalent/g DM), which confirms that sinapic acid-rich fractions exhibit a higher antioxidant activity. Thus, to obtain rich antioxidant extracts, it is suggested to promote the presence of sinapic acid in the extracts. 相似文献
64.
Mehri Ghazaghi Hassan Zavvar Mousavi Ali Morad Rashidi Hamid Shirkhanloo Reza Rahighi 《Analytica chimica acta》2016
A uniquely novel, fast, and facile technique is introduced for the first time in which a scant amount of graphene oxide (GO), without modification, has been utilized in dispersive mode of solid phase extraction (SPE) for an efficient yet simple separation. The proposed method of coagulating homogenous dispersive micro solid phase extraction (CHD-µSPE) is based on coagulation of homogeneous GO solution with the aid of polyetheneimine (PEI). CHD-µSPE use full adsorption capacity of GO because in this method was used GO solution obtained from synthesis process without drying step and stacking nanosheets. In optimized condition, 30 µL GO solution (7 mg mL−1), obtained in synthesis process, was injected into 1.5 mL the sample solution followed by immediate injection of 53 µL PEI solution (1 mg mL−1). After inserting PEI, GO sheets aggregate and can be readily separated by centrifugation. PEI not only cause aggregation of GO, but also form three-dimensional network of GO with easy handling in following separation steps. Lead, cadmium, and chromium were selected as model analytes and the effecting parameters including the amount of GO, concentration of PEI, sample pH, extraction time, and type of desorption solvent were investigated and optimized. The results indicate that the proposed CHD-µSPE method can be successfully applied GO in dispersive mode of SPE without effecting on good capability adsorption of GO. The novel method was applied in determination of lead, cadmium, and chromium in water, human saliva, and urine samples by electrothermal atomic absorption spectrometry. The detection limits are as low as 0.035, 0.005, and 0.012 µg L−1 for Pb, Cd, and Cr respectively. The intra-day precisions (RSDs) were lower than 3.8%. CHD-µSPE method showed a good linear ranges of 0.24–15.6, 0.015–0.95 and 0.039–2.33 µg L−1 for Pb, Cd and Cr respectively. Method performance was investigated by determination of mentioned metal ions in river water, human urine and saliva sample with good recoveries in range of 94.2–103.0%. The accuracy of the method was underpinned by correct analysis of a standard reference material (SRM: 2668 level I, Urine). 相似文献
65.
A. Ravikumar P. Panneerselvam K. Radhakrishnan Norhashimah Morad C. D. Anuradha S. Sivanesan 《Journal of fluorescence》2017,27(6):2101-2109
A label -free DNAzyme amplified biosensor is found to be highly selective and sensitive towards fluorescent detection of Pb2+ ions in aqueous media. The DNAzyme complex has designed by the hybridization of the enzyme and substrate strand. In the presence of Pb2+, the DNAzyme activated and cleaved the substrate strand of RNA site (rA) into two oligonucleotide fragments. Further, the free fragment was hybridized with a complementary strand on the surface of MBs. After magnetic separation, SYBER Green I was added and readily intercalate with the dsDNA to gives a bright fluorescence signal with intensity directly proportional to the concentration of Pb2+ions. A detection limit of 5 nM in Pb2+ the detection range 0 to 500 nM was obtained. This label- free fluorescent biosensor has been successfully applied to the determination of environmental water samples. Then results open up the possibility for real-time quantitative detection of Pb2+ with convenient potential applications in the biological and environmental field. 相似文献
66.
Reproducible specific heat capacities (C p) of triglycerides can be obtained by using heat-flux DSC under improved operating conditions. The improved operating parameters, such as the scanning rate, the sample mass and the atmosphere within the DSC chamber, were established via statistical analysis of the experimental data with trilaurin as a sample. The specific heat capacity results on trilaurin were compared with the values calculated by using estimation methods. The precision of the specific heat capacity measured for trilaurin under these conditions was within ±1%. 相似文献
67.
Dziuba D Postupalenko VY Spadafora M Klymchenko AS Guérineau V Mély Y Benhida R Burger A 《Journal of the American Chemical Society》2012,134(24):10209-10213
With the aim of developing a new tool to investigate DNA interactions, a nucleoside analogue incorporating a 3-hydroxychromone (3HC) fluorophore as a nucleobase mimic was synthesized and incorporated into oligonucleotide chains. In comparison with existing fluorescent nucleoside analogues, this dye features exceptional environmental sensitivity switching between two well-resolved fluorescence bands. In labeled DNA, this nucleoside analogue does not alter the duplex conformation and exhibits a high fluorescence quantum yield. This probe is up to 50-fold brighter than 2-aminopurine, the fluorescent nucleoside standard. Moreover, the dual emission is highly sensitive to the polarity of the environment; thus, a strong shielding effect of the flanking bases from water was observed. With this nucleoside, the effect of a viral chaperone protein on DNA base stacking was site-selectively monitored. 相似文献
68.
Bogdan M. Benin Kyle M. McCall Michael Wrle Viktoriia Morad Marcel Aebli Sergii Yakunin Yevhen Shynkarenko Maksym V. Kovalenko 《Angewandte Chemie (International ed. in English)》2020,59(34):14490-14497
Low‐dimensional ns2‐metal halide compounds have received immense attention for applications in solid‐state lighting, optical thermometry and thermography, and scintillation. However, these are based primarily on the combination of organic cations with toxic Pb2+ or unstable Sn2+, and a stable inorganic luminescent material has yet to be found. Here, the zero‐dimensional Rb7Sb3Cl16 phase, comprised of isolated [SbCl6]3? octahedra and edge‐sharing [Sb2Cl10]4? dimers, shows room‐temperature photoluminescence (RT PL) centered at 560 nm with a quantum yield of 3.8±0.2 % at 296 K (99.4 % at 77 K). The temperature‐dependent PL lifetime rivals that of previous low‐dimensional materials with a specific temperature sensitivity above 0.06 K?1 at RT, making it an excellent thermometric material. Utilizing both DFT and chemical substitution with Bi3+ in the Rb7Bi3?3xSb3xCl16 (x≤1) family, we present the edge‐shared [Sb2Cl10]4? dimer as a design principle for Sb‐based luminescent materials. 相似文献
69.
Mangiacapra Gennaro Wittal Matthew Capello Elisa Nazari Morad 《Nonlinear dynamics》2022,108(3):2127-2146
Nonlinear Dynamics - This paper presents a novel rigid-body navigation and control architecture within the framework of special Euclidean group $$\mathsf {SE(3)}$$ and its tangent bundle $$\mathsf... 相似文献
70.
Theoretical calculations of g-tensor components for the spin–orbit quartet, which arises as the ground state in three-coordinate d9 complexes and low-spin d7 complexes of D3h symmetry, have been made on the assumption that the spin–orbit interaction is commensurable with the electron-vibrational interaction. The calculations were carried out within the framework of crystal field theory using representations of the hole formalism. The analytical expressions for g-tensor components were obtained limited to first-order terms. It was shown that the account of the electron–vibrational interaction in the excited quartet only provides three-axial anisotropy for the g-tensor. It was shown that the g-tensor rotates in the plane of the three-coordinate structure with consensual motion of the atoms. The resulting expressions for the g-factor components are in good agreement with experimental data. Being universal for a wide range of contributions of the vibronic and spin–orbit interactions, these expressions essentially fill the gap in studying structures of coordination compounds. 相似文献