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91.
Lerma-García MJ Lusardi R Chiavaro E Cerretani L Bendini A Ramis-Ramos G Simó-Alfonso EF 《Journal of chromatography. A》2011,1218(42):7521-7527
A method for the determination of triacylglycerols (TAGs) in vegetable oils from different botanical origins by HPLC with UV-vis detection has been developed. Using a core-shell particle packed column (C18, 2.6 μm), TAG separation was optimized in terms of mobile phase composition and column temperature. Using isocratic elution with acetonitrile/n-pentanol at 10 °C, excellent efficiency with good resolution between most of the TAG peak pairs, within a total analysis time of 15 min, was achieved. Using mass spectrometry detection, a total of 15 peaks, which were common to oils of six different botanical origins (corn, extra virgin olive, grapeseed, hazelnut, peanut and soybean) were identified. These peaks were used to construct linear discriminant analysis (LDA) models for botanical origin prediction. Ratios of the peak areas selected by pairs were used as predictors. All the oils were correctly classified with assignment probabilities higher than 95%. 相似文献
92.
Fuentes de Arriba Á Turiel MG Simón L Sanz F Boyero JF Muñiz FM Morán JR Alcázar V 《Organic & biomolecular chemistry》2011,9(24):8321-8327
Carbazole-based receptors functionalized with two sulfonamide groups have been synthesized and their properties as anion receptors have been evaluated. The receptor with bis(trifluoromethyl)aniline groups has shown a very high affinity for halide ions, especially remarkable as only two hydrogen bonds are formed in the complexes. (1)H NMR and fluorescence titrations have been carried out and binding constants up to 7.9 × 10(6) M(-1) have been reached. X-ray structures have been obtained and a modelling study has shown the possible reasons for the large affinity of these compounds for halide anions. 相似文献
93.
Solid-phase extraction combined with dispersive liquid-liquid microextraction (SPE-DLLME) was applied for the extraction of six organophosphorous pesticides (OPPs) in water samples. The analytes considered in this study were determined by gas chromatography with mass spectrometry and included prophos, diazinon, chlorpyrifos methyl, methyl parathion, fenchlorphos and chlorpyrifos. Several extraction conditions (extraction solvent and elution/dispersion solvents nature, extraction solvent volume, elution solvent volume, water volume and sample volume) were tested for SPE-DLLME with these analytes and the best results were obtained using carbon tetrachloride as the extraction solvent and acetone as the elution/dispersion solvent. Calibration curves for the determination of OPPs in water samples were constructed in the concentration range of 10-100 ng/L. Limits of detection (LODs) ranged from 38 to 230 pg/L values that are below the maximum admissible level for drinking water (100 ng/L). Relative standard deviations (RSD) were between 8.6 and 10.4% for a fortification level of 100 ng/L. At the same fortification level, the relative recoveries (R.R.) of tap, well and irrigation water samples were in the range of 30.2-97.1%. 相似文献
94.
Kuma S Nakahara H Tsubouchi M Takahashi A Mustafa M Sim G Momose T Vilesov AF 《The journal of physical chemistry. A》2011,115(25):7392-7399
Clusters of tetracene molecules with different numbers of attached (Ar)(N), (Ne)(N) and (H(2))(N) particles (N = 1-2000) are assembled inside superfluid He nanodroplets and studied via laser-induced fluorescence. The frequency shift of the fluorescence spectrum of the tetracene molecules is studied as a function of cluster size and pickup order of tetracene and cluster species. For (Ar)(N) and (Ne)(N) clusters, our results indicate that the tetracene molecules reside inside the clusters when tetracene is captured by the He nanodroplet before the cluster species; conversely, the tetracene molecules stay on the surface of the clusters when tetracene is captured after the cluster species. In the case of (H(2))(N) clusters, however, tetracene molecules reside inside the (H(2))(N) clusters irrespective of the pickup order. We conclude that (Ar)(N) and (Ne)(N) clusters are rigid at T = 0.38 K, while (H(2))(N) clusters of up to N = 2000 remain fluxional at the same temperature. The results may also indicate the occurrence of heterogeneous nucleation of the (H(2))(N) clusters, which is induced by the interaction with tetracene chromophore molecules. 相似文献
95.
Rangel TB Assreuy AM Pires Ade F Carvalho AU Benevides RG Simões Rda C Silva HC Bezerra MJ Nascimento AS Nascimento KS Nagano CS Sampaio AH Delatorre P Rocha BA Fernandes PM Cavada BS 《Molecules (Basel, Switzerland)》2011,16(6):5087-5103
DwL, a lectin extracted from the seeds of Dioclea wilsonii, is a metalloprotein with strong agglutinating activity against rabbit and ABO erythrocytes, inhibited by glucose and mannose. DwL was purified by affinity chromatography on a Sephadex G-50 column and ion exchange chromatography on a HiTrap SP XL column. SDS-PAGE revealed three electrophoretic bands corresponding to the α (25,634 ± 2 Da), β (12,873 ± 2 Da) and γ (12,779 ± 2 Da) chains. Protein sequencing was done by Tandem Mass Spectrometry. The primary sequence featured 237 amino acids and was highly homologous to other reported Diocleinae lectins. A complete X-ray dataset was collected at 2.0 ? for X-Man-complexed DWL crystals produced by the vapor diffusion method. The crystals were orthorhombic and belonged to the space group I222, with the unit-cell parameters a = 59.6, b = 67.9 and c = 109.0 ?. DWL differed in potency from other ConA-like lectins and was found to induce neutrophil migration in rats, making it particularly useful in structural/functional studies of this class of proteins. 相似文献
96.
97.
Hanseok Yi Dr. Suhwan Song Sang Myeong Han Jieun Lee Prof. Dr. Woojae Kim Prof. Dr. Eunji Sim Prof. Dr. Dongil Lee 《Angewandte Chemie (International ed. in English)》2023,62(33):e202302591
We report a new strategy in which a thiolate-protected Ag25 nanocluster can be doped with open d-shell group 8 (Ru, Os) and 9 (Ir) metals by forming metal hydride (RuH2, OsH2, IrH) superatoms with a closed d-shell. Structural analyses using various experimental and theoretical methods revealed that the Ag25 nanoclusters were co-doped with the open d-shell metal and hydride species to produce superatom-in-superatom nanoclusters, establishing a novel superatom doping phenomenon for open d-shell metals. The synthesized superatom-in-superatom nanoclusters exhibited dopant-dependent photoluminescence (PL) properties. Comparative PL lifetime studies of the Ag25 nanoclusters doped with 8–10 group metals revealed that both radiative and nonradiative processes were significantly dependent on the dopant. The former is strongly correlated with the electron affinity of the metal dopant, whereas the latter is governed predominantly by the kernel structure changed upon the doping of the metal hydride(s). 相似文献
98.
Jong Seung Kim Moon Hwan Cho Sang Chul Lee Kyung Bok Lee Wonbo Sim Jae Hyung Yoo 《Microchemical Journal》1998,60(3):282-289
The mole transport rate of alkaline earth metal ions through a bulk liquid membrane and a supported liquid membrane using a series of proton diionizable acyclic polyethers was measured. Among alkaline earth metal ions, the calcium ion was observed to be selectively transported in both single and competitive transport experiments. Potentiometric titration and solution calorimetric titration also gave calcium selectivity over other alkaline earth metal ions. Acyclic polyether bearing a diethylene glycol unit andn-tetradecyl lipophilic chain at the α position of carboxylic acid affords the best selectivity for the calcium ion in bulk and supported liquid membranes. 相似文献
99.
Howard Yi Fan Sim Jaslyn Ru Ting Chen Charlynn Sher Lin Koh Dr. Hiang Kwee Lee Dr. Xuemei Han Gia Chuong Phan-Quang Jing Yi Pang Dr. Chee Leng Lay Dr. Srikanth Pedireddy Dr. In Yee Phang Prof. Edwin Kok Lee Yeow Prof. Xing Yi Ling 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(39):17145-17151
The electrochemical nitrogen reduction reaction (NRR) offers a sustainable solution towards ammonia production but suffers poor reaction performance owing to preferential catalyst–H formation and the consequential hydrogen evolution reaction (HER). Now, the Pt/Au electrocatalyst d-band structure is electronically modified using zeolitic imidazole framework (ZIF) to achieve a Faradaic efficiency (FE) of >44 % with high ammonia yield rate of >161 μg mgcat−1 h−1 under ambient conditions. The strategy lowers electrocatalyst d-band position to weaken H adsorption and concurrently creates electron-deficient sites to kinetically drive NRR by promoting catalyst–N2 interaction. The ZIF coating on the electrocatalyst doubles as a hydrophobic layer to suppress HER, further improving FE by >44-fold compared to without ZIF (ca. 1 %). The Pt/Au-NZIF interaction is key to enable strong N2 adsorption over H atom. 相似文献
100.
Dongjoon Lee Jong-Chan Park Keum Sim Jung Jiyeong Kim Ji Sung Jang Sunghoon Kwon Min Soo Byun Dahyun Yi Gihwan Byeon Gijung Jung Yu Kyeong Kim Dong Young Lee Sun-Ho Han Inhee Mook-Jung 《Experimental & molecular medicine》2022,54(1):61
The deposition of beta-amyloid (Aβ) in the brain precedes the onset of symptoms such as cognitive impairment in Alzheimer’s disease (AD); therefore, the early detection of Aβ accumulation is crucial. We previously reported the applicability of the QPLEXTM Alz plus assay kit for the prescreening of Aβ accumulation. Here, we tested the specific application of the kit in a large cohort of cognitively normal (CN) individuals of varying ages for the early detection of Aβ accumulation. We included a total of 221 CN participants with or without brain Aβ. The QPLEXTM biomarkers were characterized based on age groups (1st–3rd tertile) and across various brain regions with cerebral amyloid deposition. The 3rd tertile group (>65 years) was found to be the most suitable age group for the application of our assay kit. Receiver operating characteristic curve analysis showed that the area under the curve (AUC, discrimination power) was 0.878 with 69.7% sensitivity and 98.4% specificity in the 3rd tertile group. Additionally, specific correlations between biomarkers and cerebral amyloid deposition in four different brain regions revealed an overall correlation with general amyloid deposition, consistent with previous findings. Furthermore, the combinational panel with plasma Aβ1–42 levels maximized the discrimination efficiency and achieved an AUC of 0.921 with 95.7% sensitivity and 67.3% specificity. Thus, we suggest that the QPLEXTM Alz plus assay is useful for prescreening brain Aβ levels in CN individuals, especially those aged >65 years, to prevent disease progression via the early detection of disease initiation.Subject terms: Alzheimer''s disease, Neural ageing, ELISA 相似文献