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961.
Dr. João Ameixa Dr. Eugene Arthur-Baidoo João Pereira-da-Silva Júlio C. Ruivo Prof. Dr. Márcio T. do N. Varella Prof. Dr. Martin K. Beyer Dr. Milan Ončák Prof. Dr. Filipe Ferreira da Silva Prof. Dr. Stephan Denifl 《Chemphyschem》2022,23(5):e202100834
Ubiquinone molecules have a high biological relevance due to their action as electron carriers in the mitochondrial electron transport chain. Here, we studied the dissociative interaction of free electrons with CoQ0, the smallest ubiquinone derivative with no isoprenyl units, and its fully reduced form, 2,3-dimethoxy-5-methylhydroquinone (CoQ0H2), an ubiquinol derivative. The anionic products produced upon dissociative electron attachment (DEA) were detected by quadrupole mass spectrometry and studied theoretically through quantum chemical and electron scattering calculations. Despite the structural similarity of the two studied molecules, remarkably only a few DEA reactions are present for both compounds, such as abstraction of a neutral hydrogen atom or the release of a negatively charged methyl group. While the loss of a neutral methyl group represents the most abundant reaction observed in DEA to CoQ0, this pathway is not observed for CoQ0H2. Instead, the loss of a neutral OH radical from the CoQ0H2 temporary negative ion is observed as the most abundant reaction channel. Overall, this study gives insights into electron attachment properties of simple derivatives of more complex molecules found in biochemical pathways. 相似文献
962.
Richard Marins da Silva Valeria Monteze Guimarães Lizzy Ayra Alcântara Veríssimo Márcia Cristina Teixeira Ribeiro Vidigal Valéria Paula Rodrigues Minim Luis Antonio Minim 《Journal of separation science》2022,45(2):401-410
This study focused on the extraction, purification, and physicochemical characterization of γ-conglutin, a protein present in lupin seeds with properties of reducing blood glucose levels. Total protein was extracted with an alkaline-saline solvent, followed by isoelectric precipitation. Chromatographic purification of the precipitated fraction was performed using a cation exchange supermacroporous cryogel column. Electrophoresis of the eluted fraction from chromatography presented a single band of ∼48 kDa under non-reducing conditions (two bands of ∼30 and ∼17 kDa, under reducing conditions) confirming the success of the purification protocol. Liquid chromatography-tandem mass spectrometry analysis confirmed the identity of the protein as γ-conglutin. The purified γ-conglutin had an isoelectric point of 7.51, β-sheets prevailing as a secondary structure, and denaturation temperature close to 68°C. The outcome of this work showed that γ-conglutin was obtained with a high degree of purity. The proposed purification protocol is simple and can be easily scaled up. 相似文献
963.
J.?I.?García-GarcíaEmail author M.?A.?Moreno-Frías A.?Vigneron-Tenorio 《Israel Journal of Mathematics》2015,206(1):395-411
We give an algorithm to compute the ω-primality of finitely generated atomic monoids. Asymptotic ω-primality is also studied and a formula to obtain it in finitely generated quasi-Archimedean monoids is proven. The formulation is applied to numerical semigroups, obtaining an expression of this invariant in terms of its system of generators. 相似文献
964.
Özge Pala Dirk J Vriens Jac AM Vennix 《The Journal of the Operational Research Society》2015,66(4):593-601
Escalation of commitment, the tendency of decision makers to keep on investing in losing courses of action, has been shown to be a costly decision bias that affects many areas of decision making. Even though escalation is a widely studied phenomenon, there has been comparatively little research on how to avoid this bias. The present study focuses on de-escalation of commitment and proposes that causal loop diagrams (CLDs) can help to decrease escalating commitment to a failing course of action. By means of an experiment, this study shows that using a CLD decreases escalation tendencies. 相似文献
965.
966.
M.?D.?Ruiz-MedinaEmail author R.?M.?Espejo 《Methodology and Computing in Applied Probability》2015,17(1):207-222
The autoregressive Hilbertian process framework has been introduced in Bosq (2000). This book provides the nonparametric estimation of the autocorrelation and covariance operators of the autoregressive Hilbertian processes. The asymptotic properties of these estimators are also provided. The maximum likelihood approach still remains unexplored. This paper obtains the asymptotic distribution of the maximum likelihood (ML) estimators of the auto-covariance operator of the Hilbert-valued innovation process, and of the autocorrelation operator of a Gaussian autoregressive Hilbertian process of order one. A real data example is analyzed in the financial context for illustration of the performance of the projection maximum likelihood estimation methodology in the context of missing data. 相似文献
967.
Lourenço Beirão da Veiga Gianmarco Manzini Mario Putti 《Numerical Methods for Partial Differential Equations》2015,31(1):336-363
We develop and analyze a post processing technique for the family of low‐order mimetic discretizations based on vertex unknowns for the numerical treatment of diffusion problems on unstructured polygonal and polyhedral meshes. The post processing works in two steps. First, from the nodal degrees of freedom, we reconstruct an elemental‐based vector field that approximates the gradient of the exact solution. Second, we solve a local problem for each mesh vertex associated with a scheme degree of freedom to determine a post processed normal flux that is conservative and divergence preserving. Theoretical results and numerical experiments for two‐dimensional (2D) and 3D benchmark problems show optimal convergence rates. © 2014 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 31: 336–363, 2015 相似文献
968.
969.
Teresa Lopes da Silva Daniela Feijão Alberto Reis 《Applied biochemistry and biotechnology》2010,162(8):2166-2176
Multi-parameter flow cytometry was used to monitor cell intrinsic light scatter, viability, and lipid content of Rhodotorula glutinis CCMI 145 cells grown in shake flasks. Changes in the side light scatter and forward light scatter were detected during the
yeast batch growth, which were attributed to the different yeast growth phases. A progressive increase in the proportion of
cells stained with PI (cells with permeabilized cytoplasmic membrane) was observed during the yeast growth, attaining 79%
at the end of the fermentation. A high correlation between the Nile Red fluorescence intensity measured by flow cytometry
and total lipid content assayed by the traditional gravimetric lipid analysis was found for this yeast, making this method
a suitable and quick technique for the screening of yeast strains for lipid production and optimization of biofuel production
bioprocesses. Medium growth optimization for enhancement of the yeast oil production is now in progress. 相似文献
970.
Ranyere Lucena de Souza José Murillo P. Barbosa Gisella Maria Zanin Marcos Wandir N. Lobão Cleide Mara F. Soares Álvaro Silva Lima 《Applied biochemistry and biotechnology》2010,161(1-8):288-300
The hydrolysis of triglycerides at the oil–water interface, synthesis of esters and transesterification in microaqueous conditions are catalysed by lipase. For its application, a proper purification method was necessary. This study examined the application of an aqueous two-phase system to partition porcine pancreatic lipase. The influence of molecular weight and concentration of polyethylene glycol (PEG), tie line length (TLL), potassium phosphate concentration, sodium chloride (NaCl) addition and temperature in the partition was studied. The enzyme was more efficiently purified in PEG 8,000 at 14.5 °C (PF?=?3.89-fold), presenting more recoveries at the top phase with shorter TLL and lower concentrations of PEG and potassium phosphate. Moreover, the increase of these variables repressed the purification and the further addition of NaCl did not promote the purification of the enzyme. These results demonstrated the efficiency of the aqueous two-phase system on lipase purification. 相似文献