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861.
Paloma Lozano-Picazo Cristina Castro-Domínguez Augusto Luis Bruno Alejandro Baeza Adelia S. Martínez Patricia A. Lpez ngela Castro Yassmin Lakhal Elena Montero Luis Colchero Daniel Gonzlez-Nieto Francisco Javier Rojo Fivos Panetsos Milagros Ramos Rafael Daza Alfonso M. Gan-Calvo Manuel Elices Gustavo Víctor Guinea Jos Prez-Rigueiro 《Molecules (Basel, Switzerland)》2022,27(13)
High-performance regenerated silkworm (Bombyx mori) silk fibers can be produced efficiently through the straining flow spinning (SFS) technique. In addition to an enhanced biocompatibility that results from the removal of contaminants during the processing of the material, regenerated silk fibers may be functionalized conveniently by using a range of different strategies. In this work, the possibility of implementing various functionalization techniques is explored, including the production of fluorescent fibers that may be tracked when implanted, the combination of the fibers with enzymes to yield fibers with catalytic properties, and the functionalization of the fibers with cell-adhesion motifs to modulate the adherence of different cell lineages to the material. When considered globally, all these techniques are a strong indication not only of the high versatility offered by the functionalization of regenerated fibers in terms of the different chemistries that can be employed, but also on the wide range of applications that can be covered with these functionalized fibers. 相似文献
862.
Ali Khorramifar Mansour Rasekh Hamed Karami James A. Covington Sayed M. Derakhshani Jose Ramos Marek Gancarz 《Molecules (Basel, Switzerland)》2022,27(11)
Five potato varieties were studied using an electronic nose with nine MOS sensors. Parameters measured included carbohydrate content, sugar level, and the toughness of the potatoes. Routine tests were carried out while the signals for each potato were measured, simultaneously, using an electronic nose. The signals obtained indicated the concentration of various chemical components. In addition to support vector machines (SVMs that were used for the classification of the samples, chemometric methods, such as the partial least squares regression (PLSR) method, the principal component regression (PCR) method, and the multiple linear regression (MLR) method, were used to create separate regression models for sugar and carbohydrates. The predictive power of the regression models was characterized by a coefficient of determination (R2), a root-mean-square error of prediction (RMSEP), and offsets. PLSR was able to accurately model the relationship between the smells of different types of potatoes, sugar, and carbohydrates. The highest and lowest accuracy of models for predicting sugar and carbohydrates was related to Marfona potatoes and Sprite cultivar potatoes. In general, in all cultivars, the accuracy in predicting the amount of carbohydrates was somewhat better than the accuracy in predicting the amount of sugar. Moreover, the linear function had 100% accuracy for training and validation in the C-SVM method for classification of five potato groups. The electronic nose could be used as a fast and non-destructive method for detecting different potato varieties. Researchers in the food industry will find this method extremely useful in selecting the desired product and samples. 相似文献
863.
The aza-vinylogous Povarov reaction between aromatic amines, α-ketoaldehydes or α-formylesters and α,β-unsaturated dimethylhydrazones was carried out in a sequential three-component fashion under mechanochemical conditions. Following extensive optimization work, the reaction was performed on a vibratory ball mill operating at 20 Hz and using zirconium oxide balls and milling jar, and afforded 1,2,3,4-tetrahydroquinolines and 1,2,3,4-tetrahydro- 1,5-naphthyridines functionalized at C-2, C-4 and also at C-6, in the latter case. This protocol generally afforded the target compounds in good to excellent yields and diastereoselectivities. A comparison of representative examples with the results obtained under conventional conditions revealed that the mechanochemical protocol affords faster Povarov reactions in comparable yields using a solvent-less environment. 相似文献
864.
865.
Nonlinear Dynamics - In this paper, the dynamics of two mechanical oscillators interacting through an asymmetric coupling is considered. In the uncontrolled system, the asymmetry in the coupling... 相似文献
866.
Jesús A. Martín-Illán Sergio Royuela Prof. M. Mar Ramos Prof. José L. Segura Prof. Félix Zamora 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(29):6495-6498
The copper-catalyzed azide–alkyne cycloaddition (CuAAC) click reaction is among the most extensively used strategies for the post-polymerization modification of COFs. This work shows a new procedure for the postsynthetic functionalization of imine-based COFs by using a heterogeneous solid–gas reaction between alkyne-functionalized COFs and azides in the absence of a copper catalyst. This new alternative represents a step forward towards a greener postsynthetic modification of COFs opening a high potential for the development of new applications. 相似文献
867.
Dr. João T. S. Coimbra Dr. Rui P. P. Neves Prof. Dr. Ana V. Cunha Prof. Dr. Maria J. Ramos Prof. Dr. Pedro A. Fernandes 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(42):e202201066
The influence of the dynamical flexibility of enzymes on reaction mechanisms is a cornerstone in biological sciences. In this study, we aim to 1) study the convergence of the activation free energy by using the first step of the reaction catalysed by HIV-1 protease as a case study, and 2) provide further evidence for a mechanistic divergence in this enzyme, as two different reaction pathways were seen to contribute to this step. We used quantum mechanics/molecular mechanics molecular dynamics simulations, on four different initial conformations that led to different barriers in a previous study. Despite the sampling, the four activation free energies still spanned a range of 5.0 kcal ⋅ mol−1. Furthermore, the new simulations did confirm the occurrence of an unusual mechanistic divergence, with two different mechanistic pathways displaying equivalent barriers. An active-site water molecule is proposed to influence the mechanistic pathway. 相似文献
868.
We prove endpoint bounds for derivatives of fractional maximal functions with either smooth convolution kernel or lacunary set of radii in dimensions . We also show that the spherical fractional maximal function maps into a first order Sobolev space in dimensions . 相似文献
869.
Margarida Ramos Paulo Salústio Luísa Serralheiro Fátima Fazão Helena Marques 《Journal of inclusion phenomena and macrocyclic chemistry》2011,70(3-4):407-414
Omeprazole (OME) exhibits low stability to light, heat and humidity. In stress conditions OME stability should improve under inclusion complex form with hydroxypropyl-β-cyclodextrin (HPβCD). Stability of OME, its physical mixture (PM) with HPβCD and OME:HPβCD inclusion complex was assessed during 60 days. The inclusion complexes were prepared by kneading and freeze-drying techniques and characterized by differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). A molecular modelling was also held to predict the most probable tridimensional conformation of inclusion complex OME:HPβCD. The inhibitory activity of free and complexed OME on selected enzymes, namely, papain (protease model of the proton pump) and acetylcholinesterase (enzyme present in cholinergic neurons and also involved in Alzheimer’s disease) was compared. The results obtained show that HPβCD do not protect against OME degradation, in any prepared powder, in the presence of light, heat and humidity. This may indicate that the reactive group of OME is not included in the HPβCD cavity. This fact is supported by molecular modelling data, which demonstrated that 2-pyridylmethyl group of OME is not included into the cyclodextrin cavity. In relation to enzymatic assays it was observed that free OME and OME in the binary systems showed identical inhibitory activity on papain and acethylcolinesterase, concluding that HPβCD do not affect OME activity on these two enzymes. 相似文献
870.
Bet Camila Delinski de Oliveira Cristina Soltovski Colman Tiago André Denck Bisinella Radla Zabian Bassetto Beninca Cleoci Lacerda Luiz Gustavo Ramos Augusto Pumacahua Schnitzler Egon 《Journal of Thermal Analysis and Calorimetry》2019,138(4):2733-2749
Journal of Thermal Analysis and Calorimetry - The aim of this study was to characterise the organic amaranth flour (Amaranthus caudatus), native starch and by-products generated after its aqueous... 相似文献