1,836 research outputs found
Recommended from our members
Sequence-Dependent Guest Release Triggered by Orthogonal Chemical Signals.
Three Zn(II)4L4 coordination cages, assembled from trisiminopyridine ligands, exhibit differences in their guest-binding selectivities and reactivity with tris(2-aminoethyl)amine (tren), which enabled the design of a molecular network that responded in distinct ways to different chemical signals. When two of these cages were present in solution together, one of them was observed to selectively encapsulate chloroform, and the other was observed to selectively encapsulate cyclohexane. The two guests could be released sequentially, in a specified order defined by the input of two separate chemical signals: tren and perrhenate. Furthermore, the observed reactivity of tren with the initial cage mixture provided control over the uptake and release of perrhenate within the third cage formed in situ. One of these tetrahedral cages has been identified as a tight (K(a) > 10(7) M(-1)) and selective host for perrhenate, an anion of great physicochemical similarity to pertechnetate, both having uses in nuclear medicine.This work was supported by the European Research Council. We thank Diamond Light Source (UK) for synchrotron beamtime on I19 (MT8464) and Dr. Rana A. Bilbeisi for a preliminary screening of guests for cage 1.This is the author accepted manuscript. The final version is available from the American Chemical Society via http://dx.doi.org/10.1021/jacs.5b1301
The adoption of corporate social responsibility active learning methodology with management accounting students
The aim of this paper is to integrate active methodology on corporate social responsibility (CSR) learning into management accounting studies. The linkages between sustainable management and management accounting demand those future managers integrate CSR into their training in an effective way, as they will become change agents for CSR. A representative sample of students at the University of Jaen has been selected in order to adopt CSR active learning, which allows us to draw conclusions about how they perceive CSR and its management. Qualitative methodology has been integrated in this project-based learning using flipped classroom. Our evidence full supports the validity of the CSR active learning methodology to create an effective learning context that involves professional and emotional competences, as the answers offered mainly included some relevant topics covered by CSR research and social and environmental accounting (SEA). This study contributes to previous literature assessing the potential of active methodologies in CSR learning. Also, it provides important insights for university and business school managers to design or modify curricula that are related to management accounting in line with sustainabilit
Helical static mixer simulations for its integration in the pour plate method: mixing agar and a nutrient solution
In microbiology laboratories, it is essential to obtain high-quality samples where the culture media are completely homogeneous. The pour plate method includes having to melt the culture media—a mixture of agar and a nutrient solution—before seeding. A static mixer is designed for this purpose, employing CFD (Computational Fluid Dynamics) with the software OpenFOAM to simulate the fluid’s behaviour in a helical static mixer with both internal and external configurations. The objective is to validate the CFD model by comparing it with the literature and provide a first approach to the mixer design. After satisfactory validation of the model, the results of the initial designs for Reynolds number 14 reveal the notably different behaviour of the fluids during mixing due to their differing properties, since agar and the nutrient solution present a high viscosity ratio. While the mixing efficiency is similar for the internal and external mixers, improved performance is demonstrated in the internal mixer, even for a shorter version. The external version of the mixer reaches a value for a mixing efficiency of 0.89 whereas the internal version performs more homogeneous mixing for the same number of mixing elements. This evaluation is based on a simplified internal design for computational simulations, whereas the external mixer is easier to manufacture but more complex to implement computationally. Finally, homogeneous mixing is achieved for the internal mixer configuration when adjusting its dimensions to those available on the marketThis research was funded by Doctorats Industrials from Generalitat de Catalunya grant number 2021 DI 42. The APC was funded by Doctorats Industrials from Generalitat de CatalunyaPostprint (published version
Recommended from our members
An L-proline based thermoresponsive and pH-switchable nanogel as a drug delivery vehicle
The synthesis and characterisation of a novel dual stimuli-responsive nanogel, based on thermoresponsive N-n-propylacrylamide and an L-proline based monomer acting as a pH-switcher, is reported here. The effect of the crosslinker/co-monomer ratios was studied to demonstrate the relationship between the chemical structure, degree of hydrophobicity and physico-chemical characteristics of the nanogels. Tailoring of the thermoresponsive properties was achieved by altering crosslinker N,N′-methylenebis(acrylamide) content between 10 and 50 mol%, in combination with three thermoresponsive monomers N-n-isopropylacrylamide, N-n-propylacrylamide and N-acryloylpyrrolidine. A library of 25 different combinations of monomers and crosslinkers was obtained and characterised by dynamic light scattering and UV-Vis spectroscopy. The nanogel based on N-n-propylacrylamide and 10 mol% crosslinker was then co-polymerised with an L-proline based monomer to introduce a pH-switch. This nanogel was obtained with <10 nm particle size and a VPTT ca. 43 °C, and was used to demonstrate a drug delivery capability using Nile Blue A as a model drug. Detailed studies demonstrated maximum drug release at lower pH and 43 °C, thus confirming the dual stimuli switch
Recommended from our members
Synthesis and binding studies of two new macrocyclic receptors for the stereoselective recognition of dipeptides
We present here the design, synthesis, and analysis of a series of receptors for peptide ligands inspired by the hydrogen-bonding pattern of protein β-sheets. The receptors themselves can be regarded as strands 1 and 3 of a three-stranded β-sheet, with cross-linking between the chains through the 4-position of adjacent phenylalanine residues. We also report on the conformational equilibria of these receptors in solution as well as on their tendency to dimerize. 1H NMR titration experiments are used to quantify the dimerization constants, as well as the association constant values of the 1:1 complexes formed between the receptors and a series of diamides and dipeptides. The receptors show moderate levels of selectivity in the molecular recognition of the hydrogen-bonding pattern present in the diamide series, selecting the α-amino acid-related hydrogen-bonding functionality. Only one of the two cyclic receptors shows modest signs of enantioselectivity and moderate diastereoselectivity in the recognition of the enantiomers and diastereoisomers of the Ala-Ala dipeptide (ΔΔG01 (DD-DL) = −1.08 kcal/mol and ΔΔG01 (DD-LD) = −0.89 kcal/mol). Surprisingly, the linear synthetic precursors show higher levels of stereoselectivity than their cyclic counterparts
Validez del Ages & Stages questionnaires para predecir el desempeño cognitivo en los primeros años de educación escolar
ResumenIntroducciónEl Ages and Stages questionnaires (ASQ) fue validado en nuestro país para el tamizaje del desarrollo psicomotor. El objetivo es evaluar la validez del ASQ para predecir un menor rendimiento cognitivo en los primeros años de educación escolar.Pacientes y métodoEstudio de pruebas diagnósticas en una muestra de niños de nivel socioeconómico medio alto evaluados previamente con ASQ a los 8, 18 y/o 30 meses, y luego con la Escala de inteligencia para niños de Wechsler-tercera edición (WISC-III) entre los 6 y 9 años de edad. Cada evaluación con ASQ se contabilizó en forma independiente. La Escala de WISC-III fue estandarizada para la muestra, considerando rendimiento bajo cuando el puntaje total estaba bajo una desviación estándar de la media.ResultadosSe incluyeron 123 niños, correspondientes a 174 evaluaciones ASQ (42 de 8; 55 de 18; 77 de 30 meses de edad). El área bajo la curva ROC fue 80,7%, siendo superior a los 8 meses (98,0%) que a los 18 y 30 meses (78,1 y 79,3%, respectivamente). Considerando distintos criterios de corte con ASQ se obtuvo sensibilidad baja (27,8% a 50,0%), pero especificidad elevada (78,8% a 96,2%); el valor predictivo positivo varió entre 21,4% y 45,5%, mientras que el valor predictivo negativo fue 92,0-93,2%.ConclusiónEl ASQ tiene baja sensibilidad pero excelente especificidad para predecir un menor rendimiento cognitivo durante los primeros años de educación escolar, siendo una buena alternativa para monitorizar el desarrollo psicomotor de niños que se atienden en el sector privado de salud de nuestro país.AbstractIntroductionThe Ages and Stages questionnaires (ASQ) has been recently validated in our country for developmental screening. The objective of this study is evaluate the validity of ASQ to predict low cognitive performance in the early years of schooling.Patients and methodDiagnostic test studies conducted on a sample of children of medium-high socioeconomic level were evaluated using ASQ at least once at 8, 18 and/or 30 months old, and later, between 6 and 9 years old, reevaluated using the Wechsler Intelligence Scale for Children-third edition (WISC-III). Each ASQ evaluation was recorded independently. WISC-III was standardized, considering underperformance when the total score were under -1 standard deviationResults123 children, corresponding to 174 ASQ assessments (42 of them were 8 months old, 55 were 18 months and 77 were 30 months of age) were included. An area under the ROC curve of 80.7% was obtained, showing higher values at 8 months (98.0%) compared to 18 and 30 months old (78.1 and 79.3%, respectively). Considering different ASQ scoring criteria, a low sensitivity (27.8 to 50.0%), but a high specificity (78.8 to 96.2%) were obtained; the positive predictive value ranged between 21 and 46%, while the negative value was 92.0-93.2%.ConclusionASQ has low sensitivity but excellent specificity to predict a low cognitive performance during the first years of schooling, being a good alternative to monitor psychomotor development in children who attend the private sector healthcare in our country
Classroom learning and the perception of social responsibility amongst graduate students of management accounting
This study analyzes how learning about social responsibility (SR) can modify the perceptions of university students about the importance of responsible behavior on the part of companies. To this end, a questionnaire was designed and administered to Management Accounting students before (n = 128) and after (n = 71) receiving two training activities on SR. The descriptive results obtained testify to the importance of SR in the views of the sampled students, both before and after receiving the specific learning in SR. In this latter moment, students demonstrated a vision highly committed to the need for SR to be part of the economic agenda. The results also show that there was a significant change in the perception of SR and its implications in terms of benefits and costs before and after receiving the training. All of this suggests that SR training has partially modified students’ perceptions of SR. This paper provides important insights that could be leveraged by university and business school managers for the purpose of designing or modifying curricula related to SR. At the same time, it evaluates the potential of SR learning as a tool for modifying attitudes.Proyecto de Innovación Docente de la Universidad de Jaén “Active learning of Social Responsibility
within the Management Accounting subjects”, I2D-UJA 2016–201
Covalently Crosslinked Nanogels: An NMR Study of the Effect of Monomer Reactivity on Composition and Structure
Covalently crosslinked nanogels are widely explored as drug delivery systems and sensors. Radical polymerization provides a simple, inexpensive, and broadly applicable approach for their preparation, although the random nature of the reaction requires careful study of the final chemical composition. We demonstrate how the different reactivities of the monomers influence the total degree of incorporation into the polymer matrix and the role played by the experimental parameters in maximizing polymerization efficiency. Nanogels based on N-isopropylacrylamide, N-n-propylacrylamide, and acrylamide crosslinked with N,N’-methylenebisacrylamide were included in this study, in combination with functional monomers N-acryloyl-l-proline, 2-acrylamido-2-methyl-1-propanesulfonic acid, and 4-vinyl-1H-imidazole. Total monomer concentration and initiator quantities are determining parameters for maximizing monomer conversions and chemical yields. The results show that the introduction of functional monomers, changes in the chemical structure of the polymerizable unit, and the addition of templating molecules can all have an effect on the polymerization kinetics. This can significantly impact the final composition of the matrices and their chemical structure, which in turn influence the morphology and properties of the nanogels
Recommended from our members
Covalently crosslinked nanogels: an NMR study of the effect of monomer reactivity on composition and structure
Covalently crosslinked nanogels are widely explored as drug delivery systems and sensors. Radical polymerization provides a simple, inexpensive, and broadly applicable approach for their preparation, although the random nature of the reaction requires careful study of the final chemical composition. We demonstrate how the different reactivities of the monomers influence the total degree of incorporation into the polymer matrix and the role played by the experimental parameters in maximizing polymerization efficiency. Nanogels based on N-isopropylacrylamide, N-n-propylacrylamide, and acrylamide crosslinked with N,N’-methylenebisacrylamide were included in this study, in combination with functional monomers N-acryloyl-l-proline, 2-acrylamido-2-methyl-1-propanesulfonic acid, and 4-vinyl-1H-imidazole. Total monomer concentration and initiator quantities are determining parameters for maximizing monomer conversions and chemical yields. The results show that the introduction of functional monomers, changes in the chemical structure of the polymerizable unit, and the addition of templating molecules can all have an effect on the polymerization kinetics. This can significantly impact the final composition of the matrices and their chemical structure, which in turn influence the morphology and properties of the nanogels
Wilms Tumor 1b Expression Defines a Pro-regenerative Macrophage Subtype and Is Required for Organ Regeneration in the Zebrafish
Organ regeneration is preceded by the recruitment of innate immune cells, which play an active role during repair and regrowth. Here, we studied macrophage subtypes during organ regeneration in the zebrafish, an animal model with a high regenerative capacity. We identified a macrophage subpopulation expressing Wilms tumor 1b (wt1b), which accumulates within regenerating tissues. This wt1b+ macrophage population exhibited an overall pro-regenerative gene expression profile and different migratory behavior compared to the remainder of the macrophages. Functional studies showed that wt1b regulates macrophage migration and retention at the injury area. Furthermore, wt1b-null mutant zebrafish presented signs of impaired macrophage differentiation, delayed fin growth upon caudal fin amputation, and reduced cardiomyocyte proliferation following cardiac injury that correlated with altered macrophage recruitment to the regenerating areas. We describe a pro-regenerative macrophage subtype in the zebrafish and a role for wt1b in organ regeneration.A.B.G.-R. is supported by the Sara Borrell Program (CD11/00165) and CIBER de Enfermedades Cardiovasculares (CB16/11/00286). H.R. was supported by a short-term EMBO fellowship (EMBOSTF7204). I.J.M. was supported by a Marie-Sklodowska-Curie postdoctoral fellowship (PIEF-GA-2012-330728). N.M. is supported by Swiss National Science Foundation grant 31003A_15972 and the European Research Council (starting grant 337703–zebra–Heart). The CNIC is supported by the Instituto de Salud Carlos III (ISCIII), the Ministerio de Ciencia, Innovacio´ n, y Universidades (MCNU), and the Pro CNIC Foundation
AGRADECIENTOS: ProCNIC; Severo Ochoa (SEV-2015-0505)S
- …