Bilberry xyloglucan—novel building blocks containing β-xylose within a complex structure

2007 ◽  
Vol 342 (2) ◽  
pp. 170-181 ◽  
Author(s):  
Hauke Hilz ◽  
Laura E. de Jong ◽  
Mirjam A. Kabel ◽  
René Verhoef ◽  
Henk A. Schols ◽  
...  
Keyword(s):  
Complex Structure ◽  
Building Blocks

scholarly journals Playing with covalent triazine framework tiles for improved CO2 adsorption properties and catalytic performance

2019 ◽  
Vol 10 ◽  
pp. 1217-1227 ◽  
Author(s):  
Giulia Tuci ◽  
Andree Iemhoff ◽  
Housseinou Ba ◽  
Lapo Luconi ◽  
Andrea Rossin ◽  
...  
Keyword(s):  
Carbon Capture ◽  
Rational Design ◽  
Gas Adsorption ◽  
Ambient Pressure ◽  
Complex Structure ◽  
Building Blocks ◽  
Catalytic Performance ◽  
High Specific Surface Area ◽  
Morphological Properties ◽  
Design And Synthesis

The rational design and synthesis of covalent triazine frameworks (CTFs) from defined dicyano-aryl building blocks or their binary mixtures is of fundamental importance for a judicious tuning of the chemico-physical and morphological properties of this class of porous organic polymers. In fact, their gas adsorption capacity and their performance in a variety of catalytic transformations can be modulated through an appropriate selection of the building blocks. In this contribution, a set of five CTFs (CTF1–5) have been prepared under classical ionothermal conditions from single dicyano-aryl or heteroaryl systems. The as-prepared samples are highly micro-mesoporous and thermally stable materials featuring high specific surface area (up to 1860 m2·g−1) and N content (up to 29.1 wt %). All these features make them highly attractive samples for carbon capture and sequestration (CCS) applications. Indeed, selected polymers from this series rank among the CTFs with the highest CO2 uptake at ambient pressure reported so far in the literature (up to 5.23 and 3.83 mmol·g−1 at 273 and 298 K, respectively). Moreover, following our recent achievements in the field of steam- and oxygen-free dehydrogenation catalysis using CTFs as metal-free catalysts, the new samples with highest N contents have been scrutinized in the process to provide additional insights to their complex structure–activity relationship.

scholarly journals 15N NMR Shifts of Eumelanin Building Blocks in Water: A Combined Quantum Mechanics/Statistical Mechanics Approach

Molecules ◽  
2020 ◽  
Vol 25 (16) ◽  
pp. 3616
Author(s):  
Leonardo Bruno Assis Oliveira ◽  
Tertius L. Fonseca ◽  
Benedito J. C. Cabral
Keyword(s):  
Quantum Mechanics ◽  
Statistical Mechanics ◽  
Gas Phase ◽  
Marked Effect ◽  
Complex Structure ◽  
Building Blocks ◽  
15N Nmr ◽  
Magnetic Shielding ◽  
Atomic Orbitals ◽  
Theoretical Results

Theoretical results for the magnetic shielding of protonated and unprotonated nitrogens of eumelanin building blocks including monomers, dimers, and tetramers in gas phase and water are presented. The magnetic property in water was determined by carrying out Monte Carlo statistical mechanics sampling combined with quantum mechanics calculations based on the gauge-including atomic orbitals approach. The results show that the environment polarization can have a marked effect on nitrogen magnetic shieldings, especially for the unprotonated nitrogens. Large contrasts of the oligomerization effect on magnetic shielding show a clear distinction between eumelanin building blocks in solution, which could be detected in nuclear magnetic resonance experiments. Calculations for a π-stacked structure defined by the dimer of a tetrameric building block indicate that unprotonated N atoms are significantly deshielded upon π stacking, whereas protonated N atoms are slightly shielded. The results stress the interest of NMR experiments for a better understanding of the eumelanin complex structure.

Effect of structural variability and flexibility of aliphatic diamines on self-assembly of host-guest coordination polymers constructed of copper cyanide networks: Structure study and catalytic activity

2021 ◽  
Author(s):  
Safaa Eldin H. Etaiw ◽  
Safaa N. Abdou Nabih Abdou
Keyword(s):  
Catalytic Activity ◽  
Self Assembly ◽  
Complex Structure ◽  
Building Blocks ◽  
Structure Study ◽  
Ambient Conditions ◽  
Structural Variability ◽  
3D Network ◽  
Aliphatic Diamines ◽  
Networks Structure

Abstract A new 3D-host-guest supramolecular coordination polymer (SCP); ∞3[(Cu3(CN)3)2.(DAHP)], 1 [1,7-diaminoheptane=.(DAHP)] had been synthesized by self-assembly at ambient conditions. X-ray single crystal diffraction of SCP 1 indicated the formation of two-fold [Cu3(CN)3]2 units containing tetrahedral copper(I) atoms which are arranged in unique way to create 3D-network. The neutral [Cu3(CN)3]2 building blocks create unique complex structure containing the minicycle [Cu2(μ3-CN)2] motif with wide cavities enable to capsulate the long chain DAHP as guest molecule. The topology of 1 had been studied by elemental analysis, IR-spectra and thermogravimetric analyses. The topology of 1 had been compared with the prototype SCP containing different aliphatic diamines which indicated the effect of structural variability and flexibility of aliphatic diamines on the network structure of these SCP. The catalytic and photo-catalytic activity of 1 was studied for mineralization of methylene blue (MB) utilizing H2O2 as an oxidant.

scholarly journals Compositional Inductive Biases in Function Learning

2016 ◽  
Author(s):  
Eric Schulz ◽  
Joshua B. Tenenbaum ◽  
David Duvenaud ◽  
Maarten Speekenbrink ◽  
Samuel J. Gershman
Keyword(s):  
Structure Learning ◽  
Complex Structure ◽  
Building Blocks ◽  
Bayesian Regression ◽  
Learning Approaches ◽  
Function Learning ◽  
Inductive Bias ◽  
Compositional Structure ◽  
Functional Patterns ◽  
Intuitive Theory

AbstractHow do people recognize and learn about complex functional structure? Taking inspiration from other areas of cognitive science, we propose that this is achieved by harnessing compositionality: complex structure is decomposed into simpler building blocks. We formalize this idea within the framework of Bayesian regression using a grammar over Gaussian process kernels, and compare this approach with other structure learning approaches. Participants consistently chose compositional (over non-compositional) extrapolations and interpolations of functions. Experiments designed to elicit priors over functional patterns revealed an inductive bias for compositional structure. Compositional functions were perceived as subjectively more predictable than non-compositional functions, and exhibited other signatures of predictability, such as enhanced memorability and reduced numerosity. Taken together, these results support the view that the human intuitive theory of functions is inherently compositional.

Catalytic chemical processes for biomass conversion: Prospects for future biorefineries

2014 ◽  
Vol 86 (5) ◽  
pp. 843-857 ◽  
Author(s):  
Rafael Luque
Keyword(s):  
Biomass Conversion ◽  
Complex Structure ◽  
Value Added ◽  
Building Blocks ◽  
Chemical Processes ◽  
Relevant Research ◽  
Short Overview ◽  
Platform Chemicals ◽  
Biomass Processing ◽  
Research Avenue

AbstractBiomass is a renewable and abundant feedstock that is poised to become a future alternative to petroleum as the understanding and technology surrounding catalytic biomass conversion and biorefineries progresses. A relevant research avenue explored in recent years deals with biomass deconstruction into simpler compounds (platform chemicals) by overcoming its recalcitrant and complex structure and subsequently converting these building blocks into value-added chemicals, fuels and materials in a similar way to that of current refineries. This contribution is aimed at providing a short overview of biomass processing chemistry by illustrating some relevant examples of catalytic strategies for biorefineries.

Above and beyond the concrete: The diverse representational substrates of the predictive brain

2019 ◽  
Vol 43 ◽  
Author(s):  
Michael Gilead ◽  
Yaacov Trope ◽  
Nira Liberman
Keyword(s):  
Mental Representations ◽  
Complex Structure ◽  
Building Blocks ◽  
Predictive Processing ◽  
Perceptual Similarity ◽  
Abstract Representation ◽  
Trade Off ◽  
Explicit Theory ◽  
The Mind ◽  
Testable Model

Abstract In recent years, scientists have increasingly taken to investigate the predictive nature of cognition. We argue that prediction relies on abstraction, and thus theories of predictive cognition need an explicit theory of abstract representation. We propose such a theory of the abstract representational capacities that allow humans to transcend the “here-and-now.” Consistent with the predictive cognition literature, we suggest that the representational substrates of the mind are built as a hierarchy, ranging from the concrete to the abstract; however, we argue that there are qualitative differences between elements along this hierarchy, generating meaningful, often unacknowledged, diversity. Echoing views from philosophy, we suggest that the representational hierarchy can be parsed into: modality-specific representations, instantiated on perceptual similarity; multimodal representations, instantiated primarily on the discovery of spatiotemporal contiguity; and categorical representations, instantiated primarily on social interaction. These elements serve as the building blocks of complex structures discussed in cognitive psychology (e.g., episodes, scripts) and are the inputs for mental representations that behave like functions, typically discussed in linguistics (i.e., predicators). We support our argument for representational diversity by explaining how the elements in our ontology are all required to account for humans’ predictive cognition (e.g., in subserving logic-based prediction; in optimizing the trade-off between accurate and detailed predictions) and by examining how the neuroscientific evidence coheres with our account. In doing so, we provide a testable model of the neural bases of conceptual cognition and highlight several important implications to research on self-projection, reinforcement learning, and predictive-processing models of psychopathology.

scholarly journals New terpyridine-(β-diketonate)-copper(II) complex. Structure and magnetism

2014 ◽  
Vol 70 (a1) ◽  
pp. C1262-C1262
Author(s):  
Dominique Toledo ◽  
Yanko Moreno ◽  
Octavio Peña ◽  
Ricardo Baggio ◽  
Andrés Vega
Keyword(s):  
Magnetic Measurements ◽  
Complex Structure ◽  
Copper Ion ◽  
Functional Materials ◽  
Building Blocks ◽  
Magnetic Behaviour ◽  
Redox Activity ◽  
Metal Centers ◽  
Design And Synthesis ◽  
Potential Applications

Over the last decade the design and synthesis of metal-organic compounds with fascinating structural properties and potential applications as functional materials has been a major challenge in various fields of research.1Strategies for preparing these compounds are based on the careful selection of the constituent building blocks. 4'-(substituted)-4,2':6',4''-terpyridine ligands are considered versatile building blocks for the assembly of coordination polymers and networks with useful solid-state properties, such as magnetism, luminescence, redox activity, etc.2The divergent arrangements of N-donor atoms and the attachment of aryl substituents into the 4'-position of 4,2':6',4''-terpyridine allow to bridge two or more metal centers, giving rise to molecular assemblies of 1, 2 or 3 dimensions.3Our line of interest is the obtainment of compounds with emergent magnetic properties. Herein we present a copper complex surveying the new 4'-(quinolin-4-yl)-4,2':6',4''-terpyridine ligand (L), and formulated as [Cu(C5H1F6O2)2(C25H16N4·CHCl3)]n which was produced from the reaction of two equivalents of L with Cu(hfac)2, (hfac=hexafluoroacetylacetonate). The copper ion in trans-{CuN2(hfac)2} has an octahedral environment. The nitrogen atoms of the terminal pyridine rings coordinate to the paramagnetic centres, while the central ring remains uncoordinated. The linkage of the resulting polyhedra gives raise to an undulating 1D polymeric structure. Within these chains there are two main non-covalent interactions: π-stacking between the quinoline substituents and the pyridine rings and CH···F interactions due to CF3group of the hfac ligand. There are also weak CH···N, CH···π and π-π intermolecular interactions linking the L and CHCl3groups, which give stability to the crystal structure. Finally, we performed magnetic measurements, in order to determine the magnetic behaviour of our system. Acknowledgments: FONDECYT 1130433 project, CIPA of University of Concepción, LIA-MIF 836

scholarly journals Predictors of Academic Self Efficacy: Intolerance of Uncertainty, Positive Beliefs about Worry and Academic Locus of Control

2020 ◽  
Vol 13 (6) ◽  
pp. 104
Author(s):  
Kıvanç Uzun ◽  
Zeynep Karataş
Keyword(s):  
Locus Of Control ◽  
University Students ◽  
Self Efficacy ◽  
Personal Information ◽  
Complex Structure ◽  
Intolerance Of Uncertainty ◽  
Building Blocks ◽  
Academic Locus Of Control ◽  
The University ◽  
Academic Self Efficacy

Investigation of academic self-efficacy along with intolerance of uncertainty, positive beliefs about worry and academic locus of control is believed to make contributions to the understanding of its complex structure. This study is believed to be of great importance in terms of determining the building blocks to be considered by further research aiming to explain the academic self-efficacy of university students and strengthen their academic self-efficacy. The current study aimed to determine the extent to which the above-mentioned variables predict the academic self-efficacy of university students. The relational survey model was used to reveal the extent to which the above-mentioned variables predict academic self-efficacy. The study was conducted on a total of 717 university students (499 females and 218 males) attending Burdur Mehmet Akif Ersoy University. The data of the current study were collected by using a personal information form developed by the researcher, the academic self-efficacy scale, the intolerance of uncertainty scale, the positive beliefs about worry scale and the academic locus of control scale. In the analysis of the data, Pearson product-moment correlation coefficient and hierarchical multiple regression analysis were used and for this purpose, SPSS 15.0 program was utilized. At the end of the study, it was found that the university students’ academic self-efficacy is positively predicted by positive beliefs about worry and academic internal locus of control and negatively predicted by intolerance of uncertainty and academic external locus of control. The findings of the study were discussed in the light of the related studies previously done by the other researchers.

scholarly journals Supramolecular assembly of protein building blocks: from folding to function

2022 ◽  
Vol 9 (1) ◽  
Author(s):  
Nam Hyeong Kim ◽  
Hojae Choi ◽  
Zafar Muhammad Shahzad ◽  
Heesoo Ki ◽  
Jaekyoung Lee ◽  
...  
Keyword(s):  
Self Assembly ◽  
De Novo ◽  
Complex Structure ◽  
Supramolecular Assembly ◽  
Hierarchical Structures ◽  
Computational Design ◽  
Building Blocks ◽  
Biological Phenomena ◽  
Living Things ◽  
Protein Interfaces

AbstractSeveral phenomena occurring throughout the life of living things start and end with proteins. Various proteins form one complex structure to control detailed reactions. In contrast, one protein forms various structures and implements other biological phenomena depending on the situation. The basic principle that forms these hierarchical structures is protein self-assembly. A single building block is sufficient to create homogeneous structures with complex shapes, such as rings, filaments, or containers. These assemblies are widely used in biology as they enable multivalent binding, ultra-sensitive regulation, and compartmentalization. Moreover, with advances in the computational design of protein folding and protein–protein interfaces, considerable progress has recently been made in the de novo design of protein assemblies. Our review presents a description of the components of supramolecular protein assembly and their application in understanding biological phenomena to therapeutics.

scholarly journals UNIFORMIZATION THEORY AND 2D GRAVITY I: LIOUVILLE ACTION AND INTERSECTION NUMBERS

1995 ◽  
Vol 10 (03) ◽  
pp. 289-335 ◽  
Author(s):  
MARCO MATONE
Keyword(s):  
Riemann Surfaces ◽  
2D Gravity ◽  
Complex Structure ◽  
Virasoro Algebra ◽  
Building Blocks ◽  
Explicit Construction ◽  
Eigenvalues Of The Laplacian ◽  
Higher Genus ◽  
Liouville Action ◽  
Uniformization Theory

This is the first part of an investigation concerning the formulation of 2D gravity in the framework of the uniformization theory of Riemann surfaces. As a first step in this direction we show that the classical Liouville action appears in the expression for the correlators of topological gravity. Next we derive an inequality involving the cutoff of 2D gravity and the background geometry. Another result, still related to uniformization theory, concerns a relation between the higher genus normal ordering and the Liouville action. We introduce operators covariantized by means of the inverse map of uniformization. These operators have interesting properties, including holomorphicity. In particular, they are crucial for showing that the chirally split anomaly of CFT is equivalent to the Krichever-Novikov cocycle and vanishes for deformation of the complex structure induced by the harmonic Beltrami differentials. By means of the inverse map we propose a realization of the Virasoro algebra on arbitrary Riemann surfaces and find the eigenfunctions for the holomorphic covariant operators defining higher order cocycles and anomalies which are related to W algebras. Finally we face the problem of considering the positivity of eσ, with σ the Liouville field, by proposing an explicit construction for the Fourier modes on compact Riemann surfaces. These functions, whose underlying number-theoretic structure seems related to Fuchsian groups and to the eigenvalues of the Laplacian, are quite basic and may provide the building blocks for properly investigating the long-standing uniformization problem posed by Klein, Koebe and Poincaré.

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