scholarly journals Structure and short range order of liquid gallium

2017 ◽  
pp. 7-13
Author(s):  
Roman Bilyk ◽  
Uliana Liudkevych ◽  
Stepan Mudry
Keyword(s):  
Temperature Dependence ◽  
Structure Factor ◽  
Diffraction Method ◽  
Structural Features ◽  
Liquid Gallium ◽  
Heterogeneous Structure ◽  
Structural Factors ◽  
Structural Units ◽  
Different Types ◽  
Structure Of Liquid

The structure of liquid gallium in a wide temperature range has been studied. Analysis of data obtained by diffraction method allowed us to make some conclusions about the structural features of the liquid gallium. In particular there is a clear asymmetry of the first maximum of the structure factor (SF) and existence of shoulder on its right hand side. Also the temperature dependence of structural factors for liquid gallium in terms of its heterogeneous structure was analyzed. Interpretation was carried out under the assumption that the structure of liquid gallium consists of clusters with different distribution of atoms, as well as different types of chemical bonds between atoms. The structural units are sensitive to temperature. Splitting of the structure factor main maximum on the Gaussian partial curves, which corresponded to certain structural units of the melt, was also performed. Each structural component of the melt reveals a different nature of the temperature dependence. It is also assumed that the partial peaks for each cluster are described by Gaussian functions.

Study of the Molecular Architecture of Keratin Filaments by Electron Microscopy

1982 ◽  
Vol 40 ◽  
pp. 118-119
Author(s):  
U. Aebi ◽  
P. Rew ◽  
T.-T. Sun
Keyword(s):  
Electron Microscopy ◽  
Structural Organization ◽  
Cell Types ◽  
Structural Features ◽  
Molecular Architecture ◽  
The Past ◽  
Keratin Filaments ◽  
Different Types ◽  
10 Nm Filaments ◽  
Different Cell Types

Various types of intermediate-sized (10-nm) filaments have been found and described in many different cell types during the past few years. Despite the differences in the chemical composition among the different types of filaments, they all yield common structural features: they are usually up to several microns long and have a diameter of 7 to 10 nm; there is evidence that they are made of several 2 to 3.5 nm wide protofilaments which are helically wound around each other; the secondary structure of the polypeptides constituting the filaments is rich in ∞-helix. However a detailed description of their structural organization is lacking to date.

scholarly journals Controlled growth of ultrafine metal nanoparticles mediated by solid supports

2021 ◽  
Vol 3 (7) ◽  
pp. 1865-1886
Author(s):  
Hongyin Hu ◽  
Shuanglong Lu ◽  
Ting Li ◽  
Yue Zhang ◽  
Chenxi Guo ◽  
...  
Keyword(s):  
Metal Nanoparticles ◽  
Catalytic Properties ◽  
Structural Features ◽  
Controlled Growth ◽  
Solid Supports ◽  
Ultrafine Metal ◽  
Different Types

This article reviews the controlled growth of UMNPs mediated by different types of solid supports and their catalytic properties. The importance of certain structural features of the supports is also discussed.

scholarly journals Evaluating polymer interplay after hot water pretreatment to investigate maize stem internode recalcitrance

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Amandine Leroy ◽  
Xavier Falourd ◽  
Loïc Foucat ◽  
Valérie Méchin ◽  
Fabienne Guillon ◽  
...  
Keyword(s):  
Cell Wall ◽  
Negative Impact ◽  
Lignin Content ◽  
Structural Features ◽  
Hot Water ◽  
Condensed State ◽  
Structural Factors ◽  
Water Pretreatment ◽  
Hot Water Pretreatment ◽  
The Impact

Abstract Background Biomass recalcitrance is governed by various molecular and structural factors but the interplay between these multiscale factors remains unclear. In this study, hot water pretreatment (HWP) was applied to maize stem internodes to highlight the impact of the ultrastructure of the polymers and their interactions on the accessibility and recalcitrance of the lignocellulosic biomass. The impact of HWP was analysed at different scales, from the polymer ultrastructure or water mobility to the cell wall organisation by combining complementary compositional, spectral and NMR analyses. Results HWP increased the kinetics and yield of saccharification. Chemical characterisation showed that HWP altered cell wall composition with a loss of hemicelluloses (up to 45% in the 40-min HWP) and of ferulic acid cross-linking associated with lignin enrichment. The lignin structure was also altered (up to 35% reduction in β–O–4 bonds), associated with slight depolymerisation/repolymerisation depending on the length of treatment. The increase in $${T}_{1\rho }^{H}$$ T 1 ρ H , $${T}_{HH}$$ T HH and specific surface area (SSA) showed that the cellulose environment was looser after pretreatment. These changes were linked to the increased accessibility of more constrained water to the cellulose in the 5–15 nm pore size range. Conclusion The loss of hemicelluloses and changes in polymer structural features caused by HWP led to reorganisation of the lignocellulose matrix. These modifications increased the SSA and redistributed the water thereby increasing the accessibility of cellulases and enhancing hydrolysis. Interestingly, lignin content did not have a negative impact on enzymatic hydrolysis but a higher lignin condensed state appeared to promote saccharification. The environment and organisation of lignin is thus more important than its concentration in explaining cellulose accessibility. Elucidating the interactions between polymers is the key to understanding LB recalcitrance and to identifying the best severity conditions to optimise HWP in sustainable biorefineries.

Radiation Curable Polysiloxane: Synthesis to Applications

Soft Matter ◽  
2021 ◽  
Author(s):  
Selvan T. Muthamil ◽  
Titash Mondal
Keyword(s):  
Structural Features ◽  
Superior Performance ◽  
Operational Conditions ◽  
Different Types

Among the different types of specialty polymers, polysiloxane finds its position in the pyramid's apex in performance attributes. Unique structural features result in superior performance benefits over wide operational conditions....

scholarly journals Cytotoxic Agents in the Minor Alkaloid Groups of the Amaryllidaceae

Planta Medica ◽  
2021 ◽  
Author(s):  
Jerald J. Nair ◽  
Johannes van Staden
Keyword(s):  
Cancer Cells ◽  
Cancer Cell Line ◽  
Structural Features ◽  
Biological Properties ◽  
Cytotoxic Agents ◽  
Plant Family ◽  
Structure Activity ◽  
Significant Interest ◽  
Different Types ◽  
Minor Alkaloid

AbstractOver 600 alkaloids have to date been identified in the plant family Amaryllidaceae. These have been arranged into as many as 15 different groups based on their characteristic structural features. The vast majority of studies on the biological properties of Amaryllidaceae alkaloids have probed their anticancer potential. While most efforts have focused on the major alkaloid groups, the volume and diversity afforded by the minor alkaloid groups have promoted their usefulness as targets for cancer cell line screening purposes. This survey is an in-depth review of such activities described for around 90 representatives from 10 minor alkaloid groups of the Amaryllidaceae. These have been evaluated against over 60 cell lines categorized into 18 different types of cancer. The montanine and cripowellin groups were identified as the most potent, with some in the latter demonstrating low nanomolar level antiproliferative activities. Despite their challenging molecular architectures, the minor alkaloid groups have allowed for facile adjustments to be made to their structures, thereby altering the size, geometry, and electronics of the targets available for structure-activity relationship studies. Nevertheless, it was seen with a regular frequency that the parent alkaloids were better cytotoxic agents than the corresponding semisynthetic derivatives. There has also been significant interest in how the minor alkaloid groups manifest their effects in cancer cells. Among the various targets and pathways in which they were seen to mediate, their ability to induce apoptosis in cancer cells is most appealing.

Acadian strike-slip tectonics in the Gaspé region, Quebec Appalachians

1989 ◽  
Vol 26 (9) ◽  
pp. 1764-1777 ◽  
Author(s):  
Michel Malo ◽  
Jacques Béland
Keyword(s):  
Middle Devonian ◽  
High Strain ◽  
Structural Features ◽  
Fault Zones ◽  
Strike Slip ◽  
Structural Units ◽  
Middle Ordovician ◽  
Southern Margin ◽  
Intense Deformation ◽  
Dextral Strike Slip

At the southern margin of the Cambro-Ordovician Humber Zone in the Quebec Appalachians, on Gaspé Peninsula, three structural units of Middle Ordovician to Middle Devonian cover rocks of the Gaspé Belt are in large part bounded by long, straight longitudinal faults. In one of these units, the Aroostook–Percé anticlinorium, several structural features, which can be ascribed to Acadian deformation, are controlled by three subparallel, dextral, strike-slip longitudinal faults: Grande Rivière, Grand Pabos, and Rivière Garin. These faults follow bands of intense deformation, contrasting with the mildly to moderately deformed intervals that separate them.Most of the structural features observed – rotated oblique folds and cleavage, subsidiary Riedel and tension faults, and offsets of markers – can be integrated in a model of strike-slip tectonics that operated in ductile–brittle conditions. A late increment of deformation in the form of conjugate cleavages and minor faults is restricted to the bands of high strain. An anticlockwise transection of the synfolding cleavage in relation to the oblique hinges may be a feature of the rotational deformation.The combined dextral strike slip that can be measured within the three major longitudinal fault zones amounts to 138 km, to which can be added 17 km of ductile movement in the intervals, for a total of 155 km.

The Hertzian Spectrum of Rubber and Its Micellar Constitution

1946 ◽  
Vol 19 (4) ◽  
pp. 1085-1087
Author(s):  
Pierre Girard ◽  
Paul Abadie
Keyword(s):  
Dielectric Constant ◽  
Electric Field ◽  
Wave Length ◽  
Structural Features ◽  
Loss Angle ◽  
First Case ◽  
Dipolar Molecules ◽  
Alternating Electric Field ◽  
Different Types ◽  
Absorption And Dispersion

Abstract The spectra which were studied lie within the region of hertzian frequencies, and can be represented either by dispersion curves showing the dielectric constant of the substance as a function of the frequency (or wave length λ), or by absorption curves showing the loss angle as a function of this frequency. These two types of curves represent the same phenomenon, i.e., orientation of the dipolar molecules in the alternating electric field, in accordance with the theory of Debye. The spectra and their interpretation depend chiefly on whether the molecules are crystalloid with relatively small and similar dimensions, or are colloidal, with large and unequal dimensions. In the first case, the spectra gives evidence chiefly on the form of the molecules and their structural features. Dilution in a nonpolar solvent shows for certain dipolar compounds, e.g., alcohol, considerable deformations, which differ according to the solvent. In the case of colloids, e.g., rubber, which has a permanent moment, the spectra and the meaning of these spectra are far different. In this case the spectra indicate that the absorption and dispersion values in the hertzian region are closely related to the micellar constitution, i.e., to the different types of micelles, to their size, and to the proportion of each type.

scholarly journals Social Movement Structures in Relation to Goals and Forms of Action: An Exploratory Model

2012 ◽  
Vol 3 (2) ◽  
Author(s):  
Jurgen Willems ◽  
Marc Jegers
Keyword(s):  
Social Movements ◽  
Social Movement ◽  
Classification System ◽  
Structural Features ◽  
Classification Criteria ◽  
Mouvements Sociaux ◽  
Different Types ◽  
Nous Utilisons ◽  
Exploratory Model

ABSTRACT This article describes a theoretical taxonomy of the structural features of social movements. We begin by using two classification criteria to analyze the types of relations that characterize the structure of social movements. From there, we look at how differences in structure relate to different goals and forms of action. We then derive a four-fold classification system based on formalization and hierarchy of relationships. For each classification we provide case descriptions of social movements (or parts thereof) using literature on how different movement structures support different types of goals and forms of action. Furthermore, we discuss the dynamics of social movements (or parts thereof) and how their classification may evolve. By doing so, we illustrate how changes in structure, goals, and forms of action mutually influence each other. RÉSUMÉ Cet article dresse une taxonomie théorique des caractéristiques structurelles des mouvements sociaux. Nous utilisons d’abord deux critères de classification pour analyser les types de relation propres à la structure des mouvements sociaux. Par la suite, nous observons comment des différences de structure coïncident avec des buts et des formes d’action différents. Nous développons ensuite un système de classification quadruple fondé sur la formalisation et l’hiérarchisation des relations. Pour chacune des classifications, nous fournissons des descriptions de cas de mouvements sociaux (ou de parties de ceux-ci) en recourant à des écrits sur la manière dont des structures de mouvement différentes entraînent des buts et des formes d’action différents. En outre, nous discutons des dynamiques des mouvements sociaux (ou de parties de ceux-ci) et comment leur classification pourrait évoluer. Par ce moyen, nous illustrons comment des changements de structure, de but et de forme d’action s’influencent réciproquement.

scholarly journals Macroseismic risk classification of historical constructions: the LEXSIS approach

2021 ◽  
Author(s):  
Irene Puncello ◽  
Silvia Caprili ◽  
Elisa Bonanni
Keyword(s):  
Morphological Evolution ◽  
Structural Features ◽  
Structural Behaviour ◽  
Structural Units ◽  
Knowledge Process ◽  
Risk Ranking ◽  
Hazard Parameters ◽  
Specific Evaluation

AbstractThe present paper deals with the elaboration of a methodology to assess the macro-seismic risk of monumental historical buildings, representing a fundamental part of the European cultural assets. Monumental buildings typically arise from a very complex constructive and morphological evolution process characterised by modifications occurred over the centuries. Therefore, they are usually heterogeneous buildings similar to 'structural aggregates' rather than single constructions and characterised by a structural behaviour depending on the mutual interaction of different structural units. An accurate knowledge process can allow the determination of structural units within the complex: such units can be therefore analysed using a specific evaluation form conceived to provide a 'risk ranking' of the different portions constituting the aggregate and accounting for vulnerability, exposure and seismic hazard parameters. The proposed methodology exploits what is already used to quickly determine structural features and eventual damages in the post-earthquake phase for ordinary buildings, introducing specific aspects typical of historical-cultural heritage requiring attention. According to the results achieved, retrofit interventions or deepen investigations can be planned for units provided by a higher position in the risk scale, optimising and rationally planning the use of available economic and time resources. In the present work, the proposed methodology is applied to the monumental complex of the Certosa di Calci, Pisa (Italy).

scholarly journals Service sector (services) key features of Russia and Azerbaijan

2019 ◽  
Vol 27 (1) ◽  
pp. 18-34
Author(s):  
Mikhail E. Savlov
Keyword(s):  
Service Sector ◽  
Value Added ◽  
Developed Countries ◽  
Structural Features ◽  
Heterogeneous Structure ◽  
General Description ◽  
Material Production ◽  
Brics Countries ◽  
Macroeconomic Indicators ◽  
Per Capita

The presented article gives a general description of the sphere of non-material production of Russia and Azerbaijan, which is based on the key macroeconomic indicators. The internal heterogeneous structure of the sector is also illustrated, structural features of the service sector and its individual segments in both countries are revealed. The objectivity and adequacy of the sphere characteristics of non-material production of Russia and Azerbaijan is based on intercountry comparisons. Macroeconomic indicators of main developed countries (the USA, Japan, Germany, France, the United Kingdom), the BRICS countries and the former Soviet republics serve as a background for the illustration of the service sectors of Russia and Azerbaijan. It is too early to refer Russia and Azerbaijan to post-industrial countries, even considering only one economic parameter - the structure of the economy. Considering the gross value added (GVA) of the service sector per capita in current prices and the GVA of the service sector per capita in constant 2010 prices, Russia and Azerbaijan lag behind the leading economies of the world, some BRICS countries and even some former republics of USSR. In this regard, the study of the sphere of intangible production is not so popular in Russia and Azerbaijan, as the economic background for the actualization of these studies has not been yet created.

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