Volcanoes: Identifying and Evaluating Their Significant Geoheritage Features from the Large to Small Scale

Across the globe, volcanoes and volcanic terrains present one of the most complex geological systems on Earth that, depending on magma type, viscosity, and water and gas content, form a diverse range of products in terms of geomorphology, lithologic suites, structures, and stratigraphy. In broad terms, magmas, with their diagnostic composition, derive from specific tectonic settings, e.g., basalt-dominated oceanic crusts, acidic magma from continental plates, and andesitic convergent-plate margins. In addition to magma composition and volcanic rock types, there is a wide range of volcanic products, manifest at all scales, dependent on how magma interacts with the Earth’s surface, varying, for instance, from lava flows such as vesicular lava beds and flow-banded to flow-laminated lava beds, to breccias, tephra (ejecta) deposits, and bombs, amongst others, each commonly with their diagnostic small-scale lithological/structural features. This wealth of rock types, stratigraphy, and structures linked to geologic setting, potentially has geoheritage significance, and we provide here methods tailored for volcanoes and volcanic rocks of identifying, classifying and evaluating the complex and heterogeneous nature of volcanoes so that the full complement of their geology for a given region can be appreciated and incorporated into thematic geoparks, Nature Reserves and protected areas. For sites of geoheritage significance, we present (1) a globally-applicable Geoheritage Tool-kit to systematically identify volcanic geoheritage sites, (2) a technique to classify/categorise geoheritage sites, and (3) a semi-quantitative method to evaluate the geoheritage significance of volcanic sites.

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Lower Crustal Heterogeneity and Fractional Crystallization Control Evolution of Small-volume Magma Batches at Ocean Island Volcanoes (Ascension Island, South Atlantic)

Journal of Petrology ◽

10.1093/petrology/egz037 ◽

2019 ◽

Vol 60 (8) ◽

pp. 1489-1522 ◽

Cited By ~ 2

Author(s):

K J Chamberlain ◽

J Barclay ◽

K J Preece ◽

R J Brown ◽

J P Davidson

Keyword(s):

Fractional Crystallization ◽

Lower Crust ◽

South Atlantic ◽

Small Scale ◽

Evolutionary Trend ◽

Diverse Range ◽

Ocean Island ◽

Ascension Island ◽

Wide Range

Abstract Ocean island volcanoes erupt a wide range of magmatic compositions via a diverse range of eruptive styles. Understanding where and how these melts evolve is thus an essential component in the anticipation of future volcanic activity. Here we examine the role of crustal structure and magmatic flux in controlling the location, evolution and ultimately composition of melts at Ascension Island. Located in the South Atlantic, Ascension Island is an ocean island volcano that has produced a continuum of eruptive compositions from basalt to rhyolite in its 1 Myr subaerial eruptive history. Volcanic rocks broadly follow a silica-undersaturated subalkaline evolutionary trend, and new data presented here show a continuous compositional trend from basalt through trachyte to rhyolite. Detailed petrographic observations are combined with in situ geochemical analyses of crystals and glass, and new whole-rock major and trace element data from mafic and felsic pyroclastic and effusive deposits that span the entire range in eruptive ages and compositions found on Ascension Island. These data show that extensive fractional crystallization is the main driver for the production of felsic melts for Ascension Island, a volcano built on thin, young, oceanic crust. Strong spatial variations in the compositions of erupted magmas reveal the role of a heterogeneous lower crust; differing degrees of interaction with a zone of plutonic rocks are responsible for the range in mafic lava compositions, and for the formation of the central and eastern felsic complexes. A central core of nested, small-scale plutonic, or mush-like, bodies inhibits the ascent of mafic magmas, allowing sequential fractional crystallization within the lower crust, and generating felsic magmas in the core of the island. There is no evidence for magma mixing preserved in any of the studied eruptions, suggesting that magma storage regions are transient, and material is not recycled between eruptions.

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Acetylation of Surface Carbohydrates in Bacterial Pathogens Requires Coordinated Action of a Two-Domain Membrane-Bound Acyltransferase

mBio ◽

10.1128/mbio.01364-20 ◽

2020 ◽

Vol 11 (4) ◽

Author(s):

Caroline R. Pearson ◽

Sarah N. Tindall ◽

Reyme Herman ◽

Huw T. Jenkins ◽

Alex Bateman ◽

...

Keyword(s):

Membrane Proteins ◽

Mechanism Of Action ◽

Domain Architecture ◽

Structural Features ◽

Acyl Donor ◽

Diverse Range ◽

Wide Range ◽

Membrane Bound ◽

Surface Carbohydrates

ABSTRACT Membrane bound acyltransferase-3 (AT3) domain-containing proteins are implicated in a wide range of carbohydrate O-acyl modifications, but their mechanism of action is largely unknown. O-antigen acetylation by AT3 domain-containing acetyltransferases of Salmonella spp. can generate a specific immune response upon infection and can influence bacteriophage interactions. This study integrates in situ and in vitro functional analyses of two of these proteins, OafA and OafB (formerly F2GtrC), which display an “AT3-SGNH fused” domain architecture, where an integral membrane AT3 domain is fused to an extracytoplasmic SGNH domain. An in silico-inspired mutagenesis approach of the AT3 domain identified seven residues which are fundamental for the mechanism of action of OafA, with a particularly conserved motif in TMH1 indicating a potential acyl donor interaction site. Genetic and in vitro evidence demonstrate that the SGNH domain is both necessary and sufficient for lipopolysaccharide acetylation. The structure of the periplasmic SGNH domain of OafB identified features not previously reported for SGNH proteins. In particular, the periplasmic portion of the interdomain linking region is structured. Significantly, this region constrains acceptor substrate specificity, apparently by limiting access to the active site. Coevolution analysis of the two domains suggests possible interdomain interactions. Combining these data, we propose a refined model of the AT3-SGNH proteins, with structurally constrained orientations of the two domains. These findings enhance our understanding of how cells can transfer acyl groups from the cytoplasm to specific extracellular carbohydrates. IMPORTANCE Acyltransferase-3 (AT3) domain-containing membrane proteins are involved in O-acetylation of a diverse range of carbohydrates across all domains of life. In bacteria they are essential in processes including symbiosis, resistance to antimicrobials, and biosynthesis of antibiotics. Their mechanism of action, however, is poorly characterized. We analyzed two acetyltransferases as models for this important family of membrane proteins, which modify carbohydrates on the surface of the pathogen Salmonella enterica, affecting immunogenicity, virulence, and bacteriophage resistance. We show that when these AT3 domains are fused to a periplasmic partner domain, both domains are required for substrate acetylation. The data show conserved elements in the AT3 domain and unique structural features of the periplasmic domain. Our data provide a working model to probe the mechanism and function of the diverse and important members of the widespread AT3 protein family, which are required for biologically significant modifications of cell-surface carbohydrates.

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Nine Centuries of Man

10.3366/edinburgh/9781474403894.001.0001 ◽

2017 ◽

Cited By ~ 5

Keyword(s):

Twentieth Century ◽

Diverse Range ◽

Gender Expectations ◽

Court Records ◽

The Past ◽

Wide Range ◽

Police Reports ◽

Late Twentieth ◽

Scottish History ◽

Late Twentieth Century

What did it mean to be a man in Scotland over the past nine centuries? Scotland, with its stereotypes of the kilted warrior and the industrial ‘hard man’, has long been characterised in masculine terms, but there has been little historical exploration of masculinity in a wider context. This interdisciplinary collection examines a diverse range of the multiple and changing forms of masculinities from the late eleventh to the late twentieth century, exploring the ways in which Scottish society through the ages defined expectations for men and their behaviour. How men reacted to those expectations is examined through sources such as documentary materials, medieval seals, romances, poetry, begging letters, police reports and court records, charity records, oral histories and personal correspondence. Focusing upon the wide range of activities and roles undertaken by men – work, fatherhood and play, violence and war, sex and commerce – the book also illustrates the range of masculinities that affected or were internalised by men. Together, the chapters illustrate some of the ways Scotland’s gender expectations have changed over the centuries and how, more generally, masculinities have informed the path of Scottish history

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Diversity and Integration in Private International Law

10.3366/edinburgh/9781474447850.001.0001 ◽

2019 ◽

Keyword(s):

South America ◽

International Law ◽

Value Systems ◽

Private International Law ◽

Diverse Range ◽

Cross Border ◽

Wide Range ◽

Depth Analysis ◽

And Shifts ◽

Substantive Law

This book opens a cross-regional dialogue and shifts the Eurocentric discussion on diversity and integration to a more inclusive engagement with South America in private international law issues. It promotes a contemporary vision of private international law as a discipline enabling legal interconnectivity, with the potential to transcend its disciplinary boundaries to further promote the reality of cross-border integration, with its focus on the ever-increasing cross-border mobility of individuals. Private international law embraces legal diversity and pluralism. Different legal traditions continue to meet, interact and integrate in different forms, at the national, regional and international levels. Different systems of substantive law couple with divergent systems of private international law (designed to accommodate the former in cross-border situations). This complex legal landscape impacts individuals and families in cross-border scenarios, and international commerce broadly conceived. Private international law methodologies and techniques offer means for the coordination of this constellation of legal orders and value systems in cross-border situations. Bringing together world-renowned academics and experienced private international lawyers from a wide range of jurisdictions in Europe and South America, this edited collection focuses on the connective capabilities of private international law in bridging and balancing legal diversity as a corollary for the development of integration. The book provides in-depth analysis of the role of private international law in dealing with legal diversity across a diverse range of topics and jurisdictions.

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pH-Dependent Thermal Stability of Vibrio cholerae L-asparaginase

Protein and Peptide Letters ◽

10.2174/0929866526666190617092944 ◽

2019 ◽

Vol 26 (10) ◽

pp. 743-750 ◽

Cited By ~ 1

Author(s):

Remya Radha ◽

Sathyanarayana N. Gummadi

Keyword(s):

Vibrio Cholerae ◽

Conformational Changes ◽

Kinetic Studies ◽

Structural Features ◽

Structure Stability ◽

Kcal Mole ◽

Scanning Calorimetry ◽

Wide Range ◽

Ph Dependent ◽

Ph Range

Background:pH is one of the decisive macromolecular properties of proteins that significantly affects enzyme structure, stability and reaction rate. Change in pH may protonate or deprotonate the side group of aminoacid residues in the protein, thereby resulting in changes in chemical and structural features. Hence studies on the kinetics of enzyme deactivation by pH are important for assessing the bio-functionality of industrial enzymes. L-asparaginase is one such important enzyme that has potent applications in cancer therapy and food industry.Objective:The objective of the study is to understand and analyze the influence of pH on deactivation and stability of Vibrio cholerae L-asparaginase.Methods:Kinetic studies were conducted to analyze the effect of pH on stability and deactivation of Vibrio cholerae L-asparaginase. Circular Dichroism (CD) and Differential Scanning Calorimetry (DSC) studies have been carried out to understand the pH-dependent conformational changes in the secondary structure of V. cholerae L-asparaginase.Results:The enzyme was found to be least stable at extreme acidic conditions (pH< 4.5) and exhibited a gradual increase in melting temperature from 40 to 81 °C within pH range of 4.0 to 7.0. Thermodynamic properties of protein were estimated and at pH 7.0 the protein exhibited ΔG37of 26.31 kcal mole-1, ΔH of 204.27 kcal mole-1 and ΔS of 574.06 cal mole-1 K-1.Conclusion:The stability and thermodynamic analysis revealed that V. cholerae L-asparaginase was highly stable over a wide range of pH, with the highest stability in the pH range of 5.0–7.0.

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Application of Nitrogen Heterocyclic Carbenes in Organocatalysis

Current Catalysis ◽

10.2174/2211544709999201201120617 ◽

2020 ◽

Vol 09 ◽

Author(s):

Minita Ojha ◽

R. K. Bansal

Keyword(s):

Asymmetric Catalysis ◽

Building Blocks ◽

Structural Features ◽

Heterocyclic Carbenes ◽

Stetter Reaction ◽

Metal Pollutants ◽

Synthetic Strategy ◽

Wide Range ◽

Benzoin Condensation ◽

Nitrogen Heterocyclic

Background: During the last two decades, horizon of research in the field of Nitrogen Heterocyclic Carbenes (NHC) has widened remarkably. NHCs have emerged as ubiquitous species having applications in a broad range of fields, including organocatalysis and organometallic chemistry. The NHC-induced non-asymmetric catalysis has turned out to be a really fruitful area of research in recent years. Methods: By manipulating structural features and selecting appropriate substituent groups, it has been possible to control the kinetic and thermodynamic stability of a wide range of NHCs, which can be tolerant to a variety of functional groups and can be used under mild conditions. NHCs are produced by different methods, such as deprotonation of Nalkylhetrocyclic salt, transmetallation, decarboxylation and electrochemical reduction. Results: The NHCs have been used successfully as catalysts for a wide range of reactions making a large number of building blocks and other useful compounds accessible. Some of these reactions are: benzoin condensation, Stetter reaction, Michael reaction, esterification, activation of esters, activation of isocyanides, polymerization, different cycloaddition reactions, isomerization, etc. The present review includes all these examples published during the last 10 years, i.e. from 2010 till date. Conclusion: The NHCs have emerged as versatile and powerful organocatalysts in synthetic organic chemistry. They provide the synthetic strategy which does not burden the environment with metal pollutants and thus fit in the Green Chemistry.

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Cultural Accommodation of Internet-Based Interventions for Substance Use and Related Disorders: A Proposed Comprehensive Framework (Preprint)

10.2196/preprints.16328 ◽

2019 ◽

Author(s):

Keren Gueta ◽

Yossi Harel-Fisch ◽

Sophie D. Walsh

Keyword(s):

Substance Use ◽

Ecological Validity ◽

Limited Attention ◽

Diverse Range ◽

Four Dimensions ◽

Service Engagement ◽

Wide Range ◽

Cultural Accommodation ◽

Abuse Treatment ◽

Comprehensive Framework

BACKGROUND Despite the low utilization rates of substance use and related disorders services, and the ability of internet-based interventions for substance use and related disorders (IBIS) to address challenges related to service engagement, limited attention has been placed on the processes for the accommodation of these interventions to diverse cultural settings. OBJECTIVE The purpose of this study was to develop a conceptual framework for the cultural accommodation of IBIS across populations, settings, and countries. METHODS A pilot study of cultural accommodation of an existing internet intervention for alcohol use (Down Your Drink (DYD)), focus groups and daily online surveys of prospective consumers (N=24) and interviews with experts (N=7) in the substance abuse treatment field were conducted. RESULTS Thematic analysis revealed a wide range of themes identified as needing to be addressed in the process of DYD accommodation. It also emphasized that accommodation needs to incorporate both technical and contents themes, shaped by both the general Israeli cultural as well as by the specific Israeli drinking subculture. A combined mixed emic–etic theoretical approach incorporating the pilot findings together with a scoping literature review was employed to develop a framework for cultural accommodation of IBIS. A comprehensive framework for cultural accommodation of IBIS is introduced consisting of five chronological stages of IBIS accommodation and four dimensions of accommodation. CONCLUSIONS The proposed framework can serve as a guide for the cultural accommodation of existing IBIS across a diverse range of cultural and geographical settings thus augmenting the ecological validity of IBIS and reducing health disparities worldwide.

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Integrated Design and Multi-Objective Optimization of a Single Stage Heat-Pump Turbocompressor

Volume 3B: 39th Design Automation Conference ◽

10.1115/detc2013-12180 ◽

2013 ◽

Author(s):

J. Schiffmann

Keyword(s):

Design Optimization ◽

High Efficiency ◽

Integrated Design ◽

Heat Pumps ◽

Small Scale ◽

Multi Objective Optimization ◽

Design Constraints ◽

Multi Objective ◽

Wide Range ◽

Standard Design

Small scale turbomachines in domestic heat pumps reach high efficiency and provide oil-free solutions which improve heat-exchanger performance and offer major advantages in the design of advanced thermodynamic cycles. An appropriate turbocompressor for domestic air based heat pumps requires the ability to operate on a wide range of inlet pressure, pressure ratios and mass flows, confronting the designer with the necessity to compromise between range and efficiency. Further the design of small-scale direct driven turbomachines is a complex and interdisciplinary task. Textbook design procedures propose to split such systems into subcomponents and to design and optimize each element individually. This common procedure, however, tends to neglect the interactions between the different components leading to suboptimal solutions. The authors propose an approach based on the integrated philosophy for designing and optimizing gas bearing supported, direct driven turbocompressors for applications with challenging requirements with regards to operation range and efficiency. Using previously validated reduced order models for the different components an integrated model of the compressor is implemented and the optimum system found via multi-objective optimization. It is shown that compared to standard design procedure the integrated approach yields an increase of the seasonal compressor efficiency of more than 12 points. Further a design optimization based sensitivity analysis allows to investigate the influence of design constraints determined prior to optimization such as impeller surface roughness, rotor material and impeller force. A relaxation of these constrains yields additional room for improvement. Reduced impeller force improves efficiency due to a smaller thrust bearing mainly, whereas a lighter rotor material improves rotordynamic performance. A hydraulically smoother impeller surface improves the overall efficiency considerably by reducing aerodynamic losses. A combination of the relaxation of the 3 design constraints yields an additional improvement of 6 points compared to the original optimization process. The integrated design and optimization procedure implemented in the case of a complex design problem thus clearly shows its advantages compared to traditional design methods by allowing a truly exhaustive search for optimum solutions throughout the complete design space. It can be used for both design optimization and for design analysis.

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A Slot-Die Technique for the Preparation of Continuous, High-Area, Chitosan-Based Thin Films

Polymers ◽

10.3390/polym13101566 ◽

2021 ◽

Vol 13 (10) ◽

pp. 1566

Author(s):

Oliver J. Pemble ◽

Maria Bardosova ◽

Ian M. Povey ◽

Martyn E. Pemble

Keyword(s):

Thin Films ◽

Mechanical Properties ◽

High Volume ◽

Mechanical Anisotropy ◽

Diverse Range ◽

Direction Parallel ◽

High Area ◽

Wide Range ◽

Slot Die ◽

Potential Applications

Chitosan-based films have a diverse range of potential applications but are currently limited in terms of commercial use due to a lack of methods specifically designed to produce thin films in high volumes. To address this limitation directly, hydrogels prepared from chitosan, chitosan-tetraethoxy silane, also known as tetraethyl orthosilicate (TEOS) and chitosan-glutaraldehyde have been used to prepare continuous thin films using a slot-die technique which is described in detail. By way of preliminary analysis of the resulting films for comparison purposes with films made by other methods, the mechanical strength of the films produced was assessed. It was found that as expected, the hybrid films made with TEOS and glutaraldehyde both show a higher yield strength than the films made with chitosan alone. In all cases, the mechanical properties of the films were found to compare very favorably with similar measurements reported in the literature. In order to assess the possible influence of the direction in which the hydrogel passes through the slot-die on the mechanical properties of the films, testing was performed on plain chitosan samples cut in a direction parallel to the direction of travel and perpendicular to this direction. It was found that there was no evidence of any mechanical anisotropy induced by the slot die process. The examples presented here serve to illustrate how the slot-die approach may be used to create high-volume, high-area chitosan-based films cheaply and rapidly. It is suggested that an approach of the type described here may facilitate the use of chitosan-based films for a wide range of important applications.

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Ring-Forming Polymerization toward Perfluorocyclobutyl and Ortho-Diynylarene-Derived Materials: From Synthesis to Practical Applications

Materials ◽

10.3390/ma14061486 ◽

2021 ◽

Vol 14 (6) ◽

pp. 1486

Author(s):

Eugene B. Caldona ◽

Ernesto I. Borrego ◽

Ketki E. Shelar ◽

Karl M. Mukeba ◽

Dennis W. Smith

Keyword(s):

Chemical Resistance ◽

Structural Features ◽

Review Article ◽

Aryl Ether ◽

Aromatic Rings ◽

Practical Applications ◽

Repeat Units ◽

Wide Range ◽

Synthetic Routes ◽

The Cost

Many desirable characteristics of polymers arise from the method of polymerization and structural features of their repeat units, which typically are responsible for the polymer’s performance at the cost of processability. While linear alternatives are popular, polymers composed of cyclic repeat units across their backbones have generally been shown to exhibit higher optical transparency, lower water absorption, and higher glass transition temperatures. These specifically include polymers built with either substituted alicyclic structures or aromatic rings, or both. In this review article, we highlight two useful ring-forming polymer groups, perfluorocyclobutyl (PFCB) aryl ether polymers and ortho-diynylarene- (ODA) based thermosets, both demonstrating outstanding thermal stability, chemical resistance, mechanical integrity, and improved processability. Different synthetic routes (with emphasis on ring-forming polymerization) and properties for these polymers are discussed, followed by their relevant applications in a wide range of aspects.

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