scholarly journals Gelation or molecular recognition; is the bis-(α,β-dihydroxy ester)s motif an omnigelator?

2010 ◽  
Vol 6 ◽  
pp. 1079-1088 ◽  
Author(s):  
Peter C Griffiths ◽  
David W Knight ◽  
Ian R Morgan ◽  
Amy Ford ◽  
James Brown ◽  
...  
Keyword(s):  
Molecular Recognition ◽  
Neutron Scattering ◽  
Spin Echo ◽  
Inelastic Neutron ◽  
Gelation Mechanism ◽  
Regular Structures ◽  
Low Concentrations ◽  
Wide Range ◽  
History Of ◽  
Selection Of

Understanding the gelation of liquids by low molecular weight solutes at low concentrations gives an insight into many molecular recognition phenomena and also offers a simple route to modifying the physical properties of the liquid. Bis-(α,β-dihydroxy ester)s are shown here to gel thermoreversibly a wide range of solvents, raising interesting questions as to the mechanism of gelation. At gelator concentrations of 5–50 mg ml−1, gels were successfully formed in acetone, ethanol/water mixtures, toluene, cyclohexane and chloroform (the latter, albeit at a higher gelator concentration). A range of neutron techniques – in particular small-angle neutron scattering (SANS) – have been employed to probe the structure of a selection of these gels. The universality of gelation in a range of solvent types suggests the gelation mechanism is a feature of the bis-(α,β-dihydroxy ester) motif, with SANS demonstrating the presence of regular structures in the 30–40 Å range. A correlation between the apparent rodlike character of the structures formed and the polarity of the solvent is evident. Preliminary spin-echo neutron scattering studies (SESANS) indicated the absence of any larger scale structures. Inelastic neutron spectroscopy (INS) studies demonstrated that the solvent is largely unaffected by gelation, but does reveal insights into the thermal history of the samples. Further neutron studies of this kind (particularly SESANS and INS) are warranted, and it is hoped that this work will stimulate others to pursue this line of research.

Le fonti, i metodi e le narrazioni della storia della videoarte in Italia negli anni Settanta

2017 ◽  
Vol 2 (1) ◽  
Author(s):  
Lisa Parola
Keyword(s):  
Comparative Study ◽  
Contemporary Art ◽  
Narrative Structure ◽  
Video Art ◽  
Wide Range ◽  
History Of ◽  
Selection For ◽  
The Many ◽  
Art And Architecture ◽  
Selection Of

This essay derives from the primary need to make order between direct and indirect sources available for the reconstruction of the history of video art in Italy in the seventies. In fact, during the researches for the Ph.D. thesis it became clear that in most cases it is difficult to define, in terms of facts, which of the different historiographies should be taken into consideration to deepen the study of video art in Italy. Beyond legitimate differences of perspectives and methods, historiographical narratives all share similar issues and narrative structure. The first intention of the essay is, therefore, to compare the different historiographic narratives on Italian video art of the seventies, verifying their genealogy, the sources used and the accuracy of the narrated facts. For the selection of the corpus, it was decided to analyze in particular monographic volumes dealing with the history of the origins of video art in Italy. The aim was, in fact, to get a wide range of types of "narrations", as in the case of contemporary art and architecture magazines, which are examined in the second part of the essay. After the selection, for an analytical and comparative study of the various historiography, the essay focuses only on the Terza Biennale Internazionale della Giovane Pittura. Gennaio ’70. Comportamenti, oggetti e mediazioni (Third International Biennial of Young Painting. January '70. Behaviors, Objects and Mediations, 1970, Bologna), the exhibition which - after Lucio Fontana's pioneering experiments - is said to be the first sign of the arrival of videotape in Italy (called at the time videorecording), curated by Renato Barilli, Tommaso Trini, Andrea Emiliani and Maurizio Calvesi. The narration given so far of this exhibition appeared more mythological than historical and could be compared structurally to that of the many numerous beginnings that historiographyies on international video art identify as ‘first’ and ‘generative’. In the first part of the essay the 'facts' related to Gennaio ’70, as narrated by historiography on video art, are compared. In the second part the survey is carried out through some of the direct sources identified during the research, with the aim of answering to questions raised by the comparison between historiographies. Concluding, it is important to underline that the tapes containing the videos transmitted have not been found and seem to have disappeared since the ending of the exhibition. Nevertheless, the deepening of the works and documentation transmitted during the exhibition is possible thanks to other types of sources which give us many valuable information regarding video techniques and practices at the beginning of 1970 in Italy.

Short Fictions of Improvement by James Hogg and Walter Scott

2020 ◽  
pp. 72-111
Author(s):  
Gerard Lee McKeever
Keyword(s):  
Short Fiction ◽  
Formal Logic ◽  
Literary Marketplace ◽  
James Hogg ◽  
Wide Range ◽  
Revisionist History ◽  
History Of ◽  
Walter Scott ◽  
Selection Of ◽  
Half Decade

This chapter reads James Hogg and Walter Scott within a new, revisionist history of short fiction that is particularly interested in the genre of the ‘tale’. Focusing on the half-decade between 1827 and 1831, the chapter highlights a selection of Hogg’s mature contributions to Blackwood’s Edinburgh Magazine alongside Scott’s Chronicles of the Canongate (first series). These years were marked by literary experimentation, when a confident improving persuasion in Scottish culture was threatening to unravel. The formal logic of these short fictions, defined by a curiously focused spontaneity, exacerbates a pluralistic handling of the collision between improvement and tradition. Different models of time (progress, renewal, disruption) and belief (suspension, scepticism, credulity) serve to interrogate improvement in a wide range of contexts around commercial modernisation. The chapter unpacks two specific literary innovations in this context. The first looks to acts of transmission in the literary marketplace which by turns sustain, contain and defer the dialectics of improvement. The second sees the emergence of a fully fledged aesthetic vocabulary of culture in Scott’s writing.

Anger Management Training in Prison Inmates

1997 ◽  
Vol 81 (2) ◽  
pp. 623-626 ◽  
Author(s):  
Mark I. Holbrook
Keyword(s):  
Anger Management ◽  
Reactive Aggression ◽  
Management Training ◽  
Antisocial Behaviors ◽  
Instrumental Aggression ◽  
Wide Range ◽  
History Of ◽  
Male Inmates ◽  
Behavioral Methods ◽  
Selection Of

Inflicting harm on others after a perceived wrong is called revenge and has been implicated in a wide range of criminal and antisocial behaviors. Revenge is defined as a retaliatory act and may be ruled out when antecedent to instrumental aggression if hurting someone is secondary to the primary goal of acquisition. Revenge is considered the Impetus for reactive aggression, however, if the primary goal is to hurt someone. 26 male inmates were chosen for training in anger management using cognitive behavioral methods. Selection of inmates was based on their history of reactive aggression. As predicted, inmates showed a significant reduction in posttest scores on the Vengeance scale.

Western Asia

2020 ◽  
pp. 513-539
Author(s):  
Carolyn Routledge
Keyword(s):  
Case Studies ◽  
Ancient Egypt ◽  
The State ◽  
Academic Disciplines ◽  
Theoretical Approaches ◽  
Western Asia ◽  
Wide Range ◽  
History Of ◽  
Selection Of

Since Flinders Petrie, the importance of Western Asia to the history and development of culture in ancient Egypt has been recognized by scholars and has also been a significant driver in shaping Egyptological methodology and theoretical approaches. The study of relations between Western Asia and Egypt encompasses a wide range of specialisms given the broad range of evidence, the geographical breadth, and the academic disciplines involved. This chapter reviews the history of the study of relations between Western Asia and Egypt pointing to a selection of challenges scholars face in undertaking their research, and examines two case studies: theories concerning the role of Western Asia in the rise of the state, and the assessment of Egypt’s New Kingdom Empire in Canaan to illustrate the ways in which scholarly challenges are met and the resulting historical conclusions.

scholarly journals Investigations of Hydrocarbon Species on Solid Catalysts by Inelastic Neutron Scattering

2020 ◽  
Author(s):  
Longfei Lin ◽  
Qingqing Mei ◽  
Xue Han ◽  
Stewart F. Parker ◽  
Sihai Yang
Keyword(s):  
Heterogeneous Catalysis ◽  
Neutron Scattering ◽  
Vibrational Spectroscopy ◽  
Inelastic Neutron Scattering ◽  
Inelastic Neutron ◽  
Surface Species ◽  
Catalytic Systems ◽  
Selection Rules ◽  
Solid Catalysts ◽  
Wide Range

Abstract The status of surface species on solid catalysts during heterogeneous catalysis is often mysterious. Investigations of these surface species are crucial to deconvolute the reaction network and design more efficient catalysts. Vibrational spectroscopy is a powerful technique to study the interactions between surface species and the catalysts and infrared (IR) and Raman spectroscopies have been widely applied to study reaction mechanisms in heterogeneous catalysis. However, IR/Raman spectra are difficult to model computationally and important vibrational modes may be IR-, Raman- (or both) inactive due to restrictions by optical selection rules. Inelastic neutron scattering (INS) is another form of vibrational spectroscopy and relies on the scattering of neutrons by the atomic nucleus. A consequence of this is that INS is not subject to any optical selection rules and all vibrations are measurable in principle. INS spectroscopy has been used to investigate surface species on catalysts in a wide range of heterogeneous catalytic reactions. In this mini-review, we focus on applications of INS in two important fields: petrochemical reactions and C1 chemistry. We introduce the basic principles of the INS technique, followed by a discussion of its application in investigating two key catalytic systems: (i) the behaviour of hydrocarbons on metal-oxide and zeolite catalysts and (ii) the formation of hydrocarbonaceous species on methane reforming and Fischer–Tropsch catalysts. The power of INS in studying these important catalytic systems is demonstrated.

The Limits of Free Will

2017 ◽  
Author(s):  
Paul Russell
Keyword(s):  
Moral Responsibility ◽  
Free Will ◽  
Moral Psychology ◽  
Practical Reason ◽  
The Past ◽  
Wide Range ◽  
History Of ◽  
The Subject ◽  
Moral Capacity ◽  
Selection Of

This volume contains a selection of chapters concerning free will and moral responsibility. The problems arising in this field of philosophy, which are deeply rooted in the history of the subject, are also intimately related to a wide range of other fields, such as law and criminology, moral psychology, theology, and, more recently, neuroscience. The chapters included in this collection were written and first published over a period of three decades, although most have appeared in the past decade or so. During this period this area of philosophy has been particularly active and it continues to attract a great deal of interest and attention. Among the topics covered, as they relate to these problems, are the challenge of skepticism; moral sentiment and moral capacity; necessity and the metaphysics of causation; practical reason; free will and art; fatalism and the limits of agency; and our metaphysical attitudes of optimism and pessimism.

Which glue to choose? A neutron scattering study of various adhesive materials and their effect on background scattering

2018 ◽  
Vol 51 (6) ◽  
pp. 1766-1772 ◽  
Author(s):  
Kirrily C. Rule ◽  
Richard A. Mole ◽  
Dehong Yu
Keyword(s):  
Neutron Scattering ◽  
Cold Neutron ◽  
Inelastic Neutron Scattering ◽  
Inelastic Neutron ◽  
Background Signal ◽  
Wide Range ◽  
Neutron Time ◽  
Scattering Study ◽  
Neutron Scattering Study ◽  
Adhesive Materials

The background scattering from numerous frequently used sample adhesives has been investigated to determine the background contribution of these glues when used for inelastic neutron scattering measurements. Starting with a bare Cu sheet, different glues have been trialled, such as GE varnish, CYTOP solution, Teflon tape, Fomblin oil and two-component epoxy glue. Measurements were collected using the PELICAN cold-neutron time-of-flight spectrometer at ANSTO, which is capable of collecting data over a wide range of Q–ω space simultaneously. The results indicate that those glues containing hydrogen give much higher background signals, while those that do not contain hydrogen have a much smaller impact on the background signal. This was observed for both elastic and inelastic neutron scattering.

The use of chromium oxide to estimate the faecal output of Merinos

1963 ◽  
Vol 14 (2) ◽  
pp. 239 ◽  
Author(s):  
LJ Lambourne ◽  
TF Reardon
Keyword(s):  
Chromium Oxide ◽  
Grab Sampling ◽  
Low Concentrations ◽  
Wide Range ◽  
Main Series ◽  
Series Of Experiments ◽  
The Mean ◽  
High Concentrations ◽  
Fixed Times ◽  
Selection Of

The pattern of chromium oxide (Cr2O3) excretion was studied in Merino wethers. The sheep were dosed twice daily with Cr2O3 at fixed times. In the main series of experiments, sheep were fed fresh herbage in metabolism pens. An oaten chaff diet was also employed. In all cases a diurnal pattern of Cr2O3 excretion in the faeces was observed. The pattern was not consistent from day to day, nor was there any consistent effect of level of intake or feeding frequency on the excretion pattern. Distributions of Cr2O3 were examined in eight grazing sheep killed ½–4 hr after dosing. In six of the animals high concentrations of the marker were found to be mixed with the reticuloruminal ingesta, while low concentrations were observed in the other stomachs. In the remaining two animals high concentrations were observed in the omasum and abomasum, from which it was inferred that the dose had by-passed the main bulk of the reticulorurninal ingesia. It seems unlikely that any real advantage is to be gained by painstaking selection of particular times for dosing and faeces sampling in different environments; and it is suggested that convenient fixed times — say 6 a.m. and 3 p.m., or 9 a.m. and 5 p.m. — should prove satisfactory in estimating output of faeces of grazing animals under a wide range of conditions. In 40 sheep-periods of 10–14 days, the mean daily output of faeces organic matter by pen-fed wethers was estimated with mean 101% and error ±12% of the true figures, by analysis of a single bulked sample obtained by dosing and grab sampling at about 9 a.m. and 5 p.m. daily. In 40 periods when samples were bulked over 5–7 days the average estimate was 102 ± 14% of the true figure. Comparison under extensive grazing conditions showed that estimates obtained by dosing and sampling only once per day were generally some 15% higher than those obtained by dosing and sampling twice daily.

scholarly journals Local Effects of Ring Topology Observed in Polymer Conformation and Dynamics by Neutron Scattering—A Review

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1884
Author(s):  
Valeria Arrighi ◽  
Julia S. Higgins
Keyword(s):  
Neutron Scattering ◽  
Molecular Conformation ◽  
Spin Echo ◽  
Neutron Spin ◽  
Cyclic Polymers ◽  
Elastic Neutron ◽  
Molecular Weights ◽  
Dimethyl Siloxane ◽  
Area Of Interest ◽  
Wide Range

The physical properties of polymers depend on a range of both structural and chemical parameters, and in particular, on molecular topology. Apparently simple changes such as joining chains at a point to form stars or simply joining the two ends to form a ring can profoundly alter molecular conformation and dynamics, and hence properties. Cyclic polymers, as they do not have free ends, represent the simplest model system where reptation is completely suppressed. As a consequence, there exists a considerable literature and several reviews focused on high molecular weight cyclics where long range dynamics described by the reptation model comes into play. However, this is only one area of interest. Consideration of the conformation and dynamics of rings and chains, and of their mixtures, over molecular weights ranging from tens of repeat units up to and beyond the onset of entanglements and in both solution and melts has provided a rich literature for theory and simulation. Experimental work, particularly neutron scattering, has been limited by the difficulty of synthesizing well-characterized ring samples, and deuterated analogues. Here in the context of the broader literature we review investigations of local conformation and dynamics of linear and cyclic polymers, concentrating on poly(dimethyl siloxane) (PDMS) and covering a wide range of generally less high molar masses. Experimental data from small angle neutron scattering (SANS) and quasi-elastic neutron scattering (QENS), including Neutron Spin Echo (NSE), are compared to theory and computational predictions.

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