scholarly journals Hierarchically Ordered α-Zirconium Phosphate Platelets in Aqueous Phase with Empty Liquid

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Xi Lin ◽  
Dirk Schmelter ◽  
Sadaf Imanian ◽  
Horst Hintze-Bruening
Keyword(s):  
Zirconium Phosphate ◽  
Liquid Crystalline ◽  
Polymer Particles ◽  
Repeat Distance ◽  
Aqueous Dispersions ◽  
Liquid Crystalline Phases ◽  
Ultra Filtration ◽  
Anisotropic Fluids ◽  
Shed Light

Abstract Platelets of α-zirconium phosphate (α-ZrP) obtained from the reflux method in H3PO4 are successfully exfoliated into water via the intercalation of alkanol amines. With volume fractions greater than 0.02 they are stacked into tactoids of few layers with a repeat distance in the order of 10 nm. The tactoids align into nematic liquid crystalline phases with irregularly wide interstices of empty liquid. Colloidal processing involves the freeze-drying of such anisotropic fluids and the dispersion of the restacked tacoids into aqueous dispersions of colloidal polymer particles of largely varying size which occupy the otherwise empty liquid between the α-ZrP tactoids and induce piling of the tactoids into columns. Real-time SAXS on drying films and TEM of the obtained coatings demonstrate that the stacked α-ZrP platelets and the polymer particles comprising liquid dry separately without polymer intercalation, while the morphology of the obtained composites can be tuned primarily by the size of the polymer colloids. Concomitant α-ZrP hydrolysis in the exfoliation step is scrutinized as a function of amine basicity and temperature. The role of zirconium based hydrolysis products in the hierarchical α-ZrP assembly is indirectly though consistently confirmed by opposing impacts of ultra-filtration and added oxoanions on the platelets’ spacing, smoothness and aggregation. HAADF-TEM imaging of scattered, singular platelets and XRD peak analysis of the pristine solid shed light on the α-ZrP synthesis. Coexisting flakes and lacunae, both similar in size to the intra-layer crystal domains, suggest the stitching of proto-α-ZrP flakes into extended layers in accordance with our observations on the aging behaviour of α-ZrP dispersions as well as with literature data on related systems.

Use of light microscopy in the qualitative and quantitative study of liquid crystalline order

1992 ◽  
Vol 50 (1) ◽  
pp. 264-265
Author(s):  
Christopher Viney
Keyword(s):  
Light Microscopy ◽  
Liquid Crystalline ◽  
Structural Characteristics ◽  
Molecular Order ◽  
Liquid Crystalline Phases ◽  
Convenient Technique ◽  
Liquid Crystalline Materials ◽  
Transparent Windows

Light microscopy is a convenient technique for characterizing molecular order in fluid liquid crystalline materials. Microstructures can usually be observed under the actual conditions that promote the formation of liquid crystalline phases, whether or not a solvent is required, and at temperatures that can range from the boiling point of nitrogen to 600°C. It is relatively easy to produce specimens that are sufficiently thin and flat, simply by confining a droplet between glass cover slides. Specimens do not need to be conducting, and they do not have to be maintained in a vacuum. Drybox or other controlled environmental conditions can be maintained in a sealed chamber equipped with transparent windows; some heating/ freezing stages can be used for this purpose. It is relatively easy to construct a modified stage so that the generation and relaxation of global molecular order can be observed while specimens are being sheared, simulating flow conditions that exist during processing. Also, light only rarely affects the chemical composition or molecular weight distribution of the sample. Because little or no processing is required after collecting the sample, one can be confident that biologically derived materials will reveal many of their in vivo structural characteristics, even though microscopy is performed in vitro.

Electron microscopy and diffraction of crystalline dendrimers and macrocycles

1993 ◽  
Vol 51 ◽  
pp. 1218-1219
Author(s):  
C. J. Buchko ◽  
P. M. Wilson ◽  
Z. Xu ◽  
J. Zhang ◽  
S. Lee ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Liquid Crystalline ◽  
Structural Information ◽  
High Resolution Electron Microscopy ◽  
Scanning Calorimetry ◽  
Tertiary Butyl ◽  
Phenyl Acetylene ◽  
Selected Area Electron Diffraction ◽  
Liquid Crystalline Phases ◽  
Resolution Electron

The synthesis of well-defined organic molecules with unique geometries opens new opportunities for understanding and controlling the organization of condensed matter. Here, we study dendrimers and macrocycles which are synthesized from rigid phenyl-acetylene spacer units, Both units are solubilized by the presence of tertiary butyl groups located at the periphery of the molecule. These hydrocarbon materials form crystalline and liquid crystalline phases which have been studied by differential scanning calorimetry, hot stage optical microscopy, and wide-angle x-ray scattering (WAXS).The precisely defined architecture of these molecules makes it possible to investigate systematic variations in chemical architecture on the nature of microstructural organization. Here we report on the transmission electron microscopy (TEM), selected area electron diffraction (SAED), and high resolution electron microscopy (HREM) studies of crystalline thin films formed by deposition of these materials onto carbon substrates from dilute solution. Electron microscopy is very attractive for gaining structural information on new molecules due to the scarcity of material to grow single crystals suitable for conventional crystallography.

The Role of Zinc in Thyroid Hormones Metabolism

2019 ◽  
Vol 89 (1-2) ◽  
pp. 80-88 ◽  
Author(s):  
Juliana Soares Severo ◽  
Jennifer Beatriz Silva Morais ◽  
Taynáh Emannuelle Coelho de Freitas ◽  
Ana Letícia Pereira Andrade ◽  
Mayara Monte Feitosa ◽  
...  
Keyword(s):  
Thyroid Hormones ◽  
Scientific Evidence ◽  
Thyroid Stimulating Hormone ◽  
Zinc Transporters ◽  
Serum Concentrations ◽  
Metabolic Adaptations ◽  
Serum T3 ◽  
Regulatory Effects ◽  
Shed Light

Abstract. Thyroid hormones play an important role in body homeostasis by facilitating metabolism of lipids and glucose, regulating metabolic adaptations, responding to changes in energy intake, and controlling thermogenesis. Proper metabolism and action of these hormones requires the participation of various nutrients. Among them is zinc, whose interaction with thyroid hormones is complex. It is known to regulate both the synthesis and mechanism of action of these hormones. In the present review, we aim to shed light on the regulatory effects of zinc on thyroid hormones. Scientific evidence shows that zinc plays a key role in the metabolism of thyroid hormones, specifically by regulating deiodinases enzymes activity, thyrotropin releasing hormone (TRH) and thyroid stimulating hormone (TSH) synthesis, as well as by modulating the structures of essential transcription factors involved in the synthesis of thyroid hormones. Serum concentrations of zinc also appear to influence the levels of serum T3, T4 and TSH. In addition, studies have shown that Zinc transporters (ZnTs) are present in the hypothalamus, pituitary and thyroid, but their functions remain unknown. Therefore, it is important to further investigate the roles of zinc in regulation of thyroid hormones metabolism, and their importance in the treatment of several diseases associated with thyroid gland dysfunction.

The Adult as Foe or Friend?: Childism in Guus Kuijer's Criticism and Fiction

2013 ◽  
Vol 6 (2) ◽  
pp. 205-217 ◽  
Author(s):  
Vanessa Joosen
Keyword(s):  
Children's Literature ◽  
Children’S Literature ◽  
Age Groups ◽  
Children's Books ◽  
Children’S Books ◽  
Memorial Award ◽  
Adult Reader ◽  
Shed Light ◽  
Selection Of

Compared to the attention that children's literature scholars have paid to the construction of childhood in children's literature and the role of adults as authors, mediators and readers of children's books, few researchers have made a systematic study of adults as characters in children's books. This article analyses the construction of adulthood in a selection of texts by the Dutch author and Astrid Lindgren Memorial Award winner Guus Kuijer and connects them with Elisabeth Young-Bruehl's recent concept of ‘childism’ – a form of prejudice targeted against children. Whereas Kuijer published a severe critique of adulthood in Het geminachte kind [The despised child] (1980), in his literary works he explores a variety of positions that adults can take towards children, with varying degrees of childist features. Such a systematic and comparative analysis of the way grown-ups are characterised in children's texts helps to shed light on a didactic potential that materialises in different adult subject positions. After all, not only literary and artistic aspects of children's literature may be aimed at the adult reader (as well as the child), but also the didactic aspect of children's books can cross over between different age groups.

Tax evasion in the medical profession An Empirical Study in the General Tax Authority in Iraq

2019 ◽  
Vol 118 (11) ◽  
pp. 80-88
Author(s):  
Ramyar Rzgar Ahmed ◽  
Hawkar Qasim Birdawod ◽  
S. Rabiyathul Basariya
Keyword(s):  
Tax Evasion ◽  
Income Tax ◽  
Medical Profession ◽  
Great Influence ◽  
Tax Law ◽  
Degree Of Confidence ◽  
Medical Professions ◽  
Shed Light

The study dealt with tax evasion in the medical profession, where the problem was the existence of many cases of tax evasion, especially tax evasion in the income tax of medical professions. The aim of the study is to try to shed light on the phenomenon of tax evasion and the role of the tax authority in the development of controls and means that reduce the phenomenon of tax evasion. The most important results of the low level of tax awareness and lack of knowledge of the tax law and the unwillingness to read it and the sense of taxpayers unfairness of the tax all lead to an increase in cases of tax evasion and in suggested tightening control and follow-up on the offices of auditors, through the investigation and auditing The reports of certified accountants and the use of computers for this purpose in order to raise the degree of confidence in these reports and bring them closer to the required truth and coordination and cooperation with the Union of Accountants and Auditors and inform them about each case of violations of the auditors and accountants N because of its great influence in the rejection of the organization of the accounts and not to ratify fake accounts lead to show taxpayers accounts on a non-truth in order to tax evasion.

The Baluch, Sunnism and the State in Iran

2017 ◽  
Author(s):  
Stéphane A. Dudoignon
Keyword(s):  
South Asia ◽  
South Asian ◽  
Social Life ◽  
The State ◽  
First Century ◽  
Local Democracy ◽  
Oasis Area ◽  
Shed Light

Since 2002, Sunni jihadi groups have been active in Iranian Baluchistan without managing to plunge the region into chaos. This book suggests that a reason for this, besides Tehran’s military responses, has been the quality of Khomeini and Khamenei’s relationship with a network of South-Asia-educated Sunni ulama (mawlawis) originating from the Sarbaz oasis area, in the south of Baluchistan. Educated in the religiously reformist, socially conservative South Asian Deoband School, which puts the madrasa at the centre of social life, the Sarbazi ulama had taken advantage, in Iranian territory, of the eclipse of Baluch tribal might under the Pahlavi monarchy (1925-79). They emerged then as a bulwark against Soviet influence and progressive ideologies, before rallying to Khomeini in 1979. Since the turn of the twenty-first century, they have been playing the role of a rampart against Salafi propaganda and Saudi intrigues. The book shows that, through their alliance with an Iranian Kurdish-born Muslim-Brother movement and through the promotion of a distinct ‘Sunni vote’, they have since the early 2000s contributed towards – and benefitted from – the defence by the Reformist presidents Khatami (1997-2005) and Ruhani (since 2013) of local democracy and of the minorities’ rights. They endeavoured to help, at the same time, preventing the propagation of jihadism and Sunni radicalisation to Iran – at least until the ISIS/Daesh-claimed attacks of June 2017, in Tehran, shed light on the limits of the Islamic Republic’s strategy of reliance on Deobandi ulama and Muslim-Brother preachers in the country’s Sunni-peopled peripheries.

Wetlands Explained

2001 ◽  
Author(s):  
William M. Lewis
Keyword(s):  
Public Attitudes ◽  
Conservation Policy ◽  
Compact Form ◽  
The Political ◽  
Social Conflicts ◽  
Science And Policy ◽  
Ecosystem Science ◽  
Wetland Regulation ◽  
Shed Light

This book brings together in compact form a broad scientific and sociopolitical view of US wetlands. This primer lays out the science and policy considerations to help in navigating this branch of science that is so central to conservation policy, ecosystem science and wetland regulation. It gives explanations of the attributes, functions and values of our wetlands and shows how and why public attitudes toward wetlands have changed, and the political, legal, and social conflicts that have developed from legislation intended to stem the rapid losses of wetlands. The book describes the role of wetland science in facilitating the evolution of a rational and defensible system for regulating wetlands and will shed light on many of the problems and possibilities facing those who quest to protect and conserve our wetlands.

Islam, Gender, and Democracy in Comparative Perspective

2017 ◽  
Keyword(s):  
Human Rights ◽  
Comparative Literature ◽  
Gender Equality ◽  
Gender Inequality ◽  
Women's Rights ◽  
Women’S Rights ◽  
Muslim Countries ◽  
And Gender ◽  
Shed Light

This volume reframes the debate around Islam and women’s rights within a broader comparative literature. It examines the complex and contingent historical relationships between religion, secularism, democracy, law, and gender equality. Part I addresses the nexus of religion, law, gender, and democracy through different disciplinary perspectives (sociology, anthropology, political science, law). Part II localizes the implementation of this nexus between law, gender, and democracy, and provides contextualized responses to questions raised in Part I. The contributors explore the situation of Muslim women’s rights vis-à-vis human rights to shed light on gender politics in the modernization of the nation and to ponder over the role of Islam in gender inequality across different Muslim countries.

scholarly journals The European Committee of the Regions as a watchdog of the principle of subsidiarity

2020 ◽  
Vol 27 (3) ◽  
pp. 284-301
Author(s):  
Salvatore Fabio Nicolosi ◽  
Lisette Mustert
Keyword(s):  
European Commission ◽  
Legislative Process ◽  
European Committee ◽  
Legislative Proposal ◽  
The Right ◽  
Committee Of The Regions ◽  
Regional Funds ◽  
Shed Light ◽  
The Eu

In a resolution adopted on 1 February 2018, the European Committee of the Regions noted that a legislative proposal of the European Commission concerning a Regulation that changes the rules governing the EU regional funds for 2014-2020 did not comply with the principle of subsidiarity. Accordingly, the Committee considered challenging the legislative proposal before the Court of Justice if the proposal was formally agreed upon. Although at a later stage the European Commission decided to take into account the Committee’s argument and amended the proposal accordingly, such a context offers the chance to investigate more in detail the role of the Committee of the Regions in the legislative process of the EU and, more in particular, its role as a watchdog of the principle of subsidiarity. This paper aims to shed light on a rather neglected aspect of the EU constitutional practice, such as the potential of the Committee of the Regions to contribute to the legislative process, and answer the question of whether this Committee is the right body to guarantee compliance with the principle of subsidiarity.

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