scholarly journals Discussions of Fluorescence in Selenium Chemistry: Recently Reported Probes, Particles, and a Clearer Biological Knowledge

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 692
Author(s):  
Ariq Abdillah ◽  
Prasad M. Sonawane ◽  
Donghyeon Kim ◽  
Dooronbek Mametov ◽  
Shingo Shimodaira ◽  
...  
Keyword(s):  
Thin Film ◽  
Small Molecule ◽  
Active Site ◽  
Metal Ion ◽  
Biological Knowledge ◽  
Oxide Nanoparticles ◽  
Redox Biology ◽  
The Past ◽  
Catalyst Poisons ◽  
The Relationship

In this review from literature appearing over about the past 5 years, we focus on selected selenide reports and related chemistry; we aimed for a digestible, relevant, review intended to be usefully interconnected within the realm of fluorescence and selenium chemistry. Tellurium is mentioned where relevant. Topics include selenium in physics and surfaces, nanoscience, sensing and fluorescence, quantum dots and nanoparticles, Au and oxide nanoparticles quantum dot based, coatings and catalyst poisons, thin film, and aspects of solar energy conversion. Chemosensing is covered, whether small molecule or nanoparticle based, relating to metal ion analytes, H2S, as well as analyte sulfane (biothiols—including glutathione). We cover recent reports of probing and fluorescence when they deal with redox biology aspects. Selenium in therapeutics, medicinal chemistry and skeleton cores is covered. Selenium serves as a constituent for some small molecule sensors and probes. Typically, the selenium is part of the reactive, or active site of the probe; in other cases, it is featured as the analyte, either as a reduced or oxidized form of selenium. Free radicals and ROS are also mentioned; aggregation strategies are treated in some places. Also, the relationship between reduced selenium and oxidized selenium is developed.

scholarly journals Restructuring polymers via nanoconfinement and subsequent release

2012 ◽  
Vol 8 ◽  
pp. 1318-1332 ◽  
Author(s):  
Alan E Tonelli
Keyword(s):  
Small Molecule ◽  
Polymer Chains ◽  
Crystalline Lattice ◽  
Host Molecule ◽  
Nanostructured Polymers ◽  
Narrow Channels ◽  
The Past ◽  
The Relationship ◽  
Melting And Crystallization Temperatures ◽  
Melting And Crystallization

During the past several years my students and I have been utilizing certain small-molecule hosts to create nanostructured polymers. This is accomplished by first forming noncovalently bonded inclusion complexes (ICs) between these small-molecule hosts and guest polymers, followed by the careful removal of the host crystalline lattice to obtain a coalesced bulk polymer. We have repeatedly observed that such coalesced polymer samples behave distinctly from those produced from their solutions or melts. Coalesced amorphous homopolymers exhibit higher glass-transition temperatures, while crystallizable homopolymers coalesced from their ICs display higher melting and crystallization temperatures, and sometimes different crystalline polymorphs. When ICs are formed with block copolymers or with two or more different homopolymers, the resulting coalesced samples can exhibit intimate mixing between the copolymer blocks, or between entire homopolymer chains. Each of the distinct behaviors observed for polymers coalesced from their ICs is a consequence of the structural organization of the polymer–host-ICs. Polymer chains in host-IC crystals are confined to occupy narrow channels (diameter ~0.5–1.0 nm) formed by the small-molecule hosts around the included guest polymers during IC crystallization. This results in the separation and high extension of the included guest polymer chains, which leads, following the careful removal of the host molecule lattice, to unique behaviors for the bulk coalesced polymer samples. Apparently, substantial degrees of the extended and unentangled natures of the IC-included chains are retained upon coalescence. In this review we summarize the behaviors and uses of coalesced polymers, and attempt to draw conclusions on the relationship between their behavior and the organization/structures/conformations of the constituent polymer chains achieved upon coalescence from their ICs.

scholarly journals Identification of a Pyridoxine-Derived Small-Molecule Inhibitor Targeting Dengue Virus RNA-Dependent RNA Polymerase

2015 ◽  
Vol 60 (1) ◽  
pp. 600-608 ◽  
Author(s):  
Hong-Tao Xu ◽  
Susan P. Colby-Germinario ◽  
Said Hassounah ◽  
Peter K. Quashie ◽  
Yingshan Han ◽  
...  
Keyword(s):  
Drug Design ◽  
Dengue Virus ◽  
Rna Polymerase ◽  
Small Molecule ◽  
Active Site ◽  
Metal Ion ◽  
Rdrp Activity ◽  
Rna Dependent Rna Polymerase ◽  
Molecule Inhibitor ◽  
Hiv 1

ABSTRACTThe viral RNA-dependent RNA polymerase (RdRp) activity of the dengue virus (DENV) NS5 protein is an attractive target for drug design. Here, we report the identification of a novel class of inhibitor (i.e., an active-site metal ion chelator) that acts against DENV RdRp activity. DENV RdRp utilizes a two-metal-ion mechanism of catalysis; therefore, we constructed a small library of compounds, through mechanism-based drug design, aimed at chelating divalent metal ions in the catalytic site of DENV RdRp. We now describe a pyridoxine-derived small-molecule inhibitor that targets DENV RdRp and show that 5-benzenesulfonylmethyl-3-hydroxy-4-hydroxymethyl-pyridine-2-carboxylic acid hydroxyamide (termed DMB220) inhibited the RdRp activity of DENV serotypes 1 to 4 at low micromolar 50% inhibitory concentrations (IC50sof 5 to 6.7 μM) in an enzymatic assay. The antiviral activity of DMB220 against DENV infection was also verified in a cell-based assay and showed a 50% effective concentration (EC50) of <3 μM. Enzyme assays proved that DMB220 was competitive with nucleotide incorporation. DMB220 did not inhibit the enzymatic activity of recombinant HIV-1 reverse transcriptase and showed only weak inhibition of HIV-1 integrase strand transfer activity, indicating high specificity for DENV RdRp. S600T substitution in the DENV RdRp, which was previously shown to confer resistance to nucleoside analogue inhibitors (NI), conferred 3-fold hypersusceptibility to DMB220, and enzymatic analyses showed that this hypersusceptibility may arise from the decreased binding/incorporation efficiency of the natural NTP substrate without significantly impacting inhibitor binding. Thus, metal ion chelation at the active site of DENV RdRp represents a viable anti-DENV strategy, and DMB220 is the first of a new class of DENV inhibitor.

Structures of c-di-GMP/cGAMP degrading phosphodiesterase VcEAL: identification of a novel conformational switch and its implication

2019 ◽  
Vol 476 (21) ◽  
pp. 3333-3353 ◽  
Author(s):  
Malti Yadav ◽  
Kamalendu Pal ◽  
Udayaditya Sen
Keyword(s):  
Active Site ◽  
Metal Binding ◽  
Metal Ion ◽  
Triosephosphate Isomerase ◽  
Catalytic Mechanism ◽  
Degradation Mechanism ◽  
Structural Basis ◽  
Conserved Residues ◽  
Phosphodiester Bond ◽  
Cyclic Dinucleotides

Cyclic dinucleotides (CDNs) have emerged as the central molecules that aid bacteria to adapt and thrive in changing environmental conditions. Therefore, tight regulation of intracellular CDN concentration by counteracting the action of dinucleotide cyclases and phosphodiesterases (PDEs) is critical. Here, we demonstrate that a putative stand-alone EAL domain PDE from Vibrio cholerae (VcEAL) is capable to degrade both the second messenger c-di-GMP and hybrid 3′3′-cyclic GMP–AMP (cGAMP). To unveil their degradation mechanism, we have determined high-resolution crystal structures of VcEAL with Ca2+, c-di-GMP-Ca2+, 5′-pGpG-Ca2+ and cGAMP-Ca2+, the latter provides the first structural basis of cGAMP hydrolysis. Structural studies reveal a typical triosephosphate isomerase barrel-fold with substrate c-di-GMP/cGAMP bound in an extended conformation. Highly conserved residues specifically bind the guanine base of c-di-GMP/cGAMP in the G2 site while the semi-conserved nature of residues at the G1 site could act as a specificity determinant. Two metal ions, co-ordinated with six stubbornly conserved residues and two non-bridging scissile phosphate oxygens of c-di-GMP/cGAMP, activate a water molecule for an in-line attack on the phosphodiester bond, supporting two-metal ion-based catalytic mechanism. PDE activity and biofilm assays of several prudently designed mutants collectively demonstrate that VcEAL active site is charge and size optimized. Intriguingly, in VcEAL-5′-pGpG-Ca2+ structure, β5–α5 loop adopts a novel conformation that along with conserved E131 creates a new metal-binding site. This novel conformation along with several subtle changes in the active site designate VcEAL-5′-pGpG-Ca2+ structure quite different from other 5′-pGpG bound structures reported earlier.

Poor Acceptance of the Past is Related to Depressive Symptoms in Older Adults

GeroPsych ◽  
2020 ◽  
Vol 33 (4) ◽  
pp. 246-251
Author(s):  
Gozde Cetinkol ◽  
Gulbahar Bastug ◽  
E. Tugba Ozel Kizil
Keyword(s):  
Older Adults ◽  
Regression Analysis ◽  
Depressive Symptoms ◽  
Death Anxiety ◽  
Geriatric Depression ◽  
Ego Integrity ◽  
The Past ◽  
Depressed Group ◽  
Total Death ◽  
The Relationship

Abstract. Depression in older adults can be explained by Erikson’s theory on the conflict of ego integrity versus hopelessness. The study investigated the relationship between past acceptance, hopelessness, death anxiety, and depressive symptoms in 100 older (≥50 years) adults. The total Beck Hopelessness (BHS), Geriatric Depression (GDS), and Accepting the Past (ACPAST) subscale scores of the depressed group were higher, while the total Death Anxiety (DAS) and Reminiscing the Past (REM) subscale scores of both groups were similar. A regression analysis revealed that the BHS, DAS, and ACPAST predicted the GDS. Past acceptance seems to be important for ego integrity in older adults.

A literature review on firms' internationalisation through e-commerce

2019 ◽  
pp. 121-143
Author(s):  
Riccardo Resciniti ◽  
Federica De Vanna
Keyword(s):  
Systematic Review ◽  
Literature Review ◽  
International Business ◽  
Decision Process ◽  
Foreign Markets ◽  
New Markets ◽  
Integrative Framework ◽  
The Past ◽  
The Relationship

The rise of e-commerce has brought considerable changes to the relationship between firms and consumers, especially within international business. Hence, understanding the use of such means for entering foreign markets has become critical for companies. However, the research on this issue is new and so it is important to evaluate what has been studied in the past. In this study, we conduct a systematic review of e-commerce and internationalisation studies to explicate how firms use e-commerce to enter new markets and to export. The studies are classified by theories and methods used in the literature. Moreover, we draw upon the internationalisation decision process (antecedents-modalities-consequences) to propose an integrative framework for understanding the role of e-commerce in internationalisation

Policy Making Introduction

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
Nina TERREY ◽  
Sabine JUNGINGER
Keyword(s):  
Policy Implementation ◽  
Policy Making ◽  
Creative Industries ◽  
Design Management ◽  
Support Design ◽  
The Past ◽  
Academic Researchers ◽  
Design Activities ◽  
The Relationship ◽  
Professional Impact

The relationship that exists between design, policies and governance is quite complex and presents academic researchers continuously with new opportunities to engage and explore aspects relevant to design management. Over the past years, we have witnessed how the earlier focus on developing policies for design has shifted to an interest in understanding the ways in which design contributes to policy-making and policy implementation. Research into policies for design has produced insights into how policy-making decisions can advance professional impact and opportunities for designers and the creative industries. This research looked into how design researchers and design practitioners themselves can benefit from specific policies that support design activities and create the space for emerging design processes.

Diversification propaganda work with foreign audiences

2020 ◽  
Vol 4 (4(13)) ◽  
pp. 31-50
Author(s):  
Shiyu Zhang ◽  
Keyword(s):  
Developing Countries ◽  
International Relations ◽  
Strategic Partnership ◽  
The Past ◽  
Bilateral Relations ◽  
The Media ◽  
The Relationship

Over the past decade, bilateral relations between China and Russia have attracted the attention of the whole world. As neighbors and rapidly developing countries, China and Russia are becoming increasingly important in the international arena. The strategic partnership and interaction between China and Russia occupy a significant place in the politics of both countries. Cooperation is developing dynamically in various fields, primarily in politics. After 2012, a change of government took place in China and Russia, which brought new changes to international relations. Studying the involvement of the media in this process can clarify their impact on international relations, in particular, their role in the relationship between China and Russia.

О вопросах фольклоризма в письменной литературе

2019 ◽  
pp. 31-33
Author(s):  
Суусар Искендерова
Keyword(s):  
Modern Science ◽  
Folk Songs ◽  
Point Of View ◽  
The Past ◽  
Scientific Term ◽  
Literature Culture ◽  
Definition Of ◽  
The Relationship

Аннотация: Исследование проблемы фольклоризма является наиболее актуальной в современной науке о фольклоре. На разных этапах развития художественной литературы для формирования индивидуального творчества писателя особенно значимым становятся фольклорные жанры, сюжетные мотивы и художественные средства. В статье рассматривается связь письменной литературы и фольклора, особенно точка зрения проблеме фольклоризма в прошлом и их анализ. Термин «фольклоризм» начал использоваться советскими исследователями учеными как научный термин еще в 1930-х гг. Термин «фольклоризм» используется в различных сферах культуры, а в этой статье мы будем рассматривать в литературе. Несмотря на то, что на протяжении многих лет этот вопрос изучается литературоведами, фольклористами, все -таки нет единого теоретического определения понятия. Ключевые слова: фольклор, фольклоризм, литература, культура, письменная литература, художественная литература, оседлый народ, пословицы и поговорки, фольклорные песни. Аннотация: Көркөм адабияттын өнүгүүсүнүн ар кайсы баскычтарында сүрөткердин жеке чыгармачылыгынын калыптанышы үчүн фольклордук жанрлар, сюжеттер, мотивдер жана көркөм каражаттар айрыкча мааниге ээ. Макалада жазма адабият менен фольклордук карым-катышы, айрыкча фольклоризм маселеси жөнүндө мурдагы көз караштарга кайрылып, аларга талдоо жүргүзүү менен бирге автор өз байкоолорунда келтирет. “Фольклоризм” деген илимий термин 1930-жылы баштап колдонула баштаган. “Фольклоризм” термини маданияттын түрдүү сфераларында кеңири колдо- нулат, бул жерде адабияттагы колдонулушун каралат. Макалада адабий материал менен фольклордук байланышын терең түшүнүү үчүн адабий фольклоризм маселесинин талаштуу жактары каралат. Түйүндүү сөздөр: фольклор, фольклоризм, адабият, маданият, жазма адабият, көркөм адабият, көчмөн калк, макал-лакап, фольклордук ырлар. Annotation: The study of the problem of folklore is the most relevant in the modern science of folklore. At various stages in the development of fiction, folklore genres, plot motifs, and artistic means become especially significant for the formation of the writer's individual creativity. The article examines the relationship between written literature and folklore, especially the point of view of the problem of folklorism in the past and their analysis. The term "folklorism" began to be used by Soviet scholars as a scientific term back in the 1930s. The term "folklorism" is used in various fields of culture, and in this article we will consider in the literature. Despite the fact that for many years this issue has been studied by literary scholars, folklorists, all the same there is no single theoretical definition of the concept. Keywords: folklore, folklorism, literature, culture, written literature, fiction, settled people, proverbs and sayings, folk songs.

Oleanolic Acid Derived from Plants: Synthesis and Pharmacological Properties of A-ring Modified Derivatives

2020 ◽  
Vol 17 (9) ◽  
pp. 1084-1101
Author(s):  
Tingjuan Wu ◽  
Xu Yao ◽  
Guan Wang ◽  
Xiaohe Liu ◽  
Hongfei Chen ◽  
...  
Keyword(s):  
Drug Design ◽  
Oleanolic Acid ◽  
Water Solubility ◽  
Future Application ◽  
The Novel ◽  
Pharmacological Effects ◽  
Framework Structure ◽  
Design And Synthesis ◽  
The Past ◽  
The Relationship

Background: Oleanolic Acid (OA) is a ubiquitous product of triterpenoid compounds. Due to its inexpensive availability, unique bioactivities, pharmacological effects and non-toxic properties, OA has attracted tremendous interest in the field of drug design and synthesis. Furthermore, many OA derivatives have been developed for ameliorating the poor water solubility and bioavailability. Objective: Over the past few decades, various modifications of the OA framework structure have led to the observation of enhancement in bioactivity. Herein, we focused on the synthesis and medicinal performance of OA derivatives modified on A-ring. Moreover, we clarified the relationship between structures and activities of OA derivatives with different functional groups in A-ring. The future application of OA in the field of drug design and development also was discussed and inferred. Conclusion: This review concluded the novel achievements that could add paramount information to the further study of OA-based drugs.

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