Structural characteristics requisite for the ligand-based selective detection of i-motif DNA

2019 ◽  
Vol 17 (21) ◽  
pp. 5392-5399 ◽  
Author(s):  
Sagar Satpathi ◽  
Subrahmanyam Sappati ◽  
Konoya Das ◽  
Partha Hazra
Keyword(s):  
Structural Characteristics ◽  
Selective Detection ◽  
Base Pairing ◽  
New Approach ◽  
Dna Structures ◽  
Chain Lengths ◽  
Protonated Cytosine

A new approach has been explored to detect i-motif DNA structures over its complementary GQ DNA based on the hemi-protonated cytosine–cytosine (C+–C) base pairing recognition. This approach also shows its versatility by detecting various i-motif DNA structures with different chain lengths, molecularity and sizes, etc.

Factors Affecting Molecular Self-Assembly and Its Mechanism

2012 ◽  
Vol 9 (1) ◽  
pp. 43 ◽  
Author(s):  
Hueyling Tan
Keyword(s):  
Self Assembly ◽  
Building Blocks ◽  
Molecular Engineering ◽  
Molecular Structures ◽  
Polymer Science ◽  
New Approach ◽  
Factors Affecting ◽  
Dna Structures ◽  
Self Assembling ◽  
Wide Range

Molecular self-assembly is ubiquitous in nature and has emerged as a new approach to produce new materials in chemistry, engineering, nanotechnology, polymer science and materials. Molecular self-assembly has been attracting increasing interest from the scientific community in recent years due to its importance in understanding biology and a variety of diseases at the molecular level. In the last few years, considerable advances have been made in the use ofpeptides as building blocks to produce biological materials for wide range of applications, including fabricating novel supra-molecular structures and scaffolding for tissue repair. The study ofbiological self-assembly systems represents a significant advancement in molecular engineering and is a rapidly growing scientific and engineering field that crosses the boundaries ofexisting disciplines. Many self-assembling systems are rangefrom bi- andtri-block copolymers to DNA structures as well as simple and complex proteins andpeptides. The ultimate goal is to harness molecular self-assembly such that design andcontrol ofbottom-up processes is achieved thereby enabling exploitation of structures developed at the meso- and macro-scopic scale for the purposes oflife and non-life science applications. Such aspirations can be achievedthrough understanding thefundamental principles behind the selforganisation and self-synthesis processes exhibited by biological systems.

scholarly journals Interaction between DNA and Trimethyl-Ammonium Bromides with Different Alkyl Chain Lengths

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Chao Cheng ◽  
Shi-Yong Ran
Keyword(s):  
Surfactant Concentration ◽  
Alkyl Chain ◽  
Scattering Method ◽  
High Concentration ◽  
Dna Structures ◽  
Dynamic Light Scattering Method ◽  
Atomic Force ◽  
Chain Lengths ◽  
Dna Complex ◽  
Long Alkyl Chain

The interaction betweenλ—DNA and cationic surfactants with varying alkyl chain lengths was investigated. By dynamic light scattering method, the trimethyl-ammonium bromides-DNA complex formation was shown to be dependent on the length of the surfactant’s alkyl chain. For surfactants with sufficient long alkyl chain (CTAB, TTAB, DTAB), the compacted particles exist with a size of ~60–110 nm at low surfactant concentrations. In contrast, high concentration of surfactants leads to aggregates with increased sizes. Atomic force microscope scanning also supports the above observation. Zeta potential measurements show that the potential of the particles decreases with the increase of surfactant concentration (CTAB, TTAB, DTAB), which contributes much to the coagulation of the particles. For OTAB, the surfactant with the shortest chain in this study, it cannot fully neutralize the charges of DNA molecules; consequently, the complex is looser than other surfactant-DNA structures.

Establishment and application of an assembly dimension model based on shortest path

2016 ◽  
Vol 232 (3) ◽  
pp. 525-533 ◽  
Author(s):  
Youli Wang ◽  
Xiaohui Wang ◽  
Xueliang Zhang ◽  
Jianmei Wang
Keyword(s):  
High Precision ◽  
Shortest Path ◽  
Structural Characteristics ◽  
Ball Screw ◽  
New Approach ◽  
Functional Dimension ◽  
Model Based ◽  
Path Graph ◽  
Full Dimension ◽  
Correlative Dimension

This article presents a new approach for obtaining unique dimensioning for each part and building a full-dimension model of assembly dimensions by describing the formative paths of functional dimensions in an assembly. According to the structure and the functional dimensions of an assembly, as well as the principles that ‘the path should be the shortest’, ‘high precision should be given priority’ and ‘one surface can appear only once in the path graph’, the shortest path graph of the functional dimensions can be established first, ensuring that every functional dimension has minimum accumulative errors. The revised path graph is obtained by revising the shortest path graph according to structural characteristics, inspection and dimensioning regulation of parts. In this way, unique dimensioning is achieved for each part, and a full correlative dimension model can be established. A gearbox assembly and a ball screw assembly are used to verify the proposed method, but this article discusses only the assembly that is generally located in a certain direction. Over-location, planar or spatial assemblies require further research.

scholarly journals Més enllà de la doble hèlix: L’estructura G-quàdruplex de l’ADN

2021 ◽  
Author(s):  
Isabel Pont ◽  
Jorge Gonzàlez-Garcia
Keyword(s):  
Double Helix ◽  
Structural Characteristics ◽  
Cancer Therapies ◽  
Cellular Functions ◽  
Dna Structures ◽  
G Quadruplex ◽  
Neural Information ◽  
Double Helix Structure ◽  
And Control ◽  
Tetramer Structure

DNA is the fundamental biomolecule needed for correct cell functioning and, until very recently, it was associated to the double helix structure discovered over 70 years ago by Crick, Watson, and Franklin. However, other DNA structures and conformations have been described, like G-quadruplexes. These G-quadruplexes are formed in regions of the genome that are rich in guanine. They have tetramer structure and control biological processes such as genetic expression, protection against ageing, or the transmission of neural information. In this document, we describe their chemical and structural characteristics, besides presenting their main cellular functions. Lastly, we present G-quadruplexes as molecular targets for future cancer therapies.

Measuring Structural Change

2019 ◽  
pp. 348-362
Author(s):  
Célestin Monga ◽  
Samuel Standaert
Keyword(s):  
Structural Change ◽  
Structural Transformation ◽  
Comparative Advantage ◽  
Structural Characteristics ◽  
New Approach ◽  
Outcome Index ◽  
The Individual ◽  
Traditional Approaches ◽  
New Structural Economics

This chapter examines the specific problems that arise when creating an index of structural change and development, and offers recommendations to address them. It first considers the four steps to composing a policy index and an outcome index: define what the index is trying to measure; identify suitable indicators that track (parts of) the definition decided upon in the first step; normalize the individual indicators and aggregate them into the final index; and analyse the index and report on the results. The chapter then discusses traditional approaches to measuring structural transformation, along with their shortcomings, before introducing a new approach. Insights from New Structural Economics are highlighted, including the argument that the desired structural characteristics of countries are determined by their comparative advantage, which in turn depends on their level of development.

Effect of Amine Molecular Chain Length on the Mechanical and Thermal Properties of Functionalized Graphene Oxide/Polyurea Nanocomposites

2021 ◽  
Vol 13 (2) ◽  
pp. 199-208
Author(s):  
Qiang Zhao ◽  
Si Ouyang ◽  
Gang Chen ◽  
Yiqing Deng ◽  
Mengxiao Chen ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Chemical Conversion ◽  
Mechanical And Thermal Properties ◽  
Functionalized Graphene ◽  
Scanning Calorimetry ◽  
Functionalized Graphene Oxide ◽  
New Approach ◽  
Chain Lengths

To improve the overall performance of polyurea, linear diamines with three different chain lengths (1,2-ethylenediamine (EDA) and amino-terminated polyoxypropylenes D230 and D2000) were reacted with graphene oxide (GO) by reaction of amines with carboxyl groups, and three different amino-functionalized graphene oxide (AGO) nanosheets (EDA-GO, D230-GO and D2000-GO) were prepared. Subsequently, an AGO flake was bonded to a polyurea (PUA) substrate by an in situ chemical process. Analytical tests, including X-ray photoelectron spectroscopy (XPS), showed that diamines were attached to the GO flake. The reinforcement properties of the nanocomposites were investigated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and tensile testing. AGO nanosheets, especially EDA-GO, result in a certain degree of enhancement in the thermal and mechanical properties of nanocomposites formed with polyurea. The TGA and DSC results indicated that the T5% and Tg of the nanocomposites at low AGO loading were increased compared with those of pure polyurea. Meanwhile, the elongation at break of the nanocomposite film with 0.1 wt% EDA-GO loading was 240% higher than that of pure polyurea, and tensile strength was increased by 80% over that of pure polyurea. We provide a new approach to the chemical conversion of GO/PUA nanocomposites by preparing AGO and complexing it with polyurea.

scholarly journals Rule-based modeling using wildcards

2017 ◽  
Author(s):  
Steven S. Andrews
Keyword(s):  
Reaction Network ◽  
Distinct Species ◽  
Unintended Consequences ◽  
Biological Molecules ◽  
Post Translational Modifications ◽  
Rule Based ◽  
New Approach ◽  
Signaling Systems ◽  
Formal Rule ◽  
Chain Lengths

SummaryMany biological molecules exist in multiple variants, such as proteins with different post-translational modifications, DNAs with different sequences, and phospholipids with different chain lengths. Representing these variants as distinct species, as most biochemical simulators do, leads to the problem that the number of species, and chemical reactions that interconvert them, typically increase combinatorially with the number of ways that the molecules can vary. This can be alleviated by “rule-based modeling methods,” in which software generates the chemical reaction network from relatively simple “rules.” This article presents a new approach to rule-based modeling. It is based on wildcards that match to species names, much as wildcards can match to file names in computer operating systems. It is much simpler to use than the formal rule-based modeling approaches developed previously but can also lead to unintended consequences if not used carefully. This article demonstrates rule-based modeling with wildcards through examples for: signaling systems, protein complexation, polymerization, nucleic acid sequence copying and mutation, the “SMILES” chemical notation, and others. The method is implemented in Smoldyn, a spatial and stochastic biochemical simulator, for both the generate-first and on-the-fly expansion, meaning whether the reaction network is generated before or during the simulation.

scholarly journals Towards Quantum-Chemical Modeling of the Activity of Anesthetic Compounds

2021 ◽  
Vol 22 (17) ◽  
pp. 9272
Author(s):  
Janusz Cukras ◽  
Joanna Sadlej
Keyword(s):  
Perturbation Theory ◽  
Lipid Rafts ◽  
Intermolecular Interactions ◽  
Quantum Chemical ◽  
Structural Characteristics ◽  
Point Of View ◽  
Chemical Modeling ◽  
New Approach ◽  
Real Challenge ◽  
Insight Into

The modeling of the activity of anesthetics is a real challenge because of their unique electronic and structural characteristics. Microscopic approaches relevant to the typical features of these systems have been developed based on the advancements in the theory of intermolecular interactions. By stressing the quantum chemical point of view, here, we review the advances in the field highlighting differences and similarities among the chemicals within this group. The binding of the anesthetics to their partners has been analyzed by Symmetry-Adapted Perturbation Theory to provide insight into the nature of the interaction and the modeling of the adducts/complexes allows us to rationalize their anesthetic properties. A new approach in the frame of microtubule concept and the importance of lipid rafts and channels in membranes is also discussed.

scholarly journals Beyond the Census Tract: Patterns and Determinants of Racial Segregation at Multiple Geographic Scales

2008 ◽  
Vol 73 (5) ◽  
pp. 766-791 ◽  
Author(s):  
Barrett A. Lee ◽  
Sean F. Reardon ◽  
Glenn Firebaugh ◽  
Chad R. Farrell ◽  
Stephen A. Matthews ◽  
...  
Keyword(s):  
Residential Segregation ◽  
Census Tract ◽  
Census Data ◽  
Structural Characteristics ◽  
Racial Segregation ◽  
Geographic Scale ◽  
Spatial Concepts ◽  
New Approach ◽  
Local Environments ◽  
Hispanic White

The census tract—based residential segregation literature rests on problematic assumptions about geographic scale and proximity. We pursue a new tract-free approach that combines explicitly spatial concepts and methods to examine racial segregation across egocentric local environments of varying size. Using 2000 Census data for the 100 largest U.S. metropolitan areas, we compute a spatially modified version of the information theory index H to describe patterns of Black—White, Hispanic-White, Asian-White, and multigroup segregation at different scales. We identify the metropolitan structural characteristics that best distinguish micro-segregation from macro-segregation for each group combination, and we decompose their effects into portions due to racial variation occurring over short and long distances. A comparison of our results with those from tract-based analyses confirms the value of the new approach.

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