scholarly journals Thermochemical and Structural Analysis of Tautomers of Sulfur and Selenium Modified RNA Nucleobases

2019 ◽  
Vol 2 (2) ◽  
pp. 47-48
Author(s):  
Megan Joy ◽  
Alex Brown ◽  
Arturo Mora Gomez ◽  
Maria Rossano-Tapia ◽  
Shyam Parshotam
Keyword(s):  
Ir Spectra ◽  
Structural Changes ◽  
Chemical Properties ◽  
Hydrogen Atoms ◽  
Relative Population ◽  
Geometry Analysis ◽  
Physical And Chemical ◽  
Modified Nucleobases ◽  
Relative Gibbs Free Energy ◽  
And Chemical Properties

Nucleobases (adenine, cytosine, guanine, and uracil), the four molecules that forms RNA, have been found to be useful in probing in the human body when modified because they can emit light. Non-modified nucleobases do not exhibit emissive properties and cannot be used as probes. Some of the modifications include the substitution of nitrogen atoms with sulfur and selenium, and the resulting modified nucleobases give place to the so-called tz- and ts- RNA alphabets, respectively. Therefore, the aim of this project was to provide insights about the viability, from a computational perspective, of using the modified nucleobases as probes, evaluating the differences in thermochemical, structural and emissive properties of the modified nucleobases with respect to the non-modified ones. Nucleobases can coexist with other modified nucleobases or tautomers, molecules that differ due to the change in position of hydrogen atoms in a molecule’s structure and as a result have different physical and chemical properties. The thermochemical properties evaluation mainly consisted in the computation of the relative Gibbs Free Energy (G), which is related to the fraction F, an index of the relative population among tautomers. This was done using Gaussian 09 software by performing geometry analysis and frequency computations on each one of the tautomers. By comparing the equilibrium fractions, it was determined that in both cases, tz- and ts- guanine and cytosine exist principally in the form of one of their tautomers (Cytosine 2 and Guanine 2) as in the case of the non-modified cases. After confirming which tz- and ts- tautomers were the ones with the largest probable population, infrared (IR) and ultraviolet-visible (UV-vis) spectra were obtained. The IR spectra of selenium and sulfur tautomers of guanine and cytosine indicated that the tautomers had peaks at similar frequencies with respect to each other, however, the intensities varied, implying slight structural changes between the tautomers. On the other hand, the UV-vis spectra showed a change in peak positions between the tautomers with sulfur and selenium, suggesting that the change between sulfur and selenium has an effect on the spectra by shifting the peaks from the original molecules’ λmax values. Their relative population fractions show that only the canonical forms of the modified nucleobases exist in a larger extent than the rest of their tautomer forms. In addition, the features in their UV-vis and IR spectra allow these tautomers to be differentiated from each other.

Experimental Investigation on Grinding Temperature of Titanium Alloy

2014 ◽  
Vol 1027 ◽  
pp. 127-130 ◽  
Author(s):  
Bing Jun Hao ◽  
Zhi Gang Dong ◽  
Ren Ke Kang ◽  
Huan Wang ◽  
Ke Cao
Keyword(s):  
Titanium Alloy ◽  
Structural Changes ◽  
Thermal Damage ◽  
Elevated Temperatures ◽  
Chemical Properties ◽  
Grinding Temperature ◽  
Physical And Chemical Properties ◽  
Machine Material ◽  
Physical And Chemical ◽  
And Chemical Properties

Titanium alloy has been widely used in aeronautics and astronautics industry owing to its unique combinations of properties. The unique physical and chemical properties of titanium alloy make it a typical difficult-to-machine material. The elevated temperatures at the machining zones may cause thermal damage, residual stress and micro-structural changes in the surface layer of titanium alloy during grinding. In this study, grinding experiments were performed on the titanium alloy, and the grinding temperature was experimentally tested with the grindable thermocouples. The effects of the grinding parameters on the grinding temperature were analyzed. The grinding temperature rises with the increase of grinding speed and grinding depth.

Tuning Packing, Structural Flexibility, and Porosity in 2D Metal–Organic Frameworks by Metal Node Choice

2019 ◽  
Vol 72 (10) ◽  
pp. 797 ◽  
Author(s):  
Witold M. Bloch ◽  
Christian J. Doonan ◽  
Christopher J. Sumby
Keyword(s):  
Structural Changes ◽  
Metal Organic Frameworks ◽  
Chemical Properties ◽  
Complete Removal ◽  
Structural Flexibility ◽  
X Ray Diffraction ◽  
Metal Centre ◽  
Metal Organic ◽  
Physical And Chemical ◽  
And Chemical Properties

Understanding the key features that determine structural flexibility in metal–organic frameworks (MOFs) is key to exploiting their dynamic physical and chemical properties. We have previously reported a 2D MOF material, CuL1, comprising five-coordinate metal nodes that displays exceptional CO2/N2 selectively (L1=bis(4-(4-carboxyphenyl)-1H-pyrazolyl)methane). Here we examine the effect of utilising six-coordinate metal centres (CoII and NiII) in the synthesis of isostructural MOFs from L1, namely CoL1 and NiL1. The octahedral geometry of the metal centre within the MOF analogues precludes an ideal eclipse of the 2D layers, resulting in an offset stacking, and in certain cases, the formation of 2-fold interpenetrated analogues β-CoL1 and β-NiL1. We used a combination of thermogravimetric analysis (TGA), and powder and single crystal X-ray diffraction (PXRD and SCXRD) to show that desolvation is accompanied by a structural change for NiL1, and complete removal of the coordinated H2O ligands results in a reduction in long-range order. The offset nature of the 2D layers in combination with the structural changes impedes the adsorption of meaningful quantities of gases (N2, CO2), highlighting the importance of a five-coordinate metal centre in achieving optimal pore accessibility for this family of flexible materials.

scholarly journals Compounds of Complex Halo and Pseudohalo Acids of the Group II B Metals, Part I Etherate, Pyridine and Aniline Compounds of Zn(II)

1979 ◽  
Vol 34 (8) ◽  
pp. 1101-1106 ◽  
Author(s):  
A. G. Galinos ◽  
J. K . Kouinis ◽  
P. V. Ioannou ◽  
Th. F . Zafiropoulos ◽  
S. P. Perlepes
Keyword(s):  
Solid State ◽  
Ir Spectra ◽  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Uv And Ir Spectra ◽  
Group Ii ◽  
Physical And Chemical ◽  
And Chemical Properties

The preparation of sixteen new etherate, pyridine and aniline compounds of complex halo and pseudohalo acids of Zn(II) is reported.The study of some physical and chemical properties as well as the UV and IR spectra of these compounds are discussed. Tetrahedral structures are proposed for all compounds in the solid state

scholarly journals Synthesis of Picric Acid at Domestic Scales.

2019 ◽  
Author(s):  
Afshan Saleem ◽  
Noureen Rafi ◽  
Sumara Qasim ◽  
Usama Ashraf ◽  
Nasir Hussain Virk
Keyword(s):  
Ir Spectra ◽  
Physical State ◽  
Picric Acid ◽  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Greenish Yellow ◽  
Yellow Color ◽  
Physical And Chemical ◽  
Derivatives Of ◽  
And Chemical Properties

Picric acid and its derivatives are widely used in various applications/industries. The first synthetic dye was prepared in 1771 using picric acid. It was used to dye silk fabric into greenish-yellow color. In this study, Picric acid and their derivatives were synthesized and characterized by their physical and chemical properties. The derivatives of Picric acid which are considered in this research include Picramic acid and Sodium Picramate. The physical properties like melting point, colors, physical state and solubility of Picric acid and its derivatives were determined and confirmed using IR Spectra. IR spectra proved efficient in scanning and mapping.

Effects of interaction between montmorillonite and Sphingomonas sp. GY2B on the physical and chemical properties of montmorillonite in the clay-modulated biodegradation of phenanthrene

2018 ◽  
Vol 15 (5) ◽  
pp. 296 ◽  
Author(s):  
Bo Ruan ◽  
Pingxiao Wu ◽  
Huimin Wang ◽  
Liping Li ◽  
Langfeng Yu ◽  
...  
Keyword(s):  
Physicochemical Properties ◽  
Structural Changes ◽  
Morphological Changes ◽  
Chemical Properties ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Valuable Insight ◽  
Physical And Chemical Properties ◽  
Physical And Chemical ◽  
And Chemical Properties

Environmental contextInteractions between microbes and minerals can influence geochemical reactions, and hence are of fundamental importance in natural environmental processes. We investigate the effects of Sphingomonas sp. on the structure and physicochemical properties of montmorillonite, a common clay mineral, and determine how this interaction influences the biodegradation of phenanthrene. The findings have profound impact on the clay-modulated biodegradation of organic compounds in the environment. AbstractWe investigate the effect of Sphingomonas sp. GY2B on the structure and physicochemical properties of montmorillonite (Mt). The simultaneous biodegradation of a polycyclic aromatic hydrocarbon compound, phenanthrene, was also monitored. After interaction with bacteria for 2 days, the increases of the specific surface area (SSA) and micropore volume, differences of the thermogravimetric analysis and differential scanning calorimetry (TGA-DSC) patterns and the morphological changes revealed modification of the physicochemical properties and mineral surface. Although the interlayer spacing of Mt remained unchanged, the appearance and shift of several vibration peaks in the Fourier transform infrared (FTIR) spectra confirmed the structural changes of Mt arising from bacterial activities. Concentrations of the major elements of montmorillonite changed greatly in the aqueous solution, especially Si, Al, Fe and Ca. Based on the analyses of X-ray diffraction (XRD) and FTIR, these changes were mainly ascribed to the formation of precipitates and minerals in the biotic experiment. Changes in the release rate of different elements also substantiated that the GY2B strain has a considerable impact on the dissolution of montmorillonite. Additionally, a preferential release of Si and the 27Al and 29Si cross-polarisation magic-angle spinning nuclear magnetic resonance (CP/MAS NMR) spectra of bacteria-untreated samples demonstrated that tetrahedral sheets were preferentially destroyed and octahedral sheets in montmorillonite were dissolved. These results showed that microorganisms can greatly affect the physical and chemical properties of clay minerals in the clay-modulated biodegradation of hydrophobic organic contaminants. This study provides valuable insight into the clay-modulated microbial remediation of organic pollutants in the environment.

scholarly journals Repertoire of morphable proteins in an organism

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8606
Author(s):  
Keisuke Izumi ◽  
Eitaro Saho ◽  
Ayuka Kutomi ◽  
Fumiaki Tomoike ◽  
Tetsuji Okada
Keyword(s):  
Structural Biology ◽  
Structural Variation ◽  
Structural Changes ◽  
Global Analysis ◽  
Chemical Properties ◽  
E Coli ◽  
Cryo Electron Microscopy ◽  
Living Organisms ◽  
Physical And Chemical ◽  
And Chemical Properties

All living organisms have evolved to contain a set of proteins with variable physical and chemical properties. Efforts in the field of structural biology have contributed to uncovering the shape and the variability of each component. However, quantification of the variability has been performed mostly by multiple pair-wise comparisons. A set of experimental coordinates for a given protein can be used to define the “morphness/unmorphness”. To understand the evolved repertoire in an organism, here we show the results of global analysis of more than a thousand Escherichia coli proteins, by the recently introduced method, distance scoring analysis (DSA). By collecting a new index “UnMorphness Factor” (UMF), proposed in this study and determined from DSA for each of the proteins, the lowest and the highest boundaries of the experimentally observable structural variation are comprehensibly defined. The distribution plot of UMFs obtained for E. coli represents the first view of a substantial fraction of non-redundant proteome set of an organism, demonstrating how rigid and flexible components are balanced. The present analysis extends to evaluate the growing data from single particle cryo-electron microscopy, providing valuable information on effective interpretation to structural changes of proteins and the supramolecular complexes.

New Metal -Pentafluorothiophenol Compounds

1978 ◽  
Vol 33 (2) ◽  
pp. 149-150 ◽  
Author(s):  
D. M. Kaminaris ◽  
A. G. Galinos
Keyword(s):  
Ir Spectra ◽  
Analytical Data ◽  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Nonaqueous Solutions ◽  
New Compounds ◽  
Physical And Chemical ◽  
And Chemical Properties

In the present paper the reactions of pentafluorothiophenol with nonaqueous solutions (absolute n-hexane) of anhydrous AlCl3, FeBr3, RhCl3 and CrCl3 are described. Analytical data, some physical and chemical properties and the IR spectra of the new compounds are reported and discussed

Application of Infrared Absorption Spectra to Studies of the Oxidation of Sodium-Butadiene Rubber

1951 ◽  
Vol 24 (3) ◽  
pp. 591-596
Author(s):  
B. Dogadkin ◽  
B. Kasatochkin ◽  
N. Klauzen ◽  
A. Smirnova
Keyword(s):  
Quantitative Analysis ◽  
Molecular Oxygen ◽  
Structural Changes ◽  
Chemical Properties ◽  
Butadiene Rubber ◽  
Physical And Chemical Properties ◽  
Reaction Products ◽  
Infrared Absorption Spectra ◽  
Physical And Chemical ◽  
And Chemical Properties

Abstract The reaction of rubber with molecular oxygen explains well the structural changes which take place in rubber during aging and during a number of important technological processes, such as plasticization and vulcanization. Furthermore, during vulcanization, in addition to its reaction with the vulcanizing agent, rubber also reacts with oxygen contained in the mixture. This may be one of the reasons for an optimum point of vulcanization. However, it is difficult to explain the changes of physical properties of rubber by simple union of oxygen, with formation of oxygen-bearing groups. To account for the changes observed, addition of a large quantity of oxygen would be necessary, whereas actually notable changes are brought about by the absorption of only 2–3 per cent of oxygen. To explain this, it must be assumed that oxygen causes structural changes in rubber and that these changes become evident when the percentage of oxygen in the reaction products is still negligible. In the case of sodium-butadiene rubber, as was shown by one of the authors, this reaction at any particular temperature causes an increase of strength and of elasticity, and a loss of solubility. The object of the present investigation was a qualitative and limited quantitative analysis of those groups which originate during oxidation and also an examination of the structures which determine the changes of the physical and chemical properties in the reaction of rubber with molecular oxygen.

scholarly journals Development of Blue Emitting Organic Phosphors of Diphenylquionial (DPQ) Group for OLED

2021 ◽  
pp. 44-46
Author(s):  
G. D. Zade
Keyword(s):  
Structural Changes ◽  
Chemical Properties ◽  
Chemical Study ◽  
Blue Color ◽  
Display System ◽  
Organic Phosphors ◽  
The Stability ◽  
Physical And Chemical ◽  
Derivatives Of ◽  
And Chemical Properties

A Series of blue emitting organic phosphors and its derivatives with different combinations were synthesized in an argon atmosphere at 1400C by Friedlander Condensation method and are tested chemically for its solubility in acidic and basic and emitting blue color under UV. The structural changes take place in DPQ an organic phosphor. The structural, optical and chemical properties of all the derivatives of diphlnylquioline (DPQ) were studied from various characterizations. It shows the stability of characterized organic polymers. The physical and chemical study shows more effectiveness with large applications to emit blue light for organic display system.

Sign in / Sign up

Export Citation Format

Share Document