Influence of the glycosidic torsion angle on 13C and 15N shifts in guanosine nucleotides: Investigations of G-tetrad models with alternating syn and anti bases

1995 ◽  
Vol 5 (4) ◽  
Author(s):  
KarenL. Greene ◽  
Yong Wang ◽  
David Live
2016 ◽  
Vol 82 (1) ◽  
pp. 25-36 ◽  
Author(s):  
Takashi Hara ◽  
Tetsuya Kodama ◽  
Yumi Takegaki ◽  
Kunihiko Morihiro ◽  
Kosuke Ramon Ito ◽  
...  

Molbank ◽  
10.3390/m1227 ◽  
2021 ◽  
Vol 2021 (2) ◽  
pp. M1227
Author(s):  
Bibi Hanifa ◽  
Muhammad Sirajuddin ◽  
Zafran Ullah ◽  
Sumera Mahboob ◽  
See Mun Lee ◽  
...  

The synthesis and spectroscopic characterization of the glutaric acid-amide derivative, 2,4-Cl2C6H3N(H)C(=O)(CH2)3C(=O)OH (1), are described. The X-ray crystal structure determination of (1) shows the backbone of the molecule to be kinked about the methylene-C–N(amide) bond as seen in the C(p)–N–C(m)–C(m) torsion angle of −157.0(2)°; m = methylene and p = phenyl. An additional twist in the molecule is noted between the amide and phenyl groups as reflected in the C(m)–N–C(p)–C(p) torsion angle of 138.2(2)°. The most prominent feature of the molecular packing is the formation of supramolecular tapes assembled through carboxylic acid-O–H…O(carbonyl) and amide-N–H…O(amide) hydrogen bonding.


2021 ◽  
Vol 13 (8) ◽  
pp. 4255
Author(s):  
Mingmin Kong ◽  
Shuaiming Feng ◽  
Qi Xia ◽  
Chen Chen ◽  
Zhouxin Pan ◽  
...  

Hydrogen is of great significance for replacing fossil fuels and reducing carbon dioxide emissions. The application of hydrogen mixing with natural gas in gas network transportation not only improves the utilization rate of hydrogen energy, but also reduces the cost of large-scale updating household or commercial appliance. This paper investigates the necessity of a gas mixing device for adding hydrogen to existing natural gas pipelines in the industrial gas network. A three-dimensional helical static mixer model is developed to simulate the mixing behavior of the gas mixture. In addition, the model is validated with experimental results. Parametric studies are performed to investigate the effect of mixer on the mixing performance including the coefficient of variation (COV) and pressure loss. The research results show that, based on the, the optimum number of mixing units is three. The arrangement of the torsion angle of the mixing unit has a greater impact on the COV. When the torsion angle θ = 120°, the COV has a minimum value of 0.66%, and when the torsion angle θ = 60°, the COV has a maximum value of 8.54%. The distance of the mixing unit has little effect on the pressure loss of the mixed gas but has a greater impact on the COV. Consecutive arrangement of the mixing units (Case A) is the best solution. Increasing the distance of the mixing unit is not effective for the gas mixing effect. Last but not least, the gas mixer is optimized to improve the mixing performance.


2014 ◽  
Vol 70 (9) ◽  
pp. o1051-o1052 ◽  
Author(s):  
Ignez Caracelli ◽  
Stella H. Maganhi ◽  
Paulo J. S. Moran ◽  
Bruno R. S. de Paula ◽  
Felix N. Delling ◽  
...  

In the title compound, C17H14N2O6, the conformation about the C=C double bond [1.345 (2) Å] isE, with the ketone moiety almost coplanar [C—C—C—C torsion angle = 9.5 (2)°] along with the phenyl ring [C—C—C—C = 5.9 (2)°]. The aromatic rings are almost perpendicular to each other [dihedral angle = 86.66 (7)°]. The 4-nitro moiety is approximately coplanar with the benzene ring to which it is attached [O—N—C—C = 4.2 (2)°], whereas the one in theorthoposition is twisted [O—N—C—C = 138.28 (13)°]. The molecules associateviaC—H...O interactions, involving both O atoms from the 2-nitro group, to form a helical supramolecular chain along [010]. Nitro–nitro N...O interactions [2.8461 (19) Å] connect the chains into layers that stack along [001].


2012 ◽  
Vol 538-541 ◽  
pp. 1031-1034
Author(s):  
Er Ming He ◽  
Hong Wei Zhang ◽  
Zhi Bin Zhao

To solve the problems of complex bending parts forming, such as low efficiency and accuracy, and loss of modification experience data, the algorithm of three parameters segment springback modification (TPSSM) based on arc approximation is presented in this paper. Firstly, the centroid line is divided into several arc sections according to the requirement and each section is modified based on presumptive correcting factor of radius, torsion and torsion angle. Then based on UG re-development, the program and UI of TPSSM are developed with UG/Open API and MFC. Finally, experimental results show that this method can effectively realize springback modification of bending parts, which is worthy for practical engineering project.


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