ChemInform Abstract: A SYSTEMATIC INVESTIGATION OF THE REACTION OF SILICON DIFLUORIDE WITH ETHYLENE AND SIX METHYL-SUBSTITUTED ETHYLENES. II. CHARACTERIZATION OF POLYMERIC PRODUCTS, OPEN CHAIN ORGANOSILICON DERIVATIVES, AND 1,2-DISILACYCLOBUTANES

1980 ◽  
Vol 11 (30) ◽  
Author(s):  
W. F. REYNOLDS ◽  
J. C. THOMPSON ◽  
A. P. G. WRIGHT
Keyword(s):  
Systematic Investigation ◽  
Open Chain

A systematic investigation of the reaction of SiF2 with ethylene and six methyl-substituted ethylenes. II. Characterization of polymeric products, open chain organosilicon derivatives, and 1,2-disilacyclobutanes

1980 ◽  
Vol 58 (5) ◽  
pp. 425-435 ◽  
Author(s):  
William F. Reynolds ◽  
James C. Thompson ◽  
A. P. Gerald Wright
Keyword(s):  
Nmr Spectroscopy ◽  
Chemical Shift ◽  
Chemical Shifts ◽  
Systematic Investigation ◽  
Open Chain ◽  
Alkyl Substitution ◽  
Tail Structure

Polymers produced by the reaction of SiF2 with olefins have been characterized by 13C and 29Si nmr spectroscopy and have been found to have a regular head-to-tail structure with isolated SiF2 groups between olefin units. Only minor proportions of Si2F4 units are formed. The open chain organosilicon derivatives formed in the reaction are, with one exception, isomers of 1,2-disilacyclohexanes. The 1,2-disilacyclobutanes are formed stereospecifically with retention of alkyl stereochemistry. 19F chemical shifts can be predicted by additive chemical shift parameters for the effect of alkyl substitution.

Synthesis of sandwich type acyclic tetra-nuclear silver(I)-N-heterocyclic carbene complexes for wound healing applications

2020 ◽  
Vol 75 (9-10) ◽  
pp. 369-376
Author(s):  
Ayesha Riaz ◽  
Muhammad Adnan Iqbal ◽  
Haq Nawaz Bhatti ◽  
Muhammad Shahid
Keyword(s):  
Alkyl Halides ◽  
Wound Contraction ◽  
Spectroscopic Techniques ◽  
Open Chain ◽  
Standard Drug ◽  
Sandwich Type ◽  
Benzimidazolium Salts ◽  
Multistep Reaction

AbstractTwo meta-xylyl linked tetrakis-benzimidazolium salts (L1-L2) as multidentate ligands and two respective silver complexes (C1 and C2) were synthesized. A multistep reaction was done at room temperature, starting with simple benzimidazole and alkyl halides, going through precursors and salt formation by reflux and finally in situ deprotonation of tetrabenzimidazolium salts with Ag2O to yield respective tetra-nuclear Ag(I)-N-heterocyclic Carbene (NHC) complexes. Propyl and butyl groups were bonded at the terminal positions of tetra-azolium open chain salts. Characterization of compounds was done by analytical and spectroscopic techniques. On the basis of spectroscopic data, a chemical structure with open chains having four Ag(I) ions sandwiched between NHC layers was established. Potential of synthesized complexes (C1 & C2) for wound contraction was evaluated and compared with standard wound contraction gel. Percentage wound contraction of both complexes was found very close to that of standard drug used in parallel.

Systematic discovery and characterization of stress-related microRNA genes in Oryza sativa

Biologia ◽  
2015 ◽  
Vol 70 (1) ◽  
Author(s):  
Kai Bin Xie ◽  
Xue Zhou ◽  
Tian Hai Zhang ◽  
Bao Long Zhang ◽  
Li Ming Chen ◽  
...  
Keyword(s):  
Abiotic Stress ◽  
Stress Responses ◽  
Systematic Investigation ◽  
Chemical Toxicity ◽  
Promoter Regions ◽  
Crop Species ◽  
Translation Inhibition ◽  
Microrna Genes ◽  
Insight Into

AbstractAbiotic stresses including drought, salinity, extreme temperatures, chemical toxicity and oxidative are the natural status of the environment to exert serious threats to agriculture. Abiotic stress-related microRNAs (ASmiRNAs) are a group of microRNAs (miRNAs) regulating stress responses in plants. However, the systematic investigation of ASmiRNAs is limited in Rice (O. sativa), a typical abiotic stress-resistant crop species. In the present work, we systematically investigated ASmiRNAs in silico. First, we identified 177 putative ASmiRNAs in O.sativa. Second, we found most ASmiRNAs were driven by TATA-promoter and most stress-related miRNA promoter regions contained the stress-related elements. Third, we found many ASmiRNAs families were species/family specific and a set of miRNAs might derive from genomic repeat-sequences in O. sativa. Finally, we found the ASmiRNAs in O. sativa target 289 genes with 1050 predicted target sites in which 98% sites have cleavage activity and 2% sites have translation inhibition activity. In conclusion, our findings provide an insight into both the function and evolution of ASmiRNAs and improve our understanding on the mechanism of abiotic stress resistance in O. sativa.

Application of Atom Probe Microanalysis for Understanding Microstructure Evolution in Nickel Base Superalloy Welds

2000 ◽  
Vol 6 (S2) ◽  
pp. 350-351
Author(s):  
S. S. Babu ◽  
S. A. David ◽  
M. K. Miller
Keyword(s):  
Microstructure Evolution ◽  
Predictive Models ◽  
Strong Relationship ◽  
Atom Probe ◽  
Systematic Investigation ◽  
Nickel Base Superalloy ◽  
Cooling Conditions ◽  
Nickel Base ◽  
Base Superalloy

The characterization of the microstructure evolution during welding of nickel base superalloys is required for efficient reuse and reclamation of used and failed components. Previous atom probe analysis of electron-beam and laser-beam welds revealed complex alloying elemental partitioning between the γ and γ phases. Rapid cooling conditions in the weld leads to non-equilibrium partitioning and large amplitude Cr and Co levels in the γ phase. These results indicated that there is a strong relationship between weld cooling rate and the precipitation of γ′ precipitates from the γ phase. To understand and develop predictive models, a systematic investigation of the microstructure evolution in CM247DS alloy under controlled thermomechanical conditions are being performed. This paper describes some recent results on the elemental partitioning between γ and γ′ phases obtained with atom probe microanalysis.

On the Structure of Certain Nest Algebra Modules

1987 ◽  
Vol 39 (6) ◽  
pp. 1405-1412
Author(s):  
G. J. Knowles
Keyword(s):  
Operator Algebras ◽  
Adjoint Operator ◽  
Systematic Investigation ◽  
Unique Determination ◽  
Nest Algebra ◽  
Minimal Elements ◽  
Open Questions ◽  
Weakly Closed ◽  
Order Homomorphisms

Let be a nest algebra of operators on some Hilbert space H. Weakly closed -modules were first studied by J. Erdos and S. Power in [4]. It became apparent that many interesting classes of non self-adjoint operator algebras arise as just such a module. This paper undertakes a systematic investigation of the correspondence which arises between such modules and order homomorphisms from Lat into itself. This perspective provides a basis to answer some open questions arising from [4]. In particular, the questions concerning unique “determination” and characterization of maximal and minimal elements under this correspondence, are resolved. This is then used to establish when the determining homomorphism is unique.

scholarly journals Synthesis and Characterization of Acridinium Dyes for Photoredox Catalysis

Synlett ◽  
2019 ◽  
Vol 30 (07) ◽  
pp. 827-832 ◽  
Author(s):  
Alexander White ◽  
Leifeng Wang ◽  
David Nicewicz
Keyword(s):  
Photophysical Properties ◽  
Direct Conversion ◽  
Systematic Investigation ◽  
Synthetic Methods ◽  
Synthesis And Characterization ◽  
Substitution Effects ◽  
Photoredox Catalysis ◽  
Methods Development

Photoredox catalysis is a rapidly evolving platform for synthetic methods development. The prominent use of acridinium salts as a sustainable option for photoredox catalysts has driven the development of more robust and synthetically useful versions based on this scaffold. However, more complicated syntheses, increased cost, and limited commercial availability have hindered the adoption of these catalysts by the greater synthetic community. By utilizing the direct conversion of a xanthylium salt into the corresponding acridinium as the key transformation, we present an efficient and scalable preparation of the most synthetically useful acridinium reported to date. This divergent strategy also enabled the preparation of a suite of novel acridinium dyes, allowing for a systematic investigation of substitution effects on their photophysical properties.

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