Search results for "modification"

Measurement of charged jet production cross sections and nuclear modification in p–Pb collisions at √sNN=5.02 TeV

2015

Charged jet production cross sections in p–Pb collisions at √sNN = 5.02 TeV measured with the ALICE detector at the LHC are presented. Using the anti-kT algorithm, jets have been reconstructed in the central rapidity region from charged particles with resolution parameters R = 0.2 and R = 0.4. The reconstructed jets have been corrected for detector effects and the underlying event background. To calculate the nuclear modification factor, RpPb, of charged jets in p–Pb collisions, a pp reference was constructed by scaling previously measured charged jet spectra at √s = 7 TeV. In the transverse momentum range 20 ≤ pT, ch jet ≤ 120 GeV/c, RpPb is found to be consistent with unity, indicating th…

MODIFICA SUPERFICIALE DI FILM DI POLY(ETILENE-co-ACIDO ACRILICO) CON NANOPARTICELLE DI SILICE ATTIVATA

2009

Zirconocene-Based Methods for the Preparation of BN-Indenes : Application to the Synthesis of 1,5-Dibora-4a,8a-diaza-1,2,3,5,6,7-hexaaryl-4,8-dimethy…

2017

A method for the preparation of 3-bora-9aza-indene heterocycles based on zirconocene mediated functionalization of the ortho-CH bonds of pyridines has been developed and used to make two such compounds. Unlike other methods, the boron center in these heterocycles remains functionalized with a chloride ligand and so the compounds can be further elaborated through halide abstraction and reduction. The utility of the method was further demonstrated by applying it towards the preparation of 1,5- dibora-4a,8a-diaza BN analogues of the intriguing hydrocarbon s-indacene starting from 2,5-dimethylpyrazine. Gram quantities of one such compound was prepared and fully characterized, and both experimen…

Analysis of pseudouridines and other RNA modifications using hydraPsiSeq protocol

2021

Detection of RNA modified nucleotides using deep sequencing can be performed by several approaches, including antibody-driven enrichment and natural or chemically induced RT signatures. However, only very few RNA modified nucleotides generate natural RT signatures and antibody-driven enrichment heavily depends on the quality of antibodies used and may be highly biased. Thus, the use of chemically-induced RT signatures is now considered as the most trusted experimental approach. In addition, the use of chemical reagents allows inclusion of simple "mock-treated" controls, to exclude spontaneous RT arrests, SNPs and other misincorporation-prone sites. Hydrazine is a well-known RNA-specific rea…

Mapping and Quantification of tRNA 2′-O-Methylation by RiboMethSeq

2018

Current development of epitranscriptomics field requires efficient experimental protocols for precise mapping and quantification of various modified nucleotides in RNA. Despite important advances in the field during the last 10 years, this task is still extremely laborious and time-consuming, even when high-throughput analytical approaches are employed. Moreover, only a very limited subset of RNA modifications can be detected and only rarely be quantified by these powerful techniques. In the past, we developed and successfully applied alkaline fragmentation-based RiboMethSeq approach for mapping and precise quantification of multiple 2'-O-methylation residues in ribosomal RNA. Here we descr…

Functionalization and patterning of reactive polymer brushes based on surface reversible addition and fragmentation chain transfer polymerization

2012

We present the synthesis of reactive polymer brushes prepared by surface reversible addition–fragmentation chain transfer polymerization of pentafluorophenyl acrylate. The reactive ester moieties can be used to functionalize the polymer brush film with virtually any functionality by simple post-polymerization modification with amines. Dithiobenzoic acid benzyl-(4-ethyltrimethoxylsilyl) ester was used as the surface chain transfer agent (S-CTA) and the anchoring group onto the silicon substrates. Reactive polymer brushes with adjustable molecular weight, high grafting density, and conformal coverage through the grafting-from approach were obtained. Subsequently, the reactive polymer brushes …

Substrate-Independent Stable and Adherent Reactive Surface Coatings and their Conversion with Amines

2007

To create stable, adherent and reactive surface coatings, a hybrid polymer composed of poly(methylsilsesquioxane) (PMSSQ) and poly(pentafluorophenyl acrylate) PFPA with a M n of 32000 g/mol was prepared by a RAFT polymerization procedure. These hybrid polymer has been used for coating experiments. The PFPA part enabled a variable functionalization of the coating afterwards. The stability on various substrates (e.g. glass, PMMA, steel) was tested in an ISO tape test. These reactive surface coatings were modified using different amines, such as amino-terminated PEG, dodecyl amine and N-isopropyl amine. The conversion was analyzed by FT-IR and contact angle measurements.

Versatile Responsive Surfaces via Hybrid Polymers Containing Acetal Side Groups

2009

Two hybrid polymers, poly(methylsilsesquioxane)-poly(2,2-diethoxyethyl acrylate) and poly-(methylsilsesquioxane)-poly(1,3-dioxolan-2-ylmethyl acrylate), were synthesized and used for preparation of stable surface coatings. Their acetal side groups could be functionalized via solution-dipping with different primary amines and hydroxylamines after acidic deprotection and thus allowed for flexible modification of the surface hydrophilicity. Functionalization with a thermo-responsive polymer resulted in a thermo-responsive surface with temperature-dependent contact angles. Further, the two types of acetals showed different stability toward acidic treatment and could be addressed independently.

Glycidyl methacrylate derivatization of α,β-poly(N-hydroxyethyl)-dl-aspartamide and α,β-polyasparthydrazide

1997

Abstract α,β-Poly(N-hydroxyethyl)- dl -aspartamide (PHEA) and α,β-polyasparthydrazide (PAHy) are two synthetic macromolecules having many potential applications in the field of biomedical sciences. This paper describes the functionalization of PHEA and PAHy with glycidyl methacrylate (GMA), in order to introduce pendant double bonds in their chains. Derivatized PHEA and PAHy (samples PHG and PAG, respectively) at various GMA content have been obtained and characterized. It has been shown that the derivatization reaction can be controlled by varying some parameters as solvent, catalyst, pH, GMA concentration and reaction time. As expected, PAHy reacted more rapidly and more extensively than …

Photochemical Functionalization of Allyl Benzoates by C-H Insertion

2013

The photoreactivity of allyl benzoates, containing an electron-rich double bond, has been explored by irradiation at 305 nm in different solvents. Solvent addition products arising from an insertion of the alpha H–C bonds of THF, dioxane, and i-PrOH to the allylic double bond was realized. The observed reactivity depended on reaction conditions and substitution pattern of the substrate. A DFT study on this unusual reaction was performed allowing the formulation of two mechanistic pathways.