Search results for "Moi"
showing 10 items of 2109 documents
Revealing interactions between polyaza pyridinophane compounds and DNA/RNA polynucleotides by SERS spectroscopy
2014
Surface-enhanced Raman scattering spectroscopy (SERS) in the near-infrared region had been applied to study interactions of polyaza pyridinophanes with single stranded RNA and double stranded DNA and RNA polynucleotides. Studied compounds, PYPOD and PHENPOD, differed in the central aromatic moiety, pyridine and phenanthroline, respectively, which linked two cyclic amines. An intense scattering was obtained from molecules adsorbed onto the silver nanoparticles, showing nonlinear concentration dependence in the 6.5 × 10−8−6.5 × 10−5 M range. New bands in spectra of PYPOD/polynucleotide and PHENPOD/polynucleotide mixtures were assigned to vibrational modes of polynucleotide moieties involved i…
Transamidation reactions of 2-(2-sulfonylguanidino)acetamides
2007
Abstract The reactivity of a series of sulfonylguanidinoacetamides 2A–E towards amines is reported. Guanidinoacetamides 2A–C, containing the arylsulfonylimino moiety, undergo a facile transamidation to give substituted carboxamides 4A–C, through the imidazolidinone intermediate 3. Acetamide 2D, having a methanesulfonylimino substituent, affords the imidazolidinone 3D and no transamidated carboxamides 4 are detected. In the case of guanidinoacetamide 2E, with a p-nitrobenzenesulfonylimino substituent, a Smiles rearrangement was observed.
New Optically Active 4-Alkoxyprolinol Ethers Derived from trans-4-Hydroxy-L-proline
2011
(2S,4R)-trans-4-Hydroxy-L-proline has been used as thechiral-pool source in the efficient syntheses of optically active protected 4-hydroxyprolinols. After N-acyl protection andester formation, the first ether moiety was introduced maintaining the chiral centre adjacent to the ester. Then, reduction of the ester delivered the corresponding carbinol, which had to be alkylated selectively to avoid side reactions with the N-protecting group. Finally, the N-acyl function was removed to generate the target methyl and tert-butyl ethers displaying defined substitution patterns. The so-formed optically active 4-alkoxyprolinol ethers can be used as core fragments in biologically active compounds or …
Controlling Spin-Correlated Radical Pairs with Donor-Acceptor Dyads: A New Concept to Generate Reduced Metal Complexes for More Efficient Photocataly…
2021
Abstract One‐electron reduced metal complexes derived from photoactive ruthenium or iridium complexes are important intermediates for substrate activation steps in photoredox catalysis and for the photocatalytic generation of solar fuels. However, owing to the heavy atom effect, direct photochemical pathways to these key intermediates suffer from intrinsic efficiency problems resulting from rapid geminate recombination of radical pairs within the so‐called solvent cage. In this study, we prepared and investigated molecular dyads capable of producing reduced metal complexes via an indirect pathway relying on a sequence of energy and electron transfer processes between a Ru complex and a cova…
Nickel as a Lewis Base in a T‐Shaped Nickel(0) Germylene Complex Incorporating a Flexible Bis(NHC) Ligand
2018
Flexible, chelating bis(NHC) ligand 2, able to accommodate both cis- and trans-coordination modes, was used to synthesize (2)Ni(η 2 -cod), 3. In reaction with GeCl2, this produced (2)NiGeCl2, 4, featuring a T-shaped Ni(0) and a pyramidal Ge center. Complex 4 could also be prepared from [(2)GeCl]Cl, 5, and Ni(cod)2, in a reaction that formally involved Ni-Ge transmetalation, followed by coordination of the extruded GeCl2 moiety to Ni. A computational analysis showed that 4 possesses considerable multiconfigurational character and the Ni→Ge bond is formed through σ-donation from the Ni 4s, 4p, and 3d orbitals to Ge. (NHC)2Ni(cod) complexes 9 and 10, as well as (NHC)2GeCl2 derivative 11, incor…
Playing with different metalloligands [NiL] and Hg to [NiL] ratios to tune the nuclearity of Ni(II)–Hg(II) complexes: Formation of di-, tri-, hexa- a…
2015
Abstract Five new hetero-metallic nickel(II)–mercury(II) complexes, [(NiL1)HgCl2] (1), [(NiL1)2HgCl2] (3), [(NiL1)2Hg(N3)2] (4), [{(NiL2)2Hg(N3)(μ1,1-N3)}2] (5) and [{(NiL2)2Hg(N3)(μ1,1-N3)HgCl2}2{Hg(N3)(μ1,1-N3)}] (6) have been synthesized by reacting metalloligands [NiL1] or [NiL2] (where H2L1 is N,N′-bis(salicylidene)-1,2-ethylenediamine and H2L2 is N,N′-bis(salicylidene)-1,3-propanediamine) with HgX2 (X− = Cl− or N3−) at different molar ratios. All five complexes have been characterised by X-ray single-crystal structural, elemental and spectroscopic analyses. In complex 1, the Hg(II) ion is coordinated to two phenoxido oxygen atoms of one [NiL1] moiety and two terminal chloride ions to …
LE CISTI EPIDERMOIDI DELLA MILZA
1993
Le cisti epidermoidi della ilza sono rare e rappresentano appena il 10% della patologia cistica non parassitaria. Viene presentato un caso occorso in una piccola paziente di 6 anni, sottoposta a splenectomia per le enormi dimensioni della cisti e per la sua posizione anomale sull'ilo.
Changes in Climate and Land Use Over the Amazon Region: Current and Future Variability and Trends
2018
This paper shows recent progress in our understanding of climate variability and trends in the Amazon region, and how these interact with land use change. The review includes an overview of up-to-date information on climate and hydrological variability, and on warming trends in Amazonia, which reached 0.6-0.7 °C over the last 40 years, with 2016 as the warmest year since at least 1950 (0.9 °C +0.3°C). We focus on local and remote drivers of climate variability and change. We review the impacts of these drivers on the length of dry season, the role of the forest in climate and carbon cycles, the resilience of the forest, the risk of fires and biomass burning, and the potential “die back” of …
The pedagogy of multiliteracies as a code breaker : A suggestion for a transversal approach to computing education in basic education
2021
While computing has been (re)introduced into the basic education curricula in various countries, its actual implementation appears to be inconsistent. There are schools in which computing education is commonplace, while the implementation seems to be lagging behind in others. There is emerging evidence that some teachers do not consider computing education relevant, meaningful and important and, thus, intentionally neglect its provision. This is problematic as understanding the principles of code and computing is crucial for agentic citizenship in the post-digital era. This paper argues that one main reason for these teachers' reluctance is the economy-driven discursive framing of computing…
A Methodology for Protection of Trees Against Lightning Strikes as a Measure to Prevent Fires and Loss of Human Life
2021
Some regions may be characterized by a very low annual lightning ground flash density, and yet lightning strikes seem to have been in those areas the cause of widespread wildfires in forested areas. Due to global climate change, these occurrences seem to be an increasing threat. In this paper, the authors discuss the withstand capability of trees against lightning and introduce the criteria for the deployment of tree lightning protection systems (TLPS) to protect forested areas, where deemed necessary by the tree risk assessment. This work analytically identifies the critical trunk radius of the tree below which the tree may explode in the case of a lightning strike and ignite the surroundi…