244 research outputs found
NMR Chemical Shifts of Trace Impurities: Common Laboratory Solvents, Organics, and Gases in Deuterated Solvents Relevant to the Organometallic Chemist
Tables of ^1H and ^(13)C NMR chemical shifts have been compiled for common organic compounds often used as reagents or found as products or contaminants in deuterated organic solvents. Building upon the work of Gottlieb, Kotlyar, and Nudelman in the Journal of Organic Chemistry, signals for common impurities are now reported in additional NMR solvents (tetrahydrofuran-d_8, toluene-d_8, dichloromethane-d_2, chlorobenzene-d_5, and 2,2,2-trifluoroethanol-d_3) which are frequently used in organometallic laboratories. Chemical shifts for other organics which are often used as reagents or internal standards or are found as products in organometallic chemistry are also reported for all the listed solvents
{2,6-Bis[(di-tert-butylphosphino)methyl]phenyl}chloridonickel(II)
In the title compound, [Ni(C24H43P2)Cl], the Ni atom adopts a distorted square-planar geometry, with the P atoms of the 2,6-bis[(di-tert-butylphosphino)methyl]phenyl ligand trans to one another. The P—Ni—P plane is twisted out of the plane of the aromatic ring by 21.97 (6)°
[2,6-Bis(di-tert-butylphosphinomethyl)phenyl-κ3 P,C 1,P′](nitrato-κO)nickel(II)
The NiII atom in the title compound, [Ni(C24H43P2)(NO3)], adopts a distorted square-planar geometry with the P atoms in a trans arrangement. The compound contains a twofold rotational axis with the nitrate group offset from this axis, except for an O atom of the nitrate group, generating two positions of 50% occupancy for the other atoms of the nitrate group
Projeto gráfico-editorial de manual de entrega de originais na Imprensa Universitária da UFSC
PCC(graduação) - Universidade Federal de Santa Catarina. Centro de Comunicação e Expressão. Design.Este trabalho apresenta a elaboração do projeto gráfico-editorial do manual de entrega de arquivos da Imprensa Universitária da UFSC. O projeto foi desenvolvido com base na metodologia de design proposta por Bruce Archer e na metodologia de estruturação de projeto gráfico-editorial proposta por Castro e Sousa (2013). Cada etapa, do planejamento a execução, foi descrita de forma detalhada expondo a pesquisa, análise, definições e justificativas para a obtenção de um produto gráfico-editorial funcional, atraente e que atende às necessidades do público e da própria Imprensa Universitária.This paper presents the development graphic-editorial project of a guide for files delivery in the Imprensa Universitária of UFSC. The project was developed based on design methodology proposed by Bruce Archer and on the graphic-editorial methodology proposed by Castro and Sousa (2013). Each stage, from planning to execution, has been described in detail, exposing the research, analysis, definitions and justifications to the conception of a functional and attractive graphic-editorial product, that meets the needs of the public and the Imprensa Universitária itself
A signal from inside the peroxisome initiates its division by promoting the remodeling of the peroxisomal membrane
We define the dynamics of spatial and temporal reorganization of the team of proteins and lipids serving peroxisome division. The peroxisome becomes competent for division only after it acquires the complete set of matrix proteins involved in lipid metabolism. Overloading the peroxisome with matrix proteins promotes the relocation of acyl-CoA oxidase (Aox), an enzyme of fatty acid β-oxidation, from the matrix to the membrane. The binding of Aox to Pex16p, a membrane-associated peroxin required for peroxisome biogenesis, initiates the biosynthesis of phosphatidic acid and diacylglycerol (DAG) in the membrane. The formation of these two lipids and the subsequent transbilayer movement of DAG initiate the assembly of a complex between the peroxins Pex10p and Pex19p, the dynamin-like GTPase Vps1p, and several actin cytoskeletal proteins on the peroxisomal surface. This protein team promotes membrane fission, thereby executing the terminal step of peroxisome division
Electrophilic Organoiridiunn(III) Pincer Complexes on Sulfated Zirconia for Hydrocarbon Activation and Functionalization
Single-site supported organometallic catalysts bring together the favorable aspects of homogeneous and heterogeneous catalysis while offering opportunities to investigate the impact of metal–support interactions on reactivity. We report a (dmPhebox)Ir(III) (dmPhebox = 2,6-bis(4,4-dimethyloxazolinyl)-3,5-dimethylphenyl) complex chemisorbed on sulfated zirconia, the molecular precursor for which was previously applied to hydrocarbon functionalization. Spectroscopic methods such as diffuse reflectance infrared Fourier transformation spectroscopy (DRIFTS), dynamic nuclear polarization (DNP)-enhanced solid-state nuclear magnetic resonance (SSNMR) spectroscopy, and X-ray absorption spectroscopy (XAS) were used to characterize the supported species. Tetrabutylammonium acetate was found to remove the organometallic species from the surface, enabling solution-phase analytical techniques in conjunction with traditional surface methods. Cationic character was imparted to the iridium center by its grafting onto sulfated zirconia, imbuing high levels of activity in electrophilic C–H bond functionalization reactions such as the stoichiometric dehydrogenation of alkanes, with density functional theory (DFT) calculations showing a lower barrier for β-H elimination. Catalytic hydrogenation of olefins was also facilitated by the sulfated zirconia-supported (dmPhebox)Ir(III) complex, while the homologous complex on silica was inactive under comparable conditions
Mechanism of Direct Molecular Oxygen Insertion in a Palladium(II)−Hydride Bond
The mechanism of the direct insertion of molecular oxygen into a palladium hydride bond has been elucidated using quantum mechanics (B3LYP/LACVP^(**) with the PBF continuum solvent model). The key step is found to be the abstraction of the hydrogen atom resulting in the formation of a Pd^I/HO_2 (triplet) radical pair, which then proceeds to form a singlet palladium hydroperoxo species. Potential palladium(0) pathways were explored and were found to be inaccessible. The results are in agreement with recent experimental results and are consistent with our previously predicted mechanism for an analogue system
International Veterinary Epilepsy Task Force recommendations for a veterinary epilepsy-specific MRI protocol
Epilepsy is one of the most common chronic neurological diseases in veterinary practice. Magnetic resonance imaging (MRI) is regarded as an important diagnostic test to reach the diagnosis of idiopathic epilepsy. However, given that the diagnosis requires the exclusion of other differentials for seizures, the parameters for MRI examination should allow the detection of subtle lesions which may not be obvious with existing techniques. In addition, there are several differentials for idiopathic epilepsy in humans, for example some focal cortical dysplasias, which may only apparent with special sequences, imaging planes and/or particular techniques used in performing the MRI scan. As a result, there is a need to standardize MRI examination in veterinary patients with techniques that reliably diagnose subtle lesions, identify post-seizure changes, and which will allow for future identification of underlying causes of seizures not yet apparent in the veterinary literature.
There is a need for a standardized veterinary epilepsy-specific MRI protocol which will facilitate more detailed examination of areas susceptible to generating and perpetuating seizures, is cost efficient, simple to perform and can be adapted for both low and high field scanners. Standardisation of imaging will improve clinical communication and uniformity of case definition between research studies. A 6–7 sequence epilepsy-specific MRI protocol for veterinary patients is proposed and further advanced MR and functional imaging is reviewed
Psychological distress during pregnancy in a multi-ethnic community: findings from the born in Bradford cohort study
Purpose: Antenatal anxiety and depression are predictive of future mental distress, which has negative effects on children. Ethnic minority women are more likely to have a lower socio-economic status (SES) but it is unclear whether SES is an independent risk factor for mental health in pregnancy. We described the association between maternal mental distress and socio-demographic factors in a multi-ethnic cohort located in an economically deprived city in the UK. Methods: We defined eight distinct ethno-language groups (total N = 8,454) and classified a threshold of distress as the 75th centile of within-group GHQ-28 scores, which we used as the outcome for univariate and multivariate logistic regression for each ethnic group and for the sample overall. Results: Financial concerns were strongly and independently associated with worse mental health for six out of the eight ethnic groups, and for the cohort overall. In some groups, factors such as working status, education and family structure were associated with worse mental health, but for others these factors were of little importance. Conclusions: The diversity between and within ethnic groups in this sample underlines the need to take into consideration individual social, migration and economic circumstances and their potential effect on mental health in ethnically diverse areas
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