Ethnic differences in the +405 and -460 vascular endothelial growth factor polymorphisms and peripheral neuropathy in patients with diabetes residing in a North London, community in the United Kingdom.

BACKGROUND: There are marked ethnic differences in the susceptibility to the long-term diabetic vascular complications including sensory neuropathy. The vascular endothelial growth factor (VEGF) +405 (C/G) and -460 (T/C) polymorphisms are associated with retinopathy and possibly with nephropathy, however no information is available on their relationship with peripheral neuropathy. Therefore, we examined the prevalence of these VEGF genotypes in a multi-ethnic cohort of patients with diabetes and their relationship with evident peripheral diabetic neuropathy. METHODS: In the current investigation, we studied 313 patients with diabetes mellitus of African-Caribbean, Indo-Asian and Caucasian ethnic origin residing in an inner-city community in London, United Kingdom attending a single secondary care centre. Genotyping was performed for the VEGF +405 and VEGF -460 polymorphisms using a pyrosequencing technique. RESULTS: Forty-nine patients (15.6%) had clinical evidence of peripheral neuropathy. Compared to Caucasian patients, African-Caribbean and Indo-Asian patients had lower incidence of neuropathy (24.6%, 14.28%, 6.7%, respectively; P = 0.04). The frequency of the VEGF +405 GG genotype was more common in Indo-Asian patients compared to African-Caribbean and Caucasian patients (67.5%, 45.3%, 38.4%, respectively; p ≤ 0.02). The G allele was more common in patients with type 2 diabetes of Indo-Asian origin compared to African-Caribbean and Caucasian origin (p ≤ 0.02). There was no difference between the ethnic groups in VEGF -460 genotypes. The distributions of the VEGF +405 and VEGF -460 genotypes were similar between the diabetic patients with and without neuropathy. CONCLUSIONS: In this cohort of patients, VEGF +405 and VEGF -460 polymorphisms were not associated with evident diabetic peripheral neuropathy, however an association was found between VEGF +405 genotypes and Indo-Asian which might have relevance to their lower rates of ulceration and amputation. This finding highlights the need for further investigation of any possible relationship between VEGF genotype, circulating VEGF concentrations and differential vulnerability to peripheral neuropathy amongst diabetic patients of different ethnic backgrounds

Ex-post Performance Implications of Divergence of Managers’ Perceptions of ‘Distance’ From ‘Reality’ in International Business

Despite much research on “distance”, little attention has been paid to the effect of divergence of managers’ perceptions of distance from reality (i.e. distance divergence) and its implications for firm performance. This knowledge is highly important since managerial perceptions of the firm’s environment do not always coincide with the actual environmental characteristics. Consequently, strategies based on inaccurate data may result in erroneous forecasts, missed opportunities and business failure. Using survey data from senior managers of Swedish exporters and corresponding objective data, this study is a first attempt to explore the ex-post performance implications of “distance divergence” when expanding into foreign markets. Our results demonstrate that the larger the divergence between managers’ perceptions of cultural distance and corresponding “objective” distance, the lower the performance expressed in companies’ sales. However, over/underestimation of cultural distance does not have differential effects on firm performance.“Stiftelsen Olle Hakelius Stipendiefond”, Grant no: 1165001

Hyperfine interactions and electron distribution in Fe(II)Fe(I) and Fe(I)Fe(I) models for the active site of the [FeFe] hydrogenases: Mössbauer spectroscopy studies of low-spin Fe(I)

[[abstract]]Mössbauer studies of [{μ-S(CH2C(CH3)2CH2S}(μ-CO)FeIIFeI(PMe3)2(CO)3]PF6 (1 OX ), a model complex for the oxidized state of the [FeFe] hydrogenases, and the parent FeIFeI derivative are reported. The paramagnetic 1 OX is part of a series featuring a dimethylpropanedithiolate bridge, introducing steric hindrance with profound impact on the electronic structure of the diiron complex. Well-resolved spectra of 1 OX allow determination of the magnetic hyperfine couplings for the low-spin distal FeI ( FeI D ) site, A x,y,z = [−24 (6), −12 (2), 20 (2)] MHz, and the detection of significant internal fields (approximately 2.3 T) at the low-spin ferrous site, confirmed by density functional theory (DFT) calculations. Mössbauer spectra of 1 OX show nonequivalent sites and no evidence of delocalization up to 200 K. Insight from the experimental hyperfine tensors of the FeI site is used in correlation with DFT to reveal the spatial distribution of metal orbitals. The Fe–Fe bond in [Fe2{μ-S(CH2C(CH3)2CH2S}(PMe3)2(CO)4] (1) involving two dz2 -type orbitals is crucial in keeping the structure intact in the presence of strain. On oxidation, the distal iron site is not restricted by the Fe–Fe bond, and thus the more stable isomer results from inversion of the square pyramid, rotating the dz2 orbital of FeI D . DFT calculations imply that the Mössbauer properties can be traced to this dz2 orbital. The structure of the magnetic hyperfine coupling tensor, A, of the low-spin FeI in 1 OX is discussed in the context of the known A tensors for the oxidized states of the [FeFe] hydrogenases.[[journaltype]]國外[[ispeerreviewed]]Y[[booktype]]紙本[[booktype]]電子版[[countrycodes]]DE

Magnetic Blocking in a Linear Iron(I) Complex

Single-molecule magnets that contain one spin centre may represent the smallest possible unit for spin-based computational devices. Such applications, however, require the realization of molecules with a substantial energy barrier for spin inversion, achieved through a large axial magnetic anisotropy. Recently, significant progress has been made in this regard by using lanthanide centres such as terbium(III) and dysprosium(III), whose anisotropy can lead to extremely high relaxation barriers. We contend that similar effects should be achievable with transition metals by maintaining a low coordination number to restrict the magnitude of the d-orbital ligand-field splitting energy (which tends to hinder the development of large anisotropies). Herein we report the first two-coordinate complex of iron(I), [Fe(C(SiMe3) 3)2]-, for which alternating current magnetic susceptibility measurements reveal slow magnetic relaxation below 29 K in a zero applied direct-current field. This S =complex exhibits an effective spin-reversal barrier of U eff = 226(4) cm-1, the largest yet observed for a single-molecule magnet based on a transition metal, and displays magnetic blocking below 4.5 K