Frequencies of the T-455C and C-482T apoCIII gene polymorphisms in different South African population groups and their relationship to fasting serum triglyceride levels

Studies have demonstrated that serum triglyceride levels are higher in Indian and White than Black South African subjects. Polymorphisms in the apoCIII gene have been associated with raised triglyceride levels. This study investigated the prevalence of apoCIII polymorphisms and their effect on triglyceride levels in three South African population groups and in subjects with fasting hypertriglyceridaemia (HT). Two apoCIII polymorphic sites (T-455C and C-482T) were studied in 78 European, 24 Indian and 25 African subjects. Each ethnic group included HT and non-HT (control) patients. Although triglyceride levels were much higher in the HT subjects, no significant differences were noted between the groups for allele or genotype frequencies at either apoCIII locus. Furthermore, at neither locus was there an association between the genotype and serum triglyceride levels. The HT and control subjects were therefore combined and ethnic differences in allele frequencies were investigated. The African subjects had a higher frequency (0.79) of the unfavourable C allele at position 455 than both Indian (0.56; p‹0.05) and European (0.41; p‹0.0005) subjects. Furthermore, African subjects had a higher frequency (0.77) of the unfavourable T allele at locus 482 than Indian (0.44, p‹0.005) and European (0.36, p‹0.0005) subjects despite triglyceride levels being lower in the African (0.60 [1.60] mmol/l) than European (0.90 [0.40] mmol/l; p‹0.05) control subjects. These results suggest that the apoCIII polymorphisms studied do not contribute to the raised triglyceride levels in HT subjects and do not explain the ethnic differences observed in fasting serum triglyceride levels

Gender-specific association of the K121Q Ectonucleotide Pyrophosphatase Phosphodiesterase (ENPP) 1 polymorphism with subcutaneous adiposity in a South African Black population

Purpose: This study aimed to determine whether the ENPP-1 K121Q (rs1044498) polymorphism was associated with adiposity and cardiometabolic disease markers within a South African Black population. Methods: Black participants from the greater Johannesburg–Soweto area in South Africa, for whom metabolic syndrome status, cardiometabolic disease markers, adipokine levels and body fat distribution had already been measured, were genotyped by PCR-RFLP for the presence of the K121Q polymorphism.Results: Within a cohort of 345 Black South Africans, the frequency of the ENPP-1 K121Q C allele was 0.89. In the total cohort, the K121Q polymorphism was not significantly associated with any cardiometabolic disease markers or adipokine levels. However, in the female population the CC genotype was shown to be associated with increased abdominal subcutaneous fat levels (p=0.007). Conclusion: This cohort of Black South Africans had a higher frequency of the C allele when compared to reported data for Asian and Caucasian populations, however this frequency was comparable to other African data. The presence of the rs1044498 polymorphism was not associated with markers of cardiometabolic disease, suggesting that these associations may be population dependent. The gender-specific genotypic association with subcutaneous fat levels is a novel finding requiring further investigation

Leveraging sponsorship to achieve consumer relationship objectives through the creation of ‘marketing spaces’: An exploratory study

This paper explores the emergence of sponsorship-linked events as a strategy to leverage relational outcomes through sponsorship investment. The growing use of sponsorship-linked events reinforces the need to understand the potential of such leverage strategies, thus the findings contribute to the body of literature on effective sponsorship practices. Findings from semi-structured interviews with Sponsorship and Marketing Managers suggest a shifting orientation among sponsors towards the pursuit of relational objectives. The privileged access to consumers afforded through sponsorship allows sponsors to manufacture opportunities to create intimacy with customers through sponsorship-linked events in relaxed, comfortable environments; thus sponsorship-linked events are positioned as a rich environment to add value to consumer–brand interactions and achieve relational objectives. Hosting specifically designed events affords sponsors an increased modicum of control over consumer–brand experiences in sponsorship environments characterised by a lack of control over sponsored property actions. However, this control may be eroded by social media technologies, which facilitate consumer–consumer communication around sponsorship-linked events. Social media, however, is proposed as a useful tool to elicit consumer feedback, addressing the misalignment between current sponsorship evaluation practices and emergent relational objectives revealed in the empirical findings. Therefore, successfully activating the sponsorship-linked marketing space demands an integrated and strategic approach

Self-organization of stack-up block copolymers into polymeric supramolecules

Polyethylene oxide –b– polypropylene oxide -b- polyethylene oxide (EO106PO70EO106) block copolymer self-organizes into polymeric supramolecules, characterized by NMR as phase transition from the isotropic stack-up block structure to the ordered cubic polymeric supramolecular structure. Its dependence on both temperature and copolymer concentration is clearly shown by the changes in line shape and chemical shift of the PO70blockβ,γresonances

The VLT-FLAMES Tarantula Survey

A spectroscopic analysis has been undertaken for the B-type multiple systems (excluding those with supergiant primaries) in the VLT-FLAMES Tarantula Survey (VFTS). Projected rotational velocities, vesini, for the primaries have been estimated using a Fourier Transform technique and confirmed by fitting rotationally broadened profiles. A subset of 33 systems with vesini ≤ 80 km s-1 have been analysed using a TLUSTY grid of model atmospheres to estimate stellar parameters and surface abundances for the primaries. The effects of a potential flux contribution from an unseen secondary have also been considered. For 20 targets it was possible to reliably estimate their effective temperatures (Teff) but for the other 13 objects it was only possible to provide a constraint of 20 000 ≤ Teff ≤ 26 000 K – the other parameters estimated for these targets will be consequently less reliable. The estimated stellar properties are compared with evolutionary models and are generally consistent with their membership of 30 Doradus, while the nature of the secondaries of 3 SB2 system is discussed. A comparison with a sample of single stars with vesini ≤ 80 km s-1 obtained from the VFTS and analysed with the same techniques implies that the atmospheric parameters and nitrogen abundances of the two samples are similar. However, the binary sample may have a lack of primaries with significant nitrogen enhancements, which would be consistent with them having low rotational velocities and having effectively evolved as single stars without significant rotational mixing. This result, which may be actually a consequence of the limitations of the pathfinder investigation presented in this paper, should be considered as a motivation for spectroscopic abundance analysis of large samples of binary stars, with high quality observational data

The Tarantula massive binary monitoring: III. Atmosphere analysis of double-lined spectroscopic systems

Context. Accurate stellar parameters of individual objects in binary systems are essential to constrain the effects of binarity on stellar evolution. These parameters serve as a prerequisite to probing existing and future theoretical evolutionary models. Aims. We aim to derive the atmospheric parameters of the 31 double-lined spectroscopic binaries in the Tarantula Massive Binary Monitoring sample. This sample, composed of detached, semi-detached and contact systems with at least one of the components classified as an O-type star, is an excellent test-bed to study how binarity can impact our knowledge of the evolution of massive stars. Methods. In the present paper, 32 epochs of FLAMES/GIRAFFE spectra are analysed by using spectral disentangling to construct the individual spectra of 62 components. We then apply the CMFGEN atmosphere code to determine their stellar parameters and their helium, carbon, and nitrogen surface abundances. Results. Among the 31 systems that we study in the present paper, we identify between 48 and 77% of them as detached, likely pre-interacting systems, 16% as semi-detached systems, and between 5 and 35% as systems in or close to contact phase. Based on the properties of their components, we show that the effects of tides on chemical mixing are limited. Components on longer-period orbits show higher nitrogen enrichment at their surface than those on shorter-period orbits, in contrast to expectations of rotational or tidal mixing, implying that other mechanisms play a role in this process. For semi-detached systems, components that fill their Roche lobe are mass donors. They exhibit higher nitrogen content at their surface and rotate more slowly than their companions. By accreting new material, their companions spin faster and are likely rejuvenated. Their locations in the N − v sin i diagram tend to show that binary products are good candidates to populate the two groups of stars (slowly rotating, nitrogen-enriched objects and rapidly rotating non-enriched objects) that cannot be reproduced through single-star population synthesis. Finally, we find no peculiar surface abundances for the components in (over-)contact systems, as has been suggested by evolutionary models for tidal mixing. Conclusions. This sample, consisting of 31 massive binary systems, is the largest sample of binaries composed of at least one O-type star to be studied in such a homogeneous way by applying spectral disentangling and atmosphere modelling. The study of these objects gives us strong observational constraints to test theoretical binary evolutionary tracks

The Physics of Star Cluster Formation and Evolution

© 2020 Springer-Verlag. The final publication is available at Springer via https://doi.org/10.1007/s11214-020-00689-4.Star clusters form in dense, hierarchically collapsing gas clouds. Bulk kinetic energy is transformed to turbulence with stars forming from cores fed by filaments. In the most compact regions, stellar feedback is least effective in removing the gas and stars may form very efficiently. These are also the regions where, in high-mass clusters, ejecta from some kind of high-mass stars are effectively captured during the formation phase of some of the low mass stars and effectively channeled into the latter to form multiple populations. Star formation epochs in star clusters are generally set by gas flows that determine the abundance of gas in the cluster. We argue that there is likely only one star formation epoch after which clusters remain essentially clear of gas by cluster winds. Collisional dynamics is important in this phase leading to core collapse, expansion and eventual dispersion of every cluster. We review recent developments in the field with a focus on theoretical work.Peer reviewe

Star clusters near and far; tracing star formation across cosmic time

© 2020 Springer-Verlag. The final publication is available at Springer via https://doi.org/10.1007/s11214-020-00690-x.Star clusters are fundamental units of stellar feedback and unique tracers of their host galactic properties. In this review, we will first focus on their constituents, i.e.\ detailed insight into their stellar populations and their surrounding ionised, warm, neutral, and molecular gas. We, then, move beyond the Local Group to review star cluster populations at various evolutionary stages, and in diverse galactic environmental conditions accessible in the local Universe. At high redshift, where conditions for cluster formation and evolution are more extreme, we are only able to observe the integrated light of a handful of objects that we believe will become globular clusters. We therefore discuss how numerical and analytical methods, informed by the observed properties of cluster populations in the local Universe, are used to develop sophisticated simulations potentially capable of disentangling the genetic map of galaxy formation and assembly that is carried by globular cluster populations.Peer reviewedFinal Accepted Versio