Influence of ceramide on lipid domain stability studied with small-angle neutron scattering: The role of acyl chain length and unsaturation

Ceramides and diacylglycerols are groups of lipids capable of nucleating and stabilizing ordered lipid domains, structures that have been implicated in a range of biological processes. Previous studies have used fluorescence reporter molecules to explore the influence of ceramide acyl chain structure on sphingolipid-rich ordered phases. Here, we use small-angle neutron scattering (SANS) to examine the ability of ceramides and diacylglycerols to promote lipid domain formation in the well-characterized domain- forming mixture DPPC/DOPC/cholesterol. SANS is a powerful, probe-free technique for interrogating membrane heterogeneity, as it is differentially sensitive to hydrogen\u27s stable isotopes protium and deuterium. Specifcally, neutron contrast is generated through selective deuteration of lipid species, thus enabling the detection of nanoscopic domains enriched in deuterated saturated lipids dispersed in a matrix of protiated un- saturated lipids. Using large unilamellar vesicles, we found that upon replacing 10 mol % DPPC with either C16:0 or C18:0 ceramide, or 16:0 diacylglycerol (dag), lipid domains persisted to higher temperatures. However, when DPPC was replaced with short chain (C6:0 or C12:0) or very long chain (C24:0) ceramides, or ceramides with unsaturated acyl chains of any length (C6:1(3), C6:1(5), C18:1, and C24:1), as well as C18:1-dag, lipid domains were destabilized, melting at lower temperatures than those in the DPPC/DOPC/cholesterol system. These results show how ceramide acyl chain length and unsaturation influence lipid domains, and have implications for how cell membranes might modify their function through the generation of different ceramide species

2020 Proceedings of the 3rd International Conference on Trauma Surgery Technology in Giessen

The 3 rd event of the Giessen International Conference on Trauma Surgery Technology on October, the 17th 2020 was hosted on Zoom in accordance with the worldwide corona situation. Dr Mieczakowski, Dr Yu, and Wolfram drafted in 2018 from Jan’s apartment in Bremen the manuscript which was submitted to and approved for funding by the Deutsche Forschungsgemeinschaft (DFG). At that time, we had no idea what substantial changes the conferencing concept would require. This is why we would like to thank again Michele. She first planned this year’s event after the 2019 date and then in the spring of 2020 had to replan for the new situation

Evidence of Long Range Transport of a Dark Morph Swal­lowtail Butterfly \u3ci\u3e(Papilio Glaucus)\u3c/i\u3e on a Storm Front Into Northern Michigan (Lepidoptera: Papilionidae)

A dark morph female Papilio glaucus was captured in the middle of a P. canadensis population in the center of Dickinson County, in Michigan\u27s Upper Peninsula. We are unaware of any dark female ever being captured at this latitude, and none within 400 km has ever before been reported. Morphological wing traits all score this dark female as P. glaucus, with all 31 of the other (yellow) females captured from the same group of nectar sources scoring as P. canadensis. Two diagnostic electrophoretic allozymes (PGD and LDH) show all 24 males to have 100% P. canadensis alleles, and 98% canadensis alleles were seen for the HK locus. The dark female had the P. glaucus X-linked allele for PGD, the P. canadensis X-linked allele for LDH, and was heterozygous for diagnostic HK alleles which are autosomaL All other yellow females that were examined were pure canadensis type for the sex-linked PGD and LDH alleles. One yellow female was heterozygous for the autosomal HK diagnostic alleles. A long distance blow-in on a strong weather front from the southwest is suspected as the most likely explanation for the appearance of this dark morph female of mixed (introgressed) genetic background so far from its nearest known source. The blow-in was not likely to have been in a previous year since this dark morph female would require both (1) a dark morph mother with the Y-linked dark gene and (2) a father that was part P. glaucus (i.e. without the color suppressor genes and with a PGD-100 allele), None of the males from this area had PGD or LDH alleles of the canadensis type this year or ever previously, making it unlikely that the blow-in occurred in a previous year

Evidence of Long Range Transport of a Dark Morph Swal­lowtail Butterfly \u3ci\u3e(Papilio Glaucus)\u3c/i\u3e on a Storm Front Into Northern Michigan (Lepidoptera: Papilionidae)

A dark morph female Papilio glaucus was captured in the middle of a P. canadensis population in the center of Dickinson County, in Michigan\u27s Upper Peninsula. We are unaware of any dark female ever being captured at this latitude, and none within 400 km has ever before been reported. Morphological wing traits all score this dark female as P. glaucus, with all 31 of the other (yellow) females captured from the same group of nectar sources scoring as P. canadensis. Two diagnostic electrophoretic allozymes (PGD and LDH) show all 24 males to have 100% P. canadensis alleles, and 98% canadensis alleles were seen for the HK locus. The dark female had the P. glaucus X-linked allele for PGD, the P. canadensis X-linked allele for LDH, and was heterozygous for diagnostic HK alleles which are autosomaL All other yellow females that were examined were pure canadensis type for the sex-linked PGD and LDH alleles. One yellow female was heterozygous for the autosomal HK diagnostic alleles. A long distance blow-in on a strong weather front from the southwest is suspected as the most likely explanation for the appearance of this dark morph female of mixed (introgressed) genetic background so far from its nearest known source. The blow-in was not likely to have been in a previous year since this dark morph female would require both (1) a dark morph mother with the Y-linked dark gene and (2) a father that was part P. glaucus (i.e. without the color suppressor genes and with a PGD-100 allele), None of the males from this area had PGD or LDH alleles of the canadensis type this year or ever previously, making it unlikely that the blow-in occurred in a previous year

Magma extraction pressures and the architecture of volcanic plumbing systems

The deposits of large volcanic eruptions provide the sole record of the architecture of magmatic plumbing systems in the moments when large pools of crystal-poor, eruptible magma are present in the crust. It is widely accepted that silicic magmas form by segregation of melt-rich, crystal-poor magma from a crystal-rich source; however, the depths at which segregation takes place and the distribution of the magma within the crust are not well constrained. We present a new approach to calculate pressures at which crystal-poor, eruptible magma is extracted from a crystal-rich source (i.e. mush). We apply the approach to a sequence of large (\u3e50 km3) eruptions from the Taupo Volcanic Zone (TVZ), New Zealand, which were part of a volcanic flare-up. We compare the calculated extraction pressures with pre-eruptive storage pressures for the same units. Our results show that storage and extraction pressures do not always coincide. Instead, eruptible magma can be completely segregated from the crystal-rich source, and stored at shallower levels in the crust prior to eruption. In the case of the TVZ flare-up, repeated input of material and heat – probably coupled with tectonic extension – gradually conditioned the crust and allowed extraction of eruptible magma over a growing range of pressures with time. Our approach has the potential to reveal important information on the structure and distribution of magmatic systems within the shallow crust

Homelessness among a cohort of women in street-based sex work: the need for safer environment interventions

Background: Drawing on data from a community-based prospective cohort study in Vancouver, Canada, we examined the prevalence and individual, interpersonal and work environment correlates of homelessness among 252 women in street-based sex work. Methods Bivariate and multivariate logistic regression using generalized estimating equations (GEE) was used to examine the individual, interpersonal and work environment factors that were associated with homelessness among street-based sex workers. Results Among 252 women, 43.3% reported homelessness over an 18-month follow-up period. In the multivariable GEE logistic regression analysis, younger age (adjusted odds ratio [aOR] = 0.93; 95%confidence interval [95%CI] 0.93-0.98), sexual violence by non-commercial partners (aOR = 2.14; 95%CI 1.06-4.34), servicing a higher number of clients (10+ per week vs < 10) (aOR = 1.68; 95%CI 1.05-2.69), intensive, daily crack use (aOR = 1.65; 95%CI 1.11-2.45), and servicing clients in public spaces (aOR = 1.52; CI 1.00-2.31) were independently associated with sleeping on the street. Conclusions These findings indicate a critical need for safer environment interventions that mitigate the social and physical risks faced by homeless FSWs and increase access to safe, secure housing for women.Medicine, Department ofPopulation and Public Health (SPPH), School ofNon UBCMedicine, Faculty ofReviewedFacult

The street cost of drugs and drug use patterns : relationships with sex work income in an urban Canadian setting.

BACKGROUND: This study investigated the relationship between drug use and sex work patterns and sex work income earned among street-based female sex workers (FSWs) in Vancouver, Canada. METHODS: We used data from a sample of 129 FSWs who used drugs in a prospective cohort (2007-2008), for a total of 210 observations. Bivariate and multivariable linear regression using generalized estimating equations was used to model the relationship between explanatory factors and sex work income. Sex work income was log-transformed to account for skewed data. RESULTS: The median age of the sample at first visit was 37 years (interquartile range[IQR]: 30-43), with 46.5% identifying as Caucasian, 48.1% as Aboriginal and 5.4% as another visible minority. The median weekly sex work income and amount spent on drugs was $300 (IQR=$100-$560) and$400 (IQR=$150-$780), respectively. In multivariable analysis, for a 10% increase in money spent on drugs, sex work income increased by 1.9% (coeff: 0.20, 95% CIs: 0.04-0.36). FSWs who injected heroin, FSWs with higher numbers of clients and youth compared to older women (<25 versus 25+ years) also had significantly higher sex work income. CONCLUSIONS: This study highlights the important role that drug use plays in contributing to increased dependency on sex work for income among street-based FSWs in an urban Canadian setting, including a positive dose-response relationship between money spent on drugs and sex work income. These findings indicate a crucial need to scale up access and availability of evidence-based harm reduction and treatment approaches, including policy reforms, improved social support and economic choice for vulnerable women.Medicine, Faculty ofOther UBCNon UBCMedicine, Department ofPopulation and Public Health (SPPH), School ofReviewedFacultyGraduat