Adhesion of endothelial cells and adsorption of serum proteins on gas plasma-treated polytetrafluoroethylene

From in vitro experiments it is known that human endothelial cells show poor adhesion to hydrophobic polymers. The hydrophobicity of vascular prostheses manufactured from Teflon® or Dacron® may be the reason why endothelialization of these grafts does not occur after implantation in humans. We modified films of polytetrafluoroethylene (Teflon®) by nitrogen plasma and oxygen plasma treatments to make the surfaces more hydrophilic. Depending on the plasma exposure time, modified polytetrafluoroethylene surfaces showed water-contact angles of 15–58°, versus 96° for unmodified polytetrafluoroethylene. ESCA measurements revealed incorporation of both nitrogen- and oxygen-containing groups into the polytetrafluoroethylene surfaces, dependent on the plasma composition and exposure time. The thickness of the modified surface layer was ~1 nm. The adhesion of cultured human endothelial cells from 20% human serum-containing culture medium to modified polytetrafluoroethylene surfaces with contact angles of 20–45° led to the formation of a monolayer of cells, which was similar to the one formed on tissue culture polystyrene, the reference surface. This was not the case when endothelial cells were seeded upon unmodified polytetrafluoroethylene. Surface-modified expanded polytetrafluoroethylene prosthesis material (GORE TEX® soft tissue) also showed adhesion of endothelial cells comparable to cell adhesion to the reference surface. The amounts of serum proteins, including fibronectin, adsorbed from serumcontaining medium to modified polytetrafluoroethylene surfaces were larger than those adsorbed to unmodified polytetrafluoroethylene. Moreover, the modified surfaces probably allow the exchange of adsorbed serum proteins with cellular fibronectin

Orbital and spin physics in LiNiO2 and NaNiO2

We derive a spin-orbital Hamiltonian for a triangular lattice of e_g orbital degenerate (Ni^{3+}) transition metal ions interacting via 90 degree superexchange involving (O^{2-}) anions, taking into account the on-site Coulomb interactions on both the anions and the transition metal ions. The derived interactions in the spin-orbital model are strongly frustrated, with the strongest orbital interactions selecting different orbitals for pairs of Ni ions along the three different lattice directions. In the orbital ordered phase, favoured in mean field theory, the spin-orbital interaction can play an important role by breaking the U(1) symmetry generated by the much stronger orbital interaction and restoring the threefold symmetry of the lattice. As a result the effective magnetic exchange is non-uniform and includes both ferromagnetic and antiferromagnetic spin interactions. Since ferromagnetic interactions still dominate, this offers yet insufficient explanation for the absence of magnetic order and the low-temperature behaviour of the magnetic susceptibility of stoichiometric LiNiO_2. The scenario proposed to explain the observed difference in the physical properties of LiNiO_2 and NaNiO_2 includes small covalency of Ni-O-Li-O-Ni bonds inducing weaker interplane superexchange in LiNiO_2, insufficient to stabilize orbital long-range order in the presence of stronger intraplane competition between superexchange and Jahn-Teller coupling.Comment: 33 pages, 12 postscript figures, uses iopams.sty . This article features in New Journal of Physics as part of a Focus Issue on Orbital Physics - all contributions may be freely accessed at (http://stacks.iop.org/1367-2630/6/i=1/a=E05). The published version of this article may be found at http://stacks.iop.org/1367-2630/7/12

Perinatal or neonatal mortality among women who intend at the onset of labour to give birth at home compared to women of low obstetrical risk who intend to give birth in hospital: A systematic review and meta-analyses

Background: More women are choosing to birth at home in well-resourced countries. Concerns persist that out-of-hospital birth contributes to higher perinatal and neonatal mortality. This systematic review and meta-analyses determines if risk of fetal or neonatal loss differs among low-risk women who begin labour intending to give birth at home compared to low-risk women intending to give birth in hospital. Methods: In April 2018 we searched five databases from 1990 onward and used R to obtain pooled estimates of effect. We stratified by study design, study settings and parity. The primary outcome is any perinatal or neonatal death after the onset of labour. The study protocol is peer-reviewed, published and registered (PROSPERO No.CRD42013004046). Findings: We identified 14 studies eligible for meta-analysis including ~ 500,000 intended home births. Among nulliparous women intending a home birth in settings where midwives attending home birth are well-integrated in health services, the odds ratio (OR) of perinatal or neonatal mortality compared to those intending hospital birth was 1.07 (95% Confidence Interval [CI], 0.70 to 1.65); and in less integrated settings 3.17 (95% CI, 0.73 to 13.76). Among multiparous women intending a home birth in well-integrated settings, the estimated OR compared to those intending a hospital birth was 1.08 (95% CI, 0.84 to 1.38); and in less integrated settings was 1.58 (95% CI, 0.50 to 5.03). Interpretation: The risk of perinatal or neonatal mortality was not different when birth was intended at home or in hospital. Funding: Partial funding: Association of Ontario Midwives open peer reviewed grant. Research in Context: Evidence before this study Although there is increasing acceptance for intended home birth as a choice for birthing women, controversy about its safety persists. The varying responses of obstetrical societies to intended home birth provide evidence of contrasting views. A Cochrane review of randomised controlled trials addressing this topic included one small trial and noted that in the absence of adequately sized randomised controlled trials on the topic of intended home compared to intended hospital birth, a peer reviewed protocol be published to guide a systematic review and meta-analysis including observational studies. Reviews to date have been limited by design or methodological issues and none has used a protocol published a priori.Added value of this study Individual studies are underpowered to detect small but potentially important differences in rare outcomes. This study uses a published peer-reviewed protocol and is the largest and most comprehensive meta-analysis comparing outcomes of intended home and hospital birth. We take study design, parity and jurisdictional support for home birth into account. Our study provides much needed information to policy makers, care providers and women and families when planning for birth.Implications of all the available evidence Women who are low risk and who intend to give birth at home do not appear to have a different risk of fetal or neonatal loss compared to a population of similarly low risk women intending to give birth in hospital

Effect of Animal and Industrial Trans Fatty Acids on HDL and LDL Cholesterol Levels in Humans – A Quantitative Review

Background: Trans fatty acids are produced either by industrial hydrogenation or by biohydrogenation in the rumens of cows and sheep. Industrial trans fatty acids lower HDL cholesterol, raise LDL cholesterol, and increase the risk of coronary heart disease. The effects of conjugated linoleic acid and trans fatty acids from ruminant animals are less clear. We reviewed the literature, estimated the effects trans fatty acids from ruminant sources and of conjugated trans linoleic acid (CLA) on blood lipoproteins, and compared these with industrial trans fatty acids. Methodology/Principal Findings: We searched Medline and scanned reference lists for intervention trials that reported effects of industrial trans fatty acids, ruminant trans fatty acids or conjugated linoleic acid on LDL and HDL cholesterol in humans. The 39 studies that met our criteria provided results of 29 treatments with industrial trans fatty acids, 6 with ruminant trans fatty acids and 17 with CLA. Control treatments differed between studies; to enable comparison between studies we recalculated for each study what the effect of trans fatty acids on lipoprotein would be if they isocalorically replaced cis mono unsaturated fatty acids. In linear regression analysis the plasma LDL to HDL cholesterol ratio increased by 0.055 (95% CI 0.044-0.066) for each % of dietary energy from industrial trans fatty acids replacing cis monounsaturated fatty acids The increase in the LDL to HDL ratio for each % of energy was 0.038 (95% CI 0.012-0.065) for ruminant trans fatty acids, and 0.043 (95% CI 0.012-0.074) for conjugated linoleic acid (p = 0.99 for difference between CLA and industrial trans fatty acids; p = 0.37 for ruminant versus industrial trans fatty acids). Conclusions/Significance: Published data suggest that all fatty acids with a double bond in the trans configuration raise the ratio of plasma LDL to HDL cholesterol

Online treatment of persistent complex bereavement disorder, posttraumatic stress disorder, and depression symptoms in people who lost loved ones during the COVID-19 pandemic:study protocol for a randomized controlled trial and a controlled trial

Background: Losing a loved one during the COVID-19 pandemic is a potentially traumatic loss that may result in symptoms of persistent complex bereavement disorder (PCBD), posttraumatic stress disorder (PTSD), and depression. To date, grief-specific cognitive-behavioural therapy (CBT) has mostly been delivered through individual face-to-face formats, while studies have shown that online treatment also yields promising results. Offering treatment online is now more than ever relevant during the pan demic and may offer important benefits compared with face-to-face CBT, such as lower costs and higher accessibility. Our expectation is that grief-specific online CBT is effective in reducing PCBD, PTSD, and depression symptoms. Objective: Our aim is to evaluate the short-term and long-term effectiveness of grief-specific online CBT in reducing PCBD, PTSD, and depression symptom-levels for adults who lost a loved one during the COVID-19 pandemic. Method: This study consists of two parts. In part 1, a two-armed (unguided online CBT versus waitlist controls) randomized controlled trial will be conducted. In part 2, a two-armed (guided online CBT versus unguided online CBT) controlled trial will be conducted. Symptoms of PCBD, PTSD, and depression will be assessed via telephone interviews at pre-treatment/pre-waiting period, post-treatment/post-waiting period, and six months post-treatment. Potential participants are people who lost a loved one at least three months earlier during the COVID-19 pandemic with clinically relevant levels of PCBD, PTSD, and/or depression. Analysis of covariance and multilevel modelling will be performed. Discussion: This is one of the first studies examining the effectiveness of online grief-specific CBT. More research is needed before implementing online grief-specific CBT into clinical practice

Coupling of longitudinal and transverse motion of accelerated electrons in laser wakefield acceleration

Abstract The acceleration dynamics of electrons in a laser wakefield accelerator is discussed, in particular the coupling of longitudinal and transverse motion. This coupling effect is important for electrons injected with a velocity below the laser pulse group velocity. It is found that the electron bunch is adiabatically focused during the acceleration and that a finite bunch width contributes to bunch lengthening and growth of energy spread. These results indicate the importance of a small emittance for the injected electron bunch

Widely distributed breeding populations of Canada warbler (Cardellina canadensis) converge on migration through Central America

Background To effectively conserve migratory species, the entire range encompassed by their annual life cycle needs to be considered. Most research on Nearctic-Neotropical migratory birds has focused on the breeding grounds resulting in a general lack of knowledge regarding the wintering and migratory periods. The Canada Warbler (Cardellina canadensis) has declined by 71% from 1970 to 2012, at a rate of 2.9% per year, and is listed as Threatened in Canada. As with most Nearctic-Neotropical migrants, conservation efforts outside the breeding range are limited by a poor understanding of migration routes and the connectivity between specific breeding and wintering populations. Results To determine migratory routes of multiple breeding populations of Canada Warblers, we directly-tracked individuals using light-level geolocators deployed at four sites across the breeding range, spanning approximately 43 degrees in longitude (Alberta, Manitoba and Québec, Canada, and New Hampshire, USA). Twenty-five geolocators with usable data were recovered from three sites and were analyzed using FlightR to determine fall migration routes (n = 18) and individual wintering sites (n = 25). Individuals from all breeding populations took a western fall migration route at the Gulf of Mexico; with 77.8% of birds funnelling into a narrow geographic space along the western side of the Gulf of Mexico (97°W-99°W). We found no evidence for population-specific, parallel migration routes. Most individuals (72%) overwintered in Colombia. The remaining individuals overwintered in Venezuela. Conclusions Our results demonstrate convergence of migratory routes around a migration barrier for individuals originating from widely distributed breeding areas. Further, we suggest the potential importance of habitat around the Gulf of Mexico during migration and Andean forest in Colombia as overwintering habitat for this threatened species. Future research should be directed at understanding how these areas are used by Canada Warblers

Teaching introductory undergraduate Physics using commercial video games

Commercial video games are increasingly using sophisticated physics simulations to create a more immersive experience for players. This also makes them a powerful tool for engaging students in learning physics. We provide some examples to show how commercial off-the-shelf games can be used to teach specific topics in introductory undergraduate physics. The examples are selected from a course taught predominantly through the medium of commercial video games.Comment: Accepted to Physics Education, Fig1 does not render properly in this versio

Ethnic differences in stillbirth and early neonatal mortality in The Netherlands

Background: Ethnic disparities in perinatal mortality are well known. This study aimed to explore the contribution of demographic, socioeconomic, health behavioural and pre-existent medical risk factors among different ethnic groups on fetal and early neonatal mortality. Methods: We assessed perinatal mortality from 24.0 weeks' gestation onwards in 554 234 singleton pregnancies of nulliparous women in the linked Netherlands Perinatal Registry over the period 2000–2006. Logistic regression modelling was used. Results: Considerable ethnic differences in perinatal mortality exist especially in fetal mortality. Maternal age, socioeconomic status and pre-existent diseases could not explain these ethnic differences. Late booking visit could explain some differences. Compared with the Dutch, African women had an increased fetal mortality risk of OR 1.7 (95% CI 1.4 to 2.1); South Asian women, 1.8 (1.4 to 2.3); other non-Western women, 1.3 (1.1 to 1.6) and Turkish/Moroccan women, 1.3 (1.1 to 1.4). The risk on early neonatal mortality was only increased in other non-Western women, OR 1.3 (1.0 to 1.8). Ethnic differences were even present in the women without risk factors including preterm births. Mortality risk for East Asian and other Western women was lower or comparable with the Dutch. Conclusion: Important ethnic differences in fetal mortality exist, especially among women of African and South Asian origin. Ethnic minorities should be more acquainted with the significance of early start of prenatal care. Tailored prenatal care for women with African and South Asian origin seems necessary. More research on underlying cause of deaths is needed by ethnic group.A C J Ravelli, M Tromp, M Eskes, J C Droog, J A M van der Post, K J Jager, B W Mol, J B Reitsm