1,574 research outputs found

    A vibrational circular dichroism implementation within a Slater-type-orbital based density functional framework and its application to hexa- and hepta-helicenes

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    We describe the implementation of the rotational strengths for vibrational circular dichroism (VCD) in the Slater-type orbital based Amsterdam Density Functional (ADF) package. We show that our implementation, which makes use of analytical derivative techniques and London atomic orbitals, yields origin independent rotational strengths. The basis set dependence in the particular case of Slater-type basis functions is also discussed. It turns out that the triple zeta STO basis sets with one set of polarization functions (TZP) are adequate for VCD calculations. The origin- dependence of the atomic axial tensors is checked by a distributed origin gauge implementation. The distributed and common origin gauge implementations yield virtually identical atomic axial tensors with the Slater-type basis sets employed here, proving that our implementation yields origin independent rotational strengths. We verify the implementation for a set of benchmark molecules, for which the dependence of the VCD spectra on the particular choice of the exchange–correlation functional is studied. The pure functionals BP86 and OLYP show a particularly good performance. Then, we apply this approach to study the VCD spectra of hexa- and hepta- helicenes. In particular we focus on relationships between the sign of the rotational strengths of the two helicenes

    Stent Design, Restenosis and Recurrent Stroke After Carotid Artery Stenting in the International Carotid Stenting Study

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    BACKGROUND AND PURPOSE: Open-cell carotid artery stents are associated with a higher peri-procedural stroke risk than closed-cell stents. However, the effect of stent design on long-term durability of carotid artery stenting (CAS) is unknown. We compared the medium- to long-term risk of restenosis and ipsilateral stroke between patients treated with open-cell stents versus closed-cell stents in the ICSS (International Carotid Stenting Study). METHODS: Patients with symptomatic carotid stenosis were randomized to CAS or endarterectomy and followed with duplex ultrasound for a median of 4.0 years. We analyzed data from patients with completed CAS procedures, known stent design, and available ultrasound follow-up. The primary outcome, moderate or higher restenosis (≥50%) was defined as a peak systolic velocity of >1.3 m/s on ultrasound or occlusion of the treated internal carotid artery and analyzed with interval-censored models. RESULTS: Eight hundred fifty-five patients were allocated to CAS. Seven hundred fourteen patients with completed CAS and known stent design were included in the current analysis. Of these, 352 were treated with open-cell and 362 with closed-cell stents. Moderate or higher restenosis occurred significantly less frequently in patients treated with open-cell (n=113) than closed-cell stents (n=154; 5-year risks were 35.5% versus 46.0%; unadjusted hazard ratio, 0.68; 95% CI, 0.53–0.88). There was no significant difference in the risk of severe restenosis (≥70%) after open-cell stenting (n=27) versus closed-cell stenting (n=43; 5-year risks, 8.6% versus 12.7%; unadjusted hazard ratio, 0.63; 95% CI, 0.37–1.05). The risk of ipsilateral stroke beyond 30 days after treatment was similar with open-cell and closed-cell stents (hazard ratio, 0.78; 95% CI, 0.35–1.75). CONCLUSIONS: Moderate or higher restenosis after CAS occurred less frequently in patients treated with open-cell stents than closed-cell stents. However, both stent designs were equally effective at preventing recurrent stroke during follow-up. CLINICAL TRIAL REGISTRATION: URL: http://www.isrctn.com/. Unique identifier: ISRCTN25337470

    Announcing the Minderoo - Monaco Commission on Plastics and Human Health.

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    © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Landrigan, P., Raps, H., Symeonides, C., Chiles, T., Cropper, M., Enck, J., Hahn, M., Hixson, R., Kumar, P., Mustapha, A., Park, Y., Spring, M., Stegeman, J., Thompson, R., Wang, Z., Wolff, M., Yousuf, A., & Dunlop, S. Announcing the Minderoo – Monaco Commission on Plastics and Human Health. Annals of Global Health, 88(1), (2022): 73, https://doi.org/10.5334/aogh.3916.Plastic is the signature material of our age. In the 75 years since large-scale production began in the aftermath of World War II, plastic has transformed our world, supported many of the most significant advances of modern civilization, and enabled breakthroughs in virtually every field of human endeavor. But plastic also poses great and growing dangers to human health and the environment, harms that fall disproportionately on the world’s poorest and most vulnerable populations. The extent and magnitude of these dangers are only beginning to be understood.The funding is from the Minderoo Foundation, the Centre Scientifique de Monaco, and the Prince Albert II of Monaco Foundation

    Mother Knows Best: Dominant Females Determine Offspring Dispersal in Red Foxes (Vulpes vulpes)

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    Background: Relatedness between group members is central to understanding the causes of animal dispersal. In many group-living mammals this can be complicated as extra-pair copulations result in offspring having varying levels of relatedness to the dominant animals, leading to a potential conflict between male and female dominants over offspring dispersal strategies. To avoid resource competition and inbreeding, dominant males might be expected to evict unrelated males and related females, whereas the reverse strategy would be expected for dominant females. Methodology/Principal Findings: We used microsatellites and long-term data from an urban fox (Vulpes vulpes) population to compare dispersal strategies between offspring with intra- and extra-group fathers and mothers of differing social status in red foxes. Relatedness to the dominant male had no effect on dispersal in offspring of either sex, whereas there was a strong effect of relatedness to resident females on offspring dispersal independent of population density. Males with dominant mothers dispersed significantly more often than males with subordinate mothers, whereas dispersing females were significantly more likely to have subordinate mothers compared to philopatric females. Conclusions/Significance: This is the first study to demonstrate that relatedness to resident females is important in juvenile dispersal in group-living mammals. Male dispersal may be driven by inbreeding avoidance, whereas female dispersal appears to be influenced by the fitness advantages associated with residing with the same-sex dominant parent. Selection pressure for paternal influence on offspring dispersal is low due to the limited costs associated with retaining unrelated males and the need for alternative inbreeding avoidance mechanisms between the dominant male and his female offspring. These findings have important implications for the evolution of dispersal and group living in social mammals, and our understanding of a key biological process.peerReviewe

    At what times during infection is SARS-CoV-2 detectable and no longer detectable using RT-PCR-based tests? A systematic review of individual participant data

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    Background: Tests for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral ribonucleic acid (RNA) using reverse transcription polymerase chain reaction (RT-PCR) are pivotal to detecting current coronavirus disease (COVID-19) and duration of detectable virus indicating potential for infectivity. / Methods: We conducted an individual participant data (IPD) systematic review of longitudinal studies of RT-PCR test results in symptomatic SARS-CoV-2. We searched PubMed, LitCOVID, medRxiv, and COVID-19 Living Evidence databases. We assessed risk of bias using a QUADAS-2 adaptation. Outcomes were the percentage of positive test results by time and the duration of detectable virus, by anatomical sampling sites. / Results: Of 5078 studies screened, we included 32 studies with 1023 SARS-CoV-2 infected participants and 1619 test results, from − 6 to 66 days post-symptom onset and hospitalisation. The highest percentage virus detection was from nasopharyngeal sampling between 0 and 4 days post-symptom onset at 89% (95% confidence interval (CI) 83 to 93) dropping to 54% (95% CI 47 to 61) after 10 to 14 days. On average, duration of detectable virus was longer with lower respiratory tract (LRT) sampling than upper respiratory tract (URT). Duration of faecal and respiratory tract virus detection varied greatly within individual participants. In some participants, virus was still detectable at 46 days post-symptom onset. / Conclusions: RT-PCR misses detection of people with SARS-CoV-2 infection; early sampling minimises false negative diagnoses. Beyond 10 days post-symptom onset, lower RT or faecal testing may be preferred sampling sites. The included studies are open to substantial risk of bias, so the positivity rates are probably overestimated

    Mucinous cystadenoma of the appendix misdiagnosed as cystic hydatid disease of the liver: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Primary neoplastic lesions presenting with a mucocele of the appendix are very rare and can be divided into benign variants of mucinous adenomas or cystadenomas, mucinous tumours of uncertain malignant potential or mucinous cystadenocarcinomas. Most of these tumourous mucoceles are asymptomatic and are found incidentally. The major complication of neoplastic mucinous appendiceal tumours is the development of a pseudomyxoma peritonei due to spreading of mucin-producing cells within the abdominal cavity.</p> <p>Case presentation</p> <p>A 44-year-old man presented with a history of non-specific symptoms of right upper abdominal pain. Abdominal ultrasound and computed tomography scan identified a cystic mass consistent with the morphological characteristics of an echinococcal hydatid cyst. After completing systemic albendazole therapy, an explorative laparotomy revealed a cystic tumour of the appendix. Ileocaecal resection was performed and pathology reports confirmed the diagnosis of a mucinous cystadenoma of the appendix. The postoperative course was uneventful.</p> <p>Conclusion</p> <p>Here we present the case of a man with a mucinous cystadenoma of the appendix mimicking cystic hydatid disease. We discuss the importance of re-evaluation and differential diagnostic reflections in cases of appendiceal mucocele.</p
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