60419 research outputs found
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Pan-Genomic Analysis of Clostridium botulinum Group II (Non-Proteolytic C. botulinum) Associated with Foodborne Botulism and Isolated from the Environment
No full textThe neurotoxin formed by Clostridium botulinum Group II is a major cause of foodborne botulism, a deadly intoxication. This study aims to understand the genetic diversity and spread of C. botulinum Group II strains and their neurotoxin genes. A comparative genomic study has been conducted with 208 highly diverse C. botulinum Group II strains (180 newly sequenced strains isolated from 16 countries over 80 years, 28 sequences from Genbank). Strains possessed a single type B, E, or F neurotoxin gene or were closely related strains with no neurotoxin gene. Botulinum neurotoxin subtype variants (including novel variants) with a unique amino acid sequence were identified. Core genome single-nucleotide polymorphism (SNP) analysis identified two major lineages—one with type E strains, and the second dominated by subtype B4 strains with subtype F6 strains. This study revealed novel details of population structure/diversity and established relationships between whole-genome lineage, botulinum neurotoxin subtype variant, association with foodborne botulism, epidemiology, and geographical source. Additionally, the genome sequences represent a valuable resource for the research community (e.g., understanding evolution of C. botulinum and its neurotoxin genes, dissecting key aspects of C. botulinum Group II biology). This may contribute to improved risk assessments and the prevention of foodborne botulism
Writing Artists’ Lives Across Nations and Cultures: Biography, Biofiction and Transnationality
No full textMenstrual phase-dependent differences in neurobehavioral performance: The role of temperature and the progesterone/estradiol ratio
No full textStudy objectives: Women in the luteal phase of the menstrual cycle exhibit better cognitive performance overnight than women in the follicular phase, although the mechanism is unknown. Given the link between core body temperature (CBT) and performance, one potential mechanism is the thermoregulatory role of progesterone (P4), estradiol (E2), and their ratio (P4/E2), which change across the menstrual cycle. We examined the role of P4/E2 in modulating performance during extended wake in premenopausal women. Additionally, we compared the acute effects of nighttime light exposure on performance, CBT, and hormones between the menstrual phases. Methods: Participants were studied during a 50 h constant routine and a 6.5 h monochromatic nighttime light exposure. Participants were 16 healthy, naturally cycling women (eight follicular; eight luteal). Outcome measures included reaction time, attentional failures, self-reported sleepiness, CBT, melatonin, P4, and E2. Results: As compared to women in the luteal phase, women in the follicular phase exhibited worse performance overnight. CBT was significantly associated with performance, P4, and P4/E2 but not with other sex hormones. Sex hormones were not directly related to performance. Light exposure that suppressed melatonin improved performance in the follicular phase (n = 4 per group) to levels observed during the luteal phase and increased CBT but without concomitant changes in P4/E2. Conclusions: Our results underscore the importance of considering menstrual phase when assessing cognitive performance during sleep loss in women and indicate that these changes are driven predominantly by CBT. Furthermore, this study shows that vulnerability to sleep loss during the follicular phase may be resolved by exposure to light. © 2019 Sleep Research Society 2019. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail [email protected]
Long-term exposure to PM2.5 and its constituents and risk of Non-Hodgkin lymphoma in Denmark: A population-based case–control study
No full textBackground
Particulate matter (PM) air pollution is a complex mixture and the various PM constituents likely affect health differently. The literature on the relationships among specific PM constituents and the risk of cancer is sparse. In this study, we aimed to evaluate the association of PM2.5 and its constituents with the incidence of non-Hodgkin lymphoma (NHL) and the two main NHL subtypes.
Methods
We undertook a nationwide register-based case-control study including 20,847 cases registered in the Danish Cancer Registry with NHL between 1989 and 2014. Among the entire Danish population, we selected 41,749 age and sex-matched controls randomly from the Civil Registration System. We assessed modelled outdoor PM concentrations at addresses of cases and controls with a state-of-the-art multi scale air pollution modelling system and used conditional logistic regression to estimate odds ratios (ORs) adjusted for individual and neighborhood level socio-demographic variables.
Results
The 10-year time-weighted average concentrations of PM2.5, primary carbonaceous particles (BC/OC), secondary inorganic aerosols (SIA), secondary organic aerosols (SOA) and sea salt were 17.4, 2.3, 7.8, 0.3, and 4.1 μg/m3, respectively among controls. The results showed higher risk for NHL in association with exposure to BC/OC (OR = 1.03; 95% CI: 1.00, 1.07, per interquartile range (IQR)) and SOA (OR = 1.54; 95% CI: 1.13, 2.09, per IQR). The results indicated a higher risk for follicular lymphoma in association with several PM components. Including PM2.5 (OR = 1.16; 95% CI: 0.98–1.38), BC/OC (OR = 1.05; 95% CI: 0.97–1.14), SIA (OR = 1.44; 95% CI: 0.80–1.08), SOA (OR = 4.52; 95% CI: 0.86–23.83) per IQR.
Conclusion
This is the first study on PM constituents and the risk of NHL. The results indicated an association with primary carbonaceous and secondary organic PM. The results need replication in other settings before any firm conclusion can be reached
Influence of periodontal disease on risk of dementia: a systematic literature review and a meta-analysis
No full textPeriodontal disease (PD) is common and increases cardiovascular diseases. However, it is unclear whether PD is associated with increased risk of dementia. We carried out a systematic review and meta-analysis to investigate the influence of PD on dementia. We projected the number of dementia cases to be saved by reducing PD prevalence in the world. We searched cohort and case–control studies reporting the association of PD with all dementia (or any specific type of dementia) through PubMed, MEDLINE, PsycINFO, SocINDEX, CINHAL, and CNKI until 7th November 2018. Five cohorts and seven case–control studies were identified for review. We pooled eligible data to calculate relative risk (RR) of dementia in relation to PD and computed the number of dementia cases saved through reducing PD prevalence. Of 12 studies, six were undertaken in Asia, four in Europe and two in America. Eleven studies showed a positive association between PD and the risk of dementia, of which 10 were significant, and one reported a non-significant inverse association. Overall their quality was good. Pooled RR of dementia in relation to PD from all high quality studies was 1.38 (95%CI 1.01–1.90); in the five cohorts was 1.18 (1.06–1.31) and in the two case–control studies 2.25 (1.48–3.42). A 50% reduction in the current prevalence of 20% of PD in the population could save 850,000 (630,000–1,420,000) patients with dementia in the world. PD could increase the risk of incident dementia. Preventing and treating PD could contribute to controlling the global epidemic of dementia
Solution processed perovskite incorporated tandem photovoltaics: developments, manufacturing, and challenges
No full textPhotovoltaics based on organic–inorganic as well as all inorganic semiconducting perovskites have emerged as a high performing technology at a lower cost. Intense research carried out in this regard over the last decade has resulted in single junction power conversion efficiencies that now exceed 25%. Furthermore, combining wide-bandgap perovskites with other narrow-bandgap absorbers such as silicon has enabled efficiencies exceeding 24%. Such tandem architectures provide the possibility of increasing the power conversion efficiency with either a little increase in cost or even at a lower cost. In this review, we discuss the emerging tandem concepts that incorporate perovskites in at least one sub-cell and can also be printed on roll-to-roll manufacturing lines. Initially, we discuss the progress in the field of perovskite/silicon tandem architectures followed by a discussion on perovskite/copper indium gallium selenide tandem devices. Then, recent progress in all-perovskite tandem devices is discussed. This is then followed by developments combining perovskites and organic bulk heterojunction absorbers. Subsequently, we discuss roll-to-roll and sheet-to-sheet printing techniques that can be used for scaled-up manufacturing of the above tandem architectures, which is then followed by reported work on perovskites that have utilised these printing techniques. Finally, we discuss prospects and future directions focusing on material stability and elimination of toxic solvents that are typically used in lab-scale perovskite solar cell fabrication processes and on less well investigated applications such as energy harvesting in space
THz nonlinear optics in silicon and germanium for third harmonic generation.
No full textThis thesis is concerned with the generation of terahertz (THz) light in the frequency range of 5–15 THz. This range is difficult to produce at high intensities, and no high-power table-top sources exist for it. The reasons for the interest in this frequency range are broad, and include communications, chemical and biomedical spectroscopy, etc. Different applications require highly specific technological characteristics, such as room temperature operation or very high stability, and satisfying all possible requirements in one generation mechanism is difficult. In this study, we sought to develop a solution to the problem of optical pumping of donor impurities in silicon, to control the orbit and spin of the donor electron in quantum computer gates. It is obvious that great advantages would be obtained if this control were possible with a bench-top source, and this is the key to enabling such high efficiency control to spread to the wider community of physicists and engineers working on spin qubits.
To achieve this purpose, we explore the possibility of use a cheap material like single doped silicon and germanium to triple THz radiation from 1.7 to 5 THz (which is available from Quantum Cascade Laser diodes). The presence of the dopants modifies substantially the optical properties of the semiconductors, generating large nonlinear coefficients at THz frequencies. Samples of bismuth doped silicon and phosphorus, arsenic and antimony doped germanium has been characterised using frequency-domain and time-domain spectroscopy, and finally the optical nonlinear coefficient of Si:Bi has been measure by a Four Wave Mixing (FWM) experiment. We have found that the nonlinear susceptibility of Si:Bi at resonance is the highest ever reported for a bulk material
Prioritising indoor air quality in building design can mitigate future airborne viral outbreaks
No full textThe ongoing COVID-19 pandemic has brought into focus how poor indoor air quality can amplify
the effects of airborne viruses. Rather than promoting health and wellbeing, our built
environment often worsens air quality through inadequate ventilation, air recirculation, material
specification and the additional pollution load from mechanical heating and cooling. In this thinkpiece,
we introduce a selection of interrelated building design strategies to improve indoor air
quality and reduce the spread and impact of airborne disease. We also highlight the need for
interdisciplinary collaboration, targeted policy change and leadership on air quality to build
resilience against future airborne viral outbreaks
Changes in air passenger demand as a result of the COVID-19 crisis: using Big Data to inform tourism policy
No full textThis paper develops a methodology for the early detection of reactivation of tourist markets to help mitigate the effects of the COVID-19 crisis, using Skyscanner data on air passenger searches (>5,000 million) and picks (>600 million), for flights between November 2018 and December 2020, through ForwardKeys. For future travel during the May to September 2020 period, the desire to travel (based on the number of flight searches) has dropped by about 30% in Europe and the Americas, and by about 50% in Asia, while intention to travel (the number of flight picks, the final selections amongst flight searches) has dropped a further 10-20%. Most source markets remain optimistic about air travel during the last quarter of 2020, suggesting a U shape recovery. However, optimism has dwindled as time passes, suggesting a flatline L shape. A traffic light dashboard for domestic and inbound air travel demand to Spain shows how destination managers might use Big Data relating to the early recovery of key source markets to develop targeted marketing strategies. We show how Big Data provides timely granular data essential in highly volatile situations, and we argue that destination management organisations must improve their Big Data analytical and evidence-based, decision-making skills
Euroscepticism after Brexit
No full textIt would be very easy to assume that the UK’s withdrawal from the European Union in January 2020 finally put the running sore of UK-EU relations to bed for good: after several years of rancorous debate, might not the UK move on to other issues? Buta moment’s reflection will point towards the need for having an understanding of the European issue in British politics, not just now but also for the longer-term future.
In this article, I want to try to map out the historical trajectory of euroscepticism, both as a concept in of itself and as a marker wider currents. The central argument to be made is that the existence and the persistence of a European ‘other’ to the British ‘us’ means that euroscepticism is now entering its third major era since the Second World War and will continue to have significant effects on both rhetoric and policy in the UK.</p
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