414 research outputs found
Do we need delocalised wavefunctions for the excited state dynamics of 1,1-difluoroethylene?
In this work we set up a model Hamiltonian to study the excited state quantum
dynamics of 1,1-difluoroethylene, a molecule that has equivalent atoms
exchanged by a torsional symmetry operation leading to equivalent minima on the
potential energy surface. In systems with many degrees of freedom where the
minimum energy geometry is not unique, the ground state wavefunction will be
delocalised among multiple minima. In this small test system, we probe the
excited state dynamics considering localised (in a single minimum) and
delocalised (spread over among multiple minima) wavefunctions and check whether
this choice would influence the final outcome of the quantum dynamics
calculations. Our molecular Hamiltonian comprises seven electronic states,
including valence and Rydberg states, computed with the MS-CASPT2 method and
projected onto the vibrational coordinates of the twelve normal modes of
1,1-difluoroethylene in its vibrational ground state. This Hamiltonian has been
symmetrised along the torsional degree of freedom to make both minima
completely equivalent and the model is supported by the excellent agreement
with the experimental absorption spectrum. Quantum dynamics results show that
the different initial conditions studied do not appreciably affect the excited
state populations or the absorption spectrum when the dynamics is simulated
assuming a delta pulse excitation.Comment: This is a post-peer-review, pre-copyedit version of an article
accepted in the Canadian Journal of Chemistry. The final authenticated
version will be available online at their websit
Do sputum or circulating blood samples reflect the pulmonary transcriptomic differences of COPD patients? A multi-tissue transcriptomic network META-analysis
BACKGROUND: Previous studies have identified lung, sputum or blood transcriptomic biomarkers associated with the severity of airflow limitation in COPD. Yet, it is not clear whether the lung pathobiology is mirrored by these surrogate tissues. The aim of this study was to explore this question. METHODS: We used Weighted Gene Co-expression Network Analysis (WGCNA) to identify shared pathological mechanisms across four COPD gene-expression datasets: two sets of lung tissues (L1 n = 70; L2 n = 124), and one each of induced sputum (S; n = 121) and peripheral blood (B; n = 121). RESULTS: WGCNA analysis identified twenty-one gene co-expression modules in L1. A robust module preservation between the two L datasets was observed (86%), with less preservation in S (33%) and even less in B (23%). Three modules preserved across lung tissues and sputum (not blood) were associated with the severity of airflow limitation. Ontology enrichment analysis showed that these modules included genes related to mitochondrial function, ion-homeostasis, T cells and RNA processing. These findings were largely reproduced using the consensus WGCNA network approach. CONCLUSIONS: These observations indicate that major differences in lung tissue transcriptomics in patients with COPD are poorly mirrored in sputum and are unrelated to those determined in blood, suggesting that the systemic component in COPD is independently regulated. Finally, the fact that one of the preserved modules associated with FEV1 was enriched in mitochondria-related genes supports a role for mitochondrial dysfunction in the pathobiology of COPD
Associations between trace elements and cognitive decline: an exploratory 5-year follow-up study of an elderly cohort
Trace elements (TE) homeostasis is crucial in normal brain functioning. Although imbalances have the potential to exacerbate events leading neurodegenerative diseases, few studies have directly addressed the eventual relationships between TE levels in the human body and future cognitive status. The present study aimed to assess how different TE body-levels relate to cognitive decline. This exploratory research included a study-group (RES) of 20 elderly individuals living in two Portuguese geographical areas of interest (Estarreja; Mértola), as well as a 20 subjects neuropsychological control-group (CTR). Participants were neuropsychologically assessed through the Mini Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA) and the RES group was biomonitored for TE through fingernail analysis. After 5 years, the cognitive assessments were repeated. Analyses of the RES neuropsychological data showed an average decrease of 6.5 and 5.27 points in MMSE and MoCA, respectively, but TE contents in fingernails were generally within the referenced values for non-exposed individuals. Higher levels of Nickel and Selenium significantly predicted lesser cognitive decline within 5 years. Such preliminary results evidence an association between higher contents of these TE and higher cognitive scores at follow-up, suggesting their contribution to the maintenance of cognitive abilities. Future expansion of the present study is needed in order to comprehensively assess the potential benefits of these TE.This research was supported by the Portuguese Foundation for Science and Technology (Fundação para a Ciência e a Tecnologia (FCT)) — grants SFRH/BPD/71030/2010, IF/01325/2015, SFRH/BD/146680/2019, and UIDB/04035/2020. Funding for this research was also provided by the Labex DRIIHM, French programme “Investissements d’Avenir” (ANR-11-LABX-0010), which is managed by the ANR
Immunophenotyping of Circulating and Intratumoral Myeloid and T Cells in Glioblastoma Patients
Glioblastoma is the most common and lethal primary brain malignancy that almost inevitably recurs as therapy-refractory cancer. While the success of immune checkpoint blockade (ICB) revealed the immense potential of immune-targeted therapies in several types of cancers outside the central nervous system, it failed to show objective responses in glioblastoma patients as of now. The ability of glioblastoma cells to drive multiple modes of T cell dysfunction while exhibiting low-quality neoepitopes, low-mutational load, and poor antigen priming limits anti-tumor immunity and efficacy of antigen-unspecific immunotherapies such as ICB. An in-depth understanding of the GBM immune landscape is essential to delineate and reprogram such immunosuppressive circuits during disease progression. In this view, the present study aimed to characterize the peripheral and intratumoral immune compartments of 35 glioblastoma patients compared to age- and sex-matched healthy control probands, particularly focusing on exhaustion signatures on myeloid and T cell subsets. Compared to healthy control participants, different immune signatures were already found in the peripheral circulation, partially related to the steroid medication the patients received. Intratumoral CD4+ and CD8+ TEM cells (CD62Llow/CD45ROhigh) revealed a high expression of PD1, which was also increased on intratumoral, pro-tumorigenic macrophages/microglia. Histopathological analysis further identified high PSGL-1 expression levels of the latter, which has recently been linked to increased metastasis in melanoma and colon cancer via P-selectin-mediated platelet activation. Overall, the present study comprises immunophenotyping of a patient cohort to give implications for eligible immunotherapeutic targets in neurooncology in the future
Cross-Jurisdictional Analysis of Administrative Health Data and Primary Care Electronic Medical Records in Canada
Over the last 30 years, public investments have created and supported administrative health data resources and repositories in Canada to support population health, health services and health policy research. Together, these repositories represent the building blocks of a world-class data platform that enables evidence-informed clinical, managerial and policy decisions. But because Canada’s universal health care system is managed at the provincial level, these repositories have limited capacity to share and use data across jurisdictional boundaries. Challenges with timely access to data remain and differences between jurisdictions affect the quality, scope, and impact of work that could be done. There are considerable benefits to be obtained from collaboration seeking to compare and/or combine health data across jurisdictional borders, despite the limitations in sharing the data. To ensure that Canadians continue to have access to high-quality health care and benefit from effective health policies, researchers and system planners must have access to and be able to make effective use of administrative health data. The purpose of this paper is to describe how we approached and addressed challenges in data access, data governance and data architecture in a Canadian cross-jurisdictional research study
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Virtual Reality, 360⁰ Video, and Journalism Studies: Conceptual Approaches to Immersive Technologies
A growing number of newsrooms are experimenting with Virtual Reality (VR) and other immersive storytelling techniques, typically supported by technology companies that see journalism as a potential vehicle for taking VR mainstream. The resulting pieces have been wide-ranging in topic, style, and scope, but all introduce new complexities to journalistic norms and practices. To date, however, journalism studies scholars have conducted relatively little research into these immersive technologies. This essay proposes three conceptual approaches to examining VR journalism: Actor-Network Theory, normative theory, and a sociological perspective on journalistic work
Cosmopolitan Sentiment: Politics, Charity, and Global Poverty
Duties to address global poverty face a motivation gap. We have good reasons for acting yet we do not, at least consistently. A ‘sentimental education’, featuring literature and journalism detailing the lives of distant others has been suggested as a promising means by which to close this gap (Nussbaum in Upheavals of Thought: The Intelligence of Emotions, CUP, Cambridge, 2001; Rorty in Truth and Progress: Philosophical Papers, vol. 3, CUP, Cambridge, 1998). Although sympathetic to this project, I argue that it is too heavily wed to a charitable model of our duties to address global poverty—understood as requiring we sacrifice a certain portion of our income. However, political action, aimed at altering institutions at both a global and a local level is likely to be necessary in order to provide effective long-term solutions to poverty globally. To rectify this, the article develops an alternative dialogical account of sentimental education, suitable for motivating support for political action to address global poverty
Access to Health Care in Contexts of Livelihood Insecurity: A Framework for Analysis and Action
The authors present a framework for analysis and action to explore and improve access to health care in resource-poor countries, especially in Africa
Zygostates alleniana (Orchidaceae: Epidendroideae: Cymbidieae: Oncidiinae): estructura floral relacionada con la polinización
The genus Zygostates Lindl. (Orchidaceae) comprises about 20 species of small Neotropical epiphytic plants, represented in its southernmost limit by the species Z. alleniana. In this paper, we studied morphological and anatomical floral characteristics of this species related to pollination mechanism. We confirmed the presence of the unicellular trichomes on the base of the lip and side lobes secreting oil, constituting a trichomal elaiophore. The oil is deposited beneath the cuticle at the apex of the trichomes forming small blisters. The oil could represent a reward for the species Lophopedia nigrispinis, which would be a potential pollinator of Z. alleniana in a natural area within the geographic range of this plant species. Moreover, we prove that the reconfiguration of the pollinaruim is due to the dehydration of the walls cell. This reconfiguration could favor cross-pollination mechanism already described for other species of the family Orchidaceae. Finally, we discuss the floral characters present in Z. alleniana with closely related species.El género Zygostates Lindl. (Orchidaceae) comprende aproximadamente 20 especies de pequeñas plantas epífitas con distribución neotropical, representado en su límite más austral por la especie Z. alleniana. En el presente trabajo se estudian morfológica y anatómicamente las características florales de esta especie relacionadas con el mecanismo de polinización. Se confirma la presencia de tricomas unicelulares en la base del labelo y lóbulos laterales que actúan secretando aceite, constituyendo un elaióforo tricomatoso. El aceite se deposita por debajo de la cutícula en el ápice de los tricomas formando pequeñas ampollas. El aceite podría representar una recompensa para la especie Lophopedia nigrispinis, la cual sería un posible polinizador de Z. alleniana en un área natural dentro del rango de distribución geográfica de esta especie vegetal. Por otro lado, se comprueba que la reconfiguración del polinario se debe a la deshidratación de las paredes celulares. Esta reconfiguración podría favorecer la polinización cruzada, mecanismo ya descrito para otras especies de la familia Orchidaceae. Por último, se discuten los caracteres florales presentes en Z. alleniana con otras especies estrechamente emparentadas
Contagion or Confusion? Why Conflicts Cluster in Space
Civil wars cluster in space as well as time. In this study, we develop and evaluate empirically alternative explanations for this observed clustering. We consider whether the spatial pattern of intrastate conflict simply stems from a similar distribution of relevant country attributes or whether conflicts indeed constitute a threat to other proximate states. Our results strongly suggest that there is a genuine neighborhood effect of armed conflict, over and beyond what individual country characteristics can account for. We then examine whether the risk of contagion depends on the degree of exposure to proximate conflicts. Contrary to common expectations, this appears not to be the case. Rather, we find that conflict is more likely when there are ethnic ties to groups in a neighboring conflict and that contagion is primarily a feature of separatist conflicts. This suggests that transnational ethnic linkages constitute a central mechanism of conflict contagion. © 2008 International Studies Association
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