Fluxional Behaviour of Phosphole and Phosphine Ligands on Triosmium Clusters

International audienceThe unsaturated cluster [Os3(μ-H)2(CO)10] reacts with a variety of π-conjugated phosphole ligands: 2,5-bis(2-thienyl)-1-phenylphosphole, 2,5-bis(2-pyridyl)-1-phenylphosphole, and 1,2,5-triphenylphosphole, to give the monosubstituted [Os3(μ-H)(H)(CO)10(P)] and [Os3(μ-H)2(CO)9(P)] derivatives. Variable-temperature 1H NMR studies for the decacarbonyltriosmium complexes show that the hydride ligands undergo fluxional behavior and its decarbonylation gave the nonacarbonyl unsaturated species with equivalent hydrides. An X-ray crystallographic analysis of [Os3(μ-H)2(CO)9(P)] (2b) (P = 1,2,5-triphenylphosphole) is reported. From 2,5-bis(2-pyridyl)-1-phenylphosphole four isomers are obtained, the 1H NMR spectrum at low temperature indicates that the phosphole ligand may occupy pseudoaxial and equatorial sites at one of the osmium atoms bearing the bridging hydride. The reaction of [Os3(CO)10(CH3CN)2] with cyanoethyldiphenylphosphine affords mono- and bis(phosphine)-substituted clusters. The X-ray crystal structure of the monosubstituted [Os3(CO)11(η1-PC15H14N)] (3) derivative is discussed. The dynamic behavior observed for [Os3(CO)10(η1-PC15H14N)2] (4) is studied by variable-temperature 1H and 31P{1H} NMR spectroscopy. The latter studies show a mixture of two geometric isomers, which are in dynamic equilibrium at room temperature where the 1,2-trans–trans isomer (4a) is favored, whose molecular structure has been determined by X-ray crystallography

Compromiso Social - Ético del Personal Docente desde el Paradigma de la Complejidad

The aim of this study is ethically social compromise and teachers from the perspective of complexity in educational institutions. In principle, the researchers turn to the literature review framed in socio-critical theories that permeate teaching action from its social commitment with authors like Garcia and Martinez; also cites Rodrigo Morin and from an ethical perspective. Then perform the recognition of the scenario that allows them to contextual and geographical description where the "Hero Nigale" National Basic School, likewise made the approach to the context in which the investigation was carried out and subsequently socio-political aspects of the municipality Valmore Rodriguez described; then selected in the research process community is involved, which allows collecting information through conversations and interviews with key informants; thus generating awareness spaces for reflection and discussion with stakeholders. the qualitative paradigm is inserted under the participatory action research method IAP according Latorre (2010), applying the interview technique for teachers who work in the institution. The results of this research reveal in educational interest to overcome the weaknesses in the educational process, likewise strengthen oriented social transformation practices, which involves being responsible, equitable, fair, focused on building citizens capable of being, apprehend, live and coexist with others in the same society

Understanding the resources, barriers, facilitators and interests about aging and dementia research of community members from the Rio Grande Valley

Background: One of ten people aged 65 develops Alzheimer’s Disease and it is one of the sixth-leading cause of death in the United States. The Rio Grande Valley (RGV) is mostly constituted by Hispanic/Latinos (93%), a population that has a 1.5X increased risk of AD onset. Nevertheless, there are not enough resources to support people living with dementia and their care partners. This study will leverage research efforts deployed by the RGV Alzheimer’s Disease Resource Center for Minority Aging Research to understand the social representations about the resources, barriers, facilitators, and interests of the RGV community about dementia and Alzheimer’s Disease research. Methods: Four focus groups were conducted online via Zoom on April 2022 with a total of 15 participants (people living with dementia, caregivers, and community leaders from the RGV). Interactions occurred at their preferred language, mostly in Spanish and the discussion was based on six semi-structured questions about aging and dementia research. Focus groups were translated to English and analyzed using the Consolidated Framework for Implementation Research (CFIR). Results: Community health workers (promotoras) are one of the most important resources and facilitators in the Valley due to their deep knowledge of the dynamics of the community. The main barrier for dementia and aging research is the lack of information, which leads to fear, and stigmas and ultimately keeping target communities away from the resources. Focus groups served also as a channel of communication. After conducting the focus groups, some of the participants went from being unaware of the presence of Alzheimer’s disease and dementia research in the Valley to deciding about acting toward their prevention and participating in the research. Conclusions: The information collected during the focus groups will be used to strengthen community engagement strategies and to support the design and implementation of health disparities frameworks to facilitate tailoring of our strategies to maximize the impact of the resources developed to be used in the communities of the RGV

Cognitive performance and normative data between Hispanic and non-Hispanic cohorts: Results from the South Texas Alzheimer’s Disease Research Center (ADRC)

Background: The prevalence of Alzheimer\u27s disease and related dementias (ADRD) in the United States was estimated as 6.5 million people in 2022, with a five-fold increase for the Hispanic/Latinx population expected by 2060. The South Texas Alzheimer\u27s Disease Center (STAC) was designated as a new ADRC in 2021 by the National Institute on Aging (NIA) with a specific aim to serve the growing needs of the local underrepresented Hispanic population. As cultural and linguistic factors can impact performance on cognitive tests, the goal of the study was to compare UDS-3 cognitive test raw scores and normative data in Hispanic and non-Hispanic adults without cognitive impairment residing in South Texas. Method: Participants from the STAC cohort completed the Uniform Data Set (UDS), V.3.0, which includes demographics and neuropsychological battery. All batteries were administered in the participants’ preferred language, English. Normative data was calculated using Weintraub et al. (2018)’s age, sex, and education adjusted regression models for UDSNB 3.0. Mean differences between baseline visit raw scores and normative data were compared using independent sample t-tests among Hispanic and non-Hispanic participants. Result: Thirty-four Hispanic (mean age=70.4, 67.6% female) and thirty-eight non-Hispanic (mean age=71.9, 57.9% female) participants were included. Hispanic participants had fewer years of education relative to non-Hispanic participants [M(SD)] = [14.7(2.5)] to [16.5(2.5)], respectively; (t(70.1)=3.0, p =0.004); although, the groups did not differ in age or sex distribution (p\u3e0.05). Hispanic and non-Hispanic participants generally performed equivalently on the neuropsychological battery. However, Hispanics had lower mean raw scores on the Montreal Cognitive Assessment (MoCA) (t(70.8)= 3.6, p Conclusion: Overall, Hispanic and non-Hispanic participants performed similarly on the UDS-3 neuropsychological battery. However, Hispanics had lower mean raw and normative scores on the MINT, as well as the MoCA which also includes language measures. Our findings highlight the importance of future research validating the sensitivity and specificity of normative data used in underrepresented populations, especially those at higher risk for ADRD

Cognitive Decline Associated with Longitudinal Changes in 24-h Ambulatory Blood Pressure Variability

Background: Cognitive decline has been associated with variability in blood pressure (BP). However, whether the increment of the BP variability during follow-up precedes cognitive decline remains undocumented. We aimed this study to investigate cognitive decline in relation to longitudinal changes in 24-h reading-to-reading BP variability. Methods: We conducted an observational longitudinal study that included 717 dementia-free participants from the Maracaibo Aging Study who underwent follow-up assessment in both 24-h ambulatory BP monitoring and cognitive tests between 1998 and 2015. Cognitive domains consisted of selective reminding tests (total, long-term, short-term, and recognition memory) and the Mini-Mental State Examination (MMSE). Cognitive decline was a longitudinal decrease in cognitive scores. Participants underwent 24-h ambulatory BP monitoring between 2-4 times – with at least one-year interval. Systolic and diastolic BP variability was studied during 24-h and divided into daytime (from 06h00 to 23h00), and nighttime (23h00 to 06h00) periods. To account for BP level, we used variability independent of the mean (VIM) to compute systolic and diastolic BP variability. Other measures of BP variability included the nocturnal BP drop in comparison to the daytime BP level, which was estimated as the night-to-day ratio. Statistics included multivariate linear regression mixed models. Results: Overall, the mean age was 65.6±7.36 years old and 66.5% (n=447) of the participants were women. In mixed models, a decline in all memory domains was associated with greater variability in the 24-h, daytime, and nighttime systolic BP during follow-up, with an estimated decline in cognitive scores ranging from -0.2 to -0.04 points per unit increase in VIM systolic BP during follow-up (P values ranged from 0.022 to 0.003). Decline in total, short-term, and MMSE memory domains was associated with greater 24-h and daytime diastolic BP variability (P≤0.015). A lower night-to-day dipping ratio during follow-up increased the risk of cognitive decline, with a -5.8 to -1.6 decline in long-term memory and MMSE scores; respectively (P≤0.037). Conclusions: Cognitive decline associates with greater reading-to-reading 24-h BP variability and lower falls in nocturnal BP over time. These findings might be indicative of deteriorated regulatory mechanisms to maintain steady BP levels as individuals age

The complex hybrid origins of the root knot nematodes revealed through comparative genomics

Meloidogyne root knot nematodes (RKN) can infect most of the world's agricultural crop species and are among the most important of all plant pathogens. As yet however we have little understanding of their origins or the genomic basis of their extreme polyphagy. The most damaging pathogens reproduce by mitotic parthenogenesis and are suggested to originate by interspecific hybridizations between unknown parental taxa. We sequenced the genome of the diploid meiotic parthenogen Meloidogyne floridensis, and use a comparative genomic approach to test the hypothesis that it was involved in the hybrid origin of the tropical mitotic parthenogen M. incognita. Phylogenomic analysis of gene families from M. floridensis, M. incognita and an outgroup species M. hapla was used to trace the evolutionary history of these species' genomes, demonstrating that M. floridensis was one of the parental species in the hybrid origins of M. incognita. Analysis of the M. floridensis genome revealed many gene loci present in divergent copies, as they are in M. incognita, indicating that it too had a hybrid origin. The triploid M. incognita is shown to be a complex double-hybrid between M. floridensis and a third, unidentified parent. The agriculturally important RKN have very complex origins involving the mixing of several parental genomes by hybridization and their extreme polyphagy and agricultural success may be related to this hybridization, producing transgressive variation on which natural selection acts. Studying RKN variation via individual marker loci may fail due to the species' convoluted origins, and multi-species population genomics is essential to understand the hybrid diversity and adaptive variation of this important species complex. This comparative genomic analysis provides a compelling example of the importance and complexity of hybridization in generating animal species diversity more generally

One Health – an Ecological and Evolutionary Framework for tackling Neglected Zoonotic Diseases

Understanding the complex population biology and transmission ecology of multihost parasites has been declared as one of the major challenges of biomedical sciences for the 21st century and the Neglected Zoonotic Diseases (NZDs) are perhaps the most neglected of all the Neglected Tropical Diseases (NTDs). Here we consider how multihost parasite transmission and evolutionary dynamics may affect the success of human and animal disease control programmes, particularly neglected diseases of the developing world. We review the different types of zoonotic interactions that occur, both ecological and evolutionary, their potential relevance for current human control activities, and make suggestions for the development of an empirical evidence base and theoretical framework to better understand and predict the outcome of such interactions. In particular, we consider whether preventive chemotherapy, the current mainstay of NTD control, can be successful without a One Health approach. Transmission within and between animal reservoirs and humans can have important ecological and evolutionary consequences, driving the evolution and establishment of drug resistance, as well as providing selective pressures for spill‐over, host switching, hybridizations and introgressions between animal and human parasites. Our aim here is to highlight the importance of both elucidating disease ecology, including identifying key hosts and tailoring control effort accordingly, and understanding parasite evolution, such as precisely how infectious agents may respond and adapt to anthropogenic change. Both elements are essential if we are to alleviate disease risks from NZDs in humans, domestic animals and wildlife

Hybridization in parasites: consequences for adaptive evolution, pathogenesis and public health in a changing world

[No abstract available

Blending of animal colour patterns by hybridization

Biologists have long been fascinated by the amazing diversity of animal colour patterns. Despite much interest, the underlying evolutionary and developmental mechanisms contributing to their rich variety remain largely unknown, especially the vivid and complex colour patterns seen in vertebrates. Here, we show that complex and camouflaged animal markings can be formed by the 'blending' of simple colour patterns. A mathematical model predicts that crossing between animals having inverted spot patterns (for example, 'light spots on a dark background' and 'dark spots on a light background') will necessarily result in hybrid offspring that have camouflaged labyrinthine patterns as 'blended' intermediate phenotypes. We confirmed the broad applicability of the model prediction by empirical examination of natural and artificial hybrids of salmonid fish. Our results suggest an unexplored evolutionary process by means of 'pattern blending', as one of the possible mechanisms underlying colour pattern diversity and hybrid speciation

Addressing the disparities in dementia risk, early detection and care in Latino populations: Highlights from the Second Latinos and Alzheimer's Symposium

The Alzheimer's Association hosted the second Latinos & Alzheimer's Symposium in May 2021. Due to the COVID-19 pandemic, the meeting was held online over 2 days, with virtual presentations, discussions, mentoring sessions, and posters. The Latino population in the United States is projected to have the steepest increase in Alzheimer's disease (AD) in the next 40 years, compared to other ethnic groups. Latinos have increased risk for AD and other dementias, limited access to quality care, and are severely underrepresented in AD and dementia research and clinical trials. The symposium highlighted developments in AD research with Latino populations, including advances in AD biomarkers, and novel cognitive assessments for Spanish-speaking populations, as well as the need to effectively recruit and retain Latinos in clinical research, and how best to deliver health-care services and to aid caregivers of Latinos living with AD