348 research outputs found
Time-of-Flight Photon Spectroscopy: A Simple Scheme To Monitor Simultaneously Spectral and Temporal Fluctuations of Emission on Single Nanoparticles
Here we report on a novel scheme for spectral analysis that exploits the wavelength dependence of the time-of-flight of a photon in a dispersive medium. This versatile and cost-effective method, named time-of-flight photon spectroscopy (TOFPS), has the major advantage of being compatible with time-correlated single-photon counting experiments. Consequently, each photon acquired during an experiment is characterized by two parameters, its absolute time of arrival and its color, respectively. As a result, the spectral and temporal fluctuations of the emission of a single nano-object can be derived from a single measurement. As a proof of the concept, we demonstrate in the paper that the method can be used to perform Raman spectroscopy as well as fluorescence spectroscopy. We emphasize that TOFPS proves to be very efficient for improving signal-to-noise ratio in fluorescence correlation spectroscopy measurements by subsequent spectral filtering and to record luminescence spectra from single metallic particles. We demonstrate that the opportunity of simultaneously recording spectral and temporal fluctuations could be used to sort particles of different shapes inside a sample. TOFPS furthermore allows developing a new type of time interval distribution analysis which correlates the time interval between two photons and their corresponding color shift. It is applied to the analysis of the two-photon excited luminescence of a single gold nanorod. This method has a potential for a broad range of applications, among which time-resolved SERS spectroscopy and analysis of the dynamics of emission processes can be handled with new statistical approaches based on the correlation of spectral and temporal fluctuations
One-photon excited luminescence of single gold particles diffusing in solution under pulsed illumination
Here we report on the visible luminescence of single gold nanospherical particles diffusing in water excited by a pulsed-laser at 488 nm. The signal studied by fluorescence correlation spectroscopy does not display the expected characteristics. The main deviation is obtained for the diffusion time that depends on the laser irradiance. Additional advanced methods of measurements have been implemented to further characterize the emission. These methods have allowed us to demonstrate that the luminescence does not blink even in the picosecond domain and that it does not photobleach either. The comparison between the signals obtained under pulsed and continuous excitations at the same wavelength suggests that the increase in the particle temperature plays a role in the non-linear increase in the luminescence intensity with the excitation power. As in the case of two-photon excited luminescence, it implies that a model describing the luminescence process for a single particle diffusing in liquid must take into account the whole system composed of the gold particle, the capping ligands and the surrounding water
All My Animals Are Equal, but None Can Survive without the Horse’. The Contribution of Working Equids to the Livelihoods of Women across Six Communities in the Chimaltenango Region of Guatemala
SIMPLE SUMMARY: Working equids are often absent from higher level policy interventions, and the global standard of their welfare is low. Understanding the social and cultural context of their contributions to human livelihoods generates evidence supporting the importance of their inclusion in livestock welfare programmes. Although there is increasing evidence globally that working equids contribute to women’s livelihoods and that women facilitate equid welfare, there is a well recognised gender gap in access to extension services. This study aims to investigate how working equids contribute to women’s livelihoods in six communities in Guatemala, using information from 34 face-to-face interviews. Results show that working equids support women’s livelihoods by generating income, saving time, feeding livestock and reducing domestic drudgery. Thirty-two women played a major role in the daily husbandry of working equids, and 31 expressed an interest in gaining more knowledge in equid care. This study explores the relationship between working equids and women in a local context, using the concept of ‘One Welfare’, and investigates the knowledge gaps that exist in the daily husbandry of horses, donkeys and mules. It emphasises the need for equid welfare organisations to understand women’s roles in their target communities and recognise what prevents women from accessing educational resources. ABSTRACT: It is widely assumed that working equid husbandry is carried out by men, and women are often not recognised as facilitating equid welfare. The aim of this study is to investigate how working equids contribute to women’s livelihoods in six of the World Horse Welfare programme target communities in Guatemala and determine what roles women have in their care. Thirty-four face-to-face interviews were carried out and data were analysed using both quantitative and qualitative methods. This study found that working equids support women by reducing domestic drudgery, generating income, feeding livestock and saving time. Thirty-two women played a major role in the care of one or more equids, and overall, women did not feel that they knew enough about equid husbandry. Thirty-one women said they would attend training opportunities if the advertising was clear and they felt that women were able to join. This study recognises the contribution of working equids to women’s livelihoods, describes the roles women play in equid husbandry and addresses the discrepancies between women’s roles and their capacity to undertake these tasks. This emphasises the need for extension services to include and cater for women, improving equid welfare and their ability to continue supporting women’s livelihoods
Exploring the Botanical Wonders of Tarenna Asiatica (L.) Kuntze Ex K. Schum
Tarenna asiatica (L.) Kuntze ex K. Schum, a widely distributed plant species belonging to the Rubiaceae family, has been traditionally utilized in various herbal preparations across different cultures for its purported medicinal properties. This comprehensive review aims to consolidate and evaluate the existing knowledge regarding the botanical characteristics, phytochemical constituents, and pharmacological attributes of Tarenna asiatica. Botanically, Tarenna asiatica is described in terms of its taxonomic classification, morphological features, geographic distribution, and ecological preferences. Understanding the plant\u27s botanical aspects is essential for its proper identification and sustainable utilization. The phytochemical profile of Tarenna asiatica is explored, with a focus on its secondary metabolites such as alkaloids, flavonoids, terpenoids, and phenolic compounds. These bioactive constituents have been extensively studied and are known to impart various biological activities to the plant. Furthermore, this review comprehensively summarizes the pharmacological properties of Tarenna asiatica as reported in the literature. These encompass a wide range of activities, including antioxidant, anti-inflammatory, antimicrobial, anticancer, analgesic, and anti-diabetic effects, among others. The mechanisms of action underlying these pharmacological activities are discussed in detail, shedding light on the potential therapeutic applications of Tarenna asiatica
Influence of polarization and wavelength on two-photon excited luminescence of single gold nanospheres
The Brownian rotation of a nearly spherical gold particle capped with ligands can be observed in the correlation profile of the intensity of the two-photon excited luminescence. Here we report on a multi-parameter study of the luminescence properties, including spectral and polarization analysis of the signal at the single particle level. First, the data confirm the role of the radiative de-excitation of the surface plasmons in the luminescence process. Secondly, the results obtained at low power indicate that the capped particle in water can be approximatively described as a spherical rotor acting in the far-field as a point-like absorption and emission dipole of fixed directions. In addition, we show that the dynamics of the ligands, induced by the heat transfer from the particle to its environment, can be partly controlled by the choice of excitation wavelength
Even obligate symbioses show signs of ecological contingency: Impacts of symbiosis for an invasive stinkbug are mediated by host plant context
Many species interactions are dependent on environmental context, yet the benefits of obligate, mutualistic microbial symbioses to their hosts are typically assumed to be universal across environments. We directly tested this assumption, focusing on the symbiosis between the sap‐feeding insect Megacopta cribraria and its primary bacterial symbiont Candidatus Ishikawaella capsulata. We assessed host development time, survival, and body size in the presence and absence of the symbiont on two alternative host plants and in the insects\u27 new invasive range. We found that association with the symbiont was critical for host survival to adulthood when reared on either host plant, with few individuals surviving in the absence of symbiosis. Developmental differences between hosts with and without microbial symbionts, however, were mediated by the host plants on which the insects were reared. Our results support the hypothesis that benefits associated with this host–microbe interaction are environmentally contingent, though given that few individuals survive to adulthood without their symbionts, this may have minimal impact on ecological dynamics and current evolutionary trajectories of these partners
Amidated and ibuprofen-conjugated kyotorphins promote neuronal rescue and memory recovery in cerebral hypoperfusion dementia model
Copyright © 2016 Sá Santos, Santos, Pinto, Ramu, Heras, Bardaji, Tavares and Castanho. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited
and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.Chronic brain ischemia is a prominent risk factor for neurological dysfunction and progression for dementias, including Alzheimer's disease (AD). In rats, permanent bilateral common carotid artery occlusion (2VO) causes a progressive neurodegeneration in the hippocampus, learning deficits and memory loss as it occurs in AD. Kyotorphin (KTP) is an endogenous antinociceptive dipeptide whose role as neuromodulator/neuroprotector has been suggested. Recently, we designed two analgesic KTP-derivatives, KTP-amide (KTP-NH2) and KTP-NH2 linked to ibuprofen (IbKTP-NH2) to improve KTP brain targeting. This study investigated the effects of KTP-derivatives on cognitive/behavioral functions (motor/spatial memory/nociception) and hippocampal pathology of female rats in chronic cerebral hypoperfusion (2VO-rat model). 2VO-animals were treated with KTP-NH2 or IbKTP-NH2 for 7 days at weeks 2 and 5 post-surgery. After behavioral testing (week 6), coronal sections of hippocampus were H&E-stained or immunolabeled for the cellular markers GFAP (astrocytes) and NFL (neurons). Our findings show that KTP-derivatives, mainly IbKTP-NH2, enhanced cognitive impairment of 2VO-animals and prevented neuronal damage in hippocampal CA1 subfield, suggesting their potential usefulness for the treatment of dementia.Funding was provided by the Portuguese Agency Fundação para a Ciência e a Tecnologia SFRH/BPD/79542/2011 fellowship)info:eu-repo/semantics/publishedVersio
Establishing evidence-based decision-making mechanism in a health eco-system and its linkages with health service coverage in 25 high-priority districts of Uttar Pradesh, India
Abstract
Background
Achievement of successful health outcomes depends on evidence-based programming and implementation of effective health interventions. Routine Health Management Information System is one of the most valuable data sets to support evidence-based programming, however, evidence on systemic use of routine monitoring data for problem-solving and improving health outcomes remain negligible. We attempt to understand the effects of systematic evidence-based review mechanism on improving health outcomes in Uttar Pradesh, India.
Methods
Data comes from decision-tracking system and routine health management information system for period Nov-2017 to Mar-2019 covering 6963 health facilities across 25 high-priority districts of the state. Decision-tracking data captured pattern of decisions taken, actions planned and completed, while the latter one provided information on service coverage outcomes over time. Three service coverage indicators, namely, pregnant women receiving 4 or more times ANC and haemoglobin testing during pregnancy, delivered at the health facility, and receive post-partum care within 48 h of delivery were used as outcomes. Univariate and bivariate analyses were conducted.
Results
Total 412 decisions were taken during the study reference period and a majority were related to ante-natal care services (31%) followed by delivery (16%) and post-natal services (16%). About 21% decisions-taken were focused on improving data quality. By 1 year, 67% of actions planned based on these decisions were completed, 26% were in progress, and the remaining 7% were not completed. We found that, over a year, districts witnessing > 20 percentage-point increase in outcomes were also the districts with significantly higher action completion rates (> 80%) compared to the districts with < 10 percentage-point increase in outcomes having completion of action plans around 50–70%.
Conclusions
Findings revealed a significantly higher improvement in coverage outcomes among the districts which used routine health management data to conduct monthly review meetings and had high actions completion rates. A data-based review-mechanisms could specifically identify programmatic gaps in service delivery leading to strategic decision making by district authorities to bridge the programmatic gaps. Going forward, establishing systematic evidence-based review platforms can be an important strategy to improve health outcomes and promote the use of routine health monitoring system data in any setting
CYP1B1-RMDN2 Alzheimer’s disease endophenotype locus identified for cerebral tau PET
Determining the genetic architecture of Alzheimer’s disease pathologies can enhance mechanistic understanding and inform precision medicine strategies. Here, we perform a genome-wide association study of cortical tau quantified by positron emission tomography in 3046 participants from 12 independent studies. The CYP1B1-RMDN2 locus is associated with tau deposition. The most significant signal is at rs2113389, explaining 4.3% of the variation in cortical tau, while APOE4 rs429358 accounts for 3.6%. rs2113389 is associated with higher tau and faster cognitive decline. Additive effects, but no interactions, are observed between rs2113389 and diagnosis, APOE4, and amyloid beta positivity. CYP1B1 expression is upregulated in AD. rs2113389 is associated with higher CYP1B1 expression and methylation levels. Mouse model studies provide additional functional evidence for a relationship between CYP1B1 and tau deposition but not amyloid beta. These results provide insight into the genetic basis of cerebral tau deposition and support novel pathways for therapeutic development in AD
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