471 research outputs found
Photosynthesis dependent acidification of perialgal vacuoles in theParamedum bursaria/Chlorella symbiosis. Visualization by monensin
After treatment with the carboxylic ionophore monensin theChlorella containing perialgal vacuoles of the greenParamecium bursaria swell. TheParamecium cells remain motile at this concentration for at least one day. The swelling is only observed in illuminated cells and can be inhibited by DCMU. We assume that during photosynthesis the perialgal vacuoles are acidified and that monensin exchanges H+ ions against monovalent cations (here K+). In consequence the osmotic value of the vacuoles increases. The proton gradient is believed to drive the transport of maltose from the symbiont into the host. Another but light independent effect of the monensin treatment is the swelling of peripheral alveoles of the ciliates, likewise indicating that the alveolar membrane contains an active proton pump
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The cost of a primary care-based childhood obesity prevention intervention
Background: United States pediatric guidelines recommend that childhood obesity counseling be conducted in the primary care setting. Primary care-based interventions can be effective in improving health behaviors, but also costly. The purpose of this study was to evaluate the cost of a primary care-based obesity prevention intervention targeting children between the ages of two and six years who are at elevated risk for obesity, measured against usual care. Methods: High Five for Kids was a cluster-randomized controlled clinical trial that aimed to modify childrenâs nutrition and TV viewing habits through a motivational interviewing intervention. We assessed visit-related costs from a societal perspective, including provider-incurred direct medical costs, provider-incurred equipment costs, parent time costs and parent out-of-pocket costs, in 2011 dollars for the intervention (n = 253) and usual care (n = 192) groups. We conducted a net cost analysis using both societal and health plan costing perspectives and conducted one-way sensitivity and uncertainty analyses on results. Results: The total costs for the intervention group and usual care groups in the first year of the intervention were 64,522, 12,192 (95% CI [13,174]). The mean costs for the intervention and usual care groups were 255, 63 (95% CI [69]) per child, respectively, for a incremental difference of 191, $202]) per child. Children in the intervention group attended a mean of 2.4 of a possible 4 in-person visits and received 0.45 of a possible 2 counseling phone calls. Provider-incurred costs were the primary driver of cost estimates in sensitivity analyses. Conclusions: High Five for Kids was a resource-intensive intervention. Further studies are needed to assess the cost-effectiveness of the intervention relative to other pediatric obesity interventions. Trial registration ClinicalTrials.gov Identifier: NCT00377767
Telomere length associations with cognition depend on Alzheimer's disease biomarkers
Introduction
While telomere shortening, a marker of cellular aging, may impact the progression of ageârelated neurodegenerative diseases, its association with cognition is unclear, particularly in the context of Alzheimer's disease (AD) pathology.
Methods
Telomere, cognitive, and CSF data from 482 participants in the AD Neuroimaging Initiative (148 cognitively normal, 283 mild cognitive impairment, 51 AD) was leveraged to assess telomere length associations with cognition (measured by memory and executive function) and interactions with CSF amyloidâβ, tau, and APOEâÎľ4. Secondary analyses assessed brain volume and thickness outcomes.
Results
Longer telomeres at baseline were associated with faster executive function decline. Amyloidâβ and tau interacted with telomere length on cognition, with longer telomeres related to faster decline among biomarkerâpositive individuals.
Discussion
Telomere associations with cognition shift with AD progression, with longer telomeres related to worse outcomes as pathology increases, highlighting the need for further investigation of telomere length along the AD neuropathological cascade
Biological correlates of elevated soluble TREM2 in cerebrospinal fluid
Cerebrospinal fluid (CSF) soluble triggering receptor expressed on myeloid cells-2 (sTREM2) is an emerging biomarker of neuroinflammation in Alzheimer's disease (AD). Yet, sTREM2 expression has not been systematically evaluated in relation to concomitant drivers of neuroinflammation. While associations between sTREM2 and tau in CSF are established, we sought to determine additional biological correlates of CSF sTREM2 during the prodromal stages of AD by evaluating CSF Aβ species (Aβx-40), a fluid biomarker of blood-brain barrier integrity (CSF/plasma albumin ratio), and CSF biomarkers of neurodegeneration measured in 155 participants from the Vanderbilt Memory and Aging Project. A novel association between high CSF levels of both sTREM2 and Aβx-40 was observed and replicated in an independent dataset. Aβx-40 levels, as well as the CSF/plasma albumin ratio, explained additional and unique variance in sTREM2 levels above and beyond that of CSF biomarkers of neurodegeneration. The component of sTREM2 levels correlated with Aβx-40 levels best predicted future cognitive performance. We highlight potential contributions of Aβ homeostasis and blood-brain barrier integrity to elevated CSF sTREM2, underscoring novel biomarker associations relevant to disease progression and clinical outcome measures
Using Unoccupied Aerial Vehicles to Map and Monitor Changes in Emergent Kelp Canopy after an Ecological Regime Shift
Kelp forests are complex underwater habitats that form the foundation of many nearshore marine environments and provide valuable services for coastal communities. Despite their ecological and economic importance, increasingly severe stressors have resulted in declines in kelp abundance in many regions over the past few decades, including the North Coast of California, USA. Given the significant and sustained loss of kelp in this region, management intervention is likely a necessary tool to reset the ecosystem and geospatial data on kelp dynamics are needed to strategically implement restoration projects. Because canopy-forming kelp forests are distinguishable in aerial imagery, remote sensing is an important tool for documenting changes in canopy area and abundance to meet these data needs. We used small unoccupied aerial vehicles (UAVs) to survey emergent kelp canopy in priority sites along the North Coast in 2019 and 2020 to fill a key data gap for kelp restoration practitioners working at local scales. With over 4,300 hectares surveyed between 2019 and 2020, these surveys represent the two largest marine resource-focused UAV surveys conducted in California to our knowledge. We present remote sensing methods using UAVs and a repeatable workflow for conducting consistent surveys, creating orthomosaics, georeferencing data, classifying emergent kelp and creating kelp canopy maps that can be used to assess trends in kelp canopy dynamics over space and time. We illustrate the impacts of spatial resolution on emergent kelp canopy classification between different sensors to help practitioners decide which data stream to select when asking restoration and management questions at varying spatial scales. Our results suggest that high spatial resolution data of emergent kelp canopy from UAVs have the potential to advance strategic kelp restoration and adaptive management
Impact of Motivational Interviewing by Social Workers on Service Users - a systematic review
Purpose: This systematic review was undertaken to determine the effectiveness of motivational interviewing (MI), by social workers, on service user outcomes.
Methods: A literature search was undertaken between 2007 and 2018. All eligible studies were analyzed using the Critical Appraisal Skills Programme tool. As heterogeneity was high, a narrative synthesis approach was employed, using thematic analysis for categorizing data.
Results: Eleven studies met the inclusion criteria and were included in this review. MI had a positive effect on service user experience, but this was not consistent. Training was variable, but the evidence suggests that practitionerâs need ongoing training, supervision, or coaching while providing MI.
Discussion: There is a paucity of research examining the impact of MI on children, which was a limitation of this review. There is a need for more qualitative research to surface views and experience of service users to determine why MI is effective
Identifying Mechanisms of Normal Cognitive Aging Using a Novel Mouse Genetic Reference Panel.
Developing strategies to maintain cognitive health is critical to quality of life during aging. The basis of healthy cognitive aging is poorly understood; thus, it is difficult to predict who will have normal cognition later in life. Individuals may have higher baseline functioning (cognitive reserve) and others may maintain or even improve with age (cognitive resilience). Understanding the mechanisms underlying cognitive reserve and resilience may hold the key to new therapeutic strategies for maintaining cognitive health. However, reserve and resilience have been inconsistently defined in human studies. Additionally, our understanding of the molecular and cellular bases of these phenomena is poor, compounded by a lack of longitudinal molecular and cognitive data that fully capture the dynamic trajectories of cognitive aging. Here, we used a genetically diverse mouse population (B6-BXDs) to characterize individual differences in cognitive abilities in adulthood and investigate evidence of cognitive reserve and/or resilience in middle-aged mice. We tested cognitive function at two ages (6 months and 14 months) using y-maze and contextual fear conditioning. We observed heritable variation in performance on these traits
GRB 050505: A high redshift burst discovered by Swift
We report the discovery and subsequent multi-wavelength afterglow behaviour
of the high redshift (z = 4.27) Gamma Ray Burst GRB 050505. This burst is the
third most distant burst, measured by spectroscopic redshift, discovered after
GRB 000131 (z = 4.50) and GRB 050904 (z = 6.29). GRB 050505 is a long GRB with
a multipeaked gamma-ray light curve, with a duration of T_90 = 63+/-2 s and an
inferred isotropic release in gamma-rays of ~4.44 x 10^53 ergs in the 1-10^4
keV rest frame energy range. The Swift X-Ray Telescope followed the afterglow
for 14 days, detecting two breaks in the light curve at 7.4(+/-1.5) ks and 58.0
(+9.9/-15.4) ks after the burst trigger. The power law decay slopes before,
between and after these breaks were 0.25 (+0.16/-0.17), 1.17 (+0.08/-0.09) and
1.97 (+0.27/-0.28) respectively. The light curve can also be fit with a
`smoothly broken' power law model with a break observed at ~ T+18.5 ks, with
decay slopes of ~0.4 and ~1.8 before and after the break respectively. The
X-ray afterglow shows no spectral variation over the course of the Swift
observations, being well fit with a single power law of photon index ~1.90.
This behaviour is expected for the cessation of continued energisation of the
ISM shock followed by a break caused by a jet, either uniform or structured.
Neither break is consistent with a cooling break. The spectral energy
distribution indeed shows the cooling frequency to be below the X-ray but above
optical frequencies. The optical -- X-ray spectrum also shows that there is
significant X-ray absorption in excess of that due to our Galaxy but very
little optical/UV extinction, with E(B-V) ~0.10 for a SMC-like extinction
curve.Comment: 9 pages, 6 figures. Accepted by MNRA
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