23 research outputs found
Contrasting strategies of hydraulic control in two codominant temperate tree species
Biophysical controls on plant water status exist at the leaf, stem, and root levels. Therefore, we pose that hydraulic strategy is a combination of traits governing water use at each of these three levels. We studied sap flux, stem water storage, stomatal conductance, photosynthesis, and growth of red oaks (Quercus rubra) and red maples (Acer rubrum). These species differ in stomatal hydraulic strategy and xylem architecture and may root at different depths. Stable isotope analysis of xylem water was used to identify root water uptake depth. Oaks were shown to access a deeper water source than maples. During nonâlimiting soil moisture conditions, transpiration was greater in maples than in oaks. However, during a soil dry down, transpiration and stem water storage decreased by more than 80% and 28% in maples but only by 31% and 1% in oaks. We suggest that the preferential use of deep water by red oaks allows the species to continue transpiration and growth during soil water limitations. In this case, deeper roots may provide a buffer against droughtâinduced mortality. Using 14Â years of growth data, we show that maple growth correlates with mean annual soil moisture at 30Â cm but oak growth does not. The observed responses of oak and maple to drought were not able to be explained by leaf and xylem physiology alone. We employed the Finiteâdifference Ecosystemâscale Tree Crown Hydrodynamics model version 2 plant hydrodynamics model to demonstrate the influence of root, stem, and leaf controls on treeâlevel transpiration. We conclude that all three levels of hydraulic traits are required to define hydraulic strategy.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136732/1/eco1815_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136732/2/eco1815.pd
Relative effectiveness and safety of pharmacotherapeutic agents for patent ductus arteriosus (PDA) in preterm infants: A protocol for a multicentre comparative effectiveness study (CANRxPDA)
Introduction Patent ductus arteriosus (PDA) is the most common cardiovascular problem that develops in preterm infants and evidence regarding the best treatment approach is lacking. Currently available medical options to treat a PDA include indomethacin, ibuprofen or acetaminophen. Wide variation exists in PDA treatment practices across Canada. In view of this large practice variation across Canadian neonatal intensive care units (NICUs), we plan to conduct a comparative effectiveness study of the different pharmacotherapeutic agents used to treat the PDA in preterm infants. Methods and analysis A multicentre prospective observational comparative-effectiveness research study of extremely preterm infants born 29 weeks gestational age with an echocardiography confirmed PDA will be conducted. All participating sites will self-select and adhere to one of the following primary pharmacotherapy protocols for all preterm babies who are deemed to require treatment. Standard dose ibuprofen (10 mg/kg followed by two doses of 5 mg/kg at 24 hours intervals) irrespective of postnatal age (oral/intravenous). Adjustable dose ibuprofen (oral/intravenous) (10 mg/kg followed by two doses of 5 mg/kg at 24 hours intervals if treated within the first 7 days after birth. Higher doses of ibuprofen up to 20 mg/kg followed by two doses of 10 mg/kg at 24 hours intervals if treated after the postnatal age cut-off for lower dose as per the local centre policy). Acetaminophen (oral/intravenous) (15 mg/kg every 6 hours) for 3-7 days. Intravenous indomethacin (0.1-0.3 mg/kg intravenous every 12-24 hours for a total of three doses). Outcomes The primary outcome is failure of primary pharmacotherapy (defined as need for further medical and/or surgical/interventional treatment following an initial course of pharmacotherapy). The secondary outcomes include components of the primary outcome as well as clinical outcomes related to response to treatment or adverse effects of treatment. Sites and sample size The study will be conducted in 22 NICUs across Canada with an anticipated enrollment of 1350 extremely preterm infants over 3 years. Analysis To examine the relative effectiveness of the four treatment strategies, the primary outcome will be compared pairwise between the treatment groups using Ï 2 test. Secondary outcomes will be compared pairwise between the treatment groups using Ï 2 test, Student\u27s t-test or Wilcoxon rank sum test as appropriate. To further examine differences in the primary and secondary outcomes between the four groups, multiple logistic or linear regression models will be applied for each outcome on the treatment groups, adjusted for potential confounders using generalised estimating equations to account for within-unit-clustering. As a sensitivity analysis, the difference in the primary and secondary outcomes between the treatment groups will also be examined using propensity score method with inverse probability weighting approach. Ethics and dissemination The study has been approved by the IWK Research Ethics Board (#1025627) as well as the respective institutional review boards of the participating centres. © 2021 Author(s). Published by BMJ
Interactive âVideo Doctorâ Counseling Reduces Drug and Sexual Risk Behaviors among HIV-Positive Patients in Diverse Outpatient Settings
, an interactive, patient-tailored computer program, was developed in the United States to improve clinic-based assessment and counseling for risky behaviors.We conducted a parallel groups randomized controlled trial (December 2003âSeptember 2006) at 5 San Francisco area outpatient HIV clinics. Eligible patients (HIV-positive English-speaking adults) completed an in-depth computerized risk assessment. Participants reporting substance use or sexual risks (nâ=â476) were randomized in stratified blocks. The intervention group received tailored risk-reduction counseling from a âVideo Doctorâ via laptop computer and a printed Educational Worksheet; providers received a Cueing Sheet on reported risks. Compared with control, fewer intervention participants reported continuing illicit drug use (RR 0.81, 95% CI: 0.689, 0.957, pâ=â0.014 at 3 months; and RR 0.65, 95% CI: 0.540, 0.785, p<0.001 at 6 months) and unprotected sex (RR 0.88, 95% CI: 0.773, 0.993, pâ=â0.039 at 3 months; and RR 0.80, 95% CI: 0.686, 0.941, pâ=â0.007 at 6 months). Intervention participants reported fewer mean days of ongoing illicit drug use (-4.0 days vs. -1.3 days, pâ=â0.346, at 3 months; and -4.7 days vs. -0.7 days, pâ=â0.130, at 6 months) than did controls, and had fewer casual sex partners at (â2.3 vs. â1.4, pâ=â0.461, at 3 months; and â2.7 vs. â0.6, pâ=â0.042, at 6 months)., including Video Doctor counseling, is an efficacious and appropriate adjunct to risk-reduction efforts in outpatient settings, and holds promise as a public health HIV intervention
Frequent disruption of the RB pathway in indolent follicular lymphoma suggests a new combination therapy.
Loss of cell cycle controls is a hallmark of cancer and has a well-established role in aggressive B cell malignancies. However, the role of such lesions in indolent follicular lymphoma (FL) is unclear and individual lesions have been observed with low frequency. By analyzing genomic data from two large cohorts of indolent FLs, we identify a pattern of mutually exclusive (P = 0.003) genomic lesions that impair the retinoblastoma (RB) pathway in nearly 50% of FLs. These alterations include homozygous and heterozygous deletions of the p16/CDKN2a/b (7%) and RB1 (12%) loci, and more frequent gains of chromosome 12 that include CDK4 (29%). These aberrations are associated with high-risk disease by the FL prognostic index (FLIPI), and studies in a murine FL model confirm their pathogenic role in indolent FL. Increased CDK4 kinase activity toward RB1 is readily measured in tumor samples and indicates an opportunity for CDK4 inhibition. We find that dual CDK4 and BCL2 inhibitor treatment is safe and effective against available models of FL. In summary, frequent RB pathway lesions in indolent, high-risk FLs indicate an untapped therapeutic opportunity
Biophysical Evidence for a Molecular Interaction between Proteoglycan 4 and Hyaluronan in Solution: Effect of Exposure to a Zwitterionic Detergent on Cartilage Boundary Lubricating Function
Proteoglycan 4 (PRG4) and hyaluronan (HA) are key synovial fluid constituents
that contribute synergistically to cartilage boundary lubrication through an undefined
mechanism. PRG4 monomers and multimers have previously been separated using size
exclusion chromatography with a buffer containing the zwitterionic detergent CHAPS.
However, CHAPS may alter the ability of PRG4 to interact with HA and synergistically
reduce friction. The objectives of this thesis were to (1) assess the size distribution of
PRG4, HA, and PRG4+HA in solution, and (2) determine the effect of exposing PRG4 to
CHAPS on the size distribution, cartilage boundary lubricating ability, and cartilage
adsorption of PRG4+HA. The size distribution of PRG4+HA was less than PRG4 and
HA. Exposure to CHAPS irreversibly altered the size distribution, cartilage boundary
lubricating ability, and cartilage adsorption of PRG4+HA. These results suggest a
hydrophobic molecular interaction exists between PRG4 and HA, both in solution and at
the articular cartilage surface
INVESTIGATION OF THE MOLECULAR CONSEQUENCES OF CHRONIC OVERACTIVATION OF HYPOTHALAMIC POMC NEURONS IN VITRO
Special Educatorsâ Training and Preparedness to Write Individualized Education Programs
Over the last decade, there has been ample evidence reporting the lack of high-quality and compliant Individualized Education Programs (IEP) in the United States. This problem has many consequences, including poor student outcomes and failure to follow legal due process. Despite these consequences, research has not thoroughly examined the perspectives and needs of special educators on IEP development or the role of pre-service training on special educatorsâ ability to write high-quality, compliant IEPs. To address this gap, we surveyed 218 Pennsylvania special educators to examine their perspectives on the sufficiency of their pre-service training to write high-quality IEPs. We also gathered data on the types of training and support special educators need to successfully write IEPs. Results provide information on needed teacher preparation program components, supports for in-service special educators when writing IEPs, and areas for future professional development. Implications and future directions for training on writing IEPs are discussed
New Insights on the Role of Bioactive Food Derivatives in Neurodegeneration and Neuroprotection
Over the last three decades, neurodegenerative diseases have received increasing attention due to their frequency in the aging population and the social and economic burdens they are posing. In parallel, an era's worth of research in neuroscience has shaped our current appreciation of the complex relationship between nutrition and the central nervous system. Particular branches of nutrition continue to galvanize neuroscientists, in particular the diverse roles that bioactive food derivatives play on health and disease. Bioactive food derivatives are nowadays recognized to directly impact brain homeostasis, specifically with respect to their actions on cellular mechanisms of oxidative stress, neuroinflammation, mitochondrial dysfunction, apoptosis and autophagy. However, ambiguities still exist regarding the significance of the influence of bioactive food derivatives on human health. In turn, gut microbiota dysbiosis is emerging as a novel player in the pathogenesis of neurodegenerative diseases. Currently, several routes of communication exist between the gut and the brain, where molecules are either released in the bloodstream or directly transported to the CNS. As such, bioactive food derivatives can modulate the complex ecosystem of the gut-brain axis, thus, targeting this communication network holds promises as a neuroprotective tool. This review aims at addressing one of the emerging aspects of neuroscience, particularly the interplay between food bioactive derivatives and neurodegeneration. We will specifically address the role that polyphenols and omega-3 fatty acids play in preventing neurodegenerative diseases and how dietary intervention complements available pharmacological approaches
Meta-Analysis of Mathematics Interventions for Students with Autism Spectrum Disorder
Prior reviews (e.g., Gevarter et al., 2016; Hart Barnett & Cleary, 2015; King, Lemons, & Davidson, 2016) on mathematics interventions for students identified with Autism Spectrum Disorder have provided useful information for practitioners and have identified areas for additional research. We aim to extend prior work by updating the literature search and evaluating the boundaries of intervention effects through multilevel modeling procedures