3,649 research outputs found
ATF3 upregulation in glia during Wallerian degeneration: differential expression in peripheral nerves and CNS white matter
Background: Many changes in gene expression occur in distal stumps of injured nerves but the transcriptional control of these events is poorly understood. We have examined the expression of the transcription factors ATF3 and c-Jun by non-neuronal cells during Wallerian degeneration following injury to sciatic nerves, dorsal roots and optic nerves of rats and mice, using immunohistochemistry and in situ hybridization.Results: Following sciatic nerve injury-transection or transection and reanastomosis-ATF3 was strongly upregulated by endoneurial, but not perineurial cells, of the distal stumps of the nerves by 1 day post operation (dpo) and remained strongly expressed in the endoneurium at 30 dpo when axonal regeneration was prevented. Most ATF3+ cells were immunoreactive for the Schwann cell marker, S100. When the nerve was transected and reanastomosed, allowing regeneration of axons, most ATF3 expression had been downregulated by 30 dpo. ATF3 expression was weaker in the proximal stumps of the injured nerves than in the distal stumps and present in fewer cells at all times after injury. ATF3 was upregulated by endoneurial cells in the distal stumps of injured neonatal rat sciatic nerves, but more weakly than in adult animals. ATF3 expression in transected sciatic nerves of mice was similar to that in rats. Following dorsal root injury in adult rats, ATF3 was upregulated in the part of the root between the lesion and the spinal cord (containing Schwann cells), beginning at 1 dpo, but not in the dorsal root entry zone or in the degenerating dorsal column of the spinal cord. Following optic nerve crush in adult rats, ATF3 was found in some cells at the injury site and small numbers of cells within the optic nerve displayed weak immunoreactivity. The pattern of expression of c-Jun in all types of nerve injury was similar to that of ATF3.Conclusion: These findings raise the possibility that ATF3/c-Jun heterodimers may play a role in regulating changes in gene expression necessary for preparing the distal segments of injured peripheral nerves for axonal regeneration. The absence of the ATF3 and c-Jun from CNS glia during Wallerian degeneration may limit their ability to support regeneration
Frequency and timing system for the consolidated DSN and STDN tracking network
The consolidation on the existing Deep Space Network (DSN) and colocated Goddard Spaceflight Tracking and Data Network (STDN) stations into a multiple antenna array is discussed. Each site includes a signal processing center (SPC) centered in an array of four or five antennas each located within approximately 300 to 800 meters of the SPC. A central frequency and timing system (FTS) located in the SPC contains reference frequency, timing and time code generation, and distribution equipment for both the SPC and each antenna with its associated front end antenna control building. The reference frequency distribution and clock equipment are driven by a hydrogen maser as the prime frequency standard with cesium beam frequency standard as the secondary
Effect of strobilurin fungicides on control of early blight (Alternaria solani) and yield of potatoes grown under two N fertility regimes
Early blight, caused by Alternaria solani, is a ubiquitous disease that can reduce potato yield. Adequate crop fertility and appropriate fungicide applications usually suppress the development of this disease. Field trials were established in Prince Edward Island to determine whether strobilurin analogs, namely azoxystrobin and pyraclostrobin, could suppress early blight of potatoes (cvs. Shepody and Russet Burbank) grown under two nitrogen (N) fertility regimes (high or low N). Azoxystrobin and pyraclostrobin were linked to significantly higher total tuber yield for Russet Burbank in 2003 and Shepody in 2004 when compared to plots receiving no strobilurin fungicides. No significant differences in total tuber yield based on N fertility were observed, although the high N rate decreased disease in Russet Burbank control plots in 2004. Due to an absence of early blight in 2003, the increase in Russet Burbank yield may be attributed to the physiological and developmental alterations brought about by strobilurin products in treated plants. In 2004, early blight was severe in inoculated control plots, but it was significantly suppressed in plots having received azoxystrobin or pyraclostrobin, regardless of the cultivar type or fertility regime. Therefore, to prevent unnecessary N inputs, growers need to supply only the necessary N amount to optimize tuber yields and manage early blight with fungicides.L’alternariose, causée par Alternaria solani, est une maladie omniprésente qui peut réduire le rendement de la pomme de terre. Une fertilisation adéquate de la culture et l’application de fongicides appropriés suppriment généralement le développement de cette maladie. Des essais en champs ont été effectués à l’Île-du-Prince-Édouard pour déterminer si des analogues de la strobilurine, notamment l’azoxystrobine et la pyraclostrobine, pouvaient supprimer l’alternariose de la pomme de terre (cv. Shepody et Russet Burbank) cultivée sous deux régimes de fertilité azotée (forte et faible doses de N). L’azoxystrobine et la pyraclostrobine ont été associées au rendement total en tubercules significativement supérieur pour Russet Burbank en 2003 et pour Shepody en 2004, comparativement à des parcelles n’ayant reçu aucun fongicide apparenté à la strobilurine. La fertilité azotée n’a entraîné aucune différence significative du rendement, bien que la dose élevée d’azote ait significativement réduit la maladie dans les parcelles témoins de Russet Burbank en 2004. En raison de l’absence de l’alternariose en 2003, l’augmentation du rendement du cv. Russet Burbank peut être attribuée aux modifications causées par les produits de la strobilurine dans la physiologie et le développement des plantes traitées. En 2004, l’alternariose a été importante dans les parcelles témoins inoculées, mais la suppression a été significative dans les parcelles ayant reçu de l’azoxystrobine ou de la pyraclostrobine, quels que soient le cultivar ou le régime de fertilité. Ainsi, les producteurs devraient appliquer uniquement les quantités d’azote nécessaires pour optimiser les rendements en tubercules et contrôler l’alternariose avec des fongicides
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Degradation of contaminants of emerging concern by UV/H2O2 for water reuse: Kinetics, mechanisms, and cytotoxicity analysis.
Advanced oxidation using UV and hydrogen peroxide (UV/H2O2) has been widely applied to degrade contaminants of emerging concern (CECs) in wastewater for water reuse. This study investigated the degradation kinetics of mixed CECs by UV/H2O2 under variable H2O2 doses, including bisphenol A, estrone, diclofenac, ibuprofen, and triclosan. Reverse osmosis (RO) treated water samples from Orange County Water District's Groundwater Replenishment System (GWRS) potable reuse project were collected on different dates and utilized as reaction matrices with spiked additions of chemicals (CECs and H2O2) to assess the application of UV/H2O2. Possible degradation pathways of selected CECs were proposed based on high resolution mass spectrometry identification of transformation products (TPs). Toxicity assessments included cytotoxicity, aryl hydrocarbon receptor-binding activity, and estrogen receptor-binding activity, in order to evaluate potential environmental impacts resulting from CEC degradation by UV/H2O2. Cytotoxicity and estrogenic activity were significantly reduced during the degradation of mixed CECs in Milli-Q water by UV/H2O2 with high UV fluence (3200 mJ cm-2). However, in GWRS RO-treated water samples collected in April 2017, the cytotoxicity and estrogen activity of spiked CEC-mixture after UV/H2O2 treatment were not significantly eliminated; this might be due to the high concentration of target CEC and their TPs, which was possibly affected by the varied quality of the secondary treatment influent at this facility such as sewer-shed and wastewater discharges. This study aimed to provide insight on the impacts of post-UV/H2O2 CECs and TPs on human and ecological health at cellular level
Fluctuations and scaling in creep deformation
The spatial fluctuations of deformation are studied in creep in the Andrade's
power-law and the logarithmic phases, using paper samples. Measurements by the
Digital Image Correlation technique show that the relative strength of the
strain rate fluctuations increases with time, in both creep regimes. In the
Andrade creep phase characterized by a power law decay of the strain rate
, with , the fluctuations obey
, with . The local
deformation follows a data collapse appropriate for an absorbing
state/depinning transition. Similar behavior is found in a crystal plasticity
model, with a jamming or yielding phase transition
Preparing for a Northwest Passage: A Workshop on the Role of New England in Navigating the New Arctic
Preparing for a Northwest Passage: A Workshop on the Role of New England in Navigating the New Arctic (March 25 - 27, 2018 -- The University of New Hampshire) paired two of NSF\u27s 10 Big Ideas: Navigating the New Arctic and Growing Convergence Research at NSF. During this event, participants assessed economic, environmental, and social impacts of Arctic change on New England and established convergence research initiatives to prepare for, adapt to, and respond to these effects. Shipping routes through an ice-free Northwest Passage in combination with modifications to ocean circulation and regional climate patterns linked to Arctic ice melt will affect trade, fisheries, tourism, coastal ecology, air and water quality, animal migration, and demographics not only in the Arctic but also in lower latitude coastal regions such as New England. With profound changes on the horizon, this is a critical opportunity for New England to prepare for uncertain yet inevitable economic and environmental impacts of Arctic change
Unlike particle correlations and the strange quark matter distillation process
We present a new technique for observing the strange quark matter
distillation process based on unlike particle correlations. A simulation is
presented based on the scenario of a two-phase thermodynamical evolution model.Comment: 15 pages, 2 figures, 1 tabl
The fast and furious
Cocaine and amphetamines (‘stimulants’) are distinct central nervous system stimulants with similar effects (Pleuvry, 2009; Holman, 1994). Cocaine is a crystalline tropane alkaloid extracted from coca leaves. Amphetamines are a subclass of phenylethylamines with primarily stimulant effects, including amphetamine, methamphetamine, methcathinone and cathinone and referred to as ‘amphetamines’ in this review (Holman, 1994). MDMA (3,4-methylenedioxy-N-methamphetamine or ecstasy) is a substituted amphetamine known for its entactogenic, psychedelic, and stimulant effects (Morgan, 2000). Stimulants can produce increased wakefulness, focus and confidence, elevated mood, feelings of power, and decreased fatigue and appetite; stimulants also produce nervousness or anxiety and, in some cases, psychosis and suicidal thoughts (Holman, 1994; EMCDDA, 2007f; Hildrey et al., 2009; Pates and Riley, 2009). Although there is little evidence that stimulants cause physical dependence, tolerance may develop upon repetitive use and withdrawal may cause discomfort and depression (EMCDDA, 2007f; Pates and Riley, 2009). Users may engage in ‘coke or speed binges’ alternated with periods of withdrawal and abstinence (Beek et al., 2001)
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