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1
Batson, William G., Iain J. Gordon, Donald B. Fletcher et Adrian D. Manning. « The effect of pre-release captivity on post-release performance in reintroduced eastern bettongs Bettongia gaimardi ». Oryx 50, no 4 (11 août 2015) : 664–73. http://dx.doi.org/10.1017/s0030605315000496.
Résumé :
AbstractReintroductions are used to re-establish populations of species within their indigenous range, but their outcomes are variable. A key decision when developing a reintroduction strategy is whether to include a temporary period of confinement prior to release. Pre-release confinement is primarily used for the purpose of quarantine or as a delayed-release tactic to influence the performance or behaviour of founders post-release. A common difference between these approaches is that quarantine tends to be conducted in ex situ captivity, whereas delayed releases tend to involve in situ confinement at the release site. Although these practices are commonly viewed independently, it may be possible for a single confinement period to be used for both purposes. We tested whether temporarily holding wild eastern bettongs Bettongia gaimardi in ex situ captivity for 95–345 days prior to release (delayed release) influenced their body mass, pouch occupancy or survival during the first 1.5 years post-release, compared to founders released without confinement (immediate release). Our results suggest that exposing founders to captivity did not alter their body mass or performance post-release, despite being heavier and having fewer pouch young when released. We conclude that, for this species, ex situ captivity does not represent a tactical opportunity to improve post-release performance but can be used for quarantine without affecting the probability of establishment.
2
Van der Kloot, W., et J. Molgo. « Facilitation and delayed release at about 0 degree C at the frog neuromuscular junction : effects of calcium chelators, calcium transport inhibitors, and okadaic acid ». Journal of Neurophysiology 69, no 3 (1 mars 1993) : 717–29. http://dx.doi.org/10.1152/jn.1993.69.3.717.
Résumé :
1. We studied two-pulse facilitation and delayed release at 0 degree C, because at low temperature facilitation is enhanced and extended whereas delayed release is increased. Our major goal was to test, by a number of approaches, the residual Ca2+ hypothesis of facilitation and delayed release. 2. As we increased the interval between pulses from 30 to 100–200 ms facilitation declined steeply. As we lengthened the interval further facilitation declined more slowly. In our entire series facilitation was still seen at 700 ms, in some preparations facilitation was apparent at 2 s. 3. We measured delayed release in preparations in which excitation-contraction was uncoupled. The decline in the rate of delayed release following the endplate potential (EPP) is similar to the decay of facilitation, both at 0 and 22 degrees C. 4. When we replaced the Ca2+ in the Ringer by Sr2+, facilitation persisted for a longer time, there was significant facilitation 2 s after an EPP. Delayed release also continued longer; the time courses for the decline of facilitation and delayed release were very similar. 5. We measured delayed release after EPPs triggered by electrotonic depolarization in isotonic CaCl2 solution or in Ringer in which the Na+ was replaced by methylamine (these solutions also contained 3,4-diaminopyridine). The time course of delayed release was very similar to that in Ringer. 6. We found that delayed release also facilitated, in the sense that the number of delayed releases, and the rate at which they were released, increased markedly after a second or third closely spaced EPP. The facilitation of delayed release and of EPPs were quantitatively similar. 7. We soaked preparations for 2 h in 200 microM bis-(aminophenoxy) ethane-tetraacetic acid (BAPTA/AM), a cell permeable Ca2+ chelator. In about one-half of these preparations facilitation was clearly diminished, judging from the EPPs evoked by a series of four to five stimuli at 30-ms intervals. The summed results from those preparations in which facilitation was reduced at 30 ms showed that it was also reduced at longer intervals. There was a comparable shortening in delayed release. Facilitation was significantly reduced when we pretreated with ethylene glycol bis-(beta-aminoethyl ether) N,N,N',N'-tetraacetic acid tetraacetoxymethyl ester (EGTA/AM), another cell-permeable Ca2+ chelator. 8. It has been reported that in BAPTA loaded preparations facilitation during trains of EPPs transiently reappears after exposure to the ionophore X-537A, which presumably elevates intracellular [Ca2+].(ABSTRACT TRUNCATED AT 400 WORDS)
3
Chuhma, Nao, et Harunori Ohmori. « Role of Ca2+ in the Synchronization of Transmitter Release at Calyceal Synapses in the Auditory System of Rat ». Journal of Neurophysiology 87, no 1 (1 janvier 2002) : 222–28. http://dx.doi.org/10.1152/jn.00235.2001.
Résumé :
The synchronization of transmitter release in the synapse of the medial nucleus of the trapezoid body (MNTB) is achieved during early postnatal development as a consequence of elimination of delayed asynchronous releases and appears to reflect changes in the dynamics of Ca2+ entry and clearance. To examine the role of Ca2+ in regulating synchronization of transmitter release in the mature synapse (after postnatal day 9, P9), we perturbed Ca2+ dynamics systematically. Replacement of external Ca2+ (2 mM) with Sr2+ induced delayed asynchronous release following the major EPSC. We tried to reproduce asynchronous releases without using Sr2+ and instead by manipulating the time course and the size of Ca2+ transient in the presynaptic terminal, under the assumption that replacement of external Na+ with Li+ or application of eosin-Y would prolong the lifetime of Ca2+ transient by reducing the rate of Ca2+ extrusion from the terminal. With application of Li+, Ca2+ transient in the terminal was prolonged, the EPSC decay time course was prolonged, and the EPSC amplitude increased. However, these EPSCs were not followed by delayed asynchronous release. When Ca2+ influx was reduced, either by partial Ca2+ channel blockade with a low concentration of Cd2+ or ω-agatoxin IVA, a marked asynchronous release resulted. This was further enhanced by the combined application of Li+ or eosin-Y. These results suggest that cooperative increases of both Ca2+ influx and Ca2+ clearance capacities leading to a sharper Ca2+ spike in the presynaptic terminal underlie synchronized transmitter release in the presynaptic terminal of the MNTB.
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Vafaie, Erfan K., H. Brent Pemberton, Mengmeng Gu, David Kerns, Micky D. Eubanks et Kevin M. Heinz. « Adding a Natural Enemy to Respond to Pest Immigration and Delayed Natural Enemy Releases in Augmentative Biological Control ». Environmental Entomology 50, no 3 (2 avril 2021) : 561–70. http://dx.doi.org/10.1093/ee/nvab007.
Résumé :
Abstract Whether increased natural enemy density or adding a second natural enemy species will provide superior pest suppression in greenhouse augmentative biological control is unknown for many commercially available natural enemy species. In this study, we use sweetpotato whiteflies, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), on poinsettias, Euphorbia pulcherrima Willd. ex Klotzsch (Malpighiales: Euphorbiaceae), to determine whether adding Amblyseius swirskii (Athias-Henriot) (Acari: Phytoseiidae) to Eretmocerus eremicus Rose and Zolnerowich (Hymenoptera: Aphelinidae) is better for B. tabaci suppression compared with either natural enemy alone, both with and without challenges with whitefly immigration or delayed natural enemy releases. The number of whiteflies on caged poinsettias treated with different natural enemy release rates (single or double rate), natural enemy species (one or two species), natural enemy delayed release (weeks 4 and 8), and whitefly immigration treatments (introduced at week 4 or week 8) was censused biweekly for 16 wk. Both species used in combination provided similar or better suppression of whiteflies compared with either natural enemy alone. Both species combined also provided superior suppression of whiteflies when challenged with whitefly immigration or delays in natural enemy releases compared with E. eremicus alone. Whitefly immigration or delays in E. eremicus releases did not increase whitefly populations, suggesting that suppression of whiteflies by E. eremicus alone is relatively robust. This study found no evidence for negative interactions between E. eremicus and A. swirskii for suppressing B. tabaci.
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Eden, T. M., P. J. Gerard, J. J. Dymock et N. Ahmad. « Investigation into the delayed establishment of Microctonus aethiopoides in Northland ». New Zealand Plant Protection 62 (1 août 2009) : 414. http://dx.doi.org/10.30843/nzpp.2009.62.4868.
Résumé :
The Irish strain of Microctonus aethiopoides was released in New Zealand in 2006 to help control clover root weevil (Sitona lepidus) Establishment was rapid at all release sites except in Northland where multiple releases appeared to fail until low numbers were recovered in 2008 It was hypothesised that because Northland at 35S is at sufficiently different latitude to the original collection sites near Belfast Ireland (5437N) there is a crossing of the critical photoperiod for diapause induction in the wasp larvae Replicated cage trials were undertaken to compare the prevalence of premature diapause in Northland with Waikato under natural daylength and simulated Far North midsummer photoperiod (1410 h light dark) with a 16 h photoperiod Results indicated that larval diapause inside the weevil may be initiated by the parent wasp as significantly more 1st instar larvae were present in weevils where wasps had been subjected to reducing daylength (16 h down to 14 h light) High mortality amongst singlylaid wasp larvae in the Northland summer and the absence of teratocytes usually associated with larvae indicates clover root weevil adults can defeat a singlylaid parasitoid These results may explain the reduced efficacy of the Irish wasp in Northland
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Zamyadi, Arash, Katherine E. Greenstein, Caitlin M. Glover, Craig Adams, Erik Rosenfeldt et Eric C. Wert. « Impact of Hydrogen Peroxide and Copper Sulfate on the Delayed Release of Microcystin ». Water 12, no 4 (13 avril 2020) : 1105. http://dx.doi.org/10.3390/w12041105.
Résumé :
Algicides, like hydrogen peroxide and copper sulfate, are commonly applied to recreational waters and drinking water sources to mitigate cyanobacterial blooms. In this work, the effects of hydrogen peroxide and copper sulfate were evaluated in two natural bloom samples (collected from Canadian and American waterbodies) and one lab-cultured Microcystis aeruginosa suspended in Colorado River water. Five algicide to dissolved organic carbon (DOC) dose ratios were evaluated during an initial exposure period of 24 h. One dose ratio (0.4 H2O2:DOC or 0.25 CuSO4:DOC) was then evaluated during stagnation after quenching (hydrogen peroxide) or extended exposure (copper sulfate) for up to 96 or 168 h. During the initial hydrogen peroxide exposure, the CA bloom had no release of intracellular microcystins (MCs) and the USA bloom only released MC at 4 H2O2:DOC. The reverse occurred with copper sulfate, where the CA bloom released MCs at 0.6 CuSO4:DOC but the USA bloom had no detectable extracellular MCs. Extracellular MC was released from the lab-cultured Microcystis at the lowest hydrogen peroxide and copper sulfate doses. In the hydrogen peroxide stagnation experiment, intracellular MC decreased in the USA bloom after 168 h despite the low dose applied. Similarly, the extended copper sulfate exposure led to intracellular MC decreases in both bloom samples after 168 h, despite showing no impact during the initial 24 h monitoring period. The lab-cultured Microcystis was again less resistant to both algicides, with releases observed after less than 2 h of stagnation or exposure. The damage to cells as measured by pigments during these experiments did not match the MC data, indicating that blooms with depressed pigment levels can still be a risk to nearby drinking water sources or recreational activities. These results provide insight on the timeline (up to one week) required for monitoring the potential release of MCs after algicide application.
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Steelman, Samantha M., Travis W. Hein, Amy Gorman et Gregory J. Bix. « Effects of Histidine-Rich Glycoprotein on Cerebral Blood Vessels ». Journal of Cerebral Blood Flow & ; Metabolism 33, no 9 (26 juin 2013) : 1373–75. http://dx.doi.org/10.1038/jcbfm.2013.106.
Résumé :
Delayed cerebral vasospasm is thought to be caused by factors released from a subarachnoid blood clot. Because vasospasm occurs several days after hemorrhage, we hypothesized that clotted blood releases vasoactive factors as it ages. Targeted proteomics identified histidine-rich glycoprotein (HRG) as a potentially vasoactive factor released within the first 72 hours of clot formation. In vitro studies revealed that HRG caused moderate (~30%) dilation of cannulated cerebral arterioles and proliferation of cerebrovascular endothelial cells. We conclude that HRG released from clotted blood, while unlikely to contribute to cerebral vasospasm, might provide important vasodilatory or angiogenic stimuli after hemorrhagic stroke.
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Alderman, Stephen C., Darrin L. Walenta, Philip B. Hamm, Ruth C. Martin, Jeremiah Dung et Evsey Kosman. « Afternoon Ascospore Release in Claviceps purpurea Optimizes Perennial Ryegrass Infection ». Plant Disease 99, no 10 (octobre 2015) : 1410–15. http://dx.doi.org/10.1094/pdis-09-14-0978-re.
Résumé :
In Kentucky bluegrass (Poa pratensis), Claviceps purpurea, the causal agent of ergot, typically releases ascospores during the early-morning hours, between about midnight and 10:00 a.m., corresponding to time of flowering, when the unfertilized ovaries are most susceptible to infection. During aeromycology studies of C. purpurea in perennial ryegrass (Lolium perenne) in northeastern Oregon during 2008 to 2010 and 2013, a strain of C. purpurea was found that released ascospores in the afternoon, coinciding with flowering in perennial ryegrass. Under controlled environmental conditions, sclerotia from perennial ryegrass and Kentucky bluegrass released spores in the afternoon and morning, respectively, consistent with timing of spore release under field conditions. Internal transcribed spacer (ITS) sequences of single sclerotial isolates from Kentucky bluegrass and perennial ryegrass were consistent with C. purpurea, although minor variations in ITS sequences among isolates were noted. Differences between Kentucky bluegrass and perennial ryegrass isolates were observed in random amplified polymorphic DNA. Evidence is provided for adaptation of C. purpurea to perennial ryegrass by means of delayed spore release that coincides with afternoon flowering in perennial ryegrass.
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Supawat, Likittanawong, et Leemakdej Arnat. « Market Reaction to Corporate Releases and News Articles : Evidence from Thailand’s Stock Market ». International Journal of Financial Studies 11, no 3 (6 septembre 2023) : 111. http://dx.doi.org/10.3390/ijfs11030111.
Résumé :
Studies that quantify the price impact of the information in corporate press releases and news articles mainly focus on quantitative news, such as earnings announcements, dividends, and financial performance-related events, but leave out other corporate news events. Those that do so generally focus on one source of information and do not compare the price impacts from different information sources. Our study aimed to extend previous studies by quantifying and comparing market reactions to corporate press releases and news articles across different news categories. We classified and categorized 100,960 news items, encompassing 26,546 corporate press releases and 74,414 news articles, of 615 firms in the Stock Exchange of Thailand between 1 January 2017 and 31 December 2019. These news items were classified into categories based on the information contained in corporate press releases and news articles. We then studied the market reactions to these news categories. We found that the price impact from corporate releases is sustained for both positive and negative news categories. Our results also show that the positive price impact for news reported by the media tends to reverse, consistent with prior studies. In contrast, the negative price impact from news articles holds; this result differs from previous studies. Our data also show that managers tend to leak and recycle good news while the release of bad news is delayed.
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Kampawong, H., W. Utto et R. Pruthtikul. « Effects of relative humidity on ethanol vapour releases from hydrophilic filmbased sachet in active food packaging ». Food Research 5, no 5 (19 septembre 2021) : 89–94. http://dx.doi.org/10.26656/fr.2017.5(5).202.
Résumé :
Active food package incorporating an ethanol vapour-controlled release sachet has been known for its efficacies to delay microbial proliferation in fresh fruit and vegetable. High humidity inside the package could be utilized as a stimulus for conditional releases as a means to stabilize the sachet prior to being used. The present research was undertaken to investigate the effects of relative humidity on ethanol vapour release from the hydrophilic film-based sachet. The prototype 4-side sealed sachets were made of either ethylene vinyl acetate (EVA) or laminated film comprising EVA and Nylon/PE (designated as ENP). A gas chromatogram equipped with a flame-ionized detector (FID-GC) was employed to analyze ethanol vapour concentration levels released from both sachet types and accumulated in headspaces of sealed glass beakers having different relative humidity (RH) levels. For a given RH level, the concentrations in the headspaces containing the ENPbased sachets were lower than those containing the EVA-based sachets. Delays of ethanol vapour release up to 24 h were observed in the ENP-based sachet system, whilst these did not occur among EVA-based sachets. Both sachets could release ethanol vapour with faster rates and subsequently higher concentrations accumulated at the very high relative humidity level (90-99% RH), compared to lower RH levels (60-89% RH). However, the release rates and concentration levels accumulated in 60-75% RH were not different from those in 80-89% RH. Extents of water vapour uptake by films were relatively small when the films were kept at the lower RH levels, but these became exponentially increased when the RH levels were ≥90%RH. Experimental data on water vapour uptakes were well predicted by an exponential model (R2 0.92-0.99; and root mean square of errors (RMSE) 0.004-0.054). Overall, experiment findings indicate that the ENP film caused delayed ethanol vapour releases from the sachet. The relative humidity levels had significant effects on the releases from hydrophilic film-based sachets
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CARLSSON, ANJA M., KENNETH WILSON et R. JUSTIN IRVINE. « Development and application of a delayed-release anthelmintic intra-ruminal bolus system for experimental manipulation of nematode worm burdens ». Parasitology 139, no 8 (15 mars 2012) : 1086–92. http://dx.doi.org/10.1017/s0031182012000406.
Résumé :
SUMMARYIn order to quantify the impact of parasites on host population dynamics, experimental manipulations that perturb the parasite-host relationship are needed but, logistically, this is difficult for wild hosts. Here, we describe the use of a delayed-release anthelmintic delivery system that can be administered when the hosts can be captured and its activity delayed until a more appropriate period in the host-parasite cycle. Our model system is Svalbard reindeer infected with a nematode parasite, Marshallagia marshalli, which appears to accumulate during the Arctic winter. To determine the extent to which this occurs and the effect on host fitness, reindeer need to be treated with anthelmintics in late autumn but they can only be caught and handled in April. To solve this problem, we devised an intra-ruminal capsule that releases the anthelmintic from up to 6 months after being administered. The capsule was trialed in cannulated sheep and red deer to determine optimum capsule orifice size and release rates. Capsules were estimated to release placebo for 100–153 days followed by abamectin for 22–34 days. To test the efficacy of treatment in reindeer, capsules were administered in April and retrieved in October. All capsules had fully released the anthelmintic and treated reindeer had significantly lower worm burdens than controls. Thus, success of this system allows repeated treatment over several years to test the effect of winter parasitism on host fitness.
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Hijazi, Nuha, Rami Abu Fanne, Rinat Abramovitch, Serge Yarovoi, Muhamed Higazi, Suhair Abdeen, Maamon Basheer, Emad Maraga, Douglas B. Cines et Abd Al-Roof Higazi. « Endogenous plasminogen activators mediate progressive intracerebral hemorrhage after traumatic brain injury in mice ». Blood 125, no 16 (16 avril 2015) : 2558–67. http://dx.doi.org/10.1182/blood-2014-08-588442.
Résumé :
Key Points Closed head trauma sequentially releases tPA followed by uPA from injured brain. Increased uPA is responsible for delayed intracerebral hemorrhage, which is prevented by a tPA variant that inhibits uPA activity.
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Le Fessant, Elouan, Anne-Cécile Gregoire, Nicolas Nuns, Pardis Simon, Anne-Sophie Mamede, Jean-François Paul et Laurent Cantrel. « ToF-SIMS and XPS characterizations of model fission products (I, Cs) deposits after thermal treatment simulating late phase conditions of a nuclear power plant severe accident ». EPJ Web of Conferences 273 (2022) : 01004. http://dx.doi.org/10.1051/epjconf/202227301004.
Résumé :
During a Severe Accident (SA) occurring in a nuclear power plant, many Fission Products (FP) are released from the degraded fuel and are transported in the Reactor Coolant System (RCS). Depending on their volatility, FP can be either deposited on the surface of the Reactor Coolant System (RCS) or transported into the containment building from where they may be released into the environment in case of early containment failure. This was the case for the Fukushima Daiichi (FD) accident with important FP releases which were observed following the containment vessel failure which lasted up to several weeks after the accident. If early phase releases were well predicted by SA simulation codes, delayed releases were not correctly predicted [1]. Such discrepancies can be attributed to the revaporization of deposits inside the RCS which were not yet modeled in the SA simulation tools. Previous experiments over the past 20 years evidenced the possible formation and revaporization of CsI [2]. However, up to now, no clear CsI revaporization mechanism has been determined. In order to propose a mechanism, this study (scheduled within the OECD/NEA/ESTER project) aims at determining the speciation of each species remaining on the substrate after revaporization tests under different conditions using XPS and ToF-SIMS (X-ray Photoelectron Spectroscopy and Time of Flight Secondary Ion Mass Spectrometry. These two combined techniques allow the identification of the main species of the residue leading to the proposition of two revaporization reactions.
14
Treese, Daniel P., Shirley E. Clark et Katherine H. Baker. « Nutrient Release from Disturbance of Infiltration System Soils during Construction ». Advances in Civil Engineering 2012 (2012) : 1–7. http://dx.doi.org/10.1155/2012/393164.
Résumé :
Subsurface infiltration and surface bioretention systems composed of engineered and/or native soils are preferred tools for stormwater management. However, the disturbance of native soils, especially during the process of adding amendments to improve infiltration rates and pollutant removal, may result in releases of nutrients in the early life of these systems. This project investigated the nutrient release from two soils, one disturbed and one undisturbed. The disturbed soil was collected intact, but had to be air-dried, and the columns repacked when soil shrinkage caused bypassing of water along the walls of the column. The undisturbed soil was collected and used intact, with no repacking. The disturbed soil showed elevated releases of nitrogen and phosphorus compared to the undisturbed soil for approximately 0.4 and 0.8 m of runoff loading, respectively. For the undisturbed soil, the nitrogen release was delayed, indicating that the soil disturbance accelerated the release of nitrogen into a very short time period. Leaving the soil undisturbed resulted in lower but still elevated effluent nitrogen concentrations over a longer period of time. For phosphorus, these results confirm prior research which demonstrated that the soil, if shown to be phosphorus-deficient during fertility testing, can remove phosphorus from runoff even when disturbed.
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Spencer, C. Ian, et James S. K. Sham. « Effects of Na+/Ca2+ exchange induced by SR Ca2+ release on action potentials and afterdepolarizations in guinea pig ventricular myocytes ». American Journal of Physiology-Heart and Circulatory Physiology 285, no 6 (décembre 2003) : H2552—H2562. http://dx.doi.org/10.1152/ajpheart.00274.2003.
Résumé :
In cardiac cells, evoked Ca2+ releases or spontaneous Ca2+ waves activate the inward Na+/Ca2+ exchange current ( INaCa), which may modulate membrane excitability and arrhythmogenesis. In this study, we examined changes in membrane potential due to INaCa elicited by sarcoplasmic reticulum (SR) Ca2+ release in guinea pig ventricular myocytes using whole cell current clamp, fluorescence, and confocal microscopy. Inhibition of INaCa by Na+-free, Li+-containing Tyrode solution reversibly abbreviated the action potential duration at 90% repolarization (APD90) by 50% and caused SR Ca2+ overload. APD90 was similarly abbreviated in myocytes exposed to the Na+/Ca2+ exchange inhibitor KB-R7943 (5 μM) or after inhibition of SR Ca2+ release with ryanodine (20 μM). In the absence of extracellular Na+, spontaneous SR Ca2+ releases caused minimal changes in resting membrane potential. After the myocytes were returned to Na+-containing solution, the potentiated intracellular Ca2+ concentration ([Ca2+]i) transients dramatically prolonged APD90 and [Ca2+]i oscillations caused delayed and early afterdepolarizations (DADs and EADs). Laser-flash photolysis of caged Ca2+ mimicked the effects of spontaneous [Ca2+]i oscillations, confirming that APD prolongation, DADs, and EADs could be ascribed to intracellular Ca2+ release. These results suggest that Na+/Ca2+ exchange is a major physiological determinant of APD and that INaCa activation by spontaneous SR Ca2+ release/oscillations, depending on the timing, can account for both DADs and EADs during SR Ca2+ overload.
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Wang, Yubao, Pei Yu, Yi Li, Zhan Zhao, Xiaomei Wu, Lu Zhang, Jing Feng et Jau-Shyong Hong. « Early-Released Interleukin-10 Significantly Inhibits Lipopolysaccharide-Elicited Neuroinflammation In Vitro ». Cells 10, no 9 (24 août 2021) : 2173. http://dx.doi.org/10.3390/cells10092173.
Résumé :
Anti-inflammatory cytokine interleukin (IL)-10 is pivotal for limiting excessive inflammation in the central nervous system. Reports show that lipopolysaccharide (LPS)-induced microglial IL-10 emerges in a delayed manner in vitro and in vivo, lagging behind proinflammatory cytokines to facilitate the resolution of neuroinflammation. We hypothesized that IL-10 releases quite quickly based on our pilot investigation. Here, we uncovered a bimodal expression of microglial IL-10 gene transcription induced by LPS in mouse primary mixed glial cultures. This pattern consisted of a short brief early-phase and a long-lived late-phase, enabling the production of IL-10 protein in a rapid manner. The removal and addition of IL-10 protein assays indicated that early-released IL-10 exerted potent modulatory effects on neuroinflammation at picomolar levels, and IL-10 released at the onset of neuroinflammation is tightly controlled. We further showed that the early-released, but not the late-released, IL-10 was crucial for mediating and potentiating the anti-inflammatory function of a β2-adrenergic receptor agonist salmeterol. This study in vitro highlights the essential role of early-released IL-10 in regulating the appropriate degree of neuroinflammation, overturning the previous notion that microglial IL-10 produces and functions in a delayed manner and providing new insights into anti-inflammatory mechanisms-mediated neuroimmune homeostasis.
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Boyden, Penelope A., Wen Dun et Bruno D. Stuyvers. « What is a Ca2+ wave ? Is it like an Electrical Wave ? » Arrhythmia & ; Electrophysiology Review 4, no 1 (2015) : 35. http://dx.doi.org/10.15420/aer.2015.4.1.35.
Résumé :
Arrhythmia subcellular mechanisms are constantly being explored. Recent knowledge has shown that travelling Ca2+waves in cardiac cells are critical for delayed afterdepolarisations and in some cases, early afterdepolarisations. In this review, we comment on the properties of cardiac Ca2+waves and abnormal Ca2+releases in terms of properties used to describe electrical waves; propagation, excitability and refractoriness.
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Dechow, Patricia M., Alastair Lawrence et James P. Ryans. « SEC Comment Letters and Insider Sales ». Accounting Review 91, no 2 (1 juillet 2015) : 401–39. http://dx.doi.org/10.2308/accr-51232.
Résumé :
ABSTRACT We document that insider trading is significantly higher than normal levels prior to the public disclosure of SEC comment letters relating to revenue recognition. Furthermore, insider trading is triple its normal level for firms with high short positions. We find a small negative return at the comment letter release date and a negative drift in returns of 1 to 5 percent over the next 50 days following the release. We also find that greater pre-disclosure sales are associated with a stronger negative drift. This evidence suggests that insiders appear to benefit from trading prior to revenue recognition comment letters. We investigate whether the delayed price reaction to comment letter releases is due to investor inattention. Consistent with this explanation, we document that comment letters are downloaded infrequently from EDGAR in the days following their public disclosure. JEL Classifications: M41; M48; K42
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Boels, P. J., V. A. Claes et D. L. Brutsaert. « Mechanics of K(+)-induced isotonic and isometric contractions in isolated canine coronary microarteries ». American Journal of Physiology-Cell Physiology 258, no 3 (1 mars 1990) : C512—C523. http://dx.doi.org/10.1152/ajpcell.1990.258.3.c512.
Résumé :
The effects of shortening in isotonic contractions on the mechanics of microvascular smooth muscle were investigated. Intramyocardial canine coronary microarteries (in situ diameter 60 +/- 3 microns) were mounted as rings, connected to a newly developed photoelectromagnetic force-length transducer, and activated with 125 mM K+. Shortening during isotonic contractions depressed the length-force relation (shortening deactivation) compared with the length-force relation obtained from isometric contractions; the effect was present at the earliest moments after activation, suggesting that a fundamental mechanism associated with the actual sliding of contractile filaments delayed onset of contractile activity in isotonic contractions compared with isometric contractions. Force-velocity relations were obtained by isotonic quick releases from isotonic and isometric contractions at various times. Isotonic shortening before the quick releases reduced the constants of the apparent hyperbolic force-velocity relations and maximal velocity of shortening (Vmax) compared with isometric contractions released at the same time. Increasing contraction duration reduced Vmax but more so in isotonic than in isometric contractions. Vmax also decreased with decreasing instantaneous length. A possible effect of force development on Vmax before the isotonic quick release was also described. Quick increments of load during isotonic contractions were sustained during active shortening in the phasic part, but during the tonic part loading resulted in a pronounced transient relaxation. Thus, in microvascular preparations, active isotonic shortening altered the length-force, force-velocity, and velocity-time relations and uncovered a time-dependent sensitivity to loading conditions. These experiments suggested that the mechanics of smooth muscle contraction may contribute significantly to the mechanisms of the physiological control of coronary microvascular diameter.
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Kalinowski, Martin B. « Characterisation of prompt and delayed atmospheric radioactivity releases from underground nuclear tests at Nevada as a function of release time ». Journal of Environmental Radioactivity 102, no 9 (septembre 2011) : 824–36. http://dx.doi.org/10.1016/j.jenvrad.2011.05.006.
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Maguire, Douglas A., Douglas B. Mainwaring, Robin Rose, Sean M. Garber et Eric J. Dinger. « Response of coastal Douglas-fir and competing vegetation to repeated and delayed weed control treatments during early plantation development ». Canadian Journal of Forest Research 39, no 6 (juin 2009) : 1208–19. http://dx.doi.org/10.1139/x09-032.
Résumé :
A key silvicultural decision in managing young conifer plantations is determining the number and timing of release treatments to control competing vegetation. Three coastal Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco) plantations were treated under eight alternative herbicide regimes during the first 5 years after planting to test treatment effects on vegetation dynamics and seedling growth. After termination of herbicide treatments, competing vegetation developed at a rate similar to that of check plots, reaching 40%–60% cover in the first growing season and approaching 100% by the third. Recovery of competing vegetation was slightly more rapid with greater number of previous releases. Annual volume growth of seedlings was negatively correlated with current cover of competing vegetation, but competitive effects from previous years were fully accounted for by initial tree size. Under 4 years of release, delaying treatment by 1 year reduced volume attained at the end of 5 years by about 15%. Plots receiving 5 consecutive years of weed control reached the 5 year volume of check plots in only 3.9 years, implying an age shift of 1.1 years. Increasing the number of operational release treatments significantly improved seedling growth in the short term, but long-term growth effects must be monitored to determine the economically optimal regime.
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Railsback, Steven F., Bret C. Harvey, Sarah J. Kupferberg, Margaret M. Lang, Scott McBain et Hart H. Welsh. « Modeling potential river management conflicts between frogs and salmonids ». Canadian Journal of Fisheries and Aquatic Sciences 73, no 5 (mai 2016) : 773–84. http://dx.doi.org/10.1139/cjfas-2015-0267.
Résumé :
Management of regulated rivers for yellow-legged frogs (Rana boylii) and salmonids exemplifies potential conflicts among species adapted to different parts of the natural flow and temperature regimes. Yellow-legged frogs oviposit in rivers in spring and depend on declining flows and warming temperatures for egg and tadpole survival and growth, whereas salmonid management can include high spring flows and low-temperature reservoir releases. We built a model of how flow and temperature affect frog breeding success. Its mechanisms include adults selecting oviposition sites to balance risks of egg dewatering by decreasing flow versus scouring by high flow, temperature effects on development, habitat selection by tadpoles, and mortality via dewatering and scouring. In simulations of a regulated river managed primarily for salmonids, below-natural temperatures delayed tadpole metamorphosis into froglets, which can reduce overwinter survival. However, mitigating this impact via higher temperatures was predicted to cause adults to oviposit before spring flow releases for salmonids, which then scoured the egg masses. The relative timing of frog oviposition and high flow releases appears critical in determining conflicts between salmonid and frog management.
23
Maslennikov, Serhii, Maxym Kozhemyaka et Maxym Golovakha. « SVF Therapy of Delayed Fracture Union in Patients with Multiple Combat Injury. Case Report ». Ortopedia Traumatologia Rehabilitacja 26, no 1 (29 février 2024) : 375–80. http://dx.doi.org/10.5604/01.3001.0054.4651.
Résumé :
Delayed union of fractures is one of the most frequent complications in orthopedic practice, especially in polytrauma patients. With the development of new methods of regenerative medicine, including the use of adipose derived stromal cells as a component of the stromal-vascular fraction (SVF), new possibilities for conservative treatment of this problem have emerged. This article presents a clinical case of conservative treatment of delayed union of a radial bone fracture using local SVF injections. In the fracture space, SVF with PRP creates a pool of cells that could differentiate towards surrounding tissue, releases various inducers of tissue growth and, via an indirect chemotactic effect on receptors, mobilizes the body’s own resources and creates conditions for angiogenesis and trophism in the injured segment. In the patient with delayed consolidation after SFV-therapy, progress in clinical and radiological dynamics was noted with complete healing within 7 months. The positive clinical result provides a basis for further study and implementation in practice.
24
Roberts, Paul C., Todd Kipperman et Richard W. Compans. « Vesicular Stomatitis Virus G Protein Acquires pH-Independent Fusion Activity during Transport in a Polarized Endometrial Cell Line ». Journal of Virology 73, no 12 (1 décembre 1999) : 10447–57. http://dx.doi.org/10.1128/jvi.73.12.10447-10457.1999.
Résumé :
ABSTRACT Entry of vesicular stomatitis virus (VSV), the prototype member of the rhabdovirus family, occurs by receptor-mediated endocytosis. Subsequently, during traversal through the endosomal compartments, the VSV G protein acquires a low-pH-induced fusion-competent form, allowing for fusion of the viral membrane with endosomal and lysosomal membranes. This fusion event releases genomic RNA into the cytoplasm of the cell. Here we provide evidence that the VSV G protein acquires a fusion-competent form during exocytosis in a polarized endometrial cell line, HEC-1A. VSV infection of HEC-1A cells results in high viral yields and giant cell formation. Syncytium formation is blocked in a concentration-dependent manner by treatment with the lysosomotropic weak base ammonium chloride, which raises intravesicular pH. Virus release is somewhat delayed by treatment with ammonium chloride, but virus yields gradually reach those of control cells. In addition, inhibition of vacuolar H+-ATPases by treatment with bafilomycin A1 also inhibited cell to cell fusion without altering virus yields. Virions released from infected HEC cells were themselves not fusion competent, since viral entry required an active H+-ATPase and a low-pH-induced conformational change in the viral G protein. Thus, the conformation change leading to fusion competence during exocytotic transport is reversible and reverts during or after release of the virion from the infected cell.
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Thead, Larry G., et Douglas A. Streett. « Duration of Pseudacteon curvatus Borgmeier (Diptera : Phoridae) Pupal Stages at Reduced Temperatures ». Journal of Entomological Science 41, no 2 (1 avril 2006) : 120–25. http://dx.doi.org/10.18474/0749-8004-41.2.120.
Résumé :
Duration times were determined for Pseudacteon curvatus Borgmeier pupae subjected to various temperature regimes. Pupae that had initially developed 12–15 d in parasitized fire ant, Solenopsis invicta Buren, workers held at ~27°C were collected and subsequently held at different temperature regimes. Pupae exposed to a temperature of 26.7°C had the earliest peak fly emergence 15 d later. Pupae exposed to a lower temperature of 18.3°C for 12 or 19 d and then exposed to a temperature of 26.7°C required an additional 7 and 11 d to peak fly emergence, respectively. At 18.3°C peak fly emergence was delayed an additional 20 d. At 10°C for 12 or 19 d followed by 26.7°C, peak fly emergence was delayed an additional 12 and 18 d, respectively. Holding pupae at 10°C for 54 d followed by 26.7°C delayed peak fly emergence by an additional 51 d with a correspondingly high mortality. Fly survival rates tended to decrease as peak emergence was delayed. Models that predict fly emergence when pupae are held at reduced temperatures will prove useful in rearing programs where extended storage of phorid fly pupae is necessary for optimizing releases.
26
Yoshida, Go, Tomohiko Hasegawa, Yu Yamato et Yukihiro Matsuyama. « Delayed neuromonitoring alarm after scoliosis correction in Lenke type 4 adolescent idiopathic scoliosis ». BMJ Case Reports 14, no 8 (août 2021) : e242289. http://dx.doi.org/10.1136/bcr-2021-242289.
Résumé :
A 12-year-old girl underwent surgery for Lenke type 4 adolescent idiopathic scoliosis. After scoliosis correction, the transcranial motor-evoked potential (Tc-MEP) showed no alarm. However, the Tc-MEP amplitude had declined ~10 min after correction, with a normal blood pressure (BP) and body temperature and without any technical monitoring errors. Therefore, we suspected indirect spinal cord ischaemia because of the delayed true-positive Tc-MEP alarm. All the strong corrections made loss of Tc-MEP and all the correction releases made recovers of waveform. Finally, a weak correction was performed, and the Tc-MEP amplitude was recovered. Because transient spinal cord ischaemia due to correction of triple curves may cause a delayed monitoring alarm, the monitoring team should frequently check Tc-MEP after these manoeuvres. This patient had no neurological deficits and was considered to be a rescue case.
27
Kooguchi, Kunihiko, Satoru Hashimoto, Atsuko Kobayashi, Yoshihiro Kitamura, Ichidai Kudoh, Jeanine Wiener-Kronish et Teiji Sawa. « Role of Alveolar Macrophages in Initiation and Regulation of Inflammation in Pseudomonas aeruginosaPneumonia ». Infection and Immunity 66, no 7 (1 juillet 1998) : 3164–69. http://dx.doi.org/10.1128/iai.66.7.3164-3169.1998.
Résumé :
ABSTRACT To evaluate the role of alveolar macrophages (AMs) in acutePseudomonas aeruginosa pneumonia in mice, AMs were depleted by aerosol inhalation of liposomes containing clodronate disodium. AM-depleted mice were then intratracheally infected with 5 × 105 CFU of P. aeruginosa. In addition to monitoring neutrophil recruitment and chemokine releases, lung injury was evaluated soon after infection (8 h) and at a later time (48 h). At 8 h, depletion of AMs reduced neutrophil recruitment, chemokine release, and lung injury. At 48 h, however, depletion of AMs decreased bacterial clearance and resulted in delayed movement of neutrophils from the site of inflammation with aggravated lung injury. With instillation of 5 × 107 CFU of bacteria, AM-depleted mice showed low mortality within 24 h of infection but high mortality at a later time, in contrast to non-AM-depleted mice. These results demonstrate that depletion of AMs has beneficial early effects but deleterious late effects on lung injury and survival in cases of P. aeruginosa pneumonia.
28
Nica, Cristina, Zhikai Lin, Anton Sculean et Maria B. Asparuhova. « Adsorption and Release of Growth Factors from Four Different Porcine-Derived Collagen Matrices ». Materials 13, no 11 (9 juin 2020) : 2635. http://dx.doi.org/10.3390/ma13112635.
Résumé :
Xenogeneic acellular collagen matrices represent a safe alternative to autologous soft tissue transplants in periodontology and implant dentistry. Here, we aimed to investigate the adsorption and release of growth factors from four porcine-derived collagen matrices using enzyme-linked immunosorbent assay. Non-crosslinked collagen matrix (NCM), crosslinked collagen matrix (CCM), dried acellular dermal matrix (DADM), and hydrated acellular dermal matrix (HADM) adsorbed each of the following growth factors, TGF-β1, FGF-2, PDGF-BB, GDF-5 and BMP-2, with an efficiency close to 100%. Growth factor release for a 13-day period was in the range of 10–50% of the adsorbed protein, except for the BMP-2 release that was in the range of 5–7%. Generally, protein release occurred in two phases. Phase I was arbitrary defined by the highest release from the matrices, usually within 24 h. Phase II, spanning the period immediately after the peak release until day 13, corresponded to the delayed release of the growth factors from the deeper layers of the matrices. HADM showed significantly (P < 0.001) higher TGF-β1, FGF-2, and PDGF-BB release in phase II, compared to the rest of the matrices. NCM exhibited significantly (P < 0.001) higher FGF-2 release in phase II, compared to CCM and DADM as well as a characteristic second peak in PDGF-BB release towards the middle of the tested period. In contrast to NCM and HADM, CCM and DADM showed a gradual and significantly higher release of GDF-5 in the second phase. Several burst releases of BMP-2 were characteristic for all matrices. The efficient adsorption and sustained protein release in the first 13 days, and the kinetics seen for HADM, with a burst release within hours and high amount of released growth factor within a secondary phase, may be beneficial for the long-term tissue regeneration following reconstructive periodontal surgery.
29
Roos, Juliana F., et Madhat Abdel-jawad. « Comparing hybrid method simulations to hydrogen dispersion and explosion tests ». Australian Energy Producers Journal 64, no 1 (16 mai 2024) : 258–65. http://dx.doi.org/10.1071/ep23206.
Résumé :
With an increase in the production and storage of hydrogen, it is likely that an increased number of explosions in which hydrogen plays a central role will occur unless a step change increase in safety is seen. Modelling releases of hydrogen and explosions arising from the delayed ignition of premixed gas clouds of hydrogen is carried out today using analytical and numerical approaches and most recently, using a hybrid methodology with the commercially available software exploCFD. Hybrid simulation methodology relies on the calculation of an analytically derived source term which is then used as an input for a 2D numerical simulation. In this paper we further our earlier validation work and test the ability of the hybrid methodology to predict flammable gas dispersion and subsequent explosions arising from hydrogen releases. Hydrogen has some particularly unique properties; it is the lightest of fuels – meaning masses involved are very small, and it has the highest laminar burning velocity – an order of magnitude greater than most hydrocarbons. The hybrid methodology is compared against previously documented 3D corner tests and dispersion tests. Excellent agreement between overpressure prediction and the reported experimental data for explosion against equivalence ratio is observed. The data from the hydrogen jet release simulations also compare extremely well to the previously reported experimental data. The results show that it is difficult to justify the use of far more laborious, time and cost-intensive purely numerical methods, or the use of largely uncertain more crude methods still widely used today.
30
Benoît, Hugues P., Connor W. Capizzano, Ryan J. Knotek, David B. Rudders, James A. Sulikowski, Micah J. Dean, William Hoffman, Douglas R. Zemeckis et John W. Mandelman. « A generalized model for longitudinal short- and long-term mortality data for commercial fishery discards and recreational fishery catch-and-releases ». ICES Journal of Marine Science 72, no 6 (11 mars 2015) : 1834–47. http://dx.doi.org/10.1093/icesjms/fsv039.
Résumé :
Abstract Conservation concerns and new management policies such as the implementation of ecosystem-based approaches to fisheries management are motivating an increasing need for estimates of mortality associated with commercial fishery discards and released fish from recreational fisheries. Traditional containment studies and emerging techniques using electronic tags on fish released to the wild are producing longitudinal mortality-time data from which discard or release mortalities can be estimated, but where there may also be a need to account analytically for other sources of mortality. In this study, we present theoretical and empirical arguments for a parametric mixture-distribution model for discard mortality data. We show, analytically and using case studies for Atlantic cod (Gadus morhua), American plaice (Hippoglossoides platessoides), and winter skate (Leucoraja ocellata), how this model can easily be generalized to incorporate different characteristics of discard mortality data such as distinct capture, post-release and natural mortalities, and delayed mortality onset. In simulations over a range of conditions, the model provided reliable parameter estimates for cases involving both discard and natural mortality. These results support this modelling approach, indicating that it is well suited for data from studies in which fish are released to their natural environment. The model was found to be less reliable in simulations when there was a delay in discard mortality onset, though such an effect appears only in a minority of existing discard mortality studies. Overall, the model provides a flexible framework in which to analyse discard mortality data and to produce reliable scientific advice on discard mortality rates and possibilities for mitigation.
31
Wiegers, Klaus, Gabriel Rutter, Hubert Kottler, Uwe Tessmer, Heinz Hohenberg et Hans-Georg Kräusslich. « Sequential Steps in Human Immunodeficiency Virus Particle Maturation Revealed by Alterations of Individual Gag Polyprotein Cleavage Sites ». Journal of Virology 72, no 4 (1 avril 1998) : 2846–54. http://dx.doi.org/10.1128/jvi.72.4.2846-2854.1998.
Résumé :
ABSTRACT Retroviruses are produced as immature particles containing structural polyproteins, which are subsequently cleaved by the viral proteinase (PR). Extracellular maturation leads to condensation of the spherical core to a capsid shell formed by the capsid (CA) protein, which encases the genomic RNA complexed with nucleocapsid (NC) proteins. CA and NC are separated by a short spacer peptide (spacer peptide 1 [SP1]) on the human immunodeficiency virus type 1 (HIV-1) Gag polyprotein and released by sequential PR-mediated cleavages. To assess the role of individual cleavages in maturation, we constructed point mutations abolishing cleavage at these sites, either alone or in combination. When all three sites between CA and NC were mutated, immature particles containing stable CA-NC were observed, with no apparent effect on other cleavages. Delayed maturation with irregular morphology of the ribonucleoprotein core was observed when cleavage of SP1 from NC was prevented. Blocking the release of SP1 from CA, on the other hand, yielded normal condensation of the ribonucleoprotein core but prevented capsid condensation. A thin, electron-dense layer near the viral membrane was observed in this case, and mutant capsids were significantly less stable against detergent treatment than wild-type HIV-1. We suggest that HIV maturation is a sequential process controlled by the rate of cleavage at individual sites. Initial rapid cleavage at the C terminus of SP1 releases the RNA-binding NC protein and leads to condensation of the ribonucleoprotein core. Subsequently, CA is separated from the membrane by cleavage between the matrix protein and CA, and late release of SP1 from CA is required for capsid condensation.
32
Miller, Benjamin E., Julie A. Coetzee et Martin P. Hill. « Mind the gap : the delayed recovery of a population of the biological control agent Megamelus scutellaris Berg. (Hemiptera : Delphacidae) on water hyacinth after winter ». Bulletin of Entomological Research 111, no 1 (27 août 2020) : 120–28. http://dx.doi.org/10.1017/s0007485320000516.
Résumé :
AbstractCold winter temperatures significantly affect the biological control effort against water hyacinth, Pontederia ( = Eichhornia) crassipes Mart. (Pontederiaceae), in more temperate regions around the world. The population dynamics of the planthopper Megamelus scutellaris Berg. (Hemiptera: Delphacidae), a newly released biological control agent of water hyacinth, were recorded on the Kubusi River in the Eastern Cape Province (South Africa) over 15 months to determine the population recovery post-winter. Megamelus scutellaris incurred a severe population decline at the onset of winter when the water hyacinth plants became frost damaged. The combined effect of a population bottleneck and low minimum winter temperatures (6.12°C) below the agent's lower developmental threshold (11.46°C) caused a post-winter lag in agent density increase. Subsequently, the maximum agent population density was only reached at the end of the following summer growing season which allowed the water hyacinth population to recover in the absence of any significant biological control immediately post-winter. Supplementary releases of agents from mass-reared cultures at the beginning of the growing season (spring) is suggested as a potential method of reducing the lag-period in field populations in colder areas where natural population recovery of agents is slower.
33
Maitra, Dr Jayabrata, Dr Saurav Sethia et Dr Priyanka Chilbule. « Reconstruction of Post-Burn Flexion Contractures of the Knee Joint with Perforator plus Fasciocutaneous Flaps ». SAS Journal of Surgery 7, no 12 (4 décembre 2021) : 760–67. http://dx.doi.org/10.36347/sasjs.2021.v07i12.004.
Résumé :
A post-burn flexion contracture of the knee joint is a disabling condition which interferes with an upright posture and a bipedal locomotion. Islanded perforator flaps have been used to resurface the tissue defect which is produced as a result of the contracture release. Despite their various advantages, they are limited by an increased tendency to undergo venous congestion. Perforator-plus flaps can be used to overcome this limitation, while retaining the merits of the islanded perforator flaps.Fifty four patients with post flame burn flexion contractures of the knee joints underwent surgical releases and coverages by various local fasciocutaneous perforator-plus flaps. The patients were followed up for 6 months and the various aspects of the functional and the aesthetic rehabilitations were assessed. All the local fasciocutaneous perforator-plus flaps resurfaced the tissue defect over popliteal fossa with good colour and texture match and maintenance of the contour. None of the flaps had any significant early or delayed complications which necessitated reoperations. All the patients were satisfied with the functional and aesthetic outcomes. Local fasciocutaneous perforator-plus flaps can be considered as one of the primary treatment modalities for the surgical release and reconstruction of post burn flexion contractures of the knee.
34
Morrison, Gregory M., D. Michael Revitt et J. Bryan Ellis. « The gully pot as a biochemical reactor ». Water Science and Technology 31, no 7 (1 avril 1995) : 229–36. http://dx.doi.org/10.2166/wst.1995.0239.
Résumé :
Roadside gully pots (catch basins) have been identified as potential sources that can make significant contributions to stormwater pollutant loadings. Between storm events the gully pot sediment and liquor undergo changes in composition as a result of biochemical reactions. Sediment maturation and acidic dissolution processes release pollutants from the contaminated chamber sediments and interstitial pore waters into the relatively clean gully pot liquor. Dissolved pollutant profiles for gully pot outflows therefore show substantial early contributions from gully pot liquor and interstitial waters reflecting microbial and geochemical degradation processes which act upon the trapped chamber sediments both during and between storm events. The majority of dissolved organic carbon is washed out in the gully pot outflow in the early low flow stages, suggesting that the main contributing source is the supernatant gully pot liquor. Small additional releases coincide with, and indicate additional releases of, soluble organics from the interstitial waters as the basal sediments are disturbed. Conductivity changes show that dissolved inorganics also exhibit efficient removal during the low flow stages of storms, with the absence of delayed peaks indicating a negligible contribution from the settled gully pot sediments. During storm events, low runoff rates produce marked decreases in pH levels from the initial gully pot liquor value of pH 6.0-7.1 to a value approaching typical rainfall levels (average rainfall pH = 4.1). This lowering of the pH indicates that the dissolved buffering agents initially present on the road surface and in the gully pot liquor have become depleted and exhaustion of dissolved Ca clearly illustrates this effect. Initial decreases in dissolved oxygen concentrations and redox potential are indicative of exposure of the reduced basal sediments as overlying supernatant liquor is washed out. A subsequent secondary decrease in redox potential, coinciding with increasing flows, is due to the additional release of reduced interstitial waters as the gully pot basal sediments are disturbed. Finally, dissolved oxygen levels return to normal as the oxygenated surface waters become predominant in the outflow waters.
35
Ezaki, Marybeth, Terri Beckwith et Scott N. Oishi. « Macrodactyly : decision-making and surgery timing ». Journal of Hand Surgery (European Volume) 44, no 1 (12 septembre 2018) : 32–42. http://dx.doi.org/10.1177/1753193418796441.
Résumé :
Macrodactyly is a rare condition in which fingers, hands or limb growth is unregulated, resulting in overgrowth of tissues in the affected extremities. It is critical to properly assess these extremities for signalling pathway, psychological impact and potential surgical intervention, to achieve the best possible outcome for each patient. Treatment approaches can vary, and patient and family expectations weigh heavily on care complexity. Common surgical procedures may include epiphysiodeses, osteotomies, debulking procedures, carpal tunnel releases, toe transfers and amputations. The selection and timing of these surgeries is a vital component of the approach, as delayed healing and excessive scarring may occur. The purpose of this review is to assist in the navigation of decision-making and surgical timing for patients presenting with overgrowth manifesting itself as macrodactyly.
36
Fletcher, TP, G. Shaw et MB Renfree. « Effects of bromocriptine at parturition in the tammar wallaby, Macropus eugenii ». Reproduction, Fertility and Development 2, no 1 (1990) : 79. http://dx.doi.org/10.1071/rd9900079.
Résumé :
Female tammar wallabies were treated with the dopamine agonist bromocriptine at the end of pregnancy to suppress the peripartum pulse of plasma prolactin. The animals were subsequently observed, and a series of blood samples taken to define the hormonal profiles before and immediately after parturition. Birth was observed in 4/5 control animals and occurred in 8/9 bromocriptine-treated animals. The peripartum peak in plasma PGFM concentrations was not affected by bromocriptine although the pulse of prolactin normally seen at parturition was completely abolished. The timing of luteolysis was apparently unaffected, as plasma progesterone concentrations fell similarly in both treated and control animals immediately after parturition. However, all of the neonates of the bromocriptine-treated animals died within 24 h, possibly because of a failure to establish lactation. Subsequent onset of post-partum oestrus was delayed or absent both in control and in bromocriptine-treated animals, suggesting that the frequent blood sampling and disturbances in the peripartum period interfered with these endocrine processes. It is concluded that both prolactin and prostaglandin can induce luteolysis in the pregnant wallaby, but that the normal sequence of events results from a signal of fetal origin inducing a prostaglandin release from the uterus, which in turn releases a pulse of prolactin that induces a progesterone decline.
37
Lamb, A. B., S. M. Salom et L. T. Kok. « Factors influencing aestivation in Laricobius nigrinus (Coleoptera : Derodontidae), a predator of Adelges tsugae (Hemiptera : Adelgidae) ». Canadian Entomologist 139, no 4 (août 2007) : 576–86. http://dx.doi.org/10.4039/n06-110.
Résumé :
AbstractLaricobius nigrinus Fender is being reared for release as a biological control agent for hemlock woolly adelgid (HWA), Adelges tsugae Annand. HWA is an introduced insect lethal to hemlock trees (Tsuga canadensis (L.) Carr. and T. caroliniana Engelm.) in the eastern United States. In nature, the predator (Laricobius nigrinus) and its prey (HWA) undergo a dormant period in the summer (aestivation). In the laboratory, the aestivation of L. nigrinus has not been synchronized with that of HWA, resulting in significant predator mortality. Four factors (genetics, temperature, photoperiod, and moisture) were investigated for their effects on aestivation in L. nigrinus. Both the number of individuals and the time at which they emerged from aestivation were measured in response to these factors. Temperature was the most important cue for termination of aestivation, and photoperiod was a modifying factor. High temperature and long day length delayed emergence and high moisture levels resulted in greater emergence but did not affect emergence time. Genetics, as represented by broods, was not a major factor in aestivation termination. These results have led to improvement in rearing L. nigrinus, since emergence from aestivation can now be synchronized with the active period of HWA. Increased success in rearing has expedited field releases of L. nigrinus in the eastern United States.
38
Roffi, Alice, Giuseppe Filardo, Elisa Assirelli, Carola Cavallo, Annarita Cenacchi, Andrea Facchini, Brunella Grigolo et al. « Does Platelet-Rich Plasma Freeze-Thawing Influence Growth Factor Release and Their Effects on Chondrocytes and Synoviocytes ? » BioMed Research International 2014 (2014) : 1–10. http://dx.doi.org/10.1155/2014/692913.
Résumé :
PRP cryopreservation remains a controversial point. Our purpose was to investigate the effect of freezing/thawing on PRP molecule release, and its effects on the metabolism of chondrocytes and synoviocytes. PRP was prepared from 10 volunteers, and a half volume underwent one freezing/thawing cycle. IL-1β, HGF, PDGF AB/BB, TGF-β1, and VEGF were assayed 1 hour and 7 days after activation. Culture media of chondrocytes and synoviocytes were supplemented with fresh or frozen PRP, and, at 7 days, proliferation, gene expression, and secreted proteins levels were evaluated. Results showed that in the freeze-thawed PRP the immediate and delayed molecule releases were similar or slightly lower than those in fresh PRP. TGF-β1 and PDGF AB/BB concentrations were significantly reduced after freezing both at 1 hour and at 7 days, whereas HGF concentration was significantly lower in frozen PRP at 7 days. In fresh PRP IL-1βand HGF concentrations underwent a significant further increase after 7 days. Similar gene expression was found in chondrocytes cultured with both PRPs, whereas in synoviocytes HGF gene expression was higher in frozen PRP. PRP cryopreservation is a safe procedure, which sufficiently preserves PRP quality and its ability to induce proliferation and the production of ECM components in chondrocytes and synoviocytes.
39
Li, Pan, Wenjie Wei, Xing Cai, Christian Soeller, Mark B. Cannell et Arun V. Holden. « Computational modelling of the initiation and development of spontaneous intracellular Ca 2+ waves in ventricular myocytes ». Philosophical Transactions of the Royal Society A : Mathematical, Physical and Engineering Sciences 368, no 1925 (28 août 2010) : 3953–65. http://dx.doi.org/10.1098/rsta.2010.0146.
Résumé :
Intracellular Ca 2+ dynamics provides excitation–contraction coupling in cardiac myocytes. Under pathological conditions, spontaneous Ca 2+ release events can lead to intracellular Ca 2+ travelling waves, which can break, giving transitory or persistent intracellular re-entrant Ca 2+ scroll waves. Intracellular Ca 2+ waves can trigger cellular delayed after-depolarizations of membrane potential, which if they occur in a cluster of a few hundred neighbouring myocytes may lead to cardiac arrhythmia. Quantitative prediction of the initiation and propagation of intracellular Ca 2+ waves requires the dynamics of Ca 2+ -induced Ca 2+ release, and the intracellular spatial distribution of Ca 2+ release units (CRUs). The spatial distribution of ryanodine receptor clusters within a few sarcomeres was reconstructed directly from confocal imaging measurements. It was then embedded into a three-dimensional ventricular cell model, with a resting membrane potential and simple stochastic Ca 2+ -induced Ca 2+ release dynamics. Isotropic global Ca 2+ wave propagation can be produced within the anisotropic intracellular architecture, by isotropic local Ca 2+ diffusion, and the branching Z-disc structure providing inter Z-disc pathways for Ca 2+ propagation. The branching Z-disc provides a broader spatial distribution of ryanodine receptor clusters across Z-discs, which reduces the likelihood of wave initiation by spontaneous Ca 2+ releases. Intracellular Ca 2+ dynamics during catecholaminergic polymorphic ventricular tachycardia (CPVT) was simulated phenomenologically by increasing the Ca 2+ sensitivity factor of the CRU, which results in an increased rate of Ca 2+ release events. Flecainide has been shown to prevent arrhythmias in a murine model of CPVT and in patients. The modelled actions of flecainide on the time course of Ca 2+ release events prevented the initiation of Ca 2+ waves.
40
Mishra, Raghav. « Development and Optimization of Floating Microspheres in Amethopterin ». Bioscience Biotechnology Research Communications 14, no 4 (25 décembre 2021) : 1538–43. http://dx.doi.org/10.21786/bbrc/14.4.26.
Résumé :
Due to the complexity of gastric emptying, as well as its considerable variability, the in vivo efficacy of drug delivery devices cannot be predicted. When it pertains to drugs with an absorption window in the upper small intestine, a controlled drug delivery system with a longer residence period in the stomach may be of considerable practical significance. Recent developments have shown that floating microspheres are particularly well suited for mixing sustained and delayed releases to achieve a variety of release models with a minimal risk of dumping. The aim of present investigation is to develop and analyze the floating microspheres of amethopterin, which after oral administration could increase the gastric residence time and enhance the bioavailability of the drug by sustained release and minimize the dose dependent side effects as well as improves patient compliance. Floating microspheres of ethyl cellulose, Polyvinyl alcohol and polyvinyl pyrrolidone-K90 were formulated by emulsification solvent evaporation technique. The various parameters of prepared microspheres were studied for SEM, flow properties, buoyancy, yield, percent drug loading, in vitro dissolution studies, stability in different pH and FTIR studies. Microspheres prepared with different concentrations of polymers were spherical in shape with smooth surface. The size of microspheres was in range of 256.02 µm and 362.84 µm. Good drug entrapment and buoyancy were observed for formulation F2. The in vitro drug release after 6h was found to be in range from 58.15% to 96.28%. It was established that the newly created floating microspheres of Amethopterin provide an appropriate and practical solution for the sustained release of medication over a longer period of time, resulting in increased oral bioavailability, effectiveness, as well as better patient compliance.
41
Hagstrum, J. T. « Infrasound and the avian navigational map ». Journal of Experimental Biology 203, no 7 (1 avril 2000) : 1103–11. http://dx.doi.org/10.1242/jeb.203.7.1103.
Résumé :
Birds can navigate accurately over hundreds to thousands of kilometres, and this ability of homing pigeons is the basis for a worldwide sport. Compass senses orient avian flight, but how birds determine their location in order to select the correct homeward bearing (map sense) remains a mystery. Also mysterious are rare disruptions of pigeon races in which most birds are substantially delayed and large numbers are lost. Here, it is shown that in four recent pigeon races in Europe and the northeastern USA the birds encountered infrasonic (low-frequency acoustic) shock waves from the Concorde supersonic transport. An acoustic avian map is proposed that consists of infrasonic cues radiated from steep-sided topographic features; the source of these signals is microseisms continuously generated by interfering oceanic waves. Atmospheric processes affecting these infrasonic map cues can explain perplexing experimental results from pigeon releases.
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Lee, Ji Yun, Shabitha Arumugarajah, Dameng Lian, Natsumi Maehara, Aaron R. Haig, Rita S. Suri, Toru Miyazaki et Lakshman Gunaratnam. « Recombinant apoptosis inhibitor of macrophage protein reduces delayed graft function in a murine model of kidney transplantation ». PLOS ONE 16, no 4 (23 avril 2021) : e0249838. http://dx.doi.org/10.1371/journal.pone.0249838.
Résumé :
Reperfusion injury following cold and warm ischemia (IRI) is unavoidable during kidney transplantation and contributes to delayed graft function (DGF) and premature graft loss. Death of tubular epithelial cells (TECs) by necrosis during IRI releases pro-inflammatory mediators (e.g. HMGB1), propagating further inflammation (necroinflammation) and tissue damage. Kidney Injury Molecule-1 (KIM-1) is a phagocytic receptor upregulated on proximal TECs during acute kidney injury. We have previously shown that renal KIM-1 protects the graft against transplant associated IRI by enabling TECs to clear apoptotic and necrotic cells, and that recognition of necrotic cells by KIM-1 is augmented in the presence of the opsonin, apoptosis inhibitor of macrophages (AIM). Here, we tested whether recombinant AIM (rAIM) could be used to mitigate transplant associated IRI. We administered rAIM or vehicle control to nephrectomised B6 mice transplanted with a single B6 donor kidney. Compared to grafts in vehicle-treated recipients, grafts from rAIM-treated mice exhibited significantly less renal dysfunction, tubular cell death, tissue damage, tubular obstruction, as well as local and systemic inflammation. Both mouse and human rAIM enhanced the clearance of necrotic cells by murine and human TECs, respectively in vitro. These data support testing of rAIM as a potential therapeutic agent to reduce DGF following kidney transplantation.
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Nelson, Victoria L. Boughton, Ariel L. Negrón, Inefta Reid, Justin A. Thomas, Leon Yang, Richard Z. Lin et Maricedes Acosta-Martínez. « Loss of PI3K p110αin the Adipose Tissue Results in Infertility and Delayed Puberty Onset in Male Mice ». BioMed Research International 2017 (2017) : 1–13. http://dx.doi.org/10.1155/2017/3756089.
Résumé :
Deletion of PI3K catalytic subunit p110αin adipose tissue (aP2-Cre/p110αflx/flx,α−/− hereafter) results in increased adiposity, glucose intolerance, and liver steatosis. Because this endocrine organ releases hormones like leptin, which are important in reproductive physiology, we investigated the reproductive phenotype ofα−/− males. Compared to controls,α−/− males displayed delayed onset of puberty accompanied by a reduction in plasma LH levels and testicular weight. At postnatal day 30,α−/− mice exhibited normal body weight but elevated fasted plasma leptin levels. Testicular leptin gene expression was increased, whereas expression of the cholesterol transporter StAR and of P450 cholesterol side chain cleavage enzyme was decreased. Adultα−/− males were infertile and exhibited hyperandrogenemia with normal basal LH, FSH, and estradiol levels. However, neither sperm counts nor sperm motility was different between genotypes. The mRNA levels of leptin and of 17-beta-dehydrogenase 3, and enzyme important for testosterone production, were significantly higher in the testis of adultα−/− males. The mRNA levels of ERα, an important regulator of intratesticular steroidogenesis, were lower in the testis of adult and peripubertalα−/− males. We propose that chronic hyperleptinemia contributes to the negative impact that disrupting PI3K signaling in adipocytes has on puberty onset, steroidogenesis, and fertility in males.
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Darbellay, Basile, Serge Arnaudeau, Charles R. Bader, Stephane Konig et Laurent Bernheim. « STIM1L is a new actin-binding splice variant involved in fast repetitive Ca2+ release ». Journal of Cell Biology 194, no 2 (25 juillet 2011) : 335–46. http://dx.doi.org/10.1083/jcb.201012157.
Résumé :
Cytosolic Ca2+ signals encoded by repetitive Ca2+ releases rely on two processes to refill Ca2+ stores: Ca2+ reuptake from the cytosol and activation of a Ca2+ influx via store-operated Ca2+ entry (SOCE). However, SOCE activation is a slow process. It is delayed by >30 s after store depletion because stromal interaction molecule 1 (STIM1), the Ca2+ sensor of the intracellular stores, must form clusters and migrate to the membrane before being able to open Orai1, the plasma membrane Ca2+ channel. In this paper, we identify a new protein, STIM1L, that colocalizes with Orai1 Ca2+ channels and interacts with actin to form permanent clusters. This property allowed the immediate activation of SOCE, a characteristic required for generating repetitive Ca2+ signals with frequencies within seconds such as those frequently observed in excitable cells. STIM1L was expressed in several mammalian tissues, suggesting that many cell types rely on this Ca2+ sensor for their Ca2+ homeostasis and intracellular signaling.
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S, Subimol, et Amjadkhan A. Pathan. « Formulation And In Vitro, In Vivo Evaluation of Colon Targeted Drug Delivery System Of 5-Fluorouracil ». International Journal of Membrane Science and Technology 10, no 3 (21 août 2023) : 3753–67. http://dx.doi.org/10.15379/ijmst.v10i3.3636.
Résumé :
Colon-targeted drug delivery systems can provide therapeutic benefits including better patient compliance and lower costs. The present investigation is aimed to design a colon specific microbially triggered system using biodegradable co-polymer mixtures. The calibration curves of 5-FU were measured in distilled water, 0.1N HCl and phosphate buffer of pH 6.8 and 7.4 which showed good linearity. Compatibility study of pure drugs, excipients and their physical mixtures were evaluated and passed as per standards. Solubility determination was carried out in different solvents. Satisfactory results were found from evaluation of micromeritic parameters such as flow property, in-vitro dissolution study and kinetic study. The prime focus of the study was to design and evaluate a swelling dependent delayed release system for a colonic delivery of anticancer agent 5-Fluorouracil (5-FU) and further to determine the effects of carboxy polymer (Carbopol 71G-NF) on release behavior of 5-FU from a matrix tablet system containing different amounts of inulin (a biodegradable oligofructose) aiding in enzymatic degradation by colonic microflora. Mixed film coating with a blend of Ethyl cellulose: Eudragit®S-100 (2:1) at coat weight levels of 2%w/w, 4%w/w and 6.0%w/w was carried out respectively, which further retarded the drug release in the initial hours of the in-vitro dissolution profile. Swelling studies were also carried out on uncoated matrix tablet batches. The releases studies with or without rat cecal contents were performed on optimized batches and the samples were analyzed by a validated RP-HPLC method. In-vitro rat cecal study results revealed that complete drug release would occur from the tablets in the human colonic microenvironment. The study revealed an effective site-specific delivery of a hydrophilic chemotherapeutic agent, 5-FU to the colon for the treatment of various local as well as systemic pathologies.
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Lam, W. F., A. A. Masclee, E. S. Muller et C. B. Lamers. « Effect of hyperglycemia on gastric acid secretion during the gastric phase of digestion ». American Journal of Physiology-Gastrointestinal and Liver Physiology 272, no 5 (1 mai 1997) : G1116—G1121. http://dx.doi.org/10.1152/ajpgi.1997.272.5.g1116.
Résumé :
We have examined the effect of an acute stable hyperglycemia on gastric acid secretion during the gastric phase of digestion. Gastric acid output was measured with a recovery marker (phenol red) under basal conditions and after repeated intragastric instillation of a liquid meal in seven healthy subjects on two separate occasions: during normoglycemia (serum glucose, 15 mM). Premeal gastric acid output was significantly (P < 0.05) reduced during hyperglycemia compared with during normoglycemia (2.6 +/- 1.0 vs. 5.8 +/- 1.8 mmol/h). Intragastric meal-stimulated incremental acid output during hyperglycemia was significantly (P < 0.05) reduced compared with during normoglycemia (19 +/- 4 vs. 38 +/- 9 mmol/120 min). Meal-stimulated gastrin release during hyperglycemia was significantly (P < 0.05) reduced compared with that during normoglycemia (4.9 +/- 1.3 vs. 6.6 +/- 1.6 micrograms.1(-1).120 min-1). The intragastric meal induced significant (P < 0.05) increases in pancreatic polypeptide concentrations only during normoglycemia. During hyperglycemia, recovery rates of gastric contents were significantly (P < 0.05) increased compared with during normoglycemia, both before (81 +/- 4 vs. 71 +/- 6%) and after (72 +/- 4 vs. 57 +/- 4%) meal ingestion, pointing to delayed gastric emptying of liquids during hyperglycemia. In conclusion, 1) gastric acid secretion under unstimulated conditions and during the gastric phase of digestion is reduced during hyperglycemia; 2) meal-stimulated gastrin release is significantly reduced during hyperglycemia; 3) the reduction in meal-stimulated acid output is correlated with the reduction in gastrin releases; and 4) pancreatic polypeptide secretion is significantly reduced during hyperglycemia, pointing to impaired vagal cholinergic tone.
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Baxter, Richard, Robyn Merkel-Walsh, Barbara Stark Baxter, Ashley Lashley et Nicholas R. Rendell. « Functional Improvements of Speech, Feeding, and Sleep After Lingual Frenectomy Tongue-Tie Release : A Prospective Cohort Study ». Clinical Pediatrics 59, no 9-10 (28 mai 2020) : 885–92. http://dx.doi.org/10.1177/0009922820928055.
Résumé :
Recent studies suggest that speech, solid feeding, and sleep difficulties may be linked to restricted tongue function. Children with tongue restrictions and speech, feeding, and sleep issues underwent lingual frenectomies with a CO2 laser, paired with myofunctional exercises. Questionnaires were completed before, 1 week after, and 1 month following treatment. Thirty-seven patients participated in the study (mean age 4.2 years [range 13 months to 12 years]). Overall, speech improved in 89%, solid feeding improved in 83%, and sleep improved in 83% of patients as reported by parents. Fifty percent (8/16) of speech-delayed children said new words after the procedure ( P = .008), 76% (16/21) of slow eaters ate more rapidly ( P < .001), and 72% (23/32) of restless sleepers slept less restlessly ( P < .001). After tongue-tie releases paired with exercises, most children experience functional improvements in speech, feeding, and sleep. Providers should screen for oral restrictions in children and refer for treatment when functions are impaired.
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Tvedskov, JF, P. Tfelt-Hansen, KA Petersen, LT Jensen et J. Olesen. « CGRP receptor antagonist olcegepant (BIBN4096BS) does not prevent glyceryl trinitrate-induced migraine ». Cephalalgia 30, no 11 (7 avril 2010) : 1346–53. http://dx.doi.org/10.1177/0333102410363491.
Résumé :
There is a striking similarity between the migraine-provoking effect of the nitric oxide (NO) donor glyceryl trinitrate (GTN) and that of calcitonin gene-related peptide (CGRP). We tested the hypothesis that NO releases CGRP to cause the delayed migraine attack after GTN. Methods: In a double-blind-cross-over study, 13 migraine without aura (MO) patients were administered GTN 0.5 µg/kg/minute for 20 minutes and subsequently BIBN4096BS (olcegepant) 10 mg or placebo. Headache scores and development of MO were followed for 24 hours. Results: MO developed in seven of 13 with olcegepant and in nine of 13 with placebo ( p = 0.68). The headache scores were similar after the two treatments ( p = 0.58). Thus CGRP receptor blockade did not prevent GTN-induced migraine. Conclusions: The present study indicates that NO does not induce migraine by liberating CGRP. The most likely explanation for our findings is that CGRP has its effect higher than NO in the cascade of events leading to MO attacks.
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Bubulya, Paula A., Kannanganattu V. Prasanth, Thomas J. Deerinck, Daniel Gerlich, Joel Beaudouin, Mark H. Ellisman, Jan Ellenberg et David L. Spector. « Hypophosphorylated SR splicing factors transiently localize around active nucleolar organizing regions in telophase daughter nuclei ». Journal of Cell Biology 167, no 1 (11 octobre 2004) : 51–63. http://dx.doi.org/10.1083/jcb.200404120.
Résumé :
Upon completion of mitosis, daughter nuclei assemble all of the organelles necessary for the implementation of nuclear functions. We found that upon entry into daughter nuclei, snRNPs and SR proteins do not immediately colocalize in nuclear speckles. SR proteins accumulated in patches around active nucleolar organizing regions (NORs) that we refer to as NOR-associated patches (NAPs), whereas snRNPs were enriched at other nuclear regions. NAPs formed transiently, persisting for 15–20 min before dissipating as nuclear speckles began to form in G1. In the absence of RNA polymerase II transcription, NAPs increased in size and persisted for at least 2 h, with delayed localization of SR proteins to nuclear speckles. In addition, SR proteins in NAPs are hypophosphorylated, and the SR protein kinase Clk/STY colocalizes with SR proteins in NAPs, suggesting that phosphorylation releases SR proteins from NAPs and their initial target is transcription sites. This work demonstrates a previously unrecognized role of NAPs in splicing factor trafficking and nuclear speckle biogenesis.
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Huang, Xuan, Siew Hong Teoh et Yinglei Zhang. « Tone Management ». Accounting Review 89, no 3 (1 décembre 2013) : 1083–113. http://dx.doi.org/10.2308/accr-50684.
Résumé :
ABSTRACT We investigate whether and when firms manage the tone of words in earnings press releases, and how investors react to tone management. We estimate abnormal positive tone, ABTONE, as a measure of tone management from residuals of a tone model that controls for firm quantitative fundamentals such as performance, risk, and complexity. We find that ABTONE predicts negative future earnings and cash flows, is positively associated with upward perception management events, such as, just meeting/beating thresholds, future earnings restatements, SEO, and M&A, and is negatively associated with a downward perception management event, stock option grants. ABTONE has a positive stock return effect at the earnings announcement and a delayed negative reaction in the one and two quarters afterward. Balance sheet constrained firms and older firms are more likely to employ tone management over accruals management. Overall, the evidence is consistent with managers using strategic tone management to mislead investors about firm fundamentals.