292 research outputs found
Auditory masking - A study of its physiological mechanism and of correlations between physiological and psychological observations First quarterly progress report, period ending 30 Jun. 1965
Psychological and physiological study of auditory maskin
Periodicity of high-order functions in the CNS Final progress report, year ending 30 Jun. 1971
Analysis of cerebral slow potentials underlying human attentive processes in central nervous syste
Coarsening of Two Dimensional Foam on a Dome
In this paper we report on bubble growth rates and on the statistics of
bubble topology for the coarsening of a dry foam contained in the narrow gap
between two hemispheres. By contrast with coarsening in flat space, where
six-sided bubbles neither grow nor shrink, we observe that six sided bubbles
grow with time at a rate that depends on their size. This result agrees with
the modification to von Neumann's law predicted by J.E. Avron and D. Levine.
For bubbles with a different number of sides, except possibly seven, there is
too much noise in the growth rate data to demonstrate a difference with
coarsening in flat space. In terms of the statistics of bubble topology, we
find fewer 3, 4, and 5 sided bubbles, and more 6 and greater sided bubbles, in
comparison with the stationary distribution for coarsening in flat space. We
also find good general agreement with the Aboav-Weaire law for the average
number of sides of the neighbors of an n-sided bubble
Tratamento da palha de trigo com NaOH, no ganho de peso de bovinos suplementados com blocos de melaço-uréia
A uniform area of wheat stubble was divided into three paddocks, 1.2 ha each: A - standing stubble; B - baled stubble: and C - sodium hydroxide sprayed and baled stubble. Sodium hydroxide solution (40 g of NaOH per kg of straw) was sprayed into the chute of a forage harvester during the harvesting operation at the rate of 400 kg of solution per t of'straw. Each paddock was stocked with eight Friesian heifers and grazing was restricted to a 1/6 portion for the first week and extended to sucessive 1/6 portions weekly over a 42-day period. Urea, molasses and minerals supplement blocks were available ad lib in the three paddocks. Animals were weighed weekly and liveweight changes calculated as the coefficients of liveweight regressed against time. Liveweight changes were -352, -312, and +23 g/head/day on treatments A, B and C, respectively (C >A and B; P A e B; P<0,01). A digestibilidade da matéria orgânica expressa na matéria seca (DMOS) in vitro foi 38 e 53% para palhas não tratadas ou tratadas com soda cáustica, respectivamente
Periodicity of high-order neural functions
The results of recent studies on higher order, integrative processes in the central nervous system are reported. Attempts were made to determine whether these processes exhibit any ongoing rhythmicity which might manifest itself in alterations of attention and alertness. Experiments were also designed to determine if a periodicity approximating that of the REM could be detected in various parameters of brain electrical activity
Exploring the Nerve Regenerative Capacity of Compounds with Differing Affinity for PPARγ In Vitro and In Vivo
Damage to peripheral nerves can cause debilitating consequences for patients such as lifelong pain and disability. At present, no drug treatments are routinely given in the clinic following a peripheral nerve injury (PNI) to improve regeneration and remyelination of damaged nerves. Appropriately targeted therapeutic agents have the potential to be used at different stages following nerve damage, e.g., to maintain Schwann cell viability, induce and sustain a repair phenotype to support axonal growth, or promote remyelination. The development of therapies to promote nerve regeneration is currently of high interest to researchers, however, translation to the clinic of drug therapies for PNI is still lacking. Studying the effect of PPARγ agonists for treatment of peripheral nerve injures has demonstrated significant benefits. Ibuprofen, a non-steroidal anti-inflammatory drug (NSAID), has reproducibly demonstrated benefits in vitro and in vivo, suggested to be due to its agonist action on PPARγ. Other NSAIDs have demonstrated differing levels of PPARγ activation based upon their affinity. Therefore, it was of interest to determine whether affinity for PPARγ of selected drugs corresponded to an increase in regeneration. A 3D co-culture in vitro model identified some correlation between these two properties. However, when the drug treatments were screened in vivo, in a crush injury model in a rat sciatic nerve, the same correlation was not apparent. Further differences were observed between capacity to increase axon number and improvement in functional recovery. Despite there not being a clear correlation between affinity and size of effect on regeneration, all selected PPARγ agonists improved regeneration, providing a panel of compounds that could be explored for use in the treatment of PNI
Efeito do tratamento com soda cáustica e suplementação protéica de feno de Paspalum dilatatum no consumo e ganho de peso de bovinos
Mature Paspalum dilatatum hay was baled untreated, or sprayed with a solution supplying 12 g N and 1,2 g S/kg forage, as urea and NaHSO4, respectively, with and without the addition of caustic soda (40 g NaOH/kg forage). Sprayed forage was left in a moist condition in windrows for 24 hours before tedding and baling. Forages were chopped into 5-10 cm length and offered ad lib. to 40 Hereford streers and heifers housed in individual stalls and allocated to five treatments as follows: A) untreated hay; B) N + S; C) N + S + 300 g meat meal/head/day; D) N + S plus sodium hydroxide; E) N + S plus sodium hydroxide plus 300 g meat meal/head/day. Animals on treatment A suffered muscular trembling and ataxia and were removed from the trial. Liveweights were recorded twice weekly over 44 days and liveweight changes calculated as the coefficients of liveweight regressed against time. Liveweight gains did not differ significantly, being 471, 474, 547 and 525 g/head/day on treatments B, C, D and E, respectively. Voluntary dry matter intakes were higher on treatments D and E than on treatments B and C (D, E > B, C; P B, C; P < 0,05), sendo 4,18; 3,93; 3,62 e 3,73 kg/cab/dia, respectivamente. A digestibilidade da matéria seca (DMS) in vivo foi semelhante em todos os tratamentos (52%)
Development of ibuprofen-loaded electrospun materials suitable for surgical implantation in peripheral nerve injury
The development of nerve wraps for use in the repair of peripheral nerves has shown promise over recent years. A pharmacological effect to improve regeneration may be achieved by loading such materials with therapeutic agents, for example ibuprofen, a non-steroidal anti-inflammatory drug with neuroregenerative properties. In this study, four commercially available polymers (polylactic acid (PLA), polycaprolactone (PCL) and two co-polymers containing different ratios of PLA to PCL) were used to fabricate ibuprofen-loaded nerve wraps using blend electrospinning. In vitro surgical handling experiments identified a formulation containing a PLA/PCL 70/30 molar ratio co-polymer as the most suitable for in vivo implantation. In a rat model, ibuprofen released from electrospun materials significantly improved the rate of axonal growth and sensory recovery over a 21-day recovery period following a sciatic nerve crush. Furthermore, RT-qPCR analysis of nerve segments revealed that the anti-inflammatory and neurotrophic effects of ibuprofen may still be observed 21 days after implantation. This suggests that the formulation developed in this work could have potential to improve nerve regeneration in vivo
Engineered neural tissue made using hydrogels derived from decellularised tissues for the regeneration of peripheral nerves
Engineered neural tissue (EngNT) promotes in vivo axonal regeneration. Decellularised materials (dECM) are complex biologic scaffolds that can improve the cellular environment and also encourage positive tissue remodelling in vivo. We hypothesised that we could incorporate a hydrogel derived from a decellularised tissue (dECMh) into EngNT, thereby providing an alternative to the currently used purified collagen I hydrogel for the first time. Decellularisation was carried out on bone (B-ECM), liver (LIV-ECM), and small intestinal (SIS-ECM) tissues and the resultant dECM was biochemically and mechanically characterised. dECMh differed in mechanical and biochemical properties that likely had an effect on Schwann cell behaviour observed in metabolic activity and contraction profiles. Cellular alignment was observed in tethered moulds within the B-ECM and SIS-ECM derived hydrogels only. No difference was observed in dorsal root ganglia (DRG) neurite extension between the dECMh groups and collagen I groups when applied as a coverslip coating, however, when DRG were seeded atop EngNT constructs, only the B-ECM derived EngNT performed similarly to collagen I derived EngNT. B-ECM EngNT further exhibited similar axonal regeneration to collagen I EngNT in a 10 mm gap rat sciatic nerve injury model after 4 weeks. Our results have shown that various dECMh can be utilised to produce EngNT that can promote neurite extension in vitro and axonal regeneration in vivo
Pharmacological inhibition of RAS overcomes FLT3 inhibitor resistance in FLT3-ITD+ AML through AP-1 and RUNX1
\ua9 2024 The Author(s). AML is characterized by mutations in genes associated with growth regulation such as internal tandem duplications (ITD) in the receptor kinase FLT3. Inhibitors targeting FLT3 (FLT3i) are being used to treat patients with FLT3-ITD+ but most relapse and become resistant. To elucidate the resistance mechanism, we compared the gene regulatory networks (GRNs) of leukemic cells from patients before and after relapse, which revealed that the GRNs of drug-responsive patients were altered by rewiring their AP-1-RUNX1 axis. Moreover, FLT3i induces the upregulation of signaling genes, and we show that multiple cytokines, including interleukin-3 (IL-3), can overcome FLT3 inhibition and send cells back into cycle. FLT3i leads to loss of AP-1 and RUNX1 chromatin binding, which is counteracted by IL-3. However, cytokine-mediated drug resistance can be overcome by a pan-RAS inhibitor. We show that cytokines instruct AML growth via the transcriptional regulators AP-1 and RUNX1 and that pan-RAS drugs bypass this barrier
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