1,302 research outputs found
Evaluation of the neuroprotective potential of Trans-cinnamaldehyde in female Wistar rat model of insulin resistance
Background: Chronic hyperglycemia in type 2 diabetes is associated with altered cognitive function. Trans-cinnamaldehyde (TCA) is one of the active components in cinnamon. It has been reported to have many pharmacological activities such as anti-bacterial and anti-inflammatory properties. Aim and Objectives: This present work evaluates the neuroprotective effects of TCA in the hippocampus of insulin-resistant rats. Material and Methods: Twenty female adult Wistar rats were fed with high fat diet for 8 weeks and then injected with a low dose of
streptozotocin (30 mg/kg body weight intraperitoneally). Sixty mg/kg of TCA was orally administered for 4 weeks once daily. Y-maze and Morris water maze tests were employed to test for learning and memory. Fasting blood glucose, serum insulin, hippocampal Tumor Necrosis Factor-α (TNF-α), Nuclear Factor ÎșB (NFâÎșB) were assayed. Results: The high fat diet/streptozotocin-induced insulin resistant-rats, characterized by hyperglycemia and hyperinsulinemia performed poorly in the Y-maze and Morris water maze (38.17 ± 1.3 s) when compared with the
controls (26.67 ± 1.4 s), suggesting the impairment of learning and memory with corresponding increase in NFâÎșB and TNF-α in the hippocampus. Conclusion: Treatment with TCA significantly reversed diabetesâinduced impairment of
learning and memory. TCA as a prospective novel therapy in insulin-resistant subjects with dementia could be further explored
Strong Zonation of Benthic Communities Across a Tidal Freshwater Height Gradient
Trade-offs associated with environmental gradients generate patterns of diversity and govern community organisation in a landscape. In freshwaters, benthic community structure is driven by trade-offs along generally orthogonal gradients of habitat permanence and predationâwhere ephemeral systems are physiologically harsh because of drying stress, but inhabitants are less likely to be under the intense predation pressure of more permanent waterbodies. However, in tidal freshwaters, these two stressors are compounding, and the trade-offs associated with them are decoupled. 2. We investigated benthic community structure in a tidal freshwater habitat. These communities experience a suite of conditions atypical for a freshwater habitat: twice-daily drying; and high predation pressure by mobile fishes. We compared benthic communities at three tidal heights (low, mid, high) and contrasted these with nearby non-tidal freshwaters that varied in their hydrology (permanent, temporary). 3. We found that communities were more strongly differentiated in tidal freshwater habitats than between permanent and temporary inland freshwaters, which was surprising given the high interconnectedness and condensed longitudinal scale of tidal habitats. The differentiation of communities in tidal habitats was probably driven by the combined gradients of desiccation risk at low tide and intense predation by fish at high tideâa combination of pressures that are novel for the evolutionary history of the regional freshwater invertebrate fauna. 4. Our study provides evidence that environmental gradients can produce stronger patterns of community zonation than would be predicted for habitats that are spatially contiguous and have little or no dispersal limitation. These results give insight into how communities might respond if drivers of community structure are altered or reorganised from their regional or evolutionary norms
History and philosophy of science in Biology teaching
Neste trabalho, buscamos evidenciar a concepção de HistĂłria da Biologia que Ă© veiculada nos livros didĂĄticos. Para tanto, analisamos trĂȘs coleçÔes de livros de Biologia destinados ao Ensino MĂ©dio, e alguns livros universitĂĄrios usados em cursos de formação de professores. Ao analisar este material curricular foi possĂvel observar que a histĂłria apresentada Ă© desvinculada do contexto cultural de cada perĂodo histĂłrico, o que pode levar o aluno a construir uma falsa representação da ciĂȘncia e do fazer cientĂfico.In this work, we search forto evidences the conception of the History of Biology being is propagated in textbooks. We analyze three Biology book collections designed estined forto middle schooledium education, and some university books used in teacher education courses. When analyzing this curricular material it was possible to observe that the history of biology presented is disengaged from entailedofthe cultural context of each historical period, and this what can lead the student to construct a false representation of science and of scientific meaning making
Effects of Acceptance and Commitment Therapy on Impulsive Decision Making
This study examined the transdiagnostic effect of acceptance and commitment therapy (ACT) on impulsive decision making in a community sample. Forty adults were randomized to eight individual sessions of ACT or an inactive control. Participants completed pre-, mid-, and post-assessments for psychological symptoms, overall behavior change, valued living, delay discounting, psychological flexibility, and distress tolerance. Data were analyzed with multilevel modeling of growth curves. Significant interaction effects of time and condition were observed for psychological flexibility, distress tolerance, psychological symptoms, and the obstruction subscale of valued living. No significant interaction effect was found for two delay discounting tasks nor the progress subscale of valued living. The ACT condition had a significantly larger reduction of problem behavior at post-assessment. The results support use of ACT as a transdiagnostic treatment for impulsive behaviors. The lack of change in delay discounting contrasts previous research
Ecosystem biogeochemistry considered as a distributed metabolic network ordered by maximum entropy production
Author Posting. © The Author(s), 2009. This is the author's version of the work. It is posted here by permission of The Royal Society for personal use, not for redistribution. The definitive version was published in Philosophical Transactions of the Royal Society B 365 (2010): 1417-1427, doi:10.1098/rstb.2009.0272.We examine the application of the maximum entropy production principle for describing ecosystem biogeochemistry. Since ecosystems can be functionally stable despite changes in species composition, we utilize a distributed metabolic network for describing biogeochemistry, which synthesizes generic biological structures that catalyze reaction pathways, but is otherwise organism independent. Allocation of biological structure and regulation of biogeochemical reactions is determined via solution of an optimal control problem in which entropy production is maximized. However, because synthesis of biological structures cannot occur if entropy production is maximized instantaneously, we propose that information stored within the metagenome allows biological systems to maximize entropy production when averaged over time. This differs from abiotic systems that maximize entropy production at a point in space-time, which we refer to as the steepest descent pathway. It is the spatiotemporal averaging that allows biological systems to outperform abiotic processes in entropy production, at least in many situations. A simulation of a methanotrophic system is used to demonstrate the approach. We conclude with a brief discussion on the implications of viewing ecosystems as self organizing molecular machines that function to maximize entropy production at the ecosystem level of organization.The work presented here was funded by the PIE-LTER program (NSF OCE-0423565), as well as from NSF CBET-0756562, NSF EF-0928742 and NASA Exobiology and Evolutionary Biology (NNG05GN61G)
Tropical Herbivorous Phasmids, but Not Litter Snails, Alter Decomposition Rates By Modifying Litter Bacteria
Consumers can alter decomposition rates through both feces and selective feeding in many ecosystems, but these combined effects have seldom been examined in tropical ecosystems. Members of the detrital food web (litter-feeders or microbivores) should presumably have greater effects on decomposition than herbivores, members of the green food web. Using litterbag experiments within a field enclosure experiment, we determined the relative effects of common litter snails (Megalomastoma croceum) and herbivorous walking sticks (Lamponius portoricensis) on litter composition, decomposition rates, and microbes in a Puerto Rican rainforest, and whether consumer effects were altered by canopy cover presence. Although canopy presence did not alter consumersâ effects, focal organisms had unexpected influences on decomposition. Decomposition was not altered by litter snails, but herbivorous walking sticks reduced leaf decomposition by about 50% through reductions in high quality litter abundance and, consequently, lower bacterial richness and abundance. This relatively unexplored but potentially important link between tropical herbivores, detritus, and litter microbes in this forest demonstrates the need to consider autotrophic influences when examining rainforest ecosystem processes
Evaluating the Sustainability of a Small-Scale Low-Input Organic Vegetable Supply System in the United Kingdom
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