44 research outputs found
Phenomenology and physical origin of shear-localization and shear-banding in complex fluids
We review and compare the phenomenological aspects and physical origin of
shear-localization and shear-banding in various material types, namely
emulsions, suspensions, colloids, granular materials and micellar systems. It
appears that shear-banding, which must be distinguished from the simple effect
of coexisting static-flowing regions in yield stress fluids, occurs in the form
of a progressive evolution of the local viscosity towards two significantly
different values in two adjoining regions of the fluids in which the stress
takes slightly different values. This suggests that from a global point of view
shear-banding in these systems has a common physical origin: two physical
phenomena (for example, in colloids, destructuration due to flow and
restructuration due to aging) are in competition and, depending on the flow
conditions, one of them becomes dominant and makes the system evolve in a
specific direction.Comment: The original publication is available at http://www.springerlink.co
The disruption of proteostasis in neurodegenerative diseases
Cells count on surveillance systems to monitor and protect the cellular proteome which, besides being highly heterogeneous, is constantly being challenged by intrinsic and environmental factors. In this context, the proteostasis network (PN) is essential to achieve a stable and functional proteome. Disruption of the PN is associated with aging and can lead to and/or potentiate the occurrence of many neurodegenerative diseases (ND). This not only emphasizes the importance of the PN in health span and aging but also how its modulation can be a potential target for intervention and treatment of human diseases.info:eu-repo/semantics/publishedVersio
Wear and corrosion interactions on titanium in oral environment : literature review
The oral cavity is a complex environment where corrosive substances from dietary, human saliva, and oral biofilms may accumulate in retentive areas of dental implant systems and prostheses promoting corrosion at their surfaces. Additionally, during mastication, micromovements may occur between prosthetic joints causing a relative motion between contacting surfaces, leading to wear. Both processes (wear and corrosion) result in a bio-tribocorrosion system once that occurs in contact with biological tissues and fluids. This review paper is focused on the aspects related to the corrosion and wear behavior of titanium-based structures in the oral environment. Furthermore, the clinical relevance of the oral environment is focused on the harmful effect that acidic substances and biofilms, formed in human saliva, may have on titanium surfaces. In fact, a progressive degradation of titanium by wear and corrosion (tribocorrosion) mechanisms can take place affecting the performance of titanium-based implant and prostheses. Also, the formation of wear debris and metallic ions due to the tribocorrosion phenomena can become toxic for human tissues. This review gathers knowledge from areas like materials sciences, microbiology, and dentistry contributing to a better understanding of bio-tribocorrosion processes in the oral environment.(undefined
Feasibility and psychometric properties of the German 12-item WHO Disability Assessment Schedule (WHODAS 2.0) in a population-based sample of patients with myocardial infarction from the MONICA/KORA myocardial infarction registry
Mechanical and Water Intake Properties of Banana-Carbon Hybrid Fiber Reinforced Polymer Composites
Stochastic dietary restriction using a Markov-chain feeding protocol elicits complex, life history response in medflies
Lifespan in individually housed medflies (virgins of both sexes) and daily reproduction for females were studied following one of 12 dietary restriction (DR) treatments in which the availability of high-quality food (yeast–sugar mixture) for each fly was based on a Markov chain feeding scheme – a stochastic dietary regime which specifies that the future dietary state depends only on the present dietary state and not on the path by which the present state was achieved. The stochastic treatments consisted of a combination of one of four values of a ‘discovery’ parameter and one of three values of a ‘persistence’ parameter. The results supported the hypotheses that: (i) longevity is extended in most medfly cohorts subject to stochastic DR; and (ii) longevity is more affected by the patch discovery than the patch persistence parameter. One of the main conclusions of the study is that, in combination with the results of earlier dietary restriction studies on the medfly, the results reinforce the concept that the details of the dietary restriction protocols have a profound impact on the sign and magnitude of the longevity extension relative to ad libitum cohorts and that a deeper understanding of the effect of food restriction on longevity is not possible without an understanding of its effect on reproduction.
PubMed Central versio
Arterial Obstruction on Computed Tomographic or Magnetic Resonance Angiography and Response to Intravenous Thrombolytics in Ischemic Stroke
Thrombolysis Outcomes in Acute Ischemic Stroke by Fluid-Attenuated Inversion Recovery Hyperintense Arteries
Background and Purpose: To determine factors associated with fluid-attenuated inversion recovery (FLAIR) hyperintense arteries (FLAIR-HAs) on magnetic resonance imaging and their prognostic significance in thrombolysis-treated patients with acute ischemic stroke from the ENCHANTED (Enhanced Control of Hypertension and Thrombolysis Stroke Study) trial alteplase-dose arm. Methods: Patients with acute ischemic stroke (N=293) with brain magnetic resonance imaging (FLAIR and diffusion-weighted imaging sequences) scanned <4.5 hours of symptom onset were assessed for location and extent (score) of FLAIR-HAs, infarct volume, large vessel occlusion (LVO), and other ischemic signs. Logistic regression models were used to determine predictors of FLAIR-HAs and the association of FLAIR-HAs with 90-day outcomes: favorable functional outcome (primary; modified Rankin Scale scores, 0-1), other modified Rankin Scale scores, and intracerebral hemorrhage. Results: Prior atrial fibrillation, LVO, large infarct volume, and anterior circulation infarction were independently associated with FLAIR-HAs. The rate of modified Rankin Scale scores 0 to 1 was numerically lower in patients with FLAIR-HAs versus without (69/152 [45.4%] versus 75/131 [57.3%]), as was the subset of LVO (37/93 [39.8%] versus 9/16 [56.3%]), but not in those without LVO (25/36 [69.4%] versus 60/106 [56.6%]). After adjustment for covariables, FLAIR-HAs were independently associated with increased primary outcome (adjusted odds ratio [95% CI]: overall 4.14 [1.63-10.50]; with LVO 4.92 [0.87-27.86]; no LVO 6.16 [1.57-24.14]) despite an increased risk of hemorrhagic infarct (4.77 [1.12-20.26]). Conclusions: FLAIR-HAs are more frequent in acute ischemic stroke with cardioembolic features and indicate potential for a favorable prognosis in thrombolysis-treated patients possibly mediated by LVO. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01422616