We investigate the viscosity dependence on concentration and molecular weight of semiflexible polyelectrolyte sodium carboxymethylcellulose (NaCMC) in aqueous salt-free and NaCl solutions. Combining ...new measurements and extensive literature data, we establish relevant power laws and crossovers over a wide range of degree of polymerization (N) as well as polymer (c) and salt (c s) concentrations. In salt-free solution, the overlap concentration shows the expected c* ∝ N –2 dependence, and the entanglement crossover scales as c e ∝ N –0.6±0.3, in strong disagreement with scaling theory for which c e ∝ c* is expected, but matching the behavior found for flexible polyelectrolytes. A second crossover, to a steep concentration dependence for specific viscosity (ηsp ∝ c 3.5±0.2), commonly assigned to the concentrated regime, is shown to follow c** ∝ N –0.6±0.2 (with c**/c e ≃ 6) which thus suggests instead a dynamic crossover, possibly related to entanglement. The scaling of c* and c e in 0.01 and 0.1 M NaCl shows neutral polymer in good solvent behavior, characteristic of highly screened polyelectrolyte solutions. This unified scaling picture enables the estimation of viscosity of ubiquitous NaCMC solutions as a function of N, c, and c s and establishes the behavior expected for a range of semiflexible polyelectrolyte solutions.
We use the Liénard–Wiechert potential to show that very violent fluctuations are experienced by an electromagnetic charged extended particle when it is perturbed from its rest state. The feedback ...interaction of Coulombian and radiative fields among different charged parts of the particle makes uniform motion unstable. Then, we show that radiative fields and radiation reaction produce dissipative and antidamping effects, triggering a self-oscillation. Finally, we compute the self-potential, which in addition to rest and kinetic energy, gives rise to a new contribution that shares features with the quantum potential. We suggest that this contribution to self-energy produces a symmetry breaking of the Lorentz group, bridging classical electromagnetism and quantum mechanics.
Despite clear evidence of a neuroprotective physiological role of amyloid precursor protein (APP) and its non‐amyloidogenic processing products, APP has been investigated mainly in animal and ...cellular models of amyloid pathology in the context of Alzheimer's disease. The rare familial mutations in APP and presenilin‐1/2, which sometimes drive increased amyloid β (Aβ) production, may have unduly influenced Alzheimer's disease research. APP and its cleavage products play important roles in cellular and mitochondrial metabolism, but many studies focus solely on Aβ. Mitochondrial bioenergetic metabolism is essential for neuronal function, maintenance and survival, and multiple reports indicate mitochondrial abnormalities in patients with Alzheimer's disease. In this review, we focus on mitochondrial abnormalities reported in sporadic Alzheimer's disease patients and the role of full‐length APP and its non‐amyloidogenic fragments, particularly soluble APPα, on mitochondrial bioenergetic metabolism. We do not review the plethora of animal and in vitro studies using mutant APP/presenilin constructs or experiments using exogenous Aβ. In doing so, we aim to invigorate research and discussion around non‐amyloidogenic APP processing products and the mechanisms linking mitochondria and complex neurodegenerative disorders such as sporadic Alzheimer's disease.
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This article is part of a themed section on Therapeutics for Dementia and Alzheimer's Disease: New Directions for Precision Medicine. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.18/issuetoc
The continuous catalytic pyrolysis of high density polyethylene (HDPE) has been carried out in a two-step reaction system involving a pyrolysis conical spouted bed reactor followed by a catalytic ...fixed bed reactor. The good performance of the conical spouted bed reactor has allowed using a low temperature in thermal cracking (500°C) without defluidization problems, obtaining a volatile stream with a 90wt.% overall yield of C₁₂–C₂₀ and waxes in the first step. The effect of the second-step operating conditions on product yields and composition has been studied using a catalyst based on a HZSM-5 (SiO₂/Al₂O₃=30) zeolite. The influence of temperature in the 350–550°C range and space–time in the 0–8gcₐₜ min gHDPE ⁻¹ range has been studied. An increase in temperature or space–time gives way to an increase in the yield of light olefins, reaching a value of 62.9wt.% at 550°C and 8 gcₐₜ min gHDPE ⁻¹, with the individual yields of ethylene, propylene and butenes being 10.6, 35.6 and 16.7wt.%, respectively. Although the yield of single-ring aromatics increases when both variables studied are increased, the maximum yield obtained was lower than 13wt.%. The yield of waxes (the main product in the first step) is negligible even at low temperatures or spaces-times, which evidences the efficiency of the catalytic step.
Macrophages play an essential role in the resolution of tissue damage through removal of necrotic cells, thus paving the way for tissue regeneration. Macrophages also directly support the formation ...of new tissue to replace the injury, through their acquisition of an anti-inflammatory, or M2, phenotype, characterized by a gene expression program that includes IL-10, the IL-13 receptor, and arginase 1. We report that deletion of two CREB-binding sites from the Cebpb promoter abrogates Cebpb induction upon macrophage activation. This blocks the downstream induction of M2-specific Msr1, Il10, II13ra, and Arg-1 genes, whereas the inflammatory (M1) genes Il1, Il6, Tnfa, and Il12 are not affected. Mice carrying the mutated Cebpb promoter (βΔCre) remove necrotic tissue from injured muscle, but exhibit severe defects in muscle fiber regeneration. Conditional deletion of the Cebpb gene in muscle cells does not affect regeneration, showing that the C/EBPβ cascade leading to muscle repair is muscle-extrinsic. While βΔCre macrophages efficiently infiltrate injured muscle they fail to upregulate Cebpb, leading to decreased Arg-1 expression. CREB-mediated induction of Cebpb expression is therefore required in infiltrating macrophages for upregulation of M2-specific genes and muscle regeneration, providing a direct genetic link between these two processes.
We tested the fit of the social cognitive choice model Lent, R.W., Brown, S.D., & Hackett, G. (1994). Toward a unifying social cognitive theory of career and academic interest, choice, and ...performance Monograph.
Journal of Vocational Behavior, 45, 79–122 to the data across gender, educational level, and type of university among students in a variety of computing disciplines. Participants were 1208 students at 21 historically Black and 21 predominantly White universities. They completed measures of self-efficacy, outcome expectations, interests, goals, and social supports and barriers with respect to computing majors. The SCCT model yielded adequate fit to the data across each of the grouping variables. Implications for future research on SCCT’s choice hypotheses in the context of science and engineering-related fields are discussed.
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•The fountain confined conical spouted bed enhances the performance of primary catalysts.•Dolomite and γ-alumina improved syngas composition and reduced tar content.•Olivine and FCC ...catalysts reduced tar content, but hardly affect syngas composition.•The lowest tar content (5.0 g Nm−3) was obtained using dolomite as catalyst.•Light PAHs were the prevailing tar compounds on all the catalysts studied.
The performances of the primary catalysts olivine, dolomite, γ-alumina and FCC spent catalyst were evaluated in the continuous steam gasification of sawdust in a bench-scale plant equipped with a fountain confined conical spouted bed reactor. The experiments were carried out at 850 °C, and the efficiency of the gasification process was defined by gas yield, H2 production, tar concentration and composition, and carbon conversion efficiency. The benefits of the fountain confiner not only helped to improve the gas-solid contact, and therefore favoured the primary catalysts’ reforming and cracking activity, but also enhanced H2 production and reduce tar formation. Thus, dolomite and γ-alumina recorded the lowest values of tar, 5.0 and 6.7 g Nm−3, respectively, which corresponded to 79% and 72% tar reduction compared to the inert sand, whereas olivine and the FCC spent catalyst recorded higher tar contents, 20.6 and 16.2 g Nm−3, respectively. It is noteworthy that light PAHs were the most abundant species in the tar (60 wt% of the whole tar content).
Radiation intensity and carbon dioxide (CO.sub.2) concentration can be precisely controlled to manipulate plant yield and quality. Due to increased plant densities during seedling production, fewer ...inputs per plant are required, creating the potential to increase production efficiency. Therefore, the objectives of this research were to: 1) quantify the extent radiation intensity and CO.sub.2 concentration under sole-source lighting influence morphology and yield of sweet basil (Ocimum basilicum) seedlings, and 2) determine if differences in morphology, yield, and volatile organic compound (VOC) concentration persist after transplant in a common environment. Sweet basil 'Nufar' seedlings were grown in growth chambers with target CO.sub.2 concentrations of 500 or 1,000 mumol·mol.sup.-1 under light-emitting diodes (LEDs) providing target photosynthetic photon flux densities (PPFD) of 100, 200, 400, or 600 mumol·m.sup.-2 ·s.sup.-1 for 16 h per day. After two weeks, seedlings were transplanted into a common greenhouse environment and grown until harvest. At transplant and three weeks after transplant (harvest), growth and developmental differences were quantified along with key terpenoid and phenylpropanoid concentrations at harvest. Radiation intensity and CO.sub.2 interacted influencing many aspects of plant morphology, though CO.sub.2 concentration effects were less pronounced than those of radiation intensity. As radiation intensity during seedling production increased from 100 to 600 mumol·m.sup.-2 ·s.sup.-1, basil seedlings were 38% taller, had a 713% larger leaf area, and had 65% thicker stems; at harvest, plants were 24% taller, had 56% more branches, 28% more nodes, 22% thicker stems, and weighed 80% more when fresh and dry. Additionally, after growing in a common environment for three weeks, eugenol concentration was greater in plants grown under a PPFD of 600 mumol·m.sup.-2 ·s.sup.-1 as seedlings compared to lower intensities. Therefore, increasing radiation intensity during seedling production under sole-source lighting can carry over to increase subsequent yield and eugenol concentration during finished production.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
With the energetic particle telescope (EPT) performing with direct electron and proton discrimination on board the ESA satellite PROBA-V, we analyze the high-resolution measurements of the charged ...particle radiation environment at an altitude of 820 km for the year 2015. On 17 March 2015, a big geomagnetic storm event injected unusual fluxes up to low radial distances in the radiation belts. EPT electron measurements show a deep dropout at L > 4 starting during the main phase of the storm, associated to the penetration of high energy fluxes at L < 2 completely filling the slot region. After 10 days, the formation of a new slot around L = 2.8 for electrons of 500–600 keV separates the outer belt from the belt extending at other longitudes than the South Atlantic Anomaly. Two other major events appeared in January and June 2015, again with injections of electrons in the inner belt, contrary to what was observed in 2013 and 2014. These observations open many perspectives to better understand the source and loss mechanisms, and particularly concerning the formation of three belts.
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