Ultralong and Mesoporous ZnO and γ-Al_2O_3 Oriented Nanowires Obtained by Template-assisted Hydrothermal Approach

Highly mesoporous Zn O and g-Al2O3nanowires（NWs） are both synthesized by a hydrothermal method using commercially available porous anodic aluminium oxide（AAO） as template. AAO membrane acts as template for Zn O NWs and both as template and precursor for g-Al2O3 NWs. The formation of intermediate phases of porous Zn6Al2（OH）16CO3and boehmite（g-Al OOH） were observed, both occurring during the hydrothermal synthesis of porous Zn O and g-Al2O3 NWs, respectively, and disappearing after annealing at 600 C. This novel template-assisted hydrothermal process leads to the formation of porous Zn O and g-Al2O3NWs（specific surface area of 192 m2 g 1and 263 m2 g 1, respectively）, showing pore sizes around 4 nm in diameter. The influence of the reaction parameters on the nanostructure morphology was also investigated. A Zn O seed layer, deposited on the AAO channels prior to the hydrothermal synthesis, leads to more compact Zn O nanowires（99 m2 g-1） protecting the AAO host from the chemical attack of the precursor solution.     

Optimization of fully aligned bioactive electrospun fibers for “in vitro” nerve guidance

Complex architecture of natural tissues such as nerves requires the use of multifunctional scaffolds with peculiar topological and biochemical signals able to address cell behavior towards specific events at the cellular (microscale) and macromolecular (nanoscale) level. In this context, the electrospinning technique is useful to generate fiber assemblies having peculiar fiber diameters at the nanoscale and patterned by unidirectional ways, to facilitate neurite extension via contact guidance. Following a bio-mimetic approach, fully aligned polycaprolactone fibers blended with gelatin macromolecules have been fabricated as potential bioactive substrate for nerve regeneration. Morphological and topographic aspects of electrospun fibers assessed by SEM/AFM microscopy supported by image analyses elaboration allow estimating an increase of fully aligned fibers from 5 to 39 % as collector rotating rate increases from 1,000 to 3,000 rpm. We verify that fully alignment of fibers positively influences in vitro response of hMSC and PC-12 cells in neurogenic way. Immunostaining images show that the presence of topological defects, i.e., kinks—due to more frequent fiber crossing—in the case of randomly organized fiber assembly concurs to interfere with proper neurite outgrowth. On the contrary, fully aligned fibers without kinks offer a more efficient contact guidance to direct the orientation of nerve cells along the fibers respect to randomly organized ones, promoting a high elongation of neurites at 7 days and the formation of bipolar extensions. So, this confirms that the topological cue of fully alignment of fibers elicits a favorable environment for nerve regeneration.     

Tailoring dialysis and resuming low‐protein diets may favor chronic dialysis discontinuation: Report on three cases

Renal function recovery (RFR), defined as the discontinuation of dialysis after 3 months of replacement therapy, is reported in about 1% of chronic dialysis patients. The role of personalized, intensive dialysis schedules and of resuming low‐protein diets has not been studied to date. This report describes three patients with RFR who were recently treated at a new dialysis unit set up to offer intensive hemodialysis. All three patients were females, aged 73, 75, and 78 years. Kidney disease included vascular‐cholesterol emboli, diabetic nephropathy and vascular and dysmetabolic disease. At time of RFR, the patients had been dialysis‐dependent from 3 months to 1 year. Dialysis was started with different schedules and was progressively discontinued with a “decremental” policy, progressively decreasing number and duration of the sessions. A moderately restricted low‐protein diet (proteins 0.6 g/kg/day) was started immediately after dialysis discontinuation. The most recent update showed that two patients are well off dialysis for 5 and 6 months; the diabetic patient died (sudden death) 3 months after dialysis discontinuation. Within the limits of small numbers, our case series may suggest a role for personalized dialysis treatments and for including low‐protein diets in the therapy, in enhancing long‐term RFR in elderly dialysis patients.     

Further experimental investigation of the correct Q1D electrodynamical part of a model for the fluid flow in a Faraday segmented MHD generator channel

In [1], the correct quasi-one-dimensional (Q1D) electrodynamical part (the electric current density vector in a working fluid has only one component: j_y) of a model for the fluid flow in a Faraday ideally segmented (absence of the Hall electric current: I_x = 0) generator channel was developed. In this paper, the validity of the model is demonstrated for the electric currents of interest for commercial MHD energy conversion with combustion products as a working fluid [3], and the semi-empirical factor †x from the model is further investigated.

It seems that in modeling in electrodynamics or electromagnetics the consequences of taking an assumption, better say a simplification, are the same as in fluid dynamics. By simplifying a problem we cut some of the connections of a model with reality, i.e. we partially destroy some of the equations and then they can be only partially satisfied. The most safe way to find, then, the connections left is to try to satisfy all the equations which can still be satisfied in the frame of the assumption(s) taken. In question are the models of fluid flow in a Faraday ideally segmented channel, which have the Q1D electrodynamical part as defined above, or based on the assumption that the x component (besides j_z = 0, E_z = 0) of the Faraday current j_x does not exist in the core of the flow, e.g. [3–6]. The assumption that the electric current flows inside a channel through the whole cross section of a segment (s2b), even in the core of the flow, does not correspond to reality [14]. It leads to an underestimation of the working fluid electrical resistance. One has to admit that in the frame of the assumption j_x = 0 it is impossible to describe the reality inside a channel. But, it is still possible to describe the global characteristics of a generator: electrical output, electrical and thermal efficiency, etc. with the Q1D model legitimate regarding the equation of conservation of charges (div j = 0 for the stationary electric current) [1].     

Support systems for the diffusion of renewable energy technologies—an investor perspective

Concern over climate change impacts and the projected depletion of fossil fuels has urged more governments to adopt policies that stimulate the diffusion of renewable energy technologies (RET). With an increasingly diverse suite of support instruments, the question emerges as to which instruments or combinations are able to achieve faster, more substantial diffusion results. Although various support instruments were extensively addressed in policy studies, there is still no consensus. This is partly because many policy studies take a policy-maker approach in comparing support instruments, leaving relationships between policy design and policy results as a black box. This paper proposes an investor-oriented perspective to analyze the diffusion potential of support systems for RET. The main argument is that it is not the type of support instrument but rather its risk/profitability characteristics that influence investor behavior and the rate of diffusion. The two instruments most frequently discussed and compared are the feed-in-tariff and the quota model. The analysis in this paper concludes that policy design is crucial: while often feed-in tariffs are applauded and quota system feared, feed-in tariffs may also bring about disappointing diffusion results when poorly designed while quota systems may be also conceived as attractive instruments for independent power producers.     

Adsorption characteristics of UO(2)(2+) and Th(4+) ions from simulated radioactive solutions onto chitosan/clinoptilolite sorbents

Adsorption features of UO(2)(2+) and Th(4+) ions from simulated radioactive solutions onto a novel chitosan/clinoptilolite (CS/CPL) composite as beads have been investigated compared with chitosan cross-linked with epichlorohydrin. The effects of contact time, the initial metal ion concentration, sorbent mass and temperature on the adsorption capacity of the CS-based sorbents were investigated. The adsorption kinetics was well described by the pseudo-second order equation, and the adsorption isotherms were better fitted by the Sips model. The maximum experimental adsorption capacities were 328.32 mg Th(4+)/g composite, and 408.62 mg UO(2)(2+)/g composite. The overall adsorption tendency of CS/CPL composite toward UO(2)(2+) and Th(4+) radiocations in the presence of Cu(2+), Fe(2+) and Al(3+), under competitive conditions, followed the order: Cu(2+)>UO(2)(2+)>Fe(2+)>Al(3+), and Cu(2+)>Th(4+)>Fe(2+)>Al(3+), respectively. The negative values of Gibbs free energy of adsorption indicated the spontaneity of the adsorption of radioactive ions on both the CS/CPL composite and the cross-linked CS. The desorption level of UO(2)(2+) from the composite CS/CPL, by using 0.1M Na(2)CO(3), was around 92%, and that of Th(4+) ions, performed by 0.1M HCl, was around 85%, both values being higher than the desorption level of radiocations from the cross-linked CS, which were 89% and 83%, respectively.     

Improved CO2 Capture from Flue Gas by Basic Sites,Charge Gradients,and Missing Linker Defects on Nickel Face Cubic Centered MOFs

The adsorptive properties of the isoreticular series [Ni₈(OH)₄(H₂O)₂(BDP_X)₆] (H₂BDP_X = 1,4‐bis(pyrazol‐4‐yl)benzene‐4‐X with X = H (1), OH (2), NH₂ (3)) can be enhanced by postsynthetic treatment with an excess of KOH in ethanol. In the case of X = H, NH₂, this treatment leads to partial removal of the organic linkers, deprotonation of coordinated water molecules and introduction of extraframework cations, giving rise to materials of K[Ni₈(OH)₅(EtO)‐(H₂O)₂(BDP_X)_5.5] (1@KOH, 3@KOH) formulation, in which the original framework topology is maintained. By contrast, the same treatment with KOH in the [Ni₈(OH)₄(H₂O)₂(BDP_OH)₆] (2) system, enclosing the more acidic phenol residues, leads to a new material containing a larger fraction of missing linker defects and extra‐framework cations as well as phenolate residues, giving rise to the material K₃[Ni₈(OH)₃(EtO)(H₂O)₆(BDP_O)₅] (2@KOH), which also conserves the original face cubic centered (fcu) topology. It is noteworthy that the introduction of missing linker defects leads to a higher accessible pore volume with a concomitant increased adsorption capacity. Moreover, the creation of coordinatively unsaturated metal centers, charge gradients, and phenolate nucleophilic sites in 2@KOH gives rise to a boosting of CO₂ capture features with increased adsorption heat and adsorption capacity, as proven by the measurement of pulse gas chromatography and breakthrough curve measurements of simulated flue gas.     

Identification of freshwater fish commercially labelled “perch” by isoelectric focusing and two-dimensional electrophoresis

Isoelectric focusing (IEF) and two-dimensional electrophoresis (2-DE) were used to distinguish four freshwater fish species which are sold under the generic label of “perch”: Perca fluviatilis (European perch), Lates niloticus (Nile perch), Stizostedion lucioperca (European pikeperch) and Morone chrysops x saxatilis (sunshine bass). These species have different commercial values but are easily “interchangeable” because they are sold already filleted, in view of the numerous bones of the whole fish. IEF of the water-soluble proteins extracted from fish muscle resolved in species-specific patterns. Intra-species polymorphism was low, and did not concern the bands identified as characteristic of the species. As well, 2-DE maps showed numerous species-specific protein spots. Interestingly, while none of the IEF bands was common to all four species, several major 2-DE spots were similar. Therefore, IEF of water soluble sarcoplasmic proteins is sufficient to unambiguously discriminate among the four species considered. Analysis by 2-DE, which has a higher resolution power but it is more expensive and time consuming, may be applied to obtain further knowledge of the proteome of poorly characterized species.     

Global and local processing of hierarchical visual stimuli in tufted capuchin monkeys (Cebus apella).

Capuchin monkeys' (Cebus apella) relative accuracy in the processing of the global shape or the local features of hierarchical visual stimuli was assessed. Three experiments are presented featuring manipulations of the arrangement and the density of the local elements of the stimuli. The results showed a clear advantage for local level processing in this species, which is robust under manipulations of the density of the local elements of the stimuli. By contrast, the density of the component elements linearly affected accuracy in global processing. These findings, which support those from other studies in which a local superiority emerged in animals, challenge the generality of early claims concerning the adaptive value of global advantage in the processing of hierarchical visual patterns. (PsycINFO Database Record (c) 2010 APA, all rights reserved)