On the extensions of homogeneous polynomials

We investigate the problem of the uniqueness of the extension of -homogeneous polynomials in Banach spaces. We show in particular that in a nonreflexive Banach space that admits contractive projection of finite rank of at least dimension 2, for every there exists an -homogeneous polynomial on that has infinitely many extensions to . We also prove that under some geometric conditions imposed on the norm of a complex Banach lattice , for instance when satisfies an upper -estimate with constant one for some , any -homogeneous polynomial on attaining its norm at with a finite rank band projection , has a unique extension to its bidual . We apply these results in a class of Orlicz sequence spaces.

     

Interference of acute cigarette smoking with [¹³C]methacetin breath test

It is essential to establish whether and how environmental factors affect the reliability of [(13)C]methacetin breath test ((13)C-MBT). In 12 healthy volunteers (smokers), a standard (13)C-MBT with 75 mg [(13)C]methacetin was performed twice in random order: on a control day without smoking and on another day with smoking two cigarettes antecedently. A considerable flattening of the curve of the momentary (13)C recovery within the expiratory air was observed when the (13)C-MBT was performed after smoking. The maximum of the momentary (13)C recovery, D(max), decreased from 37.20±2.58 to 25.39±2.29% dose/h (p=0.00052). Moreover, the time to reach D(max) was prolonged after cigarette smoking (26.5±3.1 vs. 16.5±1.9 min, p=0.0199). The curve of the cumulative (13)C recovery on the cigarette smoking day appeared to be shifted downwards, and statistically significant differences relative to the control situation were found between the 24th and 75th minute following [(13)C]methacetin administration. Smoking cigarettes immediately prior to the (13)C-MBT diminishes the ability of the liver to handle methacetin, and hence a possibility of such an interaction should be excluded in order to interpret the results of the test correctly.     

The growth kinetics of colloidal ZnO nanoparticles in alcohols

We have studied the synthesis of ZnO nanostructures over a wide range of parameters to determine the kinetics of the nanocrystals growth. The initial rapid nucleation and growth is kinetically controlled, the subsequent ZnO nanocrystals growth is thermodynamically controlled through the diffusion limited Ostwald coarsening. The ZnO coarsening rates increased with number of alcohol’s alkyl group carbons and temperature increase, pointing to importance of the solvent viscosity, dielectric constants, surface energy and the bulk solubility. The results are consistent with the Lifshitz–Slyozov–Wagner model. For all alcohols, in the NaOH induced reaction, a lower activation energy was observed compared to the aqueous reaction. A lower ZnO solubility, obtained by the water synthesis could be responsible for these observations. Our results point to the importance of the reactant selection in controlling the kinetics of the nanostructure formation, their size and the nature of the surface defects responsible for their luminescence.     

In–Ga–Zn–O MESFET with transparent amorphous Ru–Si–O Schottky barrier

Rectifying transparent amorphous Ru–Si–O Schottky contacts to In–Ga–Zn–O have been fabricated by means of reactive sputtering without any annealing processes nor semiconductor surface treatments. The ideality factor, effective Schottky barrier height and rectification ratio are equal to 1.6, 0.9 eV and 10⁵ A/A, respectively. Ru–Si–O/In–Ga–Zn–O Schottky barriers were employed as gate electrodes for In–Ga–Zn–O metal–semiconductor field‐effect transistors (MESFETs). MESFET devices exhibiting on‐to‐off current ratio at the level of 10³ A/A in a voltage range of 2 V, with subthreshold swing equal to 420 mV/dec were demonstrated. A channel mobility of 7.36 cm²/V s was achieved. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Are generalized Lorentz ``spaces' really spaces?

We show that the Lorentz space need not be a linear set for certain ``non-classical" weights . We establish necessary and sufficient conditions on and for this situation to occur.

     

Application of the laser ablation for conservation of historical paper documents

Laser ablation was applied for surface cleaning and spectroscopic diagnostics of historical paper documents and model samples in the framework of the conservation projects. During cleaning the spectra of ablation products were recorded by means of the LIBS technique which allowed for nearly non-destructive identification of surface layers such as contaminants, substrate and pigments. For consecutive laser pulses a strong decrease of band intensities of the emission lines of Ca, Na, K, Al and Fe ascribed to contaminants were observed. The effect was used for monitoring of the cleaning progress of stained paper. For surface cleaning and spectra excitation the Q-switched Nd:YAG laser of 6 ns pulsewidth operating at wavelengths of 266, 355, 532, and 1064 nm and of fluence selected from the range 0.3-0.9 J/cm² was applied. The ablation parameters were optimized in agreement with the literature and the results were confirmed by surface studies and testing of the mechanical and chemical properties, and also by the response to the ageing process of the paper substrate. In case of the model paper irradiated in the UV range at 266 and 355 nm a visual inspection revealed local damages of the cellulose fibers accompanied by a decrease of the mechanical strength of the substrate. The effect was more pronounced after artificial ageing. The best results were obtained for samples irradiated at 532 nm and at laser fluence below the damage threshold of 0.6 J/cm², which is in agreement with literature.     

Bola-Amphiphilic Glycodendrimers: New Carbohydrate-Mimicking Scaffolds to Target Carbohydrate-Binding Proteins

Dendrimers are appealing scaffolds for creating carbohydrate mimics with unique multivalent cooperativity. We report here novel bola-amphiphilic glycodendrimers bearing mannose and glucose terminals, and a hydrophobic thioacetal core responsive to reactive oxygen species. The peculiar bola-amphiphilic feature enabled stronger binding to lectin compared to conventional amphiphiles. In addition, these dendrimers are able to target mannose receptors and glucose transporters expressed at the surface of cells, thus allowing effective and specific cellular uptake. This highlights their great promise for targeted delivery.