On the fundamentals of extended thermodynamics (ET) of a one-dimensional rarefied gas

Extended thermodynamics (ET) of degreer for a one-dimensional rarefied gas based, by definition, on a finite set A^r={a⁰, a²,..., a^r} of the firstr–1(3r) direct internal moments of the one-point distribution functionf is carefully investigated. With the aid of the second axiom of thermodynamics, the new representation forf, depending in a local and nonlinear way onA ^r , is explicitly derived. It is demonstrated that in ET of degreer an infinite sequence {b^r+1, b^r+2,...} ofhigher order Hermite coefficients, which normally drops out of Grad's proposition forf fashioned by mathematical apparatus such as the Hermite polynomials, cannot be considered negligible in the case when nonlinear constitutive functions are established. Using Ma's kinetic equation corresponding to a one-dimensional rarefied gas as well as the generalized representation forf, collision productions in the nonconservative moment equations are then calculated for a special choice of the rate of collisions between particles.     

Ion transport across model lipid membranes containing light-harvesting complex II: an effect of light

The effect of light on proton transport across lipid membranes of small unilamellar liposomes containing incorporated major light-harvesting pigment-protein complex of Photosystem II (LHCII) has been studied with the application of pH-sensitive dyes entrapped inside vesicles. Proton permeability coefficient for LHCII-modified membranes was found to be about twice as high as in the case of the control pure lipid vesicles. Illumination of the samples with light absorbed by the LHCII-bound photosynthetic pigments considerably affects the kinetics of proton transport: it increases the rate and decreases the steady-state level of proton gradient across the membranes. The effect was interpreted in terms of heat-induced conformational changes of LHCII molecular structures that affect proton buffering capacity of this protein. Both the control and the LHCII-modified lipid membranes have been found to be practically impermeable to Ca(++) ions, as demonstrated by fluorescence of liposome-entrapped calcium-sensitive probe calcium crimson. The slight differences in the proton transport across the LHCII-containing membranes under the presence of Ca(++) suggest calcium binding to this antenna protein.     

On stability of the Cauchy equation on semigroups

Summary We say that Hyers's theorem holds for the class of all complex-valued functions defined on a semigroup (S, +) (not necessarily commutative) if for anyf:S such that the set {f(x + y) – f(x) – f(y): x, y S} is bounded, there exists an additive functiona:S for which the functionf – a is bounded.Recently L. Székelyhidi (C. R. Math. Rep. Acad. Sci. Canada8 (1986) has proved that the validity of Hyers's theorem for the class of complex-valued functions onS implies its validity for functions mappingS into a semi-reflexive locally convex linear topological spaceX. We improve this result by assuming sequential completeness of the spaceX instead of its semi-reflexiveness. Our assumption onX is essentially weaker than that of Székelyhidi. Theorem.Suppose that Hyers's theorem holds for the class of all complex-valued functions on a semigroup (S, +) and let X be a sequentially complete locally convex linear topological (Hausdorff) space. If F: S X is a function for which the mapping (x, y) F(x + y) – F(x) – F(y) is bounded, then there exists an additive function A : S X such that F — A is bounded.     

Possible role of hydrolytic enzymes (Sap,Kex2) in <Emphasis Type="Italic">Candida albicans</Emphasis> response to aromatic compounds bearing a sulfone moiety

Hydrolytic enzymes e.g., Saps and Kex2 are, due to their role in Candida virulence, considered important targets for new synthetic inhibitors. MICTI and MICPI values indicate that disruption of SAP1-3 significantly increases the resistance of Candida mutants to β-ketosulfone (1). Contrariwise, sap123Δ showed sensitive phenotype to halogenated methylphenyl sulfone (2). Anticandidal potency of 2 differed in the Candida cells of kex2Δ. Sulfone is the most effective agent against the Candida albicans kex2Δ double mutant (MICTI of 0.5 µg mL^?1). Up-regulation of KEX2 mediated the resistance of sap4-6Δ towards 2. Both sulfones tested reduced the adhesion of the wild type cells significantly (P ≤ 0.05). Contrariwise, sap123Δ showed significantly enhanced adhesion capability when 1 was used (P ≤ 0.05). Both sulfones had weak fungicidal effect on mature C. albicans biofilms. It was shown that the uptake of IP correlates with the membrane perturbations caused by 1 in the blastoconidial cells. Sulfones were found to disturb the basic developmental phases of biofilm growth: adhesion and morphogenesis. Altered KEX2 levels for 1 can be caused by the compensatory mechanism for the maintenance of cell wall integrity and morphogenesis. KEX2 decreases the antifungal activity of sulfones. Sulfones affecting the crucial virulence factors of Candida can even eliminate these fungal infections.     

Counting signed swallowtails of polynomial selfmaps of {\mathbb {R}^3}

For a generic \({f \in C^\infty({\mathbb {R}}^3,{\mathbb {R}}^3)}\), there is a discrete set of swallowtail critical points. At any swallowtail point p there exists a well-oriented coordinate system centred at p, and a coordinate system centred at f(p), such that locally f has the form \({f_\pm(x, y, z) = (\pm xy+x^2 z+x^4, y, z)}\), so one may associate with p a sign \({I(f, p) \in \{\pm 1\}}\). We shall show how to compute the number of swallowtail points having the positive/negative sign, in the case where \({f : {\mathbb {R}}^3 \rightarrow {\mathbb {R}}^3}\) is a polynomial mapping, in terms of signatures of quadratic forms.     

Fabrication and dielectric properties of modified calcium (Pb<Subscript>0.75</Subscript>Ba<Subscript>0.25</Subscript>)(Zr<Subscript>0.7</Subscript>Ti<Subscript>0.3</Subscript>)O<Subscript>3</Subscript> ceramics

The aim of the present work is to report investigations concerning the influence of homovalent modificators on relaxor properties of PBZT 25/70/30 ceramics. The selection of the proper homovalent additive was very important. Literature reports as well as data taken from the periodic table indicated, that calcium ions substitute themselves for lead ions with high likelihood of occurrence. The investigations showed that the substitution significantly changed the microstructure of ceramics – with grains of calcium modified ceramics decreasing and density increasing. The XRD measurements indicate that the pure PBZT ceramics as well as calcium dopant were characterised by tetragonal structure with space group I4 /mmm. Addition of calcium leads to a slight decrease in the lattice constant and crystal structure. The calcium modification also changes the dielectric properties. The temperature characteristic of the dielectric constant achieved a broadened maximum at temperature T_m, which decreases with increasing Ca content. The properties typical for ferroelectric relaxors weaken with increasing calcium dopant.     

The Cu2SO2 phase

The conditions of synthesis of the Cu₂SO₂ phase, its thermal characteristics and its reactivity with respect to some other phases occurring in the Cu-S-O system below 710 K, at \(P_{SO_2 } \) =101 kPa, have been given. It has been established that the phase undergoes two reversible solid-state transitions, melts without decomposition at 610 K, and in the liquid state is stable up to 680 K. It is pointed out that Cu₂SO₂ is a phase thermally more stable than Cu₂SO₄.     

An approach to a new class of selenosugars : A convenient synthesis of glycosyl isoselenocyanates

A new class of selenosugars—glycosyl isoselenocyanates—has been prepared via reaction of the corresponding glycosyl isocyanides with elemental Se under the catalytic influence of triethylamine. 2,3,4,5,6-Penta-O-acetyl-D-gluconyl isoselenocyanate was also prepared in moderate yield by reaction of 2,3,4,5,6-penta-O-acetyl-D-gluconyl chloride with potassium selenocyanate in anhydrous acetone. The isoselenocyanate structure is ascertained by physical (¹³C-NMR, IR) and chemical methods—formation of selenoureas, and radical induced fragmentation by reaction with tri-n-butyltin hydride via intermediate isocyanide, to 1,5-anhydro-D-hexitols.     

New distannanes containing the chiral 2-(4-isopropyl-2-oxazolinyl)-5-phenyl ligand

The N-coordinated tin hydrides containing the chiral 2-(4-isopropyl-2-oxazolinyl)-5-phenyl ligand in the presence of catalytic amounts of tetrakis(triphenylphosphine)palladium gave the corresponding distannanes in good yields. The distannanes have been fully characterized by means of the ¹H, ¹³C, ¹⁵N and ¹¹⁷Sn NMR measurements. The J(¹⁵N-^117/119Sn), J(¹¹⁷Sn-¹¹⁹Sn) couplings and single-crystal X-ray analysis of distannane 3 revealed a tendency towards penta-coordination at the tin center as a result of the Sn-N interaction.     

High power electron accelerators for flue gas treatment

Over 1000 accelerators based on different principles have been constructed and used in the field of radiation chemistry and radiation processing. One of the radiation processes which was successfully demonstrated in many laboratories and pilot plant facilities is the reduction of SO₂ and NO_x pollutants from flue gases emitted during fuel combustion in boilers for electrical power and heat production. The full scale industrial implementation of an electron beam process for flue gases treatment would require accelerator modules with a beam power of over 500 kW and electron energy in the range 1–1.5 MeV. The 500 MW power plant may require 5–8 MW of electron beam power deposited in the flue gas.