Energy independent number of clusters and multiplicity distribution at Collider and beyond

Multiplicity distributions up to the Collider energies could be described by various two-parameter compounded distributions having in common Poisson distributed number of clusters. Among them the logarithmic distribution for hadronization via decaying clusters leads to energyindependent number of clusters above the ISR energies, replacing the previous KNO-scaling.Dedicated to the 30th anniversary of the Joint Institute for Nuclear Research.     

On quadratic and sesquilinear functionals

LetX be a leftA-module, whereA is either a complex Banach *-algebra with an identity element or the field of quaternions. The main result of this note is that forQ, anA-quadratic functional defined onX, there exists a sesquilinear functionalB such thatB(x,x)=Q(x) holds for allxX.     

On a construction of Thomassen

Using a construction of Thomassen [Discrete Math. 9, 91–96 (1974)] we prove that for infinitely manyn there is a family _n of triangle-free maximally non-hamiltonian graphs of ordern with | _n | exponentially inn. In particular, for everym 48 we construct such a graph; an infinite number of these provide new almost extremal examples in the sense of minimal size.     

Synthesis and structure of trigonal and tetragonal connectors for a "Tinkertoy" construction set

We describe a convergent synthesis of eight 1,3,5- and 1,2,4,5-substituted benzene derivatives with long rigid arms containing 4-pyridyl, 2,2'-bipyridyl, and 2,2'-bipyrimidyl termini, meant to be used as trigonal or tetragonal connectors for the construction of large molecular structures. The synthesis involved copper-free Pd-mediated coupling of terminal acetylenes to aryl halides. First, one of the termini of 1,3-diethynylbicyclo[1.1.1]pentane was coupled with a brominated aza heterocycle, and second, 3 equiv of the resulting extended arm were coupled with 1,3,5-triiodobenzene or 4 with 1,2,4,5-tetraiodobenzene. An improved large-scale synthesis for 1,3-diethynylbicyclo[1.1.1]pentane is described. The structures of two of the arms were determined by single-crystal X-ray analysis. Several long molecular rods with 4-pyridyl termini were obtained as byproducts, and a single-crystal X-ray structure is reported for the shortest of these.     

Infrared spectroscopic study of the structure of the tetrabutyl S-dithiopyrophosphate complex of silver

The structure of the complex Ag·TBDTPP (tetrabutyl S-dithiopyrophosphate) formed in HNO₃ medium was studied by IR and NMR methods. The complex is involved in the isomerization of TBDTPP in the presence of Ag⁺ and NO ₃ ⁻ ions. In the IR spectra, we observe the disappearance of P−O−P band and the occurrence of new absorption bands associated with P−S−P and P=O bonds. The silver ion is coordinated to the thiophosphoryl group of the isomer molecule. The influence of HNO₃ concentration on complex formation is discussed.     

Isoperichoric focusing field-flow fractionation and thin layer isoperichoric focusing based on coupling of gradient generated by primary field with secondary field action: general principles and performances

The primary field forces can generate spatially oriented gradient of the effective property of a continuum or pseudo-continuum fluid (carrier liquid). When this gradient is coupled with the action of a secondary field of identical or different nature the isoperichoric focused zones of the dispersed species can appear. Consequently, they can be separated according to differences responding to the property gradient of the carrier liquid. This concept can be applied under static (non-flow) conditions in thin layer focusing as well as under dynamic conditions with the elution due to the carrier liquid flow in focusing field-flow fractionation. The gradient established by the action of the primary field and the concentration distribution of the isoperichoric focused zone formed by the coupled effect of the gradient and of the primary or secondary field are described theoretically. The rigorous relationship describing the shape of the focused zone is compared with the approximate solutions. The performances of the proposed principle were evaluated by model calculations. Potential experimental configurations considering the implementation of the static and dynamic conditions are discussed. The generalized isoperichoric focusing theory can be applied to describe the particular processes operating in analytical and preparative focusing separations of the particles of various, but especially of biological origin.     

Gel permeation chromatographic characterization of sodium hyaluronate and its fractions prepared by ultrasonic degradation

Summary High-molecular-weight sodium hyaluronate isolated from rooster combs was degraded by ultrasonication. The molecular weight of hyaluronate and its polydispersity was determined by gel-permeation chromatography. During 75-min treatment the molecular weight value decreased from 1.39×10⁶ Da to 2.25×10⁵ Da while the polydispersity of the molecular weight increased from 1.29 to 2.36. The reciprocal value of the square of the hyaluronate's molecular weight was linearly proportional to the time of ultrasonication.     

Size exclusion chromatographic characterization of sodium hyaluronate fractions prepared by high energetic sonication

Summary A high molecular weight sodium hyaluronate isolated from rooster combs was degraded by ultrasonication. High-performance size exclusion chromatography allowed rapid and accurate determination of molecular weight parameters (M_z, M_w, M_n) and distributions. The time dependence of hyaluronan ultrasonication to the molecular characteristics of the polymer was investigated. A non-random nature of the degradation process was demonstrated and the reciprocal M_n value was found to be linearly proportional to the time of ultrasonication.     

Precipitation separation of lead and calcium,strontium, barium from acidic solutions using crown ether and tungstosilicic acid

It was found that lead reacts with 18-crown-6 (L) and tungstosilicic acid (H₄A) in acidic solutions and a compound with low solubility is formed what was confirmed by radiometric titration methods. Coprecipitation of complexion cation of PbL²⁺ with similar complexion cations of calcium, strontium and barium was studied. Formation of low soluble salts was utilized for separation of Pb from Ca, Sr and Ba from 1 mol·dm^–3 HNO₃. The ratio of Pb/Ca, Pb/Sr and Pb/Ba in the precipitation or separation factors S_pb/M undoubted depends on the ratio of the stability constants of lead and metals with 18C6 (_Pb/_M), what can be used for determination of more precise constant stability _M.