Application of the revised EU criteria for the confirmation of anabolic steroids in meat using GC-MS

The EU criteria for the confirmation of the presence of illegal compounds in biological matrices were recently revised. The old and the revised criteria were applied to relative ion intensities obtained for five anabolic steroids (methylboldenone, methyltestosterone, ethynylestradiol, -boldenone and -nortestosterone) in meat (cow, pig, turkey) and fish at concentrations ranging from 0.5 to 5.0 g/kg. Confirmatory analysis was done by GC-MS; therefore four diagnostic ions had to be monitored and three ion ratios had to be calculated and tested against the criteria. Application of the old and revised criteria, with either standards or fortified samples as reference, showed mutually rather divergent results. Confirmation according to the revised EU criteria and using fortified samples as a reference gave the best results; in other words the highest percentage of diagnostic ion ratios within the tolerance intervals. A correlation was found between the percentage of these ion ratios and the signal/noise (S/N) ratio of the least intense ion of interest in the recorded MS spectrum. Although there were distinct differences in the results obtained for different analytes and sample types, it is safe to conclude that at S/N=3 the percentage of ratios within the tolerance intervals generally will be at or below 50%, while for S/N10, the percentage increases to over 90%. In the present study, fully satisfactory results were obtained down to about 2 g/kg, but not for lower analyte concentrations.     

Strictly ordered minimal subsets of a class of convex monotone skew-product semiflows

We study the topological and ergodic structure of a class of convex and monotone skew-product semiflows. We assume the existence of two strongly ordered minimal subsets and we obtain an ergodic representation of their upper Lyapunov exponents. In the case of null upper Lyapunov exponents, we obtain a lamination into minimal subsets of an intermediate region where the restriction of the semiflow is affine. In the hyperbolic case, we deduce the long-time behaviour of every trajectory ordered with K₂. Some examples of skew-product semiflows generated by non-autonomous differential equations and satisfying the assumptions of monotonicity and convexity are also presented.     

charge storage behavior of nanowire transistors functionalized with bis(terpyridine)-Fe(II) molecules: dependence on molecular structure

We studied the influence of three bis(terpyridine)-Fe(II) molecules-(X-tpy)2FeCl2 (X = H (1), SAc (2), and 4-phenyl-SAc (3)-on charge storage of a nanowire transistor. The molecules were assembled on the surface of an indium oxide nanowire that forms the conduction channel of the transistor. We found that the charge storage characteristics of such a device strongly depends on the structure of the terpyridine ligand: both retention time (tau) and threshold voltage shift (DeltaVth) increased in the order of 1 < 2 < 3, with tau of 200 s, 12 h, and 287 h and DeltaVth at 4.8, 12, and 28 V, respectively. Furthermore, when we placed the devices with molecules 1 and 3 in a vacuum and recorded the I-Vg curves in a two-day period, we observed higher hysteresis stability for device with molecule 3. For example, DeltaVth was reduced from 4.8 to 1.7 V for the device with molecule 1, while there was no reduction in DeltaVth for the device with molecule 2. These results suggest that thiolate headgroup and/or longer ligand length raises the charge tunneling barrier and results in longer charge retention and wider, more stable memory window. This work demonstrates the potential of chemical synthesis toward tailored device characteristics.     

State on splitting subspaces and completeness of inner product spaces

We show that an inner product spaceV is complete iff the system of all splitting subspaces, i.e., of all subspacesM for whichM + M =V, possesses at least one completely additive state.     

Reactions of π-cyclopentadienyltriphenylphosphinemetal diiodides and π-cyclopentadienylcarbonylmetal diiodides (M = Co,Rh, Ir) with 1,4-dilithio-1,2,3,4-tetraphenylbutadiene

Reactions between π-cyclopentadienyltriphenylphosphinemetàl diiodides (M = Rh and Ir) and 1,4-dilithio-l,2,3,4-tetraphenylbutadiene result in the formation of 1-(π-cyclopentadienyl)-l-triphenylphosphine-2,3,4,5-tetraphenylrhodole and 1-(π-cyclopentadienyl)-1-triphenylphosphine-2,3,4,5-tetraphenyliridole, respectively, in low yield. Reactions between π-cyclopentadienyltriphenylphosphinecobalt diiodide or π-cyclopentadienylcarbonylcobalt diiodide do not produce the expected cobaltacyclopentadiene complexes, but instead a low yield of π-cyclopentadienyl-(π-tetraphenylcyclobutadiene)cobalt. The trimeric rhodium complex (π-C₅H₅Rh)₃(CO)(PhCCPh) has been isolated from a reaction between 1,4-dilithio-l,2,3,4-tetraphenylbutadiene and π-cyclopentadienylcarbonylrhodium diiodide. The importance of metallocyclic intermediates in the formation of polynuclear complexes of this type is discussed.     

Test spaces,dacey spaces,and completeness of inner product spaces

We show that a test space consisting of the unit sphere of a real or complex inner product spaceS and of the set all maximal orthonormal systems inS, is algebraic iffS is Dacey or, equivalently, iffS is complete. In addition, we present another completeness criterion.This research is supported by the grant G-368 of the Slovak Academy of Sciences, Slovakia.     

Difference posets and the histories approach to quantum theories

Direct limits and tensor products of difference posets are studied. In the spirit of a recent paper by Isham, a potential model for an unsharp histories approach to quantum theory based on difference posets as abstract models for the set of effects is considered. It is shown that the set of all histories in this approach has an algebraic structure of a difference poset.     

Packing a convex domain with similar convex domains

Given a convex domain C and a positive integer k, inscribe k nonoverlapping convex domains into C, all of them similar to C. Denote by f(k) the maximal sum of their circumferences. In this paper it is shown, that for C square, parallelogram or triangle (1) the first increase of f(k) after k = l² occurs not later than at k = l² + 2, (2) constructions can be given, where the following lower bounds are attained for f(k) = f(l² + j):

$\text{(}\text{1}\text{c}\text{) ? l +}\text{(j ? 1)}\text{2l}\text{j}\text{odd}\text{, l? 2}$

$\text{? l +}\text{j}\text{2}\text{(l + 1) j}\text{even}\text{, l?2}$

where c denotes the circumference of C.     

Reactions involving transition metals: XX. A comparison of the reactions of 1,2,3,4,7,7-hexafluorobicyclo[2.2.1]heptadiene,and 2,3-bis(trimethyltin)- and 2,3-dichloro-1,4,5,6,7,7-hexafluorobicyclo[2.2.1]hepta-2,5-dienes with low valent transition metal complexes

1,2,3,4,7,7-Hexafluorobicyclo[2.2.1]heptadiene (1) and 2,3-bis(trimethyltin)-1,4,5,6,7,7-hexafluorobicyclo[2.2.1]hepta-2,5-diene (2) react with [M(Ph₃P)₄] (M = Pt, Pd) to afford air-stable adducts. 2,3-Dichloro-1,4,5,6,7,7-hexafluorobicyclo[2.2.1]hepta-2,5-diene (3) gives only [PtCl₂(PPh₃)₂] with [Pt(Ph₃P)₄], but a low yield of an adduct was obtained with [Pd(PPh₃)₄]. The diene 1 also reacts with Fe(CO)₅ to form the complex [(C₇H₂F₆)Fe(CO)₄], and with [Rh(C₂H₄)₂(acac)] to give [(C₇H₂F₆)Rh(acac)] in which the diene acts as a bidentate ligand. Similar products could not be isolated from the reactions of 2 and 3. A stable adduct, believed to be [{C₇F₆(SnMe₃)₂}Rh(CO)₂(μ-Cl)₂Rh(CO)₂] has been isolated from the reaction between 2 and [Rh(CO)₂Cl]₂. This adduct reacts with PPh₃ to give the bridge-cleavage product [{C₇F₆(SnMe₃)₂}RhCl(CO)(PPh₃)₂]. Reaction of 1 with [Rh(CO)₂Cl]₂ gives an unstable adduct which could not be isolated, and 2 does not react at room temperature. The chloro derivative 3 reacts with [PdCl₂(PhCN)₂] to give the adduct [(C₇F₆Cl₂)PdCl(PhCN)], but 1 and 2 do not react under similar conditions. Stable substitution products [(C₇F₆R₂)M] (R = H, M = Fe(CO)₂(η-C₅H₅); R = SnMe₃, M = Fe(CO)₂(η-C₅H₅), Mn(CO)₅, Ir(CO)₂(PPh₃)₂, Rh(CO)₂(PPh₃)₂; R = Cl, M = Ir(CO)₂(PPh₃)₂, Rh(CO)₂(PPh₃)₂) have been isolated from the reactions of the dienes with carbonylmetal anions. Insertion of the CHCH bond occurs when 1 is heated with [MnMe(CO)₅] to give [{C₇F₆H₂C($\text{O)Me}M}$n(CO)₄], and this, on reaction with either PPh₃ or [Pt(PPh₃)₄], gives [(C₇F₆H₂COMe)Mn(CO)₄PPh₃].     

Use of a gas-sensor array for detecting volatile organic compounds (VOC) in chemically induced cells

An application of gas sensors for rapid bioanalysis is presented. An array of temperature-modulated semiconductor sensors was used to characterize the headspace above a cell culture. Recombinant Saccharomyces cerevisiae yeast cells, able to respond to 17-estradiol by producing a reporter protein, were used as a model system. Yeast cells had the DNA sequence of the human estrogen receptor stably integrated into the genome, and contained expression plasmids carrying estrogen-responsive sequences and the reporter gene lac-Z, encoding the enzyme -galactosidase. The sensor-response profiles showed small but noticeable discrimination between cell samples induced with 17-estradiol and non-induced cell samples. The sensor array was capable of detecting changes in the volatile organic compound composition of the headspace above the cultured cells, which can be associated with metabolic changes induced by a chemical compound. This finding suggests the possibility of using cross-selective gas-sensor arrays for analysis of drugs or bioactive molecules through their interaction with cell systems, with the advantage of providing information on their bioavailability.