Lengths for Which Fourth Degree PP Interleavers Lead to Weaker Performances Compared to Quadratic and Cubic PP Interleavers

In this paper, we obtain upper bounds on the minimum distance for turbo codes using fourth degree permutation polynomial (4-PP) interleavers of a specific interleaver length and classical turbo codes of nominal 1/3 coding rate, with two recursive systematic convolutional component codes with generator matrix G=[1,15/13]. The interleaver lengths are of the form 16Ψ or 48Ψ, where Ψ is a product of different prime numbers greater than three. Some coefficient restrictions are applied when for a prime pi∣Ψ, condition 3∤(pi−1) is fulfilled. Two upper bounds are obtained for different classes of 4-PP coefficients. For a 4-PP f4x4+f3x3+f2x2+f1x(mod16kLΨ), kL∈{1,3}, the upper bound of 28 is obtained when the coefficient f3 of the equivalent 4-permutation polynomials (PPs) fulfills f3∈{0,4Ψ} or when f3∈{2Ψ,6Ψ} and f2∈{(4kL−1)·Ψ,(8kL−1)·Ψ}, kL∈{1,3}, for any values of the other coefficients. The upper bound of 36 is obtained when the coefficient f3 of the equivalent 4-PPs fulfills f3∈{2Ψ,6Ψ} and f2∈{(2kL−1)·Ψ,(6kL−1)·Ψ}, kL∈{1,3}, for any values of the other coefficients. Thus, the task of finding out good 4-PP interleavers of the previous mentioned lengths is highly facilitated by this result because of the small range required for coefficients f4,f3 and f2. It was also proven, by means of nonlinearity degree, that for the considered inteleaver lengths, cubic PPs and quadratic PPs with optimum minimum distances lead to better error rate performances compared to 4-PPs with optimum minimum distances.

Temporal variability in urinary excretion of bisphenol A and seven other phenols in spot, morning, and 24-h urine samples

Human exposure to modern non-persistent chemicals is difficult to ascertain in epidemiological studies as exposure patterns and excretion rates may show temporal and diurnal variations. The aim of this study was to assess the temporal variability in repeated measurements of urinary excretion of bisphenol A (BPA) and seven other phenols. All analytes were determined using TurboFlow-LC-MS/MS. Two spot, three first morning and three 24-h urine samples were collected from 33 young Danish men over a three months period. Temporal variability was estimated by means of intraclass correlation coefficients (ICCs). More than 70% of the urine samples had detectable levels of BPA, triclosan (TCS), benzophenone-3 (BP-3) and sum of 2,4-dichlorophenol and 2,5-dichlorophenol (ΣDCP). We found low to moderate ICCs for BPA (0.10-0.42) and ΣDCP (0.39-0.72), whereas the ICCs for BP-3 (0.69-0.80) and TCS (0.55-0.90) were higher. The ICCs were highest for the two spot urine samples, which were collected approximately 4 days apart, compared with the 24-h urine samples and the first morning urine samples, which were collected approximately 40 days apart. A consequence of the considerable variability in urinary excretion of BPA may be misclassification of individual BPA exposure level in epidemiological studies, which may lead to attenuation of the association between BPA and outcomes. Our data do not support that collection of 24-h samples will improve individual exposure assessment for any of the analysed phenols.

Synthesis and biological evaluation of novobiocin analogues as potential heat shock protein 90 inhibitors

Recent studies have shown that novobiocin (NB), a member of the coumermycin (CA) family of antibiotics with demonstrated DNA gyrase inhibitory activity, inhibits Heat shock protein 90 (HSP90) by binding weakly to a putative ATP-binding site within its C-terminus. To develop more potent HSP90 inhibitors that target this site and to define structure-activity relationships (SARs) for this class of compounds, we have synthesized twenty seven 3-amido-7-noviosylcoumarin analogues starting from NB and CA. These were evaluated for evidence of HSP90 inhibition using several biological assays including inhibition of cell proliferation and cell cycle arrest, induction of the heat shock response, inhibition of luciferase-refolding in vitro, and depletion of the HSP90 client protein c-erbB-2/HER-2/neu (HER2). This SAR study revealed that a substantial increase in biological activity can be achieved by introduction of an indole-2-carboxamide group in place of 4-hydroxy-isopentylbenzamido group at C-3 of NB in addition to removal/derivatization of the 4-hydroxyl group from the coumarin ring. Methylation of the 4-hydroxyl group in the coumarin moiety moderately increased biological activity as shown by compounds 11 and 13. Our most potent new analogue 19 demonstrated biological activities consistent with known HSP90-binding agents, but with greater potency than NB.

Urinary excretion of phthalate metabolites, phenols and parabens in rural and urban Danish mother-child pairs

Some phthalates, parabens and phenols have shown adverse endocrine disrupting effects in animal studies and are also suspected to be involved in human reproductive problems. However, knowledge about exposure sources and biomonitoring data in different subsets of populations are still scarce. Thus, in this study first morning urine samples were collected from 6 to 11 years Danish children and their mothers. The content of seven parabens, nine phenols and metabolites of eight different phthalates were analysed by LC-MS/MS. Two parabens, six phenols and metabolites from six phthalate diesters were measurable in more than 50%, 75% and 90% of the participants, respectively. Thus the children and their mothers were generally exposed simultaneously to a range of phthalates, phenols and parabens. In general, the levels were low but for several of the compounds extreme creatinine adjusted concentrations 100-500-fold higher than the median level were seen in some participants. Children were significantly higher exposed to bisphenol A (BPA) and some of the phthalates (DiBP, DnBP, BBzP, DEHP and DiNP) than their mothers, whereas mothers were higher exposed to compounds related to cosmetics and personal care products such as parabens (MeP, EtP and n-PrP), benzophenone-3, triclosan and diethyl phthalate. However, a very high correlation between mothers and their children was observed for all chemicals. A high individual exposure to one chemical was often associated with a high exposure to other of the chemicals and the possibility of combination effects of multiple simultaneous exposures cannot be excluded.