COX Inhibitory and Cytotoxic Naphthoketal-Bearing Polyketides from Sparticola junci

Axenic fermentation on solid rice of the saprobic fungus Sparticola junci afforded two new highly oxidized naphthalenoid polyketide derivatives, sparticatechol A (1) and sparticolin H (2) along with sparticolin A (3). The structures of 1 and 2 were elucidated on the basis of their NMR and HR-ESIMS spectroscopic data. Assignment of absolute configurations was performed using electronic circular dichroism (ECD) experiments and Time-Dependent Density Functional Theory (TDDFT) calculations. Compounds 1–3 were evaluated for COX inhibitory, antiproliferative, cytotoxic and antimicrobial activities. Compounds 1 and 2 exhibited strong inhibitory activities against COX-1 and COX-2. Molecular docking analysis of 1 conferred favorable binding against COX-2. Sparticolin H (2) and A (3) showed a moderate antiproliferative effect against myelogenous leukemia K-562 cells and weak cytotoxicity against HeLa and mouse fibroblast cells.     

HgCdTe sampling circuit

The demonstration, using HgCdTe MISFETs, of a sampling circuit with output buffer amplifier is reported. Using the circuit, correlated double sampling is demonstrated at speeds typical of those required for focal plane arrays. Using a swept sine input, the circuit's transfer function is verified. The circuit was fabricated on epitaxially grown HgCdTe, with a cutoff wavelength of 3.56 mu m at 77 K.<>     

A concept for inferring ‘frontier research’ in grant proposals

This paper discusses a concept for inferring attributes of ‘frontier research’ in peer-reviewed research proposals under the popular scheme of the European Research Council (ERC). The concept serves two purposes: firstly to conceptualize, define and operationalize in scientometric terms attributes of frontier research; and secondly to build and compare outcomes of a statistical model with the review decision in order to obtain further insight and reflect upon the influence of frontier research in the peer-review process. To this end, indicators across scientific disciplines and in accord with the strategic definition of frontier research by the ERC are elaborated, exploiting textual proposal information and other scientometric data of grant applicants. Subsequently, a suitable model is formulated to measure ex-post the influence of attributes of frontier research on the decision probability of a proposal to be accepted. We present first empirical data as proof of concept for inferring frontier research in grant proposals. Ultimately the concept is aiming at advancing the methodology to deliver signals for monitoring the effectiveness of peer-review processes.     

Web networks of the science system: Weighted hubs and authorities

Summary Visualization with the algorithm of BibTechMon provides the out-degree as well as the in-degree. The analysis shows that both frequency and co-occurrences of objects (nodes in the network) support the idea of Kleinberg's algorithm. The analysis of the algorithm shows clearly that strongly linked scores lead the iteration to a convergence and give the highest weights. Therefore BibTechMon visualizes the results well.     

Carnot-COP for sorption heat pumps working between four temperature levels

The theoretical efficiency limits of heat driven heat pumps operating between three and four temperatures are derived from the fundamental thermodynamical laws, i.e. the energy balance and the entropy balance. While in the three temperatures case the system is fully determined by specification of the three temperatures and the cooling capacity, a four temperature heat pump needs, in addition to the four temperatures and the cooling capacity, specification of an additional operating parameter. This can be, for example, the ratio of the two heat flows which are released at the two different intermediate temperatures. Various assumptions regarding this proportion are discussed with respect to their relevance for both the combination power cycle/vapor compression cycle as well as for single-effect sorption cycles. The present analysis shows that a single-effect sorption heat pump is principally not able to operate reversibly in an environment of four externally specified temperatures unless the four temperatures follow, incidentally, a correlation that is given by the equilibrium properties of the employed working fluids. Therefore, in endo-reversible models for four-temperature sorption cycles only three rather than four operating temperatures may be specified independently.     

Efficient, high-spectral-resolution Bragg crystal x-ray polarimeter

Utilizing Bragg scattering near 90 degrees , an x-ray polarimeter is described that has high spectral resolution and reasonable efficiency. The latter is achieved by using a position-sensitive proportional counter to discriminate spatially resolved x rays dispersed by the crystal. This instrument has been used to measure the linear polarization of lines from one- and two-electron oxygen ions. For this study, aligned initial states have been populated in oxygen beams by various excitation processes in foil, gas, and thick solid targets. In spite of the small probability for the production and radiative decay of few-electron excited states in the presence of intense background radiation, the instrument resolution and efficiency are sufficient to permit polarization measurements.     

Visualization of research fronts and knowledge bases by three-dimensional areal densities of bibliographically coupled publications and co-citations

In this work the well known scientometric concepts of bibliographically coupled publications and co-cited references were applied to produce interactive maps of research fronts and knowledge bases of research fields. This article proposes a method and some standardization for the detection and visualization of research fronts and knowledge bases with two and three dimensional graphics inspired by geographical maps. Agglomerations of bibliographically coupled publications with a common knowledge base are identified and graphically represented by a density function of publications per area unit. The research fronts become visible if publications with similar vectors of common citations are associated and visualized as an ensemble in a three dimensional graphical representation as a mountain scenery measured with the help of a spatial density. Knowledge bases were calculated in the same way. Maps similar to the geographic representation of oceans and islands are used to visualize the two-dimensional spatial density function of references weighted by individual links. The proposed methodology is demonstrated by publications in the field of battery research.     

A model for 1/f noise in diffusion current based on surfacerecombination velocity fluctuations and insulator trapping

In this paper we present a new model for low frequency 1/f noise in semiconductor diodes. The model describes noise in diffusion current due to fluctuations in surface recombination velocity. The fluctuations in surface recombination velocity are in turn caused by insulator trapping. We examine the model's predictions for 1/f noise and its dependence on device geometry, temperature, surface potential, majority carrier concentration, and trap energy. Example calculations are performed for narrow band gap HgCdTe (E_G=0.125 eV at 77 K), for which this mechanism should be relevant     

A selective difference between human Y-chromosomal DNA haplotypes

DNA analysis is making a valuable contribution to the understanding of human evolution [1]. Much attention has focused on mitochondrial DNA (mtDNA) [2] and the Y chromosome [3] [4], both of which escape recombination and so provide information on maternal and paternal lineages, respectively. It is often assumed that the polymorphisms observed at loci on mtDNA and the Y chromosome are selectively neutral and, therefore, that existing patterns of molecular variation can be used to deduce the histories of populations in terms of drift, population movements, and cultural practices. The coalescence of the molecular phylogenies of mtDNA and the Y chromosome to recent common ancestors in Africa [5] [6], for example, has been taken to reflect a recent origin of modern human populations in Africa. An alternative explanation, though, could be the recent selective spread of mtDNA and Y chromosome haplotypes from Africa in a population with a more complex history [7]. It is therefore important to establish whether there are selective differences between classes (haplotypes) of mtDNA and Y chromosomes and, if so, whether these differences could have been sufficient to influence the distributions of haplotypes in existing populations. A precedent for this hypothesis has been established for mtDNA in that one mtDNA background increases susceptibility to Leber hereditary optic neuropathy [8]. Although studies of nucleotide diversity in global samples of Y chromosomes have suggested an absence of recent selective sweeps or bottlenecks [9], selection may, in principle, be very important for the Y chromosome because it carries several loci affecting male fertility [10] [11] and as many as 5% of males are infertile [11] [12]. Here, we show that one class of infertile males, PRKX/PRKY translocation XX males, arises predominantly on a particular Y haplotypic background. Selection is, therefore, acting on Y haplotype distributions in the population.