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AIR:EAU+RCI:VME; The present study focuses on the heterogeneous reaction between gaseous atomic chlorine and solid palmitic acid films, used as a proxy of the fatty acids detected in atmospheric airborne particles. This reaction is investigated in a coated wall flow tube reactor coupled to a molecular beam mass spectrometer. The reactive surfaces were prepared by coating the inner surface of the reactor. The initial ClE (TM) and Cl-2 uptake coefficient measured for these heterogeneous reactions is found to be fast: gamma(o) (Cl) = 0.07. The rapid formation of hydrogen chloride corresponding with the disappearance of atomic chlorine is highlighted. Furthermore, the formation of new chlorinated species on the solid substrate has been detected by TOF SIMS analysis leading to an ageing process of the surface. A heterogeneous recombination of Cl atoms to Cl-2 molecules was observed for aged surfaces.

Despite its potential reactivity due to ring strain, ethylene oxide (c-C2H4O) is a complex molecule that seems to be stable under the physical conditions of an interstellar dense core; indeed it has been detected towards several high-mass star forming regions with a column density of the order of 10e13cm-2 (Ikeda et al. 2001). To date, its observational abundances cannot be reproduced by chemical models and this may be due to the significant contribution played by its chemistry on grain surfaces. Recently, Ward and Price (2011) have performed experiments in order to investigate the surface formation of ethylene oxide starting with oxygen atoms and ethylene ice as reactants. We present a chemical model which includes the most recent experimental results from Ward and Price (2011) on the formation of c-C2H4O. We study the influence of the physical parameters of dense cores on the abundances of c-C2H4O. We verify that ethylene oxide can indeed be formed during the cold phase (when the ISM dense cores are formed), via addition of an oxygen atom across the C=C double bond of the ethylene molecule, and released by thermal desorption during the hot core phase. A qualitative comparison between our theoretical results and those from the observations shows that we are able to reproduce the abundances of ethylene oxide towards high-mass star-forming regions.

The heterogeneous thermal reaction between carbon disulphide (CS2) and oxygen (O) atoms, producing carbonyl sulphide (OCS), has been investigated under astrophysically relevant conditions in laboratory experiments. We study this reaction at a range of fixed surface temperatures between 15 and 70 K. Following the interaction of the reactants, on a highly oriented pyrolytic graphite surface at a particular surface temperature, we use temperature-programmed desorption coupled with time-of-flight mass spectrometry to determine the yield of OCS. Consequently, our experimental data reveal the temperature dependence of the OCS yield over the aforementioned range of surface temperatures. Our experimental results indicate that thermal O atoms can readily convert CS2 contained in the icy mantles on interstellar grains to OCS, without the need for energetic processing of the ice. Our data set shows that this reaction proceeds at surface temperatures as low as 15 K. Therefore, contrary to previous suggestions, CS2 molecules in icy mantles are perhaps unlikely to account for a substantial proportion of the sulphur content of dense interstellar clouds. Reaction barriers and Arrhenius pre-exponential factors, and hence rate constants, are derived for this surface reaction by fitting our experimental data using a kinetic model. Additionally, this modelling procedure yields values for the desorption energies of O atoms and OCS.

Calmodulin-dependent protein kinase III (CaM kinase III, elongation factor-2 kinase) is a unique member of the Ca2+/CaM-dependent protein kinase family. Activation of CaM kinase III leads to the selective phosphorylation of elongation factor 2 (eEF-2) and transient inhibition of protein synthesis. Recent cloning and sequencing of CaM kinase III revealed that this enzyme represents a new superfamily of protein kinases. The activity of CaM kinase III is selectively activated in proliferating cells; inhibition of the kinase blocked cells in G0/G1-S and decreased viability. To determine the significance of CaM kinase III in breast cancer, we measured the activity of the kinase in human breast cancer cell lines as well as in fresh surgical specimens. The specific activity of CaM kinase III in human breast cancer cell lines was equal to or greater than that seen in a variety of cell lines with similar rates of proliferation. The specific activity of CaM kinase III was markedly increased in human breast tumour specimens compared with that of normal adjacent breast tissue. The activity of this enzyme was regulated by breast cancer mitogens. In serum-deprived MDA-MB-231 cells, the combination of insulin-like growth factor I (IGF-I) and epidermal growth factor (EGF) stimulated cell proliferation and activated CaM kinase III to activities observed in the presence of 10% serum. Inhibition of enzyme activity blocked cell proliferation induced by growth factors. In MCF-7 cells separated by fluorescence-activated cell sorting, CaM kinase III was increased in S-phase over that of other phases of the cell cycle. In summary, the activity of Ca2+/CaM-dependent protein kinase III is controlled by breast cancer mitogens and appears to be constitutively activated in human breast cancer. These results suggest that CaM kinase III may contribute an important link between growth factor/receptor interactions, protein synthesis and the induction of cellular proliferation in human breast cancer. © 1999 Cancer Research Campaign

[Abridged] Ethylene oxide and its isomer acetaldehyde are important complex organic molecules because of their potential role in the formation of amino acids. Despite the fact that acetaldehyde is ubiquitous in the interstellar medium, ethylene oxide has not yet been detected in cold sources. We aim to understand the chemistry of the formation and loss of ethylene oxide in hot and cold interstellar objects (i) by including in a revised gas-grain network some recent experimental results on grain surfaces and (ii) by comparison with the chemical behaviour of its isomer, acetaldehyde. We test the code for the case of a hot core. The model allows us to predict the gaseous and solid ethylene oxide abundances during a cooling-down phase prior to star formation and during the subsequent warm-up phase. We can therefore predict at what temperatures ethylene oxide forms on grain surfaces and at what temperature it starts to desorb into the gas phase. The model reproduces the observed gaseous abundances of ethylene oxide and acetaldehyde towards high-mass star-forming regions. In addition, our results show that ethylene oxide may be present in outer and cooler regions of hot cores where its isomer has already been detected. Despite their different chemical structures, the chemistry of ethylene oxide is coupled to that of acetaldehyde, suggesting that acetaldehyde may be used as a tracer for ethylene oxide towards cold cores., Comment: 11 pages, 5 figures. Accepted by A&A

A growing number of students are completing undergraduate degrees in statistics and entering the workforce as data analysts. In these positions, they are expected to understand how to utilize databases and other data warehouses, scrape data from Internet sources, program solutions to complex problems in multiple languages, and think algorithmically as well as statistically. These data science topics have not traditionally been a major component of undergraduate programs in statistics. Consequently, a curricular shift is needed to address additional learning outcomes. The goal of this paper is to motivate the importance of data science proficiency and to provide examples and resources for instructors to implement data science in their own statistics curricula. We provide case studies from seven institutions. These varied approaches to teaching data science demonstrate curricular innovations to address new needs. Also included here are examples of assignments designed for courses that foster engagement of undergraduates with data and data science.

The 11-zinc finger protein CCTC-binding factor (CTCF) employs different sets of zinc fingers to form distinct complexes with varying CTCF- target sequences (CTSs) that mediate the repression or activation of gene expression and the creation of hormone-responsive gene silencers and of diverse vertebrate enhancer-blocking elements (chromatin insulators). To determine how these varying effects would integrate in vivo, we engineered a variety of expression systems to study effects of CTCF on cell growth. Here we show that ectopic expression of CTCF in many cell types inhibits cell clonogenicity by causing profound growth retardation without apoptosis. In asynchronous cultures, the cell-cycle profile of CTCF-expressing cells remained unaltered, which suggested that progression through the cycle was slowed at multiple points. Although conditionally induced CTCF caused the S-phase block, CTCF can also arrest cell division. Viable CTCF-expressing cells could be maintained without dividing for several days. While MYC is the well-characterized CTCF target, the inhibitory effects of CTCF on cell growth could not be ascribed solely to repression of MYC, suggesting that additional CTS-driven genes involved in growth-regulatory circuits, such as p19ARF, are likely to contribute to CTCF-induced growth arrest. These findings indicate that CTCF may regulate cell-cycle progression at multiple steps within the cycle, and add to the growing evidence for the function of CTCF as a tumor suppressor gene.

The nucleoprotein (NP) of Newcastle disease virus (NDV) was selected to study the relative importance of an internal structural protein in the avian immune response. The NP gene of the virulent, neurotropic NDV Texas GB (TGB) strain was cloned and sequenced. Nucleotide sequence data for the NP gene allowed comparison of the deduced amino acid sequences for the NP genes of NDV-TGB and the avirulent duck isolate NDV-D26. These comparisons demonstrated an 89% nucleotide sequence homology and a 97% homology between the deduced amino acid sequences. The NDV-TGB NP expressed in recombinant vaccinia virus (rVAC) was electrophoretically and immunologically identical to the wild-type NDV-TGB. Although inoculation of chickens with the recombinant vaccinia virus expressing the NDV NP gene elicited anti-NDV antibodies in higher titers than in birds inoculated with live LaSota NDV, this strong anti-NDV response did not protect against lethal challenge with NDV-TGB.

Calmodulin-dependent protein kinases phosphorylate certain substrates that have been implicated in regulating cellular proliferation. For example, upon mitogenic stimulation, there is a rapid activation of calmodulin-dependent protein kinase III (CaM kinase III), which leads to the phosphorylation of elongation factor 2. Recently, our laboratory demonstrated that the activity of CaM kinase III is increased in glioma cells following exposure to mitogens and is diminished or absent in nonproliferating glial tissue. Rottlerin, a 5,7-dihydroxy-2,2-dimethyl-6-(2,4,6-trihydroxy-3-methyl-5-acetylbenzy l)-8-cinnamoyl-1,2-chromene isolated from the pericarps of Mallotus phillippinensis, has been shown to be an effective CaM kinase III inhibitor. Therefore, we evaluated the effects of rottlerin on the growth and viability of glioblastoma cell lines. Rottlerin decreased growth and induced cytotoxicity in rat (C6) and two human gliomas (T98G and U138MG) at concentrations that inhibited the activity of CaM kinase III in vitro and in vivo. Far less demonstrable effects were observed on other Ca2++/CaM-sensitive kinases. Incubation of glial cells with rottlerin produced a block at the G1-S interface and the appearance of a population of cells with a2N complement of DNA. In addition, rottlerin induced changes in cellular morphology such as cell shrinkage, accumulation of cytoplasmic vacuoles, and packaging of cellular components within membranes. These data suggest that CaM kinase III may be an important link between the activation of CaM-dependent signaling, proliferation, and viability in malignant cells, and that inhibition of CaM kinase III may represent an interesting pharmacological target in malignant gliomas.

This article reports the results of a survey conducted to determine the relationship between Machiavellianism and job satisfaction among radiographers. As predicted by the literature, the survey showed a negative correlation between these two constructs-radiographers with higher Machiavellianism had lower job satisfaction, while those with the lowest Machiavellianism had the highest job satisfaction. Education, gender, marital status, race, position and time in position had no significant effect on the two constructs.

Time-of-flight mass spectrometry and two-dimensional coincidence techniques have been used to determine, for the first time, the relative precursor-specific partial ionization cross sections following electron-methane collisions. Precursor-specific partial ionization cross sections quantify the contribution of single, double, and higher levels of ionization to the partial ionization cross section for forming a specific ion (e.g. CH(+)) following electron ionization of methane. Cross sections are presented for the formation of H(+), H(2)(+), C(+), CH(+), CH(2)(+), and CH(3)(+), relative to CH(4)(+), at ionizing electron energies from 30 to 200 eV. We can also reduce our dataset to derive the relative partial ionization cross sections for the electron ionization of methane, for comparison with earlier measurements. These relative partial ionization cross sections are in good agreement with recent determinations. However, we find that there is significant disagreement between our partial ionization cross sections and those derived from earlier studies. Inspection of the values of our precursor-specific partial ionization cross sections shows that this disagreement is due to the inefficient collection of energetic fragment ions in the earlier work. Our coincidence experiments also show that the lower energy electronic states of CH(4)(2+) populated by electron double ionization of CH(4) at 55 eV are the same (ground (3)T(1), first excited (1)E(1)) as those populated by 40.8 eV photoionization. The (3)T(1) state dissociating to form CH(3)(+) + H(+) and CH(2)(+) + H(2)(+) and the (1)E(1) to form CH(2)(+) + H(+) and CH(+) + H(+). At this electron energy, we also observe population of the first excited triplet state of CH(4)(2+) ((3)T(2)) which dissociates to both CH(2)(+) + H(+) + H and CH(+) + H(+) + H(2).

A recombinant mouse cDNA fragment encoding the G domain of the basement membrane laminin A chain was inserted into the eukaryotic baculovirus expression vector pVL1392 modified to produce fusion proteins carrying the rat fibronectin signal. G domain, expressed and secreted as a soluble glycoprotein (rG), was purified to near homogeneity without denaturing conditions. By electron microscopy rG possessed the same globular morphology as found in laminin. rG was cleaved with elastase into two fragments, rG70 and rG50. The latter fragment possessed the identical N terminus as laminin fragment E3 and both shared the same secondary structure by circular dichroism. rG, and rG containing a deletion (residues 2980-3028) rich in basic residues bound to heparin with similar avidity. rG also promoted mouse C2 myoblast cell adhesion and spreading, and evaluation of myoblasts on rG70 and rG50 further revealed that cell spreading was an activity confined to the more proximal sequence of rG70. Antibody specific for rG70 completely blocked cell adhesion to intact laminin in contrast to antibody specific for E3. Finally rG did not inhibit laminin polymerization. These data support the role of G domain in cell and heparin binding, but not laminin self-assembly, and the approach provides a means to further characterize these functions.

This report documents the results of an independent stability and control analysis of the control systems and procedures of the navigation development satellite (NDS) for the global positioning system (GPS). The analysis consisted of detailed analytical investigation substantiated with sophisticated satellite system modeling and simulation of the following GPS mission events: Spin phase, Despin, Earth acquisition, Panel deployment, Sun acquisition, and On-orbit operations. The results of the analysis indicated satisfactory performance in all mission phases analyzed. A redesign of the jet control system was recommended to facilitate earth acquisition operations. (Author)