bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of Nickel in Food Samples by Flame Atomic Absorption Spectroscopy after Preconcentration and Microextraction Based Ionic Liquids Using Full Factorial and Central Composite Design
Authors: Zarei Zohre , Shemirani Farzaneh
Published: August 2012

Abstract:  In this research, a microextraction technique based on ionic liquids (ILs) termed in situ solvent formation microextraction (ISFME) was used for determination of nickel in solutions. 1‐(2‐pyridylazo)‐2‐naphtol (PAN) was chosen as a complexing agent. After preconcentration, the settled IL‐phase was dissolved in 50 μL of ethanol and aspirated into the flame atomic absorption spectrometer (FAAS) using a home‐made microsample introduction system. Injection of 50 μL volumes of analyte into an air–acetylene flame provided very sensitive spike‐like and reproducible signals.

ISFME is based on phase separation phenomenon of ionic liquids in aqueous solutions. This method is simple and rapid for extraction and preconcentration of metal ions from food samples and can be applied for the sample solutions containing very high concentrations of salt. Furthermore, this technique is much safer in comparison with the organic solvent extraction because of using ionic liquid.

The effective parameters such as amount of IL, salt effect, concentration of the chelating agent and ion pairing agent were inspected by a full factorial design to identify important parameters and their interactions. Next, a central composite design was applied to obtain optimum point of the important parameters. Under the optimum conditions, the calibration graph was linear over the range of 2 to 80 ng/mL. The limit of detection and relative standard deviation (n= 6) were 0.6 ng/mL and 2%, respectively.
Private Information and the Exercise of Executive Stock Options
Authors: Brooks Robert , Chance Don M. , Cline Brandon
Published: August 2012

This paper finds strong evidence that executives use private information when exercising their stock options. The most informed executives tend to exercise early, do not exercise on the vest date, do not exercise to capture dividends, exercise a high percentage of their options, and exercise when the option is the least in‐the‐money. We also find that exercises around resignation and retirement are followed by significant negative abnormal returns. Furthermore, the operating performance of firms following exercises motivated by private information is significantly worse than that of firms in which the exercises are not motivated by private information.
Profiling the careers of Thoroughbred horses racing in Australia between 2000 and 2010
Authors: VELIE B. D. , WADE C. M. , HAMILTON N. A.
Published: August 2012

Reasons for performing study: Research investigating trends in racehorse careers require a benchmark for accurate comparison. Currently little whole population data exists for horses racing in Australia.

Objectives: To determine the range and variation in career length and number of career starts for horses racing in Australia. To document and provide evidence regarding the current differences between the sexes for career length and careers starts.

Methods: Racing data were collected for Thoroughbreds over a 10‐year period. Career length, number of career starts and spells per year were evaluated. Statistical analyses were performed using the statistical package R.

Results: A total of 2,782,774 performance records yielded career information for 164,046 horses. Median career length and number of career starts for the population were 14.7 months and 10 starts, respectively. Significant differences (P<0.001) were present between the sexes for all career outcomes. Between 2000 and 2010, the percentage of Thoroughbreds racing in Australia with careers longer than 12, 24, 36 and 48 months was 56.65, 32.35, 16.66 and 7.74, respectively.

Conclusions and potential relevance: Clear differences in career outcomes exist between intact males, females and geldings racing in Australia. Future research should be conscious of these differences when analysing population data.
Monte Carlo study of in‐field and out‐of‐field dose distributions from a linear accelerator operating with and without a flattening‐filter
Authors: Almberg S. S. , Frengen J. , Lindmo T.
Published: August 2012

Purpose:

To compare dosimetric characteristics of 6 MV photon fields originating from a linear accelerator operating with (FF) and without (FFF) a flattening‐filter. The main objective is to establish a FFF model that results in similar depth‐dose and build‐up profiles as the original FF model, and subsequently estimate and compare out‐of‐field dose distributions.

Methods:

The EGSnrc Monte Carlo user codes BEAMnrc and DOSXYZnrc are used for photon beam simulations of an Elekta linear accelerator and dose calculations in a water phantom, respectively. Three beam models were analyzed: (1) the conventional linear accelerator with the flattening‐filter in place and incident electron energy 6.45 MeV (FF 6.45 MeV), (2) similar flattening‐filter‐free model (FFF 6.45 MeV), and (3) as (2) but with increased electron energy (FFF 8.0 MeV). The field size 5 × 5 cm2 was used for characterization of dose output, depth dose profiles, and photon spectrum. The field size 40 × 40 cm2 was used for characterization of cross‐field photon energy, photon fluence, and dose distributions. Out‐of‐field dose distributions were analyzed in both in‐plane and cross‐plane directions for 5 × 5 cm2 and 10 × 10 cm2 fields.

Results:

Comparable depth dose distributions, including the build‐up region, for FF and FFF fields were achieved by increasing the electron energy from 6.45 MeV to 8.0 MeV for the FFF beam. The FFF beams result in reduced out‐of‐field dose compared to the FF beam: the reduction was most apparent in the cross‐plane direction and more pronounced by the FFF 8.0 MeV beam compared to the FFF 6.45 MeV beam. Differences in out‐of‐field dose due to direction (in‐plane vs cross‐plane) were up to 40% for the FF beam; this effect was significantly reduced for the FFF beams. As the flattening‐filter is a major source of contaminating electrons, superficial out‐of‐field dose was expected, and was found to be, reduced for FFF beams.

Conclusions:

The build‐up and depth‐dose characteristics of a conventional “6 MV” beam can be maintained when changing to a flattening‐filter‐free modality by increasing the incident electron energy from 6.45 MeV to 8.0 MeV. This will at the same time reduce the out‐of‐field dose for regions up to 20 cm from the central axis by 10%–30% compared to the original FF situation.
Zinc Competition among the Intestinal Microbiota
Authors: Gielda Lindsay M. , DiRita Victor J.
Published: August 2012

Bioavailable levels of trace metals, such as iron and zinc, for bacterial growth in nature are sufficiently low that most microbes have evolved high-affinity binding and transport systems. The microbe
Campylobacter jejuni
lives in the gastrointestinal tract of chickens, the principal source of human infection. A high-affinity ABC transporter for zinc uptake is required for
Campylobacter
survival in chicken intestines in the presence of a normal microbiota but not when chickens are raised with a limited microbiota. Mass spectrometric analysis of cecal contents revealed the presence of numerous zinc-binding proteins in conventional chicks compared to the number in limited-microbiota chicks. The presence of a microbiota results in the production of host zinc-binding enzymes, causing a growth restriction for bacteria that lack the high-affinity zinc transporter. Such transporters in a wide range of pathogenic bacteria make them good targets for the development of broad-spectrum antimicrobials.

IMPORTANCE
Zinc is an essential trace element for the growth of most organisms. Quantities of zinc inside cells are highly regulated, as too little zinc does not support growth, while too much zinc is toxic. Numerous bacterial cells require zinc uptake systems for growth and virulence. The work presented here demonstrates that the microbiota in the gastrointestinal tract reduces the quantity of zinc. Without a high-affinity zinc transporter,
Campylobacter jejuni
, a commensal organism of chickens, is unable to replicate or colonize the gastrointestinal tract. This is the first demonstration of zinc competition between microbiota in the gastrointestinal tract of a host. These results could have profound implications in the field of microbial pathogenesis and in our understanding of host metabolism and the microbiota.
MreA Functions in the Global Regulation of Methanogenic Pathways in Methanosarcina acetivorans
Authors: Reichlen Matthew J. , Vepachedu Venkata R. , Murakami Katsuhiko S. , Ferry James G.
Published: August 2012

Results are presented supporting a regulatory role for the product of the MA3302 gene locus (designated MreA) previously annotated as a hypothetical protein in the methanogenic species
Methanosarcina acetivorans
of the domain
Archaea
. Sequence analysis of MreA revealed identity to the TrmB family of transcription factors, albeit the sequence is lacking the sensor domain analogous to TrmBL2, abundant in nonmethanogenic species of the domain
Archaea
. Transcription of
mreA
was highly upregulated during growth on acetate versus methylotrophic substrates, and an
mreA
deletion (Δ
mreA
) strain was impaired for growth with acetate in contrast to normal growth with methylotrophic substrates. Transcriptional profiling of acetate-grown cells identified 280 genes with altered expression in the Δ
mreA
strain versus the wild-type strain. Expression of genes unique to the acetate pathway decreased whereas expression of genes unique to methylotrophic metabolism increased in the Δ
mreA
strain relative to the wild type, results indicative of a dual role for MreA in either the direct or indirect activation of acetate-specific genes and repression of methylotrophic-specific genes. Gel shift experiments revealed specific binding of MreA to promoter regions of regulated genes. Homologs of MreA were identified in
M. acetivorans
and other
Methanosarcina
species for which expression patterns indicate roles in regulating methylotrophic pathways.

IMPORTANCE
Species in the domain
Archaea
utilize basal transcription machinery resembling that of the domain
Eukarya
, raising questions addressing the role of numerous putative transcription factors identified in sequenced archaeal genomes. Species in the genus
Methanosarcina
are ideally suited for investigating principles of archaeal transcription through analysis of the capacity to utilize a diversity of substrates for growth and methanogenesis.
Methanosarcina
species switch pathways in response to the most energetically favorable substrate, metabolizing methylotrophic substrates in preference to acetate marked by substantial regulation of gene expression. Although conversion of the methyl group of acetate accounts for most of the methane produced in Earth’s biosphere, no proteins involved in the regulation of genes in the acetate pathway have been reported. The results presented here establish that MreA participates in the global regulation of diverse methanogenic pathways in the genus
Methanosarcina
. Finally, the results contribute to a broader understanding of transcriptional regulation in the domain
Archaea
.
Low Levels of β-Lactam Antibiotics Induce Extracellular DNA Release and Biofilm Formation in Staphylococcus aureus
Authors: Kaplan Jeffrey B. , Izano Era A. , Gopal Prerna , Karwacki Michael T. , Kim Sangho , Bose Jeffrey L. , Bayles Kenneth W. , Horswill Alexander R.
Published: August 2012

Subminimal inhibitory concentrations of antibiotics have been shown to induce bacterial biofilm formation. Few studies have investigated antibiotic-induced biofilm formation in
Staphylococcus aureus
, an important human pathogen. Our goal was to measure
S. aureus
biofilm formation in the presence of low levels of β-lactam antibiotics. Fifteen phylogenetically diverse methicillin-resistant
Staphylococcus aureus
(MRSA) and methicillin-sensitive
S. aureus
(MSSA) strains were employed. Methicillin, ampicillin, amoxicillin, and cloxacillin were added to cultures at concentrations ranging from 0× to 1× MIC. Biofilm formation was measured in 96-well microtiter plates using a crystal violet binding assay. Autoaggregation was measured using a visual test tube settling assay. Extracellular DNA was quantitated using agarose gel electrophoresis. All four antibiotics induced biofilm formation in some strains. The amount of biofilm induction was as high as 10-fold and was inversely proportional to the amount of biofilm produced by the strain in the absence of antibiotics. MRSA strains of lineages USA300, USA400, and USA500 exhibited the highest levels of methicillin-induced biofilm induction. Biofilm formation induced by low-level methicillin was inhibited by DNase. Low-level methicillin also induced DNase-sensitive autoaggregation and extracellular DNA release. The biofilm induction phenotype was absent in a strain deficient in autolysin (
atl
). Our findings demonstrate that subminimal inhibitory concentrations of β-lactam antibiotics significantly induce autolysin-dependent extracellular DNA release and biofilm formation in some strains of
S. aureus
.

IMPORTANCE
The widespread use of antibiotics as growth promoters in agriculture may expose bacteria to low levels of the drugs. The aim of this study was to investigate the effects of low levels of antibiotics on bacterial autoaggregation and biofilm formation, two processes that have been shown to foster genetic exchange and antibiotic resistance. We found that low levels of β-lactam antibiotics, a class commonly used in both clinical and agricultural settings, caused significant autoaggregation and biofilm formation by the important human pathogen
Staphylococcus aureus
. Both processes were dependent on cell lysis and release of DNA into the environment. The effect was most pronounced among multidrug-resistant strains known as methicillin-resistant
S. aureus
(MRSA). These results may shed light on the recalcitrance of some bacterial infections to antibiotic treatment in clinical settings and the evolution of antibiotic-resistant bacteria in agricultural settings.
Influenza Virus Resistance to Human Neutralizing Antibodies
Authors: Crowe James E.
Published: August 2012

The human antibody repertoire has an exceptionally large capacity to recognize new or changing antigens through combinatorial and junctional diversity established at the time of V(D)J recombination and through somatic hypermutation. Influenza viruses exhibit a relentless capacity to escape the human antibody response by altering the amino acids of their surface proteins in hypervariable domains that exhibit a high level of structural plasticity. Both parties in this high-stakes game of shape shifting drive structural evolution of their functional proteins (the B cell receptor/antibody on one side and the viral hemagglutinin and neuraminidase proteins on the other) using error-prone polymerase systems. It is likely that most of the genetic mutations that occur in these systems are deleterious, resulting in the failure of the B cell or virus with mutations to propagate in the immune repertoire or viral quasispecies. A subset of mutations is tolerated in functional surface proteins that enter the B cell or virus progeny pool. In both cases, selection occurs in the population of mutated and unmutated species. In cases where the functional avidity of the B cell receptor is increased significantly, that clone may be selected for preferential expansion. In contrast, an influenza virus that “escapes” the inhibitory effect of secreted antibodies may represent a high proportion of the progeny virus in that host. The recent paper by O’Donnell et al. [C. D. O’Donnell et al., mBio 3(3):e00120-12, 2012] identifies a mechanism for antibody resistance that does not require escape from binding but rather achieves a greater efficiency in replication.
Biodiversity or bioenergy: is deadwood conservation an environmental issue for French forest owners?1This article is one of a selection of papers from the International Symposium on Dynamics and Ecological Services of Deadwood in Forest Ecosystems.
Authors: Deuffic Philippe , Lyser Sandrine
Published: August 2012

Forest owners are confronted with contradictory views on the importance of deadwood. Environmentalists argue that it should be left in the forest to conserve biodiversity, provide a habitat for specific fauna and flora, and maintain soil quality through wood decay. Conversely, industrial stakeholders, and some public decision makers, advocate harvesting deadwood. Based on a sociological survey and qualitative interviews, we first analyzed the detailed environmental opinions and values of four groups of French foresters as well as their attitudes towards biodiversity, in particular regarding deadwood conservation. We identified various types of attitudes towards deadwood, which could be seen as waste, an unprofitable by-product, a meaningless entity, or a key part of the ecosystem. We then studied the arguments leading them to choose between deadwood conservation and deadwood harvesting for bioenergy production. On one hand, foresters are interested in short-term profitability and pest control, while others fear potential loss of fertility. Finally, the article shows that specific approaches to deadwood conservation ought to be negotiated at a local scale, pending further scientific investigation into the impact of deadwood on biodiversity and the development of more positive attitudes toward ecological concerns in the forest owners’ community.
Species, live status, and diameter are important tree features for diversity and abundance of tree microhabitats in subnatural montane beech–fir forests1This article is one of a selection of papers from the International Symposium on Dynamics and Ecological Services of Deadwood in Forest Ecosystems.
Authors: Larrieu Laurent , Cabanettes Alain
Published: August 2012

Because quantitative data on the distribution of whole microhabitat sets are still lacking to indirectly assess taxonomic biodiversity in forests, we studied the distribution of seven key microhabitat types in 10 montane European beech ( Fagus sylvatica L.) – silver fir ( Abies alba Mill.) forests (Pyrénées, France) that had not been harvested for several decades. We examined 2105 live trees and 526 snags. Frequencies of cavities and dendrothelms were significantly higher on live beech than on fir. Sap runs were strictly found on live fir. Frequencies of cracks and saproxylic fungi were significantly higher on snags than on live trees. Seventy percent of live beeches but only 18% of firs carried one or more microhabitats. For both beech and fir and for each microhabitat type, we found, using the recursive partitioning method, one to three diameter thresholds that each corresponded to a significant change in the probability of microhabitat presence. When considering the whole microhabitat set, the most significant diameter thresholds were 42, 60, 73, and 89 cm for beech and 99 cm for fir. We suggest that forest managers conserve (i) mixed stands and (ii) beech with a diameter at breast height >90 cm and fir >100 cm. These rules should be adapted for each forest ecosystem.
Phenology and duration of remigial moult in Surf Scoters (Melanitta perspicillata) and White-winged Scoters (Melanitta fusca) on the Pacific coast of North America
Authors: Dickson R.D. , Esler D. , Hupp J.W. , Anderson E.M. , Evenson J.R. , Barrett J.
Published: August 2012

By quantifying phenology and duration of remigial moult in Surf Scoters ( Melanitta perspicillata (L., 1758)) and White-winged Scoters ( Melanitta fusca (L., 1758)), we tested whether timing of moult is dictated by temporal optima or constraints. Scoters (n = 3481) were captured during moult in Alaska, British Columbia, and Washington, and remigial emergence dates were determined. We provide evidence for a pre-emergence interval of 7.3 days that occurs after old primaries are shed and before new ones become visible. All age and sex classes of both scoter species exhibited a wide range of emergence dates (Surf Scoters: 26 June to 22 September; White-winged Scoters: 6 July to 21 September) suggestive of a lack of strong temporal optima for remigial moult. For both species, timing of moult was influenced by site, year, age, and sex. Relative to other waterfowl species, scoters have typical remigial growth rates (Surf Scoters: 3.9 mm·day–1; White-winged Scoters: 4.3 mm·day–1) but a long flightless period (34–49 days), in part because their relatively high wing-loading requires a greater proportion of feather regrowth to regain flight. Our data suggest that moulting scoters are not under strong selective pressure to complete moult quickly.
Changes in expression of hepatic genes involved in lipid metabolism during prehibernation period in captive adult female Japanese black bears (Ursus thibetanus japonicus)
Authors: Shimozuru Michito , Akari Kamine , Tsubota Toshio
Published: August 2012

Body fat accumulation in the prehibernation period is crucial for survival and reproduction during hibernation for bears. Bear body mass increases rapidly during their autumnal hyperphagia phase, which is attributed not only to an increase in food availability, but also to physiological changes in lipid metabolism. To test this hypothesis, we investigated changes in blood biochemical values and mRNA expression levels of hepatic genes involved in lipid metabolism during the active period (June, August, October, and November) in Japanese black bears ( Ursus thibetanus japonicus Schlegel, 1857), which were fed a constant ration throughout this period. Blood biochemical analysis revealed that plasma triglyceride concentrations decreased in October and November, implying that peripheral triglyceride uptake was accelerated in autumn. The liver was sampled by needle biopsy. Real-time polymerase chain reaction (PCR) analysis revealed that mRNA expressions of enzymes involved in glycolysis (glucokinase), as well as fatty acid and triglyceride synthesis (ATP-citrate lyase, acetyl-CoA carboxykinase 1, fatty acid synthase, and diacylglycerol O-acyltransferase 2), increased in November, which suggests that hepatic lipogenesis becomes accelerated during the hyperphagia phase. These results suggest that lipid metabolism is seasonally controlled even without changes in food intake. These physiological changes seen in the prehibernation period would contribute to the rapid mass gain necessary for hibernation.
Sex and strain differences in isotope turnover rates and metabolism in house mice (Mus musculus)
Authors: MacAvoy S.E. , Lazaroff S. , Kraeer K. , Arneson L.S.
Published: August 2012

The rate of nutrient incorporation into most organisms is an unknown but important factor in temporally variable systems. We investigate within-species variation in tissue turnover and metabolic rate among house mice ( Mus musculus L., 1758). By establishing a predictive relationship between tissue turnover rate and metabolic rate, field-based studies could more easily estimate tissue turnover rates using metabolic rate as a surrogate. Here, a diet change was administered using male and female mice of two strains (BALB/c and CBA/J) to test whether a predictive relationship was detectable within a species. Resting metabolic rate (mean values of 1.50–3.64 mL O2·h–1·g–1) and metabolic tissue turnover m (0.02–0.07), were significantly different between sexes, but not between strains. Females of both strains exhibited a nitrogen turnover rate significantly faster than males. Females had less mass than males, which could account for the differences in tissue replacement rates between sexes. The difference in metabolic rate within a species (between strains) may not be large enough to affect the rate of tissue turnover, suggesting that field researchers may be able to assume similar turnover rates among same-sex individuals of the same species. However, it may be important to account for sexual dimorphism when studying tissue turnover and metabolism.
Gastrointestinal parasites of coyotes (Canis latrans) in the metropolitan area of Calgary, Alberta, Canada
Authors: Liccioli S. , Catalano S. , Kutz S.J. , Lejeune M. , Verocai G.G. , Duignan P.J. , Fuentealba C. , Hart M. , Ruckstuhl K.E. , Massolo A.
Published: August 2012

Disease ecology is a relevant but relatively unexplored subject of research in urban coyotes ( Canis latrans Say, 1823). In fact, this carnivore may play a role in the circulation of parasites that can have implications on the health of humans and domestic dogs, but can also be affected by pathogens transmitted from domestic reservoirs. To investigate the gastrointestinal parasites of urban coyotes in Calgary, Alberta, Canada, we analyzed 61 carcasses and 247 fecal samples collected within the metropolitan area, including city parks, in 2009–2010. We found nine parasite taxa: Toxascaris leonina (Linstow, 1902), Uncinaria stenocephala (Railliet, 1884), Ancylostoma caninum (Ercolani, 1859), Pterygodermatites affinis (Jägerskiöld, 1904), Trichuris vulpis (Froelich, 1789), Echinococcus multilocularis Leuckart, 1863, Taenia crassiceps (Zeder, 1800), genus Giardia Kunstler, 1882, and genus Cystoisospora Frenkel, 1977. Factors related to coyote ecology, habitat characteristics, and dog management likely influence the community of coyote parasites in an urban environment, and need to be taken into account to assess the actual role of this carnivore in the maintenance of parasites in the city landscape. Further research is needed to assess the current risk for transmission of potentially zoonotic parasites (e.g., E. multilocularis, T. crassiceps, Giardia sp.) among coyotes, dogs, and humans.
Two social communities in the Pearl River Estuary population of Indo-Pacific humpback dolphins (Sousa chinensis)
Authors: Dungan S.Z. , Hung S.K. , Wang J.Y. , White B.N.
Published: August 2012

The way human activities impact animal populations can depend on social structure, which is important to understand in social species such as cetaceans. We investigated association patterns in Indo-Pacific humpback dolphins ( Sousa chinensis (Osbeck, 1765)) inhabiting the Pearl River Estuary near Lantau Island, Hong Kong, using a 10-year data set for 88 individuals. Our analyses revealed two social communities. Each had its own region of core use, to the north and to the west of the island, but their overall ranges partially overlapped northwest of Lantau. The northern community had a fission–fusion structure characterized by short-term associations, while the western community had more long-term associations. Mixed-community groups included calves more often than exclusive groups, so between-community associations may arise from common habitat usage, by females especially, in the overlap area. Recent range extensions by the northern community into the west are likely a response to habitat destruction north of Lantau. This suggests ease of movement between the north and the west is necessary for northern-community dolphins to access suitable habitat, and gives new concern to construction projects planned for the region. We emphasize our study as an example of how sociobiological information can be important in understanding human impacts on animal populations.
ASYMPTOTIC ENTANGLEMENT IN 1D QUANTUM WALKS WITH A TIME-DEPENDENT COINED
Authors: SALIMI S. , YOSEFJANI R.
Published: August 2012

Discrete-time quantum walk evolve by a unitary operator which involves two operators a conditional shift in position space and a coin operator. This operator entangles the coin and position degrees of freedom of the walker. In this paper, we investigate the asymptotic behavior of the coin position entanglement (CPE) for an inhomogeneous quantum walk which determined by two orthogonal matrices in one-dimensional lattice. Free parameters of coin operator together provide many conditions under which a measurement perform on the coin state yield the value of entanglement on the resulting position quantum state. We study the problem analytically for all values that two free parameters of coin operator can take and the conditions under which entanglement becomes maximal are sought.
THE EFFECT OF PHOSPHORUS AND COPPER OXIDE ON THE PHOTOLUMINESCENCE CHARACTERISTICS OF Li2 CO3–K2CO3–H3BO3 GLASS
Authors: ALAJERAMI YASSER SALEH MUSTAFA , HASHIM SUHAIRUL , HASSAN WAN MUHAMAD SARIDAN WAN , RAMLI AHMAD TERMIZI , KASIM AZMAN
Published: August 2012

In this paper, glass sample was prepared by the conventional wet chemical method. A series of borate glass consists of lithium and potassium carbonate doped with 0.1mol% of NH 4 H 2 PO 4 and copper oxides have been well prepared. The structural and the optical properties of the glass have been measured by means of their XRD, FTIR, PL and UV-VIS spectra. From the results, the current sample shows a nonlinear optical property by emitting two prominent peaks at 504 and 540 nm (green light emission) under the excitation of 630 nm. A significant enhancement on the PL spectra due to increment of phosphorus impurities dopant has also been observed. Some other physical parameters were also been measured and identified. The results of structural as well as the optical were then being estimated and discussed.
Synthesis, RNA binding and nuclease activity of porphyrin-hydroxamic acid derivatives
Authors: Marketaki Maria , Touloupakis Eleftherios , Charalambidis Georgios , Chalbot Marie-Cécile , Ghanotakis Demetrios F. , Coutsolelos Athanassios G.
Published: August 2012

The interaction modes and nuclease activity against RNA of methylpyridiniumyl/phenyl-hydroxamic acid porphyrin adducts have been investigated. These compounds are derived from the tetracationic meso-tetrakis(N-methyl-4-pyridiniumyl)porphyrin (H2TMPyP-4) by replacing one or two pyridinium rings with a phenyl group. This group is bearing an aliphatic chain of three carbon atoms in the para position to a hydroxamic acid. A different interaction mode is observed depending on the number of charges and hydroxamic acid function. The nuclease activity of the porphyrin adducts against RNA has been demonstrated. Also the effect of the presence of various lanthanide ions on the porphyrin nuclease activity has been tested.
Design of guanidinium porphyrins as potential G-quadruplex ligands
Authors: Xu Hai-Jun , Richard Philippe , Barbe Jean-Michel , Gros Claude P.
Published: August 2012

We report herein an easy and smooth synthesis of two novel tetra-meso-substituted porphyrins bearing terminal guanidinium functionalities. These two guanidine derivatives are the porphyrin-based analogs of ZnPC , a closely related phthalocyanine-based molecule with four guanidinium arms already reported as an efficient G-quadruplex ligand.
Discotic liquid crystals of transition metal complexes 45: parity effect of the number of d-electrons on stacking distances in the columnar mesophases of octakis-(m-alkoxyphenoxy)phthalocyaninato metal(II) complexes
Authors: Sato Hiroyuki , Igarashi Kensaku , Yama Yoshitaka , Ichihara Masahiro , Itoh Eiji , Ohta Kazuchika
Published: August 2012

We have synthesized 34 novel homologous discotic liquid crystals, octakis(m-alkoxyphenoxy)phthalocyaninato metal(II) {abbreviated as (m- CnOPhO)8PcM (M = Co(1), Ni(2), Cu(3), Zn(4) and H2 (5); n = 8(a), 10(b), 12(c), 14(d), 16(e), 18(f) and 20(g))}, and investigated parity effect of the number of d-electrons on the stacking distances in their columnar mesophases. It was revealed from temperature-dependent wide angle X-ray diffraction studies that each of the cobalt(II) (d7) complexes (1a–1g) and the copper(II) (d9) complexes (3b–3g) showed a single hexagonal ordered columnar (Colho) mesophase with a very short stacking distance at 3.3 Å, and that the nickel(II) (d8) complexes (2a–2g) and the metal-free (d0) derivatives (5a–5g) showed a single pseudo-hexagonal ordered columnar (Colrho) mesophase with a little bit longer stacking distances at 3.4 Å. Very interestingly, the nickel complex (2a) and metal-free derivatives (5a–5c) gave an extremely big (001) reflection peak with the second (002) reflection peak. Furthermore, the zinc(II) (d10) complexes (4a–4g) showed two different rectangular ordered columnar mesophases, Colro(P2/m) and Colro(P21/a), with a little bit longer stacking distance at 3.4 Å. Thus, the shorter stacking distance, 3.3 Å, appeared for the odd number of d-electrons, whereas the longer stacking distance, 3.4 Å, appeared for the even number of d-electrons. Hence, the stacking distances depend on parity of the number of d-electrons in the central metal(II). To our best knowledge, it is the first example of parity effect on the stacking distances in columnar mesophases.
Postscheduling buffer management trade-offs in streaming software synthesis
Authors: Foroozannejad Mohammad H. , Hodges Trevor , Hashemi Matin , Ghiasi Soheil
Published: August 2012

Streaming applications, which are abundant in many disciplines such as multimedia, networking, and signal processing, require efficient processing of a seemingly infinite sequence of input data. In the context of streaming software synthesis from data flow graphs, we study the inherent trade-off between memory requirement and compilation runtime, under a given task firing schedule. We utilize postscheduling analysis granularity to control the amount of details in characterization of buffer's spatio-temporal footprints. Subsequently, we transform the buffer allocation problem to two-dimensional packing of polygons, where complexity of the packing problem (e.g., polygon shapes) is determined by the analysis granularity. We develop an evolutionary packing optimization algorithm which readily yields buffer allocations. Experimental results highlight the trade-off between complexity of the analysis and the total buffer size of generated implementations. In addition, they show dramatic improvements in total buffer size, if one is willing to pay the additional cost in optimization runtime.
Model querying with graphical notation of QVT relations
Authors: Li Dan , Li Xiaoshan , Stolz Volker
Published: August 2012

As a standard high-level model transformation language, QVT Relations defines a graphical notation, which provides a concise, intuitive way to specify transformations. However, QVT Relations relies only on the textual language OCL for model querying, leading to verbose and complicated OCL expressions. Here, we present a graphical model query facility based on the checking semantics and pattern matching of QVT Relations. The query facility also borrows from QVT Relations the graphical notation. In addition we propose an approach to map the queries into XSLT to facilitate their execution. We have developed a tool for designing the queries and automatically generating the XSLT programs.
Corrective Enforcement
Authors: Khoury Raphaël , Tawbi Nadia
Published: August 2012

Runtime monitoring is an increasingly popular method to ensure the safe execution of untrusted codes. Monitors observe and transform the execution of these codes, responding when needed to correct or prevent a violation of a user-defined security policy. Prior research has shown that the set of properties monitors can enforce correlates with the latitude they are given to transform and alter the target execution. But for enforcement to be meaningful this capacity must be constrained, otherwise the monitor can enforce any property, but not necessarily in a manner that is useful or desirable. However, such constraints have not been significantly addressed in prior work. In this article, we develop a new paradigm of security policy enforcement in which the behavior of the enforcement mechanism is restricted to ensure that valid aspects present in the execution are preserved notwithstanding any transformation it may perform. These restrictions capture the desired behavior of valid executions of the program, and are stated by way of a preorder over sequences. The resulting model is closer than previous ones to what would be expected of a real-life monitor, from which we demand a minimal footprint on both valid and invalid executions. We illustrate this framework with examples of real-life security properties. Since several different enforcement alternatives of the same property are made possible by the flexibility of this type of enforcement, our study also provides metrics that allow the user to compare monitors objectively and choose the best enforcement paradigm for a given situation.
Creativity-Supporting Learning Environment---CSLE
Authors: Apiola Mikko , Lattu Matti , Pasanen Tomi A.
Published: August 2012

Despite much public discussion about the importance of creativity and innovation-friendly teaching in Finnish higher education, the impact of the general opinion on actual teaching practices has been limited. In the Finnish computer science education the teaching mostly follows a pattern of lectures, fixed exercise sets, and exams. With this article we want to open a discussion about possibilities of enhancing the learning environment by focusing on creative problem solving. We will present results from two research experiments in which we aimed to provide computer science students with a practically oriented learning environment with an explicit intention of supporting the creative work of students. There exists a vast amount of scientific theory about creativity, yet it is unclear on how to turn that theory into practice. Thus, our main interest was to find ways of applying creativity theory in practice in the context of computer science education.

Our research experiments consist of a practically oriented computer science course, where LEGO®Mindstorms robots were used as the platform for the student work. Methodological tools used in this study included content analysis of student products, observations from our learning sessions and semi-structured interviews with the students. The course was organised two times: the first time was in spring 2009 and the second in spring 2010. The total number of attending students was 72.

In this article we argue that our approach of providing a creativity-supporting practical computer science course was a success. We gained a lot of ideas on how to support creativity, the students were clearly motivated, and they began to learn a new kind of experimental working style. The robotics kit seemed to work well both as a trigger for motivation and as a platform to support experimental learning, enhancing students’ creativity and working style.

In our opinion these findings are of great importance, and give promising practical ideas for the support of creativity in higher computer science education.
A New Proof of the Pythagorean Theorem and Its Application to Element Decompositions in Topological Algebras
Authors: Greensite Fred
Published: August 2012

We present a new proof of the Pythagorean theorem which suggests a particular decomposition of the elements of a topological algebra in terms of an “inverse norm” (addressing unital algebraic structure rather than simply vector space structure). One consequence is the unification of Euclidean norm, Minkowski norm, geometric mean, and determinant, as expressions of this entity in the context of different algebras.
Cerebral Arterial Air Embolism Associated with Mechanical Ventilation and Deep Tracheal Aspiration
Authors: Gursoy S. , Duger C. , Kaygusuz K. , Ozdemir Kol I. , Gurelik B. , Mimaroglu C.
Published: August 2012

Arterial air embolism associated with pulmonary barotrauma has been considered a rare but a well-known complication of mechanical ventilation. A 65-year-old man, who had subarachnoid hemorrhage with Glasgow coma scale of 8, was admitted to intensive care unit and ventilated with the help of mechanical ventilator. Due to the excessive secretions, deep tracheal aspirations were made frequently. GCS decreased from 8–10 to 4-5, and the patient was reevaluated with cranial CT scan. In CT scan, air embolism was detected in the cerebral arteries. The patient deteriorated and spontaneous respiratory activity lost just after the CT investigation. Thirty minutes later cardiac arrest appeared. Despite the resuscitation, the patient died. We suggest that pneumonia and frequent tracheal aspirations are predisposing factors for cerebral vascular air embolism.
Robust Control for Systems with Bounded‐Sensor Faults
Authors: Feng Chieh-Chuan
Published: August 2012

In this study an observer‐based novel design of robust control system with an estimate scheme of sensor states to accommodate extended bounded‐sensor faults is proposed. The sensor faults are, in general, modeled as polytopic bounds in robust control framework and are usually given as a priori assumption. But, in practice, the sensors that are subject to faults are especially vulnerable to variant conditions, such as high temperature, and humidity. Thus, their faults may fall outside the presumed polytopic bounds easily. An estimate scheme of sensor states integrated into the observerbased control system captures the sensor faults outside the presumed region. The notion of quadratic stability stabilizes the overall system and guarantees a robust performance measure of an output error signal in the presence of a set of extended admissible sensor faults. A numerical example shows the effectiveness of the proposed approaches.
Nontangential Limits for Modified Poisson Integrals of Boundary Functions in a Cone
Authors: Qiao Lei
Published: August 2012

Our aim in this paper is to deal with non-tangential limits for modified Poisson integrals of boundary functions in a cone, which generalized results obtained by Brundin and Mizuta-Shimomura.
Reciprocal Metabolic Reprogramming through Lactate Shuttle Coordinately Influences Tumor-Stroma Interplay
Authors: Fiaschi Tania , Marini Alberto , Giannoni Elisa , Taddei Maria Letizia , Gandellini Paolo , De Donatis Alina , Lanciotti Michele , Serni Sergio , Cirri Paolo , Chiarugi Paola
Published: August 2012

Cancer-associated fibroblasts (CAF) engage in tumor progression by promoting the ability of cancer cells to undergo epithelial–mesenchymal transition (EMT), and also by enhancing stem cells traits and metastatic dissemination. Here we show that the reciprocal interplay between CAFs and prostate cancer cells goes beyond the engagement of EMT to include mutual metabolic reprogramming. Gene expression analysis of CAFs cultured ex vivo or human prostate fibroblasts obtained from benign prostate hyperplasia revealed that CAFs undergo Warburg metabolism and mitochondrial oxidative stress. This metabolic reprogramming toward a Warburg phenotype occurred as a result of contact with prostate cancer cells. Intercellular contact activated the stromal fibroblasts, triggering increased expression of glucose transporter GLUT1, lactate production, and extrusion of lactate by de novo expressed monocarboxylate transporter-4 (MCT4). Conversely, prostate cancer cells, upon contact with CAFs, were reprogrammed toward aerobic metabolism, with a decrease in GLUT1 expression and an increase in lactate upload via the lactate transporter MCT1. Metabolic reprogramming of both stromal and cancer cells was under strict control of the hypoxia-inducible factor 1 (HIF1), which drove redox- and SIRT3-dependent stabilization of HIF1 in normoxic conditions. Prostate cancer cells gradually became independent of glucose consumption, while developing a dependence on lactate upload to drive anabolic pathways and thereby cell growth. In agreement, pharmacologic inhibition of MCT1-mediated lactate upload dramatically affected prostate cancer cell survival and tumor outgrowth. Hence, cancer cells allocate Warburg metabolism to their corrupted CAFs, exploiting their byproducts to grow in a low glucose environment, symbiotically adapting with stromal cells to glucose availability. Cancer Res; 72(19); 5130–40. ©2012 AACR.
The National Heart, Lung, and Blood Institute Workshop on antihypertensive drug treatment. The benefits, costs, and choices. Implications for research.
Authors: Furberg C D , Cutler J A
Published: August 2012

Selected portions of the workshop's closing discussion are summarized. Major ongoing clinical trials of antihypertensive drug treatment are described. Some recommendations offered by workshop participants for future research directions are summarized.
Blood pressure (systolic and diastolic) and risk of fatal coronary heart disease.
Authors: Stamler J , Neaton J D , Wentworth D N
Published: August 2012

Among the 356,222 men screened for the Multiple Risk Factor Intervention Trial who had no history of hospitalization for heart attack at entry, more than 2,000 coronary deaths occurred during 6 years of follow-up. With this large data set, detailed cross-tabulations clearly and simply showed the strong graded relation between blood pressure and coronary heart disease death. This risk gradient was evident in each of five age groups ranging from 35 to 57 years and for levels of diastolic blood pressure ranging from less than 75 mm Hg to greater than 115 mm Hg. Systolic blood pressure was more strongly associated with coronary heart disease death than was diastolic blood pressure, and isolated systolic blood pressure elevation was found to be an important risk factor in these middle-aged men. The risk of coronary death was increased among hypertensive men who had elevated serum cholesterol levels or who smoked cigarettes. Because less than 10% of hypertensive men had cholesterol levels in the lowest quintile (below 182 mg/dl) and were nonsmokers, a multi-intervention approach for the large majority of hypertensive persons is clearly indicated. Risks of death were also substantially increased among those hypertensive men who already had end-organ damage, emphasizing the importance of early treatment to prevent such damage. These findings have implications for the design of prevention trials and clinical practice, as it is clear that systolic as well as diastolic blood pressure should be considered in treating hypertensive patients. Additionally, treatment goals should be directed at preventing not only death but many other morbid events, clinical and subclinical, that are associated with elevated blood pressure and that are preventable with appropriate treatment.
Changes in hypertension treatment and in congestive heart failure mortality in the United States.
Authors: Yusuf S , Thom T , Abbott R D
Published: August 2012

The use of antihypertensive agents has increased in recent years and has been more marked among individuals in older age groups (65-74 years) than in middle-aged groups (45-54 years). Because hypertension is a strong risk factor for the development of congestive heart failure, more common use of antihypertensive agents would be expected to reduce the incidence of congestive heart failure. Examination of the national death statistics reveals decreases in congestive heart failure mortality at younger ages with mortality increases at older ages. The reasons for these divergent trends in congestive heart failure mortality in different ages and the apparent inconsistency with respect to the changes in the use of antihypertensive drugs are explored. We speculate that antihypertensive treatment does not completely prevent congestive heart failure but merely postpones its development by several decades.
Socioeconomic status in the epidemiology and treatment of hypertension.
Authors: Tyroler H A
Published: August 2012

The association of socioeconomic status (SES), as indexed by educational achievement, with the prevalence, prognosis, and efficacy of treatment of hypertension in the Hypertension Detection and Follow-up Program (HDFP) was reviewed. The prevalence of hypertension varied inversely with SES during the screening program initiated to identify HDFP eligibles in 14 communities in 1973-1974. There was a strong inverse gradient of 5-year all-cause mortality with SES among the hypertensive participants referred to usual care in the HDFP. The association of mortality with SES among hypertensive subjects was eliminated by the HDFP stepped-care program. A large portion of the efficacy of the HDFP was associated with in-trial blood pressure control. Inasmuch as these results are generalizable to the nation, a large fraction of hypertension-associated morbidity and mortality in the United States was related to lower SES in the 1970s, before widespread implementation of programs resulting in increased awareness, treatment, and control of hypertension.