bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effect of Phytohemagglutinin on the Activity of PC-cytidyl Transferase and PC-glyceride Transferase in Cultured Porcine Lymphocytes
Authors: Nelson J. D. , Sribney M.
Published: December 2009

Lymphocytes from the mesenteric lymph nodes of pigs were cultured for 61 h with and without phytohemagglutinin (PHA). Every 12 h the activity of PC-cytidyl transferase (CTP: cholinephosphate cytidylyltransferase, EC 2.7.7.15) and PC-glyceride transferase (CDPcholine: 1,2-diglyceride cholinephosphotransferase, EC 2.7.8.2) was correlated with the incorporation of Me-14C-choline into total lipid. Maximum labelling of total lipid ([Formula: see text] of the label was incorporated into lecithin) occurred between 37 and 48 h of culture. The activity of PC-cytidyl transferase was stimulated up to 10-fold at 37 h while the activity of PC-glyceride transferase exhibited a maximal sixfold increase at 48 h. Addition of actinomycin D (0.10 μg/ml) or cycloheximide (1.0 μg/ml) inhibited simultaneously the induction of the activity of both enzymes and the increased incorporation of 14C-choline into total lipid. It is postulated that the accelerated production of lecithin in PHA-stimulated lymphocytes is dependent on the increased synthesis and/or activity of both these enzymes.
The Control of Alcohol Dehydrogenase Isozyme Synthesis in Saccharomyces cerevisiae
Authors: Fowler P. Wendy , Ball Alan J. S. , Griffiths David E.
Published: December 2009

Isozymes of alcohol dehydrogenase (ADH) from yeast were separated by discontinuous electrophoresis. Three major bands were observed: ADH-I, ADH-II, and a new band designated mito-ADH. Work with isolated mitochondria showed that the mito-ADH band could be produced from physiologically competent mitochondria by mechanical disruption or by treatment with detergents.The isozyme pattern was determined for the various physiological states of yeast growing anaerobically and aerobically on 2% glucose and aerobically on 2% ethanol, and for catabolite de-repressed cells undergoing an anaerobic → aerobic transition in continuous culture.The changing isozyme pattern substantiates the thesis that ADH-I is produced constitutively and that ADH-II is regulated via catabolite repression. It appears from the data that mito-ADH is more closely related to mitochondriogenesis than is ADH-II.
The Number, Location, and Reactivity of the Cysteine Residues of Sturgeon Muscle Aldolase
Authors: Anderson P. J.
Published: December 2009

Sturgeon muscle aldolase contains six cysteine residues per subunit. These residues appear to occur in homologous positions to six of the eight cysteine residues of rabbit muscle aldolase. Three of the six residues can react with either iodoacetic acid or 5,5′-dithiobis-(2-nitrobenzoic acid) in the absence of denaturing agents. Reaction of three residues with iodoacetic acid inactivates the enzyme. The presence of substrate protects one of these residues and in this case no activity loss is observed. However, the results indicate that the effects on activity are due to the addition of the modifying group rather than to a loss of sulfhydryl groups. No residue corresponding to the previously demonstrated substrate-protected cysteine of rabbit aldolase was located in the sturgeon enzyme, which demonstrated that this residue was not essential to aldolase activity. It therefore appears unlikely that cysteine residues have a direct or an auxiliary catalytic role in aldolase activity.
The Effects In Vivo of L- and D-para-Chlorophenylalanine on the Aromatic Hydroxylating Activity of Rat Liver
Authors: Tong J. H. , D'Iorio A. , Benoiton N. Leo
Published: December 2009

Injections of D- or L-p-chlorophenylalanine into rats resulted in identical decreases in the phenylalanine hydroxylase activities of their livers. Similar effects were produced on the ability of the livers to convert L-m-tyrosine to 3,4-dihydroxyphenylalanine. No effects on the tyrosine hydroxylase activities of the brain and adrenals could be detected.
Purification and Properties of Thymidylate Synthetase from Pig Thymus
Authors: Gupta V. S. , Meldrum J. B.
Published: December 2009

Thymidylate synthetase of pig thymus has been separated into two principal forms (designated I and II, based on their order of elution) by chromatography on CM-Sephadex. By the use of (NH4)2SO4 the synthetase activity was separated into two fractions, and these were further purified by gel filtration using Sephadex G-100 and chromatography on CM-Sephadex. The highest specific activity obtained for I and II was 10.4 and 16.3 μmol of thymidine-5′-phosphate per hour per milligram of protein at 25° and pH 7.3 which represents a purification of 1680- and 2630-fold, respectively. Electrophoretically, I and II appear to be 70–80% pure. The Michaelis constants of 7.4 × 10−6 M, 1.7 × 10−5 M, and 1.8 × 10−4 M for II with respect to deoxyuridine-5′-phosphate, 5,10-methlenetetrahydrofolate, and uridine-5′-phosphate, respectively, have been determined. A double pH optima in the range of 6.6–6.8 and 7.2–7.4 in 2-N-morpholinoethane sulfonic acid buffer was exhibited by both forms. Forms I and II showed maximal catalytic activity only in the presence of sulfhydryl compounds (60 mM) and also had the ability to methylate uridine-5′-phosphate, although at a slower rate (ca. 28% and 13%, respectively) compared with the rate of methylation of deoxyuridine-5′-phosphate. Both deoxyuridine-5′-phosphate and tetrahydrofolate (to a lesser extent) afforded protection to II against heat inactivation.
Formation of the δ-Lactone of 3,5-Dihydroxydecanoic Acid by the Fungus Cephalosporium recifei
Authors: Vesonder R. F. , Stodola F. H. , Rohwedder W. K.
Published: December 2009

The fungus Cephalosporium recifei NRRL 5161 produces the δ-lacetone of 3,5-dihydroxydecanoic acid, the structure of which was established by its mass spectrum and its easy dehydration to the lactone of 5-hydroxy-2-decenoic acid.
Phosphorylation of Adenosine and Deoxyadenosine in Ehrlich Ascites Carcinoma Cells Resistant to 6-(Methylmercapto)purine Ribonucleoside
Authors: Lomax Christopher A. , Henderson J. Frank
Published: December 2009

The metabolism of adenosine and deoxyadenosine has been studied in Ehrlich ascites tumor cells and in a subline (EAC-R2) resistant to growth inhibition by 6-(methylmercapto)purine ribonucleoside (6MeMPR). The mutant cell line showed reduced rates of conversion of adenosine and deoxyadenosine into nucleotides. It was concluded from this that both compounds probably are phosphorylated by adenosine kinase. Comparison of the rates of nucleotide synthesis at increasing concentrations of adenosine indicated differences in the Km and Vmax values of the adenosine kinases in the parent and mutant strains. Competition experiments between adenosine and 6MeMPR showed that adenosine kinase in EAC-R2 had probably lost all affinity for the analogue. Selection for resistance to 6MeMPR therefore seems to have altered the structure of adenosine kinase, such that it has no activity with 6MeMPR and reduced activity with adenosine and deoxyadenosine.
Association of Neutral Lipids with Phospholipids
Authors: Rubenstein Bernard , Lombardi Benito
Published: December 2009

An association between emulsified triglycerides and microsomes retaining phospholipid and ATPase activity has been demonstrated. The association required divalent cations, which cannot be replaced by monovalent cations. Purified membrane phospholipid or egg lecithin suspended by hand homogenation can substitute for intact membranes. The association may serve as a model for neutral lipid–phospholipid association seen in the serum lipoproteins.
Effect of Estrogens on Rat Serum Lipoproteins
Authors: Hill P. , Martin W. G.
Published: December 2009

Estrogens, ingredients of contraceptive drugs, were found to affect serum lipids, lipoproteins, and liver lipids of rats selectively. Subcutaneous administration of ethynylestradiol reduced the phospholipid content of the dextran sulfate soluble fraction (HDS) of the serum and decreased the rate of disappearance of the phospholipid moiety, labelled with choline-Me3H in this fraction. Estradiol-17β increased the HDS phospholipid but not its rate of turnover. On analytical ultracentrifugation of the whole serum, no low density lipoprotein was detected and the high density lipoprotein was reduced in ethynylestradiol-treated rats. Ethynylestradiol decreased the phospholipid content and turnover of lecithin in the liver. Both ethynylestradiol and estradiol-17β quantitatively increased the very low density lipoprotein, increasing the phospholipid and triglyceride contents. Data suggested that ethynylestradiol and estradiol-17β affected phospholipid synthesis in the liver to different degrees and one result of this was a change in the proportion of phospholipid in the high density lipoprotein in the rat.
New Analogues of Aspergillic Acid Derived from Methionine
Authors: MacDonald J. C.
Published: December 2009

Aspergillus flavus PRL 932 grown on 2% yeast extract plus 1% methionine produced some compounds which, according to their structures, were probably derived in part or completely from methionine. These included 3-(methylthio)-propionic acid, trans-3-(methylthio)-acrylic acid, and various 1-hydroxy-2(1H)-pyrazinones (HPY) with 2-(methylthio)-ethyl (MTE) substituents. The latter compounds were identified by proton magnetic resonance and mass spectra as 3,6-di-MTE-HPY, 3-MTE-6-isopropyl-HPY, 3-isobutyl-6-MTE-HPY, 3-MTE-6-isobutyl-HPY, and 3-MTE-6-sec-butyl-HPY.Changes in media composition, including supplementation with either L-leucine, L-isoleucine, or L-valine changed the relative amounts of various HPYs produced. The results indicated that amino acids competed as precursors for the biosynthesis of HPYs and that L-leucine and L-isoleucine were utilized more effectively than was L-methionine.
Energy Metabolism of the Skeletal Muscle of Genetically Dystrophic Hamster
Authors: Dhalla Naranjan S. , Fedelesova Margaret , Toffler Ivan
Published: December 2009

The hind leg skeletal muscles of about 215-day-old genetically dystrophic hamsters (BIO strain 14.6) were found to contain subnormal concentrations of creatine phosphate, ATP, total adenine nucleotides, and NAD+ in comparison with those from the control animals. On the other hand, the levels of lactate, NADH, and NADPH were elevated without any significant changes in pyruvate, AMP, ADP, and NADP+ in the dystrophic muscle. The ratios of ATP/ADP and ATP/AMP were decreased and those of lactate/pyruvate, NADH/NAD+, and NADPH/NADP+ were increased in the dystrophic muscle. There are a number of similarities between the dystrophic and asphyxiated muscles with respect to energy metabolism; however, the possibility is not ruled out at present that the hypoxic-like changes in energy metabolism of the dystrophic muscle are due to mechanisms other than oxygen lack. The activity of glucose-6-phosphate dehydrogenase was increased whereas the activities of α-glycerophosphate dehydrogenase, glyceraldehyde phosphate dehydrogenase, lactate dehydrogenase, myokinase, and creatine phosphokinase were decreased in the dystrophic muscle. On the basis of our earlier and present results it is suggested that changes in the high energy phosphate stores in the genetically dystrophic hamster muscle are due to defects in both the processes of energy production and utilization.
Synthesis of Uridine 5′-(L-Arabinofuranosyl pyrophosphate) and the Structure of the UDP-L-arabinose Formed in Plants from UDP-α-D-xylopyranose
Authors: Aspinall G. O. , Cottrell I. W. , Matheson N. K.
Published: December 2009

Uridine 5′-(L-arabinofuranosyl pyrophosphate) and uridine 5′-(β-L-arabinopyranosyl pyrophosphate) have been synthesized chemically and compared with the UDP-L-arabinose formed from UDP-α-D-xylopyranose and UDP-α-D-glucuronic acid by plant particulate fractions. It is concluded that the product of enzymic reaction has a pyranose ring structure.
Studies on the Incorporation of Amino Acids by a Cell-Free System Obtained from Beef Retina
Authors: Matuk Y.
Published: December 2009

The incorporation of 14C-leucine into proteins by a cell-free system from beef retina was studied. It was found that the optimum concentration of ATP depended on the concentration of ribosomes in the incubation medium. Very little incorporation of 14C-leucine was observed in the absence of K+. The optimum concentration of phosphocreatine required for incorporation of radioactive leucine depended on the concentration of Mg2+ in the incubation medium, and the optimum concentration of K+ appears to be independent of the concentrations of Mg2+ and phosphocreatine used.Retinol and retinal had no effect, but ethanol markedly inhibited protein synthesis at concentrations higher than 2%.Puromycin (10−4 M) inhibited incorporation of 14C-leucine by about 80%. The degree of inhibition by cycloheximide depended on the concentration of pH 5 fraction in the incubation medium.
Aldehyde Dehydrogenases in Rat Liver
Authors: Shum G. T. , Blair A. H.
Published: December 2009

Two enzymes (I and II) with NAD+-dependent aldehyde dehydrogenase activity have been separated and partially purified from the supernatant fraction of rat liver. Resolution was effected by DEAE-cellulose column chromatography. In addition to the differences in charge properties, these two proteins differ in substrate specificity, that of enzyme II being comparatively restricted. Enzyme I has a relatively sharp optimum in activity at pH 8 whereas enzyme II exhibits an optimal range between pH 8 and 9.5. Both enzymes are strongly inhibited by low concentrations of p-chloromercuribenzene sulfonic acid and this inhibition can be reversed by dithiothreitol. Both enzymes are also inhibited by arsenite; inhibition of enzyme I is enhanced by mercaptoethanol but inhibition of enzyme II is not so affected. Molecular weight estimation by gel filtration indicates each protein has a molecular weight of approximately 180 000.
A Proton Magnetic Resonance Study of the Influence of Base Ionization on the Conformation of Pseudouridine
Authors: Deslauriers Roxanne , Smith Ian C. P.
Published: December 2009

The proton magnetic resonance spectra of alkaline deuterium oxide solutions of α-pseudouridine (α-ψ), β-pseudouridine (β-ψ), and 1-(β-D-ribofuranosyl)-cyanuric acid (β-CAR) are analyzed to explore the possibility that conformational changes are responsible for the unusual ultraviolet spectra of β-ψ at high pH. The largest change in ribose ring conformation due to increased alkalinity is observed in β-ψ; the ribose ring, although interconverting between various puckered forms, shows a slight preference for the 2′-endo and 3′-exo conformations. There is also a preference by α-ψ and β-ψ for the gauche-gauche rotamers about the exocyclic C4′–C5′ bond; this preference is not shown by β-CAR. No change occurs in the chemical shifts of the protons of α-ψ and β-ψ on going from neutral or acidic to basic solution. Increasing temperature to 60 °C causes no significant change in either coupling constants or chemical shifts. Comparison of chemical shifts observed in β-ψ with those found in β-CAR leads us to believe that the base remains in the anti conformation with respect to the ribose ring and is therefore incapable of forming a hydrogen bond with the exocyclic hydroxyl group as had been postulated previously to explain anomalous ultraviolet spectral data. A weak hydrogen bond between the 5′-hydroxymethyl group and the 5–6 double bond remains as a plausible explanation for the unusual ultraviolet spectra.
Studies on Acute Phase Proteins of Rat Serum. I. Isolation and Partial Characterization of an α1-Acid Glycoprotein and an α2-Macroglobulin
Authors: Jamieson J. C. , Friesen A. D. , Ashton F. E. , Chou B.
Published: December 2009

An α1-acid glycoprotein and an α2-macroglobulin were isolated from serum from rats suffering from experimentally induced inflammation for 48 h. The proteins were characterized electrophoretically and immunologically and their carbohydrate compositions and some physical properties determined. The α1-acid glycoprotein contained 34.1% carbohydrate, had an isoelectric point of 2.95, and a molecular weight of 43 000. The α2-macroglobulin contained 15.9% carbohydrate, had an isoelectric point of 4.60, and a molecular weight of about 800 000. The properties of the two proteins are compared with those of similar proteins isolated from rats and other species.
The Processing of Polyoma Virus RNA Synthesized during Productive Infection in Mouse Cells
Authors: Petric Martin , Hudson James B.
Published: December 2009

An examination was made of the intracellular distribution of polyoma (Py) virus RNA molecules synthesized late during productive infection in mouse cells. The Py-specific RNA from whole cells, and their nuclear, cytoplasmic, and polyribosome fractions, were compared with respect to sedimentation behavior (on sucrose gradients), electrophoretic mobility (on polyacrylamide gels), and base sequence homology (by competitive hybridization tests). Sedimentation and electrophoretic analysis revealed marked heterogeneity in PyRNA from all cell fractions. This heterogeneity and relative size distribution were essentially the same on dimethyl sulfoxide – sucrose gradients. The PyRNA from different regions of a sucrose gradient contained common sequences, as revealed by cross competition – hybridization experiments. However, the poly-ribosome-associated PyRNA was devoid of the > 28 S species found in the other fractions. Thus, it appears that PyRNA, including RNA of apparent size in excess of one genome length, is synthesized in the nucleus and cleaved to smaller pieces in association with polyribosomes.
Biosynthesis of Phosphatidic Acid in Mitochondria and Microsomes Via the Acylation of sn-Glycero-3-phosphate
Authors: Davidson J. B. , Stanacev N. Z.
Published: December 2009

Nuclei-free homogenate, prepared from guinea pig livers, was fractionated into subcellular particles which were then examined for the activities of two microsomal marker enzymes, glucose-6-phosphatase and NADPH: cytochrome c reductase. In an incubation system containing sn-glycero-3-phosphate, fatty acid, and various cofactors the intracellular distribution of acyl-CoA: sn-glycero-3-phosphate acyltransferase(s) was studied and compared with the distribution of the two microsomal marker enzymes.Results obtained showed that the highest specific activity for the acylation of sn-glycero-3-phosphate was associated with the microsomal fraction and the activity in each subcellular fraction paralleled activities of the two microsomal marker enzymes. Furthermore, the amount of acyl-CoA: sn-glycero-3-phosphate acyltransferase activity observed in the mitochondrial and submitochondrial fractions could be accounted for by the content of endoplasmic reticulum as determined by the marker enzymes. This observation was also true for brain, heart, and kidney, as well as for rat liver.These results are interpreted as evidence that isolated mitochondria are unable to synthesize phosphatidic acid by direct acylation of sn-glycero-3-phosphate.
Adenylate-Rich Oligonucleotides from Ribosomal RNA of Animal Cells
Authors: Birnboim H. C.
Published: December 2009

A mixture of oligonucleotides has been prepared from animal cell ribosomal RNA by treatment with pancreatic and T1 ribonucleases. Tetra-, penta-, and hexanucleotides from this digest have been fractionated and analyzed. In addition to the expected components having the nucleotide sequence (Ap)nCp, (Ap)nUp, and (Ap)nGp, others contain sugar- and base-methylated residues. Some of the oligonucleotides are found only in 18 S RNA and others only in 28 S RNA. The patterns are distinctive and can be used as biochemical markers for distinguishing between the two RNA species. Evidence is presented which suggests that ribosomal RNA is heterogeneous with respect to some of these components.
An Endodeoxyribonuclease Induced after Infection with Phage T7 Bearing Amber Mutations in Genes 3, 5, and 6
Authors: Sadowski Paul D.
Published: December 2009

An endodeoxyribonuclease activity was detectable in extracts from E. coli 1200 (su−, Endo I−) cells infected with T7 phage bearing amber mutations in genes 3, 5, and 6. The enzyme was purified 270-fold and it makes predominantly single-stranded breaks in native DNA. The breaks have 3′-hydroxyl and 5′-phosphoryl termini and the endonuclease acts almost as well on denatured DNA as on native DNA. The function of the enzyme is not known but its activity does not appear to be controlled by genes involved in replication or maturation of phage DNA.
Evidence against the Involvement of Mutarotase in the D-Glucose Uptake Activity of Isolated Human Erythrocyte Membranes
Authors: Kahlenberg Arthur , Miller Gary
Published: December 2009

Mutarotase, the enzyme catalyzing the interconversion of the anomeric forms of D-glucose, has recently been suggested to be the membrane glucose carrier in human erythrocytes. However, hemoglobin-free human erythrocyte membranes possessing D-glucose uptake activity were found to be free of mutarotase activity. Mutarotase activity was detected in the membrane-free hemolysates of the cells. It is therefore concluded that the D-glucose uptake activity of isolated erythrocyte membranes is not due to the binding of the sugar to mutarotase, and that this enzyme is not involved in glucose transport in a manner compatible with most presently held concepts of the membrane transport process.
Sulfhydril Groups and the Concerted Inhibition of NADP+-Linked Isocitrate Dehydrogenase
Authors: Little Clive , Holland Peggy
Published: December 2009

Mixtures of glyoxalate and oxaloacetate have been shown to inhibit highly purified pig heart NADP+ -linked isocitrate dehydrogenase in a strongly concerted manner. The α-ketoglutarate reductive carboxylase activity of the enzyme was also inhibited, but to a lesser extent than the dehydrogenase activity. Modification of sulfhydryl groups in the enzyme by certain reagents led to a diminution of the inhibition, although the extent of this effect depended on the reagent used. N-Ethylmaleimide was most effective at diminishing the concerted inhibition, whereas oxidation of the sulfhydryl groups by X-irradiation or lipid peroxide had no effect. It was concluded that the effect of sulfhydryl reagents on the inhibition was probably due to the modification of one specific cysteine residue which is possibly adjacent to the binding site on the enzyme for glyoxalate.
COSMO-PARTICLE SEARCHES FOR SUPERSYMMETRY AT THE COLLIDER DETECTOR AT FERMILAB
Authors: TOBACK DAVID
Published: December 2009

Some theories of particle physics are so compelling that it is worth doing a comprehensive and systematic set of experimental searches to see if they are realized in nature. Supersymmetry is one such theory. This review focuses on the motivation for a broad set of cosmology-inspired search strategies at the Tevatron and on their implementation and results at the Collider Detector at Fermilab (CDF) with the first few fb-1 of integrated luminosity of data.
HE'S HOMOTOPY PERTURBATION METHOD FOR A GENERAL RICCATI EQUATION
Authors: ÖZIŞ TURGUT , AĞIRSEVEN DENIZ
Published: December 2009

The factorization method of the Hamiltonian in quantum mechanics is used to solve a particular type of Riccati equation. In this paper, He's homotopy perturbation method is applied to a general Riccati equation. The obtained solutions are in recursive sequence forms and, in many cases, these solutions lead to an exact solution. This property generally means that one can solve completely the eigenvalue problem for the Hamiltonian operator. The method is tested on various examples which are revealing the effectiveness and the simplicity of the method.
MECHANICAL AND ELECTRICAL RESONANCE IN ASSIGNMENT OF THE AGE OF WALL PAINTS
Authors: ZORIĆ VOJKAN M. , SAJFERT VJEKOSLAV , MAŠKOVIĆ LJILJANA , ZORIĆ JELENA
Published: December 2009

In this work the mechanism of resonance is proposed as the way for determining of wall paint age. The method consists in accelerated growing old of wall paint on the basis of resonance. Measuring is concerned with the humidity of wall paint and it is a general method since water molecules are present in every material. Besides, the water molecules are dipoles so that the resonance with them can be achieved by the mechanical as well as the electrical way.
EFFECTS OF SAMPLE-SPECIFIC VARIATIONS AND FLUCTUATIONS OF THERMAL OCCUPANCY ON FLUCTUATIONS OF THERMODYNAMIC QUANTITIES
Authors: SEROTA R. A.
Published: December 2009

Standard results for the fluctuations of thermodynamic quantities are derived under the assumption of sampling identical systems that are in different, not fully equilibrated states. These results apply to fluctuations with time in a particular macroscopic body and can be traced to the fluctuations of thermal occupancy. When many identically prepared — but not identical — systems are studied, mesoscopic fluctuations due to variations from sample-to-sample contribute to the fluctuations of thermodynamic quantities. We study the combined effect of mesoscopic fluctuations and fluctuations of thermal occupancy. In particular, we evaluate the total particle number and specific heat fluctuations in a two-dimensional, noninteracting electron gas in classically integrable and chaotic circumstances.
LOW RANK VECTOR BUNDLES ON THE GRASSMANNIAN G(1,4)
Authors: MALASPINA FRANCESCO
Published: December 2009

Here we define the concept of L-regularity for coherent sheaves on the Grassmannian G(1,4) as a generalization of Castelnuovo–Mumford regularity on Pn. In this setting we prove analogs of some classical properties. We use our notion of L-regularity in order to prove a splitting criterion for rank 2 vector bundles with only a finite number of vanishing conditions. In the second part, we give the classification of rank 2 and rank 3 vector bundles without "inner" cohomology (i.e. [Formula: see text] for any i = 2,3,4) on G(1,4) by studying the associated monads.
THE TWO WAYS OF GAUGING THE POINCARÉ GROUP
Authors: SPIRO A. , TANTUCCI S.
Published: December 2009

A description of how a theory of gravity can be considered as a gauge theory (in the sense of Trautman) of the Poincaré group is given. As a result, it is shown that a gauge theory of this kind is consistent with the Equivalence Principle only if the Lagrangian and the constraints are preserved not only by the gauge transformations but also by an additional family of transformations, called pseudo-translations. Explicit expressions of pseudo-translations and of their action on gravitational gauge fields are given. They are expected to be useful for geometric interpretations of their analogues in supergravity theories.
EXTENDED AFFINE CLASSES OF LAGRANGIANS AND HAMILTONIANS RELATED TO CLASSICAL FIELD THEORIES
Authors: UDRIŞTE CONSTANTIN , POPESCU MARCELA , POPESCU PAUL
Published: December 2009

The aim of the paper is to establish a natural affine frame for affine Lagrangians and Hamiltonians, generalizing the well-known classical field theory. Scalar and volume-valued Lagrangians and Hamiltonians can be lifted to the new classes. Using the Hamilton–Jacobi principle, we analyze variational problems corresponding to actions defined by the affine Lagrangians and Hamiltonians. The extremals verify generalizations of the Euler–Lagrange and De Donder–Weyl PDEs. They improve the information about the dynamical solutions of the classical variational problems and refresh the Lagrange–Hamilton theories.
THE RELATIVE ENERGY OF HOMOGENEOUS AND ISOTROPIC UNIVERSES FROM VARIATIONAL PRINCIPLES
Authors: BIBBONA ENRICO , FATIBENE LORENZO , FRANCAVIGLIA MAURO
Published: December 2009

We calculate the relative conserved currents, superpotentials and conserved quantities between two homogeneous and isotropic universes. In particular, we prove that their relative "energy" (defined as the conserved quantity associated to cosmic time coordinate translations for a comoving observer) is vanishing and so are the other conserved quantities related to a Lie subalgebra of vector fields isomorphic to the Poincaré algebra. These quantities are also conserved in time. We also find a relative conserved quantity for such a kind of solution which is conserved in time though non-vanishing. This example provides at least two insights in the theory of conserved quantities in General Relativity. First, the contribution of the cosmological matter fluid to the conserved quantities is carefully studied and proved to be vanishing. Second, we explicitly show that our superpotential (that happens to coincide with the so-called KBL potential although it is generated differently) provides strong conservation laws under much weaker hypotheses than the ones usually required. In particular, the symmetry generator is not needed to be Killing (nor Killing of the background, nor asymptotically Killing), the prescription is quasi-local and it works fine in a finite region too and no matching condition on the boundary is required.
CONSTRAINT ALGORITHM FOR EXTREMALS IN OPTIMAL CONTROL PROBLEMS
Authors: BARBERO-LIÑÁN MARÍA , MUÑOZ-LECANDA MIGUEL C.
Published: December 2009

A geometric method is described to characterize the different kinds of extremals in optimal control theory. This comes from the use of a presymplectic constraint algorithm starting from the necessary conditions given by Pontryagin's Maximum Principle. The algorithm must be run twice so as to obtain suitable sets that once projected must be compared. Apart from the design of this general algorithm useful for any optimal control problem, it is shown how to classify the set of extremals and, in particular, how to characterize the strict abnormality. An example of strict abnormal extremal for a particular control-affine system is also given.
Recent studies chemical sensors based on phthalocyanines
Authors: Öztürk Zafer Ziya , Kılınç Necmettin , Atilla Devrim , Gürek Ayşe Gül , Ahsen Vefa
Published: December 2009

Phthalocyanines (Pcs) are organic compounds able to act as chemical recognition systems because of the various physical effects induced in them by interaction with a large number of gases. The gas response, stability and other sensing characteristics of the Pc films are affected by many factors, such as film morphology, molecular orientation and so on. The interaction between the Pc coatings and the gas molecules may be classified in terms of irreversible chemical affinity, reversible (usually charge transfer) chemical reaction or sorption. The nature of the interactions between the coating and vapor molecules determines the selectivity, sensitivity, signal kinetics, and the reversibility of the sensor. The magnitude of these interactions may be conveniently described in the frame of the linear sorption energy relationship (LSER) model that has been shown to be very efficient at predicting the behavior of polymer-based sensors. In this paper, the effect of coating parameters on sensing properties and sensing mechanism are reviewed. We have proposed an alternative way to achieve optimal sensor performance: liquid crystalline Pcs forming self-ordered thin films of defined area and thickness simply by heating the sample over the phase transition temperature and synthetized mesomorphic and functionalized phthalocyanines, to develop sensors based on mass-sensitive transducers (quartz crystal microbalance, QCM). Phthalocyanines used are discussed in terms of their physical and chemical properties, as well as their sensing properties: sensitivity, selectivity and reversibility. We showed our results with LSER and the results are in good agreement with this theory.
RECENT STUDY ON THE RELATED PROBLEMS IN EVALUATION OF MECHANICAL PROPERTIES FOR MEMS MATERIALS
Authors: JIANG ZHUANGDE , ZHOU XIANGYANG , ZHU QIANG , ZHAO ZEXIANG , HAIRONG WANG , PREWETT PHILIP D. , JIANG KYLE
Published: December 2009

In order to obtain reliable evaluation result by nanoindentation, the related problems during measurement of the hardness and elastic modulus are investigated. Two quantitative approaches, i.e. calculating actual contact area and correcting contact depth errors, are proposed to deal with the significant pile-up errors for indentation on those ductile soft materials, especially thin soft metal films on hard substrates. The various influence factors during indentation are analyzed, and a new method for uncertainty estimation in hardness and elastic modulus is provided based on the random-fuzzy variables. Through the illustration of Au/glass-ceramic and Al/7059 glass, both the quantitative approaches are suitable for the elastically matching film-substrate systems. The measurement uncertainties in hardness and elastic modulus of Si(100) are effectively estimated, and all possible influencing effects on uncertainty can be involved.
A DUAL-PERMEABILITY NETWORK MODEL FOR MULTILAYER WOVEN FABRICS
Authors: CHEN ZUO-RONG , LU MENG , YE LIN
Published: December 2009

An analytical permeability model is formulated for multilayer plain woven fabrics based on a network treatment. Both meso-scale flow between fibre tows and micro-scale flow within tows are taken into account, addressing the effects of meso-/micro-structures of fabrics. For a single layer fabric, open channels between adjacent fibre tows and between fibre tows and surface boundaries have a significant effect on in-plane permeability, while out-of-plane permeability is sensitive to open gaps between tows. It is shown that the permeability of multilayer woven fabrics may differ significantly from that of a single layer, depending on the meso-/micro-structures of multilayer fabrics. Two major mechanisms are found to affect the in-plane permeability of multilayer fabrics in opposite ways. As the number of layers increases, the large inter-layer open channels created after laying-up result in an increase in in-plane permeability; on the other hand, reduction of inter-layer open channels due to nesting during a compaction process leads to a decrease in in-plane permeability. In addition, reduction of trans-layer open channels due to inter-layer blocking associated with shifting also greatly reduces the out-of-plane permeability of multilayer fabrics. Predictions from the permeability model offer satisfactory agreement with the experimental data and the predictions based on finite element analysis.
GENERALIZATION OF THE SERRE-SWAN-MALLIOS THEOREM FOR SHEAVES AND PRESHEAVES
Authors: Abel Mart
Published: December 2009

In the present paper we give the versions of generalized Serre-Swan-Mallios Theorem for sheaves and presheaves. In order to do it, we introduce new classes of sheaves and presheaves, called suitable sheaves and suitable presheaves.
CHORD POWER INTEGRALS OF SIMPLICES
Authors: Cheung Wing-Sum , Xiong Ge
Published: December 2009

In this paper, we obtain a formula relating the chord power integrals of a simplex K and the dual quermassintegrals of its difference body DK. As interesting applications, we express the volumes of difference body DK and polar projection body Π*K in terms of the volume of simplex K. Santaló-type inequality for chord power integrals of simplex is also established.
APPLICATION OF EXP-FUNCTION METHOD TO REDUCED OSTROVSKY EQUATION AND KURAMOTO-SIVASHINSKY EQUATION
Authors: Ganji D. D. , Babaelahi M. , Joneidi A. A. , Davodi A. G.
Published: December 2009

In this paper, a kind of analytical technique, called Exp-Function method is implemented to find the solitary wave solution of the Kuramoto-Sivashinsky equation and some of the most useful equations in physics, the Camassa-Holm equation and the reduced Ostrovsky equation (ROE). This method can be used as an alternative to obtain analytic and approximate solutions of different types of fractional differential equations applied in engineering mathematics. Some numerical examples are presented to illustrate the efficiency and reliability of the Exp-Function method. It is predicted that Exp-Function method can be found widely applicable in engineering.
HOMOTOPY PERTURBATION METHOD FOR SOLVING SYSTEMS OF PARTIAL DIFFERENTIAL EQUATIONS
Authors: Mohyud-Din Syed Tauseef , Yildirim Ahmet
Published: December 2009

In this paper, we apply the homotopy perturbation method (HPM) for solving systems of partial differential equations. The proposed iterative scheme finds the solution without any discretization, linearization or restrictive assumptions. Several examples are given to verify the reliability and efficiency of the method. The fact that the suggested technique solves nonlinear problems without using the Adomian's polynomials is an advantage of this algorithm over the decomposition method.
FINITE GROUPS WITH SOME SEMI-p-COVER-AVOIDING OR S-QUASINORMALLY EMBEDDED SUBGROUPS
Authors: Qiao Shouhong , Wang Yanming
Published: December 2009

A subgroup H of a group G is called S-quasinormally embedded in G if, for each prime p dividing the order of H, a Sylow p-subgroup of H is a Sylow p-subgroup of an S-quasinormal subgroup of G. H is said to be semi-p-cover-avoiding in G if there is a chief series 1 = G0 < G1 < ⋯ < Gt = G of G such that, for every i = 1, 2, ⋯, t, if Gi/Gi-1 is a p-chief factor, then H either covers or avoids Gi/Gi-1. We give the structure of a finite group G in which some subgroups of G with prime-power order are either semi-p-cover-avoiding or S-quasinormally embedded in G.
Calcium signaling via two-pore channels: local or global, that is the question
Authors: Zhu Michael X. , Ma Jianjie , Parrington John , Calcraft Peter J. , Galione Antony , Evans A. Mark
Published: December 2009

Recently, we identified, for the first time, two-pore channels (TPCs, TPCN for gene name) as a novel family of nicotinic acid adenine dinucleotide phosphate (NAADP)-gated, endolysosome-targeted calcium release channels. Significantly, three subtypes of TPCs have been characterized, TPC1-3, with each being targeted to discrete acidic calcium stores, namely lysosomes (TPC2) and endosomes (TPC1 and TPC3). That TPCs act as NAADP-gated calcium release channels is clear, given that NAADP binds to high- and low-affinity sites associated with TPC2 and thereby induces calcium release and homologous desensitization, as observed in the case of endogenous NAADP receptors. Moreover, NAADP-evoked calcium signals via TPC2 are ablated by short hairpin RNA knockdown of TPC2 and by depletion of acidic calcium stores with bafilomycin. Importantly, however, NAADP-evoked calcium signals were biphasic in nature, with an initial phase of calcium release from lysosomes via TPC2, being subsequently amplified by calcium-induced calcium release (CICR) from the endoplasmic reticulum (ER). In marked contrast, calcium release via endosome-targeted TPC1 induced only spatially restricted calcium signals that were not amplified by CICR from the ER. These findings provide new insights into the mechanisms that cells may utilize to “filter” calcium signals via junctional complexes to determine whether a given signal remains local or is converted into a propagating global signal. Essentially, endosomes and lysosomes represent vesicular calcium stores, quite unlike the ER network, and TPCs do not themselves support CICR or, therefore, propagating regenerative calcium waves. Thus “quantal” vesicular calcium release via TPCs must subsequently recruit inositol 1,4,5-trisphoshpate receptors and/or ryanodine receptors on the ER by CICR to evoke a propagating calcium wave. This may call for a revision of current views on the mechanisms of intracellular calcium signaling. The purpose of this review is, therefore, to provide an appropriate framework for future studies in this area.
Connective tissue growth factor (CTGF/CCN2) is increased in peritoneal dialysis patients with high peritoneal solute transport rate
Authors: Mizutani Makoto , Ito Yasuhiko , Mizuno Masashi , Nishimura Hayato , Suzuki Yasuhiro , Hattori Ryohei , Matsukawa Yoshihisa , Imai Masaki , Oliver Noelynn , Goldschmeding Roel , Aten Jan , Krediet Raymond T. , Yuzawa Yukio , Matsuo Seiichi
Published: December 2009

Peritoneal fibrosis (PF) is an important complication of peritoneal dialysis (PD) therapy that often occurs in association with peritoneal high transport rate and ultrafiltration failure (UFF). To study the possible pathogenic role of connective tissue growth factor (CTGF) in the relationship of PF and UFF, dialysate CTGF contents ( n = 178) and tissue CTGF expression ( n = 61) were investigated by ELISA, real-time PCR, immunohistochemistry, and in situ hybridization. CTGF production with and without TGF-β1stimulation in human peritoneal mesothelial cells (HPMC) from the spent patients' peritoneal dialysate ( n = 32) was studied in vitro. The dialysate-to-plasma ratio for creatinine (D/P Cr) was positively correlated to dialysate CTGF concentration and estimated local peritoneal production of CTGF. CTGF mRNA expression was 11.4-fold higher in peritoneal membranes with UFF than in pre-PD renal failure peritoneum and was correlated with thickness of the peritoneum. CTGF protein and mRNA were detected in mesothelium and in fibroblast-like cells. In cultured HPMC, TGF-β1-induced expression of CTGF mRNA was increased at 12 and 24 h and was correlated with D/P Cr. In contrast, bone morphogenic protein-4 mRNA expression was inversely correlated with D/P Cr. Our results suggest that high peritoneal transport state is associated with fibrosis and increased peritoneal CTGF expression and production by mesothelial cells, which can be stimulated by TGF-β1. Dialysate CTGF concentration could be a biomarker for both peritoneal fibrosis and membrane function. Functional alteration of mesothelial cells may be involved in progression of peritoneal fibrosis in high transport state.
Roll-Dependent Modulation of the Subjective Visual Vertical: Contributions of Head- and Trunk-Based Signals
Authors: Tarnutzer A. A. , Bockisch C. J. , Straumann D.
Published: December 2009

Precision and accuracy of the subjective visual vertical (SVV) modulate in the roll plane. At large roll angles, systematic SVV errors are biased toward the subject's body-longitudinal axis and SVV precision is decreased. To explain this, SVV models typically implement a bias signal, or a prior, in a head-fixed reference frame and assume the sensory input to be optimally tuned along the head-longitudinal axis. We tested the pattern of SVV adjustments both in terms of accuracy and precision in experiments in which the head and the trunk reference frames were not aligned. Twelve subjects were placed on a turntable with the head rolled about 28° counterclockwise relative to the trunk by lateral tilt of the neck to dissociate the orientation of head- and trunk-fixed sensors relative to gravity. Subjects were brought to various positions (roll of head- or trunk-longitudinal axis relative to gravity: 0°, ±75°) and aligned an arrow with perceived vertical. Both accuracy and precision of the SVV were significantly ( P < 0.05) better when the head-longitudinal axis was aligned with gravity. Comparing absolute SVV errors for clockwise and counterclockwise roll tilts, statistical analysis yielded no significant differences ( P > 0.05) when referenced relative to head upright, but differed significantly ( P < 0.001) when referenced relative to trunk upright. These findings indicate that the bias signal, which drives the SVV toward the subject's body-longitudinal axis, operates in a head-fixed reference frame. Further analysis of SVV precision supports the hypothesis that head-based graviceptive signals provide the predominant input for internal estimates of visual vertical.
Varying Overall Sound Intensity to the Two Ears Impacts Interaural Level Difference Discrimination Thresholds by Single Neurons in the Lateral Superior Olive
Authors: Tsai Jeffrey J. , Koka Kanthaiah , Tollin Daniel J.
Published: December 2009

The lateral superior olive (LSO) is one of the earliest sites in the auditory pathway involved in processing acoustical cues to sound location. LSO neurons encode the interaural level difference (ILD) cue to azimuthal location. Here we investigated the effect of variations in the overall stimulus levels of sounds at the two ears on the sensitivity of LSO neurons to small differences in ILDs of pure tones. The neuronal firing rate versus ILD functions were found to depend greatly on the overall stimulus level, typically shifting along the ILD axis toward the excitatory ear and attaining greater maximal firing rates as stimulus level increased. Seventy-five percent of neurons showed significant shifts with changes in overall sound level. The range of ILDs corresponding to best neural acuity for ILDs shifted accordingly. In a simulation using the empirical data, when the overall stimulus level was randomly changed from one trial to the next, the neural discrimination thresholds for ILD, or ILD acuities, were worsened by 50–60% across the population of neurons relative to fixed stimulus levels whether ILD acuity was measured at the azimuthal midline or the ILD pedestal producing the best acuity. The impairment in ILD discrimination was attributed to the increased neural response variance imparted by varying the stimulus level. These results contrast to those observed in psychophysical studies where ILD discrimination thresholds under similar experimental conditions are invariant to overall changes in stimulus level. A simple computational model that incorporated the antagonistic inputs of bilateral LSO nuclei as well as the dorsal nuclei of the lateral lemniscus to the inferior colliculus produced a more robust encoding of ILD even in the setting of roving stimulus level. Testable predictions of this model and comparison to other computational models addressing stimulus invariance were considered.
Nature versus Nurture in Shallow Convection
Authors: Romps David M. , Kuang Zhiming
Published: December 2009

Tracers are used in a large-eddy simulation of shallow convection to show that stochastic entrainment (and not cloud-base properties) determines the fate of convecting parcels. The tracers are used to diagnose the correlations between a parcel’s state above the cloud base and both the parcel’s state at the cloud base and its entrainment history. The correlation with the cloud-base state goes to zero a few hundred meters above the cloud base. On the other hand, correlations between a parcel’s state and its net entrainment are large. Evidence is found that the entrainment events may be described as a stochastic Poisson process. A parcel model is constructed with stochastic entrainment that is able to replicate the mean and standard deviation of cloud properties. Turning off cloud-base variability has little effect on the results, which suggests that stochastic mass-flux models may be initialized with a single set of properties. The success of the stochastic parcel model suggests that it holds promise as the framework for a convective parameterization.
Forcing of Tropical SST Anomalies by Wintertime AO-like Variability
Authors: Wu Qigang
Published: December 2009

A lagged maximum covariance analysis (MCA) is utilized to investigate large-scale patterns of covariability between sea surface temperature (SST) in the global tropics and 500-mb geopotential height (Z500) in the extratropics at monthly to interannual time scales distinct from the conventional El Niño–Southern Oscillation (ENSO) signal during the Northern Hemisphere (NH) winter. The first MCA mode indicates a strong impact of tropical SST anomalies associated with ENSO on the extratropical atmosphere. The second MCA mode corresponds with coupling between Arctic Oscillation (AO)-like atmospheric variations and tropical SST anomalies. An AO-like MCA mode appears to depict an atmosphere-to-ocean forcing, in which the tropical ocean responds to the higher extratropical AO-like atmospheric anomalies with an intraseasonal time lag. In winter, AO-like atmospheric variability is associated with the northern tropical Atlantic mode and the tropical Pacific ENSO Modoki mode through enhanced or weakened trade winds.

The above forced SST anomalies by the AO-like variability may play a role in the subsequent evolution of the conventional ENSO phenomena.