bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermodynamic modelling and simulation of advanced combined cycle for performance enhancement
Authors: Sanjay  , Singh O , Prasad B N
Published: September 2008

This paper deals with the development requirements of a gas—steam combined cycle power plant with the aim to achieve plant efficiency in excess of 62 per cent through various possibilities of performance enhancement in topping cycle and bottoming cycle. For this study, the reference-combined cycle configuration (MS9001 series) power plant of General Electric has been considered. The innovation possibilities include the increase in rotor/turbine inlet temperature; development of advanced high-temperature blade material with superior thermal barrier coatings; advanced inlet duct and compressor inlet design to minimize loss; improved individual component efficiencies; improved turbine blade cooling techniques; better blade cooling mediums; incorporating intercooling and reheat either separately or in combination with the simple gas turbine cycle using higher cycle pressure ratio; improved gas turbine exhaust heat utilization in the heat recovery steam generator, minimize stack gas temperature; as well as best shaft system configuration. This study quantifies each of these development possibilities and shows that on incorporating these factors in the reference cycle it could offer the combined cycle plant efficiency above 65 per cent.
Energy performance regression models for office buildings with daylighting controls
Authors: Li D H W , Wong S L , Cheung K L
Published: September 2008

Sensitivity analysis is performed to observe the response of the system when a given design parameter is changed. It is important to know the relationships between the input parameters and output results such that appropriate design variables can be selected to achieve the optimum building energy performance. This paper studies the sensitivity of energy performance and establishes regression models for office buildings with daylighting designs in Hong Kong. The building energy simulation computer program, namely EnergyPlus, was used to generate data for the analysis. The important input design parameters affecting the daylighting schemes were identified and analysed in terms of annual building electricity expenditures and peak electrical demands. Four building envelope design parameters, namely, window-to-wall ratio, light transmittance of windows, projection ratio of overhang, and projection ratio of side-fins were found to correlate well with the predicted incremental electricity use (IEU) and incremental peak electricity use (IPEU). Both linear and non-linear multiple regression techniques were used to develop regression models and energy equations for the predictions of IEU and IPEU. Statistical results show that such models and equations can be used to evaluate the energy performance of various building envelope design schemes for building with daylighting controls during the early design stage.
Axisymmetric design of axial turbomachines: An inverse method introducing profile losses
Authors: Rosa Taddei S , Larocca F
Published: September 2008

The distributed loss model has been included in a time-marching Euler solver. This predicts the axisymmetric flow field and hub-to-tip stream surface geometry once the loading distribution is prescribed in the blade regions. The loss model replaces shear stresses with a suitable viscous force distribution, which does not work on the relative flow motion, but is only meant to produce entropy along the meridional streamlines. As in a fully inverse computation the flow angles are unknown, empirical loss correlations for single cascades cannot be used. The overall loss level through each blade row will be provided by the one-dimensional stage of the design process, then simplifying assumptions or specific correlations are used to estimate its spanwise distribution. The loss model effects on the flow field and stream surface geometry predicted by the inverse solver have been assessed.
Antibacterial Quinone Metabolites from the Brown Alga, Sargassum sagamianum
Authors: Horie Shohei , Tsutsumi Shinsuke , Takada Yuuki , Kimura Junji
Published: September 2008

Antibacterial sargaquinoic acid derivatives were isolated from the brown alga Sargassum sagamianum. The structures of these quinone metabolites were confirmed by NMR and mass spectroscopy, and by comparison with published data. The relationship between their structures and antibacterial activities are briefly discussed.
Chemistry of Anthracene–Acetylene Oligomers. X. Synthesis, Structures, and Properties of 1,8-Anthrylene–Alkynylene Cyclic Trimers
Authors: Toyota Shinji , Miyahara Hiroaki , Goichi Michio , Wakamatsu Kan , Iwanaga Tetsuo
Published: September 2008

Two types of 1,8-anthrylene cyclic trimers with acetylene and diacetylene linkers were synthesized by macrocyclization of the acyclic precursors with Eglinton coupling as examples of the smallest analogues with an odd number of anthracene units. The X-ray analysis and DFT calculations revealed the nonplanar and strained cyclic structures of C2 and Cs symmetries for the compound with three diacetylene linkers and that with one diacetylene and two acetylene linkers, respectively, with significant bending deformations of acetylene carbons and anthracene moieties. The dynamic behavior of these cyclic compounds was analyzed by VT NMR measurements with the aid of DFT calculations. The NMR chemical shifts and the electronic spectra of the trimers are compared with those of the tetramers and dimers in terms of the orientation of anthracene units and the molecular strains.
Catalytic Nucleophilic Addition Reaction to (2-Furyl)carbene Intermediates Generated from Carbonyl–Ene–Ynes
Authors: Miki Koji , Kato Yumiko , Uemura Sakae , Ohe Kouichi
Published: September 2008

Rhodium- and chromium-catalyzed addition reactions of various σ-bonds, such as C–H, N–H, O–H, Si–H, and S–H bonds, to (2-furyl)carbenoids in situ generated from conjugated carbonyl–ene–yne compounds having electron-withdrawing groups on an alkyne terminus are described. 2-Alkoxy-2,5-dihydrofuran was obtained from the chromium-catalyzed addition reaction of an alcohol with the (2-furyl)carbene chromium intermediates in a conjugate manner.
On the geometry of Grassmannian equivalent connections
Authors: Manno Gianni
Published: September 2008

We study the geometry ofn-Grassmannian equivalent connections, that is linear connections without torsion admitting the same equation ofn-dimensional totally geodesic submanifolds. We introduce then-Grassmannian structure as a distinguished distribution on the Grassmann bundle, and then compute then-Grassmannian invariants, recovering forn= 1 the projective invariants of Thomas.
On Lie groups as quasi-Kähler manifolds with Killing Norden metric
Authors: Manev Mancho , Mekerov Dimitar
Published: September 2008

A 6-parametric family of 6-dimensional quasi-Kähler manifolds with Norden metric is constructed on a Lie group. This family is characterized geometrically.
Relating the curvature tensor and the complex Jacobi operator of an almost Hermitian manifold
Authors: Brozos-Vázquez M. , García-Río E. , Gilkey P.
Published: September 2008

Let J be a unitary almost complex structure on a Riemannian manifold (M, g). If x is a unit tangent vector, let π := Span{x, Jx} be the associated complex line in the tangent bundle of M. The complex Jacobi operator and the complex curvature operators are defined, respectively, by and . We show that if (M, g) is Hermitian or if (M, g) is nearly Kähler, then either the complex Jacobi operator or the complex curvature operator completely determine the full curvature operator; this generalizes a well known result in the real setting to the complex setting. We also show that this result fails for general almost Hermitian manifolds.
A characterization of m-ovoids and i-tight sets of polar spaces
Authors: De Bruyn Bart
Published: September 2008

Let P be a finite polar space of rank r ≥ 2 with q + 1 ≥ 3 points on each line. In [J. Bamberg, S. Kelly, M. Law, T. Penttila, Tight sets and m-ovoids of finite polar spaces. J. Combin. Theory Ser. A
114 (2007), 1293–1314. MR2353124] and [J. Bamberg, M. Law, T. Penttilla, Tight sets and m-ovoids of generalised quadrangles. Combinatorica, to appear.] it was shown that every m-ovoid of P intersects every i-tight set of P in precisely mi points. In the present paper, we characterize m-ovoids of P as those sets of points which have constant intersection size with each member of a “nice family” of i-tight sets of P and conversely, we characterize i-tight sets of P as those sets of points which have constant intersection size with each member of a “nice family” of m-ovoids. Some interesting corollaries of these characterization theorems are given.
Nonrational del Pezzo fibrations
Authors: Cheltsov Ivan
Published: September 2008

Let X be a general divisor in |3M + nL| on the rational scroll Proj where di
and n are integers, M is the tautological line bundle, L is a fibre of the natural projection to ℙ1, and d
1

d4
= 0. We prove that X is rational
d
1 = 0 and n = 1.
Sphingolipid management by an orchestra of lipid transfer proteins
Authors: Neumann Sylvia , van Meer Gerrit
Published: September 2008

The various membranes in eukaryotic cells have unique lipid compositions. Despite important discoveries in lipid research over recent decades, the basic principles by which cells define their membrane compositions are essentially unknown. Cells must sense the concentration of each lipid, integrate such signals and regulate the activity of their metabolic enzymes and transport routes to dynamically meet their needs in terms of membrane composition. Sphingolipids constitute a lipid category that is essential for eukaryotic life and appears to be key to differences in lipid composition. Here we discuss recent findings that assign an important role to lipid transfer proteins in the regulation of sphingolipid metabolism, organization and function.
Relevance of the amino acid conversions L144R (Zaragoza) and L159P (Zavalla) in the apolipoprotein A-I binding site for haptoglobin
Authors: Cigliano Luisa , D'Andrea Luca D. , Maresca Bernardetta , Serino Milena , Carlucci Alessandro , Salvatore Alfonso , Spagnuolo Maria Stefania , Scigliuolo Graziana , Pedone Carlo , Abrescia Paolo
Published: September 2008

The high-density lipoprotein apolipoprotein A-I (ApoA-I) stimulates the enzyme lecithin-cholesterol acyltransferase (LCAT) in the reverse cholesterol transport pathway. Two ApoA-I variants, Zaragoza (L144R) and Zavalla (L159P), are associated with low levels of HDL-cholesterol but normal LCAT activity. Haptoglobin interacts with ApoA-I, impairing LCAT stimulation. Synthetic peptides matching the haptoglobin-binding site of native or variant ApoA-I (native, P2a; variants, Zav-pep and Zar-pep) bound haptoglobin with different activity: Zar-pep>P2a>Zav-pep. They also differently rescued LCAT in vitro activity in the presence of haptoglobin (P2a=Zar-pep>Zav-pep). Therefore, both amino acid conversions affect haptoglobin binding and LCAT regulation. We highlight the role of haptoglobin in LCAT regulation in subjects with ApoA-I variants.
Immunohistochemical evidence of ubiquitous distribution of the metalloendoprotease insulin-degrading enzyme (IDE; insulysin) in human non-malignant tissues and tumor cell lines
Authors: Weirich Gregor , Mengele Karin , Yfanti Christina , Gkazepis Apostolos , Hellmann Daniela , Welk Anita , Giersig Cecylia , Kuo Wen-Liang , Rosner Marsha Rich , Tang Wei-Jen , Schmitt Manfred
Published: September 2008

Immunohistochemical evidence of ubiquitous distribution of the metalloprotease insulin-degrading enzyme (IDE; insulysin) in human non-malignant tissues and tumor cells is presented. Immunohistochemical staining was performed on a multi-organ tissue microarray (pancreas, lung, kidney, central/peripheral nervous system, liver, breast, placenta, myocardium, striated muscle, bone marrow, thymus, and spleen) and on a cell microarray of 31 tumor cell lines of different origin, as well as trophoblast cells and normal blood lymphocytes and granulocytes. IDE protein was expressed in all the tissues assessed and all the tumor cell lines except for Raji and HL-60. Trophoblast cells and granulocytes, but not normal lymphocytes, were also IDE-positive.
Regulation of kinin B2receptors by bradykinin in human lung cells
Authors: Bengtson Sara H. , Eddleston Jane , Mörgelin Matthias , Zuraw Bruce L. , Herwald Heiko
Published: September 2008

Bradykinin is a potent mediator of inflammation that has been shown to participate in allergic airway inflammation. The biologic effects of bradykinin are mediated by binding and activation of its cognate receptor, the B2receptor (B2R). In the lung fibroblast cell line IMR-90, binding of bradykinin to B2R triggers down-regulation of receptor surface expression, suggesting that bradykinin-induced inflammation is transient and self-limited. Notably, subjects with chronic airway inflammation continue to respond to BK following a first challenge. B2Rs are expressed on many different lung cell types, including airway epithelial cells. We therefore compared IMR-90 cells with the human lung epithelial cell line BEAS2B and found that B2R expression in the two cell types is differently regulated by BK. Whereas BK induces down-regulation of B2R in IMR-90 cells, the same treatment leads to up-regulation of the receptor in BEAS2B cells. These results provide a possible explanation for the potency of bradykinin in inducing ongoing airway inflammation.
Sphingosine kinase 1 and 2 regulate the capacity of mesangial cells to resist apoptotic stimuli in an opposing manner
Authors: Hofmann Lotte P. , Ren Shuyu , Schwalm Stephanie , Pfeilschifter Josef , Huwiler Andrea
Published: September 2008

Sphingosine kinases (SKs) are key enzymes regulating the production of sphingosine-1-phosphate (S1P), which determines important cell responses including cell growth and death. Here we show that renal mesangial cells isolated from wild-type, SK-1-/-, and SK-2-/- mice show a differential response to apoptotic stimuli. Wild-type mesangial cells responded to staurosporine with increased DNA fragmentation and caspase-3 processing, which was enhanced in SK-1-/- cells. In contrast, SK-2-/- cells were highly resistant to staurosporine-induced apoptosis. Furthermore, the basal phosphorylation and activity of the anti-apoptotic protein kinase B (PKB) and of its substrate Bad were decreased in SK-1-/- but not in SK-2-/- cells. Upon staurosporine treatment, phosphorylation of PKB and Bad decreased in wild-type and SK-1-/- cells, but remained high in SK-2-/- cells. In addition, the anti-apoptotic Bcl-XL was significantly upregulated in SK-2-/- cells, which may further contribute to the protective state of these cells. In summary, our data show that SK-1 and SK-2 have opposite effects on the capacity of mesangial cells to resist apoptotic stimuli. This is due to differential modulation of the PKB/Bad pathway and of Bcl-XL expression. Thus, subtype-selective targeting of SKs will be critical when considering these enzymes as therapeutic targets for the treatment of inflammation or cancer.
Molecular profile of breast versus ovarian cancer cells in response to treatment with the anticancer drugs cisplatin, carboplatin, doxorubicin, etoposide and taxol
Authors: Thomadaki Hellinida , Scorilas Andreas
Published: September 2008

We assessed changes in the apoptosis-related genes BCL2, BAX, BCL2L12, FAS and CASPASE-3 in OVCAR-3 human ovarian cancer cells and BT-20 human breast cancer cells to provide an insight into the molecular mechanisms involved in the response of these cells to treatment with anticancer drugs and to assess their value as potential biomarkers of chemotherapy response in breast and ovarian cancer. Cells were treated with different chemotherapeutic drugs (cisplatin, carboplatin, doxorubicin, etoposide and taxol) and assessed for changes in the expression of apoptosis-related genes at the mRNA level. Total RNA was extracted, reverse-transcribed into cDNA and amplified by PCR using gene-specific primers. GAPDH was used as a housekeeping gene. Cytotoxicity was assessed by MTT assay. Both cancer cell lines responded differentially at the molecular level to the drug treatments. OVCAR-3 cells showed more pronounced sensitivity and changes compared to BT-20 cells at the mRNA level for different apoptosis-related genes, leading to cell and cancer type dependence in conjunction with drug dependence.
Acid β-glucosidase: insights from structural analysis and relevance to Gaucher disease therapy
Authors: Kacher Yaacov , Brumshtein Boris , Boldin-Adamsky Swetlana , Toker Lilly , Shainskaya Alla , Silman Israel , Sussman Joel L. , Futerman Anthony H.
Published: September 2008

In mammalian cells, glucosylceramide (GlcCer), the simplest glycosphingolipid, is hydrolyzed by the lysosomal enzyme acid β-glucosidase (GlcCerase). In the human metabolic disorder Gaucher disease, GlcCerase activity is significantly decreased owing to one of approximately 200 mutations in the GlcCerase gene. The most common therapy for Gaucher disease is enzyme replacement therapy (ERT), in which patients are given intravenous injections of recombinant human GlcCerase; the Genzyme product Cerezyme® has been used clinically for more than 15 years and is administered to approximately 4000 patients worldwide. Here we review the crystal structure of Cerezyme® and other recombinant forms of GlcCerase, as well as of their complexes with covalent and non-covalent inhibitors. We also discuss the stability of Cerezyme®, which can be altered by modification of its N-glycan chains with possible implications for improved ERT in Gaucher disease.
Anaphoric pronominal reference in Russian and German narratives: bilingual and monolingual settings
Authors: Gagarina Natalia
Published: September 2008

The study compares the rate and type of the anaphoric pronominalisation in narratives produced by adults, by monolingual and by consecutive and simultaneous bilingual five-year-old children. In particular, it addresses the question which types of pronouns children use to refer to previously introduced antecedents and which syntactic role these antecedent NPs exhibit. Results show that consecutive bilinguals show a lower pronominalisation rate as compared to the narratives of monolingual German-speaking children and to their own Russian narratives. These findings are discussed within the construction-based model of language acquisition (Tomasello 2003). Language-specific organisation of the pronominal systems as well as the language-specific structural features are argued to have an impact on the pronominalisation rate in discourse.
Polycomb gene expression and histone H3 lysine 27 trimethylation changes during bovine preimplantation development
Authors: Ross Pablo J , Ragina Neli P , Rodriguez Ramon M , Iager Amy E , Siripattarapravat Kannika , Lopez-Corrales Nestor , Cibelli Jose B
Published: September 2008

Trimethylation of histone H3 at lysine 27 (H3K27me3) is established by polycomb group genes and is associated with stable and heritable gene silencing. The aim of this study was to characterize the expression of polycomb genes and the dynamics of H3K27me3 during bovine oocyte maturation and preimplantation development. Oocytes and in vitro-produced embryos were collected at different stages of development. Polycomb gene expression was analyzed by real-time quantitative RT-PCR and immunofluorescence. Global H3K27me3 levels were determined by semiquantitative immunofluorescence. Transcripts for EZH2, EED, and SUZ12 were detected at all stages analyzed, with EZH2 levels being the highest of the three at early stages of development. By the time the embryo reached the blastocyst stage, the level of PcG gene mRNA levels significantly increased. Immunofluorescence staining indicated nuclear expression of EZH2 at all stages while nuclear localized EED and SUZ12 were only evident at the morula and blastocyst stages. Semiquantitative analysis of H3K27me3 levels showed that nuclear fluorescence intensity was the highest in immature oocytes, which steadily decreased after fertilization to reach a nadir at the eight-cell stage, and then increased at the blastocyst stage. These results suggest that the absence of polycomb repressive complex 2 proteins localized to the nucleus of early embryos could be responsible for the gradual decrease in H3K27me3 during early preimplantation development.
Peptidase activities in Crotalus durissus terrificus semen
Authors: Marinho Camila Eduardo , Almeida-Santos Selma Maria , Carneiro Sylvia Mendes , Yamasaki Simone Cristina , Silveira Paulo Flavio
Published: September 2008

To understand the role of peptidases in seminal physiology of Crotalus durissus terrificus, activity levels of representative enzymes in semen and their sensitivities to inhibitors, cofactors, and peptide hormones were evaluated. The existence of seminal fractions and the association of peptidases with these fractions were also characterized for the first time in snakes. The prominent inhibitors of aminopeptidases (APs) were amastatin for acid, basic, and neutral; bestatin for basic; and diprotin A for dipeptidyl-IV. Cystyl and prolyl-imino APs were similarly susceptible to the majority of these inhibitors. The basic and neutral were characterized as metallo-peptidases, acid AP was activated by MnCl2, and cystyl, prolyl-imino, and type I pyroglutamyl were characterized as sulphydryl-dependent APs. Angiotensin II, vasotocin, bradykinin, fertilization-promoting peptide, and TRH altered the majority of these peptidase activities; these peptides are possible substrates and/or modulators of these peptidases. Peptidase activities were found in all seminal fractions: seminal plasma (SP), prostasome-like (PR) structures, and soluble (S-) and membrane-bound fractions (MFs) of spermatozoa. The levels of activity of each peptidase varied among different seminal fractions. In SP, the higher activities were puromycin-insensitive neutral and basic APs. In PR, the higher activity was puromycin-insensitive neutral AP. In spermatozoa, the higher activity in subcellular SF was puromycin-sensitive neutral, while in MF both puromycin-sensitive and -insensitive neutral APs were equally higher than the other examined peptidases. Data suggested that these peptidases, mainly basic and neutral, have a high relevance in regulating seminal functions of C. d. terrificus.
Chromosomal Regions Underlying Noncoagulation of Milk in Finnish Ayrshire Cows
Authors: Tyrisevä Anna-Maria , Elo Kari , Kuusipuro Arja , Vilva Veijo , Jänönen Isto , Karjalainen Heidi , Ikonen Tiina , Ojala Matti
Published: September 2008

About 10% of Finnish Ayrshire cows produce noncoagulating milk, i.e., milk that does not form a curd in a standard 30-min testing time and is thus a poor raw material for cheese dairies. This phenomenon is associated with peak and midlactation, but some cows produce noncoagulating milk persistently. A genomewide scan under a selective DNA pooling method was carried out to locate genomic regions associated with the noncoagulation of milk. On the basis of the hypothesis of the same historical mutation, we pooled the data across sires. Before testing pools for homogeneity, allele intensities were corrected for PCR artifacts, i.e., shadow bands and differential amplification. Results indicating association were verified using daughter design and selective genotyping within families. Data consisted of 18 sire families with 477 genotyped daughters in total, i.e., 12% of each tail of the milk coagulation ability. Data were analyzed using interval mapping under maximum-likelihood and nonparametric methods. BMS1126 on chromosome 2 and BMS1355 on chromosome 18 were associated with noncoagulation of milk across families on an experimentwise 0.1% significance level. By scanning gene databases, we found two potential candidate genes: LOC538897, a nonspecific serine/threonine kinase on chromosome 2, and SIAT4B, a sialyltransferase catalyzing the last step of glycosylation of κ-casein on chromosome 18. Further studies to determine the role of the candidates in the noncoagulation of milk are clearly needed.
On the Detection of Imprinted Quantitative Trait Loci in Line Crosses: Effect of Linkage Disequilibrium
Authors: Sandor Cynthia , Georges Michel
Published: September 2008

Imprinted quantitative trait loci (QTL) are commonly reported in studies using line-cross designs, especially in livestock species. It was previously shown that such parent-of-origin effects might result from the nonfixation of QTL alleles in one or both parental lines, rather than from genuine molecular parental imprinting. We herein demonstrate that if linkage disequilibrium exists between marker loci and nonfixed QTL, spurious detection of pseudo-imprinting is increased by an additional 40–80% in scenarios mimicking typical livestock situations. This is due to the fact that imprinting can be tested only in F2 offspring whose sire and dam have distinct marker genotypes. In the case of linkage disequilibrium between markers and QTL, such parents have a higher chance to have distinct QTL genotypes as well, thus resulting in distinct padumnal and madumnal allele substitution effects, i.e., QTL pseudo-imprinting.
A Fundamental Relationship Between Genotype Frequencies and Fitnesses
Authors: Lachance Joseph
Published: September 2008

The set of possible postselection genotype frequencies in an infinite, randomly mating population is found. Geometric mean heterozygote frequency divided by geometric mean homozygote frequency equals two times the geometric mean heterozygote fitness divided by geometric mean homozygote fitness. The ratio of genotype frequencies provides a measure of genetic variation that is independent of allele frequencies. When this ratio does not equal two, either selection or population structure is present. Within-population HapMap data show population-specific patterns, while pooled data show an excess of homozygotes.
FDA Report: Eculizumab (Soliris®) for the Treatment of Patients with Paroxysmal Nocturnal Hemoglobinuria
Authors: Dmytrijuk Andrew , Robie-Suh Kathy , Cohen Martin H. , Rieves Dwaine , Weiss Karen , Pazdur Richard
Published: September 2008

Learning Objectives

After completing this course, the reader will be able to: Describe the mechanism of action of eculizumab in PNH.Discuss the efficacy findings upon which the approval of eculizumab was based.Manage the safety concerns surrounding the use of eculizumab for the treatment of patients with PNH.Discuss the efficacy and side effect profile of eculizumab.

CME This article is available for continuing medical education credit at CME.TheOncologist.com

On March 16, 2007, eculizumab (Soliris®; Alexion Pharmaceuticals, Inc. Cheshire, CT), a humanized monoclonal antibody that binds to the human C5 complement protein, received accelerated approval by the U.S. Food and Drug Administration for the treatment of patients with paroxysmal nocturnal hemoglobinuria (PNH) to reduce hemolysis. Eculizumab was studied in a randomized, double-blind, placebo-controlled clinical trial in 87 RBC transfusion–dependent adult PNH patients and in a supportive single-arm study in 96 patients. The eculizumab dose was 600 mg as a 35-minute i.v. infusion administered weekly for the first 4 weeks followed by 900 mg (week 5) then 900 mg every 14 days thereafter. Hemoglobin stabilized in 21 of 43 (48.8%) eculizumab-treated patients, compared with none of 44 placebo-treated patients. Eculizumab-treated patients required significantly fewer RBC transfusions than placebo-treated patients (median, 0 versus 10 units). There was also a significant reduction in the serum lactate dehydrogenase area under the curve with eculizumab compared with placebo treatment. Results of the phase II supportive study were similar to those of the phase III study. The safety database included 196 adult patients with PNH. Significant findings included the development of human anti-human antibody responses in three patients and serious meningococcal infections in three patients. Patients should undergo meningococcal vaccination at least 2 weeks prior to receiving the first eculizumab treatment and have revaccination according to current medical guidelines. Patients must be monitored and evaluated immediately for early signs of meningococcal infections and treated with antibiotics as indicated.
Effect of sex steroids on plasma C-type natriuretic peptide forms: stimulation by oestradiol in lambs and adult sheep
Authors: Prickett Timothy C R , Barrell Graham K , Wellby Martin , Yandle Timothy G , Richards A Mark , Espiner Eric A
Published: September 2008

Although C-type natriuretic peptide (CNP) is crucial to post-natal endochondral growth, roles for the hormone in pubertal bone growth and the physiological effects of sex steroid substitution on CNP synthesis are not known. Using a plasma marker of CNP tissue synthesis (amino-terminal proCNP, NTproCNP), we have studied the effect of exogenous oestrogen (E2) or testosterone (T) on plasma CNP forms and bone alkaline phosphatase (bALP) in pre-pubertal lambs. Responses to E2 in non-cycling adult ewes were also studied. In 15-week-old intact ewe lambs, E2 promptly increased plasma NTproCNP and CNP (P<0.001) to peak on day 2, and bALP (P<0.001 peaking on day 7), whereas no significant stimulation in response to T was observed in male lambs. Linear bone growth and live weight were unaffected. In adult anoestrous ewes, basal concentrations of CNP forms and bALP were lower than in ewe lambs, in keeping with skeletal maturity, but adults responded similarly to E2. Prompt and sustained increases in NTproCNP and CNP, and a later threefold rise in bALP (all P<0.001), were induced by E2. Possible contributions to these increases in plasma CNP forms by reproductive tissues (a known site of E2-induced CNP expression) were excluded by showing similar E2-induced CNP responses in adult ewes after surgical removal of reproductive tissues. These results are the first to show that E2 stimulates plasma CNP forms and bALP in lambs and adult sheep and raise the possibility that CNP also participates in bone formation in the mature skeleton.
Computer modelling of graded sediments in rivers
Authors: Shvidchenko A. B. , Pender G.
Published: September 2008

This paper reports on current engineering capability to simulate the behaviour of graded sediments in rivers using one-dimensional computer models. Emphasis is placed on non-equilibrium conditions when the bedload transport rate, bed elevation and composition of the bed material are changing with time. The model used is typical of those available to practicing engineers. A general description is given and comparisons are made of the model's ability to reproduce available laboratory and field data. The performance of four sediment transport equations (Ackers and White, Meyer-Peter and Muller, White and Day, Parker) in predicting graded sediment movement is assessed by comparison with the measured data. Of these equations, the first two were originally developed for application to uniform sediment and do not account for size fraction interaction, while the other two take account of sediment grading. The test simulations demonstrate that the use of the Parker equation provides the best overall agreement with the measured data, while the use of the other equations provides inadequate prediction in the case of graded sediments. It is concluded that an adequate computer simulation of long-term trends in the behaviour of graded sediments is only possible if size fraction interaction in the sediment mixtures is accounted for in the sediment transport equation used.
TOF-FS: a technique for detection and monitoring of wall loss defects in large areas of vessels and pipework
Authors: Terpstra S , Hoeve F , McCann Z , Stone M
Published: September 2008

The Oil and Gas industry has an increasing need to inspect large areas of vessels and pipework for internal corrosion damage. Traditionally this can be done during plant shutdowns, when it is possible to gain entry to the inside of a vessel, to check for damage visually. However, there
are safety and economic benefits if the inspection can be carried out non-intrusively, from the external surface of the vessel or pipework, without taking the plant off-line. In developing a non-intrusive inspection plan, it can be demanding to satisfy the requirements of a modern, risk-based
inspection (RBI) approach. Firstly, reliable detection has to be achieved, even when damage is localised. This may require near-100% inspection coverage, particularly when the location of the corrosion damage cannot reliably be predicted. In such cases, fast scanning techniques are required,
to ensure that large areas can be covered economically. Secondly, when damage is present, accurate measurement of its depth is required in order to obtain an accurate estimate of the corrosion rate; the latter contributes significantly to the optimisation of inspection intervals.The Time-of-Flight
Fast Screening (TOF-FS) technique was developed to meet these requirements. Its principles are explained, including the use of the compression and mode-conversion signals to enlarge the detection footprint and thus the scanning speed. For analysis and processing of the vast amounts of data
collected during a TOF-FS inspection, a software tool is described, which was developed to automate the conversion of arrival time into depth and into an easy-to-read corrosion map. Another software tool has been developed to support the optimisation of the probe parameters. Developments in
scanning tools have resulted in fast and flexible scanning, even in the presence of natural obstructions like nozzles, attachments, etc. This work is illustrated with inspection results obtained in various operating environments.
Acoustic emissions from oil lubricated metal on metal sliding contacts
Authors: Wang L , Wood R , Sun J
Published: September 2008

This study investigates the condition monitoring of oil lubricated metal on metal sliding contacts using various sensing techniques including acoustic emissions. The worn surfaces are examined and wear mechanisms are explored and linked with the on-line sensor signals. This study tackles
the condition monitoring problems from the tribological point of view, ie at a micro-scale. Experimental work was carried out on a ball-on-disc tribometer using an En31 bearing steel ball and disc lubricated by a mineral base oil, Shell Vitrea 460. The base oil was used to eliminate the formation
of possible additive films and to promote the onset of scuffing. The sliding speed was kept at 6 m/s under maximum Hertzian contact pressures of 3 GPa. An oil starvation strategy was also applied to promote adhesive failure. The tests generated multiple contact wear mechanisms and enabled
correlations between AE signals and wear mechanisms to be identified. Tests were stopped at various stages to enable surface examination using scanning electron microscopy (SEM). The results show that AE gives an early indication of adhesive wear of the lubricated metal contacts using r.m.s
signals. Snapshots of AE waveforms also show that burst signals changed to continuous signals when the contact changed from fully lubricated to starved conditions. AE energy shifts within the broad frequency band of 300 kHz and 1 MHz give early indications of scuffing.
Condition monitoring of exhaust system blowers using infrared thermography
Authors: Bagavathiappan S , Saravanan T , George N P , Philip John , Jayakumar T , Raj Baldev
Published: September 2008

Electrical and mechanical machines are integral parts of engineering plants. Machine failures can occur due to many reasons. Thermal energy produced during the operation of all machines can be in the form of friction losses within machines, energy losses within machines, as a characteristic of the process media, or any combination thereof. Infrared thermography (IRT) is an ideal Non-Destructive Testing (NDT) technique to investigate abnormal temperature distribution on machine surfaces, because it provides thermal images of a machine or component remotely. In this paper, we discuss an important application of thermal imaging for condition monitoring of blower bearings, shaft and the motors in ventilation systems used in nuclear plant areas. Sources of abnormal temperatures are detected at the bearings and shaft at the impeller end of the blower of an exhaust system. Also, abnormal temperature distribution is detected in one of the belts of the pulley drive system due to over-tightening. IRT was effectively utilised to pinpoint the sources of excessive heat in the blower and to carry out necessary corrections. We demonstrate the usefulness of IRT to detect the sources of abnormal temperatures in various components of the blower at an early stage of impending malfunction failure that could prevent major breakdowns.
Medical Accuracy in Sexuality Education: Ideology and the Scientific Process
Authors: Santelli John S.
Published: September 2008

Recently, many states have implemented requirements for scientific or medical accuracy in sexuality education and HIV prevention programs. Although seemingly uncontroversial, these requirements respond to the increasing injection of ideology into sexuality education, as represented by abstinence-only programs.

I describe the process by which health professionals and government advisory groups within the United States reach scientific consensus and review the legal requirements and definitions for medical accuracy. Key elements of this scientific process include the weight of scientific evidence, the importance of scientific theory, peer review, and recognition by mainstream scientific and health organizations. I propose a concise definition of medical accuracy that may be useful to policymakers, health educators, and other health practitioners.
Mechanistic Understanding of Rock/Phosphonate Interactions and the Effect of Metal Ions on Inhibitor Retention
Authors: Tomson Mason B. , Kan Amy T. , Fu Gongmin , Shen Dong , Nasr-El-Din Hisham A. , Al-Saiari Hamad , Al-Thubaiti Musaed
Published: September 2008

This paper discusses the effects of Ca2+, Mg2+, and Fe2+ on inhibitor retention and release. Better understanding of phosphonate reactions during inhibitor squeeze treatments has direct implication on how to design and improve scale inhibitor squeeze treatments for optimum scale control. Putting various amounts of metal ions in the inhibitor pill adds another degree of freedom in squeeze design, especially in controlling return concentrations and squeeze life.

Phosphonate reactions during squeeze treatments involve a series of self-regulating reactions with calcite and other minerals. However, excess calcite does not improve the retention of phosphonate due to the surface poisoning effect of Ca2+. The squeeze can be designed so that maximum squeeze life is achieved by forming a low solubility phase in the formation. Addition of Ca2+, Mg2+, and Fe2+ in the pill solution at 0.1 to 1 molar ratios significantly improves the retention of phosphonate. Alternatively, these metal ions can be dissolved from the formation while an acidic inhibitor pill is in contact with the formation minerals. Both BHPMP and DTPMP returns were significantly extended by the addition of metal ions (e.g., Ca2+ and Fe2+). The addition of Mg2+ may increase the long-term return concentration, which is important for some wells where a higher inhibitor return concentration is needed.

The laboratory squeeze simulations were compared to return data obtained from squeeze treatments performed on two wells located in a sandstone reservoir in Saudi Arabia. The sandstone formation contains significant amounts of iron-bearing minerals.
Data Analysis of Barnett Shale Completions
Authors: Shelley Bob , Grieser Bill , Johnson Bill J. , Fielder Eugene O. , Heinze James R. , Werline J. R.
Published: September 2008

The north Texas Barnett shale illustrates the successful commercialization of an unconventional reservoir. However, it took 17 years to evolve from pumping crosslinked gel (XLG) carrying more than 1 million lbm of proppant per job to sand waterfracs (SWFs) consisting of large volumes of water with friction reducer and small quantities of sand. This transition to SWF stimulation opened the door for widespread development that has advanced the Newark East (Barnett shale) to the largest producing gas field in Texas.

This paper investigates Barnett completion strategy from 1993 to 2002. The 393-well data set includes completion, reservoir, and production data. Unique data-evaluation tools and techniques were used to investigate various completion and reservoir parameters to determine their effects on production (Shelley and Stephenson 2000; Zangl and Hannerer 2003).

We found that production results show a broad scattering when crossplotted with various completion and reservoir inputs. This result is not uncommon when analyzing field data. However, general trends were identified through comparisons of large numbers of wells. These trends were confirmed through the use of more-advanced data-mining techniques, which included self-organizing mapping (SOM) of data. The results show that SWF-type stimulation of the Barnett outperformed to varying degrees XLG treatments for the five reservoir types used in this evaluation.
Experimental Investigation and Modeling of the Effects of Rising Gas Bubbles in a Closed Pipe
Authors: Al-Darmaki S. , Falcone G. , Hale C. P. , Hewitt G. F.
Published: September 2008

Transient multiphase flow in the wellbore causes problems in well-test interpretation when the well is shut in at surface and the pressure is measured downhole. Pressure-buildup data recorded during a test can be dominated by transient wellbore effects (i.e., phase change, flow reversal, and re-entry of the denser phase into the producing zone), making it difficult to distinguish between true reservoir features and transient wellbore artifacts (Gringarten et al. 2000).

This paper is a follow-up to paper SPE 96587 (Ali et al. 2005), which presented experimental results of phase redistribution effects on pressure-buildup data. Though the results of the experiments were revealing, they are complex because they reflect the real well situation. To obtain results in which the phase redistribution in the well is studied independently of the interaction with the reservoir, a further set of experiments was carried out. In these experiments, the tube (simulating the well) was isolated at both the top and the bottom at the same time. The pressure distribution was measured during the transient following shut-in and for the steady-state final condition, in which there was a liquid-filled zone at the bottom of the test section and a gas-filled zone at the top. A substantial number of tests were conducted in the bubbly-flow region and could therefore be analyzed by a simple 1D model for bubbly flow. The results of the comparison between the model and the experimental data are presented in this paper.
Gelation Kinetics and Performance Evaluation of an Organically Crosslinked Gel at High Temperature and Pressure
Authors: Al-Muntasheri G. A. , Nasr-El-Din H. A. , Zitha P. L. J.
Published: September 2008

Organically crosslinked gels have been used to control water production in high temperature applications. These chemical systems are based on the crosslinking of a polyacrylamide-based polymer/copolymer with an organic crosslinker. Polyethyleneimine (PEI) has been used as an organic crosslinker for polyacrylamide-based copolymers to provide thermally stable gels.

Literature reported that PEI can form aqueous gels with polyacrylamide (PAM) at room temperature. In this paper, we show for the first time the possibility of crosslinking polyacrylamide with PEI at temperatures up to 140°C (285°F) and pressures up to 30 bars (435 psi). This paper reports data both in bulk and in porous media.

The gelation time of the PAM crosslinked with PEI at high temperatures up to 140°C (285°F) and pressures up to 435 psi (30 bars) was measured. The effects of polymer concentration, crosslinker concentration, temperature, salinity, initial pH value, and the initial degree of hydrolysis of the polymer on the gelation time were examined in detail. All measurements were conducted in the steady shear mode. 13C Nuclear Magnetic Resonance Spectroscopy (13C NMR) was used to relate the gelation time to changes in the structure of the polymer and hence explain the variation in the gelation time in terms of the gelling system chemistry.

In bulk, thermally stable gels were obtained by crosslinking PAM with PEI at 130°C (266°F) for at least 8 weeks. The performance of the PAM/PEI system in sandstone cores at a temperature of 90°C (194°F) and pressure drops of 68.95 bars (1,000 psi) was examined. The system was found to be stable for 3 weeks, where the permeability was reduced by a factor of 100%.
Rainfed Wheat and Soybean Productivity in a Long‐Term Tillage Experiment in Central Italy
Authors: Mazzoncini Marco , Di Bene Claudia , Coli Antonio , Antichi Daniele , Petri Monica , Bonari Enrico
Published: September 2008

Tillage plays a key role in cropping system sustainability due to its impact on soil properties, crop yields, economic returns, labor, and energy requirements. The objective of our research was to compare the effects of no‐tillage (NT) and conventional tillage (CT) on durum wheat (Triticum durumDesf.) and soybean [Glycine max(L.) Merr.] productivity in a long‐term, 2‐yr rotation field experiment initiated in 1986 under a Mediterranean climate. The 16‐yr (1990–2005) average grain yield for NT wheat was 8.9% lower than that for CT wheat (3.97 vs. 4.36 Mg ha−1). Differences between tillage systems were significant in 6 out of the 16 seasons and were small when planting was early, weed control was good, and rainfall deficit occurred during the grain filling period. The 16‐yr average grain yield for soybean was significantly lower under NT than under CT (2.60 vs. 3.08 Mg ha−1) but differences between tillage systems were small and not significant in 12 out of the 16 seasons. In comparison to wheat, NT soybean had higher weed pressure. Nitrogen concentrations in wheat and soybean were little affected by tillage. Phosphorus concentrations in wheat grain and straw were generally higher under NT, while differences in soybean tissue P due to tillage were negligible.
Intercropping Spring Wheat with Cereal Grains, Legumes, and Oilseeds Fails to Improve Productivity under Organic Management
Authors: Pridham Jacqueline C. , Entz Martin H.
Published: September 2008

The success of organic wheat (Triticum aestivum L.) production can be severely inhibited by weed and disease pressures. This study sought to determine the effectiveness of wheat intercrop mixtures in suppressing weeds and diseases and increasing grain yield and net return. Field experiments were conducted on organically managed land in 2004 and 2005 and three representative intercrop systems were tested: wheat with other cereals [oats (Avena sativa L.), barley (Hordeum vulgare L.), and spring rye (Secale cereale L.)]; wheat and noncereal seed crops (flax [Linum usitatissimum L.], field pea [Pisum sativum L.], oriental mustard [Brassica juncea L.]); and wheat and cover crops (red clover [Trifolium pratense L.], hairy vetch [Vicia villosa L.], annual ryegrass [Lolium multiflorum Lam.]). The cereal intercrop systems provided no consistent yield benefit over wheat monocultures. Results from noncereal‐wheat intercrops were variable. Wheat‐flax reduced the wheat crop to unacceptable levels but was capable of reducing wheat flag leaf disease levels. Wheat‐field pea resulted in the lowest disease levels, yet had inconsistent yields, and more weeds than wheat monoculture. Wheat‐mustard did not reduce weeds or diseases, but it was capable of high grain yields and net returns, though usually hampered by flea beetle (Phyllotreta cruciferae) attack. The effect of cover crops on wheat was affected by environment. Wheat‐red clover and wheat‐hairy vetch did demonstrate the ability to maintain high wheat grain yield in certain site‐years. In conclusion, wheat intercrop mixtures provided little short‐term benefit over monoculture wheat in this study.