bluuebunny/crossref_metadata_2025 huggingface dataset:
15 The Accumulation of International Reserves as a Defense Strategy
Authors: Cardim de Carvalho Fernando J.
Published: February 2010

The chapter by Carvalho explores the accumulation of international reserves as a defensive strategy, as well as the reasons and limitations of their “self‐insurance” function. Conceptually, countries demand reserves of foreign currencies for a similar set of reasons to those which explain why individuals demand liquidity. However, while individuals hold liquid assets primarily to effect transactions, countries do it mostly for precautionary reasons. Again, as in the case of individuals, the stronger the demand for money, the harder it is to obtain liquidity in public sources and money markets. The chapter notes that international liquidity provision remains as important now as it was in the recent past. Carvalho argues that the best alternative would clearly be an international monetary system where a new international currency could be created according to global liquidity needs, as well as for emergency liquidity facilities to protect countries from adverse temporary external shocks.
17 A Modest Proposal for International Monetary Reform1
Authors: Greenwald Bruce , Stiglitz Joseph E.
Published: February 2010

Greenwald and Stiglitz argue that an ideal system of international payments should be characterized by stability and balance: stability in exchange rates and the absence of sudden crises, and balance in the sense that individual national economies should suffer neither from deflationary effects of chronic external deficits nor the distorting consequences of chronic external surpluses. Both requirements are essential to the efficient international movement of goods and resources. Yet neither requirement appears to have been met by the current dollar‐based reserve currency system. Recurrent crises in Asia, Latin America, and Eastern Europe, and chronic and growing U.S. payments deficits (with their associated deflationary impact) are longstanding characteristics of the current system.
2 Dissecting Matter
Authors: Giudice Gian Francesco
Published: February 2010

This chapter recounts the historical process that led to the understanding that matter is not a continuous substance, but comes in lumps. The philosophical concept of atoms, postulated by the Greek philosopher Democritus, entered science with the study of chemical reactions and properties of gases. But the first direct evidence for a corpuscular structure of matter came with the discovery of the electron by J. J. Thomson. The next step was Rutherford's discovery of the atomic nucleus, followed by the understanding that the nucleus is made of protons and neutrons. The exploration of the subatomic world led to the development of quantum mechanics, a theory which revolutionized our interpretation of physical reality. The chapter describes also the discovery and the meaning of antimatter.
5 Stairway to Heaven
Authors: Giudice Gian Francesco
Published: February 2010

This chapter discusses the reasons why fundamental physics needs to explore the world at small distances. Modern research has discovered that the physical laws of nature become progressively simpler at small scales and that, at every step, apparently unrelated phenomena actually become unified into single concepts. This recursive formulation of natural phenomena in terms of ever simpler elements is called in this book ‘Jacob's ladder’. It is then explained why particle accelerators and colliders are needed for the investigation of the fundamental laws of nature. Finally, the chapter presents the applications and achievements of accelerators and detectors outside the field of particle physics.
6 The Lord of the Rings
Authors: Giudice Gian Francesco
Published: February 2010

This chapter is devoted to the LHC accelerator complex. It first presents the history of the construction of the LHC and the challenges involved. It then describes the functioning of the LHC, following the path made by the beams of protons. The cutting-edge technologies developed for the LHC are explained using simple analogies. Applications outside particle physics of these technologies are also discussed. The different components of the LHC are described, with special emphasis on the superconducting dipole magnets, which are used to steer the proton beams inside the underground tunnel.
7 Telescopes Aimed at Zeptospace
Authors: Giudice Gian Francesco
Published: February 2010

The detectors are the instruments used to register the particles produced in the proton collisions and to reconstruct their tracks. This chapter describes the two main detectors employed at the LHC: ATLAS and CMS. The four main components common to both detectors are the trackers, the electromagnetic calorimeters, the hadron calorimeters, and the muon chambers. Both the ATLAS and the CMS detectors are built around powerful magnets that are needed to bend the trajectories of the charged particles produced in the collisions. This chapter also describes the trigger, which is the electronic system for identifying potentially interesting collisions events that are retained for offline analysis. The other experiments at the LHC are shortly presented. The chapter concludes with some observations on the human aspects of scientific international collaborations.
8 Breaking Symmetries
Authors: Giudice Gian Francesco
Published: February 2010

Symmetries play a fundamental role in modern physics. This chapter introduces this concept by discussing the meaning of symmetries in mathematics and in physics, explaining the significance of Lie groups. With the help of some analogies, the principle of gauge symmetry is illustrated. This principle is the basis for the construction of the Standard Model and determines the structure of the fundamental forces. However, the masses of the W and Z particles are in conflict with the gauge principle. The solution to this problem requires the introduction of new concepts such as spontaneous symmetry breaking and the Higgs mechanism. The chapter also describes the experimental strategies in the search for the Higgs boson, the significance of the possible discovery of this particle, and the remaining open problems.
10 Supersymmetry
Authors: Giudice Gian Francesco
Published: February 2010

Superspace is an extension of space-time which includes new coordinates with unusual algebraic rules. The nature of superspace is quantum mechanical, because it requires the concept of particle spin. This chapter describes the meaning of superspace and supersymmetry, and shows how these ideas can provide a solution to the naturalness problem. The impact of supersymmetry in the quest for unification is also discussed, from its role in superstring theory to the result of gauge coupling unification. Finally, the chapter describes how experiments at the LHC could discover supersymmetry.
Systematic review: prognostic tests of paracetamol‐induced acute liver failure
Authors: CRAIG D. G. N. , FORD A. C. , HAYES P. C. , SIMPSON K. J.
Published: February 2010

Aliment Pharmacol Ther 31, 1064–1076

Background  Paracetamol (acetaminophen) toxicity remains the leading cause of acute liver failure (ALF) in the developed world. In the UK, the recently modified King’s College Criteria are used to list patients for emergency liver transplantation, but these criteria have been criticized for their low sensitivity and for spectrum bias in their application.

Aim  To evaluate existing prognostic criteria critically for predicting death without transplantation in paracetamol‐induced ALF.

Methods  MEDLINE, EMBASE and CINAHL were searched to identify studies containing adult patients with paracetamol‐induced ALF. Selected studies were evaluated and data were pooled if appropriate, to calculate sensitivity, specificity and diagnostic odds ratios (DORs) of applied prognostic tests.

Results  Of 6507 studies identified, 14 were eligible for inclusion, evaluating 1960 patients. The original King’s College Criteria had a pooled sensitivity of 58.2% and specificity of 94.6%, with a DOR of 27.7. Addition of arterial lactate to the King’s College Criteria reduced the DOR to 26.1. Several other clinical and laboratory variables had higher DORs than the King’s College Criteria, but were only evaluated in single studies of limited quality.

Conclusions  The original King’s College Criteria remain well‐validated criteria with high prognostic accuracy. Other potential prognostic variables should be prospectively assessed in multicentre studies to refine the criteria further.
Eltrombopag does not affect cardiac repolarization: results from a definitive QTc study in healthy subjects
Authors: Matthys Gemma , Park Jung Wook , McGuire Sandra , Wire Mary Beth , Zhang Jianping , Bowen Carolyn , Williams Daphne , Jenkins Julian M. , Peng Bin
Published: February 2010

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

Some non‐anti‐arrhythmic drugs delay cardiac repolarization, which can be measured as an increase in the QT interval. Delays in cardiac repolarization create an electrophysiological environment that favours the development of cardiac arrhythmias, which may lead to torsade de pointes, which can be fatal. As part of the clinical development of eltrombopag, a thorough QTc study was conducted to evaluate the effects of eltrombopag on cardiac repolarization at both therapeutic and supratherapeutic doses and to characterize the relationship between plasma eltrombopag concentrations and change in QTc.

WHAT THIS STUDY ADDS

This study found no clinically significant QT prolongation for eltrombopag when administered as 50 mg or 150 mg every day for 5 days. There were no safety or tolerability signals of clinical concern. A small incidence of ventricular premature beats was observed, but this was consistent with previously reported incidences in healthy volunteers without apparent heart disease.

AIM

To evaluate the effect of eltrombopag on cardiac repolarization and to characterize the relationship between plasma eltrombopag concentrations and change in QTc.

METHODS

This was a double‐blind, placebo‐ and active‐controlled, randomized, balanced four‐period, crossover study in healthy men and women. Subjects were randomized to receive eltrombopag 50 mg and 150 mg, moxifloxacin 400 mg (positive control) and placebo in one of four sequences.

RESULTS

Eighty‐seven subjects entered the study and 48 completed. There was no prolongation of QTc (Fridericia) following eltrombopag treatment, as the upper limit of the 90% confidence interval (CI) for the time‐matched change from baseline in QTcF between drug and placebo (ddQTcF) did not exceed 10 ms for eltrombopag at either dose. Maximum observed mean treatment difference was 2.29 ms (90% CI 0.34, 4.24) for eltrombopag 150 mg at 1 h post‐dose and 11.64 ms (90% CI 9.64, 13.64) for moxifloxacin 400 mg at 4 h. Eltrombopag Cmax and AUC(0,24 h) increased in a dose proportional manner between 50 mg and 150 mg after 5 days' dosing. Proportions of subjects with adverse events were similar across treatments (52–66% of subjects). Most withdrawals (26/39 subjects) were due to elevated platelets. Three subjects were withdrawn for ventricular premature beats (one following each active treatment) reported as related to the study drug.

CONCLUSIONS

No clinically significant QTc prolongation was observed for eltrombopag at therapeutic and supratherapeutic doses.
Applying the double knock technique to control Conyza bonariensis
Authors: WERTH JEFF , WALKER STEVE , BOUCHER LUKE , ROBINSON GEOFF
Published: February 2010

Sequential applications of glyphosate followed by another postemergent herbicide, known as the “double knock” technique, were trialled for their effectiveness in controlling Conyza bonariensis. Combinations of glyphosate with and without 2,4‐D followed by paraquat plus diquat, paraquat, or 2,4‐D were tested at a range of follow‐up application times in two field and two pot experiments. The results showed that paraquat plus diquat or paraquat following glyphosate or glyphosate plus 2,4‐D provided highly effective weed control compared to glyphosate alone. The optimum timing for follow‐up applications of paraquat or paraquat plus diquat was between 5 and 7 days after the initial glyphosate application. Combined applications of glyphosate and 2,4‐D, compared to split applications, were not significantly different. However, following glyphosate application with 2,4‐D >1 day later considerably reduced the level of control. This study showed that the double knock technique is highly effective in controlling C. bonariensis and is rapidly becoming an important tool in the management of this problem weed.
Allelopathic effect of itchgrass (Rottboellia cochinchinensis) on seed germination and plant growth
Authors: MEKSAWAT SUNYATA , PORNPROM TOSAPON
Published: February 2010

Herbicides produce a wide range of toxic side‐effects that pose a potential hazard to the environment. The development of natural allelochemicals is one method of addressing these issues. Here, we describe the allelopathic activity of itchgrass (Rottboellia cochinchinensis), which can inhibit the seed germination and growth of weeds. Farmers in Lampang, northern Thailand, have been cultivating itchgrass and using it as a mulching material to control other weeds in vegetable fields. It has long been observed that itchgrass interferes with the growth of other plants. This study showed that the density of weed species in the itchgrass‐infested areas was lower than that in the itchgrass‐uninfested areas. The shoot and root growth of Bidens pilosa, Mimosa pudica, Ageratum conyzoides, Echinochloa crus‐galli, Oryza sativa var. RD 6, and Lactuca sativa var. OP were significantly reduced in soil previously planted with itchgrass. Water‐soluble extracts from all parts of itchgrass had inhibitory effects on the growth of some test plants. Allelochemicals from itchgrass can inhibit seed germination and plant growth better at a 1 cm distance than at a 3 cm and 5 cm distance from itchgrass. Our results suggest that itchgrass has a strong competitive ability and possible allelopathic activity to other plant species. The allelopathic activity of itchgrass in the soil can influence the germination of adjacent species, causing reduced growth of seedlings.
Tolerance of black, cranberry, kidney, and white bean to cloransulam‐methyl
Authors: SOLTANI NADER , SHROPSHIRE CHRISTY , SIKKEMA PETER H.
Published: February 2010

The level of tolerance of various market classes of dry bean to cloransulam‐methyl is not known. Three field studies were conducted in Ontario, Canada during 2007 and 2008 to determine the level of tolerance of black, cranberry, kidney, and white bean to the pre‐emergence (PRE) and postemergence (POST) application of cloransulam‐methyl at 17.5, 35, and 70 g ai ha−1. Cloransulam‐methyl applied at 17.5, 35, and 70 g ha−1 caused between 13 and 23% injury in black, cranberry, kidney, and white bean, respectively. Cloransulam‐methyl applied at 17.5, 35, and 70 g ha−1 reduced the shoot dry weight by between 16 and 28% compared to the untreated control. Cloransulam‐methyl applied PRE reduced the height of black bean by 27% and the height of cranberry bean by 25% at 70 g ha−1 and reduced the height of white bean by 19% at 35 g ha−1 and by 37% at 70 g ha−1. Cloransulam‐methyl applied PRE reduced the yield of black bean by 29% at 35 g ha−1 and by 43% at 70 g ha−1, reduced the yield of cranberry bean by 43% at 70 g ha−1, and reduced the yield of white bean by 36% at 35 g ha−1 and by 54% at 70 g ha−1. Based on these results, there is not an adequate margin of crop safety for the PRE and POST application of cloransulam‐methyl in black, cranberry, kidney, and white bean at the rates evaluated.
Trade‐off between antibiotic resistance and biological fitness in Acinetobacter sp. strain DR1
Authors: Kang Yoon‐Suk , Park Woojun
Published: February 2010

Rifampicin, a bactericidal antibiotic drug, is routinely used to make an environmental recipient selective in laboratory‐conjugation experiments. We noticed, inadvertently, that the rifampicin‐resistant Acinetobacter sp. strain DR1, a recently discovered hexadecane‐degrading environmental isolate, exhibited a substantial loss of quorum sensing signalling. The domesticated ampicillin‐resistant strain, DR1, evidenced more dramatic phenotypic changes than were observed in the rifampicin‐resistant cells: a complete loss of quorum sensing, a loss in swimming and swarming motilities, poor fimbrial expression, increased rigidity in membrane fatty acid composition and reduced hexadecane degradation capability. Interestingly, the motility of strain DR1 grown adjacent to a streptomycin‐producing Streptomyces griceus was permanently abrogated, where this change was heritable and other phenotypic changes could not be detected. In this study, we have reported for the first time that the in situ acquisition of antibiotic resistance may reduce biological fitness, including losses in the production of quorum sensing signals, motility and substrate utilization, and each antibiotic is associated with different degrees of phenotypic and genetic alterations. Our data also suggested that the domestication of environmental isolates should be approached with caution, as there are phenotypic variations in antibiotic‐resistant cells that might not be noticeable unless all possible phenotypic assays are conducted.
Danish Ethical Demands and French Common Goods: Two Moral Philosophies
Authors: MacIntyre Alasdair
Published: February 2010

Is Knud Eiler Løgstrup's conception of the ethical demand as deeply incompatible with the central theses of 20th century French Thomistic moral philosophy as it seems to be? Discussion of this question requires attention to both the Lutheran and the phenomenological background of Løgstrup's thought; a consideration of the Danish and French social contexts in which the claims of the two moral philosophies were developed; and an enquiry into how far aspects of each are complementary to rather than in conflict with the other. An historical explanation for the genesis of the kind of normativity without norms defended by both Løgstrup and Levinas is proposed.
Tuition Fees and the Dual Income Tax: The Optimality of the Nordic Income Tax System Reconsidered
Authors: Schindler Dirk
Published: February 2010

We examine the optimal tax and education policy in the case of a dual income tax. Incorporating an educational sector and endogenous capital taxation, we show that the results in Nielsen and Sørensen’s study are vulnerable with respect to assumptions on the elasticity of unskilled labor supply. Tax progressivity results residually, whereas educational policy guarantees an optimal tax wedge on, but not necessarily efficiency in, educational investment. The less elastic are the unobservable educational investment and skilled labor (the latter relative to unskilled labor supply), and the more educational policy cares about the skilled labor supply, the more progressive the tax system will be. Education will be subsidized on a net basis if the complementarity effect on the skilled labor supply is strong and important; however, there is also an offsetting substitutability effect of the unskilled labor supply at play.
TREX1 mutations are not associated with sporadic inclusion body myositis
Authors: Cox F. M. , Boon E. M. J. , Van Der Lans C. A. C. , Bakker E. , Verschuuren J. J. G. M. , Badrising U. A.
Published: February 2010

Background:  Sporadic inclusion body myositis (sIBM) is the most frequent acquired myopathy above the age of fifty. The exact mechanism causing this disease is not known, but immune‐mediated features are prominent and are probably to play a role in its pathogenesis. TREX1 gene mutations are associated with a large range of autoimmune diseases, such as systemic lupus erythematosus. We investigated whether mutations in the TREX1 gene were associated with sIBM.

Methods:  Fifty‐four patients with sIBM were tested for TREX1 mutations by direct sequencing.

Results:  All 54 patients tested negative for pathogenic mutations in the TREX1 gene. One presumed non‐pathogenic polymorphism was found in 42 out of 54 patients.

Conclusion:  TREX1 mutations do not play a role in the pathogenesis of sIBM.
The Hispanic Americans Baseline Alcohol Survey (HABLAS): Predictors of Alcohol Attitudes and Expectancies in Hispanic National Groups
Authors: Mills Britain A. , Caetano Raul
Published: February 2010

Background:  Multiple theoretical frameworks identify attitudes and expectancies as important predictors of alcohol behavior. Few studies have examined demographic predictors of these evaluative and belief‐based cognitive mediators in the general population, and none have examined them in large‐scale studies of Hispanics, a group at higher risk for drinking behavior and problems. This study probes the extent to which dimensions of attitudes and expectancies share common demographic predictors in a large sample of Puerto Ricans, Cuban‐Americans, Mexican‐Americans, and South/Central Americans.

Methods:  The 2006 Hispanic Americans Baseline Alcohol Survey (HABLAS) used a multistage cluster sample design to interview 5,224 individuals randomly selected from households in Miami, New York, Philadelphia, Houston, and Los Angeles. This study focused on 2,773 respondents self‐identified as current drinkers. Multiple linear regression was used to identify predictors of positive and negative dimensions of attitudes and expectancies, controlling for various background variables.

Results:  Religious affiliation selectively predicted alcohol attitudes, with Catholics having more positive and fewer negative attitudes than other religious groups. Hispanic group selectively predicted alcohol expectancies, with Cuban‐Americans having less positive and less negative expectancies than other groups. Being U.S.‐born or male predicted more positive attitudes and expectancies, but birthplace and gender did not predict negative dimensions of attitudes or expectancies. Higher acculturation and more education were linked to a decreased tendency to agree with any item. Age was positively and negatively associated with negative expectancies and positive attitudes, respectively, and having never been married, higher income, and unemployment were each linked to fewer negative attitudes.

Conclusions:  Although there is some overlap, attitudes and expectancies are influenced by different sociodemographic variables. Positive and negative dimensions of those constructs also show distinct patterns of relations. Prevention and treatment programs targeting cognitive mediators of behavior should be mindful of these differential determinants and future modeling endeavors should incorporate them.
Creating a Curtain of Protection: Nurses’ Experiences of Grief Following Patient Death
Authors: Gerow Lisa , Conejo Patricia , Alonzo Amanda , Davis Nancy , Rodgers Susan , Domian Elaine Williams
Published: February 2010

Purpose: To describe the lived experience of nurses surrounding the death of their patients.

Design: A qualitative phenomenologic approach was used for the interview and analysis framework. Methods to ensure trustworthiness and rigor were incorporated into the design.

Methods: Using semistructured interviews and phenomenologic concepts, the investigators interviewed 11 registered nurses where data was analyzed using methods of Heideggerian hermeneutical analysis and van Manen's progression of reflection, description, writing, and rewriting.

Findings: Four themes were identified: (a) Reciprocal relationship transcends professional relationship; (b) initial patient death events are formative; (c) nurses’ coping responses incorporate spiritual worldviews and caring rituals; and (d) remaining “professional” requires compartmentalizing of experience.

Conclusions: Nurses create a curtain of protection to mitigate the grieving process and allow them to continue to provide supportive nursing care.

Clinical Relevance: By developing understanding of the grieving and coping processes, nursing faculty, administrators, and leaders can provide better learning opportunities and more supportive practice environments for the professional nurse.
Lifestyle factors and hand eczema in a Swedish adolescent population
Authors: Röhrl Kari , Stenberg Berndt
Published: February 2010

Background: Hand eczema risk factors are potentially associated with lifestyle, and changes in lifestyle may influence the prevalence of this condition.

Objectives: To report potential lifestyle risk factors and their association with hand eczema.

Patients/Materials/Methods: Cross‐sectional questionnaire survey and standard patch test among Swedish upper secondary school children. The participation rate was 81% (6095/7543) for the questionnaire and 59% (4439/7543) for the test.

Results: Girls reported piercing (84% versus 18%), tattooing (6% versus 3%), smoking (24% versus 16%) and vegetarianism (21% versus 7%) significantly more often than boys. Girls had significantly more hand eczema (7% versus 4%) than boys. Besides female sex (OR 2.0), allergic rhinitis (OR 1.8), flexural eczema (OR 4.5), and positive nickel test (OR 1.7) were significant risk factors in multivariate analysis. Piercing entailed a decreased risk (OR 0.6). Other lifestyle practices had no association with hand eczema. Vegetarian diet and dental braces which potentially increase oral nickel exposure were not associated with hand eczema prevalence in nickel sensitized individuals.

Conclusions: The studied lifestyle practices were more prevalent in girls. Smoking, tattooing, and diet were not associated with the occurrence of hand eczema.
9‐Deazaguanine derivatives connected by a linker to difluoromethylene phosphonic acid are slow‐binding picomolar inhibitors of trimeric purine nucleoside phosphorylase
Authors: Breer Katarzyna , Glavaš‐Obrovac Ljubica , Suver Mirjana , Hikishima Sadao , Hashimoto Mariko , Yokomatsu Tsutomu , Wielgus‐Kutrowska Beata , Magnowska Lucyna , Bzowska Agnieszka
Published: February 2010

Genetic deficiency of purine nucleoside phosphorylase (PNP; EC 2.4.2.1) activity leads to a severe selective disorder of T‐cell function. Therefore, potent inhibitors of mammalian PNP are expected to act as selective immunosuppressive agents against, for example, T‐cell cancers and some autoimmune diseases. 9‐(5′,5′‐difluoro‐5′‐phosphonopentyl)‐9‐deazaguanine (DFPP‐DG) was found to be a slow‐ and tight‐binding inhibitor of mammalian PNP. The inhibition constant at equilibrium (1 mm phosphate concentration) with calf spleen PNP was shown to be  = 85 ± 13 pm (pH 7.0, 25 °C), whereas the apparent inhibition constant determined by classical methods was two orders of magnitude higher ( = 4.4 ± 0.6 nm). The rate constant for formation of the enzyme/inhibitor reversible complex is (8.4 ± 0.5) × 105 m−1·s−1, which is a value that is too low to be diffusion‐controlled. The picomolar binding of DFPP‐DG was confirmed by fluorimetric titration, which led to a dissociation constant of 254 pm (68% confidence interval is 147–389 pm). Stopped‐flow experiments, together with the above data, are most consistent with a two‐step binding mechanism: E + I ↔ (EI) ↔ (EI)*. The rate constants for reversible enzyme/inhibitor complex formation (EI), and for the conformational change (EI) ↔ (EI)*, are kon1 = (17.46 ± 0.05) × 105 m−1·s−1, koff1 = (0.021 ± 0.003) s−1, kon2 = (1.22 ± 0.08) s−1 and koff2 = (0.024 ± 0.005) s−1, respectively. This leads to inhibition constants for the first (EI) and second (EI)* complexes of Ki = 12.1 nM (68% confidence interval is 8.7–15.5 nm) and  = 237 pm (68% confidence interval is 123–401 pm), respectively. At a concentration of 10−4 m, DFPP‐DG exhibits weak, but statistically significant, inhibition of the growth of cell lines sensible to inhibition of PNP activity, such as human adult T‐cell leukaemia and lymphoma (Jurkat, HuT78 and CCRF‐CEM). Similar inhibitory activities of the tested compound were noted on the growth of lymphocytes collected from patients with Hashimoto’s thyroiditis and Graves’ disease. The observed weak cytotoxicity may be a result of poor membrane permeability.
Inhibition kinetics of catabolic dehydrogenases by elevated moieties of ATP and ADP – implication for a new regulation mechanism in Lactococcus lactis
Authors: Cao Rong , Zeidan Ahmad A. , Rådström Peter , van Niel Ed W. J.
Published: February 2010

ATP and ADP inhibit, in varying degrees, several dehydrogenases of the central carbon metabolism of Lactococcus lactis ATCC 19435 in vitro, i.e. glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH), lactate dehydrogenase (LDH) and alcohol dehydrogenase (ADH). Here we demonstrate mixed inhibition for GAPDH and competitive inhibition for LDH and ADH by adenine nucleotides in single inhibition studies. The nonlinear negative co‐operativity was best modelled with Hill‐type kinetics, showing greater flexibility than the usual parabolic inhibition equation. Because these natural inhibitors are present simultaneously in the cytoplasm, multiple inhibition kinetics was determined for each dehydrogenase. For ADH and LDH, the inhibitor combinations ATP plus NAD and ADP plus NAD are indifferent to each other. Model discrimination suggested that the weak allosteric inhibition of GAPDH had no relevance when multiple inhibitors are present. Interestingly, with ADH and GAPDH the combination of ATP and ADP exhibits lower dissociation constants than with either inhibitor alone. Moreover, the concerted inhibition of ADH and GAPDH, but not of LDH, shows synergy between the two nucleotides. Similar kinetics, but without synergies, were found for horse liver and yeast ADHs, indicating that dehydrogenases can be modulated by these nucleotides in a nonlinear manner in many organisms. The action of an elevated pool of ATP and ADP may effectively inactivate lactococcal ADH, but not GAPDH and LDH, providing leverage for the observed metabolic shift to homolactic acid formation in lactococcal resting cells on maltose. Therefore, we interpret these results as a regulation mechanism contributing to readjusting the flux of ATP production in L. lactis.
ENERGY REQUIREMENT AND QUALITY ASPECTS OF CHINESE JUJUBE (ZIZYPHUS JUJUBA MILLER) IN HOT AIR DRYING FOLLOWED BY MICROWAVE DRYING
Authors: FANG SHUZHENG , WANG ZHENGFU , HU XIAOSONG , CHEN FANG , ZHAO GUANGHUA , LIAO XIAOJUN , WU JIHONG , ZHANG YAN
Published: February 2010

Chinese jujube samples were dried in hot air at 60C, and then switched into microwave drying of 45, 65 and 90 W at moisture contents of 50, 40 and 30%, respectively. Results indicated that the energy consumptions of combined drying at a transition point of 50% were all lower than that of microwave drying by itself at three power levels, which might be ascribed to the reduction of initial heat‐up region in microwave drying of combined drying. As compared with hot air drying alone, the combined drying can save energy consumption up to about 55%. Combined drying was higher in the rehydration capacity of the dried products than microwave drying alone or hot air drying alone, and is also beneficial to the preservation of vitamin C and less browning. Hot air drying followed by microwave drying of 45 W at transition point of 50% was best in terms of higher product quality with less energy consumption.

PRACTICAL APPLICATIONS

Jujube is a fruit distributed to over 30 countries around the world. Drying of jujube is energy intensive. Hot air drying alone takes too much time, requires more energy consumption and degrades the product quality, and microwave drying alone will result in more browning of the product. The combined drying – hot air drying followed by microwave drying – is a promising way to lower energy consumption and to raise product quality.
Experiencing Waterholes in an Arid Environment, with Particular Reference to the Lake Eyre Basin, Australia: a Review
Authors: SILCOCK JENNY LESLEY
Published: February 2010

The distribution and permanence of waterholes have dictated human activity and settlement patterns in the arid zone for millennia. At a fundamental level, waterholes are vital to survival in a harsh climate. The recreational value and use of waterholes are widely recognised; however, the less tangible aspects of ‘waterhole experience’ have received scant attention. This review, written whilst compiling an inventory of permanent waterbodies across the Lake Eyre Basin of Queensland and South Australia, aimed to provide a deeper understanding of the interaction of humans with water in an arid land, primarily from a settler perspective.

A large body of literature pertaining to waterholes was reviewed, including Aboriginal histories, explorer journals, accounts of early settlers, and numerous fictional and factual accounts of life in inland Australia. It becomes apparent that human appreciation of arid‐zone waterholes runs deeper than the survival imperative, and can be enriched by considering landscape aesthetics and psychology. This attraction has spawned a rich mythology centred on waterholes – permanent features in an otherwise harsh and variable environment.
The Effect of Leading Edge Curvature on a Mixed Flow Turbine Performance Under Pulsating Flow Conditions
Authors: Chen Li , Zhuge Weilin , Zhang Yangjun , Zhang Shuyong
Published: February 2010

Turbines used in turbochargers matched to reciprocating engines are under natural pulsating flow conditions, and the turbine which has a good performance under steady design condition normally cannot get the same performance in the whole engine actual working circle. Under the pulsating conditions, the incidence angle will change tremendously, thus leads to undesirable flowfield in the turbine. It is shown in some published literature that varying turbine blade inlet angle can achieve better performance characteristics. In this paper, leading edge curvature is introduced to an original mixed flow turbine, while steady and unsteady simulation models of the mixed flow turbine are built to investigate the aerodynamic performance of the original and modified turbine. Flowfield analysis shows that the leading edge curvature can make the flow less sensitive to the incidence change, and average instantaneous efficiency under pulsating flow conditions is improved, while a better overall performance of the turbine is achieved.
High Hub/Tip Ratio Centrifugal Compressors
Authors: Rodgers C. , Brown D.
Published: February 2010

During WW II the impetus of higher speed higher altitude aircraft necessitated the rapid development of advanced supercharged and turbocharged piston engines, much of the centrifugal compressor technology from which was transferred to early gas turbines. Post WW II gas turbine development was predominantly focused upon the perfection of the multistage axial compressors, with the recognition that in certain applications the combined axial–cum–centrifugal compressor (AxC) could provide a more compact engine installation. Gas Turbines with AxC compressors now fulfill a significant sector of the aviation propulsion market, plus also some industrial applications. Individual research and development of both axial and centrifugal compressors types continues to higher plateaus of performance, and is the context of extensive publications, yet in difference a scarcity of written technology prevails for the AxC compressor. This conspicuous limited exposure of AxC compressor technology fostered the motivation for this treatise, the intent being to record whatever meager AxC information at large exists, plus highlighting turbomachinery design parameters which can assist in AxC continued performance perfection. Specifically a characteristic design feature of AxC examined is the influence of large impeller hub to tip diameter ratios Є.
Multistage Compressor and Turbine Modeling for the Prediction of the Maximum Turbine Speed Resulting From Shaft Breakage
Authors: Haake M. , Fiola R. , Staudacher S.
Published: February 2010

A mathematical model for the prediction of the maximum speed of a high pressure turbine following a shaft failure event was developed. The model predicts the high pressure compressor and ducting system pre- and post-stall behavior like rotating stall and surge after the shaft breakage. The corresponding time-dependent high pressure turbine inlet conditions are used to calculate the turbine maximum speed, taking into account friction and blade&vane tip clearance variations as a result of the rearward movement of the turbine and destruction of the turbine blading. The compressor and ducting system is modeled by a 1-dimensional, stage-by-stage approach. The approach uses a finite-difference numerical technique to solve the nonlinear system of equations for continuity, momentum and energy including source terms for the compressible flow through inlet ducting, compressor and combustor. The compressor blade forces and shaft work are provided by a set of quasi steady state stage characteristics being valid for pre-stall and post-stall operations. The maximum turbine speed is calculated from a thermodynamic turbine stand-alone model, derived from a performance synthesis program. Friction and blade&vane tip clearance variations are determined iteratively from graphical data depending on the axial rearward movement of the turbine. The compressor and ducting system model was validated in pre-stall and post-stall operation mode with measured high pressure compressor data of a modern 2-shaft engine. The turbine model was validated with measured intermediate pressure shaft failure data of a 3-shaft engine. The shaft failure model was applied on a modern 2-shaft engine. The model was used to carry out a sensitivity study to demonstrate the impact of control system reactions on the resulting maximum high pressure turbine speed following a shaft failure event.
The Discrete Adjoint of a Turbomachinery RANS Solver
Authors: Frey Christian , Kersken Hans-Peter , Nu¨rnberger Dirk
Published: February 2010

Since adjoint flow solvers allow for the computation of sensitivities of global flow parameters under geometric variations in an amount of time which is nearly independent of the number of geometric parameters, automatic shape optimization can be accelerated considerably by the use of an adjoint solver. In this article, a systematic approach for the development of an exact discrete adjoint of a turbomachinery flow solver is described. By using finite differences to differentiate the numerical fluxes, the problems associated with automatic and hand differentiation are circumvented. Moreover, a general treatment of the adjoint numerical boundary conditions is presented. As a result, an exact adjoint boundary condition for the conservative mixing planes is obtained. In combination with nonreflecting boundary conditions the latter are crucial for accurate flow simulations in turbomachinery. The adjoint is validated on the basis of a transonic compressor stage.
Static and Dynamic Analysis of 48″ Steel Last Stage Blade for Steam Turbine
Authors: Misek Tomas , Kubin Zdenek , Duchek Karel
Published: February 2010

The 3000 rpm 48 inch blade for steam turbine has been developed with the application of new design features. The last stage moving blade was designed with integral cover, mid-span tie-boss connection, and fir-tree dovetail. Blades are continuously coupled by the blade untwist due to the centrifugal force, so vibration control and increased structural damping are provided. The last stage airfoil was optimized from view of minimization of its centrifugal force which helped to reach higher safety factors. The blade was well tuned in order to have eigen-frequencies safely away from possible excitation. Because of connection members, the number of the resonant vibration modes can be reduced by virtue of the vibration characteristics of the circumferentially continuous blades. In order to develop the 3000 rpm 48 inch blade, the latest analysis methods were applied to predict dynamic behavior of the bladed structure. Coupled rotor-blade analysis was also aim of the attention. To validate calculated results the verification measurement such as rotational vibration tests was carried out in the high-speed test rig. The test rotor was fitted with the actual full scale 48″ blades. Relation of the friction damping of the bladed structure on amount of excitation level was also monitored and evaluated.
Validating Numerical CFD Simulations With Experimental Data for Turbulence Phenomena in Axial Flow Gas Turbine Diffusers
Authors: Zarifi-Rad Farrokh , Vajihollahi Hamid , O’Brien James
Published: February 2010

Scale models give engineers an excellent understanding of the aerodynamic behavior behind their design; nevertheless, scale models are time consuming and expensive. Therefore computer simulations such as Computational Fluid Dynamics (CFD) are an excellent alternative to scale models. One must ask the question, how close are the CFD results to the actual fluid behavior of the scale model? In order to answer this question the engineering team investigated the performance of a large industrial Gas Turbine (GT) exhaust diffuser scale model with performance predicted by commercially available CFD software. The experimental results were obtained from a 1:12 scale model of a GT exhaust diffuser with a fixed row of blades to simulate the swirl generated by the last row of turbine blades five blade configurations. This work is to validate the effect of the turbulent inlet conditions on an axial diffuser, both on the experimental front and on the numerical analysis approach. The object of this work is to bring forward a better understanding of velocity and static pressure profiles along the gas turbine diffusers and to provide an accurate experimental data set to validate the CFD prediction. For the CFD aspect, ANSYS CFX software was chosen as the solver. Two different types of mesh (hexagonal and tetrahedral) will be compared to the experimental results. It is understood that hexagonal (HEX) meshes are more time consuming and more computationally demanding, they are less prone to mesh sensitivity and have the tendancy to converge at a faster rate than the tetrahedral (TET) mesh. It was found that the HEX mesh was able to generate more consistent results and had less error than TET mesh.
Identification in Rotordynamics: Uncertainty Analysis and Quality Estimation
Authors: Wang Qingyu , Pettinato Brian , Maslen Eric
Published: February 2010

Critical to the result value of an identification process is establishment of the reliability or accuracy of the identified parameters. Uncertainty in the identification process can stem both from uncertainty in the analytical model and from uncertainty in the test data. The uncertainty propagation turns out to be difficult to estimate due to rather complicated identification process and the dimension of the analytical model. Currently, there is no uncertainty analysis and quality estimation available in the literature to the author’s knowledge for model-based identification in rotordynamics. This paper borrows linear fractional transformation (LFT) and μ-analysis from the controls community to perform this job. The basic idea is that the uncertainty of the identified result can be expressed as a system with uncertainties, and therefore quality estimation is equal to bounding the gain of this system. This system is built in two steps: first, different types of source uncertainties are expressed as LFT format, and second, the whole identification process with uncertainties is transformed into a single LFT format. μ-analysis is then used to bound the gain of this LFT. The uncertainty analysis and bounding algorithm are illustrated with the same experimental data used in the last paper, for both model-based and direct measurement methods.
Development of Adjoint Solvers for Engineering Gradient-Based Turbomachinery Design Applications
Authors: Marta Andre C. , Shankaran Sriram , Holmes D. Graham , Stein Alexander
Published: February 2010

High-fidelity computational fluid dynamics (CFD) are common practice in turbomachinery design. Typically, several cases are run with manually modified parameters based on designer expertise to fine-tune a machine. Although successful, a more efficient process is desired. Choosing a gradient-based optimization approach, the gradients of the functions of interest need to be estimated. When the number of variables greatly exceeds the number of functions, the adjoint method is the best-suited approach to efficiently estimate gradients. Until recently, the development of CFD adjoint solvers was regarded as complex and difficult, which limited their use mostly to academia. This paper focuses on the problem of developing adjoint solvers for legacy industrial CFD solvers. A discrete adjoint solver is derived with the aid of an automatic differentiation tool that is selectively applied to the CFD code that handles the residual and function evaluations. The adjoint-based gradients are validated against finite-difference and complex-step derivative approximations.
Study on Probabilistic Model of GH4133B for Fatigue-Creep Failure
Authors: Hu Dianyin , Wang Rongqiao
Published: February 2010

GH4133B is a nickel-base superalloy which was developed for use in the manufacture of aero-engine turbine disks and other high-temperature components. Since these components are operated at high temperature and under cyclic loading, damage resulting from fatigue-creep interaction is the main factor. The situation is often simulated in laboratories at high temperature low-cycle fatigue. The interactive effect between different loading levels should be considered. The fatigue-creep experiments for alloy GH4133B at 600 Celsius degree have been carried out at continuous cyclic creep (CF) loading to investigate the interaction of creep damage and fatigue damage. Fracture surfaces are examined under the scanning electron microscope (SEM). Then a nonlinear fatigue-creep failure criterion function proposed by Hongyin Mao is employed to fit the experimental data. The probabilistic model of GH4133B under CF loading is established based on the deterministic failure function. Firstly, the random variables influencing the fatigue-creep life and values of the distribution parameters are investigated. Then fatigue-creep damage interaction is discussed and a linear damage accumulation rule is considered, according to which the limit state function used to express the probability of failure is proposed. Lastly, reliability analysis under fatigue-creep failure is proceeded by applying analytical and simulation methods. Furthermore, the random variable with low sensitivity index through the sensitivity analysis can be treated as deterministic parameter during the reliability analysis and reliability design in order to improve the computing efficiency.