bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pairwise Comparisons Using Trimmed Means or M‐Estimators when Working with Dependent Groups
Authors: Wilcox Rand R. 
Published: May 2007

AbstractFor J dependent groups, let θj, j = 1, …, J, be some measure of location associated with the jth group. A common goal is computing confidence intervals for the pairwise differences, θj — θk, j < k, such that the simultaneous probability coverage is 1 — α. If means are used, it is well known that slight departures from normality (as measured by the Kolmogorov distance) toward a heavy‐tailed distribution can substantially inflate the standard error of the sample mean, which in turn can result in relatively low power. Also, when distributions differ in shape, or when sampling from skewed distributions with relatively light tails, practical problems arise when the goal is to obtain confidence intervals with simultaneous probability coverage reasonably close to the nominal level. Extant theoretical and simulation results suggest replacing means with trimmed means. The Tukey‐McLaughlin method is easily adapted to the problem at hand via the Bonferroni inequality, but this paper illustrates that practical concerns remain. Here, the main result is that the percentile t bootstrap method, used in conjunction with trimmed means, gives improved probability coverage and substantially better power. A method based on a one‐step M‐estimator is also considered but found to be less satisfactory.
Overlapping Clusters of Tuberculosis Contacts: An Improved Sampling Strategy
Authors: Osahan Sukhminder S. 
Published: May 2007

AbstractA two stage without replacement strategy is proposed for estimating the population mean of overlapping clusters of contacts of tuberculosis cases. This sampling strategy is an improvement over the two sampling strategies proposed by SINGH (1988). A numerical illustration is provided by taking two populations of tuberculosis contacts from New York City; the percentage gain in efficiency varies from 3.70 to 24.99. The proposed improved sampling strategy may be useful to other contagious diseases in the different fields of biomedical sciences or similar situations in other fields.
A Generalized Allometric Model for Determining Length‐Weight Relationship
Authors: Venugopalan R. , Prajneshu  
Published: May 2007

AbstractWell‐known allometric model is critically reviewed for determining the length‐weight relationship. Procedure to be followed for applying this model under the assumption of multiplicative as well as additive error is discussed. The possibility of autocorrelations in error term is explored. It has been demonstrated that the usual allometric relationship does not always work satisfactorily. Accordingly, a generalization of this model is studied in detail. As an illustration, this generalized version of allometric model is used to determine the length‐weight relationship of some data on the Indian pearl oyster.
Prediction of Growth: A Hierarchical Bayesian Approach
Authors: Arjas Elja , Liu Liping , Maglaperidze Niko 
Published: May 2007

AbstractA nonparametric hierarchical growth curve model is proposed. Different levels in the model hierarchy are intended to correspond to different sources of variation in an individual's growth. The nonparametric character of the model offers considerable flexibility in fitting the growth curves to empirical data. Here the emphasis is on prediction, and for this purpose the adopted Bayesian inferential approach seems particularly natural and efficient. A Markov chain Carlo method is used to perform the numerical computations. As an illustration of the techniques, we consider the growth of children, during their first two years.
A Technical Note on the Power Determination for Fisher's Combination Test
Authors: Wassmer Gernot 
Published: May 2007

AbstractIn a recent paper, Banik, Köhne, and Bauer (1996) investigated the use of Fisher's combination test for two stage sampling in terms of its power as compared to the optimal test in the pooled sample. The distributional assumptions corresponded to the application of paired comparisons and parallel groups t tests in the classical nonadaptive scenario. Allowing early stopping in favor of H0, as described in Bauer and Köhne (1994), modifies this test procedure and possibly reduces the sample size. For power calculations they noted a technical problem in integration arising from function singularities. This note provides a technically feasible solution for power calculations in these and other cases using SAS/IML software. Some results, e.g. concerning a potential gain in power when allowing for early stopping are presented.
A Stochastic Process and Generalized Distributions for the Study of Oviposition Evolution of a Parasite
Authors: Janardan K. G. 
Published: May 2007

AbstractThis paper considers a generalized birth process {Xm(t), t > 0} and presents a new stochastic model for the number of eggs laid by a parasite on a host. Also, given an underlying distribution for the number of visits between parasites and a host, this distribution is generalized by the distribution of the number of eggs per visit laid on the host. If a certain number of eggs are already present on the host, a parasite such as a Japanese weevil, may avoid oviposition in subsequent visits (see JANARDAN (1980)) to the same host. A class of generalized distributions are presented to model such situations. The case of a single egg laying parasite and a Poisson distribution for the number of visits of the parasite to the same host yields a distribution of particular interest. In order to develop this model, certain lemmas are derived. Finally a characteristic property of this stochastic model is presented.
Linear Discriminant Functions for Stationary Time Series
Authors: Krzyśko Mirosłw , Wołński Waldemar 
Published: May 2007

AbstractOptimal classification rules based on linear functions which maximize the Chernoff distance, or the Morisita distance, or the Kullback‐Leibler distance are studied here. We obtain an expression for the optimal linear discriminant function and show that the resulting linear procedure belongs to the Anderson‐Bahadur admissible class. For the comparison of discriminant rules we use some index which is the measure of the accuracy of a given class of discriminant procedures. The asymptotic form of the discriminant function is also studied.
Computing Projections into Cones Generated by a Matrix
Authors: Frick H. 
Published: May 2007

AbstractA method is described for computing orthogonal projections into finitely generated cones. This method can be used to solve nonnegative least squares approximation problems, to find the multivariate onesided Maximum Likelihood estimator and also determines the most stringent somewhere most powerful test of Schaafsma. The gist of the procedure is the unconstrained maximization of a numerically simple function. This function has a global maximum and allows an uncomplicated maximum search since local maxima do not exist. The maximum can be obtained after a finite number of iterations.
Interval Estimation for Ratios in Bioequivalence Trials
Authors: Chen Keh‐Wei , Li Gang , Sun Yanqing , Chow Shein‐Chung 
Published: May 2007

AbstractThe problem for assessment of equivalence in variability of bioavailability between two drug products is considered. An exact confidence region for the ratio between intrasubject variabilities is derived when the intersubject variance is known. When the intersubject variance is unknown, a large sample approximation is considered. The proposed method for assessing equivalence in variability of bioavailability appears to be asymptotically uncorrelated with the sample mean ratio for average bioavailabilty. As a result, the proposed method in conjunction with the sample mean ratio method can be utilized for assessing population bioequivalence. An example concerning a bioequivalence trial with 24 healthy volunteers is presented to illustrate the proposed method.
Engineering bacteria for production of rhamnolipid as an agent for enhanced oil recovery
Authors: Wang Qinhong , Fang Xiangdong , Bai Baojun , Liang Xiaolin , Shuler Patrick J. , Goddard William A. , Tang Yongchun 
Published: May 2007

AbstractRhamnolipid as a potent natural biosurfactant has a wide range of potential applications, including enhanced oil recovery (EOR), biodegradation, and bioremediation. Rhamnolipid is composed of rhamnose sugar molecule and β‐hydroxyalkanoic acid. The rhamnosyltransferase 1 complex (RhlAB) is the key enzyme responsible for transferring the rhamnose moiety to the β‐hydroxyalkanoic acid moiety to biosynthesize rhamnolipid. Through transposome‐mediated chromosome integration, the RhlAB gene was inserted into the chromosome of the Pseudomonas aeruginosa PAO1‐rhlA− and Escherichia coli BL21 (DE3), neither of which could produce rhamnolipid. After chromosome integration of the RhlAB gene, the constitute strains P. aeruginosa PEER02 and E. coli TnERAB did produce rhamnolipid. The HPLC/MS spectrum showed that the structure of purified rhamnolipid from P. aeruginosa PEER02 was similar to that from other P. aeruginosa strains, but with different percentage for each of the several congeners. The main congener (near 60%) of purified rhamnolipid from E. coli TnERAB was 3‐(3‐hydroxydecanoyloxy) decanoate (C10–C10) with mono‐rhamnose. The surfactant performance of rhamnolipid was evaluated by measurement of interfacial tension (IFT) and oil recovery via sand‐pack flooding tests. As expected, pH and salt concentration of the rhamnolipid solution significantly affected the IFT properties. With just 250 mg/L rhamnolipid (from P. aeruginosa PEER02 with soybean oil as substrate) in citrate–Na2HPO4, pH 5, 2% NaCl, 42% of oil otherwise trapped was recovered from a sand pack. This result suggests rhamnolipid might be considered for EOR applications. Biotechnol. Bioeng. 2007; 98: 842–853. © 2007 Wiley Periodicals, Inc.
Cadmium removal from contaminated soil by thermally responsive elastin (ELPEC20) biopolymers
Authors: Lao U Loi , Chen Alin , Matsumoto Mark R. , Mulchandani Ashok , Chen Wilfred 
Published: May 2007

AbstractCadmium contamination of soil is a major concern in the biosphere. Beyond the suite of available physico‐chemical treatment methods, green and more efficient technologies are desired to reduce cadmium and other heavy metal contaminants to acceptable levels. Elastin‐like polypeptides (ELP) composed of a polyhistidine domain (ELPH12) can be used as an environmentally benign chelating agent for ex situ soil washing. However, ELPH12 is relatively non‐selective. A biopolymer with metal‐binding domains that have stronger affinity, capacity, and selectivity would have distinct advantages. The aim of this work is to investigate the use of a new generation of ELP biopolymer, ELPEC20, containing synthetic phytochelatin (EC) as the metal‐binding domain for ex situ soil washing. ELPEC20 was shown to bind cadmium more effectively and selectively than ELPH12. The binding constant of ELPEC20 is an order of magnitude higher and the binding capacity is fivefold higher than ELPH12. In contrast to ELPH12, no decrease in cadmium binding was observed in the presence of other competing metal ions. The improved selectivity and binding capacity provided by ELPEC20 were directly reflected in the enhanced cadmium extraction efficiency from contaminated soil. In batch washing studies up to 62% of the bound cadmium was removed by ELPEC20 while less than 12% was removed by ELPH12. Cadmium was removed not only from the exchangeable fraction but also the oxidizable fraction. The high‐affinity binding sites of ELPEC20 also results in very rapid extraction with complete removal achieved within 1 h, suggesting that ELPEC20 could be used as part of a rapid (short retention time) technology with minimum possibility for the biodegradation of biopolymers. Biotechnol. Bioeng. 2007;98: 349–355. © 2007 Wiley Periodicals, Inc.
Self‐expanding intracoronary stent for symptomatic myocardial bridging
Authors: Ahmed S. Hinan , Khawaja Shazib N. , Husain Nadeem M. , Panayiotou Hercules 
Published: May 2007

AbstractMyocardial bridging has been recognized as a potential cause of symptoms of angina, arrhythmias and even infarction. Various treatment strategies including beta‐blockers, surgery and more recently intra‐coronary stents have been used to manage bridging. We report a novel case of use of self‐expanding stent for myocardial bridging in a patient with symptoms of angina and ischemia on nuclear imaging. We further present the 18‐month follow up showing minima in‐stent stenosis. To our knowledge, this is the first report of using a self‐expanding stent in myocardial bridging. The use of self‐expanding stents could be a potential treatment for symptomatic myocardial bridging. © 2007 Wiley‐Liss, Inc.
Flow Characteristics and Shannon Entropy Analysis of Dense‐Phase Pneumatic Conveying of Pulverized Coal with Variable Moisture Content at High Pressure
Authors: Liang C. , Zhao C.‐S. , Chen X.‐P. , Pu W.‐H. , Lu P. , Fan C.‐L. 
Published: May 2007

AbstractExperiments consisting of dense‐phase pneumatic conveying of pulverized coal using nitrogen were carried out in an experimental test facility, with a conveying pressure of up to 4 MPa. The influences of the conveying differential pressure, the coal moisture content, the gas volume flow rate and the superficial velocity, on the solid‐gas ratios, were investigated. The Shannon entropy analysis of the pressure fluctuation time series was developed to reveal the flow characteristics. By investigation of the distribution of the Shannon entropy at different conditions, the flow stability and the evolutional tendency of Shannon entropy, in different regimes and regime transition processes, were revealed, and the relationship between Shannon entropy and the flow regime was also established. The results indicate that the solid‐gas ratio and the Shannon entropy rise with increases in conveying differential pressure. The solid‐gas ratio and the Shannon entropy reveal preferable correlation with the superficial gas velocity. Shannon entropy is different for different flow regimes, and can be used to identify the flow regimes. Both the mass flow rate and the Shannon entropy, decrease with increases in moisture content. Shannon entropy analysis is a feasible approach to researching the characteristics of the flow regime, the flow stability and the flow regime transitions in dense‐phase pneumatic conveying systems, at high pressure.
Polymorphism of N,N′′‐Diacetylbiuret Studied by Solid‐State 13C and 15N NMR Spectroscopy, DFT Calculations, and X‐ray Diffraction
Authors: Macholl Sven , Lentz Dieter , Börner Frank , Buntkowsky Gerd 
Published: May 2007

AbstractThe molecular configuration and crystal structure of solid polycrystalline N,N′′‐diacetylbiuret (DAB), a potential nitrogen‐rich fertilizer, have been analyzed by a combination of solid‐ and liquid‐state NMR spectroscopy, X‐ray diffraction, and DFT calculations. Initially a pure NMR study (“NMR crystallography”) was performed as available single crystals of DAB were not suitable for X‐ray diffraction. Solid‐state 13C NMR spectra revealed the unexpected existence of two polymorphic modifications (α‐ and β‐DAB) obtained from different chemical procedures. Several NMR techniques were applied for a thorough characterization of the molecular system, revealing chemical shift anisotropy (CSA) tensors of selected nuclei in the solid state, chemical shifts in the liquid state, and molecular dynamics in the solid state. Dynamic NMR spectroscopy of DAB in solution revealed exchange between two different configurations, which raised the question, is there a correlation between the two different configurations found in solution and the two polymorphic modifications found in the solid state?By using this knowledge, a new crystallization protocol was devised which led to the growth of single crystals suitable for X‐ray diffraction. The X‐ray data showed that the same symmetric configuration is present in both polymorphic modifications, but the packing patterns in the crystals are different. In both cases hydrogen bonds lead to the formation of planes of DAB molecules. Additional symmetry elements, a two‐fold screw in the case of α‐DAB and a c‐glide plane in the case of β‐DAB, lead to a more symmetric (α‐DAB) or asymmetric (β‐DAB) intermolecular hydrogen‐bonding pattern for each molecule.
A CE assay for the detection of agonist‐stimulated adenylyl cyclase activity
Authors: Cunliffe Jennifer M. , Whorton Matthew R. , Sunahara Roger K. , Kennedy Robert T. 
Published: May 2007

AbstractA CE assay was developed for the detection of adenylyl cyclase (AC) activity stimulated at the AC and G protein‐coupled receptor (GPCR) level. In the assay, cell membranes overexpressing GPCR and/or AC were incubated with modulators and substrate ATP to produce cAMP in a dose‐dependent manner. In both the CE‐UV and a radiochemical assay, the addition of forskolin (FSK) resulted in a two‐ to three‐fold maximum increase in AC activity with EC50s of 4.2 ± 0.7 and 2.4 ± 0.7 μM, respectively, demonstrating that similar results were obtained by both assays. GPCR activation was also detected using cell membranes overexpressing AC and the β2‐adrenergic receptor (β2AR) fused to the stimulatory G protein. Terbutaline (β2AR agonist) increased the basal rate of cAMP formation 1.7 ± 0.1‐fold resulting in an EC50of 62 ± 10 nM. The assay's ability to detect antagonists is demonstrated by the expected right‐shifted EC50of terbutaline by the β2AR antagonist propranolol. The CE‐UV assay offers advantages over the traditional radioactivity assay in terms of safety and labor.
DRIVE – The Future of Automotive Power: Fuel Cells Perspective
Authors: Düsterwald H. G. , Günnewig J. , Radtke P. 
Published: May 2007

AbstractThe automotive propulsion technology market is likely to experience significant change over the next 10 to 15 years, with today's incumbent internal combustion engines (ICE) coming under attack from a multitude of alternative technologies. In the short term, these will mainly be hybrid drive trains. In the longer term, fuel cells may emerge as the strongest challengers. New fuels like natural gas, biodiesel, and hydrogen will challenge the current dominance of oil‐based fuels. The McKinsey DRIVE study assesses the perspectives of conventional and alternative power trains and their world market potential over the next 15 years, deriving implications for OEMs, suppliers, and the fuel industry.
Restructuring health services in Canada: Challenges for policy makers, planners and managers in the eighties
Authors: Crichton Anne 
Published: May 2007

AbstractIs downsizing the latest jargon word applied to rationalization, a new concept or a different manifestation of a long term trend in health services management? At present, Canada is struggling to implement feasible reductions of expansionary pressures in the health care system. While provincial governments tend to see the issue as one of controlling chronic excess demand, federal government is still concerned to ensure free access to care on an equitable basis. Thus the problems of downsizing can be expressed by the provinces in terms of an ideological struggle with an unfeeling central government which does not understand their problems; although all know they are really about the feasibility of continuing to provide a service to meet demand.The present economic recession enables provincial governments to appeal to their voters for support in a new way. Earlier, the appeal was to consumers to become involved in health service organization management and this policy succeeded, to a degree, where there were flourishing grass roots communities; albeit that the service continued to be driven by professionals. Now the appeal is to taxpayers for their strong support in cost cutting. This has been more successful. Provincial governments are now permitted to ‘touch the untouchables’, that is to downsize the medical profession and previously sacrosanct health care institutions. They also are exploring the feasibility of introducing a two‐tier system which would provide basic care for everyone and extra care for those able to pay, thus side‐stepping federal conditions. By reorganizing support in this way, provincial governments have extended the range of policy choices, and two types of planning, the rational and the political, have now become combined into strategic management activity.
Identification of novel Runx2 targets in osteoblasts: Cell type‐specific BMP‐dependent regulation of Tram2
Authors: Pregizer Steven , Barski Artem , Gersbach Charles A. , García Andrés J. , Frenkel Baruch 
Published: May 2007

AbstractRunx2 is an osteoblast master transcription factor and a target for bone morphogenetic protein (BMP) signaling, but our knowledge of events downstream of Runx2 is limited. In this study, we used ChIP Display to discover seven novel genomic regions occupied by Runx2 in living MC3T3‐E1 osteoblastic cells. Six of these regions are found within or up to 1‐kb away from annotated genes, but only two are found within 5′‐gene flanking sequences. One of the newly identified Runx2 target genes is Tram2, whose product facilitates proper folding of type I collagen. We demonstrate that Tram2 mRNA is suppressed in non‐osteoblasts when Runx2 is over‐expressed, and that this suppression is alleviated upon treatment with BMP‐2. Moreover, we show that BMP‐induced Runx2 expression in the C3H10T1/2, ST2, C2C12, and MC3T3‐E1 cell lines coincides with an increase in Tram2 mRNA levels. Thus, Runx2 may regulate Tram2 expression in a BMP‐dependent manner, and Tram2 may participate in the overall osteogenic function of Runx2. Among the other Runx2 target genes discovered in this study are Lnx2, an intracellular scaffolding protein that may play a role in Notch signaling, and Tnfrsf12a, a Tumor Necrosis Factor receptor family member that influences both osteoblast and osteoclast differentiation. Expanding our knowledge of Runx2 target genes, and manipulation of these genes, are warranted to better understand the regulation of osteoblast function and to provide opportunities for the development of new bone anabolics. J. Cell. Biochem. 102: 1458–1471, 2007. © 2007 Wiley‐Liss, Inc.
Helicobacter pylori as a class I carcinogen: Physiopathology and management strategies
Authors: Vogiatzi Paraskevi , Cassone Marco , Luzzi Ida , Lucchetti Chiara , Otvos Laszlo , Giordano Antonio 
Published: May 2007

AbstractThe gram‐negative bacterium Helicobacter pylori is known as a persistent colonizer of the human stomach, and probably less known is that it is also involved in extraintestinal diseases. Public awareness of its contribution in the development of gastric cancer is less than 15 years old. The efficacy of the current therapies based on antibiotics against H. pylori has been limited by difficulties such as antibiotic resistance and recurrence. As a consequence, the development of promising vaccines was prompted as the best preventive measure. Unfortunately, so far vaccines failed the transition from animal models to human trials. This keynote presentation is to provide a bird's eye view of H. pylori‐related gastric diseases, including gastric cancer, with a synthesis of the molecular mechanisms involved, and an exhaustive presentation and discussion of the current therapeutic guidelines and future strategies for prevention or therapy. J. Cell. Biochem. 102: 264–273, 2007. © 2007 Wiley‐Liss, Inc.