bluuebunny/crossref_metadata_2025 huggingface dataset:
NF-κB-mediated IAP expression induces resistance of intestinal epithelial cells to apoptosis after polyamine depletion
Authors: Zou Tongtong , Rao Jaladanki N. , Guo Xin , Liu Lan , Zhang Huifang M. , Strauch Eric D. , Bass Barbara L. , Wang Jian-Ying
Published: April 2004

Apoptosis plays a crucial role in maintenance of intestinal epithelial integrity and is highly regulated by numerous factors, including cellular polyamines. We recently showed that polyamines regulate nuclear factor (NF)-κB activity in normal intestinal epithelial (IEC-6) cells and that polyamine depletion activates NF-κB and promotes resistance to apoptosis. The current study went further to determine whether the inhibitors of apoptosis (IAP) family of proteins, c-IAP2 and XIAP, are downstream targets of activated NF-κB and play a role in antiapoptotic activity of polyamine depletion in IEC-6 cells. Depletion of cellular polyamines by α-difluoromethylornithine not only activated NF-κB activity but also increased expression of c-IAP2 and XIAP. Specific inhibition of NF-κB by the recombinant adenoviral vector containing IκBα superrepressor (Ad Iκ BSR) prevented the induction of c-IAP2 and XIAP in polyamine-deficient cells. Decreased levels of c-IAP2 and XIAP proteins by inactivation of NF-κB through Ad Iκ BSR infection or treatment with the specific inhibitor Smac also overcame the resistance of polyamine-depleted cells to apoptosis induced by the combination of tumor necrosis factor (TNF)-α and cycloheximide (CHX). Although polyamine depletion did not alter levels of procaspase-3 protein, it inhibited formation of the active caspase-3. Decreased levels of c-IAP2 and XIAP by Smac prevented the inhibitory effect of polyamine depletion on the cleavage of procaspase-3 to the active caspase-3. These results indicate that polyamine depletion increases expression of c-IAP2 and XIAP by activating NF-κB in intestinal epithelial cells. Increased c-IAP2 and XIAP after polyamine depletion induce the resistance to TNF-α/CHX-induced apoptosis, at least partially, through inhibition of the caspase-3 activity.
Mechanisms of caspase-1 activation by P2X7 receptor-mediated K+ release
Authors: Kahlenberg J. Michelle , Dubyak George R.
Published: April 2004

The mechanisms underlying caspase-1 activation and IL-1β processing during inflammatory activation of monocytes and macrophages are not well defined. Here, we describe an in vitro proteolytic processing assay that allows for comparison of caspase-1 regulatory components in a cell-free system separately from the confounding issue of IL-1β secretion. Analysis of in vitro IL-1β and caspase-1 processing in lysates from unstimulated Bac1 murine macrophages indicated a slow rate of basal caspase-1 activation and proteolytic maturation of IL-1β. In contrast, brief (5 min) treatment of intact macrophages with extracellular ATP (as an activator of the P2X7 receptor) or nigericin before cell lysis markedly accelerated the in vitro processing of caspase-1 and IL-1β. This acceleration of in vitro processing was strictly dependent on loss of intracellular K+ from the intact cells. The induction of in vitro caspase-1 activation by lysis per se or by K+ loss before lysis was sensitive to pretreatment of intact macrophages with the tyrphostin AG-126 or bromoenol lactone, an inhibitor of Ca2+-independent phospholipase A2. Caspase-1 activation and IL-1β processing in lysates from unstimulated macrophages were also accelerated by addition of recombinant ASC, a previously identified adapter protein that directly associates with caspase-1. These data indicate that increased K+ efflux via P2X7 nucleotide receptor stimulation activates AG-126- and bromoenol lactone-sensitive signaling pathways in murine macrophages that result in stably maintained signals for caspase-1 regulation in cell-free assays.
Alveolar macrophages are a primary barrier to pulmonary absorption of macromolecules
Authors: Lombry Catherine , Edwards David A. , Préat Véronique , Vanbever Rita
Published: April 2004

We demonstrate that a primary source of elimination of inhaled macromolecules after delivery to the lungs and before absorption into the systemic circulation owes to clearance by alveolar macrophages (AM). Depletion of AM by liposome-encapsulated dichloromethylene diphosphonate is shown to cause severalfold enhancement in systemic absorption of IgG and human chorionic gonadotropin after intratracheal instillation in rats. Lowering the doses of IgG delivered to the lungs alleviates local degradation and results in a dramatic increase in systemic absorption of the protein as well. Chemical and physical means of minimizing uptake of macromolecules by AM are proposed as novel methods for enhancing protein absorption from the lungs. Such strategies may have important ramifications on the development of inhalation as an attractive mode of administration of therapeutic proteins to the bloodstream.
Support functionals and their relation to the Radon‐Nikodym property
Authors: Sadeqi I.
Published: April 2004

In this paper, we examine the Radon‐Nikodym property and its relation to the Bishop‐Phelps theorem for complex Banach spaces. We also show that the Radon‐Nikodym property implies the Bishop‐Phelps property in the complex case.
On defining the product r−k · ∇lδ
Authors: Li C. K. , Zou V.
Published: April 2004

Let ρ(s) be a fixed infinitely differentiable function defined on R+ = [0, ∞) having the properties: (i) ρ(s) ≥ 0, (ii) ρ(s) = 0 for s ≥ 1, and (iii) where δn(x) = cmnmρ(n2r2) and cm is the constant satisfying (iii). We overcome difficulties arising from computing ∇lδn and express this regular sequence by two mutual recursions and use a Java swing program to evaluate corresponding coefficients. Hence, we are able to imply the distributional product r−k · ∇lδ for k = 1, 2, … and l = 0, 1, 2, … with the help of Pizetti′s formula and the normalization.
Eigenstructure of the equilateral triangle. Part III. The Robin problem
Authors: McCartin Brian J.
Published: April 2004

Lamé′s formulas for the eigenvalues and eigenfunctions of the Laplacian on an equilateral triangle under Dirichlet and Neumann boundary conditions are herein extended to the Robin boundary condition. They are shown to form a complete orthonormal system. Various properties of the spectrum and modal functions are explored.
Downhole seismic imaging of a massive sulfide orebody with mode‐converted waves, Halfmile lake, New Brunswick, Canada
Authors: Bellefleur Gilles , Müller Christof , Snyder David , Matthews Larry
Published: April 2004

Multioffset, multiazimuth downhole seismic data were acquired at Halfmile lake, New Brunswick, to image known massive sulfide lenses and to investigate the potential existence of a steeply dipping mineralized zone connecting them. The massive sulfide lenses, which have significantly higher elastic impedances than host rocks, produce strong scattering. The downhole seismic data show prominent scattered (P‐P and S‐S) and mode‐converted (P‐S and S‐P) waves originating from the deposit. Such complex scattering from massive sulfide ore was not observed previously in vertical seismic profiling data. Migration of the scattered and mode‐converted waves from several shot points imaged different parts of the deepest lens. The scattered S‐waves and mode‐converted waves provide additional imaging capabilities that should be considered when selecting downhole seismic methods for mining exploration.
VSP traveltime inversion: Near‐surface issues
Authors: Moret Geoff J.M. , Clement William P. , Knoll Michael D. , Barrash Warren
Published: April 2004

P‐wave velocity information obtained from vertical seismic profiles (VSPs) can be useful in imaging subsurface structure, either by directly detecting changes in the subsurface or as an aid to the interpretation of seismic reflection data. In the shallow subsurface, P‐wave velocity can change by nearly an order of magnitude over a short distance, so curved rays are needed to accurately model VSP traveltimes. We used a curved‐ray inversion to estimate the velocity profile and the discrepancy principle to estimate the data noise level and to choose the optimum regularization parameter. The curved‐ray routine performed better than a straight‐ray inversion for synthetic models containing high‐velocity contrasts. The application of the inversion to field data produced a velocity model that agreed well with prior information. These results show that curved‐ray inversion should be used to obtain velocity information from VSPs in the shallow subsurface.
Least‐squares inversion of in‐situ sonicQmeasurements: Stability and resolution
Authors: Dasios Aristotelis , McCann Clive , Astin Timothy
Published: April 2004

We minimize the effect of noise and increase both the reliability and the resolution of attenuation estimates obtained from multireceiver full‐waveform sonics. Multiple measurements of effective attenuation were generated from full‐waveform sonic data recorded by an eight‐receiver sonic tool in a gas‐bearing sandstone reservoir using two independent techniques: the logarithmic spectral ratio (LSR) and the instantaneous frequency (IF) method. After rejecting unstable estimates [receiver separation <2 ft (0.61 m)], least‐squares inversion was used to combine the multiple estimates into high‐resolution attenuation logs. The procedure was applied to raw attenuation data obtained with both the LSR and IF methods, and the resulting logs showed that the attenuation estimates obtained for the maximum receiver separation of 3.5 ft (1.07 m) provide a smoothed approximation of the high‐resolution measurements. The approximation is better for the IF method, with the normalized crosscorrelation factor between the low‐ and high‐resolution logs being 0.90 for the IF method and 0.88 for the LSR method.
Analyzing three‐component 3D vertical seismic profiling data
Authors: Gulati Jitendra S. , Stewart Robert R. , Parkin John M.
Published: April 2004

A three‐component 3D vertical seismic profile (VSP) was acquired over the Blackfoot oil field in Alberta, Canada. The VSP survey was recorded simultaneously with a surface seismic program. The objectives of the VSP were to develop recording logistics, data handling, and processing procedures and to determine if the 3D VSP volumes could image the glauconitic sand reservoir of the Blackfoot field.

Dynamite shots from the surface seismic survey, which fell within a 2200‐m offset from the recording well, were used in the VSP analysis. The shots were recorded by a string of three‐component borehole receivers that was moved seven times, resulting in a receiver depth range of 400 to 910 m. The borehole data were processed using basic VSP processing techniques that included hodogram analysis, wavefield separation using median filters, and VSP deconvolution. The final P‐P and P‐S image volumes were obtained by VSP common‐depth point and VSP common‐conversion point stacking the upgoing wavefields followed by f‐xy deconvolution. The P‐P and P‐S images from the VSP correlate well with those from the surface seismic survey. Time slices from the VSP also indicate the trend of the sand channel of the Blackfoot field.
Crosswell electromagnetic and seismic imaging: An examination of coincident surveys at a steam flood project
Authors: Hoversten G. Michael , Milligan Paul , Byun Joongmoo , Washbourne John , Knauer Larry C. , Harness Paul
Published: April 2004

We studied crosswell electromagnetic and seismic images of three oil‐saturated intervals within a southern California heavy oil field undergoing steam flood. The crosswell survey is located in a portion of the field where one well is in a “cold spot,” resulting in differing steam propagation within the three units. Log analysis shows linear or second‐order polynomial relationships (with correlation coefficients greater than 0.7) between electrical conductivity and water saturation, porosity, and clay content; whereas only a weakly linear relationship can be found between velocity and temperature in the lower unit studied. Crosswell seismic data is used to produce a velocity tomogram and a reflection section, and crosswell electromagnetic data is used to produce a conductivity section and derived porosity and water saturation. The seismic velocities from the tomograms show lateral variations consistent with the lateral variations in temperature seen in observation wells on either side of the crosswell section. The continuity and disruption of seismic reflections coincide with zones of continuous and variable porosity and water saturation as produced from the crosswell electromagnetic inverted conductivity section, and the derived regression fits between conductivity and porosity/water saturation. Seismic velocities, reflections, electrical conductivity, and the derived porosity and water saturation sections all contribute to explaining the observed lateral temperature variations between the wells within the three reservoir units. The unit with high steam content has low water saturation, high porosity, and laterally continuous low‐velocity and seismic reflections, consistent with no barriers to flow. The upper unit, where steam breaks through later in the experiment, also has high porosity and laterally continuous seismic reflections. However, it shows a velocity gradient between the hot and cold wells consistent with the lack of steam in the cold well at the time of the experiment. The middle unit, in which steam never reaches the cold well during the experiment, has the highest water saturation and the largest zone of reduced porosity and disrupted seismic reflections, indicating a possible barrierto flow.
Transient electromagnetic responses of 3D polarizable body
Authors: El‐Kaliouby Hesham M. , Eldiwany Essam A.
Published: April 2004

The transient voltage response of a central loop electromagnetic system above a buried polarizable parallelepiped target (such as pyrites, sulfides, clays, etc.) is studied. The voltage response, which includes a positive part and a negative part (related to the polarization properties), is studied by varying the body characteristics, including the Cole‐Cole parameters, body dimensions, depth, and thickness. By varying the loop radius and by using profiling, the lateral body dimensions can be identified, particularly using the negative response for polarizable bodies. There is a clear difference in the dependencies of the positive and negative voltage responses on the body characteristics, which means that the negative voltage is not just redundant data, but we may use it, together with the positive response, to have better understanding for the body dimensions and polarization parameters effects.
Attitude corrections of helicopter EM data using a superposed dipole model
Authors: Yin Changchun , Fraser Douglas C.
Published: April 2004

The analysis of helicopter‐borne electromagnetic (EM) survey data commonly assumes that the EM sensor (bird) has flown straight and levelly, whereupon the coils are either horizontal or vertical. The EM data typically are transformed, under this assumption, to yield the electrical properties (conductivity, permeability, permittivity) of a homogeneous earth, or they are inverted to a horizontally layered earth. In actual fact, the bird exhibits some roll, pitch, and yaw rotation, which will generate changes to the data that we call bird attitude effect.

On the basis of a superposed dipole model, we distinguish the geometric part of the bird attitude effect from the inductive part. Theoretical investigation shows that the geometric effect results from the reorientation of the bird's coil axes related to the earth. It is independent of the system frequency and the electrical properties of the earth but dependent only on the bird's attitude. In contrast, the inductive effect results from the coupling change between the coils and the conductive earth. It depends not only on the attitude of the bird but also on the system frequency and the earth's electrical properties.

We calculate ratios of the EM responses when the bird is rotated to those when the bird flies straight and levelly. These ratios, reflecting the purely geometric effect of the bird's rotation, are simple trigonometric functions of the rotation angles and thus can be easily incorporated into our processing of the EM data. We show that, in the general case of helicopter EM systems, the majority (>95%) of the attitude error results from the geometric effect rather than from the inductive effect. Sufficient accuracy is obtained by using the simple geometric technique for attitude correction, without requiring information about the earth's electrical properties. We demonstrate the usefulness of the method, using an example from a test survey.
Integrating S‐wave seismic‐reflection data and cone penetration test data using a multiangle multiscale approach
Authors: Ghose Ranajit , Goudswaard Jeroen
Published: April 2004

A cone penetration test (CPT) is the most common geotechnical testing method used to estimate in situ the strength properties of soil. Although CPT provides valuable information, this information is restricted to the location of the measurement. We propose a new concept to integrate shallow S‐wave reflection seismic data with CPT data in order to obtain laterally continuous subsoil information. In this vein, a valid quantitative means to relate seismic reflections to CPT data is a primary requirement. The approach proposed here is based on the characterization of the scaling behavior of the local fine‐scale S‐wave velocity information extracted from the seismic reflection data and the same behavior of the CPT cone resistance. The local velocity contrast information is extracted by linearized Zoeppritz inversion of the amplitude‐preserved prestack reflection data. We have formulated a multiscale analysis approach employing the continuous wavelet transform in order to quantitatively characterize the nature of change at an interface of the local S‐wave velocity contrast and the CPT cone resistance and to illuminate any relation between these two. The multiscale analysis estimates the singularity parameter α, which indicates the nature of the interfacial change.

The application of our method to the field data has uncovered a striking relation between the nature of variation of the local S‐wave velocity contrast and that of CPT cone resistance; otherwise, such a relation was not visible. Detailed analyses of two extensive field datasets have shown that the lateral fine‐scale variation of soil strength, as seen by CPT cone resistance, has a close resemblance with the variation of the local S‐wave velocity function as seen by angle‐dependent reflection measurements. This leads to a unique possibility to integrate two very different in‐situ measurements—reflection seismic and CPT—providing laterally continuous detailed information of the soil layer boundaries.
Seismic low‐frequency effects in monitoring fluid‐saturated reservoirs
Authors: Korneev Valeri A. , Goloshubin Gennady M. , Daley Thomas M. , Silin Dmitry B.
Published: April 2004

There is a complex relationship between seismic attributes, including the frequency dependence of reflections and fluid saturation in a reservoir. Observations in both laboratory and field data indicate that reflections from a fluid‐saturated layer have an increased amplitude and delayed traveltime at low frequencies, when compared with reflections from a gas‐saturated layer. Comparison of laboratory‐modeling results with a diffusive‐viscous‐theory model show that low (<5) values of the quality factor Q can explain the observations of frequency dependence. At the field scale, conventional processing of time‐lapse VSP data found minimal changes in seismic response of a gas‐storage reservoir when the reservoir fluid changed from gas to water. Low‐frequency analysis found significant seismic‐reflection‐attribute variation in the range of 15–50 Hz. The field observations agree with effects seen in laboratory data and predicted by the diffusive‐viscous theory. One explanation is that very low values of Q are the result of internal diffusive losses caused by fluid flow. This explanation needs further theoretical investigation. The frequency‐dependent amplitude and phase‐reflection properties presented in this paper can be used for detecting and monitoring fluid‐saturated layers.
Incorporating geologic information into reflection tomography
Authors: Clapp Robert G. , Biondi Biondo L. , Claerbout Jon F.
Published: April 2004

In areas of complex geology, prestack depth migration is often necessary if we are to produce an accurate image of the subsurface. Prestack depth migration requires an accurate interval velocity model. With few exceptions, the subsurface velocities are not known beforehand and should be estimated. When the velocity structure is complex, with significant lateral variations, reflection‐tomography methods are often an effective tool for improving the velocity estimate. Unfortunately, reflection tomography often converges slowly, to a model that is geologically unreasonable, or it does not converge at all. The large null space of reflection‐tomography problems often forces us to add a sparse parameterization of the model and/or regularization criteria to the estimation. Standard tomography schemes tend to create isotropic features in velocity models that are inconsistent with geology. These isotropic features result, in large part, from using symmetric regularization operators or from choosing a poor model parameterization. If we replace the symmetric operators with nonstationary operators that tend to spread information along structural dips, the tomography will produce velocity models that are geologically more reasonable. In addition, by forming the operators in helical 1D space and performing polynomial division, we apply the inverse of these space‐varying anisotropic operators. The inverse operators can be used as a preconditioner to a standard tomography problem, thereby significantly improving the speed of convergence compared with the typical regularized inversion problem. Results from 2D synthetic and 2D field data are shown. In each case, the velocity obtained improves the focusing of the migrated image.
Multiple prediction through inversion: A fully data‐driven concept for surface‐related multiple attenuation
Authors: Wang Yanghua
Published: April 2004

This paper introduces a fully data‐driven concept, multiple prediction through inversion (MPI), for surface‐related multiple attenuation (SMA). It builds the multiple model not by spatial convolution, as in a conventional SMA, but by updating the attenuated multiple wavefield in the previous iteration to generate a multiple prediction for the new iteration, as is usually the case in an iterative inverse problem. Because MPI does not use spatial convolution, it is able to minimize the edge effect that appears in conventional SMA multiple prediction and to eliminate the need to synthesize near‐offset traces, required by a conventional scheme, so that it can deal with a seismic data set with missing near‐offset traces. The MPI concept also eliminates the need for an explicit surface operator, which is required by conventional SMA and is comprised of the inverse source signature and other effects. This method accounts implicitly for the spatial variation of the surface operator in multiple‐model building and attempts to predict multiples which are not only accurate kinematically but are also accurate in phase and amplitude.
Numerical analysis of the azimuth moveout operator for vertically inhomogeneous media
Authors: Alkhalifah Tariq T. , Biondi Biondo L.
Published: April 2004

The azimuth‐moveout (AMO) operator, unlike the dip‐moveout (DMO) operator, has a 3D structure in homogeneous isotropic media, with an out‐of‐plane (crossline) component. In general, this component is concave downward, giving the operator an overall skewed‐saddle shape. The AMO operator, necessary for azimuth correction only, is typically smaller in size than conventional DMO operators, which corresponds to purely offset correction to zero offset. When velocity varies vertically, the operator shape changes depending on the degree of velocity variation. The general shape of the operator, however, remains saddlelike. In fact, for smooth velocity increases with depth, similar to those found in the Gulf of Mexico, the v(z) AMO operator does not differ much from its homogeneous counterpart. In this case, the residual AMO operator, constructed by cascading a forward homogeneous AMO operator with an inverse v(z) one, is extremely small, which suggests that the impact of such v(z) variations on the AMO operator is generally small. Complex vertical velocity variations, on the other hand, result in more complicated AMO operators that include, among other things, triplications at moderate angles. Regardless of the complexity of the model, the v(z) operator has the same first‐order behavior as its homogeneous counterpart. As a result, for small dip angles the homogeneous AMO, as a tool for partial stacking, often enhances the image. Moderate to steep dips in complex v(z) media requires the application of an algorithm that honors such velocity variations.
Kinematic artifacts in prestack depth migration
Authors: Stolk Christiaan C. , Symes William W.
Published: April 2004

Strong refraction of waves in the migration velocity model introduces kinematic artifacts—coherent events not corresponding to actual reflectors—into the image volumes produced by prestack depth migration applied to individual data bins. Because individual bins are migrated independently, the migration has no access to the bin component of slowness. This loss of slowness information permits events to migrate along multiple incident‐reflected ray pairs, thus introducing spurious coherent events into the image volume. This pathology occurs for all common binning strategies, including common‐source, common‐offset, and common‐scattering angle. Since the artifacts move out with bin parameter, their effect on the final stacked image is minimal, provided that the migration velocity model is kinematically correct. However, common‐image gathers may exhibit energetic primary events with substantial residual moveout, even with the kinematically accurate migration velocity model.
Naming Concepts Worth Naming
Authors: Brown Rex
Published: April 2004

Useful decision aiding needs the analyst to communicate more effectively with the decision maker (more than with the typically less busy and more technical agent who hires the analyst). Howard (2004) makes some important contributions, but some of his terms, and his rejection of concepts he considers not worth naming, are questionable. I offer my own preferred terms for an expanded list of key decision-aiding concepts.
Communicating About Decisions
Authors: Keeney Ralph L.
Published: April 2004

Clear communication is important for making good decisions and for teaching people how to make better decisions. Decision analysts have special concepts with terms unfamiliar to most decision makers. Hence, in communicating about decisions, it is necessary to clarify and agree on usage of terms and often use terms familiar to decision makers to describe our concepts.
A Polyhedral Approach for the Staff Rostering Problem
Authors: Felici Giovanni , Gentile Claudio
Published: April 2004

In this paper we formulate and efficiently solve staff scheduling problems for large organizations that provide continuous services to customers. We describe an integer programming approach for a class of such problems, where solutions have to obey a number of constraints related to workload balancing, shift compatibility, and distribution of days off. The formulation of the constraints is general and can be extended to different personnel management problems where staff members must cover shifts, and management must assign a fixed number of days off per week. The model maximizes staff satisfaction, expressed by positive weights for pairs of shifts in consecutive days. We consider the associated polytope and study its structure, determining some classes of inequalities that are facet inducing for special subproblems and other valid classes. We also identify a particular subproblem whose solution can be used to determine strong cuts for the complete problem. In addition, we design special branching rules that break the symmetries that arise in the solution space and have a large impact in the efficiency of the method. The validity of this approach has been ascertained by extensive computational tests; moreover, the operations research (OR) department of an airline has implemented the method to solve ground staff management problems.
Productivity Effects of Organizational Change: Microeconometric Evidence
Authors: Bertschek Irene , Kaiser Ulrich
Published: April 2004

This paper analyzes the relationship between investment in information and communication technologies (ICT), non-ICT investment, labor productivity, and workplace reorganization. Firms are assumed to reorganize workplaces if the productivity gains arising from workplace reorganization exceed the associated reorganization costs. Two different types of organizational change are considered: enhancement group work and flattening of hierarchies. Empirical evidence is provided for a sample of 411 firms from the German business-related services sector.

We develop and estimate a model for labor productivity and firms' decision to reorganize workplaces that allows workplace reorganization to affect any parameter of the labor productivity equation. Our general and flexible methodology allows us to properly take account of strategic complementarities between the input factors and workplace reorganization. The estimation results show that changes in human resources practices do not significantly affect firms' output elasticities with respect to ICT, non-ICT capital, and labor, although most of the point estimates of the individual output elasticities and of the control variables for observable firm heterogeneity are larger if workplace reorganization is realized. We therefore apply the Kernel density-estimation technique and demonstrate that for firms with organizational change, the entire labor productivity distribution shifts significantly out to the right if workplace reorganization takes place, indicating that workplace reorganization induces an increase in labor productivity that is attributable to complementarities between the various input factors and workplace reorganization. By contrast, firms without organizational change would not have realized significant productivity gains if they had reorganized workplaces.
Analysis and Optimization of a Multistage Inventory-Queue System
Authors: Liu Liming , Liu Xiaoming , Yao David D.
Published: April 2004

An important issue in the management of supply chains and manufacturing systems is to control inventory costs at different locations throughout the system while satisfying an end-customer service-level requirement. The challenge involved is to solve a nonlinear constrained optimization problem that captures the key dynamics of a complex production-inventory system. In this paper, we first develop a multistage inventory-queue model and a job-queue decomposition approach that evaluates the performance of serial manufacturing and supply systems with inventory control at every stage. We then present an efficient procedure to minimize the overall inventory in the system while meeting the required service level. Our technique is relatively simple and delivers accurate performance estimates. Furthermore, numerical studies generate certain managerial insights into related design and control issues.
Suckers Are Born but Markets Are Made: Individual Rationality, Arbitrage, and Market Efficiency on an Electronic Futures Market
Authors: Oliven Kenneth , Rietz Thomas A.
Published: April 2004

The Iowa Electronic Markets are specially designed futures markets that appear to aggregate information efficiently to predict events such as election outcomes. Yet, in theory, perfect information aggregation is impossible. Further, the markets are populated by a nonrepresentative sample of mistake-prone and biased traders. That is, traders are prone to the behavioral anomalies predicted by behavioral finance. How can this be reconciled with market efficiency? Here, we take a first step by analyzing the behavior of two self-selected types of traders. Dramatic differences in mistake rates across traders can help us answer the question. Market-making traders who set prices are less mistake prone and appear to be more rational than price-taking traders. This highlights an important feature of markets: marginal (in this case, market making), not average, traders set prices. This can drive the efficiency of market prices in spite of large numbers of traders who display patently suboptimal behavior.
Design, Synthesis, and Biological Evaluation of Aminoboronic Acids as Growth‐Factor Receptor Inhibitors of EGFR and VEGFR‐1 Tyrosine Kinases
Authors: Asano Toru , Nakamura Hiroyuki , Uehara Yoshimasa , Yamamoto Yoshinori
Published: April 2004

A series of aminoboronic acids was synthesized based on the structure of lavendustin pharmacophore 1. Their inhibitory activities against the epidermal growth‐factor receptor (EGFR) and vascular endothelial growth‐factor receptor‐1 (VEGFR‐1, Flt‐1) protein tyrosine kinases, and various protein kinases, PKA, PKC, PTK, and eEF2K were evaluated. Selective inhibition activities were observed in a series of aminoboronic acids. 4‐Methoxy‐3‐((2‐ methoxyphenylamino)methyl)phenylboronic acid 10 inhibited EGFR tyrosine kinase, whereas 4‐(2,5‐dihydroxybenzylamino)phenylboronic acid 12 inhibited Flt‐1 protein kinase, although lavendustin pharmacophore 1 inhibited both EGFR and Flt‐1 kinases at a compound concentration of 1.0 μg mL−1. The selective inhibition of EGFR by 10 is considered to be due to the substitution of the dihydroxy groups on the benzyl moiety for a boronic acid group at the para position, whereas the selective inhibition of Flt‐1 by 12 is due to the substitution of the carboxyl group on the aniline moiety in the lavendustin pharmacophore 1 for a boronic acid group.
Exploring Recombinant Flavonoid Biosynthesis in Metabolically Engineered Escherichia coli
Authors: Watts Kevin T. , Lee Pyung Cheon , Schmidt‐Dannert Claudia
Published: April 2004

Flavonoids are important plant‐specific secondary metabolites synthesized from 4‐coumaroyl coenzyme A (CoA), derived from the general phenylpropanoid pathway, and three malonyl‐CoAs. The synthesis involves a plant type III polyketide synthase, chalcone synthase. We report the cloning and coexpression in Escherichia coli of phenylalanine ammonia lyase, cinnamate‐4‐hydroxylase, 4‐coumarate:CoA ligase, and chalcone synthase from the model plant Arabidopsis thaliana. Simultaneous expression of all four genes resulted in a blockage after the first enzymatic step caused by the presence of nonfunctional cinnamate‐4‐hydroxylase. To overcome this problem we fed exogenous 4‐coumaric acid to induced cultures. We observed high‐level production of the flavanone naringenin as a result. We were also able to produce phloretin by feeding cultures with 3‐(4‐hydroxyphenyl)propionic acid. Feeding with ferulic or caffeic acid did not yield the corresponding flavanones. We have also cloned and partially characterized a new tyrosine ammonia lyase from Rhodobacter sphaeroides. Tyrosine ammonia lyase was substituted for phenylalanine ammonia lyase and cinnamate‐4‐hydroxylase in our E. coli clones and three different growth media were tested. After 48 h induction, high‐level production (20.8 mg L−1) of naringenin in metabolically engineered E. coli was observed for the first time.
Synthesis of Metal‐Carbonyl–Dendrimer–Antibody Immunoconjugates: Towards a New Format for Carbonyl Metallo Immunoassay
Authors: Fischer‐Durand Nathalie , Salmain Michèle , Rudolf Bogna , Vessières Anne , Zakrzewski Janusz , Jaouen Gérard
Published: April 2004

We report the preparation of metal‐carbonyl–dendrimer–antibody conjugates. These metal‐carbonyl‐multilabeled antibodies are designed to be used in a new solid‐phase‐format carbonyl metallo immunoassay (CMIA). A fourth‐generation polyamidoamine dendrimer was labeled with 10–25 (η5‐cyclopentadienyl)iron dicarbonyl (η1‐N‐succinimidyl) entities. An antibody was chemically modified at its carbohydrate chains by a site‐directed process used to preserve the antigen–antibody binding site. The antibody was then coupled with the dendrimer labeled with 10 metal carbonyl groups. An average of 1.4 labeled dendrimers were grafted per antibody molecule. These metal‐carbonyl–dendrimer–antibody conjugates were used as new universal detection reagents that recognize their specific antigens. The antigens were spotted onto nitrocellulose membranes and detected by using the conjugates in combination with Fourier transform infrared spectroscopy. A detection level in the range 5–200 pmol per membrane was achieved. This approach opens the way to a new CMIA format.
Selective Inhibition of HIV‐1 Reverse Transcriptase (HIV‐1 RT) RNase H by Small RNA Hairpins and Dumbbells
Authors: Hannoush Rami N. , Carriero Sandra , Min Kyung‐Lyum , Damha Masad J.
Published: April 2004

We present here the design of a novel class of RNA inhibitors of the RNase H domain of HIV‐1 RT, a ribonuclease activity that is essential for viral replication in vivo. Specifically, we show that small RNA hairpins and dumbbells can selectively inhibit the RNase H activity of HIV‐1 RT without affecting other cellular RNases H (e.g., E. coli and human RNase H). These results suggest that the inhibitors do not interact with the nucleic acid binding site of RT RNase H, as this region should be well conserved among the various enzymes. The most potent inhibitors displayed IC50 values in the 3–8 μM range. Remarkably, the DNA polymerase activity, an intrinsic property of HIV RT, was not inhibited by the hairpin and dumbbell aptamers, a property not previously observed for any nucleic acid aptamer directed against RT RNase H. The results described here suggest a noncompetitive binding mechanism, as outlined in the differential inhibitory characteristics of each of the nucleic acid aptamers against the bacterial, human, and viral RNase H homologues.
Intermingling versus clonal coherence during skeletal muscle development: Mosaicism in eGFP/nLacZ‐labeled mouse chimeras
Authors: Eberhard Daniel , Jockusch Harald
Published: April 2004

To study the relative contributions of clonal coherence vs. myoblast intermingling to the formation of mammalian skeletal muscles, enhanced green fluorescent protein (eGFP) and nLacZ labels were used to analyze neonatal and adult mouse embryo aggregation chimeras. The eGFP marker allowed us to estimate absolute levels of the eGFP transgenic parental contributions as well as variances of levels within a chimeric individual; nLacZ served as a counter‐label in neonatal chimeras. In mature chimeric muscle, free intracellular diffusion of eGFP led to an averaging of the eGFP level in individual myofibers. Chimerism, i.e., differing eGFP levels, was evident between corresponding right and left muscles, between adjacent back, body wall, limb (shank, foot), and extraocular muscles and among myofibers within these muscles. Inhomogeneities in muscles far from their somitic origin indicated unbalanced sampling from small founder pools. The results obtained with adult eGFP↔0 chimeras were corroborated by neonatal chimeras with complementary eGFP↔nLacZ labels. Developmental Dynamics 230:69–78, 2004. © 2004 Wiley‐Liss, Inc.
3,11,19‐Trithia[3.3.3]pyridinophane: Structural Diversity in Its Transition Metal Complexes
Authors: Vetrichelvan Muthalagu , Lai Yee‐Hing , Mok Kum Fun
Published: April 2004

The pyridine‐containing aza‐thia macrocycle 3,11,19‐trithia[3.3.3]pyridinophane (10) and its complexes with NiII, PdII, CuI, AgI and HgII were synthesised and their crystal structures were determined. The NiII and HgII complexes (11, 12) are mononuclear with 10 serving as an unusual quinquedentate ligand. The CuI complex 13 is also mononuclear with 10 being tetra‐coordinated to a tetrahedral CuI. Palladium(II) forms a binuclear complex 14 which exists as an inorganic zwitterion and both PdII metal ions adopt the expected square‐planar geometry with facial coordination. Silver(I) forms one‐dimensional coordination polymers (15 and 16) with 10 and these exhibit two different coordination modes, namely tetrahedral and trigonal planar. It was found that the macrocycle 10 did not show any selectivity among a series of metal ions. The electronic and redox properties of several complexes were studied. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Investigations on the Reactivity of Bis(bromomagnesio)trimethylsilylmethane − Molecular Structure of a Tebbe‐Type Spiro‐Organomagnesium Compound
Authors: Hogenbirk Marijke , Schat Gerrit , de Kanter Franciscus J. J. , Akkerman Otto S. , Bickelhaupt Friedrich , Kooijman Huub , Spek Anthony L.
Published: April 2004

The reactivity of the 1,1‐di‐Grignard reagent Me3SiCH(MgBr)2(8) towards transition metal dihalides has been investigated. While most transformations were sluggish and gave no well‐defined products, the reaction of8with [Cp2ZrCl2] in a 1:1 ratio gave, in low yield, the novel spiro‐organomagnesium compound [Cp2ZrCHSiMe3(μ‐Br)]2Mg (12), which is stable at room temperature and does not disproportionate on addition of dioxane. An X‐ray crystal structure determination has shown that, in the solid state,12is present as theC2symmetric stereoisomer12a; it is sterically very crowded due to the trimethylsilyl substituents. Partial metalla‐alkene character is indicated by the short zirconium−carbon bonds, and agostic zirconium−hydrogen interactions by the short zirconium−hydrogen distances (Zr···H−C) and small1JC,Hcoupling constants. In benzene solution, equilibrium between12aand itsC1symmetric stereoisomer12bwas detected by1H and13C NMR spectroscopy. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Enzymatic Removal of Phenol and Chlorophenols Using Soybean Seed Hulls
Authors: Bassi A. , Geng Z. , Gijzen M.
Published: April 2004

Soybean peroxidase (SBP), (EC 1.11.1.7) can be readily extracted from soybean seed hulls. This study reports on the direct use of soybean seed‐hull extracts for the bioremediation of phenolic wastes. The crude SBP extract from the hulls, like pure soybean peroxidase, is catalytically active in a broad range of pH and temperatures. As SBP is gradually released into the aqueous solution from seed hulls, the direct use of soybean seed hulls can reduce SBP inactivation by H2O2 and enhance the utilization efficiency of SBP through the slow release of the enzyme from the seed hulls. However, large doses of soybean seed hulls were found to be ineffective in phenol removal. Gradual additions of H2O2 in combination with the SBP released from the hulls were applied to optimize the bioremediation. Since the crude extract contains a mixture of multiple soybean proteins, soybean seed hull slurry required a higher concentration of H2O2 to remove the phenolic substrates than did the purified enzyme. Under the experimental conditions, 80 % of phenol (10.6 mM), 96 % of 2‐chlorophenol (3.9 mM), 95 % of 2,4‐dichlorophenol (3.1 mM), and 94 % of mixed phenol and chlorophenols were removed using soybean seed hulls in a single batch reactor. These results demonstrate that soybean seed hulls, compared to purified SBP, may be a more cost‐effective alternative in the enzymatic removal of phenolic compounds through polymerization reactions.
Improvements in the reliability and quality of unstructured hybrid mesh generation
Authors: Ito Yasushi , Nakahashi Kazuhiro
Published: April 2004

This paper presents a reliable and automated approach to the generation of unstructured hybrid grids comprised of tetrahedra, prisms and pyramids for high Reynolds number viscous flow simulations. To enhance robustness, the hybrid mesh generation process starts with the formation of an isotropic tetrahedral grid. Prismatic layers are then added on no‐slip walls fully automatically by obeying user‐specified boundary conditions and three parameters: the number of the layers, an initial layer thickness normal to the walls, and a stretching factor. Topological modifications to the original isotropic tetrahedral elements are prohibited during the layer generation process. The tetrahedral elements near no‐slip walls are shifted inward and the resulting gap between the tetrahedra and the walls is filled up with prismatic elements. To enhance the quality of the prismatic layers around sharp corners, two normals are evaluated for the marching process in these regions. The addition of prismatic elements is locally stopped if negative‐volume elements are created or not enough space is left. An angle‐based smoothing method ensures that the quality of the tetrahedral elements is retained for a reasonable computational cost. The method is demonstrated for two scaled experimental supersonic airplane models designed at the National Aerospace Laboratory of Japan (NAL). Numerical results are compared with wind tunnel experimental data. Copyright © 2004 John Wiley & Sons, Ltd.
Implicit WENO shock capturing scheme for unsteady flows. Application to one‐dimensional Euler equations
Authors: Cadiou A. , Tenaud C.
Published: April 2004

The unsteady numerical simulation of one‐dimensional shock waves is investigated using high‐order convective TVD and WENO schemes. Emphasis is put on the capability of existing explicit and implicit time discretization to capture the correct shock velocity. A new implicit solver is then proposed based on the WENO approach. This scheme is presented for one‐dimensional problems, but is easily extended to multi‐dimensional cases. The implicit WENO scheme is tested against the classical TVD schemes for the case of the shock tube and shock‐entropy wave interaction. Copyright © 2004 John Wiley & Sons, Ltd.
Effect of fermentation on the starch digestibility, resistant starch and some physicochemical properties of sorghum flour
Authors: Elkhalifa Abd Elmoneim O. , Schiffler Burkhard , Bernhard Rita
Published: April 2004

The effect of natural fermentation of Tabat sorghum cultivar (Sorghum bicolor L. Moench) at 37°C for up to 36 h on pH, titratable acidity, starch digestibility, resistant starch and total starch was studied. The pH of the fermenting dough decreased sharply with a concomitant increase in the titratable acidity. In vitro starch digestibility markedly increased as a result of fermentation, while resistant starch and total starch decreased. Results showed that iodine absorption capacity increased during fermentation. Fermented sorghum had more soluble starch and swelling power at 100°C than at 85°C.
Influence of vitamin B6 supplementation on polyunsaturated fatty acids concentration in serum and liver of rats fed a diet restricted in protein
Authors: Bertrandt Jerzy , Klos Anna , Debski Bogdan
Published: April 2004

The influence of vitamin B6 on fatty acids content in serum and liver of rats receiving low protein diets was studied. Addition of B6 decreased linoleic acid (LA) and increased α‐linolenic acid (ALA) and docosahexaenoic acid (DHA) in serum of rats fed a protein‐deficient diet (9% energy from proteins) for 3 months. Further restriction of dietary protein (4.5% of energy from protein) caused an increase of the DHA concentration and sum of polyunsaturated fatty acids (PUFAs). In the liver of undernourished rats significant changes of PUFA composition were noticed, although without any significant influence of vitamin B6.
Autoproteolysis rate of rainbow trout muscle proteins
Authors: Fik Mirosław , Surówka Krzysztof
Published: April 2004

Effect of some physicochemical agents (pH, temperature and incubation time) and iced storage of farmed rainbow trout (Oncorhynchus mykiss) on autoproteolysis of muscle proteins and quality (sensory assessment, instrumental texture, total bacterial counts) were determined. The results showed that the autoproteolysis rate proceeded with its highest intensity at pH 4.2 and temperature about 55°C. The rate of protein hydrolysis and protease activity, as well as microbial contamination, gradually increased with prolonged periods of iced storage of fish. Properly iced trout immediately after its evisceration was acceptable in quality for up to 10 days.