bluuebunny/crossref_metadata_2025 huggingface dataset:
Knowledge managing and knowledge management systems in inter‐organizational networks
Authors: Carlsson Sven A.
Published: July 2003

It is argued that the basic economic resource in the new economy is knowledge. An important source for competitive advantage in this economy is organizations' networks of external relationships. It is also argued that information and communication technologies (ICT) and Knowledge Management Systems (KMS) can play an important role in knowledge‐intensive processes and flows. This paper presents a conceptualization of strategic knowledge managing within the context of inter‐organizational networks. The conceptualization is based on the resource‐based, dynamic capability, and absorptive capability views as well as ideas from the ‘gift economy’. Three types of inter‐organizational networks for strategic knowledge managing are defined: (1) extra‐networks; (2) inter‐networks; and (3) open networks. The paper discusses knowledge managing in the three network types and illustrates how ICT and KMS can be used to enable and enhance knowledge managing in inter‐organizational networks—the core business process used for illustration is new product development. Copyright © 2003 John Wiley & Sons, Ltd.
Chain Connectivity and Conformational Variability of Polymers: Clues to an Adequate Thermodynamic Description of Their Solutions, 2
Authors: Wolf Bernhard A.
Published: July 2003

In Part 1 of this contribution we have reported how the Flory‐Huggins interaction parameterχcan be modeled as a function of chain length within the composition range of pair interaction between the macromolecules by means of the three parametersα,ζ, andλ. This contribution presents the extension of the approach to arbitrary volume fractions,φ, of the polymer and its application to published data onχ(φ). The resulting equation readsχ = α(1 − νφ)−2 − ζ(λ + 2(1 − λ)φ) and requires only the additional parameterνto incorporate the composition dependence. Its employment to experimental data is very much facilitated by substituting forχo(limiting value forφ → 0); furthermore, the expression can in good approximation be simplified toχ ≈ (χ0 + ζλ)(1 − νφ)−2 − ζλ(1 + 2φ). That is: only two parameters,νand the product ofζandλ, need to be adjusted. This relation is capable of describing all types of composition dependencies reported in the literature, including the hitherto incomprehensible occurrence of pronounced minima inχ(φ). For a given system the evaluation of the chain length dependence ofχo, reported in Part 1, and the present evaluation of the composition dependence ofχyield the same data for the conformational responseζ. Similarly both types of measurements generate the same interdependence betweenζandα. The physical meaning of the different parameters and the reason for the observed correlations are discussed.

Interrelation betweenζλandαfor the evaluated systems.

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Interrelation betweenζλandαfor the evaluated systems.
Supramolecular Branching and Crosslinking of Terpyridine‐Modified Copolymers: Complexation and Decomplexation Studies in Diluted Solution
Authors: Hofmeier Harald , Schubert Ulrich S.
Published: July 2003

A series of poly(methyl methacrylate) copolymers with terpyridine units in the side chains was obtained by free radical polymerization. The free terpyridine units were complexed by iron(II) and zinc(II) ions, and the complexation behavior was studied in detail, utilizing UV‐vis and viscosity titration experiments. Complexation of the polymer chains could be observed, which resulted in characteristic UV‐vis absorption bands and an increase in the solution viscosity. Addition of a strong competitive ligand (hydroxyethyl ethylenediaminetriacetic acid, HEEDTA) resulted in an efficient decomplexation.

UV‐vis spectra and photos of uncomplexed copolymer 2b before and after complexation with iron(II) ions (in chloroform) and after decomplexation with HEEDTA.

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UV‐vis spectra and photos of uncomplexed copolymer 2b before and after complexation with iron(II) ions (in chloroform) and after decomplexation with HEEDTA.
Catalytic Chain Transfer Copolymerization of Methyl Methacrylate and Butyl Acrylate
Authors: Pierik Sebastiaan C. J. , van Herk Alex M.
Published: July 2003

In this work it is shown that catalytic chain transfer is a very efficient way of controlling molecular weight in the copolymerization of methyl methacrylate (MMA) and butyl acrylate (BA). The experimental data are compared to a previously developed model based on copolymerization kinetics and the mechanisms for catalytic chain transfer and for cobalt‐mediated living radical polymerization that can describe the observed transfer constants. Secondly, it is shown that the presence of a catalytic chain transfer agent does not affect the reactivity ratios within the concentration range studied. Finally, the effect of conversion and therewith composition drift on the catalytic chain transfer polymerization of MMA and BA is investigated and it is shown that under the conditions employed in the experiments a certain degree of macromer copolymerization is present at high partial conversions of MMA.

Evolution of MWD with conversion for the CCT copolymerization of MMA and BA in toluene at 60 °C, [AIBN] = 6 × 10−3 mol · L−1.

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Evolution of MWD with conversion for the CCT copolymerization of MMA and BA in toluene at 60 °C, [AIBN] = 6 × 10−3 mol · L−1.
Macrocycles, 22
Authors: Kricheldorf Hans R. , Schwarz Gert , Böhme Sigrid , Schultz Claus‐Ludolf , Wehrmann Rolf
Published: July 2003

The phosgenation of bisphenol A with diphosgene in the CH2Cl2/NaOH system was studied using the pseudo‐high‐dilution method either with triethylamine, with triethylbenzyl ammonium chloride (TEBA‐Cl), or with tetraphenylphosphonium chloride as catalyst. For Ph4PCl, only low‐molecular‐weight polycarbonates containing various by‐products were obtained. With the TEBA catalyst, the fraction of cycles and the average molecular weights increased with higher feed ratios of the catalyst. Both the fraction of cycles and the molecular weights steeply decreased at higher temperatures. With triethylamine as catalyst both the fraction of cycles and molecular weight passed through a maximum at low catalyst concentration, when the feed ratio of triethylamine was varied. Higher temperatures favored slightly lower fractions of cycles and lower molecular weights. Samples containing ≥ 95 mol‐% of cycles were obtained. The cycles were identified by matrix‐assisted laser desorption ionization time‐of‐flight (MALDI‐TOF) mass spectrometry up to 22 000 Da in the case of virgin samples, and up to 55 000 Da after fractionation by size exclusion chromatography (SEC). Selected samples were characterized by SEC measurements and evaluated by the triple‐detection method. High polydispersities and a tendency towards a bimodal mass distribution were found, when triethylamine was used as catalyst.

MALDI‐TOF mass spectrum of a polycarbonate prepared by triethylamine‐catalyzed phosgenation at 20 °C by the pseudo‐high‐dilution method.

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MALDI‐TOF mass spectrum of a polycarbonate prepared by triethylamine‐catalyzed phosgenation at 20 °C by the pseudo‐high‐dilution method.
Quantitative Correlation between Steric Defects and Thermal Behavior in Highly Syndiotactic Polystyrene: A Study Based on DSC and 13C NMR Spectroscopy
Authors: Abbondanza Luigi , Abis Luigi , Cardi Nicoletta , Garbassi Fabio , Po Riccardo
Published: July 2003

Several syndiotactic polystyrene (sPS) samples have been synthesized by using different catalytic systems. Their stereochemistry has been determined by 13C NMR spectra in both the aliphatic CH2 and aromatic C1 resonance regions. The observed peaks have been unambiguously assigned to specific hexads and heptads, respectively, and their intensities have been used to draw the percent of defects (meso dyads) in the polymer chains. On the hypothesis that chain defects are at the origin of chain folding and thus determine the thickness of crystalline lamellae, we performed differential scanning calorimetry (DSC) analysis on the same samples, and their thermal parameters were measured. A model was developed to determine the amount of steric defects from the DSC melting‐peak profiles, and the results obtained were compared with the NMR results. A satisfactory agreement was found (correlation factor 0.96) in the explored range of defect concentrations (up to 2.5% of meso dyads). The possible influence of the extraction procedure of the amorphous fraction was found to be negligible. Thus, information on stereochemistry can be obtained from DSC experiments starting from as‐prepared (not extracted) samples.

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TLB: An Experienced Consultant and Broker between Universities and Industry
Authors: Dubs Andreas
Published: July 2003

This section contains news of the macromolecular community all over the world. Articles about, for example, people, projects, and market trends are welcome. Suggestions should be sent to the editorial office of the Macromolecular journals, preferably by E‐mail to macromol@wiley‐vch.de. The editorial office decides which articles will be published.
Semiclassical resolvent estimates for Schrödinger matrix operators with eigenvalues crossing
Authors: Jecko Thierry
Published: July 2003

For semiclassical Schrödinger 2×2–matrix operators, the symbol of which has crossing eigenvalues, we investigate the semiclassical Mourre theory to derive bounds O(h−1) (h being the semiclassical parameter) for the boundary values of the resolvent, viewed as bounded operator on weighted spaces. Under the non–trapping condition on the eigenvalues of the symbol and under a condition on its matricial structure, we obtain the desired bounds for codimension one crossings. For codimension two crossings, we show that a geometrical condition at the crossing must hold to get the existence of a global escape function, required by the usual semiclassical Mourre theory.
Ekeland's variational principle in locally complete spaces
Authors: Jing‐Hui Qiu
Published: July 2003

We extend Ekeland's variational principle to locally complete locally convex spaces. As an application of the extension, we obtain a drop theorem in locally convex spaces which improves the related known result.
On some new properties of the gamma function and the Riemann zeta function
Authors: Liao Liangwen , Yang Chung‐Chung
Published: July 2003

In this paper, we have exhibited, by utilizing value distribution theory, some new properties of the Gamma function Γ(z) and the Riemann zeta function ζ(z). Specifically, we have proved that both of the two functions are prime and the Riemann zeta function, like Γ(z), does not satisfy any algebraic differential equation with coefficients in ℒ︁0. Moreover, the two functions do not satisfy any functional equation of the form P(Γ, ζ, z) ≡ 0, where P(x, y, z) is a nonconstant polynomial in x, y and z.
Local solvability for semilinear Fuchsian equations
Authors: Messina Francesca
Published: July 2003

We consider a semilinear elliptic operator P on a manifold B with a conical singular point. We assume P is Fuchs type in the linear part and has a non–linear lower order therms. Using the Schauder fixed point theorem, we prove the local solvability of P near the conical point in the weighted Sobolev spaces.
On Osgood theorem in Banach spaces
Authors: Shkarin Stanislav
Published: July 2003

Let X be a real Banach space, ω : [0, +∞) → ℝ be an increasing continuous function such that ω(0) = 0 and ω(t + s) ≤ ω(t) + ω(s) for all t, s ∈ [0, +∞). According to the infinite dimensional analog of the Osgood theorem if ∫10 (ω(t))−1 dt = ∞, then for any (t0, x0) ∈ ℝ×X and any continuous map f : ℝ×X → X such that ∥f(t, x) – f(t, y)∥ ≤ ω(∥x – y∥) for all t ∈ ℝ, x, y ∈ X, the Cauchy problem $\dot x$(t) = f(t, x(t)), x(t0) = x0 has a unique solution in a neighborhood of t0. We prove that if X has a complemented subspace with an unconditional Schauder basis and ∫10 (ω(t))−1 dt < ∞ then there exists a continuous map f : ℝ × X → X such that ∥f(t, x) – f(t, y)∥ ≤ ω(∥x – y∥) for all (t, x, y) ∈ ℝ × X × X and the Cauchy problem $\dot x$(t) = f(t, x(t)), x(t0) = x0 has no solutions in any interval of the real line.
On the structure of the solution set of a third kind boundary value problem
Authors: Takahasi Sin–Ei , Oka Hirokazu , Miura Takeshi
Published: July 2003

We show that given any closed subset C of a real Banach space E, there is a continuous function f(t, x) which is Lipschitz continuous in its second variable such that the solution set of the corresponding third kind boundary value problem is homeomorphic to C (Theorem 1.1). In the special problem we give the infimum of Lipschitz constants Lf of such functions f(t, x) (Theorem 1.3).
A meta‐analytic investigation of contrast effects in decision making
Authors: Conway Dato‐on Mary , Dahlstrom Robert
Published: July 2003

Several theoretical perspectives and numerous experiments illustrate the influence of context on social judgment. Debate ensues, however, when researchers attempt to describe mechanisms that lead persons to contrast current decisions with prior judgments. The purpose of this study is to summarize and qualify prior analyses of the influences of context on judgment. Procedural conditions, stimuli type, and priming conditions are implicated as factors that moderate the main effect of extremity on contrastive judgments. Meta‐analytical methods assess the main effect and moderators of contrastive judgments. Discussion of the results focuses on the implications of the study for theory of contrastive judgments and strategy. © 2003 Wiley Periodicals, Inc.
Self‐assembly of metal‐organometallic coordination networks
Authors: Oh Moonhyun , Carpenter Gene B. , Sweigart Dwight A.
Published: July 2003

A range of neutral metal‐organometallic coordination networks (MOMNs) containing both backbone and pendant metal sites have been synthesized and characterized. These materials consist of metal ions or metal ion clusters as nodes that are linked by the bifunctional “organometalloligand” (η4‐benzoquinone)Mn(CO)3−, which binds through the quinone oxygen atoms. The resulting MOMNs can be rationally designed to a significant extent based upon a knowledge of the electronic and geometrical requirements of the metal ion nodes, the solvent, organometalloligand substituents, and the presence or absence of organic spacers. An impressive range of architectures have been accessed in this manner, suggesting that the use of π‐organometallics in coordination directed self‐assembly holds much promise.
Synthesis and thermal properties of diblock copolymers utilizing non‐covalent interactions
Authors: Lohmeijer Bas G.G. , Schlaad Helmut , Schubert Ulrich S.
Published: July 2003

Diblock copolymers of poly(styrene) and poly(ethylene oxide) were prepared utilizing a bisterpyridine ruthenium complex as non‐covalent interaction for the connection of the two blocks. Apart from the synthesis and characterization of four metallo‐supramolecular block copolymers, first studies on the thermal properties of the block copolymers have been performed. A complex crystallization behavior was observed and is described in a qualitative fashion. The influence of the metal complex on the thermal stability of the metallo‐supramolecular block copolymers remains a question for further investigation.
Precious metal polymers
Authors: Puddephatt Richard J.
Published: July 2003

The synthesis and properties of polymers containing precious metal centres in the backbone are described. Polymers with labile transition metal centres can be prepared by ring‐opening polymerization of macrocycles, and examples are given with silver, gold and palladium as the metal centres. In some cases, the polymers can be further organized by using ligands with hydrogen bonding substituents, and self‐assembly into sheet or network structures can then occur. Secondary bonding between inorganic centres can also lead to ordered self‐assembly. Bicyclic precursors can ring open to form either chains or sheets.
Design, synthesis and structural diversity in coordination polymers
Authors: Abourahma Heba , McManus Gregory J. , Moulton Brian , Bailey Walsh Rosa D. , Zaworotko Michael J.
Published: July 2003

The fundamental precept of crystal engineering is that all the information necessary for the design of a network is already stored in the molecular building blocks used. Coordination polymers represent an example of how crystal engineering has become a paradigm for the synthesis of new architectures and compositions. We report herein ten structures that are supramolecular isomers of one another. The structures are prepared from the same building blocks under mild reaction conditions. The modularity of coordination polymers imparts structural diversity that otherwise would not be possible.
Conformational analysis of siloxane‐based enzyme‐mimic precursors[1]
Authors: Parish Carol A. , Zeldin Martel , Hilson Sean , Pratt Jennifer
Published: July 2003

The conformational flexibility of six hybrid organodisiloxane oligomers were studied using the Low Mode‐Monte Carlo conformational search method with the MM2* force field and the Generalized Born/Surface Area continuum solvent model for water. These systems have enzyme‐like properties as synthetic acyltransferases and contain aminopyridine groups in various states of protonation. An ensemble of low energy structures was generated and used to investigate the dependence of molecular shape and flexibility on protonation, which plays an important role in catalyst solubility and self‐association. The results as measured by the number of unique conformations, end‐to‐end or longest intramolecular distance and radius of gyration of the conformational point cloud indicate that the number of protonated pyridines plays a significant role in the overall molecular shape. A similar study was also carried out on various POSS‐substitutive organodisiloxane oligomers.
Interactions of ferrocenoyl‐peptides in solution and on surfaces
Authors: Kraatz Heinz‐Bernhard
Published: July 2003

The Ferrocenoyl‐peptide‐cystamines, such as [Fc‐Gly‐CSA]2 (Gly = glycine, CSA = cystamine), [Fc‐Ala‐CSA]2 (Ala = alanine) and Fc‐conjugates involving collagen models, such as [Fc‐(Pro2Gly)n‐CSA]2 (Pro = proline, n = 1‐6) are readily prepared by solution methods. In solution and the solid state, these systems exhibit intermolecular hydrogen bonding between adjacent peptide chains. For [Fc‐Gly‐CSA]2 this results in the formation of a supramolecular helicate with two different H‐bonding patterns. Ferrocenoyl‐collagen‐cystamines form assemblies in solution, which melt at elevated tempertures. All systems for monolayers on gold surfaces, which show a well‐behaved ferrocene‐based electrochemistry, which allows the determination of the spatial requirements of the peptides on the surface.
Organoiron polymers containing azo dyes
Authors: Abd‐El‐Aziz Alaa S. , Todd Erin K. , Okasha Rawda M. , Afifi Tarek H.
Published: July 2003

The synthesis of cationic organoiron polymers with azobenzene moieties in their side chains has been accomplished via nucleophilic aromatic substitution and ring‐opening metathesis polymerization (ROMP) reactions. Polyaromatic ethers and thioethers with azobenzene moieties in their side chains were functionalized with different chromophores to yield yellow‐, orange‐ and red‐colored polymers. Polynorbornenes with azobenzene‐containing side chains were isolated following ROMP of their monomeric analogs. All of the organoiron polymers were soluble in polar organic solvents and underwent reversible electrochemical reduction processes. Photobleaching of the azobenzene‐containing polymers was achieved in the presence of hydrogen peroxide. The metallated polymers had glass transition temperatures approximately 50 to 80°C higher than their organic analogs.
Molecular Weight and Long Chain Branch Distributions of Branch‐Block Olefinic Thermoplastic Elastomers
Authors: Nele Márcio , Soares João B. P.
Published: July 2003

Olefinic thermoplastic elastomers can be prepared by incorporating semi‐crystalline macromonomers (e.g. isotactic or syndiotactic poly(propylene), high‐density polyethylene) onto amorphous backbones (e.g. atactic poly(propylene), ethylene/α‐olefin copolymers). The macromonomer incorporation reaction can be carried out in semi‐batch reactors by adding previously synthesized macromonomers to the reactor (ex situ approach), or by generating and incorporating the macromonomers in a single step (in situ approach). The differences in the microstructure of copolymers synthesized by in situ and ex situ techniques are explored herein through a mathematical model that can predict the concentration of linear and branched chains, their average molecular weights, polydispersity indices, and molecular weight distributions. In both cases linear chains predominate, but the ex situ approach produces a larger amount of branched chains with thermoplastic elastomer properties. Furthermore, for the in situ strategy, a significant amount of branched chains is only formed after the macromonomer concentration reaches a critical value.

Schematic representation of the polymerization mechanism.

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Schematic representation of the polymerization mechanism.
Pifithrin‐α promotes p53‐mediated apoptosis in JB6 cells
Authors: Kaji Akira , Zhang Yiguo , Nomura Masaaki , Bode Ann M. , Ma Wei‐Ya , She Qing‐Bai , Dong Zigang
Published: July 2003

Recently, blockage of p53‐dependent transcriptional activation and apoptosis by pifithrin‐α (PFTα) has been reported to be useful for reducing the side effects of cancer therapy and the compound is thus thought to be a specific inhibitor of p53 [Komarov et al., Science 1999;285:1733–1737]. Here, we found that PFTα did not inhibit UVB‐ or doxorubicin (Dox)‐stimulated p53‐mediated transcriptional activation and apoptosis in JB6 cells. Instead, p53‐dependent activation and apoptosis were not only induced by PFTα itself but were also enhanced by a combination of PFTα with UVB or Dox. Furthermore, PFTα‐induced apoptosis was mediated through p53‐dependent and ‐independent signaling pathways. Extracellular signal‐regulated kinases and p38 kinase, but not c‐jun N‐terminal kinases (JNKs), were activated, and these activations were required for phosphorylation and accumulation of p53 in the cellular apoptotic response to PFTα. Thus, we conclude that PFTα is not a specific p53 inhibitor in JB6 cells but is a potential activator of p53‐mediated signaling and apoptosis. © 2003 Wiley‐Liss, Inc.
Functional evaluation of novel single nucleotide polymorphisms and haplotypes in the promoter regions of CYP1B1 and CYP1A1 genes
Authors: Han Weiguo , Pentecost Brian T. , Spivack Simon D.
Published: July 2003

Interindividual variation in the expression of the carcinogen‐ and estrogen‐metabolizing enzymes cytochrome P4501B1 and 1A1 (CYP1B1 and CYP1A1) has been detected in human lung. To search for polymorphisms with functional consequences for CYP1B1 and CYP1A1 gene expression, we examined 1.5 kb of the promoter region of each gene. Genomic DNA from 21 Caucasian individuals was amplified by polymerase chain reaction (PCR) for direct cycle sequencing. Eight single nucleotide polymorphisms (SNPs) for CYP1B1 and 13 SNPs for CYP1A1 were found. The majority of polymorphisms occurred as multiSNP combinations for individual subjects. The wild‐type sequences were cloned into a luciferase reporter construct. The most frequent polymorphisms were then recreated by iterative site‐directed mutagenesis, replicating single polymorphisms and multiSNP combinations. These wild‐type and variant constructs were functionally evaluated in transient transfection experiments employing exposures to either the index polycyclic aromatic hydrocarbon (PAH) inducer benzo[a]pyrene (B[a]P), a composite mixture of cigarette smoke extract (CSE), or the repressor chemopreventive agent trans‐3,4,5‐trihydroxystilbene (reseveratrol). Results indicated that all wild‐type and variant constructs responded in qualitatively concordant fashion to the inducers and to the repressor. The CYP1B1 haplotypes and the majority of CYP1A1 haplotypes were shown to have no functional consequence, as compared to those of the wild‐type promoter sequences. Two constructs of composite polymorphisms of CYP1A1 appeared to result in a statistically significant increase in basal promoter activity (1.38‐ and 1.50‐fold, respectively), but the degree of functional impact was judged unlikely to be biologically important in vivo. We conclude that the observed promoter region polymorphisms in these genes are common, but are of unclear functional consequence. © 2003 Wiley‐Liss, Inc.
Translational regulation of a novel testis‐specific RNF4 transcript
Authors: Pero Raffaela , Lembo Francesca , Chieffi Paolo , Del Pozzo Giovanna , Fedele Monica , Fusco Alfredo , Bruni Carmelo B. , Chiariotti Lorenzo
Published: July 2003

The RING‐finger protein SNURF/RNF4, a modulator of both steroid receptor dependent and basal transcription, is expressed at very high levels in testis and at much lower levels in several other tissues. In somatic tissues, the RNF4 gene is expressed as a 3‐kb transcript while an additional shorter sized transcript (1.6 kb) was found in mouse testis. In murine germ cells, RNF4 protein expression is strongly modulated during progression of spermatogonia to spermatids, with a peak in spermatocytes. The expression of 3‐kb transcript correlated with protein levels in the different germ cell populations. Conversely, the 1.6‐kb transcript was abundantly and specifically expressed in spermatids, in which RNF4 protein was detected at very low levels. We have then examined possible mechanisms underlying this discrepancy. Primer extension and RNase protection analyses demonstrated that the 1.6‐ and 3.0‐kb transcripts originate from the same promoter, encode for the same protein and differ in the 3′ UTR. In vitro assays showed that protein degradation is not involved in the regulation of RNF4 protein level. Finally, polysome analysis revealed that only a slight fraction of the testis‐specific transcript is engaged in translation, thus providing a feasible mechanism for the quantitative differences of RNF4 mRNA and protein levels. Present results demonstrate that RNF4 short transcript is poorly translated suggesting that this mechanism could be essential for normal spermatogenesis. Mol. Reprod. Dev. 66: 1–7, 2003. © 2003 Wiley‐Liss, Inc.
Hmga1 is required for normal sperm development
Authors: Liu Jun , Schiltz John F. , Ashar Hena R. , Chada Kiran K.
Published: July 2003

The Hmgi protein family of chromosomal architectural factors is extensively studied for its roles in embryogenesis and its association with benign mesenchymal tumors. Although the biochemical function of Hmga1 has been studied in vitro, to provide in vivo insight into its biological function, a targeted disruption of Hmga1 was initiated. Chimeric founder mice were derived from embryonic stem (ES) cells harboring a targeted mutation in a single Hmga1 allele. These 14 different chimeric founders produced 494 black progeny. Since none of these 494 progeny were agouti, none of them were derived from ES cells. Control injections of the wild‐type ES cell lines resulted in ES cell derived agouti mice, indicating that the ES cells were totipotent. Therefore, our results indicate that one intact Hmga1 allele was not sufficient for germ‐line transmission of the ES cells. Seven chimeric founder mice that were examined histologically demonstrated aberrant regions in their reproductive organs. Aberrant regions of seminiferous tubules were reduced in diameter, demonstrated vacuolated Sertoli cells, and had an absolute deficiency of sperm. While the Hmga1+/− ES cells were shown to contribute to the formation of the epididymides, they did not significantly contribute to the testes of chimeric founder mice. No sperm isolated from any of the Hmga1+/− chimeric mice were shown to arise from the ES cells, as none of them contained the targeted disruption of the Hmga1 gene. Our results suggest that both alleles of Hmga1 are required for normal sperm production in the mouse. Mol. Reprod. Dev. 66: 81–89, 2003. © 2003 Wiley‐Liss, Inc.
Role of apoptosis and Fas/FasL system in the oogenesis of the spotted ray Torpedo marmorata
Authors: Loredana Ricchiari , Barbara D'onghia , Annamaria Liguoro , Stefania Tammaro , Maria Motta Chiara , Silvana Filosa , Piero Andreuccetti , Marina Prisco
Published: July 2003

In the present paper we investigated the role played by apoptosis during oogenesis in the cartilagineous fish Torpedo marmorata. TEM, TUNEL and immunohistochemical techniques were employed to specifically reveal morphological and biochemical hallmarks of apoptosis in specimens from birth to sexual maturity. Data obtained demonstrate that apoptosis occurs in prefollicular oocyte selection, in maintaining the homeostasis of granulosa in healthy growing oocyte and in resorbing atretic follicles. In this respect, the involvement of apoptosis in Torpedo marmorata oogenesis closely parallels that found in mammals, thus confirming that strategies of germ cell selection among vertebrates have been evolutively preserved. Mol. Reprod. Dev. 66: 54–59, 2003. © 2003 Wiley‐Liss, Inc.
Frequency of recombinant and nonrecombinant products of pericentric inversion of chromosome 1 in sperm nuclei of carrier: By FISH technique
Authors: Yakut Tahsin , Acar Hasan , Egeli Ünal , Kimya Yalçin
Published: July 2003

Meiotic segregation products of carriers with pericentric inversion are very important for assessing the risk of unbalanced forms and appropriate genetic counseling. We investigated the incidence of recombinant and nonrecombinant products of chromosome 1 with pericentric inversion, in the sperm nuclei of the carrier by using triple color fluorescence in situ hybridization (FISH). The centromere specific and telomere specific probes for chromosome 1 were used. In the segregation analysis, 1,636 sperm nuclei were analyzed; 82.5% of the sperms were including normal or inverted chromosome 1, and the dup(p)/del(q) and del(p)/dup(q) recombinant products in sperm nuclei of our carrier were 8.7 and 7.3%, respectively. The number of recombinant products may be dependent on the formation of an inversion loop, which the number of the formation of chiasmata results in the different number of normal/balanced and recombinant products. The use of FISH, using different probe combination, in sperm nuclei has proved to be an accurate approach to determine the meiotic segregation patterns and could help to better establish a reproductive prognosis and genetic counseling. Mol. Reprod. Dev. 66: 67–71, 2003. © 2003 Wiley‐Liss, Inc.
Glutamine and the maintenance of meiotic arrest in mouse oocytes: Influence of culture medium, glucose, and cumulus cells
Authors: Downs Stephen M. , Verhoeven Amelia
Published: July 2003

The selection of culture media and supplements therein has a tremendous impact on the regulation of oocyte maturation in vitro. In the present study, we have evaluated how altering the levels of glutamine in the presence or absence of glucose affects meiotic arrest in cumulus cell‐enclosed oocytes (CEO) and denuded oocytes (DO) when cultured in either the simple medium M16 or the more complex Eagle's minimum essential medium (MEM). We have also tested the effectiveness of follicle‐stimulating hormone (FSH) in triggering germinal vesicle breakdown (GVB) and purine de novo synthesis in differing MEM culture conditions. When DO were cultured 17–18 hr in hypoxanthine (HX)‐ or dbcAMP‐supplemented M16 medium, neither glucose nor glutamine had any effect on oocyte maturation, with dbcAMP the more effective inhibitor. In the absence of glutamine, cumulus cells promoted meiotic resumption, since significantly lower levels of meiotic arrest were maintained in CEO than in DO by either HX or dbcAMP, but addition of the amino acid dose‐dependently decreased the maturation percentage in CEO below that observed in DO. In MEM, glutamine and glucose again had little effect on the maturation of DO, although the percentage of maturing DO in HX‐supplemented medium was about 20% lower than that in M16 medium. In the absence of glucose, high levels of maturation were observed in CEO in glutamine‐free medium that were dose‐dependently lowered by the amino acid. However, when glucose was present, CEO were as effectively arrested as DO when glutamine was absent, with no further effect of the amino acid. This inhibitory action of glucose was dependent on the essential amino acids present in MEM. The effects of glutamine were not due to changes in metabolic coupling between the oocyte and cumulus cells. Measurement of purine de novo synthesis indicated that the maintenance of meiotic arrest as well as FSH induction of meiotic resumption were associated with increases in purine synthesis. We conclude that glucose and glutamine act cooperatively to promote the synthesis of new purine compounds within the somatic compartment and that the timing and duration of such synthesis determines whether meiotic resumption will be suppressed or promoted. Mol. Reprod. Dev. 66: 90–97, 2003. © 2003 Wiley‐Liss, Inc.
Cytochrome c oxidase of mammals contains a testes‐specific isoform of subunit VIb—the counterpart to testes‐specific cytochrome c?
Authors: Hüttemann Maik , Jaradat Saied , Grossman Lawrence I.
Published: July 2003

Sperm motility is highly dependent on aerobic energy metabolism, of which the apparent rate‐limiting step of the mitochondrial respiratory chain is catalyzed by cytochrome c oxidase (COX). COX is the only electron transport chain complex to display isoforms, consistent with its suggested rate‐limiting role. Isoforms were previously described for four of the 13 subunits. We now report the discovery that COX subunit VIb displays a testes‐specific isoform in human, bull, rat, and mouse (COX VIb‐2). Analysis of a variety of rat and mouse tissues, including ovaries, demonstrates exclusive expression of VIb‐2 in testes, whereas VIb‐1 transcripts are absent in rodent testes, even at early developmental stages. In contrast, both isoforms are transcribed in human testes. In situ hybridizations with human, rat, and mouse testes sections reveal VIb‐2 transcripts in all testicular cell types. Within the seminiferous tubules, VIb‐1 shows stronger signals in the periphery than in the lumen. Previously, cytochrome c was the only component of the mitochondrial respiratory chain known to express a testes‐specific isoform in mammals. COX subunit VIb connects the two COX monomers into the physiological dimeric form, and is the only COX subunit that, like cytochrome c, is solely located in the inter‐membrane space. Significant differences between the isoform sequences, in particular changes in charged amino acids, suggest interactions with cytochrome c and sperm‐specific energy requirements. Mol. Reprod. Dev. 66: 8–16, 2003. © 2003 Wiley‐Liss, Inc.
Improved developmental competence of cloned porcine embryos with different energy supplements and chemical activation
Authors: Lee Gab‐Sang , Kim Hye‐Soo , Hyun Sang‐Hwan , Kim Dae‐Young , Lee So‐Hyun , Nam Dong‐Hyun , Jeong Yeon‐Woo , Kim Sue , Kang Sung‐Keun , Lee Byeong‐Chun , Hwang Woo‐Suk
Published: July 2003

The present study investigated the effect of lactate/pyruvate supplement in culture medium and of chemical activation after electric stimulus on in vitro development of porcine somatic cell nuclear transfer (SCNT) embryos. In vitro matured gilt oocytes were enucleated, reconstructed with fetal fibroblasts, and simultaneously fused/activated using a single pulse of 2.0 kV/cm for 30 μsec. In Experiment 1, reconstructed embryos were cultured in North Carolina State University (NCSU)‐23 medium supplemented with either 5.5 mM glucose (Group A) or lactate (5.0 mM)/pyruvate (0.5 mM) (Group B). Compared to Group A, cleavage rate (64% vs. 47%) was higher and more blastocysts developed in Group B (17% vs. 6% at Day 6, 21% vs.11% at Day 7). Experiment 2, embryos reconstructed by electric stimulus (2.0 kV/cm for 30 μsec) were subjected to three activation protocols: (1) no chemical activation (Group C), (2) 7.5 μg/ml cytochalasin B treatment at 2 hr after electric stimulus (Group D), and (3) 5 μg/ml 6‐dimethylaminopurine (Group E) treatment at 2 hr after electric stimulus. The reconstructed embryos were cultured for 7 days in NCSU‐23 medium supplemented with lactate (5.0 mM)/pyruvate (0.5 mM). The rates of blastocyst formation on Day 6 and Day 7 in Group C (17 and 20%, respectively) or Group D (15, 20%, respectively) were higher than in Group E (9 and 12%, respectively). The percentage of two pseudo‐pronucleus (PPN) formations in Group D (88%) was significantly higher than in Group C (71%) and Group E (72%). Mean cell numbers of blastocysts in Group D (63.4 ± 15.8) were higher than in Group C (43.9 ± 16.5) and Group E (32.9 ± 17.9), due to increased trophectoderm (TE) cell numbers. Our results indicate that supplementing NCSU‐23 medium with lactate/pyruvate and exposure of cytochalasin B after electrical stimulus can improve in vitro developmental competence of porcine SCNT embryos. Mol. Reprod. Dev. 66: 17–23, 2003. © 2003 Wiley‐Liss, Inc.
Precise recapitulation of methylation change in early cloned embryos
Authors: Kang Yong‐Kook , Yeo Seungeun , Kim Seok‐Ho , Koo Deog‐Bon , Park Jung Sun , Wee Gabbine , Han Jee‐Soo , Oh Keon Bong , Lee Kyung‐Kwang , Han Yong‐Mahn
Published: July 2003

Change of DNA methylation during preimplantation development is very dynamic, which brings this term to the most attractive experimental target for measuring the capability of cloned embryo to reprogram its somatic genome. However, one weak point is that the preimplantation stage carries little information on genomic sequences showing a site‐specific re‐methylation after global demethylation; these sequences, if any, may serve as an advanced subject to test how exactly the reprogramming/programming process is recapitulated in early cloned embryos. Here, we report a unique DNA methylation change occurring at bovine neuropeptide galanin gene sequence. The galanin gene sequence in early bovine embryos derived by in vitro fertilization (IVF) maintained a undermethylated status till the morula stage. By the blastocyst, certain CpG sites became methylated specifically, which may be an epigenetic sign for the galanin gene to start a differentiation programme. The same sequence was moderately methylated in somatic donor cell and, after transplanted into an enucleated oocyte by nuclear transfer (NT), came rapidly demethylated to a completion, and then, at the blastocyst stage, re‐methylated at exactly the same CpG sites, as observed so in normal blastocysts. The precise recapitulation of normal methylation reprogramming and programming at the galanin gene sequence in bovine cloned embryos gives a cue for the potential of cloned embryo to superintend the epigenetic states of foreign genome, even after global demethylation. Mol. Reprod. Dev. 66: 32–37, 2003. © 2003 Wiley‐Liss, Inc.
Expression of angiogenesis‐ and apoptosis‐related genes in chorionic villi derived from recurrent pregnancy loss patients
Authors: Choi Hee‐Kyung , Choi Bum Chae , Lee Sook‐Hwan , Kim Jeong Wook , Cha Kwang Yul , Baek Kwang‐Hyun
Published: July 2003

Angiogenesis takes place during embryogenesis, characterized by the formation of new blood vessels from pre‐existing ones. This biological process is also found in the female reproductive system, wound healing, and cancer development. Apoptosis, programmed cell death, is a physiological process in development, tissue homeostasis, and disease. Apoptosis is a normal event in several reproductive tissues including human placenta. In these studies, we investigated whether aberrant angiogenesis and apoptosis are associated with recurrent pregnancy loss (RPL). We compared the gene expression level for angiogenesis‐ and apoptosis‐related genes in chorionic villi from RPL patients and those from normal controls. Semi‐quantitative reverse transcriptase‐polymerase chain reaction (RT‐PCR) analysis revealed that 7 angiogenesis‐ and 12 apoptosis‐related genes were abnormally expressed in chorionic villi from RPL patients. Angiogenesis‐related genes that showed aberrant expression level are matrix metalloproteinase‐2 (MMP‐2), plasminogen activator inhibitor (PAI), integrin, transforming growth factor‐β (TGF‐β), vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and leptin receptor. Expression levels for these genes, except for leptin receptor, showed less in chorionic villi from RPL patients than those from normal controls. In contrast, higher expression levels of 12 apoptosis‐related genes (caspase 3, 6, 7, 8, 9, 10, 12, BAD, BAX, BID, Fas, and FasL) were shown in chorionic villi from RPL patients than those from normal controls. Taken all together, it is likely that the lower expression of angiogenesis‐related genes and the excessive expression of apoptosis‐related genes are associated with RPL. Mol. Reprod. Dev. 66: 24–31, 2003. © 2003 Wiley‐Liss, Inc.
Mouse ICSI with frozen–thawed sperm: The impact of sperm freezing procedure and sperm donor strain
Authors: Moreira Pedro N. , Jimenéz Adela , Fernández Raul , Bury‐Madrid Ninoska , De La Fuente Julio , Pintado Belen , Gutiérrez‐Adán Alfonso
Published: July 2003

Normal mouse offspring can be obtained from oocytes injected with frozen–thawed spermatozoa without cryoprotection, however, embryo development can be affected by sperm freezing procedure and sperm donor strain. In this study we observed that direct contact of mouse spermatozoa with liquid nitrogen did not affect their ability to activate injected oocytes but severely restricted subsequent in vitro embryo development to blastocyst stage. Tris‐EDTA buffer and M2 were also shown to be better sperm freezing extenders than DPBS, allowing higher developmental potential. In addition, differences in embryo development obtained by intracytoplasmic sperm injection (ICSI) with frozen–thawed spermatozoa were observed between hybrid sperm donor strains. Frozen–thawed B6D2F1 spermatozoa provided higher embryo development than sperm cells from C57CBAF1. Mol. Reprod. Dev. 66: 98–103, 2003. © 2003 Wiley‐Liss, Inc.
Sensitivity curves for effective project management
Authors: Bowman R. Alan
Published: July 2003

A key problem in project management is to decide which activities are the most important to manage and how best to manage them. A considerable amount of literature has been devoted to assigning “importance” measures to activities to help with this important task. When activity times are modeled as random variables, these activity importance measures are more complex and difficult to use. A key problem with all existing measures is that they summarize the importance in a single number. The result is that it is difficult for managers to determine a range of times for an activity that might be acceptable or unacceptable. In this paper, we develop sensitivity curves that display the most useful measures of project performance (in terms of schedule) as a function of an activity's time. The structure of the networks allows us to efficiently estimate these curves for all desired activities, all desired time ranges, and all desired measures in a single set of simulation runs. The resulting curves provide insights that are not available when considering summarized measures alone. Chief among these insights is the ability to identify an acceptable range of times for an activity that will not lead to negative scheduling consequences. © 2003 Wiley Periodicals, Inc. Naval Research Logistics 50: 481–497, 2003
The cost impact of using simple forecasting techniques in a supply chain
Authors: Kim Heung‐Kyu , Ryan Jennifer K.
Published: July 2003

In this paper we consider an inventory model in which the retailer does not know the exact distribution of demand and thus must use some observed demand data to forecast demand. We present an extension of the basic newsvendor model that allows us to quantify the value of the observed demand data and the impact of suboptimal forecasting on the expected costs at the retailer. We demonstrate the approach through an example in which the retailer employs a commonly used forecasting technique, exponential smoothing. The model is also used to quantify the value of information and information sharing for a decoupled supply chain in which both the retailer and the manufacturer must forecast demand. © 2003 Wiley Periodicals, Inc. Naval Research Logistics 50: 388–411, 2003
Discretization of the continuous ambush game
Authors: Woodward I.D.
Published: July 2003

This article further considers the two‐person continuous ambush game introduced by Ruckle. This article extends the work of Ruckle, Baston and Bostock, and Lee by considering the game for a general number of barriers. By supplanting optimal strategies from a discretized version of the game, we show that there always exists a value for the game, which, furthermore, can be found using linear programming techniques. Further to this, we show that the discrete ambush game considered by Garnaev has the same value as a continuous game, allowing many new results to be obtained in both games. © 2003 Wiley Periodicals, Inc. Naval Research Logistics 50: 515–529, 2003
Analysis of a machine repair problem with an unreliable server and phase type repairs and services
Authors: Chakravarthy Srinivas R. , Agarwal Atul
Published: July 2003

In this paper we study a machine repair problem in which a single unreliable server maintains N identical machines. The breakdown times of the machines are assumed to follow an exponential distribution. The server is subject to failure and the failure times are exponentially distributed. The repair times of the machine and the service times of the repairman are assumed to be of phase type. Using matrix‐analytic methods, we perform steady state analysis of this model. The time spent by a failed machine in service and the total time in the repair facility are shown to be of phase type. Several performance measures are evaluated. An optimization problem to determine the number of machines to be assigned to the server that will maximize the expected total profit per unit time is discussed. An illustrative numerical example is presented. © 2003 Wiley Periodicals, Inc. Naval Research Logistics 50: 462–480, 2003
Simultaneous production of market‐specific and global products: A two‐stage stochastic program with additional demand after recourse
Authors: Cattani Kyle , Ferrer Geraldo , Gilland Wendell
Published: July 2003

This paper analyzes the simultaneous production of market‐specific products tailored to the needs of individual regions and a global product that could be sold in many regions. We assume that the global product costs more to manufacture, but allows the decision concerning the allocation of products to regions to be delayed until after the manufacturing process has been completed. We further assume that there is additional demand after the region allocation but prior to delivery, extending the two‐stage stochastic program with recourse to include additional stochastic demand after the recourse. This scenario arises, for example, when there is additional uncertainty during a delivery delay which might occur with transoceanic shipments. We develop conditions for optimality assuming a single build‐allocate‐deliver cycle and stochastic demand during both the build and deliver periods. The optimal policy calls for the simultaneous production of market‐specific and global products, even when the global product is substantially more costly than the market‐specific product. In addition, we develop bounds on the performance of the optimal policy for the multicycle problem. © 2003 Wiley Periodicals, Inc. Naval Research Logistics 50: 438–461, 2003