bluuebunny/crossref_metadata_2025_split huggingface dataset:
A generalization of a conservativity theorem for classical versus intuitionistic arithmetic
Authors: Berardi Stefano 
Published: January 2004

AbstractA basic result in intuitionism is Π02‐conservativity. Take any proof p in classical arithmetic of some Π02‐statement (some arithmetical statement ∀x.∃y.P(x, y), with P decidable). Then we may effectively turn p in some intuitionistic proof of the same statement. In a previous paper [1], we generalized this result: any classical proof p of an arithmetical statement ∀x.∃y.P(x, y), with P of degree k, may be effectively turned into some proof of the same statement, using Excluded Middle only over degree k formulas. When k = 0, we get the original conservativity result as particular case. This result was a by‐product of a semantical construction. J. Avigad of Carnegie Mellon University, found a short, direct syntactical derivation of the same result, using H. Friedman's A‐translation. His proof is included here with his permission. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Minima of initial segments of infinite sequences of reals
Authors: Hirst Jeffry L. 
Published: January 2004

AbstractSuppose that 〈xk〉k∈ℕ is a countable sequence of real numbers. Working in the usual subsystems for reverse mathematics, RCA0 suffices to prove the existence of a sequence of reals 〈uk〉k∈ℕ such that for each k, uk is the minimum of {x0, x1, …, xk}. However, if we wish to prove the existence of a sequence of integer indices of minima of initial segments of 〈xk〉k∈ℕ, the stronger subsystem WKL0 is required. Following the presentation of these reverse mathematics results, we will derive computability theoretic corollaries and use them to illustrate a distinction between computable analysis and constructive analysis. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The cumulative hierarchy and the constructible universe of ZFA
Authors: Viale Matteo 
Published: January 2004

AbstractWe present two results which shed some more light on the deep connection between ZFA and the standard ZF set theory: First of all we refine a result of Forti and Honsell (see [5]) in order to prove that the universe of ZFA can also be obtained (without appealing to choice) as the least fixed point of a continuous operator and not only as the greatest fixed point of the powerset operator. Next we show that it is possible to define a new absolute Gödel operation in addition to the standard ones in order to obtain the “constructible” model of ZFA as the least fixed point of the continuous operator of Gödel closure with respect to the standard and the new Gödel operations. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Corrigendum to “Kripke‐style semantics for many‐valued logics”
Authors: Montagna Franco , Sacchetti Lorenzo 
Published: January 2004

AbstractThis note contains a correct proof of the fact that the set of all first‐order formulas which are valid in all predicate Kripke frames for Hájek's many‐valued logic BL is not arithmetical. The result was claimed in [5], but the proof given there was incorrect. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Relationship between the distortion of polyene chains from planarity and the Raman activity of the in‐phase CH out‐of‐plane wag
Authors: Fujimori Kazuki , Sakamoto Akira , Tasumi Mitsuo 
Published: January 2004

AbstractThe relationship between the distortion of polyene chains from planarity and the Raman activity of the in‐phase CH out‐of‐plane wag is examined by performing density functional theory calculations. The vibrational wavenumbers, vibrational modes, Raman activities and infrared absorption intensities of several oligoene (or polyene) molecules are calculated for model structures having various kinds of distortion around the CC double and/or single bond(s). The results of calculations show that the molecular distortion induces the Raman activity of the in‐phase CH out‐of‐plane wag which should be Raman‐inactive for the planar structure. The Raman activity of the in‐phase CH out‐of‐plane wag is particularly enhanced when the molecule is uniformly helical. The origin of a weak Raman band at about 1010 cm−1 of trans‐polyacetylene is discussed on the basis of the calculated results.
Characterization of polypropylene (PP) nanocomposites for industrial applications
Authors: Korakianiti Athina , Papaefthimiou Vasiliki , Daflou Theofania , Kennou Stella , Gregoriou Vasilis G. 
Published: January 2004

AbstractThis study aims in the examination of a new class of materials named polymer layered silicate nanocomposites. In our case, composites are usually combinations of polypropylene matrix with solid mineral reinforcements named silicates (e,g. montmorillonite, a natural clay). In this study, two complementary techniques used to characterize nanocomposites. Fourier transform infrared spectroscopy (FT‐IR) both in transmission and attenuated total reflectance (ATR) modes combined with X‐ray photoelectron spectroscopy (XPS).
Deformation behavior of triblock copolymers based on polystyrene: an FT‐IR spectroscopy study
Authors: van Asselen O.L.J. , van Casteren I.A. , Goossens J.G.P. , Meijer H.E.H. 
Published: January 2004

AbstractThe effect of the long range order and thermal treatment on the micromechanical deformation of two triblock copolymers was investigated, i.e. polystyrene‐b‐polybutadiene‐b‐polycaprolactone (SBC) triblock copolymer with PS as the matrix and PCL cylindrical domains and a SBS triblock copolymers with 75 wt% of styrene. FTIR spectroscopy revealed information about the molecular orientation upon deformation of the separate components in the triblock copolymers. Films of SBC possess a higher ductility when the semi‐crystalline PCL cylindrical microdomains are quenched. In this case, the deformation proceeds via cavitation of the PCL domains and subsequent shear yielding. Long range order of the cylinders leads to embrittlement since crazes formation and crack propagation can proceed along the cylindrical axis. For the SBS triblock copolymers, a morphological transition from lamellar to short rod cylindrical microdomains was obtained by changing the casting solvent from toluene to MEK, while macroscopic orientation could be achieved by compression molding in a channel die. The toluene cast films were ductile and deformed in a homogeneous way. The MEK cast films behaved brittle as a result of crazing. Loading parallel to the lamellae results in yielding by propagation of a stable macroscopic neck.
A spectroscopic ellipsometry study of PET membranes from IR to Vis‐FUV
Authors: Laskarakis A. , Gioti M. , Pavlopoulou E. , Poulakis N. , Logothetidis S. 
Published: January 2004

AbstractA detailed study of Spectroscopic Ellipsometry (SE) spectra of uniaxially stressed, 12μm thick poly(ethylene terephthalate) (PET) membranes were realized in both IR (900‐3500 cm−1) and Vis‐FUV (1.5 to 6.5 eV) spectral regions and in various orientation angles ∅︁ between the plane of incidence and the machine direction (MD) of the PET membranes. In the IR spectra, the three main modes of the ester group at ∼1126, 1256 and 1721 cm−1 are observed. The first two of these peaks show identical polarization dependence, with preferential orientation ∅︁≈0° (i.e. the plane of reflection parallel to the MD), while the peak at ∼1721 cm−1 is excited in the perpendicular direction, ∅︁≈90°. In the Vis‐FUV SE spectra, the dependence of the characteristic electronic absorption bands on the orientation angle ∅︁ is studied. Besides the well known benzene band centered at ∼5 eV, a doublet of less intense peaks appear just above the absorption edge between 4.1 and 4.3 eV with the most striking characteristic that they show polarization selection rules opposing to that of the benzene band. The above characteristics of the electronic Vis‐FUV spectra of PET are discussed in a manner comparative to the corresponding IR spectra. The discussion becomes in the context of determining the molecular orientation of PET using a non‐destructive technique such as SE.
Spectroscopic characterization of micro‐phase separated blends of polystyrene/polymethyl methacrylate (PS/PMMA)
Authors: Korakianiti Athina , Walsh Siobhan , Gregoriou Vasilis G. 
Published: January 2004

AbstractAn investigation of the miscibility behaviour in polystyrene/ polymethyl methacrylate (PS/PMMA) blends of various compositions under different evaporations protocols using Fourier transform infrared (FT‐IR) and Raman Spectroscopic techniques took place in the study. Solvent selection and evaporation rates, coupled with variations in the blend composition resulted in completely different miscibility behaviour for these systems. In particular, it was found that blends with low PMMA content result in systems that exhibit PMMA domains of less than 7 microns on average. Finally, depth profiling studies of the PMMA moiety in the PS matrix show that the distribution of the low content phase is highly affected by the solvent selection as well as the blend composition.
Spectroscopic linear dichroism FT‐IR studies of synthetic spider silk
Authors: Koc Y. , Hammond P.T. , Lendl B. , Gregoriou V.G. 
Published: January 2004

AbstractThis work deals with the analysis of the orientation behavior of different segments of synthetic spider silk samples containing hard and soft segments. Two different types of spider silk were examined, one with an aliphatic hard segment (hexamethylene‐diisocyanate) and an amorphous soft segment (polytetramethylene oxide) (A40) and the other with an aromatic hard segment (4,4′‐methylene bisphenyl diisocyanate) and a semicrystalline soft segment (polyethylene oxide‐polypropylene oxide‐ polyethylene oxide) (A143). In order to observe the orientation behavior of the hard and the soft segments it was necessary to define marker bands. While for both samples the chosen marker bands for the hard segments were the same, the marker bands for the soft segments were different. FT‐IR spectra were recorded while strain was applied to the material at the same time. Two parameters, the dichroic ratio R and the order Parameter f were used to evaluate the behavior of these materials under conditions of strain. It was found that sample A143 broke at a strain level of 37,5 %, while sample A40 showed a high dynamic range up to a strain level of 307 %.
Fluorescence study of peptide and protein containing interpolyelectrolyte complexes
Authors: Mustafaev Mamed 
Published: January 2004

AbstractFour polyelectrolyte (PE)‐protein and PE‐peptide systems were selected for fluorescence experiments. The mode of binding of proteins to PE and structure of forming polycomplexes depends upon the ratio of components and chemical composition of polymer macromolecules. Complex formation of proteins with oppositely charged polycations is realized by the self‐assembly of non‐stoichiometric polycomplex particles with characteristic composition. These polycomplex particles have a rigid rod‐like carcass structures in which protein molecules are practically exposed to the solvent.Two types of ternary polyanion‐Cu2+‐protein polycomplex particles are formed depending on the monomer composition of the copolymer. At higher content of hydrophobic N‐isopropylacrylamide monomer unites, the protein globules in the structure of ternary polycomplex particles are densely covered by the shell of a polymer coil and practically “fenced of” from the water environment. At higher content of acrylic acid unites, polycomplex particles have more friable structures in which protein molecules are practically exposed to the solution.The PE‐peptide conjugate species can be represented rather as a macromolecule of a segmented (block) copolymer in which the hydrophobic blocks, i.e. the sequences of copolymer and peptide unit pairs, which have formed the covalent and salt bonds alternate with hydrophilic ones, i.e. the sequences of the copolymer chain not participating in the formation of double strand blocks.
Relationship between the coil‐globule transition of an aqueous poly(N‐isopropylacrylamide) solution and structural changes in local conformations of the polymer
Authors: Katsumoto Yukiteru , Tanaka Takeyuki , Ozaki Yukihiro 
Published: January 2004

AbstractStructural changes in the local conformation of poly(N‐isopropylacrylamide) (PNiPA) during the thermally and solvent‐induced coil‐globule transitions in an aqueous solution were studied by using attenuated total reflection / infrared (ATR/IR) spectroscopy combined with density functional theory (DFT) calculation. DFT calculation makes it possible to connect the spectral changes observed during the transitions with the structural changes of the local conformation of polymer chains. The results suggest that some of the intramolecular C=O···H‐N hydrogen bonds of amide groups are broken, and the changes in local conformations occur during the coil‐globule transitions of PNiPA. In this paper, an overview of our recent studies on the coil‐globule transitions of PNiPA is given for introducing a new idea that may explain the stimulus sensitivities of PNiPA in solutions; the solubility of segments concerning with the local conformation of repeating monomer units is changed by an external perturbation, and then the polymer system shows the coil‐globule transition.
Quantitative analysis throughout pregnancy of placentomal and interplacentomal expression of pregnancy‐associated glycoproteins‐1 and ‐9 in the cow
Authors: Patel Osman V. , Yamada Osamu , Kizaki Keiichiro , Takahashi Toru , Imai Kei , Hashizume Kazuyoshi 
Published: January 2004

AbstractThe multigenic pregnancy‐associated glycoproteins (PAG) exhibit spatially and temporally distinct pattern across gestation in the bovine. The majority of the bovine bPAG are localized to the binucleate cells (BNC) while some are expressed throughout the trophectoderm. Bovine (b)PAG‐1 and ‐9 are both localized to the BNC but are differentially transcribed. In addition, the anatomical location of BNC does influence protein expression in the ungulates. Therefore, the objective of the present study was to compare and contrast bPAG‐1 and ‐9 transcriptions in the placentomal (cotyledonary, caruncular) and interplacentomal (intercotyledonary, intercaruncular) tissues throughout pregnancy in the bovine using real‐time reverse transcription PCR (RT‐PCR) and by in‐situ hybridization. The levels of bPAG‐9 transcription in the fetal membrane at peri‐implantation were significantly (P < 0.01) higher than bPAG‐1. The expression of bPAG‐9 in the placentomal and interplacentomal tissues were significantly (P < 0.01) higher than bPAG‐1 during the first trimester of gestation. The transcription of bPAG‐1 in the placentomal and interplacentomal tissues were significantly (P < 0.01) higher than bPAG‐9 from mid‐gestation to peripartum. The expression of bPAG‐1 and ‐9 throughout gestation were significantly (P < 0.01) affected by the anatomical location of BNC. In situ analysis paralleled the expression patterns of bPAG‐1 and ‐9 across gestation. These findings indicate that bPAG‐9 expression in the placentomal and interplacentomal tissues predominates in the first trimester of gestation while bPAG‐1 transcription was primarily higher in the last two trimesters of gestation. The cellular location had significant effect on bPAG‐1 and ‐9 transcription. Mol. Reprod. Dev. 67: 257–263, 2004. © 2004 Wiley‐Liss, Inc.
Ovarian cysteine proteinases in the teleost Fundulus heteroclitus: Molecular cloning and gene expression during vitellogenesis and oocyte maturation
Authors: Fabra Mercedes , Cerdà Joan 
Published: January 2004

AbstractThe cysteine proteinases cathepsins B and L are members of the multigene family of lysosomal proteases that have been implicated in the processing of yolk proteins (YPs) in teleost oocytes. However, the full identification of the type of cathepsins expressed in fish ovarian follicles and embryos, as well as their regulatory mechanisms and specific function(s), are not yet elucidated. In this study, cDNAs encoding cathepsins B, L, F, K, S, Z, C, and H have been isolated from the teleost Fundulus heteroclitus, and the analysis of their deduced amino acid sequences revealed highly similar structural features to vertebrate orthologs, and confirmed in this species the existence of cathepsin L‐like, cathepsin B‐like, and cathepsin F‐like subfamilies of cysteine proteinases. While all identified cathepsins were expressed in ovarian follicles, the corresponding mRNAs showed different temporal expression patterns. Thus, similar mRNA levels of cathepsins L, F, S, B, C, and Z were found throughout the oocyte growth or vitellogenesis period, whereas those for cathepsin H and K appeared to decrease as vitellogenesis advanced. During oocyte maturation, a transient accumulation of cathepsins L, S, H, and F mRNAs, approximately a 3‐, 1.5‐, 1.6‐, and 6‐fold increase, respectively, was detected in ovarian follicles within the 20–25 hr after hormone stimulation, coincident with the maximum proteolysis of the oocyte major YPs. The specific temporal pattern of expression of these genes may indicate a potential role of cathepsin L‐like and cathepsin F proteases in the YP processing events occurring during fish oocyte maturation and/or early embryogenesis. Mol. Reprod. Dev. 67: 282–294, 2004. © 2004 Wiley‐Liss, Inc.
Dominant expression of porcine Calbindin‐D9k in the uterus during a luteal phase
Authors: Yun So‐Mi , Choi Kyung‐Chul , Kim Ill‐Hwa , An Beum‐Soo , Lee Geun‐Shik , Hong Eui‐Ju , Oh Goo‐Taeg , Jeung Eui‐Bae 
Published: January 2004

AbstractCalbindin‐D9k (CaBP‐9k) is a member of intracellular calcium binding proteins, which have a high affinity to calcium. CaBP‐9k is mainly expressed in the mammalian intestine, uterus and placenta, and is regulated in tissue‐ and species‐specific manners. Previous studies have shown that CaBP‐9k expression is mainly controlled by steroid hormones and their receptors. Thus, we further investigated the expression and regulation of CaBP‐9k during an estrus cycle in the pig uterus by Northern blot and immunoblot analysis in this study. In addition, serum levels of estrogen (E2) and progesterone (P4) were measured using ELISA. The CaBP‐9k mRNA is highly expressed in the porcine uterus during a luteal phase compared to a follicular phase, and its mRNA level in a luteal phase is increased up to 10‐fold compared to a follicular phase. In parallel to the level of CaBP‐9k mRNA, the CaBP‐9k protein is also dominantly expressed in the porcine uterus, and strongly expressed in the epithelium and glands of the porcine uterus during a luteal phase. Although, the localization of the CaBP‐9k protein is scarcely detected at follicular phase, it is dominantly expressed in the porcine uterus during a luteal phase. In addition, the serum P4 level was significantly increased during a luteal phase compared to a follicular phase, whereas no difference was observed in E2 levels between follicular and luteal phases, indicating that the ratio of P4/E2 is remarkably increased in porcine uterus during a luteal phase compared to a follicular phase. In conclusion, these results suggest that P4 may play an important role in the up‐regulation of CaBP‐9k gene in the porcine uterus in a luteal phase, which is unlike the condition in the rat uterus. In addition, the porcine CaBP‐9k may be dominantly expressed in the epithelium and glandular structure of pig uterus during a luteal phase. It may also be differentially regulated during this cycle presumably by steroid hormones, especially up‐regulated P4 levels in this tissue. Mol. Reprod. Dev. 67: 251–256, 2004. © 2004 Wiley‐Liss, Inc.
Centrosomal function assessment in human sperm using heterologous ICSI with rabbit eggs: A new male factor infertility assay
Authors: Terada Yukihiro , Nakamura Sou‐ichi , Simerly Calvin , Hewitson Laura , Murakami Takashi , Yaegashi Nobuo , Okamura Kunihiro , Schatten Gerald 
Published: January 2004

AbstractSperm centrosomal function was assessed by immunocytochemical analysis after the injection of human sperm into mature rabbit eggs. Three hours after intracytoplasmic sperm injection (ICSI), an astral microtubule array from the base of the human sperm was observed in the rabbit eggs. This sperm aster expanded in the egg cytoplasm, concommitant with pronuclear formation, and a dense microtubule array was organized at the time of pronuclear centration. Using fertile donor sperm, the sperm aster formation rate at 3 hr after ICSI was 35.0 ± 1.5%. Using sperm from infertile patients, the average aster formation rate was lower (25.4 ± 14.8%, P < 0.05). Among infertile cases, there was no correlation between sperm aster formation rates and conventional parameters of semen analysis. However, the sperm aster formation rate correlated with the embryonic cleavage rate following human in vitro fertilization (IVF). These data suggest that this assay reflects sperm function during embryonic development after sperm entry and that reproductive success during the first cell cycle requires a functional sperm centrosome. Furthermore, sperm centrosomal function cannot be predicted from conventional parameters of semen analysis. We propose that insufficient centrosomal function could be the cause of certain cases of idiopathic infertility. These assays may lead to the discovery of new types of infertility, which have previously been treated as “unexplained infertility,” and may also lead to the treatment of infertility incurable even by ICSI. Consequently, an accurate and relevant assay to help assure couples of the success of fertilization is warranted, perhaps prior to ICSI therapy. Mol. Reprod. Dev. 67: 360–365, 2004. © 2004 Wiley‐Liss, Inc.
The generalized minimum spanning tree problem: Polyhedral analysis and branch‐and‐cut algorithm
Authors: Feremans Corinne , Labbé Martine , Laporte Gilbert 
Published: January 2004

AbstractThis article presents a branch‐and‐cut algorithm for the Generalized Minimum Spanning Tree Problem (GMSTP). Given an undirected graph whose vertex set is partitioned into clusters, the GMSTP consists of determining a minimum‐cost tree including exactly one vertex per cluster. Applications of the GMSTP are encountered in telecommunications. An integer linear programming formulation is presented and new classes of valid inequalities are developed, several of which are proved to be facet‐defining. A branch‐and‐cut algorithm and a tabu search heuristic are developed. Extensive computational experiments show that instances involving up to 160 or 200 vertices can be solved to optimality, depending on whether edge costs are Euclidean or random. © 2004 Wiley Periodicals, Inc.
On some properties of suboptimal colorings of graphs
Authors: Blöchliger Ivo , de Werra D. 
Published: January 2004

AbstractStarting from the trivial observation that, in any optimal coloring of a graph, there always exists a node v such that its neighborhood N(v) contains all colors, we examine related properties in suboptimal colorings (i.e., those using more than χ(G) colors, where χ(G) is the chromatic number). In particular, we show that, in any (χ(G) + p)‐coloring of G, there is a node v such that its generalized neighborhood Nq(v) with q = max{2p − 1, 2} contains χ(G) colors for p ≥ 1. Additional properties of (χ(G) + p)‐colorings are also given. © 2004 Wiley Periodicals, Inc.
A randomized algorithm for gossiping in radio networks
Authors: Chrobak Marek , Ga̧sieniec Leszek , Rytter Wojciech 
Published: January 2004

AbstractWe present anO(nlog4n)‐time randomized algorithm for gossiping in radio networks with unknown topology. This is the first algorithm for gossiping in this model whose running time is only a polylogarithmic factor away from the optimum. The fastest previously known (deterministic) algorithm for this problem works in timeO(n3/2log2n). © 2004 Wiley Periodicals, Inc.