bluuebunny/crossref_metadata_2025 huggingface dataset:
Central and peripheral motor conduction to cremasteric muscle
Authors: Ertekin C. , Bademkiran F. , Yildiz N. , Ozdedeli K. , Altay B. , Aydogdu I. , Uludag B.
Published: January 2005

The few electrophysiologic studies of the cremasteric muscle (CM) have mainly been restricted to the cremaster reflex with no reference to central and peripheral nerve conduction to the muscle, probably for technical reasons.Twenty‐six normal adult male volunteers were studied by transcranial magnetic cortical stimulation (TMS) and stimulation of thoracolumbar roots. The genitofemoral nerve (GFN) was stimulated electrically at the anterior superior iliac spine and a needle electrode was inserted into the CM for conduction studies. The motor latency to the CM from the cortical TMS ranged from 20 to 33 ms among the subjects (25.8 ± 2.9 ms, mean ± SD). Magnetic stimulation of the lumbar roots produced a motor response of the CM within 9.6 ± 1.9 ms (range, 6–15). The central motor conduction time to the CM was 16.5 ± 2.8 ms (range, 10–21). Stimulation of the GFN produced a compound muscle action potential with a mean value of 6.4 ± 1.8 (range, 4–10) ms in 23 of the 26 cases. Thus, central motor nerve fibers to the CM motor neurons exist, and there may be a representation area for the CM in the cerebral cortex. The GFN motor conduction time to the CM may have clinical utility, such as in the evaluation of the groin pain due to surgical procedures in the lower abdomen. Muscle Nerve, 2005
Diffusion of water and artificial seawater through coir fiber reinforced natural rubber composites
Authors: Geethamma V.G. , Thomas Sabu
Published: January 2005

The diffusion of water and artificial seawater through cross‐linked coir fiber reinforced natural rubber composites was analyzed. The effect of fiber loading, chemical treatment, and bonding agent on liquid sorption was investigated. Based on the experiments, it is suggested that the probable mechanism of transport in gum compound is Fickian and that in composites is anomalous. The liquid uptake of all the composites is higher in water than that in artificial seawater. The composites showed increased swelling with fiber loading in water and artificial seawater. The influence of silica in the bonding system on swelling of the composites was also analyzed. In the case of gum compound, the desorption process is also Fickian, similar to the absorption of water and seawater. But the desorption of composites exhibited deviation from Fickian behavior. The effect of chemical treatment of coir fibers on the swelling was analyzed and found that the uptake of water and artificial seawater is reduced further in composites containing treated fibers. POLYM. COMPOS., 26:136–143, 2005. © 2005 Society of Plastics Engineers
Effect of processing conditions on flash generation
Authors: Higuchi Hiroyuki , Goto Hirofumi , Koyama Kiyohito
Published: January 2005

Reduction of flash during injection molding is of great concern for manufacturers of electrical parts. In a previous report, we proposed a theoretical model for flash generation. The present study investigates the effect of processing conditions on flash generation and then attempts to analyze the flash data in terms of the flash model. Specifically, we carry out flow analyses to predict the temperature and pressure of materials when the flash generates. With the thus‐computed parameters, and material properties such as melt viscosity and crystallization temperature, a flash parameter defined in the model is calculated. In the end, it is shown that the flash parameter is correlated with the length of flash generated under various processing conditions. POLYM. ENG. SCI. 45:238–247, 2005. © 2005 Society of Plastics Engineers
Reinforcement effect of carbon nanofillers in an epoxy resin system: Rheology, molecular dynamics, and mechanical studies
Authors: Kotsilkova R. , Fragiadakis D. , Pissis P.
Published: January 2005

The reinforcing effect of carbon nanoparticles in an epoxy resin has been estimated with different approaches based on rheology, molecular dynamics (evaluated by differential scanning calorimetry, dielectric relaxation spectroscopy, and thermally stimulated depolarization current), and dynamic mechanical analysis. Carbon particles aggregate as the volume increases and form a fractal structure in the matrix polymer. The dispersion microstructure has been characterized by its viscoelastic properties and relaxation time spectrum. The scaling of the storage modulus and yield stress with the volume fraction of carbon shows two distinct exponents and has thus been used to determine the critical carbon volume fraction of the network formation (Φ*) for the carbon/epoxy dispersions. At nanofiller concentrations greater than Φ*, the overall mobility of the polymer chains is restricted in both dispersions and solid nanocomposites. Therefore, (1) the relaxation spectrum of the dispersions is strongly shifted toward longer times, (2) the glass‐transition temperature is increased and (3) the relaxation strength of both the secondary (β) and primary (α) relaxations increases in the nanocomposites, with respect to the pure polymer matrix. The dispersion microstructure, consisting of fractal flocs and formed above Φ*, is proposed to play the main role in the reinforcement of nanocomposites. Moreover, the network structure and the interface polymer layer (bond layer), surrounding nanoparticles, increases the relaxation strength and slows the cooperative α relaxation, and this results in an improvement of the mechanical properties. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 522–533, 2005
Bi‐directional interactions of prostate cancer cells and bone marrow endothelial cells in three‐dimensional culture
Authors: Barrett Jeffrey M. , Mangold Kathy A. , Jilling Tamas , Kaul Karen L.
Published: January 2005

BACKGROUND

Prostate cancer preferentially metastasizes to bone, yet little is known about the cellular and molecular factors that support this growth. Endothelial cells are likely the initial contact for circulating prostate cells entering the bone microenvironment.

METHODS

Using co‐culture and conditioned media experiments, we studied cellular and molecular interactions of prostate cancer cells of varying aggressiveness (PC‐3 and LNCaP) with bone marrow endothelial (HBME‐1) cells in collagen gels.

RESULTS

In co‐culture, HBME‐1 cells stimulated proliferation (∼90% increase) and migration of the more aggressive PC‐3 cell line, while having little effect on LNCaP cell proliferation or migration. Concomitantly, HBME‐1 cell growth was inhibited by both PC‐3 and LNCaP cells and their conditioned media. Additionally, HBME‐1 cells underwent significant morphological changes in co‐culture, forming large, branching, cord‐like structures, which mimic angiogenesis. Prostate cancer cell conditioned media induced a similar effect on HBME‐1 cells. In comparison, conditioned media from PC‐3 cells also inhibited growth of non‐bone marrow‐derived endothelial cells, but did not affect their morphology.

CONCLUSIONS

Significant bi‐directional interactions, including secreted factors and direct cellular interactions, exist between bone marrow endothelial cells and highly metastatic prostate cancer cells, and may underlie the propensity for prostate cancer to metastasize to the bone. © 2005 Wiley‐Liss, Inc.
Increase in amphiregulin and epiregulin in prostate cancer xenograft after androgen deprivation—impact of specific HER1 inhibition
Authors: Tørring Niels , Hansen Frederik Dagnæs , Sørensen Boe Sandahl , Ørntoft Torben F. , Nexø Ebba
Published: January 2005

BACKGROUND

We investigated the expression of the epidermal growth factor (EGF) network before and after castration in the prostate cancer xenograft CWR22 implanted in nude mice, and examined the effects of gefitinib (Iresssa, ZD1839), a new drug directed towards the EGF tyrosine kinase receptor (HER1) of the EGF network.

METHODS

CWR22 prostate cancer xenografts were propagated in immunodeficient male mice. The expression of the growth factors and receptors in the EGF network was examined by real‐time PCR analysis and ELISA at 0, 7, 14, and 30 days after castration, and the tumor growth was examined after treatment with gefitinib or placebo.

RESULTS

A fraction of growth factors showed a steady increase in the mRNA expression reaching between fourfold and eightfold 30 days after castration, including amphiregulin (P < 0.005) and epiregulin (P < 0.001). ELISA for amphiregulin showed a fivefold increase 30 days after castration. Tumor bearing mice were castrated and treated with or without the HER1 tyrosine kinase inhibitor gefitinib. Tumor involution was significantly increased by castration plus gefitinib as compared to castration alone.

CONCLUSIONS

Castration leads to adaptive increase in the concentrations of a subset of growth factors from the EGF network in the androgen sensitive CWR22 prostate cancer xenograft. Specific inhibition of the HER1 tyrosine kinase receptor significantly increases the tumor involution, and suggests that HER1 targeted drugs could be of therapeutic relevance in the treatment of advanced prostate cancer. © 2005 Wiley‐Liss, Inc.
Decreasing age at prostate cancer diagnosis over successive generations in prostate cancer families
Authors: Bock Cathryn H. , Peyser Patricia A. , Montie James E. , Cooney Kathleen A.
Published: January 2005

BACKGROUND

The decline in age at prostate cancer diagnosis over the past decade is partially attributable to prostate specific antigen (PSA) screening. We examined age at diagnosis over successive generations within prostate cancer families.

METHODS

Families with at least two affected men were selected from the University of Michigan Prostate Cancer Genetics Project. The 1,345 individuals from 489 families were grouped into three generations.

RESULTS

Risk of prostate cancer diagnosis at a given age was estimated to increase 1.31 (95% CI: 1.13–1.51) times from one generation to the next. Among men diagnosed prior to the PSA era, inferences were similar (hazard ratio = 1.28, 95% CI: 0.97–1.68). No maternal versus paternal disease transmission effect was observed.

CONCLUSIONS

Age at prostate cancer diagnosis was observed to decrease over successive generations in families from an ongoing familial prostate cancer study. This finding, if confirmed, may have important implications for familial prostate cancer risk assessment. © 2005 Wiley‐Liss, Inc.
High dose fractionated ionizing radiation inhibits prostate cancer cell adhesion and β1 integrin expression
Authors: Simon Edmund L. , Goel Hira L. , Teider Natalia , Wang Tao , Languino Lucia R. , FitzGerald T.J.
Published: January 2005

BACKGROUND

The effect of ionizing radiation on extracellular matrix (ECM)‐mediated cellular functions is an important area of research for translational science. Mechanisms of tumor cell ability to proliferate, migrate, and survive appear dependent on integrin‐mediated adhesion to the ECM; however, the exact role therapeutic radiation plays in altering signaling pathways and promoting cell death within remains less well established.

METHODS

To examine these effects on prostate carcinoma cell lines, cells were irradiated at sub‐lethal doses. We have studied two human prostate cancer cell lines (PC3 and DU‐145) irradiated with different fractionated radiation schedules. Three groups were compared to non‐irradiated controls. Group A was given a single dose of 5 Gy. Group B was given 5 Gy the first week and then 10 Gy the second week for a total of 15 Gy. Group C was given 5 Gy the first week, and then 10 Gy the second and third week for a total of 25 Gy. Cells were analyzed at their prescribed total dose. At 48 hr post irradiation, cells were detached from culture dishes and were subsequently used for adhesion assays and immunoblotting analysis.

RESULTS

Our findings revealed that two prostate carcinoma cell lines, PC3 and DU‐145, had a reduced cellular adhesion to fibronectin (FN) compared to the non‐irradiated control groups. Both prostate cancer cell lines showed decreased adhesion to FN and reduced β1 integrin protein levels at a total dose of 25 Gy, but not at the doses of 15 and 5 Gy. In a parallel analysis, at the maximum total dose of 25 Gy, both PC3 and DU‐145 demonstrated a significant decrease in cell proliferation.

CONCLUSIONS

High dose radiation treatment of prostate cancer cell lines inhibits integrin expression. Our study suggests that promoting a synergistic decrease in adhesion could bring additional therapeutic benefit to patients treated with radiation therapy. © 2005 Wiley‐Liss, Inc.
Expression of tumor‐associated trypsinogens (TAT‐1 and TAT‐2) in prostate cancer
Authors: Bjartell Anders , Paju Annukka , Zhang Wan‐Ming , Gadaleanu Virgil , Hansson Jens , Landberg Göran , Stenman Ulf‐Håkan
Published: January 2005

BACKGROUND

Trypsinogens are pancreatic serine proteinases and expressed in several cancers as tumor‐associated trypsinogens (TAT). Trypsin mediates activation of pro‐uPA and pro‐MMPs, thus promoting angiogenesis and tumor invasion. Recently, we described expression of TAT in the human male genital tract and now we studied TAT in relation to PSA in PCa.

METHODS

TAT expression was studied by immunohistochemistry, in situ hybridization, RT‐PCR, DNA‐sequencing and IFMA. LNCaP cells were used to study secretion of TAT and PSA after androgen stimulation.

RESULTS

Immunoreactive TAT was localized in all prostatic tumors (n = 109), lymph node (n = 16), and bone metastases (n = 17). Immunostaining intensity increased with higher Gleason's grade, whereas PSA immunostaining decreased significantly. PSA and TAT were not identically distributed in benign and malignant cells. Androgen stimulation of LNCaP cells decreased secretion of TAT and increased that of PSA. TAT mRNA was demonstrated in tissue sections and identified as TAT‐1 and ‐2 by RT‐PCR and DNA‐sequencing.

CONCLUSIONS

Expression of TAT is better preserved than PSA in high‐grade PCa. Expression of TAT and PSA is regulated by different mechanisms as demonstrated in tissue sections and in vitro. Locally produced TAT may act in a paracrine mode to promote angiogenesis and tumor invasion in PCa by both activating and degrading of other proteinases. Further studies on the role of TAT in invasive PCa and on the mechanisms involved in the regulation of TAT expression are warranted. © 2005 Wiley‐Liss, Inc.
Exciton delocalization of the J‐aggregate of oxacyanine dye and thiacyanine dye in LB films
Authors: Yonezawa Yoshiro , Yamaguchi Atsushi , Kometani Noritsugu
Published: January 2005

Delocalization and energy transfer of the molecular exciton of the J‐aggregate of oxacyanine dye, N,N′‐dioctadecyl‐oxacyanine perchlorate (S9) in LB films have been examined. Fluorescence lifetime of the S9 J‐aggregate (S9(J)) appears to be ca. 1/20 of the isolated S9 molecules (S9(M)), which suggests that the coherent size of the J‐aggregate, Ncohe, is about 22 at room temperature. Quenching of resonance fluorescence of S9(J) by thiacyanine dye, N,N′‐dioctadecyl‐thiacyanine perchlorate (S11) obeys the Stern–Volmer relation with a Stern–Volmer constant of 1.2 × 103 nm2 molecules–1 at room temperature, which is responsible to the incoherent size Ninco of about 2000. The rate constant of energy transfer kET amounts to 1.5 × 1013 nm2 molecules–1 s–1. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Adsorption and dissociation of water on relaxed alumina clusters: a first principles study
Authors: Fernandez E. M. , Eglitis R. , Borstel G. , Balbás L. C.
Published: January 2005

Using previous results for the equilibrium geometries of stoichiometric (Al2O3)n clusters as models for non ideal alumina surfaces, we obtain, from ab‐initio total energy LCAO calculations, the corresponding relaxed structures of the complexes H2O–(Al2O3)n with n ≤ 7. Depending on the initial position of the water molecule relative to the cluster site, the complex evolves to different equilibrium structures, with and without dissociation of H2O, whose energetic, bond lengths, and charge transfer trends are studied as the morphology and size of the initial cluster change. Dissociation of H2O with the radical OH– bound on top of an Al atom and the proton H+ bound to the second nearest neighbour O, is the dominant process for the reaction (Al2O3)n + H2O with n = 4, in agreement with the one observed for the adsorption of H2O on the extended real surface. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Forms of adsorption and transition states of oxidation of carbon monoxide by molecular oxygen and dissociation of nitrogen monooxide, catalyzed by monovalent copper
Authors: Ermakov A. I. , Mashutin V. Y. , Vishnjakov A. V.
Published: January 2005

With the help of the results of semiempirical (parametric method 3) and ab initio (second‐order Møller–Plesset [MP2] unrestricted Hartree–Fock [UHF] 6‐31G**, unrestricted density functional theory [UDFT] 6‐31G** Becke's three‐parameter exchange functional and the gradient‐corrected functional of Lee, Yang, and Paar [B3LYP] and UDFT LANL2DZ B3LYP) quantum‐chemical calculations has been studied the complexation CO and NO with molecular hydroxide of copper(I). The influence of charge defects has been simulated by the calculations of anionic, neutral, and cationic systems. It is shown that CO and NO are mainly coordinated by nonoxygen atom on an atom of copper(I) hydroxide as one‐ and two‐center forms. These forms are suitable for appearance of prereactionary complexes of catalytic oxidation CO by molecular oxygen and decomposition NO into atoms of nitrogen and oxygen. The corresponding prereactionary complexes for systems with participation of copper(II) hydroxide and copper(III) hydroxide are not revealed. The calculations predict inhibiting impact of copper(II) and copper(III) of the observed reactions. Computed stability of complexes CO and NO with copper(I) hydroxide and activation energy of catalytic conversion of monooxides essentially depend on an excessive charge of the system. Introduction of electron‐donating additives into copper(I) hydroxide promotes rise of catalytic activity of copper(I) compound. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Polaron‐induced conformation change in single polypyrrole chain: An intrinsic actuation mechanism
Authors: Lin Xi , Li Ju , Smela Elisabeth , Yip Sidney
Published: January 2005

Ab initio calculations show that a neutral polypyrrole chain in the ground state assumes a helical shape resulting from a novel bending mechanism, while upon oxidation the chain becomes planar within the polarons, an effect due to enhanced inter‐ring π bonding. This polaron‐induced conformation change leads to an intrinsic potential for inducing macroscopic strains in the single chain, with implications for further theoretical studies and experiments. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Spectral properties of minimal‐basis‐set orbitals: Implications for molecular electronic continuum states
Authors: Langhoff P. W. , Winstead C. L.
Published: January 2005

Early studies of the electronically excited states of molecules by John A. Pople and coworkers employing ab initio single‐excitation configuration interaction (SECI) calculations helped to simulate related applications of these methods to the partial‐channel photoionization cross sections of polyatomic molecules. The Gaussian representations of molecular orbitals adopted by Pople and coworkers can describe SECI continuum states when sufficiently large basis sets are employed. Minimal‐basis virtual Fock orbitals stabilized in the continuous portions of such SECI spectra are generally associated with strong photoionization resonances. The spectral attributes of these resonance orbitals are illustrated here by revisiting previously reported experimental and theoretical studies of molecular formaldehyde (H2CO) in combination with recently calculated continuum orbital amplitudes. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
The use of elementary reaction coordinates in the search for conical intersections
Authors: Haas Yehuda , Cogan Semyon , Zilberg Shmuel
Published: January 2005

A method to locate conical intersections between the ground‐state potential surface and the first electronically excited states of polyatomic molecules is described. It is an extension of the Longuet‐Higgins sign‐change theorem and uses reaction coordinates of elementary reactions as the starting point of the analysis. It is shown that the complete molecular landscape 1 can be partitioned into 2‐D domains, each bordered by a Longuet‐Higgins loop formed from reaction coordinates of elementary reactions. A domain may contain a conical intersection and if it does, it contains only one (the uniqueness theorem), whose energy is higher than the neighboring minima or transition states. The method can be helped by symmetry, but applies also to systems having no symmetry elements. It is demonstrated for some simple cases. The presence of a conical intersection is manifested by the nature of ground‐state thermal reactions, as shown for instance by the fact that the transition state in the ring opening of the cyclopropyl radical is nonsymmetric. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
DFT and experimental studies of the structure and vibrational spectra of curcumin
Authors: Kolev Tsonko M. , Velcheva Evelina A. , Stamboliyska Bistra A. , Spiteller Michael
Published: January 2005

The potential energy surface of curcumin [1,7‐bis(4‐hydroxy‐3‐methoxyphenyl)‐1,6‐heptadiene‐3,5‐dione] was explored with the DFT correlation functional B3LYP method using 6‐311G* basis. The single‐point calculations were performed at levels up to B3LYP/6‐311++G**//B3LYP/6‐311G*. All isomers were located and relative energies determined. According to the calculation the planar enol form is more stable than the nonplanar diketo form. The results of the optimized molecular structure are presented and compared with the experimental X‐ray diffraction. In addition, harmonic vibrational frequencies of the molecule were evaluated theoretically using B3LYP density functional methods. The computed vibrational frequencies were used to determine the types of molecular motions associated with each of the experimental bands observed. Our vibrational data show that in both the solid state and in all studied solutions curcumin exists in the enol form. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Density functional study of the heme moiety of cytochrome c
Authors: Kumar Anil , Mishra P. C. , Verma C. S. , Renugopalakrishnan V.
Published: January 2005

A model of cytochrome c (Cyt‐c) including the porphyrin ring, a methionine residue (Met), and the imidazole ring of histidine (His), the latter two being situated above and below the iron (Fe) atom of the porphyrin ring, was studied using Density Functional Theory (DFT). The geometries of the model Cyt‐c complex with the Fe atom in two different charge states were fully optimized, i.e., in singlet and triplet states for Fe and in doublet and quartet states for Fe3+. The B3LYP method of DFT along with the 3‐21G* basis set for C, H, N, and O atoms and the Lanl2dz basis set for the Fe atom was used. We found that with Fe3+, the doublet spin state is the ground state and the quartet state lies slightly above it. The geometry of the singlet spin state is similar to that of the doublet and quartet states. However, methionine has different conformations when Fe has zero charge (singlet, triplet states) relative to the situation when Fe has +3 charges (doublet, quartet states). The Met chain is folded instead of remaining extended in going from the singlet or triplet spin state to the doublet or quartet state and the folding is stabilized by an intramolecular CH..O hydrogen bond. The optimized geometrical parameters of the model of Cyt‐c are usually in satisfactory agreement with those observed experimentally. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Random subgraphs of finite graphs: I. The scaling window under the triangle condition
Authors: Borgs Christian , Chayes Jennifer T. , van der Hofstad Remco , Slade Gordon , Spencer Joel
Published: January 2005

We study random subgraphs of an arbitrary finite connected transitive graph 𝔾 obtained by independently deleting edges with probability 1 − p. Let V be the number of vertices in 𝔾, and let Ω be their degree. We define the critical threshold pc = pc (𝔾, λ) to be the value of p for which the expected cluster size of a fixed vertex attains the value λV1/3, where λ is fixed and positive. We show that, for any such model, there is a phase transition at pc analogous to the phase transition for the random graph, provided that a quantity called the triangle diagram is sufficiently small at the threshold pc. In particular, we show that the largest cluster inside a scaling window of size |p − pc| = Θ(Ω−1V−1/3) is of size Θ(V2/3), while, below this scaling window, it is much smaller, of order O(ϵ−2 log(Vϵ3)), with ϵ = Ω(pc − p). We also obtain an upper bound O(Ω(p − pc)V) for the expected size of the largest cluster above the window. In addition, we define and analyze the percolation probability above the window and show that it is of order Θ(Ω(p − pc)). Among the models for which the triangle diagram is small enough to allow us to draw these conclusions are the random graph, the n‐cube and certain Hamming cubes, as well as the spread‐out n‐dimensional torus for n > 6. © 2005 Wiley Periodicals, Inc. Random Struct. Alg., 2005
Counting subgraphs in quasi‐random 4‐uniform hypergraphs
Authors: Rödl Vojtĕch , Skokan Jozef
Published: January 2005

A bipartite graph G = (V1 ∪ V2, E) is (δ, d)‐regular if

whenever $V^{\prime}_{i}\subset V_{i}, |V^{\prime}_{i}| \geq \delta|V_{i}|, i = 1,2.$ Here, $d(V^{\prime}_{1}, V^{\prime}_{2}) = e(V^{\prime}_{1}, V^{\prime}_{2})/|V^{\prime}_{1}||V^{\prime}_{2}|$ stands for the density of the pair $(V^{\prime}_{1}, V^{\prime}_{2}).$ An easy counting argument shows that if G = (V1 ∪ V2 ∪ V3, E) is a 3‐partite graph whose restrictions on V1 ∪ V2, V1 ∪ V3, V2 ∪ V3 are (δ, d)‐regular, then G contains $(d^{3} \pm f(\delta))|V_{1}||V_{2}||V_{3}|$ copies of K3. This fact and its various extensions are the key ingredients in most applications of Szemerédi's Regularity Lemma. To derive a similar results for r‐uniform hypergraphs, r > 2, is a harder problem. In 1994, Frankl and Rödl developed a regularity lemma and counting argument for 3‐uniform hypergraphs. In this paper, we exploit their approach to develop a counting argument for 4‐uniform hypergraphs. © 2005 Wiley Periodicals, Inc. Random Struct. Alg., 2005
In vivo involvement of mutated initiation factor IF1 in gene expression control at the translational level
Authors: Croitoru Victor V. , Bucheli-Witschel Margarete , Isaksson Leif A.
Published: January 2005

The influence in vivo of mutated forms of translation initiation factor (IF1) on the expression of the lacZ or 3A′ reporter genes, with different initiation and/or +2 codons, has been investigated. Reporter gene expression in these infA(IF1) mutants is similar to the wild‐type strain. The results do not support the longstanding hypothesis that IF1 could perform discriminatory functions while blocking the aminoacyl‐tRNA acceptor site (A‐site) of the ribosome. One cold‐sensitive IF1 mutant shows a general overexpression, in particular at low temperatures, of both reporter genes at the protein but not mRNA level.
Hitchhiking and recombination in birds: evidence from Mhc-linked and unlinked loci in Red-winged Blackbirds (Agelaius phoeniceus)
Authors: EDWARDS SCOTT V. , DILLON MEGAN
Published: January 2005

Hitchhiking phenomena and genetic recombination have important consequences for a variety of fields for which birds are model species, yet we know virtually nothing about naturally occurring rates of recombination or the extent of linkage disequilibrium in birds. We took advantage of a previously sequenced cosmid clone from Red-winged Blackbirds (Agelaius phoeniceus) bearing a highly polymorphic Mhc class II gene, Agph-DAB1, to measure the extent of linkage disequilibrium across ~40 kb of genomic DNA and to determine whether non-coding nucleotide diversity was elevated as a result of physical proximity to a target of balancing selection. Application of coalescent theory predicts that the hitchhiking effect is enhanced by the larger effective population size of blackbirds compared with humans, despite the presumably higher rates of recombination in birds. We surveyed sequence polymorphism at three Mhc-linked loci occurring 1·5–40 kb away from Agph-DAB1 and found that nucleotide diversity was indistinguishable from that found at three presumably unlinked, non-coding introns (β-actin intron 2, β-fibrinogen intron 7 and rhodopsin intron 2). Linkage disequilibrium as measured by Lewontin's D' was found only across a few hundred base pairs within any given locus, and was not detectable among any Mhc-linked loci. Estimated rates of the per site recombination rate ρ derived from three different analytical methods suggest that the amounts of recombination in blackbirds are up to two orders of magnitude higher than in humans, a discrepancy that cannot be explained entirely by the higher effective population size of blackbirds relative to humans. In addition, the ratio of the number of estimated recombination events per mutation frequently exceeds 1, as in Drosophila, again much higher than estimates in humans. Although the confidence limits of the blackbird estimates themselves span an order of magnitude, these data suggest that in blackbirds the hitchhiking effect for this region is negligible and may imply that the per site per individual recombination rate is high, resembling those of Drosophila more than those of humans.
Individual organisms as units of analysis: Bayesian-clustering alternatives in population genetics
Authors: MANK JUDITH E. , AVISE JOHN C.
Published: January 2005

Population genetic analyses traditionally focus on the frequencies of alleles or genotypes in ‘populations’ that are delimited a priori. However, there are potential drawbacks of amalgamating genetic data into such composite attributes of assemblages of specimens: genetic information on individual specimens is lost or submerged as an inherent part of the analysis. A potential also exists for circular reasoning when a population's initial identification and subsequent genetic characterization are coupled. In principle, these problems are circumvented by some newer methods of population identification and individual assignment based on statistical clustering of specimen genotypes. Here we evaluate a recent method in this genre – Bayesian clustering – using four genotypic data sets involving different types of molecular markers in non-model organisms from nature. As expected, measures of population genetic structure (FST and ΦST) tended to be significantly greater in Bayesian a posteriori data treatments than in analyses where populations were delimited a priori. In the four biological contexts examined, which involved both geographic population structures and hybrid zones, Bayesian clustering was able to recover differentiated populations, and Bayesian assignments were able to identify likely population sources of specific individuals.
Effect of protein concentration, pH, lactose content and pasteurization on thermal gelation of acid caprine whey protein concentrates
Authors: Bordenave-Juchereau Stéphanie , Almeida Bruno , Piot Jean-Marie , Sannier Frédéric
Published: January 2005

The influence of pH (4·5–6·5), sodium chloride content (125–375 mM), calcium chloride content (10–30 mM), protein concentration (70–90 g/l) and lactose content on the gel hardness of goat whey protein concentrate (GWPC) in relation to the origin of the acid whey (raw or pasteurized milk) was studied using a factorial design. Gels were obtained after heat treatment (90 °C, 30 min). Gel hardness was measured using texture analyser. Only protein concentration and pH were found to have a statistically significant effect on the gel hardness. An increase in the protein concentration resulted in an increase in the gel hardness. GWPC containing 800 g/kg protein formed gels with a hardness maximum at the pHi, whereas GWPC containing 300 g/kg protein did not form true gels. Whey from pasteurized milk formed softer gels than whey from raw milk. A high lactose content (≈360 g/kg) also reduced the gelation performance of GWPC.
Potential applications of high pressure homogenisation in processing of liquid milk
Authors: Hayes Maurice G , Fox Patrick F , Kelly Alan L
Published: January 2005

Studies of the potential of high pressure homogenisation (HPH) for the combined pasteurisation/homogenisation of raw bovine milk were undertaken. Raw milk was preheated to 45 °C and HPH-treated at 150, 200 or 250 MPa; milk outlet temperature at these pressures were 67, 76·8 and 83·6 °C, respectively, with a holding time of ~20 s. Raw and commercially pasteurized and homogenized (CPH) milk samples were analysed as controls. Fat globules in HPH samples were approximately half the size of those in CPH samples, although differences were not significant (P>0·05). β-Lactoglobulin was denatured at pressures [ges ]150 MPa, although little denaturation of α-lactalbumin was observed. Numbers of psychrotrophic bacteria in raw milk were reduced by 2·73 log cycles by HPH at 150 MPa and were uncountable following HPH at 200 or 250 MPa. Mesophilic bacterial counts were reduced by 1·30, 1·83 and 3·06 log cycles by HPH at 150, 200 or 250 MPa, respectively. No viable Staphylococcus aureus nor coliform cells remained in any HPH milk samples. HPH did not affect the colour of milk and HPH samples did not cream during refrigerated storage. The activities of plasmin, alkaline phosphatase and lactoperoxidase in milk were all greatly reduced by HPH. Pseudomonas fluorescens, inoculated into milk (~106 cfu/ml), was reduced to undetectable levels by HPH at 200 MPa (milk inlet temperature, ~10 °C); however, Ps. fluorescens proteinase was quite resistant to HPH under such conditions. Overall, owing to the significant increase in temperature and the possibility of varying the holding time, there may be potential applications for HPH as a novel liquid milk processing technique, combining many advantages of conventional homogenization and pasteurization of milk in a single process.
Effects on milk yield of milking interval regularity and teat cup attachment failures with robotic milking systems
Authors: Bach Alex , Busto Isabel
Published: January 2005

A database consisting of 35291 milking records from 83 cows was built over a period of 10 months with the objectives of studying the effect of teat cup attachment failures and milking interval regularity on milk production with an automated milking system (AMS). The database collected records of lactation number, days in milk (DIM), milk production, interval between milkings (for both the entire udder and individual quarters in case of a teat cup attachment failure) and average and peak milk flows for each milking. The weekly coefficient of variation (CV) of milking intervals was used as a measure of milking regularity. DIM, milking intervals, and CV of milking intervals were divided into four categories coinciding with the four quartiles of their respective distributions. The data were analysed by analysis of variance with cow as a random effect and lactation number, DIM, the occurrence of a milking failure, and the intervals between milkings or the weekly CV of milking intervals as fixed effects. The incidence of attachment failures was 7·6% of total milkings. Milk production by quarters affected by a milking failure following the failure was numerically greater owing to the longer interval between milkings. When accounting for the effect of milking intervals, milk production by affected quarters following a milking failure was 26% lower than with regular milkings. However, the decrease in milk production by quarters affected by milking failures was more severe as DIM increased. Average and peak milk flows by quarters affected by a milking failure were lower than when milkings occurred normally. However, milk production recovered its former level within seven milkings following a milking failure. Uneven frequency (weekly CV of milking intervals >27%) decreased daily milk yield, and affected multiparous more negatively than primiparous cows.
Visual appearance and CMT score of foremilk of individual quarters in relation to cell count of cows milked automatically
Authors: Rasmussen Morten D , Bjerring Martin , Skjøth Flemming
Published: January 2005

The objectives of the study were: to evaluate the interaction between visual appearance and California mastitis test (CMT) score of the foremilk in relation to the cell count of the milk; to evaluate the consequences of sorting milk according to these criteria; and to explore whether visual appearance and CMT score of foremilk depended on the time interval between milkings. Measuring somatic cell count (SCC) in composite milk only and discarding milk above certain thresholds will not ensure that milk from all cows with visually abnormal foremilk is withheld from delivery. Low thresholds of SCC will reduce the frequency of cows with abnormal milk but increase the discarding of milk from cows with visually normal foremilk. CMT score of foremilk differentiated better between cows with high and low SCC in composite milk than visual inspection of foremilk. CMT scores of foremilk decreased with increasing interval between milkings within cow, whereas the visual appearance was independent of the interval. We propose that visual appearance of the foremilk should be kept as a criterion for sorting milk at time of milking. For test purposes, the use of visual appearance of foremilk for differentiation between normal and abnormal milk has to be done on multiple milkings. Additionally, CMT scoring of foremilk improves correct classification of normal and abnormal quarters and especially when including data from the previous milking.
Chinese Foreign Policy: Pragmatism and Strategic Behavior. Edited by Suisheng Zhao. [Armonk, NY and London: M.E. Sharpe, 2004. 319 pp. $26.95. ISBN 0-7656-1285-2.]
Authors: Belton Patrick
Published: January 2005

Suisheng Zhao has assembled this volume from articles recently published in the Journal of Contemporary China, which he edits. Its chapters cover recognizable terrain for political scientists: whether China, as a rising power, will seek to maximize its relative or absolute gains; the likelihood its increasing power will tend towards status-quo or belligerent lines; and the degree of Chinese ‘exceptionalism’ when compared with other countries. As the subtitle might suggest, the contributions present China in a favourable light, stressing how China's leaders have spurned ideological purism for the pragmatic weighing of national interests, with only nationalism to serve as a double-edged sword by conferring legitimacy on the government, but potentially also taking it away. The assertion that strategic calculations govern Chinese foreign policy contrasts with other interpretations, such as those of David Lampton in Same Bed, Different Dreams, who assigns a large role to domestic politics, or Peter Gries in Understanding Chinese Nationalism, who highlights the constraining role of nationalist ideology on the ability of China's leaders to de-escalate crises with other countries. Zhao's contribution lies less in defending the assertion of pragmatism against those competing perspectives and more in drawing upon it in offering fresh material.
Biology and Revolution in Twentieth-Century China. By Laurence Schneider. [Lanham, MD: Rowman and Littlefield Publishers, 2003. xi +305 pp. ISBN 0-7425-2696-8.]
Authors: Dikötter Frank
Published: January 2005

Readers who expect a comprehensive analysis of biological science in modern China, as the blurb on the jacket promises, may be disappointed: this book specifically contrasts the small community of followers of T. H. Morgan in Republican China with the state-sponsored rise of Lysenkoism after 1949. The first part follows the development of genetics and evolutionary theory in three universities in China, namely National Central University in Nanjing; the missionary school of Yanjing University in Beijing, linked to the Rockefeller Foundation's Peking Union Medical College; and Nanjing University, an American missionary school closely tied to Cornell. The author shows that training in biology and genetics developed in these three schools, thanks to substantial philanthropic involvement from the United States, as a “transfer” of knowledge took place between Chinese life scientists and major American institutions.

While the author presents valuable biographies of a small number of scientists such as Chen Zhen, Tan Jiazhen and Tang Peisong, and succeeds in recreating the political and institutional context within which these three geneticists operated, his work is insufficiently grounded in primary sources. The literature produced by biologists in Republican China is never invoked in any systematic way, the first chapter being largely based on Chen Zhen's biology textbook to create the impression of a neat “transfer” of knowledge from the United States. However, incompatible theories in biology were often invoked, contradictory ideas about evolution were bandied around, and vague phrases on “struggle for survival” were widespread in dozens of biology textbooks, many far more popular than Chen Zhen's work: neo-Lamarckism and Mendel-Morganism were never tidily organized into two “schools,” and they could even overlap, as very different writers from complex backgrounds struggled to make sense of an ever-growing global repertoire of biological theories. In Europe and the United States too, biologists disagreed over the relative importance of nurture versus nature, and China was no exception: diversity, elided by the author in favour of a fairly simplistic notion of an American success in Republican China before the failure of Lysenkoism under Soviet influence, is precisely what makes pre-1949 biology such a fascinating field.
Identification of infrasound produced by sprites during the Sprite2003 campaign
Authors: Farges T. , Blanc E. , Le Pichon A. , Neubert T. , Allin T. H.
Published: January 2005

During the summer of 2003, complementary measurements were taken in Europe during the Sprite2003 campaign to study sprites and associated processes. On July 21, 28 sprites observed by light‐sensitive optical cameras located at the Observatoire du Pic du Midi in the Pyrenees mountains were found to correlate with chirp‐like signals of several tenth to few minutes duration, measured by an infrasound station at Flers about 400 km from the thunderstorm. The sprite activity identified by the infrasound signature continued past sunrise into the daytime when optical systems cannot be used, documenting the occurrence of daytime sprites. Using an acoustic wave propagation model, the observed propagation delays, frequency dispersion, and duration of the infrasound bursts are found to be consistent with source altitudes at 60–80 km with horizontal dimensions equal to the optical width of the sprites. The chirp‐like dispersion is a result of the propagation properties in the earth‐thermosphere waveguide.
Density enhancement in plasmasphere‐ionosphere plasma during the 2003 Halloween Superstorm: Observations along the 330th magnetic meridian in North America
Authors: Chi P. J. , Russell C. T. , Foster J. C. , Moldwin M. B. , Engebretson M. J. , Mann I. R.
Published: January 2005

On October 29–31, 2003, the ground observations of field line resonance signals and the total electron content (TEC) along the 330th magnetic meridian recorded extraordinary density variations in both the magnetosphere and the ionosphere. In the magnetosphere, the density decreased at outer L shells due to strong convection, whereas it increased significantly in the afternoon sector at L ≤ 4. In the ionosphere, a strong positive storm occurred at low latitudes, and storm enhanced density was also observed at approximately 1400 LT in mid‐latitude regions. The density enhancements in both the magnetosphere and ionosphere coincided with intervals of southward IMF and high‐speed solar wind, consistent with the scenario that the eastward electric field imposed on the ionosphere led to a positive storm which might contribute to the dense plasmaspheric drainage plume. These results demonstrate that the ionosphere can be an important factor modulating the density variations in a storm‐time plasmasphere.
Equatorward expansion of the westward electrojet during magnetically disturbed periods
Authors: Ahn B.‐H. , Chen G. X. , Sun W. , Gjerloev J. W. , Kamide Y. , Sigwarth J. B. , Frank L. A.
Published: January 2005

The auroral electrojet (AE) indices have widely been used in various fields of solar terrestrial physics since their introduction to the community. Recently, it has been reported that the AE indices do not, at times, properly monitor the auroral electrojets because as magnetic activity increases, they expand equatorward beyond the standard AE network, resulting in a serious underestimation of the auroral electrojet intensity. It is particularly the case during severe geomagnetic storms. To determine quantitatively the equatorial expansion of the auroral electrojets, we examined an extensive database obtained from the Alaska, International Monitor for Auroral Geomagnetic Effects (IMAGE), and Canadian Auroral Network for the OPEN Program Unified Study chain of magnetometers. These chains of magnetometers enable us to determine the latitude where the maximum current density of the auroral electrojet flows. It is generally understood that the center of the auroral electrojet tends to migrate equatorward with an increase in magnetic activity. We note, however, that there seems to be a lower limit particularly of the westward electrojet, ∼60° in corrected geomagnetic latitude, regardless of magnetic activity levels. The relative location of the westward electrojet with respect to the global auroral image taken from the Polar satellite is also examined. Contrary to the generally accepted notion, the auroral electrojets are found to be most intense not in the region of bright auroral luminosity but slightly poleward of it in less luminous region. The current center seems to be the region where both ionospheric conductivity and electric field become significantly high.
Structure of the magnetic pileup boundary at Mars and Venus
Authors: Bertucci C. , Mazelle C. , Acuña M. H. , Russell C. T. , Slavin J. A.
Published: January 2005

The magnetic pileup boundary (MPB) is a sharp, thin, and well‐defined plasma boundary located between the bow shock and the inner ionospheric boundary at comets, Mars, and Venus. This boundary separates the magnetosheath, a region of low magnetic fields with a conspicuous wave activity, from the magnetic pileup region dominated by strong, highly organized magnetic fields as a result of the pileup and draping of the interplanetary magnetic field. In the present paper we study the magnetic structure of the magnetic pileup boundary at Mars and Venus by means of the technique of minimum variance of the magnetic field. For each one of the crossings analyzed, we obtain a very well defined minimum variance vector. At Mars the direction of this vector agrees with the normal to the MPB fit obtained from Mars Global Surveyor crossings. The results confirm that the MPB is a well‐defined plasma boundary. According to empirical criteria based on minimum variance analysis results, the Martian and Venusian MPB crossings would resemble an MHD tangential discontinuity rather than a rotational discontinuity. However, spacecraft observations suggest that the nature of the MPB could be far more complex. We compare our results with similar studies at the MPB of comets and the magnetic tail boundary of Titan, and we discuss the nature of the boundary from a general perspective.