bluuebunny/crossref_metadata_2025 huggingface dataset:
Rheological behavior of reactive miscible polymer blends: Influence of mixing and annealing before crosslinking
Authors: Serra C. , Bouquey M. , Schlatter G. , Muller R.
Published: September 2005

We followed crosslinking reactions in the blends of two miscible reactive polymers by either torque rheometry or dynamic rheological measurements. Functional polymers with controlled glass‐transition temperatures (Tg's), chain lengths, and number of reactive groups per chain were synthesized by bulk radical polymerization. The blends were prepared either in a batch mixer or directly in the parallel plate geometry of a dynamic rheometer. Because of the low Tg of the blend components, it was possible to separate the mixing step from the crosslinking reaction, which was followed by small amplitude dynamic measurements at a higher temperature. The kinetics of the crosslinking reaction were determined by the study of the variations of the storage modulus (G′) as a function of the reaction time. In this study, we focused on investigating the influence of blend composition, crosslinking reaction temperature, and amount of shear generated during the mixing step on the reaction kinetics. The influence of annealing time after the preshear step was also investigated. We found that the mixing procedure in the internal mixer produced homogeneous blends for which G′ was dependent on the reaction time. Moreover, the reaction rate increased as the temperature and the chain functionality increased. A first approach showed that reduced variables could be defined from G′ and reaction time with the initial concentration of the functional units to obtain a master curve independent of the species concentration. For blends prepared directly between the parallel plates of the dynamic rheometer, G′ and the subsequent reaction rate were strongly dependent on the amount of shear generated during the mixing step. However, at high enough shear, the blend was perfectly mixed and the increase in G′ versus reaction time was comparable to that obtained for the blend prepared in the internal mixer. Surprisingly, the higher the annealing time was, the lower the increase in G′ was. However, we could explained this by considering the fact that the reaction started during the annealing step, which therefore, led to a thin crosslinked layer, which prevented any further diffusion of the polymer chains. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1978–1995, 2005
E‐cadherin synergistically induces hepatospecific phenotype and maturation of embryonic stem cells in conjunction with hepatotrophic factors
Authors: Dasgupta Anouska , Hughey Rebecca , Lancin Perry , Larue Lionel , Moghe Prabhas V.
Published: September 2005

Since effective cell sourcing is a major challenge for the therapeutic management of liver disease and liver failure, embryonic stem (ES) cells are being widely investigated as a promising source of hepatic‐like cells with their proliferative and pluripotent capacities. Cell–cell interactions are crucial in embryonic development modulating adhesive and signaling functions; specifically, the cell–cell adhesion ligand, cadherin is instrumental in gastrulation and hepatic morphogenesis. Inspired by the role of cadherins in development, we investigated the role of expression of E‐cadherin in cultured murine ES cells on the induction of hepatospecific phenotype and maturation. The cadherin‐expressing embryonic stem (CE‐ES) cells intrinsically formed pronounced cell aggregates and cuboidal morphology whereas cadherin‐deficient cadherin‐expressing embryonic stem (CD‐ES) cells remained more spread out and corded in morphology. Through controlled stimulation with single or combined forms of hepatotrophic growth factors; hepatocyte growth factor (HGF), dexamethasone (DEX) and oncostatin M (OSM), we investigated the progressive maturation of CE‐ES cells, in relation to the control, CD‐ES cells. Upon growth factor treatment, the CE‐ES cells adopted a more compacted morphology, which exhibited a significant hepatocyte‐like cuboidal appearance in the presence of DEX‐OSM‐HGF. In contrast, the CD‐ES cells exhibited a mixed morphology and appeared to be more elongated in the presence of DEX‐OSM‐HGF. Reverse‐transcriptase polymerase chain reaction was used to delineate the most differentiating condition in terms of early (alpha‐fetoprotein (AFP)), mid (albumin), and late‐hepatic (glucose‐6‐phosphatase) markers in relation to growth factor presentation for both CE‐ES and CD‐ES cells. We report that following the most differentiating condition of DEX‐OSM‐HGF stimulation, CE‐ES cells expressed increased levels of albumin and glucose‐6‐phosphatase, whereas the CD‐ES cells showed low levels of AFP and marginal levels of albumin and glucose‐6‐phosphatase. These trends suggest that the membrane expression of E‐cadherin in ES cells can elicit a marked response to growth factor stimulation and lead to the induction of later stages of hepatocytic maturation. Thus, cadherin‐engineered ES cells could be used to harness the cross‐talk between the hepatotrophic and cadherin‐based signaling pathways for controlled acceleration of ES hepatodifferentiation. © 2005 Wiley Periodicals, Inc.
Topological Effects of a Rigid Chiral Spacer on the Electronic Interactions in Donor–Acceptor Ensembles
Authors: Guldi Dirk M. , Giacalone Francesco , de la Torre Gema , Segura José L. , Martín Nazario
Published: September 2005

Two triads (donor–spacer–acceptor), exTTF–BN–C60 (6) and ZnP–BN–C60 (7), in which electron donors (i.e., exTTF or ZnP) are covalently linked to C60 through a chiral binaphthyl bridge (BN), have been prepared in a multistep synthetic procedure starting from a highly soluble enantiomerically pure binaphthyl building block (1). Unlike other oligomeric bridges, with binaphthyl bridges, the conjugation between the donor and the acceptor units is broken and geometric conformational changes are facilitated. Consequently, distances and electronic interactions between the donor and C60 are drastically changed. Both donor–spacer–acceptor (D–s–A) systems (i.e., 6 and 7) exhibit redox processes that correspond to all three constituent electroactive units, namely, donor, BN, and C60. Appreciable differences were, however, observed when comparing triad 6, in which no significant exTTF–C60 interactions were noted, with D–s–A 7, whose geometry favors donor–acceptor and π–π interactions that result in ZnP–C60 electronic communication. This through‐space interaction is, for example, reflected in the redox potentials. Excited‐state studies, carried out by fluorescence and transient absorption spectroscopy, also support through‐space rather than through‐bond interactions. Although both triads form the corresponding radical‐ion pair, that is, exTTF.+–BN–C60.− and ZnP.+–BN–C60.−, dramatic differences were found in their lifetimes: 165 μs and 730 ns, respectively.
Studies of “Pinwheel‐Like” Bis[1,8,15,22‐tetrakis(3‐pentyloxy)phthalocyaninato] Rare Earth(III) Double‐Decker Complexes
Authors: Wang Rongming , Li Renjie , Bian Yongzhong , Choi Chi‐Fung , Ng Dennis K. P. , Dou Jianmin , Wang Daqi , Zhu Peihua , Ma Changqin , Hartnell Regan D. , Arnold Dennis P. , Jiang Jianzhuang
Published: September 2005

Homoleptic bis(phthalocyaninato) rare‐earth double‐deckers complexes [MIII{Pc(α‐OC5H11)4}2] (M=Eu, Y, Lu; Pc(α‐OC5H11)4=1,8,15,22‐tetrakis(3‐pentyloxy)phthalocyaninate) have been prepared by treating the metal‐free phthalocyanine H2Pc(α‐OC5H11)4 with the corresponding M(acac)3⋅nH2O (acac=acetylacetonate) in refluxing n‐octanol. Due to the C4h symmetry of the Pc(α‐OC5H11)4 ligand and the double‐decker structure, all the reactions give a mixture of two stereoisomers with C4h and D4 symmetry. The former isomer, which is a major product, can be partially separated by recrystallization due to its higher crystallinity. The molecular structure of the major isomer of the Y analogue has been determined by single‐crystal X‐ray diffraction analysis. The metal center is eight‐coordinate bound to the isoindole nitrogen atoms of the two phthalocyaninato ligands, forming a distorted square antiprism. Such an arrangement leads to an interesting “pinwheel” structure when viewed along the C4 axis, which assumes a very unusual S8 symmetry. The major isomers of all these double‐deckers have also been characterized with a wide range of spectroscopic methods. A systematic investigation of their electronic absorption and electrochemical data reveals that the π–π interaction between the two Pc(α‐OC5H11)4 rings is weaker than that for the corresponding unsubstituted or β‐substituted bis(phthalocyaninato) analogues.
Norrisolide: Total Synthesis and Related Studies
Authors: Brady Thomas P. , Kim Sun Hee , Wen Ke , Kim Charles , Theodorakis Emmanuel A.
Published: September 2005

A stereoselective synthesis of (+)‐norrisolide is presented. This natural product belongs to a family of marine spongiane diterpenes the structure of which is characterized by a fused γ‐lactone–γ‐lactol ring system attached to a bicyclic hydrophobic core. Our studies led to the development of a expedient synthesis of such γ‐lactone–γ‐lactol motifs based on ring expansion of a fused cyclopropyl ester. Highlights of the synthetic strategy toward norrisolide include the coupling of the two bicyclic systems by constructing a sterically demanding C9C10 bond and the installation of the C19 oxygen at the last step of the synthesis via a Baeyer–Villiger oxidation.
Synthesis and Characterization of Dinuclear Ruthenium Complexes Covalently Linked to RuII Tris‐bipyridine: An Approach to Mimics of the Donor Side of Photosystem II
Authors: Xu Yunhua , Eilers Gerriet , Borgström Magnus , Pan Jingxi , Abrahamsson Maria , Magnuson Ann , Lomoth Reiner , Bergquist Jonas , Polívka Tomáš , Sun Licheng , Sundström Villy , Styring Stenbjörn , Hammarström Leif , Åkermark Björn
Published: September 2005

To mimic the electron‐donor side of photosystem II (PSII), three trinuclear ruthenium complexes (2, 2 a, 2 b) were synthesized. In these complexes, a mixed‐valent dinuclear ${{\rm Ru}{{{\rm II}{\rm \char44}{\rm III}\hfill \atop 2\hfill}}}$ moiety with one phenoxy and two acetato bridges is covalently linked to a RuII tris‐bipyridine photosensitizer. The properties and photoinduced electron/energy transfer of these complexes were studied. The results show that the ${{\rm Ru}{{{\rm II}{\rm \char44}{\rm III}\hfill \atop 2\hfill}}}$ moieties in the complexes readily undergo reversible one‐electron reduction and one‐electron oxidation to give the ${{\rm Ru}{{{\rm II}{\rm \char44}{\rm II}\hfill \atop 2\hfill}}}$ and ${{\rm Ru}{{{\rm III}{\rm \char44}{\rm III}\hfill \atop 2\hfill}}}$ states, respectively. This could allow for photooxidation of the sensitizer part with an external acceptor and subsequent electron transfer from the dinuclear ruthenium moiety to regenerate the sensitizer. However, all trinuclear ruthenium complexes have a very short excited‐state lifetime, in the range of a few nanoseconds to less than 100 ps. Studies by femtosecond time‐resolved techniques suggest that a mixture of intramolecular energy and electron transfer between the dinuclear ruthenium moiety and the excited [Ru(bpy)3]2+ photosensitizer is responsible for the short lifetimes. This problem is overcome by anchoring the complexes with ester‐ or carboxyl‐substituted bipyridine ligands (2 a, 2 b) to nanocrystalline TiO2, and the desired electron transfer from the excited state of the [Ru(bpy)3]2+ moiety to the conduction band of TiO2 followed by intramolecular electron transfer from the dinuclear ${{\rm Ru}{{{\rm II}{\rm \char44}{\rm III}\hfill \atop 2\hfill}}}$ moiety to photogenerated RuIII was observed. The resulting long‐lived ${{\rm Ru}{{{\rm III}{\rm \char44}{\rm III}\hfill \atop 2\hfill}}}$ state decays on the millisecond timescale.
Reductive Coupling of Allylic Esters with Carbonyl Compounds Mediated by the Mischmetall/[SmI2/Pd0cat.′]cat. System
Authors: Médégan Sédami , Hélion Florence , Namy Jean‐Louis
Published: September 2005

The mischmetall/[SmI2/Pd0cat.′]cat. system has been used to mediate the allylation of ketones using a variety of allylic esters (acetates, carbonates and phosphates). Thus, a “two‐stage catalysis” has been carried out using SmI2 and Pd(PPh3)4 in catalytic amounts together with mischmetall (an alloy of the light lanthanides) as a co‐reductant. A catalytic scheme that takes into account previously reported reactions of SmI2/Pd0cat. and mischmetall/SmI2,cat. systems is proposed. It has also been shown that palladium complexes catalyse the addition of organolanthanide species to ketones. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
MPDATA: gauge transformations, limiters and monotonicity
Authors: Margolin L. G. , Shashkov M.
Published: September 2005

MPDATA is a flexible and computationally efficient methodology that has been applied to advection, remapping, and full fluid solvers. In this paper, we extend the fundamental concept, iterated upwind compensation of error, to incorporate a new degree of freedom—that of gauge transformations—with the goal of constructing a monotonicity preserving option for MPDATA. We further augment this scheme by adapting the idea of summing the recursive relations to improve the overall accuracy. This process leads to a theoretical connection of this MPDATA scheme to flux‐limited algorithms. Published in 2005 by John Wiley & Sons, Ltd.
c‐Myc creates an activation loop by transcriptionally repressing its own functional inhibitor, hMad4, in young fibroblasts, a loop lost in replicatively senescent fibroblasts
Authors: Marcotte Richard , Chen Jen Mou , Huard Sylvain , Wang Eugenia
Published: September 2005

c‐Myc transcriptional activity in cells is dampened by the Mad family of transcriptional repressors. The expression of one member, hMad4, is increased in growth‐arrested states such as quiescence or replicative senescence; hMad4 mRNA levels in replicatively senescent fibroblasts are about twice those seen in their young contact‐inhibited quiescent counterparts. Moreover, the repression of hMad4 transcription following serum stimulation observed in quiescent young fibroblasts is lost in senescent cells. This loss results in persistent expression of hMad4, which leads to an inability to switch from an hMad4/Max complex to a c‐Myc/Max complex on selected c‐Myc target genes following serum stimulation. We have located an initiator element (Inr), a candidate for Miz‐1 binding, in the hMad4 promoter. In reporter assays, Miz‐1 enhances reporter GFP expression; this enhancement is inhibited by co‐expressing c‐Myc. Thus hMad4, as does its murine counterpart, contains the Inr element through which Miz‐1 activates its expression; but this action is inhibited in the presence of c‐Myc. This inhibition may explain the down‐regulation of hMad4, corresponding to the up‐regulation of c‐Myc, in young serum‐starved quiescent fibroblasts upon serum stimulation. However, this reciprocal change does not occur in replicatively senescent fibroblasts upon serum stimulation; instead, hMad4 persists in the presence of high levels of c‐Myc activation. Our results suggest that: (1) replicative senescence‐specific factors may block c‐Myc inhibition of Miz‐1 activation of hMad4 expression; and (2) the continual presence of hMad4 protein may transcriptionally repress selected c‐Myc target genes, whose functions are key to the signaling pathways leading to apoptosis inhibition and permanent exit of cell cycle traverse in normal human fibroblasts. J. Cell. Biochem. © 2005 Wiley‐Liss, Inc.
Translating the histone code into leukemia
Authors: Linggi Bryan E. , Brandt Stephen J. , Sun Zu‐Wen , Hiebert Scott W.
Published: September 2005

The “histone code” is comprised of the covalent modifications of histone tails that function to regulate gene transcription. The post‐translational modifications that occur in histones within the regulatory regions of genes include acetylation, methylation, phosphorylation, ubiquitination, sumoylation, and ADP‐ribosylation. These modifications serve to alter chromatin structure and accessibility, and to act as docking sites for transcription factors or other histone modifying enzymes. Several of the factors that are disrupted by chromosomal translocations associated with hematological malignancies can alter the histone code in a gene‐specific manner. Here, we discuss how the histone code may be disrupted by chromosomal translocations, either directly by altering the activity of histone modifying enzymes, or indirectly by recruitment of this type of enzyme by oncogenic transcription factors. These alterations in the histone code may alter gene expression pattern to set the stage for leukemogenesis. J. Cell. Biochem. © 2005 Wiley‐Liss, Inc.
Increased radiation‐induced apoptosis of Saos2 cells via inhibition of NFκB: A role for c‐Jun N‐terminal kinase
Authors: Eliseev Roman A. , Zuscik Michael J. , Schwarz Edward M. , O'Keefe Regis J. , Drissi Hicham , Rosier Randy N.
Published: September 2005

To elucidate the possible effect of NFκB on radioresistance, we used the osteosarcoma cell line Saos2, stably expressing the NFκB constitutive inhibitor, mIκB (Saos2‐mIκB) or stably transfected with the empty vector (Saos2‐EV). Ionizing radiation induced “intrinsic” apoptosis in Saos2‐mIκB cells but not in Saos2‐EV control cells, with intact NFκB activity. We find as expected, that this NFκB activity was enhanced following irradiation in the Saos2‐EV control cells. On the other hand, inhibition of NFκB signaling in Saos2‐mIκB cells led to the upregulation of the pro‐apoptotic systems, such as Bax protein and c‐Jun N‐terminal Kinase (JNK)/c‐Jun/AP1 signaling. Inhibition of NFκB resulted in decreased expression of the DNA damage protein GADD45β, a known inhibitor of JNK. Subsequently, JNK activation of c‐Jun/AP‐1 proteins increased radiation‐induced apoptosis in these mutants. Radiation‐induced apoptosis in Saos2‐mIκB cells was inhibited by the JNK specific inhibitor SP600125 as well as by Bcl‐2 over‐expression. Furthermore, release of cytochrome‐c from mitochondria was increased and caspase‐9 and ‐3 were activated following irradiation in Saos2‐mIκB cells. Antisense inhibition of GADD45β in Saos2‐EV cells significantly enhanced apoptosis following irradiation. Our results demonstrate that radioresistance of Saos2 osteosarcoma cells is due to NFκB‐mediated inhibition of JNK. Our study brings new insight into the mechanisms underlying radiation‐induced apoptosis of osteosarcoma, and may lead to development of new therapeutic strategies against osteosarcoma. J. Cell. Biochem. © 2005 Wiley‐Liss, Inc.
Glycoprotein contributions to mammary gland and mammary tumor structure and function: Roles of adherens junctions, ErbBs and membrane MUCs
Authors: Carraway Kermit L. , Ramsauer Victoria P. , Carothers Carraway Coralie A.
Published: September 2005

Mammary function is dependent on its three‐dimensional organization, which is established and maintained by cell adhesive junctions linked through the membrane to the cell cytoskeleton. These junctions serve not only as structural elements, but also function as initiators and integrators of cell signals. In this review we discuss three types of glycoproteins whose interactions impinge on the function of mammary cell–cell junctions, cadherins, ErbB receptor tyrosine kinases and membrane mucins, as a microcosm of events regulating mammary cell behaviors. Actions of these components are integrated by the critical signaling element β‐catenin. When functioning properly, these glycoproteins, β‐catenin and associated signaling pathways mesh into a highly structured program for development and function of the gland. However, disruption or dysfunction of these glycoproteins or the signaling elements can lead to disorganization of the epithelia and ultimately to neoplasia. J. Cell. Biochem. © 2005 Wiley‐Liss, Inc.
Mechanotransduction in endothelial cell migration
Authors: Li Song , Huang Ngan F. , Hsu Steven
Published: September 2005

The migration of endothelial cells (ECs) plays an important role in vascular remodeling and regeneration. EC migration can be regulated by different mechanisms such as chemotaxis, haptotaxis, and mechanotaxis. This review will focus on fluid shear stress‐induced mechanotransduction during EC migration. EC migration and mechanotransduction can be modulated by cytoskeleton, cell surface receptors such as integrins and proteoglycans, the chemical and physical properties of extracellular matrix (ECM) and cell–cell adhesions. The shear stress applied on the luminal surface of ECs can be sensed by cell membrane and associated receptor and transmitted throughout the cell to cell–ECM adhesions and cell–cell adhesions. As a result, shear stress induces directional migration of ECs by promoting lamellipodial protrusion and the formation of focal adhesions (FAs) at the front in the flow direction and the disassembly of FAs at the rear. Persistent EC migration in the flow direction can be driven by polarized activation of signaling molecules and the positive feedback loops constituted by Rho GTPases, cytoskeleton, and FAs at the leading edge. Furthermore, shear stress‐induced EC migration can overcome the haptotaxis of ECs. Given the hemodynamic environment of the vascular system, mechanotransduction during EC migration has a significant impact on vascular development, angiogenesis, and vascular wound healing. J. Cell. Biochem. © 2005 Wiley‐Liss, Inc.
Aminoacyl‐tRNA synthetase‐interacting multi‐functional protein, p43, is imported to endothelial cells via lipid rafts
Authors: Yi Jae‐Sung , Lee Ji‐Yeon , Chi Sung‐Gil , Kim Ji‐Hyun , Park Sang Gyu , Kim Sunghoon , Ko Young‐Gyu
Published: September 2005

An aminoacyl‐tRNA synthetase subunit, p43, was previously demonstrated to be released from mammalian cells, and to function as an extracellular regulator of both angiogenesis and inflammatory responses (Ko et al., [2001] J Biol Chem, 276; 23028; Park et al.[2002], J Biol Chem 277; 45243). Here, we report that p43 is internalized to the endothelial cells via lipid rafts. Exogenous p43 was co‐localized on bovine aorta endothelial cells with cholera toxin B (CTB), which binds to cholesterol‐enriched lipid rafts. The p43 was rapidly internalized to the cells, as early as 5 min after binding to the surfaces of the cells. p43 bound to the isolated lipid rafts, and its interaction with the lipid rafts, was prevented by high salt content, but not by detergent. This suggests that ionic bonds are involved in the molecular association of p43 with the lipid rafts. Taken together, we conclude that p43 binds to the endothelial cell surface via lipid rafts. J. Cell. Biochem. © 2005 Wiley‐Liss, Inc.
Recognition in action: DNA mimicry
Authors: Goodsell David S.
Published: September 2005

Proteins that mimic DNA present a surface that is similar in shape and chemical character to the DNA double helix. These DNA mimics bind to DNA‐binding proteins, taking the place of DNA. Natural DNA mimics play roles in genetic regulation and defense. Copyright © 2005 John Wiley & Sons, Ltd.
Synthesis of novel core‐crosslinked graft copolymers from crosslinked poly(mercapto‐thiourethane)
Authors: Ochiai Bungo , Endo Takeshi
Published: September 2005

Crosslinked poly(mercapto‐thiourethane) was employed as a precursor for graft copolymer synthesis. The crosslinked stem polymer (1) was easily prepared by polyaddition of a bifunctional dithiocarbonate and piperazine under air atmosphere via oxidative coupling of mercapto group. Polymerization of styrene and methyl methacrylate in the presence of 1 yielded the corresponding crosslinked graft copolymers with high grafting weight percentages (>1800%). © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5097–5102, 2005
A systems biology approach to genetic studies of complex diseases
Authors: Xiong Momiao , Feghali-Bostwick Carol A. , Arnett Frank C , Zhou Xiaodong
Published: September 2005

Revealing mechanisms underlying complex diseases poses great challenges to biologists. The traditional linkage and linkage disequilibrium analysis that have been successful in the identification of genes responsible for Mendelian traits, however, have not led to similar success in discovering genes influencing the development of complex diseases. Emerging functional genomic and proteomic (‘omic’) resources and technologies provide great opportunities to develop new methods for systematic identification of genes underlying complex diseases. In this report, we propose a systems biology approach, which integrates omic data, to find genes responsible for complex diseases. This approach consists of five steps: (1) generate a set of candidate genes using gene–gene interaction data sets; (2) reconstruct a genetic network with the set of candidate genes from gene expression data; (3) identify differentially regulated genes between normal and abnormal samples in the network; (4) validate regulatory relationship between the genes in the network by perturbing the network using RNAi and monitoring the response using RT‐PCR; and (5) genotype the differentially regulated genes and test their association with the diseases by direct association studies. To prove the concept in principle, the proposed approach is applied to genetic studies of the autoimmune disease scleroderma or systemic sclerosis.
Heat-induced and other chemical changes in commercial UHT milks
Authors: Elliott Anthony J , Datta Nivedita , Amenu Boka , Deeth Hilton C
Published: September 2005

The properties of commercial directly and indirectly heated UHT milks, both after heating and during storage at room temperature for 24 weeks, were studied. Thermally induced changes were examined by changes in lactulose, furosine and acid-soluble whey proteins. The results confirmed previous reports that directly heated UHT milks suffer less heat damage than indirectly heated milk. During storage, furosine increased and bovine serum albumin in directly heat-treated milks decreased significantly. The changes in lactulose, α-lactalbumin and β-lactoglobulin were not statistically significant. The data suggest that heat treatment indicators should be measured as soon as possible after processing to avoid any misinterpretations of the intensity of the heat treatment.
Molecular identification and typing of lactobacilli isolated from kefir grains
Authors: Delfederico Lucrecia , Hollmann Axel , Martínez Mariano , Iglesias N. Gabriel , De Antoni Graciela , Semorile Liliana
Published: September 2005

Seventeen heterofermentative lactobacilli isolated from kefir grains were characterized by molecular methods. Bacterial isolates were identified by amplification of 16S rRNA gene and analysis by Amplified Ribosomal DNA Restriction Analysis (ARDRA), using the restriction enzymes Hae III, Dde I, and Hinf I. ARDRA analysis of lactobacilli isolates showed, for each enzyme used, a same banding pattern between the heterofermentative lactobacilli and the reference strains Lactobacillus kefir JCM 5818 and Lb. kefir ATCC 8007. Other reference lactobacilli and one homofermentative isolate showed differences in at least one of these patterns. The 16S-23S rRNA spacer region was also used to discriminate the bacterial isolates at the species level. The data obtained from the analysis of spacer region confirmed that sequencing of this genome region is a good tool for a reliable identification of members of Lb. kefir species. Genotyping of isolates was performed by Random Amplified Polymorphic DNA (RAPD-PCR) analysis using M13, Coc, ERIC-2 and 1254 primers. Patterns obtained allowed the differentiation of isolates in three groups. The three clusters showed by RAPD-PCR analysis could be correlated with at least three different strains of Lb. kefir species in the group of heterofermentative lactobacilli isolates obtained from Argentinian kefir grains.
Kinetics of changes in plasmin activity and proteolysis on heating milk
Authors: Crudden Anthony , Oliveira Jorge C , Kelly Alan L
Published: September 2005

Heat-induced inactivation of bovine plasmin, denaturation of β-lactoglobulin (β-lg), the interactions between both species and casein micelles and the subsequent net effect on proteolysis of β-casein was studied in a model system consisting of phosphocasein and β-lg in synthetic milk ultrafiltrate. The inactivation of plasmin and denaturation of β-lg were first order reactions, with the rate of inactivation of plasmin being greater than the rate of denaturation of β-lg. The predominant mechanism involved in the denaturation of plasmin in the temperature range 65–80 °C was its interaction with β-lg (kr at 60 °C, 0·0526; Ea, 176 KJ/mol). At the point of complete inactivation of plasmin ~45% of the β-lg remained undenatured. Thermal inactivation of plasmin through other mechanisms was negligible. The association of β-lg with the casein micelles at 60 °C had a rate constant of 3·71×10−5 min−1 and an Ea of 259 KJ/mol; thermal denaturation of β-lg was of much less importance, with a rate constant at 60 °C of the order of 1×10−10 min−1 and an Ea of 250 KJ/mol. On denaturation of all β-lg in the system, a maximum of ~55% was associated with the casein micelles. The effect of heating on the subsequent hydrolysis of β-casein indicated that the level of plasmin activity was the most important factor affecting proteolysis, while the interaction of β-lg with the casein micelles had limited effect. Overall, thermal stability of plasmin in milk is very much dependent upon its interaction with β-lg.
designing sound in public space in australia: a comparative study based on the australian sound design project's online gallery and database
Authors: bandt ros
Published: September 2005

the purpose of this paper is to articulate some of the ways in which australian sound practitioners are already designing sound in the public domain so that current trends and practices can be examined, compared and contrasted. this paper interrogates the new hybrid art form, public sound art, and the design processes associated with it as it occurs in public space in australia. the right to quiet has been defined as a public commons (franklin 1993). public space in australia is becoming increasingly sound designed. this article investigates the variety of approaches by sound artists and practitioners who have installed in public space through a representative sample of works drawn from the australian sound design project's online gallery and article, http://www.sounddesign.unimelb.edu.au, a site dedicated to the multimedia publishing of diverse sound designs installed in public space in australia, as well as its international outreach hearing place. works include permanent public and ephemeral sculptures, time-dense computerised sound installations, museum designs, exhibits in airports, art galleries, car parks, digital and interactive media exhibitions, and real-time virtual habitats on and off the web. the degree of interactivity in the sound-designed artworks varies greatly from work to work. stylistic features and design processes are identified in each work and compared and contrasted as a basis for examining the characteristics of the genre as a whole and its impact on the soundscape now and in the future.
the memory machine: sound and memory at the british museum
Authors: lane cathy , parry nye
Published: September 2005

the memory machine is a context-, people- and site-specific interactive sound installation. it has been developed as a collaboration between two composers, cathy lane and nye parry, who share an interest in sound, oral history, and memory. the memory machine is an ongoing project which, most recently, was part of the british museum's 250th anniversary exhibition entitled the museum of the mind; art and memory in world cultures.

this paper discusses the background and ideas behind the memory machine within the context of the composers' work. the development of the project in collaboration with the british museum is described and an evaluation of some of the issues around the public exhibition of the piece is given as well as a full technical description of the different elements of the installation.
Use of multiproxy records on the Agulhas Ridge, Southern Ocean (Ocean Drilling Project Leg 177, Site 1090) to investigate sub‐Antarctic hydrography from the Oligocene to the early Miocene
Authors: Anderson L. D. , Delaney M. L.
Published: September 2005

Ocean Drilling Program (ODP) Site 1090, on the Agulhas Ridge in the South Atlantic sector of the Southern Ocean, is ideally located to capture changes in Southern Ocean circulation patterns. Using samples taken from cored sediments, we construct multiproxy records of productivity (biogenic barium (Baex), opal, and CaCO3 mass accumulation rates (MARs)), nutrient and organic carbon burial (reactive phosphorus (Pr) MARs), and redox conditions (U and Mn enrichments) to investigate hydrographic conditions associated with climatic shifts from the Oligocene through the early Miocene. Orbitally induced cyclicity in U and Mn enrichments (100 kyr) suggests shifts in deepwater characteristics. However, CaCO3 dissolution coincident with low U and Mn enrichments does not indicate low‐oxygen, corrosive waters similar to modern conditions. These observations indicate that a well‐developed “modern‐type” Antarctic Circumpolar Current (ACC) did not yet exist over the period from 30 to 20 Ma, with two potential consequences: The Southern Ocean was not functioning as a silica trap, permitting a broader distribution of silica that may have facilitated organic carbon burial in the ocean in general, and the lack of a deeply mixing ACC may have facilitated organic carbon burial in the Southern Ocean. Both the relative (high opal MARs coincident with low CaCO3 MARs) and absolute (high Pr MARs) burial of organic carbon suggest a powerful mechanism for pCO2 drawdown.
Laser pulse reflectance of the ocean surface from the GLAS satellite lidar
Authors: Lancaster Redgie S. , Spinhirne James D. , Palm Stephen P.
Published: September 2005

The world's oceans can potentially be used as an extended target for achieving a radiometric calibration of space borne lidar if the reflective properties of the surface can be accurately predicted from available environmental data such as wind speed. To test current understanding of ocean reflectance we compare surface pulse returns measured with the 1064 nm altimetry channel of the Geoscience Laser Altimeter System (GLAS) on the Ice, Cloud and land Elevation Satellite (ICESat) with the predictions of near‐IR reflectance from current ocean models. Measurements of wind speed retrieved from the SeaWinds database of the QuikSCAT satellite provide the model input. We find that while ocean models do not provide a full description of the nadir lidar observations this calibration technique yields a precision that exceeds that accomplished using White Sands as a target and that does not require the coordination that accompanies specialized calibration experiments.
Comment on “Gradient-based direct normal-mode analysis” [J. Chem. Phys. 122, 184106 (2005)]
Authors: Reiher Markus , Neugebauer Johannes
Published: September 2005

Kaledin’s very recently described efficient algorithm [J. Chem. Phys. 122, 184106 (2005)] for the direct gradient-based calculation of normal modes is identical to the mode-tracking protocol, which we have published two years earlier. The Comment discusses this aspect, revisits the features of the mode-tracking algorithm, and makes additional references to earlier work by other groups.
Atomic-level strain-relieving mechanism and local electronic structure of a wetting film
Authors: Kim Tae-Hwan , Seo Jungpil , Choi Byoung-Young , Song Young Jae , Choi Jehyuk , Kuk Young , Kahng Se-Jong
Published: September 2005

The strain-relieving mechanism and local electronic density of states of a wetting film, was studied in the Ag∕W system using scanning tunneling microscopy and spectroscopy. In the Ag wetting film, a periodic bright ridge structure was observed along the two equivalent directions, relieving mixed compressive-tensile strain. Two unoccupied electronic states were observed between the ridges, while the other two occupied electronic states were observed at the ridges. The Ag atoms occupying the bridge sites contribute to relieve the elastic strain and to induce the occupied electronic states.
Confocal microphotoluminescence of InGaN-based light-emitting diodes
Authors: Okamoto Koichi , Kaneta Akio , Kawakami Yoichi , Fujita Shigeo , Choi Jungkwon , Terazima Masahide , Mukai Takashi
Published: September 2005

Spatially resolved photoluminescence (PL) of InGaN∕GaN∕AlGaN-based quantum-well-structured light-emitting diodes (LEDs) with a yellow-green light (530nm) and an amber light (600nm) was measured by using confocal microscopy. Submicron-scale spatial inhomogeneities of both PL intensities and spectra were found in confocal micro-PL images. We also found clear correlations between PL intensities and peak wavelength for both LEDs. Such correlations for yellow-green and amber LEDs were different from the reported correlations for blue or green LEDs. This discrepancy should be due to different diffusion, localization, and recombination dynamics of electron-hole pairs generated in InGaN active layers, and should be a very important property for influencing the optical properties of LEDs. In order to explain the results, we proposed a possible carrier dynamics model based on the carrier localization and partial reduction of the quantum confinement Stark effect depending on an indium composition in InGaN active layers. By using this model, we also considered the origin of the reduction of the emission efficiencies with a longer emission wavelength of InGaN LEDs with high indium composition.
Kinetics driving high-density chlorine plasmas
Authors: Stafford L. , Margot J. , Vidal F. , Chaker M. , Giroux K. , Poirier J.-S. , Quintal-Léonard A. , Saussac J.
Published: September 2005

A simple fluid model was developed in order to investigate the driving kinetics of neutral and charged species in high-density chlorine plasmas. It was found that the dissociation degree of Cl2 molecules is directly linked to the power balance of the discharge which controls the electron density. The model was also used to identify those reactions that could be neglected in the particle balance of charged species and those that must be included. Our results further indicate that diffusion losses need to be considered up to a pressure that depends on magnetic-field intensity and reactor aspect ratio. Finally, it is shown that the dominant charged carriers are linked to the dissociation level of Cl2 molecules.
The inelastic behavior and failure of dense glass under shock loading to 15GPa
Authors: Radford D. D.
Published: September 2005

The in-material longitudinal and lateral stress histories in an extra-dense, silica-based glass have been measured at impact pressures well above the Hugoniot elastic limit using embedded manganin stress gauges during plate impact experiments. The measurements of longitudinal stress extend the current data and are used to provide an extensive principal Hugoniot for the material. The lateral stress measurements obtained at high impact pressures show the pressure-dependent nature of the failure process, consistent with previous studies on dense glasses. The longitudinal and lateral data obtained are used to determine the shear strength versus time history during high-pressure loading. These data in conjunction with high-speed photographic records provide insight into the inelastic response and evolution of failure in brittle materials during shock loading.
Gettering of copper to hydrogen-induced cavities in multicrystalline silicon
Authors: Kinomura A. , Horino Y. , Nakano Y. , Williams J. S.
Published: September 2005

The gettering properties of hydrogen-induced cavities have been examined for Cu impurity atoms inherent in multicrystalline Si. Initial areal densities of Cu atoms in the multicrystalline samples were in the range of (3–5)×1013cm−2, below the level that would provide a complete monolayer coverage of the internal surfaces of the cavities. Samples were first implanted with hydrogen and then annealed at 750 or 850°C for 1h to form cavities and induce subsequent gettering. Neutron activation analysis with chemical etching of the samples indicated that more than 90% of Cu atoms could be removed from the entire wafer by cavity gettering for both of the annealing temperatures.
Large scale image projection setup for observation of flocculation in heavy oil∕water emulsions
Authors: Da Costa Germán
Published: September 2005

A heavy oil-in-water emulsion is heated by a continuous wave laser beam, thus producing an ascending thermoconvective liquid flow. Once at the open free surface the oil particles are directly heated by the incoming laser beam, which gives rise to flocculation and eventually to coalescence. A bright, enlarged image of the heated region is formed in a projection screen using the backscattered light of their own laser beam. The device thus allows direct observation and high speed photographic recording of the flocculation process as a function of the sample temperature, which is monitored by means of a thermographic camera.
Sub-10 fs, multimillijoule laser system
Authors: Oishi Yu , Suda Akira , Midorikawa Katsumi , Kannari Fumihiko
Published: September 2005

An intense sub-10 fs Ti:sapphire laser system has been developed for investigating ultrafast nonlinear phenomena. Sub-10 fs, multimillijoule pulses were obtained from a laser system consisting of a conventional chirped-pulse amplifier and a subsequent pressure-gradient hollow fiber pulse compressor, without any additional amplification. We describe the design and performance of the laser system together with high-order harmonic generation in the sub-10 fs regime as an example of one of the applications that were made possible by using this laser system.
TheShigella flexnerieffector OspG interferes with innate immune responses by targeting ubiquitin-conjugating enzymes
Authors: Kim Dong Wook , Lenzen Gerlinde , Page Anne-Laure , Legrain Pierre , Sansonetti Philippe J. , Parsot Claude
Published: September 2005

Bacteria ofShigellaspp. are responsible for shigellosis in humans. They use a type III secretion system to inject effector proteins into host cells and induce their entry into epithelial cells or trigger apoptosis in macrophages. We present evidence that the effector OspG is a protein kinase that binds various ubiquitinylated ubiquitin-conjugating enzymes, including UbcH5, which belongs to the stem cell factor SCFβ-TrCPcomplex promoting ubiquitination of phosphorylated inhibitor of NF-κB type α (phospho-IκBα). Transfection experiments indicated that OspG can prevent phospho-IκBα degradation and NF-κB activation induced by TNF-α stimulation. Infection of epithelial cells by theS.flexneriwild-type strain, but not anospGmutant, led to accumulation of phospho-IκBα, consistent with OspG inhibiting SCFβ-TrCPactivity. Upon infection of ileal loops in rabbits, theospGmutant induced a stronger inflammatory response than the wild-type strain. This finding indicates that OspG negatively controls the host innate response induced byS.flexneriupon invasion of the epithelium.
The effects of diet on circulating sex hormone levels in men
Authors: Allen Naomi E , Key Timothy J
Published: September 2005

There is considerable epidemiological evidence that a Western-style diet may increase the risk of certain hormone-dependent conditions in men via its effects on hormone metabolism. Experimental evidence also suggests that dietary factors may exert subtle effects on hormone metabolism. Here we review the clinical and epidemiological evidence that diet is associated with circulating sex hormone levels in men. In comparison with factors such as age and BMI, nutrients do not appear to be strong determinants of sex hormone levels. Dietary intervention studies have not shown that a change in dietary fat and/or dietary fibre intake is associated with changes in circulating sex hormone concentrations over the short term. The data on the effects of dietary phyto-oestrogens on sex hormone levels in men are too limited for conclusions to be drawn. Observational studies between men from different dietary groups have shown that a vegan diet is associated with small but significant increases in sex-hormone-binding globulin and testosterone concentrations in comparison with meat-eaters. However, these studies have not demonstrated that variations in dietary composition have any long-term important effects on circulating bioavailable sex hormone levels in men. This lack of effect may be partly explained by the body's negative feedback mechanism, which balances out small changes in androgen metabolism in order to maintain a constant level of circulating bioavailable androgens. It appears, therefore, that future studies should look for dietary effects on the feedback mechanism itself, or on the metabolism of androgens within the target tissues.
Nutritional ergogenic aids and exercise performance
Authors: Maughan R. J.
Published: September 2005

The use of nutritional supplements in sport is widespread and few serious athletes do not, at some stage in their career, succumb to the temptation to experiment with one or more nutritional supplements. Nutritional ergogenic aids are aimed primarily at enhancing performance (either by affecting energy metabolism or by an effect on the central nervous system), at increasing lean body mass or muscle mass by stimulation of protein synthesis and at reducing body fat content. Although not strictly ergogenic (i.e. capable of enhancing work performance), supplements aimed at increasing resistance to infection and improving general health are seen by athletes as important in reducing the interruptions to training that minor illness and infection can cause. Creatine is perhaps the most widely used supplement in sport at the moment. Supplementation can increase muscle creatine phosphate levels and, although not all published studies show positive results, there is much evidence that performance of short-term high-intensity exercise can be improved by supplementation. Ingestion of large doses of bicarbonate can enhance performance of exercise where metabolic acidosis may be a limiting factor, but there is a significant risk of adverse gastrointestinal side effects. Caffeine can also improve performance, in part by a stimulation of fatty acid mobilization and sparing of the body's limited carbohydrate stores, but also via direct effects on muscle and possibly by central nervous system effects on the perception of effort and fatigue. Carnitine plays an essential role in fatty acid oxidation in muscle but, although supplements are used by athletes, there is no good evidence of a beneficial effect of supplementation. None of these products contravenes the International Olympic Committee regulations on doping in sports, although caffeine is not permitted above a urine concentration of 12 mg/l. Supplementation is particularly prevalent among strength and power athletes, where an increase in muscle mass can benefit performance. Protein supplements have not been shown to be effective except in those rare cases where the dietary protein intake is otherwise inadequate. Individual amino acids, especially ornithine, arginine and glutamine, are also commonly used, but their benefit is not supported by documented evidence. Cr and hydroxymethylbutyrate are also used by strength athletes, but again there are no well-controlled studies to provide evidence of a beneficial effect. Athletes use a wide variety of supplements aimed at improving or maintaining general health and vitamin and mineral supplementation is widespread. There is a theoretical basis, and limited evidence, to support the use of antioxidant vitamins and glutamine during periods of intensive training, but further evidence is required before the use of these supplements can be recommended.