bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sensitivity to DNA Damage Is a Common Component of Hormone-Based Strategies for Protection of the Mammary Gland
Authors: Tu Yifan , Jerry D. Joseph , Pazik Brooke , Smith Schneider Sallie 
Published: September 2005

AbstractAn early full-term pregnancy significantly reduces the risk of getting breast cancer in women. In animals, this protection can be mimicked by a short-term exposure to physiologic doses of estrogen plus progesterone. Sensitization of p53 and up-regulation of transforming growth factor β are believed to be important aspects of the mechanism by which protection is imparted. Little is known, however, about the use of this pathway in response to other chemopreventive agents. In this article, we investigated the ability of retinoids, such as 9-cis retinoic acid, all-trans retinoic acid, and N-4-hydroxyphenylretinamide (4-HPR), to sensitize the ductal epithelial cells of virgin mammary glands to DNA damage responses. Using a whole-organ culture system, we observed enhanced cell death in response to γ-irradiation in the virgin tissues treated with retinoids for 72 hours. These retinoids were partially dependent on p53 and transforming growth factor β to exert their radiosensitizing effects. However, 4-HPR seemed to sensitize other cells or activate these pathways in a different manner as costimulation with ovarian hormones and 4-HPR was additive, whereas coculture of ovarian hormones and the natural retinoids did not increase amount of death. Taken together, these data suggest that sensitization of the mammary epithelium to p53-dependent apoptosis is a common pathway, which is engaged by retinoids as well as ovarian hormones.
Lipopolysaccharide Prevents Doxorubicin-Induced Apoptosis in RAW 264.7 Macrophage Cells by Inhibiting p53 Activation
Authors: Hassan Ferdaus , Islam Shamima , Mu Mya Mya , Ito Hiroyasu , Koide Naoki , Mori Isamu , Yoshida Tomoaki , Yokochi Takashi 
Published: September 2005

Abstract
The effect of lipopolysaccharide on doxorubicin-induced cell death was studied by using mouse RAW 264.7 macrophage cells. Pretreatment with lipopolysaccharide at 10 ng/mL prevented doxorubicin-induced cell death and the inhibition was roughly dependent on the concentration of lipopolysaccharide. Posttreatment with lipopolysaccharide for 1 hour also prevented doxorubicin-induced cell death. Lipopolysaccharide inhibited DNA fragmentation and caspase-3 activation in doxorubicin-treated RAW 264.7 cells, suggesting the prevention of doxorubicin-induced apoptosis. Lipopolysaccharide did not significantly inhibit doxorubicin-induced DNA damage detected by single-cell gel electrophoresis (comet) assay. Lipopolysaccharide definitely inhibited the stabilization and nuclear translocation of p53 in doxorubicin-treated RAW 264.7 cells. Lipopolysaccharide, as well as being an inhibitor of p53, abolished doxorubicin-induced apoptosis. Therefore, p53 was suggested to play a pivotal role in the prevention of doxorubicin-induced apoptosis in RAW 264.7 cells by lipopolysaccharide.
Who Comes First? The Role of the Prefrontal and Parietal Cortex in Cognitive Control
Authors: Brass Marcel , Ullsperger Markus , Knoesche Thomas R. , Cramon D. Yves von , Phillips Natalie A. 
Published: September 2005

Abstract
Cognitive control processes enable us to adjust our behavior to changing environmental demands. Although neuropsychological studies suggest that the critical cortical region for cognitive control is the prefrontal cortex, neuro-imaging studies have emphasized the interplay of prefrontal and parietal cortices. This raises the fundamental question about the different contributions of prefrontal and parietal areas in cognitive control. It was assumed that the prefrontal cortex biases processing in posterior brain regions. This assumption leads to the hypothesis that neural activity in the prefrontal cortex should precede parietal activity in cognitive control. The present study tested this assumption by combining results from functional magnetic resonance imaging (fMRI) providing high spatial resolution and event-related potentials (ERPs) to gain high temporal resolution. We collected ERP data using a modified task-switching paradigm. In this paradigm, a situation where the same task was indicated by two different cues was compared with a situation where two cues indicated different tasks. Only the latter condition required updating of the task set. Task-set updating was associated with a midline negative ERP deflection peaking around 470 msec. We placed dipoles in regions activated in a previous fMRI study that used the same paradigm (left inferior frontal junction, right inferior frontal gyrus, right parietal cortex) and fitted their directions and magnitudes to the ERP effect. The frontal dipoles contributed to the ERP effect earlier than the parietal dipole, providing support for the view that the prefrontal cortex is involved in updating of general task representations and biases relevant stimulus-response associations in the parietal cortex.
Rule-dependent Activity for Prosaccades and Antisaccades in the Primate Prefrontal Cortex
Authors: Everling Stefan , DeSouza Joseph F. X. 
Published: September 2005

Abstract
Everyday life typically requires behavior that involves far more than simple stimulus-response associations. Environmental cues are often ambiguous and require different actions depending on the situation. The prefrontal cortex (PFC) is thought to be crucial for this flexible control of behavior. An important task that probes this ability is the antisaccade task in which subjects have to suppress a glance towards a suddenly presented peripheral stimulus and instead look away from the stimulus to its mirror location. Here we recorded the activity of PFC neurons in monkeys trained to alternate between blocks of prosaccade and antisaccade trials with no external instruction cues. We found that the activity of many neurons was different between the two tasks during the fixation period before the peripheral stimulus was presented. These differences were already present on the first correct trials after a task switch. The activity of these neurons also discriminated between correct responses and errors. We hypothesize that the PFC provides bias signals to saccade-related areas that are necessary to preset the oculomotor system for different tasks.
Immune sensitization of equine bronchus: glutathione, IL-1β expression and tissue responsiveness
Authors: Matera MG , Calzetta L , Peli A , Scagliarini A , Matera C , Cazzola M 
Published: September 2005

AbstractBackgroundIncreasing clinical epidemiological and experimental evidence indicates that excess of production of reactive oxygen free radicals (ROS) induced by an oxidative stress is involved in the pathogenesis of a number of human airway disorders, as well as equine recurrent airway obstruction. Free-radicals modulate the activation of transcription factors, such as nuclear factor-(NF)-κB and activator protein (AP)-1, in several different cells. This activation leads to expression of many pro-inflammatory cytokines, including interleukin (IL)-1β. We have hypothesized that equine airway sensitization might induce an oxidative stress and increase the ROS production, which in turn might enhance a production of IL-1β and airway hyperresponsiveness.MethodsWe have examined the effect of passive sensitization on IL-1β mRNA expression and electrical field stimulation (EFS)-induced contraction in equine isolated bronchi, and the potential interference of reduced-glutathione (GSH), an antioxidant, with these responses. Bronchi passively sensitized with serum from animals suffering from heaves and having high total level of IgE, and control tissues, either pretreated or not with GSH (100 μM), were used to quantify IL-1β mRNA. Other tissues were used to study the effect of EFS (3–10–25 Hz).ResultsMean IL-1β mRNA expression was higher in passively sensitized than in control rings. GSH significantly (p< 0.05) reduced the IL-1β mRNA expression only in passively sensitized bronchi. ELF induced a frequency-dependent contraction in both non-sensitized and passively sensitized tissues, with a significantly greater response always observed in sensitized tissues. GSH did not modify the EFS-induced contraction in non-sensitized bronchi, but significantly (p< 0.05) decreased it in passively sensitized tissues.ConclusionOur data indicate that the passive sensitization of equine bronchi induces inflammation and hyperresponsiveness. These effects might be due to an oxidative stress because a pretreatment with GSH decreased the increased IL-1β mRNA expression and responsiveness to EFS of passively sensitized bronchi.
Averaged Trajectory of Random Walk Fluctuations Having a Fixed Lifetime and its Application in Characterization of Simplest Chemical Equilibrium
Authors: Šolc M. 
Published: September 2005

Abstract
Recently, we found that for a simple first-order reaction having equilibrium constant equal to 1, the amplitudes of equilibrium fluctuations can be, on the discrete time scale (scale of reaction events), satisfactorily described using the random walk approximation for the distribution and mean amplitude of fluctuation having the fixed lifetime 2r reaction events. Below, we propose another characterization of fluctuations in the random walk introducing an averaged trajectory of fluctuations and suggest another formula for the mean amplitude of fluctuations having a fixed length. The results are used in characterization of equilibrium fluctuations of first order reversible chemical reaction having the equilibrium constant equal to 1.
Device Physics of Solution‐Processed Organic Field‐Effect Transistors
Authors: Sirringhaus H. 
Published: September 2005

AbstractField‐effect transistors based on solution‐processible organic semiconductors have experienced impressive improvements in both performance and reliability in recent years, and printing‐based manufacturing processes for integrated transistor circuits are being developed to realize low‐cost, large‐area electronic products on flexible substrates. This article reviews the materials, charge‐transport, and device physics of solution‐processed organic field‐effect transistors, focusing in particular on the physics of the active semiconductor/dielectric interface. Issues such as the relationship between microstructure and charge transport, the critical role of the gate dielectric, the influence of polaronic relaxation and disorder effects on charge transport, charge‐injection mechanisms, and the current understanding of mechanisms for charge trapping are reviewed. Many interesting questions on how the molecular and electronic structures and the presence of defects at organic/organic heterointerfaces influence the device performance and stability remain to be explored.
Substoichiometric conversion of biomass and solid wastes to energy in packed beds
Authors: Yang Yao Bin , Sharifi Vida Nasserzadeh , Swithenbank Jim 
Published: September 2005

AbstractBiomass and municipal solid wastes are two of the sustainable energy resources. Countercurrent, substoichiometric conversion of these fuels into energy in packed beds has the benefits of lower tar and dust carryover in flue gases, and therefore gas‐treatment procedures can be simplified and the running cost is reduced. In this paper, mathematical simulation is performed on a large‐scale plant furnace for both municipal solid wastes and biomass fuels in a range of operating conditions. The temperature profile inside the moving packed bed of the same system was measured by an in situ electronic device for the baseline case to partially validate the simulation results. Mathematical simulation indicates that by using variable grate speed to obtain constant bed height, a typical moving‐bed furnace can achieve over 99% of conversion efficiency with only 40–50% of the normal primary air supply, without loss in throughput; the char conversion rate is significantly lower than the devolatilization rate in the bed and the char conversion process occupies over half of the total bed length, whereas fuel devolatilization occupies only one‐third or more of the bed length. © 2005 American Institute of Chemical Engineers AIChE J, 2006
Formability and accuracy of micropolymer compound with added nanomaterials in microinjection molding
Authors: Huang C. K. , Chiu S. W. 
Published: September 2005

AbstractThe miniaturization of components has been progressing rapidly because of developments in microelectronics, optoelectronics, and biotechnology. Recently, the use of plastic materials with added fillers has become a potential alternative because of their versatility and ease of batch fabrication. This article investigates the formability and accuracy of the polymer with added nanopowders (10–30 nm diameter) during microinjection molding. One mold with four cavities is used to illustrate the filling behavior and accuracy of the microparts. The integrated circuit microfeature illustrates the formability of the polymer with added nanopowders. Experiments show that the shrinkage is significantly reduced when the nanopowder content is increased. The polymer with 30% ZnO nanopowder content shows 58.3% less shrinkage compared to pure polypropylene. One mold with four parts and the microfeature are successfully manufactured using a custom‐made microinjection machine when nanopowders are added to the polymer. However, the microfeature with added fillers, which had a diameter of 10 μm and a length of 10–30 μm, cannot be duplicated through microinjection molding. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1865–1874, 2005
Copolymers of 2‐hydroxyethylmethacrylate and N‐maleoylglycine: Synthesis, characterization, and swelling behavior
Authors: Jeria Manuel , Pizarro Guadalupe del C. , Marambio Oscar G. , Huerta Margarita , Valencia Paulina , Rivas Bernabé L. 
Published: September 2005

AbstractWe synthesized copolymers based on 2‐hydroxyethylmethacrylate and N‐maleoylglycine by varying the monomer feed composition. The copolymers were characterized by Fourier transform infrared spectroscopy, elemental analysis, and thermogravimetry/differential scanning calorimetry as the thermal analysis method. The thermograms showed that the polymers degraded in a single‐stage process. For the hydrogels of poly(2‐hydroxyethylmethacrylate) and poly(2‐hydroxyethylmethacrylate‐co‐N‐maleoylglycine) [poly(HEMA‐co‐MG)], swelling behaviors were investigated by the immersion of the gels in solution at pH's of 3, 5, and 7. The swelling studies were performed with and without ionic strength. The copolymer composition had a significant effect on the equilibrium swelling behavior of poly(HEMA‐co‐MG). With those soluble copolymer fractions, we obtained a low conversion (<30%); the monomer reactivity ratios were estimated by the Kelen–Tüdös linear method. The data indicated that poly(HEMA‐co‐MG) was a random copolymer. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1897–1902, 2005
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

AbstractWe 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

AbstractSince 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

AbstractTwo 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

AbstractHomoleptic 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.