bluuebunny/crossref_metadata_2025_split huggingface dataset:
In vitro and in vivo antitumor effect of 5‐FU combined with piplartine and piperine
Authors: Bezerra Daniel P. , Castro Fernanda O. de , Alves Ana Paula N. N. , Pessoa Cláudia , Moraes Manoel Odorico de , Silveira Edilberto R. , Lima Mary Anne S. , Elmiro Francisca Juliana M. , Alencar Nylane M. N. de , Mesquita Rodney O. , Lima Michael W. , Costa‐Lotufo Letícia V. 
Published: May 2007

AbstractIt has been reported that piplartine and piperine, alkaloid/amide compounds from Piper species, show antitumor activities. In the present paper, the effects of the combination of 5‐fluorouracil (5‐FU) with piplartine or piperine was determined using in vitro and in vivo experimental models. Hematological and biochemical analyses, as well as histopathological and morphological analyses of the tumor and the organs, including liver, spleen and kidney, were performed in order to evaluate the toxicological aspects associated with different treatments. The incubation of tumor cell lines with 5‐FU in the presence of piplartine or piperine produced an increase in growth inhibition, as observed by lower IC50 values for 5‐FU. These effects were also observed in vivo, where the combination with piplartine but not piperine with 5‐FU led to a higher tumor growth inhibition. The results indicated that either piplartine‐ or 5‐FU‐treated animals showed a low inhibition rate when they were used individually at low doses of 28.67% and 47.71%, respectively, but when they were combined at the same dose, the inhibition rate increased significantly to 68.04%. The histopathological analysis showed that the livers and the kidneys of treated animals were only slightly and reversibly affected. Neither the enzymatic activity of transaminases nor the urea levels were significantly modified when compared with the control group. Hematological analysis showed leukopenia after 5‐FU treatment, which was reversed by the combined use of piplartine and piperine. These findings indicate that piplartine may enhance the therapeutic effectiveness of chemotherapeutic drugs, and moreover, this combination could improve immunocompetence hampered by 5‐FU. Copyright © 2007 John Wiley & Sons, Ltd.
Pristimerin induces apoptosis by targeting the proteasome in prostate cancer cells
Authors: Yang Huanjie , Landis‐Piwowar Kristin R. , Lu Dayan , Yuan Ping , Li Lihua , Reddy G. Prem‐Veer , Yuan Xiao , Dou Q. Ping 
Published: May 2007

AbstractPristimerin is a natural product derived from the Celastraceae and Hippocrateaceae families that were used as folk medicines for antiinflammation in ancient times. Although it has been shown that pristimerin induces apoptosis in breast cancer cells, the involved mechanism of action is unknown. The purpose of the current study is to investigate the primary target of pristimerin in human cancer cells, using prostate cancer cells as a working model. Nucleophilic susceptibility and in silico docking studies show that C6 of pristimerin is highly susceptible towards a nucleophilic attack by the hydroxyl group of N‐terminal threonine of the proteasomal chymotrypsin subunit. Consistently, pristimerin potently inhibits the chymotrypsin‐like activity of a purified rabbit 20S proteasome (IC50 2.2 µmol/L) and human prostate cancer 26S proteasome (IC50 3.0 µmol/L). The accumulation of ubiquitinated proteins and three proteasome target proteins, Bax, p27 and IκB‐α, in androgen receptor (AR)‐negative PC‐3 prostate cancer cells supports the conclusion that proteasome inhibition by pristimerin is physiologically functional. This observed proteasome inhibition subsequently led to the induction of apoptotic cell death in a dose‐ and kinetic‐dependent manner. Furthermore, in AR‐positive, androgen‐dependent LNCaP and AR‐positive, androgen‐independent C4‐2B prostate cancer cells, proteasome inhibition by pristimerin results in suppression of AR protein prior to apoptosis. Our data demonstrate, for the first time, that the proteasome is a primary target of pristimerin in prostate cancer cells and inhibition of the proteasomal chymotrypsin‐like activity by pristimerin is responsible for its cancer cell death‐inducing property. J. Cell. Biochem. 103: 234–244, 2008. © 2007 Wiley‐Liss, Inc.
Angiogenesis by transplantation of HIF‐1α modified EPCs into ischemic limbs
Authors: Jiang Meng , Wang Binyao , Wang Changqian , He Ben , Fan Huahua , Guo Taylor B. , Shao Qin , Gao Li , Liu Yan 
Published: May 2007

AbstractHypoxia inducible factor‐1α (HIF‐1α) is a key determinant of oxygen‐dependent gene regulation in angiogenesis. HIF‐1α overexpression may be beneficial in cell therapy of hypoxia‐induced pathophysiological processes, such as ischemic heart disease. To address this issue, human peripheral blood mononuclear cells (PBMNCs) were induced to differentiate into endothelial progenitor cells (EPCs), and then were transfected with either an HIF‐1α‐expressing or a control vector and cultured under normoxia or hypoxia. Hypoxia‐induced HIF‐1α mRNA and protein expression was increased after HIF‐1α transfection. This was accompanied by VEGF mRNA induction and increased VEGF secretion. Hypoxia‐stimulated VEGF mRNA induction was significantly abrogated by HIF‐1α‐specific siRNA. Functional studies showed that HIF‐1α overexpression further promoted hypoxia‐induced EPC differentiation, proliferation and migration. The expressions of endothelial cell markers CD31, VEGFR2 (Flk‐1) and eNOS as well as VEGF and NO secretions were also increased. Furthermore, in an in vivo model of hindlimb ischemia, HIF‐1α‐transfected EPCs homed to the site of ischemia. A higher revascularization potential was also demonstrated by increased capillary density at the injury site. Our results revealed that endothelial progenitor cells ex vivo modification by hypoxia inducible factor‐1α gene transfection is feasible and may offer significant advantages in terms of EPC expansion and treatment efficacy. J. Cell. Biochem. 103: 321–334, 2008. © 2007 Wiley‐Liss, Inc.
Cancer stem cells in leukemia, recent advances
Authors: Zou Gang‐Ming 
Published: May 2007

AbstractThe history of stem cell research was started in the early 1900s in Europe where the researcher realized that various types of blood cells came from a particular “stem cells.” However, it was not until 1963 that the first quantitative description of the self‐renewal activities of transplanted mouse bone marrow cells were documented by Canadian scientist Ernest A McCulloch and James E Till in Toronto. The concept of cancer stem cells has been used over 50 years ago; whereas the strong evidence for the existence of a Cancer Stem Cells was obtained recently. Consequently, there is increasing attention in recent year about cancer stem cells. The findings from recent studies support the concept that stem cells are integral to the development of several forms of human cancer. Changes in stem cell behavior can contribute to tumor formation. Leukemia is a cancer of blood‐forming tissue, including the bone marrow and lymphatic system. Leukemic stem cells represent the cancer stem cells in the leukemia. In this review, we summarize the recent advance in the study of leukemic stem cells. J. Cell. Physiol. 213: 440–444, 2007. © 2007 Wiley‐Liss, Inc.
Microfluidic selection and applications of aptamers
Authors: Mosing Renee K. , Bowser Michael T. 
Published: May 2007

AbstractThe high affinity and specificity of aptamers make them ideal reagents for a wide range of analytical applications. It is not surprising that they are finding application in microfluidics as well. CE has proven to be an efficient technique for isolating aptamers. Aptamers have been used as affinity reagents in CE assays. Aptamer‐based chromatography stationary phases have demonstrated unique selectivities. Possibly the application that holds the highest potential is aptamer microarrays for screening proteomic samples.
Recent applications in nanoliquid chromatography
Authors: Hernández‐Borges Javier , Aturki Zeineb , Rocco Anna , Fanali Salvatore 
Published: May 2007

AbstractSince its first introduction by Karlsson and Novotny in 1988 nano‐LC has emerged as a complementary and/or competitive separation method to conventional HPLC, offering several advantages such as higher efficiency, ability to work with minute sample sizes and lower consumption of mobile phases, and better compatibility with MS, etc. Although its use was not so extended initially, in the last years new and interesting applications have appeared which deserve to be carefully considered. The aim of this review is therefore to provide an updated and critical survey of different nano‐LC applications in analytical chemistry.
PLA Nano‐ and Microparticles for Drug Delivery: An Overview of the Methods of Preparation
Authors: Lassalle Verónica , Ferreira María Luján 
Published: May 2007

AbstractThe controlled release of medicaments remains the most convenient way of drug delivery. Therefore, a wide variety of reports can be found in the open literature dealing with drug delivery systems. In particular, the use of nano‐ and microparticles devices has received special attention during the past two decades. PLA and its copolymers with GA and/or PEG appear as the preferred substrates to fabricate these devices. The methods of fabrication of these particles will be reviewed in this article, describing in detail the experimental variables associated with each one with regard to the influence of them on the performance of the particles as drug carriers. An analysis of the relationship between the method of preparation and the kind of drug to encapsulate is also included. Furthermore, certain issues involved in the addition of other monomeric substrates than lactic acid to the particles formulation as well as novel devices, other than nano‐ and microparticles, will be discussed in the present work considering the published literature available.magnified image
Capturing Relativized Complexity Classes without Order
Authors: Dawar Anuj , Gottlob Georg , Hella Lauri 
Published: May 2007

AbstractWe consider the problem of obtaining logical characterisations of oracle complexity classes. In particular, we consider the complexity classes LOGSPACENP and PTIMENP. For these classes, characterisations are known in terms of NP computable Lindström quantifiers which hold on ordered structures. We show that these characterisations are unlikely to extend to arbitrary (unordered) structures, since this would imply the collapse of certain exponential complexity hierarchies. We also observe, however, that PTIMENP can be characterised in terms of Lindström quantifers (not necessarily NP computable), though it remains open whether this can be done for LOGSPACENP.
Extracting Algorithms from Intuitionistic Proofs
Authors: Ferreira Fernando , Marques António 
Published: May 2007

AbstractThis paper presents a new method ‐ which does not rely on the cut‐elimination theorem ‐ for characterizing the provably total functions of certain intuitionistic subsystems of arithmetic. The new method hinges on a realizability argument within an infinitary language. We illustrate the method for the intuitionistic counterpart of Buss's theory S, and we briefly sketch it for the other levels of bounded arithmetic and for the theory IΣ1.
Games with Unknown Past
Authors: Khoussainov Bakhadyr , Yakhnis Alexander , Yakhnis Vladimir 
Published: May 2007

AbstractWe define a new type of two player game occurring on a tree. The tree may have no root and may have arbitrary degrees of nodes. These games extend the class of games considered by Gurevich‐Harrington in [5]. We prove that in the game one of the players has a winning strategy which depends onfinite bounded information about the pastpart of a play and on future of each play that isisomorphism typesof tree nodes. This result extends further the Gurevich‐Harrington determinacy theorem from [5].
Dynamics of Polymer Networks with Strong Differences in the Viscous Characteristics of their Crosslinks and Strands
Authors: Toshchevikov Vladimir P. , Blumen Alexander , Gotlib Yulii Ya. 
Published: May 2007

AbstractWe study theoretically the relaxation properties of polymer networks, whose monomers and junction sites have different friction parameters (ζ and ζjun, respectively). For this, we focus on topologically regular cubic networks built from “bead‐and‐spring” Rouse chains. Setting σ = ζjun/ζ, we determine analytically both the eigenvalues and the eigenmodes of the model for arbitrary values of σ. This allows us to extend previous approaches (Macromolecules 2000, 33, 6578) which were restricted by the condition σ = 3. We compute the frequency dependent storage, G′(ω), and loss, G″(ω), moduli (which for σ ≫ 3 or σ ≪ 3 display two plateaus and two maxima, respectively) and also the mean‐square displacements of the network junctions and of the beads; these turn out to obey power laws, whose validity ranges depend on σ.magnified image
Self‐Assembly of Heteroarm Star Copolymers – A Monte Carlo Study
Authors: Havránková Jitka , Limpouchová Zuzana , Štěpánek Miroslav , Procházka Karel 
Published: May 2007

AbstractDynamic lattice Monte Carlo simulations on a simple cubic lattice were used to study the association behavior of heteroarm star copolymers with two types of chemically different arms (miktoarm star). The effect of architecture and composition (number and length of arms) on self‐assembly was investigated. Simulations revealed substantial differences between associates formed by linear diblock copolymers and by star copolymers. It was also observed that the length of arms considerably influences the association behavior. Apart from the structural characteristics of the whole associate, the properties of individual stars in associates were also studied. These results provide detailed information on the inner structure of associates.magnified image
Monte Carlo Simulation of Polymer Reactions at Interfaces
Authors: John Andreas , Nagel Jürgen , Heinrich Gert 
Published: May 2007

AbstractAdhesion of immiscible polymers during two‐component injection moulding may be improved by transreactions of properly functionalised components. We performed MC simulations based on the three‐dimensional coarse‐grained bond fluctuation model (BFM) including a thermal interaction potential in $r \leq \sqrt{6}$ with energy $\varepsilon = \pm 0.1\,k_{\rm B} T$ to characterise the behaviour of several selected types of chemical reactions, which are governed by activation energies of EA = 0, 1, 3 and 5 kBT. The consumption of reactive monomers for all the reactions in the time interval below the Rouse time τR exhibits a typical crossover from a kinetic‐controlled to a diffusion‐controlled behaviour and can be described by a bimolecular kinetic ansatz.magnified image
Modelling the Influence of Nanoparticles in the Phase Behaviour of an Epoxy/Polystyrene Mixture, 2
Authors: Figueruelo Juan E. , Gómez Clara M. , Monzó Isidro S. , Abad Concepción , Campos Agustín 
Published: May 2007

AbstractThe influences of nanoparticle size and concentration on the thermodynamic behaviour of epoxy/polystyrene blends are evaluated in the framework of Ginzburg's simple analytical theory. Two approaches have been employed: NPEPO (for particles coated with epoxy groups) and NPFEN (for particles coated with phenyl groups). Using NPEPO, the particles are found to prefer the phase richer in epoxy, whereas the opposite occurs for NPFEN. The particles size significantly influences blend compatibility. When the particle radius Rp is about the same size as the radius of gyration Rg of PS, the compatibility of blends increases with particle concentration, whereas for Rp > Rg, higher particle concentrations do not clearly stabilize the polymeric blends.magnified image
Polymer Distribution Change During Irreversible Depolymerization by Chain‐End Scission
Authors: Tobita Hidetaka 
Published: May 2007

AbstractThe change in polymer distribution during depolymerization in which monomer molecules are severed one by one from the chain ends, is considered. Assuming irreversible depolymerization and equal reactivity of all the chain ends, a general formula to calculate the MWD is proposed. After the removal of monomers severed from the chains, the MWDs of depolymerized polymers always approach the most probable distribution whose PDI is practically equal to 2. It may appear to be counterintuitive, but the average MWs of polymers may increase during chain scission when the initial distribution is broader than the most probable (PDI  >  2). The interpretation of the MWD data of polymers during depolymerization, such as those obtained by GPC, are not straightforward especially for the initial broad MWDs.magnified image
A Review of Modeling of Diffusion Controlled Polymerization Reactions
Authors: Achilias Dimitris S. 
Published: May 2007

AbstractA plethora of models have been developed quantifying the effect of diffusion‐controlled phenomena on polymerization reactions. The most prominent approaches are reviewed here, including innovative ones that have emerged over the last decade. Free‐radical and step‐growth polymerizations are considered in a way to show that similar models have been used in both mechanisms. In free‐radical polymerization the models proposed are subdivided according to their theoretical background into four categories: (i) based on a Fickian description of reactant diffusion; (ii) free‐volume theory based; (iii) chain‐length dependent; and, (iv) empirical. The reversible addition‐fragmentation technique is discussed, together with two industrially important case‐studies, solid state polycondensation and epoxy‐amine curing.magnified image
Acute vibration reduces Aβ nerve fiber sensitivity and alters gene expression in the ventral tail nerves of rats
Authors: Krajnak Kristine , Waugh Stacey , Wirth Oliver , Kashon Michael L. 
Published: May 2007

AbstractLong‐term occupational exposure to hand–arm vibration can result in a permanent reduction in tactile sensitivity in exposed fingers and hands. Little is known about how vibration causes this reduction in sensitivity, and currently no testing procedures have been developed to monitor changes in sensory perception during ongoing exposures. We used a rat‐tail model of hand–arm vibration syndrome (HAVS) to determine whether changes in sensory nerve function could be detected after acute exposure to vibration. Nerve function was assessed using the current perception threshold (CPT) method. We also determined whether changes in nerve function were associated with changes in gene transcription. Our results demonstrate that the CPT method can be used to assess sensory nerve function repeatedly in rats and can detect transient decreases in the sensitivity of Aβ nerve fibers caused by acute exposure to vibration. This decrease in Aβ fiber sensitivity was associated with a reduction in expression of nitric oxide synthase‐1, and a modest increase in calcitonin gene–related peptide transcript levels in tail nerves 24 h after vibration exposure. These transient changes in sensory perception and transcript levels induced by acute vibration exposure may be indicators of more prolonged changes in peripheral nerve physiology. Muscle Nerve, 2007
The Private sector in state service delivery: Examples of innovative practices
Authors: Hatry Harry P. , Skidmore Felicity 
Published: May 2007

AbstractTax‐limitation referenda and a presidential administration bullish on privatization have resulted in widespread use of the private sector to deliver state and local services. For years the stragglers of the privatization movement, states have more recently taken responsible and innovative steps toward involving the private sector in the areas of parks and recreation and human services.
Surface plasmon enhanced bright light emission from InGaN/GaN
Authors: Okamoto Koichi , Niki Isamu , Shvartser Alexander , Maltezos George , Narukawa Yukio , Mukai Takashi , Kawakami Yoichi , Scherer Axel 
Published: May 2007

AbstractSurface plasmon (SP) coupling technique was used to enhance blue and green light emissions from InGaN/GaN quantum wells (QWs). Large enhancement of photoluminescence (PL) of both blue and green emissions was observed with silver coated samples, whereas the enhancements were not so effective for the gold coated samples. We could obtain well enhanced green emission by tuning the matching condition of QW‐SP coupling with nano‐grating structures at gold layers. This method should be useful to design even more efficient structures and to fabricate super bright light emitting devices. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A hybrid model predictive control approach to the direct torque control problem of induction motors
Authors: Papafotiou Georgios , Geyer Tobias , Morari Manfred 
Published: May 2007

AbstractDirect torque control (DTC) is a state‐of‐the‐art control methodology for electric motor drives which features favourable control performance and implementation properties. In DTC, the core of the control system is the inverter switching table, and any efforts to enhance the system's performance aim at improving its design. This issue is addressed in this paper, where we propose a new design procedure for the DTC problem. The DTC drive, comprising a two‐ or three‐level dc‐link inverter driving a three‐phase induction motor, is modelled in the hybrid mixed logical dynamical (MLD) framework, and a constrained finite‐time optimal control problem is set up and solved over a receding horizon using model predictive control (MPC). Simulation results are provided and compared to the current industrial standard demonstrating the potential for notable performance improvements. Copyright © 2007 John Wiley & Sons, Ltd.
Non‐convex optimization and robustness in realtime model predictive control
Authors: DeHaan Darryl , Guay Martin 
Published: May 2007

AbstractRecent works in the nonlinear model predictive control (MPC) literature have presented ‘realtime’ optimization approaches based upon incremental updating of input parameters using local descent directions of the cost functional. The main downside to these methods is their strong dependence upon the values used to initialize the input parameters. In this note we study the robustness issues associated with non‐local search methods in continuous‐time MPC, and demonstrate a framework for robustly incorporating these approaches in a realtime setting. Copyright © 2007 John Wiley & Sons, Ltd.
A functional limit theorem for random graphs with applications to subgraph count statistics
Authors: Janson Svante 
Published: May 2007

AbstractWe consider a random graph that evolves in time by adding new edges at random times (different edges being added at independent and identically distributed times). A functional limit theorem is proved for a class of statistics of the random graph, considered as stochastic processes. the proof is based on a martingale convergence theorem. the evolving random graph allows us to study both the random graph model Kn, p, by fixing attention to a fixed time, and the model Kn, N, by studying it at the random time it contains exactly N edges. in particular, we obtain the asymptotic distribution as n → ∞ of the number of subgraphs isomorphic to a given graph G, both for Kn, p (p fixed) and Kn, N (N/(n2)→ p). the results are strikingly different; both models yield asymptotically normal distributions, but the variances grow as different powers of n (the variance grows slower for Kn, N; the powers of n usually differ by 1, but sometimes by 3). We also study the number of induced subgraphs of a given type and obtain similar, but more complicated, results. in some exceptional cases, the limit distribution is not normal.
Probabilistic analysis of a parallel algorithm for finding maximal independent sets
Authors: Calkin Neil , Frieze Alan 
Published: May 2007

AbstractWe consider a natural parallel version of the classical greedy algorithm for finding a maximal independent set in a graph. This version was studied in Coppersmith, Raghavan, and Tompa and they conjecture there that its expected running time on random graphs of arbitrary edge density of O (log n). We prove that conjecture.