bluuebunny/crossref_metadata_2025_split huggingface dataset:
Benjamin–Ono periodic bifurcating water waves in presence of an essential spectrum
Authors: Barrandon Matthieu 
Published: September 2006

The mathematical study of travelling waves in the potential flow of two superposed layers of perfect fluid can be set as an ill-posed evolutionary problem, in which the horizontal unbounded space variable plays the role of “time”. In this paper we consider two problems for which the bottom layer of fluid is infinitely deep: for the first problem, the upper layer is bounded by a rigid top and there is no surface tension at the interface; for the second problem, there is a free surface with a large enough surface tension. In both problems, the linearized operator

L_{ɛ}

(where

ɛ

is a combination of the physical parameters) around 0 possesses an
essential spectrum filling the entire real line
, with in addition a simple eigenvalue in 0. Moreover, for

ɛ < 0

, there is a pair of imaginary eigenvalues which meet in 0 when

ɛ = 0

and which disappear in the essential spectrum for

ɛ > 0

. For

ɛ > 0

small enough, we prove in this paper the existence of a two parameter family of periodic travelling waves (corresponding to periodic solutions of the dynamical system). These solutions are obtained in showing that the full system can be seen as a perturbation of the Benjamin–Ono equation. The periods of these solutions run on an interval

(T_{0},\infty )

possibly except a discrete set of isolated points.

Résumé

La recherche d'ondes progressives dans un système de deux couches superposées de fluides parfaits peut s'écrire comme un problème d'évolution mal posé, pour lequel la variable horizontale non bornée remplace le temps. Dans cet article, on étudie deux problèmes pour lesquels la couche inférieur de fluide est de profondeur infinie : dans le premier problème la couche supérieure est bornée par une surface rigide et il n'y a pas de tension de surface à l'interface ; pour le deuxième problème, la surface est libre mais avec une tension de surface élevée. Pour les deux problèmes, l'opérateur linéarisé à l'origine

L_{ɛ}

(où

ɛ

est une combinaison des paramètres physiques) possède, en plus d'une valeur propre simple en 0,
un spectre essentiel sur tout l'axe réel
. De plus, pour

ɛ < 0

, il y a une paire de valeurs propres imaginaires pures, qui se rencontrent à l'origine pour

ɛ = 0

, et qui disparaissent dans le spectre essentiel pour

ɛ > 0

. Pour

ɛ > 0

assez petit, on montre l'existence d'une famille à deux paramètres d'ondes progressives périodiques (qui correspondent à des solutions périodiques du système dynamique). Ces solutions sont obtenues en montrant que le système dynamique peut se réduire à une perturbation de l'équation de Benjamin–Ono. Les périodes de ces solutions appartiennent à un intervalle

(T_{0},\infty )

à l'exception possible d'un ensemble discret de points isolés.
Clustered solutions around harmonic centers to a coupled elliptic system
Authors: D'Aprile Teresa , Wei Juncheng 
Published: September 2006

We study the following system of Schrödinger–Maxwell equations

ɛ^{2}\mathrm{\Delta }v−v−\omega v\phi + f(v) = 0,\:\mathrm{\Delta }\phi + \gamma v^{2} = 0\:\text{in }\Omega ,

v,\phi > 0\:\text{in }\Omega ,\:v,\phi = 0\:\text{on}\:\partial \Omega ,

where

Ω

is a smooth and bounded domain of

\mathbb{R}^{3}

. We prove that for any integer

k

the system has a family of solutions

(v_{ɛ},\phi _{ɛ})

such that the form of

v_{ɛ}

consists of

k

spikes concentrating at a harmonic center of

Ω

as

ɛ\rightarrow 0^{ + }

. Furthermore we show that the spikes approach the vertexes of a configuration which maximizes a suitable geometrical problem.

Résumé
On étudie le système d'équations de Schrödinger–Maxwell suivant :

ɛ^{2}\mathrm{\Delta }v−v−\omega v\phi + f(v) = 0,\:\mathrm{\Delta }\phi + \gamma v^{2} = 0\:\text{dans }\Omega ,

v,\phi > 0\:\text{dans }\Omega ,\:v,\phi = 0\:\text{sur}\:\partial \Omega ,

où

Ω

est un ouvert borné régulier. On montre que pour tout entier

k

le système a une famille de solutions

(v_{ɛ},\phi _{ɛ})

telle que la forme de

v_{ɛ}

consiste en

k

pointes qui se concentrent sur un centre harmonique de

Ω

lorsque

ɛ\rightarrow 0^{ + }

. On montre, en plus, que les pointes approchent les sommets d'une configuration qui maximise un problème géométrique.
Regulatory genes controlling cell fate choice in embryonic and adult neural stem cells
Authors: Gangemi Rosaria Maria Rita , Perera Marzia , Corte Giorgio 
Published: September 2006

AbstractNeural stem cells are the most immature progenitor cells in the nervous system and are defined by their ability to self‐renew by symmetric division as well as to give rise to more mature progenitors of all neural lineages by asymmetric division (multipotentiality). The interest in neural stem cells has been growing in the past few years following the demonstration of their presence also in the adult nervous system of several mammals, including humans. This observation implies that the brain, once thought to be entirely post‐mitotic, must have at least a limited capacity for self‐renewal. This raises the possibility that the adult nervous system may still have the necessary plasticity to undergo repair of inborn defects and acquired injuries, if ways can be found to exploit the potential of neural stem cells (either endogenous or derived from other sources) to replace damaged or defective cells. A full understanding of the molecular mechanisms regulating generation and maintenance of neural stem cells, their choice between different differentiation programmes and their migration properties is essential if these cells are to be used for therapeutic applications. Here, we summarize what is currently known of the genes and the signalling pathways involved in these mechanisms.
Cholinergic modulation of microglial activation by α7 nicotinic receptors
Authors: Shytle R. Douglas , Mori Takashi , Townsend Kirk , Vendrame Martina , Sun Nan , Zeng Jin , Ehrhart Jared , Silver Archie A. , Sanberg Paul R. , Tan Jun 
Published: September 2006

AbstractAlmost all degenerative diseases of the CNS are associated with chronic inflammation. A central step in this process is the activation of brain mononuclear phagocyte cells, called microglia. While it is recognized that healthy neurons and astrocytes regulate the magnitude of microglia‐mediated innate immune responses and limit excessive CNS inflammation, the endogenous signals governing this process are not fully understood. In the peripheral nervous system, recent studies suggest that an endogenous ‘cholinergic anti‐inflammatory pathway’ regulates systemic inflammatory responses via α7 nicotinic acetylcholinergic receptors (nAChR) found on blood‐borne macrophages. These data led us to investigate whether a similar cholinergic pathway exists in the brain that could regulate microglial activation. Here we report for the first time that cultured microglial cells express α7 nAChR subunit as determined by RT–PCR, western blot, immunofluorescent, and immunochistochemistry analyses. Acetylcholine and nicotine pre‐treatment inhibit lipopolysaccharide (LPS)‐induced TNF‐α release in murine‐derived microglial cells, an effect attenuated by α7 selective nicotinic antagonist, α‐bungarotoxin. Furthermore, this inhibition appears to be mediated by a reduction in phosphorylation of p44/42 and p38 mitogen‐activated protein kinase (MAPK). Though preliminary, our findings suggest the existence of a brain cholinergic pathway that regulates microglial activation through α7 nicotinic receptors. Negative regulation of microglia activation may also represent additional mechanism underlying nicotine's reported neuroprotective properties.
TRP Channels: Molecular Diversity and Physiological Function
Authors: NISHIDA MOTOHIRO , HARA YUJI , YOSHIDA TAKASHI , INOUE RYUJI , MORI YASUO 
Published: September 2006

ABSTRACTCalcium ions (Ca2 +) are particularly important in cellular homeostasis and activity. To elicit physiologically relevant timing and spatial patterns of Ca2+ signaling, ion channels in the surface of each cell precisely control Ca2+ influx across the plasma membrane. A group of surface membrane ion channels called receptor‐activated cation/Ca2+ channels (RACCs) are activated by diverse cellular stimuli from the surrounding extracellular environment via receptors and other pathways such as heat, osmotic pressure, and mechanical and oxidative stress. An important clue to understanding the molecular mechanisms underlying the functional diversity of RACCs was first attained by molecular identification of the transient receptor potential (trp) protein (TRP), which mediates light‐induced depolarization in Drosophila photoreceptor cells, and its homologues from various biological species. Recent studies have revealed that respective TRP channels are indeed activated by characteristic cellular stimuli. Furthermore, the involvement of TRP channels has been demonstrated in the signaling pathways essential for tissue‐specific functions as well as ubiquitous biological responses, such as cell proliferation, differentiation, and death. These findings encourage the usage of TRP channels and their signalplexes as powerful tools for developing novel pharmaceutical targets.
Sensitization of Coronary α ‐Adrenoceptor Vasoconstriction in the Prediabetic Metabolic Syndrome
Authors: DINCER Ü. DENIZ , ARAIZA ALBERTO G. , KNUDSON JARROD D. , MOLINA PATRICIA E. , TUNE JOHNATHAN D. 
Published: September 2006

ABSTRACTObjective: This study tested whether α ‐adrenoceptor‐mediated coronary vasoconstriction is augmented in the metabolic syndrome and is accompanied by the alteration of specific α1‐ and α2‐coronary adrenoceptors.Methods: Studies were conducted in control and chronically high‐fat‐fed (6 weeks of 60% calories from fat) dogs with metabolic syndrome. Alterations in coronary α 1B‐, α1D‐, and α2A‐adrenoceptor mRNA and protein expression were examined by real‐time PCR and Western analyses, respectively. Coronary blood flow and its response to intracoronary infusion of either the α1‐adrenoceptor agonist methoxamine (0.1–3 mg) or the α2‐adrenoceptor agonist BHT‐933 (0.1–3 mg) were measured in anesthetized dogs.Results: Basal plasma epinephrine and norepinephrine levels were higher in the high‐fat‐fed dogs compared to controls. Real‐time PCR revealed no alterations of coronary artery or arteriole α1B‐, α1D‐, and α2A‐adrenoceptor mRNA expression. However, Western blot analysis showed a significant decrease in α2A‐adrenoceptor protein density with no change in α1B‐ or α 1D‐adrenoceptors. Methoxamine and BHT‐933 produced dose‐dependent decreases in coronary blood flow, but the decrease in coronary flow to methoxamine was significantly greater (∼ 20%) in dogs with the metabolic syndrome. No differences in the coronary flow response to BHT‐933 were noted.Conclusions: These results indicate that the metabolic syndrome is associated with sensitization of α1‐ and α2‐adrenoceptor signaling that could significantly limit control of coronary blood flow when the sympathetic nervous system is activated.
Lymph Flow, Shear Stress, and Lymphocyte Velocity in Rat Mesenteric Prenodal Lymphatics
Authors: DIXON J. BRANDON , GREINER STEVEN T. , GASHEV ANATOLIY A. , COTE GERARD L. , MOORE JAMES E. , ZAWIEJA DAVID C. 
Published: September 2006

ABSTRACTObjective: To measure lymphocyte velocity, lymphatic contraction, and shear stress in phasically contracting lymphatics in situ.Methods: A high‐speed video system was used to capture multiple contraction cycles in rat mesenteric lymphatic preparations. The images were analyzed to determine fluid velocity, volume flow rate, wall shear stress, and retrograde flow.Results: Lymphocyte density and flux varied from 326 to 35,500 cells/μ L and 206 to 2030 cells/min, respectively. Lymphatics contracted phasically, with a mean diameter 91 ± 9.0 μ m and amplitudes of 39%. Lymph velocity varied with the phasic contractions in both direction and magnitude with an average of 0.87 ± 0.18 and peaks of 2.2–9.0 mm/s. The velocity was ∼ 180° out of phase with the contraction cycle. The average lymph flow was 13.95 ± 5.27 μ L/h with transient periods of flow reversal. This resulted in an average shear of 0.64 ± 0.14 with peaks of 4–12 dynes/cm2.Conclusions: High‐speed lymphocyte tracking provided the spatial and temporal resolution to measure lymphocyte flux throughout the phasic contraction. Poiseuille flow was a reasonable model for estimating wall shear stress through most of the phasic contraction cycle of the intervalvular lymphatic segments. Shear rate was low but had large variations in magnitude compared to that seen in blood vessels.
Potential role of natural killer cells in controlling growth and infiltration of AIDS‐associated primary effusion lymphoma cells
Authors: Dewan Md. Zahidunnabi , Terunuma Hiroshi , Toi Masakazu , Tanaka Yuetsu , Katano Harutaka , Deng Xuewen , Abe Hiroyuki , Nakasone Tadashi , Mori Naoki , Sata Tetsutaro , Yamamoto Naoki 
Published: September 2006

Natural killer (NK) cells are an important component of the innate immune response against microbial infections and tumors. Direct involvement of NK cells in tumor growth and infiltration has not yet been demonstrated clearly. Primary effusion lymphoma (PEL) cells were able to produce tumors and ascites very efficiently with infiltration of cells in various organs of T‐, B‐ and NK‐cell knock‐out NOD/SCID/γcnull (NOG) mice within 3 weeks. In contrast, PEL cells formed small tumors at inoculated sites in T‐ and B‐cell knock‐out NOD/SCID mice with NK‐cells while completely failing to infiltrate into various organs. Immunosupression of NOD/SCID by treatment with an antimurine TM‐β1 antibody, which transiently abrogates NK cell activity in vivo, resulted in enhanced tumorigenicity and organ infiltration in comparison with non‐treated NOD/SCID mice. Activated human NK cells inhibited tumor growth and infiltration in NOG mice. Our results suggest that NK cells play an important role in growth and infiltration of PEL cells, and activated NK cells could be a promising immunotherapeutic tool against tumor or virus‐infected cells either alone or in combination with conventional therapy. The rapid and efficient engraftment of PEL cells in NOG mice also suggests that this new animal model could provide a unique opportunity to understand and investigate the mechanism of pathogenesis and malignant cell growth. (Cancer Sci 2006; 97: 1381–1387)
Characteristic expression of globotriaosyl ceramide in human ovarian carcinoma‐derived cells with anticancer drug resistance
Authors: Kiguchi Kazushige , Iwamori Yuriko , Suzuki Nao , Kobayashi Yoichi , Ishizuka Bunpei , Ishiwata Isamu , Kita Tsunekazu , Kikuchi Yoshihiro , Iwamori Masao 
Published: September 2006

The transporter protein genes and lipids in human ovarian carcinoma‐derived KF28 cells with anticancer‐drug‐sensitive properties were compared with those in resistant cells, taxol‐resistant KF28TX, cisplatin‐resistant KFr13, and taxol‐ and cisplatin‐resistant KFr13TX, to identify the molecules required for anticancer‐drug resistance. In accordance with previous reports, taxol and cisplatin resistance was closely correlated with expression of the multidrug resistance 1 and bile acid export pump, and multidrug resistance‐associated protein 2 genes, respectively. In addition, we found a distinct difference in glycosphingolipids between the sensitive and resistant cells. Although GlcCer was the major glycolipid (83.0%) in sensitive cells, GalCer, LacCer and, particularly, Gb3Cer were characteristically increased in all resistant cells, irrespective of whether the resistance was to taxol or cisplatin, and comprised 65–84% of total glycosphingolipids. GM3, which was present at 0.04 µg/mg dry weight in the sensitive cells, showed a twofold increase in the taxol‐resistant cells, but was absent in the cisplatin‐resistant cells. The altered glycolipid composition was proven to be due to enhanced or suppressed expression of the respective sugar transferase genes. In addition, the ceramide moiety of ceramide monohexoside in the sensitive cells constituted 83% of non‐hydroxy fatty acids, but that in the resistant cells comprised 67–74% of α‐hydroxy fatty acids. Thus, cells containing Gb3Cer with α‐hydroxy fatty acids were found to survive selectively in the presence of taxol and cisplatin, and modification of the glycolipid structure was revealed to occur in association with anticancer‐drug resistance. (Cancer Sci 2006; 97: 1321–1326)
Cessation of injection drug use and change in injection frequency: the Chicago Needle Exchange Evaluation Study
Authors: Huo Dezheng , Bailey Susan L. , Ouellet Lawrence J. 
Published: September 2006

ABSTRACTAims To examine the effect of a needle exchange program (NEP) on incidence of injection cessation and change in injection frequency; to explore predictors for injection cessation and change in injection frequency; and to assess whether injection quitters transitioned to non‐injected drug use.Design and setting Between 1997 and 2002, 901 injection drug users (IDUs) were recruited from an NEP program or an area with no NEP in Chicago, Illinois, interviewed for drug use behaviors, tested for HIV and followed for three annual visits. All participants were exposed to prevention services targeting HIV and drug abuse.Measurements Injection cessation was defined as no injection drug use since the last interview, and changes in the number of injections in a typical month were examined.Findings Sixteen per cent of study participants reported stopping injection for a median duration of 16 months, and most of them also ceased rather than initiated the use of non‐injected drugs. Those who continued injecting reduced their injection frequency by 12% per year, on average. Independent predictors of injection cessation were infrequent injection at baseline, younger age and injecting with others. NEP use was not associated with injection cessation and change in injection frequency.Conclusion These results did not support the hypothesis that NEP use influences the frequency of injection over time. One‐sixth of IDUs stopped injection for more than 1 year, providing a substantial window for relapse prevention interventions.
A randomized controlled trial to assess the effects of reimbursing the costs of smoking cessation therapy on sustained abstinence
Authors: Kaper J. , Wagena E. J. , Willemsen M. C. , Van Schayck C. P. 
Published: September 2006

ABSTRACTAims  We studied whether reimbursement for smoking cessation treatment (SCT) can increase prolonged abstinence from smoking up to 2 years.Setting, participants and design  From the general population, we recruited smokers and assigned them randomly to a control group (n = 634) or an intervention group (n = 632). For 6 months, participants in the intervention group could apply for reimbursement and received information regarding the reimbursed SCT. Participants in the control group received no reimbursement or information.Measurements  In this follow‐up study, prolonged abstinence from smoking was defined as reported being abstinent from at least 7 days before the end of reimbursement until the follow‐up assessment 6 months or 2 years later.Findings  At 6 months after the end of reimbursement, 18 participants in the control group (2.8%) and 35 participants (5.5%) in the intervention group reported sustained abstinence for at least 6 months [odds ratio (OR) = 2.0, 95% confidence interval (CI) 1.1–3.6]. Two years after the reimbursement period, 10 participants in the control group (1.6%) and 27 participants in the intervention group (4.3%) still reported sustained abstinence (OR = 4.1, 95% CI 1.7–10.2). The overall effectiveness of SCT increased with reimbursement and was 22% in the intervention group and 8% in the control group after 2 years.Conclusions  Reimbursement may be an effective strategy to increase the prolonged abstinence rate even after 2 years.
Contingency management for treatment of substance use disorders: a meta‐analysis
Authors: Prendergast Michael , Podus Deborah , Finney John , Greenwell Lisa , Roll John 
Published: September 2006

ABSTRACTAims  To examine the effectiveness of contingency management (CM) techniques in treating substance use disorders (i.e. illicit drugs, alcohol, tobacco).Design  Meta‐analysis was used to determine the average effect size and potential moderators in 47 comparisons of the effectiveness of CM from studies based on a treatment–control group design and published between 1970 and 2002.Findings  The mean effect size (ES) of CM was positive, with a magnitude of d = 0.42 using a fixed effects model. The magnitude of the ES declined over time, following treatment. CM was more effective in treating opiate use (d = 0.65) and cocaine use (d = 0.66), compared with tobacco (d = 0.31) or multiple drugs (d = 0.42). Larger effect sizes were associated with higher researcher involvement, earlier studies and shorter treatment duration.Conclusions  Study findings suggest that CM is among the more effective approaches to promoting abstinence during the treatment of substance use disorders. CM improves the ability of clients to remain abstinent, thereby allowing them to take fuller advantage of other clinical treatment components.
A detailed study of time‐dependent changes in human red blood cells: from reticulocyte maturation to erythrocyte senescence
Authors: Gifford Sean C. , Derganc Jure , Shevkoplyas Sergey S. , Yoshida Tatsuro , Bitensky Mark W. 
Published: September 2006

SummaryThe use of microfabrication technology in the study of biological systems continues to grow rapidly in both prevalence and ascendancy. Customised microdevices that provide superior results than traditional macroscopic methods can be designed in order to investigate specific cell types and cellular processes. This study showed the benefit of this approach in precisely characterising the progressive losses of surface area and haemoglobin (Hb) content by the human red blood cell (RBC), from newborn reticulocyte to senescent erythrocyte. The high‐throughput, multiparametric measurements made on individual cells with a specialised microdevice enabled, for the first time, delineation and quantification of the losses that occur during the two stages of the human RBC lifespan. Data acquired on tens of thousands of red cells showed that nearly as much membrane area is lost during the 1–2 d of reticulocyte maturation (c. 10–14%) as in the subsequent 4 months of erythrocyte ageing (c. 16–17%). The total decrease in Hb over the red cell lifespan is also estimated (c. 15%) and a model describing the complete time‐course of diminishing mean RBC area and Hb is proposed. The relationship between the losses of Hb and area, and their possible influence on red cell lifespan, are discussed.
Common gene expression signatures in t(8;21)‐ and inv(16)‐acute myeloid leukaemia
Authors: Ichikawa Hitoshi , Tanabe Kenji , Mizushima Hiroshi , Hayashi Yasuhide , Mizutani Shuki , Ishii Eiichi , Hongo Teruaki , Kikuchi Akira , Satake Masanobu 
Published: September 2006

SummaryHuman acute myeloid leukaemia (AML) involving a core‐binding factor (CBF) transcription factor is called CBF leukaemia. In these leukaemias, AML1 (RUNX1, PEBP2αB, CBFα2)‐MTG8 (ETO) and CBFβ (PEBP2β)‐MYH11 chimaeric proteins are generated by t(8;21) and inv(16) respectively. We analysed gene expression profiles of leukaemic cells by microarray, and selected genes whose expression appeared to be modulated in association with t(8;21) and inv(16). In a pair‐wise comparison, 15% of t(8;21)‐associated transcripts exhibited high or low expression in inv(16)‐AML, and 26% of inv(16)‐associated transcripts did so equivalently in t(8;21)‐AML. These common elements in gene expression profiles between t(8;21)‐ and inv(16)‐AML probably reflect the situation that AML1‐MTG8 and CBFβ‐MYH11 chimaeric proteins affect a common set of target genes in CBF leukaemic cells. On the other hand, 38% of t(8;21)‐associated and 24% of inv(16)‐associated transcripts were regulated in t(8;21)‐ and inv(16)‐specific manners. These distinct features of t(8;21)‐ and inv(16)‐associated genes correlate with the bimodular structures of the chimaeric proteins (CBF‐related AML1 and CBFβ portions, and CBF‐unrelated MTG8 and MYH11 portions).