bluuebunny/crossref_metadata_2025 huggingface dataset:
CFD simulation of dischargers' dilution‐zone in high consistency bleaching tower
Authors: Zeng J. S. , Chen K. F. , Chai X. S. , Li J.
Published: December 2010

In this work, the pulp flow behaviour for the dilution‐zone of two rotary dischargers, that is, S‐type and straight‐type discharger, were simulated by computational fluid dynamics (CFD). The time‐accurate transient simulations of two rotary dischargers were based on the standard k–ε turbulence model in conjunction with the granular Eulerian multiphase model and Sliding‐grid (SG) algorithm technique in FLUENT, so that the key parameters for evaluating the discharger performance, that is, the volume fraction of pulp, vectors of instantaneous water velocity, and turbulent kinetic energy of water in the given systems were calculated. The results from the simulations proved that the S‐type discharger was better than the straight one in pulp mixing and discharging. For the given S‐type discharger system, a higher revolution speed would lead to a smaller volume fraction thus makes pulp discharging much easier. The comparison results of the experiment data measured by particle image velocimetry (PIV) and CFD simulations verified that Eulerian and standard k–ε turbulence models could provide a better description for the flow patterns in the dilution‐zone.

Dans ce travail, le comportement de l'écoulement de pâtes pour la zone de dilution de deux déchargeurs rotatifs, c'est‐à‐dire un déchargeur de type S et un déchargeur droit, a été simulé par dynamique des fluides numérique (CFD). Les simulations transitoires à moments précis de deux déchargeurs rotatifs étaient basées sur le modèle standard de turbulence k–ε, en conjonction avec le modèle multiphase eulérien granulaire et la technique d'algorithme à grille coulissante dans FLUENT, de telle façon que les paramètres clés pour l'évaluation du rendement des déchargeurs, c'est‐à‐dire la fraction de volume de pâte, les vecteurs de vélocité instantanée de l'eau et l'énergie cinétique turbulente de l'eau dans les systèmes considérés ont pu être calculés. Les résultats des simulations ont prouvé que le déchargeur de type S était meilleur que le déchargeur droit pour le mélange et le déchargement des pâtes. Pour le déchargeur de type S donné, une vitesse de rotation supérieure entraînait une fraction de volume inférieure, ce qui rend la décharge des pates bien plus facile. Les résultats de comparaison des données d'expérience mesurées par vélocimétrie d'images multiples de particules (VIPV) et simulations CFD simulations permettaient de vérifier que le modèle eulérien et le modèle standard de turbulence k–ε pouvaient donner une meilleure description des modèles d'écoulement dans la zone de dilution. © 2010 Canadian Society for Chemical Engineering
Degradation of Reactive Brilliant Red X‐3B Dye by Microwave Electrodeless UV Irradiation
Authors: Cai Ying‐Jie , Lin Li‐Na , Xia Dong‐Sheng , Zeng Qing‐Fu , Zhu Hai‐Liang
Published: December 2010

Degradations of reactive brilliant red X‐3B solution by both conventional UV irradiation and microwave electrodeless UV irradiation were investigated. Degradation processes were studied by UV–VIS spectrophotometry, total organic carbon (TOC), high performance capillary electrophoresis (HPCE), conductivity, pH value, and ion chromatography. The results of color removal (%) and TOC removal (%) showed that the degradation by microwave electrodeless UV irradiation was more effective than by conventional UV irradiation. The results of UV–VIS absorption spectra and HPCE analyses indicated that the degradation of reactive brilliant red X‐3B was occurred at the conjugation system first, the benzene ring and the naphthalene ring later. The reactive brilliant red X‐3B was cleaved into some new small compounds and eventually most of the organic substances were mineralized to CO2 and H2O. The results of the conductivity analysis suggested that the degradation has mainly occurred in the first 40 min of reaction. The pH value of reactive brilliant red X‐3B solution was decreased first and then was increased. The results of inorganic anions analysis hinted that many of the N, Cl, and S elements from reactive brilliant red X‐3B were still attached in organic molecules.
Design, Synthesis and Biological Evaluation of Novel Inhibitors of Trypanosoma brucei Pteridine Reductase 1
Authors: Spinks Daniel , Ong Han B. , Mpamhanga Chidochangu P. , Shanks Emma J. , Robinson David A. , Collie Iain T. , Read Kevin D. , Frearson Julie A. , Wyatt Paul G. , Brenk Ruth , Fairlamb Alan H. , Gilbert Ian H.
Published: December 2010

Genetic studies indicate that the enzyme pteridine reductase 1 (PTR1) is essential for the survival of the protozoan parasite Trypanosoma brucei. Herein, we describe the development and optimisation of a novel series of PTR1 inhibitors, based on benzo[d]imidazol‐2‐amine derivatives. Data are reported on 33 compounds. This series was initially discovered by a virtual screening campaign (J. Med. Chem., 2009, 52, 4454). The inhibitors adopted an alternative binding mode to those of the natural ligands, biopterin and dihydrobiopterin, and classical inhibitors, such as methotrexate. Using both rational medicinal chemistry and structure‐based approaches, we were able to derive compounds with potent activity against T. brucei PTR1 (${K{{{\rm app}\hfill \atop {\rm i}\hfill}}}$=7 nM), which had high selectivity over both human and T. brucei dihydrofolate reductase. Unfortunately, these compounds displayed weak activity against the parasites. Kinetic studies and analysis indicate that the main reason for the lack of cell potency is due to the compounds having insufficient potency against the enzyme, which can be seen from the low Km to Ki ratio (Km=25 nM and Ki=2.3 nM, respectively).
Synthesis and characterization of new low‐molecular‐weight lysine‐conjugated Gd‐DTPA contrast agents
Authors: Laurent Sophie , Burtea Carmen , Vander Elst Luce , Muller Robert N.
Published: December 2010

Various blood pool contrast agents (CAs), characterized by intravascular distribution, have been developed to assist contrast enhanced magnetic resonance angiography (MRA). Among these CAs, the DTPA derivatives conjugated to synthetic polypeptides, such as polylysine, represent attractive candidates for blood pool imaging. However, due to the presence of charged residues located on their backbone, these agents are retained in the kidneys and this compromises their long blood half‐life. In order to overcome this major drawback of the polylysine compounds, two new low‐molecular‐weight CAs were synthesized in the present work by conjugating four or six 1‐p‐isothiocyanatobenzyl‐DTPA moieties to tri‐ or penta‐Lys peptides [(Gd‐DTPA)4Lys3 and (Gd‐DTPA)6Lys5], respectively. All the –NH2 groups of Lys were thus blocked by covalent conjugation to DTPA. The stability and relaxometric properties of these compounds, as well as their pharmacokinetic and biodistribution characteristics, were then evaluated. The half‐life in blood of these new polylysine derivatives, as determined in rats, is twofold longer than that of Gd‐DTPA. The compounds could thus be optimal blood pool markers for MRA, which typically uses fast acquisition times. The absence of positive molecular charge did not limit their retention in kidneys 2 h after administration. On the other hand, (Gd‐DTPA)4Lys3 is retained in kidneys to a lesser extent than (Gd‐DTPA)6Lys5. Their moderate retention in blood and their higher stability and relaxivity in comparison with Gd‐DTPA highlight these polylysine derivatives as optimal compared with previously developed polylysine compounds. Copyright © 2010 John Wiley & Sons, Ltd.
A fluorescent chromophore TOTO‐3 as a ‘smart probe’ for the assessment of ultrasound‐mediated local drug delivery in vivo
Authors: Deckers Roel , Yudina Anna , Cardoit Laura C. , Moonen Chrit T. W.
Published: December 2010

Many potent anti‐cancer drugs have an intracellular mode of action, but are limited in crossing the cell membrane, resulting in a reduced clinical efficacy. Ultrasound (US) is known to facilitate the penetration of drugs into tumors cells. However (molecular) imaging techniques that monitor in vivo the underlying processes of US‐triggered drug delivery are lacking. The objective of this study was to demonstrate the feasibility of using a fluorescent nuclear acid stain (TOTO‐3) as a model drug to monitor in real‐time US‐mediated delivery by in vivo fluorescence imaging. Following co‐injection of TOTO‐3 and microbubbles US was applied to the tumor. The time course of the drug delivery process was monitored by fluorescence imaging. Immunohistological analysis and in vitro experiments were performed to investigate the results in more detail. A significant signal intensity enhancement of the US‐treated tumor was observed that indicates intracellular delivery of the dye. In the control tumor TOTO‐3 signal was strongly associated with macrophages, which was not the case for the sonicated tumor. The capability of macrophages to uptake TOTO‐3 was confirmed in vitro. This study demonstrates that an optical contrast agent with similar characteristics to an anti‐cancer drug may be used for continuous in vivo monitoring of the drug delivery process. Copyright © 2010 John Wiley & Sons, Ltd.
Soft tissue sarcomas of the popliteal fossa
Authors: Huh Winston W. , Guadagnolo B. Ashleigh , Munsell Mark F. , Patel Shreyaskumar , Lewis Valerae O.
Published: December 2010

BACKGROUND:

Soft tissue sarcomas (STSs) arising from the popliteal fossa present a challenge with regard to local control of primary tumors. Due to concerns of functional morbidity and neurovascular compromise, there is debate about what represents the best therapy for these patients.

METHODS:

We conducted a retrospective medical record review of patients treated at The University of Texas M. D. Anderson Cancer Center for STS of the popliteal fossa from 1990 to 2008.

RESULTS:

There were 47 eligible patients, 28 of whom were male and 19 of whom were female. Synovial sarcoma was the most common diagnosis, with 12 cases. Most patients had T2b tumors (31 patients; 66%). The median duration of follow‐up was 3.8 years (range, 0.6‐17.9 years). The 5‐ and 10‐year overall survival rates were 63% and 51%, respectively. Metastasis at diagnosis was associated with poorer overall survival (5‐year overall survival, 74% versus 13%; P<.001) and poorer recurrence‐free survival (5‐year recurrence‐free survival, 51% versus 0%; P<.001) on univariate analysis. Radiation therapy improved local recurrence‐free survival (5‐year local recurrence‐free survival, 56% versus 17%; P = .004), whereas a trend was observed for surgical margin status (P = .07). Tumor size and neurovascular involvement did not influence outcome. Twenty‐two patients had recurrent disease, with 15 patients having local recurrence, and 16 patients died from progressive disease.

CONCLUSIONS:

Radiation therapy may play an important role in the treatment of popliteal fossa STS, but further study is needed to better define the best clinical application. Additional study is needed to re‐evaluate association of surgical margin status and outcome. Cancer 2011; © 2010 American Cancer Society.
Translocation t(14;18)/IGH‐BCL2 in gastrointestinal follicular lymphoma
Authors: Yanai Shunichi , Nakamura Shotaro , Takeshita Morishige , Fujita Kouhei , Hirahashi Minako , Kawasaki Keisuke , Kurahara Koichi , Sakai Yuji , Matsumoto Takayuki
Published: December 2010

BACKGROUND:

Chromosomal translocation t(14;18)(q32;q21) involving the immunoglobulin heavy chain gene (IGH) and the BCL2 gene (t[14;18][q32;q21]/IGH‐BCL2) is present in 60% to 90% of nodal follicular lymphomas. To the authors' knowledge, the prevalence and clinical significance of this translocation have not been examined previously in gastrointestinal follicular lymphomas.

METHODS:

Clinicopathologic and molecular features were investigated in 48 patients who had gastrointestinal follicular lymphoma. The site of involvement was the duodenum in 54% of patients, the jejunum in 52%, the ileum in 52%, the stomach in 29%, and the colorectum in 15%. The presence of the t(14;18)/IGH‐BCL2 translocation was detected by interphase fluorescence in situ hybridization.

RESULTS:

Treatment modalities included surgical resection (n = 16), rituximab plus chemotherapy (n = 13), rituximab alone (n = 6), antibiotics (n = 5), and watchful waiting (n = 8). Complete remission (CR) of lymphoma was achieved in 31 patients (65%). The overall survival and event‐free survival rates after 5 years were 93% and 68%, respectively. The t(14;18)/IGH‐BCL2 was detected in 39 patients (81%). The involvement of multiple sites (69% vs 0%), manifestation of the lymphomatous polyposis type (72% vs 22%), and histologic grade 1 or 2 tumors (92% vs 56%) were more frequent in the t(14;18)‐positive group than in the negative group. In addition, the CR rate was lower in the t(14;18)‐positive group than in the negative group (56% vs 100%; P = .0179), and a trend was observed toward poorer event‐free survival in the positive group (P = .089).

CONCLUSIONS:

The t(14;18)/IGH‐BCL2 chromosomal translocation occurred frequently in gastrointestinal follicular lymphomas. The current results indicated that this translocation may be a predictor of an adverse clinical course. Cancer 2011. © 2010 American Cancer Society.
Association of the highly prevalent TP53 R337H mutation with pediatric choroid plexus carcinoma and osteosarcoma in Southeast Brazil
Authors: Seidinger Ana Luiza , Mastellaro Maria José , Paschoal Fortes Fernanda , Godoy Assumpção Juliana , Aparecida Cardinalli Izilda , Aparecida Ganazza Mônica , Correa Ribeiro Raul , Brandalise Silvia Regina , dos Santos Aguiar Simone , Yunes José Andrés
Published: December 2010

BACKGROUND:

The inherited, low‐penetrance arginine‐to‐histidine substitution at codon 337 (R337H) of the tumor protein 53 gene (TP53) is clustered in southeast Brazil (estimated frequency, 0.3%). Although its tumorigenic effect initially appeared to be tissue‐specific, recent evidence suggests its association with a broader range of tumors. Therefore, the authors of this report investigated the spectrum of pediatric malignancies associated with the TP53 R337H mutation at a single referral institution in southeast Brazil.

METHODS:

Genomic DNA samples from 493 children with malignancies were screened for the R337H mutation. Available tumor samples from carriers were investigated for loss of heterozygosity (LOH) and nuclear p53 accumulation. Clinical data were obtained from medical records.

RESULTS:

Sixty‐five of 70 patients (93%) with adrenocortical tumors (ACTs), 9 of 13 patients (69%) with choroid plexus carcinoma (CPC), and 3 of 41 patients (7.3%) with osteosarcoma carried the mutation. The proportion of CPC to choroid plexus papilloma (CPP) was much higher than that reported elsewhere. Osteosarcoma in carriers had a significantly poorer outcome (P = .02). The mutation was not identified in patients who had acute lymphoblastic leukemia (ALL) (n = 187), recurrent ALL (n = 49), acute myeloid leukemia (n = 44), lymphoma (n = 30), non‐CPC central nervous system tumors (n = 26), Ewing sarcoma (n = 25), or rhabdomyosarcoma (n = 8). Among the tumors that were available for analysis, LOH with retention of the mutant allele was confirmed in 21 of 21 ACTs, in 2 of 2 CPCs, and in 2 of 3 osteosarcomas that were positive for R337H. CPCs and osteosarcomas that were positive for R337H had marked nuclear accumulation of p53.

CONCLUSIONS:

The current findings demonstrated compellingly that the TP53 R337H mutation is associated not only with ACT but also with CPC and, to a lesser extent, with osteosarcoma, both of which are core‐component tumors of the Li‐Fraumeni syndrome. Cancer 2011. © 2010 American Cancer Society.
Interconnected cortical networks between primary somatosensory cortex septal columns and posterior parietal cortex in rat
Authors: Lee Taehee , Alloway Kevin D. , Kim Uhnoh
Published: December 2010

Visual and somesthetic cues are used for spatial processing in the posterior parietal cortex (PPC) of the mammalian brain. In rats, somatic information collected by the mystacial whiskers is critically involved in constructing a neural representation of the external space. Here, we delineated the topography of the cortical pathway from primary somatosensory cortex (SI) that may deliver vibrissal cues to PPC for spatial processing. For anterograde tracing, we made small injections of biotinylated dextran amine (BDA) into SI barrel cortex. The injections in the regions directly above the septal compartments produced dense terminals in PPC, whereas injections above the center of the barrels resulted in sparse terminals. For retrograde tracing, we made large injections of cholera toxin subunit B (CtB) in PPC. Retrogradely labeled neurons within SI barrel cortex formed multiple, parallel strips. In layer IV, these strips of labeled neurons were confined within the septal rows, extending from barrel arc position 0 to 5. In the extragranular layers, labeled neurons were clustered primarily within the vertical extensions of the septal rows and extended to the edges of neighboring barrel columns. Based on these findings, in which SI projections to PPC arise mainly from the septal columns, we hypothesize that septal columns may form interconnected cortical networks that engage in spatial information processing contingent on somestheic cues. J. Comp. Neurol. 519:405–419, 2011. © 2011 Wiley‐Liss, Inc.
Molecular Adsorbates at Single‐Crystal Platinum‐Group Metals and Bimetallic Surfaces
Authors: Baltruschat Helmut , Ernst Siegfried
Published: December 2010

The surface orientation of Pt‐group metals determines the kind of organic species (such as CO, benzene and ethene) that will adsorb on them as well as the prevailing reaction channels. Pt and Pd as well as (sub)monolayers of them on Au are compared, including mono‐ and multiatomic rows of Pd on stepped Au surfaces. In general, Pd is less active for oxidation or hydrogenation of the adsorbates. Desorption of the intact molecule is favored because of a lower adsorption strength.
FRET Microscopy in 2010: The Legacy of Theodor Förster on the 100th Anniversary of his Birth
Authors: Sun Yuansheng , Wallrabe Horst , Seo Soo‐Ah , Periasamy Ammasi
Published: December 2010

Theodor Förster would have been 100 years old this year, and he would have been astounded to see the impact of his scientific achievement, which is still evolving. Combining his quantitative approach of (Förster) resonance energy transfer (FRET) with state‐of‐the‐art digital imaging techniques allows scientists to breach the resolution limits of light (ca. 200 nm) in light microscopy. The ability to deduce molecular or particle distances within a range of 1–10 nm in real time and to prove or disprove interactions between two or more components is of vital interest to researchers in many branches of science. While Förster’s groundbreaking theory was published in the 1940s, the availability of suitable fluorophores, instruments, and analytical tools spawned numerous experiments in the last 20 years, as demonstrated by the exponential increase in publications. These cover basic investigation of cellular processes and the ability to investigate them when they go awry in pathological states, the dynamics involved in genetics, and following events in environmental sciences and methods in drug screening. This review covers the essentials of Theodor Förster’s theory, describes the elements for successful implementation of FRET microscopy, the challenges and how to overcome them, and a leading‐edge example of how Förster’s scientific impact is still evolving in many directions. While this review cannot possibly do justice to the burgeoning field of FRET microscopy, a few interesting applications such as three‐color FRET, which greatly expands the opportunities for investigating interactions of cellular components compared with the traditional two‐color method, are described, and an extensive list of references is provided for the interested reader to access.
Control of Cross Relaxation of Multiple‐Quantum Coherences Induced by Fast Chemical Exchange under Heteronuclear Double‐Resonance Irradiation
Authors: Ulzega Simone , Salvi Nicola , Segawa Takuya F. , Ferrage Fabien , Bodenhausen Geoffrey
Published: December 2010

A fully analytical description of the control of the cross‐correlated cross relaxation of multiple‐quantum coherences in the presence of local dynamics under heteronuclear double‐resonance radio‐frequency (RF) irradiation is presented. The contribution of chemical exchange to relaxation can be partly or fully quenched by RF fields. We assume a correlated two‐site chemical exchange model with arbitrary populations, and show that in the limit of fast exchange the dependence of the effective multiple‐quantum cross‐relaxation rate on the applied RF amplitude can be described by a compact analytical expression. Numerical simulations and preliminary experiments support our theoretical results. The relaxation dispersion as a function of RF amplitude can provide accurate information on the kinetics of correlated processes.
Chirality Measures for Vectors, Matrices, Operators and Functions
Authors: Dryzun Chaim , Avnir David
Published: December 2010

We introduce the general form of the continuous chirality measure (CCM), which is a quantitative estimation of the degree of chirality for a given object. The generalization makes it possible to calculate the chirality content of any mathematical description of a system by vectors, matrices, operators and functions. Another advantage of the new methodology is the ability to provide analytical expressions for the chirality measures. We apply it for specific cases, including vectors and molecules (amino acids), rotation matrices (metamaterials design), rotational potential operators (representing, for example, parity violation), and functions (the electronic structure of annulenes).
Thermomorphic Behavior of the Ionic Liquids [C4mim][FeCl4] and [C12mim][FeCl4]
Authors: Xie Zai‐Lai , Taubert Andreas
Published: December 2010

The iron‐containing ionic liquids 1‐butyl‐3‐methylimidazolium tetrachloroferrate(III) [C4mim][FeCl4] and 1‐dodecyl‐3‐methylimidazolium tetrachloroferrate(III) [C12mim][FeCl4] exhibit a thermally induced demixing with water (thermomorphism). The phase separation temperature varies with IL weight fraction in water and can be tuned between 100 °C and room temperature. The reversible lower critical solution temperature (LCST) is only observed at IL weight fractions below ca. 35 % in water. UV/Vis, IR, and Raman spectroscopy along with elemental analysis prove that the yellow‐brown liquid phase recovered after phase separation is the starting IL [C4mim][FeCl4] and [C12mim][FeCl4], respectively. Photometry and ICP‐OES show that about 40 % of iron remains in the water phase upon phase separation. Although the process is thus not very efficient at the moment, the current approach is the first example of an LCST behavior of a metal‐containing IL and therefore, although still inefficient, a prototype for catalyst removal or metal extraction.
HomoFRET Fluorescence Anisotropy Imaging as a Tool to Study Molecular Self‐Assembly in Live Cells
Authors: Chan Fiona T. S. , Kaminski Clemens F. , Kaminski Schierle Gabriele S.
Published: December 2010

Molecular self‐assembly is a defining feature of numerous biological functions and dysfunctions, ranging from basic cell signalling to diseases mediated by protein aggregation. There is current demand for novel experimental methods to study molecular self‐assembly in live cells, and thereby in its physiological context. Förster resonance energy transfer (FRET) between fluorophores of a single type, known as homoFRET, permits noninvasive detection and quantification of molecular clusters in live cells. It can thus provide powerful insights into the molecular physiology of living systems and disease. HomoFRET is detected by measuring the loss of fluorescence anisotropy upon excitation with polarised light. This article reviews recent key developments in homoFRET fluorescence anisotropy imaging for the detection and quantification of molecular self‐assembly reactions in biological systems. A summary is given of the current state‐of‐the‐art and case studies are presented of successful implementations, highlighting technical aspects which have to be mastered to bridge the gap between proof‐of‐concept experiments and biological discoveries.
Observation of Runaway Electron Behaviour During Disruptions in LHCD Discharges in the HT‐7 Tokamak
Authors: Lu H. W. , Hu L. Q. , Li S. Y. , Zhou R. J. , Zhong G. Q. , the HT‐7 Team
Published: December 2010

Production of runaway electrons during disruptions has been observed in the HT‐7 Tokamak. The runaway current plateaus, which can carry part of the pre‐disruptive current, are observed in lower‐hybrid current drive (LHCD) limiter discharges. It is found that the runaway current can mitigate the disruptions effectively. We can use gas puffing to increase the line‐averaged density to restrain the runaway electrons and rebuild the plasmas after the disruptions. Detailed observations are presented on the runaway electrons generated following disruptions in the HT‐7 tokamak discharges. The results indicate that the magnetic oscillations play a significant role in the loss of runaway electrons in disruptions. There are two important preconditions to rebuild plasmas by runaway electrons after the disruptions. One of them are weak magnetic oscillations; another one are LHWs (lower‐hybrid waves) (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nonlinear Behavior of Electromagnetic Waves in Ultra‐Relativistic Electron‐Positron Plasmas
Authors: Liu Y. , Liu S. Q.
Published: December 2010

A set of nonlinear equations which can self‐consistently describe the behavior of high frequency Electromagnetic (EM) waves in un‐magnetized, ultra‐relativistic electron‐positron (e‐p) plasmas is obtained on the basis of Vlasov‐Maxwell equations. Nonlinear wave‐wave, wave‐particle interactions lead to the coupling of high frequency EM waves with low frequency density perturbations which result from EM waves radiation pressure. The same as that in conventional electron‐ion (e‐i) plasmas, strong EM waves in e‐p plasmas will give rise to density depletion in which itself are trapped. But on the contrary to that in e‐i plasmas, there no longer exists electrostatic acoustic–like wave in e‐p plasmas due to the absence of mass difference. For linear polarized EM waves, a stationary EM soliton with a spiky structure will be formed. The possible relation of the localized field to pulsar radio pulse is discussed (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The Effect of a Poloidal Phase Difference on the Asymmetry of the Coupling Characteristics of an ICRH Antenna
Authors: Du Dan , Gong Xue‐Yu , Hu He‐Ping , Liu Bai‐Qing , Huang Qian‐Hong , Lu Xing‐Qiang
Published: December 2010

The coupling asymmetry characteristics of an ion cyclotron resonance heating (ICRH) antenna consisting of two poloidal aligned straps are studied for a JET‐type tokamak. The model used combines a three‐dimensional (3‐D) planar, cold‐plasma, single pass antenna‐plasma coupling code with any phase difference between the current straps, which takes into account the feeders' current and phase difference effects. The result shows that the asymmetry of radiated energy in poloidal direction can be controlled through changing the phase difference of the antenna straps, and when the phase difference equals to π, the asymmetry tends to become most pronounced (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effective Polytropic Indices of Anisotropic Planetary Magnetosheath Plasmas with Magnetoacoustic Waves
Authors: Meister C.‐V. , Maurer Ch. , Hoffmann D.H.H.
Published: December 2010

Magnetosheath models for the planets Earth, Jupiter and Saturn are developed within the frame of the double‐adiabatic Chew‐Goldberger‐Low approximation. It is shown that in all three magnetosheaths slow and fast magnetoacoustic waves are generated, the dispersions of which considerably differ from that of isotropic systems. If slow magnetoacoustic waves exist in the magnetosheaths, then the effective polytropic coefficient of the plasma may be smaller than unity ‐ that means compression of the plasma is accompanied, in the average, by cooling. Such polytropic coefficients are not obtained when fast magnetoacoustic waves are excited (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Local Field Corrections Effect on Equation of State in Dense Hydrogen Plasma: Plasma Phase Transition
Authors: Bennadji K.
Published: December 2010

We present calculations of Hydrogen plasma pressure including local field correction (LFC) effects modelled in the Singwi Tosi Land and Sjölander model extended to arbitrary temperature (ATSTLS), neutrals contributions are not included. We show that LFC induces thermodynamic instabilities (phase transition) in the vicinity of the maximum electron coupling parameter which corresponds to maximum departure of the ATSTLS electron polarizability from the Random Phase Approximation one. Comparison of our results to Monte‐Carlo calculations induced us to think that free electron coupling plays a dominant role in plasma phase transition. Critical temperature is estimated and compared to existing values (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electron Temperature Dependence of the Dissociative Recombination Coefficient of Molecular Argon Ions Ar+2 with Electrons
Authors: Lukáč P. , Mikuš O. , Morva I. , Zábudlá Z. , Trnovec J. , Morvová M.
Published: December 2010

A dual mode (TM010 cylindrical cavity/cylindrical waveguide) microwave apparatus is used to study the ion mobility and dissociative recombination of molecular argon ions with electrons in the afterglow period of a d.c. glow discharge as a function of electron temperature when electrons were heated by microwaves up to Te ≤ 10300K, with T+ = Tgas = 300K. The electron temperature dependence of the total rate coefficient of dissociative recombination may be represented by α (Ar+2) = (8.1 ± 0.5) × 10–7[300/Te(inK)]0.64cm3s–1 which is in very good agreement with most previous experimental results but not with the recent theoretical calculations (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The Quantum Excess Free Energy for Two Component Plasma
Authors: Hussein N. A. , Ibrahim D. A. E.
Published: December 2010

The aim of this paper is to calculate the quantum excess free energy until the third virial coefficient for the two component plasma (TCP). We consider only the thermal equilibrium plasma in the case of nλ3ab ≪ 1 where λ2ab = (ħ2/(mabKT)) is the thermal De Broglie wave‐length. The second and third virial coefficients are represented in forms of a convergent series expansion in terms of the interaction Parameter ξ2ab = ((eaeb)/(λabKT)). We obtained the excess free energy until the third virial coefficient to the order ξ6ab. The effects of symmetry are taken into account, also the exchange effects were taken in account. We compared our results with others. Upon comparison with Ebeling et al. one observes that the considerable contribution of the third virial coefficient in the region of high temperatures (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Environmental enrichment influences neuronal stem cells in the adult crayfish brain
Authors: Ayub Neishay , Benton Jeanne L. , Zhang Yi , Beltz Barbara S.
Published: December 2010

New neurons are incorporated throughout life into the brains of many vertebrate and nonvertebrate species. This process of adult neurogenesis is regulated by a variety of external and endogenous factors, including environmental enrichment, which increases the production of neurons in juvenile mice and crayfish. The primary goal of this study was to exploit the spatial separation of the neuronal precursor cell lineage in crayfish to determine which generation(s) of precursors is altered by environmental conditions. Further, in crayfish, an intimate relationship between the first‐generation neuronal precursors (stem cells) and cells circulating in the hemolymph has been proposed (Zhang et al., 2009). Therefore, a second goal was to assess whether environmental enrichment alters the numbers or types of cells circulating in the hemolymph. We find that neurogenesis in the brains of sexually differentiated procambarid crayfish is enhanced by environmental enrichment as previously demonstrated by Sandeman and Sandeman (2000) in young, sexually undifferentiated Cherax destructor. We also show that environmental enrichment increases the cell cycle rate of neuronal stem cells. Although there was no effect of environment on the overall numbers of cells circulating in the hemolymph, enrichment resulted in increased expression of glutamine synthetase (GS), a marker of the neuronal stem cells, in a small percentage of circulating cells; there was little or no GS immunoreactivity in hemolymph cells extracted from deprived animals. Thus, environmental enrichment influences the rate of neuronal stem cell division in adult crayfish, as well as the composition of cells circulating in the hemolymph. © 2010 Wiley Periodicals, Inc. Develop Neurobiol 71: 351–361, 2011
Neurongrowth, a software for automatic quantification of neurite and filopodial dynamics from time‐lapse sequences of digital images
Authors: Fanti Zian , Elena Martinez‐Perez M. , De‐Miguel Francisco F.
Published: December 2010

We developed NeuronGrowth, a software for the automatic quantification of extension and retraction of neurites and filopodia, from time‐lapse sequences of two‐dimensional digital micrographs. NeuronGrowth requires a semiautomatic characterization of individual neurites in a reference frame, which is then used for automatic tracking and measurement of every neurite over the whole image sequence. Modules for sequence alignment, background subtraction, flat field correction, light normalization, and cropping have been integrated to improve the quality of the analysis. Moreover, NeuronGrowth incorporates a deconvolution filter that corrects the shadow‐cast effect of differential interference contrast (DIC) images. NeuronGrowth was tested by analyzing the formation of outgrowth patterns by individual leech neurons cultured under two different conditions. Phase contrast images were obtained from neurons plated on CNS homogenates and DIC images were obtained from similar neurons plated on ganglion capsules as substrates. Filopodia were measured from fluorescent growth‐cones of chick dorsal root ganglion cells. Quantitative data of neurite extension and retraction obtained by three different users applying NeuronGrowth and two other manually operated software packages were similar. However, NeuronGrowth required less user participation and had a better time performance when compared with the other software packages. NeuronGrowth may be used in general to quantify the dynamics of tubular structures such as blood vessels. NeuronGrowth is a free plug‐in for the free software ImageJ and can be downloaded along with a user manual, a troubleshooting section and other information required for its use from http://www.ifc.unam.mx or http://www.ifc.unam.mx/ffm/index.html. © 2010 Wiley Periodicals, Inc. Develop Neurobiol 71: 870–881, 2011
Par proteins and neuronal polarity
Authors: Insolera Ryan , Chen She , Shi Song‐Hai
Published: December 2010

A hallmark of neurons is their ability to polarize with dendrite and axon specification to allow the proper flow of information through the nervous system. Over the past decade, extensive research has been performed in an attempt to understand the molecular and cellular machinery mediating this neuronal polarization process. It has become evident that many of the critical regulators involved in establishing neuronal polarity are evolutionarily conserved proteins that had previously been implicated in controlling the polarization of other cell types. At the forefront of this research are the partition defective (Par) proteins. In this review,we will provide a commentary on the progressof work regarding the central importance of Parproteins in the establishment of neuronal polarity. © 2010 Wiley Periodicals, Inc. Develop Neurobiol 71: 483–494, 2011
Enteric neurons synthesize netrins and are essential for the development of the vagal sensory innervation of the fetal gut
Authors: Ratcliffe Elyanne M. , Fan Lena , Mohammed Tandi J. , Anderson Monique , Chalazonitis Alcmène , Gershon Michael D.
Published: December 2010

During fetal life, vagal sensory fibers establish a reproducible distribution in the gut that includes an association with myenteric ganglia. Previous work has shown that netrin is expressed in the bowel wall and, by acting on its receptor, deleted in colorectal cancer (DCC), mediates the guidance of vagal sensory axons to the developing gut. Because the highest concentration of netrins in fetal bowel is in the endoderm, we tested the hypothesis that the ingrowth of vagal afferents to the gut would be independent of the presence of enteric neurons, although enteric neurons might influence the internal distribution of these fibers. Surprisingly, experiments indicated that the vagal sensory innervation is intrinsic neuron‐dependent. To examine the vagal innervation in the absence of enteric ganglia, fetal Ret −/− mice were labeled by applying DiI bilaterally to nodose ganglia. In Ret −/− mice, DiI‐labeled vagal sensory axons descended in paraesophageal trunks as far as the proximal stomach, which contains neurons, but did not enter the aganglionic bowel. To determine whether neurons produce netrins, enteric neural‐crest‐derived cells (ENCDCs) were immunoselected from E15 rat gut. Transcripts encoding netrin‐1 and ‐3 were not detected in the ENCDCs, but appeared after they had given rise to neurons. When these neurons were cocultured with cells expressing c‐Myc‐tagged netrin‐1, the neurons displayed netrin‐1, but not c‐Myc, immunoreactivity. Enteric neurons thus synthesize netrins. The extent to which neuronal netrin accounts for the dependence of the vagal sensory innervation on intrinsic neurons, remains to be determined. © 2010 Wiley Periodicals, Inc. Develop Neurobiol 71: 362–373, 2011
Analysis of NRG ‘legal highs’ in the UK: identification and formation of novel cathinones
Authors: Brandt Simon D. , Freeman Sally , Sumnall Harry R. , Measham Fiona , Cole Jon
Published: December 2010

A large number of cathinone derivatives have shown a wide range of bioactive properties, attracting great interest from communities associated with pharmaceutical research. Some of these derivatives have gained popularity as so‐called recreational ‘legal highs’ due to their availability on the Internet and high street shops. A previous study described the qualitative analysis of 24 ‘legal high’ Energy‐1 (NRG‐1) and NRG‐2 products obtained from 18 websites following the ban on mephedrone and derivatives in April 2010. The majority of these products contained a mixture of cathinones just carrying a new label. Here, three additional cathinone products have been detected; two from an NRG‐1 sample and one from an NRG‐3 sample. This report describes their identification. NRG‐1 sample 1 consisted of a mixture of 4 cathinones namely 4‐fluoromethcathinone (1), 1‐(3,4‐methylenedioxyphenyl)‐2‐(methylamino)pentan‐1‐one (pentylone, 2), 3,4‐methylenedioxy‐α‐pyrrolidinobutyrophenone (MDPBP, 3) and 3,4‐methylenedioxypyrovalerone (MDPV, 4). The sample labelled as NRG‐3 (mislabelled with the chemical structure of mephedrone) consisted of a mixture of 4‐methyl‐α‐pyrrolidinopropiophenone (MPPP, 5) and (2), whereas the remaining NRG‐1 sample 2 (also mislabelled with the chemical structure of mephedrone) consisted of a mixture of (2) and (3). Qualitative analyses were carried out by GC‐(EI/CI)‐MS, NMR spectroscopy and confirmation by preparation of standards. The preparation of brominated precursors carrying the 3,4‐methylenedioxyphenyl nucleus revealed extensive α,α‐dibromination: the mass spectral and NMR data of these intermediates are also presented and discussed. Copyright © 2010 John Wiley & Sons, Ltd.
Kinetic spectrophotometric methods for the determination of artificial sweetener (sucralose) in tablets
Authors: Youssef Rasha M. , Korany Mohamed A. , Khamis Essam F. , Mahgoub Hoda , Kamal Miranda F.
Published: December 2010

Two simple and sensitive kinetic spectrophotometric methods for the determination of sucralose are described. The first method is based upon a kinetic investigation of the oxidation reaction of the drug with alkaline potassium permanganate at room temperature for a fixed time of 30 min. The absorbance of the green coloured manganate ions produced was measured at 610 nm. The second method is based on the reaction of sucralose with cerium (IV) ammonium sulfate in the presence of perchloric acid with the subsequent measurement of the excess unreacted cerium (IV) ammonium sulfate at 320 nm at a fixed time of 30 min in a thermostated water bath at 60 ± 1 °C. This principle is adopted to develop a kinetic method for sucralose determination. The absorbance concentration plots in both methods were rectilinear over the range 4–16 and 10–30 µg ml−1, for the first and second methods, respectively. The different experimental parameters affecting the development and stability of the colours were carefully studied and optimized. The determination of sucralose by rate constant method, fixed concentration method, and fixed‐time method was also feasible with calibration equations obtained but the latter method was found to be more applicable. The two methods have been applied successfully to commercial tablets. Copyright © 2010 John Wiley & Sons, Ltd.
Screen and confirmation of PEG‐epoetin β in equine plasma
Authors: Chang Y. , Maylin G. M. , Matsumoto G. , Neades S. M. , Catlin D. H.
Published: December 2010

Methods have been developed to screen for and confirm darbepoetin alfa, recombinant human EPO, and methoxy polyethylene glycol‐epoetin ${\bf{\beta}}$ (PEG‐epoetin ${\bf{\beta}}$) in horse plasma. All three methods screen samples with an enzyme‐linked immunosorbent assay (ELISA) and confirm by liquid chromatography‐tandem mass spectrometry (LC‐MS/MS). This report focuses on PEG‐epoetin ${\bf{\beta}}$. The ELISA assay was able to detect PEG‐epoetin ${\bf{\beta}}$ at 0.02 ng/mL in 50 µL of horse plasma. Many samples had high background levels of immunoreactivity; however, introducing polyethylene glycol 6000 (PEG 6000) into the samples before the ELISA assay removed the high background and increased the apparent concentrations of PEG‐epoetin ${\bf{\beta}}$. In samples collected following the administration of 100 µg of PEG‐epoetin ${\bf{\beta}}$ by the intravenous (IV), intramuscular (IM) and subcutaneous (SC) routes, PEG‐epoetin ${\bf{\beta}}$ was detectable up to 72, 144, and 120 h, respectively. The samples were prepared for LC‐MS/MS analysis by extraction with anti‐rHuEPO‐antibodies‐coated Dynabeads followed by digestion with trypsin. The LC‐MS/MS confirmation method used the multiple reaction monitoring (MRM) scan mode to monitor four precursor‐product ion transitions of the EPO‐derived peptide T6. All four transitions of T6 were detectable with S/N > 3. The limit of confirmation for PEG‐epoetin ${\bf{\beta}}$ was 1.0 ng/mL in 2 mL of horse plasma. The method successfully confirmed the presence of PEG‐epoetin ${\bf{\beta}}$ in a sample collected from a Mircera®‐treated horse. Compared to PEG‐epoetin ${\bf{\beta}}$, better sensitivity was achieved for darbepoetin alfa and recombinant human EPO. Darbepoetin alfa was detected in horse plasma four days after IM administration of 100 µg. Copyright © 2010 John Wiley & Sons, Ltd.
Simultaneous spectrophotometric determination of diclofenac potassium and methocarbamol in binary mixture using chemometric techniques and artificial neural networks
Authors: Elkady Ehab F.
Published: December 2010

In this study, the simultaneous determination of diclofenac potassium (DP) and methocarbamol (MT) by chemometric approaches and artificial neural networks using UV spectrophotometry has been reported as a simple alternative to using separate models for each component. Three chemometric techniques—classical least‐squares (CLS), principal component regression (PCR), and partial least‐squares (PLS)—along with radial basis function‐artificial neural network (RBF‐ANN) were prepared by using the synthetic mixtures containing the two drugs in methanol. A set of synthetic mixtures of DP and MT was evaluated and the results obtained by the application of these methods were discussed and compared. In CLS, PCR, and PLS, the absorbance data matrix corresponding to the concentration data matrix was obtained by the measurements of absorbances in the range 260–310 nm in the intervals with Δλ = 0.2 nm in their zero‐order spectra. Then, calibration or regression was obtained by using the absorbance data matrix and concentration data matrix for the prediction of the unknown concentrations of DP and MT in their mixtures. In RBF‐ANN, the input layer consisting of 251 neurons, 9 neurons in the hidden layer, and 2 output neurons were found appropriate for the simultaneous determination of DP and MT. The accuracy and the precision of the four methods have been determined and they have been validated by analyzing synthetic mixtures containing the two drugs. The proposed methods were successfully applied to a pharmaceutical formulation containing the examined drugs. Copyright © 2010 John Wiley & Sons, Ltd.
PVC membrane sensor for potentiometric determination of iron (II) in some pharmaceutical formulations based on a new neutral ionophore
Authors: Abounassif M. A. , Al‐Omar M. A. , Amr A.‐G. E. , Mostafa G. A. E.
Published: December 2010

A novel poly (vinyl chloride) PVC membrane sensor for Fe2+ ions is described. The sensor is based on the use of newly synthesized chiral 2,6‐bis‐(carboxamide methyl ester)pyridine derivative as neutral ionophore in plasticized PVC membrane. The sensor display a fast, stable and near‐Nernstian response over a relative wide ferrous concentration range (1 × 10−3 to 6 × 10−6 M), with cationic slope of 31.5 ± 0.5, mV per concentration decade over a pH range of 5.0–9.0. The direct determination of 0.25–56.0 µg/ml of ferrous in aqueous solution shows an average recovery of 98.5% and a mean relative standard deviation of 1.5% at 20.0 µg/ml. The sensor displays long life‐span, long‐term stability, high reproducibility, and short response time. Selectivity coefficients for Fe(II) relative to a number of interfering substances were investigated. The sensor shows high significantly for Fe2+ over Fe,3+ Cu,2+ Zn,2+ Cd,2+ Hg,2+ Pb,2+ Ni,2+ Co,2+ Mn,2+ Al,3+ alkaline earth and alkali metal ions. The sensor is successfully applied for measurement of ferrous in drug formulations. The results obtained for the determination of ferrous using the proposed sensor are comparable favourably with those obtained using the spectrophotometric method. Copyright © 2010 John Wiley & Sons, Ltd.
A 2‐Pyrazoline‐Functionalized Zinc Complex: Available N–AgI Interaction Modulating Its Fluorescence Properties
Authors: Zhang Hui‐hui , Dou Wei , Liu Wei‐sheng , Tang Xiao‐liang , Qin Wen‐wu
Published: December 2010

A readily available fluorescent sensor [Zn(1‐phenyl‐3‐methyl‐5‐hydroxy‐4‐pyrazolyl phenyl ketone benzoyl hydrazone)2] (Zn‐PMPB) with simple and conformationally adaptable receptors for silver cation has been designed. The central Zn2+ ion and ligands in the complex have a synergistic effect on binding interactions with the Ag+ ion. Zn‐PMPB was characterized in detail by various spectroscopic techniques and single‐crystal X‐ray diffraction. Its photochemical properties for detecting the Ag+ ion in HEPES buffered (10 mM, pH 7.1) MeOH/H2O (4:6) solution are described. This fluorescent sensor has a negligible quantum yield (0.0011) due to deactivation of solvent hydrogen bonding, whereas a significant increase in fluorescence is observed upon complexation with Ag+. NMR titration and UV/Vis spectroscopy suggest that the Ag+ ions bind to the N2 atom in the pyrazoline group in Zn‐PMPB, which facilitates the intramolecular charge transfer emission of pyrazoline.