bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stirred vessel cultures of rat brain cells aggregates: Characterization of major metabolic pathways and cell population dynamics
Authors: Santos Sónia Sá , Leite Sofia B. , Sonnewald Ursula , Carrondo Manuel J.T. , Alves Paula M. 
Published: July 2007

AbstractWe report a study on neural metabolism of long‐term three‐dimensional cultures of rat embryonic brain cells in stirred vessels. Our experimental setup was optimized to keep viable aggregate cultures with neuronal maintenance for up to 44 days. Results show that aggregate size and shape could be hydrodynamically controlled depending on the impeller design, avoiding necrotic centers or significant losses in cell viability. Aggregates were composed mainly of neurons until day 16, whereas an effective growth of the glial population was observed after day 21. Cell metabolic status was evaluated by quantification of several metabolites in the culture medium; amino acid metabolism was used as a marker of metabolic interrelationships between neural cell types. Furthermore, 13C‐NMR spectroscopy was used on day 31 to explore specific metabolic pathways: incubation with [1‐13C]glucose for 45 hr produced an increase in label incorporation in extracellular alanine, lactate, and glutamine, reflecting mainly astrocytic metabolism. The contribution of anaplerotic vs. oxidative pathways for glutamine synthesis was determined: a 92% reduction in the pyruvate carboxylase flux during the first 41 hr of incubation suggested a decrease in the need for replacing tricarboxylic acid cycle intermediates. We believe that our data corroborate the aggregating cultures as an attractive system to analyze brain cell metabolism being a valuable tool to model metabolic fluxes for in vitro brain diseases. © 2007 Wiley‐Liss, Inc.
Cellular Zn2+ chelators cause “dying‐back” neurite degeneration associated with energy impairment
Authors: Yang Yi , Kawataki Taku , Fukui Koji , Koike Tatsuro 
Published: July 2007

AbstractMost cellular zinc is tightly associated with metalloproteins and other Zn2+‐dependent proteins, which along with cellular Zn2+ compartments may coordinately regulate cytoplasmic free Zn2+ levels in the picomolar range. Moreover, Zn2+‐containing endosomes or protein complexes appear to move along axons or dendrites, suggesting a dynamic mechanism for trafficking, exchanging, or scavenging Zn2+ and/or Zn2+ protein complexes in neurons. It is therefore interesting to examine whether cellular Zn2+ levels might alter neurite integrity and dynamics. Here we show that membrane‐permeable zinc chelators, including 1,10‐phenanthroline, N,N,N′,N′‐tetrakis‐(2‐pyridylmethyl)‐ethylenediamine (TPEN), and zinquin, selectively elicit axon and dendrite degeneration but leave the cell body intact in sympathetic neurons. The process begins distally and then moves retrogradely, with a distinct “dying‐back” pattern. An inactive isomer of 1,10‐phenanthroline failed to cause neuite degeneration, and these chelators mediated their effects by selectively chelating Zn2+, but not other metals. Moreover, neurite degeneration was associated with a decrease in neuritic ATP levels and was caused by energy failure, because an exogenous supply of nicotinamide adenine dinucleotide (NAD) or its precursor nicotinamide suppressed the degeneration by delaying axonal ATP reduction caused by Zn2+ depletion. Blockage of autophagy by 3‐methyladenine provided partial protection against degeneration of terminal axons or dendrites; there was, however, no obvious alteration in that of medial portions. Collectively, our results show that cellular Zn2+ depletion induces a “dying‐back” degeneration characterized by an NAD‐ and autophagy‐dependent process, independently of neurite elongation dynamics. © 2007 Wiley‐Liss, Inc.
Separation and quantification of 9‐(alkylthio)acridines by capillary micellar electrokinetic chromatography and capillary liquid chromatography
Authors: Nejmanová Jana , Coufal Pavel , Bosáková Zuzana , Suchánková Jana , Tesarová Eva 
Published: July 2007

AbstractVarious thioacridine derivatives are potential chemotherapeutics against various diseases which are intensively synthesized, characterized, and investigated by many research groups. Efficient, fast, and reliable separation and quantification methods for their analysis are still to be developed. MEKC and capillary LC (CLC) were applied for the separation and quantification of five highly hydrophobic, weakly basic, and structurally similar 9‐(alkylthio)acridines. Since the common anionic and cationic surfactants failed to separate the strongly hydrophobic thioacridines by MEKC, sodium cholate was used in an alkaline BGE and successfully employed for their fast separation. In CLC, the weakly basic nature of the thioacridines necessitated use of LiChrosorb RP‐select B sorbent as the stationary phase, which combined with a very simple mobile phase methanol/water yielded an efficient chromatographic separation system. Both, the MEKC and CLC optimized separation methods were then applied to quantify the thioacridines within a concentration range of 1.0×10–5–1.0×10–3 mol/L and the obtained experimental results were critically compared. In practical terms, the MEKC analytical method can quantify the analytes much faster but with a lower reliability while the CLC method performs slower analysis with a higher repeatability of the experimental results.
Simultaneous determination of four active constituents in the roots of Scrophularia buergeriana by HPLC‐DAD and LC‐ESI‐MS
Authors: Lee Mi Kyeong , Choi Ok‐Gyung , Park Jin‐Ho , Cho Hi‐Jae , Ahn Mi‐Jeong , Kim Seung Hyun , Kim Young Choong , Sung Sang Hyun 
Published: July 2007

AbstractThe chemical profile of four main bioactive constituents including harpagoside (HS), 8‐O‐(E‐p‐methoxycinnamoyl)harpagide (HG), E‐cinnamic acid (CA), and E‐p‐methoxycinnamic acid (MCA), in the extract of Scrophularia buergeriana was studied using HPLC‐diode array detector‐electrospray‐MS (HPLC‐DAD‐ESI‐MS). The HPLC‐DAD conditions were optimized for the simultaneous analysis of these four compounds. This method was validated in terms of specificity, linearity (r2 >0.9998), precision (< 2.0% RSD), and recoveries (94.4–115.1%). The LOD of these compounds were ranged from 5.9 to 37.8 ng. In addition, the main compounds in S. buergeriana and S. ningpoensis were quantified using this validated method, which resulted in significant difference in the contents of these compounds between the species.
Development of an HPLC method for the monitoring of tricyclic antidepressants in biofluids
Authors: Samanidou Victoria F. , Nika Maria K. , Papadoyannis Ioannis N. 
Published: July 2007

AbstractA simple, rapid and sensitive HPLC method was developed and validated for the determination of four tricyclic antidepressants (TCAs): amitriptyline, doxepin, clomipramine (CLO) and imipramine, in pharmaceutical formulations and biological fluids. A Kromasil C8 analytical column (250×4 mm, 5 μm) was used for the separation, with a mobile phase consisting of 0.05 M CH3COONH4 and CH3CN (45:55 v/v) delivered at 1.5 mL/min isocratically. Quantification was performed at 238 nm, with bromazepam (1.5 ng/μL) as the internal standard. The determination of TCAs in blood plasma was performed after protein precipitation. Urine analysis was performed by means of SPE using Lichrolut RP‐18 Merck cartridges providing high absolute recoveries (> 94%). Direct analysis of urine was also performed after two‐fold dilution. The developed method was fully validated in terms of selectivity, linearity, accuracy, precision, stability and sensitivity. Repeatability (n = 5) and between‐day precision (n = 5) revealed RSD <13%. Recoveries from biological samples ranged from 91.0 to 114.0%. The absolute detection limit of the method was calculated as 0.1–0.6 ng in blood plasma and 0.2–0.5 ng in extracted urine or 0.4–0.7 in diluted urine. The method was applied to real samples of plasma from a patient under CLO treatment.
Cad compatible accurate models of microwave passive lumped elements for mmic applications
Authors: Sadhir Virender K. , Bahl Inder J. , Willems David A. 
Published: July 2007

AbstractThis article presents accurate measurement‐based models derived from measured S‐parameters of passive circuit elements which include inductors, thin‐film resistors, interdigital and MIM capacitors, via holes, and airbridges for use in the computer‐aided design of monolithic microwave integrated circuits (MMICs). The thru‐reflect‐line (TRL) calibration method is employed to accurately measure the S‐parameters of the passive elements. Some of the models are scalable for different substrate thicknesses and substrate dielectric constant values as they are based on microstrip line theory. © 1994 John Wiley & Sons, Inc.
DECnet/OSI—Part 3: DECnet/OSI Network Management
Authors: Snellen David 
Published: July 2007

AbstractIn the previous articles on DECnet/OSI the focus has been on the technical aspects of Digital's implementation, alias Advantage Networks. The openness of Advantage Networks is both good and bad. It's good because you have the freedom to mix and match network devices to fit your specific needs. It's bad because a heterogeneous network environment will be very difficult to manage. In this article the discussion is on Digital's concept of managing a DECnet/OSI network management.
CSMA/CD Network Problem Threshold
Authors: Gejji Raghvendra R. 
Published: July 2007

AbstractCSMA/CD network transmission errors such as collisions, CRC errors, misalignment, etc. are statistical in nature. Although errors can vary randomly, a high level of errors does indicate specific network problems (e.g. equipment failure). This paper examines the random nature of collisions theoretically as well as from actual statistics, and establishes a threshold above which a network problem is indicated with a high probability.
A Generic Management System for Heterogeneous Networks
Authors: Bhushan Bharat , Patel Ahmed 
Published: July 2007

AbstractThis paper summarizes the key requirements for the system, presents an object‐oriented model of the heterogeneous networks, and gives a brief description of the main functional parts of the system. The model discussed in this paper consists of object classes representing protocol layers such as TCP/IP layers or the data link layer of the X.25 protocol.
Solar‐powered air conditioner
Authors: Takeoka A. , Fukuda Y. , Suzuki M. , Hasunuma M. , Sakoguchi E. , Tokizaki H. , Kouzuma S. , Waki M. , Ohnishi M. , Nakano S. , Kuwano Y. 
Published: July 2007

AbstractWe have successfully developed and industrialized a solar‐powered air conditioner that operates through a combination of photovoltaic (PV) arrays and commercial power supplies. In order to achieve the most efficient operation possible from a one‐horsepower inverter‐type household air conditioner, we selected a PV array output of 540 W under standard test conditions, based on single‐day power use patterns for air conditioners as well as on solar cell output patterns.When using a 540‐W PV array, we have shown that the system can supply at least 90% of the power consumed by an air conditioner during peak power periods in summer. We have confirmed that on average the power generated by the PV array can satisfy at least 50% of the power consumed by an air conditioner in summer. We also confirmed that the system functions according to system design specifications. There is little doubt that the introduction and widespread use of this system will play an important role in reducing peak power energy requirements in summer.
Metastability of phosphorus and boron in hydrogenated amorphous silicon
Authors: Nebel C. E. , Street R. A. , Johnson N. M. , Jackson W. B. 
Published: July 2007

AbstractThermodynamic equilibration kinetics of phosphorus‐ and boron‐doped hydrogenated amorphous silicon (a‐Si:H) are explored using dark conductivity measurements. the equilibration kinetics of phorphorus‐ and boron‐doped a‐Si:H are different and there is a strong dependence on the deposition temperature (Ts). Small variations in temperature of the semiconductor cause variations in active dopant concentration, which affects the conductivity. the transformation of phorphorus into the electronically active phase (activation) follows a stretched exponential time dependence with a temperature‐independent dispersion parameter, β, of 0.85, whereas the transformation into the electronically passive bonding configuration (passivation) is also a stretched exponential but with β ⩽ 0.8. the kinetics of boron metastability are similarly a stretched exponential, but with equal β values for activation and passivation. the time constant, τ, to achieve equilibrium for both transformations is thermally activated with energies Eact ∽ 1.1 eV for phosphorus and boron. an increase in Ts leads to an increase of Eact. the data are discussed and interpreted based on the hydrogen migration model.
Control of particulate and gas emissions in photovoltaic module manufacture
Authors: Fthenakis V. M. , Moskowitz P. D. 
Published: July 2007

AbstractEmissions of toxic gases and particulates from photovoltaic module R&D and manufacturing facilities may need treatment to meet current or anticipated regulations. In this study currently available pollution‐control options (e.g. filters, scrubbers, adsorption columns, combustion devices) are reviewed for their suitability to treat emissions (e.g. HCl, HF, Cl2, H2Se, SiH2, SiH2Cl2, AsH3, PH3, Cd and As compounds) from photovoltaic cell laboratories and production facilities. For small emission flow rates (e.g. > 100 l min−−1) and small to moderate particulate loads (e.g. <2 mg l−−1), on‐line filters can economically collect fumes and other particulates generated in the deposition chambers, whereas adsorption columns can very effectively treat toxic hydrates (e.g. AsH3, PH3, H2Se) at concentrations up to 1% (up to 10% for very small flow rates, e.g. <11 min−−1). For large emission flow rates, (e.g. > 100 1 min−−1), very low concentrations of hydrates can still be treated effectively with adsorption. Combined control of particulates and hydrates can be achieved by a bag‐house followed by a multistage scrubber; when the concentration of hydrates is relatively high, a thermal oxidation unit should precede the bag‐house scrubber for effective control. Finally, multicomponent mixtures can be treated either by wet scrubbing or combustion, depending on the mixture composition.
The dynamics of economic growth and political instability in developing countries
Authors: Saeed Khalid 
Published: July 2007

AbstractAccelerating the rate of economic growth in developing countries has been an important aim of almost all development policies implemented over the past three decades. Experience has shown that such growth is often not sustainable and is likely to be interrupted by violent political changes. This paper attempts to identify the organizational factors that limit economic growth and create conditions conducive to the outbreak of political violence. A system dynamics model of the sociopolitical organization of a developing country is presented, and the model's behavior is studied using computer simulation.
Coupling DYNAMO and optimization software
Authors: Gustafsson Leif , Wiechowski Miroslaw 
Published: July 2007

AbstractNotes and Insights is a forum for discussion and debate about current issues in the philosophy and application of the system dynamics approach, and a marketplace for the exchange of information about current research, policy issues, and teaching experiences. Manuscripts treating material particularly suited to presentation in short form (less than 2,000 words) should be sent to Erich Zahn, Betriebswirtschaftliches Institut, Universität Stuttgart, Herdweg 23, D‐7000 Stuttgart 1, West Germany.
Migratory dynamics of interacting subpopulations: Regular and chaotic behavior
Authors: Reiner Rolf , Munz Martin , Weidlich Wolfgang 
Published: July 2007

AbstractWe demonstrate that different kinds of dynamic behavior may occur in a general migration system. The deterministic nonlinear coupled mean value equations are introduced. The intergroup and intragroup interactions of the subpopulations determine the dynamics of the system. First, the route to chaotic motion in the case of two subpopulations migrating between three regions is briefly presented. In the special case of three interacting sub‐populations migrating between three regions, we then show in detail that all kinds of attractors (fixed points, limit cycles, and strange attractors) exist. Characteristics of the motion, namely the Fourier spectrum, Lyapunov exponents, and the fractal dimension of the attractors, are analyzed. Finally, we discuss the relevance of the results for real migration systems.
Aging, contraction, and cohesion in a religious order: A policy analysis
Authors: Gaynor Alan K. , Morrow Jean , Georgiou Stelios N. 
Published: July 2007

AbstractThis article is a study of problems of contraction and cohesion in the Order of the Servants of Mary. Focusing on the history of the Order since the Second Vatican Council (1962‐1965), it seeks to uncover the dynamics that underlie these problems and to recommend broad directions for future policy. The logical level of the policy recommendations conforms with that of the analysis, which concentrates on a few highly aggregated driving forces.
The dynamics of managing a life insurance company
Authors: Doman Andrew , Glucksman Maurice , Mass Nathaniel , Sasportes Michel 
Published: July 2007

AbstractThis article reports the findings of an internal McKinsey research and development project designed to test the value of applying system dynamics thinking to the life insurance industry. The aim was to understand better how management decisions and actions can affect the success or failure of a typical direct sales life company. The study compared the evolution over 20 years of two companies, which in the interests of confidentiality, we will refer to as “Tortoise Life” and “Hare Life”. Starting out in 1975 from virtually identical competitive positions, Tortoise Life has become one of the U.K.'s most successful life companies, while Hare Life had to be rescued from near insolvency in 1989. We found system dynamics a powerful means of identifying which managerial actions had accounted for the extraordinary divergence of the two companies. The lessons learned include many counterintuitive insights that have relevance for any life‐company manager. Through simulation we were able to isolate which management actions made the difference to long‐term performance. In particular, we show how attempts to exceed the maximum sustainable growth rate specific to any individual company can lock it into a slow but relentless spiral of decline, from which there is little hope of escape. This growth ceiling can be quantified and we also identify a number of long range early warning signs. Consequently, we believe that our conclusions are likely to change the way life companies are managed in the future.
Esophageal obstruction—prenatal detection rate and outcome
Authors: Brantberg A. , Blaas H‐G. K. , Haugen S. E. , Eik‐Nes S. H. 
Published: July 2007

AbstractObjectivePrenatal diagnosis of esophageal obstruction is believed to improve the outcome for the affected newborn. However, the prenatal detection rate is only 10–40%, the diagnosis is usually not made before the third trimester and the false‐positive rate has been high. This study investigated the prenatal detection rate and time of prenatal diagnosis at our center and its influence on outcome. In addition, incidence, detection rate and accuracy of the diagnosis in a large non‐selected population were determined.MethodsAll cases diagnosed pre‐ or postnatally with esophageal obstruction and examined prenatally by ultrasound at the National Center for Fetal Medicine in Norway during 1987–2004 were evaluated.ResultsOf 48 cases with esophageal obstruction, 21 (44%) were diagnosed prenatally (median, 32 + 0 weeks). All 21 had a small or empty stomach, 20/21 (95%) had polyhydramnios and 9/21 (43%) had a visible esophageal pouch. Associated anomalies were present in 38/48 cases (79%). The karyotype was abnormal in 11/48 cases (23%). Ten (21%) pregnancies with lethal fetal conditions were terminated. Two fetuses died in utero. Ten infants with associated anomalies died within 3 months after birth. The 26/48 (54%) survivors included 16/21 cases with a prenatal diagnosis of esophageal obstruction and 9/10 cases with isolated esophageal obstruction.ConclusionsThe clinical signs of polyhydramnios were the most important factors for prenatal detection of esophageal obstruction. Consequently, the time of diagnosis was late and the detection rate was low (44%). An increased awareness of the possibility of esophageal obstruction, leading to targeted examinations whenever the suspicion is raised during pregnancy, might improve the prenatal detection rate and thereby provide a possibility to improve the outcome. Of the cases with isolated esophageal obstruction, 90% survived, irrespective of prenatal diagnosis. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
Sinonasal hybrid tumour involving the anterior skull base
Authors: Mazita A , Gendeh B S , Zainal A I 
Published: July 2007

AbstractObjective:We report a rare case of sinonasal hybrid tumour within an inverted papilloma.Method:The patient's case history and course of management are presented. The relevant medical literature are reviewed and discussed.Results:A 60-year-old man presented with unilateral nasal obstruction associated with anosmia. An ENT examination revealed a unilateral, left nasal mass. A provisional diagnosis of inverted papilloma was made. The patient underwent a transnasal endoscopic excision of the tumour, which was unfortunately complicated by a cerebrospinal fluid leak. Further treatment of this patient is described. We highlight the features of associated malignancy in inverted papilloma, and the importance of thorough histopathological examination of tissue specimens.Conclusion:Treatment of inverted papilloma with limited involvement of the skull base can be successfully achieved by endoscopic excision. A high index of clinical suspicion, together with meticulous histopathological examination, will enable diagnosis of associated malignancy. This will ensure that appropriate adjuvant treatment is given, resulting in a good clinical outcome.
A biharmonic problem with constraint involving critical Sobolev exponent
Authors: Guedda M. , Hadiji R. , Picard C. 
Published: July 2007

We are concerned with the following minimization problems,

where Ω ⊂ RN, N > 4, is a smooth bounded domain, qc = 2N/(N − 4), ϕ ∈ C(Ω) ∩ Lqc(Ω) and . We show that, for ϕ ≢ 0, each infimum is achieved. Under suitable conditions on ϕ, we establish the following gap phenomenon,

for q ≤ qc.Moreover, we study the limit behaviour of the minimizers, as q goes to qc, in the case ϕ ∈ H(Ω).
Hardy spaces on ZN
Authors: Boza Santiago , Carro María J. 
Published: July 2007

The work of Coifman and Weiss concerning Hardy spaces on spaces of homogeneous type gives, as a particular case, a definition of Hp(ZN) in terms of an atomic decomposition.Other characterizations of these spaces have been studied by other authors, but it was an open question to see if they can be defined, as it happens in the classical case, in terms of a maximal function or via the discrete Riesz transforms.In this paper, we give a positive answer to this question.