bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design of packed distillation columns. I. Pressure drop through packed distillation columns
Authors: Hands C. H. G. , Whitt F. R. , Gregory K. S. 
Published: July 2007

AbstractPlots of water‐rate and packing‐shape correction factors for four commonly used sizes of Raschig rings to use with a modified Fanning equation are given. These are for fluid rates commonly associated with distillation, as distinct from absorption.Experimental evidence is given to show the magnitude of the error involved in applying the results obtained with an air/water system to calculations concerning distillation systems.
Manufacture of algal chemicals. U. Production of alginates from brown marine algae
Authors: Bashford L. A. , Thomas R. S. , Woodward F. N. 
Published: July 2007

AbstractA process for the production from the brown seaweeds Laminaria digitata and Ascophyllum nodosum of calcium alginate of reasonably constant ‘grade’ (50‐100 centistokes) and composition (approx. 95% calcium alginate, 1·3% ‘weed residue’) has been developed on the 25‐1b. wet weed batch scale. Certain aspects of the process have been further examined on the large laboratory scale with particular reference to the initial water‐washing and acid‐leaching stages. Under the best conditions found yields of 85% and upwards have been obtained.
Improved syntheses in the pyrimidine series. 1. The use of pyrimidine‐thiols
Authors: Brown D. J. 
Published: July 2007

AbstractSyntheses suitable for large laboratory‐scale working, are described for thiocytosine, cytosine, 4‐hydroxypyrimidinc, 4‐amino‐pyrimidine, 2 : 4‐ and 4: 6‐diaminopyrimidincs, uracil, 4‐amino‐6‐hydroxypyrunidine and several of their derivatives. The majority of these syntheses start from thiouracil, which has recently become plentiful; all involve replacement of a thiol‐group by −NH2, ‐OH or‐H.
The solubility of lead in zinc sulphate solutions
Authors: Barker C. W. , Powell J. , Young R. S. 
Published: July 2007

AbstractThe solubility of lead in zinc sulphate solutions was determined over the range of zinc concentration from 75 to 125 g./l., acid concentrations from OT to 75 g./l., and temperatures of 20°‐30° c. In this range of variables normally encountered in electrolytic zinc refineries the lead solubility varied from 4.3 to 6.8 mg./l. It decreased with increase in acid concentration, increased with increase of temperature, and was nearly unaffected by zinc concentration.
The control of foaming. I. The mode of action of chemical anti‐foams
Authors: Pattle R. E. 
Published: July 2007

AbstractA large number of substances were tested for ability to destroy the foam on four(different foaming aqueous solutions. The ability or inability of the anti‐foams to spread on the foaming liquid was also studied.It is concluded that anti‐foams act by displacing from the surface the substance causing the foaming (or, in salt solutions, preventing negative adsorption). They may do this either by dissolving in the foam liquid or bespreading over its surface.) The causes of the strong, correlation (found) between foam‐killing and spreading are discussed.
A portable water‐flow gas calorimeter
Authors: Gooderham W. J. 
Published: July 2007

AbstractA new form of water‐flow gas calorimeter is described in which gas volumes are read with a soap‐film meter, and water volumes on a burete. The calorimeter is a silvered and evacuated resistance‐glass vessel. A new type of pump is used to supply air to the burner. The gross calorific value of a gas can be obtained in to minutes if the rates of flow of air, gas and water arc set correctly. The calorimeter was designed to give results correct to the nearest I3.Th.U. but an accuracy greater than this may he possible.
Noradrenergic regulation in mouse supraoptic nucleus involves a nitric oxide pathway only to regulate arginine‐vasopressin expression and not oxytocin expression
Authors: Maolood Nasren , Grange‐Messent Valérie , Raison Danièle , Hardin‐Pouzet Hélène 
Published: July 2007

AbstractNoradrenalin (NA) regulates the expression of arginine‐vasopressin (AVP) and oxytocin (OT) by magnocellular neurons in the supraoptic nucleus (SON) of the hypothamalus. Nitric oxide (NO) may be one of the factors involved in the NA signaling pathway regulating AVP and OT expression. To test this possibility, we used an ex vivo experimental model of mouse hypothalamus slices. Increases in AVP and OT levels in the SON were detected by immunohistochemistry and immunoenzyme assays after 1 hr and 4 hr incubations with NA (10−4 M). There was also an increase in the expression and activity of neuronal NOS and inducible NOS in the SON as assessed by immunohistochemical and histoenzymological analysis of NADPH‐diaphorase, whereas endothelial NOS was undetectable. To specify the role of NO, the slices were treated with NA and L‐arginine methyl ester (L‐NAME, an NOS inhibitor; 3 μM). This treatment for 1 hr abolished the NA‐induced increase in AVP. Treatment with sodium nitroprusside (SNP, an NO donor; 0.1 mM) increased AVP levels, confirming that NO regulates AVP expression. Addition of 1 mM EGTA during the incubation with NA reduced the AVP increase by half, indicating that both nNOS and iNOS activities are involved in the regulation. A 1‐hr treatment with L‐NAME did not prevent the increase in OT induced by NA; similarly, treatment with SNP had no effect. These findings show that NO is involved in the regulation of AVP expression by NA and that NA control of OT expression is independent of NO. © 2007 Wiley‐Liss, Inc.
Dual effect of adenovirus‐mediated transfer of BMP7 in mixed neuron‐glial cultures: Neuroprotection and cellular differentiation
Authors: Tsai May‐Jywan , Weng Ching‐Feng , Shyue Song‐Kun , Liou Dann‐Ying , Chen Chien‐Hung , Chiu Chuan‐Wen , Yang Tzu‐Hsuan , Pan Hsu‐An , Liao Roanna I‐Hsin , Kuo Huai‐Sheng , Huang Ming‐Chao , Huang Wen‐Cheng , Hoffer Barry J. , Cheng Henrich 
Published: July 2007

AbstractBone morphogenetic proteins (BMPs), members of the TGF‐β superfamily, have been implicated in nervous system development and in response to injury. Previous studies have shown that recombinant BMP7 can enhance dendritic growth and protect cultured neurons from oxidative stress. Because of the presence of extracellular BMP antagonists, BMP7 seems to act locally. Therefore, the present study uses BMP7 overexpression using adenovirus (Ad)‐mediated gene transfer to examine its effect in mixed neuronal cultures. Enhanced BMP7 expression selectively induces neuronal CGRP expression in a time‐dependent manner. BMP7 overexpression not only significantly protects cultures from H2O2 toxicity but reduces lipopolysaccharide (LPS) stimulation. Concurrently, it profoundly reduces microglial numbers, but increases oligodendroglial and endothelial cells. Together, low‐dose and continuously expressed BMP7 is both neuroprotective and differentiation‐inductive. © 2007 Wiley‐Liss, Inc.
Aging attenuates dynactin–dynein interaction: Down‐regulation of dynein causes accumulation of endogenous tau and amyloid precursor protein in human neuroblastoma cells
Authors: Kimura Nobuyuki , Imamura Osamu , Ono Fumiko , Terao Keiji 
Published: July 2007

AbstractImpaired axonal transport may promote pathogenesis in neurodegenerative disorders, such as Alzheimer's disease (AD). We previously showed that tau, amyloid precursor protein (APP), and intracellular amyloid β‐protein (Aβ) accumulate in the nerve‐ending fraction of aged monkey brains, perhaps because of impaired axonal transport. In the present study, we assessed age‐related changes of axonal transport motor proteins in aged monkey brains. Western blotting showed that kinesin, dynein, and dynactin (DYN) localizations dramatically changed with aging, and dynein level in nerve‐ending fractions increased significantly. Coimmunoprecipitation analyses showed that DYN–dynein intermediate chain (DIC) interactions decreased, suggesting that age‐related attenuation of this interaction may cause the impairment of dynein function. Moreover, RNAi‐induced down‐regulation of DIC in human neuroblastoma cells caused endogenous tau and APP to accumulate, and their subcellular localizations were also affected. Our findings suggest that aging attenuates DYN–DIC interaction, representing one of the risk factors for age‐related impaired dynein function and even for accumulation of disease proteins. © 2007 Wiley‐Liss, Inc.
Molecular chaperone‐mediated tau protein metabolism counteracts the formation of granular tau oligomers in human brain
Authors: Sahara N. , Maeda S. , Yoshiike Y. , Mizoroki T. , Yamashita S. , Murayama M. , Park J.‐M. , Saito Y. , Murayama S. , Takashima A. 
Published: July 2007

AbstractIntracellular accumulation of filamentous tau proteins is a defining feature of neurodegenerative diseases termed tauopathies. The pathogenesis of tauopathies remains largely unknown. Molecular chaperones such as heat shock proteins (HSPs), however, have been implicated in tauopathies as well as in other neurodegenerative diseases characterized by the accumulation of insoluble protein aggregates. To search for in vivo evidence of chaperone‐related tau protein metabolism, we analyzed human brains with varying degrees of neurofibrillary tangle (NFT) pathology, as defined by Braak NFT staging. Quantitative analysis of soluble protein levels revealed significant positive correlations between tau and Hsp90, Hsp40, Hsp27, α‐crystallin, and CHIP. An inverse correlation was observed between the levels of HSPs in each specimen and the levels of granular tau oligomers, the latter of which were isolated from brain as intermediates of tau filaments. We speculate that HSPs function as regulators of soluble tau protein levels, and, once the capacity of this chaperone system is saturated, granular tau oligomers form virtually unabated. This is expressed pathologically as an early sign of NFT formation. The molecular basis of chaperone‐mediated protection against neurodegeneration might lead to the development of therapeutics for tauopathies. © 2007 Wiley‐Liss, Inc.
Determination of gastrodin and vanillyl alcohol in Gastrodia elata Blume by pressurized liquid extraction at room temperature
Authors: Ong Eng Shi , Heng Ming Yuan , Tan Swee Ngin , Hong Yong Jean Wan , Koh Huijing , Teo Chin Chye , Hew Choy Sin 
Published: July 2007

AbstractPressurized liquid extraction (PLE) at room temperature with a laboratory‐assembled system was applied for the extraction of gastrodin (GA) and vanillyl alcohol (VA) in Gastrodia elata Blume. The proposed system setup for this current work was simpler as no heating and backpressure regulator was required. Extraction with PLE was carried out dynamically at a flow rate of 1.5 mL/min, at room temperature, under an applied pressure of 10–20 bars with an extraction time of 40–50 min. The extraction efficiencies of the proposed method using 20% aqueous ethanol were compared with heating under reflux using organic solvents such as methanol and ethanol/water (20:80) for different batches of medicinal plant materials. For the determination of GA and VA in G. elata Blume, the extraction efficiencies of PLE at room temperature were observed to be comparable with heating under reflux. The method precision was found to vary from 1.6 to 8.6% (RSD, n = 6) on different days. The marker compounds present in the various medicinal plant extracts were determined by gradient elution HPLC and HPLC/MS/MS. Our work demonstrated the possibility of implementation of PLE at room temperature and the advantages of minimizing the use of organic solvents in the extraction process.
The fractal calibration method applied to the characterization of polymers in solvent mixtures and in mixed gel packings by SEC
Authors: Porcar Iolanda , García‐Lopera Rosa , Abad Concepción , Campos Agustín 
Published: July 2007

AbstractThe size‐exclusion chromatographic (SEC) behaviour of different solvent/polymer systems in three packing sets has been analysed from fractal considerations. The three‐column sets studied are specifically formed by: (i) ‘pure’ μ‐styragel, (ii) ‘mixed’ TSK Gel HHR + XL + HR and (iii) mixed TSK Gel HXL + HR + XL. The experimental data reveals that in most of the systems assayed the classical universal calibration (UC) is not fulfilled, denoting the existence of secondary effects accompanying the main SEC mechanism. In order to obtain an accurate characterization of different polymers eluted in solvent mixtures and/or mixed packings, the use of a reliable and trusted calibration curve is required. In this sense, two alternative procedures have been analysed: the specific (SC) and the fractal (FC) calibrations. The results have evidenced that the use of the FC instead of the classical universal method diminishes up to nine times (in the case of the μ‐styragel set) the mean deviation on the calculated molar mass with respect to the value given by the supplier. In the case of TSK Gel‐based sets, the mean deviation is reduced to the half. The SC curve made with standards of the sample under study also reduces the mean deviation values but needs a broad set of narrow standards, whereas the fractal approach only needs one polymeric sample to build up the calibration curve.
Characteristics of a cylindrical disk‐loaded slow‐wave structure found by theoretical, experimental, and computational techniques
Authors: Wallett Thomas M. , Qureshi A. Haq 
Published: July 2007

AbstractThe dispersion characteristics and interaction impedances of a disk‐loaded cylindrical waveguide structure were investigated using theoretical, computer, and experimental techniques. Satisfactory agreement has been demonstrated between the experimentally determined values, the results obtained theoretically, and the computer‐generated values using the ARGUS and SOS computer codes. © 1994 John Wiley & Sons, Inc.
Full‐wave convergence analysis of microstrip transmission parameters
Authors: Carroll James Mason , Chang Kai 
Published: July 2007

AbstractFull‐wave electromagnetic simulators have enabled microwave designers to simulate complex geometries which sometimes cannot be done by conventional computer‐aided design (CAD) nodal simulators. However, designers should pay close attention to how the numerical implementation of the full‐wave analysis can affect the results of the electromagnetic simulation. This study uses various modeling parameters to determine the convergence of a GaAs microstrip's simulated transmission line characteristics. A commercially available program, Sonnet's “EM,” was used for the analysis but the results can be generalized for any full‐wave analysis. This article explores the limits of Sonnet as well as showing that a designer must use a convergence analysis to prove the validity of an electromagnetic simulation. © 1994 John Wiley & Sons. Inc.
A GaAsFET spice model for active filter tuning purposes
Authors: Richard William D. , Gregory Robert O. 
Published: July 2007

AbstractModeling GaAsFETs in MMIC active filter circuits at microwave frequencies is hampered by the complex dependence of the small‐signal model elements on bias voltages, bias currents, and frequency. Several authors have attempted an improved GaAsFET model by starting with the Curtice model of the device. This article takes a different path in developing a model for SPICE usage: a Curtice model GaAsFET is used to set the DC bias conditions; based upon these bias conditions, values for each small‐signal element are calculated. This model has been found to be especially useful for tuning studies of MMIC active filters. Results are presented for an MMIC active bandpass filter based on a twin‐tee notch filter. © 1994 John Wiley & Sons, Inc.
Itrative design‐oriented analysis method for class‐ab high‐efficiency microwave power amplifiers
Authors: Giannini Franco , Leuzzi Giorgio , Limiti Ernesto , Scucchia Lucio 
Published: July 2007

AbstractOptimum choice of bias point, load and drive level for solid‐state power amplifiers is performed via a design methodology based on a novel iterative analysis method. The effectiveness of the proposed methodology and the corresponding level of accuracy is demonstrated through a comparison with the results of a more elaborate commercial CAD software and with experimental data, © 1994 John Wiley & Sons, Inc.
An expansion function suited for fast full‐wave spectral domain analysis of microstrip discontinuities
Authors: Cicchetti Renato , Faraone Antonio 
Published: July 2007

AbstractA representation of the surface current density particularly suited for the electrodynamic characterization of arbitrarily shaped discontinuities in monolithic microwave and millimeter‐wave integrated circuits (MMICs) is presented. The spectral domain approach (SDA) is adopted to carry out the analysis. Some numerical results, obtained using the proposed current representation, are compared with those available in the literature. A fast and excellent numerical convergence for the scattering parameters is achieved.
Algorithms for the computer‐aided design of nonsynchronous, noncommensurate transmission‐line impedance transformers
Authors: Rosloniec Stanislaw 
Published: July 2007

AbstractThe new algorithms for design of nonsynchronous noncommensurate transmission‐line impedance transformers are presented. These algorithms make it possible to design the two‐, four‐, and six‐section transformers with the equal ripple insertion loss functions. The transformers designed in this way are significantly shorter in comparison to the corresponding well‐known quarter‐wave Chebyshev ones (synchronous commensurate). It is also shown that transformers of this type can be easily used as new prototype circuits for designing some other microwave devices. The 3‐dB three‐port power divider is described as an example of a device designed in this manner.
A rigorous design of millimeter‐waveguide devices using the 3d finite element method
Authors: Courivaud Nadine , Verdeyme Serge , Aubourg Michel , Guillon Pierre 
Published: July 2007

AbstractA rigorous filter design using the finite element method and an optimization process is described. To show the validity of this method, it is here applied to a millimeter‐wavelength metal insert filter. The influence of higher order mode interactions and of metallic losses is also described. © 1994 John Wiley & Sons, Inc.
Low‐noise gaas MESFET optimization using an orthogonal array approach
Authors: Miller Dain C. , Sadler Robert A. , Bahl Inder J. 
Published: July 2007

AbstractThis article presents an experimental optimization of the noise figure of small‐signal self‐aligned FETs. An L18orthogonal array has been used to find the main effects of specific device parameters on noise performance at 18 GHz. This knowledge has been used to find an alternative device which shows a ∼0.7‐dB improvement in noise measure without requiring major process changes. Hybrid low‐noise amplifiers built with the improved FETs confirm the noise performance and show record power performance for high dynamic range applications. © 1994 John Wiley & Sons, Inc.
Analysis of propagation on open microstrip lines using mixed‐order covariant projection vector finite elements
Authors: Crain Bruce R. , Peterson Andrew F. 
Published: July 2007

AbstractMany different procedures have been proposed for the finite element analysis of dielectric‐loaded waveguiding structures. However, most of these approaches are unreliable because of the appearance of spurious modes. Mixed‐order covariant projection finite elements have been shown to eliminate difficulties with spurious modes in vector waveguide formulations. The authors have developed a method to analyze open region dielectric‐loaded waveguiding problems using mixed‐order covariant projection finite elements. Details of the construction of the eigenvalue equation are presented. The treatment of open geometries using local absorbing boundary conditions is discussed. An efficient sparse eigensolver, based on iterative methods, that can solve the resulting nonlinear eigenvalue problem, is described. Analysis results are presented that demonstrate the ability of the formulation to solve for the propagating modes of open microstrip lines without the appearance of spurious modes.
Multipole‐accelerated capacitance computation for 3‐D structures in a stratified dielectric medium using a closed‐form Green's function
Authors: Jandhyala Vikram , Michielssen Eric , Mittra Raj 
Published: July 2007

AbstractIn this article, the capacitance matrices of three‐dimensional conducting structures embedded in a stratified dielectric medium are computed by using the fast muitipole method in conjunction with a closed‐form approximation of the appropriate Green's function. Image charges that result from the employment of this Green's function are incorporated into the fast multipole method. This technique is used to accelerate the iterative generalized minimal residual‐based solution of the system of equations generated by the method of moments. This yields the charge distributions on the conductors and thereby the required capacitance matrix. It is shown that the use of this technique typically results in a speedup of more than an order of magnitude over iterative and direct methods without a compromise of the numerical accuracy.
Specific applications of different modeling techniques for microwave package and structures design
Authors: Vilcot Anne , Ndagijimana Fabien , Cabon Béatrice 
Published: July 2007

AbstractDifferent simulation methods for analyzing microwave interconnects are presented. Dynamic and static as well as two‐dimensional (2D) or three‐dimensional (3D) methods are investigated, such as the method of moments (MoM), the SDM, and TLM method, in their specific domains of predilection. Results are finally compared together with those obtained from a commercial software product based on the FEM method. © 1995 John Wiley & Sons, Inc.
An electrothermal functional model of the microwave FET suitable for nonlinear simulation
Authors: Rizzoli Vittorio , Costanzo Alessandra , Lipparini Alessandro , Mastri Franco , Muzzarelli Giulio 
Published: July 2007

AbstractThis article introduces a CAD‐oriented functional model of the microwave FET depending on temperature as an additional state variable in addition to the usual gate and drain voltages. The model is fully conservative and non‐quasistatic, and thus considerably more advanced than other currently available empirical models. A novel parameter extraction strategy allows the simultaneous determination of the voltage and temperature dependence of the constitutive relations, making use of a set of DC measurements and bias‐dependent scattering matrices obtained at a single ambient temperature. The model can be coupled to a harmonic‐balance algorithm for the efficient electrothermal simulation of temperature‐dependent nonlinear microwave circuits, which the authors discussed in a previous article.
Nonlinear simulations in time domain methods
Authors: Mueller Ulf , Beyer Adalbert 
Published: July 2007

AbstractSince computer capabilities steadily increased during the past decades, time domain methods for the simulation of electromagnetic field behavior became more and more efficient in analyzing microwave and millimeter‐wave structures. They even enable the modeling of linear and nonlinear lumped devices embedded into a linear, passive, waveguiding environment. In this article, the principles of nonlinear modeling in the time domain using field simulation methods will be summarized and the applicability will be demonstrated for the TLM method.