bluuebunny/crossref_metadata_2025_split huggingface dataset:
In‐Process Particle Size Distribution Measurements and Control
Authors: Harvill Thomas L. , Hoog Jared H. , Holve Donald J. 
Published: May 2005

AbstractIn‐process measurement of particle size and concentration distributions provides continuous analysis, quality control, and optimization of product yield. As process production rates continue to improve, the delay between laboratory analysis and process correction of the product stream becomes more significant and costly in many commercial applications. Elimination of sample handling and operator manipulation is now possible for most pneumatic flows using optical methods which are properly interfaced with the process stream. Insitec has developed such an instrument based on ensemble laser‐diffraction that has been successfully applied to a wide range of research and industrial process applications.As part of the adaptation of instrumentation to the specific needs of different process applications, we have developed several different interface arrangements, including a direct inline system and an eductor bypass instrument. A specific window purge design has been developed and shown to operate for extended time periods (exceeding one month and more) without maintenance. To address the wide range of operating concentrations that occur in practice, a variable pathlength interface has been developed along with a deconvolution algorithm that corrects multiple scattering effects for light transmissions down to 20%. Distribution update rates are computed and displayed in less than 5 seconds. This methodology is described along with measurements in a non‐steady pharmaceutical powder processing application. Results show uniform size measurement for ten‐fold concentration variations. Real time measurements allowed diagnosis and correction of non‐steady feed rates to a classifier‐mill.
Morphological Characterization of Flowing Particles by Image Analysis Techniques
Authors: Bonifazi Giuseppe , Francini Franco , Guarnieri Vanni , Longobardi Giuseppe , Massacci Paolo , Recinella Marco 
Published: May 2005

AbstractThe guidelines which are at the base of the definition of a system capable of operating on a slurry containing the solid particulate for its characterization are described. All the considerations have been developed with particular reference to the case of a granular heterogeneous material in particular, the different research problems, making a comparison with the case of static images, acquired under laboratory conditions, are pointed out. Attention was focused on problems of acquisition and digital image processing to obtain information which is clean from noise and errors. The considerations and procedures analysed show general validity and can be applied to a large number of problems linked to the “on‐line” morphological characterization of particulate solids materials. Some results for morphological characteristics of lead sulphide (PbS) samples are reported.
Influence of the Measurement Volume on the Phase Error in Phase Doppler Anemometry. Part 2: Analysis by extension of geometrical optics to the laser beam; Refractive mode operation
Authors: Albrecht Heinz‐E. , Wenzel Marcus , Borys Michael 
Published: May 2005

AbstractThe influence of the measurement volume can be investigated by using extended geometrical optics, which is based on geometrical optics by including the amplitude and phase distribution in the laser beam. The dynamics in phase Doppler anemometry can be analysed, in addition to effects of the particle size‐dependent detection volume. Extended geometrical optics has been developed as a powerful tool to investigate these influences for each order of light scattering separately. Phase errors caused by Gaussian‐beam intensity distribution and the curvature of the wave fronts beyond the beam waist can easily be calculated. According to Part 1 (Reflective Mode Operation), the influence of the particle trajectories on measured phase and mass concentration is simulated for refractive mode operation.
Characterisation of Particle Size for Polydisperse Powders aerosolised and detected by light scattering
Authors: Sato Shintaro , Pui David Y. H. , Vincent James H. 
Published: May 2005

AbstractThis paper describes a study to determine the most appropriate particle size parameter for polydisperse powders dispersed as aerosol and detected by light scattering. It is relevant to many areas of engineering research. By means of calculations of the intensity of light scattered from particles of different sizes, it has been shown that the surface median aerodynamic diameter (SMAD) is an appropriate measure for polydisperse aerosolised powders. The microscope‐based procedure for obtaining the SMAD is described, as well as its implementation for narrowly‐graded polydisperse powders of fused alumina of type which have been widely used in studies of particle transport in wind tunnels. It was shown that for the fused alumina powders examined, SMAD = 1.25 x (PASMAD), where PASMAD is the projected area surface median aerodynamic diameter.
Coal Handleability — A good or a bad coal?
Authors: Brown Gareth J. , Creasey Des S. , Miles Nick J. 
Published: May 2005

AbstractThe avalanching behaviour of two coal types was determined, one of good and the other of poor handleability characteristics. This revealed significant differences in the nature of flow of the coals. Analysis of the strange attractors of the weight series of avalanches enabled quanitification of this difference, and the establishment of practical, relative criteria for the measurement of coal handleability. These criteria will now enable a structured study of the variables that affect handleability, for example proportion of fines and moisture content, and industrial consumers of coal to specify minimum acceptable limits for its transport characteristics.
Stilbene and Azobenzene Diazonium Compounds as dye reagents for crown ethers
Authors: Walkow Fred , Israel Gunther 
Published: May 2005

AbstractThe change of light absorption of six coloured diazonium compounds (1, 2a, 2b, 3, 4, 5) on complexation with five 18‐crown‐6 derivatives (6–10) in 1,2‐dichloroethane was investigated. In the benzene, stilbene and azobenzene series complexation produces only hypsochromic shifts of the intramolecular ct‐band of the diazonium ions up to 140 nm. The extend of the shift is effected by ion pairing. The ct‐transition energy of the complexes diazonium ion is independent on the present anion in contrast to the uncomplexed compounds. The colour changes are not caused by host to guest charge transfer or E/Z‐isomerisation of the stilbene and azobenzene derivatives. A quantitative explanation of the colour changes is given basing on an electrostatic interaction model.
5‐Aminothiazole aus Dithioestern und α‐Aminoacetonitril
Authors: Thiel W. 
Published: May 2005

5‐Aminothiazoles from Dithiocarboxylic Esters and α‐AminoacetonitrileCarbamoyldithiocarboxylicesters 1 and heteroaryldithiocarboxylic esters 2 react with α‐aminoacetonitriles under mild conditions to form 2‐carbamoyl‐5‐aminothiazoles 5 or 2‐heteroaryl‐5‐aminothiazoles 6. The intermediate N‐cyanomethylthiooxamides 3 can be isolated. The 2‐heteroaryl‐5‐aminothiazoles 6 and their acyl derivatives 7 are highly fluorescent, in contrast to the azomethines 8 derived from 6.
Aromaticity as a Quantitative Concept. 4. Less familiar five‐ and six‐membered monocyclic heterocycles
Authors: Katritzky Alan R. , Barczynski Piotr 
Published: May 2005

AbstractAn additional set of 23 monoheterocycles was subjected to AM1 calculations, and the characteristics thus determined, together with available experimental data, treated by PC analysis. Utilizing characteristic loadings previously determined for other monoheterocycles, scores for the 23 monoheterocycles were deduced. The new scores correlate well with those previously found, and with the chemical nature of the heterocycles. The dominant influence on the t1 is the nature of the hetero atoms present, whereas the dominant influence on t2 is the number of hetero atoms present. It is concluded that pyridine‐like nitrogen atoms have relatively little effect on clasical aromaticity: five‐membered rings are less aromatic than six‐membered, the presence of an oxygen atom has a particularly aromaticity‐reducing effect, whereas the effect of sulfur is much less than oxygen and only a little more than nitrogen. The predictive power for the present compounds is limited by the relative paucity of and some problems with the input data but suceeds well for Ix′, ΔN and ΔHf.
Crystalline Sodium Selenocarboxylates – synthesis and characterization
Authors: Kato Shinzi , Kageyama Hideki , Takagi Kazutaka , Mizoguchi Kazuaki , Murai Toshiaki 
Published: May 2005

AbstractA series of sodium selenocarboxylates 2 were isolated from the reaction of diacyl selenides with sodium ethanolate and characterized. A convenient preparation of the sodium salts 2 by the direct reaction of acyl chlorides with sodium selenide was also established. The salts are colourless to slightly pale yellow crystals and labile towards moisture. They readily react with alkyl iodides at room temperature to give the corresponding Se‐alkyl esters 3.
Donorsubstituierte 2,4‐Diazacyclopentadienone und indigoide 1,3,5,7‐Tetraazafulvalene
Authors: Glas G. , Gompper Rudolf , Junius M. , Mertz R. , Wagner H.‐U. , Nöth Heinrich , Staudigl M. 
Published: May 2005

Donor Substituted 2,4‐Diazacyclopentadienones and Indigoid 1,3,5,7‐TetraazafulvalenesHydrolysis of tris(diethylamino)imidazolylium chloride gives rise to 2,5‐bis‐diethyl‐amino‐4H‐imidazolin‐4‐one; thiolysis leads, depending on conditions, to 2,5‐bis‐diethylamino‐4H‐imidazolin‐4‐thione or potassium 2,6‐bis‐diethylamino‐1,3,5,7‐tetraazafulvalene‐4,8‐dithiolate. The latter can be protonated to form green 2,6‐bis(dimethylamino)‐3,4,7,8‐tetrahydro‐1,3,5,7‐tetraaza‐fulvalen‐4,8‐dithione, a new indigoid compound, and alkylated to give blue 2,6‐bis‐diethylamino‐4,8‐bis‐alkylthio‐1,3,5,7‐tetraazafulvalenes. Treatment of 2,5‐bis‐diethylamino‐4H‐imidazolin‐4‐thione with copper furnishes 2,6,4,8‐tetrakis‐diethylamino‐1,3,5,7‐tetraazafulvalene. – Oxidation of 2,6‐bis‐dimethylamino‐3,4,7,8‐tetrahydro‐1,3,5,7‐tetraazafulvalen‐4,8‐dithione gives rise to (2,2′‐bis‐diethylamino‐4,4′‐bi(4H‐imidazol)‐5,5′‐dithione, corresponding to dehydroindigo, and reduction leads to a colorless compound, corresponding to leucoindigo.
α‐substituierte Phosphonate. 56. Synthese und Reaktionen von 1‐Formylamino‐2,2,2‐trichlorethanphosphonaten
Authors: Scheidecker S. , Köckritz A. , Schnell M. 
Published: May 2005

α‐substituted Phosphonates. 56. Synthesis and Reactions of 1‐Formylamino‐2,2,2‐trichloroethanephosphonatesThe chemical behaviour of formylamino phosphonates 2, prepared from 1,2,2,2‐tetrachloroethylformamid and trialkylphosphites, was investigated. The phosphonate 2b was cleaved under acidic conditions to aminosubstituted phosphonate 3. The phosphonates 2 and 3 react with bases to 2,2‐dichlorovinylphosphonates 8 and 6, respectively. Oxazoles 9 are formed by treatment of the phosphonate 2 and 8, respectively, with prim. or sec. amines.
Tetrazolverbindungen. 5. Synthese und Umaminierung von Enaminoketonen der Tetrazolreihe
Authors: Fischer G. W. 
Published: May 2005

Tetrazole Compounds. 5. Synthesis and Transamination of Enamino Ketones of the Tetrazole SeriesTetrazole‐5‐acetaldehyde enamines 5 react with aliphatic and aromatic carboxylic acid chlorides in the presence of an auxiliary base (e.g. pyridine or triethylamine) to give tetrazolylsubstituted enamino ketones 6. The latter can be modified by acid‐catalyzed transamination with secondary aliphatic amines (e.g. diethylamine, pyrrolidine, piperidine, morpholine, hexamethylene imine) yielding 5‐(1‐acyl‐2‐dialkylamino‐vinyl)‐1‐aryl‐1 H‐tetrazoles 7. The analogue transamination of 6 with primary alkyl, aralkyl, and aryl amines results in corresponding secondary enamino ketones 8, which exist in solution as an equilibrium mixture of the Z and E form. Acylation of secondary tetrazole‐5‐acetaldehyde enamines 9 does not lead to 8, but to the isomeric N‐acyl derivatives 10. – Characteristic 1H‐n.m.r., u.v., and i.r. spectroscopic data of the novel products are reported.
4‐Anilino‐5,7‐dinitrobenzofurazan – Untersuchungen zur Struktur und Reaktivität
Authors: Niclas H.‐J. , Göhrmann B. , Ramm M. , Schulz B. 
Published: May 2005

4‐Anilino‐5,7‐dinitrobenzofurazan – Studies on Structure and Reactivity4‐Anilino‐5,7‐dinitrobenzofurazan3reacts with gaseous ammonia at room temperature under elimination of aniline leading to4. Compound3may also be transformed into the isolable salt6by treatment with aqueous KHCO3, whereas4reacts with KHCO3furnishing potassium 5, 7‐dinitrobenzofurazan‐4‐olat5. As shown by X‐ray analysis and CNDO/2 calculations of3, the case with which the nucleophilic substitutions proceed may be explained by the assumption of an azomethine structure in4and6.
Photoinitiierte Polymerisation mit Dialkoxythiocarbonyldisulfiden – eine Polymerisationsreaktion mit Primärradikalabbruch
Authors: Timpe Hans‐Joachim , Ali Salah , Ulrich Sven , Müller Gerd , Kronfeld Klaus‐Peter , Zubarev V. E. 
Published: May 2005

Photoinitiated Polymerization with Dialkoxy Thiocarbonyl Disulfides – a Polymerization Reaction with Primary Radical TerminationThe photoinduced free radical polymerization of methyl methacrylate (MMA) and some other vinyl monomers using dialkoxy thiocarbonyl disulfides (1–4) as photoinitiators was studied. The photolysis of these initiators leads to cleavage of the SS bond, which was determined by spin trapping experiments with phenyl tert‐butyl nitrone. No evidence was found for a further thermal decomposition of the primary alkoxy thiocarbonyl sulfide radicals (R·) at room temperature. In the absence of scavengers the primary radicals react back exclusively to the initial compounds, due to a strong cage effect. By means of UV spectroscopic measurements and in the presence of MMA the quantum yields of the initiator decomposition were detected to be 0.8. The polymerization of acrylic and methacrylic derivatives can be initiated by the R·, contrary to the situation with fumarates and maleates. The mechanism of MMA polymerization depends on the light intensity absorbed by the initiators. At high intensities the combination of primary and polymer radicals terminates the chain reaction. This follows from the measured monomer exponent of α = 2, the light intensity exponent of β = 0,2 and the number of thiocarbonyl end groups of 2 in the polymers isolated. Contrary to this, in the low intensity region the experimental data obey the ideal kinetic equation. Kinetic modelling gives evidence for an interaction of the monomer with the cage radicals.
Vergleichende Untersuchungen zur Arylaminierung von Benzofuroxan‐Derivaten
Authors: Göhrmann B. , Niclas H.‐J. 
Published: May 2005

Comparative Studies on Arylamination of Benzofuroxan DerivativesThe amination of benzofuroxan 2a and monosubstituted benzofuroxans 2b–e with alkali metal salts of formanilides 1 and sodium acetanilides 6 is described. Thus, the reaction of 2a with 6a–d gives the benzotriazole 1‐oxides 3a–d. The benzofuroxans 2b and 2c react with sodium formanilides to give the isomeric mixtures 3f/3g and 3h/3i. Potassium 4‐nitroformanilide reduces 2a furnishing benzofurazan 7. Nitrobubstituted benzofuroxans such as 2d and 2e undergo a carbocyclic amination leading to the benzofurazans 8 and 9.
Hydrierung von Crotonaldehyd und Acetaldol mit modifizierten Pd‐Trägerkatalysatoren. II. Zum Einfluß einer Chromiummodifizierung auf Pd Al2O3‐Katalysatoren
Authors: Bohm D. , Kripylo P. , Stobbe J. 
Published: May 2005

Hydrogenation of Crotonaldehyde and Acetaldol with Modified Pd‐Supported Catalysts. II. On the Influence of a Chromium Modification of Pd/Al2O3 CatalystsThe catalytic properties in hydrogenation reactions on chromium containing Pd/Al2O3 catalysts are influenced by an “esemble effect.” The specific activity in the hydrogenation of crotonaldehyde to n‐butyraldehyde is independent of the chromium content in the Pd/Al2O3 catalysts. But the specific activity for the hydrogenolysis of ethane is decresed with the chromium content of the catalysts. On the other hand, was observed that the specific activity of the conversion of acetaldol to n‐butyraldehyde rises with increasing chromium content. This specific activity is higher than the specific hydrogenation activity.This fact can be considered as an argument for an asynchron hydrogenolysis of the hydroxyl group in the formation of n‐butyraldehyde from acetaldol on PdCr/Al2O3 catalysts.
Protein fluorescence quenching by small molecules: Protein penetration versus solvent exposure
Authors: Calhoun Dorothy B. , Vanderkooi Jane M. , Holtom Gary R. , Englander S. Walter 
Published: May 2005

AbstractExperiments were done to test the thesis that acrylamide and similar small molecules can penetrate into proteins on a nanosecond time scale. The approach taken was to measure the pattern of fluorescence quenching exhibited by quenching molecules differing in molecular character (size, polarity, charge) when these are directed against protein tryptophans that cover the whole range of tryptophan accesibility. If quenching involves protein penetration and internal quencher migration, one expects that larger quenchers and more polar quenchers should display lesser quenching. In fact, no significant dependence on quencher character was found. For proteins that display measurable quenching, the disparate quenchers studied display very similar quenching rate constants when directed against any particular protein tryptophan. For several proteins having tryptophans known to be buried, no quenching occurs. These results are not consistent with the view that the kinds of small molecules studied can quite generally penetrate into and diffuse about within proteins at near‐diffusion‐limited rates. Rather the results suggest that when quenching is observed, the pathway involves encounters with tryptophans that are partially exposed at the protein surface. Available crystallographic results support this conclusion.
Translational repression in vitro by the bacteriophage T4 regA protein
Authors: Adari Hedy Y. , Spicer Eleanor K. 
Published: May 2005

AbstractThe bacteriophage T4 translational represor regA protein has been purified from an overproducing strain, and its activity has been studied in simple in vitro protein synthesis reactions. RegA protein was found to inhibit the translation of T4 genes 44, 45, and ORF45‐1 in a concentration‐dependent fashion. Expression of two other T4 genes which are insensitive to regA protein in vivo, genes 32 and 43, was unaffected by the presence of regA protein. Specific inhibition of synthesis of genes 44, 45, and ORF 45‐1 proteins was achieved with 5–20 μM concentrations of regA protein, without the addition of any other T4 encoded proteins or cofactors. When in vitro protein synthesis was performed in two steps, uncoupling translation from transcription, regA protein had an inhibitory effect regardless of whether it was added at the initiation of transcription or only at the translation step. This indicates that regA protein functions during the translation step of protein synthesis in vitro in agreement with previous in vivo studies of regA protein.
Cloning, expression, and nucleotide sequence of livR, the repressor for high‐affinity branched‐chain amino acid transport in Escherichia coli
Authors: Antonucci Tammy K. , Wagner Lois M. , Oxender Dale L. 
Published: May 2005

AbstractThe livR gene encoding the repressor for high‐affinity branched‐chain amino acid transport in Escherichia coli has been cloned from a library prepared from the episome F106. The inserted DNA fragment from the initial cloned plasmid, pANT1, complemented two independent, spontaneously derived, regulatory mutations. Subcloning as well as the creation of deletions with Bal31 exonuclease revealed that the entire regulatory region is contained within a 1.1‐kb RsaI‐SalI fragment. Expression of the pANT plasmids in E. coli minicells showed that the regulatory region encodes one detectable protein with an apparent molecular weight of 21,000. DNA sequencing revealed one open reading frame of 501 bp encoding a protein with a calculated MW of 19,155. The potential secondary structure of the regulatory protein has been predicted and it suggests that the carboxy terminus may fold into three consecutive alpha helices. These results suggests that the livR gene encodes a repressor which plays a role in the regulation of expression of the livJ and the livK transport genes.
Activation of retinal rod cyclic GMP‐phosphodiesterase by transducin: Characterization of the complex formed by phosphodiesterase inhibitor and transducin α‐subunit
Authors: Deterre Philippe , Bigay Joëlle , Robert Mylène , Pfister Claude , Kühn Herman , Chabre Marc 
Published: May 2005

AbstractThe GTP‐binding subunit of transducin (Tα) activates the cGMP phosphodiesterase (PDE) of bovine retinal rods by relieving the constraint imposed by the inhibitory subunit PDEγ. We have isolated and characterized the complex Tα.GTPγS‐PDEγ formed when Tα is activated by the nonhydrolyzable analog GTPγS. Sedimentation and light‐scattering techniques demonstrate that, in contrast to free Tγ.GTPγS, which is soluble, the Tα.GTPγS‐PDEγ complex, as well as Tα.GTP‐PDEγ, is membrane bound at cytosolic ionic strength. It is eluted from the membrane at low ionic strength as a monomeric and 1:1 stoichiometric complex. The relative affinities of PDEγ for PDEαβ and for Tα.GTP are discussed.
A very short peptide makes a voltage‐dependent ion channel: The critical length of the channel domain of colicin E1
Authors: Liu Q. R. , Crozel V. , Levinthal F. , Slatin S. , Finkelstein A. , Levinthal C. 
Published: May 2005

AbstractCleavage of colicin E1 molecules with a variety of proteases or with cyanogen bromide (CNBr) generates COOH‐terminal fragments which have channel‐forming activity similar to that of intact colicin in planar lipid bilayer membranes. The smallest channel‐forming fragment obtained by CNBr cleavage of the wild‐type molecule consists of the C‐terminal 152 amino acids. By the use of oligonucleotide‐directed mutagenesis, we have made nine mutants along this 152 amino acid peptide, in which an amino acid was replaced by methionine in order to create a new CNBr cleavage site. The smallest of the CNBr‐cleaved C‐terminal fragments with channel‐forming activity, in planar bilayer membranes, was generated by cleavage at new Met position 428 and has 94 amino acids, whereas a 75 amino acid peptide produced by cleavage of a new Met at position 447 did not have channel activity. The NH2‐terminus of the channel‐forming domain of colicin E1 appears therfore to lie between residues 428 and 447. Since, however, the last six C‐terminal residues of the colicin can be removed without changing activity, the number of amino acids necessary to form the channel is 88 or less. In addition, the unique Cys residue in colicin E1 was replaced by Gly, and nine mutants were then made with Cys placed at sequential locations along the peptide for eventual use as sulfhydryl attachment sites to determine the local environment of the replaced amino acid. In the course of making 21 mutants, eight charged residues have been replaced by uncharged Met or Cys without changing the biological activity of the intact molecule.It has been proposed previously that the conformation of the colicin E1 channel is a barrel formed from five or six α‐helices, each having 20 amino acids spanning the membrane and two to four residues making the turn at the boundary of the membrane. Our finding that 88 amino acids can make an active channel, combined with recently reported stoichiometric evidence that the channel is a monomer excludes this model and adds significant constraints which can be used in building a molecular model of the channel.