bluuebunny/crossref_metadata_2025 huggingface dataset:
The Evolution of Bulk Solids Technology Since 1982
Authors: Feise H.J. , Carson J.W.
Published: February 2003

Since 1982 when Schwedes published his review paper on the “Evolution of Bulk Solids Technology since 1974” the field of bulk solids handling has experienced many advances. This paper attempts to review five major areas of technological development in this field. Three of these have been areas of constant interest since the days of Jenike’s pioneering work and were already part of Schwedes’ review: bulk solids characterization, modeling of the mechanical behavior of bulk solids, and standards for testing and silo loads. The two new areas of development are numerical simulations, namely FEM and DEM methods, and the technology of silo inserts. Developments in all these areas are indicative of the many significant accomplishments in the field of silo technology during the last twenty years. However, there are still many problems that need to be addressed and questions that need to be answered.
Flow Properties of Highly Dispersed Powders at Very Small Consolidation Stresses
Authors: Schulze D. , Wittmaier A.
Published: February 2003

With a modified standard ring shear tester yield loci of highly dispersed, dry powders were measured at preshear normal stresses down to 32 Pa and shear stresses down to 10 Pa. At small consolidation stresses stress, σ1, (< 500 Pa) the values obtained for the unconfined yield strength, σc, are proportional to the consolidation stress, σ1.
The Influence of Air Permeation on the Flow Properties of Bulk Solids
Authors: Klein J. , Höhne D. , Husemann K.
Published: February 2003

This paper considers the influence of low air permeation on the flow properties of slightly consolidated bulk solids in steady state flow. A ring shear device was built that enables the powder sample to be permeated during the shear test from below, upwards with flow velocities below the onset of fluidization. Furthermore, a mathematical model predicting the dependence of both the shear stress as well as the location of the shear zone in the shear cell on the aeration degree was developed. This model predicts a reduction of the shear stress with increasing air feed pressure and a sudden displacement of the shear zone from the cover to the bottom of the shear cell for a high degree of aeration. The good agreement between the measured results and the model predictions proves that the influence of the permeation on the flow properties of bulk solids can be traced back to the change of the normal stresses in the shear zone.
Measurements on Cohesive Powder with two Biaxial Shear Testers
Authors: Janssen R.J.M. , Zetzener H.
Published: February 2003

At the Technical University of Braunschweig (Germany) and the Delft University of Technology (The Netherlands) two True Biaxial Shear Testers were used to perform comparative measurements. The Braunschweig Biaxial Tester (BBT) and the Flexible Wall Biaxial Tester (FWBT) are part of a new generation of advanced powder testers whose goal is to fundamentally investigate powder flow based on the same principles. The general aim of these investigations is to compare the results obtained with both testers and gain new experience in handling powders.
Chute Performance and Design for Rapid Flow Conditions
Authors: Roberts A.W.
Published: February 2003

Many industrial chute applications are characterised by rapid flow conditions in which the bulk solid stream thickness or depth is less than the chute width. Under these conditions, it is possible to describe the stream flow by means of a lumped parameter model which takes into account the frictional drag around the chute boundaries as well as making allowance for inter‐particle friction. Equations of motion to describe the chute flow are presented and their application to the determination of chute profiles to achieve optimum flow is illustrated. By means of design examples, the problems associated with the feeding of bulk solids onto belt conveyors and conveyor transfers are discussed. Criteria for the selection of the most appropriate chute geometry to minimise chute wear and belt wear at the feed point are presented. The determination of optimum chute profiles to achieve specified performance criteria is outlined.
The Role of Particle Interactions on Suspension Rheology – Application to Submicron Grinding in Stirred Ball Mills
Authors: Stenger F. , Peukert W.
Published: February 2003

The superior performance of many products like paints, fillers, pigments, ceramics, or pharmaceuticals depends on the specific properties of nano‐particles. Special attention should be paid to models describing the influence of particle‐particle interactions. The experimental part of this contribution shows how rheological properties of milling suspensions change with milling time and suspension properties in the sub‐micron size range. Experimental results are related to theoretical models. The results demonstrate the key role that particle‐particle interactions play in altering the flow properties of milling suspensions throughout the process.
The Effects of Operating Conditions on the Milling of Microcrystalline Cellulose
Authors: Kwan C.C. , Ghadiri M. , Papadopoulos D.G. , Bentham A.C.
Published: February 2003

There is little detailed work relating the physical process that occurs during milling to the mechanical properties and mechanism of particle breakage. Very often, the selection of an appropriate mill and subsequently the determination of its optimum operating conditions are by trial and error. This paper look into optimizing the operating conditions of a ball mill through statistical analysis and the effect of temperature on the milling behavior of a common pharmaceutical excipient, microcrystalline cellulose (MCC). In addition, the bulk milling behavior of MCC is compared to its single particle breakage behavior. In this work, milling is conducted in a Retsch single ball mill where a bed of powder is subjected to impact by a steel ball in a horizontal cylindrical container. The container is vibrated horizontally at a set frequency, causing the ball to impact on the bed of particles. It is found that the finest MCC product can be achieved by milling a 2 g batch of material using a 12 mm ball size and at a frequency of 18 Hz. Temperature is found to have insignificant effect on the extent of breakage of MCC in both bulk milling and single particle impact testing. Milling and single particle impact experiments have both shown that MCC is more susceptible to breakage with increasing strain rate. In conclusion, the single impact tests could be used successfully for predicting the bulk milling behavior of the material, as shown in the case of MCC.
Comminution of Organic Material
Authors: Müller J.A.
Published: February 2003

The comminution of materials of bioorganic origin such as organic solids, biological agglomerates or micro‐organisms is described in this work. The intent of this disintegration process is to release products, to improve the product quality or to enhance biological degradation processes. Special analytical techniques based on biochemical parameters are required in order to characterize the result of the comminution of organic materials. These techniques supplement techniques that are known from the comminution of brittle inorganic materials. The defined stressing of single particles can be used to characterize the comminution properties of solid bioorganic materials. The disintegration of micro‐organisms has been investigated in the fields of biotechnological product release and biodegradability of wastewater sludges. It is possible to optimize the operational parameters of stirred ball mills based on stress intensity and stress number in order to reduce the energy input and to improve product release.
New Objectives of Sludge Treatment Considering a Safe Sludge Removal
Authors: Dichtl N.
Published: February 2003

Sewage sludge consists of valuable components such as nutrients as well as harmful substances, e.g. heavy metals. For sludge with a low concentration of pollutants, its utilization in agriculture is the best way of sludge reuse. Carbon recycling is also possible by using disintegration in combination with anaerobic degradation processes. The other important compound in sludge is phosphorus, which is a limited resource on earth. Recycling options for phosphorus are also described in the paper. A safe disposal of the residues can be achieved by using incineration.
Halide Anion Capture and Recognition by a Tetrahedral Tetraammonium Receptor in Water: A Molecular Dynamics Investigation
Authors: Chaumont Alain , Engler Etienne , Wipff Georges
Published: February 2003

We report molecular dynamics potential of mean force (PMF) simulations on the capture of halide anions X− (F−, Cl−, Br−) by a tetrahedral receptor L4+ built from four quaternary ammonium sites connected by six (CH2)n chains, leading to the formation of inclusion complexes X−⊂L4+. Simulations performed with a reaction field correction of the electrostatics and with PME‐Ewald summation gave very similar energy profiles. In aqueous solution, an energy barrier of 12‐17 kcal mol−1 was found for the three anions, mainly due to their dehydration when they enter through the largest triangular face of L4+. In the inclusion complexes, the anion is anchored near the center of the cavity due to the electrostatic field of the four positively charged ammonium sites, shielded from the surrounding water molecules. It was predicted that L4+ is selective for Cl− over Br− which both form stable inclusion complexes, while the F− complex should dissociate. The comparison of PMFs in aqueous solution and in the gas phase and the energy component analysis demonstrates the importance of solvent on the nature of these complexes and on the complexation energy profiles. The Cl−/Br− selectivity obtained from the dissociation pathways in water was in good agreement with the results of free energy perturbation simulations based on the “alchemical route” of a thermodynamic cycle, and consistent with experimental observations.
Topological Rotational Strengths as Chirality Descriptors for Fullerenes
Authors: Rassat André , Làszló Istvàn , Fowler Patrick W.
Published: February 2003

A graph‐theoretical procedure is proposed for assigning a chirality descriptor (the topological signτ(+) orτ(−)) to each enantiomer of a chiral polyhedron, polyhedral molecule or graph, independently of any vertex labelling scheme. Model Cartesian coordinates and rotational strengths are obtained using only adjacency information; a generalised HOMO–LUMO rotational strength is used to associate a sign with a Schlegel diagram and the corresponding three‐dimensional structure, polyhedron or molecule. The topological sign gives an unambiguous way of communicating the identity of an enantiomer. The mean‐square topological rotational strength is a possible measure of thechirality contentof a polyhedral graph or structure.
Synthesis of Enantiomerically‐Pure [13C]Aristeromycylcobalamin and Its Reactivity in Dioldehydratase, Glyceroldehydratase, Ethanolamine Ammonia‐Lyase and Methylmalonyl‐CoA Mutase Reactions
Authors: Weigl Ulrich , Heimberger Martin , Pierik Antonio J. , Rétey János
Published: February 2003

We describe a novel enantioselective synthesis of aristeromycin, the carbocyclic analogue of adenosine. The seven‐step synthesis is also suitable for the preparation of specifically‐labelled [6′‐13C]aristeromycin. Both the unlabelled and 13C‐labelled product was coupled to vitamin B12 to form aristeromycylcobalamin. This carbocyclic analogue of coenzyme B12 was examined for its coenzymic activity with several adenosylcobalamin‐dependent enzymes. For glyceroldehydratase and dioldehydratase, the reaction rate (kcat) was 38 and 44 % of that measured with adenosylcobalamin as coenzyme. In contrast, aristeromycylcobalamin showed no detectable activity with methylmalonyl‐CoA mutase and ethanolamine ammonia‐lyase. Instead, it was a weak inhibitor of the former and a strong inhibitor of the latter enzyme. The slower turnover rate with glyceroldehydratase raised the hope of detecting the 6′‐deoxyaristeromycyl radical intermediate. Comparison of the EPR spectra of the intermediates in the glyceroldehydratase reaction, which used adenosyl‐ and aristeromycylcobalamines, respectively, as coenzyme, revealed a significant shift and this suggests a different geometric position of these cofactors at the binding site during the cleavage of the carbon‐cobalt bond. However, we found no evidence for the existence of a 6′‐deoxyaristeromycyl radical during the reaction with [6′‐13C]aristeromycylcobalamin. We conclude that the lifetime of this radical is still too short to be observed.
A New Class of Ferromagnetically‐Coupled Mixed Valence Vanadium(IV/V) Polyoxometalates
Authors: Manos Manolis J. , Tasiopoulos Anastasios J. , Tolis Evangelos J. , Lalioti Nicolia , Woollins J. Derek , Slawin Alexandra M. Z. , Sigalas Michael P. , Kabanos Themistoklis A.
Published: February 2003

Reaction of [VVIOCl2(thf)2] with a bidentate nitrogen‐donor ligand (L: phen=1,10‐phenanthroline, 5‐mephen=5‐methyl‐1,10‐phenanthroline, bipy=2,2′‐bipyridine, 5,5′‐me2bipy=5,5′‐dimethyl‐2,2′‐bipy) in methyl alcohol, in the presence of triethylamine, leads to the formation of hexameric [V2IVV4V] oxo‐alkoxo‐vanadates of the general formula [V6O12(μ2‐OCH3)4(L)4]⋅x H2O [L=phen (1⋅4 H2O), 5‐mephen (2⋅6 H2O), bipy (3⋅4 H2O), 5,5′‐me2bipy (4⋅H2O)]. X‐ray structure analysis of 1⋅2 H2O and 4⋅8 CH3OH revealed a pair of V3O13N4 trimeric units sharing two corners, with a centrosymmetric planar V6‐core. In addition, a fully oxidized VV species [VV4O8(OCH3)2(μ3‐OCH3)2(5,5′‐me2bipy)2]⋅3 CH3OH (5⋅3 CH3OH) was isolated from the reaction mixture used for the synthesis of 4⋅H2O. The crystal structure of 5⋅3 CH3OH revealed a dicubane‐like framework with two missing vertices. Electron paramagnetic resonance (EPR) and variable temperature magnetic susceptibility studies for the hexamers 1⋅4 H2O and 3⋅4 H2O showed the complete localization of the single 3d electrons on the VIV ions and unusual ferromagnetic interaction between the two paramagnetic vanadium(IV) ions separated by a distance of about 5.1 Å. Furthermore, intermolecular antiferromagnetic interactions through π‐contacts of phenyl rings were observed for these species below 8 K. The ferromagnetic exchange coupling observed in the hexanuclear compounds 1⋅4 H2O and 3⋅4 H2O is also discussed using ab initio UHF calculations on a model compound. The value of the exchange coupling constant (3.7 cm−1) for this model compound, calculated using the broken symmetry approach, is in good agreement, both in sign and magnitude, with the experimental J values (6.00 cm−1 for 1⋅4 H2O and 8.54 cm−1 for 3⋅4 H2O).
Template Synthesis of Benzannulated N‐Heterocyclic Carbene Ligands
Authors: Hahn F. Ekkehardt , Langenhahn Volker , Meier Nicole , Lügger Thomas , Fehlhammer Wolf Peter
Published: February 2003

The reaction of 2‐azidophenyl isocyanide (7) with [M(CO)5(thf)] (M=Cr, W) yields the isocyanide complexes [M(CO)5(7)] (M=Cr 8, M=W 9). Complexes 8 and 9 react with tertiary phosphines such as triphenylphosphane at the azido function of the isocyanide ligand to give the 2‐triphenylphosphiniminophenyl isocyanide complexes 10 (M=Cr) and 11 (M=W). The polar triphenylphosphiniminophenyl function in complexes 10 and 11 can be hydrolyzed with H2O/HBr to afford triphenylphosphane oxide and the complexes containing the unstable 2‐aminophenyl isocyanide ligand. This ligand spontaneously cyclizes by intramolecular nucleophilic attack of the primary amine at the isocyanide carbon atom to yield the 2,3‐dihydro‐1H‐benzimidazol‐2‐ylidene complexes 12 (M=Cr) and 13 (M=W). Double deprotonation of the cyclic NH,NH‐carbene ligands in 12 and 13 with KOtBu and reaction with two equivalents of allyl bromide yields the N,N′‐dialkylated benzannulated N‐heterocyclic carbene complexes 14 (M=Cr) and 15 (M=W). The molecular structures of complexes 9 and 11–15 were confirmed by X‐ray diffraction studies.
An ab Initio/RRKM Study of Product Branching Ratios in the Photodissociation of Buta‐1,2‐ and ‐1,3‐dienes and But‐2‐yne at 193 nm
Authors: Lee Hwa‐Yu , Kislov Vadim V. , Lin Sheng‐Hsien , Mebel Alexander M. , Neumark Daniel M.
Published: February 2003

Ab initio G2M(MP2)//B3LYP/6‐311G** calculations have been performed to investigate the reaction mechanism of photodissociation of buta‐1,2‐ and ‐1,3‐dienes and but‐2‐yne after their internal conversion into the vibrationally hot ground electronic state. The detailed study of the potential‐energy surface was followed by microcanonical RRKM calculations of energy‐dependent rate constants for individual reaction steps (at 193 nm photoexcitation and under collision‐free conditions) and by solution of kinetic equations aimed at predicting the product branching ratios. For buta‐1,2‐diene, the major dissociation channels are found to be the single CC bond cleavage to form the methyl and propargyl radicals and loss of hydrogen atoms from various positions to produce the but‐2‐yn‐1‐yl (p1), buta‐1,2‐dien‐4‐yl (p2), and but‐1‐yn‐3‐yl (p3) isomers of C4H5. The calculated branching ratio of the CH3 + C3H3/C4H5 + H products, 87.9:5.9, is in a good agreement with the recent experimental value of 96:4 (ref. 21) taking into account that a significant amount of the C4H5 product undergoes secondary dissociation to C4H4 + H. The isomerization of buta‐1,2‐diene to buta‐1,3‐diene or but‐2‐yne appears to be slower than its one‐step decomposition and plays only a minor role. On the other hand, the buta‐1,3‐diene→buta‐1,2‐diene, buta‐1,3‐diene→but‐2‐yne, and buta‐1,3‐diene→cyclobutene rearrangements are significant in the dissociation of buta‐1,3‐diene, which is shown to be a more complex process. The major reaction products are still CH3 + C3H3, formed after the isomerization of buta‐1,3‐diene to buta‐1,2‐diene, but the contribution of the other radical channels, C4H5 + H and C2H3 + C2H3, as well as two molecular channels, C2H2 + C2H4 and C4H4 + H2, significantly increases. The overall calculated C4H5 + H/CH3 + C3H3/C2H3 + C2H3/C4H4 + H2/C2H2 + C2H4 branching ratio is 24.0:49.6:4.6:6.1:15.2, which agrees with the experimental value of 20:50:8:2:2022 within 5 % margins. For but‐2‐yne, the one‐step decomposition pathways, which include mostly H atom loss to produce p1 and, to a minor extent, molecular hydrogen elimination to yield methylethynylcarbene, play an approximately even role with that of the channels that involve the isomerization of but‐2‐yne to buta‐1,2‐ or ‐1,3‐dienes. p1 + H are the most important reaction products, with a branching ratio of 56.6 %, followed by CH3 + C3H3 (23.8 %). The overall C4H5 + H/CH3 + C3H3/C2H3 + C2H3/C4H4 + H2/C2H2 + C2H4 branching ratio is predicted as 62.0:23.8:2.5:5.7:5.6. Contrary to buta‐1,2‐ and ‐1,3‐dienes, photodissociation of but‐2‐yne is expected to produce more hydrogen atoms than methyl radicals. The isomerization mechanisms between various isomers of the C4H6 molecule including buta‐1,2‐ and ‐1,3‐dienes, but‐2‐yne, 1‐methylcyclopropene, dimethylvinylidene, and cyclobutene have been also characterized in detail.
Preorganized Bis‐Zinc Phosphodiester Cleavage Catalysts Possessing Natural Ligands: A Lesson Pertinent to Bimetallic Artificial Enzymes
Authors: Worm Karen , Chu Feiya , Matsumoto Kazunari , Best Michael D. , Lynch Vincent , Anslyn Eric V.
Published: February 2003

Two preorganized bis‐zinc receptors (2 and 3) were synthesized wherein the metals were ligated with ligands present in natural phosphodiesterases: imidazoles and carboxylates. The intrametallic distance is near 4.5 Å, that found in natural nucleases and other successful artificial nucleases. With only two imidazoles (2), the zinc binding affinities were not high enough to achieve cooperativity. Yet, with a third ligand, a carboxylate (3), cooperativity was found in the cleavage of HPNPP. The preorganization of 3 was achieved using a “steric gearing” strategy. The enhancement was 80‐fold for cooperation between the two metals relative to a mono‐metallic analogue (5). However, there was no observable enhancement in the hydrolysis of RNA using 3 relative to 5. Therefore, we conclude that placing two zinc atoms that are ligated with natural ligands at the appropriate distance for catalysis is not sufficient to enhance the cleavage of RNA, but is successful for activated RNA substrate mimics.
An Alternative Way of Characterising the Bonding in Compounds Featuring Main‐Group Elements and with the Potential for Multiple Bonding: On the Dissociation of Binary Main‐Group Hydrides
Authors: Himmel Hans‐Jörg , Schnöckel Hansgeorg
Published: February 2003

Herein the bonding in compounds featuring main‐group elements and with the potential for multiple bonding is studied theoretically by examination of their fragmentation into two fragments that still exhibit the same structure as they had in the molecule prior to dissociation. The fragments were calculated both in their electronic ground state and in an excited electronic state, in which the number of unpaired electrons is equal to the maximal number of bonds in the compounds before dissociation. The energies of the fragmentation processes (ΔEfrag) can be more directly linked to the bond strengths than the dissociation energies (ΔEdiss), because of the absence of any secondary effects like relaxation of the electronic state or of the geometry of the fragments. These relaxation energies of the fragments (ΔEfrag) are also studied herein. The energies derived in this work allow for an accurate comparison of the bonding properties in main‐group‐element hydrides. The trends of the fragmentation and relaxation energies are discussed in detail. It will be shown that the relaxation energies allow for a classification of the bonds (“classical” σ and π bonds or donor–acceptor interactions), while the fragmentation energies are good quantitative measures for the total bond strength. Similar calculations are on the way to explore the bonding in systems in which the hydrogen atoms are replaced by organic groups or halogen atoms.
Highly Enantioselective Conjugate Addition of AlMe3 to Linear Aliphatic Enones by a Designed Catalyst
Authors: Fraser Paul K. , Woodward Simon
Published: February 2003

2‐Hydroxy‐2′‐alkylthio‐1,1′‐binaphthyl compounds are catalytic promoters of the 1,4‐addition of AlMe3 to linear aliphatic enones in THF at −40 to −48 °C in the presence of [Cu(MeCN)4]BF4. At ligand loadings of 5–20 mol %, enantioselectivities of 80–93 % are realised for most substrates. To attain these values, the use of highly pure AlMe3 is mandatory. The presence of methylalumoxane (MAO), derived by hydrolysis, leads to reduced enantioselectivity and a conjugate addition product.
Recognition of Caffeine in Aqueous Solutions
Authors: Fiammengo Roberto , Crego‐Calama Mercedes , Timmerman Peter , Reinhoudt David N.
Published: February 2003

Binding of caffeine in aqueous solutions has been achieved for the first time by using water‐soluble, tetracationic peptide–porphyrin conjugates Zn‐1 as the receptor molecules. The association constant for caffeine with receptor Zn‐1 is in some cases as high as 6000 M−1, only 5–6 times lower than the highest binding constant reported for an artificial caffeine receptor in low polarity aprotic solvents. The binding mechanism has been studied by a combination of experimental techniques such as UV‐visible and NMR spectroscopy and microcalorimetry. Recognition of caffeine involves both stacking with the porphyrin ring and metal coordination. Subtle variations of the receptor structure affect the complexation. Receptors Zn‐1 have also been investigated for the recognition of molecules structurally related to caffeine, for example, 1‐methylimidazole. Selectivity towards oxopurine derivatives (caffeine and theophylline) have been found.
Unidirectional Threading of Triphenylureidocalix[6]arene‐Based Wheels: Oriented Pseudorotaxane Synthesis
Authors: Arduini Arturo , Calzavacca Francesco , Pochini Andrea , Secchi Andrea
Published: February 2003

Triphenylureidocalix[6]arenes 5 a,b are heteroditopic receptors having a pinched cone structure able to interact with both the cation and the anion of ion pairs. They are able to act as wheels and form complexes of the pseudorotaxane type with axles derived from dialkylviologen salts. An investigation into the possibility of exploiting the different structural and chemical information present on the two distinct rims of the calixarene wheel as control elements to pivot the direction of the axle threading processes and give access to oriented pseudorotaxanes is reported. It was verified that, in C6D6, an asymmetric dicationic axle derived from 4,4′‐bipyridil bearing two alkyl chains, one of which has a stopper, and triphenylureidocalix[6]arenes 5 a or 5 b form 1:1 supramolecular complexes belonging to the class of pseudorotaxanes. The structure of these complexes has been inferred through 1H NMR techniques. The data show that the axle accesses the calixarene cavity only through the wider rim. To further verify this issue, the new rotaxane 8, obtained by stoppering the pseudorotaxane derived from 5 b and the symmetrical axle 7 with diphenylacetyl chloride, was synthesised. In the 1H NMR spectrum of 8, the aliphatic protons of the axle portion that resides at the wide rim of the wheel show chemical shifts that are almost identical to those observed in pseudorotaxanes 6. On the other hand, those that stick out of the narrow rim of 8 experience chemical shifts that could not be found in the oriented pseudorotaxanes 6.
Molecular Switch Triggered by Solvent Polarity: Synthesis, Acid–Base Behavior, Alkali Metal Ion Complexation, and Crystal Structure
Authors: Ambrosi Gianluca , Dapporto Paolo , Formica Mauro , Fusi Vieri , Giorgi Luca , Guerri Annalisa , Micheloni Mauro , Paoli Paola , Pontellini Roberto , Rossi Patrizia
Published: February 2003

The synthesis and characterization of the new tetraazamacrocycle L, bearing two 1,1′‐bis(2‐phenol) groups as side‐arms, is reported. The basicity behavior and the binding properties of L toward alkali metal ions were determined by means of potentiometric measurements in ethanol/water 50:50 (v/v) solution (298.1±0.1 K,I=0.15 mol dm−3). The anionic H−1L−species can be obtained in strong alkaline solution, indicating that not all of the acidic protons of L can be removed under the experimental conditions used. This species behaves as a tetraprotic base (logK1=11.22, logK2=9.45, logK3=7.07, logK4=5.08), and binds alkali metal ions to form neutral [MH−1L] complexes with the following stability constants: logKLi=3.92, logKNa=3.54, logKK=3.29, logKCs=3.53. The arrangement of the acidic protons in the H−1L−species depends on the polarity of the solvents used, and at least one proton switches from the amine moiety to the aromatic part upon decreasing the polarity of the solvent. In this way two different binding areas, modulated by the polarity of solvents, are possible in L. One area is preferred by alkali metal ions in polar solvents, the second one is preferred in solvents with low polarity. Thus, the metal ion can switch from one location to the other in the ligand, modulated by the polarity of the environment. A strong hydrogen‐bonding network should preorganize the ligand for coordination, as confirmed by MD simulations. The crystal structure of the [Na(H−1L)]⋅CH3CN complex (space groupP21/c, a=12.805(1),b=20.205(3),c=14.170(2) Å,β=100.77(1)°,V=3601.6(8) Å3,Z=4,R=0.0430,wR2=0.1181), obtained using CH2Cl2/CH3CN as mixed solvent, supports this last aspect and shows one of the proposed binding areas.
Angiographic subsegmentectomy for the treatment of patients with small hepatocellular carcinoma
Authors: Iwamoto Shozo , Sanefuji Hayato , Okuda Kunio
Published: February 2003

BACKGROUND

The therapeutic results of nonsurgical treatment for patients with hepatocellular carcinoma (HCC) have been poor, and improved treatments are needed. The authors recently developed a new technique called angiographic subsegmentectomy for the treatment of patients with small HCC.

METHODS

The technique includes confirming the diagnosis of small HCC using a helical computed tomography (CT) scan combined with an angiography system for identifying the tumor‐feeding subsegmental hepatic artery, injecting lipiodol containing farmorubicin until it enters the portal vein in sufficient amounts, and injecting sponge particles into the hepatic artery for embolization. Occlusion of the hepatic artery with gel particles and occlusion of the portal vein by lipiodol induce infarction necrosis, which encompasses the entire tumor and the surrounding liver parenchyma.

RESULTS

The treatment was given to 23 patients with 30 HCC tumors that measured < 20 mm in greatest dimension. It was successful in all 23 patients. Serum alanine aminotransferase levels were elevated to a significant level in the majority of patients after treatment, mild ascites developed in three patients, and the patients complained of pain and fever posttreatment that were controlled readily. No patients developed hepatic failure. Only one patient developed recurrent disease posttreatment at 1.5 years, for a recurrence rate of 5% at 1 year and 6.6% at 1.5 years, a rate that has never been achieved with other treatment modalities.

CONCLUSIONS

Angiographic subsegmentectomy is a novel treatment for patients with small HCC. The results indicated that it is equivalent to undergoing small resection and is superior to conventional arterial chemoembolization. Cancer 2003;97:1051–6. © 2003 American Cancer Society.

DOI 10.1002/cncr.11106
Can older cancer patients tolerate chemotherapy?
Authors: Chen Hongbin , Cantor Alan , Meyer Julie , Beth Corcoran Mary , Grendys Edward , Cavanaugh Denise , Antonek Shirley , Camarata Angela , Haley William , Balducci Lodovico , Extermann Martine
Published: February 2003

BACKGROUND

To the authors' knowledge, few data currently are available regarding the tolerance to chemotherapy in older cancer patients. This prospective pilot study evaluated the changes in functional, mental, nutritional, and comorbid status, as well as the quality of life (QOL), in geriatric oncology patients receiving chemotherapy.

METHODS

Sixty patients age ≥ 70 years who were undergoing cancer chemotherapy were recruited in a university‐based comprehensive cancer center. Changes in physical function were measured by the Eastern Cooperative Oncology Group performance status (ECOG PS) and Instrumental Activities of Daily Living (IADLs), mental health changes were measured by the Mini‐Mental State Examination and the Geriatric Depression Scale (GDS), comorbidity was measured by Charlson's index and the Cumulative Illness Rating Scale‐Geriatric, nutrition was measured by the Mini‐Nutritional Assessment, and QOL was measured by the Functional Assessment of Cancer Therapy‐General (FACT‐G). Changes were assessed at baseline and at the end of treatment (EOT). Grade 4 hematologic and Grade 3–4 nonhematologic toxicities were recorded.

RESULTS

Thirty‐seven patients (63%) completed both assessments. Older cancer patients demonstrated a significant decline in measurements of physical function after receiving chemotherapy, as indicated by changes in scores on the IADL (P = 0.04) and on the physical (P = 0.01) and functional (P = 0.03) subscales of the FACT‐G. They also displayed worse scores on the GDS administered postchemotherapy (P < 0.01). Patients who experienced severe chemotoxicity had more significant declines in ECOG PS (P = 0.03), IADL (P = 0.03), and GDS (P = 0.04), and more gain in the social well‐being subscale (P = 0.02) of the FACT‐G, than those who did not experience severe chemotoxicity. However, changes in most scores were small in magnitude clinically. No significant change was found between baseline and EOT in nutrition, comorbidity, and other aspects of the FACT‐G.

CONCLUSIONS

Older cancer patients undergoing chemotherapy may experience toxicity but generally can tolerate it with limited impact on independence, comorbidity, and QOL levels. It is important to recognize and monitor these changes during geriatric oncology treatment. Cancer 2003;97:1107–14. © 2003 American Cancer Society.

DOI 10.1002/cncr.11110
Refractory Aspergillus pneumonia in patients with acute leukemia
Authors: Aliff Timothy B. , Maslak Peter G. , Jurcic Joseph G. , Heaney Mark L. , Cathcart Kathleen N. , Sepkowitz Kent A. , Weiss Mark A.
Published: February 2003

BACKGROUND

Pulmonary aspergillosis and other invasive fungal infections (IFIs) commonly complicate the management of patients with acute leukemia. Standard amphotericin‐based therapies may be ineffective for many patients and the available salvage agents (itraconazole and caspofungin) are reported to possess only moderate activity against resistant infections. Laboratory evidence suggests a synergistic interaction between amphotericin and caspofungin. The authors treated a group of patients with amphotericin‐refractory IFIs with the combination of caspofungin and amphotericin (or liposomal amphotericin).

METHODS

A retrospective evaluation of patients with amphotericin‐resistant IFIs was conducted. Diagnosis was based on clinical, radiographic, and when available, microbiologic data. Response to combination antifungal therapy was graded as either favorable or unfavorable. Favorable responses included improvement of both clinical and radiographic signs of fungal pneumonia. All other responses were graded as unfavorable.

RESULTS

Thirty patients were included in this analysis. Twenty‐six patients had acute leukemia. Based on recently published criteria, the IFIs were classified as proven in 6 patients, probable in 4 patients, and possible in 20 patients. The median duration and dose of amphotericin monotherapy were 12 days (range, 4–65 days) and 7.8 mg/kg (range, 4.2–66.1 mg/kg), respectively. The median duration of combination therapy was 24 days (range, 3–74 days). Eighteen patients (60%) experienced a favorable antifungal response. Twenty patients with acute leukemia received combination therapy for fungal pneumonias arising during intensive chemotherapy treatments. Favorable responses were observed in 15 of these patients (75%), and antifungal response did not depend on the response of the underlying leukemia. Survival to hospital discharge was significantly better (P < 0.001) in patients having a favorable response. Mild to moderate nephrotoxicity was noted in 50% of patients, necessitating the substitution of liposomal amphotericin. Mild elevation of alkaline phosphatase levels occurred in 30% of patients. Caspofungin was temporarily withheld from one patient who developed moderate but reversible biochemical hepatotoxicity.

CONCLUSIONS

The antifungal combination of caspofungin and amphotericin can be administered safely to high‐risk patients with hematologic malignancies. Although an absolute assessment of efficacy is limited by the design of this study, encouraging outcomes were noted for many patients. The authors plan to evaluate this regimen further in a randomized clinical trial. Cancer 2003;97:1025–32. © 2003 American Cancer Society.

DOI 10.1002/cncr.11115
Utilization of special education services and educational attainment among long‐term survivors of childhood cancer
Authors: Mitby Pauline A. , Robison Leslie L. , Whitton John A. , Zevon Michael A. , Gibbs Iris C. , Tersak Jean M. , Meadows Anna T. , Stovall Marilyn , Zeltzer Lonnie K. , Mertens Ann C.
Published: February 2003

BACKGROUND

The objective of the current report was to compare the self‐reported rates of special education (SE) and educational attainment among specific groups of childhood cancer survivors and a random sample of sibling controls.

METHODS

The Childhood Cancer Survivor Study is a retrospective cohort of individuals who were diagnosed with a cancer in childhood and survived at least 5 years postdiagnosis. This analysis includes 12,430 survivors and 3410 full siblings. Reported use of SE services and educational attainment were analyzed within subgroups defined by type of cancer, age at diagnosis, and type of treatment.

RESULTS

The use of SE services was reported in 23% of survivors and 8% of siblings, with the greatest differences observed among survivors who were diagnosed before age 6 years, most notably survivors of central nervous system (CNS) tumors (odds ratio [OR], 18.8; 95% confidence interval [95%CI], 15.01–23.49), leukemia (OR, 4.4; 95%CI, 3.75–5.16), and Hodgkin disease (OR, 4.4; 95%CI, 2.64–7.24). It was found that intrathecal methotrexate (IT MTX) and cranial radiation (CRT), administered alone or in combination, significantly increased the likelihood that a survivor would use SE (IT MTX only: OR, 1.3; 95%CI, 1.09–1.78; CRT only: OR, 7.2; 95%CI, 6.14–8.39; IT MTX and CRT combined: OR, 2.6; 95%CI, 2.30–2.95). A positive dose response was identified between higher doses of CRT and use of SE. It was determined that survivors of leukemia (OR, 1.6; 95%CI, 1.23–2.16), CNS tumors (OR, 2.7; 95%CI, 1.92–3.81), non‐Hodgkin lymphoma (OR, 1.8; 95%CI, 1.15–2.78), and neuroblastoma (OR, 1.7; 95%CI, 1.14–2.61) were significantly less likely to finish high school compared with siblings; however, when survivors received SE services, risk estimates approximated those of the sibling SE population.

CONCLUSIONS

Children who are diagnosed with cancer should be followed closely during and after treatment to identify early signs of learning disabilities and to maximize intervention strategies for the successful completion of scholastic goals. Cancer 2003;97:1115–26. © 2003 American Cancer Society.

DOI 10.1002/cncr.11117
Breast boost: Are we missing the target?
Authors: Benda Rashmi K. , Yasuda Gopika , Sethi Anil , Gabram Sheryl G.A. , Hinerman Russell W. , Mendenhall Nancy Price
Published: February 2003

BACKGROUND

Randomized trials have shown improved local control with the use of a breast boost for patients given breast‐conserving treatment for breast carcinoma. Although the use of a breast boost is routine practice, no standard technique has been established. The authors compared the commonly used clinical technique with a technique based on computed tomography (CT) imaging of surgical clips in the tumor bed.

METHODS

Thirty patients underwent CT simulation for postoperative radiation treatment planning as part of breast conservation therapy. During simulation, a CT‐compatible wire was placed on the patient's skin, outlining the intended electron boost field; an electron boost volume (EBV) was generated by contouring the tissue underlying the wire. Also contoured was a CT‐based clinical target volume (CTV) using surgical clips and postsurgical changes in the tumor bed as a guide. A planning target volume (PTV) was generated using a 1 cm margin around the CTV. An electron beam treatment plan was generated for each technique using the FOCUS three‐dimensional treatment planning system. Dose–volume histograms (DVH) were generated to determine the fraction of the PTV receiving 90% of the prescribed dose if treatment was delivered using the EBV. In addition, DVH analysis was done to determine the volume of normal tissue unnecessarily irradiated when using the EBV.

RESULTS

Although the electron cone size remained unchanged in most patients for both EBV and PTV, the isocenter differed more than 1 cm in the medial‐lateral direction in 5 patients and in the cephalocaudal direction in 12 patients. The en face gantry angle differed for most patients. On average, only 51% (range, 27–79%) of the PTV received 90% or more of the prescribed dose when the electron plan was generated using the EBV (P < 0.0001). Ten patients received the prescription dose to less than 50% of the PTV. Mean volume of normal tissue receiving more than 50% of prescribed dose was 64.5 cm3 (range, 24–119 cm3).

CONCLUSIONS

Clinical delineation of the tumor bed not only carries a significant risk of missing the target, but unnecessarily treats breast tissue that may otherwise be spared. Better delineation of the tumor bed, which optimizes coverage of the target volume and spares normal breast tissue, has the potential to improve both local control and cosmetic outcome. The authors recommend the use of surgical clips to delineate the target volume, followed by CT‐based treatment planning, accounting for not only microscopic disease, but also organ motion and daily setup error. Cancer 2003;97:905–9. © 2003 American Cancer Society.

DOI 10.1002/cncr.11142
Long‐term outcomes after treatment with external beam radiation therapy and palladium 103 for patients with higher risk prostate carcinoma
Authors: Dattoli Michael , Wallner Kent , True Lawrence , Cash Jennifer , Sorace Richard
Published: February 2003

BACKGROUND

The objective of this study was to define the long‐term prognostic significance of prostatic acid phosphatase (PAP) levels in patients with higher risk, early‐stage prostate carcinoma.

METHODS

One hundred sixty‐one consecutive patients with Stage T1–T3 prostate carcinoma (according to the 1992 criteria of the American Joint Committee on Cancer) were treated from 1992 through 1996. Each patient had a Gleason score ≥ 7 and/or a prostate specific antigen (PSA) level > 10 ng/mL. The original biopsy slides for 130 of 161 patients were retrieved and rereviewed by a single pathologist (L.T.). Enzymatic PAP measurements were determined using a standard method. Values up to 2.5 Units were considered normal. Patients received 41 grays (Gy) of external beam radiation therapy to a limited pelvic field followed 4 weeks later by a palladium 103 (Pd‐103) boost using transrectal ultrasound and fluoroscopic guidance as described previously. The prescribed minimum Pd‐103 dose to the prostate was 80 Gy (pre‐National Institute of Standards and Technology [NIST]‐99). Freedom from biochemical failure was defined as a serum PSA level ≤0.2 ng/mL at last follow‐up.

RESULTS

There was little correlation between pretreatment PSA levels, Gleason scores, and PAP measurements. Thirty‐eight patients developed biochemical failure. The overall actuarial freedom from biochemical progression at 10 years is 79%, with 118 patients followed for > 5 years. In a multivariate Cox proportional hazards analysis that considered each factor as a continuous variable, the strongest predictor of failure was PAP (P = 0.0001), followed by Gleason score (P = 0.13), and PSA (P = 0.04). PAP was especially helpful in stratifying patients with pretreatment PSA levels between 4 ng/mL and 20 ng/mL, for whom the prognosis does not different when they are subdivided into PSA categories. When the PAP subgroup analysis was limited to this relatively favorable group, there was a wide range of prognoses.

CONCLUSIONS

The biochemical cure rate was remarkably high among the 161 patients evaluated. The fact that the PAP was the strongest predictor of long‐term biochemical failure in patients with otherwise higher risk features reported here suggests that it may be a more accurate indicator of micrometastatic disease compared with the Gleason score and the PSA level. This report adds to the rationale for reintroducing PAP measurement into general practice. Cancer 2003;97:979–83. © 2003 American Cancer Society.

DOI 10.1002/cncr.11154
Characterization of laryngopharyngeal reflux in patients with premalignant or early carcinomas of the larynx
Authors: Lewin Jan S. , Gillenwater Ann M. , Garrett J. David , Bishop‐Leone Julie K. , Nguyen Dominic D. , Callender David L. , Ayers Gregory D. , Myers Jeffrey N.
Published: February 2003

BACKGROUND

An association between laryngopharyngeal reflux (LPR) and laryngeal carcinoma has been suggested, but remains unproven. The current pilot study was performed to determine the incidence of LPR among patients with early laryngeal carcinomas or dysplasia and to examine the associations between levels of LPR and histologic stage, smoking status, the symptom of heartburn, and body position during reflux episodes.

METHODS

Behavioral and 24 hour pH monitoring data were prospectively acquired and analyzed for 40 previously untreated adults with dysplasia, T1or T2 laryngeal carcinomas.

RESULTS

Eighty‐five percent of patients had LPR. No significant association was shown between the level of LPR and histologic stage or smoking status. Heartburn did not predict LPR. The incidence of LPR in the upright body position was 91%, compared with 9% in the supine position, among patients with LPR.

CONCLUSIONS

When compared to available normative data, the current findings show a high incidence of LPR in patients with premalignant and early laryngeal cancer. These findings highlight the need for a matched‐control study evaluating LPR as a potential predisposing factor for laryngeal carcinoma. Cancer 2003;97:1010–4. © 2003 American Cancer Society.

DOI 10.1002/cncr.11158
Combination chemotherapy for desmoid tumors
Authors: Okuno Scott H. , Edmonson John H.
Published: February 2003

BACKGROUND

Desmoid tumor (aggressive fibromatosis) is an aggressive fibroblastic proliferation of well circumscribed, locally invasive, differentiated fibrous tissue. For patients with desmoid tumors that are not amenable to surgery or radiation therapy, the use of hormonal agents and nonsteroidal antiinflammatory drugs (NSAIDs) have been attempted, with some success. The use of chemotherapy also has been reported to have activity.

METHODS

Seven patients (5 males and 2 females) with a median age of 40 years (range, 17–66 years) who received cytotoxic chemotherapy (combinations of cyclophosphamide and doxorubicin; mitomycin, doxorubicin, and cisplatin; and ifosfamide and etoposide) for desmoid tumor were reviewed retrospectively. Five patients were found to have recurrent tumors. Four patients had familial adenomatous polyposis. Four patients had failed tamoxifen and six had failed NSAIDs prior to receiving cytotoxic chemotherapy. In six patients the desmoid tumor was intraabdominal and one tumor had occurred on the buttock.

RESULTS

Patients received a median number of six cycles of chemotherapy (range, two to eight cycles). Objective disease regression occurred in 3 patients. There was an apparent clinical benefit in six patients with the duration of benefit ranging from 3 months to 15 years. The chemotherapy was well tolerated and no treatment‐related mortality was reported.

CONCLUSIONS

The results of the current study indicate that the use of combination chemotherapy for desmoid tumors may provide long‐term clinical benefits. Cancer 2003;97:1134–35. © 2003 American Cancer Society.

DOI 10.1002/cncr.11189