bluuebunny/crossref_metadata_2025 huggingface dataset:
Ultrasonography and hormone profiles of adrenocorticotrophic hormone (ACTH)-induced persistent ovarian follicles (cysts) in cattle
Authors: Dobson H , Ribadu AY , Noble KM , Tebble JE , Ward WR
Published: January 2004

The objective of this study was to develop a model for the study of abnormal ovarian follicles in cattle by treating heifers with adrenocorticotrophic hormone (ACTH) (100 iu at 12 h intervals for 7 days, beginning on day 15 of the oestrous cycle). Cortisol concentrations increased (P < 0.05) within 24 h after beginning ACTH treatment and cortisol and progesterone concentrations remained elevated after cessation of ACTH treatment for 8 and 4 days, respectively. The pulses and surges of LH decreased during ACTH treatment, but FSH profiles were similar to those in controls and persistent or prolonged follicles were eventually observed in all heifers. In five heifers, prolonged dominant follicles ovulated after 10 days, whereas in six heifers, persistent follicular structures were present for 20 days, but ceased to secrete oestradiol after approximately 12 days. In the heifers with persistent follicular structures, new follicles emerged when the persistent follicle became non-oestrogenic. During the last 2 days of normal follicular growth, the concentration of oestradiol was greater than it was during prolonged or persistent follicle development (P < 0.05). There were no differences in the growth rates or maximum diameters of abnormal follicles that had different outcomes, but oestradiol concentrations were greater in prolonged follicles that ovulated compared with those follicles that persisted (P = 0.06). In conclusion, stimulation with ACTH resulted in a marked deviance from normal follicular activity. The aberrations were probably caused by the interruption of pulsatile secretion of LH (but not FSH) leading to decreased but prolonged oestradiol secretion.
Follicular fluid rheology and the duration of the ovulatory process
Authors: Luck MR , Ye J , Almislimani H , Hibberd S
Published: January 2004

The fluid dynamics of ovulation were investigated to understand the mechanical role of follicular fluid in oocyte release. A set of equations describing the flow of fluid from an evacuating follicle was derived from basic principles. These equations demonstrate that, subject to assumptions about the available pressure differential and the source of the expulsive force, the size and shape of the ovulatory orifice have the largest influences on the rate of fluid loss, although the viscosity of the fluid is also an important variable. A thorough rheological examination of pig, bovine and human follicular fluids, performed using a cone-plate viscometer, demonstrated that these fluids have complex, non-Newtonian characteristics. The fluids also undergo time-dependent and spontaneous changes in viscosity at constant shear rates; some fluids were subject to coagulation-like events. Viscosity characteristics were unrelated to broad parameters of follicle development. The models used representative viscosity values to demonstrate that variations in the rate and duration of follicle evacuation, as observed by ultrasonography, could be explained largely by variations in fluid viscosity and the characteristics of the ovulatory orifice.
Uterine eosinophils and reproductive performance in interleukin 5-deficient mice
Authors: Robertson SA , Mau VJ , Young IG , Matthaei KI
Published: January 2004

Interleukin 5 is expressed in type 2 T lymphocytes and has a key role in driving the differentiation, recruitment and activation of eosinophils. Mice with a null mutation in the interleukin 5 gene (IL-5 -/- mice) have altered type 2 immune responses and severely depleted eosinophil populations. In the present study, the effect of interleukin 5 deficiency on the abundant population of eosinophils present in the female reproductive tract was investigated, and the reproductive performance in C57Bl/6 IL-5 -/- mice was measured. Endometrial eosinophils, detected on the basis of their endogenous peroxidase activity, were reduced in number by four-sevenfold during the oestrous cycle and in early pregnancy in IL-5 -/- mice. Eosinophils present in the cervix and decidual tissues at the time of parturition were similarly diminished. The temporal fluctuations in eosinophil recruitment and localization within these tissues were otherwise unchanged, indicating that interleukin 5 is not a necessary chemotactic agent in the female reproductive tract. Oestrous cycles were moderately greater in duration in IL-5 -/- mice (mean +/- SD = 5.6 +/- 1.0 days in IL-5 -/- mice versus 5.0 +/- 0.8 days in IL-5 +/+ mice), owing to an extended period in oestrus (2.7 +/- 0.9 days per cycle in IL-5 -/- mice versus 1.8 +/- 0.7 in IL-5 +/+ mice). The interval between placing females with males and the finding of copulatory plugs was reduced significantly in interleukin 5-deficient mice. Implantation rates and subsequent fetal development were comparable in IL-5 -/- and IL-5 +/+ mice, irrespective of whether pregnancies were sired by syngeneic (C57Bl/6) or allogeneic (CBA or Balb/c) males, apart from a 10% increase in placental size and a 6.5% decrease in placental∶fetal ratio seen on day 17 in pregnancies sired by CBA males. Parturition and post-partum uterine repair were not compromised in interleukin 5-deficient mice, as judged by the length of gestation, and the outcomes of pregnancies initiated at post-partum oestrus. The birth weights and growth trajectories of pups were significantly influenced by interleukin 5 status, with small but significant increases in the weights of IL-5 -/- pups, particularly C57Bl/6 and CBA F(1) animals, remaining evident until adulthood. These data are consistent with the view that eosinophils have a role in endometrial tissue remodelling associated with the oestrous cycle, but indicate that the events of pregnancy and parturition proceed quite normally in the absence of maternal and fetal interleukin 5. However, strain-dependent effects of interleukin 5 deficiency on placental growth and function and subsequent weight gain in the newborn indicate that this cytokine may act through the maternal or fetal immune axis to exert subtle influences on reproductive outcome.
Spermatogenesis and testicular tumours in ageing dogs
Authors: Peters MA , de Rooij DG , Teerds KJ , van Der Gaag I , van Sluijs FJ
Published: January 2004

Spermatogenesis was examined in testes from 74 dogs of various breeds without clinically detected testicular disease. A modified Johnsen score system was used to determine whether spermatogenesis deteriorates with ageing. The diameter of seminiferous tubules was measured in dogs without testicular disease to examine other possible effects of ageing on tubular performance. There appeared to be no relation between age and these variables. The influence of testicular tumours on spermatogenesis was also investigated in both affected and unaffected testes. The testes of 28 dogs with clinically palpable tumours and 21 dogs with clinically non-palpable tumours were investigated. In cases of unilateral occurrence of a tumour, impairment of spermatogenesis was observed only in the affected testis of dogs with clinically detected tumours. Bilateral occurrence of tumours, whether detected clinically or non-clinically, was associated with severe impairment of spermatogenesis. The prevalence of tumours increased during ageing. Eighty-six per cent of the clinically detected and 57% of the non-clinically detected tumours were found in old dogs. Multiple types of tumour and bilateral occurrence were very common. Seminomas and Leydig cell tumours were more frequent than Sertoli cell tumours. It was concluded that spermatogenesis per se did not decrease during ageing in dogs but the occurrence of testicular tumours increased with ageing and affected spermatogenesis significantly, as reflected by a lower Johnsen score.
Carbon‐Nanotube‐Reinforced Zr‐Based Bulk Metallic Glass Composites and Their Properties
Authors: Bian Z. , Wang R. J. , Wang W. H. , Zhang T. , Inoue A.
Published: January 2004

In this paper, we systematically report the preparation of carbon‐nanotube (CNT)‐reinforced Zr‐based bulk metallic glass (BMG) composites. The physical and mechanical properties of the composites were investigated. Compressive testing shows that the composites still display high fracture strength. Investigation also shows that the composites have strong ultrasonic attenuation characteristics and excellent wave absorption ability. The strong wave absorption implies that CNT‐reinforced Zr‐based BMG composites, besides their excellent mechanical properties, may also have significant potential for applications in shielding acoustic sound or environmental noise.
Microtubule‐Templated Biomimetic Mineralization of Lepidocrocite
Authors: Boal A. K. , Headley T. J. , Tissot R. G. , Bunker B. C.
Published: January 2004

Protein microtubules (MTs) 25 nm in diameter and tens of micrometers long have been used as templates for the biomimetic mineralization of FeOOH. Exposure of MTs to anaerobic aqueous solutions of Fe2+ buffered to neutral pH followed by aerial oxidation leads to the formation of iron oxide coated MTs. The iron oxide layer was found to grow via a two‐step process: initially formed 10–30 nm thick coatings were found to be amorphous in structure and comprised of several iron‐containing species. Further growth resulted in MTs coated with highly crystalline layers of lepidocrocite with a controllable thickness of up to 125 nm. On the micrometer size scale, these coated MTs were observed to form large, irregular bundles containing hundreds of individually coated MTs. Iron oxide grew selectively on the MT surface, a result of the highly charged MT surface that provided an interface favorable for iron oxide nucleation. This result illustrates that MTs can be used as scaffolds for the in‐situ production of high‐aspect‐ratio inorganic nanowires.
Designed Self‐Assembled β‐Sheet Peptide Fibrils as Templates for Silica Nanotubes
Authors: Meegan J. E. , Aggeli A. , Boden N. , Brydson R. , Brown A. P. , Carrick L. , Brough A. R. , Hussain A. , Ansell R. J.
Published: January 2004

Sol–gel condensation of tetraethoxysilane in the presence of designed self‐assembled β‐sheet peptide fibril templates, followed by template extraction, yields hollow silica nanotubes. The nanotubes are hundreds of nanometers long and possess a central pore of ∼ 3.5 nm, determined by the fibril template diameter. The effects of synthesis conditions have been investigated and the resultant silica materials characterized by various techniques.

Silica nanostructures with various morphologies have been produced previously using supramolecular organic assemblies as templates. Hollow nano‐ or microtubes, which may have applications in separations, catalysis, nano‐optics, and ‐electronics have been of particular interest. Peptide‐based templates are especially interesting because of their relevance to biological silica microstructure formation. The new fibrillar peptide templates described here have the advantages of prescribed diameter, twist pitch, and handedness, which should impart chirality on the resulting silica nanotubes, providing control of the internal surface architecture by appropriate peptide design.
Optimization of a Quasi‐Solid‐State Dye‐Sensitized Photoelectrochemical Solar Cell Employing a Ureasil/Sulfolane Gel Electrolyte
Authors: Stathatos E. , Lianos P. , Surca Vuk A. , Orel B.
Published: January 2004

A quasi‐solid‐state, dye‐sensitized photoelectrochemical solar cell employing a gel electrolyte obtained by sol–gel chemistry is described. The gel electrolyte is based on a ureasil precursor (i.e., a poly(propylene oxide) oligomer end‐capped by triethoxysilane groups through urea bridges) and sulfolane and it incorporates the I3–/I– redox couple. It is shown that the combination of these two reagents prevents crystallization of KI, thus ensuring a long life for the cell and a satisfactory overall efficiency that surpasses 5 %. Cell efficiency increases with temperature. Optimization of gel‐electrolyte performance has been obtained by studying mobility with fluorescence‐quenching techniques complemented by direct‐current conductivity measurements.
Peptide Templates for Nanoparticle Synthesis Derived from Polymerase Chain Reaction‐Driven Phage Display
Authors: Naik R. R. , Jones S. E. , Murray C. J. , McAuliffe J. C. , Vaia R. A. , Stone M. O.
Published: January 2004

Phage peptide display libraries are commonly used to select peptides that bind to inorganic surfaces (metals, metal oxides, and semiconductors). These binding peptides can serve as templates to control the nucleation and growth of inorganic nanoparticles in vitro. In this report, we describe the identification of a unique set of sequences that bind to silver and cobalt nanoparticles from a phage peptide display library using a polymerase chain reaction (PCR)‐driven method. The amino acid sequences obtained by the PCR method are a distinct set of sequences that would otherwise be missed using the regular panning method. Peptides identified by the method described here are also shown to function as templates for the synthesis of silver and cobalt platinum nanoparticles.
The Singlet–Triplet Exchange Energy in Conjugated Polymers
Authors: Köhler A. , Beljonne D.
Published: January 2004

Electron–electron interactions in organic semiconductors split the lowest singlet and triplet states by the exchange energy, ΔEST. Measurement of singlet and triplet emission spectra in a large number of conjugated polymers yield an almost constant ΔEST value close to 0.7 eV. This is in contrast to the situation in molecules, where the exchange energy is found to depend on molecular size and to vary over a wide range. Quantum‐chemical calculations are performed to address the origin of the constant exchange energy in phenylene‐based conjugated polymers. The electron–hole separation in the lowest singlet and triplet excited states is found to be independent of the π‐conjugated backbone, and saturates for chains longer than a few repeating units, resulting in a constant exchange energy. In shorter conjugated oligomers, confinement of the excitations destabilizes the singlet with respect to the triplet through exchange interactions and leads to a larger and size‐dependent singlet–triplet energy separation.
Synthesis of ZSM‐5 Films and Monoliths with Bimodal Micro/Mesoscopic Structures
Authors: Cho S. I. , Choi S. D. , Kim J.‐H. , Kim G.‐J.
Published: January 2004

A route to synthesize ZSM‐5 crystals with a bimodal micro/mesoscopic pore system has been developed in this study; the successful incorporation of the mesopores within the ZSM‐5 structure was performed using tetrapropylammonium hydroxide (TPAOH)‐impregnated mesoporous materials containing carbon nanotubes in the pores, which were encapsulated in the ZSM‐5 crystals during a solid rearrangement process within the framework. Such mesoporous ZSM‐5 zeolites can be readily obtained as powders, thin films, or monoliths.
Emission Characteristics and Performance Comparison of Polyfluorene Lasers with One‐ and Two‐Dimensional Distributed Feedback
Authors: Heliotis G. , Xia R. , Turnbull G. A. , Andrew P. , Barnes W. L. , Samuel I. D. W. , Bradley D. D. C.
Published: January 2004

We report the fabrication of optically pumped solid‐state polymer lasers based on the semiconducting polymer poly(9,9‐dioctylfluorene) (PFO) using resonator structures that offer one‐ and two‐dimensional distributed feedback. The lasers are readily fabricated by solution deposition of thin polymer films on top of suitable grating microstructures etched into fused silica substrates. The devices operate in the blue spectral region, are highly efficient (slope efficiencies as high as 7.8 % are demonstrated), and exhibit very low threshold energies for oscillation (0.8 nJ per pulse). The operating characteristics of the lasers are investigated in detail. The transverse mode profiles and divergence of the output beams are measured and correlated with the internal lasing modes and the feedback mechanism present in the resonators. Additionally, broadband tuning of the emission wavelength over a range of ∼ 40 nm is demonstrated by controlling the supported resonant frequency of the laser cavities.
Templated Synthesis of Carbon Nanofibers from Polyacrylonitrile Using Sepiolite
Authors: Fernández‐Saavedra R. , Aranda P. , Ruiz‐Hitzky E.
Published: January 2004

Carbon nanofibers of ca. 1 μm by 20 nm dimensions have been successfully prepared by an improved route, consisting of the graphitization of polyacrylonitrile (PAN) previously formed inside the nanosized pores of sepiolite. This natural microfibrous silicate contains structural tunnels extending along the whole fiber, which are able to include acrylonitrile (AN). This is polymerized to give polyacrylonitrile (PAN), which is further thermally treated to form carbon nanofibers inside the pores. We have clearly shown the mechanisms and the role of the structural tunnels of sepiolite in the adsorption, polymerization, and graphitization of AN by applying spectroscopic techniques as FTIR spectroscopy, 13C NMR spectroscopy, in‐situ EIS (electrochemical impedance spectroscopy), and other structural, textural, and analytical tools (powder X‐ray diffraction (PXRD), scanning transmission electron microscopy–energy‐dispersive X‐ray analysis (STEM–EDX), differential thermal analysis (DTA), thermogravimetric analysis (TG), N2 isotherms, etc.). The resulting solids constitute a new class of conductive carbon–clay nanocomposites, useful for applications in diverse electrochemical devices such as lithium batteries, sensors, or electrocatalysts.
Tuning the Electronic Structure and Solubility of Conjugated Polymers with Perfluoroalkyl Substituents: Poly(3‐perfluorooctylthiophene), the First Supercritical CO2‐soluble Conjugated Polymer
Authors: Li L. , Counts K. E. , Kurosawa S. , Teja A. S. , Collard D. M.
Published: January 2004

Poly(3‐perfluorooctylthiophene) is the first reported conjugated polymer that is soluble in supercritical carbon dioxide (see Figure). The electron‐withdrawing nature of the perfluoroalkyl groups affords a material that undergoes reversible reduction (n‐doping), and the polymer displays a large Stokes shift because of a large difference in the conformation of the ground state and a more planar excited state.
Carbon‐Encapsulated Radioactive 99mTc Nanoparticles
Authors: Chan H. B. S. , Ellis B. L. , Sharma H. L. , Frost W. , Caps V. , Shields R. A. , Tsang S. C.
Published: January 2004

A macroscopic quantity of quasi‐spherical fullerene‐like shells (see Figure) that encapsulate iron nanoparticles containing radioisotope 99mTc are prepared for the first time. The nanocomposite is acid‐non‐leachable, retaining radioactivity at an extremely high level. This method will enable rigorous studies of what are currently theoretical descriptions of nanometer‐scale medicinal delivery vehicles for diagnostic and therapeutic purposes.
Water‐Based Single‐Walled‐Nanotube‐Filled Polymer Composite with an Exceptionally Low Percolation Threshold
Authors: Grunlan J. C. , Mehrabi A. R. , Bannon M. V. , Bahr J. L.
Published: January 2004

An emulsion polymer (i.e., latex) has been used as the polymer matrix starting material in order to lower the percolation threshold of single‐walled‐carbon‐nanotube (SWNT)‐filled polymer composites (e.g., see Figure). A percolation threshold below 0.04 wt.‐% SWNT is achieved. This composite system offers the potential for conductive polymers that are relatively inexpensive, mechanically robust, environmentally stable, and easy to process.
Highly Efficient Single‐Layer Polymer Electrophosphorescent Devices
Authors: Yang X. , Neher D. , Hertel D. , Däubler T. K.
Published: January 2004

A commercially available Ir complex has been employed for the preparation of highly efficient (see Figure) single‐layer phosphorescent polymer light‐emitting diodes by use of appropriate thermal treatment and proper adjustment of the layer composition. These devices exhibit essentially no dependence of the driving field on the concentration of the Ir complex, suggesting that the build‐up of space‐charge in the layer is insignificant.
Pressure‐Assisted Capillary Force Lithography
Authors: Khang D.‐Y. , Lee H. H.
Published: January 2004

Pressure‐assisted capillary force lithography is introduced using a permeable fluoropolymer material as a mold. Slight pressing (∼ 2–3 bar), when combined with a newly developed experimental set‐up, ensures conformal contact between the stiff fluoropolymer mold and the substrate. The stiff nature of the mold material makes it possible to pattern sub‐100 nm features (see Figure and cover).
Multibit Memory Using Self‐Assembly of Mixed Ferrocene/Porphyrin Monolayers on Silicon
Authors: Li Q. , Mathur G. , Gowda S. , Surthi S. , Zhao Q. , Yu L. , Lindsey J. S. , Bocian D. F. , Misra V.
Published: January 2004

An alternative strategy for achieving multi‐bit functionality, which uses mixed self‐assembled monolayers of a benzyl alcohol‐tethered ferrocene (Fc‐BzOH) and a benzyl alcohol‐tethered porphyrin (Por‐BzOH) on silicon surfaces to achieve a four‐state (2‐bit) memory element, is presented. The four states include the neutral state and three distinct cationic states obtained upon oxidation of Fc‐BzOH (monopositive) and Por‐BzOH (monopositive, dipositive) molecules. Conventional cyclic voltammetry, capacitance, and conductance methods have been used to characterize the mixed monolayer.
Continuously Color‐Tunable Rubber Laser
Authors: Weinberger M. R. , Langer G. , Pogantsch A. , Haase A. , Zojer E. , Kern W.
Published: January 2004

A photopatternable elastomer [poly(butadiene‐co‐(4‐vinylbenzyl thiocyanate)] bearing UV‐sensitive thiocyanate (–SCN) groups, which isomerize to isothiocyanate (–NCS) units upon irradiation with UV light, is reported. This isomerization changes the refractive index of the elastomer, enabling the production of refractive index and relief distributed feedback (DFB) gratings using interference lithography. Blending a laser dye into the elastomer creates an optically pumped laser, which, when strained, allows continuous and reversible tuning of the laser emission wavelength.
A Color‐Neutral, Gd Nanoparticle Switchable Mirror with Improved Optical Contrast and Response Time
Authors: Aruna I. , Mehta B. R. , Malhotra L. K. , Shivaprasad S. M.
Published: January 2004

An all‐round improvement of the switchable mirror characteristics of any rare earth metal system can be achieved by utilizing two characteristics of nanoparticles: the size‐dependent blue shift in the absorption edge and large surface area. Gd nanoparticles show better color neutrality in comparison with polycrystalline, alloy, and multilayer films, and also exhibit increased optical contrast and faster response time than polycrystalline films.
Compliant, Robust, and Truly Nanoscale Free‐Standing Multilayer Films Fabricated Using Spin‐Assisted Layer‐by‐Layer Assembly
Authors: Jiang C. , Markutsya S. , Tsukruk V. V.
Published: January 2004

Free‐standing multilayer gold‐nanoparticle containing films with an overall thickness ranging from 20–70 nm have been fabricated. These films are compliant, robust, and long‐living, and can be manufactured very time‐efficiently with spin‐assisted layer‐by‐layer assembly with an exceptionally high level of uniformity and integrity, which facilitate their ability to sustain multiple elastic deformations (see Figure).
Rational Design of Macrocellular Silica Scaffolds Obtained by a Tunable Sol–Gel Foaming Process
Authors: Carn F. , Colin A. , Achard M.‐F. , Deleuze H. , Saadi Z. , Backov R.
Published: January 2004

A technique that uses a non‐static patterning method has been employed for rational design toward macrocellular silica scaffolds (see Figure). The technique allows complete control over the width, length, and curvature of the plateau borders of the silica foam. Furthermore, this macroscale void space structuration is associated with secondary micro‐ and mesoscale porosity thus reaching hierarchically organized monolith‐type materials.
Ultra‐High‐Density Photochromic Main‐Chain 1,2‐Dithienylcyclopentene Polymers Prepared Using Ring‐Opening Metathesis Polymerization
Authors: Wigglesworth T. J. , Branda N. R.
Published: January 2004

Ring‐opening metathesis polymerization is used to construct the well‐known photoresponsive 1,2‐dithienylethene backbone for the generation of ultra‐high‐density photochromic main‐chain polymers (see Figure). The photochromic monomer unit can be easily functionalized to create polymers with diverse structural and electronic properties. Both lipophilic and hydrophilic versions of the polymer have been prepared.
Logic Control of the Fluorescence of a New Dyad, Spiropyran‐Perylene Diimide‐Spiropyran, with Light, Ferric Ion, and Proton: Construction of a New Three‐Input “AND” Logic Gate
Authors: Guo X. , Zhang D. , Zhu D.
Published: January 2004

The fluorescence of a novel dyad with spiropyran and perylene diimide units can be significantly enhanced only under the combined actions of UV light, protons, and ferric ions (see Figure). This behavior corresponds to a new “AND” gate with three inputs.
Growth and Field‐Emission Properties of Crystalline, Thin‐Walled Carbon Microtubes
Authors: Hu J. Q. , Bando Y. , Xu F. F. , Li Y. B. , Zhan J. H. , Xu J. Y. , Golberg D.
Published: January 2004

A crystalline graphitic structure—uniform diameter, thin‐walled carbon microtubes (see Figure)—has been prepared via a thermal reaction between ZnS and activated carbon. The microtubes have outer diameters of ∼ 1–2 μm, wall thicknesses of 10–20 nm, and lengths from several hundreds of micrometers to millimeters. The field‐emission turn‐on of the carbon microtubes is as low as ∼ 1.0–1.3 V μm–1.
Amide Derivatives of [6‐(5‐Methyl‐3‐phenylpyrazole‐1‐yl)‐3(2H)‐pyridazinone‐2‐yl]acetic Acids as Potential Analgesic and Anti‐Inflammatory Compounds
Authors: Banoglu Erden , Akoğlu Çağla , Ünlü Serdar , Küpeli Esra , Yeşilada Erdem , Şahin M. Fethi
Published: January 2004

In this study, amide derivatives of [6‐(5‐methyl‐3‐phenyl‐pyrazole‐1‐yl)‐3(2H)‐pyridazinone‐2‐yl]acetic acid were synthesized and tested for their in vivo analgesic and anti‐inflammatory activity by using the p‐benzoquinone‐induced writhing test and carrageenan‐induced hind paw edema model, respectively. The analgesic and anti‐inflammatory activity of the compounds 6a, 6d, 6e, 6g, 6h and 6m were more potent than that of aspirin as an analgesic and indomethacin as an anti‐inflammatory drug, respectively. The other derivatives generally resulted in comparable activity to reference compounds. Inhibitor activity of the active compounds on cyclooxygenase isoforms was also investigated by using in vitro human whole blood assay and found that these derivatives did not exert their analgesic and anti‐inflammatory activities through COX inhibition and other mechanisms might be involved.
Synthesis and Structure‐Activity Relationships of 4‐Cycloalkylamino‐1, 2, 4‐triazolo[4, 3‐a]quinoxalin‐1‐ one Derivatives as A1 and A3 Adenosine Receptor Antagonists
Authors: Colotta Vittoria , Catarzi Daniela , Varano Flavia , Filacchioni Guido , Martini Claudia , Trincavelli Letizia , Lucacchini Antonio , Colotta Vittoria
Published: January 2004

In a previous paper (Colotta V. et al., J. Med. Chem. 2000, 43, 1158—1164) we reported the synthesis and binding activity of 4‐cycloalkylamino‐1, 2, 4‐triazolo[4, 3‐a]quinoxalin‐1‐one derivatives, differently substituted on the appended 2‐phenyl ring, some of which were potent and selective A1 adenosine receptor (AR) antagonists. In the present paper several 4‐cycloalkylamino‐2‐phenyl‐1, 2, 4‐triazolo[4, 3‐a]quinoxalin‐1‐one derivatives (1—11), bearing simple substituents on the benzofused moiety, are reported. The binding data of bovine A1 and A2A and human A3 AR show that we have obtained highly potent A1 AR antagonists. In particular, the 4‐cyclohexylamino derivatives 1—5 show higher A1 vs A2A selectivity than the parent compound A, which lacks substituents on the benzofused moiety. Moreover, compounds 1—11 display, in general, good A3 AR affinity. Finally, SAR studies provide some new insights about the steric requirements of the A3 receptor pocket, which accommodates the benzofused moiety of our 4‐amino‐triazoloquinoxalin‐1‐one derivatives.
Flow calorimetry and dielectric spectroscopy to control the bacterial conversion of toxic substrates into polyhydroxyalcanoates
Authors: Maskow Thomas , Olomolaiye Dayo , Breuer Uta , Kemp Richard
Published: January 2004

The microbial conversion of toxic substrates into valuable products in continuous culture requires the equivalent of a tight rope walk between formation of the desired product and intoxication of the microbial catalyst. The condition of the latter is reflected immediately by changes in heat flow rate and β‐dispersion in an electrical RF field. Therefore, these were applied to the example of the continuous growth‐associated synthesis of polyhydroxyalcanoates (PHA) from phenol by the bacterial strain Variovorax paradoxus DSM 4065. By controlling the supply of phenol to the chemostat, the rates of degradation, biomass formation, and synthesis of target product, respectively, were increasingly elevated until the onset of poisoning the organisms. The boundary between the maximum rates and the initiation of intoxication coincided with a sudden change in the heat flux. Using this occurrence, it was possible to develop a control strategy and test it successfully for a time period of 80 h. After 40 h the process stabilized at mean values, i.e., at rates of 92% phenol degradation, 100% biomass formation, and 70 – 75% of PHA formation compared with the situation shortly before poisoning the organisms. Using a moving‐average technique to filter the raw dielectric spectroscope data, changes were followed in biomass concentration of approximately 100 mg/L. However, this technique was not sensitive or rapid enough to control the process. © 2004 Wiley Periodicals, Inc.
Milking microalga Dunaliella salina for β‐carotene production in two‐phase bioreactors
Authors: Hejazi M. A. , Holwerda E. , Wijffels R. H.
Published: January 2004

A new method was developed for production of β‐carotene from Dunaliella salina. Cells were grown in low light intensity and then transferred to a production bioreactor illuminated at a higher light intensity. It was a two‐phase bioreactor consisting of an aqueous and a biocompatible organic phase. Mixing of the cells and extraction were performed by recirculation of the organic phase. Two experiments were performed. In the first experiment, bioreactors were operated at two different solvent recirculation rates of 150 and 200 mL min−1. The β‐carotene extraction rate increased significantly at the higher recirculation rate, without exerting any influence on cell number and viability. A second experiment was carried out at a recirculation rate (200 mL min−1) appropriate for the study of long‐term production of β‐carotene. The results show that D. salina at high light intensity remained viable for a long period (>47 days) in the presence of a biocompatible organic phase; however, cell growth was very slow. β‐Carotene could be continuously extracted to the organic phase; the cells continued to produce β‐carotene and the extracted molecules were continuously reproduced. As a result, β‐carotene was continuously removed (“milked”) from the cells. β‐Carotene extraction efficiency in this system was >55%, and productivity was 2.45 mg m−2 day−1, much higher than that of commercial plants. © 2004 Wiley Periodicals, Inc.
Rabies virus production in high vero cell density cultures on macroporous microcarriers
Authors: Yokomizo A. Y. , Antoniazzi M. M. , Galdino P. L. , Azambuja N. , Jorge S. A. C. , Pereira C. A.
Published: January 2004

The purpose of the study was to investigate the rabies virus multiplication in Vero cell cultures performed on porous microcarriers, MCs (cellulose–Cytopore and gelatin–Cultispher G), which provide higher available surface area compared with solid (nonporous) MCs (DEAE–Cytodex 1). In a set of experiments performed at the same MC concentration (MCs per milliliter), cell densities regularly obtained in porous MC cultures were comparable, but almost twice as high as those in solid MC cultures. In addition, 41.1 ± 3.9‐, 35.2 ± 2‐, and 19.6 ± 5.8‐fold increases in cell concentration, relative to the initial cell number, along with maximum rabies virus titers of 6.3 ± 0.3 × 104, 5 ± 0.1 × 104, and 4.3 ± 0.2 × 104 FFD50/mL were observed in Cytopore, Cultispher G, and Cytodex 1 MC cultures, respectively. When higher concentrations of MCs were employed, lower performances of virus production and MC‐cell occupation (cells per MC or cells per square millimeter) were observed. Cell attachment to MCs was shown to be faster for Cytopore MCs and Cytodex 1 MCs than for Cultispher G MCs. Concerning the kinetics of cell multiplication on MCs, exponential cell growth, at similar specific cell growth rates, took place on Cytopore, Cultispher G, and Cytodex 1 MCs. In addition, cell densities as high as 2.1 ± 0.2 × 106 cells/mL on Cytopore MCs, 1.8 ± 0.1 × 106 cells/mL on Cultispher G MCs, and 1 ± 0.3 × 106 cells/mL on Cytodex 1 MCs were regularly obtained in batch cultures. Optical as well as scanning and transmission electron microscopy studies carried out to analyze MC structure, MC cell occupation, and cell permissivity to virus infection demonstrated that there was uniform cell distribution in the external and internal areas of the MCs, suggesting an efficiency of virus synthesis. Our results indicate the usefulness of these supports for rabies virus antigen production, as well as possibilities for further optimization. © 2004 Wiley Periodicals, Inc.
Mosquito and mammalian cells grown on microcarriers for four‐serotype dengue virus production: Variations in virus titer, plaque morphology, and replication rate
Authors: Liu Chia‐Chyi , Wu Suh‐Chin
Published: January 2004

Dengue (DEN) viruses consisting of four distinct serotypes cause diseases such as dengue fever, dengue hemorrhagic fever, and dengue shock syndrome in humans. Most of the dengue viruses can be effectively propagated in some mosquito and mammalian cell lines. In this study, we applied microcarrier cell culture technology to study two relevant aspects involving dengue virus, one on biotechnology of cell growth and virus production, and the other on virus biology concerning genetic variation of a virus population. We investigated the growth of C6/36 mosquito cells and Vero cells grown on Cytodex 1 microcarriers. High‐titer DEN virus production can be achieved in C6/36 and Vero cells infected at low cell inoculation density, in the lag‐phase cell stage, and at low multiplicity of infection (MOI). The maximum titers produced for DEN‐1, DEN‐3, and DEN‐4 viruses were approximately 10‐ to 10,000‐fold lower than for DEN‐2 virus produced in C6/36 and Vero cells grown on microcarriers. The DEN‐2 virus produced in C6/36 cells displayed far more extensive plaque heterogeneity than in Vero cells. Microcarrier C6/36 mosquito cell culture appeared to be the most effective system for four‐serotype DEN virus production. Interestingly, some selected variants of DEN virus may outgrow in Vero cells when using a T‐flask culture. These results may provide useful information for DEN vaccine development. © 2004 Wiley Periodicals, Inc.
Removal of Mn(II) ions from aqueous neutral media by manganese‐oxidizing fungus in the presence of carbon fiber
Authors: Sasaki Keiko , Konno Hidetaka , Endo Mai , Takano Keishi
Published: January 2004

A manganese‐oxidizing fungus was isolated from a hot spring in Japan. The fungus was increasingly effective at oxidizing Mn(II) ions as the concentration of organic carbon sources in the growth medium was decreased. The fungus oxidized 50 ppm of Mn(II) ions within 160 h in a pH 7.3 medium at 25°C. The presence of carbon fiber shortened the time to 80 h, and promoted steady oxidation. The oxidation products were identified by XPS and XRD to be poorly crystallized and amorphous MnO2, both with and without the fiber. These results suggest that the fiber participates in kinetically limited oxidation. The fungus was entangled with and clung to the fibers, and the oxidized Mn species accumulated on the fungus. Similarly shaped polyethylene telephthalate fiber did not enhance the oxidation, nor was adhesion of the fungus observed. Although the mechanism is still unknown, the present work shows that removal of Mn from solution through the precipitation and accumulation of Mn‐oxides on the fungus in the presence of carbon fiber is a promising improvement for water treatment. © 2004 Wiley Periodicals, Inc.
Combinatorial formulation of biocatalyst preparations for increased activity in organic solvents: Salt activation of penicillin amidase
Authors: Lindsay John P. , Clark Douglas S. , Dordick Jonathan S.
Published: January 2004

A combinatorial experimental technique was used to identify salts and salt mixtures capable of activating penicillin amidase in organic solvents for the transesterification of phenoxyacetate methyl ester with 1‐propanol. Penicillin amidase was lyophilized in the presence of various chloride and acetate salts within 96‐deep‐well plates and catalytic rates measured to determine lead candidates for highly salt‐activated preparations. The kinetics of the most active formulations were then further evaluated. These studies revealed that a formulation consisting of 98% (w/w) of a 1:1 KAc:CsCl salt mixture, 1% (w/w) enzyme, and 1% (w/w) potassium phosphate buffer was ∼35,000‐fold more active than the salt‐free formulation in hexane, as reflected in values of Vmax/Km. This extraordinary activation could be extended to more polar solvents, including tert‐amyl alcohol, and to formulations with lower total salt contents. A correlation was found between the kosmotropic/chaotropic behavior of the salts (as measured by the Jones‐Dole B coefficients) and the observed activation. Strongly chaotropic cations combined with strongly kosmotropic anions yielded the greatest activation, and this is likely due to the influence of the ions on protein–water and protein–salt interactions. © 2004 Wiley Periodicals, Inc.
Thermal and enzymatic pretreatment of sludge containing phthalate esters prior to mesophilic anaerobic digestion
Authors: Gavala Hariklia N. , Yenal Umur , Ahring Birgitte K.
Published: January 2004

The present study aimed at investigating the effect of thermal pretreatment of sludge at 70°C on the anaerobic degradation of three commonly found phthalic acid esters (PAE): di‐ethyl phthalate (DEP), di‐butyl phthalate (DBP), and di‐ethylhexyl phthalate (DEHP). Also, the enzymatic treatment at 28°C with a commercial lipase was studied as a way to enhance PAE removal. Pretreatment at 70°C of the sludge containing PAE negatively influenced the anaerobic biodegradability of phthalate esters at 37°C. The observed reduction of PAE biodegradation rates after the thermal pretreatment was found to be proportional to the PAE solubility in water: the higher the solubility, the higher the percentage of the reduction (DEP > DBP > DEHP). PAE were slowly degraded during the pretreatment at 70°C, yet this was probably due to physicochemical reactions than to microbial/biological activity. Therefore, thermal pretreatment of sludge containing PAE should be either avoided or combined with a treatment step focusing on PAE reduction. On the other hand, enzymatic treatment was very efficient in the removal of PAE. The enzymatic degradation of DBP, DEP, and DEHP could be one to two orders of magnitude faster than under normal mesophilic anaerobic conditions. Moreover, the enzymatic treatment resulted in the shortest half‐life of DEHP in sludge reported so far. Our study further showed that enzymatic treatment with lipases can be applied to raw sludge and its efficiency does not depend on the solids concentration. © 2004 Wiley Periodicals, Inc.
High‐level accumulation of a recombinant antibody fragment in the periplasm of Escherichia coli requires a triple‐mutant (degP prc spr) host strain
Authors: Chen Christina , Snedecor Brad , Nishihara Julie C. , Joly John C. , McFarland Nancy , Andersen Dana C. , Battersby John E. , Champion Kathleen M.
Published: January 2004

During production of a humanized antibody fragment secreted into the periplasm of Escherichia coli, proteolytic degradation of the light chain was observed. In order to determine which protease(s) were responsible for this degradation, we compared expression of the F(ab′)2 antibody fragment in several E. coli strains carrying mutations in genes encoding periplasmic proteases. Analysis of strains cultured in high cell density fermentations showed that the combination of mutations in degP prc spr was necessary for the cells to produce high levels of the desired recombinant antibody fragment. In order to eliminate the possible effects of mutations in other genes, we constructed E. coli strains with protease mutations in isogenic backgrounds and repeated the studies in high cell density fermentations. Extensive light chain proteolysis persisted in degP strains. However, light chain proteolysis was substantially decreased in prc and prc spr strains, and was further decreased with the introduction of a degP mutation in prc and prc spr mutant strains. These results show that the periplasmic protease Prc (Tsp) is primarily responsible for proteolytic degradation of the light chain during expression of a recombinant antibody fragment in E. coli, and that DegP (HtrA) makes a minor contribution to this degradation as well. The results also show that spr, a suppressor of growth defects in prc strains, is required for a prc mutant to survive throughout high cell density fermentations. © 2004 Wiley Periodicals, Inc.
Inadvertent perforation during rectal cancer resection in Norway
Authors: Eriksen M T , Wibe A , Syse A , Haffner J , Wiig J N
Published: January 2004

Background

Inadvertent perforation of the bowel or tumour is a relatively common complication during resection of rectal cancer. The purpose of this study was to examine intraoperative perforation following the introduction of mesorectal excision as a standard surgical technique in Norway.

Methods

This was a prospective national cohort study of 2873 patients undergoing major resection of rectal carcinoma at 54 Norwegian hospitals from November 1993 to December 1999.

Results

The overall perforation rate was 8·1 per cent (234 of 2873 patients). In a multivariate analysis, the risk of perforation was significantly greater in patients undergoing abdominoperineal resection (odds ratio (OR) 5·6 (95 per cent confidence interval (c.i.) 3·5 to 8·8)) and in those aged 80 years or more (OR 2·0 (95 per cent c.i. 1·2 to 3·5)). The 5-year local recurrence rate was 28·8 per cent following perforation, compared with 9·9 per cent in patients with no perforation (P < 0·001); survival rates were 41·5 and 67·1 per cent respectively (P < 0·001).

Conclusion

The risk of intraoperative perforation was significantly greater in patients with rectal cancer undergoing abdominoperineal resection and in those aged 80 years or more. The high local recurrence rates and reduced survival following perforation call for increased attention to avoid this complication.
Matched study of three methods for palliation of malignant pyloroduodenal obstruction
Authors: Mittal A , Windsor J , Woodfield J , Casey P , Lane M
Published: January 2004

Background

The traditional management of pyloroduodenal obstruction is open gastrojejunostomy (OGJ). More recently laparoscopic gastrojejunostomy (LGJ) and endoscopic stenting (ES) have been introduced. The aim of this study was to evaluate the three approaches to the palliation of malignant pyloroduodenal obstruction.

Methods

All patients who underwent surgery (open and laparoscopic) for malignant pyloroduodenal obstruction at Auckland City Hospital between 1989 and 2002 inclusive were identified from International Classification of Diseases (ICD) 10 codes and from the Otago Surgical Audit Database. Patients who had an endoscopic stent were identified from the Endoscribe database. A review of medical records was conducted and data recorded in a structured pro forma. There were 181 patients with malignant pyloroduodenal obstruction of whom 56 patients had OGJ, 14 had LGJ and 16 had ES. Patients in the LGJ and ES groups were matched with those who underwent OGJ with respect to American Society of Anesthesiologists (ASA) grade (I–V), age (within 10 years) and level of obstruction (pylorus, first part of duodenum D1, D2, D3 and D4). The primary outcomes compared between the groups were time to starting free oral fluids and light diet, length of stay and survival.

Results

There were no significant differences in age, sex, ASA grade and level of obstruction between the matched OGJ (n = 16), LGJ (n = 14) and ES (n = 16) groups. There was a significant reduction in time to starting free oral fluids and light diet, and length of stay after the procedure, in the ES group. Patients who underwent surgical palliation of the obstruction had significantly more complications than those who underwent stenting (P = 0·016). There were no significant differences in requirement for biliary drainage either before or after the procedure between the three groups. Survival was shortest in the ES group.

Conclusion

This matched study showed significant advantages for ES compared with OGJ and LGJ in the palliation of malignant pyloroduodenal obstruction.
Establishing a national tissue bank for surgically harvested cancer tissue
Authors: Knox K , Kerr D J
Published: January 2004

Surgeons have a part to play
Carcinoma showing thymic-like elements—a rare malignancy of the thyroid gland
Authors: Roka S , Kornek G , Schüller J , Ortmann E , Feichtinger J , Armbruster C
Published: January 2004

Background

Carcinoma showing thymic-like elements (CASTLE) is a rare tumour of the thyroid of thymic origin. The histological appearance of this tumour may be similar to that of squamous cell carcinoma of the thyroid, but outcome associated with CASTLE is more favourable.

Methods

A systematic literature review was conducted for case reports on CASTLE. A text word search of the Medline database was made with a manual search of the citations from these references. Twenty-two case reports were found.

Results

In five patients with tumour-negative lymph nodes no local or distant recurrence was observed. Seventeen patients had unknown or involved lymph nodes. Two patients were excluded from further study: one had no follow-up and one was treated by irradiation only. Of the remaining 15, six had local, three had distant and two had local and distant recurrence. In patients with involved or unknown lymph node status, local recurrence was noted in one of five patients treated by surgery and irradiation, and in seven of ten patients treated by surgery alone. Irradiation or systemic chemotherapy was given to four patients with recurrent tumours, with variable response.

Conclusion

CASTLE with tumour-negative lymph nodes has a low risk of recurrence and surgery without adjuvant therapy is sufficient. Radiotherapy seems indicated when lymph nodes are tumour positive and can be effective for recurrent tumours. In selected patients surgery for recurrent tumour can improve quality of life and outcome.