bluuebunny/crossref_metadata_2025_split huggingface dataset:
Large molecules as anti-adhesive compounds against pathogens
Authors: Wittschier N , Lengsfeld C , Vorthems S , Stratmann U , Ernst J F , Verspohl E J , Hensel A 
Published: July 2007

Abstract
Anti-adhesive compounds are potential prophylactic tools in alternative treatment regimes against bacterial infection, as bacterial adhesion is commonly mediated by carbohydrate-protein interactions between surface adhesions of microorganisms and the host cell. The use of exogenous polyvalent, high-molecular carbohydrates and tannin-like plant-derived compounds should antagonize the adhesive interaction. A range of carbohydrates and carbohydrate- and proanthocyanidin-enriched plant extracts were screened for potential anti-adhesive effects against Helicobacter pylori, Campylobacter jejuni, Porphyromonas gingivalis and Candida albicans in different in-situ assays on primary tissue. The adhesion of H. pylori on human stomach tissue was effectively blocked by glucuronic acid-enriched polysaccharides from immature okra fruits (Abelmoschus esculentus). These compounds also had strong in-vitro effects against C. jejuni (inhibition up to 80%), but were ineffective in an in-vivo study in infected chicken broilers due to metabolism in the gastrointestinal system. Polysaccharides from Glycyrrhizia glabra, also enriched with glucuronic acid, showed strong anti-adhesive properties against H. pylori and P. gingivalis (inhibition 60–70%). Pelargonium sidoides extract, containing mainly polymeric proanthocyanidins, was effective against H. pylori in a dose-dependent manner. Due to the multifunctional adhesive strategy of C. albicans, no effective compounds were detected against this yeast. Structure-activity relationships are presented and the potential in-vivo use of carbohydrate-based anti-adhesives is discussed.
Pharmacokinetics of letrozole in male and female rats: influence of complexation with hydroxybutenyl-β-cyclodextrin
Authors: Wempe Michael F , Buchanan Charles M , Buchanan Norma L , Edgar Kevin J , Hanley Gregory A , Ramsey Michael G , Skotty Jennifer S , Rice Peter J 
Published: July 2007

Abstract
Cyclodextrins (CDs) are one of the most successful solutions to the problem of poor drug solubility. In this study, we examined the in-vitro effects of three CDs on the solubility of letrozole, a breast cancer drug that is practically insoluble in water. The most promising, hydroxybutenyl-β-cyclodextrin (HBenβCD), was used for in-vivo studies in male and female Sprague-Dawley rats. Letrozole is a drug with dramatic gender-based differences in pharmacokinetics. For example, the terminal half-life (t1/2) of letrozole following intravenous administration in male rats was 11.5 ± 1.8 h (n = 3), while in female rats it was 42.3 ± 2.9 h (n = 3). HBenβCD increased the solubility and enhanced the dissolution rate of letrozole. Complexation of letrozole with HBenβCD improved oral absorption in male rats and maximized absorption in female rats. Regardless of gender, the presence of HBenβCD in the formulation increased the in-vivo rate of absorption. When administered in a capsule formulation with letrozole, HBenβCD resulted in a higher Cmax (61% in male rats, 42% in female), shorter Tmax values (8.4 to 6.3 h in male, 16.4 h to 5.4 h in female) and increased absolute oral bioavailability (46 ± 2 vs 38 ± 3 in male, 101 ± 3 vs 95 ± 2 in female). Thus, solubility limits both rate and extent of letrozole absorption in male rats, but limits only the rate of absorption in female rats.
Prediction of human pharmacokinetics—evaluation of methods for prediction of hepatic metabolic clearance
Authors: Fagerholm Urban 
Published: July 2007

AbstractMethods for prediction of hepatic clearance (CLH) in man have been evaluated. A physiologically-based in-vitro to in-vivo (PB-IVIV) method with human unbound fraction in blood (fu,bl) and hepatocyte intrinsic clearance (CLint)-data has a good rationale and appears to give the best predictions (maximum ∼2-fold errors; &lt; 25% errors for half of CL-predictions; appropriate ranking). Inclusion of an empirical scaling factor is, however, needed, and reasons include the use of cryopreserved hepatocytes with low activity, and inappropriate CLint- and fu,bl-estimation methods. Thus, an improvement of this methodology is possible and required. Neglect of fu,bl or incorporation of incubation binding does not seem appropriate. When microsome CLint-data are used with this approach, the CLH is underpredicted by 5- to 9-fold on average, and a 106-fold underprediction (attrition potential) has been observed. The poor performance could probably be related to permeation, binding and low metabolic activity. Inclusion of scaling factors and neglect of fu,bl for basic and neutral compounds improve microsome predictions. The performance is, however, still not satisfactory. Allometry incorrectly assumes that the determinants for CLH relate to body weight and overpredicts human liver blood flow rate. Consequently, allometric methods have poor predictability. Simple allometry has an average overprediction potential, &gt; 2-fold errors for ∼1/3 of predictions, and 140-fold underprediction to 5800-fold overprediction (potential safety risk) range. In-silico methodologies are available, but these need further development. Acceptable prediction errors for compounds with low and high CLH should be ∼50 and ∼10%, respectively. In conclusion, it is recommended that PB-IVIV with human hepatocyte CLint and fu,bl is applied and improved, limits for acceptable errors are decreased, and that animal CLH-studies and allometry are avoided.
Montelukast reduces ischaemia/reperfusion-induced bladder dysfunction and oxidant damage in the rat
Authors: Şener Göksel , Şehirli Ozer , Toklu Hale , Ercan Feriha , Alican Inci 
Published: July 2007

Abstract
The present study aimed to investigate the possible beneficial effects of the cysteinyl leukotriene-1 receptor antagonist montelukast on contractility and oxidant damage after ischaemia/reperfusion (I/R) of rat urinary bladder. The abdominal aorta of Sprague-Dawley rats was occluded to induce I/R. Montelukast (10 mg kg−1) or saline was administered intraperitoneally before I/R. In the sham-operated group, the abdominal aorta was left intact and the animals were treated with montelukast or saline. After decapitation, the bladder was removed and the tissue was either used for functional studies or stored for biochemical assays. In the I/R group, the isometric contractile responses of the bladder strips to carbachol (10−8-10−4 M) were lower than those of the control group and were reversed by treatment with montelukast. Lipid peroxidation and myeloperoxidase activity of the bladder tissues in the I/R group were greater than in the sham-operated group. Montelukast treatment in the I/R group decreased these parameters compared with I/R alone. Similarly, the significant decrease in tissue glutathione level in the I/R group compared with controls was also prevented by montelukast. Treatment with montelukast almost completely reversed the low contractile responses of rat urinary bladder to carbachol and prevented oxidative tissue damage following I/R.
Decursinol and decursin protect primary cultured rat cortical cells from glutamate-induced neurotoxicity
Authors: Kang So Young , Kim Young Choong 
Published: July 2007

Abstract
We previously reported six neuroprotective decursinol derivatives, coumarins from Angelica gigas (Umbelliferae) roots. To elucidate the action patterns of decursinol derivatives, we investigated the neuroprotective effects of decursinol and decursin, which showed highly significant activity and were major constituents of A. gigas, using primary cultures of rat cortical cells in-vitro. At concentrations of 0.1–10.0 μM, both decursinol and decursin exerted a significant neuroprotective activity pretreatment and throughout treatment. In addition, decursin had a neuroprotective impact in the post-treatment paradigm implying that decursin might possess different action mechanisms from that of decursinol in the protection of neurons against glutamate injury. Both decursinol and decursin effectively reduced the glutamate-induced increased intracellular calcium ([Ca2+]i) in cortical cells, suggesting that these two coumarins may exert neuroprotection by reducing calcium influx by overactivation of glutamate receptors. This suggestion was supported by the result that decursinol and decursin protected neurons against kainic acid (KA)-induced neurotoxicity better than against that induced by N-methyl-D-aspartate (NMDA). Moreover, both decursinol and decursin significantly prevented glutamate-induced decreases in glutathione, a cellular antioxidant, and glutathione peroxidase activity. In addition, both compounds efficiently reduced the overproduction of cellular peroxide in glutamate-injured cortical cells. These results suggested that both decursinol and decursin protected primary cultured rat cortical cells against glutamate-induced oxidative stress by both reducing calcium influx and acting on the cellular antioxidative defence system. Moreover, decursin is considered to probably have a different action mechanism from that of decursinol in protecting cortical cells against glutamate injury.
An extract of Apium graveolens var. dulce leaves: structure of the major constituent, apiin, and its anti-inflammatory properties
Authors: Mencherini T , Cau A , Bianco G , Loggia R Della , Aquino R P , Autore G 
Published: July 2007

Abstract
Flavonoids, natural compounds widely distributed in the plant kingdom, are reported to affect the inflammatory process and to possess anti-inflammatory as well as immunomodulatory activity in-vitro and in-vivo. Since nitric oxide (NO) produced by inducible nitric oxide synthase (iNOS) is one of the inflammatory mediators, the effects of the ethanol/water (1:1) extract of the leaves of Apium graveolens var. dulce (celery) on iNOS expression and NO production in the J774.A1 macrophage cell line stimulated for 24 h with Escherichia coli lipopolysaccharide (LPS) were evaluated. The extract of A. graveolens var. dulce contained apiin as the major constituent (1.12%, w/w, of the extract). The extract and apiin showed significant inhibitory activity on nitrite (NO) production in-vitro (IC50 0.073 and 0.08 mg mL−1 for the extract and apiin, respectively) and iNOS expression (IC50 0.095 and 0.049 mg mL−1 for the extract and apiin, respectively) in LPS-activated J774.A1 cells. The croton-oil ear test on mice showed that the extract exerted anti-inflammatory activity in-vivo (ID50 730 μg cm−2), with a potency seven-times lower than that of indometacin (ID50 93 μg cm−2), the non-steroidal anti-inflammatory drug used as reference. Our results clearly indicated the inhibitory activity of the extract and apiin in-vitro on iNOS expression and nitrite production when added before LPS stimulation in the medium of J774.A1 cells. The anti-inflammatory properties of the extract demonstrated in-vivo might have been due to reduction of iNOS enzyme expression.
The effect of Poisson's ratio on stress concentrations
Authors: Grant R J , Lorenzo M , Smart J 
Published: July 2007

In design, it is common to use values for stress concentration factors (SCFs) obtained from textbooks. These textbook values have generally been obtained from photoelastic experiments for which Poisson's ratio will probably have a value greater than 0.3 and for frozen stress analysis a value approaching 0.5. However, when designing machine parts made from other isotropic materials, e.g. metals and structural ceramics, Poisson's ratio will probably have a lower value, which will affect the value of the SCF. In this paper, various stress-raising features have been analysed using the finite element method to determine the stress concentration factor. It is shown that Poisson's ratio can have a significant effect on the SCF.
Residual stresses in rolled and machined nickel alloy plates: Synchrotron X-ray diffraction measurement and three-dimensional eigenstrain analysis
Authors: Korsunsky A. M , Regino G. M , Latham D. P , Li H. Y , Walsh M. J 
Published: July 2007

Most engineering components made from wrought metallic alloys undergo complex sequences of manufacturing operations. These processing steps frequently include extrusion, forging, or rolling, followed by machining and heat treatment. Since such components will be subjected to service loading as part of engineering assemblies, their durability must be assessed using suitably reliable life prediction models. The present study is aimed at the investigation of a combination of experimental and modelling techniques that involves microstructural investigation, diffraction measurement of residual elastic strains, and finite element simulation of residual stress distributions. Eigenstrain-based modelling approach to the analysis of processing-induced residual stresses has been previously presented in the two-dimensional approximation, i.e. under the assumption that the equivalent permanent plastic strain field induced by processing is equibiaxial. Several different formulations were considered and compared, including plane stress, plane stress, and three-dimensional models. In the present study a further development of the eigenstrain-based analysis approach that incorporates the experimental data obtained from synchrotron X-ray diffraction measurements of residual elastic strains in two complementary cross-sections of a forged and machined nickel superalloy plate is reported. The microstructure was assessed using electron backscattered diffraction, and near-surface residual stresses evaluated using laboratory X-ray diffraction. It is found that the results of fully three-dimensional formulation differ from two-dimensional approximations particularly in the vicinity of machined surfaces, having potentially significant implications for durability assessment and fatigue life models.
The rotating wedge: A method of obtaining strain-free locations in a centrifugal field
Authors: Macduff I. B. 
Published: July 2007

In strain measurement on rotating members using electrical resistance strain gauges and slip rings, difficulties associated with slip ring ‘noise’ may be overcome by several means, one of which is to adopt the full rotating bridge. As well as the active, the three inactive gauges of the bridge are mounted on the rotating side, the compensator preferably at a strain-free location. Investigators have adopted several methods of achieving this. A new method has been devised whereby the inactive gauges are mounted axially on the segmented circumference of a thin disc of the same material as the test member, rotating with it on the same axis. Axial slots, running in depth radially into the disc, divide the circumference into a large number of small segments or ‘teeth’, each of which is virtually the wide end of a narrow rotating wedge. Experimental evidence has been examined, demonstrating that the only significant stress in the narrow rotating wedge is radial stress. The theoretical solution for the stresses is therefore of the form of Boussinesq's two-dimensional elasticity solution for the stationary wedge symmetrically loaded at the apex. The solution for the narrow rotating wedge has been indicated on this basis. Subsequent to tests to determine the strain equivalent to slip ring noise in a new commercially produced slip ring unit, an investigation using strain gauges was carried out to verify that the segment locations of a 10 in overall diameter rotating aluminium segmented disc were strain-free to a speed of 2400 rev/min. The geometry of the segmented disc has been considered in respect of notch depth, nominal circumferential stresses in the body of the rotating disc and stress concentration at the notch roots. Other means of producing the necessary strain-free ‘platforms’ have been suggested for circumstances in which material is unavailable for manufacture of a segmented disc. An arrangement of test member, segmented disc and strain gauge circuit has been adopted for a steady-state centrifugal strain investigation on a water turbine.
The unstable behaviour of thin-walled unsymmetrical section beams subjected to combined bending and torsion
Authors: Black M. M. 
Published: July 2007

The investigation described in this paper examines the large displacement behaviour of thin-walled un-symmetrical section beams subjected to combined bending and torsion. The relevant theory is briefly described and a method of theoretical solution is given. The unstable nature of the behaviour is indicated and the requirements and design of a suitable experimental test rig used to verify the theoretical results are discussed. Typical experimental results are shown and compared with the corresponding theoretical values.
Low endurance fatigue behaviour of mild steel beams in reversed bending
Authors: Royles R 
Published: July 2007

The behaviour of mild steel under conditions of reversed bending in the inelastic range at relatively slow rates of cycling, falls into the category of the low endurance fatigue problem in metals, where failures occur within 105 cycles. This investigation is concerned with an examination of material behaviour in reversed bending (i.e. pure bending) at three frequencies——1, 10 and 100 c/min——and strain ranges in the region from 0.5-12 per cent. Axial extension assumed some significance during the tests at the larger strain ranges, as did cyclic heating at the higher frequency. Some adjustments are made to take account of the effects of axial extension in the tests at the two lower frequencies. A moment-curvature relationship for the material in a cyclic state is established along with a fatigue resistance law for the range of deformations considered; the former being restricted to cyclic operations in the range from 1 to 10 c/min. An indication is given, supported by some experimental evidence, of how the moment-curvature relationship and fatigue resistance law can be used to predict the behaviour of mild steel structural components subjected to the type of loading under consideration.
A theoretical study of in-plane bending of a single unreinforced mitred-bend
Authors: Jones N , Kitching R 
Published: July 2007

It can be shown that an exact analysis of the deformations or stresses in a single mitred-bend would involve some terms which rapidly decay along the pipe axes and others which would have a relatively long damping length. The overall flexibility and radial deformations of a single unreinforced mitred-bend have been estimated by minimizing the strain energy contributed by the long damping length terms in a manner similar to that used by von Kármán for curved pipe-bends. Finally, the short damping length terms are introduced in order to satisfy the equilibrium and compatibility conditions across the oblique intersection of the two pipes forming the mitred-bend. The theoretical values of overall flexibility, diameter changes, and stresses were found to be in close agreement with experimental values for a single right-angled unreinforced mitred-bend.
Design implications of tests on a large 90° smooth bend
Authors: Poynor J F 
Published: July 2007

The paper details the design implications of a site strain gauge test carried out on the 6 ft 6 in diameter reactor outlet ducting of a nuclear power station. The test subjected a portion of the ducting to a horizontal load of 10 ton, and the strain gauge survey was taken on a smooth bend of the ducting which was inherently flexible and did not incorporate the usual bellows units to absorb thermal expansions. Theoretical stresses in the bend of the test portion were calculated under the horizontal load, and comparison made between experimental and theoretical values. At the design stage of the station a detailed analysis was carried out for the complete system under thermal expansions, and this analysis is briefly described. Using the comparison obtained from the test portion, an estimate is made of the probable stress levels that will exist in the complete duct system under reactor operating conditions. During fabrication of the smooth bends a dimensional survey was carried out on a complete component, and the tolerances achieved are discussed and compared with tolerances obtained on the more usual smaller diameter welding elbow. The effect of end restraints on the flexibility of smooth bends is also discussed, and the lack of design information on this aspect is emphasized. It is concluded that the stresses in the bends may be accurately predicted, but a larger error is likely to occur in the prediction of end reactions and the stresses induced in vessels subjected to these reactions.
The application of moiré rotational mismatch techniques to strain analysis
Authors: Vafiadakis A P , Lamble J H 
Published: July 2007

Theoretical and technological aspects of moiré fringe techniques when applied to problems of strain analysis are discussed. An outline is given of the methods of determination of direct and shear strain distributions of elastic and plastic orders of magnitude from the formation of moiré patterns resulting from the superposition of two gratings of straight parallel lines. The rotational mismatch technique is discussed and shown to give strain directly. Reference is made to the use of master gratings, to the ‘photo-resist’ and ‘stripping film’ techniques for the reproduction of these gratings and to some of the photographic difficulties encountered. The advantages of the moiré techniques over conventional methods of strain evaluation employing extensometers, strain gauges and photoelastic materials are discussed and illustrated by results obtained during (1) uni-axial tensile tests on mild steel, brass and aluminium alloy, and (2) diametral compressive tests on cast iron discs.
Low cycle fatigue of steels under biaxial straining
Authors: Pascoe K J , de Villiers J W R 
Published: July 2007

A cruciform test specimen and a loading rig are described, by which any combination of biaxial strains can be applied to a specimen. With the pressurizing equipment so far available, three states of strains have been investigated for two steels. In the mild steel used, large inclusions oriented in the roll direction aided fracture propagation when a maximum shear plane coincided with the roll direction. When not influenced by inclusions, fatigue life is related to total strain range by Coffin's law ∊ N a = C The values of α and C are different for different states of strains. Empirical formulae are given to predict results for other states of strains.
Creep buckling of columns with lateral restraint
Authors: Freed N H , Alexander J M 
Published: July 2007

This problem arises from the use of vertical fuel elements in graphite-moderated types of nuclear reactor. Previous theoretical work based on the tangent rate modulus approach has been extended to cover all phases of creep and elastic deformation for both symmetric and asymmetric single-plane bowing. By introducing a ‘solution time’ parameter, a generalized solution can be derived for any given material and initial shape, which is valid for an arbitrary range of sizes of rod, temperatures, and loads (neglecting elasticity). For ‘Magnox’ at 295°C the theory indicates that elastic deformation is negligible. It was found from experiments on round ‘Magnox’ rods which were allowed to ‘lay’ against a simulated channel wall (this is the condition described as continuous lateral restraint) that creep bowing seldom occurred in a single plane. Comparison with the theoretical analysis for such cases was therefore difficult, but it was found that the theoretical predictions were generally very conservative, and that by splitting the measured deflections into major and minor planes some correlation could be obtained. By using a specimen of rectangular crosssection having an aspect ratio of 2:1, bowing was confined to a single plane and very good agreement with the theory was obtained, both with respect to the deflected shape itself and to the time required to achieve it.