bluuebunny/crossref_metadata_2025_split huggingface dataset:
Role of estrogen and androgen in pubertal skeletal physiology
Authors: Frank Graeme R. 
Published: July 2003

AbstractSince both estrogen and androgen are present in each sex, it has been difficult to discern the exact role that each sex steroid plays in skeletal physiology. However, studying clinical syndromes in which there is either only estrogen or androgen action has allowed us to gain insight into the unique role that each sex steroid plays in the growing skeleton. In complete androgen insensitivity syndrome (AIS) the only functional sex steroid receptor is that for estrogen. Effected XY females have a pubertal growth spurt that is typical of normal females, both in magnitude and timing. Individuals with AIS have a mild reduction in bone density but it is difficult to distinguish whether this is the result of androgen resistance or estrogen deficiency. These observations suggest that estrogen action only is sufficient to induce a normal pubertal growth spurt, epiphyseal maturation, and near normal bone mineral accretion in women. Until recently, the skeletal effects of estrogen were not thought to be of importance in the male. Conventional wisdom dictated that, in the male, testosterone mediated these skeletal changes. The notion that estrogen is of little importance in the male has been challenged by the recent discovery of two human syndromes in which estrogen action is lacking. In males with either estrogen resistance (inability to respond to circulating estrogen) or aromatase deficiency (inability to synthesize estradiol), as a result of the lack of estrogen action, a pubertal growth spurt does not appear to occur. Furthermore, complete epiphyseal maturation does not take place allowing for continued growth in adulthood and resultant tall stature. Finally normal bone mineral accretion does not take place resulting in severe osteoporosis. These findings indicate that estrogen plays a critical role in skeletal physiology of males as well as females. Med Pediatr Oncol 2003;41:217–221. © 2003 Wiley‐Liss, Inc.
Management of osteoporosis due to ovarian failure
Authors: Eastell Richard 
Published: July 2003

AbstractThe management of oestrogen deficiency bone loss needs to include general measures to protect against osteoporosis, the identification and treatment of other reversible causes of bone loss, and the use of proven agents for the treatment of osteoporosis. The general measures include improved physical activity, adequate diet (paying particular attention to calcium and vitamin D), and avoidance of behaviours that promote bone loss, such as smoking and alcohol abuse. The diseases that should be identified, other than estrogen‐deficiency, include primary hyperparathyroidism, thyrotoxicosis and celiac disease. The treatments that are proven to prevent fractures in women with estrogen deficiency, include hormone replacement therapy, raloxifene, nasal calcitonin, bisphosphonates, (alendronate and risedronate) and parathyroid hormone. The most appropriate therapy in the younger woman is HRT, although the trial‐based evidence that HRT prevents fractures is not strong. There is a wide choice of preparations and the use of continuous combined preparations avoids regular menstrual periods, one of the limitations to the use of HRT. Raloxifene has less effect on bone mineral density than HRT, but a similar effect on vertebral fractures and does not result in menstrual bleeding or increased risk of breast cancer. There is recent evidence suggesting that the beneficial effects on lipids translate into reduced risk of cardiovascular disease. Bisphosphonates are the standard treatment for the older woman with osteoporosis. Alendronate has been found to reduce the risk of spine, hip, and wrist fractures and has approval for a once weekly regimen, an approach that appears to prevent GI side effects. Risedronate reduces the risk of spine and non‐vertebral fractures within the first year of treatment and has been shown to reduce the risk of hip fracture. It has not been associated with an excess of GI side effects. Parathyroid hormone therapy results in increases in BMD that are even greater than estrogen and the bisphosphonates and to an even greater reduction in the risk of fractures, particularly non‐vertebral fractures. It works by stimulation of bone formation rather than by inhibition of bone resorption. However, it has to be given by daily injection. Thus, we have a wide choice of therapies for the woman with osteoporosis due to ovarian failure. Med Pediatr Oncol 2003;41:222–227. © 2003 Wiley‐Liss, Inc.
Regulation of bone mass by growth hormone
Authors: Olney Robert C. 
Published: July 2003

AbstractGrowth hormone (GH) is a peptide hormone secreted from the pituitary gland under the control of the hypothalamus. It has a many actions in the body, including regulating a number of metabolic pathways. Some, but not all, of its effects are mediated through insulin‐like growth factor‐I (IGF‐I). Both GH and IGF‐I play significant roles in the regulation of growth and bone metabolism and hence are regulators of bone mass. Bone mass increases steadily through childhood, peaking in the mid 20s. Subsequently, there is a slow decline that accelerates in late life. During childhood, the accumulation in bone mass is a combination of bone growth and bone remodeling. Bone remodeling is the process of new bone formation by osteoblasts and bone resorption by osteoclasts. GH directly and through IGF‐I stimulates osteoblast proliferation and activity, promoting bone formation. It also stimulates osteoclast differentiation and activity, promoting bone resorption. The result is an increase in the overall rate of bone remodeling, with a net effect of bone accumulation. The absence of GH results in a reduced rate of bone remodeling and a gradual loss of bone mineral density. Bone growth primarily occurs at the epiphyseal growth plates and is the result of the proliferation and differentiation of chondrocytes. GH has direct effects on these chondrocytes, but primarily regulates this function through IGF‐I, which stimulates the proliferation of and matrix production by these cells. GH deficiency severely limits bone growth and hence the accumulation of bone mass. GH deficiency is not an uncommon complication in oncology and has long‐term effects on bone health. Med Pediatr Oncol 2003;41:228–234. © 2003 Wiley‐Liss, Inc.
Growth hormone replacement therapy (GHRT) in children and adolescents: Skeletal impact
Authors: Mukherjee Annice , Shalet Stephen M. 
Published: July 2003

AbstractIn addition to its well‐established effects on linear growth in childhood and adolescence, growth hormone has both direct and indirect actions on bone remodelling and homeostasis. In this review the limitations of methods of assessment of bone mineral density are highlighted. The influence of growth hormone deficiency of childhood‐onset, on bone mineral accretion and, the specific skeletal implications of GHD in long‐term survivors of childhood cancers, are discussed. Specific influential factors, which affect peak bone mass achievement and therefore skeletal health in later life, are evaluated. Med Pediatr Oncol 2003;41:235–242. © 2003 Wiley‐Liss, Inc.
A general high‐order finite element formulation for shells at large strains and finite rotations
Authors: Başar Y. , Hanskötter U. , Schwab Ch. 
Published: July 2003

AbstractFor hyperelastic shells with finite rotations and large strains a p‐finite element formulation is presented accommodating general kinematic assumptions, interpolation polynomials and particularly general three‐dimensional hyperelastic constitutive laws. This goal is achieved by hierarchical, high‐order shell models. The tangent stiffness matrices for the hierarchical shell models are derived by computer algebra. Both non‐hierarchical, nodal as well as hierarchical element shape functions are admissible. Numerical experiments show the high‐order formulation to be less prone to locking effects. Copyright © 2003 John Wiley & Sons, Ltd.
An iterative defect‐correction type meshless method for acoustics
Authors: Lacroix V. , Bouillard Ph. , Villon P. 
Published: July 2003

AbstractAccurate numerical simulation of acoustic wave propagation is still an open problem, particularly for medium frequencies. We have thus formulated a new numerical method better suited to the acoustical problem: the element‐free Galerkin method (EFGM) improved by appropriate basis functions computed by a defect correction approach.One of the EFGM advantages is that the shape functions are customizable. Indeed, we can construct the basis of the approximation with terms that are suited to the problem which has to be solved. Acoustical problems, in cavities Ω with boundary T, are governed by the Helmholtz equation completed with appropriate boundary conditions. As the pressure p(x,y) is a complex variable, it can always be expressed as a function of cosθ(x,y) and sinθ(x,y) where θ(x,y) is the phase of the wave in each point (x,y). If the exact distribution θ(x,y) of the phase is known and if a meshless basis {1, cosθ(x,y), sinθ (x,y) } is used, then the exact solution of the acoustic problem can be obtained.Obviously, in real‐life cases, the distribution of the phase is unknown. The aim of our work is to resolve, as a first step, the acoustic problem by using a polynomial basis to obtain a first approximation of the pressure field p(x,y). As a second step, from p(x,y) we compute the distribution of the phase θ(x,y) and we introduce it in the meshless basis in order to compute a second approximated pressure field p(x,y). From p(x,y), a new distribution of the phase is computed in order to obtain a third approximated pressure field and so on until a convergence criterion, concerning the pressure or the phase, is obtained. So, an iterative defect‐correction type meshless method has been developed to compute the pressure field in Ω.This work will show the efficiency of this meshless method in terms of accuracy and in terms of computational time. We will also compare the performance of this method with the classical finite element method. Copyright © 2003 John Wiley & Sons, Ltd.
Computational design of swarms
Authors: Zohdi T. I. 
Published: July 2003

AbstractIn this work, a method for the rapid computational design and simulation of multiparticle swarms is developed. Specifically, a non‐convex optimization strategy is constructed, based on genetic algorithms, to design desired swarm‐like behaviour. To allow rapid evaluation of various swarm design performances, a temporally‐adaptive iterative scheme is developed to determine the positions, velocities and accelerations of members of the swarm. The overall purpose of such an approach is to facilitate rapid decision making for the dynamics of large numbers of interacting objects, whose goal is to reach a target guarded by obstacles in a minimum amount of time. Copyright © 2003 John Wiley & Sons, Ltd.
Cn continuous modelling of smooth contact surfaces using NURBS and application to 2D problems
Authors: Stadler M. , Holzapfel G. A. , Korelc J. 
Published: July 2003

AbstractThis paper presents a strategy for the finite element implementation of Cn continuous contact surfaces for deformable bodies undergoing finite deformations, whereby n represents an arbitrary level of continuity. The proposed novel approach avoids the non‐physical oscillations of contact forces which are induced by the traditional enforcement of kinematic contact constraints via faceted surfaces discretizing the interacting boundaries. In particular, for certain problems, the level of continuity may influence the rate of convergence significantly within a non‐linear solution scheme. A hierarchical tree data structure is proposed for an efficient search algorithm to find the neighbour elements on adaptively refined meshes, which are involved in the smoothing process of a particular finite element. The same data structure is used for the automatic detection of the contact surfaces of a body. Three representative numerical examples demonstrate the increased rate of convergence, the ability to trace the actual surface more accurately and the prevention of pressure jumps of the proposed method. Copyright © 2003 John Wiley & Sons, Ltd.
New crack‐tip elements for XFEM and applications to cohesive cracks
Authors: Zi Goangseup , Belytschko Ted 
Published: July 2003

AbstractAn extended finite element method scheme for a static cohesive crack is developed with a new formulation for elements containing crack tips. This method can treat arbitrary cracks independent of the mesh and crack growth without remeshing. All cracked elements are enriched by the sign function so that no blending of the local partition of unity is required. This method is able to treat the entire crack with only one type of enrichment function, including the elements containing the crack tip. This scheme is applied to linear 3‐node triangular elements and quadratic 6‐node triangular elements. To ensure smooth crack closing of the cohesive crack, the stress projection normal to the crack tip is imposed to be equal to the material strength. The equilibrium equation and the traction condition are solved by the Newton–Raphson method to obtain the nodal displacements and the external load simultaneously. The results obtained by the new extended finite element method are compared to reference solutions and show excellent agreement. Copyright © 2003 John Wiley & Sons, Ltd.
Qualitative and quantitative determination of yohimbine in authentic yohimbe bark and in commercial aphrodisiacs by HPLC‐UV‐API/MS methods
Authors: Zanolari Boris , Ndjoko Karine , Ioset Jean‐Robert , Marston Andrew , Hostettmann Kurt 
Published: July 2003

AbstractThe development and validation of a rapid qualitative and quantitative method based on an HPLC‐UV‐MS technique with atmospheric pressure chemical ionisation and electrospray ionisation for the analysis of yohimbine in a number of commercial aphrodisiac products is reported. HPLC with multiple‐stage mass spectrometry experiments allowed the identification of the target compound and increased the selectivity of complex analyses such as those involved with multi‐botanical preparations. The precision and the robustness of the method were improved by the use of two internal standards: codeine for UV detection and deuterium‐labelled yohimbine for MS detection. Twenty commercial aphrodisiac preparations were analysed and the amount of yohimbine measured and expressed as the maximal dose per day suggested on product labels ranged from 1.32 to 23.16 mg. Copyright © 2003 John Wiley & Sons, Ltd.
Isolation of high‐quality RNA from white spruce tissue using a three‐stage purification method and subsequent cloning of a transcript from the PR‐10 gene family
Authors: Mattheus Nathalie , Ekramoddoullah Abul K. M. , Lee Stephen P. 
Published: July 2003

AbstractIsolation of PinmIII cDNA homologues from white spruce tissues required a rigorous RNA extraction protocol developed following assessment of three previously reported conifer RNA extraction protocols. Total RNA was extracted via several purification steps designed to minimize binding of phenolics to nucleic acids and was then subjected to caesium chloride ultra‐centrifugation. This procedure produced consistently high‐quality, intact RNA from both needles and roots with spectrophotometric ratios of approximately 2.0 for both 260/280 nm and 260/230 nm. Total RNA was obtained from the roots of cold‐hardened white spruce seedlings for cDNA library construction. More than 2 million recombinant phage particles were generated from 5 µg of a poly(A)+RNA fraction, and ca. 1.3 million cDNA particles were amplified for storage. Approximately 500,000 primary recombinant clones were screened with an heterologous PinmIII cDNA sequence yielding a unique clone, picg1, that was very similar to members of the PR10 gene family. Copyright © 2003 John Wiley & Sons, Ltd.
Chemiluminescence inhibition assay for folic acid using flow injection analysis
Authors: Song Zhenghua , Wang Lin 
Published: July 2003

AbstractA new flow injection method for the determination of folic acid is described. A fast oxidation reaction occurred when folic acid was mixed with potassium ferricyanide generating ferrocyanide which then inhibited the chemiluminescent reaction of ferricyanide and luminol in alkaline medium. The decrease of chemiluminescence intensity was correlated with the folic acid concentration in the range 0.1–21 µg/mL; the detection limit for the assay was 0.03 µg/mL (3σ). A complete analysis of folic acid, including sampling and washing, could be performed within 2 min with a relative standard deviation of less than 4.0%. The proposed method has been applied successfully to the determination of folic acid in pharmaceutical preparations Copyright © 2003 John Wiley & Sons, Ltd.
Fractionation of grape tannins and analysis by matrix‐assisted laser desorption/ionisation time‐of‐flight mass spectrometry
Authors: Perret Camille , Pezet Roger , Tabacchi Raphael 
Published: July 2003

AbstractPolymeric tannins, extracted from grape berries (Gamay variety), were fractionated according to their mean degree of polymerisation (mDP) on a styrene–divinylbenzene phase eluted with a gradient of methanol:chloroform. Increasing the percentage of methanol led to the solubilisation of higher molecular weight tannins. The mean mDP of each collected fraction was determined by acid‐catalysed degradation in the presence of a nucleophilic reagent. The fractionation method produced a linear gradient of mDP varying between 1.84 and 19.34. The fractions were partially characterised by matrix assisted laser desorption/ionisation time‐of‐flight mass spectrometry (MALDI‐TOF/MS). The spectra showed a complex mixture of proanthocyanidins and galloylated proanthocyanidins up to 4000 amu. Copyright © 2003 John Wiley & Sons, Ltd.
Supercritical fluid extraction of naringin from the peel of Citrus paradisi
Authors: Giannuzzo Amelia N. , Boggetti Héctor J. , Nazareno Mónica A. , Mishima Horacio T. 
Published: July 2003

AbstractThe highest yield (14.4 g/kg) of naringin, the major flavonoid from the peel of Citrus paradisi L., that could be achieved by supercritical fluid extraction was obtained using supercritical carbon dioxide modified with 15% ethanol and fresh (rather than dried) peels at 95 bar and 58.6°C. This yield is higher than that attained by the conventional technique of maceration, and close to those obtained by reflux and Soxhlet methods. Furthermore, supercritical fluid extraction consumes less solvent and provides a shorter extraction time than conventional extraction methods. Copyright © 2003 John Wiley & Sons, Ltd.
A simple differential pulse polarographic method for the determination of thymoquinone in black seed oil
Authors: Michelitsch Astrid , Rittmannsberger Anna 
Published: July 2003

AbstractA reliable and simple differential pulse polarographic method is described for the determination of thymoquinone in black seed oil. The polarographic behaviour of thymoquinone was examined in various buffer systems over the pH range 5.0–10.0. Thymoquinone is reduced in a single, reversible peak at the dropping mercury electrode. The differential pulse polarogram showed a distinct peak in Sörensen buffer:methanol (3:7, v/v; pH 8.5) at a peak potential of −0.095 V (vs. silver/silver chloride electrode), and a plot of peak height against concentration was found to be linear over the range 0.2–15.0 µg/mL (R = 0.9998). The limit of detection was calculated to be 0.054 µg/mL. The polarographic method has been applied to determine thymoquinone in two black seed oil preparations available on the Austrian pharmaceutical market. Copyright © 2003 John Wiley & Sons, Ltd.
Chemical polymorphism of the essential oils from populations of Thymus caespititius grown on the islands Pico, Faial and Graciosa (Azores)
Authors: Pereira S. I. , Santos P. A. G. , Barroso J. G. , Figueiredo A. C. , Pedro L. G. , Salgueiro L. R. , Deans S. G. , Scheffer J. J. C. 
Published: July 2003

AbstractThe compositions of the essential oils isolated from the aerial parts of 11 populations of Thymus caespititius collected during the ﬂowering phase on Pico, Faial and Graciosa (Azores) were studied by GC and GC‐MS. The monoterpene fraction was dominant in all the oils analysed (55–90%) and consisted mainly of oxygen‐containing compounds (44–79%). Sesquiterpenes represented an important fraction of the oils from the populations grown on Graciosa (13–28%). In contrast, this fraction was rather small in the oils from the populations grown on Pico and Faial (6–11%). Despite this, oxygen‐containing compounds (4–18%) were always dominant. Cluster analysis of all identiﬁed oil components grouped the oils into three main clusters that corresponded with their main components. The oils from the 11 populations studied showed a clear chemical polymorphism that, in some cases, was more evident among populations growing on the same island than among those from different islands. Copyright © 2003 John Wiley & Sons, Ltd.
Monitoring seasonal variation in apple fruit volatile emissions in situ using solid‐phase microextraction
Authors: Hern Alan , Dorn Silvia 
Published: July 2003

AbstractEmissions of volatiles from apple fruits (Malus domestica Borkh.) were monitored in situ over the course of a growing season (from early June to mid September) for two apple varieties, Golden Delicious and Maigold. Results indicate a characteristic time‐course of volatile emissions as the sampling date was a statistically signiﬁcant factor for nine of the 13 compounds considered. The amounts of volatiles collected were greatest early and late in the season. The temporal effect on emissions was generally much larger than the effect of variety, which was signiﬁcant for only four of the 13 compounds considered. The possible sources of variation which are not explained by the statistical models are discussed, and it is considered that they are most likely related to differences in the emissions from individual fruits. Copyright © 2003 John Wiley & Sons, Ltd.
Enantiomeric differentiation of bornyl acetate by 13C‐NMR using a chiral lanthanide shift reagent
Authors: Baldovini Nicolas , Tomi Félix , Casanova Joseph 
Published: July 2003

AbstractThe enantiomeric differentiation of bornyl acetate was carried out by 13C‐NMR spectroscopy using a chiral lanthanide shift reagent. The technique was successfully applied to the determination of the enantiomer of bornyl acetate present in the essential oil of Inula graveolens. Copyright © 2003 John Wiley & Sons, Ltd.
Seasonal variability of phytoplankton at Varna Bay (Black Sea)
Authors: Moncheva Snejana , Gorinstein Shela , Shtereva Galina , Toledo Fernando , Arancibia Patricia , Booth William A. , Goshev Ivan , Weisz Moshe , Trakhtenberg Simon 
Published: July 2003

AbstractIntrinsic ﬂuorescence and SDS‐PAGE analysis were employed to study the seasonal qualitative and quantitative changes of phytoplankton composition at Varna Bay (Black Sea). Variation in the maximum emission wavelength (λmax) of the phytoplankton proteins (398 nm in the summer and 340 nm in the spring) was observed. In addition, a decrease in ﬂuorescence intensity, and a shift in λmax as a result of changes in phytoplankton protein stability, according to the season, was noted. Similarly, SDS‐PAGE analysis showed different protein patterns for each season, for example in summertime the major protein constituents were of 14, 37, 48 and 70 kDa, while in the springtime the sizes ranged between 38 and 48 kDa. In general, higher carbohydrate and protein contents correlated with larger phytoplankton biomass found during the summer. The dominant species, the Bacillariophyceae and Dinophyceae, were found to be present in the water body in an alternate pattern. All of these changes could be accounted for by the adaptation of the organism to seasonal variations that modify the sea environment at Varna Bay. Copyright © 2003 John Wiley & Sons, Ltd.