bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimization of bone growth and remodeling in response to loading in tapered mammalian limbs
Authors: Lieberman Daniel E. , Pearson Osbjorn M. , Polk John D. , Demes Brigitte , Crompton A. W. 
Published: August 2003

SUMMARYHow bones respond dynamically to mechanical loading through changes in shape and structure is poorly understood, particularly with respect to variations between bones. Structurally, cortical bones adapt in vivoto their mechanical environments primarily by modulating two processes,modeling and Haversian remodeling. Modeling, defined here as the addition of new bone, may occur in response to mechanical stimuli by altering bone shape or size through growth. Haversian remodeling is thought to be an adaptation to repair microcracks or prevent microcrack propagation. Here, we examine whether cortical bone in sheep limbs modulates periosteal modeling and Haversian remodeling to optimize strength relative to mass in hind-limb midshafts in response to moderate levels of exercise at different growth stages. Histomorphometry was used to compare rates of periosteal growth and Haversian remodeling in exercised and sedentary treatment groups of juvenile, subadult and young adult sheep. In vivo strain data were also collected for the tibia and metatarsal midshafts of juvenile sheep. The results suggest that limb bones initially optimize responses to loading according to the varying power requirements associated with adding mass at different locations. In juveniles, exercise induces higher rates of periosteal modeling in proximal midshafts and higher rates of Haversian remodeling in distal midshafts. Consequently, distal element midshafts experience higher strains and,presumably, have lower safety factors. As animals age, periosteal modeling rates decline and Haversian remodeling rates increase, but moderate levels of mechanical loading stimulate neither process significantly.
Metabolite comparisons and the identity of nutrients translocated from symbiotic algae to an animal host
Authors: Whitehead L. F. , Douglas A. E. 
Published: August 2003

SUMMARYDinoflagellate algae of the genus Symbiodinium in symbiosis with marine animals release much of their photosynthetic carbon to the animal host. The compounds translocated to the host (`mobile compounds') were investigated by metabolite comparison as follows: a substrate was identified as a candidate mobile compound when comparable profiles of metabolites were generated from host metabolism of this substrate (supplied exogenously) and the endogenous mobile compounds. When the sea anemone Anemonia viridis was incubated with NaH14CO2 under photosynthesizing conditions, most of the radioactivity in the animal tissue was recovered from the low-molecular-mass fraction and distributed in the ratio 1:2:1 between the neutral, acidic and basic sub-fractions. Prominent 14C-labelled compounds included glucose, malate and glucose-6-phosphate. When the symbiosis was incubated with 14C-labelled glucose plus succinate or fumarate(but none of eight other substrate combinations tested), the 14C-labelled metabolites closely matched those obtained with NaH14CO2. These data suggest that glucose and succinate/fumarate (or metabolically allied compounds) may be important photosynthetic compounds transferred from the Symbiodinium cells to the tissues of A. viridis. Metabolite comparisons can be applied to study nutritional interactions in symbioses involving photosynthetic algae and, with appropriate modification, other associations between microorganisms and plants or animals.
Retinoid X receptor and retinoic acid response in the marine sponge Suberites domuncula
Authors: Wiens Matthias , Batel Renato , Korzhev Michael , Müller Werner E. G. 
Published: August 2003

SUMMARY
To date no nuclear receptors have been identified or cloned from the phylogenetically oldest metazoan phylum, the Porifera (sponges). We show that retinoic acid causes tissue regression in intact individuals of the demosponge Suberites domuncula and in primmorphs, special three-dimensional cell aggregates. Primmorphs were cultivated on a galectin/poly-L-lysine matrix in order to induce canal formation. In the presence of 1 or 50 μmol l–1 retinoic acid these canals undergo regression, a process that is reversible. We also cloned the cDNA from S. domunculaencoding the retinoid X receptor (RXR), which displays the two motifs of nuclear hormone receptors, the ligand-binding and the DNA-binding domains, and performed phylogenetic analyses of this receptor. RXR expression undergoes strong upregulation in response to treatment with retinoic acid, whereas the expression of the sponge caspase is not increased. The gene encoding the LIM homeodomain protein was found to be strongly upregulated in response to retinoic acid treatment. These data indicate that the RXR and its ligand retinoic acid play a role in the control of morphogenetic events in sponges.
The effect of temperature on swimming performance and oxygen consumption in adult sockeye (Oncorhynchus nerka) and coho (O. kisutch)salmon stocks
Authors: Lee C. G. , Farrell A. P. , Lotto A. , MacNutt M. J. , Hinch S. G. , Healey M. C. 
Published: August 2003

SUMMARYOur knowledge of the swimming capabilities and metabolic rates of adult salmon, and particularly the influence of temperature on them, is extremely limited, and yet this information is critical to understanding the remarkable upstream migrations that these fish can make. To remedy this situation, we examined the effects of temperature on swimming performance and metabolic rates of 107 adult fish taken from three stocks of sockeye salmon Oncorhynchus nerka and one stock of coho salmon O. kisutchat various field and laboratory locations, using large, portable, swim tunnels. The salmon stocks were selected because of differences in their ambient water temperature (ranging from 5°C to 20°C) and the total distance of their in-river migrations (ranging from ∼100 km for coastal stocks to ∼1100 km for interior stocks). As anticipated, differences in routine metabolic rate observed among salmon stocks were largely explained by an exponential dependence on ambient water temperature. However, the relationship between water temperature and maximum oxygen consumption(ṀO2max), i.e. the ṀO2 measured at the critical swimming speed (Ucrit), revealed temperature optima for ṀO2max that were stock-specific. These temperature optima were very similar to the average ambient water temperatures for the natal stream of a given stock. Furthermore,at a comparable water temperature, the salmon stocks that experienced a long and energetically costly in-river migration were characterized by a higher ṀO2max, a higher scope for activity, a higher Ucrit and, in some cases, a higher cost of transport, relative to the coastal salmon stocks that experience a short in-river migration. We conclude that high-caliber respirometry can be performed in a field setting and that stock-specific differences in swimming performance of adult salmon may be important for understanding upstream migration energetics and abilities.
Steroids for free? No metabolic costs of elevated maternal androgen levels in the black-headed gull
Authors: Eising Corine M. , Visser G. Henk , Müller Wendt , Groothuis Ton G. G. 
Published: August 2003

SUMMARY
Within- and between-clutch variation in yolk titres of hormones of maternal origin has been found in many avian species. So far, experiments have revealed mainly beneficial effects of maternal androgens. This would also apply to black-headed gulls (Larus ridibundus). Previous experiments have shown that chicks benefit from these higher levels since their competitive abilities are improved and growth and survival probabilities thus enhanced. However, not all females show the same increase in yolk hormones from first to last egg or invest equally high amounts of androgens in their clutches. Possibly, there is a trade-off between the beneficial effects of high androgen levels and potential costs, such as increased metabolic rates. We studied possible metabolic costs of experimentally elevated yolk androgen levels for chicks of several age classes, starting three days prior to hatching until fledging at an age of approximately 30 days. Daily energy expenditure in the field, measured using the doubly labelled water technique, did not differ between treatments or between sexes. Oxygen consumption measured in birds at rest in the lab (RMR) did not vary between chicks hatched from androgen-injected (T) or oil-injected (Oil) control eggs at any age in thermo-neutral or below thermo-neutral conditions. Males showed a lower RMR than females towards the fledging age. We conclude that it is unlikely that the costs of high maternal androgen levels can be found in higher energy expenditure in the chick.
Seizure Potential of Concomitant Medications and Radiographic Contrast Media Agents
Authors: Fedutes Bethany A , Ansani Nicole T 
Published: August 2003

Objective To review seizure risk of concomitant medication administration and nonionic, water-soluble radiographic contrast media agents for myelography. Data Sources Clinical literature was identified through MEDLINE (1966–May 2003). Key search terms included metrizamide, iohexol, myelogram, myelography, seizure, and contraindications. Data Synthesis Administration of myelography contrast media can produce rare serious adverse events, including meningeal irritation, seizures, or psychological disturbances. An evaluation of case reports and clinical trials concerning seizure risks of nonionic, water-soluble radiographic myelography contrast media and concomitant medications with potential to lower the seizure threshold was performed. Conclusions Available data supporting the incidence of increased seizure risk with nonionic, water-soluble contrast media agents and concomitant medication administration that lowers the seizure threshold are anecdotal. However, because of product labeling and additive potential to decrease the seizure threshold, discontinuation of such medications should be considered to avoid the presumed increased risk of seizures.
Smart neural control of uncertain non‐linear systems
Authors: Wang Cong , Chen Guanrong , Ge Shuzhi S. 
Published: August 2003

AbstractIn this paper, we present a ‘smart’ neural control scheme for uncertain non‐linear systems using the localized radical basis function (RBF) networks. This scheme is designed such that the current control action can utilize the knowledge that the NN learned from the past control process. Compared with most existing adaptive neural controllers, which are in general very‐high‐order dynamic controllers due to the simultaneous adaptation of a large number of neural weights, the smart RBF neural controller is a static and low‐order one, and thus is more computationally feasible in practical design and implementation. To improve the generalization ability of the RBF networks, which plays an important role in the smart neural control scheme, chaotic reference signals are employed in the training phase of the scheme, where the complex chaotic signals offer richer information for NN learning due to the ergodicity of chaos. The proposed neural control scheme can act ‘smartly’ in the operational phase after the RBF networks have been well‐trained in the training phase, in a way similar to the process that humans accomplish some complicated control tasks easily after the ‘neuro‐controllers’ in their brains have been well‐trained previously. The smart neural control scheme also provides a strong motivation for the current research on chaos generation. Simulation studies are included to demonstrate the effectiveness of the new control scheme. Copyright © 2003 John Wiley & Sons, Ltd.
Sliding mode neural network control of an induction motor drive
Authors: Parma Gustavo G. , Menezes Benjamim R. , Braga Antônio P. , Costa Marcelo A. 
Published: August 2003

AbstractA new approach for induction motor drive control is presented in this paper. The new scheme is based on the direct application of an artificial neural network, trained with sliding mode control, into the feedback control system. Neural network learning is implemented with an on‐line adaptation algorithm that inherits robustness and high speed of learning from Sliding Mode Control. The results showed that proportional and integral or proportional, integral and differential controllers used in classical motor drives can be replaced with a neural network with on‐line learning. Copyright © 2003 John Wiley & Sons, Ltd.
Stable neural control of uncertain multivariable systems
Authors: Mears Mark J. , Polycarpou Marios M. 
Published: August 2003

AbstractTracking control of a class of non‐linear, uncertain, multi‐input, multiple‐output systems is addressed in this paper. The control system architecture uses neural networks for function approximation, certainty equivalent control inputs to cancel plant dynamics and smoothed sliding mode control to insure that the trajectories remain bounded. Lyapunov analysis is used to derive equations for the sliding mode control, neural network training, and to show uniform ultimate boundedness of the closed‐loop system. Stability analysis results are shown for single‐input single‐output and two‐input two‐output systems. Results are then extended to the more general multiple‐input multiple‐output case where the number of inputs is equal to the number of outputs. Simple simulation examples are used to illustrate control system performance. Copyright © 2003 John Wiley & Sons, Ltd.
Ionic Liquids, 3. Synthesis and Utilisation of Protic Imidazolium Salts in Homogeneous Catalysis
Authors: Picquet Michel , Tkatchenko Igor , Tommasi Immacolata , Wasserscheid Peter , Zimmermann Jörg 
Published: August 2003

AbstractProtonation of 1‐alkylimidazoles provides halogen‐free salts which act as ionic liquids and proton reservoir in proton‐ and metal‐assisted catalytic processes like dimerisation of methyl acrylate and ring closing metathesis, and lead to significant improvements both in activity and selectivity.
Endo‐ and Exotemplating to Create High‐Surface‐Area Inorganic Materials
Authors: Schüth Ferdi 
Published: August 2003

AbstractPorous and high‐surface‐area materials are of interest to many scientific communities. Templating pathways can be used to synthesize such materials with a high degree of control over their structural and textural properties. As templates molecular or supramolecular units are added to the synthesis mixture. They are occluded in the growing solid and leave a pore system after their removal. For such templates the term “endotemplate” is introduced. Alternatively, the templates can be materials with structural pores in which another solid is created, thus providing a scaffold for the synthesis. After removal of the scaffold, a porous or finely divided solid remains, depending on the connectivity of the template. Such a template is termed an “exotemplate”. By judicious choice of the templating procedure, unprecedented control of the structure and texture on length scales between nanometers and micrometers has been achieved over the last few years.
Study of the exfoliation process of epoxy–clay nanocomposites by different curing agents
Authors: Wang Qi , Song Chunfang , Lin Weiwei 
Published: August 2003

AbstractEpoxy–clay nanocomposites were synthesized using two organoclays cured with different chemicals at different temperatures. Interlayer distance of the clay layers and curing process were investigated by X‐ray diffraction and infrared spectra. The clay treated with facilitated curing agent, 2,4,6‐tris[(dimethylamino)methyl]phenol, can exfoliate at all curing conditions, but for the other clay treated with low‐speed curing agent, p,p′‐diaminodiphenylmethane, exfoliation of the clay layers does not occur. It was found that the relative curing speed between the interlayer and extralayer was the most important factor determining clay exfoliation. Exfoliated epoxy–clay nanocomposites can be prepared if the curing speed of the interlayer is higher than that of the extralayer, irrespective of the curing agent and temperature used. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 511–517, 2003
Growth and aging of facial soft tissues: A computerized three‐dimensional mesh diagram analysis
Authors: Ferrario Virgilio F. , Sforza Chiarella , Serrao Graziano , Ciusa Veronica , Dellavia Claudia 
Published: August 2003

AbstractThe normal growth, development, and aging of facial soft tissues was studied by three‐dimensional (3D) computerized mesh diagram analysis. The 3D coordinates of 50 soft‐tissue landmarks were collected from 591 healthy white northern Italians (351 males, 240 females) 6–40 years of age. For each gender and age class, mean values were computed, and a standardized mesh of equidistant horizontal, vertical, and anterior‐posterior lines was constructed. Within each age group, male meshes were superimposed on female meshes. For each gender, the 6‐year‐old reference mesh was superimposed on the reference mesh of each age group. The global (size plus shape) difference was evaluated by calculating the relevant displacement vectors for each landmark. Consequently, a size normalization was carried out and the shape difference was evaluated by calculating new relevant displacement vectors for each landmark. Growth and development were different along the three spatial planes: the largest increment was observed in the vertical dimension, with major modifications in the soft‐tissue profile. The vertical dimension in males increased even after 30 years of age: ear dimensions increased, trichion moved superiorly and posteriorly, and pogonion, menton, and gonion moved anteriorly and inferiorly. In all age groups, size‐standardized shape differences were found in the forehead, lower‐third facial profile, eyes, cheeks, and ears. In each age class, male dimensions were larger than female dimensions. During childhood, gender differences in size were limited; shape differences were even less manifest. Overall, the profile was more anterior and inferior, the gonia were more inferior and more lateral, the forehead was more anterior, and the ears were larger in males than in females of corresponding age. Clin. Anat. 16:420–433, 2003. © 2003 Wiley‐Liss, Inc.
Clinical importance of ligamentous and osseous structures in the cervical uncovertebral foraminal region
Authors: Yilmazlar Selcuk , Kocaeli Hasan , Uz Aysun , Tekdemir Ibrahim 
Published: August 2003

AbstractThe vertebral artery, cervical spinal nerves, spinal nerve roots, and the bony and ligamentous tissue related to the cervical vertebrae are structures whose anatomy determines the path of a surgical approach. Defining the anatomy and, in particular, determining the precise location of vulnerable structures at the intervertebral foramen and the uncovertebral foraminal region (UVFR), a region defined by the uncinate process anteriorly, the facet joint posteriorly and the foramen transversarium laterally, has critical significance when selecting the safest surgical approach. We studied the anatomy of the vertebral artery, cervical spinal nerves, and spinal nerve roots within the UVFR in six cadaver specimens. We also obtained measurements of bony structures in 35 dry cervical vertebral columns, from C3–C7. The uncinate process (UP) projects superiorly from the posterolateral aspect of each cervical vertebral body, except for the first and second vertebrae. Because the posterior part of the UP lies adjacent to the vertebral artery, spinal nerve, and spinal nerve roots, its resection creates sufficient space to decompress these structures directly. The posterolateral surface of the UP is covered by ligamentous tissue that originates from the posterior longitudinal ligament and protects the neural and vascular structures during their decompression in the UVFR. Clin. Anat. 16:404–410, 2003. © 2003 Wiley‐Liss, Inc.
Anatomical sciences in the allopathic medical school curriculum in the United States between 1967–2001
Authors: Gartner Leslie P. 
Published: August 2003

AbstractThe present article surveys the changes in the time allocated for the four disciplines in the anatomical sciences in the medical curricula of allopathic medical schools in the United States from 1967–2001. The results indicate that there was a great reduction in the laboratory portions, but not in the lecture portions of Gross Anatomy, Histology, Neuroanatomy, and Embryology. The greatest time reduction overall for the disciplines occurred between 1967–1973 (502 to 387 hr), followed by the time reduction between 1982–1995 (380 to 329 hr). Clin. Anat. 16:434–439, 2003. © 2003 Wiley‐Liss, Inc.
Workshop in clinical anatomy for residents in gynecology and obstetrics
Authors: Macchi V. , Munari P.F. , Brizzi E. , Parenti A. , De Caro R. 
Published: August 2003

AbstractA workshop in the clinical anatomy of the female pelvic viscera has been part of the training program for the first year residents in Gynecology and Obstetrics at the University of Padova since the 1999–2000 academic year. The purpose of the workshop is to offer a direct experience of practical anatomy despite a shortage of cadavers. It is designed for six residents who work in three teams on three specimens. The anatomical specimens are unembalmed, unfixed, female pelvic visceral blocs that are harvested from the cadavers 24 hr after death. They are stored at −12°C and removed from the freezer 12 hr before the workshop. The workshop is 3 hr in length and has two parts: one on theory and one practical. In the theoretical section (30 min), the teacher presents the topographical anatomy of the specimens and the residents analyze a clinically oriented worksheet. In the practical section (2 hr), the residents identify viscera, vessels, and nerves through inspection and palpation, and then a step‐by‐step dissection is carried out. In the last section (30 min), the workshop includes presentations on the three specimens that illustrate anatomical variability and assess knowledge of topographical anatomy. For many residents, this is the first practical experience of the anatomy of the female pelvic viscera because the anatomical courses for medical students do not include direct dissection by students. The unfixed viscera preserves the natural characteristics of the different tissues that exhibit the aspects of living organs, such as color, softness, and pliability, enhancing the knowledge of anatomy. The worksheet is structured as a guide to the anatomical basis of physical examination through inspection and palpation of the viscera. It also introduces the residents to the surgical anatomy of the female pelvis through a brief and selective dissection focused on the relationship between the different regional systems. Clin. Anat. 16:440–447, 2003. © 2003 Wiley‐Liss, Inc.