bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis, Structure, and Physicochemical Studies of Hexakis(2,4‐dimethylanilinium) Cyclohexaphosphate Hexahydrate
Authors: Khedhiri Lamia , Nasr Cherif Ben , Rzaigui Mohamed , Lefebre Frederic 
Published: August 2003

AbstractChemical preparation, crystal structure, thermal analysis, IR absorption, and NMR studies are given for a new organic cyclohexaphosphate, the hexakis(2,4‐dimethylanilinium) cyclohexaphosphate hexahydrate ((2,4‐Me2C6H3NH3)6P6O18⋅6 H2O). This compound crystallizes in the monoclinic space group P21/n, with cell parameters a=10.914(4) Å, b=11.198(3) Å, c=25.670(2) Å, β=95.05(4)°, Z=2, and V=3124(2) Å3. Its crystal structure is determined and refined to a final R=0.054 for 4627 independent reflections. The atomic arrangement can be described as a layer organization built by P6O18‐ring anions and H2O molecules. Between these layers are located the organic groups that form H‐bonds with O‐atoms of the P6O18 rings and H2O molecules. Determination of the geometric characteristics of the H‐bonds show the existence in this structure of four particularly strong H‐bonding contacts (1.75, 1.76, 1.78, and 1.87 Å).
N‐(4‐Biphenylmethyl)imidazoles as Potential Therapeutics for the Treatment of Prostate Cancer: Metabolic Robustness Due to Fluorine Substitution?
Authors: Leroux Frédéric , Hutschenreuter Tilman U. , Charrière Céline , Scopelliti Rosario , Hartmann Rolf W. 
Published: August 2003

Abstract3,3′,5,5′‐ And 2,2′,6,6′‐tetrafluoro‐substituted 1‐[(1,1′‐biphenyl]‐4‐yl)methyl]‐1H‐imidazoles were synthesized as inhibitors of 17α‐hydroxylase‐C17,20‐lyase (P450 17, CYP 17). P450 17 is the key enzyme of androgen biosynthesis. Its inhibition is a novel therapeutic approach for treatment of prostate cancer. To increase the so‐far insufficientin vivolifetime of such compounds, the metabolically sensitive positions were blocked by F‐substitution. Themeta‐ andortho‐F‐substituted compounds were prepared by selective metallation or halogen/metal permutation reactions performed on symmetrically substituted 1,1′‐biphenyls. Compared with the halogen‐free compounds, theortho‐F‐substituted derivatives did not match the activity, whereas themeta‐F‐substituted isomers equaled or surpassed the latter.
Synthesis of Pyrano[3,2‐b]indole Derivatives Based on Intramolecular Hetero‐DielsAlder of 2‐Benzylidene‐2,3‐dihydro‐1H‐indol‐3‐ones
Authors: Davion Yann , Joseph Benoît , Bénéteau Valérie , Léger Jean‐Michel , Jarry Christian , Mérour Jean‐Yves 
Published: August 2003

AbstractPyrano[3,2‐b]indole derivatives 2–6 were synthesized in good yields from 1‐acetyl‐2‐benzylidene‐2,3‐dihydro‐1H‐indol‐3‐ones 8 and 13–15 by an intramolecular hetero‐DielsAlder reaction. The structures of compounds 2a, 3a, 4, 5, and 6 were unambiguously established by X‐ray analysis. Compounds 4 and 5 were further aromatized to the corresponding derivatives 16 and 17, respectively.
Enantioselectivity in Odor Perception: Synthesis and Olfactory Properties of Iso‐β‐Bisabolol, a New Natural Product
Authors: Braun Norbert A. , Meier Manfred , Schmaus Gerhard , Hölscher Bernd , Pickenhagen Wilhelm 
Published: August 2003

AbstractThe odorous trace constituent iso‐β‐bisabolol (4) was isolated from East Indian and Western Australian sandalwood oil and synthesized by using the (E/Z)‐triene 12 (iso‐γ‐bisabolene) as a key intermediate. Only one of four stereoisomeric forms of 4, (6R,7R)‐4a, is odor active, having a strong floral, muguet‐like, very pleasant scent.
Multicriteria second‐order neural networks approach to imaging through turbulence
Authors: Wang Yuanmei 
Published: August 2003

AbstractAtmospheric turbulence can greatly limit the spatial resolution in optical images obtained of space objects when imaged with ground‐based telescopes. Two widely used algorithms to remove atmospheric turbulence in this class of images are blind de‐convolution and speckle imaging. Both algorithms are effective in removing atmospheric turbulence, but they use different types of prior knowledge and have different strengths and weaknesses. We have developed a multicriteria cross entropy minimization approach to imaging through atmospheric turbulence and a second‐order neural network implementations. Our simulations illustrated the efficiency of our method. © 2003 Wiley Periodicals, Inc. Int J Imaging Syst Technol 13, 146–151, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.10037
Wavelet energy spectrum for time‐frequency localization of earthquake energy
Authors: Zhou Ziqin , Adeli Hojjat 
Published: August 2003

AbstractThe authors recently developed a method for time‐frequency signal analysis of earthquake records using Mexican hat wavelets. Ground motions in earthquakes are postulated as a sequence of simple penny‐shaped ruptures at different locations along a fault line and occurring at different times. In this article, a wavelet energy spectrum is proposed for time‐frequency localization of the earthquake input energy. The ground acceleration generated by a simple penny‐shaped rupture is used as the basis to form the mother wavelet. The symmetric Mexican hat wavelet is chosen as the mother wavelet. The spectrum is presented pictorially in a two‐dimensional, time‐frequency domain. The proposed wavelet energy spectrum can be used to observe the evolution of the frequency contents of earthquake energy over time and distance of the site from the epicenter in a more accurate manner than the traditional time series (accelerogram) or frequency domain (Fourier amplitude spectrum) representation. It can be viewed as a microscope for looking into the time‐frequency characteristics of earthquake acceleration records. The wavelet energy spectrum provides frequency evolution information to be used in the structural design process. © 2003 Wiley Periodicals, Inc. Int J Imaging Syst Technol 13, 133–140, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.10038
Optimal data acquisition in fMRI using prolate spheroidal wave functions
Authors: Lindquist Martin A. 
Published: August 2003

AbstractFunctional magnetic resonance imaging (fMRI) is a technique that can be used to noninvasively study mental activity in a persons brain. fMRI has the potential to answer many interesting questions regarding the way the brain functions. Unfortunately, the drawback to fMRI studies, as they are traditionally performed, is that the temporal resolution is too low to effectively answer questions regarding what happens in an active region of the brain immediately following stimulation. Shepp and Zhang (2000) introduced a new method that could potentially lead to a significant increase in temporal resolution. Their method suggests a way to improve the time resolution in fMRI studies by sampling only a fraction of the points needed to recreate a full image. Instead of full image reconstruction, an optimal prolate spheroidal wave function filter is used to obtain a measurement over the total activity in a predefined region in the brain, B, at successive time points. The sampling region and filter are chosen in order to minimize the energy loss over the region of interest (ROI). The region they suggested to sample was chosen heuristically and corresponds to the scaled polar set of B. It was shown to be near optimal through extensive computer searches. In this article the optimal sampling region is found for the case when the ROI is circular or spherical and the sampling size is small. Based on this result, a new heuristic is introduced for other ROIs, which improves upon the results obtained using the polar set of B. © 2003 Wiley Periodicals, Inc. Int J Imaging Syst Technol 13, 126–132, 2003; Published online in Wiley Inter‐Science (www.interscience.wiley.com). DOI 10.1002/ima.10051
Fossil sister group of craniates: Predicted and found
Authors: Mallatt Jon , Chen Jun‐yuan 
Published: August 2003

AbstractThis study investigates whether the recently described Cambrian fossil Haikouella (and the very similar Yunnanozoon) throws light on the longstanding problem of the origin of craniates. In the first rigorous cladistic analysis of the relations of this animal, we took 40 anatomical characters from Haikouella and other taxa (hemichordates, tunicates, cephalochordates, conodont craniates and other craniates, plus protostomes as the outgroup) and subjected these characters to parsimony analysis. The characters included several previously unrecognized traits of Haikouella, such as upper lips resembling those of larval lampreys, the thick nature of the branchial bars, a mandibular branchial artery but no mandibular branchial bar, muscle fibers defining the myomeres, a dark fibrous sheath that defines the notochord, conclusive evidence for paired eyes, and a large hindbrain and diencephalon in the same positions as in the craniate brain. The cladistic analysis produced this tree: (protostomes, hemichordates (tunicates, (cephalochordates, (Haikouella, (conodonts + other craniates))))), with the “Haikouella + craniate” clade supported by bootstrap values that ranged from 81–96%, depending on how the analysis was structured. Thus, Haikouella is concluded to be the sister group of the craniates. Alternate hypotheses that unite Haikouella with hemichordates or cephalochordates, or consider it a basal deuterostome, received little or no support. Although it is the sister group of craniates, Haikouella is skull‐less and lacks an ear, but it does have neural‐crest derivatives in its branchial bars. Its craniate characters occur mostly in the head and pharynx; its widely spaced, robust branchial bars indicate it ventilated with branchiomeric muscles, not cilia. Despite its craniate mode of ventilation, Haikouella was not a predator but a suspension feeder, as shown by its cephalochordate‐like endostyle, and tentacles forming a screen across the mouth. Haikouella was compared to pre‐craniates predicted by recent models of craniate evolution and was found to fit these predictions closely. Specifically, it fits Northcutt and Gans' prediction that the change from ciliary to muscular ventilation preceded the change from suspension feeding to predatory feeding; it fits Butler's claim that vision was the first craniate sense to start elaborating; it is consistent with the ideas of Donoghue and others about the ancestor of conodont craniates; and, most strikingly, it resembles Mallatt's prediction of the external appearance of the ancestral craniate head. By contrast, Haikouella does not fit the widespread belief that ancestral craniates resembled hagfishes, because it has no special hagfish characters. Overall, Haikouella agrees so closely with recent predictions about pre‐craniates that we conclude that the difficult problem of craniate origins is nearly solved. J. Morphol. 258:1–31, 2003. © 2003 Wiley‐Liss, Inc.
Architectural properties of distal forelimb muscles in horses,Equus caballus
Authors: Brown Nicholas A.T. , Kawcak Christopher E. , McIlwraith C. Wayne , Pandy Marcus G. 
Published: August 2003

AbstractArticular injuries in athletic horses are associated with large forces from ground impact and from muscular contraction. To accurately and noninvasively predict muscle and joint contact forces, a detailed model of musculoskeletal geometry and muscle architecture is required. Moreover, muscle architectural data can increase our understanding of the relationship between muscle structure and function in the equine distal forelimb. Muscle architectural data were collected from seven limbs obtained from five thoroughbred and thoroughbred‐cross horses. Muscle belly rest length, tendon rest length, muscle volume, muscle fiber length, and pennation angle were measured for nine distal forelimb muscles. Physiological cross‐sectional area (PCSA) was determined from muscle volume and muscle fiber length. The superficial and deep digital flexor muscles displayed markedly different muscle volumes (227 and 656 cm3, respectively), but their PCSAs were very similar due to a significant difference in muscle fiber length (i.e., the superficial digital flexor muscle had very short fibers, while those of the deep digital flexor muscle were relatively long). The ulnaris lateralis and flexor carpi ulnaris muscles had short fibers (17.4 and 18.3 mm, respectively). These actuators were strong (peak isometric force, Fmax= 5,814 and 4,017 N, respectively) and stiff (tendon rest length to muscle fiber length, LT:LMF= 5.3 and 2.1, respectively), and are probably well adapted to stabilizing the carpus during the stance phase of gait. In contrast, the flexor carpi radialis muscle displayed long fibers (89.7 mm), low peak isometric force (Fmax= 555 N), and high stiffness (LT:LMF= 1.6). Due to its long fibers and low Fmax, flexor carpi radialis appears to be better adapted to flexion and extension of the limb during the swing phase of gait than to stabilization of the carpus during stance. Including muscle architectural parameters in a musculoskeletal model of the equine distal forelimb may lead to more realistic estimates not only of the magnitudes of muscle forces, but also of the distribution of forces among the muscles crossing any given joint. J. Morphol. 258:106–114, 2003. © 2003 Wiley‐Liss, Inc.
Differential mesowear in occluding upper and lower molars: Opening mesowear analysis for lower molars and premolars in hypsodont horses
Authors: Kaiser Thomas M. , Fortelius Mikael 
Published: August 2003

AbstractA new approach of reconstructing ungulate diet, the mesowear method, was recently introduced by Fortelius and Solounias ([2000] Am Mus Novitat 3301:1–36). Mesowear is based on facet development on the occlusal surfaces of the teeth. Restricting mesowear investigation to maxillary cheek teeth would allow mesowear investigation only in assemblages of large numbers of individuals and therefore would generally restrict this method to relatively few assemblages of recent and fossil ungulates. Most of the fossil, subfossil, and recent ungulate osteological assemblages that may be assigned to a single taxon have smaller numbers of individuals. This results in a demand to extend the mesowear method to further tooth positions in order to obtain stable dietary classifications of fossil taxa. The focus of this article is to test if a consistent mesowear classification is obtainable for mandibular as well as for maxillary teeth. For statistical testing, large assemblages of isolated cheek teeth of the Vallesian hipparionine horse Hippotherium primigenium and of the recent zebra Equus burchelli were employed as models. The upper tooth positions P4, M1, M2, and M3 as suggested by Kaiser and Solounias (2003) as the model for the “extended” mesowear method and the lower tooth positions P4–M3 were tested for their consistency in classification of the mesowear variables. We found a considerable shift of the mesowear signature towards the grazing edge of the mesowear continuum in lower cheek teeth. In order to adjust the signal of lower teeth to the signal of the upper teeth, a calibration factor was introduced which allowed incorporation of lower cheek teeth into the same model of mesowear investigation together with upper cheek teeth. We propose that this model is particularly suited for the reconstruction of paleodiets in hypsodont hipparionine and equine equids. We further investigated the functional relation between the mesowear profiles and the distribution of dental tissues along the course of the occlusal contact. We therefore correlated mesowear profiles with enamel distribution profiles and found the mesowear profile to be strongly controlled by the attritional environment encountered by a given apex area. The differential signal observed in cusp apex morphology between upper and lower cheek teeth was found to be more closely related to attrition by the antagonistic tooth than to the distribution of dental tissues in the tooth under consideration. The results suggest a general extension of the mesowear method of paleodiet reconstruction and a basic scenario for the evolution of anisodont dentitions. J. Morphol. 258:67–83, 2003. © 2003 Wiley‐Liss, Inc.
Cranial osteology in momotidae (Aves: Coraciiformes)
Authors: Pascotto Márcia C. , Donatelli Reginaldo J. 
Published: August 2003

AbstractMomotidae (motmots) is found throughout Latin America between Mexico and northern Argentina. Given the absence of detailed studies of cranial osteology of Momotidae in the literature, this article presents a comprehensive description of the variation of the cranial osteology in all nine species of Momotidae and compares the results with published studies of other families of Coraciiformes and families in other orders. In addition, the cranial structures described are related to ecological and behavioral aspects of Momotidae. The cranial osteology of Baryphthengus ruficapillus is described in detail and compared with other species of Momotidae. The results indicate the presence in Momotidae of modified cranial structures, among which the most conspicuous are the frontal, lacrimal, squamosal, orbital, and laterosphenoid regions, as well as the palatine, upper jaw, pterygoid, and mandible. J. Morphol. 258:32–48, 2003. © 2003 Wiley‐Liss, Inc.
Structural peculiarities of the tubercles in the skin of the turbot, Scophthalmus maximus (L., 1758) (Osteichthyes, Pleuronectiformes, Scophthalmidae)
Authors: Zylberberg Louise , Chanet Bruno , Wagemans France , Meunier François J. 
Published: August 2003

AbstractThe structure of the bony tubercles of the turbot, Scophthalmus maximus (L., 1758), was examined using ground sections, microradiography, SEM, and TEM. The tubercles are small, isolated, mineralized conical plates randomly distributed in the eyed side of the body. They are composed of three layers: the outer limiting layer, the external layer, and the basal plate, which make up the thin and flat elasmoid scales of Teleostei. The main difference between regular elasmoid scales and bony tubercles lies in the organization and the growth of the basal plate. Indeed, the conical shape of the tubercle is the result of a prominent thickening of the central part of the basal plate where the collagen matrix is organized in a complicated three‐dimensional network. Densely packed thick collagen fibrils form superimposed plies organized in a plywood‐like structure that resembles that of the elasmoid scales but it is criss‐crossed by numerous vertical sheets of thin collagen fibrils. The tubercles originate from thin and flat plates located in the skin of larvae and juveniles, whose structure is that of regular‐developing elasmoid scales. Thus, the tubercles of Scophthalmus maximus could be considered as modified elasmoid scales rather than bony structures. They might be the result of specific arrangements related to the general trend of reduction of the dermal skeleton in the teleostean lineage. J. Morphol. 258:84–96, 2003. © 2003 Wiley‐Liss, Inc.
Formation of cartilage in the heart of the Spanish terrapin, Mauremys leprosa (Reptilia, Chelonia)
Authors: López David , Durán Ana C. , de Andrés A. Victoria , Guerrero Alejandro , Blasco Manuel , Sans‐Coma Valentín 
Published: August 2003

AbstractCartilaginous deposits are regularly present in the heart of several reptilian, avian, and mammalian species. The formation of these extraskeletal cartilages has been studied in birds and mammals, but not in reptiles. The aim here was to elucidate this question in the Spanish terrapin. Hearts from 23 embryos belonging to Yntema (1968) developmental stages 17 to 26 and eight terrapins age 3 months to 10 years were examined using histological, histochemical, and immunohistochemical techniques. In the heart of the Spanish terrapin (Mauremys leprosa), chondrogenesis can start during embryonic life. Cartilaginous tissue develops from a mesenchymal cellular condensation that extends along the aorticopulmonary septum and the incipient pars fibrosa of the ventricular horizontal septum. This cellular condensation, which is smooth muscle α‐actin (SMα‐actin)‐negative and type II collagen‐negative during stages 17 to 22, acts as a prechondrogenic condensation. In stage 23, production of type II collagen begins in the central core of the condensation and gradually spreads toward its periphery. The type II collagen‐positive (chondrogenic) cellular condensation remains devoid of perichondrium prior to birth. Thereafter, it converts into hyaline cartilage that extends along the proximal part of the aorticopulmonary septum and the pars fibrosa of the horizontal septum. Our findings are consistent with the assumption that, as in birds and mammals, the precursors of the cardiac chondrocytes in chelonians are neural crest‐derived cells of nonmuscular nature. In addition, they point to the possibility that cells from the neural crest populate the embryonic pars fibrosa of the horizontal septum, thereby contributing to its alignment with the aorticopulmonary septum. In the present species, a second cartilaginous deposit of a hyaline nature extends along the sinus wall of the right semilunar valve of the right aorta, penetrating the fibrous cushion that constitutes the proximal support of the corresponding valve leaflet. This cartilage develops after birth, between the third and eighteenth month of life; its morphogenetic origin is unclear. The cartilaginous foci occurring in hearts of Spanish terrapin appear to act as pivots resisting mechanical tensions generated during the cardiac cycle. In the specimens examined there was no sign of replacement of the cardiac cartilages by bone tissue. J. Morphol. 258:97–105, 2003. © 2003 Wiley‐Liss, Inc.
The role of the oceans in climate
Authors: Bigg G. R. , Jickells T. D. , Liss P. S. , Osborn T. J. 
Published: August 2003

AbstractThe ocean is increasingly seen as a vital component of the climate system. It exchanges with the atmosphere large quantities of heat, water, gases, particles and momentum. It is an important part of the global redistribution of heat from tropics to polar regions keeping our planet habitable, particularly equatorward of about 30°. In this article we review recent work examining the role of the oceans in climate, focusing on research in the Third Assessment Report of the IPCC and later. We discuss the general nature of oceanic climate variability and the large role played by stochastic variability in the interaction of the atmosphere and ocean. We consider the growing evidence for biogeochemical interaction of climatic significance between ocean and atmosphere. Air–sea exchange of several radiatively important gases, in particular CO2, is a major mechanism for altering their atmospheric concentrations. Some more reactive gases, such as dimethyl sulphide, can alter cloud formation and hence albedo. Particulates containing iron and originating over land can alter ocean primary productivity and hence feedbacks to other biogeochemical exchanges. We show that not only the tropical Pacific Ocean basin can exhibit coupled ocean–atmosphere interaction, but also the tropical Atlantic and Indian Oceans. Longer lived interactions in the North Pacific and Southern Ocean (the circumpolar wave) are also reviewed. The role of the thermohaline circulation in long‐term and abrupt climatic change is examined, with the freshwater budget of the ocean being a key factor for the degree, and longevity, of change. The potential for the Mediterranean outflow to contribute to abrupt change is raised. We end by examining the probability of thermohaline changes in a future of global warming. Copyright © 2003 Royal Meteorological Society