bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of microcrystallinity and morphology on physical aging of poly(ethylene terephthalate)
Authors: Zhou Hongxia , Lofgren Elizabeth A. , Jabarin Saleh A.
Published: August 2007

Physical aging characteristics of poly(ethylene terephthalate) have been evaluated in relationship to volume fraction levels of crystallinity up to 25%. Changes in the enthalpies of relaxation, monitored at aging temperatures from 55 to 65°C, are found to give good fits with the Cowie‐Ferguson model. Overall equilibrium enthalpy of relaxation values decrease linearly with increased crystallinity. They increase with decreased aging temperature, providing extrapolated lower temperature results that are validated in terms of specific heat relationships. Activation energies for enthalpic relaxations are found to increase from 337 to 361 kJ/mole as crystallinity increases up to 25%. Overall relaxation endotherms are further resolved into contributions from interspherulitic and intraspherulitic amorphous regions. Interspherulitic, equilibrium enthalpies of relaxation decrease with increased levels of crystallinity, while intraspherulic values show corresponding increases. Characteristic relaxation times of the intraspherulic regions increase greatly, as levels of crystallinity increase; however, interspherulitic relaxation times decrease very slightly. Dynamic differential scanning calorimetry results show two glass transitions in the case of a 25% crystalline sample and a single transition for noncrystallized material. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Developing electrically conductive polypropylene/polyamide6/carbon black composites with microfibrillar morphology
Authors: Garmabi Hamid , Naficy Sina
Published: August 2007

We have established that the PP/PA6/CB composite with 3D microfibrillar conducting network can be prepared in situ using melt spinning process. CB particles preferably were localized at the interface between polypropylene as the matrix and PA6 microfibrils, which act as the conducting paths inside the matrix. The percolation threshold of the system reduced when aspect ratio of the conducting phase was increased by developing microfibrillar morphology. The effect of annealing process on the conductivity of PP/PA6/CB composite with co‐ continuous and microfibrillar morphologies was studied. It was observed that, annealing process forces CB particles towards the interface (2D space) of PP and PA6 co‐continuous phases, and percolation threshold and critical exponent of classical percolation theory will be decreased, while the conductivity of conducting composite with microfibrillar morphology was not affected considerably by annealing process at temperatures either higher or lower than the melting point of the PA6 microfibrils. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Synthesis, characterization, and kinetic study of functional polystyrenes
Authors: Doğan Fatih , Kaya İsmet , Dayan Osman , Özdemir Eyüp
Published: August 2007

In this study, functionalization of polystyrene (PS) (Mn = 2.5 × 105) was carry out with maleic anhydride in the presence of boron trifluoride dietyhletherade (BF3 OEt2) as catalyst and then functional PS was subjected to condensation reaction with phenyl hydrazine. The structures of both of them were determined by using FTIR, 1H‐NMR, elemental analysis, thermogravimetric analysis (TGA) and differential thermal analysis (DTA) techniques. Some physical properties of these two products were investigated and the kinetic parameters of solid state decomposition reactions were determined from TGA curves. The intrinsic viscosity [η] values of modified PS and condensation products (cPs) found to be 1.024 and 0.7036 dL g−1, respectively. According to TGA, the weight losses of modified PS and cPs were found to be 84.03 and 81.86%, respectively, at 500°C. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Viscoelastic properties of natural rubber composites reinforced by defatted soy flour and carbon black co‐filler
Authors: Jong L.
Published: August 2007

Filler mixtures of defatted soy flour (DSF) and carbon black (CB) were used to reinforce natural rubber (NR) composites and their viscoelastic properties were investigated. DSF is an abundant and renewable commodity and has a lower material cost than CB. Aqueous dispersions of DSF and CB were first mixed and then blended with NR latex to form rubber composites using freeze‐drying and compression molding methods. A 40% co‐filler reinforced composite with a 1 : 1 DSF : CB ratio exhibited a 90‐fold increase in the rubber plateau modulus compared with unfilled NR, showing a significant reinforcement effect by the co‐filler. The effect, however, is lower than that observed in the carboxylated styrene–butadiene rubber composites reported earlier, indicating a significant effect from the rubber matrix. The co‐filler composites have elastic moduli between those of DSF and CB reinforced composites. Stress softening and recovery experiments indicated that the co‐filler composites with a higher CB content tend to have a better recovery behavior; however, this can not be simply explained from the recovery behaviors of the single filler (DFS and CB) composites. CB composites prepared by freeze‐drying show a strain‐induced reorganization of fillers. Strain sweep experiment data fit with the Kraus model indicates the co‐filler composites with a higher CB content are more elastic, which is consistent with the recovery experiments. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Synthesis and application of polyoxyethylene‐grafted cationic polyamidoamine dendrimers as retention aids
Authors: Peng Xiaochun , Peng Xiaohong , Zhao Jianqing
Published: August 2007

Novel derivatives of fifth‐generation polyamidoamine, comprising polyoxyethylene macromonomer and acrylolyoxyethyl trimethylammonium chloride units, were synthesized. The polyoxyethylene‐grafted cationic polyamidoamine dendrimers were characterized with Fourier transform infrared,1H‐NMR,13C‐NMR, and elemental analysis. The synthesis recipes and properties of the dendrimers were studied. The retention efficiency of the dendrimers was determined and discussed. Highly effective retention aids were obtained in retention experiments with broadleaf wood pulp fibers. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Factors influencing magnetic polymer microspheres prepared by dispersion polymerization
Authors: Zeng Hongmei , Lai Qiongyu , Liu Xueqi , Wen De , Ji Xiaoyang
Published: August 2007

Magnetic iron oxide (Fe3O4) was prepared by a coprecipitation method. Core–shell composite magnetic polymer microspheres with carboxyl groups were synthesized by the dispersion polymerization of styrene and acrylic acid in the presence of magnetic oxide, and dibenzoyl peroxide was used as an initiator. The synthesized magnetic polymer microspheres were characterized with X‐ray diffraction, transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, and so forth. The results indicated that the product was single‐phase Fe3O4, and its average size was about 10 nm. The configuration of the microspheres, which contained carboxyl groups, was spherical, and the average size was about 2 μm. The results of vibrating sample magnetometry tests showed that the magnetic powders produced by different surfactants had different saturation magnetizations. When poly(ethylene glycol) with a weight‐average molecular weight of 4000 was used as a surfactant, the saturation magnetization of the samples reached 69.2 emu/g. The factors that affected the shape, magnetism, size, and distribution of the microspheres were also studied. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Vulcanization of polybutadiene rubber with dipentamethylene thiuram tetrasulfide
Authors: Posadas P. , Fernández A. , Brasero J. , Valentín J. L. , Marcos A. , Rodríguez A. , González L.
Published: August 2007

The cure of polybutadiene rubber (BR) with sulfur donor dipentamethylene thiuram tetrasulfide (DPTT) does not show reversion reaction, in contrast with similar natural rubber compounds. No polysulfure links are formed; whereas a great amount of CC crosslinks are produced. The addition of tetramethyl thiuram monosulfidic (TMTM) strongly affects the crosslinking process. Mechanical properties of the cured compounds are poor. In DPTT, curing of BR the radical species produced through homolitic cleavage of DPTT molecule seems to have sufficient energy to produce crosslinking, via allylic abstraction, and also initiate the polymerization of double bonds producing areas of high crosslinking density that induce early material failure. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 106: 3481–3487, 2007
Influences of catalysis and dispersion of organically modified montmorillonite on flame retardancy of polypropylene nanocomposites
Authors: Song Rongjun , Wang Zhe , Meng Xiaoyu , Zhang Baoyan , Tang Tao
Published: August 2007

The degradation and flame retardancy of polypropylene/organically modified montmorillonite (PP/OMMT) nanocomposite were studied by means of gas chromatography‐mass spectrometry and cone calorimeter. The catalysis of hydrogen proton containing montmorillonite (H‐MMT) derived from thermal decomposition of (alkyl) ammonium in the OMMT on degradation of PP strongly influence carbonization behavior of PP and then flame retardancy. Brønsted acid sites on the H‐MMT could catalyze degradation reaction of PP via cationic mechanism, which leads to the formation of char during combustion of PP via hydride transfer reaction. A continuous carbonaceous MMT‐rich char on the surface of the burned residues, which work as a protective barrier to heat and mass transfer, results from the homogeneous dispersion of OMMT in the PP matrix and appropriate char produced. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Chemical modification of polyaniline by N‐grafting of polystyrene synthesized via ATRP
Authors: Gheybi Homa , Abbasian Mojtaba , Moghaddam Peyman Najafi , Entezami Ali Akbar
Published: August 2007

The N‐substituted polyaniline (PANi) was synthesized by incorporation of bromine‐terminated polystyrene (PS‐Br) onto the emeraldine form of polyaniline. End brominated polystyrene was synthesized by atom transfer radical polymerization (ATRP) technique and then deprotonated polyaniline was reacted with PS‐Br to prepare PS‐grafted PANi (PS‐g‐PANi) copolymer through N‐grafting reaction. The degree of N‐grafting can be controlled by adjusting the molar feed ratio of PS‐Br to the number of repeat units of PANi. The microstructure and compositions of the PS‐g‐PANi copolymers with different degrees of N‐substitution were characterized by FT‐IR, elemental analysis, differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). The cyclicvoltammetry shows that the electroactivity of N‐substituted PANi is strongly dependent on the degree of N‐grafting. The solubility of PS‐g‐PANi copolymers in common organic solvents such as tetrahydrofuran and chloroform was improved by increasing the degree of N‐grafting, and also the samples are partially soluble in xylene. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Techniques for Modeling Muscle‐induced Forces in Finite Element Models of Skeletal Structures
Authors: Grosse Ian R. , Dumont Elizabeth R. , Coletta Chris , Tolleson Alex
Published: August 2007

This work introduces two mechanics‐based approaches to modeling muscle forces exerted on curvilinear bone structures and compares the results with two traditional ad hoc methods of muscle loading. These new models use a combination of tensile, tangential, and normal traction loads to account for muscle fibers wrapped around curved bone surfaces. A computer program was written to interface with a commercial finite element analysis tool to automatically apply traction loads to surface faces of elements in muscle attachment regions according to the various muscle modeling methods. We modeled a highly complex skeletal structure, the skull of a Jamaican fruit bat (Artibeus jamaicensis), to compare the four muscle‐loading methods. While reasonable qualitative agreement was found in the states of stress of the skull between the four muscle load modeling methods, there were substantial quantitative differences predicted in the stress states in some high stressed regions of the skull. Furthermore, our mechanics‐based models required significantly less total applied muscle force to generate a bite‐point reaction force identical to those produced by the ad hoc muscle loading models. Although the methods are not validated by in vivo data, we submit that muscle‐load modeling methods that account for the underlying physics of muscle wrapping on curved bone surfaces are likely to provide more realistic results than ad hoc approaches that do not. We also note that, due to the geometric complexity of many bone structures—such as the skull analyzed here—load transmission paths are difficult to conceptualize a priori. Consequently, it is difficult to predict spatially where the results of finite element analyses are likely to be compromised by using ad hoc muscle modeling methods. For these reasons, it is recommended that a mechanics‐based method be adopted for determination of the proper traction loads to be applied to skeletal structures due to muscular activity. Anat Rec, 290:1069–1088, 2007. © 2007 Wiley‐Liss, Inc.
Structural Characteristics and Development of Ampullary Organs in Acipenser naccarii
Authors: Camacho Susana , Ostos Maria Del Valle , Llorente José Ignacio , Sanz Ana , García Manuel , Domezain Alberto , Carmona Ramón
Published: August 2007

Ampullary organs of Acipenser naccarii sturgeons were examined by optical and electronic microscopy (transmission electron microscopy and scanning electron microscopy) from hatching until 1 month later when the juvenile phase is completely established. It was observed that, when A. naccarii begins to feed actively, the ultrastructural characteristics of ampullary organs already correspond to those of adult animals. These organs may, therefore, be functional and, together with taste buds, facilitate food search after exhaustion of yolk sac food reserves. Mature ampullary organs of A. naccarii are formed by an ampulla that communicates with the exterior by means of a short channel. These ampullae correspond to the sensory portion of these receptors and are formed by two cell types: receptor cells and support cells. Receptor cells present a kinocilium on their free surface and establish ribbon synapses with axon nerve endings that arise from the underlying conjunctive tissue. Support cells enclose receptor cells, bear stereocilia and occasional cilia, and are of a secretory nature. The mucus associated with ampullary organs mainly comprises neutral mucopolysaccharides, whereas mucopolysaccharides are usually acid in other fish groups. Anat Rec, 290:1178–1189, 2007. © 2007 Wiley‐Liss, Inc.
Neuromuscular Anatomy and Evolution of the Cetacean Forelimb
Authors: Cooper Lisa Noelle , Dawson Susan D. , Reidenberg Joy S. , Berta Annalisa
Published: August 2007

The forelimb of cetaceans (whales, dolphins, and porpoises) has been radically modified during the limb‐to‐flipper transition. Extant cetaceans have a soft tissue flipper encasing the manus and acting as a hydrofoil to generate lift. The neuromuscular anatomy that controls flipper movement, however, is poorly understood. This study documents flipper neuromuscular anatomy and tests the hypothesis that antebrachial muscle robustness is related to body size. Data were gathered during dissections of 22 flippers, representing 15 species (7 odontocetes, 15 mysticetes). Results were compared with published descriptions of both artiodactyls and secondarily aquatic vertebrates. Results indicate muscle robustness is best predicted by taxonomic distribution and is not a function of body size. All cetaceans have atrophied triceps muscles, an immobile cubital joint, and lack most connective tissue structures and manus muscles. Forelimbs retain only three muscle groups: triceps (only the scapular head is functional as the humeral heads are vestigal), and antebrachial extensors and flexors. Well‐developed flexor and extensor muscles were found in mysticetes and basal odontocetes (i.e., physeterids, kogiids, and ziphiids), whereas later diverging odontocetes (i.e., monodontids, phocoenids, and delphinids) lack or reduce these muscles. Balaenopterid mysticetes (e.g., fin and minke whales) may actively change flipper curvature, while basal odontocetes (e.g., sperm and beaked whales) probably stiffen the flipper through isometric contraction. Later diverging odontocetes lack musculature supporting digital movements and are unable to manipulate flipper curvature. Cetacean forelimbs are unique in that they have lost agility and several soft tissue structures, but retain sensory innervations. Anat Rec, 290:1121–1137, 2007. © 2007 Wiley‐Liss, Inc.
Somatosensory Nuclei of the Manatee Brainstem and Thalamus
Authors: Sarko Diana K. , Johnson John I. , Switzer Robert C. , Welker Wally I. , Reep Roger L.
Published: August 2007

Florida manatees have an extensive, well‐developed system of vibrissae distributed over their entire bodies and especially concentrated on the face. Although behavioral and anatomical assessments support the manatee's reliance on somatosensation, a systematic analysis of the manatee thalamus and brainstem areas dedicated to tactile input has never been completed. Using histochemical and histological techniques (including stains for myelin, Nissl, cytochrome oxidase, and acetylcholinesterase), we characterized the relative size, extent, and specializations of somatosensory regions of the brainstem and thalamus. The principal somatosensory regions of the brainstem (trigeminal, cuneate, gracile, and Bischoff's nucleus) and the thalamus (ventroposterior nucleus) were disproportionately large relative to nuclei dedicated to other sensory modalities, providing neuroanatomical evidence that supports the manatee's reliance on somatosensation. In fact, areas of the thalamus related to somatosensation (the ventroposterior and posterior nuclei) and audition (the medial geniculate nucleus) appeared to displace the lateral geniculate nucleus dedicated to the subordinate visual modality. Furthermore, it is noteworthy that, although the manatee cortex contains Rindenkerne (barrel‐like cortical nuclei located in layer VI), no corresponding cell clusters were located in the brainstem (“barrelettes”) or thalamus (“barreloids”). Anat Rec, 290:1138–1165, 2007. © 2007 Wiley‐Liss, Inc.
Optical Coherence Tomography as a Tool for Measuring Morphogenetic Deformation of the Looping Heart
Authors: Filas Benjamen A. , Efimov Igor R. , Taber Larry A.
Published: August 2007

Optical coherence tomography (OCT) was used to investigate morphogenesis of the embryonic chick heart during the first phase of looping (c‐looping), as the heart bends and twists into a c‐shaped tube. The present study focuses on the morphomechanical effects of the splanchnopleure (SPL), a membrane that has been shown to play a major role in cardiac torsion by pressing against the ventral surface of the heart. Without the SPL, rightward torsion (rotation) is delayed. The images show that compressive forces exerted by the SPL alter the shapes of the heart tube and primitive atria, as well as their spatial relationships. The SPL normally holds the heart in the plane of the embryo and forces cardiac jelly (CJ) out of adjacent regions in the atria. When the SPL is removed, cross‐sections become more circular, CJ is more uniformly distributed, and the heart displaces ventrally. In addition, OCT‐based morphogenetic strain maps were measured during looping by tracking the three‐dimensional motions of microspheres placed on the myocardium. The spatial–temporal patterns of the strains correlated well with the observed behavior of the heart, including delayed torsion that occurs in SPL‐lacking embryos. These results illustrate the potential of OCT as a tool in studies of morphogenesis, as well as provide a better understanding of the mechanical forces that drive cardiac looping. Anat Rec, 290:1057–1068, 2007. © 2007 Wiley‐Liss, Inc.
Innervation and Neurotransmitter Localization in the Lung of the Nile bichir Polypterus bichir bichir
Authors: Zaccone Giacomo , Mauceri Angela , Maisano Maria , Giannetto Alessia , Parrino Vincenzo , Fasulo Salvatore
Published: August 2007

Anatomical and functional studies of the autonomic innervation in the lung of dipnoan fishes and the bichirs are lacking. The present immunohistochemical studies demonstrated the presence of nerve fibers in the muscle layers of the lung of the bichir, Polypterus bichir bichir, and identified the immunoreactive elements of this innervation. Tyrosine hydroxylase, acetylcholinesterase, and peptide immunoreactivity was detected in the intramural nerve fibers. Extensive innervation was present in the submucosa where adenylatecyclase/activating polypeptide 38, substance P, P2X2, and 5‐hydroxytryptamine (5‐HT)–immunoreactive nerve fibers mainly supplied blood vessels. A collection of monopolar neurons located in the submucosal and the muscular layers of the glottis expressed a variety of various transmitters. These neurons may be homologous to ganglion cells in the branchial and pharyngeal rami of the vagus in fishes. Nerves containing 5‐HT and P2X2 receptor immunoreactivity projected to the lung epithelium. Associated with neuroepithelial cells in mucociliated epithelium, were neuronal nitric oxide synthase–immunopositive axons. The physiological function of this innervation is not known. The present study shows that the pattern of autonomic innervation of the bichir lung may by similar in its elements to that in tetrapods. Anat Rec, 290:1166–1177, 2007. © 2007 Wiley‐Liss, Inc.
Linear and Geometric Morphometric Analysis of Long Bone Scaling Patterns in Jurassic Neosauropod Dinosaurs: Their Functional and Paleobiological Implications
Authors: Bonnan Matthew F.
Published: August 2007

Neosauropod dinosaurs were gigantic, herbivorous dinosaurs. Given that the limb skeleton is essentially a plastic, mobile framework that supports and moves the body, analysis of long bone scaling can reveal limb adaptations that supported neosauropod gigantism. Previously, analyses of linear dimensions have revealed a relatively isometric scaling pattern for the humerus and femur of neosauropods. Here, a combined scaling analysis of humerus and femur linear dimensions, cortical area, and shape across six neosauropod taxa is used to test the hypothesis that neosauropod long bones scaled isometrically and to investigate the paleobiological implications of these trends. A combination of linear regression and geometric morphometrics analyses of neosauropod humeri and femora were performed using traditional and thin‐plate splines approaches. The neosauropod sample was very homogeneous, and linear analyses revealed that nearly all humerus and femur dimensions, including cortical area, scale with isometry against maximum length. Thin‐plate splines analyses showed that little to no significant shape change occurs with increasing length or cortical area for the humerus or femur. Even with the exclusion of the long‐limbedBrachiosaurus, the overall trends were consistently isometric. These results suggest that the mechanical advantage of limb‐moving muscles and the relative range of limb movement decreased with increasing size. The isometric signal for neosauropod long bone dimensions and shape suggests these dinosaurs may have reached the upper limit of vertebrate long bone mechanics. Perhaps, like stilt‐walkers, the absolutely long limbs of the largest neosauropods allowed for efficient locomotion at gigantic size with few ontogenetic changes. Anat Rec, 290:1089–1111, 2007. © 2007 Wiley‐Liss, Inc.
Conjunctival Lymphoid Follicles in New World Rodents
Authors: Astley Roger A. , Chodosh James , Caire William , Wilson Gregory M.
Published: August 2007

We report for the first time, the detection of conjunctival lymphoid follicles (CLF) in the eyes of New World rodents. CLF were found in 7 of the 15 species examined, 6 of the 10 genera, and in at least one individual in four families of rodents. These follicles are dense collections of leukocytes in the conjunctival substantia propria with a thinned overlying epithelium lacking in goblet cells. Although the precise location of CLF within the conjunctiva varied from species to species, all CLF were found in the fornix of the conjunctival sac. In general, size and complexity of CLF varied with the size of the eye; the larger the eye, the larger and more complex the CLF. Our findings also reveal that some species of New World rodents, like the majority of Old World rodents examined in this and previous studies might lack CLF. However, until larger samples are examined, this is difficult to state with certainty. Consequently, the presence/absence of CLF at this point might not be informative for phylogenetic comparisons. Our findings also suggest the deer mouse,Peromyscus maniculatus, might serve as a useful model species for studying ocular infections and immunology of the eye. Anat Rec, 290:1190–1194, 2007. © 2007 Wiley‐Liss, Inc.
Mechanism of Formation of Human Calcium Oxalate Renal Stones on Randall's Plaque
Authors: Evan Andrew P. , Coe Fredric L. , Lingeman James E. , Shao Youzhi , Sommer Andre J. , Bledsoe Sharon B. , Anderson Jennifer C. , Worcester Elaine M.
Published: August 2007

Although calcium oxalate (CaOx) renal stones are known to grow attached to renal papillae, and specifically to regions of papillae that contain Randall's plaque (interstitial apatite deposits), the mechanisms of stone overgrowth on plaque are not known. To investigate the problem, we have obtained biopsy specimens from two stone patients that included an attached stone along with its tissue base and have studied the ultrastructural features of the attachment point using light and transmission electron microscopy, Fourier transform infrared spectroscopy (μ‐FTIR), and immunohistochemical analysis. The epithelium is disrupted at the attachment site. The denuded plaque that borders on the urinary space attracts an envelope of ribbon‐like laminates of crystal and organic matrix arising from urine ions and molecules. Into the matrix of this ribbon grow amorphous apatite crystals that merge with and give way to the usual small apatite crystals imbedded in stone matrix; eventually CaOx crystals admix with apatite and become the predominant solid phase. Over time, urine calcium and oxalate ions gradually overgrow on the large crystals forming the attached stone. Anat Rec, 290:1315‐1323, 2007. © 2007 Wiley‐Liss, Inc.
Allometries Throughout the Late Prenatal and Early Postnatal Human Craniofacial Ontogeny
Authors: Sardi Marina L. , Ventrice Fernando , Ramírez Rozzi Fernando
Published: August 2007

Craniofacial shape changes throughout the late prenatal and early postnatal ontogeny (32–47 weeks of gestational age) were explored. The purpose was to evaluate whether the skull follows an allometric growth pattern, as was observed in other ontogenetic periods, and to assess shape variation patterns for the cranial vault, cranial base, and face. Thirty three‐dimensional landmarks were registered in 54 skulls. Wire‐frames were built with landmarks to observe shape variation in the following cranial components: anteroneural, midneural, posteroneural, optic, respiratory, masticatory, and alveolar. The landmark configurations were subjected to generalized Procrustes analyses, and the shape coordinates obtained were subjected to Principal Components Analyses. Multivariate regression of the shape variables (the principal components) on the size vector (the centroid size) was performed to assess allometries. Transformation grids were constructed to identify how cranial components interact across ontogeny. Results indicated that highly significant shape changes depend on size changes. Important shape variation in the vault, small variation in the cranial base, and no variation in the face were observed. Brain growth is proposed to be the major influence on craniofacial shape change, which produces a relative elongation and compression of midneural and posteroneural components. The cranial base elongates by intrinsic factors and affects position of the face. Ontogenetically, the cranial base seems to be independent with respect to brain growth, in contrast to what has been suggested in comparisons at higher taxonomic levels. Anat Rec, 290:1112–1120, 2007. © 2007 Wiley‐Liss, Inc.
Internal Kinematics of the Tongue During Feeding in Pigs
Authors: Shcherbatyy Volodymyr , Liu Zi‐Jun
Published: August 2007

Six ultrasonic crystals (Ø2 mm) were implanted into the tongue body to form a wedge‐shaped configuration in six 12‐week‐old Yucatan minipigs. These crystals allow recording of the distance changes in bilateral lengths (RL/LL) and base thicknesses (RT/LT), and anterior (AW) and posterior (dorsal and ventral, PDW and PVW) widths during natural feeding. Results indicated that changes in all measured dimensions were stereotypical with considerable regularity. The greatest dimensional changes during chewing were seen in the AW (33.3%), significantly larger than those in other dimensions (P < 0.05–0.001). During ingestion, change in all widths and thicknesses reduced significantly compared with those during chewing (P < 0.05), but changes in the lengths (RL/LL) were significantly larger than those during chewing (P < 0.01). During drinking, overall dimensional changes reduced and amplitudes were symmetrically distributed in all dimensions. The timing analysis indicated that, during chewing, the reversal of dimensional decrease to increase in the PVW occurred first, followed by those of PDW, AW, RT/LT, and RL/LL (P < 0.05). During ingestion, the AW started widening first. Time sequence of these reversals during drinking was similar to that during chewing, but RT/LT thickening was behind RL/LL lengthening. These results suggested that during natural feeding, regional tongue deformations are rhythmic and stereotypical similar to jaw movement. The reversals of expansion–contraction of various dimensions are not synchronous, but occur in a sequential manner in timing. Tongue internal deformations are task‐specific in both timing and amplitude. The dimensional expansions–contractions are dominant in the transverse and sagittal planes during chewing and ingestion, respectively, but are smaller and more symmetrically distributed across various dimensions during drinking. Anat Rec, 290:1288‐1299, 2007. © 2007 Wiley‐Liss, Inc.
Ultrastructure and Estrogen Regulation of the Lymphatic Stomata of Ovarian Bursa in Mice
Authors: Li Meng , Zhou Tian‐Hua , Gao Yun , Zhang Ning , Li Ji‐Cheng
Published: August 2007

The ovarian bursa is a key player in maintaining adaptive ovarian microenvironment for ovulation. The lymphatic stomata are believed to be a major contributor to execute the function of the ovarian bursa, whereas little is known about their ultrastructure and regulation. Here, we examined the ultrastructure of lymphatic stomata in mouse ovarian bursa by scanning electron microscopy and transmission electron microscopy and investigated its regulation by estrogen. We found that the mesothelium on the visceral layer of mouse ovarian bursa was composed of the cuboidal and flattened cells. The lymphatic stomata with round and oval shapes were mainly among the cuboidal cells. The particles, cells, and fluid passed through the stomata and entered into the lymphatic drainage unit composed of connective tissue and lymphatic endothelial cells beneath the stomata. We also used trypan blue as a tracer and found that the absorption of trypan blue through the lymphatic stomata was increased by estrogen that enlarged the average opening area of lymphatic stomata. Furthermore, we detected that there existed estrogen receptors in the nuclei of the mesothelial cells on the visceral ovarian bursa by using immunoelectron microscopy. Taken together, these data suggest that both the absorption and opening area of the lymphatic stomata in mouse ovarian bursa may be influenced by estrogen. Anat Rec, 290:1195‐1202, © 2007 Wiley‐Liss, Inc.
Appearance of Crypt Neurons in the Olfactory Epithelium of the Skate Raja clavata During Development
Authors: Ferrando Sara , Bottaro Massimiliano , Pedemonte Federico , De Lorenzo Simone , Gallus Lorenzo , Tagliafierro Grazia
Published: August 2007

Crypt neurons are olfactory receptor cells located in the olfactory epithelium of fishes. They exhibit a peculiar and well‐recognizable morphology, although their odorant specificity is still unknown. Data on their appearance during development are few and far between. This study set out to identify the time at which crypt neurons appeared in the skate, Raja clavata, using histological and immunohistochemical methods. For this purpose, embryos and juveniles at different stages of development, from 13 weeks after laying (11 weeks before hatching) to 24 weeks after hatching, were examined. The crypt neurons were identified on a morphological basis. An anti–α‐tubulin antibody and two lectins (wheat germ agglutinin and peanut agglutinin) were used to highlight morphological details. The olfactory marker protein was detected by immunohistochemistry, because this protein is a marker of neuronal maturity in vertebrates. The crypt neurons could be detected by their morphology at 15 weeks after laying and became strongly olfactory marker protein immunoreactive 22 weeks after laying. Although involvement of crypt neurons in reproductive behavior has been inferred in various studies on bony fishes, their early presence in skate embryos and juveniles may suggest that they are not exclusively involved in sexual behavior. Anat Rec, 290:1268‐1272, 2007. © 2007 Wiley‐Liss, Inc.
Lobe Identity in the Mongolian Gerbil Prostatic Complex: A New Rodent Model for Prostate Study
Authors: Rochel Sabrina Santos , Bruni‐Cardoso Alexandre , Taboga Sebastião Roberto , Vilamaior Patricia Simone Leite , Góes Rejane Maira
Published: August 2007

Knowledge of structural and physiological differences among the prostatic lobes (PL) is the basis for development of experimental studies in traditional laboratory rodents. Although Mongolian gerbil reproductive organs have been increasingly investigated, its prostate structure is far from being properly known, and investigations of this organ focused on the ventral lobe (VL). Thus, the present study provides a thorough morphological description of prostatic complex in the male adult gerbil on the basis of topographic, histological, and ultrastructural analysis and ductal branching. Like other rodents, four pairs of PL were observed. However, in contrast to the rat and mouse, the VL is the least voluminous component and the dorsolateral lobe (DLL) is the most prominent and spatially isolated from remaining PL. The occurrence of a dorsal lobe (DL), hidden between bladder and insertion of seminal vesicles, has not been mentioned in previous reports with Mongolian gerbil. Collagenase digestion followed by microdissection revealed that, except for DL, which has a tubular‐acinar organization, all PL exhibit tubular organization and variable ductal branching. Distinct histological and ultrastructural features such as secretory epithelium, aspect of luminal secretion and stromal organization are reported for each PL and are confirmed by morphometric and stereological methods. Histological sections showed at least three intralobar segments in VL and DL. Ultrastructural analysis evidenced that, although luminal epithelial cells of PL share typical features of exocrine secretory cells, there are striking lobe phenotypical variations. Both merocrine and apocrine pathways are observed in variable rates in all PL, with the predominance of the former in the DLL and the latter in the CG. The morphological observations presented herein point to distinct structural identities for each PL, which probably reflects specific functional compromise of seminal fluid secretion. These data also point to the gerbil as a good model for investigations concerning the regulation of prostate development and homeostasis, mainly with regard to the dorsal and dorsolateral PL. Anat Rec, 290:1233‐1247, 2007. © 2007 Wiley‐Liss, Inc.
Personalized recommendation with adaptive mixture of markov models
Authors: Liu Yang , Huang Xiangji , An Aijun
Published: August 2007

With more and more information available on the Internet, the task of making personalized recommendations to assist the user's navigation has become increasingly important. Considering there might be millions of users with different backgrounds accessing a Web site everyday, it is infeasible to build a separate recommendation system for each user. To address this problem, clustering techniques can first be employed to discover user groups. Then, user navigation patterns for each group can be discovered, to allow the adaptation of a Web site to the interest of each individual group. In this paper, we propose to model user access sequences as stochastic processes, and a mixture of Markov models based approach is taken to cluster users and to capture the sequential relationships inherent in user access histories. Several important issues that arise in constructing the Markov models are also addressed. The first issue lies in the complexity of the mixture of Markov models. To improve the efficiency of building/maintaining the mixture of Markov models, we develop a lightweight adapt‐ive algorithm to update the model parameters without recomputing model parameters from scratch. The second issue concerns the proper selection of training data for building the mixture of Markov models. We investigate two different training data selection strategies and perform extensive experiments to compare their effectiveness on a real dataset that is generated by a Web‐based knowledge management system, Livelink.
Enantiopure Double‐Helical Phenylene Ethynylene Cyclophynes with the 2,2′‐Binaphthyl Template
Authors: An De‐Lie , Zhang Ying‐Jun , Chen Qiang , Zhao Wen‐Ying , Yan Hong , Orita Akihiro , Otera Junzo
Published: August 2007

New types of enantiopure compounds were synthesized to gain better insight into the structural features of phenylene ethynylene cyclophynes. Besides the previously obtained meta‐substituted arylene ethynylenes, 1, ortho‐connected phenylene ethynylene units were incorporated to give cyclophynes with ortho/meta and ortho/ortho connection modes, 2 and 3. Furthermore, a diphenylethyne component was also accommodated in 4. Both ab initio calculations and NMR spectra suggest a large amount of strain for 2 but less strain for 3 and 1 a, the latter having the smallest ring size among cyclophynes with the meta/meta connection mode. The CD spectra of 2 and 3 showed a characteristic shoulder at around 340 nm, similar to the case of 1 a. This implies that the aromatic acetylene bonds cross over each other in the double‐helical structure. These results indicate that chirality information is useful for probing the persistency of molecular shape.
Optimizing lignocellulosic feedstock for improved biofuel productivity and processing
Authors: Han Kyung‐Hwan , Ko Jae‐Heung , Yang Seung Hwan
Published: August 2007

Liquid fuels from lignocellulosic materials, such as wood, offer an attractive alternative to fossil fuel. Lignocellulosic biomass is composed of a complex mixture of cellulose, hemicellulose, and lignin. As structural polymers, the matrix of hemicellulose and lignin surround the cellulose component of the plant cell wall to protect it against enzymatic attack. The resistance of this complex to enzymatic attack is a major impediment to commercial bioconversion of lignocellulosic biomass. Furthermore, proportional variability within the mixture of the three major components varies, depending on the species of feedstock used, growing site, climate, age, and the part of the plant harvested. This fact presents process design and operating challenges for the fermentation of sugars derived from lignocellulosic feedstocks. The essentially uncontrolled variability of biomass properties also presents major difificulties in understanding the fundamental processes involved in limiting the digestion of cell walls to fermentable sugars. Energy crops must be optimized for ‘low‐input production’ systems and efficiency of pretreatment and hydrolysis to derive sugars for further fermentation to produce ethanol. Recent advances in the molecular biology of wood formation and cell‐wall biosynthesis have provided new tools to tailor the biomass composition. This review summarizes recent advances in the understanding of the molecular mechanisms regulating the biochemical and developmental processes of woody biomass production. Potential areas of future research in optimizing lignocellulosic feedstock for bioenergy production are identified. © 2007 Society of Chemical Industry and John Wiley & Sons, Ltd
Is the expansion of biofuels at odds with the food security of developing countries?
Authors: Ugarte Daniel De La Torre , He Lixia
Published: August 2007

The production of ethanol and biodiesel has been growing rapidly in Brazil, the USA and the EU. Although the current share of overall fuel consumption is quite small, if biofuels become a global mainstream energy source, their production will eventually affect the traditional food and feedstock market. This may cause further problems in already food‐insecure nations (mainly developing countries) owing to food price increases. This perspective discusses possible responses to supply variability that developing countries may make to mitigate the odds against them and take advantage of the opportunities offered by price increases through efficient marketing systems, investing in agri‐cultural research, improving agricultural practices, and developing an extension system focusing on the sustainable use of limited land and renewable resources. Developing technology that can convert cellulosic materials to biofuels efficiently will also help defuse the demand stress on traditional food supplies worldwide. © 2007 Society of Chemical Industry and John Wiley & Sons, Ltd
Absence of effect of power–frequency magnetic fields exposure on mouse embryonic lens development
Authors: Yao Ke , Yu YiBo , Wang KaiJun , Ye Juan , Lu DeQiang , Jiang Huai
Published: August 2007

There are no reports in the literature investigating the biological effect of power–frequency (50/60 Hz) magnetic fields on embryonic lens development. We investigated whether power–frequency magnetic fields act as an environmental insult and induce changes in morphology or protein and/or transcription factor mRNA expression levels in developing mouse embryonic lenses. Three groups of pregnant mice were exposed to magnetic fields (50 Hz) of varying intensities (0.0, 1.5, and 4.5 mT) for 3 h per day from gestation day (GD) 0 to 18. The embryonic lenses were enucleated on GD 18. The lenses in the three groups were found to be transparent and the lens epithelial cells from the experimental groups exhibited normal ultrastructure comparable to the control. No significant differences were found among the three groups in quantity of water soluble protein (WSP), water insoluble protein (WIP), the ratio of WIP to total protein, and the mRNA expression levels of four well known developmentally regulated DNA‐binding transcription factors: Pax6, Prox1, Sox1, and c‐maf. We preserved one pregnant mouse per group, fed the neonatal mice until 2 weeks of age, and then found the lenses transparent. Our results did not detect any effects on the development of embryonic lenses in mice exposed to power–frequency magnetic fields. Bioelectromagnetics 28:628–635, 2007. © 2007 Wiley‐Liss, Inc.
Zur Beurteilung des Ankündigungsverhaltens von Spannbetonbrücken nach dem Riss‐vor‐Bruch‐Kriterium. Vorschläge zur Vorgehensweise bei gefährdeten Brücken
Authors: Albertin‐Hummel Ursula , Brandt Bernd
Published: August 2007

Bei Spannbetonbrücken steigt mit zunehmender Nutzungsdauer die Bedeutung der Dauerhaftigkeit. Mit numerischen Berechnungen und Bauwerksprüfungen gemäß DIN 1076 wird versucht, ein mögliches Versagen der Bauwerke rechtzeitig erkennen und verhindern zu können sowie das Restrisiko für den Bauherrn zu minimieren. Besonders ältere Spannbetonbrücken mit spannungsrisskorrosionsgefährdetem Spannstahl sind hinsichtlich ihres Ankündigungsverhaltens nach dem Riss‐vor‐Bruch‐Kriterium rechnerisch zu untersuchen und zu bewerten. Ausgehend von diesen numerischen Ergebnissen und ergänzenden Berechnungen lässt sich das bestehende Restrisiko für den Bauherrn hinsichtlich eines Bauwerksversagens beurteilen. Die konstruktive Durchbildung betreffender Bauwerke wird diskutiert. Aufgrund der durchgeführten Untersuchungen werden Vorschläge zur weiteren Vorgehensweise bei älteren gefährdeten Brücken und zur Eingrenzung des Restrisikos erarbeitet. Bei jüngeren Brücken stellt der Nachweis nach dem Riss‐vor‐Bruch‐Kriterium ein Maß für eine ausreichende Robustheit dar.
Exact One‐Sided Confidence Bounds for the Risk Ratio in 2 × 2 Tables with Structural Zero
Authors: Lloyd Chris J. , Moldovan Max V.
Published: August 2007

This paper examines exact one‐sided confidence limits for the risk ratio in a 2 × 2 table with structural zero. Starting with four approximate lower and upper limits, we adjust each using the algorithm of Buehler (1957) to arrive at lower (upper) limits that have exact coverage properties and are as large (small) as possible subject to coverage, as well as an ordering, constraint. Different Buehler limits are compared by their mean size, since all are exact in their coverage. Buehler limits based on the signed root likelihood ratio statistic are found to have the best performance and recommended for practical use. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Microbial production of natural raspberry ketone
Authors: Beekwilder Jules , van der Meer Ingrid M. , Sibbesen Ole , Broekgaarden Mans , Qvist Ingmar , Mikkelsen Joern D. , Hall Robert D.
Published: August 2007

Raspberry ketone is an important compound for the flavour industry. It is frequently used in products such as soft drinks, sweets, puddings and ice creams. The compound can be produced by organic synthesis. Demand for “natural” raspberry ketone is growing considerably. However, this product is extremely expensive. Consequently, there is a remaining desire to better understand how raspberry ketone is synthesized in vivo, and which genes and enzymes are involved. With this information we will then be in a better position to design alternative production strategies such as microbial fermentation. This article focuses on the identification and application of genes potentially linked to raspberry ketone synthesis. We have isolated candidate genes from both raspberry and other plants, and these have been introduced into bacterial and yeast expression systems. Conditions have been determined that result in significant levels of raspberry ketone, up to 5 mg/L. These results therefore lay a strong foundation for a potentially renewable source of “natural” flavour compounds making use of plant genes.