bluuebunny/crossref_metadata_2025 huggingface dataset:
Preoperative combined modality therapy for pancreatic cancer
Authors: Rich Tvvin A. , Evans Douglas B.
Published: October 2004

Combined modality therapy can be administered prior to surgical resection for patients with operable pancreatic cancer. One important criteria used to select patients for this treatment sequence is the absence of arterial vascular encasement by tumor on thin‐section CT scanning; the absence of peritoneal seeding on surgical staging or laparoscopy has been another important parameter used in identifying patients with “localized” disease. Preoperative treatment with infusional chemoradiation uses multiple fields of irradiation delivering a dose of 50.4 Gy in 28 fractions over 51/2 weeks. This is done in conjunction with a continuous infusion of 5‐fluorouracil intravenously at a dosage of 300 mg/m2/day with each day of radiotherapy treatment. The initial results of this protocol indicate acceptable toxicity and no evidence of increased perioperative morbidity or mortality compared to series using operation alone. We conclude that nearly all patients eligible for this combined modality treatment approach complete therapy as prescribed with acceptable toxicity.
Adjuvant therapy for pancreatic cancer
Authors: Douglass Harold O.
Published: October 2004

Although the morbidity and mortality of pancreatic resection for cancer has been remarkably reduced during the last 20 years, there has been little change in long‐term survival. Based on experience in the treatment of locally unresectable but nonmetastatic pancreatic cancer, adjuvant therapies have been devised that do have an impact on survival. The number of pancreatic resections remains low, however. To increase the number of pancreatic resections that might be performed, phase II neoadjuvant trials are under way in several centers. Even if successful, they will have little effect on the proportion of patients with pancreatic cancer who are cured. New, innovative treatments must be explored.
Radiation treatment for rectal cancer
Authors: Cummings B. J.
Published: October 2004

Radiation treatment is widely used in the management of adenocarcinomas of the rectum, either alone or more frequently as part of multimodality treatment protocols. External beam radiation is capable of eradicating about one‐third of bulky but mobile primary rectal cancers and is an alternative to be considered when standard surgery is not possible. Endorectal irradiation, either alone or combined with external beam treatment, has proved highly effective for selected superficial cancers of the distal rectum. Irradiation alone or in conjuction with cytotoxic chemotherapy appears to reduce the risk of tumor progression at the primary site or in regional lymph nodes when combined with local surgical excisions that preserve anorectal function. The treatment of recurrent and metastatic cancer frequently provides palliation, although cure by irradiation is rare.
Antioxidant therapy using high dose vitamin C: Reduction of postburn resuscitation fluid volume requirements
Authors: Matsuda Takayoshi , Tanaka Hideharu , Reyes Hernan M. , Richter Harry M. , Hanumadass Marella M. , Shimazaki Shuji , Matsuda Hiroharu , Nyhus Lloyd M.
Published: October 2004

Twenty‐four guinea pigs with third degree burns over 70% of the body surface area were divided equally into four groups. At 0.5 hours postburn, all groups received Ringer's lactate solution (R/L) according to the Parkland formula. The infusion rate was then reduced to 25% of the Parkland formula at 1.5 hours postburn. Group 1 received only R/L, and groups 2, 3 and 4 received adjuvant vitamin C (14.2 mg/kg/hr) until 4, 8, and 24 hours postburn, respectively. The volume of R/L was reduced by that of vitamin C solution so that the hourly sodium and fluid intake in each group was the same. Groups 1 and 2 demonstrated higher hematocrit and lower cardiac output values than did group 3, suggesting hypovolemia and hemoconcentration in these groups. Group 3 showed hematocrit and cardiac output values equivalent to those in group 4. We conclude that high dose vitamin C infusion maintains hemodynamic stability in the presence of a reduced resuscitation fluid volume provided vitamin C is administered for a minimum of 8 hours postburn.
Recurrent inguinal hernias in infants and children
Authors: Steinau Gerhard , Treutner Karl H. , Feeken Gabriele , Schumpelick Volker
Published: October 2004

The objective of this study was to analyze the etiologic factors possibly associated with the development of recurrent groin hernias in infants and children. For this purpose we analyzed the records of 2754 pediatric patients operated on for primary hernias between 1966 and 1990 at our department who have not had recurrences. They were compared with 28 boys and 4 girls we treated for recurrent hernias during the same period. We found an indirect hernia in 29 cases, a direct hernia in 4 patients, and a femoral hernia in 1 child at the time of reoperation. A significantly high recurrence rate was found to be associated with incarceration (21.9% versus 7.6%) postoperative complications (9.4% versus 1.8%), concomitant diseases (31.2% versus 5.7%), and premature birth. Day case treatment was closely related to concomitant diseases. No impact on the development of recurrences was seen for the surgeons' educational level and the time of day the surgery was performed. Knowledge of the factors contributing to hernia recurrence and perfect surgical technique with reduction of incarcerated hernias and early elective operation may result in fewer recurrences in infants and children.
A combined iterative scheme for identification and control redesigns
Authors: Date Paresh , Lanzon Alexander
Published: October 2004

This work proposes a unified algorithm for identification and control. Frequency domain data of the plant is weighted to satisfy the given performance specifications. A model is then identified from this weighted frequency domain data and a controller is synthesised using the ℋ︁∞loopshaping design procedure. The cost function used in the identification stage essentially minimizes a tight upper bound on the difference between the achieved and the designed performance in the sense of the ℋ︁∞loopshaping design paradigm. Given a model, a method is also suggested to re‐adjust model and weighting transfer functions to reduce further the worst case chordal distance between the weighted true plant and the model. Copyright © 2004 John Wiley & Sons, Ltd.
Iterative correlation‐based controller tuning
Authors: Karimi A. , Mišković L. , Bonvin D.
Published: October 2004

This paper gives an overview on the theoretical results of recently developed algorithms for iterative controller tuning based on the correlation approach. The basic idea is to decorrelate the output error between the achieved and designed closed‐loop systems by iteratively tuning the controller parameters. Two different approaches are investigated. In the first one, a correlation equation involving a vector of instrumental variables is solved using the stochastic approximation method. It is shown that, with an appropriate choice of instrumental variables and a finite number of data at each iteration, the algorithm converges to the solution of the correlation equation. The convergence conditions are derived and the accuracy of the estimates are studied. The second approach is based on the minimization of a correlation criterion. The frequency analysis of the criterion shows that the two norm of the error between the desired and achieved closed‐loop transfer functions is minimized independent of the noise characteristics. This analysis leads to the definition of a generalized correlation criterion which allows the mixed sensitivity problem to be handled in two norm. Copyright © 2004 John Wiley & Sons, Ltd.
Unfalsified model reference adaptive control using the ellipsoid algorithm
Authors: Cabral Fabricio B. , Safonov Michael G.
Published: October 2004

The unfalsified control paradigm which uses as plant information, experimental trajectories of plant signals, is applied to the model reference adaptive control problem. The use of an ellipsoid algorithm overcomes the need of gridding the parameter space used in prior applications of unfalsified control. The application of the ellipsoid algorithm produces a sequence of decreasing volume ellipsoids which contains the set of unfalsified candidates. Simulation results are provided for the control of an unstable plant. Copyright © 2004 John Wiley & Sons, Ltd.
Least squares based self‐tuning control of dual‐rate systems
Authors: Ding Feng , Chen Tongwen
Published: October 2004

A polynomial transformation technique is used to obtain a frequency‐domain model for a dual‐rate system in which the output sampling period is an integer multiple of the input updating period. Based on this model, a self‐tuning control algorithm is proposed by minimizing output tracking error criteria from directly the dual‐rate input–output data. Convergence properties of the algorithm are analysed in detail in the stochastic framework. The output tracking error at the output sampling instants has the property of minimum variance. It is shown that the control algorithm can achieve virtually optimal control asymptotically, ensuring the closed‐loop systems to be stable and globally convergent. A simulation example illustrates the self‐tuning scheme presented. Copyright © 2004 John Wiley & Sons, Ltd.
Role of resonances on microwave heating of oil–water emulsions
Authors: Basak Tanmay
Published: October 2004

A detailed analysis on enhanced heating effects attributed to resonance of microwaves has been carried out to study the efficient heating methodologies for oil–water emulsions. Studies on heating have been carried out for samples incident with microwaves at one side and at both sides. The maxima in average power corresponding to resonances occur at various sample thicknesses for all emulsions and we consider two dominant resonance modes R1 and R2, where the average power at R1 is larger than that at R2. During one side incidence, it is observed that processing rates are greater at the R2 mode for both oil‐in‐water (o/w) and water‐in‐oil (w/o) emulsions, whereas for both‐sides incidence, the R1 mode is favored for o/w emulsion and the R2 mode is advantageous for w/o emulsion. The greater rates in thermal processing are observed when the emulsions (o/w and w/o) are incident at both sides. Current analysis recommends on the efficient way to use microwaves in a customized plane‐wave oven for greater heating effects and determines the optimal sample thicknesses vs. various oil–water contents for thermal processing. The emulsion system is a combination of materials with very low dielectric loss (oil) and high dielectric loss (water), and the effective dielectric response is highly nontrivial to predict the efficient way to heat an emulsion, either o/w or w/o. © 2004 American Institute of Chemical Engineers AIChE J, 50: 2569–2675, 2004
Large‐Eddy simulation of a turbulent reacting liquid flow
Authors: Michioka Takenobu , Komori Satoru
Published: October 2004

A subgrid‐scale (SGS) model for the filtered reaction source term is presented to develop the large‐eddy simulation (LES) of a nonpremixed, turbulent liquid flow with a moderately fast reaction. The SGS model is based on the SGS probability density function (PDF) and SGS conditional expectation. The SGS probability density function (SGS–PDF) is assumed to follow a beta distribution and a simple algebraic model for the SGS conditional expectation is developed using the filtered data obtained from the direct numerical simulation (DNS) of stationary isotropic liquid turbulence with a second‐order chemical reaction. For a rapid reaction, the SGS–PDF model based on the conserved scalar is used as the SGS model. The LES based on these SGS models is applied to a liquid mixing layer flow downstream of a turbulence‐generating grid with a chemical reaction, and the LES predictions of the mean concentration and concentration variance are directly compared with the previous measurements for both moderately fast and rapid reactions to examine the proposed SGS models. The results show that the predictions by the LES are in good agreement with the measurements and the present LES can well describe the diffusive–reactive process in a turbulent reacting liquid flow. © 2004 American Institute of Chemical Engineers AIChE J, 50: 2705–2720, 2004
Removal of NO by a pulsed‐corona reactor combined with in situ absorption
Authors: Huang Liwei , Matsuda Hitoki
Published: October 2004

Removal of NO by nonthermal plasma, combined with in situ absorption, was experimentally investigated with a wire‐in‐tube pulsed‐corona reactor. High pulse voltage was applied to the wire of the reactor and the tube was grounded. For the reactor combined with in situ absorption, the grounding electrode was covered by a Ca(OH)2 layer as the sorbent for in situ capture of the NO oxidation products. It was found that NO removal was much higher by the reactor combined with in situ absorption than by the reactor without Ca(OH)2 sorbent and, meanwhile, the outlet NO2 concentration from the reactor was also suppressed to less than 10 ppm. It was indicated that in situ absorption of the NO2 by Ca(OH)2 was responsible for the promotion of NO removal. The existence of O2 and water vapor in the gas stream is beneficial for NO oxidation, therefore resulting in the significant increase of NO removal. © 2004 American Institute of Chemical Engineers AIChE J, 50: 2676–2681, 2004
Reaction and diffusion during demineralization of animal bone
Authors: Horneman Danielle A. , Ottens Marcel , Hoorneman Marieke , van der Wielen Luuk A. M. , Tesson Martijn
Published: October 2004

The demineralization of animal bone is investigated. Experimental results show an increase in penetration rate of hydrochloric acid into animal bone particles, and thereby increased demineralization, at increasing temperature and concentration of HCl. Fick's law is used to calculate the effective diffusivities of HCl in animal bone from these experimental results, showing a decrease in effective diffusivity at increased HCl concentration, which proves Fick's law unsuitable for describing the process, whereas a Maxwell–Stefan‐based model is used successfully. This model is able to take into account gradients in composition as well as electrical potential, and also addresses the frictional resistances between the various components in the multicomponent system. The results of the Maxwell–Stefan model are in good agreement with the experimental data. From the Maxwell–Stefan model and the experiments, it follows that at high concentrations of HCl, the friction between the diffusing ions (H+, Cl−, H2PO, and Ca2+) becomes more important and lowers the increase of demineralization rate caused by the increase in the concentration gradient. © 2004 American Institute of Chemical Engineers AIChE J, 50:2682–2690, 2004
Effect of liquid films on the drying of porous media
Authors: Yiotis A. G. , Boudouvis A. G. , Stubos A. K. , Tsimpanogiannis I. N. , Yortsos Y. C.
Published: October 2004

The effect is studied of capillarity‐driven viscous flow through macroscopic liquid films during the isothermal drying of porous materials. A mathematical model that accounts for viscous flow in a 2‐D pore network, through both the liquid films and the bulk liquid phase, is presented. The results are compared with previous works that do not account for the effect of films and with experimental findings by other authors. It is shown that film flow is a major transport mechanism in the drying of porous materials, its effect being dominant when capillarity controls the process, which is the case in typical applications. By contrast, viscous flow in the bulk contributes negligibly. The results are then generalized to drying under an applied temperature gradient. © 2004 American Institute of Chemical Engineers AIChE J, 50: 2721–2737, 2004
The structure of supercritical fluid free‐jet expansions
Authors: Khalil Imane , Miller David R.
Published: October 2004

Experimental and numerical studies are reported on the structure of supersonic free‐jet expansions of supercritical CO2 impacting on a flat plate. Numerical calculations for the axisymmetric, two‐dimensional (2‐D) expansion use a time‐dependent finite difference method known as the two‐step Lax‐Wendroff technique, incorporating the Redlich‐Kwong equation of state to model CO2. The numerical results are compared with experimental optical shadowgraph measurements of the jet and shock wave structure, impact pressure and temperature measurements along the plate, and a thermocouple probe of the expansion. Approximations based on ideal gases and quasi‐1‐D flow analysis, often used by researchers, are found to be useful for these supercritical fluid flows. © 2004 American Institute of Chemical Engineers AIChE J, 50: 2697–2704, 2004
Enamel thickness of deciduous and permanent molars in modern Homo sapiens
Authors: Grine F.E.
Published: October 2004

This study presents data on the enamel thickness of deciduous (dm2) and permanent (M1–M3) molars for a geographically diverse sample of modern humans. Measurements were recorded from sections through the mesial cusps of unworn teeth. Enamel is significantly thinner on deciduous than on permanent molars, and there is a distinct trend for enamel to increase in relative thickness from M1 to M3. The relatively thicker enamel of M2s and especially M3s can be related to the overall reduction in size of more distal molar crowns, which has been attained through a differential loss of the dentine component. Enamel tends to be thicker on the protocone than on the paracone, and thicker on the protoconid than on the metaconid, but its distribution is not wholly concordant with models that predict increased thickness as a means by which to counter heavier attritional loss on these “functional” cusps. Indeed, the thickness of enamel tends to be more variable on cusp tips and occlusal surfaces than over the lateral aspects of cusps. The proportionately thicker enamel over the lateral aspects of the protocone and protoconid more likely serves as a means to prolong functional crown life by preventing cusp fracture, rather than being an adaptation to increase the attritional longevity of wear facets. The present data suggest that the human dentition is not predisposed to develop a helicoidal wear plane through the disposition of molar enamel thickness. Am J Phys Anthropol, 2004. © 2004 Wiley‐Liss, Inc.
Synthesis of oligonucleotide‐functionalized magnetic nanoparticles and study on their in vitro cell uptake
Authors: Wagner Kerstin , Kautz Armin , Röder Michael , Schwalbe Manuela , Pachmann Katharina , Clement Joachim H. , Schnabelrauch Matthias
Published: October 2004

Carboxymethyl dextran (CMD) with varying degrees of substitution was prepared and used as biocompatible coating for magnetic iron oxide nanoparticles. An oligonucleotide (19‐mer) was coupled to the CMD‐coated particles as a model compound for DNA fragments. Transmission electron microscopy investigations on the cellular uptake of the particles by different tumor cell lines demonstrated that both the CMD‐coated and the oligonucleotide‐coupled particles are internalized by the cells and deposited in cellular endosomes. The nanoparticles prepared have potential applications in tumor diagnosis and therapy. Copyright © 2004 John Wiley & Sons, Ltd.
Cobalt ferrite–silica core–shell colloids: a magnetic Yukawa system
Authors: Autenrieth T. , Wagner J. , Hempelmann R. , Härtl W. , Robert A. , Grübel G.
Published: October 2004

Colloidal core–shell particles consisting of a magnetic cobalt ferrite core surrounded by a silica shell are prepared via precipitation and a subsequent modified Stöber synthesis. The resulting particles with narrow size distribution interact due to weakly acidic surface groups at the silica shell via a screened Coulomb or Yukawa potential in addition to the magnetic dipole–dipole interaction of the magnetic cores.

The structural characterization of the particles is done by transmission electron microscopy and small‐angle X‐ray scattering (SAXS), and the potential parameters of the electrostatic monopole and magnetic dipole–dipole interactions are determined by laser Doppler electrophoresis and magnetogranulometry, respectively.

Owing to the interaction potential, the particles self‐organize to a liquid‐like ordered structure as determined by SAXS. The magnetic dipole–dipole interaction becomes evident from the anisotropic scattering pattern in the presence of an external magnetic field. Copyright © 2004 John Wiley & Sons, Ltd.
Langevin equation for the rotation of a magnetic particle
Authors: Raible Martin , Engel Andreas
Published: October 2004

We investigate Brownian motion on a curved surface with the help of the covariant Langevin and Fokker–Planck equations. As a special example we address the orientational diffusion of a ferromagnetic particle immersed in a viscous fluid under the influence of a time‐dependent magnetic field. This system may model the recently discovered thermal ratchet behaviour in ferrofluids. Numerical simulations of the Langevin equation are shown to be in good agreement with results from the solution of the Fokker–Planck equation reported previously. Copyright © 2004 John Wiley & Sons, Ltd.
High‐quality structure parameter for magnetic liquids obtained by small‐angle scattering of polarized neutrons
Authors: Heinemann A. , Wiedenmann A. , Kammel M. , Bönnemann H. , Matoussevitch N.
Published: October 2004

The preparation of magnetic liquids with the aid of different aluminium alkyl chains leads to narrow size distributions. A structural investigation of different ferrofluid samples was performed with small‐angle neutron scattering of polarized neutrons (SANSPOL). The use of polarized neutrons extends the known method for composition exploration in nanometre‐scale magnetic systems. For these new possibilities special data‐analysis procedures are indispensable. We use a new simultaneous fitting procedure for the spin‐up, spin‐down and nuclear–magnetic interference term to obtain the structure parameter information. The advantage of this method is the reduction of parameter correlations for the independent model parameters. Copyright © 2004 John Wiley & Sons, Ltd.
Fine structural correlates of the choroid plexus of the lateral cerebral ventricle of the human fetal brain
Authors: Scott David E. , Bergevin Michael
Published: October 2004

The germinal matrix neuroepithelium and the choroidal fissure of the fetal choroid plexus commonly possess microvessels that are often poorly developed. There may be a reduction of type IV collagen that surrounds these fragile microvessels. During the first and second trimester of neural development, these microvessels are friable and can undergo intraventricular hemorrhage under a number of circumstances. Early subtle changes in the integrity of germinal matrix epithelium are not easily visualized by ultrasound. The current investigation employing scanning electron microscopy clearly defines subtle hemorrhagic events and tearing of the germinal matrix neuroepithelium in the brains of human fetuses. A 23‐week‐old fetus survived for 11 days but died from other causes. The choroid plexus of this fetus was compared with the choroid plexus and germinal matrix epithelium of a 22‐week‐old fetus that was the product of an elective termination due to severe anhydramnios of unknown origin and a 19‐week‐old male fetus from an elective termination. All tissues were autopsy material not requiring institutional review board approval. © 2004 Wiley‐Liss, Inc.
Evolution of the special senses in primates: Past, present, and future
Authors: Dominy Nathaniel J. , Ross Callum F. , Smith Timothy D.
Published: October 2004

The present special issue ofThe Anatomical Recordis the result of a symposium entitled Evolution of the Special Senses in Primates. Considered together, the special senses of primates are remarkable because they constitute a singular and definitive suite of mammalian characteristics. Examining their evolution is pivotal for understanding the origin and present‐day variation of primate behavior and ecology. Accordingly, the 14 articles assembled here consider the different constraints and opportunities associated with the uptake and use of physical and chemical stimuli. The present issue brings together experts on different primate sensory modalities and stresses events at the sensory periphery, where the organism is exposed to and comes into contact with its environment. Key topics include color vision, the genetics of olfaction, the morphological basis and significance of chemical communication, and the neural organization and scaling of primate sensory systems. The result is a special issue that both reflects our current understanding of primate sensory modalities and challenges certain fundamental assumptions concerning their evolution. © 2004 Wiley‐Liss, Inc.
High‐resolution computed tomography study of the cranium of a fossil anthropoid primate, Parapithecus grangeri: New insights into the evolutionary history of primate sensory systems
Authors: Bush Eliot C. , Simons Elwyn L. , Allman John M.
Published: October 2004

Extant anthropoids have large brains, small olfactory bulbs, and high‐acuity vision compared with other primates. The relative timing of the evolution of these characteristics may have important implications for brain evolution. Here computed tomography is used to examine the cranium of a fossil anthropoid, Parapithecus grangeri. It is found that P. grangeri had a relatively small brain compared with living primates. In addition, it had an olfactory bulb in the middle of the range for living primates. Methods for relating optic foramen area and other cranial measurements to acuity are discussed. Multiple regression is used to estimate retinal ganglion cell number in P. grangeri. Given currently available comparative data, P. grangeri seems to have had retinal ganglion cell counts intermediate for living primates, overlapping with the upper end of the range for strepsirrhines and possibly with the lower end for anthropoids. © 2004 Wiley‐Liss, Inc.
Three‐dimensional structure and evolution of primate primary visual cortex
Authors: Bush Eliot C. , Allman John M.
Published: October 2004

In this study, three‐dimensional reconstructions of primate primary visual cortex (V1) were used to address questions about its evolution. The three‐dimensional shape of V1 in anthropoids is significantly longer and narrower than in strepsirrhines. This difference is an effect of clade and is not due to differences in activity pattern or V1 size. New measurements of V1 volume were also provided in order to reassess V1 size differences between strepsirrhines and anthropoids. It was found that for a given lateral geniculate nucleus (LGN) volume, anthropoids have a significantly larger V1 than strepsirrhines do. This is important since LGN is the principal source of V1's input. Finally, independent contrasts analysis was used to examine the scaling of V1 relative to LGN, the rest of cortex, and the rest of the brain. It was confirmed that V1 scales with positive allometry relative to LGN. A number of possible explanations for scaling are discussed. V1 scaling may have to do with the tendency of large brains to be more compartmentalized than small brains, or V1 scaling might reflect the geometry of information representation. © 2004 Wiley‐Liss, Inc.
Comparative morphology of the eye in primates
Authors: Kirk E. Christopher
Published: October 2004

Comparative studies of mammalian eye morphology have shown that relative cornea size is an important correlate of visual ecology. Nocturnal species tend to have large corneas relative to eye size as an adaptation for increasing visual sensitivity. By contrast, diurnal species tend to have smaller corneas relative to eye size because their eye morphology maximizes visual acuity. Although qualitative analyses suggest that activity pattern may have a similar influence on eye morphology in primates, various current hypotheses have proposed that either diurnal anthropoids or diurnal lemurs have visual systems that diverge from those of other diurnal mammals. The goal of this analysis is to quantify the relationship between eye morphology and activity pattern in primates and to determine whether primates exhibit variation in eye morphology comparable to that of other mammals. Data on eye size and cornea size were collected for 147 specimens of 55 primate species. These data reveal that, within primate suborders, diurnal species have significantly smaller relative cornea sizes than nocturnal or cathemeral species. Both haplorhines and strepsirrhines thus exhibit variation in eye morphology that is consistent with functional expectations. However, comparisons between the two primate suborders demonstrate that haplorhines and strepsirrhines differ significantly in eye morphology. Whereas strepsirrhines have relative cornea sizes that are similar to nonprimate mammals of comparable activity pattern, diurnal anthropoids have smaller relative cornea sizes than most nonprimate mammals. This derived eye morphology in anthropoids probably evolved in the anthropoid stem lineage as a result of selection for highly acute diurnal vision. © 2004 Wiley‐Liss, Inc.
On the relationship between orbit orientation and binocular visual field overlap in mammals
Authors: Heesy Christopher P.
Published: October 2004

The orbital apertures of Primates are among the most convergent (i.e., facing in the same direction) among mammals. It is often assumed that orbit convergence is associated with binocular visual field overlap and stereoscopic depth perception in primates. Likewise, it is also assumed that orbit orientation reflects the shape of the visual field across mammals. To date, however, no study has demonstrated that orbit and visual field orientation are correlated, much less comparable, across mammals. In this study, data on orbit convergence were collected for a representative sample of mammals for which data on the extent of the visual field are available. Both standard and phylogenetically controlled comparisons were made. The results demonstrate that orbit convergence and binocular visual field overlap are significantly correlated and display a linear relationship. Based on orbit convergence, Primates as a group have the largest binocular visual fields among mammals. © 2004 Wiley‐Liss, Inc.
Primate hearing from a mammalian perspective
Authors: Heffner Rickye S.
Published: October 2004

This review discusses hearing performance in primates and selective pressures that may influence it. The hearing sensitivity and sound‐localization abilities of primates, as indicated by behavioral tests, are reviewed and compared to hearing and sound localization among mammals in general. Primates fit the mammalian pattern with small species hearing higher frequencies than larger species in order to use spectral/intensity cues for sound localization. In this broader comparative context, the restricted high‐frequency hearing of humans is not unusual. All of the primates tested so far are able to hear frequencies below 125 Hz, placing them among the majority of mammals. Sound‐localization acuity has been determined for only three primates, and here also they have relatively good localization acuity (with a minimum audible angle roughly similar to other mammals such as cats, pigs, and opossums). This is in keeping with the pattern among mammals in general, in which species with narrow fields of best vision, such as a fovea, are better localizers than those with broad fields of best vision. Multiple lines of evidence support the view that sound localization is the selective pressure on smaller primates and on other mammals with short interaural distances for hearing high frequencies. © 2004 Wiley‐Liss, Inc.
Primate auditory diversity and its influence on hearing performance
Authors: Coleman Mark N. , Ross Callum F.
Published: October 2004

The auditory region contains numerous structures that have proven useful for phylogenetic classification at various taxonomic levels. However, little work has been done in primates relating differences in morphology to variations in hearing performance. This study documents anatomical and physiological distinctions within primates and begins to address the functional and evolutionary consequences of these and other auditory features. The dimensions of the outer ear (pinna) were measured in cadaveric specimens representing nearly every primate family and used to calculate a shape ratio (height/width). It was found that nonanthropoids have a significantly higher ratio than anthropoids, although the actual height was not found to differ. This indicates that most nonanthropoids have ears that are tall and narrow, whereas monkeys and apes are characterized by ears with more equal height and width dimensions. Eardrum area, stapedial footplate area, and ossicular lever arm lengths were measured in dried specimens to calculate an impedance transformer ratio. A distinction was found between anthropoids and strepsirrhines, with the latter group having a transformer ratio indicative of a higher percentage of acoustic energy transmission through the middle ear. Audiogram data were gathered from the literature to analyze hearing sensitivity and it was found that platyrrhines illustrate more low‐frequency sensitivity than like‐sized lorisoids. The effects of intraspecific variation on the audiogram results were also examined and were found to produce similar results as the analysis using species mean threshold values. Lastly, correlations between morphological and audiogram variables were examined. Several measures of hearing sensitivity were found to be correlated with pinna shape but correlations with middle ear transmission properties were weaker. In addition to using traditional statistical techniques, phylogenetic corrective methods were applied to address the problem of statistical nonindependence of the data and the results of both analyses are compared. These findings are discussed with respect to how sensory adaptations and phylogenetic history may be related to the current radiation of primates. © 2004 Wiley‐Liss, Inc.
Meissner corpuscles and somatosensory acuity: The prehensile appendages of primates and elephants
Authors: Hoffmann Joscelyn N. , Montag Anthony G. , Dominy Nathaniel J.
Published: October 2004

Meissner corpuscles (MCs) are specialized mechanoreceptors located exclusively in the papillae of glabrous skin. They are confined largely to cutaneous pads of the extremities and respond to transient, phasic, or vibratory stimuli. Though absent in most eutherian taxa, MCs are reported in all primates studied, being most developed in modern humans. The location of MCs between the internal ridges of the epidermis indicates they are well situated to detect friction or deformation at the external surface. Accordingly, MCs are hypothesized to provide primates generally with an enhanced tactile perception. However, the selective pressures favoring greater somatosensory acuity in primates are seldom considered. Interestingly, primate digital dexterity varies greatly. In general, dexterity improves with the extent to which foraging requires food manipulation or textural evaluation. This observation implies that MC density could vary accordingly. Here we report on the density of MCs in five anthropoid taxa selected to represent diverse dietary regimes. Results show that greater MC density correlates with the extent to which primates are frugivorous; however, locomotor and/or phylogenetic effects cannot be discounted. © 2004 Wiley‐Liss, Inc.
Evolution of somatosensory and motor cortex in primates
Authors: Kaas Jon H.
Published: October 2004

Inferences about how the complex somatosensory systems of anthropoid primates evolved are based on comparative studies of such systems in extant mammals. Experimental studies of members of the major clades of extant mammals suggest that somatosensory cortex of early mammals consisted of only a few areas, including a primary area, S1, bordered by strip‐like rostral and caudal somatosensory fields, SR and SC. In addition, the second somatosensory area, S2, and the parietal ventral area, PV, were probably present. S1, S2, and PV were activated independently via parallel projections from the ventroposterior nucleus, VP. Little posterior parietal cortex existed, and it was unlikely that a separate primary motor area, M1, existed until placental mammals evolved. Early primates retained this basic organization and also had a larger posterior parietal region that mediated sensorimotor functions via connections with motor and premotor areas. The frontal cortex included M1, dorsal and ventral premotor areas, supplementary motor area, and cingulate motor fields. Ventroposterior superior and ventroposterior inferior nuclei were distinct from the ventroposterior nucleus in the thalamus. In early anthropoid primates, areas S1, SR, and SC had differentiated into the fields now recognized as areas 3b, 3a, and 1. Areas 3b and 1 contained parallel mirror‐image representations of cutaneous receptors and a parallel representation in area 2 was probable. Serial processing became dominant, so that neurons in areas 1, S2, and PV became dependent on area 3b for activation. Posterior parietal cortex expanded into more areas that related to frontal cortex. Less is known about changes that might have occurred with the emergence of apes and humans, but their brains were larger and posed scaling problems most likely solved by increasing the number of cortical areas and reducing the proportion of long connections. © 2004 Wiley‐Liss, Inc.
Comparative analysis of the role of olfaction and the neocortex in primate intrasexual competition
Authors: Alport Laura J.
Published: October 2004

In strepsirrhine primates, the accessory olfactory system plays an important role in intrasexual competition. However, it does not play the same role in most haplorhines. In these primates, the main olfactory system and neocortex may have evolved to serve similar functions as the accessory olfactory system in strepsirrhines. To test these hypotheses, the relative size of the main olfactory bulb and neocortex were analyzed for associations with male and female competition frequency and intensity (categorized as low or high). Because neocortex size and competition intensity are associated with diet, only frugivorous species were analyzed (catarrhines, n = 7; platyrrhines, n = 8). Neither the size of the main olfactory bulb nor the neocortex was significantly associated with intrasexual competition among males. However, neocortex size was related to the frequency of female competition. Because the main olfactory system and neocortex both serve multiple purposes, there may not be a single behavioral variable that has selected for their size. Furthermore, categorization of male and female competition intensity reflects physically aggressive behavior. Use of the neocortex for social manipulation may allow males to obtain copulations and females to obtain food resources despite poor physical fighting abilities and low dominance rank. © 2004 Wiley‐Liss, Inc.
Expression of neuron‐specific markers by the vomeronasal neuroepithelium in six species of primates
Authors: Dennis John C. , Smith Timothy D. , Bhatnagar Kunwar P. , Bonar Christopher J. , Burrows Anne M. , Morrison Edward E.
Published: October 2004

Vomeronasal organ (VNO) morphology varies markedly across primate taxa. Old World monkeys display no postnatal VNO. Humans and at least some apes retain a vestigial VNO during postnatal life, whereas the strepsirrhines and New World Monkeys present a morphologically well‐defined VNO that, in many species, is presumed to function as an olfactory organ. Available microanatomical and behavioral studies suggest that VNO function in these species does not precisely duplicate that described in other mammalian taxa. The questions of which species retain a functional VNO and what functions they serve require inquiry along diverse lines but, to be functional, the vomeronasal epithelium must be neuronal and olfactory. We used immunohistochemistry to establish these criteria in six primate species. We compared the expression of two neuronal markers, neuron‐specific β‐tubulin (BT) and protein gene product 9.5, and olfactory marker protein (OMP), a marker of mature olfactory sensory neurons, in paraffin‐embedded VNO sections from two strepsirrhine and four haplorhine species, all of which retain morphologically well‐defined VNOs during postnatal life. The infant Eulemur mongoz, adult Otolemur crassicaudatus, neonatal Leontopithicus rosalia, and adult Callithrix jacchus express all three proteins in their well‐defined vomeronasal neuroepithelia. The infant Tarsius syrichta showed some BT and OMP immunoreactivity. We establish that two strepsirrhine species and at least some New World haplorhines have mature sensory neurons in the VNO. In contrast, at all ages examined, Saguinus geoffroyi VNO expresses these markers in only a few cells. © 2004 Wiley‐Liss, Inc.
Facts, fallacies, fears, and frustrations with human pheromones
Authors: Wysocki Charles J. , Preti George
Published: October 2004

Among primates in general, pheromones are of variable importance to social communication. Data on humans have generated the greatest controversy regarding the existence of pheromonal communication. In this review, the likelihood of pheromonal communication in humans is assessed with a discussion of chemical compounds produced by the axilla that may function as pheromones; the likelihood that the vomeronasal organ (VNO), a putative pheromone receptor organ in many other mammals, is functional in humans; and the possible ways pheromones operate in humans. In the human axilla, the interactions between the cutaneous microflora and axillary secretions render this region analogous to scent glands found in other primates. Both the chemistry of axillary secretions and their effects on conspecifics in humans appear to be analogous to other mammalian pheromone systems. Whichever chemical compounds serve a pheromonal function in humans, another unknown is the receptor. Although the VNO has been implicated in the reception of pheromones in many vertebrates, it is not the only pathway through which such information has access to the central nervous system; there is ample evidence to support the view that the olfactory epithelium can respond to pheromones. Furthermore, if a chemical activates receptors within the VNO, this does not necessarily mean that the compound is a pheromone. An important caveat for humans is that critical components typically found within the functioning VNO of other, nonprimate, mammals are lacking, suggesting that the human VNO does not function in the way that has been described for other mammals. In a broader perspective, pheromones can be classified as primers, signalers, modulators, and releasers. There is good evidence to support the presence of the former three in humans. Examples include affects on the menstrual cycle (primer effects); olfactory recognition of newborn by its mother (signaler); individuals may exude different odors based on mood (suggestive of modulator effects). However, there is no good evidence for releaser effects in adult humans. It is emphasized that no bioassay‐guided study has led to the isolation of true human pheromones, a step that will elucidate specific functions to human chemical signals. © 2004 Wiley‐Liss, Inc.
Convergence of sensory systems in the orbitofrontal cortex in primates and brain design for emotion
Authors: Rolls Edmund T.
Published: October 2004

In primates, stimuli to sensory systems influence motivational and emotional behavior via neural relays to the orbitofrontal cortex. This article reviews studies on the effects of stimuli from multiple sensory modalities on the brain of humans and some other higher primates. The primate orbitofrontal cortex contains the secondary taste cortex, in which the reward value of taste is represented. It also contains the secondary and tertiary olfactory cortical areas, in which information about the identity and also about the reward value of odors is represented. A somatosensory input is revealed by neurons that respond to the viscosity of food in the mouth, to the texture (mouth feel) of fat in the mouth, and to the temperature of liquids placed into the mouth. The orbitofrontal cortex also receives information about the sight of objects from the temporal lobe cortical visual areas. Information about each of these modalities is represented separately by different neurons, but in addition, other neurons show convergence between different types of sensory input. This convergence occurs by associative learning between the visual or olfactory input and the taste. In that emotions can be defined as states elicited by reinforcers, the neurons that respond to primary reinforcers (such as taste and touch), as well as learn associations to visual and olfactory stimuli that become secondary reinforcers, provide a basis for understanding the functions of the orbitofrontal cortex in emotion. In complementary neuroimaging studies in humans, it is being found that areas of the orbitofrontal cortex are activated by pleasant touch, by painful touch, by taste, by smell, and by more abstract reinforcers such as winning or losing money. Damage to the orbitofrontal cortex in humans can impair the learning and reversal of stimulus‐reinforcement associations and thus the correction of behavioral responses when these are no longer appropriate because previous reinforcement contingencies change. It is striking that humans and other catarrhines, being visual specialists like other anthropoids, interface the visual system to other sensory systems (e.g., taste and smell) in the orbitofrontal cortex. © 2004 Wiley‐Liss, Inc.
Evidence for a molecular mechanism of teratogenicity of SB‐236057, a 5‐HT1B receptor inverse agonist that alters axial formation
Authors: Augustine‐Rauch Karen A. , Zhang Qin J. , Leonard Jennifer L. , Chadderton Antony , Welsh Michael J. , Rami Harshad K. , Thompson Mervyn , Gaster Laramie , Wier Patrick J.
Published: October 2004

BACKGROUND

SB‐236057 is a potent skeletal teratogen in rodents and rabbits, producing axial and posterior somite malformations in cultured rat embryos. The compound shares some structural similarity to cyclopamine.

METHODS

M13 phage display was used to identify amino acid motifs with binding affinity to SB‐236057. A 10 μM SB‐236057 solution was administered to cultured day 9 postcoitus rat embryos and real‐time PCR was conducted at 6 hr posttreatment to evaluate early transcriptional response of axial development genes. Whole‐mount in situ hybridization of selected transcripts was conducted on embryos at 48 hr post‐compound administration. The rat‐enhancer of split protein 1 (r‐esp1) expression‐functional characterization was done by transcriptional expression and morpholino antisense approaches.

RESULTS

We identified several amino acid motifs that had high binding affinity to SB‐236057‐biotin conjugates, one with 100% sequence homology to a region of r‐esp1, one of the Groucho homologs transcribed by the enhancer of split complex (En[spl]C). SB‐236057 repressed expression of r‐esp1 and members of the Notch‐En[spl]C pathway. Goosecoid and HNF3‐β, both suspected to associate with Groucho proteins, were also responsive, although expression of another putative binding protein, engrailed‐1 (en‐1), and other en‐1 pathway members was not affected. R‐esp1 mRNA was localized along the axis and antisense inhibition produced similar somite malformations as SB‐236057 did. At 48 hr post–SB‐236057 or post–r‐esp1 antisense administration, affected embryos demonstrated unchanged sonic hedgehog (shh) expression, however HNF3‐β expression was either absent, altered, or reduced.

CONCLUSIONS

We present experimental evidence that the mechanism of SB‐236057 teratogenicity includes transcriptional alterations to the Notch1‐En[spl] pathway. In addition, alterations in HNF3‐β expression were similar to those induced by cyclopamine. The relationships between r‐esp1 with Notch1 and shh signaling pathways and potential mechanisms of SB‐236057 teratogenicity are also discussed. Birth Defects Research (Part A), 2004. © 2004 Wiley‐Liss, Inc.