bluuebunny/crossref_metadata_2025 huggingface dataset:
Hindlimb proportions, allometry, and biomechanics in old world monkeys (primates, cercopithecidae)
Authors: Strasser Elizabeth
Published: August 2005

The traditional focus on morphological rather than mechanical units has obscured some significant functional differences in the hindlimbs of primates. This paper examines the allometric and biomechanical basis for some distinctive proportional differences among pairs of morphological units in the hindlimb, and especially the foot, of cercopithecid primates. Five major conclusions are reached. First, many hindlimb dimensions scale allometrically with body mass to maintain mechanical similarity within taxonomic and locomotor groups. Therefore, the majority of traditional indices which describe the shape of the foot within cercopithecids reveal differences which are primarily a function of size. Second, the hindlimb segments in colobines, and especially in Presbytis, are relatively long, probably to enhance leaping. Third, the major distinction of terrestrial cercopithecines among the features analysed is reduction in the length of the phalanges, due to the reduced importance of grasping during locomotion and the assumption of digitigrady. Fourth, Theropithecus and male Erythrocebus have high crural indices, relative to their body masses, which can facilitate cursoriality. Female E. patas already has a high crural index as a function of its body mass. Fifth, macaques form a distinctive group among cercopithecines, characterized by relatively short hindlimbs. Relatively very short hindlimbs in Macaca fuscata and M. thibetana suggest that climatic conditions can have an added effect on the lengths of the hindlimb segments. In summary, this analysis of the lengths of the hindlimb segments relative to body size reveals taxonomic differences which are due in part to phylogeny, to differences in locomotor behavior, and to substrate use.
Tooth components of mandibular deciduous molars of Homo sapiens sapiens and Homo sapiens neanderthalensis: A radiographic study
Authors: Zilberman U. , Skinner M. , Smith P.
Published: August 2005

Tooth components of deciduous

“Deciduous” is used to conform with previous usage in this journal rather than “primary”, though this term has now been adopted in the dental literature

molars were measured from standardized radiographs of Homo sapiens sapiens and Homo sapiens neanderthalensis. Enamel height and width were greater in deciduous teeth of Homo sapiens sapiens than in Homo sapiens neanderthalensis and the differences were statistically significant (p < 0.01). Dentin height showed no significant differences between the two groups, but enamel to floor of pulp chamber and pulp height and width dimensions were significantly greater in Homo sapiens neanderthalensis. Discriminant analysis carried out between groups, using deciduous tooth components, showed an accuracy of 98–100% for identification of Homo sapiens sapiens and 83–92% for identification of Homo sapiens neanderthalensis. The results obtained in this study on dental dimensions support the hypothesis of a distinct evolutionary line for Neanderthals.
Metacarpophalangeal length changes in humans during adulthood: A longitudinal study
Authors: Harris Edward F. , Aksharanugraha Korntip , Behrents Rolf G.
Published: August 2005

Total lengths of the 19 diaphyseal hand bones were measured from standardized radiographs of healthy American whites as young adults (ca. 21 years) and again at ca. 55 years of age. The four hand‐bone rows exhibit distinctive length changes: Distal and middle phalanges continue to increase significantly in length, proximal phalanges constitute a transition zone of little change, and metacarpals uniformly decrease in length. Clear‐cut sex differences are noteworthy: Males change more (lose more in some bone rows, gain more in others) than females. Progressive elongation was greatest in the distal phalanges where apposition around the distal aspect (“tufting”) is not constrained by a joint or epiphysis. Loss of bone length in the metacarpals by subchondral resorption is consistent with documented reductions in activity levels and grip strength with age, as well as diminished joint spaces which alter loading of the joints.
Genetic structure of the population of Sicily
Authors: Rickards Olga , Biondi Gianfranco , De Stefano Gian Franco , Vecchi Francesco , Walter Hubert
Published: August 2005

Genetic heterogeneity within Sicily was investigated on the basis of ACP1, ADA, ESD, GLO1, PGD, PGM1, PGM2, SODA, ABO, and MN gene frequencies, and compared to those of other regions of Italy for which these same loci have been examined. Correspondence analysis revealed no differences within the island, at least at the provincial level, but showed genetic differentiation among Italian regions, distinctly clustering northern, central, and southern populations, respectively. These data indicate a close relationship between Sicily and southern Italy. In addition, the contribution of Middle Eastern populations to the gene pool of Sicily was evident.
Metrical reconsideration of the Skhul IV and IX and Border Cave 1 crania in the context of modern human origins
Authors: Corruccini Robert S.
Published: August 2005

The “out‐of‐Africa” models for origins of modern Homo sapiens incorporate Skhul as one site documenting that early origination. However, only Skhul V is usually considered in the comparative craniology of the question, neglecting the other substantial crania, Skhul IV and IX. Craniometric comparison demonstrates that IV and IX amplify the picture of continuous gradations of Neandertal‐to‐modern variations throughout the Levant; much variation is thus represented within this one site, raising serious questions about Neandertals and moderns being discrete and long‐separated species. Qafzeh 6 too is craniophenetically closer to Neandertals than to the true anatomically modern people of the European Upper Paleolithic. Proper distance analysis of Border Cave 1 cranium shows it is actually far removed from modern African populations. References to Qafzeh, Skhul, and Border Cave as “fully anatomically modern” require reconsideration.
Testicle size of orang‐utans in relation to body size
Authors: Dahl Jeremy F. , Gould Kenneth G. , Nadler Ronald D.
Published: August 2005

Few data are available for assessing the relative testicle size of orang‐utans, Pongo pygmaeus, so measures were obtained for 31 individuals of varying age. It was shown that the volume of the testicles, calculated from in situ measures of testicle length and breadth, closely approximates testicle weight when multiplied by the specific gravity of solid tissue. Growth curves for body weight and data published for wild specimens were evaluated to obtain the weight most characteristic of male Pongo, and the ratio of testicle weight to body weight was calculated. The mean ratio for individuals with fully adult stature is 0.034, similar to but smaller than that of humans at about 0.050, and larger than the ratios reported for 5 gorillas at 0.013. The testicles mature faster than the body, however, so the mean ratio for young adult orang‐utans is about 0.056 and resembles the ratio for humans more closely than the full adults. The differences between the ratios for a monogamous gibbon species, orang‐utans, and humans is accounted for when testicle size relative to the weight of the female is considered. This is consistent with a sperm dilution effect produced by variation in the size of the female reproductive tract. The small relative testicle size of the gorilla is anomalous and requires verification as does the application of female size to scale the testicles. © 1993 Wiley‐Liss, Inc.
Stature reconstruction from long bones in ancient population samples: An approach to the problem of its reliability
Authors: Formicola Vincenzo
Published: August 2005

Stature estimates provided by the application of the anatomical method of Fully and Pineau (1960) to well preserved Neolithic skeletons (39 males and 27 females) from seven different European countries are compared with those drawn from lower‐extremity components by means of regression equations commonly used to predict stature of earlier European populations. The analysis of data, carried out with reference both to the sample of origin of the skeletons adn to stature classes, suggests that the equations of Pearson (1899) and of Trotter and Gleser for Negroes (1952, 1977) yield very good estimates in female samples, leading to errors below 2 cm in most of the cases. These equations, and those of Olivier et al. (1978), prove useful for stature reconstruction in males too, with the exception of very low (below 154 cm) and very tall (over 179 cm) individuals. Formulae of Breitinger (1938) yield values consistent with those resulting from the anatomical method only within a range including medium‐high statures, while the coresponding Bach (1965) formulae for females provide poor approximations. The Trotter and Gleser formulae for Whites (1952) yield very unsatisfactory evaluations, except in specimens taller than 180 cm, and usually overestimate stature both in male and in female skeletons.

The results obtained from the long bones by means of alternative approaches to the least‐squares regression formulae (Model II regression, and femur/stature ratio) and their efficacy in predicting stature of the samples under study is discussed in the final part of the paper. © 1993 Wiley‐Liss, Inc.
Postcranial robusticity in Homo. II: Humeral bilateral asymmetry and bone plasticity
Authors: Trinkaus Erik , Churchill Steven E. , Ruff Christopher B.
Published: August 2005

The analysis of humeral asymmetry in Recent human skeletal samples and an extant tennis‐player sample documents minimal asymmetry in bone length, little asymmetry in distal humeral articular breadth, but pronounced and variable asymmetry in mid‐ and distal diaphyseal crosssectional geometric parameters. More specifically, skeletal samples of normal modern Euroamericans, prehistoric and early historic Amerindians, and prehistoric Japanese show moderate (ca. 5–14%) median asymmetry in diaphyseal cross‐sectional areas and polar second moments of area, whereas the tennis‐player sample, with pronounced unilateral physical activity, exhibits median asymmetries of 28–57% in the same parameters. A sample of Neandertals with nonpathological upper limbs exhibits similarly low articular asymmetry but pronounced diaphyseal asymmetries, averaging 24–57%. In addition, three Neandertals with actual or possible post‐traumatic upper limb alterations have the same low articular asymmetry but extremely high diaphyseal asymmetries, averaging 112–215%. These data support those from experimental work on animals, exercise programs of humans, and human clinical contexts in establishing the high degree of diaphyseal plasticity possible for humans, past and present, under changing biomechanical loading conditions. This lends support to activity‐related functional interpretations of changing human diaphyseal morphology and robusticity during the Pleistocene. © 1994 Wiley‐Liss, Inc.
Metatarsophalangeal joint function and positional behavior in Australopithecus afarensis
Authors: Duncan Alexander S. , Kappelman John , Shapiro Liza J.
Published: August 2005

Recent discussions of the pedal morphology of Australopithecus afarensis have led to conflicting interpretations of australopithecine locomotor behavior. We report the results of a study using computer aided design (CAD) software that provides a quantitative assessment of the functional morphology of australopithecine metatarsophalangeal joints. The sample includes A. afarensis, Homo sapiens, Pan troglodytes, Gorilla gorilla, and Pongo pygmaeus. Angular measurements of the articular surfaces relative to the long axes of the metatarsals and phalanges were taken to determine whether the articular surfaces are plantarly or dorsally oriented. Humans have the most dorsally oriented articular surfaces of the proximal pedal phalanges. This trait appears to be functionally associated with dorsiflexion during bipedal stride. Pongo has the most plantarly oriented articular surfaces of the proximal pedal phalanges, probably reflecting an emphasis on plantarflexion in arboreal positional behaviors, while the African hominoids are intermediate between Pongo and Homo for this characteristic. A. afarensis falls midway between the African apes and humans. Results from an analysis of metatarsal heads are inconclusive with regard to the functional morphology of A. afarensis. Overall, the results are consistent with other evidence indicating that A. afarensis was a capable climber. © 1994 Wiley‐Liss, Inc.
Developmental, diachronic, and demographic analysis of cribra orbitalia in the medieval christian populations of Kulubnarti
Authors: Mittler Diane M. , van Gerven Dennis P.
Published: August 2005

Previous analysis of cribra orbitalia in the medieval populations of Kulubnarti focused only on the presence or absence of the lesion relative to age, sex, and cultural period. Demographic consideration of the lesion was limited to a gross comparison of lesion frequencies and probabilities of dying by age group. The scope of the earlier work has been expanded in the present research to include the consideration of cribra orbitalia from a developmental, demographic, and diachronic perspective.

The sample consisted of the same 334 crania analyzed by Van Gerven et al. ([1981] J. Hum. Evol. 10:395–408). All skulls showing the lesion were dichotomized as active or healing, and separate life tables were constructed for those with lesions and those without.

The results demonstrate that active lesions are confined entirely to infancy and childhood with formation beginning as early as six months and ending by the twelfth year. This childhood pattern is consistent with the iron deficiency anemia hypothesis proposed by Carlson et al. ([1974] J. Hum. Evol. 3:405–410). Among young adults (16–40), healing lesions occur more frequently in males than females. In the older age categories, however, females exhibit a higher frequency of partially healed lesions than males.

A life table comparison of those with and those without cribra orbitalia reveals a dramatic reduction in mean life expectancy for those with the lesion across the formative childhood years (birth‐16). This reduction peaks at age 5 where 78% of the children exhibit lesions and where they, as a group, have a mean life expectancy 15.5 years below those without the lesion. © 1994 Wiley‐Liss, Inc.
Longitudinal analysis of adolescent growth in height, fatness, and fat patterning in rural South African black children
Authors: Cameron N. , Gordon‐Larsen P. , Wrchota E. M.
Published: August 2005

Adolescent growth in height, fatness, and fat patterning was investigated in a sample of 79 rural South African black children studied longitudinally from 6–18 years. Data were analyzed relative to peak height velocity (PHV) to identify the phenomenon of “compensatory” growth in height during adolescence and to describe changes in fatness and fat patterning. Compensatory growth following PHV was clearly observed relative to NHANES data for African‐Americans in that Z‐scores for height at the start of the adolescent growth spurt were greater than those at the end of the spurt. Statistically significant differences in fatness and centralization between males and females did not occur until about 2 years after PHV was attained. Centralization of fat occurred in both sexes but moreso in males. The lack of centralization in females was due to relatively greater triceps skinfold velocities. The rapid gain in post‐PHV fatness in females may represent a physiological adaptation to an energetically sub‐optimal environment, buffering the energetic costs of reproduction. © 1994 Wiley‐Liss, Inc.
New early Eocene anaptomorphine primate (Omomyidae) from the Washakie Basin, Wyoming, with comments on the phylogeny and paleobiology of anaptomorphines
Authors: Williams Blythe A. , Covert Herbert H.
Published: August 2005

Recent paleontological collecting in the Washakie Basin, southcentral Wyoming, has resulted in the recovery of over 100 specimens of omomyid primates from the lower Eocene Wasatch Formation. Much of what is known about anaptomorphine omomyids is based upon work in the Bighorn and Wind River Basins of Wyoming. This new sample documents greater taxonomic diversity of omomyids during the early Eocene and contributes to our understanding of the phylogeny and adaptations of some of these earliest North American primates. A new middle Wasatchian (Lysitean) anaptomorphine, Anemorhysis savagei, n. sp., is structurally intermediate between Teilhardina americana and other species of Anemorhysis and may be a sister group of other Anemorhysis and Trogolemur.

Body size estimates for Anemorhysis, Tetonoides, Trogolemur, and Teilhardina americana indicate that these animals were extremely small, probably less than 50 grams. Analysis of relative shearing potential of lower molars of these taxa indicates that some were primarily insectivorous, some primarily frugivorous, and some may have been more mixed feeders. Anaptomorphines did not develop the extremes of molar specialization for frugivory or insectivory seen in extant prosimians. Incisor enlargement does not appear to be associated with specialization in either fruits or insects but may have been an adaptation for specialized grooming or food manipulation. © 1994 Wiley‐Liss, Inc.
Terrestrial adaptations in the postcranial skeletons of guenons
Authors: Gebo Daniel L. , Sargis Eric J.
Published: August 2005

Arboreal and semiterrestrial guenons show similar osteological features of the limbs across a wide range of species, environments, and geography, while the more terrestrially committed guenons exhibit greater morphological divergence. An ecomorphological comparison of two sympatric guenons living in Kibale Forest, Uganda, reveals an array of anatomical adaptations for terrestriality in the limbs of Cercopithecus lhoesti similar to those found in Erythrocebus patas. In contrast, Cercopithecus aethiops, although also frequent users of the terrestrial environment, generally exhibit fewer morphological adaptations characteristic of a terrestrial lifestyle. It appears that significant morphological modification for terrestriality has occurred twice within the diverse radiation of living guenons with C. aethiops perhaps representing a third group in the making. © 1994 Wiley‐Liss, Inc.
Average menarcheal age of higher socioeconomic status urban Cape Coloured girls assessed by means of status quo and recall methods
Authors: Henneberg M. , Louw G. J.
Published: August 2005

The age of the onset of menstruation has been determined for the urban middle‐class Cape Coloured population. From 1987 to 1992 data were collected from 857 girls aged 8 to 20 years attending primary and secondary schools in Cape Town. The schools were specifically selected for the highest socioeconomic status (SES) of pupils' parents. Three‐quarters of parents fell into the higher three categories of the 5‐category SES standard. Girls were interviewed with respect to their menarcheal status and those who were postmenarcheal were also asked to report when they had started to menstruate. The probit analysis of the status quo data yielded average of 12.61 years and a standard deviation (s) of 1.25 years. The retrospective method was applied only to recall data of 258 girls falling into fully postmenearcheal categories (16–20 years). It yielded an average of 12.75 (s = 1.32), insignificantly different from that obtained from the probit analysis. The menarcheal age of higher SES Cape Coloured girls is significantly lower than that of white girls in Cape Town (13.30 years) and much lower than that of any group of black South African girls. It falls close to the lower limit of the range reported worldwide. Body heights, weights, and Body Mass Index indicate good growth status of girls studied.
Hominid fossil sample from Kanjera, Kenya: Description, provenance, and implications of new and earlier discoveries
Authors: Plummer Thomas , Potts Richard
Published: August 2005

Anatomically modern hominids were first collected from Kanjera, Kenya, by L.S.B. Leakey in the 1930s. Their apparent association with an archaic fauna was quickly challenged, throwing their age into doubt. Further unpublished hominid fragments were collected in 1974, 1975, 1981, and 1987. We review the context and morphology of the entire hominid sample. A minimum number of five individuals is represented by both cranial and postcranial elements. Several individuals have thickened cranial vaults, a characteristic originally thought to reflect their great antiquity. Vault thickening resulted from diploic expansion and may have been a response to acquired or inherited anemia. The entire hominid sample postdates the Kanjera Formation, deposited from the early into the middle Pleistocene. Most of the sample was derived from the black cotton soil capping the stratigraphic column. The morphology and context of the Kanjera hominids is consistent with human skeletal remains from nearby Holocene sites. Hominid 3 was probably an intrusive burial into an early Pleistocene bed. © 1995 Wiley‐Liss, Inc.
Anthropometric variation and the population history of Ireland
Authors: Relethford John H. , Crawford Michael H.
Published: August 2005

Genetic variation among human populations can reflect a combination of contemporary patterns of gene flow and genetic drift as well as long‐term population relationships due to population history. We examine the likely impact of past history and contemporary structure on the patterns of anthropometric variation among 31 counties in Ireland (made up of the two nations of the Republic of Ireland and Northern Ireland). Data for 17 anthropometric measures and parent‐offspring migration on 7,214 adult Irish males were taken from the large data set originally collected by Dupertuis and Dawson in the mid‐1930s (Hooton et al., 1955). Patterns of genetic similarity among 31 counties were assessed using R matrix methods that allow estimation of minimum genetic distances. These distances were compared to distances reflecting history, geography, and migration using matrix permutation methods. The results indicate that among‐group variation in Ireland reflects past population history to a much greater extent than contemporary patterns of migration and population size. The midland counties are distinct from other populations, and their history suggests greater genetic input from early Viking invasions. A second major pattern in biological variation is a longitudinal gradient separating western and eastern counties. This gradient appears related to patterns of early settlement and/or a concentration in the east of later immigrants, particularly from England. Comparison of regional means with published data for several other European nations confirms these hypotheses. © 1995 Wiley‐Liss, Inc.
Indo‐European origins: A computer‐simulation test of five hypotheses
Authors: Barbujani Guido , Sokal Robert R. , Oden Neal L.
Published: August 2005

Allele frequency distributions were generated by computer simulation of five models of microevolution in European populations. Genetic distances calculated from these distributions were compared with observed genetic distances among Indo‐European speakers. The simulated models differ in complexity, but all incorporate random genetic drift and short‐range gene flow (isolation by distance). The best correlations between observed and simulated data were obtained for two models where dispersal of Neolithic farmers from the Near East depends only on population growth. More complex models, where the timing of the farmers' expansion is constrained by archaeological time data, fail to account for a larger fraction of the observed genetic variation; this is also the case for a model including late Neolithic migrations from the Pontic steppes. The genetic structure of current populations speaking Indo‐European languages seems therefore to largely reflect a Neolithic expansion. This is consistent with the hypothesis of a parallel spread of farming technologies and a proto‐Indo‐European language in the Neolithic. Allele‐frequency gradients among Indo‐European speakers may be due either to incomplete admixture between dispersing farmers, who presumably spoke proto‐Indo‐European, and pre‐existing hunters and gatherers (as in the traditional demic diffusion hypothesis), or to founder effects during the farmers' dispersal. By contrast, successive migrational waves from the East, if any, do not seem to have had genetic consequences detectable by the present comparison of observed and simulated allele frequencies. © 1995 Wiley‐Liss, Inc.
Reconstruction of the STS 14 (Australopithecus africanus) pelvis
Authors: Abitbol M. Maurice
Published: August 2005

The study reports a reconstruction of the sacrum in STS 14 based on extrapolation from the measurements of the first two sacral vertebrae of STS 14 and of the angle formed by the anterior surfaces of their vertebral bodies. Reconstruction is based on comparisons of, and extrapolation from, sacra of Pan troglodytes, Homo sapiens, and Australopithecus afarensis. The reconstructed sacrum has an anterior sacral curvature of 39°. The two ossa coxae were also completed by mirror imaging of one side by the other. With the pelvis completely reconstructed, the pelvic dimensions for the antero‐posterior (AP) diameters of the pelvic inlet, midpelvis, and pelvic outlet are 85, 68, and 69 mm and the corresponding transverse (TR) diameters are 109, 88, and 103 mm, respectively. The posterior sagittal diameters in the three pelvic planes are small compared to the anterior sagittal diameters. This analysis indicates that the STS 14 pelvis is platypelloid in the three pelvic planes; i.e., all the AP diameters are smaller than the corresponding TR diameters. This makes the STS 14 pelvis similar to that to Al 288‐1, save for a less pronounced degree of platypelloidy at the inlet in the former. © 1995 Wiley‐Liss, Inc.
Nonlinearity in the relationship between bone Sr/Ca and diet: Paleodietary implications
Authors: Burton James H. , Wright Lori E.
Published: August 2005

Strontium in archaeological human bones is widely, almost paradigmatically, used as a measure of the relative dietary abundances of plants and meat. Quantitative modeling reveals, however, that there is not a simple proportional relationship between bone strontium and the dietary plant/meat ratio. While knowledge of specific foods and their compositions may permit accurate calculation of average bone strontium levels, knowledge of bone strontium does not inversely allow accurate calculation of specific foods. Although bone strontium quantitatively reflects the average dietary Sr/Ca ratio, it is disproportionately sensitive to high‐calcium foods and can be easily affected by minor dietary constituents and culinary practices. Bone strontium, and by analogy, barium, should be seen as a reflection of the high‐mineral dietary components rather than a quantitative index of trophic position. © 1995 Wiley‐Liss, Inc.
Enamel hypoplasia in the Middle Pleistocene hominids from Atapuerca (Spain)
Authors: De Castro José M. Bermédez , Pérez Pilar Julia
Published: August 2005

The prevalence and chronology of enamel hypoplasias were studied in a hominid dental sample from the Sima de los Huesos (SH) Middle Pleistocene site at the Sierra de Atapuerca (Burgos, northern Spain). A total of 89 permanent maxillary teeth, 143 permanent mandibular teeth, and one deciduous lower canine, belonging to a minimum of 29 individuals, were examined. Excluding the antimeres (16 maxillary and 37 mandibular cases) from the sample, the prevalence of hypoplasias in the permanent dentition is 12.8% (23/179), whereas the deciduous tooth also showed an enamel defect. No statistically significant differences were found between both arcades and between the anterior and postcanine teeth for the prevalence of hypoplasias. In both the maxilla and the mandible the highest frequency of enamel hypoplasias was recorded in the canines. Only one tooth (a permanent upper canine) showed two different enamel defects, and most of the hypoplasias were expressed as faint linear horizontal defects. Taking into account the limitations that the incompleteness of virtually all permanent dentitions imposes, we have estimated that the frequency by individual in the SH hominid sample was not greater than 40%. Most of the hypoplasias occurred between birth and 7 years (N = 18, X = 3.5, SD = 1.3). Both the prevalence and severity of the hypoplasias of the SH hominid sample are significantly less than those of a large Neandertal sample. Furthermore, prehistoric hunter‐gatherers and historic agricultural and industrial populations exhibit a prevalence of hypoplasias generally higher than that of the SH hominids. Implications for the survival strategies and life quality of the SH hominids are also discussed. © 1995 Wiley‐Liss, Inc.
Estimation of adult stature from the calcaneus and talus
Authors: Holland Thomas Dean
Published: August 2005

Calcanei and tali of 100 skeletons in the Hamann–Todd Collection at the Cleveland Museum of Natural History were measured. The skeletons represented 50 males and 50 females distributed equally by race, i.e., whites and blacks. Linear‐regression equations, with standard errors ranging from 4.09 to 6.11 cm, were derived from these measurements for the purpose of estimating stature. Two independent control samples, including one comprised of remains of American servicemen lost in World War II and the Korea and Vietnam wars, were tested with relatively accurate results. © 1995 Wiley‐Liss, Inc.
Structure and size of bronchopulmonary anastomoses in sheep lung
Authors: Bernard Susan , Luchtel Dan L. , Polissar Nayak , Hlastala Michael P. , Lakshminarayan S.
Published: August 2005

The distribution and drainage of bronchial arterial blood flow are complex. We used two different methods to study the bronchial‐pulmonary anastomoses in sheep lung. Initially, we injected two different sizes of fluorescent microspheres (15 and 100 μm diameter) into the bronchial artery and histologically determined where the different‐size microspheres were entrapped in the lung. In a second series of animals, we injected Microfil into the bronchial artery to observe the anastomotic vessels. The microsphere data confirmed the existence of bronchial‐to‐pulmonary anastomoses. No microspheres were found in the systemic organs (heart and kidney), confirming the absence of large bronchial artery‐to‐pulmonary vein anastomoses. Unexpectedly, proportionately more large microspheres (100 μm) lodged in the alveolar parenchyma when compared to 15 μm microspheres. This suggests that there are many more small bronchial (< 100 μm) arterioles feeding the airway mucosa than the larger anastomotic vessels feeding into the parenchyma. In the Microfil cast lungs, we observed four types of anastomotic vessels: bronchial arteries/arterioles that anastomose with pulmonary arteries/arterioles that accompany airways; bronchial arterioles that anastomose directly with parenchymal (and eventually alveolar) vessels; bronchial arterioles that anastomose with blood vessels that do not accompany airways; and bronchial arterioles that anastomose with bronchial veins. Based on our in vivo microsphere data, the vessels that do not accompany the airways are most likely bronchial venules, not pulmonary venules. © 2005 Wiley‐Liss, Inc.
Accessory joints between basiocciput and atlas/axis in the median plane
Authors: von Lüdinghausen M. , Fahr M. , Prescher A. , Schindler G. , Kenn W. , Weiglein A. , Yoshimura K. , Kageyama I. , Kobayashi K. , Tsuchimochi M.
Published: August 2005

To explore the many osseous irregularities that are found in the area between the basiocciput, the anterior arch of the atlas and the tip of the dens axis we studied 99 cadaver specimens using magnetic resonance tomography (MRT), computed tomography (CT), median saw‐cut sections, and histological sections. Additionally, “dry” specimens of the skull (n = 110), atlas (n = 56), and axis (n = 33) were investigated. In the median plane, the dry and cadaver specimens exhibited osteoarthritis‐related osseous outgrowths and osteophytes of the articular surfaces of the median atlanto‐axial joint (n = 63), and the presence of congenitally developed free ossicles (n = 22) and of third occipital condyles (n = 3). The largest osteophytes (giant osteophytes) (n = 4) of the anterior arch of the atlas formed osseous contact zones with the basiocciput that were visible histologically as real joints and were designated accessory median atlanto‐occipital joints. The third occipital condyles also formed osseous contact zones, visible histologically as real joints, with the anterior arch of the atlas or with the tip of the dens, and were designated accessory atlanto‐occipital or occipito‐odontoid joints. Frequent free ossicles, incorporated into the accessory joint, were found by histological examination to be covered with hyaline cartilage. Clin. Anat. 18:558–571, 2005. © 2005 Wiley‐Liss, Inc.
The separation of lecithin and soya oil in a countercurrent column by near critical fluid extraction
Authors: Peter Siegfried , Weidner Eckhard , Schneider Michael , Ziegelitz Rüdiger
Published: August 2005

The present contribution illustrates a way of developing a continuous separation process for near critical fluid extraction, on the example of separation of soya oil from lecithin. First, a suitable solvent was selected. Phase equilibria were measured in autoclaves. Operating conditions for a pilot plant were derived from the phase equilibrium data. The pilot plant experiments provided the necessary data for designing a production plant. Computer programs for phase equilibrium, stage to stage and mass and heat balance calculations were used in order to minimize the number of experiments. A production plant with a capacity of 500 t/a of raw lecithin was designed on the basis of experimental and computational results. A cost estimation, based on tenders, showed that it is more economical to produce lecithin by near critical fluid extraction than by conventional acetone extraction.
Reaction models for simulation of the oxidation of carbon monoxide in turbulent diffusion flames
Authors: Bockhorn Henning , Lutz Gerald
Published: August 2005

The oxidation of carbon monoxide by air in a turbulent flow was investigated under experimental conditions where the rates of turbulent mixing and of chemical reaction are comparable. For this purpose, carbon monoxide was admixed into the completely burnt gas of a natural gas flame operated with excess of air. Measurements of mean values of axial velocity, temperature and volume fractions of carbon monoxide and oxygen were compared with computational simulations involving the k – ϵ turbulence model and several turbulent reaction models for the oxidation of carbon monoxide. The comparison of measurements and numerical calculations demonstrated that the k – ϵ turbulence model is suitable for prediction of the turbulent flow field in the flow system investigated. Furthermore, it could be shown that one‐variable turbulent reaction models, such as the flamesheet or the eddy‐break‐up model, cannot explain the measured carbon monoxide volume fraction profiles. Two‐variable turbulent reaction models with a probability density function closure of the source term of the transport equation for the mass fraction of the chemical species result in a better agreement between the measured and simulated volume fraction profiles, particularly in predicting the clear influence of the initial temperature on carbon monoxide volume fractions. Weighting of the kinetic rate expression for the oxidation of carbon monoxide with different presumed probability density functions yields slightly different predictions of the carbon monoxide volume fractions, reflecting the assumed different character of turbulent fluctuations.
A new method for the prediction of liquid pulsed sieve‐tray extractors
Authors: Pietzsch Wolfgang , Blass Eckhart
Published: August 2005

As a part of a research project on the mass transfer in liquid pulsed sieve‐tray extraction columns (PSE), the diameters and hold‐ups of the drops were measured: the drop size using a suction technique, with photoelectric detection, which was adapted to the special boundary conditions of the PSE; the integral hold‐up by the pressure difference between the lower and upper parts of the column. Since experimental results cannot be described by known calculation formulae for the Sauter mean diameter and the hold‐up, a new method of calculation was developed. It is phenomenologically based on high‐speed photographs of the drop motion on a sieve tray. The mathematical‐physical model allows the prediction of drop size and hold‐up within certain limits, while the possible different operating regimes of the PSE, i.e. the mixer‐settler and dispersion regimes can also be estimated.
Distillation columns with vertical partitions
Authors: Kaibel Gerd
Published: August 2005

Distillation columns with vertical partitions can separate a feed mixture into 3 or 4 pure fractions. Compared to other column arrangements, their investment costs and energy consumption are lower. Production columns show good results and are easily controlled. Conventional distillation columns produce only 2 pure product streams at the top and at the bottom of the column. Side products are contaminated by light or heavy components, depending on the location of the side stream in the rectifying or stripping section. This disadvantage is set aside by using a distillation column with a vertical partition. The internal separation wall prevents lateral mixing of liquid and vapour in the central part of the column, forming there separate feed and outlet sections. In the presence of a vertical partition, 3 or 4 pure fractions can be obtained in a single distillation step. This is particularly advantageous when heat sensitive components are to be separated. On account of good thermodynamic properties, the energy consumption is 20 to 35% lower than that of other distillation arrangements. The control behaviour is similar or better than that of conventional distillation columns.
Fouling of heat transfer surfaces
Authors: Bohnet Matthias
Published: August 2005

Fouling and/or scaling of heat transfer surfaces causes serious problems in industry. Prevention of fouling is therefore essential for technical (considerable deterioration of heat transfer) and also economic reasons (increased costs). In order to provide successful countermeasures, it is, however, necessary to obtain more detailed information on the physical, chemical and biological processes which produce fouling. Based on the already known fouling mechanisms, it is shown that a satisfactory prediction of fouling behaviour of heat exchangers is not yet possible. This contribution presents a physical model for the description of fouling, caused by sedimentation and crystallization. It is assumed that, during fouling, deposition and removal processes overlap. In order to verify the theoretical considerations, experiments were carried out on a test rig, which could also be used for field experiments. Aqueous CaSO4 solutions served as experimental liquids. A comparison of experimental and calculated fouling factors shows a satisfactory agreement.
Computer‐aided design of tube‐bundle heat exchangers
Authors: Rümmer Peter
Published: August 2005

Based on a paper by Hein, a dimensioning program for tube‐bundle heat exchangers with straight tubes and fixed tube sheets has been developed. The equipment to be dimensioned is tested at 14 critical points, with regard to permissible stresses. The optimum thickness of the tube sheet, the shell and channel are subsequently selected on the basis of economic criteria. Compared to dimensioning according to AD‐data sheet, it is possible to save between 10 and 25% of production costs. With the aid of a finite‐element (FE) program, complex structures such as heat exchangers can be calculated accurately. Several mesh‐generation programs were written for the data input. The structure of a tube‐bundle heat exchanger with straight tubes is generated with 3/D elements with only some geometrical data. An FE‐calculation of a heat exchanger is explained with the aid of an example and stress analysis is presented.
Microbial desulphurization of coal – development and application of a slurry reactor
Authors: Höne Hans‐Jürgen , Beyer Michael , Ebner Hans G. , Klein Jürgen , Jüntgen Harald
Published: August 2005

Microbial desulphurization of coal by pyrite oxidizing enrichment cultures containing predominantly Thiobacillus ferrooxidans was performed in an air‐agitated slurry reactor, 20 l in volume. A model of microbiological and chemical reactions, occurring at various points within the coal, was set up taking into account the pore structure of the coal. The influence of parameters relevant to industrial processes, such as superficial gas velocity, particle size, initial pyrite concentration, and slurry density of the coal, on the conversion of pyrite was examined. Variation of the superficial gas velocity in the range of 0.01 to 0.04 m/s confirmed that the reaction is not controlled by oxygen transfer from gaseous to liquid phase. The rate of pyrite oxidation depends mainly on the accessibility of pyrite to micro‐organisms which is determined by the particle size of the coal as well as the distribution of pyrite crystals in the coal matrix. The accessibility of pyrite to the micro‐organisms is described by the ratio of effective to maximum microbial activity, measured as oxygen consumption. Starting with higher initial concentration of pyrite in the coal increases the oxidation rate, according to first order kinetics. Enhanced slurry densities lead to a decrease of pyrite conversion, in spite of higher pyrite concentration. The maximum pyrite oxidation rate was measured at 15% (v/v) slurry density and 25°C as 1800 mg Spyr/kg coal per day, or 360 mg Spyr/l reactor volume per day.
Gas/liquid interfacial area per unit volume and volumetric mass transfer coefficient in stirred slurry reactors
Authors: Schmitz Michael , Steiff Artur , Weinspach Paul‐Michael
Published: August 2005

In three‐phase systems, where the liquid constitutes the continuous phase, solid is the catalyst and gas represents the dispersed phase, there are decisive criteria which have to be observed in reactor design. These are e.g. the interfacial area per unit volume between gas and liquid, the volumetric mass transfer coefficient and the mass transfer coefficient. The basic aim of the present work was therefore the investigation of these parameters in relation to the main influencing parameters. Process parameters stirrer speed and superficial gas velocity were varied as well as the physical properties such as liquid viscosity, solids concentration, particle diameter and a geometrical parameter, i.e. reactor diameter. The sulphite method was employed for the determination of these values. The test results confirmed the known relationships of power consumption and superficial gas velocity. An increase in the liquid viscosity leads to a decrease in all the tested values. In most cases, suspended solid particles lead to a lowering of the test values. The influence of the tank diameter on the plots of the test values against specific power consumption turned out to be invariant so that a scale‐up of geometrically similar systems can be carried out at constant power consumption, superficial gas velocity and liquid viscosity.
Desorption delay in gas/liquid systems during vessel top venting
Authors: Friedel Lutz
Published: August 2005

During the sudden unheated vessel top venting of initially saturated two‐component gas/liquid mixtures, in which the gas is also extensively dissolved in the non‐evaporating liquid phase, a solubility inequilibrium develops between the phases; re‐equilibration can set in only after a so‐called desorption delay time. Laboratory measurements of this delay time were under‐taken with model mixtures of CO2 and water and viscous aqueous (Newtonian) solutions by high speed cinematography. The parameters of the experiments are relief cross‐section, initial liquid level, pressure, temperature, and concentration. The shortest deley time obtained lasts approximately 75 ms. It differs substantially from the minimum boiling delay time previously measured with various refrigerants in the same test facility. The experimental results are correlated by a semi‐empirical dimensionless power relationship, which includes all independent primary design variables generally availble in a physically consistent interrelationship. Reasonable extrapolations to other test conditions and aqueous two‐component systems with an acceptable accuracy systems can therefore be expected.
Pressure drop and flooding in packed columns operating at high pressures
Authors: Krehenwinkel Helmut , Knapp Helmut
Published: August 2005

Correlations for pressure drop and upper capacity limit (flooding) are useful for the design of packed columns. Available correlations are based on the results of measurements made at atmospheric pressure. Extrapolation to higher pressures is not recommended. Therefore, systematic experimental investigations were carried out in a pilot plant at pressures of up to 100 bar. The experimental equipment and techniques, evaluation methods, and some characteristic experimental results are presented.
Steam reforming of natural gas with intergrated hydrogen separation for hydrogen production
Authors: Oertel Michael , Schmitz Johannes , Weirich Walter , Jendryssek‐Neumann Ditmar , Schulten Rudolf
Published: August 2005

The development of heat resistant permeation membranes has opened up new possibilities for the conversion of fossil energy resources. In steam reforming of natural gas, such membranes even permit a direct production of hydrogen at high temperatures during the conversion of feed hydrocarbons. Further gas processing, such as required for reformer gas in existing hydrogen production processes, is not necessary. Due to continuous hydrogen discharge directly in the reformer tube, the chemical equilibrium of the occurring reactions becomes displaced towards the products, resulting in more favourable process conditions and, consequently, in improved by 36% utilization of the feed hydrocarbons. At the same time, the hydrogen yield increases by 44%. The heat required, which is provided by a high temperature reactor, is 17% in excess of that in conventional plants. It can be expected that the simplified process design will produce substantial cost advantages over the existing processes for the production of hydrogen.
Chemical technology of natural gas – its present state and prospects
Authors: Preuß Ulrike , Baerns Manfred
Published: August 2005

Against the background of long‐term availability of natural gas, its present technology and future prospects are described. Particular emphasis is put on the oxidative coupling of methane to C2+hydrocarbons: (1) Catalyst development, activity, selectivity and deactivation as well as reactor operation are discussed; (2) a tentative process scheme is put forward and its economics evaluated with respect to ethylene production.