Age-related changes of bone mineral density in human calcaneus, talus, and scaphoid bone

To examine whether the bone mineral density (BMD) decreases uniformly with aging in any spongy bones, the authors investigated age-related changes of BMD in the calcaneus, talus, and scaphoid bone. After the ordinary dissection by medical students was finished, calcanei, tali, and scaphoid bones were resected from the subjects, and BMDs were measured by dual-energy X-ray absorptiometry. Their BMDs seemed to decrease gradually with aging in the calcanei, tali, and scaphoid bones. It was found that there were statistically significant relationships between age and BMD in the men’s and women’s scaphoid bones, women’s tali, and women’s calcanei, but not in the men’s tali and calcanei. It should be noted that there were significant relationships between age and BMD in both men’s and women’s scaphoid bones. In regard to relationship in BMD between the bones of the upper and lower limbs in individuals, it was found that the relationship between the calcaneus and talus was higher than that between the calcaneus and scaphoid bone. This suggests that there is a higher relationship in BMD between the two tarsal bones compared with that between the tarsal and carpal bones.     

Morphometrics of the Neandertal talus.

A number of morphometric analyses of Neandertal tali since the turn of the century have failed to reach a consensus on the functional affinities of these fossil foot bones. To clarify the problem a univariate and multivariate analysis of the available Neandertal and Skhūl tali in relation to those of modern humans was performed using nine linear dimensions and four angles. Our analysis indicates that Neandertal tali are indistinguishable from modern human tali in the implied locomotor capabilities and similar in overall size and proportions. The primary differences between the fossil and modern tali involve the greater articular robustness of the fossils, probably to compensate for higher levels of biomechanical stress.     

Some African fossil foot bones: a note on the interpolation of fossils into a matrix of extant species

Certain fossil foot bones (a terminal toe phalanx from Olduvai, specimens of tali from Spy, Skhūl, Olduvai, Kromdraai, Songhor and Rusinga) have been investigated by other workers using the multivariate statistical approach. The conclusions of their studies have, in the main, been based upon examination of early canonical variates alone. It is demonstrated here that if the full analyses (generalized distances) are taken into account, then almost exactly opposite conclusions obtain. The terminal toe phalanx from Olduvai is widely different from those of modern men; the Neandertal tali differ more from modern human bones than previously realized; the specimens from Olduvai, Kromdraai, Songhor and Rusinga are all completely dissimilar from both African ape and modern human tali.     

Human talus bones from the Middle Pleistocene site of Sima de los Huesos (Sierra de Atapuerca,Burgos, Spain)

Here we present and describe comparatively 25 talus bones from the Middle Pleistocene site of the Sima de los Huesos (SH) (Sierra de Atapuerca, Burgos, Spain). These tali belong to 14 individuals (11 adult and three immature). Although variation among Middle and Late Pleistocene tali tends to be subtle, this study has identified unique morphological characteristics of the SH tali. They are vertically shorter than those of Late Pleistocene Homo sapiens, and show a shorter head and a broader lateral malleolar facet than all of the samples. Moreover, a few shared characters with Neanderthals are consistent with the hypothesis that the SH population and Neanderthals are sister groups. These shared characters are a broad lateral malleolar facet, a trochlear height intermediate between modern humans and Late Pleistocene H. sapiens, and a short middle calcaneal facet. It has been possible to propose sex assignment for the SH tali based on their size. Stature estimates based on these fossils give a mean stature of 174.4 cm for males and 161.9 cm for females, similar to that obtained based on the long bones from this same site.     

Squatting facet: a case study Dilkaya and Van-Kalesi populations in eastern Turkey

Anomalies of the skeleton provide information on living conditions, cultural structure and health problems in ancient societies. Squatting facet is a kind of anomaly that forms on the surfaces where the tibia and talus articulate is the squatting facet states the daily activities and living style of the society. The aim of this study is to learn the daily activities of the medieval societies in the Van region through studying of squatting facets. In this study, adult skeletons from Dilkaya and Van Kalesi-Eski Van Sehri societies dating to the Medieval Age were investigated (65 tibia and 82 tali from Dilkaya, 61 tibia and 52 tali from Van Kalesi-Eski Van Sehri). The lateral squatting facet had high ratios in both societies. The tibia lateral squatting facet found on females and males of Dilkaya was 97.2% and 96.9%, respectively, and on females and males of Van kalesi Eski Van Sehri was 87.5% and 89.2%, respectively. The talus lateral squatting facet found on females and males of Dilkaya was 72.1% and 51.3%, respectively, and on females and males of Van kalesi Eski Van Sehri was 91.2% and 83.7%, respectively. The results provide an opportunity to study the relationship between past and modern population, and also describe the daily activity of life and cultural structure.     

Friction ridges in cockroach climbing pads: anisotropy of shear stress measured on transparent,microstructured substrates

The contact of adhesive structures to rough surfaces has been difficult to investigate as rough surfaces are usually irregular and opaque. Here we use transparent, microstructured surfaces to investigate the performance of tarsal euplantulae in cockroaches (Nauphoeta cinerea). These pads are mainly used for generating pushing forces away from the body. Despite this biological function, shear stress (force per unit area) measurements in immobilized pads showed no significant difference between pushing and pulling on smooth surfaces and on 1-μm high microstructured substrates, where pads made full contact. In contrast, on 4-μm high microstructured substrates, where pads made contact only to the top of the microstructures, shear stress was maximal during a push. This specific direction dependence is explained by the interlocking of the microstructures with nanometre-sized “friction ridges” on the euplantulae. Scanning electron microscopy and atomic force microscopy revealed that these ridges are anisotropic, with steep slopes facing distally and shallow slopes proximally. The absence of a significant direction dependence on smooth and 1-μm high microstructured surfaces suggests the effect of interlocking is masked by the stronger influence of adhesion on friction, which acts equally in both directions. Our findings show that cockroach euplantulae generate friction using both interlocking and adhesion.     

Articular contact at the tibiotalar joint in passive flexion

The knowledge of the contact areas at the tibiotalar articulating surfaces during passive flexion is fundamental for the understanding of ankle joint mobility. Traditional contact area reports are limited by the invasive measuring techniques used and by the complicated loading conditions applied. In the present study, passive flexion tests were performed on three anatomical preparations from lower leg amputation. Roentgen Stereophotogrammetric Analysis was used to accurately reconstruct the position of the tibia and the talus at a number of unconstrained flexion positions. A large number of points was collected on the surface of the tibial mortise and on the trochlea tali by a 3-D digitiser. Articular surfaces were modelled by thin plate splines approximating these points. Relative positions of these surfaces in all the flexion positions were obtained from corresponding bone position data. A distance threshold was chosen to define contact areas. A consistent pattern of contact was found on the articulating surfaces. The area moved anteriorly on both articular surfaces with dorsiflexion. The average position of the contact area centroid along the tibial mortise at maximum plantarflexion and at maximum dorsiflexion was respectively 58% posterior and 40% anterior of the entire antero-posterior length. For increasing dorsiflexion, the contact area moved from medial to lateral in all the specimens.     

The effect of dexamethasone on the functioning of C3 receptor sites on the surfaces of human fibroblasts

The presence of C₃ receptor sites on the cell surfaces of WI-38 fibroblasts was reported in a previous paper. Here the effect of dexamethasone sodium sulfate of C₃ receptor site function was studied. The incubation of WI-38 fibroblasts with dexamethasone sodium sulfate produces the biphasic mode of action, i.e., the growth-stimulating phase with low doses (90–230 μg/ml) and the growth-inhibiting phase with high doses (450–900 μg/ml). The function of C₃ receptor sites on WI-38 fibroblasts seems to be very stable and cannot be suppressed by the pretreatment of WI-38 fibroblasts with dexamethasone in high concentrations, where the cell growth is inhibited.     

A new one-DOF fully parallel mechanism for modelling passive motion at the human tibiotalar joint

Knowledge on how ligaments and articular surfaces guide passive motion at the human ankle joint complex is fundamental for the design of relevant surgical treatments. The paper presents a possible improvement of this knowledge by a new kinematic model of the tibiotalar articulation. Passive motion, i.e. in virtually unloaded conditions, was captured in vitro in four lower leg specimens by means of a surgical navigation system with cluster of active markers attached to the tibia and talus. The anatomical geometry of the passive structures, i.e. articular surfaces and attachment areas of the ligaments, were taken by digitisation with a pointer. An equivalent spatial mechanism for the passive motion simulation was defined by three sphere-to-sphere contact points and two rigid links. These contact points were identified at the lateral talo-fibular articulation and at the medial and lateral aspects of the articulation between tibial mortise and trochlea tali. The two rigid links were identified by the isometric fibres at the calcaneofibular and tibiocalcaneal ligaments. An optimisation algorithm was developed for the identification of the final geometrical parameters resulting from an iterative refining process, which targets best matching between model predictions and corresponding experimental measurements of the spatial motion. The specimen-specific equivalent spatial mechanisms replicated the original passive motion very well, with mean discrepancies in position smaller than 2.5 mm and in rotation smaller than 1°. The study demonstrates that the articular surfaces and the ligaments, acting together as a mechanism, control the passive kinematics of the ankle joint.     

Preparation,Optimization, and Characterization of SERS Sensor Substrates Based on Two-Dimensional Structures of Gold Colloid

Generally, the immobilization of two-dimensional nanoparticles in immersion procedures is time-consuming (over 24 h). In this paper, we report a very effective and simple method to fabricate two-dimensional gold nanoparticle patterns over large areas with high regularity for surface-enhanced Raman scattering (SERS). We achieved a highly sensitive SERS colloid surface by optimizing temperature and immersion time. The surfaces were characterized by X-ray photoelectron spectroscopy, UV–Vis, atomic force microscopy, and scanning electron microscopy. The SERS activity of surfaces was compared by using two techniques: “dip” and “dip and dry” in an aqueous solution of 10⁻⁶ M crystal violet. The influence of the morphology of the surface was investigated with both the dip and dip and dry techniques.     

The role of colony morphology and substratum inclination in the success of Millepora alcicornis on shallow coral reefs

 Millepora species are conspicuous members of shallow coral reefs where they occupy a variety of substrata and produce morphologically complex skeletons. This study focuses on the roles of growth on vertical and horizontal surfaces and the production of encrusting bases and branches (a “sheet-tree” morphology) for the success of the Millepora alcicornis on coral reefs. The effects of inclination were investigated by comparing the size and growth rates of M. alcicornis on vertical and horizontal surfaces at 3–5 m depth, in St. John, US Virgin Islands. The consequences of morphological complexity were investigated by comparing polyp density, chlorophyll content and biomass between encrusting bases and branches; the role of branches in asexual reproduction was also quantified. Colonies on vertical surfaces had larger encrusting bases, longer perimeters and lower densities of branches compared to those on horizontal surfaces. Growth rates also varied significantly between surfaces, largely because colonies on horizontal surfaces shrank in area while those on vertical surfaces increased in area, albeit slowly. Branches were not specialized in comparison to encrusting bases in terms of the density of dactylozooids and gastrozooids, chlorophyll content and biomass, but they were effective asexual propagules. During one storm, 79% of the branches were removed from colonies of M. alcicornis, and 4% attached to the substratum to produce new colonies at a density of ≈0.5 colonies.m^-2. Anecdotal observations suggest that such storms rarely damaged encrusting bases on vertical surfaces, but often destroyed those on horizontal surfaces. Thus, the encrusting bases on vertical surfaces are likely to be large because of greater age rather than faster growth, while those on horizontal surfaces are likely to be small because they are relatively young and short lived. These findings suggest that the success of M. alcicornis is a result, in part, of the beneficial consequences of their “sheet-tree” morphology, that supports: (a) slow growth and resistance to wave damage of encrusting bases on vertical surfaces, and (b) the use of branches as asexual propagules. Accepted: 24 November 1998     

The geometry of the human trochlea tali

The geometrical shape of the trochlea tali is responsible for two completely different courses of motion in the ankle joint setting out from the neutral position: dorsiflexion and plantar flexion. Dorsiflexion: The tibia leads the talus, whereas the fibula is pushed laterally by the screw-shaped lateral articular facet of the talus. The malleoli tightly embrace the trochlea tali, whilst an obvious cleft appears dorsally and medially between the superior articular surface of the talus and the tibial roof. Plantar flexion: The fibula leads the talus which withdraws from the medial malleolus by stretching the anterior talofibular ligament. At the same time the superior articular face of the talus closely contacts the tibial roof.     

Three-dimensional orientations of talar articular surfaces in humans and great apes

The morphology of the talus prescribes relative positions and movements of the calcaneus and navicular with respect to the tibia, hence determining the overall geometry, mobility and function of the foot that mechanically interacts with environments. Clarifying the variations of the articular surface orientations of the talus in humans and extant great apes is therefore of importance in understanding the evolution of bipedal locomotion in the human lineage. The aim of this study is to clarify the three-dimensional orientations of three articular surfaces of the talus (superior, posterior calcaneal and navicular articular surfaces) by means of the newly proposed surface approximation method. Thirty-two tali in humans, chimpanzees, gorillas and orangutans were scanned using a three-dimensional noncontact digitizer, and the articular surfaces were then approximated using a paraboloid or a plane to calculate the orientations of the surfaces with respect to the body of the talus. The results quantitatively demonstrated that the superior articular surfaces in humans were relatively more parallel with the horizontal plane of the talar body, while those in apes were more medially oriented. Furthermore, the cylindrical axis defined by the shape of the posterior calcaneal articular surface was directed less anteroposteriorly in humans than in apes, in contrast to the fact that the subtalar axis is more anteroposteriorly oriented in humans. It was also demonstrated that the navicular articular surface in humans was more plantarly oriented and axially twisted. These specialized features of the human talus seem to be functionally linked to obligate bipedal locomotion. The talar morphological differences among the great apes were prominent in the mediolateral and rotational orientations of the navicular articular surfaces, possibly reflecting the degree of arboreality among the great apes.     

Clonal propagation by the azooxanthellate octocoral Dendronephthya hemprichi

 The azooxanthellate octocoral Dendronephthya hemprichi (Octocorallia, Alcyonacea) is the most abundant benthic organism inhabiting the under-water surfaces of oil jetties at Eilat (Red Sea); however, it is very rare on Eilat’s natural reefs. This soft coral exhibits a newly discovered mode of clonal propagation that results in autotomy of small-sized fragments (2–5 mm in length). They possess specialized root-like processes that enable a rapid attachment onto the substrata. An autotomy event is completed within only 2 days; large colonies can bear hundreds of pre-detached fragments. Temporal fluctuations in the percentage of fragment-bearing colonies indicate that autotomy is stimulated by exogenous factors, probably flow-related events. Recruitment of fragments onto PVC plates placed horizontally adjacent to D. hemprichi colonies, was immediate and remarkably high. Attached fragments were observed 2 days after placement of plates; after 52 days, densities of more than one recruit per cm² were recorded. The negative buoyancy of fragments causes them to land on horizontal surfaces rather than on vertical ones. However, their survivorship on vertical surfaces is much higher. This pattern corresponds with dominance of D. hemprichi on vertical substrata at the oil jetties and on natural vertical reefs of the northern Red Sea. Such a mode of clonal propagation provides an efficient mean for genets of D. hemprichi to exploit food resources within a zooxanthellate-dominated reef community. Accepted: 2 February 1996     

Impact of soil vertical water movement on the energy balance of different land surfaces

The soil heat flux determination method proposed by Gao (Boundary-Layer Meteorol 114:165–178, 2005) is discussed for (1) dry surfaces, (2) bare soil or sparse short-grass lands, and (3) dense-grass surfaces or forest. Our analysis shows that, when neglecting the contribution of soil vertical water movement to soil heat flux, the energy components measured independently will (1) still achieve balance over dry surfaces, and (2) be significantly in imbalance over bare soil or sparse short-grass lands. The mean of bare ground evaporation modeled by SiB2 is 1.58 × 10⁻⁵ m³ s⁻¹ m⁻², and the mean of soil water flux obtained by the method of Gao is 1.22 × 10⁻⁵ m³ s⁻¹ m⁻² for the Naqu site in the summer of 1998. Comparison of the bare ground evaporation with the mean of soil water flux shows a difference, the causes of which are investigated. Physically, the bare ground evaporation is equal to the sum of soil water flux and water content change in the soil surface layer. Because the bare ground evaporation is very limited for the dense-grass surfaces or forest, our analysis implies that the energy imbalance encountered over the dense-grass or forest is not caused by the fact that previous researchers neglected soil water movements in their energy budget analyses.     

A comparative study of the trabecular bony architecture of the talus in humans, non-human primates, and Australopithecus

This study tested the hypothesis that talar trabecular microarchitecture reflects the loading patterns in the primate ankle joint, to determine whether talar trabecular morphology might be useful for inferring locomotor behavior in fossil hominins. Trabecular microarchitecture was quantified in the anteromedial, anterolateral, posteromedial, and posterolateral quadrants of the talar body in humans and non-human primates using micro-computed tomography. Trabecular bone parameters, including bone volume fraction, trabecular number and thickness, and degree of anisotropy differed between primates, but not in a manner entirely consistent with hypotheses derived from locomotor kinematics. Humans have highly organized trabecular struts across the entirety of the talus, consistent with the compressive loads incurred during bipedal walking. Chimpanzees possess a high bone volume fraction, consisting of plate-like trabecular struts. Orangutan tali are filled with a high number of thin, connected trabeculae, particularly in the anterior portion of the talus. Gorillas and baboons have strikingly similar internal architecture of the talus. Intraspecific analyses revealed no regional differences in trabecular architecture unique to bipedal humans. Of the 22 statistically significant regional differences in the human talus, all can also be found in other primates. Trabecular thickness, number, spacing, and connectivity density had the same regional relationship in the talus of humans, chimpanzees, gorillas, and baboons, suggesting a deeply conserved architecture in the primate talus. Australopithecus tali are human-like in most respects, differing most notably in having more oriented struts in the posteromedial quadrant of the body compared with the posterolateral quadrant. Though this result could mean that australopiths loaded their ankles in a unique manner during bipedal gait, the regional variation in degree of anisotropy was similar in humans, chimpanzees, and gorillas. These results collectively suggest that the microarchitecture of the talus does not simply reflect the loading environment, limiting its utility in reconstructing locomotion in fossil primates.     

Morphological and ultrastructural characteristics of symbiotic bacteria colonizing the surface of the helminth Triaenophorus nodulosus and the intestine of pike Esox lucius

The microflora inhabiting the intestinal mucosa of the pike and the tegument surface of the intestinal parasite Triaenophorus nodulosus is investigated. By means of electron microscopy, the ultrastructural features of bacteria and pattern of their interaction with the colonized surfaces are estimated. Specific distribution of microorganisms belonging to different morphotypes and subdivided into subpopulations on the colonized surfaces is found. Predominance of gram-negative bacteria in all studied microbiocenoses and abundance of nanobacteria in the “superficial” subpopulations are observed. The bacteria of “a deep population” associated with the basal parts of microtrichiae and microvilli are described. It is concluded that the helminthes, the fish parasites possess the normal microflora characterized by specific composition, by ultrastructural features of cells, and by patterns of interaction with the helminth surface. The obtained data characterize the mechanisms of symbiotic interaction of prokaryotes and eukaryotes in the system parasite-host-symbiotic microflora.     

Talar morphology of azibiids, strepsirhine-related primates from the Eocene of Algeria: phylogenetic affinities and locomotor adaptation

The HGL-50 locality, situated on the Glib Zegdou outlier in the Gour Lazib of Algeria (Hammada du Dra), is famous for having yielded several dental remains of primates dating from the late Early to the early Middle Eocene. These primates include Algeripithecus minutus, Azibius trerki and a new species of cf. Azibius (not described yet). Algeripithecus was widely acknowledged to be one of the oldest known anthropoids from Africa. However, very recent discoveries strongly suggest that Algeripithecus is closely related to Azibius and that both taxa are phylogenetically remote from the clade Anthropoidea. Algeripithecus and Azibius make up the family Azibiidae and appear as stem strepsirhines. Here we describe and analyse two ankle bones (tali) found in HGL-50. UM/HGL50-466 is a small left talus, which is appropriate in size to belong to A. trerki, while UM/HGL50-467 is a right talus, which is significantly larger and appropriate in size to belong to the new large species of cf. Azibius. Both tali exhibit a suite of features that resemble conditions primarily found in extinct and extant strepsirhine and adapiform primates; conditions that are consistent with the strepsirhine-like dentition characterizing azibiids. Functionally, these two tali indicate that Azibius species were engaged in a form of active arboreal quadrupedalism with some ability to climb and leap. Azibiids were rather small-bodied primates, approximating the size of some modern dwarf lemurs (Cheirogaleidae) and sportive lemurs (Lepilemuridae) from Madagascar. Given their small body-size and their talar morphology, living cheirogaleid lemurs, which are agile arboreal quadrupeds (with climbing, springing and branch running activities), might appear as good analogues for azibiids in terms of locomotor behaviour.     

Normal rat kidney proximal tubule cells in primary and multiple subcultures

Summary Anin vitro model to establish primary and subcultures of rat kidney proximal tubule (RPT) cells is described. After excising the kidneys and separating the cortex, the cortical tissue is digested with the enzyme DNAse-collagenase (Type I) resulting in a high yield of viable RPT Cells. The isolated RPT cells are then seeded onto rat tail collagen-coated surfaces and grown to confluency in a serum-free, hormonally defined medium. The cell yield can be increased by transfering the conditioned medium on Day 1 to more rat tail collagen-coated surfaces. RPT cell attachment and morphology was better on rat tail collagen-coated surfaces than on bovine collagen Type I coated surfaces. The culture medium was a 1∶1 mixture of Ham’s F-12 and Dulbecco’s modified Eagle’s medium supplemented with bovine serum albumin, insulin, transferrin, selenium, hydrocortisone, triiodothyronine, epidermal growth factor, and glutamine. The RPT cells became confluent in 7–10 d, at which point they could be subcultured by trypsinizing and growth in the same medium. In some studies, 10 ng/ml cholera toxin was added to the culture medium. We could passage the RPT cells up to 14 times in the presence of cholera toxin. The cells were investigated for activity of several markers. The cells were histochemically positive for alkaline phosphatase and γ-glutamyl transpeptidase activity and synthesized the intermediate filament pankeratin. The RPT cells displayed apically directed sodium-dependent active glucose transport in culture. Hence, the RPT cells retain structural and functional characteristics of transporting renal epithelia in culture. This rat cell culture model will be a valuable tool for substrate uptake and nephrotoxicity studies.     

Resistance to the Brownian movement of red blood cells on flat horizontal surfaces

The movements of red blood cells (RBC), suspended in plasma, on plastic, glass, rhodium metal plate, siliconized glass, and siliconized rhodium were recorded on cinéfilm and analyzed. Values for the drag coefficient were calculated, using Einstein's theory of Brownian movement, and compared with the theoretical Stokes' hydrodynamic drag. The difference between the computed and Stokes' values gave the frictional coefficient or resistance resulting from the interaction of the cells, with the test surface. Of the three uncoated test surfaces, plastic was found to have the least interaction with the RBC. The frictional coefficient for plastic was found to be 1.75×10⁻⁷ N s m⁻¹ compared with a value of 2.82×10⁻⁷ N s m⁻¹ for rhodium metal, which had the largest interaction. Upon siliconization of the test surfaces, the interaction decreased by 40%. Reduction in the pH of the suspending plasma increased the interaction between the cells and the uncoated test surfaces, but the pH effect of diminished when the surfaces were siliconized.