Linking the proximal tibiofibular joint to hominid locomotion: A morphometric study of extant species

Objectives: We perform a comparative assessment of shape variation of the proximal fibula in extant humans and great apes, intending to investigate the possible link between proximal fibular shape and locomotor patterns.Methods: Our sample includes 94 fibulae of 37 Homo sapiens, 15 Gorilla, 17 Pongo, and 25 Pan. Fibular morphology was investigated through three-dimensional (semi)landmark-based geometric morphometric methods.Results: We found unique features of the human fibular head compared to that of great apes (i.e., oblique articular surface, the presence of the styloid process, specific morphology of muscle attachment sites), supporting the functional role of this bone in relation to human obligate bipedalism. Great apes also showed distinctive traits in their proximal fibula morphology, in agreement with differences in locomotor behavior.Conclusion: The morphology of the proximal fibula in extant humans and great apes is indicative of locomotor behavior, offering the potential for the comparative analysis of fossil hominin remains

A strontium isoscape of Italy for provenance studies

We present a novel database of biological and geological 87Sr/86Sr values (n = 1920) from Italy, using literature data and newly analysed samples, for provenance purposes. We collected both bioavailable and non-bioavailable (i.e. rocks and bulk soils) data to attain a broader view of the Sr isotope variability of the Italian territory. These data were used to build isotope variability maps, namely isoscapes, through Kriging interpolations. We employed two different Kriging models, namely Ordinary Kriging and Universal Kriging, with a geolithological map of Italy categorized in isotope classes as external predictor. Model performances were evaluated through a 10-fold cross validation, yielding accurate 87Sr/86Sr predictions with root mean squared errors (RMSE) ranging between 0.0020 and 0.0024, dependent on the Kriging model and the sample class. Overall, the produced maps highlight a heterogeneous distribution of the 87Sr/86Sr across Italy, with the highest radiogenic values (>0.71) mainly localized in three areas, namely the Alps (Northern Italy), the Tuscany/Latium (Central Italy) and Calabria/Sicily (Southern Italy) magmatic/metamorphic terrains. The rest of the peninsula is characterized by values ranging between 0.707 and 0.710, mostly linked to sedimentary geological units of mixed nature. Finally, we took advantage of the case study of Fratta Polesine, to underscore the importance of choosing appropriate samples when building the local isoscape and of exploring different end-members when interpreting the local Sr isotope variability in mobility and provenance studies. Our user-friendly maps and database are freely accessible through the Geonode platform and will be updated over time to offer a state-of-the-art reference in mobility and provenance studies across the Italian landscape

Isolation of intermediate compounds between hemoglobin and carbon monoxide.

A human hemoglobin solution partially saturated with carbon monoxide was rapidly quenched at -25 degrees C into a hydro-organic buffer containing ferricyanide. Under the experimental conditions of pH, ionic strength, and buffer composition used in this work, it was found that the deoxy hemes were rapidly transformed into their met form, whereas practically no carbon monoxide-bound hemes were oxidized before the separation of the mixture from the oxidizing agent. As a preliminary step to the analysis of the resulting solution, carbonylhemoglobin solutions partially oxidized with ferricyanide were studied by isoelectric focusing at -25 degrees C under identical conditions. The relative position in the gel of all nine possible valence hybrids was established as follows (going from the anodic to the cathodic side of the gel) alpha CO2 beta CO2, (alpha CO beta +)(alpha CO beta CO) (alpha CO beta CO), (alpha CO2 beta +2), (alpha + beta CO), (alpha + beta +)-(alpha CO beta CO), (alpha + beta +)(alpha CO beta +), (alpha +2 beta CO2), (alpha + beta +)(alpha + beta CO), alpha +2 beta +2. When carbonylhemoglobin and methemoglobin were mixed in equal proportion at -25 degrees C and then analyzed by isoelectric focusing at the same temperature, it was found that the contribution of valence hybrids other than alpha CO2 beta CO2 and alpha +2 beta +2 to the total amount of hemoglobin in the gel was no more than 6%. When carbonylhemoglobin and deoxyhemoglobin were mixed in the same proportion and incubated at 20 degrees C so to allow the redistribution of the carbon monoxide molecules between all possible binding sites to occur, a substantially higher amount of valence hybrids, derived from the oxidation of intermediate compounds of hemoglobin with carbon monoxide, was found. The isoelectric focusing separation indicated the presence in the original solution of intermediate species other than carbonylhemoglobin and deoxyhemoglobin at a concentration of about 10% of the total

Secondary dentin formation mechanism: The effect of attrition

Human dentin consists of a primary layer produced during tooth formation in early child-hood and a second layer which first forms upon tooth eruption and continues throughout life, termed secondary dentin (SD). The effect of attrition on SD formation was considered to be confined to the area subjacent to attrition facets. However, due to a lack of three‐dimensional methodologies to demonstrate the structure of the SD, this association could not be determined. Therefore, in the current study, we aimed to explore the thickening pattern of the SD in relation to the amount of occlusal and interproximal attrition. A total of 30 premolars (50–60 years of age) with varying attrition rates were evaluated using micro‐computerized tomography. The results revealed thickening of the SD below the cementoenamel junction (CEJ), mostly in the mesial and distal aspects of the root (p < 0.05). The pattern of thickening under the tooth cervix, rather than in proximity to attrition facets, was consistent regardless of the attrition level. The amount of SD thickening mildly corre-lated with occlusal attrition (r = 0.577, p < 0.05) and not with interproximal attrition. The thickening of the SD below the CEJ coincided with previous finite element models, suggesting that this area is mostly subjected to stress due to occlusal loadings. Therefore, we suggest that the SD formation might serve as a compensatory mechanism aimed to strengthen tooth structure against deflection caused by mechanical loading. Our study suggests that occlusal forces may play a significant role in SD formation

The cranial biomechanics and feeding performance ofHomo floresiensis

Homo floresiensis is a small-bodied hominin from Flores, Indonesia, that exhibits plesiomorphic dentognathic features, including large premolars and a robust mandible, aspects of which have been considered australopith-like. However, relative to australopith species, H. floresiensis exhibits reduced molar size and a cranium with diminutive midfacial dimensions similar to those of later Homo, suggesting a reduction in the frequency of forceful biting behaviours. Our study uses finite-element analysis to examine the feeding biomechanics of the H. floresiensis cranium. We simulate premolar (P3) and molar (M2) biting in a finite-element model (FEM) of the H. floresiensis holotype cranium (LB1) and compare the mechanical results with FEMs of chimpanzees, modern humans and a sample of australopiths (MH1, Sts 5, OH5). With few exceptions, strain magnitudes in LB1 resemble elevated levels observed in modern Homo. Our analysis of LB1 suggests that H. floresiensis could produce bite forces with high mechanical efficiency, but was subject to tensile jaw joint reaction forces during molar biting, which perhaps constrained maximum postcanine bite force production. The inferred feeding biomechanics of H. floresiensis closely resemble modern humans, suggesting that this pattern may have been present in the last common ancestor of Homo sapiens and H. floresiensis

3D enamel thickness in Neandertal and modern human permanent canines

Enamel thickness figures prominently in studies of human evolution, particularly for taxonomy, phylogeny, and paleodietary reconstruction. Attention has focused on molar teeth, through the use of advanced imaging technologies and novel protocols. Despite the important results achieved thus far, further work is needed to investigate all tooth classes. We apply a recent approach developed for anterior teeth to investigate the 3D enamel thickness of Neandertal and modern human (MH) canines. In terms of crown size, the values obtained for both upper and lower unworn/slightly worn canines are significantly greater in Neandertals than in Upper Paleolithic and recent MH. The 3D relative enamel thickness (RET) is significantly lower in Neandertals than in MH. Moreover, differences in 3D RET values between the two groups appear to decrease in worn canines beginning from wear stage 3, suggesting that both the pattern and the stage of wear may have important effects on the 3D RET value. Nevertheless, the 3D average enamel thickness (AET) does not differ between the two groups. In both groups, 3D AET and 3D RET indices are greater in upper canines than in lower canines, and overall the enamel is thicker on the occlusal half of the labial aspect of the crown, particularly in MH. By contrast, the few early modern humans investigated show the highest volumes of enamel while for all other components of 3D enamel, thickness this group holds an intermediate position between Neandertals and recent MH. Overall, our study supports the general findings that Neandertals have relatively thinner enamel than MH (as also observed in molars), indicating that unworn/slightly worn canines can be successfully used to discriminate between the two groups. Further studies, however, are needed to understand whether these differences are functionally related or are the result of pleiotropic or genetic drift effects

A porous fibrous hyperelastic damage model for human periodontal ligament: Application of a microcomputerized tomography finite element model

The periodontal ligament (PDL) is a soft biological tissue that connects the tooth with the trabecular bone of the mandible. It plays a key role in load transmission and is primarily responsible for bone resorption and most common periodontal diseases. Although several numerical studies have analysed the biomechanical response of the PDL, most did not consider its porous fibrous structure, and only a few analysed damage to the PDL. This study presents an innovative numerical formulation of a porous fibrous hyperelastic damage material model for the PDL. The model considers two separate softening phenomena: fibre alignment during loading and fibre rupture. The parameters for the material model characterization were fitted using experimental data from the literature. Furthermore, the experimental tests used for characterization were computationally modelled to verify the material parameters. A finite element model of a portion of a human mandible, obtained by microcomputerized tomography, was developed, and the proposed constitutive model was implemented for the PDL. Our results confirm that damage to the PDL may occur mainly because of overpressure of the interstitial fluid, while large forces must be applied to damage the PDL fibrous network. Moreover, this study clarifies some aspects of the relationship between PDL damage and the bone remodelling process

Principaux motifs de saisie du poulet de chair préparé au niveau d’un abattoir avicole

The objective of the present work was to determine the main rejection lesions associated with poultry carcasses prepared in an industrial slaughterhouse, by microscopic and macroscopic examination of lesions encountered on carcasses and in offals. Ante-mortem examination showed that the main rejection reasons at this step were death or apparent death, general bad body conditions, along with a defective state resulting from removal and transportation of poultry. Post-mortem examination revealed many rejection reasons for the whole carcass, when lesions were generalized (séro-hemorragic infiltrations, cachexy, hvdrohémia, abnormal color, echymoses...), or for parts of carcasses when lesions were limited. In volume, condemnation rate did not exceede 1%. The percentage of carcasses condemned because of poor slaughtring conditions (overscalding...) was very low. This further emphasizes the need to prepare poultry in industrial slaughter houses.The microscopic study, carried out on rejected offals showed a dominance of fibrinous perihepatic lesions (50% of rejected livers), of fibrinous pericarditis (66% of condemned hearts) along with lung congestion and fibrino-suppurative bronchopneumonia (82% of rejected lung). Such microscopic lesions could mainly be related to dominant diseases such as colibacillosis and salmonellosis. Keys works: Poultry, poultry slaughtering, rejection motives, macroscopic lesions, microscopic lesionsLe but du présent travail est l'étude des principaux motifs de saisie de la volaille préparée au niveau d'un abattoir avicole par l'analyse macroscopique et microscopique des lésions rencontrées sur les carcasses et les abats. A l'examen ante-mortem, la volaille a été saisie sur pied pour cause de mort ou de mort apparente, de perturbation de l'état général, et d'anomalies liées à des conditions défectueuses de ramassage et de transport de la volaille. Les résultats obtenus à l'examen post-mortem font apparaître une multitude de motifs de saisie qui intéressent soit la totalité de la carcasse quand les lésions sont généralisées (infiltrationsséro-hémorragiques, cachexie, hydrohémie, couleur anormale, ecchymoses...) soit une partie de la carcasse lorsque ces lésions sont limitées. Le pourcentage des saisies par rapport au tonnage réalisé reste très faible et ne dépasse pas 1%.La quantité de viande saisie pour motifs d’accidents d'abattage et de préparation est très négligeable, ce qui apporte une preuve supplémentaire à la nécessité de préparer le poulet dans un abattoir avicole. L'étude microscopique réalisée sur les abats saisis révèle une dominance des péri- hépatites fibrineuses (soit 50% des foies saisis), des péricardites fibrineuses (66% des cœurs saisis) ainsi que des congestions pulmonaires et des broncho-pneumonies fibrino-suppurées (82% des poumons saisis).Les aspects lésionnels rencontrés pourraient être surtout associés à des entités pathologiques telles que la colibacillose et les salmonelloses. Mots clés: Volaille, abattoir, motifs de saisie, lésions, étude macroscopique et microscopiqu

Fast offline data reduction of laser ablation MC-ICP-MS Sr isotope measurements: Via an interactive Excel-based spreadsheet 'SrDR'

Strontium isotopes are applied to a wide range of scientific fields and to different types of materials, providing valuable information foremost about provenance and age, but also on diagenetic processes and mixing relationships between different Sr reservoirs. The development of in situ analytical techniques, such as laser ablation ICP-MS, has improved our understanding of Sr isotope variability in several fields of application, because of the possibility to discriminate small-scale changes and their spatial distribution. However, large outputs of Sr isotope data are produced by laser ablation MC-ICP-MS systems, which necessitate multiple offline steps to correct and assess the data. This requires the availability of simple and user-friendly tools, easily manageable by non-specialists too. With this in mind, we developed SrDR, an Excel-based interactive data reduction spreadsheet ('SrDR', Sr-Data-Reduction) for the processing of Sr isotopes measured by LA-MC-ICP-MS. The SrDR spreadsheet is easily customizable (a) to meet user-specific analytical protocols, (b) for different instruments (i.e. Nu plasma vs. Neptune), and (c) for diverse target materials (e.g. rare earth element enriched or depleted samples). We also include several examples relevant to low and high temperature geochemistry fields-a fossil tooth, a modern seashell, a speleothem sample and plagioclase crystals-to show how different sample materials are corrected for different interfering masses