A metric investigation of the cranial base and vertebrae among extant African homininae: discrimination across posturo-locomotory complexes

Thesis (Ph.D.) University of Alaska Fairbanks, 2017Cranial base angle, vertebral dimensions, vertebral curvature, and locomotive behavior differ among Homo, Pan, and Gorilla; but many distinctions are obfuscated by dimensional and behavioral overlap among the genera and their fossil relatives. To address these issues, cranial and vertebral measurements (suites) were examined among Homo, Gorilla, and Pan as representative hominines for their posture and locomotion or positional-locomotory complexes. An additional analysis considered Australopithecus afarensis (A.L. 288-1 and A.L. 333) for comparative purposes. Using size-adjusted values with applied Bonferroni adjusted alpha levels, significant results for both the Kruskal-Wallis H-test and Mann-Whitney U-tests indicated statistically significant differences among species for cranial base angle (p = 0.000) and vertebral body dimensions with coronal and sagittal facet orientation (p = 0.000 -- 0.003). Detected significance was present for thoracic and lumbar curvature (p = 0.000) and positional-locomotory complex (p = 0.000) among species, albeit only cranial base angle was significant for the Pan-Gorilla comparison. Moreover, post hoc Spearman's rho tests indicated significant results (p = 0.000 -- 0.009) with strong positive and negative correlations throughout the column for each species. However, no pattern among vertebral measurements throughout the vertebral column was detected. Lastly, Multinomial Logistic Regression yielded a correct classification percentage with significant model fit (p = 0.000) of 86.4% for the cranial base, 82.8-97.0% for all subsequent vertebrae, and 80.3% for thoracic and lumbar curvature among species. Positional locomotory complexes were also significant (p = 0.000) and yielded a correct classification percentage of 82.2% among bipeds and the two modes of knuckle-walking practiced by Pan and Gorilla respectively. However, misclassifications between human and nonhuman primates for cranial base angle and calculated vertebral curvature suggest that these variables are not viable for assessing either genera or positional-locomotory complexes. Lastly, both Australopithecus afarensis specimens (A.L. 288-1 and A.L. 333) were incorrectly classified. The A.L. 288-1 specimen identified as Homo and the misclassification of A.L. 333 as Pan suggest either species or vertebra misidentification. Overall, the data indicate that both vertebral corpus dimensions and coronal and sagittal facet orientations differ significantly among hominine taxa and can distinguish species and their respective posturo-locomotory complex. As for the evolutionary implications, human bipedalism is distinct as related to cranial base angle and vertebral measurements; however significant differences between Pan and Gorilla suggest homoplasy among measurements and denote parallelism for the emergence of knuckle-walking

Al-Li Alloys – The Analysis of Material Behaviour during Industrial Hot Forging

Al-Li alloys are a promising class of aerospace materials that combine light weight with high strength, comparable to those of steels. In the case of critical components, it is well known that providing the required reliability is impossible without tailoring the output microstructure of the material. This, in turn, requires a clear understanding of the logic behind microstructure formation depending on the total processing history (especially temperature and strain-rate history). However, uniaxial isothermal laboratory tests provide very limited information about the material behaviour. Real forging processes, especially involving complex geometries, sometimes develop quite complicated temperature-strain-rate paths that vary across the deformed part. A proper analysis of the microstructural transformations taking place in the material under these conditions is therefore very important. In this paper, the correlation between the loading history and microstructural transformations was analysed for AA2099 alloy using the hot forging of a disk-shaped component at selected forging temperatures and strain rates. The obtained results were compared to industrial processing maps based on uniaxial tests

Symplasmic isolation marks cell fate changes during somatic embryogenesis

Cell-to-cell signalling is a major mechanism controlling plant morphogenesis. Transport of signalling molecules through plasmodesmata is one way in which plants promote or restrict intercellular signalling over short distances. Plasmodesmata are membrane-lined pores between cells that regulate the intercellular flow of signalling molecules through changes in their size, creating symplasmic fields of connected cells. Here we examine the role of plasmodesmata and symplasmic communication in the establishment of plant cell totipotency, using somatic embryo induction from Arabidopsis explants as a model system. Cell-to-cell communication was evaluated using fluorescent tracers, supplemented with histological and ultrastructural analysis, and correlated with expression of a WOX2 embryo reporter. We showed that embryogenic cells are isolated symplasmically from non-embryogenic cells regardless of the explant type (immature zygotic embryos or seedlings) and inducer system (2,4-dichlorophenoxyacetic acid or the BABY BOOM (BBM) transcription factor), but that the symplasmic domains in different explants differ with respect to the maximum size of molecule capable of moving through the plasmodesmata. Callose deposition in plasmodesmata preceded WOX2 expression in future sites of somatic embryo development, but later was greatly reduced in WOX2-expressing domains. Callose deposition was also associated with a decrease DR5 auxin response in embryogenic tissue. Treatment of explants with the callose biosynthesis inhibitor 2-deoxy-D-glucose supressed somatic embryo formation in all three systems studied, and also blocked the observed decrease in DR5 expression. Together these data suggest that callose deposition at plasmodesmata is required for symplasmic isolation and establishment of cell totipotency in Arabidopsis

Electron-Shading Characterization in a HDP Contact Etching Process Using a Patterned CHARM Wafer

In this work, a CHARM-2 wafer with high aspect ratio resist patterns has been used to quantitatively I. Introduction To understand the origin of plasma-induced damage, useful plasma parameters such as floating potentials and J-V characteristics can be measured using the non-invasive CHARM method To study this effect, we have designed different resist patterns on a 200 mm CHARM™-2 wafer with an e-beam lithography. This allows to obtain realistic variable aspect ratio as high as 4, contrary to previous studie

Use-Dependent Prosthesis Training Strengthens Contralateral Hemodynamic Brain Responses in a Young Adult With Upper Limb Reduction Deficiency: A Case Report

The purpose of the current case study was to determine the influence of an 8-week home intervention training utilizing a partial hand prosthesis on hemodynamic responses of the brain and gross dexterity in a case participant with congenital unilateral upper-limb reduction deficiency (ULD). The case participant (female, 19 years of age) performed a gross manual dexterity task (Box and Block Test) while measuring brain activity (functional near-infrared spectroscopy; fNIRS) before and after an 8-weeks home intervention training. During baseline, there was a broad cortical activation in the ipsilateral sensorimotor cortex and a non-focalized cortical activation in the contralateral hemisphere, which was non-focalized, while performing a gross manual dexterity task using a prosthesis. After the 8-week home intervention training, however, cortical activation shifted to the contralateral motor cortex while cortical activation was diminished in the ipsilateral hemisphere. Specifically, the oxygenated hemodynamics (HbO) responses increased in the medial aspects of the contralateral primary motor and somatosensory cortices. Thus, these results suggest that an 8-week prosthetic home intervention was able to strengthen contralateral connections in this young adult with congenital partial hand reduction. This was supported by the case participant showing after training an increased flexor tone, increased range of motion of the wrist, and decreased times to complete various gross dexterity tasks. Changes in HbO responses due to the home intervention training follow the mechanisms of use-dependent plasticity and further guide the use of prostheses as a rehabilitation strategy for individuals with ULD

Composite Detectors Based on Single-Crystalline Films and Single Crystals of Garnet Compounds

This manuscript summarizes recent results on the development of composite luminescent materials based on the single-crystalline films and single crystals of simple and mixed garnet compounds obtained by the liquid-phase epitaxy growth method. Such composite materials can be applied as scintillating and thermoluminescent (TL) detectors for radiation monitoring of mixed ionization fluxes, as well as scintillation screens in the microimaging techniques. The film and crystal parts of composite detectors were fabricated from efficient scintillation/TL materials based on Ce3+-, Pr3+-, and Sc3+-doped Lu3Al5O12 garnets, as well as Ce3+-doped Gd3−xAxAl5−yGayO12 mixed garnets, where A = Lu or Tb; x = 0–1; y = 2–3 with significantly different scintillation decay or positions of the main peaks in their TL glow curves. This work also summarizes the results of optical study of films, crystals, and epitaxial structures of these garnet compounds using absorption, cathodoluminescence, and photoluminescence. The scintillation and TL properties of the developed materials under α- and β-particles and γ-quanta excitations were studied as well. The most efficient variants of the composite scintillation and TL detectors for monitoring of composition of mixed beams of ionizing radiation were selected based on the results of this complex study