New specimens of the basal ornithischian dinosaur Lesothosaurus diagnosticus Galton, 1978 from the Early Jurassic of South Africa

We describe new specimens of the basal ornithischian dinosaur Lesothosaurus diagnosticus Galton, 1978 collected from a bonebed in the Fouriesburg district of the Free State, South Africa. The material was collected from the upper Elliot Formation (Early Jurassic) and represents the remains of at least three individuals. These individuals are larger in body size than those already known in museum collections and offer additional information on cranial ontogeny in the taxon. Moreover, they are similar in size to the sympatric taxon Stormbergia dangershoeki. The discovery of three individuals at this locality might imply group-living behaviour in this early ornithischian.Palaeontologia africana 2016. ©2016 Paul M. Barrett, Richard J. Butler, Adam M. Yates, Matthew G. Baron&Jonah N. Choiniere. This is an open-access article published under the Creative Commons Attribution 4.0 Unported License (CC BY4.0). To view a copy of the license, please visit http://creativecommons.org/licenses/by/4.0/. This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This item is permanently archived at: http://wiredspace.wits.ac.za/handle/10539/19886. The attached file is the published version of the article

Biomechanical Characterisation of the Human Auricular Cartilages; Implications for Tissue Engineering

Currently, autologous cartilage provides the gold standard for auricular reconstruction. However, synthetic biomaterials offer a number of advantages for ear reconstruction including decreased donor site morbidity and earlier surgery. Critical to implant success is the material's mechanical properties as this affects biocompatibility and extrusion. The aim of this study was to determine the biomechanical properties of human auricular cartilage. Auricular cartilage from fifteen cadavers was indented with displacement of 1 mm/s and load of 300 g to obtain a Young's modulus in compression. Histological analysis of the auricle was conducted according to glycoprotein, collagen, and elastin content. The compression modulus was calculated for each part of the auricle with the tragus at 1.67 ± 0.61 MPa, antitragus 1.79 ± 0.56 MPa, concha 2.08 ± 0.70 MPa, antihelix 1.71 ± 0.63 MPa, and helix 1.41 ± 0.67 MPa. The concha showed to have a significantly greater Young's Elastic Modulus than the helix in compression (p < 0.05). The histological analysis demonstrated that the auricle has a homogenous structure in terms of chondrocyte morphology, extracellular matrix and elastin content. This study provides new information on the compressive mechanical properties and histological analysis of the human auricular cartilage, allowing surgeons to have a better understanding of suitable replacements. This study has provided a reference, by which cartilage replacements should be developed for auricular reconstruction

Biomechanical characterisation of the human nasal cartilages; implications for tissue engineering

Nasal reconstruction is currently performed using autologous grafts provides but is limited by donor site morbidity, tissue availability and potentially graft failure. Additionally, current alternative alloplastic materials are limited by their high extrusion and infection rates. Matching mechanical properties of synthetic materials to the native tissue they are replacing has shown to be important in the biocompatibility of implants. To date the mechanical properties of the human nasal cartilages has not been studied in depth to be able to create tissue-engineered replacements with similar mechanical properties to native tissue. The young's modulus was characterized in compression on fresh-frozen human cadaveric septal, alar, and lateral cartilage. Due to the functional differences experienced by the various aspects of the septal cartilage, 16 regions were evaluated with an average elastic modulus of 2.72 ± 0.63 MPa. Furthermore, the posterior septum was found to be significantly stiffer than the anterior septum (p < 0.01). The medial and lateral alar cartilages were tested at four points with an elastic modulus ranging from 2.09 ± 0.81 MPa, with no significant difference between the cartilages (p < 0.78). The lateral cartilage was tested once in all cadavers with an average elastic modulus of 0.98 ± 0.29 MPa. In conclusion, this study provides new information on the compressive mechanical properties of the human nasal cartilage, allowing surgeons to have a better understanding of the difference between the mechanical properties of the individual nasal cartilages. This study has provided a reference, by which tissue-engineered should be developed for effective cartilage replacements for nasal reconstruction

Pesticide Exposure Alters Follicle-Stimulating Hormone Levels in Mexican Agricultural Workers

Organophosphorous pesticides (OPs) are suspected of altering reproductive function by reducing brain acetylcholinesterase activity and monoamine levels, thus impairing hypothalamic and/or pituitary endocrine functions and gonadal processes. Our objective was to evaluate in a longitudinal study the association between OP exposure and serum levels of pituitary and sex hormones. Urinary OP metabolite levels were measured by gas–liquid chromatography, and serum pituitary and sex hormone levels by enzymatic immunoassay and radioimmunoassay in 64 men. A total of 147 urine and blood samples were analyzed for each parameter. More than 80% of the participants had at least one OP metabolite in their urine samples. The most frequent metabolite found was diethylthiophosphate (DETP; 55%), followed by diethylphosphate (DEP; 46%), dimethylthiophosphate (DMTP; 32%), and dimethyldithiophosphate (DMDTP; 31%). However, the metabolites detected at higher concentrations were DMTP, DEP, DMDTP, and dimethylphosphate. There was a high proportion of individuals with follicle-stimulating hormone (FSH) concentrations outside the range of normality (48%). The average FSH serum levels were higher during the heavy pesticide spraying season. However, a multivariate analysis of data collected in all periods showed that serum FSH levels were negatively associated with urinary concentrations of both DMTP and DMDTP, whereas luteinizing hormone (LH) was negatively associated with DMTP. We observed no significant associations between estradiol or testosterone serum levels with OP metabolites. The hormonal disruption in agricultural workers presented here, together with results from experimental animal studies, suggests that OP exposure disrupts the hypothalamic–pituitary endocrine function and also indicates that FSH and LH are the hormones most affected

The organic seed regulations framework in Europe – current status and recommendations for future development

Organic agriculture regulations, in particular European regulation EC 889/2008, prescribe the use of organically produced seed. For many cultivated plants, however, organic seed is often not available. This is mainly because investment in organic plant breeding and seed production has been low in the past. To bridge the gap between organic seed supply and demand, national and European regulations define certain circumstances under which organic producers are permitted to use non-organically produced seed. While the organic sector currently depends on these concessions, they also threaten to impede a further increase in the demand for organic seed, thereby potentially restraining present and future investment in organic seed production and plant breeding. We review the current status of the organic seed regulations framework by analysing key issues such as the role of the national derogation regimes, the role of expert groups, databases and seed prices. Key points are that (a) the situation of the organic seed sector has improved over the last few years; however, (b) reporting on organic seed to the EU by different countries needs to be harmonised; (c) the success of the organic seed sector depends critically on the implementation and improvement of national expert groups; and (d) to protect genetic diversity, the use of local varieties and landraces should not be impeded by organic seed regulations

GRB 180620A: Evidence for Late-time Energy Injection

The early optical emission of gamma-ray bursts (GRBs) gives an opportunity to understand the central engine and first stages of these events. About 30% of GRBs present flares whose origin is still a subject of discussion. We present optical photometry of GRB 180620A with the COATLI telescope and RATIR instrument. COATLI started to observe from the end of prompt emission at T + 39.3 s and RATIR from T + 121.4 s. We supplement the optical data with the X-ray light curve from Swift/XRT. We observe an optical flare from T + 110 s to T + 550 s, with a temporal index decay α O,decay = 1.32 ± 0.01, and Δt/t = 1.63, which we interpret as the signature of a reverse shock component. After the initial normal decay the light curves show a long plateau from T + 500 s to T + 7800 s in both X-rays and the optical before decaying again after an achromatic jet break at T + 7800 s. Fluctuations are seen during the plateau phase in the optical. Adding to the complexity of GRB afterglows, the plateau phase (typically associated with the coasting phase of the jet) is seen in this object after the "normal" decay phase (associated with the deceleration phase of the jet), and the jet break phase occurs directly after the plateau. We suggest that this sequence of events can be explained by a rapid deceleration of the jet with t d ≲ 40 s due to the high density of the environment (≈100 cm-3) followed by reactivation of the central engine, which causes the flare and powers the plateau phase