Thermo-micro-mechanical simulation of bulk metal forming processes

The newly proposed microstructural constitutive model for polycrystal viscoplasticity in cold and warm regimes (Motaman and Prahl, 2019), is implemented as a microstructural solver via user-defined material subroutine in a finite element (FE) software. Addition of the microstructural solver to the default thermal and mechanical solvers of a standard FE package enabled coupled thermo-micro-mechanical or thermal-microstructural-mechanical (TMM) simulation of cold and warm bulk metal forming processes. The microstructural solver, which incrementally calculates the evolution of microstructural state variables (MSVs) and their correlation to the thermal and mechanical variables, is implemented based on the constitutive theory of isotropic hypoelasto-viscoplastic (HEVP) finite (large) strain/deformation. The numerical integration and algorithmic procedure of the FE implementation are explained in detail. Then, the viability of this approach is shown for (TMM-) FE simulation of an industrial multistep warm forging

Fluctuations in a diffusive medium with gain

We present a stochastic model for amplifying, diffusive media like, for instance, random lasers. Starting from a simple random-walk model, we derive a stochastic partial differential equation for the energy field with contains a multiplicative random-advection term yielding intermittency and power-law distributions of the field itself. Dimensional analysis indicate that such features are more likely to be observed for small enough samples and in lower spatial dimensions

Development of a Sandwich ELISA to Measure Exposure to Occupational Cow Hair Allergens

Background: Cow hair and dander are important inducers of occupational allergies in cattle-exposed farmers. To estimate allergen exposure in farming environments, a sensitive enzyme immunoassay was developed to measure cow hair allergens. Methods: A sandwich ELISA was developed using polyclonal rabbit antibodies against a mixture of hair extracts from different cattle breeds. To assess the specificity of the assay, extracts from other mammalian epithelia, mites, molds and grains were tested. To validate the new assay, cow hair allergens were measured in passive airborne dust samples from the stables and homes of farmers. Dust was collected with electrostatic dust fall collectors (EDCs). Results: The sandwich ELISA was found to be very sensitive (detection limit: 0.1 ng/ml) and highly reproducible, demonstrating intra-and interassay coefficients of variation of 4 and 10%, respectively. The assay showed no reactivity with mites, molds and grains, but some cross-reactivity with other mammalian epithelia, with the strongest reaction with goat. Using EDCs for dust sampling, high concentrations of bovine allergens were measured in cow stables (4,760-559,400 mu g/m(2)). In addition, bovine allergens were detected in all areas of cattle farmer dwellings. A large variation was found between individual samples (0.3-900 mu g/m(2)) and significantly higher values were discovered in changing rooms. Conclusion: The ELISA developed for the detection of cow hair proteins is a useful tool for allergen quantification in occupational and home environments. Based on its low detection limit, this test is sensitive enough to detect allergens in passive airborne dust. Copyright (C) 2011 S. Karger AG, Base

Self-concept and facial appearance of individuals with an intellectual disability:A scoping review

This paper looks at how self-concept is related to facial appearance. Very little information can be found on how persons with intellectual disabilities think and feel about their own facial appearance. In this review 19 articles on subject of self-concept in people with intellectual disabilities were included. Results show that self-concept of individuals with intellectual disabilities is affected by the relationships they have (positively and negatively). The perceptions of caregivers, peers and their awareness of stigma effects self-concept. How facial appearance affects the self-concept of persons with intellectual disabilities remains unclear and should be a focus of research in future. Abstract: Background The mental health and well-being of individuals can be positively affected by improving facial appearance through orthodontic treatment. However, research is limited on the relationship between facial appearance and self-concept of individuals with intellectual disabilities. Materials and methods This scoping review includes 19 articles and is aimed to examine the self-concept of individuals with intellectual disabilities and determine how the self-concept might be impacted by facial appearance. Furthermore, this review is exploratory in the way that an attempt was made to extract constructs that contribute to the self-concept of persons with intellectual disabilities. Results Unfortunately, no articles were found on how individuals with intellectual disabilities think about their own facial appearance. However, the articles on self-concept in persons with intellectual disabilities do mention some interesting facts: social comparisons lead to social stigma that can contribute negatively to the self-concept of individuals with intellectual disabilities. Also, the ability to communicate and express oneself can contribute to one's self-esteem. Furthermore, parents/caregivers often influence the concept of oneself. Moreover, an individual's relationship with their social environment defines their self-concept. Conclusion It is currently unknown how individuals with intellectual disabilities view their own facial appearance and whether their self-concept is influenced by their appearance. Questionnaires which address attitudes on facial appearance could provide a deeper understanding of the self-concept of individuals with intellectual disabilities and possibly make way for orthodontic treatment. However, caution is needed concerning changing the physical appearance of persons with intellectual disabilities. One should also battle stigma by encouraging the social inclusion of persons with intellectual disability

The Search for Ferroelectric domain structures in carbohydrate glasses using atomic force microscopy

D-glucose was studied as a possible candidate for ferroelectric domain imaging using an Atomic Force Microscope (AFM). The large dipole moment of carbohydrates is such that they may show localized ferroelectric domain formation in liquid phase. Samples were heated at their melting point on glass slides and then left to cool to room temperature in a desiccator. Differential Thermal Analysis (DTA) was used to test the effectiveness of this method, and it was found that the oven preparation created samples with 41% crystallinity, where both a glass transition and sharp melting peak were observed. DTA was again used to find a way to create a better amorphous sample. An assessment of the effect of cooling rate on glass formation was conducted using a Differential Scanning Calorimeter (DSC). Surface images of a ferroelectric ceramic and the surface of an amorphous glucose sample were taken using AFM Constant Force Topography

Multispectral imaging of organ viability during uterine transplantation surgery in rabbits and sheep

Uterine transplantation surgery (UTx) has been proposed as a treatment for permanent absolute uterine factor infertility (AUFI) in the case of the congenital absence or surgical removal of the uterus. Successful surgical attachment of the organ and its associated vasculature is essential for the organ’s reperfusion and long-term viability. Spectral imaging techniques have demonstrated the potential for the measurement of hemodynamics in medical applications. These involve the measurement of reflectance spectra by acquiring images of the tissue in different wavebands. Measures of tissue constituents at each pixel can then be extracted from these spectra through modeling of the light–tissue interaction. A multispectral imaging (MSI) laparoscope was used in sheep and rabbit UTx models to study short- and long-term changes in oxygen saturation following surgery. The whole organ was imaged in the donor and recipient animals in parallel with point measurements from a pulse oximeter. Imaging results confirmed the re-establishment of adequate perfusion in the transplanted organ after surgery. Cornual oxygenation trends measured with MSI are consistent with pulse oximeter readings, showing decreased StO2 immediately after anastomosis of the blood vessels. Long-term results show recovery of StO2 to preoperative levels

Integrin-mediated traction force enhances paxillin molecular associations and adhesion dynamics that increase the invasiveness of tumor cells into a three-dimensional extracellular matrix.

Metastasis requires tumor cells to navigate through a stiff stroma and squeeze through confined microenvironments. Whether tumors exploit unique biophysical properties to metastasize remains unclear. Data show that invading mammary tumor cells, when cultured in a stiffened three-dimensional extracellular matrix that recapitulates the primary tumor stroma, adopt a basal-like phenotype. Metastatic tumor cells and basal-like tumor cells exert higher integrin-mediated traction forces at the bulk and molecular levels, consistent with a motor-clutch model in which motors and clutches are both increased. Basal-like nonmalignant mammary epithelial cells also display an altered integrin adhesion molecular organization at the nanoscale and recruit a suite of paxillin-associated proteins implicated in invasion and metastasis. Phosphorylation of paxillin by Src family kinases, which regulates adhesion turnover, is similarly enhanced in the metastatic and basal-like tumor cells, fostered by a stiff matrix, and critical for tumor cell invasion in our assays. Bioinformatics reveals an unappreciated relationship between Src kinases, paxillin, and survival of breast cancer patients. Thus adoption of the basal-like adhesion phenotype may favor the recruitment of molecules that facilitate tumor metastasis to integrin-based adhesions. Analysis of the physical properties of tumor cells and integrin adhesion composition in biopsies may be predictive of patient outcome