Shape distortions in fabric reinforced composite products due to processing induced fibre reorientation

Woven fabric reinforced composite materials are typically applied in plate or shell structures, such as ribs, stiffeners and skins. Products of these types can be produced with several production processes. A few examples are diaphragm forming, matched metal die forming and rubber press forming. Shape distortions can occur during manufacturing of composite products. During the development stage of the products these distortions often exceed the high dimensional accuracy required in, for example, the aeronautical and car industry. Costly trial and error methods are generally applied to meet the dimensional accuracy. Modelling the shape distortions on beforehand can aid to reduce the development costs of these products

Warpage of rubber pressed composites

The rubber pressing process is applied for the rapid production of thermoplastic composite products. However, rubber pressed products show geometrical distortions, such as warpage, due to process-induced residual stresses. It is believed that these stresses build up as a result of the large thermal gradients that are present during consolidation. An experimental study is performed to measure the curvature after rubber pressing of initially flat woven fabric glass/PPS composite panels. A material model is proposed that incorporates the solidification of the composite in order to predict the residual stresses and the warpage due to inhomogenous cooling. The model is employed in Finite Element simulations of the rubber pressing process. The simulations are compared to the experimentally obtained curvatures. It shows that inhomogeneous cooling has a minor effect on the warpage in this case, and that another mechanism is present

Production and characterization of miro- and nano-features in biomedical alumina and zirconia ceramics using a tape casting route

A process of micromolding, delivering micro- and nanopatterned ceramic surfaces for biomaterial applications is described in this work. To create the desired structures, tape casting of ceramic slurries on microfabricated silicon mold was used. Several tape casting slurry compositions were tested to evaluate the feasibility of transferring micro- and nano-features from silicon molds. Used ceramics were alumina (α-Al2O3) and yttria stabilized zirconia. Three types of polymeric binders for the green tape (PVB, PES, and PVP) were investigated using three different solvents (ethanol, n-methyl-pyrrolidone, water). Well-defined features in shapes of wells with diameters down to 2.4 μm and a depth of 10 μm and pillars with diameters down to 1.7 μm and a height of 3 μm were obtained. Morphology, grain size and porosity of the sintered bodies were characterized. Finally fibroblast cells were cultured on the surfaces in order to observe their morphology under influence of the microstructured surfaces

Starvation Induces Phase-Specific Changes in the Proteome of Mouse Small Intestine

Food deprivation results in metabolic, structural, and functional changes in the small intestine that influences gut mucosal integrity, epithelial cell proliferation, mucin synthesis, and other processes. The underlying mechanisms are still unclear, which lead to the study of molecular effects of short-term and long-term starvation in the intestine of mice. A comparative proteomics approach, combining two-dimensional gel electrophoresis with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, was used to identify intestinal proteins whose expression is changed under different starvation conditions (0, 12, 24, and 72 h). In total, the expression levels of 80 protein spots changed significantly between the different groups. The results demonstrate that after 12 h of starvation, mainly proteins involved in glycolysis and energy metabolism show decreased expression levels. Starvation for 24 h results in a down-regulation of proteins involved in protein synthesis and amino acid metabolism. Simultaneously, proteins with a protective role, e.g., reg I and II, glutathione peroxidase 3, and carbonic anhydrase 3, are clearly up-regulated. The last starvation phase (72 h) is characterized by increased ezrin expression, which may enhance villus morphogenesis critical for survival. Together, these results provide novel insights in the intestinal starvation response and may contribute to improved nutritional support during conditions characterized by malnutrition

Blood-based kinase activity profiling: A potential predictor of response to immune checkpoint inhibition in metastatic cancer

Background Many cancer patients do not obtain clinical benefit from immune checkpoint inhibition. Checkpoint blockade targets T cells, suggesting that tyrosine kinase activity profiling of baseline peripheral blood mononuclear cells may predict clinical outcome. Methods Here a total of 160 patients with advanced melanoma or non-small-cell lung cancer (NSCLC), treated with anti-cytotoxic T-lymphocyte-associated protein 4 (anti-CTLA-4) or anti-programmed cell death 1 (anti-PD-1), were divided into five discovery and cross-validation cohorts. The kinase activity profile was generated by analyzing phosphorylation of peripheral blood mononuclear cell lysates in a microarray comprising of 144 peptides derived from sites that are substrates for protein tyrosine kinases. Binary grouping into patients with or without clinical benefit was based on Response Evaluation Criteria in Solid Tumors V.1.1. Predictive models were trained using partial least square discriminant analysis (PLS-DA), performance of the models was evaluated by estimating the correct classification rate (CCR) using cross-validation. Results The kinase phosphorylation signatures segregated responders from non-responders by differences in canonical pathways governing T-cell migration, infiltration and co-stimulation. PLS-DA resulted in a CCR of 100% and 93% in the anti-CTLA-4 and anti-PD1 melanoma discovery cohorts, respectively. Cross-validation cohorts to estimate the accuracy of the predictive models showed CCRs of 83% for anti-CTLA-

Nanotopography on implant biomaterials

No abstract

Initial cellular response to laser surface engineered biomaterials

Introducing micro- and nanoscale features on biomaterials in an engineered, controlled manner has been shown to positively affect medical implant integration into the human body. A key factor in this process is the initial cellular response toward the implant. Different techniques such as chemical treatment, plasma spraying, lithography, and coatings, among others, have been applied during the last decades to improve the implant integration. One of the methods that started to be recently exploited is laser surface engineering (LSE). LSE offers a wide range of new surface engineering methods, such as laser surface melting (LSM), laser engineered net shaping (LENS), and selective laser melting/sintering (SLM/S) that can generate complex micro- and nanoscale features with high resolution. This review provides an overview of the initial cellular response to medical implants and the different techniques used to modify the surface of different biomaterials. An emphasis is given to laser techniques that were recently developed for surface texturing, describing in vitro, pre-clinical, and clinical trials performed thus far

Comparative proteomic analysis of cell lines and scrapings of the human intestinal epithelium

<p>Abstract</p> <p>Background</p> <p><it>In vitro </it>models are indispensable study objects in the fields of cell and molecular biology, with advantages such as accessibility, homogeneity of the cell population, reproducibility, and growth rate. The Caco-2 cell line, originating from a colon carcinoma, is a widely used <it>in vitro </it>model for small intestinal epithelium. Cancer cells have an altered metabolism, making it difficult to infer their representativity for the tissue from which they are derived. This study was designed to compare the protein expression pattern of Caco-2 cells with the patterns of intestinal epithelial cells from human small and large intestine. HT-29 intestinal cells, Hep G2 liver cells and TE 671 muscle cells were included too, the latter two as negative controls.</p> <p>Results</p> <p>Two-dimensional gel electrophoresis was performed on each tissue and cell line protein sample. Principal component and cluster analysis revealed that global expression of intestinal epithelial scrapings differed from that of intestinal epithelial cell lines. Since all cultured cell lines clustered together, this finding was ascribed to an adaptation of cells to culture conditions and their tumor origin, and responsible proteins were identified by mass spectrometry. When investigating the profiles of Caco-2 cells and small intestinal cells in detail, a considerable overlap was observed.</p> <p>Conclusion</p> <p>Numerous proteins showed a similar expression in Caco-2 cells, HT-29 cells, and both the intestinal scrapings, of which some appear to be characteristic to human intestinal epithelium <it>in vivo</it>. In addition, several biologically significant proteins are expressed at comparable levels in Caco-2 cells and small intestinal scrapings, indicating the usability of this <it>in vitro </it>model. Caco-2 cells, however, appear to over-express as well as under-express certain proteins, which needs to be considered by scientists using this cell line. Hence, care should be taken to prevent misinterpretation of <it>in vitro </it>obtained findings when translating them to the <it>in vivo </it>situation.</p