Characterization of Filigree Additively Manufactured NiTi Structures Using Micro Tomography and Micromechanical Testing for Metamaterial Material Models

This study focuses on the influence of additive manufacturing process strategies on the specimen geometry, porosity, microstructure and mechanical properties as well as their impacts on the design of metamaterials. Filigree additively manufactured NiTi specimens with diameters between 180 and 350 µm and a nominal composition of Ni50.9Ti49.1 (at %) were processed by laser powder bed fusion in a first step. Secondly, they structures were characterized by optical and electron microscopy as well as micro tomography to investigate the interrelations between the process parameters, specimen diameters and microstructure. Each specimen was finally tested in a micro tensile machine to acquire the mechanical performance. The process strategy had, besides the resulting specimen diameter, an impact on the microstructure (grain size) without negatively influencing its quality (porosity). All specimens revealed a superelastic response while the critical martensitic phase transition stress decreased with the applied vector length. As a conclusion, and since the design of programmable metamaterials relies on the accuracy of FEM simulations, precise and resource-efficient testing of filigree and complex structures remains an important part of creating a new type of metamaterials with locally adjusted material behavior

Additive Manufacturing of Binary Ni–Ti Shape Memory Alloys Using Electron Beam Powder Bed Fusion: Functional Reversibility Through Minor Alloy Modification and Carbide Formation

Shape memory alloys (SMAs), such as Ni–Ti, are promising candidates for actuation and damping applications. Although processing of Ni–Ti bulk materials is challenging, well-established processing routes (i.e. casting, forging, wire drawing, laser cutting) enabled application in several niche applications, e.g. in the medical sector. Additive manufacturing, also referred to as 4D-printing in this case, is known to be highly interesting for the fabrication of SMAs in order to produce near-net-shaped actuators and dampers. The present study investigated the impact of electron beam powder bed fusion (PBF-EB/M) on the functional properties of C-rich Ni50.9Ti49.1 alloy. The results revealed a significant loss of Ni during PBF-EB/M processing. Process microstructure property relationships are discussed in view of the applied master alloy and powder processing route, i.e. vacuum induction-melting inert gas atomization (VIGA). Relatively high amounts of TiC, being already present in the master alloy and powder feedstock, are finely dispersed in the matrix upon PBF-EB/M. This leads to a local change in the chemical composition (depletion of Ti) and a pronounced shift of the transformation temperatures. Despite the high TiC content, superelastic testing revealed a good shape recovery and, thus, a negligible degradation in both, the as-built and the heat-treated state

Expression patterns of angiogenic and lymphangiogenic factors in ductal breast carcinoma in situ

The objective of this study was to investigate expression of various growth factors associated with angiogenesis and lymphangiogenesis and of their receptors in ductal carcinomas in situ of the breast (DCIS). We studied protein expression of basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF)-A, endothelin (ET)-1, and VEGF-C, and their receptors bFGF-R1, Flt-1, KDR, ETAR, ETBR, and Flt-4 immunohistochemically in 200 DCIS (pure DCIS: n=96; DCIS adjacent to an invasive component: n=104) using self-constructed tissue microarrays. Basic fibroblast growth factor-R1, VEGF-C, Flt-4, and ETAR were expressed in the tumour cells in the majority of cases, whereas bFGF and Flt-1 expression was rarely observed. VEGF-A, KDR, ET-1, and ETBR were variably expressed. The findings of VEGF-C and its receptor Flt-4 as lymphangiogenic factors being expressed in tumour cells of nearly all DCIS lesions and the observed expression of various angiogenic growth factors in most DCIS suggest that in situ carcinomas are capable of inducing angiogenesis and lymphangiogenesis. Moreover, we found a higher angiogenic activity in pure DCIS as compared to DCIS with concomitant invasive carcinoma. This association of angiogenic factors with pure DCIS was considerably more pronounced in the subgroup of non-high-grade DCIS (n=103) as compared with high-grade DCIS (n=94). Determination of these angiogenic markers may therefore facilitate discrimination between biologically different subgroups of DCIS and could help to identify a particularly angiogenic subset with a potentially higher probability of recurrence or of progression to invasiveness. For these DCIS, targeting angiogenesis may represent a feasible therapeutic approach for prevention of progression of DCIS to invasion

Das Vorkommen von CD44 und seinen Isoformen unter orthologischen und pathologischen Bedingungen = Occurrence of CD44 and its isoforms under orthological and pathological conditions

Variant isoforms of CD44 have been strongly implicated in malignant transformation and cancer metastasis. To ascertain the pattern of expression of these isoforms in human normal, fetal and tumor tissues (breast carcinomas, renal cell carcinomas, malignant melanomas, colon carcinomas, non-Hodgkin-lymphomas, neuroblastomas and brain tumors), we generated monoclonal antibodies against CD44 variant regions. Monoclonal antibodies were produced against variant regions encoded by exons 4v, 6v and 9v. CD44 variant isoforms are expressed on normal epithelial cells in a different pattern. Regions of epithelia that expressed the highest levels of the variant isoforms were those with a high rate of cell division. CD44 variant isoforms were not expressed by all investigated tumors (not by malignant melanomas, brain tumors and neuroblastomas). It is interesting that the expression of CD44 isoforms in non-Hodgkins lymphomas and colon carcinomas shows possibly a correlation with malignancy

Co-processing Plant Extracts for Improvement of Their Pharmacotechnic Properties

<p><span><strong>ABSTRACT: </strong>The herbal Espinheira Santa (Maytenus ilicifolia) can ingested in capsules for treatment of injuries from digestive tract, such as gastritis. However, the large amount of drug administered dose medication adherence difficult, so this study sought an alternative by formulating effervescent granules facilitating drug intake. The obtained granules made by wet and effervescent mixture of citric acid, sodium carbonate and sodium bicarbonate at different concentrations, totaling eight formulations, in addition to lactose as diluent and disintegrant in the composition. The granules were produced in sizes from 1 and 2mm. Rheological tests were compared against the dry extract, analyzed the average particle sizes of beads, mapped its surface by scanning electron microscopy and evaluated their behavior effervescent. The flow properties of the granules showed better values than the dry extract. The co-processed formulations showed average particle sizes distributed closed, where 1mm time effervescence had smaller, respecting all formulations, pharmacopeial limits of maximum 5 minutes. The preparation of effervescent granules Espinheira Santa proved to be a good alternativel, once that have easy preparation, low cost, excellent flow and rapid disintegration.</span></p><p><span><strong>Keywords:</strong> Espinheira Santa, effervescent granules, dry extract.</span></p