A novel polysaccharide/zein conjugate as an alternative green plastic.

The flax seed cake is a waste product from flax oil extraction. Adding value to this wasted material aligns with the concept of circularity. In this study, we explored zein protein conjugation with flax mucilage for packaging material development. Although both flax mucilage and zein have excellent film-forming properties, they lack the required mechanical properties for industrial processing and are sensitive to high humidity. We present a simple and non-toxic one-pot method for developing the novel flax mucilage/zein conjugate. Where the flax mucilage undergoes oxidation to form aldehyde groups, which then react with zein's amino groups in a glycation process. The conjugates were analyzed using different techniques. The flax mucilage conjugate had a water-holding capacity of 87-62%. Increasing the zein content improved the surface smoothness of the films. On the other hand, higher levels of zein led to a significant decrease in film solubility (p < 0.05). The flax mucilage conjugate exhibited thermoplastic and elastic properties; revealing Young's modulus of 1-3 GPa, glass transition temperature between 49 °C and 103 °C and excellent processability with various industrial techniques. Showing its potential as a sustainable alternative to traditional plastics.

An Edge-Filtered Optical Fiber Interrogator for Thermoplastic Polymer Analysis.

The present paper deals with the determination of thermodynamic quantities of thermoplastic polymers by using an optical fiber interrogator. Typically, laboratory methods such as differential scanning calorimetry (DSC) or thermomechanical analysis (TMA) are a reliable state-of-the-art option for thermal polymer analysis. The related laboratory commodities for such methods are of high cost and are impractical for field applications. In this work, an edge-filter-based optical fiber interrogator, which was originally developed to detect the reflection spectrum of fiber Bragg grating sensors, is utilized for the detection of the boundary reflection intensities of the cleaved end of a standard telecommunication optical fiber (SMF28e). By means of the Fresnel equations, the temperature-dependent refractive index of thermoplastic polymer materials is measured. Demonstrated with the amorphous thermoplastic polymers polyetherimide (PEI) and polyethersulfone (PES), an alternative to DSC and TMA is presented as the glass transition temperatures and coefficients of thermal expansion are derived. A DSC alternative in the semi-crystalline polymer analysis with the absence of a crystal structure is shown as the melting temperature and cooling-rate-dependent crystallization temperatures of polyether ether ketone (PEEK) are detected. The proposed method shows that thermal thermoplastic analysis can be performed with a flexible, low-cost and multipurpose device.

Bringing Light into the Dark-Overview of Environmental Impacts of Carbon Fiber Production and Potential Levers for Reduction.

Carbon fibers (CFs) are a crucial material for lightweight structures with advanced mechanical performance. However, there is still a paucity of detailed understanding regarding the environmental impacts of production. Previously, mostly singled-out scenarios for CF production have been assessed, often based on scarce transparent inventory data. To expand the current knowledge and create a robust database for future evaluation, a life cycle assessment (LCA) was carried out. To this end, a detailed industry-approved LCI is published, which also proved plausible against the literature. Subsequently, based on a global scenario representing the market averages for precursor and CF production, the most relevant contributors to climate change (EF3.1 climate change, total) and the depletion of fossil energy carriers (EF3.1 resource use, fossil) were identified. The energy consumption in CF manufacturing was found to be responsible for 59% of the climate change and 48% of the fossil resource use. To enable a differentiated discussion of manufacturing locations and process energy consumption, 24 distinct scenarios were assessed. The findings demonstrate the significant dependence of the results on the scenarios' boundary conditions: climate change ranges from 13.0 to 34.1 kg CO2 eq./kg CF and resource use from 262.3 to 497.9 MJ/kg CF. Through the investigated scenarios, the relevant reduction potentials were identified. The presented results help close an existing data gap for high-quality, regionalized, and technology-specific LCA results for the production of CF.

Foundational Investigation on the Characterization of Porosity and Fiber Orientation Using XCT in Large-Scale Extrusion Additive Manufacturing.

The great potential of Extrusion Additive Manufacturing (EAM) for structural prototyping in the automotive industry is severely limited by the directional bias in the build direction. The layerwise fabrication leads to reduced mechanical properties at the layer-to-layer interface compared to the bulk of the strand. Especially for the often-used semi-crystalline thermoplastics, the mechanical properties strongly depend on the processing parameters, even more so if short fibers are used as fillers. Therefore, ideal processing windows in which the mechanical strength and modulus in the z-direction reach their maximum can be identified for these parameters, resulting in a reduced directional bias. The influence of the EAM processing parameters on mechanical strength has already been investigated, correlating strength with thermal conditions during printing. However, these considerations did not distinguish between the thermal effect on the polymer properties, the formation of voids and pores at the layer interface, and the resulting fiber orientation for different strand proportions. Therefore, in this study, the effect of different processing temperatures and layer heights on the pore size and distribution, as well as the fiber orientation in the different regions of the mesostructure was investigated using X-ray Computed Tomography (XCT).

Effect of Extrusion Parameters on Short Fiber Alignment in Fused Filament Fabrication.

Additive manufacturing by material extrusion such as the widespread fused filament fabrication is able to improve 3D printed part performance by using short fiber reinforced composite materials. Fiber alignment is critical for the exploitation of their reinforcing effect. This work investigates the influence extrusion parameters have on the fiber alignment by conducting set of experiments on the process parameters determining whether the flow under the nozzle is convergent or divergent. A strong impact of flow conditions during extrusion line shaping on the fiber alignment is observed and two extremes are tested which show a large difference in strength, stiffness and strain at break in tensile testing along the extrusion lines. From highest to lowest fiber alignment, strength is reduced by 41% and stiffness by 54%. Fiber misalignment also leads to inhomogeneous strain fields in the layers when tested perpendicular to the extrusion lines. It is demonstrated that material flow after the nozzle has a high impact on the material properties of short fiber reinforced 3D printed parts and needs to be considered in process design.

Antimicrobial and physicochemical characterization of 2,3-dialdehyde cellulose-based wound dressings systems.

Biobased and biodegradable films were prepared by physically mixing 2,3-dialdehyde cellulose (DAC) with two other biopolymers, zein and gelatin, in three different proportions. The antimicrobial activities of the composite blends against Gram-positive and Gram-negative bacteria increase with the increase of DAC content. Cell viability tests on mammalian cells showed that the materials were not cytotoxic. In addition, DAC and gelatin were able to promote thermal degradation of the blends. However, DAC increased the stiffness and decreased the glass transition temperature of the blends, while gelatin was able to decrease the stiffness of the film. Morphological analysis showed the effect of DAC on the surface smoothness of the blends. The contact angle confirmed that all blends were within the range of hydrophilic materials. Although all the blends showed impressive performance for wound dressing application, the blend with gelatin might be more suitable for this purpose due to its better mechanical performance and antibacterial activity.

Accurate Physics-Based Registration for the Outcome Validation of Minimal Invasive Interventions and Open Liver Surgeries.

OBJECTIVE: The purpose of this paper is to present an outcome validation tool for tumor radiofrequency (RF) ablation and resection. METHODS: Intervention assessment tools require an accurate registration of both pre- and postoperative computed tomographies able to handle big deformations. Therefore, a physics-based method is proposed with that purpose. To increase the accuracy both automatically detected internal and surface physical landmarks are incorporated in the registration process. RESULTS: The algorithm has been evaluated in 25 clinical datasets containing RF ablations, resections, and patients with recurrent tumors. The achieved accuracy is 1.2 mm measured as mean internal distance between vessel landmarks and a positive predictive value of 0.95. The quantitative and qualitative results of the outcome validation tool show that in 50% of the cases tumors were only partially covered by the treatment. CONCLUSION: The use of internal and surface landmarks combined with a physics-based registration method increases the accuracy of the results compared to the accuracy of state of the art methods. An accurate outcome validation tool is important in order to certify that the tumor and its safety margin were fully covered by the treatment. SIGNIFICANCE: An accurate outcome validation tool can result in a decrease of the tumor recurrence rate.

Model-based pancreas segmentation in portal venous phase contrast-enhanced CT images.

This study aims to automatically detect and segment the pancreas in portal venous phase contrast-enhanced computed tomography (CT) images. The institutional review board of the University of Erlangen-Nuremberg approved this study and waived the need for informed consent. Discriminative learning is used to build a pancreas tissue classifier incorporating spatial relationships between the pancreas and surrounding organs and vessels. Furthermore, discrete cosine and wavelet transforms are used to build texture features to describe local tissue appearance. Classification is used to guide a constrained statistical shape model to fit the data. The algorithm to detect and segment the pancreas was evaluated on 40 consecutive CT data that were acquired in the portal venous contrast agent phase. Manual segmentation of the pancreas was carried out by experienced radiologists and served as reference standard. Threefold cross validation was performed. The algorithm-based detection and segmentation yielded an average surface distance of 1.7 mm and an average overlap of 61.2 % compared with the reference standard. The overall runtime of the system was 20.4 min. The presented novel approach enables automatic pancreas segmentation in portal venous phase contrast-enhanced CT images which are included in almost every clinical routine abdominal CT examination. Reliable pancreatic segmentation is crucial for computer-aided detection systems and an organ-specific decision support.

Interventional planning of liver resections: an overview.

Liver cancer is the third most common type of cancer. Among available treatment options, a surgical resection offers the best prognosis for long-term survival. It is important that such a surgical procedure is carefully prepared. Modern computer technology offers convenient ways to simulate different resection scenarios and help to determine the best treatment for a given case. This paper provides a non-exhaustive overview of existing computer-based systems for interventional planning of liver resections. They are reviewed according to their medical use case, e.g. if they support typical or atypical resections.

HMGA2 expression in uterine leiomyomata and myometrium: quantitative analysis and tissue culture studies.

The high mobility group gene, HMGA2, is frequently expressed in uterine leiomyomata (UL) with chromosomal rearrangements of 12q15. In contrast, HMGA2 expression has not been detected in karyotypically normal UL or in myometrium, but has been detected in these tissues after culture. To characterize further the expression pattern of HMGA2, we assessed HMGA2 expression by RT-PCR followed by Southern blot hybridization, and by real-time PCR in three tissue panels: (1) primary myometrial cultures, (2) uncultured tissue from 15 karyotypically normal samples consisting of eleven 46,XX UL and four matched myometrial specimens, and (3) uncultured tissue from ten UL with 12q15 rearrangements and three matched myometrial specimens. HMGA2 expression was detected in all samples from the three panels. The level of HMGA2 expression in karyotypically normal UL was similar to the level of expression in myometrium; however, it was significantly less than the level measured in UL with 12q15 rearrangements. This expression analysis by use of detection methods of different sensitivities underscores the importance of studies of HMGA2 expression in uncultured tissues and of careful interpretation of results from experiments on cultured cells. Moreover, detection of HMGA2 expression in myometrium and in UL without 12q15 rearrangements, tissues previously thought not to express HMGA2, suggests that HMGA2 expression is required in normal adult myometrial physiology.