Auflistung nach Schlagwort "500 - Naturwissenschaften"

Gerade angezeigt 1 - 20 von 94

A new concept of liquid membranes in Taylor flow. Performance for lactic acid removal
(Elsevier, 05/2019) Pérez, Alan; Fontalvo, Javier
A liquid membrane in Taylor flow regime is a novel alternative kind of contact in three-phase flow for liquid membranes that preserves the advantages of conventional emulsion liquid membranes while overcomes the stability problems of emulsion systems. As a proof of concept, this work presents experimental results of a liquid membrane in Taylor flow for lactic acid removal. Several operating conditions, such as injection times, delay times and flow of the membrane phase were tested for a channel length and inner diameter of 348.8 cm and 2.5 mm, respectively. The lactic acid removal is mainly affected by the driving force of lactic acid concentrations between donor droplets and the membrane interface, and the space-time. Thus, the lactic acid removal process through the liquid membrane in Taylor flow is enhanced at low injection times and high droplet velocity considering that enough space-time is provided. This technology results promising as an alternative to conventional liquid membranes and the intensification of chemical and fermentative processes.
01A - Beitrag in wissenschaftlicher Zeitschrift
A review of more than 20 years of aerosol observation at the high altitude research station Jungfraujoch, Switzerland (3580 m asl)
(Taiwan Association for Aerosol Research, 2016) Bukowiecki, Nicolas; Weingartner, Ernest; Gysel, Martin; Coen, Martine Collaud; Zieger, Paul; Herrmann, Erik; Steinbacher, Martin; Gäggeler, Heinz W.; Baltensperger, Urs
01A - Beitrag in wissenschaftlicher Zeitschrift
Adaptive immune receptor repertoire (AIRR) community guide to TR and IG gene annotation
(Springer, 28.05.2022) Babrak, Lmar; Marquez, Susanna; Busse, Christian; Lees, William; Miho, Enkelejda; Ohlin, Mats; Rosenfeld, Aaron; Stervbo, Ulrik; Watson, Corey; Schramm, Chaim; Langerak, Anton W.
High-throughput sequencing of adaptive immune receptor repertoires (AIRR, i.e., IG and TR) has revolutionized the ability to carry out large-scale experiments to study the adaptive immune response. Since the method was first introduced in 2009, AIRR sequencing (AIRR-Seq) has been applied to survey the immune state of individuals, identify antigen-specific or immune-state-associated signatures of immune responses, study the development of the antibody immune response, and guide the development of vaccines and antibody therapies. Recent advancements in the technology include sequencing at the single-cell level and in parallel with gene expression, which allows the introduction of multi-omics approaches to understand in detail the adaptive immune response. Analyzing AIRR-seq data can prove challenging even with high-quality sequencing, in part due to the many steps involved and the need to parameterize each step. In this chapter, we outline key factors to consider when preprocessing raw AIRR-Seq data and annotating the genetic origins of the rearranged receptors. We also highlight a number of common difficulties with common AIRR-seq data processing and provide strategies to address them.
04A - Beitrag Sammelband
Advancing Raman model calibration for perfusion bioprocesses using spiked harvest libraries
(Wiley, 07.08.2022) Kolar, Jakub; Herwig, Christoph; Bielser, Jean‐Marc; Romann, Patrick; Tobler, Daniela; Villiger, Thomas
Background Raman spectroscopy has gained popularity to monitor multiple process indicators simultaneously in biopharmaceutical processes. However, robust and specific model calibration remains a challenge due to insufficient analyte variability to train the models and high cross-correlation of various media components and artifacts throughout the process. Main Methods A systematic Raman calibration workflow for perfusion processes enabling highly specific and fast model calibration was developed. Harvest libraries consisting of frozen harvest samples from multiple CHO cell culture bioreactors collected at different process times were established. Model calibration was subsequently performed in an offline setup using a flow cell by spiking process harvest with glucose, raffinose, galactose, mannose, and fructose. Major Results In a screening phase, Raman spectroscopy was proven capable not only to distinguish sugars with similar chemical structures in perfusion harvest but also to quantify them independently in process-relevant concentrations. In a second phase, a robust and highly specific calibration model for simultaneous glucose (root mean square error prediction [RMSEP] = 0.32 g L−1) and raffinose (RMSEP = 0.17 g L−1) real-time monitoring was generated and verified in a third phase during a perfusion process. Implication The proposed novel offline calibration workflow allowed proper Raman peak decoupling, reduced calibration time from months down to days, and can be applied to other analytes of interest including lactate, ammonia, amino acids, or product titer. Graphical Abstract and Lay Summary Building accurate and robust Raman models for online monitoring of cell culture processes remains a difficult and time-consuming process, particularly for perfusion processes. In this study, the authors developed a novel offline calibration approach based on design-of-experiment spiking and a harvesting library. The Raman spectra of these spiked harvest samples allowed proper peak decoupling and model generation within days instead of weeks or even months. The approach has been successfully applied to monitor various sugars in perfusion bioreactors and other compounds as well as process modes may equally benefit from the described workflow.
01A - Beitrag in wissenschaftlicher Zeitschrift
Alexander von Humboldt als Vorbild für naturwissenschaftliches Lernen
(Universität Regensburg, 2020) Schumann, Svantje; Gröger, Martin; Heck, Volker; Schwarz, Oliver; Maurer, Christian
Ausgehend von Reflexionen zu Humboldts wissenschaftlicher und kameralistischer Methodik sowie seinen Arbeitsergebnissen in den verschiedenen Fachbereichen werden Bezüge zum heutigen Sachunterricht und zum naturwissenschaftlichen Unterricht hergestellt. Hierbei wird unter dem Aspekt einer Bildung zu nachhaltiger Entwicklung Humboldts Forschungsansatz der Natur- und Wirtschaftsraumbilanzierung betrachtet. Einige Verfahren und Experimente in den Forschungsbereichen Astronomie, Biologie, Chemie, Geografie und Physik werden nachvollzogen und aus heutiger Perspektive reflektiert. Hierzu werden Rückschlüsse insbesondere auf fächerverbindendes Lernen, forschend-entdeckendes Lernen und den Einbezug von Aspekten der Natur der Naturwissenschaften (NOS) vorgestellt, auch für die Aus- und Weiterbildung von Lehrpersonen.
04B - Beitrag Konferenzschrift
Anmerkungen zur Novellierung der Strahlenschutzverordnung
(02/2016) Dorusch, Falk
06 - Präsentation
Assessing the biodegradation of btex and stress response in a bio-permeable reactive barrier using compound-specific isotope analysis
(MDPI, 20.07.2022) Chen, Tianyu; Wu, Yan; Wang, Jinnan; Corvini, Philippe
By using compound-specific isotope analysis (CSIA) in combination with high-throughput sequencing analysis (HTS), we successfully evaluated the benzene and toluene biodegradation in a bio-permeable reactive barrier (bio-PRB) and the stress response of the microbial community. Under stress conditions, a greater decline in the biodegradation rate of BTEX was observed compared with the apparent removal rate. Both an increase in the influent concentration and the addition of trichloroethylene (TCE) inhibited benzene biodegradation, while toluene biodegradation was inhibited by TCE. Regarding the stress response, the relative abundance of the dominant bacterial community responsible for the biodegradation of BTEX increased with the influent concentration. However, the dominant bacterial community did not change, and its relative abundance was restored after the influent concentration decreased. On the contrary, the addition of TCE significantly changed the bacterial community, with Aminicenantes becoming the dominant phyla for co-metabolizing TCE and BTEX. Thus, TCE had a more significant influence on the bio-PRB than an increasing influent concentration, although these two stress conditions showed a similar degree of influence on the apparent removal rate of benzene and toluene. The present work not only provides a new method for accurately evaluating the biodegradation performance and microbial community in a bio-PRB, but also expands the application of compound-specific isotope analysis in the biological treatment of wastewater.
01A - Beitrag in wissenschaftlicher Zeitschrift
Automatic landmark identification for surgical 3d-navigation – A proposed method for marker-free dental surgical navigation systems
(De Gruyter, 04.07.2022) Bischofberger, Micha; Schkommodau, Erik; Böhringer, Stephan
This paper proposes a conceptual method to calculate the pose of a stereo-vision camera relative to an artificial mandible without additional markers. The general method for marker-free navigation has four steps: 1) parallel image acquisition by a stereo-vision camera, 2) automatic identification of 2d point pairs (landmark pairs) in a left and a right image, 3) calculation of related 3d points in the joint camera coordinate system and 4) matching of 3d points generated to a preoperative 3d model (i.e., CT data based). To identify and compare landmarks in the acquired stereo images, well-known algorithms for landmark detection, description and matching were compared within the developed approach. Finally, the BRISK algorithm (Leutenegger S, Chli M, Siegwart RY. BRISK: Binary Robust invariant scalable keypoints. Proceedings of the IEEE International Conference on Computer Vision; 2011: 2548–2555) was used. The proposed method was implemented in MATLAB and validated with one artificial mandible. The accuracy evaluation of the camera positions calculated resulted in an average deviation error of 1.45 mm ± 0.76 mm to the real camera displacement. This value was calculated using only stereo images with over 100 reconstructed landmark pairs each. This provides the basis for marker-free navigation.
01A - Beitrag in wissenschaftlicher Zeitschrift
Beispiele für gelungenen Transfer im Bereich Naturwissenschaften in der Schweiz
(19.03.2019) Metzger, Susanne
06 - Präsentation
Characterization of a cotton-wool like composite bone graft material
(Springer, 18.07.2022) Rohr, Nadja; Brunner, Claudia; Bellon, Benjamin; Fischer, Jens; de Wild, Michael
Bone graft materials are applied in patients to augment bone defects and enable the insertion of an implant in its ideal position. However, the currently available augmentation materials do not meet the requirements of being completely resorbed and replaced by new bone within 3 to 6 months. A novel electrospun cotton-wool like material (Bonewool, Zurich Biomaterials LLC, Zurich, Switzerland) consisting of biodegradable poly(lactic-co-glycolic) acid (PLGA) fibers with incorporated amorphous ß-tricalcium phosphate (ß-TCP) nanoparticles has been compared to a frequently used bovine derived hydroxyapatite (Bio-Oss, Geistlich Pharma, Wolhusen, Switzerland) in vitro. The material composition was determined and the degradation behavior (calcium release and pH in different solutions) as well as bioactivity has been measured. Degradation behavior of PLGA/ß-TCP was generally more progressive than for Bio-Oss, indicating that this material is potentially completely resorbable.
01A - Beitrag in wissenschaftlicher Zeitschrift
Chemical and physical influences on aerosol activation in liquid clouds. A study based on observations from the Jungfraujoch, Switzerland
(Copernicus, 2016) Hoyle, Christopher R.; Webster, Clare S.; Rieder, Harald E.; Nenes, Athanasios; Hammer, Emanuel; Herrmann, Erik; Gysel, Martin; Bukowiecki, Nicolas; Weingartner, Ernest; Steinbacher, Martin; Baltensperger, Urs
A simple statistical model to predict the number of aerosols which activate to form cloud droplets in warm clouds has been established, based on regression analysis of data from four summertime Cloud and Aerosol Characterisation Experiments (CLACE) at the high-altitude site Jungfraujoch (JFJ). It is shown that 79 % of the observed variance in droplet numbers can be represented by a model accounting only for the number of potential cloud condensation nuclei (defined as number of particles larger than 80 nm in diameter), while the mean errors in the model representation may be reduced by the addition of further explanatory variables, such as the mixing ratios of O3, CO, and the height of the measurements above cloud base. The statistical model has a similar ability to represent the observed droplet numbers in each of the individual years, as well as for the two predominant local wind directions at the JFJ (northwest and southeast). Given the central European location of the JFJ, with air masses in summer being representative of the free troposphere with regular boundary layer in-mixing via convection, we expect that this statistical model is generally applicable to warm clouds under conditions where droplet formation is aerosol limited (i.e. at relatively high updraught velocities and/or relatively low aerosol number concentrations). A comparison between the statistical model and an established microphysical parametrization shows good agreement between the two and supports the conclusion that cloud droplet formation at the JFJ is predominantly controlled by the number concentration of aerosol particles.
01A - Beitrag in wissenschaftlicher Zeitschrift
Comparison of plasma ionization- and secondary electrospray ionization- high-resolution mass spectrometry for real-time breath analysis
(Schweizerische Chemische Gesellschaft, 23.02.2022) Zeng, Jiafa; Christen, Alexandra; Dev Singh, Kapil; Frey, Urs; Sinues, Pablo
Real-time breath analysis by high-resolution mass spectrometry (HRMS) is a promising method to noninvasively retrieve relevant biochemical information. In this work, we conducted a head-to-head comparison of two ionization techniques: Secondary electrospray ionization (SESI) and plasma ionization (PI), for the analysis of exhaled breath. Two commercially available SESI and PI sources were coupled to the same HRMS device to analyze breath of two healthy individuals in a longitudinal study. We analyzed 58 breath specimens in both platforms, leading to 2,209 and 2,296 features detected by SESI-HRMS and by PI-HRMS, respectively. 60% of all the mass spectral features were detected in both platforms. However, remarkable differences were noted in terms of the signal-to-noise ratio (S/N), whereby the median (interquartile range, IQR) S/N ratio for SESI-HRMS was 115 (IQR = 408), whereas for PI-HRMS it was 5 (IQR = 5). Differences in the mass spectral profiles for the same samples make the inter-comparability of both techniques problematic. Overall, we conclude that both techniques are excellent for real-time breath analysis because of the very rich mass spectral fingerprints. However, further work is needed to fully understand the exact metabolic insights one can gather using each of these platforms.
01A - Beitrag in wissenschaftlicher Zeitschrift
Competence Models for Science in Switzerland
(22.08.2017) Metzger, Susanne; Gut, Christoph
Within the Swiss project HarmoS (harmonization of the compulsory school) an interdisciplinary structural model of competence has been developed. Based on this model, progressions focused on science processes such as “to ask questions and to investigate”, “to exploit information sources”, “to organise, structure and model”, “to assess and judge”, and “to develop and realise” have been described and validated empirically (Labudde, 2008). From these results, nationwide basic performance standards for science for the end of grades 2, 6, and 9 have been derived (Labudde, Nidegger, Adamina & Gingins, 2012). The achievement of the standards should be checked regularly in national education monitoring. In addition, an interdisciplinary normative progression model for experimental competence has been worked out for practical assessments (Metzger, Gut, Hild & Tardent, 2014). In this model, experimental competence is structured by sub-dimensions referring to experimental problem types such as “categorical observation”, “measurement with a given scale”, “scientific investigation” and “constructive problem solving”. The progression of competence is modelled for each problem type separately, differentiating three to five levels in terms of quality standards. Based on the progressions used to define the basic performance standards, detailed progressions of levels of competence were described in a new curriculum (“Lehrplan 21”: D-EDK, 2016). In this paper, the two competence models and associated progressions are presented. Even if these progressions are focused on the students’ abilities, there are no references how students can reach the next level. Therefore the connection between competence models and curriculum with teaching still needs to be established. It will be discussed how this can be achieved and what steps are necessary to get from competence models to learning progressions.
06 - Präsentation
Concept Cartoons und gestufte Lernhilfen als Lernunterstützungen beim forschenden Experimentieren
(18.02.2018) Arnold, Julia
06 - Präsentation
Contribution of railway traffic to local PM10 concentrations in Switzerland
(Elsevier, 02/2007) Gehrig, Robert; Hill, Matz; Lienemann, Peter; Zwicky, Christoph N.; Bukowiecki, Nicolas; Weingartner, Ernest; Baltensperger, Urs; Buchmann, Brigitte
Field measurement campaigns of PM10 and its elemental composition (daily sampling on filters) covering different seasons were performed at two sites near the busiest railway station of Switzerland in Zurich (at a distance of 10 m from the tracks) and at a site near a very busy railway line with more than 700 trains per day. At this latter site parallel samples were taken at 10, 36 and 120 m distances from the tracks with the aim to study the distance dependence of the railway induced PM10 concentrations. To distinguish the relatively small railway emissions from the regional background (typically 20–25 μg m−3), simultaneous samples were also taken at an urban background site in Zurich. The differences in PM10 and elemental concentrations between the railway exposed sites and the background site were allocated to the railway contribution. Small, however, measurable PM10 concentration differences were found at all sites. The elemental composition of these differences revealed iron as the only quantitatively important constituent. As a long-term average it amounted to approximately 1 μg m−3 Fe at a distance of 10 m from the tracks at all three sites. Assuming that iron was at least partly oxidised (e.g. in the form of Fe2O3) the contribution can amount up to 1.5 μg m−3. Emissions of copper, manganese and chromium from trains were also clearly identified. However, compared to iron these, elements were emitted in very low quantities. No significant contribution from rock material (calcium, aluminium, magnesium, sodium) was observed as might have been expected from erosion, abrasion and resuspension from the gravel below the tracks. Particle emissions from diesel exhaust were not considered as trains in Switzerland are operated nearly exclusively by electric locomotives. The railway, induced contribution to ambient PM10 decreased rapidly with increasing distance from the tracks. At a distance of 120 m this contribution dropped to only 25% of the contribution observed at 10 m distance.
01A - Beitrag in wissenschaftlicher Zeitschrift
Deep brain stimulation: emerging tools for simulation, data analysis, and visualization
(Frontiers, 11.04.2022) Wårdell, Karin; Nordin, Teresa; Zsigmond, Peter; Westin, Carl-Fredrik; Hariz, Marwan; Vogel, Dorian; Hemm-Ode, Simone
Deep brain stimulation (DBS) is a well-established neurosurgical procedure for movement disorders that is also being explored for treatment-resistant psychiatric conditions. This review highlights important consideration for DBS simulation and data analysis. The literature on DBS has expanded considerably in recent years, and this article aims to identify important trends in the field. During DBS planning, surgery, and follow up sessions, several large data sets are created for each patient, and it becomes clear that any group analysis of such data is a big data analysis problem and has to be handled with care. The aim of this review is to provide an update and overview from a neuroengineering perspective of the current DBS techniques, technical aids, and emerging tools with the focus on patient-specific electric field (EF) simulations, group analysis, and visualization in the DBS domain. Examples are given from the state-of-the-art literature including our own research. This work reviews different analysis methods for EF simulations, tractography, deep brain anatomical templates, and group analysis. Our analysis highlights that group analysis in DBS is a complex multi-level problem and selected parameters will highly influence the result. DBS analysis can only provide clinically relevant information if the EF simulations, tractography results, and derived brain atlases are based on as much patient-specific data as possible. A trend in DBS research is creation of more advanced and intuitive visualization of the complex analysis results suitable for the clinical environment.
01A - Beitrag in wissenschaftlicher Zeitschrift
Delignification of low-energy mechanical pulp (asplund fibers) in a deep eutectic solvent system of choline chloride and lactic acid
(Frontiers Research Foundation, 09.06.2021) Pérez, Alan; Fiskari, Juha; Schuur, Boelo
Deep eutectic solvents (DESs) are considered as a green and environmentally benign solvent class for various applications, including delignification of biomass. One of the major challenges in the delignification of biomass by DES is attributed to the limitations in mass transfer. By subjecting wood chips to a low-energy mechanical refining, i.e., the Asplund process, the accessible surface area increases greatly, which in turn improves the mass transfer and increases the reaction rate. In this research, the DES delignification of Asplund fibers made of Norway spruce was studied as a strategy to produce papermaking fibers under mild conditions. A DES consisting of lactic acid and choline chloride was used due to its proven performance in delignification. Various operational conditions, such as temperature, time, DES-to-wood ratio, and the type of stirring were studied. A novel parameter, Q, allowed to evaluate the impact of the operational conditions on the quality of the pulp in terms of delignification degree and fiber length. The results showed that cooking temperature had the most significant effect on the pulp quality. Additionally, it was observed that cooking times between 30 and 45 min result in a pulp yield of about 50%, while fibers have a lignin content of about 14% and a fiber length of 0.6 mm. These results demonstrate that it is possible to obtain fibers of relatively good quality from DES delignification using Asplund fibers as the starting material.
01A - Beitrag in wissenschaftlicher Zeitschrift
Denken und Verstehen beim naturwissenschaftlichen Problemlösen - eine explorative Studie
(Barbara Budrich, 2013) Völzke, Katja; Arnold, Julia; Kerstin, Kremer
01A - Beitrag in wissenschaftlicher Zeitschrift
Development of a new reactor concept for oxidation reactions
(Hochschule für Life Sciences FHNW, 2023) Lamanna Bürkler, Patrizia; Zogg, Andreas; DSM-Firmenich
Oxidation reactions comprises an important class of reactions. One key commercial product in DSM – Firmenich' s portfolio contains an oxidation step using 100% O2. Oxidation reactions are highly exothermic, often operated in an organic solvent. With a possible ignition source, this will lead to a high-risk potential regarding explosion. To obtain a safe process, it is desirable to avoid an explosive atmosphere, but this will cause limitations regarding process temperature and pressure. In reactions with 100% O2, very high explosion pressures must be expected. An inherently safe mode of operation is only possible if the apparatus were constructed to be pressure shock resistant and the process temperature is kept between a certain range. The goal of this master thesis is the development of a new reactor concept for gas-liquid phase reactions with focus on oxidation reactions. Based on the design of a loop-reactor, the gaseous oxidizing agent O2 is transferred to the liquid reaction mass using membrane technology. The concept keeps the liquid phase saturated with O2, while minimizing the creation of an explosive atmosphere inside the reactor. The approach of a head space free reactor is a significantly increase of process safety while minimizing the constraints with regards to the solvent selection and process conditions.
11 - Studentische Arbeit
Development of a setup to study electrostatic discharges
(Hochschule für Life Sciences FHNW, 2023) Brönnimann, Benedikt; Zogg, Andreas
Two glass lined reactors in a launch platform facility operated by Syngenta have been damaged during a crystallization-process of an organic compound due to electrostatic discharges. The goal of this thesis was to design and commission a unique setup to measure charges and currents generated by such suspensions in a laboratory-scale reactor. These measurements made it possible to then calculate and estimate resulting discharge energies. An improved and more sophisticated setup was then proposed for possible implementation in their own laboratories. With this novel setup, the electrostatic charging of stirred suspensions involving non conductive solvents could be accurately measured in the context of a case study that involved the suspension that led to liner damages in the production facilities of Syngenta.
11 - Studentische Arbeit