Auflistung nach Schlagwort "500 - Naturwissenschaften und Mathematik"

Gerade angezeigt 1 - 20 von 110

18HLT02 AeroToX: Measurements for mitigating adverse health effects from atmospheric particulate pollutants
A 17 month climatology of the cloud condensation nuclei number concentration at the high alpine site Jungfraujoch
(Wiley, 24.05.2011) Jurányi, Zsófia; Gysel, Martin; Weingartner, Ernest; Bukowiecki, Nicolas; Kammermann, Lorenz; Baltensperger, Urs
Between May 2008 and September 2009 the cloud condensation nuclei (CCN) number concentration, NCCN, was measured at the high alpine site Jungfraujoch, which is located in the free troposphere most of the time. Measurements at 10 different supersaturations (0.12%–1.18%) were made using a CCN counter (CCNC). The monthly median NCCN values show a distinct seasonal variability with ∼5–12 times higher values in summer than in winter. The major part of this variation can be explained by the seasonal amplitude of total aerosol number concentration (∼4.5 times higher values in summer), but it is further amplified (factor of ∼1.1–2.6) by a shift of the particle number size distribution toward slightly larger sizes in summer. In contrast to the extensive properties, the monthly median of the critical dry diameter, above which the aerosols activate as CCN, does not show a seasonal cycle (relative standard deviations of the monthly median critical dry diameters at the different supersaturations are 4–9%) or substantial variability (relative standard deviations of individual data points at the different supersaturations are less than 18–37%). The mean CCN-derived hygroscopicity of the aerosol corresponds to a value of the hygroscopicity parameter κ of 0.20 (assuming a surface tension of pure water) with moderate supersaturation dependence. NCCN can be reliably predicted throughout the measurement period with knowledge of the above-mentioned averaged κ value and highly time-resolved (∼5 min) particle number size distribution data. The predicted NCCN was within 0.74 to 1.29 times the measured value during 80% of the time (94,499 data points in total at 10 different supersaturations).
01A - Beitrag in wissenschaftlicher Zeitschrift
A method and tool for strategic hospital planning
(Springer, 2015) Brodbeck, Dominique; Degen, Markus; Walter, Andreas; Reichlin, Serge; Napierala, Christoph; Fred, Ana; Gamboa, Hugo; Elias, Dirk
We developed a visualization tool and a methodology to support strategic planning of hospital service portfolios. Hospitals in Switzerland are reimbursed with a fixed fee per case. The fixed-fee model makes medical services comparable from a financial point of view. In order to take advantage of this model, the data that characterizes the medical services must be operationalized. The method that we developed, centers around a visual metaphor that provides the basis for strategic thinking. It is complemented by a visualization tool that allows visualization, analysis, and modification of service portfolios. Special features enable the tool to be used during live planning sessions. We describe the method, the tool, and its application in strategy workshops for infrastructure planning, reorganization, and resource optimization decisions.
04B - Beitrag Konferenzschrift
A mobile collaboration and decision support system for the medical emergency departement
(SciTePress, 2012) Brodbeck, Dominique; Degen, Markus; Reiss, Maximilian; Conchon, Emmanuel; Correia, Carlos; Fred, Ana; Gamboa, Hugo
A hospital emergency department is a complex work environment, where the availability of the right information at the right time is crucial for efficient and safe operation. The current technology in use for communication and information management is mostly based on telephones and stationary personal computers. Modern smartphones with their computational power, voice, image, and video capabilities have the potential to play a significant role in improving the flow of information in the emergency department. We developed a system that explicitly supports the work flows of an emergency department. In addition to mobile access to patient data and notifications about the availability of diagnostic findings, it provides the possibility to supply media captured on-site to the patient record, and directly supports the consultation process.
04B - Beitrag Konferenzschrift
A novel concept combining experimental and mathematical analysis for the identification of unknown interspecies effects in a mixed culture
(Wiley, 08/2011) Schmidt, Julia K.; Riedele, Christian; Regestein, Lars; Rausenberger, Julia; Reichl, Udo
Bacteria in natural habitats only occur in consortia together with various other species. Characterization of bacterial species, however, is normally done by laboratory testing of pure isolates. Any interactions that might appear during growth in mixed-culture are obviously missed by this approach. Existing experimental studies mainly focus on two-species mixed cultures with species specifically chosen for their known growth characteristics, and their anticipated interactions. Various theoretical mathematical studies dealing with mixed cultures and possible interspecies effects exist, but often models cannot be validated due to a lack of experimental data. Here, we present a concept for the identification of interspecies effects in mixed cultures with arbitrary and unknown single-species properties. Model structure and parameters were inferred from single-species experiments for the reproduction of mixed-culture experiments by simulation. A mixed culture consisting of the three-species Pseudomonas aeruginosa, Burkholderia cepacia, and Staphylococcus aureus served as a model system. For species-specific enumeration a quantitative terminal restriction length polymorphism (qT-RFLP) assay was used. Based on models fitted to single-species cultivations, the outcome of mixed-culture experiments was predicted. Deviations of simulation results and experimental findings were then used to design additional single-cell experiments, to modify the corresponding growth kinetics, and to update model parameters. Eventually, the resulting mixed-culture dynamics was predicted and compared again to experimental results. During this iterative cycle, it became evident that the observed coexistence of P. aeruginosa and B. cepacia in mixed-culture chemostat experiments cannot be explained on the basis of glucose as the only substrate. After extension of growth kinetics, that is, for use of amino acids as secondary substrates, mixed-culture simulations represented the experimental findings very well. According to the model structure, as motivated by single-species experiments, the growth of P. aeruginosa and B. cepacia on glucose and amino acids could be assumed to be independent of each other. In contrast, both substrates are taken up simultaneously by S. aureus.
01A - Beitrag in wissenschaftlicher Zeitschrift
A perfused in vitro human iPSC-derived blood–brain barrier faithfully mimics transferrin receptor-mediated transcytosis of therapeutic antibodies
(Springer, 2023) Burgio, Floriana; Gaiser, Carine; Brady, Kevin; Gatta, Viviana; Class, Reiner; Schrage, Ramona; Suter-Dick, Laura
Delivering biologics to elicit a therapeutic response in the central nervous system (CNS) remains challenging due to the presence of the blood brain barrier (BBB). Receptor-mediated transcytosis is a strategy to improve brain exposure after systemic drug administration. The availability of a clinically relevant in vitro BBB model is crucial to investigate transcytosis pathways and to predict the penetration of biologics into the CNS. We created a perfused human in vitro BBB model made of induced pluripotent stem cells (iPSC)-derived brain microvascular endothelial cells (BMEC) for studying transferrin receptor-mediated transcytosis. iPSC-derived BMEC were seeded in the top channel of a three-lane microfluidic device (OrganoPlate®). After 2 days in culture, the established cell model exhibited relevant BBB features, including physiological transendothelial electrical resistance in a transwell setting (1500 Ω*cm), reduced apparent permeability (Papp) to the fluorescence tracer Lucifer yellow (20-fold less than cell-free chips), expression of key BBB markers such as tight junctions proteins, transporters, receptors and functional P-gp efflux pump. Moreover, the model exhibited functional transferrin receptor-mediated uptake and transcytosis. To assess selective transferrin receptor-mediated transcytosis, a mixture of anti-human transferrin receptor (MEM-189) and control (sheep IgG anti-bovine serum albumin) antibodies was perfused in the top channel for 2 h. The Papp of MEM-189 was 11-fold higher than that of the control antibody, demonstrating facilitated receptor-mediated transcytosis. Compared to published work reporting a 2-fold ratio, this result is remarkable and establishes the suitability of our model for exploring receptor-mediated transcytosis and screening of antibodies for putative brain shuttle application. A perfused in vitro human model made of iPSC-derived BMEC with the chief characteristics (barrier tightness, functionality) of the human BBB can be applied to study transferrin receptor (TfR)-mediated transcytosis of therapeutic antibodies. This may bring critical advances in drug shuttle technology. Graphical abstract generated with biorender.com.
01A - Beitrag in wissenschaftlicher Zeitschrift
Aerosol and trace gas vehicle emission factors measured in a tunnel using an Aerosol Mass Spectrometer and other on-line instrumentation
(Elsevier, 04/2011) Chirico, Roberto; Prevot, Andre S.H.; DeCarlo, Peter F.; Heringa, Maarten F.; Richter, Rene; Weingartner, Ernest; Baltensperger, Urs
In this study we present measurements of gas and aerosol phase composition for a mixed vehicle fleet in the Gubrist tunnel (Switzerland) in June 2008. PM1 composition measurements were made with a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (AMS) and a Multi Angle Absorption Photometer (MAAP). Gas-phase measurements of CO, CO2, NOx and total hydrocarbons (THC) were performed with standard instrumentation. Weekdays had a characteristic diurnal pattern with 2 peaks in concentrations for all traffic related species corresponding to high vehicle density (∼300 ± 30 vehicles per 5 min) in the morning rush hour between 06:00 and 09:00 and in the afternoon rush hours from approximately 15:30 to 18:30. The emission factors (EF) of OA were heavily influenced by the OA mass loading. To exclude this partitioning effect, only organic aerosol mass concentrations from 60 μg m−3 to 90 μg m−3 were considered and for these conditions the EF(OA) value for HDV was 33.7 ± 2.3 mg km−1 for a temperature inside the tunnel of 20–25 °C. This value is not directly applicable to ambient conditions because it is derived from OA mass concentrations that are roughly a factor of 10 higher than typical ambient concentrations. An even higher EF(OA)HDV value of 47.4 ± 1.6 mg km−1 was obtained when the linear fit was applied to all data points including OA concentrations up to 120 μg m−3. Similar to the increasing EF, the OA/BC ratio in the tunnel was also affected by the organic loading and it increased by a factor of ∼3 over the OA range 10–120 μg m−3. This means that also the OA emission factors at ambient concentrations of around 5–10 μg m−3 would be 2–3 times lower than the emission factor given above. For OA concentrations lower than 40 μg m−3 the OA/BC mass ratio was below 1, while at an OA concentration of 100–120 μg m−3 the OA/BC ratio was ∼1.5. The AMS mass spectra (MS) acquired in the tunnel were highly correlated with the primary organic aerosol (POA) MS from a EURO 3 diesel vehicle with a speed similar to the average tunnel speed.
01A - Beitrag in wissenschaftlicher Zeitschrift
Aerosol climatology and planetary boundary influence at the Jungfraujoch analyzed by synoptic weather types
(Copernicus, 23.06.2011) Collaud Coen, Martine; Weingartner, Ernest; Furger, Markus; Nyeki, Stephan; Prévôt, André S. H.; Steinbacher, Matjaz; Baltensperger, Urs
Fourteen years of meteorological parameters, aerosol variables (absorption and scattering coef-ficients, aerosol number concentration) and trace gases (CO, NOx, SO2) measured at the Jungfraujoch (JFJ, 3580 m a.s.l.) have been analyzed as a function of different synoptic weather types. The Schüepp synoptic weather type of the Alps (SYNALP) classification from the Alpine Weather Statistics (AWS) was used to define the synoptic meteorology over the whole Swiss region. The seasonal contribution of each synoptic weather type to the aerosol concentration was deduced from the aerosol annual cycles while the planetary boundary layer (PBL) influence was estimated by means of the diurnal cycles. Since aerosols are scavenged by precipitation, the diurnal cycle of the CO concentration was also used to identify polluted air masses. SO2 and NOx concentrations were used as precursor tracers for new particle formation and growth, respectively. The aerosol optical parameters and number concentration show elevated loadings during advective weather types during the December–March period and for the convective anti-cyclonic and convective indifferent weather types during the April–September period. This study confirms the consensus view that the JFJ is mainly influenced by the free troposphere during winter and by injection of air parcels from the PBL during summer. A more detailed picture is, however, drawn where the JFJ is completely influenced by free tropospheric air masses in win-ter during advective weather types and largely influenced by the PBL also during the night in summer during the subsidence weather type. Between these two extreme situations, the PBL influence at the JFJ depends on both the time of year and the synoptic weather type. The frac-tion of PBL air transported to the JFJ was estimated by the relative increase of the specific hu-midity and CO.
01A - Beitrag in wissenschaftlicher Zeitschrift
An integrative model for phytochrome B mediated photomorphogenesis. From protein dynamics to physiology
(Public Library of Science, 19.05.2010) Rausenberger, Julia; Hussong, Andrea; Kircher, Stefan; Kirchenbauer, Daniel; Timmer, Jens; Nagy, Ferenc; Schäfer, Eberhard; Fleck, Christian; Harmon, Frank
Plants have evolved various sophisticated mechanisms to respond and adapt to changes of abiotic factors in their natural environment. Light is one of the most important abiotic environmental factors and it regulates plant growth and development throughout their entire life cycle. To monitor the intensity and spectral composition of the ambient light environment, plants have evolved multiple photoreceptors, including the red/far-red light-sensing phytochromes.
01A - Beitrag in wissenschaftlicher Zeitschrift
Ausstellung Programm EduNaT
(Fachhochschule Nordwestschweiz FHNW, 02/2018) Stübi, Claudia; Jäggi, Benedikt; Kern, Yves; Studer, Jan; Som, Kajetan; Stübi, Claudia
Die Ausstellung wurde im Rahmen der Abschlussarbeiten des Programms EduNaT - Education Natural Science and Technology realisiert. Im Programm kooperierten zwischen 2015 und 2017 sechs Hochschulen der Fachhochschule Nordwestschweiz FHNW. Sie setzten gemeinsam 18 Projekte um, mit dem Ziel, die naturwissenschaftlich-technische Bildung aufzuwerten, Erkenntnisse zu gewinnen und diesbezüglich eine verstärkte interdisziplinäre Zusammenarbeit an der FHNW zu etablieren. Die Ausstellung umfasst Text-, Bild- und Videomaterial, Experimentieranlagen und interaktive Elemente.
13 - Ausstellung
Beiträge zum lagerlosen Elektromotor
(Eidgenössische Technische Hochschule Zürich (ETH), 1990) Bichsel, Jürg
Elektromagnetische Lagerung eines Elektromotors durch Integration der Lagerstelle in den Motor durch Kombination des drehmoment- und kraftbildenden Teils an derselben örtlichen Stelle des Elektromotors
11 - Studentische Arbeit
Bestimmung von Zersetzungskinetiken aus dynamischen Thermogrammen mittels eines Convolutional Neural Networks
(Hochschule für Life Sciences FHNW, 2023) Mensing, Dario; Zogg, Andreas; F. Hoffmann - La Roche
Um selbstreaktive Substanzen transportieren zu können muss eine sichere Transporttemperatur bestimmt werden. Als kritische Substanzen gelten Chemikalien mit einer Transporttemperatur unter 75 °C [1]. Die bestehenden Testmethoden (UN Test H.4) zur Ermittlung dieser Temperatur bringen lange Versuchszeiten mit sich und sind riskant da sie grosse Mengen an Testsubstanzen verwenden. Daher ist es wichtig, die Tests auf die kritischen Stoffe zu beschränken [2]. Ein entsprechender Workflow wurde von K. Wegmann während seiner Masterarbeit entwickelt. Die Schwierigkeit bei der Verarbeitung von DSC- und ARC-Daten liegt darin, dass die auftretenden Reaktionsmechanismen unbekannt sind. Entsprechend ist man bei Simulation auf ein einfache Reaktionsmodelle 0ter und nter Ordnung sowie modellfreie Kinetik beschränkt. [2]. In dieser Bachelorarbeit wurde daher eine Methode mittels eines Convolutional Neural Networks (CNN) entwickelt, um unterschiedliche Reaktionsmodelle von Zersetzungsreaktionen anhand von künstlich generierten DSC-Thermogrammen zu bestimmen. Bei einem CNN handelt es sich dabei um ein künstliches neurales Netzwerk, welches ursprünglich dazu entwickelt wurde komplexe Merkmale und Muster in Bildern zu erkennen [3].
11 - Studentische Arbeit
Beurteilung in den neuen Lehrmitteln
(28.11.2017) Metzger, Susanne
06 - Präsentation
Carbon capture from flue gas of a chemical industrial park
(Hochschule für Life Sciences FHNW, 2023) Furrer, Thierry; Zogg, Andreas; Getec
In the chemical park Schweizerhalle, multiple incineration plants handle the hazardous waste generated by production processes. The ALV1 is the smaller one of the two waste solvent incinerators. Within the scope of this project, the feasibility to upgrade this plant with a carbon capture unit was assessed.
11 - Studentische Arbeit
Coated soot particles with tunable, well-controlled properties generated in the laboratory with a miniCAST BC and a micro smog chamber
(Elsevier, 28.05.2021) Ess, Michaela N.; Bertò, Michele; Keller, Alejandro; Gysel, Martin; Vasilatou, Konstantina
A Micro Smog Chamber (MSC) was coupled for the first time with a miniCAST 5201 Type BC combustion generator with the aim to produce a series of stable and reproducible model aerosols simulating the physical properties of combustion particles present in ambient air. With this setup it was possible to generate particles ranging from “fresh” soot (single scattering albedo SSA≤0.05, absorption Ångström exponent AAE close to 1, high EC/TC mass fraction (approximately 90%) and mobility diameter typically <100 nm) to “aged” soot with different amounts of organic coating. The “aged” soot particles could grow up to 200 nm and exhibited high SSA (up to 0.7 at λ = 870 nm), an increased AAE (up to 1.7) and low EC/TC mass fraction (down to <10%). The ageing was achieved by coating the soot particles with increasing amounts of secondary organic matter (SOM) formed by the photo-oxidation of α-pinene or mesitylene in the MSC. Thereby, the SSA and AAE increased with coating thickness, while the EC/TC mass fraction decreased. Over the experimental period of 2 h, the generation of the “aged” soot aerosols was stable with a standard deviation in particle size and number concentration of <1% and <6%, respectively. The day-to-day reproducibility was also satisfactory: with α-pinene as SOM precursor the variability (standard deviation) in particle size was <2% and in the AAE and SSA < 6%. Particle number concentrations up to 106 cm−3 and mass concentrations up to 15 mg/m3 (depending on particle size and SOM amount) could be generated, much higher than what has been reported with other oxidation flow reactors. The generated carbonaceous aerosols could find useful applications in the field of aerosol instrument calibration, particularly in the standardization of filter-based absorption photometers under controlled conditions.
01A - Beitrag in wissenschaftlicher Zeitschrift
Concept Cartoons als diskursiv-reflexive Szenarien zur Aktivierung des Methodenwissens beim Forschenden Lernen
(2016) Arnold, Julia; Kremer, Kerstin; Mayer, Jürgen
01A - Beitrag in wissenschaftlicher Zeitschrift
Continuous in situ lactic acid extraction from sweet whey fermentation broth using a tubular membrane contactor
(2022) Demmelmayer, Paul; Pérez, Alan; Riedl, Wolfgang; Kienberger, Marlene
Background Whey, as the major dairy by-product, has become a severe problem for the dairy industry because its demand has decreased, while its production has increased in the past years. Since the high demand for dairy products tends to further increase, suitable routes for whey valorization are required. Whey contains valuables like lactate, but due its composition matrix, processing is challenging. The high sugar content in whey makes it a potential feedstock to produce lactic acid (LA) via microbial fermentation. Still, the known drawbacks of biotechnological LA production, such as growth inhibition by the product, the use of neutralizers, low productivity, and high overall costs of the process must be overcome. In situ LA recovering using a suitable separation technology is a potential strategy to overcome the mentioned drawbacks. In this work, the in situ LA extraction from a whey fermentation broth was evaluated. Sweet whey was used as feedstock for lactic acid production via microbial fermentation, while LA was recovered by reactive liquid-liquid extraction using a tubular membrane contactor. Method The feed material used in this work is a fermentation broth from sweet whey, which was filtered prior to extraction experiments using microfiltration. In a first series of experiments, two-phase extraction experiments were conducted in temperature controlled separation funnels, to investigate different solvent phase combinations for the lactic acid extraction. Special attention was paid to replace commonly applied fossil-based solvents with green alternatives, such as deep eutectic solvents (DES). After extraction, the extract was treated in a back-extraction step to recover LA from the solvent phase. Here, an anti-solvent, e.g. heptane or p-cymene, was used to transfer LA to the receiving phase, which was water. Afterwards the performance of reactive liquid-liquid extraction of LA using a PTFE membrane contactor was evaluated by using two potential solvent phases, namely tri-n-octyl amine (TOA) with n-decanol and a DES formed from thymol and menthol. From the experimental results the overall mass transfer coefficient was calculated based on a rigorous mass transfer model to predict the LA concentration in both phases. Finally, performance of the in situ LA recovery from sweet whey by using membrane contactor was investigated from both, experimentally and theoretically points of view. Results & Conclusion In the two-phase extraction experiments, the reactive extractants Aliquat336, TOA, trioctylphosphinoxid (TOPO), and the mixture Aliquat336/TOA were found to be most efficient with the diluents 1-decanol, limonene, and a deep eutectic solvent consisting of thymol and menthol. Especially, the DES and limonene are promising as they can be produced from renewable resources. With respect to back-extraction, heptane and p-cymene showed the highest efficiencies for transferring lactic acid into the receiving phase water. In the next step, the selected solvents were used to perform LA recovery in the tubular membrane contactor from a model aqueous solution of LA and a fermentation broth of sweet whey. The proposed technology for valorizing dairy waste through LA biotechnological production shows the feasibility to scaling it up.
06 - Präsentation
Corrigendum to “Powder cohesion and energy to break an avalanche. Can we address surface heterogeneity?” [Int. J. Pharm. 626 (2022) 122198]
(Elsevier, 2023) Brokešová, Jana; Niederquell, Andreas; Kuentz, Martin; Zámostný, Petr; Vraníková, Barbora; Šklubalová, Zdenka
01A - Beitrag in wissenschaftlicher Zeitschrift
Deformationsmessungen im Bergsturzgebiet von Schwanden bei Brienz - Ein Ausbildungsprojekt im Wandel der technischen und methodischen Entwicklung
(SIGImedia, 05/2015) Mahler, Peter
Im Gebiet Schwanderbärgli oberhalb der Gemeinde Schwanden bei Brienz befindet sich ein aktives Bergsturzgebiet. Studierende der Fachhochschule Nordwestschweiz planen, messen und werten dort seit Jahren im Rahmen eines Ausbildungsprojektes dieses Deformationsnetz aus. Zum Einsatz kommen dabei die auf dem Markt modernsten Technologien und Methoden im Bereich der geodätischen Instrumentenfamilien (Satellitenmesssysteme, Präzisions-Tachymetrie, Präzisions-Nivellement, Laserscanner). Die Resultate zeigen die erreichbaren Genauigkeiten und das Langzeitverhalten dieses imposanten Rutschgebiets. Die Möglichkeiten und Veränderungen in der Welt der Geomatik, verursacht durch den technologischen und methodischen Wandel – sowohl in der Vergangenheit, der Gegenwart, als auch in der Zukunft – werden aufgezeigt.
01B - Beitrag in Magazin oder Zeitung
Design of a biocatalytic flow reactor based on hierarchically structured monolithic silica for producing galactooligosaccharides (GOSs)
(Schweizerische Chemische Gesellschaft, 2023) Dejoma, Riccardo; Buscemi, Andrea; Cutrona, Emilio; Shahgaldian, Patrick
Climate change mitigation requires the development of greener chemical processes. In this context, biocatalysis is a pivotal key enabling technology. The advantages of biocatalysis include lower energy consumption levels, reduced hazardous waste production and safer processes. The possibility to carry out biocatalytic reactions under flow conditions provides the additional advantage to retain the biocatalyst and to reduce costly downstream processes. Herein, we report a method to produce galactooligosaccharides (GOSs) from a largely available feedstock (i.e. lactose from dairy production) using a flow reactor based on hierarchically structured monolithic silica. This reactor allows for fast and efficient biotransformation reaction in flow conditions.
01A - Beitrag in wissenschaftlicher Zeitschrift