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The critical process parameters cell density and viability during mammalian cell cultivation are assessed by UV/VIS spectroscopy in combination with multivariate data analytical methods. This direct optical detection technique uses a commercial optical probe to acquire spectra in a label-free way without signal enhancement. For the cultivation, an inverse cultivation protocol is applied, which simulates the exponential growth phase by exponentially replacing cells and metabolites of a growing Chinese hamster ovary cell batch with fresh medium. For the simulation of the death phase, a batch of growing cells is progressively replaced by a batch with completely starved cells. Thus, the most important parts of an industrial batch cultivation are easily imitated. The cell viability was determined by the well-established method partial least squares regression (PLS). To further improve process knowledge, the viability has been determined from the spectra based on a multivariate curve resolution (MCR) model. With this approach, the progress of the cultivations can be continuously monitored solely based on an UV/VIS sensor. Thus, the monitoring of critical process parameters is possible inline within a mammalian cell cultivation process, especially the viable cell density. In addition, the beginning of cell death can be detected by this method which allows us to determine the cell viability with acceptable error. The combination of inline UV/VIS spectroscopy with multivariate curve resolution generates additional process knowledge complementary to PLS and is considered a suitable process analytical tool for monitoring industrial cultivation processes.
Heat pumps in combination with a photovoltaic system are a very promising option for the transformation of the energy system. By using such a system for coupling the electricity and heat sectors, buildings can be heated sustainably and with low greenhouse gas emissions. This paper reveals a method for dimensioning a suitable system of heat pump and photovoltaics (PV) for residential buildings in order to achieve a high level of (photovoltaic) PV self-consumption. This is accomplished by utilizing a thermal energy storage (TES) for shifting the operation of the heat pump to times of high PV power production by an intelligent control algorithm, which yields a high portion of PV power directly utilized by the heat pump. In order to cover the existing set of building infrastructure, 4 reference buildings with different years of construction are introduced for both single- and multi-family residential buildings. By this means, older buildings with radiator heating as well as new buildings with floor heating systems are included. The simulations for evaluating the performance of a heat pump/PV system controlled by the novel algorithm for each type of building were carried out in MATLAB-Simulink® 2017a. The results show that 25.3% up to 41.0% of the buildings’ electricity consumption including the heat pump can be covered directly from the PV installation per year. Evidently, the characteristics of the heating system significantly influence the results: new buildings with floor heating and low supply temperatures yield a higher level of PV self-consumption due to a higher efficiency of the heat pump compared to buildings with radiator heating and higher supply temperatures. In addition, the effect of adding a battery to the system was studied for two building types. It will be shown that the degree of PV self-consumption increases in case a battery is present. However, due to the high investment costs of batteries, they do not pay off within a reasonable period.
Die klassischen Vertriebsaufgaben verändern sich intensiv und schnell. Vertriebsmanager benötigen dringend neue strategische Ansätze, wie sie künftig Kundenkontakte gestalten, Distributionskanäle steuern und effektiver verkaufen können. Eine aktuelle Studie gibt Aufschluss, wie sich Unternehmen auf den Strukturwandel einstellen können.
Faszination Flughafen
(2020)
Estimating molar solubility from the Hildebrand-Scott relation employing Hansen solubility parameters (HSP) is widely presumed a valid semi quantitative approach. To test this presumption and to determine quantitatively the inherent accuracy of such a solubility prognosis, l-ascorbic acid (LAA) was treated as an example of a commercially important solute. Analytical calculus and Monte Carlo (MC) simulation were performed for 20 common solvents with total HSP ranging from 14.5 to 33.0 (MPa)0.5 utilizing validated material data. It was found that, due to the uncertainty of the material data used in the calculations, the solubility prediction had a large scattering and, thus, a low precision.
Relationship between a high-performance work system and employee outcomes: a multilevel analysis
(2020)
Although research on high-performance work systems (HPWS) is increasing, there are few studies in which the focus is on whether and how firm-level HPWS affect individual-level employee outcomes. Using social identity theory, we examined the relationship between HPWS and employee outcomes, and the role organizational identification plays as a mediator in this relationship. We used a multilevel research design and collected data at the organizational and individual levels from a sample of 485 employees of 32 companies in Guangdong Province, China. We used Amos 17.0 and hierarchical linear modeling 6.08 software to examine our hypotheses and the theoretical model. Results showed that organizational identification fully mediated the relationship between HPWS and employees’ job performance as well as that between HPWS and their turnover intention. Our findings provide new insights into the relationship between firm-level human resource management and individual-level employee outcomes, and highlight the importance of considering the implementation of HPWS practices to strengthen employees’ identification with the organization and improve their performance.
Aimed at the problem that the accuracy of face image classification in complex environment is not high, a network model F-Net suitable for aesthetic classification of face images is proposed. Based on LeNet-5, the model uses convolutional layers to extract facial image features in complex backgrounds, optimized parameters in the network model, and changes the number of convolutional layers and fully connected layer feature elements in the model. The experimental results show that the F-Net network model proposed in this paper has a face image classifation accuracy of 73% in complex environment background, which is better than other classical convolutional neural network classification models.
Human adipose-derived stem cells (hASCs) have become an important cell source for the use in tissue engineering and other medical applications. Not every biomaterial is suitable for human cell culture and requires surface modifications to enable cell adhesion and proliferation. Our hypothesis is that chemical surface modifications introduced by low-discharge plasma enhance the adhesion and proliferation of hASCs. Polystyrene (PS) surfaces were modified either by ammonia (NH3), carbon dioxide (CO2) or acrylic acid (AAc) plasma. The results show that the initial cell adhesion is significantly higher on all modified surfaces than on unmodified material as evaluated by bright field microscopy, live/dead staining, total DNA amount and scanning electron microscopy. The formation of focal adhesions was well pronounced on the Tissue Culture PS, NH3-, and CO2 plasma modified samples. The number of matured fibrillar adhesions was significantly higher on NH3 plasmamodified surfaces than on all other surfaces. Our study validates the suitability of chemical plasma activation and represents a method to enhance hASCs adhesion and improved cell expansion. All chemical modification promoted hASCs adhesion and can therefore be used for the modification of different scaffold materials whereby NH3-plasma modified surfaces resulted in the best outcome concerning hASCs adhesion and proliferation.
Dieser Beitrag analysiert die Reform der IFRS und US-GAAP-Standards zur Bilanzierung von Leasingverhältnissen. Am Beispiel der McKesson Europe AG werden die Auswirkungen der erstmaligen Anwendung der Standards beim Leasingnehmer veranschaulicht. Von besonderem Interesse ist dabei ein Vergleich der Bilanzierungsmodelle nach den "alten" Standards IAS 17 und ASC 840 bzw. nach den "neuen" Standards IFRS 16 und ASC 842. Im Ergebnis zeigt sich keine vollständige Übereinstimmung von IFRS und US-GAAP. Vor allem beim Ausweis in der Gewinn- und Verlustrechnung ergeben sich Unterschiede, die sich auch auf die Ergebniskennzahlen auswirken.
Size and function of bioartificial tissue models are still limited due to the lack of blood vessels and dynamic perfusion for nutrient supply. In this study, we evaluated the use of cytocompatible methacryl-modified gelatin for the fabrication of a hydrogel-based tube by dip-coating and subsequent photo-initiated cross-linking. The wall thickness of the tubes and the diameter were tuned by the degree of gelatin methacryl-modification and the number of dipping cycles. The dipping temperature of the gelatin solution was adjusted to achieve low viscous fluids of approximately 0.1 Pa s and was different for gelatin derivatives with different modification degrees. A versatile perfusion bioreactor for the supply of surrounding tissue models was developed, which can be adaped to several geometries and sizes of blood-vessel mimicking tubes. The manufactured bendable gelatin tubes were permeable for water and dissolved substances, like Nile Blue and serum albumin. As a proof of concept, human fibroblasts in a three-dimensional collagen tissue model were sucessfully supplied with nutrients via the central gelatin tube under dynamic conditions for 2 days. Moreover, the tubes could be used as scaffolds to build-up a functional and viable endothelial layer. Hence, the presented tools can contribute to solving current challenges in tissue engineering.
