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3D bioprinting of cartilage tissue: Current advances and challenges in tissue engineering
No full textAs industrial technologies develop, some techniques were adopted and applied in medical fields for treatment improvement. Among them, 3D bioprinting is regarded as a rising and trending technology in the tissue engineering area. This is because not only does it offer patients customized organs or tissues, but also it can lower animal test dependency on drug testing. This paper is mainly focused on the use of 3D printing as a cartilage tissue fabrication for transplantation. In the beginning, general information and background knowledge concerning cartilage and bioprinting approaches were addressed. Subsequently, current research results from eight research teams related to cartilage tissue printing and grafting were introduced. Then the reports were classified and sorted into several groups to analyze and evaluate various methods' properties, advantages, and disadvantages. After that, some classic and traditional ways to produce artificial tissues without 3D bioprinting techniques were described to prove the strength of the novel tissue engineering technology. In the end, several side points, such as limitations, 3D bioprinting usages in fields other than tissue transplantation, market value, and outlook of bioprinting, were discussed. Information and sources were retrieved using Google and PubMed database search engines under specific inclusion and exclusion criteria through a PCC concept. Although the 3D bioprinting technique is still in development processes, it has a high potential to be a game-changing approach in the medical and pharmaceutical fields after commercialization in the future
Öffentlich-rechtliche Verträge – Juristische Grundlagen, Sinn, Fallbeispiele
No full textDer öffentlich-rechtliche Vertrag (örV) stellt eine Handlungsform des deutschen öffentlichen Rechts dar. Es handelt sich um einen Vertrag über einen öffentlich-rechtlichen Gegenstand, an dem sich mindestens eine juristische Person des öffentlichen Rechts beteiligt. Neben dem Verwaltungsakt stellt er die wichtigste Form des Verwaltungshandelns dar. In diesem Papier werden Grundlagen, Sinn und Anwendung erläutert
Experimental and Simulative Study on the Performance of PEM Fuel Cell under Different Operating Conditions
No full textThe aim of the thesis is to study the influence of operating conditions on the performance of the proton exchange membrane fuel cell (PEMFC) such as temperature, cathode stoichiometry and cathode relative humidity. The experiment is conducted at temperature points of 60°C, 70°C and 80°C, where at each temperature point cathode stoichiometry of 2 and 5 are set. Within each stoichiometry, the cell is operated at cathode relative humidity of 50%, 75% and 100%. The fuel cell performance is analyzed using two methods, current-voltage measurement, and the electrochemical impedance spectroscopy, where the polarization curves, power output density and high-frequency resistance (HFR) are recorded. A numerical analysis is then conducted on a 3-dimensional straight single channel fuel cell and is fitted with the data measured experimentally.
Increasing the temperature has a different degree of improvement on the fuel cell’s performance based on its cathode stoichiometry and relative humidity settings. The HFR measurements provide an insight into the voltage loss that is exerted by the fuel cell on each test condition. The numerical analysis shows that the impact of operating conditions does not exhibit any significant differences on the fuel cell model
The effects of P53 stabilitization in SMARCB1-deficent, deficent TP53- wildtype epitheliod sarcoma cells
No full textEpithelioid sarcomas (ES) which are a rare form of soft tissue sarcomas are known to afflict both males and females with a slight bias for males. They are characterised by a defective SMARCB1 gene as well as a TP53 wildtype. Owing to this distinctive trait, it was hypothesised that reactivating p53 protein could hold therapeutic advantage in these type of tumours since p53 is a transcription factor at the crossroads between cell survival or death. P53 downstream target genes regulate the cell cycle or promote apoptosis. Since p53 is inactivated by its natural inhibitor, MDM2, in these types of tumours (Claudia Schaffner et al. 1999), using an MDM2 inhibitor to disrupt the P53-MDM2 interaction and stabilise p53 offered a sensible rationale to explore. It is often the case that cancer cells develop a resistance to a particular chemotherapy
over time. Therefore, using a combination of two different inhibitors with completely different mechanisms of action to antagonise the tumour cells and prevent a possible recurrence was also considered.
Two epithelioid sarcoma cell lines, VAESBJ and EPI544, were used for these experiments. HDM201, which is an MDM2 inhibitor, and doxorubicin, the current standard in threating epithelioid sarcomas, were both employed to be used as single agent treatments and in combination. Firstly, it had to be established that both cells are sensitive to the inhibitors in a dose dependent fashion. This was done using the MTS assay which quantifies cell viability based on the metabolism of tetrazolium salts and its eventual conversion to a purple soluble formazan residue by viable cells. Next, to further investigate the downstream effects of reactivated p53 in the cell populations, indirect immunofluorescence (IF) was performed to demonstrate that both inhibitors were capable of individually stabilising p53 in both cell lines.
To further support the results from the indirect IF, western blot analysis was done to prove that p53 accumulates within the cell. Furthermore, quantitative polymerase chain reaction (PCR) was also
performed to explore the extent to which p53’s stabilisation influences the fate of the treated cells.
The results obtained from the MTS assay experiments showed that the cell lines used were indeed sensitive to both inhibitors as single agent treatments (EPI544 cells IC50 (HDM)= 0.212nM, IC50 (Dox)=
259.9nM) and VAESBJ IC50 (HDM)= 1.52µM, IC50 (Dox)= 17.5nM). At their respective IC50 values in combination, both drugs acted synergistically to halt cell viability in VAESBJ cell line whereas they were antagonistic against EPI544 cell line. However, these discrepancies were due to the dose response of the cells to the drugs. Moreover, from the IF analysis, p53 was clearly stabilised and as a result affected cell viability in all cell lines for both drugs. There was a considerable amount of p53 accumulation in treated cells when analysed by western blot. Lastly, the qPCR data showed that upon stabilisation, p53 upregulated the cell cycle checkpoint protein p21 as well as its natural regulator MDM2 because of a negative feedback loop meant to regulate the amount of p53 in normal cells. BCL2 which encodes an anti-apoptotic protein is also downregulated in all treated cells. Pro-apoptotic TP53I3 gene is significantly upregulated in the cell populations treated with the combination.
In a nutshell, the results support the rationale that targeting MDM2 in ES tumours holds therapeutic value.
They also highlight the usefulness of combination therapies as a better approach at targeting cancer cells.
Although p53 is stabilised, its accumulation and downstream effects are largely dependent on whether it was achieved through posttranslational modifications or not. These results necessitate future research to characterise the effects of a combination of HDM201 and Doxorubicin on ES tumours in vivo
Die Erforschung von potenziellen Zusammenhängen zwischen sozialer Neugier und der Größe der sozialen Netzwerke von Studierenden zu Beginn des Studiums
No full textAufbau und Erhalt von sozialen Beziehungen finden über das gesamte Leben hinweg statt. In manchen Lebensphasen werden vermehrt soziale Kontakte geknüpft. Ein solcher Abschnitt ist oft der Beginn eines Studiums. Hier vergrößert sich in der Regel das soziale Netzwerk. Wie viele neue Beziehungen aufgenommen werden, wird unter anderem von der Persönlichkeit der jeweiligen Person bestimmt. Um den Einfluss von sozialer Neugier auf die Größe von sozialen Netzwerken zu überprüfen, wurden die Daten der Network Evaluation for Academic Retention - Studie ausgewertet. Die Studie erhebt unter anderem Daten zur Persönlichkeit und über egozentrierte Netzwerke von Erstsemesterstudierenden. Die Befragung erfolgt über einen Zeitraum von sechs Monaten zu drei konkreten Messzeitpunkten. Der Einfluss von sozialer Neugier auf die Größe des gesamten sozialen Netzwerks und des nicht-familiären Netzwerks wurde mithilfe von multiplen Regressionsanalysen untersucht (N = 93). Es konnte kein signifikanter Zusammenhang gefunden werden. Auch die Analyse des Effekts der sozialen Neugier auf die Veränderung der Netzwerkgröße über sechs Monate ergab keine signifikanten Ergebnisse (n = 55). Bei den Analysen wurden auch andere Persönlichkeitsvariablen betrachtet, die in der Forschung bereits signifikante Zusammenhänge mit der Größe von sozialen Netzwerken aufgewiesen haben. In der verwendeten Stichprobe konnten diese Zusammenhänge nicht verifiziert werden. Die Gründe für diesen Unterschied werden diskutiert. Die Untersuchung bietet einen ersten Einblick in den Zusammenhang von sozialer Neugier und der Größe von sozialen Netzwerken, welcher in der Zukunft weiter erforscht werden sollte.The building and preservation of relationships takes place throughout one’s whole life. During some life stages socialization happens more frequently than in others. One of those times is the start of academic studies, where the size of the social network usually increases. Among other things the personality of the respective person has influence on the number of relationships that are newly integrated. To examine the influence of social curiosity on the size of social networks, data from the study “Network Evaluation for Academic Retention“ has been used. It includes amongst others the data of personality traits and egocentric networks of first-year students and resulted from three surveys over a period of six months. The impact of social curiosity on the size of the entire and of the non-familial social network has been examined by means of multiple regression analysis (N = 93). No significant connection could be found. The same applies for the impact of social curiosity on the change of network size after six months (n = 55). There was also no significant result. The analysis includes other variables regarding the personality, as well, which have been proven to have an impact on the size of social networks by applied research already. Those known connections could not be found in the used sample. Reasons for that discrepancy will be discussed. This study offers a first impression of the correlation between social curiosity and the size of social networks and this topic should be examined further in future
Multi Languages Fake News Detection
No full textNews is one type of information that has the potential to influence a large number of people. People have received news since the beginning of time through various birds, short letters, and other means. When newspapers were invented, information was available everywhere on paper. The news is no longer limited to paper-based platforms, thanks to the digitalization of online platforms. The online news platform is now available to read the news in a matter of seconds. As a result, news can easily connect people, and it is being used to spread fake news. Fake news is spread to gain attention for the wrong reasons. Different languages are used in our world to express our thoughts and feelings. There are specific materials for each language. The English language is the most studied topic when it comes to identifying fake news. Data and research resources are few in other languages, hence there is little research done. Of these, Bengali is one of the most widely spoken. Our ultimate goal is to create a tree that contains elements of both English and Bengali. Research on fake news and web scraping was used to get the language news data. Multilingual transformer models m-BERT and xlm-ROBERTa with long text or tokens are used to detect fake news (512 tokens or any token size). The two models were compared using two different datasets (with stop words and the other without) using three different fine-tuning freeze approaches (Freeze, No Freeze, and Freeze Embed). The results show that the dataset with stop words had a somewhat better performance than the dataset omitting stop words. The xlm-RoBERTa model outperforms the m-BERT model in terms of F1-score and accuracy
Sample Collection Method for a Dispenser-Integrated Germ Detection System in the field of Hand Hygiene
No full textThis bachelor thesis validates a demonstrator that had a sample collection method for a dispenser-integrated germ detection system in the field of hand hygiene. In addition, the temperature of the hand was analysed; this was taken from previous work by T.Mooren. The first task was to validate a different spray nozzle. Eight nozzles were analysed by their spray patterns and ranked. Further experiments were carried out with the highest ranked spray nozzle.
Subsequently, an attempt was made to prove whether bacteria could be washed off. This was done with an experimental setup to simulate washing off the palm of the hand, realised in the frame scope of this work. Calibrated glass slides with and without bacteria were used to enable localisation of the same bacterial areas before and after.
Afterwards, this procedure was expanded to analyse the behaviour of soap and foam bacteria. The drip tray was changed to obtain a high number of bacteria into the sensing device. An excellent visual representation had to be achieved, so a mini-microscope was used in the demonstrator. This mini-microscope was able to capture
and display images of the washed-off bacteria sample generation visually. Different lenses and that securitisation versions were tested for the microscope. Within this, the resolution of the pixels could be improved. Also, the comparison between two
different objectives were evaluated.
A complete electronic system was then integrated into a disinfection dispenser. This included a Raspberry-Pi and microcontroller for programming and controlling the system. Other components were the mini-microscope, a pump, LED-strips, two-infrared sensors for temperature measurements and an LCD-screen for visualisation.
Finally, a fully functional system was presented to the funding agency the VDI/VDE-IT and to the employees of Ophardt Hygiene AG. The system was able to wash bacterial samples from a hand or a slide and display them visually with a microscope; the temperature of the hand was taken too. This 1st demonstrator of the project will be set up soon for Ophardt Hygiene AG employees to test at the building entrance in order to valuate long-term stability and user-friendliness. Data for the further project phases will be collected and determined there
Chancen und Risiken einer CRISPR/Cas9 basierten Gentherapie an Duchenne Muskel Dystrophie und Zystischer Fibrose
No full textHintergrund: Seit 2013 gewinnt das autonome Immunsystem der Bakterien CRISPR/Cas9 an Bedeutung für die Humanmedizin. Das System kann einen präzisen Schnitt in der DNA verursachen, gegebenenfalls neue Gene einsetzen. Mit CRISPR/Cas9 könnten krankheitsverursachende Gene potenziell ausgeschaltet und eine phänotypische Verbesserung oder Heilung ermöglicht werden. Jedoch gibt es noch Herausforderungen, welche die Behandlungsmöglichkeiten in der konventionellen Humanmedizin limitieren. Ziel der Arbeit: Ziel dieser Arbeit ist eine Abhandlung über die Chancen, Risiken und Herausforderungen der Genschere CRISPR/Cas9 in der Humanmedizin an genetisch bedingten Erkrankungen am Beispiel von Duchenne Muskel Dystrophie und Zystischer Fibrose.
Ergebnisse: CRISPR/Cas9 kann an CF humanisierten Säugetiermodellen, sowie IPS Stammzellen eine Korrektur der F508 Deletion im CFTR Gen verursachen. Die Forskolin Schwellung ist nach Behandlung mit CRIPSR/Cas9 im Säugetiermodell wiederhergestellt. Es trat ein Off-Target Effekt auf. Gleichwohl konnte eine Behandlung mit CRISPR/Cas9 am humanisierten Säugetiermodell für DMD die Dystrophin-Expression wiederherstellen. Muskelkraft in Skelett- und Herzmuskulatur hat sich signifikant verbessert. Es kam zu On-Target Effekten und Immunreaktionen.
Fazit: CRISPR/Cas9 hat das Potenzial genetische Mutationen zu korrigieren und die Gen-Expression zu retten. Weitere Studien müssen unternommen werden, um das Risiko von Off-Target Effekten zu minimieren, Langzeitwirkungen zu beobachten und Drug Delivery zu optimieren
Using MS Excel as solver in ansys workbench for the static and fatigue assessment in accordance with the FKM guideline
No full textThe FKM guideline offers a structured and detailed framework for static and fatigue strength assessment for steel, aluminum, and cast iron components. This study aimed to investigate Microsoft Office Excel’s use of mechanical components’ static and fatigue strength verification for non-welded and welded components and its integration into Ansys Workbench. An FKM Excel tool was developed to calculate the assessment and tested against the FKM guideline example. A detailed comparison is made between the results of the FKM Excel tool and the FKM guideline example. Moreover, relevant stress and stress gradient values were obtained using Ansys Parametric Design Language (APDL). This investigation has revealed that the methodology is very efficient and faster. Furthermore, it makes it possible to use for proof strength. This research implies that there is a possibility of obtaining further automating processes in excel and Ansys Workbench
A Hybrid Strategy Using Human Centered Design and Agile Methodologies to Develop an Error Taxonomy to Assist Businesses in Avoiding and Repairing Software Issues
No full textCompanies often utilize error taxonomies to handle software problems. Agile and scrum-based software engineering procedures leverage software testing and quality management to find, repair, and prevent functional faults. Taxonomies help programmers see patterns and solve comparable challenges. Usability engineering-based taxonomies emphasize the use of HCD approaches to discover and classify usability concerns across the software development life cycle. Software and usability engineering have pros and cons. This thesis presents a hybrid software challenge taxonomy to bridge these two areas. The research project aims to build a new hybrid error classification system for identifying and correcting software errors at their source, leading to more user-centric software. Software engineering taxonomies and design issues are investigated. The weaknesses of any research taxonomy are then evaluated against one that fits some of this thesis' needs. User interviews and contextual inquiry are used to uncover software faults. The results of the study showed that poor usability, a mediocre user interface, workflow issues, and poor user experience caused most non-technical problems. Non-functional faults may have created many technical challenges. Six out of ten company professionals who participated in a questionnaire and interview mistook "usability" for "user experience." Usability and user experience were valued by two out of ten specialists, but they were misunderstood, expensive, and time-consuming premium approaches, and thus not included in the software development lifecycle. Ignoring non-functional issues may have caused numerous software failures. Scrum and agile used alone may also be to blame for many of the software issues uncovered in this thesis project