SACM - Germany
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Item Restricted Investigation of the role of Kv1.3 and Kv1.6 potassium channels in retinal ganglion cell degeneration in vitro.(Eberhard-Karls-University Tübingen, 2023-12-11) Fallatah, Azdah Hamed; Paquet-Durand, François1.0. Abstract 1.1. Introduction Organotypic retinal explants are an ideal system for identifying and studying potential treatments for retinal diseases, such as inherited retinal degeneration (IRD). In the organotypic retinal explant culture procedure, retinal ganglion cells (RGCs) usually progressively die in response to optic nerve axotomy. Previous studies connected RGC death to excessive NO/cGMP/PKG signalling. Another study showed that PKG targets Kv1.3 and Kv1.6 potassium channels, which are located in the ganglion cell layer (GCL). Others showed that Kv1.3/Kv1.6 potassium channels contribute to RGC degeneration after optic nerve crush in vivo. Interestingly, recent studies showed that PKG inhibition in retinal explants restored the viability and function of RGCs in vitro. Here, we investigated whether the direct inhibition of Kv1.3 and Kv1.6 channels with 50 nM Margatoxin (MrgX) might rescue RGCs in vitro to find a possible relationship between RGCs survival, PKG inhibition, and Kv1.3/Kv1.6 channels. 1.2. Methods For this study, cultures of organotypic retinal explants derived from post-natal day (P) 12 wild type (WT) mice were treated with the Kv1.3/Kv1.6 inhibitor of MrgX until P13 (24h) or P14 (48h). The PKG inhibitor CN238 was used to treat retinal explants at P13 (24h), P14 (48h), and P24. The rate of RGC degeneration was evaluated using both TUNEL-assay, which can label dead cells, and RNA-binding protein with multiple splicing (RBPMS) staining, which is a marker for RGCs. Furthermore, Amacrine cell (AC) staining was used to determine the protective effect of MrgX and CN238. 1.3. Results RGCs survived in vitro after 48h of culture with MrgX, RBPMS-positive cells showed a 70 % increase per mm2. On the other hand, the number of TUNEL-positive cells remained below 1,000 per mm2 in both MrgX-treated and non-treated groups. The overall percent difference in cell death between the two groups was 2%. In cultures treated with CN238, the amount of TUNEL-positive cell/mm2 dropped significantly after 24h and 48h. Cultures treated with CN238 for 10 days showed a significant increase in RBPMS-positive cells/mm2 and a significant decrease in TUNEL-positive cells/mm2. 1.4. Conclusion The inhibition of the Kv1.3 and Kv1.6 channels with 50 nM MrgX protected RGCs from the induced degeneration due to optic nerve transection in WT retina in vitro. This suggests a relationship between Kv1 channels and RGC death. In addition, the CN238-mediated PKG inhibition rescued RGCs. Together these results suggest that RGC degeneration in retinal explants following the severing of the optic nerve could be triggered by a potential new putative cell death pathway, which involves the signalling along the cGMP/PKG/Kv1 pathway.10 0Item Restricted Orthodontic treatment effect on the oral health-related quality of life, oral function, and facial aesthetics in a group of Swedish adolescents, a longitudinal study(Karolinska Institutet, 2024) Asiri, Elham; Pegelow, MarieBackground: Malocclusion is one of the most prevalent oral conditions that negatively impact patients' physiological and psychological well-being. This longitudinal research aims to investigate how orthodontic treatment affects OHRQoL in a Swedish cohort of adolescents. Material and methods: Sixty-nine patients with different malocclusions who have had orthodontic treatment at Karolinska Institutet, aged 13 to 19, participated in this study. The patients answered OHRQoL questionaries at three different times: Before starting orthodontic treatment, during, and after finishing orthodontic treatment. The questionnaire consisted of three components: Oral Health Impact Profile-14 (OHIP-14), Jaw Functional Limitation Scale-20 (JFLS-20), and Orofacial Aesthetic Scale (OES). The data were statistically analyzed using the R software package. Friedman test assessed if answers differed significantly before, during, and after treatment. Multiple pairwise tests were used to identify which time points were different. Repeated ANOVA of mean was used in sum scores over time. Results: Significant change in mean values of aesthetic sum scores of all malocclusions at three time points; baseline to during (p-value 0.02), during to after (p-value 0.01), and from baseline to after treatment (p-value 0.00). For OHIP-psychosocial impact domain, significant improvement was found when a combination of all groups was tested from baseline to after treatment. For separate questions, the following questions was significantly decreased in time point before to after treatment: OHIP_10: “Been embarrassed”, Est_03: “Your mouth’s appearance (smile, lips, visible teeth)”, Est_04: “Appearance of your rows of teeth”, Est_05: “Shape/form of your teeth”, Est_08: “Overall, how do you feel about your face, mouth, and teeth” (p-value 0.00). Est_06: “Colour of your teeth” (p-value 0.02). Conclusion: Orthodontic treatment has a positive effect on OHRQoL in Swedish adolescents, especially in the aesthetic and psychosocial domain.10 0Item Restricted Setting and Achieving Sustainable Environmental Goals in Ghadah Alsaeedi's Fashion and Cosmetic Business: A Case Study in Saudi Arabia(SRH University of Applied Sciences Berlin, 2024) Alsaeedi, Ghadah; Hessal, FranzAbstract: This study by Ghadah Alsaeedi focuses on sustainable practices in the fashion and cosmetics industries, focusing on Saudi Arabia. Findings indicate that sustainable business practices are practical in Saudi Arabia even against challenges such as complex logistics and low purchaser awareness. Thus, the paper emphasizes that such a sustainable drive can only be possible through continuous innovation and community participation. As much as it is an intelligent economic strategy, the commitment represented in the word 'sustainability' indicates a vision for the future that is ethical, environmental, and social. This research displays how sustainable practices may navigate complex industrial systems and impact future moral and responsible ones - all of which have revolutionary implications, making this an essential inquiry into the potential of sustainable practice. Aside from the valuable perspectives on the unique challenges and triumphs that mark Ghadah Alsaeedi's businesses, the study would also contribute to the discourse on sustainable business methodologies in the fashion and cosmetics industries, most especially taking into consideration the unique cultural and economic milieu of Saudi Arabia3 0Item Restricted Pushing the Boundaries of Photoconductive Sampling in Solids(Ludwig-Maximilians-Universität München, 2023-04) Altwaijry, Najd Abdulaziz; Kling, Matthias F; Fattahi, HaniehThe advent of laser-based optical tools featuring few-cycle pulses with durations of less than a hundred femtoseconds in the late 1980s enabled scientists to initiate and observe the evolution of chemical reactions. This powerful approach combined the interactions of light and matter and unleashed an unprecedented metrology concept that tracks the interactions of atoms and molecules in their natural timescales. Electron wavepacket dynamics take place in the attosecond range, a thousand times faster than molecules. In optical terms, such durations typically last less than the half-cycle duration of optical fields. Consequently, the investigation of such electronic processes necessitates measurement techniques capable of resolving the oscillations of the electric field of light. The primary objective of this thesis is to develop and advance novel field characterisation techniques based on photoconductive sampling. The first portion of this thesis addresses broadband field characterisation based on nonlinear photoconductive sampling. A theoretical analysis of current formation and localisation in solids is presented, prompting the fabrication of a heterostructured sample with the aim of enhancing the magnitude of the signal obtained from the measurement technique. A thorough proof-of-principle experiment is performed, whereby a significant enhancement in signal magnitude is established. As a consequence of signal improvement, the heterostructured sample reaches the desired stability regime earlier than its traditional bulk counterparts. Moreover, the performance of the heterostructured sample for field characterisation is compared to fused silica and benchmarked against the well-established technique of electro-optic sampling. These results pave the way towards field sampling in low pulse energy systems. The following section details broadband field characterisation based on linear photoconductive sampling by employing tailored pulses from a waveform synthesiser. Visible-ultraviolet pulses are utilised to inject carriers in a common semiconductive material (gallium phosphide), enabling the complete characterisation of a mid-infrared test field. Furthermore, the technique is validated against electro-optic sampling. When compared to electro-optic sampling, the response function of linear photoconductive sampling is concerned with the intensity envelope of the gating field, relaxing the strict requisites on the temporal phase of the gate. The demonstrated results represent a significant achievement in extending field sampling techniques beyond 100 THz and towards the visible range. Finally, a machine learning-based algorithm for denoising waveforms obtained from a laboratory setting is developed and implemented. The algorithm is based on a one-dimensional convolutional neural network, ideal for processing data presented on an evenly spaced grid. The model is compared with well-established methodologies, namely denoising via the fast Fourier transform and wavelet analysis and exhibits excellent performance, extending the repertoire of tools typically used for combating noise. The field characterisation methodologies presented in this thesis pave the way towards accessible and cost-effective field sampling techniques, enabling researchers to study field-induced electron dynamics in matter and usher in ultrafast optoelectronic signal processing towards the PHz range. In general, the field characterisation techniques presented occupy a small footprint, and the measurements take place in ambient air conditions, facilitating their integration in existing experimental infrastructures. With the aid of AI-accelerator chips, the machine learning tool developed in this thesis can be implemented during laboratory measurements as a concurrent denoising technique.19 0Item Restricted In Vitro Cytotoxic and Genotoxic Assessment of Nano Polyethylene Terephthalate Exposure on A549 Cells(University of Copenhagen, 2023-05-30) Alzaben, Mohammad; Roursgaard, MartinGlobal plastic production in 2019 amounted to 359 million tons, with the European Union contributing 17%. Plastic has caused environmental and health concerns. Nanoplastics, tiny fragments of plastic measuring less than 1μm in size, have become ubiquitous in the environment. As a result of plastic pollution and poor waste management, nanoplastics have infiltrated several ecosystems, including oceans, freshwater bodies, and even the air we breathe. Studies have linked exposure to MP/NP to adverse health effects such as Pneumoconiosis, chronic bronchitis, allergic and asthmatic reactions, and lung and digestive system cancer, raising concerns about their potential health effects. This study aims to assess two main biological adverse effects of nanoplastics, cytotoxicity and genotoxicity, on human lung carcinoma epithelial cells (A549). We chose polyethylene terephthalate (PET) because it is one of the top-produced plastic polymers. We found that NPET significantly induces ROS production and DNA strand breaks = 0.10 lesions/106 bp at the highest concentration (125 μg/ml).7 0Item Restricted Autoantibodies against red blood cells in malaria- good or bad?(Lund University, 2024-06) Saleh, Bandar; Kristina, Persson; Swedberg, GöteMalaria is a life-threatening disease today occuring mostly in tropical regions and it is transmitted through the bite of female Anopheles mosquitoes. Many species of Plasmodium infect humans where P. falciparum is the most fatal. Red blood cells (RBCs) are the main target where the parasite replicates. A better understanding of how naturally immune individuals control infections could facilitate future vaccine studies. This thesis investigates the ambiguous role of autoantibodies against RBCs in malaria development. We have investigated healthy adults living in a malaria endemic area in Uganda and found that more than half had antibodies against RBCs. Specific antibodies directed against RBC surface antigens, incriminated in merozoite invasion such as glycophorins A, B and C, as well as JMH (SEMA7A), were detected, and potentially these antibodies could be beneficial. Other antibodies had partial specificity against the blood group antigens Rh, Diego, and Cromer. 15% were DAT-positive and 28% were parasite positive (by PCR), and these had higher anti-parasite extract IgG levels and more inhibition in growth/invasion assays, however there was no correlation with presence of antibodies against RBCs. We also measured different inflammatory markers and found some Ugandans to have low haptoglobin levels and more than half had low orosomucoid levels. There was no correlation with PCR-positivity or anti-RBCs or anti-parasite antibodies, and in general there were very few signs of inflammation in spite of presence of parasites. In contrast to the above possibly beneficial autoantibodies, anti-Phosphatidylserine (PS) antibodies have been linked to anemia, a common complication in pregnancy. The levels of anti-PS IgG antibodies were investigated in pregnant Ugandan women. Anti-PS inversely correlated with packed cell volume (PCV) but not with anti-VAR2CSA IgG or parasitemia, indicating a multifactorial modulation. Anti-PS levels were lowest in multigravidae which may explain the better control of anaemia in these individuals. During the first year of life, levels of anti-PS gradually increase and show several correlations with atypical P. falciparum-specific B-cells, implicating that further investigations are needed to conclude the functional aspects of these antibodies and which part they play in development of immunity against malaria. In conclusion, our results showed that specific autoantibodies against RBCs are very common in malaria endemic areas. A clear presence of antibodies against RBCs in parallel with high levels of IgG and almost no signs of inflammation was observed in healthy adults living in such areas, even though many were carrying parasites, indicating that these Ugandan adults have reached a state of immunity where they can harbor parasites without the need for any major inflammatory response. We speculate that antibodies against different RBC surface antigens which are also receptors for merozoite invasion might be beneficial for long term protection, while other antibodies such as those against PS could be more harmful.12 0Item Restricted THE EFFECT OF PORCELAIN THICKNESS IN RELATION TO PREPARATION DEPTH ON FRACTURE STRENGTH OF TRANSLUCENT ZIRCONIA CROWNS(Malmo University, 2016) Bakitian, Fahad; Steyern, Per Vult vonObjective. The purpose of the study was to evaluate the fracture strength of veneered high translucent Y-TZP crowns with the same outer dimensions, but with different porcelain layer thicknesses, with different inner dimensions (preparation depths). Material and methods. Seventy standardized crowns divided into seven groups (n = 10) were fabricated. The crowns in the first six groups were divided according to different thicknesses of the porcelain layer on Y-TZP copings: 0.3 mm, 0.5 mm, 0.8 mm, 1.0 mm, 2.0 mm, and 2.5 mm. The crowns in the seventh group had the same porcelain thickness as group 1 but with preparation depth as group 6. All crowns underwent thermocycling, storing in moist environment and cyclic pre-loading. After fatigue, the crowns underwent to single-load-to-failure test. Results. The crowns with 1.0, 0.8 and 0.5 mm of porcelain layer thicknesses showed no significant differences in fracture strength (1540 N, 1313 N, and 1286 N). Groups 2.5 mm and 2.0 mm showed significantly lower fracture strength (851 N and 910 N) compared to all other groups. There was no statistical difference in fracture strength of crowns with same thickness but with different preparation depths (1136 N and 1202 N). Conclusions. The reduction in porcelain thickness to 0.5 mm does not impair the fracture strength of crowns significantly. Fracture strength of crowns with micro-coating layer of porcelain (0.3 mm) might be lower, but still in range of what is considered to be clinically sufficient. Preparation depth (die size) do not affect the fracture strength.4 0Item Restricted MONOLITHIC AND SEMI-MONOLITHIC TRANSLUCENT ZIRCONIUM-DIOXIDE RESTORATIONS Aspects on design, material and strength(Malmo University, 2020) Bakitian, Fahad; Steyern, Per Vult vonSeveral clinical reports have shown high rates of clinical success associated with fixed dental restorations made of traditional zirconium-dioxide (zirconia). Clinical complications related to the design of the restorations do however occur as some aspects of design for optimal aesthetics are in conflict with design for optimal strength. Previous clinical and laboratory studies indicated that veneering porcelain and the connector represent the weak parts of the fully-veneered zirconia restorations where failure may occur. Although the clinical performance of such restorations has recently been reported to be comparable to metal-ceramic restorations, further improvements in design are still required. Restorations with monolithic design made of modified translucent zirconia materials offer an excellent solution to these clinical problems. One of the advantages of monolithic restoration is that such restorations can be prepared without the weak veneering material. Thus, this restoration design has a much higher load-bearing capacity compared to the veneered restorations since it provides additional space for the high-strength zirconia material. With regard to strength and aesthetics, the translucency of the former generation of monolithic translucent zirconia, which comes with equivalent mechanical properties to traditional zirconia, is insufficient. Recently, monolithic zirconia with high translucent properties was developed for highly aesthetic clinical uses. These new systems of translucent zirconia materials have limited capacity in terms of fracture strength and fracture toughness properties. Further, earlier studies have shown doubtful aging stability for these materials. Maintaining well-known strength properties ofzirconia restorations while providing a high aesthetic outcome is the ultimate goal for dental restorations such as single crowns (SCs) and fixed dental prostheses (FDPs). The optimum design for restorations made of the former generation of translucent zirconia could help prevent the risks associated with bilayered restorations and overcome the limitations of high-translucent monolithic restorations. Based on clinical needs and previous clinical observations, the overall aim of this thesis was to evaluate translucent and high-translucent zirconia restorations and the effect of design modifications, used to enhance the aesthetics, on fracture resistance. In the first three studies, I, II, and III, all the SCs and the FDPs were artificially aged and loaded to fracture. Fracture mode analysis in the different studies was performed visually and microscopically. In study I, fracture strength and fracture mode of veneered translucent zirconia SCs designed with different porcelain layer thicknesses were evaluated. Study II described different designs of partially veneered monolithic (semi-monolithic) SCs made of translucent zirconia and evaluated the effect of those designs on fracture resistance and fracture mode of crowns made of two generations of translucent zirconia materials. Study III investigated the load-bearing capacity and failure mode of monolithic zirconia FDPs with different connector designs achieved by using different embrasure shaping methods. Finally, study IV aimed to evaluate the influence of the framework designs on the stress distribution within tooth-supported semi-monolithic FDPs made of translucent zirconia material under simulated loads using a three-dimensional finite element analysis (3D-FEA). Simplified 3D solid models of prepared abutment teeth with different 3-unit FDPs based on the designs of studies II and III, were created. The designs of 3-unit FDPs included monolithic zirconia, semi- monolithic zirconia with 0.3 mm veneer thickness, semi-monolithic zirconia with 0.5 mm veneer thickness, semi-monolithic zirconia with 0.5 mm veneer thickness supported with cap design, and semi-monolithic zirconia with 0.5 mm veneer thickness supported with wave design. The outcomes of study I showed that translucent zirconia SCs can be veneered with a minimal thickness layer of 0.5 mm porcelain without showing significantly reduced fracture strength compared to traditionally veneered (1.0-2.0 mm) SCs. Fracture strength of micro-veneered SCs with a layer of porcelain (0.3 mm) is lower than that of traditionally veneered SCs but still within range of what may be considered clinically sufficient. Porcelain layers of 2.0 mm or thicker should be used only where the expected loads are low. All the SCs in groups 2.5 and 2.0 and more than 80% of the SCs in groups 1.0, 0.8 and 0.5 showed cohesive fracture mode. Conversely, there were significantly (p0.05) more complete fractures in group 0.3 compared to all other groups. The results of study II demonstrated that translucent and high- translucent zirconia SCs might be used in combination with a 0.3 mm micro-coating porcelain layer with semi-monolithic design to enhance the aesthetic properties of restorations without significantly decreasing fracture resistance of the SCs. If a 0.5 mm porcelain layer is needed for semi-monolithic SCs, wave design or cap design might be used to increase fracture resistance. The SCs made of translucent zirconia showed higher load at fracture compared to those made of high-translucent zirconia, regardless of design. All monolithic SCs, semi-monolithic SCs with 0.3 mm buccal veneer (100%), and all but one of semi-monolithic SCs with cap design (95%) showed complete fractures. Semi-monolithic SCs with wave design and semi-monolithic SCs with a 0.5 mm buccal veneer showed (70% and 55%, respectively) cohesive veneer fractures. The results of study III showed that sharp embrasures and interproximal separations made with diamond discs significantly decrease the load-bearing capacity of monolithic zirconia FDPs compared to monolithic FDPs made with blunt embrasures (p<0.001). Blunt embrasures in combination with localized porcelain build-up produce monolithic FDPs with high load-bearing capacity in relation to loads that might be expected under clinical use. Fracture mode of the FDPs fabricated with sharp embrasures and interproximal disc separations differed significantly compared to the FDPs with no occlusal embrasures, the FDPs with blunt embrasures, and the FDPs with interproximal porcelain separations (p<0.001). The findings of study IV confirmed that framework and veneer designs play a significant role in the stress distribution of the partially veneered zirconia FDPs under loading. The FDPs with zirconia frameworks with cap design minimize the maximum principal tensile stress in the veneering porcelain. The FDPs with 0.3 mm-veneering porcelain show low maximum principal tensile stress in the veneering porcelain, but the highest maximum shear stress at the zirconia- veneer interface. The FDPs with wave design of zirconia frameworks minimize the maximum shear stress considerably.12 0