Fabrication of Mechanically Robust PEG-Based Hydrogels for 3D Printing and Injection

Hydrogels, due to their unique characteristics, are ideal candidates for tissue engineering and regenerative medicine applications. However, their inherent softness and brittleness, resulting from their high water content and the nonuniform structure formed during the crosslinking process, can limit their applications in load-bearing tissues such as cartilage, tendons, and ligaments. The overall aim of this work was to enhance the mechanical performance of poly(ethylene glycol) (PEG)-based hydrogels using two distinct and straightforward strengthening strategies compatible with injection and various light-based 3D printing technologies. In Chapter 3, the strategy of creating relatively uniform networks using nucleophilic thiol-yne chemistry was applied to improve the mechanical performance of hydrogels by minimizing structural defects, which act as stress concentration zones during deformation. It was demonstrated that the mechanical properties could be tuned by varying parameters such as polymer content, molecular weight, and the architecture of the building blocks. To evaluate the effect of network uniformity on hydrogel mechanics, relatively non-uniform hydrogels were also prepared using identical building blocks but crosslinked via UV light. The results showed that the relatively uniform PBS-crosslinked gels were mechanically more robust than their UV-crosslinked counterparts, despite using the same building blocks. Furthermore, the mechanical properties correlated well with the crosslink and entanglement densities predicted by the Rubinstein– Panyukov model. Continuing with the strategy of fabricating relatively uniform hydrogels, Chapter 4 explored thiol-norbornene chemistry to create PEG-based gels. A comprehensive library of hydrogels was developed by varying the polymer content, the molecular weight of PEG-Norbornene and PEG-Thiol crosslinkers, and the molar ratio of reactive end groups. The structure-property relationships in these hydrogels were systematically analyzed, demonstrating that robust formulations suitable for loadbearing applications could be achieved. Additionally, it was shown that, regardless of formulation, these hydrogels exhibited rapid gelation kinetics, solidifying within seconds of light illumination. In Chapter 5, the photocurable hydrogel resins developed in Chapter 4 were utilized for injection and processing via two advanced light-based 3D printing technologies: digital light processing (DLP) and volumetric printing (VP). These resins were proved highly suitable for these applications due to their fast gelation kinetics upon light exposure. However, modifications were necessary to meet the specific requirements of each printing technology. The fast fabrication of complex structures (<32 seconds) without any supporting elements was demonstrated via VP, outperforming conventional layer-based fabrication methods. Additionally, the printed structures were mechanically robust immediately after fabrication, requiring no post-printing curing. In Chapter 6, an interpenetrating network (IPN) strategy was employed to create robust hydrogels by combining the thiol-yne PEG networks developed in Chapter 3 with sodium alginate networks using a straightforward one-pot preparation method. The effects of various parameters—such as the uniformity of the PEG network, the order of network formation, the characteristics of alginate, and the building blocks used—on the reinforcing effects were systematically studied. While the addition of alginate enhanced the elastic modulus and maximum stress in some formulations, its most pronounced effect was on the fracture energy of the gels. The findings of this chapter provide valuable insights into designing hydrogel formulations tailored to specific application requirements

Thermalization dynamics of entanglement and non-locality of filtered two-mode squeezed states

We explore how entanglement and non-locality evolve between specific spectral components of two-mode squeezed states in thermal environments. These spectral components are extracted from output modes using filters that are frequently utilized in optomechanical systems. We consider two distinct thermalization scenarios: one occurring in the vacuum state prior to entering the nonlinear crystal for squeezing and another after the generation of the two-mode squeezed vacuum but before passing through filters and detectors. Entanglement and non-locality generally remain at their peak when identical filters are applied throughout. In the first scenario, higher initial squeezing causes the entanglement dissipation to slow down at the beginning of the time evolution, followed by a progressive acceleration of entanglement dissipation over time. However, the dissipation rate of non-locality, even though it changes over time it moreover remains the same irrespective of the initial degree of squeezing. In the second scenario, greater squeezing results in a more rapid loss of both entanglement and non-locality. We identify the evolution of specific boundaries for entanglement and non-locality and the conditions for their optimization. Finally, for all the cases, increasing the thermal population of the environment enhances the rate of dissipation, whereas stronger interaction slows dissipation in a normalized dimensionless time scale.Funding. Horizon Europe Framework Programme (HORIZON-MSCA-2021) Marie Skłodowska-Curie Actions (101065991, SingletSQL). Acknowledgments. SA would like to thank Philippe Djorwé for his fruitful suggestions. The work has been supported by the European Union, MSCA GA no 101065991 (SingletSQL)

The impact of hydrothermally etched and ceria-coated soda-lime glass beads on CO2 reduction in a packed-bed dielectric barrier discharge plasma reactor

Carbon Capture and Utilization (CCU) provides a complementary solution to renewable energy technologies, such as solar, wind, and hydropower, to reduce CO2 emissions. It involves extracting CO2 from emission sources and converting it into valuable materials and fuels.1-4 An emerging approach for converting CO2 into value-added chemicals and fuels is plasma-catalytic reduction using a non-thermal plasma discharge.5 The non-thermal plasma, such as a dielectric barrier discharge (DBD) reactor, provides energy to dissociate and reduce CO2 molecules into products such as CO, and in the presence of an additional hydrogen source (e.g., CH4, H2, H2O), alkanes, alkenes, alkynes, alcohols, aldehydes, and ketones in a single-step process.5-7 Many interacting factors affect the CO2 conversion and energy efficiency in plasma reactors. While temperature, pressure, and reactor geometry play a role, packing with suitable (dielectric) materials and catalysts has shown promise to considerably improve performance through synergistic effects with the plasma discharge.8 Nevertheless, the impact of the material properties on the plasma performance is not yet fully understood. Limited research correlates the diverse outcomes of CO2 conversion (conversion degree, energy efficiency, and selectivity) with selectively altered material properties while keeping other material properties constant. To bridge this gap, our study aimed to alter/activate the surface characteristics of soda-lime glass packing material (i.e., beads) through hydrothermal etching. In addition, to examine the impact of a ceria coating on the plasma-catalytic CO2-splitting reaction, we deposited cerium cations onto the activated soda-lime glass surface to produce the coating. The fundamental properties that make ceria attractive as a catalyst include its high oxygen storage capacity and oxygen vacancy formation ability.9 Oxygen vacancies in the ceria lattice are hypothesized to promote reactivity towards the CO2 plasma species. This study concludes that increasing the surface roughness of soda-lime glass packing material in a DBD reactor reduces the degree of CO2-splitting. However, applying a ceria coating on top of this activated packing material improves the reduced conversion of CO2. References 1. Yu, K.M.K., et al., ChemSusChem, 2008. 1(11): p. 893. 2. Nunes, L.J.R., Environments, 2023. 10(4): p. 66. 3. Gizer, S.G., et al., International Journal of Energy Research, 2022. 46(12): p. 16241. 4. Al-Mamoori, A., et al., Energy Technology, 2017. 5(6): p. 834. 5. Snoeckx, R. and A. Bogaerts, Chemical Society Reviews, 2017. 46(19): p. 5805. 6. Bogaerts, A. and E.C. Neyts, ACS Energy Letters, 2018. 3(4): p. 1013. 7. Michielsen, I., et al., Chemical Engineering Journal, 2017. 326: p. 477. 8. Bogaerts, A., et al., Journal of Physics D: Applied Physics, 2020. 53(44): p. 443001. 9. Montini, T., et al., Chemical Reviews, 2016. 116(10): p. 5987

Prevalence, characteristics, and outcome of subclinical vasculitis in polymyalgia rheumatica: a retrospective cohort study

Objectives: Two recent meta-analyses reported subclinical vasculitis in 22-23% of patients with PMR. We aimed to evaluate the prevalence, characteristics, and outcome of subclinical vasculitis among our PMR patients. Methods: Consecutive patients with GCA/PMR spectrum disease with isolated PMR symptoms who underwent FDG PET imaging between 2003 and 2020 and who were followed for ≥6 months, were included retrospectively. Vasculitis was defined as FDG uptake ≥grade 2 in any vessel. Results: We included 337 patients, of whom 31 (9%) with subclinical vasculitis. Among those with subclinical vasculitis, 21 (58%) had isolated large vessel vasculitis, 3 (10%) had isolated cranial vasculitis and 7 (23%) had both cranial and large vessel vasculitis. The glucocorticoid (GC) starting dose and GC doses during follow-up were higher in those with subclinical vasculitis until 12 months after diagnosis (P < 0.001). There was no difference in the duration of GC treatment (25 vs 20 months, P ¼ 0.187). Cox proportional hazard regression analyses showed no difference in the proportion of patients able to stop GC (HR 0.78 [95% CI 0.49-1.25], P ¼ 0.303) and in the proportion of patients with relapse (HR 0.82 [95%CI 0.50-1.36], P ¼ 0.441). Conclusion: Only 9% of our PMR patients had subclinical vasculitis with a predilection for large vessel vasculitis. There were no differences in relapse rate and duration of GC treatment, however, those with subclinical vasculitis received higher GC doses until 12 months after diagnosis. Prospective interventional trials are needed to evaluate the outcome of PMR patients with and without subclinical vasculitis treated with a similar GC protocol.No specific funding was received from any bodies in the public, commercial or not-for-profit sectors to carry out the work described in this article. Disclosure statement: L.M.: Abbvie, Roche; L.B.: none; A.B.: none; T.M.: none; G.M.: none; K.V.L.: none; E.D.L.: AC immune, Actelion, Astra Zeneca, Boehringer Ingelheim, GSK, Novartis, Otsuka; S.V.: none; D.B.: Eli Lily, GSK, Roche

Penile length after penile implant surgery is determined by stretched penile length before surgery

Background: While various treatment modalities exist, penile prosthesis (PP) implantation offers a permanent solution for patients that do not respond to or are not suitable for other treatment options for erectile dysfunction. Aim: The aim of this study was to establish stretched penile length before surgery as a reliable determining factor of penile length after penile implant surgery. Methods: For this study, data on penile length before and after PP surgery from three European centers was analyzed. Penile length measurements were conducted preoperatively and postoperatively in different conditions using standardized techniques. Only virgin cases were included and a complete case analysis was performed. Outcome: The outcome of this study was the comparison of stretched penile length before and the inflated penile length after PP surgery. Results: Data on penile length before and after PP of 361 patients was analyzed. Preoperative stretched penile length was equal to postoperative inflated penile length in 33% of patients. The absolute mean difference between pre-surgery stretched and postoperative inflated lengths was 1.1 cm. No correlation was found between implanted cylinder length and postoperative penile length. Additionally, the choice of implant type did not significantly affect postoperative penile length outcomes. Clinical implications: Our findings confirm the reliability of preoperative stretched penile length as a tool for proper patient counseling before PP surgery. Strengths & Limitations: Although our study is overpowered, our results show that preoperative stretched penile length serves as a reliable predictor of postoperative penile length outcomes after PP surgery. By providing clinicians with a tool for patient counseling, our findings contribute to enhancing satisfaction and quality of life outcomes in patients undergoing PP implantation. Conclusion: Preoperative stretched penile length serves as a reliable predictor of postoperative penile length outcomes after PP surgery

Skills for Sustainable Tourism in Protected Areas: Training Needs Analysis

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The Building as Witness: visual narratives from Post-War Beirut

“Six of them hide in my body Two at the entrance, two on the second floor Two on the 24th” - Lyrics from the song Holiday Inn (March 21 – 29) by Mayssa Jallad (2023) Not far from the palm-lined corniche on Beirut's Mediterranean coastline, you will find standing tall the Holiday Inn Hotel. An abandoned shell of its former luxurious self and today an infamous monument to the Lebanese Civil War (1975 – 1990), with its surface still pockmarked and riddled with bullet holes. Its notoriety was cemented as a snipers’ den in what was dubbed the “Battle of the Hotels” at the onset of the civil war in 1975. This paper will refer to the notion of architecture and the building as a witness to history. Granting it anthropomorphic qualities. During wartime, the built environment is carved up by the warring factions into territories. Such was the case of Beirut during its civil war, the city was divided along religious affiliations between largely Muslim West Beirut and Christian East Beirut. Once buildings were occupied in these newly claimed territories, they often stood at the forefront of war and from which battles were waged. Extending the notion of the “building as a witness”, this paper will further refer to visual art representations of these once wartime-occupied buildings like the Holiday Inn Hotel and the Burj al-Murr. Utilising Visual Art/ History of Art as a new form/ modality for architectural historical narration. By making reference to select artworks depicting these buildings like the Monument for the Living (2002) by Marwan Rechmaoui, Holiday Inn Hotel ‘Seeking The Heights’ (2010) by Ayman Baalbaki and Lamia Ziadé’s Hotel War’s (2008)

From Experimental Models to Targeted Therapies for Oral Squamous Cell Carcinoma

Cancer remains a leading cause of death worldwide, with OSCC being one of the most aggressive forms of HNC. OSCC often develops unnoticed until advanced stages, making treatment challenging and survival rates low. Standard therapies, including surgery, chemotherapy, radiotherapy and immunotherapy, can be effective but frequently result in significant side effects and high recurrence rates. There is a critical need for better preclinical models and innovative treatments to improve patient outcomes. This thesis focuses on optimizing preclinical models for OSCC research and emphasizes the need for better platforms to test new therapies. A key objective was to refine and evaluate the 4NQO-induced OSCC rat model, which closely replicates human OSCC progression. Two methods of 4NQO administration (via drinking water and topical application) were compared. The study found that the drinking water method more effectively induced tumors that mirrored human OSCC in terms of histopathology and progression, making it a superior approach for future OSCC research. Given the limitations of current OSCC treatments, the thesis also explored emerging therapeutic approaches, including plasma-treated PBS and suicide gene therapy using DPSC. Plasma-treated PBS was investigated for its ability to selectively kill cancer cells through oxidative stress while sparing healthy tissue, offering a non-invasive potential therapy. The HSV1-TK/GCV study demonstrated that DPSC could serve as effective carriers for delivering suicide gene therapy, improving tumor targeting and reducing systemic toxicity. Furthermore, this gene therapy system was explored in multiple cancer models, underscoring its broader potential beyond OSCC. In conclusion, this research strengthens the 4NQO rat model as a valuable tool for studying OSCC and testing new treatments. Additionally, it highlights promising therapeutic innovations that could lead to more targeted, effective, and less invasive treatment options for OSCC and other malignancies, ultimately improving patient outcomes