Filament-Reinforced 3D Printing of Clay.

This research resulted in the development of a method that can be used for filament-reinforced 3D printing of clay. Currently, clay-based elements are mixed with randomly dispersed fibrous materials in order to increase their tensile strength. The advantages of taking this new approach to create filament-reinforced prints are the increased bridging ability while printing, the increased tensile strength of the dried elements, and the achievement of non-catastrophic failure behavior. The research methodology used involves the following steps: (1) evaluating properties of various filament materials with respect to multiple criteria, (2) designing a filament guiding nozzle for co-extrusion, and (3) conducting a comprehensive testing phase for the composite material. This phase involves comparisons of bridging ability, tensile strength evaluations for un-reinforced clay prints and filament-reinforced prints, as well as the successful production of an architectural brick prototype. (4) Finally, the gathered results are subjected to thorough analysis. Compared to conventional 3D printing of clay, the developed method enables a substantial increase in bridging distance during printing by a factor of 460%. This capability facilitates the design of objects characterized by reduced solidity and the attainment of a more open, lightweight, and net-like structure. Further, results show that the average tensile strength of the reinforced sample in a dry state exhibited an enhancement of approximately 15%. The combination of clay's ability to resist compression and the filament's capacity to withstand tension has led to the development of a structural concept in this composite material akin to that of reinforced concrete. This suggests its potential application within the construction industry. Producing the prototype presented in this research would not have been possible with existing 3D printing methods of clay.

Basic Research of Material Properties of Mycelium-Based Composites.

The subject of this research is growing mycelium-based composites and exploring their basic material properties. Since the building industry is responsible for a large amount of annual CO2 emissions, rethinking building materials is an important task for future practices. Using such composites is a carbon-neutral strategy that offers alternatives to conventional building materials. Yet, in order to become competitive, their basic research is still needed. In order to create mycelium-based composites, it was necessary to establish a sterile work environment and develop shaping procedures for objects on a scale of architectural building elements. The composite material exhibited qualities that make it suitable for compression-only structures, temporary assemblies, and acoustic and thermal insulation. The methodology includes evaluating several substrates, focused on beech sawdust, with two mycelium strains (Pleurotus ostreatus and Ganoderma lucidum), density calculations, compression tests, three-point flexural tests and capillary water absorption. The results of this study are presented through graphical and numerical values comparing material and mechanical properties. This study established a database for succeeding investigations and for defining the potentials and limitations of this material. Furthermore, future applications and relevant examinations have been addressed.

Association of PC and AT levels in the early phase of STEMI treated with pPCI with LV systolic function and 6-month MACE.

OBJECTIVES: To examine a relationship between protein C (PC) and antithrombin III (AT III) activities with ejection fraction of left ventricle (EFLV), in the early phase of acute ST-elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (pPCI), and to investigate whether PC and AT III are associated with major adverse cardiovascular events (MACE) within 6 months following from pPCI. PATIENTS AND METHODS: The research had a prospective character and included 357 patients who had, following the diagnosis of the STEMI, undergone pPCI at the Clinic of Cardiology and Emergency Internal Medicine, Military Medical Academy, Belgrade, Serbia, from January 2010 until April 2019. RESULTS: The EFLV positively correlated with PC values (rho = 0.229). There was a statistically significant increase in the PC values between patients with MACE compared with those without MACE at 6 months' follow-up evaluation (p < 0.0001). Also, significant difference in PC values between patients who died in hospital and those who were alive at 6 months' follow-up (p < 0.01) was observed. PC values were different across different EFLV groups (p < 0.001), increasing from the 1st to the 4th EFLV quartiles: the median and the interquartile values for the 1st, 2nd, 3rd and 4th quartiles were 1.0400IU/l ± 0.15, 1.1400IU/l ± 0.15, 1.1350IU/l ± 0.16 and 1.2200IU/l ± 0.14, respectively. CONCLUSION: Increased PC activity in the early phase of STEMI is associated with higher EFLV 5 days after the pPCI as well as with MACE at 6 months after the pPCI.

Biomarkers for the prediction of early pulmonary embolism related mortality in spontaneous and provoked thrombotic disease.

Factors associated with provoked PE may influence a biomarker's predictive value for the primary outcome. The aim of this study was to investigate the value of BNP, cTnI, CRP and D-Dimer measurements taken soon after hospital admission for the prediction of 30-day PE-caused death in patients with spontaneous versus provoked PE.Data were extracted from a pool of 726 consecutive PE patients enrolled in the multicenter Serbian PE registry. Blood concentrations of BNP, cTnI, CRP and D-dimer were measured during the first 24 h of hospitalization. BNP blood level had strong predictive value for the primary outcome in spontaneous PE (c-statistics 0.943, 95% CI 0.882-1.000, p = .001) and a slightly lower predictive outcome in provoked PE (c-statistics 0.824, 95% CI 0.745-0.902, p < .001). NRI and IDI showed that none of the markers, when added to BNP, could improve Cox regression prediction models for 30-day PE-related mortality in either the spontaneous or provoked PE group. Blood levels of BNP measured during the first 24 h of hospital admission had an excellent predictive value for 30-day PE-related mortality in spontaneous PE and slightly lower predictive value in provoked PE, whereas CRP, cTnI and D-Dimer did not contribute significantly to the predictive value of BNP in either group.

Lower plasma protein C activity is associated with early myocardial necrosis and no-reflow phenomenon in patients with ST elevation myocardial infarction.

Background: Activity of protein C has important role in the development of early necrosis and no-reflow phenomenon in patients with ST-segment elevation myocardial infarction (STEMI) after successful primary percutaneous coronary intervention (pPCI). Methods: We examined association between plasma activity of protein C, antithrombin, coagulation factors II, VII, VIII and fibrinogen to early formation of new Q-waves (myocardial necrosis) before pPCI and early ST-segment resolution (microcirculatory reperfusion) after pPCI in patients with acute STEMI. According to ischaemic time, patients were considered as early or late presenters. 12-lead ECG was analysed for the presence of new Q-wave at admission and for significant ST-segment resolution 60 minutes after primary PCI. Results: In early presenters' group, protein C activity was significantly lower in patients who did not achieve significant ST-segment resolution after pPCI compared to patients who did (1.11 IU/L vs. 0.99 IU/L, p = .006) and in patients who had new Q-waves compared to group who had not (1.04 UI/l vs. 1.11 IU/L, p = .038). There was significant negative correlation between protein C activity and maximal CK-MB levels (R2 = 0.06, p = .009) and BNP levels (R2 = 0.109, p = .003) and significant positive correlation between protein C activity with LVEF (R2 = 0.065, constant = 33.940, b = 11.968, p = .007) in early STEMI presenters. There were no differences between the activity of other examined haemostasis factors. Conclusion: Therefore we concluded that STEMI patients with early myocardial necrosis and no-reflow phenomenon after pPCI have lower activity of plasma protein C levels.

Differences between activities of coagulation factors after one month of therapy with different direct oral anticoagulant in pulmonary embolism patients.

WHAT IS KNOWN AND OBJECTIVE: Direct oral anticoagulants (DOACs) are frequently used for the treatment of pulmonary embolism (PE), but both clinical and laboratory data comparing their efficacy and safety are conflicting. This study investigated and compared the impact of three DOACs (apixaban, rivaroxaban and dabigatran) on coagulation cascade in acute PE patients. METHODS: After the initial treatment, acute PE patients were randomly allocated to one of three groups, and treatment continued using one of the three DOACs. Following 1 month of treatment, the activity of factors II, VII and VIII, as well as protein C, antithrombin, D-dimer and fibrinogen, were measured, and the values were compared between the groups. RESULTS AND DISCUSSION: One hundred consecutive PE patients were included. The mean values for the activity of factors II and VII and protein C were higher in patients on apixaban than in patients on rivaroxaban (1.45 ± 1.12 (IU/mL) vs 1.13 ± 0.92 (IU/mL), P < 0.001; 1.24 ± 1.10 (IU/mL) vs 1.05 ± 0.98 (IU/mL), P = 0.024 and 1.15 ± 0.62 vs 1.02 ± 0.68 (IU/mL), P = 0.019, respectively). The mean of factor II activity and the median of factor VIII activity were also significantly higher in patients on apixaban than in patients on dabigatran (1.45 ± 1.12 vs 1.20 ± 0.96 (IU/mL), P = 0.003 and 2.9 (2.0-4.0) vs 2.1 (1.5-2.7) (IU/mL), P = 0.001, respectively). No difference was noticed in D-dimer concentrations, or in the activity of the other factors measured. Additionally, no difference was noticed between the rivaroxaban and dabigatran groups. WHAT IS NEW AND CONCLUSION: Apixaban had a significantly higher thrombin activity, above the laboratory determined normal range, compared to patients on rivaroxaban and dabigatran. This higher thrombin activity in patients on apixaban may contribute to a better haemostatic response during the therapy or increased prothrombotic state after therapy interruption.