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This article discusses the use of 3D-printed geometric shapes in creating Engineered Heart Tissue (EHT) for repairing heart muscle defects and drug testing. The researchers analyzed the surface-area-to-volume ratio (AS/V) of different shapes to determine the ideal EHT shape for cell survival. They found that structure A had higher cell survival compared to structure B, as evidenced by histological experiments, gene expression analysis, cytometric studies, and bioluminescence imaging. The study concludes that optimizing the geometry of EHTs can significantly improve cell survival. [Extracted from the article]

We present a study of the spectral characteristics of protons in the Earth's plasma sheet for various geomagnetic disturbance levels. The study is based on about 5400 h of data combined from the Cluster RAPID and CIS instruments obtained during the tail season (July-October). The overall proton spectral shape is generally that of a κ distribution, that is, resembling a Maxwellian at lower energies which smoothly merges into a power-law tail at higher energies. The actual spectral long-term slope depends on various magnetospheric driver parameters, but is on average around 3.5-4. During disturbed conditions, such as geomagnetic storm or substorm periods, a shift in the characteristic energy is observed. For two individual storms, we also found a hardening of the spectra. Unlike the electron spectra, we do not see any significant local time dependence in the spectral slope, but we find higher average ion fluxes in the dusk side. We also do not find any direct response in the energy spectra to changes in the interplanetary magnetic field or solar wind dynamic pressure. This suggests that energization of the ions are mainly due to internal processes in the plasma sheet. [ABSTRACT FROM AUTHOR]

The g factors of the metastable states P ofSr and D, D, D, and D ofBa have been measured using the atomic-beam magnetic resonance method. The metastable states were populated by an electric discharge within the atomic-beam source. From the measurements of rf transitions between the Zeeman levels ( m=+1)↔( m=−1) we obtained:Sr: g( P) =1.501124(10)Ba: g( D)=1.3340823 (10) g( D′)=1.1637406(11) g( D)=0.4985751(13) g( D′)=1.003 1449(10). The relativistic and diamagnetic corrections for the g factor of the P state of Sr have been calculated. With these and the Schwinger correction included we get g( P)=1.501119(12). [ABSTRACT FROM AUTHOR]

Objectives: Engineered Heart Tissue (EHT) is a promising tool to repair heart muscle defects and can additionally be used for drug testing. Due to the absence of an in vitro vascularization, EHT geometry crucially impacts nutrient and oxygen supply by diffusion capacity. We analyzed cardiomyocyte survival in different EHT geometries., Methods: Different geometries with varying surface-area-to-volume-ratios were calculated (structure A (Ring) AS/V = 58.47 mm 2 /440 μL 3 , structure B (Infinity) 25.86 mm 2 /440 μL 3 ). EHTs were generated from hiPSC-derived cardiomyocytes (4 × 10 6 ) and a fibrin/thrombin hydrogel. Cell viability was evaluated by RT-PCR, cytometric studies, and Bioluminescence imaging., Results: Using 3D-printed casting molds, spontaneously beating EHTs can be generated in various geometric forms. At day 7, the RT-PCR analyses showed a significantly higher Troponin-T value in ring EHTs, compared to infinity EHTs. In cytometric studies, we evaluated 15% more Troponin-T positive cells in ring (73% ± 12%), compared to infinity EHTs (58% ± 11%, p = 0.04). BLI visualized significantly higher cell survival in ring EHTs (ROI = A: 1.14 × 10 6 p/s and B: 8.47 × 10 5 p/s, p < 0.001) compared to infinity EHTs during longitudinal cultivation process., Conclusion: Use of 3D-printing allows the creation of EHTs in all desired geometric shapes. The geometry with an optimized surface-area-to-volume-ratio (ring EHT) demonstrated a significantly higher cell survival measured by RT-PCR, Bioluminescence imaging, and cytometric studies using FACS analysis., (© 2024 The Author(s). Artificial Organs published by International Center for Artificial Organ and Transplantation (ICAOT) and Wiley Periodicals LLC.)