Supersymmetric Baryogenesis in a Hybrid Inflation Model

We study baryogenesis in a hybrid inflation model which is embedded to the minimal supersymmetric model with right-handed neutrinos. Inflation is induced by a linear combination of the right-handed sneutrinos and its decay reheats the universe. The decay products are stored in conserved numbers, which are transported under the interactions in equilibrium as the temperature drops down. We find that at least a few percent of the initial lepton asymmetry is left under the strong wash-out due to the lighter right-handed (s)neutrinos. To account for the observed baryon number and the active neutrino masses after a successful inflation, the inflaton mass and the Majorana mass scale should be $10^{13}\,{\rm GeV}$ and ${\cal O}(10^{7}$-$10^{10})\,{\rm GeV}$, respectively.Comment: 19 pages, 2 figure

Sarcomere Imaging by Quantum Dots for the Study of Cardiac Muscle Physiology

We here review the use of quantum dots (QDs) for the imaging of sarcomeric movements in cardiac muscle. QDs are fluorescence substances (CdSe) that absorb photons and reemit photons at a different wavelength (depending on the size of the particle); they are efficient in generating long-lasting, narrow symmetric emission profiles, and hence useful in various types of imaging studies. Recently, we developed a novel system in which the length of a particular, single sarcomere in cardiomyocytes can be measured at ~30 nm precision. Moreover, our system enables accurate measurement of sarcomere length in the isolated heart. We propose that QDs are the ideal tool for the study of sarcomere dynamics during excitation-contraction coupling in healthy and diseased cardiac muscle

Possible helimagnetic order in Co4+-containing perovskites Sr1-xCaxCoO3

We systematically synthesized perovskite-type oxides Sr1-xCaxCoO3 containing unusually high valence Co4+ ions by a high pressure technique, and investigated the effect of systematic lattice change on the magnetic and electronic properties. As the Ca content x exceeds about 0.6, the structure changes from cubic to orthorhombic, which is supported by the first-principles calculations of enthalpy. Upon the orthorhombic distortion, the ground state remains to be apparently ferromagnetic with a slight drop of the Curie temperature. Importantly, the compounds with x larger than 0.8 show antiferromagnetic behavior with positive Weiss temperatures and nonlinear magnetization curves at lowest temperature, implying that the ground state is noncollinear antiferromagnetic or helimagnetic. Considering the incoherent metallic behavior and the suppression of the electronic specific heat at high x region, the possible emergence of a helimagnetic state in Sr1-xCaxCoO3 is discussed in terms of the band-width narrowing and the double-exchange mechanism with the negative charge transfer energy as well as the spin frustration owing to the next-nearest neighbor interaction.Comment: 13 pages, 4 figure

Sarcomere length-dependent Ca2+ activation in skinned rabbit psoas muscle fibers: coordinated regulation of thin filament cooperative activation and passive force

In skeletal muscle, active force production varies as a function of sarcomere length (SL). It has been considered that this SL dependence results simply from a change in the overlap length between the thick and thin filaments. The purpose of this study was to provide a systematic understanding of the SL-dependent increase in Ca2+ sensitivity in skeletal muscle, by investigating how thin filament “on–off” switching and passive force are involved in the regulation. Rabbit psoas muscles were skinned, and active force measurements were taken at various Ca2+ concentrations with single fibers, in the short (2.0 and 2.4 μm) and long (2.4 and 2.8 μm) SL ranges. Despite the same magnitude of SL elongation, the SL-dependent increase in Ca2+ sensitivity was more pronounced in the long SL range. MgADP (3 mM) increased the rate of rise of active force and attenuated SL-dependent Ca2+ activation in both SL ranges. Conversely, inorganic phosphate (Pi, 20 mM) decreased the rate of rise of active force and enhanced SL-dependent Ca2+ activation in both SL ranges. Our analyses revealed that, in the absence and presence of MgADP or Pi, the magnitude of SL-dependent Ca2+ activation was (1) inversely correlated with the rate of rise of active force, and (2) in proportion to passive force. These findings suggest that the SL dependence of active force in skeletal muscle is regulated via thin filament “on–off” switching and titin (connectin)-based interfilament lattice spacing modulation in a coordinated fashion, in addition to the regulation via the filament overlap

Myocardin Expression Is Regulated by Nkx2.5, and Its Function Is Required for Cardiomyogenesis

Nkx2.5 (also known as Csx) is an evolutionarily conserved cardiac transcription factor of the homeobox gene family. Nkx2.5 is required for early heart development, since Nkx2.5-null mice die before completion of cardiac looping. To identify genes regulated by Nkx2.5 in the developing heart, we performed subtractive hybridization by using RNA isolated from wild-type and Nkx2.5-null hearts at embryonic day 8.5. We isolated a mouse cDNA encoding myocardin A, which is an alternative spliced isoform of myocardin and the most abundant isoform in the heart from embryo to adult. The expression of myocardin A and myocardin was markedly downregulated in Nkx2.5-null mouse hearts. Transient-cotransfection analysis showed that Nkx2.5 transactivates the myocardin promoter. Inhibition of myocardin function in the teratocarcinoma cell line P19CL6 prevented differentiation into cardiac myocytes after dimethyl sulfoxide treatment. Myocardin A transactivated the promoter of the atrial natriuretic factor gene through the serum response element, which was augmented by bone morphogenetic protein 2 and transforming growth factor β-activated kinase 1. These results suggest that myocardin expression is regulated by Nkx2.5 and that its function is required for cardiomyogenesis

Stomach position evaluated using computed tomography is related to successful post-pyloric enteral feeding tube placement in critically ill patients: a retrospective observational study

Abstract Background Post-pyloric enteral feeding reduces respiratory complications and shortens the duration of mechanical ventilation. Blind placement of post-pyloric enteral feeding tubes (EFT) in patients with critical illnesses is often the first-line method because endoscopy or fluoroscopy cannot be easily performed at bedside; however, difficult placements regularly occur. We reported an association between the stomach position caudal to spinal level L1–L2, evaluated by abdominal radiographs after placement, and difficult placement; however, this method could not indicate difficulty before EFT placement. The aim of our study was to evaluate the association between stomach position, estimated using computed tomography (CT) images taken before the blind placement of the post-pyloric EFT, and the difficulty of EFT placement. Methods Data from patients aged ≥ 20 years who underwent post-pyloric EFT in our intensive care unit were obtained retrospectively. Logistic regression analysis was used to evaluate the association between successful initial EFT placement and explanatory variables, including stomach position estimated by CT. Two cut-off values were used: caudal to L1–L2 based on a previous study and the best cut-off value calculated by the receiver operating characteristic curve. Variable selection was performed backward stepwise using Akaike's Information Criterion. Results Of the total of 453 patients who were enrolled, the success rate of the initial EFT placement was 43.5%. The adjusted odds ratio for successful initial EFT placement of the stomach position caudal to L1–L2 was 0.61 (95% confidence interval: 0.41–1.07). Logistic regression analysis, including the stomach position caudal to L2–L3, calculated as the best cut-off value, indicated that stomach position was an independent factor for failure of initial EFT placement (adjusted odds ratio, 0.55; 95% confidence interval: 0.33–0.91). Conclusions Stomach position evaluated using CT images was associated with successful initial post-pyloric EFT placement. The best cut-off value of the greater curvature of the stomach to predict the success or failure of the first attempt was spinal level L2–L3. Trial registration University Hospital Medical Information Network Clinical Trials Registry (UMIN000046986; February 28, 2022). https://center6.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R00005215