PIC methods in astrophysics: Simulations of relativistic jets and kinetic physics in astrophysical systems

The Particle-In-Cell (PIC) method has been developed by Oscar Buneman, Charles Birdsall, Roger W. Hockney, and John Dawson in the 1950s and, with the advances of computing power, has been further developed for several fields such as astrophysical, magnetospheric as well as solar plasmas and recently also for atmospheric and laser-plasma physics. Currently more than 15 semi-public PIC codes are available which we discuss in this review. Its applications have grown extensively with increasing computing power available on high performance computing facilities around the world. These systems allow the study of various topics of astrophysical plasmas, such as magnetic reconnection, pulsars and black hole magnetosphere, non-relativistic and relativistic shocks, relativistic jets, and laser-plasma physics. We review a plethora of astrophysical phenomena such as relativistic jets, instabilities, magnetic reconnection, pulsars, as well as PIC simulations of laser-plasma physics (until 2021) emphasizing the physics involved in the simulations. Finally, we give an outlook of the future simulations of jets associated to neutron stars, black holes and their merging and discuss the future of PIC simulations in the light of petascale and exascale computing.Comment: 117 pages, 44 figures, Invited review article for Living Reviews in Computational Astrophysics, comments are welcomed, Living Reviews in Computational Astrophysics, submitted, 2020, the revised version resubmitted in December 2020, the second revised revision resubmitted in April, 2021, publishe

Electromagnetically levitated vibration isolation system for the manufacturing process of silicon monocrystals

This paper introduces a study on an Electromagnetically Levitated Vibration Isolation System (ELVIS) for isolation control of large-scale vibration. This system features no mechanical contact between the isolation table and the installation floor, using a total of four electromagnetic actuators which generate magnetic levitation force in the vertical and horizontal directions. The configuration of the magnet for the vertical direction is designed to prevent any generation of restoring vibratory force in the horizontal direction. The isolation system is set so that vibration control effects due to small earthquakes can be regulated to below 5(gal) versus horizontal vibration levels of the installation floor of up t 25(gal), and those in the horizontal relative displacement of up to 30 (mm) between the floor and levitated isolation table. In particular, studies on the relative displacement between the installation floor and the levitated isolation table have been made for vibration control in the horizontal direction. In case of small-scale earthquakes (Taft wave scaled: max. 25 gal), the present system has been confirmed to achieve a vibration isolation to a level below 5 gal. The vibration transmission ratio of below 1/10 has been achieved versus continuous micro-vibration (approx. one gal) in the horizontal direction on the installation floor

Generalised Acanthosis Nigricans in Childhood with Short Stature Associated with Poor Response to Growth Hormone Provocation

Acanthosis nigricans (AN) is a skin disorder characterised by skin hyperpigmentation and thickening, especially in the intertriginous regions. AN is usually classified as either malignant, benign, obesity-associated, syndromic, unilateral, acral, drug-induced and mixed (1). A generalised form of AN frequently occurs together with internal malignancy in adult patients, but it is rare in childhood (2-7). Here, we report a paediatric case of generalised AN associated with short stature accompanied with decreased growth hormone levels.ArticleACTA DERMATO-VENEREOLOGICA. 94(4):486-487 (2014)journal articl

Rashba-Dresselhaus spin-orbit coupling and polarization-coupled luminescence in an organic single crystal microcavity

Spin-orbit coupling (SOC) of light plays a fundamental photophysics that is important for various fields such as materials science, optics, and quantum technology, contributing to the elucidation of new physical phenomena and the development of innovative applications. In this study, we investigate the impact of SOC in a microcavity system using the highly oriented molecular crystal. The unique molecular alignment of our crystal creates substantial optical anisotropy, enabling the observation of significant SOC effects within a microcavity form. Through angle-resolved photoluminescence measurements and theoretical calculations, the presence of Rashba-Dresselhaus (RD) SOC in the lower branch of polariton modes is revealed. We have observed for the first time polarization-coupled emission from polariton modes due to the RD-SOC effect in a microcavity with a medium having both strong light-matter coupling and strong optical anisotropy. Theoretical investigations further elucidate the intricate interplay between the RD-SOC effect and anisotropic light-matter coupling, leading to the emergence of both circularly and diagonally polarized mode splittings. This study not only advances our understanding of optical SOC in microcavities but also highlights the potential of highly oriented molecular crystals in manipulating SOC effects without external electric or magnetic fields. These findings offer greatly promising platforms for developing topological photonics and quantum technologies

Model-Informed Vancomycin Dosing Optimization to Address Delayed Renal Maturation in Infants and Young Children with Critical Congenital Heart Disease

This is the peer reviewed version of the following article, Shimamoto Y., Fukushima K., Mizuno T., et al. Model-Informed Vancomycin Dosing Optimization to Address Delayed Renal Maturation in Infants and Young Children with Critical Congenital Heart Disease. Clinical Pharmacology and Therapeutics 115, 239 (2024), which has been published in final form at https://doi.org/10.1002/cpt.3095. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited.Ensuring safe and effective drug therapy in infants and young children often requires accounting for growth and organ development; however, data on organ function maturation are scarce for special populations, such as infants with congenital diseases. Children with critical congenital heart disease (CCHD) often require multiple staged surgeries depending on their age and disease severity. Vancomycin (VCM) is used to treat postoperative infections; however, the standard pediatric dose (60–80 mg/kg/day) frequently results in overexposure in children with CCHD. In this study, we characterized the maturation of VCM clearance in pediatric patients with CCHD and determined the appropriate dosing regimen using population pharmacokinetic (PK) modeling and simulations. We analyzed 1,254 VCM serum concentrations from 152 postoperative patients (3 days–13 years old) for population PK analysis. The PK model was developed using a two-compartment model with allometrically scaled body weight, estimated glomerular filtration rate (eGFR), and postmenstrual age as covariates. The observed clearance in patients aged ≤ 1 year and 1–2 years was 33% and 40% lower compared with that of non-CCHD patients, respectively, indicating delayed renal maturation in patients with CCHD. Simulation analyses suggested VCM doses of 25 mg/kg/day (age ≤ 3 months, eGFR 40 mL/min/1.73 m2) and 35 mg/kg/day (3 months < age ≤ 3 years, eGFR 60 mL/min/1.73 m2). In conclusion, this study revealed delayed renal maturation in children with CCHD, could be due to cyanosis and low cardiac output. Model-informed simulations identified the lower VCM doses for children with CCHD compared with standard pediatric guidelines

Optimizing Charge Switching in Membrane Lytic Peptides for Endosomal Release of Biomacromolecules.

Endocytic pathways are practical routes for the intracellular delivery of biomacromolecules. Along with this, effective strategies for endosomal cargo release into the cytosol are desired to achieve successful delivery. Focusing on compositional differences between the cell and endosomal membranes and the pH decrease within endosomes, we designed the lipid-sensitive and pH-responsive endosome-lytic peptide HAad. This peptide contains aminoadipic acid (Aad) residues, which serve as a safety catch for preferential permeabilization of endosomal membranes over cell membranes, and His-to-Ala substitutions enhance the endosomolytic activity. The ability of HAad to destabilize endosomal membranes was supported by model studies using large unilamellar vesicles (LUVs) and by increased intracellular delivery of biomacromolecules (including antibodies) into live cells. Cerebral ventricle injection of Cre recombinase with HAad led to Cre/loxP recombination in a mouse model, thus demonstrating potential applicability of HAad in vivo

Preliminary reports of the Quaternary sediment core drilled in Nakatokushima-cho Tokushima City, West Japan

A 80 m-long borehole core (TK-B-1) drilled in the Tokushima Plain was examined. Based on the sedimentary facies, volcanic ash layers, pollen fossils and radiocarbon dates, this core was divided into the following 13 units. Unit 1 is a metamorphic rock that forms the base of the Tokushima Plain. Units 3 to 8 are Pleistocene and consist of marine and fluvial strata. Units 12-10 are considered to be Alluvium based on radiocarbon dates, and K-Ah tephra found in Unit 11. In Unit 10, we found a volcanic glass concentration derived from AT tephra, but the concentration is a possibility of rework. We intend to reveal the subsurface geological structure of the Tokushima Plain based on the database of borehole data, lithologic stratigraphy, volcanic ash stratigraphy and biostratigraphy