Application of matrix product states to the Hubbard model in one spatial dimension

We investigate the application of matrix product states to the Hubbard model in one spatial dimension with both of open and periodic boundary conditions. We develop the variatinal method that the optimization of the variational parameters is carried out locally and sequentially in the framework of matrix product operators (MPO) by including the sign, due to the anti-commutation relation of fermion operators, in the matrix element of MPO. The numerical accuracy of the ground state energy is examined.Comment: 5 pages, 2 figure

Theoretical Study on the Detection of Tilted Lipid Bilayers Using Surface Plasmon Resonance Techniques

Effective refractive indices detected using surface plasmon resonance techniques are calculated as a function of the tilt angle of lipid bilayers in a multilayered model. The changes in the effective refractive indices are derived from the shift of an excitation angle of surface plasmon. To obtain effective refractive index plots, we determined refractive index changes in the lipid bilayers with 3 and 5 nm thicknesses as a function of tilt angle and obtained a relationship between the effective refractive index and tilt angle. We also showed that the effective refractive index depended on the lipid bilayers thickness and anisotropic permittivities, which vary with interchain distance

In-vitro Culture with a Tilting Device in Chemically Defined Media During Meiotic Maturation and Early Development Improves the Quality of Blastocysts Derived from In-vitro Matured and Fertilized Porcine Oocytes

Under physiological conditions, mammalian oocytes and embryos appear to be stimulated not only chemically but also mechanically, such as by compression, shear stress and/or friction force in the follicle and female reproductive tract. The present study was undertaken to examine the effects of kinetic culture with a tilting device in chemically defined media during in vitro maturation (IVM) of porcine oocytes and in vitro culture (IVC) following in vitro fertilization (IVF) on the early developmental competence and quality of blastocysts. After culture in a chemically defined IVM medium, modified porcine oocyte medium (mPOM) containing gonadotropins and dibutyryl cAMP for 20 h, the mean diameter of the cumulus-oocyte complexes (COCs) was larger in the tilting culture than in the static controls, whereas the diameter of the oocytes did not differ. When culture of the COCs was continued additionally in a fresh medium without gonadotropins and dibutyryl cAMP for 24 h, the incidences of oocytes completing GVBD and developing to the metaphase-II stage did not differ between the tilting and static culture systems. Furthermore, the sperm penetration after IVF and developmental competence of the oocytes to the blastocyst stage were not different between the tilting and static systems during IVM and IVC. However, tilting culture during both IVM and IVC had a significant positive effect on the number of cells per blastocyst (P<0.05). These observations indicate that tilting culture during IVM and IVC in chemically defined media improves the quality of blastocyst, as determined by the number of cells per blastocyst, without any effects on penetrability and developmental competence

Restructuring in bimetallic core-shell nanoparticles: Real-time observation

The formation process of core-shell bimetallic nanoparticles synthesized by sputtering onto a substrate is observed in real time using an originally developed acoustic technique. The technique enables us to evaluate the structural change of nanoparticles at room temperature without contacting the nanoparticles or substrate. In the experiments, the sputtering of metal A followed by metal B tended to form B-shell/A-core nanoparticles. However, in Pd-Au alloy system, notable restructuring occurred during synthesis, resulting in the formation of A-shell/B-core nanoparticles. The formation process is analyzed using the molecular dynamics simulation, revealing that this restructuring occurs on a short timescale, and high diffusivity of Au plays an important role.Nakamura Nobutomo, Matsuura Koji, Ishii Akio and Ogi Hirotsugu. Restructuring in bimetallic core-shell nanoparticles: Real-time observation. Physical Review B, 105, 125401, 2022. https://doi.org/10.1103/PhysRevB.105.125401

Hydrophobic Silicone Elastomer Chamber for Recording Trajectories of Motile Porcine Sperms without Adsorption

Motile porcine sperms adhere to hydrophilic materials such as glass and plastics. The adsorption of sperms to a hydrophobic poly(dimethylsiloxane) (PDMS) membrane is less compared with that to glass. We investigated the linear velocity (LV) and amplitude of lateral head displacement (ALHD) of motile porcine sperm on glass and PDMS preparations using computer-assisted sperm analysis (CASA). Significant decreases were observed in the 15-min LV (P<0.05) and ALHD (P<0.05) in motile porcine sperm on glass preparations compared with those on PDMS preparations. These differences were due to adsorption of the head and/or neck to hydrophilic substrates. Because of the elasticity of PDMS, we propose that a PDMS membrane should be used for CASA. To investigate the dynamics of motile porcine sperms with microfluidics, we do not recommend plasma treatment to bond PDMS and glass in the microchannel preparation; instead, we suggest that a PDMS molding process without plasma treatment be used for preparation of microfluidic channels

Spiral Trajectory Modulation of Rheotaxic Motile Human Sperm in Cylindrical Microfluidic Channels of Different Inner Diameters

We investigated the relationship between human sperm rheotaxis and motile sperm trajectories by using poly-(dimethylsiloxane) (PDMS)-based cylindrical microfluidic channels with inner diameters of 100 μm, 50 μm, and 70 μm, which corresponded to the inner diameter of the human isthmus, the length of a sperm and a diameter intermediate between the two, respectively. We counted the number of rheotaxic sperm and sperm with spiral motion. We also analyzed motile sperm trajectories. As the cylindrical channel diameter was decreased, the percentage of sperm cells exhibiting rheotaxis, the percentage of sperm cells exhibiting spiral motion, the frequency-to-diameter ratio of the sperm cells’ spiral trajectories, and the surface area of the microfluidic channel increased, while the flagellar motion at the channel wall decreased. The percentage of sperm exhibiting a spiral trajectory and the frequency-to-diameter ratio of the sperm cells’ spiral trajectories were thus affected by the channel diameter. Our findings suggest that the oviduct structure affects the swimming properties of sperm cells, guiding them from the uterus to the ampulla for egg fertilization. These results could contribute to the development of motile sperm-sorting microfluidic devices for assisted reproductive technologies

Proteome of the aging mice heart

Aging induces pathological cardiovascular changes such as cardiac dysfunction and arteriosclerosis. With aging, heart cells, especially, become more susceptible to lethal damage. In this report, we tried to understand the precise mechanism of myocardial change resulting from aging by examining the heart proteome in aging mice using two-dimensional gel electrophoresis (2DE). The proteins were stained with fluorescence dyes (SYPRO Ruby and Pro-Q Diamond) and identified by subsequent MALDI-TOF-MS / MS. As a result, markedly altered levels of 14 proteins and 7 phosphoproteins were detected in the hearts of 3-, 7-, 11-, and 20-month-old mice. The functions of these identified proteins and phosphoproteins were energy metabolism, muscle contraction, glycolysis, and cytoskeletal support. Additionally, the results of Western blotting confirmed changes in the expression of FTH, CPNE5, and SUCLA2. These findings showed that aging modified the expression of proteins and phosphoproteins in the heart. We suggest that changes in the expression of these proteins are critical to the development of cardiac dysfunction resulting from aging