Strain-shear coupling in bilayer MoS2

Layered materials such as graphite and transition metal dichalcogenides have extremely anisotropic mechanical properties owing to orders of magnitude difference between in-plane and out-of-plane interatomic interaction strengths. Although effects of mechanical perturbations on either intra- or inter-layer interactions have been extensively investigated, mutual correlations between them have rarely been addressed. Here we show that layered materials have an inevitable coupling between in-plane uniaxial strain and interlayer shear. Because of this, the uniaxial in-plane strain induces an anomalous splitting of the degenerate interlayer shear phonon modes such that the split shear mode along the tensile strain is not softened but hardened contrary to the case of intralayer phonon modes. We confirm the effect by measuring Raman shifts of shear modes of bilayer MoS2 under strain. Moreover, by analyzing the splitting, we obtain an unexplored off-diagonal elastic constant, demonstrating that Raman spectroscopy can determine almost all mechanical constants of layered materials.Comment: 36 pages, 10 figure

Flocking of two unfriendly species: The two-species Vicsek model

We consider the two-species Vicsek model (TSVM) consisting of two kinds of self-propelled particles, A and B, that tend to align with particles from the same species and to antialign with the other. The model shows a flocking transition that is reminiscent of the original Vicsek model: it has a liquid-gas phase transition and displays micro-phase-separation in the coexistence region where multiple dense liquid bands propagate in a gaseous background. The interesting features of the TSVM are the existence of two kinds of bands, one composed of mainly A particles and one mainly of B particles, the appearance of two dynamical states in the coexistence region: the PF (parallel flocking) state in which all bands of the two species propagate in the same direction, and the APF (antiparallel flocking) state in which the bands of species A and species B move in opposite directions. When PF and APF states exist in the low-density part of the coexistence region they perform stochastic transitions from one to the other. The system size dependence of the transition frequency and dwell times show a pronounced crossover that is determined by the ratio of the band width and the longitudinal system size. Our work paves the way for studying multispecies flocking models with heterogeneous alignment interactions

Suppression of discontinuous phase transitions by particle diffusion

We investigate the phase transitions of the $q$-state Brownian Potts model in two dimensions (2d) comprising Potts spins that diffuse like Brownian particles and interact ferromagnetically with other spins within a fixed distance. With extensive Monte Carlo simulations we find a continuous phase transition from a paramagnetic to a ferromagnetic phase even for $q>4$. This is in sharp contrast to the existence of a discontinuous phase transition in the equilibrium $q$-state Potts model in 2d with $q>4$. We present detailed numerical evidence for a continuous phase transition and argue that diffusion generated dynamical positional disorder suppresses phase coexistence leading to a continuous transition.Comment: revised version (8 pages with 9 figures

Synthesis of Microscopic Cell Images Obtained from Bone Marrow Aspirate Smears through Generative Adversarial Networks

Every year approximately 1.24 million people are diagnosed with blood cancer. While the rate increases each year, the availability of data for each kind of blood cancer remains scarce. It is essential to produce enough data for each blood cell type obtained from bone marrow aspirate smears to diagnose rare types of cancer. Generating data would help easy and quick diagnosis, which are the most critical factors in cancer. Generative adversarial networks (GAN) are the latest emerging framework for generating synthetic images and time-series data. This paper takes microscopic cell images, preprocesses them, and uses a hybrid GAN architecture to generate synthetic images of the cell types containing fewer data. We prepared a single dataset with expert intervention by combining images from three different sources. The final dataset consists of 12 cell types and has 33,177 microscopic cell images. We use the discriminator architecture of auxiliary classifier GAN (AC-GAN) and combine it with the Wasserstein GAN with gradient penalty model (WGAN-GP). We name our model as WGAN-GP-AC. The discriminator in our proposed model works to identify real and generated images and classify every image with a cell type. We provide experimental results demonstrating that our proposed model performs better than existing individual and hybrid GAN models in generating microscopic cell images. We use the generated synthetic data with classification models, and the results prove that the classification rate increases significantly. Classification models achieved 0.95 precision and 0.96 recall value for synthetic data, which is higher than the original, augmented, or combined datasets

On the Species Identification of Korean Geoduck Clam (<i>Panopea</i> sp. 1) Based on the Morphological and Molecular Evidence

The geoduck clam is a high-value species in South Korea. However, the molecular and morphological characteristics of geoduck clams from the southern coast of South Korea remain unexamined. The accurate identification of native geoduck clams is crucial for their conservation and management. Therefore, this study used a combination of molecular and morphological analyses to characterize native geoduck clams from the southern coast of South Korea. Based on complete mitochondrial genome and morphological analyses, the native species of geoduck clam from this study area was identified as Panopea sp. 1. The complete mitochondrial genome sequencing of Panopea sp. 1 revealed a total of 16,225 bp in length with 37 genes (13 protein-coding genes, 22 tRNA genes, and 2 rRNA genes). It was also shown that Panopea sp. 1 belongs to the family Hiatellidae based on a phylogenetic analysis tree with 11 bivalve species. In particular, Panopea sp. 1 is closely related to three other Panopea species (Panopea sp., Panopea abrupta, and Panopea japonica). The phylogenetic analysis correlated with the morphological analysis. Overall, this is the first reliable record of Panopea sp. 1 in South Korea. These findings provide a basis for accurate species identification based on morphological characteristics and complete mitochondrial genome sequencing

Effects of electroconvulsive shock on the phosphorylation of DARPP-32 in rat striatum

Dopamine- and cAMP-regulated phosphoprotein with molecular weight 32 kDa (DARPP-32) is a key integrative molecule in the dopaminergic and glutamatergic signaling pathways in the striatum. Electroconvulsive shock (ECS), which induces massive neuronal depolarization, can activate various signaling pathways. In this study we investigated whether ECS could affect the phosphorylation status of DARPP-32. Male Sprague-Dawley rats underwent ECS and were sacrificed by decapitation at 0, 2, 10, 60, and 180 min after treatment. The phosphorylations of Thr34 and Thr75 residues of DARPP-32 and Ser159 residue of cyclin-dependent kinase 5 (CDK5) were investigated in the striatum. The activity of protein phosphatase 1 (PP1) and the binding between DARPP-32 and PP1 were also analyzed. Thr34 phosphorylation of DARPP-32 increased immediately after ECS and this state was maintained for more than 60 min. The activity of PP1 decreased and the binding between PP1 and DARPP-32 increased in accordance with this phosphorylation pattern. However, the phosphorylation at Thr75 showed no significant change except for an initial transient decrease. The phosphorylation of CDK5, which is responsible for Thr75 phosphorylation of DARPP-32, did not exhibit significant fluctuations. Our findings indicate that ECS increases Thr34 phosphorylation of DARPP-32, and thus inhibits the activity of PP1. (c) 2008 Elsevier Ireland Ltd. All rights reserved.This studywas supported by a grant from the Korea Research Foundation (Grant No. E00196), a Seoul National University Hospital Research Grant (05-2005-002-0), and a grant from the Brain Research Center of the 21st Century Frontier Research Program funded by the Ministry of Science and Technology (Grant No.M103KV010012-06K2201- 01210), Republic of Korea.Rosa DVF, 2007, BRAIN RES, V1179, P35, DOI 10.1016/j.brainres.2007.08.043Scheggi S, 2007, J NEUROCHEM, V103, P1168, DOI 10.1111/j.1471-4159.2007.04818.xMa J, 2006, NEUROSCIENCE, V141, P1469, DOI 10.1016/j.neuroscience.2006.05.013Kang UG, 2005, NEUROSCI LETT, V390, P171, DOI 10.1016/j.neulet.2005.08.020Nishi A, 2005, P NATL ACAD SCI USA, V102, P1199, DOI 10.1073/pnas.0409138102SVENNINGSSON P, 2005, AAPS J, V7, pE353Svenningsson P, 2003, SCIENCE, V302, P1412Pozzi L, 2003, J NEUROCHEM, V86, P451, DOI 10.1046/j.1471-4159.2003.01851.xRoh MS, 2003, PROG NEURO-PSYCHOPH, V27, P1Albert KA, 2002, ARCH GEN PSYCHIAT, V59, P705Nishi A, 2002, J NEUROCHEM, V81, P832Svenningsson P, 2002, P NATL ACAD SCI USA, V99, P3188, DOI 10.1073/pnas.052712699Fernandez JJ, 2002, CURR MED CHEM, V9, P229Greengard P, 2001, SCIENCE, V294, P1024JEON SH, 2001, BIOCH BIOPHYSICAL RE, V282, P1025Nath R, 2000, BIOCHEM BIOPH RES CO, V274, P16, DOI 10.1006/bbrc.2000.3070NISHI A, 2000, P NATL ACAD SCI USA, V97, P12940Bibb JA, 1999, NATURE, V402, P669Yui K, 1999, MOL PSYCHIATR, V4, P512Sharma P, 1999, P NATL ACAD SCI USA, V96, P11156Nishi A, 1999, J NEUROCHEM, V72, P2015Yoshida K, 1997, PROG NEURO-PSYCHOPH, V21, P707Jeon SH, 1997, NEUROPHARMACOLOGY, V36, P411DESDOUITS F, 1995, BIOCHEM BIOPH RES CO, V206, P652FOCHTMANN LJ, 1994, PSYCHOPHARMACOL BULL, V30, P321CUMMINGS JL, 1993, J CLIN PSYCHIAT, V54, P14GREENAMYRE JT, 1991, ARCH NEUROL-CHICAGO, V48, P977DIFIGLIA M, 1990, TRENDS NEUROSCI, V13, P286HEMMINGS HC, 1984, J NEUROSCI, V4, P99

Multimodal Characterization of Cardiac Organoids Using Integrations of Pressure-Sensitive Transistor Arrays with Three-Dimensional Liquid Metal Electrodes

Herein, we present an unconventional method for multimodal characterization of three-dimensional cardiac organo-ids. This method can monitor and control the mechanophysio-logical parameters of organoids within a single device. In this method, local pressure distributions of human-induced pluripotent stem-cell-derived cardiac organoids are visualized spatiotemporally by an active-matrix array of pressure-sensitive transistors. This array is integrated with three-dimensional electrodes formed by the high-resolution printing of liquid metal. These liquid-metal electrodes are inserted inside an organoid to form the intra-organoid interface for simultaneous electrophysiological recording and stimulation. The low mechanical modulus and low impedance of the liquid-metal electrodes are compatible with organoids&apos; soft biological tissue, which enables stable electric pacing at low thresholds. In contrast to conventional electrophysiological methods, this measurement of a cardiac organoid&apos;s beating pressures enabled simultaneous treatment of electrical therapeutics using a single device without any interference between the pressure signals and electrical pulses from pacing electrodes, even in wet organoid conditions.11Nsciescopu

High-temperature in situ crystallographic observation of reversible gas sorption in impermeable organic cages

Crystallographic observation of adsorbed gas molecules is a highly difficult task due to their rapid motion. Here, we report the in situ single-crystal and synchrotron powder X-ray observations of reversible CO2 sorption processes in an apparently nonporous organic crystal under varying pressures at high temperatures. The host material is formed by hydrogen bond network between 1,3,5-tris-(4-carboxyphenyl) benzene (H3BTB) and N,N-dimethylformamide (DMF) and by pi-pi stacking between the H3BTB moieties. The material can be viewed as a well-ordered array of cages, which are tight packed with each other so that the cages are inaccessible from outside. Thus, the host is practically nonporous. Despite the absence of permanent pathways connecting the empty cages, they are permeable to CO2 at high temperatures due to thermally activated molecular gating, and the weakly confined CO2 molecules in the cages allow direct detection by in situ single-crystal X-ray diffraction at 323 K. Variable-temperature in situ synchrotron powder X-ray diffraction studies also show that the CO2 sorption is reversible and driven by temperature increase. Solid-state magic angle spinning NMR defines the interactions of CO2 with the organic framework and dynamic motion of CO2 in cages. The reversible sorption is attributed to the dynamic motion of the DMF molecules combined with the axial motions/angular fluctuations of CO2 (a series of transient opening/closing of compartments enabling CO2 molecule passage), as revealed from NMR and simulations. This temperature-driven transient molecular gating can store gaseous molecules in ordered arrays toward unique collective properties and release them for ready useclose