1,937 research outputs found
Hydrodynamic collective effects of active proteins in biological membranes
Lipid bilayers forming biological membranes are known to behave as viscous 2D
fluids on submicrometer scales; usually they contain a large number of active
protein inclusions. Recently, it has been shown [Proc. Nat. Acad. Sci. USA 112,
E3639 (2015)] that such active proteins should in- duce non-thermal fluctuating
lipid flows leading to diffusion enhancement and chemotaxis-like drift for
passive inclusions in biomembranes. Here, a detailed analytical and numerical
investigation of such effects is performed. The attention is focused on the
situations when proteins are concentrated within lipid rafts. We demonstrate
that passive particles tend to become attracted by active rafts and are
accumulated inside them.Comment: 12 pages, 7 figure
Voice Conversion Using Sequence-to-Sequence Learning of Context Posterior Probabilities
Voice conversion (VC) using sequence-to-sequence learning of context
posterior probabilities is proposed. Conventional VC using shared context
posterior probabilities predicts target speech parameters from the context
posterior probabilities estimated from the source speech parameters. Although
conventional VC can be built from non-parallel data, it is difficult to convert
speaker individuality such as phonetic property and speaking rate contained in
the posterior probabilities because the source posterior probabilities are
directly used for predicting target speech parameters. In this work, we assume
that the training data partly include parallel speech data and propose
sequence-to-sequence learning between the source and target posterior
probabilities. The conversion models perform non-linear and variable-length
transformation from the source probability sequence to the target one. Further,
we propose a joint training algorithm for the modules. In contrast to
conventional VC, which separately trains the speech recognition that estimates
posterior probabilities and the speech synthesis that predicts target speech
parameters, our proposed method jointly trains these modules along with the
proposed probability conversion modules. Experimental results demonstrate that
our approach outperforms the conventional VC.Comment: Accepted to INTERSPEECH 201
Blow-up for Semilinear Wave Equations with a Data of the Critical Decay having a Small Loss
It is known that we have a global existence for wave
equations with super-critical nonlinearities when the data has a
critical decay of powers. In this paper, we will see that a blow-up
result can be established if the data decays like the critical power
with a small loss such as any logarithmic power. This means that
there is no relation between the critical decay of the initial data
and the integrability of the weight, while the critical power of the
nonlinearity is closely related to the integrability. The critical
decay of the initial data is determined only by scaling invariance
of the equation. We also discuss a nonexistence of local in time
solutions for the initial data increasing at infinity
Anomalous diffusion and transport by a reciprocal convective flow
Under low-Reynolds-number conditions, dynamics of convection and diffusion
are usually considered separately because their dominant spatial and temporal
scales are different, but cooperative effects of convection and diffusion can
cause diffusion enhancement [Koyano et al., Phys. Rev. E, 102, 033109 (2020)].
In this study, such cooperative effects are investigated in detail. Numerical
simulations based on the convection-diffusion equation revealed that
anisotropic diffusion and net shift as well as diffusion enhancement occur
under a reciprocal flow. Such anomalous diffusion and transport are
theoretically derived by the analyses of the Langevin dynamics.Comment: 10 pages, 9 figure
Fibroblast heterogeneity and tertiary lymphoid tissues in the kidney
Fibroblasts reside in various organs and support tissue structure and homeostasis under physiological conditions. Phenotypic alterations of fibroblasts underlie the development of diverse pathological conditions, including organ fibrosis. Recent advances in single-cell biology have revealed that fibroblasts comprise heterogeneous subpopulations with distinct phenotypes, which exert both beneficial and detrimental effects on the host organs in a context-dependent manner. In the kidney, phenotypic alterations of resident fibroblasts provoke common pathological conditions of chronic kidney disease (CKD), such as renal anemia and peritubular capillary loss. Additionally, in aged injured kidneys, fibroblasts provide functional and structural supports for tertiary lymphoid tissues (TLTs), which serve as the ectopic site of acquired immune reactions in various clinical contexts. TLTs are closely associated with aging and CKD progression, and the developmental stages of TLTs reflect the severity of renal injury. In this review, we describe the current understanding of fibroblast heterogeneity both under physiological and pathological conditions, with special emphasis on fibroblast contribution to TLT formation in the kidney. Dissecting the heterogeneous characteristics of fibroblasts will provide a promising therapeutic option for fibroblast-related pathological conditions, including TLT formation
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