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Bo Zheng, Wenliang Guo, Linchao Hu, Mugen Huang, Jianshe Yu
Dengue, malaria, and Zika are dangerous diseases primarily transmitted by Aedes aegypti, Aedes albopictus, and Anopheles stephensi. In the last few years, a new disease control method, besides pesticide spraying to kill mosquitoes, has been developed by releasing mosquitoes carrying bacterium Wolbachia into the natural areas to infect the wild population of mosquitoes and block disease transmission. The bacterium is transmitted by infected mothers and the maternal transmission was assumed to be perfect in virtually all previous models...
April 1, 2018: Mathematical Biosciences and Engineering: MBE
Bashar Ibrahim
The precise regulation of cell life division is indispensable to the reliable inheritance of genetic material, i.e. DNA, in successive generations of cells. This is governed by dedicated biochemical networks which ensure that all requirements are met before transition from one phase to the next. The Spindle Assembly Checkpoint (SAC) is an evolutionarily mechanism that delays mitotic progression until all chromosomes are properly linked to the mitotic spindle. During some asymmetric cell divisions, such as those observed in budding yeast, an additional mechanism, the Spindle Position Checkpoint (SPOC), is required to delay exit from mitosis until the mitotic spindle is correctly aligned...
April 1, 2018: Mathematical Biosciences and Engineering: MBE
Giacomo Mariani, Antoine Goujon, Emilie Moulin, Michel Rawiso, Nicolas Giuseppone, Eric Buhler
In this article, the dynamic structure of complex supramolecular polymers composed of bistable [c2]daisy chain rotaxanes as molecular machines that are linked by ureidopyrimidinones (Upy) as recognition moieties was studied. pH actuation of the integrated mechanically active rotaxanes controls the contraction/extension of the polymer chains as well as their physical reticulation. Small-angle neutron and X-ray scattering were used to study in-depth the nanostructure of the contracted and extended polymer aggregates in toluene solution...
November 21, 2017: Nanoscale
Stefan Albert, Katharina Schmack, Philipp Sterzer, Gaby Schneider
Viewing of ambiguous stimuli can lead to bistable perception alternating between the possible percepts. During continuous presentation of ambiguous stimuli, percept changes occur as single events, whereas during intermittent presentation of ambiguous stimuli, percept changes occur at more or less regular intervals either as single events or bursts. Response patterns can be highly variable and have been reported to show systematic differences between patients with schizophrenia and healthy controls. Existing models of bistable perception often use detailed assumptions and large parameter sets which make parameter estimation challenging...
November 20, 2017: PLoS Computational Biology
Jean-Baptiste Lugagne, Sebastián Sosa Carrillo, Melanie Kirch, Agnes Köhler, Gregory Batt, Pascal Hersen
Cybergenetics is a novel field of research aiming at remotely pilot cellular processes in real-time with to leverage the biotechnological potential of synthetic biology. Yet, the control of only a small number of genetic circuits has been tested so far. Here we investigate the control of multistable gene regulatory networks, which are ubiquitously found in nature and play critical roles in cell differentiation and decision-making. Using an in silico feedback control loop, we demonstrate that a bistable genetic toggle switch can be dynamically maintained near its unstable equilibrium position for extended periods of time...
November 17, 2017: Nature Communications
Cunming Liu, Jianxin Zhang, Latévi Max Lawson Daku, David J Gosztola, Sophie Canton, Xiaoyi Zhang
Investigating the photoinduced electronic and structural response of bistable molecular building blocks incorporating transition metals in solution phase constitutes a necessary stepping stone for steering their properties towards applications and perfomance optimizations. This work presents a detailed X-ray transient absorption (XTA) spectroscopy study of a prototypical spin crossover (SCO) complex [Fe(II)(mbpy)3](2+) (where mbpy=4,4'-dimethyl-2,2'-bipyridine) with a [Fe(II)N6] first coordination shell, in water (H2O) and acetonitrile (CH3CN)...
November 10, 2017: Journal of the American Chemical Society
Valentina Bleve, Paola Franchi, Evangelia Konstanteli, Lorenzo Gualandi, Stephen M Goldup, Elisabetta Mezzina, Marco Lucarini
The synthesis of a new nitroxide crown ether (8) and its use as the wheel in a bistable [2]rotaxane containing dialkylammonium and 4,4`-bipyridinium recognition sites, is reported. The synthesis of 8 was achieved by the sequential addition of substituted phenyl groups to nitrone derivatives leading to the preferential formation of the cis stereoisomer. Due to charge-dipolar interactions between the nitroxide unit and bipyridinium moiety, it was possible to probe the movement of the macrocycle between the two molecular stations of the [2]rotaxane after addition of a base by measuring the nitrogen hyperfine splittings in the corresponding EPR spectra...
November 10, 2017: Chemistry: a European Journal
Antonio A García-Valdivia, Jose M Seco, Javier Cepeda, Antonio Rodríguez-Diéguez
Detailed structural, magnetic, and photoluminescence (PL) characterization of four new compounds based on 1-methylimidazole-5-carboxylate (mimc) ligand and transition metal ions, namely [Ni(mimc)2(H2O)4] (1), [Co(μ-mimc)2]n (2), {[Cu2(μ-mimc)4(H2O)]·2H2O}n (3), and [Cd(μ-mimc)2(H2O)]n (4) is reported. The structural diversity found in the family of compounds derives from the coordination versatility of the ligand, which coordinates as a terminal ligand to give a supramolecular network of monomeric entities in 1 or acts as a bridging linker to build isoreticular 2D coordination polymers (CPs) in 2-4...
November 9, 2017: Inorganic Chemistry
Gang Zhao, Dagmar Wirth, Ingo Schmitz, Michael Meyer-Hermann
Physiological insulin secretion exhibits various temporal patterns, the dysregulation of which is involved in diabetes development. We analyzed the impact of first-phase and pulsatile insulin release on glucose and lipid control with various hepatic insulin signaling networks. The mathematical model suggests that atypical protein kinase C (aPKC) undergoes a bistable switch-on and switch-off, under the control of insulin receptor substrate 2 (IRS2). The activation of IRS1 and IRS2 is temporally separated due to the inhibition of IRS1 by aPKC...
November 8, 2017: Nature Communications
Chongqin Zhu, Yurui Gao, Yingying Huang, Hui Li, Sheng Meng, Joseph S Francisco, Xiao Cheng Zeng
Surfaces that exhibit both superhydrophobic and superoleophobic properties have recently been demonstrated. Specifically, remarkable designs based on overhanging/inverse-trapezoidal microstructures enable water droplets to contact these surfaces only at the tips of the micro-pillars, in a state known as the Cassie state. However, the Cassie state may transition into the undesirable Wenzel state under certain conditions. Herein, we show from large-scale molecular dynamics simulations that the transition between the Cassie and Wenzel states can be controlled via precisely designed trapezoidal nanostructures on a surface...
November 6, 2017: Nanoscale
A Quesada, R Gargallo-Caballero, Y Montaña, M Foerster, L Aballe, J F Fernández, J de la Figuera
High aspect-ratio Fe nanostrips are known to reversibly switch from a single-domain magnetic state to a multidomain diamond pattern as a function of temperature (T) and width. This magnetic bistability can be understood by the temperature-dependent balance between magnetocrystalline, shape and magnetoelastic anisotropies and has potential applications in magnetic logic devices. However, as Fe nanostructures easily oxidize, protecting the surface with capping layers may be required, which could largely affect the anisotropy balance...
October 24, 2017: Ultramicroscopy
P Malgaretti, I Pagonabarraga, J-F Joanny
We analyze the collective behavior of hydrodynamically coupled molecular motors. We show that the local fluxes induced by motor displacement can induce the experimentally observed bidirectional motion of cargoes and vesicles. By means of a mean-field approach we show that sustained oscillations as well as bistable collective motor motion arise even for very large collection of motors, when thermal noise is irrelevant. The analysis clarifies the physical mechanisms responsible for such dynamics by identifying the relevant coupling parameter and its dependence on the geometry of the hydrodynamic coupling as well as on system size...
October 20, 2017: Physical Review Letters
Augustine Kshetrimayum, Hendrik Weimer, Román Orús
Understanding dissipation in 2D quantum many-body systems is an open challenge which has proven remarkably difficult. Here we show how numerical simulations for this problem are possible by means of a tensor network algorithm that approximates steady states of 2D quantum lattice dissipative systems in the thermodynamic limit. Our method is based on the intuition that strong dissipation kills quantum entanglement before it gets too large to handle. We test its validity by simulating a dissipative quantum Ising model, relevant for dissipative systems of interacting Rydberg atoms, and benchmark our simulations with a variational algorithm based on product and correlated states...
November 3, 2017: Nature Communications
Anja Poblotzki, Hannes C Gottschalk, Martin A Suhm
Intermolecular energy balances are supramolecular complexes with a nearly degenerate bistable docking structure and low barriers in between, which can be tuned by chemical substitution to prefer one or the other site. The docking preference can be probed by forming the complexes in a supersonic jet expansion and by measuring their spectroscopic signature. Linear spectroscopies are shown to be well suited for this purpose, in particular when they are assisted by more sensitive techniques and by approximate computed photon interaction cross sections...
November 8, 2017: Journal of Physical Chemistry Letters
Davood Mousanezhad, Soroush Kamrava, Ashkan Vaziri
Origami, widely known as the ancient Japanese art of paper folding, has recently inspired a new paradigm of design for mechanical metamaterials and deployable structural systems. However, lack of rationalized design guidelines and scalable manufacturing methods has hindered their applications. To address this limitation, we present analytical methods for designing origami-based closed-loop units with inherent foldability, and for predicting their folding response (e.g., folding force, bistability, and area and volume change by folding)...
November 1, 2017: Scientific Reports
Ishant Tiwari, Darshil Dave, Richa Phogat, Neev Khera, P Parmananda
Periodic and Aperiodic Stochastic Resonance (SR) and Deterministic Resonance (DR) are studied in this paper. To check for the ubiquitousness of the phenomena, two unrelated systems, namely, FitzHugh-Nagumo and a particle in a bistable potential well, are studied. Instead of the conventional scenario of noise amplitude (in the case of SR) or chaotic signal amplitude (in the case of DR) variation, a tunable system parameter ("a" in the case of FitzHugh-Nagumo model and the damping coefficient "j" in the bistable model) is regulated...
October 2017: Chaos
Robert G Endres
Far-from-equilibrium thermodynamics underpins the emergence of life, but how has been a long-outstanding puzzle. Best candidate theories based on the maximum entropy production principle could not be unequivocally proven, in part due to complicated physics, unintuitive stochastic thermodynamics, and the existence of alternative theories such as the minimum entropy production principle. Here, we use a simple, analytically solvable, one-dimensional bistable chemical system to demonstrate the validity of the maximum entropy production principle...
October 31, 2017: Scientific Reports
C M McLeod, R L Mauck
Mesenchymal stem cells (MSCs) display substantial cell-to-cell variation. This heterogeneity manifests among donors, among tissue sources, and within cell populations. Such pervasive variability complicates the use of MSCs in regenerative applications and may limit their therapeutic efficacy. Most conventional assays measure MSC properties in bulk and, as a consequence, mask this cell-to-cell variation. Recent studies have identified extensive variability amongst and within clonal MSC populations, in dimensions including functional differentiation capacity, molecular state (e...
October 27, 2017: European Cells & Materials
Anshou Zheng, Guangyong Zhang, Hongyun Chen, Tingting Mei, Jibing Liu
We propose a scheme for nonreciprocal light propagation in two coupled cavities system, in which a two-level quantum emitter is coupled to one of the optical microcavities. For the case of parity-time ([Formula: see text]) symmetric system (i.e., coupled active-passive cavities system), the cavity gain can significantly enhance the optical nonlinearity induced by the interaction between a quantum emitter and cavity field beyond weak-excitation approximation. The increased optical nonlinearity results in the non-lossy nonreciprocal light propagation with high isolation ratio in proper parameters range...
October 25, 2017: Scientific Reports
Souleymane Kamara, Quang-Hung Tran, Vincent Davesne, Gautier Félix, Lionel Salmon, Kunwoo Kim, CheolGi Kim, Azzedine Bousseksou, Ferial Terki
A promising and original method to study the spin-transition in bistable spin-crossover (SCO) materials using a magnetoresistive multiring sensor and its self-generated magnetic field is reported. Qualitative and quantitative studies are carried out combining theoretical and experimental approaches. The results show that only a small part of matter dropped on the sensor surface is probed by the device. At a low bias-current range, the number of detected nanoparticles depends on the amplitude of the current...
October 25, 2017: Advanced Materials
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