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Lithium supply shortages have prompted the search for alternatives to widespread grid system applications. Potassium-ion batteries (PIBs) have emerged to promising candidates for this purpose. Nonetheless, the large radius of K+ (1.38 Å) impedes the march of satisfactory cathode materials. Here, we used solid-phase synthesis to prepare a layered K0.37MnO2·0.25H2O (KMO) cathode, comprising alternately connected MnO6 octahedra with a large interlayer spacing (0.71 nm) to accommodate the migration and transport of K+ ions. The cathode material achieved initial specific capacities of 102.3 and 88.1 mA h g−1 at current densities of 60 mA g−1 and 1 A g−1, respectively. The storage mechanism of K+ ions in PIBs was demonstrated ex situ using x-ray diffraction, x-ray photoelectron spectroscopy, and Raman spectroscopy measurements. Overall, our proposed KMO was confirmed as an auspicious cathode material for potential use in PIBs.

Extrusible biomaterials have recently attracted increasing attention due to the desirable injectability and printability to allow minimally invasive administration and precise construction of tissue mimics. Specifically, self-healing colloidal gels are a novel class of candidate materials as injectables or printable inks considering their fascinating viscoelastic behavior and high degree of freedom on tailoring their compositional and mechanical properties. Herein, we developed a novel class of adaptable and osteogenic composite colloidal gels via electrostatic assembly of gelatin nanoparticles and nanoclay particles. These composite gels exhibited excellent injectability and printability, and remarkable mechanical properties reflected by the maximal elastic modulus reaching ∼150 kPa combined with high self-healing efficiency, outperforming most previously reported self-healing hydrogels. Moreover, the cytocompatibility and the osteogenic capacity of the colloidal gels were demonstrated by inductive culture of MC3T3 cells seeded on the three-dimensional (3D)-printed colloidal scaffolds. Besides, the biocompatibility and biodegradability of the colloidal gels was proved in vivo by subcutaneous implantation of the 3D-printed scaffolds. Furthermore, we investigated the therapeutic capacity of the colloidal gels, either in form of injectable gels or 3D-printed bone substitutes, using rat sinus bone augmentation model or critical-sized cranial defect model. The results confirmed that the composite gels were able to adapt to the local complexity including irregular or customized defect shapes and continuous on-site mechanical stimuli, but also to realize osteointegrity with the surrounding bone tissues and eventually be replaced by newly formed bones.

The correlation between the optical Kerr effect (OKE) spectroscopy of supercooled water at ambient pressure and its structural tetrahedrality was investigated by contrasting simulation results of two non-polarizable water models modified with the same collective polarizability, which involves intrinsic molecular polarizability and induced polarizability arising from interactions between molecular dipoles. The tetrahedrality of water structure was typified with the second-peak maximum in the pair distribution function of oxygens and the fraction of molecules, which and their neighbours up to the second hydration shell all have four H-bond coordinators. Our results indicate that the intermolecular vibrational band in the OKE spectrum of supercooled water is considerably correlated to its structural tetrahedrality.

Embryogenesis is a spatio-temporal multicellular evolutional process involved with intracellular biochemical activities and intercellular biophysical interactions. Reproducible and precise multicellular structures contribute to robustness of embryonic development by cell-cell communication, morphogenesis and other significant biological events. Using Caenorhabditis elegans as animal model, recently several researches established mechanical models to reconstruct the multicellular structures of this developmental system, in which cells interact via repulsive or attractive potentials inside an ellipsoidal eggshell. However, those models ignored some practical details and lack of test in depth. In this paper, we improved an in silico modeling framework based on previous models by revising formulae of interactive force and applying in vivo experimental information of eggshell shape, cell volume, cell position and cell-cell connection relationship. Cell pairs with and without empirically repeated connection were regarded to have different types of attractive force, which could help stabilize cells into their experimentally observed locations accompanied by correct neighbour relationships. Both previous models and our revised ones were tested, verified and compared to each other. Our modeling framework not only reproduces the multicellular structure patterns in an artificially compressed embryo with ∼50 cells, but also exhibits a potential to uncover active adjustments and controls on cell positioning.

We introduce a surface growth model where the elementary events are characterized by a waiting time distribution P(T). Exact relations to directed polymer statistics and to continuous time random walk problems are established. For P(T) - I/.’“ the behaviour is similar to that of the Zhang model where rare-event-dominated kinetic roughening occurs due to a power-law noise in the surface increments. A careful correction to scaling analysis of our numerical results in 1 + 1 dimensions indicates universality with the Zhang model for fixed values of p.

The ability to monitor nutrient and other environmental conditions with high sensitivity is crucial for cell growth and survival. Sensory adaptation allows a cell to recover its sensitivity after a transient response to a shift in the strength of extracellular stimulus. The working principles of adaptation have been established previously based on rate equations which do not consider fluctuations in a thermal environment. Recently, Lan et al (2012 Nat. Phys. 8 422–8) performed a detailed analysis of a stochastic model for the Escherichia coli sensory network. They showed that accurate adaptation is possible only when the system operates in a nonequilibrium steady-state (NESS). They further proposed an energy-speed-accuracy (ESA) trade-off relation. We present here analytic results on the NESS of the model through a mapping to a one-dimensional birth-death process. An exact expression for the entropy production rate is also derived. Based on these results, we are able to discuss the ESA relation in a more general setting. Our study suggests that the adaptation error can be reduced exponentially as the methylation range increases. Finally, we show that a nonequilibrium phase transition exists in the infinite methylation range limit, despite the fact that the model contains only two discrete variables.

Thermally driven diffusive motion of a particle underlies many physical and biological processes. In the presence of traps and obstacles, the spread of the particle is substantially impeded, leading to subdiffusive scaling at long times. The statistical mechanical treatment of diffusion in a disordered environment is often quite involved. In this short review, we present a simple and unified view of the many quantitative results on anomalous diffusion in the literature, including the scaling of the diffusion front and the mean first-passage time. Various analytic calculations and physical arguments are examined to highlight the role of dimensionality, energy landscape, and rare events in affecting the particle trajectory statistics. The general understanding that emerges will aid the interpretation of relevant experimental and simulation results.

Bi, Tm singly doped and Bi/Tm co-doped glasses with molar compositions of 60SiO2–20Ga2O3–15Na2O–5Al2O3 were prepared by the conventional melt-quenching method. The enhanced emission of the Tm3+:3H4→3F4 transition at 1470 nm, and the quenched emission of the Tm3+:3F4→3H6 transition at 1860 nm were observed for Bi/Tm co-doped silicate glasses under 808 nm excitation. For 980 nm excitation, no Tm-related emission was observed for Tm singly doped glasses, while the emission of the Tm3+:3F4→3H6 transition at 1860 nm was observed for Bi/Tm co-doped glasses. These results indicated that the energy transfer occurred between active Bi ions and Tm3+ in Bi/Tm co-doped silicate glasses, in which the energy corresponding to the Bi-related emission level excited the Tm3+ from 3H6 to the 3H5 level under 980 nm excitation, and from 3F4 to the 3H4 level under 808 nm excitation. The energy-transfer processes were studied on the basis of the Inokuti–Hirayama model, and the energy transfer of the electric dipole–dipole interaction was confirmed to be dominant in Bi/Tm co-doped glasses. The Bi/Tm co-doped silicate glasses may be potential materials for producing broadband optical fiber amplifiers and tunable lasers.

The entrainment transition of coupled random frequency oscillators presents a long-standing problem in nonlinear physics. The onset of entrainment in populations of large but finite size exhibits strong sensitivity to fluctuations in the oscillator density at the synchronizing frequency. This is the source for the unusual values assumed by the correlation size exponent $��'$. Locally coupled oscillators on a $d$-dimensional lattice exhibit two types of frequency entrainment: symmetry-breaking at $d > 4$, and aggregation of compact synchronized domains in three and four dimensions. Various critical properties of the transition are well captured by finite-size scaling relations with simple yet unconventional exponent values., 9 pages, 1 figure, to appear in a special issue of JSTAT dedicated to Statphys24