Notes

Within vivo bioresorbability and also bone creation capacity associated with sintered extremely pure calcium supplement carbonate granules.
We use a simple model of electronic excitations to argue that this multiphonon signal will also accompany ionization signals induced from DM-electron scattering or the Migdal effect. In well-motivated models where DM couples to a heavy, kinetically mixed dark photon, we show that these signals can probe experimental milestones for cosmological DM production via thermal freeze-out, including the thermal target for Majorana fermion DM.A long-standing mystery of fundamental importance in correlated electron physics is to understand strange non-Fermi liquid metals that are seen in diverse quantum materials. A striking experimental feature of these metals is a resistivity that is linear in temperature (T). In this Letter we ask what it takes to obtain such non-Fermi liquid physics down to zero temperature in a translation invariant metal. If in addition the full frequency (ω) dependent conductivity satisfies ω/T scaling, we argue that the T-linear resistivity must come from the intrinsic physics of the low energy fixed point. Combining with earlier arguments that compressible translation invariant metals are "ersatz Fermi liquids" with an infinite number of emergent conserved quantities, we obtain powerful and practical conclusions. We show that there is necessarily a diverging susceptibility for an operator that is odd under inversion and time reversal symmetries, and has zero crystal momentum. We discuss a few other experimental consequences of our arguments, as well as potential loopholes, which necessarily imply other exotic phenomena.In this Letter, a water-in-oil swimming droplet's transition from straight to curvilinear motion is investigated experimentally and theoretically. An analysis of the experimental results and the model reveal that the motion transition depends on the susceptibility of the droplet's direction of movement to external stimuli as a function of environmental parameters such as droplet size. The simplicity of the present experimental system and the model suggests implications for a general class of transitions in self-propelled swimmers.The appearance of surface distortions on polymer melt extrudates, often referred to as sharkskin instability, is a long-standing problem. We report results of a simple physical model, which link the inception of surface defects with intense stretch of polymer chains and subsequent recoil at the region where the melt detaches from the solid wall of the die. The transition from smooth to wavy extrudate is attributed to a Hopf bifurcation, followed by a sequence of period doubling bifurcations, which eventually lead to elastic turbulence under creeping flow. The predicted flow profiles exhibit all the characteristics of the experimentally observed surface defects during polymer melt extrusion.In a closed system, it is well known that the time-reversal symmetry can lead to Kramers degeneracy and protect nontrivial topological states such as the quantum spin Hall insulator. In this Letter, we address the issue of whether these effects are stable against coupling to the environment, provided that both the environment and the coupling to the environment also respect time-reversal symmetry. By employing a non-Hermitian Hamiltonian with the Langevin noise term and utilizing the non-Hermitian linear response theory, we show that the spectral functions for Kramers degenerate states can be split by dissipation, and the backscattering between counterpropagating edge states can be induced by dissipation. The latter leads to the absence of accurate quantization of conductance in the case of the quantum spin Hall effect. As an example, we demonstrate this concretely with the Kane-Mele model. Our study can also include interacting topological phases protected by time-reversal symmetry.According to Landau's Fermi liquid theory, the main properties of the quasiparticle excitations of an electron gas are embodied in the effective mass m^*, which determines the energy of a single quasiparticle, and the Landau interaction function, which indicates how the energy of a quasiparticle is modified by the presence of other quasiparticles. This simple paradigm underlies most of our current understanding of the physical and chemical behavior of metallic systems. The quasiparticle effective mass of the three-dimensional homogeneous electron gas has been the subject of theoretical controversy, and there is a lack of experimental data. In this Letter, we deploy diffusion Monte Carlo (DMC) methods to calculate m^* as a function of density for paramagnetic and ferromagnetic three-dimensional homogeneous electron gases. The DMC results indicate that m^* decreases when the density is reduced, especially in the ferromagnetic case. The DMC quasiparticle energy bands exclude the possibility of a reduction in the occupied bandwidth relative to that of the free-electron model at density parameter r_s=4, which corresponds to Na metal.The study of liquid-liquid phase transitions has attracted considerable attention. One interesting example of this phenomenon is phosphorus, for which the existence of a first-order phase transition between a low density insulating molecular phase and a conducting polymeric phase has been experimentally established. In this Letter, we model this transition by an ab initio quality molecular dynamics simulation and explore a large portion of the liquid section of the phase diagram. We draw the liquid-liquid coexistence curve and determine that it terminates into a second-order critical point. Close to the critical point, large coupled structure and electronic structure fluctuations are observed.There are different kinds of molecular chirality, such as zero-dimensional point chirality, one-dimensional axial chirality, 2D planar chirality, and 3D chirality. When they coexist in one system, such as in helical structures of proteins and DNA, they form a chirality hierarchy. Earlier, we showed that the chirality propensity of a lower level in a hierarchy is dictated by that of a higher level and henceforth proposed the Principle of Chirality Hierarchy. In this work, we confirm the validity of this principle in the three-blade propeller molecular system. Our results show that the preference of the 0D chirality of a functional group in the propeller system is determined by the 1D chirality, and homochirality is also a remarkable feature for this system. The establishment and confirmation of the Principle of Chirality Hierarchy from this work should find important applications in asymmetric synthesis, macromolecular assembly, and many others.New methods for C-N bond construction exploiting the N-centered electrophilic character of iminoquinones are reported. Iminoquinones, generated in situ via the condensation of o-vinylanilines with benzoquinones, undergo acid-catalyzed cyclization to afford N-arylindoles in excellent yields. Under similar reaction conditions, homoallylic amines react analogously to afford N-arylpyrroles. Additionally, organometallic nucleophiles are shown to add to the nitrogen atom of N-alkyliminoquinones to provide amine products. Finally, iminoquinones are shown to be competent electrophiles for copper-catalyzed hydroamination.Enantioenriched allenes are important building blocks. While they have been accessed by other coupling methodologies, enantioenriched allenes have been rarely obtained via C-H activation. In this work, kinetic resolution of tertiary propargyl alcohols as an allenylating reagent has been realized via rhodium(III)-catalyzed C-H allenylation of benzamides. The reaction proceeded efficiently under mild conditions, and both the allenylated products and the propargyl alcohols were obtained in high enantioselectivities with an s-factor of up to 139. Poly(vinyl alcohol) datasheet The resolution results from bias of the two propargylic substituents and is assisted by a chiral zinc carboxylate additive.The nature of donor-acceptor interactions is important for the understanding of dative bonding and can provide vital insights into many chemical processes. Here, we have performed a computational study to elucidate substantial differences between different types of dative interactions. For this purpose, a data set of 20 molecular complexes stabilized by dative bonds was developed (DAT20). A benchmark study that considers many popular density functionals with respect to accurate quantum chemical interaction energies and geometries revealed two different trends between the complexes of DAT20. This behavior was further explored by means of frontier molecular orbitals, extended-transition-state natural orbitals for chemical valence (ETS-NOCV), and natural energy decomposition analysis (NEDA). These methods revealed the extent of the forward and backdonation between the donor and acceptor molecules and how they influence the total interaction energies and molecular geometries. A new classification of dative bonds is suggested.The synthesis of metallic transition metal nitrides (TMNs) has traditionally been performed under harsh conditions, which makes it difficult to prepare TMNs with high surface area and porosity due to the grain sintering. Herein, we report a general and rapid (30 s) microwave synthesis method for preparing TMNs with high specific surface area (122.6-141.7 m2 g-1) and porosity (0.29-0.34 cm3 g-1). Novel single-crystal porous WN, Mo2N, and V2N are first prepared by this method, which exhibits strong surface plasmon resonance, photothermal conversion, and surface-enhanced Raman scattering effects. Different from the conventional low-temperature microwave absorbing media such as water and polymers, as new concept absorbing media, hydrated metal oxides and metallic metal oxides are found to have a remarkable high-temperature microwave heating effect and play key roles in the formation of TMNs. The current research results provide a new-concept microwave method for preparing high lattice energy compounds with high specific surface.Surface modifications for easy removal of liquids and solids from various metal surfaces are much less established than for silicon (Si) or glass substrates. Trimethylsiloxy-terminated polymethylhydrosiloxane (PMHS) is very promising because it can be directly immobilized covalently to a wide variety of metal surfaces by simply heating neat PMHS liquid, resulting in a film showing excellent dynamic omniphobicity. However, such PMHS films are easily degraded by hydrolytic attack in an aqueous environment. In this study, we have successfully improved the hydrolytic stability of the PMHS-covered ultrasmooth metal (Ti, Al, Cr, Ni, and Cu) surfaces by end-capping of the residual Si-H groups of the PMHS films with vinyl-terminated organosilanes, for example, trimethylvinylsilane (TMVS), through a platinum-catalyzed hydrosilylation reaction. The resulting TMVS-capped PMHS film surfaces showed significantly greater stability even after submersion in water for 6 days, with their excellent dynamic dewetting behavior toward water, toluene, n-hexadecane, and ethanol changing little. In addition, they also showed reasonable anti-icing (icephobic) properties with low ice-adhesion strength of less than 50 kPa even after 20 cycles of testing at -15 °C.Understanding the effects of soluble impurities or suspended particles on ice growth is of significant importance from Earth science to materials engineering. Ions are common impurities with ice in a wide range of fields, but their effects on ice growth remain largely elusive. Here, we studied the ion-specific effects on single ice crystal growth in various electrolyte and polyelectrolyte solutions and found F- and NH4+ show remarkable abilities of inducing single ice crystals to form hexagonal shapes and reducing the growth rates of ice crystals. Molecular dynamics simulations reveal the accumulation of F- around the ice/solution interface that plays a key role in the shapes and growth rates of single ice crystals. The understanding of ion-specific effects on ice growth opens up more possibilities for improving related fields, e.g., freeze desalination and cryopreservation.
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