Ecological and genomic profiling of anaerobic methane-oxidizing archaea in a deep granitic environment.

Recent single-gene-based surveys of deep continental aquifers demonstrated the widespread occurrence of archaea related to Candidatus Methanoperedens nitroreducens (ANME-2d) known to mediate anaerobic oxidation of methane (AOM). However, it is unclear whether ANME-2d mediates AOM in the deep continental biosphere. In this study, we found the dominance of ANME-2d in groundwater enriched in sulfate and methane from a 300-m deep underground borehole in granitic rock.

Grain-scale stable carbon and oxygen isotopic variations of the international reference calcite, IAEA-603.

Rationale: The new international reference material IAEA-603 (calcite) for stable carbon and oxygen isotopes (δ C and δ O values) was released in 2016 to replace the previous reference material, NBS19 (exhausted). We examined the grain-scale isotopic variations in IAEA-603 for application to microscale isotopic analysis of carbonate samples.

Methods: Individual grains of IAEA-603 were analyzed with an IsoPrime100 isotope ratio mass spectrometer with a customized continuous-flow gas preparation system (MICAL3c).

J-shaped stress-strain diagram of collagen fibers: Frame tension of triangulated surfaces with fixed boundaries.

We present Monte Carlo data of the stress-strain diagrams obtained using two different triangulated surface models. The first is the canonical surface model of Helfrich and Polyakov (HP), and the second is a Finsler geometry (FG) model. The shape of the experimentally observed stress-strain diagram is called J-shaped.

Finsler Geometry Modeling of Phase Separation in Multi-Component Membranes.

A Finsler geometric surface model is studied as a coarse-grained model for membranes of three components, such as zwitterionic phospholipid (DOPC), lipid (DPPC) and an organic molecule (cholesterol). To understand the phase separation of liquid-ordered (DPPC rich) L o and liquid-disordered (DOPC rich) L d , we introduce a binary variable σ ( = ± 1 ) into the triangulated surface model. We numerically determine that two circular and stripe domains appear on the surface.

Formation and Geological Sequestration of Uranium Nanoparticles in Deep Granitic Aquifer.

The stimulation of bacterial activities that convert hexavalent uranium, U(VI), to tetravalent uranium, U(IV), appears to be feasible for cost-effective remediation of contaminated aquifers. However, U(VI) reduction typically results in the precipitation of U(IV) particles less than 5 nanometers in diameter, except for environmental conditions enriched with iron. Because these tiny particles are mobile and susceptible to oxidative dissolution after the termination of nutrient injection, in situ bioremediation remains to be impractical.

Method and apparatus for characterization of electric field-induced aggregation in pre-crystalline protein solutions.

The article presents a method and an apparatus for the characterization of protein aggregation under an applied internal electric field. The method is based on a forward light scattering technique that is highly sensitive to aggregates in pre-crystalline protein solutions. Transparent conductive films are used as electrodes for a planar thin sample cell, which enables precise measurement of the forward light scattering at small angles through the electrodes.

First-order phase transition in the tethered surface model on a sphere.

We show that the tethered surface model of Helfrich and Polyakov-Kleinert undergoes a first-order phase transition separating the smooth phase from the crumpled one. The model is investigated by the canonical Monte Carlo simulations on spherical and fixed connectivity surfaces of size up to N = 15 212. The first-order transition is observed when N > 7000, which is larger than those in previous numerical studies, and a continuous transition can also be observed on the smaller surfaces.

Phase transitions of a tethered surface model with a deficit angle term.

The Nambu-Goto model is investigated by using the canonical Monte Carlo simulations on fixed connectivity surfaces of spherical topology. Three distinct phases are found: crumpled, tubular, and smooth. The crumpled and the tubular phases are smoothly connected, and the tubular and the smooth phases are connected by a discontinuous transition.

First-order phase transition of fixed connectivity surfaces.

We report numerical evidence of the discontinuous transition of a tethered membrane model which is defined within a framework of the membrane elasticity of Helfrich. Two kinds of phantom tethered membrane models are studied via the canonical Monte Carlo simulation on triangulated fixed connectivity surfaces of spherical topology. One surface model is defined by the Gaussian term and the bending energy term, and the other, which is tensionless, is defined by the bending energy term and a hard wall potential.

Monte Carlo simulations of branched polymer surfaces without bending elasticity.

We study a model of elastic surfaces that was first constructed by Baillie et al. for an interpolation between the models of fluid and crystalline membranes. The Hamiltonian of the model is a linear combination of the Gaussian energy and a squared scalar curvature energy.