Immunolocalization patterns of histone-deacetylases in salivary glands of mice during postnatal development.

Objective: Histone-deacetylases (HDACs) are epigenetic modulators involved in the control of gene expression. No data are available on the expression or subcellular localization of HDACs in salivary glands. The present study aims to examine the subcellular distribution of HDACs in salivary glands during postnatal development.

Stimulus-Responsive Lanthanide MOF Materials Encapsulated with Viologen Derivatives: Characterization, Photophysical Properties and Sensing on Nitrophenols.

Viologens (1,1'-disubstituted 4,4'-bipyridyls) possessing electron-deficient properties and redox activity are a class of suitable chromophores to assemble metal-organic hybrid photochromic materials. Thus, viologen-functionalized metal-organic frameworks (MOFs) have attracted much attention for their photochromic properties; however, the syntheses of lanthanide-viologen hybrid crystalline photochromic materials still face many challenges. For example, the structures and properties of the final products are difficult to predict and are limited by molecular configurations.

Fabrication of a TiO/FeO Core/Shell Nanostructure by Pulse Laser Deposition toward Stable and Visible Light Photoelectrochemical Water Splitting.

Here, we report the fabrication of TiO/FeO core/shell heterojunction nanorod arrays by a pulsed laser deposition (PLD) process and their further use as photoelectrodes toward high-performance visible light photoelectrochemical (PEC) water splitting. The morphology, phase, and carrier conduction mechanism of plain TiO and TiO/FeO core/shell nanostructure were systematically investigated. PEC measurements show that the TiO/FeO core/shell nanostructure enhances photocurrent density by nearly 2 times than the plain ones, increases visible light absorption from 400 to 550 nm, raises the on/off separation rate, and delivers high stability with only a 3% decrease of current density for tests of even more than 14 days.

Transport of self-propelled particles across a porous medium: trapping, clogging, and the Matthew effect.

We study the transport of self-propelled particles from one free chamber to another across two stripe-like areas of dense porous medium. The medium is mimicked by arrays of obstacles. We find that active motion could greatly speed up the transport of particles.

Quantitative decision making for a groundwater monitoring and subsurface contamination early warning network.

With the increased development of oil and gas activities in northern Colorado, public concerns over the environmental impacts associated with well drilling and hydraulic fracturing have continued to rise. Issues such as leakages of "toxic" products from oil and gas operations to the subsurface environment (such as groundwater contamination) have led to community action and state regulations related to the establishment of groundwater quality monitoring sites in oil and gas activity areas, particularly those adjacent to urban development. Colorado Water Watch was a groundwater quality monitoring network comprised of seven monitoring wells in northern Colorado to monitor groundwater quality near oil and gas wells and give early warnings of contamination.

Microrotor of a chain-grafted colloidal disk immersed in the active bath: The impact of particle concentration, grafting density, and chain rigidity.

In an earlier work, we discussed the possibility to realize a microrotor by immersing a chain-grafted colloidal disk in a thin film of active-particle suspension. Under certain conditions, the colloidal disk rotates unidirectionally driven by the bath active particles. Here we systematically study the role of active-particle concentration, grafting density, and chain rigidity in the phenomenon of the spontaneous symmetry breaking of the chain configurations and the unidirectional rotation of the disk.

Spontaneous symmetry breaking induced unidirectional rotation of a chain-grafted colloidal particle in the active bath.

Exploiting the energy of randomly moving active agents such as bacteria is a fascinating way to power a microdevice. Here we show, by simulations, that a chain-grafted disk-like colloidal particle can rotate unidirectionally and hence output work when immersed in a thin film of active particle suspension. The collective spontaneous symmetry breaking of chain configurations is the origin of the unidirectional rotation.

The unique role of bond length in the glassy dynamics of colloidal polymers.

Bond length is generally not considered as a controllable variable for molecular polymers. Hence, no experimental, simulation or theoretical research, to our knowledge, has examined the influence of bond length on the glassy dynamics of polymers. Recently, a new class of assembling materials called "colloidal polymers" has been synthesized.

Glassy dynamics of model colloidal polymers: The effect of "monomer" size.

In recent years, attempts have been made to assemble colloidal particles into chains, which are termed "colloidal polymers." An apparent difference between molecular and colloidal polymers is the "monomer" size. Here, we propose a model to represent the variation from molecular polymer to colloidal polymer and study the quantitative differences in their glassy dynamics.

A New Self-Consistent Field Model of Polymer/Nanoparticle Mixture.

Field-theoretical method is efficient in predicting assembling structures of polymeric systems. However, it's challenging to generalize this method to study the polymer/nanoparticle mixture due to its multi-scale nature. Here, we develop a new field-based model which unifies the nanoparticle description with the polymer field within the self-consistent field theory.

Brush in the bath of active particles: Anomalous stretching of chains and distribution of particles.

The interaction between polymer brush and colloidal particles has been intensively studied in the last two decades. Here, we consider a flat chain-grafted substrate immersed in a bath of active particles. Simulations show that an increase in the self-propelling force causes an increase in the number of particles that penetrate into the brush.

Concurrence of aqueous and gas phase contamination of groundwater in the Wattenberg oil and gas field of northern Colorado.

The potential impact of rapid development of unconventional oil and natural gas resources using hydraulic fracturing and horizontal drilling on regional groundwater quality has received significant attention. Major concerns are methane or oil/gas related hydrocarbon (such as TPHs, BTEX including benzene, toluene, ethybenzene and xylene) leaks into the aquifer due to the failure of casing and/or stray gas migration. Previously, we investigated the relationship between oil and gas activity and dissolved methane concentration in a drinking water aquifer with the major finding being the presence of thermogenic methane contamination, but did not find detectable concentrations of TPHs or BTEX.

Theory of activated dynamics and glass transition of hard colloids in two dimensions.

The microscopic nonlinear Langevin equation theory is applied to study the localization and activated hopping of two-dimensional hard disks in the deeply supercooled and glass states. Quantitative comparisons of dynamic characteristic length scales, barrier, and their dependence on the reduced packing fraction are presented between hard-disk and hard-sphere suspensions. The dynamic barrier of hard disks emerges at higher absolute and reduced packing fractions and correspondingly, the crossover size of the dynamic cage which correlates to the Lindemann length for melting is smaller.

Distribution and origin of groundwater methane in the Wattenberg oil and gas field of northern Colorado.

Public concerns over potential environmental contamination associated with oil and gas well drilling and fracturing in the Wattenberg field in northeast Colorado are increasing. One of the issues of concern is the migration of oil, gas, or produced water to a groundwater aquifer resulting in contamination of drinking water. Since methane is the major component of natural gas and it can be dissolved and transported with groundwater, stray gas in aquifers has elicited attention.