Quantum mechanical oscillations of a many-body system about a local potential minimum can in a first approximation be modeled by a set of harmonic oscillators about a local potential minimum. In more sophisticated models one also has to consider anharmonic effects.
Here we present the first steps towards a systematic solution of ground and excited state energies for a set of coupled quartic oscillators using coupled cluster techniques. We present the general approach of the equation of motion coupled cluster (EOM-CC) method. We give illustrative details of the diagrammatic approach to obtaining our operating equations as well as the resulting EOM-CC equations for a simple system of coupled harmonic oscillators perturbed by a quadratic perturbation. We point to the connection with Bogoliubov transformations and finally we illustrate the numerical behavior of the EOM-CC non-linear iterations and matrix diagonalization of our effective Hamiltonian obtained with our Python code.

With the advent of graphene, there has been an interest in utilizing this material and its derivative, graphene oxide (GO) for novel applications in nanodevices such as bio and gas sensors, solid state supercapacitors and solar cells. Although GO exhibits lower conductivity and structural stability, it possesses an energy band gap that enables fluorescence emission in the visible/near infrared leading to a plethora of optoelectronic applications. In order to allow fine-tuning of its optical properties in the device geometry, new physical techniques are required that unlike existing chemical approaches yield substantial alteration of GO structure. Such desired new technique is one that is electronically-controlled and lead to reversible changes in GO optoelectronic properties. In this work, we for the first time investigate the methods to controllably alter the optical response of GO with the electric field and provide theoretical modelling of the electric field-induced changes. Field-dependent GO emission is studied in bulk GO/PVP films with up to 6% reversible decrease under 1.6 V/µm electric fields. On an individual flake level, a more substantial over 50% quenching is achieved for select GO flakes in polymeric matrix between interdigitated microelectrodes subject to two orders of magnitude higher fields. This effect is modelled on a single exciton level by utilizing WKB approximation for electron escape form the exciton potential well. In an aqueous suspension at low fields GO flakes exhibit electrophoretic migration indicating a degree of charge separation and a possibility of manipulating GO materials on a single-flake level to assemble electric field-controlled microelectronics. As a result of this work, we suggest the potential of varying the optical and electronic properties of GO via the electric field for the advancement and control over its optoelectronic device applications.

In order to determine correct dosage of chemotherapy drugs, the effect of the drug must be properly quantified. There are two important values that characterize the effect of the drug: ε_max is the maximum possible effect from a drug, and IC_50 is the drug concentration where the effect diminishes by half. We use mathematical models to estimate how the values depend on measurement time and model choice. Improper choice of growth model is problematic and can lead to differences in predictions of treatment outcomes for patients. This work intends to understand how choice of model and measurement time affects the relative drug effect and causes the differences in predictions for the most effective dose of anticancer drug for a patient. This work determines the correct doses before trying those in patients to get the most effective therapeutic treatment.

Star clusters are key chemical and age tracers of Milky Way evolution. The use of star clusters to provide significant constraints on galaxy evolution, however, has been limited due to discrepancies between different studies. This work seeks to add additional open clusters into an existing large, uniform chemical abundance system. We analyze spectra of giant stars in 31 open clusters and, using a machine learning method called The Cannon, determine iron abundances. This uniform analysis is compared with previous results, and we present new chemical abundances of 12 star clusters.

Antimicrobial action of micro- and nanoscale ZnO particles has been documented, but the fundamental physical mechanisms driving this action are still not identified . We hypothesize that one of the key mechanisms behind the antibacterial action of ZnO is rooted in interactions between ZnO surfaces and extracellular material. Crystalline structure of ZnO results in two distinct types of crystallographic surfaces: polar (charged) and non-polar (neutral). The excess charge and electronic states at the polar surfaces of micro- and nano-scale ZnO particles may affect interfacial phenomena with surrounding media. Therefore, it is feasible that the relative abundance of such polar surfaces could significantly influence their antibacterial action. In this study we use a hydrothermal growth method established in our lab to synthesize ZnO crystals with different controllable surface morphologies. We study the effects of relative abundance of polar surfaces on antibacterial action. These experiments performed in conjunction with optoelectronic studies of ZnO crystals yield information regarding the fundamental nature of their antibacterial action.

Polysulfone is a stable and strong semitransparent thermoplastic material that is applicable in many industries due to its resistance to low and high temperatures, as well as unique hydrophobic properties. Hydrophobic films are frequently used in waterproofing devices and to improve the efficiency of water vessels. It was recently discovered that polysulfone has a unique behavior as it changes from being hydrophobic to hydrophilic after exposure to a UV radiation. In order to elucidate the mechanisms behind this phenomenon we are performing surface photovoltage (SPV) studies on polysulfone thin films, which is done for the first time, to the best of our knowledge. Whereas SPV is sensitive to buried interfaces, SPV spectral features contain contributions not only from the polysulfone films, but from the silicon wafer and the silicon oxide layer beneath the polymer films. Thereby, to identify the signal germane to the polysulfone properly, we employ in our studies polysulfone films of varying and controllable thicknesses. To establish controllable methods for producing such films by spin coating, we use different concentrations of polysulfone in solutions with different spin rates. Film thickness is determined employing a thin film analyzer. From these thicknesses, trends are established relating film thickness to solution concentration and spin rate. SPV studies provide initial investigations into surface electronic transitions and mechanisms behind the hydrophobic ‘flipping’ of polysulfone.

The interaction between low-mass galaxies are of critical importance for the growth and evolution of galaxies. The star formation can be enhanced during interactions between massive galaxies, but very few studies focus on the interaction between low-mass galaxies. In this work, we explored the current star-formation surface density in both isolated and interacting galaxies and look for enhanced star formation during the interactions. A galaxy will be considered as a galaxy pair candidate if the physical separation between it and its closest low-mass galaxies is smaller than 5000 light years, otherwise it will be put into the isolate galaxy sample. This sample intentionally excludes galaxies with a massive galaxy neighbor nearby as massive neighbors can harass low-mass companion galaxies and can cause them to become quenched. This project is the first attempt to systematically study how the internal star-formation activities of low-mass galaxies are influenced by outer environment.

Large galaxies are made up of smaller satellite galaxies. This makes these satellite galaxies crucial to understanding how stars form. Shallow gravity wells make them extremely sensitive to internal and external disturbances. Therefore, they are excellent laboratories to explore stellar physics. We use multi-body simulations of a Milky Way-like galaxy to explore the stellar properties of satellite galaxies surrounding a possible Large Magellanic Cloud (LMC). LMC is the largest satellite galaxy of the Milky Way. We compare the resulting properties such as chemical composition, light, radial distribution to observations from McConnachie et al. 2012.

The present experiment was designed to explore the role of the central amygdala (CeA) in the hypothesized neural circuit underlying reward loss, and its relationship with the emotional self-medication (ESM) hypothesis utilizing the DREADD technique to remotely control neural activity. Rats received intracranial infusion of inhibitory DREADDs to allow for transient inactivation of the CeA, obtained via systemic injection of clozapine N-oxide (CNO), the activator drug for DREADDs. Animals were exposed to a 32-to-2% sucrose downshift in the consummatory successive negative contrast (cSNC) situation. After each cSNC session, animals were given simultaneous access to ethanol and water in a 1-h, two-bottle preference test. During the preshift phase (sessions 1-10), animals had access to either 32% (32/CNO and 32/VEH) or 2% (2/CNO and 2/VEH) sucrose. During the postshift phase (sessions 1-15), 32% groups were downshifted to 2% sucrose, whereas 2% groups were unshifted. Prior to downshifted sessions 11-13, animals received an i.p. injection of either CNO or vehicle. At the end of the 15-day two-task behavioral paradigm, animals were tested on the open-field task for two consecutive days in alternate dark and light conditions. The results indicated that CeA inactivation prior to reward devaluation session eliminated the cSNC effect (32/CNO), a hint of ESM effect was present in animals that experienced the reward devaluation under normal CeA activity (32/VEH), but not in animals for which the CeA was inhibited (32/VEH), and open-field activity showed a trend, albeit nonsignificant, toward increased activity in animals with inhibited CeA activity (32/CNO). One important contribution of this experiment involves the use of the DREADD technique to achieve transient inactivation of brain regions. This approach produced behavioral consequences in the cSNC task similar to those obtained in previous research using lidocaine microinfusions. The results of this study suggest that the DREADD approach is a valuable method to manipulate neural activity to further explore the role of these brain regions in our hypothesized reward loss circuitry.

Research has explored the effects of adoption on the adopted child as well as the parent-child relationship in an adoptive family. However, little is known about the effects of adoption on the remaining members of an adoptive family—the adoptive siblings, defined as the biological children in families who adopted one or more children. The current study aims to examine the adoptive sibling experience in effort to understand a) the effects of adoption on this population and b) which, if any, precluding factors are related to these effects. Participants included adult siblings to at least one adoptee who completed an online survey about their family and experiences. The survey included items about family demographics, free-response items about specific adoption experiences, a measure of potential risk and protective factors created for this study, and assessments about sibling relationship quality and overall family functioning. Results revealed five emerging themes in the adoptive sibling experience: 1) “my adoptive sibling was the best thing to happen to our family,” 2) “it was a hard experience but has shaped me to be who I am today,” 3) “my adoptive sibling required all my parents’ attention and I was pushed aside,” 4) “I am like a second parent to my adoptive sibling,” and 5) “it was the worst thing to ever happen to our family.” Results also revealed that better family communication and greater siblings’ involvement in the adoption process are related to a more positive response to adoption, a closer relationship with the adopted sibling, and more positive views of the family system. Findings improve our preliminary understanding of how adoption affects adoptive siblings and imply that targeted interventions for adoptive siblings may be needed; however, more research is needed to better understand the factors involved.

Will work for alcohol! Reward value of alcohol in rats.
Joanna B. Thompson and Mauricio R. Papini

Abstract

The misuse of alcohol is a prevalent problem in the United States, contributing to an array of public health, social, and economic issues. It is estimated that over 16 million Americans each year receive a diagnosis of an alcohol use disorder (AUD) which contributes to an economic burden upwards of $249 billion (NIAAA, 2017). Previous research has shown that alcohol has rewarding properties which motivate organisms to engage in voluntary, oral consumption (Jupp et al., 2011). Although studies have provided evidence for decreased alcohol consumption in rodents, no studies to date have examined high concentration alcohol (upwards of 60%). We used a mixed Pavlovian-instrumental paradigm to train rats to self-administer solutions of 0, 2, 10, and 66% alcohol. Once oral self-administration was established, rats were switched to a progressive-ratio schedule of reinforcement where a greater response effort was required to gain access to each of the alcohol solutions. Solution presentation was switched between rats each day. Higher levels of behavioral responding to an empty sipper to gain access to the alcohol solution was indicative of the reward value of that particular solution. Rats exhibited similar breakpoints for each alcohol solution, though expended less effort for 0% (water). Future directions will involve antagonizing the orexin-1 receptor, which has demonstrated to decrease alcohol consumption (Anderson et al., 2014). A non-peptide selective orexin-1 receptor antagonist, SB-334867, will be administered prior to sessions of progressive-ratio alcohol self-administration to determine the effective dose (0, 1, 5, or 10 mg/kg) at decreasing self-administration of alcohol. These findings are relevant for developing an animal model of alcohol intoxication aimed at a potential clinical drug therapy for alcohol abuse.

Anderson, R., Becker, H., Adams, B., Jesudason, C., & Rrick-Kehn, L. (2014). Orexin-1 and orexin-2 receptor antagonists reduce alcohol self-administration in high-drinking rodent models. Frontiers in Neuroscience, 8, 33.
Jupp, B., Krivdic, B., Krstew, E., & Lawrence, A.J. (2011). The orexin-1 receptor antagonist SB-334867 dissociates the motivational properties of alcohol and sucrose in rats. Brain Research, 1291(1), 54-59.
National Institute on Alcohol Abuse and Alcoholism. (2017). Alcohol use disorder. Retrieved February 2019 from https://www.niaaa.nih.gov/alcohol-health/overview-alcohol-consumption/alcohol-use-disorders

The Texas horned lizard (Phrynosoma cornutum) is considered a threatened species in Texas and Oklahoma, due to substantial range declines over the past several decades. Horned lizards are believed to be highly vulnerable to habitat alterations, due to extreme specialization on ants, particularly harvester ants (Pogonomyrmex spp.). I analyzed diets of Texas horned lizards from two small towns by identifying exoskeletons of prey items found in fecal pellets. I assessed dietary specialization by comparing diet to prey availability, based on pitfall traps and abundance of harvester ant colonies. My results found strong spatio-temporal variation with respect to prey abundance and consumption. Harvester termites (Tenuirostritermes cinereus) and big-headed ants (Pheidole spp.) accounted for over 70% of all prey consumed. Average consumption of big-headed ants was comparable to their abundance in pitfall traps, but consumption of harvester termites was much higher than their pitfall trap abundance. Consumption of harvester ants is strongly correlated with the number of harvester ant colonies within study sites and horned lizard home ranges. Dietary diversity and richness were positively related to the area of dense vegetation in sites and lizard home ranges. These results suggest horned lizards in these towns adjust diet in relation to prey availability, which is considered a characteristic of generalist predators. The superior nutritional value of harvester termites relative to similarly sized ants could explain the apparent lack of size-based prey preference in these horned lizard populations.

Exposure to contaminants during development has the potential to cause adverse biological alterations that can persist through depuration periods and into adulthood. This study examined the effects of chemically induced, early-life-stage thyroid disruption on endpoints associated with thyroidal and reproductive function in the fathead minnow (Pimephales promelas). Fish were exposed to propylthiouracil (PTU) from 1 to 43 days post hatch (dph) to induce hypothyroidism. At the end of exposure, length and weight were measured and samples were taken for gene expression analysis. The remaining fish were transferred to un-dosed water and raised to maturity and, at 164 dph, a 21-day breeding assay was performed. At the end of exposure, fish exposed to PTU had significantly reduced length and weight indicating successful thyroid disruption. There were also significant differences in expression of several genes involved in the thyroidal and reproductive signaling systems. After maturation, there were no significant differences in any morphological variables. During the 21-day breeding assay, fish from the PTU exposure group had significantly reduced overall fecundity relative to controls. Based on data collected so far, it appears that this reduction in fecundity is due to either ovarian dysfunction or alterations in reproductive behavior. The results show that early-life-stage hypothyroidism can affect reproductive function later in life even after thyroid related endpoints have returned to control levels.

Mercury (Hg) is a toxic heavy metal that has contaminated all aquatic food webs and can pose a health risk to aquatic predators. Piscivorous birds are apex predators in aquatic systems that are exposed to mercury through the consumption of Hg-contaminated fish. Although there is extensive data on Hg concentrations in fish, the data on Hg concentrations in birds is relatively limited. I used a previously published relationship between Hg concentrations in piscivorous bird blood and Hg concentrations in prey fish to estimated Mg concentrations in the blood of four species of piscivorous wading birds in the south central U.S. [Little Blue Herons (Egretta caerulea), Green Herons (Butorides verescens), Great Egrets (Ardea albus) and Great Blue Herons (Ardea herodias)] from the concentration of Hg found in bluegill (Lepomis macrochirus). Estimated Hg concentrations in bird blood increased with the size of prey fish consumed and was lowest for Little Blue Herons and Green Herons, intermediate for Great Egrets and highest for Great Blue Herons. Estimated Hg concentrations in bird blood was greatest in ecoregions where conifer-adjusted mercury deposition was highest. Mercury risk to bird health varied with bird species and increased with Hg deposition. Little Blue Herons, Green Herons, Great Egrets and Great Blue Herons were at some level of risk in 14, 36, 86 and 100% of ecoregions, respectively. The threat of Hg to the health of piscivorous wading birds may not be unique to south central U.S. and may extend throughout the southeastern United States due to high Hg deposition and extensive forest coverage.

Understanding bacterial virulence is important because it provides insight into the molecular basis behind bacterial infections. With the decreased efficacy of antibiotics due to the development of drug resistance, this knowledge could be used to identify specific targets for new pharmacological targets thereby strengthening our arsenal against these pathogens. Currently, our main mechanism by which to evaluate in vivo virulence is the mouse model (Mus musculus). While this model is effective, there are substantial ethical and resource constraints associated with vertebrate use. In order to provide alternative in vivo testing models, this study investigated the invertebrate wax worm larvae, G. mellonella, as an in vivo infection model for B. anthracis. To validate the ability of G. mellonella to discern attenuated bacterial strains, previously identified virulence mutants were constructed and assessed. This model proved capable of distinguishing between virulent and avirulent strains. Next, we tested whether G. mellonella could identify novel virulence mutants. A small collection of transposon mutants was screened for deficits in reactive oxygen species (ROS) survival and iron acquisition using in vitro screens. This yielded 10 attenuated mutants. These mutants were then assessed in G. mellonella and 2 were found to have an in vivo phenotype. These results demonstrate the potential effectiveness of G. mellonella as a future infection model and could increase the efficiency in the identification of novel bacterial virulence mutants.

Dreissena polymorpha, zebra mussels, are an invasive species of freshwater bivalves that have recently spread into bodies of water across North America via the Great Lakes. Zebra mussels are mainly spread throughout the United States by their free-swimming larvae called veligers that are moved from waterbody to waterbody by human boat traffic, attributing to the success of their invasive spread. Once an adult zebra mussel population is established, they proliferate quickly and cause many problems to the ecosystem by their efficient filter feeding abilities. They also cause damage to boating and water treatment equipment by tightly attaching to many hard surfaces. Zebra mussels have recently entered many Texas waterways, indicating that they have possibly adapted to conditions outside of originally expected for a cold water species that are not representative of the Great Lakes region. The focus of this study was to look at various environmental factors which may affect zebra mussel survival and reproduction including temperature and the effects of a copper-based molluscicide, EarthTec QZ, as a potential mechanism of control. Zebra mussel survival and reproductive success were examined in various experiments to gain an overall understanding of the effects at all zebra mussel life stages.

Habitat maps derived from remotely sensed data are strong predictors of wildlife distributions, outperforming traditional on the ground vegetation structure surveys. Texas Parks and Wildlife created a statewide habitat map in 2014 featuring 398 vegetation classes to 10-meter resolution. The Great Trinity Forest is the largest urban forest in the United States, with 3,000 continuous hectares within the city of Dallas. As part of our wider study of the forest’s wildlife, we edited Texas Parks and Wildlife’s habitat to more accurately and meaningfully reflect habitat distinctions in the Great Trinity Forest. First we adjusted the locations and boundaries of waterways to reflect changes in their location over the past four years. Then we reclassified the bottomland hardwood forest habitat type (BHF) to reflect different succession stages of forest growth. Using LIDAR and aerial images we calculated canopy heights and reclassified BHF using those heights as primary BHF, secondary BHF, or early successional bottomlands.

Methylmercury (MeHg) is an environmental contaminant that can have adverse effects on wildlife. Because inorganic Hg is converted to MeHg primarily in aquatic ecosystems, studies of MeHg contamination of food webs have historically focused on aquatic organisms. However, recent studies have found that emergent aquatic insects (e.g. mayflies and dragonflies) can transport MeHg to terrestrial predators like songbirds, and this could have implications for species in decline such as Red-winged blackbirds (Agelaius phoeniceus). Red-winged blackbirds are odonate (dragonflies and damselflies) predators, and odonates can make up 50 – 90% of a Red-winged blackbird’s diet during the breeding season. Red-winged blackbirds have declined throughout their range by 30% over the last 50 years. Their decline is due in part to loss of wetland habitat, but the consumption of MeHg contaminated prey items could also be having an effect. Several studies have reported MeHg contamination of Red-winged blackbirds, and yet, the potential effect of diet on MeHg contamination in Red-winged blackbirds has not been studied. I collected data on blood MeHg level of Red-winged blackbird nestlings and the emergence rate of odonates during the summer of 2017 at the Eagle Mountain Hatchery Experimental Pond Facility in Tarrant County, Texas. I used the ArcGIS Space Time Cube to identify spatiotemporal hot spots of nestling MeHg level and odonate emergence, and I used linear regression models to see how well proximity to odonate emergence hotspots predicted nestling MeHg hotspots.

Many rainbow trout (Oncorhynchus mykiss) populations exhibit partial migration, where resident and migrant individuals coexist in a single population. Due to anthropogenic, environmental, and population-specific factors, migratory individuals have been decreasing in frequency across the continental United States. Biologically, whether an individual will migrate is determined by both genetic and environmental factors. Although migration in many salmonids is known to be highly heritable, the environment plays an overriding role. Previous studies investigating the genetic basis of migration have failed to control for environmental variance and, consequently, the genes and regions of the genome underlying the development of the migratory phenotype remain unknown. We used data from a common garden experiment to identify single nucleotide polymorphisms (SNPs) significantly associated with migration in the F1 generation of a resident-by-resident and a migrant-by-migrant cross. We genotyped 192 F1 individuals on an Affymetrix SNP chip at 57,501 known polymorphic locations throughout the genome. We identified 5002 significant SNPs in the migrant-by-migrant family and 429 significant SNPs in the resident-by-resident family, using an FDR-corrected p-value of 0.01. For the migrant cross, we located significant markers associated with 28 genes whose functions are connected to pathways previously hypothesized to be important in migration. Five genes on three chromosomes were associated with migration in both familial crosses, suggesting that these regions are important in determining life history regardless of familial origin in this population. These data will be further used to develop a model to predict life history in individuals that are yet to make that determination. Understanding the genetic factors involved in the decision to migrate, through the identification of polymorphisms associated with migration, will assist fisheries managers in restoring and maintaining migratory rainbow trout populations.

The combination of inorganic porous silicon (pSi) and flexible biocompatible polymers has been shown to yield more beneficial hybrid scaffolds for tissue engineering (i.e. use of synthetic materials to facilitate healing). PSi has a variety of tunable properties, including pore size, pore volume and non-toxic degradation. The addition of a biocompatible polymer such as polycaprolactone (PCL) can provide control over shape and serve as an additional drug delivery component.
In this work, composite materials consisting of oxidized porous silicon (ox-pSi) with a particle size of ~ 30 μm and pore size of 40-100 nm and PCL porous fibers. Porous fibers were fabricated using an electrospinning method into sheets of desired thickness (0.1-0.4 mm), fiber diameter 3-4 μm, and fiber pore size 300-500 nm. Ox-pSi particles previously loaded with the anticancer drug-camptothecin (CPT) were placed between two sheets (6 mm in diameter each) and sealed at the edges, resulting in ~65% loading of ox-pSi. Drug release from the ox-pSi particles alone and ox-pSi/porous PCL fiber composites was monitored fluorometrically in phosphate buffered saline (PBS), showing a distinct release profile for each material.
Ox-pSi/p-PCL fiber composites release a CPT payload in accordance with the Higuchi release model and showed a significant decrease in burst effect compared to ox-pSi particles only. In addition, composite evolution after 5 weeks in PBS at 37 oC was examined using gravimetry, differential scanning calorimetry (DSC), and field emission scanning electron microscopy (FESEM). Overall weight loss of the composites was about 50%, mainly attributed to pSi particles dissolution and some polymer hydrolysis. Preliminary DSC results show that high surface area porous PCL fibers are less crystalline compared to solid PCL fibers, suggesting a faster hydrolysis route.

Europium contrast agents have been extensively investigated as an alternative to typical Gd3+ species for imaging. This is due to the dual imaging modalities which can accessed dependent on the oxidation state of the europium metal center (T1 or PARACEST). To achieve these functionalities, the europium containing complex must be stable enough to support both oxidation states (+3 and +2). In collaboration with UTSW, an electrochemical investigation was completed to understand the effects of the ligand environment on the metal center as a direct result of glycine modification to the ligand scaffold, DOTA. Increasing amide functionalities in close proximity to the europium core result in a positive shift in the potential in comparison to the acetate arms associated with DOTA. Furthermore, the addition of the glycine moiety to the pendant arms results in redox activity of the ligand itself, making the ligand non-innocent in nature. Additionally, a crystal structure of Eu4 (the tetraglycinate DOTA derivative) was obtained and compared to known lanthanide complexes.

Cerium (IV) oxide, or CeO2, nanomaterials have displayed antioxidant and enzyme mimetic activities due to a Ce3+/Ce4+ redox capability enhanced through oxygen vacancies and mobility. Tri-valent, fluorescent ions such as Eu3+ increase the Ce3+/Ce4+ ratio and oxygen vacancy concentration, while contributing fluorescent properties to the nanomaterial. The combination of these attributes make europium doped cerium oxide (EuCeO¬2) nanomaterials appealing candidates for various biological applications.
To complement our earlier efforts on the synthesis and properties of EuCeO2 nanowires, nanorods, and nanocubes, this presentation addresses a new, complementary structure, EuCeO2 nanotubes. The nanotubes are prepared via deposition and subsequent oxidation of Eu-doped Ce(OH)3 to form a EuCeO2 shell on sacrificial ZnO nanowires.
Previous synthetic routes to CeO2 nanotubes have been reported featuring carbon nanotubes as sacrificial templates, the etching of cerium-based nanorods, and other less-common methods . These routes have struggled with clear evidence for distinct nanotube formation, as well as control over nanotube dimensions. Our use of a ZnO core allows for facile manipulation of inner diameter and length of the nanotube following etching of the core.
The synthesized nanotubes were characterized using scanning and transmission microscopy (SEM and TEM) for morphology, energy dispersive x-ray (EDX) for elemental composition, and photoluminescence to track europium fluorescence. Synthesized nanotubes had inner diameters from 40 nm to 200 nm, based on the ZnO core. Following synthesis and characterization, the nanotubes will be tested for use as a drug delivery vector, using ibuprofen as a model.

Diffusiophoresis is the migration of a relatively large particle (e.g., protein, polymer, nanoparticle) induced by a gradient of salt concentration. The salt-induced diffusiophoresis of lysozyme, a model protein, at pH 4.5 and 25 °C was examined as a function of salt concentration for three chloride salts: NaCl, KCl and MgCl2. Diffusiophoresis coefficients were theoretically extracted from experimental multicomponent diffusion data by applying irreversible thermodynamics. A selected mass-transfer process was theoretically examined to show that concentration gradients of MgCl2 produce significant lysozyme diffusiophoresis. The dependence of lysozyme diffusiophoresis on salt nature was theoretically examined and linked to protein charge. The effect of salt type on hydrogen-ion titration curves was experimentally characterized to understand the role of salt nature on protein charge. Our findings indicate that diffusiophoresis may be exploited for diffusion-based separation of proteins in the presence of salt concentration gradients and for the enhancement of protein adsorption onto solid surfaces relevant to biosensing applications.

The randomization of 11 bases in the theophylline-binding domain generated a library containing millions of different theophylline riboswitch variants. The dual genetic selection of this molecular library successfully led to the identification of a caffeine-specific synthetic riboswitch. When a chloramphenicol-resistance gene was expressed under control of this caffeine riboswitch, E. coli cells showed chloramphenicol resistance only in the presence of caffeine. For a colorimetric or fluorescence assay, the caffeine riboswitch gene was inserted upstream of the B-galactosidase (LacZ) or green fluorescence protein (GFP) gene, respectively. When tested with various concentrations of caffeine, the enzymatic activity of LacZ or the fluorescence intensity of GFP was proportional to the amount of caffeine, clearly indicating the caffeine-dependent gene regulation by the caffeine riboswitch. The caffeine synthetic riboswitch can be further developed as a biosensor to detect caffeine in complex biological samples such as urine and blood.

Porous silicon (pSi) is a unique nanostructured form of the elemental semiconductor Si. Due to its useful properties governed by its surface chemistry and porous morphology, pSi has been studied in the last few decades in diverse fields extending from electronic device technology to bio-relevant applications.1 Recently, one-dimensional porous nanotubes based on elemental Si (pSiNTs) with a tunable structure (sidewalls, inner void space and lengths) have been successfully synthesized.2 The well-defined structure of pSiNTs offers ample opportunities to study newly emerging properties of this material and innovative applications in multiple areas. For example, recent reports have revealed the use of SiNTs as an efficient template for loading superparamagnetic nanoparticles (Fe3O4), lithium storage and cycling, as well as acting as a template for formation of organometal perovskite nanostructures.3-5
Platinum (Pt) nanoparticles, both free-standing as well as anchored on various surfaces, have attracted widespread attention in nanocatalysis, electronics, and chemotherapeutics.6 In this work, it is suggested that pSiNTs after being functionalized with 3-(aminopropyl)triethoxysilane (APTES) can serve as a platform for Pt nanocrystal (Pt NC) formation. Particularly, incubation of APTES-functionalized SiNTs in potassium tetrachloroplatinate (II) (K2PtCl4) solution under ambient conditions subsequently yields Pt nanoclusters with sizes ranging from 1-3 nm on SiNTs. From high-resolution transmission electron microscopy (HRTEM), nanocrystals with characteristic lattice spacings associated with Pt (d = 0.21 nm) are observed on the nanotubes. The amount of Pt deposited on SiNTs can be sensitively tuned from 20-60 wt% (characterized by TEM Energy Dispersive X-ray Analysis, EDX) by varying concentration of K2PtCl4 and immersion time in this Pt salt precursor.
These findings suggest a new approach to prepare Pt NCs that are of potential benefit to a broad number of applications by using pSiNTs as a template. Further investigations into the properties of the newly discovered Pt NCs-SiNT composites are imperative to evaluate useful applications of this material.
REFERENCES
[1] Porous Silicon for Biomedical Applications, H. Santos, Ed. Cambridge: Woodhead Publishing, 2014.
[2] X. Huang, R. Gonzalez-Rodriguez, R. Rich, Z. Gryczynski, J.L. Coffer, Chem. Commun., 2013, 49, 5760-5762.
[3] P. Granitzer, K. Rumpf, R. Gonzalez, J. Coffer, M. Reissner, Nanoscale Res. Lett. 2014, 9, 413.
[4] R. Gonzalez-Rodriguez, N. Arad-Vosk, N. Rozenfeld, A. Sa'ar, J. L. Coffer, Small, 2016, 12, 4477-4480.
[5] A. T. Tesfaye, R. Gonzalez, J. L. Coffer, T. Djenizian, ACS Appl. Mater. Interfaces, 2015, 7, 20495-20498.
[6] A. Chen, and P. Holt-Hindle, Chem. Rev., 2010, 110, 3767-3804.