Lateral memristors consisting of planar Ag electrodes (with sub-micrometer separation) supported on thin films of amorphous zinc-tin-oxide have been characterized. After an initial filament-forming process, each device exhibited volatile, resistive switching. In the low resistance state, the transport mechanism and conductance depended on prior activity and on the imposed current limit, mimicking biologic synaptic plasticity. Microscopic observations performed on each device revealed nanoscale filaments between the electrodes. These filaments were subject to Rayleigh instability and exhibited relaxation times determined by their effective radii. The relaxation times and on:off resistance ratios suggest suitability for threshold switching selector devices.

We introduce the asprilo1 framework to facilitate experimental studies of approaches addressing complex dynamic applications. For this purpose, we have chosen the domain of robotic intra-logistics. This domain is not only highly relevant in the context of today's fourth industrial revolution but it moreover combines a multitude of challenging issues within a single uniform framework. This includes multi-agent planning, reasoning about action, change, resources, strategies, etc. In return, asprilo allows users to study alternative solutions as regards effectiveness and scalability. Although asprilo relies on Answer Set Programming and Python, it is readily usable by any system complying with its fact-oriented interface format. This makes it attractive for benchmarking and teaching well beyond logic programming. More precisely, asprilo consists of a versatile benchmark generator, solution checker and visualizer as well as a bunch of reference encodings featuring various ASP techniques. Importantly, the visualizer's animation capabilities are indispensable for complex scenarios like intra-logistics in order to inspect valid as well as invalid solution candidates. Also, it allows for graphically editing benchmark layouts that can be used as a basis for generating benchmark suites.

OBJECTIVES/SPECIFIC AIMS: Low cancer clinical trial (CCTs) enrollment may contribute to the poor survival improvement for adolescents and young adults (AYAs, aged 15–39 years) with cancer. Treatment site is thought to exacerbate this problem. This study evaluated whether differences in CCT availability explain lower CCT enrollment depending on treatment site for AYAs. METHODS/STUDY POPULATION: This prospective, observational cohort study was conducted at an academic children’s hospital and an adult cancer hospital, 2 affiliated sites within a NCI-designated Comprehensive Cancer Center over 13 months. In consecutive AYA patients newly diagnosed with cancer at both site, it was determined whether an appropriate CCT existed nationally, was available locally, and if enrollment occurred. The proportions of AYAs in these categories were compared by site using the χ2 test. RESULTS/ANTICIPATED RESULTS: Among 152 consecutive AYA patients, 68 and 84 were treated at the children’s hospital and adult cancer hospital, respectively. AYAs treated at the children’s hospital had similar CCT existence nationally compared with AYAs treated at the adult hospital [36/68 (52.9%) vs. 45/84 (53.6%), p=0.938]. However, a significantly higher percentage of children’s hospital treated AYAs than adult hospital treated AYAs had an available CCT [30/68 (44.1%) vs. 14/84 (16.7%), p<0.001]. Enrollment percentages were similarly low in both groups [8/68 (11.8%) vs. 6/84 (7.1%), p=0.327]. DISCUSSION/SIGNIFICANCE OF IMPACT: Significantly fewer AYAs treated at the adult hospital had a CCT available, but national existence was similar at both sites. This suggests that institutional barriers to opening CCT have more importance at adult centers.

In complex reasoning tasks, as expressible by Answer Set Programming (ASP), problems often permit for multiple solutions. In dynamic environments, where knowledge is continuously changing, the question arises how a given model can be incrementally adjusted relative to new and outdated information. This paper introduces Ticker, a prototypical engine for well-defined logical reasoning over streaming data. Ticker builds on a practical fragment of the recent rule-based language LARS, which extends ASP for streams by providing flexible expiration control and temporal modalities. We discuss Ticker's reasoning strategies: first, the repeated one-shot solving mode calls Clingo on an ASP encoding. We show how this translation can be incrementally updated when new data is streaming in or time passes by. Based on this, we build on Doyle's classic justification-based truth-maintenance system to update models of non-stratified programs. Finally, we empirically compare the obtained evaluation mechanisms.

This article describes a formal proof of the Kepler conjecture on dense sphere packings in a combination of the HOL Light and Isabelle proof assistants. This paper constitutes the official published account of the now completed Flyspeck project.

Phosphorus is incorporated into single crystal diamond during epitaxial growth at higher concentrations on the (111) crystallographic surface than on the (001) crystallographic surface. To form n+-type regions in diamond for semiconductor devices it is beneficial to deposit on the (111) surface. However, diamond deposition is faster and of higher quality on the (001) surface. A preferential etch method is described that forms inverted pyramids on the (001) surface of a substrate diamond crystal, which opens (111) faces for improved phosphorus incorporation. The preferential etching occurs on the surface in regions where a nickel film is deposited. The etching is performed in a microwave generated hydrogen plasma operating at 160 Torr with the substrate temperature in the range of 800-950 °C. The epitaxial growth of diamond with high phosphorus concentrations exceeding 1020 cm-3 is performed using a microwave plasma-assisted chemical vapor deposition process. Successful growth conditions were achieved with a feedgas mixture of 0.25% methane, 500 ppm phosphine and hydrogen at a pressure of 160 Torr and a substrate temperature of 950-1000°C. The room temperature resistivity of the phosphorus-doped diamond is 120-150 Ω-cm and the activation energy is 0.027 eV.

Triticale possesses favourable agronomic attributes originating from both its wheat and rye progenitors, including high grain and biomass yields. Triticale, primarily used as animal feed in North America, is an excellent candidate for production of industrial bio-products. Little is known about the coordination of gene expression of rye and wheat genomes in this intergeneric hybrid, but significant DNA losses from the parental genomes have been reported. To clarify the regulation of gene expression in triticale, we carried out 454 sequencing of cDNAs obtained from root, leaf, stem and floral tissues in different lines of triticale and rye exhibiting different phenotypes and assembled reads into contigs. Related to the data assembly were the absence of reference genomes and the paucity of rye sequences in GenBank or other public databases. Consequently, we have sequenced cDNA libraries from roots, seedlings, leaves, floral tissues and immature seeds to facilitate the identification of triticale sequences originating from rye. To further characterize the wheat-derived cDNAs, we also developed a database close to 25,000 non-redundant full-length wheat coding sequence genes, based on existing databases and contigs that were verified against protein sequences from the grass genomes of Brachypodium distachyon, rice, sorghum and maize.

Extended abstract of a paper presented at Microscopy and Microanalysis 2010 in Portland, Oregon, USA, August 1 – August 5, 2010.

Two common problems with implantation after cancerous tumor resection are cancer recurrence and bacteria infection at the implant site. Tumor resection surgery sometimes can not remove all the cancerous cells, thus, cancer can return after implantation. In addition, bacteria infection is one of the leading causes of implant failure. Therefore, it is desirable to have anti-cancer and anti-bacterial molecules which both rapidly (for anti-infection purposes) and continuously (for anti-cancer purposes) are available at the implant site following implantation. Therefore, the objective of the present in vitro study was to create a multi-functional coating for anti-cancer and anti-bacterial orthopedic implant applications. Elemental selenium was chosen as the biologically active agent in this effort because of its known chemopreventive and anti-bacterial properties. To achieve that objective, titanium (Ti), a conventional orthopedic implant material was coated with selenium (Se) nanoclusters. Different coating densities were achieved by varying Se concentration in the reaction mixture. Titanium substrates coated with Se nanoclusters were shown to enhance healthy osteoblast (bone-forming cell) and inhibit cancerous osteoblast proliferation in co-culture experiments. Functions of S. epidermidis (one of the leading bacteria that infect implants) were inhibited on Ti coated with Se-nanoclusters compared to uncoated materials. Thus, this study provided for the first time a coating material (selenium nanoclusters) to the biomaterials’ community to promote healthy bone cells’ functions, inhibit cancer growth and prevent bacteria infection.

Current orthopedic implants have numerous problems that include poor osseointegration, stress shielding and wear debris-associated bone cell death. In addition, numerous patients receive orthopedic implants as a result of bone cancer resection, yet none of the current orthopedic materials are designed to prevent either the occurrence or reoccurrence of cancer. The objective of this study was to transform a traditional orthopedic material into an implant that can both restore bone and prevent bone cancer growth at the implant-tissue interface. Elemental selenium was chosen as the biologically active agent in this material because of its known chemopreventive and chemotherapeutic properties. It was found that when selenite salts were reduced by glutathione in the presence of an immersed substrate (titanium (Ti), stainless steel (SS) or ultra high molecular weigh polyethylene (UHMWPE)), elemental selenium nucleated and grew into adherent, hemispherical nanoclusters. For each type of substrate (Ti, SS and UHMWPE), three types of surfaces with different selenium surface densities were fabricated. The zero oxidation state of selenium was confirmed on Ti substrates by XPS profiles. Compared to uncoated Ti and SS substrates, the high-density selenium-coated surfaces inhibited cancerous bone cell functions while promoting healthy bone cell functions. Very little selenium was also found to release (about 250ppb) into the cell culture media after 3 days of immersion. These findings showed for the first time the potential of using selenium nanoclusters as a coating to transform a traditional orthopedic material into a bone cancer inhibiting implant.