Design of novel experimental techniques to investigate the formation of nanoparticle-based tribofilms

Nano-engineered lubricant additives such as organically-active nanoparticles of molybdenum disulphide (Hybrid-milled MoS2) are becoming increasingly popular in the fight against harsh friction and wear that occurs during boundary-layer lubrication. A previous paper (Verma, 2007), has reported improvements in both coefficient of friction and wear scar diameter; however, there exists very little data concerning the methods through which this improvement is achieved. Using techniques such as atomic force microscopy (AFM), nanoindentation, scanning electron microscopy (SEM), focused ion beam (FIB), high resolution transmission electron microscopy (HRTEM) as well as tribometery, the chemical and mechanical characteristics of the nanoparticle based tribofilm are characterized. It was found that after 10 minutes of boundary-layer lubrication, a pad-like film of MoS2 islands approximately 3 microns in diameter are formed on 52100 steel. The thickness of the film was determined to be on the order of 120 nm using FIB as well as nanoindentation

Highly Transparent, Self-cleaning, and Antireflective Nanoparticle Coatings

Current solar panel technologies require a sheet of glass to serve as both mechanical support and to protect the cells from the environment. The reflection from the glass sheet can reflect up to 8% of the incident light, reducing the power output of the panel. Antireflective coatings can be used to allow more light to enter the panel to be converted into usable electricity. However, no solid thin film materials exhibit a low enough index of refraction to serve as antireflective coatings for common solar glass. The main goal of this research was to investigate the self-cleaning, antifogging, and antireflective behavior of low index of refraction silica nanoparticle films, with an ultimate goal to develop a method to deposit these films on glass substrates from aqueous solutions. The optical, wetting, and self-cleaning ability of these films was evaluated at a laboratory scale. It was determined that the film performance could be significantly improved by utilizing a polyvinylpyrrolidone (PVP) adhesion layer during the deposition process. Using this method, the solar weighted transmittance of glass was improved to 97.4%, with peak transmittance of 99.5%, using a double sided coating. The short-circuit current and conversion efficiency of silicon solar cells was improved by a relative 4.4% over an equivalent cell packaged behind uncoated glass. This represents 50% recovery of the losses associated with packaging. Dual-layer antireflective coatings for both silicon and gallium arsenide solar cells using the silica nanoparticle coating were also created. An average increase of 28% in the short-circuit current and 32% relative improvement in device efficiency was achieved with silicon devices. The average conversion efficiency of the planar silicon cells was increased from 10.6% to 14% by addition of the coating. In summary, the experimental study of the optical properties and surface morphology of silica nanoparticle films deposited with a PVP adhesion layer demonstrated the potential of these films as optical coatings and functional self-cleaning and antifogging surfaces. The characterization of these silica nanoparticle films provided a fundamental understanding of the relationship between the optical and wetting properties of the nanoparticle coating and the morphology of the film

Antireflective coating for glass applications and method of forming same

One aspect of the disclosure is directed to a method for forming an antireflective coating on a substrate, which includes providing a polymer solution and a silica solution, depositing the polymer solution on a surface of the substrate to forming a polymer film thereon, depositing the silica solution on the formed polymer film on the substrate to form a silica film thereon, thereby forming a stack structure having the silica film formed on the polymer film that is, in turn, formed on the substrate, and drying the stack structure to form the antireflective coating on the substrate, wherein the antireflective coating comprises silica nanoparticles

Guest Editors Foreword

Consequently, African American males with LD are still significantly less than their White counterparts to matriculate through the post-secondary system and receive a college degree. (Newman et al., 2011). Banks and Gibson (2016) asserted “the under-representation of AA college students with disabilities in 4-year institutions underscores the need for systematic examination of school and non-school variables that influence students’ transition to college and retention during the college years.” (p. 71). However, the limited scholarship on the subject continues to leave many unanswered questions related to theory and experiential knowledge regarding AA males with LD in higher education (Robinson, Ford, Ellis, & Hartlep, 2016)

Enabling a High Throughput Real Time Data Pipeline for a Large Radio Telescope Array with GPUs

The Murchison Widefield Array (MWA) is a next-generation radio telescope currently under construction in the remote Western Australia Outback. Raw data will be generated continuously at 5GiB/s, grouped into 8s cadences. This high throughput motivates the development of on-site, real time processing and reduction in preference to archiving, transport and off-line processing. Each batch of 8s data must be completely reduced before the next batch arrives. Maintaining real time operation will require a sustained performance of around 2.5TFLOP/s (including convolutions, FFTs, interpolations and matrix multiplications). We describe a scalable heterogeneous computing pipeline implementation, exploiting both the high computing density and FLOP-per-Watt ratio of modern GPUs. The architecture is highly parallel within and across nodes, with all major processing elements performed by GPUs. Necessary scatter-gather operations along the pipeline are loosely synchronized between the nodes hosting the GPUs. The MWA will be a frontier scientific instrument and a pathfinder for planned peta- and exascale facilities.Comment: Version accepted by Comp. Phys. Com

Molecular targeting of protein arginine deiminases to suppress colitis and prevent colon cancer

Ulcerative colitis (UC) is a chronic disease, in which the lining of the colon becomes inflamed and develops ulcers leading to abdominal pain, diarrhea, and rectal bleeding. The extent of these symptoms depends on disease severity. The protein arginine deiminase (PAD) family of enzymes converts peptidyl-Arginine to peptidyl-Citrulline through citrullination. PADs are dysregulated, with abnormal citrullination in many diseases, including UC and colorectal cancer (CRC). We have developed the small molecule, pan-PAD inhibitor, Chlor-amidine (Cl-amidine), with multiple goals, including treating UC and preventing CRC. Building off our recent results showing that: 1) Cl-amidine suppresses colitis in vivo in a dextran sulfate sodium (DSS) mouse model; and 2) Cl-amidine induces microRNA (miR)-16 in vitro causing cell cycle arrest, we tested the hypothesis that Cl-amidine can prevent tumorigenesis and that miR-16 induction, by Cl-amidine, may be involved in vivo. Consistent with our hypothesis, we present evidence that Cl-amidine, delivered in the drinking water, prevents colon tumorigenesis in our mouse model of colitis-associated CRC where mice are given carcinogenic azoxymethane (AOM), followed by multiple cycles of 2% DSS to induce colitis. To begin identifying mechanisms, we examined the effects of Cl-amidine on miR-16. Results show miR-16 suppression during the colitis-to-cancer sequence in colon epithelial cells, which was rescued by drinking Cl-amidine. Likewise, Ki67 and cellular proliferation targets of miR-16 (Cyclins D1 and E1) were suppressed by Cl-amidine. The decrease in cell proliferation markers and increase in tumor suppressor miRNA expression potentially define a mechanism of how Cl-amidine is suppressing tumorigenesis in vivo

Potential role for PADI-mediated histone citrullination in preimplantation development.

BACKGROUND: The peptidylarginine deiminases (PADIs) convert positively charged arginine residues to neutrally charged citrulline on protein substrates in a process that is known as citrullination or deimination. Previous reports have documented roles for histone citrullination in chromatin remodeling and gene regulation in several tissue types, however, a potential role for histone citrullination in chromatin-based activities during early embryogenesis has not been investigated. RESULTS: In the present study, we tested by laser scanning confocal indirect immunofluorescence microscopy whether specific arginine residues on the histone H3 and H4 N-terminal tails (H4R3, H3R2 + 8 + 17, and H3R26) were citrullinated in mouse oocytes and preimplantation embryos. Results showed that all of the tested residues were deiminated with each site showing a unique localization pattern during early development. Given these findings, we next tested whether inhibition of PADI activity using the PADI-specific inhibitor, Cl-amidine, may affect embryonic development. We found that treatment of pronuclear stage zygotes with Cl-amidine reduces both histone H3 and H4 tail citrullination and also potently blocks early cleavage divisions in vitro. Additionally, we found that the Cl-amidine treatment reduces acetylation at histone H3K9, H3K18, and H4K5 while having no apparent effect on the repressive histone H3K9 dimethylation modification. Lastly, we found that treatment of zygotes with trichostatin A (TSA) to induce hyperacetylation also resulted in an increase in histone citrullination at H3R2 + 8 + 17. CONCLUSIONS: Given the observed effects of Cl-amidine on embryonic development and the well documented correlation between histone acetylation and transcriptional activation, our findings suggest that histone citrullination may play an important role in facilitating gene expression in early embryos by creating a chromatin environment that is permissive for histone acetylation

Connecting the Point(s), Hunts Point, Bronx, New York

Hunts Point is a notoriously over-planned neighborhood. As the exploration of recent plans on page 15 illustrates, Hunts Point has been both the beneficiary and victim of planning efforts that have left many in the community feeling over-surveyed with inadequate results to show for it. Our client made it clear from the beginning that the community did not need another plan to sit on a shelf. Therefore, the team chose to focus on small-scale, actionable interventions that could be implemented without significant capital outlays. To this end, we began by conducting an analysis of existing conditions, investigating both the physical and social landscape of Hunts Point in order to begin to identify opportunities for transformative action that can be taken on by local community groups. We interviewed experts within and outside the community. We engaged residents in community preference mapping, gaining valuable information about the key physical assets in the neighborhood, including an understanding of where local people felt safe or unsafe. Through this work, we identified a number of challenges and opportunities. Through decades of poor land use planning decisions, Hunts Point has become a community beset with vacant and underutilized land and buildings. We chose to look at this as an opportunity: physical space that is not being used to its full potential offers the basic unit for a process of reimagining. It can activate the potential of both the space itself and the community that lives and works around it. Lots and buildings also lend themselves to piecemeal intervention: they can be imagined in connection with one another as a network or tackled one by one — a community garden here, new housing there, a farmers’ market here, a community center there. They offer the opportunity for small-scale intervention that adds up to large-scale transformation. We conducted a vacant land survey in order to determine the scale of this resource and develop an up-to-date and accurate catalog of vacant spaces in the area — a data set we are making publicly available to community stakeholders who are looking to take real, concrete action around these spaces. As we began the broader community outreach portion of our research, it was with the question of how to activate the potential already existing within the community. We hosted a series of meetings in which we posed a question, first to a small Advisory Committee of key community stakeholders (see page 8), and then to a larger forum of community members. We wanted to know what they wanted to see done with the vacant land, anticipating that out of this work we would achieve at least two outcomes: concrete ideas for vacant space repurposing, and a larger narrative about the most immediate concerns for Hunts Point residents. To complement and quantify this research, we also conducted outreach around questions of connectivity. It is not enough simply to activate spaces in isolation — in fact, Hunts Point has some beautiful newly-created park spaces, but many are outside of a reasonable walking distance for most residents and require walking down industrial streets burdened with heavy truck traffic. We wanted to get a sense of how residents perceive access to existing park spaces in order to facilitate recommendations on improving connections to these amenities. Alongside this questionnaire, we conducted a GIS analysis showing the number of residents within a 5, 10 or 15 minute walk of each of the neighborhood’s parks. The connectivity survey also included questions about access to healthy and affordable food. Given that food access had come up throughout our research, we saw an opportunity to quantify residents’ perceptions of their access to food, while also developing a data product that we could share with those seeking to advocate for food-based projects within the community. To complement this survey, we aggregated information about food vendors in Hunts Point and compiled the data into an accessible and easy-to-use map. We’ve been able to produce a vision for the spaces and places that could be reimagined in order to transform Hunts Point into a place that better meets the needs of residents. We’ve also identified potential places to improve connectivity to neighborhood amenities, which are currently cut off from the rest of the community. And we’ve developed recommendations on what form the transformation of spaces could take, while developing datasets that can be used by others seeking to carry this work forward

The Impact of Urinary Urgency and Frequency on Health-Related Quality of Life in Overactive Bladder: Results from a National Community Survey

AbstractObjectivesOveractive bladder (OAB) is described as urinary urgency, with and without urge incontinence and usually with frequency and nocturia. Most attention to OAB's impact on health-related quality of life (HRQL), however, has focused on urge incontinence. The objective of this study was to evaluate the burden of OAB, specifically urinary urgency and frequency on HRQL.MethodsIn the National Overactive Bladder Evaluation Program (NOBLE), a computer-assisted telephone interview survey was conducted to assess the prevalence of OAB in the United States. Based on interview responses, respondents were classified into three groups: continent OAB, incontinent OAB, and controls. To evaluate the HRQL impact of OAB, HRQL questionnaires were mailed to all respondents with OAB and age- and sex-matched controls as a performed nested case–control study. Continuous data were compared using Student's t tests and analysis of variance with post hoc pairwise comparisons; results were adjusted for age, sex, and comorbid conditions. Multivariable regressions were performed to assess the impact of each urinary variable on symptom bother and HRQL.ResultsA total of 919 participants responded to the questionnaires (52% response rate) with a mean age of 54.2 years (SD 16.4 years); 70.4% were female and 85% were white. Continent OAB participants comprised 24.8% of the sample, incontinent OAB 18.3%, and controls 56.9%. In each regression analysis, urinary urge intensity accounted for the greatest variance for increases in symptom bother and decreases in HRQL.ConclusionsThe experience of urinary urgency has a significant negative effect on HRQL and increases symptom bother, an effect that, in this community sample, is greater than that of incontinence, frequency, or nocturia