MRI: Acquisition of a Multi-User X-ray Diffraction System for Advanced Materials Analysis

The University of Maine\u27s Laboratory for Surface Science & Technology (LASST) proposes to purchase a high performance X-ray Diffraction (XRD) system to provide critical information about the structural properties of materials at the atomic, molecular, and nanometer scale. The versatile instrument will be composed of an X-ray generator, X-ray mirrors and lenses, a hybrid monochromator, a high resolution goniometer and sample cradle, slits and collimators, a fast multichannel detector and Xe proportional counter, and a high temperature sample stage. Specific measurement capabilities of the XRD system will include phase analysis, high resolution reciprocal space mapping, pole figure analysis, rocking curve analysis, reflectometry, stress and texture analysis, and topography. State-of-the-art XRD capabilities will be especially valuable to research programs at LASST pertaining to (i) semiconductor gas sensor films and ceramic coatings, (ii) novel piezoelectric single crystals for acoustic wave devices and sensors, and (iii) mesoporous and nanoporous materials for chemical detection and chemical separation. Other materials research projects that will benefit from high resolution XRD analysis include microsystem components and bio-MEMS devices, biomaterials and protein structures, dielectrics for microelectronics, paper coatings, composite materials, nanoparticle probes, cement-based materials, zeolites, and metal catalysts. University of Maine researchers propose to acquire a state-of-the-art X-ray Diffraction (XRD) Materials Analysis System to investigate the structure of the surfaces of thin film coatings, sensors, and other materials being developed in their laboratory. Detailed information about atomic bonding in materials will enable development of next generation chemical sensors to detect toxic chemicals in the environment, novel protective ceramic coatings for ultra-high temperatures, improved high frequency electronic materials, and membranes for chemical detection and separation. This research will be conducted by UMaine undergraduates, graduate students, postdocs, visiting scientists, and collaborators from other colleges and universities, industries, non-profit research institutions, and Maine\u27s public schools. The system will be located in the Laboratory for Surface Science & Technology (LASST), an interdisciplinary research center that brings together UMaine expertise from physics, chemistry, electrical engineering, chemical engineering, and biological engineering to solve problems related to surfaces, interfaces, thin films, microdevices, and nanostructured materials. The proposed system, the only of its kind in the State of Maine, will be used in projects with Maine high-tech companies and several start-up companies incubated from LASST research in sensor technology. Educational outreach workshops and demonstrations will be used to teach technology concepts to the general public, middle and high school teachers, high school students, undergraduates, and graduate students participating in other NSF-funded training activities at UMaine

Synthesis and Accelerated Testing of Oxynitride Films for High Temperature Applications

NON-TECHNICAL DESCRIPTION:There is a critical need for new protective ceramic coatings that can operate in harsh environments with service temperatures in the 1000-1500oC range. These ceramic coatings must exhibit excellent heat resistance, chemical stability, fracture toughness and wear durability so they can be reliably be used in applications such high performance engines, shrouds, rotors, seals, slides, and bearings. A major problem is that conventional ceramic coatings crack and delaminate during thermal cycling in reactive gases at extreme temperatures. This project focuses on developing and testing Si-Al-O-N and Si-Zr-O-N thin film coatings and tailoring their properties to achieve high performance in terms of corrosion resistance, wear resistance, and fracture toughness. To efficiently test and evaluate the performance of the ceramic coatings in high temperature harsh environments, a microfabricated test platform is being developed, upon which the ceramic films are strategically deposited, to carry out accelerated testing under conditions that mimic those that are encountered during service. The project trains a graduate student and two undergraduate students in the areas of high temperature materials, thin film technology, and microfabrication, and K-12 students are being educated about high temperature materials science. Collaborations with industrial partners are being used to evaluate the effectiveness of the new coatings that are developed. TECHNICAL DETAILS:Ceramic thin film coatings that can withstand harsh environments with service temperatures of 1000-1500oC must exhibit excellent heat resistance, chemical stability, fracture toughness and wear durability. Conventional ceramic coatings crack and delaminate during service because of interdiffusion phenomena, chemical reactivity, and stress generation during thermal cycling in reactive gases at extreme temperatures. This project focuses on developing and testing SiAlON and SiZrON films that are precisely fabricated using magnetron sputtering and ECR-plasma-assisted e-beam evaporation. Nanoscale architectures are being investigated including gradient and multilayer compositions in order to achieve high performance in terms of corrosion resistance, wear resistance, and fracture toughness. To efficiently test and evaluate coating performance under thermal cycling conditions, a microfabricated MEMS test platform is being developed that consists of microheaters, temperature sensors, oxidation sensors, stress indicators, and microsliding fixtures. The project trains a graduate student and two undergraduate students in the areas of high temperature materials, thin film technology, and microfabrication, and K-12 students are being educated about high temperature materials science. Collaborations with industrial partners are being pursued to evaluate the effectiveness of the SiAlON and SiZrON coatings

MRI: Acquisition of a SQUID Magnetometer for Analysis of Advanced Materials

Technical Summary: Superconducting quantum interference device (SQUID) magnetometry is a non-destructive technique that reveals detailed information about the electron spin interactions in many types of materials. This project will involve a state-of-the-art SQUID magnetometer and Magnetic Property Measurement System (MPMS), which is a critical tool for characterizing several types of materials currently being investigated by researchers within the Laboratory for Surface Science & Technology (LASST) and other University of Maine (UMaine) laboratories. Specific measurement capabilities include DC and AC magnetic susceptibility, magnetoresistivity, van der Paaw conductivity, and Hall mobility. State-of-the-art MPMS capabilities will be especially valuable to several research programs at UMaine pertaining to (i) surface magnetism in nanoparticles, (ii) magnetic anisotropies in sedimentary rocks, (iii) electrical transport in physical and chemical sensing devices, (iv) optical properties of nanostructures in high magnetic fields, and (v) magnetic nanoparticle based biosensors. The MPMS will serve as a focal point for training undergraduates, graduate students, postdocs, and visiting scientists in magnetic materials, nanotechnology, biophysics, and materials science. This instrument is a critical tool for expanding the capacity of UMaine research into magnetic aspects of nanotechnology, biophysics, sensor technology, and materials science. As no SQUID magnetometer currently exists in the State of Maine, the instrumentation will provide access for research projects from interested parties throughout the state, including non-Ph.D. granting institutions and small Maine businesses. The instrument is relatively easy to operate and provides direct information on electron spin interactions, and thus it will be a powerful tool to teach physics and nanotechnology concepts to several different constituents participating in UMaine outreach activities, including K-12 students and teachers, the general public, under-represented groups, and industry partners.Layman Summary: Superconducting quantum interference device (SQUID) magnetometry is a non-destructive technique that reveals detailed information about the electron spin interactions in many types of materials. Knowledge of electron interactions in materials is extremely important in building the next generation of computers, electronics, and contrast agents in biological magnetic screening techniques (i.e. MRI). To gain the necessary information, a system with control over both the magnetic field strength and temperature is critical. To this end, a SQUID/Magnetic Property Measurement System (MPMS) is ideal for these measurements. This project will purchase a state-of-the-art MPMS system and will be especially valuable to several research programs at UMaine pertaining to surface magnetism in nanoparticles, magnetic anisotropies in sedimentary rocks, electrical transport in physical and chemical sensing devices, and magnetic nanoparticle based biosensors. The proposed MPMS will serve as a focal point for training undergraduates, graduate students, postdocs, and visiting scientists in magnetic materials, nanotechnology, biophysics, and materials science. As no SQUID magnetometer currently exists in the State of Maine, the instrumentation will provide access for research projects from interested parties throughout the state, including non-Ph.D. granting institutions and small Maine businesses. The instrument is relatively easy to operate and provides direct information on electron spin interactions, and thus it will be a powerful tool to teach physics and nanotechnology concepts to several different constituents participating in UMaine outreach activities, including K-12 students and teachers, the general public, under-represented groups, and industry partners

Acquisition of a Multi-User Thin Film Synthesis and Processing Facility

A state-of-the-art advanced materials synthesis and processing facility focusing on the growth and fabrication of ceramic- based thin film materials will be funded with the assistance of the Academic Research Infrastructure Program. The facility will include a multi-technique thin film materials synthesis chamber equipped with a microwave plasma source, effusion cells, electron beam evaporators, magnetron sputter sources, and a Kauffman ion source. Characterization capabilities will include in-situ reflection high energy electron diffraction (RHEED), mass spectrometry for controlling growth processes, X-ray photoelectron spectroscopy (XPS), and a novel Hall probe for in- situ film characterization. Three major areas of research will be impacted significantly by the facility, namely 1) solid state micro-sensors, 2) nanomechanics of materials, and 3) surfaces and interfaces in hetero-epitaxial oxide systems. In the sensor work, which has connections with local industry, the synthesis and processing of well-defined doped metal-oxide films will be developed with the goal of understanding and controlling the molecular scale mechanisms by which surface microstructure, dopant type, and operating temperature influence sensor performance. A broad based advanced materials synthesis and processing facility for the growth and fabrication of ceramic-based thin films will be operated for the study of solid state microsensors based on metal-oxide ceramic films. The nanomechanics of these ceramic thin films will be studied, as well as the surfaces and interfaces occurring in heteroepitaxial oxide systems

IGERT: Sensor Science, Engineering, and Informatics

This Sensor Science, Engineering and Informatics (SSEI) IGERT program will provide multidisciplinary doctoral training in the area of sensor systems ranging from the science and engineering of new materials and sensing mechanisms to the interpretation of sensor data. The design and management of effective sensor systems requires a holistic understanding of how information is collected, stored, integrated, evaluated, and communicated within sensing systems and to decision makers in diverse application contexts. The SSEI IGERT weaves together three research focus areas: (1) Sensor Materials and Devices, (2) Sensor Systems and Networks, and (3) Sensor Informatics. The intellectual merit of the project includes education and research activities that are designed to ensure a feedback loop so that SSEI IGERT trainees are able to transform new knowledge from sensor-generated data to further development of sensor systems and networks and advances in sensor materials and devices, and vice versa. Innovative components of the program include (1) development and use of a testbed prototype that will require interdisciplinary interaction across the three research areas; (2) a tight integration of the social, legal, ethical, and economic dimensions of sensing environments in both research and training, (3) expanded relationships with companies and federal laboratories engaged in sensor research, (4) international collaborations, and (5) synergistic integration with sensor science and engineering education at the middle, high school, and undergraduate level. The broader impacts of the SSEI IGERT program are a new breed of scientists and engineers who will be versatile in dealing with the diverse technical components that contribute to sensing systems, knowledgeable in the legal, social, and ethical contexts of heavily sensed environments, and aware of the human values that must be preserved, protected and promoted within such systems. IGERT is an NSF-wide program intended to meet the challenges of educating U.S. Ph.D. scientists and engineers with the interdisciplinary background, deep knowledge in a chosen discipline, and the technical, professional, and personal skills needed for the career demands of the future. The program is intended to catalyze a cultural change in graduate education by establishing innovative new models for graduate education and training in a fertile environment for collaborative research that transcends traditional disciplinary boundaries

The Role of Citizens in Detecting and Responding to a Rapid Marine Invasion

Documenting and responding to species invasions requires innovative strategies that account for ecological and societal complexities. We used the recent expansion of Indo-Pacific lionfish (Pterois volitans/miles) throughout northern Gulf of Mexico coastal waters to evaluate the role of stakeholders in documenting and responding to a rapid marine invasion. We coupled an online survey of spearfishers and citizen science monitoring programs with traditional fishery-independent data sources and found that citizen observations documented lionfish 1–2 years earlier and more frequently than traditional reef fish monitoring programs. Citizen observations first documented lionfish in 2010 followed by rapid expansion and proliferation in 2011 (+367%). From the survey of spearfishers, we determined that diving experience and personal observations of lionfish strongly influenced perceived impacts, and these perceptions were powerful predictors of support for initiatives. Our study demonstrates the value of engaging citizens for assessing and responding to large-scale and time-sensitive conservation problems

Influence of C-5 substituted cytosine and related nucleoside analogs on the formation of benzo[a]pyrene diol epoxide-dG adducts at CG base pairs of DNA

Endogenous 5-methylcytosine (MeC) residues are found at all CG dinucleotides of the p53 tumor suppressor gene, including the mutational ‘hotspots' for smoking induced lung cancer. MeC enhances the reactivity of its base paired guanine towards carcinogenic diolepoxide metabolites of polycyclic aromatic hydrocarbons (PAH) present in cigarette smoke. In the present study, the structural basis for these effects was investigated using a series of unnatural nucleoside analogs and a representative PAH diolepoxide, benzo[a]pyrene diolepoxide (BPDE). Synthetic DNA duplexes derived from a frequently mutated region of the p53 gene (5′-CCCGGCACCC GC[15N3,13C1-G]TCCGCG-3′, + strand) were prepared containing [15N3, 13C1]-guanine opposite unsubstituted cytosine, MeC, abasic site, or unnatural nucleobase analogs. Following BPDE treatment and hydrolysis of the modified DNA to 2′-deoxynucleosides, N2-BPDE-dG adducts formed at the [15N3, 13C1]-labeled guanine and elsewhere in the sequence were quantified by mass spectrometry. We found that C-5 alkylcytosines and related structural analogs specifically enhance the reactivity of the base paired guanine towards BPDE and modify the diastereomeric composition of N2-BPDE-dG adducts. Fluorescence and molecular docking studies revealed that 5-alkylcytosines and unnatural nucleobase analogs with extended aromatic systems facilitate the formation of intercalative BPDE-DNA complexes, placing BPDE in a favorable orientation for nucleophilic attack by the N2 position of guanin

Bayesian Inference in Processing Experimental Data: Principles and Basic Applications

This report introduces general ideas and some basic methods of the Bayesian probability theory applied to physics measurements. Our aim is to make the reader familiar, through examples rather than rigorous formalism, with concepts such as: model comparison (including the automatic Ockham's Razor filter provided by the Bayesian approach); parametric inference; quantification of the uncertainty about the value of physical quantities, also taking into account systematic effects; role of marginalization; posterior characterization; predictive distributions; hierarchical modelling and hyperparameters; Gaussian approximation of the posterior and recovery of conventional methods, especially maximum likelihood and chi-square fits under well defined conditions; conjugate priors, transformation invariance and maximum entropy motivated priors; Monte Carlo estimates of expectation, including a short introduction to Markov Chain Monte Carlo methods.Comment: 40 pages, 2 figures, invited paper for Reports on Progress in Physic

Routine Antenatal Anti-D Prophylaxis in Women Who Are Rh(D) Negative: Meta-Analyses Adjusted for Differences in Study Design and Quality

Background: To estimate the effectiveness of routine antenatal anti-D prophylaxis for preventing sensitisation in pregnant Rhesus negative women, and to explore whether this depends on the treatment regimen adopted. Methods: Ten studies identified in a previous systematic literature search were included. Potential sources of bias were systematically identified using bias checklists, and their impact and uncertainty were quantified using expert opinion. Study results were adjusted for biases and combined, first in a random-effects meta-analysis and then in a random-effects metaregression analysis. Results: In a conventional meta-analysis, the pooled odds ratio for sensitisation was estimated as 0.25 (95 % CI 0.18, 0.36), comparing routine antenatal anti-D prophylaxis to control, with some heterogeneity (I 2 = 19%). However, this naïve analysis ignores substantial differences in study quality and design. After adjusting for these, the pooled odds ratio for sensitisation was estimated as 0.31 (95 % CI 0.17, 0.56), with no evidence of heterogeneity (I 2 = 0%). A meta-regression analysis wa

Challenges in Ceramic Science: A Report from the Workshop on Emerging Research Areas in Ceramic Science

In March 2012, a group of researchers met to discuss emerging topics in ceramic science and to identify grand challenges in the field. By the end of the workshop, the group reached a consensus on eight challenges for the future:—understanding rare events in ceramic microstructures, understanding the phase-like behavior of interfaces, predicting and controlling heterogeneous microstructures with unprecedented functionalities, controlling the properties of oxide electronics, understanding defects in the vicinity of interfaces, controlling ceramics far from equilibrium, accelerating the development of new ceramic materials, and harnessing order within disorder in glasses. This paper reports the outcomes of the workshop and provides descriptions of these challenges