Stephen Wilson - US grants

Funds are requested for the purchase of a 300 MHz NMR (QE-300, Nicolet) spectrometer in order to improve and expand the research capabilities of NIH awardees in the Departments of Chemistry and Biology at New York University. The instrument will be housed and maintained in Chemistry Department space under the supervision of a Laboratory Manager familiar with Nicolet technologies. The most pressing need for the instrument is that of Professor Wilson who is confronted with small quantities of naturally occurring molecules or their synthetic precursors whose molecular architecture can only be understood with high-field NMR. Strong needs exist for the instrument by other faculty with NIH grants or applications that cover a broad range of health related projects such as DNA-carcinogen interactions, active-site inhibitors for GAR transformylase, cholecystokinin antagonists, dopamine analogues, metals in histidinol dehydrogenase and carcinogen-modified oligonucleotides.

This project involves the development of a number of new reactions and concepts for Organic Synthesis. The potential for our bisannulation strategy in the convergent synthesis of polycyclic molecules will be examined. New functionalized pentadienyl anions for intramolecular Diels-Alder reactions will be investigated. The synthesis of 25-hydroxy vitamin D will be carried out. Several routes to a taxane molecule suitably functionalized for further elaboration will be studied. The intramolecular Diels-Alder reaction of benzofurans will be investigated as a potential route to morphine.

The goal of this research is to explore the scope and stereochemistry of a set of reactions for the specific construction of C--C bonds in flexible or acyclic systems. These reactions involve homologation of Claisen, Carroll, and (2,3)-sigmatropic rearrangements and the Peterson olefination via intermedate allylsilanes. The bond construction and stereospecificity is maintained and extended so as to provide control over 1-2, 1-3, 1-4, and 1-5 relative asymmetric centers. Functionalized allylsilanes are produced which allow novel ring-forming reactions as well. Although the primary goal is to learn all that we can about the reactions in question, rather than to pursue total synthesis, the reactions will be investigated in the context of current synthetic problems such as the Prelog-Djerassi lactone, Boromycin, Phytol, Vitamin D, as well as alkaloids and terpenes.

Digital transmission of images implemented by VLSI is considered a very important area because of the possible reduction in the transmitted information rate subject to an acceptable level of error. Much of the research to the present time has been devoted to still-picture, or intraframe coding. Other work has been directed towards the interframe coding, or motion coding, task. In this investigation, both intraframe (still) image coding and intraframe (motion) image coding, with an objective of further bit rate reduction below presently known techniques, is pursued. This research involves vector quantization principles which are to be extended to color imagery and to temporal coding. The goal is to make the objective bit rate substantially lower than present levels. The first topic involves extending recent work in intraframe coding to color imagery and to lower bit rates. Coding of motion imagery by vector quantizing of the frame difference signals is also proposed, along with a simple classification scheme to process color imagery at rates of approximately one-third of the rate that now exists for standard videoconferencing coders.

New technology for the design of suicide inhibitors of cytochrome P-450 will be explored. Sulfur and silicon analogues of the substrates fo P-450 enzymes involved in critical biological roles will be synthesized and tested with purified enzyme systems, where possible. Inhibitors of P-450's will be targeted for cholesterol side chain cleavage, 11 Beta-hydroxylation, 17,20-lyase, aromatase, vitamin D3 1 Alpha-hydroxylase. Model compounds will be prepared and tested with liver microsomal P-450 in the Ames test. The proposal has four parts: 1) Studies relating to the mechanism and active site of P-450scc. 2) Mechanistic studies of proposed suicide chemistry. 3) The development of In vivo inhibitors. 4) Synthesis of potential suicide inhibitors of four other steroid hormone P-450's and microsomal P-450.

mass spectrometry; biomedical equipment resource;

Concious sedation is one conventional method of managing young, uncooperative children who have dental restorative needs. There are no well-controlled clinical studies which have systemically investigated the relationships between the variables of psychosedative agents, patient behavior, and multiple physiologic parameters during restorative procedures in pediatric dentistry. The propse of this study is to determine the effects of chloral hydrate (CH) on children's clinical behavior, heart rate (HR), blood pressure (BP), respiratory rate (RR), peripheral oxygen saturation (02), expired carbon dioxide (C02), frontalis electromyographic (EMG) and electroencephalographic (EEG) activity during routine restorative treatment. Three dosages of CH and a placebo will be studied. (CH) dosages will be 25, 50 and 75 mg/kg body weight. CH and the placebo will be administered per oris. The subjects of this pilot study will be 24 young (18-36 months of age), uncooperative children who are healthy, but present with caries in a minimum of four of the six quadrants (anterior and posterior). Four appointment periods will be necessary to complete their individualized treatment. The three dosage levels and placebo per group will vary in a Latin square design with each subject receiving three levels of CH and the placebo across four appointments. Fifteen patients will be assigned to each group constituting the four sequences of drug dosages and placebo in the Latin square design. The behavioral and physiologic responses of the child will be rated and recorded during five general phases (pre-opreative, topical anesthesia, injection of local anesthesia, rubber dam application and cavity preparation) respectively. The child will continue to be monitored post-operatively for 30 minutes or until they can be released to parental care. The operator and rater of the behavior will be "blinded" to drug and placebo. All children will have their teeth restored according to the usual and customary standard care at the clinic. ANOVA and Pearson Product Moment Correlation Coefficient will be used to determine: a) any significant dosage effect of CH and placebo on the physiologic parameters at each recording phase and b) any significant correlation among physiologic parameters, respectively. Chi square analysis will be used to evaluate behavioral response categories per dosage level of CH and placebo in each recorded phase.

9400666 This grant from the Organic Dynamics Program supports the work of Professors Schuster, Wilson, and Courtney at New York University to study the scope and mechanism of photocycloadditions of fullerenes by enones. The studies focus on an analysis for steric and electronic influences of the fullerene functionalizations, sensitizing and quenching experiments to address the reaction mechanism, and analysis of the interaction between the reactants by photophysical probes. Characterization of fullerene excited states and triplet 1,4-biradicals is sought by photosensitized electron transfer reactions and time-resolved photoacoustic calorimetry. In this project Drs. Schuster, Wilson, and Courtney will conduct photocycloadditions of fullerenes by a variety of enones. Their research provides a novel route to functionalize fullerenes and addresses in detail all parameters that influence the photochemical reaction pathway. The significance of their studies on fullerenes is a profound expansion of the important photocycloadditions of olefins. This research will also provide much valued information on the photochemical and photophysical properties of fullerenes.

9415996 Wilson This project investigates a recently described error control coding technique, called Turbo coding, which claims to significantly lower the signal-to-noise ratio required for reliable communication on the Gaussian noise channel, for still reasonable complexity. The research will study the baseline technique to corroborate the initial findings, and explore the sensitivity to such issues as interleaver design and constituent code complexity. Improvements which lessen the delay, memory, and computational requirements are under study, with the aim of making this concept truly practical in contemporary applications such as packetized wireless networks. Also under study is the extension of the basic coding ideas (component coding with iterative, interacting decoding) to lower rate schemes, with an attempt to get beyond the 0 dB barrier on Eb/No. A 'symmetric' form for the basic iterative decoder has been developed and is under study. More importantly, the concept will be extended to bandwidth efficient trellis coded modulation for the Gaussian channel, and to codes for Rayleigh fading channels. ***

Turbo coding is the conventional name given to an exciting and relatively new digital communication technique capable of approaching the theoretical limits imposed by Shannon theory. The technique has enjoyed enormous recent attention from coding theorists, but many practical, engineering-oriented issues remain before these coding techniques will see widescale practical implementation. We propose research in the areas of: (1) reduction of decoder latency and complexity; (2) developing stream encoder and decoder architectures; (3) efficient synchronization at low SNR; (4) improving performance of small-frame turbo systems; (5) robustness to channel modeling error, either in estimation of SNR or non-Gaussian noise; and (6) use of turbo codes on non-coherent or differentially-coherent channels.

The functonalization of C60 and C70 by means of a (2+2) photocyclization of cyclic enones onto the fullerene skeleton will be examined. The generality and chemoselectivity of the methodology will be developed through a selective use of different enones, and comparisons of the product distributions obtained with C60 and C70 fullerenes. Mechanistic details will be elucidated with particular attention paid to understanding why the high energy enone triplets prefer to undergo the chemical reaction with the fullerene skeleton, rather than energy transfer to a lower energy fullerene triplet state. Metalloporphyrins tethered to the fullerenes will be achieved by means of this photosynthetic methodology, and the photoinduced electron transfer between the tethered fragments examined. Graduate and undergraduate students will be involved in all aspects of the research including its presentation at scientific meetings. With this award, the Organic and Macromolecular Chemistry Program supports the research and educational activities of Professors Schuster and Wilson of the Department of Chemistry at New York University. Professors Schuster and Wilson will focus their research efforts on generalizing a photochemical methodology for functionalizing C60 and C70 fullerenes. Photophysical experiments will be undertaken to elucidate the mechanism of addition and the factors affecting the rate of chemical reaction with the fullerene skeleton relative to the rate of energy transfer. Professors Schuster and Wilson involve both graduate and undergraduate in all aspects of the work making the research and its presentation educational vehicles.

With this renewal award the Organic and Macromolecular Chemistry Program supports the work of Dr. David I. Schuster and Stephen R. Wilson in the Department of Chemistry of New York University in New York City. Part of the work is aimed at the synthesis and photophysical investigation of supramolecular complexes with a variety of rotaxanes and catenanes in which non-covalently linked metal porphyrin complexes and C60 fullerenes are held in unusual spatial relationships. It is based on earlier work with porphyrin-fullerene dyads connected by flexible polyether or rigid steroid linkers. Other studies will involve [2+2] photocycloaddition of cyclic enones to C70, and the synthesis, photochemistry and self-assembly of fullerene derivatives with highly fluorinated molecular tails.

Most of the work involves the synthesis and study of molecules which contain both an electron donor (a metal (usually zinc) porphyrin complex), which can be readily put into an electronically excited state using light, and an electron acceptor (a ball of 60 or 70 carbon atoms), to which an electron can be transferred after the donor has been excited. The process mimics the first step of photosynthesis in green plants, which use a magnesium porphyrin complex to absorb light, followed by electron transfer. The novel molecules to be studied will shed light on the details of the electron excitation and transfer process, and could eventually lead to novel optical and electronic materials. Because the work involves synthesis, characterization, photochemistry, photophysics, and computational design, it is expected to provide excellent training for the students involved.

Chemistry (12)

This award is providing a dedicated molecular modeling Linux Cluster for use across the chemistry curriculum, including the integration of molecular modeling modules in honors freshman chemistry, honors organic, and experimental physical chemistry. A new computer laboratory course, Computational Nanotechnology is providing undergraduate chemistry students and other science majors an exposure to modern research techniques and emerging scientific are as. Computational Nanotechnology is training a new generation of skilled workers in the multidisciplinary approaches necessary for continued progress in
nanotechnology and is providing significant laboratory research experience. In this course, students are designing, building, and testing molecular devices, materials, and nanostructures adapted from the research and educational literature, including organic and protein-based molecular motors, surface interaction and self-assembly, and molecular dynamics simulations.

Space-Time Coding for Optical MIMO ChannelsStephen G. Wilson and Maite Brandt-PearceDept. of Electrical and Computer EngineeringUniversity of Virginia, Charlottesville, VA 22906Phone: (434) 924-6091, (sgw,mb-p)@virginia.eduAbstract:

Free-space optical links are an emerging technology for wideband access to networks because of the tremendous bandwidth potential they offer. Outdoor atmospheric channels are hampered by signal fading effects due to particulate scattering in a line-of-sight path, clear-air turbulence, or merely static index-of-refraction inhomogeneities. Similarly, indoor IR systems are faced with fading arising from the intrinsic multipath environment. One powerful method of improving the performance of wireless communication systems is through the use of transmit and receive antennas, creating a so-called multiple-input/multiple-output (MIMO) channel. MIMO channel models, provided by transmit and receive antenna arrays, have attracted enormous attention for RF wireless systems in the past five years, owing to the very large potential throughput in bits/second/Hertz and increased protection against fading associated with single antenna designs.

This research addresses the design and performance analysis of space-time codes that can be applied to MIMO channels for application to the wireless optical communications environment. The research focuses on several aspects of this problem:

--development of relevant MIMO models for outdoor line-of-sight optical channels, with particular attention to modeling of source and detector physics; --examination of the information-theoretic potential of this channel, particularly in the context of growing array size, and the analysis of bounding techniques on error probability to aid in the development of code design rules; --formulation and evaluation of space-time coding approaches for the optical free-space regime that are efficient in the channel capacity sense;
--block-coded, trellis-coded, and concatenated approaches.

Also, the application of space-time codes to the indoor wireless infrared channel and the examination of their performance are addressed.

Chemistry (12)

The laboratory curriculum for chemistry majors is being restructured with a focus on inquiry-based experiments in the areas of modern chemical research. Three major educational goals are being addressed: (1) stimulating student interest in chemistry through projects in contemporary chemical issues; (2) providing students with the opportunity to apply modern instrumentation in experimental investigations; and (3) fostering collaborative interaction among students across different courses in the laboratory sequence.

A sequence of three laboratory courses is being implemented to fill the niche in the undergraduate curriculum normally occupied by second semester organic, advanced inorganic, and physical chemistry laboratories. These courses are emphasizing modern themes from contemporary chemistry research and development and include topics in nanotechnology, combinatorial chemistry, chiral technology, and biophysical chemistry. Seven topic modules were developed that emphasize these themes and seventeen experiments from the research and educational literature are now being adapted and implemented across the three courses. Thus, the courses are "integrated" thematically if not experimentally, and this is enhancing the interest and motivation of students as they proceed from one course to another in the sequence. Modern, high-quality instrumentation and equipment is available for use by undergraduates in these courses. Students in a prerequisite course are collaborating with students enrolled in advanced courses of the sequence. For example, students in a module focussed primarily on synthetic chemistry are providing samples to students in advanced modules for product characterization or to perform experiments of a more physical nature requiring a more extensive theoretical background. Such cross-course collaborations emulate interactions between investigators working in different sub-disciplines of chemistry.

This Small Business Innovation Research (SBIR) Phase II project will involve production and purification of a powerful Magnetic Resonance Imaging (MRI) contrast agent based on a newly discovered nanomaterial (Trimetasphere), consisting of a metallic nitride nanocluster inside a fullerene type cage. Trimetaspheres recently demonstrated a factor of 21 times improved relaxivity over currently used MRI contrast agents. The project will involve designing and building a powder-feed continuous reactor, including large rod capability, developing chemically-based separations techniques and optimizing heat treatment of the chemically separated Trimetaspherses mixtures. The nanoproduction and chemical-based separations techniques for these Trimetasphere nanomaterials will provide the basis for the large-scale production of the Trimetasphere based MRI contrast agents.

Commercially, these Trimetaspheres have tremendous medical applications that will benefit US citizens with better medical care through improved diagnostics, new pharmaceuticals, and simultaneous diagnostic and treatment reagents, at a fraction of current cost. The development of more sensitive contrast agents, if translated into smaller, less expensive MRI instruments, will open entirely new markets for the equipment manufacturers.

DESCRIPTION (provided by applicant): Background: This proposal will provide training to conduct research to understand racial disparities in tobacco-associated morbidity among children. Exposure to environmental smoke tobacco (ETS) remains a major public health hazard for children. Although African Americans are reportedly exposed to less ETS, they have disproportionately higher rates of asthma, low-birth weight, sudden infant death syndrome and higher levels of pre-cancerous compounds known as DMA adducts. Few studies have attempted to explain racial differences in DNA adducts by accounting for both environmental and genetic factors in children. Objectives: The objectives of this proposal are: 1) to examine the longitudinal relationship between ETS exposure and white blood cell (WBC) DNA adducts; 2) to test for racial differences in the level of WBC DNA adducts; 3) to determine whether polymorphisms in key genes explain the relationship between African American race and levels of WBC DNA adducts. Methods: This proposed project will use prospectively collected data and biologic samples from an NIH-funded asthma intervention trial. Using objective measures of ETS exposure and a 32P-postlabeling technique to measure levels of WBC DNA adducts, we will delineate the longitudinal relationship between children's ETS exposure and the formation of WBC DNA adducts. To understand how genetic polymorphisms influence racial differences in DNA adducts, we will explore whether polymorphisms in 4 candidate genes (GSTM1, GSTT1, GSTP1, and NAT2) modify the relationship between African American race and WBC DNA adducts. Training: To achieve the goals outlined in this proposal, I plan to pursue additional training in molecular epidemiology, cancer prevention, and advanced research methods. This training - coupled with mentorship from Drs. Bruce Lanphear and Robert Kahn and expertise from other advisors with extensive topical expertise - will prepare me to conduct inter-disciplinary research on the complex relationship of genetic predisposition and environmental exposures on children's health. Implications: The long-term goals of this training award will include a series of independently funded efforts to explore the effects of other polymorphisms on DNA adducts, and to test interventions that reduce DNA adduct levels in tobacco-exposed children.

ECS-0636598
M. Brandt-Pearce, University of Virginia

Our society's demand for wireless bandwidth is clearly increasing at a rapid rate, yet our radio frequency resources are all but depleted. This seeming impasse can be resolved by communicating over the wireless optical domain with its nearly boundless bandwidth, using an RF link as a backup. The objective of the proposed research is to use channel modeling and adaptive modulation/coding to unleash the synergy between the two technologies, relying on multiple parallel links (multiple-input multiple-output, MIMO) to provide the needed throughput and diversity. This is a collaborative effort between UVa and L-3 Communications, Communications Systems-West. The work is approached as five overlapping tasks performed by the three PIs and two graduate students. The communication theory behind a hybrid FSO/RF system will be developed, including the acquisition of channel state information. Data showing the correlation between channels will be collected. Adaptive modulation and coding techniques for simultaneous MIMO RF and optical links will then be designed and tested on realistic implementations.

Intellectual Merit:
The results of the proposed work will be to understand the relation between the optical and RF wireless channels and to improve their concurrent use for transmitting broadband information. The technique proposed is unique in that it relies on simultaneous communications over the two technologies, which is rarely done. The synchronized multi-channel data collected will add to the general knowledge of communication channels. The PI's have combined experience designing and evaluating optical and RF wireless systems, and MIMO systems in both technologies.

Broader Impact:
The proposed research enhances the performance and availability of wireless links through better system modeling, modulation, coding, and channel state estimation. These techniques will be made available to other researchers in the field through dissemination at international conferences and in journals. The increase in wireless connectivity will stimulate economic growth, especially in urban areas that are often difficult to serve using new fiber. Both graduate and undergraduate students will participate in this multifaceted research project. Students from diverse backgrounds will be sought.

"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)."

The objective of the research is to improve the distance-throughput product of ultraviolet communication systems by several orders of magnitude so that they may be used as inexpensive short-distance non-directed links, such as for voice and data. The approach taken combines a mix of communication-theoretic methods (modulation, coding, multi-beam transmission) and improved UV technologies (fine-tuned optics, powerful electro-optic devices) to obtain this gain. The research culminates in the development of an experimental testbed demonstrating and validating the concepts.

The novel contribution of this work is the blending of advanced communication techniques with clever optics to improve the link quality and make it suitable for a variety of applications. Previous research efforts have been one-dimensional, focusing on the devices, the physics, or the modulation, and exclusively for military applications. Commercial applications require significantly higher capacity and reliability, and multiple simultaneous users. This research provides a systematic plan for accomplishing this goal, starting with a mathematical description of the channel and ending with a prototype system.

A substantial improvement of the throughput and reliability of ultraviolet communication systems can lead to increased economic and scientific interest in this relatively immature technology. One can envision an explosion of applications currently unserved by inexpensive technology, such as the last-mile broadband connectivity in urban areas, densely-packed wireless sensor networks, and military applications. The research also provides a practical and stimulating medium for the education of graduate and undergraduate students. Undergraduate students of diverse backgrounds are used to design, develop and manage the experimental testbed.

DESCRIPTION (provided by applicant): Primary progressive aphasia (PPA) is a clinical syndrome in which degeneration of language regions in the dominant hemisphere is associated with progressive deficits in speech and/or language function. The overall goals of this project are to use functional magnetic resonance imaging (fMRI) to investigate neural changes underlying linguistic deficits in PPA, and to use this information to better discriminate patients with variants of PPA from each other and from normal aging. Recent studies have identified three clinical variants of PPA: progressive non-fluent aphasia (PNFA), semantic dementia (SD) and logopenic progressive aphasia (LPA). Each variant is associated with characteristic linguistic features, distinct patterns of brain atrophy, and different likelihoods of particular underlying pathogenic processes, making correct differential diagnosis highly relevant. We will recruit 48 patients with PPA (16 of each variant) and 24 normal controls over a three year period, and acquire fMRI data along with structural MRI, linguistic and cognitive measures. The fMRI paradigm consists of a syntactic processing task with seven conditions parametrically varying in syntactic complexity. The research will address two specific aims. The first is to identify the relationships between volume loss, changes in functional MRI activation, and linguistic deficits, in the different PPA variants. The second aim is to improve differential diagnosis of PPA variants using machine learning algorithms incorporating both structural and functional imaging measures. PUBLIC HEALTH RELEVANCE: PPA is a devastating disorder that prevents individuals from communicating and functioning in society. The knowledge gained in this study will increase our understanding of the neural basis of language processing and its breakdown in PPA, and will contribute to earlier, more accurate differential diagnosis of PPA variants, enabling emerging therapies to be targeted to likely underlying etiologies.

Non-Technical Abstract:
The electrons in a number of recently discovered materials with exciting new properties tread a fine line between two extremes: one of independent electrons largely ignoring one another (such as in good metals) and one where electrons interact so strongly with each other that they foster collective behavior. These new classes of so-called intermediate bandwidth systems occupy a unique regime where the coupling between an electron's atomic orbital motion and its intrinsic magnetic field (or spin) plays an important role in generating new electronic behavior. This project will support a neutron scattering-based experimental research program exploring the fundamental electronic behavior in three key classes of these new spin-orbit coupled materials: iron-based high temperature superconductors, iridium oxide insulators, and topological insulators; many of which possess potential for future energy transport and computing applications. The project will also support the growth of materials necessary to attack key research problems while simultaneously addressing the large national need for creative materials exploration. In addition to supporting the education of two PhD students, the project will also provide hands-on, research-based, education to underrepresented high school interns and undergraduates. The synergy fostered by this project's integration of research and educational activities will also advance a broader goal of training the next generation of neutron scattering experts in the United States.

Technical Abstract:
This award will support a neutron scattering-based experimental research program whose goal is to understand magnetism and competing order's role in the electronic behavior of an emerging class of intermediate bandwidth materials where strong spin-orbital coupling effects conspire to create novel properties. These materials occupy a unique coupling regime (U~W) where modest correlation can exert a dramatic influence within their resulting ground states. This project will focus on three classes of these materials where magnetic and orbital degrees of freedom are thought to play a key role: iron pnictide high temperature superconductors, novel 5d Mott insulators, and perturbed topological insulators. Work will be guided by the project-supported growth of the crystalline materials necessary to attack key issues while simultaneously addressing the large national need for creative materials exploration. In addition to supporting the education of two PhD students, the project will also provide hands-on, research-based, education to underrepresented high school interns and undergraduates. The synergy fostered by this project's integration of research and educational activities will also advance a broader goal of training the next generation of neutron scattering experts in the United States.

Data networking via satellite relays remains an important means of linking globally-distributed network terminals for both commercial and governmental applications, especially in remote regions. Modern applications demand both spectrum and power efficiency in the network. The archetype network model in such networks is one with two terminals wishing to exchange data via a single satellite transponder. Relative to traditional time-sharing or frequency-sharing for the bidirectional communication paths, information-theory reveals that spectrum efficiency gains of up to 100% can be obtained for a given set of link power resources. These gains are possible when non-orthogonal transmission methods are adopted, and the decoders exploit side-knowledge on previously-transmitted information.

The project codifies various protocols appropriate to this two-terminal data exchange model, including amplify-forward, as well as protocols that involve satellite decoding/re-encoding. The possible gains depend on link resources as well as the desired bidirectional rate targets. Existing research for this problem presumes perfect synchronization and side-information at both terminals, but practical issues of large round-trip delay, carrier phase/frequency synchronization, and symbol synchronization are important obstacles to achieving the promise of information theory. So the investigators develop realistic synchronization protocol designs that approach the ideal information-theoretic limits. In addition, the project studies a new decode-and-forward relaying protocol based on nested LDPC coding on downlinks that is flexible in terms of rate-asymmetry.

Measurements of the physical properties of materials at ultralow temperatures are key to discoveries in condensed matter physics, the science of new and emerging materials, and future technologies, such as quantum computing and new detectors. The Major Research Instrumentation program supports the acquisition of a versatile dilution refrigerator system with an integrated magnetic field capability for an interdisciplinary, multi-user facility at the University of California, Santa Barbara (UCSB). The system will be housed in the Low Temperature Facility at UCSB, which already serves a diverse and interdisciplinary user community. It will be available to all members of the University community, to researchers at other academic institutions, and to industry throughout Southern California and beyond. The instrument will greatly expand the training opportunities for graduate and undergraduate researchers, who are the primary hands-on users. Both formal (course work) and practical training will be provided, while the facility's staff will be responsible for student training, safety, day-to-day oversight, and routine maintenance. In addition to its central role in the training of the next generation of scientists and engineers, the dilution refrigerator will be ideally suited for undergraduate design and research projects, and serve to expose undergraduate researchers to low temperature science and measurement techniques.


The instrument addresses critical needs in materials characterization at ultra-low temperatures within a wide range of interdisciplinary research programs at UCSB that focus on low-dimensional materials, quantum computing, the realization and discovery of new quantum phenomena and phases, the development of new measurement techniques, and the characterization of the electronic structure of low-mobility materials. The Low Temperature Facility at UCSB already serves a diverse and interdisciplinary user community, who will have access to the dilution refrigerator system. The dilution system takes advantage of recent developments in technology that greatly facilitate its operation as a multiuser facility. These include recent advances in pulse-tube technology, allowing for cryogen-free and fully automated operation. The system is load-locked, which increases the number of samples that can be analyzed per instrument time. These features facilitate accessibility and ease of operation, dramatically reduce maintenance and operating costs, and allow for a high throughput of samples.

Nontechnical Abstract:
The goal of this project is to study the electronic and structural properties of crystalline materials found at a new frontier of condensed matter physics, one where materials possess both an appreciable interaction between electrons in tandem with a strong coupling between their inherent magnetism (spin) and their orbital motion. This unique combination of energy scales is predicted to stabilize fundamentally new states of electronic matter, ranging from new forms of superconductivity to new quantum entangled states with far-term applications potential in quantum computing. Research supported by the project focuses on understanding the materials pathways necessary for realizing these new states and on exploring the interactions responsible for driving the prototypical parent state of these materials - the spin-orbit Mott phase - from an insulator into a metal. Supported activities work to train the next generation of scientists utilizing national neutron and x-ray user facilities as well as work to address the nation's growing deficit in new materials discovery/synthesis by supporting the growth of new crystalline materials. The project provides research experience to undergraduates from underrepresented demographics through summer research internships as well as conducts outreach activities aimed at inspiring precollege students to pursue materials science/physics academic and career pathways.

Technical Abstract:
The project focuses on experimentally exploring the mechanisms through which new classes of spin-orbit Mott (SOM) materials are driven from their parent insulating states into the metallic regime via carrier/bandwidth tuning. The insulating phases of SOM systems are inherently driven by a delicate interplay between strong spin-orbit coupling, crystal field, and short-range Coulomb interactions. This unique balance of energy scales in SOM compounds is predicted to host nearby exotic ground states ranging from high temperature superconductivity, to novel forms of quantum spin liquids, to correlated topological phases. Models of these new phases place them within close proximity to the parent SOM state. The primary goal of the project is to understand how interactions evolve once this parent state is destabilized and driven into nearby materials phase space - specifically, to resolve the role of electron correlations and the evolution of electronic and structural degrees of freedom as the metallic state is approached. Searching for new states/phase behaviors beyond the melting of the spin-orbit Mott phase is a second, overlapping goal of the supported research. Research activities are comprised of a combined materials synthesis, bulk electron properties characterization, and neutron/x-ray scattering effort aimed at forming a comprehensive picture of interactions in perturbed SOM states in classes of Ruddlesden-Popper, pyrochlore, and geometrically frustrated iridates. Students at the graduate and undergraduate levels will be trained in materials synthesis techniques as well as in the use of neutron and x-ray scattering at national user facilities, helping to build the core of the next generation of the national user community.

Non-technical Description: The world has seen an enormous increase in computing power, but the current path forward for the semiconductor industry is beset with roadblocks. A different strategy for a future generation of electronic devices is based on materials that exist in multiple electronic states. A new generation of electronic materials are required for this purpose, as are the means for switching between multiple electronic states. The fundamental science that is the focus of this project is centered on the sudden change in the electrical properties of certain materials when they are switched through a so-called metal-to-insulator transition by an external trigger. On one side of the transition, the material behaves like copper metal, while on the other side, it behaves like insulating wood. The project goal is to design and discover materials exhibiting such metal-to-insulator transitions that enable room-temperature operation and that display large changes in the key property of interest; the electrical resistivity. The strategy is to control properties by structural design at the atomic scale. The approach employs a tightly integrated combination of experiment, theory, and data-mining of the literature, that would enable new insights to emerge and aid in the design of desirable materials. This project will deliver a research workflow with a suite of tools to enable assessment and experimental validation of new concepts for the discovery of key materials. The project will articulate protocols for selecting high-performing materials, leading to an expanded palette of compounds that could impact future technologies. The teaching and training of students and the discovery capabilities of the project are interwoven, and aimed at broadening participation through the involvement of the investigators and their group members in public outreach events. The development of modules for undergraduate and graduate courses and the involvement of students in interdisciplinary team environments are intrinsic to project plan. The project will yield a plethora of new and mined data on a range of oxides and new computational materials approaches. These will be aggregated into open-access databases on public portals.

Technical description: This project will pursue discovery of the atomic-level genetic code of materials displaying metal-to-insulator transitions through approaches that establish links between unit cell level crystal structure and the macroscopic electronic response, profiting from a coupling of theory, data, and comprehensive experimentation. At the present time, the essential data and structure-electronic function relationships to decipher the genetic code (generic descriptors) of metal-to-insulator transitions do not exist in a format which permits predictive synthesis. The project?s significance is that it recasts the problem into one of atomic structure, focusing on the role of different kinds of structural distortions, notably, breathing modes, Jahn-Teller distortions, and Peierls-like instabilities across a broad range of structure types and chemistries. The project will generate and collect a range of data that will permit the mapping of electronic interactions into atomic features, applying informatics-based methods to enable supervised and unsupervised learning. The project will articulate predictive rules and protocols for selecting high-performing materials, leading to an expanded palette of compounds that could impact technologies beyond electronics. The teaching and training of students at multiple levels and the discovery capabilities of the project are interwoven and aimed at broadening participation by through public outreach events, through the development of modules for undergraduate and graduate courses; and finally, by involving students in interdisciplinary team environments. The project will yield a plethora of new data on a range of oxides and new computational materials approaches. These will be aggregated into databases on public web-portals using a new portable file format designed for materials data. New methods of data visualization will allow external users to interact, query, and analyze the data for aims beyond those proposed herein. Data-driven models and informatics workflows for generating quantitative models for metal-to-insulator performance will be hosted with the aforementioned data and visualization tools on the MIST: Metals and Insulators by Structural Tuning platform. The PIs also plan to release MIST as open source and build a user community around the platform by ensuring that interested researchers are able to contribute to the MIST codebase. This will allow a wider growth of the project. This aspect is of special interest to the software cluster in the Office of Advanced Cyberinfrastructure, which has provided co-funding for this award. Advances in synthesis, theory, and characterization will strengthen the scientific capabilities and workforce by allowing students and academic or industrial researchers to employ the formulated structure-property relationships for educational and research purposes.