Division Of Materials Research Research Articles

Division of Materials Research: Topical Materials Research Programs (NSF)

Division of Materials Research: Topical Materials Research Programs (NSF)

A DFT+U Study of the Electrochemical Oxidation of H2 and CO on SrLaFeO4-Δ

INTRODUCTION Solid oxide fuel cell (SOFC) anodes are commonly composed of cermet materials, typically Ni-YSZ. Despite success in electrochemical performance, cermet materials suffer from sulfur poisoning, coke formation under low operating temperatures, and metal coarsening. Due to success of material design focused on the cathode such as LSCF, single-phase mixed ionic-electronic conducting (MIEC) materials have displayed promising oxidation activity [1]. The Sr-based Ruddlesden-Popper (RP) family has found recent use as a base stoichiometry in anodes where experimentalists have used both A and B-site doping and nanoparticle exsolvation strategies in order to tune activity [2,3]. In order to understand the fundamental electrochemical activity, we want to elaborate on the mechanism of H2 and CO oxidation on the promising material SrLaFeO4- \U0001d6ff (SLF). In the present study, we used ab initio methods to model H2 and CO oxidation on two FeO2-based models of SLF with and without B-site doping with Co and Ni. COMPUTATIONAL DETAILS All calculations presented in this work were performed using the spin-polarized DFT+U method with periodic boundary conditions as implemented in the VASP 5.4.4 code. We choose the PBE functional to describe exchange and correlation effects. Dudarev’s approach for DFT+U calculations is used with a U-J value of 4.0, 3.32, and 6.2 eV, respectively. We used the projector-augmented wave (PAW) method to represent the inner core potentials. The kinetic energy cutoff was set for all calculations to 700 eV, and integration over the Brillouin zone was performed with 3 × 3 × 1 Monkhorst-Point k-point mesh and the Gaussian smearing method with a sigma value of 0.05 eV. Slab models utilized a 15 Å vacuum layer and the bottom two layers were fixed to bulk position values. The DFT-derived parameters were employed in a microkinetic model to calculate the surface coverage of all adsorbed species for a given reaction condition. RESULTS AND DISCUSSION To begin our study, we tested all non-symmetrical conformers of SLF for the lowest relative energy on a model 2 × 2 × 1 supercell, as displayed in Figure 1a. A total of 3 structures were tested – P4/mmm, P4/nmm, and I4mm. We confirm that the lowest energy structure (I4mm) is equivalent to the experimentally reported structure. Next, we develop two 1.5 × 1.5 × 1 non-identical (001) FeO2-based slab models – so-called FeO2-LaO and FeO2-SrO (Figure 2b). The oxidation mechanism of H2 suggests oxidation begins with a dissociative adsorption step. Subsequent steps include formation of surface H2O, a surface vacancy, and a subsurface vacancy. To complete the catalytic cycle, we computed the bulk vacancy migration of SLF and assumed fast cathode kinetics for the overall cell model. At an operating voltage of 0.7 V, we predict that the highest rate occurs on the FeO2-SrO surface. We predict that H2 dissociative adsorption step is the rate-determining process based on Campbell’s degree of rate control. With the application of a single B-site dopant (Co and Ni), Co and Ni both decrease the barrier of the H2 dissociative adsorption step. Ni causes a slight decrease in energy for the formation energy of H2O. The oxidation mechanism of CO suggests oxidation begins with adsorption of the CO molecule on a reduced Fe site. The CO migrates to a neighboring Fe-O complex in order to form surface CO2. Based on degree of rate control, CO2 formation is likely the rate-determining step for both surface models.In conclusion, this is one of the first mechanism investigations on the anodic oxidation reactions of H2 and CO on RP-based oxides. We find that H2 has promising catalytic performance similar to the experimental evidence. The inclusion of B-site dopants displays that catalytic performance can be tuned with the introduction of different transition metals. Future work will examine the role of exsolved particles for RP-based oxides. ACKNOWLEDGMENTS This work has been funded by the Division of Materials Research, a National Science Foundation organization under Award Number 1832809. Computing resources provided by the San Diego Supercomputer Center (SDSC) and Texas Advanced Computing Center (TACC) under XSEDE grant number TG-CTS090100 and USC High-Performance Computing clusters are gratefully acknowledged. REFERENCES L. Xu, Y. Yin, N. Wang, Z. Ma, Electrochem. Commun., 76, 51–54 (2017)N. Wu, W. Wang, Y. Zhong, G. Yang, J. Qu, Z. Shao, ChemElectroChem, 4, 2378–2384 (2017)H. Chong, H. Chen, Z. Shao, J. Shi, J. Bai, S. Li, J. Mater. Chem. A, 4, 13997–14007 (2016) FIGURE 1a: 2×2×1 supercell model of I4mm SrLaFeO4 FIGURE 1b: Slab models of (001) FeO2-LaO and FeO2-SrO Figure 1

Division of Materials Research—Topical Materials Research Programs (NSF)

Federal Grants & ContractsVolume 45, Issue 17 p. 1-2 Grants alerts Division of Materials Research—Topical Materials Research Programs (NSF) First published: 29 July 2021 https://doi.org/10.1002/fgc.31860Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume45, Issue175 August 2021Pages 1-2 RelatedInformation

A DFT+U Study of the Oxygen Defect Formation in (Sr1-xPrx)2FeO4

INTRODUCTION Solid oxide fuel cell (SOFC) electrodes are commonly composed of cermet materials, a composite of ceramic and metal materials. Despite success in electrochemical performance, cermet materials suffer from sulfur poisoning at the triple-phase boundary (TPB), high operating temperatures, and metal coarsening. To mitigate these problems, single-phase mixed ionic-electronic conducting (MIEC) materials have been investigated as alternative electrode materials. One such class of materials is the Ruddlesden-Popper (RP) phase (An+1BnO3n+1), a perovskite composed of n layers of octahedra in a perovskite (ABO3) stack. The RP family of Srn+1FenO3n+1 has found recent use as a base stoichiometry in both cathodes1 and anodes2 with and without A-site trivalent dopants. In order to rationalize the design of RP electrodes, we elaborate on the relationship of MIEC properties as a function of A-site dopant concentration at the atomistic level. In the present study, we used ab initio methods to investigate the relationship between Pr3+ concentration, iron oxidation state, and charge compensation upon defect formation to better understand the role of the A-site on the ionic and electronic properties in (Sr1-xPrx)2FeO4± \U0001d6ff (x = 0, 0.125, 0.25, 0.375, 0.5). COMPUTATIONAL DETAILS All calculations presented in this work were performed using the spin-polarized DFT+U method with periodic boundary conditions as implemented in the VASP 5.4.4 code. We choose the PBE functional to describe exchange and correlation effects. Dudarev’s approach for DFT+U calculations is used to correct the inadequate description of localized 3d electrons on Fe and 4f electrons on Pr with a U-J value of 4.0 and 6.0 eV, respectively. We used the projector-augmented wave (PAW) method to represent the inner core potentials. The kinetic energy cutoff was set for all calculations to 750 eV, and integration over the Brillouin zone was performed with 5×5×3 Monkhorst-Point k-point mesh and the tetrahedron method with Blöchl corrections. RESULTS AND DISCUSSION To sample all possible structural conformations at a given dopant concentration, we tested all non-symmetrical conformers for the lowest relative energy on a model 2×2×1 supercell, as displayed in Figure 1a. A total of 7, 42, 123, and 181 structures were tested for each dopant configuration, respectively. We calculate metallic behavior for x = 0.125 and 0.25 and semi-conducting behavior for x = 0, 0.375 and 0.5, indicating electronic conductivity decreases upon increasing A-site dopant concentration. Figure 1b displays the relationship between the final optimized dopant configurations and defect stability. The interstitial formation energy decreases linearly with Pr concentration with a deviation at x = 0.125. This relationship is primarily a function of the neighboring cation elemental identity and the decreasing interatomic distance between the interstitial defect and the neighboring cations in the rocksalt regime. The vacancy formation energy appears constant with Pr except for a large energy penalty at x = 0.5. The origin of the harsh energy penalty is rooted in the over-reduction of Fe. Upon vacancy formation, the released electrons directly reduce the next-nearest Fe atoms from +3 to +2 as opposed to delocalizing upon the oxide lattice. Figure 1c displays the relationship between the degree of delocalization and the energy of vacancy formation. The degree of delocalization3 is a dimensionless quantity that describes the extent of charge delocalized upon the oxygen sublattice with a vacancy. For x = 0 to 0.375, vacancy formation delocalizes the released electrons onto the lattice as opposed to x = 0.5, where charge from the lattice directly reduces Fe. Covalence between Fe-O bonds is decreased upon the formation of Fe2+, causing a harsh penalty in vacancy formation.In conclusion, tuning MIEC behavior is a balance between reducing Fe and charge delocalization upon the oxide lattice. In terms of electronic conductivity, a small introduction of Pr yielded metallic behavior. In terms of ionic conductivity, a threshold value of Pr yields an unfavorable vacancy formation energy. Future studies will focus on the optimization of the catalytic activity by B-site doping. ACKNOWLEDGMENTS This work has been funded by the Division of Materials Research, a National Science Foundation organization under Award Number 1832809. Computing resources provided by the San Diego Supercomputer Center (SDSC) and Texas Advanced Computing Center (TACC) under XSEDE grant number TG-CTS090100 and USC High-Performance Computing clusters are gratefully acknowledged. REFERENCES T. Hong, M. Zhao, K. Brinkman, F. Chen, C. Xia, ACS Appl. Mater. Interfaces, 9, 8659–8668 (2017)C. Yang, Z. Yang, C. Jin, G. Xiao, F. Chen, Adv. Mater., 11, 1439-1443 (2012)A. M. Ritzmann, J. M. Dieterich, E. A. Carter, Phys. Chem. Chem. Phys., 17, 12260-12269 (2016) Figure 1

Frontiers in hybrid and interfacial materials chemistry research

Abstract

A Comparative Study of Imidazolium-Based Ionic Liquid-Single-Walled Carbon Nanotube Composites with Enhanced Conductivity Properties for Supercapacitor Applications

Mixtures of ionic liquids (ILs) containing single-walled carbon nanotubes (SWCNTs) were prepared and characterized to obtain electrolytes with optimized transport properties for the use in energy storage devices such as supercapacitors. Imidazolium ILs bearing cations with side chains of different functionality coupled with bis(trifluoromethylsulfonyl)amide (NTf2 -) or bis(fluorosulfonyl)amide (FSA-) anions were used in mixtures containing up to 5 wt % SWCNTs. It was determined that the ionic conductivities of all ILs studied can be significantly increased with the addition of single-walled carbon nanotubes when the loading of the nanotubes is above 2 wt %. Moreover, higher conductivities were observed for the ILs containing the NTf2 - anion and 5 wt % SWCNTs. These results can significantly contribute to the development of improved energy storage devices. The work at Brookhaven National Laboratory was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences under contract DE-SC0012704. The work at Brooklyn College was supported by the National Science Foundation, Solid State and Materials Chemistry Program, Division of Materials Research, EAGER award #1841398.

Densified Metallic MoS2/Graphene Enabling Fast Potassium‐Ion Storage with Superior Gravimetric and Volumetric Capacities

Adv. Funct. Mater. 2020, 30, 2001484 In the initially published version of this article, the name of David Mitlin was omitted from the final authors list. The correct author list is as follows: Kai Yao, Zhanwei Xu,* Meng Ma, David Mitlin,* Jiayin Li, Fanyu Lu, and Jianfeng Huang* The respective updated author affiliations are as follows: K. Yao, Dr. Z. Xu, M. Ma, Dr. J. Li, F. Lu, Prof. J. Huang School of Material Science and EngineeringShaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic MaterialsShaanxi University of Science and TechnologyXi'an 710021, China E-mail: xuzhanwei@sust.edu.cn; huangjf@sust.edu.cn Prof. D. Mitlin Materials Science Program and Texas Materials Institute The University of Texas at Austin Austin, TX 78712-1591, USA E-mail: David.Mitlin@austin.utexas.edu The updated Acknowledgements are as follows: This work was supported by the Shaanxi Natural Science Foundation of China No. 2019JLM-3 and 2017JM5006, the State Provincial Key Academic Leaders Scientific Research Foundation of Shaanxi University of Science and Technology No. BJ15-01, the Key Laboratory of Solidification Processing in NWPU No. SKLSP201617, the Xi'an Key Laboratory of green manufacture of ceramic materials Foundation No. 2019220214SYS017CG039, and the National Science Foundation, Division of Materials Research, Award Number 1938833. The authors apologize for any inconvenience this error may have caused.

(Invited) Gas-Phase Clusterfullerene Doping and Exohedral Modification By Laser-Based Methods

We have observed new mechanistic insight into the formation of metallic nitride clusterfullerenes from doped graphite by use of laser-based plasma synthesis techniques, analyzed by ultrahigh resolution 9.4 tesla Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry. These online chemical sampling techniques provide a route to investigate underexplored nanocarbon reactions that take place under the harsh conditions of metallofullerene synthesis, and are expected to be applicable to macroscopic production methods. Here, we report efforts to form various clusterfullerenes by laser vaporization and extend these techniques as new avenues for investigation of exohedral functionalization (e.g., fluorination of Sc3N@C80) and heteroatom-doping of endohedral fullerenes. This work was supported by NSF Division of Materials Research through DMR-11-57490 and the State of Florida.

2nd Materials Research Society of Indonesia Meeting (MRS-Id 2016)

PrefaceThe Materials Research Society of Indonesia (MRS-Id) Meeting is a bi-annual society meeting of the MRS-Id or Himpunan Riset Material Indonesia (HRMI). The 2nd MRS-Id Meeting was held in Bandung from 24th to 26th October 2016 while the first one was in Bali in 2014. It was co-organized by Physics of Electronic Materials Research Division, Faculty of Mathematics and Natural Sciences of Institut Teknologi Bandung (ITB).The aim of this event was to deliver the focus of MRS Indonesia that is to promote materials related with science and technology in Indonesia, regional, and global. We were very pleased that this event could bring together scientists, researchers, and engineers in Indonesia, regional, and global to share their newest scientific works and discoveries in the field of materials science and engineering.Approximately 160 participants have attended the meeting. Among the participants, there were 6 plenary speakers, 26 invited speakers, and 121 contributed speakers. Based on the country where the participants came from, they were from 10 (ten) countries namely France, Germany, Indonesia, Japan, Malaysia, Saudi Arabia, Singapore, Sweden, UK, and USA. This MRS-Id Meeting consisted of 10 (ten) symposia that cover the broad spectra of materials science and engineering.The speakers of the meeting have submitted their full papers for possible publications in a proceeding of IOP Publishing (IOP Conference Series: Materials Science and Engineering) or a journal of IOP Publishing (Materials Research Express). After peer reviewed by experts in related fields, finally, this proceeding contains 36 accepted papers. In addition, there are 20 papers published in the journal after an additional peer-review process of the journal.The Materials Research Society of Indonesia (MRS-Id) acknowledges the enthusiasm of the participants and numerous sponsors, all members of the committees, the international advisory board, Faculty of Mathematics and Natural Sciences of ITB, and all those who have contributed to the success of the 2nd MRS-Id Meeting.The next MRS-Id Meeting will be held in 2018. We are looking forward to welcoming you to the 3rd MRS-Id Meeting!Prof. Khairurrijal KhairurrijalChairman of MRS-Id Meeting 2016 / Current President of MRS-IdDr. Ferry IskandarCo-Chairman of MRS-Id Meeting 2016Prof. Khairurrijal Khairurrijal (ITB, Indonesia), Prof. Kikuo Okuyama (Hiroshima University, Japan), Dr. Ferry Iskandar (ITB, Indonesia), and Dr. Satria Zulkarnaen Bisri (RIKEN, Japan)Editorial Board

Periodically sequenced peptides: A new tool for nanoscale materials synthesis

Event Abstract Back to Event Periodically sequenced peptides: A new tool for nanoscale materials synthesis Matthew Kubilius1 and Raymond S. Tu1 1 City College of New York, Chemical Engineering, United States Synthesizing useful, periodically-sequenced, self-assembling, amphipathic polypeptides is difficult due to increasing polydispersity indices of large molecular weight polymer systems. Accounting for this, we engineered amino acid dimers that polymerize into amphipathic chains with alternating hydrophilic/hydrophobic side groups. This system's periodicity is typical of amino acid sequences that self-assemble into beta-sheets. We limit polydispersity in the growing polypeptide chains through changes to the kinetics of growth by transport-limited chain elongation and partitioning of large molecular weight polypeptides to interfaces. We show that in the absence of a bulk micellular interface, standard condensation polymerization occurs. However, the amphipathic character of our peptide chains increases with increasing molecular weight, resulting in a polypeptide that preferentially partitions into surfactant micelles with increasing molecular weight. Grown that way, with exposure to large, diffuse, bulk-phase interfacial areas, this kinetically-limited growth narrows the polydispersity of our polypeptides. We quantify polydispersity indices using multi-angle light scattering and characterize evolving sheet-like secondary structure using circular dichroism for various amino acid dimer systems. Our results show that the peptides grown in micelle-containing media show significantly enhanced self-assembly and narrowed polydispersity indices. We further characterize these self-assemblies as Langmuir-Blodgett films when the polypeptide partitions strongly to an air-water interface, and image them using Brewster angle microscopy. We conclude that transport-limited polymerization shows great promise in the synthesis of low-cost, surface-active, self-assembling polypeptides. National Science Foundation, Division of Materials Research; National Science Foundation, Chemical, Bioengineering, Environmental, and Transport Systems Keywords: self-assembly, amphiphile, Polymeric material, Polypeptide Conference: 10th World Biomaterials Congress, Montréal, Canada, 17 May - 22 May, 2016. Presentation Type: Poster Topic: Naturally-derived materials and biopolymers Citation: Kubilius M and Tu RS (2016). Periodically sequenced peptides: A new tool for nanoscale materials synthesis. Front. Bioeng. Biotechnol. Conference Abstract: 10th World Biomaterials Congress. doi: 10.3389/conf.FBIOE.2016.01.02762 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 27 Mar 2016; Published Online: 30 Mar 2016. Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Matthew Kubilius Raymond S Tu Google Matthew Kubilius Raymond S Tu Google Scholar Matthew Kubilius Raymond S Tu PubMed Matthew Kubilius Raymond S Tu Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Nanostructured, Bimetallic, Noble Metal Powders Prepared By Atomic Layer Electroless Deposition for Applications in Sensing and Catalysis

Bimetallic materials exhibit properties that are superior to their constituents in many applications. Examples include alkyne hydrogenation catalysts (selectivity), fuel cell cathodes (higher activity), formic acid oxidation catalysts (resistance to poisoning) and hydrogen storage materials (faster kinetics). A key to improving our understanding of these phenomena is preparation of these materials with nanoscale control of composition. Although recent efforts have focused on controlled synthesis of bimetallic particles, there remains a strong need for a synthetic strategy combining the properties of (i) scalability on high-surface-area substrates, (ii) uniform deposition and (iii) low-temperature processing conditions that preserve nanostructures. Presented herein are details of an Atomic Layer Electroless Deposition (ALED) technique that meets these criteria. By exposing Pd powder to dilute hydrogen in nitrogen gas, sacrificial surface PdH is formed along with dilute interstitial hydride. Once the flow of reagent is terminated, addition of metal salts facilitates galvanic displacement of the hydride, and controlled deposition of an overlayer having sub-nanometer thickness. This process can be cycled to create mesoscale layers. The electroless nature of ALED and its ambient processing conditions, make it an excellent complement to existing strategies of noble metal ALD. We will present high-resolution scanning electron microscopy demonstrating that conformal layers can be formed, and that the degree to which three-dimensional growth occurs is dependent upon deposition conditions. In addition, depth-profiles of bimetallic powders of varying adlayer thickness, generated using energy-resolved X-ray photoelectron spectroscopy, will be presented. We will also show evidence for fractional adlayer coverage based on the infrared spectra of adsorbed organic molecules. These data provide a proof of concept for using materials prepared by ALED as high-selectivity, high-dynamic-range sensors for various target molecules. Finally, we will demonstrate the ability of materials prepared in this manner to act as bi-functional catalysts. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000. The Advanced Light Source is supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. Support for JLS was in part provided by the National Science Foundation, Division of Materials Research, grant #1006747. The authors also thank Mark Homer for STEM sample preparation. Figure 1

Effect of Dispersant on Molecular Composition and Fate of Oil Exposed to Sunlight in Seawater Systems

Oil spilled in aquatic systems is exposed to sunlight, resulting in important photochemical processes. Photochemistry likely plays a major role in the fate of oil spilled in areas with sunlight exposure, especially since high molecular weight aromatics are readily photodegraded but are resistant to biodegradation. In order to gain a clearer understanding of the water soluble compounds that are produced as a result of photoegradation, a study was performed to identifiy the water soluble compounds produced from sunlight irradiated oil films. Macondo Well oil was used in this study. A dark and irradiated sample were compared. The irradiated water fraction showed a large amount of oxygenated compounds produced. We utilized FT-ICR MS to identify water soluble compounds from irradiated oil on water. These results will enhance understanding of what type of water soluble compounds are formed in the water as a result of photodegradation and photooxidation. Work performed at the National High Magnetic Field Laboratory was supported by NSF Division of Materials Research through DMR-11-57490, BP/The Gulf of Mexico Research Initiative to the Deep-C Consortium, and the State of Florida. Work performed at the University of New Orleans was supported by the U.S. National Science Foundation (CHE-1111525) and BP/The Gulf of Mexico Research Initiative.

Abstract A57: Distinctive phosphoprotein profiles in a benign breast tissue, and triple-negative primary and metastatic breast cancer tissues from the same African American woman by LC-LTQ/FT-ICR mass spectrometry

Abstract African-American women have a higher risk for developing triple-negative breast cancer (TNBC). Lacking the expression of receptors for estrogen and progesterone, and without human epidermal growth factor 2 receptor gene amplification, TNBC is a very aggressive type of breast cancer with a high likelihood of metastasis and recurrence. Specific therapeutic targets for this aggressive disease remain to be identified. Phosphorylation, a post-translational modification that adds one or more phosphate groups to a protein, plays a key role in the activation and deactivation of a protein's cellular function. Here we report the first systematic phosphoproteomic analysis of a benign breast tissue, a primary breast cancer tissue, and a metastatic breast cancer tissue from the same African-American woman. Differential phosphoprotein levels were measured with a reversed-phase nano-liquid chromatograph coupled to a hybrid linear quadrupole ion trap/Fourier transform ion cyclotron resonance mass spectrometer (LC-LTQ/FT-ICR MS). Five proteins are found to be highly phosphorylated in the metastasis site of a triple negative breast cancer patient, e.g. hepatoma-derived growth factor and Isoform HMG-Y of high mobility group protein HMG-I/HMG-Y. Six proteins are found to be highly phosphorylated in the primary cancer site of a triple negative breast cancer patient, e.g. isoform 2 of transcription intermediary factor 1-beta and isoform 1 of clathrin heavy chain 1. Identified phosphoproteins are known to be involved in breast cancer signal transduction pathways. For example, the decrease in sumoylation by doxorubicin of isoform 2 of transcription intermediary factor 1-beta (TRIM28) protein was reported to be essential to induce p21 expression, and thus cell growth inhibition in MCF-7 breast cancer cells. In patients with invasive breast cancers, the co-expression of heat-shock protein (HSP) 90 alpha with an overexpressed kinase, or along with the loss of a phosphatase and tensin homologue deletion on chromosome 10, is a putative molecular prognostic marker to predict early relapse. Moreover, HSP90-alpha, which is expressed extracellularly from breast cancer cells, interacts with matrix metalloproteinase-2 (MMP2). This interaction promotes MMP2 activation, which is crucial for tumor invasiveness. HSP90-alpha is also involved in several signal pathways related to breast cancer. These results may identify new diagnostic biomarkers and therapeutic targets for TNBC. (This work was supported by grant BCTR0504465 from the Susan G. Komen for the Cure Breast Cancer Foundation, grants from the Florida Breast Cancer Coalition Research Foundation, and the Florida State University to Prof. Q.-X. Sang and by NSF Division of Materials Research through DMR-0654118 and the State of Florida to Prof. Alan G. Marshall. We also acknowledge the Cooperative Human Tissue Network Southern Division, University of Alabama at Birmingham, from which we obtained the tissues for this project.) Citation Information: Cancer Epidemiol Biomarkers Prev 2011;20(10 Suppl):A57.

APPOINTMENT Engineering professor is next head of NSF’s Materials Research Division

Ian M. Robertson, an engineering professor at the University of Illinois, Urbana-Champaign (UIUC), will be the next director of the Division of Materials Research at the National Science Foundation. Robertson, whose appointment takes effect on Jan. 3, 2011, will replace Zakya H. Kafafi, who will finish her three-year term later this year. The division has a 2010 budget of just over $300 million and operates under NSF’s Directorate for Mathematical & Physical Sciences. “This appointment recognizes Ian’s leadership, significant research, and educational contributions to the field,” Ilesanmi Adesida, dean of the College of Engineering at UIUC, said in a statement. The college’s department of materials science and engineering, which Robertson headed from 2003 to 2009, “has been the top-ranked materials science program in the nation for many years and Ian has been a key participant in achieving that distinction,” Adesida said. Robertson, 53, received a doctorate in metallurgy from the University of Oxford in ...

Calcium-Induced Conformational Changes in the Cardiac Isoform of the Troponin Complex Monitored By Hydrogen/deuterium Exchange and Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

Calcium-induced conformational changes in the cardiac troponin complex have been determined from solvent accessibility data measured by solution-phase hydrogen/deuterium exchange (HDX). The troponin complex was digested with protease XIII and the peptides identified by FT-ICR mass spectrometry. To uniquely assign proteolytic fragments of the same mass, experiments were performed with troponin subunits isotopically depleted in 13C and 15N. For instance, the peptide with monoisotopic m/z = 592.983+could be either TnT fragment 76-91 or to TnI fragment 155-170, also known as the switch peptide. Isotopic depletion uniquely identified the TnT fragment.Comparison of the HDX rates in the isolated subunits and those observed in the reconstituted complex identified inter-subunit interfaces, in general agreement with the x-ray structure of the core complex (Takeda et al. Nature, 2003 424 (6944)). HDX experiments for the complex in the presence and in the absence of calcium revealed a multitude of conformational changes, some of which were not apparent from comparison of Ca-saturated and Ca-free x-ray structures of skeletal troponin (Vinogradova et al. PNAS, 2005 102 (14)). For example, the C-lobe of TnC, which was not expected to change upon Ca binding, showed different HDX rates in the presence and in the absence of Ca for peptides 105-119 and 150-153. Similar effects were observed for residues 24-27 of TnC, but smaller differences were found for the TnI switch peptide (158-162), the N-terminus of TnI, and the IT coiled-coil. These observed changes will be discussed in the context of the cardiac and skeletal crystal structures. This work was supported by NIH (R01 GM78359), NSF Division of Materials Research through DMR-06-54118, and the State of Florida.

Ceramic collaborations around the world

International collaboration can be an integral part of a research project. It can add scientific expertise or interdisciplinarity, enhance equipment and facilities; and strengthen the training and education of students. In recognition of these benefits, the National Science Foundation (NSF) of the United States has supported researchers in many different modes. One option for ceramists is the Materials World Network (MWN) program. Today, approximately 24% of the active projects in the Ceramics Program (CER) of NSF’s Division of Materials Research (DMR) are funded through the MWN program (or its precursors). Each project includes participants from two or more countries and collectively they include researchers from 16 countries. This year an additional 33 ceramic proposals, including renewals, were merit-reviewed in panels and seven awards were made. Characteristics of the best proposals include synergistic pairings of interests and expertise between international partners, detailed plans for student exchanges, activities to broaden the participation of groups under-represented in science, and cutting-edge creative and original research ideas. As well, NSF supports many international activities through the Office of International Science and Engineering (OISE) including regional opportunities. Instrumentation and facilities supported by NSF, particularly those in Materials Science and Engineering, are often accessible on an international basis.

The Humacao Strange Matter Exhibition: Prem Brings Materials Science and Nanotechnology to Puerto Rican Communities

AbstractThe “UPRH-PENN Partnership for Research and Education in Materials” (PREM) is sponsored by the Division of Materials Research of the National Science Foundation and since 2004 it has contributed to increasing the participation of Puerto Rican men and women in materials research and education. The program integrates K-12, undergraduates, graduate students, and faculty collaborating through research and education in a partnership between the University of Puerto Rico at Humacao (UPRH) along with UPRC and UPRRP and the University of Pennsylvania Materials Research Science & Engineering Center. The UPRH-PREM has strong links with schools in the eastern region of Puerto Rico and has successfully integrated K-12 students and teachers into the program through workshops, web resources, open houses, a Summer Program and research experiences during the academic year. In an effort to integrate the wider community into the outreach efforts, from October to December 2007 PREM hosted the presentation of the Interactive Materials Science Exhibition “Strange Matter”. “Strange Matter” was designed and produced by the Materials Research Society (MRS) in conjunction with the Ontario Science Centre in Toronto. Funding for the project is being provided by the National Science Foundation and industrial partners 3M, Dow, Ford, Intel, and Alcan. The exhibition brings interactive activities that highlight the fact that materials science is all around us. This exhibition is the first and only one in the island of Puerto Rico and was presented at UPRH's Casa Roig Museum, a historic plantation house located in downtown Humacao. Local scientists complemented the exhibition with live demonstrations and talks to provide deeper explanations and motivate young visitors to study materials. To make the exhibition possible, PREM integrated UPR-Humacao administration, faculty, students, non-teaching workers, Casa Roig staff, schools, Humacao municipality, local businesses and individual citizens. Dozens of students, faculty and other members of the community were mobilized as volunteers to support all aspects of the exhibition.

Block copolymers and nanotechnology

Recent years have witnessed a large number of fundamental studies aimed at understanding the structure–property relationships of polymers with nanoscale features. Support for this work is largely based on the potential applications of polymers in nanotechnology. Emerging applications have demonstrated the utility of block copolymers in the creation of functional nanostructures. Building on the pioneering work of Russell et al.,1 Register et al.,2 and Kramer et al.,3 the IBM group4 has created nanostructured thin films for flash-memory applications. A patterned block copolymer film is deposited on a silica substrate, and the pattern is transferred into the substrate by reactive ion etching. The resulting ceramic layer contains 20-nm-diameter holes in which doped silicon crystals are subsequently grown. The presence of this composite thin film between the control and floating gates improves the robustness of flash-memory devices. This development, which may signal a profound shift in computer data storage away from disk drives, does not require registry between the nanoscale features (the holes in which the crystals were grown). If registry between features can be enforced, then ultrahigh-density magnetic storage devices may be created with this approach.5 Although the advances described in the preceding paragraph are impressive, it is our view that we are at the very early stages of our search for applications based on polymer nanoscience. Like all disciplines in their infancy, our understanding of the factors that control the structure and functionality of nanostructured polymers is limited. Thus, the number of fundamental studies that can be undertaken at this point is virtually limitless. A simple example is the morphology of ABC triblock copolymers. From the pioneering experimental work of Stadler et al.,6 it is clear that a wide variety of morphologies can be obtained with these systems. It is likely that the number of phases that will ultimately be found if these systems are fully explored (including different values and signs of the Flory–Huggins interaction parameter, molecular weights of the blocks, and statistical segment lengths) will exceed 10,000. Does it make sense to embark on a study to enumerate all of these phases? Although the answer to this question is obvious, deciding which ABC triblock copolymers to study is not. Similar questions can be raised about other branches of polymer nanoscience, such as nanoparticle/polymer mixtures, polymer thin films, and multicomponent polymer blends. To answer such questions, it is instructive to examine the paths adopted by some of the highly successful fields based on physical sciences in the 20th century. One example of such a field is conventional polymer science. In this case, compelling technological applications such as vulcanized rubber were in the market many decades before the concept of chain molecules took root.7 Similarly, in the case of solid-state physics, devices such as the transistor radio and telephones were available to the public despite a limited understanding of semiconductor physics. It is our view that the fundamental challenge facing polymer nanoscience is the identification of truly compelling applications. Although making more effective computers with the help of block copolymers is certainly a very important beginning, it will probably not change the world in the manner that polyethylene and silicon did. Big problems such as incurable diseases, harnessing energy not based on fossil fuels, and alternate sources8 for carbon-based synthetic materials (the fact that the world is addicted to petroleum-based synthetic materials that are not recycled seems to be lost in the energy debate) are easy to spot, but identifying the connection between polymer nanoscience and the solutions to these problems is not. An important goal for the near future must be to identify such connections and demonstrate solutions, despite our limited fundamental understanding of polymer nanoscience. Just as solid-state physicists had no difficulty deciding on the composition of the crystals on which they would focus their attention, it will then be straightforward for polymer nanoscientists to identify important directions of research and convince society to support these directions. The authors gratefully acknowledge the National Science Foundation for its financial support [through the Division of Materials Research (grant 0514422) and the Division of Chemical and Transport Systems (grant 0305711)] and the U.S. Department of Energy [through the Office of FreedomCAR and Vehicle Technologies and the Office of Basic Energy Sciences] for its support of their research efforts in the area of block copolymer nanostructures.

Influence of diatom exopolymers and biofilms on metamorphosis in the barnacle Balanus amphitrite

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 301:231-245 (2005) - doi:10.3354/meps301231 Influence of diatom exopolymers and biofilms onmetamorphosis in the barnacle Balanus amphitrite Jagadish S. Patil, Arga Chandrashekar Anil* Marine Corrosion and Materials Research Division, National Institute of Oceanography, Dona Paula, Goa 403 004, India *Email: acanil@darya.nio.org ABSTRACT: Natural biofilms constitute a complex network of microorganisms (bacteria, diatoms, protozoa, fungi) and their extracellular polymeric substances (EPS), which influence settlement in benthic invertebrates. We investigated the influence of diatom (Bacillariophyceae) films and EPS (>1000 molecular weight) on metamorphosis in the acorn barnacle Balanus amphitrite Darwin, a dominant fouling organism, using axenic and non-axenic films, and free and biofilm EPS, of 5 species of pennate diatoms: Amphora coffeaeformis and A. rostrata, and Navicula transitans var. derasa f. delicatula, N. crucicula and N. subinflata. Fourier-transformed infrared spectroscopy (FTIR) spectra revealed that the EPS produced by diatoms are of similar nature; however, the proportion of monosaccharides varies with species, indicating a potential role for influencing larval metamorphosis. Free EPS of axenic diatoms had no effect, whereas biofilm EPS induced larvae to metamorphose. Amphora spp. produced more biofilm EPS, but had relatively weaker effects than Navicula spp. Axenic diatom films also facilitated larval metamorphosis (depending on species and cell density) in some cases, suggesting that the cues provided by the diatoms themselves can also mediate invertebrate larval metamorphosis in the absence of microbial films. Non-axenic diatom films (which had higher cell densities) and biofilm EPS promoted metamorphosis to a greater degree than those of axenic diatoms. Enhancement of metamorphosis depended on diatom species and on their density in the films, as well as on the composition of their EPS. Differential responses of barnacle larvae to different diatom species and their EPS indicate that each diatom species provides a different set of physico-chemical signals to settling larvae. KEY WORDS: Diatoms · Bacillariophyceae · Extracellular polymeric substances · Biofilms · Larvae · Balanus amphitrite Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 301. Online publication date: October 11, 2005 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2005 Inter-Research.

Elevated Temperature Mechanical Properties of Devitrified Metallic Glass

AbstractElevated temperature tensile tests of different microstructures arising from different heat treatments of the Fe-based metallic glass Vitroperm (Fe73.5Cu1Nb3Si15.5B7) are presented. An anneal at 600°C for 1h yields a single phase μ-Fe microstructure with equiaxed, randomly oriented 15 nm grains, which is an ideal candidate for study of material properties at diminishing length scale. This microstructure has good stability during tensile testing at 600°C, showing a strain rate exponent correlating to grain boundary sliding (m=0.5), but little ductility, and strengths to 1250 MPa. The brittle behavior could be attributed to the lack of dislocation activity at such length scales. At temperatures up to 725°C, grain growth occurs, leading to elongations as large as 65% at flow stresses of 250 MPa. Precipitation of a second Nb-rich phase accompanies the grain growth. This investigation is supported by NSF, Division of Materials Research, grant NSF-DMR-0240144.