Adhesion-based separation is generally preferred when cell subpopulations of interest are of the same size and density as other cells in a heterogeneous suspension. However, when size differences exist, alternative separation strategies can be pursued. Size-based separation offers the advantage of not requiring a priori knowledge of cell surface markers and minimizing any cellular-level changes due to cell-ligand interactions. This presentation will describe two examples of size-based separation, namely red blood cell depletion from whole human blood and cardiac muscle cell enrichment for tissue engineering.
Shashi Murthy , Professor of Chemical Engineering, Northeastern University.
224 Bldg, Rm. A312. (NIST Contact: Dean DeLongchamp, 301-975-5599, deand@nist.gov)

11:00 AM - BIOCHEMICAL SCIENCE DIVISION SEMINAR: The Roles of Mechanical Damage and Remodeling in Intervertebral Disc Degeneration
James Iatridis , Associate Professor, School of Engineering, University of Vermont.
227 Bldg, Rm. A202. (NIST Contact: Robert Goldberg, 301-975-2584, robert.goldberg@nist.gov)

2:00 PM - ELECTRON AND OPTICAL PHYSICS DIVISION SEMINAR: Matrices of single-photon avalanche diodes for biomolecular analysis
In this talk I will describe my work at Politecnico di Milano related to the design of analysis systems for DNA and proteins, based on single photon avalanche photodiodes (SPADs). These devices are easy to integrate and miniaturize, so are suitable for for low cost portable biological equipment. I first report a demonstration of the use of SPADs in microchip electrophoresis with single and multi-wavelength laser induced fluorescence. The development of monolithic matrices or arrays of SPADs enables parallel single photon counting on different channels leading to higher throughput and the possibility of multi-wavelength photon counting. Looking at these possibilities I designed a 6x8 matrix of SPADs intended for parallel chemiluminescence and I built a complete and compact optical and mechanical system for automated analisys of protein microarrays. The integration of SPADs on the same silicon chip leads to issues regarding the electrical and optical crosstalk between the devices. I discuss how it is possible to completely eliminate the first effect, and I show measurements of the optical crosstalk using coincidence counting techniques. Today, state of the art equipment for DNA and protein analysis is based on charge-coupled device cameras or confocal scanning microscopes with photomultipliertubes. Both such systems work in analogue mode, i.e. the detector output is an electrical quantity proportional to the photon emission rate. This provides sensitivity down to single molecule levels, but single-photon counting techniques can often provide better sensitivity and provide for advanced measurement techniques such as sinusoidal lock-in in the shot-noise limited regime, and fluorescence correlation Spectroscopy. As a demonstration of advanced single photon counting techniques I designed and tested a novel full-digital sinusoidal lock-in amplifier designed to operate with single photon events. Experimental results show that it is essentially limited by shot noise and can work with extremely low photon count rates.
Alessandro Restelli , Research Associate, Electron and Optical Physics Division.
Radiation Physics Bldg, Rm. B105. (NIST Contact: Charles Clark, 301-975-3709, charles.clark@nist.gov)
Special Assistance Available

3:00 PM - POLYMERS DIVISION SEMINAR : Surface Wrinkling as a Metrology Tool
Surface wrinkling has proven to be a widely exciting area of intrigue and opportunity. It has provided a fertile research area for studying spontaneous surface patterning, the fabrication of devices and structures that take advantage of these wrinkled surfaces, and the underlying mechanics governing surface wrinkling under various conditions and in different geometries. We have added a new twist to this already diverse field: to use surface wrinkling as a metrology tool to harvest information on the mechanical properties of polymer thin films. This presentation will highlight new directions we are pursuing that will greatly expand the measurement capabilities of this wrinkling technique.
Christopher Stafford , NIST.
224 Bldg, Rm. A312CR. (NIST Contact: Jack Douglas, 301-975-6779, jack.douglas@nist.gov)


3/14 -- WEDNESDAY

9:00 AM - TECHNOLOGY SERVICES SEMINAR: NVLAP Assessor Seminar
The National Voluntary Laboratory Accreditation Program (NVLAP) accredits testing and calibration laboratories that are found competent to perform specific tests and calibrations. NIST Handbook 150, Procedures and General Requirements, and ISO/IEC 17025, General Requirements for the competence of testing and calibration laboratories, will be presented to current NVLAP assessors, new assessors and others that are interested in laboratory accreditation. Seminar size is limited to 20. Anyone interested in attending should contact Betty Ann Sandoval as soon as possible.
. . , ..
Metrology Building, Room B341. (NIST Contact: Betty Sandoval, 301-975-8446, betty.sandoval@nist.gov)

10:30 AM - CERAMICS DIVISION SEMINAR: Ferroelasticity and Crack Tip Domain Switching in PZT
PZT was used in the manufacturing of about 16 million piezoceramic fuel injector systems in 2006 Germany alone and for at least 600 000 miniature piezomotors. A few examples for applications will motivate the following scientific discussion. Soft PZT exhibits marked ferroelasticity which leads to crack tip shielding in mechanically driven cracks, anti-shielding in electrically driven cracks and strain incompatibility between electrically active and inactive regimes with attendant crack initiation and crack propagation. After the introduction on applications, the talk is divided in five parts: 1) A brief description of the basic material properties, explanation of the relevant phenomena, some equations. 2) Description of ferroelasticity exemplified by the stress-strain curve, utilization of ferroelasticity to highlight a newly developed technique of electromechanical poling. 3) Measurements of R-curve behavior with salient influences provided by poling state, sample thickness, electrical boundary conditions. 4) Elaboration of crack propagation due to electrical cycling without a mechanical load. 5) Effects of strain incompatibility at electrode edges on crack initiation and crack propagation.
Jurgen Rodel , Technical University Darmstadt.
Materials Building, Rm. A250. (NIST Contact: Sheldon Wiederhorn, 301-975-5772, sheldon.wiederhorn@nist.gov)

1:00 PM - POLYMERS DIVISION SEMINAR: Electrochemical Nanopatterning and Nanocharging using Precursor Polymers and Nanostructured Ultrathin Films
The investigation of nanopatterning strategies using surface probe microscopy (SPM) techniques is of high interest due to the number of probes and techniques that have been developed through the years including dip pen nanolithography (DPN) and electrochemical nanolithography. The chemical reactions or physical adsorption in SPM methods can involve the delivery of the functional molecule via the cantilever tip as in DPN or the chemicals are simply coated or pre-assembled on the substrate. In this talk, we will give several strategies and materials systems involving electrochemical and electrostatic nanolithography of precursor polymers and electro-active polymers resulting in high resolution patterns. This utilizes conducting AFM (current sensing AFM) on both Au and Si conducting substrates. Electrochemical conversion to more conjugated derivatives and/or by joule heating results in patterns that can be controlled by bias voltage, writing speed, film thickness, and composition. The use of other semi-conducting materials resulted in nanocharging (for memory devices) or cis-trans thermal back isomerization resulting in induced nano mass transport (nanostructured surface relieve gratings). The possibility for complex patterning and parallel processing is limited by both the instrumentation and material stability.
Rigoberto Advincula , Associate Professor.
224 Bldg, Rm. A312. (NIST Contact: Derek Patton, 301-975-3586, derek.patton@nist.gov)


3/15 -- THURSDAY

10:30 AM - EPG SEMINAR SERIES: Materials Design in the Nanometer Range at EMPA in Switzerland
EMPA, a Materials Science and Technology Institution in the domain of the Swiss Federal Institute of Technology (ETH), runs an application oriented nanotechnology program. I will present highlights of our work in the following areas: carbon nanotube field emitters, hydrogen defects in graphitic nanostructures, nanostructured hard coatings for reduced wear and friction, the synthesis, properties and use of nanoparticles, nanoparticulate functionalized fibers, nanosized particles in emissions from combustion processes, risk analysis, and the 3D-analysis of cementous nanopores using FIB techniques. EMPA welcomes collaborations and invites guest scientists and engineers.
Louis Schlapbach , CEO of EMPA and Prof. Experimental Physics, ETH, Zurich, Switzerland, Louis.Schlapbach@empa.ch.
217 Bldg, Rm. H107. (NIST Contact: Daniel T. Pierce, 301-975-3711, daniel.pierce@nist.gov)

10:30 AM - POLYMERS DIVISION SEMINAR: Rapid Cell Growth On Biodegradable Polymer Scaffolds
Kytai Nguyen , Assistant Professor, Arlington, TX, knguyen@uta.edu.
224 Bldg, Rm. A312. (NIST Contact: Thuy Chastek, 301-975-4349, thuy.chastek@nist.gov)


3/16 -- FRIDAY

1:00 PM - INTELLIGENT SYSTEMS DIVISION SEMINAR: Annual Research Advisory Committee (RAC) All-Staff Briefing
Did you know that

• NIST has greatly increased the number of professional organizations for which it will pay dues
• More OUs have posted specific promotion criteria on their internal web sites,
• The NIST Library will now provide publications through the ISI web service dating back to 1945 (previously it was only through 1975)?