This research project has received funding from the European Research Council under the European Community's Seventh Framework Programme (FP7/2007-2013) / ERC grant agreement n &deg; 242710 and was additionally supported by the Human Frontier Science Program and the Emmy Noether Program of the German Research Foundation (SCHR 995/2-1).

<ol>
	<li>Schr&#246;der, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Xenon+for+NMR+biosensing+-+Inert+but+alert.">Xenon for NMR biosensing - Inert but alert.</a> Phys Med. , (2011).</li><li>Viale, A., Reineri, F., Santelia, D., Cerutti, E., Ellena, S., Gobetto, R., Aime, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hyperpolarized+agents+for+advanced+MRI+investigations.">Hyperpolarized agents for advanced MRI investigations.</a> Q J Nucl. Med. Mol. Imaging. 53, 604-617 (2009).</li><li>Walker, T. G., Happer, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spin-exchange+optical+pumping+of+noble-gas+nuclei.">Spin-exchange optical pumping of noble-gas nuclei.</a> Rev. Mod. Phys. 69, 629-642 (1997).</li><li>Albert, M. S., Cates, G. D., Driehuys, B., Happer, W., Saam, B., Springer, C. S., Wishnia, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biological+magnetic+resonance+imaging+using+laser-polarized+129Xe.">Biological magnetic resonance imaging using laser-polarized 129Xe.</a> Nature. 370, 199-201 (1994).</li><li>Cherubini, A., Bifone, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hyperpolarised+xenon+in+biology.">Hyperpolarised xenon in biology.</a> Progr. NMR Spectrosc. 42, 1-30 (2003).</li><li>Goodson, B. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nuclear+magnetic+resonance+of+laser-polarized+noble+gases+in+molecules,+materials,+and+organisms.">Nuclear magnetic resonance of laser-polarized noble gases in molecules, materials, and organisms.</a> J. Magn. Reson. 155, 157-216 (2002).</li><li>Nikolaou, P., Whiting, N., Eschmann, N. A., Chaffee, K. E., Goodson, B. M., Barlow, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Generation+of+laser-polarized+xenon+using+fiber-coupled+laser-diode+arrays+narrowed+with+integrated+volume+holographic+gratings.">Generation of laser-polarized xenon using fiber-coupled laser-diode arrays narrowed with integrated volume holographic gratings.</a> J. Magn. Reson. 197, 249-254 (2009).</li><li>Ruppert, K., Brookeman, J. R., Hagspiel, K. D., Mugler, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Probing+lung+physiology+with+xenon+polarization+transfer+contrast+(XTC).">Probing lung physiology with xenon polarization transfer contrast (XTC).</a> Magn. Reson. Med. 44, 349-357 (2000).</li><li>Driehuys, B., Cofer, G. P., Pollaro, J., Mackel, J. B., Hedlund, L. W., Johnson, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Imaging+alveolar-capillary+gas+transfer+using+hyperpolarized+129Xe+MRI.">Imaging alveolar-capillary gas transfer using hyperpolarized 129Xe MRI.</a> Proc. Natl. Acad. Sci. U.S.A. 103, 18278-18283 (2006).</li><li>Spence, M. M., Rubin, S. M., Dimitrov, I. E., Ruiz, E. J., Wemmer, D. E., Pines, A., Yao, S. Q., Tian, F., Schultz, P. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functionalized+xenon+as+a+biosensor.">Functionalized xenon as a biosensor.</a> Proc. Natl. Acad. Sci. U.S.A. 98, 10654-10657 (2001).</li><li>Schr&#246;der, L., Lowery, T. J., Hilty, C., Wemmer, D. E., Pines, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+imaging+using+a+targeted+magnetic+resonance+hyperpolarized+biosensor.">Molecular imaging using a targeted magnetic resonance hyperpolarized biosensor.</a> Science. 314, 446-449 (2006).</li><li>Schrank, G., Ma, Z., Schoeck, A., Saam, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+a+low-pressure+high-capacity+129Xe+flow-through+polarizer.">Characterization of a low-pressure high-capacity 129Xe flow-through polarizer.</a> Phys. Rev. A. 80, 063424 (2009).</li><li>Levron, D., Walter, D. K., Appelt, S., Fitzgerald, R. J., Kahn, D., Korbly, S. E., Sauer, K. E., Happer, W., Earles, T. L., Mawst, L. J., Botez, D., Harvey, M., DiMarco, L., Connolly, J. C., M&#246;ller, H. E., Chen, X. J., Cofer, G. P., Johnson, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Magnetic+resonance+imaging+of+hyperpolarized+129Xe+produced+by+spin+exchange+with+diode-laser+pumped+Cs.">Magnetic resonance imaging of hyperpolarized 129Xe produced by spin exchange with diode-laser pumped Cs.</a> Appl. Phys. Lett. 73, 2666 (1998).</li><li>Zhou, X., Sun, X. P., Luo, J., Zeng, X. Z., Liu, M. L., Zhan, M. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Production+of+Hyperpolarized+129Xe+Gas+Without+Nitrogen+by+Optical+Pumping+at+133Cs+D2+Line+in+Flow+System.">Production of Hyperpolarized 129Xe Gas Without Nitrogen by Optical Pumping at 133Cs D2 Line in Flow System.</a> Chin. Phys. Lett. 21, 1501-1503 (2004).</li><li>Zhou, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hyperpolarized+noble+gases+as+contrast+agents.">Hyperpolarized noble gases as contrast agents.</a> Methods Mol. Biol. 771, 189-204 (2011).</li><li>Seltzer, S. J., Michalak, D. J., Donaldson, M. H., Balabas, M. V., Barber, S. K., Bernasek, S. L., Bouchiat, M. A., Hexemer, A., Hibberd, A. M., Kimball, D. F., Jaye, C., Karaulanov, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Investigation+of+antirelaxation+coatings+for+alkali-metal+vapor+cells+using+surface+science+techniques.">Investigation of antirelaxation coatings for alkali-metal vapor cells using surface science techniques.</a> J. Chem. Phys. 133, 144703 (2010).</li></ol>

No conflicts of interest declared.

Critical aspects in the preparation of hyperpolarized xenon are oxygen impurities in the gas manifold including the pumping cell and sufficient illumination of the cell with circularly polarized light. The above mentioned light bulb test is a simple way to detect deleterious oxygen concentrations while transferring rubidium. The alkali metal might loose its shiny surface by the time the cell is installed in the polarizer. However, sufficient vaporization of non-oxidized Rb can be monitored by reduced laser transmission (...

Hyperpolarized agents are gaining increasing attention for NMR/MRI applications since they can solve the sensitivity problem under certain circumstances 2. Three major approaches are currently used (dynamic nuclear polarization, DNP; para-hydrogen induced polarization, PHIP; and spin exchange optical pumping, SEOP) that all prepare an artificially increased spin population difference outside an NMR magnet prior to the actual spectroscopy or imaging experiment. Here we describe the function and operation of a SEOP setup that has been optimized for production of hyperpolarized129Xe used in solution state experiments.
An essential component is an intense light source emitting infrared photons at 795 nm. Laser diode arrays (LDA) are convenient devices that provide high power output &gt; 100 W at reasonable cost. In many setups, the LDA is emitting into an optical fiber that more or less retains the polarization of the laser light. To guarantee a sufficient SEOP process this elliptical polarization must be converted into circular polarization of high purity. Major components of the polarization optics are shown in Figures 1 and 2 and setting up the system is explained schematically in supplementary movie 1.
To circularly polarize the light we first attach the fiber end to a primary beam expansion optics (e.g., a fiber collimator) for reducing power density. The light then passes through a polarizing beam splitter cube, generating linearly polarized light. By rotating this cube we can determine the preferred axis of the remaining polarization with a power meter. Maximum transmission corresponds to the situation where the fast axis of the cube is aligned with the principal light polarization axis. Cubes with high extinction coefficients (100,000 : 1 or better) yield a good separation of polarization components. This can be tested using a second beam splitter cube as an analyzer that is rotated while the first one is aligned for maximum transmission of the extra-ordinary beam.
Once the linear polarization of the transmitted light has been confirmed, a &lambda;/4 wave plate designed for 795 nm is introduced into the extra-ordinary beam to convert linear into circular polarization. For this purpose, the fast axis of the wave plate is rotated by 45 &deg; relative to the beam splitter cube fast axis. (If desired, circular polarization of the reflected ordinary beam with its linear polarization axis perpendicular to the extra-ordinary beam can be achieved in a similar manner.)
The quality of the circular polarization can be tested with a second beam splitter cube that should yield constant transmission upon rotation. A secondary beam expansion optics (e.g. two lenses in a Galilean telescope configuration) then increases the beam diameter to completely illuminate the glass cell for the pumping process inside an oven box. Absorption of the laser light by Rb vapor in the cell is monitored through a pin hole behind the pumping cell at the end of the box: a collimator collects an attenuated IR beam to be analyzed with an optical spectrometer (see Figure 3 for pumping cell setup).
A heating mechanism outside the pumping cell partially vaporizes a Rb droplet sitting inside the cell (Figure 4a) and therefore causes laser light absorption. Density of the vapor can be adjusted via the heating set point of the respective PID controller. High temperatures (ca. 190 &deg;C) are good for compact setups where the xenon has a limited amount of time to build up polarization. The gas mixture containing Xe, N2 and He flows through the pumping cell opposite to the laser beam direction (Figure 3). An external magnetic field aligned with the laser beam ensures that the IR photons are only pumping one Rb transition. Relaxation of the electron states is fast and must be non-radiative to avoid emission of IR photons with 'wrong' polarization. Here, the N2 comes into play as a quench gas. Eventually, the Rb system builds up an overpopulation of one of the ground state sublevels while the other one is continuously depleted by the laser (Figure 5). Xenon getting in close contact to the Rb atoms experiences spin-spin interactions and the electron spin polarization is transferred onto Xe nuclei in flip-flop processes.
The hyperpolarized gas flowing out of the pumping cell contains trace amounts of Rb vapor that condensate on the tubing wall within a few cm of the outlet due to the low temperature (similar to Figure 4b). In vivo applications, however, would require additional elimination of the alkali metal (e.g. through a cold trap) whereas in vitro experiments can be performed safely with the gas as it leaves the hyperpolarizer. Teflon tubing connects the polarizer outlet with the inlet of a glass apparatus to perform NMR experiments on test solutions. Mass flow controllers are used to adjust the amount of Xe flowing into the NMR setup. They are triggered by commands in the NMR pulse sequence. After checking the achieved polarization enhancement, the gas can be used as an NMR/MRI contrast agent in solution state experiments.
Xe has a certain solubility in water (4.5 mM/atm) and other solvents. It therefore can already serve on its own as a contrast agent to display the distribution of some liquids. However, it is also possible to link the NMR-active nuclei to certain molecules in order to acquire molecular-specific information through the otherwise inert gas. By providing a molecular host for the dissolved Xe, it is possible to confer molecular specificity to the Xe NMR signal. This provides the opportunity to design functionalized contrast agents - also called biosensors - when such a host structure is coupled to a targeting unit that binds to specific analytes of biomedical interest (Figure 6).
Further sensitivity enhancement is required when the biosensor should be detected at concentrations that are low for MR contrast agents (&lt; 100 &mu;M). This can be achieved by chemical exchange saturation transfer (CEST). This method detects the biosensor indirectly by destroying the magnetization of the caged Xe and observing the signal change of free Xe in solution. Since the hyperpolarized nuclei are continuously replaced after some 10 ms, many 100 to 1000 nuclei transfer the information onto the detected pool and amplify the signal ca. 103-fold (see movie 2).

<table border="1">
<tbody>
 <tr>
 <td>Name of the reagent</td>
 <td>Company</td>
 <td>Catalogue number</td>
 <td>Comments (optional)</td>
 </tr>
 <tr>
 <td>Rb ingot</td>
 <td>Sigma-Aldrich</td>
 <td>276332-1G</td>
 <td></td>
 </tr>
 <tr>
 <td>P4O10</td>
 <td>Sigma-Aldrich</td>
 <td>79610-500G</td>
 <td></td>
 </tr>
 <tr>
 <td>Ar</td>
 <td>Praxair</td>
 <td></td>
 <td></td>
 </tr>
 <tr>
 <td>Xe</td>
 <td>Sigma-Aldrich</td>
 <td>00472-1EA</td>
 <td></td>
 </tr>
 <tr>
 <td>O2</td>
 <td>Sigma-Aldrich</td>
 <td>00476-1EA</td>
 <td></td>
 </tr>
 <tr>
 <td>Laser system</td>
 <td>QPC Lasers/Laser Operations</td>
 <td>Brightlock 50</td>
 <td></td>
 </tr>
 <tr>
 <td>Vacuum system</td>
 <td>Pfeiffer</td>
 <td>HiCube</td>
 <td></td>
 </tr>
 <tr>
 <td>Thermocouples</td>
 <td>Newport Omega</td>
 <td>SA2F-KI-3M</td>
 <td></td>
 </tr>
 <tr>
 <td>Silicon heater</td>
 <td>Newport Omega</td>
 <td>FMA5514</td>
 <td></td>
 </tr>
 <tr>
 <td>Pressure transducer</td>
 <td>Newport Omega</td>
 <td>PR 33X-V-10</td>
 <td></td>
 </tr>
 <tr>
 <td>Process meter</td>
 <td>Newport Omega</td>
 <td>INFCP-100B</td>
 <td></td>
 </tr>
 <tr>
 <td>Mass flow controllers</td>
 <td>Newport Omega</td>
 <td>MFC</td>
 <td></td>
 </tr>
 <tr>
 <td>PID regulators</td>
 <td>Newport Omega</td>
 <td>CN7800</td>
 <td></td>
 </tr>
 <tr>
 <td>Control Software</td>
 <td>Newport Omega</td>
 <td>DasyLab</td>
 <td></td>
 </tr>
 <tr>
 <td>Data acquisition</td>
 <td>Newport Omega</td>
 <td>Daqboard 3000</td>
 <td></td>
 </tr>
 <tr>
 <td>Vacuum sensor</td>
 <td>Oerlikon</td>
 <td>TTR91</td>
 <td></td>
 </tr>
 <tr>
 <td>Vacuum controller</td>
 <td>Vacom</td>
 <td>MVC-3</td>
 <td></td>
 </tr>
 <tr>
 <td>Beam collimator</td>
 <td>Thorlabs</td>
 <td>F810SMA-780</td>
 <td></td>
 </tr>
 <tr>
 <td>Polarizing beam splitter cube</td>
 <td>Thorlabs</td>
 <td>GL15-B</td>
 <td></td>
 </tr>
 <tr>
 <td>&lambda;/4 wave plate</td>
 <td>Thorlabs</td>
 <td>WPQ10M-780</td>
 <td></td>
 </tr>
 <tr>
 <td>Beam expansion lenses</td>
 <td>Thorlabs</td>
 <td></td>
 <td></td>
 </tr>
 <tr>
 <td>Optical spectrometer</td>
 <td>Ocean Optics</td>
 <td>HR4000</td>
 <td></td>
 </tr>
 <tr>
 <td>Optical fiber</td>
 <td>Ocean Optics</td>
 <td></td>
 <td></td>
 </tr>
 <tr>
 <td>Low pressure NMR tube</td>
 <td>Wilmad</td>
 <td>513-7LPV-7</td>
 <td></td>
 </tr>
 <tr>
 <td>5mm NMR tube</td>
 <td>Sigma-Aldrich</td>
 <td>HX58.1</td>
 <td></td>
 </tr>
 <tr>
 <td>Helmholtz coils</td>
 <td>Phywe</td>
 <td>06960-00</td>
 <td></td>
 </tr>
 <tr>
 <td>Fused silica capillaries</td>
 <td>Polymicro</td>
 <td>TSG 250350</td>
 <td></td>
 </tr>
 </tbody>
</table>

hyperpolarized xenon for nmr and mri applications

Nuclear magnetic resonance (NMR) spectroscopy and imaging (MRI) suffer from intrinsic low sensitivity because even strong external magnetic fields of ~10 T generate only a small detectable net-magnetization of the sample at room temperature 1. Hence, most NMR and MRI applications rely on the detection of molecules at relative high concentration (e.g., water for imaging of biological tissue) or require excessive acquisition times. This limits our ability to exploit the very useful molecular specificity of NMR signals for many biochemical and medical applications. However, novel approaches have emerged in the past few years: Manipulation of the detected spin species prior to detection inside the NMR/MRI magnet can dramatically increase the magnetization and therefore allows detection of molecules at much lower concentration 2.
Here, we present a method for polarization of a xenon gas mixture (2-5% Xe, 10% N2, He balance) in a compact setup with a ca. 16000-fold signal enhancement. Modern line-narrowed diode lasers allow efficient polarization 7 and immediate use of gas mixture even if the noble gas is not separated from the other components. The SEOP apparatus is explained and determination of the achieved spin polarization is demonstrated for performance control of the method.
The hyperpolarized gas can be used for void space imaging, including gas flow imaging or diffusion studies at the interfaces with other materials 8,9. Moreover, the Xe NMR signal is extremely sensitive to its molecular environment 6. This enables the option to use it as an NMR/MRI contrast agent when dissolved in aqueous solution with functionalized molecular hosts that temporarily trap the gas 10,11. Direct detection and high-sensitivity indirect detection of such constructs is demonstrated in both spectroscopic and imaging mode.

Watch this Scientific Journal Video about Hyperpolarized Xenon for NMR and MRI Applications at JoVE.com

Hyperpolarized Xenon for NMR and MRI Applications

The production of hyperpolarized xenon by means of spin exchange optical pumping (SEOP) is described. This method yields a ~10000-fold enhancement of the nuclear spin polarization of Xe-129 and has applications in nuclear magnetic resonance spectroscopy and imaging. Examples of gas phase and solution state experiments are given.

Nuclear magnetic resonance (NMR) spectroscopy and imaging (MRI) suffer from intrinsic low sensitivity because even strong external magnetic fields of ~10 ...

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19.5K Views.  Leibniz-Institut für Molekulare Pharmakologie. The production of hyperpolarized xenon by means of spin exchange optical pumping (SEOP) is described. This method yields a ~10000-fold enhancement of the nuclear spin polarization of Xe-129 and has applications in nuclear magnetic resonance spectroscopy and imaging. Examples of gas phase and solution state experiments are given.

Video: Hyperpolarized Xenon for NMR and MRI Applications

Solid-state Graft Copolymer Electrolytes for Lithium Battery Applications

Battery safety has been a very important research area over the past decade. Commercially available lithium ion batteries employ low flash point (&lt;80 &deg;C), flammable, and volatile organic electrolytes. These organic based electrolyte systems are viable at ambient temperatures, but require a cooling system to ensure that temperatures do not exceed 80 &deg;C. These cooling systems tend to increase battery costs and can malfunction which can lead to battery malfunction and explosions, thus endangering human life. Increases in petroleum prices lead to a huge demand for safe, electric hybrid vehicles that are more economically viable to operate as oil prices continue to rise. Existing organic based electrolytes used in lithium ion batteries are not applicable to high temperature automotive applications. A safer alternative to organic electrolytes is solid polymer electrolytes. This work will highlight the synthesis for a graft copolymer electrolyte (GCE) poly(oxyethylene) methacrylate (POEM) to a block with a lower glass transition temperature (Tg) poly(oxyethylene) acrylate (POEA). The conduction mechanism has been discussed and it has been demonstrated the relationship between polymer segmental motion and ionic conductivity indeed has a Vogel-Tammann-Fulcher (VTF) dependence. Batteries containing commercially available LP30 organic (LiPF6 in ethylene carbonate (EC):dimethyl carbonate (DMC) at a 1:1 ratio) and GCE were cycled at ambient temperature. It was found that at ambient temperature, the batteries containing GCE showed a greater overpotential when compared to LP30 electrolyte. However at temperatures greater than 60 &deg;C, the GCE cell exhibited much lower overpotential due to fast polymer electrolyte conductivity and nearly the full theoretical specific capacity of 170 mAh/g was accessed.

Lithium ion batteries employ flammable and volatile organic electrolytes that are suitable for ambient temperature applications. A safer alternative to organic electrolytes are solid polymer batteries. Solid polymer batteries operate safely at high temperatures (&gt;120 &deg;C), thus making them applicable to high temperature applications such as deep oil drilling and hybrid electric vehicles. This paper will discuss (a) the polymer synthesis, (b) the polymer conduction mechanism, and (c) provide temperature cycling for both solid polymer and organic electrolytes.

Battery safety has been a very important research area over the past decade. Commercially available lithium ion batteries employ low flash point (&lt;80 ...

Characterization of Surface Modifications by White Light Interferometry: Applications in Ion Sputtering, Laser Ablation, and Tribology Experiments

In materials science and engineering it is often necessary to obtain quantitative measurements of surface topography with micrometer lateral resolution. From the measured surface, 3D topographic maps can be subsequently analyzed using a variety of software packages to extract the information that is needed.
In this article we describe how white light interferometry, and optical profilometry (OP) in general, combined with generic surface analysis software, can be used for materials science and engineering tasks. In this article, a number of applications of white light interferometry for investigation of surface modifications in mass spectrometry, and wear phenomena in tribology and lubrication are demonstrated. We characterize the products of the interaction of semiconductors and metals with energetic ions (sputtering), and laser irradiation (ablation), as well as ex situ measurements of wear of tribological test specimens.
Specifically, we will discuss:
<ol class="lroman">
	<li>Aspects of traditional ion sputtering-based mass spectrometry such as sputtering rates/yields measurements on Si and Cu and subsequent time-to-depth conversion.</li>
	<li>Results of quantitative characterization of the interaction of femtosecond laser irradiation with a semiconductor surface. These results are important for applications such as ablation mass spectrometry, where the quantities of evaporated material can be studied and controlled via pulse duration and energy per pulse. Thus, by determining the crater geometry one can define depth and lateral resolution versus experimental setup conditions.</li>
	<li>Measurements of surface roughness parameters in two dimensions, and quantitative measurements of the surface wear that occur as a result of friction and wear tests.</li>
</ol>
Some inherent drawbacks, possible artifacts, and uncertainty assessments of the white light interferometry approach will be discussed and explained.

White light microscope interferometry is an optical, noncontact and quick method for measuring the topography of surfaces. It is shown how the method can be applied toward mechanical wear analysis, where wear scars on tribological test samples are analyzed; and in materials science to determine ion beam sputtering or laser ablation volumes and depths.

In materials science and engineering it is often necessary to obtain quantitative measurements of surface topography with micrometer lateral resolution. ...

Detection and Recovery of Palladium, Gold and Cobalt Metals from the Urban Mine Using Novel Sensors/Adsorbents Designated with Nanoscale Wagon-wheel-shaped Pores

Developing low-cost, efficient processes for recovering and recycling palladium, gold and cobalt metals from urban mine remains a significant challenge in industrialized countries. Here, the development of optical mesosensors/adsorbents (MSAs) for efficient recognition and selective recovery of Pd(II), Au(III), and Co(II) from urban mine was achieved. A simple, general method for preparing MSAs based on using high-order mesoporous monolithic scaffolds was described. Hierarchical cubic Ia3d wagon-wheel-shaped MSAs were fabricated by anchoring chelating agents (colorants) into three-dimensional pores and micrometric particle surfaces of the mesoporous monolithic scaffolds. Findings show, for the first time, evidence of controlled optical recognition of Pd(II), Au(III), and Co(II) ions and a highly selective system for recovery of Pd(II) ions (up to ~95%) in ores and industrial wastes. Furthermore, the controlled assessment processes described herein involve evaluation of intrinsic properties (e.g., visual signal change, long-term stability, adsorption efficiency, extraordinary sensitivity, selectivity, and reusability); thus, expensive, sophisticated instruments are not required. Results show evidence that MSAs will attract worldwide attention as a promising technological means of recovering and recycling palladium, gold and cobalt metals.

Because of the importance and extensive use of palladium, gold and cobalt metals in high-technology equipment, their recovery and recycling constitute an important industrial challenge. The metal recovery system described herein is a simple, low-cost means for the effective detection, removal, and recovery of these metals from the urban mine.

Developing low-cost, efficient processes for recovering and recycling palladium, gold and cobalt metals from urban mine remains a significant challenge in ...

Use of a Multi-compartment Dynamic Single Enzyme Phantom for Studies of Hyperpolarized Magnetic Resonance Agents

Imaging of hyperpolarized substrates by magnetic resonance shows great clinical promise for assessment of critical biochemical processes in real time. Due to fundamental constraints imposed by the hyperpolarized state, exotic imaging and reconstruction techniques are commonly used. A practical system for characterization of dynamic, multi-spectral imaging methods is critically needed. Such a system must reproducibly recapitulate the relevant chemical dynamics of normal and pathological tissues. The most widely utilized substrate to date is hyperpolarized [1-13C]-pyruvate for assessment of cancer metabolism. We describe an enzyme-based phantom system that mediates the conversion of pyruvate to lactate. The reaction is initiated by injection of the hyperpolarized agent into multiple chambers within the phantom, each of which contains varying concentrations of reagents that control the reaction rate. Multiple compartments are necessary to ensure that imaging sequences faithfully capture the spatial and metabolic heterogeneity of tissue. This system will aid the development and validation of advanced imaging strategies by providing chemical dynamics that are not available from conventional phantoms, as well as control and reproducibility that is not possible in vivo.

A multi-compartment dynamic phantom is used to simulate some biology of interest for metabolic studies using hyperpolarized magnet resonance agents.

Imaging of hyperpolarized substrates by magnetic resonance shows great clinical promise for assessment of critical biochemical processes in real time. Due ...

Three-dimensional Particle Tracking Velocimetry for Turbulence Applications: Case of a Jet Flow

3D-PTV is a quantitative flow measurement technique that aims to track the Lagrangian paths of a set of particles in three dimensions using stereoscopic recording of image sequences. The basic components, features, constraints and optimization tips of a 3D-PTV topology consisting of a high-speed camera with a four-view splitter are described and discussed in this article. The technique is applied to the intermediate flow field (5 &#60;x/d &#60;25) of a circular jet at Re &#8776; 7,000. Lagrangian flow features and turbulence quantities in an Eulerian frame are estimated around ten diameters downstream of the jet origin and at various radial distances from the jet core. Lagrangian properties include trajectory, velocity and acceleration of selected particles as well as curvature of the flow path, which are obtained from the Frenet-Serret equation. Estimation of the 3D velocity and turbulence fields around the jet core axis at a cross-plane located at ten diameters downstream of the jet is compared with literature, and the power spectrum of the large-scale streamwise velocity motions is obtained at various radial distances from the jet core.

A three-dimensional particle tracking velocimetry (3D-PTV) system based on a high-speed camera with a four-view splitter is described here. The technique is applied to a jet flow from a circular pipe in the vicinity of ten diameters downstream at Reynolds number Re &#8776; 7,000.

3D-PTV is a quantitative flow measurement technique that aims to track the Lagrangian paths of a set of particles in three dimensions using stereoscopic ...

Colloidal Synthesis of Nanopatch Antennas for Applications in Plasmonics and Nanophotonics

We present a method for colloidal synthesis of silver nanocubes and the use of these in combination with a smooth gold film, to fabricate plasmonic nanoscale patch antennas. This includes a detailed procedure for the fabrication of thin films with a well-controlled thickness over macroscopic areas using layer-by-layer deposition of polyelectrolyte polymers, namely poly(allylamine) hydrochloride (PAH) and polystyrene sulfonate (PSS). These polyelectrolyte spacer layers serve as a dielectric gap in between silver nanocubes and a gold film. By controlling the size of the nanocubes or the gap thickness, the plasmon resonance can be tuned from about 500 nm to 700 nm. Next, we demonstrate how to incorporate organic sulfo-cyanine5 carboxylic acid (Cy5) dye molecules into the dielectric polymer gap region of the nanopatch antennas. Finally, we show greatly enhanced fluorescence of the Cy5 dyes by spectrally matching the plasmon resonance with the excitation energy and the Cy5 absorption peak. The method presented here enables the fabrication of plasmonic nanopatch antennas with well-controlled dimensions utilizing colloidal synthesis and a layer-by-layer dip-coating process with the potential for low cost and large-scale production. These nanopatch antennas hold great promise for practical applications, for example in sensing, ultrafast optoelectronic devices and for high-efficiency photodetectors.

A protocol for the colloidal synthesis of silver nanocubes and fabrication of plasmonic nanoscale patch antennas with sub-10 nm gaps is presented.

We present a method for colloidal synthesis of silver nanocubes and the use of these in combination with a smooth gold film, to fabricate plasmonic ...

Fabrication of Polymer Microspheres for Optical Resonator and Laser Applications

This paper describes three methods of preparing fluorescent microspheres comprising &#960;-conjugated or non-conjugated polymers: vapor diffusion, interface precipitation, and mini-emulsion. In all methods, well-defined, micrometer-sized spheres are obtained from a self-assembling process in solution. The vapor diffusion method can result in spheres with the highest sphericity and surface smoothness, yet the types of the polymers able to form these spheres are limited. On the other hand, in the mini-emulsion method, microspheres can be made from various types of polymers, even from highly crystalline polymers with coplanar, &#960;-conjugated backbones. The photoluminescent (PL) properties from single isolated microspheres are unusual: the PL is confined inside the spheres, propagates at the circumference of the spheres via the total internal reflection at the polymer/air interface, and self-interferes to show sharp and periodic resonant PL lines. These resonating modes are so-called "whispering gallery modes" (WGMs). This work demonstrates how to measure WGM PL from single isolated spheres using the micro-photoluminescence (&#181;-PL) technique. In this technique, a focused laser beam irradiates a single microsphere, and the luminescence is detected by a spectrometer. A micromanipulation technique is then used to connect the microspheres one by one and to demonstrate the intersphere PL propagation and color conversion from coupled microspheres upon excitation at the perimeter of one sphere and detection of PL from the other microsphere. These techniques, &#181;-PL and micromanipulation, are useful for experiments on micro-optic application using polymer materials.

Protocols for the synthesis of microspheres from polymers, the manipulation of microspheres, and micro-photoluminescence measurements are presented.

This paper describes three methods of preparing fluorescent microspheres comprising &#960;-conjugated or non-conjugated polymers: vapor diffusion, ...

Protocol for the Evaluation of MRI Artifacts Caused by Metal Implants to Assess the Suitability of Implants and the Vulnerability of Pulse Sequences

As the number of magnetic resonance imaging (MRI) scanners and patients with medical implants is constantly growing, radiologists increasingly encounter metallic implant-related artifacts in MRI, resulting in reduced image quality. Therefore, the MRI suitability of implants in terms of artifact volume, as well as the development of pulse sequences to reduce image artifacts, are becoming more and more important. Here, we present a comprehensive protocol which allows for a standardized evaluation of the artifact volume of implants on MRI. Furthermore, this protocol can be used to analyze the vulnerability of different pulse sequences to artifacts. The proposed protocol can be applied to T1- and T2-weighted images with or without fat-suppression and all passive implants. Furthermore, the procedure enables the separate and three-dimensional identification of signal loss and pile-up artifacts. As previous investigations differed greatly in evaluation methods, the comparability of their results was limited. Thus, standardized measurements of MRI artifact volumes are necessary to provide better comparability. This may improve the development of the MRI suitability of implants and better pulse sequences to finally improve patient care.

We describe a standardized method to evaluate magnetic resonance imaging artifacts caused by implants to estimate the suitability of the implants for magnetic resonance imaging and/or the vulnerability of different pulse sequences to metallic artifacts simultaneously.

As the number of magnetic resonance imaging (MRI) scanners and patients with medical implants is constantly growing, radiologists increasingly encounter ...

Fabrication of Superhydrophobic Metal Surfaces for Anti-Icing Applications

Several ways to produce superhydrophobic metal surfaces are presented in this work. Aluminum was chosen as the metal substrate due to its wide use in industry. The wettability of the produced surface was analyzed by bouncing drop experiments and the topography was analyzed by confocal microscopy. In addition, we show various methodologies to measure its durability and anti-icing properties. Superhydrophobic surfaces hold a special texture that must be preserved to keep their water-repellency. To fabricate durable surfaces, we followed two strategies to incorporate a resistant texture. The first strategy is a direct incorporation of roughness to the metal substrate by acid etching. After this surface texturization, the surface energy was decreased by silanization or fluoropolymer deposition. The second strategy is the growth of a ceria layer (after surface texturization) that should enhance the surface hardness and corrosion resistance. The surface energy was decreased with a stearic acid film.
The durability of the superhydrophobic surfaces was examined by a particle impact test, mechanical wear by lateral abrasion, and UV-ozone resistance. The anti-icing properties were explored by studying the ability to repeal subcooled water, freezing delay, and ice adhesion.

We illustrate several methodologies to produce superhydrophobic metal surfaces and to explore their durability and anti-icing properties.

Several ways to produce superhydrophobic metal surfaces are presented in this work. Aluminum was chosen as the metal substrate due to its wide use in ...

Controllable Nucleation of Cavitation from Plasmonic Gold Nanoparticles for Enhancing High Intensity Focused Ultrasound Applications

In this study, plasmonic gold nanoparticles were simultaneously exposed to pulsed near-infrared laser light and high intensity focused ultrasound (HIFU) for the controllable nucleation of cavitation in tissue-mimicking gel phantoms. This in vitro protocol was developed to demonstrate the feasibility of this approach, for both enhancement of imaging and therapeutic applications for cancer. The same apparatus can be used for both imaging and therapeutic applications by varying the exposure duration of the HIFU system. For short duration exposures (10 &#181;s), broadband acoustic emissions were generated through the controlled nucleation of inertial cavitation around the gold nanoparticles. These emissions provide direct localization of nanoparticles. For future applications, these particles may be functionalized with molecular-targeting antibodies (e.g. anti-HER2 for breast cancer) and can provide precise localization of cancerous regions, complementing routine diagnostic ultrasound imaging. For continuous wave (CW) exposures, the cavitation activity was used to increase the localized heating from the HIFU exposures resulting in larger thermal damage in the gel phantoms. The acoustic emissions generated from inertial cavitation activity during these CW exposures was monitored using a passive cavitation detection (PCD) system to provide feedback of cavitation activity. Increased localized heating was only achieved through the unique combination of nanoparticles, laser light and HIFU. Further validation of this technique in pre-clinical models of cancer is necessary.

This protocol demonstrates the controllable nucleation of cavitation in gel phantoms, through simultaneous exposure to both near-infrared pulsed laser light and high intensity focused ultrasound (HIFU). The cavitation activity can then be used for enhancing imaging and/or therapeutic uses of HIFU.

In this study, plasmonic gold nanoparticles were simultaneously exposed to pulsed near-infrared laser light and high intensity focused ultrasound (HIFU) ...