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Ternary Porphyrinato HfIVand ZrIVPolyoxometalate Complexes

Alexander Falber, Benjamin P. Burton-Pye, Ivana Radivojevic, Louis Todaro, Raihan Saleh, Lynn C. Francesconi, Charles Michael Drain
2009 European Journal of Inorganic Chemistry  
doi:10.1002/ejic.200900284 pmid:20543903 pmcid:PMC2883273 fatcat:ksffk4l66fbbjfmtkqococzdnm

p-SCN-Bn-HOPO: A Superior Bifunctional Chelator for 89Zr ImmunoPET

Melissa A. Deri, Shashikanth Ponnala, Paul Kozlowski, Benjamin P. Burton-Pye, Huseyin T. Cicek, Chunhua Hu, Jason S. Lewis, Lynn C. Francesconi
2015 Bioconjugate chemistry  
Zirconium-89 has an ideal half-life for use in antibody-based PET imaging; however, when used with the chelator DFO, there is an accumulation of radioactivity in the bone, suggesting that the 89 Zr 4+ cation is being released in vivo. Therefore, a more robust chelator for 89 Zr could reduce the in vivo release and the dose to nontarget tissues. Evaluation of the ligand 3,4,3-(LI-1,2-HOPO) demonstrated efficient binding of 89 Zr 4+ and high stability; therefore, we developed a bifunctional
more » ... tive, p-SCN-Bn-HOPO, for conjugation to an antibody. A Zr-HOPO crystal structure was obtained showing that the Zr is fully coordinated by the octadentate HOPO ligand, as expected, forming a stable complex. p-SCN-Bn-HOPO was synthesized through a novel pathway. Both p-SCN-Bn-HOPO and p-SCN-Bn-DFO were conjugated to trastuzumab and radiolabeled with 89 Zr. Both complexes labeled efficiently and achieved specific activities of approximately 2 mCi/mg. PET imaging studies in nude mice with BT474 tumors (n = 4) showed good tumor uptake for both compounds, but with a marked decrease in bone uptake for the 89 Zr-HOPO-trastuzumab images. Biodistribution data confirmed the lower bone activity, measuring 17.0%ID/g in the bone at 336 h for 89 Zr-DFO-trastuzumab while 89 Zr-HOPO-trastuzumab only had 2.4%ID/g. We successfully synthesized p-SCN-Bn-HOPO, a bifunctional derivative of 3,4,3-(LI-1,2-HOPO) as a potential chelator for 89 Zr. In vivo studies demonstrate the successful use of 89 Zr-HOPO-trastuzumab to image BT474 breast cancer with low background, good tumor to organ contrast, and, importantly, very low bone uptake. The reduced bone uptake seen with 89 Zr-HOPO-trastuzumab suggests superior stability of the 89 Zr-HOPO complex. Graphical Abstract INTRODUCTION Antibodies possess exquisite specificity and affinity for their antigens, 1 and as a consequence, positron emission tomography (PET) using targeted antibodies is a molecular imaging technique at the forefront of cancer diagnosis and treatment management. 1-6 Zirconium-89 ( 89 Zr), a positron-emitting radionuclide, possesses excellent physical properties for PET imaging when paired with antibodies, namely, an ideal 78.41 h half-life and low energy positron (β avg = 395.5 keV), and is readily attracting attention for this purpose. 7-14 In the past several years, a wide variety of preclinical studies have been published 15-21 and a number of 89 Zr-based antibody imaging agents have been translated into the clinic, including a number of current clinical trials in the US alone. [2] [3] [4] [22] [23] [24] [25] These clinical studies and all preclinical studies use the current standard bifunctional chelator for 89 Zr: desferrioxamine B (DFO). 16 DFO, a natural bacterial siderophore, is a hexadentate ligand with three hydroxamate groups which provide six oxygen donors for metal binding. 26 It possesses an amine tail that can be derivatized for facile conjugation to antibodies and other biomolecular vectors. Although image quality is generally very good, DFO is not the optimal ligand for 89 Zr. This is revealed by the observed uptake of radioactivity in the bone. 7, 16, 27, 28 This uptake is evidence of in vivo release of 89 Zr 4+ from the chelator. When unbound, the osteophilic 89 Zr 4+ cation is readily mineralized into the skeleton. 28,29 This accumulation of 89 Zr 4+ in the bone can dramatically increase radiation dose to the bone marrow, an especially radiosensitive tissue. While the extent of this uptake is less established in the clinic, it is still being investigated and may be of particular concern since 89 Zr-immunoPET agents have found specific use in the detection of bone metastasis. 30 This concern over in vivo stability sparks the need to develop an improved bifunctional chelator for Zr that will significantly improve 89 Zr-antibody PET imaging by providing an Deri et al. improved alternative to DFO, reducing absorbed doses to healthy tissues and therefore safer PET imaging, and enhanced image quality. Recently, there has been a surge of interest in the development of an alternative chelator for 89 Zr 4+ to replace DFO, with several novel ligand systems being reported within the past year or so (Figure 1) . [31] [32] [33] [34] [35] [36] [37] While multiple studies demonstrate the issue of bone uptake seen with 89 Zr-DFO complexes and stress the need for improved chelators, 16, 27, 28, 34 the first investigation toward designing a better chelator of Zr 4+ came from Guérard et al. 38 This work examined the coordination chemistry of the Zr 4+ cation and confirmed the advantage of an octa-coordinate zirconium complex as Zr 4+ was shown to preferentially form complexes with eight oxygen donors contained within four bidentate hydroxamate groups. This study opened the door for the investigation of octadentate ligands to replace the hexadentate DFO chelator with the goal of improving in vivo stability. Thus, far, however, there has been no reporting of a new ligand for 89 Zr 4+ that has been demonstrated to be viable in vivo for a sufficient length of time for antibody imaging. Several potential ligands require additional development while others simply require further evaluation. Herein, we present the first successful demonstration of an alternative chelator for 89 Zr that includes PET imaging and biodistribution data that shows improved stability over DFO across a period of several days in vivo. We investigated the potential of a nonhydroxamate-based ligand-3,4,3-(LI-1,2-HOPO) or HOPO-which has four 1,2-hydroxypyridinone groups for metal binding and comes from the actinide sequestration literature. 39 As we postulated, the HOPO ligand labeled efficiently and 89 Zr-HOPO exhibited equal or superior stability compared to 89 Zr-DFO in all chemical and biological assays. 34 Not only did the 3,4,3-(LI-1,2-HOPO) ligand show tremendous promise in our preliminary evaluation, but even more recently, stability constants for Zr-HOPO were determined to be on the order of log β = 43, the highest recorded for any Zr complex which attests to the superior stability. 40 Therefore, we endeavored to develop a bifunctional variant of the HOPO ligand for further evaluation and application in antibodybased PET imaging. The result of this venture is the bifunctional chelator: p-SCN-Bn-HOPO ( Figure 2 ). This molecule is the HOPO ligand with a para-benzyl-isothiocyanate pendant arm added to one of the secondary amides in order to be directly comparable with the currently most used bifunctional chelator: p-SCN-Bn-DFO ( Figure 2 ). We also report the crystal structure of Zr-HOPO which corroborates the high stability.
doi:10.1021/acs.bioconjchem.5b00572 pmid:26550847 pmcid:PMC4962612 fatcat:prfuk5wdtvf6ja6hc3d67jq4fm

Photochemical behavior of the quadruply metal-metal bonded [Tc2Cl8]2− anion in acetonitrile

Benjamin P. Burton-Pye, Frederic Poineau, Julie Bertoia, Kenneth R. Czerwinski, Lynn C. Francesconi, Alfred P. Sattelberger
2016 Inorganica Chimica Acta  
The photochemical behavior of [Tc 2 Cl 8 ] 2was investigated in acetonitrile. The speciation of Tc before and after irradiation at 254 nm was performed by UV-visible spectroscopy. Upon irradiation at 254 nm, [Tc 2 Cl 8 ] 2was unstable, the scission of the Tc Tc unit occurred and the complex [TcCl 4 (CH 3 CN) 2 ] was identified. The disappearance rate of [M 2 Cl 8 ] 2-(M = Tc, Re) under irradiation has been measured and was ~7.5 time faster for Tc than for Re.
doi:10.1016/j.ica.2016.09.041 fatcat:ssbx37stovhdlc7lwcsegnyxge

Zirconium(IV) and Hafnium(IV) Porphyrin and Phthalocyanine Complexes as New Dyes for Solar Cell Devices

Ivana Radivojevic, Giorgio Bazzan, Benjamin P. Burton-Pye, Kemakorn Ithisuphalap, Raihan Saleh, Michael F. Durstock, Lynn C. Francesconi, Charles Michael Drain
2012 Journal of Physical Chemistry C  
Metalloporphyrin and metallophthalocyanine dyes ligating Hf(IV) and Zr(IV) ions bind to semiconductor oxide surfaces such as TiO 2 via the protruding group IV metal ions. The use of oxophylic metal ions with large ionic radii that protrude from the macrocycle is a unique mode of attaching chromophores to oxide surfaces in the design of dye-sensitized solar cells (DSSCs). Our previous report on the structure and physical properties of ternary complexes wherein the Hf(IV) and Zr(IV) ions are
more » ... ed to both a porphyrinoid and to a defect site on a polyoxometalate (POM) represents a model for this new way of binding dyes to oxide surfaces. The Zr(IV) and Hf(IV) complexes of 5,10,15,20-tetraphenylporphyrin (TPP) with two ligated acetates, (TPP)Hf(OAc) 2 and (TPP)Zr(OAc) 2 , and the corresponding metallophthalocyanine (Pc) diacetate complexes, (Pc)Hf(OAc) 2 and (Pc)Zr(OAc) 2 , were evaluated as novel dyes for the fabrication of dye-sensitized solar cells. Similarly to the ternary complexes with the POM, the oxide surface replaces the acetates to affect binding. In DSSCs the Zr(IV) phthalocyanine dye performs better than the Zr(IV) porphyrin dye, and reaches an overall efficiency of ~ 1.0%. The Hf(IV) dyes are less efficient. The photophysical properties of these complexes in solution suggested energetically favorable injection of electrons into the conduction band of TiO 2 semiconductor nanoparticles, as well as a good band gap match with I 3 − /I − pair in liquid 1-butyl-3-methyl imidazolium iodide. The combination of blue absorbing TPP with the red absorbing Pc complexes can increase the absorbance of solar light in the device; however, the overall conversion efficiency of DSSCs using TiO 2 nanoparticles treated with a mixture of both Zr(IV) complexes is comparable, but not greater than, the single (Pc)Zr. Thus, surface bound (TPP)Zr increases the absorbance in blue region of the spectra, but at the cost of diminished absorbance in the red in this DSSC architecture.
doi:10.1021/jp301853d pmid:22962625 pmcid:PMC3433074 fatcat:vpjsg6zyzbes5dioel7qxspl4m

Copernicus Sentinel-2A Calibration and Products Validation Status

Ferran Gascon, Catherine Bouzinac, Olivier Thépaut, Mathieu Jung, Benjamin Francesconi, Jérôme Louis, Vincent Lonjou, Bruno Lafrance, Stéphane Massera, Angélique Gaudel-Vacaresse, Florie Languille, Bahjat Alhammoud (+11 others)
2017 Remote Sensing  
As part of the Copernicus programme of the European Union (EU), the European Space Agency (ESA) has developed and is currently operating the Sentinel-2 mission that is acquiring high spatial resolution optical imagery. This paper provides a description of the calibration activities and the current status of the mission products validation activities. Measured performances, from the validation activities, cover both Top-Of-Atmosphere (TOA) and Bottom-Of-Atmosphere (BOA) products. Results
more » ... d in this paper show the good quality of the mission products both in terms of radiometry and geometry and provide an overview on next mission steps related to data quality aspects. between minimizing cloud cover and ensuring suitable sun illumination. An overview of the MSI imaging payload is provided in the following section. The Sentinel-2 satellites will systematically acquire observations over land and coastal areas from −56 ° to 84 ° latitude including islands larger 100 km 2 , EU islands, all other islands less than 20 km from the coastline, the whole Mediterranean Sea, all inland water bodies and all closed seas. Over specific calibration sites, for example DOME-C in Antarctica, additional observations will be made. The two satellite units will work on opposite sides of the orbit. Sentinel-2A launch took place in June 2015 and Sentinel-2B is foreseen beginning 2017. Therefore, this paper focuses only on the performances achieved by Sentinel-2A. The availability of products with good data quality performances (both in terms of radiometry and geometry accuracies) has a paramount importance for many applications. This is indeed a key enabling factor for an easier exploitation of time-series, inter-comparison of measurements from different sensors or detection of changes in the landscape. Calibration and validation (Cal/Val) corresponds to the process of updating and validating on-board and on-ground configuration parameters and algorithms to ensure that the product data quality requirements are met. This paper provides a description of the calibration activities and the current status, one year after Sentinel-2A launch, of the mission products validation activities. Measured performances, derived from the validation activities, have been estimated for both Top-Of-Atmosphere (TOA) and Bottom-Of-Atmosphere (BOA) products (referred respectively as Level-1 and Level-2A and further described later in this paper). . Multi-Spectral Instrument Overview This section provides a brief overview of Sentinel-2 Multi-Spectral Instrument (MSI). It aims at giving to the reader the basis required to fully understand the measured performances and the Calibration and Validation (Cal/Val) approach. MSI Design The MSI instrument design has been driven by the large swath requirement together with the demanding geometrical and spectral performances of the measurements. It is based on a push-broom concept, featuring a Three-Mirror Anastigmatic (TMA) telescope feeding two focal planes spectrally separated by a dichroic filter, as shown on Figure 1 . One focal plane includes the Visible and Near-Infrared (VNIR) bands and the other one the Short-Wave Infrared (SWIR) bands. Figure 1. MSI internal configuration. On the left, full instrument view and optical path construction to the SWIR/VNIR (see §2.2) splitter and focal planes. Spectral Bands and Resolution Preprints ( | NOT PEER-REVIEWED | Posted: Overlapping area = 98 pixels @ 20m 10 bands B/H cross-detector B/H cross-band Nb pixels / detector module: 2592 (10m) or 1296 (20m -60m) Satellite track YLOS XLOS ZLOS ψX ψY Viewing direction Preprints ( | NOT PEER-REVIEWED | Posted:
doi:10.3390/rs9060584 fatcat:fglsduu6g5bjpd6nmxpspa2hfy

Author Index

2015 Neuropsychopharmacology  
W193 France, Charles . . . . . . . . . . . . . . . . . . . . . . . . . . . .M250 Francesconi, Marta . . . . . . . . . . . . . . . . . . . . . . . .  ...  M64 Fraser, Benjamin H. . . . . . . . . . . . . . . . . . . . . . . . . . T61 Fraser-Spears, Rheaclare. . . . . . . . . . . . . . . . . . . . . . . T61 Frazier, C.  ... 
doi:10.1038/npp.2015.328 fatcat:b4jcs54oivfzhjj3enmox3hwpq


2019 Zeitschrift für Romanische Philologie  
Enrique Pato Principales rasgos gramaticales del español de Panamá  1042 Wolfgang Schweickard Ven. schena / schina  1074 Forschungsbericht Martin Hummel / Adrian Chircu / Jairo Javier García Sánchez / Benjamín  ...  Edizione critica a cura di Luca Cadioli (Francesco Zambon)  1158 Davide Mastrantonio, Latinismi sintattici nella prosa del Duecento, Presentazione di Maurizio Dardano (Alessio Ricci)  1163 Giampaolo Francesconi  ... 
doi:10.1515/zrp-2019-frontmatter4 fatcat:zsswsis2pvannac3qy3upzxemu

Bioaccumulation, biotransformation and trophic transfer of arsenic in the aquatic food chain

M. Azizur Rahman, Hiroshi Hasegawa, Richard Peter Lim
2012 Environmental Research  
AsC (Lawrence et al., 1986; Benjamin et al., 1987) and arsenoribosides (AsR) (Kirby et al., 2002) have also been found in marine animals (fish, shellfish, lobsters, shrimp etc.).  ...  A number of other studies have shown that marine algae produce AsS (Cooney and Benson, 1980; Edmonds and Francesconi, 1981; Edmonds et al., 1982; Edmonds and Francesconi, 1983; Francesconi et al., 1998  ...  ., 2004 ) Trimethylarsine acid TMAA (CH 3 ) 3 As Marine animals (Anderson and Bruland, 1991; Francesconi and Edmonds, 1996; Francesconi et al., 2000) (Mürer et al., 1992) Arsenobetaine AsB (CH 3  ... 
doi:10.1016/j.envres.2012.03.014 pmid:22534144 fatcat:nlhp33bwdzer5a2ymk3nkct6k4

Page 376 of Journal of Gerontology Vol. 9, Issue 3 [page]

1954 Journal of Gerontology  
Lippi-Francesconi, P. L.: Trattamento di sindromi schizofreniche col siero citotossico secondo Bogomoletz. Riv. Patol. nerv. ment., 74: 247-248, 1953. Lyon, J. B., Jr., M. T. Dowling, and P. F.  ...  RESPIRATORY SYSTEM Benjamin, B.: Tuberculosis and social condi- tions in the metropolitan boroughs of London. Brit. J. Tuberc., 47: Jan. 1953. Abstr: P.I., 20: No. 190, 1954. Bernard, E., and A.  ... 

Page 96 of American Society for Microbiology. ASM News Vol. 42, Issue 2 [page]

1976 American Society for Microbiology. ASM News  
FRANCESCONI and OWEN B. WEEKS. Research Center, New Mexico State Univ. Growth and Biochemical Characteristics of a Detachment Variant of CHO Cells. BENJAMIN J. BARNHART, ALAN G. ATHERLY, and PAUL M.  ... 

Page 141 of Notes and Queries Vol. 6, Issue 106 [page]

1920 Notes and Queries  
Benjamin Blayney, D.D. — Bibliography of Lepers in England—De Quincey or Quincy—Martyn and Readon Families—Anathema Cup—Garnham Family— Reference Wanted—-Author of Quotations Wanted, 150: REPLIES :—Prince  ...  Carlo Gerini ho ricevuto da Mylord Caledon per mano del suo Mrd. di casa la suddetta somma di zecchini dugento quaranta cinque {fiorentini p[paoli] 63 per saldo del prezzo dei suddetti quadri Frances.[ =francesconi  ... 

Page 136 of Chemical Engineering Vol. 30, Issue 3 [page]

1924 Chemical Engineering  
., Antwerp, Benjamin Moore & Co. MANGANESE ORE—2?,200 tons, Janeiro, U. S. Steel Products Co.  ...  Francesconi & Co.; 7% bbl, Hull, Order. Waste—100 bbl., Hull, J. C. Francesconi & Co. PHOSPHATE — 1,700 be., Hollingshurst Co. PLUMBAGO—156 bbl., Johns, National Aberdeen, J.  ... 

Index of authors

2004 Journal of the American Society for Mass Spectrometry  
WODpm 04:40 Francesconi, Kevin A. .............................. WPC 039 Franciotti, Maurizio .................................. WPR 327 Francis, Anthony .......................................  ...  WPS 355 Figard, Benjamin J ..................................... TPE 086 Filén, Jan-Jonas ........................................MPW 437 Fillet, Marianne .........................................  ... 
doi:10.1016/j.jasms.2004.04.021 fatcat:avvpthfq6bftppeg4szhph3jam

Temporary employment, job satisfaction and subjective well-being

Chris Dawson, Michail Veliziotis, Benjamin Hopkins
2014 Economic and Industrial Democracy  
., 2005; Bardasi and Francesconi, 2004; Booth et al., 2002) .  ...  Rodriguez, 2002; Bardasi and Francesconi, 2004) . There are some important reasons why the relationship between temporary contracts and well-being may not be unambiguously negative.  ...  Benjamin Hopkins is Lecturer in Work and Employment at the University of Leicester. His research interests include migration, temporary work, and the transitions of young people into employment.  ... 
doi:10.1177/0143831x14559781 fatcat:ghm73eoy6jeohg72slbhtpdgje

Page 755 of Journal of Mass Spectrometry Vol. 35, Issue 6 [page]

2000 Journal of Mass Spectrometry  
Davis, Ca 95616, USA Int J Mass Spectrom 2000 196 259 Identification of arsenosugars at the picogram level using nanoelectrospray quadrupole time-of-flight mass spectrometry Pergantis SA, Wangkarn S, Francesconi  ...  Santiago de Compostela, Spain J Anal Toxicol 2000 24 (1) 66 Solvent effects on the conformation of the transmembrane peptide gramicidin A: Insights from electrospray ionization mass spectrometry Bouchard M, Benjamin  ... 
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