Up until 2019, Dr. Crans had published 201 peer-reviewed manuscripts with an H-index of 56 and >8000 citations.
Prior to 2010 Dr. Crans had published 138 peer reviewed manuscripts that can be found through the link.
In 2013, papers from Dr. Crans’ lab have had an editorial in Dalton Transactions (DaltonTrans 2013,42, p11744) and featured on the cover of The New Journal of Chemistry (Lemons2013NJCVO2Catecholate) and The Journal of Organic Chemistry!
The goddess Vanadis is shown with her hair in the shapes of protein parts of regulatory phosphatases symbolizing the complexities of mode of action of vanadium compounds. Vanadium-based antidiabetic agents are reviewed in terms of their chemical and physical properties and how structure is associated with function. The inhibition of protein phosphatase takes center stage because of the transition-state inhibitory effects of vanadates and organic vanadates and their resulting antidiabetic effects. Dr. Crans is the recipient of the 2015 Cope Scholar Award. Cover reported December 18, 2015 for the Journal of Organic chemistry (American Chemical Society). Painting by Kaitlin Doucette.
209. “Effects of vanadium(IV) compounds on plasma membrane lipids lead to G protein-coupled receptor signal transduction” Duaa Althumairy, Heide A. Murakami, Dongmei Zhang, B. George Barisas, Deborah A. Roess, Debbie C. Crans. Journal of Bioinorganic Chemistry, 2020.
208. “Vanadium science: chemistry, catalysis, materials, biological and medicinal studies” Debbie C. Crans, Dinorah Gambino, Susana B. Etcheverry. New Journal of Chemistry, 2019.
207. “The First-Row Transition Metals in the Periodic Table of Medicine” Cameron Van Cleave and Debbie C. Crans. Inorganics, 2019.
206. “Organometallic and coordination rhenium compounds and their potential in cancer therapy” Elisabeth B. Bauer, Allison A. Haase, Debbie C. Crans, Fritz E. Kühn. Coordination Chemistry Reviews, 2019.
205. “Speciation and toxicity of rhenium salts, organometallics and coordination complexes” Allison A. Haase, Elisabeth B. Bauer, Fritz E. Kühn, Debbie C. Crans. Coordination Chemistry Reviews, 2019.
204. “A Transition-State Perspective on Y-Family DNA Polymerase eta Fidelity in Comparison with X-Family DNA polymerases lambda and beta” Keriann Oertell, Jan Florian, Pouya Haratipour, Debbie C. Crans, Boris A. Kashemirov, Samuel H. Wilson, Charles E. McKenna, Myron F. Goodman. Biochemistry, 2019.
203. “Hydrophobicity May Enhance Membrane Affinity and Anti-Cancer Effects of Schiff Base Vanadium (V) Catecholate Complexes” Debbie C. Crans, Jordan T. Koehn, Stephanie M. Petry, Caleb M. Glover, Asanka Wijetunga, Ravider Kaur, Aviva Levina, and Peter A. Lay. Dalton Transactions, 2019. (Featured on the inside back cover of Dalton Transactions, vol 48)
202. “Investigating Substrate Analogs for Mycobacterial MenJ: Truncated and Partially Saturated Menaquinones” Jordan T. Koehn, Cheryle N. Beuning, Benjamin J. Peters, Sara K. Dellinger, Cameron Van Cleave, Dean C. Crick, and Debbie C. Crans. Biochemistry, 2019. Featured in Biochemistry Newsflash.
201. “Decavanadate Inhibits Mycobacterial Growth More Potently Than Other Oxovanadates” Nuttaporn Samart, Zeyad Arhoums, Santosh Kumar, Heide A. Murakami, Dean C. Crick, and Debbie C. Crans. Frontiers in Chemistry, 2018.
200. “Synthesis and Characterization of Partially and Fully Saturated Menaquinone Derivatives” Jordan T. Koehn, Dean C. Crick, Debbie C. Crick. ACS Omega, 2018, 3 (11), pp 14889-149.
199. “Mycobacterial MenJ: An Oxidoreductase Involved in Menaquinone Biosynthesis” Ashutosh Upahyay, Santosh Kumar, Steven A. Rooker, Jordan T. Koehn, Debbie C. Crans, Michael R. McNeil, J. Shaun Lott, Dean C. Crick. ACS Chemical Biology, 2018, 13 (9), pp 2498-2507.
198. “Coordination environment changes of the vanadium in vanadium-dependent haloperoxidase enzymes” Craig C. McLauchlan, Heide A. Murakami, Craig A. Wallance, and Debbie C. Crans. J. Inorg. Biochem., 2018, 186, pp 267-279.
197. “Structure Dependence of Pyridine and Benzene Derivatives on Interactions with Model Membranes” Benjamin J. Peters, Cameron Van Cleave, Allison A. Haase, John Peter B. Hough, Keisha A. Giffen-Kent, Gabriel M. Cardiff, Audra Goach Sostarecz, Dean C. Crick, and Debbie C. Crans. Langmuir, 2018, 34 (30), pp 8939-8951.
196. “Probing of ferrocenylanilines on model micelle/reverse micelle membrane and their enhanced reactivity for reactive oxidants” Ataf A. Altaf, Amin Badshah, Bahjan Lal, Shahzad Murtaza, Pabitra B. Chatterjee, Kamran Akbar, and Debbie C. Crans. Appl. Organometal Chem. 2018, 32:e4334.
195. “Measurement of Interpeptidic Cu(II) Exchange Rate Constants by Static Fluorescence Quenching of Tryptophan” Cheryle N. Beuning, Béatrice Mestre-Voegtlé, Peter Faller, Christelle Hureau, and Debbie C. Crans. Inorg. Chem., 2018, 57 (9), pp 4791-4794.
194. “A Synthetic Isoprenoid Lipoquinone, Menaquinone-2, Adopts a Folded Conformation in Solution and at a Model Membrane Interface” Jordan T. Koehn, Estela S. Magallanes, Benjamin J. Peters, Cheryle N. Beuning, Allison A. Haase, Michelle J. Zhu, Christopher D. Rithner, Dean C. Crick, and Debbie C. Crans. J. Org. Chem., 2018, 83 (1), pp 275–288.
193. “Multi-modal Potentiation of Oncolytic Virotherapy by Vanadium Compounds” Mohammed Selman, Christopher Rousso, Anabel Bergeron, Hwan Hee Son, Ramya Krishnan, Nader A. El-Sayes, Oliver Varette, Andrew Chen, Fabrice Le Boeuf, Fanny Tzelepis, John C. Bell, Debbie D. Crans, and Jean-Simon Diallo. Molecular Therapy, 2018, 26 (1), pp 56-69.
192. “Confinement Effects of Chemical Equilibira: Pentacyano(Pyrazine)Ferrate(II) Stability Changes within Nanosized Droplets of Water” Teofilo Borunda, Alexander J. Meyers, Mary J. Fisher, Debbie C. Crans, and Michael D. Johnson. Molecules, 2018, 23 (4), pp 858-872.
191. “Speciation of metal drugs, supplements and toxins and bodily fluid controls in vitro” Aviva Levina, Debbie C. Crans, Peter A. Lay. Coord. Chem. Rev., 2017, 352, pp 473-498.
190. “Does anion-cation organization in Na+containing X-ray crystal structures relate to solution interactions in inhomogeneous nanoscale environments: Sodium-decavanadate in solid state materials, minerals, and microemulsions” Debbie C. Crans, Benjamin J. Peters, Xiao Wu, and Craig C. McLaughlan. Coord. Chem Rev., 2017, 344, pp 115-130.
189. “Selenium speciation in the Fountain Creek Watershedand its effects on fish diversity” James S. Carsella, Igor Melnykov, Sandra J. Bonetti, Irma Sánchez-Lombardo, and Debbie C. Crans. J. Biol. Inorg. Chem., 2017, 22 (5), pp 751-763.
188. “Selenium Speciation in the Fountain Creek Watershed (Colorado, USA) Correlates with Water Hardness, Ca and Mg Levels” James S. Carsella, Irma Sánchez-Lombardo, Sandra J. Bonetti, and Debbie C. Crans. Molecules, 2017, 22 (5), pp 708.
187. “Selective speciation improves efficacy and lowers toxicity of platinum anticancer and vanadium antidiabetic drugs” Kaitlin A. Doucette, Kelly N. Hassell, and Debbie C. Crans. J. Inorg. Biochem., 2016, 165, pp 56-70.
186. “Differences in Interactions of Benzoic Acid and Benzoate with Interfaces” Benjamin J. Peters, Allison S. Groninger, Fabio L. Fontes, Dean C. Crick, and Debbie C. Crans. Langmuir, 2016, 32 (37), pp 9451-9459.
185. “Multinuclear NMR studies of aqueous Vanadium-HEDTA Complexes” Xiao Wu, Benjamin J. Peters, Christopher D. Rithner and Debbie C. Crans. Polyhedron, 2016, 114, pp 325-332.
184. “How Interfaces Affect the Acidity for the Anilinium Ion” Jarukorn Sripradite, Susanne Miller, Michael D. Johnson, Anan Tongraar, and Debbie C. Crans. Chem. Eur. J., 2016, 22, pp 3873-3880.
183. “Size and shape trump charge in interactions of oxovanadates with self-assembled interfaces: Application of Continuous Shape Measure analysis to the decavanadate anion” Irma Sánchez-Lombardo, Bharat Baruah, Santiago Alvarez, Katarina R. Werst, Nicole A. Segaline, Nancy E. Levinger and Debbie C. Crans. New J. Chem., 2016, 40, pp 962-975.
182. “Antidiabetic, chemical and physical properties of organic vanadates as presumed transition state inhibitors for phosphatases” Debbie C. Crans. J. Org. Chem. 2015, 80 (24), pp 11899-11915. http://dx.doi.org/10.1021/acs.joc.5b02229. This article was featured on the cover.
181. “MenI, a novel menaquinone reductase in Mycobacterium tuberculosis is required for survival in macrophages,” Ashutosh Upadhyay, Fabio Fontes, Mercedes Gonzalez-Juarrero, Michael R. McNeil, Debbie C. Crans, Mary Jackson, and Dean C. Crick. ACS Central Science, 2015, 1, pp 292-302.
180. “Vanadium-protein complexes: Phosphatase inhibitors favor the trigonal bipyramidal transition state geometries,” Craig C. McLauchlan, Benjamin J. Peters, Gail R. Willsky, and Debbie C. Crans. Coord. Chem. Rev., 2015, 301-302, pp 163-199. The article is featured on the Cover.
179. “High-frequency and -field electron paramagnetic resonance of vanadium(IV, III, and II) complexes,” Jurek Krzystek, Andrew Ozarowski, Joshua Telser, and Debbie C. Crans. Coord. Chem. Rev., 2015, 301-302, pp 123-133.
178. “Evaluating transition state structures of vanadium-phosphatase protein complexes using shape analysis,” Irma Sanchez-Lombardo, Santiago Alvarez, Craig C. McLauchlan, and Debbie C. Crans. J. Inorg. Biochem. 2015, 147, pp 153-164.
177. “NMR crystallography for structural characterization of oxovanadium(V) complexes: Deriving coordination geometry and detecting weakly coordinated ligands at atomic resolution in the solid state,” Mingyue Li, Jenna Yehl, Guangjin Hou, Pabitra B. Chatterjee, Amir Goldbourt, Debbie C. Crans, and Tatyana Polenova. Inorg. Chem., 2015, 54, pp 1363-1374.
176. “Novel insights into the mechanism of inhibition of MmpL3, a target of multiple pharmacophores in Mycobacterium tuberculosis,” Wei Li, Ashutosh Upadhyay, Fabio L. Fontes, E. Jeffrey North, Yuehong Wang, Debbie C. Crans, Anna E. Grzegorzewicz, Victoria Jones, Scott G. Franzblau, Richard E. Lee, Dean C. Crick, and Mary Jackson, Antimicrob. Agents Chemotheraphy. 2014, 58 (11), pp 6413-6423.
175. “Electron transfer rate enhancements in nanosized waterpools,” Bret B. Lorenz, Debbie C. Crans, and Michael D. Johnson. Eur. J. Inorg. Chem., 2014, 27, pp 4537-4540.
174. “Trigonal bipyramidal or square pyramidal coordination geometry? Phosphatase inhibiting vanadium compounds,” Debbie C. Crans, Craig C. McLauchlan, and Michael L. Tarlton. Eur. J. Inorg. Chem., 2014, 27, pp 4450-4468.
173. “Spectroscopic characterization of L-ascorbic acid-induced reduction of vanadium(V) dipicolinates: Forming V(III) and V(IV) complexes from V(V) dipicolinate derivatives,” Dorothy C. Horton, Don VanDerveer, J. Krzystek, Joshua Telser, Thomas Pittman, Debbie C. Crans, and Alvin A. Holder. Inorg. Chem. Acta., 2014, 420, pp 112-119.
172. “Guanylurea metformium double salt of decavanadate, (HGU+)4(HMet+)2(V10O286-)·2H2O,” Aungkana Chatkon, Alexa Barres, Nuttaporn Samart, Sarah Boyle, Kenneth J. Haller, and Debbie C. Crans. Inorg. Chem. Acta., 2014, 420, pp 85-91.
171. “Interaction of a biguanide compound with membrane model interface systems; Probing properties of antimalaria and antidiabetic compounds” Nuttaporn Samart, Cheryle N. Beuning, Kenneth Haller, Christopher D. Rithner, and Debbie C. Crans. Langmuir, 2014, 30, pp 8697-8706.
170. “Effects of vanadium (III, IV, V)-chlorodipicolinate on glycolysis and antioxidant status in the liver of STZ-induced diabetic rats,” Mingxia Xie, Deliang Chen, Fang Zhang, Gail R. Willsky, Debbie C. Crans, and Wenjun Ding. J. Inorg. Biochem., 2014, 136, pp 47–56.
169. “Correlation of insulin enhancing properties of vanadium dipicolinate complexes in model membrane systems: Phospholipid langmuir monolayers and AOT reverse micelles,” Audra G. Sostarecz, Ernestas Gaidamauskas, Steve Distin, Sandra J. Bonetti, Nancy E. Levinger, and Debbie C. Crans. Chem. Eur. J., 2014, 20, pp 5149-5159.
168. “Interaction of decavanadate with interfaces and biological model membrane systems: Characterization of soft oxometalate systems,” Nuttaporn Samart, Jessica Saeger, Kenneth J. Haller, Manuel Aureliano, and Debbie C. Crans. J. Mol. Eng. Mat., 2014, 2, pp 1-21.
167. “The active form of anti-diabetic vanadium compounds in the organism,” Yutaka Yoshikawa, Hiromu Sakurai, Debbie C. Crans, Giovanni Micera, and Eugenio Garribba. Dalton Transactions, 2014, 43, pp 6965-6972.
166. “Effect of ancillary ligand on electronic structure as probed by 51V solid-state NMR spectroscopy for vanadium-o-dioxolene complexes,” Olga Goncharov-Zapata, Pabitra B. Chatterjee, Guangjin Hou, Laurence L. Quinn, Mingyue Li, Jenna Yehl, Debbie C. Crans, and Tatyana Polenova. CrystEngComm, 2013, 15, pp 8776-8783.
165. “Metal speciation in health and medicine represented by iron and vanadium,” Debbie C. Crans, Kellie A. Woll, Kestutis Prusinskas, Michael D. Johnson, and Eugenijjus Norkus. Inorg. Chem., 2013, 52, pp 12264-12275. (IC Forum dx.doi.org/10.1021/ic4007873)
164. “Coordination chemistry may explain pharmacokinetics and clinical response of vanadyl sulfate in type 2 diabetic patients,” Gail R. Willsky, Katherine Halvorson, Michael E. Godzala III, Lai-Har Chi, Mathew Most, Peter Kaszynski, Debbie C. Crans, Allison B. Goldfine and Paul J. Kostnyniak. Metallomics, 2013, 5 (11), pp 1491-1502.
163. “Cation exchange, solvent free synthesis and packing patterns of quinolinium nickel(II) dipicolinates,” Babulal Das, Debbie C. Crans and Jubaraj B. Baruah. Inorg. Chim. Acta., 2013, 408, pp 204-208.
162. “Using real time RT-PCR analysis to determine gene expression patterns in RBL-2H3 cells in response to insulin, glucose and the anti-diabetic bis(maltolato)oxovanadium(IV),” Abeer Al-Qatati, Amber L. Wolf-Ringwall, Gerrit J. Bouma, Debbie C. Crans, B. George Barisas and Deborah A. Roess. J. Al Azhar University-Gaza (Natural Sciences), 2013, 15, pp 129-152.
161. “Raft localization of Type1 Fcε receptor and degranulation of RBL-2H3 cells exposed to decavanadate, a structural model for V2O5,” Abeer Al-Qatati, Fabio L. Fontes, B. George Barisas, Dongmei Zhang, Deborah A. Roess and Debbie C. Crans. Dalton Transactions, 2013, 2 (33), pp 11912 – 11920.
160. “Counterion affects interaction with interfaces: The antidiabetic drugs metformin and decavanadate,” Aungkana Chatkon, Pabitra B. Chatterjee, Myles A Sedgwick, Kenneth J. Haller and Debbie C. Crans. Eur. J. Inorg. Chem., 2013, 10-11, pp 1859-1868.
159. “Stabilization of a vanadium(V)-catechol complex by compartmentalization and reduced solvation inside reverse micelles,” Brant G. Lemons, David Richens, Michael D. Johnson, Ashley Anderson, Myles A Sedgwick, and Debbie C. Crans. New J. Chem., 2013, 37, pp 75-81. (Hot topic issue. Cover Manuscript.)
158. “Correlating Proton Transfer Dynamics to Probe Location in Confined Environments,” Myles Sedgwick, Richard L. Cole, Christopher D. Rithner, Debbie C. Crans and Nancy E. Levinger. J. Amer. Chem. Soc., 2012, 134, pp 11904-11907.
157. “Solid-to-solid oxidation of a vanadium(IV) to be a vanadium(V) compound: Chemistry of a sulfur containing siderophore,” Pabitra B. Chatterjee and Debbie C. Crans, Inorg. Chem., 2012, 51, pp 9144-9146.
156. “Redox activity in a vanadium(V) o-dioxolene complex is modulated by protonation state as indicated by 51V solid-state NMR and density functional theory calculations,” Pabitra B. Chatterjee, Olga Goncharov-Zapata, Guangjin Hou, Tatyana Polenova and Debbie C. Crans. Eur. J. Inorg. Chem., 2012, pp 4644-4651.
155. “The conundrum of pH in water nanodroplets: Sensing pH in reverse micelle water pools,” Debbie C. Crans and Nancy E. Levinger. Acc. Chem. Res., 2012, 45, pp 1637-1645.
154. “Insulin and bis(maltolato)oxovanadium(IV) (BMOV) reduce insulin receptor lateral diffusion and increase receptor confinement in membrane microdomains,” Peter W. Winter, Abeer Al-Qatati, Amber Wolf-Ringwall, Samantha Schoeberl, Alan K. Van Orden, B. George Barisas, Deborah A. Roess and Debbie C. Crans. Dalton Transactions, 2012, 41 (21), pp 6419-6430.
153. “Insulin receptors and downstream substrates associate with membrane microdomains after treatment with insulin or chromium(III) picolinate,” Abeer Al-Qatati, Peter W. Winter, Amber L. Wolf-Ringwall, Pabitra B. Chatterjee, Alan K. van Orden, Debbie C. Crans, Deborah A. Roess and B. George Barisas. Cell Biochem. Biophys., 2012, 62 (3), pp 441-450.
152. “Switching off electron transfer reactions in confined media: Reduction of [Co(dipic)2]- and [Co(edta)]- by hexacyanoferrate(II),” Michael D. Johnson, Bret B. Lorenz, Patricia C. Wilkins, Brant G. Lemons, Bharat Baruah, Nathan Lamborn, Michelle Stahla, Pabitra B. Chatterjee, David T. Richens and Debbie C. Crans. Inorg. Chem., 2012, 51 (20), pp 2757-2765.
151. “Quantification of foscarnet with chromogenic and fluorogenic chemosensors: Indicator displacement assays based on metal ion coordination with catechol ligand moiety,” Ernestas Gaidamauskas, Debbie C. Crans, Helen Parker, Kanokkarn Saejueng, Boris A. Kashemirov and Charles E. McKenna. New J. Chem., 2011, 35 (12), pp 2877-2883.
150. “Antidiabetic vanadium compound and membrane interfaces: Interface facilitated metal complex hydrolysis” Debbie C. Crans, Samantha Schoeberl, Ernestas Gaidamauskas, Bharat Baruah and Deborah A. Roess. J. Biol. Inorg. Chem., 2011, 16, pp 961-972.
149. “An AOT-lecithin based gel formulation for intracavitary administration of breast cancer drugs” Kellie A. Woll, Elie J. Schuchardt, Claire R. Willis, Christopher D. Ortengren, Noah Hendricks, Mitch Johnson, Ernestas Gaidamauskas, Bharat Baruah, Audra G. Sostarecz, Deanna R. Worley, David W. Osborne and Debbie C. Crans. Chemistry & Biodiversity, 2011, 8 (12), pp 2195-2210.
148. “Electronic properties of non-innocent compounds probed by solid–state 51V NMR spectroscopy: o-dioxolene vanadium complexes,” Pabitra B. Chatterjee, Olga Goncharov-Zapata, Laurence L. Quinn, Guangjin Hou, Hiyam Hamaed, Robert W. Schurko, Tatyana Polenova, and Debbie C. Crans. Inorg. Chem., 2011, 50, pp 9794-9803. (Contribution invited to the Inorganic Chemistry Forum on Redox Active Ligands)
147. “Layered structure of room temperature ionic liquids in microemulsions by multinuclear NMR spectroscopic studies,” R. Dario Falcone, Bharat Baruah, Ernestas Gaidamauskas, Christopher D. Rithner, N. Mariano Correa, Juana J. Silber, Debbie C. Crans and Nancy E. Levinger, Chem. Eur. J., 2011, 17, pp 6837-6846.
146. “Anti-diabetic effects of a series of vanadium dipicolinate complexes in rats with Streptozotocin induced diabetes,” Gail Ruth Willsky, Lai-Har Chi, Michael E Godzalla, III, Paul J Kostyniak, Jason J Smee, Alejandro M Trujillo, Josephine A Alfano, Wenjin Ding, Zihua Hu and Debbie C. Crans, Coor. Chem. Rev., 2011, 19-20, pp 2258-2269.
145. “How environment affects drug activity: Localization, compartmentalization and reactions of a vanadium insulin-enhancing compound, dipicolinatooxovanadium(V),” Debbie C. Crans, Alejandro M. Trujillo, Philip S. Pharazyn and Mitchell D. Cohen, Coor. Chem. Rev., 2011, 19-20, pp 2178-2192.
144. “Reduced molybenum-oxide-based core–shell hybrids: “Blue” electrons are delocalized on the shell,” Ana Maria Todea, Julia Szakacs, Sanjit Konar, Hartmut Bçgge, Debbie C. Crans, Thorsten Glaser, Helene Rousseliere, Rene Thouvenot, Pierre Gouzerh and Achim Muller, Chem. Eur. J., 2011, 17, pp 6635-6642.
143. “Acidification of reverse micellar nanodroplets by CO2,” Nancy E. Levinger, Lauren C. Rubenstrunk, Bharat Baruah and Debbie C. Crans, J. Am. Chem. Soc., 2011, 133, pp 7205-7213. (Highlighted in Science, 332, (6031), 13 May 2011.)
142. “Coexisting aggregates in mixed Aerosol OT and cholesterol microemulsions,” Myles A. Sedgwick, Alejandro M. Trujillo, Noah Hendricks, Nancy E. Levinger and Debbie C. Crans, Langmuir, 2011, 27 (3), pp 948-954.
141. “Effect of micellar and reverse micellar interface on solute location: 2,6-pyridinedicarboxylate in CTAB micelles and CTAB and AOT reverse micelles,” Ernestas Gaidamauskas, David P. Cleaver, Pabitra B. Chatterjee and Debbie C. Crans, Langmuir, 2010, 26, pp 13153-13161.
140. “Is vanadate reduced by thiols under biological conditions?: Changing the redox potential of V(V)/V(IV) by complexation in aqueous solution” Debbie C. Crans, Boyan Zhang, Ernestas Gaidamauskas, Anastasios D. Keramidas, Gail R. Willsky and Chris R. Roberts, Inorg. Chem., 2010, 49, pp 4245-4256.
139. “Effects of metal compounds with distinct physicochemical properties on iron homeostasis and anti-bacterial activity in the lungs: Cr and V,” Mitchell D. Cohen, Maureen Sisco, Kotaro Yoshida, Lung-chi Chen, Judith T. Zelikoff, Jason Smee, Alvin A. Holder, Jacqueline Stonehuerner, Debbie C. Crans and Andrew J. Ghio, Inhalation Toxicology, 2010, 22 (2), pp 169-178.