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Zheng C, Mattausch H, Simon A. La9Sb16Br3 and Ce9Sb16Cl3: stars and stripes in rare earth halide and intermetallic compounds. Inorg Chem 2005; 44:3684-9. [PMID: 15877452 DOI: 10.1021/ic049220u] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The title compounds were synthesized from Ln, LnX(3) (Ln = La, Ce; X = Cl, Br), and Sb under an Ar atmosphere at 950 degrees C. They crystallize in the space group P6(3)/m (No. 176) with lattice constants a = 21.232(5) and 20.862(2) Angstroms and c = 4.323(2) and 4.2728(7) Angstroms for La(9)Sb(16)Br(3) and Ce(9)Sb(16)Cl(3), respectively. The solids are the most metal-rich members in the reduced rare earth metal halide family and contain partial structures which are characteristic of reduced halides and intermetallic phases. These are the [Ln(6)X(6)](infinity) hexagon stars, Sb-centered [Ln(3)Sb](infinity) trigonal prismatic columns, and stripes of Sb square meshes. Computational analysis indicates that their electronic structure is valence-precise in the reduced halide part, but electron-deficient in the intermetallic part. Susceptibility and resistivity measurements reveal the metallic nature of the compounds.
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352
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Li S, Zheng C, Mattausch H, Simon A. Crystal structure of decacerium pentagallium tetrabromide, Ce10Ga5Br4. Z KRIST-NEW CRYST ST 2005. [DOI: 10.1524/ncrs.2005.220.14.551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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353
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Zheng C, Mattausch H, Simon A.. Crystal structure of tricerium monogallium tribromide,Ce3GaBr3. Z KRIST-NEW CRYST ST 2005. [DOI: 10.1524/ncrs.2005.220.14.334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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354
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Tomlinson S, Zheng C, Hosmane NS, Yang J, Wang Y, Zhang H, Gray TG, Demissie T, Maguire JA, Baumann F, Klein A, Sarkar B, Kaim W, Lipscomb WN. Chemistry of C-Trimethylsilyl-Substituted Heterocarboranes. 31. New Insights into Reaction Pathways of Carborane Ligand Systems: Synthetic, Structural, Spectroscopic, and Electrochemical Studies on Sandwich and Half-Sandwich Metallacarboranes of Iron, Cobalt, and Nickel. Organometallics 2005. [DOI: 10.1021/om048982u] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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355
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Gu Y, Zheng C, Zhao Y, Ke H, Fan H. A new iterative procedure for combining direct methods with solvent flattening - dealing with the phase ambiguity in protein crystallography. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2005; 53:792-4. [PMID: 15299873 DOI: 10.1107/s090744499700680x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A new procedure for combining direct methods with the solvent-flattening technique is proposed for phasing single isomorphous replacement (SIR) or one-wavelength anomalous scattering (OAS) data of proteins. The new procedure differs from the previous one [Zheng, Zheng, Gu, Mo, Fan & Hao (1997). Acta Cryst. D53, 49-55] in that the direct method not only provides input phases to but also accepts feedback phases from solvent flattening, thus forming an iterative process for breaking the ambiguities and refining the values of phases. The new procedure was tested with the experimental SIR data of the known structure ribonuclease Sa. For the strongest 1000 of the total 7264 reflections, the mean F(obs)-weighted phase error is 7.5 and 9.4 degrees lower than that of the previous procedure and that of solvent flattening alone, respectively.
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356
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Wu CK, Rose JP, Zheng C, Breslow E, Wang BC. Crystals of ligand-free bovine neurophysin II. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2005; 52:946-9. [PMID: 15299603 DOI: 10.1107/s0907444996005513] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A modified neurophysin, des 1-6 bovine neurophysin II, has been crystallized in the absence of bound hormone or hormone analogue. These crystals represent the first crystals of ligand-free neurophysin, and are essential for understanding neurophysin-hormone recognition as well as hormone-induced neurophysin dimerization. The crystals diffract to beyond 1.8 A resolution, belong to space group P3(1)21 (or P3(2)21) with a = 48.86, c = 78.61 A, and contain one molecule per asymmetric unit.
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357
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Mattausch H, Zheng C, Ryazanov M, Simon A. Reduced Lanthanum Halides with Ge as Interstitials: La2I2Ge, La2I2Ge2, La3Cl2Ge3, La3Br2Ge3, La3I3Ge, La6I5Ge3 and La7+xI12Ge. Z Anorg Allg Chem 2005. [DOI: 10.1002/zaac.200400269] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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358
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Zheng C, Mattausch H, Li S. Fused Stars and Nano-Stripes in the Rare Earth Halide La7Sb11Br4. Z Anorg Allg Chem 2005. [DOI: 10.1002/zaac.200400306] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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359
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Liu X, Goodfellow MR, Yu Q, Zheng C. Correlation of ph dependant equilibrium isotherms of heavy metal biosorption with a modified Freundlich model. ENVIRONMENTAL TECHNOLOGY 2004; 25:1341-8. [PMID: 15691194 DOI: 10.1080/09593332508618469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Equilibrium isotherms of heavy metal biosorption are commonly correlated with adsorption models such as the Freundlich model. On the other hand, the adsorption properties of heavy metal biosorption are strongly influenced by the solution pH of the biosorption system. Therefore, standard adsorption models are limited to the correlation of equilibrium isotherms under constant pH values. In this paper, a modified Freundlich model was developed for the correlation of pH dependent equilibrium isotherms of heavy metal biosorption. The model was based on the mechanism that the functional groups for heavy metal interactions are weakly acidic groups and the uptake capacities of the biomass are affected through the association and dissociation equilibrium between two apparent ionic forms. Both the standard and the modified Freundlich models were tested with isotherm data for Cd2+, Cu2+ and Ni2+ biosorption onto pre-treated biomass of marine alga Durvillaea potatorum under various solution pH values. Regression analyses indicated that the developed model correlated the experimental data well.
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Mattausch H, Zheng C, Kienle L, Simon A. The First Reduced Rare Earth Halide with a Group 11 Element as Interstitial: La3I3Au. Z Anorg Allg Chem 2004. [DOI: 10.1002/zaac.200400322] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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361
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Wang J, Zheng C, Li A, Allard CL, Smith JL, Arikatla G, Maguire JA, Hosmane NS. Half-sandwich halolanthanacarboranes of the “carbons adjacent” C2B4-carborane ligand systems: important synthons for new polyhedral cage constructs. INORG CHEM COMMUN 2004. [DOI: 10.1016/j.inoche.2004.07.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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362
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Wang J, Li S, Zheng C, Li A, Hosmane NS, Maguire JA, Roesky HW, Cummins CC, Kaim W. Chemistry of C-Trimethylsilyl-Substituted Heterocarboranes. 30. Synthetic and Structural Studies on Oxide Ion Encapsulating Tetralanthanide Tetrahedra Surrounded by “Carbons Apart” C2B4-Carborane Ligands (Ln(III) = La, Nd, Gd, Tb, Ho, Lu). Organometallics 2004. [DOI: 10.1021/om0496176] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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363
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Yao Q, Kinney EP, Zheng C. Selenium-Ligated Palladium(II) Complexes as Highly Active Catalysts for Carbon−Carbon Coupling Reactions: The Heck Reaction. Org Lett 2004; 6:2997-9. [PMID: 15330667 DOI: 10.1021/ol0486977] [Citation(s) in RCA: 176] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Three selenium-ligated Pd(II) complexes were readily synthesized and shown to be extremely active catalysts for the Heck reaction of various aryl bromides, including deactivated and heterocyclic ones. The catalytic activity of the selenide-based Pd(II) complexes not only rivals but vastly outperforms that of the corresponding phosphorus and sulfur analogues. Practical advantages of the selenium-based catalysts include their straightforward synthesis and high activity in the absence of any additives as well as the enhanced stability of the selenide ligands toward air oxidation.
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364
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Mattausch H, Simon A, Zheng C. Crystal structure of pentalanthanum trilead monoiodide, La5Pb3I. Z KRIST-NEW CRYST ST 2004. [DOI: 10.1524/ncrs.2004.219.2.87] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Abstract ILa5Pb3, hexagonal, P63/mcm (no. 193), a = 9.736(1) Å, c = 6.947(1) Å, V = 570.3 Å3, Z = 2, Rgt(F) = 0.029, wRref(F2) = 0.068, T = 293 K.
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365
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Li A, Wang J, Zheng C, Maguire JA, Hosmane NS. Novel Sandwich Complexes of Terbium and Erbium Metals Derived from Mixed η5 Open-Pentadienyl and C2B4 Carborane Ligands: A Synthetic and Structural Investigation. Organometallics 2004. [DOI: 10.1021/om0497341] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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366
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Mattausch H, Oeckler O, Zheng C, Simon A. Die Verbindung La5Br4Al4 und ihre topologische Verwandtschaft mit dem Ln3ClGa4-Typ. Z Anorg Allg Chem 2004. [DOI: 10.1002/zaac.200300395] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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367
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Wang J, Li S, Zheng C, Hosmane NS, Maguire JA, Roesky HW, Cummins CC, Kaim W. An Oxide Ion Encapsulating Tetraholmium Tetrahedron Stabilized by Complexation with the “Carbons Apart” C 2B 4-Carborane Ligands. Organometallics 2004. [DOI: 10.1021/om040048b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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368
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Mattausch H, Simon A, Zheng C. Crystal structure of trilanthanum monolead triiodide, La3Pbl3. Z KRIST-NEW CRYST ST 2004. [DOI: 10.1524/ncrs.2004.219.14.378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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369
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Mattausch H, Simon A, Zheng C. Crystal structure of pentalanthanum trilead monoiodide, La5Pb3l. Z KRIST-NEW CRYST ST 2004. [DOI: 10.1524/ncrs.2004.219.14.97] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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370
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Zhang MZ, Fu ZF, Liu XR, Zheng C. [A comparison study of pulsitile ocular blood flow in normal eyes and primary open angle glaucoma]. [ZHONGHUA YAN KE ZA ZHI] CHINESE JOURNAL OF OPHTHALMOLOGY 2004; 40:250-3. [PMID: 15268833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/30/2023]
Abstract
OBJECTIVE To compare pulsatile ocular blood flow (POBF) and intraocular pressure (IOP) in primary open angle glaucoma (POAG) and normal control group matched for age, sex and refraction error, to investigate the rule of hem-dynamics in POAG and to determine the sensitivity and specificity of POBF measurement as a diagnostic test for glaucoma. METHODS Prior to the test a questionnaire was completed to determine age, sex, refractive error, family history of glaucoma, history of eye diseases, ocular medication, medical history and using of systemic beta-blockers. Patients of POAG were determined by following diagnostics standards: (1) Three IOP >25 mm Hg in different times of one day. (2) The fluctuate of IOP > 8 mm Hg during 24 hours. (3) Typical glaucoma changes in the visual field. (4) Typical glaucoma changes in optic disc. There were 100 POAG subjects with single eye observed (50 male and 50 female). We picked up 100 eyes randomly (50 male and 50 female) in 534 normal persons who matched for following conditions: (1) Sex. (2) Discrepancy of age less than 5 years. (3) Discrepancy of the refraction error less than +/- 2.00 DS. as the normal comparison group. The tonometer used was the POBF Tonometry. Pulse amplitude of IOP (PA), pulsatile ocular blood flow (POBF), pulse/heart rate (PR), maximum-IOP (max-IOP), minimum-IOP (min-IOP) and average IOP (aver-IOP) were obtained before the medical therapy and 1 or 2 weeks after the operation. The correlation between the POBF & mean value of the perimeter was analyzed. POBF was analyzed to determine the sensitivity and specificity of POBF measurement as a diagnostic test. RESULTS The value of POBF in POAG and normal control was (9.72 +/- 3.47) microl/s and (12.04 +/- 4.68) microl/s, respectively. POAG patients' POBF, PV, PA, and AVE-IOP were less than those in the normal control, and the difference was statistically significant. There was no statistically significant correlation between the changes of visual field and POBF (r = 0.224, P = 0.219). The sensitivity and specificity of using the POBF for diagnosis of POAG (less than 10.75 microl/s being abnormal) were 0.422 and 0.623, respectively. CONCLUSION Abnormal of vas-autoregulation and blood supply play a role in the pathogenesis of POA. Due to the lower sensitivity and specificity, it is not suitable to use POBF as a diagnostic test to distinguish the POAG and normal. But the POBF reflects the change of blood flow in a pulsing cycle and provide more information than the measurement of IOP only.
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371
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Wang J, Voutetakis A, Zheng C, Baum BJ. Rapamycin control of exocrine protein levels in saliva after adenoviral vector-mediated gene transfer. Gene Ther 2004; 11:729-33. [PMID: 14737095 DOI: 10.1038/sj.gt.3302225] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Transgene-encoded therapeutic secretory proteins can be efficiently secreted from salivary glands into saliva or the bloodstream after adenoviral (Ad)-mediated gene transfer. Since transgene expression from conventional vectors is typically unregulated, we evaluated the rapamycin-based dimerizer regulation system for control of transgene expression in, and consequent exocrine protein secreted from, rat salivary glands. We used human growth hormone (hGH) as a surrogate exocrine secretory protein. Two Ad vectors, Ad C4ZF3, encoding activation and DNA binding domain fusion polypeptides, and Ad Z12-I-GH-2, encoding hGH, were constructed and shown useful in vitro. Thereafter, both vectors were delivered into submandibular glands by retroductal infusion. After 24 h, rapamycin (0, 1, 3 or 10 mg/kg) was administered, and 20 h later hGH levels in saliva were determined. Salivary hGH levels were rapamycin concentration dependent. At a rapamycin dose of 10 mg/kg, total salivary hGH was 693+/-197 ng and the hGH concentration in saliva was 4.6+/-1.3 microg/ml. Over a 16-day experimental period, three separate administrations of rapamycin (3 mg/kg) induced distinct elevations of salivary hGH (approximately 100-200 ng total hGH) that were entirely rapamycin dependent. This study demonstrates for the first time pharmacological control of transgenic exocrine protein production and presence in saliva after salivary gland gene transfer, and the potential for its application to the management of oral, oropharyngeal and upper gastrointestinal tract disorders.
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372
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Yang J, Zheng C, Maguire JA, Hosmane NS. Small cage d10 metallacarboranes: crystal structure of the mercury bridged carborane, μ,μ′-[2-(Si(CH3)3)-3-(CH3)-2,3-C2B4H5]2Hg. INORG CHEM COMMUN 2004. [DOI: 10.1016/j.inoche.2003.10.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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373
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Li SJ, Zheng C, Lobringn KC. Refinement of the crystal structure of gallium oxide hydroxide, GaO(OH). Z KRIST-NEW CRYST ST 2003. [DOI: 10.1524/ncrs.2003.218.jg.11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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374
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Wang J, Zheng C, Maguire JA, Hosmane NS. A New Class of Constrained-Geometry Metallocenes: Synthesis and Crystal Structure of a Carboranyl−Thiol-Appended Half-Sandwich Titanocene and Its Conversion to Halotitanocene. Organometallics 2003. [DOI: 10.1021/om0340802] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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375
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Wang J, Li S, Zheng C, Hosmane NS, Maguire JA, Roesky HW, Cummins CC, Kaim W. An Oxide Ion Encapsulating Tetraholmium Tetrahedron Stabilized by Complexation with the “Carbons Apart” C2B4-Carborane Ligands. Organometallics 2003. [DOI: 10.1021/om034019x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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376
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Wang J, Li S, Zheng C, Maguire JA, Sarkar B, Kaim W, Hosmane NS. Chemistry of C-Trimethylsilyl-Substituted Heterocarboranes. 29. Synthetic and Structural Studies on Lanthanacarboranes with Two and Three “Carbons Apart” Carborane Cages Bonding to Ln(III) Metal (Ln(III) = Nd, Gd, Dy, Ho, Er, Tb, Lu). Organometallics 2003. [DOI: 10.1021/om030426x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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377
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Wang J, Zhu Y, Li S, Zheng C, Maguire JA, Hosmane NS. Group 4 metallacarboranes of constrained geometries derived from B(cage)- and C(cage)-silylamido-substituted carborane ligands: a synthetic and structural investigation. J Organomet Chem 2003. [DOI: 10.1016/s0022-328x(03)00317-6] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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378
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Mandal SK, Nagana Gowda G, Krishnamurthy SS, Zheng C, Li S, Hosmane NS. Diastereomerism in palladium(II) allyl complexes of P,P-, P,S- and S,S-donor ligands, Ph2P(E)N(R)P(E′)Ph2 [R=CHMe2 or (S)-*CHMePh; E=E′=lone pair or S]: solution behaviour, X-ray crystal structure and catalytic allylic alkylation reactions. J Organomet Chem 2003. [DOI: 10.1016/s0022-328x(03)00227-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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379
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Zheng C, Mattausch H, Oeckler O, Simon A. Ce10Cl4Ga5 and Ln3ClGa4 (Ln = La, Ce): reduced halides or oxidized intermetallics? Inorg Chem 2003; 42:3130-5. [PMID: 12716212 DOI: 10.1021/ic026086+] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The compounds Ce(10)Cl(4)Ga(5) and Ln(3)ClGa(4) (Ln = La, Ce) were synthesized from stoichiometric mixtures of Ln, LnCl(3), and Ga under Ar atmosphere in sealed Ta ampules at 910-1020 degrees C for 25-26 days. Ce(10)Cl(4)Ga(5) is isostructural to La(10)Cl(4)Ga(5) (space group I4/mcm, No. 140) with lattice constants a = 7.9546(11) A, c = 31.793(6) A. Ln(3)ClGa(4) represents a new structural type, also in the space group I4/mcm, with a = 8.1955(8) and 8.1123(11) A, c = 11.363(2) and 11.229(2) A, respectively, for Ln = La and Ce. Ce(10)Cl(4)Ga(5) features building blocks of Ga-centered Ce(6) trigonal prisms and distinctive two-dimensional intermetallic CuAl(2) and U(3)Si(2) type nets. Its electronic structure falls within the realm of reduced rare-earth halides. Ln(3)ClGa(4) also contains the intermetallic CuAl(2) type nets, but the interstitials are inverted: The building blocks are Cl-centered Ln(6) octahedra. Its electronic structure is characterized by strong peripheral Ln-Ga bonding stabilizing the Ln(6)Cl octahedron which normally would have its Ln-Ln antibonding orbitals filled with electrons from interstitials beyond chalcogen. Magnetic susceptibility and conductivity measurements confirm the metallic nature of all three compounds.
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Wang J, Li S, Zheng C, Maguire JA, Hosmane NS. Metallacarboranes as an anion and a cation in a single species: a unique example for ion pairs. INORG CHEM COMMUN 2003. [DOI: 10.1016/s1387-7003(03)00039-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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381
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Pan L, Adams KM, Hernandez HE, Wang X, Zheng C, Hattori Y, Kaneko K. Porous lanthanide-organic frameworks: synthesis, characterization, and unprecedented gas adsorption properties. J Am Chem Soc 2003; 125:3062-7. [PMID: 12617673 DOI: 10.1021/ja028996w] [Citation(s) in RCA: 575] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The reactions of Ln(NO(3))(3) (Ln = La, Er) with 1,4-phenylendiacetic acid (H(2)PDA) under hydrothermal conditions produce isostructural lanthanide coordination polymers with the empirical formula [Ln(2)(PDA)(3)(H(2)O)] x 2H(2)O. The extended structure of [Ln(2)(PDA)(3)(H(2)O)] x 2H(2)O consists of Ln-COO triple helices cross-linked through the [bond]CH(2)C(6)H(4)CH(2)[bond] spacers of the PDA anions, showing 1D open channels along the crystallographic c axis that accommodate the guest and coordinated water molecules. Evacuation of [Er(2)(PDA)(3)(H(2)O)] x 2H(2)O at room temperature and at 200 degrees C, respectively, generates [Er(2)(PDA)(3)(H(2)O)] and [Er(2)(PDA)(3)], both of which give powder X-ray diffraction patterns consistent with that of [Er(2)(PDA)(3)(H(2)O)] x 2H(2)O. The porosity of [Er(2)(PDA)(3)(H(2)O)] and [Er(2)(PDA)(3)] is further demonstrated by their ability to adsorb water vapor to form [Er(2)(PDA)(3)(H(2)O)] x 2H(2)O quantitatively. Thermogravimetric analyses show that [Er(2)(PDA)(3)] remains stable up to 450 degrees C. The effective pore window size in [Er(2)(PDA)(3)] is estimated at 3.4 A. Gas adsorption measurements indicate that [Er(2)(PDA)(3)] adsorbs CO(2) into its pores and shows nonporous behavior toward Ar or N(2). There is a general correlation between the pore size and the kinetic diameters of the adsorbates (CO(2) = 3.3 A, Ar = 3.40 A, and N(2) = 3.64 A). That the adsorption favors CO(2) over Ar is unprecedented and may arise from the combined differentiations on size and on host-guest interactions.
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382
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Prommer H, Barry DA, Zheng C. MODFLOW/MT3DMS-based reactive multicomponent transport modeling. GROUND WATER 2003; 41:247-257. [PMID: 12656291 DOI: 10.1111/j.1745-6584.2003.tb02588.x] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
This paper presents a three-dimensional, MODFLOW/MT3DMS-based reactive multicomponent transport model for saturated porous media. Based on a split-operator technique, the model, referred to as PHT3D, couples the transport simulator MT3DMS and the geochemical modeling code PHREEQC-2. Through the flexible, generic nature of PHREEQC-2, PHT3D can handle a broad range of equilibrium and kinetically controlled reactive processes, including aqueous complexation, mineral precipitation/dissolution, and ion exchange. The diversity of potential applications is demonstrated through simulation of five existing literature benchmarks and a new three-dimensional sample problem. The model might be applied to simulate the geochemical evolution of pristine and contaminated aquifers as well as their cleanup. The latter problem class includes the natural and enhanced attenuation/remediation schemes of a wide range of organic and inorganic contaminants. Processes/reactions not included in the standard PHREEQC-2 database but typical for this type of application (e.g., NAPL dissolution, microbial growth/decay) can be defined and included via the extensible PHREEQC-2 database file.
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383
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Li SJ, Zheng C, Lobring KC. Refinement of the crystal structure of gallium oxide hydroxide, GaO(OH). Z KRIST-NEW CRYST ST 2003. [DOI: 10.1524/ncrs.2003.218.1.11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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384
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Bujici TM, Wang XT, Li SJ, Zheng C. Crystal structure of Co(II)/Zn(II) coordination polymers supported by 1,3-bis(4-pyridyl)propane, {[Co(ClO4)2(C13H14N2)2] · 2C6H6}n and {[Zn(ClO4)2(C13H14N2)2] · 2C6H6}n. Z KRIST-NEW CRYST ST 2003. [DOI: 10.1524/ncrs.2003.218.1.148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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385
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Yang X, Brown AL, Furukawa M, Li S, Gardinier WE, Bukowski EJ, Bright FV, Zheng C, Zeng XC, Gong B. A new strategy for folding oligo(m-phenylene ethynylenes). Chem Commun (Camb) 2003:56-7. [PMID: 12610963 DOI: 10.1039/b209809a] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Backbone-rigidified oligo(m-phenylene ethynylenes) fold into crescent or helical conformations in non-polar organic solvents.
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386
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Liu X, Wang X, Zhao Y, Zheng C, Zhou G. Complete nucleotide sequence of a potyvirus causing maize dwarf mosaic disease in central China. Acta Virol 2003; 47:223-7. [PMID: 15068377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
The full-length nucleotide sequence of a potyvirus causing the maize dwarf mosaic (MDM) disease in Henan province, central China, was obtained by reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of the cDNA 5'-end (5'-RACE). The viral genome comprised of 9596 nucleotides except the polyA tail and encoded a putative polyprotein of 3603 amino acids. The entire genomic sequence of this isolate shared identities of 94.2% and 98.3% with Sugarcane mosaic virus (SCMV) HZ isolate at the nucleotide and deduced amino acid levels, respectively, but only a 69.1% identity with MDM virus (MDMV) Bulgarian isolate (MDMV-Bg) at the nucleotide level. Phylogenetical tree analysis of the complete nucleotide sequences indicated that the Henan isolate of a potyvirus causing MDM disease is in fact a Henan strain of SCMV (SCMV-HN).
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387
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Zheng C, Mattausch H, Oeckler O, Nuss J, Simon A. La4Br2Al5 and Ce4Br2Ga5: Three-dimensional Metal Networks Embedded in Condensed Ln6 Trigonal Prisms. Z Anorg Allg Chem 2003. [DOI: 10.1002/zaac.200300214] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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388
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Zheng C, Lin J. [The role of L-arginine and L-citrulline in activated macrophage against Toxoplasma gondii infection in vitro]. ZHONGGUO JI SHENG CHONG XUE YU JI SHENG CHONG BING ZA ZHI = CHINESE JOURNAL OF PARASITOLOGY & PARASITIC DISEASES 2002; 16:326-30. [PMID: 12078267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
AIM To determine whether both the production of NO and the toxoplasmastatic or toxoplasmacidal activity of activated macrophages cultured in physiologic levels of arginine can be enhanced by increasing the availability of arginine, or citrulline. METHODS After the activated M phi were infected with the RH strain of T. gondii, the levels of NO production, the infection rate of M phi and the number of tachyzoites in parasitophorous vacuoles were determined after the M phi were cultured in medium added with various concentrations of L-arginine or L-citrulline for 18 h. RESULTS (1) The multiplication of intracellular toxoplasmic tachyzoites could be inhibited by activated macrophages, depending on the production of NO in the presence of physiologic levels of arginine. (2) Increased exogenous arginine or citrulline resulted in a significant elevation of NO production induced by activated macrophages and further reduction of infection rate of macrophages as well as inhibition of multiplication of intracellular tachyzoites. (3) Citrulline could fully substitute for arginine in enhancing NO production and toxoplasmastatic or toxopasmacidal activity. CONCLUSION The physiological levels of arginine were able to induce sufficient intrinsic NO production to inhibit intracellular multiplication of toxoplasmatic tachyzoite but unable to protect cell from infection and that increasing the substrate levels for NO biosynthesis may enhance in vitro toxoplasmastatic or toxoplasmacidal activity of activated macrophages.
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389
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Zheng C, Li S, Mattausch H, Simon A. Crystal structure of pentalanthanum bromotriindate, La5In3Br. Z KRIST-NEW CRYST ST 2002. [DOI: 10.1524/ncrs.2002.217.1.321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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390
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Zheng C, Li S, Mattausch H, Simon A. Crystal structure of pentalanthanum bromotriindate, La5In3Br. Z KRIST-NEW CRYST ST 2002. [DOI: 10.1524/ncrs.2002.217.jg.321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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391
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Wang J, Li S, Zheng C, Maguire JA, Hosmane NS. Synthesis and Crystal Structure of a “Carbons Apart” Erbacarborane Sandwich: An Example of Novel, One-Pot, Two-Electron Reductive Cage Opening with Concomitant Metalation of the C2B4 Carborane Ligand. Organometallics 2002. [DOI: 10.1021/om020663k] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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392
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Gorenflo M, Zheng C, Pöge A, Bettendorf M, Werle E, Fiehn W, Ulmer HE. Metabolites of the L-arginine-NO pathway in patients with left-to-right shunt. Clin Lab 2002; 47:441-7. [PMID: 11596905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
OBJECTIVES The endogenous production of metabolites of the L-arginine-NO pathway has been found to be altered in patients with left-to-right shunt and pulmonary hypertension. The objective of this study was to analyze the influence of age and of the magnitude of the left-to-right shunt on plasma levels of L-arginine, cyclic guanosine monophosphate (cGMP), nitrite and nitrate in children and young adults presenting with left-to-right shunt. METHODS Twenty-nine patients with ventricular septal defect (n=18), atrial septal defect (n=6) and atrioventricular canal (n=5) were assigned to group I when the ratio of pulmonary to systemic blood flow (Qp/Qs) was less than 1.5 (n=10) and to group II when Qp/Qs > or = 1.5 (n=19). At cardiac catheterization blood samples were taken from the pulmonary vein or left ventricle. In 33 controls peripheral venous blood was obtained. cGMP levels were determined by radioimmunoassay, L-arginine, nitrite and nitrate by high performance liquid chromatography (HPLC). RESULTS L-arginine plasma levels were lower in group II than in controls (51.7 [23.3-82.2] versus 60.5 [32.4-85.9] pmol/l; p < 0.05 by KRUSKAL-WALLIS). Age did not influence the L-arginine plasma levels (p = 0.30). cGMP levels depended on age (p<0.01) and mean pulmonary artery pressure (p <0.01) but not on high pulmonary blood flow (p=0.85; ANOVA). Plasma nitrite and nitrate were not different in both groups and when compared with controls (nitrite: 26.0 [23.5-31.0] micromol/l; nitrate: 26.8 [24.0-32.0] micromol/l). CONCLUSIONS Age and pulmonary artery pressure exert important effects on plasma cGMP. Measurement of nitrite and nitrate in plasma alone may not reflect the endogenous NO production. Future studies should evaluate the role of plasma levels of L-arginine in patients with high pulmonary blood flow undergoing repair of their defect.
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393
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Gong B, Zeng H, Zhu J, Yuan L, Han Y, Cheng S, Furukawa M, Parra RD, Kovalevsky AY, Mills JL, Skrzypczak-Jankun E, Martinovic S, Smith RD, Zheng C, Szyperski T, Zeng XC, Yua L. Creating nanocavities of tunable sizes: hollow helices. Proc Natl Acad Sci U S A 2002; 99:11583-8. [PMID: 12177422 PMCID: PMC129312 DOI: 10.1073/pnas.162277099] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A general strategy for creating nanocavities with tunable sizes based on the folding of unnatural oligomers is presented. The backbones of these oligomers are rigidified by localized, three-center intramolecular hydrogen bonds, which lead to well-defined hollow helical conformations. Changing the curvature of the oligomer backbone leads to the adjustment of the interior cavity size. Helices with interior cavities of 10 A to >30 A across, the largest thus far formed by the folding of unnatural foldamers, are generated. Cavities of these sizes are usually seen at the tertiary and quaternary structural levels of proteins. The ability to tune molecular dimensions without altering the underlying topology is seen in few natural and unnatural foldamer systems.
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394
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Zheng C, Lei Y, Yu Q, Lui X, Huan K. Enzymatic hydrolysis of waste sugarcane bagasse in water media. ENVIRONMENTAL TECHNOLOGY 2002; 23:1009-1016. [PMID: 12361374 DOI: 10.1080/09593332308618349] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Enzymatic hydrolysis of natural cellulose such as sugarcane bagasse is usually carried out in a buffer medium. In this paper, the enzymatic hydrolysis of a waste sugarcane bagasse in water media was carried out.The bagasse was pre-treated with heating explosion and pure (ion exchange), reverse-osmosis and tap water media were used in place of a buffer solution in the hydrolysis process. The yields for reducing sugars and the changes in solution pH and electric conductivity during the hydrolysis under various conditions were studied. The results were also compared with those obtained in buffer solutions. Similar levels of sugar yields were obtained in water and buffer solution media. The pH of the hydrolyzate was in the range of 4.5 - 5.0, which coincided with the optimum pH for the enzyme reaction. It was considered that the enzyme and the substrate formed a transitional complex in the hydrolysis process. The transitional complex provided the buffering capacity pH 5. The results indicate of the hydrolyzate solution at around that industrialization of the enzymatic hydrolysis in a water medium is feasible.
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395
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Wang J, Li S, Zheng C, Maguire JA, Hosmane NS. Synthesis and crystal structure of the first “carbons apart” diamagnetic lutetiacarborane sandwich complex. INORG CHEM COMMUN 2002. [DOI: 10.1016/s1387-7003(02)00491-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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396
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Mandal S, Nagana Gowda G, Krishnamurthy S, Zheng C, Li S, Hosmane NS. Allylpalladium Complexes of Mixed-Donor Diphosphazane Ligands Bearing a Stereogenic Phosphorus Centre: Structure and Stereodynamics. Eur J Inorg Chem 2002. [DOI: 10.1002/1099-0682(200208)2002:8<2047::aid-ejic2047>3.0.co;2-r] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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397
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Wang J, Li S, Zheng C, Maguire JA, Hosmane NS. Novel Lanthanocene Analogues of “Carbons Apart” Erba- and Dysprosacarboranes: Synthetic and Structural Investigation. Organometallics 2002. [DOI: 10.1021/om020269m] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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398
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Vyakaranam K, Rana G, Spielvogel BF, Mitchell JL, Li S, Zheng C, Hosmane NS. Synthesis and crystal structure of 1,4-diaminobutyl-N,N′-bis(cyanoborane): the first substituted-borane adduct of putrescine. INORG CHEM COMMUN 2002. [DOI: 10.1016/s1387-7003(02)00462-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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399
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Vyakaranam K, Rana G, Li S, Zheng C, Spielvogel BF, Maguire JA, Hosmane NS. Convenient one-pot synthesis of triphenylphosphinecarbomethoxyborane: antitumor activity and structural investigation. INORG CHEM COMMUN 2002. [DOI: 10.1016/s1387-7003(02)00445-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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400
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Zheng C, Hoffmann R, Nelson DR. A helical face-sharing tetrahedron chain from irrational twist, stella quadrangula, and related matters. J Am Chem Soc 2002. [DOI: 10.1021/ja00166a012] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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