51
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Micó XÀ, Richter M, Schwarz S, Strähle J, Ziegler T, Subramanian LR. Crystal structure of nonafluoro-{N-[(E)-2-(2-hydroxyphenyl)diazenyl]- phenyl} -1 -butanesulfonamide, C16H10F9N3O3S. Z KRIST-NEW CRYST ST 2003. [DOI: 10.1524/ncrs.2003.218.jg.581] [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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52
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Ziegler T, Winkler C, Kleine HD, Steiner M. Paroxysmal nocturnal hemoglobinuria in a 63-year-old patient. Clin Lab 2003; 48:365-8. [PMID: 12146569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
Abstract
Intermittently occuring hemolytic anemia can be the expression of paroxysmal nocturnal hemoglobinuria (PNH). Diagnosis is made via the detection of decreased resistance of the erythrocytes to acidified serum or osmotic hemolysis. Furthermore, diagnostic proof is provided by the cytometric detection of several erythrocyte populations caused by the altered expression of an anchor protein (PIG-A protein) of the cell membrane. This report is of a case where "black morning urine" has been in existence for more than 10 years and in which the additional occurrence of icterus led to the diagnosis. The patient's spleen had been removed in 1964 because of idiopathic thrombopenia, in retrospect, however, thrombopenia within the framework of PNH should be considered.
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53
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Ziegler T, Folga E, Berces A. A density functional study on the activation of hydrogen-hydrogen and hydrogen-carbon bonds by Cp2Sc-H and Cp2Sc-CH3. J Am Chem Soc 2002. [DOI: 10.1021/ja00055a037] [Citation(s) in RCA: 136] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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54
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Masters AP, Sorensen TS, Ziegler T. A theoretical study of ketene forming reactions involving halogen abstraction by metal carbonyl anions. Organometallics 2002. [DOI: 10.1021/om00106a033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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55
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Woo TK, Fan L, Ziegler T. Density Functional Study of the Insertion Step in Olefin Polymerization by Metallocene and Constrained-Geometry Catalysts. Organometallics 2002. [DOI: 10.1021/om00014a012] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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56
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Woo TK, Fan L, Ziegler T. A Density Functional Study of Chain Growing and Chain Terminating Steps in Olefin Polymerization by Metallocene and Constrained Geometry Catalysts. Organometallics 2002. [DOI: 10.1021/om00018a019] [Citation(s) in RCA: 207] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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57
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Fan L, Krzywicki A, Somogyvari A, Ziegler T. Density Functional Study of Ethylene Dimerization by (Acetylacetonato)nickel Hydride. Inorg Chem 2002. [DOI: 10.1021/ic00101a021] [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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58
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Gutsev GL, Ziegler T. Theoretical study on neutral and anionic halocarbynes and halocarbenes. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100172a024] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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59
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Folga E, Ziegler T. Density functional study on molybdacyclobutane and its role in olefin metathesis. Organometallics 2002. [DOI: 10.1021/om00026a018] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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60
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Fortier S, Baird MC, Preston KF, Morton JR, Ziegler T, Jaeger TJ, Watkins WC, MacNeil JH, Watson KA. Combined x-ray crystallographic, single-crystal EPR, and theoretical study of metal-centered radicals of the type [.eta.5C5R5Cr(CO)2L] (R = H, Me; L = CO, tertiary phosphine). J Am Chem Soc 2002. [DOI: 10.1021/ja00002a023] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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61
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Pyhälä R, Ziegler T, Lumio J. [Targeted drugs against influenza--how will this affect the epidemics?]. DUODECIM; LAAKETIETEELLINEN AIKAKAUSKIRJA 2002; 116:13-5. [PMID: 11764456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
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62
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Michalak A, Ziegler T. DFT studies on the copolymerization of alpha-olefins with polar monomers: ethylene-methyl acrylate copolymerization catalyzed by a Pd-based diimine catalyst. J Am Chem Soc 2001; 123:12266-78. [PMID: 11734027 DOI: 10.1021/ja010876l] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Gradient-corrected density functional theory has been used to study the elementary reactions for the copolymerization of ethylene with methyl acrylate catalyzed by Pd-based diimine catalysts, modeled by the generic complex N(wedge)N-Pd(n-C(3)H(7))(+), with N(wedge)N = -NHCHCHNH-. The steric effects in the real systems are discussed on the basis of the calculations for the catalyst with N(wedge)N = -NArCRCRNAr-, R = CH(3), and Ar = C(6)H(3)(i-Pr(2)) and the previous calculations on ethylene/propylene polymerization. Considerations have been given to the different possible acrylate complexes, as well as the transition states and the products (agostic complexes and the alternative chelates) for two acrylate insertion paths (1,2 and 2,1). The chelate-opening reactions have also been studied. The results revealed a strong electronic preference for the 2,1-insertion paths, with a barrier that is 4.5 kcal/mol lower than any other studied insertion pathway. In the real systems the 2,1-insertion of acrylate is preferred by 0.5 kcal/mol. The 2,1-insertion barrier calculated for the real system of 12.4 kcal/mol is in very good agreement with the experimental value of 12.1 kcal/mol. The six-member chelate is the most stable insertion product with an energy that is 21 kcal/mol lower than the kinetic insertion product. The reactions of the chelate opening by ethylene that start from the lowest energy complexes have the lowest barrier for the four-member ring (23 kcal/mol) and the highest for the six-member structure (30.4 kcal/mol). The high barrier for the opening of the six-member chelate suggests the possibility of a two-step chelate-opening mechanism. The internal barriers for the chelate-opening reactions starting from the higher energy complexes are lower then the one-step reaction that starts from the preferred complex and comparable to those of the ethylene insertion into the Pd-alkyl bond. While the chelate opening by a subsequent acrylate insertion seems to be facile for the generic catalyst, steric effects in the real catalyst are likely to decrease the acrylate pi-complexation energies and increase the insertion barriers to the extent where such a reaction becomes unfeasible.
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63
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Heistermann M, Ziegler T, van Schaik CP, Launhardt K, Winkler P, Hodges JK. Loss of oestrus, concealed ovulation and paternity confusion in free-ranging Hanuman langurs. Proc Biol Sci 2001; 268:2445-51. [PMID: 11747562 PMCID: PMC1088898 DOI: 10.1098/rspb.2001.1833] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Ovarian cycles in catarrhine primates are uniquely characterized by prolonged periods of sexual activity in which the timings of ovulation and copulation do not necessarily correspond. According to current hypotheses of primate social evolution, extended sexuality in multi-male groups might represent part of a female strategy to confuse paternity in order to reduce the risk of infanticide by males. We test this hypothesis by examining mating behaviour in relation to timing of ovulation and paternity outcome in a multi-male group of free-living Hanuman langurs. Using faecal progestogen measurements, we first document that female langurs have extended receptive periods in which the timing of ovulation is highly variable. Next, we demonstrate the capacity for paternity confusion by showing that ovulation is concealed from males and that copulations progressively decline throughout the receptive phase. Finally, we demonstrate multiple paternity, and show that despite a high degree of monopolization of receptive females by the dominant male, non-dominant males father a substantial proportion of offspring. We believe that this is the first direct evidence that extended periods of sexual activity in catarrhine primates may have evolved as a female strategy to confuse paternity.
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64
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Zurek E, Ziegler T. A combined quantum mechanical and statistical mechanical study of the equilibrium of trimethylaluminum (TMA) and oligomers of (AlOCH(3))(n) found in methylaluminoxane (MAO) solution. Inorg Chem 2001; 40:3279-92. [PMID: 11421671 DOI: 10.1021/ic001444z] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Density Functional Theory (DFT) has been used to calculate the energies of over 30 different structures with the general formula (AlOMe)(n).(AlMe(3))(m) where n ranges from 6 to 13 and m ranges between 1 and 4, depending upon the structure of the parent (AlOMe)(n) cage. The way in which TMA (trimethylaluminum) bonds to MAO (methylaluminoxane) has been determined as well as the location of the acidic sites present in MAO caged structures. Topological arguments have been used to show that TMA does not bind to MAO cages where n = 12 or n > or = 14. The ADF energies in conjunction with frequency calculations based on molecular mechanics have been used to estimate the finite temperature enthalpies, entropies, and free energies of the TMA containing MAO structures. Using the Gibbs free energies found for pure MAO structures calculated in a previous work, in conjunction with the free energies of TMA containing MAO structures obtained in the present study, it was possible to determine the percent abundance of each TMA containing MAO within the temperature range of 198.15 K-598.15 K. We have found that very little TMA is actually bound to MAO. The Me/Al ratio on the MAO cages is determined as being approximately 1.00, 1.01, 1.02, and 1.03 at 198, 298, 398, and 598 K, respectively. Moreover, the percentage of Al found as TMA has been calculated as being 0.21%, 0.62%, 1.05%, and 1.76% and the average unit formulas of (AlOMe)(18.08).(TMA)(0.04), (AlOMe)(17.04).(TMA)(0.11), (AlOMe)(15.72).(TMA)(0.17), and (AlOMe)(14.62).(TMA)(0.26) have been determined at the aforementioned temperatures.
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65
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Patchkovskii S, Autschbach J, Ziegler T. Curing difficult cases in magnetic properties prediction with self-interaction corrected density functional theory. J Chem Phys 2001. [DOI: 10.1063/1.1370527] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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66
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Autschbach J, Ziegler T. A theoretical investigation of the remarkable nuclear spin-spin coupling pattern in [(NC)(5)Pt-Tl(CN)](-). J Am Chem Soc 2001; 123:5320-4. [PMID: 11457395 DOI: 10.1021/ja003866d] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We address the problem of the interpretation of heavy nucleus spin-spin couplings for systems being studied in solution. Solvation can create counterintuitive features concerning the spin-spin couplings, which are enhanced by relativistic effects due to the presence of heavy nuclei. This should therefore be taken into consideration for the discussion of spectra obtained from solution. Evidence for such solvent effects is provided by a relativistic density functional study of [(NC)(5)Pt-Tl(CN)](-) (I). It is demonstrated that the remarkable experimentally observed spin-spin coupling pattern, e.g., (2)J(Tl-C) >> (1)J(Tl-C) and J(Pt-Tl) approximately 57 kHz, is semiquantitatively reproduced by our calculations if both relativistic effects and solvation are taken into account. Solvent effects are very substantial and shift the Pt-Tl coupling by more than 100%, e.g. Relativistic increase of s-orbital density at the heavy nuclei, charge donation by the solvent, and the specific features of the multicenter C-Pt-Tl-C bond are responsible for the observed coupling pattern.
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67
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Patchkovskii S, Ziegler T. Calculation of the EPR g-Tensors of High-Spin Radicals with Density Functional Theory. J Phys Chem A 2001. [DOI: 10.1021/jp010457a] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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68
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Keller PF, Verin V, Ziegler T, Mermillod B, Popowski Y, Delafontaine P. Gamma-Irradiation Markedly Inhibits the Hydrated Collagen Gel Contraction by Arterial Smooth Muscle Cells. J Investig Med 2001; 49:258-64. [PMID: 11352183 DOI: 10.2310/6650.2001.33970] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
BACKGROUND Vessel wall responses to percutaneous transluminal coronary angioplasty include neointimal proliferation and arterial remodeling. The contraction of a collagen gel is a good in vitro model of wound repair and vascular remodeling. Because irradiation is an important new therapeutic modality capable of preventing restenosis, the purpose of this study was to evaluate the effect of irradiation on the contraction of a collagen gel by smooth muscle cells (SMCs), on SMCs viability, and on DNA synthesis. METHODS We studied the effect of different doses of gamma-irradiation (0 [control], 6, 12, and 18 Gy) on the contraction of a collagen gel seeded with SMCs (calf carotid arteries) during a period of 15 days. RESULTS Maximal gel diameter reduction (from 35 to 6.8 mm, +/-0.5 mm in control) was markedly inhibited in the 6-, 12-, and 18-Gy groups (35 to 13.7 mm, +/-0.8 mm; 35 to 15.5 mm, +/-0.9 mm; and 35 to 16.1 mm, +/-0.9 mm, respectively; P<0.0001). The irradiated gels showed a dose-dependent reduction in the SMC proliferation rate (P<0.0001) and an increase in the number of nonviable SMCs (P<0.002) 15 days after irradiation. CONCLUSIONS Gamma-irradiation produces a significant dose-dependent inhibition of the contraction of collagen gels seeded with arterial SMCs. This effect is related to a significant decrease in SMC viability and a decrease in SMC proliferation rate. These findings shed light on mechanisms whereby irradiation may positively affect arterial remodeling after percutaneous transluminal coronary angioplasties.
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69
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Autschbach J, Ziegler T. Solvent effects on heavy atom nuclear spin-spin coupling constants: a theoretical study of Hg-C and Pt-P couplings. J Am Chem Soc 2001; 123:3341-9. [PMID: 11457070 DOI: 10.1021/ja003481v] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The computation of indirect nuclear spin-spin coupling constants, based on the relativistic two-component zeroth order regular approximate Hamiltonian, has been recently implemented by us into the Amsterdam Density Functional program. Applications of the code for the calculation of one-bond metal-ligand couplings of coordinatively unsaturated compounds containing (195)Pt and (199)Hg, including spin-orbit coupling or coordination effects by solvent molecules, show that relativistic density functional calculations are able to reproduce the experimental findings with good accuracy for the systems under investigation. Spin-orbit effects are rather small for these cases, while coordination of the heavy atoms by solvent molecules has a great impact on the calculated couplings. Experimental trends for different solvents are reproduced. An orbital-based analysis of the solvent effect is presented. The scalar relativistic increase of the coupling constants is of the same order of magnitude as the nonrelativistically obtained values, making a relativistic treatment essential for obtaining quantitatively correct results. Solvent effects can be of similar importance.
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70
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Meenakshi C, Ramamoorthy V, Muthusubramanian S, Sivasubramanian S, Ziegler T, Lex J. Crystal structure of 2-(4-methoxyphenyl)-2-cyclohexene-1-one oxime, C13H15NO2. Z KRIST-NEW CRYST ST 2001. [DOI: 10.1524/ncrs.2001.216.14.685] [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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71
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Marttila J, Hinkkanen A, Ziegler T, Vainionpää R, Salmi A, Ilonen J. Cell membrane-associated measles virus components inhibit antigen processing. Virology 2001; 279:422-8. [PMID: 11162798 DOI: 10.1006/viro.2000.0701] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Measles virus (MV)-induced immune suppression is an important reason for MV-associated mortality and morbidity. Despite numerous studies, the mechanisms of immune suppression still remain poorly defined. In the present study we analyzed the effect of MV components on the T-cell recognition of specific non-MV antigens. We demonstrated that even inactivated MV could inhibit the presentation of unprocessed protein antigen to specific T cells, whereas MV did not affect the responses of specific T cells to representative synthetic peptide epitopes derived from complex antigens. The inhibition was induced by MV-infected cell membranes. The kinetics of the MV-dependent inhibition suggested an impaired antigen processing in mononuclear cells as addition of MV-infected cell debris 4 h after the beginning of cell cultures no longer inhibited T-cell responsiveness.
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72
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Zurek E, Woo TK, Firman TK, Ziegler T. Modeling the dynamic equilibrium between oligomers of (AlOCH3)n in methylaluminoxane (MAO). A theoretical study based on a combined quantum mechanical and statistical mechanical approach. Inorg Chem 2001; 40:361-70. [PMID: 11170544 DOI: 10.1021/ic000845b] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Density functional theory (DFT) has been used to calculate the energies of 36 different methylaluminoxane (MAO) cage structures with the general formula (MeAlO)n, where n ranges from 4 to 16. A least-squares fit has been used to devise a formula which predicts the total energies of the MAO with different n's giving an rms deviation of 4.70 kcal/mol. These energies in conjunction with frequency calculations based on molecular mechanics have been used to estimate the finite temperature enthalpies, entropies, and free energies for these MAO structures. Furthermore, formulas have been devised which predict finite temperature enthalpies and entropies for MAO structures of any n for a temperature range of 198.15-598.15 K. Using these formulas, the free energies at different temperatures have been predicted for MAO structures where n ranges from 17 to 30. The free energy values were then used to predict the percentage of each n found at a given temperature. Our calculations give an average n value of 18.41, 17.23, 16.89, and 15.72 at 198.15, 298.15, 398.15, and 598.15 K, respectively. Topological arguments have also been used to show that the MAO cage structure contains a limited amount of square faces as compared to octagonal and hexagonal ones. It is also suggested that the limited number of square faces with their strained Al-O bonds explain the high molar Al:catalyst ratio required for activation. Moreover, in this study we outline a general methodology which may be used to calculate the percent abundance of an equilibrium mixture of oligomers with the general formula (X)n.
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73
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te Velde G, Bickelhaupt FM, Baerends EJ, Fonseca Guerra C, van Gisbergen SJA, Snijders JG, Ziegler T. Chemistry with ADF. J Comput Chem 2001. [DOI: 10.1002/jcc.1056] [Citation(s) in RCA: 7830] [Impact Index Per Article: 340.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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74
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Ziegler T, Winkler C. [Unusual cause of leg venous thrombosis in a 20-year-old man]. Wien Klin Wochenschr 2000; 112:1039. [PMID: 11204313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
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75
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Ziegler T, Winkler C, Wege K, Schmechel H. [Doxycycline--the forgotten antibiotic]. MEDIZINISCHE KLINIK (MUNICH, GERMANY : 1983) 2000; 95:629-31. [PMID: 11143543 DOI: 10.1007/pl00002075] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Doxycycline is an broad-spectrum antimicrobial agent, it remains an inexpensive alternative for the treatment of community-acquired respiratory infections and urinary tract infections. Despite these clinical data the use of doxycycline has decreased during the last years. PHARMACOLOGY Adverse effects and resistance to therapy are infrequent and not different to fluoroquinolones and macrolide antibiotics. Gastrointestinal and phototoxic side effects are of importance. After oral administration 75% will be absorbed and largely eliminated by the hepatic and intestinal way. Contraindications are severe liver dysfunction and treatment in childhood. CLINICAL INDICATIONS Bacterial resistance to doxycycline has a low incidence in Germany. A therapeutic success can be expected in respiratory and urinary tract infections in about 80%. Doxycycline is the drug of choice for treating infections caused by Rickettsia, Borrelia, Ehrlichia. It shows good activity against Plasmodium falciparum as one part in a combination therapy. Daily costs of therapy are low, in oral administration DM 0.80 per day, in i.v. administration DM 22,-per day. CONCLUSION Despite competition from new antibiotics, doxycycline can retain an important place in the treatment of many infectious diseases.
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