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Nenoff P, Koch D, Krüger C, Drechsel C, Mayser P. New insights on the antibacterial efficacy of miconazole in vitro. Mycoses 2017; 60:552-557. [PMID: 28370366 DOI: 10.1111/myc.12620] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 02/25/2017] [Accepted: 03/03/2017] [Indexed: 11/29/2022]
Abstract
Miconazole is a broad-spectrum antifungal used in topical preparations. In the present investigation the minimal inhibitory concentration (MIC) of miconazole for eighty wild type strains of gram-positive and gram-negative bacteria isolated from infected skin lesions was assessed using a modified agar dilution test (adapted to CLSI, Clinical Laboratory Standards Institute). 14 ATCC reference strains served as controls. Miconazole was found efficacious against gram-positive aerobic bacteria (n=62 species), the MICs against Staphylococcus (S.) aureus, S. spp., Streptococcus spp. und Enterococcus spp. ranged between 0.78 and 6.25 μg/mL. Interestingly, there were no differences in susceptibility between methicillin-susceptible (MSSA, 3) methicillin-resistant (MRSA, 6) and fusidic acid-resistant (FRSA, 2) S. aureus isolates. Strains of Streptococcus pyogenes (A-streptococci) (8) were found to be slightly more sensitive (0.78-1.563 μg/mL), while for gram-negative bacteria, no efficacy was found within the concentrations tested (MIC >200 μg/mL). In conclusion, for the gram-positive aerobic bacteria the MICs of miconazole were found within a range which is much lower than the concentration of miconazole used in topical preparations (2%). Thus topically applied miconazole might be a therapeutic option in skin infections especially caused by gram-positive bacteria even by those strains which are resistant to antibiotics.
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Aartsen MG, Abraham K, Ackermann M, Adams J, Aguilar JA, Ahlers M, Ahrens M, Altmann D, Andeen K, Anderson T, Ansseau I, Anton G, Archinger M, Argüelles C, Auffenberg J, Axani S, Bai X, Barwick SW, Baum V, Bay R, Beatty JJ, Becker Tjus J, Becker KH, BenZvi S, Berghaus P, Berley D, Bernardini E, Bernhard A, Besson DZ, Binder G, Bindig D, Bissok M, Blaufuss E, Blot S, Bohm C, Börner M, Bos F, Bose D, Böser S, Botner O, Braun J, Brayeur L, Bretz HP, Burgman A, Carver T, Casier M, Cheung E, Chirkin D, Christov A, Clark K, Classen L, Coenders S, Collin GH, Conrad JM, Cowen DF, Cross R, Day M, de André JPAM, De Clercq C, Del Pino Rosendo E, Dembinski H, De Ridder S, Desiati P, de Vries KD, de Wasseige G, de With M, DeYoung T, Díaz-Vélez JC, di Lorenzo V, Dujmovic H, Dumm JP, Dunkman M, Eberhardt B, Ehrhardt T, Eichmann B, Eller P, Euler S, Evenson PA, Fahey S, Fazely AR, Feintzeig J, Felde J, Filimonov K, Finley C, Flis S, Fösig CC, Franckowiak A, Friedman E, Fuchs T, Gaisser TK, Gallagher J, Gerhardt L, Ghorbani K, Giang W, Gladstone L, Glagla M, Glüsenkamp T, Goldschmidt A, Golup G, Gonzalez JG, Grant D, Griffith Z, Haack C, Haj Ismail A, Hallgren A, Halzen F, Hansen E, Hansmann B, Hansmann T, Hanson K, Hebecker D, Heereman D, Helbing K, Hellauer R, Hickford S, Hignight J, Hill GC, Hoffman KD, Hoffmann R, Holzapfel K, Hoshina K, Huang F, Huber M, Hultqvist K, In S, Ishihara A, Jacobi E, Japaridze GS, Jeong M, Jero K, Jones BJP, Jurkovic M, Kappes A, Karg T, Karle A, Katz U, Kauer M, Keivani A, Kelley JL, Kemp J, Kheirandish A, Kim M, Kintscher T, Kiryluk J, Kittler T, Klein SR, Kohnen G, Koirala R, Kolanoski H, Konietz R, Köpke L, Kopper C, Kopper S, Koskinen DJ, Kowalski M, Krings K, Kroll M, Krückl G, Krüger C, Kunnen J, Kunwar S, Kurahashi N, Kuwabara T, Labare M, Lanfranchi JL, Larson MJ, Lauber F, Lennarz D, Lesiak-Bzdak M, Leuermann M, Leuner J, Lu L, Lünemann J, Madsen J, Maggi G, Mahn KBM, Mancina S, Mandelartz M, Maruyama R, Mase K, Maunu R, McNally F, Meagher K, Medici M, Meier M, Meli A, Menne T, Merino G, Meures T, Miarecki S, Mohrmann L, Montaruli T, Moulai M, Nahnhauer R, Naumann U, Neer G, Niederhausen H, Nowicki SC, Nygren DR, Obertacke Pollmann A, Olivas A, O'Murchadha A, Palczewski T, Pandya H, Pankova DV, Penek Ö, Pepper JA, Pérez de Los Heros C, Pieloth D, Pinat E, Price PB, Przybylski GT, Quinnan M, Raab C, Rädel L, Rameez M, Rawlins K, Reimann R, Relethford B, Relich M, Resconi E, Rhode W, Richman M, Riedel B, Robertson S, Rongen M, Rott C, Ruhe T, Ryckbosch D, Rysewyk D, Sabbatini L, Sanchez Herrera SE, Sandrock A, Sandroos J, Sarkar S, Satalecka K, Schimp M, Schlunder P, Schmidt T, Schoenen S, Schöneberg S, Schumacher L, Seckel D, Seunarine S, Soldin D, Song M, Spiczak GM, Spiering C, Stahlberg M, Stanev T, Stasik A, Steuer A, Stezelberger T, Stokstad RG, Stößl A, Ström R, Strotjohann NL, Sullivan GW, Sutherland M, Taavola H, Taboada I, Tatar J, Tenholt F, Ter-Antonyan S, Terliuk A, Tešić G, Tilav S, Toale PA, Tobin MN, Toscano S, Tosi D, Tselengidou M, Turcati A, Unger E, Usner M, Vandenbroucke J, van Eijndhoven N, Vanheule S, van Rossem M, van Santen J, Veenkamp J, Vehring M, Voge M, Vraeghe M, Walck C, Wallace A, Wallraff M, Wandkowsky N, Weaver C, Weiss MJ, Wendt C, Westerhoff S, Whelan BJ, Wickmann S, Wiebe K, Wiebusch CH, Wille L, Williams DR, Wills L, Wolf M, Wood TR, Woolsey E, Woschnagg K, Xu DL, Xu XW, Xu Y, Yanez JP, Yodh G, Yoshida S, Zoll M. Constraints on Ultrahigh-Energy Cosmic-Ray Sources from a Search for Neutrinos above 10 PeV with IceCube. PHYSICAL REVIEW LETTERS 2016; 117:241101. [PMID: 28009216 DOI: 10.1103/physrevlett.117.241101] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Indexed: 06/06/2023]
Abstract
We report constraints on the sources of ultrahigh-energy cosmic rays (UHECRs) above 10^{9} GeV, based on an analysis of seven years of IceCube data. This analysis efficiently selects very high- energy neutrino-induced events which have deposited energies from 5×10^{5} GeV to above 10^{11} GeV. Two neutrino-induced events with an estimated deposited energy of (2.6±0.3)×10^{6} GeV, the highest neutrino energy observed so far, and (7.7±2.0)×10^{5} GeV were detected. The atmospheric background-only hypothesis of detecting these events is rejected at 3.6σ. The hypothesis that the observed events are of cosmogenic origin is also rejected at >99% CL because of the limited deposited energy and the nonobservation of events at higher energy, while their observation is consistent with an astrophysical origin. Our limits on cosmogenic neutrino fluxes disfavor the UHECR sources having a cosmological evolution stronger than the star formation rate, e.g., active galactic nuclei and γ-ray bursts, assuming proton-dominated UHECRs. Constraints on UHECR sources including mixed and heavy UHECR compositions are obtained for models of neutrino production within UHECR sources. Our limit disfavors a significant part of parameter space for active galactic nuclei and new-born pulsar models. These limits on the ultrahigh-energy neutrino flux models are the most stringent to date.
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Nenoff P, Overbeck C, Uhrlaß S, Krüger C, Gräser Y. Tinea corporis durch den seltenen geophilen Dermatophyten Microsporum praecox. Hautarzt 2016; 68:396-402. [PMID: 27586990 DOI: 10.1007/s00105-016-3867-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Uhrlaß S, Krüger C, Nenoff P. [Microsporum canis: Current data on the prevalence of the zoophilic dermatophyte in central Germany]. Hautarzt 2016; 66:855-62. [PMID: 26446665 DOI: 10.1007/s00105-015-3697-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
BACKGROUND Microsporum (M.) canis, whose source of infection is mostly cats, is still considered as the most frequently occurring zoophilic dermatophyte in Germany and Europe. In distinct areas of Germany, the zoophilic dermatophyte Trichophyton (T.) anamorph of Arthroderma (A.) benhamiae also presents a frequent and emerging causative agent of dermatophytoses. MATERIALS AND METHODS Over a period of 3 years, from March 2010 to March 2013, skin samples from scalp, face, trunk, and limbs were investigated using mycological cultivation and by polymerase chain reaction (PCR) for dermatophytes. Materials originated in particular from the German Free States Saxony and Thuringia, and from the Federal State Saxony-Anhalt, but also included samples submitted from around Germany. The cultural detection of dermatophytes was performed on Sabouraud's 4% glucose agar with and without cycloheximide. For dermatophyte DNA detection, a uniplex PCR-ELISA was used. RESULTS In all, 8464 samples from a total of 7680 patients were investigated. In 114 (1.5%) of 7680 patients, M. canis could be detected both by culture and/or PCR. M. canis was detected culturally in 100 samples, in 107 samples by PCR, in 91 samples both culturally and by PCR. For 12 patients, only cultural detection was done (without PCR). Also detected was tinea corporis due to M. canis in 59 patients, tinea capitis 8, tinea faciei 5, and tinea manus 2 patients. Of the patients, 45% were younger than 20 years, 42% were 20-49 years old, and 13% were 50 years or older. In comparison, T. anamorph of A. benhamiae was detectable by culture and/or PCR in 231 of 7680 patients (2.9%). M. canis was the second most common zoophilic dermatophyte. CONCLUSIONS M. canis is still a frequent zoophilic dermatophyte in Germany. Since a few years ago, a rise of infections due to T. anamorph of A. benhamiae has been observed in Germany and other European countries. At least in distinct regions of Germany, this zoophilic dermatophyte, which is transferred from guinea pigs to human beings, currently seems to be more frequent when compared to M. canis.
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Aartsen MG, Abraham K, Ackermann M, Adams J, Aguilar JA, Ahlers M, Ahrens M, Altmann D, Andeen K, Anderson T, Ansseau I, Anton G, Archinger M, Argüelles C, Arlen TC, Auffenberg J, Axani S, Bai X, Barwick SW, Baum V, Bay R, Beatty JJ, Becker Tjus J, Becker KH, BenZvi S, Berghaus P, Berley D, Bernardini E, Bernhard A, Besson DZ, Binder G, Bindig D, Blaufuss E, Blot S, Boersma DJ, Bohm C, Börner M, Bos F, Bose D, Böser S, Botner O, Braun J, Brayeur L, Bretz HP, Burgman A, Casey J, Casier M, Cheung E, Chirkin D, Christov A, Clark K, Classen L, Coenders S, Collin GH, Conrad JM, Cowen DF, Cruz Silva AH, Daughhetee J, Davis JC, Day M, de André JPAM, De Clercq C, Del Pino Rosendo E, Dembinski H, De Ridder S, Desiati P, de Vries KD, de Wasseige G, de With M, DeYoung T, Díaz-Vélez JC, di Lorenzo V, Dujmovic H, Dumm JP, Dunkman M, Eberhardt B, Ehrhardt T, Eichmann B, Euler S, Evenson PA, Fahey S, Fazely AR, Feintzeig J, Felde J, Filimonov K, Finley C, Flis S, Fösig CC, Fuchs T, Gaisser TK, Gaior R, Gallagher J, Gerhardt L, Ghorbani K, Giang W, Gladstone L, Glüsenkamp T, Goldschmidt A, Golup G, Gonzalez JG, Góra D, Grant D, Griffith Z, Haj Ismail A, Hallgren A, Halzen F, Hansen E, Hanson K, Hebecker D, Heereman D, Helbing K, Hellauer R, Hickford S, Hignight J, Hill GC, Hoffman KD, Hoffmann R, Holzapfel K, Homeier A, Hoshina K, Huang F, Huber M, Huelsnitz W, Hultqvist K, In S, Ishihara A, Jacobi E, Japaridze GS, Jeong M, Jero K, Jones BJP, Jurkovic M, Kappes A, Karg T, Karle A, Katz U, Kauer M, Keivani A, Kelley JL, Kheirandish A, Kim M, Kintscher T, Kiryluk J, Kittler T, Klein SR, Kohnen G, Koirala R, Kolanoski H, Köpke L, Kopper C, Kopper S, Koskinen DJ, Kowalski M, Krings K, Kroll M, Krückl G, Krüger C, Kunnen J, Kunwar S, Kurahashi N, Kuwabara T, Labare M, Lanfranchi JL, Larson MJ, Lennarz D, Lesiak-Bzdak M, Leuermann M, Lu L, Lünemann J, Madsen J, Maggi G, Mahn KBM, Mancina S, Mandelartz M, Maruyama R, Mase K, Maunu R, McNally F, Meagher K, Medici M, Meier M, Meli A, Menne T, Merino G, Meures T, Miarecki S, Middell E, Mohrmann L, Montaruli T, Moulai M, Nahnhauer R, Naumann U, Neer G, Niederhausen H, Nowicki SC, Nygren DR, Obertacke Pollmann A, Olivas A, Omairat A, O'Murchadha A, Palczewski T, Pandya H, Pankova DV, Pepper JA, Pérez de Los Heros C, Pfendner C, Pieloth D, Pinat E, Posselt J, Price PB, Przybylski GT, Quinnan M, Raab C, Rameez M, Rawlins K, Relich M, Resconi E, Rhode W, Richman M, Riedel B, Robertson S, Rott C, Ruhe T, Ryckbosch D, Rysewyk D, Sabbatini L, Salvado J, Sanchez Herrera SE, Sandrock A, Sandroos J, Sarkar S, Satalecka K, Schlunder P, Schmidt T, Schöneberg S, Schönwald A, Seckel D, Seunarine S, Soldin D, Song M, Spiczak GM, Spiering C, Stamatikos M, Stanev T, Stasik A, Steuer A, Stezelberger T, Stokstad RG, Stößl A, Ström R, Strotjohann NL, Sullivan GW, Sutherland M, Taavola H, Taboada I, Tatar J, Ter-Antonyan S, Terliuk A, Tešić G, Tilav S, Toale PA, Tobin MN, Toscano S, Tosi D, Tselengidou M, Turcati A, Unger E, Usner M, Vallecorsa S, Vandenbroucke J, van Eijndhoven N, Vanheule S, van Rossem M, van Santen J, Veenkamp J, Voge M, Vraeghe M, Walck C, Wallace A, Wandkowsky N, Weaver C, Wendt C, Westerhoff S, Whelan BJ, Wiebe K, Wille L, Williams DR, Wills L, Wissing H, Wolf M, Wood TR, Woolsey E, Woschnagg K, Xu DL, Xu XW, Xu Y, Yanez JP, Yodh G, Yoshida S, Zoll M. Searches for Sterile Neutrinos with the IceCube Detector. PHYSICAL REVIEW LETTERS 2016; 117:071801. [PMID: 27563950 DOI: 10.1103/physrevlett.117.071801] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Indexed: 06/06/2023]
Abstract
The IceCube neutrino telescope at the South Pole has measured the atmospheric muon neutrino spectrum as a function of zenith angle and energy in the approximate 320 GeV to 20 TeV range, to search for the oscillation signatures of light sterile neutrinos. No evidence for anomalous ν_{μ} or ν[over ¯]_{μ} disappearance is observed in either of two independently developed analyses, each using one year of atmospheric neutrino data. New exclusion limits are placed on the parameter space of the 3+1 model, in which muon antineutrinos experience a strong Mikheyev-Smirnov-Wolfenstein-resonant oscillation. The exclusion limits extend to sin^{2}2θ_{24}≤0.02 at Δm^{2}∼0.3 eV^{2} at the 90% confidence level. The allowed region from global analysis of appearance experiments, including LSND and MiniBooNE, is excluded at approximately the 99% confidence level for the global best-fit value of |U_{e4}|^{2}.
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Krüger C, Schuler-Lüttmann S, Haug T, Gantert M, Hermsen M. Multidrug-Resistant Bacteria in Refugee Children and Pregnant Women Admitted to a General Hospital in North Rhine-Westphalia, Germany. KLINISCHE PADIATRIE 2016; 228:227-9. [DOI: 10.1055/s-0042-109711] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Schüßler A, Krüger C, Urgiles N. Phylogenetically diverse AM fungi from Ecuador strongly improve seedling growth of native potential crop trees. MYCORRHIZA 2016; 26:199-207. [PMID: 26260945 DOI: 10.1007/s00572-015-0659-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2014] [Accepted: 07/27/2015] [Indexed: 06/04/2023]
Abstract
In many deforested regions of the tropics, afforestation with native tree species could valorize a growing reservoir of degraded, previously overused and abandoned land. The inoculation of tropical tree seedlings with arbuscular mycorrhizal fungi (AM fungi) can improve tree growth and viability, but efficiency may depend on plant and AM fungal genotype. To study such effects, seven phylogenetically diverse AM fungi, native to Ecuador, from seven genera and a non-native AM fungus (Rhizophagus irregularis DAOM197198) were used to inoculate the tropical potential crop tree (PCT) species Handroanthus chrysanthus (synonym Tabebuia chrysantha), Cedrela montana, and Heliocarpus americanus. Twenty-four plant-fungus combinations were studied in five different fertilization and AMF inoculation treatments. Numerous plant growth parameters and mycorrhizal root colonization were assessed. The inoculation with any of the tested AM fungi improved seedling growth significantly and in most cases reduced plant mortality. Plants produced up to threefold higher biomass, when compared to the standard nursery practice. AM fungal inoculation alone or in combination with low fertilization both outperformed full fertilization in terms of plant growth promotion. Interestingly, root colonization levels for individual fungi strongly depended on the host tree species, but surprisingly the colonization strength did not correlate with plant growth promotion. The combination of AM fungal inoculation with a low dosage of slow release fertilizer improved PCT seedling performance strongest, but also AM fungal treatments without any fertilization were highly efficient. The AM fungi tested are promising candidates to improve management practices in tropical tree seedling production.
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Nenoff P, Krüger C, Mayser P. Kutane Malassezia-Infektionen und Malassezia-assoziierte Dermatosen. Hautarzt 2015; 66:465-84; quiz 485-6. [DOI: 10.1007/s00105-015-3631-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Nenoff P, Reinel D, Krüger C, Grob H, Mugisha P, Süß A, Mayser P. Tropen- und Reise-assoziierte Dermatomykosen. Hautarzt 2015; 66:522-32. [DOI: 10.1007/s00105-015-3635-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Krüger C, Köhler H, Liebler-Tenorio EM. Cellular composition of granulomatous lesions in gut-associated lymphoid tissues of goats during the first year after experimental infection with Mycobacterium avium subsp. paratuberculosis. Vet Immunol Immunopathol 2014; 163:33-45. [PMID: 25466387 DOI: 10.1016/j.vetimm.2014.11.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Revised: 10/28/2014] [Accepted: 11/05/2014] [Indexed: 10/24/2022]
Abstract
Mycobacterium avium subsp. paratuberculosis (MAP) causes lesions in naturally and experimentally infected ruminants which greatly differ in severity, cellular composition and number of mycobacteria. Morphologically distinct lesions are already found during the clinically inapparent phase of infection. The complex local host response and number of MAP were characterized at the initial sites of lesions, organized gut-associated lymphoid tissue, in experimentally infected goats. Tissues were collected at 3, 6, 9 and 12 month post-inoculation (mpi) from goat kids that had orally received 10 times 10mg of bacterial wet mass of MAP (JII-1961). The cellular composition of lesions in Peyer's patches in the jejunum and next to the ileocecal valve was evaluated in 21 MAP-inoculated goats, where lesions were compared with unaltered tissue of six control goats. CD68+, CD4+, CD8+, γδ T lymphocytes, B lymphocytes and plasma cells, MHC class II+ and CD25+ cells were demonstrated by immunohistochemistry in serial cryostat sections. At 3 mpi, extensive granulomatous infiltrates predominated, consisting of numerous epitheloid cells admixed with many CD4 and γδ T lymphocytes. Only single MAP were detected. This indicates a strong cellular immune reaction able to control MAP infection. γδ T lymphocytes were markedly increased in this type of lesion which may reflect their important role early in the pathogenesis of paratuberculosis. At 9 and 12 mpi, divergent lesions were observed which may reflect different outcomes of host-pathogen interactions. In five goats, minimal granulomatous lesions were surrounded by extensive lymphoplasmacytic infiltrates and no MAP were detected by immunohistochemistry. This was interpreted as effective host response that was able to eliminate MAP locally. In three goats, decreased numbers of lymphocytes, but extensive granulomatous infiltrates with numerous epitheloid cells containing increased numbers of mycobacteria were seen. This shift of the immune response resulted in uncontrolled mycobacterial multiplication. Focal and multifocal circumscribed granulomatous infiltrates of mainly epitheloid cells may represent sites of new infection, since they were observed in goats at all times after inoculation. Their presence in goats with minimal granulomatous lesions surrounded by extensive lymphoplasmacytic infiltrates may indicate that despite the local clearance, the infection may be perpetuated. The complex cellular immune reactions postulated for the pathogenesis of paratuberculosis were demonstrated at the local sites of infection. These early host-pathogen interactions are most likely essential for the eventual outcome of the MAP infection.
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Bergh AM, Van Staden CW, Joubert PM, Krüger C, Pickworth GE, Roos JL, Schurink WJ, Du Preez RR, Grey SV, Lindeque BG. Medical students' perceptions of their development of ‘soft skills’ Part II: The development of ‘soft skills’ through ‘guiding and growing’. S Afr Fam Pract (2004) 2014. [DOI: 10.1080/20786204.2006.10873436] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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Schurink WJ, Krüger C, Bergh AM, Van Staden CW, Roos JL, Pickworth GE, Joubert PM, Du Preez RR, Grey SV, Lindeque BG. Medical students' perceptions of their development of ‘soft skills’ Part I: A qualitative research methodology. S Afr Fam Pract (2004) 2014. [DOI: 10.1080/20786204.2006.10873435] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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Krüger C, Blitz-Lindeque JJ, Pickworth GE, Munro AJ, Lotriet M. Communication skills for medical/dental students at the University of Pretoria: Lessons learnt from a two-year study using a forum theatre method. S Afr Fam Pract (2004) 2014. [DOI: 10.1080/20786204.2005.10873249] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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Krüger C, Goddard R, Claus KH. Die experimentelle Bestimmung der Elektronendichteverteilung in einem Chrom-Carben- sowie einem Chrom-Carbin-Komplex / The Experimental Determination of the Electronic Deformation Densities in a Chromium Carbene and a Chromium Carbyne Complex. ACTA ACUST UNITED AC 2014. [DOI: 10.1515/znb-1983-1119] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
The electronic deformation densities for pentacarbonylmethylethoxycarbenechromium I and chlorotetracarbonylethylidynechromium II have been experimentally determined using Neutron (for I) and X-ray diffracted intensities measured from single crystals at 100 K. A build up of electron density in all bonds and around each chromium atom is observed. Deformation density maxima are directed along the 3-fold axes of the approx-imately octahedrally coordinated metal atoms and presumably represent occupation of the t2g d-orbital set. The observed electron density distributions indicate that intermole-cular bonding has an important influence on the distribution of electron density in the molecules.
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Koerner Von Gustorf E, Grevels FW, Krüger C, Olbrich G, Mark F, Schulz D, Wagner R. Photochemische Synthese von Pinocarvon-, Pulegon- und Benzalacetophenon-tricarbonyleisen. Ein Beitrag zur Frage der Bindung α, β-ungesättigter Ketone in Eisen-Komplexen / Photochemical Synthesis of Pinocarvone-, Pulegone-, and Benzalacetophenone-tricarbonyliron. A Contribution to the Nature of Bonding in Iron-Complexes of α,β-unsaturated Ketones. ACTA ACUST UNITED AC 2014. [DOI: 10.1515/znb-1972-0410] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The photochemical synthesis of the title compounds is described. It has been established by spectroscopic evidence and by the x-ray structure of pinocarvone tricarbonyliron that in all these cases bonding to the iron involves only the π-system of the α,β-unsaturated ketones and not the nonbonding electrons of the keto group. The preferential site of monodentate coordination of α,β-unsaturated carbonyl compounds to transition metals is discussed on the basis of MO-considerations which are extended to 1,2-dicarbonyl compounds.
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Schneider JJ, Denninger U, Krüger C. Zur Reaktion von Natriumtetracarbonylcobaltat mit Aluminiumtrichlorid. Molekiilstruktur von Co4(CO)13Al(THF)3Co3(CO)10 / On the Reaction of Sodium Tetracarbonylcobaltate with Aluminiumtrichlorid. Molecular Structure of Co4(CO)13Al(THF)3Co3(CO)10. ZEITSCHRIFT FUR NATURFORSCHUNG SECTION B-A JOURNAL OF CHEMICAL SCIENCES 2014. [DOI: 10.1515/znb-1994-1116] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The reaction of NaCo(CO)4 with AlCl3 in benzene has been studied. Main product of the reaction is Co4(CO)12. However, fractional crystallization of the crude reaction mixture gives small amounts of black crystals of the cobalt cluster Co4(CO)13Al(THF)3Co3(CO)10
A single crystal structure determination has revealed a quasi-octahedrally coordinated Al atom which is bridging a Co3(CO)9-oxymethylidin-tricobalt-nonacarbonyl cluster unit and a Co4-carbonyl cluster unit. Three THF ligands are completing the octahedral environment of the group-III metal. The aluminium atom is bonded to the oxygen atoms of three μ3-bridging CO groups of the Co3- and Co4-cluster fragments.
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43
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Gabor B, Goddard R, Holle S, Jolly PW, Krüger C, Mynott R, Wisniewski W. The Reaction of Dienes with [Fe(Pri
2P(CH2)nPPri
2)] Species. ACTA ACUST UNITED AC 2014. [DOI: 10.1515/znb-1995-0407] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The structure of the compounds formed upon reacting Fe(Pri
2P(CH2)nPPri
2)Cl2 (n = 1-3) and active-Mg with acyclic and cyclic 1,3-, 1,4- and 1,5-dienes depends upon the nature of the diene and upon the length of the methylene-chain bridging the two P-atoms of the bidentate ligand. For example, isoprene reacts to give either (η4-isoprene)2FePPri
2C2H4PPri
2 or (η4-isoprene)Fe(Pri
2PC3H6PPri
2) while the products of the reaction with 1,5-hexadiene are (η5-1-methylpentadienyl)Fe(Pri
2PC2H4PPri
2)H or (η2,η2-1,5-hexadiene)Fe(Pri
2PC3H6PPri
2). The crystal structures of the last two compounds have been established by X-ray diffraction. The penultimate species catalyses the linear dimerization of 1,5-hexadiene.
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Bitterer F, Brauer DJ, Dörrenbach F, Gol F, Knüppel PC, Stelzer O, Krüger C, Tsay YH. Reduktive Enthalogenierung von (Cl, Br)RP–CH2–PR(Cl, Br) mit Fe2(CO)9– Bildung von Komplexen mit gespannten Diphosphirangerüsten und bifunktionellen Phosphidobrücken (µ2-PR)2CH2 / Reductive Dehalogenation of (Cl, Br)RP–CH2—PR(Cl, Br) with Fe2(CO)9– Formation of Complexes with Strained Diphosphirane Skeletons and Bifunctional Phosphido Bridges (μ2-PR)2CH2. ZEITSCHRIFT FUR NATURFORSCHUNG SECTION B-A JOURNAL OF CHEMICAL SCIENCES 2014. [DOI: 10.1515/znb-1991-0901] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Reductive dehalogenation of the bifunctional methylene bridged halogenphosphines XRP-CH2—PRX (X = Cl, Br; R = iPr, tBu, 2,4,6-R′3C6H2 (R′ = Me, iPr, tBu), N(SiMe3)2 and 2,6,4-tBu2MeC6H2—O) with diironenneacarbonyl affords phosphido complexes with strained RP—CH2—PR backbones, Fe2(CO)6[(μ2-PR)2CH2] (8a-8g). X-Ray structural analyses of the 2,4,6-iPr3C6H2 (8d) and 2,6,4-tBu2MeC6H2—O derivatives (8g) reveal that the Fe2P2C skeletons have remarkably small P—C—P angles (83,7(4)° (8d), 78,6(1)° (8g)).
The dehalogenation of XRP—CH2—PRX with Fe,(CO)9 is preceded by the formation of iron carbonyl complexes (RXP—CH2—PRX)[Fe(CO)4]n (n = 1, 2). For derivatives with bulky substituents R complex formation proceeds diastereoselectively. In case of 3 b the diastereoisomers could be separated and a crystallographic examination of the racemic form showed that the P—C—P backbone possesses C2 symmetry with an approximately trans conformation of the P—C—P fragment. The P-atoms occupy the equatorial position within the Fe(CO)4P units.
The chloro-phosphido bridged complex Fe2(CO)6(μ2-Cl)(µ2-PR—CH2—PRCl—Fe(CO)4) (4a), formed by oxidative addition of a P—Cl bond to Fe(0), or diphosphiranes and their complexes [(RP)2CH2][Fe(CO)4]n (n = 0-2; 5-7) have been isolated as intermediates of the XRP-CH2—PRX dehalogenation. The diphosphiranes 5 were synthesized independently by reduction of the halogenphosphines XRP—CH2—PRX with lithium or magnesium. An X-ray examination of 4a showed that it contains a μ2-PR—CH2—PRCl backbone which bridges Fe2(CO)6(μ2-Cl) and Fe(CO)4 units, the P—C—P angle being remarkably large, 127,3(1)°.
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45
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Kraus HJ, Werner H, Krüger C. Synthese und Struktur von C5Me5Pd(PR3)X: Palladiumkomplexe mit einem unsymmetrisch gebundenen Pentamethylcyclopentadienylring [1] / Synthesis and Structure of C5Me5Pd(PR3)X: Palladium Complexes with an Unsymmetrically Bonded Pentamethylcyclopentadienyl Ring [1]. ZEITSCHRIFT FUR NATURFORSCHUNG SECTION B-A JOURNAL OF CHEMICAL SCIENCES 2014. [DOI: 10.1515/znb-1983-0614] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
The complexes C5Me5Pd(PR3)X (1-4) are prepared from [Cl(PR3)Pd]2(μ-OCOCH3)2 and TIC5Me5. Attempts to replace the halide ligand by a second C5Me5 or a C5H5 unit remained unsuccessful. The X-ray structure analysis of C5Me5Pd[P(i-Pr)3]Cl (3) indicates that the five-membered ring shows a tendency of η1-bonding towards the metal.
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46
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Benn R, Betz P, Goddard R, Jolly PW, Kokel N, Krüger C, Topalović I. Intermediates in the Palladium-Catalyzed Reaction of 1,3-Dienes, Part 6 [1]. ACTA ACUST UNITED AC 2014. [DOI: 10.1515/znb-1991-1018] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The structure of the (1,3-butadiene)M(R2PC2H4PR2) compounds (M = Ni, Pd, Pt; R = Pri, Bu′, Cy) in the solid-state have been investigated by 13C and 31P CP/MAS NMR spectroscopy. The bonding mode adopted by the diene is dependent upon the nature of the metal: the palladium compounds contain an η2-diene molecule, the nickel compound where R is cyclohexyl contains an η4-diene molecule whereas the Pr2
iPC2H4PPr2
i-stabilized platinum compound con- tains a platinacyclopentene ring. The crystal structures of (η2-1,3-C4H6)Pd(Cy2PC2H4PCy2) and (η4-1,3-C4H6)Ni(Cy2PC2H4PCy2) have been confirmed by X-ray diffraction.
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Albini A, Kisch H, Krüger C, Chiang AP. Transition Metal Complexes of Diazenes, XVII [1]. Reactions of 1,2-Diazetines and 1,2-Diazetine-N-oxides with Iron Carbonyls. ACTA ACUST UNITED AC 2014. [DOI: 10.1515/znb-1982-0412] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Enneacarbonyldiiron reacts with 3,3,4,4-tetramethyl-1,2-diazetine (L) or its mono-N-oxide (L′) to form complexes (L)Fe(CO)4 (3), (L)Fe2(CO)7 (4), (L)Fe2(CO)6 (5), or (L′)Fe(CO)4 (6), and small amounts of deoxygenated 4 and 5, respectively. Formation and stability of the complexes is compared with those of ligands with smaller and larger ring sizes and discussed in terms of the electronic properties of the ligand lone-pair Orbitals. The molecular structure of 4 is established by X-ray analysis.
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48
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Kisch H, Krüger C, Marcolin HE, Trautwein AX. Übergangsmetallkomplexe von Diazenen, XXIII [1]. Struktur und Mößbauer-Daten bi- und tricyclischer Ferracyclen / Transition Metal Complexes of Diazenes, XXIII [1] Structure and Mößbauer Data of Bi- and Tricyclic Ferracycles. ZEITSCHRIFT FUR NATURFORSCHUNG SECTION B-A JOURNAL OF CHEMICAL SCIENCES 2014. [DOI: 10.1515/znb-1987-1111] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Mößbauer spectra of mono and dinuclear iron carbonyl complexes of three cyclic diazenes and the crystal structures of two products formed from (cis-diazene)Fe2(CO)6 and alkynes are reported. The ring size of the diazene ligand influences the stereochemistry of the cycloadducts obtained in the latter reaction; the bicyclic diazaferracycloalkene skeleton of these compounds leads to an exo- and endo-arrangement of one iron carbonyl group relative to the five- and six- membered diazene, rcspectively.
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Battaglia R, Kisch H, Krüger C, Liu LK. Übergangsmetallkomplexe von Diazenen, XV [1] Darstellung und Eigenschaften von Heterodimetallkomplexen des Typs LnM-(cis-RN=NR)-MʹLm Transition Metal Complexes of Diazenes, XV [1] Synthesis and Properties of Heterodimetal Complexes LnM-(cis-RN=NR)-MʹLm. ACTA ACUST UNITED AC 2014. [DOI: 10.1515/znb-1980-0616] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Complexes of type LnM(η2 - pentamethylenediazirine)MʹLm, LnM/MʹLm = (CO)5Cr/Mo(CO)5, (CO)5Cr/Fe(CO)4, (CO)5W/Fe(CO)4 and (CO)5Cr/Mn(CO)2
5η(-MeC5H4) were prepared from [MʹLm(THF)] or Fe2(CO)9 and (η1 -pentamethylenediazirine)MLn. The structure of the Cr/Mo complex was determined by X-ray analysis. The IR and UV-VIS data resemble those of the corresponding homodi-metal complexes.
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50
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Kisch H, Krüger C, Trautwein A. Übergangsmetallkomplexe von Diazenen, XVI [1] Struktur und Mößbauerdaten von (2.3-Diazanorbornen)Fe3(CO)9 / Transition Metal Complexes of Diazenes, XVI [1] Structure and Mössbauer Data of (2,3-Diazanorbornene)Fe3(CO)9. ZEITSCHRIFT FUR NATURFORSCHUNG SECTION B-A JOURNAL OF CHEMICAL SCIENCES 2014. [DOI: 10.1515/znb-1981-0215] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
The molecular structure of (2,3-diazanorbornene)Fe3(CO)9 consists of a triangular Fe3(CO)9 group bound to the diazene unit. The seven-coordinated Fe(CO)3 group forms two Fe-N bonds with lengths of 1.974 and 1.965 Å, each of the two six-coordinated Fe(CO)3 groups has slightly shorter Fe-N-bonds of 1.898 and 1.903 Å. One Fe-Fe distance, 2.612Å, is longer than the two other ones, 2.572 and 2.582 Å, which are in the range of typical single bonds. The presence of seven-and six-coordinated iron carbonyl groups is also demonstrated by the Mössbauer spectrum showing signals with quadrupole splittings of 1.23 and 0.78, 0.62 ± 0.01 mm/s, respectively.
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