1
|
Isolation and identification of arbuscular mycorrhizal fungi from an abandoned uranium mine and their role in soil-to-plant transfer of radionuclides and metals. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 876:162781. [PMID: 36906011 DOI: 10.1016/j.scitotenv.2023.162781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 03/06/2023] [Accepted: 03/06/2023] [Indexed: 06/18/2023]
Abstract
Arbuscular mycorrhizal fungi were recovered from soil samples from the naturally radioactive soil at the long-abandoned South Terras uranium mine in Cornwall, UK. Species of Rhizophagus, Claroideoglomus, Paraglomus, Septoglomus, and Ambispora were recovered, and pot cultures from all except Ambispora were established. Cultures were identified to species level using morphological observation and rRNA gene sequencing combined with phylogenetic analysis. These cultures were used in pot experiments designed with a compartmentalised system to assess the contribution of fungal hyphae to the accumulation of essential elements, such as copper and zinc, and non-essential elements, such as lead, arsenic, thorium, and uranium into root and shoot tissues of Plantago lanceolata. The results indicated that none of the treatments had any positive or negative impact on shoot and root biomass. However, Rhizophagus irregularis treatments showed higher accumulation of copper and zinc in shoots, while R. irregularis and Septoglomus constrictum enhanced arsenic accumulation in roots. Moreover, R. irregularis increased uranium concentration in roots and shoots of the P. lanceolata plant. This study provides useful insight into fungal-plant interactions that determine metal and radionuclide transfer from soil into the biosphere at contaminated sites such as mine workings.
Collapse
|
2
|
[Terbinafine-resistant dermatophytoses and onychomycosis due to Trichophyton rubrum]. Hautarzt 2021; 72:868-877. [PMID: 34459941 DOI: 10.1007/s00105-021-04879-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/30/2021] [Indexed: 11/28/2022]
Abstract
BACKGROUND In recent years, therapy-refractory courses of dermatophytoses have increasingly become the focus of attention. The most frequent pathogens are Trichophyton (T.) rubrum and T. mentagrophytes. In addition to local therapy, first-line treatment includes terbinafine, an allylamine antifungal agent that acts by inhibiting squalene epoxidase and thus interfering with ergosterol synthesis. In refractory cases, terbinafine resistance due to point mutation in the squalene epoxidase gene has been frequently detected. OBJECTIVES The aim is to present specific aspects in the epidemiology of dermatophytoses with terbinafine resistance and to illustrate them on the basis of four patient cases including diagnostic procedures. MATERIALS AND METHODS A review of handbook knowledge, a selective literature search, and a review of four patient cases were performed. RESULTS Detection of the terbinafine resistance was performed by in vitro testing using the breakpoint method as well as sequencing of the Trichophyton isolate and detection of the point mutation with amino acid substitution at position L393F or F397L of squalene epoxidase. CONCLUSION In refractory and recurrent dermatophytoses, terbinafine resistance should be considered, especially in T. mentagrophytes and T. rubrum, and in vitro resistance testing of the dermatophyte and point mutation analysis of squalene epoxidase (SQLE) should be performed. Therapeutically, intermittent administration of itraconazole in combination with antifungal local therapy is recommended. Nevertheless, a recurrent course is to be expected and long-term therapy with itraconazole is usually necessary.
Collapse
|
3
|
PacBio sequencing of Glomeromycota rDNA: a novel amplicon covering all widely used ribosomal barcoding regions and its applicability in taxonomy and ecology of arbuscular mycorrhizal fungi. THE NEW PHYTOLOGIST 2021; 231:490-499. [PMID: 33780549 DOI: 10.1111/nph.17372] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 03/23/2021] [Indexed: 05/02/2023]
Abstract
There is no consensus barcoding region for determination of arbuscular mycorrhizal fungal (AMF) taxa. To overcome this obstacle, we have developed an approach to sequence an AMF marker within the ribosome-encoding operon (rDNA) that covers all three widely applied variable molecular markers. Using a nested PCR approach specific to AMF, we amplified a part (c. 2.5 kb) of the rDNA spanning the majority of the small subunit rRNA (SSU) gene, the complete internal transcribed spacer (ITS) region and a part of the large subunit (LSU) rRNA gene. The PCR products were sequenced on the PacBio platform utilizing Single Molecule Real Time (SMRT) sequencing. Employing this method for selected environmental DNA samples, we were able to describe complex AMF communities consisting of various glomeromycotan lineages. We demonstrate the applicability of this new 2.5 kb approach to provide robust phylogenetic assignment of AMF lineages without known sequences from pure cultures and to consolidate information about AMF taxon distributions coming from three widely used barcoding regions into one integrative dataset.
Collapse
|
4
|
Activity of nadifloxacin and three other antimicrobial agents against Cutibacterium acnes isolated from patients with acne vulgaris. J Eur Acad Dermatol Venereol 2021; 35:e682-e684. [PMID: 34018651 PMCID: PMC8518973 DOI: 10.1111/jdv.17386] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 04/27/2021] [Accepted: 05/07/2021] [Indexed: 12/01/2022]
|
5
|
Differentially Expressed Genes Shared by Two Distinct Cytoplasmic Male Sterility (CMS) Types of Silene vulgaris Suggest the Importance of Oxidative Stress in Pollen Abortion. Cells 2020; 9:cells9122700. [PMID: 33339225 PMCID: PMC7766179 DOI: 10.3390/cells9122700] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 12/14/2020] [Indexed: 11/25/2022] Open
Abstract
Cytoplasmic male sterility (CMS), encoded by the interacting mitochondrial and nuclear genes, causes pollen abortion or non-viability. CMS is widely used in agriculture and extensively studied in crops. Much less is known about CMS in wild species. We performed a comparative transcriptomic analysis of male sterile and fertile individuals of Silene vulgaris, a model plant for the study of gynodioecy, to reveal the genes responsible for pollen abortion in this species. We used RNA-seq datasets previously employed for the analysis of mitochondrial and plastid transcriptomes of female and hermaphrodite flower buds, making it possible to compare the transcriptomes derived from three genomes in the same RNA specimen. We assembled de novo transcriptomes for two haplotypes of S. vulgaris and identified differentially expressed genes between the females and hermaphrodites, associated with stress response or pollen development. The gene for alternative oxidase was downregulated in females. The genetic pathways controlling CMS in S. vulgaris are similar to those in crops. The high number of the differentially expressed nuclear genes contrasts with the uniformity of organellar transcriptomes across genders, which suggests these pathways are evolutionarily conserved and that selective mechanisms may shield organellar transcription against changes in the cytoplasmic transcriptome.
Collapse
|
6
|
[Toxic shock syndrome due to Staphylococcus aureus in a small child, a (clinical or laboratory chemical) visual diagnosis?]. Monatsschr Kinderheilkd 2020:1-5. [PMID: 33281225 PMCID: PMC7702684 DOI: 10.1007/s00112-020-01075-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 10/31/2020] [Indexed: 11/26/2022]
Abstract
It is reported about the case of a 3-year-old girl who was admitted to hospital with high fever, vomiting, skin rash, dehydration, suspected staphyloderma and for exclusion of a severe acute respiratory syndrome coronavirus type 2-infection (SARS-CoV‑2 infection). The suspicion of a toxic shock syndrome, among other inflammatory diseases as differential diagnoses, was based on profound erythroderma and arterial hypotension. The diagnostic pathway, treatment and clinical course of this rare disease are described.
Collapse
|
7
|
Posteriores reversibles Enzephalopathiesyndrom als Differenzialdiagnose des rezidivierenden Erbrechens. Monatsschr Kinderheilkd 2020. [DOI: 10.1007/s00112-020-00999-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
8
|
What is the outcome of re-recurrent vs recurrent inguinal hernia repairs? An analysis of 16,206 patients from the Herniamed Registry. Hernia 2020; 24:811-819. [PMID: 32086633 PMCID: PMC7395905 DOI: 10.1007/s10029-020-02138-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 02/06/2020] [Indexed: 11/25/2022]
Abstract
INTRODUCTION The proportion of recurrent repairs in the total collective of inguinal hernia repairs among men is 11.3-14.3% and among women 7.0-7.4%. The rate of re-recurrences is reported to be 2.9-9.2%. To date, no case series has been published on second and ≥ third recurrences and their treatment outcomes. Only case reports are available. MATERIALS AND METHODS In an analysis of data from the Herniamed Registry the perioperative and 1-year follow-up outcomes of 16,206 distinct patients who had undergone first recurrent (n = 14,172; 87.4%), second recurrent (n = 1,583; 9.8%) or ≥ third recurrent (n = 451; 2.8%) inguinal hernia repair between September 1, 2009 and July 1, 2017 were compared. RESULTS The intraoperative complication rate for all recurrent repairs was between 1-2%. In the postoperative complications a continuous increase was observed (first recurrence: 3.97% vs second recurrence: 5.75% vs ≥ third recurrence 8.65%; p < 0.001). That applied equally to the complication-related reoperation rates (first recurrence: 1.50% vs second recurrence: 2.21% vs ≥ third recurrence 2.66; p = 0.020). Likewise, the re-recurrence rate rose significantly (first recurrence: 1.95% vs second recurrence: 2.72% vs ≥ third recurrence 3.77; p = 0.005). Similarly, the rate of pain requiring treatment rose highly significantly with an increasing number of recurrences (first recurrence: 5.21% vs second recurrence: 6.70% vs ≥ third recurrence 10.86; p = < 0.001). CONCLUSION The repair of re-recurrences in inguinal hernia is associated with increasingly more unfavorable outcomes. For the first recurrence the guidelines should definitely be noted. For a second and ≥ third recurrence diagnostic laparoscopy may help to select the best possible surgical technique.
Collapse
|
9
|
Variation in plastid genomes in the gynodioecious species Silene vulgaris. BMC PLANT BIOLOGY 2019; 19:568. [PMID: 31856730 PMCID: PMC6921581 DOI: 10.1186/s12870-019-2193-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 12/10/2019] [Indexed: 05/10/2023]
Abstract
BACKGROUND Gynodioecious species exist in two sexes - male-sterile females and hermaphrodites. Male sterility in higher plants often results from mitonuclear interaction between the CMS (cytoplasmic male sterility) gene(s) encoded by mitochondrial genome and by nuclear-encoded restorer genes. Mitochondrial and nuclear-encoded transcriptomes in females and hermaphrodites are intensively studied, but little is known about sex-specific gene expression in plastids. We have compared plastid transcriptomes between females and hermaphrodites in two haplotypes of a gynodioecious species Silene vulgaris with known CMS candidate genes. RESULTS We generated complete plastid genome sequences from five haplotypes S. vulgaris including the haplotypes KRA and KOV, for which complete mitochondrial genome sequences were already published. We constructed a phylogenetic tree based on plastid sequences of S. vulgaris. Whereas lowland S. vulgaris haplotypes including KRA and KOV clustered together, the accessions from high European mountains diverged early in the phylogram. S. vulgaris belongs among Silene species with slowly evolving plastid genomes, but we still detected 212 substitutions and 112 indels between two accessions of this species. We estimated elevated Ka/Ks in the ndhF gene, which may reflect the adaptation of S. vulgaris to high altitudes, or relaxed selection. We compared depth of coverage and editing rates between female and hermaphrodite plastid transcriptomes and found no significant differences between the two sexes. We identified 51 unique C to U editing sites in the plastid genomes of S. vulgaris, 38 of them in protein coding regions, 2 in introns, and 11 in intergenic regions. The editing site in the psbZ gene was edited only in one of two plastid genomes under study. CONCLUSIONS We revealed no significant differences between the sexes in plastid transcriptomes of two haplotypes of S. vulgaris. It suggests that gene expression of plastid genes is not affected by CMS in flower buds of S. vulgaris, although both sexes may still differ in plastid gene expression in specific tissues. We revealed the difference between the plastid transcriptomes of two S. vulgaris haplotypes in editing rate and in the coverage of several antisense transcripts. Our results document the variation in plastid genomes and transcriptomes in S. vulgaris.
Collapse
|
10
|
[Macular pucker surgery with and without delamination of the internal limiting membrane-a prospective randomized study]. Ophthalmologe 2019; 116:1038-1045. [PMID: 31300845 DOI: 10.1007/s00347-019-0936-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND There is evidence that additional internal limiting membrane (ILM) removal reduces the recurrence rate after pucker surgery with a similar functional outcome. On the other hand, morphological changes of the inner retinal layers after ILM peeling have been described. The aim of this study was to compare the long-term data after vitrectomy with and without ILM delamination in order to uncover possible differences in morphological and functional results. METHODS In a prospective study of 32 patients with idiopathic epiretinal membrane, 16 patients were randomized into each of 2 groups. Both groups underwent pars plana vitrectomy (ppV) with peeling of the epiretinal membrane. In group 1 no forced additional peeling of the ILM was performed and in group 2 the ILM or ILM residues were additionally removed after staining. The investigated parameters were visual acuity, central retinal thickness (CRT) in optical coherence tomography (OCT), metamorphopsia and surgical complications. The time points of the examinations were directly preoperative, after 1, 3 and 6 months and partly 8.4 years postoperatively. RESULTS In group 1 (n = 15) the preoperative mean visual acuity improved from 0.54 logMAR to 0.38 logMAR after 6 months postoperatively (n = 13). Of this group 6 patients could be examined in the long-term course and the visual acuity improved further to 0.32 logMAR after 8 years. The CRT decreased from 473 µm preoperatively to 235 µm in the long-term interval. In group 2 (n = 15) the mean visual acuity preoperatively was 0.47 logMAR and improved 6 months postoperatively (n = 13) to 0.38 logMAR and in the long-term examination (n = 5) to 0.1 logMAR. The CRT in this group decreased from 417 µm preoperatively to 278 µm in the long-term interval. In group 1 one recurrence occurred in the follow-up period, in group 2 none. CONCLUSION The study showed that there was no significant difference in visual acuity and CRT between the two groups neither after 6 months nor after 8 years of follow-up. The observed recurrence in the group without ILM delamination underlines the assumption that additional ILM peeling could reduce the recurrence rate.
Collapse
|
11
|
[Tinea barbae profunda due to Trichophyton mentagrophytes after journey to Thailand : Case report and review]. Hautarzt 2019; 68:639-648. [PMID: 28616693 DOI: 10.1007/s00105-017-4008-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Tinea barbae represents a very rare dermatophytosis. We report on a tinea barbae profunda following a journey to Southeast Asia. After travel to Thailand, a businessman was affected by a foudroyant proceeding abscessing infection of the upper lip and beard area. The initial therapy with oral acyclovir and oral ciprofloxacin, which later was changed to ampicillin plus sulbactam, intravenously, was unsuccessful. In a biopsy sample, histologically, with Grocott-Gomori's methenamine silver stain, fungal mycelium was apparent in the tissue. Thereupon, terbinafine 250 mg was given for 4 weeks, topically, a 1% ciclopiroxolamine-containing cream. In fungal culture, T. mentagrophytes were found to grow. Meanwhile, the patient's German wife suffered from a tinea faciei. From skin scrapings from the cheek, T. mentagrophytes was also cultivated. This zoophilic dermatophyte was identical with other zoophilic strains of T. mentagrophytes currently found in Germany, which were also acquired in Thailand. The patient had contact with Thai female sex workers who must be considered as a source of infection of the dermatophytosis. There was no animal contact, neither in Thailand, nor in Germany. The infection chain of the dermatophytosis from Thailand probably reached from a female sex worker via the here described patient to his wife in Germany. This pathway of infection has been known for 1 or 2 years, but until now, in Germany, Switzerland, and Austria exclusively via pubogenital infections (tinea genitalis profunda) due to T. mentagrophytes after journeys to Southeast Asia. For treatment, oral antifungal agents should be used, first of all terbinafine, alternatively fluconazole or itraconazole.
Collapse
|
12
|
A magnetically focused molecular beam source for deposition of spin-polarised molecular surface layers. J Chem Phys 2018; 149:164201. [PMID: 30384725 DOI: 10.1063/1.5048521] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Separating molecular spin isomers is a challenging task, with potential applications in various fields ranging from astrochemistry to magnetic resonance imaging. A new promising method for spin-isomer separation is magnetic focusing, a method which was shown to be capable of producing a molecular beam of ortho-water. Here, we present results from a modified magnetic focusing apparatus and show that it can be used to separate the spin isomers of acetylene and methane. From the measured focused profiles of the molecular beams and a numerical simulation analysis, we provide estimations for the spin purity and the significantly improved molecular flux obtained with the new setup. Finally, we discuss the spin-relaxation conditions which will be needed to apply this new source for measuring nuclear magnetic resonance signals of a single surface layer.
Collapse
|
13
|
[Trichophyton mentagrophytes-from snow leopard to man : A molecular approach for uncovering the chain of infection]. Hautarzt 2018; 69:1021-1032. [PMID: 30120492 DOI: 10.1007/s00105-018-4234-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Sources of infection for Trichophyton (T.) mentagrophytes-a zoophilic dermatophyte-comprise pet rodents (guinea pigs, mice, rabbits) and sometimes cats. Human infections due to dermatophytes after contact with zoo animals, however, are extreme rare. Four zoo keepers from Basel Zoo were diagnosed to suffer from tinea manus and tinea corporis due to T. mentagrophytes. The 22-year-old daughter of one zoo keeper was also infected with tinea corporis after having worked in the snow leopard section for one day. The strain of the index patient was confirmed by a direct uniplex-PCR-EIA and sequence analysis of the ribosomal internal transcribed spacer (ITS) region (18S rRNA, ITS1, 5.8S rRNA, ITS2, 28S rRNA) as T. mentagrophytes. Three young snow leopards from Basel Zoo were identified as the origin of the fungal skin infection. The transmission occurred due to direct contact of the zoo keepers with the young snow leopards when removing hedgehog ticks (Ixodes hexagonus). Two adult snow leopards had developed focal alopecia of the facial region which was diagnosed as dermatomycoses due to T. mentagrophytes by the zoo veterinarians. By sequence analysis, both the strains from the animals and a single strain of the index patient showed 100% accordance proving transmission of T. mentagrophytes from animals to the zoo keepers. Molecular biological identification revealed a strong relationship to a strain of T. mentagrophytes from European mink (Mustela lutreola) from Finland. Treatment of patients was started using topical ointment with azole antifungals, and oral terbinafine 250 mg once daily for 4 weeks. Both adult snow leopards and the asymptomatic young animals were treated with oral itraconazole.
Collapse
|
14
|
Chemoenzymatic Route to Oxyfunctionalized Cembranoids Facilitated by Substrate and Protein Engineering. Chemistry 2018; 24:12010-12021. [DOI: 10.1002/chem.201802250] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 06/27/2018] [Indexed: 01/19/2023]
|
15
|
|
16
|
Abstract
ZusammenfassungDas klinische Spektrum und die Erreger der Dermatophytosen unterscheiden sich deutlich zwischen Kindern und Erwachsenen. Im Gegensatz zu Erwachsenen, bei denen die Tinea pedis die häufigste Pilzinfektion der Haut darstellt, werden bei Kindern vor allem die Tinea corporis und Tinea capitis diagnostiziert. Eine neue und beunruhigende Entwicklung ist die Zunahme der Onychomykose – meist durch Trichophyton rubrum – im Kindesalter. Die Tinea capitis stellt eine diagnostische und vor allem therapeutische Herausforderung für Kinderärzte und auch Dermatologen dar. Erreger der Tinea capitis sind in Deutschland vorzugsweise zoophile Dermatophyten. An erster Stelle steht Microsporum canis, das Verhältnis verschiebt sich jedoch mehr und mehr zu den zoophilen Trichophyton-Arten, z. B. Trichophyton interdigitale (früher Trichophyton mentagrophytes). Trichophyton species von Arthroderma benhamiae ist ein neuer Erreger, der im Kindesalter wahrscheinlich mittlerweile alle anderen zoophilen Dermatophyten in Bezug auf die Häufigkeit überflügelt hat. Seltener werden Trichophyton verrucosum – Erreger der „Kälberflechte“ – und Trichophyton erinacei („Igelpilz“) isoliert. Anthropophile Erreger, wie Microsporum audouinii und Trichophyton tonsurans, müssen Anlass sein, nach der Infektionsquelle zu fahnden. Das kann ein familiärer Immigrationshintergrund sein oder auch die Infektion in einem Kampfsportverein (Tinea gladiatorum capitis et corporis).
Collapse
|
17
|
Abstract
ZusammenfassungDermatophyten verursachen oberflächliche Infektionen von Haut, Nägeln und Kopfhaut (Haarfollikeln), nicht jedoch der Schleimhaut bzw. des Körperinneren. Erreger sind meist zoophile Dermatophyten, z. B. Microsporum (M.) canis, zoophile Stämme von Trichophyton (T.) interdigale und T. verrucosum (Erreger der „Kälberflechte“). Bei Kindern und Jugendlichen ist mit einer Tinea corporis und Tinea capitis zu rechnen. Ursache einer Fuß-pilzinfektion oder Tinea pedis ist fast immer die anthropophile Dermatophyten-Art T. rubrum. Neuerdings erkranken zunehmend auch Kinder an einer Nagelmykose, fast immer hervorgerufen durch T. rubrum.Die meist zentrifugalen erythrosquamösen Läsionen einer Tinea corporis sind überwiegend trocken und hyperkeratotisch, zum mikrobiologischen Nachweis der Erreger werden Hautschuppen aus dem Randbereich der Dermatomykose entnommen (tangentiales Abschaben der Hautschuppen mittels Skalpell oder scharfem Löffel). Bei Tinea capitis sollten neben Kopfschuppen auch Haarwurzeln epiliert und untersucht werden. Die Diagnosesicherung einer Onychomykose erfordert die Entnahme von Nagelspänen mittels Skalpell oder Fräse.Die mykologische Untersuchung im Labor umfasst das sehr empfindliche fluoreszenzoptische Nativpräparat mittels Calcofluor- oder Blancophor-Lösung sowie den kulturellen Nachweis der Dermatophyten auf Spezialnährmedien. Das Ergebnis der Pilzkultur liegt erst nach 3–4 (–6) Wochen Inkubationszeit vor. Neue molekularbiologische Methoden zum Direktnachweis der Dermatophyten aus Hautschuppen, Haarwurzeln und Nagelmaterial erlauben eine schnelle und gleichzeitig sehr empfindliche und spezifische Diagnosestel-lung. In einzelnen Laboren wurde dafür eine Polymerasekettenreaktion (PCR) zum Nachweis von Dermatophyten-DNS etabliert.Die Tinea der freien Haut wird zunächst topisch antimykotisch behandelt, u. a. mit Azolen, z. B. Clotrimazol, alternativ mit Ciclopirox. Die Tinea capitis, aber auch die Tinea faciei, werden fast immer systemisch behandelt, die Auswahl des Antimykotikums hängt vom nachgewiesenen Erreger ab. Bei Tinea capitis durch Microsporum spp. ist Griseofulvin das Mittel der Wahl, Terbinafin hingegen ist bei Infektionen durch Trichophyton spp. überlegen. Daraus folgt das Konzept der sog. Spezies-spezifischen antimykotischen Behandlung der Tinea capitis.Für die systemische antimykotische Therapie der Nagelpilzinfektion im Kindesalter liegen bisher keine verbindlichen Empfehlungen vor. Die meisten Erfahrungen bei Kindern und Jugendlichen mit Onychomykose existieren bisher zum Einsatz von Terbinafin bzw. Itraconazol.
Collapse
|
18
|
Measurement of the ν μ energy spectrum with IceCube-79: IceCube Collaboration. THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS 2017; 77:692. [PMID: 31997925 PMCID: PMC6956919 DOI: 10.1140/epjc/s10052-017-5261-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 09/25/2017] [Indexed: 06/09/2023]
Abstract
IceCube is a neutrino observatory deployed in the glacial ice at the geographic South Pole. The ν μ energy unfolding described in this paper is based on data taken with IceCube in its 79-string configuration. A sample of muon neutrino charged-current interactions with a purity of 99.5% was selected by means of a multivariate classification process based on machine learning. The subsequent unfolding was performed using the software Truee. The resulting spectrum covers an E ν -range of more than four orders of magnitude from 125 GeV to 3.2 PeV. Compared to the Honda atmospheric neutrino flux model, the energy spectrum shows an excess of more than 1.9 σ in four adjacent bins for neutrino energies E ν ≥ 177.8 TeV . The obtained spectrum is fully compatible with previous measurements of the atmospheric neutrino flux and recent IceCube measurements of a flux of high-energy astrophysical neutrinos.
Collapse
|
19
|
Trichophyton rubrum-Syndrom und Tinea incognita unter immunsuppressiver Behandlung mit Leflunomid und Fumarsäureestern bei Patienten mit rheumatoider Arthritis und Psoriasis vulgaris. AKTUELLE DERMATOLOGIE 2017. [DOI: 10.1055/s-0043-112665] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
ZusammenfassungEin 70-jähriger Patient mit rheumatoider Arthritis (Anti-CCP-Antikörper positiv), Nikotinabusus und Arteriosklerose wurde immunsuppressiv mit Leflunomid 20 mg und Prednisolon 50 mg täglich behandelt. Am Körperstamm traten großflächige, ekzematisierte, randbetonte, zentrifugal wachsende erythrosquamöse Läsionen auf. Die Haut der rechten Hand und beider Füße war trocken, schuppend und atrophisch. Außerdem bestanden gelbbraune Onychodystrophien aller Fingernägel der rechten Hand sowie aller Zehennägel. Das Blankophor®-Präparat aus Hautschuppen war positiv, kulturell und mit PCR ließ sich Trichophyton (T.) rubrum nachweisen. Die ausgeprägte Tinea corporis wurde mit einer Antimykotika- und Glukokortikoid-haltigen Creme behandelt, wegen der Tinea unguium kam Terbinafin zur Anwendung. Ein 68-jähriger Psoriatiker erhielt bereits seit 1979 Fumarsäureester zur systemischen antipsoriatischen Therapie. Seit einigen Monaten entwickelten sich an Flanken, Rücken, gluteal, an den Waden, prätibial und an den Oberschenkeln blass-rote erythrosquamöse Plaques im Sinne einer Tinea corporis incognita. Das Nativpräparat war positiv, kulturell und mit PCR gelang aus insgesamt 6 Lokalisationen der Nachweis von T. rubrum. Da eine systemische antimykotische Behandlung abgelehnt wurde, kam Terbinafin-Creme im Wechsel mit Clotrimazol- + Betamethason-Creme zur Anwendung.Die großflächige und generalisierte Tinea corporis mit Onychomykose erfüllte bei beiden Patienten die Kriterien eines sog. T. rubrum-Syndroms. Dieses, aber auch die Tinea incognita, entwickeln sich in der Regel infolge einer Autoinokulation von einer vorbestehenden Tinea pedis et unguium. Disponierender Faktor für das T. rubrum-Syndrom, aber auch für die Tinea incognita, ist nicht selten eine immunsupprimierende Therapie, hier durch Glukokortikoide, Leflunomid sowie Fumarsäureester.
Collapse
|
20
|
[Non-viral sexually transmitted infections - Epidemiology, clinical manifestations, diagnostics and therapy : Part 1: Gonococci]. DER HAUTARZT 2017; 68:43-49. [PMID: 27981386 DOI: 10.1007/s00105-016-3905-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Approximately 1 million people are infected per day worldwide by one or more sexually transmitted infections (STI) as estimated by the World Health Organization (WHO). Gonorrhoea represents an almost exclusively sexually transmitted infection, which predominantly affects mucous membranes of the genitourinary tract. Extragenital localization of infections is also possible, e. g. in the anorectal region. Currently, only syphilis and human immunodeficiency virus (HIV) are notifiable diseases according to the Infection Protection Act in Germany. In Saxony, an extended registration ordinance according to the German Infection Protection Act is in force, which means that besides syphilis the laboratory detection of Neisseria gonorrhoeae, Chlamydia trachomatis and genital mycoplasms are also notifiable infections. In particular, beginning in 2009 in Saxony a spectacular increase of registered infections due to N. gonorrhoeae was observed and in 2015 altogether 824 infections due to N. gonorrhoeae were reported. Alarming is the increase in resistance of N. gonorrhoeae against penicillin, doxycycline, ciprofloxacin and recently also against azithromycin and third generation cephalosporins. The so-called superbug of N. gonorrhoeae, which originated in Japan with multidrug resistance against most of the currently available oral antibiotics, has now arrived in Europe. Intramuscular or intravenous injection of ceftriaxone plus oral azithromycin, each given as single dose is the standard therapy for gonorrhoea.
Collapse
|
21
|
Search for high-energy neutrinos from gravitational wave event GW151226 and candidate LVT151012 with ANTARES and IceCube. Int J Clin Exp Med 2017. [DOI: 10.1103/physrevd.96.022005] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
22
|
Abstract
Moulds or non-dermatophyte moulds (NDM) are being increasingly isolated as causative agent of onychomycoses. Known causes of a NDM-OM are Scopulariopsis brevicaulis, Fusarium, Aspergillus, Acremonium, Neoscytalidium dimidiatum, Arthrographis kalrae, and Chaetomium. In this article, 5 patients with suspected nail infection due to Onychocola canadensis are reported for the first time in Germany. Systemic antifungal agents are not considered to be effective in NDM onychomycosis. In individual cases, however, terbinafine seems to be effective in Onychocola canadensis infection of the nails. Treatment of choice represents, however, nontraumatic nail avulsion using 40 % urea ointment followed by antifungal nail lacquer with ciclopirox olamine or amorolfine.
Collapse
|
23
|
Communities of arbuscular mycorrhizal fungi under Picconia azorica in native forests of Azores. Symbiosis 2017. [DOI: 10.1007/s13199-017-0487-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
24
|
Plant Communities Rather than Soil Properties Structure Arbuscular Mycorrhizal Fungal Communities along Primary Succession on a Mine Spoil. Front Microbiol 2017; 8:719. [PMID: 28473828 PMCID: PMC5397529 DOI: 10.3389/fmicb.2017.00719] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 04/06/2017] [Indexed: 02/01/2023] Open
Abstract
Arbuscular mycorrhizal fungal (AMF) community assembly during primary succession has so far received little attention. It remains therefore unclear, which of the factors, driving AMF community composition, are important during ecosystem development. We addressed this question on a large spoil heap, which provides a mosaic of sites in different successional stages under different managements. We selected 24 sites of c. 12, 20, 30, or 50 years in age, including sites with spontaneously developing vegetation and sites reclaimed by alder plantations. On each site, we sampled twice a year roots of the perennial rhizomatous grass Calamagrostis epigejos (Poaceae) to determine AMF root colonization and diversity (using 454-sequencing), determined the soil chemical properties and composition of plant communities. AMF taxa richness was unaffected by site age, but AMF composition variation increased along the chronosequences. AMF communities were unaffected by soil chemistry, but related to the composition of neighboring plant communities of the sampled C. epigejos plants. In contrast, the plant communities of the sites were more distinctively structured than the AMF communities along the four successional stages. We conclude that AMF and plant community successions respond to different factors. AMF communities seem to be influenced by biotic rather than by abiotic factors and to diverge with successional age.
Collapse
|
25
|
Tinea genitalis profunda durch Trichophyton mentagrophytes nach Ägypten-Reise. AKTUELLE DERMATOLOGIE 2017. [DOI: 10.1055/s-0043-106149] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
26
|
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.
Collapse
|
27
|
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.
Collapse
|
28
|
|
29
|
[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.
Collapse
|
30
|
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}.
Collapse
|
31
|
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]
|
32
|
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.
Collapse
|
33
|
|
34
|
|
35
|
|
36
|
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.
Collapse
|
37
|
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
|
38
|
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
|
39
|
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
|
40
|
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.
Collapse
|
41
|
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.
Collapse
|
42
|
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.
Collapse
|
43
|
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.
Collapse
|
44
|
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)°.
Collapse
|
45
|
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.
Collapse
|
46
|
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.
Collapse
|
47
|
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.
Collapse
|
48
|
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.
Collapse
|
49
|
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.
Collapse
|
50
|
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.
Collapse
|