bluuebunny/crossref_metadata_2025 huggingface dataset:
Exophiala jeanselmei keratitis
Authors: Al‐Hedaithy S. S. A. , Al‐Kaff A. S.
Published: July 2010

Summary. We present the case of a 42‐year‐old Saudi male with a fungal corneal abscess in his left eye. The aetioiogical agent was found to be the dematiaceous fungus Exophiala jeanselmei. The patient was treated with topical natamycin, miconazole, and also amphotericin B. During the course of the infection corneal perforation occurred which was treated with cyanocrylate glue. Secondary glaucoma resulted from peripheral anterior synechia which necessitated trabeculectomy. At the end of the course the infection was successfully eradicated, the complications were cured, and vision improved from counting fingers in front of the face at presentation to 20/80. There was no recurrence of the infection in a follow‐up period of 2 years.

Zusammenfassung. Es wird ein 42 Jahre alter saudiarabischer Mann mit pilzbedingtem Hornhautabszeß im linken Auge vorgestellt. Als Erreger wurde der Schwärzepilz Exophiala jeanselmei nachgewiesen. Der Patient wurde topisch mit Natamycin, Miconazol und auch mit Amphotericin B behandelt. Während des Infektionsverlaufs trat eine Hornhaut‐Perforation auf, die mit Cyanocrylat‐Leim behandelt wurde. Aus der peripheren Synechie vorn entwickeite sich ein sekundäres Glaukom, das eine Trabekulektomie erforderlich machte. Am Ende des Krankheitsverlaufs waren die Infektion beherrscht, die Komplikationen ausgeheilt, und der Visus verbesserte sich von der Wahrnehmung der Handbewegung bis auf 20/80. In einem Nachbeobachtungszeitraum von zwei Jahren kam es zu keinem Rückfall.
Control of Candida albicans vaginitis in mice by short‐duration butoconazole treatment in situ
Authors: Valentin A. , Bernard Christine , Mallié Michèle , Huerre M. , Bastide J. M.
Published: July 2010

Summary. A short‐duration treatment for can‐didal vaginitis applying butoconazole in situ was tested in an experimental mouse model. One week after artificial induction of an oestrus state (by oestradiol benzoate injection), mice were inoculated intravaginally with 1.5 × 107 blastospores of Candida albicans (strain ATCC 44858). Treatment consisted of butoconazole solutions (1%, 2.5% and 5%) administered intravaginally. The development of the infection was monitored daily for 12 days and then three times a week by local samples plated on BiGGY agar. In parallel, twice a week, the vaginas of three mice in each group (control and treated groups) were isolated in order to estimate organ invasion by C. albicans. This was assessed by anatomopathological studies on a fixed and stained part of the organ and by serial dilutions of a homogenate of the remaining part plated on Sabouraud glucose chloramphenicol agar. After a 48‐h incubation period the number of colony forming units per gram of tissue was counted. For each treatment, a remission of 10–15 days was observed, but was followed by a recurrence for the lower dose of butoconazole; only the higher butoconazole concentrations tested (2.5% and 5%) gave an apparent full cure for most of the mice tested. The use of the mouse model of candidal vaginitis confirms that short‐duration treatment is possible when elevated doses of butoconazole are used.

Zusammenfassung. An, einem experimentellen Mausmodell wurde eine Butoconazol‐Kurzzeitbehandlung in situ erprobt. Eine Woche nach kunstlicher Induktion des Östrus durch Östradiolbenzoat‐Injektion wurden den Mäusen intravaginal 1.5 × 107Candida albicans‐Blastosporen (ATCC 44858) inokuliert. Die Behandlung bestand in intravaginaler Anwendung von 1%, 2.5% und 5% iger Butoconazol‐Lösung. Die Entwicklung der Infektion wurde 12‐d lang täglich und danach dreimal wöchentlich durch Ausimpfen lokal gewonnenen Untersuchungsmaterials auf BiGGY‐Agar kontrolliert. Parallel wurden zweimal wöchentlich die Vaginen von je drei Mäusen jeder Gruppe (Kontrollen und behandelte Gruppen) gewonnen, teils fixiert, gefärbt und die Organinvasion durch C. albicans histopathologisch untersucht; der Rest der Vaginen wurde homogenisiert, in Aliquots auf Sabouraud‐Glucose‐Chloramphenicol‐Agar verimpft und nach 48‐h Bebrütung über die Koloniezählung die Keimzahl pro Gramm Gewebe bestimmt. Bei jeder Behand‐lungsart trat in den ersten 10–15 d Besserung ein, gefolgt jedoch von Rezidiven bei der niedrigeren Butoconazol‐Konzentration; nur die höheren Butoconazol‐Konzentrationen (2.5% und 5%) führten bei der Mehrzahl der Mäuse zur vollen Ausheilung. Die Untersuchungsergebnisse lassen erkennen, daß eine erfolgreiche Kurzzeitbehand‐lung mit Butoconazol möglich ist, wenn höhere Dosen eingesetzt werden.
Terbinafine induces the PMNL priming effect and enhances in vitro PMNL fungicidal activity against Candida albicans blastospores
Authors: Barbareschi M. , Vago T. , Colombo D. , Bevilacqua M.
Published: July 2010

Summary. Terbinafine, a new antifungal drug of the allylamine category; has been shown not to interfere with some polymorphonuclear leucocyte (PMNL) functions such as chemotaxis and chemi‐luminescence. The aim of the present study was to elucidate the effects of terbinafine on PMNL respiratory burst activation and killing of Candida albicans blastospores by PMNLs at the biochemical and ultrastructural level by means of scanning electron microscopy (SEM). Terbinafine is shown to enhance the respiratory burst and superoxide anion release in human PMNLs stimulated by phorbol esters or chemotactic peptides, and to have a priming effect on PMNL functions. Moreover, in our experiments we found that terbinafine does not interfere with PMNL killing of C. albicans blastospores but, in fact, at the concentration found in tissues after oral administration, slightly increases it. As PMNLs play a key role in the early stages of fungal infections we suggest that in vivo terbinafine induces priming of PMNLs, and that this effect is related to enhanced candida‐cidal activity independent of direct drug damage to fungal particles.

Zusammenfassung. Terbinafin, ein Antimyze‐tikum der Allylamin‐Gruppe, hat keinen Einfluß auf Chemotaxis und Chemolumuneszenz poly‐morphkerniger Granulozyten (PMNL). Ziel der vorliegenden Studie war, die Terbinafin‐Wirk‐ungen auf die Respiratory‐Burst‐Aktivität von PMNL und deren Abtötungsfahigkeit gegenüber Candida albicans‐Blastosporen biochemisch und ultrastrukturell mittels Rasterelektronenmikrosko‐pie zu untersuchen. Terbinafin steigert die Respiratory‐Burst‐Aktivität und die Freisetzung von Peroxid‐Anionen in PMNL, die mit Phorbolestern oder chemotaktischen Peptiden zur Erzielung eines Primingeffektes stimuliert waren. Hierbei wurde kein Einfluß auf die Abtötungsfähigkeit der PMNL fur C. albicans‐Blastosporen beobachtet; Terbinafin in der GröBenordnung von Gewebskonzentrationen erhöht jedoch diese Abtötungsfähigkeit geringgradig. Da PMNL im Frühstadium von Pilzinfektionen eine Schlüsselrolle spielen, wird gefolgert, daß Terbinafin auch in vivo einen sol‐chen Primingeffekt bewirkt, der, zusätzlich und unabhangig von der Direktschädigung der Pilz‐zelle, zu erhöhter candidazider PMNL‐Aktivität führt.
Subcutaneous infection due to Curvularia species
Authors: Subramanyam V. R. , Rath C. C. , Mishra Minati , Chhotrai G. P.
Published: July 2010

Summary. A Curvularia species was isolated from a chronic ulcer on the lower limb of a 2I‐year‐old man. The histopathological findings supported the mycological diagnosis. An enzyme‐linked immuno‐sorbent assay (ELISA) was performed using a crude soluble fungal antigen. The patient's serum contained significantly more antibodies than 10 sera from control subjects (P<0.05, t‐test).

Zusammenfassung. Curnularia spec. wurde aus einem chronischen Ulkus am unteren Glied eines 21‐jährigen Mannes isoliert. Die Histopathologie stiitzt die mykologische Diagnose. Ein ELISA wurde auf der Basis eines löslichen Rohantigens zum Antikörpernachweis entwickelt. Das Patien‐tenserum zeigte einen signifikant höheren Anti‐körpertiter im Vergleich zu Seren von zehn Kontrollpersonen (P<0.05 im t‐Test)
Fluconazole in the treatment of Candida prosthetic valve endocarditis
Authors: Wallbridge D. R. , McCartney A. Christine , Richardson M. D.
Published: July 2010

Summary. We report further success with fluconazole in the treatment of prosthetic valve endocarditis due to Candida parapsilosis.

Zusammenfassung. Wir berichten über einen weiteren Erfolg in der Fluconazol‐Behandlung einer Candida parapsilosis‐bedingten Endocarditis bei Mitralklappen‐Prothese.
Karyotypes of oval cell forms of Malassezia furfur
Authors: Howell Susan A. , Quin Christine , Midgley Gillian
Published: July 2010

Summary. Karyotypes of different morphological forms of oval cell types of Malassezia furfur (previously called Pityrosporum ovule) were examined by pulsed‐field gel electrophoresis. All strains produced patterns containing seven chromosome bands. These patterns could be separated into three distinct groups, which appeared to correlate with groups based on morphology.

Zusammenfassung. Karyotypen morpholo‐gisch unterschiedlicher Formen ovaler Zelltypen von Malassezia furfir (früher Pityrosporum ovale) wurden pulsfeld‐gelelektrophoretisch untersucht. Alle Stämme produzierten Bandenmuster mit sieben Chromosomenbanden. Diese Muster konn‐ten in drei unterschiedliche Gruppen aufgeteilt werden, die den morphologischen Gruppierungskategorien entsprachen.
In vitro susceptibility of public indoor swimming pool fungi to three disinfectants
Authors: Bobichon H. , Dufour‐Morfaux F. , Pitort V.
Published: July 2010

Summary. The floors of indoor swimming pools are contaminated by yeasts, dermatophytes and other saprophytic species. Previous epidemiolog‐ical studies have revealed that the fungi persist even after cleaning. Three disinfectants were tested in vitro against fungi standard isolated from swimming pool floors. Minimum inhibitory concentration (MIC) tests and AFNOR standard T72–201 were carried out. Adilon and Decalcite, commonly used in swimming pools, were ineffective against most of the fungi, while Nobactel, recommended elsewhere, was particularly effective against the studied fungi. In addition to the necessary technical modifications of the methods, this study highlights the need to choose effective anti‐fungal compounds and to alternate cleaning products to minimize acquired resistance.

Zusammenfassung. Die Fußböden öffentlicher Hallenbäder sind kontaminiert durch Hefen, Dermatophyten und weiterhin durch saprophytische Pilze. Frühere epidemiologische Studien belegten die Persistenz von Pilzen auch nach Fußboden‐Pflegemaßnahmen. Drei Desinfektionsmittel wurden in vitro in ihrer Wirksamkeit auf Pilzisolate von Schwimmhallen‐Fußböden untersucht. Es wurden MHK‐Bestimmungen und Untersuchun‐gen gemäß der Norm AFNOR T 72–201 durchge‐führt. Adilon und Decalcite, verbreitet in Schwimmhallen in Gebrauch, waren gegen die meisten Pilze unwirksam, während Nobactel, für andere Zwecke empfohlen, besonders wirksam gegen die Testpilze war. Die Studie zeigt, daß neben technischen Modifikationen es notwendig ist, mit den Reinigungsmitteln abzuwechseln, um erworbene Resistenz gering zu halten, sowie pilzwirksame Substanzen zu verwenden.
Im vitro antifungal activity of essential oils obtained from officinal plants against dermatophytes
Authors: Lima E. O. , Gompertz O. F. , Giesbrecht A. M. , Paulo M. Q.
Published: July 2010

Summary. Thirteen essential oils were isolated from officinal plants and tested in vitro against dermatophyte strains isolated from patients with dermatophytosis. Of the tested oils, those obtained from Cinnamomum zeylanicum, Ocimum gratissimum, Cymbopogon citratus, Eugenia uniflora and Alpinia speciosa were found to be the most active, inhibiting 80% of the dermatophyte strains tested and producing inhibition zones more than 10 mm in diameter.

Zusammenfassung. Dreizehn ätherische Öle wurden aus Heilpflanzen isoliert und in vitro gegen Dermatophytenstämme getestet, die von Dermatophytose‐Patienten isoliert worden waren. Von den untersuchten Ölen erwiesen sich die von Cinnamomum zeylanicum, Ocimum gratissi‐mum, Cymbopogon citratus, Eugenia uniflora und Alpinia speciosa gewonnenen als die aktivsten. Sie hemmten 80% der eingesetzten Dermatophytenstämme und bildeten Hemmzonen von mehr als 10 mm Durchmesser aus.
Pathogenicity of strains of the black yeast Exophiala (Wangiella) dermatitidis: an evaluation based on polymerase chain reaction
Authors: Uijthof J. M. J. , de Hoog G. S. , de Cock A. W. A. M. , Takeo K. , Nishimura K.
Published: July 2010

Summary. Strains of Exophiala dermatitidis, mainly originating from patients with systemic neurotropic mycosis in Asia and from the lungs of patients with cystic fibrosis (CF) in Europe, were analysed by ribotyping of the small subunit rDNA and by random amplification of polymorphic DNA (RAPD). A characteristic banding pattern for the species was found after restriction analysis of amplified fragments V9 and ITS4. The small subunit rDNA gene of five strains was about 1800 base pairs (bp) long, while in 16 strains its length was about 3000 bp Using RAPD, seven populations could be distinguished. European CF strains as well as Asian strains from systemic mycoses are mainly distributed over two populations, one of which contained both CF strains and a systemic strain. It is concluded that the two clinical pictures are caused by genetically similar strains. The differences in pathogenicity may be explained by immunological differences in the hosts or by differences in exposure to the fungal propagules.

Zusammenfassung. Ribotypisierung von SS rDNA und RAPD wurde an Stämmen von Exophiala dermatitidis, darunter Isolaten aus neurotropen Mykosen in Asien und Isolaten aus Lungen von Patienten mit zystischer Fibrose in Europa, durchgeführt. Das Bandenmuster amplifizierter und verdauter V9‐ITS4 Fragmente erwies sich als konstant und artspezifisch. Das SS rDNA Gen von 5 Stämmen war 1800 Basenpaare lang, während bei 16 Stämmen zusätlich Insertionen von etwa 1200 Basenpaaren nachgewiesen wurden. Mit RAPD wurden 7 Populationen unterschieden. Die europäischen CF‐Stämme ließen sich in zwei Populationen aufgliedern; die Stämme von systemischen Mykosen aus Asien gehörten ebenfalls zwei Populationen an. Dabei umfaßte die umfangreichste Population sowohl CF‐Stämme als auch einen systemischen Stamm, nebst Isolaten anderer Herkunft. Dies läßt den Schluß zu, daß genetisch ähnliche Stämme beide Krankheitsbilder verursachen können. Die Pathogenitätsunterschiede lassen sich möglicherweise durch immunologische Unterschiede der Wirte oder durch regionale Expositionsunterschiede für die Pilze erklären.
White piedra and Trichosporon species in equatorial Africa. III. Identification of Trichosporon species by slide agglutination test
Authors: Douchet C. , Thérizol‐Ferly M. , Kombila M. , Duong T. H. , de Diaz M. Gomez , Barrabes A. , Richard‐Lenoble D.
Published: July 2010

Summary. Fifty‐two Trichosporon strains isolated from Gabonese female patients 15–60 years, were studied. The identity of these strains was established by two different methods: the method proposed by Guého et al. (1992), based on mycological criteria, and a slide agglutination method performed with monospecific antisera prepared in our laboratory. The final results show a perfect correlation between the two methods, which allowed us to identify 25 strains of T. mucoides, 21 strains of T. inkin and seven strains of T. asahii. The results of the agglutination tests performed with 24‐h‐old subcultures grown on Sabouraud glucose agar are available in less than 15 mins. In the light of these results, it appears that this method, which is rapid and easy to perform and reproduce, may readily be used in hospital laboratories. In addition, this method allowed us to verify the presence of antigens common to the genera Cryptococcus and Trichosporon, which were easily shown by the use of crude sera. The fact that the anti‐Triehosporon monospecific sera lose their capacity to agglutinate Cryptococcus neoformans proves their high specificity.

Zusammenfassung. Die Identität von 52 Trichosporon‐Stämmen, isoliert von gabunesischen Frauen im Alter zwischen 15 und 60 Jahren. wurden nach zwei unterschiedlichen Methoden identifiziert: 1. Nach der Methode von Guého et al. 1992, die auf mykologischen Kriterien beruht. und 2. mittels einer Objektträger‐Agglutinations‐methode unter Verwendung monospezifscher, in unserem Labor hergestellter Antiseren. Die Ergebnisse belegen eine vollkommene Korrelation zwischen beiden Methoden, die es erlaubte, 25 Stämme von T. mucoides, 21 Stämme von T. inkin und 7 Stämme von T. asahii zu identifizieren. Die Agglutinationsreaktionen wurden mil 24 h alten Subkulturen auf Sabouraud‐Glucose‐Agar durchgeführt; ihre Ergebnisse waren in weniger als 15 Minuten verfügbar. Auf dem Hintergrund dieser Befunde wird diese Methode als schnell, leicht durchführbar und sicher reproduzierbar für die allgemeine Anwendung in Krankenhauslaboratorien empfohlen. In dieser Studie war auch der Besitz gemeinsamer Antigene bei den Gattungen Cryptococcus und Trichosporon nachweisbar, wenn Rohseren verwendet wurden. Der Nachweis, daß monospezifische Anti‐Trichosporon‐Seren die Fähigkeit verlieren, Cryptococcus neoformans zu agglutinieren, belegt ihre hohe Spezifität.
Ecology and physiology of the emerging opportunistic fungi Pseudallescheria boydii and Scedosporium prolificans
Authors: de Hoog G. S. , Marvin‐Sikkema Femke D. , Lahpoor Greetje A. , Gottschall J. C. , Prins R. A. , Guého Eveline
Published: July 2010

Summary. Nutritionally physiological patterns of Pseudallescheria boydii (Microascaceae) and the related species Scedosporium prolificans were established. Differences between the two species were found in assimilation of sucrose, ribitol, xylitol and L‐arabinitol. In contrast, no physiological distinction could be made between the three intraspecific variants of P. boydii which have been recognized on the basis of nDNA/DNA homology data and of morphological and clinical differences. Some potential virulence factors were studied in the fungi mentioned above and in some related anamorphs. All species were capable of anaerobic growth, but differed in their temperature relations.

Zusammenfassung. Assimilations‐Muster von Pseudallescheria boydii (Microascaceae) und der verwandten Art Scedosporium prolificans wurden untersucht. Dabei wurden Art‐Unterschiede in der Assimilation von Saccharose, Ribitol, Xylitol und L‐Arabinitol festgestellt. Im Gegensatz dazu wurden keine physiologischen Unterschiede zwischen den drei Varianten innerhalb der Art P. boydii nachgewiesen. Damit lassen sich die bisher verwendeten Merkmalsunterschiede, bzw. nDNA/DNA Homologie‐Werte sowie morphologische und klinische Characteristika, nicht bestätigen. Einige mögliche Virulenz‐Faktoren bei den oben beschriebenen sowie auch bei einigen verwandten Arten, wurden untersucht. Alle Arten erwiesen sich im gleichen Maß zum anaeroben Wachstum befähigt, unterscheiden sich aber in ihrem Temperaturverhalten.
Polymerase chain reaction‐based detection of dermatophyte DNA with a fungus‐specific primer system
Authors: Bock M. , Maiwald M. , Kappe R. , Nickel P. , Näher H.
Published: July 2010

Summary. There is significant clinical interest in primers which are specific for fungi and do not hybridize to DNA of other eukaryotes or prokaryotes. Such primers would allow specific amplification of fungal DNA from human tissue samples containing fungi. Fungal identification to the species level could follow by direct sequencing or restriction analysis. Several previously described primer systems cross‐react with DNA of plants and animals.

We have designed a primer system that amplifies a fragment of the gene coding for the small ribosomal subunit 18S rRNA. Database searches and sequence analyses were performed using the HUSAR (Heidelberg Unix Sequence Analysis Resources) computer system at the German Cancer Research Centre, Heidelberg, Germany. Primers TR1 (5′‐GTTTCTAGGACCGCCG‐TA) and TR2 (5′‐CTCAAACTTCCATCGAC‐TTG) bind to sequences which are homologous within the fungi, but differ from corresponding DNA fragments of plants and animals. The amplified fragment is 581 base pairs in length and contains variable, and therefore species‐specific, regions.

The DNA of Trichophyton rubrum, Trichophyton mentagrophytes, Trichophyton verrucosum, Trichophyton terrestre, Microsporum canis, Microsporum gypseum and Epidermophyton floccosum and of several yeast species was amplified by the primers, but not the DNA from 42 normal human skin samples. Furthermore, other DNA preparations from plants and animals, including those from radish, cabbage, wheat and mouse, did not show amplification reactions.

Zusammenfassung. Es besteht großes klinisches Interesse an Primern, die für Pilze spezifisch sind und nicht mit DNA von anderen Eukaryonten oder Prokaryonten hybridisieren. Solche Primer würden die spezifische Amplifikation von Pilz‐DNA aus menschlichen Gewebeproben, die Pilze enthalten, erlauben. Die Pilzidentifizierung bis zur Speziesebene könnte folgen—mittels direkter Sequenzierung oder Restriktionsanalyse. Mehrere früher beschriebene Primersysteme zeigten Kreuzreaktionen mit DNA von Pflanzen und/oder Tieren.

Wir entwarfen ein Primersystem, welches ein Fragment des Gens amplifiziert, das für die kleine ribosomale Untereinheit (18S rRNA) kodiert. Datenbanksuche und Sequenzanalysen wurden mit dem HUSAR (Heidelberg Unix Sequence Analysis Resources)‐Computersystem des Deutschen Krebsforschungszentrums (DKFZ), Heidelberg, Bundesrepublik Deutschland, durchgeführt. Die Primer TR1 (5′‐GTTTCTAGGACCGCC‐GTA) und TR2 (5′‐CTCAAACTTCCATCGAC‐TTG) binden an Sequenzen, die innerhalb der Pilze homolog sind, sich jedoch von korrespondierenden DNA‐Abschnitten bei Pflanzen und Tieren unterscheiden. Das amplifizierte Fragment ist 581 Basenpaare lang und enthält variable, und daher spezies‐spezifische Regionen.
Partial purification and characterization of a 235000Mr extracellular proteinase from Trichophyton rubrum
Authors: Lambkin Imelda , Hamilton A. J. , Hay R. J.
Published: July 2010

Summary. An extracellular proteinase has been partially purified from culture filtrates of Trichophyton rubrum by ultrafiltration, isoelectric focusing and gel filtration chromatography. The enzyme has a non‐reduced molecular weight of 235000 by substrate SDS‐PAGE. It has a pH optimum of 8.5 using azocasein and azoalbumin as substrates and a pI of 3.6‐3.8. The metalloproteinase inhibitors EDTA and 1,10‐phenanthroline, together with the chymotrypsin inhibitor chymostatin, strongly inhibited its activity. The serine proteinase inhibitors phenylmethanesulphonyl fluoride and diisopropylfluorophosphate showed weak inhibitory activity. The proteinase exhibited broad substrate activity against azocoll, azoalbumin, azocasein, laminin and fibronectin. It exhibited weak activity against elastin and keratin. Observations on the occurrence of this proteinase together with previously described lower molecular weight proteinases suggests that the former is the first to appear in minimal medium cultures. Freeze/thaw cycling of the partially purified 235000Mr proteinase was found to generate low molecular weight proteinases, particularly at 53000, 27000 and 25000Mr, indicating that the latter may originate from the larger molecule.

Zusammenfassung. Aus Kulturfiltraten von Trichophyton rubrum wurde durch Ultrafiltration, isoelektrische Fokussierung und Gelfiltrationschromatographie eine extrazelluläre Proteinase partiell gereinigt. Das Enzym hat nicht reduziert in der Substrat‐SDS‐PAGE ein Molekulargewicht von 235000. Bei Verwendung von Azocasein und Azoalbumin wurde ein pH‐Optimum von 8,5 bestimmt; der pI liegt bei 3.6‐3.8. Die Enzymaktivität wurde durch die Metalloproteinase‐Hemmer EDTA und 1,10‐Phenanthrolin zusammen mit dem Chymotrypsin‐Hemmer Chymostatin stark gehemmt. Die Serinproteinasen‐Hemmer Phenylmethansulfonylfluorid und Diisopropylfluorphosphat zeigten nur schwache Hemmwirkung. Die Proteinase zeigte breite Substrataktivität gegen Azocoll, Azoalbumin, Azocasein, Laminin und Fibronectin; sie zeigte schwache Aktivität gegen Elastin und Keratin. Im Vergleich mit früher beschriebenen niedrigmolekular‐gewichtigen Proteinasen scheint das hier vorgestellte Enzym in Minimalmedium‐Kulturen früher aufzutreten. Wiederholtes Frieren‐Auftauen der partiell gereinigten 235000Mr‐Proteinase führte zum Auftreten niedrigmolekulargewichtiger Proteinasen insbesondere von 53000, 27000 und 25000Mr, was darauf hindeutet, daß die letzteren vom größeren Molekül abgespalten werden.
InvasiveTrichosporon beigeliiinfection in immunosuppressed rats
Authors: Dörlemann A. , Listemann H. , Iglauer F.
Published: July 2010

Summary.Fulminant systemic mycoses were seen as complications in rats undergoing drug trials for the treatment ofPneumocystis cariniipneumonia. Rats were immunosuppressed with corticosteroids and by feeding with a low‐protein diet. Homogenized pulmonary tissue from a rat with pneumocystosis was inoculated transtracheally. Secondary invasive mycosis was found in 56 of 59 rats examined.Trichosporon beigeliiwas identified as the causative agent in the majority of cases. After examining possible sources of infection, aPneumocystisinoculum contaminated with fungi was found to be the obvious source.T. beigeliiinfections are becoming increasingly significant in immunocompromised human patients. The need for suitable and reproducible animal models is therefore also increasing. Observations described in this paper may help in the further development of such models.

Zusammenfassung.In einem Versuchsansatz, in dem am Rattenmodell derPneumocystis carinii‐Pneumonie neue Medikamente getestet werden sollten, traten als unerwartete Komplikationen fulminant verlaufende Systemmykosen auf. Bei 56 von 59 untersuchten Ratten, die durch Kortisonbehandlung und mittels einer proteinarmen Diät immunsupprimiert wurden und denen transtracheal ein Lungenhomogenat von einer Pneumocystosis‐erkrankten Ratte inokuliert worden war, bildeten sich sekundär invasive Mykosen aus. Überwiegend konnteTrichosporon beigeliials verursachender Keim identifiziert werden. Wie die Überprüfung möglicher Infektionsquellen ergab, waren die Pilze offensichtlich durch kontaminiertes Inokulum übertragen worden.T. beigelii‐Infektionen gewinnen bei Patienten mit Abwehrschwächen zunehmend an Bedeutung und folglich auch der Bedarf an geeigneten und reproduzierbaren Tiermodellen, für deren Entwicklung die hier beschriebenen Beobachtungen eine weiterführende Chance bieten.
Dielectric Properties of Microstructure‐Controlled Ba2Ti9O20 Resonators
Authors: Lin Wen‐Yi , Speyer Robert F.
Published: July 2010

Thermal schedules for sintering ZrO2‐ and SnO2‐doped Ba2Ti9O20 resonators to minimum porosity were developed using a shrinkage‐rate‐controlled dilatometer. Efficient sintering schedules were formulated that circumvented pore formation via grain‐boundary/triple‐point liquid‐phase volatilization. A densification rate (0.5%/min) for the early stages of sintering, which minimized intragranular porosity, was chosen. For the later stages of sintering, a densification rate (0.01%/min) that minimized specimen slumping via the liquid phase permitted sintering to high density. These schedules were successfully upscaled to heat treatment in a conventional furnace. The dielectric constants, quality factors, and selected temperature coefficients of 0.82‐ and 1.64‐mol%‐SnO2‐, and 1.64‐mol%‐ZrO2‐doped monophase Ba2Ti9O20 were reported.
Synthesis of Zirconia Colloids from Aqueous Salt Solutions
Authors: Lee Kangtaek , Sathyagal Arun , Carr Peter W. , McCormick Alon V.
Published: July 2010

We monitor the synthesis of ZrO2 colloids from dissolved ZrOCl2·8H2O using quasi‐elastic light scattering and cryo‐transmission electron microscopy (cryo‐TEM). We investigate the effects of both precursor salt concentration and pH on the final size distribution. We find that the initial pH plays the most important role in the final particle size and yield. These trends and cryo‐TEM observations help elucidate the roles of nucleation, aggregation, and recrystallization.
Effect of Bottom Electrode Materials and Annealing Treatments on the Electrical Characteristics of Ba0.47Sr0.53TiO3 Film Capacitors
Authors: Tsai Ming‐Shiahn , Sun Shi‐Chung , Tseng Tseung‐Yuen
Published: July 2010

The dielectric constant and leakage current density of Ba0.47Sr0.53TiO3 (BST) thin films deposited by radio‐frequency magnetron sputtering on various bottom electrode materials (Pt, Ir, IrO2/Ir, Ru, RuO2/Ru) before and after annealing in O2 and N2 ambient were investigated. Improvement in crystallinity of BST films deposited on various bottom electrodes was observed with annealing. The refractive index, dielectric constant, loss tangent, and leakage current of the films were also strongly dependent on annealing conditions. A BST thin film deposited on an Ir bottom electrode at 500°C, after 700°C annealing in O2 for 20 min, had a dielectric constant of 593 ± 5%, a loss tangent of 0.019 ± 10% at 100 kHz, a leakage current of (2.1 ± 13%) 10−8 A/cm2 at an electric field of 100 kV/cm with a delay time of 30 s, and a charge storage density of 53 ± 5% fC/μm2 at an applied field of 150 kV/cm. Based on the dielectric constant, leakage current, and reliability, the optimum material for the bottom electrode with annealing was Ir. Interdiffusion of Ru and Ti at the interface between the BST film and Ru electrode was observed in 500°‐700°C annealed samples. The 10 year lifetime of time‐dependent dielectric breakdown (TDDB) studies indicated that BST on Pt, Ir, IrO2/Ir, Ru, and RuO2/Ru had long lifetime over 10 years of operation at a voltage bias of 1 V.
Microstructural Development of Calcium alpha‐SiAlON Ceramics with Elongated Grains
Authors: Wood Chris A. , Zhao Hong , Cheng Yi‐Bing
Published: July 2010

Silicon nitride (Si3N4) and SiAlONs can be self‐toughened through the growth of elongated β‐Si3N4/β‐SiAlON grains in sintering. α‐SiAlONs usually retain an equiaxed grain morphology and have a higher hardness but lower toughness than β‐SiAlONs. The present work has demonstrated that elongated alpha‐SiAlON grains can also be developed through pressureless sintering. alpha‐SiAlONs with high‐aspect‐ratio grains in the calcium SiAlON system have exhibited significant grain debonding and pull‐out effects during fracture, which offers promise for in‐situ‐toughened α‐SiAlON ceramics.
Detection of Boron Segregation to Grain Boundaries in Silicon Carbide by Spatially Resolved Electron Energy‐Loss Spectroscopy
Authors: Gu Hui , Shinoda Yutaka , Wakai Fumihiro
Published: July 2010

Boron segregation to grain boundaries in SiC was directly observed for the first time by using spatially resolved electron energy‐loss spectroscopy methods. The hot‐pressed, fully dense material was doped with 0.3 wt% of boron and was free of other additives, except for 2 wt% of free carbon. The detection of boron was achieved in the difference spectra at all the grain boundaries that were examined. Its interfacial excess was in the range of 15–29 atoms/nm2, or approximately one monolayer. Concurrently, silicon depletion occurred at these boundaries, although to a lesser extent (−13.5 atoms/nm2 on average), which indicated that boron mainly replaces silicon and bonds with carbon at the grain boundary. These findings validate the dual role of boron at the grain boundary for promoting densification via improved grain‐boundary diffusivity while maintaining a covalent grain boundary without an oxide phase.
Effect of Nd3+ on the Spectroscopic Properties of Bismuth Borate Glasses
Authors: Chen Yujin , Huang Yidong , Huang Miaoliang , Chen Ruiping , Luo Zundu
Published: July 2010

In this paper, the spectroscopic properties of bismuth borate glasses doped with different Nd3+ concentrations have been investigated. The intensity parameters Ωt (t=2, 4, 6), spontaneous emission probability, fluorescence lifetime, radiative quantum efficiency, fluorescence branching ratio, and stimulated emission cross section were determined. The highest radiative quantum efficiency of the glasses is 54%. The optimal Nd3+ concentration in the glasses is proposed for high quantum efficiency. The good spectroscopic properties show the possible utilization of the Nd3+ doped bismuth borate glasses as laser materials.
Erosion Response of Highly Anisotropic Silicon Nitride
Authors: Zhang Yu , Cheng Yi‐Bing , Lathabai Srinivasarao , Hirao Kiyoshi
Published: July 2010

The erosion rates and impact damage of two sintered Si3N4 materials with identical compositions but different microstructures were determined using a gas‐blast‐type erosion rig. The erodent particles used were SiC grits and the impact angles investigated were 30° and 90°. It was found that the erosion behavior of the two materials could not be related to their mechanical properties, such as hardness and fracture toughness as predicted by the theoretical erosion models. In fact, a close relationship was identified between their microstructure and the erosion mechanism. Microstructures containing evenly dispersed and uniaxially oriented reinforcing whiskers promoted grain‐pullout, while the randomly oriented elongated grains hindered it.
Energy Crossovers in Nanocrystalline Zirconia
Authors: Pitcher Michael W. , Ushakov Sergey V. , Navrotsky Alexandra , Woodfield Brian F. , Li Guangshe , Boerio‐Goates Juliana , Tissue Brian M.
Published: July 2010

The synthesis of nanocrystalline powders of zirconia often produces the tetragonal phase, which for coarse‐grained powders is stable only at high temperatures and transforms into the monoclinic form on cooling. This stability reversal has been suggested to be due to differences in the surface energies of the monoclinic and tetragonal polymorphs. In the present study, we have used high‐temperature oxide melt solution calorimetry to test this hypothesis directly. We measured the excess enthalpies of nanocrystalline tetragonal, monoclinic, and amorphous zirconia. Monoclinic ZrO2 was found to have the largest surface enthalpy and amorphous zirconia the smallest. Stability crossovers with increasing surface area between monoclinic, tetragonal, and amorphous zirconia were confirmed. The surface enthalpy of amorphous zirconia was estimated to be 0.5 J/m2. The linear fit of excess enthalpies for nanocrystalline zirconia, as a function of area from nitrogen adsorption (BET) gave apparent surface enthalpies of 6.4 and 2.1 J/m2, for the monoclinic and tetragonal polymorphs, respectively. Due to aggregation, the surface areas calculated from crystallite size are larger than those measured by BET. The fit of enthalpy versus calculated total interface/surface area gave surface enthalpies of 4.2 J/m2 for the monoclinic form and 0.9 J/m2 for the tetragonal polymorph. From solution calorimetry, the enthalpy of the monoclinic to tetragonal phase transition for ZrO2 was estimated to be 10±1 kJ/mol and amorphization enthalpy to be 34±2 kJ/mol.
Quantitative Analysis of Crack Shielding Degradation During Cyclic Fatigue of Alumina
Authors: Attaoui Hassan El , Saâdaoui Malika , Chevalier Jérôme , Fantozzi Gilbert
Published: July 2010

Grain bridging degradation behind a crack tip is the main cyclic fatigue mechanism in nontransforming ceramics. In this work, a compliance function is used to quantify the shielding capacity of grain bridges during cyclic loading of alumina ceramics with different grain sizes. This allows to identify the different stages occurring during cyclic loading. Significant degradation is observed in the coarse grain material and a marked sensitivity to the loading level is outlined. At moderate loads, bridging degradation occurs prior to fatigue crack growth during an incubation period which can reach several million cycles. At low cyclic loads, the shielding capacity can be entirely degraded, leading to a cyclic fatigue threshold equivalent to that of the fine grain material.
Assisted Sintering Via Sol–Gel Deposition in Low‐Fired Ceramic Preforms
Authors: Cerecedo C. , Valcárcel V. , Guitián F.
Published: July 2010

Sol‐assisted sintering technology has already been explored for different materials. The idea consisted of increasing the resistance to fracture initiation through dispersion of nanometer‐size particles in a secondary phase. A new method for sol‐assisted sintering is proposed in this work. The main advantage is that this method does not interfere with the conformation processes, because it is applied afterwards. Low‐fired ceramic preforms are first immersed in a fluid containing a precursor of a selected gel. Then, gelation of sols is induced inside the pores, and the ceramic piece is finally sintered. The presence of deposited nanoparticles increases the available surface area, easing the sintering process. In this paper, we demonstrate that this method produces improved density and enhanced mechanical properties in cast alumina pieces. These alumina bars are low fired at 600°, 700°, 800°, and 1200°C and infiltrated with a sol containing an alumina precursor. Gelation is then induced via pH changes, and the bars are finally heated at 1600°C for 2 h. Non‐infiltrated control samples are also sintered under the same conditions for comparison. Surface area, density, and porosity measurements coherently agree with our conclusions. The effect of infiltration is also analyzed with SEM micrographs. It has also been demonstrated that the porosity of preforms to be infiltrated has a remarkable effect on the properties of the final sintered pieces, and that the standard deviation of the modulus of rupture is reduced for treated samples. This process is feasibly applicable to a range of different materials. One drawback, however, is the requirement that low‐fired preforms have sufficient chemical and mechanical stability for infiltration.
Effect of Microstructure on Sliding‐Wear Properties of Liquid‐Phase‐Sintered α‐SiC
Authors: Borrero‐López Oscar , Ortiz Angel L. , Guiberteau Fernando , Padture Nitin P.
Published: July 2010

We have studied, for the first time, the effect of the content of intergranular phase and grain size on the sliding‐wear resistance of pressureless, liquid‐phase‐sintered (LPS) α‐SiC (silicon carbide) ceramics. It was found that the sliding‐wear behavior of these ceramics is similar to what is observed in other polycrystalline ceramics: initial mild, plasticity‐controlled wear followed by severe, fracture‐controlled wear, with well‐defined wear transition. We have found that the increase in the content of intergranular phase and the grain coarsening leads to the degradation of the sliding‐wear resistance in LPS α‐SiC ceramics. A mechanistic model is used to rationalize these wear results, and to provide guidelines for the design and fabrication of low cost, highly wear‐resistant SiC‐based ceramics. This is likely to have important implications because SiC‐based materials are being used increasingly in contact‐mechanical and tribological applications.
Ink‐Jet Printing and Sintering of PZT
Authors: Wang Tianming , Derby Brian
Published: July 2010

Suspensions of Pb(Zr0.53Ti0.47)O3 (PZT)‐5H powders, with solid contents up to 40 vol% in a paraffin oil/wax medium using a mixed polyester and amine dispersant system, have been prepared for ink‐jet printing. Sufficient suspension stability for printing requires a sub‐micron particle distribution, and this could only be achieved by attrition milling the as‐received powder. The influence of printing parameters on drop velocity is shown to be consistent with simple physical models of the behavior of the suspensions. Trial objects have been fabricated with 35% PZT suspensions. These have been sintered to full density, with porosity less than 1% and without significant distortion, despite a mean linear shrinkage measured at 25%.
Calcium Phosphate‐Based Resorbable Ceramics: Influence of MgO, ZnO, and SiO2 Dopants
Authors: Bandyopadhyay Amit , Bernard Sheldon , Xue Weichang , Bose Susmita
Published: July 2010

Resorbable calcium phosphate (CaP)‐based biomaterials are important because they can significantly improve health care by shortening the time necessary for restoration of functional loading of grafted bones. Although synthetic CaPs show exceptional similarities to natural bone, however, they are deficient in one major area, in that they do not have the same mineral content of bone. The focus of our work is to understand the influence of dopants on the physical, mechanical, and biological properties of tricalcium phosphate (TCP) resorbable ceramics with special emphasis toward in vitro strength degradation and cell–materials interactions as a function of time. For this purpose, β‐TCP was doped with magnesia (MgO), zinc oxide (ZnO), and silica (SiO2). Those dopants were added as individual dopants, and their binary and ternary compositions. It was found that these dopants significantly influenced densification behavior and as sintered microstructures of TCP. In vitro mineralization studies in simulated body fluids (SBF) for 12 weeks showed apatite growth on the highly porous compositions either on the surface or inside. From scanning electron microscopic analysis it was evident that surface degradation occurred on all compositions in SBF. Compression strengths for samples up to 12 weeks in SBF showed that it is possible to tailor strength loss behavior through compositional modifications. The highest compression strength was found for binary MgO–ZnO doped TCP. Overall, samples showed either a similar strength level during the 12 weeks test period, or a continuous decrease or a continuous increase in strength depending on dopant chemistry or amount. In vitro human osteoblast cell culture was used to determine influence of dopants on cell‐materials interactions. All samples were non‐toxic and biocompatible. Dopant chemistry also influenced adhesion, proliferation, and differentiation of osteoblastic precursor cell line 1 (OPC1) cells on these matrices.
Preparation and Properties of Fine‐Grain (1−x)BiScO3−xPbTiO3 Ceramics by Two‐Step Sintering
Authors: Zou Tingting , Wang Xiaohui , Zhao Wei , Li Longtu
Published: July 2010

(1−x)BiScO3−xPbTiO3 (BSPT) nanopowder with an average grain size of 10 nm with the composition of x=0.64, which has been reported to be close to the MPB in the bulk BSPT ceramics, was successfully synthesized. Subsequently, the techniques of preparation of high‐performance fine‐grain MPB–BSPT ceramics by two‐step sintering were investigated, providing a feasible approach to produce a high‐density fine‐grain MPB–BSPT ceramic using pressureless means without any sintering aids at a low temperature of 800°C. The results have shown that the fine‐grain ceramic possesses a higher piezoelectric constant and electromechanical coupling factor than the coarse‐grain ceramic. The influences of the grain size on the piezoelectric and dielectric properties were also discussed. Within the scale of the grain sizes of our specimens, the piezoelectric constant increases up to 520 pC/N at the finest grain size of 200 nm, indicating a promising path for the improvement of the piezoelectric coefficient.
Ionic Substitutions in Biphasic Hydroxyapatite and β‐Tricalcium Phosphate Mixtures: Structural Analysis by Rietveld Refinement
Authors: Kannan S. , Goetz‐Neunhoeffer F. , Neubauer J. , Ferreira J. M. F.
Published: July 2010

The structural information on the influence of ionic additions in biphasic (hydroxyapatite (HAP) and β‐tricalciumphosphate (β‐TCP)) mixtures ranging from single ionic substitutions to combined ionic substitutions of most of the essential ions embedded in biological apatite was analyzed through the Rietveld refinement technique. The results have proved that the determined quantitative phase composition of HAP and β‐TCP in biphasic mixtures was dependent on the initial calcium (Ca) deficiency of the precursor powders precipitated from the different molar concentrations used in the synthesis. The substitution of cations (Na+, Mg2+, and K+) improved the stabilization of the β‐TCP structure whereas anions (F− and Cl−) were found incorporated at the OH− site of the HAP phase. Rietveld analysis of X‐ray powder diffraction data from the present study proved to be a powerful technique to describe the position and occupancy of certain ions like Mg2+ and Cl− in the biphasic mixtures. However, it has also shown limitations in tracking back other ions like Na+, K+, and F−, which require the use of other complementary characterization methods.
Enhanced Phase Stability and Photoluminescence of Eu3+ Modified t‐ZrO2 Nanoparticles
Authors: Mondal Aparna , Ram Shanker
Published: July 2010

Tetragonal (t) ZrO2 nanoparticles have been obtained by a partial Eu3+→Zr4+ substitution, synthesized using a simple oxalate method at a moderate temperature of 650°C in air. The Eu3+ additive, 2 mol% used according to the optimal photoluminescence (PL), gives small crystallites of the sample. On raising the temperature further, the average crystallite size D grows slowly from 16 nm to a value as big as 49 nm at 1200°C. The Eu3+:t‐ZrO2 nanoparticles have a wide PL spectrum at room temperature in the visible to near‐IR regions (550–730 nm) in the 5D0→7FJ (Eu3+), J=1–4, electronic transitions. The intensity of the 5D0→7F4 group is as large as that of the characteristic 5D0→7F2 group of the spectrum in the forced electric‐dipole allowed transitions. The enhanced t‐ZrO2 phase stability and wide PL can be attributed to the combined effects of an amorphous Eu3+‐rich surface and part of the Eu3+ doping of ZrO2 of small crystallites.
Correlation Between the Microstructure and the Electrical Properties of ZrTiO4 Ceramics
Authors: Ličina Vesna , Gajović Andreja , Moguš‐Milanković Andrea , Djerdj Igor , Tomašić Nenad , Su Dangsheng
Published: July 2010

A series of ZrTiO4 (ZT) ceramics were prepared by sintering ball‐milled precursor powders. Ceramics with homogenously dispersed micropores containing both low‐temperature (ordered) and high‐temperature (disordered) ZrTiO4 phases were achieved by sintering at 1400°C. The porosity and the morphology were modified by changing the sintering time. The impedance spectra followed the observed changes in the ceramics' microstructure. The grain boundaries' shape, rather than the grain size, has the major influence on the conductivity. The lowest value for electrical conductivity, 8.1 × 10−10 (Ω·m)−1, was obtained in the ceramics sintered at 1400°C for 4 h. This confirms the blocking effect of the imperfect grain boundaries; i.e., the defects of the grain boundaries, which were formed during the grain growth, were followed by an almost complete loss of pores.
Influence of Chemical Composition and Y2O3 on Sinterability, Dielectric Constant, and CTE of β‐SiAlON
Authors: Ganesh Ibram , Thiyagarajan Natarajan , Jana Dulal Chandra , Mahajan Yashwant Ramachandra , Sundararajan Govindan
Published: July 2010

Different types of dense β‐Si6−zAlzOzN8−z (z=1, 1.5, 2, 2.5, 3, 3.5, and 4) ceramics have been prepared following a conventional reaction sintering process at 1675°–1700°C using α‐Si3N4, α‐Al2O3, AlN, and 3–7‐wt% Y2O3 as raw materials. Sintered materials were thoroughly characterized for bulk density (BD), apparent porosity (AP), water absorption (WA) capacity, phase formation, microstructure, coefficient of thermal expansion (CTE), hardness, fracture toughness, three‐point bent strength, and dielectric constant at 16–18 GHz frequency. Characterization results suggest that an increase in z value, Y2O3 concentration, and sintering temperature leads to an increase in β‐SiAlON phase formation, BD, grain size, fracture toughness, and dielectric constant, and as a consequence, AP, WA capacity, hardness, and three‐point bend strength of the materials decrease. These materials also exhibited stable and low dielectric constants (5.67–7.67) between 16 and 18 GHz frequency. The β‐Si4Al2O2N6 exhibited a BD of ∼3.06 g/mL, AP of ∼0.01%, WA capacity of ∼0.01%, ∼94.43%β‐SiAlON phase, a hardness of ∼1317 kg/mm2, a fracture toughness of ∼3.30 MPa·m1/2, a three‐point bend strength of ∼226 MPa, a CTE of 3.628 × 10−6°C−1 between 30° and 700°C, and a dielectric constant of ∼7.206 at 17 GHz after sintering at 1675°C for 4 h with 7‐wt% Y2O3.