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Zapiola ML, Campbell CK, Butler MD, Mallory-Smith CA. Escape and establishment of transgenic glyphosate-resistant creeping bentgrassAgrostis stoloniferain Oregon, USA: a 4-year study. J Appl Ecol 2008. [DOI: 10.1111/j.1365-2664.2007.01430.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Issakainen J, Jalava J, Hyvönen J, Sahlberg N, Pirnes T, Campbell CK. Relationships of Scopulariopsis based on LSU rDNA sequences. Med Mycol 2003. [DOI: 10.1080/714043896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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3
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Abstract
Relationships between Scopulariopsis species and allied fungi were studied by sequencing a 350 bp gene region of the large subunit ribosomal RNA gene (LSU rDNA). In addition, a limited morphological dataset of nine characters was included in the cladistic analysis. Nineteen mitosporic strains (nine Scopulariopsis, five Wardomyces, three Doratomyces, one Trichurus and one Scedosporium species) and 21 meiosporic strains (14 Microascus, 4 Kernia and 3 Pithoascus species) were studied. The data were analysed using parsimony methods. Based on the analyses, the studied microascaceous fungi are divided to 12 molecular lineages. Most of the opportunistic human pathogenic Scopulariopsis species are placed in one clade ('Microascus manginii Clade'). Most synnematous anamorphs with Scopulariopsis-like conidia (Doratomyces and Trichurus) are placed in another clade ('Microascus albonigrescens Clade'), together with Wardomyces. Microascus sensu lato can be divided into seven clades which also incorporate all studied Pithoascus, Scopulariopsis, Wardomyces and Trichurus species and most of the Doratomyces species. Most of the Kernia teleomorphs and one Doratomyces species are placed in a different main clade, together with Pseudallescheria and Petriella. Future alternatives in the taxonomy of Microascus include splitting the genus or redefining it to include deviating taxa. More molecular data need to be obtained and considered in either case.
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Affiliation(s)
- J Issakainen
- Mycology and Parasitology Laboratory, Turku University Central Hospital, Turku, Finland.
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4
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Campbell CK, Edmonson PJ. Modeling a longitudinally coupled dual-mode leaky-SAW resonator filter with enhanced upper-sideband suppression. IEEE Trans Ultrason Ferroelectr Freq Control 2001; 48:1298-1301. [PMID: 11570754 DOI: 10.1109/58.949738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Recently, it has been experimentally reported that enhanced upper-sideband suppression of a longitudinally coupled (first/third) dual-mode leaky SAW (LSAW) resonator filter may be obtained by incorporation of a selectively valued capacitor between input and output terminals. In this paper, coupling-of-modes (COM) and bandstop-filter modeling is applied to realize this enhanced suppression. Tradeoffs are examined between upper and lower side-band suppression levels caused by the ensuing capacitive coupling between input and output terminals. Good agreement is obtained between this theory and reported experimental results for an 800-MHz band cellular filter.
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Affiliation(s)
- C K Campbell
- Department of Electrical and Computer Engineering, McMaster University, Hamilton, ON, Canada.
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Abstract
This study provides concise temporal and spatial characteristics of branchial chondrogenesis in embryonic sea lamprey, Petromyzon marinus, using high resolution light microscopy, transmission electron, and immunoelectron microscopy. Prechondrogenic condensations representing the first branchial arch appeared first in the mid-region of the third pharyngeal arch at 13 days post-fertilization (pf). Cartilage differentiation, defined by the presence of the unique, fibrillar, non-collagenous matrix protein characteristic of branchial cartilage, was first observed at 14 days pf. Development of lamprey branchial cartilage appeared unusual compared to that in jawed fishes, in that precartilage condensations appear as a one-cell wide orderly stack of flattened cells that extend by the addition of one dorsal and one ventral condensation. Development of lamprey gill arches from three condensations that fuse to form a single skeletal element differs from the developing gill arches of jawed fishes, where more than one skeletal element forms from a single condensation. The initial orderly arrangement of cells in the lamprey branchial prechondrogenic condensations remains throughout development. Once chondrification of the condensations begins, the branchial arches start to grow. Initially, growth occurs as a result of matrix secretion and cell migration. Later in development, the arches grow mainly by cell proliferation and enlargement. This study defines the morphology and timing of lamprey branchial chondrogenesis. Studies of lamprey chondrogenesis provide not only insight into the developmental biology of a unique non-collagenous cartilage in a primitive vertebrate but also into the general evolution of the skeletal system in vertebrates.
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Affiliation(s)
- S L Morrison
- Department of Anatomy and Physiology, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PEI, C1A 4P3 Canada
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Campbell CK, Edmonson PJ. Conductance measurements on a leaky SAW harmonic one-port resonator. IEEE Trans Ultrason Ferroelectr Freq Control 2000; 47:111-116. [PMID: 18238522 DOI: 10.1109/58.818753] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Conductance measurements are reported on a leaky SAW (LSAW) harmonic one-port resonator on a 64 degrees Y-X LiNbO(3) substrate. This employed a short three-finger IDT for fundamental and second harmonic operation together with long reflection gratings. Conductances were measured with and without the end gratings. From an analysis of the measurements, it was deduced that, for optimum second harmonic performance, the grating stop-band frequency should be higher than the IDT unperturbed center frequency. This result is in contrast to fundamental frequency resonator designs in which the end grating stop-band frequency is placed below the IDT center frequency for optimum performance.
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Affiliation(s)
- C K Campbell
- Department of Electrical & Computer Engineering, McMaster University, Hamilton, Ontario, Canada L8S 4L7.
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Abstract
Scedosporium apiospermum infection occurred in the left forearm of a patient who was taking oral prednisolone for pulmonary fibrosis. The infection appeared to follow a scratch from a blackcurrant bush. This is the first reported case in the United Kingdom of a cutaneous infection from Scedosporium apiospermum in an immunocompromised patient.
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Affiliation(s)
- C P Bower
- Department of Dermatology, Bristol Royal Infirmary, UK.
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Campbell CK, Davey KG, Holmes AD, Szekely A, Warnock DW. Comparison of the API Candida system with the AUXACOLOR system for identification of common yeast pathogens. J Clin Microbiol 1999; 37:821-3. [PMID: 9986865 PMCID: PMC84570 DOI: 10.1128/jcm.37.3.821-823.1999] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Two commercial systems for the identification of yeasts were evaluated by using 159 clinical isolates that had also been identified by conventional biochemical and morphological methods. The API Candida system correctly identified 146 isolates (91.8%), and the AUXACOLOR system correctly identified 145 isolates (91.2%). However, of the 146 isolates identified by the API Candida system, 23 required supplemental biochemical tests or morphological assessment to obtain the correct identification. The AUXACOLOR system gave no identification in 13 cases (8.2%), while the API Candida system gave an unreadable profile in only one case. Incorrect identifications were more common with the API Candida system (12 isolates; 7.5%) than with the AUXACOLOR system (1 isolate; 0.6%).
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Affiliation(s)
- C K Campbell
- Mycology Reference Laboratory, Public Health Laboratory Service, Bristol, United Kingdom
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Campbell CK, Holmes AD, Davey KG, Szekely A, Warnock DW. Comparison of a new chromogenic agar with the germ tube method for presumptive identification of Candida albicans. Eur J Clin Microbiol Infect Dis 1998; 17:367-8. [PMID: 9721972 DOI: 10.1007/bf01709466] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- C K Campbell
- Mycology Reference Laboratory, Public Health Laboratory Service, Bristol, UK
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Holzel H, Macqueen S, MacDonald A, Alexander S, Campbell CK, Johnson EM, Warnock DW. Rhizopus microsporus in wooden tongue depressors: a major threat or minor inconvenience? J Hosp Infect 1998; 38:113-8. [PMID: 9522289 DOI: 10.1016/s0195-6701(98)90064-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The investigation and management of an apparent outbreak of Rhizopus spp. in a London paediatric referral centre between September 1995 and April 1996 is described. The organism was identified in microbiological surveillance samples from 23 patients nursed in four hospital areas. Investigations revealed the presence of the organism in spatulae from all ward areas investigated and from closed boxed containers held in the central hospital stores obtained from a new supplier. In contrast, culture of spatulae from the initial supplier failed to yield any fungal isolates. The incident was reported to the Medical Device Agency (MDA), the Central Public Health Laboratory Service (CPHLS) and the Birmingham PHLS. A statement was prepared for the weekly Communicable Disease Report and a hazard warning issued by the MDA. The spatulae were withdrawn from use and the contract with the original supplier was re-established. This incident resulted in contamination of samples only and no patient involvement. It highlights the problems which may follow use of equipment for unintended purposes and the need for good manufacturing practice guidelines to be applied to non-sterile equipment used in direct patient care.
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Affiliation(s)
- H Holzel
- Great Ormond Street Hospital for Children NHS Trust, London, UK
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Abstract
Onychocola canadensis is a recently recognized cause of human nail infection. We present the first four cases of onychomycosis caused by this organism among patients resident in the UK.
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Affiliation(s)
- C K Campbell
- Mycology Reference Laboratory, Public Health Laboratory Service, Bristol, UK
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Issakainen J, Jalava J, Eerola E, Campbell CK. Relatedness of Pseudallescheria, Scedosporium and Graphium pro parte based on SSU rDNA sequences. J Med Vet Mycol 1997; 35:389-98. [PMID: 9467105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Genetic relatedness of 10 strains of opportunistic human pathogenic fungi in the genera Pseudallescheria and Scedosporium and related fungi including Petriella setifera, Graphium tectonae and Ceratocystis fimbriata, were tested by sequencing the entire SSU rDNA. From these molecular data, the imperfect genus Scedosporium can be divided in two, S. prolificans being separable from the S. apiospermum complex. Nearest sexual relatives of S. prolificans seem to be in the microascalean genus Petriella. Strains of Ps. boydii and S. apiospermum, although differing by their previously known DNA/DNA reassociation values, were not separable from each other once a 380 nucleotide long insertion had been removed from the sequence of the two S. apiospermum strains tested. The SSU rDNA of Ps. ellipsoidea is identical to that of Ps. boydii. Fungi which have been known to have Graphium anamorphs can be divided in at least three groups, one of which is related to Petriella and includes Graphium tectonae.
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Affiliation(s)
- J Issakainen
- Turku University Central Hospital, Mycology Laboratory, Finland.
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Abstract
We describe the first case of allergic fungal sinusitis (AFS) associated with Schizophyllum commune. Histological diagnosis was made on the mucinous material from the sinus which contained eosinophils, fungal hyphae and Charcot-Leyden crystals. The fungal isolate was identified as S. commune on the basis of its colonial morphology and minute peg-like outgrowths from vegetative hyphae and clamp connections. The optimal treatment of AFS is not known but may involve surgical debridement followed by systemic corticosteroids, gradually reduced, with the patient being maintained on inhaled corticosteroids. Oral itraconazole could be added to the regimen of those patients in whom frequent recurrences occur after debridement or when there is histological evidence of severe pressure erosion.
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Affiliation(s)
- S Clark
- Department of Microbiology, Whittington Hospital, London, UK
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Yeghen T, Fenelon L, Campbell CK, Warnock DW, Hoffbrand AV, Prentice HG, Kibbler CC. Chaetomium pneumonia in patient with acute myeloid leukaemia. J Clin Pathol 1996; 49:184-6. [PMID: 8655695 PMCID: PMC500362 DOI: 10.1136/jcp.49.2.184] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
A patient with relapsed refractory acute myeloid leukaemia developed typical fungal lung lesions despite intravenous amphotericin B prophylaxis. Chaetomium globosum was cultured from the resected right lower lobe. Histology showed branching hyphae negative for common Aspergillus species by immunohistochemical staining. Previous reports of invasive disease caused by Chaetomium and some applications of immunohistochemical staining for Aspergillus are discussed.
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Affiliation(s)
- T Yeghen
- Department of Microbiology, Royal Free Hospital, Hampstead, London
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Affiliation(s)
- K G Davey
- PHLS Mycology Reference Laboratory, Bristol
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Abstract
AIMS To compare the AUXACOLOR yeast identification system with the API 20C system. METHODS Yeast isolates (n = 215), comprising 16 species, were identified using the AUXACOLOR system and the API 20C system. Isolates that could not be identified with the API 20C system or which produced discrepant results in the two systems were identified by assimilation and fermentation procedures. RESULTS AUXACOLOR correctly identified 150 (85.7%) of 175 germ tube negative isolates while API 20C identified 155 (88.6%). Incorrect identifications were more common with API 20C (7.4%) than with AUXACOLOR (3.7%). Of 110 isolates of four common pathogens (Candida glabrata, C parapsilosis, C tropicalis, and Cryptococcus neoformans), 82.7% (91/110) were identified by AUXACOLOR while API 20C identified 74.5% (82/110). Of 65 less common germ tube negative isolates, 55.4% (36/65) were identified by AUXACOLOR while API 20C identified 63.1% (41/65). CONCLUSION Although it has a limited database of 26 species, the AUXACOLOR system is a useful method for identification of germ tube negative clinical yeast isolates. Compared with the API 20C, the AUXACOLOR system is simpler and quicker to set up, easier to interpret, and comparable in cost.
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Affiliation(s)
- K G Davey
- PHLS Mycology Reference Laboratory, Public Health Laboratory, Bristol
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18
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Abstract
There is sufficient evidence from the literature to demonstrate the risk involved in handling the dimorphic pathogens without suitable containment facilities. The number of fungi considered a severe hazard is fortunately low, but impeccable working practices and continuous vigilance are necessary to minimize accidents and to prevent them leading to worse catastrophies. The continuing discovery of new opportunistic pathogenic fungi requires frequent, objective and cautious review of the hazard groupings to accommodate them.
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Affiliation(s)
- C K Campbell
- PHLS Mycology Reference Laboratory, Public Health Laboratory, Bristol, UK
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Abstract
Seventeen cases of infections due to Cunninghamella species have been reported worldwide in humans, and there have been only three survivors. We report a case of paranasal sinusitis due to Cunninghamella bertholletiae in an elderly patient who had diabetes mellitus and myelodysplasia. After receiving 7 weeks of therapy with deoxycholate amphotericin B (44 mg/kg or a total of 3 g) and rifampin, the patient was cured and did not have to undergo radical surgery.
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Affiliation(s)
- T T Ng
- Department of Microbiology, Hope Hospital, Manchester, United Kingdom
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Soledad Cuétara M, Sanz F, del Palacio A, Campbell CK, Aguado JM, Lizasoain M, Gómez-Sánchez MA, Castejón AM. [Discovery of a mycelial fungus in a blood culture (Bactec NR-860) from a patient with an implantable reservoir]. Enferm Infecc Microbiol Clin 1993; 11:567-9. [PMID: 8142510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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21
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Sanz F, Soledad Cuétara M, del Palacio A, Campbell CK, Johnson L, Urruzunu P, Pía Roiz M. [Problems found in the isolation of mycelial fungi (Fusarium solani) from blood culture (Bacter NR-860)]. Enferm Infecc Microbiol Clin 1993; 11:490-3. [PMID: 8305557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
BACKGROUND F. solani fungemia is unusual. Patients at risk are immunosuppressed, have underlying malignancy or severe debilitating diseases. METHODS We report two cases of F. solani fungemia in two non neutropenic patients who had been treated with wide-spectrum antibiotics an/or systemic corticosteroids, parenteral nutrition and intravenous lines. Bactec NR-860 (Becton-Dickinson) system was used, and growth was detected in aerobic conditions (between 3-7 days of incubation). RESULTS Removal of the catheters with or without i.v. amphotericin B were used successfully. CONCLUSION The spectrum of Fusarium sp. fungemia is discussed. Current available antifungal therapy is also reviewed.
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Affiliation(s)
- F Sanz
- Public Health Laboratory, Micological Reference Laboratory, Londres, Reino Unido
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Abstract
The effects of 3-methylcholanthrene, butylated hydroxyanisole, and phenobarbital on the expression of glutathione S-transferase (GST, EC 2.5.1.18) were examined in the human parasite Schistosoma mansoni. GST specific activity toward 1-chloro-2,4-dinitrobenzene increased by 170% in parasites recovered from mice injected with 3-methylcholanthrene and 230% in parasites recovered from mice maintained on a diet containing butylated hydroxyanisole. These increases in specific enzyme activity were paralleled by accumulation of mRNA hybridizing to pGT16.4, a cDNA clone that encodes the most abundant GST subunit, SmGST-3. Northern hybridization analysis showed a 5-fold increase in mRNA hybridizing to pGT16.4 72 h after exposure to 3-methylcholanthrene, a 10-fold increase after 12 days exposure to butylated hydroxyanisole, and a 6-fold increase 16 h after treatment with phenobarbital. In contrast, no accumulation of mRNA hybridizing to either of two other cDNA clones that encode the SmGST-4 and SmGST-6 subunits was detected. Hybrid select translation using pGT16.4 combined with reverse-phase high-pressure liquid chromatographic analysis demonstrated that in addition to SmGST-3 mRNA, the clone also hybridized to mRNA species encoding the SmGST-1 subunit, a member of the same isoenzyme family. High-pressure liquid chromatographic analysis of GST affinity purified from butylated hydroxyanisole-exposed parasites revealed a 2.5-fold increase in the concentration of SmGST-1 and SmGST-3 present compared with an equivalent amount of tissue from control organisms. There was no change, however, in the SmGST-1 to SmGST-3 ratio (1:6), indicating that both subunits were induced to the same extent by this agent. The results of these studies suggest that alterations in GST expression may influence the parasite's survival within the host environment.
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Affiliation(s)
- E A Vande Waa
- Department of Comparative Biosciences, University of Wisconsin-Madison 53706
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23
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Edmonson PJ, Smith PM, Campbell CK. Injection locking techniques for a 1-GHz digital receiver using acoustic-wave devices. IEEE Trans Ultrason Ferroelectr Freq Control 1992; 39:631-637. [PMID: 18267674 DOI: 10.1109/58.156181] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The use of surface-transverse-wave (STW) resonator-based oscillators as amplifiers and as carrier recovery elements is discussed. It is demonstrated that these oscillators can amplify phase-shift-keyed signals with very little added noise, while providing a constant output power. Their performance in carrier recovery amplifications is analyzed. Experimental results showing the amplification with more than 80 dB of dynamic range of a 2 Mb/s BPSK signal and the carrier recovery of an 8 Mb/s signal with a 1-GHz STW oscillator are shown.
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Affiliation(s)
- P J Edmonson
- Dept. of Electrotechnol., Mohawk Coll., Hamilton, Ont
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Campbell CK, Edmonson PJ, Smith PM. Transverse modes in one-port SAW resonators. IEEE Trans Ultrason Ferroelectr Freq Control 1992; 39:785-787. [PMID: 18267696 DOI: 10.1109/58.165565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The S(11) and equivalent S(21) frequency responses of a one-port surface acoustic wave (SAW) resonator with transverse modes derived from one-dimensional coupling-of-modes and transmission-matrix analysis. The two-dimensional nature of the problem is approximated by a summation of one-dimensional mode responses for each transverse mode. Comparison between theory and experimental data for a commercial 280-MHz one-port SAW resonator shows good agreement for the placement of transverse modes.
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Affiliation(s)
- C K Campbell
- Dept. of Electr. and Comput. Eng., McMaster Univ., Hamilton, Ont
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Campbell CK, Smith PM, Edmonson PJ. Aspects of modeling the frequency response of a two-port waveguide-coupled SAW resonator-filter. IEEE Trans Ultrason Ferroelectr Freq Control 1992; 39:768-773. [PMID: 18267693 DOI: 10.1109/58.165562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Coupling-of-modes-in-time and coupling-of-modes-in-space analyses are applied to the modeling of a two-port two-pole waveguide-coupled SAW resonator filter. Modeling is applied to a lumped equivalent circuit and a distributed circuit. While the accuracy of the coupling estimation dictates the exact mode-splitting and bandwidth, the ensuing computations can give a good representation of the amplitude and phase response, including the effect of degenerate transverse modes.
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Affiliation(s)
- C K Campbell
- Dept. of Electr. and Comput. Eng., McMaster Univ., Hamilton, Ont
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Abstract
A fungus from bronchial lavage fluid from a patient with pulmonary infiltration was isolated in pure culture and identified as a species of Pseudomicrodochium. It is compared and contrasted with other species of the genus, in particular P. suttonii, and formally described as P. fusarioides.
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Affiliation(s)
- B C Sutton
- International Mycological Institute, Kew, Surrey, UK
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27
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Campbell CK. Modelling the transverse-mode response of a two-port SAW resonator. IEEE Trans Ultrason Ferroelectr Freq Control 1991; 38:237-242. [PMID: 18267580 DOI: 10.1109/58.79608] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
An equation is derived for the transverse-mode frequencies of a two-port surface-acoustic-wave (SAW) resonator with uniform reflection gratings. It is postulated that only odd-order (symmetric) transverse modes should be excited in such a grating, due to its symmetrical placement with respect to the interdigital transducer (IDT). Frequency response modeling involves a summation of one-dimensional transmission-matrix computations for the fundamental mode and participating transverse ones. Excellent agreement is obtained between theory and experiment for a 360-MHz resonator with three close-in transverse modes, attributed to symmetric modes of odd order m=3, 5, 7.
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Affiliation(s)
- C K Campbell
- Dept. of Electr. and Comput. Eng., McMaster Univ., Hamilton, Ont
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28
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Affiliation(s)
- C K Campbell
- Mycological Reference Laboratory, PHLS Central Public Health Laboratory, London
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Saw CB, Campbell CK. Sampling effect of distributed reflector arrays within a single-phase unidirectional SAW transducer. IEEE Trans Ultrason Ferroelectr Freq Control 1990; 37:116-117. [PMID: 18285022 DOI: 10.1109/58.46976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
A noteworthy feature of the group-type single-phase unidirectional transducer is that it can permit wideband low-loss surface-acoustic-wave (SAW) comb filter operation. This is shown to be due to the sampling imposed by the distributed reflector gratings. The capability is illustrated theoretically and experimentally for a 65-MHz comb filter on 128 degrees Y-X lithium niobate, with 5 comb modes of 585-kHz bandwidth each, together with 2.6-dB minimum insertion loss and overall 50% fractional bandwidth.
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Affiliation(s)
- C B Saw
- Bell Northern Res. Ltd., Ottawa, Ont
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30
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Bailey CG, Campbell CK. Design of a phase-locked multimode SAW oscillator. IEEE Trans Ultrason Ferroelectr Freq Control 1990; 37:277-278. [PMID: 18285042 DOI: 10.1109/58.55319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
A 60-100 MHz multimode SAW (surface acoustic wave) oscillator with comb spacing Deltaf=10 MHz used a low-loss SPUDT (single-phase unidirectional transducer) comb filter in conjunction with two varactor-based control elements and two feedback loops, for mode selection and stability enhancement over long dwell times. The end aim is to reduce close-in phase noise over that of the unlocked oscillator, corresponding to improved intermediate-term time-domain stability. Frequency deviation was less than 20 Hz over two hours in each of the five comb modes.
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Affiliation(s)
- C G Bailey
- Microwave Acoust. Lab., McMaster Univ., Hamilton, Ont
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31
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Abstract
A mycology quality assessment scheme introduced in 1986 was assessed: 289 laboratories participated in the scheme, and six distributions, each containing four specimens, were made. Levels of performance varied considerably among participating laboratories: performance was highest with the commoner organisms distributed, but some laboratories, encouragingly, achieved a consistently high level of species identification. A questionnaire distributed to participants showed that a wide range of methods are commonly used, some of which are contrary to good practice. As the scheme continues, selection of organisms considered to be relevant and of use to participants will become difficult.
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Affiliation(s)
- S F Perry
- Division of Microbiological Reagents, Mycological Reference Laboratory, Colindale, London
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Smith PM, Campbell CK. A theoretical and experimental study of low-loss SAW filters with interdigitated interdigital transducers. IEEE Trans Ultrason Ferroelectr Freq Control 1989; 36:10-15. [PMID: 18284944 DOI: 10.1109/58.16963] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
A study of low-loss surface-acoustic-wave (SAW) interdigitated interdigital transducer (IIDT) structures is presented. A model based on mixed scattering matrices was used in the analysis. It is shown that the inherent comb frequency response of the IIDT can be smoothed by slanting the transducers in the structure. Alternatively, the combs can be enhanced to produce a compact low-loss feedback element for potential application in multimode oscillators. Experimental verification of the analysis is provided by a 3:2 slanted-finger IIDT filter with a 10% relative bandwidth of 5.9-dB insertion loss, and a comb filter with 13.4-dB insertion loss and comb spacing of about 3 MHz. The measured responses agree quite well with the theory.
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Affiliation(s)
- P M Smith
- Dept. of Electr. and Comput. Eng., McMaster Univ., Hamilton, Ont
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Peto TE, Bull R, Millard PR, Mackenzie DW, Campbell CK, Haines ME, Mitchell RG. Systemic mycosis due to Penicillium marneffei in a patient with antibody to human immunodeficiency virus. J Infect 1988; 16:285-90. [PMID: 3294300 DOI: 10.1016/s0163-4453(88)97700-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Systemic mycosis due to Penicillium marneffei is described in a man infected with human immunodeficiency virus and who had travelled in S.W. China. He responded completely to treatment with amphotericin B and a prolonged course of ketoconazole. Problems of diagnosis are discussed and all previously reported cases reviewed.
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Affiliation(s)
- T E Peto
- Nuffield Department of Clinical Medicine, John Radcliffe Hospital, Oxford, U.K
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Saw CB, Smith PM, Edmonson PJ, Campbell CK. Mode selection in a multimode SAW oscillator using FM chirp mixing signal injection. IEEE Trans Ultrason Ferroelectr Freq Control 1988; 35:390-395. [PMID: 18290165 DOI: 10.1109/58.20460] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Mode-selection control of a multimode surface-acoustic-wave (SAW) oscillator has been obtained using SAW linear FM chirp signal injection. The prototype 60-100-MHz SAW oscillator design employed a single-phase unidirectional transducer (SPUDT) low-loss comb filter in the feedback loop, with minimum insertion loss of approximately 3.7 dB. Mode selection was achieved using an injection signal derived from the mixed output of two 27.5-52.5-MHz up- and down-chirp SAW filters. Mode switching times of less, similar2 mus were obtained. The device could be useful as a local oscillator on frequency-agile radars, where hopping is required over a moderate number of frequencies.
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Affiliation(s)
- C B Saw
- Dept. of Electr. and Comput. Eng., McMaster Univ., Hamilton, Ont
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Abstract
A hyphomycete isolated from a pale-grain eumycetoma in an indian male patient is described as a species of a new form-genus, Polycytella hominis. The fungus is characterized by elongate multiseptate conidia in which only the apical compartment becomes thick-walled and retains viable cytoplasm. The appearance of P. hominis in the host tissues is described and compared with other pale-grain eumycetomas.
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Campbell CK, Saw CB. Analysis and Design of Low-Loss SAW Filters Using Single-Phase Unidirectional Transducers. IEEE Trans Ultrason Ferroelectr Freq Control 1987; 34:357-367. [PMID: 18291858 DOI: 10.1109/t-uffc.1987.26954] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
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Smith P, Campbell CK. The Design of SAW Linear Phase Filters Using the Remez Exchange Algorithm. IEEE Trans Ultrason Ferroelectr Freq Control 1986; 33:318-323. [PMID: 18291790 DOI: 10.1109/t-uffc.1986.26835] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
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Abstract
Despite an apparent stabilizing of nomenclature and concepts involved in fungal conidiogenesis during the past decade, there is now evidence that a much more complex and demanding approach to the descriptive study of processes involved in conidial formation would allow a more phylogenetically realistic classification of anamorphic fungi. The present review attempts to evaluate data on the human pathogenic molds in light of this new approach and to relate conidiogenesis to the known teleomorph connections of the fungi concerned. It is hoped that by treating the species in groups corresponding to their sexual affinities, it may be possible to infer homologous forms of conidiogenesis by comparative morphology and development.
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Abstract
A 14-year-old child from Iraq presented with an acute febrile illness accompanied by large necrotic skin lesions and bronchopneumonia from which he subsequently died. The infection was caused by an unusual zygomycete fungus Saksenaea vasiformis. Previous reports of infection with this organism are rare and tissue invasion has usually followed traumatic injury. In the child reported here no predisposing abnormalities were apparent.
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Hay RJ, Campbell CK, Wingfield R, Clayton YM. A comparative study of dermatophytosis in coal miners and dermatological outpatients. Br J Ind Med 1983; 40:353-5. [PMID: 6871126 PMCID: PMC1069334 DOI: 10.1136/oem.40.3.353] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The causative organisms and susceptibility factors were compared in two groups of individuals with tinea pedis, coal miners (234) and dermatological outpatients (244). Trichophyton rubrum was the commonest dermatophyte in both groups, being isolated from 71% of infected miners and 77% of infected outpatients. The incidence of atopy in the outpatients, but not the miners, was significantly higher in individuals with T rubrum infections than in control groups. An analysis of the data from both groups suggests that in the coal miners, in whom there is a high risk of endemic dermatophytosis, susceptibility factors such as atopy are of less importance than in patients seen in a dermatological outpatient clinic in whom the risk of exposure to other sources of dermatophytosis is low.
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Abstract
Slide cultures of the type strain of P. boydii Shear, showed percurrent production of conidia by light microscopy over a period of several hours. Scanning and transmission electron microscopy were used to examine the conidiogenesis. The conidiogenous cells developed annular ridges rather than typical annellophoric scars. Evidence that these ridges represented sequential spore production was shown by T.E.M. in the form of a discontinuity of the outer conidiophore wall at the widest point of each ridge.
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Campbell CK. Studies on Hendersonula toruloidea isolated from human skin and nail. Sabouraudia 1974; 12:150-6. [PMID: 4854499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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