bluuebunny/crossref_metadata_2025 huggingface dataset:
Susceptibility Pattern and Molecular Type of Species-Specific
Candida
in Oropharyngeal Lesions of Indian Human Immunodeficiency Virus-Positive Patients
Authors: Abdul Lattif Ali , Banerjee Uma , Prasad Rajendra , Biswas Ashutosh , Wig Naveet , Sharma Neeraj , Haque Absarul , Gupta Nivedita , Baquer Najma Z. , Mukhopadhyay Gauranga
Published: March 2004

A study of oropharyngeal candidiasis (OPC) in Indian human immunodeficiency virus (HIV)/AIDS patients was conducted over a period of 15 months. This study revealed that 75% of the HIV/AIDS patients had OPC. MIC testing revealed that 5% of the
Candida
isolates were fluconazole resistant. A correlation between CD4
+
-T-cell counts and development of OPC in HIV/AIDS patients was also observed. Molecular typing of
C. albicans
isolates showed that all were genetically unrelated.
Evaluation of Different Methods To Detect Methicillin Resistance in Small-Colony Variants of
Staphylococcus aureus
Authors: Kipp Frank , Becker Karsten , Peters Georg , von Eiff Christof
Published: March 2004

To evaluate different methods for their abilities to detect methicillin resistance in small-colony variants (SCVs) of
Staphylococcus aureus
, 11 different methicillin-resistant
S. aureus
(MRSA) clones with the SCV phenotype were used in this study. The slow growth of SCVs often makes testing by disk diffusion or by automated methods invalid. Only detection of the
mecA
gene by PCR and the MRSA-Screen latex agglutination test using a higher colony number were shown to be reliable methods to rapidly detect methicillin resistance in these variants.
Assessment of Evolution of Pandemic
Vibrio parahaemolyticus
by Multilocus Sequence Typing
Authors: Chowdhury Nandini Roy , Stine O. Colin , Morris J. Glenn , Nair G. B.
Published: March 2004

The genetic relatedness of 81 isolates of
Vibrio parahaemolyticus
was assessed by multilocus sequence typing. The strain with serotype O3:K6 emerged as a pandemic pathogen in 1996, with subsequent expansion to include strains having serotypes O1:KUT, O4:K68, and O1:K25. Sequence data from
gyrB
,
recA
,
dnaE
, and
gnd
revealed that 16 distinct serogroups isolated prior to the pandemic were highly variable and only isolates of serogroup O3:K6 shared two alleles with the pandemic strains. The pandemic strains regardless of serotype were clonal, with 51 of 54 isolates having the identical allelic profile (AP). Serotype alone did not adequately define a pandemic strain: among O1:KUT strains tested, seven strains with the identical pandemic AP carried previously described pandemic markers, while five nonpandemic strains had five distinct APs. Our sequence data provide strong molecular support for the clonal origin of pandemic
V. parahaemolyticus
O3:K6 and suggest that strains within such a clonal group may acquire previously identified serotypes.
Evaluation of Penicillin Binding Protein 2a Latex Agglutination Assay for Identification of Methicillin-Resistant
Staphylococcus aureus
Directly from Blood Cultures
Authors: Chapin Kimberle C. , Musgnug Michael C.
Published: March 2004

The penicillin binding protein 2a (PBP2a) latex agglutination test using a blood culture pellet was compared to the oxacillin screen agar method using isolated colonies. For blood cultures positive for
Staphylococcus aureus
(
n
= 70), the direct PBP2a test was 18% sensitive and 100% specific. The PBP2a test shows poor sensitivity when used directly with positive blood cultures.
Stability of Mueller-Hinton Agar Supplemented with Glucose and Methylene Blue for Disk Diffusion Testing of Fluconazole and Voriconazole
Authors: Pfaller M. A. , Boyken L. , Messer S. A. , Hollis R. J. , Diekema D. J.
Published: March 2004

The shelf life of Mueller-Hinton agar supplemented with 2% glucose and methylene blue (0.5 μg/ml) (MH-GMB) prepared in the laboratory to test disk diffusion of voriconazole and fluconazole was assessed using quality control (QC) strains of
Candida albicans
ATCC 90028,
Candida krusei
ATCC 6258, and
Candida parapsilosis
ATCC 22019. MH-GMB agar plates were prepared as described in National Committee for Clinical Laboratory Standards document M44-P, and isolates were tested using 25-μg fluconazole disks and 1-μg voriconazole disks over a 36-day period. Zone diameters for fluconazole and voriconazole varied by no more than 4 mm over the study period, and 95 to 100% of results were within the established QC limits for the strains tested. Prepared MH-GMB agar plates provide acceptable performance for disk diffusion testing for at least 30 days when stored at 5°C.
Identification of a
Mycobacterium tuberculosis
Strain with Stable, Low-Level Resistance to Isoniazid
Authors: Madison Bereneice M. , Siddiqi Salman H. , Heifets Leonid , Gross Wendy , Higgins Mike , Warren Nancy , Thompson Anthony , Morlock Glenn , Ridderhof John C.
Published: March 2004

We have identified a potential quality control strain of
Mycobacterium tuberculosis
to monitor isoniazid susceptibility testing. This strain (strain A) has a stable phenotypic low-level resistance to isoniazid, has a mutation of C (−15) → T in the
inhA
promoter region, and gave consistent susceptibility test results in 141 laboratories.
Cytomegalovirus Quantitation by Real-Time PCR Is Unaffected by Delayed Separation of Plasma from Whole Blood
Authors: Nesbitt Shannon E. , Cook Linda , Jerome Keith R.
Published: March 2004

A previous study suggested that delayed sample preparation can cause a false-positive plasma cytomegalovirus (CMV) PCR. We evaluated 78 samples submitted for CMV testing, and we report that a 24-h delay in plasma separation did not affect viral quantitation by real-time PCR. Laboratories should evaluate specimen handling requirements for their own PCR technology.
Hepatitis C Virus Isolates from Argentina Disclose a Novel Genotype 1-Associated Restriction Pattern
Authors: Gismondi María Inés , Staendner Lothar Heinrich , Grinstein Saúl , Guzmán Carlos Alberto , Preciado María Victoria
Published: March 2004

Hepatitis C virus isolates which disclosed a novel genotype 1-associated restriction pattern by restriction fragment length polymorphism analysis were characterized. Except for a mother and child pair, the patients were unrelated. Sequence analysis showed a G→A substitution leading to a new
Rsa
I recognition site. Phylogenetic analysis revealed that these isolates constitute a novel genetic lineage within the main cluster of genotype 1 strains.
Genetic Diversity of Norovirus and Sapovirus in Hospitalized Infants with Sporadic Cases of Acute Gastroenteritis in Chiang Mai, Thailand
Authors: Hansman Grant S. , Katayama Kazuhiko , Maneekarn Niwat , Peerakome Supatra , Khamrin Pattara , Tonusin Supin , Okitsu Shoko , Nishio Osamu , Takeda Naokazu , Ushijima Hiroshi
Published: March 2004

Stool specimens from hospitalized infants with sporadic gastroenteritis in Chiang Mai, Thailand, between July 2000 and July 2001 were examined for norovirus and sapovirus by reverse transcription-PCR and sequence analysis. These viruses were identified in 13 of 105 (12%) specimens. One strain was found to be a recombinant norovirus.
DifferentialIdentification of
Mycobacterium tuberculosis
Complexand Nontuberculous Mycobacteria by Duplex PCR Assay Using the RNAPolymerase Gene(
rpoB
)
Authors: Kim Bum-Joon , Hong Seong-Karp , Lee Keun-Hwa , Yun Yeo-Jun , Kim Eui-Chong , Park Young-Gil , Bai Gil-Han , Kook Yoon-Hoh
Published: March 2004

A
novel duplex PCR method that can amplify the 235- and 136-bp
rpoB
DNAs of
Mycobacterium tuberculosis
complex and nontuberculous mycobacteria (NTM), respectively, with two
different sets of primers was used to differentially identify 44
reference strains and 379 clinical isolates of mycobacteria in a
single-step assay. Showing 100% sensitivity and specificity, the
duplex PCR method could clearly differentiate
M
.
tuberculosis
complex and NTM strains. In addition, restriction
fragment length polymorphism analysis and direct sequencing of the
amplicon of NTM could be used to supplement species
identification.
Correlation between Detection Rates of Periodontopathic Bacterial DNA in Carotid Coronary Stenotic Artery Plaque and in Dental Plaque Samples
Authors: Ishihara Kazuyuki , Nabuchi Akihiro , Ito Rieko , Miyachi Kouji , Kuramitsu Howard K. , Okuda Katsuji
Published: March 2004

Utilizing PCR, the 16S rRNA detection rates for
Porphyromonas gingivalis
,
Actinobacillus actinomycetemcomitans
,
Bacteroides forsythus
,
Treponema denticola
, and
Campylobacter rectus
in samples of stenotic coronary artery plaques were determined to be 21.6, 23.3, 5.9, 23.5, and 15.7%, respectively. The detection rates for
P. gingivalis
and
C. rectus
correlated with their presence in subgingival plaque.
First Molecular Identification of Human Dobrava Virus Infection in Central Europe
Authors: Klempa Boris , Schütt Morten , Auste Brita , Labuda Milan , Ulrich Rainer , Meisel Helga , Krüger Detlev H.
Published: March 2004

Viral RNA was amplified by reverse transcription-PCR from a patient suffering from hemorrhagic fever with renal syndrome (HFRS) in Germany. The virus strain could be assigned to the Dobrava hantavirus (DOBV). This is the first molecular identification of human infection by DOBV in central Europe and the first proof that a virus strain related to the DOBV-Aa lineage, carried by
Apodemus agrarius
rodents, is able to cause HFRS.
Multiplex PCR Assay for Direct Identification of Group B Streptococcal Alpha-Protein-Like Protein Genes
Authors: Creti Roberta , Fabretti Francesca , Orefici Graziella , von Hunolstein Christina
Published: March 2004

We
developed a group B streptococcus multiplex PCR assay which allows, by
direct analysis of the amplicon size, determination of the surface
protein antigen genes of alpha-C protein, epsilon protein, Rib, Alp2,
Alp3, and Alp4. The multiplex PCR assay offers a rapid and
simple method of subtyping
Streptococcus agalactiae
based on
surface protein
genes.
Rapid Detection of
Klebsiella pneumoniae
from Blood Culture Bottles by Real-Time PCR
Authors: Kurupati Prathiba , Chow Carol , Kumarasinghe Gamini , Poh Chit Laa
Published: March 2004

A LightCycler real-time PCR hybridization probe-based assay which detects a partial
Klebsiella pneumoniae
16S rRNA gene was developed for the rapid identification of
K. pneumoniae
directly from growth-positive blood culture bottles (BACTEC 9240 system) within 2 h. No cross-reactivity was observed with 65 negative-control blood cultures that grew bacteria other than
K. pneumoniae
and 48 negative blood cultures from double-blind experiments, thus demonstrating 100% specificity when compared to results of conventional biochemical characterization. The assay also showed 100% sensitivity, as it correctly identified all 142 positive-control blood cultures and 4 from double-blind trials.
Highly Conserved Alpha-Toxin Sequences of Avian Isolates ofClostridium perfringens
Authors: Sheedy Scott A. , Ingham Aaron B. , Rood Julian I. , Moore Robert J.
Published: March 2004

Clostridium perfringenscauses necrotic enteritis in chickens, and alpha-toxin has been suggested to be a key virulence determinant. Analysis of the alpha-toxin of 25 chicken-derivedC. perfringensstrains demonstrated high homology to mammal-derived strains rather than to the only avian-derivedC. perfringensalpha-toxin sequence reported previously.
Development of a Diagnostic PCR Assay Targeting the Mn-Dependent Superoxide Dismutase Gene (sodA) for Identification ofStreptococcus gallolyticus
Authors: Sasaki Eiki , Osawa Ro , Nishitani Yosuke , Whiley Robert A.
Published: March 2004

A PCR-based assay to identifyStreptococcus gallolyticushas been developed. The assay uses an oligonucleotide primer pair targeting a partial sequence of the manganese-dependent superoxide dismutase gene (sodA). The assay distinguished members of theS. gallolyticusgroup from other, closely related taxa successfully by yielding a 408-bp specific amplicon.
Occurrence of
Campylobacter jejuni
in Pets Living with Human Patients Infected with
C. jejuni
Authors: Damborg Peter , Olsen Katharina E. P. , Møller Nielsen Eva , Guardabassi Luca
Published: March 2004

Campylobacter jejuni
was recovered from four dogs (11%) and four cats (33%) living with Danish human patients infected with
C. jejuni
. Pulsed-field gel electrophoresis (PFGE) analysis revealed the occurrence of the same quinolone-resistant strain in a girl and her dog.
C. jejuni
isolates with closely related (>95% similarity) PFGE profiles occurred in humans and pets from different Danish counties.
Disseminated Basidiobolomycosis in an Immunocompetent Woman
Authors: Bigliazzi Caterina , Poletti Venerino , Dell'Amore Davide , Saragoni Luca , Colby Thomas V.
Published: March 2004

Basidiobolomycosis is a chronic subcutaneous infection of the trunk and limbs due toBasidiobolus ranarum.The disease is well known in tropical areas, although recent cases of gastrointestinal basidiobolomycosis have also been reported in Arizona. We describe a young immunocompetent women who had presented with eosinophilia and lung infiltrates. She subsequently died, and diagnosis of disseminated basidiobolomycosis was made on the basis of histological features at autopsy.
Two Cases of Fatal Necrotizing Fasciitis Caused by
Photobacterium damsela
in Japan
Authors: Yamane Kunikazu , Asato Jun , Kawade Naofumi , Takahashi Hajime , Kimura Bon , Arakawa Yoshichika
Published: March 2004

We encountered two cases of fatal necrotizing fasciitis caused by
Photobacterium damsela
in Japan. Both cases occurred in fishermen who became sick after fishing. They developed multiple organ failure within 20 to 36 h from the onset of initial symptoms despite intensive chemotherapy and surgical treatments.
Laboratory Confirmation of Generalized Vaccinia following Smallpox Vaccination
Authors: Kelly Cassandra D. , Egan Christina , Davis Stephen W. , Samsonoff William A. , Musser Kimberlee A. , Drabkin Peter , Miller James R. , Taylor Jill , Cirino Nick M.
Published: March 2004

The reinitiation of smallpox vaccination has renewed interest in implementing modern diagnostic methods to assess orthopoxvirus infection and adverse events following vaccination. We report here the laboratory confirmation of vaccinia virus in pustular lesions of a healthy adult vaccinee by use of a two-tier algorithm incorporating TaqMan PCR and electron microscopy.
Aspergillus fumigatus
Empyema, Arthritis, and Calcaneal Osteomyelitis in a Lung Transplant Patient Successfully Treated with Posaconazole
Authors: Lodge Barbara Alexander , Ashley Elizabeth Dodds , Steele Mark P. , Perfect John R.
Published: March 2004

A 64-year-old male with
Aspergillus fumigatus
infection that had disseminated from the lung to the ankle and adjacent bone was treated successfully with posaconazole after therapy with itraconazole and amphotericin B lipid complex failed. Marked clinical improvement occurred within 6 weeks of initiation of posaconazole therapy; after 6 months, infection had resolved at all sites. The patient has had no recurrence of infection.
Phenotypic and Genotypic Analyses of Enterohemorrhagic
Escherichia coli
O145 Strains from Patients in Germany
Authors: Sonntag Anne-Katharina , Prager Rita , Bielaszewska Martina , Zhang Wenlan , Fruth Angelika , Tschäpe Helmut , Karch Helge
Published: March 2004

Enterohemorrhagic
Escherichia coli
(EHEC) strains of serogroup O145 are emerging as causes of diarrhea and the hemolytic-uremic syndrome. However, there have been few genetic analyses of this EHEC group. We investigated the serotypes, virulence genes, plasmid profiles, pulsed-field gel electrophoresis (PFGE) patterns, and genetic variability of the
fliC
and
eae
genes in 120 EHEC O145 strains isolated from cases of hemolytic-uremic syndrome (
n
= 24) or diarrhea (
n
= 96) in Germany between 1996 and 2002. Three isolates belonged to serotype O145:H28, one to serotype O145:H25, and 116 were nonmotile (O145:H
−
). One hundred fourteen of the nonmotile strains shared
fliC
restriction fragment length polymorphism (RFLP) patterns identical to that of the O145:H28 strains. The remaining two nonmotile strains displayed a
fliC
-RFLP pattern identical to that of the O145:H25 strain. Each of the 117 strains with the
fliC
-RFLP
H28
pattern harbored
eae
γ, whereas the three strains with the
fliC
-RFLP
H25
pattern possessed
eae
β. Five different
stx
genotypes, six combinations of plasmid-encoded putative virulence genes, 29 plasmid profiles, and 47 PFGE types were identified. Strains within some of the PFGE types could be further subtyped by means of distinct plasmid profiles. These data demonstrate that the EHEC O145 serogroup is comprised of two different serotypes that possess distinct
eae
types. The heterogeneity of EHEC O145 strains at the chromosomal and plasmid level, in particular the high diversity in PFGE patterns, provides a basis for molecular subtyping of these pathogens.
Discrimination between Scrapie and Bovine Spongiform Encephalopathy in Sheep by Molecular Size, Immunoreactivity, and Glycoprofile of Prion Protein
Authors: Thuring C. M. A. , Erkens J. H. F. , Jacobs J. G. , Bossers A. , Van Keulen L. J. M. , Garssen G. J. , Van Zijderveld F. G. , Ryder S. J. , Groschup M. H. , Sweeney T. , Langeveld J. P. M.
Published: March 2004

A procedure for discrimination between scrapie and bovine spongiform encephalopathy (BSE) in sheep is of importance for establishing whether BSE has entered the sheep population. Since BSE has not yet been found in sheep at the farm level, such discrimination procedures can be developed only with experimental sheep BSE. Two distinctive molecular features of the prion protein (PrP)—molecular size and glycosylation profile—in proteinase K digests of brain stem tissue from sheep were used here; upon Western blotting, these features led to an unequivocal discrimination among natural scrapie, experimental scrapie, and experimental BSE. The higher electrophoretic mobility of PrP in sheep BSE could be best observed after deglycosylation treatment with
N
-glycosidase F. A simpler method for confirmation of this size difference involved comparison of the ratios for the binding of two monoclonal antibodies: P4 and 66.94b4. Based on epitope mapping studies with P4 and peptides, it appeared that N-terminal amino acid sequence WGQGGSH was intact only in sheep scrapie digests. Another feature typical for PrP in sheep BSE was the large fraction of diglycosylated PrP (70% or more). These data were obtained for a large group of positive sheep, consisting of 7 sheep with experimental BSE infection (genotypes: six ARQ/ARQ and one AHQ/AHQ), 48 sheep naturally infected with scrapie (six different genotypes), and 3 sheep with primary experimental scrapie infection. Routine tests of slaughter material serve well for the initial detection of both BSE and scrapie. With Western blotting as a rapid follow-up test, a 66.94b4/P4 antibody binding ratio above 1.5 is a practical indicator for serious suspicion of BSE infection in sheep.
Real-Time Reverse Transcriptase PCR Assay for Detection of Human Metapneumoviruses from All Known Genetic Lineages
Authors: Maertzdorf Jeroen , Wang Chiaoyin K. , Brown Jennifer B. , Quinto Joseph D. , Chu Marla , de Graaf Miranda , van den Hoogen Bernadette G. , Spaete Richard , Osterhaus Albert D. M. E. , Fouchier Ron A. M.
Published: March 2004

The discovery of human metapneumovirus and its implications for respiratory tract disease have emphasized the need for a sensitive, specific, and rapid assay to detect this virus in a clinical setting. It recently became clear that human metapneumovirus can be grouped into at least four genetic lineages. Previously described assays for the detection of human metapneumovirus were developed by using limited sequence information and failed to detect viruses from all four genetic lineages with comparable sensitivities. Here we describe the development and evaluation of a real-time reverse transcriptase PCR assay that detects human metapneumovirus from the four known genetic lineages with equal specificities and sensitivities.
Large Holocene landslides from Pylon Peak, southwestern British Columbia
Authors: Friele Pierre A , Clague John J
Published: March 2004

Mount Meager massif, the northernmost volcano of the Cascade volcanic belt, has been the site of very large (>107m3) landslides in the Holocene Epoch. We document two complex landslides at Pylon Peak, one of the peaks of the Mount Meager massif, about 790014C and 390014C years ago (about 8700 and 4400 calendar years ago). Together, the two landslides displaced ~ 6 × 108m3of volcanic rock from the south flank of Pylon Peak into nearby Meager Creek valley. Each landslide consisted of at least two phases, an early debris flow resulting from failure of hydrothermally altered pyroclastic rock at mid levels on the mountain and a later rock avalanche from a higher source. Both debris flows likely traveled down Meager Creek, and preliminary evidence from drilling indicates the 4400-year-old event traveled down Lillooet River into areas that are now settled and where population density is increasing rapidly. The mobility of the debris flows was due to the high content of fine, weathered volcanic sediment and the availability of sufficient water. The causes of the landslides are a wet climate and the presence of weak, hydrothermally altered volcanic rock containing abundant phreatic water on glacially oversteepened slopes. The landslides may have been triggered by earthquakes or by upwelling of magma to shallow depths within the volcano. However, they may also have occurred without specific triggers following extended periods of progressive weakening of the volcanic rocks.
A structural reappraisal of the BeardmoreGeraldton Belt at the southern boundary of the Wabigoon subprovince, Ontario, and implications for gold mineralization
Authors: Lafrance Bruno , DeWolfe Jerry C , Stott Greg M
Published: March 2004

The BeardmoreGeraldton Belt occurs along the southern margin of the Archean Wabigoon subprovince, Superior Province, Ontario. The belt consists of shear-bounded interleaved metasedimentary and metavolcanic units. The units were imbricated from 2696 to 2691 Ma during D1 thrusting and accretion of the Wabigoon, Quetico, and Wawa subprovinces. Post-accretion D2 deformation produced regional F2 folds that transposed lithological units parallel to the axial plane S2 cleavage of the folds. During D3 deformation, the folds were overprinted by a regional S3 cleavage oriented anticlockwise of F2 axial planes, and lithological contacts and S2 cleavage were reactivated as planes of shear within dextral regional shear zones that generally conform to the trend of the belt. D3 is a regional dextral transpression event that also affected the Quetico and Wawa subprovinces, south of the BeardmoreGeraldton Belt. Gold mineralization at the Leitch and MacLeod-Cockshutt mines, the two richest past-producing gold mines in the BeardmoreGeraldton Belt, is associated with D3 shear zones and folds, overprinting regional F2 folds. The plunge of the ore zones is parallel to F3 fold axes and to the intersection of D3 shear zones with F2 and F3 folds.
Stratigraphy, geochronology, and geochemistry of the Georgie River area, northwest British Columbia, and implications for mineral exploration
Authors: Evenchick Carol A , McNicoll Vicki J , Snyder Lori D
Published: March 2004

Georgie River area is underlain by greenschist facies volcanic, clastic, and plutonic rock. High precision UPb isotopic ages on zircon enable regional stratigraphic correlation by constraining the Lower to lower Middle Jurassic depositional history. A sample from pyroxene-phyric tholeiitic basalt is Upper Triassic and (or) Lower Jurassic in age; its upper age limit is constrained by a crosscutting intrusion dated at 189.8 ± 0.3 Ma. The Bulldog Creek pluton, at 193.0 ± 0.3 Ma, is significantly older than the previously reported KAr age. Hazelton Group strata include a coarse-grained volcaniclastic and volcanic unit overlain by a fine-grained clastic and bimodal volcanic flow unit. The coarse volaniclastic unit is coeval and probably cogenetic with the Outram Lake porphyry intrusion (189.7 ± 0.3 Ma) and near the top includes andesitic tuff (189.8 ± 0.6 Ma). These data constrain the age of deposition of the unit and support correlation with the Lower Jurassic Hazelton Group and members of the Texas Creek plutonic suite. Age of the fine clastic and bimodal volcanic unit is no older than the youngest detrital zircons (ca. 185 Ma) near its base. That age and the age of a rhyolite unit (176.6 ± 1.1 Ma) at the top support correlation with the Middle Jurassic Salmon River Formation of the Hazelton Group. Resolution of the litho- and chronostratigraphy of the area reveal close similarities in age, rock types, succession, and composition with strata that host the base- and precious metal-rich stratiform Eskay Creek deposit, revealing the potential for Eskay-type volcanogenic massive sulphide (VMS) deposits in the Georgie River area.
Pleistocene volcanic damming of Yukon River and the maximum age of the Reid Glaciation, west-central Yukon
Authors: Huscroft Crystal A , Ward Brent C , Barendregt René W , Jackson Jr. Lionel E , Opdyke Neil D
Published: March 2004

Stratigraphic, paleomagnetic, and radioisotope investigations of the Selkirk Volcanic Group have identified a new eruptive period and constrained the age of the Reid Glaciation, the most extensive middle Pleistocene cordilleran advance recognized in central Yukon. Downstream from Fort Selkirk, a complex of valley-filling compound pahoehoe basalt flows and pillow basalt is exposed for 10 km along the Yukon River and is overlain by outwash deposited during the Reid Glaciation. The flows have an 40Ar/39Ar age of 311 ± 32 ka. This age is consistent with the normal magnetization of the flows and their termination below the level of the contemporary Yukon River flood plain. Taken with the ca. 190 ka Sheep Creek tephra, which overlies Reid drift elsewhere in Yukon Territory, the Reid Glaciation is constrained to oxygen isotope stage 8, not stage 6 as previously thought. The presence of thick foreset-bedded pillow breccia units intercalated with the subaerial flows indicates that this eruption caused damming of the Yukon River. Reevaluation of the stratigraphy of early Pleistocene basalt flows and pillow lavas in the Fort Selkirk area indicates that volcanic damming of the Yukon River has occurred at least once previously.
Seasonal and ontogenetic patterns in the migration of anadromous brook charr (Salvelinus fontinalis)
Authors: Lenormand Sophie , Dodson Julian J , Ménard Annie
Published: March 2004

Migration patterns of brook charr (Salvelinus fontinalis) from the Sainte-Marguerite River, Québec, Canada, were investigated to explore the hypothesis that migratory behaviour changes according to size during the critical period of first downstream migration, when survival is likely to be related to size, and during subsequent seasonal movements. We hypothesized that as fish grow, they should adopt more conservative behaviours to protect the reproductive assets that they have accumulated. First downstream migration occurred over a month in spring. Larger juvenile charr migrated early, whereas smaller charr seemed to delay offshore migration. As predicted, migratory patterns of charr changed through ontogeny. Sea age 0 juveniles stayed in estuarine areas until October and overwintered outside their natal river. Sea age 1 juveniles returned to their natal river earlier in the fall and some of them overwintered there. Adults (some sea age 1 migrants and older migrants) undertook their upstream migration to spawning areas from July to September, larger ones migrating earlier than smaller ones. Postspawners migrated downstream after reproduction or overwintered in the river. Environmental differences related to geographical location may be responsible for the variation of migration patterns and other life-history traits observed among brook charr populations, emphasizing the co-evolution of anadromy and life history.
An analysis of homogenization and differentiation of Canadian freshwater fish faunas with an emphasis on British Columbia
Authors: Taylor Eric B
Published: March 2004

Faunal homogenization and differentiation occur when geographic regions show increased or decreased, respectively, similarity to each other in species composition owing to introductions and extinctions or extirpations. I used species presenceabsence data for "native" (i.e., estimated species compositions before European settlement) and "total" (i.e., including nonnative fishes and extinctions) faunas to examine faunal similarity of freshwater fishes among aquatic ecoregions of British Columbia and among Canadian provinces and territories. British Columbia ecoregions showed faunal differentiation as the mean Jaccard's faunal similarity coefficient for total faunas was significantly less than that for native faunas (31.4% versus 34.9%), but some ecoregions showed homogenization (e.g., Vancouver Island and Columbia River ecoregions). Comparisons across Canada showed low but significant homogenization; average pairwise Jaccard's coefficient was higher in total versus native faunas (29.1% similarity versus 27.8%, respectively). British Columbia's fish fauna increased the most in similarity to other areas (except the three territories), with an average increase of 4.9%. Native faunal similarity patterns are part of Canada's natural heritage but are threatened by human-mediated increases in nonnative species and extinctions. This analysis provides a baseline to track changes in inter regional faunal relationships at different geographic scales.
Temperature and salinity effects on strontium incorporation in otoliths of larval spot (Leiostomus xanthurus)
Authors: Martin Gretchen Bath , Thorrold Simon R , Jones Cynthia M
Published: March 2004

Temperature dependence of strontium/calcium (Sr/Ca) ratios in foraminiferal calcite and coral aragonite is well established; however, factors controlling Sr/Ca ratios in fish otoliths remain obscure. To assess temperature dependence of Sr/Ca in marine fish otoliths, we reared spot (Leiostomus xanthurus) larvae under controlled temperature (1726 °C) and salinity (15 and 25). We found a significant linear relationship between temperature and Sr/Ca ratios, with a sensitivity of approximately 5%·°C1. Otolith Sr/Ca values were also significantly higher at a salinity of 25 vs. 15, after accounting for differences in dissolved Sr/Ca ratios in the ambient water, with a sensitivity of approximately 1%/salinity (). These observations complicate the use of Sr/Ca ratios to determine temperature histories of spot larvae, because accurate temperature reconstructions are possible only with a priori knowledge of both ambient salinity and dissolved Sr/Ca ratios. Fully marine species residing in oceanic waters will not experience significant salinity variations; therefore, otolith Sr/Ca ratios may be useful recorders of temperature exposure. Otolith Sr/Ca thermometry in coastal fish species that make regular excursions into estuarine waters will be more problematic. Multiple geochemical tracers, including oxygen stable isotopes and other trace elements, may be necessary to accurately reconstruct temperature and salinity histories in these species.
The wave-drag hypothesis: an explanation for size-based lateral segregation during the upstream migration of salmonids
Authors: Hughes Nicholas F
Published: March 2004

During their spawning migration, large salmon, e.g., chinook (Oncorhynchus tshawytscha), swim upstream further from the bank than smaller ones, e.g., sockeye (Oncorhynchus nerka). This pattern is counterintuitive because natural selection should favor behavior that minimizes migration costs, yet by traveling further from the bank, large fish will have to swim against faster currents. Existing theory predicts that they will expend more energy than necessary as a result. One explanation for this apparently paradoxical behavior is that large fish swim further from the bank to avoid wave drag, the resistance associated with the generation of surface waves when swimming close to the surface. Wave drag was incorporated into existing theory, and the resulting model was tested to determine whether it explained size-based lateral segregation of chinook and sockeye salmon in the Nushagak River, Alaska. The wave-drag model accurately predicted the migration corridor for both species. Existing theory worked well for sockeye but not for chinook. The key to these predictions is that wave drag scales according the ratio of maximum body diameter to submergence depth, so bigger fish need to swim deeper to escape its effects.
Variation in neutral and polar lipid compositions of ova in ten reproductively isolated populations of walleye (Sander vitreus)
Authors: Wiegand Murray D , Johnston Thomas A , Martin Jennifer , Leggett William C
Published: March 2004

We examined variation in the mass and composition of egg lipids within and among 10 walleye (Sander vitreus) populations. Larger eggs contained more lipid, but neither absolute lipid content (mg·egg1) nor relative lipid content (percent of egg mass as lipid) were related to maternal age or size. Among populations, the proportion of egg mass as neutral lipid varied significantly, whereas the proportion as polar lipid did not. Egg fatty acid composition did vary with respect to maternal traits. In the Lake Ontario population, larger females appear to produce a qualitatively superior egg; relative abundances of docosahexaenoic acid (22:6(n3), DHA) and arachidonic acid (20:4(n6), AA) increased, and the relative abundance of eicosapentaenoic acid (20:5(n3), EPA) decreased in egg fatty acids with increasing maternal length. We predicted that fatty acid profiles would be less variable in the polar than in the neutral lipid fraction. Relative abundances of DHA, AA, the sum of AA and EPA, and several other fatty acid classes were all significantly less variable in the polar than in the neutral fraction both among females and among populations. Our results indicate a high level of conservatism of egg lipid mass and polar lipid composition in this species.
An analysis of error structure in modeling the stockrecruitment data of gadoid stocks using generalized linear models
Authors: Jiao Yan , Schneider David , Chen Yong , Wroblewski Joe
Published: March 2004

When modeling the stockrecruitment (SR) relationship, the Cushing, Ricker, and other SR models are fitted to the observed SR data by estimating parameters with assumptions made concerning the model error structure. Using a generalized linear model approach, we explored and identified the appropriate model error structure in modeling SR data for gadoid stocks. The SR parameter estimation was found to be influenced by the choice of error distributions assumed in the analysis. In modeling SR data for gadoid stocks, the BevertonHolt model was found to be more sensitive to the assumption of model error distribution than the Cushing and Ricker models. The lognormal and gamma distributions had higher probability of being acceptable model error distributions. Cluster analyses and summary statistics of error distributions in SR modeling did not show consistent patterns in the identification of an acceptable model error structure among species, geographic distributions, and sample sizes. A better understanding of the factors and mechanisms resulting in differences in the choice of appropriate model error distributions for different populations is needed in future research. We recommend that the generalized linear model be used to identify acceptable model error structures in quantifying SR relationships.
A simulation study of impacts of error structure on modeling stockrecruitment data using generalized linear models
Authors: Jiao Yan , Chen Yong , Schneider David , Wroblewski Joe
Published: March 2004

Stockrecruitment (SR) models are commonly fitted to SR data with a least-squares method. Errors in modeling are usually assumed to be normal or lognormal, regardless of whether such an assumption is realistic. A Monte Carlo simulation approach was used to evaluate the impact of the assumption of error structure on SR modeling. The generalized linear model, which can readily deal with different error structures, was used in estimating parameters. This study suggests that the quality of SR parameter estimation, measured by estimation errors, can be influenced by the realism of error structure assumed in an estimation, the number of SR data points, and the number of outliers in modeling. A small number of SR data points and the presence of outliers in SR data could increase the difficulty in identifying an appropriate error structure in modeling, which might lead to large biases in the SR param eter estimation. This study shows that generalized linear model methods can help identify an appropriate error distribution in SR modeling, leading to an improved estimation of parameters even when there are outliers and the number of SR data points is small. We recommend the generalized linear model be used for quantifying stockrecruitment relationships.
Water quality and disinfection impact of ClO2 contamination by free chlorine: A case study
Authors: Hofmann Ron , Andrews Robert C , Ranger Georges
Published: March 2004

A bench-scale study was conducted using water from a drinking water treatment facility on Lake Ontario to investigate water quality and disinfection impacts of chlorine contamination in a chlorine dioxide solution applied for primary disinfection. Levels of chlorine contamination were varied between 0% (pure chlorine dioxide) and 20%, with a chlorine dioxide dose of 1 mg/L. The chlorine did not significantly affect the rate of chlorine dioxide decay in the water. The chlorine reduced chlorite formation, but led to a corresponding increase in chlorate formation. Trihalomethane and haloacetic acid concentrations varied with the amount of free chlorine present in the chlorine dioxide solution. Levels of Bacillus subtilis endospore inactivation were similar for solutions containing pure chlorine dioxide and a 20%:80% chlorine:chlorine dioxide mass ratio (for the same total chlorine concentration). Since chlorine alone has been reported to be very ineffective against these endospores, the results suggest that the disinfection effectiveness of the mixture was greater than the effectiveness predicted from each of the two disinfectants acting alone. Key words: chlorine dioxide, chlorine, disinfection, by-products, inactivation, drinking water.
Analysis of wind-driven resuspension of metal mine sludge in a tailings pond
Authors: Mian M Haneef , Yanful Ernest K
Published: March 2004

Shallow water covers, typically less than 2 m deep, are commonly used to store tailings and minimize environmental degradation. Studies have, however, shown that wind induced waves can erode and resuspend tailings in areas where the water cover is much shallower than 1 m, possibly leading to oxidation of sulphide minerals, acid generation, and release of heavy metals. The present work investigated erosion and resuspension of co-disposed, cohesive mill tailings and lime neutralization sludge in a tailings pond located at the Heath Steele mine site, near Miramichi, New Brunswick, Canada. From measured wind data and published equations, suspended sediment concentrations were modeled for various water cover depths and compared to measured total suspended solids (TSS) values and the federal effluent discharge guideline of 25 mg L–1. The computed suspended sediment concentrations agreed with those measured at the effluent discharge point. The results show that winds blowing in the direction of the major axis of the pond contributed most to resuspension and elevated TSS. Key words: cohesive mine tailings and sludge, critical shear stress, wind-induced resuspension, effluent water quality.
Synthesis and conformations of phosphine- and phosphinite-derivatized resorcinarenes
Authors: Eisler Dana J , Puddephatt Richard J
Published: March 2004

The synthesis of resorcinarene derivatives with four or eight alkynyldiphenylphosphine or diphenyl phosphinite functional groups is reported. The tetraphosphinite derivatives have effective C2v symmetry and have the potential to adopt two different boat conformations in which the arene groups with phosphinite substituents are horizontal or vertical. A method for the determination of the solution-state conformation of the resorcinarene skeleton using correlated 1H and 13C NMR data is reported, and the boat conformation of one tetraphosphinite compound in the solid state has been determined crystallographically.Key words: phosphine, phosphinite, resorcinarene, conformation.
The β-(acyloxy)alkyl radical rearrangement revisited
Authors: Crich David , Suk Dae-Hwan
Published: March 2004

A β-(acyloxy)alkyl radical precursor, containing a carboxylate residue suitably placed for the trapping of any intermediate alkene radical cations, has been constructed. In nonpolar solutions the probe, in the form of either the free acid or its tetrabutylammonium salt, undergoes the typical rearrangement reaction with no evidence of trapping, leading to the conclusion that the reaction is either concerted or that collapse of any intermediate contact ion pair is so rapid as to preclude the possibility of trapping.Key words: radical, rearrangement, contact ion pair.
A new family of monocyclopentadienyl organoscandium bis-alkyls supported by a bulky trialkylphosphine oxide ancillary
Authors: Henderson Lee D , MacInnis Glen D , Piers Warren E , Parvez Masood
Published: March 2004

Treatment of the oligomeric compound [Cp*ScCl2]n (Cp* = C5Me5) with tri-tert-butylphosphine oxide in THF leads to the monocyclopentadienyl scandium dichloride [Cp*(t-Bu3P=O)ScCl2] as a monomeric, THF-free solid in 72% yield. This compound can be alkylated with MeLi to give the corresponding dimethyl derivative, [Cp*(t-Bu3P=O)ScMe2], 1. The crystal structures of these two compounds have been done and reveal a three-legged piano stool geometry about the scandium center. The coordinated phosphine oxide ligand exchanges with free donor in both compounds via an associative mechanism, as indicated by the activation parameters (ΔH = 6.48.4 kcal mol1-; ΔS = 22.5 to 26.6 eu). Thus, the Cp*(t-Bu3P=O) ligand set provides a stable platform for organoscandium chemistry. This was demonstrated by the activation of 1 by treatment with B(C6F5)3 to form the fully characterized contact ion pair [Cp*(t-Bu3P=O)ScMe]+[MeB(C6F5)3], 2, which is an active ethylene polymerization catalyst.Key words: organoscandium compounds, olefin polymerization, cationic complexes.
Nucleophilic additions of lactam-derived enol triflates to aldehydes mediated by nickel(II) and chromium(II) salts
Authors: Easton Leah P , Dake Gregory R
Published: March 2004

Enol trifluoromethanesulfonates (triflates) derived from N-protected lactams undergo nickel(II)-chloride- and chromium(II)-chloride-promoted carbonyl additions to aldehydes. The yields of this process range from 42%84%.Key words: nickel(II) chloride, chromium(II) chloride, carbonyl addition, lactam-derived enol triflate.
Diastereoselective reduction of α-aminoketones: Synthesis of anti- and syn-β-aminoalcohols
Authors: Fraser David S , Park Sheldon B , Chong J Michael
Published: March 2004

Reduction of N-t-BOC-protected-N-alkyl α-aminoketones with LiEt3BH or Li(s-Bu)3BH furnishes protected syn-β-aminoalcohols with high selectivities. In contrast, removal of the BOC group followed by reduction of the aminoketone gives anti-β-aminoalcohols with variable selectivities. With aromatic ketones, selectivities are typically high while aliphatic ketones show mediocre to high selectivities depending on steric considerations.Key words: β-aminoalcohol, diastereoselective reduction.
Diastereoselectivity in asymmetric allylations: The role of vicinal chirality in the allyl nucleophile for SE2′ reactions with aldehydes
Authors: Williams David R , Meyer Kevin G , Shamim Khalida , Patnaik Samarjit
Published: March 2004

A series of nonracemic homoallylic alcohols have been prepared by asymmetric allylation using the (R,R)- and (S,S)-1,2-diamino-1,2-diphenylethane bis-sulfonamide controller ligands for in situ formation of chiral B-allyl-1,3,2-diazaborolidines. Diastereofacial selectivity is influenced by adjacent stereochemistry incorporated into the allyl moiety at C-2, in addition to the expected role of the chiral auxiliary. Additional asymmetry in the aldehyde reactant introduces threefold stereodifferentiation. A model is developed to identify reinforcing stereochemical relationships, and examples have ascertained the relative significance of these factors. The methodology supports the construction of complex homoallylic alcohols in a highly convergent fashion.Key words: asymmetric allylation, diastereofacial selectivity, 1,4-stereocontrol, homoallylic alcohols.
Synthesis, resolution, and application of 2,2′-bis(diphenylphosphino)-3,3′-binaphtho[b]furan (BINAPFu)
Authors: Andersen Neil G , Parvez Masood , McDonald Robert , Keay Brian A
Published: March 2004

(±)-2,2′-Bis(diphenylphosphino)-3,3′-binaphtho[2,1-b]furan (BINAPFu) was synthesized from 2-naphthoxyacetic acid in a five-step sequence in 62% overall yield. A variety of reported resolution procedures for biaryl bisphosphines did not work with (±)-BINAPFu; thus, a new resolution method was developed, involving the Staudinger reaction of the aforementioned racemate of BINAPFu with an enantiopure camphor sulfonyl azide derivative. The resulting diastereomeric phosphinimines were separated by flash chromatography. Subsequent hydrolysis to the corresponding bis-phosphine oxide and trichlorosilane reduction provided enantiopure BINAPFu. The absolute stereochemical configuration of BINAPFu was established by X-ray crystallography. BINAPFu was compared with commercially available 2,2′-bis(diphenylphosphino)-1,1′-binaphthalene (BINAP) in Pd(0)-catalyzed intermolecular Heck reactions. Investigation of the Heck arylation of 2,3-dihydrofuran showed BINAPFu to be more efficacious than BINAP in dioxane at 30 °C. A variety of phosphorus selenides were prepared, and the 1JP-Se coupling constants measured, to obtain a comparative scale of parent phosphine basicity. The phosphorus atoms in BINAPFu were found to be electron deficient when compared with BINAP but slightly more electron rich than trifurylphosphine. Key words: naphthofurans, atropisomers, electron-deficient phosphines, asymmetric Heck reactions, Staudinger reaction.
Kinetics and mechanism of the oxidation ofL-α-amino-n-butyric acid in moderately concentrated sulfuric acid medium
Authors: Bahrami Homayoon , Zahedi Mansour
Published: March 2004

The reaction kinetics of L-α-amino-n-butyric acid oxidation by permanganate ion have been investigated in moderately strong acid medium using a spectrophotometric technique. In all cases studied an autocatalytic effect, due to Mn+2ions formed as a reaction product, was observed. Both catalytic and noncatalytic processes were determined to be first order with respect to the permanganate ion and the amino acid. The overall rate equation for this process may be written as: [Formula: see text]

where k′1and k′2are pseudo-order rate constants for the noncatalytic and catalytic reactions, respectively. The influence of some factors such as temperature and reactant concentration on the rate constants has been studied, and the activation parameters have been calculated. Reaction mechanisms satisfying observations for both catalytic and noncatalytic routes have been presented.Key words: L-α-amino-n-butyric acid, permanganate oxidation, concentrated acidic medium, autocatalysis, free radical intermediates.
An iterative approach to three fragments of ionomycin
Authors: Spino Claude , Allan Martin
Published: March 2004

The SN2′ displacement of menthone-derived allylic carbonates with cuprate reagents occurs with high diastereoselectivity. This method can be used in an iterative fashion to construct stereocenters bearing a 1,3-relationship in a carbon chain. Each iteration provides the adduct in greater than 99% de. The synthesis of three fragments of the polyether ionophore ionomycin is disclosed.Key words: menthone, chiral auxiliary, SN2′ displacement, cuprate, iteration, ionomycin.