bluuebunny/crossref_metadata_2025_split huggingface dataset:
Aerodynamic Characteristics of the Crest with Membrane Attachment on Cretaceous Pterodactyloid Nyctosaurus
Authors: XING Lida , WU Jianghao , LU Yi , LÜ Junchang , JI Qiang 
Published: February 2009

Abstract:The Nyctosaurus specimen KJ1 was reconstructed under the hypothesis that there is a membrane attached to the crest; the so‐called headsail crest. The aerodynamic forces and moment acting on the headsail crest were analyzed. It was shown that KJ1 might adjust the angle of the headsail crest relative to the air current as one way to generate thrust (one of the aerodynamic forces, used to overcome body drag in forward flight) and that the magnitude of the thrust and moment could vary with the gesture angle and the relative location between the aerodynamic center of the headsail crest and body's center of gravity. Three scenarios were tested for comparison: the crest with membrane attachment, the crest without membrane attachment and the absence of a cranial crest. It was shown that the aerodynamic characteristics (increasing, maintaining and decreasing thrusts and moment) would have almost disappear in flight for the crest without membrane attachment and was non‐existent without the cranial crest. It is suggested from aerodynamics evidence alone that Nyctosaurus specimen KJ1 had a membrane attached to the crest and used this reconstructed form for auxiliary flight control.
Revision of the Clam Shrimp Genus Magumbonia from the Upper Jurassic of the Luanping Basin, Hebei, Northern China
Authors: LI Gang , SHEN Yanbin , LIU Yongqing , BENGTSON Peter , WILLEMS Helmut , HIRANO Hiramichi 
Published: February 2009

Abstract:The diverse clam shrimp Nestoria‐Keratestheria fauna is widely distributed in the Dabeigou Formation in northern Hebei and eastern Inner Mongolia of China. Its important component genus Magumbonia from the Dabeigou Formation in the Luanping Basin, northern Hebei, China, is revised on the basis of a scanning electron microscope (SEM) examination of the type species M. jingshangensis Wang, 1984, which revealed morphological features not recognized previously. These include coarse reticulation on the umbo and prominent growth lines ornamented with densely spaced, small tubercles and fine lirae.
Phase Equilibria of Hornblende‐Bearing Eclogite in the Western Dabie Mountain, Central China
Authors: ZHANG Jingsen , WEI Chunjing , LOU Yuxing , SU Xiangli 
Published: February 2009

Abstract:The high‐pressure (HP) eclogite in the western Dabie Mountain encloses numerous hornblendes, mostly barroisite. Opinions on the peak metamorphic P‐T condition, PT path and mineral paragenesis of it are still in dispute. Generally, HP eclogite involves garnet, omphacite, hornblendes and quartz, with or without glaucophane, zoisite and phengite. The garnet has compositional zoning with XMg increase, XCa and XMn decrease from core to rim, which indicates a progressive metamorphism. The phase equilibria of the HP eclogite modeled by the P‐T pseudosection method developed recently showed the following: (1) the growth zonation of garnet records a progressive metamorphic PT path from pre‐peak condition of 1.9–2.1 GPa at 508°C‐514°C to a peak one of 2.3–2.5 GPa at 528°C‐531°C for the HP eclogite; (2) the peak mineral assemblage is garnet+omphacite+glaucophane+quartz±phengite, likely paragenetic with lawsonite; (3) the extensive hornblendes derive mainly from glaucophane, partial omphacite and even a little garnet due to the decompression with some heating during the post‐peak stage, mostly representing the conditions of about 1.4–1.6 GPa and 580°C‐640°C, and their growth is favored by the dehydration of lawsonite into zoisite or epidote, but most of the garnet, omphacite or phengite in the HP eclogite still preserve their compositions at peak condition, and they are not obviously equilibrious with the hornblendes.
Structural Characteristics and Formation Mechanism in the Micangshan Foreland, South China
Authors: XU Huaming , LIU Shu , QU Guosheng , LI Yanfeng , SUN Gang , LIU Kang 
Published: February 2009

Abstract:Lying at the junction of the Dabashan, Longmenshan and Qinling mountains, the Micangshan Orogenic Belt coupled with a basin is a duplex structure and back‐thrust triangular belt with little horizontal displacement, small thrust faults and continuous sedimentary cover. On the basis of 3D seismic data, and through sedimentary and structural research, the Micangshan foreland can be divided into five subbelts, which from north to south are: basement thrust, frontal thrust, foreland depression‐back‐thrust triangle, foreland fold belt or anticline belt, and the Tongjiang Depression. Along the direction of strike from west to east, the arcuate structural belt of Micangshan can be divided into west, middle and east segments. During the collision between the Qinling and Yangtze plates, the Micangshan Orogenic Belt was subjected to the interaction of three rigid terranes: Bikou, Foping, and Fenghuangshan (a.k.a. Ziyang) terranes. The collision processes of rigid terranes controlled the structural development of the Micangshan foreland, which are: (a) the former collision between the Micangshan‐Hannan and Bikou terranes forming the earlier rudiments of the structure; and (b) the later collision forming the main body of the structural belt. The formation processes of the Micangshan Orogenic Belt can be divided into four stages: (1) in the early stage of the Indosinian movement, the Micangshan‐Hannan Rigid Terrane was jointed to the Qinling Plate by the clockwise subduction of the Yangtze Plate toward the Qinling Plate; (2) since the late Triassic, the earlier rudiments of the Tongnanba and Jiulongshan anticlines and corresponding syncline were formed by compression from different directions of the Bikou, Foping and Micangshan‐Hannan terranes; (3) in the early stage of the Himalayan movement, the Micangshan‐Hannan Terrane formed the Micangshan Nappe torwards the foreland basin and the compression stresses were mainly concentrated along both its flanks, whereas the Micangshan‐Hannan Terrane wedged into the Qinling Orogenic Belt with force; (4) in the late stage of the Himalayan movement, the main collision of the Qinling Plate made the old basement rocks of the terrane uplift quickly, to form the Micangshan Orogenic Belt. The Micangshan foreland arcuate structure was formed due to the non‐homogeneity of terrane movement.
CAD/CAM to fabricate ceramic implant abutments and crowns: a preliminary in vitro study
Authors: Alfarsi MA , Okutan H Mehmet , Bickel M 
Published: February 2009

AbstractBackground:  This study evaluated the feasibility of fabricating implant abutments and crowns from pre‐sintered feldspathic porcelain blocks using the chair‐side CAD/CAM, CEREC3D® system.Methods:  Thirty‐two implant analogues were divided into two groups. In the control group, prefabricated machined anatomical titanium (Ti) abutments were screw‐retained to the analogues. In the test group, machined feldspathic porcelain abutments were cemented on prefabricated machined Ti links and screw‐retained to the implant analogues. These feldspathic porcelain abutments were fabricated out of pre‐sintered feldspathic porcelain blocks as duplicates of the abutments in the control group using the CAD/CAM, CEREC3D® system. Thirty‐two feldspathic porcelain crowns, also fabricated out of pre‐sintered ceramic blocks, were then cemented with resin cement on all the abutments in both groups. All samples were subsequently subjected to fracture strength testing under static load. An unpaired t‐test was used to compare fracture load values between the two groups.Results:  The test group using feldspathic porcelain abutments and crowns showed statistically significant higher mean fracture strength than the control group with the Ti abutments and feldspathic porcelain crowns.Conclusions:  This preliminary study showed that the chair‐side CAD/CAM technology can be utilized to fabricate customized ceramic abutments with their associated ceramic crowns using pre‐sintered feldspathic porcelain blocks.
Clinical detection of caries in the primary dentition with and without bitewing radiography
Authors: Newman B , Seow WK , Kazoullis S , Ford D , Holcombe T 
Published: February 2009

AbstractBackground:  Inadequate detection of caries in the primary dentition due to non‐use of bitewing radiography is commonly encountered in paediatric practice. The present study investigated the increased benefits of using bitewing radiography in addition to the visual‐tactile examination technique for detection of primary dentition caries in a non‐fluoridated community, and determined the prevalence of “hidden” occlusal caries in the primary dentition.Methods:  Primary teeth were scored for caries at the restorative threshold using a visual‐tactile technique followed by bitewing radiographic examination in a sample of 611 schoolchildren aged 6.4 ± 0.5 yrs to 12.1 ± 0.8 yrs residing in a non‐fluoridated city.Results:  Overall, at the restorative threshold, the visual‐tactile technique could detect 62 per cent of occlusal caries compared to 74 per cent for bitewing radiography (p < 0.001). The prevalence of “hidden” occlusal caries was 12 per cent. In contrast, for primary molar proximal surface caries, the visual‐tactile technique could detect only 43 per cent of caries compared with 91 per cent for bitewing radiography (p < 0.001).Conclusions:  In the primary dentition, use of bitewing radiography increases the detection rate of proximal surface caries substantially. It is recommended that bitewing radiography be included as part of the routine examination of children with proximal surfaces that cannot be visualized.
Rotational drift of mandibular third molar teeth: a series of four cases
Authors: Hughes AJ , Vudiniabola ST , McMillan BD , Smith AC 
Published: February 2009

AbstractRotational drift of mandibular third molar teeth is a challenge for clinicians to predict and manage. Evidence on the incidence and degree of rotation is sparse. As the factors influencing rotation are not defined, prediction is impossible. A series of four cases with lower third molar rotation are presented and discussed. Significant rotation can alter the degree of difficulty for an extraction. A lack of well‐documented cases has hindered investigation of this phenomenon. Further research is required to identify the aetiology, incidence and increase in risk factors caused by such rotational drift.
A Transferable 20-Kilobase Multiple Drug Resistance-Conferring R Plasmid (pKL0018) from a Fish Pathogen (
Lactococcus garvieae
) Is Highly Homologous to a Conjugative Multiple Drug Resistance-Conferring Enterococcal Plasmid
Authors: Maki Takeshi , Santos Mudjekeewis D. , Kondo Hidehiro , Hirono Ikuo , Aoki Takashi 
Published: February 2009

ABSTRACT

Lactococcus garvieae
, the causative agent of lactococcosis, has evolved strains that are highly resistant to antibiotics. Here, the 20,034-bp sequence of
L. garvieae
conjugative plasmid pKL0018 was determined. It contained two
erm
B genes and one
tet
S gene and a backbone more than 96% identical to that of pRE25, an
Enterococcus faecalis
plasmid from dry sausage.
Formation of Multilayered Photosynthetic Biofilms in an Alkaline Thermal Spring in Yellowstone National Park, Wyoming
Authors: Boomer Sarah M. , Noll Katherine L. , Geesey Gill G. , Dutton Bryan E. 
Published: February 2009

ABSTRACT

In this study, glass rods suspended at the air-water interface in the runoff channel of Fairy Geyser, Yellowstone National Park, WY, were used as a substratum to promote the development of biofilms that resembled multilayered mat communities in the splash zone at the geyser's source. This approach enabled the establishment of the temporal relationship between the appearance of
Cyanobacteria
, which ultimately formed the outer green layer, and the development of a red underlayer containing
Roseiflexus
-like
Chloroflexi
. This is the first study to define time-dependent successional events involved in the development of differently colored layers within microbial mats associated with many thermal features in Yellowstone National Park. Initial (1-month) biofilms were localized below the air-water interface (60 to 70°C), and the majority of retrieved bacterial sequence types were similar to
Synechococcus
and
Thermus
isolates. Biofilms then shifted, becoming established at and above the air-water interface after 3 months. During winter sampling (6 to 8 months), distinct reddish orange microcolonies were observed, consistent with the appearance of
Roseiflexus
-like sequences and bacteriochlorophyll
a
pigment signatures. Additionally, populations of
Cyanobacteria
diversified to include both unicellular and filamentous cell and sequence types. Distinct green and red layers were observed at 13 months.
Planctomycetes
-like sequences were also retrieved in high abundance from final biofilm layers and winter samples. Finally, biomass associated with geyser vent water contained
Roseiflexus
-like sequence types, in addition to other high-abundance sequence types retrieved from biofilm samples, supporting the idea that geothermal water serves as an inoculum for these habitats.
Production of the Phytohormone Indole-3-Acetic Acid by Estuarine Species of the Genus
Vibrio
Authors: Gutierrez Casandra K. , Matsui George Y. , Lincoln David E. , Lovell Charles R. 
Published: February 2009

ABSTRACT

Strains of
Vibrio
spp. isolated from roots of the estuarine grasses
Spartina alterniflora
and
Juncus roemerianus
produce the phytohormone indole-3-acetic acid (IAA). The colorimetric Salkowski assay was used for initial screening of IAA production. Gas chromatography-mass spectroscopy (GC-MS) was then employed to confirm and quantify IAA production. The accuracy of IAA quantification by the Salkowski assay was examined by comparison to GC-MS assay values. Indole-3-acetamide, an intermediate in IAA biosynthesis by the indole-3-acetamide pathway, was also identified by GC-MS. Multilocus sequence typing of concatenated 16S rRNA,
recA
, and
rpoA
genes was used for phylogenetic analysis of environmental isolates within the genus
Vibrio
. Eight
Vibrio
type strains and five additional species-level clades containing a total of 16 environmental isolates and representing five presumptive new species were identified as IAA-producing
Vibrio
species. Six additional environmental isolates similar to four of the
Vibrio
type strains were also IAA producers. To our knowledge, this is the first report of IAA production by species of the genus
Vibrio
or by bacteria isolated from an estuarine environment.
A Novel
Dehalobacter
Species Is Involved in Extensive 4,5,6,7-Tetrachlorophthalide Dechlorination
Authors: Yoshida Naoko , Ye Lizhen , Baba Daisuke , Katayama Arata 
Published: February 2009

ABSTRACT

The purpose of this study was the enrichment and phylogenetic identification of bacteria that dechlorinate 4,5,6,7-tetrachlorophthalide (commercially designated “fthalide”), an effective fungicide for rice blast disease. Sequential transfer culture of a paddy soil with lactate and fthalide produced a soil-free enrichment culture (designated the “KFL culture”) that dechlorinated fthalide by using hydrogen, which is produced from lactate. Phylogenetic analysis based on 16S rRNA genes revealed the dominance of two novel phylotypes of the genus
Dehalobacter
(FTH1 and FTH2) in the KFL culture. FTH1 and FTH2 disappeared during culture transfer in medium without fthalide and increased in abundance with the dechlorination of fthalide, indicating their growth dependence on the dechlorination of fthalide.
Dehalobacter restrictus
TEA is their closest relative, with 97.5% and 97.3% 16S rRNA gene similarities to FTH1 and FTH2, respectively.
Isolation and Characterization of Metalloproteases with a Novel Domain Structure by Construction and Screening of Metagenomic Libraries
Authors: Waschkowitz Tanja , Rockstroh Stephanie , Daniel Rolf 
Published: February 2009

ABSTRACT

Small-insert metagenomic libraries from four samples were constructed by a topoisomerase-based and a T4 DNA ligase-based approach. Direct comparison of both approaches revealed that application of the topoisomerase-based method resulted in a higher number of insert-containing clones per μg of environmental DNA used for cloning and a larger average insert size. Subsequently, the constructed libraries were partially screened for the presence of genes conferring proteolytic activity. The function-driven screen was based on the ability of the library-containing
Escherichia coli
clones to form halos on skim milk-containing agar plates. The screening of 80,000
E. coli
clones yielded four positive clones. Two of the plasmids (pTW2 and pTW3) recovered from positive clones conferred strong proteolytic activity and were studied further. Analysis of the entire insert sequences of pTW2 (28,113 bp) and pTW3 (19,956 bp) suggested that the DNA fragments were derived from members of the genus
Xanthomonas
. Each of the plasmids harbored one gene (2,589 bp) encoding a metalloprotease (
mprA
, pTW2;
mprB
, pTW3). Sequence and biochemical analyses revealed that MprA and MprB are similar extracellular proteases belonging to the M4 family of metallopeptidases (thermolysin-like family). Both enzymes possessed a unique modular structure and consisted of four regions: the signal sequence, the N-terminal proregion, the protease region, and the C-terminal extension. The architecture of the latter region, which was characterized by the presence of two prepeptidase C-terminal domains and one proprotein convertase P domain, is novel for bacterial metalloproteases. Studies with derivatives of MprA and MprB revealed that the C-terminal extension is not essential for protease activity. The optimum pH and temperature of both proteases were 8.0 and 65°C, respectively, when casein was used as substrate.
Effect of Biowaste Sludge Maturation on the Diversity of Thermophilic Bacteria and Archaea in an Anaerobic Reactor
Authors: Goberna M. , Insam H. , Franke-Whittle I. H. 
Published: February 2009

ABSTRACT

Prokaryotic diversity was investigated near the inlet and outlet of a plug-flow reactor. After analyzing 800 clones, 50 bacterial and 3 archaeal phylogenetic groups were defined.
Clostridia
(>92%) dominated among bacteria and
Methanoculleus
(>90%) among archaea. Significant changes in pH and volatile fatty acids did not invoke a major shift in the phylogenetic groups. We suggest that the environmental filter imposed by the saline conditions (20 g liter
−1
) selected a stable community of halotolerant and halophilic prokaryotes.
Community Composition and Density of Methanogens in the Foregut of the Tammar Wallaby (Macropus eugenii)
Authors: Evans Paul N. , Hinds Lyn A. , Sly Lindsay I. , McSweeney Christopher S. , Morrison Mark , Wright André-Denis G. 
Published: February 2009

ABSTRACTThe composition of the methanogenic archaeal community in the foregut contents of Tammar wallabies (Macropus eugenii) was studied using 16S rRNA and methyl coenzyme reductase subunit A (mcrA) gene clone libraries. Methanogens belonging to theMethanobacterialesand a well-supported cluster of uncultivated archaeon sequences previously observed in the ovine and bovine rumens were found. Methanogen densities ranged from 7.0 × 105and 3.9 × 106cells per gram of wet weight.
Seasonal Dynamics and Metagenomic Characterization of Estuarine Viriobenthos Assemblages by Randomly Amplified Polymorphic DNA PCR
Authors: Helton Rebekah R. , Wommack K. Eric 
Published: February 2009

ABSTRACT

Direct enumeration and genetic analyses indicate that aquatic sediments harbor abundant and diverse viral communities. Thus far, synecological analysis of estuarine sediment viral diversity over an annual cycle has not been reported. This oversight is due in large part to a lack of molecular genetic approaches for assessing viral diversity within a large collection of environmental samples. Here, randomly amplified polymorphic DNA PCR (RAPD-PCR) was used to examine viral genotypic diversity within Chesapeake Bay sediments. Using a single 10-mer oligonucleotide primer for all samples, RAPD-PCR analysis of sediment viral assemblages yielded unique banding patterns across spatial and temporal scales, with the occurrence of specific bands varying among the sample set. Cluster analysis of RAPD-PCR amplicon banding patterns indicated that sediment viral assemblages changed with season and to a lesser extent with geographic location. Sequence analysis of RAPD-PCR amplicons revealed that 76% of sediment viral sequences were not homologous to any sequence in the GenBank nonredundant protein database. Of the GenBank sequence homologs, the majority belonged to viruses within the
Podoviridae
(24%) and
Myoviridae
(22%) viral families, which agrees with the previously observed frequencies of these morphological families in Chesapeake Bay sediments. Furthermore, the majority of the sediment viral sequences homologous to GenBank nonredundant protein sequences were phages or prophages (57%). Hence, RAPD-PCR proved to be a reliable and useful approach for characterization of viral assemblages and the genetic diversity of viruses within aquatic sediments.
Variation in Bacterial ATP Level and Proton Motive Force Due to Adhesion to a Solid Surface
Authors: Hong Yongsuk , Brown Derick G. 
Published: February 2009

ABSTRACT

Bacterial adhesion to natural and man-made surfaces can be beneficial or detrimental, depending on the system at hand. Of vital importance is how the process of adhesion affects the bacterial metabolic activity. If activity is enhanced, this may help the cells colonize the surface, whereas if activity is reduced, it may inhibit colonization. Here, we report a study demonstrating that adhesion of both
Escherichia coli
and
Bacillus brevis
onto a glass surface resulted in enhanced metabolic activity, assessed through ATP measurements. Specifically, ATP levels were found to increase two to five times upon adhesion compared to ATP levels in corresponding planktonic cells. To explain this effect on ATP levels, we propose the hypothesis that bacteria can take advantage of a link between cellular bioenergetics (proton motive force and ATP formation) and the physiochemical charge regulation effect, which occurs as a surface containing ionizable functional groups (e.g., the bacterial cell surface) approaches another surface. As the bacterium approaches the surface, the charge regulation effect causes the charge and pH at the cell surface to vary as a function of separation distance. With negatively charged surfaces, this results in a decrease in pH at the cell surface, which enhances the proton motive force and ATP concentration. Calculations demonstrated that a change in pH across the cell membrane of only 0.2 to 0.5 units is sufficient to achieve the observed ATP increases. Similarly, the hypothesis indicates that positively charged surfaces will decrease metabolic activity, and results from studies of positively charged surfaces support this finding.
Spontaneous Quinolone Resistance in the Zoonotic Serovar of
Vibrio vulnificus
Authors: Roig Francisco J. , Llorens A. , Fouz B. , Amaro C. 
Published: February 2009

ABSTRACT

This work demonstrates that
Vibrio vulnificus
biotype 2, serovar E, an eel pathogen able to infect humans, can become resistant to quinolone by specific mutations in
gyrA
(substitution of isoleucine for serine at position 83) and to some fluoroquinolones by additional mutations in
parC
(substitution of lysine for serine at position 85). Thus, to avoid the selection of resistant strains that are potentially pathogenic for humans, antibiotics other than quinolones must be used to treat vibriosis on farms.