bluuebunny/crossref_metadata_2025 huggingface dataset:
Modulation of Yeast Alkaline Cation Tolerance by Ypi1 Requires Calcineurin
Authors: Marquina Maribel , González Asier , Barreto Lina , Gelis Samuel , Muñoz Iván , Ruiz Amparo , Álvarez Mari Carmen , Ramos José , Ariño Joaquín
Published: February 2012

Ypi1 was discovered as an essential protein able to act as a regulatory subunit of the Saccharomyces cerevisiae type 1 protein phosphatase Glc7 and play a key role in mitosis. We show here that partial depletion of Ypi1 causes lithium sensitivity and that high levels of this protein confer a lithium-tolerant phenotype to yeast cells. Remarkably, this phenotype was independent of the role of Ypi1 as a Glc7 regulatory subunit. Lithium tolerance in cells overexpressing Ypi1 was caused by a combination of increased efflux of lithium, mediated by augmented expression of the alkaline cation ATPase ENA1, and decreased lithium influx through the Trk1,2 high-affinity potassium transporters. Deletion of CNB1, encoding the regulatory subunit of the calcineurin phosphatase, blocked Ypi1-induced expression of ENA1, normalized Li+ fluxes, and abolished the Li+ hypertolerant phenotype of Ypi1-overexpressing cells. These results point to a complex role of Ypi1 on the regulation of cation homeostasis, largely mediated by the calcineurin phosphatase.
Wetting of Polyamide Film Surfaces with Electrospun Nanofibers
Authors: Stachewicz Urszula , Benett Chantal , Barber Asa H.
Published: February 2012

The wetting behavior of polyamide films was modified by depositing electrospun nanofibers manufactured from the same polyamide material. Glycerol contact angles on the film surfaces with low coverage of electrospun nanofibers were successfully predicted using a Cassie-Baxter relationship but could not be predicted for high electrospun nanofiber coverage.
Selective Aggregation of Hydrophilic Gangue Minerals in Froth Flotation
Authors: Liu Qi
Published: February 2012

In a highly dispersed flotation pulp, ultrafine hydrophilic minerals can entrain into froth products even though they may be perfectly hydrophilic. Therefore, effective depression of the hydrophilic minerals in froth flotation relies not only on rendering the minerals hydrophilic, but also on proper particle size control. In this paper, it will be shown that several depressants in mineral flotation systems indeed not only make the minerals hydrophilic but also cause selective coagulation or flocculation of the hydrophilic minerals. As a result, both the genuine flotation and the hydraulic entrainment of the hydrophilic minerals are reduced. The aforementioned depressants and mineral flotation systems include: zinc sulfate in the depression of sphalerite while copper sulfide and lead sulfide are floated; starch in the depression of iron oxides and phosphates while quartz is floated; polyethylene oxide in the depression of quartz while sulfide minerals such as chalcopyrite is floated.

Therefore, in fine and ultrafine particle flotation, the flotation depressants should be able to not only make the to-be-depressed minerals hydrophilic, but also make them selectively aggregate.
Production process of zeolite X using alum sludge issued from drinking water treatment plants
Authors: Espejel-Ayala F. , Ramírez Z. R. M.
Published: February 2012

The present work describes a patent applied for registration at the IMPI (Instituto Mexicano de la Propiedad Industrial) of a production process of zeolite X using as raw materials alum sludges issued from drinking water treatment plants. Sludge sample was collected in a water drinking plant located northern Mexico City. The sample was dried and then physicochemical and microbiological analyses were carried out (metal content, main oxides content, mineralogical analysis, helminth eggs content, fecal coliforms). In accordance with its characterization, two main steps of the zeolites production process were performed: 1) alkaline fusion of alum sludge-NaOH mixture for increasing the dissolved precursor’s content and 2) alkaline hydrothermal treatment. Spherical particles of zeolite X were identified by SEM and XRD respectively. The best synthesized zeolite showed a CEC=2.11 meq/g, value being similar to the data reported for clinoptilolite (the most commonly zeolite used for water treatment in the removal of heavy metals). Thus, the synthesized zeolite X in this work can be used for the same purpose.
Mathematical Simulation of the Copper Drossing in Lead Bath with Sulphur Injection
Authors: Gutiérrez Pérez Victor Hugo , Cruz Ramírez Alejandro , Vargas Ramírez Marissa , Gonzalez Nava Marlenne , Sánchez Martínez Angélica
Published: February 2012

Lead is an engineering material used mainly in the manufacturing of lead-acid batteries for the automotive industry. Lead recovery from exhausted batteries is carried out by the pyrometallurgical route by injecting sulfur the powder reagent through a lance into the lead bath. In this work a mathematical simulation was carried out on the copper drossing process with the software COMSOL 3.4. A kinetic study of the injection process of the lance-kettle system was carried out. The copper concentration profiles were obtained according with the injection rate of the particles. The best conditions for the copper drossing process were an injection rate of 3.31 m/s at 380°C. The modeling results were validated with experimental results obtaining good agreement.
ANALYSIS OF WASHABILITY OF SABINAS BASIN COAL: INFLUENCE OF ASH CONTENT AND FIXED CARBON ON CALORIFIC VALUE.
Authors: Martínez-Carrillo D. , Pecina-Treviño E.T. , Gómez-Borrego M.A. , Estrada-Ruiz R.H.
Published: February 2012

Coal deposits in Mexico were firstly recognized back in 1850, the main coal deposits in Mexico are located north of the Coahuila State. Coal samples from coal mines of Sabinas Basin were collected and analyzed for chemical composition, separation characteristic and calorific value (CV). The analytical data indicate that the coals usually have low or high ash content (Ash), 17 – 50 wt %, depending on the sample source. Comparison of the calorific value with both ahs content and fixed carbon, indicate that these two parameters are directly connected together: the higher the calorific value of coal, the lower the ash content and high fixed carbon content. Rejection of the ash using sink-flotation technique and their ratio whit the calorific value (CV/Ash) was evaluated in this study. Also, the ratio of Calorific value to fixed carbon (FC) was analyzed. Washability analyses for selected coal sample (+1 ½”, -1 ½” + ½”, -½” +¼“, - ¼“ + 1/16”, -1/16” +#100, size group) using heavy organic liquids with a density from 1.3 to 1.6 gr/cm3, were carried out. Calorific value-ash (%)-Fixed Carbon relationship was presented. The results indicate that the ratio CV/Ash vs. specific gravity has an exponential behavior, whereas the value of the ratio CV/FC was found to be 117.3.
Discrete Material Media Under Vertical Perturbation
Authors: Damas José , Zurigel Iker , Maza Diego
Published: February 2012

In this work we present new experimental results about the packing fraction of a granular monolayer excited by taps in the gravity direction. The role of large amplitude of tapping is discussed. Also, the relationship between packing fraction and the number of particles in the sample is analyzed.
Research on Preparation and Performance of Vandium Tailings-based Geopolymer
Authors: Chen Tie-jun , Zhang Yi-min , Jiao Xiang-ke , Zhao Jie
Published: February 2012

Vanadium-beard bone coal is one of important vanadium resources in China. to extract vanadium tailings from Stone coal is prduced after extracted vanadium from stone coal through the roasting, leaching and other processes. About 120-150 tons of tailings will be produced in extracting 1 ton of vanadium pentoxide. A lot of tailings that are willfully piled up have caused serious environmental pollution and wasting of resources; it is therefore necessary to realize its resource utilization. This study increases the activity of vanadium tailings by means of alkali fusion, and then uses different alkali activators to react with vanadium tailings so that geopolymer with high value added is produced. Sample of geopolymer is acquired from mixture containing vanadium tailings, alkali activators, water and a little sodium aluminate through compression-molding process under 20MPa pressure. After cured in room temperature for three days, the maximum compressive strength of the sample can reach 36.2MPa. XRD analysis indicates: quartz, the major crystal phase in vanadium tailings is decomposed and the activity of vanadium tailings is heightened. FTIR and SEM analyses show: structural change having important impact on the mechanical strength of geopolymer occurred during the process of vanadium tailings generating geopolymer.
Aerobic and anaerobic mineralization of Salvinia molesta and Myriophyllum aquaticum leachates from a tropical reservoir (Brazil)
Authors: Silva Renato Henriques da , Panhota Rafael Spadaccia , Bianchini Junior Irineu
Published: February 2012

AIM: This study aimed at describing and discussing the leachates mineralization (aerobic and anaerobic) of two species of aquatic macrophytes (Salvinia molesta and Myriophyllum aquaticum) from a tropical reservoir (22° 00' S and 47° 54' W); METHODS: The incubations were prepared with plant leachates and reservoir water sample and were maintained during 45 days in the dark (at 20 °C). The organic carbon and the oxygen consumption kinetics were evaluated; RESULTS: Irrespective of to the experimental condition, the leachates were mainly utilized for catabolic processes (i.e., respiration), mineralization was slightly faster in an aerobic environment (1.22 fold) and in this condition, the yield of refractory products was smaller (2.3%); the O/C stoichiometric ratios values (oxygen consumed per atom of carbon) from mineralization of the 2 types of leachates were similar (ca. 1.12); CONCLUSIONS: According to these results we conclude that the leachate from selected macrophytes is rapidly decomposed and subsidize primariy the microbial catabolism (aerobic or anaerobic); in addition, we propose that S. molesta contributes more to the input of dissolved organic matter within the reservoir.
Effect of salt stress on nutrient concentration, photosynthetic pigments, proline and foliar morphology of Salvinia auriculata Aubl.
Authors: Gomes Maria Angélica da Conceição , Suzuki Marina Satika , Cunha Maura da , Tullii Cristiane Ferrante
Published: February 2012

AIM: This study aimed to investigate the effects of NaCI and Na2So4 salts on Ca, CI, K, Mg N, P, S and Na content as well as on the content of photosynthetic pigments (chlorophyll-a, chlorophyll-b and carotenoids), proline content and on the foliar morphology of Salvinia auriculata Aubl. METHODS: The plants were collected in Jacu lagoon, located in the North of Rio de Janeiro State, and after a five-day-acclimation period, experiments were performed in the greenhouse with 0, 100, 200 mM concentrations of NaCI and Na2SO4 salts and the usual techniques for light and electron microscopy. RESULTS: After seven days of experiment, a decrease in the content of Ca2+, K+, Mg2+, P, N ions as well as in the content of photosynthetic pigments (chlorophyll-a,b and carotenoids) in Salvinia auriculata under saline treatments was observed. The proline content showed an upward tendency as compared to the control. Under transmission electron microscopy, it was observed that, on the foliar limb, there was a membrane system disorder, mainly of chloroplasts, with higher presence of starch grains of plant cells subjected to salinity. Under scanning electron microscope, the integrity of trichomes and foliar limb cells of Salvinia auriculata subjected to the control treatment as well as the changes caused by salinization on the surface of cells were observed. CONCLUSION: As for all the salinization effects evaluated, it was noticed that the increase in Na2SO4 salt concentration resulted in higher morphological and nutritional alterations in the floating aquatic macrophyte, Salvinia auriculata.
Spatial evaluation of water quality in an urban reservoir (Billings Complex, southeastern Brazil)
Authors: Wengrat Simone , Bicudo Denise de Campos
Published: February 2012

AIM: The study aimed at (a) contributing to a spatial evaluation of the Billings Complex water quality; (b) associating information on the geochemistry of the surface sediments; and (c) providing, based on previous studies, a temporal evaluation of the Complex's water quality since the Pinheiros River pumping restriction; METHODS: sampling was performed at 12 sites: 2 in the Central body (CB), 3 in the Taquacetuba branch (TQ), 3 in the Rio Pequeno branch (RP) and 4 in the Rio Grande Reservoir (RG). Water samples were taken along a vertical profile during the winter (August 2009) and summer (February 2010) and in the surface sediments (2 cm) during the winter. Physical and chemical characteristics of water and sediments were evaluated. Lamparelli's Trophic State Index (TSI) was calculated; RESULTS: limnological variability was mostly affected by the season. The spatial heterogeneity of the Complex was more pronounced during winter, with greater differences among its compartments. Nitrogen was higher in the winter, whereas in the summer there was a substantial phosphorus increase along with a nitrogen decrease. The most degraded compartments, associated with the highest nutrient levels, were CB and TQ. In contrast, the upstream region of the RP branch was considered a reference site (the least impacted) for the Complex; CONCLUSION: The Billings Complex ranged from mesotrophic (RP) or eutrophic (RG) to super-eutrophic (CC, TQ). High TSI variation also occurred within compartments and/or depending on the season, mainly associated with the human management of the Complex. The surface sediments underlined the differences observed between the extremes in the Billings Complex water quality, as well as providing additional information on other impacts that was not observed from the water analysis. A slight improvement in the water quality of the Central body and the Taquacetuba branch has been observed since 2009, possibly associated with the Pinheiros River flotation project.
Zooplankton body-size structure and biomass in tropical floodplain lakes: relationship with planktivorous fishes
Authors: Bonecker Claudia Costa , Azevedo Fábio de , Simões Nadson Ressyé
Published: February 2012

AIM: This study evaluated whether the size structure of the zooplankton community, as analyzed from density and biomass, would be influenced by bottom-up and/or top-down mechanisms in isolated lakes from the Upper Paraná River floodplain during dry and rainy periods. METHODS: zooplankton individuals were classified as: smaller-sized (<300 µm), intermediate-sized (301 to 600 µm) and larger-sized (greater than 601 µm). Fish abundance was indexed by the capture per unit effort (CPUE; number of individuals.100 m-2). Productivity was measured as chlorophyll-a. RESULTS: The size structure of the community did not show significant relationship with chlorophyll-a concentration (p > 0.05), but it was associated to the increase in fish density during the dry season. The percentage of individuals with intermediate sizes (301 to 600 µm), in both biomass and density, was positively related to the fish density (R2 = 0.78 for biomass, p < 0.001; R2 = 0.58 for density, p = 0.02), indicating an increase numerical and mass of this size class with fish density. The percentage of larger-sized individuals (>600 µm), in both biomass (R2 = 0.86, p < 0.001) and density (R2 = 0.69, p = 0.02) was negatively associated to the fish density, reflecting a decrease of this size class with the increase of fish in the environment. CONCLUSIONS: This can implicate a direct and negative effect of the predation on larger-sized individuals, as well as indirect and positive effect on the intermediate-sized individuals, but it occurred only on dry season. Thus, different mechanisms act on the size structure of the zooplankton community between dry and rainy season.
A new apparatus for modelling excavations
Authors: Lam Sze Yue , Elshafie Mohammed Z. E. B. , Haigh Stuart K. , Bolton Malcolm D.
Published: February 2012

Underground space is commonly exploited both to maximise the utility of costly land in urban development and to reduce the vertical load acting on the ground. Deep excavations are carried out to construct various types of underground infrastructure such as deep basements, subways and service tunnels. Although the soil response to excavation is known in principle, designers lack practical calculation methods for predicting both short- and long-term ground movements. As the understanding of how soil behaves around an excavation in both the short and long term is insufficient and usually empirical, the judgements used in design are also empirical and serious accidents are common. To gain a better understanding of the mechanisms involved in soil excavation, a new apparatus for the centrifuge model testing of deep excavations in soft clay has been developed. This apparatus simulates the field construction sequence of a multi-propped retaining wall during centrifuge flight. A comparison is given between the new technique and the previously used method of draining heavy fluid to simulate excavation in a centrifuge model. The new system has the benefit of giving the correct initial ground conditions before excavation and the proper earth pressure distribution on the retaining structures during excavation, whereas heavy fluid only gives an earth pressure coefficient of unity and is unable to capture any changes in the earth pressure coefficient of soil inside the zone of excavation, for example owing to wall movements. Settlements of the ground surface, changes in pore water pressure, variations in earth pressure, prop forces and bending moments in the retaining wall are all monitored during excavation. Furthermore, digital images taken of a cross-section during the test are analysed using particle image velocimetry to illustrate ground deformation and soil–structure interaction mechanisms. The significance of these observations is discussed.
Focus on African freshwaters: hotspots of dragonfly diversity and conservation concern
Authors: Clausnitzer Viola , Dijkstra Klaas-Douwe B , Koch Robert , Boudot Jean-Pierre , Darwall William RT , Kipping Jens , Samraoui Boudjéma , Samways Michael J , Simaika John P , Suhling Frank
Published: February 2012

This is the first continent‐wide overview of insect diversity and status sufficiently fine‐scaled to be used in conservation planning. We analyze patterns of richness and the conservation status of African dragonflies and damselflies (Insecta: Odonata), commonly referred to as dragonflies, to determine threats to species and freshwater habitats, location of diversity hotspots, necessary conservation actions, and research gaps. Major centers of dragonfly diversity in Africa are tropical forest areas that include highlands. Most threatened species – as classified by the International Union for Conservation of Nature global Red List – are concentrated in highlands from Kenya to South Africa (together with the Cape Floristic Region), western Africa (including mountains on the Cameroon–Nigeria border), and Ethiopia. Currently available knowledge can be applied throughout Africa's freshwater systems to help minimize or mitigate the impact of future development actions, allowing dragonflies to act as “guardians of the watershed”. The private sector can be advised to safeguard sensitive habitats and species when selecting sites for development. Key sites and species for monitoring can be identified by checking the distribution of threatened species at www.iucnredlist.org.
Searching for Alouatta palliata in northern Colombia: considerations for the species detection, monitoring and conservation in the dry forests of Bolívar, Colombia
Authors: Dechner Andrea
Published: February 2012

The conservation status of A. palliata, commonly referred to as black mantled howler monkey, is vulnerable in Colombia because of its decline in population. The distributional limit in the northeast of the country is not well defined and the dry forests of the north of the country are being destroyed at alarming rates. In the municipality of El Guamo (Bolívar) less than 20% of the landscape is composed of forests. The two largest remnants of forests in the municipality have extensions of 3,544.7 and 879.6 ha each. From interviews with the community, I concluded that habitat loss is the main threat to primate populations. 37.6 % of the community of inhabitants said they had seen the monkey in the municipality of Guamo, however, I found no A. palliata during a short transect sampling. Individuals of the species Alouatta seniculus and Saguinus oedipus were detected during these walks. Conservation actions such as reforestation, establishment of agroforestry systems and corridors designed to improve the habitat of A. palliata should encourage the participation of the human communities.
Densidade e tamanho populacional de primatas em uma área de terra firme na Amazônia Central
Authors: Rodrigues Lilian Figueiredo , Vidal Marcelo Derzi
Published: February 2012

O Brasil apresenta 1/3 das florestas tropicais remanescentes do mundo e é reconhecidamente um dos mais importantes repositórios da diversidade biológica mundial. Quanto à riqueza de espécies de primatas, ocorrem em seu território 133 espécies e subespécies, sendo que 80 ocorrem em território amazônico e 11 estão ameaçadas de extinção. Apesar dos números expressivos, boa parte das espécies, principalmente as que ocorrem na região amazônica, apresenta carência de informações ecológicas e populacionais. Diante disto, os objetivos deste estudo foram (1) registrar as espécies de primatas, (2) estimar suas densidades e (3) caracterizar suas distribuições na Reserva Florestal Adolpho Ducke, uma área de floresta primária de 10.000 hectares situada na região de crescimento urbano norte da cidade de Manaus-AM. Os dados foram coletados por meio do método de transecção linear, cobrindo todo o sistema de trilhas da reserva. Foram percorridos 720 km e registrados 58 avistamentos de Saguinus bicolor, 29 de Cebus apella, 20 de Alouatta seniculus, 13 de Pithecia pithecia e 10 de Chiropotes sagulatus, distribuídos em todos os tipos de ambientes (platô, vertente e baixio). A maior densidade registrada foi de S. bicolor (1.00 Gr/Km2), seguida por C. apella (0.67), A. seniculus (0.66), P. pithecia (0.64) e C. sagulatus (0.30). Assim, a estimativa de grupos presentes na área total da reserva, desconsiderando-se a possível presença de lacunas, as variações naturais do habitat ou a disponibilidade dos recursos, é de 100 grupos de S. bicolor, 67 de C. apella, 66 de A. seniculus, 64 de P. pithecia e 30 de C. sagulatus. Esses resultados demonstram a importância da Reserva Florestal Adolpho Ducke na manutenção da biodiversidade e impõem a necessidade de políticas conservacionistas para sua área.
Southern extension of the geographical range of the pygmy marmoset Cebuella pygmaea niveiventris (Lönnberg, 1940) in the southwestern Amazon basin, state of Rondônia, Brazil
Authors: Messias Mariluce Rezende , Coragem Juliano Tupan , Gomes Ivonete Santa Rosa , Oliveira Marcela Alvares , Bonavigo Paulo Henrique , Nienow Samuel Santos , Souza Eduardo Santos
Published: February 2012

No abstract
Acute Effects of Very-Low-Protein Diet on FGF23 Levels
Authors: Di Iorio Biagio , Di Micco Lucia , Torraca Serena , Sirico Maria Luisa , Russo Luigi , Pota Andrea , Mirenghi Francesco , Russo Domenico
Published: February 2012

Background and objectives

High levels of fibroblast growth factor 23 are associated with mortality, CKD progression, and calcification in CKD patients. The aim of this pilot study is to assess whether a very-low-protein diet (0.3 g/kg per day) with a consequent low intake of phosphorus would reduce fibroblast growth factor 23 compared with a low-protein diet (0.6 g/kg per day) in CKD patients not yet on dialysis.

Design, setting, participants, & measurements

A prospective, randomized, controlled crossover study was performed in which 32 patients were randomized into two groups. Group A (16 patients) received a very-low-protein diet (0.3 g/kg body wt per day) supplemented with ketoanalogues during the first week and a low-protein diet during the second week, and group B (16 patients) received a low-protein diet during the first week and a very-low-protein diet during the second week. Fibroblast growth factor 23, seric, and urinary phosphate levels were measured at baseline and the end of each study period.

Results

After only 1 week of the very-low-protein diet, reductions in fibroblast growth factor 23 levels (33.5%), serum phosphate (12%), and urinary phosphate (34%) with the very-low-protein diet compared with the low-protein diet were observed. Serum and urinary phosphate levels and protein intake were significant determinants of fibroblast growth factor 23 (95% confidence interval=1.04–1.19, 1.12–1.37, and 1.51–2.23, respectively).

Conclusions

A very-low-protein diet supplemented with ketoanalogues reduced fibroblast growth factor 23 levels in CKD patients not yet on dialysis.
Fluoroscopic Manipulation of Peritoneal Dialysis Catheters
Authors: Miller Matthew , McCormick Brendan , Lavoie Susan , Biyani Mohan , Zimmerman Deborah
Published: February 2012

Background and objectives

Mechanical failure of the peritoneal dialysis (PD) catheter is an important cause of technique failure. Fluoroscopic guidewire manipulation may be undertaken in an attempt to correct the failure. The purpose of this study was to determine the efficacy of fluoroscopic manipulation of previously embedded PD catheters, the factors associated with successful manipulation, and the complication rate associated with manipulation.

Design, setting, participants, & measurements

A single-center, retrospective review of 70 consecutive PD patients undergoing fluoroscopic manipulation for mechanical failure of their PD catheter from June 2006 to February 2011 was undertaken. Logistic regression models were developed to determine the variables associated with successful manipulation.

Results

Of the 70 manipulations, 44 were successful (62.9%). In univariate analysis, catheters located in the pelvis compared with those in the upper abdomen (73.5% versus 42.9%, P=0.01) and catheters that were previously functional compared with those that failed at exteriorization (75.0% versus 46.7%, P=0.04) were more likely to be successfully manipulated. Time embedded, previous hemodialysis, and number of intra-abdominal surgeries were not correlated with likelihood of successful manipulation. In multivariate analysis, catheters located in the pelvis (P=0.01) and those with secondary failure (P=0.01) were more likely to successfully manipulated. Two of the patients developed peritonitis (2.9%), neither requiring cessation of PD.

Conclusions

Fluoroscopic manipulation is an effective and safe therapy for failed PD catheters that are unresponsive to conservative treatment. Properly positioned catheters and those that were previously functional are more likely to be successfully manipulated.
Optimization of cooling tower performance analysis using Taguchi method
Authors: Ramkumar Ramakrishnan , Ragupathy Arumugam
Published: February 2012

This study discuss the application of Taguchi method in assessing maximum
cooling tower effectiveness for the counter flow cooling tower using expanded
wire mesh packing. The experiments were planned based on Taguchi?s L27
orthogonal array .The trail was performed under different inlet conditions of
flow rate of water, air and water temperature. Signal-to-noise ratio (S/N)
analysis, analysis of variance (ANOVA) and regression were carried out in
order to determine the effects of process parameters on cooling tower
effectiveness and to identity optimal factor settings. Finally confirmation
tests verified this reliability of Taguchi method for optimization of counter
flow cooling tower performance with sufficient accuracy.
Microleakage of IPS Empress 2 Inlay Restorations Luted With Self-adhesive Resin Cements
Authors: Cal E , Celik EU , Turkun M
Published: February 2012

Objective

To assess the microleakage of three self-adhesive and one etch-and-rinse resin cements when luting IPS Empress 2 (Ivoclar Vivadent, Liechtenstein) all-ceramic inlay restorations to the prepared cavities in extracted human molars.

Methods

The cylindrical Class V cavities were prepared on the buccal surfaces of 40 extracted human third molars using diamond burs. The IPS Empress 2 ceramic inlays were placed with Multilink Sprint (Ivoclar Vivadent), RelyX Unicem (3M ESPE, USA), G-Cem (GC, Japan), or Variolink II (Ivoclar Vivadent) as the control group. After storage in distilled water at 37°C for 24 hours, samples were subjected to 1000 thermal cycles between baths of 5°C and 55°C, with a dwell time of 30 seconds. The microleakage scores were examined on the occlusal and gingival margins at 30× magnification after each sample was stained with 0.5% basic fuchsin and sectioned into three parts using a thin diamond blade (Isomet, Buehler, USA) (n=40). The extent of microleakage on both occlusal and gingival margins of the restorations was scored and recorded. The microleakage data were analyzed using Kruskall-Wallis and Mann-Whitney U-tests.

Results

Statistically significant differences were observed between the groups in both margins according to the Kruskall-Wallis and Mann-Whitney U-tests (p<0.05). Microleakage scores on the occlusal margins were Variolink II < RelyX Unicem < G-Cem = Multilink Sprint. Microleakage scores on the gingival margins are Variolink II = RelyX Unicem < G-Cem < Multilink Sprint.

Conclusion

Self-adhesive resin cements displayed higher microleakage scores on the occlusal margins, whereas on the gingival margins RelyX Unicem showed comparable microleakage results with the control samples.
Shear Bond Strength of Composite to Deep Dentin After Treatment With Two Different Collagen Cross-linking Agents at Varying Time Intervals
Authors: Srinivasulu S , Vidhya S , Sujatha M , Mahalaxmi S
Published: February 2012

Objective

This in vitro study evaluated the shear bond strength of composite resin to deep dentin using a total etch adhesive after treatment with two collagen cross-linking agents at varying time intervals.

Materials and Methods

Thirty freshly extracted human maxillary central incisors were sectioned longitudinally into equal mesial and distal halves (n=60). The proximal deep dentin was exposed, maintaining a remaining dentin thickness (RDT) of approximately 1 mm. The specimens were randomly divided into three groups based on the surface treatment of dentin prior to bonding as follows: group I (n=12, control): no prior dentin surface treatment; group II (n=24): dentin surface pretreated with 10% sodium ascorbate; and group III (n=24): dentin surface pretreated with 6.5% proanthocyanidin. Groups II and III were further subdivided into two subgroups of 12 specimens each, based on the pretreatment time of five minutes (subgroup A) and 10 minutes (subgroup B). Shear bond strength of the specimens was tested with a universal testing machine, and the data were statistically analyzed.

Results

Significantly higher shear bond strength to deep dentin was observed in teeth treated with 10% sodium ascorbate (group II) and 6.5% proanthocyanidin (group III) compared to the control group (group I). Among the collagen cross-linkers used, specimens treated with proanthocyanidin showed significantly higher shear bond strength values than those treated with sodium ascorbate. No significant difference was observed between the five-minute and 10-minute pretreatment times in groups II and III.

Conclusion

It can be concluded that dentin surface pretreatment with both 10% sodium ascorbate and 6.5% proanthocyanidin resulted in significant improvement in bond strength of resin composite to deep dentin.
Natural infections with Cryptosporidium in the endangered spotted souslik (Spermophilus suslicus)
Authors: Kloch Agnieszka , Bajer Anna
Published: February 2012

Cryptosporidium is an intestinal protozoan parasite prevalent in a wide range of mammals. Although it has been recorded in many hosts, its impact on endangered species is poorly understood. Here we present a preliminary study of four populations of the highly threatened spotted souslik (Spermophilus suslicus), living in the westernmost part of the species range. The populations inhabit fragmented habitats and suffer from loss of genetic variation. An IFA test revealed that 35.9% of sampled animals (41/114) was infected with Cryptosporidium and none with Giardia. The prevalence and infection intensity differed among the populations. In areas grazed by cattle it was about 3 folds higher, which suggests a possible transmission route. To the authors best knowledge the present study is the first report of Cryptosporidium infections in S. suslicus.
Fasciola hepatica miracidia: Lectin binding and stimulation of in vitro miracidium-to-sporocyst transformation
Authors: Georgieva Katya , Georgieva Simona , Mizinska Yana , Stoitsova Stoyanka
Published: February 2012

The lectin binding properties of Fasciola hepatica miracidia were studied by a panel of fluorescein- and gold-conjugated lectins (ConA, LCA, WGA, LEA, SBA, HPA and UEA-I). The presence of mannose and/or glucose residues was demonstrated with ConA and LCA as weak diffuse fluorescence of the miracidial surface, which was more intense at the anterior part of the larva. The N-acetylglucosamine-binding lectins WGA and LEA reacted intensely with the whole miracidial surface. No labelling with N-acetylgalactosamine and/or galactose-specific (SBA and HPA) and fucose-specific UEA-I lectins was observed. The possibility that the specific recognition of the miracidial surface carbohydrates by lectins may initiate the process of transformation of the miracidia into sporocysts was examined in vitro in physiological saline for Galba truncatula. Incubation in the presence of ConA and WGA resulted in facilitation of the transformation process. Facilitation was absent in the presence of inhibitor sugars. Incubation in the presence of SBA or UEA-I had no effect. The results suggested a possible impact of carbohydrate-lectin interactions in transformation of miracidia of F. hepatica to sporocysts in vivo.
Spermiogenesis and ultrastructure of the spermatozoon of Wardula capitellata (Digenea, Mesometridae), an intestinal parasite of the sparid teleost Sarpa salpa in Senegal
Authors: Bakhoum Abdoulaye , Ndiaye Papa , Sène Aminata , Bâ Cheikh , Miquel Jordi
Published: February 2012

The spermiogenesis process in Wardula capitellata begins with the formation of a differentiation zone containing two centrioles associated with striated rootlets and an intercentriolar body. Each centriole develops into a free flagellum orthogonal to a median cytoplasmic process. Later these flagella rotate and become parallel to the median cytoplasmic process, which already exhibits two electron-dense areas and spinelike bodies before its proximodistal fusion with the flagella. The final stage of the spermiogenesis is characterized by the constriction of the ring of arched membranes, giving rise to the young spermatozoon, which detaches from the residual cytoplasm. The mature spermatozoon of W. capitellata presents most of the classical characters reported in digenean spermatozoa such as two axonemes of different lengths of the 9 + “1” trepaxonematan pattern, nucleus, mitochondrion, two bundles of parallel cortical microtubules and granules of glycogen. However, some peculiarities such as two lateral expansions accompanied by external ornamentation of the plasma membrane and spinelike bodies characterize the mature sperm. Moreover, a new spermatological character is described for the first time, the so-called cytoplasmic ornamented buttons.
Demodex mite infestation in patients with and without rheumatoid arthritis
Authors: Garbacewicz Aleksandra , Jaworski Janusz , Grytner-Zięcina Barbara
Published: February 2012

In the present study we compared the prevalence of Demodex mites in patients with rheumatoid arthritis and in one control group involving individuals of similar mean age. From each person we epilated 3–4 lashes from each eyelid and examined them under a microscope to find Demodex mites. In total 147 patients were examined. The prevalence of Demodex mites was 33% in rheumatoid arthritis (RA) patients and 31% in the control group. Our results demonstrated that the prevalence of Demodex mites was similar in RA patients as compared to the control group.
Is the community of fish gill parasites structured in a Neotropical floodplain?
Authors: Bellay Sybelle , Takemoto Ricardo , Oliveira Edson
Published: February 2012

Sixty-one specimens of the piranha Serrasalmus marginatus Valenciennes, 1837 were analyzed, aiming at assessing the community structure of their gill parasites. The samples were collected in lagoons of the Paraná, Ivinheima and Baia Subsystems within the Upper Paraná River Floodplain (Brazil). Host size and sex had little or no influence on the abundance and prevalence of parasites. The organization of the gill parasite infracommunities of S. marginatus was significantly non-random according to null models and ordination analyses. In general, parasite infrapopulations were not affected by interspecific associations or host characteristics (e.g. size, sex), what highlights the importance of local habitat characteristics to community organization of gill parasites of S. marginatus in the Upper Paraná River Floodplain.
Rhabdochona (Rhabdochona) keralaensis sp. nov. (Rhabdochonidae) and some other nematodes in the Indian mottled eel Anguilla bengalensis bengalensis from India
Authors: Moravec František , Sheeba Sarasamma , Kumar Appukuttannair
Published: February 2012

A new species of parasitic nematode, Rhabdochona (Rhabdochona) keralaensis sp. nov., is described based on specimens recovered from the intestine of Anguilla bengalensis bengalensis (Gray) collected from the freshwater bodies of Kerala State, southern India. It is characterized mainly by the presence of ten anterior prostomal teeth, absence of basal teeth, simple deirids, length of spicules, number and arrangement of preanal papillae and non-filamented eggs. Two species of camallanid nematodes, adults of Camallanus cotti Fujita, 1927 and a single Procamallanus (Spirocamallanus) sp. fourth-stage larva, were also recorded from A. bengalensis. Camallanus cotti, a pathogenic parasite of many species of wild and aquarium-reared fishes in many countries of South and East Asia, Europe, South and North America, West Indies and Australia, is reported for the first time from a representative of the fish family Anguillidae. Descriptions of R. (R.) keralaensis and Indian specimens of C. cotti, based on light and scanning electron microscopical examinations, are provided. Camallanus oxygasterae Gupta et Bakshi, 1983 is considered a junior synonym of C. cotti.
Utrastructural observations on Goussia metchnikovi (Laveran, 1897) in the spleen of gudgeon, Gobio gobio L.
Authors: Ball Stanley , Daszak Peter , Davies Angela
Published: February 2012

The ultrastructure of gamonts and sporulated oocysts of Goussia metchnikovi in the spleen of gudgeon, Gobio gobio from the river Lee, England is described. In developing microgamonts, small amylopectin granules were grouped centrally and nuclei were often arranged peripherally, close to the surface membrane. Nuclear chromatin condensed into peripheral dense portions that became the nuclei of flagellated microgametes, released to the parasitophorous vacuole. The cytoplasm of macrogametes had larger, scattered amylopectin granules, lipid globules and small electron-dense bodies, but no obvious wall forming bodies; peripheral vesicular structures with the appearance of mitochondria were also present and the parasitophorous vacuole contained flocculent material, but was otherwise free of structures. Sporulated oocysts contained four sporocysts and oocyst walls appeared to consist of a single membrane. Sporocyst walls showed a dehiscence suture, characteristic of the genus Goussia, which had filamentous extensions in places. The sporocyst wall comprised a dense inner layer and a thin outer layer with a fuzzy coat, separated by an electron lucent layer. Groups of oocysts were encapsulated by fibrous layers and inflammatory cells, and many sporocysts and their contained sporozoites showed evidence of elimination by the host.
First record of an arthropod from the Passaic Formation (Late Triassic), near Milford, New Jersey
Authors: Metz Robert
Published: February 2012

Mudstones of the Triassic Passaic Formation, near Milford, New Jersey, have yielded the first evidence of an arthropod impression in that formation. Associated trace fossils include Helminthoidichnites, Lockeia, Scoyenia, Spongeliomorpha, and the reptile footprint Rhynchosauroides, representing the Scoyenia ichnofacies. Associated sedimentary structures include desiccation cracks and raindrop impressions. The Passaic sediments were deposited under shallow water lacustrine shoreline conditions subject to periodic subaerial exposure.
Comparative Analysis of Alternate Econometric Structures for Trip Generation Models
Authors: Lim Kwang-Kyun , Srinivasan Sivaramakrishnan
Published: February 2012

Traditionally trip generation models have been estimated with linear-regression structures even though this methodology does not recognize the nonnegativity and integer nature of the trips. Although the theoretical superiority of count-data models as an alternative approach is well recognized, the empirical benefits of such models have not been well established. In that context, the intent of this study is to undertake a comparative analysis of four different econometric structures for trip generation models. The structures are compared across three different trip purposes with significantly different distribution patterns. The models are estimated by using 2001 U.S. National Household Travel Survey data and are applied to samples from the 2009 National Household Travel Survey data. Predictive validations indicate that the ordered probit models are able to replicate the trip generation patterns better than linear-regression, log-linear, and negative-binomial models for all three trip purposes. The negative-binomial model performs reasonably well in the case of the non-home-based trips, which have a monotonically decreasing distribution pattern. The negative-binomial and the log-linear models have comparable mean errors for disaggregate predictions. Overall, this study recommends the use of ordered probit models as a substitute for the traditional linear-regression models.
Integrated Equilibrium Travel Demand Model with Nested Logit Structure
Authors: Zhang Ti , Xie Chi , Waller S. Travis
Published: February 2012

This paper presents an integrated travel demand modeling problem that accommodates the traditional travel demand modeling process in a nested logit structure for hierarchical travel choices, including travel, destination, mode, and route choices. The problem is characterized by a closed-form fixed-point model, which properly describes the asymmetric flow–cost effects of different transportation modes in an interactive traffic environment. The method of successive averages is adopted for problem solutions. The proposed model and solution method is further implemented to study travel demand distribution variations caused by model and data uncertainties. Specifically, the Monte Carlo simulation technique is adopted here to simulate and derive solution variations. Through a numerical example, the uncertainty analysis exhibits diverse demand variation patterns and degrees across different demand aggregation levels under different uncertainty sources.
Estimating Through-Trip Travel without External Surveys
Authors: Talbot Eric S. , Burris Mark W. , Farnsworth Steve
Published: February 2012

Because through trips can be a significant portion of travel in a study area, estimating them is an important part of travel demand modeling. In the past through trips were often estimated by using external surveys. External surveys were recently suspended in Texas, so Texas transportation planners need a way to estimate through trips without using external surveys. Previous research has focused on study areas with populations of less than 200,000, but many Texas study areas have populations of more than 200,000. This research developed a set of two logit models to estimate through trips for a wide range of study area sizes. The first model estimates the portion of all trips at an external station that are through trips. The second model estimates the external stations at which the trips originated. The models produce separate results for commercial and noncommercial vehicles, and these results can be used to develop through-trip tables. For predictor variables, the models use results from a simple gravity model, the average daily traffic at each external station as a proportion of the total average daily traffic at all external stations, the number of turns on the routes between external station pairs, and whether the route passes through the study area and does not pass through any other external stations. Evaluations of the models’ performance showed that the predictions fit the observations reasonably well, indicating that the models can be useful for practical applications.
Planning-Constrained Destination Choice in Activity-Based Model
Authors: Auld Joshua , Mohammadian Abolfazl (Kouros)
Published: February 2012

This paper describes a destination choice model estimated for Chicago, Illinois, with the use of a recent survey and a previously developed model of activity planning decision timing. The travel survey data are used to estimate a standard multinomial destination choice model and a model in which the choice set is constrained by what has already been planned in the schedule. The performance of each model is evaluated, as is the effect that using the planning-constrained model in place of the standard model has on the accuracy of the results. Using a model in which the destination choices are conditioned on what has been previously planned improves the accuracy. This improvement is true for correctly predicted location choices, especially for overall trip length distributions in which more realistic distributions are observed when decisions are constrained.
Phenotypic Characteristics Of Indigenous Sheep Of Bangladesh
Authors: Pervage S , Ershaduzzaman M , Talukder MAI , Hasan MN , Khandoker MAMY
Published: February 2012

This experiment was undertaken to know the phenotypic characteristics of native sheep. The study was conducted to investigate morphometric characters of sheep in three different field sites (Naogaon, Noakhali and Tangail) and Bangladesh Livestock Research Institute (BLRI) nucleus flock through close observation, measuring and record keeping. Characteristics of body weight, body length, heart girth, wither height, fore leg length, hind leg length, head length, ear length, ear width, horn length etc were collected from mature sheep. The results indicate that the average litter size, birth weight, weaning weight and body weight gain were comparatively higher in sheep of BLRI nucleus flock than those of other three regions. The average numbers of service/conception, post partum heat period (days), age at first heat (days), age at first lambing (days), lambing interval (days) were 1.30, 34.13, 266.50, 432.72, 192.17 respectively in BLRI nucleus flock which were comparatively better than the other three regions. The average litter size, birth weight (kg), weaning weight (kg) and body weight gain (g) in nucleus flock were 1.80, 1.19, 6.74 and 60.70 consequently. The overall performance of the sheep of BLRI nucleus flock were comparatively better than the others which may be due to the result of selective breeding, improve feeding, housing, health management etc. DOI: http://dx.doi.org/10.3329/bjas.v38i1-2.9906 BJAS 2009; 38(1-2): 1-6