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Sample records for fissure type vents

  1. Tectono-volcanic control of fissure type vents for the 28 Ma Panalillo ignimbrite in the Villa de Reyes Graben, San Luis Potosí, México.

    NASA Astrophysics Data System (ADS)

    Tristán-González, Margarito; Labarthe-Hernández, Guillermo; Aguirre-Díaz, Gerardo J.; Aguillón-Robles, Alfredo

    2008-10-01

    The volcano-tectonic events at the Villa de Reyes Graben (VRG), in the southern Sierra Madre Occidental, Mexico, include 1) a regional NNE fault system developed before 32 Ma, 2) this pre-32 Ma faulting controlled the emplacement of 31.5 Ma dacitic domes, 3) NE faulting at 28 Ma that displaced the 31.5 Ma dacitic domes and formed the VRG, as well as the oblique grabens of Bledos and Enramadas oriented NW, 4) emplacement of Panalillo ignimbrite at 28 Ma filling the VRG and erupting from fissures related to the oblique grabens, and eruption of Placa basalt apparently also from fault-controlled vents.

  2. Hawaiian fissure fountains: Quantifying vent and shallow conduit geometry, episode 1 of the 1969-1974 Mauna Ulu eruption: Chapter 17

    USGS Publications Warehouse

    Parcheta, Carolyn; Fagents, Sarah; Swanson, Donald A.; Houghton, Bruce; Ericksen, Todd; Carey, Rebecca; Cayol, Valérie; Poland, Michael P.; Weis, Dominique

    2015-01-01

    Geometries of shallow magmatic pathways feeding volcanic eruptions are poorly constrained, yet many key interpretations about eruption dynamics depend on knowledge of these geometries. Direct quantification is difficult because vents typically become blocked with lava at the end of eruptions. Indirect geophysical techniques have shed light on some volcanic conduit geometries, but the scales are too coarse to resolve narrow fissures (widths typically 1 m). Kīlauea's Mauna Ulu eruption, which started with <50 m high Hawaiian fountains along a 4.5 km fissure on 24 May 1969, provides a unique opportunity to measure the detailed geometry of a shallow magmatic pathway, as the western vents remain unobstructed to depths >30 m. Direct measurements at the ground surface were augmented by tripod-mounted lidar measurements to quantify the shallow conduit geometry for three vents at a resolution <4 cm. We define the form of the fissure in terms of aspect ratio, flaring ratio, irregularity, sinuosity, and segmentation and discuss the factors influencing these parameters. In the past, simplified first-order fissure geometries have been used in computational modeling. Our data can provide more accurate conduit shapes for better understanding of shallow fissure fluid dynamics and how it controls eruptive behavior, especially if incorporated into computer models.

  3. Video monitoring reveals pulsating vents and propagation path of fissure eruption during the March 2011 Pu'u 'Ō'ō eruption, Kilauea volcano

    NASA Astrophysics Data System (ADS)

    Witt, Tanja; Walter, Thomas R.

    2017-01-01

    Lava fountains are a common eruptive feature of basaltic volcanoes. Many lava fountains result from fissure eruptions and are associated with the alignment of active vents and rising gas bubbles in the conduit. Visual reports suggest that lava fountain pulses may occur in chorus at adjacent vents. The mechanisms behind such a chorus of lava fountains and the underlying processes are, however, not fully understood. The March 2011 eruption at Pu'u 'Ō'ō (Kilauea volcano) was an exceptional fissure eruption that was well monitored and could be closely approached by field geologists. The fissure eruption occurred along groups of individual vents aligned above the feeding dyke. We investigate video data acquired during the early stages of the eruption to measure the height, width and velocity of the ejecta leaving eight vents. Using a Sobel edge-detection algorithm, the activity level of the lava fountains at the vents was determined, revealing a similarity in the eruption height and frequency. Based on this lava fountain time series, we estimate the direction and degree of correlation between the different vents. We find that the height and velocity of the eruptions display a small but systematic shift in time along the vents, indicating a lateral migration of lava fountaining at a rate of 11 m/s from W to E. This finding is in agreement with a propagation model of a pressure wave originating at the Kilauea volcano and propagating through the dyke at 10 m/s from W to E. Based on this approach from videos only 30 s long, we are able to obtain indirect constraints on the physical dyke parameters, with important implications for lateral magma flow processes at depth. This work shows that the recording and analysis of video data provide important constraints on the mechanisms of lava fountain pulses. Even though the video sequence is short, it allows for the confirmation of the magma propagation direction and a first-order estimation of the dyke dimensions.

  4. Relationships between lava types, seafloor morphology, and the occurrence of hydrothermal venting in the ASHES vent field of Axial Volcano. [Axial Seamount Hydrothermal Emission Study

    SciTech Connect

    Hammond, S.R. )

    1990-08-10

    Deep-towed and submersible photographic surveys within the caldera of Axial Volcano have been integrated with high-resolution bathmetry to produce a geological map of the most active vent field in the caldera. Locations for over 2,000 photographs in and near the vent field were determined using a seafloor transponder network. Then each photograph was described utilizing a classification system which provides detailed information concerning lava type, hydrothermal activity, sediment cover, geological structure, and biology. Resulting data were entered into a digital data base, and computer-generated maps were created that portray spatial relationships between selected geological variables. In general, the entire ASHES field is characterized by pervasive low-temperature venting. The most vigorous venting is concentrated in an approximately 80 m {times} 80 m area where there are several high-temperature vents including some which are producing high-temperature vapor-phase fluids derived from a boiling hydrothermal system. Lava types within the ASHES vent field are grouped into three distinct morphologies: (1) smooth (flat-surfaced, ropy, and whorled) sheet flows, (2) lobate flows, and (3) jumbled-sheet flows. The most intense hydrothermal venting is concentrated in the smooth sheet flows and the lobate flows. The location of the ASHES field is mainly attributable to faulting which defines the southwest caldera wall, but the concentration of intense venting appears to be related also to the spatial distribution of lava types in the vent field and their contrasting permeabilities. Other structural trends of faults and fissures within the field also influence the location of individual events.

  5. Phimosis with Preputial Fissures as a Predictor of Undiagnosed Type 2 Diabetes in Adults.

    PubMed

    Huang, Yun-Ching; Huang, Yao-Kuang; Chen, Chih-Shou; Shindel, Alan W; Wu, Ching-Fang; Lin, Jian-Hui; Chiu, Kuo-Hsiung; Yang, Tzu-Hsin; Shi, Chung-Sheng

    2016-03-01

    Diabetes is usually asymptomatic in its early stage. Early diagnosis may improve outcomes by enabling initiation of treatment before end organ damage has progressed. The aim of this study was to determine whether the clinical sign of phimosis with preputial fissures is predictive of type 2 diabetes in patients not previously diagnosed with diabetes. Twenty-eight patients with acquired phimosis and preputial fissures were collected prospectively. Twenty-eight controls with acquired phimosis without preputial fissures were selected. Statistically significant differences were found in body mass index, random plasma glucose, glucosuria and glycosylated haemoglobin levels, but not in age, family history of diabetes, hypertension and classical hyperglycaemic symptoms. Diabetes was confirmed in all 28 patients in the preputial fissures group, but only 2 (7.1%) patients in the non-preputial fissures group (p < 0.0001). In conclusion, phimosis with preputial fissures may be a specific sign of undiagnosed diabetes mellitus.

  6. Time-series analysis of fissure-fed multi-vent activity: a snapshot from the July 2014 eruption of Etna volcano (Italy)

    NASA Astrophysics Data System (ADS)

    Spina, L.; Taddeucci, J.; Cannata, A.; Sciotto, M.; Del Bello, E.; Scarlato, P.; Kueppers, U.; Andronico, D.; Privitera, E.; Ricci, T.; Pena-Fernandez, J.; Sesterhenn, J.; Dingwell, D. B.

    2017-07-01

    On 5 July 2014, an eruptive fissure opened on the eastern flank of Etna volcano (Italy) at 3.000 m a.s.l. Strombolian activity and lava effusion occurred simultaneously at two neighbouring vents. In the following weeks, eruptive activity led to the build-up of two cones, tens of meters high, here named Crater N and Crater S. To characterize the short-term (days) dynamics of this multi-vent system, we performed a multi-parametric investigation by means of a dense instrumental network. The experimental setup, deployed on July 15-16th at ca. 300 m from the eruption site, comprised two broadband seismometers and three microphones as well as high speed video and thermal cameras. Thermal analyses enabled us to characterize the style of eruptive activity at each vent. In particular, explosive activity at Crater N featured higher thermal amplitudes and a lower explosion frequency than at Crater S. Several episodes of switching between puffing and Strombolian activity were noted at Crater S through both visual observation and thermal data; oppositely, Crater N exhibited a quasi-periodic activity. The quantification of the eruptive style of each vent enabled us to infer the geometry of the eruptive system: a branched conduit, prone to rapid changes of gas flux accommodated at the most inclined conduit (i.e. Crater S). Accordingly, we were able to correctly interpret acoustic data and thereby extend the characterization of this two-vent system.

  7. Health-related quality of life in patients with anal fissure: effect of type D personality

    PubMed Central

    Yilmaz, Edip Erdal; Canan, Fatih; Yildirim, Osman; Cetin, Mehmet Mustafa

    2014-01-01

    Introduction Health-related quality of life (HRQL) is a significant factor in describing the burden of illness and the impact of treatment in patients with gastrointestinal disease. Type D (distressed) personality is defined as the co-occurrence of negative affect and social inhibition. Aim To assess the prevalence of type D personality in patients with anal fissure and to investigate whether the presence of a type D personality would affect HRQL in patients with anal fissure. Material and methods One hundred outpatients with anal fissure with no psychiatric comorbidity were consecutively enrolled, along with 100 healthy controls. Type D Scale (DS14) and General Health Survey Short Form-36 (SF-36) were used in the collection of data. Results Patients with anal fissure scored lower on physical roles and bodily pain dimensions of SF-36 than healthy subjects (p < 0.05). Thirty-three patients with anal fissure (33%) and 16 controls (16%) had scored above the cut-off score of the DS14 (p < 0.05). Patients with a type D personality were found to score lower on bodily pain and social roles domains of HRQL than patients without a type D personality. Conclusions Type D personality was associated with increased perceived bodily pain and social roles in patients with anal fissure. Type D personality construct may be an important consideration when assessing HRQL outcomes. A multidimensional approach may be valuable in the assessment of patients presenting with anal fissure, because a subgroup with type-D personality might benefit from psychological therapies. PMID:25061489

  8. Near-Vent, Fissure-Fed Lava Channel Network Morphologies in the Kīlauea December 1974 Flow: Implications for Differentiating Lava Construction From Fluvial Erosion on Planets

    NASA Astrophysics Data System (ADS)

    Bleacher, J. E.

    2015-12-01

    Streamlined islands are often assumed to be the product of erosion by water and are cited as evidence of aqueous flows on Mars. However, lava can build streamlined islands in a manner that is more easily explained by flow thickening followed by partial drainage of preferred lava pathways. Kīlauea's December 1974 (D1974) flow was emplaced as a broad sheet-like flow from a series of en echelon fissures across an older hummocky pāhoehoe tumulus field. The lavas surrounded the tumuli and coalesced to fill a topographic low near the basal scarp of the Koae Fault System. As these obstacles were inundated by the D1974 flow, the lava preferentially cooled around the tumuli to form a higher viscosity zone beneath a smooth crust. Stagnation of these thinner, cooler, and more viscous zones focused the flow into a series of preferred lava pathways located between the stagnant islands. Changes in the local discharge rate disrupted the crust of the flow above the lower viscosity pathways. Older tumuli adjacent to the D1974 flow display the same relief as the flow's islands and uncovered portions of this older flow are exposed at the tops of many islands, supporting an interpretation that islands were anchored by high-standing pre-flow tumuli. As the local lava supply waned, partial drainage of the preferred pathways occurred between the higher-standing surfaces anchored to the older tumuli. The resulting morphology consists of a relatively smooth flow field with thin margins that is dissected by depressed pathways or channels. This morphology resembles an erosional surface incised into a smooth plain, but actually represents an initial constructional process followed by partial drainage within a viscous lava flow. Many other Hawaiian rift zone, fissure-fed flow fields display comparable morphologies in the near vent facies, including islands, terraces, thin flow margins and a lack of well defined topographic levees along channels. Thus, branching channel networks and

  9. Submarine fissure eruptions and hydrothermal vents on the southern Juan de Fuca Ridge: preliminary observations from the submersible Alvin

    USGS Publications Warehouse

    Normark, W.R.

    1986-01-01

    The submersible Alvin was used to investigate 3 active hydrothermal discharge sites along the S Juan de Fuca Ridge in September 1984. The hydrothermal zones occur within a 10-30m-deep, 30-50m-wide cleft marking the center of the axial valley. This cleft is the eruptive locus for the axial valley. The hydrothermal vents coincide with the main eruptive vents along the cleft. Each hydrothermal zone has multiple discharge sites extending as much as 500m along the cleft. Sulfide deposits occur as clusters (15-100m2 area) of small chimneys (= or <2m high) and as individual and clustered fields of large, branched chimneys (= or <10m high). Recovered sulfide samples are predominantly the tops of chimneys and spires and typically contain more than 80% sphalerite and wurtzite with minor pyrrhotite, pyrite, marcasite, isocubanite, chalcopyrite, anhydrite, anhydrite, and amorphous silica. The associated hydrothermal fluids have the highest chlorinity of any reported to date.-Authors

  10. Anal Fissure

    PubMed Central

    Zaghiyan, Karen N.; Fleshner, Phillip

    2011-01-01

    Anal fissure is one of the most common anorectal problems. Anal fissure is largely associated with high anal sphincter pressures and most treatment options are based on reducing anal pressures. Conservative management, using increased fiber and warm baths, results in healing of approximately half of all anal fissures. In fissures that fail conservative care, various pharmacologic and surgical options offer satisfactory cure rates. Lateral internal sphincterotomy remains the gold standard for definitive management of anal fissure. This review outlines the key points in the presentation, pathophysiology, and management of anal fissure. PMID:22379402

  11. Anal Fissure

    PubMed Central

    Beaty, Jennifer Sam; Shashidharan, M.

    2016-01-01

    Anal fissure (fissure-in-ano) is a very common anorectal condition. The exact etiology of this condition is debated; however, there is a clear association with elevated internal anal sphincter pressures. Though hard bowel movements are implicated in fissure etiology, they are not universally present in patients with anal fissures. Half of all patients with fissures heal with nonoperative management such as high fiber diet, sitz baths, and pharmacological agents. When nonoperative management fails, surgical treatment with lateral internal sphincterotomy has a high success rate. In this chapter, we will review the symptoms, pathophysiology, and management of anal fissures. PMID:26929749

  12. Anal Fissure.

    PubMed

    Beaty, Jennifer Sam; Shashidharan, M

    2016-03-01

    Anal fissure (fissure-in-ano) is a very common anorectal condition. The exact etiology of this condition is debated; however, there is a clear association with elevated internal anal sphincter pressures. Though hard bowel movements are implicated in fissure etiology, they are not universally present in patients with anal fissures. Half of all patients with fissures heal with nonoperative management such as high fiber diet, sitz baths, and pharmacological agents. When nonoperative management fails, surgical treatment with lateral internal sphincterotomy has a high success rate. In this chapter, we will review the symptoms, pathophysiology, and management of anal fissures.

  13. Anal fissure.

    PubMed

    Schlichtemeier, Steven; Engel, Alexander

    2016-02-01

    An anal fissure is a common, mostly benign, condition that can be acute or chronic. The diagnosis is usually made on history and physical examination, but further investigations are sometimes necessary. Primary fissures are usually benign and located in the posterior or anterior position. Secondary fissures are lateral or multiple and often indicate a more serious underlying pathology. The management of primary anal fissures is generally non-operative and includes increased dietary fibre, sitz baths, topical ointments and botulinum toxin injections. If these treatments are ineffective the patient will need a surgical referral. Secondary anal fissures require further investigation. Multidisciplinary management is preferable and is essential in the case of malignancy.

  14. Shallow Subsurface Structures of Volcanic Fissures

    NASA Astrophysics Data System (ADS)

    Parcheta, C. E.; Nash, J.; Mitchell, K. L.; Parness, A.

    2015-12-01

    Volcanic fissure vents are a difficult geologic feature to quantify. They are often too thin to document in detail with seismology or remote geophysical methods. Additionally, lava flows, lava drain back, or collapsed rampart blocks typically conceal a fissure's surface expression. For exposed fissures, quantifying the surface (let along sub0surface) geometric expression can become an overwhelming and time-consuming task given the non-uniform distribution of wall irregularities, drain back textures, and the larger scale sinuosity of the whole fissure system. We developed (and previously presented) VolcanoBot to acquire robust characteristic data of fissure geometries by going inside accessible fissures after an eruption ends and the fissure cools off to <50 C. Data from VolcanoBot documents the fissure conduit geometry with a near-IR structured light sensor, and reproduces the 3d structures to cm-scale accuracy. Here we present a comparison of shallow subsurface structures (<30 m depth) within the Mauna Ulu fissure system and their counterpart features at the vent-to-ground-surface interface. While we have not mapped enough length of the fissure to document sinuosity at depth, we see a self-similar pattern of irregularities on the fissure walls throughout the entire shallow subsurface, implying a fracture mechanical origin similar to faults. These irregularities are, on average, 1 m across and protrude 30 cm into the drained fissure. This is significantly larger than the 10% wall roughness addressed in the engineering literature on fluid dynamics, and implies that magma fluid dynamics during fissure eruptions are probably not as passive nor as simple as previously thought. In some locations, it is possible to match piercing points across the fissure walls, where the dike broke the wall rock in order to propagate upwards, yet in other locations there are erosional cavities, again, implying complex fluid dynamics in the shallow sub-surface during fissure eruptions.

  15. Anal fissure

    PubMed Central

    Schlichtemeier, Steven; Engel, Alexander

    2016-01-01

    SUMMARY An anal fissure is a common, mostly benign, condition that can be acute or chronic. The diagnosis is usually made on history and physical examination, but further investigations are sometimes necessary. Primary fissures are usually benign and located in the posterior or anterior position. Secondary fissures are lateral or multiple and often indicate a more serious underlying pathology. The management of primary anal fissures is generally non-operative and includes increased dietary fibre, sitz baths, topical ointments and botulinum toxin injections. If these treatments are ineffective the patient will need a surgical referral. Secondary anal fissures require further investigation. Multidisciplinary management is preferable and is essential in the case of malignancy. PMID:27041801

  16. Evaluation of different types of enamel conditioning before application of a fissure sealant.

    PubMed

    Ciucchi, Philip; Neuhaus, Klaus W; Emerich, Marta; Peutzfeldt, Anne; Lussi, Adrian

    2015-01-01

    The aim of the study was to compare fissure sealant quality after mechanical conditioning of erbium-doped yttrium aluminium garnet (Er:YAG) laser or air abrasion prior to chemical conditioning of phosphoric acid etching or of a self-etch adhesive. Twenty-five permanent molars were initially divided into three groups: control group (n = 5), phosphoric acid etching; test group 1 (n = 10), air abrasion; and test group 2, (n = 10) Er:YAG laser. After mechanical conditioning, the test group teeth were sectioned buccolingually and the occlusal surface of one half tooth (equal to one sample) was acid etched, while a self-etch adhesive was applied on the other half. The fissure system of each sample was sealed, thermo-cycled and immersed in 5% methylene dye for 24 h. Each sample was sectioned buccolingually, and one slice was analysed microscopically. Using specialized software microleakage, unfilled margin, sealant failure and unfilled area proportions were calculated. A nonparametric ANOVA model was applied to compare the Er:YAG treatment with that of air abrasion and the self-etch adhesive with phosphoric acid (α = 0.05). Test groups were compared to the control group using Wilcoxon rank sum tests (α = 0.05). The control group displayed significantly lower microleakage but higher unfilled area proportions than the Er:YAG laser + self-etch adhesive group and displayed significantly higher unfilled margin and unfilled area proportions than the air-abrasion + self-etch adhesive group. There was no statistically significant difference in the quality of sealants applied in fissures treated with either Er:YAG laser or air abrasion prior to phosphoric acid etching, nor in the quality of sealants applied in fissures treated with either self-etch adhesive or phosphoric acid following Er:YAG or air-abrasion treatment.

  17. Anal fissure

    MedlinePlus

    ... bath 2 to 3 times a day. The water should cover only the hips and buttocks. If the anal fissures do not go away with home care methods, treatment may involve: Botox injections into the muscle in the anus (anal sphincter) ...

  18. Efficacy of lanolin and bovine type I collagen in the treatment of childhood anal fissures: a prospective, randomized, controlled clinical trial.

    PubMed

    Büyükyavuz, Behçet Ilker; Savaş, Cagri; Duman, Levent

    2010-08-01

    We designed an open-labeled, prospective, randomized, controlled clinical trial to test the efficacy of topical lanolin ointment (PureLan) and bovine type I collagen spray (Gelfix) in the treatment of childhood anal fissures. Seventy-one children with acute anal fissure were divided randomly into three groups: group I (control; n = 25), group II (PureLan; n = 28), and group III (Gelfix; n = 18). All children were assigned to have warm sitz baths, topical analgesic creams, and stool softeners. Patients in groups II and III were also treated with topical lanolin ointment and bovine type I collagen, respectively. All children were re-examined 4 weeks later. Complete healing of the anal fissure was observed in 68% of the group I patients, but in 92.9% and 100% of the group II and III patients, respectively. The difference among groups was significant in terms of complete fissure healing (P = 0.003), but the efficacy of topical lanolin ointment and bovine type I collagen spray did not differ significantly (P = 0.078). Our data suggest that topical lanolin ointment and bovine type I collagen spray are effective in the treatment of acute anal fissure in children.

  19. Video Observations by Telepresence Reveal Two Types of Hydrothermal Venting on Kawio Barat Seamount

    NASA Astrophysics Data System (ADS)

    Butterfield, D. A.; Holden, J. F.; Shank, T. M.; Tunnicliffe, V.; Sherrin, J.; Herrera, S.; Baker, E. T.; Lovalvo, D.; Makarim, S.; Malik, M. A.; Wirasantosa, S.; Hammond, S. R.

    2010-12-01

    The INDEX-SATAL 2010 expedition began an international exploration of the seafloor in Indonesian waters using the methodology of telepresence, conducting EM302 multibeam mapping, water column CTD, and ROV high-definition video operations and sending data back to Exploration Command Centers in Indonesia and Seattle. Science observers in other locations in the US and Canada were engaged in real-time observations and interpretation of results. One mission goal was to locate hydrothermal or volcanic activity. Intense light scattering and redox potential measurements in the water column over Kawio Barat (KB)indicated a high level of hydrothermal activity, and direct video observations confirmed venting near the summit. None of the other volcanic features west of the Sangihe arc that were investigated during the mission had confirmed hydrothermal activity. ROV capabilities did not include physical sampling or temperature measurement, so our interpretation is based on visual comparison to other known sites. The steep western flank of KB from 2000 m depth to the summit (1850 m) has many areas of white and orange staining on exposed rocks, with some elemental sulfur, and broad areas covered with dark volcaniclastic sand, but no active venting was seen. KB has a summit ridge running WNW-ESE, with a major cross-cutting ridge on the western portion of the summit. Hydrothermal activity is concentrated near the eastern side of this intersection, on both the northern and southern sides of the summit ridge. Venting on the northern side of the summit ridge is characterized by intense white particle-rich fluids emanating directly from the rocky substrate with frozen flows of elemental sulfur down slope. This type of venting is visually very similar to the venting seen on NW Rota-1, an actively erupting volcano in the Mariana arc, and suggests that KB is actively releasing magmatic gases rich in sulfur dioxide to produce the elemental sulfur flows, inferred fine particulate sulfur

  20. The architecture and shallow conduits of Laki-type pyroclastic cones: insights into a basaltic fissure eruption

    NASA Astrophysics Data System (ADS)

    Reynolds, P.; Brown, R. J.; Thordarson, T.; Llewellin, E. W.

    2016-05-01

    Pyroclastic cones built along basaltic fissures provide important volcanological information, but it is often difficult to examine the early-erupted products due to burial by later products. Furthermore, it is rare to see the link between the feeder dyke and overlying cone fully exposed. In this study, we detail the architecture of a hybrid spatter cone, scoria half-cone and feeder dyke that has been dissected to below the pre-eruption surface by glacial floods. The cones were constructed during the 6-8 ka Rauðuborgir-Kvensöðul fissure eruption in North Iceland during Hawaiian- and Strombolian-style activities. Widening of their feeder dyke in the shallow sub-surface to produce an upward flaring morphology was accommodated by country rock removal and elastic host rock deformation. Ballistic calculations and stratigraphic relationships indicate that the scoria half-cone was constructed early in the eruption from the deposits of a lava fountain ~100 m high. A decline in fountain height and the generation of abundant welded deposits resulted in the formation of a nested spatter cone within the scoria half-cone. The cones are similar in structure and size to the hybrid scoria and spatter cones produced during the 15-km3 1783 Laki eruption and serve as a valuable window into the construction of pyroclastic edifices during basaltic fissure eruptions.

  1. Shear bond strength and microleakage of a self-etching adhesive for fissure sealing after different types of aging.

    PubMed

    Schuldt, Christoph; Birlbauer, Sebastian; Pitchika, Vinay; Crispin, Alexander; Hickel, Reinhard; Kühnisch, Jan

    2016-01-01

    The aim of this study was to evaluate shear bond strength (SBS) and microleakage of a self-etching adhesive (Adper Prompt L-Pop) in comparison to acid etching prior fissure sealing. Each procedure was tested with 3 aging procedures (1-day water storage, 3-month water storage and 1-day water storage/5,000× thermocycling). SBS was determined according to ISO standard 29022. Additional 30 third molars were utilized for the microleakage analyses. Data were analyzed using Mann-Whitney-U-Test and multiple linear regression models. The SBS of the self-etching adhesive were significantly lower (14.9, 11.9, and 13.0 MPa) than those of conventional fissure sealing (19.1, 18.2, and 15.6 MPa). Multiple linear regression models predicted that material and alteration significantly influenced SBS. The microleakage revealed no difference between both groups (1.3% vs. 1.2%). It can be concluded that the selfetching adhesive might be a pre-treatment alternative for fissure sealing in terms of the easier and shorter clinical workflow.

  2. Engineering a robotic approach to mapping exposed volcanic fissures

    NASA Astrophysics Data System (ADS)

    Parcheta, C. E.; Parness, A.; Mitchell, K. L.

    2014-12-01

    Field geology provides a framework for advanced computer models and theoretical calculations of volcanic systems. Some field terrains, though, are poorly preserved or accessible, making documentation, quantification, and investigation impossible. Over 200 volcanologists at the 2012 Kona Chapman Conference on volcanology agreed that and important step forward in the field over the next 100 years should address the realistic size and shape of volcanic conduits. The 1969 Mauna Ulu eruption of Kīlauea provides a unique opportunity to document volcanic fissure conduits, thus, we have an ideal location to begin addressing this topic and provide data on these geometries. Exposed fissures can be mapped with robotics using machine vision. In order to test the hypothesis that fissures have irregularities with depth that will influence their fluid dynamical behavior, we must first map the fissure vents and shallow conduit to deci- or centimeter scale. We have designed, constructed, and field-tested the first version of a robotic device that will image an exposed volcanic fissure in three dimensions. The design phase included three steps: 1) create the payload harness and protective shell to prevent damage to the electronics and robot, 2) construct a circuit board to have the electronics communicate with a surface-based computer, and 3) prototype wheel shapes that can handle a variety of volcanic rock textures. The robot's mechanical parts were built using 3d printing, milling, casting and laser cutting techniques, and the electronics were assembled from off the shelf components. The testing phase took place at Mauna Ulu, Kīlauea, Hawai'i, from May 5 - 9, 2014. Many valuable design lessons were learned during the week, and the first ever 3D map from inside a volcanic fissure were successfully collected. Three vents had between 25% and 95% of their internal surfaces imaged. A fourth location, a non-eruptive crack (possibly a fault line) had two transects imaging the textures

  3. Enceladus Near-Fissure Surface Temperatures

    NASA Astrophysics Data System (ADS)

    Howell, Robert R.; Goguen, J. D.; Spencer, J. R.

    2013-10-01

    Recently reported Cassini VIMS observations of thermal emission from the Enceladus south-pole fissures (Goguen et al. 2013) when combined with previous longer wavelength Cassini CIRS observations (Spencer et al. 2006) allow us to better constrain the highest temperatures present, but also require more detailed modeling of the processes which control those highest temperatures. The simplest interpretation of the VIMS observations is that the 3-5 µm thermal radiation comes from the walls within a fissure, rather than the adjacent surface. But as part of investigating that latter alternative it became clear that very high sublimation rates are implied by some predicted surface temperatures. Abramov and Spencer (2009) produced models of the expected surface temperature distribution, assuming conduction of heat through the ice, balanced by thermal radiation at the surface. However as temperature is raised, at 186K sublimation cooling equals radiation, and because it depends exponentially on temperature, it quickly dominates. We have found that including the surface sublimation cooling suppresses the higher temperatures. Regardless of the fissure temperature, surface temperatures above 200K can only be maintained by conduction within a few tens of centimeters of the assumed fissure wall. The high sublimation erosion rates (0.25 m/yr at 180K, rising to over 100 m/yr at 220K) imply that the fixed boundaries we have previously assumed are unrealistic. If these surface temperatures are maintained then either a sublimation lag of non-ice components will accumulate, inhibiting sublimation, or the geometry of the fissure vent will rapidly change. However the rate of change will be limited by the available heat provided by conduction. We are now developing numerical models with moving boundary conditions to explore the time evolution. The simplest result may be that the lip of the fissure erodes back till it no longer remains in thermal contact with the rising vapor which

  4. Sonar backscatter differentiation of dominant macrohabitat types in a hydrothermal vent field.

    PubMed

    Durand, Sébastien; Legendre, Pierre; Juniper, S Kim

    2006-08-01

    Over the past 20 years, sonar remote sensing has opened ways of acquiring new spatial information on seafloor habitat and ecosystem properties. While some researchers are presently working to improve sonar methods so that broad-scale high-definition surveys can be effectively conducted for management purposes, others are trying to use these surveying techniques in more local areas. Because ecosystem management is scale-dependent, there is a need to acquire spatiotemporal knowledge over various scales to bridge the gap between already-acquired point-source data and information available at broader scales. Using a 675-kHz single-pencil-beam sonar mounted on the remotely operated vehicle ROPOS, 2200 m deep on the Juan de Fuca Ridge, East Pacific Rise, five dominant habitat types located in a hydrothermal vent field were identified and characterized by their sonar signatures. The data, collected at different altitudes from 1 to 10 m above the seafloor, were depth-normalized. We compared three ways of handling the echoes embedded in the backscatters to detect and differentiate the five habitat types; we examined the influence of footprint size on the discrimination capacity of the three methods; and we identified key variables, derived from echoes that characterize each habitat type. The first method used a set of variables describing echo shapes, and the second method used as variables the power intensity values found within the echoes, whereas the last method combined all these variables. Canonical discriminant analysis was used to discriminate among the five habitat types using the three methods. The discriminant models were constructed using 70% of the data while the remaining 30% were used for validation. The results showed that footprints 20-30 cm in diameter included a sufficient amount of spatial variation to make the sonar signatures sensitive to the habitat types, producing on average 82% correct classification. Smaller footprints produced lower percentages of

  5. Posterior fossa decompression combined with resection of the cerebellomedullary fissure membrane and expansile duraplasty: a radical and rational surgical treatment for Arnold-Chiari type I malformation.

    PubMed

    Liang, Chen Jian; Dong, Qiu Jian; Xing, You Heng; Shan, Ma; Wen, Lian Xiao; Qiang, Zhong Yuan; Ping, Zhang Qing; Tao, Peng Zhi; Ping, Huang Xiao

    2014-12-01

    This study aims to introduce a new surgical procedure for the treatment of Arnold-Chiari type I malformation (ACM-1) and to compare its effectiveness with the techniques described in previous studies. We performed the following procedures: foramen magnum decompression combined with the removal of both the atlanto-occipital membrane, extended resection of the cerebellomedullary fissure arachnoid membrane, and artificial duraplasty to enlarge the membranic posterior fossa without resecting the cerebellar tonsils and syringosubarachnoid shunting. There were 21 ACM-1 patients: 12 cases had osteo-compression on the cerebellar hemisphere, 18 cases had thickened adhered fabric ring that stretched from arachnoid membrane to cerebellar hemisphere, and 15 cases with syringomyelia. The patients were followed up for 6 months to 3 years after the surgery. All patients showed a remarkable recovery of syringomyelia. There were no morbidity or death related to the surgery. Most of ACM-1 patients, the osteo- and membrane compression on cerebellar hemisphere and tonsil were observed during the operation. Therefore, decompression of foramen magnum and posterior craniocervical combined with the removal of cerebellomedullary fissure arachnoid membrane and placement of an artificial dural graft should be considered as a comprehensive option of minimally invasive surgery and rational and radical treatment of ACM-1. Our experience showed that, by using our procedure, shunting becomes no longer necessary in the treatment of ACM-1-associated syringomyelia.

  6. Anal fissure - slideshow

    MedlinePlus

    ... this page: //medlineplus.gov/ency/presentations/100154.htm Anal fissure - series—Normal anatomy To use the sharing ... rectum through which passes stool during defecation. The anal sphincter is a critical mechanism for control of ...

  7. High-Temperature Hydrothermal Vent Field of Kolumbo Submarine Volcano, Aegean Sea: Site of Active Kuroko-Type Mineralization

    NASA Astrophysics Data System (ADS)

    Sigurdsson, H.; Carey, S.; Alexandri, M.; Vougioukalakis, G.; Croff, K.; Roman, C.; Sakellariou, D.; Anagnostou, C.; Rousakis, G.; Ioakim, C.; Gogou, A.; Ballas, D.; Misaridis, T.; Nomikou, P.

    2006-12-01

    Kolumbo submarine volcano is located 7 km north-east of the island of Santorini in the Hellenic arc (Greece), and comprises one of about twenty submarine cones in a NE-trending rift zone. Kolumbo erupted explosively in 1649-50AD, causing 70 fatalities on Santorini. Kolumbo's crater is 1700 m in diameter, with a crater rim at 10 m below sea level and crater floor at depth of 505 m. Recent marine geological investigations, using ROVs, reveal a very active high-temperature hydrothermal vent field in the northeastern part of the Kolumbo crater floor, about 25,000 m2. Vent chimneys up to 4 m high are vigorously emitting colorless gas plumes up to 10 m high in the water column. Temperatures up to 220oC are recorded in vent fluids. Some vents are in crater- like depressions, containing debris from collapsed extinct chimneys. The entire crater floor of Kolumbo is mantled by a reddish-orange bacterial mat, and bacterial filaments of a variety of colors cling to chimneys in dense clusters. Glassy tunicates and anemones are common in lower-temperature environments on the crater floor. Most chimneys show a high porosity, with a central conduit surrounded by an open and very permeable framework of sulfides and sulfates, aiding fluid flow through the chimney walls. In the sulfate-rich samples, blades of euhedral barite and anhydrite crystals coat the outside of the chimney wall, and layers of barite alternate with sulfide in the interior. The dominant sulfides are pyrite, sphalerite, wurtzite, marcasite and galena. Crusts on extinct and lower-temperature chimneys are composed of amorphous silica, goethite and halite. Sulfur isotope composition of sulfates is virtually at sea water values, whereas the sulfides are more depleted. Elevated levels of copper, gold and silver are observed in bulk composition of chimney samples. Both the structural setting, character of the vent field and sulfide/sulfate mineralogy and geochemistry indicate on-going Kuroko-type mineralization in the

  8. Vented transmission

    SciTech Connect

    Nguyen, T.H.

    1990-01-29

    This patent describes a vented transmission. It comprises: a housing; a rotary input to the housing; a rotary output from the housing; transmission means within the housing interconnecting the input and the output and including a hollow, rotary shaft journaled within the housing; a vent tube having a first end extending into one end of the hollow shaft and a second end in fluid communication with the exterior of the housing; a shoulder within the hollow shaft and intermediate the ends of the vent tube and defining of relatively smaller diameter section near the first end of the vent tube that is within the hollow shaft and a relatively large diameter section nearer the second end of the vent tube; at least one aperture extending through the hollow shaft from the large diameter section immediately adjacent the shoulder; and a labyrinth seal at the interface of the vent tube and the large diameter section at a location between the aperture (s) and the second end of the vent tube.

  9. Basaltic fissure eruptions, plume heights, and atmospheric aerosols

    NASA Technical Reports Server (NTRS)

    Stothers, R. B.; Wolff, J. A.; Self, S.; Rampino, M. R.

    1986-01-01

    Convective plumes that rise above Hawaiian-style fire fountains consist of volcanic gases, aerosols, fine ash, and entrained heated air. Plume theory has been applied to observational estimates of the rate of thermal energy release from large fire fountains. The theoretically predicted heights of maintained plumes agree very well with the heights found from actual observations. Predicted plume heights for both central-vent (point-source) and fissure (line-source) eruptions indicate a stratospheric penetration by plumes that form over vents with very high magma-production rates. Flood basalt fissure eruptions that produce individual lava flows with volumes greater than 100 cu km at very high mass eruption rates are capable of injecting large quantities of sulfate aerosols into the lower stratosphere, with potentially drastic short-term atmospheric consequences, like acid precipitation, darkening of the sky, and climatic cooling.

  10. Influence of Geologic Setting on the Morphology, Mineralogy, and Geochemistry of Vent Deposits Along the Eastern Lau Spreading Center and Valu Fa Ridge

    NASA Astrophysics Data System (ADS)

    Tivey, M. K.; Evans, G. N.; Ferrini, V. L.

    2014-12-01

    Establishment of links between lithology, vent fluid chemistry, and vent deposit characteristics along the Eastern Lau Spreading Center (ELSC) and Valu Fa Ridge (VFR) was made possible using deep submergence vehicles and technology. ROV Jason was used to collect ultrahigh-resolution (submeter) bathymetric data sufficient to quantify characteristics of volcanic, tectonic and hydrothermal features; differences within vent fields from north to south include a change from low-relief volcanic domes cut by faults and fissures to higher aspect ratio volcanic domes dominated by aa-type lava morphologies (Ferrini et al., G-cubed, 2008). Highest temperature fluids are associated with crosscutting faults at all but Mariner vent field where faults are not observed. The detailed maps were used to target areas within vent fields for observations and sampling. Vent deposit morphologies are similar at the northernmost vent fields (Kilo Moana, TowCam, Tahi Moana), with black smokers and diffusers present on branched edifices. Vent deposits at the more southerly ABE, Tui Malila and Mariner vent fields vary in morphology, despite similar substrate lithology. Examples include abundant flanges at ABE and Tui Malila and ~20m-tall spires and squat barite-rich edifices at Mariner. Geochemical analyses and petrographic observations document the influence of lithology, fluid temperature, pH, and extents of seawater mixing on deposit formation. Concentrations of As, which increase from north to south, reflect lithologic control. Sb, Pb, and Ba concentrations also reflect lithologic control, but are affected as well by low pH and/or extents of seawater mixing. The significant differences in Mariner deposits reflect formation from very high temperature, low pH (<3 vs >4) fluids that keep Zn in solution, combined with local subsurface mixing. Overall, results document the influence of the Tonga Subduction Zone on vent deposits through its affects on lithology and vent fluid composition.

  11. A Geophysical Study of Fissures in Pahrump, Nevada

    NASA Astrophysics Data System (ADS)

    Hirsch, A. C.; McEwan, M. J.; Howley, R. A.; Mehling, J. B.; Snelson, C. M.; Drohan, P.

    2004-12-01

    Earth fissures are surface expressions of deep fracturing subsidence systems caused by groundwater withdrawl greater than aquifer recharge. This type of subsidence is most common in arid environments of the south western U.S. such as, Las Vegas, NV, Phoenix, AZ, and areas in New Mexico. In addition, fissures have recently been identified in the Pahrump Valley in southwestern Nevada just west of Las Vegas. The city of Pahrump has experienced an increase in population and economic growth. This growth has lead to a higher demand in the use of the areas natural resources. One major concern is groundwater pumping and over-watering of the land surface. Pahrump has experienced significant differential subsidence within the valley causing significant structural damage to infrastructure. This differential subsidence is most readily identified by its surface expression as fissures. Earth fissures are not only shallow surface features but can be 10's of meters deep and 100's of meters long. These ground failures can be exacerbated by faults at depth, shallow bedrock, and/or differential compaction. However, the most significant cause is from groundwater withdrawl. Several geophysical methods were performed on the fissures to better understand their subsurface expression, trend, and ultimately their affect on the city of Pahrump. Seismic refraction, reflection, ground penetrating radar (GPR), and gravity measurements were performed on the fissures and surrounding area including local faults. Our initial studies show the fissures propagating for long distances, in a variety of shapes, and trending in a north-south direction. Initial GPR studies show high fissure reflections at approximately 1 and 1.5 meters along with general slumping features below these reflections. Fissures are an unmitigatable problem. Our results will help identify fissures in the area that do not have a surface expression as well as mapping the current fissures and their extent. These results can be used

  12. 24 CFR 3280.611 - Vents and venting.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... this section and as otherwise required by this standard. (b) Materials—(1) Pipe. Vent piping shall be... listed materials. (2) Fittings. Appropriate fittings shall be used for all changes in direction or size and where pipes are joined. The material and design of vent fittings shall conform to the type...

  13. Current concepts in anal fissures.

    PubMed

    Ayantunde, Abraham A; Debrah, Samuel A

    2006-12-01

    Anal fissure is a common and distressing problem the true incidence of which is probably higher than recorded. There is a progressive understanding of the etiopathogenesis of this entity and the changing trend in its management approach. This is a systematic review of available published literature looking at current management options in anal fissures. A MEDLINE-based search of the relevant literature from 1970 to 2004 was performed on the current concepts in etiopathogenesis and management of anal fissure. The current opinion is a drift toward conservative measures as the first- and second-line approaches rather than surgery for treatment of anal fissure. Simple and readily available measures with less complication, good patient compliance, and satisfaction requiring no hospitalization should first be considered. Most anal fissures heal with medical therapy, but their limitations include side effects, poor compliance, and recurrence of the fissure. A cautious surgical approach is required to treat those who do not respond to medical therapy.

  14. Video monitoring analysis of the dynamics at fissure eruptions

    NASA Astrophysics Data System (ADS)

    Witt, Tanja; Walter, Thomas R.

    2016-04-01

    At basaltic eruption often lava fountains occur. The fountains mainly develop at erupting fissures, underlain by a magma-filled dike transporting the magma horizontally and vertically. Understanding of the dynamics of the deep dike and fracture mechanisms are mainly based on geophysical data as well as observations from seismic or geodetic networks. At the surface, however, new methods are needed to allow detailed interpretation on the eruption velocities, interactions between vents and complexities in the magma paths. With video cameras we collected imaging data from different erupting fissures. We find that lava fountaining is often correlated at distinct vents. From the frames of the videos we calculated the height and velocities of fountains as a function of time. Lava fountains often show a pulsating regime, that may change over time. Comparing the fountain height as a function of time of different vents by an time-dependent cross-correlation, we find a time lag between the pulses at adjacent vents. From this we derive an apparent velocity of temporal separation between vents, associated with the fountaining activity based on the calculated time lag and the vent distances. Although the correlation system can change episodically and sporadically, both the frequency of the fountains and eruption and the rest time between single fountains remain remarkably similar for adjacent lava fountains imply a controlling process in the magma feeder system itself. We present and compare our method for the Kamoamoa eruption 2011 (Hawaii) and the Holuhraun eruption 2014/2015 (Iceland). Both sites show a significant time shift between the single pulses of adjacent vents. We compare our velocities determined by this time shift to the assumed magma flow velocity in the dike as determined by independent models. Therefore we conjecture that the time shift of venting activity may allow to estimate the dynamics of magma and fluid migration at depth, as well as to identify the

  15. Vented Capacitor

    DOEpatents

    Brubaker, Michael Allen; Hosking, Terry Alan

    2006-04-11

    A technique of increasing the corona inception voltage (CIV), and thereby increasing the operating voltage, of film/foil capacitors is described. Intentional venting of the capacitor encapsulation improves the corona inception voltage by allowing internal voids to equilibrate with the ambient environment.

  16. Fissure seal or fluoride varnish?

    PubMed

    Deery, Christopher

    2016-09-01

    Data sourcesCochrane Oral Health Group Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), Medline, Embase, the US National Institutes of Health Trials Register and the World Health Organization (WHO) Clinical Trials Registry PlatformStudy selectionRandomised controlled trials (RCTs) with at least 12 months follow-up, in which fissure sealants, or fissure sealants together with fluoride varnishes, were compared with fluoride varnishes alone for preventing caries in occlusal surfaces of permanent teeth of children and adolescents.Data extraction and synthesisTwo reviewers independently screened search results, extracted data and assessed risk of bias of included studies. Studies were grouped and analysed on the basis of sealant material type (resin-based sealant and glass ionomer-based sealant, glass ionomer and resin-modified glass ionomer) and different follow-up periods. Odds ratio were calculated for caries or no caries on occlusal surfaces of permanent molar teeth. Mean differences were calculated for continuous outcomes and data. Evidence quality was assessed using GRADE (Grades of Recommendation, Assessment, Development and Evaluation) methods.ResultsEight RCTs involving a total of 1747 children aged five to ten years of age were included. Three trials compared resin-based fissure sealant versus fluoride varnish. Results from two studies (358 children) after two years were combined. Sealants prevented more caries, pooled odds ratio (OR) = 0.69 (95%CI; 0.50 to 0.94). One trial with follow-up at four and nine years found that the caries-preventive benefit for sealants was maintained, with 26% of sealed teeth and 55.8% of varnished teeth having developed caries at nine years. Evidence for glass-ionomer sealants was of low quality. One split-mouth trial analysing 92 children at two-year follow-up found a significant difference in favour of resin-based fissure sealant together with fluoride varnish compared with fluoride varnish only (OR

  17. Fissure eruptions at Mount Vesuvius (Italy): Insights on the shallow propagation of dikes at volcanoes

    NASA Astrophysics Data System (ADS)

    Acocella, Valerio; Porreca, Massimiliano; Neri, Marco; Mattei, Massimo; Funiciello, Renato

    2006-08-01

    Fissure eruptions may provide important information on the shallow propagation of dikes at volcanoes. Somma-Vesuvius (Italy) consists of the active Vesuvius cone, bordered to the north by the remnants of the older Somma edifice. Historical chronicles are considered to define the development of the 37 fissure eruptions between A.D. 1631 and 1944. The 1631 fissure, which reopened the magmatic conduit, migrated upward and was the only one triggered by the subvertical propagation of a dike. The other 25 fissure eruptions migrated downward, when the conduit was open, through the lateral propagation of radial dikes. We suggest two scenarios for the development of the fissures. When the summit conduit is closed, the fissures are fed by vertically propagating dikes. When the summit conduit is open, the fissures are fed by laterally propagating dikes along the volcano slopes. Consistent behaviors are found at other composite volcanoes, suggesting a general application to our model, independent of the tectonic setting and composition of magma. At Vesuvius, the historical data set and our scenarios are used to predict the consequences of the emplacement of fissures after the opening of the conduit. The results suggest that, even though the probability of opening of vents within the inhabited south and west slopes is negligible, the possibility that these are reached by a lava flow remains significant.

  18. Eruption Conditions During Fissure Eruptions in Tharsis, Mars.

    NASA Astrophysics Data System (ADS)

    Wilson, L.; Mouginis-Mark, P. J.; Tyson, S.; Mackown, J.; Garbeil, H.

    2008-12-01

    We focus on six separate, but physically close, vent systems in eastern Tharsis, Mars, just to the east of the volcano Jovis Tholus. The vents are typically linear fissures a few to 20 km in length that have built small shields rising to 50-85 m above the level of the surrounding topography. Typical lengths of individual lava flows from these fissures are 15-20 km, with a maximum of 30 km. Mapping of the vent complexes reveals smooth material, interpreted to be spatter from fire fountaining, located on the rims of some of the fissures. In some places this spatter fed individual short (less than 5 km) lava flows; elsewhere spatter from segments of the fissure coalesced to form longer flows. Temporal evolution of the flow fields is indicated: the oldest parts of the basement at each center are built from a series of compound flows that cannot be subdivided into individual flows. In places activity was locally focussed and formed lava ponds and channelized flows from central vents. MOLA topographic data and photoclinometry topographic profiles made from THEMIS VIS images show that the flows are typically less than 5 m thick, 8-15 times thinner than flows elsewhere on Mars. We used standard models of magma rise through dikes, lava flow emplacement, and fire-fountain behavior to find lava viscosities and yield strengths (100 Pa s and 100 Pa, respectively), eruption rates (5,000 m3/s), flow speeds (1-2 m/s), durations of emplacement of individual flow units (5 hours), and an equivalent magma water content (0.1-0.2 mass percent). These eruption conditions are consistent with a wide range of possible depths of the magma reservoirs feeding the eruptions. Small vents like those studied here have been identified elsewhere in Tharsis (particularly just to the east of Olympus Mons), and the eruption conditions described above may characterize a previously poorly recognized style of volcanism on Mars only identifiable in images with spatial resolutions better than 10 m/pixel.

  19. The pattern of circumferential and radial eruptive fissures on the volcanoes of Fernandina and Isabela islands, Galapagos

    USGS Publications Warehouse

    Chadwick, W.W.; Howard, K.A.

    1991-01-01

    Maps of the eruptive vents on the active shield volcanoes of Fernandina and Isabela islands, Galapagos, made from aerial photographs, display a distinctive pattern that consists of circumferential eruptive fissures around the summit calderas and radial fissures lower on the flanks. On some volcano flanks either circumferential or radial eruptions have been dominant in recent time. The location of circumferential vents outside the calderas is independent of caldera-related normal faults. The eruptive fissures are the surface expression of dike emplacement, and the dike orientations are interpreted to be controlled by the state of stress in the volcano. Very few subaerial volcanoes display a pattern of fissures similar to that of the Galapagos volcanoes. Some seamounts and shield volcanoes on Mars morphologically resemble the Galapagos volcanoes, but more specific evidence is needed to determine if they also share common structure and eruptive style. ?? 1991 Springer-Verlag.

  20. New volcanogenic-eruptive genetic type of diamond occurrence (based on studying the 2012-2013 Fissure Tolbachik Eruption in Kamchatka)

    NASA Astrophysics Data System (ADS)

    Karpov, Gennady; Anikin, Leonid; Filatov, Stanislav; Silaev, Valery; Petrovsky, Vitaly; Zolotarev, Andrey; Dunin-Barkovsky, Romuald; Volynets, Anna

    2014-05-01

    During the 2012-2013 Fissure Tolbachik eruption, diamonds were found both in fresh pyroclastics and in the effusive lava pores. Lavas are aphyric and subaphyric porous aluminous basaltic trachyandesites with rare megacrysts and subphenocrysts of plagioclase, olivine and pyroxene. Groundmass is hyalopilitic, pilotaxitic, occasionally hyaline, with abundant plagioclase microlites. So far, over 750 diamond grains have been found sized mostly 100-500 mkm. Generally, grains are well formed isometric, plane-faced and sharp-edged monocrystals of cubic-octahedral habit and green color, rarer colorless. Faces of rhombic-dodecahedron, tetragonal-trisoctahedron and trigonal-trisoctahedron also occur. Crystal cubic faces host pits of diffusive depletion, and pits with induction surfaces formed after the breakoff of syngenetic inclusions. Octahedral faces often show pyramidal etching pits formed at the dislocation outcrops. Pits contain coatings whose composition includes Fe, Mg, Ca, Si, and Cu-Sn (Zn) alloy films. Diamond X-ray diffraction data (Bruker APEX DUO, STOE IPDS II, MoKα-radiation, 788 reflections) show space group Fd-3m, cubic unit cell parameter a = 3.574(3) A and major reflections (111), (220), (311) etc. at Gandolfi pattern. Raman spectra with red beam reveal only one strong line at 1332 cm-1 typical for diamonds. Spectra excited by the 785 nm beam reveal a wide line with the peak at 1370 cm-1, whose intensity oscillates from 1% to 70% of the diamond line intensity at 1332 cm-1. Infrared absorption spectra reflect two lines with peaks at 1345 and 1130 cm-1, corresponding to structural C-defects (isolated N atoms). Partially, these defects occur in the positive charge state - N+. Structural nitrogen concentration in the form of C-defects varies from 150 to 500 ppm, while that in the form of N+ - from 10 to 30 ppm. Lines of infrared absorption on A and B1 nitrogen defects, as well as those on hydrogen defects typical for most natural diamonds, are not detected for

  1. Growing Hemorrhagic Choroidal Fissure Cyst

    PubMed Central

    Gelal, Fazıl; Gurkan, Gokhan; Feran, Hamit

    2016-01-01

    Choroidal fissure cysts are often incidentally discovered. They are usually asymptomatic. The authors report a case of growing and hemorrhagic choroidal fissure cyst which was treated surgically. A 22-year-old female presented with headache. Cranial MRI showed a left-sided choroidal fissure cyst. Follow-up MRI showed that the size of the cyst had increased gradually. Twenty months later, the patient was admitted to our emergency department with severe headache. MRI and CT showed an intracystic hematoma. Although such cysts usually have a benign course without symptoms and progression, they may rarely present with intracystic hemorrhage, enlargement of the cyst and increasing symptomatology. PMID:26962426

  2. Hyrtl fissure: a historical thriller.

    PubMed

    Mudry, Albert

    2009-06-01

    Hyrtl fissure is an anatomic landmark allowing a transient embryonic communication between the subarachnoid space and the middle ear. It is an eponym characterized by the absence of a known original description. The aim of this study was to try to find and explain the origin of the use of this eponym. Numerous references and original publications were studied to finally demonstrate that Joseph Hyrtl was not able to describe this fissure in the mid-19th century.

  3. [Perianal fistula and anal fissure].

    PubMed

    Heitland, W

    2012-12-01

    CRYPTOGLANDULAR ANAL FISTULA: Perianal abscesses are caused by cryptoglandular infections. Not every abscess will end in a fistula. The formation of a fistula is determined by the anatomy of the anal sphincter and perianal fistulas will not heal on their own. The therapy of a fistula is oriented between a more aggressive approach (operation) and a conservative treatment with fibrin glue or a plug. Definitive healing and the development of incontinence are the most important key points. ANAL FISSURES: Acute anal fissures should be treated conservatively by topical ointments, consisting of nitrates, calcium channel blockers and if all else fails by botulinum toxin. Treatment of chronic fissures will start conservatively but operative options are necessary in many cases. Operation of first choice is fissurectomy, including excision of fibrotic margins, curettage of the base and excision of the sentinel pile and anal polyps. Lateral internal sphincterotomy is associated with a certain degree of incontinence and needs critical long-term observation.

  4. Gas venting system

    DOEpatents

    Khan, Amjad; Dreier, Ken Wayne; Moulthrop, Lawrence Clinton; White, Erik James

    2010-06-29

    A system to vent a moist gas stream is disclosed. The system includes an enclosure and an electrochemical cell disposed within the enclosure, the electrochemical cell productive of the moist gas stream. A first vent is in fluid communication with the electrochemical cell for venting the moist gas stream to an exterior of the enclosure, and a second vent is in fluid communication with an interior of the enclosure and in thermal communication with the first vent for discharging heated air to the exterior of the enclosure. At least a portion of the discharging heated air is for preventing freezing of the moist gas stream within the first vent.

  5. Comparison of short-term in vitro fluoride release and recharge from four different types of pit-and-fissure sealants.

    PubMed

    Koga, Hiroshi; Kameyama, Atsushi; Matsukubo, Takashi; Hirai, Yoshito; Takaesu, Yoshinori

    2004-08-01

    The purpose of this in vitro study was to assess the effects of four commercial fluoride-containing pit-and-fissure sealants on caries prevention. Four sealants containing fluoride, Fuji III, Fuji III LC (GC Co., Tokyo), Teethmate F-1 (Kuraray Medical Co., Osaka) and Helioseal F (Vivadent Co., Liechtenstein) were used to investigate fluoride release and recharge. Disk-shaped specimens prepared from each material were immersed in distilled water at a temperature of 37 degrees C. After seven days, acidulated phosphate fluoride solution (APF) was applied to each specimen, and it was then again immersed in distilled water for 14 days. We then determined how much fluoride had been released into the immersing water. Fuji III LC was used with APF solution to investigate the fluoride uptake. Fuji III had the highest fluoride release, and Fuji III LC had the highest fluoride recharge. Helioseal F and Teethmate F-1 had almost no fluoride recharge. Fuji III LC/APF had a higher fluoride uptake to enamel than Fuji III LC. These results suggest that GIC-sealants in the oral cavity can serve as a fluoride reservoir and contribute to retaining a low fluoride level in oral fluids, thereby preventing caries.

  6. 'Frozen finger' in anal fissures.

    PubMed

    Chintamani; Tandon, Megha; Khandelwal, Rohan

    2009-10-01

    Acute anal fissures are usually managed by various invasive and non-invasive modalities ranging from simple lifestyle changes to chemical and surgical sphincterotomies. Frozen finger, prepared using a water-filled ordinary rubber glove, was successfully used in one hundred patients, thus providing a cost-effective and simple solution to the problem.

  7. Laser fluorescence detection of demineralization in artificial occlusal fissures.

    PubMed

    Ferreira Zandoná, A G; Analoui, M; Schemehorn, B R; Eckert, G J; Stookey, G K

    1998-01-01

    Laser fluorescence (LF) has been used previously to detect early smooth-surface lesions. Although its use for detection of occlusal demineralization has been implicated, it has not been demonstrated. The aim of this study was to determine whether LF could detect demineralization in the base of artificial fissures. To employ LF for detection of occlusal demineralization an apparatus was devised to direct laser light into fissures and simultaneously detect fluorescence from the base of the fissures. Three groups (n = 40/group) of differing fissure types were prepared (straight wall, converging and diverging wall) with either a sound or lesioned base. One half of each group was examined with LF and dye-enhanced LF (DELF); the other half was examined with LF, exposed to plaque, examined with LF and DELF, air-polished and examined with DELF. All images were scored twice as either (1) carious; (2) sound, or (3) undetermined, by a group of 3 examiners. For fissures without plaque, the average sensitivity was higher for DELF (0.76) than for LF (0.54) (p < 0.05). Likewise, the average specificity was higher for DELF (0.64) than for LF (0.29) (p < 0.05). In the presence of plaque, sensitivity was higher for DELF (0.91) compared to LF (0.43); however, specificity was lower for DELF (0.05) compared to LF (0.55). When the fissures were air-polished and then examined with DELF, sensitivity averaged 0.82 (p < 0.05), and specificity increased consistently (average 0.51, p < 0.05). It was concluded that, in the absence of plaque, DELF was a better diagnostic tool than LF for detection of demineralization in artificial fissures.

  8. Research of features related to land subsidence and ground fissure disasters in the Beijing Plain

    NASA Astrophysics Data System (ADS)

    Yang, Y.; Luo, Y.; Liu, M.; Wang, R.; Wang, H.

    2015-11-01

    This study overviews the development history, current situation, impact, and hazards of land subsidence and ground fissure disasters in the Beijing Plain (BP) and focuses on the disaster distribution and features of disaster-causing mechanisms. Currently, the BP is still in a rapid developmental stage of land subsidence. The development and distribution of land subsidence are affected by various factors including the thickness of Quaternary compressible clay, groundwater overexploitation, and the rapid development of urban construction. The causes of ground fissures in the BP are complex and diverse, with evidence of structure fissures, non-structure fissures, and mixed genesis fissures. Investigations of the Gaoliying ground fissure have shown that this fissure has evidence of fracture activity, with vertical deformation that is more significant than horizontal deformation. Furthermore, this ground fissure has characteristics of inter-annual periodicity and annual jumping. The land subsidence and ground fissures are all under structural control and impact each other, and more severe hazards may be induced under the superimposition of these two types of disasters. Effective measures and suggestions for disaster prevention and control are recommended on the basis of this study.

  9. Repeat terrestrial lidar mapping of the new volcanic vent at Holuhraun, Iceland

    NASA Astrophysics Data System (ADS)

    Richardson, J. A.; Whelley, P.; Sutton, S.; Needham, D. H.; Byrne, S.; Hamilton, C.

    2016-12-01

    The locations and morphologies of volcanic vents are essential observations that inform models of volcanic processes on Earth and other planets. Post-eruption morphologic changes at vents are important to characterize in order to more confidently use data gathered from mapping volcanic terrains. We present two terrestrial lidar surveys of the recently formed volcanic vent that fed the Holuhraun lava flow in the Northeastern Region of Iceland. While many studies have measured erosion rate at older volcanic vents, these surveys were performed 6 and 18 months after the end of the eruption and present an opportunity to measure morphologic changes at a brand-new vent. The Holuhraun eruption began in August 2014 by effusing lava through a fissure and continued until February 2015, emplacing approximately 1.4 km³ of lava over nearly 85 km². During the eruption the predominant activity at the northern end of the fissure produced a large (50 m high, 500 m long) cinder-canyon with scoria covered flanks. Lava ponded within this vent and drained to form a primary channel to the northeast. As lava drained through the channel, high stands of lava were preserved as "bathtub rings" on the walls of the vent. Following the cessation of activity at Holuhraun, two lidar surveys were carried out inside the vent, in August 2015 and August 2016. A Riegl VZ-400 scanner was used to collect the point cloud data, which give a precise 3D model of the vent with relative accuracy of 15 cm between scan positions. Differences between the two 3D point clouds are used to distinguish between flow emplacement and post-flow modifications to the surface, and to quantify the surface erosion rate experienced by the young vent. Near-infrared (1550 nm wavelength) reflectance values can also be correlated to lava textures and materials within the vent, providing additional information about how the vent was built syn-eruption and how it degrades post-eruption.

  10. Testing Geyser Models using Down-vent Data

    NASA Astrophysics Data System (ADS)

    Wang, C.; Munoz, C.; Ingebritsen, S.; King, E.

    2013-12-01

    Geysers are often studied as an analogue to magmatic volcanoes because both involve the transfer of mass and energy that leads to eruption. Several conceptual models have been proposed to explain geyser eruption, but no definitive test has been performed largely due to scarcity of down-vent data. In this study we compare simulated time histories of pressure and temperature against published data for the Old Faithful geyser in the Yellowstone National Park and new down-vent measurements from geysers in the El Tatio geyser field of northern Chile. We test two major types of geyser models by comparing simulated and field results. In the chamber model, the geyser system is approximated as a fissure-like conduit connected to a subsurface chamber of water and steam. Heat supplied to the chamber causes water to boil and drives geyser eruptions. Here the Navier-Stokes equation is used to simulate the flow of water and steam. In the fracture-zone model, the geyser system is approximated as a saturated fracture zone of high permeability and compressibility, surrounded by rock matrix of relatively low permeability and compressibility. Heat supply from below causes pore water to boil and drives geyser eruption. Here a two-phase form of Darcy's law is assumed to describe the flow of water and steam (Ingebritsen and Rojstaczer, 1993). Both models can produce P-T time histories qualitatively similar to field results, but the simulations are sensitive to assumed parameters. Results from the chamber model are sensitive to the heat supplied to the system and to the width of the conduit, while results from the fracture-zone model are most sensitive to the permeability of the fracture zone and the adjacent wall rocks. Detailed comparison between field and simulated results, such as the phase lag between changes of pressure and temperature, may help to resolve which model might be more realistic.

  11. Hawaiian fissure fountains 1: decoding deposits-episode 1 of the 1969-1974 Mauna Ulu eruption

    USGS Publications Warehouse

    Parcheta, C.E.; Houghton, B.F.; Swanson, D.A.

    2012-01-01

    Deposits from episode 1 of the 1969–1974 Mauna Ulu eruption of Kīlauea provide an exceptional opportunity to study processes of low intensity Hawaiian fissure fountains. Episode 1 lava flows passed through dense forest that had little impact on flow dynamics; in contrast, the pattern of spatter preservation was strongly influenced by the forest (through the formation of tree molds) and the preexisting topography. A low, near-continuous spatter rampart is present upwind and upslope, on the north side of the fissure. Most of the pyroclastic products, however, fell downwind to the south of the fissure, but little was preserved due to two processes: (1) incorporation of proximal spatter in rheomorphic lava flows 10–20 m from the vents, and (2) the downslope transport of cooler spatter falling on top of these flows beyond 20 m from vent. The lava flow field itself shows a complex history. Initially, discharge from the fissure exceeded the transport capacity of the southern drainage pathways, and lava ponded dynamically to a maximum height of 4 m for 40–120 min, until fountains began to decline. During declining discharge, lava flowed both southward away from the fissure and increasingly back into the vents. There is a clear “lava-shed” or delineation between where lava drained northwards back into the fissure, and where it continued flowing to the south. The 1969 deposits suggest that care is needed when products of less well-documented eruptions are analyzed, as postdepositional transport of spatter may preclude the formation of classic paired (symmetrical) ramparts.

  12. Hyper Vent-ilating

    NASA Image and Video Library

    2015-04-13

    This series of oblique images highlight the wall and exterior of the beautiful volcanic vent located to the northeast of Rachmaninoff basin and west of Copland crater. Layering can be seen along a portion of the wall and the exterior is smooth due to a blanket of fine particles of lava that were ejected explosively from the vent in a pyroclastic eruption. This vent is deeper than Earth's Grand Canyon. http://photojournal.jpl.nasa.gov/catalog/PIA19282

  13. Sensing deep extreme environments: the receptor cell types, brain centers, and multi-layer neural packaging of hydrothermal vent endemic worms.

    PubMed

    Shigeno, Shuichi; Ogura, Atsushi; Mori, Tsukasa; Toyohara, Haruhiko; Yoshida, Takao; Tsuchida, Shinji; Fujikura, Katsunori

    2014-01-01

    Deep-sea alvinellid worm species endemic to hydrothermal vents, such as Alvinella and Paralvinella, are considered to be among the most thermotolerant animals known with their adaptability to toxic heavy metals, and tolerance of highly reductive and oxidative stressful environments. Despite the number of recent studies focused on their overall transcriptomic, proteomic, and metabolic stabilities, little is known regarding their sensory receptor cells and electrically active neuro-processing centers, and how these can tolerate and function in such harsh conditions. We examined the extra- and intracellular organizations of the epidermal ciliated sensory cells and their higher centers in the central nervous system through immunocytochemical, ultrastructural, and neurotracing analyses. We observed that these cells were rich in mitochondria and possessed many electron-dense granules, and identified specialized glial cells and serial myelin-like repeats in the head sensory systems of Paralvinella hessleri. Additionally, we identified the major epidermal sensory pathways, in which a pair of distinct mushroom bodies-like or small interneuron clusters was observed. These sensory learning and memory systems are commonly found in insects and annelids, but the alvinellid inputs are unlikely derived from the sensory ciliary cells of the dorsal head regions. Our evidence provides insight into the cellular and system-wide adaptive structure used to sense, process, and combat the deep-sea hydrothermal vent environment. The alvinellid sensory cells exhibit characteristics of annelid ciliary types, and among the most unique features were the head sensory inputs and structure of the neural cell bodies of the brain, which were surrounded by multiple membranes. We speculated that such enhanced protection is required for the production of normal electrical signals, and to avoid the breakdown of the membrane surrounding metabolically fragile neurons from oxidative stress. Such pivotal

  14. A One-Year Evaluation of a Free Fissure Sealant Program.

    PubMed

    M, Bakhtiar; N, Azadi; A, Golkari

    2016-12-01

    Pit and fissure sealant therapy has been approved as an effective measure in the prevention of occlusal dental caries. Resin based materials are the most common materials used worldwide. A variety of resin based fissure sealants are produced and used. Most of them have been presented with ideal results in research environment. However, their effectiveness in the real life, especially in a mass application program such as Iran's oral health reform plan is not clear. To evaluate the longevity of different fissure sealant applied in Iran's oral health reform plan in Fars Province (south of Iran) after one year. Seven counties were selected. One hundred 6- to 8-year-old school children who had undergone fissure sealant therapy in spring 2015 were randomly selected from each county. Their first molars were examined to evaluate the status of the fissure sealants which were applied one year ago. Data on the type/brand of fissure sealant materials, type and experience of clinicians who applied them, existence of a chair-side assistant, and whether the children were caries-free at the time of fissure sealant application were collected from the existing reports. Data of 1974 teeth from 598 children were used for the final analysis. The effects of type/brand of the material was significant on the final results and remained significant (p < 0.001) after adjustments for the level of fluoride, urban/rural area, upper/lower jaw, type of clinician who applied the sealant, existence of a chair-side assistant, and child's gender, age, and being caries-free. Many factors affect the success rate of a fissure sealant therapy program. The type/brand of the material remained significantly related to the success rate of the fissure sealant even after adjustments for other influencing factors. In this study, ClinproTM Sealant (3M/ESPE, USA) showed better longevity after one year of application.

  15. Hydrothermal vents of Yellowstone Lake, Yellowstone National Park, Wyoming

    SciTech Connect

    Kaplinski, M.A.; Morgan, P. . Geology Dept.)

    1993-04-01

    Hydrothermal vent systems within Yellowstone Lake are located within the Yellowstone caldera in the northeastern and West Thumb sections of the lake. The vent systems lie within areas of extremely high geothermal gradients (< 1,000 C/km) in the lake sediments and occur as clusters of individual vents that expel both hydrothermal fluids and gas. Regions surrounding the vents are colonized by unique, chemotropic biologic communities and suggest that hydrothermal input plays an important role in the nutrient dynamics of the lake's ecosystem. The main concentration of hydrothermal activity occurs in the northeast region of the main lake body in a number of locations including: (1) along the shoreline from the southern edge of Sedge Bay to the inlet of Pelican Creek; (2) the central portion of the partially submerged Mary Bay phreatic explosion crater, within deep (30--50 m) fissures; (3) along the top of a 3 km long, steep-sided ridge that extends from the southern border of Mary Bay, south-southeast into the main lake basin; and (4) east of Stevenson Island along the lower portion of the slope (50--107 m) into the lake basin, within an anastomosing series of north to northwest trending, narrow troughs or fissures. Hydrothermal vents were also located within, and surrounding the West Thumb of Yellowstone Lake, with the main concentration occurring the offshore of the West Thumb and Potts Geyser Basin. Hydrothermal vents in Yellowstone Lake occur along fractures that have penetrated the lake sediments or along the tops of ridges and near shore areas. Underneath the lake, rising hydrothermal fluids encounter a semi-permeable cap of lake sediments. Upwardly convecting hydrothermal fluid flow may be diverted by the impermeable lake sediments along the buried, pre-existing topography. These fluids may continue to rise along topography until fractures are encountered, or the lake sediment cover is thinned sufficiently to allow egress of the fluids.

  16. Possible evidence for on-going volcanism on Mars as suggested by thin, elliptical sheets of low-albedo particulate material around pits and fissures close to Cerberus Fossae

    NASA Astrophysics Data System (ADS)

    Roberts, Gerald Patrick; Crawford, Ian A.; Peacock, David; Vetterlein, Joyce; Parfitt, Elisabeth; Bishop, Louise

    2007-10-01

    We describe 100 200 metre-sized low-albedo haloes from Mars Orbiter Camera (MOC) images, located around sunken pits in the vicinity of Cerberus Fossae, Mars, a fissure-vent system that has been suggested to have been volcanically active within the last few million years. Two types of pit have been identified: (1) lenticular/elongate pits located on the floors of fissures/graben, some of which lead to the summit of a volcano; (2) sub-circular pits, lacking the raised rims expected of impact craters, located either within small lava flows, along fissures, or on flat, cratered plains. The low-albedo haloes encircle the pits, and are in places asymmetric in plan-view, exhibiting almost perfect elliptical outlines with low-aspect ratios, and lightening in appearance towards the margins of the ellipses. Thermal Emission Imaging System (THEMIS) images suggest the haloes are dark particulate deposits. These deposits bury impact craters to a depth of less than a few decimetres. We argue that the elliptical haloes may be mineral precipitates and/or particulate deposits from ballistic volcanic eruptions that have been disrupted by the wind. They are likely be extremely young because <1m thick, low-albedo sedimentary deposits elsewhere on Mars have been observed to disappear in a few tens of years due to deposition of high-albedo dust.

  17. Sylvian Fissure Dermoid Cyst - A Rare case

    PubMed Central

    Anand, Deepak; Soin, Divya; Garg, Ravinder

    2014-01-01

    Intracranial dermoid cysts are rare tumours which usually occur in the midline. Sylvian fissure is a very unusual site for this lesion. This case presents a patient with unruptured dermoid cyst in the left sylvian fissure who was operated successfully without any residual deficit. PMID:25386502

  18. Fissure near Cerberus Fossae with Tectonic Morphologies

    NASA Image and Video Library

    2014-01-15

    The linearity of the volcanic vent shown in this image observed by NASA Mars Reconnaissance Orbiter, in conjunction with evidence of lava flow from the vent, suggests control by combined volcano-tectonic processes.

  19. Tooth bleaching and pit and fissure stain.

    PubMed

    Falconer, David Scott; Hamilton, James C; Stoffers, Kenneth W; Gregory, William A

    2008-04-01

    To investigate if tooth whitening had any effect on the shade of occlusal pit and fissure stains and whether reservoirs in bleaching trays affected bleaching of occlusal pit and fissure stains. 96 extracted molars were randomly divided into three paired groups for whitening using a 10% carbamide peroxide solution (Opalescence) or a 22% carbamide peroxide solution (Nite White Excel 3), or tap water for a control. One of each pair utilized reservoirs in their custom bleaching trays. Three dentists evaluated the shade of a specified occlusal area of pit and fissure stain twice before bleaching and twice after bleaching. Pit and fissure stain showed significant lightening of shade for either of the bleaching systems (P < 0.0005) but not the control (P = 0.816). There was no significant difference in pit and fissure stain shade lightening following treatment between those groups utilizing reservoirs in the custom trays and those without reservoirs (P = 0.658).

  20. Battery Vent Mechanism And Method

    DOEpatents

    Ching, Larry K. W.

    2000-02-15

    Disclosed herein is a venting mechanism for a battery. The venting mechanism includes a battery vent structure which is located on the battery cover and may be integrally formed therewith. The venting mechanism includes an opening extending through the battery cover such that the opening communicates with a plurality of battery cells located within the battery case. The venting mechanism also includes a vent manifold which attaches to the battery vent structure. The vent manifold includes a first opening which communicates with the battery vent structure opening and second and third openings which allow the vent manifold to be connected to two separate conduits. In this manner, a plurality of batteries may be interconnected for venting purposes, thus eliminating the need to provide separate vent lines for each battery. The vent manifold may be attached to the battery vent structure by a spin-welding technique. To facilitate this technique, the vent manifold may be provided with a flange portion which fits into a corresponding groove portion on the battery vent structure. The vent manifold includes an internal chamber which is large enough to completely house a conventional battery flame arrester and overpressure safety valve. In this manner, the vent manifold, when installed, lessens the likelihood of tampering with the flame arrester and safety valve.

  1. Battery venting system and method

    DOEpatents

    Casale, Thomas J.; Ching, Larry K. W.; Baer, Jose T.; Swan, David H.

    1999-01-05

    Disclosed herein is a venting mechanism for a battery. The venting mechanism includes a battery vent structure which is located on the battery cover and may be integrally formed therewith. The venting mechanism includes an opening extending through the battery cover such that the opening communicates with a plurality of battery cells located within the battery case. The venting mechanism also includes a vent manifold which attaches to the battery vent structure. The vent manifold includes a first opening which communicates with the battery vent structure opening and second and third openings which allow the vent manifold to be connected to two separate conduits. In this manner, a plurality of batteries may be interconnected for venting purposes, thus eliminating the need to provide separate vent lines for each battery. The vent manifold may be attached to the battery vent structure by a spin-welding technique. To facilitate this technique, the vent manifold may be provided with a flange portion which fits into a corresponding groove portion on the battery vent structure. The vent manifold includes an internal chamber which is large enough to completely house a conventional battery flame arrester and overpressure safety valve. In this manner, the vent manifold, when installed, lessens the likelihood of tampering with the flame arrester and safety valve.

  2. Battery venting system and method

    DOEpatents

    Casale, T.J.; Ching, L.K.W.; Baer, J.T.; Swan, D.H.

    1999-01-05

    Disclosed herein is a venting mechanism for a battery. The venting mechanism includes a battery vent structure which is located on the battery cover and may be integrally formed therewith. The venting mechanism includes an opening extending through the battery cover such that the opening communicates with a plurality of battery cells located within the battery case. The venting mechanism also includes a vent manifold which attaches to the battery vent structure. The vent manifold includes a first opening which communicates with the battery vent structure opening and second and third openings which allow the vent manifold to be connected to two separate conduits. In this manner, a plurality of batteries may be interconnected for venting purposes, thus eliminating the need to provide separate vent lines for each battery. The vent manifold may be attached to the battery vent structure by a spin-welding technique. To facilitate this technique, the vent manifold may be provided with a flange portion which fits into a corresponding groove portion on the battery vent structure. The vent manifold includes an internal chamber which is large enough to completely house a conventional battery flame arrester and overpressure safety valve. In this manner, the vent manifold, when installed, lessens the likelihood of tampering with the flame arrester and safety valve. 8 figs.

  3. Geometry of the September 1971 eruptive fissure at Kilauea volcano, Hawaii

    USGS Publications Warehouse

    Dvorak, J.J.

    1990-01-01

    A three-dimensional model has been used to estimate the location and dimensions of the eruptive fissure for the 24-29 September 1971 eruption along the southwest rift zone of Kilauea volcano, Hawaii. The model is an inclined rectangular sheet embedded in an elastic half-space with constant displacement on the plane of the sheet. The set of "best" model parameters suggests that the sheet is vertical, extends from a depth of about 2 km to the surface, and has a length of about 14 km. Because this sheet intersects the surface where eruptive vents and extensive ground cracking formed during the eruption, this sheet probably represents the conduit for erupted lava. The amount of displacement perpendicular to the sheet is about 1.9 m, in the middle range of values measured for the amount of opening across the September 1971 eruptive fissure. The thickness of the eruptive fissure associated with the January 1983 east rift zone eruption was determined in an earlier paper to be 3.6 m, about twice the thickness determined here for the September 1971 eruption. Because the lengths (12 km for 1983 and 14 km for 1971) and heights (about 2 km) of the sheet models derived for the January 1983 and September 1971 rift zone eruptions are nearly identical, the greater thickness for the January 1983 eruptive fissure implies that the magma pressure was about a factor of two greater to form the January 1983 eruptive fissure. Because the September 1971 and January 1983 eruptive fissures extent to depths of only a few kilometers, the region of greatest compressive stress produced along the volcano's flank by either of these eruptive fissures would also be within a few kilometers of the surface. Previous work has shown that rift eruptions and intrusions contribute to the buildup of compressive stress along Kilauea's south flank and that this buildup is released by increased seismicity along the south flank. Because south flank earthquakes occur at significantly greater depths, i.e., from 5

  4. Geometry of the September 1971 eruptive fissure at Kilauea volcano, Hawaii

    NASA Astrophysics Data System (ADS)

    Dvorak, John J.

    1990-09-01

    A three-dimensional model has been used to estimate the location and dimensions of the eruptive fissure for the 24 29 September 1971 eruption along the southwest rift zone of Kilauea volcano, Hawaii. The model is an inclined rectangular sheet embedded in an elastic half-space with constant displacement on the plane of the sheet. The set of “best” model parameters suggests that the sheet is vertical, extends from a depth of about 2 km to the surface, and has a length of about 14 km. Because this sheet intersects the surface where eruptive vents and extensive ground cracking formed during the eruption, this sheet probably represents the conduit for erupted lava. The amount of displacement perpendicular to the sheet is about 1.9 m, in the middle range of values measured for the amount of opening across the September 1971 eruptive fissure. The thickness of the eruptive fissure associated with the January 1983 east rift zone eruption was determined in an earlier paper to be 3.6 m, about twice the thickness determined here for the September 1971 eruption. Because the lengths (12 km for 1983 and 14 km for 1971) and heights (about 2 km) of the sheet models derived for the January 1983 and September 1971 rift zone eruptions are nearly identical, the greater thickness for the January 1983 eruptive fissure implies that the magma pressure was about a factor of two greater to form the January 1983 eruptive fissure. Because the September 1971 and January 1983 eruptive fissures extent to depths of only a few kilometers, the region of greatest compressive stress produced along the volcano's flank by either of these eruptive fissures would also be within a few kilometers of the surface. Previous work has shown that rift eruptions and intrusions contribute to the buildup of compressive stress along Kilauea's south flank and that this buildup is released by increased seismicity along the south flank. Because south flank earthquakes occur at significantly greater depths, i

  5. A robotic approach to mapping post-eruptive volcanic fissure conduits

    NASA Astrophysics Data System (ADS)

    Parcheta, Carolyn E.; Pavlov, Catherine A.; Wiltsie, Nicholas; Carpenter, Kalind C.; Nash, Jeremy; Parness, Aaron; Mitchell, Karl L.

    2016-06-01

    VolcanoBot was developed to map volcanic vents and their underlying conduit systems, which are rarely preserved and generally inaccessible to human exploration. It uses a PrimeSense Carmine 1.09 sensor for mapping and carries an IR temperature sensor, analog distance sensor, and an inertial measurement unit (IMU) inside a protective shell. The first field test succeeded in collecting valuable scientific data but revealed several needed improvements, including more rugged cable connections and mechanical couplers, increased ground clearance, and higher-torque motors for uphill mobility. The second field test significantly improved on all of these aspects but it traded electrical ruggedness for reduced data collection speed. Data collected by the VolcanoBots, while intermittent, yield the first insights into the cm-scale geometry of volcanic fissures at depths of up to 25 m. VolcanoBot was deployed at the 1969 Mauna Ulu fissure system on Kīlauea volcano in Hawai'i. It collected first-of-its-kind data from inside the fissure system. We hypothesized that 1) fissure sinuosity should decrease with depth, 2) irregularity should be persistent with depth, 3) any blockages in the conduit should occur at the narrowest points, and 4) the fissure should narrow with depth until it is too narrow for VolcanoBot to pass or is plugged with solidified lava. Our field campaigns did not span enough lateral or vertical area to test sinuosity. The preliminary data indicate that 1) there were many irregularities along fissures at depth, 2) blockages occurred, but not at obviously narrow locations, and 3) the conduit width remained a consistent 0.4-0.5 m for most of the upper 10 m that we analyzed.

  6. Payload bay atmospheric vent airflow testing at the Vibration and Acoustic Test Facility

    NASA Technical Reports Server (NTRS)

    Johnston, James D., Jr.

    1988-01-01

    Several concerns related to venting the Space Shuttle Orbiter payload bay during launch led to laboratory experiments with a flight-type vent box installed in the wall of a subsonic wind tunnel. This report describes the test setups and procedures used to acquire data for characterization of airflow through the vent box and acoustic tones radiated from the vent-box cavity. A flexible boundary-layer spoiler which reduced the vent-tone amplitude is described.

  7. Anorectal conditions: anal fissure and anorectal fistula.

    PubMed

    Fox, Audralan; Tietze, Pamela H; Ramakrishnan, Kalyanakrishnan

    2014-04-01

    Anal fissures are linear splits in the anal mucosa. Acute fissures typically resolve within a few weeks; chronic fissures persist longer than 8 to 12 weeks. Most fissures are posterior and midline and are related to constipation or anal trauma. Painful defecation and rectal bleeding are common symptoms. The diagnosis typically is clinical. High-fiber diet, stool softeners, and medicated ointments relieve symptoms and speed healing of acute fissures but offer limited benefit in chronic fissures. Lateral internal sphincterotomy is the surgical management of choice for chronic and refractory acute fissures. Anorectal fistula is an abnormal tract connecting the anorectal mucosa to the exterior skin. Fistulas typically develop after rupture or drainage of a perianal abscess. Fistulas are classified as simple or complex; low or high; and intersphincteric, transsphincteric, suprasphincteric, or extrasphincteric. Inspection of the perianal area identifies the skin opening, and anoscopy visualizes internal openings. The goal of management is to obliterate the tract and openings with negligible sphincter disruption to minimize incontinence. Fistulotomy is effective for simple fistulas; patients with complex fistulas may require fistulectomy. Other procedures that are used include injection of fibrin glue or insertion of a bioprosthetic plug into the fistula opening.

  8. Overview of the precursors and dynamics of the 2012-13 basaltic fissure eruption of Tolbachik Volcano, Kamchatka, Russia

    NASA Astrophysics Data System (ADS)

    Belousov, Alexander; Belousova, Marina; Edwards, Benjamin; Volynets, Anna; Melnikov, Dmitry

    2015-12-01

    We present a broad overview of the 2012-13 flank fissure eruption of Plosky Tolbachik Volcano in the central Kamchatka Peninsula. The eruption lasted more than nine months and produced approximately 0.55 km3 DRE (volume recalculated to a density of 2.8 g/cm3) of basaltic trachyandesite magma. The 2012-13 eruption of Tolbachik is one of the most voluminous historical eruptions of mafic magma at subduction related volcanoes globally, and it is the second largest at Kamchatka. The eruption was preceded by five months of elevated seismicity and ground inflation, both of which peaked a day before the eruption commenced on 27 November 2012. The batch of high-Al magma ascended from depths of 5-10 km; its apical part contained 54-55 wt.% SiO2, and the main body 52-53 wt.% SiO2. The eruption started by the opening of a 6 km-long radial fissure on the southwestern slope of the volcano that fed multi-vent phreatomagmatic and magmatic explosive activity, as well as intensive effusion of lava with an initial discharge of > 440 m3/s. After 10 days the eruption continued only at the lower part of the fissure, where explosive and effusive activity of Hawaiian-Strombolian type occurred from a lava pond in the crater of the main growing scoria cone. The discharge rate for the nine month long, effusion-dominated eruption gradually declined from 140 to 18 m3/s and formed a compound lava field with a total area of 36 km2; the effusive activity evolved from high-discharge channel-fed 'a'a lavas to dominantly low-discharge tube-fed pahoehoe lavas. On 23 August, the effusion of lava ceased and the intra-crater lava pond drained. Weak Strombolian-type explosions continued for several more days on the crater bottom until the end of the eruption around 5 September 2013. Based on a broad array of new data collected during this eruption, we develop a model for the magma storage and transport system of Plosky Tolbachik that links the storage zones of the two main genetically related magma types

  9. Fissure distribution at Mauna Loa (Hawaii) as an example to understand shallow magma transfer at volcanoes

    NASA Astrophysics Data System (ADS)

    La Marra, Daniele; Acocella, Valerio; Trusdell, Frank

    2016-04-01

    Mauna Loa (Hawaii) is the largest active shield volcano on the Island of Hawai'i, covering more than half of it and rising to 4,169 meters above sea level. The volcano hosts the Moku'aweoweo summit caldera, from which two elongated rift zones depart: the Northeast Rift Zone (NERZ) and the Southwest Rift Zone (SWRZ). Most of Mauna Loa's eruptions begin with lava fountains from a series of fissure vents in the summit region and then often migrate to vents down either rift zone. Mauna Loa volcano shows a distinctive feature, being characterized by minor radial eruptive fissures (not related to the two main rifts) on the NW flank only. This study tries to explain such a selective distribution of vents, and thus of shallow magma transfer. To this aim, we run numerical models with different amount of opening of the two rift zones of Mauna Loa, as well as different amount of slip on its SE flank. Our results suggest that the selective occurrence of the radial fissures may be explained by the competition between two processes: a) rift intrusion (especially along the NERZ), promoting the development of radial dikes along the NW flank; b) flank slip, inhibiting the development of the radial dikes on the SE flank. The opening of the two non-parallel main rift zones of Mauna Loa promotes the local extension necessary to develop the radial dikes on the NW flank. A general model for the development of a third branch of radial rift, which may be also applied to Mt. Etna and some volcanoes on the Canary Islands, is proposed.

  10. [Botulinum toxin and chronic anal fissure].

    PubMed

    Daniel, Fady; de Parades, Vincent; Siproudhis, Laurent; Atienza, Patrick

    2006-05-01

    Lateral internal sphincterotomy is widely used in the treatment of chronic anal fissure. However, it is associated with a high rate of irreversible incontinence. For this reason the botulinum toxin has become a medical means of reversible sphincterotomy. Indeed, this neurotoxin induces relaxation of the smooth internal anal sphincter lasting one to three months after one injection. We reviewed the published studies about the use of this technique in the management of chronic anal fissure. Healing occurred in more than 70% of fissures without irreversible incontinence. Although further studies are needed to determine the best modalities of administration, especially due to the remaining significant recurrence rate, this toxin may be a valuable treatment for chronic anal fissure in the future.

  11. Multiple I-Type Lysozymes in the Hydrothermal Vent Mussel Bathymodiolus azoricus and Their Role in Symbiotic Plasticity.

    PubMed

    Detree, Camille; Chabenat, Apolline; Lallier, François H; Satoh, Nori; Shoguchi, Eiichi; Tanguy, Arnaud; Mary, Jean

    2016-01-01

    The aim of this study was first to identify lysozymes paralogs in the deep sea mussel Bathymodiolus azoricus then to measure their relative expression or activity in different tissue or conditions. B. azoricus is a bivalve that lives close to hydrothermal chimney in the Mid-Atlantic Ridge (MAR). They harbour in specialized gill cells two types of endosymbiont (gram-bacteria): sulphide oxidizing bacteria (SOX) and methanotrophic bacteria (MOX). This association is thought to be ruled by specific mechanism or actors of regulation to deal with the presence of symbiont but these mechanisms are still poorly understood. Here, we focused on the implication of lysozyme, a bactericidal enzyme, in this endosymbiosis. The relative expression of Ba-lysozymes paralogs and the global anti-microbial activity, were measured in natural population (Lucky Strike--1700 m, Mid-Atlantic Ridge), and in in situ experimental conditions. B. azoricus individuals were moved away from the hydrothermal fluid to induce a loss of symbiont. Then after 6 days some mussels were brought back to the mussel bed to induce a re-acquisition of symbiotic bacteria. Results show the presence of 6 paralogs in B. azoricus. In absence of symbionts, 3 paralogs are up-regulated while others are not differentially expressed. Moreover the global activity of lysozyme is increasing with the loss of symbiont. All together these results suggest that lysozyme may play a crucial role in symbiont regulation.

  12. Multiple I-Type Lysozymes in the Hydrothermal Vent Mussel Bathymodiolus azoricus and Their Role in Symbiotic Plasticity

    PubMed Central

    Detree, Camille; Chabenat, Apolline; Lallier, François H.; Satoh, Nori; Shoguchi, Eiichi; Tanguy, Arnaud; Mary, Jean

    2016-01-01

    The aim of this study was first to identify lysozymes paralogs in the deep sea mussel Bathymodiolus azoricus then to measure their relative expression or activity in different tissue or conditions. B. azoricus is a bivalve that lives close to hydrothermal chimney in the Mid-Atlantic Ridge (MAR). They harbour in specialized gill cells two types of endosymbiont (gram—bacteria): sulphide oxidizing bacteria (SOX) and methanotrophic bacteria (MOX). This association is thought to be ruled by specific mechanism or actors of regulation to deal with the presence of symbiont but these mechanisms are still poorly understood. Here, we focused on the implication of lysozyme, a bactericidal enzyme, in this endosymbiosis. The relative expression of Ba-lysozymes paralogs and the global anti-microbial activity, were measured in natural population (Lucky Strike -1700m, Mid-Atlantic Ridge), and in in situ experimental conditions. B. azoricus individuals were moved away from the hydrothermal fluid to induce a loss of symbiont. Then after 6 days some mussels were brought back to the mussel bed to induce a re-acquisition of symbiotic bacteria. Results show the presence of 6 paralogs in B. azoricus. In absence of symbionts, 3 paralogs are up-regulated while others are not differentially expressed. Moreover the global activity of lysozyme is increasing with the loss of symbiont. All together these results suggest that lysozyme may play a crucial role in symbiont regulation. PMID:26882089

  13. Modeling plaque fissuring and dissection during balloon angioplasty intervention.

    PubMed

    Gasser, T Christian; Holzapfel, Gerhard A

    2007-05-01

    Balloon angioplasty intervention is traumatic to arterial tissue. Fracture mechanisms such as plaque fissuring and/or dissection occur and constitute major contributions to the lumen enlargement. However, these types of mechanically-based traumatization of arterial tissue are also contributing factors to both acute procedural complications and chronic restenosis of the treatment site. We propose physical and finite element models, which are generally useable to trace fissuring and/or dissection in atherosclerotic plaques during balloon angioplasty interventions. The arterial wall is described as an anisotropic, heterogeneous, highly deformable, nearly incompressible body, whereas tissue failure is captured by a strong discontinuity kinematics and a novel cohesive zone model. The numerical implementation is based on the partition of unity finite element method and the interface element method. The later is used to link together meshes of the different tissue components. The balloon angioplasty-based failure mechanisms are numerically studied in 3D by means of an atherosclerotic-prone human external iliac artery, with a type V lesion. Image-based 3D geometry is generated and tissue-specific material properties are considered. Numerical results show that in a primary phase the plaque fissures at both shoulders of the fibrous cap and stops at the lamina elastica interna. In a secondary phase, local dissections between the intima and the media develop at the fibrous cap location with the smallest thickness. The predicted results indicate that plaque fissuring and dissection cause localized mechanical trauma, but prevent the main portion of the stenosis from high stress, and hence from continuous tissue damage.

  14. Global relationships between volcanic vents and fractures radial to large impact basins on Mars

    NASA Technical Reports Server (NTRS)

    Schneid, Byron D.; Greeley, Ronald

    1991-01-01

    The relation of volcanic vents on Mars to impact basins has been previously studied. It has been asserted that the concentric fractures around impact basins extend into the crust and might localize some features, including volcanoes. Herein, the possibility is assessed of radial fractures inferred to be associated with impact basins as an additional control on the location of volcanoes on Mars. Geologic mapping at 1:2 million scale enabled 250 central vents and fissure vents to be identified. Pattern of vent distribution superimposed on a globe show that most are located on three distinct circles. In addition, there are two more possible great circles which may be superimposed onto the Martian globe. These five Martian circles are briefly examined for their geological relationship to volcanoes.

  15. Pit and fissure sealants or fluoride varnishes?

    PubMed

    Paglia, L

    2016-09-01

    Despite the general advances in dental care, dental caries is still a global health problem affecting many children. Occlusal surfaces of first permanent molars are the most susceptible sites in the developing permanent dentition. Dentists should use sealants or fluoride varnish - as well as other means - to limit the onset of tooth decay. Application of sealants is a recommended procedure to prevent or control caries. Sealing occlusal surfaces of newly erupted permanent molars in children and teenagers delays caries onset up to 48 months compared with unsealed teeth. However longer follow-ups shows a reduction of the preventive effect [Tikhonova et al., 2015]. A review of 2013 pointed out how sealants are effective in high risk children, however information about the benefits of sealing in other conditions is still scant [Ahovuo-Saloranta et al., 2013]. Fluoride varnishes are frequently used to prevent early childhood caries and reduce caries increment in very young children [Weintraub et al., 2006] and in the most vulnerable populations, where the prevalence of caries is higher and specialist visits are occasional [Chu et al., 2010]. Many studies have reported the effectiveness of different types and forms of fluoride agents in preventing dental caries among children and adolescents [Divaris et al., 2013]. A review clarifies that professional application of a 5% sodium fluoride varnish leads to remineralisation of early enamel caries in children. Solutions of 38% silver diamine fluoride are effective in arresting active dentine caries [Gao et al., 2016]. The last systematic review [Ahovuo-Saloranta et al., 2016], comparing pit and fissure sealants with fluoride varnishes explains that the pooled estimate slightly favours resin sealants over fluoride varnishes at two years. At four and nine years, the only comparative study (with high drop-out rates) found more caries on fluoride-varnished occlusal surfaces than on resin-sealed surfaces. There is evidence

  16. Construction of an Ice-Confined Basaltic Fissure Complex: Sveifluháls, SW Iceland

    NASA Astrophysics Data System (ADS)

    Mercurio, E. C.; Skilling, I. P.

    2010-12-01

    The study of ice-confined volcanoes is important for understanding sub-ice volcanic activity and its effects on overlying ice in the past and present. While we have good understanding of the processes and products of single-vent ice-confined eruptions, very little is understood about the processes and products of multi-vent, multi-fissure, ice-confined eruption complexes (i.e., “tindar”) like Sveifluháls, even though more than 1000 of these structures exist in Iceland. At Sveifluháls (elev. 400 m ASL), the DRE volume is a minimum of 2.9 cubic km. The complex is approximately 21 km long, 1.5 km wide, 250 m thick, and comprised of about 60 discrete fissure segments oriented NE-SW and ranging from 0.2 km to 1 km in length. Average vent spacing of individual eruptive centers is approximately 0.7 km, and individual fissure segments are generally 0.1 to 0.5 km apart. The gross structure of the ridge comprises a 60 m sequence of basal lavas emplaced into subglacial water, overlain by about 100 m of mostly non-bedded and water-deposited phreatomagmatic lapilli tuff, and capped by a narrower zone of bedded phreatomagmatic lapilli tuff (about 80 m thick). There is no evidence of any significant time gap from one vent to another, and fissure segments similarly lack evidence of an eruptive lag time. XRF data show very similar major element compositions along the complex, further indicating that the eruptions were fed from the same magma reservoir over a short period. Intrusions that propagated into unconsolidated wet sediment played an important role in the generation of intrusive pillows and coarse pillow breccia (peperites), and locally fed extrusive pillow lavas on subaqueous paleo-slopes of tuff cones. Such intrusive pillows should clearly be avoided when selecting samples for volatile analysis and former ice thickness interpretation. High-level dike emplacement is also one of the causes of failure of large bedded tephra blocks that slid down the ridge flanks and

  17. Coupled pulsing of lava fountains: Video monitoring reveals systematic height and velocity variations of adjacent vents

    NASA Astrophysics Data System (ADS)

    Witt, Tanja; Walter, Thomas R.

    2014-05-01

    Lava fountains are a common eruption form at basaltic volcanoes. Many of the lava fountains occur at fissure eruptions, associated with the alignment of active vents. We observed that the lava fountain pulses may occur in chorus at several adjacent vents, implying that activity at these vents is coupled. The mechanisms behind such a coupling of adjacent lava fountains and the underlying connection between the different craters are not fully understood, however. Here we employ video images to measure the height, width and velocity of the ejecta leaving the vent. With a Sobel edge-detection algorithm, our aim is to measure the height of the different fountains occurring along fissure eruptions. Video data acquired from Puu'oo (Hawaii) and from Eyjafjallajökull (Iceland) are showing major similarities in fountaining behavior. Based on the fountain activity times series we estimate the sign and degree of correlation of the different vents. We find that the height and velocity of adjacent lava fountains are often in chorus. The velocity is calculated by a correlation in the Fourier space of contiguous images. We observed that episodically and sporadically the correlation regime can change. Despite these changes, both the frequency of the lava pulses and the eruption and rest time between the pulses remain similar for adjacent lava fountains, implying, a controlling process in the magma feeder system itself. We interpret the initial vertical velocity at the vent to be proportional to the extent of bubbles, and layers of bubbles rising. Lateral migration of fountains and their dynamics, in turn, is associated to lateral magma and gas flow or inclined layers of bubbles developing along the fissure at depth. Systematic recording and analysis of video data from different volcanoes hence result in a better understanding of the mechanisms of parallel and non-parallel lava fountain pulses.

  18. Identifying the best therapy for chronic anal fissure

    PubMed Central

    Madalinski, Mariusz H

    2011-01-01

    Chronic anal fissure (CAF) is a painful tear or crack which occurs in the anoderm. The optimal algorithm of therapy for CAF is still debated. Lateral internal sphincterotomy (LIS) is a surgical treatment, considered as the ‘gold standard’ therapy for CAF. It relieves CAF symptoms with a high rate of healing. Chemical sphincterotomy (CS) with nitrates, calcium blockers or botulinum toxin (BTX) is safe, with the rapid relief of pain, mild side-effects and no risk of surgery or anesthesia, but is a statistically less effective therapy for CAF than LIS. This article considers if aggressive treatment should only be offered to patients who fail pharmacological sphincterotomy. Aspects of anal fissure etiology, epidemiology and pathophysiology are considered with their meaning for further management of CAF. A molecular model of chemical interdependence significant for the chemistry of CAF healing is examined. Its application may influence the development of optimal therapy for CAF. BTX is currently considered the most effective type of CS and discussion in this article scrutinizes this method specifically. Although the effectiveness of BTX vs. LIS has been discussed, the essential focus of the article concerns identifying the best therapy application for anal fissure. Elements are presented which may help us to predict CAF healing. They provide rationale for the expansion of the CAF therapy algorithm. Ethical and economic factors are also considered in brief. As long as the patient is willing to accept the potential risk of fecal incontinence, we have grounds for the ‘gold standard’ (LIS) as the first-line treatment for CAF. The author concludes that, when the diagnosis of the anal fissure is established, CS should be considered for both ethical and economic reasons. He is convinced that a greater understanding and recognition of benign anal disorders by the GP and a proactive involvement at the point of initial diagnosis would facilitate the consideration of CS at

  19. Boiling vapour-type fluids from the Nifonea vent field (New Hebrides Back-Arc, Vanuatu, SW Pacific): Geochemistry of an early-stage, post-eruptive hydrothermal system

    NASA Astrophysics Data System (ADS)

    Schmidt, Katja; Garbe-Schönberg, Dieter; Hannington, Mark D.; Anderson, Melissa O.; Bühring, Benjamin; Haase, Karsten; Haruel, Christy; Lupton, John; Koschinsky, Andrea

    2017-06-01

    In 2013, high-temperature vent fluids were sampled in the Nifonea vent field. This field is located within the caldera of a large shield-type volcano of the Vate Trough, a young extensional rift in the New Hebrides back-arc. Hydrothermal venting occurs as clear and black smoker fluids with temperatures up to 368 °C, the hottest temperatures measured so far in the western Pacific. The physico-chemical conditions place the fluids within the two-phase field of NaCl-H2O, and venting is dominated by vapour phase fluids with Cl concentrations as low as 25 mM. The fluid composition, which differs between the individual vent sites, is interpreted to reflect the specific geochemical fluid signature of a hydrothermal system in its initial, post-eruptive stage. The strong Cl depletion is accompanied by low alkali/Cl ratios compared to more evolved hydrothermal systems, and very high Fe/Cl ratios. The concentrations of REY (180 nM) and As (21 μM) in the most Cl-depleted fluid are among the highest reported so far for submarine hydrothermal fluids, whereas the inter-element REY fractionation is only minor. The fluid signature, which has been described here for the first time in a back-arc setting, is controlled by fast fluid passage through basaltic volcanic rocks, with extremely high water-rock ratios and only limited water-rock exchange, phase separation and segregation, and (at least) two-component fluid mixing. Metals and metalloids are unexpectedly mobile in the vapour phase fluids, and the strong enrichments of Fe, REY, and As highlight the metal transport capacity of low-salinity, low-density vapours at the specific physico-chemical conditions at Nifonea. One possible scenario is that the fluids boiled before the separated vapour phase continued to react with fresh glassy lavas. The mobilization of metals is likely to occur by leaching from fresh glass and grain boundaries and is supported by the high water/rock ratios. The enrichment of B and As is further controlled

  20. Thoracoscopic anterior ‘fissure first’ technique for left lung cancer with an incomplete fissure

    PubMed Central

    Samejima, Joji; Matsuura, Yosuke; Nakao, Masayuki; Uehara, Hirofumi; Nakagawa, Ken; Masuda, Munetaka; Okumura, Sakae

    2016-01-01

    Background Dealing with incomplete lung fissures during thoracoscopic surgery is difficult. Our objective was to evaluate the efficacy and safety of a thoracoscopic anterior ‘fissure first’ technique for dealing with incomplete left lung fissures. Methods One hundred and seventy patients underwent left upper lobectomy or left lower lobectomy between April 2008 and July 2014. Of these, 34 patients underwent surgery using a thoracoscopic anterior ‘fissure first’ technique for incomplete fissures (group A) and 136 underwent surgery using a conventional thoracoscopic method for unfused fissures (group B). A four-port complete thoracoscopic approach was used in all patients. After completion of the fissure, hilar lymphadenectomy was performed in the conventional manner. Results There were no significant differences between the two groups in operating time, blood loss, or duration of chest tube drainage. Patients in group A required more staple cartridges than those in group B (mean number of cartridges, 2.4 vs. 1.1; P<0.01). The two groups did not significantly differ with regard to the prevalence of air leaks (12% vs. 4%; P=0.11), either prolonged or delayed. Conclusions We found that a thoracoscopic anterior ‘fissure first’ technique for left lung cancer with an incomplete fissure enabled hilar lymphadenectomy to be performed in the conventional manner without any increase in the prevalence of air leaks, operating time, or duration of chest tube drainage. This technique should be considered for use in left upper lobectomy or left lower lobectomy in patients with an incomplete fissure. PMID:28066589

  1. Coil spring venting arrangement

    DOEpatents

    McCugh, R.M.

    1975-10-21

    A simple venting device for trapped gas pockets in hydraulic systems is inserted through a small access passages, operated remotely, and removed completely. The device comprises a small diameter, closely wound coil spring which is pushed through a guide temporarily inserted in the access passage. The guide has a central passageway which directs the coil spring radially upward into the pocket, so that, with the guide properly positioned for depth and properly oriented, the coil spring can be pushed up into the top of the pocket to vent it. By positioning a seal around the free end of the guide, the spring and guide are removed and the passage is sealed.

  2. Robust pulmonary lobe segmentation against incomplete fissures

    NASA Astrophysics Data System (ADS)

    Gu, Suicheng; Zheng, Qingfeng; Siegfried, Jill; Pu, Jiantao

    2012-03-01

    As important anatomical landmarks of the human lung, accurate lobe segmentation may be useful for characterizing specific lung diseases (e.g., inflammatory, granulomatous, and neoplastic diseases). A number of investigations showed that pulmonary fissures were often incomplete in image depiction, thereby leading to the computerized identification of individual lobes a challenging task. Our purpose is to develop a fully automated algorithm for accurate identification of individual lobes regardless of the integrity of pulmonary fissures. The underlying idea of the developed lobe segmentation scheme is to use piecewise planes to approximate the detected fissures. After a rotation and a global smoothing, a number of small planes were fitted using local fissures points. The local surfaces are finally combined for lobe segmentation using a quadratic B-spline weighting strategy to assure that the segmentation is smooth. The performance of the developed scheme was assessed by comparing with a manually created reference standard on a dataset of 30 lung CT examinations. These examinations covered a number of lung diseases and were selected from a large chronic obstructive pulmonary disease (COPD) dataset. The results indicate that our scheme of lobe segmentation is efficient and accurate against incomplete fissures.

  3. 24 CFR 3280.611 - Vents and venting.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... air circulation shall be ensured throughout all parts of the drainage system by means of vents...) Materials—(1) Pipe. Vent piping shall be standard weight steel, wrought iron, brass, copper tube DWV, listed... for all changes in direction or size and where pipes are joined. The material and design of vent...

  4. 24 CFR 3280.611 - Vents and venting.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... air circulation shall be ensured throughout all parts of the drainage system by means of vents...) Materials—(1) Pipe. Vent piping shall be standard weight steel, wrought iron, brass, copper tube DWV, listed... for all changes in direction or size and where pipes are joined. The material and design of vent...

  5. Evaluation of Soil Venting Application

    EPA Pesticide Factsheets

    The ability of soil venting to inexpensively remove large amounts of volatile organic compounds (VOCs) from contaminated soils is well established. However, the time required using venting to remediate soils to low contaminant levels often required by..

  6. Earth fissures and localized differential subsidence.

    USGS Publications Warehouse

    Holzer, Thomas L.; Pampeyan, Earl H.

    1981-01-01

    Long linear tension cracks associated with declining groundwater levels at four sites in subsiding areas in south-central Arizona, Fremont Valley, California, and Las Vegas Valley, Nevada, occur near points of maximum convex-upward curvature in subsidence profiles oriented perpendicular to the cracks. Profiles are based on repeated precise vertical control surveys of lines of closely spaced bench marks. Association of these fissures with zones of localized differential subsidence indicates that linear earth fissures are caused by horizontal tensile strains probably resulting from localized differential compaction. Horizontal tensile strains across the fissures at the point of maximum convex-upward curvature, ranging from approximately 100 to 700 microstrains (0.01 to 0.07% per year), were indicated based on measurements with a tape or electronic distance meter.

  7. Space LOX vent system

    NASA Technical Reports Server (NTRS)

    Stark, J. A.

    1972-01-01

    The research of the program to design and build a prototype vent system capable of exhausting only vapor to space from an all liquid or two-phase mixture of oxygen, while operating under low or zero-gravity conditions is reported. Work performed during the detail design phase of the program was concerned with the finalization of vent system performance, development of component specifications, solicitation of vendor bids, selection of components and overall system package design. The compact system preliminary design defined for the comparisons was reviewed in light of a desirability to demonstrate complete tank mixing at one-g. Also, performance of the system at low-g conditions with a full tank and maximum temperature stratification or maximum pressure rise between vent cycles was investigated. It was found that under these extreme conditions, not previously considered, that use of a larger pump mixer than previously defined would be desirable. In addition, to simplify ground testing with only a small weight penalty, the exchanger vent pressure was increased from 5 psia to 22 psia nominal. This resulted in less than a 0.2% increase in system weight.

  8. Measure Guideline: Passive Vents

    SciTech Connect

    Berger, David; Neri, Robin

    2016-02-05

    This document addresses the use of passive vents as a source of outdoor air in multifamily buildings. The challenges associated with implementing passive vents and the factors affecting performance are outlined. A comprehensive design methodology and quantified performance metrics are provided. Two hypothetical design examples are provided to illustrate the process. This document is intended to be useful to designers, decision-makers, and contractors implementing passive ventilation strategies. It is also intended to be a resource for those responsible for setting high-performance building program requirements, especially pertaining to ventilation and outdoor air. To ensure good indoor air quality, a dedicated source of outdoor air is an integral part of high-performance buildings. Presently, there is a lack of guidance pertaining to the design and installation of passive vents, resulting in poor system performance. This report details the criteria necessary for designing, constructing, and testing passive vent systems to enable them to provide consistent and reliable levels of ventilation air from outdoors.

  9. Vent Relief Valve Test

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Shown is the disassembly, examination, refurbishment and testing of the LH2 ( liquid hydrogen) and LOX (liquid oxygen) vent and relief valves for the S-IVB-211 engine stage in support of the Constellation/Ares project. This image is extracted from high definition video and is the highest resolution available.

  10. A One-Year Evaluation of a Free Fissure Sealant Program

    PubMed Central

    M, Bakhtiar; N, Azadi; A, Golkari

    2016-01-01

    Statement of Problem: Pit and fissure sealant therapy has been approved as an effective measure in the prevention of occlusal dental caries. Resin based materials are the most common materials used worldwide. A variety of resin based fissure sealants are produced and used. Most of them have been presented with ideal results in research environment. However, their effectiveness in the real life, especially in a mass application program such as Iran’s oral health reform plan is not clear. Objectives: To evaluate the longevity of different fissure sealant applied in Iran’s oral health reform plan in Fars Province (south of Iran) after one year. Materials and Methods: Seven counties were selected. One hundred 6- to 8-year-old school children who had undergone fissure sealant therapy in spring 2015 were randomly selected from each county. Their first molars were examined to evaluate the status of the fissure sealants which were applied one year ago. Data on the type/brand of fissure sealant materials, type and experience of clinicians who applied them, existence of a chair-side assistant, and whether the children were caries-free at the time of fissure sealant application were collected from the existing reports. Results: Data of 1974 teeth from 598 children were used for the final analysis. The effects of type/brand of the material was significant on the final results and remained significant (p < 0.001) after adjustments for the level of fluoride, urban/rural area, upper/lower jaw, type of clinician who applied the sealant, existence of a chair-side assistant, and child’s gender, age, and being caries-free. Conclusions: Many factors affect the success rate of a fissure sealant therapy program. The type/brand of the material remained significantly related to the success rate of the fissure sealant even after adjustments for other influencing factors. In this study, ClinproTM Sealant (3M/ESPE, USA) showed better longevity after one year of application. PMID

  11. On Small Disturbance Ascent Vent Behavior

    NASA Technical Reports Server (NTRS)

    Woronowicz, Michael

    2015-01-01

    As a spacecraft undergoes ascent in a launch vehicle, its ambient pressure environment transitions from one atmosphere to high vacuum in a matter of a few minutes. Venting of internal cavities is necessary to prevent the buildup of pressure differentials across cavity walls. These pressure differentials are often restricted to low levels to prevent violation of container integrity. Such vents usually consist of fixed orifices, ducts, or combinations of both. Duct conductance behavior is fundamentally different from that for orifices in pressure driven flows governing the launch vehicle ascent depressurization environment. Duct conductance is governed by the average pressure across its length, while orifice conductance is dictated by a pressure ratio. Hence, one cannot define a valid equivalent orifice for a given duct across a range of pressure levels. This presentation discusses development of expressions for these two types of vent elements in the limit of small pressure differentials, explores conditions for their validity, and compares their features regarding ascent depressurization performance.

  12. Instrumentation and measurement of airflow and temperature in attics fitted with ridge and soffit vents

    SciTech Connect

    Romero, M.I.; Brenner, R.J.

    1998-12-31

    This study established a research facility where airflow velocities, temperature, and differential pressures could be measured at the ridge of an attic. Following the construction of a test building, sensors were constructed, calibrated, and installed inside the attic. Paired tests were performed for three different ridge vent treatments; two were rolled type vents and one was a baffled vent. When both attics were fitted with the same ridge vent, the airspeed and differential pressure profiles at the ridge were very similar for both attics, indicating that any observed differences in airspeed and differential pressure were caused by the ridge vent treatment used. The baffled vent and rolled vents were then installed on the ridge of the west and east attics, respectively. The data demonstrated that the baffled ridge vent provided a minimum of twice the ridge airspeed of the rolled vents, when all wind conditions were considered. On the day selected to study the direction of the airflows at the ridge, the baffled vent had airflow speeds at the ridge similar to the rolled vent without fabric backing. The baffled vent allowed air to come out of the attic through both sides of the ridge (negative differential pressures on both sides), while the rolled vent without fabric backing caused air to enter through the south side of the ridge and exit through the north side (positive differential pressure on the south side and negative differential pressure on the north), in effect short-circuiting the vent. The fabric-backed rolled vent allowed attic air to come out of the attic through both sides of the ridge, as did the baffled vent, but the airspeed was slower. The baffled vent was the one with the highest airspeed at the ridge and also had both sides of the vent under negative differential pressure, providing the most effective ventilation.

  13. Identification of the pleural fissures with computed tomography

    SciTech Connect

    Marks, B.W.; Kuhns, L.R.

    1982-04-01

    The pleural fissures can be identified as avascular planes within the pulmonary parenchyma on CT scans. A retrospective analysis of 23 consecutive scans was conducted to consider identification of fissures. On 21% of the axial images, a ''ground glass'' band was identified within the avascular plane, probably due to partial volume averaging of the pleural fissure with the adjacent lung. The pleural fissures could be identified in 84% of cases.

  14. Recent ground fissures in the Hetao basin, Inner Mongolia, China

    NASA Astrophysics Data System (ADS)

    He, Zhongtai; Ma, Baoqi; Long, Jianyu; Zhang, Hao; Liang, Kuan; Jiang, Dawei

    2017-10-01

    Ground fissures are a geological hazard with complex formation mechanisms. Increasing amounts of human activity have created more ground fissures, which can destroy buildings and threaten human security. Some ground fissures indicate potentially devastating earthquakes, so we must pay attention to these hazards. This paper documents recently discovered ground fissures in the Hetao basin. These ground fissures are located along the frontal margins of the terraces of the Sertengshan piedmont fault. These fissures are 600-1600 m long, 5-50 cm wide, and at most 1 m deep. These ground fissures emerged after 2010 and ruptured newly constructed roads and field ridges. The deep geodynamic mechanisms within this extensional environment, which is dominated by NE-SW principal compressive shear, involve N-S tensile stress, which has produced continuous subsidence in the Hetao basin and continuous activity along the Sertengshan piedmont fault since the late Quaternary. Trenches across the ground fissures reveal that the fissures are the latest manifestation of the activity of preexisting faults and are the result of creep-slip movement along the faults. The groundwater level in the Hetao basin has been dropping since the 1960s because of overexploitation, resulting in subsidence. When the tensile stress exceeds the ultimate tensile strength of the strata, the strata rupture along preexisting faults, producing ground fissures. Thus, the Sertengshan piedmont fault planes are the structural foundation of the ground fissures, and groundwater extraction induces the development of ground fissures.

  15. Fissural volcanism, polygenetic volcanic fields, and crustal thickness in the Payen Volcanic Complex on the central Andes foreland (Mendoza, Argentina)

    NASA Astrophysics Data System (ADS)

    Mazzarini, F.; Fornaciai, A.; Bistacchi, A.; Pasquarè, F. A.

    2008-09-01

    Shield volcanoes, caldera-bearing stratovolcanoes, and monogenetic cones compose the large fissural Payen Volcanic Complex, located in the Andes foreland between latitude 35°S and 38°S. The late Pliocene-Pleistocene and recent volcanic activity along E-W trending eruptive fissures produced basaltic lavas showing a within-plate geochemical signature. The spatial distribution of fractures and monogenetic vents is characterized by self-similar clustering with well defined power law distributions. Vents have average spacing of 1.27 km and fractal exponent D = 1.33 defined in the range 0.7-49.3 km. The fractal exponent of fractures is 1.62 in the range 1.5-48.1 km. The upper cutoffs of fractures and vent fractal distributions (about 48-49 km) scale to the crustal thickness in the area, as derived from geophysical data. This analysis determines fractured media (crust) thickness associated with basaltic retroarc eruptions. We propose that the Payen Volcanic Complex was and is still active under an E-W crustal shortening regime.

  16. Airbag vent valve and system

    NASA Technical Reports Server (NTRS)

    Peterson, Leslie D. (Inventor); Zimmermann, Richard E. (Inventor)

    2001-01-01

    An energy absorbing airbag system includes one or more vent valve assemblies for controlling the release of airbag inflation gases to maintain inflation gas pressure within an airbag at a substantially constant pressure during a ride-down of an energy absorbing event. Each vent valve assembly includes a cantilever spring that is flat in an unstressed condition and that has a free end portion. The cantilever spring is secured to an exterior surface of the airbag housing and flexed to cause the second free end portion of the cantilever spring to be pressed, with a preset force, against a vent port or a closure covering the vent port to seal the vent port until inflation gas pressure within the airbag reaches a preselected value determined by the preset force whereupon the free end portion of the cantilever spring is lifted from the vent port by the inflation gases within the airbag to vent the inflation gases from within the airbag. The resilience of the cantilever spring maintains a substantially constant pressure within the airbag during a ride-down portion of an energy absorbing event by causing the cantilever spring to vent gases through the vent port whenever the pressure of the inflation gases reaches the preselected value and by causing the cantilever spring to close the vent port whenever the pressure of the inflation gases falls below the preselected value.

  17. Staged venting of fuel cell system during rapid shutdown

    DOEpatents

    Keskula, Donald H.; Doan, Tien M.; Clingerman, Bruce J.

    2004-09-14

    A venting methodology and system for rapid shutdown of a fuel cell apparatus of the type used in a vehicle propulsion system. H.sub.2 and air flows to the fuel cell stack are slowly bypassed to the combustor upon receipt of a rapid shutdown command. The bypass occurs over a period of time (for example one to five seconds) using conveniently-sized bypass valves. Upon receipt of the rapid shutdown command, the anode inlet of the fuel cell stack is instantaneously vented to a remote vent to remove all H.sub.2 from the stack. Airflow to the cathode inlet of the fuel cell stack gradually diminishes over the bypass period, and when the airflow bypass is complete the cathode inlet is also instantaneously vented to a remote vent to eliminate pressure differentials across the stack.

  18. Staged venting of fuel cell system during rapid shutdown

    DOEpatents

    Clingerman, Bruce J.; Doan, Tien M.; Keskula, Donald H.

    2002-01-01

    A venting methodology and system for rapid shutdown of a fuel cell apparatus of the type used in a vehicle propulsion system. H.sub.2 and air flows to the fuel cell stack are slowly bypassed to the combustor upon receipt of a rapid shutdown command. The bypass occurs over a period of time (for example one to five seconds) using conveniently-sized bypass valves. Upon receipt of the rapid shutdown command, the anode inlet of the fuel cell stack is instantaneously vented to a remote vent to remove all H.sub.2 from the stack. Airflow to the cathode inlet of the fuel cell stack gradually diminishes over the bypass period, and when the airflow bypass is complete the cathode inlet is also instantaneously vented to a remote vent to eliminate pressure differentials across the stack.

  19. Subsurface Gas Flow and Ice Grain Acceleration within Enceladus and Europa Fissures: 2D DSMC Models

    NASA Astrophysics Data System (ADS)

    Tucker, O. J.; Combi, M. R.; Tenishev, V.

    2014-12-01

    The ejection of material from geysers is a ubiquitous occurrence on outer solar system bodies. Water vapor plumes have been observed emanating from the southern hemispheres of Enceladus and Europa (Hansen et al. 2011, Roth et al. 2014), and N2plumes carrying ice and ark particles on Triton (Soderblom et al. 2009). The gas and ice grain distributions in the Enceladus plume depend on the subsurface gas properties and the geometry of the fissures e.g., (Schmidt et al. 2008, Ingersoll et al. 2010). Of course the fissures can have complex geometries due to tidal stresses, melting, freezing etc., but directly sampled and inferred gas and grain properties for the plume (source rate, bulk velocity, terminal grain velocity) can be used to provide a basis to constrain characteristic dimensions of vent width and depth. We used a 2-dimensional Direct Simulation Monte Carlo (DSMC) technique to model venting from both axi-symmetric canyons with widths ~2 km and narrow jets with widths ~15-40 m. For all of our vent geometries, considered the water vapor source rates (1027­ - 1028 s-1) and bulk gas velocities (~330 - 670 m/s) obtained at the surface were consistent with inferred values obtained by fits of the data for the plume densities (1026 - 1028 s-1, 250 - 1000 m/s) respectively. However, when using the resulting DSMC gas distribution for the canyon geometries to integrate the trajectories of ice grains we found it insufficient to accelerate submicron ice grains to Enceladus' escape speed. On the other hand, the gas distributions in the jet like vents accelerated grains > 10 μm significantly above Enceladus' escape speed. It has been suggested that micron-sized grains are ejected from the vents with speeds comparable to the Enceladus escape speed. Here we report on these results including comparisons to results obtained from 1D models as well as discuss the implications of our plume model results. We also show preliminary results for similar considerations applied to Europa

  20. Building No. 902, detail of Mechanical Room door, including vent ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Building No. 902, detail of Mechanical Room door, including vent and conduit - Presidio of San Francisco, Enlisted Men's Barracks Type, West end of Crissy Field, between Pearce & Maudlin Streets, San Francisco, San Francisco County, CA

  1. Detail of southeast side of Facility 283. Compare roof vents ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail of southeast side of Facility 283. Compare roof vents to those on Facility 226. - U.S. Naval Base, Pearl Harbor, Storehouse for Defense Battalion Type, Between Port Royal Street & Fuller Way, Pearl City, Honolulu County, HI

  2. Tapped-Hole Vent Path

    NASA Technical Reports Server (NTRS)

    Chandler, J. A.

    1983-01-01

    Long helical vent path cools and releases hot pyrotechnical gas that exits along its spiraling threads. Current design uses 1/4-28 threads with outer diameter of stud reduced by 0.025 in. (0.62 mm). To open or close gassampler bottle, pyrotechnic charges on either one side or other of valve cylinder are actuated. Gases vented slowly over long path are cool enough to present no ignition hazard. Vent used to meter flow in refrigeration, pneumaticcontrol, and fluid-control systems by appropriately adjusting size and length of vent path.

  3. Are midwater shrimp trapped in the craters of submarine volcanoes by hydrothermal venting?

    NASA Astrophysics Data System (ADS)

    Wishner, Karen F.; Graff, Jason R.; Martin, Joel W.; Carey, S.; Sigurdsson, H.; Seibel, B. A.

    2005-08-01

    The biology of Kick'em Jenny (KEJ) submarine volcano, part of the Lesser Antilles volcanic arc and located off the coast of Grenada in the Caribbean Sea, was studied during a cruise in 2003. Hydrothermal venting and an associated biological assemblage were discovered in the volcanic crater (˜250 m depth). Warm water with bubbling gas emanated through rock fissures and sediments. Shrimp (some of them swimming) were clustered at vents, while other individuals lay immobile on sediments. The shrimp fauna consisted of 3 mesopelagic species that had no prior record of benthic or vent association. We suggest that these midwater shrimp, from deeper water populations offshore, were trapped within the crater during their downward diel vertical migration. It is unknown whether they then succumbed to the hostile vent environment (immobile individuals) or whether they are potentially opportunistic vent residents (active individuals). Given the abundance of submarine arc volcanoes worldwide, this phenomenon suggests that volcanic arcs could be important interaction sites between oceanic midwater and vent communities.

  4. Safe venting of hydrogen

    SciTech Connect

    Stewart, W.F.; Dewart, J.M.; Edeskuty, F.J.

    1990-01-01

    The disposal of hydrogen is often required in the operation of an experimental facility that contains hydrogen. Whether the vented hydrogen can be discharged to the atmosphere safely depends upon a number of factors such as the flow rate and atmospheric conditions. Calculations have been made that predict the distance a combustible mixture can extend from the point of release under some specified atmospheric conditions. Also the quantity of hydrogen in the combustible cloud is estimated. These results can be helpful in deciding of the hydrogen can be released directly to the atmosphere, or if it must be intentionally ignited. 15 refs., 5 figs., 2 tabs.

  5. Tornado protection by venting

    SciTech Connect

    Cavanagh, C.A.

    1987-01-01

    The purpose of this paper is to demonstrate the ability to protect a modern nuclear power plant from the effects of a tornado by the use of a system of venting in all safety-related structures outside of the containment. The paper demonstrates this by presenting a method of analysis and of equipment selection that fully complies with the intent and the letter of applicable federal regulatory guides. A report of an actual tornado in the City of Kalamazoo, Michigan, suggests that the concept of sealing a plant during a tornado may not always be applicable.

  6. Enhanced Emergency Smoke Venting

    DTIC Science & Technology

    1988-07-01

    Boeing Airworthiness Offices in both Renton and Everett. The search disclosed at least 26 letters between Boeing and the FAA on the subject of smoke...the ventilation airflow rates and utilizing the effect of the additional outflow valve. .-. 12 FAA Report No. DOT/ FAA /CT-86/41-I, " Aircraft ...lTr !r DOT/ FAA !CT-88/22 Enhanced Emergency FAA Technical Center Sm oke Atlantic City International Airport Venting N.J. 08405 T.DTIC, Q\\SEP 0 21988

  7. Hydraulic fracturing in tight, fissured media

    SciTech Connect

    Warpinski, N.R. )

    1991-02-01

    Large volumes of natural gas are found in tight, fissured reservoirs. Hydraulic fracturing can enhance recovery, but many complications, such as pressure-sensitive or accelerated leakoff, damage, and complex fracturing, arise during treatment of such reservoirs. This paper reports that special procedures generally should be considered during breakdown and fracturing of these reservoirs. In addition, the use of alternative stimulation strategies may be beneficial.

  8. 24 CFR 3280.611 - Vents and venting.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...) Materials—(1) Pipe. Vent piping shall be standard weight steel, wrought iron, brass, copper tube DWV, listed plastic, cast iron or other approved or listed materials. (2) Fittings. Appropriate fittings shall be used for all changes in direction or size and where pipes are joined. The material and design of vent...

  9. 24 CFR 3280.611 - Vents and venting.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...) Materials—(1) Pipe. Vent piping shall be standard weight steel, wrought iron, brass, copper tube DWV, listed plastic, cast iron or other approved or listed materials. (2) Fittings. Appropriate fittings shall be used for all changes in direction or size and where pipes are joined. The material and design of vent...

  10. Are eruptions from linear fissures and caldera ring dykes more likely to produce pyroclastic flows?

    NASA Astrophysics Data System (ADS)

    Jessop, D. E.; Gilchrist, J.; Jellinek, A. M.; Roche, O.

    2016-11-01

    Turbulent volcanic jets are produced by highly-energetic explosive eruptions and may form buoyant plumes that rise many tens of kilometres into the atmosphere to form umbrella clouds or collapse to generate ground-hugging pyroclastic flows. Ash injected into the atmosphere can be transported for many hundreds of kilometres with the potential to affect climate, disrupt global air travel and cause respiratory health problems. Pyroclastic flows, by contrast, are potentially catastrophic to populations and infrastructure close to the volcano. Key to which of these two behaviours will occur is the extent to which the mechanical entrainment and mixing of ambient air into the jet by large (entraining) eddies forming the jet edge changes the density of the air-ash mixture: low entrainment rates lead to pyroclastic flows and high entrainment rates give rise to buoyant plumes. Recent experiments on particle-laden (multi-phase) volcanic jets from flared and straight-sided circular openings suggest that the likelihood for buoyant plumes will depend strongly on the shape and internal geometry of the vent region. This newly recognised sensitivity of the fate of volcanic jets to the structure of the vent is a consequence of a complex dynamic coupling between the jet and entrained solid particles, an effect that has generally been overlooked in previous studies. Building on this work, here we use an extensive series of experiments on multi-phase turbulent jets from analogue linear fissures and annular ring fractures to explore whether the restrictive vent geometry during cataclysmic caldera-forming (CCF) eruptions will ultimately lead a relatively greater frequency of pyroclastic flows than eruptions from circular vents on stratovolcanoes. Our results, understood through scaling analyses and a one-dimensional theoretical model, show that entrainment is enhanced where particle motions contribute angular momentum to entraining eddies. However, because the size of the entraining

  11. Anatomy and approaches along the cerebellar-brainstem fissures.

    PubMed

    Matsushima, Ken; Yagmurlu, Kaan; Kohno, Michihiro; Rhoton, Albert L

    2016-01-01

    OBJECT Fissure dissection is routinely used in the supratentorial region to access deeply situated pathology while minimizing division of neural tissue. Use of fissure dissection is also practical in the posterior fossa. In this study, the microsurgical anatomy of the 3 cerebellar-brainstem fissures (cerebellomesencephalic, cerebellopontine, and cerebellomedullary) and the various procedures exposing these fissures in brainstem surgery were examined. METHODS Seven cadaveric heads were examined with a microsurgical technique and 3 with fiber dissection to clarify the anatomy of the cerebellar-brainstem and adjacent cerebellar fissures, in which the major vessels and neural structures are located. Several approaches directed along the cerebellar surfaces and fissures, including the supracerebellar infratentorial, occipital transtentorial, retrosigmoid, and midline suboccipital approaches, were examined. The 3 heads examined using fiber dissection defined the anatomy of the cerebellar peduncles coursing in the depths of these fissures. RESULTS Dissections directed along the cerebellar-brainstem and cerebellar fissures provided access to the posterior and posterolateral midbrain and upper pons, lateral pons, floor and lateral wall of the fourth ventricle, and dorsal and lateral medulla. CONCLUSIONS Opening the cerebellar-brainstem and adjacent cerebellar fissures provided access to the brainstem surface hidden by the cerebellum, while minimizing division of neural tissue. Most of the major cerebellar arteries, veins, and vital neural structures are located in or near these fissures and can be accessed through them.

  12. Earth Fissures in Su-Xi-Chang Region, Jiangsu, China

    NASA Astrophysics Data System (ADS)

    Wang, Guang-ya; You, Greg; Zhu, Jin-qi; Yu, Jun; Li, Wei

    2016-11-01

    The earth fissures in the Su-Xi-Chang area are caused by differential land subsidence due to long-term excessive groundwater withdrawal and controlled by the bedrock ridge or cliff underlying. There have been more than 15 earth fissures in the area since 1989. The field investigations have lasted for more than 20 years. The earth fissures generally have a main fissure and a number of secondary ones parallel to the main one. The main fissure (crack) has a scarp, is steeply dipping, and can be more than 2000 m long. Geophysical surveys (2D or 3D seismic investigation, controlled source audio frequency magnetotelluric sounding, and electric sounding) combined with geological drilling are effective for the investigation of earth fissures. Geodetic leveling is effective to monitor the ground deformation across the earth fissure, so is the extensometer for the opening of the fissure. The activities of earth fissures are directly related to different stages of land subsidence and controlled by geological abnormalities. Most earth fissures in the area are still active.

  13. Lung fissure detection in CT images using global minimal paths

    NASA Astrophysics Data System (ADS)

    Appia, Vikram; Patil, Uday; Das, Bipul

    2010-03-01

    Pulmonary fissures separate human lungs into five distinct regions called lobes. Detection of fissure is essential for localization of the lobar distribution of lung diseases, surgical planning and follow-up. Treatment planning also requires calculation of the lobe volume. This volume estimation mandates accurate segmentation of the fissures. Presence of other structures (like vessels) near the fissure, along with its high variational probability in terms of position, shape etc. makes the lobe segmentation a challenging task. Also, false incomplete fissures and occurrence of diseases add to the complications of fissure detection. In this paper, we propose a semi-automated fissure segmentation algorithm using a minimal path approach on CT images. An energy function is defined such that the path integral over the fissure is the global minimum. Based on a few user defined points on a single slice of the CT image, the proposed algorithm minimizes a 2D energy function on the sagital slice computed using (a) intensity (b) distance of the vasculature, (c) curvature in 2D, (d) continuity in 3D. The fissure is the infimum energy path between a representative point on the fissure and nearest lung boundary point in this energy domain. The algorithm has been tested on 10 CT volume datasets acquired from GE scanners at multiple clinical sites. The datasets span through different pathological conditions and varying imaging artifacts.

  14. Fissure Integrity and Volume Reduction in Emphysema: A Retrospective Study.

    PubMed

    de Oliveira, Hugo Goulart; de Oliveira, Silvia Martins; Rambo, Rafael Ramos; de Macedo Neto, Amarilio Vieira

    2016-01-01

    One-way endobronchial valves (EBVs) relieve symptoms of emphysema, particularly in patients without collateral ventilation between the target and adjacent lobes. Pretreatment knowledge of fissure integrity could serve as an aid in indicating EBV interventions. This study aimed to investigate the relationship between software-measured lung fissure integrity and clinically relevant lung volume reduction (≥350 ml) in emphysema patients treated with one-way EBVs using a lobar exclusion strategy. Of 108 patients treated between March 2008 and July 2014, 38 had both baseline and follow-up computed tomography (CT) scans acquired following a specific protocol for quantitative CT analysis and were included in the study (total of 39 treatments, two lungs treated in 1 patient). Outcome measures were fissure integrity measured on baseline CT scans, difference between pre- and postoperative lung volume (considering the lowest measured postoperative volume), and correlation between fissure integrity and volume change. Fissure integrity ≥75% correlated with volume reduction ≥350 ml (Spearman coefficient: -0.65; p < 0.01). The mean and median volume reductions were 1,223.96 ± 907.5 ml and 663 ml, respectively, for lungs with fissure integrity ≥75% (n = 31). The accuracy of fissure integrity ≥75% in predicting a volume reduction was 87.2%. The positive predictive value of fissure integrity ≥75% to predict a volume reduction ≥350 ml was 83.9%, and it was 70% for fissure integrity 75-90% and 90.5% for fissure integrity >90%. A target lobe volume reduction using EBVs is possible with lung fissure integrity ≥75%. For patients with fissure integrity between 75 and 90%, a further evaluation of interlobar ventilation should be performed. A clinically relevant volume reduction following treatment with EBVs is likely with any level of fissure integrity >90%. © 2016 S. Karger AG, Basel.

  15. Visual Observations and Geologic Settings of the Newly-Discovered Black Smoker Vent Sites Across the Galapagos Ridge-Hotspot Intersection

    NASA Astrophysics Data System (ADS)

    Anderson, P.; Haymon, R.; MacDonald, K.; White, S.

    2006-12-01

    Nearly one-fifth of the global mid-ocean ridge is hotspot-affected, yet very little is known about how hotspots affect quantity and distribution of high-temperature hydrothermal vents along the ridge. During the 2005-06 GalAPAGoS expedition, acoustic and plume sensor surveys were conducted across the Galapagos ridge- hotspot intersection, lon. 94.5ºW- lon. 89.5ºW, to map fine scale geologic features and locate hydrothermal plumes emanating from the ridge crest. Where significant plumes were detected, the Medea fiber-optic camera sled was used successfully to find and image high-temperature vents on the seafloor. With Medea we discovered and imaged the first active and recently extinct black smokers known along the entire Galapagos Spreading Center (GSC), and documented the geologic setting of these vents. The Medea survey imaged numerous inactive vents as well as 3 active high-temperature vent fields along the ridge at 94º 04.5'W (Navidad Site), 91º56.2'W (Iguanas Site) and 91º54.3'W (Pinguinos Site). Two recently extinct vent fields also were identified at 91º23.4'-23.7'W and 91º13.8'W. All of the high-temperature vent sites that we identified along the GSC are found above relatively shallow AMC reflectors and are located in the middle 20% of ridge segments. Without exception the vent sites are located along fissures atop constructional axial volcanic ridges (AVR's) composed of relatively young pillow basalts. In some cases, the vents were associated with collapses adjacent to the fissures. The fissures appear to be eruptive sources of the pillow lavas comprising the AVR's. Video images of the chimneys show mature, cylindrical structures, up to 14m high; little diffuse flow; few animals; and some worm casts and dead clam shells, suggesting prior habitation. We conclude that distribution of the vents is controlled by magmatic processes, (i.e., by locations of shallow AMC magma reservoirs and eruptive fissures above dike intrusions), and that there is

  16. Water vent design for Space Station Freedom

    NASA Astrophysics Data System (ADS)

    Miernik, Janie H.; Worden, Edson A.; Bedard, John E.; Lieu, Bing H.

    1992-07-01

    Space Stadon Freedom (SSF) will be required to vent water during non-quiescent periods. During Man Tended Configuration (MTC), before the Environmental Control and Life Support System (ECLSS) water loop is closed, humidity condensate will be periodically vented. At Permanently Manned Configuration (PMC), water will be vented on contingency if there is excess water on SSF. The thrust due to venting must be minimized to be considered non-propulsive. Also, ice formation and clogging of the vent nozzle must be avoided. Many aspects of the Space Shuttle water vent design were utilized in development of the preliminary SSF water vent design presented in this paper. Design modifications which improved the shuttle vent as well as those necessary for SSF are discussed. The exterior vent location, direction and environment on SSF are unique compared to previous space water vent designs. From data collected in the vent tests and analyses, a finalized SSF water vent design will be developed.

  17. EVALUATION OF SOIL VENTING APPLICATION

    EPA Science Inventory

    The ability of soil venting to inexpensively remove large amounts of volatile organic compounds (VOCs) from contaminated soils is well established. However, the time required using venting to remediate soils to low contaminant levels often required by state and federal regulators...

  18. Efficacy of nitroglycerine ointment in the treatment of pediatric anal fissure.

    PubMed

    Joda, Ali E; Al-Mayoof, Ali F

    2017-04-08

    Anal fissure is the most common anal disease in children. In the past few decades, the understanding of its pathophysiology has led to a progressive reduction in invasive procedures in favor of conservative treatment based on stool softeners and the relaxation of the anal sphincter. This randomized controlled study assessed the safety and efficacy of nitroglycerine (NTG) ointment in the treatment of pediatric anal fissure, which had not yet been proved. An unequal randomized controlled study included 105 pediatric patients with anal fissure who had presented to the private and outpatient clinics of the Central Teaching Hospital of Pediatrics during the period from February 2015 to May 2016. The control group consisted of 70 patients. Both groups were treated with classical conservative therapy of sitz bath, stool softener, and local anesthetic. In the second group, chemical sphincterotomy with 0.2% NTG ointment was used in 35 patients, and was applied at the anal canal twice daily for 8weeks. The primary outcomes of symptomatic improvement and healed fissure, as well as side effects, were analyzed. The average age of patients was 2years (range, 4months to 5years). Patients in the NTG group had 77% symptomatic relief and 60% healed fissure compared to the control group, which had 54% and 32.8% respectively. All were statistically significant. No serious adverse effects were noticed during the treatment period. The use of 0.2% NTG ointment is an effective therapy for anal fissure in children in terms of good healing rate and rapid symptom relief, but it has the drawback of a long treatment period, making patient compliance more difficult, in addition to the problems of tolerance and recurrence. Prospective randomized controlled study (treatment study). Type 2. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Clinical and gross pathologic findings of complicated vertical fissures with digital dermatitis in a dairy herd.

    PubMed

    Nouri, Mohsen; Ashrafi Helan, Javad

    2012-01-01

    Careful antemortem examination and interpretation of findings, assisted by good clinical records, do much to throw light on the nature of vertical fissure in cattle. During an eight month period of investigation, 13 (3.2%) lame cows with vertical fissure out of 52 Holstein cows with different claw fissures were selected for clinical and gross pathological purposes in a commercial dairy farm with 400 milking cows in Nazarabad, Iran. The cows were 2.5 to10.5 years old. The prevalence rate of vertical fissure was 3.2 per cent. The prevalence rate of claw lesion in the hind limb (69.2%) was higher than that of fore limb (30.7%). The type of vertical fissures were 4 (38.4%), 5 (23.0%), 2 (23.0%) and 3 (15.3%), respectively. Locomotion scoring assessment of 13 culled lame cows showed score ranged from grade 3 (30.7%) to 4 (61.5%). The herd had endemic digital dermatitis infection with prevalence in the adult herd of over 34.2%. The affected claws were more boxy than normal and the abaxial wall was convex in all directions. The lame cows had typical stance such as hobbyhorse or cross legged stance. This study shows that more research is needed both on the economic impact of vertical fissures in dairy cows and on the microbiological study of spirochaetes of the genus Treponema. This study recommends that owners of dairy farm should try to control digital dermatitis with preventative herd strategies.

  20. Cyp1b1 Regulates Ocular Fissure Closure Through a Retinoic Acid–Independent Pathway

    PubMed Central

    Williams, Antionette L.; Eason, Jessica; Chawla, Bahaar; Bohnsack, Brenda L.

    2017-01-01

    Purpose Mutations in the CYP1B1 gene are the most commonly identified genetic causes of primary infantile-onset glaucoma. Despite this disease association, the role of CYP1B1 in eye development and its in vivo substrate remain unknown. In the present study, we used zebrafish to elucidate the mechanism by which cyp1b1 regulates eye development. Methods Zebrafish eye and neural crest development were analyzed using live imaging of transgenic zebrafish embryos, in situ hybridization, immunostaining, TUNEL assay, and methylacrylate sections. Cyp1b1 and retinoic acid (RA) levels were genetically (morpholino oligonucleotide antisense and mRNA) and pharmacologically manipulated to examine gene function. Results Using zebrafish, we observed that cyp1b1 was expressed in a specific spatiotemporal pattern in the ocular fissures of the developing zebrafish retina and regulated fissure patency. Decreased Cyp1b1 resulted in the premature breakdown of laminin in the ventral fissure and altered subsequent neural crest migration into the anterior segment. In contrast, cyp1b1 overexpression inhibited cell survival in the ventral ocular fissure and prevented fissure closure via an RA-independent pathway. Cyp1b1 overexpression also inhibited the ocular expression of vsx2, pax6a, and pax6b and increased the extraocular expression of shha. Importantly, embryos injected with human wild-type but not mutant CYP1B1 mRNA also showed colobomas, demonstrating the evolutionary and functional conservation of gene function between species. Conclusions Cyp1b1 regulation of ocular fissure closure indirectly affects neural crest migration and development through an RA-independent pathway. These studies provide insight into the role of Cyp1b1 in eye development and further elucidate the pathogenesis of primary infantile-onset glaucoma. PMID:28192799

  1. Remote sensing and petrological observations on the 2012-2013 fissure eruption at Tolbachik volcano, Kamchatka: Implications for reconstruction of the eruption chronology

    NASA Astrophysics Data System (ADS)

    Melnikov, Dmitry; Volynets, Anna O.

    2015-12-01

    We present a reconstruction of the chronological sequence of events that took place during the first days of the 2012-2013 Tolbachik fissure eruption using petrological data and remote sensing methods. We were forced to use this approach because bad weather conditions did not allow direct observations during the first two days of the eruption. We interpreted infrared images from the scanning radiometer VIIRS Suomi NPP and correlated the output with the results of the geochemical study, including comparison of the ash, deposited at the period from 27 to 29 November, with the samples of lava and bombs erupted from the Menyailov and Naboko vents. We argue that the compositional change observed in the eruption products (the decrease of SiO2 concentration and K2O/MgO ratio, increase of MgO concentration and Mg#) started approximately 24 h after the eruption began. At this time the center of activity moved to the southern part of the fissure, where the Naboko group of vents was formed; therefore, this timeframe also characterizes the timing of the Naboko vent opening. The Naboko group of vents remained active until the end of eruption in September 2013.

  2. Dynamics and functional model of the 2012-13 flank fissure eruption of Tolbachik volcano in Kamchatka, Russia

    NASA Astrophysics Data System (ADS)

    Belousov, Alexander; Belousova, Marina; Edwards, Benjamin

    2017-04-01

    The 2012-13 flank fissure eruption of Tolbachik in Kamchatka Peninsula lasted more than nine months and discharged 0.55 cub.km DRE of basaltic trachyandesite magma. It is one of the most voluminous historical eruptions of mafic magma at subduction-related volcano globally, and is the second largest in Kamchatka. We present a broad overview of the eruption as well as a model for the magma storage and transport system of Plosky Tolbachik Volcano. The 2012-13 eruption was preceded by five months of elevated seismicity and ground inflation, both of which peaked a day before the eruption commenced on 27 November 2012. The batch of high-Al magma ascended from depths of 5-10 km; its apical part contained 54-55 wt.% SiO2, and the main body 52-53 wt.% SiO2. The eruption started by the opening of a 6 km-long radial fissure on the southwestern slope of the volcano that fed multi-vent phreatomagmatic and magmatic explosive activity, as well as intensive effusion of lava with an initial discharge of 440 cub.m/s. After 10 days the eruption continued only at the lower part of the fissure, where explosive and effusive activity of Hawaiian-Strombolian type occurred from a lava pond in the crater of the main growing scoria cone. The discharge rate for the nine month long, effusion-dominated eruption gradually declined from 140 to 18 cub.m/s and formed a compound lava field with a total area of 36 sq.km; the effusive activity evolved from high-discharge channel-fed 'a'a lavas to dominantly low-discharge tube-fed pahoehoe lavas. On 23 August, the effusion of lava ceased and the intra-crater lava pond drained. Weak Strombolian-type explosions continued for several more days on the crater bottom until the end of the eruption around 5 September 2013. The volcanic system, comprising the stratovolcano Plosky Tolbachik and its two radial volcanic rifts, produces alternating eruptions of two genetically related magma types: high-Al basalt (eruptions at the summit and along both rift zones

  3. Distributed Computing for Seismic Data Retrieval using FISSURES DHI Client FMI Implimented from MatSeis 1.9

    NASA Astrophysics Data System (ADS)

    Hart, D. M.; Li, Q.; Creager, K. C.; Ning, R.; Crotwell, H. P.; Zuzlewski, S.; Hellman, S. B.; Schoch, K. S.; Laughbon, C. J.; Stromme, S. R.

    2004-12-01

    Three software development efforts have recently combined to allow a seamless method for obtaining data from the IRIS DMC over the Internet and analyzing it in MATLAB. During the past few years IRIS has constructed the initial framework and definitions for FISSURES servers and Data Handling Interface (DHI) clients. FISSURES uses the distributed computing language Common Object Request Broker Architecture (CORBA), which allows software systems to work across the Internet in a platform independent and computer-language neutral manner. Starting from the FISSURES object model three seismic services have been defined: event, network and seismogram. From these three object types a DHI client is used to access information through FISSURES services. Using the University of Washington developed FISSURES-Matlab-Interface (FMI) DHI client, all three FISSURES objects can be accessed via the Internet and downloaded into local MATLAB objects, allowing access to earthquake event catalogs, seismograms, network and instrument information. The DHI client FMI can be implemented from MatSeis. MatSeis, developed at Sandia National Laboratory, is a MATLAB based, Graphical User Interface (GUI) controlled software package with seismic data visualization, signal processing, and database importing and exporting capabilities, to list just a few. In this poster, we will discuss the seismic data retrieval currently prototyped for the IRIS DMC, as well as the planned connections to the Northern California Earthquake Data Center (NCEDC), Southern California Earthquake Data Center (SCEDC), and South Carolina Earth Physics Project (SCEPP) data center.

  4. Rise and Collapse of Volcanic Plumes Produced By Explosive Basaltic Fissure Eruptions

    NASA Astrophysics Data System (ADS)

    Paillat, S.; Kaminski, E. C.

    2014-12-01

    Explosive basaltic fissure eruptions, which release large amounts of sulfur gases in the atmosphere, can have a big impact on climate. The effect on climate depends on the rate of gas injection above the tropopause. The key parameter is the height reached by the eruptive plume as a function of mass flux and entrainment rate. We propose a model of entrainment in 2D volcanic plumes based on lab scale experiments on turbulent jets and plumes. In this model, entrainment varies with the Richardson number and we predict that the height of the column critically depends on the source buoyancy flux determined by the eruptive temperature and the amount of gas in the volcanic mixture at the vent. We obtain that "hot" basaltic planar plumes form stable eruptive columns, even for large eruption rates. Only if fragmentation is not efficient enough, the column collapse will prevent the injection of gas in the stratosphere.

  5. [Fissure sealants--5 years of use].

    PubMed

    Azul, A M

    1990-01-01

    This study assesses the caries prevalence, retention and cost-effectiveness of a pit and fissure sealant in a children population with 622 cases, 5 years after a single application of an auto-polymerized sealant to permanent molars. The status of the sealant and the presence of caries or restaurations on the sealed teeth was assessed. In a self-controlled group of children, the prevalence of disease (caries and restaurations) was also assessed in non-sealed teeth, for comparison. The sealant application was compared with Class I-restauration with amalgam for cost-effectiveness analysis.

  6. Monitoring an eruption fissure in 3D: video recording, particle image velocimetry and dynamics

    NASA Astrophysics Data System (ADS)

    Witt, Tanja; Walter, Thomas R.

    2015-04-01

    The processes during an eruption are very complex. To get a better understanding several parameters are measured. One of the measured parameters is the velocity of particles and patterns, as ash and emitted magma, and of the volcano itself. The resulting velocity field provides insights into the dynamics of a vent. Here we test our algorithm for 3 dimensional velocity fields on videos of the second fissure eruption of Bárdarbunga 2014. There we acquired videos from lava fountains of the main fissure with 2 high speed cameras with small angles between the cameras. Additionally we test the algorithm on videos from the geyser Strokkur, where we had 3 cameras and larger angles between the cameras. The velocity is calculated by a correlation in the Fourier space of contiguous images. Considering that we only have the velocity field of the surface smaller angles result in a better resolution of the existing velocity field in the near field. For general movements also larger angles can be useful, e.g. to get the direction, height and velocity of eruption clouds. In summary, it can be stated that 3D velocimetry can be used for several application and with different setup due to the application.

  7. Lava fountaining and vent morphology analyzed at the 2014 Holuhraun eruption, Iceland, by video monitoring and topographic mapping

    NASA Astrophysics Data System (ADS)

    Witt, Tanja; Walter, Thomas R.; Müller, Daniel; Schöpa, Anne; Steinke, Bastian; Gudmundsson, Magnus T.

    2017-04-01

    Fissure eruptions are commonly linked to magma at depth and lava fountaining at the surface. Shortly after the onset of eruptive activity, erupting fissures begin to focus their activity at distinct vents, resulting in the formation of morphological craters shaping the sites of the eruption. A detailed analysis of the morphological development during fissure eruptions and the link to the lava fountain activity has not been conducted in large detail so far. To analyze the lava fountains in height and venting activity and compare that to the vent morphology, we used videos recorded from different locations at a distance up to 2 km during the first few days of the 2014 main Holuhraun eruption, Iceland. The videos have lengths of up to 2 hours and focus on the main eruptive vents. To investigate the morphology of the developing craters after the eruption in detail, a fieldwork mapping project combining terrestrial laser scanning (TLS) and unmanned aerial vehicle (UAV) based aerophoto analysis was realized in summer 2015. From the data, we generated a locally high-resolution digital elevation model by structure from motion (SfM) at the eruptive vents. We found that at the locations of highest venting activity the lava spatters formed craters during the very initial phase of the eruption of 4 days. Comparison to post-eruptive topography shows that the craters remain similar in shape, but increase in size as the eruption progressed. Therefore, the remaining morphology is mostly conditioned in the beginning of the eruption. Furthermore, the smaller craters of Sudri show distinct lava fountains, which are much smaller and thinner than the ones from the bigger Baugur crater. Comparably, the activity of the lava fountains is a little bit lower at Sudri. The Baugur crater is the locus of several high lava fountains, which slightly move in location by up to 20 m and intertwine/overlap each other. This might be due to the presence of the large lava lake at the Baugur crater. In

  8. Identification of possible recent water/lava source vents in the Cerberus plains: Stratigraphic andcrater count age constraints

    NASA Astrophysics Data System (ADS)

    Thomas, Rebecca J.

    2013-04-01

    In order to investigate sources of lava and water to the Cerberus plains of Mars, geomorphological mapping on High Resolution Imaging Science Experiment (HiRISE) images was carried out to reveal the history of activity of fissures and pits which lie upstream of channels and deposits associated with a wrinkle ridge near Cerberus Fossae. The fissures and pits are superbly exposed and imaged, and flows and channels emanate directly from them, interpreted as clear evidence that these are vents. The mapping establishes stratigraphic relationships between the plains and the channels and deposits originating from the vents, establishing the vent history. For example, to the south of the wrinkle ridge, both incised channels and leveed flows extend onto the southern plain and are clearly the final phase of plains-forming activity. Conversely, to the north, vent-sourced channels only incise the plain close to the ridge—beyond that, they are overlain by large-scale regional flows that appear to have originated from the direction of Athabasca Valles. In the southeast, there is evidence of contemporaneity between vent-sourced activity and large-scale plains-forming flow that was not sourced from the vents, indicating that activity here was part of a broader process of Cerberus plains formation from multiple sources. Crater counts show all the activity to be Late Amazonian, with the latest activity tentatively dating to circa 11 Ma. Thus, this study implies that very recent outflows from these vents contributed to the formation of the Cerberus plains and constrains the timing and local flow direction of plains-forming deposits from other sources.

  9. Provisions for containment venting in Germany

    SciTech Connect

    Wilhelm, J.G.

    1997-08-01

    In this short paper an overlook is given of the systems developed in Germany for filtered containment venting and their implementation in nuclear power plants. More information on the development can be found in the Proceedings of the DOE/NRC Aircleaning Conferences. In Germany, 28.8 % of the electric energy is produced by 19 nuclear power reactors. No new power reactor is expected to be built at least within the next ten years, but France and Germany cooperate in the development of a future European Power Reactor (ERP). This reactor type will be fitted with a core catcher and passive cooling in order to avoid serious consequences of a hypothetical core meltdown accident so that provisions for containment venting are not required. 3 refs., 6 figs., 1 tab.

  10. Simulating a Submarine Hydrothermal Vent

    NASA Image and Video Library

    2013-01-16

    A team of scientists at NASA Jet Propulsion Laboratory is testing whether organic molecules can be brewed in a simulated ocean vent. Pictured here is Lauren White, a member of the NASA Astrobiology Icy Worlds team.

  11. Cement penetration after patella venting.

    PubMed

    Jones, Christopher W; Lam, Li-On; Butler, Adam; Wood, David J; Walsh, William R

    2009-01-01

    There is a high rate of patellofemoral complications following total knee arthroplasty. Optimization of the cement-bone interface by venting and suction of the tibial plateau has been shown to improve cement penetration. Our study was designed to investigate if venting the patella prior to cementing improved cement penetration. Ten paired cadaver patellae were allocated prior to resurfacing to be vented or non-vented. Bone mineral density (BMD) was measured by DEXA scanning. In vented specimens, a 1.6 mm Kirschner wire was used to breach the anterior cortex at the center. Specimens were resurfaced with standard Profix instrumentation and Versabond bone cement (Smith and Nephew PLC, UK). Cement penetration was assessed from Faxitron and sectioned images by a digital image software package (ImageJ V1.38, NIH, USA). Wilcoxon rank sum test was used to assess the difference in cement penetration between groups. The relationship between BMD and cement penetration was analyzed by Pearson correlation coefficient. There was a strong negative correlation between peak BMD and cement penetration when analyzed independent of experimental grouping (r(2)=-0.812, p=0.004). Wilcoxon rank sum testing demonstrated no significant difference (rank sum statistic W=27, p=0.579) in cement penetration between vented (10.53%+/-4.66; mean+/-std dev) and non-vented patellae (11.51%+/-6.23; mean+/-std dev). Venting the patella using a Kirschner wire does not have a significant effect on the amount of cement penetration achieved in vitro using Profix instrumentation and Versabond cement.

  12. Fine Mapping and Introgressing a Fissure Resistance Locus

    USDA-ARS?s Scientific Manuscript database

    Rice (Oryza sativa L.) kernel fissuring is a major concern of both rice producers and millers. Fissures are small cracks in rice kernels that increase breakage among kernels when transported or milled, which decrease the value of processed rice. This study employed molecular gene tagging methods to ...

  13. Anal fissures associated with targeted therapies in ovarian cancer.

    PubMed

    Squires, Jennifer

    2009-12-01

    Although ovarian cancer remains a leading cause of gynecologic cancer death, targeted therapies are improving patient outcomes. Anal fissures are a side effect of targeted therapies that can disrupt or stop treatment regimens. Diagnosis and management of anal fissures by advanced practice nurses are crucial for maintaining the quality of life of patients with ovarian cancer.

  14. Vent sizing: analysis of the blowdown of a hybrid non tempered system.

    PubMed

    Véchot, Luc; Minko, Wilfried; Bigot, Jean-Pierre; Kazmierczak, Marc; Vicot, Patricia

    2011-07-15

    The runaway and blowdown of a non tempered hybrid chemical system (30% cumene hydroperoxide) exposed to an external heat input was investigated using a 0.1l scale tool. The maximum temperature and the maximum temperature rise rate were showed to be sensitive to the vent size. An Antoine type correlation between the maximum temperatures and pressures was observed. These resulted from the presence of vapour, mainly generated by the reaction products. Increasing the initial filling ratio resulted in an earlier vent opening but did not have a significant influence on the blow-down. Three types of mass venting behaviour were observed, when changing the vent area to volume ratio (A/V): • for large A/V, two-phase venting occurred from the vent opening until the end of the second pressure peak; • for medium A/V, two-phase venting occurred before and after the turnaround. The data seem to indicate that gas only venting occurred at turn-around; • for low A/V, two-phase venting was observed only after the second pressure peak. Two-phase venting after the second pressure peak probably results from the boiling of the hot reaction products at low pressure.

  15. A biogeographic network reveals evolutionary links between deep-sea hydrothermal vent and methane seep faunas.

    PubMed

    Kiel, Steffen

    2016-12-14

    Deep-sea hydrothermal vents and methane seeps are inhabited by members of the same higher taxa but share few species, thus scientists have long sought habitats or regions of intermediate character that would facilitate connectivity among these habitats. Here, a network analysis of 79 vent, seep, and whale-fall communities with 121 genus-level taxa identified sedimented vents as a main intermediate link between the two types of ecosystems. Sedimented vents share hot, metal-rich fluids with mid-ocean ridge-type vents and soft sediment with seeps. Such sites are common along the active continental margins of the Pacific Ocean, facilitating connectivity among vent/seep faunas in this region. By contrast, sedimented vents are rare in the Atlantic Ocean, offering an explanation for the greater distinction between its vent and seep faunas compared with those of the Pacific Ocean. The distribution of subduction zones and associated back-arc basins, where sedimented vents are common, likely plays a major role in the evolutionary and biogeographic connectivity of vent and seep faunas. The hypothesis that decaying whale carcasses are dispersal stepping stones linking these environments is not supported.

  16. Potential biomass in deep-sea hydrothermal vent ecosystem

    NASA Astrophysics Data System (ADS)

    Nakamura, K.; Takai, K.

    2012-12-01

    Since the first discovery of black smoker vents hosting chemosynthetic macrofaunal communities (Spiess et al., 1980), submarine hydrothermal systems and associated biota have attracted interest of many researchers (e.g., Humphris et al., 1995; Van Dover, 2000; Wilcock et al., 2004). In the past couple of decades, particular attention has been paid to chemolithoautotrophic microorganisms that sustain the hydrothermal vent-endemic animal communities as the primary producer. This type of microorganisms obtains energy from inorganic substances (e.g., sulfur, hydrogen, and methane) derived from hydrothermal vent fluids, and is often considered as an important modern analogue to the early ecosystems of the Earth as well as the extraterrestrial life in other planets and moons (e.g., Jannasch and Mottl, 1985; Nealson et al., 2005; Takai et al., 2006). Even today, however, the size of this type of chemosynthetic deep-sea hydrothermal vent ecosystem is largely unknown. Here, we present geophysical and geochemical constraints on potential biomass in the deep-sea hydrothermal vent ecosystem. The estimation of the potential biomass in the deep-sea hydrothermal vent ecosystem is based on hydrothermal fluid flux calculated from heat flux (Elderfield and Schltz, 1996), maximum chemical energy available from metabolic reactions during mixing between hydrothermal vent fluids and seawater (McCollom, 2007), and maintenance energy requirements of the chemolithoautotrophic microorganisms (Hoehler, 2004). The result shows that the most of metabolic energy sustaining the deep-sea hydrothermal vent ecosystem is produced by oxidation reaction of reduced sulfur, although some parts of the energy are derived from hydrogenotrophic and methanotrophic reactions. The overall total of the potential biomass in deep-sea hydrothermal vent ecosystem is calculated to be much smaller than that in terrestrial ecosystems including terrestrial plants. The big difference in biomass between the

  17. Tongue fissure extraction and classification using hyperspectral imaging technology.

    PubMed

    Li, Qingli; Wang, Yiting; Liu, Hongying; Sun, Zhen; Liu, Zhi

    2010-04-10

    Tongue fissures, an important feature on the tongue surface, may be pathologically related to some diseases. Most existing tongue fissure extraction methods use tongue images captured by traditional charge coupled device cameras. However, these conventional methods cannot be used for an accurate analysis of the tongue surface due to limited information from the images. To solve this, a hyperspectral tongue imager is used to capture tongue images instead of a digital camera. New algorithms for automatic tongue fissure extraction and classification, based on hyperspectral images, are presented. Both spectral and spatial information of the tongue surface is used to segment the tongue body and extract tongue fissures. Then a classification algorithm based on a hidden Markov model is used to classify tongue fissures into 12 typical categories. Results of the experiment show that the new method has good performance in terms of the classification rates of correctness.

  18. Impact de la preparation des anodes crues et des conditions de cuisson sur la fissuration dans des anodes denses

    NASA Astrophysics Data System (ADS)

    Amrani, Salah

    classifier les differentes fissurations en plusieurs categories en se basant sur certains criteres tels que le type de fissures (horizontale, verticale et inclinee), leurs localisations longitudinales (bas, milieu et haut de l'anode) et transversales (gauche, centrale et droite). Les effets de la matiere premiere, les parametres de fabrication des anodes crues ainsi que les conditions de cuisson sur la fissuration ont ete etudies. La fissuration des anodes denses en carbones cause un serieux probleme pour l'industrie d'aluminium primaire. La realisation de ce projet a permis la revelation de differents mecanismes de fissuration, la classification de fissuration par plusieurs criteres (position, types localisation) et l'evaluation de l'impact de differents parametres sur la fissuration. Les etudes effectuees dans le domaine de cuisson ont donne la possibilite d'ameliorer l'operation et reduire la fissuration des anodes. Le travail consiste aussi a identifier des techniques capables d'evaluer la qualite d'anodes (l'ultrason, la tomographie et la distribution de la resistivite electrique). La fissuration des anodes en carbone est consideree comme un probleme complexe, car son apparition depend de plusieurs parametres repartis sur toute la chaine de production. Dans ce projet, plusieurs nouvelles etudes ont ete realisees, et elles permettent de donner de l'originalite aux travaux de recherches faits dans le domaine de la fissuration des anodes de carbone pour l'industrie de l'aluminium primaire. Les etudes realisees dans ce projet permettent d'ajouter d'un cote, une valeur scientifique pour mieux comprendre le probleme de fissuration des anodes et d'un autre cote, d'essayer de proposer des methodes qui peuvent reduire ce probleme a l'echelle industrielle.

  19. The formation and extent of earth fissure in Shuangbutou, Beijing

    NASA Astrophysics Data System (ADS)

    Zhang, Youquan; Wu, Xun; Ren, Fangwei; Fu, Dequan; Wang, Rong; Wang, Haigang

    2017-04-01

    A 8.6-km-long earth fissure began to form in 2013 and currently affect the area in eastern Beijing plain. This earth fissure represent a potential threat to the groundwater that sustains growth in new downtown area of Beijing. An integrated survey program, including InSAR, hydrogeophysic survey and trenching, has been condected to investigate the formation and extent of the fissure. This work has allowed us to understand the processes and characterize earth fissure. InSAR result indicate the fissure in subsidence profiles occur near the part of the profile where its curvature is greatest and it is convex upward. The trenches demonstrated that the physical characteristics of this earth fissure isn't typical of similar fissures that formed in Northwest sites as a result of neotectonic activity. The ERT results across the fault suggest that the fault doesn't cut througth the whole quaternary strata and subsurface fault-associated depth was restricted to 27-43m. The occurrence and the development of the earth fissure closely parallel the pre-existing Medio-Pleistocene fault (Nanyuan-Tongxian fault) and initiated in the fault zone close to the footwall. The fissure originates within the unsaturated clayed strata at a relatively shallow depth and show a tensile failure with negligible vertical offset. The results of hydrogeophysical method and trench indicate that it migrates downward and terminate near the saturated-unsaturated interface. The survey results suggest the tensile-induced fissure was mainly caused by groundwater-level decline rather than natural tectonism.

  20. Methods for monitoring land subsidence and earth fissures in the Western USA

    NASA Astrophysics Data System (ADS)

    Fergason, K. C.; Rucker, M. L.; Panda, B. B.

    2015-11-01

    Depletion of groundwater resources in many deep alluvial basin aquifers in the Western USA is causing land subsidence, as it does in many regions worldwide. Land subsidence can severely and adversely impact infrastructure by changing the ground elevation, ground slope (grade) and through the development of ground cracks known as earth fissures that can erode into large gullies. Earth fissures have the potential to compromise the foundations of dams, levees, and other infrastructure and cause failure. Subsequent to an evaluation of the overall subsidence experienced in the vicinity of subsidence-impacted infrastructure, a detailed investigation to search for earth fissures, and design and/or mitigation of potentially effected infrastructure, a focused monitoring system should be designed and implemented. Its purpose is to provide data, and ultimately knowledge, to reduce the potential adverse impacts of land subsidence and earth fissure development to the pertinent infrastructure. This risk reduction is realized by quantifying the rate and distribution of ground deformation, and to detect ground rupture if it occurs, in the vicinity of the infrastructure. The authors have successfully designed and implemented monitoring systems capable of quantifying rates and distributions of ground subsidence and detection of ground rupture at multiple locations throughout the Western USA for several types of infrastructure including dams, levees, channels, basins, roadways, and mining facilities. Effective subsidence and earth fissure monitoring requires understanding and quantification of historic subsidence, estimation of potential future subsidence, delineation of the risk for earth fissures that could impact infrastructure, and motivation and resources to continue monitoring through time. A successful monitoring system provides the means to measure ground deformation, grade changes, displacement, and anticipate and assess the potential for earth fissuring. Employing multiple

  1. Vented Chill / No-Vent Fill of Cryogenic Propellant Tanks

    NASA Technical Reports Server (NTRS)

    Rhys, Noah O.; Foster, Lee W.; Martin, Adam K.; Stephens, Jonathan R.

    2016-01-01

    Architectures for extended duration missions often include an on-orbit replenishment of the space vehicle's cryogenic liquid propellants. Such a replenishment could be accomplished via a tank-to-tank transfer from a dedicated tanker or a more permanent propellant depot storage tank. Minimizing the propellant loss associated with transfer line and receiver propellant tank thermal conditioning is essential for mass savings. A new methodology for conducting tank-to-tank transfer while minimizing such losses has been demonstrated. Charge-Hold-Vent is the traditional methodology for conducting a tank-to-tank propellant transfer. A small amount of cryogenic liquid is introduced to chill the transfer line and propellant tank. As the propellant absorbs heat and undergoes a phase change, the tank internal pressure increases. The tank is then vented to relieve pressure prior to another charge of cryogenic liquid being introduced. This cycle is repeated until the transfer lines and tank are sufficiently chilled and the replenishment of the propellant tank is complete. This method suffers inefficiencies due to multiple chill and vent cycles within the transfer lines and associated feed system components. Additionally, this system requires precise measuring of cryogenic fluid delivery for each transfer, multiple valve cycling events, and other complexities associated with cycled operations. To minimize propellant loss and greatly simplify on-orbit operations, an alternate methodology has been designed and demonstrated. The Vented Chill / No Vent Fill method is a simpler, constant flow approach in which the propellant tank and transfer lines are only chilled once. The receiver tank is continuously vented as cryogenic liquid chills the transfer lines, tank mass and ullage space. Once chilled sufficiently, the receiver tank valve is closed and the tank is completely filled. Interestingly, the vent valve can be closed prior to receiver tank components reaching liquid saturation

  2. [Treatment of anal fissures with botulinum toxin].

    PubMed

    Wollina, U

    2008-04-01

    Chronic anal fissure is a common proctological disease. Botulinum toxin (BTX) can be used for temporary chemical denervation. The administration is by intramuscular injections into either the external or the internal anal sphincter muscles. The mode of action, administration techniques and possible complications or adverse effects of BTX therapy are discussed. The healing rate is dependent on the BTX dosage. The short-term healing rate (< or = 6 months) is between 60 and 90 %. In long-term follow-up studies (> 1 year), about 50 % of patients show a complete response. Adverse effects are generally mild but relapses occur more often compared to surgery. Conservative therapies including BTX are currently considered mostly as the first-line treatment. Among the surgical procedures, lateral sphincterotomy is the most effective treatment but shows higher incontinence and general morbidity rates than BTX.

  3. Characterization of Six Vent Fields Within the Lau Basin

    NASA Astrophysics Data System (ADS)

    Tivey, M. K.; Craddock, P.; Seewald, J.; Ferrini, V.; Kim, S.; Mottl, M.; Sterling, N. A.; Reysenbach, A.; Wheat, C. G.

    2005-12-01

    Six active vent fields on the Valu Fa Ridge and Eastern Lau Spreading Center were successfully characterized on R/V Melville cruise TUIM05MV. The Kilo Moana (20deg3.2'S), Tow Cam (20deg19'S), and ABE (20deg45.6-46'S) vent fields were first noted during two R/V Kilo Moana cruises (in April (F. Martinez, Chief Scientist) and Sept (C. Langmuir, Chief Scientist) 2004). A fourth vent field, Mariner at 22deg10.8'S, was located Sept 2004 during the Shinkai 6500 program (K. Takai, Chief Scientist) using data from previous cruises. The fifth vent field examined was the Vai Lili vent field at 22deg12.95'S (Fouquet et al., 1991, Nature 349). On the TUIM05MV cruise, a sixth large active vent field was found at 21deg59.4'S using Jason2 and data from multiple CTD tow-yos, following up on plume observations provided by the Martinez et al. cruise. Tasks conducted to characterize each vent field included 1) detailed SM2000 bathymetric surveys; 2) down-looking and/or forward-looking camera surveys to create photomosaics of megafauna distributions; 3) recovery of biological, rock (basalt and sulfide), and fluid samples, and microbiological sampling of sulfide and diffuse fluid samples; 4) MOCNESS tows to recover larval plankton from plumes; 5) CTD casts to collect plume particles. At the Kilo Moana, Tow Cam, ABE and Tui Malila vent fields, hydrothermal activity occurs in proximity to major faults. At Kilo Moana, active venting occurs in three areas from ~5m tall, branched structures as focused, high temperature flow (to 333C) through chalcopyrite (Cp)- and/or wurtzite (Zn)- lined conduits and as diffuse flow through beehive-type structures. At Tow Cam high temperature (to 330C) active venting occurs in two areas at the base of a western fault from Cp- and/or Zn-lined conduits; diffuse flow exits basalt east of the black smoker areas. Within the ABE vent field there are three large areas of active venting spaced 150 to 300 m apart along NNE trending faults and benches; fluid exits

  4. A study of suppurative pathologies associated with chronic anal fissures.

    PubMed

    Gupta, P J

    2005-07-01

    Suppurative pathologies associated with chronic anal fissures are common but not well documented. Fissure abscess, post-fissure fistula, and post-fissure antibioma are but a few of them. These pathologies increase the complications and morbidity of the primary lesion and need a comprehensive approach. From the hospital case record of 532 patients treated for chronic anal fissures, 88 patients (16.5%) were found to have one of these pathologies. This retrospective study describes such pathologies in terms of demographics, clinical presentation, pathological features, operative technique and outcome. Of the 88 patients who presented with pain and discharge per anus, 90% could resume their duties within a week of the surgical procedure. Wound healing took between 2 weeks and 2 months. At the last follow- up at 18 months, three patients had a recurrence (3.4%). Suppuration in chronic anal fissure seems to be more frequent than described. While dealing with the anal fissure, it is desirable to look for and attend to these associated pathologies, especially to avoid complications and morbidity of the primary disease.

  5. Modern perspectives in the treatment of chronic anal fissures.

    PubMed

    Bhardwaj, R; Parker, M C

    2007-07-01

    Anal fissures are commonly encountered in routine colorectal practice. Developments in the pharmacological understanding of the internal anal sphincter have resulted in more conservative approaches towards treatment. Simple measures are often effective for early fissures. Glyceryl trinitrate is well established as a first-line pharmacological therapy. The roles of diltiazem and botulinum, particularly as rescue therapy, are not well understood. Surgery has a defined role and should not be discounted completely. Data were obtained from Medline publications citing 'anal fissure'. Manual cross-referencing of salient articles was conducted. We have sought to highlight various controversies in the management of anal fissures. Acute fissures may heal spontaneously, although simple conservative measures are sufficient. Idiopathic chronic anal fissures need careful evaluation to decide what therapy is suitable. Pharmacological agents such as glyceryl trinitrate (GTN), diltiazem and botulinum toxin have been subjected to most scrutiny. Though practices in the UK vary, GTN or diltiazem would be suitable as first-line therapy with botulinum toxin used as rescue treatment. Sphincterotomy is indicated for unhealed fissures; fissurectomy has been revisited and advancement flaps have a role in patients in whom sphincter division is not suitable.

  6. Gonyautoxin: new treatment for healing acute and chronic anal fissures.

    PubMed

    Garrido, Rogelio; Lagos, Nestor; Lattes, Karinna; Abedrapo, Mario; Bocic, Gunther; Cuneo, Aldo; Chiong, Hector; Jensen, Christian; Azolas, Rodrigo; Henriquez, Ana; Garcia, Carlos

    2005-02-01

    The mayor symptoms of chronic anal fissure are permanent pain, intense pain during defecation that lasts for hours, blood in the stools, and sphincter cramps. It is subsequent to formation of fibrosis infiltrate that leads to an increased anal tone with poor healing tendency. This vicious circle leads to fissure recurrence and chronicity. This study was designed to show the efficacy of gonyautoxin infiltration in healing patients with anal fissures. Gonyautoxin is a paralyzing phytotoxin produced by dinoflagellates. Fifty recruited patients received clinical examination, including proctoscopy and questionnaire to evaluate the symptoms. Anorectal manometries were performed before and after toxin injection. Doses of 100 units of gonyautoxin in a volume of 1 ml were infiltrated into both sides of the anal fissure in the internal anal sphincter. Total remission of acute and chronic anal fissures were achieved within 15 and 28 days respectively. Ninety-eight percent of the patients healed before 28 days with a mean time healing of 17.6 +/- 9 days. Only one relapsed during 14 months of follow-up. Neither fecal incontinence nor other side effects were observed. All patients showed immediate sphincter relaxation. The maximum anal resting pressures recorded after two minutes decreased to 56.2 +/- 12.5 percent of baseline. Gonyautoxin breaks the vicious circle of pain and spasm that leads to anal fissure. This study proposes gonyautoxin anal sphincter infiltration as safe and effective alternative therapeutic approach to conservative, surgical, and botulinum toxin therapies for anal fissures.

  7. Effect of air abrasion and polishing on primary molar fissures.

    PubMed

    Lenzi, T L; Menezes, L B R; Soares, F Z M; Rocha, R O

    2013-04-01

    To evaluate the effect of air abrasion and polishing on primary molar fissures under light microscopy. 15 exfoliated primary second molars were longitudinally sectioned and photographed under a stereomicroscope (40×; baseline evaluation). Sections were then randomly allocated into one of the two groups (n = 15) and treated by either air abrasion (aluminium oxide jet) or air polishing (sodium bicarbonate jet) for 30 s. After treatment, sections were washed with an air/water spray, dried with absorbent paper, and photographed as previously described (final evaluation). Baseline and final morphology were compared by two blinded examiners who evaluated changes in the width and depth of fissures. The percentage of changed fissures was analysed, and the two treatments were compared using the Mann-Whitney test (α = 0.01). Both air systems resulted in fissure changes in most (93.3 %) of the sections. No significant differences in fissure width changes were found between treatments, but when changes in fissure depth were evaluated, air polishing was found to be less damaging than air abrasion (p < 0.01). Air abrasion and polishing cause changes to the anatomical configuration of occlusal fissures of primary molars.

  8. Electricity generation from hydrothermal vents

    NASA Astrophysics Data System (ADS)

    Aryadi, Y.; Rizal, I. S.; Fadhli, M. N.

    2016-09-01

    Hydrothermal vent is a kind of manifestation of geothermal energy on seabed. It produces high temperature fluid through a hole which has a diameter in various range between several inches to tens of meters. Hydrothermal vent is mostly found over ocean ridges. There are some 67000 km of ocean ridges, 13000 of them have been already studied discovering more than 280 sites with geothermal vents. Some of them have a thermal power of up to 60 MWt. These big potential resources of energy, which are located over subsea, have a constraint related to environmental impact to the biotas live around when it becomes an object of exploitation. Organic Rankine Cycle (ORC) is a method of exploiting heat energy to become electricity using organic fluid. This paper presents a model of exploitation technology of hydrothermal vent using ORC method. With conservative calculation, it can give result of 15 MWe by exploiting a middle range diameter of hydrothermal vent in deep of 2000 meters below sea level. The technology provided here really has small impact to the environment. With an output energy as huge as mentioned before, the price of constructing this technology is low considering the empty of cost for drilling as what it should be in conventional exploitation. This paper also presents the comparison in several equipment which is more suitable to be installed over subsea.

  9. Understanding the environmental impacts of large fissure eruptions: Aerosol and gas emissions from the 2014-2015 Holuhraun eruption (Iceland)

    NASA Astrophysics Data System (ADS)

    Ilyinskaya, Evgenia; Schmidt, Anja; Mather, Tamsin A.; Pope, Francis D.; Witham, Claire; Baxter, Peter; Jóhannsson, Thorsteinn; Pfeffer, Melissa; Barsotti, Sara; Singh, Ajit; Sanderson, Paul; Bergsson, Baldur; McCormick Kilbride, Brendan; Donovan, Amy; Peters, Nial; Oppenheimer, Clive; Edmonds, Marie

    2017-08-01

    The 2014-2015 Holuhraun eruption in Iceland, emitted ∼11 Tg of SO2 into the troposphere over 6 months, and caused one of the most intense and widespread volcanogenic air pollution events in centuries. This study provides a number of source terms for characterisation of plumes in large fissure eruptions, in Iceland and elsewhere. We characterised the chemistry of aerosol particle matter (PM) and gas in the Holuhraun plume, and its evolution as the plume dispersed, both via measurements and modelling. The plume was sampled at the eruptive vent, and in two populated areas in Iceland. The plume caused repeated air pollution events, exceeding hourly air quality standards (350 μg/m3) for SO2 on 88 occasions in Reykjahlíð town (100 km distance), and 34 occasions in Reykjavík capital area (250 km distance). Average daily concentration of volcanogenic PM sulphate exceeded 5 μg/m3 on 30 days in Reykjavík capital area, which is the maximum concentration measured during non-eruptive background interval. There are currently no established air quality standards for sulphate. Combining the results from direct sampling and dispersion modelling, we identified two types of plume impacting the downwind populated areas. The first type was characterised by high concentrations of both SO2 and S-bearing PM, with a high Sgas/SPM mass ratio (SO2(g)/SO42-(PM) > 10). The second type had a low Sgas/SPM ratio (<10). We suggest that this second type was a mature plume where sulphur had undergone significant gas-to-aerosol conversion in the atmosphere. Both types of plume were rich in fine aerosol (predominantly PM1 and PM2.5), sulphate (on average ∼90% of the PM mass) and various trace species, including heavy metals. The fine size of the volcanic PM mass (75-80% in PM2.5), and the high environmental lability of its chemical components have potential adverse implications for environmental and health impacts. However, only the dispersion of volcanic SO2 was forecast in public warnings

  10. 2D models of gas flow and ice grain acceleration in Enceladus' vents using DSMC methods

    NASA Astrophysics Data System (ADS)

    Tucker, Orenthal J.; Combi, Michael R.; Tenishev, Valeriy M.

    2015-09-01

    The gas distribution of the Enceladus water vapor plume and the terminal speeds of ejected ice grains are physically linked to its subsurface fissures and vents. It is estimated that the gas exits the fissures with speeds of ∼300-1000 m/s, while the micron-sized grains are ejected with speeds comparable to the escape speed (Schmidt, J. et al. [2008]. Nature 451, 685-688). We investigated the effects of isolated axisymmetric vent geometries on subsurface gas distributions, and in turn, the effects of gas drag on grain acceleration. Subsurface gas flows were modeled using a collision-limiter Direct Simulation Monte Carlo (DSMC) technique in order to consider a broad range of flow regimes (Bird, G. [1994]. Molecular Gas Dynamics and the Direct Simulation of Gas Flows. Oxford University Press, Oxford; Titov, E.V. et al. [2008]. J. Propul. Power 24(2), 311-321). The resulting DSMC gas distributions were used to determine the drag force for the integration of ice grain trajectories in a test particle model. Simulations were performed for diffuse flows in wide channels (Reynolds number ∼10-250) and dense flows in narrow tubular channels (Reynolds number ∼106). We compared gas properties like bulk speed and temperature, and the terminal grain speeds obtained at the vent exit with inferred values for the plume from Cassini data. In the simulations of wide fissures with dimensions similar to that of the Tiger Stripes the resulting subsurface gas densities of ∼1014-1020 m-3 were not sufficient to accelerate even micron-sized ice grains to the Enceladus escape speed. In the simulations of narrow tubular vents with radii of ∼10 m, the much denser flows with number densities of 1021-1023 m-3 accelerated micron-sized grains to bulk gas speed of ∼600 m/s. Further investigations are required to understand the complex relationship between the vent geometry, gas source rate and the sizes and speeds of ejected grains.

  11. The History of Venting (part I)

    NASA Technical Reports Server (NTRS)

    Leiter, Stephen C.

    2017-01-01

    Venting techniques and design are an important implementation strategy for observatory and payload contamination control, and yet venting analysis has seen a topsey turvey history, at lease from the perspective of the simple Layman trying to design a black box. Additionally, designing the vent has competing controls from Safety and EMIEMC. In the days of Shuttle, Safety placed liens against the vents of blankets, boxes, and large structural items principally to protect cargo bay vents but also from a flammability perspective. What continues to elude the Designer Community is a stable, simple way of designing vents for black boxes that satisfies everybody. But we continue to try.

  12. Assessing future vent opening locations at the Somma-Vesuvio volcanic complex: 1. A new information geodatabase with uncertainty characterizations

    NASA Astrophysics Data System (ADS)

    Tadini, A.; Bisson, M.; Neri, A.; Cioni, R.; Bevilacqua, A.; Aspinall, W. P.

    2017-06-01

    This study presents new and revised data sets about the spatial distribution of past volcanic vents, eruptive fissures, and regional/local structures of the Somma-Vesuvio volcanic system (Italy). The innovative features of the study are the identification and quantification of important sources of uncertainty affecting interpretations of the data sets. In this regard, the spatial uncertainty of each feature is modeled by an uncertainty area, i.e., a geometric element typically represented by a polygon drawn around points or lines. The new data sets have been assembled as an updatable geodatabase that integrates and complements existing databases for Somma-Vesuvio. The data are organized into 4 data sets and stored as 11 feature classes (points and lines for feature locations and polygons for the associated uncertainty areas), totaling more than 1700 elements. More specifically, volcanic vent and eruptive fissure elements are subdivided into feature classes according to their associated eruptive styles: (i) Plinian and sub-Plinian eruptions (i.e., large- or medium-scale explosive activity); (ii) violent Strombolian and continuous ash emission eruptions (i.e., small-scale explosive activity); and (iii) effusive eruptions (including eruptions from both parasitic vents and eruptive fissures). Regional and local structures (i.e., deep faults) are represented as linear feature classes. To support interpretation of the eruption data, additional data sets are provided for Somma-Vesuvio geological units and caldera morphological features. In the companion paper, the data presented here, and the associated uncertainties, are used to develop a first vent opening probability map for the Somma-Vesuvio caldera, with specific attention focused on large or medium explosive events.

  13. High-Resolution Micro-Bathymetry Mapping in the Lau Basin: Examples From the Tui Malila and Mariner Vent Sites

    NASA Astrophysics Data System (ADS)

    Ferrini, V.; Sterling, A.; Martinez, F.; Tivey, M. K.; Mottl, M.; Kim, S.

    2005-12-01

    High-resolution SM2000 (200 kHz) multibeam sonar data were collected at six vent areas on the Lau Basin spreading center in April 2005. Data were acquired during near-bottom surveys conducted with the ROV Jason II at altitudes ranging from 5 to 20 m. High altitude (20 m) bathymetric surveys were complemented by near-bottom visual surveys, which provided ground-truth observations of the seafloor. Combined with Doppler and Long Baseline (LBL) Navigation, these bathymetry data provide sub-meter resolution of seafloor features, and reveal individual vent structures, faults and fissures. We present bathymetry data from two sites located 22 km apart, which are geologically and biologically distinct and exhibit contrasts in venting styles and biota. The Mariner vent field contains massive vent structures, many of which are taller than 25 m, with active venting from their bases and sides. Fluids exit as vigorous, high-temperature (< 363°C) black smoker fluids through chalcopyrite-lined conduits, and as less focused flow from porous beehive structures. Inactive structures are friable and are composed of iron- and copper-oxides. There was little evidence of faulting or fracture at the vent field, but we note the presence of collapsed volcanic dome structures. The vent fauna at Mariner is very limited; only Bythograeid and Galatheid crabs, and one Brisingid Seastar, were found. Tui Malila, by contrast, is characterized by shorter and wider branched vent structures with coalesced spires, the tops of which were actively venting. There is extensive faulting and fracture at this site, as well as a number of large flanges and areas of diffuse flow. At Tui Malila fluids exit tall structures through chalcopyrite- and zinc-lined conduits (at temperatures < 312°C), from beneath flanges, and directly from andesite. Hydrothermal breccias are also present. Tui Malila hosts a more typical vent community, with greater abundances of both Bythograeid and Galatheid crabs, mostly within 4 m

  14. Reactor pressure vessel vented head

    DOEpatents

    Sawabe, James K.

    1994-01-11

    A head for closing a nuclear reactor pressure vessel shell includes an arcuate dome having an integral head flange which includes a mating surface for sealingly mating with the shell upon assembly therewith. The head flange includes an internal passage extending therethrough with a first port being disposed on the head mating surface. A vent line includes a proximal end disposed in flow communication with the head internal passage, and a distal end disposed in flow communication with the inside of the dome for channeling a fluid therethrough. The vent line is fixedly joined to the dome and is carried therewith when the head is assembled to and disassembled from the shell.

  15. Modeling of zero gravity venting

    NASA Technical Reports Server (NTRS)

    Merte, H., Jr.

    1984-01-01

    The venting of cylindrical containers partially filled with initially saturated liquids was conducted under zero gravity conditions and compared with an analytical model which determined the effect of interfacial mass transfer on the ullage pressure response during venting. A model is proposed to improve the estimation of the interfacial mass transfer. Duhammel's superposition integral is incorporated in this analysis to approximate the transient temperature response of the interface, treating the liquid as a semiinfinite solid with conduction heat transfer. This approach to estimating interfacial mass transfer gives improved response when compared to previous models. The model still predicts a pressure decrease greater than those in the experiments reported.

  16. Prevalence of incomplete interlobar fissures of the lung.

    PubMed

    Sedlackova, Zuzana; Ctvrtlik, Filip; Miroslav, Herman

    2016-12-01

    Some patients benefit from accurate integrity assessment of pulmonary fissures. There are a number of methods for the assessment of incomplete interlobar fissures: imaging techniques, endobronchial methods measuring collateral air flow, a perioperative view, and autopsies used in research into pulmonary anatomy. We performed a computerized advanced search for primary evidence in the PubMed (Public/Publisher MEDLINE) and Google Scholar electronic databases using the following terms: incomplete and fissure. The search was not restricted to the English literature, nor limited by publication time. The bibliographic search was then extended to the "Related Articles" links and to the list of literature references of each article. Publications have consistently shown that interlobar fissures exhibit high variability and that preoperative or at least detailed perioperative assessment can influence the effect of treatment.

  17. Implications of ground-deformation measurements across earth fissures in subsidence areas in the southwestern USA

    USGS Publications Warehouse

    Holzer, Thomas L.

    2010-01-01

    Ground deformation was monitored at earth fissures in areas of land subsidence induced by groundwater extraction in the southwestern United States. The ground deformation is consistent with the mechanism that fissures are caused by horizontal strains generated by bending of overburden in response to localized differential compaction. Subsidence profiles indicated that localized differential subsidence occurred across the fissures and that maximum convex-upward curvature was at the fissure. The overall shape of the profile stayed similar with time, and maximum curvature remained stationary at the fissure. Horizontal displacements were largest near the fissure, and generally were small to negligible away from the fissure. Maximum tensile horizontal strains were at the fissure and coincided with maximum curvature in the subsidence profiles. Horizontal tensile strain continued to accumulate at fissures after they formed with rates of opening ranging from 30 to 120 microstrain/year at fissures in Arizona.

  18. Hardness testing of some fissure-sealing materials.

    PubMed

    Ulvestad, H

    1977-11-01

    The mechanical properties of fissure-sealing materials are of significant importance for their durability, i.e. their wear resistance. One of the methods of evaluating a material's resistance to attrition is to apply a hardness test. In the present investigation, the surface hardness of some fissure-sealing materials was tested. Sealants made from diluted composite materials and with inclusion of inorganic filler particles appeared to have a considerable higher surface hardness than the other sealing materials tested.

  19. Differential compaction mechanism for earth fissures near Casa Grande, Arizona.

    USGS Publications Warehouse

    Jachens, R.C.; Holzer, T.L.

    1982-01-01

    Precise gravity measurements indicate that earth fissures or tension cracks caused by ground-water withdrawal within a 10km2 area SE of Casa Grande are associated with relief on the buried interface between the alluvial aquifer and underlying bedrock. These relations suggest that the fissures are forming in response to localized differential compaction caused by localized variations of aquifer-system thickness. -from Authors

  20. Fill and vent quick disconnect

    NASA Technical Reports Server (NTRS)

    Boerner, R. Y.; Hedrick, R. W.

    1972-01-01

    Hydraulic disconnect coupling on ground serving half of spacecraft refrigeration cooling system employs movable center stem for venting and closing nipple poppet. Self sealing poppet quickly connects cooling system to spacecraft without manual work. Recessed sealing surface insures open poppet when stem retracts.

  1. Transperineal sonographic anal sphincter complex evaluation in chronic anal fissures.

    PubMed

    Bedair, Elsaid M; El Hennawy, Hany M; Moustafa, Ahmed Abdu; Meki, Gad Youssef; Bosat, Bosat Elwany

    2014-11-01

    The purpose of this study was to assess the role of transperineal sonography in assessment of pathologic changes to the anal sphincter complex in patients with chronic anal fissures. We conducted a prospective case-control study of 100 consecutive patients of any age and both sexes with chronic anal fissures who presented to a colorectal clinic between January 2012 and August 2013 (group A) and 50 healthy volunteers (group B). The most common patterns of radiologic changes to anal sphincters associated with chronic anal fissures were circumferential thickening of the anal sphincter complex in 5 patients (5%), circumferential thickening of the internal anal sphincter in 3 patients (3%), preferential thickening of the internal anal sphincter at the 6-o'clock position in 80 patients (80%) and the 12-o'clock position in 7 patients (7%), preferential thickening of the internal and external anal sphincters in 3 patients (3%), and thinning of the internal anal sphincter in 2 patients (2%). Chronic anal fissures cause differential thickening of both internal and external anal sphincters, with a trend toward increased thickness in relation to the site of the fissure. Routine preoperative transperineal sonography for patients with chronic anal fissures is recommended, and it is mandatory in high-risk patients. © 2014 by the American Institute of Ultrasound in Medicine.

  2. Modern Perspectives in the Treatment of Chronic Anal Fissures

    PubMed Central

    Bhardwaj, R; Parker, MC

    2007-01-01

    INTRODUCTION Anal fissures are commonly encountered in routine colorectal practice. Developments in the pharmacological understanding of the internal anal sphincter have resulted in more conservative approaches towards treatment. Simple measures are often effective for early fissures. Glyceryl trinitrate is well established as a first-line pharmacological therapy. The roles of diltiazem and botulinum, particularly as rescue therapy, are not well understood. Surgery has a defined role and should not be discounted completely. METHODS Data were obtained from Medline publications citing ‘anal fissure’. Manual cross-referencing of salient articles was conducted. We have sought to highlight various controversies in the management of anal fissures. FINDINGS Acute fissures may heal spontaneously, although simple conservative measures are sufficient. Idiopathic chronic anal fissures need careful evaluation to decide what therapy is suitable. Pharmacological agents such as glyceryl trinitrate (GTN), diltiazem and botulinum toxin have been subjected to most scrutiny. Though practices in the UK vary, GTN or diltiazem would be suitable as first-line therapy with botulinum toxin used as rescue treatment. Sphincterotomy is indicated for unhealed fissures; fissurectomy has been revisited and advancement flaps have a role in patients in whom sphincter division is not suitable. PMID:17688717

  3. Randomized trial on fluorides and sealants for fissure caries prevention.

    PubMed

    Liu, B Y; Lo, E C M; Chu, C H; Lin, H C

    2012-08-01

    To investigate the effectiveness of topical fluorides in preventing fissure caries, we conducted a randomized controlled trial with parallel groups. In total, 501 children (1,539 molars, 3,078 sites), mean age 9.1 years, who had at least one sound permanent first molar with deep fissures or fissures with signs of early caries were recruited. They were randomly allocated among four groups: (1) resin sealant, single placement; (2) 5% NaF varnish, semi-annual application; (3) 38% silver diamine fluoride (SDF) solution, annual application; and (4) placebo control. Follow-up examinations were conducted every 6 months by a masked examiner. After 24 months, 485 children (97%) were examined. Proportions of pit/fissure sites with dentin caries in the sealant, NaF, SDF, and control groups were 1.6%, 2.4%, 2.2%, and 4.6%, respectively. A multi-level logistic regression analysis accounting for the effects of data clustering and confounding factors showed that fissures in any of the three treatment groups had significantly lower risks of carious cavity development into dentin than did controls (p < 0.05). We concluded that placement of resin sealant, semi-annual application of NaF varnish, and annual application of SDF solution are all effective in preventing pit and fissure caries in permanent molars (ClinicalTrials.gov number CT01446107).

  4. Diffuse versus discrete venting at the Tour Eiffel vent site, Lucky Strike hydrothermal field

    NASA Astrophysics Data System (ADS)

    Mittelstaedt, E. L.; Escartin, J.; Gracias, N.; Olive, J. L.; Barreyre, T.; Davaille, A. B.; Cannat, M.

    2010-12-01

    Two styles of fluid flow at the seafloor are widely recognized: (1) localized outflows of high temperature (>300°C) fluids, often black or grey color in color (“black smokers”) and (2) diffuse, lower temperature (<100°C), fluids typically transparent and which escape through fractures, porous rock, and sediment. The partitioning of heat flux between these two types of hydrothermal venting is debated and estimates of the proportion of heat carried by diffuse flow at ridge axes range from 20% to 90% of the total axial heat flux. Here, we attempt to improve estimates of this partitioning by carefully characterizing the heat fluxes carried by diffuse and discrete flows at a single vent site, Tour Eiffel in the Lucky Strike hydrothermal field along the Mid-Atlantic Ridge. Fluid temperature and video data were acquired during the recent Bathyluck’09 cruise to the Lucky Strike hydrothermal field (September, 2009) by Victor aboard “Pourquoi Pas?” (IFREMER, France). Temperature measurements were made of fluid exiting discrete vents, of diffuse effluents immediately above the seafloor, and of vertical temperature gradients within discrete hydrothermal plumes. Video data allow us to calculate the fluid velocity field associated with these outflows: for diffuse fluids, Diffuse Flow Velocimetry tracks the displacement of refractive index anomalies through time; for individual hydrothermal plumes, Particle Image Velocimetry tracks eddies by cross-correlation of pixels intensities between subsequent images. Diffuse fluids exhibit temperatures of 8-60°C and fluid velocities of ~1-10 cm s-1. Discrete outflows at 204-300°C have velocities of ~1-2 m s-1. Combined fluid flow velocities, temperature measurements, and full image mosaics of the actively venting areas are used to estimate heat flux of both individual discrete vents and diffuse outflow. The total integrated heat flux and the partitioning between diffuse and discrete venting at Tour Eiffel, and its

  5. 46 CFR 151.15-5 - Venting.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Venting. 151.15-5 Section 151.15-5 Shipping COAST GUARD...) Pressure-vacuum venting. A normally closed venting system fitted with a device to automatically limit the pressure or vacuum in the tank to design limits. Pressure-vacuum relief valves shall comply with...

  6. Preoperational test, vent building ventilation system

    SciTech Connect

    Clifton, F.T., Westinghouse Hanford

    1996-08-20

    Preoperational Test Procedure for Vent Building Ventilation System, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The Vent Building ventilation system provides ventilation, heating, cooling, and zone confinement control for the W-030 Project Vent Building. The tests verify correct System operation and correct indications displayed by the central Monitor and Control system.

  7. 33 CFR 159.61 - Vents.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Vents. 159.61 Section 159.61 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION MARINE SANITATION DEVICES Design, Construction, and Testing § 159.61 Vents. Vents must be designed and...

  8. 33 CFR 159.61 - Vents.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Vents. 159.61 Section 159.61 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION MARINE SANITATION DEVICES Design, Construction, and Testing § 159.61 Vents. Vents must be designed and...

  9. 33 CFR 159.61 - Vents.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Vents. 159.61 Section 159.61 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION MARINE SANITATION DEVICES Design, Construction, and Testing § 159.61 Vents. Vents must be designed and...

  10. 33 CFR 159.61 - Vents.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Vents. 159.61 Section 159.61 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION MARINE SANITATION DEVICES Design, Construction, and Testing § 159.61 Vents. Vents must be designed and...

  11. 33 CFR 159.61 - Vents.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Vents. 159.61 Section 159.61 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION MARINE SANITATION DEVICES Design, Construction, and Testing § 159.61 Vents. Vents must be designed and...

  12. Patterns of Lava Morphology and Fissures along the Galapagos Spreading Center 89.5º - 95º W by Automated Classification of Side-scan Sonar Imagery

    NASA Astrophysics Data System (ADS)

    Meyer, J. D.; White, S. M.

    2006-12-01

    the GSC is most affected by the hotspot. The abundance of fissures or sheet/lobate flows prove to be poor predictors of the location of high-temperature hydrothermal vents on a regional scale. This supports the view that magma supply is the primary control on black smoker vents on the GSC.

  13. Complete genome sequence of the thermophilic sulfur-reducer Desulfurobacterium thermolithotrophum type strain (BSAT) from a deep-sea hydrothermal vent

    SciTech Connect

    Goker, Markus; Daligault, Hajnalka E.; Mwirichia, Romano; Lapidus, Alla L.; Deshpande, Shweta; Pagani, Ioanna; Tapia, Roxanne; Cheng, Jan-Fang; Goodwin, Lynne A.; Pitluck, Sam; Liolios, Konstantinos; Ivanova, N; Mavromatis, K; Mikhailova, Natalia; Pati, Amrita; Chen, Amy; Palaniappan, Krishna; Han, Cliff; Land, Miriam L; Hauser, Loren John; Pan, Chongle; Brambilla, Evelyne-Marie; Rohde, Manfred; Spring, Stefan; Sikorski, Johannes; Wirth, Reinhard; Detter, J. Chris; Woyke, Tanja; Bristow, James; Eisen, Jonathan; Markowitz, Victor; Hugenholtz, Philip; Kyrpides, Nikos C; Klenk, Hans-Peter

    2011-01-01

    Desulfurobacterium thermolithotrophum L'Haridon et al. 1998 is the type species of the ge- nus Desulfurobacterium which belongs to the family Desulfurobacteriaceae. The species is of interest because it represents the first thermophilic bacterium that can act as a primary pro- ducer in the temperature range of 45-75 C (optimum 70 C) and is incapable of growing un- der microaerophilic conditions. Strain BSAT preferentially synthesizes high-melting-point fatty acids (C18 and C20) which is hypothesized to be a strategy to ensure the functionality of the membrane at high growth temperatures. This is the second completed genome sequence of a member of the family Desulfurobacteriaceae and the first sequence from the genus Desulfu- robacterium. The 1,541,968 bp long genome harbors 1,543 protein-coding and 51 RNA genes and is a part of the Genomic Encyclopedia of Bacteria and Archaea project.

  14. Pulmonary Fissure Integrity and Collateral Ventilation in COPD Patients

    PubMed Central

    Pu, Jiantao; Wang, Zhimin; Gu, Suicheng; Fuhrman, Carl; Leader, Joseph K.; Meng, Xin; Tedrow, John; Sciurba, Frank C.

    2014-01-01

    Purpose To investigate whether the integrity (completeness) of pulmonary fissures affects pulmonary function in patients with chronic obstructive pulmonary disease (COPD). Materials and Methods A dataset consisting of 573 CT exams acquired on different subjects was collected from a COPD study. According to the global initiative for chronic obstructive lung disease (GOLD) criteria, these subjects (examinations) were classified into five different subgroups, namely non-COPD (222 subjects), GOLD-I (83 subjects), GOLD-II (141 subjects), GOLD-III (63 subjects), and GOLD-IV (64 subjects), in terms of disease severity. An available computer tool was used to aid in an objective and efficient quantification of fissure integrity. The correlations between fissure integrity, and pulmonary functions (e.g., FEV1, and FEV1/FVC) and COPD severity were assessed using Pearson and Spearman's correlation coefficients, respectively. Results For the five sub-groups ranging from non-COPD to GOLD-IV, the average integrities of the right oblique fissure (ROF) were 81.8%, 82.4%, 81.8%, 82.8%, and 80.2%, respectively; the average integrities of the right horizontal fissure (RHF) were 62.6%, 61.8%, 62.1%, 62.2%, and 62.3%, respectively; the average integrities of the left oblique fissure (LOF) were 82.0%, 83.2%, 81.7%, 82.0%, and 78.4%, respectively; and the average integrities of all fissures in the entire lung were 78.0%, 78.6%, 78.1%, 78.5%, and 76.4%, respectively. Their Pearson correlation coefficients with FEV1 and FE1/FVC range from 0.027 to 0.248 with p values larger than 0.05. Their Spearman correlation coefficients with COPD severity except GOLD-IV range from −0.013 to −0.073 with p values larger than 0.08. Conclusion There is no significant difference in fissure integrity for patients with different levels of disease severity, suggesting that the development of COPD does not change the completeness of pulmonary fissures and incomplete fissures alone may not contribute to the

  15. Drivers of explosivity and elevated hazard in basaltic fissure eruptions: The 1913 eruption of Ambrym Volcano, Vanuatu (SW-Pacific)

    NASA Astrophysics Data System (ADS)

    Németh, Károly; Cronin, Shane J.

    2011-04-01

    Fissure-eruptions along linear structures can extend for several tens of kilometres with distinct separate manifestations of volcanism along their length. They typically involve low-viscosity mafic magmas forming long lava flows and cinder cones. Eruptions in 1894 and 1913 on Ambrym volcano, Vanuatu, showed how these mildly explosive eruptions can rapidly transform into violent explosive events, producing significant hazard and widespread volcanic ash clouds. During the 1913 episode, a fissure began in the central caldera and basaltic magmas broke out in a series of locations down the island's western flank. In all sites over 100 m in elevation, fissure outbreaks produced vigorous lava fountains and highly fluid lava flows that travelled rapidly to the shoreline. When the outbreaks propagated along the island's axis into coastal plain areas, a climactic series of explosive eruptions occurred, producing a 1.2 km long by 600 m wide maar and tephra ring. A further small tuff ring was formed later, creating a temporary island 400 m offshore. The onshore tephra ring destroyed a hospital and associated buildings. Its last evacuating occupants were close witnesses to the eruption processes. Deposits exposed in the lower portion of the tephra ring show that this part of the eruption began with a mild phreatomagmatic explosive eruption from a narrow vent, followed by a magmatic scoria-producing phase. Subsequently a complex sequence of highly explosive phreatomagmatic eruptions occurred, producing pyroclastic surges, along with repeated distinctive breccia-horizons, rich in coral and lava country rock. These features tally with eye-witness accounts to indicate that the main eruption phase was produced by a periodically shifting locus of phreatomagmatic fragmentation and eruption along a single E-W fissure. The glassy and vesicle-poor pyroclasts produced during this eruption phase were dominantly fragmented in a brittle manner by magma water interaction. Low volatile content

  16. DETAIL OF A TYPICAL GABLE VENT. VIEW FACING SOUTH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DETAIL OF A TYPICAL GABLE VENT. VIEW FACING SOUTH - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, U-Shaped Three-Bedroom Duplex Type 3, Acacia Road, Birch Circle, and Cedar Drive, Pearl City, Honolulu County, HI

  17. Long-term performance of resin based fissure sealants placed in a general dental practice.

    PubMed

    Hevinga, M A; Opdam, N J M; Bronkhorst, E M; Truin, G J; Huysmans, M C D N J M

    2010-01-01

    The aim of the present retrospective study was to evaluate the long-term performance of resin based fissure sealants applied in a general dental practice. Regularly attending patients visiting the practice between July 2006 until November 2007 and who had received sealants before 1st of January 2000 were included in the study. Date of placement of a sealant in posterior non-discoloured permanent teeth and replacement by a restoration was recorded. In a clinical examination occlusal surfaces were scored for (partial) sealant loss and fissure discolouration. The restoration profile of the patient was assessed as low or high, based on the number of restorations placed per year since the first sealant. Sealants had been applied by four dentists and a dental hygienist. 1204 sealants were placed in 148 patients. After a mean follow-up time of 11.6 years, 41.3% of placed sealants were still fully retained and 11.4% were replaced by a restoration. Failure rates were significantly higher in high than in low restoration profile patients and in molars compared to premolars. In those fissures with lost or partially lost sealants, discolouration frequently occurred (40% of all surfaces) irrespective of restoration profile of the patient. In this retrospective practice based study, long-term performance of sealants depended on restoration profile of the individual patient and the tooth type (molar versus premolar).

  18. Long-term follow-up after combined fissurectomy and Botox injection for chronic anal fissures.

    PubMed

    Scholz, Th; Hetzer, F H; Dindo, D; Demartines, N; Clavien, P A; Hahnloser, D

    2007-09-01

    Chronic anal fissures are difficult to treat. The aim of this retrospective study was to determine the outcome of combined fissurectomy and injection of botulinum toxin Type A (BT). Between January 2001 and August 2004, 40 patients (21 women), median age 37 years (range 18 to 57), underwent fissurectomy and BT injection. Fissurectomy was performed followed by injection of 10 U of BT into the internal anal sphincter on both sides of the fissure. All patients were clinically checked 6 weeks after the operation. At 1 year, patients were sent a detailed questionnaire regarding symptoms, recurrence and further treatment for evaluation of long-term results. At 6 weeks, 38 patients (95%) were free of symptoms. No adverse effects were detected. The response rate of questionnaires was 93%; the median follow-up was 1 year (range 0.9 to 1.6). In the long-term, a recurrence was found in four patients. These patients were treated successfully with repeated fissurectomy and BT injections and salvage procedures, respectively. Overall, the success rate of combined fissurectomy and BT injection was 79%. Combined fissurectomy and Botox injection for chronic anal fissure is an excellent and safe procedure with low morbidity and a high healing rate.

  19. Arteries and Veins of the Sylvian Fissure and Insula: Microsurgical Anatomy.

    PubMed

    Delion, Matthieu; Mercier, Philippe; Brassier, Gilles

    2016-01-01

    We present a vascular anatomical study of the arteries and veins of the sylvian fissure and insula.A good knowledge of the sylvian fissure, the insula, and their vascular relationship would seem mandatory before performing surgery in this area, whatever the type of surgery (aneurysms, arteriovenous malformations, insular tumors).We start with the sylvian fissure and insula morphology, followed by the MCA description and its perforators, with special attention paid to the insular perforators. We demonstrate that the long insular perforators penetrating in the superior part of the posterior short gyrus and long gyri vascularize, respectively, the corticonuclear and corticospinal fasciculi. We particularly insist too on three anatomical constants regarding the vascularization of the insula, already described in the literature: The superior periinsular sulcus is the only sulcus on the lateral surface of the brain without an artery along its axis; the superior branch of the MCA supplies the anterior insular pole and both the anterior and middle short gyri in 100 % of cases; in at least 90 % of cases, the artery that supplied the central insular sulcus continued on to become the central artery.We end with the anatomical study of the veins and cisterns.

  20. Lateral internal sphincterotomy for surgically recurrent chronic anal fissure.

    PubMed

    Liang, Jennifer; Church, James M

    2015-10-01

    Lateral internal sphincterotomy cures chronic anal fissure by preventing internal sphincter hypertonia. However, cutting sphincter predisposes to sphincter dysfunction, manifests as incontinence of gas, liquid, or stool. Surgeons, therefore, can be too cautious in its use, making ineffective superficial incisions or avoiding the operation altogether. This study is designed to confirm the role of redo lateral internal sphincterotomy in the treatment of surgically recurrent chronic anal fissure. Patients undergoing repeat lateral internal sphincterotomy for surgically recurrent chronic anal fissure were accessed from a prospectively maintained database. Chronicity was defined by symptoms persisting more than 3 weeks. Contralateral sphincterotomy was performed with electrocautery through a stab incision over the intersphincteric plane. The length of sphincter division was the same as the length of the fissure. Phone questionnaire was administered and fecal continence was assessed by modified Cleveland Clinic Incontinence Score. Patients were asked to rank their overall satisfaction with the operation, and pre- and postoperative quality of life. There were 57 patients, 24 women and 33 men; mean age was 47.9 ± 14.8 years. Mean follow-up was 12.5 ± 4.2 years (range 6.2 to 25.2 years). Presenting symptoms included pain (100%), bleeding (80%), pruritus ani (39%), constipation (26%), and diarrhea. Fifty patients (90%) presented with 1 fissure, and 40 were posterior. Most procedures were performed on an outpatient basis. Fissure healing rate was 98%, and 2 patients (4%) developed minor incontinence postoperatively (one of gas, the other, gas and seepage). Overall satisfaction was 9.7 ± .9 out of 10 with a significant improvement in the quality of life from 5.7 ± 2.4 out of 10 to 9.3 ± 1.4 out of 10 (P < .001). Judicious repeat lateral sphincterotomy cures recurrent chronic fissures with minimal risk of incontinence. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Reactor pressure vessel vented head

    DOEpatents

    Sawabe, J.K.

    1994-01-11

    A head for closing a nuclear reactor pressure vessel shell includes an arcuate dome having an integral head flange which includes a mating surface for sealingly mating with the shell upon assembly therewith. The head flange includes an internal passage extending therethrough with a first port being disposed on the head mating surface. A vent line includes a proximal end disposed in flow communication with the head internal passage, and a distal end disposed in flow communication with the inside of the dome for channeling a fluid therethrough. The vent line is fixedly joined to the dome and is carried therewith when the head is assembled to and disassembled from the shell. 6 figures.

  2. Differences in recovery between deep-sea hydrothermal vent and vent-proximate communities after a volcanic eruption

    NASA Astrophysics Data System (ADS)

    Gollner, Sabine; Govenar, Breea; Arbizu, Pedro Martinez; Mills, Susan; Le Bris, Nadine; Weinbauer, Markus; Shank, Timothy M.; Bright, Monika

    2015-12-01

    Deep-sea hydrothermal vents and the surrounding basalt seafloor are subject to major natural disturbance events such as volcanic eruptions. In the near future, anthropogenic disturbance in the form of deep-sea mining could also significantly affect the faunal communities of hydrothermal vents. In this study, we monitor and compare the recovery of insular, highly productive vent communities and vent-proximate basalt communities following a volcanic eruption that destroyed almost all existing communities at the East Pacific Rise, 9°50‧N in 2006. To study the recovery patterns of the benthic communities, we placed settlement substrates at vent sites and their proximate basalt areas and measured the prokaryotic abundance and compared the meio- and macrofaunal species richness and composition at one, two and four years after the eruption. In addition, we collected samples from the overlying water column with a pelagic pump, at one and two years after the volcanic eruption, to determine the abundance of potential meiofauna colonisers. One year after eruption, mean meio- and macrofaunal abundances were not significantly different from pre-eruption values in vent habitats (meio: 8-1838 ind. 64 cm-2 in 2006; 3-6246 ind. 64 cm-2 in 2001/02; macro: 95-1600 ind. 64 cm-2 in 2006; 205-4577 ind. 64 cm-2 in 2001/02) and on non-vent basalt habitats (meio: 10-1922 ind. 64 cm-2 in 2006; 8-328 ind. 64 cm-2 in 2003/04; macro: 14-3351 ind. 64 cm-2 in 2006; 2-63 ind. 64 cm-2 in 2003/04), but species recovery patterns differed between the two habitat types. In the vent habitat, the initial community recovery was relatively quick but incomplete four years after eruption, which may be due to the good dispersal capabilities of vent endemic macrofauna and vent endemic dirivultid copepods. At vents, 42% of the pre-eruption meio- and 39% of macrofaunal species had returned. In addition, some new species not evident prior to the eruption were found. At the tubeworm site Tica, a total of 26

  3. Effect of venting and seating techniques on the cementation of complete coverage restorations.

    PubMed

    Cruz, Mark A; Sorenson, John A; Johnson, Warren K

    2008-01-01

    The incomplete seating of crowns resulting from cementation phenomena is a universal problem for clinicians. This seating error may lead to disturbances in the occlusion, proximal contacts, reduced retention and open margins. Various cementation protocols are practiced, with no established standard that maximizes crown seating and marginal fit. This study investigated the effect of various combinations of venting and cementation seating techniques with the routine use of die relief on the seating of complete gold crowns. Fifty human molars were prepared with a mounted handpiece for complete coverage crowns with a featheredge finish line and six degrees of taper, according to Tylman. Impressions were made, stone dies fabricated, die spacer was applied and the crowns were waxed and cast in type III gold. The respective crowns were placed on the teeth and preloaded. The distance between reference marks on the tooth and crown were measured at four points around each tooth. Zinc phosphate cement was mixed and the crowns were cemented in the following groups: (1) vented, tapping the crown into place with a mallet, (2) non-vented, tapping the crown into place, (3) vented static seating with a 25 kg load, (4) non-vented dynamic seating, (5) non-vented static loading with a 25 kg load. A 25 kg load was then maintained on the crowns during the cement setting time. Distances between reference marks were then measured and the change in post-cementation distances calculated. ANOVA (F = 14.995, p < .0001) and multiple range tests revealed significant differences between the groups. The mean increased post-cementation distances for the seating groups were (microm): 1) 132 +/- 20, 2) 372 +/- 26, 3) 367 +/- 59, 4) 239 +/- 35, 5) 537 +/- 45. The vented tapping technique produced the best seating. The non-vented tapping seating group produced seating not significantly different from the vented static method. The non-vented static group had the worst seating, with a gap four times

  4. Acceptability of fissure sealants from the child's perspective.

    PubMed

    Morgan, A G; Madahar, A K; Deery, C

    2014-07-11

    To seek children's opinions about the acceptability of resin fissure sealant placement. Service evaluation using a child-centred questionnaire issued to a prospective sample of consecutive hospital patients.Method Questionnaires were issued to children, aged 3 to 16 years, immediately after resin fissure sealant placement in the Paediatric Dentistry Department in Sheffield. Participants used a three-point faces scale for positive, neutral and negative responses, arranged as a Likert scale with minimal text, to rate their treatment experiences and satisfaction with the dental visit. Two hundred questionnaires were returned. Overall, 96% (n = 191) recorded a positive or neutral response for the ease at which they coped with the procedure, with most children positive about having fissure sealants placed again (66%; n = 132). Further analysis demonstrated that children who had fissure sealants on a previous occasion found them easier than those having them for the first time (p <0.05, chi-squared test). Almost half of all participants where ambivalent about the taste and feeling (46%; n = 92 and 55%; n = 110 respectively). The vast majority of children were satisfied with the explanations provided by their operator. Most participants found having resin fissure sealants placed an overall acceptable procedure, with patient acceptance improving with increased treatment experience.

  5. Open Fissure Folds record coseismic loading and postseismic stress relaxation

    NASA Astrophysics Data System (ADS)

    Nüchter, Jens-Alexander

    2015-03-01

    Open Fissure Folds hosted by high pressure/low temperature metamorphic rocks of south Evia (Greece) are introduced, their structural and microstructural record is analysed, and a mechanical model is proposed. Open Fissure Folds are preserved as at least two parallel folded quartz-feldspar veins separated by narrow buckled rock columns. The veins originated as tensile cracks that propagated in the middle crust driven by high differential stress. Features diagnostic for Open Fissure Folds indicate that the rock columns represented the layers of high viscosity, and not the veins as consistently reported in many previous studies on folded veins. This record is taken to indicate that buckling of the rock columns initiated after arrest of the fractures and terminated prior to complete vein sealing. Accordingly, mechanical decoupling by open fissures allowed for buckling of the rock columns in response to episodic creep of the host rocks according to stress relaxation, as expected for postseismic deformation in the earthquake cycle. I propose that the parental fractures propagated in response to quasi-instantaneous coseismic loading of the middle crust. Buckling was attributed to transient postseismic creep and stress relaxation. Complete sealing of the veins occurred when stresses were largely relaxed. Each Open Fissure Fold records the stress and strain history of a single earthquake.

  6. Shape analysis of human brain interhemispheric fissure bending in MRI.

    PubMed

    Zhao, Lu; Hietala, Jarmo; Tohka, Jussi

    2009-01-01

    This paper introduces a novel approach to analyze Yakovlevian torque by quantifying the bending of human brain interhemispheric fissure in three-dimensional magnetic resonance imaging. It extracts the longitudinal medial surface between the cerebral hemispheres, which are segmented with an accurate and completely automatic technique, as the shape representation of the interhemispheric fissure. The extracted medial surface is modeled with a polynomial surface through least-square fitting. Finally, curvature features, e.g., principal, Gaussian and mean curvatures, are computed at each point of the fitted medial surface to describe the local bending of the interhemispheric fissure. This method was applied to clinical images of healthy controls (12 males, 7 females) and never-medicated schizophrenic subjects (11 males, 7 females). The hypothesis of the normal interhemispheric fissure bending (rightward in the occipital region) was quantitatively demonstrated. Moreover, we found significant differences (p < 0.05) between the male schizophrenics and healthy controls with respect to the interhemispheric fissure bending in the frontal and occipital regions. These results show that our method is applicable for studying abnormal Yakovlevian torque related to mental diseases.

  7. Evidence for a chemoautotrophically based food web at inactive hydrothermal vents (Manus Basin)

    NASA Astrophysics Data System (ADS)

    Erickson, K. L.; Macko, S. A.; Van Dover, C. L.

    2009-09-01

    Hydrothermal vents are ephemeral systems. When venting shuts down, sulfide-dependent taxa die off, and non-vent taxa can colonize the hard substrata. In Manus Basin (Papua New Guinea), where hydrothermally active and inactive sites are interspersed, hydroids, cladorhizid sponges, barnacles, bamboo corals, and other invertebrate types may occupy inactive sites. Carbon and nitrogen isotopic compositions of animals occupying inactive sites are consistent with nutritional dependence on either chemoautotrophically or photosynthetically produced organic material, but sulfur isotopic compositions of these animals point to a chemoautotrophic source of sulfur from dissolved sulfide in vent fluids rather than sulfur derived from seawater sulfate through photosynthesis. Given that suspension-feeding and micro-carnivorous invertebrates are the biomass dominants at inactive sites, the primary source of chemoautotrophic nutrition is likely suspended particulates and organisms delivered from nearby active vents.

  8. Evidence for a Chemoautotrophically Based Food Web at Inactive Hydrothermal Vents (Manus Basin)

    NASA Astrophysics Data System (ADS)

    van Dover, C. L.; Erickson, K.; Macko, S.

    2008-12-01

    Hydrothermal vents are ephemeral systems. When venting shuts down, sulfide-dependent taxa die off, and non-vent taxa can colonize the hard substrata. In Manus Basin (Papua New Guinea), where active and inactive sulfide mounds are interspersed, hydroids, cladorhizid sponges, barnacles, and bamboo sponges, and other invertebrate types may occupy inactive sulfide mounds. Carbon and nitrogen isotopic compositions of animals occupying inactive sulfide mounds are consistent with nutritional dependence on either chemoautotrophically or photosynthetically produced organic material, but sulfur isotopic compositions of these animals point to a chemoautotrophic source of sulfur from dissolved sulfide in vent fluids rather than sulfur derived from seawater sulfate through photosynthesis. Given that suspension-feeding and micro- carnivorous invertebrates are the biomass dominants at inactive sulfide mounds, the primary source of chemoautotrophic nutrition is likely suspended particulates and organisms delivered from nearby active vents.

  9. Cost considerations in the treatment of anal fissures.

    PubMed

    Brisinda, Giuseppe; Bianco, Giuseppe; Silvestrini, Nicola; Maria, Giorgio

    2014-08-01

    Anal fissure is a split in the lining of the distal anal canal. Lateral internal sphincterotomy remains the gold standard for treatment of anal fissure. Although technique is simple and effective, a drawback of this surgical procedure is its potential to cause minor but some times permanent alteration in rectal continence. Conservative approaches (such as topical application of ointment or botulinum toxin injections) have been proposed in order to treat this condition without any risk of permanent injury of the internal anal sphincter. These treatments are effective in a large number of patients. Furthermore, with the ready availability of medical therapies to induce healing of anal fissure, the risk of a first-line surgical approach is difficult to justify. The conservative treatments have a lower cost than surgery. Moreover, evaluation of the actual costs of each therapeutic option is important especially in times of economic crisis and downsizing of health spending.

  10. Comparative study of vent and seep macrofaunal communities in the Guaymas Basin

    NASA Astrophysics Data System (ADS)

    Portail, M.; Olu, K.; Escobar-Briones, E.; Caprais, J. C.; Menot, L.; Waeles, M.; Cruaud, P.; Sarradin, P. M.; Godfroy, A.; Sarrazin, J.

    2015-09-01

    Understanding the ecological processes and connectivity of chemosynthetic deep-sea ecosystems requires comparative studies. In the Guaymas Basin (Gulf of California, Mexico), the presence of seeps and vents in the absence of a biogeographic barrier, and comparable sedimentary settings and depths offers a unique opportunity to assess the role of ecosystem-specific environmental conditions on macrofaunal communities. Six seep and four vent assemblages were studied, three of which were characterised by common major foundation taxa: vesicomyid bivalves, siboglinid tubeworms and microbial mats. Macrofaunal community structure at the family level showed that density, diversity and composition patterns were primarily shaped by seep- and vent-common abiotic factors including methane and hydrogen sulfide concentrations, whereas vent environmental specificities (higher temperature, higher metal concentrations and lower pH) were not significant. The type of substratum and the heterogeneity provided by foundation species were identified as additional structuring factors and their roles were found to vary according to fluid regimes. At the family level, seep and vent similarity reached at least 58 %. All vent families were found at seeps and each seep-specific family displayed low relative abundances (< 5 %). Moreover, 85 % of the identified species among dominant families were shared between seep and vent ecosystems. This study provides further support to the hypothesis of continuity among deep-sea seep and vent ecosystems.

  11. Sill induced hydrothermal vent structures: what do they look like in the field?

    NASA Astrophysics Data System (ADS)

    Jerram, Dougal; Svensen, Henrik; Millett, John; Angkasa, Syahreza; Planke, Sverre; Silkoset, Petter; Polozov, Alexander

    2017-04-01

    Hydrothermal vent structures are formed when sills intrude into sedimentary basins and cause gas generation and escape. Such structures are important as they represent the mechanism of venting of the gases to the surface and as such their contribution to the gas budgets of large igneous provinces. The metamorphic reactions and gases formed are highly dependent on the host rocks that are intruded, and the development of the vents required certain conditions to be met for their formation. Many of the vent structures have been identified in offshore seismic data, yet few examples are recorded or identified in the field. The exceptions include the Siberia and Karoo examples, where different types of onshore vents have been realised. New inspection of sites within the North Atlantic Igneous Province, provide addition examples of venting structures, and ones which relate to the degassing associated with PETM event. In the past many of these structures have been misinterpreted or described as 'vent agglomerates', which means that there occurrence in onshore data sets is significantly underestimated. Additionally, close inspection of outcropping lava sequences can reveal vent structures which cut the early volcanic sequences allowing a relative age relationship to be established, which help to provide additional constraints on sill emplacement.

  12. Marginal Microleakage of Conventional Fissure Sealants and Self-Adhering Flowable Composite as Fissure Sealant in Permanent Teeth

    PubMed Central

    Rahimian-Imam, Sara; Fayazi, Mohammad Reza

    2015-01-01

    Objectives: Application of sealants is a safe and effective way to prevent occlusal caries in the posterior teeth. A successful sealant therapy depends on good isolation. Decreased steps of adhesive application may enable proper isolation and use of self-adhering flowable composites for sealant therapy. This study sought to compare the marginal microleakage of fissure sealants and self-adhering flowable composites in permanent teeth. Materials and Methods: This in vitro, experimental study was conducted on 60 extracted human premolar teeth. The teeth were divided randomly into two groups of 30. In the first group, fissure sealant (Clinpro, 3M ESPE, USA) was placed on the teeth. In the second group, self-adhering flowable composite (Vertise Flow, Kerr, USA) was applied as the sealant. Then, both groups were immersed in 0.5% fuchsin dye solution for 24 hours. Sectioned samples were observed with a stereomicroscope for the extent of dye penetration. Data were analyzed using SPSS 21 and the Mann-Whitney test (P<0.05). Results: Microleakage in the fissure sealant group was significantly higher than that in the self-adhering flowable composite group (P<0.001). Conclusion: Microleakage was less using self-adhering flowable composite compared to conventional fissure sealant; therefore, self-adhering flowable composite can be used as a suitable fissure sealant in permanent teeth. PMID:26884777

  13. Sill induced hydrothermal venting: A summary of our current understanding

    NASA Astrophysics Data System (ADS)

    Jerram, Dougal; Svenesn, Henrik; Planke, Sverre; Millett, John; Reynolds, Pete

    2017-04-01

    Hydrothermal vent structures which are predominantly related with the emplacement of large (>1000 km3) intrusions into the sub-volcanic basins represent a specific style of piercement structure, where climate-forcing gases can be transferred into the atmosphere and hydrosphere. In this case, the types and volumes of gas produced by intrusions is heavily dependent on the host-rock sediment properties that they intrude through. The distribution of vent structures can be shown to be widespread in Large Igneous Provinces for example on both the Norwegian and the Greenland margins of the North Atlantic Igneous Province (NAIP). In this overview we assess the distribution, types and occurrence of hydrothermal vent structures associated with LIPs. There is particular focus on those within the NAIP using mapped examples from offshore seismic data as well as outcrop analogues, highlighting the variability of these structures and their deposits. As the availability of 3D data from offshore and onshore increases, the full nature of the volcanic stratigraphy from the subvolcanic intrusive complexes, through the main eruption cycles into the piercing vent structures, can be realised along the entirety of volcanic rifted margins and LIPs. This will help greatly in our understanding of the evolving palaeo-environments, and climate contributions during the evolution of these short lived massive volcanic events.

  14. Tectonic and magmatic controls on the location of post-subduction monogenetic volcanoes in Baja California, Mexico, revealed through spatial analysis of eruptive vents

    NASA Astrophysics Data System (ADS)

    Germa, Aurélie; Connor, Laura J.; Cañon-Tapia, Edgardo; Le Corvec, Nicolas

    2013-12-01

    Post-subduction (12.5 Ma to less than 1 Ma) monogenetic volcanism on the Baja California peninsula, Mexico, formed one of the densest intra-continental areas of eruptive vents on Earth. It includes about 900 vents within an area ˜700 km long (N-S) and 70 to 150 km wide (W-E). This study shows that post-subduction volcanic activity was distributed along this arc and that modes exist in the volcano distribution, indicating that productivity of the magma source region was not uniform along the length of the arc. Vent clustering, vent alignments, and cone elongations were measured within eight monogenetic volcanic fields located along the peninsula. Results indicate that on a regional scale, vent clustering varies from north to south with denser spatial clustering in the north on the order of 1.9 × 10-1 vents/km2 to less dense clustering in the south on the order of 7.8 × 10-2 vents/km2. San Quintin, San Carlos, Jaraguay, and Santa Clara are spatially distinct volcanic fields with higher eruptive vent densities suggesting the existence of individual melt columns that may have persisted over time. In contrast, the San Borja, Vizcaino, San Ignacio, and La Purisima vent fields show lower degrees of vent clustering and no obvious spatial gaps between fields, thus indicating an area of more distributed volcanism. Insight into the lithospheric stress field can be gained from vent alignments and vent elongation measurements. Within the fields located along the extinct, subduction-related volcanic arc, elongation patterns of cinder cones and fissure-fed spatter cones, vent clusters, and vent alignments trend NW-SE and N-S. Within the Santa Clara field, located more to the west within the forearc, elongation patterns of the same volcanic features trend NE-SW. These patterns suggest that magmatism was more focused in the forearc and in the northern part of Baja California than in its southern region. Within the extinct arc, magma ascent created volcano alignments and elongate

  15. Microleakage and penetration depth of different fissure sealant materials after cyclic thermo-mechanic and brushing simulation.

    PubMed

    Hatirli, Hüseyin; Yasa, Bilal; Yasa, Elif

    2017-08-25

    The aim of the study was to evaluate microleakage and the penetration-depths of different fissure-sealant materials applied with/without enameloplasty after cyclic aging. One-hundred-sixty mandibular molars were divided into non-invasive and enameloplasty preparation groups and eight material subgroups, including: flowable composites (microhyrid, nanohybrid, and nanofilled), three resin-based (unfilled, filled, and highly-filled), a giomer-based, and a glass-ionomer-based fissure sealant. Specimens were subjected to two-year cyclic chewing and brushing simulation. After 5% basic-fuchsin dye penetration, specimens were sectioned and scored under stereomicroscope. Kruskal-Wallis statistical data showed that preparation type significantly affected the penetration of all tested materials (p<0.05), but not significantly affected microleakage (p>0.05). Flowable composites showed the best and the glass-ionomer-based sealant showed the worst penetration and microleakage. Slight preparation of fissures is not important in microleakage. However, enameloplasty significantly enhanced the depth of penetration of the sealants. Flowable composites offer promising results at the fissure sealing.

  16. Explosive Volcanic Eruptions from Linear Vents on Earth, Venus and Mars: Comparisons with Circular Vent Eruptions

    NASA Technical Reports Server (NTRS)

    Glaze, Lori S.; Baloga, Stephen M.; Wimert, Jesse

    2010-01-01

    Conditions required to support buoyant convective plumes are investigated for explosive volcanic eruptions from circular and linear vents on Earth, Venus, and Mars. Vent geometry (linear versus circular) plays a significant role in the ability of an explosive eruption to sustain a buoyant plume. On Earth, linear and circular vent eruptions are both capable of driving buoyant plumes to equivalent maximum rise heights, however, linear vent plumes are more sensitive to vent size. For analogous mass eruption rates, linear vent plumes surpass circular vent plumes in entrainment efficiency approximately when L(sub o) > 3r(sub o) owing to the larger entrainment area relative to the control volume. Relative to circular vents, linear vents on Venus favor column collapse and the formation of pyroclastic flows because the range of conditions required to establish and sustain buoyancy is narrow. When buoyancy can be sustained, however, maximum plume heights exceed those from circular vents. For current atmospheric conditions on Mars, linear vent eruptions are capable of injecting volcanic material slightly higher than analogous circular vent eruptions. However, both geometries are more likely to produce pyroclastic fountains, as opposed to convective plumes, owing to the low density atmosphere. Due to the atmospheric density profile and water content on Earth, explosive eruptions enjoy favorable conditions for producing sustained buoyant columns, while pyroclastic flows would be relatively more prevalent on Venus and Mars. These results have implications for the injection and dispersal of particulates into the planetary atmosphere and the ability to interpret the geologic record of planetary volcanism.

  17. Geomorphologic evolution of the eruptive vent of September 2016 at Piton de la Fournaise (La Réunion)

    NASA Astrophysics Data System (ADS)

    Mergili, Martin; Villeneuve, Nicolas; Peltier, Aline

    2017-04-01

    The Piton de la Fournaise shield volcano on the island of La Réunion has been characterized by repeated activity since the first regular observations in the middle of the 17th century. It is shaped by a system of calderas of different ages, with the most recent one having formed in 2007 at the summit when the Cratère Dolomieu subsided by approx. 350 m within a short period of time. In the past years, activity has concentrated to several fissures and vents located along the outer slopes of the summit cone and within the surrounding caldera, Enclos Fouqué. The present contribution focuses on a geomorphologic description of the eruptive vent of the latest eruption that occurred between 11 and 18 September 2016 at Piton de la Fournaise. The course of the eruption will be illustrated through series of observations, photographs (compiled in time-lapse sequences) and geophysical data acquired by the instruments of the Volcanological Observatory (OVPF). Even though this eruption has been preceded by only a few long-term precursors, the dike propagation to the surface has been accompanied, as usual on this volcano, by a strong seismic crisis and ground deformation that lasted 56 minutes, from 03:45 to 04:41 Universal Time (UT). The beginning of the eruption has been marked by the appearance of the eruptive tremor on the seismic recordings at 04:41 UT. Ejection of lava fountains and the source of lava flows were observed on a length of approx. 1 km along the progressive opening of 7 en échelon fissures, from the northern slope of the summit cone down to the floor of the Enclos Fouqué caldera (elevation: 2340-2160 m asl). During the first hours, lava fountains were 15-30 m high. From the evening of 11 September, the fountain activity slowly confined to three (13 September) and then to two main vents (14 September) in the lower portion of the fissures. Those two vents finally coalesced on 15 September as an elongated cone where two eruptive outlets were still visible

  18. Mineralization of Alvinella polychaete tubes at hydrothermal vents

    PubMed Central

    Georgieva, M N; Little, C T S; Ball, A D; Glover, A G

    2015-01-01

    Alvinellid polychaete worms form multilayered organic tubes in the hottest and most rapidly growing areas of deep-sea hydrothermal vent chimneys. Over short periods of time, these tubes can become entirely mineralized within this environment. Documenting the nature of this process in terms of the stages of mineralization, as well as the mineral textures and end products that result, is essential for our understanding of the fossilization of polychaetes at hydrothermal vents. Here, we report in detail the full mineralization of Alvinella spp. tubes collected from the East Pacific Rise, determined through the use of a wide range of imaging and analytical techniques. We propose a new model for tube mineralization, whereby mineralization begins as templating of tube layer and sublayer surfaces and results in fully mineralized tubes comprised of multiple concentric, colloform, pyrite bands. Silica appeared to preserve organic tube layers in some samples. Fine-scale features such as protein fibres, extracellular polymeric substances and two types of filamentous microbial colonies were also found to be well preserved within a subset of the tubes. The fully mineralized Alvinella spp. tubes do not closely resemble known ancient hydrothermal vent tube fossils, corroborating molecular evidence suggesting that the alvinellids are a relatively recent polychaete lineage. We also compare pyrite and silica preservation of organic tissues within hydrothermal vents to soft tissue preservation in sediments and hot springs. PMID:25556400

  19. Mineralization of Alvinella polychaete tubes at hydrothermal vents.

    PubMed

    Georgieva, M N; Little, C T S; Ball, A D; Glover, A G

    2015-03-01

    Alvinellid polychaete worms form multilayered organic tubes in the hottest and most rapidly growing areas of deep-sea hydrothermal vent chimneys. Over short periods of time, these tubes can become entirely mineralized within this environment. Documenting the nature of this process in terms of the stages of mineralization, as well as the mineral textures and end products that result, is essential for our understanding of the fossilization of polychaetes at hydrothermal vents. Here, we report in detail the full mineralization of Alvinella spp. tubes collected from the East Pacific Rise, determined through the use of a wide range of imaging and analytical techniques. We propose a new model for tube mineralization, whereby mineralization begins as templating of tube layer and sublayer surfaces and results in fully mineralized tubes comprised of multiple concentric, colloform, pyrite bands. Silica appeared to preserve organic tube layers in some samples. Fine-scale features such as protein fibres, extracellular polymeric substances and two types of filamentous microbial colonies were also found to be well preserved within a subset of the tubes. The fully mineralized Alvinella spp. tubes do not closely resemble known ancient hydrothermal vent tube fossils, corroborating molecular evidence suggesting that the alvinellids are a relatively recent polychaete lineage. We also compare pyrite and silica preservation of organic tissues within hydrothermal vents to soft tissue preservation in sediments and hot springs.

  20. Selection for fissure resistance now made possible in early breeding generations

    USDA-ARS?s Scientific Manuscript database

    Rice kernel fissuring is one of the leading causes of milling yield losses. Any reduction in fissuring can result in direct increases in yield and profit for both producers and millers. While most U.S. rice varieties yield around 55% head rice, the fissure-resistant varieties ‘Cypress’, ‘Saber’ an...

  1. New method opens opportunity to proactively select for fissure resistance in early breeding generations

    USDA-ARS?s Scientific Manuscript database

    WANTED: New rice varieties improved for resistance to kernel fissuring. Rice kernel fissuring is one of the leading causes of reduced milling yield. Any reduction in fissuring can result in direct increases in yield and profit for both producers and millers. While most U.S. rice varieties yield a...

  2. Investigation of the subsurface geometry of fissure-ridge travertine with GPR, Pamukkale, western Turkey

    NASA Astrophysics Data System (ADS)

    Çaǧlar Yalçiner, Cahit

    2013-06-01

    Cracks in the upper crust are the result of either local or regional tectonic stress. Such structural elements are conduits for fluids in the crust. In Pamukkale, hot water which is rich in calcium carbonate emerges from fissures. The hot water issuing from the fissures precipitates travertine both in the fissures and on the surface. As a result, a ridge, which is called fissure-ridge travertine, forms along the central fissure. Fissure-ridge travertines are lens-shaped at the surface. Since fissure-ridge travertines are of great tectonic significance, their surface characteristics have been studied in detail. However, the subsurface geometry of travertine ridges is not well known. GPR was used to examine the subsurface geometry of fissure-ridge travertine and the central fissure. GPR profiles were combined across the ridge to produce a three-dimensional (3D) subsurface image of the travertine mass. The 3D image showed that the thickness and width of the travertine mass are at a maximum near the centre of the ridge and they both decrease asymmetrically towards the ends. Perpendicular GPR slices across the central fissure showed that the thickness of the vertically banded fissure-travertine increases with depth. 3D modelling suggests that the lateral propagation of the central fissure is asymmetric.

  3. Dental Pit and Fissure Sealants: Implications for School Health Personnel.

    ERIC Educational Resources Information Center

    McCormack-Brown, K. R.; And Others

    1989-01-01

    To promote good personal hygiene practices in students, school health personnel must be informed about dental pit and fissure sealants and related programs. Adoption and maintenance of such programs may depend on the success of school health personnel in educating administrators and policymakers. (SM)

  4. Flow characteristics and sealing ability of fissure sealants.

    PubMed

    Barnes, D M; Kihn, P; von Fraunhofer, J A; Elsabach, A

    2000-01-01

    This study evaluated the relationship between fissure sealant viscosity, leakage prevention and the incidence of void formation of five commercially available pit-and-fissure sealants. Seventy-two intact, caries free human pre-molars and molars were divided into six test groups of 12 teeth each. All teeth were cleaned with a flour of pumice prophylaxis followed by etching for 60 seconds with 37% H3PO4, rinsing for 30 seconds and drying with oil-free air. Five commercial, light-cured fissure sealants and an unfilled version of one sealant were applied following manufacturers' instructions. Teeth were thermal cycled for 5000 cycles from 5-50 degrees C with a one-minute dwell time at each temperature. Silver nitrate staining followed by mesiodistal sectioning was performed. Leakage and void formation were evaluated at X50 optical magnification. Viscosity was assessed by syringing the fissure sealants into short pipettes, allowing free flow for 30 seconds and then light curing for one minute. The length of unfilled capillary was measured with a Vernier gauge. All experimental data was subjected to a one-way ANOVA, and where differences were detected, they were identified by a post hoc Tukey hsd test at a priori alpha = 0.05. Based on the conditions of the study, viscosity and flow characteristics had no effect on sealing ability or void formation.

  5. Dental Pit and Fissure Sealants: Implications for School Health Personnel.

    ERIC Educational Resources Information Center

    McCormack-Brown, K. R.; And Others

    1989-01-01

    To promote good personal hygiene practices in students, school health personnel must be informed about dental pit and fissure sealants and related programs. Adoption and maintenance of such programs may depend on the success of school health personnel in educating administrators and policymakers. (SM)

  6. Hemorrhoids and anal fissures in inflammatory bowel disease.

    PubMed

    D'Ugo, S; Stasi, E; Gaspari, A L; Sileri, P

    2015-12-01

    Perianal disease is a common complication of inflammatory bowel disease (IBD). It includes different conditions from more severe and potentially disabling ones, such as abscesses and fistulas, to more benign conditions such as hemorrhoids, skin tags and fissures. Most literature has been focused on anal sepsis and fistulae, as they carry the majority of disease burden and often alter the natural course of the disease. Hemorrhoids and anal fissures in patients with IBD have been overlooked, although they can represent a challenging problem. The management of hemorrhoids and fissures in IBD patients may be difficult and may significantly differ compared to the non-affected population. Historically surgery was firmly obstructed, and hemorrhoidectomy or sphincterotomy in patients with associated diagnosis of IBD was considered harmful, although literature data is scant and based on small series. Various authors reported an incidence of postoperative complications higher in IBD than in the general populations, with potential severe events. Considering that a spontaneous healing is possible, the first line management should be a medical therapy. In patients non-responding to conservative measures it is possible a judicious choice of surgical options on a highly selective basis; this can lead to acceptable results, but the risk of possible complications needs to be considered. In this review it is analyzed the current literature on the incidence, symptoms and treatment options of hemorrhoids and anal fissures in patients with Crohn's disease and ulcerative colitis.

  7. Botulinum toxin A in anal fissures: a modified technique.

    PubMed

    Wollina, U; Konrad, H

    2002-09-01

    Anal fissures are common and painful. Botulinum toxin A (BTXA) is considered to be the most potent non-surgical treatment; however, no attention has been paid to associated hyperhidrosis. To compare traditional BTXA treatment of muscular spasticity in anal fissures with combined treatment of spasticity and focal hyperhidrosis of the anal fold and perianal skin. Outpatient department of a dermatological hospital. Ten patients with chronic anal fissures (of more than 6 months duration who failed to respond to conservative treatment and who had refused surgery) associated with focal hyperhidrosis as assessed by Minor's sweat test were investigated in an open, two-armed trial. Intramuscular injections of 20-25 U BTXA (Botox) were performed in group A (n = 5). In group B (n = 5) those injections were combined with intracutaneous injection of 30-50 U BTXA to treat focal hyperhidrosis. Mean follow-up was 5 months. Five of five patients in group B but only two of five patients in group A experienced a complete remission despite the fact that relief of pain was evident in eight of 10 patients within 2 weeks. Patient satisfaction with treatment was high but slightly better in group B. This open trial suggests that combined therapy of both muscular spasticity and focal hyperhidrosis may provide better results than intramuscular injections alone in anal fissure therapy with BTXA.

  8. Internal sphincterotomy versus topical nitroglycerin ointment for chronic anal fissure.

    PubMed

    Aslam, Muhammad I; Pervaiz, Arif; Figueiredo, Rodrigo

    2014-01-01

    Anal fissure is a common benign condition. An anorectal problem is defined as a split in the anal canal mucosa that extends from the dentate line to the anal verge. Chronic anal fissure is defined by a history of symptoms present for more than 2 months' duration and with a triad of external skin tags, namely, a hypertrophied anal papilla, an ulcer with rolled edges, and a base exposing the internal sphincter. Because complications such as incontinence are associated with surgical treatment, chemical sphincterotomy is currently favored. The objective of this study is to compare the difference in outcome between open partial lateral anal sphincterotomy and application of topical 0.2% nitroglycerin ointment for the treatment of chronic anal fissure. This was a quasi-experimental study carried out between January 16, 2007 and January 15, 2008 in the Surgical Department of Jinnah Hospital, Lahore, Pakistan. Sixty consecutive cases with a clinical diagnosis of chronic anal fissure were recruited in the study. All recruited patients met the study inclusion criteria and were randomly assigned to one of the two groups. Group A was managed conservatively using topical 0.2% nitroglycerin ointment, whereas Group B underwent open partial lateral anal sphincterotomy. Both groups were followed up at 1 week, 2 weeks, 4 weeks, and 6 weeks after the treatment. All the patients complained of pain. A total of 43 (71.7%) patients had pain with constipation, whereas 31 (51.7%) patients had bleeding per rectum. Upon clinically examining the anal area, tenderness was elicited in all 60 (100%) patients. Group A included 30 (11 females and 19 males) cases treated with topical 0.2% nitroglycerin ointment and Group B included 30 (11 females and 19 males) cases who underwent open partial lateral anal sphincterotomy. In Group A, only 15 patients with fissures were successfully treated (50%). By contrast, 28 (93%) patients with fissures in Group B were successfully treated, and only two (7

  9. Draft Genome Sequence for the Type Strain Vulcanibacillus modesticaldus BR, a Strictly Anaerobic, Moderately Thermophilic, and Nitrate-Reducing Bacterium Isolated from Deep-Sea Hydrothermal Vents of the Mid-Atlantic Ridge.

    PubMed

    Abin, Christopher A; Hollibaugh, James T

    2016-11-10

    Vulcanibacillus modesticaldus BR(T) was isolated from calcite-rich, metalliferous core samples collected at the Rainbow deep-sea hydrothermal vent field on the Mid-Atlantic Ridge. Here, we report the 2.2-Mb draft genome sequence for this strain, consisting of 100 contigs with a G+C content of 33.6% and 2,227 protein-coding sequences. Copyright © 2016 Abin and Hollibaugh.

  10. Draft Genome Sequence for the Type Strain Vulcanibacillus modesticaldus BR, a Strictly Anaerobic, Moderately Thermophilic, and Nitrate-Reducing Bacterium Isolated from Deep-Sea Hydrothermal Vents of the Mid-Atlantic Ridge

    PubMed Central

    Abin, Christopher A.

    2016-01-01

    Vulcanibacillus modesticaldus BRT was isolated from calcite-rich, metalliferous core samples collected at the Rainbow deep-sea hydrothermal vent field on the Mid-Atlantic Ridge. Here, we report the 2.2-Mb draft genome sequence for this strain, consisting of 100 contigs with a G+C content of 33.6% and 2,227 protein-coding sequences. PMID:27834704

  11. Monitoring of the volcanic rock compositions during the 2012-2013 fissure eruption at Tolbachik volcano, Kamchatka

    NASA Astrophysics Data System (ADS)

    Volynets, Anna O.; Edwards, Benjamin R.; Melnikov, Dmitry; Yakushev, Anton; Griboedova, Irina

    2015-12-01

    Here we present the results from monitoring of the composition of rocks produced during the 2012-2013 fissure eruption at Tolbachik volcano (FTE). Major and trace element concentrations in 75 samples are reported. Products of this eruption are represented by high alumina basaltic trachyandesites with higher alkalis and titanium contents than in all previously studied rocks of the Tolbachik monogenetic volcanic field. Rocks erupted during the first three days (27-30 November) from the northern (also called Menyailov) group of vents are the most silica- and alkali-rich (SiO2 concentrations up to 55.35 wt.% and K2O up to 2.67 wt.%). From December onwards, when the eruptive activity switched from the Menyailov vents to the southern (Naboko) group of vents, silica content dropped by 2 wt.%, concentrations of MgO, FeO, TiO2 and Mg# increased, and K2O and Na2O concentrations and K2O/MgO ratio decreased. For the rest of the eruption the compositions of rocks remained constant and homogeneous; no systematic compositional differences between lava, bombs and scoria samples are evident. Trace element distributions in the rocks of the Menyailov and Naboko vent lavas are relatively uniform; Menyailov lavas have slightly higher Th, Nb, Hf, Y, and HREE concentrations than the Naboko vent lavas at more or less constant element ratios. We explain the initial change in geochemistry by tapping of a slightly cooler and fractionated (~ 3% Mt and 8% Cpx) upper part of the magma storage zone before the main storage area began to feed the eruption. Thermodynamic constraints show that apparent liquidus temperatures varied from 1142 °C to 1151 °C, and thermodynamic modeling shows that variations in compositions are consistent with a high degree of low pressure (100-300 MPa), nominally anhydrous fractionation of a parent melt compositionally similar to the 1975 Northern Breakthrough high-Mg basalt. Geochemistry, petrological observations and modeling are in agreement with the newly erupted

  12. 24 CFR 3280.710 - Venting, ventilation and combustion air.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...: (1) An integral vent system listed or certified as part of the appliance. (2) A venting system... roof line or outside the wall line may be installed at the site. Sectional venting systems shall...

  13. Use of plumbing vents for venting flue products. Topical report, September 1985-January 1986

    SciTech Connect

    Schneider, S.; Thrasher, W.H.

    1986-01-01

    The report contains the results of a literature review of plumbing codes and a technical feasibility assessment of using plumbing vents for venting flue products. The literature survey identifies the code-related issues of connecting gas-fired appliances to plumbing vents. These issues and other adverse conditions possibly created by the connection of gas-fired appliances are investigated in the feasibility assessment. The conclusion is that venting of gas-fired appliances into plumbing vents is technically feasible, if certain conditions are met and if a suitable means of preventing sewer gas from entering the living space is available.

  14. Remineralization Capacity of Three Fissure Sealants with and without Gaseous Ozone on Non-Cavitated Incipient Pit and Fissure Caries.

    PubMed

    Unal, M; Oztas, N

    2015-01-01

    The purpose of this study was to investigate the remineralization activation of the application of three fissure sealants (FSs), alone or with gaseous ozone (GO), on non-cavitated initial caries and evaluate the clinical success of FS. Sixty children who had DIAGNOdent scores between 10-30 on bilateral symmetric mandibular first permanent molars were included in study. In a split-mouth design, teeth were assigned to experimental (with GO) and control (without GO) groups. GO was applied to teeth on one side and then the same brand of randomly selected FSs was applied to the teeth on both sides. Children were divided into 3 groups based on type of FS (Group 1: Aegis {Bosworth Co, North Hamlin Avenue Skokie, Illinois, USA}, Group 2: Fuji Triage {GC, Tokyo, Japan}, Group 3: Helioseal {Ivoclar Vivadent, Liechtenstein, Germany}). All FSs were then examined for retention rates at 1, 3, 6, 9, and 12 months; at the end of 12 months, all FSs were removed with an air-abrasion device and DIAGNOdent scores noted to compare with the initial values. The application of GO with either Fuji Triage or Aegis FS was effective on remineralization (p<0.05); however, the application of Helioseal FSs was not effective (p>0.05). The 1(st) and 12(th) months' full retention rates of Fuji Triage FSs was a significant difference (p<0.05) from other FSs (Aegis and Helioseal) (p>0.05). GO+Aegis FS showed the highest remineralization; and, at the end of 12 months, its clinical success was higher than other FSs.

  15. 46 CFR 151.15-5 - Venting.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...) Pressure-vacuum venting. A normally closed venting system fitted with a device to automatically limit the pressure or vacuum in the tank to design limits. Pressure-vacuum relief valves shall comply with the... devices in accordance with the requirements of § 54.15-13 of this chapter. (2) When a...

  16. Anal fissures in infants may be a pathognomonic sign of infants with cow's milk allergy.

    PubMed

    Jirapinyo, Pipop; Densupsoontorn, Narumon; Kangwanpornsiri, Channagarn

    2013-07-01

    To study the association between analfissures and cow's milk allergy (CMA) in infants. METHODS AND METHOD: In a prospective study, 72 confirmed cases of CMA in infants were examined for anal fissure by pediatricians with five years' experience. A positive finding was defined as when an anal fissure was detected by at least two out of three examiners. Of infants with CMA with and without gastrointestinal GI symptoms, 79% and 83% had anal fissures, respectively The prevalence of anal fissure in these infants is significantly higher than in normal infants. Anal fissure may be a pathognomonic sign of cow's milk allergy in infants.

  17. Evidence-based Clinical Practice Guideline for the Use of Pit-and-Fissure Sealants.

    PubMed

    2016-10-15

    This article presents evidence-based clinical recommendations for the use of pit-and-fissure sealants on the occlusal surfaces of primary and permanent molars in children and adolescents. A guideline panel convened by the American Dental Association (ADA) Council on Scientific Affairs and the American Academy of Pediatric Dentistry conducted a systematic review and formulated recommendations to address clinical questions in relation to the efficacy, retention, and potential side effects of sealants to prevent dental caries; their efficacy compared with fluoride varnishes; and a head-to-head comparison of the different types of sealant material used to prevent caries on pits-and-fissures of occlusal surfaces. This is an update of the ADA 2008 recommendations on the use of pit-and-fissure sealants on the occlusal surfaces of primary and permanent molars. The authors conducted a systematic search in MEDLINE, Embase, Cochrane Central Register of Controlled Trials, and other sources to identify randomized controlled trials reporting on the effect of sealants (available on the U.S. market) when applied to the occlusal surfaces of primary and permanent molars. The authors used the Grading of Recommendations Assessment, Development, and Evaluation approach to assess the quality of the evidence and to move from the evidence to the decisions. The guideline panel formulated 3 main recommendations. They concluded that sealants are effective in preventing and arresting pit-and-fissure occlusal carious lesions of primary and permanent molars in children and adolescents compared with the nonuse of sealants or use of fluoride varnishes. They also concluded that sealants could minimize the progression of non-cavitated occlusal carious lesions (also referred to as initial lesions) that receive a sealant. Finally, based on the available limited evidence, the panel was unable to provide specific recommendations on the relative merits of 1 type of sealant material over the others

  18. Evidence-based Clinical Practice Guideline for the Use of Pit-and-Fissure Sealants.

    PubMed

    2016-10-01

    This article presents evidence-based clinical recommendations for the use of pit-and-fissure sealants on the occlusal surfaces of primary and permanent molars in children and adolescents. A guideline panel convened by the American Dental Association (ADA) Council on Scientific Affairs and the American Academy of Pediatric Dentistry conducted a systematic review and formulated recommendations to address clinical questions in relation to the efficacy, retention, and potential side effects of sealants to prevent dental caries; their efficacy compared with fluoride varnishes; and a head-to-head comparison of the different types of sealant material used to prevent caries on pits-and-fissures of occlusal surfaces. This is an update of the ADA 2008 recommendations on the use of pit-and-fissure sealants on the occlusal surfaces of primary and permanent molars. The authors conducted a systematic search in MEDLINE, Embase, Cochrane Central Register of Controlled Trials, and other sources to identify randomized controlled trials reporting on the effect of sealants (available on the U.S. market) when applied to the occlusal surfaces of primary and permanent molars. The authors used the Grading of Recommendations Assessment, Development, and Evaluation approach to assess the quality of the evidence and to move from the evidence to the decisions. The guideline panel formulated 3 main recommendations. They concluded that sealants are effective in preventing and arresting pit-and-fissure occlusal carious lesions of primary and permanent molars in children and adolescents compared with the nonuse of sealants or use of fluoride varnishes. They also concluded that sealants could minimize the progression of non-cavitated occlusal carious lesions (also referred to as initial lesions) that receive a sealant. Finally, based on the available limited evidence, the panel was unable to provide specific recommendations on the relative merits of 1 type of sealant material over the others

  19. Hydrothermal Vents in Yellowstone Lake: Chemical Fluxes, Siliceous Deposits, and Collapse Structures

    NASA Astrophysics Data System (ADS)

    Shanks, W. P.; Morgan, L. A.; Balistrieri, L.; Alt, J.; Meeker, G.

    2002-12-01

    The geochemistry of Yellowstone Lake is strongly influenced by sublacustrine hydrothermal vent activity. The hydrothermal source fluid is identified using Cl and dD data on water column and sublacustrine hydrothermal vent fluid samples. Silica-rich hydrothermal deposits occur on the lake bottom near active and presently inactive hydrothermal vents. Pipe- and flange-like deposits contain cemented and recrystallized diatoms and represent pathways for hydrothermal fluid migration. Another major type of hydrothermal deposit comprises hard, porous siliceous spires up to 7 m tall that occur in 15 m of water in Bridge Bay. Bridge Bay spires are hydrothermal silica deposits formed in place by growth of chimney-like features from lake-bottom hydrothermal vents. The Cl concentrations indicate that Yellowstone Lake water is about 1 percent hydrothermal source fluid and 99 percent inflowing stream water and that the flux is about 10 percent of the total hydrothermal water flux in Yellowstone National Park. With recent swath-sonar mapping studies that show numerous new hydrothermal features, Yellowstone Lake should now be considered one of the most significant hydrothermal basins in the Park. Many lake-bottom hydrothermal vents occur in small depressions that are clearly imaged on multibeam sonar, some of which are interpreted as collapse structures based on seismic reflection data. Sediments collected from such vents show chemical evidence of leaching of 60-70 wt. percent SiO2, which may result in volume reductions up to 80 percent and provides a mechanism for vent structure formation.

  20. Shaped Charge Jet/Propellant Interactions in a Vented Compartment.

    DTIC Science & Technology

    1979-12-01

    the vented ammunition compartment. One of these was the Susquehanna Instruments Model ST-4 tourmaline transducer, a nonresonant transducer capable of...S1-4 tourmaline gauges and those at positons 3 and 4 were Kistler Model 617A tourmaline gauges. Thin strips of metal were welded over the trans- ducers...two different types of piezoelectric transducers. One was a fast almost totally non- resonant though somewhat temperature sensitive Tourmaline bar gauge

  1. Imaging findings of pulmonary granulomatosis with polyangiitis (Wegener's granulomatosis): lesions invading the pulmonary fissure, pleura or diaphragm mimicking malignancy.

    PubMed

    Guneyli, Serkan; Ceylan, Naim; Bayraktaroglu, Selen; Gucenmez, Sercan; Aksu, Kenan; Kocacelebi, Kenan; Acar, Turker; Savas, Recep; Alper, Hudaver

    2016-11-01

    Granulomatosis with polyangiitis (GPA, formerly Wegener's granulomatosis), in which pulmonary involvement often predominates, is a multisystem granulomatous, necrotizing vasculitis that affects small and medium-sized vessels. In this study we evaluated various radiological findings of pulmonary GPA and focused on spiculated pulmonary lesions invading the pulmonary fissure, pleura or diaphragm mimicking malignancy. This retrospective study included 48 patients, aged 28-73 (mean, 47.3) years, who showed either histopathological diagnosis of GPA (n = 39) or elevated levels of the cytoplasmic anti-neutrophilic cytoplasmic antibody serum marker (n = 9) between January 2003 and December 2013. All patients received a chest computed tomography (CT), and the types of pulmonary lesions were defined and evaluated. Among the 48 patients, 33 had abnormal pulmonary findings on CT. The most commonly detected pulmonary lesion types were nodules and masses (n = 126) observed in 24 patients. Cavitation, necrosis, spiculation and invasion of the fissure, pleura or diaphragm were observed in 14, 9, 10 and 6 patients, respectively. Consolidation was found in 14 patients and thickening of bronchial wall in 8 patients. Pulmonary lesion types of GPA have a wide spectrum, potentially mimicking a high number of diseases including malignancy, infection and noninfectious inflammatory diseases. A spiculated lung lesion invading the fissure, pleura or diaphragm is mostly present in malignancy, but it can be also seen in GPA.

  2. The effect of vegetation on infiltration in shallow soils underlain by fissured bedrock

    NASA Astrophysics Data System (ADS)

    Stothoff, S. A.; Or, D.; Groeneveld, D. P.; Jones, S. B.

    1999-05-01

    Mean annual infiltration above the high-level waste repository proposed to be sited at Yucca Mountain, Nevada, has a large impact on assessments of repository performance. Ongoing investigations of infiltration processes have identified the relatively horizontal caprock environment above portions of the repository as a potentially large source of infiltrating waters, due to shallow, permeable soils above a moderately welded tuff with large soil-filled fissures. The combination of shallow soils and fissured bedrock allows rapid penetration of wetting pulses to below the rooting zone. Plant uptake can strongly reduce net infiltration in arid environments with high water storage capacity, and, despite the low water storage capacity, there is a relatively high vegetation density in this environment. The apparent discrepancy between high vegetation density and low water storage motivates the study of plant-hydrologic interactions in this semiarid environment. Field observations were coupled with plant- and landscape-scale models to provide insight into plant-hydrologic interactions. Several lines of evidence, including: (i) linear plant growth features observed on aerial photographs; (ii) comparisons of plant cover within the fissured environment and comparable environments lacking fissures; and (iii) direct excavations, all suggest that the widely spaced soil-filled fissures are conducive to plant growth even when fissures are buried at soil depths exceeding 30 cm. Results from a mechanistic simulation model for root growth into fissures suggest that the additional (sheltered) plant-available soil water within fissures provides a competitive advantage for plant establishment. Therefore, plants that germinate above a fissure are more likely to survive, in turn developing linear features above fissures. Having established that plants preferentially root within soil-filled fissures in the caprock environment, a set of simulations were performed to examine the hydrologic

  3. Endemicity of the cosmopolitan mesophilic chemolithoautotroph Sulfurimonas at deep-sea hydrothermal vents.

    PubMed

    Mino, Sayaka; Nakagawa, Satoshi; Makita, Hiroko; Toki, Tomohiro; Miyazaki, Junichi; Sievert, Stefan M; Polz, Martin F; Inagaki, Fumio; Godfroy, Anne; Kato, Shingo; Watanabe, Hiromi; Nunoura, Takuro; Nakamura, Koichi; Imachi, Hiroyuki; Watsuji, Tomo-O; Kojima, Shigeaki; Takai, Ken; Sawabe, Tomoo

    2017-04-01

    Rich animal and microbial communities have been found at deep-sea hydrothermal vents. Although the biogeography of vent macrofauna is well understood, the corresponding knowledge about vent microbial biogeography is lacking. Here, we apply the multilocus sequence analysis (MLSA) to assess the genetic variation of 109 Sulfurimonas strains with ⩾98% 16S rRNA gene sequence similarity, which were isolated from four different geographical regions (Okinawa Trough (OT), Mariana Volcanic Arc and Trough (MVAT), Central Indian Ridge (CIR) and Mid-Atlantic Ridge (MAR)). Sequence typing based on 11 protein-coding genes revealed high genetic variation, including some allele types that are widespread within regions, resulting in 102 nucleotide sequence types (STs). This genetic variation was predominantly due to mutation rather than recombination. Phylogenetic analysis of the 11 concatenated genes showed a clear geographical isolation corresponding to the hydrothermal regions they originated from, suggesting limited dispersal. Genetic differentiation among Sulfurimonas populations was primarily influenced by geographical distance rather than gas composition of vent fluid or habitat, although in situ environmental conditions of each microhabitat could not be examined. Nevertheless, Sulfurimonas may possess a higher dispersal capability compared with deep-sea hydrothermal vent thermophiles. This is the first report on MLSA of deep-sea hydrothermal vent Epsilonproteobacteria, which is indicative of allopatric speciation.

  4. Inhomogeneites dans le Vent des Etoiles Wolf-Rayet

    NASA Astrophysics Data System (ADS)

    Robert, Carmelle

    1992-01-01

    Des mesures spectroscopiques effectuees avec un haut rapport signal sur bruit et une bonne resolution ont demontre l'existence de regions perturbees en mouvement dans le vent d'etoiles Wolf-Rayet (WR). L'echantillon d'objets etudies ici comprend 9 etoiles WR couvrant differents sous-types WN et WC. De nombreuses petites structures variables superposees au profil des raies d'emission formees dans le vent stellaire signalent la presence des perturbations. L'etude des variations globales des raies et l'examen des micro-structures individuelles ont permis de decrire plusieurs caracteristiques des perturbations. Entre autres, on observe des correlations significatives entre le niveau de variabilite des raies et certains parametres des etoiles qui confirment que le phenomene de variabilite est intrinseque au vent stellaire. En comparant les changements des vitesses radiales et des largeurs equivalentes des differentes raies d'une meme etoile, on conclut que les regions perturbees ont une etendue finie par rapport a l'enveloppe des etoiles. On peut facilement suivre les structures individuelles sur une periode de temps couvrant ~eq8 heures (et peut etre meme 24 heures) avant qu'elles ne disparaissent. Durant ce temps les structures se deplacent en s'eloignant du centre de la raie. A partir des differents comportements notes lors de l'analyse des variations globales et lors de l'examen des structures individuelles, on propose de representer les perturbations par un modele d'inhomogeneites discretes en expansion dans le vent. On suppose simplement que les inhomogeneites emettent comme le vent global (et absorbent aussi si le vent global montre un profil P Cyg). La superposition du graphique de l'acceleration radiale moyenne des inhomogeneites de WR140 en fonction de leur vitesse radiale et du modele theorique d'inhomogeneites qui suivent la loi generale de vitesse donne un taux d'acceleration lent, avec beta >= 3 pour les inhomogeneites de cette etoile. On obtient, entre

  5. Fissure sealants: Knowledge and practice of Yemeni dental practitioners.

    PubMed

    Al-Maweri, Sadeq Ali; Al-Jamaei, Aisha Ahmed; Halboub, Esam Saleh; Al-Soneidar, Walid Ahmed; Tarakji, Bassel; Alsalhani, Anas

    2016-01-01

    This study was conducted to evaluate Yemeni dental practitioners' knowledge and practices concerning fissure sealants. A modified questionnaire consisted of 25-items was distributed to 500 dentists working in Sana'a City. Descriptive statistics and Chi-square/Fisher's exact tests were used for statistical analyses. The response rate was 74%. Most of the respondents were male (61.3%), general practitioners (84.2%), and had <5 years of clinical experience (48.3%). The respondents showed a reasonable level of knowledge about sealants, with the majority (88%) believed that there is strong scientific evidence about fissure sealants effectiveness and around 90% showed a good understanding of sealant placement instructions. On the other hand, respondents showed insufficient knowledge about sealants clinical practice. Although a high proportion of dental practitioners showed adequate knowledge about dental sealant, following guidelines and standardized procedures in clinical practice is lacking. These emphasize the need for regular continuing education courses for dental professional.

  6. Innovations in chronic anal fissure treatment: A systematic review

    PubMed Central

    Poh, Aaron; Tan, Kok-Yang; Seow-Choen, Francis

    2010-01-01

    A chronic anal fissure is a common perianal condition. This review aims to evaluate both existing and new therapies in the treatment of chronic fissures. Pharmacological therapies such as glyceryl trinitrate (GTN), Diltiazem ointment and Botulinum toxin provide a relatively non-invasive option, but with higher recurrence rates. Lateral sphincterotomy remains the gold standard for treatment. Anal dilatation has no role in treatment. New therapies include perineal support devices, Gonyautoxin injection, fissurectomy, fissurotomy, sphincterolysis, and flap procedures. Further research is required comparing these new therapies with existing established therapies. This paper recommends initial pharmacological therapy with GTN or Diltiazem ointment with Botulinum toxin as a possible second line pharmacological therapy. Perineal support may offer a new dimension in improving healing rates. Lateral sphincterotomy should be offered if pharmacological therapy fails. New therapies are not suitable as first line treatments, though they can be considered if conventional treatment fails. PMID:21160880

  7. Morbidity associated with treatment of chronic anal fissure

    PubMed Central

    Latif, Ansar; Ansar, Anila; Butt, Muhammad Qasim

    2013-01-01

    Objective: To assess the effectiveness of different modes of treatment of chronic anal fissure as regards improvement of symptoms and complications. Methods: This prospective study included 129 consecutive patients with chronic anal fissures presented to the Surgical Outpatients’ Department of Islam Teaching Hospital Sialkot, Pakistan; from September 2010 to November 2012. Patients were distributed in three groups. In “OBG group”, patients had attended Gynae/Obs OPD and got treated and were then referred to surgical OPD for failure of treatment or recurrence. Patients who presented with history of treatment by GPs were included in “GP Group” “SGR Group” included those who directly reported to surgical OPD for treatment. Patients were managed both pharmacologically as OPD patients and surgically as admitted patients. Patients were instructed to apply small amounts of 0.2% GTN paste in soft white paraffin, to the anoderm with finger tips three times a day. Patients were evaluated at two-week intervals and at each visit the symptoms control, adverse effects and fissure status were recorded. If there was symptomatic relief or the fissure healing was in progress, the treatment was continued for a total duration of eight weeks. Operated patients were nursed in wards after surgery i.e Internal Anal Sphicterotomy. They were advised to report to OPD weekly for one month or earlier if they experienced any symptoms suggestive of complications. Patients were declared cured in case of complete symptomatic relief with fissure healing. Success, failure and associated problems were recorded and analysed to get results. Results:This study included 129 patients who could be followed up for a minimum of three months. These patients were referred by gynaecologist i.e. 22 (17%) for treatment failure while 5 patients with wrong diagnosis were not included in statistical analysis; similarly 41 (32%) patients were referred by general practitioners and 9 patients with wrong

  8. Venting of Pressure through Perforated Plates

    DTIC Science & Technology

    1978-09-01

    2623, May 1976. (AD #BO11616L) 4. W.A. Keenan and J.A. Tamareto, "Blaat Envirowaent from Fully and Partially Vented Exploaions in Cubicles". Civil...the scatter of experimental results obtained from vented structures and high explosives. In Reference 4, Keenan and Tamareto developed an equation to...May 1976. (AD #BO11616L) 4. W.A. Keenan and J.A. Tamareto, "Blast Environment from l’ullyand Partially Vented Explosions in Cubicles". Civil

  9. Monitoring arrangement for vented nuclear fuel elements

    DOEpatents

    Campana, Robert J.

    1981-01-01

    In a nuclear fuel reactor core, fuel elements are arranged in a closely packed hexagonal configuration, each fuel element having diametrically opposed vents permitting 180.degree. rotation of the fuel elements to counteract bowing. A grid plate engages the fuel elements and forms passages for communicating sets of three, four or six individual vents with respective monitor lines in order to communicate vented radioactive gases from the fuel elements to suitable monitor means in a manner readily permitting detection of leakage in individual fuel elements.

  10. Fluoride release and uptake abilities of different fissure sealants.

    PubMed

    Poggio, Claudio; Andenna, Gianluigi; Ceci, Matteo; Beltrami, Riccardo; Colombo, Marco; Cucca, Lucia

    2016-07-01

    The long-term capability of resin sealants and glass ionomer cements to release fluoride is associated to a reduction in pit and fissure caries. The regular use of fluoride varnishes/toothpastes can result in the absorption of fluoride into the sealant. The objective of the present study was to assess the fluoride release/uptake capacities of different fissure sealants. Three different fissure sealants (Fuji Triage/GC, Fissurit FX/Voco and Grandio Seal/Voco) were examined. Ten discs of each material were prepared. Each disc was incubated with distilled water and then the solution analyzed for diluted for fluoride concentration, using a combination of fluoride electrode (OrionGP 1 S/N 13824, Orion Research Inc, Boston, MA, USA) connected to an expandable ion analyzer (Orion 720A, Orion Research Inc, Boston, MA, USA). Standard curves between 1 and 100 ppm F- were used to calibrate the electrode. Cumulative fluoride release was measured on days 1, 2, 3, 5, 7, 21, 35 and 49, then two different fluoride varnishes/pastes (Profluorid Varnish/Voco, MI Paste Plus/GC), were applied to the sealants tested, and fluoride release (after reuptake) was measured on days 56, 70 and 84. Kruskal Wallis test confirmed significant differences in fluoride release between Fuji Triage/GC and Fissurit FX/Voco and Grandio Seal/Voco from day 1 (P < 0.001). The application of fluoride varnish Profluorid Varnish enhanced the fluoride release for all sealants (P < 0.05). MI Paste Plus enhanced the fluoride release for all sealants except for Fuji Triage/GC (P > 0.05). The GIC-based sealant (Fuji Triage/GC) released significantly more fluoride than the resin sealants tested. The exposure to the fluoridated varnish (Profluorid Varnish) significantly recharged the sealants tested more than the CPP-ACPF toothpaste (MI Paste Plus). Fissure sealants, fluoride release, fluoride uptake, glass ionomer cements.

  11. Injectabilite des coulis de ciment dans des milieux fissures

    NASA Astrophysics Data System (ADS)

    Mnif, Thameur

    Le travail presente ici est un bilan du travaux de recherche effectues sur l'injectabilite des coulis de ciment dans lu milieux fissures. Un certain nombre de coulis a base de ciment Portland et microfin ont ete selectionnes afin de caracteriser leur capacite a penetrer des milieux fissures. Une partie des essais a ete menee en laboratoire. L'etude rheologique des differents melanges a permis de tester l'influence de l'ajout de superplastifiant et/ou de fumee de silice sur la distribution granulometrique des coulis et par consequent sur leur capacite a injecter des colonnes de sable simulant un milieu fissure donne. La classe granulometrique d'un coulis, sa stabilite et sa fluidite sont apparus comme les trois facteurs principaux pour la reussite d'une injection. Un facteur de finesse a ete defini au cours de cette etude: base sur la classe granulometrique du ciment et sa stabilite, il peut entrer dans la formulation theorique du debit d'injection avant application sur chantier. La deuxieme et derniere partie de l'etude presente les resultats de deux projets de recherche sur l'injection realises sur chantier. L'injection de dalles de beton fissurees a permis le suivi de l'evolution des pressions avec la distance au point d'injection. L'injection de murs de maconnerie a caractere historique a montre l'importance de la definition de criteres de performance des coulis a utiliser pour traiter un milieu donne et pour un objectif donne. Plusieurs melanges peuvent ainsi etre predefinis et mis a disposition sur le chantier. La complementarite des ciments traditionnels et des ciments microfins devient alors un atout important. Le choix d'utilisation de ces melanges est fonction du terrain rencontre. En conclusion, cette recherche etablit une methodologie pour la selection des coulis a base de ciment et des pressions d'injection en fonction de l'ouverture des fissures ou joints de construction.

  12. Location of seismic events and eruptive fissures on the Piton de la Fournaise volcano using seismic amplitudes

    USGS Publications Warehouse

    Battaglia, J.; Aki, K.

    2003-01-01

    We present a method for locating the source of seismic events on Piton de la Fournaise. The method is based on seismic amplitudes corrected for station site effects using coda site amplification factors. Once corrected, the spatial distribution of amplitudes shows smooth and simple contours for many types of events, including rockfalls, long-period events and eruption tremor. On the basis of the simplicity of these distributions we develop inversion methods for locating their origins. To achieve this, the decrease of the amplitude as a function of the distance to the source is approximated by the decay either of surface or body waves in a homogeneous medium. The method is effective for locating rockfalls, long-period events, and eruption tremor sources. The sources of eruption tremor are usually found to be located at shallow depth and close to the eruptive fissures. Because of this, our method is a useful tool for locating fissures at the beginning of eruptions.

  13. Surface fissures in articular cartilage: new concepts, hypotheses and modeling.

    PubMed

    Kafka, Vratislav

    2002-01-01

    Clarification and mesomechanical modeling of the inception of fissures at the surface of articular cartilage. Articular cartilage is described as a macroscopically heterogeneous medium consisting of zones - layers - with different orientation of collagen fibers. Degradation of mechanical properties of cartilage is a serious, still not fully clarified problem that deserves attention. Theoretical analysis based on a survey of known experimental findings related to the subject. The general author's mesomechanical concept of modeling heterogeneous media is applied to the elucidation and description of the formation of fissures at the surface of articular cartilage. Our model clarifies how the high tensile stresses in the collagen fibers of the superficial tangential zone depend on the rate of loading. The superficial cracks are caused predominantly by a very quick loading. This explains among others the high incidence of post-traumatic osteoarthritis of the lower extremity after accidents and injuries in sports. Superficial fissures in articular cartilage are observed in joints with primary osteoarthritis. The current study specifies the kinds of loading that lead to their inception.

  14. Fissurectomy as a treatment for anal fissures in children.

    PubMed Central

    Lambe, G. F.; Driver, C. P.; Morton, S.; Turnock, R. R.

    2000-01-01

    INTRODUCTION: Anal fissures, characterised by painful defecation and rectal bleeding, are common in both children and infants. A significant proportion are resistant to simple laxative therapy, and no simple surgical treatment has been described which does not risk compromising sphincteric function. This study reports the initial experience of fissurectomy as a treatment of this condition. PATIENTS AND METHODS: Over a 36 month period, 37 children with an anal fissure were treated by fissurectomy. There were 14 boys and 23 girls, with an age range of 17 weeks to 12 years. Fissurectomy was performed under general anaesthetic, with additional caudal anaesthesia. Stay sutures were used to avoid the need for an anal retractor, thereby preventing stretching of the internal anal sphincter. Of the 37 operations, 36 (97%) were performed as day cases and all children were discharged on laxative therapy. RESULTS: At review, 6 weeks postoperatively, 30 (81%) were asymptomatic. Six (16%) patients were symptomatic; however, 4 of these had failed to comply with the postoperative laxative regimen. One patient failed follow-up. CONCLUSIONS: Fissurectomy is a successful treatment for anal fissures, when combined with postoperative laxative therapy. As dilatation of the internal anal sphincter is not involved, the risk of iatrogenic faecal incontinence is obviated. Images Figure 1 Figure 2 Figure 3 PMID:10932659

  15. VOC transport in vented drums containing simulated waste sludge

    SciTech Connect

    Liekhus, K.J.; Gresham, G.L.; Rae, C.; Connolly, M.J.

    1994-02-01

    A model is developed to estimate the volatile organic compound (VOC) concentration in the headspace of the innermost layer of confinement in a lab-scale vented waste drum containing simulated waste sludge. The VOC transport model estimates the concentration using the measured VOC concentration beneath the drum lid and model parameters defined or estimated from process knowledge of drum contents and waste drum configuration. Model parameters include the VOC diffusion characteristic across the filter vent, VOC diffusivity in air, size of opening in the drum liner lid, the type and number of layers of polymer bags surrounding the waste, VOC permeability across the polymer, and the permeable surface area of the polymer bags. Comparison of model and experimental results indicates that the model can accurately estimate VOC concentration in the headspace of the innermost layer of confinement. The model may be useful in estimating the VOC concentration in actual waste drums.

  16. Assessing the atmospheric and climatic effects of basaltic fissure eruptions. A case study Nornahraun, North Iceland, 2014-2015.

    NASA Astrophysics Data System (ADS)

    Gallagher, Catherine; Burton, Kevin; Thordarson, Thorvaldur; Vye-Brown, Charlotte; Brown, Richard

    2015-04-01

    A volcanic eruption's ability to release sulphur gases into the atmosphere is one of the critical factors in assessing their climatic and environmental effects, because it is directly linked to the potential H2SO4 aerosol burden produced [1]. Basaltic fissure eruptions loft large amounts of sulphur into the atmosphere because of the efficient degassing of volatiles and halogens from the magma at the vent [2-4] coupled with the high sulphur yield of basaltic magma. The common nature of this style of eruption and its products, regardless of magnitude, means that our understanding of the exact processes which influence atmospheric chemistry and environmental impact is very important. The Nornahraun fissure eruption in North Iceland that began on the 31st August 2014, has quickly become one of the best documented eruptions of its kind, through systematic monitoring and sampling by the Institute of Earth Sciences eruption team and The Icelandic Meteorological Office. As a result it is an excellent modern analogue for historic or ancient basaltic fissure eruptions, for which the amount of degassing can only be estimated through petrological and geochemical methods. It also serves as a timely testing platform for novel geochemical proxies. This study uses the exceptional sensitivity of the 187Os-187Re radiogenic system to the presence of crustal material [5], and highly siderophile stable isotopes Cu, Zn and S to indicate the chemistry and degassing of the melt carrying S to the surface. The geochemical isotopic proxies will be tested using established petrological methods and gas emission data. This study concentrates on determining the following key parameters: (1) The source of volatiles in the magma indicated though the pressure dependence of S solubility. (2) The mechanism of aerosol and gas release into the atmosphere is dictated both by the chemistry of the melt that controls the S species (H2S, SO2 or FeS2) present [6], and by the mechanism of transfer. (3) The

  17. Geological and hydrothermal controls on the distribution of megafauna in Ashes Vent Field, Juan de Fuca Ridge

    NASA Astrophysics Data System (ADS)

    Arquit, Anne M.

    1990-08-01

    A computerized data base was constructed to aid in the interpretation of biological and geological observations recorded from 7662 photographs taken of Ashes vent field (located along the SW wall of the summit caldera of Axial Volcano, Juan de Fuca Ridge) during 1985-1986 using the Pisces IV submersible and a towed camera system. The transition region between the locus of high-temperature vents in Ashes vent field (i.e., Inferno, 326°C; Hell, 301°C; and Virgin Mound, 298°C) and more typical environmental conditions for the summit caldera of Axial Volcano as a whole is zoned spatially with respect to sediment type and organism assemblage. Three general ecological zones are identified within the vent field: (1) the central vent zone (within 100 m of a high-temperature vent), dominated by vent-associated organisms (vestimentiferan tube worms, clams, bacterial mats) and sedimentation (high-temperature, plume-derived and low-temperature, in situ deposits); (2) the distal vent zone (100-725 m from any high-temperature vent), characterized by extensive fields of iron oxide, iron silicate and silica chimneys and sediment (nontronite assemblage material), as well as maximum densities of most nonvent fauna; and (3) the nonvent impact zone (725-1300 m), indicated by elevated densities of nonvent organisms relative to regional (i.e., caldera-wide) values and maximum Bathydorus sp. sponge densities. The distribution of vestimentiferan tube worms is limited to within 90 m of known high-temperature venting (central vent zone); and anemones were observed only between 30 and 40 m from hot vents. Clams and microbial mats are concentrated in the central vent zone, as well, but occur sporadically up to 1250 m from the hot vents in association with hydrothermal nontronite that is probably precipitating in situ from <60°C vent fluid; thus megafaunal distributions are a useful indicator of poorly defined, often diffuse low-temperature hydrothermal activity on the seafloor. Maximum

  18. 46 CFR 153.358 - Venting system flow capacity.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Venting system flow capacity. 153.358 Section 153.358... CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Venting Systems § 153.358 Venting system flow capacity. (a) The cross-sectional flow area of any vent...

  19. 46 CFR 153.358 - Venting system flow capacity.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Venting system flow capacity. 153.358 Section 153.358... CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Venting Systems § 153.358 Venting system flow capacity. (a) The cross-sectional flow area of any vent...

  20. 46 CFR 153.358 - Venting system flow capacity.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Venting system flow capacity. 153.358 Section 153.358 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS... Venting Systems § 153.358 Venting system flow capacity. (a) The cross-sectional flow area of any vent...

  1. 24 CFR 3280.710 - Venting, ventilation and combustion air.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 5 2011-04-01 2011-04-01 false Venting, ventilation and combustion... Fuel Burning Systems § 3280.710 Venting, ventilation and combustion air. (a) The venting as required by... appliance listing and the appliance manufacturer's instructions. (b) Venting and combustion air...

  2. 24 CFR 3280.710 - Venting, ventilation and combustion air.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Venting, ventilation and combustion... Fuel Burning Systems § 3280.710 Venting, ventilation and combustion air. (a) The venting as required by... appliance listing and the appliance manufacturer's instructions. (b) Venting and combustion air...

  3. 24 CFR 3280.710 - Venting, ventilation and combustion air.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 5 2014-04-01 2014-04-01 false Venting, ventilation and combustion... Fuel Burning Systems § 3280.710 Venting, ventilation and combustion air. (a) The venting as required by... appliance listing and the appliance manufacturer's instructions. (b) Venting and combustion air systems...

  4. 24 CFR 3280.710 - Venting, ventilation and combustion air.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 5 2013-04-01 2013-04-01 false Venting, ventilation and combustion... Fuel Burning Systems § 3280.710 Venting, ventilation and combustion air. (a) The venting as required by... appliance listing and the appliance manufacturer's instructions. (b) Venting and combustion air systems...

  5. 14 CFR 125.159 - Vent and drain lines.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Vent and drain lines. 125.159 Section 125... Requirements § 125.159 Vent and drain lines. All vent and drain lines, and their fittings, that are located in... Administrator finds that the rupture or breakage of any vent or drain line may result in a fire hazard. ...

  6. 46 CFR 153.355 - PV venting systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false PV venting systems. 153.355 Section 153.355 Shipping... Systems § 153.355 PV venting systems. When Table 1 requires a PV venting system, the cargo tank must have a PV valve in its vent line. The PV valve must be located between the tank and any connection to...

  7. 46 CFR 153.355 - PV venting systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false PV venting systems. 153.355 Section 153.355 Shipping... Systems § 153.355 PV venting systems. When Table 1 requires a PV venting system, the cargo tank must have a PV valve in its vent line. The PV valve must be located between the tank and any connection to...

  8. The fissure: interlobar collateral ventilation and implications for endoscopic therapy in emphysema

    PubMed Central

    Koster, Theodoor David; Slebos, Dirk-Jan

    2016-01-01

    In patients with severe emphysema, bronchoscopic lung volume reduction using one-way valves is a promising therapeutic option to improve lung function and quality of life. The goal of this treatment is to achieve a complete lobar atelectasis. In a significant proportion of patients, this atelectasis cannot be achieved due to interlobar collateral ventilation. This collateral ventilation is generated through incomplete lobar fissures. Therefore, only patients with complete fissures and no collateral ventilation can be selected for endobronchial therapy with one-way valves. Incomplete fissures are very common and exhibit a great variation in anatomy. The reported prevalence is 17%–85% for the right major fissure, 19%–74% for the left major fissure, and 20%–90% for the minor fissure. There are several methods of measuring or predicting the presence of collateral ventilation, with computed tomography (CT)-fissure analysis and the Chartis measurement being the most important. CT-fissure analysis is an indirect method to measure the completeness of fissures as a surrogate for collateral ventilation. The Chartis system is an endobronchial method to directly measure the presence of collateral ventilation. Both methods have unique value, and the combination of both can accurately predict the treatment response to the bronchoscopic placement of endobronchial valves. This review provides an in-depth view of lung fissure and collateral ventilation to help understand its importance in selecting the appropriate patients for new emphysema treatments and thus avoid useless treatment in unsuitable patients. PMID:27110109

  9. The fissure: interlobar collateral ventilation and implications for endoscopic therapy in emphysema.

    PubMed

    Koster, Theodoor David; Slebos, Dirk-Jan

    2016-01-01

    In patients with severe emphysema, bronchoscopic lung volume reduction using one-way valves is a promising therapeutic option to improve lung function and quality of life. The goal of this treatment is to achieve a complete lobar atelectasis. In a significant proportion of patients, this atelectasis cannot be achieved due to interlobar collateral ventilation. This collateral ventilation is generated through incomplete lobar fissures. Therefore, only patients with complete fissures and no collateral ventilation can be selected for endobronchial therapy with one-way valves. Incomplete fissures are very common and exhibit a great variation in anatomy. The reported prevalence is 17%-85% for the right major fissure, 19%-74% for the left major fissure, and 20%-90% for the minor fissure. There are several methods of measuring or predicting the presence of collateral ventilation, with computed tomography (CT)-fissure analysis and the Chartis measurement being the most important. CT-fissure analysis is an indirect method to measure the completeness of fissures as a surrogate for collateral ventilation. The Chartis system is an endobronchial method to directly measure the presence of collateral ventilation. Both methods have unique value, and the combination of both can accurately predict the treatment response to the bronchoscopic placement of endobronchial valves. This review provides an in-depth view of lung fissure and collateral ventilation to help understand its importance in selecting the appropriate patients for new emphysema treatments and thus avoid useless treatment in unsuitable patients.

  10. Catalytic Diversity in Alkaline Hydrothermal Vent Systems on Ocean Worlds

    NASA Astrophysics Data System (ADS)

    Cameron, Ryan D.; Barge, Laura; Chin, Keith B.; Doloboff, Ivria J.; Flores, Erika; Hammer, Arden C.; Sobron, Pablo; Russell, Michael J.; Kanik, Isik

    2016-10-01

    Hydrothermal systems formed by serpentinization can create moderate-temperature, alkaline systems and it is possible that this type of vent could exist on icy worlds such as Europa which have water-rock interfaces. It has been proposed that some prebiotic chemistry responsible for the emergence of life on Earth and possibly other wet and icy worlds could occur as a result ofredox potential and pH gradients in submarine alkaline hydrothermal vents (Russell et al., 2014). Hydrothermal chimneys formed in laboratory simulations of alkaline vents under early Earth conditions have precipitate membranes that contain minerals such as iron sulfides, which are hypothesized to catalyze reduction of CO2 (Yamaguchi et al. 2014, Roldan et al. 2014) leading to further organic synthesis. This CO2 reduction process may be affected by other trace components in the chimney, e.g. nickel or organic molecules. We have conducted experiments to investigate catalytic properties of iron and iron-nickel sulfides containing organic dopants in slightly acidic ocean simulants relevant to early Earth or possibly ocean worlds. We find that the electrochemical properties of the chimney as well as the morphology/chemistry of the precipitate are affected by the concentration and type of organics present. These results imply that synthesis of organics in water-rock systems on ocean worlds may lead to hydrothermal precipitates which can incorporate these organic into the mineral matrix and may affect the role of gradients in alkaline vent systems.Therefore, further understanding on the electroactive roles of various organic species within hydrothermal chimneys will have important implications for habitability as well as prebiotic chemistry. This work is funded by NASA Astrobiology Institute JPL Icy Worlds Team and a NAI Director's Discretionary Fund award.Yamaguchi A. et al. (2014) Electrochimica Acta, 141, 311-318.Russell, M. J. et al. (2014), Astrobiology, 14, 308-43.Roldan, A. (2014) Chem. Comm. 51

  11. Hydrogen venting characteristics of commercial carbon-composite filters and applications to TRU waste

    SciTech Connect

    Callis, E.L.; Marshall, R.S.; Cappis, J.H.

    1997-04-01

    The generation of hydrogen (by radiolysis) and of other potentially flammable gases in radioactive wastes which are in contact with hydrogenous materials is a source of concern, both from transportation and on-site storage considerations. Because very little experimental data on the generation and accumulation of hydrogen was available in actual waste materials, work was initiated to experimentally determine factors affecting the concentration of hydrogen in the waste containers, such as the hydrogen generation rate, (G-values) and the rate of loss of hydrogen through packaging and commercial filter-vents, including a new design suitable for plastic bags. This report deals only with the venting aspect of the problem. Hydrogen venting characteristics of two types of commercial carbon-composite filter-vents, and two types of PVC bag closures (heat-sealed and twist-and-tape) were measured. Techniques and equipment were developed to permit measurement of the hydrogen concentration in various layers of actual transuranic (TRU) waste packages, both with and without filter-vents. A test barrel was assembled containing known configuration and amounts of TRU wastes. Measurements of the hydrogen in the headspace verified a hydrogen release model developed by Benchmark Environmental Corporation. These data were used to calculate revised wattage Emits for TRU waste packages incorporating the new bag filter-vent.

  12. Diverse styles of submarine venting on the ultraslow spreading Mid-Cayman Rise

    PubMed Central

    German, C. R.; Bowen, A.; Coleman, M. L.; Honig, D. L.; Huber, J. A.; Jakuba, M. V.; Kinsey, J. C.; Kurz, M. D.; Leroy, S.; McDermott, J. M.; de Lépinay, B. Mercier; Nakamura, K.; Seewald, J. S.; Smith, J. L.; Sylva, S. P.; Van Dover, C. L.; Whitcomb, L. L.; Yoerger, D. R.

    2010-01-01

    Thirty years after the first discovery of high-temperature submarine venting, the vast majority of the global mid-ocean ridge remains unexplored for hydrothermal activity. Of particular interest are the world’s ultraslow spreading ridges that were the last to be demonstrated to host high-temperature venting but may host systems particularly relevant to prebiotic chemistry and the origins of life. Here we report evidence for previously unknown, diverse, and very deep hydrothermal vents along the ∼110 km long, ultraslow spreading Mid-Cayman Rise (MCR). Our data indicate that the MCR hosts at least three discrete hydrothermal sites, each representing a different type of water-rock interaction, including both mafic and ultramafic systems and, at ∼5,000 m, the deepest known hydrothermal vent. Although submarine hydrothermal circulation, in which seawater percolates through and reacts with host lithologies, occurs on all mid-ocean ridges, the diversity of vent types identified here and their relative geographic isolation make the MCR unique in the oceans. These new sites offer prospects for an expanded range of vent-fluid compositions, varieties of abiotic organic chemical synthesis and extremophile microorganisms, and unparalleled faunal biodiversity—all in close proximity. PMID:20660317

  13. Diverse styles of submarine venting on the ultraslow spreading Mid-Cayman Rise.

    PubMed

    German, C R; Bowen, A; Coleman, M L; Honig, D L; Huber, J A; Jakuba, M V; Kinsey, J C; Kurz, M D; Leroy, S; McDermott, J M; de Lépinay, B Mercier; Nakamura, K; Seewald, J S; Smith, J L; Sylva, S P; Van Dover, C L; Whitcomb, L L; Yoerger, D R

    2010-08-10

    Thirty years after the first discovery of high-temperature submarine venting, the vast majority of the global mid-ocean ridge remains unexplored for hydrothermal activity. Of particular interest are the world's ultraslow spreading ridges that were the last to be demonstrated to host high-temperature venting but may host systems particularly relevant to prebiotic chemistry and the origins of life. Here we report evidence for previously unknown, diverse, and very deep hydrothermal vents along the approximately 110 km long, ultraslow spreading Mid-Cayman Rise (MCR). Our data indicate that the MCR hosts at least three discrete hydrothermal sites, each representing a different type of water-rock interaction, including both mafic and ultramafic systems and, at approximately 5,000 m, the deepest known hydrothermal vent. Although submarine hydrothermal circulation, in which seawater percolates through and reacts with host lithologies, occurs on all mid-ocean ridges, the diversity of vent types identified here and their relative geographic isolation make the MCR unique in the oceans. These new sites offer prospects for an expanded range of vent-fluid compositions, varieties of abiotic organic chemical synthesis and extremophile microorganisms, and unparalleled faunal biodiversity--all in close proximity.

  14. Lava-flow hazard with optimized non-uniform grid of vents

    NASA Astrophysics Data System (ADS)

    Lucà, Federica; Rongo, Rocco; Lupiano, Valeria; Iovine, Giulio

    2016-10-01

    The aim of the study is to assess the sensitivity to vents (in terms of number and distribution) of sectors affected by lava flows and of hazard values at Mount Etna. The proposed methodology relies on the application of the Cellular Automata model SCIARA, and on the adoption of an optimization algorithm for progressively integrating an initial uniform distribution of 1006 vents (1-km spaced) with 500 additional sources. Vents have iteratively been added, at steps of 50, through spatial simulated annealing, using slope roughness as weigh function. For each vent, 41 types of simulations have been executed to take into proper account the potential behaviour of the volcano, based on historical records. The performed simulations have been further processed to derive lava-flow hazard, by assigning each simulation: i) a spatial likelihood of vent opening; ii) a magnitude probability, depending on the type of eruption; and iii) a temporal probability of source activation, based on historical occurrences in the past 400 years. First results are discussed, and the influence of the number and distribution of additional vents is preliminarily investigated.

  15. Anterior anal fissures are associated with occult sphincter injury and abnormal sphincter function.

    PubMed

    Jenkins, J T; Urie, A; Molloy, R G

    2008-03-01

    The pathogenesis of chronic anal fissure (CAF) remains incompletely understood but most are associated with a high resting anal pressure and reduced perfusion at the fissure site. To date, no major distinction has been made between anterior and posterior anal fissures and their aetiology and treatment. We compared anterior and posterior fissures in patients who have failed to respond to medical treatment with respect to their underlying aetiology, anal canal pressures and sphincter muscle integrity. Seventy consecutive patients (54 female:16 male) with a symptomatic CAF and 39 normal controls (19 female:20 male) without evidence of significant ano-rectal pathology were prospectively assessed by manometry and anal endosonography. Anterior anal fissures were identified in a younger age group [33 years (IQR 26-37) vs 41 years (IQR 36-52)] and predominantly in women. Anterior fissure patients were significantly more likely to have underlying external anal sphincter defects compared with posterior fissures [OR 10.9 (95% CI 3.4-35.4)]. Maximum resting pressure was not significantly elevated for anterior fissures compared with controls (P = 0.316) but was significantly elevated in posterior fissures (P = 0.005). The maximum squeeze pressure was significantly lower in the anterior fissure group [167 cmH2O (IQR 126-196) vs 205 cmH2O (IQR 174-262), P = 0.004]. A history of obstetric trauma was significantly associated with anterior fissure location [OR 13.9 (95% CI 3.4-55.7)]. Anterior anal fissures are associated with occult external anal sphincter injury and impaired external anal sphincter function compared with posterior fissures. These findings have implications for treatment, especially if a definitive procedure, such as lateral internal sphincterotomy, is considered.

  16. The effects of opaque and clear pit and fissure sealants on infrared laser fluorescence measurements.

    PubMed

    Bahrololoomi, Z; Khodabakhsh, M; Khaksar, Y

    2014-06-01

    The purpose of placing sealants is to inhibit caries by physical closure of the pits and fissures of teeth. A device named DIAGNOdent is useful in detecting occlusal caries by employing laser fluorescence (LF). However, there are contradictory results in the influence of sealants on LF measurements. The aim of this study is to investigate the effects of two different types of fissure sealants on LF measurements. In this in vitro study, 86 extracted permanent third molars were divided randomly into two groups and clear or opaque sealant was applied on the occlusal surfaces. Two examiners performed pre- and post-seal fluorescence measurements twice with one week interval by employing DIAGNOdent device. Finally, measured values were evaluated through the statistical paired t-test by means of SPSS 17 software. The mean value of LF measurements increased significantly due to the application of clear sealant (p= 0.001) while the statistical changes in this measurement was negligible after applying opaque sealant (p= 0.311). Clear sealants increase the LF measured values but opaque sealants cause almost no changes. Therefore, DIAGNOdent device is not reliable for detecting caries beneath the clear sealant.

  17. The Effects of Opaque and Clear Pit and Fissure Sealants on Infrared Laser Fluorescence Measurements

    PubMed Central

    Bahrololoomi, Z.; Khodabakhsh, M.; Khaksar, Y.

    2014-01-01

    Statement of the Problem: The purpose of placing sealants is to inhibit caries by physical closure of the pits and fissures of teeth. A device named DIAGNOdent is useful in detecting occlusal caries by employing laser fluorescence (LF). However, there are contradictory results in the influence of sealants on LF measurements. Purpose: The aim of this study is to investigate the effects of two different types of fissure sealants on LF measurements. Materials and Method: In this in vitro study, 86 extracted permanent third molars were divided randomly into two groups and clear or opaque sealant was applied on the occlusal surfaces. Two examiners performed pre- and post-seal fluorescence measurements twice with one week interval by employing DIAGNOdent device. Finally, measured values were evaluated through the statistical paired t-test by means of SPSS 17 software. Results: The mean value of LF measurements increased significantly due to the application of clear sealant (p= 0.001) while the statistical changes in this measurement was negligible after applying opaque sealant (p= 0.311). Conclusion: Clear sealants increase the LF measured values but opaque sealants cause almost no changes. Therefore, DIAGNOdent device is not reliable for detecting caries beneath the clear sealant. PMID:24883342

  18. Wear of two pit and fissure sealants in contact with primary teeth

    PubMed Central

    Galo, Rodrigo; Contente, Marta Maria Martins Giamatei; Borsatto, Maria Cristina

    2014-01-01

    Objectives: Wear simulations may provide an indication of the clinical performance of pit-and-fissure sealants when associated with primary teeth as counterbody, restricting the involved variables. The aim of this study was to evaluate wear of dental materials used as pit-and-fissure sealants in contact with primary teeth. Materials and Methods: A resinous sealant (Fluroshield®) and a resin-modified glass ionomer cement (Vitremer®) were selected in a post-plate design, using as counterbody primary tooth pins (4 × 4 × 2 mm) at 3 and 10 N vertical load, 1 Hz frequency, 900 wear cycles in artificial saliva (n = 15). Attrition coefficient values were obtained and the material and primary tooth volumes were analyzed. Data were analyzed statistically by ANOVA and Duncan's test (P < 0.05). Results: Fluroshield® presented the highest attrition coefficient values for the 3 N but these values decreased significantly for the 10 N load. The means for volume loss (3 mm) of the different samples after the wear test were not statistically different for the materials. The volume loss values for the primary teeth were statistically different and there was an increase in volume loss with the increase of the load applied in the wear tests. Conclusions: Differences were also observed with regard to the surface deformation characteristics. The wear rates of primary tooth enamel vary according to the type of material and the load applied during mastication. PMID:24966777

  19. Le Fort I osteotomy to enucleation of grand proportions fissural cyst-presentation of case report.

    PubMed

    Cavalcante, Rafael Correia; Durski, Fernanda; Deliberador, Tatiana Miranda; Giovanini, Allan Fernando; Rebellato, Nelson Luís Barbosa; da Costa, Delson João; Klüppel, Leandro Eduardo; Scariot, Rafaela

    2016-01-01

    Fissural cysts (FC) are caused by entraped epithelium between nasal and maxilar processes. They are commonly treated with surgical enucleation precedded or not by marsupialization depending on the cyst size. Biopsy of lesion is recommended due to confirm radiographic evaluation. It is rare to observe Le Fort I surgical approach to this type of injury. This study reports the case of an uncommon grand proportions fissural cyst in a female patient, 53, that was referred to the Oral and Maxillofacial Surgery Departament of Hospital XV presenting volume increase in maxilla associated with numbness of palate. Radiograph examination showed an intimate relationship between incisors apexes and FC. Expansion of both buccal and palate cortical was then confirmed as well as its unusual size, approximately 25 millimeters. Due to the abnormal size of lesion and possible impairment of upper incisors, LeFort I osteotomy associated with downfracture to cystic enucleation was the chosen treatment. After enucleation, the remaining space was filled with BIOSs and bioguide (lyophilized bone and collagen membrane). Patients' twelve months follow-up demonstrate no relapses and maintenance of teeth involved.

  20. External Tank GH2 Vent Arm

    NASA Technical Reports Server (NTRS)

    Reichle, G. E.; Glassburn, C. W.

    1985-01-01

    Because the venting of free hydrogen gas to the atmosphere presents an extremely hazardous situation, it was necessary to devise a means for safe, controlled venting of the shuttle external tank gaseous hydrogen during and after liquid hydrogen tank loading. Several design concepts that were considered initially were discarded as unfeasible because of vehicle weight restrictions, high cost, and because the proposed structure was itself deemed a hazard due to the vehicle's nonvertical launch trajectory. These design concepts are discussed. A design employing a support structure/access arm attached to the fixed service structure was finally selected. The various design problems resolved included vent arm disconnect/drop interference, minimizing refurbishment due to launch damage, disconnect reliability, vehicle movement tracking, minimizing vent line pressure drop, and the presence of other vehicle services at the same centralized supply area. Six launches have proven the system to be reliable, efficient, and of nearly zero refurbishment cost.

  1. The geochemical controls on vent fluids from the Lucky Strike vent field, Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Von Damm, K. L.; Bray, A. M.; Buttermore, L. G.; Oosting, S. E.

    1998-08-01

    Hydrothermal vent fluids were collected from the Lucky Strike site at 37°17'N on the Mid-Atlantic Ridge in both 1993 and 1996. Seven vents were sampled with the DSV Alvin in 1993 and six vents were sampled in 1996 using the ROV Jason during the LUSTRE '96 Cruise. As three of the vents were sampled in both 1993 and in 1996, a time series of vent fluid chemistry is also reported. Measured temperatures ranged from 202 to 333°C at the 1618-1726 m depth of the vent field, which is located on Lucky Strike Seamount. These fluids are either equal to or less than the local bottom seawater in chlorinity. While the range in fluid compositions at Lucky Strike is generally within that observed elsewhere, the unusual aspects of the fluid chemistries are the relatively high pH and low Fe, Mn, Li and Zn. We attribute this, as well as an usually low Sr/Ca ratio, to reaction with a highly altered substrate. The high Si and Cu contents suggest a deep, as well as hot, source for these fluids. The fluid compositions therefore suggest formation by super-critical phase separation at a depth not less than 1300 m below the seafloor, and reaction with a relatively oxic, and previously altered, substrate. There is temporal variability in some of the vent fluid compositions as Li, K, Ca and Fe concentrations have increased in some of the vents, as has the Fe/Mn (molar) ratio, although the chlorinities have remained essentially constant from 1993 to 1996. While there is not a simple relationship between vent fluid compositions (or temperatures) and distance from the lava lake at the summit of the seamount, the vent fluids from many of the vents can be shown to be related to others, often at distances >200 m. The most southeasterly vents (Eiffel Tower and the Marker/Mounds vents) are distinct in chlorinity and other chemical parameters from the rest of the vents, although closely related to each other within the southeastern area. Similarly all of the vents not in this one area, appear

  2. Three-armed rifts or masked radial pattern of eruptive fissures? The intriguing case of El Hierro volcano (Canary Islands)

    NASA Astrophysics Data System (ADS)

    Becerril, L.; Galindo, I.; Martí, J.; Gudmundsson, A.

    2015-04-01

    Using new surface structural data as well as subsurface structural data obtained from seventeen water galleries, we provide a comprehensive model of the volcano-tectonic evolution of El Hierro (Canary Islands). We have identified, measured and analysed more than 1700 volcano-structural elements including vents, eruptive fissures, dykes and faults. The new data provide important information on the main structural patterns of the island and on its stress and strain fields, all of which are crucial for reliable hazard assessments. We conducted temporal and spatial analyses of the main structural elements, focusing on their relative age and association with the three main cycles in the construction of the island: the Tiñor Edifice, the El Golfo-Las Playas Edifice, and the Rift Volcanism. A radial strike distribution, which can be related to constructive episodes, is observed in the on-land structures. A similar strike distribution is seen in the submarine eruptive fissures, which are radial with respect to the centre of the island. However, the volcano-structural elements identified onshore and reflecting the entire volcano-tectonic evolution of the island also show a predominant NE-SW strike, which coincides with the main regional trend of the Canary archipelago as a whole. Two other dominant directions of structural elements, N-S and WNW-ESE, are evident from the establishment of the El Golfo-Las Playas edifice, during the second constructive cycle. We suggest that the radial-striking structures reflect comparatively uniform stress fields during the constructive episodes, mainly conditioned by the combination of overburden pressure, gravitational spreading, and magma-induced stresses in each of the volcanic edifices. By contrast, in the shallower parts of the edifice the NE-SW, N-S and WNW-ESE-striking structures reflect local stress fields related to the formation of mega-landslides and masking the general and regional radial patterns.

  3. VentDB: A Global Online Synthesis Database of Seafloor Hydrothermal Spring Geochemistry

    NASA Astrophysics Data System (ADS)

    Mottl, M. J.; Lehnert, K. A.; Johansson, A. K.; Hsu, L.

    2011-12-01

    Chemical data for seafloor hydrothermal springs are fundamental to the study of mid-ocean ridge and seafloor processes, ocean water chemistry, and global geochemical cycles, as well as vent ecosystems and the sub-seafloor biosphere. So far, these data have been accessible only in the scientific literature or in online data catalogs where they are widely dispersed in individual data tables, and are often insufficiently documented for re-use. We have developed VentDB as an online data system for geochemical data for hydrothermal springs that will facilitate access and analysis of these data. VentDB uses the concept and architecture of the popular PetDB database for seafloor igneous and metamorphic rock geochemistry (www.petdb.org) to provide easy and fast access to a global synthesis of seafloor hydrothermal spring geochemical data. The VentDB database contains concentrations of major and trace species, dissolved gases, and radiogenic and isotopic ratios for hydrothermal vents on the seafloor. Further chemical or physical properties of hydrothermal springs can be included in the future if desired. The database comprises both the calculated hydrothermal end-member solution compositions as estimated by extrapolation of the concentrations of individual chemical species to a Mg concentration of zero, and the raw data for hydrothermal solution samples as collected, where available. Data quality is documented by including information for the raw analytical data about the analytical method, precision, and reference material measurements, and quality control parameters for end-member compositions including the lowest Mg measured in any sample, the number of samples and correlation coefficient of the linear regression, and the charge balance for the extrapolated zero-Mg composition. The database also includes information about the sampled locations (geospatial coordinates, vent or vent field names, names of other physiographic features), temperature, flow and vent type

  4. The vent microbiome: patterns and drivers

    NASA Astrophysics Data System (ADS)

    Pachiadaki, M.

    2015-12-01

    Microbial processes within deep-sea hydrothermal vents affect the global biogeochemical cycles. Still, there are significant gaps in our understanding of the microbiology and the biogeochemistry of deep-sea hydrothermal systems. Vents differ in temperature, host rock composition and fluid chemistry; factors that are hypothesized to shape the distribution of the microbial communities, their metabolic capabilities and their activities. Using large-scale single cell genomics, we obtained insights into the genomic content of several linkages of a diffuse flow vent. The genomes show high metabolic versatility. Sulfur oxidation appears to be predominant but there is the potential of using a variety of e- donors and acceptors to obtain energy. To further assess the ecological importance of the vent auto- and heterotrophs, the global biogeography of the analyzed lineages will be investigated by fragment recruitment of metagenomes produced from the same site as well as other hydrothermal systems. Metatranscriptomic and metaproteomic data will be integrated to examine the expression of the predominant metabolic pathways and thus the main energy sources driving chemoautotrophic production. The comparative analysis of the key players and associated pathways among various vent sites that differ in physicochemical characteristics is anticipated to decipher the patterns and drivers of the global dispersion and the local diversification of the vent microbiome.

  5. Explosion testing for the container venting system

    SciTech Connect

    Cashdollar, K.L.; Green, G.M.; Thomas, R.A.; Demiter, J.A.

    1993-09-30

    As part of the study of the hazards of inspecting nuclear waste stored at the Hanford Site, the US Department of Energy and Westinghouse Hanford Company have developed a container venting system to sample the gases that may be present in various metal drums and other containers. In support of this work, the US Bureau of Mines has studied the probability of ignition while drilling into drums and other containers that may contain flammable gas mixtures. The Westinghouse Hanford Company drilling procedure was simulated by tests conducted in the Bureau`s 8-liter chamber, using the same type of pneumatic drill that will be used at the Hanford Site. There were no ignitions of near-stoichiometric hydrogen-air or methane-air mixtures during the drilling tests. The temperatures of the drill bits and lids were measured by an infrared video camera during the drilling tests. These measured temperatures are significantly lower than the {approximately}500{degree}C autoignition temperature of uniformly heated hydrogen-air or the {approximately}600{degree}C autoignition temperature of uniformly heated methane-air. The temperatures are substantially lower than the 750{degree}C ignition temperature of hydrogen-air and 1,220{degree}C temperature of methane-air when heated by a 1-m-diameter wire.

  6. Shallow seismicity at open-vent volcanoes

    NASA Astrophysics Data System (ADS)

    Girona, T.; Caudron, C.; Huber, C.

    2016-12-01

    Understanding the origin of the shallow seismicity detected at active volcanoes is fundamental to interpret geophysical and geochemical signals in terms of sub-surface magmatic processes. One of the most intriguing seismic signals is shallow tremor, which is long-lasting (from minutes to months), is usually sourced at shallow levels ( 100's of meters), has dominant frequencies in the range 0.1-20 Hz, and is common to many open-vent and hydrothermal systems. Here, we present a viable mechanism to explain the origin of shallow tremor and its correlation with magma degassing. In particular, we show from basic principles (mass and momentum balance) that shallow tremor can emerge spontaneously as a result of three coupled processes: (1) the formation of gas pockets beneath rheological or geometrical barriers; (2) the intermittent supply of volatiles from depth, e.g., through a bubbly magma column; and (3) the permeable transfer of these gases through a porous lava dome, conduit, or volcanic edifice. Our model, which can be solved analytically at first order, reproduces and provides an explanation for the main features of shallow tremor, including frequency gliding, changes of seismic amplitude when volcanoes enter a period of unrest, and the different types of amplitude spectra observed (i.e., monochromatic, harmonic, and broadband). A crucial conclusion of our study is that different processes (e.g., magma ascent and sealing of gas pathways) cause distinguishable variations in the tremor properties, which could be used by monitoring agencies to improve volcanic forecasting.

  7. Enamel fusion using a carbon dioxide laser: A technique for sealing pits and fissures

    SciTech Connect

    Walsh, L.J.; Perham, S.J. )

    1991-05-01

    The well-established enhanced resistance of lased enamel to demineralization is the basis for clinical application of the carbon dioxide laser to caries prevention. This in vitro study examined the effect of focused infrared laser radiation on sound enamel and early pit and fissure caries. Low power levels (2-5 W) induced localized melting and resolidification of enamel with little surface destruction. For sound fissures, fusion of enamel from the lateral walls of the fissure eliminated the fissure space, providing a sealant effect; while in carious fissures, carious enamel was vaporized and adjacent sound enamel fused to partially eliminate the defect. The technique for enamel fusion using CO2 lasers has potential application for sealing pits and fissures and producing physicochemical alterations in enamel which may have preventive benefits.

  8. Abnormal vasculature interferes with optic fissure closure in lmo2 mutant zebrafish embryos.

    PubMed

    Weiss, Omri; Kaufman, Rivka; Michaeli, Natali; Inbal, Adi

    2012-09-15

    Ocular coloboma is a potentially blinding congenital eye malformation caused by failure of optic fissure closure during early embryogenesis. The optic fissure is a ventral groove that forms during optic cup morphogenesis, and through which hyaloid artery and vein enter and leave the developing eye, respectively. After hyaloid artery and vein formation, the optic fissure closes around them. The mechanisms underlying optic fissure closure are poorly understood, and whether and how this process is influenced by hyaloid vessel development is unknown. Here we show that a loss-of-function mutation in lmo2, a gene specifically required for hematopoiesis and vascular development, results in failure of optic fissure closure in zebrafish. Analysis of ocular blood vessels in lmo2 mutants reveals that some vessels are severely dilated, including the hyaloid vein. Remarkably, reducing vessel size leads to rescue of optic fissure phenotype. Our results reveal a new mechanism leading to coloboma, whereby malformed blood vessels interfere with eye morphogenesis.

  9. Cellular resolution optical access to brain regions in fissures: imaging medial prefrontal cortex and grid cells in entorhinal cortex.

    PubMed

    Low, Ryan J; Gu, Yi; Tank, David W

    2014-12-30

    In vivo two-photon microscopy provides the foundation for an array of powerful techniques for optically measuring and perturbing neural circuits. However, challenging tissue properties and geometry have prevented high-resolution optical access to regions situated within deep fissures. These regions include the medial prefrontal and medial entorhinal cortex (mPFC and MEC), which are of broad scientific and clinical interest. Here, we present a method for in vivo, subcellular resolution optical access to the mPFC and MEC using microprisms inserted into the fissures. We chronically imaged the mPFC and MEC in mice running on a spherical treadmill, using two-photon laser-scanning microscopy and genetically encoded calcium indicators to measure network activity. In the MEC, we imaged grid cells, a widely studied cell type essential to memory and spatial information processing. These cells exhibited spatially modulated activity during navigation in a virtual reality environment. This method should be extendable to other brain regions situated within deep fissures, and opens up these regions for study at cellular resolution in behaving animals using a rapidly expanding palette of optical tools for perturbing and measuring network structure and function.

  10. Thulium laser versus staplers for anatomic pulmonary resections with incomplete fissures: negative results of a randomized trial.

    PubMed

    Scanagatta, Paolo; Furia, Simone; Billè, Andrea; Duranti, Leonardo; Girelli, Lara; Tavecchio, Luca Domenico; Leo, Francesco; Giovannetti, Riccardo; Pelosi, Giuseppe; Porcu, Luca; Pastorino, Ugo

    2014-01-01

    This randomized trial evaluated the feasibility and safety of thulium 2010-nm laser to perform anatomic lung resections in patients with incomplete fissures, as compared to mechanical staplers with or without sealants. Seventy-two patients scheduled for segmentectomy or lobectomy were enrolled. After intraoperative confirmation of the extent of resection and incomplete fissures (Craig type 2, 3 or 4), they were randomized and allocated to one of the following arms: laser resection by thulium (group A) or standard resection with mechanical staplers with or without sealants (group B). The primary endpoints of the study included analysis of intraoperative and postoperative course, and costs. Thirty-eight patients were assigned to group A (32 lobectomies, 6 segmentectomies) and 34 to group B (31 lobectomies, 3 segmentectomies). No 30-day mortality was observed. Median operative times were 145.0 minutes (group A) and 142.5 minutes (group B, P = 0.83). The median time to drainage removal was 5 days (group A) and 4 days (group B), while the median length of hospital stay was the same (7 days). Prolonged air leaks >7 days were observed in 12 patients of group A (32%) and 10 patients of group B (29%, P = 0.46). Unpredictable late pneumothorax occurred in 3 patients of group A (2 readmissions, need for 1 repeat thoracotomy). Cost analysis demonstrated an intraoperative advantage for group A (mean 807 ± 212 euro) versus group B (mean 1,047+/-276 euro, P <0.0001), but the differences in total costs could be due to chance (P = 0.83). The use of laser to complete fissures can lead to late pneumothorax, even in the absence of postoperative air leaks. Moreover, the use of laser to complete fissures did not prove to reduce overall costs. Trial Registration Identification Number: 41/10 (IRB00001457 - FWA00001798 - IORG0001063).

  11. Surface anatomy of the pulmonary fissures determined by high-resolution computed tomography.

    PubMed

    Heřmanová, Zuzana; Ctvrtlík, Filip; Heřman, Miroslav

    2012-10-01

    The aim of our study was to describe the surface anatomy of the interlobar fissures using volumetric thin-section high-resolution computed tomography (HRCT). Retrospective assessment of HRCT examinations of 250 patients was performed. The localization of the oblique fissures was marked at three sites: posteriorly at its most superior medial limit, laterally in the midaxillary line, and inferiorly at the junction of the middle and lateral thirds of the hemithorax; posteriorly and laterally, this was to the nearest rib whilst inferiorly the position was described in relation to the diaphragm or chest wall. The localization of the horizontal fissure was marked anteriorly in relation to the nearest rib (or costal cartilage) and posteriorly where it intersected with the oblique fissure (superior, middle, or inferior third). Shapes of the fissures and differences between inspiration and expiration were also documented. Descriptive statistics were used to report the most frequent positions. The most frequent localization of the oblique fissure on the left side was posteriorly at the fourth rib (45%), laterally at the sixth rib (52%), and inferiorly in the anterior third of the hemidiaphragm (60%). The right oblique fissure was located posteriorly at the fifth rib (50%), laterally at the sixth rib (50%), and inferiorly in the anterior third of the hemidiaphragm (71%). The horizontal fissure most commonly originated in the middle third of the oblique fissure (61%) and met the anterior thoracic wall at the level of the fourth rib (51%). The most frequent shape of the left oblique fissure was linear (78%), whereas S-shaped and linear configurations (28% each) were most frequent on the right. No difference was found in the surface markings of the fissures between inspiration and expiration in 90% of cases. The considerable individual variation in the position and shape of the interlobar fissures helps to explain the variable descriptions of their surface anatomy in the

  12. Joints, fissures, and voids in rhyolite welded ash-flow tuff at Teton damsite, Idaho

    USGS Publications Warehouse

    Prostka, Harold J.

    1977-01-01

    Several kinds of joints, fissures, and voids are present in densely welded rhyolite ash-flow tuff at Teton damsite. Older fissures and voids probably were formed in the ash-flow sheet during secondary flowage, which probably was caused by differential compaction or settling over irregular topography. The younger, more abundant fissures are mostly steep cooling joints that probably have been opened farther by horizontal tectonic extension and gravitational creep, perhaps aided by lateral stress relief.

  13. Comparative study of vent and seep macrofaunal communities in the Guaymas Basin

    NASA Astrophysics Data System (ADS)

    Portail, M.; Olu, K.; Escobar-Briones, E.; Caprais, J. C.; Menot, L.; Waeles, M.; Cruaud, P.; Sarradin, P. M.; Godfroy, A.; Sarrazin, J.

    2015-06-01

    Understanding the ecological processes and connectivity of chemosynthetic deep-sea ecosystems requires comparative studies. In the Guaymas Basin (Gulf of California, Mexico), the presence of seeps and vents in the absence of biogeographic barrier, comparable sedimentary settings and depths offers a unique opportunity to assess the role of ecosystem specific environmental conditions on macrofaunal communities. Six seep and four vent assemblages were studied, three of which were characterised by common major foundation taxa: vesicomyid bivalves, siboglinid tubeworms and microbial mats. Macrofaunal community structure at the family level showed that density, diversity and composition patterns were primarily shaped by seep and vent common abiotic factors including methane and hydrogen sulphide concentrations. The type of substratum and the heterogeneity provided by foundation species were identified as additional structuring factors and their roles were found to vary according to fluid regimes. Surprisingly, the presence of vent environmental specificities, with higher temperature, higher metal concentrations and lower pH was not significant in explaining community patterns. Moreover, Guaymas seep and vent shared an important number of common species suggesting frequent connections between the two ecosystems. Finally, this study provides further support for the hypothesis of continuity among deep-sea seep and vent ecosystems.

  14. 14 CFR 29.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Fuel tank vents and carburetor vapor vents. 29.975 Section 29.975 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Fuel System §...

  15. 14 CFR 29.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Fuel tank vents and carburetor vapor vents. 29.975 Section 29.975 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Fuel System §...

  16. 14 CFR 25.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Fuel tank vents and carburetor vapor vents. 25.975 Section 25.975 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Fuel System §...

  17. 14 CFR 25.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Fuel tank vents and carburetor vapor vents. 25.975 Section 25.975 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Fuel System §...

  18. 14 CFR 29.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Fuel tank vents and carburetor vapor vents. 29.975 Section 29.975 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Fuel System §...

  19. 14 CFR 29.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Fuel tank vents and carburetor vapor vents. 29.975 Section 29.975 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Fuel System §...

  20. 14 CFR 25.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Fuel tank vents and carburetor vapor vents. 25.975 Section 25.975 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Fuel System §...

  1. 14 CFR 25.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Fuel tank vents and carburetor vapor vents. 25.975 Section 25.975 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Fuel System §...

  2. 14 CFR 23.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... will constitute a fire hazard or from which fumes may enter personnel compartments; and (7) Vents must... a separate vent line to lead vapors back to the top of one of the fuel tanks. If there is more than... line must lead back to the fuel tank to be used first, unless the relative capacities of the tanks...

  3. 14 CFR 25.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... may end at any point— (i) Where the discharge of fuel from the vent outlet would constitute a fire... carburetor with vapor elimination connections must have a vent line to lead vapors back to one of the fuel... return line must lead back to the fuel tank used for takeoff and landing....

  4. 14 CFR 29.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... end at any point— (i) Where the discharge of fuel from the vent outlet would constitute a fire hazard... with vapor elimination connections must have a vent line to lead vapors back to one of the fuel tanks... line must lead back to the fuel tank used for takeoff and landing....

  5. On homogenization of a variational inequality for an elastic body with periodically distributed fissures

    SciTech Connect

    Pastukhova, S E

    2000-02-28

    We study the problem of small deformations of an elastic body with periodically distributed fissures, where one-sided constraints are imposed on the sides of the fissures; this problem is equivalent to a variational inequality. We prove that if the linear size of the period of the distribution of the fissures tends to zero, then the solutions of this problem converge in the L{sup 2}-norm to the solution of the homogenized problem, which is a non-linear boundary-value problem of elasticity theory for a domain without fissures.

  6. ANALYSIS OF VENTING OF A RESIN SLURRY

    SciTech Connect

    Laurinat, J.; Hensel, S.

    2012-03-27

    A resin slurry venting analysis was conducted to address safety issues associated with overpressurization of ion exchange columns used in the Purex process at the Savannah River Site (SRS). If flow to these columns were inadvertently interrupted, an exothermic runaway reaction could occur between the ion exchange resin and the nitric acid used in the feed stream. The nitric acid-resin reaction generates significant quantities of noncondensable gases, which would pressurize the column. To prevent the column from rupturing during such events, rupture disks are installed on the column vent lines. The venting analysis models accelerating rate calorimeter (ARC) tests and data from tests that were performed in a vented test vessel with a rupture disk. The tests showed that the pressure inside the test vessel continued to increase after the rupture disk opened, though at a slower rate than prior to the rupture. Calculated maximum discharge rates for the resin venting tests exceeded the measured rates of gas generation, so the vent size was sufficient to relieve the pressure in the test vessel if the vent flow rate was constant. The increase in the vessel pressure is modeled as a transient phenomenon associated with expansion of the resin slurry/gas mixture upon rupture of the disk. It is postulated that the maximum pressure at the end of this expansion is limited by energy minimization to approximately 1.5 times the rupture disk burst pressure. The magnitude of this pressure increase is consistent with the measured pressure transients. The results of this analysis demonstrate the need to allow for a margin between the design pressure and the rupture disk burst pressure in similar applications.

  7. Examination of frit vent from Sixty-Watt Heat Source simulant fueled clad vent set

    SciTech Connect

    Ulrich, G.B.

    1995-11-01

    The flow rate and the metallurgical condition of a frit vent from a simulant-fueled clad vent set (CVS) that had been hot isostatically pressed (HIP) for the Sixty-Watt Heat Source program were evaluated. The flow rate form the defueled vent cup subassembly was reduced approximately 25% from the original flow rate. No obstructions were found to account for the reduced flow rate. Measurements indicate that the frit vent powder thickness was reduced about 30%. Most likely, the powder was compressed during the HIP operation, which increased the density of the powder layer and thus reduced the flow rate of the assembly. All other observed manufacturing attributes appeared to be normal, but the vent hole activation technique needs further refinement before it is used in applications requiring maximum CVS integrity.

  8. Fluoride release and uptake abilities of different fissure sealants

    PubMed Central

    Andenna, Gianluigi; Ceci, Matteo; Beltrami, Riccardo; Colombo, Marco; Cucca, Lucia

    2016-01-01

    Background The long-term capability of resin sealants and glass ionomer cements to release fluoride is associated to a reduction in pit and fissure caries. The regular use of fluoride varnishes/toothpastes can result in the absorption of fluoride into the sealant. The objective of the present study was to assess the fluoride release/uptake capacities of different fissure sealants. Material and Methods Three different fissure sealants (Fuji Triage/GC, Fissurit FX/Voco and Grandio Seal/Voco) were examined. Ten discs of each material were prepared. Each disc was incubated with distilled water and then the solution analyzed for diluted for fluoride concentration, using a combination of fluoride electrode (OrionGP 1 S/N 13824, Orion Research Inc, Boston, MA, USA) connected to an expandable ion analyzer (Orion 720A, Orion Research Inc, Boston, MA, USA). Standard curves between 1 and 100 ppm F- were used to calibrate the electrode. Cumulative fluoride release was measured on days 1, 2, 3, 5, 7, 21, 35 and 49, then two different fluoride varnishes/pastes (Profluorid Varnish/Voco, MI Paste Plus/GC), were applied to the sealants tested, and fluoride release (after reuptake) was measured on days 56, 70 and 84. Results Kruskal Wallis test confirmed significant differences in fluoride release between Fuji Triage/GC and Fissurit FX/Voco and Grandio Seal/Voco from day 1 (P < 0.001). The application of fluoride varnish Profluorid Varnish enhanced the fluoride release for all sealants (P < 0.05). MI Paste Plus enhanced the fluoride release for all sealants except for Fuji Triage/GC (P > 0.05). Conclusions The GIC-based sealant (Fuji Triage/GC) released significantly more fluoride than the resin sealants tested. The exposure to the fluoridated varnish (Profluorid Varnish) significantly recharged the sealants tested more than the CPP-ACPF toothpaste (MI Paste Plus). Key words:Fissure sealants, fluoride release, fluoride uptake, glass ionomer cements. PMID:27398179

  9. Bonding Agents in Pit and Fissure Sealants: A Review

    PubMed Central

    Das, Usha Mohan; G, Suma

    2009-01-01

    Dental adhesive systems used for bonding dental resins to enamel and dentin have evolved through several "generations," with changes in chemistry, mechanism, number of bottles, application technique, and clinical effectiveness. The trend in the latest generation of dental bonding systems is to reduce the number of components and clinical placement steps. The introduction of i bond, a single-bottle dental adhesive system, is the latest of the new generation materials, and combines etchant, adhesive, and desensitizer in one component. This paper describes different dentin bonding agents, its evolution, mechanism of action and different commercially available dentin bonding agents and their role in the retention of pit and fissure sealant. PMID:25206115

  10. A rare case of myeloid sarcoma presenting as anal fissure

    PubMed Central

    VECCHIO, R.; INTAGLIATA, E.; FIUMARA, P.F.; VILLARI, L.; MARCHESE, S.; CACCIOLA, E.

    2015-01-01

    Myeloid sarcoma is a tumor composed of myeloblasts occurring at an extramedullary site. It may develop in patients with acute myeloid leukemia, myeloproliferative or myelodysplastic syndrome, sometimes preceding onset of the systemic disease. Frequent sites of myeloid sarcoma are bones or various soft tissues. Gastrointestinal involvement is very rare. We report a unique case of myeloid sarcoma presenting as a painful anal fissure, in a patient with a history of acute myeloid leukemia. The diagnosis was achieved by a surgical excisional biopsy and immunoistochemical staining. PMID:26712260

  11. Sylvian fissure epidermoid cyst presenting with intention tremor

    PubMed Central

    Shah, Abhidha; Makkiyah, Feda; Goel, Atul

    2016-01-01

    Epidermoid tumors are benign tumors which contain keratin, cellular debris, and cholesterol, and are lined with stratified squamous epithelium. They grow in discreet silence sustained over a multitude of years. The tumors most commonly present with headache and seizures. We report the case of a 24-year-old male with a large sylvian fissure epidermoid tumor who presented with intention tremor. The patient was operated, and a near-total excision of the tumor was performed with a resolution of the tremor. PMID:27057232

  12. Effects of Vent Asymmetry on Explosive Eruptions

    NASA Astrophysics Data System (ADS)

    Sim, S.; Ogden, D. E.

    2012-12-01

    Current computer models of volcanic eruptions are typically based on symmetric vent and conduit geometries. However, in natural settings, these features are rarely perfectly symmetric. For example, the May 18, 1980 eruption of Mount St Helens (MSH) took place through a highly asymmetrical crater due to the preceding landslide and subsequent vent erosion. In supersonic, high pressure eruptions, such as what may have occurred at MSH, vent and crater asymmetry can strongly affect the directionality of the gas-thrust region. These effects on eruption direction may have implications for the formation of lateral blasts and pyroclastic density currents (PDCs). Here, we present preliminary results from numerical simulations using CartaBlanca, a Java based simulation tool for non-linear physics as developed at Los Alamos National Laboratory. Using 2D time-dependent simulations of explosive volcanic eruptions, we study the effects of vent asymmetry on a variety of eruptive conditions. Preliminary results suggest that asymmetric vent shape may provide an additional mechanism for the formation of lateral blasts and PDCs.

  13. Effect of topical glyceryl trinitrate on anodermal blood flow in patients with chronic anal fissures.

    PubMed

    Kua, K B; Kocher, H M; Kelkar, A; Patel, A G

    2001-09-01

    Recent studies have highlighted the role of increased internal anal sphincter pressure and decreased anodermal blood flow in the pathogenesis of chronic anal fissures. The duration of the effect of topical 0.2% glyceryl trinitrate (GTN) ointment on anodermal blood flow in fissure and normal areas was investigated in patients with chronic anal fissures. Six patients with chronic anal fissures in the posterior midline participated in the study. Blood flow measurements were performed on the anoderm using laser Doppler flowmetry before and immediately after the topical application of 0.2% GTN ointment and subsequent readings were taken at 5, 15, 30, 45 and 60 min in all four quadrants. The mean anodermal blood flow in the fissure region is significantly lower than the mean blood flow of the rest of the anoderm before 0.2% GTN ointment is applied (228.7 +/- 61.8 flux units vs 439.3 +/- 25.5 flux units, respectively; P < 0.05). Immediately after the application of local 0.2% GTN ointment there is a significant increase in anodermal blood flow over the anal fissure region (457.8 +/- 56.5 flux units; P < 0.05) compared to the rest of the anoderm (457.4 +/- 30.8 flux units). This increase is most marked at 5 min post-GTN ointment application in the fissure area (474.6 +/- 41.1 flux units) and the blood flow in the fissure region is consistently above the rest of the anoderm for most of the 60 min. There is clearly reduced blood flow to the chronic anal fissure region compared to the rest of the anoderm. Topical application of glyceryl trinitrate ointment seems to significantly improve the blood flow to the fissured area in the first hour. This may therefore help in the healing of chronic anal fissures.

  14. Hydrothermal vent yields multitude of manganese

    NASA Astrophysics Data System (ADS)

    A rising plume of water from an active submarine hydrothermal spring discovered 500 km west of Newport, Ore., contains the highest concentrations of manganese yet reported, according to researchers at the U.S. Geological Survey in Menlo Park and at the University of Washington in Seattle. The vent, one of many submarine springs that have deposited large deposits of zinc- and silver-rich metals along the Juan de Fuca Ridge, may be a source of renewable minerals.‘The discovery of the active water discharge from the vent sites is particularly significant because it indicates that the polymetallic deposits are still being deposited and may represent a renewable mineral deposit,’ according to William R. Normark, a marine geologist with the USGS and chief scientist aboard the S. P. Lee, the USGS research ship that was used to collect water samples above the hydrothermal vent.

  15. Medium Fidelity Simulation of Oxygen Tank Venting

    NASA Technical Reports Server (NTRS)

    Sweet, Adam; Kurien, James; Lau, Sonie (Technical Monitor)

    2001-01-01

    The item to he cleared is a medium-fidelity software simulation model of a vented cryogenic tank. Such tanks are commonly used to transport cryogenic liquids such as liquid oxygen via truck, and have appeared on liquid-fueled rockets for decades. This simulation model works with the HCC simulation system that was developed by Xerox PARC and NASA Ames Research Center. HCC has been previously cleared for distribution. When used with the HCC software, the model generates simulated readings for the tank pressure and temperature as the simulated cryogenic liquid boils off and is vented. Failures (such as a broken vent valve) can be injected into the simulation to produce readings corresponding to the failure. Release of this simulation will allow researchers to test their software diagnosis systems by attempting to diagnose the simulated failure from the simulated readings. This model does not contain any encryption software nor can it perform any control tasks that might be export controlled.

  16. Investigations Into Tank Venting for Propellant Resupply

    NASA Technical Reports Server (NTRS)

    Hearn, H. C.; Harrison, Robert A. (Technical Monitor)

    2002-01-01

    Models and simulations have been developed and applied to the evaluation of propellant tank ullage venting, which is integral to one approach for propellant resupply. The analytical effort was instrumental in identifying issues associated with resupply objectives, and it was used to help develop an operational procedure to accomplish the desired propellant transfer for a particular storable bipropellant system. Work on the project was not completed, and several topics have been identified as requiring further study; these include the potential for liquid entrainment during the low-g and thermal/freezing effects in the vent line and orifice. Verification of the feasibility of this propellant venting and resupply approach still requires additional analyses as well as testing to investigate the fluid and thermodynamic phenomena involved.

  17. Fissure sealants: Knowledge and practice of Yemeni dental practitioners

    PubMed Central

    Al-Maweri, Sadeq Ali; Al-Jamaei, Aisha Ahmed; Halboub, Esam Saleh; Al-Soneidar, Walid Ahmed; Tarakji, Bassel; Alsalhani, Anas

    2016-01-01

    Objectives This study was conducted to evaluate Yemeni dental practitioners' knowledge and practices concerning fissure sealants. Materials and Methods: A modified questionnaire consisted of 25-items was distributed to 500 dentists working in Sana'a City. Descriptive statistics and Chi-square/Fisher's exact tests were used for statistical analyses. Results: The response rate was 74%. Most of the respondents were male (61.3%), general practitioners (84.2%), and had <5 years of clinical experience (48.3%). The respondents showed a reasonable level of knowledge about sealants, with the majority (88%) believed that there is strong scientific evidence about fissure sealants effectiveness and around 90% showed a good understanding of sealant placement instructions. On the other hand, respondents showed insufficient knowledge about sealants clinical practice. Conclusion: Although a high proportion of dental practitioners showed adequate knowledge about dental sealant, following guidelines and standardized procedures in clinical practice is lacking. These emphasize the need for regular continuing education courses for dental professional. PMID:27095903

  18. Combined approach in the treatment of chronic anal fissures.

    PubMed

    Vershenya, S; Klotz, J; Joos, A; Bussen, D; Herold, A

    2015-03-01

    This study was designed to evaluate the healing and complications rates in surgically and conservatively treated patients with chronic anal fissure. Conservative treatment consisted of nitrate or diltiazem ointment. In case of surgery, fissurectomy was performed. In total, 340 patients were included in the study. Among them, 162 patients had surgery and 178 patients had conservative treatment. The healing rate at surgically treated group of patients varied between 95 and 98% depending on previous treatment. Group treated with nitrate ointment and group treated with diltiazem ointment showed, respectively 62% and 52% healing rates. Difference between ointments was not statistically significant. Average healing time was between 105 and 123 days and complication rates were between 1.7 and 5.4%. The surgical treatment showed much higher healing rates and thus should recommended as primary treatment option for the chronic anal fissure, especially if there are chronic secondary lesions already present. In case of conservative treatment, either nitrate or diltiazem ointment could be used with similar efficacy.

  19. Nonsurgical approaches for the treatment of anal fissures.

    PubMed

    Dhawan, Sanju; Chopra, Sunny

    2007-06-01

    Chronic anal fissure (CAF) is usually associated with internal anal sphincter spasm, the relief of which is central to provide fissure healing. The treatment for CAF has undergone a transformation in recent years from surgical to medical. Both the approaches share the common goal of reducing the spasm. Though surgical treatment has a high success rate, it can permanently impair fecal continence in a large number of patients. Smooth muscle relaxation seems to be a novel way by which more than 60% of the patients can be cured with the topical use of the agents. This treatment is in addition to the normalization of stools mostly. Smooth muscle relaxation is well tolerated, can be administered on an outpatient basis, does not cause any lesion of the continence organ, and subsequently, does not lead to any permanent latent or apparent fecal incontinence. This review encompasses various agents that are used for smooth muscle relaxation. In addition, it describes various clinical studies reported in the literature with their success rates and side effects.

  20. Turbulent atmospheric plumes above line sources with an application to volcanic fissure eruptions on the terrestrial planets

    NASA Technical Reports Server (NTRS)

    Stothers, Richard B.

    1989-01-01

    The theory of turbulent plumes maintained above steady line sources of buoyancy is worked out in detail within the limitations of Taylor's entrainment assumption. It is applied to the structure of a pure plume injected into a stably stratified atmosphere. Volcanic basalt eruptions that develop from long, narrow vents create line source plumes, which rise well above the magmatic fire fountains playing near the ground level. The eruption of Laki in 1783 may provide an example of this style of eruption. Flood basalts are more ancient examples. Evidence of enormous fissure eruptions that occurred in the past on Mars and Venus also exists. Owing to the different properties of the atmospheres on these two planets from those on the earth, heights of line source plumes are expected to vary in the ratios 1:6:0.6 (earth:Mars:Venus). It is very unlikely that the observed increase of sulfur dioxide above the Venusian cloud deck in 1978 could have been due to a line source volcanic eruption, even if it had been a flood basalt eruption.

  1. Energy metabolism and cellular homeostasis trade-offs provide the basis for a new type of sensitivity to ocean acidification in a marine polychaete at a high-CO2 vent: adenylate and phosphagen energy pools versus carbonic anhydrase.

    PubMed

    Turner, Lucy M; Ricevuto, Elena; Massa-Gallucci, Alexia; Gambi, Maria-Cristina; Calosi, Piero

    2015-07-01

    Species distributions and ecology can often be explained by their physiological sensitivity to environmental conditions. Whilst we have a relatively good understanding of how these are shaped by temperature, for other emerging drivers, such as PCO2  we know relatively little. The marine polychaete Sabella spallanzanii increases its metabolic rate when exposed to high PCO2  conditions and remains absent from the CO2 vent of Ischia. To understand new possible pathways of sensitivity to CO2 in marine ectotherms, we examined the metabolic plasticity of S. spallanzanii exposed in situ to elevated PCO2  by measuring fundamental metabolite and carbonic anhydrase concentrations. We show that whilst this species can survive elevated PCO2  conditions in the short term, and exhibits an increase in energy metabolism, this is accompanied by a significant decrease in carbonic anhydrase concentration. These homeostatic changes are unlikely to be sustainable in the longer term, indicating S. spallanzanii may struggle with future high PCO2  conditions. © 2015. Published by The Company of Biologists Ltd.

  2. Hydrothermal vents and the origin of life.

    PubMed

    Martin, William; Baross, John; Kelley, Deborah; Russell, Michael J

    2008-11-01

    Submarine hydrothermal vents are geochemically reactive habitats that harbour rich microbial communities. There are striking parallels between the chemistry of the H(2)-CO(2) redox couple that is present in hydrothermal systems and the core energy metabolic reactions of some modern prokaryotic autotrophs. The biochemistry of these autotrophs might, in turn, harbour clues about the kinds of reactions that initiated the chemistry of life. Hydrothermal vents thus unite microbiology and geology to breathe new life into research into one of biology's most important questions - what is the origin of life?

  3. Vented Cavity Radiant Barrier Assembly And Method

    DOEpatents

    Dinwoodie, Thomas L.; Jackaway, Adam D.

    2000-05-16

    A vented cavity radiant barrier assembly (2) includes a barrier (12), typically a PV module, having inner and outer surfaces (18, 22). A support assembly (14) is secured to the barrier and extends inwardly from the inner surface of the barrier to a building surface (14) creating a vented cavity (24) between the building surface and the barrier inner surface. A low emissivity element (20) is mounted at or between the building surface and the barrier inner surface. At least part of the cavity exit (30) is higher than the cavity entrance (28) to promote cooling air flow through the cavity.

  4. Comparison of a New Thiomicrospira Strain from the Mid-Atlantic Ridge with Known Hydrothermal Vent Isolates†

    PubMed Central

    Wirsen, C. O.; Brinkhoff, T.; Kuever, J.; Muyzer, G.; Molyneaux, S.; Jannasch, H. W.

    1998-01-01

    A new autotrophic Thiomicrospira strain, MA-3, was isolated from the surface of a polymetal sulfide deposit collected at a Mid-Atlantic Ridge hydrothermal vent site. The DNA homology among three vent isolates, Thiomicrospira crunogena, Thiomicrospira sp. strain L-12, and Thiomicrospira sp. strain MA-3, was 99.3% or higher, grouping them as the same species, T. crunogena (type strain, ATCC 35932). The fact that T. crunogena and Thiomicrospira sp. strain L-12 were isolated from Pacific vent sites demonstrates a cosmopolitan distribution of this species. PMID:9758841

  5. Preserving rice quality: fine mapping and introgressing a fissure resistance locus

    USDA-ARS?s Scientific Manuscript database

    Rice (Oryza sativa L.) kernel fissuring is a major concern of both rice producers and millers. Fissures are small cracks in the rice kernels that increase the percentage of breakage among the kernels when they are transported and milled, which decreases the value of processed rice. This study employ...

  6. Response to early generation selection for resistance to rice kernel fissuring

    USDA-ARS?s Scientific Manuscript database

    The value of milled rice (Oryza sativa L.) depends on the percent whole versus broken kernels after milling. Kernel fissures caused by pre- or post-harvest stresses are the leading cause of breakage upon milling. ‘Cypress’ is known to be more fissure resistant (FR) than most cultivars, but breeding ...

  7. Early screening of recombinant inbred lines for fissure resistance in non-semidwarf rice

    USDA-ARS?s Scientific Manuscript database

    Rice (Oryza sativa L.) kernel fissuring poses a major problem for both rice farmers and millers. It results in the decreased value of milled rice because of the increase in the percentage of broken kernels associated with fissuring. This study employs the use of fine mapping to increase the genetic ...

  8. Pulmonary fissure development is a prognostic factor for patients with resected stage I lung adenocarcinoma.

    PubMed

    Lee, Seokkee; Lee, Jin Gu; Lee, Chang Young; Kim, Dae Joon; Chung, Kyung Young

    2016-12-01

    Pulmonary fissure differs among patients, but the relationship between pulmonary fissure development and survival in patients with resected lung adenocarcinoma has not been evaluated. In this study, we analyzed the effect of fissure development on prognosis in patients with stage I lung adenocarcinoma. From January 2009 to December 2012, data, including pulmonary fissure development, were collected prospectively for all lung cancer, and this was a retrospective study of prospectively collected data. In total, 297 patients who had undergone a lobectomy and had pathologic stage I adenocarcinoma were analyzed. Patients were categorized into two groups based on fissure sum average (FSA) fissure development scores. Group A patients ranged from complete to 30% incomplete (0 ≤ FSA ≤ 1) while in Group B patients development was more than 30% incomplete (1 < FSA ≤ 3). In univariate analysis, Group B had poorer overall 5 year survival than did Group A (83.1% vs. 96.5%, P = 0.015). Multivariate analysis revealed that the level of fissure development was a significant prognostic factor for overall survival (HR = 3.905, CI = 1.168-13.057, P = 0.027). The overall survival of patients with resected stage I adenocarcinoma was adversely affected by incomplete fissure development. J. Surg. Oncol. 2016;114:848-852. © 2016 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  9. The Averno 2 fissure eruption: a recent small-size explosive event at the Campi Flegrei Caldera (Italy)

    NASA Astrophysics Data System (ADS)

    di Vito, Mauro Antonio; Arienzo, Ilenia; Braia, Giuseppe; Civetta, Lucia; D'Antonio, Massimo; di Renzo, Valeria; Orsi, Giovanni

    2011-04-01

    The Averno 2 eruption (3,700 ± 50 a B.P.) was an explosive low-magnitude event characterized by magmatic and phreatomagmatic explosions, generating mainly fall and surge beds, respectively. It occurred in the Western sector of the Campi Flegrei caldera (Campanian Region, South Italy) at the intersection of two active fault systems, oriented NE and NW. The morphologically complex crater area, largely filled by the Averno lake, resulted from vent activation and migration along the NE-trending fault system. The eruption generated a complex sequence of pyroclastic deposits, including pumice fall deposits in the lower portion, and prevailing surge beds in the intermediate-upper portion. The pyroclastic sequence has been studied through stratigraphical, morphostructural and petrological investigations, and subdivided into three members named A through C. Member A was emplaced during the first phase of the eruption mainly by magmatic explosions which generated columns reaching a maximum height of 10 km. During this phase the eruption reached its climax with a mass discharge rate of 3.2 106 kg/s. Intense fracturing and fault activation favored entry of a significant amount of water into the system, which produced explosions driven by variably efficient water-magma interaction. These explosions generated wet to dry surge deposits that emplaced Member B and C, respectively. Isopachs and isopleths maps, as well as areal distribution of ballistic fragments and facies variation of surge deposits allow definition of four vents that opened along a NE oriented, 2 km long fissure. The total volume of magma extruded during the eruption has been estimated at about 0.07 km3 (DRE). The erupted products range in composition from initial, weakly peralkaline alkali-trachyte, to last-emplaced alkali-trachyte. Isotopic data and modeling suggest that mixing occurred during the Averno 2 eruption between a more evolved, less radiogenic stored magma, and a less evolved, more radiogenic magma

  10. Quantifying diffuse and discrete venting at the Tour Eiffel vent site, Lucky Strike hydrothermal field

    NASA Astrophysics Data System (ADS)

    Mittelstaedt, Eric; EscartíN, Javier; Gracias, Nuno; Olive, Jean-Arthur; Barreyre, Thibaut; Davaille, Anne; Cannat, Mathilde; Garcia, Rafael

    2012-04-01

    The relative heat carried by diffuse versus discrete venting of hydrothermal fluids at mid-ocean ridges is poorly constrained and likely varies among vent sites. Estimates of the proportion of heat carried by diffuse flow range from 0% to 100% of the total axial heat flux. Here, we present an approach that integrates imagery, video, and temperature measurements to accurately estimate this partitioning at a single vent site, Tour Eiffel in the Lucky Strike hydrothermal field along the Mid-Atlantic Ridge. Fluid temperatures, photographic mosaics of the vent site, and video sequences of fluid flow were acquired during the Bathyluck'09 cruise (Fall, 2009) and the Momarsat'10 cruise (Summer, 2010) to the Lucky Strike hydrothermal field by the ROV Victor6000 aboard the French research vessel the "Pourquoi Pas"? (IFREMER, France). We use two optical methods to calculate the velocities of imaged hydrothermal fluids: (1) for diffuse venting, Diffuse Flow Velocimetry tracks the displacement of refractive index anomalies through time, and (2) for discrete jets, Particle Image Velocimetry tracks eddies by cross-correlation of pixel intensities between subsequent images. To circumvent video blurring associated with rapid velocities at vent orifices, exit velocities at discrete vents are calculated from the best fit of the observed velocity field to a model of a steady state turbulent plume where we vary the model vent radius and fluid exit velocity. Our results yield vertical velocities of diffuse effluent between 0.9 cm s-1 and 11.1 cm s-1 for fluid temperatures between 3°C and 33.5°C above that of ambient seawater, and exit velocities of discrete jets between 22 cm s-1 and 119 cm s-1 for fluid temperatures between 200°C and 301°C above ambient seawater. Using the calculated fluid velocities, temperature measurements, and photo mosaics of the actively venting areas, we calculate a heat flux due to diffuse venting from thin fractures of 3.15 ± 2.22 MW, discrete venting of

  11. Spatial Compilation of Holocene Volcanic Vents in the Western Conterminous United States

    NASA Astrophysics Data System (ADS)

    Ramsey, D. W.; Siebert, L.

    2015-12-01

    A spatial compilation of all known Holocene volcanic vents in the western conterminous United States has been assembled. This compilation records volcanic vent location (latitude/longitude coordinates), vent type (cinder cone, dome, etc.), geologic map unit description, rock type, age, numeric age and reference (if dated), geographic feature name, mapping source, and, where available, spatial database source. Primary data sources include: USGS geologic maps, USGS Data Series, the Smithsonian Global Volcanism Program (GVP) catalog, and published journal articles. A total of 726 volcanic vents have been identified from 45 volcanoes or volcanic fields spanning ten states. These vents are found along the length of the Cascade arc in the Pacific Northwest, widely around the Basin and Range province, and at the southern margin of the Colorado Plateau into New Mexico. The U.S. Geological Survey (USGS) National Volcano Early Warning System (NVEWS) identifies 28 volcanoes and volcanic centers in the western conterminous U.S. that pose moderate, high, or very high threats to surrounding communities based on their recent eruptive histories and their proximity to vulnerable people, property, and infrastructure. This compilation enhances the understanding of volcano hazards that could threaten people and property by providing the context of where Holocene eruptions have occurred and where future eruptions may occur. Locations in this compilation can be spatially compared to located earthquakes, used as generation points for numerical hazard models or hazard zonation buffering, and analyzed for recent trends in regional volcanism and localized eruptive activity.

  12. Evaluation of Different Fissure Sealant Materials and Flowable Composites Used as Pit-and-fissure Sealants: A 24-Month Clinical Trial.

    PubMed

    Kucukyilmaz, Ebru; Savas, Selcuk

    2015-01-01

    The effectiveness of resin-based pit-and-fissure sealants mainly depends on their retention and integrity over time. The purpose of this study was to evaluate retention rates of two different pit-and-fissure sealants compared with a flowable composite and a self-adhesive flowable composite over a 24 month period. A split-mouth study design was used for all four permanent first molars of each patient. They were subjected to different kinds of sealants--either flowable composites or with fissure sealants. The flowable composites used were: flowable composite with an adhesive system (Tetric EvoFlow); and a self-adhesive flowable composite (Vertise Flow). The fissure sealants used were: a highly filled pit-and-fissure sealant (Fissurit FX); and a highly filled nano-hybrid pit-and-fissure sealant (Grandio Seal). Evaluation of the sealants was carried out at three-, six-, 12-, 18-, and 24-month follow-up visits. The complete retention rates were 95.7 percent for Tetric EvoFlow, 80.6 percent for Fissurit FX, 73.1 percent for Grandio Seal, and 62.9 percent for Vertise Flow. The retention rate of Tetric EvoFlow was significantly higher among all materials tested (P<0.05). The flowable composite used with an adhesive system was found to be superior to other sealing materials.

  13. Comparison of different methods of cleaning and preparing occlusal fissure surface before placement of pit and fissure sealants: An in vivo study.

    PubMed

    Hegde, Rahul J; Coutinho, Rochelle C

    2016-01-01

    To evaluate an individual method of cleaning and preparing occlusal fissure surface before placement of pit and fissure sealant and to determine a method for better retention of the sealant. The present study consisted of 100 young permanent molar teeth divided into four equal groups: Group 1-Brushing only, Group 2-Application of pumice slurry, Group 3-Surface conditioning, and Group 4-Control (without any preparation). Subsequent to fissure preparation, the fissures were etched using 37% phosphoric acid except for Group 3, which was etched using 10% maleic acid for 30 s. The samples were then rinsed for 10 s using air water spray of the three-way syringe and dried using oil-free compressed air with a hand pump air pressure syringe. After ensuring a frosted appearance of the enamel at the fissure entrance, pit and fissure sealants were applied on the surface according to manufacturer's instructions. All the cases were clinically evaluated for retention after 3 months, 6 months, and 12 months of application and the retention rate was assessed based on the criteria proposed by Simonsen. The pumice slurry group and surface conditioning group showed results with 100%, 96%, and 92% complete retention seen at 3 months, 6 months, and 12 months, respectively. The pumice slurry group and surface conditioning group showed a significantly higher retention when compared to the brushing group, whereas the control group (without any preparation) showed the least retention when compared to all the other groups.

  14. 40 CFR 63.690 - Standards: Process vents.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... process vent through a closed-vent system to a control device that meets the standards specified in § 63... a control device; however, a second condenser or other organic recovery device that is...

  15. 46 CFR 38.20-1 - Venting-T/ALL.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... relief valve and the vent outlets. (h) Provisions shall be made to drain condensate from the vent header piping. Special precautions shall insure that condensate does not accumulate at or near the relief...

  16. 46 CFR 38.20-1 - Venting-T/ALL.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... relief valve and the vent outlets. (h) Provisions shall be made to drain condensate from the vent header piping. Special precautions shall insure that condensate does not accumulate at or near the relief...

  17. 46 CFR 38.20-1 - Venting-T/ALL.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... relief valve and the vent outlets. (h) Provisions shall be made to drain condensate from the vent header piping. Special precautions shall insure that condensate does not accumulate at or near the relief...

  18. Risk factors special to eastern culture for the development of anal fissure.

    PubMed

    Erel, Serap; Adahan, Didem; Kismet, Kemal; Caylan, Ayse; Tanrikulu, Yusuf; Akkus, Mehmet Ali

    2009-01-01

    To reveal the effect of diet, bowel functions and toilet habits on the development of anal fissure. One hundred patients complaining of anal fissure were included to the case group; and one hundred age- and gender-matched patients referred for other reasons except for anorectal complaints were included to the control group. The information was obtained by face to face interviews using questionnaires. Statistically significant differences were found in coffee, fruit, and meat consumption between the groups. The patients suffering from anal fissure avoided paprika consumption. The rate of anal fissure incidence was higher in squat toilet users. This study is the first study which evaluates the risk factors such as paprika consumption and squat toilet usage that are specific to Eastern culture. Further studies including large numbers of population are needed to evaluate different risk factors for anal fissure development (Tab. 2, Ref. 11). Full Text (Free, PDF) www.bmj.sk.

  19. Surface fissures in articular cartilage: effect of pathological changes in synovial fluid.

    PubMed

    Kafka, Vratislav

    2002-01-01

    A unified mathematical model of two different modes of inception of fissures at the surface of articular cartilage in healthy and pathological joints. The superficial tangential zone of articular cartilage is modeled as a three-phase medium consisting of collagen fibers, matrix, and of infiltrated thin constituent of synovial fluid. The author's general mesomechanical concept is applied to the analysis of deterioration of articular cartilage. Theoretical analysis based on the results of the author's preceding paper. The presented analysis shows that superficial fissures in articular cartilage can also be caused by pathological thinning of synovial fluid. Whereas in healthy joints the probable cause of creation of fissures at the surface of cartilage was shown to be fast impact loading, in joints with inflammatory synovial fluid the fissures can be caused by plain walking. Appearance of surface fissures in articular cartilage is a serious, still not fully clarified problem that deserves attention.

  20. Injections of botulinum A toxin for the treatment of anal fissures.

    PubMed

    Trzciński, Radzisław; Dziki, Adam; Tchórzewski, Marcin

    2002-01-01

    To find out how injections of botulinum A toxin influence the healing of anal fissures. Retrospective study. Medical University of Lodz, Poland. 13 patients (6 women, 7 men), mean age 49 (range 31-78), treated with injections of botulinum A toxin 50 units on either side of the anal fissure into the internal anal sphincter from May to December 1999. Complications and relapse. Seven fissures had healed by one month and four by two months. Two remained unhealed but asymptomatic. There was no incontinence of flatus or faeces after three months of treatment. Resting anal pressure was significantly lower in 10 of 13 patients compared with before treatment (p < 0.05). One fissure relapsed after 4 months and this patient had a successful anal stretch. Injection of botulinum A toxin gives good results in the treatment of anal fissures.

  1. Geological and geochemical controls on the distribution of Alviniconcha vent snail symbioses: Have we finally linked mantle to microbe? (Invited)

    NASA Astrophysics Data System (ADS)

    Girguis, P. R.; Beinart, R.; Sanders, J.; Seewald, J.

    2010-12-01

    Gastropods of the genus Alviniconcha are found at hydrothermal vent fields in the Western Pacific, and have been reported to associate with either γ- or ɛ-Proteobacterial endosymbionts. These symbionts harness energy from the oxidation of chemicals in vent fluid to fix inorganic carbon and are the primary source of nutrition for the holobiont. An extensive sampling effort during a recent expedition to the Eastern Lau Spreading Center (ELSC) has revealed that Alviniconcha host both previously observed symbiont types, as well as an additional γ- proteobacterial symbiont. Specifically, we collected 266 Alviniconcha individuals from four vent fields along the spreading center (30-140km apart) which span the north-south transition from fast spreading, basalt-hosted to slower spreading, andesite-hosted fields. Vent fluids from each field were also analyzed for the abundances of aqueous volatile and non-volatile species. The symbionts of all collected Alviniconcha were genotyped using restriction fragment length polymorphism analysis as well as quantitative PCR. Individuals were found to primarily host one of the three symbiont genotypes (two γ- and one ɛ-Proteobacteria). Notably, we found that the two northern-most sites (basalt-hosted vents) were greatly dominated by individuals with the ɛ-Proteobacterial symbiont, while the two southern sites (andesite-hosted vents) were dominated by individuals hosting one of the two γ-Proteobacterial symbionts. This pattern corresponds to differences in the aqueous chemistry of the vent fluids along the spreading center. In particular, we have measured higher concentrations of hydrogen and hydrogen sulfide in the vent fluids at the northern sites than in the fluids of the southern sites. We posit that vent chemistry -which is influenced by subsurface water-rock interactions- may be influencing the dominance of each symbiont type along the ELSC. The putative implications for the role that geology and geochemistry plays in

  2. Dual symbiosis of the vent shrimp Rimicaris exoculata with filamentous gamma- and epsilonproteobacteria at four Mid-Atlantic Ridge hydrothermal vent fields.

    PubMed

    Petersen, Jillian M; Ramette, Alban; Lott, Christian; Cambon-Bonavita, Marie-Anne; Zbinden, Magali; Dubilier, Nicole

    2010-08-01

    The shrimp Rimicaris exoculata from hydrothermal vents on the Mid-Atlantic Ridge (MAR) harbours bacterial epibionts on specialized appendages and the inner surfaces of its gill chamber. Using comparative 16S rRNA sequence analysis and fluorescence in situ hybridization (FISH), we examined the R. exoculata epibiosis from four vents sites along the known distribution range of the shrimp on the MAR. Our results show that R. exoculata lives in symbiosis with two types of filamentous epibionts. One belongs to the Epsilonproteobacteria, and was previously identified as the dominant symbiont of R. exoculata. The second is a novel gammaproteobacterial symbiont that belongs to a clade consisting exclusively of sequences from epibiotic bacteria of hydrothermal vent animals, with the filamentous sulfur oxidizer Leucothrix mucor as the closest free-living relative. Both the epsilon- and the gammaproteobacterial symbionts dominated the R. exoculata epibiosis at all four MAR vent sites despite striking differences between vent fluid chemistry and distances between sites of up to 8500 km, indicating that the symbiosis is highly stable and specific. Phylogenetic analyses of two mitochondrial host genes showed little to no differences between hosts from the four vent sites. In contrast, there was significant spatial structuring of both the gamma- and the epsilonproteobacterial symbiont populations based on their 16S rRNA gene sequences that was correlated with geographic distance along the MAR. We hypothesize that biogeography and host-symbiont selectivity play a role in structuring the epibiosis of R. exoculata. © 2009 Society for Applied Microbiology and Blackwell Publishing Ltd.

  3. Hydro-Thermal Vent Mapping with Multiple AUV’s

    DTIC Science & Technology

    2016-06-07

    MARIUS and a surface catamaran ( AZIMOV) will perform broad are survey to identify vent clusters , while the NPS vehicle - ARIES will reaquire vent... cluster locations and perform close in data gathering. OBJECTIVES The IST has recently been approved to conduct a mission in the Azores (the AZIMOV...the Azores containing hydrothermal vents. The waters are shallow (10 - 20 meters) and large clusters of these vents are known to exist. While there is

  4. Groundwater-Mining-Induced Subsidence and Earth Fissures in Cedar Valley, Southwestern Utah

    NASA Astrophysics Data System (ADS)

    Knudsen, T. R.; Inkenbrandt, P.; Lund, W. R.; Lowe, M.; Bowman, S. D.

    2014-12-01

    Groundwater pumping in excess of recharge (groundwater mining) has lowered the potentiometric surface in Cedar Valley, southwestern Utah, by as much as 114 feet since 1939. Lowering the potentiometric surface (head decline) has caused permanent compaction of fine-grained sediments of the Cedar Valley aquifer. Recently acquired interferometric synthetic aperture radar (InSAR) imagery shows that land subsidence is occurring over an ~100 square-mile area, including two pronounced subsidence bowls in the northeastern (Enoch graben) and southwestern (Quichapa Lake area) parts of the valley. A lack of accurate historical benchmark elevation data over much of the valley prevents detailed long-term quantification of subsidence. In response to the land subsidence, earth fissures have formed along the margins of the Enoch graben and north and west of Quichapa Lake. Our initial inventory of Cedar Valley fissures, which relied on aerial-photography analysis, identified 3.9 miles of fissures in 2009. With newly acquired light detection and ranging (LiDAR) coverage in 2011, we more than doubled the total length of mapped fissures to 8.3 miles. Fissures on the west side of the Enoch graben exhibit ongoing vertical surface displacement with rates as high as 1.7 inches/year. The largest Enoch-graben-west fissure has displaced street surfaces, curb and gutter, and sidewalks, and has reversed the flow direction of a sewer line in a partially developed subdivision. Several Cedar Valley fissures are closely associated with, and in some places coincident with, mapped Quaternary faults. While the majority of Cedar Valley fissures are mapped in agricultural areas, continued groundwater mining and resultant subsidence will likely cause existing fissures to lengthen and new fissures to form that may eventually impact other developed areas of the valley.

  5. Annulus fissures are mechanically and chemically conducive to the ingrowth of nerves and blood vessels.

    PubMed

    Stefanakis, Manos; Al-Abbasi, Maan; Harding, Ian; Pollintine, Phillip; Dolan, Patricia; Tarlton, John; Adams, Michael A

    2012-10-15

    Mechanical and biochemical analyses of cadaveric and surgically removed discs. To test the hypothesis that fissures in the annulus of degenerated human discs are mechanically and chemically conducive to the ingrowth of nerves and blood vessels. Discogenic back pain is closely associated with fissures in the annulus fibrosus, and with the ingrowth of nerves and blood vessels. Three complementary studies were performed. First, 15 cadaveric discs that contained a major annulus fissure were subjected to 1 kN compression, while a miniature pressure transducer was pulled through the disc to obtain distributions of matrix compressive stress perpendicular to the fissure axis. Second, Safranin O staining was used to evaluate focal loss of proteoglycans from within annulus fissures in 25 surgically removed disc samples. Third, in 21 cadaveric discs, proteoglycans (sulfated glycosaminoglycans [sGAGs]) and water concentration were measured biochemically in disrupted regions of annulus containing 1 or more fissures, and in adjacent intact regions. Reductions in compressive stress within annulus fissures averaged 36% to 46%, and could have been greater at the fissure axis. Stress reductions were greater in degenerated discs, and were inversely related to nucleus pressure (R(2) = 47%; P = 0.005). Safranin O stain intensity indicated that proteoglycan concentration was typically reduced by 40% at a distance of 600 μm from the fissure axis, and the width of the proteoglycan-depleted zone increased with age (P < 0.006; R(2) = 0.29) and with general proteoglycan loss (P < 0.001; R(2) = 0.32). Disrupted regions of annulus contained 36% to 54% less proteoglycans than adjacent intact regions from the same discs, although water content was reduced only slightly. Annulus fissures provide a low-pressure microenvironment that allows focal proteoglycan loss, leaving a matrix that is conducive to nerve and blood vessel ingrowth.

  6. Why does a mature volcano need new vents? The case of the New Southeast Crater at Etna

    NASA Astrophysics Data System (ADS)

    Acocella, Valerio; Neri, Marco; Behncke, Boris; Bonforte, Alessandro; Del Negro, Ciro; Ganci, Gaetana

    2016-06-01

    Mature volcanoes usually erupt from a persistent summit crater. Permanent shifts in vent location are expected to occur after significant structural variations and are seldom documented. Here we provide such an example that recently occurred at Etna. Eruptive activity at Mount Etna during 2007 focused at the Southeast Crater (SEC), the youngest (formed in 1971) and most active of the four summit craters, and consisted of six paroxysmal episodes. The related erupted volumes, determined by field-based measurements and radiant heat flux curves measured by satellite, totalled 8.67 x 106 m3. The first four episodes occurred, between late-March and early-May, from the summit of the SEC and short fissures on its flanks. The last two episodes occurred, in September and November, from a new vent ("pit crater" or "proto-NSEC") at the SE base of the SEC cone; this marked the definitive demise of the old SEC and the shift to the new vent. The latter, fed by NW-SE striking dikes propagating from the SEC conduit, formed since early 2011 an independent cone (the New Southeast Crater, or "NSEC") at the base of the SEC. Detailed geodetic reconstruction and structural field observations allow defining the surface deformation pattern of Mount Etna in the last decade. These suggest that the NSEC developed under the NE-SW trending tensile stresses on the volcano summit promoted by accelerated instability of the NE flank of the volcano during inflation periods. The development of the NSEC is not only important from a structural point of view, as its formation may also lead to an increase in volcanic hazard. The case of the NSEC at Etna here reported shows how flank instability may control the distribution and impact of volcanism, including the prolonged shift of the summit vent activity in a mature volcano.

  7. Exploring rock fissures: does a specialized root morphology explain endemism on granite outcrops?

    PubMed Central

    Poot, Pieter; Hopper, Stephen D.; van Diggelen, Josepha M.H.

    2012-01-01

    Background and Aims Worldwide, many plant species are confined to open, shallow-soil, rocky habitats. Although several hypotheses have been proposed to explain this habitat specificity, none has been convincing. We suggest that the high level of endemism on shallow soils is related to the edaphic specialization needed to survive in these often extremely drought-prone habitats. Previous research has shown that species endemic to ironstone communities in SW Australia have a specialized root morphology that enhances their chance to access fissures in the underlying rock. Here we test the generality of these findings for species that are confined to a shallow-soil habitat that is of much greater global significance: granite outcrops. Methods We compared temporal and spatial root growth and allocation of three endemic woody perennials of SW Australian granite outcrop communities with those of congeners occurring on nearby deeper soils. Seedlings of all species were grown in 1·2 m long custom-made containers with a transparent bottom that allowed monitoring of root growth over time. Key Results The granite outcrop endemics mostly differed in a predictable way from their congeners from deeper soils. They generally invested a larger portion of their biomass in roots, distributed their roots faster and more evenly over the container and had a lower specific root length. In different species pairs the outcrop endemics achieved their apparent advantage by a different combination of the aforementioned traits. Conclusions Our results are consistent with earlier work, indicating that species restricted to different types of drought-prone shallow-soil communities have undergone similar selection pressures. Although adaptive in their own habitat in terms of obtaining access to fissures in the underlying rock, these root system traits are likely to be maladaptive in deeper soil habitats. Therefore, our results may provide an explanation for the narrow endemism of many shallow

  8. Exploring rock fissures: does a specialized root morphology explain endemism on granite outcrops?

    PubMed

    Poot, Pieter; Hopper, Stephen D; van Diggelen, Josepha M H

    2012-07-01

    Worldwide, many plant species are confined to open, shallow-soil, rocky habitats. Although several hypotheses have been proposed to explain this habitat specificity, none has been convincing. We suggest that the high level of endemism on shallow soils is related to the edaphic specialization needed to survive in these often extremely drought-prone habitats. Previous research has shown that species endemic to ironstone communities in SW Australia have a specialized root morphology that enhances their chance to access fissures in the underlying rock. Here we test the generality of these findings for species that are confined to a shallow-soil habitat that is of much greater global significance: granite outcrops. We compared temporal and spatial root growth and allocation of three endemic woody perennials of SW Australian granite outcrop communities with those of congeners occurring on nearby deeper soils. Seedlings of all species were grown in 1·2 m long custom-made containers with a transparent bottom that allowed monitoring of root growth over time. The granite outcrop endemics mostly differed in a predictable way from their congeners from deeper soils. They generally invested a larger portion of their biomass in roots, distributed their roots faster and more evenly over the container and had a lower specific root length. In different species pairs the outcrop endemics achieved their apparent advantage by a different combination of the aforementioned traits. Our results are consistent with earlier work, indicating that species restricted to different types of drought-prone shallow-soil communities have undergone similar selection pressures. Although adaptive in their own habitat in terms of obtaining access to fissures in the underlying rock, these root system traits are likely to be maladaptive in deeper soil habitats. Therefore, our results may provide an explanation for the narrow endemism of many shallow-soil endemics.

  9. Electrochemical cell having improved pressure vent

    DOEpatents

    Dean, Kevin; Holland, Arthur; Fillmore, Donn

    1993-01-01

    The electrochemical cell of the instant invention includes a case having a gas outlet, one or more positive electrodes positioned within the case, one or more negative electrodes positioned within the case electrode separators positioned between the positive and negative electrodes, electrolyte positioned within the case, and a pressure vent for releasing internal pressure occurring in the case to the surrounding atmosphere. The pressure vent is affixed to the case covering the gas outlet, the pressure vent includes a vent housing having a hollow interior area in gaseous communication with the surrounding atmosphere and the interior of the case via the gas outlet, a pressure release piston positioned within the hollow interior area, the pressure release piston sized to surround the gas outlet and having a seal groove configured to encapsulate all but one surface of a seal mounted within the seal groove, leaving the non-encapsulated surface of the seal exposed, and a compression spring positioned to urge the pressure release piston to compress the seal in the seal groove and block the gas outlet in the case.

  10. Computer controlled vent and pressurization system

    NASA Technical Reports Server (NTRS)

    Cieslewicz, E. J.

    1975-01-01

    The Centaur space launch vehicle airborne computer, which was primarily used to perform guidance, navigation, and sequencing tasks, was further used to monitor and control inflight pressurization and venting of the cryogenic propellant tanks. Computer software flexibility also provided a failure detection and correction capability necessary to adopt and operate redundant hardware techniques and enhance the overall vehicle reliability.

  11. Preoperational test report, vent building ventilation system

    SciTech Connect

    Clifton, F.T.

    1997-11-04

    This represents a preoperational test report for Vent Building Ventilation Systems, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The system provides Heating, Ventilation, and Air Conditioning (HVAC) for the W-030 Ventilation Building. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System.

  12. Light at deep-sea hydrothermal vents

    NASA Astrophysics Data System (ADS)

    Van Dover, Cindy Lee; Reynolds, George T.; Chave, Alan D.; Tyson, J. Anthony

    Ambient light spectral data were acquired at two deep-sea hydrothermal vents with a temperature of ˜350°C: the Hole-to-Hell site on the East Pacific Rise at 9°N and the Snake-Pit site on the Mid-Atlantic Ridge. Measurements were made with a simple, multi-channel photometer which simultaneously detected light in four 100 nm-wide bands over the wavelength range of 650-1050 nm. Most of the light detected is near-infrared (750-1050 nm), but there is a 19x greater photon flux than expected from thermal radiation alone at shorter wavelengths (650-750 nm) at the Hole-to-Hell vent. At Snake Pit, more light in the 750-850 nm band was observed 10 cm above the orifice where the temperature was 50-100°C than at the 351°C vent opening. These data suggest the presence of non-thermal light sources in the vent environment. Some possible non-thermal mechanisms are identified, but further data will be required to resolve them.

  13. 46 CFR 98.25-70 - Venting.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Venting. 98.25-70 Section 98.25-70 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS SPECIAL CONSTRUCTION, ARRANGEMENT, AND OTHER PROVISIONS FOR CERTAIN DANGEROUS CARGOES IN BULK Anhydrous Ammonia in Bulk § 98.25-70...

  14. 46 CFR 98.25-70 - Venting.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Venting. 98.25-70 Section 98.25-70 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS SPECIAL CONSTRUCTION, ARRANGEMENT, AND OTHER PROVISIONS FOR CERTAIN DANGEROUS CARGOES IN BULK Anhydrous Ammonia in Bulk § 98.25-70...

  15. 46 CFR 98.25-70 - Venting.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Venting. 98.25-70 Section 98.25-70 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS SPECIAL CONSTRUCTION, ARRANGEMENT, AND OTHER PROVISIONS FOR CERTAIN DANGEROUS CARGOES IN BULK Anhydrous Ammonia in Bulk § 98.25-70...

  16. 46 CFR 98.25-70 - Venting.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Venting. 98.25-70 Section 98.25-70 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS SPECIAL CONSTRUCTION, ARRANGEMENT, AND OTHER PROVISIONS FOR CERTAIN DANGEROUS CARGOES IN BULK Anhydrous Ammonia in Bulk § 98.25-70...

  17. 46 CFR 98.25-70 - Venting.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Venting. 98.25-70 Section 98.25-70 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS SPECIAL CONSTRUCTION, ARRANGEMENT, AND OTHER PROVISIONS FOR CERTAIN DANGEROUS CARGOES IN BULK Anhydrous Ammonia in Bulk § 98.25-70...

  18. Flow fields of low pressure vent exhausts

    NASA Technical Reports Server (NTRS)

    Scialdone, John J.

    1989-01-01

    The flow field produced by low pressure gas vents are described based on experimental data obtained from tests in a large vacuum chamber. The gas density, pressure, and flux at any location in the flow field are calculated based on the vent plume description and the knowledge of the flow rate and velocity of the venting gas. The same parameters and the column densities along a specified line of sight traversing the plume are also obtained and shown by a computer-generated graphical representation. The fields obtained with a radially scanning Pitot probe within the exhausting gas are described by a power of the cosine function, the mass rate and the distance from the exit port. The field measurements were made for gas at pressures ranging from 2 to 50 torr venting from pipe fittings with diameters of 3/16 inch to 1-1/2 inches I.D. (4.76 mm to 38.1 mm). The N(2) mass flow rates ranged from 2E-4 to 3.7E-1 g/s.

  19. Flow fields of low pressure vent exhausts

    NASA Technical Reports Server (NTRS)

    Scialdone, John J.

    1990-01-01

    The flow field produced by low pressure gas vents are described based on experimental data obtained from tests in a large vacuum chamber. The gas density, pressure, and flux at any location in the flow field are calculated based on the vent plume description and the knowledge of the flow rate and velocity of the venting gas. The same parameters and the column densities along a specified line of sight traversing the plume are also obtained and shown by a computer generated graphical representation. The fields obtained with a radically scanning Pitot probe within the exhausting gas are described by a power of the cosine function, the mass rate, and the distance from the exit port. The field measurements were made for gas at pressures ranging from 2 to 50 torr venting from pipe fittings with diameters to 3/16 to 1-1/2 inches I.D. (4.76 to 38.1 mm). The N2 mass flow rates ranged from 2E-4 to 3.7E-1 g/s.

  20. 14 CFR 23.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... be arranged to prevent the loss of fuel, except fuel discharged because of thermal expansion, when... from the top part of the expansion space. In addition— (1) Each vent outlet must be located and...

  1. 14 CFR 23.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... be arranged to prevent the loss of fuel, except fuel discharged because of thermal expansion, when... from the top part of the expansion space. In addition— (1) Each vent outlet must be located and...

  2. 14 CFR 23.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... be arranged to prevent the loss of fuel, except fuel discharged because of thermal expansion, when... from the top part of the expansion space. In addition— (1) Each vent outlet must be located and...

  3. 14 CFR 23.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... be arranged to prevent the loss of fuel, except fuel discharged because of thermal expansion, when... from the top part of the expansion space. In addition— (1) Each vent outlet must be located and...

  4. 14 CFR 27.975 - Fuel tank vents.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Fuel tank vents. 27.975 Section 27.975... STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Fuel System § 27.975 Fuel tank vents. (a) Each fuel tank... system must be designed to minimize spillage of fuel through the vents to an ignition source in the...

  5. 33 CFR 183.520 - Fuel tank vent systems.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Fuel tank vent systems. 183.520...) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Equipment Standards § 183.520 Fuel tank vent systems. (a) Each fuel tank must have a vent system that prevents pressure in the tank from exceeding...

  6. 40 CFR 63.1406 - Reactor batch process vent provisions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 11 2011-07-01 2011-07-01 false Reactor batch process vent provisions... § 63.1406 Reactor batch process vent provisions. (a) Emission standards. Owners or operators of reactor... reactor batch process vent located at a new affected source shall control organic HAP emissions...

  7. 40 CFR 63.1406 - Reactor batch process vent provisions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 11 2010-07-01 2010-07-01 true Reactor batch process vent provisions... § 63.1406 Reactor batch process vent provisions. (a) Emission standards. Owners or operators of reactor... reactor batch process vent located at a new affected source shall control organic HAP emissions...

  8. 33 CFR 183.520 - Fuel tank vent systems.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Fuel tank vent systems. 183.520...) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Equipment Standards § 183.520 Fuel tank vent systems. (a) Each fuel tank must have a vent system that prevents pressure in the tank from exceeding...

  9. 40 CFR 63.1408 - Aggregate batch vent stream provisions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 11 2010-07-01 2010-07-01 true Aggregate batch vent stream provisions... § 63.1408 Aggregate batch vent stream provisions. (a) Emission standards. Owners or operators of aggregate batch vent streams at a new or existing affected source shall comply with either paragraph...

  10. 40 CFR 63.1408 - Aggregate batch vent stream provisions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 11 2011-07-01 2011-07-01 false Aggregate batch vent stream provisions... § 63.1408 Aggregate batch vent stream provisions. (a) Emission standards. Owners or operators of aggregate batch vent streams at a new or existing affected source shall comply with either paragraph...

  11. 40 CFR 264.1032 - Standards: Process vents.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 25 2010-07-01 2010-07-01 false Standards: Process vents. 264.1032 Section 264.1032 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES... Air Emission Standards for Process Vents § 264.1032 Standards: Process vents. (a) The owner...

  12. 40 CFR 264.1032 - Standards: Process vents.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 26 2011-07-01 2011-07-01 false Standards: Process vents. 264.1032 Section 264.1032 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES... Air Emission Standards for Process Vents § 264.1032 Standards: Process vents. (a) The owner...

  13. 40 CFR 264.1032 - Standards: Process vents.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 27 2012-07-01 2012-07-01 false Standards: Process vents. 264.1032 Section 264.1032 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES... Air Emission Standards for Process Vents § 264.1032 Standards: Process vents. (a) The owner...

  14. 40 CFR 264.1032 - Standards: Process vents.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 26 2014-07-01 2014-07-01 false Standards: Process vents. 264.1032 Section 264.1032 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES... Air Emission Standards for Process Vents § 264.1032 Standards: Process vents. (a) The owner...

  15. 40 CFR 264.1032 - Standards: Process vents.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 27 2013-07-01 2013-07-01 false Standards: Process vents. 264.1032 Section 264.1032 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES... Air Emission Standards for Process Vents § 264.1032 Standards: Process vents. (a) The owner...

  16. 46 CFR 56.50-85 - Tank-vent piping.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... liquids, such as lubricating oil, may terminate in the machinery space, provided— (i) The vents are... of the tanks to vent pipes. (2) Tanks having a comparatively small surface, such as fuel oil settling... under any service condition. (3) Vent pipes for fuel oil tanks shall, wherever possible, have a slope of...

  17. 46 CFR 56.50-85 - Tank-vent piping.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... liquids, such as lubricating oil, may terminate in the machinery space, provided— (i) The vents are... of the tanks to vent pipes. (2) Tanks having a comparatively small surface, such as fuel oil settling... under any service condition. (3) Vent pipes for fuel oil tanks shall, wherever possible, have a slope of...

  18. 46 CFR 56.50-85 - Tank-vent piping.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... liquids, such as lubricating oil, may terminate in the machinery space, provided— (i) The vents are... of the tanks to vent pipes. (2) Tanks having a comparatively small surface, such as fuel oil settling... under any service condition. (3) Vent pipes for fuel oil tanks shall, wherever possible, have a slope of...

  19. 46 CFR 56.50-85 - Tank-vent piping.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... liquids, such as lubricating oil, may terminate in the machinery space, provided— (i) The vents are... of the tanks to vent pipes. (2) Tanks having a comparatively small surface, such as fuel oil settling... under any service condition. (3) Vent pipes for fuel oil tanks shall, wherever possible, have a slope of...

  20. 46 CFR 182.450 - Vent pipes for fuel tanks.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Vent pipes for fuel tanks. 182.450 Section 182.450... TONS) MACHINERY INSTALLATION Specific Machinery Requirements § 182.450 Vent pipes for fuel tanks. (a) Each unpressurized fuel tank must be fitted with a vent pipe connected to the highest point of the...

  1. 46 CFR 153.463 - Vent system discharges.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Vent system discharges. 153.463 Section 153.463 Shipping... Requirements for Flammable Or Combustible Cargoes § 153.463 Vent system discharges. The discharge of a venting system must be at least 10 m (approx. 32.8 ft) from an ignition source if: (a) The cargo tank is...

  2. 40 CFR 63.1429 - Process vent monitoring requirements.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 11 2011-07-01 2011-07-01 false Process vent monitoring requirements....1429 Process vent monitoring requirements. (a) Monitoring equipment requirements. The owner or operator... vent control requirements in § 63.1425(b)(1), (b)(2), (c)(1), (c)(3), or (d) shall install...

  3. 14 CFR 121.261 - Vent and drain lines.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Vent and drain lines. 121.261 Section 121... drain lines. All vent and drain lines and their fittings, that are located in a designated fire zone... the rupture or breakage of any vent or drain line may result in a fire hazard. ...

  4. 14 CFR 34.11 - Standard for fuel venting emissions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... FUEL VENTING AND EXHAUST EMISSION REQUIREMENTS FOR TURBINE ENGINE POWERED AIRPLANES Engine Fuel Venting Emissions (New and In-Use Aircraft Gas Turbine Engines) § 34.11 Standard for fuel venting emissions. (a) No... turbine engine subject to the subpart. This paragraph is directed at the elimination of...

  5. 14 CFR 34.11 - Standard for fuel venting emissions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... FUEL VENTING AND EXHAUST EMISSION REQUIREMENTS FOR TURBINE ENGINE POWERED AIRPLANES Engine Fuel Venting Emissions (New and In-Use Aircraft Gas Turbine Engines) § 34.11 Standard for fuel venting emissions. (a) No... turbine engine subject to the subpart. This paragraph is directed at the elimination of...

  6. 40 CFR 63.1405 - Continuous process vent provisions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 11 2010-07-01 2010-07-01 true Continuous process vent provisions. 63... Standards for Hazardous Air Pollutant Emissions: Manufacture of Amino/Phenolic Resins § 63.1405 Continuous process vent provisions. (a) Emission standards. For each continuous process vent located at a new...

  7. Chronology and volcanology of the 1949 multi-vent rift-zone eruption on La Palma (Canary Islands)

    NASA Astrophysics Data System (ADS)

    Klügel, A.; Schmincke, H.-U.; White, J. D. L.; Hoernle, K. A.

    1999-12-01

    The compositionally zoned San Juan eruption on La Palma emanated from three eruptive centers located along a north-south-trending rift zone in the south of the island. Seismic precursors began weakly in 1936 and became strong in March 1949, with their foci progressing from the north of the rift zone towards its south. This suggests that magma ascended beneath the old Taburiente shield volcano and moved southward along the rift. The eruption began on June 24, 1949, with phreatomagmatic activity at Duraznero crater on the ridgetop (ca. 1880 m above sea level), where five vents erupted tephritic lava along a 400-m-long fissure. On June 8, the Duraznero vents shut down abruptly, and the activity shifted to an off-rift fissure at Llano del Banco, located at ca. 550 m lower elevation and 3 km to the northwest. This eruptive center issued initially tephritic aa and later basanitic pahoehoe lava at high rates, producing a lava flow that entered the sea. Two days after basanite began to erupt at Llano del Banco, Hoyo Negro crater (ca. 1880 m asl), located 700 m north of Duraznero along the rift, opened on July 12 and produced ash and bombs of basanitic to phonotephritic composition in violent phreatomagmatic explosions ( White and Schmincke, 1999). Llano del Banco and Hoyo Negro were simultaneously active for 11 days and showed a co-variance of their eruption rates indicating a shallow hydraulic connection. On July 30, after 3 days of quiescence at all vents, Duraznero and Hoyo Negro became active again during a final eruptive phase. Duraznero issued basanitic lava at high rates for 12 h and produced a lava flow that descended towards the east coast. The lava contains ca. 1 vol.% crustal and mantle xenoliths consisting of 40% tholeiitic gabbros from the oceanic crust, 35% alkaline gabbros, and 20% ultramafic cumulates. The occurrence of xenoliths almost exclusively in the final lava is consistent with their origin by wall-rock collapse at depth near the end of the eruption

  8. Discovery of a black smoker vent field and vent fauna at the Arctic Mid-Ocean Ridge

    PubMed Central

    Pedersen, Rolf B.; Rapp, Hans Tore; Thorseth, Ingunn H.; Lilley, Marvin D.; Barriga, Fernando J. A. S.; Baumberger, Tamara; Flesland, Kristin; Fonseca, Rita; Früh-Green, Gretchen L.; Jorgensen, Steffen L.

    2010-01-01

    The Arctic Mid-Ocean Ridge (AMOR) represents one of the most slow-spreading ridge systems on Earth. Previous attempts to locate hydrothermal vent fields and unravel the nature of venting, as well as the provenance of vent fauna at this northern and insular termination of the global ridge system, have been unsuccessful. Here, we report the first discovery of a black smoker vent field at the AMOR. The field is located on the crest of an axial volcanic ridge (AVR) and is associated with an unusually large hydrothermal deposit, which documents that extensive venting and long-lived hydrothermal systems exist at ultraslow-spreading ridges, despite their strongly reduced volcanic activity. The vent field hosts a distinct vent fauna that differs from the fauna to the south along the Mid-Atlantic Ridge. The novel vent fauna seems to have developed by local specialization and by migration of fauna from cold seeps and the Pacific. PMID:21119639

  9. Discovery of a black smoker vent field and vent fauna at the Arctic Mid-Ocean Ridge.

    PubMed

    Pedersen, Rolf B; Rapp, Hans Tore; Thorseth, Ingunn H; Lilley, Marvin D; Barriga, Fernando J A S; Baumberger, Tamara; Flesland, Kristin; Fonseca, Rita; Früh-Green, Gretchen L; Jorgensen, Steffen L

    2010-11-23

    The Arctic Mid-Ocean Ridge (AMOR) represents one of the most slow-spreading ridge systems on Earth. Previous attempts to locate hydrothermal vent fields and unravel the nature of venting, as well as the provenance of vent fauna at this northern and insular termination of the global ridge system, have been unsuccessful. Here, we report the first discovery of a black smoker vent field at the AMOR. The field is located on the crest of an axial volcanic ridge (AVR) and is associated with an unusually large hydrothermal deposit, which documents that extensive venting and long-lived hydrothermal systems exist at ultraslow-spreading ridges, despite their strongly reduced volcanic activity. The vent field hosts a distinct vent fauna that differs from the fauna to the south along the Mid-Atlantic Ridge. The novel vent fauna seems to have developed by local specialization and by migration of fauna from cold seeps and the Pacific.

  10. Evidence for Hydrothermal Vents as "Biogeobatteries" (Invited)

    NASA Astrophysics Data System (ADS)

    Nielsen, M. E.; Girguis, P. R.

    2010-12-01

    Hydrothermal vents are unique systems that play an important role in oceanic biogeochemical cycles. As chemically reduced hydrothermal fluid mixes with cold oxic seawater, minerals precipitate out of solution resulting in chimney structures composed largely of metal sulfides and anhydrite. Pyrite, which is a natural semi-conductor, is the primary sulfide mineral, but other minerals within chimneys are also conductive (e.g. chalcopyrite, wurtzite, and some iron oxides). Sulfide chimneys are also known to host an extensive endolithic microbial community. Accordingly, submarine hydrothermal systems appear to be examples of biogeobatteries, wherein conductive mineral assemblages span naturally occuring redox gradients and enable anaerobic microbes to access oxygen as an oxidant via extracellular electron transfer (or EET). To test this hypothesis, we ran a series of electrochemical laboratory experiments in which pyrite was used as an anode (in a vessel flushed with hydrothermal-like fluid). When placed in continuity with a carbon fiber cathode, pyrite was found to accept and conduct electrons from both abiotic and biological processes (microbial EET). Specifically, electrical current increased 4-fold (5 nA/m2 to 20 nA/m2) in response to inoculation with a slurry prepared from a hydrothermal vent sample. Inspection of the pyrite anode with SEM revealed ubiquitous coverage by microbes. DNA was extracted from the anodes and the inoculum, and was subjected to pyrosequencing to examine prokaryotic diversity. These data suggest that key microbial phylotypes were enriched upon the pyrite, implicating them in EET. In addition, we deployed an in situ experiment based on microbial fuel cell architecture with a graphite anode inserted into a vent wall coupled to a carbon fiber cathode outside the vent. We observed current production over the course of one year, implying microbial EET in situ. Via pyrosequencing, we observed that the microbial community on the anode was

  11. Discrete element modeling on the crack evolution behavior of brittle sandstone containing three fissures under uniaxial compression

    NASA Astrophysics Data System (ADS)

    Yang, Sheng-Qi; Huang, Yan-Hua; Ranjith, P. G.; Jiao, Yu-Yong; Ji, Jian

    2015-12-01

    Based on experimental results of brittle, intact sandstone under uniaxial compression, the micro-parameters were firstly confirmed by adopting particle flow code (PFC^{2D}). Then, the validation of the simulated models were cross checked with the experimental results of brittle sandstone containing three parallel fissures under uniaxial compression. The simulated results agreed very well with the experimental results, including the peak strength, peak axial strain, and ultimate failure mode. Using the same micro-parameters, the numerical models containing a new geometry of three fissures are constructed to investigate the fissure angle on the fracture mechanical behavior of brittle sandstone under uniaxial compression. The strength and deformation parameters of brittle sandstone containing new three fissures are dependent to the fissure angle. With the increase of the fissure angle, the elastic modulus, the crack damage threshold, and the peak strength of brittle sandstone containing three fissures firstly increase and secondly decrease. But the peak axial strain is nonlinearly related to the fissure angle. In the entire process of deformation, the crack initiation and propagation behavior of brittle sandstone containing three fissures under uniaxial compression are investigated with respect to the fissure angle. Six different crack coalescence modes are identified for brittle sandstone containing three fissures under uniaxial compression. The influence of the fissure angle on the length of crack propagation and crack coalescence stress is evaluated. These investigated conclusions are very important for ensuring the stability and safety of rock engineering with intermittent structures.

  12. Evidence not practised: the underutilisation of preventive fissure sealants.

    PubMed

    Bonetti, D L

    2014-04-01

    International and UK professional organisations, Cochrane systematic reviews, and international and UK guidance documents all support the application of preventive fissure sealants (PFSs) as an effective treatment for reducing caries. However, PFSs are well known to be underutilised in primary care. This paper collates data from PFS-relevant studies in Scotland, which has a large population of children at caries risk, to identify the beliefs and factors dentists perceive as influencing their decision not to provide this treatment. This information provides a platform to suggest how to increase the application of PFSs in this region (a standardised audit incorporating evidence-based behaviour change techniques, supplemental guidance on how to implement gold-standard recommendations in practice, training). This may also be relevant outside of Scotland, as well as to the implementation of other evidence-based behaviours in practice.

  13. Superior orbital fissure syndrome in herpes zoster ophthalmicus.

    PubMed

    Kirwan, R P; Abdalla, M; Hogan, A; Tubridy, N; Barry, P; Power, W

    2009-09-01

    To report a case of superior orbital fissure syndrome (SOFS) in a patient with herpes zoster ophthalmicus (HZO). A case report. A 71-year-old male with HZO presented acutely to accident and emergency complaining of right vision loss, double vision and drowsiness. The right visual acuity was counting fingers. There was no relative afferent pupillary defect. He had interstitial keratitis, ptosis, proptosis and total ophthalmoplaegia. The signs indicated HZO complicated by SOFS. Brain imaging and lumbar puncture confirmed the diagnosis of varicella zoster encephalitis. Systemic acyclovir and prednisolone led to recovery of visual acuity and ocular motility in addition to resolution of his proptosis and ptosis. SOFS is a rare complication of herpes zoster infection. With the appropriate treatment and follow-up, patients may be reassured that recovery of their visual acuity and ocular motility will occur.

  14. Fissure sealant materials: Wear resistance of flowable composite resins

    PubMed Central

    Asefi, Sohrab; Eskandarion, Solmaz; Hamidiaval, Shadi

    2016-01-01

    Background. Wear resistance of pit and fissure sealant materials can influence their retention. Wear characteristics of sealant materials may determine scheduling of check-up visits. The aim of this study was to compare wear resistance of two flowable composite resins with that of posterior composite resin materials. Methods. Thirty-five disk-shaped specimens were prepared in 5 groups, including two flowable composite resins (Estelite Flow Quick and Estelite Flow Quick High Flow), Filtek P90 and Filtek P60 and Tetric N-Ceram. The disk-shaped samples were prepared in 25-mm diameter by packing them into a two-piece aluminum mold and then light-cured. All the specimens were polished for 1minute using 600-grit sand paper. The samples were stored in distilled water at room temperature for 1 week and then worn by two-body abrasion test using "pin-on-disk" method (with distilled water under a 15-Nload at 0.05 m/s, for a distance of 100 meter with Steatite ceramic balls antagonists). A Profilometer was used for evaluating the surface wear. Data were analyzed with the one-way ANOVA. Results. Estelite Flow Quick exhibited 2708.9 ± 578.1 μm2 and Estelite Flow Quick High Flow exhibited 3206 ± 2445.1 μm2of wear but there were no significant differences between the groups. They demonstrated similar wear properties. Conclusion. Estelite flowable composite resins have wear resistance similar to nano- and micro-filled and micro-hybrid composite resins. Therefore, they can be recommended as pit and fissure sealant materials in the posterior region with appropriate mechanical characteristics. PMID:27651887

  15. Fissure sealant materials: Wear resistance of flowable composite resins.

    PubMed

    Asefi, Sohrab; Eskandarion, Solmaz; Hamidiaval, Shadi

    2016-01-01

    Background. Wear resistance of pit and fissure sealant materials can influence their retention. Wear characteristics of sealant materials may determine scheduling of check-up visits. The aim of this study was to compare wear resistance of two flowable composite resins with that of posterior composite resin materials. Methods. Thirty-five disk-shaped specimens were prepared in 5 groups, including two flowable composite resins (Estelite Flow Quick and Estelite Flow Quick High Flow), Filtek P90 and Filtek P60 and Tetric N-Ceram. The disk-shaped samples were prepared in 25-mm diameter by packing them into a two-piece aluminum mold and then light-cured. All the specimens were polished for 1minute using 600-grit sand paper. The samples were stored in distilled water at room temperature for 1 week and then worn by two-body abrasion test using "pin-on-disk" method (with distilled water under a 15-Nload at 0.05 m/s, for a distance of 100 meter with Steatite ceramic balls antagonists). A Profilometer was used for evaluating the surface wear. Data were analyzed with the one-way ANOVA. Results. Estelite Flow Quick exhibited 2708.9 ± 578.1 μm(2) and Estelite Flow Quick High Flow exhibited 3206 ± 2445.1 μm(2)of wear but there were no significant differences between the groups. They demonstrated similar wear properties. Conclusion. Estelite flowable composite resins have wear resistance similar to nano- and micro-filled and micro-hybrid composite resins. Therefore, they can be recommended as pit and fissure sealant materials in the posterior region with appropriate mechanical characteristics.

  16. Pleistocene microvertebrates from fissure-fillings in Thailand

    NASA Astrophysics Data System (ADS)

    Chaimanee, Yaowalak; Jaeger, Jean-Jacques; Suteethorn, Varavudh

    Microvertebrates (and among them specially, rodents) have contributed to the elaboration of precise biochronological time scales and to the reconstitution of Pleistocene paleoenvironments in several parts of the world (North America, Africa, Europe and Japan). They have been demonstrated to be highly sensitive to climatic changes since they are very sensitive to vegetation changes. Up to now, no data is available for Southeast Asia and very few information is available concerning the nature of climatic changes which affected that part of the tropical world during the Pleistocene. In the past few years, we have discovered several fissure fillings in Thailand yielding numerous remains of microvertebrates which have been extracted by dissolution in acetic acid solution. These deposits are the result of the feeding activity of predators, like owls or diurnal raptors, whose pellets are accumulated in caves or fissures. Eleven localities, located in Central (2), Eastern (1), Western (2) and Peninsular Thailand (6) have been investigated so far. Several rodent species, belonging to 9 genera of Murinae (rats and mice) and 9 genera of Sciuridae (squirrels) have been identified in these localities. The most important differences with the extant representatives often concern the size of the teeth of these fossil species. The meaning of these size differences is not yet clearly understood since they can be attributed either to significant time differences between localities (microevolution) or as the result of size variations related to climatic changes (clinical variations). More data will have to be collected to calibrate the temporal frame. Already, important modification of the geographic distribution of some species have been discovered which testify that during the Pleistocene, significative climatic changes have affected Southeast Asia. For example, Exilisciurus, a squirrel which is presently restricted to Borneo has been recognized in Peninsular Thailand. Also, Iomys

  17. An Unusual Stress Metabolite from a Hydrothermal Vent Fungus Aspergillus sp. WU 243 Induced by Cobalt.

    PubMed

    Ding, Chihong; Wu, Xiaodan; Auckloo, Bibi Nazia; Chen, Chen-Tung Arthur; Ye, Ying; Wang, Kuiwu; Wu, Bin

    2016-01-16

    A novel hybrid polyketide-terpenoid, aspergstressin (1), possessing a unique fused polycyclic structure, was induced from culture broth of strain Aspergillus sp. WU 243 by cobalt ion stimulation. The strain was isolated from the digestive gland of Xenograpsus testudinatus, a unique type of crab which dwells in the Kueishantao hydrothermal vents off Taiwan. The chemical structure and relative configuration of the stress metabolite were established by spectroscopic means. Aspergillus sp. WU 243 produced aspergstressin (1) only under cobalt stressed culture conditions. The results show that stress-driven discovery of new natural products from hydrothermal vent fungi is an effective strategy to unveil the untapped reservoir of small molecules from species found in the hydrothermal vent environment.

  18. Modeling of earth fissures caused by land subsidence due to groundwater withdrawal

    NASA Astrophysics Data System (ADS)

    Panda, B. B.; Rucker, M. L.; Fergason, K. C.

    2015-11-01

    Land subsidence and earth fissures are phenomena related to groundwater withdrawal in a sedimentary basin. If the rock basement or basin lithology is irregular, both vertical and horizontal displacements can be induced due to differential settlement and tensile stresses appearing in the soil mass. If the differential settlement is of sufficient magnitude, earth fissuring can occur within tensile zones. The magnitudes of compaction and fissure geometry are closely related to the thickness and skeletal compressibility of fine-grained sediments within the aquifer system. Land subsidence and earth fissuring were modeled by employing a two-dimensional (2-D) coupled seepage and stress-strain finite element analysis. The basin bedrock geometry, lithological variation, measurements of surface displacements, and changes in hydraulic head were the critical input parameter for the subsidence modeling. Simulation results indicate that strain had exceeded the approximate threshold for fissure formation of 0.02 to 0.06 % in the area of the identified fissures. The numerical model was used to predict future subsidence and potential earth fissures for flood control structures within the metro Phoenix area.

  19. Infrasound from the 2007 fissure eruptions of Kīlauea Volcano, Hawai'i

    USGS Publications Warehouse

    Fee, D.; Garces, M.; Orr, T.; Poland, M.

    2011-01-01

    Varied acoustic signals were recorded at Kīlauea Volcano in mid-2007, coincident with dramatic changes in the volcano's activity. Prior to this time period, Pu'u 'Ō'ō crater produced near-continuous infrasonic tremor and was the primary source of degassing and lava effusion at Kīlauea. Collapse and draining of Pu'u 'Ō'ō crater in mid-June produced impulsive infrasonic signals and fluctuations in infrasonic tremor. Fissure eruptions on 19 June and 21 July were clearly located spatially and temporally using infrasound arrays. The 19 June eruption from a fissure approximately mid-way between Kīlauea's summit and Pu'u 'O'o produced infrasound for ~30 minutes-the only observed geophysical signal associated with the fissure opening. The infrasound signal from the 21 July eruption just east of Pu'u 'Ō'ō shows a clear azimuthal progression over time, indicative of fissure propagation over 12.9 hours. The total fissure propagation rate is relatively slow at 164 m/hr, although the fissure system ruptured discontinuously. Individual fissure rupture times are estimated using the acoustic data combined with visual observations.

  20. Modelling hydrothermal venting in volcanic sedimentary basins: Impact on hydrocarbon maturation and paleoclimate

    NASA Astrophysics Data System (ADS)

    Iyer, Karthik; Schmid, Daniel W.; Planke, Sverre; Millett, John

    2017-06-01

    Vent structures are intimately associated with sill intrusions in sedimentary basins globally and are thought to have been formed contemporaneously due to overpressure generated by gas generation during thermogenic breakdown of kerogen or boiling of water. Methane and other gases generated during this process may have driven catastrophic climate change in the geological past. In this study, we present a 2D FEM/FVM model that accounts for 'explosive' vent formation by fracturing of the host rock based on a case study in the Harstad Basin, offshore Norway. Overpressure generated by gas release during kerogen breakdown in the sill thermal aureole causes fracture formation. Fluid focusing and overpressure migration towards the sill tips results in vent formation after only few tens of years. The size of the vent depends on the region of overpressure accessed by the sill tip. Overpressure migration occurs in self-propagating waves before dissipating at the surface. The amount of methane generated in the system depends on TOC content and also on the type of kerogen present in the host rock. Generated methane moves with the fluids and vents at the surface through a single, large vent structure at the main sill tip matching first-order observations. Violent degassing takes place within the first couple of hundred years and occurs in bursts corresponding to the timing of overpressure waves. The amount of methane vented through a single vent is only a fraction (between 5 and 16%) of the methane generated at depth. Upscaling to the Vøring and Møre Basins, which are a part of the North Atlantic Igneous Province, and using realistic host rock carbon content and kerogen values results in a smaller amount of methane vented than previously estimated for the PETM. Our study, therefore, suggests that the negative carbon isotope excursion (CIE) observed in the fossil record could not have been caused by intrusions within the Vøring and Møre Basins alone and that a contribution

  1. Preferential flow in fissured sediments in desert soils related to radioactive waste disposal

    SciTech Connect

    Scanlon, B.R.; Raney, J.A. . Bureau of Economic Geology)

    1992-01-01

    Unsaturated flow in fissured sediments in the Chihuahuan Desert of Texas was examined to determine if these features act as preferred pathways for water and solute transport. Fissures are surface features, or gulleys, that are underlain by fractures filled with sediment derived from surrounding areas. Hydraulic and chemical approaches were used to investigate unsaturated flow processes beneath and adjacent to fissures, and the results were compared with data from surrounding geomorphic systems such as arroyos, ephemeral streams, and interstreams. Typically, high water potentials in surficial sediments result from infiltration of recent precipitation. Below this surficial zone of high water potentials lies a zone of low water potentials that is much thinner beneath the fissure than in adjacent sediments or in sediments beneath ephemeral streams and interstreams. Maximum chloride concentrations in profiles in the near-surface fissured sediments were much lower than those measured in all other geomorphic systems. The corresponding moisture velocities in the fissured sediments ranged from 10 to 70 mm/yr. A tracer experiment demonstrated higher downward water and solute transport in the fracture fill beneath the fissure relative to adjacent sediments. Numerical simulations of the tracer experiment with the computer code TRACR3D reproduced the overall shape of the tracer plume. Sensitivity analyses demonstrated that the tracer plume is most sensitive to spatial variability in soil texture and the corresponding hydraulic parameters. The results from this study suggest that sediments in the fissured area act as preferred pathways in the shallow subsurface because surface runoff is concentrated in the fissures and because underlying fractures and cavities provide avenues for moisture and solute transport.

  2. Quantitative characterization and micro-CT mineral mapping of natural fissural enamel lesions.

    PubMed

    Shahmoradi, Mahdi; Swain, Michael V

    2016-03-01

    The aim of this study was to characterize the mineral distribution pattern of natural fissural enamel lesions and to quantify structural parameters and mineral density of these lesions in comparison to proximal white spot enamel lesions. Imaging was undertaken using a high-resolution desktop micro-computed tomography system. A calibration equation was used to transform the grey level values of images into true mineral density values. The value of lesion parameters including the mineral density and the thickness of the surface layer of the enamel lesion were extracted from mineral density profiles. The thickness of the surface layer showed variation among different lesions and it ranged from 0-90 μm in proximal lesions and 0-137 μm in fissural lesions. The average thickness of surface layer in fissural lesions was significantly higher than smooth surface proximal lesions. Sound fissural enamel showed lower mineral density compared to proximal enamel. Micro-CT and the suggested de-noising and visualization method provide an efficient high-resolution approach for non-destructive evaluation of fissural lesions. Using these methods, the current study revealed the exclusive pattern and structure of fissural enamel lesions which may provide a basis for future studies on prevention and remineralization of these lesions. The common demineralization pattern of fissural lesions, which indicates the extension of the lesion in two directions towards the pulp horns, may explain the early inflammation and symptoms of the pulp in fissural lesions even when the lesion base appears far from the pulp roof in normal radiographs. In addition, the presence of the surface layer, indicates that vigorous probing of the occlusal fissures may lead to breakage and cavitation of the enamel lesions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Automatic segmentation of pulmonary fissures in x-ray CT images using anatomic guidance

    NASA Astrophysics Data System (ADS)

    Ukil, Soumik; Sonka, Milan; Reinhardt, Joseph M.

    2006-03-01

    The pulmonary lobes are the five distinct anatomic divisions of the human lungs. The physical boundaries between the lobes are called the lobar fissures. Detection of lobar fissure positions in pulmonary X-ray CT images is of increasing interest for the early detection of pathologies, and also for the regional functional analysis of the lungs. We have developed a two-step automatic method for the accurate segmentation of the three pulmonary fissures. In the first step, an approximation of the actual fissure locations is made using a 3-D watershed transform on the distance map of the segmented vasculature. Information from the anatomically labeled human airway tree is used to guide the watershed segmentation. These approximate fissure boundaries are then used to define the region of interest (ROI) for a more exact 3-D graph search to locate the fissures. Within the ROI the fissures are enhanced by computing a ridgeness measure, and this is used as the cost function for the graph search. The fissures are detected as the optimal surface within the graph defined by the cost function, which is computed by transforming the problem to the problem of finding a minimum s-t cut on a derived graph. The accuracy of the lobar borders is assessed by comparing the automatic results to manually traced lobe segments. The mean distance error between manually traced and computer detected left oblique, right oblique and right horizontal fissures is 2.3 +/- 0.8 mm, 2.3 +/- 0.7 mm and 1.0 +/- 0.1 mm, respectively.

  4. Ecology of deep-sea hydrothermal vent communities: A review

    SciTech Connect

    Lutz, R.A.; Kennish, M.J. )

    1993-08-01

    The present article reviews studies of the past 15 years of active and inactive hydrothermal vents. The focus of the discussion is on the ecology of the biological communities inhabiting hydrothermal vents. These communities exhibit high densities and biomass, low species diversity, rapid growth rates, and high metabolic rates. The authors attempt to relate the biology of hydrothermal vent systems to geology. Future directions for hydrothermal vent research are suggested. Since many vent populations are dependent on hydrothermal fluids and are consequently unstable, both short- and long-term aspects of the ecology of the vent organisms and the influence of chemical and geological factors on the biology of vent systems need to be established. 200 refs., 28 figs.

  5. The Problem of Occlusal Surface Pit and Fissure Dental Caries in Naval Recruits.

    DTIC Science & Technology

    1980-06-01

    been little attention devoted to oclusal surface pit and fissure dental caries. There is so= evidence that tooth morphology is related to susceptibility...AD-A0CM 755 NAVAL DENTAL RESEARCH INST GREAT LAKES IL F/S 6/5 THE PROBLEM OF OCCLUSAL SURFACE PIT AND FISSURE DENTAL CARIES I--ETC(U) JUN 80 M R...THE PROBLEM OF OCCLUSAL SURFACE PIT AND FISSURE DENTAL CARIES IN NAVAL RECRUITS M. R. WIRTHLIN 1. L. SHKLAIR R. G. WALTER J. C. CECIL 0 M. E. COHEN

  6. Cassini VIMS Spectra of the Thermal Emission from Hot Spots Along Enceladus South Pole Fissures

    NASA Astrophysics Data System (ADS)

    Goguen, Jay D.; Buratti, Bonnie J.; Cassini VIMS Team

    2016-10-01

    Most of the south pole fissure region has not been directly illuminated by sunlight since the sub-solar point moved into the northern hemisphere in 2009, thereby eliminating the background of reflected sunlight at VIMS wavelengths and making the fissure thermal emission readily measureable. Since then, VIMS has measured spectra of at least 11 hot spots along the fissures. Most of these measurements were acquired in ride-along mode with CIRS as the prime instrument. During at least 2 encounters, VIMS and CIRS acquired simultaneous or near-simultaneous spectra of the same fissure location. VIMS spectra include multiple hot spots along Damascus, Baghdad, Cairo, and a likely hot spot on Alexandria.All of the VIMS spectra examined to date are consistent with this scenario of a self-regulating fissure maximum T~200 K with brighter VIMS emissions corresponding to fissures up to ~20 m wide. Emission from the warm fissure interior walls dominate the VIMS spectra with <15% contributed by conductive heating of the adjacent terrain at VIMS wavelengths.CIRS spectra report slightly cooler T's due to CIRS increased sensitivity to lower T emission at longer wavelengths and averaging over contributions from both the hottest and cooler areas. Combined analysis of the CIRS and VIMS spectra spanning 3 to 500 micron wavelengths promises to reveal the distribution of [T, area] near the fissures that cannot be spatially resolved. This [T, area] distribution holds the key to understanding how heat is transferred to the surface within a few 100 m of the fissures.The VIMS-detected emission is concentrated in localized hot spots along the fissures and does not seem to be distributed continuously along them. CIRS spectra suggest a more continuous distribution of the emission along the fissure length. Jets locations also are distributed along the fissure length and it appears that the VIMS-detected hot spots in general correlate with jet locations, but not all of the jet locations have been

  7. [Fissure sealants as primary preventive measures. Four-year evaluation in Stara Pazova].

    PubMed

    Andjelic, P; Pazova, S; Vojinovic, J; Tatic, E; Pintaric, J

    1991-04-01

    Worldwide studies have shown that fissure caries prophylaxis is very difficult using conventional preventive methods. The scientific council of the prophylaxis programme for the protection of mouth and teeth in Vojvodina has begun sealing fissures in Stara Pazova and Novi Sad. The molars of all 6-year-old children were sealed completely. A 77.8% reduction in fissure caries was found at the end of the four-year study. Losses of sealing material came to 16% after four years. Cost-effectiveness analysis: The sealings are three times cheaper than an amalgam filling. Application time: 8-9 minutes.

  8. Moisture and solute flux along preferred pathways characterized by fissured sediments in desert soils

    NASA Astrophysics Data System (ADS)

    Scanlon, Bridget R.

    1992-06-01

    Evaluation of preferred flow pathways is critical for waste disposal. These pathways reduce the effectiveness of thick desert soils in attenuating contaminants by short-circuiting flow through the unsaturated zone. Unsaturated flow in fissured sediments in the Chihuahuan Desert of Texas, U.S.A., was examined to determine if these sediments act as preferred pathways for water and solute transport. Fissures are surface features, or gulleys, that are underlain by fractures filled with loose sediment washed in from surrounding areas. Hydraulic and chemical approaches were used to investigate unsaturated flow processes beneath and adjacent to fissures, and the results were compared with data from surrounding geomorphic systems such as arroyos, ephemeral streams and interstreams. Typically, high water potentials in surficial sediments result from infiltration of recent precipitation. Below this surficial zone of high water potentials lies a zone of low water potentials that is much thinner beneath the fissure than in adjacent sediments or in sediments beneath ephemeral streams and interstreams. Maximum chloride concentrations in profiles in the fissured sediments (80-105 gm -3) were much lower than those measured in all other geomorphic systems (2000-6000 gm -3) because chloride is leached in the vicinity of the fissures. Minimum estimates of the moisture flux from chloride data ranged from 1 to 8 mm yr -1 in the fissured sediments and were up to 350 times greater than those calculated for ephemeral stream and interstream settings. The corresponding moisture velocities in the fissured sediments ranged from 10 to 70 mm yr -1. A tracer experiment demonstrated higher downward water and solute transport in the fracture fill beneath the fissure relative to adjacent sediments. Numerical simulations of the tracer experiment with the computer code TRACR3D reproduced the overall shape of the tracer plume. Sensitivity analyses demonstrated that the tracer plume is most sensitive

  9. Sparger system for MMH-helium vents

    NASA Technical Reports Server (NTRS)

    Rakow, A.

    1983-01-01

    Based on a calculated vent flow rate and MMH concentration, a TI-59 program was run to determine total sparger hole area for a given sparger inlet pressure. Hole diameter is determined from a mass transfer analysis in the holding tank to achieve complete capture of MMH. In addition, based on oxidation kinetics and vapor pressure data, MMh atmospheric concentrations are determined 2 ft above the holding tank.

  10. Comparative Study of Vented vs. Unvented Crawlspaces

    SciTech Connect

    Biswas, Kaushik; Christian, Jeffrey E; Gehl, Anthony C

    2011-10-01

    There has been a significant amount of research in the area of building energy efficiency and durability. However, well-documented quantitative information on the impact of crawlspaces on the performance of residential structures is lacking. The objective of this study was to evaluate and compare the effects of two crawlspace strategies on the whole-house performance of a pair of houses in a mixed humid climate. These houses were built with advanced envelope systems to provide energy savings of 50% or more compared to traditional 2010 new construction. One crawlspace contains insulated walls and is sealed and semi-conditioned. The other is a traditional vented crawlspace with insulation in the crawlspace ceiling. The vented (traditional) crawlspace contains fiberglass batts installed in the floor chase cavities above the crawl, while the sealed and insulated crawlspace contains foil-faced polyisocyanurate foam insulation on the interior side of the masonry walls. Various sensors to measure temperatures, heat flux through crawlspace walls and ceiling, and relative humidity were installed in the two crawlspaces. Data from these sensors have been analyzed to compare the performance of the two crawlspace designs. The analysis results indicated that the sealed and insulated crawlspace design is better than the traditional vented crawlspace in the mixed humid climate.

  11. Identification of possible recent water/lava source fissures in the Cerberus Plains: stratigraphic and crater count age constraints

    NASA Astrophysics Data System (ADS)

    Thomas, Rebecca J.

    2013-04-01

    The Cerberus plains are one of the youngest surfaces on Mars. They are thought to have been formed by lava and/or water flows, but there is considerable debate regarding the source of this material. Much of the material forming the western plains, including the Athabasca Valles outflow channels, appears to have flowed from the region of the Cerberus Fossae graben system [1,2,3] and limited areas forming the eastern plains may have been erupted by low shield volcanoes [4,5]. However, flow of material from west to east is obstructed by a ridge centred on 157°E, 7°N and, prior to this study, vents which might be the source of fluid of a low enough viscosity to form the majority of the flat eastern plains had not been identified. We studied new HiRISE (25cm/px, High Resolution Science Imaging Experiment) images of the ridge between the east and west plains and observed possible source vents for this material: the ridge is cut by a series of pits and fissures which lie at the heads of flows and channels extending towards the surrounding plains. In order to establish the stratigraphic relationships between the vents and plains, this study produced large scale geomorphological maps based on the HiRISE images. The mapping showed that both incised channels and leveed flows extend onto the plain to the south of the ridge and that these were the final phase of plains-forming activity in that region. Conversely, to the north, ridge-sourced deposits only form the plains surface close to the ridge - beyond that, they are overlain by large-scale regional flows that appear to have originated from the direction of Athabasca Valles. In the southeast, a large-scale flow which does not emanate from this ridge forms the plains surface, but there is evidence that the youngest outflow activity from the ridge was contemporaneous with emplacement of this unit. We also performed crater counts to age-date the surfaces and these indicate that plains-forming and ridge-sourced units are of a

  12. Painless Ulcers and Fissures of Toes: Hereditary Sensory Neuropathy, Not Leprosy

    PubMed Central

    Rao, Angoori Gnaneshwar

    2016-01-01

    Hereditary sensory neuropathies (HSN) are rare genetically determined neuropathies. They often manifest as painless injuries in children. We present HSN in a 5-year-old boy who presented with recurrent fissuring and ulceration involving both great toes. PMID:26955138

  13. Painless Ulcers and Fissures of Toes: Hereditary Sensory Neuropathy, Not Leprosy.

    PubMed

    Rao, Angoori Gnaneshwar

    2016-01-01

    Hereditary sensory neuropathies (HSN) are rare genetically determined neuropathies. They often manifest as painless injuries in children. We present HSN in a 5-year-old boy who presented with recurrent fissuring and ulceration involving both great toes.

  14. Microbial validation of vent filters.

    PubMed

    Robertson, J H; Frieben, W R

    1984-08-01

    The Upjohn Company uses filtration to remove microorganisms and particulates from air and other gases which may come in contact with sterile products. To validate the microbial retentivity of these filters, they were challenged with an aerosol of Bacillus subtilis var niger spores. An aerosol challenge was used because it more closely simulated the use for which these filters were designed. The test apparatus was constructed of autoclavable components using a jet-type nebulizer and heated air mixing tube. Characterization of the aerosol particle size distribution with a particle size analyzer demonstrated that 80% of the particles had a diameter of x 3.0 times;m and that the particles had a mean mass diameter of 1.9 times;m with a geometric standard deviation of 1.8 times;m. Studies conducted with aerosols of Bacillus subtilis var niger spores demonstrated that the test apparatus could recover ca. 50% of the spores that were aerosolized. Hydrophobic filters from various manufactures were challenged with an aerosol of at least 10(8) spores of Bacillus subtilis. All filters tested could retain at least 10(9) spores when physical integrity of the filter was verfield.

  15. Putative fissure-resistance QTLs mapped to chromosomes 1 and 8 based on allelic frequency differences observed between fissure-resistant and fissure-susceptible progeny from two segregating populations

    USDA-ARS?s Scientific Manuscript database

    Whole rice kernels have two to three times more market value than broken, which means that any reduction in milling yield results in financial losses for both rice producers and millers. One of the primary causes of rice breakage during milling is fissuring of the rice before it even enters the mil...

  16. Fluoride: Is It Worth to be added in Pit and Fissure Sealants?

    PubMed Central

    Dahake, Prasanna T; Raju, OS; Basappa, N

    2012-01-01

    ABSTRACT Background and objectives: Fluoride is being used for the prevention of dental caries since a long time. Incorporation of fluoride in pit and fissure sealants has been found to reduce initiation and progression of pit and fissure caries. Authors conducted this study to evaluate and compare the effect of fluoride releasing pit and fissure sealants on the inhibition of demineralization of adjacent enamel and to reduce wall lesion frequency. Materials and methods: A total of 60 caries-free human third molars were randomly assigned into three groups receiving conventional resin sealant without fluoride (Group A), fluoride releasing resin sealant (Group B), glass ionomer pit and fissure sealant (Group C). Fissure cavities of 5 × 2 × 1.5 mm were prepared on buccal surfaces of teeth using fissurotomy bur and sealants were applied onto the cavities. The teeth were then thermocycled and exposed to acidified gelatin gel for 6 weeks to induce caries like lesions. A 150 μ m section was taken from each tooth and observed under polarized light microscope to measure the depth of advancing front of outer enamel lesion. The outer lesion depths of all three groups were compared. Results: Enamel demineralization was least in glass ionomer pit and fissure sealant while the demineralization exhibited by nonfluoridated resin and fluoridated resin were comparable. Wall lesion frequency was found to be 0% in all groups. Conclusion and interpretation: The glass ionomer pit and fissure sealant exhibited highest anticariogenic efficacy and hence can be advocated as a means of preventing dental caries. How to cite this article: Prabhakar AR, Dahake PT, Raju OS, Basappa N. Fluoride: Is It Worth to be added in Pit and Fissure Sealants?. Int J Clin Pediatr Dent 2012;5(1):1-5. PMID:25206126

  17. Orientation of the eruption fissures controlled by a shallow magma chamber in Miyakejima

    NASA Astrophysics Data System (ADS)

    Geshi, Nobuo; Oikawa, Teruki

    2016-11-01

    Orientation of the eruption fissures and composition of the lavas of the Miyakejima volcano indicate tectonic influence of a shallow magma chamber on the distribution of eruption fissures. We examined the distributions and magmatic compositions of 23 fissures that formed within the last 2800 years, based on a field survey and a new dataset of 14C ages. The dominant orientation of the eruption fissures in the central portion of the volcano was found to be NE-SW, which is perpendicular to the direction of regional maximum horizontal compressive stress (σHmax). Magmas that show evidences of magma mixing between basaltic and andesitic magmas erupted mainly from the eruption fissures with a higher offset angle from the regional σHmax direction. The presence of a shallow dike-shaped magma chamber controls the distribution of the eruption fissures. The injection of basaltic magma into the shallow andesitic magma chamber caused the temporal rise of internal magmatic pressure in the shallow magma chamber. Dikes extending from the andesitic magma chamber intrude along the local compressive stress field which is generated by the internal excess pressure of the andesitic magma chamber. As the result, the eruption fissures trend parallel to the elongation direction of the shallow magma chamber. Injection of basaltic magma into the shallow andesitic magma chamber caused the magma mixing. Some basaltic dikes from the deep-seated magma chamber reach the ground surface without intersection with the andesitic magma chamber. The patterns of the eruption fissures can be modified in the future as was observed in the case of the destruction of the shallow magma chamber during the 2000 AD eruption.

  18. Fluorine mapping in sound and carious fissures of human teeth using PIGE

    NASA Astrophysics Data System (ADS)

    Yamamoto, H.; Nomachi, M.; Yasuda, K.; Iwami, Y.; Ebisu, S.; Sakai, T.; Fukuda, M.

    2005-04-01

    By using the PIGE technique at JAERI Takasaki, we measured fluorine (F) distribution in a micro area of occlusal fissures in the enamel of human teeth. The fissures were classified into three groups: Group I, no caries; Group II, incipient caries; Group III, advanced caries. The extracted teeth were embedded in epoxy resin and cut along the longitudinal axis through the fissures. The F concentration in the fissure at the cut surface was measured. A 1.7 MeV proton beam accelerated by the TIARA single-ended accelerator was delivered to a micro-beam apparatus. The beam spot size was about 1 μm with a beam current of about 100 pA. A nuclear reaction, 19F (p,αγ)16O, was used to measure the F concentration and gamma-rays from this reaction were detected with a 4″ NaI(Tl) detector. X-rays induced by proton were detected with a Ge detector to measure calcium concentration and the beam intensity was monitored with the X-ray yield from a copper foil for quantitative analysis. The obtained results were shown as two-dimensional mapping. In all specimens, an F concentration was observed around the fissure. The F concentration varied depending on the location of the fissure and decreased towards the inner part of the tooth. The maximum F concentration values in the measured area ranged from 3500-11700 ppm (mean = 6000 ppm) in Group I, 2400-10700 ppm (mean = 6300 ppm) in Group II, and 5200-16900 ppm (mean = 9300 ppm) in Group III. Although high F concentrations tended to be measured in the carious fissures, high values were also recognized in the sound fissures. More studies are necessary to clarify the relationship between F and carious lesions.

  19. Cadherin-mediated cell adhesion is critical for the closing of the mouse optic fissure.

    PubMed

    Chen, Shuyi; Lewis, Brandy; Moran, Andrea; Xie, Ting

    2012-01-01

    Coloboma is a congenital disease that contributes significantly to childhood blindness. It results from the failure in closing the optic fissure, a transient opening on the ventral side of the developing eye. Although human and mouse genetic studies have identified a number of genes associated with coloboma, the detailed cellular mechanisms underlying the optic fissure closure and coloboma formation remain largely undefined. N-cadherin-mediated cell adhesion has been shown to be important for the optic fissure closure in zebrafish, but it remains to be determined experimentally how cell-cell adhesions are involved in the mammalian optic fissure closing process. α-Catenin is required for cell adhesion mediated by all of the classic cadherin molecules, including N-cadherin. In this study, we used the Cre-mediated conditional knockout technique to specifically delete α-catenin from the developing mouse eye to show that it is required for the successful closing of the optic fissure. In α-catenin conditional mutant optic cups, the major cell fates, including the optic fissure margin, neural retina and retinal pigmented epithelium, are specified normally, and the retinal progenitor cells proliferate normally. However, adherens junctions components, including N-cadherin, β-catenin and filamentous actin, fail to accumulate on the apical side of α-catenin mutant retinal progenitor cells, where adherens junctions are normally abundant, and the organization of the neural retina and the optic fissure margin is disrupted. Finally, the α-catenin mutant retina gradually degenerates in the adult mouse eye. Therefore, our results show that α-catenin-mediated cell adhesion and cell organization are important for the fissure closure in mice, and further suggest that genes that regulate cell adhesion may underlie certain coloboma cases in humans.

  20. [Sexual dysfunction is frequent in patients with anal fistulas and anal fissures].

    PubMed

    Broholm, Malene; Møller, Henrik; Gögenur, Ismail

    2015-02-23

    Anal fistulas and fissures are frequent disorders. Affected patients may have significant psychosocial and sexual dysfunction. A few studies have investigated patients with anal fissures and fistulas with regard to sexual dysfunction. These studies showed a significant degree of sexual dysfunction among the affected patients. Data are surprisingly limited in this field. More studies are needed to describe this issue and to define a successful treatment for these patients.

  1. Choroidal fissure acts as an overflow device in cerebrospinal fluid drainage: morphological comparison between idiopathic and secondary normal-pressure hydrocephalus

    PubMed Central

    Yamada, Shigeki; Ishikawa, Masatsune; Iwamuro, Yasushi; Yamamoto, Kazuo

    2016-01-01

    To clarify the pathogenesis of two different types of adult-onset normal-pressure hydrocephalus (NPH), we investigated cerebrospinal fluid distribution on the high-field three-dimensional MRI. The subarachnoid spaces in secondary NPH were smaller than those in the controls, whereas those in idiopathic NPH were of similar size to the controls. In idiopathic NPH, however, the basal cistern and Sylvian fissure were enlarged in concurrence with ventricular enlargement towards the z-direction, but the convexity subarachnoid space was severely diminished. In this article, we provide evidence that the key cause of the disproportionate cerebrospinal fluid distribution in idiopathic NPH is the compensatory direct CSF communication between the inferior horn of the lateral ventricles and the ambient cistern at the choroidal fissure. In contrast, all parts of the subarachnoid spaces were equally and severely decreased in secondary NPH. Blockage of CSF drainage from the subarachnoid spaces could cause the omnidirectional ventricular enlargement in secondary NPH. PMID:27941913

  2. RECURRENT ECTOPIC CRANIOPHARYNGIOMA IN THE SYLVIAN FISSURE THIRTY YEARS AFTER RESECTION THROUGH A PTERIONAL APPROACH: A CASE REPORT AND REVIEW OF THE LITERATURE

    PubMed Central

    CLARK, SHANNON W.; KENNING, TYLER J.; EVANS, JAMES J.

    2015-01-01

    ABSTRACT Local recurrence of craniopharyngiomas after apparently complete resection occurs frequently. Ectopic recurrence remote from the original site has been reported in 18 adult patients. The interval between the original diagnosis and the time of recurrence varies widely in these reports (1–26 years). We report a case of an ectopic recurrence in the sylvian fissure of an adamantinomatous type craniopharyngioma 34 years after the initial presentation and 30 years after the last surgical resection. In addition to this being the latest reported ectopic recurrence, the location of this new lesion in the sylvian fissure is fairly rare, having been reported in only three other cases. We also reviewed the English literature for reports of ectopic recurrent craniopharyngiomas in order to conduct an analysis of surveillance and treatment strategies. PMID:25797995

  3. Mechanical benefits of conservative restoration for dental fissure caries.

    PubMed

    Zhang, Zhongpu; Zheng, Keke; Li, Eric; Li, Wei; Li, Qing; Swain, Michael V

    2016-01-01

    The principle of minimal intervention dentistry (MID) is to limit removal of carious tooth tissue while maximizing its repair and survival potential. The objective of this study is to explore the fracture resistance of a permanent molar tooth with a fissure carious lesion along with three clinical restoration procedures, namely one traditional and two conservative approaches, based upon MID. The traditional restoration employs extensive surgical removal of enamel and dentine about the cavity to eliminate potential risk of further caries development, while conservative method #1 removes significantly less enamel and infected dentine, and conservative method #2 only restores the overhanging enamel above the cavity and leaves the infected and affected dentine as it was. An extended finite element method (XFEM) is adopted here to analyze the fracture behaviors of both two-dimensional (2D) and three-dimensional (3D) modeling of these four different scenarios. It was found that the two conservative methods exhibited better fracture resistance than the traditional restorative method. Although conservative method #2 has less fracture resistance than method #1, it had significantly superior fracture resistance compared to other restorations. More important, after cavity sealing it may potentially enhance the opportunity for remineralization and improved loading bearing capacity and fracture resistance.

  4. Pharmacological Sphincterotomy for Chronic Anal Fissures by Botulinum Toxin A

    PubMed Central

    Wollina, Uwe

    2008-01-01

    Chronic anal fissure is a common proctologic disease. Botulinum toxin (BTX) can be used for temporary chemical denervation to treat this painful disorder. Its application is by intramuscular injections into either the external or internal anal sphincter muscle. The mode of action, application techniques, and possible complications or adverse effects of BTX therapy are discussed in this report. The healing rate is dependent on the BTX dosage. The short-term healing rate (≤ 6 months) is 60–90%, whereas about 50% of the patients show a complete response in long-term follow-up studies (> 1 year). Adverse effects are generally mild, but relapses occur more often than with surgery. Conservative therapy is currently considered as a first-line treatment. With increasing evidence for its efficacy, BTX can now be considered among the first-line nonsurgical treatements. Although, surgical management by lateral sphincterotomy is the most effective treatment, it shows a higher incidence of incontinence and greater general morbidity rate than BTX. BTX is a useful alternative to surgery and in many cases, surgery can be avoided with the use of BTX. PMID:20300345

  5. Pharmacological sphincterotomy for chronic anal fissures by botulinum toxin a.

    PubMed

    Wollina, Uwe

    2008-07-01

    Chronic anal fissure is a common proctologic disease. Botulinum toxin (BTX) can be used for temporary chemical denervation to treat this painful disorder. Its application is by intramuscular injections into either the external or internal anal sphincter muscle. The mode of action, application techniques, and possible complications or adverse effects of BTX therapy are discussed in this report. The healing rate is dependent on the BTX dosage. The short-term healing rate ( 1 year). Adverse effects are generally mild, but relapses occur more often than with surgery. Conservative therapy is currently considered as a first-line treatment. With increasing evidence for its efficacy, BTX can now be considered among the first-line nonsurgical treatements. Although, surgical management by lateral sphincterotomy is the most effective treatment, it shows a higher incidence of incontinence and greater general morbidity rate than BTX. BTX is a useful alternative to surgery and in many cases, surgery can be avoided with the use of BTX.

  6. A study on using texture analysis methods for identifying lobar fissure regions in isotropic CT images.

    PubMed

    Wei, Q; Hu, Y

    2009-01-01

    The major hurdle for segmenting lung lobes in computed tomographic (CT) images is to identify fissure regions, which encase lobar fissures. Accurate identification of these regions is difficult due to the variable shape and appearance of the fissures, along with the low contrast and high noise associated with CT images. This paper studies the effectiveness of two texture analysis methods - the gray level co-occurrence matrix (GLCM) and the gray level run length matrix (GLRLM) - in identifying fissure regions from isotropic CT image stacks. To classify GLCM and GLRLM texture features, we applied a feed-forward back-propagation neural network and achieved the best classification accuracy utilizing 16 quantized levels for computing the GLCM and GLRLM texture features and 64 neurons in the input/hidden layers of the neural network. Tested on isotropic CT image stacks of 24 patients with the pathologic lungs, we obtained accuracies of 86% and 87% for identifying fissure regions using the GLCM and GLRLM methods, respectively. These accuracies compare favorably with surgeons/radiologists' accuracy of 80% for identifying fissure regions in clinical settings. This shows promising potential for segmenting lung lobes using the GLCM and GLRLM methods.

  7. Differential outcome of fissure-positioned tube in closed thoracostomy for primary spontaneous pneumothorax.

    PubMed

    Kim, Yong Won; Byun, Chun Sung; Cha, Yong Sung; Kim, Oh Hyun; Lee, Kang Hyun; Park, Il Hwan

    2015-05-01

    Closed tube thoracostomy is often used to evacuate a primary spontaneous pneumothorax (PSP). Occasionally, this procedure is complicated by placement of the chest tube location in the fissural area instead of pleural space. There is a paucity of studies on outcomes according to chest tube placement. As such, we investigated outcomes of chest tube placement in fissural versus pleural area in closed thoracostomy for PSP. Patients between 14 and 65 years of age who had been treated with chest tube insertion to evacuate PSP were selected based on retrospective review of medical records. Patients selected for this study received chest tube placement at either the fissural or pleural spaces. Those with pre-existing lung disease or those transferred into our hospital after closed thoracostomy were excluded. Of the 255 patients with PSP treated with chest tube insertion, 172 patients were enrolled in this study. Twenty-nine (16.9%) had fissural tube placement and 143 (83.1%) had pleural tube placement. A higher proportion of patients in the fissural versus pleural group required additional chest tube insertion (20.7% vs 4.9%, P = 0.010, respectively). There was no significant difference in body mass index, smoker status, symptom duration, number of episodes, post-thoracostomy complications, need for subsequent management, and duration of hospitalization in either group. In closed thoracostomy for PSP, there is a higher chance of tube dysfunction when the chest tube is positioned at fissural area as compared with the pleural space.

  8. Early results of a rotation flap to treat chronic anal fissures.

    PubMed

    Singh, Meheshinder; Sharma, Abhiram; Duthie, Graeme; Balasingh, Davaraj; Kandasamy, P

    2005-07-01

    Treatment of anal fissures has changed dramatically in the past decade. This is primarily due to a better understanding of its pathophysiology and the implications of the various available options. Only a few anal fissures fail to respond to medical therapy. Sphincterotomy and anal dilatation have fallen out of favour due to the risk of incontinence. Island flaps have been proposed to address this, but 60-70% of the flap donor sites break down with complications. We propose using a rotation flap to overcome this problem. A local rotation flap from perianal skin was used to fill the fissure defect in 14 patients who were followed up for a period of 6 months to determine fissure healing and incidence of donor site breakdown. Twelve patients had complete resolution of their symptoms. Of two patients who developed fissure recurrence, one also had dehiscence of the donor site. There were no donor site complications in the remaining patients. No patient suffered continence defects as a result of the surgery. Rotation flap is a simple, safe and appropriate modality for treating chronic anal fissures. Donor site problems are avoided using this approach. It should be the treatment of choice, particularly in patients who are at risk of incontinence.

  9. Neuromyogenic properties of the internal anal sphincter: therapeutic rationale for anal fissures.

    PubMed

    Bhardwaj, R; Vaizey, C J; Boulos, P B; Hoyle, C H

    2000-06-01

    Lateral sphincterotomy diminishes internal anal sphincter hypertonia and thereby reduces anal canal pressure. This improves anal mucosal blood flow and promotes the healing of anal fissures. However, sphincterotomy can be associated with long term disturbances of sphincter function. The optimal treatment for an anal fissure is to induce a temporary reduction of anal canal resting pressure to allow healing of the fissure without permanently disrupting normal sphincter function. Broader understanding of the intrinsic mechanisms controlling smooth muscle contraction has allowed pharmacological manipulation of anal sphincter tone. We performed an initial Medline literature search to identify all articles concerning "internal anal sphincter" and "anal fissures". This review is based on these articles and on additional publications obtained by manual cross referencing. Internal anal smooth muscle relaxation can be inhibited by stimulation of non-adrenergic non-cholinergic enteric neurones, parasympathetic muscarinic receptors, or sympathetic beta adrenoceptors, and by inhibition of calcium entry into the cell. Sphincter contraction depends on an increase in cytoplasmic calcium and is enhanced by sympathetic adrenergic stimulation. Currently, the most commonly used pharmacological agent in the treatment of anal fissures is topical glyceryl trinitrate, a nitric oxide donor. Alternative agents that exhibit a similar effect via membrane Ca2+ channels, muscarinic receptors, and alpha or beta adrenoceptors are also likely to have a therapeutic potential in treating anal fissures.

  10. Monitoring on Xi'an ground fissures deformation with TerraSAR-X data

    USGS Publications Warehouse

    Zhao, C.; Zhang, Q.; Zhu, W.; Lu, Zhiming

    2012-01-01

    Owing to the fine resolution of TerraSAR-X data provided since 2007, this paper applied 6 TerraSAR data (strip mode) during 3rd Dec. 2009 to 23rd Mar. 2010 to detect and monitor the active fissures over Xi'an region. Three themes have been designed for high precision detection and monitoring of Xi'an-Chang'an fissures, as small baseline subsets (SBAS) to test the atmospheric effects of differential interferograms pair stepwise, 2-pass differential interferogram with very short baseline perpendicular to generate the whole deformation map with 44 days interval, and finally, corner reflector (CR) technique was used to closely monitor the relative deformation time series between two CRs settled crossing two ground fissures. Results showed that TerraSAR data are a good choice for small-scale ground fissures detection and monitoring, while special considerations should be taken for their great temporal and baseline decorrelation. Secondly, ground fissures in Xi'an were mostly detected at the joint section of stable and deformable regions. Lastly, CR-InSAR had potential ability to monitor relative deformation crossing fissures with millimeter precision.

  11. Novel and diverse integron integrase genes and integron-like gene cassettes are prevalent in deep-sea hydrothermal vents.

    PubMed

    Elsaied, Hosam; Stokes, H W; Nakamura, Takamichi; Kitamura, Keiko; Fuse, Hiroyuki; Maruyama, Akihiko

    2007-09-01

    vents, an environment type well removed from anthropogenic disturbance.

  12. Effects of Vent Asymmetry on Steady and Unsteady Eruption Dynamics

    NASA Astrophysics Data System (ADS)

    Sim, S.; Ogden, D.

    2013-12-01

    Models of volcanic eruptions are typically based on symmetric vent and conduit geometries. However, in natural settings, these features are rarely perfectly symmetric. For example, the May 18, 1980 eruption of Mount St Helens (MSH) took place through a highly asymmetrical crater due to the preceding landslide and subsequent vent erosion. In supersonic, high-pressure eruptions, such as what may have occurred at MSH, vent and crater asymmetry can strongly affect the directionality of the eruption. Here we explore flow dynamics resulting from a supersonic, high-pressure eruption though an asymmetric volcanic vent and a symmetric vent using a both unsteady numerical simulations and semi-analytical steady-state models. Preliminary results from both methods suggest that asymmetric vent shape may provide a first-order effect on dynamics of the initial phases of explosive eruptions.

  13. In vitro comparison of the bond strength to the enamel of conventional and self-etching dental fissure sealants.

    PubMed

    Stellini, E; De Francesco, M; Avventi, M; Gracco, A; Berengo, M; Simionato, F; Mazzoleni, S

    2013-12-01

    Dental caries in pits and fissures of molars is still very common in young people, despite a gradual reduction in their incidence and prevalence. Prevention with the aid of dental fissure sealants can help to reduce the onset of decay. In vitro tests were conducted to compare the bond strength to enamel of self-etching sealants versus those applied using the conventional procedure. The lingual surface of 40 extracted, caries-free, mandibular third molars was milled to make them flat. The prepared teeth were randomly divided into two groups of 20 teeth each: those in Group A were treated with Clinpro (3M ESPE, St. Paul, MN, USA); those in Group B with Quick Seal (BJM Laboratories Ltd, Or-Yehuda, Israel). Cylinders of sealant were attached to the enamel of the flat surfaces of the samples using a polymerisation process treating the surfaces involved according to the type of material. All samples underwent load testing by means of a universal test machine. The results of the load testing, measured in MPa, were analysed using the Student's t-test for independent samples and the differences proved significant, indicating that the traditionally- applied sealant (mean strength 21.06 MPa) assured a significantly stronger bond (p <.05) than the self-etching sealant (mean strength 10.43 MPa) under our experimental conditions. CONCLUSION Conventional sealants generally provide a considerably higher bond strength than self-etching sealants.

  14. A 3-dimensional numerical simulation of the atmospheric injection of aerosols by a hypothetical basaltic fissure eruption

    NASA Technical Reports Server (NTRS)

    Tripoli, Gregory J.; Thompson, Starley L.

    1988-01-01

    Researchers simulated the atmospheric response to a hypothetical basaltic fissure eruption using heating rates based on the Roza flow eruption. The simulation employs the Colorado State University Regional Atmospheric Model (RAMS) with scavenging effects. The numerical model is a three-dimensional non-hydrostatic time-split compressible cloud/mesoscale model. Explicit microphysics include prediction of cloud, rain, crystal, and hail precipitation types. Nucleation and phoretic scavenging are predicted assuming that the pollutant makes an effective cloud droplet nucleus. Smoke is carried as a passive tracer. Long and short wave radiation heating tendencies, including the effects of the smoke, are parameterized. The longwave emission by the lava surface is neglected in the parameterization and included as an explicit heating term instead. A regional scale domain of 100 x 100 km in the horizontal and 22 km high is used. The horizontal grid spacing is taken to be 2 km and the vertical spacing is taken to be 0.75 km. The initial atmospheric state is taken to be horizontally homogenous and based on the standard atmospheric sounding. The fissure is assumed to be 90 km long and oriented in a zig/zag pattern.

  15. The biological deep sea hydrothermal vent as a model to study carbon dioxide capturing enzymes.

    PubMed

    Minic, Zoran; Thongbam, Premila D

    2011-01-01

    Deep sea hydrothermal vents are located along the mid-ocean ridge system, near volcanically active areas, where tectonic plates are moving away from each other. Sea water penetrates the fissures of the volcanic bed and is heated by magma. This heated sea water rises to the surface dissolving large amounts of minerals which provide a source of energy and nutrients to chemoautotrophic organisms. Although this environment is characterized by extreme conditions (high temperature, high pressure, chemical toxicity, acidic pH and absence of photosynthesis) a diversity of microorganisms and many animal species are specially adapted to this hostile environment. These organisms have developed a very efficient metabolism for the assimilation of inorganic CO₂ from the external environment. In order to develop technology for the capture of carbon dioxide to reduce greenhouse gases in the atmosphere, enzymes involved in CO₂ fixation and assimilation might be very useful. This review describes some current research concerning CO₂ fixation and assimilation in the deep sea environment and possible biotechnological application of enzymes for carbon dioxide capture.

  16. The Biological Deep Sea Hydrothermal Vent as a Model to Study Carbon Dioxide Capturing Enzymes

    PubMed Central

    Minic, Zoran; Thongbam, Premila D.

    2011-01-01

    Deep sea hydrothermal vents are located along the mid-ocean ridge system, near volcanically active areas, where tectonic plates are moving away from each other. Sea water penetrates the fissures of the volcanic bed and is heated by magma. This heated sea water rises to the surface dissolving large amounts of minerals which provide a source of energy and nutrients to chemoautotrophic organisms. Although this environment is characterized by extreme conditions (high temperature, high pressure, chemical toxicity, acidic pH and absence of photosynthesis) a diversity of microorganisms and many animal species are specially adapted to this hostile environment. These organisms have developed a very efficient metabolism for the assimilation of inorganic CO2 from the external environment. In order to develop technology for the capture of carbon dioxide to reduce greenhouse gases in the atmosphere, enzymes involved in CO2 fixation and assimilation might be very useful. This review describes some current research concerning CO2 fixation and assimilation in the deep sea environment and possible biotechnological application of enzymes for carbon dioxide capture. PMID:21673885

  17. Hydrothermal Vents in an Unusual Geotectonic Setting: the Kairei and Edmond Vent Fields, Central Indian Ridge

    NASA Astrophysics Data System (ADS)

    Humphris, S. E.; Fornari, D. J.

    2001-12-01

    Over the past 25 years, field investigations along the global mid-ocean ridge (MOR) system have indicated that hydrothermal activity occurs in a range of geotectonic settings and is characterized by different styles of venting and mineralization. In March-May 2001, we conducted multidisciplinary investigations of two hydrothermally active areas on the Central Indian Ridge -- an intermediate-rate spreading system ( ~50-60 mm/yr). The Kairei vent field (about 25° 20'S) is located in the first segment north of the Rodriguez Triple Junction (RTJ) and was discovered by Japanese scientists in August 2000. The Edmond vent field (about 23° 53'S) is located two segments north of Kairei. Both vent fields occur at the northern ends of segments with very straight rift valley walls, in the vicinity of rounder plan-view basins at non-transform discontinuities. The Kairei vent field is located on a bench high on the stair-step eastern rift valley wall, nearly 7 km from the ridge axis, and at a depth range (2415-2460 m) ~1800 m shallower than the rift valley floor. Similarly, the Edmond vent field is located high on the eastern rift valley wall about 6 km from the adjacent rift axis at a depth range of 3290-3320 m. It is constructed on a small protrusion that extends south from the eastern rift wall and that forms the northeast corner of a ~60 m deep basin. The Kairei and Edmond vent fields are built on seafloor with a slope typically of 10-45° . High temperature venting at both sites is focused along a NW-SE trend (typically 100-120 m long and 80-90 m wide) and is likely fault-controlled. Both fields also include peripheral relict sulfide chimneys, old disaggregated sulfide structures, and massive sulfide talus, indicating that hydrothermal activity has been focused at these sites over long periods of time. Edmond is distinct from Kairei in its abundance of orange-brown, Fe-oxyhydroxide sediments that are several cm thick in depressions, and coat sulfide structures and talus

  18. 46 CFR 153.353 - High velocity vents.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false High velocity vents. 153.353 Section 153.353 Shipping... Systems § 153.353 High velocity vents. The discharge point of a B/3 or 4m venting system must be located..., unimpeded jet; (b) The jet has a minimum exit velocity of 30 m/sec (approx. 98.4 ft/sec); and (c) The...

  19. 46 CFR 153.353 - High velocity vents.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false High velocity vents. 153.353 Section 153.353 Shipping... Systems § 153.353 High velocity vents. The discharge point of a B/3 or 4m venting system must be located..., unimpeded jet; (b) The jet has a minimum exit velocity of 30 m/sec (approx. 98.4 ft/sec); and (c) The...

  20. 46 CFR 153.353 - High velocity vents.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false High velocity vents. 153.353 Section 153.353 Shipping... Systems § 153.353 High velocity vents. The discharge point of a B/3 or 4m venting system must be located..., unimpeded jet; (b) The jet has a minimum exit velocity of 30 m/sec (approx. 98.4 ft/sec); and (c) The...

  1. 46 CFR 153.353 - High velocity vents.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false High velocity vents. 153.353 Section 153.353 Shipping... Systems § 153.353 High velocity vents. The discharge point of a B/3 or 4m venting system must be located..., unimpeded jet; (b) The jet has a minimum exit velocity of 30 m/sec (approx. 98.4 ft/sec); and (c) The...

  2. 46 CFR 153.353 - High velocity vents.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false High velocity vents. 153.353 Section 153.353 Shipping... Systems § 153.353 High velocity vents. The discharge point of a B/3 or 4m venting system must be located..., unimpeded jet; (b) The jet has a minimum exit velocity of 30 m/sec (approx. 98.4 ft/sec); and (c) The...

  3. Flashback flame arrester devices for fuel cargo tank vapor vents

    NASA Astrophysics Data System (ADS)

    Bjorklund, R. A.; Kushida, R. O.

    1981-03-01

    The flame quenching capability of four types of flame arresting devices suitable for installation on fuel cargo tank vents of marine transport vessels is evaluated. A single 30 mesh screen, a dual 20 mesh screen, a spiral wound crimped metal ribbon, and a packed bed of ballast rings were tested. Flame speed and flame penetration of the test arresters were determined. Eight fuels representative of bulk cargoes were tested. The test arresters quenched a minimum of three flashback flames from all eight fuels, with one exception: high speed ethylene flames penetrated the dual 20 mesh screen on three tests. The arresters withstood the sustained flame from a propane/air mixture for 30 minutes. None of the arresters withstood the sustained flame from an ethylene/air mixture for more than 7 minutes.

  4. Flashback flame arrester devices for fuel cargo tank vapor vents

    NASA Technical Reports Server (NTRS)

    Bjorklund, R. A.; Kushida, R. O.

    1981-01-01

    The flame quenching capability of four types of flame arresting devices suitable for installation on fuel cargo tank vents of marine transport vessels is evaluated. A single 30 mesh screen, a dual 20 mesh screen, a spiral wound crimped metal ribbon, and a packed bed of ballast rings were tested. Flame speed and flame penetration of the test arresters were determined. Eight fuels representative of bulk cargoes were tested. The test arresters quenched a minimum of three flashback flames from all eight fuels, with one exception: high speed ethylene flames penetrated the dual 20 mesh screen on three tests. The arresters withstood the sustained flame from a propane/air mixture for 30 minutes. None of the arresters withstood the sustained flame from an ethylene/air mixture for more than 7 minutes.

  5. Multiscale Strain as a Predictor of Impact-Induced Fissuring in Articular Cartilage.

    PubMed

    Henak, Corinne R; Bartell, Lena R; Cohen, Itai; Bonassar, Lawrence J

    2017-03-01

    Mechanical damage is central to both initiation and progression of osteoarthritis (OA). However, specific causal links between mechanics and cartilage damage are incompletely understood, which results in an inability to predict failure. The lack of understanding is primarily due to the difficulty in simultaneously resolving the high rates and small length scales relevant to the problem and in correlating such measurements to the resulting fissures. This study leveraged microscopy and high-speed imaging to resolve mechanics on the previously unexamined time and length scales of interest in cartilage damage, and used those mechanics to develop predictive models. The specific objectives of this study were to: first, quantify bulk and local mechanics during impact-induced fissuring; second, develop predictive models of fissuring based on bulk mechanics and local strain; and third, evaluate the accuracy of these models in predicting fissures. To achieve these three objectives, bovine tibial cartilage was impacted using a custom spring-loaded device mounted on an inverted microscope. The occurrence of fissures was modulated by varying impact energy. For the first objective, during impact, deformation was captured at 10,000 frames per second and bulk and local mechanics were analyzed. For the second objective, data from samples impacted with a 1.2 mm diameter rod were fit to logistic regression functions, creating models of fissure probability based on bulk and local mechanics. Finally, for the third objective, data from samples impacted with a 0.8 mm diameter rod were used to test the accuracy of model predictions. This study provides a direct comparison between bulk and local mechanical thresholds for the prediction of fissures in cartilage samples, and demonstrates that local mechanics provide more accurate predictions of local failure than bulk mechanics provide. Bulk mechanics were accurate predictors of fissure for the entire sample cohort, but poor predictors

  6. 49 CFR 192.187 - Vaults: Sealing, venting, and ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY... Components § 192.187 Vaults: Sealing, venting, and ventilation. Each underground vault or closed top pit...

  7. 33. BUILDING 1006, TYPICAL CEILING VENT REGISTER. Presidio of ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    33. BUILDING 1006, TYPICAL CEILING VENT REGISTER. - Presidio of San Francisco, Letterman General Hospital, Building No. 27, Letterman Hospital Complex, Edie Road, San Francisco, San Francisco County, CA

  8. Scientists as stakeholders in conservation of hydrothermal vents.

    PubMed

    Godet, Laurent; Zelnio, Kevin A; VAN Dover, Cindy L

    2011-04-01

    Hydrothermal vents are deep-sea ecosystems that are almost exclusively known and explored by scientists rather than the general public. Continuing scientific discoveries arising from study of hydrothermal vents are concommitant with the increased number of scientific cruises visiting and sampling vent ecosystems. Through a bibliometric analysis, we assessed the scientific value of hydrothermal vents relative to two of the most well-studied marine ecosystems, coral reefs and seagrass beds. Scientific literature on hydrothermal vents is abundant, of high impact, international, and interdisciplinary and is comparable in these regards with literature on coral reefs and seagrass beds. Scientists may affect hydrothermal vents because their activities are intense and spatially and temporally concentrated in these small systems. The potential for undesirable effects from scientific enterprise motivated the creation of a code of conduct for environmentally and scientifically benign use of hydrothermal vents for research. We surveyed scientists worldwide engaged in deep-sea research and found that scientists were aware of the code of conduct and thought it was relevant to conservation, but they did not feel informed or confident about the respect other researchers have for the code. Although this code may serve as a reminder of scientists' environmental responsibilities, conservation of particular vents (e.g., closures to human activity, specific human management) may effectively ensure sustainable use of vent ecosystems for all stakeholders.

  9. [Clinical evaluation of fluor protector and glass-ionomer cement used as pit and fissure sealant for preventing pit and fissure caries in children].

    PubMed

    Ji, Pei-hong; Xu, Quan-lin; Ba, Yong

    2007-08-01

    To study the clinical effect of the fluor protector and glass-ionomer cement used as pit and fissure sealant for preventing pit and fissure caries in children. 622 health permanent teeth in 6-8 years old children were divided into three groups. Children in the experimental group A (n=207,335 teeth) underwent fluor protector every six months, experimental group B(n=205, 327 teeth) with glass-ionomer cement used as pit and fissure sealant and children in the control group(n=210, 354 teeth) underwent no treatment. The incidence of caries were compared among the three groups using SPSS10.0 software package after 3 years. After 3 years, the incidence of caries in A and B experimental groups were lower than in the control group, the difference was significant (P<0.01), but there were no significant difference between group A and group B (P>0.05). Fluor protector and glass-ionomer cement used as pit and fissure sealant also have good clinical effect in preventing caries.

  10. Source analysis of interictal spikes in polymicrogyria: loss of relevant cortical fissures requires simultaneous EEG to avoid MEG misinterpretation.

    PubMed

    Bast, Thomas; Ramantani, Georgia; Boppel, Tobias; Metzke, Tanja; Ozkan, Ozdin; Stippich, Christoph; Seitz, Angelika; Rupp, Andre; Rating, Dietz; Scherg, Michael

    2005-05-01

    Multiple source analysis of interictal EEG and MEG spikes was used to identify irritative zones in polymicrogyria (PMG). Spike onset times and source localization were compared between both modalities. PMG is characterized by a marked loss of deep cortical fissures. Hence, differences between EEG and MEG were expected since MEG signals are predominantly generated from tangentially orientated neurons in fissures. We studied 7 children and young adults (age 7.5 to 19 years) with localization-related epilepsy and unilateral polymicrogyria (PMG) as defined from anatomical MRI. 122-channel whole-head MEG and 32-channel EEG were recorded simultaneously for 25 to 40 min. Using the BESA program, interictal spikes were identified visually and used as templates to search for similar spatio-temporal spike patterns throughout the recording. Detected similar spikes (r > 0.85) were averaged, high-pass filtered (5 Hz) to enhance spike onset, and subjected to multiple spatio-temporal source analysis. Source localization was visualized by superposition on T1-weighted MRI and compared to the lesion. Nine spike types were identified in seven patients (2 types in 2 patients). Eight out of nine EEG sources and seven MEG sources modeling spike onset were localized within the visible lesion. EEG spike onset preceded MEG significantly in two spike types by 19 and 25 ms. This was related to radial onset activity in EEG while MEG localized propagated activity. In one case, the earliest MEG spike activity was localized to the normal hemisphere while the preceding radial EEG onset activity was localized within the lesion. Distances between EEG and MEG onset sources varied markedly between 9 and 51 mm in the eight spike types with concordant lateralization. Interictal irritative zones were localized within the lesion in PMG comparable to other malformations, e.g., FCD. Discrepancies in MEG and EEG were related to the lack of deep fissures in PMG. In two cases, MEG was blind to the onset of

  11. Retention and effectiveness of fissure sealants in Kuwaiti school children.

    PubMed

    Francis, R; Mascarenhas, A K; Soparkar, P; Al-Mutawaa, S

    2008-12-01

    To evaluate the retention and effectiveness of fissure sealants in permanent first molars in a public programme. Sealant retention in permanent first molars was evaluated in 452 children aged 6-8 years in 20 primary schools under the care of the School Oral Health Programme, Kuwait-Forsyth. The sealants were placed using rubber dam or cotton roll isolation, after cleaning with pumice and rubber cup, and 15 seconds etching. Sealant retention was evaluated at one and two years and scored as complete, partial or complete loss of sealant. Caries was scored when sealant was partially or completely lost. A total of 2,744 sealants were applied, with 2,324 and 2,288 sealants examined at the end of the first and second year respectively. In two years, 75% of the sealants were completely retained, 2.9% partially lost, 7.3% completely lost, and 14.8% resealed or restored. A small proportion of teeth (0.9%) were carious. Multivariate analyses showed that occlusal surfaces were 2.8 times more likely to retain a sealant than the buccal and palatal pits (95% CI 2.7-3.9, p<0.0001), and maxillary teeth were 1.3 times more likely to retain their sealant than the mandibular teeth (95% CI 1.01-1.5, p=0.04). Maxillary teeth were less likely to be carious (OR=0.6, 95% CI 0.4-0.97), p=0.03) and occlusal surfaces were 2.8 times more likely to be carious (95% CI 1.9-4.3), p<0.0001). No differences in sealant retention (p=0.24) and caries (p=0.19) were seen between teeth isolated using rubberdam or cotton roll. Sealant retention was high, and sealants were effective in preventing caries.

  12. Plaque and saliva fluoride levels after placement of fluoride releasing pit and fissure sealants.

    PubMed

    Rajtboriraks, Daranee; Nakornchai, Siriruk; Bunditsing, Panit; Surarit, Rudee; Iemjarern, Piyarat

    2004-01-01

    The objectives of this study were to investigate the fluoride levels in plaque and saliva before and after applying fluoride-containing pit and fissure sealants, and compare the fluoride release of 2 types of sealants at the different time intervals. Eighteen children ages 6 to 9 years were randomly divided into 2 groups: Group 1--sealant containing fluorosilicate glass (Helioseal-F); and group 2--sealant containing methacryloyl fluoride-methyl methacrylate copolymer (Teethmate-F). Saliva and plaque samples were collected before and after the sealants were placed on their 4 first permanent molars. Fluoride levels were determined using the microdiffusion method. Fluoride concentrations before and after placing the sealants were analyzed by paired t test, and the fluoride concentrations between the 2 sealants were compared by t test, with the level of significance at 0.05. There was no significant difference between salivary fluoride levels before and after sealant placement application in both groups. The plaque fluoride level of Helioseal-F group at 24 hours was significantly higher than the baseline level (P = .03), and was not different afterwards. The plaque fluoride levels after sealant with Teethmate-F were not significantly different when compared to the baseline. However, there were no significant differences between salivary and plaque fluoride levels of the 2 groups at different time intervals. The groups sealed with sealant containing fluorosilicate glass showed significant increase of plaque fluoride level only at 24 hours after sealant placement.

  13. In vitro study of microleakage of different techniques of surface preparation used in pits and fissures.

    PubMed

    Javadinejad, Shahrzad; Nejad, Shahrzad Javadi; Razavi, Mohamad; Birang, Reza; Atefat, Mohamad

    2012-01-01

    The purpose of this in vitro study was to evaluate the effect of different techniques of surface preparation on the microleakage of a sealant applied with traditional acid etching and self-etched bonding agent. A total of 60 extracted third molars were randomly assigned into six groups (n = 10/each). The occlusal surfaces were sealed with a sealant (Clinpro) after one of the following pretreatments: (1) phosphoric acid etching; (2) Prompt L-Pop; (3) laser + etching; (4) laser + Prompt L-Pop; (5) air abrasion + etching; (6) air abrasion + Prompt L-Pop. The specimens were immersed in a 0.5% basic fuchsin solution. Buccolingual cuts parallel to the long axis of the tooth were made. The surfaces were scored 0--2 for extent of microleakage using a microscope and the data were analyzed statistically. The poorest results were obtained with laser + Prompt L-Pop which showed a greater number of specimens with microleakage (80%). Air abrasion surface preparation + phosphoric acid etching showed less microleakage than the other groups (40%). Kruskal--Wallis and t-tests revealed no significant difference in microleakage between six groups. conclusion: The self-etching adhesive studied seems an attractive alternative to the acid-etch technique for sealant application in young children where simplifications in the clinical procedure are warranted. No significant difference was noted between the different types of enamel preparation before fissure sealant.

  14. Retention of resin-based filled and unfilled pit and fissure sealants: A comparative clinical study.

    PubMed

    Reddy, V Rajashekar; Chowdhary, Nagalakshmi; Mukunda, K S; Kiran, N K; Kavyarani, B S; Pradeep, M C

    2015-03-01

    The most caries-susceptible period of a permanent first molar tooth is the eruption phase, during which the enamel is not fully matured and it is usually difficult for the child to clean the erupting tooth surfaces. Sealing occlusal pits and fissures with resin-based pit and fissure sealants is a proven method to prevent occlusal caries. The difference in the viscosity of the sealants differs in the penetration into pit and fissures and abrasive wear resistance property due to the addition of filler particles. The present study was conducted to evaluate and compare the retention of the resin-based filled (Helioseal F, Ivoclar Vivadent) and unfilled (Clinpro, 3M ESPE) pit and fissure sealants, which is important for their effectiveness. Fifty-six children between the age group of 6 and 9 years, with all four newly erupted permanent first molars were selected. Sealants were applied randomly using split mouth design technique on permanent first molars. Evaluation of sealant retention was performed at regular intervals over 12 months, using Simonsen's criteria at 2(nd), 4(th), 6(th), 8(th), 10(th) and 12(th) month. The results were subjected to statistical analysis. At the end of our study period (12(th) month), 53.57% showed complete retention, 37.50% showed partial retention, and 8.83% showed complete missing of resin-based filled (Helioseal F) pit and fissure sealant. And, 64.29% showed complete retention, 32.14% showed partial retention, and 3.57% showed complete missing of resin-based unfilled (Clinpro) pit and fissure sealant. This difference in retention rates between filled and unfilled pit and fissure sealants was not statistically significant. The difference in retention rates between Helioseal F and Clinpro was not statistically significant, but Clinpro (unfilled) sealant showed slightly higher retention rates and clinically better performance than Helioseal F (filled).

  15. Comparison of various concentrations of tricalcium phosphate nanoparticles on mechanical properties and remineralization of fissure sealants.

    PubMed

    Tavassoli-Hojjati, Sara; Atai, Mohammad; Haghgoo, Roza; Rahimian-Imam, Sara; Kameli, Somayeh; Ahmaian-Babaki, Fatemeh; Hamzeh, Faezeh; Ahmadyar, Maryam

    2014-07-01

    The aim of this study was to investigate the mechanical properties (flexural strength, micro-shear bond strength) and remineralizing potential of fissure sealants by adding various concentrations of β-tricalcium phosphate nanoparticles. This in-vitro study consisted of five experimental groups containing prepared nano-fisssure sealants (1-5 wt.% β-TCP nanoparticles) and two control groups containing a prepared and a commercial fissure sealant. Flexural/micro-shear bond strength values were measured using Zwick test machine. Cavities on sixty healthy premolar teeth were filled with the fissure sealants containing 0-5 wt.% of nano β-TCP. The samples were assessed for remineralization under scanning electron microscopy (SEM) and EDAX. Kolmogorov-Smirnov test, One-way ANOVA and Tukey's Post Hoc analysis/HSD were used to analyze the data. There was no significant difference between the flexural strengths/elastic modulus of the 0-5 wt.% nano β-TCP groups (p>0.05). The average flexural strength/elastic modulus of the prepared fissure sealant group (0%) was significantly higher than the commercial fissure sealant group (Clinpro) (p<0.05). There was no significant difference between micro-shear bond strengths of the experimental groups (1-5 wt.%), and between the commercial and the prepared (0%) fissure sealant groups (p>0.05). Examining the samples under SEM showed a significant increase in thickness of the intermediate layer with increasing concentrations of β-TCP nanoparticles (p<0.05). Addition of 1-5 wt.% β-TCP nanoparticles to the fissure sealants significantly increased the remineralization potential without affecting the mechanical properties.

  16. Retention of resin-based filled and unfilled pit and fissure sealants: A comparative clinical study

    PubMed Central

    Reddy, V. Rajashekar; Chowdhary, Nagalakshmi; Mukunda, K. S.; Kiran, N. K.; Kavyarani, B. S.; Pradeep, M. C.

    2015-01-01

    Background and Objectives: The most caries-susceptible period of a permanent first molar tooth is the eruption phase, during which the enamel is not fully matured and it is usually difficult for the child to clean the erupting tooth surfaces. Sealing occlusal pits and fissures with resin-based pit and fissure sealants is a proven method to prevent occlusal caries. The difference in the viscosity of the sealants differs in the penetration into pit and fissures and abrasive wear resistance property due to the addition of filler particles. The present study was conducted to evaluate and compare the retention of the resin-based filled (Helioseal F, Ivoclar Vivadent) and unfilled (Clinpro, 3M ESPE) pit and fissure sealants, which is important for their effectiveness. Materials and Methods: Fifty-six children between the age group of 6 and 9 years, with all four newly erupted permanent first molars were selected. Sealants were applied randomly using split mouth design technique on permanent first molars. Evaluation of sealant retention was performed at regular intervals over 12 months, using Simonsen's criteria at 2nd, 4th, 6th, 8th, 10th and 12th month. The results were subjected to statistical analysis. Results: At the end of our study period (12th month), 53.57% showed complete retention, 37.50% showed partial retention, and 8.83% showed complete missing of resin-based filled (Helioseal F) pit and fissure sealant. And, 64.29% showed complete retention, 32.14% showed partial retention, and 3.57% showed complete missing of resin-based unfilled (Clinpro) pit and fissure sealant. This difference in retention rates between filled and unfilled pit and fissure sealants was not statistically significant. Conclusion: The difference in retention rates between Helioseal F and Clinpro was not statistically significant, but Clinpro (unfilled) sealant showed slightly higher retention rates and clinically better performance than Helioseal F (filled). PMID:25821368

  17. Adhesive systems under fissure sealants: yes or no?: A systematic review and meta-analysis.

    PubMed

    Bagherian, Ali; Sarraf Shirazi, Alireza; Sadeghi, Ramin

    2016-06-01

    The authors of this systematic review and meta-analysis had 2 aims: to evaluate fissure sealant retention with and without the use of an adhesive system and to compare fissure sealant retention using etch-and-rinse adhesive systems versus self-etching adhesive systems. The authors conducted a literature search (all articles published through November 1, 2015) to identify studies for inclusion in this systematic review. They assessed the quality of the evidence provided using the modified Jadad scale and performed meta-analyses using a random-effects model. The authors considered 12 studies that met the inclusion criteria for the systematic review. In addition, they used 5 of 9 studies related to the first part of the study and 3 of 4 studies related to the second part of the study that met the inclusion criteria for meta-analysis. In the analysis of the first part of the systematic review, the authors found that adhesive systems had a significant positive effect on fissure sealant (odds ratio, 3.294; 95% confidence interval, 1.292-8.401; P = .013). In the analysis of the second part of the systematic review, the authors found that etch-and-rinse adhesives were superior to self-etching adhesives in the fissure sealant procedure (odds ratio, 14.569; 95% confidence interval, 2.616-81.131; P = .002). The use of adhesive systems beneath fissure sealants can increase the retention of fissure sealants. Also, when adhesive systems are used with fissure sealants, etch-and-rinse systems are preferable. Copyright © 2016 American Dental Association. Published by Elsevier Inc. All rights reserved.

  18. Comparison of Various Concentrations of Tricalcium Phosphate Nanoparticles on Mechanical Properties and Remineralization of Fissure Sealants

    PubMed Central

    Tavassoli-Hojjati, Sara; Atai, Mohammad; Haghgoo, Roza; Rahimian-Imam, Sara; Kameli, Somayeh; Ahmaian-Babaki, Fatemeh; Hamzeh, Faezeh; Ahmadyar, Maryam

    2014-01-01

    Objective: The aim of this study was to investigate the mechanical properties (flexural strength, micro-shear bond strength) and remineralizing potential of fissure sealants by adding various concentrations of β-tricalcium phosphate nanoparticles. Materials and Methods: This in-vitro study consisted of five experimental groups containing prepared nano-fisssure sealants (1–5 wt.% β-TCP nanoparticles) and two control groups containing a prepared and a commercial fissure sealant. Flexural/micro-shear bond strength values were measured using Zwick test machine. Cavities on sixty healthy premolar teeth were filled with the fissure sealants containing 0–5 wt.% of nano β-TCP. The samples were assessed for remineralization under scanning electron microscopy (SEM) and EDAX. Kolmogorov-Smirnov test, One-way ANOVA and Tukey’s Post Hoc analysis/HSD were used to analyze the data. Results: There was no significant difference between the flexural strengths/elastic modulus of the 0–5 wt.% nano β-TCP groups (p>0.05). The average flexural strength/elastic modulus of the prepared fissure sealant group (0%) was significantly higher than the commercial fissure sealant group (Clinpro) (p<0.05). There was no significant difference between micro-shear bond strengths of the experimental groups (1–5 wt.%), and between the commercial and the prepared (0%) fissure sealant groups (p>0.05). Examining the samples under SEM showed a significant increase in thickness of the intermediate layer with increasing concentrations of β-TCP nanoparticles (p<0.05). Conclusion: Addition of 1–5 wt.% β-TCP nanoparticles to the fissure sealants significantly increased the remineralization potential without affecting the mechanical properties. PMID:25584048

  19. Haemorrhoids and anal fissures during pregnancy and after childbirth: a prospective cohort study.

    PubMed

    Poskus, T; Buzinskienė, D; Drasutiene, G; Samalavicius, N E; Barkus, A; Barisauskiene, A; Tutkuviene, J; Sakalauskaite, I; Drasutis, J; Jasulaitis, A; Jakaitiene, A

    2014-12-01

    To identify the incidence and risk factors of haemorrhoids and fissures during pregnancy and after childbirth. Prospective observational cohort study. University hospital and outpatient clinics in Lithuania. A total of 280 pregnant women followed up until 1 month after delivery. Women were examined four times through pregnancy and after delivery; those that developed peri-anal diseases were compared with those that did not. Incidence, time and risk factors of haemorrhoids and fissures. In all, 123 (43.9%) women developed peri-anal disease: 1.6% in the first trimester, 61% during the third trimester, 34.1% after delivery and 3.3% 1 month after delivery; 114 (40.7%) women were diagnosed with haemorrhoids, seven (2.5%) with haemorrhoids and anal fissure and two (0.71%) with anal fissure. Ninety-nine (80.5%) women had vaginal delivery and 24 (19.5%) women had undergone caesarean section. Multivariate analysis identified personal history of peri-anal diseases (odds ratio [OR] 11.93; 95% confidence interval [95% CI] 2.18-65.30), constipation (OR 18.98; 95% CI 7.13-50.54), straining during delivery for more than 20 minutes (OR 29.75; 95% CI 4.00-221.23) and birthweight of newborn>3800 g (OR 17.99; 95% CI 3.29-98.49) as significant predictors of haemorrhoids and anal fissures during pregnancy and perinatal period. Haemorrhoids and fissures are common during the last trimester of pregnancy and 1 month after delivery, with constipation, personal history of haemorrhoids or fissures, birthweight of newborn>3800 g, straining during delivery for more than 20 minutes being independently associated risk factors. © 2014 Royal College of Obstetricians and Gynaecologists.

  20. Diltiazem heals glyceryl trinitrate-resistant chronic anal fissures: a prospective study.

    PubMed

    Jonas, Marion; Speake, William; Scholefield, John H

    2002-08-01

    Both topical diltiazem, a calcium channel blocker, and glyceryl trinitrate, a nitric oxide donor, lower anal pressure and heal two-thirds of chronic anal fissures. This study evaluated the efficacy of diltiazem for fissures that failed to heal with glyceryl trinitrate. Consecutive patients with persistent chronic fissures despite treatment with 0.2 percent glyceryl trinitrate ointment underwent anal manometry before and for 1 hour after application of 700 mg of 2 percent diltiazem gel to the distal anal canal. Patients applied diltiazem twice daily for eight weeks or until the fissure had healed. At fortnightly review, fissure healing was assessed, and side effects were noted. Patients scored symptoms of pain, bleeding, and irritation using linear visual analog scales at the initial and follow-up visits. In 39 patients (13 males; median age, 42 (range, 20- 80) years), topical 2 percent diltiazem gel lowered anal resting pressure by 20 percent from a median of 93 to 74 cm H2O (P < 0.0001, Wilcoxon), and fissures healed in 19 (49 percent) within 8 weeks. Before diltiazem, 27 patients (69 percent) had used a complete course of glyceryl trinitrate (0.5 g twice daily for 8 weeks), and 12 (44 percent) of these healed with diltiazem. The remaining 12 patients had discontinued glyceryl trinitrate prematurely or used less because of headaches; 7 (58 percent) of these healed with diltiazem, and 5 (42 percent) did not. Side effects occurred in four patients (10 percent): three reported perianal itching but continued with treatment, and one developed headaches, drowsiness, and mood swings six weeks into treatment and stopped diltiazem at that time. Topical 2 percent diltiazem is effective treatment for glyceryl trinitrate-resistant chronic anal fissures. Side effects, mainly perianal itching, may occur in 10 percent of patients but are generally tolerated.

  1. Effectiveness of higher doses of botulinum toxin to induce healing in patients with chronic anal fissures.

    PubMed

    Brisinda, Giuseppe; Maria, Giorgio; Sganga, Gabriele; Bentivoglio, Anna Rita; Albanese, Alberto; Castagneto, Marco

    2002-02-01

    Botulinum toxin induces healing in patients with idiopathic anal fissures. One hundred-fifty patients with posterior anal fissures were treated with botulinum toxin injected in the internal anal sphincter on each side of the anterior midline. Subjects were randomized into 2 treatment groups based on the number of units of botulinum toxin injected. Patients in group I were treated with 20 units of botulinum toxin and, if the fissure persisted, were retreated with 30 units. Patients in group II were treated with 30 units and retreated with 50 units, if the fissure persisted. The 2 groups were comparable in age, gender distribution, duration of symptoms, resting pressure, and maximum voluntary pressure at anorectal manometry. One month after the injection, examinations revealed complete healing in 55 patients (73%) from group I and 65 patients (87%) from group II (P =.04). Five patients from group II reported a mild incontinence of flatus that lasted 2 weeks after the treatment and disappeared spontaneously. The values of the resting anal pressure (P=.3) and the maximum voluntary pressure (P =.2) did not differ between the 2 groups. At 2 months' evaluation, a healing scar was found in 67 patients (89%) from group I and 72 patients (96%) from group II. A relapse of the fissure was observed in 6 patients (8%) from group I who had a healing scar at 1 month, and 2 other patients never healed. A persistent fissure was present in 3 patients from group II who had no other symptoms. Botulinum toxin injected into the internal anal sphincter is effective in managing anal fissures and avoiding permanent complications. All patients were treated with the active drug and healed after 1 or 2 successive treatments. The results also confirm that higher doses account for a higher success rate, with little increase in complications or side effects, which is probably related to the diffusion of the toxin to the external sphincter.

  2. A randomized trial of oral vs. topical diltiazem for chronic anal fissures.

    PubMed

    Jonas, M; Neal, K R; Abercrombie, J F; Scholefield, J H

    2001-08-01

    Chemical sphincterotomy has proved effective in treating chronic anal fissure. Glyceryl trinitrate is the most widely used agent, and topical 0.2 percent glyceryl trinitrate ointment heals up to two thirds of chronic anal fissures. Unfortunately, however, many patients experience troublesome headaches as a side effect of this treatment. This study assessed the effectiveness of oral and topical diltiazem in healing chronic fissures. Fifty consecutive patients with chronic anal fissures were randomly assigned to receive oral (60 mg) or topical (2 percent gel) diltiazem twice daily for up to eight weeks. Anal manometry was performed before and after the first dose, and blood pressure was recorded at 15-minute intervals. Patients were reviewed fortnightly, pain was expressed with a visual linear analog scale, blood pressure was recorded, fissure healing was assessed, and side effects were noted. Twenty-four patients received oral diltiazem, and 26 received topical diltiazem. Mean (+/- standard error of the mean) maximum resting anal pressures fell by 15 and 23 percent from 95 +/- 4 to 81 +/- 4 and from 102 +/- 5 to 79 +/- 5 cm H2O in the two groups, respectively. There was no significant reduction in blood pressure during the study or at follow-up in either group. Fissure healing was complete in 9 patients (38 percent) receiving oral diltiazem and 15 (65 percent) on topical treatment by eight weeks. Oral diltiazem caused side effects in eight patients (rash, two; headaches, two; nausea or vomiting, three; reduced smell and taste, one), whereas no side effects were seen in those receiving topical therapy (P = 0.001). Oral and topical diltiazem heal chronic anal fissures. Topical diltiazem is more effective, achieving healing rates comparable to those reported with topical nitrates, with significantly fewer side effects.

  3. The metallurgical integrity of the frit vent assembly diffusion bond

    SciTech Connect

    Ulrich, G.B.

    1994-06-01

    Iridium alloy clad vent sets (CVSs) are now being made by Energy Systems at the Oak Ridge Y-12 Plant. These CVSs are being made for the US Department of Energy`s (NE-53) General Purpose Heat Source- Radioisotope Thermoelectric Generator (GPHS-RTG) program, which is to supply electrical power for the National Aeronautics and Space Administration`s Cassini mission to Saturn. A GPHS-RTG has 72 CVSs. Each CVS encapsulates one {sup 238}PuO{sub 2} fuel pellet. The helium gas produced from the alpha decay of the {sup 238}Pu is vented through a nominal 0.45-mm-diam hole in the vent cup of each CVS. A frit vent assembly that is electron beam welded over the vent hole allows helium gas to escape but prevents plutonia fines from exiting. The metallurgical integrity of frit vent assemblies produced by Martin Marietta Energy Systems, Inc. (Energy Systems) were compared with those produced earlier by EG&G-Mound Applied Technology, Inc. (EG&G-MAT). Scanning electron microscope (SEM) photographs were taken (at magnifications of from 126X to 1,000X) of the starting frit vent powder and the diffusion-bonded powder in finished frit vent assemblies produced by Energy Systems and EG&G-MAT. Frit vent assemblies also were metallographically prepared and visually examined/photographed at magnifications of from 50X to 1,000X. The SEM and metallographic examinations of the particle-to-particle and particle-to-foil component diffusion bonds indicated that the Energy Systems-produced and EG&G-MAT-produced frit vent assemblies have comparable metallurgical integrity. Statistical analysis of the Energy Systems production data shows that the frit vent manufacturing yield is 91%.

  4. The metallurgical integrity of the frit vent assembly diffusion bond

    NASA Astrophysics Data System (ADS)

    Ulrich, G. B.

    1994-06-01

    Iridium alloy clad vent sets (CVS's) are now being made by Energy Systems at the Oak Ridge Y-12 Plant. These CVS's are being made for the US Department of Energy's (NE-53) General Purpose Heat Source- Radioisotope Thermoelectric Generator (GPHS-RTG) program, which is to supply electrical power for the National Aeronautics and Space Administration's Cassini mission to Saturn. A GPHS-RTG has 72 CVS'. Each CVS encapsulates one (238)PuO2 fuel pellet. The helium gas produced from the alpha decay of the (238)Pu is vented through a nominal 0.45-mm-diam hole in the vent cup of each CVS. A frit vent assembly that is electron beam welded over the vent hole allows helium gas to escape but prevents plutonia fines from exiting. The metallurgical integrity of frit vent assemblies produced by Martin Marietta Energy Systems, Inc. (Energy Systems) were compared with those produced earlier by EG&G-Mound Applied Technology, Inc. (EG&G-MAT). Scanning electron microscope (SEM) photographs were taken (at magnifications of from 126x to 1,000x) of the starting frit vent powder and the diffusion-bonded powder in finished frit vent assemblies produced by Energy Systems and EG&G-MAT. Frit vent assemblies also were metallographically prepared and visually examined/photographed at magnifications of from 50x to 1,000x. The SEM and metallographic examinations of the particle-to-particle and particle-to-foil component diffusion bonds indicated that the Energy Systems-produced and EG&G-MAT-produced frit vent assemblies have comparable metallurgical integrity. Statistical analysis of the Energy Systems production data shows that the frit vent manufacturing yield is 91%.

  5. Fluid dynamics in explosive volcanic vents and craters

    NASA Astrophysics Data System (ADS)

    Ogden, Darcy

    2011-12-01

    Explosive volcanic jets can transition to buoyant plumes or collapse to form pyroclastic density currents depending on their ability to entrain and heat the ambient air. Recent one-dimensional (1D) analysis shows that fluid acceleration through volcanic vents and craters changes the velocity and pressures within these jets sufficiently enough to be a first order control on plume dimensions and therefore air entrainment and column stability (Koyaguchi et al., 2010). These 1D studies are only applicable to craters and vents with angles of less than about 30° to vertical. Using analytical formulations and numerical simulations, this study describes 2D effects of shallowly dipping vents and craters on volcanic eruptions. The effect of vents on acceleration and expansion of eruptive mixtures of ash and gas is described as a force imparted on the fluid by the vent wall, the wall force ( Fw). This force is a measure of the momentum coupling between an eruption and the solid earth that takes place in the vent. Rapid divergence of supersonic eruptive fluid within shallowly dipping vents occurs via Prandtl-Meyer expansion, which results in different pressure and velocity fields than those predicted by 1D analysis. This expansion decreases Fw and the vertical acceleration experienced by the eruptive fluid in the vent. For jets predicted by 1D analysis to exit the vent at supersonic velocities and at atmospheric pressure, this decrease in Fw will cause an increase in the predicted plume area, decreasing column stability. The complex 2D shape of volcanic vents can change jet structure (presence and location of shock waves) and preclude the development of jets that exit the vent supersonically with no internal standing shock waves (i.e., perfectly expanded or pressure balanced jets). These significant complications in jet structure and increase in plume radius may result in changes to air entrainment, plume stability, and tephra distribution.

  6. Diffuse flow from hydrothermal vents. Doctoral thesis

    SciTech Connect

    Trivett, D.A.

    1991-08-01

    The effluent from a collection of diffuse hydrothermal vents was modelled to determine the fate of the source of flow under typical environmental conditions at seafloor spreading centers. A laboratory simulation was conducted to test an analytic model of diffuse plume rise. The results showed that diffuse plumes are likely to remain near the seafloor, with their maximum rise height scaled with the diameter of the source of diffuse flow. The entrainment of ambient seawater into these plumes is limited by the proximity to the seafloor, thus slowing the rate of dilution. The model of diffuse plume behaviour was used to guide the design and implementation of a scheme for monitoring the flow from diffuse hydrothermal vents in the ocean. A deployment of an array at the Southern Juan de Fuca Ridge yielded measurements of a variety of diffuse plume properties, including total heat output. Two distinct sources of hydrothermal flow were detected during the field deployment. The larger source was 1-1.5km north of the instrument array, and its energy output was 450 + or - 270MW. A smaller source was located 100m east of one instrument in the array. The energy output of the source was 12 + or - 8MW. The rise heights of the centerlines of these plumes were 45m and 10m, respectively.

  7. Geomicrobiology of deep-sea hydrothermal vents.

    PubMed

    Jannasch, H W; Mottl, M J

    1985-08-23

    During the cycling of seawater through the earth's crust along the mid-ocean ridge system, geothermal energy is transferred into chemical energy in the form of reduced inorganic compounds. These compounds are derived from the reaction of seawater with crustal rocks at high temperatures and are emitted from warm (vents at depths of 2000 to 3000 meters. Chemolithotrophic bacteria use these reduced chemical species as sources of energy for the reduction of carbon dioxide (assimilation) to organic carbon. These bacteria form the base of the food chain, which permits copious populations of certain specifically adapted invertebrates to grow in the immediate vicinity of the vents. Such highly prolific, although narrowly localized, deep-sea communities are thus maintained primarily by terrestrial rather than by solar energy. Reduced sulfur compounds appear to represent the major electron donors for aerobic microbial metabolism, but methane-, hydrogen-, iron-, and manganese-oxidizing bacteria have also been found. Methanogenic, sulfur-respiring, and extremely thermophilic isolates carry out anaerobic chemosynthesis. Bacteria grow most abundantly in the shallow crust where upwelling hot, reducing hydrothermal fluid mixes with downwelling cold, oxygenated seawater. The predominant production of biomass, however, is the result of symbiotic associations between chemolithotrophic bacteria and certain invertebrates, which have also been found as fossils in Cretaceous sulfide ores of ophiolite deposits.

  8. MAVEN Contamination Venting and Outgassing Analysis

    NASA Technical Reports Server (NTRS)

    Petro, Elaine M.; Hughes, David W.; Secunda, Mark S.; Chen, Philip T.; Morrissey, James R.; Riegle, Catherine A.

    2014-01-01

    Mars Atmosphere and Volatile EvolutioN (MAVEN) is the first mission to focus its study on the Mars upper atmosphere. MAVEN will study the evolution of the Mars atmosphere and climate, by examining the conduit through which the atmosphere has to pass as it is lost to the upper atmosphere. An analysis was performed for the MAVEN mission to address two distinct concerns. The first goal of the analysis was to perform an outgassing study to determine where species outgassed from spacecraft materials would redistribute to and how much of the released material might accumulate on sensitive surfaces. The second portion of the analysis serves to predict what effect, if any, Mars atmospheric gases trapped within the spacecraft could have on instrument measurements when re-released through vents. The re-release of atmospheric gases is of interest to this mission because vented gases from a higher pressure spacecraft interior could bias instrument measurements of the Mars atmosphere depending on the flow rates and directions.

  9. In vitro evaluation of shear bond strength and microleakage of different pit and fissure sealants

    PubMed Central

    Babaji, Prashant; Vaid, Shivali; Deep, S.; Mishra, Samvit; Srivastava, Madhulika; Manjooran, Thomas

    2016-01-01

    Aim and Objectives: Fissure caries is most common in children due to deep pit and fissures. Pit and fissure areas on the occlusal surface of the teeth make them susceptible to dental caries, which need to be prevented or restored. Fissures sealant reduces the risk of occlusal caries. The present study was done to evaluate microleakage and shear bond strength of various fissure sealants. Materials and Methods: Thirty-six extracted molars were randomly allocated equally (n = 12) into three groups with three different sealants to evaluate shear bond strength and microleakage at sealant space. The shear bond strengths was evaluated with one-way analysis of variance and microleakage by Kruskal-Wallis nonparametric test using the Statistical Package for the Social Sciences version 18.0 (Chicago: SPSS Inc, 2009). Results: Tetric flow (16.8 MPa) recorded the highest shear bond strength and the difference was statistically significant with enamel loc (12.8 MPa). There was no statistically significant difference in relation to microleakage (P > 0.05) in the tested groups. Conclusions: Tetric flow recorded the highest shear bond strength and the difference was statistically significant with enamel loc. However, there was no statistically significant difference among the groups regarding microleakage. PMID:27652241

  10. Effect of ozone pretreatment on the microleakage of pit and fissure sealants.

    PubMed

    Cehreli, S Burcak; Yalcinkaya, Zeynep; Guven-Polat, Gunseli; Cehreli, Zafer Cavit

    2010-01-01

    This study investigated the effect of ozone pretreatment on the microleakage and marginal integrity of pit and fissure sealants placed with or without a self-etch 6th generation adhesive. Freshly-extracted, human third molars were randomly assigned into two main groups (n = 48): Group A: Fissures were pretreated with ozone; Group B: Fissures were left untreated. The teeth were further randomly divided into two subgroups (n = 24/each) so that half of teeth were sealed with a conventional fissure sealant (Fissurit F, Voco, Germany), while the remaining half received the same sealant bonded with a self-etch adhesive (Clearfil Protect Bond, Kuraray, Japan). Following thermal cycling (1000X), the specimens were subjected to dye penetration within 0.5% basic fuchsin for 24h. The extent of dye penetration was measured by image analysis. Kruskal Wallis and Mann-Whitney U tests were used for statistical analysis of the data (p = 0.05). Two randomly-selected sections from each group were observed under SEM RESULTS: In all groups, ozone pretreatment significantly reduced the extent of microleakage (p < 0.001). SEM investigation demonstrated better adaptation of the sealants in ozone-pretreated groups. Clearfil Protect Bond did not improve the marginal seal of Fissurit F (p > 0.05). Ozone pretreatment favorably affected the marginal sealing ability of the tested fissure sealants.

  11. Anal fissures and anal scars in anal abuse--are they significant?

    PubMed

    Pierce, Agnes M

    2004-05-01

    The notes of 214 children who, over a period of 7 years, had been referred after an allegation or a suspicion of any form of child abuse, were examined retrospectively to establish the pattern of injury found, especially with regard to anal fissures or scars. These were all children who had had their genitalia examined at the time of their referral. In 81 children (Group A) who had no history or evidence of sexual abuse, two fissures were found, both with medical explanations for their presence. In 83 (Group B) who alleged sexual abuse but denied anal abuse, nine (11%) had fissures or scars, and in four of the nine there was a history of significant constipation at some time. In 50 children (Group C) who had a strong history of anal abuse, 41 (84%) had fissures or scars. The diagnosis in 13 of these cases was considered definite because there was a confession or guilty plea from the abuser; in the remainder, the diagnosis was "not proven" despite a strong history or gross anal signs and regardless of the verdict in court proceedings. The significance of the findings was discussed with a view to clarifying the relative importance of anal fissures in children with a strong history of anal abuse.

  12. V-Y advancement flap as first-line treatment for all chronic anal fissures.

    PubMed

    Chambers, William; Sajal, Rai; Dixon, Anthony

    2010-05-01

    It was suggested that anal advancement flap be used to treat patients with chronic anal fissures that have failed medical management and have a low-pressure sphincter complex. We wished to assess anal advancement flap as a treatment for all chronic anal fissures. All patients with chronic anal fissures regardless of their previous management underwent V-Y advancement flap. Patient demographics, symptom duration, previous treatments, short-term postoperative outcome and long-term follow-up were recorded. Fifty-four consecutive patients, median age 39 years (22-66), underwent a V-Y advancement flap over a 7-year period; 34 were men. Duration of symptoms ranged from 2 to 36 months with a median of 8 months. Forty-two patients (78%) had failed a previous therapy: glyceryl trinitrate (GTN) (25), GTN and diltiazem (16) and lateral sphincterotomy (one). Wound dehiscence occurred in three patients of which only one required a surgical intervention. On follow-up at 6 months, all but one patient had a healed wound and was asymptomatic. We have shown excellent rates of healing of chronic anal fissures treated with a V-Y advancement flap regardless of sphincter pressures, previous treatment and symptom chronicity. These results show the technique can be applied to all chronic fissures with success and used as a primary therapy.

  13. Endoanal ultrasonographic evaluation of an unhealed anal fissure after the lateral internal sphincterotomy.

    PubMed

    Yucel, E; Akin, M L; Sucullu, I; Filiz, A I; Ozdemir, Y; Yildiz, M

    2013-01-01

    The aim of this study was to evaluate the outcomes of the lateral internal sphincterotomy in patients who had unhealed anal fissures using the endoanal ultrasonography. Lateral internal sphincterotomy is an effective method in treatment of chronic anal fissures, but it is associated with 1 to 5 % unhealing and recurrence rates. Endoanal ultrasonography can be used to evaluate the sphincterotomy and the efficiency of the treatment. Totally, 40 patients with unhealed anal fissures after the lateral internal sphincterotomy were enrolled consecutively. The fissures were diagnosed by proctologic examination in every patient. The results of sphincterotomy were evaluated by the endoanal ultrasonography. There were 23 men and 17 women with the median age 29.7 years (range, 20-44 years). Using the endoanal ultrasonography, an incomplete internal sphincterotomy was detected in 26 of patients. In 12 patients, while the internal sphincter was completely intact, a superficial (subcutaneous) external anal sphincterotomy was found. In two patients, although the internal sphincterotomy was observed to be sufficient, a localized abscess formation of less than 1 cm was detected at the anal crypts level. The use of endoanal ultrasonography in patients with unhealed or recurrent anal fissure is a beneficial diagnostic method in assessing the situations of sphincters after the lateral internal sphincterotomy. Although the lateral internal sphincterotomy is a successful surgical treatment and can be performed easily as an outpatient procedure, it should be performed with the correct and rigorously surgical technique (Tab. 2, Fig. 3, Ref. 31).

  14. 0.4% glyceryl trinitrate ointment: new drug. Not useful for anal fissures.

    PubMed

    2008-04-01

    (1) Anal fissures are very painful but often heal spontaneously. After eliminating other diagnoses, various treatments can be tried while waiting for fissures to heal: warm seat baths, local anaesthetics, and adequate fibre and fluid intake. (2) Clinical evaluation of glyceryl trinitrate 0.4% ointment, a nitrate derivative, is mainly based on a double-blind trial versus excipient in 193 adults with "chronic" fissures. This trial failed to show a clinically relevant analgesic effect of glyceryl trinitrate 0.4%, with only a 3-mm difference versus the excipient on a 100-mm pain rating scale. In another trial including 229 patients, neither 0.2% nor 0.4% glyceryl trinitrate was more effective on pain than placebo. (3) Another placebo-controlled trial including 304 adults treated for 8 weeks showed no efficacy of various doses of glyceryl trinitrate, versus the excipient, on the healing of anal fissures. (4) The most frequent adverse effect, as expected with a nitrate derivative, is headache, which affects about two-thirds of patients and is severe in 20% of cases. Abrupt-onset hypotension is a risk during concomitant use of other vasodilatory drugs. (5) There are no data on pregnant women exposed to glyceryl trinitrate. (6) In summary, glyceryl trinitrate 0.4% ointment does not reduce the pain linked to chronic anal fissures, but it does carry a risk of sometimes severe headache. It is best to continue using simple, non-aggressive treatments.

  15. Quality of life in patients with chronic anal fissure after topical treatment with diltiazem

    PubMed Central

    Tsunoda, Akira; Kashiwagura, Yasuharu; Hirose, Ken-ichi; Sasaki, Tadanori; Kano, Nobuyasu

    2012-01-01

    AIM: To assess the physical and mental health of fissure patients before and after topical treatment with diltiazem. METHODS: Consecutive patients were enrolled prospectively into the study. Quality of life was measured with the short-forum 36 health survey (SF-36) before and after 6-wk treatment with diltiazem. Patients scored symptoms of pain, bleeding, and irritation using numeral rating scales at the initial and follow-up visits. Fissure healing was assessed and side effects were noted. RESULTS: Fissures healed in 21 of 30 (70%) patients. There were significant reductions in the scores of pain, bleeding, and irritation after 1 wk of treatment, respectively. Four patients experienced perianal itching and one patient reported headache. When measured at baseline, pain and irritation showed a negative impact on two of the eight subscales on the SF-36, respectively (bodily pain and social functioning for pain; vitality and mental health for irritation). Repeating the SF-36 showed an improvement in bodily pain (P = 0.001). Patients whose fissures healed reported an improvement in bodily pain, health-perception, vitality, and mental health (P < 0.05). CONCLUSION: Successful treatment of chronic anal fissure with topical diltiazem leads to improvement in health-related quality of life. PMID:23494072

  16. Comparison of Topical Nifedipine With Oral Nifedipine for Treatment of Anal Fissure: A Randomized Controlled Trial

    PubMed Central

    Golfam, Farzaneh; Golfam, Parisa; Golfam, Babak; Pahlevani, Puyan

    2014-01-01

    Background: Medical sphincterotomy has gained popularity as a treatment for anal fissure. Calcium channel blockers in topical forms could also be appropriate with low adverse effects. Objectives: This was a prospective randomized controlled trial to compare topical and oral nifedipine in the treatment of chronic anal fissure. Patients and Methods: A prospective randomized controlled trial was conducted at two centers of Shahed University. One hundred and thirty patients with chronic anal fissure aged 18 to 60 years managed in our clinics were included in this study. The patients were randomly divided into two groups. Sixty-five patients received topical nifedipine (TN) and the same number received oral nifedipine (ON). Results: Ulcer healing occurred in 43 (73.33%) of topical nifedipine group compared to 29 (49.5%) patients in oral nifedipine, which was significantly different (P < 0.05). Side effects such as headache and flushing in oral nifedipine group were more prevalent than topical nifedipine, which was statistically different. Recurrence rates were the same after six months of follow-up. Conclusions: Although oral nifedipine can reduce symptom and signs of anal fissure, topical nifedipine has a superior role for anal fissure treatment with higher healing rate and lower side effects. PMID:25389477

  17. Maps showing water-level declines, land subsidence, and earth fissures in south-central Arizona

    USGS Publications Warehouse

    Laney, R.L.; Raymond, R.H.; Winikka, C.C.

    1978-01-01

    From 1915 to 1975, more than 109 million acre-feet of ground water was withdrawn from about 4,500 square miles in Pinal and Maricopa Counties in south-central Arizona. The volume of water withdrawn greatly exceeds the volume of natural recharge, and water levels have been declining since 1923. As a result of the water-level declines, the land surface has subsided, the alluvial deposits have been subjected to stress, and earth fissures have developed. Land subsidence and earth fissures have damaged public and private properties. Subsidence and fissures will continue to occur as long as ground water is being mined and water levels continue to decline. As urban development expands, land subsidence and earth fissures will have an increasing socioeconomic impact. Information on maps includes change in water levels, measurements of land subsidence, and location of earth fissures. A section showing land subsidence between Casa Grande and the Picacho Peak Interchange also is included. Scale 1:250,000. (Woodard-USGS)

  18. Low energy manual anal stretch: an approach in the treatment of chronic anal fissure.

    PubMed

    Gaj, Fabio; Biviano, Ivano; Candeloro, Laura

    2017-04-01

    Anal fissure is a tear in the epitelial lining of the anal canal. This is a very common anorectal disorder, but the choice of treatment is unclear. Sphincterotomy is effective but it is affected by a high risk of fecal incontinence. Manual anal stretch is aN efficacious, economic and safe maneuver. The aim of this prospective study was to assess the safety and effectiveness of anal stretch in resolving chronic anal fissures. Twenty-five patients with a clinical diagnosis of chronic anal fissure were submitted to anal stretch. All patients were submitted to anal stretch, after clinical evaluation. All patients were studied at basal time, and at 7 days, 3, 6 and 12 months after the treatment. At 3 months and 6 months after the anal stretch, 88% and 94% of patients showed a resolution of anal fissures and only 12% have relapsed at 12 months, without complications, such as faecal incontinence. The anal stretch appears to induce better resolution of chronic anal fissure with a very low risk of fecal incontinence.

  19. Thermodynamic Vent System Test in a Low Earth Orbit Simulation

    NASA Technical Reports Server (NTRS)

    VanOverbeke, Thomas J.

    2004-01-01

    A thermodynamic vent system for a cryogenic nitrogen tank was tested in a vacuum chamber simulating oxygen storage in low earth orbit. The nitrogen tank was surrounded by a cryo-shroud at -40 F. The tank was insulated with two layers of multi-layer insulation. Heat transfer into cryogenic tanks causes phase change and increases tank pressure which must be controlled. A thermodynamic vent system was used to control pressure as the location of vapor is unknown in low gravity and direct venting would be wasteful. The thermodynamic vent system consists of a Joule-Thomson valve and heat exchanger installed on the inlet side of the tank mixer-pump. The combination is used to extract thermal energy from the tank fluid, reducing temperature and ullage pressure. The system was sized so that the tank mixer-pump operated a small fraction of the time to limit motor heating. Initially the mixer used sub-cooled liquid to cool the liquid-vapor interface inducing condensation and pressure reduction. Later, the thermodynamic vent system was used. Pressure cycles were performed until steady-state operation was demonstrated. Three test runs were conducted at tank fills of 97, 80, and 63 percent. Each test was begun with a boil-off test to determine heat transfer into the tank. The lower tank fills had time averaged vent rates very close to steady-state boil-off rates showing the thermodynamic vent system was nearly as efficient as direct venting in normal gravity.

  20. Where are the undiscovered hydrothermal vents on oceanic spreading ridges?

    NASA Astrophysics Data System (ADS)

    Beaulieu, Stace E.; Baker, Edward T.; German, Christopher R.

    2015-11-01

    In nearly four decades since the discovery of deep-sea vents, one-third of the length of global oceanic spreading ridges has been surveyed for hydrothermal activity. Active submarine vent fields are now known along the boundaries of 46 out of 52 recognized tectonic plates. Hydrothermal survey efforts over the most recent decade were sparked by national and commercial interests in the mineral resource potential of seafloor hydrothermal deposits, as well as by academic research. Here we incorporate recent data for back-arc spreading centers and ultraslow- and slow-spreading mid-ocean ridges (MORs) to revise a linear equation relating the frequency of vent fields along oceanic spreading ridges to spreading rate. We apply this equation globally to predict a total number of vent fields on spreading ridges, which suggests that ~900 vent fields remain to be discovered. Almost half of these undiscovered vent fields (comparable to the total of all vent fields discovered during 35 years of research) are likely to occur at MORs with full spreading rates less than 60 mm/yr. We then apply the equation regionally to predict where these hydrothermal vents may be discovered with respect to plate boundaries and national jurisdiction, with the majority expected to occur outside of states' exclusive economic zones. We hope that these predictions will prove useful to the community in the future, in helping to shape continuing ridge-crest exploration.

  1. 46 CFR 153.362 - Venting system drain.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Venting system drain. 153.362 Section 153.362 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Venting...

  2. 46 CFR 153.354 - Venting system inlet.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Venting system inlet. 153.354 Section 153.354 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Venting...

  3. Vents to the north of the south elevation, note the ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Vents to the north of the south elevation, note the hooded vents along the elevation - Over-the-Horizon Backscatter Radar Network, Christmas Valley Radar Site Transmit Sector Six Transmitter Building, On unnamed road west of Lost Forest Road, Christmas Valley, Lake County, OR

  4. 46 CFR 153.1500 - Venting system rupture disks.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Venting system rupture disks. 153.1500 Section 153.1500....1500 Venting system rupture disks. The master shall ensure that a relief valve exposed to a cargo after the failure of a rupture disk or breaking pin is cleaned and operates properly before the next cargo...

  5. 46 CFR 56.50-85 - Tank-vent piping.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... liquids, such as fuel, ship's stores, cargo, or ballast, are carried. (1) The structural arrangement in... liquids, such as lubricating oil, may terminate in the machinery space, provided— (i) The vents are... combustible liquids are not heated; and (iii) The vents terminate above the deep load waterline if the tanks...

  6. Antarctic marine biodiversity and deep-sea hydrothermal vents.

    PubMed

    Chown, Steven L

    2012-01-01

    The diversity of many marine benthic groups is unlike that of most other taxa. Rather than declining from the tropics to the poles, much of the benthos shows high diversity in the Southern Ocean. Moreover, many species are unique to the Antarctic region. Recent work has shown that this is also true of the communities of Antarctic deep-sea hydrothermal vents. Vent ecosystems have been documented from many sites across the globe, associated with the thermally and chemically variable habitats found around these, typically high temperature, streams that are rich in reduced compounds and polymetallic sulphides. The animal communities of the East Scotia Ridge vent ecosystems are very different to those elsewhere, though the microbiota, which form the basis of vent food webs, show less differentiation. Much of the biological significance of deep-sea hydrothermal vents lies in their biodiversity, the diverse biochemistry of their bacteria, the remarkable symbioses among many of the marine animals and these bacteria, and the prospects that investigations of these systems hold for understanding the conditions that may have led to the first appearance of life. The discovery of diverse and unusual Antarctic hydrothermal vent ecosystems provides opportunities for new understanding in these fields. Moreover, the Antarctic vents south of 60°S benefit from automatic conservation under the Convention on the Conservation of Antarctic Marine Living Resources and the Antarctic Treaty. Other deep-sea hydrothermal vents located in international waters are not protected and may be threatened by growing interests in deep-sea mining.

  7. Hydrogen Vent Ground Umbilical Quick Disconnect - Flight Seal Advanced Development

    NASA Technical Reports Server (NTRS)

    Girard, Doug; Jankowski, Fred; Minich, Mark C.; Yu, Weiping

    2012-01-01

    This project is a team effort between NASA Engineering (NE) and Team QNA Engineering personnel to provide support for the Umbilical Systems Development project which is funded by Advanced Exploration Systems (AES) and 21st Century Launch Complex. Specifically, this project seeks to develop a new interface between the PPBE baselined Legacy SSP LH2 Vent Arm QD probe and SLS vent seal.

  8. 49 CFR 192.187 - Vaults: Sealing, venting, and ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Vaults: Sealing, venting, and ventilation. 192.187... TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Design of Pipeline Components § 192.187 Vaults: Sealing, venting, and ventilation. Each underground vault or closed top...

  9. Vented Compression Molding of Granule-Filled Resins

    NASA Technical Reports Server (NTRS)

    Mccree, J. O.; Erwin, L.

    1985-01-01

    Resins filled with granules formed to final size and shape in new process. New vented compression molding method takes less time than conventional method. Vacuum-bagging and machining stages eliminated. Part emerges from mold in final size and shape. Suitable for making variety of parts with simple shapes, vented compression molding takes less time and cost less than older processes.

  10. 40 CFR 63.983 - Closed vent systems.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Closed vent systems. 63.983 Section 63.983 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED... Emission Standards for Closed Vent Systems, Control Devices, Recovery Devices and Routing to a Fuel...

  11. 40 CFR 63.983 - Closed vent systems.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 10 2011-07-01 2011-07-01 false Closed vent systems. 63.983 Section 63.983 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED... Emission Standards for Closed Vent Systems, Control Devices, Recovery Devices and Routing to a Fuel...

  12. 40 CFR 65.143 - Closed vent systems.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 15 2011-07-01 2011-07-01 false Closed vent systems. 65.143 Section 65.143 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONSOLIDATED FEDERAL AIR RULE Closed Vent Systems, Control Devices, and Routing to a Fuel Gas System or...

  13. Deep-sea primary production at the Galapagos hydrothermal vents

    SciTech Connect

    Karl, D.M.; Wirsen, C.O.; Jannasch, H.W.

    1980-03-21

    Dense animal populations surrounding recently discovered hydrothermal vents at the Galapagos Rift sea-floor spreading center, 2550 meters deep, are probably sustained by microbial primary production. Energy in the form of geothermically reduced sulfur compounds emitted from the vents is liberated during oxidation and used for the reduction of carbon dioxide to organic matter by chemosynthetic bacteria.

  14. Zero-G thermodynamic vent system for shuttle/Centaur

    NASA Technical Reports Server (NTRS)

    Niggemann, Richard E.

    1987-01-01

    Viewgraphs are presented showing drawings of Centaur configurations, the Thermodynamic Vent System (TVS), the mixer pump, and the hydrogen vent motor pump inverter. A cryogenic performance summary is given in chart form. The TVS liquid flow operation and vapor flow operation are diagrammed.

  15. 46 CFR 119.450 - Vent pipes for fuel tanks.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Vent pipes for fuel tanks. 119.450 Section 119.450... Specific Machinery Requirements § 119.450 Vent pipes for fuel tanks. (a) Each unpressurized fuel tank must be fitted with a pipe connected to the highest point of the tank. (b) The minimum net cross...

  16. An authoritative global database for active submarine hydrothermal vent fields

    NASA Astrophysics Data System (ADS)

    Beaulieu, Stace E.; Baker, Edward T.; German, Christopher R.; Maffei, Andrew

    2013-11-01

    The InterRidge Vents Database is available online as the authoritative reference for locations of active submarine hydrothermal vent fields. Here we describe the revision of the database to an open source content management system and conduct a meta-analysis of the global distribution of known active vent fields. The number of known active vent fields has almost doubled in the past decade (521 as of year 2009), with about half visually confirmed and others inferred active from physical and chemical clues. Although previously known mainly from mid-ocean ridges (MORs), active vent fields at MORs now comprise only half of the total known, with about a quarter each now known at volcanic arcs and back-arc spreading centers. Discoveries in arc and back-arc settings resulted in an increase in known vent fields within exclusive economic zones, consequently reducing the proportion known in high seas to one third. The increase in known vent fields reflects a number of factors, including increased national and commercial interests in seafloor hydrothermal deposits as mineral resources. The purpose of the database now extends beyond academic research and education and into marine policy and management, with at least 18% of known vent fields in areas granted or pending applications for mineral prospecting and 8% in marine protected areas.

  17. "Venting" in the Workplace: An Ethnographic Study among Resident Assistants.

    ERIC Educational Resources Information Center

    Burchard, Brendon

    The term "venting" has been used interchangeably with negatively-connotated words like "outburst,""bitching,""complaining," and with more functional words like "disclosing." A literature review of venting showed that researchers have approached the term from multiple perspectives. Because of the…

  18. 49 CFR 192.187 - Vaults: Sealing, venting, and ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Vaults: Sealing, venting, and ventilation. 192.187... Components § 192.187 Vaults: Sealing, venting, and ventilation. Each underground vault or closed top pit... ventilating effect of a pipe 4 inches (102 millimeters) in diameter; (2) The ventilation must be enough...

  19. 49 CFR 192.187 - Vaults: Sealing, venting, and ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Vaults: Sealing, venting, and ventilation. 192.187... Components § 192.187 Vaults: Sealing, venting, and ventilation. Each underground vault or closed top pit... ventilating effect of a pipe 4 inches (102 millimeters) in diameter; (2) The ventilation must be enough...

  20. 40 CFR 63.1321 - Batch process vents provisions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... classified as Group 1 shall comply with the reference control technology requirements for Group 1 batch...) National Emission Standards for Hazardous Air Pollutant Emissions: Group IV Polymers and Resins § 63.1321... vents shall comply with the requirements in §§ 63.1322 through 63.1327. The batch process vent group...

  1. 46 CFR 38.20-1 - Venting-T/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Venting-T/ALL. 38.20-1 Section 38.20-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS LIQUEFIED FLAMMABLE GASES Venting and Ventilation § 38.20-1 Venting—T/ALL. (a) Each safety relief valve installed on a cargo tank shall be connected to...

  2. 46 CFR 38.20-5 - Venting-T/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Venting-T/ALL. 38.20-5 Section 38.20-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS LIQUEFIED FLAMMABLE GASES Venting and Ventilation § 38.20-5 Venting—T/ALL. (a) Safety relief valves on cargo tanks in barges may be connected...

  3. Assessment of Literature Related to Combustion Appliance Venting Systems

    SciTech Connect

    Rapp, V. H.; Less, B. D.; Singer, B. C.; Stratton, J. C.; Wray, C. P.

    2015-02-01

    In many residential building retrofit programs, air tightening to increase energy efficiency is often constrained by safety concerns with naturally vented combustion appliances. Tighter residential buildings more readily depressurize when exhaust equipment is operated, making combustion appliances more prone to backdraft or spill combustion exhaust into the living space. Several measures, such as installation guidelines, vent sizing codes, and combustion safety diagnostics, are in place with the intent to prevent backdrafting and combustion spillage, but the diagnostics conflict and the risk mitigation objective is inconsistent. This literature review summarizes the metrics and diagnostics used to assess combustion safety, documents their technical basis, and investigates their risk mitigations. It compiles information from the following: codes for combustion appliance venting and installation; standards and guidelines for combustion safety diagnostics; research evaluating combustion safety diagnostics; research investigating wind effects on building depressurization and venting; and software for simulating vent system performance.

  4. Natural Gas Venting on the Northern Cascadia Margin

    NASA Astrophysics Data System (ADS)

    Scherwath, M.; Riedel, M.; Roemer, M.; Paull, C. K.; Spence, G.; Veloso, M.

    2016-12-01

    Over the past decades, hundreds of natural gas vents have been observed along the Northern Cascadia Margin in the Northeast Pacific, and we present a summary of these observations from offshore Vancouver Island, BC, Canada. We have gathered observed locations and analyzed original data from published literature as well as research cruises and fishing sonar from various archives. By far the highest accumulation of gas vent locations appear both shallow (100-200 m) and concentrated towards the mouth of the Juan de Fuca Strait, however these observations are naturally biased toward the distribution of the observation footprints. Normalized observations confirm the shallow high concentrations of gas vents but also establish some deeper sections of focused venting activity. We will speculate about the reasons behind the distribution, focus on specific examples, extrapolate for rough margin flux rate ranges and comment on short-comings and future directions for margin-wide gas vent studies.

  5. Feasibility and Safety Assessment for Advanced Reactor Concepts Using Vented Fuel

    SciTech Connect

    Klein, Andrew; Matthews, Topher; Lenhof, Renae; Deason, Wesley; Harter, Jackson

    2015-01-16

    Recent interest in fast reactor technology has led to renewed analysis of past reactor concepts such as Gas Fast Reactors and Sodium Fast Reactors. In an effort to make these reactors more economic, the fuel is required to stay in the reactor for extended periods of time; the longer the fuel stays within the core, the more fertile material is converted into usable fissile material. However, as burnup of the fuel-rod increases, so does the internal pressure buildup due to gaseous fission products. In order to reach the 30 year lifetime requirements of some reactor designs, the fuel pins must have a vented-type design to allow the buildup of fission products to escape. The present work aims to progress the understanding of the feasibility and safety issues related to gas reactors that incorporate vented fuel. The work was separated into three different work-scopes: 1. Quantitatively determine fission gas release from uranium carbide in a representative helium cooled fast reactor; 2. Model the fission gas behavior, transport, and collection in a Fission Product Vent System; and, 3. Perform a safety analysis of the Fission Product Vent System. Each task relied on results from the previous task, culminating in a limited scope Probabilistic Risk Assessment (PRA) of the Fission Product Vent System. Within each task, many key parameters lack the fidelity needed for comprehensive or accurate analysis. In the process of completing each task, the data or methods that were lacking were identified and compiled in a Gap Analysis included at the end of the report.

  6. Ventrally emigrating neural tube (VENT) cells: a second neural tube-derived cell population.

    PubMed

    Dickinson, Douglas P; Machnicki, Michal; Ali, Mohammed M; Zhang, Zhanying; Sohal, Gurkirpal S

    2004-08-01

    Two embryological fates for cells of the neural tube are well established. Cells from the dorsal part of the developing neural tube emigrate and become neural crest cells, which in turn contribute to the development of the peripheral nervous system and a variety of non-neural structures. Other neural tube cells form the neurons and glial cells of the central nervous system (CNS). This has led to the neural crest being treated as the sole neural tube-derived emigrating cell population, with the remaining neural tube cells assumed to be restricted to forming the CNS. However, this restriction has not been tested fully. Our investigations of chick, quail and duck embryos utilizing a variety of different labelling techniques (DiI, LacZ, GFP and quail chimera) demonstrate the existence of a second neural tube-derived emigrating cell population. These cells originate from the ventral part of the cranial neural tube, emigrate at the exit/entry site of the cranial nerves, migrate in association with the nerves and populate their target tissues. On the basis of its site of origin and route of migration we have named this cell population the ventrally emigrating neural tube (VENT) cells. VENT cells also differ from neural crest cells in that they emigrate considerably after the emigration of neural crest cells, and lack expression of the neural crest cell antigen HNK-1. VENT cells are multipotent, differentiating into cell types belonging to all four basic tissues in the body: the nerve, muscle, connective and epithelium. Thus, the neural tube provides at least two cell populations--neural crest and VENT cells--that contribute to the development of the peripheral nervous system and various non-neural structures. This review describes the origin of the idea of VENT cells, and discusses evidence for their existence and subsequent fates.

  7. Submarine radial vents on Mauna Loa Volcano, Hawai'i

    USGS Publications Warehouse

    Wanless, V. Dorsey; Garcia, M.O.; Trusdell, F.A.; Rhodes, J.M.; Norman, M.D.; Weis, Dominique; Fornari, D.J.; Kurz, M.D.; Guillou, Herve

    2006-01-01

    A 2002 multibeam sonar survey of Mauna Loa's western flank revealed ten submarine radial vents and three submarine lava flows. Only one submarine radial vent was known previously. The ages of these vents are constrained by eyewitness accounts, geologic relationships, Mn-Fe coatings, and geochemical stratigraphy; they range from 128 years B.P. to possibly 47 ka. Eight of the radial vents produced degassed lavas despite eruption in water depths sufficient to inhibit sulfur degassing. These vents formed truncated cones and short lava flows. Two vents produced undegassed lavas that created “irregular” cones and longer lava flows. Compositionally and isotopically, the submarine radial vent lavas are typical of Mauna Loa lavas, except two cones that erupted alkalic lavas. He-Sr isotopes for the radial vent lavas follow Mauna Loa's evolutionary trend. The compositional and isotopic heterogeneity of these lavas indicates most had distinct parental magmas. Bathymetry and acoustic backscatter results, along with photography and sampling during four JASON2 dives, are used to produce a detailed geologic map to evaluate Mauna Loa's submarine geologic history. The new map shows that the 1877 submarine eruption was much larger than previously thought, resulting in a 10% increase for recent volcanism. Furthermore, although alkalic lavas were found at two radial vents, there is no systematic increase in alkalinity among these or other Mauna Loa lavas as expected for a dying volcano. These results refute an interpretation that Mauna Loa's volcanism is waning. The submarine radial vents and flows cover 29 km2 of seafloor and comprise a total volume of ∼2×109 m3 of lava, reinforcing the idea that submarine lava eruptions are important in the growth of oceanic island volcanoes even after they emerged above sea level.

  8. 40 CFR 63.115 - Process vent provisions-methods and procedures for process vent group determination.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... vent stream is halogenated, the mass emission rate of halogen atoms contained in organic compounds shall be calculated. (A) The vent stream concentration of each organic compound containing halogen atoms... atoms: ER22AP94.204 where: E=mass of halogen atoms, dry basis, kilogram per hour. K2 = Constant,...

  9. An experimental study on fracture mechanical behavior of rock-like materials containing two unparallel fissures under uniaxial compression

    NASA Astrophysics Data System (ADS)

    Huang, Yan-Hua; Yang, Sheng-Qi; Tian, Wen-Ling; Zeng, Wei; Yu, Li-Yuan

    2016-06-01

    Strength and deformability characteristics of rock with pre-existing fissures are governed by cracking behavior. To further research the effects of pre-existing fissures on the mechanical properties and crack coalescence process, a series of uniaxial compression tests were carried out for rock-like material with two unparallel fissures. In the present study, cement, quartz sand, and water were used to fabricate a kind of brittle rock-like material cylindrical model specimen. The mechanical properties of rock-like material specimen used in this research were all in good agreement with the brittle rock materials. Two unparallel fissures (a horizontal fissure and an inclined fissure) were created by inserting steel during molding the model specimen. Then all the pre-fissured rock-like specimens were tested under uniaxial compression by a rock mechanics servo-controlled testing system. The peak strength and Young's modulus of pre-fissured specimen all first decreased and then increased when the fissure angle increased from 0° to 75°. In order to investigate the crack initiation, propagation and coalescence process, photographic monitoring was adopted to capture images during the entire deformation process. Moreover, acoustic emission (AE) monitoring technique was also used to obtain the AE evolution characteristic of pre-fissured specimen. The relationship between axial stress, AE events, and the crack coalescence process was set up: when a new crack was initiated or a crack coalescence occurred, the corresponding axial stress dropped in the axial stress-time curve and a big AE event could be observed simultaneously. Finally, the mechanism of crack propagation under microscopic observation was discussed. These experimental results are expected to increase the understanding of the strength failure behavior and the cracking mechanism of rock containing unparallel fissures.

  10. Clinical Evaluation of the Retention of Different Pit and Fissure Sealants: A 1-Year Study

    PubMed Central

    Kumaran, Parvathy

    2013-01-01

    ABSTRACT Objective: The aim of this study was to evaluate the retention of different pit and fissure sealants on the first permanent molars over a period of one year. Materials and methods: In this study, a total of 40 children with all first permanent molars erupted received four different pit and fissure sealants. The children were evaluated at 6 and 12 months. Results: The data was subjected to Chi-square test and Kaplan Meier survival analysis. The p-value was calculated using Wilcoxon matched-pairs signed-rank test. Conclusion: The retention rates of resin-based sealants were superior to that of glass ionomer sealant. How to cite this article: Kumaran P. Clinical Evaluation of the Retention of Different Pit and Fissure Sealants: A 1-Year Study. Int J Clin Pediatr Dent 2013;6(3):183-187. PMID:25206219

  11. The economics of pit and fissure sealants in preventive dentistry: a review.

    PubMed

    Kitchens, Dinah H

    2005-08-15

    Oral diseases are progressive, cumulative, and become more intricate to treat with advancement. While dental caries is an infectious transmissible disease with children being at the highest risk, primary prevention can reduce this risk. Primary prevention in dentistry is usually considered to be community fluoridated water supplies, professional fluoride treatments, and pit and fissure sealants. While community fluoridated water supplies have been proven to be cost-effective, the cost-effectiveness of pit and fissure sealants has primarily been studied in school-based programs of children from low socio-economic backgrounds. Dental sealant programs are just one way to help increase primary prevention in the oral health disparities of children. The purpose of this paper is to review the literature regarding the cost-effectiveness of pit and fissure sealants as a preventive strategy in preventive dentistry.

  12. Bond strength and microleakage of self-adhesive and conventional fissure sealants.

    PubMed

    Simsek Derelioglu, Sera; Yilmaz, Yucel; Celik, Pelin; Carikcioglu, Burak; Keles, Sultan

    2014-01-01

    The aim of this study was to compare the shear bond strengths (SBS), failure modes (adhesive, cohesive, or mixed), and marginal microleakage occurrence of conventional resin (CR)-based, glass ionomer (GI)-based, and self-adhesive resin (SAR)-based fissure sealants with or without prior phosphoric acid (PA) etching. Fifty extracted premolars were randomly and equally assigned into five groups -G1:PA+CR, G2:PA+GI, G3:GI, G4:PA+SAR, and G5:SAR. Prior PA etching significantly (p<0.05) increased the SBSs of sealants. Adhesive failure mainly occurred in teeth treated with SAR- or GI-based fissure sealants, and cohesive failure mainly occurred in PA-etched teeth. Microleakage occurrence differed significantly (p<0.05) among the five groups of treated teeth. We concluded that conditioning of a tooth's enamel surface is crucial to creating strong bonds and leak-free sealing between tooth and fissure sealant.

  13. [Treatment of chronic anal fissures: diltiazem or isosorbide dinitrate as first choice?].

    PubMed

    Boeker, Eveline B; Kruijer, M J P Marjan; Verbeek, Paul C M

    2011-01-01

    Chronic anal fissures are a painful condition frequently seen in general practice, with an incidence of 2,5/1000 per year. According to the practice guidelines of the Dutch College of General Practitioners, isosorbide dinitrate 1% ointment (ISDN) is the treatment of first choice for chronic anal fissures. Systemic side-effects such as headache are reported in 27% of all cases. This side effect in combination with the frequent application of ISDN (4-6 times daily) leads to a low compliance for this therapy. A meta-analysis of the Cochrane Collaboration showed similar efficacy of diltiazem compared to ISDN. Diltiazem has several advantages: the application frequency is only twice daily, no systemic side-effects have been reported, the total costs of treatment are lower than the costs of ISDN and a standard preparation of diltiazem ointment is available. Therefore, diltiazem 2% ointment should be the first line treatment for chronic anal fissures.

  14. Femtosecond Laser in situ Keratomileusis Flap Creation in Narrow Palpebral Fissure Eyes without Suction.

    PubMed

    Chang, John S M; Law, Antony K P; Ng, Jack C M; Cheng, May S Y

    2017-01-01

    To evaluate a surgical technique used in eyes with narrow palpebral fissure undergoing femtosecond laser flap creation without suction during laser in situ keratomileusis (LASIK). All data of 2 patient groups were collected through chart review. Group 1 consisted of 6 eyes with narrow palpebral fissure in which the suction ring was manually fixated and femtosecond laser was applied accordingly. Thirty comparison cases were randomly drawn from among eyes that underwent a standard LASIK procedure matched for age and preoperative refraction (group 2). Only 1 eye of each patient was selected to compare the refractive and visual outcomes between groups. In all group 1 eyes, the flaps were created successfully with manual fixation of the suction ring without suction. No eyes lost 2 or more lines of vision. No significant difference was found in the safety and refractive outcomes between groups. Manual fixation of the suction ring in eyes with narrow palpebral fissure without suction was feasible for flap creation during LASIK.

  15. Deep-Sea Hydrothermal-Vent Sampler

    NASA Technical Reports Server (NTRS)

    Behar, Alberto E.; Venkateswaran, Kasthur; Matthews, Jaret B.

    2008-01-01

    An apparatus is being developed for sampling water for signs of microbial life in an ocean hydrothermal vent at a depth of as much as 6.5 km. Heretofore, evidence of microbial life in deep-sea hydrothermal vents has been elusive and difficult to validate. Because of the extreme conditions in these environments (high pressures and temperatures often in excess of 300 C), deep-sea hydrothermal- vent samplers must be robust. Because of the presumed low density of biomass of these environments, samplers must be capable of collecting water samples of significant volume. It is also essential to prevent contamination of samples by microbes entrained from surrounding waters. Prior to the development of the present apparatus, no sampling device was capable of satisfying these requirements. The apparatus (see figure) includes an intake equipped with a temperature probe, plus several other temperature probes located away from the intake. The readings from the temperature probes are utilized in conjunction with readings from flowmeters to determine the position of the intake relative to the hydrothermal plume and, thereby, to position the intake to sample directly from the plume. Because it is necessary to collect large samples of water in order to obtain sufficient microbial biomass but it is not practical to retain all the water from the samples, four filter arrays are used to concentrate the microbial biomass (which is assumed to consist of particles larger than 0.2 m) into smaller volumes. The apparatus can collect multiple samples per dive and is designed to process a total volume of 10 L of vent fluid, of which most passes through the filters, leaving a total possibly-microbe-containing sample volume of 200 mL remaining in filters. A rigid titanium nose at the intake is used for cooling the sample water before it enters a flexible inlet hose connected to a pump. As the water passes through the titanium nose, it must be cooled to a temperature that is above a mineral

  16. Diversity and distribution of microbes in deep-sea sub-vent systems, using newly designed in situ growth chambers

    NASA Astrophysics Data System (ADS)

    Higashi, Y.; Sunamura, M.; Utsumi, M.; Urabe, T.; Maruyama, A.

    2004-12-01

    Subsurface of deep-sea hydrothermal vent environments is one of the most difficult fields on the Earth to approach and collect reliable samples for microbiological study. In our Archaean Park project, we developed in situ incubation instruments to directly collect microbes from sub-vent fields through a drilled borehole. After excavation using a portable submarine driller (BMS) around deep-sea hydrothermal vents in the Suiyo Seamount on the Izu-Bonin Arc (2001, 2002) and the South Mariana (2003), microbial diversity was examined in samples collected from the boreholes, as well as natural vents, using catheter- and column-type in situ growth chambers. In the catheter samples collected from the Suiyo Seamount, several novel phylotypes of microbial SSU rRNA genes were assigned within epsilon-Proteobacteria and hyperthermophile-related Euryarchaea groups. The former novel epsilon group (SSSV-BE1) was also detected in the South Mariana, but they only appeared in the catheter samples collected just below the venting seafloor. These suggest that the group must be significant in warm, shallow and microaerobic sub-vent layers over the sea, at least in the northwest Pacific Ocean. The column-type in situ growth chamber was specially designed for creating and maintaining physico-chemical gradients in a ca. 40-cm-long column situated on an active vent. In Suiyo Seamount samples (vent temp.: ca. 30-100 degree C), a unique vertical profile was found in the diversity of Archaea. At the column bottom, most of the clones were assigned to be members within the lithoautotrophic thermophilic Ignicoccus, while heterotrophic thermophilic Thermococcus were abundant at the column top. Similar vertical profile has also been appeared in the column samples from the South Mariana. Further quantitative population analysis is now under going using these samples. Our approach to the sub-vent biosphere by the combination of drilling and in situ incubation is almost sure to give us important clues

  17. The effect of CT technical factors on quantification of lung fissure integrity

    NASA Astrophysics Data System (ADS)

    Chong, D.; Brown, M. S.; Ochs, R.; Abtin, F.; Brown, M.; Ordookhani, A.; Shaw, G.; Kim, H. J.; Gjertson, D.; Goldin, J. G.

    2009-02-01

    A new emphysema treatment uses endobronchial valves to perform lobar volume reduction. The degree of fissure completeness may predict treatment efficacy. This study investigated the behavior of a semiautomated algorithm for quantifying lung fissure integrity in CT with respect to reconstruction kernel and dose. Raw CT data was obtained for six asymptomatic patients from a high-risk population for lung cancer. The patients were scanned on either a Siemens Sensation 16 or 64, using a low-dose protocol of 120 kVp, 25 mAs. Images were reconstructed using kernels ranging from smooth to sharp (B10f, B30f, B50f, B70f). Research software was used to simulate an even lower-dose acquisition of 15 mAs, and images were generated at the same kernels resulting in 8 series per patient. The left major fissure was manually contoured axially at regular intervals, yielding 37 contours across all patients. These contours were read into an image analysis and pattern classification system which computed a Fissure Integrity Score (FIS) for each kernel and dose. FIS values were analyzed using a mixed-effects model with kernel and dose as fixed effects and patient as random effect to test for difference due to kernel and dose. Analysis revealed no difference in FIS between the smooth kernels (B10f, B30f) nor between sharp kernels (B50f, B70f), but there was a significant difference between the sharp and smooth groups (p = 0.020). There was no significant difference in FIS between the two low-dose reconstructions (p = 0.882). Using a cutoff of 90%, the number of incomplete fissures increased from 5 to 10 when the imaging protocol changed from B50f to B30f. Reconstruction kernel has a significant effect on quantification of fissure integrity in CT. This has potential implications when selecting patients for endobronchial valve therapy.

  18. Groundwater circulation between volcanic fissure systems evidenced by water stable isotopes

    NASA Astrophysics Data System (ADS)

    Sveinbjornsdottir, Arny

    2016-04-01

    The divergent boundary between the European and American plates in Iceland, generally called the Neovolcanic zone, is characterized by well defined volcanic systems, each consisting of a central volcano, fissure swarm and a high temperature hydrothermal activity. Isotopic studies within the Northern part of the Neovolcanic zone, where five NNE striking left-stepping en echelon volcanic systems have been identified indicate both a very complex groundwater inflow and geological structure of the thermal areas. The isotopic values of the thermal waters vary considerably both within and between systems. The fluids are a mixture of precipitation, either local or from far away, and older groundwater with a pre-Holocene component. Observed oxygen shift is highly variable from less than 1‰ to about 7‰. On surface the volcanic systems and fissure swarms are very distinct and well separated. Groundwater flow is mainly fissure/fracture controlled and thus assumed to be only along the fissure swarms with little or no flow connection between the volcanic systems. However recent isotopic studies have shown some evidence that at depth the thermal water can flow from one volcanic fissure system to the next. This is in accordance with recent observations of a segmented dyke intrusion in one of the volcanic system (Bárdarbunga) that grew laterally for more than 45 km at a relatively shallow depth (5-8 km) and ended in an effusive fissure eruption within the nearby Askja volcanic system (Sigmundsson et al., 2015). Isotopic data on the thermal waters within the Northern part of the Neovolcanic zone will be presented and fluid circulation within the volcanic systems constructed.

  19. Conversion degree, microhardness, microleakage and fluoride release of different fissure sealants.

    PubMed

    Kuşgöz, Adem; Tüzüner, Tamer; Ulker, Mustafa; Kemer, Bariş; Saray, Onur

    2010-11-01

    The purpose of this study was to determine the degree of conversion (DC), microhardness, microleakage and fluoride release of a nano-filled resin based fissure sealant (Grandio Seal, GS) and compare it with an un-filled resin based fissure sealant (Clinpro, CL) and a glass-ionomer based fissure sealant (Fuji Triage, FT). Disk shaped specimens were prepared from tested fissure sealants to determine the DC, Vicker hardness (VHN) and fluoride release (FR). The DC and VHN of each material was evaluated after 24 h. The cumulative fluoride concentrations were evaluated at 1 h, 6 h, 12 h, 1, 7, 15 and 30 days. For microleakage evaluation, fissure sealants were applied to the etched and dried enamel surfaces of sound third molar teeth according to the manufacturer's instructions (n=10). After the thermocycling and mechanical loading procedures, microleakage assessments were carried out. Data were analyzed using one-way ANOVA followed by a post hoc Tukey test, the Kruskal Wallis and Mann-Whitney U test (p<0.05). Results revealed differences regarding DC between all groups: FT (89%) > GS (55.02%) > CL (%51.10) (p<0.05). The VHN values were significantly different among all groups in the following order: GS > FT > CL (p<0.05). FT exhibited significantly higher microleakage scores compared to the CL and GS sealants (p<0.05). The FR of FT was significantly greater than CL and GS (p<0.05). Nano-filled resin based sealant can be used as an alternative to other fissure sealant materials because of its superior hardness results and feasible sealing ability.

  20. Medical and surgical treatment of haemorrhoids and anal fissure in Crohn's disease: a critical appraisal.

    PubMed

    D'Ugo, Stefano; Franceschilli, Luana; Cadeddu, Federica; Leccesi, Laura; Blanco, Giovanna Del Vecchio; Calabrese, Emma; Milito, Giovanni; Di Lorenzo, Nicola; Gaspari, Achille L; Sileri, Pierpaolo

    2013-03-11

    The principle to avoid surgery for haemorrhoids and/or anal fissure in Crohn's disease (CD) patients is still currently valid despite advances in medical and surgical treatments. In this study we report our prospectively recorded data on medical and surgical treatment of haemorrhoids and anal fissures in CD patients over a period of 8 years. Clinical data of patients affected by perianal disease were routinely and prospectively inserted in a database between October 2003 and October 2011 at the Department of Surgery, Tor Vergata University Hospital, Rome. We reviewed and divided in two groups records on CD patients treated either medically or surgically according to the diagnosis of haemorrhoids or anal fissures. Moreover, we compared in each group the outcome in patients with prior diagnosis of CD and in patients diagnosed with CD only after perianal main treatment. Eighty-six CD patients were included in the study; 45 were treated for haemorrhoids and 41 presented with anal fissure. Conservative approach was initially adopted for all patients; in case of medical treatment failure, the presence of stable intestinal disease made them eligible for surgery. Fifteen patients underwent haemorrhoidectomy (open 11; closed 3; stapled 1), and two rubber band ligation. Fourteen patients required surgery for anal fissure (Botox ± fissurectomy 8; LIS 6). In both groups we observed high complication rate, 41.2% for haemorrhoids and 57.1% for anal fissure. Patients who underwent haemorrhoidectomy without certain diagnosis of CD had significantly higher risk of complications. Conservative treatment of proctologic diseases in CD patients has been advocated given the high risk of complications and the evidence that spontaneous healing may also occur. From these preliminary results a role of surgery is conceivable in high selected patients, but definitve conclusions can't be made. Further randomized trials are needed to establish the efficacy of the surgical approach, giving