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Sample records for fissured formations

  1. SURFACE FISSURE FORMATION ABOVE UNDERGROUND COALSEAM FIRES: DIMENSIONLESS RELATIONSHIPS BETWEEN SURFACE FISSURES AND SUBSURFACE SUBSIDENCE

    NASA Astrophysics Data System (ADS)

    Ide, T. S.; Pollard, D. D.; Orr, F. M.

    2009-12-01

    Coalbed fires are uncontrolled subsurface fires that occur around the world. These fires are believed to be significant contributors to annual CO2 emissions. Although many of these fires have been burning for decades, researchers have only recently begun to investigate physical mechanisms that control fire behavior. One aspect that is poorly characterized is the relationship between subsurface combustion and surface fissures. At the surface above many fires, long, wide fissures are observed. At a coalbed fire near Durango, Colorado, these fissures form systematic orthogonal patterns that align with regional joints in the Upper Cretaceous Fruitland Formation. Understanding the mechanisms that form and widen these fissures is important, as the fissures are believed to play vital roles in sustaining the combustion in the subsurface by acting as chimneys for the escaping gases and conduits for incoming oxygen. In some of the coalbed fire simulation models available today, these fissures are treated as fixed boundary conditions, but we argue, using field observations and simulation results, that there exists a relationship between the location and magnitude of subsidence caused by the fire and the opening of fissures. Four distinct types of fissures are observed over the coalbed fire near Durango, CO. These fissures are termed ‘molehill’, ‘plateau’, ‘gaping’, and ‘narrow’ based on their surface appearances. Molehill fissures are marked by surface depressions on either side, causing the strata around the opening to form an apex towards the center of the fissure. Plateau fissures show a steep vertical offset on only one side with minimal horizontal displacement. Gaping fissures and narrow fissures are predominantly opening with little evidence for vertical displacements. Gaping fissures are defined as fissures with wide apertures (0.3 ~ 1.5m), while narrow fissures have apertures on the order of centimeters. A boundary element method code was used to show

  2. Giant desiccation fissures filled with calcareous eolian sand, Hermosa Formation (Pennsylvanian), southeastern Utah

    NASA Astrophysics Data System (ADS)

    Loope, David B.; Haverland, Zsolt E.

    1988-04-01

    At two stratigraphic intervals within the upper member of the Upper Pennsylvanian Hermosa Formation, calcareous eolian sand fills downward-tapering fissures that are as much as 18 cm wide and 5.7 m deep. Fissure fillings define orthogonal polygons 10 m or more in diameter. One of the host beds is primarily composed of subtidally deposited limestone, the other is a thinly laminated, nonmarine red siltstone. Both systems of fissure fillings are directly overlain and underlain by large-scale cross-stratified, calcareous eolianites. The limestone host bed contains chert pseudomorphs after gypsum. Compaction of host rocks contorted fissure fillings and caused doming of eolian strata over each fissure. Platy mineral grains in fissure fillings are aligned subparallel to bedding in the host rocks, supporting the view that the fissures were passively filled rather than forcefully injected. These ancient fissure systems are similar in scale and pattern to those that define giant desiccation polygons in numerous Great Basin playas. The Pennsylvanian fissures, like their Holocene counterparts, probably formed when groundwater tables dropped from shallow levels within fine-grained, impermeable deposits into underlying aquifers, greatly decreasing the extent of the capillary fringe. Our study of the fissures and host rocks supports the hypothesis that carbonate grains within the eolianites were deflated from uncemented marine sediments that were broadly exposed during regressive intervals.

  3. Effect of Local Crystallographic Texture on the Fissure Formation During Charpy Impact Testing of Low-Carbon Steel

    NASA Astrophysics Data System (ADS)

    Ghosh, Abhijit; Patra, Sudipta; Chatterjee, Arya; Chakrabarti, Debalay

    2016-06-01

    The severity of the formation of fissures (also known as splitting or delamination) on the fracture surface of Charpy impact-tested samples of a low-carbon steel has been found to increase with the decrease in finish rolling temperature [1093 K to 923 K (820 °C to 650 °C)]. Combined scanning electron microscopy and electron back-scattered diffraction study revealed that crystallographic texture was the prime factor responsible for the fissure formation. Through-thickness texture band composed of cube [Normal Direction (ND)║<001>] and gamma [ND║<111>] orientations developed during the inter-critical rolling treatment. Strain incompatibility between these two texture bands causes fissure cracking on the main fracture plane. A new approach based on the angle between {001} planes of neighboring crystals has been employed in order to estimate the `effective grain size,' which is used to determine the cleavage fracture stress on different planes of a sample. The severity of fissure formation was found to be directly related to the difference in cleavage fracture stress between the `main fracture plane' and `fissure plane.' Clustering of ferrite grains having cube texture promoted the fissure crack propagation along the transverse `fissure plane,' by increasing the `effective grain size' and decreasing the cleavage fracture stress on that plane.

  4. Anal fissure.

    PubMed

    Metcalf, Amanda M

    2002-12-01

    Anal fissure is a common condition with a characteristic presentation. Despite increased pharmaceutical options in the medical management of anal fissures, surgical therapy is not in danger of becoming obsolete. Lateral internal sphincterotomy remains an attractive option for many patients suffering from this painful condition. PMID:12516855

  5. 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

  6. Anal fissure

    MedlinePlus

    ... pain interferes with normal bowel movements Petroleum jelly Zinc oxide, 1% hydrocortisone cream, Preparation H, and other ... anal muscle Prescription creams such as nitrates or calcium channel blockers, applied over the fissure to help ...

  7. 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 ...

  8. Anal fissure - series (image)

    MedlinePlus

    ... rectum through which passes stool during defecation. The anal sphincter is a critical mechanism for control of ... Anal fissures are tears in the skin overlying the anal sphincter, usually due to increased tone of ...

  9. Numerical simulation of earth fissures due to groundwater withdrawal

    NASA Astrophysics Data System (ADS)

    Wang, Z.; Zhang, Y.; Wu, J.; Yu, J.; Gong, X.

    2015-11-01

    Excessive groundwater withdrawal can cause land subsidence and earth fissures. The initiation and propagation of earth fissures are related to tensile failure and crack propagation in soils. Based on fracture mechanics, the crack band model (CBM), one of the smear crack models which is relatively easy to construct and convenient to be integrated into standard finite element codes is used in this paper. The calculated results of CBM are less dependent on the sizes of finite elements. The model was applied to simulate the formation and propagation of earth fissures in the hydrostratigraphic units with a bedrock ridge. The simulated positions and patterns of earth fissures coincide with field observations, suggesting that the modeling approach is adept to simulate the initiation and propagation of earth fissures due to groundwater withdrawal.

  10. Formation of clastogenic lava flows during fissure eruption and scoria cone collapse: the 1986 eruption of Izu-Oshima Volcano, eastern Japan

    NASA Astrophysics Data System (ADS)

    Sumner, Janet M.

    The 1986 eruption of B fissure at Izu-Oshima Volcano, Japan, produced, among other products, one andesite and two basaltic andesite lava flows. Locally the three flows resemble vent-effused holocrystalline blocky or aa lava; however, remnant clast outlines can be identified at most localities, indicating that the flows were spatter fed or clastogenic. The basaltic andesite flows are interpreted to have formed by two main processes: (a) reconstitution of fountain-generated spatter around vent areas by syn-depositional agglutination and coalescence, followed by extensional non-particulate flow, and (b) syn-eruptive collapse of a rapidly built spatter and scoria cone by rotational slip and extensional sliding. These processes produced two morphologically distinct lobes in both flows by: (a) earlier non-particulate flow of agglutinate and coalesced spatter, which formed a thin lobe of rubbly aa lava (ca. 5 m thick) with characteristic open extension cracks revealing a homogeneous, holocrystalline interior, and (b) later scoria-cone collapse, which created a larger lobe of irregular thickness (<20 m) made of large detached blocks of scoria cone interpreted to have been rafted along on a flow of coalesced spatter. The source regions of these lava flows are characterized by horseshoe-shaped scarps (<30 m high), with meso-blocks (ca. 30 m in diameter) of bedded scoria at the base. One lava flow has a secondary lateral collapse zone with lower (ca. 7 m) scarps. Backward-tilted meso-blocks are interpreted to be the product of rotational slip, and forward-tilted blocks the result of simple toppling. Squeeze-ups of coalesced spatter along the leading edge of the meso-blocks indicate that coalescence occurred in the basal part of the scoria cone. This low-viscosity, coalesced spatter acted as a lubricating layer along which basal failure of the scoria cone occurred. Rotational sliding gave way to extensional translational sliding as the slide mass spread out onto the present

  11. Study of the deformation mechanism of the Gaoliying ground fissure

    NASA Astrophysics Data System (ADS)

    Cheng, G.; Wang, H.; Luo, Y.; Guo, H.

    2015-11-01

    The Gaoliying ground fissure in Beijing has caused building cracking and road damage, and has seriously influenced city construction. Based on investigations and trenching, the influences of the fault and the variation of groundwater levels on the formation mechanism of the Gaoliying ground fissure were investigated by using FLAC3D. The results indicated that (1) the surface location of Gaoliying fissure is controlled by the underlying normal fault activity, and over pumping further exacerbates development of the ground fissure; (2) when the groundwater level declines, obvious differential settlement occurs at both sides of the ground fissure, in which greater settlement occurs in the vicinity of the hanging wall, the greater the distance from the hanging wall, the smaller the ground subsidence, however smaller ground subsidence occurs in the vicinity of the footwall, the greater the distance from the footwall, the greater the ground subsidence; (3) the vertical velocity of the ground fissure triggered by the fault activity and groundwater decline ranges from 15.5 to 18.3 mm a-1, which is basically in line with the monitoring data. The fault activity contributes about 28-39 %, and the groundwater contributes about 61-72 % to the deformation of the ground fissure, respectively.

  12. 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

  13. 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.

  14. Fluoride release from fissure sealants.

    PubMed

    Garcia-Godoy, F; Abarzua, I; De Goes, M F; Chan, D C

    1997-01-01

    This 30-day study, compared the amounts and patterns of fluoride release from 5 commercially available fluoride-containing pit and fissure sealants: FluroShield, Helioseal-F, Ultraseal XT, Baritone L3, and Teethmate-F; Delton without fluoride, was used as control. Disc-shaped samples of each sealant were immersed in distilled water and the fluoride release was measured periodically until day 30. All the fluoridated sealants tested released measurable fluoride throughout the test period in a similar pattern: the greatest amount of fluoride was released in the first 24 hours after mixing, fell sharply on the second day and decreased slowly for the last days. On day one, Baritone L3 released significantly more fluoride than all other materials. Teethmate-F released the highest amount of fluoride during all the other time intervals from day 2, until day 30. PMID:9643204

  15. 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.

  16. 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. PMID:24742084

  17. Narrow Vertical Caves: Mapping Volcanic Fissure Geometries

    NASA Astrophysics Data System (ADS)

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

    2015-10-01

    Volcanic conduits are difficult to quantify, but their geometry fundamentally influences how eruptions occur. We robotically map old fissure conduits - elongated narrow cracks in the ground that transported magma to the surface during an eruption.

  18. 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.

  19. Outpatient treatment of fissure-in-ano.

    PubMed

    Badejo, O A

    1984-12-01

    A review of 86 cases of fissure-in-ano as seen in Ife is presented. The method of management is described and compared with other conservative methods of treatment. The results show a complete healing of the condition within two weeks as compared with four to six weeks recorded in other series. Healing was confirmed by a complete resolution of symptoms together with re-epithelisation of the fissure on inspection at proctoscopy. It is suggested that the described surgical management is simple, fast, cost reducing and time saving in the treatment of fissure-in-ano. It is further envisaged that this procedure may also serve as a means of relief to our already congested hospitals. PMID:6528355

  20. Effect of surface fissure on apparent resistivity measurements

    NASA Astrophysics Data System (ADS)

    Sailhac, P.; Gance, J.; Malet, J.

    2013-12-01

    Fissures are features of interest, prone to create preferential flow path, modifying locally the soil hydrogeological behavior. Electrical Resistivity Tomography (ERT) is a suitable tool to monitor such preferential flow path. However, this technique is not efficient in the presence of surface fissure, due to a bad resistivity recovering around the fissure vicinity during the inversion process. Therefore, we propose a description of fissure effect on raw apparent resistivity on three resistivity arrays. The purposes of the study are multiple. First, we aim at making ERT users aware of surface fissure effect, and propose a first help to interpret basically resistivity pseudo sections. Second, we propose to ERT users to automatically conduct a surface fissure survey on the studied profile, in order to consider each fissure in a forward DC model and to suppress their effect. Finally, this study is only a first step toward 2D fissure shape inversion, and time-lapse monitoring of fissure drying and filling. In this study, we create a fissure model based on different geomorphological descriptors. After describing the FEM-DC forward modeling strategy, we investigate the fissure effect on pseudo section of apparent resistivity for a Wenner-Schlumberger (WS), a dipole-dipole (DD) and a gradient (GRAD) array. We determine a fissure detectability threshold for each array and perform a sensitivity analysis on the different fissure parameters (position, width, depth, dip angles...). The crack filling or drying effect is also investigated. The possibility to remove fissure effect and to propose a first interpretation of time-lapse data is illustrated on real data. This study show again the higher sensitivity of the DD array compared to the GRAD and WS arrays. Not only the maximal amplitude in the pseudo section is higher for the DD array, but also the anomaly pattern created by the fissure is much larger for this acquisition geometry. The minimal depth detectable for the DD

  1. Thoracoscopic sympathetic clamping in a patient with an azygos fissure.

    PubMed

    Moon, Seok Whan; Yoon, Jeong Sub; Jo, Keon Hyeon; Wang, Young Pil; Park, Hyeon Jin

    2005-04-01

    We believe that an azygos fissure may predispose to bleeding during thoracoscopic surgery. An azygos fissure causes important morphologic changes in the superior mediastinum and thereby poses a risk of massive bleeding during thoracoscopic procedures. We report on a successful thoracoscopic procedure conducted in a patient with palmar hyperhidrosis and an azygos fissure and emphasize that the course of the thoracic sympathetic chain runs laterally along the base of the azygos fissure. PMID:15821627

  2. Double-porosity models for a fissured groundwater reservoir with fracture skin.

    USGS Publications Warehouse

    Moench, A.F.

    1984-01-01

    Theories of flow to a well in a double-porosity groundwater reservoir are modified to incorporate effects of a thin layer of low-permeability material or fracture skin that may be present at fracture-block interfaces as a result of mineral deposition or alteration. The commonly used theory for flow in double-porosity formations that is based upon the assumption of pseudo-steady state block-to-fissure flow is shown to be a special case of the theory presented in this paper. The latter is based on the assumption of transient block-to-fissure flow with fracture skin.-from Author

  3. Tensions and Fissures: The Politics of Standardised Testing and Accountability in Ontario, 1995-2015

    ERIC Educational Resources Information Center

    Pinto, Laura Elizabeth

    2016-01-01

    While Ontario has received international accolades for its enactment of province-wide standardised testing upon the formation of the Education Quality and Accountability Office (EQAO), a closer look at provincial assessments over a 20-year span reveals successes as well as systemic tensions and fissures. The purpose of this paper is twofold.…

  4. From fissure to fault: A model of fault growth in the Krafla Fissure System, NE Iceland

    NASA Astrophysics Data System (ADS)

    Bramham, Emma; Paton, Douglas; Wright, Tim

    2015-04-01

    Current models of fault growth examine the relationship of fault length (L) to vertical displacement (D) where the faults exhibit the classic fault shape of gradually increasing vertical displacement from zero at the fault tips to a maximum displacement (Dmax) at the middle of the fault. These models cannot adequately explain displacement-length observations at the Krafla fissure swarm, in Iceland's northern volcanic zone, where we observe that many of the faults with significant vertical displacements still retain fissure-like features, with no vertical displacement, along portions of their lengths. We have created a high resolution digital elevation model (DEM) of the Krafla region using airborne LiDAR and measured the displacement/length profiles of 775 faults, with lengths ranging from 10s to 1000s of metres. We have categorised the faults based on the proportion of the profile that was still fissure-like. Fully-developed faults (no fissure-like regions) were further grouped into those with profiles that had a flat-top geometry (i.e. significant proportion of fault length with constant throw), those with a bell-shaped throw profile and those that show regions of fault linkage. We suggest that a fault can most easily accommodate stress by displacing regions that are still fissure-like, and that a fault would be more likely to accommodate stress by linkage once it has reached the maximum displacement for its fault length. Our results demonstrate that there is a pattern of growth from fissure to fault in the Dmax/L ratio of the categorised faults and propose a model for this growth. These data better constrain our understanding of how fissures develop into faults but also provide insights into the discrepancy in D/L profiles from a typical bell-shaped distribution.

  5. Influence of matrix diffusion and exchange reactions on radiocarbon ages in fissured carbonate aquifers

    SciTech Connect

    Maloszewski, P. ); Zuber, A. )

    1991-08-01

    The parallel fissure model coupled with the equation of diffusion into the matrix and with exchange reaction equations has been used to derive a simple formula for estimating the influence of matrix porosity and reaction parameters on the determination of radiocarbon ages in fissured carbonate rocks. Examples of evidently too great radiocarbon ages in carbonate formations, which are not explainable by models for the initial {sup 14}C corrections, can easily be explained by this formula. Parameters obtained for a chalk formation from a known multitracer experiment combined with a pumping test suggest a possibility of {sup 14}C ages more than three orders of magnitude greater than the ages which would be observed if the radiocarbon transport took place only in the mobile water in the fissures. It is shown that contrary to the solute movement on a small scale and with a variable input, the large-scale movement, characteristic for the {sup 14}C dating, does not necessarily require the knowledge of kinetic parameters, because they may be replaced by the distribution coefficient. Discordant tritium and {sup 14}C concentrations are commonly interpreted as a proof of mixing either in the aquifer or at the discharge site. For fissured carbonate formations, however, an alternative explanation is given by the derived model showing a considerable delay of {sup 14}C with respect to nonsorbable tracers.

  6. 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. PMID:26274986

  7. Visualization of three dimensional earth fissures in geological structure

    NASA Astrophysics Data System (ADS)

    Zhu, L.; Yu, J.; Liu, Y.; Gong, H.; Chen, Y.; Chen, B.

    2015-11-01

    This paper proposes a new method for visualizing the earth fissures of geological structure in three dimensional (3-D) domains on the basis of the seismic data and features information of earth fissures. The seismic data were interpreted for obtaining the stratagraphic data with various lithological information and the depth of the earth fissures. The spatial distribution of the ground fissures including the dip, strike and width were digitalized on an ArcGIS platform. Firstly, the 3-D geological structure was rebuilt using the Generalized Tri-Prism (GTP) method which is a real solid method for displaying geological structures. The GTP method can reflect the inner material of the strata and can simulate complicated geological structures such as faults and stratagraphic pinch outs. The upper and lower surfaces of each stratum consist of Triangle Irregular Networks (TIN). The inner solid between the two surfaces are a series of triangular prisms. Secondly, since the width of the ground fissure gradually decreases with depth, multiple edge lines of the earth fissures on the bottom stratum surface are deduced on the basis of the fissure characteristics. Then, the model of the earth fissures consisting of a series of triangular pyramids can be constructed using these points and the edge lines. A cutting operation was carried out on the 3-D geological structure using this ground fissures model. If the surfaces of the ground fissures model intersects with the GTPs in the geological structure model, new GTPs were generated within the local regions. During this process, the topological relations between TIN, triangular prism and lines were reconstructed so that the visualization of ground fissures in the geological structure model is realized. This method can facilitate the mechanism for studying fissures and avoid the gaps between the fissure solid and the geological structure to accurately reflect their 3-D characteristics.

  8. [Fissures in biliary calculi. Personal contribution (author's transl)].

    PubMed

    Nano, M; Potenzoni, F; Camandona, M; Casalegno, P A

    1979-04-01

    In a series of 70 patients suffering from biliary lithiasis, the roentgenologic findings of fissures in the calculi was observed in 5 cases examined by means of cholecystography and in 7 cases who underwent cholangiocholecystography. Fissures were demonstrated 11 times in calculi after surgery. The "Mercedes-Benz" sign was never observed at the abdominal examination without contrast medium. The presence of fissures may be an additional sign in the radiologic diagnosis of biliary calculi, but its value is not determinant. PMID:550199

  9. [Sylvius (1614-1672) and his fissure].

    PubMed

    van Gijn, Jan; Gijselhart, Joost P

    2010-01-01

    Franciscus dele Boë, or Sylvius, was born into a family of French Huguenots who had moved to the province of Hessen. He studied medicine in Sedan, Leiden and Basle. He was a private teacher in anatomy in Leiden for some years, and while teaching he drew the attention of his students to the long fissure on either side of the cerebral surface. He practised successfully as a physician in Amsterdam from 1641 onwards, until he was recalled to the chair of medicine in Leiden in 1658. He emphasized the role of chemical processes in the human body (iatrochemistry). PMID:20699035

  10. Corrections of surface fissure effect on apparent resistivity measurements

    NASA Astrophysics Data System (ADS)

    Gance, J.; Sailhac, P.; Malet, J.-P.

    2015-02-01

    Electrical resistivity tomography (ERT) is a useful tool to detect and track water flow paths in the subsoil. However, measurements are strongly affected by subsurface heterogeneities such as fissures of different sizes and genesis (shrinking-swelling, macropores and deformation). In this work, we focus on surface fissures characterized by dimensions lower than the interelectrode spacing and correct their effect on apparent resistivity pseudo-sections by incorporating fissure geometry in the topography. We show that fissures with depths greater than 0.10 times the interelectrode spacing for a dipole-dipole array and equal to 0.16 for the gradient array and the Wenner-Schlumberger arrays create significant anomalies (greater than 5 per cent) in the pseudo-section. Surface fissure widths and dip angles have little effect with respect to the fissure depths which can increase the apparent resistivity up to 200 per cent. The clogging of the fissures with water or soil material decreases the anomaly effect linearly with the percentage of filling. The correction of apparent resistivity values is possible for relatively simple fissure geometries and only requires a manual survey of the surface fissures. It allows to improve the quality of the inverted resistivity section by mitigating the inversion artefacts and therefore a better interpretation.

  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. Fine Mapping and Introgressing a Fissure Resistance Locus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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. Pearl in interhemispheric fissure: A rare phenomenon.

    PubMed

    Agarwal, Vivek; Vijayan, Abhishek; Velho, Vernon; Mally, Rahul

    2012-10-01

    Epidermoid cysts (Keratin pearls) are benign congenital lesions, found commonly in cerebello-pontine angle, suprasellar cistern, sylvian cistern, pineal region, but they are very rare in interhemispheric fissure. Approaching these lesions are challenging to neurosurgeons because of narrow and deep fissure with surrounding vital structures. The present study constitutes an analysis of interhemispheric epidermoid managed at our hospital in last 10 years (Jan 2001-Dec 2010). Total 187 cases of intracranial epidermoid operated in our institute; eight of them were interhemispheric epidermoid making about 4.27% of all epidermoids. The patients were presented with seizures (50%), headache (37%), and weakness (25%). On examination, the common findings were decreased Mini mental score (MMSE) in 50%, motor deficit in 25%, and decreased visual acuity in 25% of cases. All patients underwent craniotomy across the midline as per the location of the lesions. In seven patients, tumors were resected by interhemispheric approach but in one by transcortical. Lesion were excised with microscope and endoscopic assistance with measures to prevent spillage of epidermoid tissue while excision. Post excision tumor bed was irrigated with hydrocortisone diluted saline. All patients except one improved after surgery and non-developed chemical meningitis. One patient of parietal interhemispheric epidermoid with transcortical approach developed weakness in immediate post-operative period. Patients were followed for average 6.8 year without any recurrence. Interhemispheric epidermoids are rare tumors. Achieving safe complete excision without spillage is surgical goal to prevent chemical meningitis and recurrence. Endoscope assists in achieving complete excision so decrease incidence of chemical meningitis and recurrence. PMID:23559996

  14. King's Bowl Pit Crater, Lava Field and Eruptive Fissure, Idaho - A Multipurpose Volcanic Planetary Analog

    NASA Astrophysics Data System (ADS)

    Hughes, S. S.; Garry, B.; Kobs-Nawotniak, S. E.; Sears, D. W. G.; Borg, C.; Elphic, R. C.; Haberle, C. W.; Kobayashi, L.; Lim, D. S. S.; Sears, H.; Skok, J. R.; Heldmann, J. L.

    2014-12-01

    King's Bowl (KB) and its associated eruptive fissure and lava field on the eastern Snake River Plain, is being investigated by the NASA SSERVI FINESSE (Field Investigations to Enable Solar System Science and Exploration) team as a planetary analog to similar pits on the Moon, Mars and Vesta. The 2,220 ± 100 BP basaltic eruption in Craters of the Moon National Monument and Preserve represents early stages of low shield growth, which was aborted when magma supply was cut off. Compared to mature shields, KB is miniscule, with ~0.02 km3 of lava over ~3 km2, yet the ~6 km long series of fissures, cracks and pits are well-preserved for analog studies of volcanic processes. The termination of eruption was likely related to proximity of the 2,270 ± 50 BP eruption of the much larger Wapi lava field (~5.5 km3 over 325 km2 area) on the same rift. Our investigation extends early work by R. Greeley and colleagues, focusing on imagery, compositional variations, ejecta distribution, dGPS profiles and LiDAR scans of features related to: (1) fissure eruptions - spatter ramparts, cones, feeder dikes, extension cracks; (2) lava lake formation - surface morphology, squeeze-ups, slab pahoehoe lava mounds, lava drain-back, flow lobe overlaps; and (3) phreatic steam blasts - explosion pits, ejecta blankets of ash and blocks. Preliminary results indicate multiple fissure eruptions and growth of a basin-filled lava lake up to ~ 10 m thick with outflow sheet lava flows. Remnant mounds of original lake crust reveal an early high lava lake level, which subsided as much as 5 m as the molten interior drained back into the fissure system. Rapid loss of magma supply led to the collapse of fissure walls allowing groundwater influx that triggered multiple steam blasts along at least 500 m. Early blasts occurred while lake magma pressure was still high enough to produce squeeze-ups when penetrated by ejecta blocks. The King's Bowl pit crater exemplifies processes of a small, but highly energetic

  15. Calcified gallstone fissures: the reversed Mercedes Benz sign.

    PubMed

    Strijk, S P

    1987-01-01

    This article describes the occurrence of an unusual radiating pattern of calcification in the center of large radiolucent gallstones. The radiographic findings are attributed to calcium deposition within the fissures of biliary calculi. PMID:3556975

  16. 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

  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. Predominant cultivable microflora of human dental fissure plaque.

    PubMed Central

    Theilade, E; Fejerskov, O; Karring, T; Theilade, J

    1982-01-01

    Plaque developed in 10 occlusal fissures from unerupted third molars during implantation for 200 to 270 days in lower molars of dental students was studied. To characterize the predominant cultivable flora, 592 isolates (51 to 67 from each fissure) were subcultured from anaerobic roll tubes. Twenty-eight of the isolates were lost. Streptococci constituted 8 to 86% (median, 45%) of the isolates, Streptococcus mutans constituted 0 to 86% (median, 25%) and S. sanguis constituted 0 to 15% (median, 1%). A few isolates of "S. mitior" and "S. milleri" were found, but no S. salivarius. Staphylococci made up 0 to 23% (median, 9%). Gram-positive rods constituted 6 to 59% (median, 35%). Of these, 0 to 46% (median, 18%) were Actinomyces naeslundii and A. viscosus, but no anaerobic actinomyces were isolated. Arachnia and propionibacteria made up small proportions, lactobacilli were isolated from two fissures, constituting 10 and 29%, and eubacteria were isolated from one fissure (27%). Gram-negative cocci made up 0 to 46% (media, 4%). Only two isolates of gram-negative rods were found, both facultative anaerobes. Although 8 of the 10 fissures had large proportions of S. mutans, lactobacilli, or both, no caries was found even with microradiography. The large individual variation probably reflects differences in initial colonization from saliva and in growth conditions in each fissure. PMID:7095858

  19. Potential for aquifer compaction, land subsidence, and earth fissures in the Tucson basin, Pima County, Arizona

    USGS Publications Warehouse

    Anderson, S.R.

    1987-01-01

    In 1979 the U.S. Geological Survey, in cooperation with the city of Tucson, began an investigation of aquifer compaction and its effects in the Tucson basin, including the potential hazards of aquifer compaction and subsequent damage to engineered structures, roads, water supply systems, gaslines, and sewage systems. Groundwater is the main source of water for irrigation, public supply, and industry. Pumping has exceeded recharge for several decades, and declines in groundwater levels have occurred in parts of the basin. In places, water level declines have resulted in small amounts of aquifer compaction and land subsidence. Further water level declines in parts of the Tucson basin may result in large amounts of aquifer compaction and land subsidence. Differential land subsidence may, in places, be accompanied by the formation of earth fissures. Aquifer compaction, land subsidence, and earth fissures can damage or affect the functional capability of manmade features. Specifically, aquifer compaction may damage wells, fissures may damage engineered structures, and differential land subsidence may affect structures such as sewers and water-supply systems that are dependent on gravity for their operation. (USGS)

  20. 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

  1. 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.

  2. Research on positioning of Xi'an ground fissures with InSAR quality map

    NASA Astrophysics Data System (ADS)

    Xu, Li; Zhao, Chao-ying

    2011-02-01

    Xi'an ground fissure is a typical geo-hazard with nearly half a century history, which have been caused serious damages to roads, building and other civil facilities. Based on the theory of deformation de-correlation of the active ground fissures, this manuscript mainly investigated the positioning method of active ground fissures by analyzing the pseudo-coherence map of adaptively filtered differential interferogram. We took two ERS1 SAR data during 1992-1993 as an example to investigate the active fissures position during this period. Consequently, high consistency between newly detected fissures and the ground fissure map from engineering geological investigation can be achieved.

  3. 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. PMID:24867398

  4. Perioperative Identification of an Accessory Fissure of the Right Lung

    PubMed Central

    Taverne, Yannick; Kleinrensink, Gert-Jan; de Rooij, Peter

    2015-01-01

    Anatomical variations of lungs are common in clinical practice; however, they are sometimes overlooked in routine imaging. Surgical anatomy of the lung is complex and many variations are known to occur. A defective pulmonary development gives rise to variations in lobes and fissures. Morphological presentation is of clinical importance and profound knowledge of the organogenesis and functional anatomy is imperative for the interpretation and evaluation of lung pathophysiology and subsequent surgical intervention. However, appreciating them on radiographs and CT scans is difficult and they are therefore often either not identified or completely misinterpreted. As presented in this case report, an accessory fissure separating the superior segment of the right lower lobe from its native lobe was seen perioperatively and could only retrospectively be defined on X-rays and CT scan. It is imperative to keep in mind that accessory fissures can be missed on imaging studies and thus can make the surgical procedure more challenging. PMID:26185701

  5. 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

  6. Pit and fissure sealant: review of the literature.

    PubMed

    Simonsen, Richard J

    2002-01-01

    For this literature review of pit and fissure sealant, 1,465 references were selected by a search for "sealants" on PubMed. References were limited to dental journals and papers in the English language. The search comprised papers from 1971 to October 2001. Additional papers of historical significance prior to 1971 were added from memory and from reference lists published in early papers. This paper reviewed the literature on pit and fissure sealants under the following subheadings: (1) laboratory studies, (2) clinical technique and tooth preparation, (3) etching time, (4) auxiliary application of pit and fissure sealant, (5) retention and caries prevention, (6) fluoride used with sealants and fluoride-containing sealant, (7) glass ionomer materials as sealants, (8) options in sealant: filled vs unfilled; colored vs clear; autocure vs light-initiated, (9) sealant placed over caries in a therapeutic manner, (10) cost effectiveness of sealant application, (11) underuse of pit and fissure sealant, (12) the estrogenicity issue, (13) use of an intermediate bonding layer to improve retention, (14) new developments and projections, and (15) summary and conclusions. From a careful and thorough review of peer-reviewed publications on pit and fissure sealant, it is clear that sealants are safe, effective and underused (at least underused in the United States). Pit and fissure sealant is best applied to high-risk populations by trained auxiliaries using sealant that incorporates the benefit of an intermediate bonding layer, applied under the rubber dam or with some alternative short-term, but effective, isolation technique, onto an enamel surface that has been cleaned with an air polishing technique and etched with 35% phosphoric acid for 15 seconds. The dental profession awaits with enthusiasm, and some impatience, the incorporation of dentin-bonding technology into the development of a modern, more durable, resin-based sealant. PMID:12412954

  7. An opening magmatic fissure: structural pattern of its termination

    NASA Astrophysics Data System (ADS)

    Zelenin, Egor A.; Kozhurin, Andrey I.; Pinegina, Tatiana K.; Mikhaylyukova, Polina G.

    2014-05-01

    Volcanic zones of Kamchatka bear two types of active faults and fractures. Faults of the first type are tectonic, so they are long-living with net offset growing with time by repeating movement. Faults of the second type could be termed volcano-tectonic as they couple with or are caused by eruptions and thus move just once. Authors have explored and described a NE-SW-striking fissure on the SW side of Gorely plateau in the South Kamchatka volcanic zone, which conducted magma 200 years ago (Selyangin, Ponomareva, 1999). The fissure depression is filled with basaltic-andesite lava. The 900 meters long southern terminus of the fissure is situated on the hill slope and therefore not overlapped with lava. The fissure ending is an asymmetric graben, deeper at its west side, up to 300 m wide and bounded by two nearly parallel normal faults. The graben floor is gradually deepening to the north, away from the terminus, down to 9-10 m. Bounding faults are perfectly expressed in topography, thus providing a rare opportunity for determination of fissure parameters. Both faults dip at 80-85°, that gives approximately up to 3 m of perpendicular extension and the same thickness of the dyke beneath. Vertical movements on the western and eastern bounding faults were accompanied by horizontal components, left-lateral and right-lateral, respectively. There are also several transverse north-facing scarps breaking the graben floor and not extending beyond its limits. The observed deformations altogether suggests simultaneous sinking of the graben floor and northward compensating movement of masses into the graben. Tectonic landforms we studied illustrate how strain could be compensated at the end of an opening fissure and provide some insight into similar settings at a regional and even global scale.

  8. 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

  9. 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)

  10. 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. PMID:26446683

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  12. Numerical modeling of the evolution of two-phase zone under fissured caprock

    SciTech Connect

    Yano, Y.; Ishido, T.

    1993-01-28

    A vapor-dominated two-phase zone would be formed in a geothermal reservoir under fissured caprock, if the permeability of the fissure is much smaller than a critical permeability which is estimated by an energy balance. If the permeability of the fissure is large, then the rule of minimum mass input would be applied.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  14. Double-Porosity Models for a Fissured Groundwater Reservoir With Fracture Skin

    NASA Astrophysics Data System (ADS)

    Moench, Allen F.

    1984-07-01

    Theories of flow to a well in a double-porosity groundwater reservoir are modified to incorporate effects of a thin layer of low-permeability material or fracture skin that may be present at fracture-block interfaces as a result of mineral deposition or alteration. The commonly used theory for flow in double- porosity formations that is based upon the assumption of pseudo-steady state block-to-fissure flow is shown to be a special case of the theory presented in this paper. The latter is based on the assumption of transient block-to-fissure flow with fracture skin. Under conditions where fracture skin has a hydraulic conductivity that is less than that of the matrix rock, it may be assumed to impede the interchange of fluid between the fissures and blocks. Resistance to flow at fracture-block interfaces tends to reduce spatial variation of hydraulic head gradients within the blocks. This provides theoretical justification for neglecting the divergence of flow in the blocks as required by the pseudo-steady state flow model. Coupled boundary value problems for flow to a well discharging at a constant rate were solved in the Laplace domain. Both slab-shaped and sphere-shaped blocks were considered, as were effects of well bore storage and well bore skin. Results obtained by numerical inversion were used to construct dimensionless-type curves that were applied to well test data, for a pumped well and for an observation well, from the fractured volcanic rock terrane of the Nevada Test Site.

  15. A Computational Geometry Approach to Automated Pulmonary Fissure Segmentation in CT Examinations

    PubMed Central

    Pu, Jiantao; Leader, Joseph K; Zheng, Bin; Knollmann, Friedrich; Fuhrman, Carl; Sciurba, Frank C; Gur, David

    2010-01-01

    Identification of pulmonary fissures, which form the boundaries between the lobes in the lungs, may be useful during clinical interpretation of CT examinations to assess the early presence and characterization of manifestation of several lung diseases. Motivated by the unique nature of the surface shape of pulmonary fissures in three-dimensional space, we developed a new automated scheme using computational geometry methods to detect and segment fissures depicted on CT images. After a geometric modeling of the lung volume using the Marching Cube Algorithm, Laplacian smoothing is applied iteratively to enhance pulmonary fissures by depressing non-fissure structures while smoothing the surfaces of lung fissures. Next, an Extended Gaussian Image based procedure is used to locate the fissures in a statistical manner that approximates the fissures using a set of plane “patches.” This approach has several advantages such as independence of anatomic knowledge of the lung structure except the surface shape of fissures, limited sensitivity to other lung structures, and ease of implementation. The scheme performance was evaluated by two experienced thoracic radiologists using a set of 100 images (slices) randomly selected from 10 screening CT examinations. In this preliminary evaluation 98.7% and 94.9% of scheme segmented fissure voxels are within 2 mm of the fissures marked independently by two radiologists in the testing image dataset. Using the scheme detected fissures as reference, 89.4% and 90.1% of manually marked fissure points have distance ≤ 2 mm to the reference suggesting a possible under-segmentation of the scheme. The case-based RMS (root-mean-square) distances (“errors”) between our scheme and the radiologist ranged from 1.48±0.92 to 2.04±3.88 mm. The discrepancy of fissure detection results between the automated scheme and either radiologist is smaller in this dataset than the inter-reader variability. PMID:19272987

  16. 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

  17. Short communication: sclerosing meningioma in the deep sylvian fissure.

    PubMed

    Fukushima, Shintaro; Narita, Yoshitaka; Yonezawa, Motoki; Ohno, Makoto; Arita, Hideyuki; Miyakita, Yasuji; Ichimura, Koichi; Yoshida, Akihiko; Shibui, Soichiro

    2014-10-01

    Sclerosing meningioma is a rare type of meningeal tumor with extensive collagen depositions. Deep sylvian meningioma, a tumor that is unattached to the dura mater, is also unusual. The biological activity of both is controversial, as are therapeutic strategies. A heterogeneous contrast-enhanced mass in the right sylvian fissure of a 10-year-old boy with a 3-year history of epilepsy was identified via magnetic resonance imaging. The patient underwent partial surgical resection because the tumor was hard and contained numerous perforators arising from the right middle cerebral artery. The tumor was histologically diagnosed as sclerosing meningioma. Twelve months after surgery, the patient was asymptomatic and did not require any additional therapies. This case is the first report of a sclerosing meningioma arising in the deep sylvian fissure. We discuss the therapeutic dilemma of this case with respect to the current literature. PMID:24141724

  18. [Aortic intramural hematoma fissuration: atypical presentation in an aircraft pilot].

    PubMed

    Fozzato, Francesca; Prioli, Maria Antonia; Santini, Francesco; Menini, Fabio; Pavan, Michela; Guarise, Paola; Vassanelli, Corrado

    2010-02-01

    Aortic intramural hematoma is a life-threatening thoracic aortic pathology. In this report we describe a case of fissuration of an aortic intramural hematoma with atypical clinical presentation, which occurred in an aircraft pilot. The patient was admitted to our emergency room with transient chest pain developed during a flight landing, followed only by persistent abdominal pain. The ECG and cardiac enzymes were normal. A portable two-dimensional transthoracic echocardiogram showed aortic root dilation and pericardial effusion. Transesophageal echocardiography showed aortic intramural hematoma with fissuration into the pericardial space. The angio-computed tomography confirmed the diagnosis. Two hours after admission the patient, with signs of cardiac tamponade, underwent Bentall surgical intervention without complications. PMID:20408481

  19. Fissuration en relaxation des aciers inoxydables austénitiques au voisinage des soudures

    NASA Astrophysics Data System (ADS)

    Auzoux, Q.; Allais, L.; Gourgues, A. F.; Pineau, A.

    2003-03-01

    Des fissures intergranulaires peuvent se développer au voisinage des soudures des aciers inoxydables austénitiques lorsqu'ils sont réchauffés dans le domaine de température compris entre 500^{circ}C et 700^{circ}C. A ces températures, les contraintes résiduelles post-soudage se relaxent par déformation viscoplastique. Il peut arriver que ces zones proches de la soudure soient tellement fragiles, qu'elles ne puissent accommoder cette faible déformation. Afin de préciser quelles peuvent être les modifications microstructurales qui conduisent à une telle fragilisation, on a examiné les microstructures de ces zones et révélé ainsi un écrouissage résiduel, responsable d'une forte élévation de la dureté. On a pu reproduire par hypertrempe puis laminage entre 400^{circ}C et 600^{circ}C une microstructure similaire. Des essais mécaniques (traction, fluage, relaxation, sur éprouvettes lisses et pré-fissurées) ont été réalisés à 550^{circ}C et à 600^{circ}C sur ces zones affectées simulées et sur un état de référence hypertrempé. Ils ont montré que l'écrouissage diminuait la ductilité dans le domaine de rupture intergranulaire, sans modifier qualitativement le mécanisme d'endommagement. Pendant la pré-déformation les incompatibilités de déformation entre grains conduiraient à l'existence de contraintes locales élevées qui favoriseraient la germination des cavités intergranulaires.

  20. Interaction between central volcanoes and fissure swarms along divergent plate boundaries: an example from Askja Volcano, Northern Iceland.

    NASA Astrophysics Data System (ADS)

    Trippanera, Daniele; Ruch, Joel; Acocella, Valerio; Urbani, Stefano; Thordarson, Thor

    2016-04-01

    Central volcanoes located along divergent plate boundaries are typically part of a larger volcanic system that consists of a central edifice and a fissure swarm through which magma propagates and spreads plates apart. Regional normal faults and graben structures develop within the volcanic system, also dissecting portions of the central volcano with ring-faults faults and eruptive fissures related to the caldera structure. Both the fissure swarm and the caldera structure influence the pathway of the ascending magma, however, the influences of the structures on magma propagation and vice versa are not well defined and understood. Here we aim to understand the relationship between the activity of the central volcano structures (e.g. caldera ring faults, radial dykes and cone sheets) and those of the fissure swarm (e.g. regional normal faults, regional dikes). We focus on Askja volcano, located in the Northern Volcanic Zone of Iceland. It is comprised of three nested calderas, largely filled in with subaerial basaltic lava flows and surrounded by a massive hyaloclastite mountain on the Eastern side. Formation of the youngest, the Öskjuvatn caldera, was initiated during the 1874-1876 rifting episode on the Askja system. This major event was followed by several localized radial and circumferential magmatic intrusions taking place along the new-formed caldera ring fault, as well as intruding in the fissure swarm related to the regional tectonics. In order to characterize the influence of the caldera structure on the regional tectonics, we analysed the structural framework of the caldera and direct surroundings using remote sensing (optical imagery and high resolution DEM from TanDEM-X data). Then we made detailed field measurements (500 data) by analysing azimuth, dip, and opening of eruptive fissures, dikes, faults and extension fractures. Both remote sensing and field measurements have been then integrated producing a detailed structural map of Askja. Our results show

  1. 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. PMID:17385047

  2. Delayed Superior Orbital Fissure Syndrome After Reconstruction of Blowout Fracture.

    PubMed

    Kim, Young Joon; Choi, Woong Kyu

    2016-01-01

    The superior orbital fissure syndrome (SOFS) has been known to be a condition caused by impairment of the nerves that cross the superior orbital fissure. Traumatic SOFS is an uncommon complication which occurs usually within 48 hours after a facial injury. A 25-year-old male sustained facial trauma following an altercation. Clinical findings on presentation included swelling, ecchymosis, hyphema, subretinal hemorrhage, and mild extraocular movement limitation upon lateral gaze on his right eyelids. Facial computed tomography scan confirmed fractures of the medial walls of the right orbit and herniation of orbital soft tissue without the incarceration of medial rectus muscle. Ten days after the trauma, the operation was performed. On postoperative day 16, the patient showed ptosis of the right upper eyelid with a fixed pupil, and there was a hypoesthesia over the distribution of the right supraorbital and supratrochlear nerves. The authors diagnosed as a delayed SOFS and prescribed 4 mg of methylprednisolone q.i.d. for 30 days. After steroid therapy, extraocular movement limitations improved progressively. After 8 months, movement was completely restored. The authors experienced delayed SOFS on posttrauma day 27, and it was treated by steroid therapy. Surgical intervention is required when there is an evident etiology such as underlying hematoma or plate migration. If the reason is not clear like our case, steroid therapy can be considered as one of the options. Particularly, the authors should give special attention to the patient who has congenitally narrow superior orbital fissure, like Fujiwara et al suggested. PMID:26674904

  3. 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.

  4. 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

  5. A Review of Cyanoacrylate Liquid Skin Protectant and Its Efficacy on Pedal Fissures

    PubMed Central

    Vlahovic, Tracey C.; Hinton, Elizabeth A.; Chakravarthy, Debashish; Fleck, Cynthia Ann

    2011-01-01

    Introduction Skin fissures are a common dermatologic condition caused by excessive dry skin, numerous systemic diseases, and backless shoe gear. They are defects in skin that fall into the category of damaged, partial-thickness skin wounds, as opposed to full-thickness wounds. Patients with heel fissures are at an increased risk for developing infection, which could cause more severe issues, especially in patients with diabetes and peripheral vascular disease. Methods Five patients from Temple Foot and Ankle Institute, Philadelphia, PA, with a total of 8 heel fissures and 2 hallux fissures, were studied. Patients were dispensed 9 vials of a cyanoacrylate liquid skin protectant (Marathon™, Medline Industries, Inc, Mundelein, IL) to be applied to the fissure every 3 days. Patients returned every 2 weeks for follow-up in clinic. Results The hallux fissures and 4 of the heel fissures went to complete closure after 2 weeks. There was an average decrease of 1.16 cm in length of the heel fissure dimensions after 2 weeks and an average decrease of 1.1 cm in length of the hallux fissures. Conclusion This novel skin protectant proved to be a comfortable, easy, and effective tool in aiding the resolution of pedal skin fissures. PMID:24527155

  6. 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. PMID:26349852

  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. 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.

  9. Caries-preventive effect of fissure sealants: a systematic review.

    PubMed

    Mejàre, Ingegerd; Lingström, Peter; Petersson, Lars G; Holm, Anna-Karin; Twetman, Svante; Källestål, Carina; Nordenram, Gunilla; Lagerlöf, Folke; Söder, Birgitta; Norlund, Anders; Axelsson, Susanna; Dahlgren, Helena

    2003-12-01

    The objectives of this study were to evaluate systematically the evidence of the caries-preventive effect of fissure sealing of occlusal tooth surfaces and to examine factors potentially modifying the effect. The search strategies included electronic databases, reference lists of articles, and selected textbooks. Inclusion criteria were randomized or quasi-randomized clinical trials or controlled clinical trials comparing fissure sealing with no treatment or another preventive treatment in children up to 14 years of age at the start; the outcome measure was caries increment; the diagnostic criteria had been described; and the follow-up time was at least 2 years. Inclusion decisions were taken and grading of the studies was done independently by two of the authors. The main measure of effect was relative risk reduction. Thirteen studies using resin-based or glass ionomer sealant materials were included in the final analysis. The results showed that most studies were performed during the 1970s and a single application had been utilized. The relative caries risk reduction pooled estimate of resin-based sealants on permanent 1st molars was 33% (relative risk = 0.67; CI = 0.55-0.83). The effect depended on retention of the sealant. In conclusion, the review suggests limited evidence that fissure sealing of 1st permanent molars with resin-based materials has a caries-preventive effect. The evidence is incomplete for permanent 2nd molars, premolars and primary molars and for glass ionomer cements. Overall, there remains a need for further trials of high quality, particularly in child populations with a low and a high caries risk, respectively. PMID:14960003

  10. 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

  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. 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

  13. 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.

  14. 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

  15. Fracture mechanical behavior of red sandstone containing a single fissure and two parallel fissures after exposure to different high temperature treatments

    NASA Astrophysics Data System (ADS)

    Yang, Sheng-Qi; Jing, Hong-Wen; Huang, Yan-Hua; Ranjith, P. G.; Jiao, Yu-Yong

    2014-12-01

    A detailed understanding of the brittle deformation behavior of sandstone containing pre-existing flaws at elevated temperatures is a key concern in underground engineering. In this research, uniaxial compression tests were performed to evaluate the effect of high temperature treatments (300, 600 or 900 °C) on the strength, deformability and fracture coalescence behavior of a sandstone containing either a single fissure or two parallel fissures. All experiments focused on rectangular prismatic (80 × 160 × 30 mm) specimens of red sandstone. Constant strain rate experiments were performed on either: (1) specimens that contained a single 2 mm-wide fissure or (2) specimens that contained two 2 mm-wide parallel fissures. The specimens containing either one or two fissures were either left at room temperature (i.e., no heat treatment), or heat treated to 300, 600 or 900 °C prior to experimentation. The results demonstrated that, in all cases, the strength and stiffness of red sandstone was increased at 300 °C, before decreasing up to our maximum temperature of 900 °C. However, the peak strain at failure always showed an increase when the temperature was increased. The crack initiation, propagation and coalescence process were monitored during the deformation using both photographic monitoring and acoustic emission (AE) monitoring techniques. The monitoring results showed that the cracking process depended on both the fissure geometry and the heat treatment temperature. The potential mechanisms causing the differences in the mechanical behavior observed with increasing temperature are discussed, as is the influence of the single fissure and the two parallel fissures on the crack evolution process. These results are important and valuable to understand the fracture mechanism of rock engineering in deep underground mining excavations and nuclear waste depositories.

  16. 21 CFR 872.3765 - Pit and fissure sealant and conditioner.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Pit and fissure sealant and conditioner. 872.3765 Section 872.3765 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3765 Pit and fissure sealant...

  17. 21 CFR 872.3765 - Pit and fissure sealant and conditioner.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Pit and fissure sealant and conditioner. 872.3765 Section 872.3765 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3765 Pit and fissure sealant...

  18. 21 CFR 872.3765 - Pit and fissure sealant and conditioner.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Pit and fissure sealant and conditioner. 872.3765 Section 872.3765 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3765 Pit and fissure sealant...

  19. 21 CFR 872.3765 - Pit and fissure sealant and conditioner.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Pit and fissure sealant and conditioner. 872.3765 Section 872.3765 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3765 Pit and fissure sealant...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 ...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 ...

  2. Holocene intracontinental deformation of the northern North China Plain: Evidence of tectonic ground fissures

    NASA Astrophysics Data System (ADS)

    Xu, Liqing; Li, Sanzhong; Cao, Xianzhi; Somerville, I. D.; Suo, Yanhui; Liu, Xin; Dai, Liming; Zhao, Shujuan; Guo, Lingli; Wang, Pengcheng; Cao, Huahua

    2016-04-01

    Following the collecting and analyzing of field data on the geometry and kinematics characteristics of ground fissures in the northern North China Plain (NNCP), this paper shows that en échelon ground fissures or tectonic ground fissures with a length of several meters to tens of kilometers extending along active faults are possibly controlled by underlying active faults. There are two groups of tectonic ground fissures developed in the NNCP. One group consists of ENE-trending "right-stepping" ground fissures, some of which have a component of sinistral motion. The other group is NNE-trending "left-stepping" ground fissures with dextral motion. A large amount of data from trenches, boreholes and seismic exploration reflect that they are active-faulting-related. The NNW-trending regional extensional stress field and the reactivation of pre-existing faults are the major factors controlling ground fissures. Data from the Quaternary sedimentary records, deep incised valleys, the distribution of earthquakes and ground fissures, and our field work show that the Holocene intracontinental deformation of the NNCP is characterized by intense faulting and northwestward tilting, which may be related to a NNW-SSE-oriented tensional stress field in the shallow crust and asthenospheric upwelling in the mantle.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  4. 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

  5. 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.

  6. 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. PMID:24722094

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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. PMID:26298801

  12. 21 CFR 872.3765 - Pit and fissure sealant and conditioner.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3765 Pit and fissure sealant and... depressions (faults in the enamel) in the biting surfaces of teeth to prevent cavities. (b)...

  13. Use of CO2 laser in pit and fissure caries prevention: clinical evaluation

    NASA Astrophysics Data System (ADS)

    Brugnera, Aldo, Jr.; Rosso, Naomi; Duarte, Danilo; Guedes Pinto, Antonio C.; Genovese, Walter J.

    1997-05-01

    In this four-year follow up in vivo controlled study, 112 human permanent first molars, from children between the ages of 6 and 11 years old were used to investigate the viability of the CO2 laser in promoting carie-free occlusal surfaces in permanent molars, as an isolated form of treatment or associated with conventional fissure sealants. The findings suggest that occlusal caries prevention only by means of CO2 laser irradiation is not effective; that the utilization of photo-activated sealants, as well as its association with CO2 laser, applied over the occlusal fissures, are effective means of preventing occlusal caries and that the application of CO2 laser over occlusal fissures, prior to the application of a photo-activated fissure sealant, improves the retention of the sealant.

  14. 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

  15. Land subsidence and earth fissures due to groundwater withdrawal in the Southern Yangtse Delta, China

    NASA Astrophysics Data System (ADS)

    Zhang, Yun; Xue, Yu-Qun; Wu, Ji-Chun; Yu, Jun; Wei, Zi-Xin; Li, Qin-Fen

    2008-08-01

    Excessive extraction of groundwater has caused severe land subsidence and earth fissures in the Southern Yangtse Delta, China. Based on field data, the temporal and spatial distribution of land subsidence is investigated and the causes for earth fissures are analyzed. The areal distribution of the land subsidence is closely related to the cones of depression in the main exploited aquifers. The compaction of a hydrostratigraphic unit depends on its mechanical behavior, thickness, compressibility, and the piezometric level changing. The primary subsidence layers in Shanghai have been the first aquitard before 1990 and the third confined aquifer since then. But the second aquitard unit was the primary subsidence layer in Changzhou. Earth fissures, trending in several directions, occurred in the Husu tectonic zone. They were mainly caused by differential subsidence and horizontal displacement that resulted from tensile stress and shear stress in units. The majority of fissures in the study area are tensile.

  16. 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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  17. 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.

  18. Adaptive Management of Land Subsidence and Ground Fissuring in the Chino Groundwater Basin, California

    NASA Astrophysics Data System (ADS)

    Malone, A.; Rolfe, T.; Wildermuth, M.; Kavounas, P.

    2014-12-01

    The Chino Basin, located in southern California, is a large alluvial groundwater basin with storage in excess of five million acre-feet. The basin has a long history of groundwater development for various uses dating back to the early 1900s. As a result, piezometric heads declined basin-wide during the past century - in some areas by more than 200 feet. Declines of this magnitude typically cause irreversible aquifer-system compaction, which in turn results in subsidence at the ground surface. In portions of Chino Basin, land subsidence has been differential and accompanied by ground fissuring, which damaged existing infrastructure and poses concerns for new and existing development.Chino Basin Watermaster, the agency responsible for groundwater basin management, has recognized that land subsidence and ground fissuring should be minimized to the extent possible. At the same time, Watermaster is implementing aggressive groundwater-supply programs that include controlled overdraft and the possibility of causing head declines in areas prone to subsidence and fissuring. The groundwater-supply programs must also address the subsidence and fissuring phenomena.From 2001 to 2005, Watermaster conducted a technical investigation to characterize the extent, rate, and mechanisms of subsidence and fissuring. The investigation employed InSAR and ground-level surveying of benchmarks to monitor ground-surface deformation, and borehole extensometers and piezometric monitoring to establish the relationships between groundwater production, piezometric levels, and aquifer-system deformation. Based on the results of the investigation, Watermaster developed: (i) subsidence-management criteria for the areas experiencing acute subsidence and fissuring, and (ii) an adaptive management program to minimize the potential for future subsidence and fissuring across the entire Chino Basin. The science-based program includes ongoing monitoring, which now includes sophisticated fissure

  19. Radar Observations of Fissure-fed Basaltic Lava Flows, Craters of the Moon, Idaho

    NASA Technical Reports Server (NTRS)

    Martel, L.; Greeley, R.

    1985-01-01

    Changes in surface roughness of lava flows, estimated from dual polarization, synthetic aperture, X and L band side-looking airborne radar images, were tested as a means of locating fissure vent areas. If lava textures proess from smooth, near-vent shelly pahoehoe to hummocky pahoehoe to aa with distance from fissure vents, then radr images of the lava flows would show a progression from dark to brighter tones due to the flows' increasing radar back-scatter.

  20. Radar observations of fissure-fed basaltic lava flows, Craters of the Moon, Idaho

    NASA Astrophysics Data System (ADS)

    Martel, L.; Greeley, R.

    1985-04-01

    Changes in surface roughness of lava flows, estimated from dual polarization, synthetic aperture, X and L band side-looking airborne radar images, were tested as a means of locating fissure vent areas. If lava textures proess from smooth, near-vent shelly pahoehoe to hummocky pahoehoe to aa with distance from fissure vents, then radr images of the lava flows would show a progression from dark to brighter tones due to the flows' increasing radar back-scatter.

  1. 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.

  2. Fracturing and earthquake activity within the Prestahnúkur fissure swarm in the Western Volcanic Rift Zone of Iceland

    NASA Astrophysics Data System (ADS)

    Hjartardóttir, Ásta Rut; Hjaltadóttir, Sigurlaug; Einarsson, Páll; Vogfjörd, Kristín.; Muñoz-Cobo Belart, Joaquín.

    2015-12-01

    The Prestahnúkur fissure swarm is located within the ultraslowly spreading Western Volcanic Zone in Iceland. The fissure swarm is characterized by normal faults, open fractures, and evidence of subglacial fissure eruptions (tindars). In this study, fractures and faults within the Prestahnúkur fissure swarm were mapped in detail from aerial photographs to determine the extent and activity of the fissure swarm. Earthquakes during the last ~23 years were relocated to map the subsurface fault planes that they delineate. The Prestahnúkur fissure swarm is 40-80 km long and up to ~20 km wide. Most of the areas of the fissure swarm have been glacially eroded, although a part of it is covered by postglacial lava flows. The fissure swarm includes numerous faults with tens of meters vertical offset within the older glacially eroded part, whereas open fractures are found within postglacial lava flows. Comparison of relocated earthquakes and surface fractures indicates that some of the surface fractures have been activated at depth during the last ~23 years, although no dike intrusions have been ongoing. The existence of tindars nevertheless indicates that dike intrusions and rifting events do occur within the Prestahnúkur fissure swarm. The low-fracture density within postglacial lava flows and low density of postglacial eruptive fissures indicate that rifting episodes occur less often than in the faster spreading Northern Volcanic Zone.

  3. 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

  4. 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

  5. Automatic recognition of lung lobes and fissures from multislice CT images

    NASA Astrophysics Data System (ADS)

    Zhou, Xiangrong; Hayashi, Tatsuro; Hara, Takeshi; Fujita, Hiroshi; Yokoyama, Ryujiro; Kiryu, Takuji; Hoshi, Hiroaki

    2004-05-01

    Computer-aided diagnosis (CAD) has been expected to help radiologists to improve the accuracy of abnormality detection and reduce the burden during CT image interpretations. In order to realize such functions, automated segmentations of the target organ regions are always required by CAD systems. This paper describes a fully automatic processing procedure, which is designed to identify inter-lobe fissures and divide lung into five lobe regions. The lung fissures are disappeared very fuzzy and indefinite in CT images, so that it is very difficult to extract fissures directly based on its CT values. We propose a method to solve this problem using the anatomy knowledge of human lung. We extract lung region firstly and then recognize the structures of lung vessels and bronchus. Based on anatomy knowledge, we classify the vessels and bronchus on a lobe-by-lobe basis and estimate the boundary of each lobe region as the initial fissure locations. Within those locations, we extract lung fissures precisely based on an edge detection method and divide lung regions into five lung lobes lastly. The performance of the proposed method was evaluated using 9 patient cases of high-resolution multi-slice chest CT images; the improvement has been confirmed with the reliable recognition results.

  6. In Vitro Comparison of Microleakage of Two Materials Used as Pit and Fissure Sealants

    PubMed Central

    Bahrololoomi, Zahra; Soleymani, Aliasghar; Heydari, Zahra

    2011-01-01

    Background and aims Marginal seal of the material is extremely important in fissure sealant therapy. The aim of this study was to investigate microleakage of flowable composite resins and conventional fissure sealants with or without dentin bonding agent. Materials and methods The occlusal surface of 60 intact extracted human premolars, divided into four groups, were cleaned with pumice/slurry, etched with 37% phosphoric acid for 15 seconds, rinsed and dried. Groups were treated differ-ently: Excite bonding agent followed by Helioseal F fissure sealant in group1; Helioseal F alone in group 2; Excite bonding agent followed by Tetric Flow in group 3; and Tetric Flow alone in group 4. Light-curing was done after each application. After thermocycling, the whole surface of each specimen was coated with nail varnish except for one millimeter around the fissure sealant. The teeth were immersed in 2% basic fuchsin for 24 hours and then sectioned buccolingually. The sections were analyzed for leakage under a stereomicroscope. Data was analyzed by Kruskal-Wallis and Mann-Whitney tests at asignificance level of P < 0.05. Results There were no statistically significant differencesbetween the study groups in terms of the mean microleakage scores (P > 0.05), except for groups 2 and 4 (P = 0.002) and groups 3 and 4 (P = 0.033). Conclusion Use of a flowable composite with bonding agent is a good alternative for sealing pits and fissures; however, further in vitro and in vivo studies are necessary. PMID:22991611

  7. 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.

  8. 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.

  9. Pulmonary Fissure Detection in CT Images Using a Derivative of Stick Filter.

    PubMed

    Xiao, Changyan; Stoel, Berend C; Bakker, M Els; Peng, Yuanyuan; Stolk, Jan; Staring, Marius

    2016-06-01

    Pulmonary fissures are important landmarks for recognition of lung anatomy. In CT images, automatic detection of fissures is complicated by factors like intensity variability, pathological deformation and imaging noise. To circumvent this problem, we propose a derivative of stick (DoS) filter for fissure enhancement and a post-processing pipeline for subsequent segmentation. Considering a typical thin curvilinear shape of fissure profiles inside 2D cross-sections, the DoS filter is presented by first defining nonlinear derivatives along a triple stick kernel in varying directions. Then, to accommodate pathological abnormality and orientational deviation, a [Formula: see text] cascading and multiple plane integration scheme is adopted to form a shape-tuned likelihood for 3D surface patches discrimination. During the post-processing stage, our main contribution is to isolate the fissure patches from adhering clutters by introducing a branch-point removal algorithm, and a multi-threshold merging framework is employed to compensate for local intensity inhomogeneity. The performance of our method was validated in experiments with two clinical CT data sets including 55 publicly available LOLA11 scans as well as separate left and right lung images from 23 GLUCOLD scans of COPD patients. Compared with manually delineating interlobar boundary references, our method obtained a high segmentation accuracy with median F1-scores of 0.833, 0.885, and 0.856 for the LOLA11, left and right lung images respectively, whereas the corresponding indices for a conventional Wiemker filtering method were 0.687, 0.853, and 0.841. The good performance of our proposed method was also verified by visual inspection and demonstration on abnormal and pathological cases, where typical deformations were robustly detected together with normal fissures. PMID:26766371

  10. 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.

  11. A novel method of anal fissure laser surgery: a pilot study.

    PubMed

    Esfahani, Mehran Nasr; Madani, Golnoush; Madhkhan, Sepideh

    2015-08-01

    Anal fissure is a common painful problem, affecting all age groups. Its pathophysiology is based on high sphincter pressures and reduced blood supplying and treatments which means that it generally reduces anal pressures and increases anodermal blood flow. Since each of the anal fissure's routine therapies has some limitations such as definite risk of permanent fecal incontinence and high recurrence rate, we tried to find a more effective and less invasive procedure. In this pilot study which was implemented on 25 male and female patients aged 20-75 years, diagnosed clinically with chronic anal fissure, the Carbon Dioxide Laser Fractional was used to treat patients. In order to first remove fibrotic and granulation tissues, the base and the edges of the fissure were laser beamed. Eight spots were made on the sphincter by the laser on its continuous mode; somehow, they were passed through the full thickness of sphincter without interrupting its continuance. Afterwards, the area around the fissure ulcer was irradiated by deep fractional mode of the laser to stimulate the submucosa to regenerate and rejuvenate. After going through this procedure, patients were followed up within 6 months to 1 year. Pain, bleeding, and constipation were significantly improved. None of the patients had recurrence after a 1-year follow-up, and none of them had fecal incontinence and/or inability to control the passage of gas too. This study revealed that this new laser-based surgery is a simple, safe, and effective procedure to treat the anal fissure that can be performed with local anesthesia in an outpatient clinic with minimal postoperative morbidity. PMID:26067925

  12. Ice-Confined Basaltic Eruptive Fissure Complexes in Iceland: Accessible Analogs for Understanding Shallow Submarine Ridge Construction

    NASA Astrophysics Data System (ADS)

    Skilling, I. P.; Mercurio, E.; Cameron, B. I.

    2009-12-01

    In southwest Iceland, the onshore Mid-Atlantic Ridge (Reykjanes Ridge) forms a series of fissure and central vent (“shield”) volcanic complexes, known as the Western Volcanic Zone (WVZ). Sveifluháls is one of the longest fissure-fed complexes in the WVZ, and was erupted in an ice-confined environment during the Last Glacial Maximum. There are more than 1000 similar such glaciovolcanic ridges in Iceland, but there are few detailed studies of their construction. The complexes are both an important record of North Atlantic terrestrial ice presence and thicknesses in the Pleistocene, and are accessible analogs for submarine basaltic ridge volcanism in water less than a few hundred metres deep. This study focuses on the volcanic and sedimentary processes, products and depositional environments at Sveifluháls. Sveifluháls is a complex of closely spaced, sub-parallel, and multiple vent ridges. Ridges are constructed of numerous, regularly-spaced to overlapping and steep-sided topographic highs (point-source vents or tuff cones) and short, lower, intervening ridge segments (fissure vents or “tuff ridges”). Both tuff cones and tuff ridges consist dominantly of basal subaqueous lavas draped by phreatomagmatic tephra. Point-source vents have an average spacing of 0.7 km. Up to nine sub-parallel fissures/ridges occur, spaced 0.03-0.5 km apart. Ridges range from a few hundred metres to 21.5km in length. The majority of the phreatomagmatic has been rotated, slumped or slid. An upper sequence of inward and outward-dipping, over-steepened (rotated) “soft-margined” domains and angular blocks of bedded, subaqueously-deposited “Surtseyan” lapilli tuff, overlies more widespread aprons of very similar, but mostly slumped massive tephra. Important results to date include the observation that 1-2m wide dikes, emplaced into formerly wet unconsolidated tephra, form a volumetrically important part of the complex. The host tephra commonly shows evidence of deformation and

  13. Radiating graben-fissure systems in the Ulfrun Regio area, Venus

    NASA Astrophysics Data System (ADS)

    Studd, D.; Ernst, R. E.; Samson, C.

    2011-09-01

    Radiating graben-fissure systems are common on Venus. Most are thought to be underlain by mafic dykes, fed by centrally-located magmatic centres. From previous work it has been shown that these magmatic plumbing systems can extend out up to 2000 km or more and that interaction between neighbouring systems can provide insight into the relative chronology of their magmatic centres. Systematic mapping of graben-fissure systems has potential as a tool for regional magmatic chronology and correlation on Venus. This methodology is applied to the Ulfrun Regio area (200-240°E, 0-25°N) where we mapped 47,000 graben and fissures. From these, 66 radiating systems comprised of 13,000 individual graben and fissures, and having radii of up to 2000 km have been identified, and are interpreted to be underlain by dyke swarms focussed on magmatic centres. Cross-cutting relationships among these systems and with the Hecate Chasma rift zone have been examined to provide a relative chronology for the magmatic centres. Two trends emerged: (a) an apparent younging from the southwest to northeast of the study area and (b) a cluster of older ages in the southwest, linked to the Atla Regio mantle plume.

  14. Study of Operated Patients of Lateral Internal Anal Sphincterotomy for Chronic Anal Fissure

    PubMed Central

    Patel, Harshad Shankarlal; Chavda, Jagdish; Parikh, Jayesh; Naik, Nehal

    2013-01-01

    Introduction: Anal fissure causes significant morbidity in the population. It is proposed that elevated sphincter pressures may cause ischaemia of the anal lining and this may be responsible for the pain of anal fissures and their failure to heal. When pharmacologic therapy fails or fissures recur frequently, lateral internal sphincterotomy is the surgical treatment of choice. Material and Methods: Retrospective analysis was done of admitted and operated patients of anal fissure by lateral anal internal sphincterotomy either by open or closed technique between April 2010 and November 2011 in Gujarat Medical Education & Research Society Medical College, Sola, Ahmedabad, India. The follow-up data of all patients was evaluated for pain relief, recurrence, wound infection, incontinence to flatus or stool or both for a period of up to 6 months. Results: Wound infection rate was 10.3% in open method and 4.2% in closed method. Incontinence to flatus was 8.3% in closed method and 3.4% in open method. This was temporary and controlled within a 1 week. Incontinence to stool was 3.4% in open method which was temporary and controlled within 2 weeks while none in closed method. None of the patients in either group had come with recurrence within 6 months follow-up. Conclusion: Lateral anal internal sphincterotomy is safe regarding long term incontinence and effective regarding recurrence. PMID:24551659

  15. Effects of anterior cingulate fissurization on cognitive control during stroop interference.

    PubMed

    Huster, Rene J; Wolters, Carsten; Wollbrink, Andreas; Schweiger, Elisabeth; Wittling, Werner; Pantev, Christo; Junghofer, Markus

    2009-04-01

    The midcingulate cortex, as part of the more anteriorly located cingulate regions, is thought to play a major role in cognitive processes like conflict monitoring or response selection. Regarding midcingulate fissurization, the occurrence of a second or paracingulate sulcus is more common in the left than in the right hemisphere and has been shown to be associated with an advantageous performance on tests of executive functions. However, the cognitive mechanisms underlying such behavioral differences are completely unknown. The current study addressed this issue by comparing subjects with a low and a high degree of left hemispheric midcingulate fissurization while collecting behavioral as well as electrophysiological correlates of Stroop interference. A high degree of fissurization was associated with decreased behavioral Stroop interference accompanied by a stronger and prolonged frontal negative potential to incongruent trials starting around 320 ms. This increased frontal negativity is assumed to reflect an enhanced activity of a conflict monitoring system located in the midcingulate cortex. In contrast and starting around 400 ms, subjects with low fissurization revealed an increased positivity over parieto-occipital regions suggesting a compensatory need for enhanced effortful cognitive control in this group. These results contribute to the understanding of the neuronal implementation of individual differences regarding attentional mechanisms. PMID:18570202

  16. Giant desiccation fissures on the Black Rock and Smoke Creek Deserts, Nevada

    USGS Publications Warehouse

    Willden, R.; Mabey, D.R.

    1961-01-01

    Open fissures, from 100 to several hundred feet apart, that have produced polygonal patterns on the Black Rock Desert, Nevada, are believed to be giant desiccation cracks resulting from a secular trend toward aridity in the last few decades. Similar features on the Smoke Creek Desert probably have the same origin.

  17. Mapping the fissure potential zones based on microtremor measurement in Denpasar City, Bali

    NASA Astrophysics Data System (ADS)

    Prabowo, U. N.; Marjiyono; Sismanto

    2016-01-01

    Denpasar City and its vicinity considered as the areas with excessive ground water exploitation and high earthquake intensity. These conditions will cause these area potential with land subsidence which is triggering ground fissures. This research aims are to mapping the fissures potential areas based on microtremor measurement in Denpasar City and its vicinity. Ground fissures will happen if the land subsidence occurs in the areas which have different bedrock height beneath its sedimentary layer. The height of bedrock is determined by reducing surface elevation with the sedimentary layer thickness. This sedimentary layer thickness obtained from microtremor measurement using HVSR method, and Shear wave velocity (VS) obtained from microtremor array measurement which is analyzed by Spatial Auto Correlation (SPAC) method. The result from HVSR method as well as Peak Ground Acceleration (PGA) value are then analyzed to get ground shear strain value, which is the soil surface strain and its effect when earthquake occurs. Based on the bedrock map, it can be estimated that the bedrock layer forms structure in the southern part of the research areas and the potential fissuring area due to the massive ground water exploitation is in the west Denpasar Subdistrict. In addition, based on the bedrock map and ground shear strain value which combined with Simple Additive Weight (SAW) method, there are two areas having Assuring potential, i.e west and south Denpasar Subdistricts.

  18. Identification of genetic loci underlying the kernel fissure-resistance exhibited by 'cypress' and 'saber'

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The economic value of broken rice is about half that of whole milled rice, so one goal of producers, millers, and rice breeders is to reduce broken grains that result from the dehusking and milling processes One of the primary causes of rice breakage is fissuring, or cracking, of the rice before it ...

  19. 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

  20. Effects of menthol essence and breast milk on the improvement of nipple fissures in breastfeeding women

    PubMed Central

    Akbari, Sedigheh Amir Ali; Alamolhoda, Seideh Hanieh; Baghban, Alireza Akbarzadeh; Mirabi, Parvaneh

    2014-01-01

    Background: Nipple fissure is a common disorder during breastfeeding. With high prevalence of nipple fissures and its impacts on breastfeeding, as well as the existence of evidence in favor of the application of peppermint as an antiinflammatory and antiinfection herb, the purpose of this study is to determine the effect of Menthol essence on improving nipple fissures in the primiparous breastfeeding women. Materials and Methods: This study was conducted using a clinical trial method. Samples were divided randomly into two groups of 55 women. The women in the peppermint group applied four drops of Menthol essence on their nipple and areola after each feeding. The control group applied four drops of their own milk on the nipple and areola after each feeding. Then, the two groups were studied on days 10 and 14 postpartum. For intensity of pain, the visual analog scale (0-10 cm) and to measure the severity of damage, Amir scale (1-10 cm) were applied and the existence or lack of nipple discharge was also recorded. The data were analyzed using SPSS 17 software. Results: The mean intensity of pain and nipple fissure before treatment (8.55 ± 1.74) and day 10 after delivery (4.26 ± 1.57) and before treatment and day 14 after delivery in the case group (1.32 ± 1.02) had a significant difference (P < 0.001). Nipple discharge between the two groups, before treatment (%75.2) and day 10 after delivery (%31.6) and before treatment and day 14 after delivery (%15.7), the case group had a significant difference (P < 0.001). Conclusion: Menthol essence can improve nipple fissures in the primiparous breastfeeding women. PMID:25364362

  1. Soil gas composition from the 2001-2002 fissure in the Lakki Plain (Nisyros Island, Greece): evidences for shallow hydrothermal fluid circulation

    NASA Astrophysics Data System (ADS)

    Venturi, Stefania; Tassi, Franco; Kanellopoulos, Christos; Vaselli, Orlando; Caponi, Chiara; Ricci, Andrea; Raspanti, Alessio; Gallorini, Andrea; Cabassi, Jacopo; Vougioukalakis, Georges

    2016-04-01

    Nisyros volcano (Aegean Sea, Greece) is currently classified in the "Very High Threat" category (Kinvig et al., 2010). Although the last volcanic activity, consisting of phreatic eruptions, occurred in the 19th century, Nisyros experienced an intense seismic activity during 1996-1998 accompanied by ground deformation and changes in the chemistry of fumarolic gases (Chiodini et al., 2002), pointing to a renewed unrest. Between November 2001 and December 2002, a NNE-oriented 600 m long fissure opened in the vegetated central part of the Lakki Plain. The fissure, 1-5 m wide and up to 15-20 m deep, showed neither vertical displacements nor gas release. No changes in the seismic and volcanic activity were observed during or after this event, which was interpreted as related to collapse of the upper caldera floor fine sediment cover (<50 m thick) induced by hydrothermal fluid circulation (Vougioukalakis and Fytikas, 2005). In June 2015, diffuse CO2 flux measurements, in combination with sampling and chemical analysis of the interstitial soil gases, were performed in (i) the fissure bottom, (ii) the adjacent vegetated areas in the Lakki Plain, (iii) the near hydrothermal craters (Stefanos, Kaminakia, Lofos domes), and (iv) sites located outside the caldera (blank values). The fissure showed neither temperature (<30 °C) nor CO2 fluxes (<10 gm-2d-1) anomalies with respect to the blank sites and the Lakki Plain, with values strikingly lower than those measured in the hydrothermal craters (up to 98 °C and 208 gm-2d-1, respectively). Contrarily, the CO2 concentrations in the interstitial soil gases from the fissure (up to 513 mmol/mol) were markedly higher than the background values and comparable with those measured in the craters (up to 841 mmol/mol). Relatively high H2S, H2 and CH4 contents in soil gases from the fissure confirm the hydrothermal origin of these soil gases. However, their CH4/CO2 ratio were lower than those measured in the soil gases from the craters

  2. Enamel Surface with Pit and Fissure Sealant Containing 45S5 Bioactive Glass.

    PubMed

    Yang, S-Y; Kwon, J-S; Kim, K-N; Kim, K-M

    2016-05-01

    Enamel demineralization adjacent to pit and fissure sealants leads to the formation of marginal caries, which can necessitate the replacement of existing sealants. Dental materials with bioactive glass, which releases ions that inhibit dental caries, have been studied. The purpose of this study was to evaluate the enamel surface adjacent to sealants containing 45S5 bioactive glass (BAG) under simulated microleakage between the material and the tooth in a cariogenic environment. Sealants containing 45S5BAG filler were prepared as follows: 0% 45S5BAG + 50.0% glass (BAG0 group), 12.5% 45S5BAG + 37.5% glass (BAG12.5 group), 25.0% 45S5BAG + 25.0% glass (BAG25.0 group), 37.5% 45S5BAG + 12.5% glass (BAG37.5 group), and 50.0% 45S5BAG + 0% glass (BAG50.0 group). A cured sealant disk was placed over a flat bovine enamel disk, separated by a 60-µm gap, and immersed in lactic acid solution (pH 4.0) at 37 °C for 15, 30, and 45 d. After the storage period, each enamel disk was separated from the cured sealant disk, and the enamel surface was examined with optical 3-dimensional surface profilometer, microhardness tester, and scanning electron microscopy. The results showed a significant increase in roughness and a decrease in microhardness of the enamel surface as the proportion of 45S5BAG decreased (P< 0.05). In the scanning electron microscopy images, enamel surfaces with BAG50.0 showed a smooth surface, similar to those in the control group with distilled water, even after prolonged acid storage. Additionally, an etched pattern was observed on the surface of the demineralized enamel with a decreasing proportion of 45S5BAG. Increasing the 45S5BAG filler contents of the sealants had a significant impact in preventing the demineralization of the enamel surface within microgaps between the material and the tooth when exposed to a cariogenic environment. Therefore, despite some marginal leakage, these novel sealants may be effective preventive dental materials for inhibiting

  3. Construction and Evolution of an Ice-Confined Basaltic Eruptive Fissure Complex: Sveifluhals, SW Iceland

    NASA Astrophysics Data System (ADS)

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

    2009-05-01

    Ice-confined fissure-fed basaltic eruptions were common in Iceland during the Pleistocene. Most of these generated complexes consisting of closely spaced, sub-parallel, multi-vent ridges. Individual ridges are constructed mostly of numerous linked steep-sided mounds (point-source vents) and short ridges (fissure vents) of subaqueous lavas, most of which are draped by phreatomagmatic tephra. There are more than 1000 such ridges in Iceland and they represent an important, largely untapped, database on North Atlantic terrestrial ice conditions. Some of these complexes were of comparable length to the famous Laki fissure eruptions of 1783-1785. Sveifluhals is a 21.5-km long formerly ice-confined fissure complex of unknown age, but similar nearby centers have been dated at about 47ka. Ice-thickness estimates, based on volatile analysis of pillow rind glass vary from 70-400m. This is the first detailed study of such a complex, which focuses on how it was constructed in space and time, how it differs from published studies of simple single short fissure ice-confined centers, and how it interacted with the overlying ice. Initial results have identified vents with an average spacing of 0.7km on at least nine sub-parallel fissures, which are spaced about 0.1-0.5km apart. The vents are dominated by inward and outward-dipping rotated (oversteepened) blocks of bedded tephra, which overlies mostly slumped massive tephra. The tephra drapes subaqueous lava mounds that display marginal steep- ridges of subaqueous lavas, that may have been emplaced in short sub-ice tunnels. We have also identified several now dry lakes that formed in some inter-ridge areas, but whose age relationship to ridge construction is as yet uncertain. We present here our preliminary data on vent locations and estimates of product volumes, volumes of ice melted, and location of possible meltwater pathways. We discuss the most important differences of the processes and products of such ridge complexes compared

  4. Prevalence of Dental Caries and Fissure Sealants in a Portuguese Sample of Adolescents

    PubMed Central

    Veiga, Nélio J.; Pereira, Carlos M.; Ferreira, Paula C.; Correia, Ilidio J.

    2015-01-01

    Introduction The aims of this study were to assess the prevalence of dental caries and the DMFT index, as well as the distribution pattern of pit and fissure sealants on permanent teeth in a Portuguese sample of adolescents, and to assess whether the existing usage of sealants and socio-demographic factors are correlated to caries prevalence on the examined sample. Materials and Methods A cross-sectional study was designed with a sample of 447 adolescents aged 12 to 18 years old, attending a public school in Sátão, Portugal. A self-administered questionnaire with questions about oral health behaviours and socio-economic status was answered by adolescents in the classroom. Clinical examination of oral health status and assessment of fissure sealants were accomplished by only one trained member of the research team. Results We obtained a DMFT index of 3.32 (2.92), which indicates a moderate level of prevalence of dental caries. When considering a DMFT = 0, we found significant statistical differences between the parents´ level of education (≤ 4th grade = 26.3 vs 5th–12th grade = 18.8 vs <12th grade = 43.3, p = 0.001), gender (male = 27.3 vs female = 19.6, p = 0.04), age (≤15 years = 27.1 vs <15 years = 18.5, p = 0.02), presence of fissure sealants (yes = 30.6 vs no = 13.5, p = 0.001) and experience of dental pain (no = 25.4 vs yes = 16.8, p = 0.02). When analyzing the prevalence of fissure sealants, we verified that 58.8% of adolescents had at least one fissure sealant applied. Significant statistical differences were found when analyzing the presence of fissure sealants related with parents´educational level (<9th grade, OR = 1.56 CI95% = 1.05–2.54), gender (female, OR = 1.86 CI95% = 1.19–2.98), experience of dental pain (yes, OR = 0.62 CI95% = 0.39–0.97) and presence of dental caries (yes, OR = 0.35 CI95% = 0.19–0.65). Conclusions The moderate level of caries prevalence reveals the need of improvement of primary prevention interventions among

  5. Ground fissures in the area of Mavropigi Village (N. Greece): Seismotectonics or mining activity?

    NASA Astrophysics Data System (ADS)

    Kalogirou, Eleni; Tsapanos, Theodoros; Karakostas, Vassilios; Marinos, Vassilios; Chatzipetros, Alexandros

    2014-12-01

    In the beginning of July 2010, a ground fissure was observed in the field near the village of Mavropigi (Northern Greece) and specifically in its NW side. Later on (early September), a second ground fissure was perceived, close and almost parallel to the first one and very close to the limits of the lignite exploitation mine (by the Public Power Corporation, PPC). It was observed that the village of Mavropigi slides away slowly towards the PPC lignite mine. Geological, seismological, as well as geotechnical survey in the field indicated that the phenomenon is related to the coal mining exploitation in the near vicinity of the village rather than to any seismotectonic activity in the surrounding area.

  6. Quality Assessment of Information About Pit and Fissure Sealants in Persian Websites in 2012

    PubMed Central

    Ghasemi, Leila

    2016-01-01

    Objectives: Despite the increasing use of Internet, there is no supervision over the accuracy and quality of the information provided in the web. To deal with this problem, health specialists should take part in planning, publishing and supervision of online health-related information. The aim of this study was to evaluate the quality of information related to pit and fissure sealants in Persian websites. Materials and Methods: In this cross-sectional study, Persian websites providing information about fissure sealants were found using Google search engine. The searched keywords according to the MeSH database were “patient education” and “fissure sealant”. After applying the exclusion criteria, 37 websites out of 500 initial links remained in the study. These websites were evaluated based on a researcher-made checklist. The validity and reliability of the checklist were evaluated and confirmed. Descriptive analysis was applied to report the results of our study using SPSS version 11.5. Results: The average score for the quality of information was 22.46 out of 38. The minimum scores were 16 and 30 and belonged to Pezeshkanemrooz.com and Asa85.blogfa.com , respectively. The results showed that 62.2% of the answers were scored 2–4 and 37.8% were scored 1; therefore, the overall quality of the published content was rated to be moderate for 62.2% and low for 37.8% of the websites. Conclusions: Overall, the quality of information related to fissure sealant provided in Persian websites was good; however, the information given was mostly incomplete and could be improved. The main problems were doubtful credibility and outdated information.

  7. Artificial recharge through a well in fissured carbonate rock, west St. Paul, Minnesota

    USGS Publications Warehouse

    Reeder, Harold O.; Wood, Warren W.; Ehrlich, G.G.; Sun, Ren Jen

    1976-01-01

    The injection test demonstrated that it is hydrologically feasible to recharge the Prairie du Chien Group and the Jordan Sandstone artificially through wells completed in the Prairie du Chien Group. The fissures in the Prairie du Chien Group act as conduits through which water spreads. The water passes into the Jordan Sandstone from the Prairie du Chien over a larger area than it would if it were injected directly into the Jordan.

  8. Dynamics of the 2014 Holuhraun fissure eruption analysed by video monitoring system

    NASA Astrophysics Data System (ADS)

    Witt, Tanja; Walter, Thomas R.

    2015-04-01

    Events on the volcanic system within the axial volcanic zones are linked to plate movements. The spreading and subsequent rifting of the crust take place at the plate boundary and occurs in distinct rifting episodes. These rifting episodes are characterized by earthquakes and volcanic eruptions within the central volcano or along fissures. For the subsurface structure of a volcanic system and the behavior of the magma plumbing system during major rifting episodes two contrasting models exists, (i) vertical feeding by a deep magma source or (ii) lateral feeding through a shallow magma chamber under the central volcano. The ongoing 2014 Holuhraun eruption is providing a unique opportunity to rigorously test the feeding paths of an active fissure eruption. Here we employ video images to analyse the height and velocity variation of the lava fountains at the Holuhraun eruption fissure. On the first day of the eruption we could set up in total five high resolution video cameras. With algorithms of photogrammetry and correlation analysis we interpret the behavior of the lava fountains. Results suggest a significal lateral propagation path of the dynamics of the active vents, and a lateral migration of the peaks and lows of distinct lava fountains. Although the correlation system can change episodically and sporadically, both the frequency of the lava fountains and the eruption and rest time between single fountains remain similar for adjacent lava fountains imply a controlling process in the magma feeder system itself. We interpret the results by a lateral magma and gas flow underlying and feeding the eruption fissure. Systematic recording and analysis of video data hence help to decide which magma plumbing system is more reliable. Additionally, the dataset allows us to compare the eruption behavior to seismic datasets.

  9. 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. PMID:26508410

  10. Resin infiltration of fissure caries with various techniques of pretreatment in vitro.

    PubMed

    Lausch, Julian; Paris, Sebastian; Selje, Timo; Dörfer, Christof E; Meyer-Lueckel, Hendrik

    2015-01-01

    The resin infiltration technique might be used for occlusal caries lesions in order to arrest their progression. This in vitro study evaluated the influence of various modifications of the infiltration technique on the penetration abilities of the infiltrant into occlusal lesions. Extracted human molars and premolars (n = 140) with non-cavitated white spot lesions were randomly allocated to 7 groups. As control, specimens were etched with 15% hydrochloric acid (HCl) gel for 120 s and resin infiltrated for 180 s (Icon; DMG). As modification HCl gel reduced in surface tension and viscosity with and without abrasives was applied using 3 different types of brushes either to oscillate or rub the HCl gel onto the enamel surface. The median maximum lesion depth was 1,232 µm (interquartile range 882-1,513). Compared with the control procedure [23% (16/50)] a higher percentage penetration was observed if the HCl gel was mixed with a small amount of abrasives were rubbed into the fissures using a modified brush with stiff bristles that were adjusted to the fissure relief for either 120 s [100% (64/100)] or 30 s [98% (61/100); p < 0.05; Mann-Whitney test]. All other experimental treatments resulted in penetration results in-between. It can be concluded that the use of an abrasive HCl gel in conjunction with a modified brush mostly enhances resin infiltration into fissure caries lesions. PMID:25427531

  11. Organogenesis of mild ocular coloboma in FLS mice: failure of basement membrane disintegration at optic fissure margins.

    PubMed

    Tsuji, Naho; Kita, Katsutoshi; Ozaki, Kiyokazu; Narama, Isao; Matsuura, Tetsuro

    2012-01-01

    Fatty Liver Shionogi (FLS) mice have been shown to develop a hereditary disorder characterized by localized retinochoroidal defects of the ventral fundus very similar to human typical ocular coloboma without microphthalmia. The objective of this study was to determine when and how the failure of the optic fissure closure occurs, and to clarify the disturbed mechanism of basement membrane disintegration during embryonal stage in FLS mice. Fetuses at day 11.5-15.5 of gestation were obtained from dams of FLS and BALB/c strain of mice. Coronal serial sections through the eye were examined by light and electron microscopy. The sections were followed by observation of the basement membrane using reaction with periodic acid-Schiff (PAS) reagent and immunohistochemical staining with anti-Laminin and anti-Type IV collagen antibodies. Both optic fissure margins closely approached each other up to GD 11.5 in all FLS and BALB/c embryos. The inner and outer layers of the optic cup did not normally fuse at midlenticular levels of the optic fissure in almost 70% of FLS fetuses by GD 15.5, whereas both margins were completely fused in all BALB/c fetuses of the same gestational day. In the FLS fetuses at GD 12.5, rolling on one side of fissure margins and consequent asymmetry were observed at the ventral optic fissure. The basement membrane persisted after the close contact of both sides of the fissure margins during GD 11.5 and 15.5. Ultrastructurally, the basal lamina was not disintegrated and mesenchymal cells intervened between the two neuroepithelial layers, resulting in complete separation of both fissure margins at GD 13.0. It is highly probable that the disturbed basement membrane disintegration right before optic fissure closure causes mild ocular coloboma without microphthalmia in FLS mice. PMID:22182670

  12. An Experimental and Numerical Study on Cracking Behavior of Brittle Sandstone Containing Two Non-coplanar Fissures Under Uniaxial Compression

    NASA Astrophysics Data System (ADS)

    Yang, Sheng-Qi; Tian, Wen-Ling; Huang, Yan-Hua; Ranjith, P. G.; Ju, Yang

    2016-04-01

    To understand the fracture mechanism in all kinds of rock engineering, it is important to investigate the fracture evolution behavior of pre-fissured rock. In this research, we conducted uniaxial compression experiments to evaluate the influence of ligament angle on the strength, deformability, and fracture coalescence behavior of rectangular prismatic specimens (80 × 160 × 30 mm) of brittle sandstone containing two non-coplanar fissures. The experimental results show that the peak strength of sandstone containing two non-coplanar fissures depends on the ligament angle, but the elastic modulus is not closely related to the ligament angle. With the increase of ligament angle, the peak strength decreased at a ligament angle of 60°, before increasing up to our maximum ligament angle of 120°. Crack initiation, propagation, and coalescence were all observed and characterized from the inner and outer tips of pre-existing non-coplanar fissures using photographic monitoring. Based on the results, the sequence of crack evolution in sandstone containing two non-coplanar fissures was analyzed in detail. In order to fully understand the crack evolution mechanism of brittle sandstone, numerical simulations using PFC2D were performed for specimens containing two non-coplanar fissures under uniaxial compression. The results are in good agreement with the experimental results. By analyzing the stress field, the crack evolution mechanism in brittle sandstone containing two non-coplanar fissures under uniaxial compression is revealed. These experimental and numerical results are expected to improve the understanding of the unstable fracture mechanism of fissured rock engineering structures.

  13. Fracturing and Seismicity at the Prestahnúkur Fissure Swarm in the Ultra-Slowly Spreading Western Volcanic Zone, Iceland

    NASA Astrophysics Data System (ADS)

    Hjartardottir, A. R.; Hjaltadottir, S.; Einarsson, P.; Vogfjord, K. S.

    2014-12-01

    Extension across the mid-Atlantic plate boundary in south Iceland is taken up by two parallel zones, the Western and the Eastern Volcanic Zones. Spreading across the western zone is of the order of 1-7 mm/year, qualifying it as an ultra-slow rift. The Prestahnúkur fissure swarm in the Western Volcanic Zone offers an opportunity to study magma-tectonic interaction in an ultra-slow spreading setting. In this study, fractures and faults were mapped in detail from aerial photographs to determine the extent of the fissure swarm. The fissure swarm is about 60 km long and 10 km wide, although its extent to the south is uncertain due to its linkage with the adjacent Hengill fissure swarm. The fissure swarm has both open fractures, indicating postglacial activation, and normal faults with up to 45 m vertical offset. Hyaloclastite ridges („tindars"), produced by subglacial fissure eruptions during the Pleistocene, are found within the fissure swarm, as well as postglacial lava flows. Intermittent seismicity occurs in the area. Earthquakes during the last ~24 years were relocated to study their relation with the surface fractures. Relocation of these events indicate that some of the fractures seen on surface have been activated during these years. The small cumulative seismic moment and slow spreading measured by geodetic methods nevertheless show that no dike intrusions have occurred during this period. Pleistocene tindars and Holocene lavas are clear indications of magmatism, however. We therefore suggest that the Prestahnúkur fissure swarm is mainly formed by diking and rifting during rifting episodes, whereas small scale fracture movements can occur during inter-rifting periods. The present small-scale fracture movements may indicate lack of magma to drive dike intrusions.

  14. 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.

  15. Method for laser drilling subterranean earth formations

    DOEpatents

    Shuck, Lowell Z.

    1976-08-31

    Laser drilling of subterranean earth formations is efficiently accomplished by directing a collimated laser beam into a bore hole in registry with the earth formation and transversely directing the laser beam into the earth formation with a suitable reflector. In accordance with the present invention, the bore hole is highly pressurized with a gas so that as the laser beam penetrates the earth formation the high pressure gas forces the fluids resulting from the drilling operation into fissures and pores surrounding the laser-drilled bore so as to inhibit deleterious occlusion of the laser beam. Also, the laser beam may be dynamically programmed with some time dependent wave form, e.g., pulsed, to thermally shock the earth formation for forming or enlarging fluid-receiving fissures in the bore.

  16. Seismic processes and migration of magma during the Great Tolbachik Fissure Eruption of 1975-1976 and Tolbachik Fissure Eruption of 2012-2013, Kamchatka Peninsula

    NASA Astrophysics Data System (ADS)

    Fedotov, S. A.; Slavina, L. B.; Senyukov, S. L.; Kuchay, M. S.

    2015-12-01

    Seismic and volcanic processes in the area of the northern group of volcanoes (NGV) in Kamchatka Peninsula that accompanied the Great Tolbachik Fissure Eruption (GTFE) of 1975-1976 and the Tolbachik Fissure Eruption (TFE, or "50 let IViS" due to anniversary of the Institute of Volcanology and Seismology, Far East Branch, Russian Academy of Sciences) of 2012-2013 and the seismic activity between these events are considered. The features of evolution of seismic processes of the major NGV volcanoes (Ploskii Tolbachik, Klyuchevskoy, Bezymannyi, and Shiveluch) are revealed. The distribution of earthquakes along depth, their spatial and temporal migration, and the relation of seismic and volcanic activity are discussed. The major features of seismic activity during the GTFE preparation and evolution and a development of earthquake series preceding the origin of the northern and southern breaks are described. The character of seismic activity between the GTFE and TFE is shown. The major peculiarities of evolution of seismic activity preceding and accompanying the TFE are described. The major magma sources and conduits of the NGV volcanoes are identified, as is the existence of a main conduit in the mantle and a common intermediate source for the entire NGV, the depth of which is 25-35 km according to seismic data. The depth of a neutral buoyancy layer below the NGV is 15-20 km and the source of areal volcanism of magnesian basalts northeast of the Klyuchevskoy volcano is located at depth of ~20 km. These data support the major properties of a 2010 geophysical model of magmatic feeding system of the Klyuchevskoy group of volcanoes. The present paper covers a wider NGV area and is based on the real experimental observations.

  17. Land subsidence and earth fissures in south-central and southern Arizona, USA

    NASA Astrophysics Data System (ADS)

    Conway, Brian D.

    2016-05-01

    Land subsidence due to groundwater overdraft has been an ongoing problem in south-central and southern Arizona (USA) since the 1940s. The first earth fissure attributed to excessive groundwater withdrawal was discovered in the early 1950s near Picacho. In some areas of the state, groundwater-level declines of more than 150 m have resulted in extensive land subsidence and earth fissuring. Land subsidence in excess of 5.7 m has been documented in both western metropolitan Phoenix and Eloy. The Arizona Department of Water Resources (ADWR) has been monitoring land subsidence since 2002 using interferometric synthetic aperture radar (InSAR) and since 1998 using a global navigation satellite system (GNSS). The ADWR InSAR program has identified more than 25 individual land subsidence features that cover an area of more than 7,300 km2. Using InSAR data in conjunction with groundwater-level datasets, ADWR is able to monitor land subsidence areas as well as identify areas that may require additional monitoring. One area of particular concern is the Willcox groundwater basin in southeastern Arizona, which is the focus of this paper. The area is experiencing rapid groundwater declines, as much as 32.1 m during 2005-2014 (the largest land subsidence rate in Arizona State—up to 12 cm/year), and a large number of earth fissures. The declining groundwater levels in Arizona are a challenge for both future groundwater availability and mitigating land subsidence associated with these declines. ADWR's InSAR program will continue to be a critical tool for monitoring land subsidence due to excessive groundwater withdrawal.

  18. 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.

  19. Reconstructing recent basaltic fissure eruptions in the Afar Depression, Ethiopia, using satellite imagery

    NASA Astrophysics Data System (ADS)

    Barnie, T. D.; Ferguson, D. J.; Oppenheimer, C.

    2009-12-01

    Since 2005, there have been numerous dike intrusions in the Manda-Hararo rift segment in central Afar, Ethiopia, as part of an on-going rifting event similar to that which occurred at Krafla, Iceland between 1975 and 1984. Two of the dikes have been associated with basaltic fissure eruptions, in August 2007 and in June 2009. A large fissure eruption also occurred in the Erta ‘Ale volcanic range in northern Afar in November 2008, which may be related to the activity further south. These eruptions took place in remote areas and lasted only a few days, making field observation almost impossible. We must therefore rely on the geomorphology and geochemistry of the erupted deposits, and syn-eruption satellite observations of thermally emitted radiance and gas emissions to reconstruct the evolution of these eruptions. Reconstruction of the eruptions is important for i) understanding the relationship between dike intrusion and fissure eruption dynamics ii) understanding the relationship between eruption dynamics and the resulting deposits, iii) interpreting the deposits of pre-historic eruptions from previous rifting events, and iv) estimating the hazard posed to the local population by further activity. In this study we use pre- and post-eruption high resolution ASTER and ALI images to map the morphology of the erupted material, and SEVIRI and MODIS time series of the eruptions to track evolution of the vent dynamics and lava flows. These datasets are augmented by oblique aerial and ground based photographic and FLIR surveys of the cooling lava flows and tephra. ASTER and ALI images are also used to map older erupted materials, which allow us to compare this rifting event with previous events to anticipate future activity.

  20. Ability of Pit and Fissure Sealant-containing Amorphous Calcium Phosphate to inhibit Enamel Demineralization

    PubMed Central

    Owais, Arwa I; Kawaja, Wasan

    2016-01-01

    ABSTRACT Aim: To evaluate the effect of amorphous calcium phosphate (ACP)-containing pit and fissure sealant on inhibition of enamel demineralization in vitro. Materials and methods: Enamel specimens (n = 75) were prepared using freshly extracted noncarious human third molars. Box-shaped cavities (8 × 2 × 2 mm) on the buccal or lingual surfaces were prepared and restored with resin-based sealant (Concise™), ACP-containing sealant (Aegis®) or fluoride-containing sealant (Conseal-F™). The samples were acid challenged in a demineralizing solution of 50 mmol/l lactic acid at pH 5.0 for 4 days. The change in enamel microhardness (ASuH) was calculated. Data were analyzed using one-way analysis of variance (ANOVA) and Tukey’s post hoc test. Results: The mean SuH0 (±SD) (in Vicker’s unit) prior to the acid challenge was: Concise™ (318.83 ± 33.86), Aegis® (331.03 ± 21.52), Conseal-F™ (310.12 ± 34.31). Following the acid challenge, the values dropped in all groups and ASuH (±SD) values were 269.17 ± 47.49, 151.39 ± 23.96 and 175.79 ± 32.39 respectively. Conclusion: The ACP-containing pit and fissure sealant has the potential to inhibit enamel demineralization. How to cite this article: Zawaideh FI, Owais AI, Kawaja W. Ability of pit and fissure sealant-containing amorphous calcium phosphate to inhibit enamel demineralization. Int J Clin Pediatr Dent 2016;9(1):10-14. PMID:27274148

  1. Anal fissure

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    ... cream, if pain interferes with normal bowel movements Petroleum jelly Zinc oxide, 1% hydrocortisone cream, Preparation H, ... is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation ...

  2. Anal Fissure

    MedlinePlus

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  3. Fissured Tongue

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  4. Continuous monitoring of an earth fissure in Chino, California, USA - a management tool

    NASA Astrophysics Data System (ADS)

    Carpenter, M. C.

    2015-11-01

    Continuous measurements of deformation have been made in Chino, California across an earth fissure and nearby unfissured soil since 2011 in two buried, horizontal, 150 mm pipes, 51 m long, which are connected by sealed boxes enclosing vertical posts at mostly 6 m intervals. Horizontal displacements and normal strain are measured in one line using nine end-to-end quartz tubes that are attached to posts and span fissured or unfissured soil. The free ends of the tubes are supported by slings and move relative to the attachment post of the next quartz tube. Linear variable differential transformer (LVDT) sensors measure the relative movements. Five biaxial tilt sensors were also attached to selected posts in that line. Relative vertical movement was measured at nine locations along the line in the second pipe using low-level differential pressure sensors. The second pipe is half full of water giving a free water surface along its length. Data are recorded on a Campbell CR10 using multiplexers. The quartz-tube horizontal extensometers have exhibited more than 3 mm of predominantly elastic opening and closing in response to about 32 m of seasonal drawdown and recovery, respectively, in an observation well 0.8 km to the south. The nearest production well is 1.6 km to the west. The horizontal strain was 5.9 × 10-5 or 30 % of the lowest estimate of strain-at-failure for alluvium. Maximum relative vertical movement was 4.8 mm. Maximum tilt in the fissure zone was 0.09 arcdeg while tilt at a separate sensor 100 m to the east was 0.86 arcdeg, indicating a wider zone of deformation than is spanned by the instrumentation. High correlation of horizontal displacements during drawdown, and especially recovery, with change in effective stress supports differential compaction as the mechanism for earth-fissure movement. The continuous measurements of horizontal strain coupled with water-level fluctuations and vertical borehole extensometry can provide a real-time adaptive management

  5. Tectonics and magma chambers of the recent Tolbachik Fissure Eruption (Kamchatka Peninsula)

    NASA Astrophysics Data System (ADS)

    Ermakov, V. A.; Gontovaya, L. I.; Senyukov, S. L.

    2014-12-01

    Structural-geological, petrological, seismotectonic, and seismotomographic data received in regions of areal volcanism of the south-southwest sector of the Plosky Tolbachik volcano area are considered. The fissure eruption occurring here from November 2012 to the middle of September 2013 was called 50 years of IVS after the 50th anniversary of the Institute of Volcanology and Seismology, Far Eastern Branch, Russian Academy of Sciences. A joint analysis of new and retrospective data allows us to suggest a model for the recent eruption and formulate some problems for future studies and eruption forecasting.

  6. Treating pit-and-fissure caries: a systematic review and network meta-analysis.

    PubMed

    Schwendicke, F; Jäger, A M; Paris, S; Hsu, L Y; Tu, Y K

    2015-04-01

    For shallow or moderately deep pit-and-fissure lesions, various treatment options are available: (1) noninvasive treatments (e.g., fluoride application, antibacterial treatments, oral hygiene advice) avoid any dental hard tissue removal; (2) microinvasive treatments (e.g., sealing) remove only a few micrometers of hard tissues by etching; and minimally invasive methods (e.g., "preventive" resin/sealant restoration) remove carious dentin but avoid sacrificing sound tissues. We aimed at systematically reviewing and comparing these strategies for treating pit-and-fissure lesions in permanent teeth using network meta-analysis. Randomized or nonrandomized clinical trials investigating shallow or moderately deep primary caries lesions in fissured or pitted surfaces were included. We compared the risk of requiring invasive treatments or any retreatments in noninvasive, microinvasive, and minimally invasive treated lesions; untreated lesions were used as controls. Five electronic databases were systematically screened up to September 2013 and cross-referencing performed. Pairwise and network meta-analyses were performed and odds ratios and 95% confidence intervals (CI) calculated. Certainty of estimates was evaluated via GRADE criteria. From a total of 2,214 identified records, 14 studies representing 1,440 patients with 3,551 treated lesions were included. Pairwise meta-analysis found microinvasive and minimally invasive treated lesions to require less invasive retreatments than control lesions (odds ratios [95% confidence intervals]: 0.13 [0.07 to 0.26], 0.13 [0.03 to 0.50], respectively), whereas the estimate for noninvasively treated lesions remained nonsignificant (0.64 [0.39 to 1.06]). These findings were reflected in the strategy ranking stemming from network meta-analysis (first, minimally invasive; second, microinvasive; third, noninvasive). However, microinvasive treatment required significantly more total retreatments (including resealing) than minimally or

  7. [Endotracheal hemorrhage caused by fissuration of the innominate artery during prolonged intubation. Surgical treatment].

    PubMed

    Couraud, L; Hafez, A; Velly, J F

    1984-11-24

    We present our surgical procedure for the control of tracheal haemorrhages due to fissuration of the innominate artery in patients with prolonged tracheal intubation or tracheostomy. Temporary haemostasis and protection of the airways against flooding are ensured by downward advancement of the tube, overinflation of the cuffs and digital pressure if required. The fistula is then located and surgical haemostasis is obtained by resection of the innominate artery away from the infected area. The arterial stumps are covered up for protection against secondary infection. Re-establishment of blood flow is not systematic. Cervicosternotomy is regarded as the incision of choice. No complication was encountered in patients treated by this method. PMID:6239257

  8. A prospective randomized trial comparing stapler and laser techniques for interlobar fissure completion during pulmonary lobectomy.

    PubMed

    Marulli, Giuseppe; Droghetti, Andrea; Di Chiara, Francesco; Calabrese, Francesca; Rebusso, Alessandro; Perissinotto, Egle; Muriana, Giovanni; Rea, Federico

    2013-02-01

    Alveolar air leaks, often resulting from lung tissue traumatization during dissection of fissures, still remain a challenging problem in lung surgery. Several tools and techniques have been used to reduce air leakage, but none was judged ideal. This prospective, randomized trial was designed to evaluate the feasibility, safety, and effectiveness of completion of fissures during pulmonary lobectomy by using a laser system. A standard stapler technique was used for comparison; the primary goal was to reach at least a comparable result. Forty-four patients were enrolled, 22 were treated with standard technique by using staplers (S) and 22 underwent laser (L) dissection. Randomization to one of the two groups was intraoperative after evaluating the presence of incomplete fissure (grade 3-4 following Craig's classification). A Thulium laser 2010 nm (Cyber TM, Quanta System, Italy) was used at power of 40 W. Outcome primary measures were the evaluation and duration of intra- and postoperative air leaks, the rate of complications, and the hospital stay. Air leaks (2.1 ± 4.2 vs 3.6 ± 7.2 days; p = 0.98) and chest tube duration (6.4 ± 4.2 vs 7.5 ± 6.3 days, p = 0.44) were lower in L compared with S group even if these were not statistically significant. Complications (36.4 vs 77.3 %; p = 0.006), hospital stay (6.9 ± 3.8 vs 9.9 ± 6.9 days; p = 0.03), hospitalization costs (5,650 vs 8,147 euros; p = 0.01), and procedure costs (77 % of difference; p < 0.0001) were significantly lower for L group, while operative time was longer (197 ± 34 vs 158 ± 41 min; p = 0.004). The use of laser dissection to prevent postoperative air leaks is effective and comparable with stapler technique. Aero-haemostatic laser properties (by sealing of small blood vessels and checking air leaks) allow a safe application during pulmonary lobectomy in interlobar fissure completion avoiding stapler use. PMID:22526973

  9. A Stress-Induced Permeability Evolution Model for Fissured Porous Media

    NASA Astrophysics Data System (ADS)

    Ma, Jianjun; Wang, Jun

    2016-02-01

    A unified permeability evolution model is proposed to capture the evolution of permeability induced by stress. This model is formulated within a conventional permeability-porosity power function, with special attentions being paid to the effects of shear deformation-induced tortuosity and compaction-induced closure of fissures through a permeability resistance parameter. This model contains a small amount number of parameters, which can be calibrated based on conventional experiments. The proposed model is validated through comparison between model simulation and experimental results for sandstones under a wide range of confining pressures. Good performance demonstrates the capability of the proposed permeability evolution model.

  10. Different scale land subsidence and ground fissure monitoring with multiple InSAR techniques over Fenwei basin, China

    NASA Astrophysics Data System (ADS)

    Zhao, C.; Zhang, Q.; Yang, C.; Zhang, J.; Zhu, W.; Qu, F.; Liu, Y.

    2015-11-01

    Fenwei basin, China, composed by several sub-basins, has been suffering severe geo-hazards in last 60 years, including large scale land subsidence and small scale ground fissure, which caused serious infrastructure damages and property losses. In this paper, we apply different InSAR techniques with different SAR data to monitor these hazards. Firstly, combined small baseline subset (SBAS) InSAR method and persistent scatterers (PS) InSAR method is used to multi-track Envisat ASAR data to retrieve the large scale land subsidence covering entire Fenwei basin, from which different land subsidence magnitudes are analyzed of different sub-basins. Secondly, PS-InSAR method is used to monitor the small scale ground fissure deformation in Yuncheng basin, where different spatial deformation gradient can be clearly discovered. Lastly, different track SAR data are contributed to retrieve two-dimensional deformation in both land subsidence and ground fissure region, Xi'an, China, which can be benefitial to explain the occurrence of ground fissure and the correlation between land subsidence and ground fissure.

  11. Detailed modeling of palpebral fissure and its influence on SAR and temperature rise in human eye under GHz exposures.

    PubMed

    Diao, Yinliang; Leung, Sai-Wing; He, Yaqing; Sun, Weinong; Chan, Kwok-Hung; Siu, Yun-Ming; Kong, Richard

    2016-05-01

    This article investigates variations in specific absorption rate and temperature rise in human eye caused by changes in palpebral fissure, the extent of opening between eyelids, under GHz plane-wave electromagnetic (EM) exposures. Detailed human head models with different palpebral fissure features were developed with a refined spatial resolution of 0.25 mm. These head models were then incorporated into both EM and bio-heat simulations, but using finite-difference time-domain method and finite-difference method, respectively. Maximum temperature rise in lens was found to be 0.8°C under EM exposure at 100 W/m(2) . Results reveal that changes in palpebral fissure would produce a 0.23°C variation in maximum temperature rise in lens. Bioelectromagnetics. 37:256-263, 2016. © 2016 Wiley Periodicals, Inc. PMID:27037717

  12. Understanding the link between circumferential dikes and eruptive fissures around calderas based on numerical and analog models

    NASA Astrophysics Data System (ADS)

    Corbi, Fabio; Rivalta, Eleonora; Pinel, Virginie; Maccaferri, Francesco; Acocella, Valerio

    2016-06-01

    Active calderas are seldom associated with circumferential eruptive fissures, but eroded magmatic complexes reveal widespread circumferential dikes. This suggests that, while the conditions to emplace circumferential dikes are easily met, mechanisms must prevent them from reaching the surface. We explain this discrepancy with experiments of air injection into gelatin shaped as a volcano with caldera. Analog dikes show variable deflection, depending on the competition between overpressure, Pe, and topographic unloading, Pl; when Pl/Pe = 4.8-5.3, the dikes propagate orthogonal to the least compressive stress. Due to the unloading, they become circumferential and stall below the caldera rim; buoyancy is fundamental for the further rise and circumferential fissure development. Numerical models quantitatively constrain the stress orientation within the gelatin, explaining the observed circumferential dikes. Our results explain how dikes propagate below the rim of felsic and mafic calderas, but only in the latter they are prone to feed circumferential fissures.

  13. 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

  14. The link between circumferential dikes and eruptive fissures around calderas: insights from numerical and analog models

    NASA Astrophysics Data System (ADS)

    Corbi, Fabio; Rivalta, Eleonora; Pinel, Virginie; Maccaferri, Francesco; Acocella, Valerio

    2016-04-01

    Active calderas are seldom associated with circumferential eruptive fissures along their rim, but eroded portions of extinct magmatic complexes reveal widespread evidence of circumferential dikes. This discrepancy suggests that, while the conditions to emplace circumferential dikes below volcanoes are easily met, mechanisms must exist to arrest the dikes before they reach the surface. Here we explain this discrepancy with laboratory experiments of air injection into a gelatin medium shaped to mimic a volcanic edifice with caldera. Our models show that the ascending dikes experience a variable degree of deflection, depending on the competition between dike overpressure, Pe, and the forcing induced by the topographic load, Pl. When Pl/Pe = 4.3 - 4.5 the analog dikes proceed almost insensitive to the stress rotation and erupt within the caldera. When Pl/Pe = 4.8 - 5.3 the analog dikes closely propagate orthogonal to the least compressive stress σ3 and stall below the caldera rim in a circumferential arrangement. Progressive buoyancy increase through repeated supply of fluid is fundamental for the occurrence of circumferential fissures. Complementary numerical models explain the observed circumferential arrangement and validate the experiments. These results contribute defining the shallow magma transfer and related hazard assessment within calderas.

  15. 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.

  16. One-year clinical evaluation of a Glass Carbomer fissure sealant, a preliminary study.

    PubMed

    Gorseta, K; Glavina, D; Borzabadi-Farahani, A; Van Duinen, R N; Skrinjaric, I; Hill, R G; Lynch, E

    2014-06-01

    Glass Carbomer is a new generation of restorative material developed from glass-ionomer cements with possibility of gradual mineralization into fluorapatite. The aim of this clinical trial was to investigate the retention of Glass Carbomer fissure sealant after 12 months, in comparison to a commonly used conventional resin-based sealant. Forty-eight teeth in 24 patients [mean (SD) = 8 (2.3) years] with well-delineated fissure morphology were randomly divided into two equal groups and sealed with Bis-GMA resin-based Helioseal F (group A, Ivoclar Vivadent, Liechtenstein) and Glass Carbomer (group B, Glass Carbomer Sealant, Glass Carbomer Products, Leiden, Netherlands) using the split mouth design. Materials were placed and set according to the manufacturer's instructions using a polymerization unit Bluephase 16i (Vivadent, Liechtenstein). Complete sealant retentions in both groups were 100% and 75% after 6 and 12 months of clinical service, respectively. There were there were no secondary caries lesions in both groups after 6 months; two new carious lesions were detected in both groups after 12 months. The Mann-Whitney U test revealed no significant difference between the two groups at both evaluations points (P > 0.05). Glass Carbomer material showed a similar retention rate when compared with a resin-based sealant. Future studies are required to examine the long-term performance of Glass Carbomer sealants. PMID:25134364

  17. Monitoring of land subsidence and ground fissures in Xian, China 2005-2006: Mapped by sar Interferometry

    USGS Publications Warehouse

    Zhao, C.Y.; Zhang, Q.; Ding, X.-L.; Lu, Zhiming; Yang, C.S.; Qi, X.M.

    2009-01-01

    The City of Xian, China, has been experiencing significant land subsidence and ground fissure activities since 1960s, which have brought various severe geohazards including damages to buildings, bridges and other facilities. Monitoring of land subsidence and ground fissure activities can provide useful information for assessing the extent of, and mitigating such geohazards. In order to achieve robust Synthetic Aperture Radar Interferometry (InSAR) results, six interferometric pairs of Envisat ASAR data covering 2005-2006 are collected to analyze the InSAR processing errors firstly, such as temporal and spatial decorrelation error, external DEM error, atmospheric error and unwrapping error. Then the annual subsidence rate during 2005-2006 is calculated by weighted averaging two pairs of D-InSAR results with similar time spanning. Lastly, GPS measurements are applied to calibrate the InSAR results and centimeter precision is achieved. As for the ground fissure monitoring, five InSAR cross-sections are designed to demonstrate the relative subsidence difference across ground fissures. In conclusion, the final InSAR subsidence map during 2005-2006 shows four large subsidence zones in Xian hi-tech zones in western, eastern and southern suburbs of Xian City, among which two subsidence cones are newly detected and two ground fissures are deduced to be extended westward in Yuhuazhai subsidence cone. This study shows that the land subsidence and ground fissures are highly correlated spatially and temporally and both are correlated with hi-tech zone construction in Xian during the year of 2005-2006. ?? Springer-Verlag 2008.

  18. Three QTLs conferring resistance to kernel fissuring in rice (Oryza sativa L.) identified by selective genotyping in two tropical japonica populations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Kernel fissures caused by pre- or post-harvest stresses are the leading cause of breakage among milled rice, causing economic losses for producers, millers, and processors. Being an environmentally sensitive trait, it is difficult to reliably select for rice fissure resistance among breeding progen...

  19. Herpes zoster ophthalmicus presenting as orbital abscess along with superior orbital fissure syndrome: A case report

    PubMed Central

    Lavaju, Poonam; Badhu, Badri Prasad; Shah, Sangeeta

    2015-01-01

    Orbital abscess and superior orbital fissure syndrome (SOFS) are rare manifestations of herpes zoster ophthalmicus. Herein, we report a case of orbital abscess along with SOFS in a 2.5-year-old-male child secondary to herpes zoster infection. He presented with a 5-day history of proptosis and ptosis of the right eye that had been preceded by vesicular eruptions on the right forehead and scalp. Computed tomography scan of the head and orbit showed orbital abscess and right cavernous sinus thrombosis. A diagnosis of orbital abscess with SOFS secondary to herpes infection was made. The condition subsequently improved following antiviral therapy, intravenous vancomycin and amikacin, and oral corticosteroids. PMID:26632131

  20. Mapping radiating graben-fissure systems and pit crater chains on Venus

    NASA Astrophysics Data System (ADS)

    Davey, Sarah

    This study has mapped two types of extensional tectono-magmatic structures including radiating graben-fissure systems (RGFS) in the Idunn Mons and Mielikki Mons study areas, and pit crater chains in Idunn Mons, Themis Regio, Ulfrun Regio, and Ganiki Planitia on Venus. The areas selected to map RGFS host high emissivity anomalies focused on a single volcano and are proposed to reflect younger lava flows which might have occurred as recently as 250 ka. A relative chronology of RGFS is determined using cross-cutting relationships between interacting systems and surface geology. The Idunn Mons high emissivity anomaly is host to the youngest magmatic and volcanic activity, while the Mielikki Mons high emissivity anomaly is not the youngest. Hierarchical clusters of pit crater chains are predominantly focused on RGFS and coronae. It is hypothesized that hierarchical clustering is due to a lithology related variable as lithology may dictate how tensile stress is expressed.

  1. Enamel pretreatment with Er:YAG laser: effects on the microleakage of fissure sealant in fluorosed teeth

    PubMed Central

    Kianimanesh, Nasrin; Shayeghi, Bahareh

    2014-01-01

    Objectives The purpose of this in vitro study was to evaluate the microleakage and penetration of fissure sealant in permanent molar teeth with fluorosis after pretreatment of the occlusal surface. Materials and Methods A total of 120 third molars with mild dental fluorosis were randomly divided into 6 groups (n = 20). The tooth surfaces were sealed with an unfilled resin fissure sealant (FS) material. The experimental groups included: 1) phosphoric acid etching (AE) + FS (control); 2) AE + One-Step Plus (OS, Bisco) + FS; 3) bur + AE + FS; 4) bur + AE + OS + FS; 5) Er:YAG laser + AE + FS; and 6) Er:YAG laser + AE + OS + FS. After thermocycling, the teeth were immersed in 0.5% fuchsin and sectioned. Proportions of mircoleakage (PM) and unfilled area (PUA) were measured by digital microscope. Results Overall, there were significant differences among all groups in the PM (p = 0.00). Group 3 showed the greatest PM, and was significantly different from groups 2 to 6 (p < 0.05). Group 6 showed the lowest PM. Pretreatment with Er:YAG with or without adhesive led to less PM than bur pretreatment. There were no significant differences among groups in PUA. Conclusions Conventional acid etching provided a similar degree of occlusal seal in teeth with fluorosis compared to those pretreated with a bur or Er:YAG laser. Pretreatment of pits and fissures with Er:YAG in teeth with fluorosis may be an alternative method before fissure sealant application. PMID:25110641

  2. 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

  3. Stratigraphy and geochronology of pitfall accumulations in caves and fissures, Bermuda

    NASA Astrophysics Data System (ADS)

    Hearty, Paul J.; Olson, Storrs L.; Kaufman, Darrell S.; Edwards, R. Lawrence; Cheng, Hai

    2004-05-01

    Deep fractures ("fissures") and avens ("skylights") in limestone cave roofs create natural traps for sediments and biota. Fissures fill quickly with surface sediment and organisms soon after opening. Debris cones are formed as materials fall, wash, or drift on air through openings in cave skylights. Such deposits in Admiral's and Grand Canyon Cave, Bermuda contain distinct beds and are composed of mixtures of sediment and charcoal, together with fossils of land snails, crabs, birds, reptiles, and bats. The "pitfall" accumulations were periodically sealed over by calcite flowstone. A stratigraphic record of surface activity and fauna through both glacial and interglacial periods has been preserved. The succession also provides an ideal setting in which to compare several geochronological methods. Calibrated 14C ages on charcoal and shells provide dated horizons at 1600, 12,800, and about 35,000 14C yr BP. Thermal ionization mass spectrometric (TIMS) ages on several flowstone layers constrain the entire sequence in the Admiral's Cave sequence between 126,300±900 yr (Termination II) and historical times. A continuous relative-age record generated by amino acid epimerization (AAE) geochronology ( D-alloisoleucine/ L-isoleucine or aIle/Ile) on the pulmonate land gastropod Poecilozonites verifies the biostratigraphy, reveals a minimal degree of mixing between stratigraphic units, and establishes an independent temporal link between the subterranean and subaerial deposits of Bermuda. This convergence between stratigraphy and geochronology yields a precisely dated succession from the oceanic island of Bermuda, and thus presents a unique opportunity to assess the rates and processes of evolutionary and climate change during that interval.

  4. Shift from magmatic to phreatomagmatic explosion controlled by the evolution of lateral fissure eruption in Suoana Crater, Miyakejima

    NASA Astrophysics Data System (ADS)

    Geshi, Nobuo; Nemeth, Karoly; Noguchi, Rina; Oikawa, Teruki

    2016-04-01

    Combined analysis of the proximal deposit and exposed feeder-diatreme structure of the Suoana Crater of Miyakejima reveals the process of magma-water interaction controlled by the evolution of lateral fissure eruption in a stratovolcanic edifice. The Suoana Crater, an oval maar with 400 x 300 m across is one of the craters of the Suoana-Kazahaya crater chain which is formed during a fissure eruption in the 7th Century. The eruption fissure extends ~3 km from the summit area (~700 m asl) to the lower-flank area (~200m asl). The eruption fissure consists of upper maar-chain (>450 m asl) and lower scora-cone chain. As the wall of the 2000 AD caldera truncated at near the center of the Suoana Crater, the vertical section of the feeder dike - diatreme - maar system of the Suoana Crater is exposed in the caldera wall (Geshi et al., 2011). The ejected materials from the Suoana crater indicate the transition of eruption style from magmatic to phreatomagmatic. The juvenile clasts in the lower half of the deposit exhibit spatter-like shape, indicating the typical deposit from a vigorous fire fountain. Contrary, the juvenile clasts in the upper half are less vesiculated and exhibit cauliflower-shape, indicating the typical phreatomagmatic activity. This transition indicates that the magma-water interaction started at the middle of the eruption. Judging from the ratio of the thickness of the lower and upper parts, the contrast of the content of juvenile clasts, and bulk density of the deposit, the total ejected volume of magma is larger in the lower part compare to the upper part. The transition from magmatic to phreatomagmatic occurred only in the upper half of the eruption fissure, including the Suoana crater, whereas the lower half of the fissure continued dry magmatic eruption throughout their activity. The limited distribution of phreatomagmatic activity can be resulted by the magma extraction from the upper feeder dike system to the lower eruption fissure as it

  5. Comparative study of Ksharasutra suturing and Lord's anal dilatation in the management of Parikartika (chronic fissure-in-ano)

    PubMed Central

    Dudhamal, Tukaram S.; Baghel, Madhav Singh; Bhuyan, Chaturbhuja; Gupta, Sanjay Kumar

    2014-01-01

    Background: Parikartika resembles fissure-in-ano which is very common among all ano-rectal disorders. In Ayurvedic texts, Parikartika is described as a complication of Vamana and Virechana as well as complication of Atisara. Ksharasutra was proved successful in the management of fistula-in-ano, piles, and there is a need to try its efficacy in fissure-in-ano. Aim: To evaluate the role of Ksharasutra suturing (KSS) in fissure bed in chronic fissure-in-ano. Materials and Methods: Total 100 patients of chronic fissure-in-ano were selected and randomly divided into two groups (50 in each group). In group-A, patients were undergone by KSS; while in patients of Group-B Lord's anal dilatation followed by KSS was done under spinal anesthesia. The KSS was done once and after slough out of Ksharasutra, the wound was treated for 4 weeks and assessment of the result was done on the basis of gradation adopted. Results: The pain relief on 14th day in Group-A was 86% while in Group-B 100% was observed. As on 7th day in Group-A, oozing was stopped in 68% patients, while in Group-B, oozing was stopped in 82% patients. On 21st day, Group-B showed more healing (85%) as compared to Group-A (69%). In this study 68% of patients were cured. Conclusion: In Group-B (KSS with Lord's anal dilatation) patients were cured early as compared to patients of Group-A (KSS alone). PMID:25558158

  6. Mechanical Behavior of Brittle Rock-Like Specimens with Pre-existing Fissures Under Uniaxial Loading: Experimental Studies and Particle Mechanics Approach

    NASA Astrophysics Data System (ADS)

    Cao, Ri-hong; Cao, Ping; Lin, Hang; Pu, Cheng-zhi; Ou, Ke

    2016-03-01

    Joints and fissures with similar orientation or characteristics are common in natural rocks; the inclination and density of the fissures affect the mechanical properties and failure mechanism of the rock mass. However, the strength, crack coalescence pattern, and failure mode of rock specimens containing multi-fissures have not been studied comprehensively. In this paper, combining similar material testing and discrete element numerical method (PFC2D), the peak strength and failure characteristics of rock-like materials with multi-fissures are explored. Rock-like specimens were made of cement and sand and pre-existing fissures created by inserting steel shims into cement mortar paste and removing them during curing. The peak strength of multi-fissure specimens depends on the fissure angle α (which is measured counterclockwise from horizontal) and fissure number ( N f). Under uniaxial compressional loading, the peak strength increased with increasing α. The material strength was lowest for α = 25°, and highest for α = 90°. The influence of N f on the peak strength depended on α. For α = 25° and 45°, N f had a strong effect on the peak strength, while for higher α values, especially for the 90° sample, there were no obvious changes in peak strength with different N f. Under uniaxial compression, the coalescence modes between the fissures can be classified into three categories: S-mode, T-mode, and M-mode. Moreover, the failure mode can be classified into four categories: mixed failure, shear failure, stepped path failure, and intact failure. The failure mode of the specimen depends on α and N f. The peak strength and failure modes in the numerically simulated and experimental results are in good agreement.

  7. Analysis of displacements and fissure structures on a slow-moving landslide through very high-resolution orthophoto mosaicing

    NASA Astrophysics Data System (ADS)

    Rothmund, Sabrina; Joswig, Manfred; Niethammer, Uwe; Malet, Jean-Philippe

    2010-05-01

    Very high-resolution multi-temporal images with a ground resolution of a few centimeters allowed to detect and analyze displacements and fissure patterns of the Super-Sauze landslide (Southern French Alps). Images taken by an unmanned aerial vehicle (UAV) during a flight campaign in October 2008 have been used to produce a very high-resolution orthophoto-mosaic of the landslide. In this study, a set of 59 of a total of 1486 images was selected and photogrammetrically processed using different non-parametric rectification approaches (projective transformation, piecewise affine transformation and polynomial transformations of the second and third order). The generated orthophoto-mosaic covers the entire landslide area of 0.09 km² with a ground resolution of 3 to 8 cm. The comparison of this UAV-based orthophoto-mosaic with an orthophotograph from May 2007 (ground resolution of 20 cm) allowed the characterization of the horizontal displacements of the landslide. Displacement vectors were estimated by visually inspecting the images to identify distinct features (rocks, boulders and vegetation patches) in the two orthophotographs. This approach was chosen because of the high dynamics of the landslide and the disadvantageous long period between the repeated image acquisitions. Displacements between 7.1 and 55.4 m in varying directions have been detected and areas of different dynamics could be distinguished for the period between May 2007 and October 2008. Various structures, in particular fissures of different distributions and orientations, could be resolved in the UAV-based orthophoto-mosaic. The similarity of the observed fissures with glacial crevasses is striking and suggests a similar genesis. The identified longitudinal, transverse and cross-shaped fissures are linked to abrupt changes of in-situ crest orientation in the shallow subsurface. The observed shear fissures occur at the lateral boundary of emerging in-situ crests. The fissure genesis could be traced

  8. Geochemistry of the 2012-2013 Tolbachik Fissure eruption (Kamchatka, Russia)

    NASA Astrophysics Data System (ADS)

    Volynets, Anna; Melnikov, Dmitry; Belousov, Alexander; Belousova, Marina; Yakushev, Anton

    2014-05-01

    From November 27th, 2012, until the beginning of September 2013, a fissure eruption at the southern slope of Ploskiy Tolbachik volcano, Kamchatka, produced more than 0.52 km3 of lava (Dvigalo et al., 2014) and covered the area about 36 km2. The eruption was named as "The Institute of Volcanology and Seismology 50th Anniversary Fissure Tolbachik Eruption" (FTE-50). This is a manifestation of the ongoing high activity in Tolbachinskiy Dol (monogenetic zone around Ploskiy Tolbachik stratovolcano), which already produced in Holocene a lava field, covering more than 900 km2. FTE-50 lasted 9 months and exhibited some peculiar features, allowing us to distinguish it as a unique for Tolbachinskiy Dol: seismic activity only in the low energy class during 5 month prior to eruption (Kugaenko et al., 2013), the unusually high discharge rate at the beginning of the eruption (about 400 m3/sec), specific geochemical composition of the erupted lava. The eruption started from two vents, named after eminent Russian volcanologists as Menyailov (upper) and Naboko (lower) vents, and after three days all activity concentrated in the lower (Naboko) vent. All products of FTE-50 are richer in alkalis and TiO2 than previously studied lavas of Tolbachinskiy Dol. After the drastic change in composition at the beginning of the eruption, associated with the shift of the eruption center from the Menyailov to Naboko vent, when silica content dropped up to 2 wt.%, the composition remained practically constant until at least May 2013. Lavas of the Menyailov Vent are more acid than any of the earlier erupted rocks of the monogenetic zone (SiO2 up to 55.35 wt.%). Lavas of the Naboko Vent, at silica content close to the Southern Vent of the Great Fissure Tolbachik Eruption (1975-76) and other alumina-rich basaltic andesites of the Dol (52.5 wt.% in average in Naboko vent lavas vs. 51.8 wt.% in high-Al lavas from Tolb.Dol), have lowered concentrations of Al2O3 (16.3 wt.% vs. 17.1 wt/%), CaO (7.5 wt

  9. 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

  10. Overview of the 2012-13 basaltic fissure eruption of Tolbachik, Kamchatka, Russia

    NASA Astrophysics Data System (ADS)

    Belousov, Alexander; Belousova, Marina; Edwards, Benjamin; Volynetz, Anna; Melnikov, Dmitry; Senyukov, Sergey

    2014-05-01

    On 27 November 2012 a short-lived swarm of shallow (<10 km) earthquakes marked the onset of a new eruption from the Tolbachik volcanic complex, in east-central Kamchatka, Russia. The 3.5-km-long radial eruptive fissure opened on the south flank between 1500-2000 m a.s.l. Lava fountaining from multiple small vents ceased after several days and the eruption continued from vents at the southern end of the fissure. Almost continuous lava fountains up to 200 m high issued from a small lava lake located inside the broad, open crater of the largest cinder cone. While explosive activity was rather mild, initial discharge of lava was very high (up to 400 m3/s) and by the end of December 'a'a lava flows had travelled up to 17 km from the vent. SiO2 concentrations for the plagioclase-phyric lava were 54 wt.%, but then decreased to 52 wt.%. In January 2013 lava was transported through a system of lava tubes 1 km long and up to 5 m wide. From tube exit points it propagated in the form of channelized lava streams (velocities 1-3 m/s; discharge rates 30-50 m3/s); on lower slopes of the volcano it propagated mostly as 'a'a flows. Lava channels were frequently dammed by floating clinker and accretionary lava balls, which caused flooding of proximal areas by ropy/shelly/slabby pahoehoe lavas. Locally small volumes of lava were extruded through the upper surfaces and lateral levees of 'a'a lava to form very slowly inflating entrail pahoehoe lava lobes. Starting in mid-February the average intensity of the eruption gradually declined, with sporadic bursts in February and April. By May discharge rates of lava had decreased to approximately 15 m3/s and most of lava started to flow as entrail pahoehoe. By the beginning of June the volume of erupted products (dominantly lavas) reached 0.52km3. The effusion of lava continued until the end of August, when the lava lake in the crater of the active cinder cone became inactive. Weak strombolian outbursts from 1-3 small vents on the bottom of

  11. Influence of Laser Irradiation on Pits and Fissures: An In Situ Study

    PubMed Central

    Correa–Afonso, Alessandra M; Pécora, Jesus D

    2013-01-01

    Abstract Objective: The aim of this in situ study was to analyze the influence of the Er:YAG, Nd:YAG, and CO2 lasers on the enamel acid resistance of pits and fissures. Background data: The laser tissue interaction has been studied as a method of preventing occlusal caries. Methods: Thirteen volunteers wore palatal acrylic appliances containing human occlusal enamel blocks that were divided into four groups (G1, control; G2, Er:YAG; G3, Nd:YAG; G4, CO2). Each palatal acrylic appliance was used in the four studied groups and was used for 14 consecutive days. A sucrose solution was applied to the specimens six times per day. The specimens were then sectioned in half, and a microhardness test was applied. The other halves were analyzed using polarized light microscopy to measure the caries-like lesion areas, and a morphological analysis was conducted using a scanning electron microscope (SEM). Results: For the statistical analysis of the data obtained from the microhardness test (Knoop hardness number. [KHN]) (α=5%), Fisher's exact test was performed, and the group means were as follows: G1, 247±71; G2, 258±70; G3, 272±73; and G4, 298±56. The results demonstrated that the control group was significantly different from G3 and G4, which presented higher microhardness values. The Wilcoxon signed-rank test was used to analyze the data obtained from the caries-lesion area measurements (mm2) (α=5%) (G1, 0.01±1.08; G2, 0.13±0.18; G3, 0.05±0.17; and G4, 0.09±0.22). The results no showed significant differences among the groups in this analysis. Conclusions: Based on the results from the present study, it may be concluded that the CO2 and Nd:YAG lasers increased the enamel acid resistance in pits and fissures. PMID:23336742

  12. Argon laser curing of fluoride-releasing pit and fissure sealant: in vitro caries development.

    PubMed

    Westerman, G; Hicks, J; Flaitz, C

    2000-01-01

    The purpose of this study was to compare the effect of argon laser polymerization of a visible-light-cured, fluoride-releasing pit and fissure sealant on caries development in vitro. A total of twelve caries-free premolar and molar teeth was selected, and underwent a fluoride-free prophylaxis and soft tissue debridement. Cavity preparations were placed in buccal and lingual surfaces. Lingual cavity preparations were filled with the fluoride-releasing sealant (UltraSealXTplus, Ultradent) and visible light cured per the manufacturer's recommendation. Buccal preparations were filled with the fluoride-releasing sealant and argon laser cured (231 mW, 12 J/cm2 for 10 seconds). Following sealant placement, the teeth were sectioned into buccal and lingual halves. An acid-resistant varnish was placed leaving a 1 mm rim of exposed surface enamel adjacent to the sealant. The specimens were then thermocycled in synthetic saliva (500 cycles, 5 to 50 degrees C). In vitro caries lesions were formed (2.2 mM Ca, 2.2 mM PO4, 50 mM acetic acid, 5 ppm fluoride, pH 3.95). Longitudinal sections (five sections per tooth half) were obtained and evaluated by polarized light microscopy for mean outer surface lesion depths and frequency of wall lesions. Mean primary surface (outer) lesion depth was significantly decreased (ANOVA, DMR, P < .05) for the fluoride-releasing sealant with argon laser polymerization (152 +/- 16 um) when compared with visible light curing (211 +/- 23 um). Likewise, wall lesion frequency was substantially reduced for the argon laser polymerized sealants (17 percent) when compared with that for the visible light polymerized sealants (24 percent, ANOVA, DMR, P < .05). Argon laser polymerization of a fluoride-releasing pit and fissure sealant improved caries resistance markedly in the surface enamel adjacent to the sealant material. Argon laser curing enhanced the caries protective ability of the sealant along the enamel-resin cavosurface, as noted by a decrease in wall

  13. The 'Jack Stone' or 'Mercedes Benz' sign--anew theory to explain the presence of gas within fissures in gallstones.

    PubMed

    Wright, F W

    1977-07-01

    Gas within clefts of fissures in gallstones is not a very common finding, but when it occurs is, characteristic and indicates the presence of one or more calculi. It closely resembles the appearance of a 'Jack Stone' but has previously been termed the 'Mercedes Benz' sign. Only a few cases have previously been recognised in the U.K. Most reported cases have been associated with biliary colic or cholecystitis. Various theories have been put forward to explain the presence of gas, but the author believes that the gas is released from solution by negative pressure within cholesterol stones undergoing internal fissuring due to their crystalline structure, i.e. the gas is released from solution from the small amount of fluid trapped in the calculus, in the same way that gas may be 'pulled' out of solution in a joint, a degenerate intervertebral disc or the fibro-cartilage of the symphysis pubis. PMID:872516

  14. 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.

  15. Chabazite in spodumene-bearing Alpine-type fissure veins from Hiddenite, North Carolina, USA

    NASA Astrophysics Data System (ADS)

    Wise, Michael A.

    2009-07-01

    Alpine-type fissure vein mineralization in the Hiddenite area of western North Carolina, USA consists mostly of quartz, but locally contains Cr-bearing beryl (emerald) or Cr-bearing spodumene (hiddenite). These gem minerals occur in mineral-lined cavities and may be accompanied by euhedral crystals of quartz, calcite, muscovite, rutile, albite, pyrite, siderite and dolomite. Chabazite-Ca occurs as a late stage phase in spodumene-bearing veins, but is absent in emerald-bearing veins. Chabazite-Ca occurs as simple penetrating twins of pseudocubic rhombohedra and as the lens-shaped variety, phacolite. Chabazite-Ca from Hiddenite contains minor amounts of Na, Mg, Fe and K. Phacolitic chabazite-Ca shows Fe-enriched but Mg-depleted cores relative to the rims. Chemical zoning is absent in rhombohedral chabazite. The Hiddenite chabazite apparently precipitated under low temperature (< 250°C) and low pressure (< 2 kbar) conditions during the waning stages of crystallization of an alkaline hydrothermal fluid.

  16. An Experimental Study of the Fracture Coalescence Behaviour of Brittle Sandstone Specimens Containing Three Fissures

    NASA Astrophysics Data System (ADS)

    Yang, S. Q.; Yang, D. S.; Jing, H. W.; Li, Y. H.; Wang, S. Y.

    2012-07-01

    To analyse the fracture coalescence behaviour of rock, rectangular prismatic sandstone specimens (80 × 160 × 30 mm in size) containing three fissures were tested under uniaxial compression. The strength and deformation behaviours of the specimens are first analysed by investigating the effects of the ligament angle β2 on the peak strength, peak strain and crack initiation stress of the specimens. To confirm the sequence of crack coalescence, a photographic monitoring technique is used throughout the entire period of deformation. Based on the results, the relationship between the real-time crack coalescence process and the axial stress-strain curve of brittle sandstone specimens is also developed, and this relationship can be used to evaluate the macroscopic deformation characteristics of pre-cracked rock. The equivalent strain evolution fields of the specimen, with α = β1 = 45° and β2 = 90°, are obtained using the digital image correlation technique and show good agreement with the experimental results of pre-cracked brittle sandstone. These experimental results are expected to improve the understanding of fracture mechanisms and be used in rock engineering with intermittent structures, such as deep underground excavated tunnels.

  17. Sylvian fissure and parietal anatomy in children with autism spectrum disorder.

    PubMed

    Knaus, Tracey A; Tager-Flusberg, Helen; Foundas, Anne L

    2012-01-01

    Autism spectrum disorder (ASD) is characterized by deficits in social functioning and language and communication, with restricted interests or stereotyped behaviors. Anatomical differences have been found in the parietal cortex in children with ASD, but parietal subregions and associations between Sylvian fissure (SF) and parietal anatomy have not been explored. In this study, SF length and anterior and posterior parietal volumes were measured on MRI in 30 right-handed boys with ASD and 30 right-handed typically developing boys (7-14 years), matched on age and non-verbal IQ. There was leftward SF and anterior parietal asymmetry, and rightward posterior parietal asymmetry, across groups. There were associations between SF and parietal asymmetries, with slight group differences. Typical SF asymmetry was associated with typical anterior and posterior parietal asymmetry, in both groups. In the atypical SF asymmetry group, controls had atypical parietal asymmetry, whereas in ASD there were more equal numbers of individuals with typical as atypical anterior parietal asymmetry. We did not find significant anatomical-behavioral associations. Our findings of more individuals in the ASD group having a dissociation between cortical asymmetries warrants further investigation of these subgroups and emphasizes the importance of investigating anatomical relationships in addition to group differences in individual regions. PMID:22713374

  18. Analysis of anticaries potential of pit and fissures sealants containing amorphous calcium phosphate using synchrotron microtomography.

    PubMed

    Delben, A C B; Cannon, M; Vieira, A E M; Basso, M D; Danelon, M; Santo, M R E; Stock, S R; Xiao, X; De Carlo, F

    2015-01-01

    The aim of this study was to analyze the anticaries potential of pit and fissure sealants containing amorphous calcium phosphate (ACP) by synchrotron microtomography. Bovine enamel blocks (4×4 mm; n=50) were selected through surface hardness (Knoop) analysis. Slabs were obtained through cross-sections taken 1 mm from the border of the enamel. Five indentations, spaced 100 μm apart, were made 300 μm from the border. Ten specimens were prepared for each tested material (Ultraseal XT plus TM, Aegis, Embrace, Vitremer and Experimental Sealant). The materials were randomly attached to the sectioned surfaces of the enamel blocks and fixed with sticky wax. The specimens were submitted to pH cycling. After that, the surface hardness (SH1) was determined, and the blocks were submitted to synchrotron microcomputed tomography analysis to calculate the mineral concentration (ΔgHAp cm(-3)) at different areas of the enamel. The comparison between the SH1 and ΔgHAp cm(-3) showed a correlation for all groups (r=0.840; p<0.001). The fluoride groups presented positive values of ΔgHAp cm(-3), indicating a mineral gain that was observed mainly in the outer part of the enamel. The ACP showed mineral loss in the outer enamel compared with fluoride groups, although it inhibited the demineralization in the deeper areas of enamel. The combination of two remineralizing agents (fluoride and ACP) was highly effective in preventing demineralization. PMID:25268042

  19. Caries-inhibiting effect of chlorhexidine varnish in pits and fissures.

    PubMed

    Zhang, Q; van 't Hof, M A; Truin, G J; Bronkhorst, E M; van Palenstein Helderman, W H

    2006-05-01

    Evidence regarding the caries-inhibiting effect of chlorhexidine varnish is inconclusive. This study investigated the caries-inhibiting effect of the varnish EC40 on pits and fissures of first permanent molars. A two-year randomized controlled trial was carried out among 461 six- to seven-year-old children. In a split-mouth design, one group of molars received EC40 at baseline, 6, 12, and 18 months, and another group at baseline, 3, 12, and 15 months. Control molars did not receive EC40. Adherence to the treatment protocol was good. The dropout rate was 17%. Blinded examiners performed dental examinations. The caries-inhibiting effects of the two EC40 application schemes were comparable. The prevented fraction of caries was 25% (95%CI, 1%, 49%, p = 0.04) after 2 years and 9% (95%CI, -11%, 29%, p = 0.20) one year after termination of the trial, suggesting a short-term benefit from the use of EC40. The efficiency of EC40 is questionable in low-caries-incidence child populations. PMID:16632763

  20. Distortion of the anterior part of the interhemispheric fissure: significance and implications for prenatal diagnosis.

    PubMed

    Vinurel, N; Van Nieuwenhuyse, A; Cagneaux, M; Garel, C; Quarello, E; Brasseur, M; Picone, O; Ferry, M; Gaucherand, P; des Portes, V; Guibaud, L

    2014-03-01

    In order to illustrate the significance of a new anatomical finding, distortion of the interhemispheric fissure (DIHF) associated with impacted medial borders of the frontal lobes, we report a retrospective observational study of 13 fetuses in which DIHF was identified on prenatal imaging. In 10 cases there were associated anatomical anomalies, including mainly midline anomalies (syntelencephaly (n=2), lobar holoprosencephaly (n=1), Aicardi syndrome (n=2)), but also schizencephaly (n=1), cortical dysplasia (n=1) and more complex cerebral malformations (n=3), including neural tube defect in two cases. Chromosomal anomaly was identified in two cases, including 6p deletion in a case without associated central nervous system anomalies and a complex mosaicism in one of the cases with syntelencephaly. In two cases, the finding was apparently isolated on both pre- and postnatal imaging, and the children were doing well at follow-up, aged 4 and 5 years. The presence of DIHF on prenatal imaging may help in the diagnosis of cerebral anomalies, especially those involving the midline. If DIHF is apparently isolated on prenatal ultrasound, magnetic resonance imaging is recommended for careful analysis of gyration and midline, especially optic and olfactory structures. Karyotyping is also recommended. PMID:23640781

  1. Voxelized Model of Brain Infusion That Accounts for Small Feature Fissures: Comparison With Magnetic Resonance Tracer Studies.

    PubMed

    Dai, Wei; Astary, Garrett W; Kasinadhuni, Aditya K; Carney, Paul R; Mareci, Thomas H; Sarntinoranont, Malisa

    2016-05-01

    Convection enhanced delivery (CED) is a promising novel technology to treat neural diseases, as it can transport macromolecular therapeutic agents greater distances through tissue by direct infusion. To minimize off-target delivery, our group has developed 3D computational transport models to predict infusion flow fields and tracer distributions based on magnetic resonance (MR) diffusion tensor imaging data sets. To improve the accuracy of our voxelized models, generalized anisotropy (GA), a scalar measure of a higher order diffusion tensor obtained from high angular resolution diffusion imaging (HARDI) was used to improve tissue segmentation within complex tissue regions of the hippocampus by capturing small feature fissures. Simulations were conducted to reveal the effect of these fissures and cerebrospinal fluid (CSF) boundaries on CED tracer diversion and mistargeting. Sensitivity analysis was also conducted to determine the effect of dorsal and ventral hippocampal infusion sites and tissue transport properties on drug delivery. Predicted CED tissue concentrations from this model are then compared with experimentally measured MR concentration profiles. This allowed for more quantitative comparison between model predictions and MR measurement. Simulations were able to capture infusate diversion into fissures and other CSF spaces which is a major source of CED mistargeting. Such knowledge is important for proper surgical planning. PMID:26833078

  2. Effect of topical applications of a chlorhexidine/thymol-containing varnish on fissure caries assessed by laser fluorescence.

    PubMed

    Sköld-Larsson, Kerstin; Fornell, Ann-Charlott; Lussi, Adrian; Twetman, Svante

    2004-12-01

    The aim of this study was to monitor the effect of an antibacterial varnish using the readings of a caries-detecting device (DIAGNOdent) in fissures of young permanent molars. The material consisted of 32 healthy patients with a mean age of 14.1 years undergoing orthodontic treatment with fixed appliances. The inclusion criteria were presence of one homologous pair of 2nd upper or lower molars with clinically intact occlusal surfaces. A split-mouth study design was used in which the fissures were treated with either an antibacterial chlorhexidine/thymol-containing varnish or a placebo varnish every 6th week. The follow-up period was 42 weeks and laser fluorescence (LF) readings were carried out every 12th week. The mean LF values increased significantly (P < 0.05) after 24, 36, and 48 weeks compared to baseline following the placebo treatments but not after treatment with the active antibacterial varnish. During the study period, micro-cavities were diagnosed in two test-treated and five placebo-treated teeth. In conclusion, the results reinforce previous findings that frequent applications of a chlorhexidine/thymol-containing dental varnish might have a protective role in fissures of young permanent molars and that this could be monitored with a chair-side caries detecting LF device. PMID:15848978

  3. Morphologic Study of Superior Temporal Sulcus-Amygdaloid Body and Lateral Fissure-Amygdaloid Body Surgical Approach by Using Magnetic Resonance Imaging Volume Rendering.

    PubMed

    Qu, Yuan; Ren, Bichen; Chang, Xiaoyu; Zhang, Jinnan; Li, Youqiong; Duan, Haobo; Cheng, Kailiang; Wang, Jincheng

    2016-01-01

    In this research, 83 patients were measured by magnetic resonance imaging volume rendering technique. The authors acquired the curve length of the superior temporal sulcus and the lateral fissure on the cerebral hemisphere, the shortest distance from the superior temporal sulcus and the lateral fissure to the center of amygdaloid body separately, the vertical diameter, the transversal diameter, and the anteroposterior diameter of the amygdaloid body and the 2 approach angles between the median sagittal plane and the shortest segment from the superior temporal sulcus to the center of amygdaloid body and the shortest segment from lateral fissure to the center of the amygdaloid body. At the same time, we preliminarily oriented the 2 points of the superior temporal sulcus and the lateral fissure, which are closest to the center of amygdaloid body, aimed at finding out the best entrance points of surgical approach through the superior temporal sulcus and the lateral fissure to the amygdaloid body and reducing the damage to the nerve fibers or blood vessels during the operation. The results indicate that the point at the front side 1/4 of the superior temporal sulcus may be the ideal surgical approach entrance point and the point at the front side 1/3 of the lateral fissure. There is no difference between 2 cerebral hemispheres (P < 0.05). PMID:26674919

  4. Effect of Cervitec on mutans streptococci in plaque and on caries formation on occlusal fissures of erupting permanent molars.

    PubMed

    Araujo, A M P G; Naspitz, G M C C; Chelotti, A; Cai, S

    2002-01-01

    The aim of this study was to evaluate the effect of Cervitec on the abundance of mutans streptococci (MS) in occlusal dental plaque and on 2-year caries increment of partly erupting first permanent molars. Sixteen healthy schoolchildren aged 6-8 years, with at least 2 sound contralateral partly erupted permanent molars, received diet counselling and daily parental supervised toothbrushing with a fluoride dentifrice. Stimulated saliva samples were collected at baseline and after 1 year to evaluate MS levels. In a split-mouth design, Cervitec varnish was applied to one of the teeth at baseline and after 3 and 6 months, while the other tooth in the same jaw was a control. At the 9-month follow-up the teeth were in occlusal contact. At this time, varnish was not applied. At 3 and 6 months after the first application of varnish a significant suppression of MS was observed in plaque. Caries investigations, performed at baseline and every 3 months during the 2 years after the start of the study, showed that all the teeth treated with the varnish were free of caries after 2 years, whereas 8/16 control teeth developed incipient caries. In conclusion, our results suggest that treatment with Cervitec reduces MS in plaque on erupting permanent molars and can lead to a significant decrease in caries incidence. PMID:12399699

  5. Recrystallized Granite Surface Fissures Of The Wasatch Range, Produced Not Later Than 1/4 Billion Years Ago

    NASA Astrophysics Data System (ADS)

    McDonald, Keith L.

    2000-05-01

    Our studies of numerous recrystallized fissures in 4 granite plutons of Wasatch Range, namely, Mount Tuscarora-Wolverine-Millicent,^1,6,7 Bonanza Peak-Midway,^2 Little Cottonwood Canyon and Ferguson Canyon plutons, all of which formed magma chambers reaching Earth-atmosphere interface, establish that they resulted from high thermal gradients rather than passages of earthquake waves. Magma chambers formed, solidified during Permo-Caroniferous Ice Age(roughly, 1/3...1/4 billion yr ago, a time interval preceding period of extrusion of Rocky Mountains, 10^8 yr ago), and while fluid, belched lava flows^5 extending over its reservoir walls to run hundred of meters. We have shown how the magma melts, dilutes and replaces overlying metamorphic rock^7 to reach Earth's surface so that a pluton containing large amounts of dross(Fe-ores, etc.) had a short fluid lifetime. We also described how offshoots from a long-running main fissure form acute angles with that fissure.^3 Such recrystallized fissures, reaching depths of perhaps 100 m, have initial fractures near time of solidification of their uppermost portion of magma chamber while still hot(<= 1600^oF), a time when max. stresses occur near granite surface due to high thermal gradients, owing to snow coverage, cold water contacts due to rain, stream flow over granite surface, partial coverage by ocean, etc., wherever heat sinks might occur, during P-C ice age--when region of Wasatch Range existed at sea level, Salt Lake Valley being covered entirely by ocean water and region east of Wasatch Bouleuard rising gently above Pacific Ocean to elevations of possibly 500-1000 ft, say, at a distance of 10-15 mi to east. This fact is implied by Chinese Wall of white limestone on Grandeur Peak, unequivocally, and similarly another in Neff's Canyon running e. from n. ridge of 9200 ft. saddle-summit, as well as a dozen other ancient calcified stream beds emptying into ocean to w., in Salt Lake Valley. This existed prior to regional

  6. 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

  7. Measurements of the gas emission from Holuhraun volcanic fissure eruption on Iceland, using Scanning DOAS instruments

    NASA Astrophysics Data System (ADS)

    Galle, Bo; Pfeffer, Melissa; Arellano, Santiago; Bergsson, Baldur; Conde, Vladimir; Barsotti, Sara; Stefansdottir, Gerdur; Ingvarsson, Thorgils; Bergsson, Bergur; Weber, Konradin

    2016-04-01

    On 31 August 2014 a volcanic fissure eruption started at Holuhraun on Iceland. The eruption lasted for 6 months and was by far the strongest source of sulfur dioxide in Europe over the last 230 years, with sustained emission rates exceeding 100 000 ton/day. This gas emission severely affected people within Iceland. Under the scope of the EU-project FUTUREVOLC, a project with 3.5 years duration, aiming at making Iceland a supersite for volcanological research as a European contribution to GEO, a version of the Scanning DOAS instrument that is adapted to high latitudes with low UV radiation and severe meteorological conditions was developed. Since the first day of the eruption several of these novel instruments were monitoring the SO2 emission from the eruption. A lot of work was needed to sustain this operation during the winter at a very remote site and under severe field conditions. At the same time the very high concentrations in the gas plume, in combination with bad meteorological conditions has required the development of novel methods to derive reliable flux estimates. A simple approach to make a first order correction for atmospheric scattering has been applied, as well as filtering of the dataset to remove the data most affected by scattering. Substantial work has also been made to obtain realistic information on plume height and wind speed. The data from these instruments are the only sustained ground-based measurements of this important gas emission event. In this presentation we will discuss the instrumental issues and evaluation procedures and present the latest version of the emission estimates made from our measurements.

  8. Genetic susceptibility to dental caries on pit and fissure and smooth surfaces.

    PubMed

    Shaffer, J R; Wang, X; Desensi, R S; Wendell, S; Weyant, R J; Cuenco, K T; Crout, R; McNeil, D W; Marazita, M L

    2012-01-01

    Carious lesions are distributed nonuniformly across tooth surfaces of the complete dentition, suggesting that the effects of risk factors may be surface-specific. Whether genes differentially affect caries risk across tooth surfaces is unknown. We investigated the role of genetics on two classes of tooth surfaces, pit and fissure surfaces (PFS) and smooth surfaces (SMS), in more than 2,600 subjects from 740 families. Participants were examined for surface-level evidence of dental caries, and caries scores for permanent and/or primary teeth were generated separately for PFS and SMS. Heritability estimates (h(2), i.e. the proportion of trait variation due to genes) of PFS and SMS caries scores were obtained using likelihood methods. The genetic correlations between PFS and SMS caries scores were calculated to assess the degree to which traits covary due to common genetic effects. Overall, the heritability of caries scores was similar for PFS (h(2) = 19-53%; p < 0.001) and SMS (h(2) = 17-42%; p < 0.001). Heritability of caries scores for both PFS and SMS in the primary dentition was greater than in the permanent dentition and total dentition. With one exception, the genetic correlation between PFS and SMS caries scores was not significantly different from 100%, indicating that (mostly) common genes are involved in the risk of caries for both surface types. Genetic correlation for the primary dentition dfs (decay + filled surfaces) was significantly less than 100% (p < 0.001), indicating that genetic factors may exert differential effects on caries risk in PFS versus SMS in the primary dentition. PMID:22286298

  9. Effects of sealant, viscosity, and bonding agents on microleakage of fissure sealants: An in vitro study

    PubMed Central

    Mehrabkhani, Maryam; Mazhari, Fatemeh; Sadeghi, Samaneh; Ebrahimi, Masoumeh

    2015-01-01

    Objective: The aim of this study was to evaluate the effects of enamel or dentin bonding agent (DBA) and sealant viscosity on sealant microleakage. Materials and Methods: Sixty extracted human premolars were randomly divided into two equal groups (based on sealant viscosity) and each group was divided into three subgroups of 10 teeth. Group 1 (low viscosity sealant, Seal-Rite, Pulpdent, USA with 7.7% filler): Prophylaxis, enameloplasty, etching of occlusal surfaces with 38% of phosphoric acid gel, rinsing and drying, followed by (1) enamel bonding agent (EBA) (Margin Bond, Coltène/Whaledent AG) or (2) DBA (Excite, Ivoclar Vivadent AG, Liechtenstein) or (3) no bonding (NB) prior to sealant application. In Group 2, similar procedures were performed except for applying a high viscosity sealant (Seal-Rite, Pulpdent, The USA with 34.4% filler). Specimens were thermocycled and then immersed in a 0.5% basic fuchsine solution for 24 h next, buccolingual slices of samples were scored under a stereomicroscope. The Kruskal–Wallis and Mann–Whitney U-tests were used for data analysis. Results: There was no significant difference between DBA, EBA, and NB subgroups in the microleakage scores in both groups. Low viscosity sealant had a lower microleakage than the high viscosity sealant in both DBA (P = 0.002) and NB (P = 0.041) subgroups. Conclusion: The results indicated that the use of low viscosity sealant reduced the microleakage of pit and fissure sealants. However, the use of a bonding agent before sealant placement didn’t affect the microleakage. PMID:26929696

  10. Characterisation and microleakage of a new hydrophilic fissure sealant - UltraSeal XT® hydro™

    PubMed Central

    GÜÇLÜ, Zeynep A.; DÖNMEZ, Nazmiye; HURT, Andrew P.; COLEMAN, Nichola J.

    2016-01-01

    ABSTRACT Objectives The aim of this study was to characterise the new hydrophilic fissure sealant, UltraSeal XT® hydro™ (Ultradent Products, USA), and to investigate its in vitro resistance to microleakage after placement on conventionally acid etched and sequentially lased and acid etched molars. Material and Methods The sealant was characterised by Fourier transform infra-red spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and Vickers indentation test. Occlusal surfaces of extracted human molars were either conventionally acid etched (n=10), or sequentially acid etched and laser irradiated (n=10). UltraSeal XT® hydro™ was applied to both groups of teeth which were then subjected to 2,500 thermocycles between 5 and 55°C prior to microleakage assessment by fuchsin dye penetration. Results UltraSeal XT® hydro™ is an acrylate-based sealant that achieved a degree of conversion of 50.6±2.2% and a Vickers microhardness of 24.2±1.5 under standard light curing (1,000 mWcm-2 for 20 s). Fluoride ion release is negligible within a 14-day period. SEM and EDX analyses indicated that the sealant comprises irregular submicron and nano-sized silicon-, barium-, and aluminium-bearing filler phases embedded in a ductile matrix. Laser preconditioning was found to significantly reduce microleakage (Mann-Whitney U test, p<0.001). The lased teeth presented enhanced surface roughness on a 50 to 100 μm scale that caused the segregation and concentration of the filler particles at the enamel-sealant interface. Conclusion Laser preconditioning significantly decreased microleakage and increased enamel surface roughness, which caused zoning of the filler particles at the enamel-sealant interface. PMID:27556205

  11. Stratigraphy, paleoenvironment and emplacement mechanisms of the Koko fissure craters, O'ahu, Hawai'i

    NASA Astrophysics Data System (ADS)

    Skilling, I. P.; Bluth, J.; Simoneau, E.

    2011-12-01

    The Koko fissure craters are aligned and nested basanitic tuff cones and rings at the SE corner of O'ahu, Hawai'i. There are no published studies of their stratigraphy, emplacement mechanisms or depositional paleoenvironments. This study focuses on a tuff cone complex (Koko Crater) and a younger adjacent nested tuff ring (Hanauma Bay). A detailed stratigraphy with logged sections for both Koko Crater and the Hanauma Bay craters are presented and discussed. Koko Crater is dominated by wet fallout deposits on steep proximal slopes, commonly resedimented by hot (vesiculated) and cold (unvesiculated) debris flows, slumps and slides, but with an increasing percentage of wet (low temperature) low concentration PDC deposits preserved in the shallowly-dipping flanking apron deposits, and in the uppermost proximal deposits. At least two earlier cone or ring rims are preserved along its southern margin. The deposits of Hanauma Bay overlie the Koko deposits and are dominated by a mix of wet low concentration PDC, wet fallout and synchronous PDC, and fallout deposits in proximal settings, and by low concentration, probably drier, PDC deposits in more distal settings. The Hanauma Bay rings were emplaced before the Koko Crater tephra was consolidated, as steep-sided rills incised into Koko tephra are locally filled with tephra of mixed Koko and Hanauma sources. The onset of Hanauma Bay eruptions is marked by a horizon that is very rich in rounded coral sand clasts. Discontinuous horizons and lenses of coral block fallout are also very common in the Hanauma tephra. Coral sand is absent and coral blocks are much rarer in the Koko tephra. These observations, and probably also the dominance of wet fallout at Koko, imply that Koko was erupted in deeper water than the nearshore coral beach environment of the Hanauma rings. A faster rate of water recharge into the conduit in deeper open water is probably the most important factor in the generation of a cone rather than a ring at this

  12. Earth-Fissure Movements Associated with Fluctuations in Ground-Water Levels near the Picacho Mountains, South-Central Arizona, 1980-84

    USGS Publications Warehouse

    Carpenter, M.C.

    1993-01-01

    The Picacho earth fissure transects subsiding alluvial sediments near the east periphery of the Picacho basin in south-central Arizona. The basin has undergone land subsidence of as much as 3.8 meters since the 1930's owing to compaction of the aquifer system in response to ground-water-Ievel declines that have exceeded 100 meters. The fissure, which extends generally north-south for 15 kilometers, exhibits horizontal tensile failure and as much as 0.6 meter of normal dip-slip movement at the land surface. The west side of the fissure is down thrown. The fissure was observed as early as 1927 and is the longest earth fissure in Arizona. Vertical and horizontal displacements were monitored along a line normal to the fissure. The survey line extends from a bedrock outcrop in the Picacho Mountains on the east, past an observation well near the fissure, to a point 1,422 meters to the west. From May 1980 to May 1984, the downthrown west side of the fissure subsided 167+-1.8 millimeters and moved 18+-1.5 millimeters westward into the basin. Concurrently, the relatively upthrown east side subsided 148+-1.8 millimeters and moved 14+-1.5 millimeters westward. Dislocation modeling of deformation along the survey line near the fissure indicates that dip-slip movement has occurred along a vertical fault surface that extends from the land surface to a depth of about 300 meters. Slip was 9 millimeters from May to December 1980 and also 9 millimeters from March to November 1981. Continuous measurements were made of horizontal movement across the fissure using a buried invar-wire horizontal extensometer, while water-level fluctuations were continuously monitored in four piezometers nested in two observation wells. The range of horizontal movement was 4.620 millimeters, and the range of water-level fluctuation in the nearest piezometer in the deep alluvium was 9.05 meters. The maximum annual opening of the fissure during the study period was 3.740 millimeters from March to October

  13. Recrystallized Granite Surface Fissures of Wasatch Range Produced Not Later Than 1/4Billion Years Ago

    NASA Astrophysics Data System (ADS)

    McDonald, Keith

    2000-11-01

    Our studies of numerous recrystallized fissures in 4 granite plutons of Wasatch Range, i.e., Mount T-W-M, (K.L. McDonald, Bul. A.P.S., 32 (4), 1124),(37 (5), 1256-7),(38 (1), 740) Bonanza Pk.-Midway,(35 (9), 2132) Little Cottonwood and Ferguson Canyon plutons, all of which formed magma chambers reaching Earth-atm. interface, estab that they resulted from high thermal gradients and not passages of earthquake waves.(33 (9), 1982-2) Magma chambers formed, solidified during Permo- Carboniferous Ice Age (roughly 1/3...1/4 billion yr ago), a time interval preceding extrusion, pf Rocky Mts., 10^8 yr ago, and while fluid, some belched lava flows(36 (9), 2466) extending over its reservoir walls to run hundreds of m. We have shown how the magma melts, dilutes and replaces overlying metamorphic rock(38 (1), 740) to reach Earth's surface, so that a pluton containing large amounts of dross (Fe ores, etc.) had a short fluid lifetime. We also described how offshoots from a long-running main fissure form acute angles with that fissure.(33 (3), 485) Recryst. fissures, reaching depths of perhaps 100 m, had initial fractures near time of solidification of top portion of magma chamber, while still hot (<< 1600 ^oF), a time when max. stresses occur near granite surface due to high thermal gradients, owing to snow coverage, rain water, stream flow over granite surface, partial coverage by ocean, etc., during P-C ice age -- when region of Wasatch Range existed at sea level, S.L. Valley being covered entrely by ocean water and region of Wasatch Boul. rising gently above Pac. Ocean to elev. of possibly 500-1000 ft, say, at a dist. of 10-15 mi to e, as implied by Chinese Wall of limestone on Grandeur Pk, another in Neff's Canyon running e from n ridge of her 9200 ft saddle-summit, as well as a dozen other ancient calcified stream beds emptying into ocean to w., in S.L. Valley. This existed prior to regional uplift (of similar topog.) of over 4000 ft. Details of how earthquake waves form an

  14. Origins of Feeding Arteries of Hepatocellular Carcinoma Located Near the Umbilical Fissure of the Left Hepatic Lobe: Angiographic Evaluation

    SciTech Connect

    Miyayama, Shiro Yamashiro, Masashi; Shibata, Yoshihiro; Hashimoto, Masahiro; Yoshida, Miki; Tsuji, Kazunobu; Toshima, Fumihito; Matsui, Osamu

    2012-12-15

    Purpose: To analyze the origins of the feeding arteries of hepatocellular carcinomas (HCCs) near the umbilical fissure of the left hepatic lobe. Methods: Twenty-eight HCCs with a mean {+-} SD tumor diameter of 3.4 {+-} 1.0 cm (range 1-4.4 cm) in contact with the right or left side of the umbilical fissure were treated by superselective transcatheter arterial chemoembolization (TACE). The origins of the tumor-feeding arteries were analyzed with arteriograms and computed tomography or cone-beam computed tomography images obtained during and 1 week after TACE.ResultsTwenty-one HCC lesions were located in segment 3 and seven were located in segment 4. Of 21 tumors in segment 3, 13 (61.9%) were supplied by the lateral inferior subsegmental artery (A3), three (14.3%) by the medial subsegmental artery (A4), three (14.3%) by both A4 and A3, one (4.8%) by a branch arising from the left lateral hepatic artery, and one (4.8%) by a branch of the right gastric artery. In particular, all tumor-feeding branches arising from A4 were the first branch of A4. Of seven tumors in segment 4, four (57.1%) were supplied by A4 and three (42.9%) by A3. In particular, all tumor-feeding branches arising from A3 were the first branch of A3. Conclusion: This study demonstrates crossover blood supply to HCC lesions located near the umbilical fissure, in addition to direct feeding from a separate branch. In particular, the first branch of the opposite subsegmental artery may feed tumors when crossover blood supply is present.

  15. CHEMICAL TRANSPORT IN A FISSURED BOCK: VERIFICATION OF A NUMERICAL MODEL

    SciTech Connect

    Rasmuson, A.; Narasimhan, T.N.; Neretnieks, I.

    1982-04-01

    Numerical models for simulating chemical transport in fissured rocks constitute powerful tools for evaluating the acceptability of geological nuclear waste repositories. Due to the very long-term, high toxicity of some nuclear waste products, the models are required to predict, in certain cases, the spatial and temporal distribution of chemical concentration less than 0.001% of the concentration released from the repository. Whether numerical models can provide such accuracies is a major question addressed in the present work. To this end, we have verified a numerical model, TRUMP, which solves the advective diffusion equation in general three dimensions with or without decay and source terms. The method is based on an integrated finite-difference approach. The model was verified against known analytic solution of the one-dimensional advection-diffusion problem as well as the problem of advection-diffusion in a system of parallel fractures separated by spherical particles. The studies show that as long as the magnitude of advectance is equal to or less than that of conductance for the closed surface bounding any volume element in the region (that is, numerical Peclet number <2), the numerical method can indeed match the analytic solution within errors of ±10{sup -3} % or less. The realistic input parameters used in the sample calculations suggest that such a range of Peclet numbers is indeed likely to characterize deep groundwater systems in granitic and ancient argillaceous systems. Thus TRUMP in its present form does provide a viable tool for use in nuclear waste evaluation studies. A sensitivity analysis based on the analytic solution suggests that the errors in prediction introduced due to uncertainties in input parameters is likely to be larger than the computational inaccuracies introduced by the numerical model. Currently, a disadvantage in the TRUMP model is that the iterative method of solving the set of simultaneous equations is rather slow when time

  16. Chemical Transport in a Fissured Rock: Verification of a Numerical Model

    NASA Astrophysics Data System (ADS)

    Rasmuson, A.; Narasimhan, T. N.; Neretnieks, I.

    1982-10-01

    Numerical models for simulating chemical transport in fissured rocks constitute powerful tools for evaluating the acceptability of geological nuclear waste repositories. Due to the very long-term, high toxicity of some nuclear waste products, the models are required to predict, in certain cases, the spatial and temporal distribution of chemical concentration less than 0.001% of the concentration released from the repository. Whether numerical models can provide such accuracies is a major question addressed in the present work. To this end we have verified a numerical model, TRUMP, which solves the advective diffusion equation in general three dimensions, with or without decay and source terms. The method is based on an integrated finite difference approach. The model was verified against known analytic solution of the one-dimensional advection-diffusion problem, as well as the problem of advection-diffusion in a system of parallel fractures separated by spherical particles. The studies show that as long as the magnitude of advectance is equal to or less than that of conductance for the closed surface bounding any volume element in the region (that is, numerical Peclet number <2), the numerical method can indeed match the analytic solution within errors of ±10-3% or less. The realistic input parameters used in the sample calculations suggest that such a range of Peclet numbers is indeed likely to characterize deep groundwater systems in granitic and ancient argillaceous systems. Thus TRUMP in its present form does provide a viable tool for use in nuclear waste evaluation studies. A sensitivity analysis based on the analytic solution suggests that the errors in prediction introduced due to uncertainties in input parameters are likely to be larger than the computational inaccuracies introduced by the numerical model. Currently, a disadvantage in the TRUMP model is that the iterative method of solving the set of simultaneous equations is rather slow when time

  17. Geophysical Exploration of Faults, Fissures, and Fractures at Four Sites in Mexicali, Baja California, Mexico

    NASA Astrophysics Data System (ADS)

    Lázaro-Mancilla, O.; Gonzalez-Fernandez, A.; Contreras-Corvera, A.; Stock, J. M.; Moreno-Ayala, D.; Ramirez-Hernandez, J.; Carreon-Diazconti, C.; Lopez, D. A. L.; Lopez, J. R.

    2014-12-01

    We conducted field geophysical measurements in areas in the City of Mexicali that are associated with geological faults, fissures, and fractures. The study sites are: 1) Instituto Tecnologico de Mexicali 2) The buried trace of the Michoacan de Ocampo fault in the urban zone 3) Rio Nuevo 4) A site reported by Frez (2013) with ground rupture SW of Cerro Prieto At Site 1, seismic reflection profiling used a cable with 24 geophones at 1 m spacing. The source was a 3.6 kg sledge hammer, with 3 impacts per shot point. 347 shot points at 2 m spacing provided 6 fold coverage along a straight line with minimal elevation changes. Sample rate was 2000/s, and record length 1 s; reflections were seen down to 0.3 s TWTT. Processing included: frequency filter, fk filter, predictive deconvolution, geometry, velocity analysis, NMO and stacking. Lateral changes in the seismic section are due to surface modification and/or the presence of faults.At site 2, we measured 222Radon in 36 locations along 17 profiles across the fault, using inherent alpha spectrometry with a Durridge RAD7 detector. Each site was measured at a depth of 60 cm, with 31 five-minute readings in a 3 hour period, interspersed with 10 minute of background purge and 3 five-minute background measurements. In a profile parallel to the fault, 78% of the readings were > 100 pCi/L, confirming the presence of the fault along the swath surveyed. At Site 3 we compiled observations of post-earthquake cracks, conducted reconnaissance, and measured some profiles using 100 MHz GPR. These observations showed that the cracks are associated with ground failure due to earthquake shaking. At Site 4 our new 222Radon gas measurements complemented a pre-existing profile that had high 222Radon values lacking a structural explanation. Related to this we found that this region has two NW-SE trending features: a magnetic anomaly low of 360 nT (Evans, Summer and Castillo, 1972) and a graben reported by the Mexican Geological Survey in 2003

  18. Deformation precursory to the March 2011 Kamoamoa fissure eruption, Kilauea Volcano, Hawai'i

    NASA Astrophysics Data System (ADS)

    Lundgren, P.; Poland, M. P.; Miklius, A.

    2012-12-01

    We examine surface deformation of Kilauea Volcano prior to the March 5, 2011, Kamoamoa fissure eruption along the volcano's east rift zone (ERZ). The Kamoamoa eruption followed several months of magma accumulation beneath Kilauea's summit. In addition to inflation of a shallow (1.5-2 km depth) source near Halema'uma'u Crater, precursory deformation at Kilauea 's summit is attributable to sources distinct in space and time from previously identified zones of magma storage and faulting. Differential interferometric synthetic aperture radar (InSAR) data from the COSMO-SkyMed (CSK) and TerraSAR-X (TSX) satellites, combined with GPS data, show evidence for two additional sources active during the inflation prior to the Kamoamoa eruption: 1) progressive inflation of a triangular-shaped area extending from the southern edge of Kilauea Caldera and west of the ERZ, and 2) a nearly vertical extensional feature beneath the western edge of Kilauea Caldera. While the shallow Hale'mau'mau source appears to have gained in volume during the entire period, the triangular source in the south caldera became active in the final month prior to the Kamoamoa eruption. Inflation of this source reversed to deflation during the eruption. The extensional source beneath the western caldera, evident in the last quarter of 2010, also appears to have reversed its sense of motion during the eruption. To model the sources, we use a Markov chain Monte Carlo optimization. Compared to previously observed deformation due to deflation-inflation events within the caldera, the deformation preceding the Kamoamoa eruption extends farther ESE. In these preliminary models, we use a spheroidal source with a sub-horizontal long axis striking roughly E-W. The source south of the caldera is modeled as a rectangular tensile dislocation that is sub-horizontal at roughly 2 km depth, similar to the spheroidal source. The western caldera sub-vertical tensile dislocation extends from within a few hundred meters

  19. Subsurface flow behavior in thick colluvium and fissured bedrock in Kumano-daira, Central Japan

    NASA Astrophysics Data System (ADS)

    Hattori, S.; Onda, Y.; Tanaka, T.; Shimamura, M.; Togari-Ohta, A.; Uchida, T.; Tsujimura, M.

    2005-12-01

    Kumanodaira catchment was hypothesized; because of the thick colluvium, long time is required to infiltrate to the soil/bedrock interface and mainly composed of larger storm water. The soil water immediately above the soil/bedrock interface would infiltrate to the large fissures of the bedrock, preserving the isotopic signal and flowing quickly to the stream.

  20. Increased anal basal pressure in chronic anal fissures may be caused by overreaction of the anal-external sphincter continence reflex.

    PubMed

    van Meegdenburg, Maxime M; Trzpis, Monika; Heineman, Erik; Broens, Paul M A

    2016-09-01

    Chronic anal fissure is a painful disorder caused by linear ulcers in the distal anal mucosa. Even though it counts as one of the most common benign anorectal disorders, its precise etiology and pathophysiology remains unclear. Current thinking is that anal fissures are caused by anal trauma and pain, which leads to internal anal sphincter hypertonia. Increased anal basal pressure leads to diminished anodermal blood flow and local ischemia, which delays healing and leads to chronic anal fissure. The current treatment of choice for chronic anal fissure is either lateral internal sphincterotomy or botulinum toxin injections. In contrast to current thinking, we hypothesize that the external, rather than the internal, anal sphincter is responsible for increased anal basal pressure in patients suffering from chronic anal fissure. We think that damage to the anal mucosa leads to hypersensitivity of the contact receptors of the anal-external sphincter continence reflex, resulting in overreaction of the reflex. Overreaction causes spasm of the external anal sphincter. This in turn leads to increased anal basal pressure, diminished anodermal blood flow, and ischemia. Ischemia, finally, prevents the anal fissure from healing. Our hypothesis is supported by two findings. The first concerned a chronic anal fissure patient with increased anal basal pressure (170mmHg) who had undergone lateral sphincterotomy. Directly after the operation, while the submucosal anesthetic was still active, basal anal pressure decreased to 80mmHg. Seven hours after the operation, when the anesthetic had completely worn off, basal anal pressure increased again to 125mmHg, even though the internal anal sphincter could no longer be responsible for the increase. Second, in contrast to previous studies, recent studies demonstrated that botulinum toxin influences external anal sphincter activity and, because it is a striated muscle relaxant, it seems reasonable to presume that it affects the striated

  1. Assessment of the inhibitory effects of fissure sealants on the demineralization of primary teeth using an automatic pH-cycling system.

    PubMed

    Ushimura, Shuya; Nakamura, Koichi; Matsuda, Yasuhiro; Minamikawa, Hajime; Abe, Shigeaki; Yawaka, Yasutaka

    2016-01-01

    In this study, we examined the effects of fissure sealants on inhibition of demineralization of primary teeth using an automatic pHcycling system. Three fissure sealants were used: Teethmate F-1 2.0 (TM), BeautiSealant (BS), and Fuji III LC (IIILC). Using an automatic pH-cycling system, the specimens (n=12) were repeatedly demineralized and remineralized. Specimens were subjected to transverse microradiography (TMR), and changes in integrated mineral loss (IML) and lesion depth (Ld), indicated as ΔIML and ΔLd, respectively, were calculated. In addition, fluoride levels in the enamel were assessed using microparticle-induced gammaray emission/particle-induced X-ray emission (n=3). IIILC showed the lowest values for ΔIML and ΔLd, followed by BS and then TM. The highest amount of fluorine in the enamel was observed for IIILC, followed by TM and BS. All fissure sealants inhibited demineralization in primary teeth. PMID:27041023

  2. Native gold from volcanic gases at Tolbachik 1975-76 and 2012-13 Fissure Eruptions, Kamchatka

    NASA Astrophysics Data System (ADS)

    Chaplygin, Ilya; Yudovskaya, Marina; Vergasova, Lidiya; Mokhov, Andrey

    2015-12-01

    Aggregates and euhedral crystals of native gold were found in sublimates formed during New Tolbachik Fissure Eruption in 2012-2013 (NTFE). Gold-bearing sublimate samples were taken from a red-hot (690 °C) degassing fracture in the roof of an active lava tunnel 1.5 km from active Naboko cinder cone in May 2013. The gas condensate collected at 690 °C in this site contains 16 ppb Au, 190 ppb Ag and 1180 ppm Cu compared to 3 ppb Au, 39 ppb Ag and 9.7 ppm Cu in the condensate of pristine magmatic gas sampled at 1030 °C. The 690 °C volcanic gas is most likely a mix of magmatic gas and local snow buried under the lava flows as indicated by oxygen and hydrogen isotope compositions of the condensate. The lower-temperature gas enrichment in gold, copper and chlorine is resulted from evaporation of the 690 °C condensate during forced gas pumping at sampling. Native gold was also found in fumarolic encrustations collected from caverns in basalt lava flows with temperature up to 600 °C in June 2014, in a year after eruption finished. The native gold precipitation in newly formed Cu-rich sublimates together with the well known gold occurrences in cinder cones of 1975-1976 Large Tolbachik Fissure Eruption manifest a transport capability of oxidized volcanic gas.

  3. Microtensile bond strength of a resin-based fissure sealant to Er,Cr:YSGG laser-etched primary enamel.

    PubMed

    Sungurtekin-Ekci, Elif; Oztas, Nurhan

    2016-05-01

    The aim of this study was to evaluate the effect of Er,Cr:YSGG laser pre-treatment alone, or associated with acid-etching, on the microtensile bond strength of a resin-based fissure sealant to primary enamel. Twenty-five human primary molars were randomly divided into five groups including (1) 35 % acid etching, (2) 2.5-W laser etching, (3) 3.5-W laser etching, (4) 2.5-W laser etching + acid etching, and (5) 3.5-W laser etching + acid etching. Er,Cr:YSGG laser was used at a wavelength of 2.780 nm and pulse duration of 140-200 μs with a repetition rate of 20 Hz. Following surface pre-treatment, the fissure sealant (ClinPro™, 3M Dental Products) was applied. Each tooth was sectioned and subjected to microtensile testing. Kruskal-Wallis test was used for statistical analysis. The level of significance was set at p < 0.05. The microtensile bond strength values of group 1 were significantly higher than those of group 2, while no statistically significant difference was detected between groups 1, 3, 4, and 5. It was concluded that 3.5-W laser etching produced results comparable to conventional acid etching technique, whereas 2.5-W laser etching was not able to yield adequate bonding performance. PMID:25847685

  4. 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.

  5. Diagnosis of pit and fissure caries using frequency-domain infrared photothermal radiometry and modulated laser luminescence.

    PubMed

    Jeon, R J; Han, C; Mandelis, A; Sanchez, V; Abrams, S H

    2004-01-01

    Non-intrusive, non-contacting frequency-domain photothermal radiometry (FD-PTR or PTR) and frequency-domain luminescence (FD-LUM or LUM) have been used with 659- and 830-nm laser sources to assess the pits and fissures on the occlusal surfaces of human teeth. Fifty-two human teeth were examined with simultaneous measurements of PTR and LUM and were compared to conventional diagnostic methods including continuous (dc) luminescence (DIAGNOdent), visual inspection and radiographs. To compare each method to the others, sensitivities and specificities were calculated by using histological observations as the gold standard. With the combined criteria of four PTR and LUM signals (two amplitudes and two phases), it was found that the sensitivity of this method was much higher than any of the other methods used in this study, whereas the specificity was comparable to that of dc luminescence diagnostics. Therefore, PTR and LUM, as a combined technique, has the potential to be a reliable tool to diagnose early pit and fissure caries and could provide detailed information about deep lesions. Using the longer wavelength (830-nm) laser source, it has been shown that detection of deeper subsurface lesions than the 659-nm probe provides is possible. PMID:15528904

  6. Recrystallized Granite Surface Fissures Of Wasatch Range, Produced Not Later Than 1/4 Billion Years Ago.

    NASA Astrophysics Data System (ADS)

    McDonald, K. L.

    2002-04-01

    Our studies of numerous recrystallized fissures in 4 granite plutons of Wasatch Range, i.e., Mount T-W-M^1,6,7 Bonanza Pk.-Midway,^2 Little Cottonwood and Ferguson Canyon plutons, all of which formed magma chambers reaching Earth-atm. interface, estab. that they resulted from high thermal gradients and not passages of earthquake waves.^4 Magma chambers formed, solidified during Permo-Carboniferous Ice Age (roughly 1/3...1/4 billion yr ago), a time interval preceding extrusion of Rocky Mts., 10^8 yr ago, and while fluid, some belched lava flows^5 extending over its reservoir walls to run hundreds of m. We have shown how the magma melts, dilutes and replaces overlying metamorphic rock^7 to reach Earth's surface, so that a pluton containing large amounts of dross (Fe-ores, etc.) had a short fluid lifetime. We also described how offshoots from a long-running main fissure form acute angles with that fissure^3. Recryst. fissures, reaching depths of perhaps 100 m, had initial fractures near time of solidification of top portion of magma chamber, while still hot (<= 1600^oF), a time when max. stresses occur near granite surface due to high thermal gradients, owing to snow coverage, rain water, stream flow over granite surface, partial coverage by ocean, etc., during P-C ice age - when region of Wasatch Range existed at sea level, S. L. Valley being covered entirely by ocean water and region east of Wasatch Boul. rising gently above Pac. Ocean to elev. of possibly 500-1000 ft, say, at a distance of 10-15 mi to e, as implied by Chinese wall of limestone on Grandeur Pk, another in Neff's Canyon running e from n ridge of her 9200 ft saddle-summit, as well as a dozen other ancient calcified stream beds emptying into ocean to w, in S.L. Valley. This existed prior to regional uplift (of similar topog.) of over 4000 ft. Details of how earthquake waves form an epicenter from which propagate 2 stress fields in diam. opp. directions to open up, by a few m, surface granite to form a

  7. Comparison of Clinical Success of Applying a Kind of Fissure Sealant on the Lower Permanent Molar Teeth in Dry and Wet Conditions

    PubMed Central

    Eskandarian, Tahereh; Baghi, Saeid; Alipoor, Abbas

    2015-01-01

    Statement of the Problem Fissure sealant therapy is among the most effective methods of preventing dental caries. However, it is lengthy and isolation of the teeth is difficult in this procedure especially in young children. Using new hydrophilic fissure sealant may reduce such problems. Purpose This study aimed to evaluate the clinical success of a hydrophilic fissure sealant on the lower permanent molar teeth in dry and wet conditions. Materials and Method This clinical trial assessed 31 patients (mean age 8.13±1.77 years) who needed fissure sealant therapy on their first or second mandibular permanent molar. Having performed dental prophylaxis, the teeth were etched and rinsed. Then one of the two was randomly selected and sealed with smartseal & loc in isolated and dry conditions; while, the other was wetted on the etched enamel by using a saliva-contaminated micro brush, and was then sealed with the same fissure as the first tooth. Six and 12 months later, two independent observers examined the clinical success of sealant through checking the marginal integrity, marginal discoloration, and anatomical form. Data were analyzed by using SPSS software, version 16. The bivariate Chi-square and Exact Fisher tests were used to compare the clinical success of the two treatment methods. Results There was a high interpersonal reliability between the two examiners (K= 0.713). After 12 months, 90.3% clinical success was observed in dry conditions and 83.9% in wet conditions for smartseal & loc; however, the difference was not statistically significant (p= 0.0707). Conclusion According to the results of this study, it seems that using new hydrophilic fissure sealant can reduce technical sensitivities and consequently decreases the apprehensions on saliva contamination of etched enamel during treatment procedures. PMID:26331144

  8. The ‘Excess’ Emission from the Warm Surface Adjacent to Active Fissures on Enceladus from Combined VIMS and CIRS Spectra

    NASA Astrophysics Data System (ADS)

    Goguen, Jay D.; Buratti, Bonnie J.; Howell, Robert R.

    2015-11-01

    The exciting discovery of thermal emission from the tiger stripe fissures at the S. pole of Enceladus is a major highlight of the Cassini mission. Both VIMS (Visible and Infrared Mapping Spectrometer) and CIRS (Composite InfraRed Spectrometer) detect the thermal ‘blackbody’ spectrum emitted from the warm fissure areas. The VIMS instrument is uniquely suited to measuring the hottest active locations because VIMS covers the 3 to 5 micron wavelength range where the rising edge of the Planck function for these T~200 K areas dominates the emission spectrum. At longer wavelengths, the spectrum is more complicated because contributions from small hot areas and larger cooler areas combine to form the broad emission spectrum that is detected by the CIRS instrument at wavelengths >6.7 microns. It is the combination of VIMS and CIRS spectra that paint a more complete portrait of the fissure heat transfer processes. Using spectra that span both the VIMS and CIRS wavelengths places a stronger constraint on the T distribution near the fissures than consideration of the spectra from either instrument alone.We show that when the best (= highest spatial resolution, 800 m/pixel and smaller) VIMS and CIRS spectra of the fissure thermal emission are considered together, there is a large (up to 400%) component of ‘excess’ emission spanning 7 to 17 microns that requires explanation. New analysis of ~2 km spatial resolution VIMS spectra of the Damascus hot spot on 8/13/2010 are similar to the highest resolution 4/14/2012 VIMS Baghdad spectra, confirming that differences in location or time between the best VIMS and CIRS spectra do not explain away the excess. The obvious interpretation is that there are processes that transfer heat from the fissure eruption to the surface within 400 m of the fissure center in addition to heat conduction through the fissure walls. Candidate heat transfer processes include fallback of large warm low velocity ice particles from the edges of the

  9. Mechanisms, Monitoring and Modeling Earth Fissure generation and Fault activation due to subsurface Fluid exploitation (M3EF3): A UNESCO-IGCP project in partnership with the UNESCO-IHP Working Group on Land Subsidence

    NASA Astrophysics Data System (ADS)

    Teatini, P.; Carreon-Freyre, D.; Galloway, D. L.; Ye, S.

    2015-12-01

    Land subsidence due to groundwater extraction was recently mentioned as one of the most urgent threats to sustainable development in the latest UNESCO IHP-VIII (2014-2020) strategic plan. Although advances have been made in understanding, monitoring, and predicting subsidence, the influence of differential vertical compaction, horizontal displacements, and hydrostratigraphic and structural features in groundwater systems on localized near-surface ground ruptures is still poorly understood. The nature of ground failure may range from fissuring, i.e., formation of an open crack, to faulting, i.e., differential offset of the opposite sides of the failure plane. Ground ruptures associated with differential subsidence have been reported from many alluvial basins in semiarid and arid regions, e.g. China, India, Iran, Mexico, Saudi Arabia, Spain, and the United States. These ground ruptures strongly impact urban, industrial, and agricultural infrastructures, and affect socio-economic and cultural development. Leveraging previous collaborations, this year the UNESCO Working Group on Land Subsidence began the scientific cooperative project M3EF3 in collaboration with the UNESCO International Geosciences Programme (IGCP n.641; www.igcp641.org) to improve understanding of the processes involved in ground rupturing associated with the exploitation of subsurface fluids, and to facilitate the transfer of knowledge regarding sustainable groundwater management practices in vulnerable aquifer systems. The project is developing effective tools to help manage geologic risks associated with these types of hazards, and formulating recommendations pertaining to the sustainable use of subsurface fluid resources for urban and agricultural development in susceptible areas. The partnership between the UNESCO IHP and IGCP is ensuring that multiple scientific competencies required to optimally investigate earth fissuring and faulting caused by groundwater withdrawals are being employed.

  10. 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

  11. 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

  12. Impact of effusive eruptions from the Eguas-Carvão fissure system, São Miguel Island, Azores Archipelago (Portugal)

    NASA Astrophysics Data System (ADS)

    Pedrazzi, Dario; Cappello, Annalisa; Zanon, Vittorio; Del Negro, Ciro

    2015-01-01

    The hazard and risk posed by future effusive eruptions from the Éguas-Carvão fissure system in São Miguel Island (Azores Archipelago) are assessed. This fissure system, located ~ 13 km from the town of Ponta Delgada and its international airport, was the only site in the whole island to be characterized by recurrent basaltic eruptions over the past 5000 yr. Here we report on the stratigraphic record of these Holocene eruptions, with special mention to both areas and volumes of deposits, and eruptive styles and recurrence. These basic data then are used to constrain numerical simulations of lava flow paths using the MAGFLOW model, after which hazard zones of possible future events are proposed. The lava flow risk is evaluated by combining the hazard with the exposed value, referred to the population, infrastructures and land use. These results are shown in two distinct maps, where the areas most prone to lava flow inundation and the extent of damages in case of a future effusive eruption are identified. We find that lava flows issuing from the Éguas-Carvão fissure system may be a threat to the villages of Feteiras, Capelas and Santo Antonio. Although this study was conducted on the Éguas-Carvão fissure system, the approach used can be applied to the whole São Miguel Island.

  13. Dike Propagation Mechanisms from Seismicity Accompanying the 2014 Bárðarbunga-Holuhraun Fissure Eruption, Iceland

    NASA Astrophysics Data System (ADS)

    Woods, J.; Ágústsdóttir, T.; Greenfield, T. S.; Green, R. G.; White, R. S.; Brandsdottir, B.

    2015-12-01

    We present data from our dense seismic network which captured in unprecedented detail the micro-seismicity associated with the 2014 dike intrusion from the subglacial Bárðarbunga volcano in central Iceland. Over 30,000 automatically located earthquakes delineate a complex 46 km dike propagation during the days preceding the onset of effusive magmatism at the Holuhraun lava field on 29 August 2014. Approximately 1.5 km3 of lava was erupted, making this the largest eruption in Iceland for over 200 years.Micro-seismicity tracks the lateral migration of the dike, with a concentration of earthquakes in the advancing tip where stresses are greatest, and trailing zones of lesser or no seismicity behind. Onset of an initial 4 hour fissure eruption was accompanied simultaneously by a backward retreat in seismic activity, followed by a gradual re-advance prior to the onset of a second, sustained fissure eruption in the same location on 31 August. Rock fracture mechanisms are determined from fault plane solutions of these seismic events. At the tip of the advancing dike, left-lateral strike-slip faulting parallel to the propagation is dominant, utilising pre-existing lineations and releasing stress accumulated in the brittle layer from rift zone extension. Behind the dike tip, both right-lateral and left-lateral strike-slip earthquakes are found, marking failure of solidifying magma plugs within the dike conduit. Contrary to many models of dike propagation, both normal faulting and failure at high angles to the dike are rare. Furthermore, a distinct lack of seismicity is observed in the 3-4 km region beneath the surface rupture. This suggests that opening is occuring aseismically, with earthquakes focused at the base of the dike near the brittle-ductile boundary.

  14. Knowledge, value, opinion and practice about usage of pit and fissure sealant among dental professionals in Chennai, Tamil Nadu, India

    PubMed Central

    Nagappan, N.; Dhamodhar, M. Dinesh; Nithin, M. G.; Kumar, E. Senthil

    2015-01-01

    Aim: A study was aimed to assess the knowledge, value, opinion, and practice regarding the use of dental sealants among private dental practitioners in Chennai, Tamil Nadu, India. Materials and Methods: A self-administrated questionnaire were distributed to 192 private dental practitioners in Chennai, Tamil Nadu, India by using simple random sampling. A convenience sampling technique was employed. The questionnaire consisted of 28 items, which included information about knowledge, value, opinion, and practice regarding dental sealants. The questionnaire was obtained from the study by San Martin et al. 2013 and Kailash Asawa et al. 2014. Frequency distribution was tabulated. For frequency distribution strongly, strongly agree, and agree were combined as “agree” and strongly disagree and disagree were combined as “disagree.” There were no changes in “neutral.” Results: Among the 196 study subjects 56.2% were males and 43.8% were females with their clinical experience of 52.1% for <5 years, 35.4% for 5–10 years, and 13.5% for >15 years. The mean scores for knowledge, value, opinion, and practice were 41.8 ± 3.7, 18.7 ± 2.8, 18.1 ± 1.4, and 12.9 ± 2.3, respectively. Conclusion: The results suggest that dental practitioners had satisfactory knowledge about pit and fissure sealant and had neutral attitudes about sealants being effective. Dental practitioners adequately used the pit and fissure sealants but they did not follow the standardized procedures and specific guidelines. PMID:26942116

  15. Plateau versus fissure ridge travertines from Quaternary geothermal springs of Italy and Turkey: Interactions and feedbacks between fluid discharge, paleoclimate, and tectonics

    NASA Astrophysics Data System (ADS)

    De Filippis, Luigi; Faccenna, Claudio; Billi, Andrea; Anzalone, Erlisiana; Brilli, Mauro; Soligo, Michele; Tuccimei, Paola

    2013-08-01

    Morphologically-different deposits of thermal travertines are known worldwide, but what factors controlled their morphology, volume, and growth for tens of thousands of years is only partially understood. Two main morphotypes of Quaternary thermal travertines are reconsidered here to understand the reasons for their differential growth: the fissure ridge travertines of Denizli Basin, western Turkey, and the travertine plateau of Tivoli, central Italy. For comparable longevities and average vertical deposition rates, the main differences between the studied travertines are as follows: (1) volume of the travertine plateau is about one hundred times larger than each fissure ridge; (2) despite a larger volume, the travertine plateau does not produce relief, whereas the fissure ridges produce a characteristic prominent topography; (3) the travertine plateau grew primarily through lateral progradation, whereas the fissure ridges through vertical aggradation; (4) travertine deposition occurred in different environments: principally low-energy flat or shallow environments at Tivoli and high-energy inclined environments at Denizli; (5) the growth of the Tivoli plateau occurred in a subsiding basin, whereas the fissure ridges were not influenced by significant subsidence; (6) C- and O-isotope signatures from the two studied travertines are different; (7) despite similar annual precipitations, the present water discharge in the Tivoli area is about ten times greater than that of the Denizli Basin. U-series ages from the two deposits are correlated with paleoclimate oscillations at regional and global scales. Geological field evidence together with paleoclimate correlations suggest that, in both the study cases, the main body of travertine deposits (the bedded travertine) grew preferentially when the water table was high (warm and/or humid periods). Conversely, when the water table was depressed (cold and/or dry periods), the Tivoli travertine underwent partial erosion and the

  16. Comparative evaluation of the length of resin tags, viscosity and microleakage of pit and fissure sealants – an in vitro scanning electron microscope study

    PubMed Central

    Prabhakar, A.R.; Murthy, Sankriti A.; Sugandhan, S.

    2011-01-01

    Introduction: In this era of preventive dentistry, many techniques are available for prevention of caries, such as plaque control, use of systemic and local fluorides and pit and fissure sealants. The rationale of pit and fissure sealants is that, when they are applied into the caries prone fissures, they penetrate and seal them from the oral environment. This study aims to correlate the relationship between the viscosity of the sealant, resin tag length and microleakage. Materials and Methods: 30 third molars were selected for study. The teeth were randomly divided into 3 groups. Group E: Embrace wetbond, H: Helioseal, G: Guardian seal. Teeth were cleaned with pumice prophylaxis and pretreated with acid etching and bonding agent. The respective pit and fissure sealants were applied. Teeth were placed in 1% methylene blue dye and sectioned mesio-distally into two halves. These were used to assess the microleakage using stereomicroscope and resin tag length using SEM. Viscosity was assessed using Brooke's field viscometer. Results: Viscosity was lowest for Embrace wetbond and highest for Guardian seal. Microleakage scores were highest with Guardian seal and lowest with Embrace wetbond. Resin tag lengths were longer with Embrace wetbond as compared to other groups. There is a definite negative correlation between viscosity, resin tag length and microleakage. Lower the viscosity, the longer were the resin tags and the microleakage decreased. Embrace wetbond pit and fissure sealant had lowest viscosity, longest resin tag length and lowest microleakage scores. Conclusion: Embrace wetbond appears to be compatible with residual moisture and ideal for use in children, where isolation is a problem. PMID:22346161

  17. Comparing Long and Short Term Deformation in the Krafla Fissure System, NE Iceland, using LiDAR, InSAR and GPS

    NASA Astrophysics Data System (ADS)

    Bramham, E.; Wright, T. J.; Paton, D. A.; Sigmundsson, F.; Pagli, C.

    2012-12-01

    The Krafla volcanic system is situated on the divergent plate boundary separating Eurasia from North America, one of five fissure swarms (rift segments) in the Northern Volcanic Zone (NVZ) of Iceland. The Krafla segment is a 5-10 km wide and 100 km long region consisting of a central volcano and fissure swarm. Dyke intrusions and fissure eruptions characterise the activity in Krafla. A rifting episode in 1975-1984 activated an 80 km long segment of the Krafla fissure swarm. The eruptive history suggests that the Krafla fissure swarm may not have been active for the whole of the last 10 ka, and that other rift segments may accommodate extension during periods of quiescence. Bjornsson (1977) estimated that the Northern Volcanic Zone has a major rifting event every ~ 100 years, each affecting only one of the five swarms. To better understand the deformation in this region we have attempted to determine whether faulting has been proceeding at a steady rate during this time period by examining both the long term (10 ka) and short term (10s of years) rates of vertical motion. To study the short-term vertical deformation during the post-rifting period in the Krafla system we have combined a series of interferometric synthetic aperture radar (InSAR) images, acquired by ERS and Envisat, with GPS data. The GPS data constrain the horizontal deformation - we remove the contribution of horizontal motion from the InSAR data to isolate the current vertical surface deformation rates. For the long term deformation, we have acquired high resolution LiDAR surveys over the Krafla fissure swarm in August 2007 and September 2008. We have interpolated these data to create a 1,300 km2 high resolution (~0.5 m) Digital Elevation Model (DEM) of the area. Using the DEM and ages of known lavas, we have estimated the average rate of vertical deformation during the post-glacial period for an area north of the main Krafla caldera, covered by a 10 ka old lava shield. Vertical deformation

  18. Oscillation of a Shallow Hydrothermal Fissure Inferred from Long-Period Seismic Events at Taal Volcano, the Philippines

    NASA Astrophysics Data System (ADS)

    Maeda, Y.; Kumagai, H.; Lacson, R.; Figueroa, M. S.; Yamashina, T.

    2012-12-01

    examine H2O gas (vapor) for simplicity. We calculated far-field waveforms generated by an oscillation of a crack containing vapor, and applied the Sompi method to estimate Q and nondimensional frequency. The estimated Q of a fundamental longitudinal mode oscillation was similar to the observation. We obtained a reasonable crack size (188 m) from a comparison of the observed peak frequency (0.8 Hz) with the calculated nondimensional frequency of the mode. In the swarm period of the LP events, other anomalies such as large volcano deformation and significant increase of gas emission from the main crater were not observed. This feature and the crack model result above suggest an active and localized vapor supply from magma at depth to the LP source. Such a localized supply may be realized by a transportation of vapor through a fissure. If we assume that the estimated crack volume (10^2 m^3) corresponds to vapor supplied to the LP source for each event, the total vapor mass supplied throughout the swarm period is ~10^7 kg. If we assume that this amount of vapor was originated by degassing from the magma and transported to the LP source through the fissure, we can estimate a magma volume of ~10^6 m^3. We thus suggest that the LP events at Taal were triggered by degassing and transportation of vapor from a deep magma to a shallow depth through a fissure.

  19. Potential for aquifer compaction, land subsidence, and earth fissures in Avra Valley, Pima and Pinal counties, Arizona

    USGS Publications Warehouse

    Anderson, S.R.

    1987-01-01

    Avra Valley is a large north-trending alluvial basin about 15 mi west of Tucson in Pima and Pinal Counties, Arizona. The climate of Avra Valley is semiarid, and the average annual precipitation ranges from 8 to 12 in. Two major ephemeral streams, the Santa Cruz River and Brawley Wash, drain the area. These streams and their tributaries provide a source of recharge to an extensive alluvial aquifer that underlies the valley floor. The aquifer consists of interbedded gravel, sand, silt, and clay and contains a vast quantity of groundwater. The physiography, fertile soil, and mild climate of Avra Valley make it an ideal environment for agriculture and urban development. Although the aquifer is replenished by natural recharge and underflow, rates of recharge and underflow have not kept pace with the rate of pumping. Pumping has exceeded recharge for several decades, resulting in a lowering of groundwater levels throughout most of the valley. In places, water level declines have resulted in small amounts of aquifer compaction and land subsidence. Earth fissures, some of which may be the result of localized differential subsidence, also have been observed in the valley. Geohydrologic characteristics of Avra Valley that may contribute to potential aquifer compaction, land subsidence, and earth fissures are described. The quantitative evaluation of potential land subsidence in this report is presented as an interim land- and water-use planning tool pending acquisition and study of additional data. Because of data limitations, the evaluation is made on the assumption that future rates of compaction and subsidence in Avra Valley will be similar to those in the Eloy-Picacho area. The evaluation also assumes that water level declines in the aquifer will continue. Several factors that may reduce groundwater withdrawals, and thus the potential for compaction and subsidence in Avra Valley, were not evaluated. These factors include the enactment of the 1980 Arizona Ground

  20. Fissured Rocks and Water Reservoirs in Eastern Thessaly Mountain Range, Greece (Olympus, Ossa, Maurovouni and Pelion): The Role of Tectonic Deformation

    NASA Astrophysics Data System (ADS)

    Papanikolaou, I.; Migiros, G.; Stamatis, G.; Yoxas, G.

    2009-04-01

    The storage capacity of fractured hard rocks is lower than porous media and karst formations, though they can yield groundwater of sufficiently good quality for drinking purposes and may host important water resources, even if they are often of low permeability. In particular, for countries like Greece, where water needs for the local population and the tourist industry are excessive and waterfall limited, these reservoirs are of strategic importance. The mountain Range in Eastern Thessaly comprises an extensive nappe of metamorphic rocks, consisting of schists, gneisses, involving partly some ophiolithic rocks and marble intercalations. The thickness of the nappe exceeds 600 m in Ossa, whereas in the area of Pelion is estimated up to 3.000 m. This nappe rests on top of the Autochthonous Olympus- Ossa unit, which forms a massive Mesozoic carbonate sequence. Extensive fieldwork data supported by the analysis of the physical and chemical properties of a large number of springs and combined by the study of the geological structure both local and regional, resulted in important outcomes regarding the fissured rocks permeability, water flow and springs distribution. Schists are characterized by heterogeneity regarding their permeability features. They are divided into hard-rocks where quartz, epidote and amphiboles prevail, displaying higher permeability and soft-rocks where clay minerals prevail, exhibiting low permeability features, because the presence of clay blocks the fissures and prevent any infiltration process. The marbles are of high permeability, but are of limited extent. A few springs are located in marbles, but the vast majority of the springs are associated to the hard-rock schists, are scattered and characterized by high seasonal discharges. In the area of Ossa in particular, the most important reservoirs exist at the bordering zones of the metamorphic and the post-alpine formations due to the enrichment of the sedimentary post-alpine formations. In the

  1. Genome-wide association studies of pit-and-fissure- and smooth-surface caries in permanent dentition.

    PubMed

    Zeng, Z; Shaffer, J R; Wang, X; Feingold, E; Weeks, D E; Lee, M; Cuenco, K T; Wendell, S K; Weyant, R J; Crout, R; McNeil, D W; Marazita, M L

    2013-05-01

    While genetics clearly influences dental caries risk, few caries genes have been discovered and validated. Recent studies have suggested differential genetic factors for primary dentition caries and permanent dentition caries, as well as for pit-and-fissure- (PF) and smooth- (SM) surface caries. We performed separate GWAS for caries in permanent-dentition PF surfaces (1,017 participants, adjusted for age, sex, and the presence of Streptococcus mutans) and SM surfaces (1,004 participants, adjusted for age, education group, and the presence of Streptococcus mutans) in self-reported whites (ages 14 to 56 yrs). Caries scores were derived based on visual assessment of each surface of each tooth; more than 1.2 million SNPs were either successfully genotyped or imputed and were tested for association. Two homologous genes were suggestively associated: BCOR (Xp11.4) in PF-surface caries (p value = 1.8E-7), and BCORL1 (Xq26.1) in SM-surface caries (p value = 1.0E-5). BCOR mutations cause oculofaciocardiodental syndrome, a Mendelian disease involving multiple dental anomalies. Associations of other plausible cariogenesis genes were also observed for PF-surface caries (e.g., INHBA, p value = 6.5E-6) and for SM-surface caries (e.g., CXCR1 and CXCR2, p value = 1.9E-6). This study supports the notion that genes differentially affect cariogenesis across the surfaces of the permanent dentition, and nominates several novel genes for investigation. PMID:23470693

  2. 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.

  3. Comparative study of fluoride released and recharged from conventional pit and fissure sealants versus surface prereacted glass ionomer technology

    PubMed Central

    Salmerón-Valdés, Elias Nahum; Scougall-Vilchis, Rogelio J; Alanis-Tavira, Jorge; Morales-Luckie, Raúl Alberto

    2016-01-01

    Context: The fluoride release of sealants in vitro shows a marked decrease. Giomers are distinguishable from manufactured resin-based sealants and contain prereacted glass-ionomer particles (PRG). Aims: To compare the amounts of fluoride released from the main pit and fissure of a resin-based sealant with that from a Giomer and to assess the abilities of the sealant and the Giomer to recharge when exposed to regular use of fluoride rinse. Materials and Methods: The readings for the fluoride concentration were carried out for 60 days using a fluoride ion-specific electrode. After this period, the samples were recharged using a fluoride mouth rinse. The amount of fluoride released after this recharge was determined for 5 days. The data were analyzed using Student's t- and analysis of variance tests. Results: In general, all materials presented higher fluoride release in the first 24 h; G1 and G4 showed a higher fluoride release in this period. On the other hand, G3 and G1 presented the most constant fluoride release until the 8th day, wherein all the sealants considerably decreased in the amount of fluoride released. Conclusion: G1 and G3 released higher concentrations of fluoride, although no significant differences were found. Giomers recharged in the first 24 h after polymerization presented an improved and sustained fluoride release. PMID:26957792

  4. Partitioning of Holocene kinematics and interaction between the Theistareykir Fissure Swarm and the Husavik-Flatey Fault, North Iceland

    NASA Astrophysics Data System (ADS)

    Tibaldi, A.; Bonali, F. L.; Einarsson, P.; Hjartardóttir, Á. R.; Pasquarè Mariotto, F. A.

    2016-02-01

    Our research is aimed at contributing to the general understanding of how transform-rift junctions work, a topic that can be studied in exceptional detail in North Iceland, where the active transform Husavik-Flatey Fault (HFF) connects with the Gudfinnugja Fault (GF), the westernmost structure of the Theistareykir Fissure Swarm (TFS). We studied in the field: i) offsets along the easternmost HFF, ii) the geometry and kinematics of 649 faults and 1208 tension fractures in the TFS, iii) the interactions among all these structures. The HFF transtensional kinematics is compatible with the GF, which shows different offsets north and south of the junction between these two faults. We suggest the possible prolongation of the HFF beyond the junction, based on: i) the change in offsets and strikes of TFS normal faults, ii) the presence of en-échelon, NNW-SSE-striking normal faults and tension fractures with a slight right-lateral component, iii) the transition of some of the faults into tension fractures north of the prolongation of the HFF, and iv) the decrease in the cumulated offset of all the faults north of the HFF prolongation. We interpret these data as field evidence of the first stages of propagation of the HFF upward or across the TFS: This has clear implications for defining the potential rupture length of the HFF and, hence, for seismic hazard assessment.

  5. Effects of Aloe vera cream on chronic anal fissure pain, wound healing and hemorrhaging upon defection: a prospective double blind clinical trial.

    PubMed

    Rahmani, N; Khademloo, M; Vosoughi, K; Assadpour, S

    2014-01-01

    Aloe vera is a medicinal plant that promotes wound healing in burn injuries. A prospective clinical trial was conducted to evaluate the effects of a topical cream containing 0.5% Aloe vera juice powder in the treatment of chronic anal fissures. The aloe cream was applied by the patients to the wound site 3 times per day for 6 weeks following the instructions of a physician. Pain was assessed with a visual analog scale before treatment and at the end of each week of treatment. Wound healing and the amount and severity of bleeding were examined and evaluated before and at the end of each week of treatment. There were statistically significant differences in chronic anal fissure pain, hemorrhaging upon defection and wound healing before and at the end of the first week of treatment also in comparison with control group (p < 0.0001). In this study, a topical cream containing aloe vera juice was an effective treatment for chronic anal fissures. This is a promising result indicating that further comparative studies are justified. PMID:24763890

  6. Poro-elastic modeling of Syringomyelia - a systematic study of the effects of pia mater, central canal, median fissure, white and gray matter on pressure wave propagation and fluid movement within the cervical spinal cord.

    PubMed

    Støverud, Karen H; Alnæs, Martin; Langtangen, Hans Petter; Haughton, Victor; Mardal, Kent-André

    2016-01-01

    Syringomyelia, fluid-filled cavities within the spinal cord, occurs frequently in association with a Chiari I malformation and produces some of its most severe neurological symptoms. The exact mechanism causing syringomyelia remains unknown. Since syringomyelia occurs frequently in association with obstructed cerebrospinal fluid (CSF) flow, it has been hypothesized that syrinx formation is mechanically driven. In this study we model the spinal cord tissue either as a poro-elastic medium or as a solid linear elastic medium, and simulate the propagation of pressure waves through an anatomically plausible 3D geometry, with boundary conditions based on in vivo CSF pressure measurements. Then various anatomic and tissue properties are modified, resulting in a total of 11 variations of the model that are compared. The results show that an open segment of the central canal and a stiff pia (relative to the cord) both increase the radial pressure gradients and enhance interstitial fluid flow in the central canal. The anterior median fissure, anisotropic permeability of the white matter, and Poisson ratio play minor roles. PMID:26176823

  7. Deep subsurface mine stalactites trap endemic fissure fluid Archaea, Bacteria, and Nematoda possibly originating from ancient seas.

    PubMed

    Borgonie, Gaëtan; Linage-Alvarez, Borja; Ojo, Abidemi; Shivambu, Steven; Kuloyo, Olukayode; Cason, Errol D; Maphanga, Sihle; Vermeulen, Jan-G; Litthauer, Derek; Ralston, Colin D; Onstott, Tullis C; Sherwood-Lollar, Barbara; Van Heerden, Esta

    2015-01-01

    Stalactites (CaCO3 and salt) from water seeps are frequently encountered in ceilings of mine tunnels whenever they intersect water-bearing faults or fractures. To determine whether stalactites could be mineralized traps for indigenous fracture water microorganisms, we analyzed stalactites collected from three different mines ranging in depth from 1.3 to 3.1 km. During sampling in Beatrix gold mine (1.4 km beneath the surface), central South Africa, CaCO3 stalactites growing on the mine tunnel ceiling were collected and observed, in two cases, to contain a living obligate brackish water/marine nematode species, Monhystrella parvella. After sterilization of the outer surface, mineral layers were physically removed from the outside to the interior, and DNA extracted. Based upon 16S and 18S rRNA gene sequencing, Archaea, Bacteria, and Eukarya in different combinations were detected for each layer. Using CT scan and electron microscopy the inner structure of CaCO3 and salt stalactites were analyzed. CaCO3 stalactites show a complex pattern of lamellae carrying bacterially precipitated mineral structures. Nematoda were clearly identified between these layers confirming that bacteria and nematodes live inside the stalactites and not only in the central straw. Salt stalactites exhibit a more uniform internal structure. Surprisingly, several Bacteria showing highest sequence identities to marine species were identified. This, together with the observation that the nematode M. parvella recovered from Beatrix gold mine stalactite can only survive in a salty environment makes the origin of the deep subsurface colonization enigmatic. The possibility of a Permian origin of fracture fluids is discussed. Our results indicate stalactites are suitable for biodiversity recovery and act as natural traps for microorganisms in the fissure water long after the water that formed the stalactite stopped flowing. PMID:26441844

  8. Evolution of dike opening during the March 2011 Kamoamoa fissure eruption, Kīlauea Volcano, Hawai`i

    USGS Publications Warehouse

    Lundgren, Paul; Poland, Michael; Miklius, Asta; Orr, Tim R.; Yun, Sang-Ho; Fielding, Eric; Liu, Zhen; Tanaka, Akiko; Szeliga, Walter; Hensley, Scott; Owen, Susan

    2013-01-01

    The 5–9 March 2011 Kamoamoa fissure eruption along the east rift zone of Kīlauea Volcano, Hawai`i, followed months of pronounced inflation at Kīlauea summit. We examine dike opening during and after the eruption using a comprehensive interferometric synthetic aperture radar (InSAR) data set in combination with continuous GPS data. We solve for distributed dike displacements using a whole Kīlauea model with dilating rift zones and possibly a deep décollement. Modeled surface dike opening increased from nearly 1.5 m to over 2.8 m from the first day to the end of the eruption, in agreement with field observations of surface fracturing. Surface dike opening ceased following the eruption, but subsurface opening in the dike continued into May 2011. Dike volumes increased from 15, to 16, to 21 million cubic meters (MCM) after the first day, eruption end, and 2 months following, respectively. Dike shape is distinctive, with a main limb plunging from the surface to 2–3 km depth in the up-rift direction toward Kīlauea's summit, and a lesser projection extending in the down-rift direction toward Pu`u `Ō`ō at 2 km depth. Volume losses beneath Kīlauea summit (1.7 MCM) and Pu`u `Ō`ō (5.6 MCM) crater, relative to dike plus erupted volume (18.3 MCM), yield a dike to source volume ratio of 2.5 that is in the range expected for compressible magma without requiring additional sources. Inflation of Kīlauea's summit in the months before the March 2011 eruption suggests that the Kamoamoa eruption resulted from overpressure of the volcano's magmatic system.

  9. Deep subsurface mine stalactites trap endemic fissure fluid Archaea, Bacteria, and Nematoda possibly originating from ancient seas

    PubMed Central

    Borgonie, Gaëtan; Linage-Alvarez, Borja; Ojo, Abidemi; Shivambu, Steven; Kuloyo, Olukayode; Cason, Errol D.; Maphanga, Sihle; Vermeulen, Jan-G; Litthauer, Derek; Ralston, Colin D.; Onstott, Tullis C.; Sherwood-Lollar, Barbara; Van Heerden, Esta

    2015-01-01

    Stalactites (CaCO3 and salt) from water seeps are frequently encountered in ceilings of mine tunnels whenever they intersect water-bearing faults or fractures. To determine whether stalactites could be mineralized traps for indigenous fracture water microorganisms, we analyzed stalactites collected from three different mines ranging in depth from 1.3 to 3.1 km. During sampling in Beatrix gold mine (1.4 km beneath the surface), central South Africa, CaCO3 stalactites growing on the mine tunnel ceiling were collected and observed, in two cases, to contain a living obligate brackish water/marine nematode species, Monhystrella parvella. After sterilization of the outer surface, mineral layers were physically removed from the outside to the interior, and DNA extracted. Based upon 16S and 18S rRNA gene sequencing, Archaea, Bacteria, and Eukarya in different combinations were detected for each layer. Using CT scan and electron microscopy the inner structure of CaCO3 and salt stalactites were analyzed. CaCO3 stalactites show a complex pattern of lamellae carrying bacterially precipitated mineral structures. Nematoda were clearly identified between these layers confirming that bacteria and nematodes live inside the stalactites and not only in the central straw. Salt stalactites exhibit a more uniform internal structure. Surprisingly, several Bacteria showing highest sequence identities to marine species were identified. This, together with the observation that the nematode M. parvella recovered from Beatrix gold mine stalactite can only survive in a salty environment makes the origin of the deep subsurface colonization enigmatic. The possibility of a Permian origin of fracture fluids is discussed. Our results indicate stalactites are suitable for biodiversity recovery and act as natural traps for microorganisms in the fissure water long after the water that formed the stalactite stopped flowing. PMID:26441844

  10. Ground based measurements of the gas emission from the Holuhraun volcanic fissure eruption on Iceland 2014/2015

    NASA Astrophysics Data System (ADS)

    Galle, Bo; Arellano, Santiago; Conde, Vladimir; Pfeffer, Melissa; Barsotti, Sara; Stefansdottir, Gerður; Bergsson, Baldur; Bergsson, Bergur; Ingvarsson, Thorgils; Weber, Konradin

    2015-04-01

    The since 31 August 2014 ongoing volcanic eruption at Holuhraun on Iceland is by far the strongest source of sulfur dioxide in Europe over the last 230 years with sustained emission rates exceeding 100 000 ton/day. This gas emission severely affects local population and has become a concern also for air traffic. The eruption has in December continued at constant pace for 3.5 months. Three scenarios are envisaged for the future; (1) the eruption stops, (2) the fissure extends under the Vattnajökul glacier and (3) Bardarbunga volcano erupts. The two later scenarios will cause increased gas emission, severe ash emissions and extended flooding. Under the scope of the EU-project FUTUREVOLC, a project with 3.5 years duration, aiming at making Iceland a supersite for volcanological research as a European contribution to GEO, we are developing a version of the Scanning DOAS instrument that is adapted to high latitudes with low UV radiation and severe meteorological conditions. Since the first day of the eruption several of these novel instruments has been monitoring the SO2 emission from the eruption. Data from our instruments are still after 3.5 months the only sustained ground-based monitoring of this gas emission. A lot of work is however needed to sustain this operation at a very remote site and under severe field conditions. At the same time the very high concentrations in the gas plume, in combination with bad meteorological conditions require the development of novel methods to derive reliable flux estimates. In this presentation we will discuss the instrumental issues and present the latest version of the emission estimates made from our measurements.

  11. Caries-Preventive Effect of High-Viscosity Glass Ionomer and Resin-Based Fissure Sealants on Permanent Teeth: A Systematic Review of Clinical Trials

    PubMed Central

    Mickenautsch, Steffen; Yengopal, Veerasamy

    2016-01-01

    Background Glass-ionomers are traditionally regarded to be inferior to resin as fissure sealants in protecting teeth from dental caries, due to their comparatively lower retention rate. Unlike low-viscosity glass-ionomers, high-viscosity glass-ionomer cements (HVGIC) are placed as sealants by pressing the material into pits and fissures with a petroleum-jelly-coated index finger. Hence, HVGIC sealants are assumed to penetrate pits and fissures deeper, resulting in a higher material retention rate, which may increase its caries-preventive effect. Methods The aim of this review was to answer the question as to whether, in patients with fully erupted permanent molar teeth, HVGIC based fissure sealants are less effective to protect against dental carious lesions in occlusal pits and fissures than resin-based fissure sealants? A systematic literature search in eight databases was conducted. Heterogeneity of accepted trials and imprecision of the established evidence were assessed. Extracted sufficiently homogenous datasets were pooled by use of a random-effects meta-analysis. Internal trial validity was evaluated. The protocol of this systematic review was registered with the International Prospective Register of Systematic Reviews (PROSPERO / Nr.: CRD42015016007). Results Seven clinical trials were provisionally included for further review. Of these, one was excluded. Seven trial reports reporting on six trials were accepted. From these, 11 datasets were extracted and pooled in four meta-analyses. The results suggest no statistically significant differences after up to 48 months and borderline significant differences in favour of HVGIC sealants after 60 months (RR 0.29; 95% CI: 0.09–0.95; p = 0.04 / RD -0.07; 95% CI: -0.14, -0.01). The point estimates and upper confidence levels after 24, 36, 48 and 60 months of RR 1.36; RR 0.90; RR 0.62; RR 0.29 and 2.78; 1.67; 1.21; 0.95, respectively, further suggest a chronological trend in favour of HVGIC above resin

  12. Dental caries and first permanent molar pit and fissure morphology in 7- to 8-year-old children in Wuhan, China.

    PubMed

    Wang, Jin-Dong; Chen, Xi; Frencken, Jo; Du, Min-Quan; Chen, Zhi

    2012-09-01

    To obtain the caries experience and, plaque accumulation severity and pit and fissure morphology in first permanent molars in 7-8 children in Wuhan, as a reasonable prediction of caries risk and preventive attention in the future, a convenient sample of five primary schools in the vicinity of the Wuhan University School and Hospital of Stomatology was drawn. Two calibrated examiners orally examined all present grade 2 children in the classroom, using standard caries plaque and tooth morphology criteria. Dental caries was scored at enamel (D(2)) and dentine (D(3)) for tooth and surface level. Independent variables were age, gender and school. Data analysis used analysis of variance and t-test. The sample comprised 1 043 7- and 8-year-olds. The prevalence of dental caries in permanent dentition was 8.7% and in primary dentition, 68.7%. Mean Decayed, Missing, Filled Teeth/S (DMFT/S) scores were 0.11 and 0.14, respectively. Mean dmft/s scores were 2.8 and 5.0. The d-component constituted 75% of the d(3)mft index, while enamel carious lesions constituted 36% of the total number of carious lesions (d(2,3)-component). Prevalence of medium and deep pits and fissures was 84.6%. Prevalence of medium and severe plaque accumulation was 67.4%. Prevalence of dental caries in the deciduous and permanent dentitions of 7- to 8-year-old children was high. Deep pits and fissures in high caries risk children should be sealed. PMID:22699265

  13. Effectiveness of Ozone with or without the Additional Use of Remineralizing Solution on Non-Cavitated Fissure Carious Lesions in Permanent Molars

    PubMed Central

    Atabek, Didem; Oztas, Nurhan

    2011-01-01

    Objectives: The aim of this study was to evaluate the efficiency of ozone alone and with a re-mineralizing solution following application on initial pit and fissure caries lesions in permanent molars. Methods: Forty children (9–12 years) having non-cavitated fissure caries lesions on bilateral 40 first permanent mandibular molar teeth were participated in the study. Patients were randomly allocated to 2 experimental groups consisting of 20 subjects. In the first group, ozone was applied once for 40 seconds to the assigned test teeth of each pair. In the second group, ozone was applied once for 40 seconds to the assigned test teeth of each pair with the use of re-mineralizing solution. Progression or improvement of the caries was assessed at baseline, immediately after treatment and at 1-,2-,3-, and 6 month follow-up by comparing the DIAGNOdent values, Clinical Severity Indexes, Oral Hygiene Scores. The results were analyzed statistically by using the Wilcoxon-Test for dependent samples in each group. When comparing different test groups (control and experimental groups) the Friedman S test followed by the Mann-Whitney U test was used. Results: A statistically significant difference was found between all of the control and experimental test lesions in each group (P<.001). However, there was no statistically significant difference between the ozone treated groups and those using the additional re-mineralizing solution (P>.001). Conclusions: Ozone treatment either alone or combined with a re-mineralizing solution was found to be effective for remineralization of initial fissure caries lesions. PMID:22654551

  14. Comparative evaluation of Shear bond strength of different Pit and fissure Sealants in Primary and Permanent teeth - An In-Vitro Study

    PubMed Central

    Pushpalatha, H M; Ravichandra, K S; Srikanth, Koya; Divya, G; Done, Vasanthi; Krishna, K Bala; Patil, Vishwanath

    2014-01-01

    Background: Dental caries among children is one of the greatest challenges faced by dentists globally; especially that of susceptible surfaces like the Pit and fissures. Dental sealants have proved to be an effective way to prevent caries development. The Clinical success of any material depends upon its adhesion to tooth structure, resistance to wear and ability to withstand the masticatory or occlusal forces. Hence it is important to evaluate the shear bond strength (SBS). The Present study’s aim was to evaluate and compare the shear bond strength of different pit and fissure sealants placed on Primary molars and Permanent Premolars. Materials & Methods: Sixty noncarious extracted teeth comprising of thirty Primary molars and thirty Permanent Premolars were divided into four groups of 15 each. The buccal surfaces of all teeth were dried, etched and the etched surfaces of Primary molars (Group I) and Permanent Premolars (Group III) were placed with Helioseal-F while Groups II and IV, that included Primary molars and Permanent Premolars received Clinpro. Shear bond strength was evaluated and the mean was obtained for all the groups. The results were analyzed using twoway analysis of variance followed by Tukeys post hoc procedure to check for significant differences. Results: The specimens of unfilled sealant Clinpro (Groups II & IV) showed higher Shear bond strength when compared to the specimens of filled sealant Helioseal-F (Groups I & III). Conclusion: The unfilled sealant showed a better Shear bond strength compared to the filled sealant. The bond strength in Primary molars was slightly higher compared to Permanent Premolars. How to cite the article: Pushpalatha HM, Ravichandra KS, Srikanth K, Divya G, Done V, Krishna KB, Patil V. Comparative evaluation of Shear bond strength of different Pit and fissure Sealants in Primary and Permanent teeth - An In-Vitro Study. J Int Oral Health 2014;6(2):84-9. PMID:24876707

  15. Non-destructive measurement of demineralization and remineralization in the occlusal pits and fissures of extracted 3rd molars with PS-OCT

    NASA Astrophysics Data System (ADS)

    Lee, Chulsung; Hsu, Dennis J.; Le, Michael H.; Darling, Cynthia L.; Fried, Daniel

    2009-02-01

    Previous studies have demonstrated that Polarization Sensitive Optical Coherence Tomography (PS-OCT) can be used to image the remineralization of early artificial caries lesion on smooth enamel surfaces of human and bovine teeth. However, most new dental decay is found in the pits and fissures of the occlusal surfaces of posterior dentition and it is in these high risk areas where the performance of new caries imaging devices need to be investigated. The purpose of this study was to demonstrate that PS-OCT can be used to measure the subsequent remineralization of artificial lesions produced in the pits and fissures of extracted 3rd molars. A PS-OCT system operating at 1310-nm was used to acquire polarization resolved images of occlusal surfaces exposed to a demineralizing solution at pH-4.5 followed by a fluoride containing remineralizing solution at pH-7.0 containing 2-ppm fluoride. The integrated reflectivity was calculated to a depth of 200-µm in the entire lesion area using an automated image processing algorithm. Although a well-defined surface zone was clearly resolved in only a few of the samples that underwent remineralization, the PS-OCT measurements indicated a significant (p<0.05) reduction in the integrated reflectivity between the severity of the lesions that were exposed to the remineralization solution and those that were not. The lesion depth and mineral loss were also measured with polarized light microscopy and transverse microradiography after sectioning the teeth. These results show that PS-OCT can be used to non-destructively monitor the remineralization potential of anti-caries agents in the important pits and fissures of the occlusal surface.

  16. Transient Source Processes Prior to the March 2011 Kamoamoa Fissure Eruption, Kīlauea Volcano, Hawaíi

    NASA Astrophysics Data System (ADS)

    Lundgren, P.; Poland, M. P.; Miklius, A.; Anderson, K. R.

    2014-12-01

    Interferometric synthetic aperture radar (InSAR) and continuous GPS observations at the summit of Kīlauea Volcano, Hawaíi, show spatially and temporally transient surface displacements in the months and weeks before the 5-9 March 2011 Kamoamoa fissure eruption. Interferograms computed from the Italian Space Agency's COSMO-SkyMed satellites and the German Aerospace Center's TerraSAR-X satellite show a distinctive triangular pattern of surface deformation that extends to the SE of Kīlauea Caldera starting approximately one month prior to the Kamoamoa eruption. GPS and electronic tilt meter time series for sites in the vicinity of this deformation show that this inflation transient is superimposed on the longer (~4-6 month) summit inflation. We examine and model the spatiotemporal evolution of the summit deformation. InSAR data from ascending and descending tracks are used to constrain models of the transient. To achieve low-levels of atmospheric phase noise required interferograms spanning four months prior to the eruption, thus involving multiple sources within the summit region (see figure). To solve for model parameters we use a Markov Chain Monte Carlo optimization approach. First, we model the co-eruption summit deflation to isolate the intra-caldera sources, consisting of a steeply dipping tensile dislocation (D) beneath the western edge of the caldera and a sub-horizontal, NE trending spheroidal pressure source (Y) in the center of the caldera at 1.5 km depth. We use these sources as starting models for the pre-eruption transient, which requires the addition of a sill (S) to explain the deformation that extends to the SE of the caldera. In a third step we add a simplified model for Kīlauea's rifts and basal detachment system to explain the coupled summit and south flank motion. Modeled at over 3 km beneath the surface, the transient sill source inflates over the month before the eruption and deflates during the four-day eruption. The sill runs parallel to

  17. 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

  18. Superior Orbital Fissure Syndrome and Ophthalmoplegia Caused by Varicella Zoster Virus with No Skin Eruption in a Patient Treated with Tumor Necrosis Alpha Inhibitor

    PubMed Central

    Jensen, Helene; Thomsen, Sidsel Thorup; Hansen, Stine Scott; Munksgaard, Signe Bruun; Lindelof, Mette

    2015-01-01

    Varicella zoster virus lies dormant in the dorsal root ganglia after symptomatic chicken pox infection, usually in childhood. If the virus reactivates in the trigeminal ganglia, it can cause varicella zoster ophthalmicus, which can have severe ocular complications. We report a case of a 73-year-old woman in severe immunosuppression due to treatment with mycophenolate mofetil, glucocorticosteroids and a tumor necrosis factor alpha inhibitor. The reactivation caused superior orbital fissure syndrome, which has only rarely been described in relation to varicella zoster virus reactivation. In our case, the syndrome was seen along with severe encephalitis. PMID:26600786

  19. Bronchoscopic lung volume reduction with endobronchial valves for patients with heterogeneous emphysema and intact interlobar fissures (the BeLieVeR-HIFi trial): study design and rationale.

    PubMed

    Davey, C; Zoumot, Z; Jordan, S; Carr, D H; Polkey, M I; Shah, P L; Hopkinson, N S

    2015-03-01

    Although lung volume reduction surgery improves survival in selected patients with emphysema, there has been ongoing interest in developing and evaluating bronchoscopic approaches to try to reduce lung volumes with less morbidity and mortality. The placement of endobronchial valves is one such technique, and although some patients have had a significant improvement, responses have been inconsistent because collateral ventilation prevents lobar atelectasis. We describe the protocol of a trial (ISRCTN04761234) aimed to show that a responder phenotype, patients with heterogeneous emphysema and intact interlobar fissures on CT scanning, can be identified prospectively, leading to a consistent benefit in clinical practice. PMID:24664535

  20. Superior Orbital Fissure Syndrome and Ophthalmoplegia Caused by Varicella Zoster Virus with No Skin Eruption in a Patient Treated with Tumor Necrosis Alpha Inhibitor.

    PubMed

    Jensen, Helene; Thomsen, Sidsel Thorup; Hansen, Stine Scott; Munksgaard, Signe Bruun; Lindelof, Mette

    2015-01-01

    Varicella zoster virus lies dormant in the dorsal root ganglia after symptomatic chicken pox infection, usually in childhood. If the virus reactivates in the trigeminal ganglia, it can cause varicella zoster ophthalmicus, which can have severe ocular complications. We report a case of a 73-year-old woman in severe immunosuppression due to treatment with mycophenolate mofetil, glucocorticosteroids and a tumor necrosis factor alpha inhibitor. The reactivation caused superior orbital fissure syndrome, which has only rarely been described in relation to varicella zoster virus reactivation. In our case, the syndrome was seen along with severe encephalitis. PMID:26600786

  1. Glass ionomer ART sealant and fluoride-releasing resin sealant in fissure caries prevention – results from a randomized clinical trial

    PubMed Central

    2014-01-01

    Background The relative performance of ART sealant and fluoride-releasing resin sealant in preventing fissure caries in permanent molars was compared in a randomized clinical trial conducted in southern China (ClinicalTrials.gov NCT01829334). Methods After obtaining ethical approval, healthy schoolchildren who had permanent first molars with occlusal fissures which were sound but deep or presented with only incipient caries were recruited for the study. Included molars were randomly allocated into one of four parallel study groups in units of left/right teeth per mouth. Two of the four groups adopted the methods of ART or fluoride-releasing resin sealant placement while the other two groups adopted the topical fluoride application methods. Fissure status of the molars in each group was evaluated every 6 months. Development of dentine caries and sealant retention over 24 months in the molars in the two sealant-using groups was compared in this report. Outcome on cost-effectiveness of all four groups over 36 months will be reported elsewhere. Results At baseline, a total of 280 children (383 molars) with mean age 7.8 years were involved for the two sealant groups. After 24 months, 261 children (357 molars) were followed. Proportions of molars with dentine caries were 7.3% and 3.9% in the ART sealant and fluoride-releasing resin sealant groups, respectively (chi-square test, p = 0.171). Life-table survival analysis showed that sealant retention (full and partial) rate over 24 months for the resin sealant (73%) was significantly higher than that (50%) for the ART sealant (p < 0.001). Molar survival (no development of dentine caries) rates in the ART sealant (93%) and fluoride-releasing resin sealant (96%) groups were not significantly different (p = 0.169). Multilevel logistic regression (GEE modeling) accounting for the effects of data clustering and confounding factors confirmed this finding. Conclusions Though the retention of fluoride

  2. The Alarcón Rise: detail mapping and preliminary results on the geometry, distribution and kinematics of faults and fissures on a ridge-transform system

    NASA Astrophysics Data System (ADS)

    Spelz, R. M.; Fletcher, J. M.; Nieves-Cardoso, C.; Santa Rosa-del Rio, M.; Caress, D. W.; Clague, D. A.; Paduan, J. B.; Martin, J. F.; Guardado-France, R.

    2012-12-01

    The Alarcón Rise, the northernmost segment of the East Pacific Rise before it enters the Gulf of California, is the oldest and perhaps most active spreading ridge-transform system along the oblique-divergent Pacific-North America plate boundary in the southern Gulf of California. Magnetic anomalies along the main ridge axis, which stretches for nearly 50 km long in a NE-SW (034o) direction, suggest that spreading with new oceanic crust was fully established ca. 2.5 Ma, and that its modern configuration as the main plate boundary initiated ca. 2 Ma (Umhoefer, P.J. et al., 2007 Basin Research). High resolution (1m lateral/0.2m vertical) bathymetry data and direct observations of the entire ridge segment, collected and performed by MBARI's autonomous underwater vehicle (AUV) and ROV dives, respectively, during the 2012 Expedition to the Gulf of California, have revealed the presence of an intense array of fault-scarps and fissures displacing numerous neovolcanic landforms such as huge lava domes and smaller cones, pillow mounds and large sheet flows along the entire ridge. The relative age of the surface ruptures is wide-ranging. At some places the fractures appear to be relatively recent, as evident by the apparent young age of the fractured flows, based on having few sessile organisms and/or relatively thin sediment cover. In contrast, fractures and fault-scarps elsewhere are observed to have been partially or totally overrun by lava flows, suggesting their preexistence and relatively older age. The ridge parallel faults and fissures change orientation dramatically as they approach and wrap around the bordering Pescadero and Tamayo fracture zones, which limit the northern and southern flanks of the rise, respectively, giving the ridge a sigmoidal geometry with a Z-shaped symmetry. Moreover, the presence of an en echelon volcanic fissure system near the southern end of the ridge, measuring several kilometers long and oriented somewhat obliquely (~15o clockwise) to

  3. 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.

  4. Enhancing caries resistance in occlusal fissures with a short-pulsed CO2 9.6-μm laser: an in vitro pH-cycling study, preliminary results

    NASA Astrophysics Data System (ADS)

    Charland, Daniel; Fulton, Crystal; Rechmann, Beate; Hewko, Mark; Featherstone, John; Choo-Smith, Lin-P'ing; Rechmann, Peter

    2011-03-01

    Treatment of occlusal surfaces with a short-pulsed CO2 9.6 μm wavelength laser has previously been proposed as a method for caries prevention. A sample of 20 extracted human molars were measured before and after demineralizationremineralization pH-cycling with ICDAS II visual inspection, DIAGNOdent, quantitative light-induced fluorescence (QLF), SoproLife in daylight and blue light-induced fluorescence mode, optical coherence tomography (OCT) and polarized Raman spectroscopy (PRS). Per tooth, one fissure was subjected to laser treatment using a short-pulsed CO2 laser at 9.6 μm wavelength with a fluence of 3.5 J/cm2, 20 Hz pulse repetition rate, 20 μs pulse duration, angulated handpiece, and focus diameter of 600 μm, while the other fissure was left untreated as control. The teeth were subjected to a demineralization-remineralization pH-cycling for 9 days. Cross-sectional micro-hardness testing was done as a gold standard to compare results with findings from the other detection methods used. Due to the small sample size reported, the trend observed was that laser treated fissures demonstrated a smaller relative mineral loss ▵Z than the controls. QLF findings followed a similar trend. Using a rotary catheter probe, OCT measurements were acquired from the various fissures to generate circularly mapped OCT depth images. PRS measurements of parallel- and cross-polarized spectra were acquired with a Raman microscope system. Preliminary OCT images showed differences in the initial air-tooth interface, with PRS results indicating a change in the surface property along with biochemical alterations after pH-cycling. Following pH-cycling, an increase in the OCT subsurface light backscattering intensity in the control fissures was observed compared to the laser test fissures. Porphyrin based fluorescence methods like DIAGNOdent and SoproLife, respectively demonstrated only additional light scattering due to the demineralization process.

  5. Long-distance magma transport from arc volcanoes inferred from the submarine eruptive fissures offshore Izu-Oshima volcano, Izu-Bonin arc

    NASA Astrophysics Data System (ADS)

    Ishizuka, Osamu; Geshi, Nobuo; Kawanabe, Yoshihisa; Ogitsu, Itaru; Taylor, Rex N.; Tuzino, Taqumi; Sakamoto, Izumi; Arai, Kohsaku; Nakano, Shun

    2014-09-01

    Long-distance lateral magma transport away from volcanic centers in island arcs is emerging as a common phenomenon where the regional stress regime is favorable. It should also be recognized as an important factor in the construction and growth of island arcs, and a potential trigger for devastating eruptions. In this contribution, we report on recent investigations into the magma dynamics of Izu-Oshima volcano, an active basaltic volcano with an extensive fissure system. Izu-Oshima is flanked by numerous, subparallel NW-SE trending submarine ridges extending up to 22 km to the NW and the SE from the central vent. During a recent submersible survey we have identified that these ridges are fissures which erupted basaltic spatter and lava flows. Furthermore, lavas are petrographically similar along each ridge, while there are noticeable differences between ridges. The subparallel ridges are observed to transect a series of seamounts - the Izu-Tobu monogenetic volcanoes - which are dispersed across this area of the rear-arc. However, there are consistent petrographic and chemical differences between these seamounts and the ridges, indicating that they have different magma sources, yet, they are essentially bounding each other in dive tracks. The most appropriate scenario for their development is one where the Izu-Tobu Volcanoes are fed by an "in-situ" underlying source, while the NW-SE ridges are fed by lateral magma transport from Izu-Oshima. Magma erupted from each ridge is of a consistent geochemistry along its length, but has experienced crystal fractionation and some plagioclase accumulation. Compositions of the ridges are also very similar to lavas from the subaerial cones that can be traced down the flanks of Izu-Oshima. This implies that pairs of subaerial cones and submarine ridges represent the locus of magma transport events away from the storage system beneath Izu-Oshima. Hence, magma from this crustal reservoir moved upward to feed the on-edifice cones

  6. Automatic classification of pulmonary peri-fissural nodules in computed tomography using an ensemble of 2D views and a convolutional neural network out-of-the-box.

    PubMed

    Ciompi, Francesco; de Hoop, Bartjan; van Riel, Sarah J; Chung, Kaman; Scholten, Ernst Th; Oudkerk, Matthijs; de Jong, Pim A; Prokop, Mathias; van Ginneken, Bram

    2015-12-01

    In this paper, we tackle the problem of automatic classification of pulmonary peri-fissural nodules (PFNs). The classification problem is formulated as a machine learning approach, where detected nodule candidates are classified as PFNs or non-PFNs. Supervised learning is used, where a classifier is trained to label the detected nodule. The classification of the nodule in 3D is formulated as an ensemble of classifiers trained to recognize PFNs based on 2D views of the nodule. In order to describe nodule morphology in 2D views, we use the output of a pre-trained convolutional neural network known as OverFeat. We compare our approach with a recently presented descriptor of pulmonary nodule morphology, namely Bag of Frequencies, and illustrate the advantages offered by the two strategies, achieving performance of AUC = 0.868, which is close to the one of human experts. PMID:26458112

  7. Observations of a substantial cloud-aerosol indirect effect during the 2014-2015 Bárðarbunga-Veiðivötn fissure eruption in Iceland

    NASA Astrophysics Data System (ADS)

    McCoy, Daniel T.; Hartmann, Dennis L.

    2015-12-01

    The Bárðarbunga-Veiðivötn fissure eruption lasted from 31 August 2014 to 28 February 2015, during which its sulfur emissions dwarfed anthropogenic emissions from Europe. This natural experiment offers an excellent opportunity to investigate the aerosol indirect effect and the effect of effusive volcanic eruptions on climate. During the eruption cloud droplet effective radius (re) over the region surrounding Iceland was at the lowest value in the 14 year Moderate Imaging Spectroradiometer data record during September and October 2014. The change in reflected solar radiation due to increased cloud reflectivity during September and October is estimated to exceed 2 W m-2 over the region surrounding Iceland, with increases of 1 W m-2 extending as far south as the Açores. The strength of the aerosol indirect effect diagnosed here reaffirms the ability of volcanic aerosols to affect cloud properties and ultimately the planetary albedo.

  8. A Comparative Evaluation of the Effect of Bonding Agent on the Tensile Bond Strength of Two Pit and Fissure Sealants Using Invasive and Non-invasive Techniques: An in–vitro Study

    PubMed Central

    Singh, Shamsher; Adlakha, Vivek; Babaji, Prashant; Chandna, Preetika; Thomas, Abi M.; Chopra, Saroj

    2013-01-01

    Background: Newer technologies and the development of pit and fissure sealants have shifted the treatment philosophy from ‘drill and fill’ to that of ‘seal and heal’. Aims: The purpose of this in–vitro study was to evaluate the effects of bonding agents on the tensile bond strengths of two pit and fissure sealants by using invasive and non-invasive techniques. Study Design and Methods: One hundred and twenty bicuspids were collected and teeth were divided into two groups: Group-I (Clinpro) and Group-II (Conseal f) with 60 teeth in each group. For evaluating tensile bond strengths, occlusal surfaces of all the teeth were flattened by reducing buccal and lingual cusps without disturbing fissures. Standardised polyvinyl tube was bonded to occlusal surfaces with respective materials. Sealants were applied, with or without bonding agents, in increments and they were light cured. Tensile bond strengths were determined by using Universal Testing Machine. Statistical Analysis: Data were then statistically analysed by using Student t–test for comparison. Results: A statistically significant difference was found in tensile bond strength in invasive with bonding agent group than in non-invasive with bonding agent group. Conclusion: This study revealed that invasive techniques increase the tensile bond strengths of sealants as compared to non- invasive techniques and that the use of a bonding agent as an intermediate layer between the tooth and fissure sealant is beneficial for increasing the bond strength. PMID:24298525

  9. Caries-preventive effect of glass ionomer and resin-based fissure sealants on permanent teeth: An update of systematic review evidence

    PubMed Central

    2011-01-01

    Background This article constitutes a partial update of the original systematic review evidence by Yengopal et al. from 15 January 2008 (published in the Journal of Oral Science in 2009) with primary focus on research quality in regard to bias risk in trials. Its aim is to update the existing systematic review evidence from the English literature as to whether caries occurrence on pits and fissures of teeth sealed with either GIC or resin is the same. Methods In addition to the 12 trials included during the original systematic review, 5 new trials were identified during the database search (up to 26 August 2010) and 2 further trials were included from a hand search and reference check. Of these, 3 trials were excluded and 16 were accepted for data extraction and quality assessment. The quality of accepted trials was assessed, using updated quality criteria, and the risk of bias was investigated in more depth than previously reported. In addition, the focus of quantitative synthesis was shifted to single datasets that were extracted from the accepted trials. Results Twenty-six dichotomous and 4 continuous datasets were extracted. Meta-analysis and cumulative meta-analysis were used in combining clinically homogenous datasets. The overall outcome of the computed datasets suggest no difference between the caries-preventive effects of GIC- and resin-based fissure sealants. Conclusions This overall outcome is in agreement with the conclusions of the original systematic review. Although the findings of the trials identified in this update may be considered to be less affected by attrition- and publication bias, their risk of selection- and detection-/performance bias is high. Thus, verification of the currently available results requires further high quality randomised control trials. PMID:21276215

  10. Simulating the propagation of sulphur dioxide emissions from the fissure eruption in the Holuhraun lava field (Iceland) with the EURAD-IM

    NASA Astrophysics Data System (ADS)

    Fröhlich, Luise; Franke, Philipp; Friese, Elmar; Haas, Sarah; Lange, Anne Caroline; Elbern, Hendrik

    2015-04-01

    In the emergency case of a volcano eruption accurate forecasts of the transport of ash and gas emissions are crucial for health protection and aviation safety. In the frame of Earth System Knowledge Platform (ESKP) near real-time forecasts of ash and SO2 dispersion emitted by active volcanoes are simulated by the European Air pollution Dispersion Inverse Model (EURAD-IM). The model is driven by the Weather Research and Forecasting Model (WRF) and includes detailed gas phase and particle dynamics modules, which allow for quantitative estimates of measured volcano releases. Former simulations, for example related to the Eyjafjallajökull outbreak in 2010, were in good agreement with measurement records of particle number and SO2 at several European stations. At the end of August 2014 an fissure eruption has begun on Iceland in the Holuhraun lava field to the north-east of the Bardarbunga volcano system. In contrast to the explosive eruption of the Eyjafjallajökull in 2010, the Holuhraun eruption is rather effusive with a large and continuous flow of lava and a significant release of sulphur dioxide (SO2) in the lower troposphere, while ash emissions are insignificant. Since the Holuhraun fissure eruption has started, daily forecasts of SO2 dispersion are produced for the European region (15 km horizontal resolution grid) and published on our website (http://apps.fz-juelich.de/iek-8/RIU/vorhersage_node.php). To simulate the transport of volcanic emissions, realistic source terms like mass release rates of ash and SO2 or plume heights are required. Since no representative measurements are currently available for the simulations, rough qualitative assumptions, based on reports from the Icelandic Met Office (IMO), are used. However, frequent comparisons with satellite observations show that the actual propagation of the volcanic emissions is generally well reflected by the model. In the middle of September 2014 several European measurement sides recorded extremely high