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Sample records for applied occlusal load

  1. Determining a relationship between applied occlusal load and articulating paper mark area.

    PubMed

    Carey, Jason P; Craig, Mark; Kerstein, Robert B; Radke, John

    2007-01-01

    Articulating paper mark size has been widely accepted in the dental community to be descriptive of occlusal load. The objective of this study is to determine if any direct relationship exists between articulating paper mark area and applied occlusal load. A uniaxial testing machine repeatedly applied a compressive load, beginning at 25N and incrementally continuing up to 450N, to a pair of epoxy dental casts with articulating paper interposed. The resultant paper markings (n = 600) were photographed, and analyzed the mark area using a photographic image analysis and sketching program. A two-tailed Student's t-test for unequal variances compared the measured size of the mark area between twelve different teeth (p < 0.05). Graphical interpretation of the data indicated that the mark area increased non-linearly with increasing load. When the data was grouped to compare consistency of the mark area between teeth, a high variability of mark area was observed between different teeth at the same applied load. The Student's t-test found significant differences in the size of the mark area approximately 80% of the time. No direct relationship between paper mark area and applied load could be found, although the trend showed increasing mark area with elevating load. When selecting teeth to adjust, an operator should not assume the size of paper markings, accurately describing the markings' occlusal contact force content.

  2. Determining a Relationship Between Applied Occlusal Load and Articulating Paper Mark Area

    PubMed Central

    Carey, Jason P; Craig, Mark; Kerstein, Robert B; Radke, John

    2007-01-01

    Articulating paper mark size has been widely accepted in the dental community to be descriptive of occlusal load. The objective of this study is to determine if any direct relationship exists between articulating paper mark area and applied occlusal load. A uniaxial testing machine repeatedly applied a compressive load, beginning at 25N and incrementally continuing up to 450N, to a pair of epoxy dental casts with articulating paper interposed. The resultant paper markings (n = 600) were photographed, and analyzed the mark area using a photographic image analysis and sketching program. A two-tailed Student’s t-test for unequal variances compared the measured size of the mark area between twelve different teeth (p < 0.05). Graphical interpretation of the data indicated that the mark area increased non-linearly with increasing load. When the data was grouped to compare consistency of the mark area between teeth, a high variability of mark area was observed between different teeth at the same applied load. The Student’s t-test found significant differences in the size of the mark area approximately 80% of the time. No direct relationship between paper mark area and applied load could be found, although the trend showed increasing mark area with elevating load. When selecting teeth to adjust, an operator should not assume the size of paper markings, accurately describing the markings’ occlusal contact force content. PMID:19088874

  3. Effects of occlusal load on cervical lesions.

    PubMed

    Litonjua, L A; Bush, P J; Andreana, S; Tobias, T S; Cohen, R E

    2004-03-01

    Toothbrush abrasion has been considered to cause cervical lesions. However, some investigators have proposed that occlusal loading factors direct tensile stresses at the cervical area, resulting in wedge-shaped abfraction defects. The purpose of this study is to investigate the role of axial and non-axial load on the development of cervical lesions. Matched paired premolars, extracted for orthodontic purposes, were used in a custom-fabricated toothbrushing apparatus. A periodontal sulcus width of 0b1 mm with 1 mm gingival recession was simulated with denture base resin. In phase 1, eight matched premolar pairs were subjected to 80 h (1b4 million strokes) of brushing and 300 g of toothbrush force. Toothpaste slurry was applied continuously through the toothbrush. One specimen in each pair was subjected to 250 h and 45 kg of continuous axial load, while the other unloaded tooth served as a negative control. In phase 2, 10 matched premolar pairs were subjected to the same conditions; however, the experimental teeth were subjected to 250 h and 45 kg of intermittent non-axial load, directed at a 45 degrees angle to the buccal cusp. Rubber impressions were made of the cervical lesions, then trimmed, weighed, and compared to determine the amount of tooth material lost. When teeth were loaded axially, there was significantly less tooth material loss (P < 0b02); however, when teeth were loaded non-axially, there was no significant difference (P =0b80) when compared with controls. Optical and scanning electron microscopy did not reveal any significant differences in the morphology between pairs. Our data suggest that the application of occlusal load may not necessarily play a significant role in the progression of cervical tooth wear commonly referred to as abfraction.

  4. Effects of vascular occlusion on muscular endurance in dynamic knee extension exercise at different submaximal loads.

    PubMed

    Wernbom, Mathias; Augustsson, Jesper; Thomeé, Roland

    2006-05-01

    Strength training with low load under conditions of vascular occlusion has been proposed as an alternative to heavy-resistance exercise in the rehabilitation setting, when large forces acting upon the musculoskeletal system are unwanted. Little is known, however, about the relative intensity at which occlusion of blood flow significantly reduces dynamic muscular endurance and, hence, when it may increase the training effect. The purpose of this study was to investigate endurance during dynamic knee extension at different loads with and without cuff occlusion. Sixteen subjects (20-45 years of age) with strength-training experience were recruited. At 4 test sessions, the subjects performed unilateral knee extensions to failure with and without a pressure cuff around the thigh at 20, 30, 40, and 50% of their 1 repetition maximum (1RM). The pressure cuff was inflated to 200 mm Hg during exercise with occlusion. Significant differences in the number of repetitions performed were found between occluded and nonoccluded conditions for loads of 20, 30, and 40% of 1RM (p < 0.01) but not for the 50% load (p = 0.465). Thus, the application of a pressure cuff around the thigh appears to reduce dynamic knee extension endurance more at a low load than at a moderate load. These results may have implications regarding when it could be useful to apply a tourniquet in order to increase the rate of fatigue and perhaps also the resulting training effect. However, the short- and long-term safety of training under ischemic conditions needs to be addressed in both healthy and less healthy populations. Furthermore, the high acute pain ratings and the delayed-onset muscle soreness associated with this type of training may limit its potential use to highly motivated individuals.

  5. Evaluation of the cervical integrity during occlusal loading of Class II restorations.

    PubMed

    Campos, Paulo Eduardo Gomes de Almeida; Barceleiro, Marcos de Oliveira; Sampaio-Filho, Helio Rodrigues; Martins, Luis Roberto Marcondes

    2008-01-01

    There are many concerns regarding the clinical behavior of packable composite restorations in Class II cavities, particularly when those restorations are subjected to axial mechanical loads. This study evaluated microleakage in vitro in proximal vertical "slot"-type cavities with walls located in enamel and dentin, filled with packable composite, associated or not associated with a flowable composite, a reinforced light-curing glass-ionomer or a compomer, after being submitted to occlusal load cycling. These preparations were subjected to either occlusal load cycling or no occlusal load cycling. Eighty human molars with enamel and dentin margins were treated with standardized cavity preparations (proximal vertical "slot" preparations). After completing the filling process using a packable composite (Filtek P60) with or without a cervical increment of flowable composite (Filtek flow), light-curing glass-ionomer (Vitremer) or compomer (Dyract AP), the molars were separated into two groups: control (without occlusal loading) and test, in which 4,000 one-second cycles of 150 N occlusal loading were applied. All 80 teeth were submitted to a microleakage test, then evaluated utilizing silver nitrate dye penetration. Significant statistical differences (Wilcoxon test, p<0.05) in the amount of leakage in enamel and dentin were found in both the control and test groups. After a paired comparison of the control and test groups, a significant statistical difference was found at the enamel level (Mann-Whitney test, p<0.05). In dentin, the only statistically significant difference found was the relation to the flow material. The Kruskal-Wallis test did not detect any statistically significant difference in the amount of leakage among the four materials studied, with a 5% level of significance for both enamel and dentin. Based on this data, it was concluded that restorations with margins located in dentin had greater microleakage than those restorations with margins located in

  6. The effect of variation in occlusal loading on the development of abfraction lesions: a finite element study.

    PubMed

    Rees, J S

    2002-02-01

    Abfraction or non-carious cervical tooth loss is poorly understood and one factor thought to contribute to the development of these lesions is the effect of occlusal loading. The aim of this study was to examine the effect that varying the position of an occlusal load would have on the stress contour in the cervical region of a lower second premolar using a two-dimensional plane strain finite element model. A 500 N load was applied vertically to either of the cusp tips or in various positions along the cuspal inclines. It was found that loads applied to the inner aspects of the buccal or the lingual cuspal inclines produced maximum principal stress values of up to 358 MPa that exceed the known failure stresses for enamel.

  7. Load-bearing properties of minimal-invasive monolithic lithium disilicate and zirconia occlusal onlays: finite element and theoretical analyses

    PubMed Central

    Ma, Li; Guess, Petra C.; Zhang, Yu

    2013-01-01

    Objectives The aim of this study was to test the hypothesis that monolithic lithium disilicate glass-ceramic occlusal onlay can exhibit a load-bearing capacity that approaches monolithic zirconia, due to a smaller elastic modulus mismatch between the lithium disilicate and its supporting tooth structure relative to zirconia. Methods Ceramic occlusal onlays of various thicknesses cemented to either enamel or dentin were considered. Occlusal load was applied through an enamel-like deformable indenter or a control rigid indenter. Flexural tensile stress at the ceramic intaglio (cementation) surface—a cause for bulk fracture of occlusal onlays—was rigorously analyzed using finite element analysis and classical plate-on-foundation theory. Results When bonded to enamel (supported by dentin), the load-bearing capacity of lithium disilicate can approach 75% of that of zirconia, despite the flexural strength of lithium disilicate (400 MPa) being merely 40% of zirconia (1000 MPa). When bonded to dentin (with the enamel completely removed), the load-bearing capacity of lithium disilicate is about 57% of zirconia, still significantly higher than the anticipated value based on its strength. Both ceramics show slightly higher load-bearing capacity when loaded with a deformable indenter (enamel, glass-ceramic, or porcelain) rather than a rigid indenter. Significance When supported by enamel, the load-bearing property of minimally invasive lithium disilicate occlusal onlays (0.6 to 1.4 mm thick) can exceed 70% of that of zircona. Additionally, a relatively weak dependence of fracture load on restoration thickness indicates that a 1.2 mm thin lithium disilicate onlay can be as fracture resistant as its 1.6 mm counterpart. PMID:23683531

  8. Influence of occlusal loading on peri-implant clinical parameters. A pilot study

    PubMed Central

    Pellicer-Chover, Hilario; Viña-Almunia, José; Romero-Millán, Javier; Peñarrocha-Oltra, David; Peñarrocha-Diago, María

    2014-01-01

    Objectives: To investigate the relation between occlusal loading and peri-implant clinical parameters (probing depth, bleeding on probing, gingival retraction, width of keratinized mucosa, and crevicular fluid volume) in patients with implant-supported complete fixed prostheses in both arches. Material and Methods: This clinical study took place at the University of Valencia (Spain) dental clinic. It included patients attending the clinic for regular check-ups during at least 12 months after rehabilitation of both arches with implant-supported complete fixed ceramo-metallic prostheses. One study implant and one control implant were established for each patient using the T-Scan®III computerized system (Tesco, South Boston, USA). The maxillary implant closest to the point of maximum occlusal loading was taken as the study implant and the farthest (with least loading) as the control. Occlusal forces were registered with the T-Scan® III and then occlusal adjustment was performed to distribute occlusal forces correctly. Peri-implant clinical parameters were analyzed in both implants before and two and twelve months after occlusal adjustment. Results: Before occlusal adjustment, study group implants presented a higher mean volume of crevicular fluid (51.3±7.4 UP) than the control group (25.8±5.5 UP), with statistically significant difference. Two months after occlusal adjustment, there were no significant differences between groups (24.6±3.8 UP and 26±4.5 UP respectively) (p=0.977). After twelve months, no significant differences were found between groups (24.4±11.1 UP and 22.5±8.9 UP respectively) (p=0.323). For the other clinical parameters, no significant differences were identified between study and control implants at any of the study times (p>0.05). Conclusions: Study group implants receiving higher occlusal loading presented significantly higher volumes of crevicular fluid than control implants. Crevicular fluid volumes were similar in both groups two and

  9. Contact fracture of full-ceramic crowns subjected to occlusal loads.

    PubMed

    Zhang, Dongsheng; Lu, Chenglin; Zhang, Xiuyin; Mao, Shuangshuang; Arola, Dwayne

    2008-10-20

    The mechanisms contributing to failure of full dental ceramic crowns under occlusal loads were studied using a unique optical approach. Model specimens comprising triple-layered crowns (veneer, core and substrate) were developed with both flat and curved occlusal surfaces and then subjected to simulated quasi-static occlusal loading using a spherical indenter. Deformation within the specimens during loading was analyzed by means of digital image correlation (DIC). Finite element models were also developed and used to examine the mechanics of contact. Results of the experiments with flat dental crowns indicated three typical modes of failure, i.e. cone cracks, plastic yielding and radial cracks. Fracture of the specimens with curved dental crowns was complicated by contributions from competing and multiple modes of failure. Both experimental and numerical results conclude that the dominant fracture mode in the full-ceramic crowns was radial cracking in the core beneath the contact area. However, displacement fields obtained using DIC showed that debonding developed near the shoulder of the crown, particularly during off-axis loading, and initiated under substantially lower occlusal loads than those required for crack initiation.

  10. Estrogen Receptor beta mediates decreased occlusal loading induced inhibition of chondrocyte maturation in female mice

    PubMed Central

    Polur, Ilona; Kamiya, Yosuke; Xu, Manshan; Cabri, Bianca S.; Alshabeeb, Marwa; Wadhwa, Sunil; Chen, Jing

    2015-01-01

    Objective Temporomandibular joint (TMJ) disorders predominantly afflict women, suggesting that estrogen may play a role in the disease process. Defects in mechanical loading-induced TMJ remodeling are believed to be a major etiological factor in TMJ degenerative disease. Previously, we found that, decreased occlusal loading caused a significant decrease in early chondrocyte maturation markers (Sox9 and Col 2) in female, but not male, C57BL/6 wild type mice (1). The goal of this study was to examine the role of Estrogen Receptor (ER) beta in mediating these effects. Design 21-day-old male (n=24) and female (n=25) ER beta KO mice were exposed to decreased occlusal loading (soft diet administration and incisor trimming) for 4 weeks. At 49 days of age the mice were sacrificed. Proliferation, gene expression, Col 2 immunohistochemistry and micro-CT analysis were performed on the mandibular condyles. Results Decreased occlusal loading triggered similar effects in male and female ER beta KO mice; specifically, significant decreases in Col 10 expression, subchondral total volume, bone volume, and trabecular number. Conclusion Decreased occlusal loading induced inhibition of chondrocyte maturation markers (Sox9 and Col 2) did not occur in female ER beta deficient mice. PMID:25791327

  11. Retention of complete maxillary dentures measured as resistance against unilateral occlusal loading.

    PubMed

    Fløystrand, F; Orstavik, J S

    1984-02-01

    Complete maxillary dentures were tested for their ability to remain in place when subjected to unilateral occlusal loads. The test material comprised five persons, each supplied with three identical dentures. The denture design was based on the principles of 1) functionally determined filling-in of the vestibular sulcus, 2) palatal coverage to the vibration line without post dam, 3) aesthetically governed positioning of the front teeth, and 4) positioning of the lateral teeth in the plane connecting the top of the residual ridge with the central part of the occlusal surface of the antagonizing natural teeth. Resistance to unilateral occlusal loads was measured by means of a miniature bite force sensor. In the pooled material, an average load of 70 N was tolerated before the dentures were dislodged. For a given participant/denture combination, the resistance against dislodgment varied considerably when tested on different days. Marked differences were also found among three identical dentures in one person. The tolerance against unilateral occlusal loads could feasibly be quantified. However, the influence of specific clinical and/or technological factors on denture retention during function should be studied only if strict definitions as to the test conditions are given. These conditions must include the time, person, and denture tested.

  12. Low-Load Resistance Training with Blood Flow Occlusion as a Countermeasure to Disuse Atrophy

    NASA Technical Reports Server (NTRS)

    Ploutz-Snyder, L. L.; Cook, S. B.

    2009-01-01

    Decreases in strength and neuromuscular function are observed following prolonged disuse. Exercise countermeasures to prevent muscle dysfunction during disuse typically involve high intensity resistance training. The purpose of the study is to evaluate the effectiveness of low-load resistance training with a blood flow occlusion to mitigate muscle loss and dysfunction during 30 days of unilateral lower limb suspension (ULLS).

  13. Bonding of flowable resin composite restorations to class 1 occlusal cavities with and without cyclic load stress.

    PubMed

    Kawai, Takatoshi; Maseki, Toshio; Nara, Yoichiro

    2016-01-01

    To examine the bonding of flowable resin composite restorations (F-restoration) to class 1 occlusal cavities with and without cyclic load stress, compared with that of a universal resin composite restoration (U-restoration). Two flowable composites and one universal composite (control) were applied with an adhesive system to 42 standardized class 1 occlusal cavities. The restored specimens were subjected to cyclic load stress and no stress modes. The microtensile bond strength (μ-TBS) of the dentin floor was measured. The U-restoration did not show pretesting failure. The F-restorations exhibited pretesting failure, regardless of the stress mode. The μ-TBS was not significantly different among the three restorations, regardless of the stress mode. The cyclic load stress did not influence the μ-TBS of the F-restorations; however, it significantly reduced μ-TBS in the U-restoration. The bonding reliability of the F-restorations was inferior to that of the U-restoration, for both stress modes.

  14. Micro-tensile bond strength of adhesive systems applied on occlusal primary enamel.

    PubMed

    Ramires-Romito, Ana Cláudia; Reis, Alessandra; Loguercio, Alessandro Dourado; de Góes, Mario Fernando; Grande, Rosa Helena Miranda

    2004-01-01

    The aim of this study was to evaluate the micro-tensile bond strength of adhesive systems (OptiBond Solo, Kerr; Prime & Bond NT, Dentsply) on occlusal surface of primary molars. The adhesives were tested under manufacturers' specifications and after contamination of the bonding site with saliva. Hourglass cylindrical-shaped samples were obtained and subjected to a tensile force. No significant difference was observed among the groups. OptiBond Solo and Prime & Bond NT showed similar values of bond strengths when applied on occlusal enamel of primary molar under either saliva contamination or not.

  15. Microstructural properties of the mid-facial bones in relation to the distribution of occlusal loading.

    PubMed

    Janovic, Aleksa; Milovanovic, Petar; Saveljic, Igor; Nikolic, Dalibor; Hahn, Michael; Rakocevic, Zoran; Filipovic, Nenad; Amling, Michael; Busse, Bjoern; Djuric, Marija

    2014-11-01

    Although the concept of the occlusal load transfer through the facial skeleton along the buttresses has been extensively studied, there has been no study to link microarchitecture of the mid-facial bones to the occlusal load distribution. The aim of this study was to analyze micro-structural properties of the mid-facial bones in relation to occlusal stress. The study was performed by combining the three-dimensional finite element analysis (3D FEA) and micro-computed tomography analysis (micro-CT). Clenching was simulated on the computer model of the adult male human skull which was also used as a source of bone specimens. After the FEA was run, stress was measured at the specific sites in cortical shell and trabecular bone of the model along and between the buttresses. From the corresponding sites on the skull, twenty-five cortical and thirteen cancellous bone specimens were harvested. The specimens were classified into high stress or low stress group based on the stress levels measured via the FEA. Micro-architecture of each specimen was assessed by micro-CT. In the high stress group, cortical bone showed a tendency toward greater thickness and density, lower porosity, and greater pore separation. Stress-related differences in microstructure between the groups were more pronounced in trabecular bone, which showed significantly greater bone volume fraction (BV/TV) and trabecular thickness (Tb.Th) in the high stress group. Our results suggest that the mid-facial bones in the adult dentate male skull exhibit regional variations in cortical and trabecular bone micro-architecture that could be a consequence of different occlusal stress.

  16. Effect of transient occlusal loading on the threshold of tooth tactile sensation perception for tapping like the impulsive stimulation.

    PubMed

    Morimoto, Yuta; Oki, Kazuhiro; Iida, Sachiyo; Shirahige, Chieko; Maeda, Naoto; Kawakami, Shigehisa; Matsunaga, Tadashi; Minagi, Shogo

    2013-07-01

    The objectives of this study were (1) to establish a reliable method for detecting the force threshold of the tooth tactile sensation while avoiding experimenter bias and (2) to examine the effect of occlusal force loading on the threshold for impulsive force stimulation in subjects with normal dentition. Twenty volunteers participated in this study (10 males and 10 females; mean age, 26.6 ± 2.9 years). To simulate the bite force during occlusal tapping, a force-loading device was designed to exert impulsive force to the occlusal surface in the direction parallel to the tooth axis. The impulsive force detection threshold of the periodontal sensation was measured before and after loading 98 N of occlusal force on the left upper first molar for 1 min. Transient mechanical loading of the upper first molar caused an increase in the absolute threshold for impulsive force. This increase did not vanish immediately, and the increment of the threshold was maintained during the remainder of the experiment. A computer-controlled method for the evaluation of tooth tactile sensation using impulsive stimulation was established. Transient occlusal force loading parallel to the tooth axis increases the threshold of periodontal sensation for mechanical impulsive stimulation.

  17. Effects of low-load resistance training with vascular occlusion on the mechanical properties of muscle and tendon.

    PubMed

    Kubo, Keitaro; Komuro, Teruaki; Ishiguro, Noriko; Tsunoda, Naoya; Sato, Yoshiaki; Ishii, Naokata; Kanehisa, Hiroaki; Fukunaga, Tetsuo

    2006-05-01

    The present study aimed to investigate the effects of low-load resistance training with vascular occlusion on the specific tension and tendon properties by comparing with those of high-load training. Nine participants completed 12 weeks (3 days/week) of a unilateral isotonic training program on knee extensors. One leg was trained using low load (20% of 1 RM) with vascular occlusion (LLO) and other leg using high load (80% of 1 RM) without vascular occlusion (HL). Before and after training, maximal isometric knee extension torque (MVC) and muscle volume were measured. Specific tension of vastus lateralis muscle (VL) was calculated from MVC, muscle volume, and muscle architecture measurements. Stiffness of tendon-aponeurosis complex in VL was measured using ultrasonography during isometric knee extension. Both protocols significantly increased MVC and muscle volume of quadriceps femoris muscle. Specific tension of VL increased significantly 5.5% for HL, but not for LLO. The LLO protocol did not alter the stiffness of tendon-aponeurosis complex in knee extensors, while the HL protocol increased it significantly. The present study demonstrated that the specific tension and tendon properties were found to remain following low-load resistance training with vascular occlusion, whereas they increased significantly after high-load training.

  18. Effects of partial vascular occlusion on irisin responses to loaded muscle contractions.

    PubMed

    Kraemer, Robert R; Goldfarb, Allan H; Reeves, Greg V; Meachum, William A; Castracane, V Daniel

    2016-03-01

    The purpose of the study was to determine the effects of partial vascular occlusion on irisin responses. Eight males completed trials of light (30% 1-repetition maximum (1RM)) resistance exercise (single biceps curls and calf presses) with partial vascular occlusion (LRO), moderate resistance (70% 1RM) with no occlusion (MR), and occlusion only (OO). Blood was collected before, after, and 15 min after exercise. Changes in circulating irisin were more affected during LRO than MR and OO trials.

  19. Occlusal load distribution through the cortical and trabecular bone of the human mid-facial skeleton in natural dentition: a three-dimensional finite element study.

    PubMed

    Janovic, Aleksa; Saveljic, Igor; Vukicevic, Arso; Nikolic, Dalibor; Rakocevic, Zoran; Jovicic, Gordana; Filipovic, Nenad; Djuric, Marija

    2015-01-01

    Understanding of the occlusal load distribution through the mid-facial skeleton in natural dentition is essential because alterations in magnitude and/or direction of occlusal forces may cause remarkable changes in cortical and trabecular bone structure. Previous analyses by strain gauge technique, photoelastic and, more recently, finite element (FE) methods provided no direct evidence for occlusal load distribution through the cortical and trabecular bone compartments individually. Therefore, we developed an improved three-dimensional FE model of the human skull in order to clarify the distribution of occlusal forces through the cortical and trabecular bone during habitual masticatory activities. Particular focus was placed on the load transfer through the anterior and posterior maxilla. The results were presented in von Mises stress (VMS) and the maximum principal stress, and compared to the reported FE and strain gauge data. Our qualitative stress analysis indicates that occlusal forces distribute through the mid-facial skeleton along five vertical and two horizontal buttresses. We demonstrated that cortical bone has a priority in the transfer of occlusal load in the anterior maxilla, whereas both cortical and trabecular bone in the posterior maxilla are equally involved in performing this task. Observed site dependence of the occlusal load distribution may help clinicians in creating strategies for implantology and orthodontic treatments. Additionally, the magnitude of VMS in our model was significantly lower in comparison to previous FE models composed only of cortical bone. This finding suggests that both cortical and trabecular bone should be modeled whenever stress will be quantitatively analyzed.

  20. Viral load: Roche applies for marketing approval for ultrasensitive test.

    PubMed

    1998-08-07

    Roche Molecular Systems has applied for FDA permission to market a more sensitive viral load test. The Amplicor HIV-1 Monitor UltraSensitive Method tests viral load as low as 50 copies; current tests are only accurate to 400 copies. There is a widespread consensus among physicians that testing below 400 copies would be a valuable treatment tool.

  1. Occlusion Calculator

    PubMed Central

    Hiremath, Anand; Aluckal, Eby

    2015-01-01

    Start with end in mind’ is a popular cliché in orthodontics. This aptly applies to the therapeutic occlusion the orthodontist strives to achieve. Predicting the post treatment occlusion is an essential component of treatment planning. When no extractions or symmetric extractions are done predicting the final occlusion is somewhat easy. Prediction is challenging when we do unconventional and/or asymmetric extractions. To aid this decision Kesling proposed the ‘Kesling Setup’. Though it serves the purpose acceptably; it is time, energy and money consuming. We have developed a model which can help us visualize the final occlusion in matter of seconds. Although this model is primarily intended for orthodontic postgraduate teaching, it can be of considerable use even to a seasoned orthodontist. The regular use of “Orthodontic Calculator” in our department is a testimony to its usefulness. PMID:25738101

  2. Stability of EB when cryostat load is applied.

    SciTech Connect

    Guarino, V. J.

    2004-09-03

    The cryostat load will be transferred to the EB with 24 modules in place. It is important to know that the EB is stable in this situation and during the subsequent assembly of the remaining modules. Appendix 1 describes a static 2D analysis that was done to examine the stability of the EB with the cryostat load applied. The paper below discussed the implications of this analysis.

  3. Buckling of circular cylindrical shells under dynamically applied axial loads

    NASA Technical Reports Server (NTRS)

    Tulk, J. D.

    1972-01-01

    A theoretical and experimental study was made of the buckling characteristics of perfect and imperfect circular cylindrical shells subjected to dynamic axial loading. Experimental data included dynamic buckling loads (124 data points), high speed photographs of buckling mode shapes and observations of the dynamic stability of shells subjected to rapidly applied sub-critical loads. A mathematical model was developed to describe the dynamic behavior of perfect and imperfect shells. This model was based on the Donnell-Von Karman compatibility and equilibrium equations and had a wall deflection function incorporating five separate modes of deflection. Close agreement between theory and experiment was found for both dynamic buckling strength and buckling mode shapes.

  4. Occlusal cranial balancing technique.

    PubMed

    Smith, Gerald H

    2007-01-01

    The acronym for Occlusal Cranial Balancing Technique is OCB. The OCB concept is based on the architectural principle of a level foundation. The principles of Occlusal Cranial Balancing are a monumental discovery and if applied will enhance total body function.

  5. Exercise, muscle, and the applied load-bone strength balance.

    PubMed

    Giangregorio, L; El-Kotob, R

    2017-01-01

    A fracture occurs when the applied load is greater than the bone can withstand. Clinical practice guidelines for the management of osteoporosis include recommendations for exercise; one of the few therapies where the proposed anti-fracture mechanisms that include effects on both bone strength and applied loads, where applied loads can come in the form of a fall, externally applied loads, body weight, or muscle forces. The aim of this review is to provide an overview of the clinical evidence pertaining to the potential efficacy of exercise for preventing fractures in older adults, including its direct effects on outcomes along the causal pathway to fractures (e.g., falls, posture, bone strength) and the indirect effects on muscle or the muscle-bone relationship. The evidence is examined as it pertains to application in clinical practice. Considerations for future research are discussed, such as the need for trials in individuals with low bone mass or students that evaluate whether changes in muscle mediate changes in bone. Future trials should also consider adequacy of calorie or protein intake, the confounding effect of exercise-induced weight loss, or the most appropriate therapeutic goal (e.g., strength, weight bearing, or hypertrophy) and outcome measures (e.g., fracture, disability, cost-effectiveness).

  6. Effects of Decreased Occlusal Loading during Growth on the Mandibular Bone Characteristics

    PubMed Central

    Hichijo, Natsuko; Tanaka, Eiji; Kawai, Nobuhiko; van Ruijven, Leo J.; Langenbach, Geerling E. J.

    2015-01-01

    Background Bone mass and mineralization are largely influenced by loading. The purpose of this study was to evaluate the reaction of the entire mandibular bone in response to decreased load during growth. It is hypothesized that decreased muscular loading will lead to bone changes as seen during disuse, i.e. loss of bone mass. Methods and Findings Ten 21-day-old Wistar strain male rats were divided into two groups (each n=5) and fed on either a hard- or soft-diet for 11 weeks. Micro-computed tomography was used for the investigation of bone mineralization, bone volume, bone volume fraction (BV/TV) and morphological analysis. Mandibular mineralization patterns were very consistent, showing a lower degree of mineralization in the ramus than in the corpus. In the soft-diet group, mineralization below the molars was significantly increased (p<0.05) compared to the hard diet group. Also, bone volume and BV/TV of the condyle and the masseter attachment were decreased in the soft-diet group (p<0.05). Morphological analysis showed inhibited growth of the ramus in the soft-diet group (p<0.05). Conclusion Decreased loading by a soft diet causes significant changes in the mandible. However, these changes are very region-specific, probably depending on the alterations in the local loading regime. The results suggest that muscle activity during growth is very important for bone quality and morphology. PMID:26062027

  7. In situ estimation of applied biaxial loads with Lamb waves.

    PubMed

    Shi, Fan; Michaels, Jennifer E; Lee, Sang Jun

    2013-02-01

    Spatially distributed arrays of piezoelectric disks are being applied to monitor structural integrity using Lamb waves. Applied loads directly affect waves propagating between array elements because of dimensional changes and the acoustoelastic effect. Resulting changes in phase velocity depend upon the propagation direction as well as the Lamb wave mode and frequency. This paper shows from numerical solutions of the acoustoelastic wave equation for an isotropic plate that it is possible to decouple the effects of a homogeneous biaxial stress into its two principal components. As a consequence of both this decoupling and material isotropy, the acoustoelastic response of a specific mode and frequency is described by only two constants, which can be determined from a uniaxial loading experiment. Using this formulation, a method is developed and verified via simulations to estimate an arbitrary biaxial load from phase velocity changes measured along multiple directions of propagation. Results from uniaxial loading experiments on two different plates further demonstrate the efficacy of the method. It is also shown that opening fatigue cracks may significantly degrade results by interfering with Lamb wave direct arrivals, but that this degradation can be mitigated by using a reduced set of data from unaffected paths of propagation.

  8. Immediate occlusal loading in edentulous jaws, CT-guided surgery and fixed provisional prosthesis: a maxillary arch clinical report.

    PubMed

    Drago, Carl; del Castillo, Robert; Peterson, Thomas

    2011-04-01

    Immediate occlusal loading (IOL) in edentulous jaws has been reported in numerous publications with implant cumulative survival rates consistent with conventional, unloaded healing protocols. Computed Tomography (CT)-guided surgery has more recently been developed and accepted as an additional treatment modality for maxillary and mandibular implant placement, with or without IOL. Reports as to the accuracy of planned versus actual implant placement in CT-guided surgeries have indicated that CT-guided surgery is not 100% accurate; standard deviations have been reported with values between 1 and 2 mm in terms of actual versus planned placement. The purpose of this article is to review the clinical parameters associated with IOL, and CT-guided surgery in edentulous jaws; and to present a clinical case illustrating the clinical and laboratory phases of treatment. The illustrated treatment was accomplished with an IOL protocol and includes fabrication and placement of a laboratory-processed provisional maxillary prosthesis. This particular protocol had slightly increased costs relative to conventional implant placement; however, the clinicians and patient benefited from improved accuracy of the provisional prostheses and decreased chairtime for the clinical procedures. The benefits and limitations of this treatment protocol are also discussed.

  9. An ultrasonic guided wave method to estimate applied biaxial loads

    NASA Astrophysics Data System (ADS)

    Shi, Fan; Michaels, Jennifer E.; Lee, Sang Jun

    2012-05-01

    Guided waves propagating in a homogeneous plate are known to be sensitive to both temperature changes and applied stress variations. Here we consider the inverse problem of recovering homogeneous biaxial stresses from measured changes in phase velocity at multiple propagation directions using a single mode at a specific frequency. Although there is no closed form solution relating phase velocity changes to applied stresses, prior results indicate that phase velocity changes can be closely approximated by a sinusoidal function with respect to angle of propagation. Here it is shown that all sinusoidal coefficients can be estimated from a single uniaxial loading experiment. The general biaxial inverse problem can thus be solved by fitting an appropriate sinusoid to measured phase velocity changes versus propagation angle, and relating the coefficients to the unknown stresses. The phase velocity data are obtained from direct arrivals between guided wave transducers whose direct paths of propagation are oriented at different angles. This method is applied and verified using sparse array data recorded during a fatigue test. The additional complication of the resulting fatigue cracks interfering with some of the direct arrivals is addressed via proper selection of transducer pairs. Results show that applied stresses can be successfully recovered from the measured changes in guided wave signals.

  10. An Experimental Study of Applied Ground Loads in Landing

    NASA Technical Reports Server (NTRS)

    Milwitzky, Benjamin; Lindquist, Dean C; Potter, Dexter M

    1955-01-01

    Results are presented of an experimental investigation made of the applied ground loads and the coefficient of friction between the tire and the ground during the wheel spin-up process in impacts of a small landing gear under controlled conditions on a concrete landing strip in the Langley impact basin. The basic investigation included three major phases: impacts with forward speed at horizontal velocities up to approximately 86 feet per second, impacts with forward speed and reverse wheel rotation to simulate horizontal velocities up to about 273 feet per second, and spin-up drop tests for comparison with the other tests. In addition to the basic investigation, supplementary tests were made to evaluate the drag-load alleviating effects of prerotating the wheel before impact so as to reduce the relative velocity between the tire and ground. In the presentation of the results, an attempt has been made to interpret the experimental data so as to obtain some insight into the physical phenomena involved in the wheel spin-up process.

  11. Applying modern measurements of Pleistocene loads to model lithospheric rheology

    NASA Astrophysics Data System (ADS)

    Beard, E. P.; Hoggan, J. R.; Lowry, A. R.

    2011-12-01

    The remnant shorelines of Pleistocene Lake Bonneville provide a unique opportunity for building a dataset from which to infer rheological properties of the lower crust and upper mantle. Multiple lakeshores developed over a period of around 30 kyr which record the lithosphere's isostatic response to a well-constrained load history. Bills et al. (1994) utilized a shoreline elevation dataset compiled by Currey (1982) in an attempt to model linear (Maxwell) viscosity as a function of depth beneath the basin. They estimated an effective elastic thickness (Te) for the basin of 20-25 km which differs significantly from the 5-15 km estimates derived from models of loading on geologic timescales (e.g., Lowry and Pérez-Gussinyé, 2011). We propose that the discrepancy in Te modeled by these two approaches may be resolved with dynamical modeling of a common rheology, using a more complete shoreline elevation dataset applied to a spherical Earth model. Where Currey's (1982) dataset was compiled largely from observations of depositional shoreline features, we are developing an algorithm for estimating elevation variations in erosional shorelines based on cross-correlation and stacking techniques similar to those used to automate picking of seismic phase arrival times. Application of this method to digital elevation models (DEMs) will increase the size and accuracy of the shoreline elevation dataset, enabling more robust modeling of the rheological properties driving isostatic response to unloading of Lake Bonneville. Our plan is to model these data and invert for a relatively small number of parameters describing depth- and temperature-dependent power-law rheology of the lower crust and upper mantle. These same parameters also will be used to model topographic and Moho response to estimates of regional mass variation on the longer loading timescales to test for inconsistencies. Bills, B.G., D.R. Currey, and G.A. Marshall, 1994, Viscosity estimates for the crust and upper

  12. Occlusion of carotid artery and hypergravity loading of animals caused similar effects on L-[14C]glutamate uptake in rat brain nerve terminals

    NASA Astrophysics Data System (ADS)

    Borisova, Tatiana; Sivko, Roman; Krisanova, Natalia

    Changes in sodium-dependent L-[14C]glutamate uptake in rat brain nerve terminals was com-paratively analysed after hypergravity loading of animals (centrifugation of rats in special con-tainers at 10 G for 1 hour) and unilateral occlusion of carotid artery (20 min). The initial velocity of L-[14C]glutamate uptake was decreased from 2.5 ± 0.2 nmol x min-1 x mg-1 of proteins to 2.05 ± 0.1 nmol x min-1 x mg-1 of proteins after hypergravity and after occlusion -up to 2.25 ± 0.1 nmol x min-1 x mg-1 of proteins. Recently, we have shown that a decrease in L-[14C]glutamate uptake was at least partially caused by the redaction in the membrane potential of nerve terminals and the proton gradient of synaptic vesicles. These parameters were analysed after unilateral occlusion of carotid artery, where one brain hemisphere was used as a control, whereas the second one as subjected to ischemic/hypoxic conditions. Similarly with hypergravity, we revealed a decrease in the membrane potential of nerve terminals by ˜ 10 % and a reduction of the proton gradient of synaptic vesicles by ˜ 5 % after occlusion of carotid artery. Thus, a decrease in the activity of glutamate transporters after hypergrav-ity and unilateral occlusion of carotid artery was at least partially caused by changes in the membrane potential of nerve terminals and the proton gradient of synaptic vesicles. This fact may be considered in support of the suggestion that ischemia/hypoxia was a main unspecific stressor, which caused the alterations in glutamatergic neurotransmission under conditions of hypergravity.

  13. Immediate Placement and Occlusal Loading of Single-Tooth Restorations on Partially Threaded, Titanium-Tantalum Combined Dental Implants: 1-Year Results.

    PubMed

    Peron, Cristian; Romanos, Georgios

    2016-01-01

    Single nonrestorable teeth were atraumatically extracted and hybrid titanium implants with tantalum-based midsections (TM) were placed in fresh extraction sockets. Provisional acrylic crowns were delivered (in occlusion) immediately after surgery. Occlusal contacts were present in the maximal intercuspation but not in the lateral movements of the mandible. Two weeks after placement, the implants were finally restored with screw-retained or cemented lithium disilicate crowns. A total of 25 patients were treated (26 implants). Most implants were placed in maxillary premolar locations and in lower-density bone. Mean crestal bone loss was 0.58 ± 0.34 mm. Implant survival and success rates were 100%, respectively (follow-up: 14.1 ± 1.5 months). Within the limitations of this study, immediate placement and loading of TM implants resulted in predictable clinical, functional, and esthetic outcomes.

  14. Determination of permissible applied load stress in structural elements

    NASA Technical Reports Server (NTRS)

    Loy, R. E.; Posever, F. C.

    1969-01-01

    Graphic method is used to select allowable stresses in thermally loaded structures. Equations are used for determining the mode of failure for specific materials in order to plot a range of stress curves. Linear assumption and iterative calculations are eliminated resulting in comparatively high accuracy.

  15. Effect of resin coating on adhesion and microleakage of computer-aided design/computer-aided manufacturing fabricated all-ceramic crowns after occlusal loading: a laboratory study.

    PubMed

    Kitayama, Shuzo; Pilecki, Peter; Nasser, Nasser A; Bravis, Theodora; Wilson, Ron F; Nikaido, Toru; Tagami, Junji; Watson, Timothy F; Foxton, Richard M

    2009-08-01

    This study investigated the effect of resin coating and occlusal loading on adhesion and microleakage of all-ceramic crowns. Molars were prepared for an all-ceramic crown and were divided into two groups: non-coated (control) and resin-coated with Clearfil Tri-S Bond. Crowns were fabricated using CEREC 3 and cemented using Clearfil Esthetic Cement. After 24 h of storage in water, the restored teeth in each group were divided into two subgroups: unloaded, or loaded while stored in water. Mechanical loading was achieved with an axial force of 80 N at 2.5 cycles s(-1) for 250,000 cycles. After immersion in Rhodamine B, the specimens were sectioned and processed for microleakage evaluation by confocal microscopy, which was followed by further sectioning for microtensile bond testing. Loading had no significant effect on microleakage in either the resin-coated or non-resin-coated groups. Resin coating did not reduce the microleakage at the dentine interface but increased the microleakage at the enamel interface. All the beams fractured during slicing when non-coated and loaded. The bond strengths of non-coated and unloaded, resin-coated and unloaded, and resin-coated and loaded groups were 15.82 +/- 4.22, 15.17 +/- 5.24, and 12.97 +/- 5.82 MPa, respectively. Resin coating with Clearfil Tri-S Bond improved the bonding of resin cement to dentine for loaded specimens. However, it was not effective in reducing the microleakage, regardless of whether it was loaded or unloaded.

  16. Temporomandibular disorders and occlusion.

    PubMed

    Badel, Tomislav; Marotti, Miljenko; Pavicin, Ivana Savić; Basić-Kes, Vanja

    2012-09-01

    Occlusion has an important place within the multifactorial concept of the temporomandibular disorder (TMD) etiopathogenesis as well as in every form of dental treatment. The modern concept of treatment of these disorders differentiates initial and definitive forms of treatment. The aim of this paper is to analyze recent viewpoints on the role of occlusion in the etiopathogenesis and treatment ofTMDs. Masticatory muscles and temporomandibular joints are directly connected with occlusal relations and TMDs are traditionally linked with occlusal disorders. The initial occlusal treatment can be applied to all TMD patients, regardless of their having intact teeth with respect to physiological occlusal relations and in patients in need of orthodontic or prosthodontic treatment or an oral surgical procedure. On managing TMD patients, there are doubts about the indications for definitive treatment and whether there has been a possibility of treating a painful TMD by reversible treatment modalities, that is, by initial treatment. Other types of orofacial pain such as trigeminal neuralgia can be comorbid with TMDs but also result in unnecessary procedures on the teeth and prosthodontic work if they are not recognized. Although dental profession mainly recognizes the importance of occlusal treatment of TMD problems, their relationship is controversial because it is not strictly demonstrated in numerous scientific studies. Occlusion is not the dominant cause of TMD problems.

  17. Control of bone remodelling by applied dynamic loads

    NASA Technical Reports Server (NTRS)

    Lanyon, L. E.; Rubin, C. T.

    1984-01-01

    The data showing the relationship between bone mass and peak strain magnitude prepared and submitted for publication. The data from experiments relating remodelling activity with static or dynamic loads were prepared and submitted for publication. Development of programs to relate the location of remodelling activity with he natural and artificial dynamic strain distributions continued. Experiments on the effect of different strain rates on the remodelling response continued.

  18. An Ultrasonic Guided Wave Method to Estimate Applied Biaxial Loads (Preprint)

    DTIC Science & Technology

    2011-11-01

    orientation are estimated from a sinusoidal fit of ultrasonic data collected from the same spatially distributed array that is being used to detect and...AFRL-RX-WP-TP-2011-4361 AN ULTRASONIC GUIDED WAVE METHOD TO ESTIMATE APPLIED BIAXIAL LOADS (PREPRINT) Fan, Shi, Jennifer E. Michaels, and...Technical Paper 1 November 2011 – 1 November 2011 4. TITLE AND SUBTITLE AN ULTRASONIC GUIDED WAVE METHOD TO ESTIMATE APPLIED BIAXIAL LOADS (PREPRINT

  19. Effect of different lateral occlusion schemes on peri-implant strain: A laboratory study

    PubMed Central

    Lo, Jennifer; Palamara, Joseph

    2017-01-01

    PURPOSE This study aims to investigate the effects of four different lateral occlusion schemes and different excursions on peri-implant strains of a maxillary canine implant. MATERIALS AND METHODS Four metal crowns with different occlusion schemes were attached to an implant in the maxillary canine region of a resin model. The included schemes were canine-guided (CG) occlusion, group function (GF) occlusion, long centric (LC) occlusion, and implant-protected (IP) occlusion. Each crown was loaded in three sites that correspond to maximal intercuspation (MI), 1 mm excursion, and 2 mm excursion. A load of 140 N was applied on each site and was repeated 10 times. The peri-implant strain was recorded by a rosette strain gauge that was attached on the resin model buccal to the implant. For each loading condition, the maximum shear strain value was calculated. RESULTS The different schemes and excursive positions had impact on the peri-implant strains. At MI and 1 mm positions, the GF had the least strains, followed by IP, CG, and LC. At 2 mm, the least strains were associated with GF, followed by CG, LC, and IP. However, regardless of the occlusion scheme, as the excursion increases, a linear increase of peri-implant strains was detected. CONCLUSION The peri-implant strain is susceptible to occlusal factors. The eccentric location appears to be more influential on peri-implant strains than the occlusion scheme. Therefore, adopting an occlusion scheme that can reduce the occurrence of occlusal contacts laterally may be beneficial in reducing peri-implant strains. PMID:28243391

  20. Using occlusal wear information and finite element analysis to investigate stress distributions in human molars.

    PubMed

    Benazzi, Stefano; Kullmer, Ottmar; Grosse, Ian R; Weber, Gerhard W

    2011-09-01

    Simulations based on finite element analysis (FEA) have attracted increasing interest in dentistry and dental anthropology for evaluating the stress and strain distribution in teeth under occlusal loading conditions. Nonetheless, FEA is usually applied without considering changes in contacts between antagonistic teeth during the occlusal power stroke. In this contribution we show how occlusal information can be used to investigate the stress distribution with 3D FEA in lower first molars (M(1)). The antagonistic crowns M(1) and P(2)-M(1) of two dried modern human skulls were scanned by μCT in maximum intercuspation (centric occlusion) contact. A virtual analysis of the occlusal power stroke between M(1) and P(2)-M(1) was carried out in the Occlusal Fingerprint Analyser (OFA) software, and the occlusal trajectory path was recorded, while contact areas per time-step were visualized and quantified. Stress distribution of the M(1) in selected occlusal stages were analyzed in strand7, considering occlusal information taken from OFA results for individual loading direction and loading area. Our FEA results show that the stress pattern changes considerably during the power stroke, suggesting that wear facets have a crucial influence on the distribution of stress on the whole tooth. Grooves and fissures on the occlusal surface are seen as critical locations, as tensile stresses are concentrated at these features. Properly accounting for the power stroke kinematics of occluding teeth results in quite different results (less tensile stresses in the crown) than usual loading scenarios based on parallel forces to the long axis of the tooth. This leads to the conclusion that functional studies considering kinematics of teeth are important to understand biomechanics and interpret morphological adaptation of teeth.

  1. Effect of applied load on the nondestructive measurement of concrete strength

    NASA Astrophysics Data System (ADS)

    Mahmoudabadi, E.; Amjad, U.; Kundu, T.; Saadatmanesh, H.

    2014-03-01

    Nondestructive measurement of the concrete strength is an important topic of research. Among different nondestructive testing (NDT) methods the ultrasonic pulse velocity (UPV) technique is the most popular method for concrete strength estimation. While measuring concrete strength by this method almost all researchers have neglected the effect of applied stress or load on the concrete member. In this investigation attempts were made to properly incorporate the effect of the applied load on the strength prediction of concrete specimens from UPV value. To achieve this goal, 4 groups of concrete specimens with different values of final strength were made. Materials used for making cylindrical specimens of 3 inch diameter and 6 inch height included regular Portland cement, water and two types of aggregate - fine and coarse. After applying the load on the specimen in multiple steps - up to 70% of its failure strength fc'- the time of flight (TOF) value was measured for every loading step. The recorded results showed that applied load on the member has significant effect on the measured UPV value on concrete specimens. Therefore, to find the strength of the concrete from the UPV value, the applied load on the sample should be considered as an important factor that cannot be neglected.

  2. Elastic-Plastic Strain Acceptance Criteria for Structures Subject to Rapidly Applied Transient Dynamic Loading

    SciTech Connect

    W.R. Solonick

    2003-04-01

    Rapidly applied transient dynamic loads produce stresses and deflections in structures that typically exceed those from static loading conditions. Previous acceptance criteria for structures designed for rapidly applied transient dynamic loading limited stresses to those determined from elastic analysis. Different stress limits were established for different grades of structure depending upon the amount of permanent set considered acceptable. Structure allowed to sustain very limited permanent set is designed to stress limits not significantly greater than yield stress. Greater permanent set in structure under rapidly applied transient dynamic loading conditions is permitted by establishing stress limits that are significantly greater than yield stress but still provide adequate safety margin (with respect to failure). This paper presents a strain-based elastic-plastic (i.e., inelastic) analysis criterion developed as an alternative to the more conservative stress-based elastic analysis stress criterion for structures subjected to rapidly applied transient dynamic loading. The strain limits established are based on material ductility considerations only and are set as a fraction of the strain at ultimate stress obtained from an engineering stress/strain curve of the material. Strains limits are categorized by type as membrane or surface and by region as general, local , or concentrated. The application of the elastic-plastic criterion provides a more accurate, less conservative design/analysis basis for structures than that used in elastic stress-based analysis criteria, while still providing adequate safety margins.

  3. Elastic-plastic strain acceptance criterion for structures subject to rapidly applied transient dynamic loading

    SciTech Connect

    Solonick, W.

    1996-11-01

    Rapidly applied transient dynamic loads produce stresses and deflections in structures that typically exceed those from static loading conditions. Previous acceptance criteria for structures designed for rapidly applied transient dynamic loading limited stresses to those determined from elastic analysis. Different stress limits were established for different grades of structure depending upon the amount of permanent set considered acceptable. Structure allowed to sustain very limited permanent set is designed to stress limits not significantly greater than yield stress. Greater permanent set in structure under rapidly applied transient dynamic loading conditions is permitted by establishing stress limits that are significantly greater than yield stress but still provide adequate safety margin (with respect to failure). This paper presents a strain-based elastic-plastic (i.e., inelastic) analysis criterion developed as an alternative to the more conservative stress-based elastic analysis stress criterion for structures subjected to rapidly applied transient dynamic loading. The strain limits established are based on a fraction of the strain at ultimate stress obtained from an engineering stress/strain curve of the material. Strains limits are categorized by type as membrane or surface and by region as general, local, or concentrated. The application of the elastic-plastic criterion provides a more accurate, less conservative design/analysis basis for structures than that used in elastic stress-based analysis criteria, while still providing adequate safety margins.

  4. The rat lumbosacral spinal cord adapts to robotic loading applied during stance.

    PubMed

    Timoszyk, W K; De Leon, R D; London, N; Roy, R R; Edgerton, V R; Reinkensmeyer, D J

    2002-12-01

    Load-related afferent information modifies the magnitude and timing of hindlimb muscle activity during stepping in decerebrate animals and spinal cord-injured humans and animals, suggesting that the spinal cord mediates load-related locomotor responses. In this study, we found that stepping on a treadmill by adult rats that received complete, midthoracic spinal cord transections as neonates could be altered by loading the hindlimbs using a pair of small robotic arms. The robotic arms applied a downward force to the lower shanks of the hindlimbs during the stance phase and measured the position of the lower shank during stepping. No external force was applied during the swing phase of the step. When applied bilaterally, this stance force field perturbed the hindlimb trajectories so that the ankle position was shifted downward during stance. In response to this perturbation, both the stance and step cycle durations decreased. During swing, the hindlimb initially accelerated toward the normal, unperturbed swing trajectory and then tracked the normal trajectory. Bilateral loading increased the magnitude of the medial gastrocnemius electromyographic (EMG) burst during stance and increased the amplitude of the semitendinosus and rectus femoris EMG bursts. When the force field was applied unilaterally, stance duration decreased in the loaded hindlimb, while swing duration was decreased in the contralateral hindlimb, thereby preserving interlimb coordination. These results demonstrate the feasibility of using robotic devices to mechanically modulate afferent input to the injured spinal cord during weight-supported locomotion. In addition, these results indicate that the lumbosacral spinal cord responds to load-related input applied to the lower shank during stance by modifying step timing and muscle activation patterns, while preserving normal swing kinematics and interlimb coordination.

  5. Vertical accelerator device to apply loads simulating blast environments in the military to human surrogates.

    PubMed

    Yoganandan, Narayan; Pintar, Frank A; Schlick, Michael; Humm, John R; Voo, Liming; Merkle, Andrew; Kleinberger, Michael

    2015-09-18

    The objective of the study was to develop a simple device, Vertical accelerator (Vertac), to apply vertical impact loads to Post Mortem Human Subject (PMHS) or dummy surrogates because injuries sustained in military conflicts are associated with this vector; example, under-body blasts from explosive devices/events. The two-part mechanically controlled device consisted of load-application and load-receiving sections connected by a lever arm. The former section incorporated a falling weight to impact one end of the lever arm inducing a reaction at the other/load-receiving end. The "launch-plate" on this end of the arm applied the vertical impact load/acceleration pulse under different initial conditions to biological/physical surrogates, attached to second section. It is possible to induce different acceleration pulses by using varying energy absorbing materials and controlling drop height and weight. The second section of Vertac had the flexibility to accommodate different body regions for vertical loading experiments. The device is simple and inexpensive. It has the ability to control pulses and flexibility to accommodate different sub-systems/components of human surrogates. It has the capability to incorporate preloads and military personal protective equipment (e.g., combat helmet). It can simulate vehicle roofs. The device allows for intermittent specimen evaluations (x-ray and palpation, without changing specimen alignment). The two free but interconnected sections can be used to advance safety to military personnel. Examples demonstrating feasibilities of the Vertac device to apply vertical impact accelerations using PMHS head-neck preparations with helmet and booted Hybrid III dummy lower leg preparations under in-contact and launch-type impact experiments are presented.

  6. Tank Applied Testing of Load-Bearing Multilayer Insulation (LB-MLI)

    NASA Technical Reports Server (NTRS)

    Johnson, Wesley L.; Valenzuela, Juan G.; Feller, Jerr; Plachta, Dave

    2014-01-01

    The development of long duration orbital cryogenic storage systems will require the reduction of heat loads into the storage tank. In the case of liquid hydrogen, complete elimination of the heat load at 20 K is currently impractical due to the limitations in lift available on flight cryocoolers. In order to reduce the heat load, without having to remove heat at 20 K, the concept of Reduced Boil-Off uses cooled shields within the insulation system at approximately 90 K. The development of Load-Bearing Multilayer Insulation (LB-MLI) allowed the 90 K shield with tubing and cryocooler attachments to be suspended within the MLI and still be structurally stable. Coupon testing both thermally and structurally were performed to verify that the LB-MLI should work at the tank applied level. Then tank applied thermal and structural (acoustic) testing was performed to demonstrate the functionality of the LB-MLI as a structural insulation system. The LB-MLI showed no degradation of thermal performance due to the acoustic testing and showed excellent thermal performance when integrated with a 90 K class cryocooler on a liquid hydrogen tank.

  7. Tank Applied Testing of Load-Bearing Multilayer Insulation (LB-MLI)

    NASA Technical Reports Server (NTRS)

    Johnson, Wesley L.; Valenzuela, Juan G.; Feller, Jeffrey R.; Plachta, David W.

    2014-01-01

    The development of long duration orbital cryogenic storage systems will require the reduction of heat loads into the storage tank. In the case of liquid hydrogen, complete elimination of the heat load at 20 K is currently impractical due to the limitations in lift available on flight cryocoolers. In order to reduce the heat load, without having to remove heat at 20 K, the concept of Reduced Boil-Off uses cooled shields within the insulation system at approximately 90 K. The development of Load-Bearing Multilayer Insulation (LB-MLI) allowed the 90 K shield with tubing and cryocooler attachments to be suspended within the MLI and still be structurally stable. Coupon testing, both thermal and structural was performed to verify that the LB-MLI should work at the tank applied level. Then tank applied thermal and structural (acoustic) testing was performed to demonstrate the functionality of the LB-MLI as a structural insulation system. The LB-MLI showed no degradation of thermal performance due to the acoustic testing and showed excellent thermal performance when integrated with a 90 K class cryocooler on a liquid hydrogen tank.

  8. Effects of Applied Load on 6061-T6 Aluminum Joined Employing a Novel Friction Bonding Process

    SciTech Connect

    Douglas E. Burkes; Neil P. Hallinan; Karen L. Shropshire; Peter B. Wells

    2008-12-01

    Friction bonding is under consideration for use in mass production of plate-type nuclear fuels for research reactors. This article discusses the effects of applied load (the most important process parameter for fabrication of these fuels) on temperature distribution, microstructure, and mechanical properties. Friction bonding experiments showed that tool geometry caused temperature gradients across the tool surface. Temperatures at the joint interface suggested the advancing side of the tool produced a majority of the frictional heat, while the retreating side of the tool mainly forged the plasticized material while bonding increased with applied load. The microstructure across the tool surface was also altered and, as a function of applied load, affected the mechanical properties. The 6061 aluminum alloy had mechanical properties close to a T4 temper after processing. Results documented in this article will aid in continual enhancement of friction bonding for nuclear fuel plate fabrication, and will hopefully contribute to continued advancement of friction stir welding (FSW) state of the art.

  9. Formation of metalsbnd F bonds during frictional sliding: Influence of water and applied load

    NASA Astrophysics Data System (ADS)

    Shen, J. T.; Pei, Y. T.; De Hosson, J. Th. M.

    2016-04-01

    Effects of water lubrication and applied load on the formation of PTFE transfer films and metalsbnd F bonds during sliding when PTFE filled composites sliding against steel and Al2O3 are investigated. In water-lubricated conditions, XPS analysis reveals that a thin layer of water molecules at the sliding interface inhibits the formation of PTFE transfer films and Alsbnd F bonds on the Al2O3 ball, leading to a detrimental effect on the tribo-performance. Under various normal loads in dry sliding condition, it is found that the smearing of PTFE onto the wear surface of the composite and the transfer of PTFE onto the surface of the steel counterpart are stimulated by a high load. During sliding, the contact pressure is found to be the driving force of the reaction between steel and PTFE. It is concluded that under various loads, the total amount of PTFE transfer films has a larger impact on the friction behavior than the formation of Fesbnd F bonds.

  10. On the relationship between matched filter theory as applied to gust loads and phased design loads analysis

    NASA Technical Reports Server (NTRS)

    Zeiler, Thomas A.; Pototzky, Anthony S.

    1989-01-01

    A theoretical basis and example calculations are given that demonstrate the relationship between the Matched Filter Theory approach to the calculation of time-correlated gust loads and Phased Design Load Analysis in common use in the aerospace industry. The relationship depends upon the duality between Matched Filter Theory and Random Process Theory and upon the fact that Random Process Theory is used in Phased Design Loads Analysis in determining an equiprobable loads design ellipse. Extensive background information describing the relevant points of Phased Design Loads Analysis, calculating time-correlated gust loads with Matched Filter Theory, and the duality between Matched Filter Theory and Random Process Theory is given. It is then shown that the time histories of two time-correlated gust load responses, determined using the Matched Filter Theory approach, can be plotted as parametric functions of time and that the resulting plot, when superposed upon the design ellipse corresponding to the two loads, is tangent to the ellipse. The question is raised of whether or not it is possible for a parametric load plot to extend outside the associated design ellipse. If it is possible, then the use of the equiprobable loads design ellipse will not be a conservative design practice in some circumstances.

  11. Occlusion in implant dentistry. A review of the literature of prosthetic determinants and current concepts.

    PubMed

    Gross, M D

    2008-06-01

    Today the clinician is faced with widely varying concepts regarding the number, location, distribution and inclination of implants required to support the functional and parafunctional demands of occlusal loading. Primary clinical dilemmas of planning for maximal or minimal numbers of implants, their axial inclination, lengths and required volume and quality of supporting bone remain largely unanswered by adequate clinical outcome research. Planning and executing optimal occlusion schemes is an integral part of implant supported restorations. In its wider sense this includes considerations of multiple inter-relating factors of ensuring adequate bone support, implant location number, length, distribution and inclination, splinting, vertical dimension aesthetics, static and dynamic occlusal schemes and more. Current concepts and research on occlusal loading and overloading are reviewed together with clinical outcome and biomechanical studies and their clinical relevance discussed. A comparison between teeth and implants regarding their proprioceptive properties and mechanisms of supporting functional and parafunctional loading is made and clinical applications made regarding current concepts in restoring the partially edentulous dentition. The relevance of occlusal traumatism and fatigue microdamage alone or in combination with periodontal or peri-implant inflammation is reviewed and applied to clinical considerations regarding splinting of adjacent implants and teeth, posterior support and eccentric guidance schemes. Occlusal restoration of the natural dentition has classically been divided into considerations of planning for sufficient posterior support, occlusal vertical dimension and eccentric guidance to provide comfort and aesthetics. Mutual protection and anterior disclusion have come to be considered as acceptable therapeutic modalities. These concepts have been transferred to the restoration of implant-supported restoration largely by default. However, in

  12. Phase-shifting real-time holographic interferometry applied to load transmission evaluation in dried human skull.

    PubMed

    Gesualdi, Marcos R R; Mori, Matsuyoshi; Muramatsu, Mikiya; Liberti, Edson A; Munin, Egberto

    2007-08-01

    Phase-shifting real-time holography with photorefractive Bi(12)SiO(20) crystal as holographic recording medium applied to load transmission evaluation and tension dissipation on a dried human skull under loading is presented. The applied loading stands as a simulation of isolated contraction (SIC) of some masticatories muscles. The four-frames phase-shifting technique and the unwrapping branch-cut technique were used to obtain the phase map. The quantitative results show the feasibility of the employed system in the study of microdisplacements in the skull structure provided by SIC.

  13. Lingualized occlusion. An occlusion for all reasons.

    PubMed

    Parr, G R; Ivanhoe, J R

    1996-01-01

    This authors make practical recommendations for a wide variety of clinical situations, including various anteroposterior and buccolingual arch discrepancies. Many of the ideals of the anatomical and mechanical schools of thought are blended. In addition to being a valuable clinical adjunct, Lingualized Occlusion also has great application in undergraduate dental education. It is a simpler occlusal scheme to teach and learn.

  14. Occlusion: an orthodontic perspective.

    PubMed

    Kasrovi, P M; Meyer, M; Nelson, G D

    2000-10-01

    In recent years, orthodontists have examined their concepts of occlusion. In current literature, at professional meetings, and in continuing education courses, one hears an ongoing discussion of condylar position and mandibular border movements in relation to occlusion. There is a wide variation in opinion as to whether dental occlusion and TMJ function are interdependent. The authors have adopted a dynamic concept of dental function to replace the traditional static view of molar relationship and incisor overlap. This article discusses how occlusion has evolved in orthodontics and reviews Andrews' six keys to ideal static occlusion, the goals of ideal dynamic occlusion, and the six signs of developing malocclusions. The authors also review the literature on the relationship between orthodontics, occlusion, and TMD.

  15. Non Linear Effects of Applied Loads and Large Deformations on Aircraft Normal Modes

    DTIC Science & Technology

    2000-05-01

    the sBams secteo lia base for the solution of many structural dynamics and static dermations. aeroelastic problems (flutter, response to gust and 0...manufacturing and certification of the Horizontal Tailplanes (HTP). In the case of a megaliner, the Figure 1. Beam with static axial load and dynamic...method. The effect of in-plane loading is considered large static deformations. in two parts. First, effects of direct in-plane loading only Most of the

  16. Does increasing applied load lead to contact changes indicative of knee osteoarthritis? A subject-specific FEA study.

    PubMed

    Boyd, Jennifer L; Zavatsky, Amy B; Gill, Harinderjit S

    2016-04-01

    This study investigated whether increased loading (representing obesity) in the extended knee and flexed knee led to increased stresses in areas of typical medial and lateral osteoarthritis cartilage lesions, respectively. We created two paired sets of subject-specific finite element models; both sets included models of extended knees and of flexed knees. The first set represented normal loading; the second set represented increased loading. All other variables were held constant. The von Mises stresses and contact areas calculated on the tibial cartilage surfaces of the paired models were then compared. In the extended knee models, applying a larger load led to increased stress in the anterior and central regions of the medial tibial cartilage. These are the typical locations of medial osteoarthritis cartilage lesions. Therefore, the results support that increased loading in the extended knee may result in medial osteoarthritis. In the flexed knee models, applying a larger load increased stress in the anterior and central regions of the lateral tibial cartilage. Lateral osteoarthritis cartilage lesions typically occur centrally and posteriorly. Therefore, these results do not support our hypothesis. Shear stress was increased in areas of typical lateral lesions, however, and should be investigated in future studies.

  17. Controversies in occlusion.

    PubMed

    Chasens, A I

    1990-01-01

    The tissues and structures of the stomatognathic system adapt in different ways but in a coordinated manner to functional forces. This adaptive capacity differs from individual to individual and tends to cloud the picture as to how these mechanisms function. This leads to many areas of disagreement as to the role of occlusal trauma in the etiology of periodontal disease; the importance of centric, bite collapse versus arch collapse; the role of incisal guidance in maintaining occlusal stability; canine protected-guided occlusion versus group function; the use of appliances in occlusal therapy; prophylactic versus interceptive occlusal adjustment; and the role of bruxism and other parafunctional habits in occlusal trauma. An attempt is made in this article to clarify these issues.

  18. Finite element analysis to characterize how varying patellar loading influences pressure applied to cartilage: model evaluation.

    PubMed

    Shah, Kushal S; Saranathan, Archana; Koya, Bharath; Elias, John J

    2015-01-01

    A finite element analysis (FEA) modeling technique has been developed to characterize how varying the orientation of the patellar tendon influences the patellofemoral pressure distribution. To evaluate the accuracy of the technique, models were created from MRI images to represent five knees that were previously tested in vitro to determine the influence of hamstrings loading on patellofemoral contact pressures. Hamstrings loading increased the lateral and posterior orientation of the patellar tendon. Each model was loaded at 40°, 60°, and 80° of flexion with quadriceps force vectors representing the experimental loading conditions. The orientation of the patellar tendon was represented for the loaded and unloaded hamstrings conditions based on experimental measures of tibiofemoral alignment. Similar to the experimental data, simulated loading of the hamstrings within the FEA models shifted the center of pressure laterally and increased the maximum lateral pressure. Significant (p < 0.05) differences were identified for the center of pressure and maximum lateral pressure from paired t-tests carried out at the individual flexion angles. The ability to replicate experimental trends indicates that the FEA models can be used for future studies focused on determining how variations in the orientation of the patellar tendon related to anatomical or loading variations or surgical procedures influence the patellofemoral pressure distribution.

  19. Follicular occlusion tetrad

    PubMed Central

    Vasanth, Vani; Chandrashekar, Byalakere Shivanna

    2014-01-01

    Follicular occlusion tetrad is a symptom complex consisting of four conditions having a similar pathophysiology. It includes Hidradenitis suppurativa, acne conglobata, dissecting cellulitis of the scalp and pilonidal sinus. The exact pathogenesis of this group of disease is unknown but evidence suggests that they share the same pathological process initiated by follicular occlusion in apocrine gland bearing areas. Though each of these conditions is commonly encountered singly, follicular occlusion tetrad as a symptom complex has been rarely reported in the literature. PMID:25396138

  20. Occlusion and facial pain.

    PubMed

    Klineberg, I

    1978-02-01

    The role of the occlusion in the aetiology of reflex jaw muscle hyperactivity and myofacial pain is analysed. Neurological mechanisms are proposed to explain how variations in occlusal morphology of sufficient magnitude (segmental influences), and the presence of anxiety states (suprasegmental influences) affect jaw muscle activity and contribute to myofascial pain. Controlled occlusal therapy may alter the segmental neurological control of jaw muscle activity to facilitate resolution of muscle hyperactivity in acute myofascial pain. Chronic myofascial pain dysfunction is not primarily related to occlusal factors and a complex psychophysiological mechanism is involved in this type of pain problem.

  1. The cost of chronic stress in childhood: understanding and applying the concept of allostatic load.

    PubMed

    Katz, Debra A; Sprang, Ginny; Cooke, Circe

    2012-09-01

    This article explores the concept of allostatic load and its utility as an integrative framework for thinking about the impact of chronic stress on children and adolescents. Allostatic load refers to the failure or exhaustion of normal physiologic processes that occurs in response to severe, frequent, or chronic stressors. This persistent physiologic dysregulation may lead to secondary health problems such as immunosuppression, obesity, atherosclerosis, and hypertension. Allostatic load can be measured and followed as a composite index of a group of physiologic parameters which fall outside of a normal range. Although research regarding allostatic load in children is limited, this article explores relevant studies and identifies ways in which the concept of allostatic load can be used to broaden approaches to assessment, case formulation, and treatment in children. The concept of allostatic load may be of particular interest to psychodynamic psychiatrists in recognizing the ways in which chronic stress and adverse childhood experiences lead not only to negative psychological sequelae but also to long-term health consequences including the possibility of premature death. It underscores the importance of monitoring patients' physical as well as psychological health and thinking about the complex interrelations between the two.

  2. Thermomechanical loading applied on the cladding tube during the pellet cladding mechanical interaction phase of a rapid reactivity initiated accident

    NASA Astrophysics Data System (ADS)

    Hellouin de Menibus, Arthur; Sercombe, Jerome; Auzoux, Quentin; Poussard, Christophe

    2014-10-01

    Calculations of the CABRI REP-Na5 pulse were performed with the ALCYONE code in order to determine the evolution of the thermomechanical loading applied on the cladding tube during the Pellet-Cladding Mechanical Interaction (PCMI) phase of a rapid Reactivity Initiated Accident (RIA) initiated at 280 °C that lasted 8.8 ms. The evolution of the following parameters are reported: the cladding temperature, heating rate, strain rate and loading biaxiality. The impact of these parameters on the cladding mechanical behavior and fracture are then briefly reviewed.

  3. The Reusable Load Cell with Protection Applied for Online Monitoring of Overhead Transmission Lines Based on Fiber Bragg Grating

    PubMed Central

    Ma, Guoming; Mao, Naiqiang; Li, Yabo; Jiang, Jun; Zhou, Hongyang; Li, Chengrong

    2016-01-01

    Heavy ice coating of high–voltage overhead transmission lines may lead to conductor breakage and tower collapse causing the unexpected interrupt of power supply. The optical load cell applied in ice monitoring systems is immune to electromagnetic interference and has no need of a power supply on site. Therefore, it has become a hot research topic in China and other countries. In this paper, to solve the problem of eccentric load in measurement, we adopt the shearing structure with additional grooves to improve the strain distribution and acquire good repeatability. Then, the fiber Bragg grating (FBG) with a permanent weldable package are mounted onto the front/rear groove of the elastic element by spot welding, the direction deviation of FBGs is 90° from each other to achieve temperature compensation without an extra FBG. After that, protection parts are designed to guarantee high sensitivity for a light load condition and industrial safety under a heavy load up to 65 kN. The results of tension experiments indicate that the sensitivity and resolution of the load cell is 0.1285 pm/N and 7.782 N in the conventional measuring range (0–10 kN). Heavy load tension experiments prove that the protection structure works and the sensitivity and resolution are not changed after several high load (65 kN) cycles. In addition, the experiment shows that the resolution of the sensor is 87.79 N in the large load range, allowing the parameter to be used in heavy icing monitoring. PMID:27338403

  4. The Reusable Load Cell with Protection Applied for Online Monitoring of Overhead Transmission Lines Based on Fiber Bragg Grating.

    PubMed

    Ma, Guoming; Mao, Naiqiang; Li, Yabo; Jiang, Jun; Zhou, Hongyang; Li, Chengrong

    2016-06-21

    Heavy ice coating of high-voltage overhead transmission lines may lead to conductor breakage and tower collapse causing the unexpected interrupt of power supply. The optical load cell applied in ice monitoring systems is immune to electromagnetic interference and has no need of a power supply on site. Therefore, it has become a hot research topic in China and other countries. In this paper, to solve the problem of eccentric load in measurement, we adopt the shearing structure with additional grooves to improve the strain distribution and acquire good repeatability. Then, the fiber Bragg grating (FBG) with a permanent weldable package are mounted onto the front/rear groove of the elastic element by spot welding, the direction deviation of FBGs is 90° from each other to achieve temperature compensation without an extra FBG. After that, protection parts are designed to guarantee high sensitivity for a light load condition and industrial safety under a heavy load up to 65 kN. The results of tension experiments indicate that the sensitivity and resolution of the load cell is 0.1285 pm/N and 7.782 N in the conventional measuring range (0-10 kN). Heavy load tension experiments prove that the protection structure works and the sensitivity and resolution are not changed after several high load (65 kN) cycles. In addition, the experiment shows that the resolution of the sensor is 87.79 N in the large load range, allowing the parameter to be used in heavy icing monitoring.

  5. The occlusal guard: a simplified technique for fabrication and equilibration.

    PubMed

    Antonelli, John; Hottel, Timothy L; Siegel, Sharon C; Brandt, Robert; Silva, Gladston

    2013-01-01

    Hard occlusal guards have been used effectively to treat myofacial pain originating from parafunctional activities. Also, they can protect the natural dentition when it opposes porcelain restorations, help to evaluate changes in occlusal vertical dimension during full mouth rehabilitation, minimize further tooth loss in patients with abfraction lesions, and redirect occlusal loads more favorably onto dental implant-supported prostheses. A simplified technique is described to fabricate a properly designed wax model of an occlusal guard that can be processed in acrylic in the same manner used to construct a complete denture.

  6. Runoff and phosphorus loads from two Iowa fields with and without applied manure, 2000-2011

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Understanding the dynamics of field-edge runoff water quality and responses to changes in management practices and climate through monitoring will probably require decade-duration data sets. This study compared runoff volumes and phosphorus loads from two fields in central Iowa, where the glacial la...

  7. Applying Cognitive Load Theory to the Redesign of a Conventional Database Systems Course

    ERIC Educational Resources Information Center

    Mason, Raina; Seton, Carolyn; Cooper, Graham

    2016-01-01

    Cognitive load theory (CLT) was used to redesign a Database Systems course for Information Technology students. The redesign was intended to address poor student performance and low satisfaction, and to provide a more relevant foundation in database design and use for subsequent studies and industry. The original course followed the conventional…

  8. A comparative analysis of restorative materials used in abfraction lesions in tooth with and without occlusal restoration: Three-dimensional finite element analysis

    PubMed Central

    Srirekha, A; Bashetty, Kusum

    2013-01-01

    Objectives: The present comparative analysis aimed at evaluating the mechanical behavior of various restorative materials in abfraction lesion in the presence and absence of occlusal restoration. Materials and Methods: A three-dimensional finite-element analysis was performed. Six experimental models of mandibular first premolar were generated and divided into two groups (groups A and B) of three each. All the groups had cervical abfraction lesion restored with materials and in addition group A had class I occlusal restoration. A load of 90 N, 200 N, and 400 N were applied at 45° loading angle on the buccal inclines of buccal cusp and Von Mises stresses was chosen for analysis. Results: In all the models, the values of stress recorded at the cervical margin of the restorations were at their maxima. Irrespective of the occlusal restoration, all the materials performed well at 90 N and 200 N. At 400 N, only low-shrink composite showed stresses lesser than its tensile strength indicating its success even at higher load. Conclusion: Irrespective of occlusal restoration, restorative materials with low modulus of elasticity are successful in abfraction lesions at moderate tensile stresses; whereas materials with higher modulus of elasticity and mechanical properties can support higher loads and resist wear. Significance: The model allows comparison of different restorative materials for restoration of abfraction lesions in the presence and absence of occlusal restoration. The model can be used to validate more sophisticated computational models as well as to conduct various optimization studies. PMID:23716970

  9. Numerical simulation on the biomechanical interactions of tooth/implant-supported system under various occlusal forces with rigid/non-rigid connections.

    PubMed

    Lin, Chun-Li; Wang, Jen-Chyan; Kuo, Yu-Chan

    2006-01-01

    The aim of this study was to analyze the biomechanics in an implant/tooth-supported system under different occlusal forces with rigid/non-rigid connectors by adopting a 3D non-linear finite element (FE) approach. A 3D FE model containing one Frialit-2 implant splinted to the mandibular second premolar was constructed. Contact elements (frictional surface) were used to simulate the realistic interface condition within the implant system and the sliding keyway stress-breaker function. The stress distributions in the splinting system and dissimilar mobility between natural tooth and implant with rigid and non-rigid connectors were observed for six loading types. The simulated results indicated that the lateral occlusal forces significantly increased the implant (sigma(I, max)), alveolar bone (sigma(AB, max)) and prosthesis (sigma(P, max)) stress values when compared with the axial occlusal forces. The sigma(I, max) and sigma(AB, max) values did not exhibit significant differences regardless of the connector type used. However, the sigma(P, max) values with a non-rigid connection increased more than two times those of the rigid connection. The sigma(I, max), sigma(AB, max) and sigma(P, max) stress values were significantly reduced in centric or lateral contact situations once the occlusal forces on the pontic were decreased. Moreover, the vertical-tooth-to-implant displacement ratios with a non-rigid connection were 23 and 9.9 times that for axial and lateral loads, respectively, applied on the premolar. However, the compensated non-rigid connector capabilities were not significant when occlusal forces acted on the complete prosthesis. The non-rigid connector (keyway device) only significantly exploited its function when the occlusal forces acted on a natural tooth. Minimizing the occlusal loading force on the pontic area through occlusal adjustment procedures to redistribute stress in the maximum intercuspation or lateral working position for an implant

  10. Optimizing physicians' instruction of PACS through e-learning: cognitive load theory applied.

    PubMed

    Devolder, P; Pynoo, B; Voet, T; Adang, L; Vercruysse, J; Duyck, P

    2009-03-01

    This article outlines the strategy used by our hospital to maximize the knowledge transfer to referring physicians on using a picture archiving and communication system (PACS). We developed an e-learning platform underpinned by the cognitive load theory (CLT) so that in depth knowledge of PACS' abilities becomes attainable regardless of the user's prior experience with computers. The application of the techniques proposed by CLT optimizes the learning of the new actions necessary to obtain and manipulate radiological images. The application of cognitive load reducing techniques is explained with several examples. We discuss the need to safeguard the physicians' main mental processes to keep the patient's interests in focus. A holistic adoption of CLT techniques both in teaching and in configuration of information systems could be adopted to attain this goal. An overview of the advantages of this instruction method is given both on the individual and organizational level.

  11. Structural Load Alleviation Applied to Next Generation Aircraft and Wind Turbines

    NASA Technical Reports Server (NTRS)

    Frost, Susan

    2011-01-01

    Reducing the environmental impact of aviation is a goal of the Subsonic Fixed Wing Project under the Fundamental Aeronautics Program of NASAs Aeronautics Research Mission Directorate. Environmental impact of aviation is being addressed by novel aircraft configurations and materials that reduce aircraft weight and increase aerodynamic efficiency. NASA is developing tools to address the challenges of increased airframe flexibility created by wings constructed with reduced structural material and novel light-weight materials. This talk will present a framework and demonstration of a flight control system using optimal control allocation with structural load feedback and constraints to achieve safe aircraft operation. As wind turbines age, they become susceptible to many forms of blade degradation. Results will be presented on work in progress that uses adaptive contingency control for load mitigation in a wind turbine simulation with blade damage progression modeled.

  12. In Situ Estimation of Applied Biaxial Loads with Lamb Waves (Preprint)

    DTIC Science & Technology

    2012-07-01

    axis. Approved for public release; distribution unlimited. Load estimation with Lamb waves Page 6 Gandhi et al. [19] have developed theory to...Using software developed by Gandhi [20], dispersion curves for different propagating angles are plotted in Fig. 2(a) over a narrow frequency range for...phase velocity with respect to propagation angle for this same mode and a frequency of 400 kHz. As noted by Gandhi [20], it can be seen that there is a

  13. Code to Optimize Load Sharing of Split-Torque Transmissions Applied to the Comanche Helicopter

    NASA Technical Reports Server (NTRS)

    1995-01-01

    Most helicopters now in service have a transmission with a planetary design. Studies have shown that some helicopters would be lighter and more reliable if they had a transmission with a split-torque design instead. However, a split-torque design has never been used by a U.S. helicopter manufacturer because there has been no proven method to ensure equal sharing of the load among the multiple load paths. The Sikorsky/Boeing team has chosen to use a split-torque transmission for the U.S. Army's Comanche helicopter, and Sikorsky Aircraft is designing and manufacturing the transmission. To help reduce the technical risk of fielding this helicopter, NASA and the Army have done the research jointly in cooperation with Sikorsky Aircraft. A theory was developed that equal load sharing could be achieved by proper configuration of the geartrain, and a computer code was completed in-house at the NASA Lewis Research Center to calculate this optimal configuration.

  14. Experimental characterization and constitutive modeling of the mechanical behavior of molybdenum under electromagnetically applied compression-shear ramp loading

    DOE PAGES

    Alexander, C. Scott; Ding, Jow -Lian; Asay, James Russell

    2016-03-09

    Magnetically applied pressure-shear (MAPS) is a new experimental technique that provides a platform for direct measurement of material strength at extreme pressures. The technique employs an imposed quasi-static magnetic field and a pulsed power generator that produces an intense current on a planar driver panel, which in turn generates high amplitude magnetically induced longitudinal compression and transverse shear waves into a planar sample mounted on the drive panel. In order to apply sufficiently high shear traction to the test sample, a high strength material must be used for the drive panel. Molybdenum is a potential driver material for the MAPSmore » experiment because of its high yield strength and sufficient electrical conductivity. To properly interpret the results and gain useful information from the experiments, it is critical to have a good understanding and a predictive capability of the mechanical response of the driver. In this work, the inelastic behavior of molybdenum under uniaxial compression and biaxial compression-shear ramp loading conditions is experimentally characterized. It is observed that an imposed uniaxial magnetic field ramped to approximately 10 T through a period of approximately 2500 μs and held near the peak for about 250 μs before being tested appears to anneal the molybdenum panel. In order to provide a physical basis for model development, a general theoretical framework that incorporates electromagnetic loading and the coupling between the imposed field and the inelasticity of molybdenum was developed. Based on this framework, a multi-axial continuum model for molybdenum under electromagnetic loading is presented. The model reasonably captures all of the material characteristics displayed by the experimental data obtained from various experimental configurations. Additionally, data generated from shear loading provide invaluable information not only for validating but also for guiding the development of the material

  15. Experimental characterization and constitutive modeling of the mechanical behavior of molybdenum under electromagnetically applied compression-shear ramp loading

    SciTech Connect

    Alexander, C. Scott; Ding, Jow -Lian; Asay, James Russell

    2016-03-09

    Magnetically applied pressure-shear (MAPS) is a new experimental technique that provides a platform for direct measurement of material strength at extreme pressures. The technique employs an imposed quasi-static magnetic field and a pulsed power generator that produces an intense current on a planar driver panel, which in turn generates high amplitude magnetically induced longitudinal compression and transverse shear waves into a planar sample mounted on the drive panel. In order to apply sufficiently high shear traction to the test sample, a high strength material must be used for the drive panel. Molybdenum is a potential driver material for the MAPS experiment because of its high yield strength and sufficient electrical conductivity. To properly interpret the results and gain useful information from the experiments, it is critical to have a good understanding and a predictive capability of the mechanical response of the driver. In this work, the inelastic behavior of molybdenum under uniaxial compression and biaxial compression-shear ramp loading conditions is experimentally characterized. It is observed that an imposed uniaxial magnetic field ramped to approximately 10 T through a period of approximately 2500 μs and held near the peak for about 250 μs before being tested appears to anneal the molybdenum panel. In order to provide a physical basis for model development, a general theoretical framework that incorporates electromagnetic loading and the coupling between the imposed field and the inelasticity of molybdenum was developed. Based on this framework, a multi-axial continuum model for molybdenum under electromagnetic loading is presented. The model reasonably captures all of the material characteristics displayed by the experimental data obtained from various experimental configurations. Additionally, data generated from shear loading provide invaluable information not only for validating but also for guiding the development of the material model for

  16. Experimental characterization and constitutive modeling of the mechanical behavior of molybdenum under electromagnetically applied compression-shear ramp loading

    NASA Astrophysics Data System (ADS)

    Alexander, C. S.; Ding, J. L.; Asay, J. R.

    2016-03-01

    Magnetically applied pressure-shear (MAPS) is a new experimental technique that provides a platform for direct measurement of material strength at extreme pressures. The technique employs an imposed quasi-static magnetic field and a pulsed power generator that produces an intense current on a planar driver panel, which in turn generates high amplitude magnetically induced longitudinal compression and transverse shear waves into a planar sample mounted on the drive panel. In order to apply sufficiently high shear traction to the test sample, a high strength material must be used for the drive panel. Molybdenum is a potential driver material for the MAPS experiment because of its high yield strength and sufficient electrical conductivity. To properly interpret the results and gain useful information from the experiments, it is critical to have a good understanding and a predictive capability of the mechanical response of the driver. In this work, the inelastic behavior of molybdenum under uniaxial compression and biaxial compression-shear ramp loading conditions is experimentally characterized. It is observed that an imposed uniaxial magnetic field ramped to approximately 10 T through a period of approximately 2500 μs and held near the peak for about 250 μs before being tested appears to anneal the molybdenum panel. In order to provide a physical basis for model development, a general theoretical framework that incorporates electromagnetic loading and the coupling between the imposed field and the inelasticity of molybdenum was developed. Based on this framework, a multi-axial continuum model for molybdenum under electromagnetic loading is presented. The model reasonably captures all of the material characteristics displayed by the experimental data obtained from various experimental configurations. In addition, data generated from shear loading provide invaluable information not only for validating but also for guiding the development of the material model for

  17. Healing efficiency of shape memory polyurethane fiber reinforced syntactic foam under applied load

    NASA Astrophysics Data System (ADS)

    Ogunmekan, Babatunde

    Shape memory composite materials have received a great deal of interest in recent structural developments, both in sandwich and in lightweight structures. Experimental procedures involving the free body healing of these materials have been carried out; however, it is important to investigate the healing behaviors of these SMP materials while under load. In this study, syntactic foams reinforced with strain-hardened short-shape memory polyurethane fibers (SMPUFs) were prepared to evaluate their ability to heal wide-opened cracks using the two-step biomimetic close-then-heal (CTH) self-healing scheme while under varying loads. The syntactic foam samples manufactured consisted of an epoxy matrix with dispersed thermoplastic particles, glass microballoons and short SMPUFs. The SMPUF strands were cold-drawn (stretched-then-released) for up to four cycles and then cut to 10 mm short fibers before casting the polymer matrix. Three types of syntactic foam specimens, consisting of 5%, 10%, and 15% thermoplastic particle volume fraction compositions, respectively, were manufactured, and notched beam samples were then prepared. Fracture-healing by uniaxial tension was conducted for five cycles on each sample. Material characterization techniques, such as scanning electron microscopy (SEM) and differential scanning calorimetry (DSC), were utilized to highlight the crack healing characteristics and thermal properties. In addition, a high-resolution charge-coupled device (CCD) camera with a resolution of 3.7 x 3.7 μm/pixel was used to capture the crack tip opening displacement (CTOD). It is seen that the healing ability of the composite varies with changes in both the load carried and the volume fraction of thermoplastic particles. As the thermoplastic volume fraction increased from 5% to 10% to 15%, the tensile strength values recorded decreased, but there was also an increase in the healing efficiency. Moreover, SEM images revealed partial healing in samples with lower

  18. Nonlinear Loading-Rate-Dependent Force Response of Individual Vimentin Intermediate Filaments to Applied Strain

    NASA Astrophysics Data System (ADS)

    Block, Johanna; Witt, Hannes; Candelli, Andrea; Peterman, Erwin J. G.; Wuite, Gijs J. L.; Janshoff, Andreas; Köster, Sarah

    2017-01-01

    The mechanical properties of eukaryotic cells are to a great extent determined by the cytoskeleton, a composite network of different filamentous proteins. Among these, intermediate filaments (IFs) are exceptional in their molecular architecture and mechanical properties. Here we directly record stress-strain curves of individual vimentin IFs using optical traps and atomic force microscopy. We find a strong loading rate dependence of the mechanical response, supporting the hypothesis that IFs could serve to protect eukaryotic cells from fast, large deformations. Our experimental results show different unfolding regimes, which we can quantitatively reproduce by an elastically coupled system of multiple two-state elements.

  19. Acute arterial occlusion - kidney

    MedlinePlus

    Acute renal arterial thrombosis; Renal artery embolism; Acute renal artery occlusion; Embolism - renal artery ... kidneys need a good blood supply. The main artery to the kidney is called the renal artery. ...

  20. Model of the hydrodynamic loads applied on a rotating halfbridge belonging to a circular settling tank

    NASA Astrophysics Data System (ADS)

    Dascalescu, A. E.; Lazaroiu, G.; Scupi, A. A.; Oanta, E.

    2016-08-01

    The rotating half-bridge of a settling tank is employed to sweep the sludge from the wastewater and to vacuum and sent it to the central collector. It has a complex geometry but the main beam may be considered a slender bar loaded by the following category of forces: concentrated forces produced by the weight of the scrapping system of blades, suction pipes, local sludge collecting chamber, plus the sludge in the horizontal sludge transporting pipes; forces produced by the access bridge; buoyant forces produced by the floating barrels according to Archimedes’ principle; distributed forces produced by the weight of the main bridge; hydrodynamic forces. In order to evaluate the hydrodynamic loads we have conceived a numerical model based on the finite volume method, using the ANSYS-Fluent software. To model the flow we used the equations of Reynolds Averaged Navier-Stokes (RANS) for liquids together with Volume of Fluid model (VOF) for multiphase flows. For turbulent model k-epsilon we used the equation for turbulent kinetic energy k and dissipation epsilon. These results will be used to increase the accuracy of the loads’ sub-model in the theoretical models, e. the finite element model and the analytical model.

  1. Pin Load Control Applied to Retractable Pin Tool Technology and Its Characterization

    NASA Technical Reports Server (NTRS)

    Olegoetz, P.

    1999-01-01

    Until the development of retractable pin tool (RPT) technology, friction stir welding (FSW) was limited to constant thickness joining of aluminum materials and the choices of keyhole elimination focused on traditional fusion and plug weld repair techniques. An invention, US Patent Number 5,893,507, "Auto-Adjustable Pin Tool for Friction Stir Welding" assigned to NASA, demonstrated an approach to resolve these serious drawbacks. This approach brings forth a technique that allows the crater, or keyhole, to be closed out automatically at the end of the weld joint without adding any additional equipment or material. Also the probe length can be varied automatically in the weld joint to compensate for material thickness changes, such as, in a tapered joint. This paper reports the effects of pin extension and retraction rates in the weld joint and its correlation to weld quality. The investigation utilized a pin load-detecting device that was integrated in the Phase IIA RPT designed by Boeing for NASA/MSFC. The RPT modification provided pin load data that was accessed and used to eliminate root side indications and determine pin manipulation rates necessary to produce consistence homogeneous joints.

  2. Pin Load Control Applied to Retractable Pin Tool Technology and its Characterization

    NASA Technical Reports Server (NTRS)

    Oelgoetz, Peter

    2000-01-01

    Until the development of retractable pin tool (RPT) technology, friction stir welding (FSW) was limited to constant thickness joining of aluminum materials and the choices of keyhole elimination focused on traditional fusion and plug weld repair techniques. An invention, US Patent Number 5,893.507, "Auto-Adjustable Pin Tool for Friction Stir Welding" assigned to NASA, demonstrated an approach to resolve these serious drawbacks. This approach brings forth a technique that allows the crater, or keyhole, to be closed out automatically at the end of the weld joint without adding any additional equipment or material. Also the probe length can be varied automatically in the weld joint to compensate for material thickness changes, such as, in a tapered joint. This paper reports the effects of pin extension and retraction rates in the weld joint and its correlation to weld quality. The investigation utilized a pin load-detecting device that was integrated in the Phase 2A RPT designed by Boeing for NASA/MSFC. The RPT modification provided pin load data that was accessed and used to eliminate root side indications and determine pin manipulation rates necessary to produce consistence homogeneous joints.

  3. Pin Load Control Applied to Retractable Pin Tool Technology and its Characterization

    NASA Technical Reports Server (NTRS)

    Oelgoetz, Peter A.

    2000-01-01

    Until the development of retractable pin tool (RPT) technology, friction stir welding (FSW) was limited to constant thickness joining of aluminum materials and the choices of keyhole elimination focused on traditional fusion and plug weld repair techniques. An invention, US Patent Number 5,893,507, "Auto-Adjustable Pin Tool for Friction Stir Welding" assigned to NASA, demonstrated an approach to resolve these serious drawbacks. This approach brings forth a technique that allows the crater, or keyhole, to be closed out automatically at the end of the weld joint without adding any additional equipment or material. Also the probe length can be varied automatically in the weld joint to compensate for material thickness changes, such as, in a tapered joint. This paper reports the effects of pin extension and retraction rates in the weld joint and its correlation to weld quality. The investigation utilized a pin load-detecting device that was integrated in the Phase 2A RPT designed by Boeing for NASA/MSFC. The RPT modification provided pin load data that was accessed and used to eliminate root side indications and determine pin manipulation rates necessary to produce consistence homogeneous joints.

  4. Applying Model-based Diagnosis to a Rapid Propellant Loading System

    NASA Technical Reports Server (NTRS)

    Goodrich, Charlie H.; Narasimhan, Sriram; Daigle, Matthew J.; Hatfield, Walter H.; Johnson, Robert G.

    2009-01-01

    The overall objective of the US Air Force Research Laboratory (AFRL) Rapid Propellant Loading (RPL) Program is to develop a launch vehicle, payload and ground support equipment that can support a rapid propellant load and launch within one hour. NASA Kennedy Space Center (KSC) has been funded by AFRL to develop hardware and software to demonstrate this capability. The key features of the software would be the ability to recognize and adapt to failures in the physical hardware components, advise operators of equipment faults and workarounds, and put the system in a safe configuration if unable to fly. In December 2008 NASA KSC and NASA Ames Research Center (ARC) demonstrated model based simulation and diagnosis capabilities for a scaled-down configuration of the RPL hardware. In this paper we present a description of the model-based technologies that were included as part of this demonstration and the results that were achieved. In continuation of this work we are currently testing the technologies on a simulation of the complete RPL system. Later in the year, when the RPL hardware is ready, we will be integrating these technologies with the real-time operation of the system to provide live state estimates. In future years we will be developing the capability to recover from faulty conditions via redundancy and reconfiguration.

  5. Disk-loaded RF waveguide matching techniques applied to silicon woodpile accelerator

    SciTech Connect

    Wu Ziran; England, Joel; Ng, Cho; Tantawi, Sami

    2012-12-21

    Silicon woodpile photonic crystal provides a three-dimensional dielectric waveguide system for high-gradient laser driven acceleration. The woodpile waveguide is periodically loaded in the longitudinal direction; therefore simple cross-sectional mode profile matching is not sufficient to launch the accelerating mode appropriately and will result in significant scattering loss. Hinted by the common nature of longitudinal periodicity between disk-loaded waveguide and woodpile waveguide, several coupler design schemes developed for multi-cell RF cavity are implemented in the woodpile accelerator design. Among them there are the travelling-wave match method based on S-matrix, the periodic VSWR method, and the TE-to-TM coupling iris design. This paper presents design procedures and simulation results using these methods. According to simulations, nearly 100% power transmission between SOI and woodpile waveguides with a travelling-wave match is achieved with a specially designed mode-launching coupler. Constructed by silicon rods extruding into the defect waveguide, the coupling iris provides necessary transition from TE mode to TM accelerating mode, also with negligible coupling loss.

  6. Study for the Effect of Continuously Applied Load on a Compressed Ag Nanoparticle at Room Temperature by Atomic Scale Simulations

    NASA Astrophysics Data System (ADS)

    Zhang, Lin

    2016-05-01

    Molecular dynamics calculations are reported for structural transition of a compressed Ag nanoparticle containing 2123 atoms with a crystal structure during the processes of continuously applied load at room temperature. Analytical tools are used to demonstrate the effect of the load on the packing patterns in this deformed particle including internal energy per atom, pair distribution functions, coordination number, pair number as well as the cross-sectional images, and mean square displacements. The simulation results show that the deformation processes of this particle include different stages. Owing to the atom sliding in the (111) plane in different regions of this particle, some interfaces are formed between these regions, and they are barriers of atom movements. With increasing the load, the interfaces in the middle of this particle are disappeared, and the deformation is able to carry out. At larger load, new interfaces are formed in the different regions of this heavily compressed particle with several atom layers, and these interfaces again become obstacles for the further deformation.

  7. Removable partial denture occlusion.

    PubMed

    Ivanhoe, John R; Plummer, Kevin D

    2004-07-01

    No single occlusal morphology, scheme, or material will successfully treat all patients. Many patients have been treated, both successfully and unsuccessfully, using widely varying theories of occlusion, choices of posterior tooth form, and restorative materials. Therefore, experience has demonstrated that there is no one righ r way to restore the occlusion of all patients. Partially edentulous patients have many and varied needs. Clinicians must understand the healthy physiologic gnathostomatic system and properly diagnose what is or may become pathologic. Henderson [3] stated that the occlusion of the successfully treated patient allows the masticating mechanism to carry out its physiologic functions while the temporomandibular joints, the neuromuscular mechanism, the teeth and their supporting structures remain in a good state of health. Skills in diagnosis and treatment planning are of utmost importance in treating these patients, for whom the clinician's goals are not only an esthetic and functional restoration but also a lasting harmonious state. Perhaps this was best state by DeVan [55] more than 60 years ago in his often-quoted objective. "The patient's fundamental need is the continued meticulous restoration of what is missing, since what is lost is in a sense irretrievably lost." Because it is clear that there is no one method, no one occlusal scheme, or one material that guarantees success for all patients, recommendations for consideration when establishing or reestablishing occlusal schemes have been presented. These recommendations must be used in conjunction with other diagnostic and technical skills.

  8. A multi-phase Equation of State diagnostic applied to the study of shock loaded tin

    NASA Astrophysics Data System (ADS)

    Shenton-Taylor, Caroline; Glauser, Antony; Ota, Thomas; Price, Ed

    2011-06-01

    The accurate detection of shock driven material phase transitions demands a multiple diagnostic capable of simultaneously measuring temperature, emissivity, pressure and velocity. By combining optical pyrometry with reflectivity based emissivity diagnostics we report shock loaded tin temperatures from 820 K to 1780 K with associated probable errors down to +/- 12.8 K. In addition simultaneous Class 4 laser heterodyne velocimetry recorded the tin surface velocity as viewed through a LiF anvil. Constraining the tin pressure with lithium fluoride generated microsecond experiment time durations; thermal diffusion models identified the tin/glue/LiF layer as advantageous for temperature measurement. Across a range of pressures, the emissivity corrected temperature data were found to be well aligned with a single tin Equation of State model. AWE Crown Owned Copyright (2011).

  9. [Occlusal contact principles in prosthodontics].

    PubMed

    Wang, Meiqing

    2012-12-01

    The occlusion contact, which is engaged in many dental clinical scopes, is the primary subject in the field of dental occlusion. Prosthodontics is one of the fields that are involved in with this subject, including the static relation (the occlusal contacts in intercuspal occlusion) and the dynamic relation (such as that in chewing movement). Not only the restorations, but also the abutments, that have to be properly managed to obtain a harmony occlusal contact relationship.

  10. Quantitative Microbial Risk Assessment Tutorial: Land-applied Microbial Loadings within a 12-Digit HUC

    EPA Science Inventory

    This tutorial reviews screens, icons, and basic functions of the SDMProjectBuilder (SDMPB). It demonstrates how one chooses a 12-digit HUC for analysis, performs an assessment of land-applied microbes by simulating microbial fate and transport using HSPF, and analyzes and visuali...

  11. Occlusal considerations in implant therapy: clinical guidelines with biomechanical rationale.

    PubMed

    Kim, Yongsik; Oh, Tae-Ju; Misch, Carl E; Wang, Hom-Lay

    2005-02-01

    Due to lack of the periodontal ligament, osseointegrated implants, unlike natural teeth, react biomechanically in a different fashion to occlusal force. It is therefore believed that dental implants may be more prone to occlusal overloading, which is often regarded as one of the potential causes for peri-implant bone loss and failure of the implant/implant prosthesis. Overloading factors that may negatively influence on implant longevity include large cantilevers, parafunctions, improper occlusal designs, and premature contacts. Hence, it is important to control implant occlusion within physiologic limit and thus provide optimal implant load to ensure a long-term implant success. The purposes of this paper are to discuss the importance of implant occlusion for implant longevity and to provide clinical guidelines of optimal implant occlusion and possible solutions managing complications related to implant occlusion. It must be emphasized that currently there is no evidence-based, implant-specific concept of occlusion. Future studies in this area are needed to clarify the relationship between occlusion and implant success.

  12. Lower Arm Muscle Activation during Indirect-Localized Vibration: The Influence of Skill Levels When Applying Different Acceleration Loads

    PubMed Central

    Padulo, Johnny; Di Giminiani, Riccardo; Dello Iacono, Antonio; Zagatto, Alessandro M.; Migliaccio, Gian M.; Grgantov, Zoran; Ardigò, Luca P.

    2016-01-01

    We investigated the electromyographic response to synchronous indirect-localized vibration interventions in international and national table tennis players. Twenty-six male table tennis players, in a standing position, underwent firstly an upper arms maximal voluntary contraction and thereafter two different 30-s vibration interventions in random order: high acceleration load (peak acceleration = 12.8 g, frequency = 40 Hz; peak-to-peak displacement = 4.0 mm), and low acceleration load (peak acceleration = 7.2 g, frequency = 30 Hz, peak-to-peak displacement = 4.0 mm). Surface electromyography root mean square from brachioradialis, extensor digitorum, flexor carpi radialis, and flexor digitorum superficialis recorded during the two vibration interventions was normalized to the maximal voluntary contraction recording. Normalized surface electromyography root mean square was higher in international table tennis players with respect to national ones in all the interactions between muscles and vibration conditions (P < 0.05), with the exception of flexor carpi radialis (at low acceleration load, P > 0.05). The difference in normalized surface electromyography root mean square between international table tennis players and national ones increased in all the muscles with high acceleration load (P < 0.05), with the exception of flexor digitorum superficialis (P > 0.05). The muscle activation during indirect-localized vibration seems to be both skill level and muscle dependent. These results can optimize the training intervention in table tennis players when applying indirect-localized vibration to lower arm muscles. Future investigations should discriminate between middle- and long-term adaptations in response to specific vibration loads. PMID:27378948

  13. Study of the strength of molybdenum under high pressure using electromagnetically applied compression-shear ramp loading

    NASA Astrophysics Data System (ADS)

    Ding, Jow; Alexander, C. Scott; Asay, James

    2015-06-01

    MAPS (Magnetically Applied Pressure Shear) is a new technique that has the potential to study material strength under mega-bar pressures. By applying a mixed-mode pressure-shear loading and measuring the resultant material responses, the technique provides explicit and direct information on material strength under high pressure. In order to apply sufficient shear traction to the test sample, the driver must have substantial strength. Molybdenum was selected for this reason along with its good electrical conductivity. In this work, the mechanical behavior of molybdenum under MAPS loading was studied. To understand the experimental data, a viscoplasticity model with tension-compression asymmetry was also developed. Through a combination of experimental characterization, model development, and numerical simulation, many unique insights were gained on the inelastic behavior of molybdenum such as the effects of strength on the interplay between longitudinal and shear stresses, potential interaction between the magnetic field and molybdenum strength, and the possible tension-compression asymmetry of the inelastic material response. Sandia National Labs is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corp., for the U.S. Dept. of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000.

  14. Effect of cell and microvillus mechanics on the transmission of applied loads to single bonds in dynamic force spectroscopy

    NASA Astrophysics Data System (ADS)

    Gupta, V. K.; Eggleton, C. D.

    2011-07-01

    Receptor-ligand interactions that mediate cellular adhesion are often subjected to forces that regulate their detachment via modulating off-rates. Although the dynamics of detachment is primarily controlled by the physical chemistry of adhesion molecules, cellular features such as cell deformability and microvillus viscoelasticity have been shown to affect the rolling velocity of leukocytes in vitro through experiments and simulation. In this work, we demonstrate via various micromechanical models of two cells adhered by a single (intramolecular) bond that cell deformability and microvillus viscoelasticity modulate transmission of an applied external load to an intramolecular bond, and thus the dynamics of detachment. Specifically, it is demonstrated that the intermolecular bond force is not equivalent to the instantaneous applied force and that the instantaneous bond force decreases with cellular and microvillus compliance. As cellular compliance increases, not only does the time lag between the applied load and the bond force increase, an initial response time is observed during which cell deformation is observed without transfer of force to the bond. It is further demonstrated that following tether formation the instantaneous intramoleular bond force increases linearly at a rate dependent on microvillus viscosity. Monte Carlo simulations with fixed kinetic parameters predict that both cell and microvillus compliance increase the average rupture time, although the average rupture force based on bond length remains nearly unchanged.

  15. Observation of multipactor suppression in a dielectric-loaded accelerating structure using an applied axial magnetic field

    SciTech Connect

    Jing, C.; Konecny, R.; Antipov, S.; Chang, C.; Gold, S. H.; Schoessow, P.; Kanareykin, A.; Gai, W.

    2013-11-18

    Efforts by a number of institutions to develop a Dielectric-Loaded Accelerating (DLA) structure capable of supporting high gradient acceleration when driven by an external radio frequency source have been ongoing over the past decade. Single surface resonant multipactor has been previously identified as one of the major limitations on the practical application of DLA structures in electron accelerators. In this paper, we report the results of an experiment that demonstrated suppression of multipactor growth in an X-band DLA structure through the use of an applied axial magnetic field. This represents an advance toward the practical use of DLA structures in many accelerator applications.

  16. Original analytical model of the hydrodynamic loads applied on the half-bridge of a circular settling tank

    NASA Astrophysics Data System (ADS)

    Oanta, Emil M.; Dascalescu, Anca-Elena; Sabau, Adrian

    2016-12-01

    The paper presents an original analytical model of the hydrodynamic loads applied on the half-bridge of a circular settling tank. The calculus domain is defined using analytical geometry and the calculus of the local dynamic pressure is based on the radius from the center of the settling tank to the current area, i.e. the relative velocity of the fluid and the depth where the current area is located, i.e. the density of the fluid. Calculus of the local drag forces uses the discrete frontal cross sectional areas of the submerged structure in contact with the fluid. In the last stage is performed the reduction of the local drag forces in the appropriate points belonging to the main beam. This class of loads is producing the flexure of the main beam in a horizontal plane and additional twisting moments along this structure. Taking into account the hydrodynamic loads, the results of the theoretical models, i.e. the analytical model and the finite element model, may have an increased accuracy.

  17. Applied and engineering versions of the theory of elastoplastic processes of active complex loading part 2: Identification and verification

    NASA Astrophysics Data System (ADS)

    Peleshko, V. A.

    2016-06-01

    The deviator constitutive relation of the proposed theory of plasticity has a three-term form (the stress, stress rate, and strain rate vectors formed from the deviators are collinear) and, in the specialized (applied) version, in addition to the simple loading function, contains four dimensionless constants of the material determined from experiments along a two-link strain trajectory with an orthogonal break. The proposed simple mechanism is used to calculate the constants of themodel for four metallic materials that significantly differ in the composition and in the mechanical properties; the obtained constants do not deviate much from their average values (over the four materials). The latter are taken as universal constants in the engineering version of the model, which thus requires only one basic experiment, i. e., a simple loading test. If the material exhibits the strengthening property in cyclic circular deformation, then the model contains an additional constant determined from the experiment along a strain trajectory of this type. (In the engineering version of the model, the cyclic strengthening effect is not taken into account, which imposes a certain upper bound on the difference between the length of the strain trajectory arc and the module of the strain vector.) We present the results of model verification using the experimental data available in the literature about the combined loading along two- and multi-link strain trajectories with various lengths of links and angles of breaks, with plane curvilinear segments of various constant and variable curvature, and with three-dimensional helical segments of various curvature and twist. (All in all, we use more than 80 strain programs; the materials are low- andmedium-carbon steels, brass, and stainless steel.) These results prove that the model can be used to describe the process of arbitrary active (in the sense of nonnegative capacity of the shear) combine loading and final unloading of originally

  18. Progression of Diabetic Capillary Occlusion: A Model

    PubMed Central

    Gens, John Scott; Glazier, James A.; Burns, Stephen A.; Gast, Thomas J.

    2016-01-01

    An explanatory computational model is developed of the contiguous areas of retinal capillary loss which play a large role in diabetic maculapathy and diabetic retinal neovascularization. Strictly random leukocyte mediated capillary occlusion cannot explain the occurrence of large contiguous areas of retinal ischemia. Therefore occlusion of an individual capillary must increase the probability of occlusion of surrounding capillaries. A retinal perifoveal vascular sector as well as a peripheral retinal capillary network and a deleted hexagonal capillary network are modelled using Compucell3D. The perifoveal modelling produces a pattern of spreading capillary loss with associated macular edema. In the peripheral network, spreading ischemia results from the progressive loss of the ladder capillaries which connect peripheral arterioles and venules. System blood flow was elevated in the macular model before a later reduction in flow in cases with progression of capillary occlusions. Simulations differing only in initial vascular network structures but with identical dynamics for oxygen, growth factors and vascular occlusions, replicate key clinical observations of ischemia and macular edema in the posterior pole and ischemia in the retinal periphery. The simulation results also seem consistent with quantitative data on macular blood flow and qualitative data on venous oxygenation. One computational model applied to distinct capillary networks in different retinal regions yielded results comparable to clinical observations in those regions. PMID:27300722

  19. Accuracy of 3-D reconstruction with occlusions.

    PubMed

    Begon, Mickaël; Lacouture, Patrick

    2010-02-01

    A marker has to be seen by at least two cameras for its three-dimensional (3-D) reconstruction, and the accuracy can be improved with more cameras. However, a change in the set of cameras used in the reconstruction can alter the kinematics. The purpose of this study was to quantify the harmful effect of occlusions on two-dimensional (2-D) images and to make recommendations about the signal processing. A reference kinematics data set was collected for a three degree-of-freedom linkage with three cameras of a commercial motion analysis system without any occlusion on the 2-D images. In the 2-D images, some occlusions were artificially created based on trials of real cyclic motions. An interpolation of 2-D trajectories before the 3-D reconstruction and two filters (Savitsky-Golay and Butterworth filters) after reconstruction were successively applied to minimize the effect of the 2-D occlusions. The filter parameters were optimized by minimizing the root mean square error between the reference and the filtered data. The optimal parameters of the filters were marker dependent, whereas no filter was necessary after a 2-D interpolation. As the occlusions cause systematic error in the 3-D reconstruction, the interpolation of the 2-D trajectories is more appropriate than filtering the 3-D trajectories.

  20. An enhanced drought-tolerant method using SA-loaded PAMPS polymer materials applied on tobacco pelleted seeds.

    PubMed

    Guan, Yajing; Cui, Huawei; Ma, Wenguang; Zheng, Yunye; Tian, Yixin; Hu, Jin

    2014-01-01

    Drought is one of the most important stress factors limiting the seed industry and crop production. Present study was undertaken to create novel drought-resistant pelleted seeds using the combined materials with superabsorbent polymer, poly(2-acrylamide-2-methyl propane sulfonic acid) (PAMPS) hydrogel, and drought resistance agent, salicylic acid (SA). The optimized PAMPS hydrogel was obtained as the molar ratio of 2-acrylamido-2-methyl-propanesulfonic acid (AMPS) to potassium peroxydisulfate (KPS) and N, N'-methylene-bis-acrylamide (MBA) was 1 : 0.00046 : 0.00134. The hydrogel weight after swelling in deionized water for 24 h reached 4306 times its own dry weight. The water retention ratio (RR) of PAMPS was significantly higher as compared with the control. It could keep as high as 85.3% of original weight after 30 min at 110 °C; even at 25 °C for 40 d, the PAMPS still kept RR at 33.67%. PAMPS disintegration ratio increased gradually and reached around 30% after embedding in soil or activated sludge for 60 d. In addition, there were better seed germination performance and seedling growth in the pelleted treatments with SA-loaded PAMPS hydrogel under drought stress than control. It suggested that SA-loaded PAMPS hydrogel, a nontoxic superabsorbent polymer, could be used as an effective drought resistance material applied to tobacco pelleted seeds.

  1. An Enhanced Drought-Tolerant Method Using SA-Loaded PAMPS Polymer Materials Applied on Tobacco Pelleted Seeds

    PubMed Central

    Guan, Yajing; Cui, Huawei; Ma, Wenguang; Zheng, Yunye; Tian, Yixin; Hu, Jin

    2014-01-01

    Drought is one of the most important stress factors limiting the seed industry and crop production. Present study was undertaken to create novel drought-resistant pelleted seeds using the combined materials with superabsorbent polymer, poly(2-acrylamide-2-methyl propane sulfonic acid) (PAMPS) hydrogel, and drought resistance agent, salicylic acid (SA). The optimized PAMPS hydrogel was obtained as the molar ratio of 2-acrylamido-2-methyl-propanesulfonic acid (AMPS) to potassium peroxydisulfate (KPS) and N, N′-methylene-bis-acrylamide (MBA) was 1 : 0.00046 : 0.00134. The hydrogel weight after swelling in deionized water for 24 h reached 4306 times its own dry weight. The water retention ratio (RR) of PAMPS was significantly higher as compared with the control. It could keep as high as 85.3% of original weight after 30 min at 110°C; even at 25°C for 40 d, the PAMPS still kept RR at 33.67%. PAMPS disintegration ratio increased gradually and reached around 30% after embedding in soil or activated sludge for 60 d. In addition, there were better seed germination performance and seedling growth in the pelleted treatments with SA-loaded PAMPS hydrogel under drought stress than control. It suggested that SA-loaded PAMPS hydrogel, a nontoxic superabsorbent polymer, could be used as an effective drought resistance material applied to tobacco pelleted seeds. PMID:25250387

  2. A new crank arm-based load cell for the 3D analysis of the force applied by a cyclist.

    PubMed

    Balbinot, Alexandre; Milani, Cleiton; Nascimento, Jussan da Silva Bahia

    2014-12-03

    This report describes a new crank arm-based force platform designed to evaluate the three-dimensional force applied to the pedals by cyclists in real conditions. The force platform was designed to be fitted on a conventional competition bicycle crankset while data is transmitted wirelessly through a Bluetooth™ module and also stored on a SD card. A 3D solid model is created in the SolidWorks (Dassault Systèmes SOLIDWORKS Corp.) to analyze the static and dynamic characteristics of the crank arm by using the finite elements technique. Each crankset arm is used as a load cell based on strain gauges configured as three Wheatstone bridges. The signals are conditioned on a printed circuit board attached directly to the structure. The load cell showed a maximum nonlinearity error between 0.36% and 0.61% and a maximum uncertainty of 2.3% referred to the sensitivity of each channel. A roller trainer equipped with an optical encoder was also developed, allowing the measurement of the wheel's instantaneous velocity.

  3. A New Crank Arm-Based Load Cell for the 3D Analysis of the Force Applied by a Cyclist

    PubMed Central

    Balbinot, Alexandre; Milani, Cleiton; Nascimento, Jussan da Silva Bahia

    2014-01-01

    This report describes a new crank arm-based force platform designed to evaluate the three-dimensional force applied to the pedals by cyclists in real conditions. The force platform was designed to be fitted on a conventional competition bicycle crankset while data is transmitted wirelessly through a BluetoothTM module and also stored on a SD card. A 3D solid model is created in the SolidWorks (Dassault Systèmes SOLIDWORKS Corp.) to analyze the static and dynamic characteristics of the crank arm by using the finite elements technique. Each crankset arm is used as a load cell based on strain gauges configured as three Wheatstone bridges. The signals are conditioned on a printed circuit board attached directly to the structure. The load cell showed a maximum nonlinearity error between 0.36% and 0.61% and a maximum uncertainty of 2.3% referred to the sensitivity of each channel. A roller trainer equipped with an optical encoder was also developed, allowing the measurement of the wheel's instantaneous velocity. PMID:25479325

  4. Splinting effect on posterior implants under various loading modes: a 3D finite element analysis.

    PubMed

    Hauchard, Erwan; Fournier, Benjamin Philippe; Jacq, Romain; Bouton, Antoine; Pierrisnard, Laurent; Naveau, Adrien

    2011-09-01

    This three-dimensional finite element study compared stresses, intensities and displacements of three mandibular posterior implants restored with cemented crowns (two molars and a premolar in straight line), splinted versus non-splinted. Hundred newton occlusal loads were vertically or horizontally applied, either on one single crown or on all of them. Maximal stresses and implants displacements were higher under horizontal loading. Splinting major effects appeared under single horizontal load with a decrease in stresses (34-49%) and displacements (16-19%) of the loaded crown. Splinting seems more appropriate for implant-supported restorations submitted to frequent single horizontal or oblique loads than vertical ones.

  5. Direct observation of crack opening as a function of applied load in the interior of a notched tensile sample of Al-Li 2090

    SciTech Connect

    Guvenilir, A.; Breunig, T.M.; Stock, S.R.; Kinney, J.H.

    1997-05-01

    Results of in situ high resolution X-ray computed tomography are reported for a notched tensile sample of Al-Li 2090 T841. The fatigue crack within the interior of the sample is imaged with 6 {micro}m voxels as a function of applied load, and the crack face morphology is found to be similar to that observed in compact tension samples of this alloy. The loads and approximate stress intensities at which the tomography data were obtained were 82, 50, 25 and 5 kg and 7.1, 4.3, 2.2 and 0.4 MPa{radical}m, respectively. Crack openings measured during unloading as a function of position show that physical closure at portions of the crack tip and at positions behind the crack tip precedes (during unloading) the bend in the sample`s load-displacement curve. The three-dimensional pattern of crack opening shows substantial mixed mode I-III contact on the faces of asperities behind the crack tip, even at the maximum load of the fatigue cycle. Mixed mode I-II contact is also observed at loads above the bend in the load-displacement curve. The fraction of voxels open remains nearly constant for the loads immediately above and below the nominal closure load, as determined from the load-displacement curve, of 41 kg; and this suggests that these mixed mode I-III surfaces begin to carry significant load at the point where the load-displacement curve starts to deflect, and is the source of the apparent stiffening of the sample at loads below the nominal closure load.

  6. The use of ultrasonic pulse velocity tests for the diagnosis of ancient masonries: the influence of the applied load

    NASA Astrophysics Data System (ADS)

    Leucci, Giovanni; Vasanelli, Emilia; Calia, Angela; Micelli, Francesco; Aiello, Maria Antonietta

    2014-05-01

    Sophisticated non destructive techniques for the diagnosis of existing masonry structures have been developed and improved throughout the years, such as ground penetrating radar, thermography, sonic and ultrasonic tomography, laser scanner survey, etc.: by using an integrated approach it is possible to reconstruct the morphology of the masonry walls, to detect the presence of cracks and voids, achieving an accurate and reliable diagnosis of the construction, which is the basis for the restoration design. The ultrasonic pulse velocity (UPV) method can be conveniently used to check the quality of stones, but it can be used also for material characterization. Both the intrinsic characteristic of the stone (porosity, grain size, anisotropy, etc.) and the external factors (humidity, stress, temperature, presence of cracks) may affect the elastic wave propagation, thus in order to correctly estimate the ultrasonic behaviour of the material investigated it is important to know in what manner and how much the variation of the experimental conditions may modify the characteristics of the waves being measured. This aspect is of crucial importance when in situ measurements are made. In this work the influence of the applied load on UPV results has been investigated. In particular, the research has been carried out on ashlars and on sample masonry panels made of lime mortar joints and Lecce stone, a soft calcarenitic stone traditionally used in the Lecce district, South of Italy. The presence of load strongly influenced the UPV measures, due to the particular microstructural characteristic of the stone. The work aim at quantify this influence in order to correctly interpret in situ measurements.

  7. Comparison of the respiratory responses to external resistive loading and bronchoconstriction.

    PubMed Central

    Kelsen, S G; Prestel, T F; Cherniack, N S; Chester, E H; Deal, E C

    1981-01-01

    The effects of resistive loads applied at the mouth were compared to the effects of bronchospasm on ventilation, respiratory muscle force (occlusion pressure), and respiratory sensations in 6 normal and 11 asthmatic subjects breathing 100% O2. External resistive loads ranging from 0.65 to 13.33 cm H2O/liter per s were applied during both inspiration and expiration. Bronchospasm was induced by inhalation of aerosolized methacholine. Bronchospasm increased ventilation, inspiratory airflow, respiratory rate, and lowered PACO2. External resistive loading, on the other hand, reduced respiratory rate and inspiratory flow, but left ventilation and PACO2 unaltered. FRC increased to a greater extent with bronchospasm than external flow resistive loads. With both bronchospasm and external loading, occlusion pressure increased in proportion to the rise in resistance to airflow. However, the change in occlusion pressure produced by a given change in resistance and the absolute level of occlusion pressure at comparable levels of airway resistance were greater during bronchospasm than during external loading. These differences in occlusion pressure responses to the two forms of obstruction were not explained by differences in chemical drive or respiratory muscle mechanical advantage. Although the subjects' perception of the effort involved in breathing was heightened during both forms of obstruction to airflow, at any given level of resistance the sense of effort was greater with bronchospasm than external loading. Inputs from mechanoreceptors in the lungs (e.g., irritant receptors) and/or greater stimulation of chest wall mechanoreceptors as a result of increases in lung elastance may explain the differing responses elicited by the two forms of resistive loading. PMID:6787083

  8. Simple model of dissolved oxygen consumption in a bay within high organic loading: an applied remediation tool.

    PubMed

    Ahumada, Ramón; Vargas, José; Pagliero, Liliana

    2006-07-01

    San Vicente Bay is a coastal shallow embayment in Central Chile with multiple uses, one of which is receiving wastewater from industrial fisheries, steel mill effluents, and domestic sewage. A simulation model was developed and applied to dissolved oxygen consumption by organic residues released into this embayment. Three compartments were established as function of: depth, circulation and outfall location. The model compartments had different volumes, and their oxygen saturation value was used as baseline. The parameters: (a) BOD5 of the industrial and urban effluents, (b) oxygen demand by organic sediments, (c) respiration, (d) photosynthesis and (e) re-aeration were included in the model. Iteration results of the model showed severe alterations in Compartment 1, with a decrease of 65% in the oxygen below saturation. Compartment 2 showed a small decline (10%) and compartment 3 did not show apparent changes in oxygen values. Measures recommended for remediation were to decrease the BOD5 loading by 30% in the affected sector. Iteration of the model for 200 h following recommendations derived from the preceding results produced an increase in saturation of 60% (5 ml O2 L(-1)), which suggested an improvement of the environmental conditions.

  9. Load cell

    DOEpatents

    Spletzer, Barry L.

    1998-01-01

    A load cell combines the outputs of a plurality of strain gauges to measure components of an applied load. Combination of strain gauge outputs allows measurement of any of six load components without requiring complex machining or mechanical linkages to isolate load components. An example six axis load cell produces six independent analog outputs, each directly proportional to one of the six general load components.

  10. Load cell

    DOEpatents

    Spletzer, B.L.

    1998-12-15

    A load cell combines the outputs of a plurality of strain gauges to measure components of an applied load. Combination of strain gauge outputs allows measurement of any of six load components without requiring complex machining or mechanical linkages to isolate load components. An example six axis load cell produces six independent analog outputs, each directly proportional to one of the six general load components. 16 figs.

  11. Load cell

    DOEpatents

    Spletzer, Barry L.

    2001-01-01

    A load cell combines the outputs of a plurality of strain gauges to measure components of an applied load. Combination of strain gauge outputs allows measurement of any of six load components without requiring complex machining or mechanical linkages to isolate load components. An example six axis load cell produces six independent analog outputs which can be combined to determine any one of the six general load components.

  12. A new approach to evaluating occlusal support by analyzing the center of the bite force.

    PubMed

    Shinogaya, Tatsuya; Tanaka, Yasuhiro; Toda, Sou; Hayakawa, Iwao

    2002-12-01

    The aim of this study was to create a standard for occlusal support in the diagnosis and evaluation of prosthetic treatment. In experimental occlusion, the maximal bite force of eight normal dentates was measured by pressure-sensitive film over the whole dentition using splints divided into nine pieces. The occlusal contact was altered by exchanging splint pieces according to the shortened dental arch concept. The occlusal load center (OLC) was located on a graph set up with reference to the size of the individual dental arch. The occlusal supporting index (SI) and the rehabilitation index (RI) were calculated from the locations of the OLC corresponding to each occlusal contact. Differences in numbers and distribution of occlusal stops could clearly be distinguished by the location of the OLC. Though the SI showed a strong positive correlation with maximal bite force, it is proposed that the number of occlusal stops, or occlusal units, provides the most effective index for quantitative parameters of occlusal support in clinical use. From the standpoint of bite force, analysis of the RI is suggested as a useful method of objectively evaluating the recovery of occlusal support with prosthetic treatment.

  13. AnSBBR applied to the treatment of metalworking fluid wastewater: effect of organic and shock load.

    PubMed

    Carvalhinha, Pedro P; Flôres, Anderson; Rodrigues, José A D; Ratusznei, Suzana M; Zaiat, Marcelo; Foresti, Eugenio

    2010-11-01

    An investigation was performed regarding the application of a mechanically stirred anaerobic sequencing batch biofilm reactor containing immobilized biomass on inert polyurethane foam (AnSBBR) to the treatment of soluble metalworking fluids to remove organic matter and produce methane. The effect of increasing organic matter and reactor fill time, as well as shock load, on reactor stability and efficiency have been analyzed. The 5-L AnSBBR was operated at 30 degrees C in 8-h cycles, agitation of 400 rpm, and treated 2.0 L effluent per cycle. Organic matter was increased by increasing the influent concentration (500, 1,000, 2,000, and 3,000 mg chemical oxygen demand (COD)/L). Fill times investigated were in the batch mode (fill time 10 min) and fed-batch followed by batch (fill time 4 h). In the batch mode, organic matter removal efficiencies were 87%, 86%, and 80% for influent concentrations of 500, 1,000, and 2,000 mgCOD/L (1.50, 3.12, and 6.08 gCOD/L.d), respectively. At 3,000 mgCOD/L (9.38 gCOD/L.d), operational stability could not be achieved. The reactor managed to maintain stability when a shock load twice as high the feed concentration was applied, evidencing the robustness of the reactor to potential concentration variations in the wastewater being treated. Increasing the fill time to 4 h did not improve removal efficiency, which was 72% for 2,000 mgCOD/L. Thus, gradual feeding did not improve organic matter removal. The concentration of methane formed at 6.08 gCOD/L was 5.20 mmolCH(4), which corresponded to 78% of the biogas composition. The behavior of the reactor during batch and fed-batch feeding could be explained by a kinetic model that considers organic matter consumption, production, and consumption of total volatile acids and methane production.

  14. Effects of applied stress ratio on the fatigue behavior of additively manufactured porous biomaterials under compressive loading.

    PubMed

    de Krijger, Joep; Rans, Calvin; Van Hooreweder, Brecht; Lietaert, Karel; Pouran, Behdad; Zadpoor, Amir A

    2016-12-07

    Additively manufactured (AM) porous metallic biomaterials are considered promising candidates for bone substitution. In particular, AM porous titanium can be designed to exhibit mechanical properties similar to bone. There is some experimental data available in the literature regarding the fatigue behavior of AM porous titanium, but the effect of stress ratio on the fatigue behavior of those materials has not been studied before. In this paper, we study the effect of applied stress ratio on the compression-compression fatigue behavior of selective laser melted porous titanium (Ti-6Al-4V) based on the diamond unit cell. The porous titanium biomaterial is treated as a meta-material in the context of this work, meaning that R-ratios are calculated based on the applied stresses acting on a homogenized volume. After morphological characterization using micro computed tomography and quasi-static mechanical testing, the porous structures were tested under cyclic loading using five different stress ratios, i.e. R = 0.1, 0.3, 0.5, 0.7 and 0.8, to determine their S-N curves. Feature tracking algorithms were used for full-field deformation measurements during the fatigue tests. It was observed that the S-N curves of the porous structures shift upwards as the stress ratio increases. The stress amplitude was the most important factor determining the fatigue life. Constant fatigue life diagrams were constructed and compared with similar diagrams for bulk Ti-6Al-4V. Contrary to the bulk material, there was limited dependency of the constant life diagrams to mean stress. The notches present in the AM biomaterials were the sites of crack initiation. This observation and other evidence suggest that the notches created by the AM process cause the insensitivity of the fatigue life diagrams to mean stress. Feature tracking algorithms visualized the deformation during fatigue tests and demonstrated the root cause of inclined (45°) planes of specimen failure. In conclusion, the R

  15. Cyclic Tensile Stress During Physiological Occlusal Force Enhances Osteogenic Differentiation of Human Periodontal Ligament Cells via ERK1/2-Elk1 MAPK Pathway

    PubMed Central

    Li, Lu; Han, Minxuan; Li, Sheng

    2013-01-01

    Physiological occlusal force constitutively exists in the oral environment and is important for periodontal homeostasis and remodeling. Cyclic tensile stress (CTS) triggers the biological response of periodontal ligament (PDL). However, a few reports have studied the correlation between CTS during physiological occlusal force and PDL cell activities such as osteogenic differentiation. In the present study, human PDL cells (hPDLCs) were subjected to 10% elongation CTS loading at 0.5 Hz for 24 h, which represents the physiological conditions of occlusal force. Gene expression microarray was used to investigate the mechano-induced differential gene profile and pathway analysis in vitro. The osteogenic relative factors, that is, SPP1, RUNX2, and SP7, were assessed by real-time PCR and Western blot. The involvement of mitogen-activated protein kinase (MAPK) signaling pathways was investigated by Western blot with a specific inhibitor. The expressions of SPP1, RUNX2, SP7, p-ERK1/2, and p-Elk1 were up-regulated after 10% CTS exposure. However, these up-regulated expressions were prevented by ERK1/2 inhibitor U0126 in the physiological occlusal force-applied hPDLCs. These results showed that 10% CTS could enhance osteogenic differentiation of hPDLCs via ERK1/2-Elk1 MAPK pathway, indicating that CTS during physiological occlusal force is a potent agent for PDL remodeling. PMID:23781879

  16. Occlusal trauma--periodontal concerns.

    PubMed

    Hallmon, W W

    2001-10-01

    While there is evidence that suggests that occlusal trauma is a risk factor for periodontal destruction, there is no evidence that indicates that occlusal trauma will initiate periodontal destruction. Effective plaque control and compliance with periodontal maintenance recommendations are key and essential factors necessary to assure successful treatment and control of periodontal disease.

  17. The Research on the Bionic Friction Layers of TiAl-10wt.%V2O5 Nanowires at the Applied Loads of 6-24 N

    NASA Astrophysics Data System (ADS)

    Yang, Kang; Shi, Xiaoliang; Zou, Jialiang; Radwan, Amr Rady; Ibrahim, Ahmed Mohamed Mahmoud; Li, Xuewu; Huang, Yuchun; Shen, Qiao

    2016-12-01

    The objective of searching the optimum applied load was to minimize friction and decrease wear in mechanical moving components. The friction and wear behaviors of TiAl-10wt.%V2O5 nanowires (TiAl-10wt.%V2O5) were evaluated sliding against the fixed Al2O3 balls with the Vickers hardness of 18.07 GPa at the applied loads of 6-24 N. The testing results showed that the smaller friction coefficient and wear rate of TiAl-10wt.%V2O5 were obtained at 18 N, if compared to those at 6, 12 and 24 N. The smaller friction coefficient and wear rate were mainly attributed to the forming of cambiform structure of large crystalline grain, the higher totals of oxide interionic potential and the higher thickness of friction layer at 18 N, if compared to those at the other applied loads. It was obvious that the applied load of 18 N was reasonable for obtaining the lower sliding friction coefficient and the less wear rate of TiAl-10wt.%V2O5.

  18. [Temporomandibular joint, occlusion and bruxism].

    PubMed

    Orthlieb, J D; Ré, J P; Jeany, M; Giraudeau, A

    2016-09-01

    Temporomandibular joint and dental occlusion are joined for better and worse. TMJ has its own weaknesses, sometimes indicated by bad functional habits and occlusal disorders. Occlusal analysis needs to be addressed simply and clearly. The term "malocclusion" is not reliable to build epidemiological studies, etiologic mechanisms or therapeutic advice on this "diagnosis". Understanding the impact of pathogenic malocclusion is not just about occlusal relationships that are more or less defective, it requires to locate them within the skeletal framework, the articular and behavioural context of the patient, and above all to assess their impact on the functions of the masticatory system. The TMJ-occlusion couple is often symbiotic, developing together in relation to its environment, compensating for its own shortcomings. However, a third partner may alter this relationship, such as bruxism, or more generally oral parafunctions, trauma or an interventionist practitioner.

  19. Basilar Occlusion Syndromes

    PubMed Central

    Broderick, Joseph P.

    2015-01-01

    Basilar artery occlusions (BAOs) are a subset of posterior circulation strokes. Particular issues relevant to BAOs include variable and stuttering symptoms at onset resulting in delays in diagnosis, high morbidity and mortality, and uncertain best management. Despite better imaging techniques, diagnosis, and therefore treatment, is often delayed. We will present the most common signs and symptoms of posterior circulation strokes. Data on optimal treatment strategies are gathered from multiple case series, registries, and one randomized trial, which was stopped early. Possible etiologies of BAOs, acute, and subacute treatment strategies and special topics in neuroimaging of the posterior fossa are discussed. This review may be helpful to neurohospitalists who are managing patients with acute stroke as well as emergency room physicians and neurologists. PMID:26288672

  20. Evaluation of constraint methodologies applied to a shallow-flaw cruciform bend specimen tested under biaxial loading conditions

    SciTech Connect

    Bass, B.R.; McAfee, W.J.; Williams, P.T.; Pennell, W.E.

    1998-01-01

    A technology to determine shallow-flaw fracture toughness of reactor pressure vessel (RPV) steels is being developed for application to the safety assessment of RPVs containing postulated shallow surface flaws. Matrices of cruciform beam tests were developed to investigate and quantify the effects of temperature, biaxial loading, and specimen size on fracture initiation toughness of two-dimensional (constant depth), shallow surface flaws. The cruciform beam specimens were developed at Oak Ridge National Laboratory (ORNL) to introduce a prototypic, far-field. out-of-plane biaxial stress component in the test section that approximates the nonlinear stresses resulting from pressurized-thermal-shock or pressure-temperature loading of an RPV. Tests were conducted under biaxial load ratios ranging from uniaxial to equibiaxial. These tests demonstrated that biaxial loading can have a pronounced effect on shallow-flaw fracture toughness in the lower transition temperature region for RPV materials. The cruciform fracture toughness data were used to evaluate fracture methodologies for predicting the observed effects of biaxial loading on shallow-flaw fracture toughness. Initial emphasis was placed on assessment of stress-based methodologies. namely, the J-Q formulation, the Dodds-Anderson toughness scaling model, and the Weibull approach. Applications of these methodologies based on the hydrostatic stress fracture criterion indicated an effect of loading-biaxiality on fracture toughness, the conventional maximum principal stress criterion indicated no effect.

  1. Lateral occlusion schemes in natural and minimally restored permanent dentition: a systematic review.

    PubMed

    Abduo, J; Tennant, M; McGeachie, J

    2013-10-01

    Clinicians commonly encounter the dilemma of which lateral occlusion schemes is most suitable for a specific patient. The aim of this review is to evaluate the prevalence of the lateral occlusion schemes that exist naturally. An electronic search was completed through PubMed (MEDLINE), Google Scholar and Cochrane Library. The search was confined to peer-reviewed studies published in English, up to April 2013. The literature search was supplemented by manual searching through the bibliography lists of the selected studies. The initial search retrieved a total of 575 studies. After applying the selection criteria, only 12 studies were suitable for inclusion. The Critical Appraisal Skills Programme (CASP) tools were utilised to appraise the quality of the studies. The prevalence of canine-guided, group function and balanced occlusions was reported. Overall, there was a clear variability between the studies. The prevalence of the lateral occlusion schemes appears to be influenced by the following factors: (i) the magnitude of excursion, (ii) an individual's age and (iii) the static occlusal relationship. During complete excursion, the canine-guided occlusion tends to be more frequently observed. After partial excursion, the most prevalent lateral occlusion schemes was group function occlusion. With ageing, the prevalence of canine-guided occlusion tends to be reduced and the prevalence of group function occlusion is increased. Dentition that is closer to Class II occlusion exhibits mainly canine-guided occlusion, while for Class III occlusion, group function occlusion is more prevalent. The studies revealed no relationship between the lateral occlusion schemes and TMD development.

  2. A finite element study to determine the occurrence of abfraction and displacement due to various occlusal forces and with different alveolar bone height

    PubMed Central

    Vandana, Kharidhi Laxman; Deepti, Mittal; Shaimaa, Muneer; Naveen, Karnath; Rajendra, Desai

    2016-01-01

    Background: Noncarious cervical lesions (NCCLs) are rarely described in the periodontal literature, perhaps because no direct link between NCCLs and periodontal lesions has been demonstrated. Aim: The aim of this study is to determine the stress and displacement produced in the tooth at different bone levels under different occlusal load using finite element model (FEM) study. Materials and Methods: Four FEMs of maxillary incisor were designed consisting of the tooth, pulp, periodontal ligament, and alveolar bone at the various level of bone height (25%, 50%, and 75%). Different occlusal load (5 kg, 15 kg, 24 kg, and 29 kg) at an angle of 50° to the long axis of the tooth was applied on the palatal surface at the level of middle third of the crown. All the models were assumed to be isotropic, linear and elastic, and the analysis was performed on a Pentium IV processor computer using the ANSYS software. Results: The maximum stress in the tooth was seen in the cervical region and to a greater extent at the apex for all models. The maximum tooth displacement for all the occlusal loads applied in this study was at the incisal edge with the minimum tooth displacement at the cervical third of the root which shifted apically with the reduction of alveolar bone support. Conclusion: The cumulative effect of increased stress and displacement at the cervical region of the tooth would result in abfraction as the age advances along with other wasting diseases. PMID:27041831

  3. Non-occlusive mesenteric ischemia.

    PubMed

    Lock, G; Schölmerich, J

    1995-07-01

    Non-occlusive disease of the mesentery is still a rather underdiagnosed and underestimated condition. It is associated with circumstances that may compromise circulation or the intake of drugs that may lower mesenteric blood flow. Pathophysiologically, a "low flow syndrome" of mesenteric circulation is followed by vasoconstriction; a reperfusion injury may contribute to the ischemic injury. Histopathological changes vary between superficial localized lesions and transmural gangrene. Diagnosis within the initial 24 hours of the development of symptoms is crucial for prognosis but remains a difficult task. Clinical presentation, laboratory tests and ultrasound lack specificity; the role of duplex ultrasound, tonometry and reflectance spectophotometry is still under evaluation. Mesenteric angiography remains the only reliable diagnostic tool and should be applied early in all patients in whom acute mesenteric ischemia is a real possibility. Therapy is aimed at the rapid correction of predisposing and precipitating factors and an effective treatment of mesenteric vasoconstriction. Treatment of choice is a papaverine infusion into the superior mesenteric artery via an angiography catheter. Patients with peritoneal signs have to be treated surgically.

  4. Runoff and phosphorus loads from two row-cropped fields with and without applied manure, 2000-2011

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Adequate characterization of runoff water quality from agricultural fields under a changing climate will require years of monitoring. This study compared runoff volumes and phosphorus loads from two fields in central Iowa. Both fields were in corn-soybean rotation, but with only one receiving swine ...

  5. Deficient Attention Is Hard to Find: Applying the Perceptual Load Model of Selective Attention to Attention Deficit Hyperactivity Disorder Subtypes

    ERIC Educational Resources Information Center

    Huang-Pollock, Cynthia L.; Nigg, Joel T.; Carr, Thomas H.

    2005-01-01

    Background: Whether selective attention is a primary deficit in childhood Attention Deficit Hyperactivity Disorder (ADHD) remains in active debate. Methods: We used the "perceptual load" paradigm to examine both early and late selective attention in children with the Primarily Inattentive (ADHD-I) and Combined subtypes (ADHD-C) of ADHD. Results:…

  6. The influence of walking with an orthosis on bone mineral density by determination of the absolute values of the loads applied on the limb.

    PubMed

    Karimi, Mohammad Taghi

    2012-03-01

    Spinal cord injury is damage to the spinal cord that results in loss of mobility and sensation below the level of injury. Most patients use various types of orthoses to stand and walk. It has been claimed that walking and standing with orthosis reduces bone osteoporosis, improves joint range of motion and decreases muscle spasm. Unfortunately, there are discrepancies regarding the clinical effects of walking and standing on bone mineral density. The aim of this research was to find the absolute values of the loads transmitted by body and orthosis in walking with use of an orthosis. 5 normal subjects were recruited to stand and walk with a new design of reciprocal gait orthosis. The loads transmitted through the orthosis and anatomy was measured by use of strain gauge and motion analysis systems. It has been shown that the loads applied on the anatomy were significantly more than that transmitted through the orthosis. Moreover, the patterns of the forces and moments of the orthosis and body completely differed from each other. As the most part of the loads applied on the complex transmitted by anatomy in walking with an orthosis, walking with orthosis can influence bone mineral density.

  7. Cognitive Load and Self-Determination Theories Applied to E-Learning: Impact on Students' Participation and Academic Performance

    PubMed Central

    de Araujo Guerra Grangeia, Tiago; de Jorge, Bruno; Franci, Daniel; Martins Santos, Thiago; Vellutini Setubal, Maria Silvia; Schweller, Marcelo; de Carvalho-Filho, Marco Antonio

    2016-01-01

    Background Emergency clerkships expose students to a stressful environment that require multiple tasks, which may have a direct impact on cognitive load and motivation for learning. To address this challenge, Cognitive Load Theory and Self Determination Theory provided the conceptual frameworks to the development of a Moodle-based online Emergency Medicine course, inspired by real clinical cases. Methods Three consecutive classes (2013–2015) of sixth-year medical students (n = 304) participated in the course, during a curricular and essentially practical emergency rotation. “Virtual Rounds” provided weekly virtual patients in narrative format and meaningful schemata to chief complaints, in order to simulate real rounds at Emergency Unit. Additional activities such as Extreme Decisions, Emergency Quiz and Electrocardiographic challenge offered different views of emergency care. Authors assessed student´s participation and its correlation with their academic performance. A survey evaluated students´ opinions. Students graduating in 2015 answered an online questionnaire to investigate cognitive load and motivation. Results Each student produced 1965 pageviews and spent 72 hours logged on. Although Clinical Emergency rotation has two months long, students accessed the online course during an average of 5.3 months. Virtual Rounds was the most accessed activity, and there was positive correlations between the number of hours logged on the platform and final grades on Emergency Medicine. Over 90% of students felt an improvement in their clinical reasoning and considered themselves better prepared for rendering Emergency care. Considering a Likert scale from 1 (minimum load) to 7 (maximum load), the scores for total cognitive load were 4.79±2.2 for Virtual Rounds and 5.56±1.96 for real medical rounds(p<0,01). Conclusions A real-world inspired online course, based on cognitive and motivational conceptual frameworks, seems to be a strong tool to engage students in

  8. Measurement of regional forearm muscle haemodynamics via the near-infrared spectroscopy venous occlusion technique: the impact of hand circulatory occlusion.

    PubMed

    Cross, T J; van Beekvelt, M; Constantini, K; Sabapathy, S

    2014-12-01

    The purpose of this study was to examine whether circulatory occlusion of the hand impacts on regional forearm muscle haemodynamics as determined by the near-infrared spectroscopy (NIRS) venous occlusion technique (NIRSVOT). Twenty-five young, healthy participants (18 males and 7 females; 28 ± 4 years; 71 ± 7 kg) completed two experimental protocols that were performed on the dominant arm: (1) a series of five venous occlusion trials with a suprasystolic cuff (>260 mmHg) applied to the wrist and (2) five venous occlusion trials without hand-occlusion. Both protocols were performed twice in a counterbalanced manner. NIRS data were obtained from the flexor digitorum superficialis (FDS) muscle using a dual wavelength, continuous-wave spectrophotometer. FDS muscle blood flow (Q(FDS)), vascular conductance (C(FDS)), O2 consumption (Vo(2FDS)), and venous O2 saturation (SvO2) were calculated from NIRS data during the initial 5 s of venous occlusion. Circulatory occlusion of the hand via wrist cuffing significantly (P < 0.05) reduced Q(FDS) (-36 ± 23%), CFDS (-37 ± 23%), Vo2(FDS) (-14 ± 31%) and SvO2 (-14 ± 12%). These findings indicate that hand-occlusion, via wrist cuffing, adversely impacts on regional forearm haemodynamics as determined by the NIRS-VOT. Consequently, it is recommended that future investigators avoid hand-occlusion when using the NIRS-VOT to quantify spontaneous haemodynamics of regional forearm muscle.

  9. Crack initiation at high loading rates applying the four-point bending split Hopkinson pressure bar technique

    NASA Astrophysics Data System (ADS)

    Henschel, Sebastian; Krüger, Lutz

    2015-09-01

    Dynamic crack initiation with crack-tip loading rates of K˙ ≈ 2.106MPa√ms-1 in a high strength G42CrMoS4 steel was investigated. To this end, a previously developed split Hopkinson pressure bar with four-point bending was utilised. V-notched and pre-cracked Charpy specimens were tested. The detection of dynamic crack initiation was performed by analysing the dynamic force equilibrium between the incident and the transmission bar. Additionally, the signal of a near-field strain gauge and high-speed photography were used to determine the instant of crack initiation. To account for vibrations of the sample, a dynamic analysis of the stress intensity factor was performed. The dynamic and static analyses of the tests produced nearly the same results when a force equilibrium was achieved. Fracture-surface analysis revealed that elongated MnS inclusions strongly affected both the dynamic crack initiation and growth. Blunting of the precrack did not take place when a group of MnS inclusions was located directly at the precrack tip. Due to the direction of the elongated MnS inclusions perpendicular to the direction of crack growth, the crack could be deflected. The comparison with a 42CrMo4 steel without elongated MnS inclusions revealed the detrimental effect in terms of resistance to crack initiation. Taking the loading-rate dependency into consideration, it was shown that there was no pronounced embrittlement due to the high loading rates.

  10. Endoluminal occlusion devices: technology update

    PubMed Central

    Zander, Tobias; Medina, Samantha; Montes, Guillermo; Nuñez-Atahualpa, Lourdes; Valdes, Michel; Maynar, Manuel

    2014-01-01

    Endoluminal occlusion has been performed since the early beginning of interventional radiology. Over recent decades, major technological advances have improved the techniques used and different devices have been developed for changing conditions. Most of these occlusion devices have been implemented in the vascular territory. Early embolization materials included glass particles, hot contrast, paraffin, fibrin, and tissue fragments such as muscle fibers and blood clots; today, occlusion materials include metallic devices, particles, and liquid materials, which can be indicated for proximal or distal occlusion, high-flow and low-flow situations, and in large-caliber and small-caliber vessels, based on need. Technological progress has led to a decreased size of delivery catheters, and an increase in safety due to release systems that permit the withdrawing and replacement of embolization material. Furthermore, bioactive embolization materials have been developed to increase the efficacy of embolization or the biological effect of medication. Finally, materials have been modified for changing indications. Intravascular stents were initially developed to keep an artery open; however, by adding a covering membrane, these stents can be used to occlude the wall of a vessel or other endoluminal structures. This article gives an overview of the devices most utilized for occlusion of endoluminal structures, as well as their major purpose in the endovascular territory. PMID:25489252

  11. Ball's motion, sliding friction, and internal load distribution in a high-speed ball bearing subjected to a combined radial, thrust, and moment load, applied to the inner ring's center of mass: Numerical procedure

    NASA Astrophysics Data System (ADS)

    César Ricci, Mário

    2015-10-01

    In a companion paper of this was introduced a set of non-linear algebraic equations for ball's motion, sliding friction and internal loading distribution computation in a high-speed, single-row, angular-contact ball bearing, subjected to a known combined radial, thrust and moment load, which must be applied to the inner ring's center of mass. It was shown there that it is required the iterative solution of 9Z + 3 simultaneous non-linear equations - where Z is the number of balls - to yield exact solution for contact angles, ball attitude angles, rolling radii, normal contact deformations and axial, radial, and angular deflections of the inner ring with respect the outer ring. The Newton-Rhapson method is to be used to solve the problem. This paper deals with the numerical procedure description. The numerical results derived from the described procedure shall be published later.

  12. Occlusion as a measure for visual workload: an overview of TNO occlusion research in car driving.

    PubMed

    van der Horst, Richard

    2004-05-01

    A process-oriented approach by systematically studying driver performance, distraction, and workload is the way to go for assessing safety effects of new telematics applications in vehicles. These systems may strive for drivers' attention and possibly lead to distraction from the primary task. Visual occlusion techniques appear to be an effective means of studying drivers' visual information processing performance. Studies to illustrate this include identifying the minimum visual information drivers need for driving (asking for visual information) and the evaluation of driver support systems such as heading control and adaptive cruise control with respect to visual workload. In other applications the occlusion technique is used to exclude 'visual array' information from the optic flow field. The temporary exclusion of part of the visual field of view was applied in evaluating the effects of different types of driver's side rearview mirrors.

  13. Reducing Nitrogen loadings to estuaries in Denmark, 1990-2010. Results and costs of measures applied in catchments to 10 Danish estuaries

    NASA Astrophysics Data System (ADS)

    Windolf, J.; Blicher-Mathiesen, G.; Carstensen, N. J.; Kronvang, B.

    2012-04-01

    The Nitrogen loading to 10 Danish estuaries has since 1990 been reduced by on average 42%. Thirty percent of this reduction is due to a reduction in Nitrogen loss from diffuse sources. Nitrogen surplus and the change in this surplus is shown to be a strong overall indicator for the trends in Nitrogen loading to most estuaries. The Nitrogen surplus has been reduced due to general national regulations and mitigation measures applied leading to an increased efficiency of Nitrogen use in cattle slurry (30%) and in pig slurry (ca. 40%). These improvements are paralleled by a reduced application of commercial N-fertilizer. Mean flow-weighted total Nitrogen concentrations in inlet fresh waters to estuaries have been reduced by 18-56% resulting in reductions of total Nitrogen concentrations (24-62%) in the inner and middle parts of the estuaries. The large variations in total Nitrogen loadings and concentrations in estuaries are due to both attenuation and time delays of Nitrogen in groundwater aquifers depending on catchment soil type and geology. This also implies varying costs of reducing the Nitrogen loadings from agricultural land (24-94 Euro/kg N reduced). Knowledge of the outcome of responses in the form of national regulations of agricultural N management for the N cycling from field to estuaries is important for decision makers and catchment managers working with the implementation of EU Directives such as the Water Framework Directive. Based on our findings we suggest that further reductions of Nitrogen loadings from agricultural land should be based on targeted and catchment specific measures leading to the most cost efficient way to achieve good ecological quality in the individual estuaries.

  14. 'Occlusal sketch'; a reliable technique for technicians to check that the occlusion of models is correct?

    PubMed

    Davies, Stephen J; Al-Ani, Ziad; Richmond, Raymond; Worthington, Helen V; Smith, Philip W

    2005-06-01

    The aim of this study was to determine whether the occlusal sketch technique can be used as a reliable means of verifying the occlusal contacts on articulated casts. Occlusal markings were made on 30 sets of upper and lower dentate casts and these were recorded using the 'occlusal sketch' technique. Fifteen out of the total 30 pairs of casts were deliberately corrupted by the clinician so that they no longer matched the record on the 'occlusal sketch'. Three dental technicians were asked to judge in which of the 30 casts the occlusal contacts differed from those represented by the occlusal sketch. The results showed almost perfect agreement between the technicians in correctly identifying which casts had marked occlusal contacts which differed from those recorded on the occlusal sketch. The occlusal sketch provides a reliable way of communicating occlusal contacts that occur in a case, between clinician and technician.

  15. A method for three-dimensional displacement and deformation measurement applied to the statically loaded middle ear ossicles

    NASA Astrophysics Data System (ADS)

    Decraemer, Willem F.; Gea, Stefan L.; Maas, Steve A.; Dirckx, Joris J. J.

    2008-06-01

    The middle ear ossicles transmit sound from eardrum to inner ear under largely varying ambient pressure conditions. To protect the structures within the cochlea from excessive footplate incursions the configuration of the ossicles changes with pressure. Sequences of micro CT-scans were acquired from gerbil temporal bones under static ear canal pressures ranging from -450 to +450 daPa. These image stacks were used to track the 3D motion and deformations of the ossicles as a function of pressure using hyperelastic warping. Using the scans for zero pressure, accurate finite-element reference models were generated for each of the ossicles. With the difference between these template images and the target image data recorded in a deformed configuration as a driving force, the warping algorithm displaced and deformed the finite-element models of the ossicles in order to align the deformed template with the target data. Position changes of the ossicles within the middle ear cavity and deformation of the ossicles and the tympanic membrane were all measured in a same preparation. For each static pressure load a finite-element ossicular chain model is obtained in the run and can be used for further analysis under acoustic stimulation.

  16. Plant- and stimulus-specific variations in remote-controlled sieve-tube occlusion.

    PubMed

    Furch, Alexandra Cu; Hafke, Jens B; van Bel, Aart Je

    2008-10-01

    Phloem injury triggers local sieve-plate occlusion including callose-mediated constriction and protein plugging of sieve pores. In intact plants, reversible sieve-plate occlusion is induced by electric potential waves (EPWs)-accompanied by Ca(2+)-influx-as result of distant burning. Here, we present additional results which pertain to (a) the variability of EPW-profiles in relation to forisome conformation in intact Vicia faba plants and (b) the differential occlusion reactions to burning and cutting in various plant species. A correlation between stimulus perception and mode of phloem loading is discussed.

  17. Pulmonary veno-occlusive disease

    MedlinePlus

    ... disorder. Alternative Names Pulmonary vaso-occlusive disease Images Respiratory system References Chin K, Channick RN. Pulmonary hypertension. In: Broaddus VC, Mason RJ, Ernst JD, et al, eds. Murray and Nadel's Textbook of Respiratory Medicine . 6th ed. Philadelphia, PA: Elsevier Saunders; 2016: ...

  18. Trauma from occlusion. Periodontal concerns.

    PubMed

    Burgett, F G

    1995-04-01

    Application of the chronic disease model to IPD suggests that to be most effective, programs of prevention and treatment include measures to address as many of the identified risk factors as is possible. It remains to be determined if TO is involved in the initiation of IPD, for example, if individuals with TO are at greater risk for the development of IPD. There is evidence that TO is a risk factor in the progression of IPD. Tooth mobility is associated with and is a risk factor for increased attachment loss and increased bone loss in patients with periodontitis. Tooth mobility can be reduced by occlusal treatment. Clinical trials involving patients with periodontitis clearly establish that a better clinical periodontal attachment level response to treatment is obtained when occlusal adjustment is included as part of the treatment plan. Patients with advanced periodontal involvement benefit from occlusal treatment in terms of increased stability for the teeth and also in terms of oral comfort. Finally, There is no evidence that without occlusal treatment, periodontal patients who are in careful maintenance programs are more likely to suffer recurrence of IPD.

  19. An analysis of the loads applied to a heavy Space Station rack during translation and rotation tasks

    NASA Astrophysics Data System (ADS)

    Stoycos, Lara E.; Klute, Glenn K.

    1994-02-01

    To prepare for Space Station Alpha's on-orbit assembly, maintenance, and resupply, NASA requires information about the crew members' ability to move heavy masses on orbit. Ease of movement in microgravity and orbiter stay time constraints may change the Space Station equipment and outfitting design requirements. Therefore, the time and effort required to perform a particular task and how and where the forces and torque should be applied become critical in evaluating the design effort. Thus, the three main objectives of this investigation were to: (1) quantify variables such as force and torque as they relate to heavy mass handling techniques; (2) predict the time required to perform heavy mass handling tasks; and (3) note any differences between males and females in their ability to manipulate a heavy mass.

  20. An analysis of the loads applied to a heavy Space Station rack during translation and rotation tasks

    NASA Technical Reports Server (NTRS)

    Stoycos, Lara E.; Klute, Glenn K.

    1994-01-01

    To prepare for Space Station Alpha's on-orbit assembly, maintenance, and resupply, NASA requires information about the crew members' ability to move heavy masses on orbit. Ease of movement in microgravity and orbiter stay time constraints may change the Space Station equipment and outfitting design requirements. Therefore, the time and effort required to perform a particular task and how and where the forces and torque should be applied become critical in evaluating the design effort. Thus, the three main objectives of this investigation were to: (1) quantify variables such as force and torque as they relate to heavy mass handling techniques; (2) predict the time required to perform heavy mass handling tasks; and (3) note any differences between males and females in their ability to manipulate a heavy mass.

  1. Dynamic Modelling of Tooth Deformation Using Occlusal Kinematics and Finite Element Analysis

    PubMed Central

    Benazzi, Stefano; Nguyen, Huynh Nhu; Kullmer, Ottmar; Kupczik, Kornelius

    2016-01-01

    Background Dental biomechanics based on finite element (FE) analysis is attracting enormous interest in dentistry, biology, anthropology and palaeontology. Nonetheless, several shortcomings in FE modeling exist, mainly due to unrealistic loading conditions. In this contribution we used kinematics information recorded in a virtual environment derived from occlusal contact detection between high resolution models of an upper and lower human first molar pair (M1 and M1, respectively) to run a non-linear dynamic FE crash colliding test. Methodology MicroCT image data of a modern human skull were segmented to reconstruct digital models of the antagonistic right M1 and M1 and the dental supporting structures. We used the Occlusal Fingerprint Analyser software to reconstruct the individual occlusal pathway trajectory during the power stroke of the chewing cycle, which was applied in a FE simulation to guide the M1 3D-path for the crash colliding test. Results FE analysis results showed that the stress pattern changes considerably during the power stroke, demonstrating that knowledge about chewing kinematics in conjunction with a morphologically detailed FE model is crucial for understanding tooth form and function under physiological conditions. Conclusions/Significance Results from such advanced dynamic approaches will be applicable to evaluate and avoid mechanical failure in prosthodontics/endodontic treatments, and to test material behavior for modern tooth restoration in dentistry. This approach will also allow us to improve our knowledge in chewing-related biomechanics for functional diagnosis and therapy, and it will help paleoanthropologists to illuminate dental adaptive processes and morphological modifications in human evolution. PMID:27031836

  2. Computational evaluation of aortic occlusion and the proposal of a novel, improved occluder: Constrained endo-aortic balloon occlusion.

    PubMed

    de Vaal, M H; Gee, M W; Stock, U A; Wall, W A

    2016-12-01

    Because aortic occlusion is arguably one of the most dangerous aortic manipulation maneuvers during cardiac surgery in terms of perioperative ischemic neurological injury, the purpose of this investigation is to assess the structural mechanical impact resulting from the use of existing and newly proposed occluders. Existing (clinically used) occluders considered include different cross-clamps (CCs) and endo-aortic balloon occlusion (EABO). A novel occluder is also introduced, namely, constrained EABO (CEABO), which consists of applying a constrainer externally around the aorta when performing EABO. Computational solid mechanics are employed to investigate each occluder according to a comprehensive list of functional requirements. The potential of a state of occlusion is also considered for the first time. Three different constrainer designs are evaluated for CEABO. Although the CCs were responsible for the highest strains, largest deformation, and most inefficient increase of the occlusion potential, it remains the most stable, simplest, and cheapest occluder. The different CC hinge geometries resulted in poorer performance of CC used for minimally invasive procedures than conventional ones. CEABO with a profiled constrainer successfully addresses the EABO shortcomings of safety, stability, and positioning accuracy, while maintaining its complexities of operation (disadvantage) and yielding additional functionalities (advantage). Moreover, CEABO is able to achieve the previously unattainable potential to provide a clinically determinable state of occlusion. CEABO offers an attractive alternative to the shortcomings of existing occluders, with its design rooted in achieving the highest patient safety. Copyright © 2016 John Wiley & Sons, Ltd.

  3. Incompressible viscous flow in tubes with occlusions

    NASA Astrophysics Data System (ADS)

    Huang, Huaxiong

    Viscous, incompressible flow in tubes with partial occlusion is investigated using numerical and experimental procedures. The study is related to the problem of atherosclerosis, one of the most common diseases of the circulatory system. One of the computational difficulties in solving the incompressible Navier-Stokes equations is the lack of pressure or vorticity boundary conditions. A finite difference approach, referred to as the interior constraint (IC) method, is proposed to resolve this difficulty. As a general numerical method, it is formulated for both the stream function-vorticity and primitive (physical) variable formulations. The procedure is explained using a one dimensional model with extensive numerical tests presented for two dimensional cases, including flow in a driven cavity and flow over a backward facing step. Results are obtained with second-order accuracy. Next, the IC method is applied to flow in a tube with an occlusion, which is used as the model for blood flow in stenosed arteries in the study of the pathology of atherosclerosis. Numerical results are obtained for both steady and pulsatile flows. Results are compared with those of SIMPLE, one of the commercially available numerical algorithms. The pulsatile flow study revealed several interesting new features. It suggested that the high shear stress is not likely to initiate atherosclerosis lesions. The recirculation region, which is a prominent feature of the unsteady flow, is more likely to cause the initiation and development of the disease. Experimental measurements for steady flow complement the numerical study and show qualitative agreement.

  4. AnSBBR applied to a personal care industry wastewater treatment: effects of fill time, volume treated per cycle, and organic load.

    PubMed

    Rodrigues, José Alberto Domingues; Oliveira, Ricardo Polisaitis; Ratusznei, Suzana Maria; Zaiat, Marcelo; Foresti, Eugenio

    2011-01-01

    A study was performed regarding the effect of the relation between fill time, volume treated per cycle, and influent concentration at different applied organic loadings on the stability and efficiency of an anaerobic sequencing batch reactor containing immobilized biomass on polyurethane foam with recirculation of the liquid phase (AnSBBR) applied to the treatment of wastewater from a personal care industry. Total cycle length of the reactor was 8 h (480 min). Fill times were 10 min in the batch operation, 4 h in the fed-batch operation, and a 10-min batch followed by a 4-h fed batch in the mixed operation. Settling time was not necessary since the biomass was immobilized and decant time was 10 min. Volume of liquid medium in the reactor was 2.5 L, whereas volume treated per cycle ranged from 0.88 to 2.5 L in accordance with fill time. Influent concentration varied from 300 to 1,425 mg COD/L, resulting in an applied volumetric organic load of 0.9 and 1.5 g COD/L.d. Recirculation flow rate was 20 L/h, and the reactor was maintained at 30 °C. Values of organic matter removal efficiency of filtered effluent samples were below 71% in the batch operations and above 74% in the operations of fed batch followed by batch. Feeding wastewater during part of the operational cycle was beneficial to the system, as it resulted in indirect control over the conversion of substrate into intermediates that would negatively interfere with the biochemical reactions regarding the degradation of organic matter. As a result, the average substrate consumption increased, leading to higher organic removal efficiencies in the fed-batch operations.

  5. Carotid bypass for carotid occlusion.

    PubMed

    Hage, Ziad A; Behbahani, Mandana; Amin-Hanjani, Sepideh; Charbel, Fady T

    2015-07-01

    The 2-year risk of ipsilateral ischemic stroke following internal carotid artery occlusion (ICAO) in a patient undergoing maximal medical therapy is 5-8% per year. While medical therapy may reduce the risk of stroke, it does not completely eliminate it. Since the 1985 extracranial-intracranial (EC-IC) bypass study, additional trials have been conducted to further investigate the usefulness of EC-IC bypass surgery in more selected patients with cerebral ischemia and impaired hemodynamic reserve. These important studies will be briefly reviewed in this article, as well as a discussion regarding the utility of bypass surgery for ICAO in current clinical practice. In addition, a short discussion regarding the pathophysiology of carotid occlusion will be presented. We will also highlight our own institutional patient selection criteria based on the latest methods for hemodynamic assessment, as well as our intraoperative flow assisted surgical techniques (FAST), and post-operative patient follow-up.

  6. A new crank arm based load cell, with built-in conditioning circuit and strain gages, to measure the components of the force applied by a cyclist.

    PubMed

    Pigatto, Andre V; Moura, Karina O A; Favieiro, Gabriela W; Balbinot, Alexandre

    2016-08-01

    This report describes the development of a force platform based on instrumented load cells with built-in conditioning circuit and strain gages to measure and acquire the components of the force that is applied to the bike crank arm during pedaling in real conditions, and save them on a SD Card. To accomplish that, a complete new crank arm 3D solid model was developed in the SolidWorks, with dimensions equivalent to a commercial crank set and compatible with a conventional road bike, but with a compartment to support all the electronics necessary to measure 3 components of the force applied to the pedal during pedaling. After that, a 6082 T6 Aluminum Crankset based on the solid model was made and instrumented with three Wheatstone bridges each. The signals were conditioned on a printed circuit board, made on SMD technology, and acquired using a microcontroller with a DAC. Static deformation analysis showed a linearity error below 0.6% for all six channels. Dynamic analysis showed a natural frequency above 136Hz. A one-factor experiment design was performed with 5 amateur cyclists. ANOVA showed that the cyclist weight causes significant variation on the force applied to the bicycle pedal and its bilateral symmetry.

  7. Estimates of Vertical Velocity Errors for IGS ITRF2014 Stations by Applying the Improved Singular Spectrum Analysis Method and Environmental Loading Models

    NASA Astrophysics Data System (ADS)

    Klos, Anna; Gruszczynska, Marta; Bos, Machiel Simon; Boy, Jean-Paul; Bogusz, Janusz

    2017-02-01

    A reliable subtraction of seasonal signals from the Global Positioning System (GPS) position time series is beneficial for the accuracy of derived velocities. In this research, we propose a two-stage solution of the problem of a proper determination of seasonal changes. We employ environmental loading models (atmospheric, hydrological and ocean non-tidal) with a dominant annual signal of amplitudes in their superposition of up to 12 mm and study the seasonal signal (annual and semi-annual) estimates that change over time using improved singular spectrum analysis (ISSA). Then, this deterministic model is subtracted from GPS position time series. We studied data from 376 permanent International GNSS Service (IGS) stations, derived as the official contribution to International Terrestrial Reference Frame (ITRF2014) to measure the influence of applying environmental loading models on the estimated vertical velocity. Having removed the environmental loadings directly from the position time series, we noticed the evident change in the power spectrum for frequencies between 4 and 80 cpy. Therefore, we modelled the seasonal signal in environmental models using the ISSA approach and subtracted it from GPS vertical time series to leave the noise character of the time series intact. We estimated the velocity dilution of precision (DP) as a ratio between classical Weighted Least Squares and ISSA approach. For a total number of 298 out of the 376 stations analysed, the DP was lower than 1. This indicates that when the ISSA-derived curve was removed from the GPS data, the error of velocity becomes lower than it was before.

  8. [Acute arterial occlusion associated disseminated hydatidosis].

    PubMed

    Somocurcio, Jose; Alvarez, Gamero; Lara Campos, Gloria; Cahuana Aparco, Judith; Calongos Porras, Estefanny; Bermejo Cataño, Pedro; Tejada Llacsa, Paul

    2014-04-01

    Hydatidosis or echinococcosis are terms used to denote the zoonotic infestation caused by adult and larval stages (metacestode) of the cestode from the genus Echinococcus (family tenidae). The term hydatidosis should be applied to the infestation caused by the metacestode while echinococcosis for the larval and adult stages. In Peru there is a high prevalence of this infection, liver and lung being the most affected organs. There are factors from the host and from the infectious agent that contribute to this infection, with the immune component of the host as an important infection and dissemination point. A case of acute arterial occlusion associated with disseminated hydatidosis in a 54 years old patient, born and from Huancavelica, with sudden onset of an acute arterial obstruction is reported. The patient did not improve after surgery and died within 48 hours of presentation.

  9. Interaction effects of organic load and cycle time in an AsBr applied to a personal care industry wastewater treatment.

    PubMed

    Oliveira, Ricardo Polisaitis; Ratusznei, Suzana Maria; Rodrigues, José Alberto Domingues; Zaiat, Marcelo; Foresti, Eugenio

    2010-12-01

    A mechanically stirred anaerobic sequencing batch reactor (ASBR) containing granular biomass was applied to the treatment of a wastewater simulating the effluent from a personal care industry. The ASBR was operated with cycle lengths (t(C)) of 8, 12 and 24 h and applied volumetric organic loads (AVOL) of 0.75, 0.50 and 0.25 gCOD/L.d, treating 2.0 L liquid medium per cycle. Stirring frequency was 150 rpm and the reactor was kept in an isothermal chamber at 30 °C. Increase in t(C) resulted in efficiency increase at constant AVOL, reaching 77% at t(C) of 24 h versus 69% at t(C) of 8 h. However, efficiency decreased when AVOL decreased as a function of increasing t(C), due to the lack of substrate in the reaction medium. Moreover, replacing part of the wastewater by a chemically balanced synthetic one did not yield the expected effect and system efficiency dropped.

  10. ACUTE RETINAL ARTERIAL OCCLUSIVE DISORDERS

    PubMed Central

    Hayreh, Sohan Singh

    2011-01-01

    The initial section deals with basic sciences; among the various topics briefly discussed are the anatomical features of ophthalmic, central retinal and cilioretinal arteries which may play a role in acute retinal arterial ischemic disorders. Crucial information required in the management of central retinal artery occlusion (CRAO) is the length of time the retina can survive following that. An experimental study shows that CRAO for 97 minutes produces no detectable permanent retinal damage but there is a progressive ischemic damage thereafter, and by 4 hours the retina has suffered irreversible damage. In the clinical section, I discuss at length various controversies on acute retinal arterial ischemic disorders. Classification of acute retinal arterial ischemic disorders These are of 4 types: CRAO, branch retinal artery occlusion (BRAO), cotton wools spots and amaurosis fugax. Both CRAO and BRAO further comprise multiple clinical entities. Contrary to the universal belief, pathogenetically, clinically and for management, CRAO is not one clinical entity but 4 distinct clinical entities – non-arteritic CRAO, non-arteritic CRAO with cilioretinal artery sparing, arteritic CRAO associated with giant cell arteritis (GCA) and transient non-arteritic CRAO. Similarly, BRAO comprises permanent BRAO, transient BRAO and cilioretinal artery occlusion (CLRAO), and the latter further consists of 3 distinct clinical entities - non-arteritic CLRAO alone, non-arteritic CLRAO associated with central retinal vein occlusion and arteritic CLRAO associated with GCA. Understanding these classifications is essential to comprehend fully various aspects of these disorders. Central retinal artery occlusion The pathogeneses, clinical features and management of the various types of CRAO are discussed in detail. Contrary to the prevalent belief, spontaneous improvement in both visual acuity and visual fields does occur, mainly during the first 7 days. The incidence of spontaneous visual

  11. Endovascular recanalization techniques for popliteal arterial occlusive injury with limb-threatening ischemia secondary to trauma.

    PubMed

    Mine, Takahiko; Murata, Satoru; Yasui, Daisuke; Tajima, Hiroyuki; Kawamata, Hiroshi; Yokota, Hiroyuki; Kumita, Shin-Ichiro

    2014-01-01

    To date, no ideal endovascular strategy has been established for traumatic arterial occlusion. Here, we report the outcomes of a combination of endovascular recanalization techniques applied in two patients with high risk of leg amputation. A 33-year-old man with popliteal artery occlusion due to blunt trauma was treated by balloon angioplasty with long inflation time and aspiration thrombectomy. A 74-year-old woman with popliteal artery occlusion after total knee replacement was treated by aspiration thrombectomy and stent placement. In both cases, we achieved satisfactory recanalization, and peripheral ischemia was absent even 1 year later.

  12. Occlusion in the combination fixed removable prosthodontic patient.

    PubMed

    Ivanhoe, J R; Vaught, R D

    1987-07-01

    The authors provide a review of the critical aspects of occlusion for the combination fixed removable patient. Articular selection and jaw relation techniques are reviewed, and dental materials combinations are recommended for restoring opposing occlusal surfaces. General objectives and specific recommendations for determining and establishing occlusal schemes are made. Tables outlining occlusal scheme, occlusal morphology, and degree of balance are presented.

  13. [Hemodynamic adaptations in proximal cerebrovascular occlusion].

    PubMed

    De Ley, G

    1990-01-01

    In order to gain more insight into the pathophysiology of extracerebral cerebrovascular occlusion, the cerebral hemodynamic behaviour after uni- or bilateral carotid occlusion was investigated. In Wistar rats, acute occlusion of one common carotid artery leads to a moderate bilateral lowering of the resting hemispheric brain blood flow; no interhemispheric perfusion asymmetry is observed. During hypercapnia, however, a manyfold increase of the hemispheric blood flow is seen at the intact side, whereas blood flow increase at the side of the occlusion is suppressed indicating that the cerebrovascular reserve at the side of the occlusion is largely used to preserve resting hemispheric perfusion. During the days (1, 5, 15 and 30) following the occlusion, resting hemispheric blood flow is progressively restored rather rapidly (bilateral normalization on the fifth day) whereas restoration of the cerebrovascular reserve (hemispheric blood flow increase in hypercapnia) proceeds more slowly and a nearly normal hypercapnic response is reached on day thirty. Spontaneously Hypertensive Rats (SHR) show structural abnormalities of their blood vessels during the development of hypertension, leading to impaired adaptation possibilities of the cerebral vasculature after unilateral common carotid occlusion. This is indicated by the striking comparability of the compensation of hemispheric cerebral blood flow (in normo- and hypercapnia) of SH rats five days after unilateral carotid occlusion with the cerebral hemodynamic status of normotensive animals already seen 24 hours after the same occlusion. Consecutive bilateral common carotid occlusion shows that survival rate increases by increasing the interval between both occlusions. This survival relation is much more unfavorable in SH rats. The parallelism between the restoration of the measured CO2-reactivity of the blood flow in the involved hemisphere after unilateral carotid occlusion and the evolution of survival rate after

  14. Cost aggregation and occlusion handling with WLS in stereo matching.

    PubMed

    Min, Dongbo; Sohn, Kwanghoon

    2008-08-01

    This paper presents a novel method for cost aggregation and occlusion handling for stereo matching. In order to estimate optimal cost, given a per-pixel difference image as observed data, we define an energy function and solve the minimization problem by solving the iterative equation with the numerical method. We improve performance and increase the convergence rate by using several acceleration techniques such as the Gauss-Seidel method, the multiscale approach, and adaptive interpolation. The proposed method is computationally efficient since it does not use color segmentation or any global optimization techniques. For occlusion handling, which has not been performed effectively by any conventional cost aggregation approaches, we combine the occlusion problem with the proposed minimization scheme. Asymmetric information is used so that few additional computational loads are necessary. Experimental results show that performance is comparable to that of many state-of-the-art methods. The proposed method is in fact the most successful among all cost aggregation methods based on standard stereo test beds.

  15. Applied Pathology for Interventions of Coronary Chronic Total Occlusion

    PubMed Central

    Villa-Bellosta, Ricardo

    2015-01-01

    Elevated serum phosphorus has emerged as a key risk factor for pathologic calcification of cardiovascular structures, or vascular calcification (VC). To prevent the formation of calciumphosphate deposits (CPD), the body uses adenosine-5’-triphosphate (ATP) to synthesize inhibitors of calcification, including proteins and inhibitors of low molecular weight. Extracellular pyrophosphate (PPi) is a potent inhibitor of VC, which is produced during extracellular hydrolysis of ATP. Loss of function in the enzymes and transporters that are involved in the cycle of extracellular ATP, including Pi transporters, leads to excessive deposition of calcium-phosphate salts. Treatment of hyperphosphatemia with Pi-binders and Injection of exogenous PPi are the effective treatments to prevent CPD in the aortic wall. The role of sodium phosphate cotransporters in ectopic calcification is contradictory and not well defined, but their important role in the control of intracellular Pi levels and the synthesis of ATP make them an important target to study.

  16. Applied Pathology for Interventions of Coronary Chronic Total Occlusion

    PubMed Central

    Tran, Phillip; Phan, Hung; Shah, Sara R; Latif, Faisal; Nguyen, Thach

    2015-01-01

    Percutaneous coronary intervention of chronically occluded vessels can result in significant improvement in symptoms, relieve myocardial ischemia, and affect a reduction in major adverse cardiac events. Likelihood of achieving successful revascularization can be significantly enhanced with a thorough understanding of the pathology of these occluded coronary arteries. In this chapter, various steps and techniques to cross the CTO lesion and recanalize it are discussed in details.

  17. Occlusion on oral implants: current clinical guidelines.

    PubMed

    Koyano, K; Esaki, D

    2015-02-01

    Proper implant occlusion is essential for adequate oral function and the prevention of adverse consequences, such as implant overloading. Dental implants are thought to be more prone to occlusal overloading than natural teeth because of the loss of the periodontal ligament, which provides shock absorption and periodontal mechanoreceptors, which provide tactile sensitivity and proprioceptive motion feedback. Although many guidelines and theories on implant occlusion have been proposed, few have provided strong supportive evidence. Thus, we performed a narrative literature review to ascertain the influence of implant occlusion on the occurrence of complications of implant treatment and discuss the clinical considerations focused on the overloading factors at present. The search terms were 'dental implant', 'dental implantation', 'dental occlusion' and 'dental prosthesis'. The inclusion criteria were literature published in English up to September 2013. Randomised controlled trials (RCTs), prospective cohort studies and case-control studies with at least 20 cases and 12 months follow-up interval were included. Based on the selected literature, this review explores factors related to the implant prosthesis (cantilever, crown/implant ratio, premature contact, occlusal scheme, implant-abutment connection, splinting implants and tooth-implant connection) and other considerations, such as the number, diameter, length and angulation of implants. Over 700 abstracts were reviewed, from which more than 30 manuscripts were included. We found insufficient evidence to establish firm clinical guidelines for implant occlusion. To discuss the ideal occlusion for implants, further well-designed RCTs are required in the future.

  18. The effect of occlusal forces on restorations.

    PubMed

    Larson, Thomas D

    2014-09-01

    This review will focus on the effect occlusal forces, both normal masticatory force and paranormal bruxing and clenching force, have on various restorative materials and their interaction with the teeth through a variety of bonding mechanisms. Salient physical properties of each of the materials will be reviewed, as well as the effect occlusal force has on restoration durability.

  19. Symposium on semiprecision attachments in removable partial dentures. Occlusal relationships.

    PubMed

    Whitbeck, P; Ivanhoe, J R

    1985-01-01

    This article discusses current concepts of occlusion and describes the methods of creating a physiologic occlusion for the partially edentulous patient. Specific recommendations are made for choices of materials, techniques, and occlusal schemes for various edentulous situations.

  20. Computerized analysis of occlusal contacts in bruxism patients treated with occlusal splint therapy

    PubMed Central

    Kılınç, Halil İbrahim; Tuna, Süleyman Hakan; Özcan, Nihal

    2013-01-01

    PURPOSE Occlusal splints are commonly used to prevent tooth wear caused by bruxism. However, the effects of splints on occlusion are still unclear. Although it is rarely alluded in literature, splints can provoke severe occlusal alterations and other complications. This study was aimed to identify differences in the responses of individuals with bruxism and healthy individuals to a full-arch maxillary stabilization splint in terms of occlusal changes. MATERIALS AND METHODS Occlusal contacts in 20 (5 male, 15 female) bruxism patients and 20 (5 male, 15 female) controls with normal occlusion were evaluated before and after occlusal splint therapy. T-Scan III, a computerized occlusal analysis system, was used to simultaneously measure occlusion and disclusion times as well as left-right and anterior-posterior contact distributions before splint therapy and 3 months after therapy. Wilcoxon and Mann-Whitney U tests were used for statistical analyses (α=.05). RESULTS No differences were found in the posterior contact of bruxism patients before and after stabilization splint treatment. However, differences in posterior contact were observed between bruxists and normal individuals prior to treatment, and this difference disappeared following treatment. CONCLUSION The results of this study showed the use of a stabilization splint may not have an effect on occlusion. However, the area of posterior occlusal contact among bruxists was found to be greater than that of normal individuals. According to this study, the clinical use of splints may be harmless. PMID:24049566

  1. Anatomical significance in aortoiliac occlusive disease.

    PubMed

    Wooten, Candace; Hayat, Munawar; du Plessis, Maira; Cesmebasi, Alper; Koesterer, Michael; Daly, Kevin P; Matusz, Petru; Tubbs, R Shane; Loukas, Marios

    2014-11-01

    Aortoiliac occlusive disease is a subset of peripheral arterial disease involving an atheromatous occlusion of the infrarenal aorta, common iliac arteries, or both. The disease, as it is known today, was described by the French surgeon René Leriche as a thrombotic occlusion of the end of the aorta. Leriche successfully linked the anatomic location of the occlusion with a unique triad of symptoms, including claudication, impotence, and decreased peripheral pulses. The anatomical location of the atheromatous lesions also has a direct influence on classification of the disease, as well as choice of treatment modality. Considering its impact on diagnosis and treatment, we aimed to provide a detailed understanding of the anatomical structures involved in aortoiliac occlusive disease. Familiarity with these structures will aid the physician in interpretation of radiologic images and surgical planning.

  2. Functional Aesthetic Occlusal Plane (FAOP)

    PubMed Central

    Câmara, Carlos Alexandre; Martins, Renato Parsekian

    2016-01-01

    ABSTRACT Introduction: A reasonable exposure of incisors and gingival tissues is generally considered more attractive than excess or lack of exposure. A reasonable gingival exposure is considered to be around 0 to 2 mm when smiling and 2-4 mm exposure of the maxillary incisor edge when the lips are at rest. Objective: The aim of this paper is to present the Functional Aesthetic Occlusal Plane (FAOP), which aims to help in the diagnosis of the relationships established among molars, incisors and the upper lip. Conclusion: FAOP can complement an existing and established orthodontic treatment plan, facilitating the visualization of functional and aesthetic demands by giving a greater focus on the position of incisors in the relationship established among the incisors, molars and the upper lip stomion. PMID:27653271

  3. Special report: Occlusive cuff controller

    NASA Technical Reports Server (NTRS)

    Baker, J. T.

    1975-01-01

    A mechanical occlusive cuff controller suitable for blood flow experiments in space shuttle flights is described. The device requires 115 volt ac power and a pressurized gas source. Two occluding cuff pressures (30 and 50 mmHg) are selectable by a switch on the front panel. A screw driver adjustment allows accurate cuff pressurization levels for under or oversized limbs. Two pressurization cycles (20 second and 2 minutes) can be selected by a front panel switch. Adjustment of the timing cycles is also available through the front panel. A pushbutton hand switch allows remote start of the cuff inflation cycle. A stop/reset switch permits early termination of the cycle and disabling of the controller to prevent inadvertent reactivation. Pressure in the cuff is monitored by a differential aneroid barometer. In addition, an electrocardiogram trigger circuit permits the initiation of the pressurization cycle by an externally supplied ECG cycle.

  4. Occlusion for stimulus deprivation amblyopia

    PubMed Central

    Antonio-Santos, Aileen; Vedula, Satyanarayana S; Hatt, Sarah R; Powell, Christine

    2014-01-01

    Background Stimulus deprivation amblyopia (SDA) develops due to an obstruction to the passage of light secondary to a condition such as cataract. The obstruction prevents formation of a clear image on the retina. SDA can be resistant to treatment, leading to poor visual prognosis. SDA probably constitutes less than 3% of all amblyopia cases, although precise estimates of prevalence are unknown. In developed countries, most patients present under the age of one year; in less developed parts of the world patients are likely to be older at the time of presentation. The mainstay of treatment is removal of the cataract and then occlusion of the better-seeing eye, but regimens vary, can be difficult to execute, and traditionally are believed to lead to disappointing results. Objectives Our objective was to evaluate the effectiveness of occlusion therapy for SDA in an attempt to establish realistic treatment outcomes. Where data were available, we also planned to examine evidence of any dose response effect and to assess the effect of the duration, severity, and causative factor on the size and direction of the treatment effect. Search methods We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2013, Issue 9), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to October 2013), EMBASE (January 1980 to October 2013), the Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to October 2013), PubMed (January 1946 to October 2013), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 28 October 2013. Selection criteria We planned

  5. Trauma from occlusion. Restorative concerns.

    PubMed

    Neff, P

    1995-04-01

    Trauma from occlusion and restorative concerns may affect the tooth itself, the supporting structures inside and around the tooth's immediate structures, and the total articulating system, which includes the neuromuscular system, the temporomandibular joints, and other systems such as the impairment of hearing or vision and many other peripheral conditions. A thorough examination and a differential diagnosis procedure is essential to restore the health of the articulating system and reverse peripheral condition. This includes the ability to restore the individual tooth in its best anatomic position as a complement to the articulating system using all individual disciplines of dentistry in the finest abilities of treatment and the ability to share and distinguish the possible parafunctional habits and the need for behavioral understanding, support, and management to limit or lessen the wear and destruction of the individual tissues and to restore a healthier physical support.

  6. Hyperaemic changes in forearm skin perfusion and RBC concentration after increasing occlusion times.

    PubMed

    Farnebo, Simon; Thorfinn, Johan; Henricson, Joakim; Tesselaar, Erik

    2010-12-01

    Tissue occlusion and the hyperaemic response upon reperfusion can be used as a tool to assess microvascular function in various vascular diseases. Currently, laser Doppler flowmetry (LDF) is applied most often to measure hyperaemic responses. In this study, we have applied tissue viability imaging (TiVi) and LDF to measure the change in red blood cell concentration and perfusion in the skin after occlusions of the forearm with increasing duration. We have found that there is a strong correlation between the changes in perfusion and red blood cell (RBC) concentration during post-occlusive hyperaemia (perfusion: r=0.80; RBC concentration: r=0.94). This correlation increases with longer occlusion durations (1, 5 and 10min). Furthermore, for both perfusion and RBC concentration, the maximum responses (perfusion: r(2)=0.59; RBC concentration: r(2)=0.78) and the recovery times (perfusion: r(2)=0.62; RBC concentration: r(2)=0.91) increase linearly with the duration of the occlusion. Maximum responses and recovery times were more reproducible for RBC concentration (as measured with TiVi) than for perfusion (as measured with LDF). These results show that perfusion and RBC concentration are related during post-occlusive hyperaemia and that TiVi can be used as a tool in the assessment of hyperaemic responses that has advantages in terms of reproducibility, sensitivity and ease of use.

  7. Comparison of occlusion pressure and ventilatory responses.

    PubMed Central

    Lederer, D H; Altose, M D; Kelsen, S G; Cherniack, N S

    1977-01-01

    The airway pressure 100 msec after the onset of an inspiratory effort against a closed airway (P100, occlusion pressure) is theoretically a more accurate index of respiratory neuron motor output than ventilation. Occlusion pressure and ventilation responses to hypercapnia were compared in repeated trials in 10 normal subjects while in the seated and supine positions. During progressive hypercapnia changes in P100 were also compared to changes in tidal volume and inspiratory airflow. These studies show that occlusion pressure increases linearly with hypercapnia in both sitting and supine subjects. Changing from the seated to the supine position, or vice versa, had no significant effect on either ventilation or occlusion pressure responses to CO2. Correlations between P100 and ventilation or airflow rate were significantly higher than correlations between P100 and tidal volume or breathing frequency. Intermittent random airway occlusion had no effect on either ventilation or pattern of breathing during hypercapnia. Occlusion pressure responses were no less variable than ventilation responses in groups of subjects whether studied seated or supine. However, maintenance of a constant moderate breathing frequency (20 breaths per minute) reduced the interindividual variability in ventilation and occlusion pressure responses to hypercapnia. PMID:867336

  8. Pulmonary veno-occlusive disease.

    PubMed

    Montani, David; Lau, Edmund M; Dorfmüller, Peter; Girerd, Barbara; Jaïs, Xavier; Savale, Laurent; Perros, Frederic; Nossent, Esther; Garcia, Gilles; Parent, Florence; Fadel, Elie; Soubrier, Florent; Sitbon, Olivier; Simonneau, Gérald; Humbert, Marc

    2016-05-01

    Pulmonary veno-occlusive disease (PVOD) is a rare form of pulmonary hypertension (PH) characterised by preferential remodelling of the pulmonary venules. In the current PH classification, PVOD and pulmonary capillary haemangiomatosis (PCH) are considered to be a common entity and represent varied expressions of the same disease. The recent discovery of biallelic mutations in the EIF2AK4 gene as the cause of heritable PVOD/PCH represents a major milestone in our understanding of the molecular pathogenesis of PVOD. Although PVOD and pulmonary arterial hypertension (PAH) share a similar clinical presentation, with features of severe precapillary PH, it is important to differentiate these two conditions as PVOD carries a worse prognosis and life-threatening pulmonary oedema may occur following the initiation of PAH therapy. An accurate diagnosis of PVOD based on noninvasive investigations is possible utilising oxygen parameters, low diffusing capacity for carbon monoxide and characteristic signs on high-resolution computed tomography of the chest. No evidence-based medical therapy exists for PVOD at present and lung transplantation remains the preferred definitive therapy for eligible patients.

  9. Workflow Optimization in Vertebrobasilar Occlusion

    SciTech Connect

    Kamper, Lars Meyn, Hannes; Nordmeyer, Simone; Kempkes, Udo; Piroth, Werner

    2012-06-15

    Objective: In vertebrobasilar occlusion, rapid recanalization is the only substantial means to improve the prognosis. We introduced a standard operating procedure (SOP) for interventional therapy to analyze the effects on interdisciplinary time management. Methods: Intrahospital time periods between hospital admission and neuroradiological intervention were retrospectively analyzed, together with the patients' outcome, before (n = 18) and after (n = 20) implementation of the SOP. Results: After implementation of the SOP, we observed statistically significant improvement of postinterventional patient neurological status (p = 0.017). In addition, we found a decrease of 5:33 h for the mean time period from hospital admission until neuroradiological intervention. The recanalization rate increased from 72.2% to 80% after implementation of the SOP. Conclusion: Our results underscore the relevance of SOP implementation and analysis of time management for clinical workflow optimization. Both may trigger awareness for the need of efficient interdisciplinary time management. This could be an explanation for the decreased time periods and improved postinterventional patient status after SOP implementation.

  10. Polycythemia causing posterior segment vascular occlusions

    PubMed Central

    Ganesan, Suganeswari; Raman, Rajiv; Sharma, Tarun

    2017-01-01

    A 44-year-old male patient presented with features suggestive of transient central retinal artery occlusion (CRAO) followed by permanent CRAO and lateral posterior ciliary artery occlusion. He had diagnostic features of polycythemia vera (PV). When presented for the first time, the patient had features of ocular ischemia such as ocular pain, conjunctival congestion, and retinal opacification but with normal arm-to-retina time and normal arteriovenous transit time. During the second presentation, he had ocular pain, congested conjunctiva, retinal opacification, cherry red spot with box-carrying of retinal vessels, and choroidal infarct (Amalric's sign). He had lost light perception in that eye. Patients with polycythemia are prone to multifocal vascular occlusions and this can be the presenting feature in PV. A timely diagnosis and prompt management can prevent these repeated thromboembolic occlusive episodes. PMID:28298862

  11. Stent Graft in Managing Juxta-Renal Aortoiliac Occlusion

    SciTech Connect

    Prabhudesai, V. Mitra, K.; West, D. J.; Dean, M. R. E.

    2003-09-15

    Endovascular procedures are frequently used as an alternative to surgical bypass in aortic and iliac occlusion. Stents have revolutionized the scope of such endovascular procedures, but there are few reports of stents or stent grafts in occlusive juxta-renal aortic occlusion. We present a case where such occlusion was managed by use of a stent graft with successful outcome.

  12. Stenting in Acute Lower Limb Arterial Occlusions

    SciTech Connect

    Raja, Jowad; Munneke, Graham; Morgan, Robert; Belli, Anna-Maria

    2008-07-15

    Management of critical limb ischemia of acute onset includes surgical embolectomy, bypass grafting, aspiration thrombectomy, thrombolysis, and mechanical thrombectomy followed by treatment of the underlying cause. We present our experience with the use of stents to treat acute embolic/thrombotic occlusions in one iliac and three femoropopliteal arteries. Although this is a small case series, excellent immediate and midterm results suggest that stenting of acute occlusions of the iliac, superficial femoral, and popliteal arteries is a safe and effective treatment option.

  13. Collagenase Total Occlusion-1 (CTO-1) Trial

    PubMed Central

    Strauss, Bradley H.; Osherov, Azriel B.; Radhakrishnan, Sam; Mancini, G.B. John; Manners, Allison; Sparkes, John D.; Chisholm, Robert J.

    2014-01-01

    Background Percutaneous interventions for chronic total occlusions have low success rates, primarily because of failure of guide wire crossing. Collagen-rich matrix constitutes the main barrier to chronic total occlusion crossing. In preclinical studies, local delivery of a bacterial collagenase formulation improved guide wire crossing. The Collagenase Total Occlusion-1 (CTO-1) Trial is a phase I, dose-escalation trial to assess the safety and efficacy of collagenase therapy to facilitate guide wire crossing in coronary artery chronic occlusions. Methods and Results Twenty subjects with ≥1 previous failure of chronic total occlusion guide wire crossing were enrolled at 2 sites. Subjects were treated in 4 distinct cohorts of 5 patients, with escalation of collagenase dose in each cohort from 300 to 1200 μg. Collagenase was locally delivered into the occlusions with either an over-the-wire balloon system (n=8) or a fine-cross microcatheter (n=12) for a period of 30 minutes. Subjects were brought back to the catheterization laboratory for guide wire crossing and angioplasty the next day. Guide wire crossing was successfully achieved in 15 subjects (75%). A soft-tip guide wire (Whisper, Pilot-50, Fielder XT) was either the sole or predominant guide wire used in 75% of successful crossings. Non–ST-segment–elevation myocardial infarctions occurred in 3 patients as a result of side-branch ischemia during stenting. Computed tomographic angiography at 3 months showed no late complications and patent stents in successfully treated chronic total occlusion. Anginal improvement occurred with a reduction in Canadian Cardiovascular Society class from baseline to 3 months (2.5±0.6 versus 0.9±0.9; P<0.001). Conclusion Local delivery of collagenase into coronary chronic total occlusion is feasible and safe with encouraging guide wire crossing results in previously failed cases. Larger clinical trials are required to determine efficacy. Clinical Trial Registration URL: http

  14. [Lingualized occlusion in the South African context].

    PubMed

    Oberholzer, T G; Geerts, G A V M

    2002-01-01

    The search for the ideal artificial tooth arrangement that maximizes denture stability, comfort, aesthetics, and function has occupied the dental literature for many years and still continues to do so. Of the many occlusal schemes that have been presented to the dental profession, that of lingualized occlusion has emerged as one of the more popular. The popularity of lingualized occlusion stems from the simplicity and flexibility of the concept and from its wide application to clinical practice (Parr & Ivanhoe, 1996). The registration of a repeatable correct centric jaw relation is not always possible. We don't know whether the patient will use centric relation during normal function. It is therefore useful to provide the patient with some freedom of movement around centric. lingualized occlusion provides freedom in centric. For many dentists the arrangement of artificial denture teeth into balanced occlusion is difficult and time consuming. As a result this task is most often performed by the dental technician. In the South African countryside dental laboratories are often far away. If dentists perform the arrangement of the denture teeth, time and costs can be saved. The mounting of denture teeth in lingualized occlusion is simple and fast. This will motivate dentists to arrange denture teeth themselves, with obvious benefits for both the patient and the dentist. The School of Oral Health Sciences of the University of Stellenbosch teaches this concept to its undergraduate students in order to improve the prosthetic service to the large edentulous population of South Africa.

  15. Clinical and microbiological aspects of the Sargon immediate load implant.

    PubMed

    Nowzari, H; Chee, W; Tuan, A; Abou-Rass, M; Landesman, H M

    1998-07-01

    A maxillary lateral incisor with severe periodontal destruction was extracted after forced eruption and was replaced with a Sargon Immediate Load Implant. The clinical and microbiological results of the case are reported. The Sargon Immediate Load Implant is an apically expandable, quintapodal, root-form dental implant, designed to be loaded immediately with a provisional fixed restoration in normal occlusion.

  16. Real-time scale-adaptive correlation filters tracker with depth information to handle occlusion

    NASA Astrophysics Data System (ADS)

    Pi, Jiatian; Gu, Yuzhang; Hu, Keli; Cheng, Xiaoliu; Zhan, Yunlong; Wang, Yingguan

    2016-07-01

    In visual object tracking, occlusions significantly undermine the performance of tracking algorithms. RGB-D cameras, such as Microsoft Kinect or the related PrimeSense camera, are widely available to consumers. Great attention has been focused on exploiting depth information for object tracking in recent years. We propose an algorithm that improves the existing correlation filter-based tracker for scale-adaptive tracking. Moreover, we utilize depth information provided by the Kinect camera to handle various types of occlusions. First, the optimal location of the target is obtained by the conventional kernelized correlation filter tracker. Then, we make use of the discriminative correlation filter for scale estimation as an independent part. At last, to further improve the tracking performance under occlusions, we present a simple yet effective occlusion handling mechanism to detect occlusion and recovery. In this mechanism, cluster analysis and object segmentation by K-means method have been applied to depth data. Numerous experiments on Princeton RGB-D tracking dataset demonstrate that the proposed algorithm outperforms several state-of-the-art trackers by successfully dealing with occlusions.

  17. Evaluation of Treatments in Patients with Nocturnal Bruxism on Bite Force and Occlusal Contact Area: A preliminary report

    PubMed Central

    Alkan, Alper; Bulut, Emel; Arici, Selim; Sato, Shuichi

    2008-01-01

    Objectives The purpose of this study was to investigate the short-term effects of occlusal splint therapy and tricyclic antidepressants on the bite force and occlusal contact area of patients presenting with nocturnal bruxism. Methods A maxillary full-coverage hard acrylic splint was applied to the five patients (Group S). Five patients took a tricyclic antidepressant (Amitriptiline HCl, 10 mg/day) for 3 months (Group A) and a control group (Group C) comprising of 10 dental school students with normal occlusion was also formed. Using a Dental Prescale (Fuji Photo Film Corporation, Tokyo, Japan) and an Occluzer computer (FPD703, Fuji Photo Film Corporation, Tokyo, Japan) the bite force and occlusal contact area were measured. The evaluations were made just before the treatment and at 1 month and 3 months of treatment. Results The bite force and occlusal contact area before treatment in study Groups A and S were found to be higher than those in the Group C. Furthermore, the bite force and occlusal contact area increased during treatment in Group A whilst they decreased in Group S. Bite force and occlusal contact area in Group S were lower at both 1 month and 3 months of treatment than in Group C. Conclusions It could be tentatively suggested that occlusal splint therapy may be more effective than tricyclic antidepressant in the treatment of bruxism. Further investigations of this measurement method involving larger study populations and a longer follow-up period are needed. PMID:19212534

  18. Effect of repeated vertical loads on microleakage of IRM and calcium sulfate-based temporary fillings.

    PubMed

    Liberman, R; Ben-Amar, A; Frayberg, E; Abramovitz, I; Metzger, Z

    2001-12-01

    Temporary fillings are commonly used to seal endodontic access cavities between visits. IRM and Cavidentin were selected to represent two widely used groups of temporary filling materials. The first is a reinforced zinc oxide-eugenol preparation that is mixed at chairside, whereas the second is a ready-to-use calcium sulfate-based material that gained popularity due to its convenience of application. The seal provided by the aforementioned materials was studied using a radioactive tracer quantitative assay. When compared as passive temporary filling, the two provided a similar quality of seal. However, when subjected to repetitive "occlusal" cyclic loading of 4 kg, IRM was clearly superior to the calcium sulfate-based material. Whereas IRM maintained a reasonable seal, the calcium sulfate-based fillings deteriorated and lost the ability to seal. These results suggest that even though calcium sulfate-based materials may be useful when not subjected to any occlusal forces, IRM should be preferred whenever occlusal loads may be applied. Furthermore it is demonstrated that testing such materials for microleakage with no reference to mastication forces may be of limited value.

  19. Endovascular Treatment Strategies in Aortoiliac Occlusion

    SciTech Connect

    Ozkan, Ugur Oguzkurt, Levent Tercan, Fahri Gumus, Burcak

    2009-05-15

    The aim of this study was to report our experience in endovascular treatment of total aortoiliac occlusion. Five patients who underwent endovascular recanalization procedures including manual aspiration thrombectomy, balloon angioplasty, and stent placement for total aortoiliac occlusion in a 4-year period were reviewed retrospectively. The mean age of patients was 51 years (range, 43 to 58 years). All patients had abdominal aorta and bilateral common iliac artery occlusion with or without external iliac artery occlusion. All patients either had a contraindication to surgery or refused it. Initial technical success was obtained in four of five (80%) patients. Endovascular techniques were successful in four patients who had good distal runoff and short-segment aortoiliac occlusion, but failed in a patient who had the worst distal runoff and long-segment aortoiliac occlusion. We observed two major complications, one of which was bilateral rupture of the common iliac arteries treated with covered stent placement. Another patient had extension of intra-aortic thrombus into the iliac stent after primary stenting. This was successfully treated with manual aspiration thrombectomy. Aortic and iliac stents remained patent during the follow-up period (median, 18 months; range, 3 to 26 months) in four patients. Primary patency rates at 6, 12, and 24 months were all 80%. In conclusion, endovascular treatment can be an alternative for aortoiliac occlusion in selected patients. Short- to midterm follow-up so far is satisfactory. Removal of intra-aortic thrombus with manual aspiration thrombectomy before balloon angioplasty and/or stenting is possible and a good alternative to thrombolysis.

  20. Load-bearing capacity of screw-retained CAD/CAM-produced titanium implant frameworks (I-Bridge®2) before and after cyclic mechanical loading

    PubMed Central

    DITTMER, Marc Philipp; NENSA, Moritz; STIESCH, Meike; KOHORST, Philipp

    2013-01-01

    Implant-supported screw-retained fixed dental prostheses (FDPs) produced by CAD/ CAM have been introduced in recent years for the rehabilitation of partial or total endentulous jaws. However, there is a lack of data about the long-term mechanical characteristics. Objective The aim of this study was to investigate the failure mode and the influence of extended cyclic mechanical loading on the load-bearing capacity of these frameworks. Material and Methods Ten five-unit FDP frameworks simulating a free-end situation in the mandibular jaw were manufactured according to the I-Bridge®2-concept (I-Bridge®2, Biomain AB, Helsingborg, Sweden) and each was screw-retained on three differently angulated Astra Tech implants (30º buccal angulation/0º angulation/30º lingual angulation). One half of the specimens was tested for static load-bearing capacity without any further treatment (control), whereas the other half underwent five million cycles of mechanical loading with 100 N as the upper load limit (test). All specimens were loaded until failure in a universal testing machine with an occlusal force applied at the pontics. Load-displacement curves were recorded and the failure mode was macro- and microscopically analyzed. The statistical analysis was performed using a t-test (p=0.05). Results All the specimens survived cyclic mechanical loading and no obvious failure could be observed. Due to the cyclic mechanical loading, the load-bearing capacity decreased from 8,496 N±196 N (control) to 7,592 N±901 N (test). The cyclic mechanical loading did not significantly influence the load-bearing capacity (p=0.060). The failure mode was almost identical in all specimens: large deformations of the framework at the implant connection area were obvious. Conclusion The load-bearing capacity of the I-Bridge®2 frameworks is much higher than the clinically relevant occlusal forces, even with considerably angulated implants. However, the performance under functional loading in vivo

  1. Neuromuscular dentistry: Occlusal diseases and posture.

    PubMed

    Khan, Mohd Toseef; Verma, Sanjeev Kumar; Maheshwari, Sandhya; Zahid, Syed Naved; Chaudhary, Prabhat K

    2013-01-01

    Neuromuscular dentistry has been a controversial topic in the field of dentistry and still remains debatable. The issue of good occlusion and sound health has been repeatedly discussed. Sometimes we get complains of sensitive teeth and sometimes of tired facial muscles on getting up in the morning. Owing to the intimate relation of masticatory apparatus with the cranium and cervico-scapular muscular system, the disorders in any system, draw attention from concerned clinicians involved in management, to develop an integrated treatment protocol for the suffering patients. There may be patients reporting to the dental clinics after an occlusal restoration or extraction, having pain in or around the temporomandibular joint, headache or neck pain. Although their esthetic demands must not be undermined during the course of treatment plan, whenever dental treatment of any sort is planned, occlusion/bite should be given prime importance. Very few dentist are able to diagnose the occlusal disease and of those who diagnose many people resort to aggressive treatment modalities. This paper aims to report the signs of occlusal disease, and discuss their association with TMDs and posture.

  2. Neuromuscular dentistry: Occlusal diseases and posture

    PubMed Central

    Khan, Mohd Toseef; Verma, Sanjeev Kumar; Maheshwari, Sandhya; Zahid, Syed Naved; Chaudhary, Prabhat K.

    2013-01-01

    Neuromuscular dentistry has been a controversial topic in the field of dentistry and still remains debatable. The issue of good occlusion and sound health has been repeatedly discussed. Sometimes we get complains of sensitive teeth and sometimes of tired facial muscles on getting up in the morning. Owing to the intimate relation of masticatory apparatus with the cranium and cervico-scapular muscular system, the disorders in any system, draw attention from concerned clinicians involved in management, to develop an integrated treatment protocol for the suffering patients. There may be patients reporting to the dental clinics after an occlusal restoration or extraction, having pain in or around the temporomandibular joint, headache or neck pain. Although their esthetic demands must not be undermined during the course of treatment plan, whenever dental treatment of any sort is planned, occlusion/bite should be given prime importance. Very few dentist are able to diagnose the occlusal disease and of those who diagnose many people resort to aggressive treatment modalities. This paper aims to report the signs of occlusal disease, and discuss their association with TMDs and posture. PMID:25737904

  3. Primary Stenting in Infrarenal Aortic Occlusive Disease

    SciTech Connect

    Nyman, Ulf; Uher, Petr; Lindh, Mats; Lindblad, Bengt; Ivancev, Krasnodar

    2000-03-15

    Purpose: To evaluate the results of primary stenting in aortic occlusive disease.Methods: Thirty patients underwent primary stenting of focal concentric (n = 2) and complex aortic stenoses (n = 19), and aortic or aorto-iliac occlusions (n = 9). Sixteen patients underwent endovascular outflow procedures, three of whom also had distal open surgical reconstructions. Median follow-up was 16 months (range 1-60 months).Results: Guidewire crossing of two aorto-biiliac occlusions failed, resulting in a 93% (28/30) technical success. Major complications included one access hematoma, one myocardial infarction, one death (recurrent thromboembolism) in a patient with widespread malignancy, and one fatal hemorrhage during thrombolysis of distal emboli from a recanalized occluded iliac artery. One patient did not improve his symptoms, resulting in a 1-month clinical success of 83% (25/30). Following restenting the 26 stented survivors changed their clinical limb status to +3 (n = 17) and +2 (n = 9). During follow-up one symptomatic aortic restenosis occurred and was successfully restented.Conclusions: Primary stenting of complex aortic stenoses and short occlusions is an attractive alternative to conventional surgery. Larger studies with longer follow-up and stratification of lesion morphology are warranted to define its role relative to balloon angioplasty. Stenting of aorto-biiliac occlusions is feasible but its role relative to bypass grafting remains to be defined.

  4. Occlusal variation in a rural Kentucky community.

    PubMed

    Corruccini, R S; Whitley, L D

    1981-03-01

    Some major theories concerning the etiology of malocclusion and its modern increase in frequency include genetic explanations, such as inbreeding, racial crossing, and accumulation of mutations, as well as such environmental causes as "habits," allergies, and caries causing reduced arch space of premature deciduous tooth loss. Reduction of masticatory stress resulting from modern urbanism is less often considered as an agent. Many examples of acquisition of gross malocclusion in aboriginal peoples immediately following dietary "modernization" contradict the genetic explanations. A rural population from central Kentucky presents several propitious social characteristics for epidemiologic study of occlusion. They have experienced almost no professional dental care, they are highly inbred (but less so during the last 30 years), and their diet included many difficult-to-chew foods until the recent introduction of industry to the area. Occlusion was evaluated according to the criteria of the Treatment Priority Index. The temporal change and correlates of occlusal variation were assessed on wax-bite impressions of thirty-four persons, informant dietary histories, and other information. The older inhabitants raised on more traditional diets show significantly better occlusion. Dietary consistency provides the most powerful explanation for the transition in occlusal variation, through it was not conclusive in these data.

  5. Time Management in Acute Vertebrobasilar Occlusion

    SciTech Connect

    Kamper, Lars; Mansour, Michael; Winkler, Sven B.; Kempkes, Udo; Haage, Patrick

    2009-03-15

    Acute vertebrobasilar occlusion (VBO) is associated with a high risk of stroke and death. Although local thrombolysis may achieve recanalization and improve outcome, mortality is still between 35% and 75%. However, without recanalization the chance of a good outcome is extremely poor, with mortality rates of 80-90%. Early treatment is a fundamental factor, but detailed studies of the exact time management of the diagnostic and interventional workflow are still lacking. Data on 18 patients were retrospectively evaluated. Time periods between symptom onset, admission to hospital, time of diagnosis, and beginning of intervention were correlated with postinterventional neurological status. The Glasgow Coma Scale and National Institute of Health Stroke Scale (NIHSS) were used to examine patients before and after local thrombolysis. Additionally, multivariate statistics were applied to reveal similarities between patients with neurological improvement. Primary recanalization was achieved in 77% of patients. The overall mortality was 55%. Major complications were intracranial hemorrhage and peripheral embolism. The time period from symptom onset to intervention showed a strong correlation with the postinterventional NIHSS as well as the patient's age, with the best results in a 4-h interval. Multivariate statistics revealed similarities among the patients. Evaluation of time management in acute VBO by multivariate statistics is a helpful tool for definition of similarities in this patient group. Similarly to the door-to-balloon time for acute coronary interventions, the chances for a good outcome depend on a short time interval between symptom onset and intervention. While the only manipulable time period starts with hospital admission, our results emphasize the necessity of efficient intrahospital workflow.

  6. Leuprolide acetate and central retinal vein occlusion.

    PubMed

    Federici, Thomas J

    2007-01-01

    A 63-year-old man suffered a central retinal vein occlusion 2 months after he began taking leuprolide acetate for prostate cancer. Despite control for possible systemic hypertension (126/90 mm Hg) and mild hypercholesterolemia (total cholesterol level =246 mg/dL [range: 16 to 200 mg/dL], high-density lipoprotein level =67 mg/dL [range: 40 to 59 mg/dL], and low-density lipoprotein level =144 mg/dL [range: 0 to 130 mg/dL]), progression of the venous occlusive disease occurred. Leuprolide acetate, which is associated with thromboembolic events and diffuse intravascular coagulation, may be implicated in central retinal vein occlusion.

  7. Acute arterial occlusion after total knee arthroplasty.

    PubMed

    Gregory, Patricia C; Rogic, Roselyn; Eddington, Carolyn

    2006-11-01

    There are a number of complications associated with total knee-joint arthroplasty. These include deep venous thromboses, peroneal palsy, infection, anemia, and Ogilvie's syndrome. An uncommon but potentially limb-threatening complication is acute arterial occlusion. Approximately 35 cases have been reported in the orthopedic literature. Prompt recognition and treatment intervention are the keys to successful outcome. We describe the case of one patient who had mild peroneal palsy and developed acute arterial occlusion 9 days postoperatively while on the inpatient rehabilitation service. Prompt aggressive management restored arterial circulation to the lower limb. Careful management of patients after total knee arthroplasty requires an understanding that arterial occlusion is a rare limb-threatening complication of surgery, but that it is treatable with prompt, deliberate management. Physiatrists should be aware that this condition exists in postoperative knee-joint arthroplasty patients. They should pay careful attention to any patient with a history of peripheral vascular disease or postoperative peroneal palsy.

  8. Cephalometric estimation of vertical dimension of occlusion.

    PubMed

    Orthlieb, J D; Laurent, M; Laplanche, O

    2000-09-01

    The literature does not establish a single proven method for determining lower facial height, which is called the Vertical Dimension of Occlusion (VDO), and the concept of a vertical comfort range is generally accepted. This study aimed to test the statistical significance of correlations of mandibular shape versus lower facial height in occlusion, using cephalometric measurements. Correlations for 505 consecutive healthy adults were calculated between angles that estimate the lower facial height and angles that estimate the mandibular shape. The mandibular angle (gonial) showed a higher coefficient of correlation (r = 0.691) than the inferior gonial angle. The dispersion remained large, i.e. r2 = 0.478. Cephalometric measurements, despite theirs imperfections, could help the practitioner to understand what the best course of treatment would be in order to obtain a lower facial height in occlusion showing a skeletal harmony with the mandibular shape.

  9. Occlusal plane determination using custom made broadrick occlusal plane analyser: a case control study.

    PubMed

    Manvi, Supriya; Miglani, Shaveta; Rajeswari, C L; Srivatsa, G; Arora, Sarvesh

    2012-01-01

    Proper occlusal plane is an essential consideration when multiple long span posterior restorations are designed. The determination of the occlusal plane can have a profound effect on the short and long term success of a restorative case. Purpose of Study. (1) To determine the appropriate occlusal curve for individual patients. (2) To compare the deviation of the clinical occlusal curve with the ideal ones. Materials and Methods. A total of 20 subjects were examined and study models were made of their maxillary and mandibular dentition. Inter-occlusal records were made and the casts were articulated in semiadjustable articulator. An ideal occlusal plane was created. The distance of the farthest cusp tip from the Broadrick curve was measured along the long axis of the tooth for each individual. Paired t-tests were used to compare the findings between subjects and controls. Results. A statistically significant difference P < 0.05 was found in the deviation from the Broadrick curve between patients who have lost posterior teeth and the control group who had a full dentition with no missing teeth. Conclusion. Proper utilization of the broadrick flag on a semi-adjustable articulator will allow for a correct determination of the occlusal plane.

  10. Antegrade Techniques for Chronic Total Occlusions

    PubMed Central

    Lim, Michael C.L.

    2015-01-01

    By convention, a total obstruction of the coronary artery with no flow at the occluded segment that has been present for at least 3 months is termed as chronic total occlusion or CTO. This is to be distinguished from a sudden occlusion of the coro-nary artery lumen by a thrombus during an acute myocardial infarction. Percutaneous coronary intervention (PCI) of CTO is increasingly being performed by interventional cardiologists with improved success rates. In this article, the focus will be on antegrade techniques that will assist the operator to maximise the success rates and to minimise the complications.

  11. The Effect of Bangerter Occlusion Foils on Blepharospasm and Hemifacial Spasm in Occlusion-Positive and Occlusion-Negative Patients

    PubMed Central

    Malhotra, Raman; Then, Siew-Yin; Richards, Alison; Cheek, Elizabeth

    2010-01-01

    Objective: To test the hypothesis that occlusion-positive (OP) patients with blepharospasm (BEB) or hemifacial spasm (HFS) will benefit from a Bangerter occlusion foil (BOF), compared to occlusion-negative (ON) patients. OP/ON was based on immediate improvement in spasm with placement of a hand in front of either eye. Design: Prospective non-randomised single-centre pilot study. Participants: Fifteen-patients (6 BEB, 9 HFS). Methods: Patients were identified as OP or ON and wore highest-density BOF tolerable over one spectacle lens for 1 month. Outcomes were assessed at 1 month. Main Outcome Measures: Validated quality-of-life questionnaire (CDQ-24), scores of blink-rate and spasm severity assessed by two observers from video-recordings. Results: OP group had mean improvement in all scores. There was no change or worsening of scores in the ON group. In both BEB and HFS, more OP patients reported subjective benefit from wearing a foil (2 of 4 BEB, and 2 of 2 HFS) compared to the ON group (0 of 2 BEB, and 1 of 7 HFS). Conclusion: OP patients with BEB and HFS are more likely to experience improvement in spasms from wearing a BOF compared to ON patients. The occlusion test should be considered on all patients with BEB or HFS. PMID:20148097

  12. Management of acute central retinal artery occlusion: Intravenous thrombolysis is feasible and safe.

    PubMed

    Préterre, Cécile; Godeneche, Gaelle; Vandamme, Xavier; Ronzière, Thomas; Lamy, Matthias; Breuilly, Christophe; Urbanczyk, Cédric; Wolff, Valérie; Lebranchu, Pierre; Sevin-Allouet, Mathieu; Guillon, Benoit

    2017-01-01

    Background Although acute central retinal artery occlusion is as a stroke in the carotid territory (retinal artery), its management remains controversial. The aim of this study was to assess the feasibility and safety of intravenous thrombolysis delivered within 6 h of central retinal artery occlusion in French stroke units. Methods We performed a retrospective analysis of patients treated with intravenous alteplase (recombinant tissue-plasminogen activator), based on stroke units thrombolysis registers from June 2005 to June 2015, and we selected those who had acute central retinal artery occlusion. The feasibility was assessed by the ratio of patients that had received intravenous alteplase within 6 h after central retinal artery occlusion onset among those who had been admitted to the same hospital for acute central retinal artery occlusion. All adverse events were documented. Results Thirty patients were included. Visual acuity before treatment was limited to "hand motion", or worse, in 90% of the cases. The mean onset-to-needle time was 273 min. The individuals treated with intravenous alteplase for central retinal artery occlusion represented 10.2% of all of the patients hospitalized for central retinal artery occlusion in 2013 and 2014. We observed one occurrence of major bleeding, a symptomatic intracerebral hemorrhage. Conclusion When applied early on, intravenous thrombolysis appears to be feasible and safe, provided that contraindications are given due consideration. Whether intravenous thrombolysis is more effective than conservative therapy remains to be determined. In order to conduct a well-designed prospective randomized control trial, an organized network should be in place.

  13. Posterior open occlusion management by registration of overlay removable partial denture: A clinical report

    PubMed Central

    Nosouhian, Saeid; Davoudi, Amin; Derhami, Mohammad

    2015-01-01

    This clinical report describes prosthetic rehabilitation of posterior open bite relationship in a patient with several missing teeth and skeletal Class III malocclusion. Primary diagnostic esthetic evaluations were performed by mounting casts in centric relation and estimating lost vertical dimension of occlusion. Exclusive treatments were designated by applying overlay removable partial denture with external attachment systems for higher retentions. PMID:26929544

  14. Causal assessment of dietary acid load and bone disease: a systematic review & meta-analysis applying Hill's epidemiologic criteria for causality

    PubMed Central

    2011-01-01

    Background Modern diets have been suggested to increase systemic acid load and net acid excretion. In response, alkaline diets and products are marketed to avoid or counteract this acid, help the body regulate its pH to prevent and cure disease. The objective of this systematic review was to evaluate causal relationships between dietary acid load and osteoporosis using Hill's criteria. Methods Systematic review and meta-analysis. We systematically searched published literature for randomized intervention trials, prospective cohort studies, and meta-analyses of the acid-ash or acid-base diet hypothesis with bone-related outcomes, in which the diet acid load was altered, or an alkaline diet or alkaline salts were provided, to healthy human adults. Cellular mechanism studies were also systematically examined. Results Fifty-five of 238 studies met the inclusion criteria: 22 randomized interventions, 2 meta-analyses, and 11 prospective observational studies of bone health outcomes including: urine calcium excretion, calcium balance or retention, changes of bone mineral density, or fractures, among healthy adults in which acid and/or alkaline intakes were manipulated or observed through foods or supplements; and 19 in vitro cell studies which examined the hypothesized mechanism. Urine calcium excretion rates were consistent with osteoporosis development; however calcium balance studies did not demonstrate loss of whole body calcium with higher net acid excretion. Several weaknesses regarding the acid-ash hypothesis were uncovered: No intervention studies provided direct evidence of osteoporosis progression (fragility fractures, or bone strength as measured using biopsy). The supporting prospective cohort studies were not controlled regarding important osteoporosis risk factors including: weight loss during follow-up, family history of osteoporosis, baseline bone mineral density, and estrogen status. No study revealed a biologic mechanism functioning at physiological p

  15. Occlusion, prosthodontic treatment, and temporomandibular disorders: a review.

    PubMed

    Hagag, G; Yoshida, K; Miura, H

    2000-03-01

    The purpose of this article is to review the literature on the relationship between occlusal discrepancies and temporomandibular disorders (TMD) and to summarize the guidelines of treating TMD by prosthetic rehabilitation. To date, the relationship between occlusal condition and TMD has not been confirmed, although there is a current trend toward making a weak correlation between occlusal interference and TMD. Furthermore, several types of occlusal discrepancies have been considered as variable features of the norm. But unstable occlusion in the intercuspal position may cause TMD. In cases of restored dentition, the problem is probably different and iatrogenic TMD are not rare. Namely, malformed occlusal surfaces, defects in anterior guidance, occlusal curvature, and vertical dimension may lead to some TMD trouble. According to these recent concepts the treatment modalities of TMD have been changed. Conservative treatments such as counseling, behavioral modification, physical therapy, pharmacotherapy, and interocclusal appliances should be the first choice, and treatments that lead to drastic changes of occlusion are not recommended.

  16. Management of Bilateral Carotid Occlusive Disease

    PubMed Central

    Jadhav, Ashutosh P.; Ducruet, Andrew F.; Jankowitz, Brian T.; Jovin, Tudor G.

    2016-01-01

    Background Symptomatic bilateral internal carotid occlusive disease is a rare but potentially devastating entity. Medical therapy alone is associated with high rates of mortality and recurrent stroke. The optimal management of this disease remains poorly understood. Methods A retrospective review of a prospectively maintained database was conducted for patients who presented with an acute stroke in the setting of bilateral carotid occlusive disease between May and October 2013. Results We identified 3 patients. The admission National Institutes of Health Stroke Scale score ranged from 4 to 7. All patients had small- to moderate-sized infarcts in the anterior circulation on presentation. Angiography confirmed bilateral internal carotid occlusions with collateral filling via the posterior communicating artery and retrograde filling via external carotid artery supply to the ophthalmic artery. All patients were initially managed with permissive hypertension and anticoagulation followed by carotid angioplasty and stenting. At 1-year follow-up, all patients demonstrated a modified Rankin scale score of 0-1. Conclusions Carotid stenting may be a safe and effective therapy for patients presenting with symptomatic bilateral carotid occlusions. PMID:27051405

  17. Infant Defensive Reactions to Visual Occlusion.

    ERIC Educational Resources Information Center

    Adamson, Lauren; Tronick, Edward

    This paper describes the initial organization of the infant's reaction to having his vision occluded by an opaque cloth; traces the development of this reaction over the first six months; and probes the role the occlusion of vision plays in provoking the reaction. Fifty videotaped sessions of infants during two conditions - eyes covered with an…

  18. Class II malocclusion occlusal severity description

    PubMed Central

    JANSON, Guilherme; SATHLER, Renata; FERNANDES, Thais Maria Freire; ZANDA, Marcelo; PINZAN, Arnaldo

    2010-01-01

    Objectives It is well known that the efficacy and the efficiency of a Class II malocclusion treatment are aspects closely related to the severity of the dental anteroposterior discrepancy. Even though, sample selection based on cephalometric variables without considering the severity of the occlusal anteroposterior discrepancy is still common in current papers. In some of them, when occlusal parameters are chosen, the severity is often neglected. The purpose of this study is to verify the importance given to the classification of Class II malocclusion, based on the criteria used for sample selection in a great number of papers published in the orthodontic journal with the highest impact factor. Material and Methods A search was performed in PubMed database for full-text research papers referencing Class II malocclusion in the history of the American Journal of Orthodontics and Dentofacial Orthopedics (AJO-DO). Results A total of 359 papers were retrieved, among which only 72 (20.06%) papers described the occlusal severity of the Class II malocclusion sample. In the other 287 (79.94%) papers that did not specify the anteroposterior discrepancy severity, description was considered to be crucial in 159 (55.40%) of them. Conclusions Omission in describing the occlusal severity demands a cautious interpretation of 44.29% of the papers retrieved in this study. PMID:20835576

  19. Object Occlusion Detection Using Automatic Camera Calibration for a Wide-Area Video Surveillance System.

    PubMed

    Jung, Jaehoon; Yoon, Inhye; Paik, Joonki

    2016-06-25

    This paper presents an object occlusion detection algorithm using object depth information that is estimated by automatic camera calibration. The object occlusion problem is a major factor to degrade the performance of object tracking and recognition. To detect an object occlusion, the proposed algorithm consists of three steps: (i) automatic camera calibration using both moving objects and a background structure; (ii) object depth estimation; and (iii) detection of occluded regions. The proposed algorithm estimates the depth of the object without extra sensors but with a generic red, green and blue (RGB) camera. As a result, the proposed algorithm can be applied to improve the performance of object tracking and object recognition algorithms for video surveillance systems.

  20. Occlusal concepts in full mouth rehabilitation: an overview.

    PubMed

    Tiwari, Bhawana; Ladha, Komal; Lalit, Aaruti; Dwarakananda Naik, B

    2014-12-01

    Restoration of occlusion in patients with severely worn dentition is a challenging situation as every case is unique in itself. There is great apprehension involved in reconstructing debilitated dentition due to widely divergent views concerning the choice of an appropriate occlusal scheme for successful full mouth rehabilitation. This article is an overview of the various occlusal concepts/philosophies in full mouth rehabilitation which will help the clinician select an appropriate occlusal scheme for an individual case.

  1. Endovascular occlusion of pulmonary arteriovenous malformations with the ArtVentive Endoluminal Occlusion System™

    PubMed Central

    Corvino, Fabio; Silvestre, Mattia; Cervo, Amedeo; Giurazza, Francesco; Corvino, Antonio; Maglione, Franco

    2016-01-01

    Pulmonary arteriovenous malformations (PAVMs) are vascular anomalies of the lung and carry the risk of cerebral thromboembolism, brain abscess, or pulmonary hemorrhage. We describe a 64-year-old male with hereditary hemorrhagic telangiectasia (Osler-Weber-Rendu syndrome) who presented with a five-year history of progressive effort dyspnea and a PAVM in the right upper lobe successfully treated by transcatheter embolization of feeding arteries using a new occlusion device, the ArtVentive Endoluminal Occlusion System™. PMID:27559714

  2. An appraisal on increasing the occlusal vertical dimension in full occlusal rehabilitation and its outcome.

    PubMed

    Gopi Chander, N; Venkat, R

    2011-06-01

    Increasing the occlusal vertical dimension for gaining sufficient restoration space in the management of severely worn dentition is being practiced. This contentious belief has lead to challenging thoughts regarding its effects on the Odonto-stomatognathic system. There are basic uncertainties and existing erroneous thoughts regarding the perception of increasing the occlusal vertical dimension. This manuscript will review the bite raising concepts and its outcome on the stomatognathic system.

  3. Occlusion as a causative factor in TMD. Scientific basis to occlusal therapy.

    PubMed

    Becker, I M

    1995-11-01

    There appears to be a pendulum swing toward large epidemiologic studies questioning the role of occlusion in dentistry. This article clearly demonstrates that significant scientific evidence exists on the side of occlusal causative factors. Clinicians need this current information to base practical decisions of treatment relative to both patients and those requiring restorative procedures. It further correctly clarifies that stress-related issues have an important role, along with other host-susceptibility altering factors.

  4. Buckling of vertical rod loaded by dead weight and tensile force subjected to its top end (applied to marine vertical oil pipelines—Risers)

    NASA Astrophysics Data System (ADS)

    Beyle, A. I.

    1997-07-01

    The problem of buckling of a vertical rod loaded by dead weight and tensile force to its top end was examined. Four variants for attachment of the top end of the rod upon clamping the bottom end were analyzed. The problem was solved by individual consideration of the stretched and compressed zones of the rod and their sewing together. Critical values of the axial force were obtained, which permit prevention of buckling of a long rod by the action of dead weight. Analysis permits selection of the required tension of vertical pipelines for deep-water oil drilling and demonstration of the advantages of using composites (especially, carbon-fiber-reinforced plastics) as materials for manufacture of the elements of such structures.

  5. Central composite design and genetic algorithm applied for the optimization of ultrasonic-assisted removal of malachite green by ZnO Nanorod-loaded activated carbon.

    PubMed

    Ghaedi, M; Azad, F Nasiri; Dashtian, K; Hajati, S; Goudarzi, A; Soylak, M

    2016-10-05

    Maximum malachite green (MG) adsorption onto ZnO Nanorod-loaded activated carbon (ZnO-NR-AC) was achieved following the optimization of conditions, while the mass transfer was accelerated by ultrasonic. The central composite design (CCD) and genetic algorithm (GA) were used to estimate the effect of individual variables and their mutual interactions on the MG adsorption as response and to optimize the adsorption process. The ZnO-NR-AC surface morphology and its properties were identified via FESEM, XRD and FTIR. The adsorption equilibrium isotherm and kinetic models investigation revealed the well fit of the experimental data to Langmuir isotherm and pseudo-second-order kinetic model, respectively. It was shown that a small amount of ZnO-NR-AC (with adsorption capacity of 20mgg(-1)) is sufficient for the rapid removal of high amount of MG dye in short time (3.99min).

  6. Central composite design and genetic algorithm applied for the optimization of ultrasonic-assisted removal of malachite green by ZnO Nanorod-loaded activated carbon

    NASA Astrophysics Data System (ADS)

    Ghaedi, M.; Azad, F. Nasiri; Dashtian, K.; Hajati, S.; Goudarzi, A.; Soylak, M.

    2016-10-01

    Maximum malachite green (MG) adsorption onto ZnO Nanorod-loaded activated carbon (ZnO-NR-AC) was achieved following the optimization of conditions, while the mass transfer was accelerated by ultrasonic. The central composite design (CCD) and genetic algorithm (GA) were used to estimate the effect of individual variables and their mutual interactions on the MG adsorption as response and to optimize the adsorption process. The ZnO-NR-AC surface morphology and its properties were identified via FESEM, XRD and FTIR. The adsorption equilibrium isotherm and kinetic models investigation revealed the well fit of the experimental data to Langmuir isotherm and pseudo-second-order kinetic model, respectively. It was shown that a small amount of ZnO-NR-AC (with adsorption capacity of 20 mg g- 1) is sufficient for the rapid removal of high amount of MG dye in short time (3.99 min).

  7. Occlusion handling in videos object tracking: A survey

    NASA Astrophysics Data System (ADS)

    Lee, B. Y.; Liew, L. H.; Cheah, W. S.; Wang, Y. C.

    2014-02-01

    Object tracking in video has been an active research for decades. This interest is motivated by numerous applications, such as surveillance, human-computer interaction, and sports event monitoring. Many challenges regarding tracking objects remain, this can arise due to abrupt object motion, changing appearance patterns of objects and the scene, non-rigid object structures and most significancly occlusion of tracked object (be it object-to-object or object-to-scene occlusions). Generally, occlusion in object tracking occurs under three situations: self-occlusion, inter-object occlusion by background scene structure. Self-occlusion most frequently arises while tracking articulated objects when one part of the object occludes another. Inter-object occlusion occurs when two objects being tracked occlude each other whereas occlusion by the background occurs when a structure in the background occludes the tracked objects. Typically, tracking methods handle occlusion by modelling the object motion using linear and non-linear dynamic models. The derived models will be used to continuously predicting the object location when a tracked object is occluded until the object reappears. Examples of these methods are Kalman filtering and Particle filtering trackers. Researchers have also utilised other features to resolved occlusion, for example, silhouette projections, colour histogram and optical flow. We will present some results from a previously conducted experiment when tracking single object using Kalman filter, Particle filter and Mean Shift trackers under various occlusion situations. We will also review various other occlusion handling methods that involved using multiple cameras. In a nutshell, the goal of this paper is to discuss in detail the problem of occlusion in object tracking and review the state of the art occlusion handling methods, classify them into different categories, and identify new trends. Moreover, we discuss the important issues related to occlusion

  8. Occlusion Handling in Videos Object Tracking: A Survey

    NASA Astrophysics Data System (ADS)

    Lee, B. Y.; Liew, L. H.; Cheah, W. S.; Wang, Y. C.

    2014-02-01

    Object tracking in video has been an active research since for decades. This interest is motivated by numerous applications, such as surveillance, human-computer interaction, and sports event monitoring. Many challenges related to tracking objects still remain, this can arise due to abrupt object motion, changing appearance patterns of objects and the scene, non-rigid object structures and most significant are occlusion of tracked object be it object-to-object or object-to-scene occlusions. Generally, occlusion in object tracking occur under three situations: self-occlusion, inter-object occlusion by background scene structure. Self-occlusion occurs most frequently while tracking articulated objects when one part of the object occludes another. Inter-object occlusion occurs when two objects being tracked occlude each other whereas occlusion by the background occurs when a structure in the background occludes the tracked objects. Typically, tracking methods handle occlusion by modelling the object motion using linear and non-linear dynamic models. The derived models will be used to continuously predicting the object location when a tracked object is occluded until the object reappears. Example of these method are Kalman filtering and Particle filtering trackers. Researchers have also utilised other features to resolved occlusion, for example, silhouette projections, colour histogram and optical flow. We will present some result from a previously conducted experiment when tracking single object using Kalman filter, Particle filter and Mean Shift trackers under various occlusion situation in this paper. We will also review various other occlusion handling methods that involved using multiple cameras. In a nutshell, the goal of this paper is to discuss in detail the problem of occlusion in object tracking and review the state of the art occlusion handling methods, classify them into different categories, and identify new trends. Moreover, we discuss the important

  9. Correction of the occlusal and functional sequelae of mandibular condyle fractures using orthodontic mini-implant molar intrusion.

    PubMed

    Cousley, Richard R J; Gibbons, Andrew J

    2014-09-01

    We report on the non-surgical management of an adult female whose bilateral mandibular condylar fractures had resulted in a clockwise (posterior) mandibular rotation, limitation of mandibular movements and increased occlusal loading on the molar teeth. She refused maxillary surgery and was treated with a minimally-invasive approach, involving orthodontic fixed appliances and mini-implant intrusion of the maxillary molar teeth. This provided both occlusal and functional improvements, including a significant increase in the inter-incisal distance, which were stable after one year of retention.

  10. 14 CFR 23.511 - Ground load; unsymmetrical loads on multiple-wheel units.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... coefficient of friction of 0.8 applied to the main gear and its supporting structure. (b) Unequal tire loads... CATEGORY AIRPLANES Structure Ground Loads § 23.511 Ground load; unsymmetrical loads on multiple-wheel...

  11. 14 CFR 23.511 - Ground load; unsymmetrical loads on multiple-wheel units.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... coefficient of friction of 0.8 applied to the main gear and its supporting structure. (b) Unequal tire loads... CATEGORY AIRPLANES Structure Ground Loads § 23.511 Ground load; unsymmetrical loads on multiple-wheel...

  12. 14 CFR 23.511 - Ground load; unsymmetrical loads on multiple-wheel units.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... coefficient of friction of 0.8 applied to the main gear and its supporting structure. (b) Unequal tire loads... CATEGORY AIRPLANES Structure Ground Loads § 23.511 Ground load; unsymmetrical loads on multiple-wheel...

  13. 14 CFR 23.511 - Ground load; unsymmetrical loads on multiple-wheel units.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... coefficient of friction of 0.8 applied to the main gear and its supporting structure. (b) Unequal tire loads... CATEGORY AIRPLANES Structure Ground Loads § 23.511 Ground load; unsymmetrical loads on multiple-wheel...

  14. 14 CFR 23.511 - Ground load; unsymmetrical loads on multiple-wheel units.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... coefficient of friction of 0.8 applied to the main gear and its supporting structure. (b) Unequal tire loads... CATEGORY AIRPLANES Structure Ground Loads § 23.511 Ground load; unsymmetrical loads on multiple-wheel...

  15. AnSBBR applied to the treatment of wastewater from a personal care industry: effect of organic load and fill time.

    PubMed

    de Oliveira, Daniela Sotirchos; Prinholato, Ana Claudia; Ratusznei, Suzana Maria; Rodrigues, José Alberto Domingues; Zaiat, Marcelo; Foresti, Eugênio

    2009-07-01

    The objective of this work was to study the technological feasibility of treating wastewater from a personal care industry (PCI-WW) in a mechanically stirred anaerobic sequencing batch biofilm reactor (AnSBBR) containing immobilized biomass on polyurethane foam. An assessment was made on how system efficiency and stability would be affected by: increasing organic load; supplementation of nutrients and alkalinity; and different feed strategies. The AnSBBR operated with 8-h cycles, stirring speed of 400 rpm, temperature of 30 degrees C, and treated with 2.0 L wastewater per cycle. First the efficiency and stability of the AnSBBR were studied when submitted to an organic loading rate (OLR) of 3.1-9.4 gCOD/(L d), and when the PCI-WW was supplemented with nutrients (sucrose, urea, trace metals) and alkalinity. The AnSBBR was shown to be robust and presented stability and removal efficiency exceeding 90%. At an OLR of 12.0 gCOD/(L d) efficiency became difficult to maintain due to the presence of commercial cleansers and disinfectants in the wastewater lots. In a subsequent stage the AnSBBR treated the wastewater supplemented with alkalinity, but with no nutrients at varying feed strategies and maintaining an OLR of approximately 9.0 gCOD/(L d). The first strategy consists of feeding 2.0 L of the influent batchwise [OLR of 9.4 gCOD/(L d)]. In the second 1.0 L of influent was fed-batchwise and an additional 1.0 L was fed fed-batchwise [OLR of 9.2 gCOD/(L d)], i.e., in relation to the first strategy the feed volume was maintained but supplied in different periods. In the third strategy 1.0 L of treated effluent was maintained in the reactor and 1.0 L of influent was fed fed-batchwise [OLR of 9.0 gCOD/(L d)], i.e., in relation to the first strategy the feed volume was different but the feed period was the same and the OLR was maintained by increasing the influent concentration. Comparison of the first and second strategies revealed that organic matter removal efficiency was

  16. Photoacoustic removal of occlusions from blood vessels

    DOEpatents

    Visuri, Steven R.; Da Silva, Luiz B.; Celliers, Peter M.; London, Richard A.; Maitland, IV, Duncan J.; Esch, Victor C.

    2002-01-01

    Partial or total occlusions of fluid passages within the human body are removed by positioning an array of optical fibers in the passage and directing treatment radiation pulses along the fibers, one at a time, to generate a shock wave and hydrodynamics flows that strike and emulsify the occlusions. A preferred application is the removal of blood clots (thrombin and embolic) from small cerebral vessels to reverse the effects of an ischemic stroke. The operating parameters and techniques are chosen to minimize the amount of heating of the fragile cerebral vessel walls occurring during this photo acoustic treatment. One such technique is the optical monitoring of the existence of hydrodynamics flow generating vapor bubbles when they are expected to occur and stopping the heat generating pulses propagated along an optical fiber that is not generating such bubbles.

  17. The unilateral chewing phenomenon, occlusion, and TMD.

    PubMed

    Reinhardt, Rotraut; Tremel, Timm; Wehrbein, Heiner; Reinhardt, Wilfried

    2006-07-01

    The aim of this study was to evaluate the role of occlusal factors to determine the extent of their role in temporomandibular disorders (TMD). Two groups were selected: a patient group (I) of 100 patients with TMD problems (pain and clicking) and a control group (II) of 100. Each individual had to have 28 permanent teeth. A clinical evaluation was conducted and the models were evaluated according to the criteria of the Angle Classes and the Reinhardt Index, with the number of permanent teeth (A), the number of the correctly (R) and the number of incorrectly (F) related antagonist pairs of teeth. The individuals had to observe the preference of their chewing side. The results of this investigation revealed: the number of F can be used as an occlusal indicator for possible functional disorders (p=0.041). Individuals with one chewing side have more signs and symptoms of TMD (p<6.22x10(-9)).

  18. Complications of Recanalization of Chronic Total Occlusion

    PubMed Central

    Kalyanasundaram, Arun; Lombardi, William L.

    2015-01-01

    Percutaneous Coronary Intervention (PCI) of Chronic Total Occlusions (CTO) is an accepted revascularization procedure. These complex procedures carry with them certain risks and potential complications. Complications of PCI such as contrast induced renal dysfunction, radiation, etc, assume more relevance given the length and complexity of these procedures. Further, certain complications such as donor vessel injury, foreign body entrapment are unique to CTO PCI. A thorough understanding of the potential complications is important in mitigating risk during these complex procedures.

  19. [Stability of orthodontic treatment of occlusal asymmetry].

    PubMed

    Burstone, C; Filleul, M P; Pigeot, V

    2000-09-01

    A common finding in orthodontic patients is asymmetric occlusion. These asymmetries can be dental, skeletal, or functional in origin. Since many patients have typical posterior overjet the use of Class II-Class III and anterior crisscross elastics are contra-indicated. Even in skeletal discrepancies axial inclination compensation can produce relatively normal overjet in the arch. The best strategy for non-extraction therapy is to move teeth around the arch rather than an en-masse movement of the entire arch. A number of methods for unilateral distalization are discussed. Midline correction requires the determination of facial, apical base, and posterior midpoints. Differential mechanics between patients with apical base discrepancies and no apical base is presented. Although intermaxillary elastics can be indicated the undesirable effects of eruption and frontal occlusal plane tilt should be considered. Advantages in control and ease of occlusal correction rest with intra-arch mechanics. The use of intermaxillary elastics for the correction subdivision cases can lead to instability and or mandibular shifts.

  20. Dental Occlusion and Ophthalmology: A Literature Review

    PubMed Central

    Marchili, Nicola; Ortu, Eleonora; Pietropaoli, Davide; Cattaneo, Ruggero; Monaco, Annalisa

    2016-01-01

    Stomatognathic system is strictly correlated to other anatomical regions; many studies investigated relationship between temporomandibular joint and posture, several articles describe cranio-facial pain from dental causes, such as trigger points. Until now less interest has been given to connections between dental occlusion and ophthalmology, even if they are important and involving. Clinical experience in dental practice claims that mandibular latero-deviation is connected both to eye dominance and to defects of ocular convergence. The trigeminal nerve is the largest and most complex of the twelve cranial nerves. The trigeminal system represents the connection between somitic structures and those derived from the branchial arches, collecting the proprioception from both somitic structures and oculomotor muscles. The intermedius nucleus of the medulla is a small perihypoglossal brainstem nucleus, which acts to integrate information from the head and neck and relays it on to the nucleus of the solitary tract where autonomic responses are generated. This intriguing neurophysiological web led our research group to investigate anatomical and functional associations between dental occlusion and vision. In conclusion, nervous system and functional pathways strictly connect vision and dental occlusion, and in the future both dentists and oculists should be more and more aware of this correlation for a better diagnosis and therapy. PMID:27733873

  1. Influence of occlusal splint on competitive athletes performances

    PubMed Central

    D’Ermes, Vittorio; Basile, Mario; Rampello, Alessandro; Di Paolo, Carlo

    2012-01-01

    Summary The purpose of this study was to evaluate the influence of an orthopedic oral device on the performance of competitive athletes. Seven athletes from different sports have been examined during athletic tests with and without an oral device. The athletes were examined by two calibrated gnathologic operators and with specific radiography. All of the subjects were submitted to a postural exam on an electronic platform with and without the oral device applied. All subjects underwent objective tests, performed by federal trainers in specialized centers, to evaluate the athletic performance with and without the occlusal splint. The results showed an improvement of all the tests carried out. Our findings lead us to believe that the use of a costumed oral device, it is able to optimize neuro-muscular coordination and to improve the competitive performance of athletes, while the muscular strength not respond significantly. PMID:23386932

  2. Predicting fecal sources in waters with diverse pollution loads using general and molecular host-specific indicators and applying machine learning methods.

    PubMed

    Casanovas-Massana, Arnau; Gómez-Doñate, Marta; Sánchez, David; Belanche-Muñoz, Lluís A; Muniesa, Maite; Blanch, Anicet R

    2015-03-15

    In this study we use a machine learning software (Ichnaea) to generate predictive models for water samples with different concentrations of fecal contamination (point source, moderate and low). We applied several MST methods (host-specific Bacteroides phages, mitochondrial DNA genetic markers, Bifidobacterium adolescentis and Bifidobacterium dentium markers, and bifidobacterial host-specific qPCR), and general indicators (Escherichia coli, enterococci and somatic coliphages) to evaluate the source of contamination in the samples. The results provided data to the Ichnaea software, that evaluated the performance of each method in the different scenarios and determined the source of the contamination. Almost all MST methods in this study determined correctly the origin of fecal contamination at point source and in moderate concentration samples. When the dilution of the fecal pollution increased (below 3 log10 CFU E. coli/100 ml) some of these indicators (bifidobacterial host-specific qPCR, some mitochondrial markers or B. dentium marker) were not suitable because their concentrations decreased below the detection limit. Using the data from source point samples, the software Ichnaea produced models for waters with low levels of fecal pollution. These models included some MST methods, on the basis of their best performance, that were used to determine the source of pollution in this area. Regardless the methods selected, that could vary depending on the scenario, inductive machine learning methods are a promising tool in MST studies and may represent a leap forward in solving MST cases.

  3. Binocular Rivalry Measured 2 Hours After Occlusion Therapy Predicts the Recovery Rate of the Amblyopic Eye in Anisometropic Children

    PubMed Central

    Lunghi, Claudia; Morrone, Maria Concetta; Secci, Jacopo; Caputo, Roberto

    2016-01-01

    Purpose Recent studies on adults have shown that short-term monocular deprivation boosts the deprived eye signal in binocular rivalry, reflecting homeostatic plasticity. Here we investigate whether homeostatic plasticity is present also during occlusion therapy for moderate amblyopia. Methods Binocular rivalry and visual acuity (using Snellen charts for children) were measured in 10 children (mean age 6.2 ± 1 years) with moderate anisometropic amblyopia before the beginning of treatment and at four intervals during occlusion therapy (2 hours, 1, 2, and 5 months). Visual stimuli were orthogonal gratings presented dichoptically through ferromagnetic goggles and children reported verbally visual rivalrous perception. Bangerter filters were applied on the spectacle lens over the best eye for occlusion therapy. Results Two hours of occlusion therapy increased the nonamblyopic eye predominance over the amblyopic eye compared with pretreatment measurements, consistent with the results in adults. The boost of the nonamblyopic eye was still present after 1 month of treatment, steadily decreasing afterward to reach pretreatment levels after 2 months of continuous occlusion. Across subjects, the increase in nonamblyopic eye predominance observed after 2 hours of occlusion correlated (rho = −0.65, P = 0.04) with the visual acuity improvement of the amblyopic eye measured after 2 months of treatment. Conclusions Homeostatic plasticity operates during occlusion therapy for moderate amblyopia and the increase in nonamblyopic eye dominance observed at the beginning of treatment correlates with the amblyopic eye recovery rate. These results suggest that binocular rivalry might be used to monitor visual cortical plasticity during occlusion therapy, although further investigations on larger clinical populations are needed to validate the predictive power of the technique. PMID:27046118

  4. Association between dental implants in the posterior region and traumatic occlusion in the adjacent premolars: a long-term follow-up clinical and radiographic analysis

    PubMed Central

    2016-01-01

    Purpose The aim of this retrospective study was to determine the association between dental implants in the posterior region and traumatic occlusion in the adjacent premolars, using data collected during from 2002 to 2015. Methods Traumatic occlusion in the adjacent premolars was assessed by examining clinical parameters (bleeding on probing, probing pocket depth, fremitus, and tooth mobility) and radiographic parameters (loss of supporting bone and widening of the periodontal ligament space) over a mean follow-up of 5 years. Clinical factors (gender, age, implant type, maxillary or mandibular position, opposing teeth, and duration of functional loading) were evaluated statistically in order to characterize the relationship between implants in the posterior region and traumatic occlusion in the adjacent premolars. Results The study inclusion criteria were met by 283 patients, who had received 347 implants in the posterior region. The incidence of traumatic occlusion in the adjacent premolars was significantly higher for splinted implants (P=0.004), implants in the maxillary region (P<0.001), and when implants were present in the opposing teeth (P<0.001). The other clinical factors of gender, age, and duration of functional loading were not significantly associated with traumatic occlusion. Conclusions This study found that the risk of traumatic occlusion in the adjacent premolars increased when splinted implants were placed in the maxillary molar region and when the teeth opposing an implant also contained implants. PMID:28050317

  5. Assessment of the effect of two occlusal concepts for implant-supported fixed prostheses by finite element analysis in patients with bruxism.

    PubMed

    Göre, Evrim; Evlioğlu, Gülümser

    2014-02-01

    The aim of this study was to evaluate the effects of bruxing forces on implants configured under 2 different occlusal schemes by dynamic finite element analysis. A main model consisting of a 5-unit fixed partial denture supported by 3 implants was simulated with bone, implants, and superstructures. All calculations were made individually for each component, namely porcelain crowns, abutments, abutment screws, implants, and bone. Maximum stresses were found in the group-function occlusion. Group-function loading may result excess stresses on the components compared with canine-guidance loading. According to the results of this study, use of canine guidance is encouraged in bruxers with implant-supported prostheses.

  6. Thrombolytic therapy for central venous catheter occlusion

    PubMed Central

    Baskin, Jacquelyn L.; Reiss, Ulrike; Wilimas, Judith A.; Metzger, Monika L.; Ribeiro, Raul C.; Pui, Ching-Hon; Howard, Scott C.

    2012-01-01

    Background Long-term central venous catheters have improved the quality of care for patients with chronic illnesses, but are complicated by obstructions which can result in delay of treatment or catheter removal. Design and Methods This paper reviews thrombolytic treatment for catheter obstruction. Literature from Medline searches using the terms “central venous catheter”, “central venous access device” OR “central venous line” associated with the terms “obstruction”, “occlusion” OR “thrombolytic” was reviewed. Efficacy of thrombolytic therapy, central venous catheter clearance rates and time to clearance were assessed. Results Alteplase, one of the current therapies, clears 52% of obstructed catheters within 30 min with 86% overall clearance (after 2 doses, when necessary). However, newer medications may have higher efficacy or shorter time to clearance. Reteplase cleared 67–74% within 30–40 min and 95% of catheters overall. Occlusions were resolved in 70 and 83% of patients with one and 2 doses of tenecteplase, respectively. Recombinant urokinase cleared 60% of catheters at 30 min and 73% overall. Alfimeprase demonstrated rapid catheter clearance with resolution in 40% of subjects within 5 min, 60% within 30 min, and 80% within 2 h. Additionally, urokinase prophylaxis decreased the incidence of catheter occlusions from 16–68% in the control group to 4–23% in the treatment group; in some studies, rates of catheter infections were also decreased in the urokinase group. Conclusions Thrombolytic agents successfully clear central venous catheter occlusions in most cases. Newer agents may act more rapidly and effectively than currently utilized therapies, but randomized studies with direct comparisons of these agents are needed to determine optimal management for catheter obstruction. PMID:22180420

  7. The acute response of practical occlusion in the knee extensors.

    PubMed

    Loenneke, Jeremy P; Kearney, Monica L; Thrower, Austin D; Collins, Sean; Pujol, Thomas J

    2010-10-01

    Training at low intensities with moderate vascular occlusion results in increased muscle hypertrophy, strength, and endurance. Elastic knee wraps, applied to the proximal portion of the target muscle, might elicit a stimulus similar to the KAATSU Master Apparatus. The purpose of this study was to test the hypothesis that intermittently occluding the leg extensors with elastic knee wraps would increase whole-blood lactate (WBL) over control (CON). Twelve healthy men and women participated in this study (age 21.2 ± 0.35 years, height 168.9 ± 2.60 cm, and body mass 71.2 ± 4.16 kg). One repetition maximum (1RM) testing for the leg extensors was performed on a leg extension machine for the first trial, followed by occlusion (OCC) and CON trials. Four sets of leg extension exercise (30-15-15-15) were completed with 150-second rest between sets at 30% 1RM. Whole-blood lactate, heart rate (HR), and ratings of perceived exertion (RPEs) were measured after every set of exercise and 3 minutes postexercise. Data were analyzed using repeated-measures analysis of variance with statistical significance set at p ≤ 0.05. Whole-blood lactate increased in response to exercise (p = 0.01) but was not different between groups (OCC 6.28 ± 0.66 vs. CON 5.35 ± 0.36 mmol·L, p = 0.051). Heart rate (OCC 128.86 ± 4.37 vs. CON 119.72 ± 4.10 b·min⁻¹) was higher with OCC from sets 2-4 (p ≤ 0.03), with no difference 3 minutes postexercise (p = 0.29). Rating of perceived exertion was higher with OCC after every set (OCC 15.10 ± 0.31 vs. CON 12.16 ± 0.50, p = 0.01). In conclusion, no differences exist for WBL between groups, although there was a trend for higher levels with OCC. The current protocol for practical occlusion did not significantly increase metabolic stress more than normal low-intensity exercise. This study does not support the use of knee wraps as a mode of blood-flow restriction.

  8. Dental occlusion and periodontal disease: what is the real relationship?

    PubMed

    Bhola, Monish; Cabanilla, Leyvee; Kolhatkar, Shilpa

    2008-12-01

    ABSTRACT The role of occlusion in periodontal disease has always been a challenging topic. A good understanding of the current status of the relationship of occlusion and periodontitis is of paramount importance in order for dental clinicians to provide adequate and comprehensive periodontal treatment in patients presenting with traumatic occlusion. This article reviews the literature regarding the relationship between occlusion and periodontitis and presents recommendations for clinical practice based on available evidence. Clinical cases illustrating the complexity of this relationship and their management are presented.

  9. A simplified technique for fabricating esthetic cast metal occlusal surfaces for dentures.

    PubMed

    Krantz, W A; Ivanhoe, J R; Adrian, E D

    1990-06-01

    This article describes a simplified method for making esthetic cast metal occlusal surfaces. Monoplane posterior acrylic resin block teeth, cast in a nickel-chrome alloy, are coated with silane and an esthetic composite resin veneer is applied to the buccal surface. These veneered posterior metal teeth are incorporated in the wax setup and the dentures are processed and finished. The dentist's routine technique for delivering dentures to the patient can be followed.

  10. Common Carotid Artery Occlusion: A Case Series

    PubMed Central

    Bajkó, Zoltán; Bălaşa, Rodica; Moţăţăianu, Anca; Maier, Smaranda; Chebuţ, Octavia Claudia; Szatmári, Szabolcs

    2013-01-01

    Subjects and Methods. We analysed 5000 cerebrovascular ultrasound records. A total of 0.4% of the patients had common carotid artery occlusion (CCAO). Results. The mean age was 59.8 ± 14.2 years, and the male/female ratio was 2.33. The most frequent risk factors were hypertension, ischaemic heart disease, dyslipidemia, diabetes mellitus, and smoking. Right-sided and left-sided CCAO occurred in 65% and 30% of the cases, respectively, and bilateral occlusion was detected in one case (5%). Patent bifurcation was observed in 10 cases of CCAO in which the anterograde flow in the ICA was maintained from the external carotid artery with reversed flow. In two of the cases, the occluded CCA was hypoplastic. The aetiology of CCAO in the majority of cases was the atherosclerosis (15 cases). The male/female ratio was higher in the patients with occluded distal vessels, and the short-term outcome was poorer. Only two cases from this series underwent revascularisation surgery. Spontaneous recanalisation was observed in one case. Conclusions. The most frequent cause of CCAO was atherosclerosis. The outcome is improved in the cases with patent distal vessels, and spontaneous recanalisation is possible. Treatment methods have not been standardised. Surgical revascularisation is possible in cases of patent distal vessels, but the indications are debatable. PMID:24167740

  11. The occlusal appliance effect on myofascial pain.

    PubMed

    Villalón, Pablo; Arzola, Juan Francisco; Valdivia, José; Fresno, María Javiera; Santander, Hugo; Gutiérrez, Mario Felipe; Miralles, Rodolfo

    2013-04-01

    There are limited studies about the effects of occlusal appliance (OA) after three months of use. This study aimed to compare myofascial pain (MP) according to RDC/TMD, craniocervical relationships (CR) and masseter and temporalis bilateral electromyographic (EMG) activity, before and after three months of occlusal appliance use. Nineteen patients participated in this study. Cephalometric and RDC/TMD diagnostics were performed previously (baseline) and at the end of the study period (three months). EMG recordings at clinical mandibular rest position (MRP), during swallowing of saliva (SW) and during maximum voluntary clenching (MVC) were performed as follows: after one hour of use of an OA; after three months of using the OA for a minimum of 16 hours each day; and immediately after removal from the mouth. MP was relieved in all patients at the end of the study period. CR did not change significantly between baseline and after removal of the OA at the end of the study period. EMG activity during MRP, SW, and MVC decreased in both muscles after one hour using the OA and maintained the same level for the three-month period. When comparing baseline versus final EMG activity without OA, a significant decrease was only observed in the masseter muscle. The results observed in the present study are relevant to clinicians because they imply that the therapeutic effect of OA does not significantly affect the homeostasis of the craniocervical system.

  12. Numerical analysis of human dental occlusal contact

    NASA Astrophysics Data System (ADS)

    Bastos, F. S.; Las Casas, E. B.; Godoy, G. C. D.; Meireles, A. B.

    2010-06-01

    The purpose of this study was to obtain real contact areas, forces, and pressures acting on human dental enamel as a function of the nominal pressure during dental occlusal contact. The described development consisted of three steps: characterization of the surface roughness by 3D contact profilometry test, finite element analysis of micro responses for each pair of main asperities in contact, and homogenization of macro responses using an assumed probability density function. The inelastic deformation of enamel was considered, adjusting the stress-strain relationship of sound enamel to that obtained from instrumented indentation tests conducted with spherical tip. A mechanical part of the static friction coefficient was estimated as the ratio between tangential and normal components of the overall resistive force, resulting in μd = 0.057. Less than 1% of contact pairs reached the yield stress of enamel, indicating that the occlusal contact is essentially elastic. The micro-models indicated an average hardness of 6.25GPa, and the homogenized result for macroscopic interface was around 9GPa. Further refinements of the methodology and verification using experimental data can provide a better understanding of processes related to contact, friction and wear of human tooth enamel.

  13. Optimal management of infrainguinal arterial occlusive disease

    PubMed Central

    Pennywell, David J; Tan, Tze-Woei; Zhang, Wayne W

    2014-01-01

    Peripheral arterial occlusive disease is becoming a major health problem in Western societies as the population continues to age. In addition to risk of limb loss, the complexity of the disease is magnified by its intimate association with medical comorbidity, especially cardiovascular and cerebrovascular disease. Risk factor modification and antiplatelet therapy are essential to improve long-term survival. Surgical intervention is indicated for intermittent claudication when a patient’s quality of life remains unacceptable after a trial of conservative therapy. Open reconstruction and endovascular revascularization are cornerstone for limb salvage in patients with critical limb ischemia. Recent advances in catheter-based technology have made endovascular intervention the preferred treatment approach for infrainguinal disease in many cases. Nevertheless, lower extremity bypass remains an important treatment strategy, especially for reasonable risk patients with a suitable bypass conduit. In this review, we present a summary of current knowledge about peripheral arterial disease followed by a review of current, evidence-based medical and surgical therapy for infrainguinal arterial occlusive disease. PMID:25368519

  14. Computerized occlusal analysis: correlation with occlusal indexes to assess the outcome of orthodontic treatment or the severity of malocculusion

    PubMed Central

    Lee, Jin-Woo

    2016-01-01

    Objective The aims of our study were to verify the validity of the T-Scan III system (Tekscan) as an objective occlusal evaluation tool, and to assess the differences between two occlusal indexes-the peer assessment rating (PAR) index and the American Board of Orthodontics objective grading system (OGS)-by comparing the scores derived from the T-Scan III system with the two occlusal indexes and analyzing the correlations between them. Methods The final study sample included 48 adult volunteers (39 men and 9 women, mean age 24.14 ± 3.16 years), after excluding 29 volunteers whose occlusion could not be evaluated by the T-Scan III system due to severe skeletal or occlusal problems. PAR index and OGS scores were assessed using dental study models, and measurements of centric occlusion, protrusive movement, and lateral excursion movement were obtained via the T-Scan III system. The results were analyzed to determine correlations. Results Occlusal analysis by the T-Scan III system was clinically reliable (p < 0.05), and the PAR index and OGS scores were significantly correlated with several measurements obtained with the T-Scan III system (p < 0.05). Conclusions The T-Scan III system is a quantitative and reliable method for occlusal evaluation, and represents a potential substitute for occlusal indexes. Compared to the PAR index, the OGS scores of more variables were significantly correlated with the T-Scan measurements. PMID:26877980

  15. Intercostal muscle motor behavior during tracheal occlusion conditioning in conscious rats

    PubMed Central

    Jaiswal, Poonam B.

    2016-01-01

    A respiratory load compensation response is characterized by increases in activation of primary respiratory muscles and/or recruitment of accessory respiratory muscles. The contribution of the external intercostal (EI) muscles, which are a primary respiratory muscle group, during normal and loaded breathing remains poorly understood in conscious animals. Consciousness has a significant role on modulation of respiratory activity, as it is required for the integration of behavioral respiratory responses and voluntary control of breathing. Studies of respiratory load compensation have been predominantly focused in anesthetized animals, which make their comparison to conscious load compensation responses challenging. Using our established model of intrinsic transient tracheal occlusions (ITTO), our aim was to evaluate the motor behavior of EI muscles during normal and loaded breathing in conscious rats. We hypothesized that 1) conscious rats exposed to ITTO will recruit the EI muscles with an increased electromyogram (EMG) activation and 2) repeated ITTO for 10 days would potentiate the baseline EMG activity of this muscle in conscious rats. Our results demonstrate that conscious rats exposed to ITTO respond by recruiting the EI muscle with a significantly increased EMG activation. This response to occlusion remained consistent over the 10-day experimental period with little or no effect of repeated ITTO exposure on the baseline ∫EI EMG amplitude activity. The pattern of activation of the EI muscle in response to an ITTO is discussed in detail. The results from the present study demonstrate the importance of EI muscles during unloaded breathing and respiratory load compensation in conscious rats. PMID:26823339

  16. Multi-scale Visualization of Molecular Architecture Using Real-Time Ambient Occlusion in Sculptor

    PubMed Central

    Wahle, Manuel; Wriggers, Willy

    2015-01-01

    The modeling of large biomolecular assemblies relies on an efficient rendering of their hierarchical architecture across a wide range of spatial level of detail. We describe a paradigm shift currently under way in computer graphics towards the use of more realistic global illumination models, and we apply the so-called ambient occlusion approach to our open-source multi-scale modeling program, Sculptor. While there are many other higher quality global illumination approaches going all the way up to full GPU-accelerated ray tracing, they do not provide size-specificity of the features they shade. Ambient occlusion is an aspect of global lighting that offers great visual benefits and powerful user customization. By estimating how other molecular shape features affect the reception of light at some surface point, it effectively simulates indirect shadowing. This effect occurs between molecular surfaces that are close to each other, or in pockets such as protein or ligand binding sites. By adding ambient occlusion, large macromolecular systems look much more natural, and the perception of characteristic surface features is strongly enhanced. In this work, we present a real-time implementation of screen space ambient occlusion that delivers realistic cues about tunable spatial scale characteristics of macromolecular architecture. Heretofore, the visualization of large biomolecular systems, comprising e.g. hundreds of thousands of atoms or Mega-Dalton size electron microscopy maps, did not take into account the length scales of interest or the spatial resolution of the data. Our approach has been uniquely customized with shading that is tuned for pockets and cavities of a user-defined size, making it useful for visualizing molecular features at multiple scales of interest. This is a feature that none of the conventional ambient occlusion approaches provide. Actual Sculptor screen shots illustrate how our implementation supports the size-dependent rendering of molecular

  17. Guide wire extension for shape memory polymer occlusion removal devices

    DOEpatents

    Maitland, Duncan J.; Small, IV, Ward; Hartman, Jonathan

    2009-11-03

    A flexible extension for a shape memory polymer occlusion removal device. A shape memory polymer instrument is transported through a vessel via a catheter. A flexible elongated unit is operatively connected to the distal end of the shape memory polymer instrument to enhance maneuverability through tortuous paths en route to the occlusion.

  18. Sharp Recanalization for Chronic Left Iliac Vein Occlusion

    SciTech Connect

    Ito, Nobutake Isfort, Peter; Penzkofer, Tobias; Grommes, Jochen; Greiner, Andreas; Mahnken, Andreas

    2012-08-15

    Endovascular treatment has emerged as a first-line treatment for venous occlusions, but is sometimes challenging with conventional approaches. This article describes a helpful technique using a Roesch-Uchida needle to cross a chronic occlusion of the iliac vein when conventional techniques have failed.

  19. Occlusion and functional disorders of the masticatory system.

    PubMed

    Okeson, J P

    1995-04-01

    Understanding the relationship between occlusion and functional disorders of the masticatory system is no easy task. This article explores the static, functional, and dynamic relationships of the occlusal condition to the signs and symptoms of masticatory dysfunction. Some possible relationships are discussed.

  20. 21 CFR 870.2890 - Vessel occlusion transducer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ..., sound, and ultrasonic transducers. (b) Classification. Class II (performance standards). ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Vessel occlusion transducer. 870.2890 Section 870... transducer. (a) Identification. A vessel occlusion transducer is a device used to provide an...

  1. 21 CFR 870.2890 - Vessel occlusion transducer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ..., sound, and ultrasonic transducers. (b) Classification. Class II (performance standards). ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Vessel occlusion transducer. 870.2890 Section 870... transducer. (a) Identification. A vessel occlusion transducer is a device used to provide an...

  2. Effect of glove occlusion on the skin barrier.

    PubMed

    Tiedemann, Daniel; Clausen, Maja Lisa; John, Swen Malthe; Angelova-Fischer, Irena; Kezic, Sanja; Agner, Tove

    2016-01-01

    Wet work tasks are the most common exposures leading to occupational irritant contact dermatitis. Use of liquid-proof gloves is recommended when performing wet work, however, gloves may also contribute to impairment of the skin barrier and development of irritant contact dermatitis. The aim of this study is to review the literature on the effects of glove occlusion on skin barrier function. The PubMed database was searched up to 1 February 2015 for articles on the association between glove occlusion and skin barrier function, including human studies only and in English. Only experimental studies including assessment of the skin barrier function were included in the data analysis. Thirteen articles were identified, 8 with focus on occlusion alone, 7 with focus on occlusion in combination with irritant exposure (some overlapping), and 2 field studies. In conclusion, data from the literature showed that the negative effect of occlusion in itself is limited, and that only extensive and long-term occlusion will cause barrier impairment. However, studies investigating combined effect of occlusion and exposure to soaps/detergents indicate that occlusion significantly enhances the skin barrier damage caused by detergents/soaps in a dose-response fashion.

  3. 21 CFR 878.4020 - Occlusive wound dressing.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Occlusive wound dressing. 878.4020 Section 878.4020 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4020 Occlusive wound...

  4. 21 CFR 878.4020 - Occlusive wound dressing.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Occlusive wound dressing. 878.4020 Section 878.4020 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4020 Occlusive wound...

  5. 21 CFR 878.4020 - Occlusive wound dressing.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Occlusive wound dressing. 878.4020 Section 878.4020 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4020 Occlusive wound...

  6. 21 CFR 878.4020 - Occlusive wound dressing.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Occlusive wound dressing. 878.4020 Section 878.4020 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4020 Occlusive wound...

  7. 21 CFR 878.4020 - Occlusive wound dressing.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Occlusive wound dressing. 878.4020 Section 878.4020 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4020 Occlusive wound...

  8. Collateral Circulation in Chronic Total Occlusions - an interventional perspective.

    PubMed

    Choo, Gim-Hooi

    2015-09-09

    Human coronary collaterals are inter-coronary communications that are believed to be present from birth. In the presence of chronic total occlusions, recruitment of flow via these collateral anastomoses to the arterial segment distal to occlusion provide an alternative source of blood flow to the myocardial segment at risk. This mitigates the ischemic injury. Clinical outcome of coronary occlusion ie. severity of myocardial infarction/ischemia, impairment of cardiac function and possibly survival depends not only on the acuity of the occlusion, extent of jeopardized myocardium, duration of ischemia but also to the adequacy of collateral circulation. Adequacy of collateral circulation can be assessed by various methods. These coronary collateral channels have been used successfully as a retrograde access route for percutaneous recanalization of chronic total occlusions. Factors that promote angiogenesis and further collateral remodeling ie. arteriogenesis have been identified. Promotion of collateral growth as a therapeutic target in patients with no suitable revascularization option is an exciting proposal.

  9. Cilio-retinal arterial circulation in central retinal vein occlusion.

    PubMed Central

    McLeod, D

    1975-01-01

    The hypothesis that an occlusion of the central retinal artery is an essential prerequisite for haemorrhage formation after central retinal vein obstruction has been investigated by examining the fundus changes in patients with a cilio-retinal arterial circulation; the findings are at variance with the 'combined occlusion hypothesis'. Comparisons were made between the pathological features in two retinal capillary beds with independent sources of arterial supply--namely, the central retinal and cilio-retinal arteries--but with an obstructed venous drainage channel common to both--namely, the central retinal vein. The importance of intraluminal pressure changes (as distinct from perfusion changes) in the causation of haemorrhages and oedema after venous occlusion is stressed, and the role of arterial disease in the pathogenesis of venous occlusions is distinguished from its role in determining the sequelae of such occlusions. Images PMID:1203235

  10. Collateral Circulation in Chronic Total Occlusions - An Interventional Perspective

    PubMed Central

    Choo, Gim-Hooi

    2015-01-01

    Human coronary collaterals are inter-coronary communications that are believed to be present from birth. In the presence of chronic total occlusions, recruitment of flow via these collateral anastomoses to the arterial segment distal to occlusion provide an alternative source of blood flow to the myocardial segment at risk. This mitigates the ischemic injury. Clinical outcome of coronary occlusion ie. severity of myocardial infarction/ischemia, impairment of cardiac function and possibly survival depends not only on the acuity of the occlusion, extent of jeopardized myocardium, duration of ischemia but also to the adequacy of collateral circulation. Adequacy of collateral circulation can be assessed by various methods. These coronary collateral channels have been used successfully as a retrograde access route for percutaneous recanalization of chronic total occlusions. Factors that promote angiogenesis and further collateral remodeling ie. arteriogenesis have been identified. Promotion of collateral growth as a therapeutic target in patients with no suitable revascularization option is an exciting proposal.

  11. Influence of Occlusal Interference on the Mandibular Condylar Position

    PubMed Central

    Žaja, Matea; Kraljević, Sonja; Šimunković, Marijan; Kopić, Amir; Ćatić

    2016-01-01

    Aim The aim of this study was to determine the effect of occlusal interferences on the position of condyles. Materials and Methods The study included 10 participants. All recordings of the condylar position were done using ultrasound jaw tracking device with six degrees of freedom. Paraocclusal tray was fixed in the lower jaw, and the artificial occlusal interference was made on the lower left second premolar with a composite resin, thickness of 1 mm. Condylar shift at the position of the occlusion with the artificial occlusal interference was measured using a jaw tracking device. Condylar positions were determined based on the Cartesian coordinate system. All deviations were measured according to a reference position which was the position of maximum intercuspation. Linear values of deviations between the reference position and the position of the occlusion with the occlusal interference were determined from the values of the Cartesian coordinate system. Results Average superior condylar shift was 0.17 mm, SD 0.39. Average linear deviation between the position of maximum intercuspation and the position of the occlusion with the occlusal interference was 0.48 mm (SD 0.29, min 0.17 mm, max 1.19 mm). Conclusions Occlusal interference leads to immediate change of the condylar position within the temporomandibular joint. Average values of determined superior condylar position confirm occurrence of lever within dental arches. The obtained results must be interpreted within the limitations of this study (immediate measurement of the condylar position). Further research is needed for the analysis of progression of the condylar position with occlusal interferences. PMID:27789908

  12. Occlusal Therapy in the Management of Chronic Orofacial Pain

    PubMed Central

    Bush, Francis M.

    1984-01-01

    Review of the literature indicates that most routine orofacial dysfunctions are characterized by deep pain. Various disorders of the masticatory systems, particularly musculoskeletal conditions, are thought to be triggered by occlusal disharmonies. The pain component develops following a pattern of bruxism, muscle hyperactivity, fatigue and spasm. Treatment for most disorders has been to modify the occlusion, although the rational for doing so appears questionable. Critical issues in the field of occlusion related to orofacial pain are reviewed: occlusal disharmonies, coincidence of retruded-intercuspal contact positions, non-working side interferences, maximum intercuspation of teeth, occlusal adjustment, and occlusal appliances. The studies reviewed fail to support the clinical objective of obtaining equal contact at retruded and intercuspal positions and that the lateral pterygoid muscles stabilize the temporomandibular joint. The relationship between non-working side interferences and pain dysfunction is also not readily supported by controlled studies. Occlusal adjustment appears to be unsatisfactory as a modality for management of pain: not all patients improved following treatment, some relapse occurs even with the most stable contacts, and other treatments such as intra-articular injections of corticosteroids reduced symptoms more readily. Occlusal splints seem to reduce most clinical signs and symptoms on both a short-term and long-term basis. Placement of mandibular orthopedic repositioning appliances results in reduction of pain in some patients, but usually this treatment is followed by extensive rehabilitation. Six major areas are suggested for clinical studies that attempt to relate occlusion to management of orofacial pain. These include: establishment of an ideal jaw position, sequencing of symptoms in the pain history, relationship of pain to other symptoms, development of physiological methods to assess how occlusal modification affects pain

  13. Prosthetic occlusive device for an internal passageway

    NASA Technical Reports Server (NTRS)

    Tenney, J. B., Jr. (Inventor)

    1983-01-01

    An occlusive device is disclosed for surgical implant to occlude the lumen of an internal organ. The device includes a cuff having a backing collar and two isolated cuff chambers. The fluid pressure of one chamber is regulated by a pump/valve reservoir unit. The other chamber is unregulated in pressure but its fluid volume is adjusted by removing or adding fluid to a septum/reservoir by means of a hypodermic needle. Pressure changes are transmitted between the two cuff chambers via faying surfaces which are sufficiently large in contact area and thin as to transmit pressure generally without attenuation. By adjusting the fluid volume of the septum, the operating pressure of the device may be adjusted to accommodate tubular organs of different diameter sizes as well as to compensate for changes in the organ following implant without reoperation.

  14. Coil occlusion of a subclavian mycotic aneurysm.

    PubMed

    Kische, Stephan; Ince, Hüseyin; Peuster, Matthias

    2010-06-01

    We report the first successful application of nonferromagnetic embolization coils for endovascular exclusion of a mycotic right subclavian artery aneurysm. A 58-year-old woman presented with acute cervical pain and a pulsatile mass in the right supraclavicular fossa under antibiotic medication for subacute infectious endocarditis. Diagnostic work-up including duplex sonography, digital subtraction angiography, and magnetic resonance imaging demonstrated a saccular aneurysm of the extrathoracic right subclavian artery. As an alternative to open surgery or stent-graft repair, this pathology was electively treated by transcatheter coil embolization. No neurological deficit or ischemic symptoms were noted during 9 months clinical follow-up. Multislice computed tomography scan revealed complete occlusion of the mycotic aneurysm 6 months after the interventional procedure. Transcatheter closure with Inconel embolization coils is a cost-effective and safe therapeutic option in patients with mycotic aneurysm originating from the subclavian artery.

  15. Gastroesophageal reflux diagnosed by occlusal splint tintion.

    PubMed

    Cebrián-Carretero, José Luis; López-Arcas-Calleja, José María

    2006-01-01

    The gastroesophageal reflux (GER) disease is a very frequent digestive disorder, mainly characterised by the reflux of the gastric acidic content to the esophage in abnormal quantities. There are different situations that favour this situation but almost in all of them rely an incompetence of the esophagic sphincter. The clinical consequences are many, including oral manifestations. Among all of them the most frequent is the esophagitis followed by symptoms at the pharynx or larynx and finally, the oral cavity. At this level fundamentally we will find enamel and oral mucosa erosions. We report the case of a patient who was indirectly diagnosed of her esophague disease by the observation of the alterations in the occlusal splint induced by the gastric reflux. We review the literature concerning the above topic and its possible association with the miofascial syndrome.

  16. Robust visual tracking with contiguous occlusion constraint

    NASA Astrophysics Data System (ADS)

    Wang, Pengcheng; Qian, Weixian; Chen, Qian

    2016-02-01

    Visual tracking plays a fundamental role in video surveillance, robot vision and many other computer vision applications. In this paper, a robust visual tracking method that is motivated by the regularized ℓ1 tracker is proposed. We focus on investigating the case that the object target is occluded. Generally, occlusion can be treated as some kind of contiguous outlier with the target object as background. However, the penalty function of the ℓ1 tracker is not robust for relatively dense error distributed in the contiguous regions. Thus, we exploit a nonconvex penalty function and MRFs for outlier modeling, which is more probable to detect the contiguous occluded regions and recover the target appearance. For long-term tracking, a particle filter framework along with a dynamic model update mechanism is developed. Both qualitative and quantitative evaluations demonstrate a robust and precise performance.

  17. Comparison between dental and basal arch forms in normal occlusion and Class III malocclusions utilizing cone-beam computed tomography

    PubMed Central

    Suk, Kyung Eun; Park, Jae Hyun; Bayome, Mohamed; Nam, Young-Ok; Sameshima, Glenn T.

    2013-01-01

    Objective The purpose of this study was to investigate the relationship between the mandibular dental and basal arch forms in subjects with normal occlusion and compare them with those of Class III malocclusion using cone-beam computed tomography (CBCT). Methods CBCT images of 32 normal occlusion (19 males, 13 females; 24.3 years) and 33 Class III malocclusion subjects (20 males, 13 females, 22.2 years) were selected. Facial axis and root center points were identified from the left to right mandibular first molars. Distances between the facial axis and root center points for each tooth were calculated, and 4 linear and 2 ratio variables were measured and calculated for each arch form. The variables were compared between groups by independent t-test. Pearson correlation coefficient was applied to assess the relationships between dental and basal variables within each group. Results The mandibular dental and basal intercanine widths were significantly greater in the Class III group than in normal occlusion subjects (p < 0.05). The dental and basal intercanine widths as well as the dental and basal intermolar widths were strongly correlated in normal occlusion and moderately correlated in Class III malocclusion. Conclusions The dental arch form demon strated a strong positive correlation with the basal arch form in the normal occlusion group and moderate correlation in the Class III malocclusion group. These results might be helpful for clinicians to have a better understanding of the importance of basal arch form in the alveolar bone. PMID:23504406

  18. Coherent spatial and temporal occlusion generation

    NASA Astrophysics Data System (ADS)

    Klein Gunnewiek, R.; Berretty, R.-P. M.; Barenbrug, B.; Magalhães, J. P.

    2009-02-01

    A vastly growing number of productions from the entertainment industry are aiming at 3D movie theatres. These productions use a two-view format, primarily intended for eye-wear assisted viewing in a well defined environment. To get this 3D content into the home environment, where a large variety of 3D viewing conditions exists (e.g different display sizes, display types, viewing distance), we need a flexible 3D format that can adjust the depth effect. Such a format is the image plus depth format in which a video frame is enriched with depth information of all pixels in the video. This format can be extended with an additional layer for occluded video and associated depth, that contains what is behind objects in the video. To produce 3D content in this extended format, one has to deduce what is behind objects. There are various axes along which this occluded data can be obtained. This paper presents a method to automatically detect and fill the occluded areas exploiting the temporal axis. To get visually pleasing results, it is of utmost importance to make the inpainting globally consistent. To do so, we start by analyzing data along the temporal axis and compute a confidence for each pixel. Then pixels from the future and the past that are not visible in the current frame are weighted and accumulated based on computed confidences. These results are then fed to a generic multi-source framework that computes the occlusion layer based on the available confidences and occlusion data.

  19. Dynamic localized load balancing

    NASA Astrophysics Data System (ADS)

    Balandin, Sergey I.; Heiner, Andreas P.

    2003-08-01

    Traditionally dynamic load balancing is applied in resource-reserved connection-oriented networks with a large degree of managed control. Load balancing in connectionless networks is rather rudimentary and is either static or requires network-wide load information. This paper presents a fully automated, traffic driven dynamic load balancing mechanism that uses local load information. The proposed mechanism is easily deployed in a multi-vendor environment in which only a subset of routers supports the function. The Dynamic Localized Load Balancing (DLLB) mechanism distributes traffic based on two sets of weights. The first set is fixed and is inverse proportional to the path cost, typically the sum of reciprocal bandwidths along the path. The second weight reflects the utilization of the link to the first next hop along the path, and is therefore variable. The ratio of static weights defines the ideal load distribution, the ratio of variable weights the node-local load distribution estimate. By minimizing the difference between variable and fixed ratios the traffic distribution, with the available node-local knowledge, is optimal. The above mechanism significantly increases throughput and decreases delay from a network-wide perspective. Optionally the variable weight can include load information of nodes downstream to prevent congestion on those nodes. The latter function further improves network performance, and is easily implemented on top of the standard OSPF signaling. The mechanism does not require many node resources and can be implemented on existing router platforms.

  20. Effect of antenatal tracheal occlusion on lung development in the sheep model of congenital diaphragmatic hernia: a morphometric analysis of pulmonary structure and maturity.

    PubMed

    Lipsett, J; Cool, J C; Runciman, S I; Ford, W D; Kennedy, J D; Martin, A J

    1998-04-01

    The incidence of congenital diaphragmatic hernia (CDH) is 1:1,207-5,000, and the condition is associated with high mortality and morbidity, attributed principally to associated pulmonary hypoplasia. Repairing the diaphragmatic defect by antenatal surgery has high mortality, mainly due to premature labor. Antenatal tracheal occlusion, which is achievable by less invasive methods, stimulates lung growth (weight and DNA). However, its effectiveness in reversing structural and maturational abnormalities and its optimal timing requires further investigation. We hypothesized that (1) antenatal tracheal occlusion performed in the lamb model of congenital diaphragmatic hernia will stimulate lung growth and structural development and restore lung structure and maturity toward normal levels by term gestation; (2) effects will be detectable by morphometric measurements of the following parameters: lung volume, ratio of parenchyma to nonparenchyma, volume density of connective tissue within nonparenchyma, ratio of gas exchange tissue to airspace in parenchyma, gas exchange surface area, capillary loading, alveolar/airspace density and alveolar perimeter; (3) effects will be seen in all lobes of the lung; and (4) a greater effect will be observed when tracheal occlusion is performed early rather than late in gestation. Fourteen lambs underwent CDH creation at gestation day 72-74 followed by tracheal occlusion at day 101 (n = 7) or 129 (n = 7). They were delivered by Cesarean section at 143 days (term = 145-149). Lungs were obtained at autopsy, inflation fixed, divided into lobes, and sampled; morphometric analysis was performed. Comparisons were made with previously reported results from control lungs of normal lambs and lambs with untreated CDH. In comparison with untreated lungs, antenatal tracheal occlusion at both times resulted in increased volumes for total lung and lobes, increased volume density of parenchyma and of airspace within parenchyma, and increased gas exchange

  1. Biomechanics of occlusion--implications for oral rehabilitation.

    PubMed

    Peck, C C

    2016-03-01

    The dental occlusion is an important aspect of clinical dentistry; there are diverse functional demands ranging from highly precise tooth contacts to large crushing forces. Further, there are dogmatic, passionate and often diverging views on the relationship between the dental occlusion and various diseases and disorders including temporomandibular disorders, non-carious cervical lesions and tooth movement. This study provides an overview of the biomechanics of the masticatory system in the context of the dental occlusion's role in function. It explores the adaptation and precision of dental occlusion, its role in bite force, jaw movement, masticatory performance and its influence on the oro-facial musculoskeletal system. Biomechanics helps us better understand the structure and function of biological systems and consequently an understanding of the forces on, and displacements of, the dental occlusion. Biomechanics provides insight into the relationships between the dentition, jaws, temporomandibular joints, and muscles. Direct measurements of tooth contacts and forces are difficult, and biomechanical models have been developed to better understand the relationship between the occlusion and function. Importantly, biomechanical research will provide knowledge to help correct clinical misperceptions and inform better patient care. The masticatory system demonstrates a remarkable ability to adapt to a changing biomechanical environment and changes to the dental occlusion or other components of the musculoskeletal system tend to be well tolerated.

  2. Effects of resistance training combined with vascular occlusion or hypoxia on neuromuscular function in athletes.

    PubMed

    Manimmanakorn, Apiwan; Manimmanakorn, Nuttaset; Taylor, Robert; Draper, Nick; Billaut, Francois; Shearman, Jeremy P; Hamlin, Michael J

    2013-07-01

    The aim was to investigate the effects of low-load resistant training combined with vascular occlusion or normobaric hypoxic exposure, on neuromuscular function. In a randomised controlled trial, well-trained athletes took part in a 5-week training of knee flexor/extensor muscles in which low-load resistant exercise (20% of one repetition maximum, 1-RM) was combined with either (1) an occlusion pressure of approximately 230 mmHg (KT, n = 10), (2) hypoxic air to generate an arterial blood oxygen saturation of ~80% (HT, n = 10), or (3) with no additional stimulus (CT, n = 10). Before and after training, participants completed the following tests: 3-s maximal voluntary contraction (MVC₃), 30-s MVC, and an endurance test (maximal number of repetitions at 20% 1-RM, Reps₂₀). Electromyographic activity (root mean square, RMS) was measured during tests and the cross-sectional area (CSA) of the quadriceps and hamstrings was measured pre- and post-training. Relative to CT, KT, and HT showed likely increases in MVC₃ (11.0 ± 11.9 and 15.0 ± 13.1%, mean ± 90% confidence interval), MVC₃₀ (10.2 ± 9.0 and 18.3 ± 17.4%), and Reps₂₀ (28.9 ± 23.7 and 23.3 ± 24.0%). Compared to the CT group, CSA increased in the KT (7.6 ± 5.8) and HT groups (5.3 ± 3.0). KT had a large effect on RMS during MVC₃, compared to CT (effect size 0.8) and HT (effect size 0.8). We suspect hypoxic conditions created within the muscles during vascular occlusion and hypoxic training may play a key role in these performance enhancements.

  3. Three-dimensional finite element modeling of the human external ear: simulation study of the bone conduction occlusion effect.

    PubMed

    Brummund, Martin K; Sgard, Franck; Petit, Yvan; Laville, Frédéric

    2014-03-01

    A linear three-dimensional (3D) elasto-acoustic finite element model was used to simulate the occlusion effect following mechanical vibration at the mastoid process. The ear canal and the surrounding soft and bony tissues were reconstructed using images of a female cadaver head (Visible Human Project(®)). The geometrical model was coupled to a 3D earplug model and imported into comsol Multiphysics (COMSOL(®), Sweden). The software was used to solve for the sound pressure at the eardrum. Finite element modeling of the human external ear and of the occlusion effect has several qualities that can complement existing measuring and modeling techniques. First, geometrically complex structures such as the external ear can be reconstructed. Second, various material behavioral laws and complex loading can be accounted for. Last, 3D analyses of external ear substructures are possible allowing for the computation of a broad range of acoustic indicators. The model simulates consistent occlusion effects (e.g., insertion depth variability). Comparison with an experimental dataset, kindly provided by Stenfelt and Reinfeldt [Int. J. Audiol. 46, 595-608 (2007)], further demonstrates the model's accuracy. Power balances were used to analyze occlusion effect differences obtained for a silicone earplug and to examine the increase in sound energy when the ear canal is occluded (e.g., high-pass filter removal).

  4. Coil Occlusion of the Patent Ductus Arteriosus: Lessons Learned

    SciTech Connect

    Sanatani, Shubhayan; Potts, James E.; Ryan, Angela; Sandor, George G.S.; Human, Derek G.; Culham, J.A. Gordon

    2000-03-15

    Purpose: To review the clinical outcomes of catheter-directed coil occlusion (coil occlusion) of persistently patent ductus arteriosus (PDA) at a pediatric tertiary care hospital.Methods: A retrospective review of all patients referred to the Cardiac Catheterization Laboratory for coil occlusion at our institution was performed. Twenty-one consecutive patients (12 female) underwent coil occlusion and follow-up between May 1995 and December 1997. We undertook PDA occlusion if: (a) the PDA narrowed to less than 4 mm on echocardiogram and (b) the minimum body weight was approximately 10 kg. Standard right and retrograde left heart catheterization was performed, followed by coil occlusion. Color-flow mapping (CFM) was used intra-procedurally to confirm occlusion of the PDA with a follow-up study several weeks later.Results: The median age and weight of the patients were 33 months and 13.2 kg, respectively. Fourteen patients received one coil, with six requiring a second coil and one requiring multiple coils. Initial follow-up was at a median of 2.4 months. At latest follow-up, 2 patients still have persistent flow at the ductal level. The coils were deployed without complication or embolization.Conclusions: A review of our first 21 cases demonstrated three important lessons: (1) the maximum diameter of the PDA suitable for coil occlusion is approximately 3 mm; (2) CFM must show complete obliteration of flow in the catheterization lab in order to ensure occlusion of the PDA at follow-up; and (3) the Jackson detachable system allows for precise placement of the coil, often within another coil.

  5. Coil occlusion of the paient ductus arteriosus: lessons learned

    SciTech Connect

    Sanatani, Shubhayan; Potts, James E.; Ryan, Angela; Sandor, George G. S.; Human, Derek G.; Culham, J. A. Gordon

    2000-03-15

    Purpose: To review the clinical outcomes of catheter-directed coil occlusion (coil occlusion) of persistently patent ductus arteriosus (PDA) at a pediatric tertiary care hospital.Methods: A retrospective review of all patients referred to the Cardiac Catheterization Laboratory for coil occlusion at our institution was performed. Twenty-one consecutive patients (12 female) underwent coil occlusion and follow-up between May 1995 and December 1997. We undertook PDA occlusion if: (a) the PDA narrowed to less than 4 mm on echocardiogram and (b) the minimum body weight was approximately 10 kg. Standard right and retrograde left heart catheterization was performed, followed by coil occlusion. Color-flow mapping (CFM) was used intra-procedurally to confirm occlusion of the PDA with a follow-up study several weeks later.Results: The median age and weight of the patients were 33 months and 13.2 kg, respectively. Fourteen patients received one coil, with six requiring a second coil and one requiring multiple coils. Initial follow-up was at a median of 2.4 months. At latest follow-up, 2 patients still have persistent How at the ductal level. The coils were deployed without complication or embolization.Conclusions: A review of our first 21 cases demonstrated three important lessons: (1) the maximum diameter of the PDA suitable for coil occlusion is approximately 3 mm; (2) CFM must show complete obliteration of flow in the catheterization lab in order to ensure occlusion of the PDA at follow-up; and (3) the Jackson detachable system allows for precise placement of the coil, often within another coil.

  6. Central retinal artery occlusion (reversible in sickle trait with glaucoma.

    PubMed Central

    Radius, R L; Finkelstein, D

    1976-01-01

    We report a case of central retinal artery occlusion in an 18-year-old black woman with sickle-trait haemoglobinopathy and acute glaucoma after hyphaema. The central retinal artery occlusion occurred immediately after treatment of the glaucoma with osmotic agents, raising the possibility that they played a precipitating role. We suggest that osmotic agents be used with extreme caution in sickle patients with glaucoma. The occlusion was treated by anterior chamber paracentesis with eventual return of good vision. The reversibility of retinal and optic nerve function after total ischaemia is discussed. PMID:952815

  7. Central Retinal Vein Occlusion Associated With Severe Vitamin D Deficiency.

    PubMed

    Talcott, Katherine E; Eliott, Dean

    2016-04-01

    Central retinal vein occlusion (CRVO) is thought to occur due to thrombotic occlusion of the central retinal vein at or just posterior to the lamina cribrosa. Studies have shown that the incidence of CRVO may be higher in winter to early spring, suggesting that low vitamin D levels may play a role; however, no studies have measured vitamin D levels in patients with CRVO. In addition, there is mounting evidence that patients with vitamin D deficiency may be predisposed to thrombotic events. The authors report a case of central retinal vein occlusion associated with marked vitamin D deficiency.

  8. Radiographic evaluation of occlusal caries: effect of training and experience.

    PubMed

    Lazarchik, D A; Firestone, A R; Heaven, T J; Filler, S J; Lussi, A

    1995-01-01

    The purpose of this study was to investigate what effect differing levels of didactic education and clinical experience have on the ability to diagnose occlusal caries from radiographs. Freshman and senior dental students and dental school faculty were asked to evaluate bitewing radiographs for the presence of occlusal caries and for a recommendation for restorative treatment. The agreement between histologic and radiographic diagnosis was assessed by calculating sensitivity, specificity, accuracy, and interexaminer agreement. It was concluded that dental students and faculty did differ in their abilities to evaluate radiographs for occlusal caries, and that education and clinical experience especially affected interexaminer agreement.

  9. 14 CFR 29.511 - Ground load: unsymmetrical loads on multiple-wheel units.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Requirements Ground Loads § 29.511 Ground load: unsymmetrical loads on multiple-wheel units. (a) In dual-wheel gear units, 60 percent of the total ground reaction for the gear unit must be applied to one wheel and... specified load for the gear unit must be applied to either wheel except that the vertical ground...

  10. 14 CFR 29.511 - Ground load: unsymmetrical loads on multiple-wheel units.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Requirements Ground Loads § 29.511 Ground load: unsymmetrical loads on multiple-wheel units. (a) In dual-wheel gear units, 60 percent of the total ground reaction for the gear unit must be applied to one wheel and... specified load for the gear unit must be applied to either wheel except that the vertical ground...

  11. 14 CFR 29.511 - Ground load: unsymmetrical loads on multiple-wheel units.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Requirements Ground Loads § 29.511 Ground load: unsymmetrical loads on multiple-wheel units. (a) In dual-wheel gear units, 60 percent of the total ground reaction for the gear unit must be applied to one wheel and... specified load for the gear unit must be applied to either wheel except that the vertical ground...

  12. Thickness and marking quality of different occlusal contact registration strips

    PubMed Central

    TOLEDO, Maria Fernanda de Souza Mauá Serapião; JÓIAS, Renata Pilli; MARQUES-IASI, Yves Santini; NEVES, Ana Christina Claro; RODE, Sigmar de Mello

    2014-01-01

    Objectives Evaluate the thickness and the marking quality of different occlusal contact registration strips (OCRS) and a possible correlation between them. Material and Methods The following OCRS were selected: Accufilm II, BK20, BK21, BK22, BK23, BK28, and BK31. The thickness was measured in three points of the OCRS with an electronic measuring device (TESA), and the mean was calculated. To produce the marks on the strips, composite resin specimens were adapted to a universal testing machine (Versat 2000) with 40 kgf load cell at a speed of 1.0 mm/min. The mark images were photographed with a stereoscopic microscope (Stemi SV11) and processed and analyzed by the 550-Leica Qwin® analyzer. Results Values (μm) found in the 1st and 2nd thickness measurements were: Accufilm II - 16.4 and 14.2; BK20 - 10.0 and 8.1; BK21 - 9.5 and 8.0; BK22 - 9.7 and 8.7; BK23 - 9.8 and 7.9; BK28 - 12.8 and 10.0; and BK31 - 8.4 and 8.0, respectively. The mean (mm2) values found in the mark areas were: Accufilm II - 0.078; BK20 - 0.035; BK21 - 0.045; BK22 - 0.012; BK23 - 0.022; BK28 - 0.024; and BK31 - 0.024. The results were submitted to the Kruskal-Wallis (p<0.05) and Pearson’s correlation tests. Conclusions Only in the 2nd measurement, the OCRS thickness observed was similar to the value indicated by the manufacturers; the Accufilm II and the BK28 strips showed the better marks; and no correlation was found between the thickness and the marking area. PMID:25591020

  13. Two-body wear of occlusal splint materials.

    PubMed

    Kurt, H; Erdelt, K-J; Cilingir, A; Mumcu, E; Sülün, T; Tuncer, N; Gernet, W; Beuer, F

    2012-08-01

    This study investigates the wear resistance of four different types of occlusal splint materials based on two-body wear simulations under wet and dry conditions. Twenty specimens of each splint material (Dentalon Plus, Orthoplast, Biocryl C, and Eclipse), each with a diameter of 16 mm and a thickness of 3 mm, were tested, half under wet and half under dry conditions. Each wear test was performed using a device called chewing simulator CS-4 (n=10; test load: 50 N; number of cycles: 10000, 20000, and 30000; continuous rinsing with 30°C water for wet conditions); the antagonists were simulated using steel balls. Wear was determined using a 3D laser scanner and a surface analysis program. To detect significant statistical differences, wear data after 10000; 20000; and 30000 cycles were compared using the Kruskal-Wallis test and the Mann-Whitney U-test. The level of significance was set at 5%. Significant differences were found between the groups of different materials tested under wet conditions (P<0.05), whereas no differences between them were found under dry conditions (P>0.05). No significant difference was found between the wet and dry conditions for all materials and cycles (P>0.05). For groups of different materials tested under wet conditions, the degree of volume loss generated in the Chewing Simulator CS-4 was found to differ significantly for different numbers of cycles. The presence of water had no effect on the volume loss in the different material groups that were tested.

  14. Serial dependence promotes object stability during occlusion

    PubMed Central

    Liberman, Alina; Zhang, Kathy; Whitney, David

    2016-01-01

    Object identities somehow appear stable and continuous over time despite eye movements, disruptions in visibility, and constantly changing visual input. Recent results have demonstrated that the perception of orientation, numerosity, and facial identity is systematically biased (i.e., pulled) toward visual input from the recent past. The spatial region over which current orientations or face identities are pulled by previous orientations or identities, respectively, is known as the continuity field, which is temporally tuned over the past several seconds (Fischer & Whitney, 2014). This perceptual pull could contribute to the visual stability of objects over short time periods, but does it also address how perceptual stability occurs during visual discontinuities? Here, we tested whether the continuity field helps maintain perceived object identity during occlusion. Specifically, we found that the perception of an oriented Gabor that emerged from behind an occluder was significantly pulled toward the random (and unrelated) orientation of the Gabor that was seen entering the occluder. Importantly, this serial dependence was stronger for predictable, continuously moving trajectories, compared to unpredictable ones or static displacements. This result suggests that our visual system takes advantage of expectations about a stable world, helping to maintain perceived object continuity despite interrupted visibility. PMID:28006066

  15. Clinical Trials in Branch Retinal Vein Occlusion

    PubMed Central

    Panakanti, Tandava Krishnan; Chhablani, Jay

    2016-01-01

    Branch retinal vein occlusion (BRVO) is the second most common retinal vascular disorder. The management of macular edema has changed considerably over time. The laser is considered the gold standard treatment for over two decades. However, visual recovery with laser is usually slow and incomplete. The advent of intravitreal agents, specifically anti-vascular endothelial growth factors (VEGF) have heralded a new era which promises rapid recovery of vision and quality of vision. Randomized clinical trials have reported optimal results with anti-VEGF agents (ranibizumab, bevacizumab, and aflibercept) compared to laser therapy or steroids. However, nearly 50% of the patients require repeat intravitreal anti-VEGF therapy up to 4 years after initiating therapy to sustain the visual gains. The adverse events (systemic and ocular) of these agents are minimal. Monotherapy with anti-VEGF agents have been found to provide better results than any combination with laser. This review article summarizes evidence from randomized controlled trials evaluating treatment options for the treatment of macular edema secondary to BRVO with a special focus on anti-VEGF therapy. PMID:26957837

  16. Local histograms and image occlusion models

    PubMed Central

    Massar, Melody L.; Bhagavatula, Ramamurthy; Fickus, Matthew; Kovačević, Jelena

    2012-01-01

    The local histogram transform of an image is a data cube that consists of the histograms of the pixel values that lie within a fixed neighborhood of any given pixel location. Such transforms are useful in image processing applications such as classification and segmentation, especially when dealing with textures that can be distinguished by the distributions of their pixel intensities and colors. We, in particular, use them to identify and delineate biological tissues found in histology images obtained via digital microscopy. In this paper, we introduce a mathematical formalism that rigorously justifies the use of local histograms for such purposes. We begin by discussing how local histograms can be computed as systems of convolutions. We then introduce probabilistic image models that can emulate textures one routinely encounters in histology images. These models are rooted in the concept of image occlusion. A simple model may, for example, generate textures by randomly speckling opaque blobs of one color on top of blobs of another. Under certain conditions, we show that, on average, the local histograms of such model-generated-textures are convex combinations of more basic distributions. We further provide several methods for creating models that meet these conditions; the textures generated by some of these models resemble those found in histology images. Taken together, these results suggest that histology textures can be analyzed by decomposing their local histograms into more basic components. We conclude with a proof-of-concept segmentation-and-classification algorithm based on these ideas, supported by numerical experimentation. PMID:23543920

  17. [Veno-occlusive disease of the liver].

    PubMed

    Rybicka, Malwina; Krysiak, Robert; Okopień, Bogusław

    2009-01-01

    Veno-occlusive disease (VOD) is seen most often in the group of bone marrow transplant recipients. The essence of this disease is the obstruction of the hepatic sinusoidal and centrolobular venous outflow, because of the injury to the endothelium of the liver vessels. It results in congestion of the liver and hepatomegaly. The typical clinical symptoms of VOD are: jaundice, portal hypertension with peripheral oedemas and the weight gain. Depending on the extent of the injury of the hepatic vessels, VOD is divided into three grades: mild, moderate and severe. The clinical markers that inform about the severity of the disease are: the rate of the serum bilirubin growth and the rate of the weight gain growth within the first 2 weeks since the beginning of the disease. Severe VOD is the third of the most often cause of death among people who underwent bone marrow transplantation. The mortality rate is diverse and depends on severity of the disease. The effectiveness of the VOD therapy is limited, so it is worth putting greater pressure on the prophylaxis of VOD or on finding more effective modes of treatment.

  18. Transient stenotic-like occlusions as a possible mechanism for renovascular hypertension due to aneurysm.

    PubMed

    Heflin, Linden A; Street, Carrie B; Papavassiliou, Dimitrios V; Kem, David C; Wu, Dee H; O'Rear, Edgar A

    2009-01-01

    The pathophysiologic basis of hypertension secondary to a renal artery aneurysm has not been established. Changes in renal artery geometry and resultant hemodynamic alterations activate the renin-angiotensin-aldosterone system and lead to hypertension. Hemodynamic pressure losses created by blood flowing through an abnormally structured renal artery with an aneurysm predictably would provoke a similar circumstance. The present study provides a hemodynamic rationale for this hypothesis. Using computational fluid dynamics, we have modeled renal flow for selected aneurysmal geometries. These studies reveal that pressure loss across the renal artery does not change ( approximately 0.9 mm Hg) significantly when a nondeformable aneurysm is interposed on the system. The calculations, however, demonstrate that the pressure on the aneurysm walls supports the presence of forces deforming and thereby obstructing the renal artery. A deformed wall was assumed and various degrees of occlusion were modeled. A partial occlusion of 60% resulted in a renal artery pressure loss of approximately 10 mm Hg. These simulations, when applied to aneurysms at various locations on the renal artery and with various degrees of occlusion, consistently resulted in pathologically relevant pressure losses. These findings lead to a new hypothesis of how aneurysms are associated with renovascular hypertension.

  19. SURGICAL EMBOLECTOMY FOR FOVEA-THREATENING ACUTE RETINAL ARTERY OCCLUSION

    PubMed Central

    Almeida, David R.P.; Mammo, Zaid; Chin, Eric K.

    2016-01-01

    Purpose: To describe a technique of surgical intraocular embolectomy in patients with acute fovea-threatening branch retinal artery occlusion. Methods: Pars plana vitrectomy with embolectomy involving embolus isolation, dissection, and removal in patients with an acute fovea-threatening arterial occlusion without a patent cilioretinal artery. Results: The surgical technique involves a core vitrectomy. The blocked artery is incised using a microvitreoretinal blade, and microsurgical forceps are used to retrieve the embolus. No significant complications were noted. The study technique offers an excellent safety profile and minimizes the risk of vitreous hemorrhage by carefully dissecting the vascular adventitial sheath and isolating the embolus. Conclusion: Surgical embolectomy is a viable technique for patients with acute fovea-threatening arterial occlusions without patent cilioretinal artery. Careful dissection and retrieval of the embolus minimizes the risk of vitreous hemorrhage, which is an important improvement in previous techniques for management of acute retinal arterial occlusions. PMID:26674278

  20. Different Occlusal Schemes in a Persistent Protruding Complete Denture Wearer

    PubMed Central

    Iegami, Carolina Mayumi; Lopes, Danilo de Melo; Nakamae, Atlas Edson Moleros; Uehara, Priscila Nakasone; Tamaki, Regina

    2016-01-01

    Different types of artificial teeth and occlusal designs can be used in complete dentures. Bilateral balanced occlusion, lingualized occlusion, canine guidance, and monoplane are the main occlusal designs; however there is no agreement on which tooth arrangement is ideal for achieving success in complete dentures. This report presents an alternative for persistent involuntary protruding complete denture wearers through the use of artificial teeth with higher cusps. Due to an old and worn pair of complete dentures, the patient had the habit of protruding. New dentures were made with Biotone artificial teeth and in the trial session, the patient would still protrude. A new set was made with Premium artificial teeth, which present higher cusps. With these dentures, the involuntary protrusion did not occur. From the delivery to the follow-up sessions, the patient stopped protruding. PMID:27069698

  1. Aortoiliac occlusive disease presenting as sudden onset paraplegia.

    PubMed

    Lai, Chien-Hung; Wang, Cheng-Hsien; Wu, Shih-Yun; Shih, Hong-Mo

    2014-07-01

    Thromboembolism and atherosclerotic stenosis both can cause arterial occlusion. Aortoiliac occlusive disease involving bifurcation of the aortoiliac artery induces symptoms of ischemia such as claudication and pain of buttocks and thighs, decreased bilateral femoral pulses, and impotence. Here, we describe a 58-year-old woman with a past history of atrial fibrillation and lacuna stroke with minimal right side weakness. She presented to our emergency department with sudden onset bilateral pain in the legs and paraplegia. A comprehensive examination revealed paresthesia and decreasing bilateral distal pulses. Computed tomographic imaging showed filling defects over the low abdominal aorta just above the bifurcation of the common iliac artery and bilateral femoral arteries. Acute aortic embolic occlusion was suspected. Her symptoms were resolved after emergent thrombectomy for acute limb ischemia. Physicians need to be aware of aortoiliac embolic occlusive disease which may present as acute paraplegia.

  2. Diagnosis and management of occlusal wear: a case report.

    PubMed

    Thirumurthy, V R; Bindhoo, Y A; Jacob, Sunil Joseph; Kurien, Anjana; Limson, K S; Vidhiyasagar, P

    2013-09-01

    The rationale for doing full mouth rehabilitation are, when occlusal forces become traumatic hampering the health of periodontal tissues, extensive occlusal diseases, trauma, temporomandibular joint disease and congenital disorders with malformed dentition. Literature exposes that full mouth fixed rehabilitation is one of the taxing procedures in the field of Prosthodontics. A critical aspect for successful occlusal rehabilitation is to determine the aetiology, correct sequence of treatment and most importantly the occlusal vertical dimension and centric relation in which to plan the treatment. A systematic approach in managing these patients can lead to a predictable and favourable prognosis. This article presents the stages of prosthodontic rehabilitation, from diagnosis to final treatment and follow-up, of a bruxer patient with severely worn dentition.

  3. Pulmonary veno-occlusive disease and pulmonary capillary hemangiomatosis.

    PubMed

    Ortiz-Bautista, Carlos; Hernández-González, Ignacio; Escribano-Subías, Pilar

    2017-03-22

    Pulmonary veno-occlusive disease is a rare cause of pulmonary hypertension which is part, together with pulmonary capillary hemangiomatosis, of the special designation (subgroup 1') within pulmonary hypertension group 1 in the latest classification of the pulmonary hypertension World Symposium. Recent discovery that gene mutations in eukaryotic translation initiation factor 2 alpha kinase 4 (EIF2AK4) are responsible for inherited forms of pulmonary veno-occlusive disease has changed the role of genetic testing, acquiring relevant importance in the diagnosis of these patients. Despite the advances in genetic, cellular and molecular basis knowledge in the last decade, pulmonary veno-occlusive disease remains as a rare aetiology of pulmonary hypertension without any effective medical treatment approved and poor outcomes. This document aims to review the advances occurred in the understanding of pulmonary veno-occlusive disease in the last years.

  4. Bilateral atherosclerotic internal carotid artery occlusion and recurrent ischaemic stroke.

    PubMed

    Amin, Osama S M

    2015-06-08

    Bilateral internal carotid artery occlusion (BICAO) is a rare disease that carries a gloomy prognosis. We report a case of a 52-year-old man who developed ischaemic infarction at the region of the right middle cerebral artery; he was found to have atherosclerotic occlusion of both internal carotid arteries on Doppler-duplex examination. He received medical treatment only. After 1 year, he developed a new infarction at the region of the left middle cerebral artery. Conventional angiography revealed bilateral occlusion of internal carotid arteries at their origin, approximately 50% stenosis of the common carotid bulbs and mild stenosis of the origin of external carotid arteries. The patient did not undergo any form of surgical revascularisation procedures and died of severe aspiration pneumonia approximately 2 months after the second stroke. BICAO portends a poor outcome and carries a risk of recurrent ischaemic events. The best management strategy for this vascular occlusion remains unclear.

  5. A Moyamoya Patient with Bilateral Consecutive Branch Retinal Vein Occlusion

    PubMed Central

    Güçlü, Hande; Gurlu, Vuslat Pelitli; Ozal, Sadık Altan; Esgin, Haluk

    2016-01-01

    ABSTRACT We describe a moyamoya (MMD) patient with bilateral consecutive branch retinal vein occlusion (BRVO). The patient had a medical history of severe headache, cranial haemorrhage, bilateral supraclinoid carotid artery occlusion, and “puff of smoke” collaterals on cerebral angiography and an encephalomyosynangiosis operation. On ophthalmic examination, he had superior temporal branch vein occlusion with intraretinal haemorrhage and visual acuity of 20/25 in the right eye. Twelve years later, he presented with superior temporal branch vein occlusion in the left eye and visual acuity of 20/60. The patient was initially treated with a dexamethasone intravitreal implant, and later intravitreal ranibizumab injections. We describe the first reported case of bilateral consecutive BRVO and management in MMD. PMID:27928391

  6. Clinical and angiographic comparison of asymptomatic occlusive cerebrovascular disease.

    PubMed

    Gorelick, P B; Caplan, L R; Langenberg, P; Hier, D B; Pessin, M; Patel, D; Taber, J

    1988-06-01

    We compared clinical and arteriographic features in 106 patients with symptomatic unilateral carotid territory occlusive disease to determine the frequency and distribution of occlusive arterial lesions in asymptomatic vessels. Among black patients who were predominantly from Chicago, young, and female, there were fewer transient ischemic attacks and myocardial infarcts, less claudication, and more asymptomatic lesions of the supraclinoid internal carotid artery, anterior cerebral artery stem, and the middle cerebral artery stem. Among white patients predominantly from New England, elderly, and male, there was more frequent and severe occlusive asymptomatic disease at extracranial carotid and vertebral artery sites. Knowledge of the distribution of asymptomatic lesions will help guide evaluation and treatment strategies for patients with occlusive cerebrovascular disease.

  7. Acute Popliteal Artery Occlusion after Revision Total Knee Arthroplasty.

    PubMed

    Tsujimoto, Ryu; Matsumoto, Tomoyuki; Takayama, Koji; Kawakami, Yohei; Kamimura, Masato; Matsushita, Takehiko; Kuroda, Ryosuke; Kurosaka, Masahiro

    2015-01-01

    Acute arterial occlusions are a rare complication of total knee arthroplasty (TKA). However, in revision TKA, the risk of such complications is higher and these complications can lead to amputation if not adequately treated. We describe a case of acute popliteal artery occlusion 4 hours after second revision TKA in a patient with a history of several surgical procedures because of periprosthetic infection at a previous hospital. Revascularization was achieved via bypass grafting and amputation was narrowly avoided despite time lag after symptom onset to revascularization. In this case, it was possible that the arterial disease that accompanied the vascular endothelium injury such as pseudoaneurysm had existed since the previous surgery at another hospital and was destroyed by the surgical procedure, which led to the formation of thrombosis and arterial occlusion. Preoperative evaluation of the arterial condition should be considered to avoid acute arterial occlusive disease, especially in patients who had several previous surgical procedures.

  8. Endovascular treatment of iliac occlusive disease: review and update.

    PubMed

    Mousa, Albeir Y; Beauford, Robert B; Flores, Lucio; Faries, Peter L; Patel, Prem; Fogler, Richard

    2007-01-01

    Use of endovascular interventions for arterial occlusive lesions continues to increase. With the evolution of the technology supporting these therapeutic measures, the results of these interventions continue to improve. In general, a comparison of techniques for revascularization of iliac occlusive diseases shows similar initial technical success rates for open versus percutaneous transluminal angioplasty. Angioplasty is often associated with lower periprocedural morbidity and mortality rates. Conversely, surgery frequently provides greater long-term patency, although late failure of percutaneous therapies may occur but still can be treated successfully with reintervention. The perpetual buildup of experience with angioplasty and stenting will eventually characterize its role in the management of occlusive disease. This review outlines the current consensus and applicability of endovascular management of iliac occlusive diseases.

  9. Thermolabile MTHFR genotype and retinal vascular occlusive disease

    PubMed Central

    Cahill, M; Karabatzaki, M; Donoghue, C; Meleady, R; Mynett-Johnson, L; Mooney, D; Graham, I; Whitehead, A; Shields, D

    2001-01-01

    BACKGROUND—Raised levels of total plasma homocysteine (tHcy) are associated with an increased risk of retinal vascular occlusive disease. A thermolabile form of a pivotal enzyme in homocysteine metabolism, methylenetetrahydrofolate reductase (MTHFR), has been associated with vascular occlusive disease and raised tHcy levels. The relation between thermolabile MTHFR genotype, tHcy, and retinal vascular occlusive disease has not been determined.
METHODS—A retrospective case-control study involving hospital based controls and cases with retinal vascular occlusions in whom tHcy levels had been determined was undertaken. Genotyping for the MTHFR 677 C-T mutation that specifies the thermolabile form of the enzyme was performed by established methods in all subjects. The relation between homozygosity for thermolabile MTHFR genotype (TT), raised tHcy levels, and risk of retinal vascular occlusive disease was examined.
RESULTS—87 cases of retinal vascular occlusive disease (mean age 68.7 years) comprising 26 cases of retinal artery occlusion and 61 of retinal vein occlusion were compared with 87 controls (mean age 70.2 years). The TT genotype did not confer a significantly increased risk of retinal vascular occlusive disease. The mean tHcy level was significantly higher in the cases than in the controls (p<0.0001). Overall, and in both the cases and controls, the frequency of the TT genotype was higher in those with normal tHcy levels than in those with increased levels of tHcy. However, the TT genotype did not significantly alter the risk of increased tHcy levels in these patients.
CONCLUSIONS—The TT genotype is not associated with an increased risk of retinal vascular occlusive disease or increased tHcy levels in this group of elderly patients. In older patients, nutritional rather than genetic factors may be more important in increasing tHcy levels, a known risk factor for retinal vascular occlusive disease.

 PMID:11133719

  10. Branch retinal vein occlusion associated with quetiapine fumarate

    PubMed Central

    2011-01-01

    Background To report a case of branch retinal vein occlusion in a young adult with bipolar mood disorder treated with quetiapine fumarate. Case Presentation A 29 years old gentleman who was taking quetiapine fumarate for 3 years for bipolar mood disorder, presented with sudden vision loss. He was found to have a superior temporal branch retinal vein occlusion associated with hypercholesterolemia. Conclusion Atypical antipsychotic drugs have metabolic side effects which require regular monitoring and prompt treatment. PMID:21867521

  11. Pathophysiological aspects of sickle cell vaso-occlusion

    SciTech Connect

    Nagel, R.L.

    1987-01-01

    This book contains over 30 selections. Some of the titles are: An Animal Model for Sickle Cell Vaso-Occlusion: A Study Using NMR and Technetium Imaging; Sickle-Cell Vaso-Occlusion in an Animal Model: Intravital Microscopy and Radionuclide Imaging of Selective Sequestration of Dense Cells; Magnetic Resonance Imaging, Percentage of Dense Cells, and Serum Prostanoids as Tools for Objective Assessment of Pain Crisis: A Preliminary Report; and Painful Crisis and Dense Echinocytes: Effects of Hydration and Vasodilators.

  12. Trauma from occlusion — An orthodontist’s perspective

    PubMed Central

    Saravanan, R.; Babu, Prajeeth J.; Rajakumar, P.

    2010-01-01

    Orthodontic therapy has a big role in the treatment and prevention of malpositions. The signs and symptoms experienced by patients with occlusal trauma are mobility of teeth, temperomandibular joint pain, pain on mastication and periodontal disease. Early diagnosis, proper treatment plan and correction of malocclusion can lead to a successful outcome. Lack of awareness of orthodontic treatment in patients with occlusal trauma can even lead to loss of tooth structure. PMID:21691555

  13. Acrylic strengthened casts for removable partial denture for occlusion equilibration.

    PubMed

    Oh, Won-Suk; Saglik, Berna

    2011-09-01

    A removable partial denture (RPD) remount cast must resist wear or breakage, present a rigid surface, and ensure a solid support for an accurate equilibration of the occlusion for a RPD. This article describes a procedure of processing a thin layer of tooth colored acrylic resin over the dental plaster to present wear- and fracture-resistant incisal/occlusal surfaces without involving a third material.

  14. Isolated supraclinoid occlusive disease of the internal carotid artery.

    PubMed

    Lagrèze, H L; Hartmann, A; Ries, F; Wappenschmidt, J; Hanisch, E

    1987-01-01

    Isolated supraclinoid occlusive disease of the internal carotid artery is a rare cause of cerebral ischemia. The authors of the only review of this subject concluded that it is caused predominantly by factors other than atherosclerosis. We examined 6 patients with isolated supraclinoid occlusive lesions. Five of them had one or more risk factors for atherosclerosis. Thus, the isolated stenosis of that part of the internal carotid artery does not seem to represent a particular pathologic entity.

  15. Evidence Relating Subjective Contours and Interpretations Involving Occlusion.

    DTIC Science & Technology

    1981-06-01

    This article describes a patient with visual agnosia who is both unable to make the usual occlusion interpretations and is unable to see subjective... article describes a patient with visual agnosia who is both unable to make the usual occlusion interpretions and is unable to see subjective contours...Subjective contours This article examines a prediction that follows from the following two postulates of the above theory: (i) that subjective

  16. An Investigation of the Posterior Component of Occlusal Force

    DTIC Science & Technology

    1994-05-01

    Orthodontists have for decades sought to understand the factors involved in maintaining teeth in corrcted positions following orthodontic treatment Weinstein...procedures such as the circumferential supracrestal fiberotomy in enhancing stability. The role of occlusion contributing to instability of orthodontic ... treatment results had long been postulated prior to the quantification of the anterior component of occlusal force by Southard et al in 1989. Many studies

  17. Two-vessel chronic total occlusion. Complete percutaneous revascularisation

    PubMed Central

    Dębski, Artur; Opolski, Maksymilian P.; Kłopotowski, Mariusz; Karcz, Maciej A.; Witkowski, Adam

    2014-01-01

    Little is known about the success rate of second attempts to open chronic total occlusions. Two-vessel occlusion makes the procedure is even more challenging. Thus, embarking on complete percutaneous revascularization of such lesions requires adequate experience, especially after first unsuccessful attempt. We present a case of a 52-year-old male patient in whom successful percutaneous opening of two chronic coronary at staged procedure was performed. PMID:25489332

  18. Digital Artery Occlusion Secondary to Plastic Shopping Bag Trauma

    PubMed Central

    Joy, R; Isaacs, JL; McCarthy, RJ

    2007-01-01

    Upper limb digital arterial occlusion is uncommon. We present the case of a 47-year-old man with an ischaemic right middle finger (dominant hand) due to trauma from carrying a heavy plastic shopping bag. Duplex scanning revealed no proximal source of emboli. An angiogram demonstrated occlusions in the medial and lateral digital arteries of the middle digit at the level of the proximal phalanx. Treatment with heparin and warfarin resulted in complete resolution of symptoms. PMID:18201465

  19. Aortic Balloon Occlusion is Effective in Controlling Pelvic Hemorrhage

    DTIC Science & Technology

    2012-05-08

    of endovascular aortic balloon occlusion, a technique that has been used in the setting of elective and emergent aneurysm repair for many years [8,9... aneurysms [8,9]. A recent technical note from this group provided a fuller description of the technique of compliant balloon selection, insertion...Clamp before you cut: Proximal control of ruptured abdominal aortic aneurysms using endovascular balloon occlusion: Case reports. Vasc Endovasc Surg

  20. Atropine penalisation versus occlusion as the primary treatment for amblyopia

    PubMed Central

    Foley-Nolan, A.; McCann, A.; O'Keefe, M.

    1997-01-01

    AIMS/BACKGROUND—Pharmacological penalisation of non-amblyopic eyes is an infrequently used alternative to occlusion for treating amblyopia. The authors compared the efficacy of atropine penalisation and that of occlusion as a primary treatment for amblyopia.
METHODS—Thirty six newly diagnosed patients with amblyopia were allocated to two groups for treatment. Eighteen patients in each group were treated either with atropine penalisation (group A) or occlusion therapy (group P).
RESULTS—There was a statistically significant improvement in visual acuity in both groups treated. In group A improvement of the geometric mean visual acuity of the amblyopic eye was from 6/50 to 6/11 (p<0.001). In group P improvement of the geometric mean visual acuity was from 6/60 to 6/19 (p<0.001). In group A non-compliance with treatment was only 6% (2/18). Non-compliance in group P was 45% (8/18) at some stages of the treatment. Neither group produced an incidence of occlusion amblyopia.
CONCLUSIONS—In this study atropine penalisation has been shown to be as effective as occlusion therapy in the treatment of amblyopia. Patient acceptance of atropine penalisation was superior to that for occlusion therapy as was shown by the compliance rate. Atropine treatment was also advantageous in that compliance could be readily checked by inspection.

 PMID:9135409

  1. The occlusion spectrum for volume classification and visualization.

    PubMed

    Correa, Carlos D; Ma, Kwan-Liu

    2009-01-01

    Despite the ever-growing improvements on graphics processing units and computational power, classifying 3D volume data remains a challenge.In this paper, we present a new method for classifying volume data based on the ambient occlusion of voxels. This information stems from the observation that most volumes of a certain type, e.g., CT, MRI or flow simulation, contain occlusion patterns that reveal the spatial structure of their materials or features. Furthermore, these patterns appear to emerge consistently for different data sets of the same type. We call this collection of patterns the occlusion spectrum of a dataset. We show that using this occlusion spectrum leads to better two-dimensional transfer functions that can help classify complex data sets in terms of the spatial relationships among features. In general, the ambient occlusion of a voxel can be interpreted as a weighted average of the intensities in a spherical neighborhood around the voxel. Different weighting schemes determine the ability to separate structures of interest in the occlusion spectrum. We present a general methodology for finding such a weighting. We show results of our approach in 3D imaging for different applications, including brain and breast tumor detection and the visualization of turbulent flow.

  2. Occlusion, Orthodontic treatment, and temporomandibular disorders: a review.

    PubMed

    McNamara, J A; Seligman, D A; Okeson, J P

    1995-01-01

    A review of the current literature regarding the interaction of morphologic and functional occlusal factors relative to TMD indicates that there is a relatively low association of occlusal factors in characterizing TMD. Skeletal anterior open bite, overjets greater than 6 to 7 mm, retruded cuspal position/intercuspal position slides greater than 4 mm, unilateral lingual crossbite, and five or more missing posterior teeth are the five occlusal features that have been associated with specific diagnostic groups of TMD conditions. The first three factors often are associated with TMJ arthropathies and may be the result of osseous or ligamentous changes within the temporomandibular articulation. With regard to the relationship of orthodontic treatment to TMD, the current literature indicates that orthodontic treatment performed during adolescence generally does not increase or decrease the odds of developing TMD later in life. There is no elevated risk of TMD associated with any particular type of orthodontic mechanics or with extraction protocols. Although a stable occlusion is a reasonable orthodontic treatment goal, not achieving a specific gnathologically ideal occlusion does not result in TMD signs and symptoms. Thus, according to the existing literature, the relationship of TMD to occlusion and orthodontic treatment is minor. Signs and symptoms of TMD occur in healthy individuals and increase with age, particularly during adolescence; thus, TM disorders that originate during various types of dental treatment may not be related to the treatment but may be a naturally occurring phenomenon.

  3. Suprarenal vena caval occlusion. Principles of operative management.

    PubMed Central

    Smith, B M; Mulherin, J L; Sawyers, J L; Turner, B I; Prager, R L; Dean, R H

    1984-01-01

    Retrohepatic occlusion of the inferior vena cava caused by tumor complicates complete resection and not infrequently is associated with life-threatening symptoms that accelerate the lethality of the underlying malignant process. This report summarizes our experience with caval thrombectomy and reconstruction that allowed complete removal of all gross tumor in seven patients with malignant occlusion of the retrohepatic inferior vena cava. Included in this group are five patients with renal cell carcinoma and extension of tumor into the retrohepatic vena cava. Three of these patients had extension of tumor thrombus into the right atrium. A sixth patient had recurrent right adrenal cortical carcinoma with tumor invasion of the vena cava and occlusion to the right atrium. Associated hepatic vein occlusion and secondary Budd-Chiari syndrome also was successfully managed in this patient. The final patient with occlusion of the entire suprarenal vena cava required caval reconstruction after resection of a primary leiomyosarcoma of the retrohepatic portion of the vena cava. Careful planning of the operative procedure, adequate exposure, complete mobilization of the retrohepatic vena cava, and control of the hepatic venous effluent will allow patients with retrohepatic vena caval occlusions to be managed with safety and success. Images Figs. 1A and B. Fig. 4. Fig. 5. Fig. 6. Fig. 8. PMID:6732311

  4. [Occlusal evaluation and design of dental implant therapy in defect dentition].

    PubMed

    Li, Y

    2016-04-09

    Implant prosthesis of dentition defect is characteristic of remaining teeth and implants exist at the same time, so the remaining teeth occlusal conditions related to the final occlusal design is to maintain, adjust or re-establish the original dentition occlusion. Therefore, full evaluation of remaining teeth occlusion before restoration, clear prognosis, balancing the occlusal force distribution of natural teeth and implants, and carrying out the predictable occlusal design in the entire process of implant prosthesis can minimize the adverse events after implant prosthesis. Based on the typical cases in this paper, three occlusal design types of occlusal maintain-implant restoration, occlusal adjustment-implant restoration and occlusal reconstruction-implant restoration will be expounded respectively.

  5. 49 CFR 238.417 - Side loads.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Side loads. 238.417 Section 238.417 Transportation....417 Side loads. (a) Each passenger car body structure shall be designed to resist an inward transverse load of 80,000 pounds of force applied to the side sill and 10,000 pounds of force applied to the...

  6. Extravasal occlusion of large vessels with titanic clips: efficiency, indications, and contraindications.

    PubMed

    Vasilenko, Yu V; Kim, A I; Kotov, S A

    2002-11-01

    The mechanism of extravasal occlusion of blood vessels with titanic clips "Atrauclip" and "Ligaclip extra" was studied in order to reveal indications and contraindications to their use. Occlusion with the clips of both types was ineffective in vessels with a diameter of >7.0 mm. Arteritis or the presence of an intravascular occlusion facility in the vessel were also the contraindications for clip occlusion. In overcases the procedure of occlusion with titanic clips was efficient and atraumatic.

  7. Leptospirosis and Peripheral Artery Occlusive Disease

    PubMed Central

    Chiu, Chun-Hsiang; Lin, Cheng-Li; Lee, Feng-You; Wang, Ying-Chuan; Kao, Chia-Hung

    2016-01-01

    Abstract Data on the association between peripheral artery occlusive disease (PAOD) and leptospirosis are limited. We conducted a retrospective cohort study for determining whether leptospirosis is one of the possible risk factors for PAOD. Patients diagnosed with leptospirosis by using 2000 to 2010 data from the Taiwan National Health Insurance Research Database. Patients with leptospirosis without a history of PAOD were selected. For each leptospirosis patient, 4 controls without a history of leptospirosis and PAOD were randomly selected and frequency-matched for sex, age, the year of the index date, and comorbidity diseases. The follow-up period was from the time of the initial diagnosis of leptospirosis to the diagnosis date of PAOD, or December 31, 2011. The Cox proportional hazard regression models were used for analyzing the risk of PAOD. During the follow-up period, the cumulative incidence of PAOD was higher among the patients from the leptospirosis cohort than among the nonleptospirosis cohort (log-rank test, P < 0.001). In total, 29 patients with PAOD from the leptospirosis cohort and 81 from the nonleptospirosis cohort were observed with the incidence rates of 2.1 and 1.3 per 1000 person-years, respectively, yielding a crude hazards ratio (HR) of 1.62 (95% confidence interval [CI] = 1.44–1.81) and adjusted HR (aHR) of 1.75 (95% CI = 1.58–1.95). The risk of PAOD was 1.75-fold higher in the patients with leptospirosis than in the general population. PMID:26986166

  8. Detecting and Treating Occlusal Caries Lesions

    PubMed Central

    Stolpe, M.; Meyer-Lueckel, H.; Paris, S.

    2015-01-01

    The health gains and costs resulting from using different caries detection strategies might not only depend on the accuracy of the used method but also the treatment emanating from its use in different populations. We compared combinations of visual-tactile, radiographic, or laser-fluorescence–based detection methods with 1 of 3 treatments (non-, micro-, and invasive treatment) initiated at different cutoffs (treating all or only dentinal lesions) in populations with low or high caries prevalence. A Markov model was constructed to follow an occlusal surface in a permanent molar in an initially 12-y-old male German patient over his lifetime. Prevalence data and transition probabilities were extracted from the literature, while validity parameters of different methods were synthesized or obtained from systematic reviews. Microsimulations were performed to analyze the model, assuming a German health care setting and a mixed public-private payer perspective. Radiographic and fluorescence-based methods led to more overtreatments, especially in populations with low prevalence. For the latter, combining visual-tactile or radiographic detection with microinvasive treatment retained teeth longest (mean 66 y) at lowest costs (329 and 332 Euro, respectively), while combining radiographic or fluorescence-based detections with invasive treatment was the least cost-effective (<60 y, >700 Euro). In populations with high prevalence, combining radiographic detection with microinvasive treatment was most cost-effective (63 y, 528 Euro), while sensitive detection methods combined with invasive treatments were again the least cost-effective (<59 y, >690 Euro). The suitability of detection methods differed significantly between populations, and the cost-effectiveness was greatly influenced by the treatment initiated after lesion detection. The accuracy of a detection method relative to a “gold standard” did not automatically convey into better health or reduced costs. Detection

  9. Contact mechanics of the human finger pad under compressive loads.

    PubMed

    Dzidek, Brygida M; Adams, Michael J; Andrews, James W; Zhang, Zhibing; Johnson, Simon A

    2017-02-01

    The coefficient of friction of most solid objects is independent of the applied normal force because of surface roughness. This behaviour is observed for a finger pad except at long contact times (greater than 10 s) against smooth impermeable surfaces such as glass when the coefficient increases with decreasing normal force by about a factor of five for the load range investigated here. This is clearly an advantage for some precision manipulation and grip tasks. Such normal force dependence is characteristic of smooth curved elastic bodies. It has been argued that the occlusion of moisture in the form of sweat plasticises the surface topographical features and their increased compliance allows flattening under an applied normal force, so that the surfaces of the fingerprint ridges are effectively smooth. While the normal force dependence of the friction is consistent with the theory of elastic frictional contacts, the gross deformation behaviour is not and, for commonly reported values of the Young's modulus of stratum corneum, the deformation of the ridges should be negligible compared with the gross deformation of the finger pad even when fully occluded. This paper describes the development of a contact mechanics model that resolves these inconsistencies and is validated against experimental data.

  10. Dental occlusion influences knee muscular performances in asymptomatic females.

    PubMed

    Grosdent, Stéphanie; O'Thanh, Roseline; Domken, Olivier; Lamy, Marc; Croisier, Jean-Louis

    2014-02-01

    Some authors claim that occlusal appliances can enhance athletic performance. Therefore, this study investigated the influence of dental occlusion on knee muscle strength performance. Twelve healthy female subjects (mean age, 24.1 ± 3.1 years) without temporomandibular joint dysfunction participated in this study. Isokinetic quadriceps and hamstring strength were assessed in relation to 3 randomized jaw conditions: mouth closed in maximum intercuspidation without splint, mouth closed on a balanced splint which optimized contact over the dental arch, mouth closed on a piece of resin of 1 mm which created an imbalanced occlusion. Tests were performed at 60 and 240°·s in concentric and 30°·s in eccentric exertions. Concentric performances did not show any significant difference between the 3 jaw conditions (p > 0.05). In contrast, in the eccentric trials related to quadriceps performance, significant differences (p ≤ 0.05) were observed between the resin condition and the 2 other modalities (without splint or with a balanced splint). The imbalanced occlusion created by the resin component corresponded to an average decrease of 9% in eccentric peak torque. The eccentric hamstring peak torques also showed a significant difference (p ≤ 0.05) between measurements with splint and with resin (7% decrease when occlusion was imbalanced). In conclusion, among asymptomatic females, artificial imbalanced occlusion induces immediate and significant alteration of knee eccentric muscle performances. Therefore, occlusion examination should be undertaken on a regular and frequent basis for high-level athletes. Moreover, for athletes using mouthguards, muscular performance assessments should be planned with and without the dental protection.

  11. Dental occlusion influences knee muscular performances in asymptomatic females.

    PubMed

    Grosdent, Stéphanie; O'Thanh, Roseline; Domken, Olivier; Lamy, Marc; Croisier, Jean-Louis

    2013-09-14

    Some authors claim that occlusal appliances can enhance athletic performance. Therefore this study investigated the influence of dental occlusion on knee muscle strength performance. Twelve healthy female subjects (mean age 24.1 ± 3.1 years) without temporomandibular joint dysfunction participated in this study. Isokinetic quadriceps and hamstring strength were assessed in relation to three randomized jaw conditions: mouth closed in maximum intercuspidation without splint, mouth closed on a balanced splint which optimized contact over the dental arch, mouth closed on a piece of resin of 1 mm which created an imbalanced occlusion. Tests were performed at 60°/s and 240°/s in concentric and 30°/s in eccentric exertions. Concentric performances did not show any significant difference between the 3 jaw conditions (p > 0.05). By contrast, in the eccentric trials related to quadriceps performance, significant differences (p < 0.05) were observed between the resin condition and the two other modalities (without splint or with a balanced splint). The imbalanced occlusion created by the resin component corresponded to an average decrease of 9% in eccentric peak torque. The eccentric hamstring peak torques also showed a significant difference (p < 0.05) between measurements with splint and with resin (7% decrease when occlusion was imbalanced). In conclusion, among asymptomatic females, artificial imbalanced occlusion induces immediate and significant alteration of knee eccentric muscle performances. Therefore, occlusion examination should be undertaken on a regular and frequent basis for high-level athletes. Moreover, for athletes using mouthguards, muscular performance assessments should be planned with and without the dental protection.

  12. Mapping the dynamics of brain perfusion using functional ultrasound in a rat model of transient middle cerebral artery occlusion.

    PubMed

    Brunner, Clément; Isabel, Clothilde; Martin, Abraham; Dussaux, Clara; Savoye, Anne; Emmrich, Julius; Montaldo, Gabriel; Mas, Jean-Louis; Baron, Jean-Claude; Urban, Alan

    2017-01-01

    Following middle cerebral artery occlusion, tissue outcome ranges from normal to infarcted depending on depth and duration of hypoperfusion as well as occurrence and efficiency of reperfusion. However, the precise time course of these changes in relation to tissue and behavioral outcome remains unsettled. To address these issues, a three-dimensional wide field-of-view and real-time quantitative functional imaging technique able to map perfusion in the rodent brain would be desirable. Here, we applied functional ultrasound imaging, a novel approach to map relative cerebral blood volume without contrast agent, in a rat model of brief proximal transient middle cerebral artery occlusion to assess perfusion in penetrating arterioles and venules acutely and over six days thanks to a thinned-skull preparation. Functional ultrasound imaging efficiently mapped the acute changes in relative cerebral blood volume during occlusion and following reperfusion with high spatial resolution (100 µm), notably documenting marked focal decreases during occlusion, and was able to chart the fine dynamics of tissue reperfusion (rate: one frame/5 s) in the individual rat. No behavioral and only mild post-mortem immunofluorescence changes were observed. Our study suggests functional ultrasound is a particularly well-adapted imaging technique to study cerebral perfusion in acute experimental stroke longitudinally from the hyper-acute up to the chronic stage in the same subject.

  13. Efficient minimum error bounded particle resampling L1 tracker with occlusion detection.

    PubMed

    Mei, Xue; Ling, Haibin; Wu, Yi; Blasch, Erik P; Bai, Li

    2013-07-01

    Recently, sparse representation has been applied to visual tracking to find the target with the minimum reconstruction error from a target template subspace. Though effective, these L1 trackers require high computational costs due to numerous calculations for l1 minimization. In addition, the inherent occlusion insensitivity of the l1 minimization has not been fully characterized. In this paper, we propose an efficient L1 tracker, named bounded particle resampling (BPR)-L1 tracker, with a minimum error bound and occlusion detection. First, the minimum error bound is calculated from a linear least squares equation and serves as a guide for particle resampling in a particle filter (PF) framework. Most of the insignificant samples are removed before solving the computationally expensive l1 minimization in a two-step testing. The first step, named τ testing, compares the sample observation likelihood to an ordered set of thresholds to remove insignificant samples without loss of resampling precision. The second step, named max testing, identifies the largest sample probability relative to the target to further remove insignificant samples without altering the tracking result of the current frame. Though sacrificing minimal precision during resampling, max testing achieves significant speed up on top of τ testing. The BPR-L1 technique can also be beneficial to other trackers that have minimum error bounds in a PF framework, especially for trackers based on sparse representations. After the error-bound calculation, BPR-L1 performs occlusion detection by investigating the trivial coefficients in the l1 minimization. These coefficients, by design, contain rich information about image corruptions, including occlusion. Detected occlusions are then used to enhance the template updating. For evaluation, we conduct experiments on three video applications: biometrics (head movement, hand holding object, singers on stage), pedestrians (urban travel, hallway monitoring), and

  14. A framework for retinal layer intensity analysis for retinal artery occlusion patient based on 3D OCT

    NASA Astrophysics Data System (ADS)

    Liao, Jianping; Chen, Haoyu; Zhou, Chunlei; Chen, Xinjian

    2014-03-01

    Occlusion of retinal artery leads to severe ischemia and dysfunction of retina. Quantitative analysis of the reflectivity in the retina is very needed to quantitative assessment of the severity of retinal ischemia. In this paper, we proposed a framework for retinal layer intensity analysis for retinal artery occlusion patient based on 3D OCT images. The proposed framework consists of five main steps. First, a pre-processing step is applied to the input OCT images. Second, the graph search method was applied to segment multiple surfaces in OCT images. Third, the RAO region was detected based on texture classification method. Fourth, the layer segmentation was refined using the detected RAO regions. Finally, the retinal layer intensity analysis was performed. The proposed method was tested on tested on 27 clinical Spectral domain OCT images. The preliminary results show the feasibility and efficacy of the proposed method.

  15. The Hybrid Approach for Intervention of Chronic Total Occlusions.

    PubMed

    Rangan, Bavana V; Kotsia, Anna; Christopoulos, George; Spratt, James; Rinfret, Stephane; Banerjee, Subhash; Brilakis, Emmanouil S

    2015-09-09

    The "hybrid" approach to chronic total occlusion (CTO) percutaneous coronary intervention (PCI) was developed to provide guidance on optimal crossing strategy selection. Dual angiography remains the cornerstone of clinical decision making in CTO PCI. Four angiographic parameters are assessed: (a) morphology of the proximal cap (clear-cut or ambiguous); (b) occlusion length; (c) distal vessel size and presence of bifurcations beyond the distal cap; and (d) location and suitability of location and suitability of a retrograde conduit (collateral channels or bypass grafts) for retrograde access. Antegrade wire escalation is favored for short (<20 mm) occlusions, usually escalating rapidly from a soft tapered-tip polymer-jacketed guidewire to a stiff polymer-jacketed or tapered-tip guidewire. Antegrade dissection/re-entry is favored in long (≥20 mm long) occlusions, trying to minimize the dissection length by re-entering into the distal true lumen immediately after the occlusion. Primary retrograde approach is preferred for lesions with an ambiguous proximal cap, poor distal target, good interventional collaterals, and heavy calcification,as well as chronic kidney disease. The "hybrid" approach advocates early change between strategies to enable CTO crossing in the most efficacious, efficient, and safe way. Several early studies are demonstrating high success and low complication rates with use of the "hybrid" approach, supporting its expanding use in CTO PCI.

  16. Interactions between occlusion and human brain function activities.

    PubMed

    Ohkubo, C; Morokuma, M; Yoneyama, Y; Matsuda, R; Lee, J S

    2013-02-01

    There are few review articles in the area of human research that focus on the interactions between occlusion and brain function. This systematic review discusses the effect of occlusion on the health of the entire body with a focus on brain function. Available relevant articles in English from 1999 to 2011 were assessed in an online database and as hard copies in libraries. The selected 19 articles were classified into the following five categories: chewing and tongue movements, clenching and grinding, occlusal splints and occlusal interference, prosthetic rehabilitation, and pain and stimulation. The relationships between the brain activity observed in the motor and sensory cortices and movements of the oral and maxillofacial area, such as those produced by gum chewing, tapping and clenching, were investigated. It was found that the sensorimotor cortex was also affected by the placement of the occlusal interference devices, splints and implant prostheses. Brain activity may change depending on the strength of the movements in the oral and maxillofacial area. Therefore, mastication and other movements stimulate the activity in the cerebral cortex and may be helpful in preventing degradation of a brain function. However, these findings must be verified by evidence gathered from more subjects.

  17. Mechanism of vaso-occlusion in sickle cell anemia

    NASA Astrophysics Data System (ADS)

    Lei, Huan; Karniadakis, George

    2012-11-01

    Vaso-occlusion crisis is one of the key hallmark of sickle cell anemia. While early studies suggested that the crisis is caused by blockage of a single elongated cell, recent experimental investigations indicate that vaso-occlusion is a complex process triggered by adhesive interactions among different cell groups in multiple stages. Based on dissipative particle dynamics, a multi-scale model for the sickle red blood cells (SS-RBCs), accounting for diversity in both shapes and cell rigidities, is developed to investigate the mechanism of vaso-occlusion crisis. Using this model, the adhesive dynamics of single SS-RBC was investigated in arterioles. Simulation results indicate that the different cell groups (deformable SS2 RBCs, rigid SS4 RBCs, leukocytes, etc.) exhibit heterogeneous adhesive behavior due to the different cell morphologies and membrane rigidities. We further simulate the tube flow of SS-RBC suspensions with different cell fractions. The more adhesive SS2 cells interact with the vascular endothelium and further trap rigid SS4 cells, resulting in vaso-occlusion in vessels less than 15 μm . Under inflammation, adherent leukocytes may also trap SS4 cells, resulting in vaso-occlusion in even larger vessels. This work was supported by the NSF grant CBET-0852948 and the NIH grant R01HL094270.

  18. The Hybrid Approach to Intervention of Chronic Total Occlusions

    PubMed Central

    Rangan, Bavana V.; Kotsia, Anna; Christopoulos, George; Spratt, James; Rinfret, Stephane; Banerjee, Subhash; Brilakis, Emmanouil S.

    2015-01-01

    The “hybrid” approach to chronic total occlusion (CTO) percutaneous coronary intervention (PCI) was developed to provide guidance on optimal crossing strategy selection. Dual angiography remains the cornerstone of clinical decision making in CTO PCI. Four angiographic parameters are assessed: (a) morphology of the proximal cap (clear-cut or ambiguous); (b) oc-clusion length; (c) distal vessel size and presence of bifurcations beyond the distal cap; and (d) location and suitability of a retrograde con-duit (collateral channels or bypass grafts) for retrograde access. Antegrade wire escalation is favored for short (<20 mm) occlusions, usually escalating rapidly from a soft tapered-tip polymer-jacketed guidewire to a stiff polymer-jacketed or tapered-tip guidewire. Antegrade dissection/re-entry is favored in long (≥20 mm long) occlusions, try-ing to minimize the dissection length by re-entering into the distal true lumen immediately after the occlusion. Primary retro-grade approach is preferred for lesions with an ambiguous proximal cap, poor distal target, good interventional collaterals, and heavy calcification, as well as chronic kidney disease. The “hybrid” approach advocates early change between strategies to enable CTO crossing in the most efficacious, efficient, and safe way. Several early studies are demonstrating high success and low complication rates with use of the “hybrid” approach, supporting its expanding use in CTO PCI. .

  19. Systemic abnormalities associated with retinal vein occlusion in young patients

    PubMed Central

    Sinawat, Suthasinee; Bunyavee, Chavisa; Ratanapakorn, Tanapat; Sinawat, Supat; Laovirojjanakul, Wipada; Yospaiboon, Yosanan

    2017-01-01

    Objectives To study the systemic abnormalities associated with retinal vein occlusion in patients aged ≤50 years with a particular emphasis on atherosclerotic diseases and thrombophilic disorders. Methods Medical charts of patients, aged ≤50 years whose diagnoses were retinal vein occlusions during the period 1995–2015 were retrospectively reviewed. The primary outcome was the number of systemic abnormalities associated with these patients. Secondary outcomes included types of retinal vein occlusion and sites of occlusion. Results Atherosclerotic diseases were the most common systemic abnormalities associated with retinal vein occlusion and accounted for 55.1% of the patients in the study. Hypertension in 27.55%, diabetes mellitus in 16.33%, and 5.1% with dyslipidemia were noted. The number of thrombophilic disorders seemed to be less than expected and were noted in only 5.1%. Other systemic abnormalities included viral hepatitis infection, systemic lupus erythematosus, and acquired immunodeficiency syndrome. Oral contraceptives were used by some patients. Conclusion Atherosclerotic diseases remained the most commonly associated systemic diseases in the majority of these patients. Approach to these patients should include a screening for hypertension, diabetes mellitus, and lipid abnormalities. Thrombophilia should also be considered where no obvious atherosclerotic diseases are found or if the patient is <40 years old, a history of thrombosis or a family history of thrombosis is possible. PMID:28260858

  20. Effect of root morphology on biomechanical behaviour of premolars associated with abfraction lesions and different loading types.

    PubMed

    Soares, P V; Souza, L V; Veríssimo, C; Zeola, L F; Pereira, A G; Santos-Filho, P C F; Fernandes-Neto, A J

    2014-02-01

    The aim of this study was to investigate the biomechanical behaviour of maxillary premolar teeth regarding root morphology and abfraction depth, submitted to axial and oblique occlusal load. The investigation was conducted using 3D finite element analysis and strain gauge test. Sound maxillary premolar single and double root were selected for 3D model generation. The teeth were scanned for external morphology data acquisition. The 3D geometry was stored in *.STL and exported to Bio-CAD software (Rhinoceros-3D) to model generation. Mesh generation, mechanical properties and boundary conditions were performed in finite element software (Femap, Noran Engineering, USA). Twelve models were generated: sound tooth, 1.25 and 2.5 mm abfraction teeth. 100N compressive static load was applied: axially and 45° angle to the long axis on the palatine surface of the buccal cusp. Two strain gauges were bonded on the teeth mounted in a mechanical testing machine. Von Mises criterion showed that the double-root teeth associated with 2.5 mm abfraction and oblique loading presented higher stress values. Axial loading associated with single-root teeth propitiated the lowest stress rates. Double root sound 1.25 and 2.5 mm abfraction teeth associated with oblique loading showed the highest strain values (μS): 692.6, 1043.31 and 1236.14, respectively. Single root sound 1.25 and 2.5 mm abfraction teeth associated with oblique loading showed 467.10, 401.51 and 420.98 strain values, respectively. Axial loading showed lower strain rates, ranging from 136.12 to 366.91. The association of deep lesions, oblique loading and double-root tooth promoted higher stress and strain concentration.

  1. Ocean Tide Loading Computation

    NASA Technical Reports Server (NTRS)

    Agnew, Duncan Carr

    2005-01-01

    September 15,2003 through May 15,2005 This grant funds the maintenance, updating, and distribution of programs for computing ocean tide loading, to enable the corrections for such loading to be more widely applied in space- geodetic and gravity measurements. These programs, developed under funding from the CDP and DOSE programs, incorporate the most recent global tidal models developed from Topex/Poscidon data, and also local tide models for regions around North America; the design of the algorithm and software makes it straightforward to combine local and global models.

  2. Gradients of occlusal wear in hunter-gatherers and agriculturalists.

    PubMed

    Deter, Christina A

    2009-03-01

    Occlusal wear was recorded in maxillary teeth from three North American late Archaic (3385 +/- 365 cal BC) hunter-gatherer sites (n = 306) and late Anasazi-early Zuni agricultural sites ( approximately 1300 AD) (n = 87). Comparisons were undertaken using descriptive and inferential statistics to determine differences between these groups, and along the maxillary tooth row. The hunter-gatherers had a significantly greater percentage of occlusal wear than the agriculturalists. For both hunter-gatherers and agriculturalists, occlusal wear was greatest on the central incisors and first molars. The third molars had the least amount of wear. It was inferred from these results that the hunter-gatherers had a more abrasive diet, and different daily task activities compared to the agriculturalists. One further finding was that wear patterns on anterior and posterior teeth are influenced by the order that teeth erupt into the jaw, as well as diet and behavior.

  3. Radiation-induced large intracranial vessel occlusive vasculopathy

    SciTech Connect

    Brant-Zawadzki, M.; Anderson, M.; DeArmond, S.J.; conley, F.K.; Jahnke, R.W.

    1980-01-01

    Two patients who developed large intracranial vessel occlusion after standard radiation therapy for brain tumor are described. This form of vascular occlusion is usually seen in patients who have previously been treated by radiotherapy for intracranial tumor who then develop a relatively acute change in neurologic status. Histology of the lesion mimics accelerated focal arteriosclerosis. The clinical and radiographic manifestations of one case were highly atypical. The vasculopathy became evident shortly after termination of radiation therapy for a fourth ventricular ependymoma, and the angiographic picture stimulated a diffuse arteritis. The second patient was more typical, with clinical symptoms developing 12 years after radiation therapy for an oligodendroglioma. Occlusion of a proximal vessel that had been included in the radiation port was demonstrated radiographically and confirmed by pathologic examination. The clinical, angiographic, and histologic features of these two cases are discussed and previously reported cases are reviewed.

  4. Chronic vascular reactions to steel coil occlusion devices.

    PubMed

    Barth, K H; Strandberg, J D; Kaufman, S L; White, R I

    1978-09-01

    Original Gianturco steel coil vascular embolization devices and two modifications were compared for their occlusive effects and for the degree of adverse reaction in the surrounding vessel wall. Modifications consisted of silk or Ivalon replacing the wool strands of the original device. Single coils were placed into the left renal artery of nine mixed breed swine and restudied 3 months later. The bare coils did not occlude the vessels nor lead to significant foreign body reaction. Wool, silk, and Ivalon coils produced prompt and sustained renal artery occlusion. Upon histologic examination of the vessel wall, foreign body and chronic inflammatory reaction was found to be strongest against wool. This reaction was less with silk and markedly diminished with Ivalon. The results indicate that silk and Ivalon coils, while having the same occlusive effect, are preferable to wool coils if less local reaction is desired.

  5. A pharmacological approach in newly established retinal vein occlusion model

    PubMed Central

    Fuma, Shinichiro; Nishinaka, Anri; Inoue, Yuki; Tsuruma, Kazuhiro; Shimazawa, Masamitsu; Kondo, Mineo; Hara, Hideaki

    2017-01-01

    The mechanism underlying the effects of anti-vascular endothelial growth factor (VEGF) antibody in retinal vein occlusion (RVO) treatment is poorly understood, partly due to the lack of RVO animal models that mimic clinical pathology. The aims of this study were to establish a suitable RVO model, clarify the pathogenic mechanisms, and evaluate the effects of anti-VEGF antibody in the model. Mouse retinal veins were occluded by laser photocoagulation after rose bengal injection. Reduction of the b/a wave amplitude ratio, retinal nonperfusion, cystoid edema, and hard exudates were observed after occlusion, and expression of RVO-related genes was altered. Administration of anti-VEGF antibody immediately, or 7 days, after occlusion resulted in reduction and increase of the nonperfused area, respectively. We conclude that the present model will be useful for clarification of the pathogenic mechanisms, and that the timing of anti-VEGF antibody administration is important for the successful amelioration of retinal nonperfusion. PMID:28252108

  6. Transcatheter vessel occlusion: angiographic results versus clinical success

    SciTech Connect

    Feldman, L.; Greenfield, A.J.; Waltman, A.C.; Novelline, R.A.; Van Breda, A.; Luers, P.; Athanasoulis, C.A.

    1983-04-01

    A review was made of 219 transcatheter vessel occlusion procedures performed over a ten-year period for control of hemorrhage, tumor palliation, or blood supply redistribution prior to intra-arterial chemotherapy. Complete angiographic success was obtained in 85% of the procedures, with partial success in 8%; complete clinical success was achieved in 53% of patients, with partial success in 23%. the most satisfactory clinical results were obtained with hemorrhagic gastritis and pelvic trauma. Embolizations for duodenal ulcer hemorrhage and transhepatic variceal occlusion were the least clinically successful, although isobutyl-cyanoacrylate appeared to be a significant improvement in angiographic therapy for duodenal ulcer. The overall complication rate was 13%, with one third of the complications clinically silent. These results indicate that transcatheter vessel occlusion is a relatively safe and effective method for control of hemorrhage or tumor infarction.

  7. Ambient Occlusion Effects for Combined Volumes and Tubular Geometry

    PubMed Central

    Schott, Mathias; Martin, Tobias; Grosset, A.V. Pascal; Smith, Sean T.; Hansen, Charles D.

    2013-01-01

    This paper details a method for interactive direct volume rendering that computes ambient occlusion effects for visualizations that combine both volumetric and geometric primitives, specifically tube-shaped geometric objects representing streamlines, magnetic field lines or DTI fiber tracts. The algorithm extends the recently presented the directional occlusion shading model to allow the rendering of those geometric shapes in combination with a context providing 3D volume, considering mutual occlusion between structures represented by a volume or geometry. Stream tube geometries are computed using an effective spline-based interpolation and approximation scheme that avoids self-intersection and maintains coherent orientation of the stream tube segments to avoid surface deforming twists. Furthermore, strategies to reduce the geometric and specular aliasing of the stream tubes are discussed. PMID:23559506

  8. [The role of occlusion and extraction in orthodontics. Historical overview].

    PubMed

    Kucsera, Agnes; Struhár, Gabriella

    2012-03-01

    Occlusion is important in each unit of dentistry. The authors describe not only the meaning of normal occlusion and dysgnathy but also the historical background focusing on the most important orthodontists, their achievements and literary works. This article gives an overview of the development of orthodontics from the very beginning (ancient times) to nowadays. The most important figures of these periods are: P. Fauchard, F. C. Kneisel, E. H. Angle, C. Case (dark ages); C. F. Ballard, P. R. Begg, C. H. Tweed (golden ages); L. F. Andrews and R. H. Roth (contemporary period). Along these three eras development and changing of the extraction-principles are shown. Nowadays the orthodontists still use Angle's classification and orthodontic treatment with extraction is also accepted. However it is not a separate treatment method, but only used as complement treatment. The authors stress on the importance of normal occlusion, which should be result of every orthodontic, but also prothetic and gnathological treatment.

  9. Hemi-central retinal artery occlusion in young adults.

    PubMed

    Rishi, Pukhraj; Rishi, Ekta; Sharma, Tarun; Mahajan, Sheshadri

    2010-01-01

    Amongst the clinical presentations of retinal artery occlusion, hemi-central retinal artery occlusion (Hemi-CRAO) is rarely described. This case series of four adults aged between 22 and 36 years attempts to describe the clinical profile, etiology and management of Hemi-CRAO. Case 1 had an artificial mitral valve implant. Polycythemia and malignant hypertension were noted in Case 2. The third patient had Leiden mutation while the fourth patient had Eisenmenger's syndrome. Clinical examination and fundus fluorescein angiography revealed a bifurcated central retinal artery at emergence from the optic nerve head, in all cases. Color Doppler examination of the central retinal artery confirmed branching of the artery behind the lamina cribrosa. It is hypothesized that bifurcation of central retinal artery behind the lamina cribrosa may predispose these hemi-trunks to develop an acute occlusion if associated with underlying risk factors. The prognosis depends upon arterial recanalisation and etiology of the thromboembolic event.

  10. The possible effect of periodontal diseases on occlusal function.

    PubMed

    Rosenbaum, R S

    1993-01-01

    This paper raises new questions about the relationship between occlusion and periodontics. Specifically, it raises questions about the effect of periodontal diseases on mechanoreceptors in the periodontal ligament. Periodontal mechanoreceptors transmit information from the periodontium to various reflexes coordinated by the central nervous system. One of these reflexes is the trigemino-neck reflex. Its function is to change the position of the head, neck, and jaws on a moment-to-moment basis, and it powerfully influences the occlusal position. This paper raises questions about the consequences of periodontal diseases on all reflexes that depend on periodontal mechanoreceptors, and specific questions are raised about the effect of periodontal disease on the trigemino-neck reflex because of its extreme importance to the way we analyze and treat occlusion.

  11. Occlusion spectroscopy as a new paradigm for noninvasive blood measurements

    NASA Astrophysics Data System (ADS)

    Fine, Ilya; Fikhte, Boris; Shvartsman, Leonid D.

    2001-06-01

    We prove experimentally that RBC aggregation is among the major factors affecting time evolution of light transmission in both the normal situation of pulsatile blood flow and the situation of over-systolic vessel occlusion. Optical transmissions of tissue in vivo have been measured in red/near-infrared region. Sudden blood flow cessation causes the light transmission rising. For certain wavelengths range this growth becomes non-monotonic. The correspondence between in vivo measurements and the theoretical simulations is reached if we attribute the transmission growth to the change of average size of scatterers. The most important blood parameters such as hemoglobin, glucose, oxygen saturation, etc., influence the transmission growth following over-systolic occlusion and, therefore, may be extracted from the detailed analysis of the time evolution of optical transmission. It forms a basis for new kind of non-invasive measurements, i.e., occlusion spectroscopy. The results of in vivo clinical trials are presented for glucose and hemoglobin.

  12. Low-intensity exercise, vascular occlusion, and muscular adaptations.

    PubMed

    Teramoto, Masaru; Golding, Lawrence A

    2006-01-01

    The study investigated the effects of low-intensity exercise on muscular fitness when combined with vascular occlusion. Nineteen college male and female students performed two sets of a 5-min step exercise using a 12-inch bench three times per week for 5 weeks. During the step exercise, blood flow to one leg was restricted (vascular occlusion) with a blood pressure cuff, while the other leg was not occluded. Muscular strength of the occluded leg was significantly increased over the nonoccluded leg (p < 0. 05). Muscular endurance and muscle mass were improved after 5 weeks of training (p < 0.05); however, the changes between the two legs were not significantly different (p > 0.05). Exercise with vascular occlusion has the potential to be an alternative form of training to promote muscular strength.

  13. Management of Retinal Vein Occlusion, Who Is Responsible?

    PubMed

    Aghamirsalim, Mohamadreza; Sorbi, Reza; Naderian, Mohammadreza; Cugati, Sudha; Shahsuvaryan, Marianne Levon; Ghazizadeh Hashemi, Maryam

    2016-11-01

    Retinal vein occlusion (RVO) is a common retinal vascular occlusive disorder and is associated with a variety of systemic risk factors. The aim of this study was to investigate whether the underlying diseases were evaluated and managed appropriately by ophthalmologists. We performed a study of 1344 patients with retinal vein occlusion (RVO). Patients were evaluated with a questionnaire including ten closed questions to determine whether ophthalmologists evaluated and informed their patients about the underlying systemic diseases. None of the patients' homocysteine levels were measured. Only a small percentage of the patients were asked about the history of thrombotic diseases or family history of thrombotic diseases. We believe that most ophthalmologists are still not entirely convinced of their responsibility of managing the underlying predisposing factors of RVO. Ophthalmologists should either manage or engage other healthcare providers in the management of RVO to guarantee the patient the best care.

  14. LOADING DEVICE

    DOEpatents

    Ohlinger, L.A.

    1958-10-01

    A device is presented for loading or charging bodies of fissionable material into a reactor. This device consists of a car, mounted on tracks, into which the fissionable materials may be placed at a remote area, transported to the reactor, and inserted without danger to the operating personnel. The car has mounted on it a heavily shielded magazine for holding a number of the radioactive bodies. The magazine is of a U-shaped configuration and is inclined to the horizontal plane, with a cap covering the elevated open end, and a remotely operated plunger at the lower, closed end. After the fissionable bodies are loaded in the magazine and transported to the reactor, the plunger inserts the body at the lower end of the magazine into the reactor, then is withdrawn, thereby allowing gravity to roll the remaining bodies into position for successive loading in a similar manner.

  15. Optical coherence tomography for imaging of chronic total occlusions

    NASA Astrophysics Data System (ADS)

    Munce, Nigel R.; Yang, Victor X. D.; Qiang, Beiping; Courtney, Brian K.; Brzozowski, Lukasz; Bakueva, Ludmilla; Mao, Linda Y.; Standish, Beau; Butany, Jagdish; Dick, Alexander J.; Strauss, Bradley H.; Wright, Graham A.; Vitkin, Alex

    2005-09-01

    Chronic total occlusions (CTOs) are defined as complete occlusions of an artery older than one month. Minimally invasive catheter-based interventions commonly employed for partial occlusions (e.g., balloon angioplasty followed by stenting) are problematic in CTOs because of the phycisian's inability to pass the device through the occlusion without a significant risk of arterial wall perforations. Furthermore, successfully treated CTOs exhibit a high re-occlusion rate. As a result, these cases are mostly sent to bypass surgery. With the advent of drug-eluting stents that reduce the incidence of re-occlusion, and thus, eliminating the second problem, new devices have begun to emerge that aim to recanalize CTOs without the cost and trauma of bypass surgery. These devices, however, need effective image guidance methods to ensure successful crossing of the CTOs. Optical coherence tomography (OCT) is being evaluated as an intravascular imaging modality for guiding catheter-based interventions of CTOs. Occluded ex vivo human arterial samples were used to produce longitudinal cross-sections using an OCT system. These OCT images were compared with histology to assess OCT's ability to identify different components of the occluded artery, evaluate the imaging depth, and determine the ability to detect the underlying vessel wall. Given the inherent difficulties of creating a mechanically scanning OCT probe in the distal tip of a catheter for use in a stenotic artery, we directed our initial efforts towards developing a "motionless" fiber based OCT system using a single mode fiber array. We discuss design considerations for implementing a forward viewing intravascular OCT probe.

  16. Left atrial appendage occlusion: A better alternative to anticoagulation?

    PubMed Central

    Akin, Ibrahim; Nienaber, Christoph A

    2017-01-01

    Non-valvular atrial fibrillation is associated with a significantly increased risk of embolic stroke due to blood clot forming predominantly in the left atrial appendage (LAA). Preventive measures to avoid embolic events are permanent administration of anticoagulants or surgical closure of the LAA. Various clinical trials provide evidence about safety, effectiveness and therapeutic success of LAA occlusion using various cardiac occluder devices. The use of such implants for interventional closure of the LAA is likely to become a valuable alternative for stroke prevention, especially in patients with contraindication for oral anticoagulation as safety, clinical benefit and cost-effectiveness of LAA occlusion has recently been demonstrated. PMID:28289527

  17. A Case of Branch Retinal Artery Occlusion following Uneventful Phacoemulsification

    PubMed Central

    Dragnev, Daniel; Barr, Dai; Kulshrestha, Manoj; Shanmugalingam, Sinnathamboo

    2013-01-01

    We would like to present a case of branch retinal artery occlusion following uneventful phacoemulsification, possibly caused by sub-Tenon's anaesthesia. There were no predisposing general health problems. There are two possible mechanisms: (1) mechanical effect of the bolus anaesthetic; (2) pharmacologically mediated changes in the vascular calibre. The latter mechanism is much more probable, because of the vasoconstrictive properties of both medications used. This is the first reported case of branch retinal artery occlusion after sub-Tenon's anaesthesia with preservative-free medications. PMID:23626570

  18. Pulmonary veno-occlusive disease in a female gardener.

    PubMed

    Rodríguez Rodríguez, Paula; Pedraza Serrano, Fernando; Morán Caicedo, Liliana Patricia; Rodríguez de Guzmán, Maria Carmen; Cebollero Presmanes, María; de Miguel Díez, Javier

    2014-01-01

    Pulmonary veno-occlusive disease (PVOD) is a subgroup of pulmonary arterial hypertension with a poor prognosis. The diagnosis is usually delayed and treatment options other than lung transplantation are unfortunately limited. We report the case of 51-year-old female gardener diagnosed with PVOD by open lung biopsy before her death. Although there are many reported cases of hepatic veno-occlusive disease due to toxic agents present in nature, such as pyrrolizidine alkaloid exposure, to date this has not been linked to PVOD.

  19. Pathogenesis of veno-occlusive liver disease after radiation

    SciTech Connect

    Fajardo, L.F.; Colby, T.V.

    1980-11-01

    Radiation-induced liver disease is characterized structurally by progressive fibrous obliteration of central veins (veno-occlusive disease (VOD)). The pathogenesis is unknown. Samples of liver from 11 patients with radiation-induced VOD were studied by light and electron microscopy for evidence of central vein thrombosis. The patients had received fractionated radiation with total doses of 1850 to 4050 rads, or single doses of 1000 rads. In addition, six patients had received chemotherapy. We postulate that ionizing radiation injures preferentially the endothelial cells of central veins, which leads to focal deposition of fibrin. The resulting fibrin network is eventually replaced by collagen, causing fibrous occlusion.

  20. Stent-based mechanical thrombectomy in acute basilar artery occlusion.

    PubMed

    Cohen, José E; Leker, Ronen R; Moscovici, Samuel; Attia, Moshe; Itshayek, Eyal

    2011-12-01

    Stent-based mechanical thrombectomy was recently proposed as an effective alternative to other mechanical techniques to achieve recanalization of large-vessel embolic occlusions in the anterior circulation. To our knowledge, there are no reports of the use of this technique in acute basilar artery occlusion (ABAO). We present a patient with complete endovascular recanalization of ABAO using a stent-based thrombectomy technique. Advantages and limitations of this technique in the management of ABAO are discussed. The stent-thrombectomy technique is promising, and will need further evaluation in posterior circulation stroke.

  1. Racial differences in the distribution of anterior circulation occlusive disease.

    PubMed

    Gorelick, P B; Caplan, L R; Hier, D B; Parker, S L; Patel, D

    1984-01-01

    We compared clinical and angiographic features of 26 white and 45 black patients with symptomatic occlusive cerebrovascular disease. White patients had more transient ischemic attacks, carotid bruits, and more severe occlusive disease of the internal carotid artery origin. Blacks had more severe disease of the middle cerebral artery stem and supraclinoid internal carotid arteries. Differences were not explained by racial differences in the prevalence of hypertension, diabetes, hypercholesterolemia, or ischemic heart disease. Since the middle cerebral artery lesions in blacks do not correlate with other accepted epidemiologic, clinical, and laboratory markers of atherosclerosis, the lesions may arise from a disorder that differs from atherosclerosis.

  2. Visualisation of urban airborne laser scanning data with occlusion images

    NASA Astrophysics Data System (ADS)

    Hinks, Tommy; Carr, Hamish; Gharibi, Hamid; Laefer, Debra F.

    2015-06-01

    Airborne Laser Scanning (ALS) was introduced to provide rapid, high resolution scans of landforms for computational processing. More recently, ALS has been adapted for scanning urban areas. The greater complexity of urban scenes necessitates the development of novel methods to exploit urban ALS to best advantage. This paper presents occlusion images: a novel technique that exploits the geometric complexity of the urban environment to improve visualisation of small details for better feature recognition. The algorithm is based on an inversion of traditional occlusion techniques.

  3. See-through integral imaging display with background occlusion capability.

    PubMed

    Yamaguchi, Yuta; Takaki, Yasuhiro

    2016-01-20

    Background occlusion capability is provided to a flat-panel-type integral imaging display that has a transparent screen and can superimpose three-dimensional (3D) images on real scenes. A symmetric integral imaging system that comprises two integral imaging systems connected by an additional lens array, is proposed. Elementary images are displayed on a flat-panel display on one integral imaging system to generate 3D images, and the occlusion mask patterns are displayed on a flat-panel display on the other integral imaging system to selectively block rays from background scenes. The proposed system was constructed and experimentally verified.

  4. Relationship between habitual occlusal position and flat bite plane induced occlusal position in volunteers with and without temporomandibular joint sounds.

    PubMed

    Torii, Kengo; Chiwata, Ichiro

    2005-01-01

    The aim of this study was to assess whether temporomandibular joint (TMJ) sounds are associated with the difference between the habitual occlusal position (HOP) and the bite plane induced occlusal position (BPOP). Fifteen dental technician school students who had complete natural dentition, normal occlusion and who exhibited TMJ sounds were compared with fifteen healthy control subjects. HOP was recorded by voluntary jaw closing while in an upright position, and BPOP was recorded after wearing an anterior bite plane for a short period of time. Three interocclusal records were obtained in both positions with a vinyl polysiloxane material, and the recorded maxillomandibular relations were analyzed three-dimensionally and compared. Subjects with TMJ sounds had statistically larger differences between HOP and BPOP than controls (p<.05). Within this study population, an association was found between TMJ sounds and the difference between HOP and BPOP.

  5. Carbohydrate Loading.

    ERIC Educational Resources Information Center

    Csernus, Marilyn

    Carbohydrate loading is a frequently used technique to improve performance by altering an athlete's diet. The objective is to increase glycogen stored in muscles for use in prolonged strenuous exercise. For two to three days, the athlete consumes a diet that is low in carbohydrates and high in fat and protein while continuing to exercise and…

  6. Variable response load limiting device

    NASA Technical Reports Server (NTRS)

    Mcsmith, Dwight D. (Inventor)

    1988-01-01

    An energy absorbing device used as a load limiting member in a structure to control its response to applied loads is described. It functions by utilizing a spool assembly having flanged ends and an interior cavity of sufficiently large diameter to cause it to deform plastically at a prescribed load. In application, the spool is utilized as a pivot point for the legs of an airplane seat. When properly designed and integrated into the seat arrangement the spool will twist about its axis, deforming plastically when the impact load exceeds the spool yield value. Through this deformation, the spool absorbs the kinetic energy of the movement of the seat at a substantially constant rate, thereby controlling the level of loads transmitted to the seat occupant. By proper sizing and collection of materials, it is possible to control load response in a predictable manner.

  7. Long-term pretreatment with desethylamiodarone (DEA) or amiodarone (AMIO) protects against coronary artery occlusion induced ventricular arrhythmias in conscious rats.

    PubMed

    Morvay, Nikolett; Baczkó, István; Sztojkov-Ivanov, Anita; Falkay, György; Papp, Julius Gy; Varró, András; Leprán, István

    2015-09-01

    The aim of this investigation was to compare the effectiveness of long-term pretreatment with amiodarone (AMIO) and its active metabolite desethylamiodarone (DEA) on arrhythmias induced by acute myocardial infarction in rats. Acute myocardial infarction was induced in conscious, male, Sprague-Dawley rats by pulling a previously inserted loose silk loop around the left main coronary artery. Long-term oral pretreatment with AMIO (30 or 100 mg·(kg body mass)(-1)·day(-1), loading dose 100 or 300 mg·kg(-1) for 3 days) or DEA (15 or 50 mg·kg(-1)·day(-1), loading dose 100 or 300 mg·kg(-1) for 3 days), was applied for 1 month before the coronary artery occlusion. Chronic oral treatment with DEA (50 mg·kg(-1)·day(-1)) resulted in a similar myocardial DEA concentration as chronic AMIO treatment (100 mg·kg(-1)·day(-1)) in rats (7.4 ± 0.7 μg·g(-1) and 8.9 ± 2.2 μg·g(-1)). Both pretreatments in the larger doses significantly improved the survival rate during the acute phase of experimental myocardial infarction (82% and 64% by AMIO and DEA, respectively, vs. 31% in controls). Our results demonstrate that chronic oral treatment with DEA resulted in similar cardiac tissue levels to that of chronic AMIO treatment, and offered an equivalent degree of antiarrhythmic effect against acute coronary artery ligation induced ventricular arrhythmias in conscious rats.

  8. Evaluation of the effect of two different occlusal splints on maximum occlusal force in patients with sleep bruxism: a pilot study

    PubMed Central

    Dogan, Arife; Bek, Bulent

    2014-01-01

    PURPOSE The occlusal splint has been used for many years as an effective treatment of sleep bruxism. Several methods have been used to evaluate efficiency of the occlusal splints. However, the effect of the occlusal splints on occlusal force has not been clarified sufficiently. The purpose of this study was to evaluate the effect of occlusal splints on maximum occlusal force in patients with sleep bruxism and compare two type of splints that are Bruxogard-soft splint and canine protected hard stabilization splint. MATERIALS AND METHODS Twelve students with sleep bruxism were participated in the present study. All participants used two different occlusal splints during sleep for 6 weeks. Maximum occlusal force was measured with two miniature strain-gage transducers before, 3 and 6 weeks after insertion of occlusal splints. Clinical examination of temporomandibular disorders was performed for all individuals according to the Craniomandibular Index (CMI) before and 6 weeks after the insertion of splints. The changes in mean occlusal force before, 3 and 6 weeks after insertion of both splints were analysed with paired sample t-test. The Wilcoxon test was used for the comparison of the CMI values before and 6 weeks after the insertion of splints. RESULTS Participants using stabilization splints showed no statistically significant changes in occlusal force before, 3, and 6 weeks after insertion of splint (P>.05) and participants using Bruxogard-soft splint had statistically significant decreased occlusal force 6 weeks after insertion of splint (P<.05). There was statistically significant improvement in the CMI value of the participants in both of the splint groups (P<.05). CONCLUSION Participants who used Bruxogard-soft splint showed decreases in occlusal force 6 weeks after insertion of splint. The use of both splints led to a significant reduction in the clinical symptoms. PMID:24843394

  9. Effect of Occlusal Splints on the Temporomandibular Disorders, Dental Wear and Anxiety of Bruxist Children

    PubMed Central

    Restrepo, Claudia C.; Medina, Isabel; Patiño, Isabel

    2011-01-01

    Objectives: To evaluate the effectiveness of occlusal splints to reduce the signs and symptoms of temporomandibular disorders (TMD), dental wear and anxiety in a group of bruxist children. Methods: All of the subjects were 3 to 6 years old, had complete primary dentition, class I occlusion and were classified as bruxist according to the minimal criteria of the ICSD for bruxism. For each child, anxiety was evaluated with the Conners’ Parent Rating Scales (CPRS). The TMD were evaluated using the RDC/TMD. The dental wear was processed in digital format with Mat Lab® and Lab view® software to determine its size and form. The children were randomized into an experimental (n=19) and a control (n=17) group. The children in the experimental group used rigid bite plates for a two-year period, until mixed dentition. Afterwards, the CPRS and the RDC/TMD were applied again and dental casts were taken. Comparisons of the variables regarding dental wear, signs and symptoms of TMD and anxiety before and after treatment among the groups were analyzed using the t-test, the Wilcoxon rank sum test and the Mann-Whitney test. Results: The subjects in the experimental group showed no statistically significant difference regarding anxiety levels and dental wear when compared with the control group. The signs and symptoms of TMD were not reduced except for the deviation in mouth opening. Conclusions: The use of rigid occlusal bite plates was not efficient in reducing the signs of bruxism as a whole but did reduce the deviation in mouth opening. PMID:21912500

  10. Role of Brushing and Occlusal Forces in Non-Carious Cervical Lesions (NCCL)

    PubMed Central

    Sadaf, Durre; Ahmad, Zubair

    2014-01-01

    Objective: To assess the association of occlusal forces and brushing with non-carious cervical lesions (NCCL). Methodology: It was a Cross-sectional study. The study was conducted in Dental clinics, Department of Surgery, The Aga Khan University Hospital Karachi. The study duration was from 1st January 2009 to 28th Feb 2009. Ninety patients visiting dental clinic were examined clinically. Presence of Non- carious cervical lesions, broken restorations, fractured cusps, presence of occlusal facets, brushing habits, Para functional habits were assessed. All the relevant information and clinical examination were collected on a structured Performa and was analyzed using SPSS version 14.0. . Chi square χ2 test was applied to assess association among different categorical variables. Result: Twenty three (26%) females and 67 (74%) males were included in the study. Thirty five of them (38.9%) were found to have Non-carious cervical lesions. Presence of NCCL has no association with gender (P value 0.458). A significant association was found between NCCL and teeth sensitivity (P value 0.002).The association between use of hard tooth brush and Non-carious cervical lesions was found significant (P value <0.001). However the association among Non-carious cervical lesions and fractured cups, broken restoration, teeth grinding, jaw clenching, pan chalia chewing and frequency of teeth brushing were insignificant. Conclusion: Hard tooth brushing and teeth sensitivity have significant association with Non-carious cervical lesions. The role of occlusal wear in the formation of NCCL is not significant. PMID:25598758

  11. Endovascular Mechanical Recanalisation of Acute Carotid-T Occlusions: A Single-Center Retrospective Analysis

    SciTech Connect

    Fesl, Gunther; Wiesmann, Martin; Patzig, Maximilian; Holtmannspoetter, Markus; Pfefferkorn, Thomas; Dichgans, Martin; Brueckmann, Hartmut

    2011-04-15

    Purpose: Acute carotid-T occlusion generally responds poorly to thrombolysis. Endovascular mechanical thrombectomy (EMT) seems to be a promising alternative. However, there are few data on EMT in carotid-T occlusions. Materials and Methods: We reviewed data of 14 consecutive patients with acute carotid-T occlusions treated with mechanical recanalisation devices. A clot separation/aspiration system was used in 11 patients; different other mechanical retriever devices were used in seven patients; and stents were used in four patients. Modified Rankin Scale scores at 90 days were recorded to assess functional outcome. Results: Six women and eight men were included in the study. Mean patient age was 59.2 years; median National Institute of Health Stroke Scale score on admission was 19; and mean time to treatment was 4.2 h. Successful recanalisation (Thrombolysis in Myocardial Infarction [TIMI] score II and III) was achieved in 11 patients (78.6%). Seven patients (50.0%) were treated with more than one device, leading to successful recanalisation in six of these patients (85.7%). Subarachnoid haemorrhage and large space-occupying bleedings occurred in one (7.1%) and three (21.4%) patients, respectively. At follow-up, three patients (21.4%) were functionally independent, and six (42.9%) had died. Conclusion: When applying different mechanical devices, we found a high recanalisation rate. However, discrepancy between recanalisation and clinical outcome remained. More data are needed to assess the effect of the different methods on the prognoses of stroke patients.

  12. Major vessel occlusion may predict subtherapeutic anticoagulation intensity and feasibility of administration of intravenous thrombolytics

    PubMed Central

    Chang, Jun Young; Jung, Seunguk; Park, Hyun

    2017-01-01

    Objective We investigated the association between the presence of major vessel occlusion (MVO) and the intensity of the International Normalized Ratio (INR) in cardioembolic high-risk patients taking warfarin. We also evaluated whether the presence of MVO could predict the subtherapeutic range of INR ≤1.7 ensuring safe administration of intravenous thrombolytics. Methods The medical records of 177 cardioembolic stroke patients who were taking warfarin between April, 2008 and March, 2015 were retrospectively analyzed. Logistic regression analysis was performed to calculate the odds ratios (ORs) and 95% confidence intervals (95% CIs) for the association between vessel occlusion and intensity of INR. To predict INR ≤1.7, decision tree analysis was performed. Results INR was inversely associated with MVO in an unadjusted model (OR, 0.36; 95% CI, 0.17–0.76), and in a model adjusted for initial NIHSS score and time from symptom onset to arrival (OR, 0.28; 95% CI, 0.11–0.73). Fifty-two of 58 (89.7%) patients with MVO had an INR ≤1.7, compared with 83 of 119 (69.7%) patients without MVO. Indication for anticoagulation agent use was dichotomized into NVAF and others, and applied to the subgroup of patients with MVO. All patients with NVAF (31/31, 100%) had INR ≤1.7, while 21 of 27 of the other patients (77.8%) had INR ≤1.7. Conclusions Low INR at presentation in cardioembolic stroke patients during anticoagulation treatment was associated with occurrence of major vessel occlusive stroke. Presence of MVO and indications for anticoagulation may be utilized to ensure the feasibility of administration of intravenous thrombolytics. PMID:28158211

  13. Modification of polyurethane to reduce occlusion of enteral feeding tubes

    SciTech Connect

    Gaither, Kari A.; Tarasevich, Barbara J.; Goheen, Steven C.

    2009-04-27

    Feeding tubes are used to supply nutritional formula to immobilized patients. The most common cause for failure of enteral feeding tubes is their occlusion. The purpose of this study was to examine whether occlusion of enteral feeding tubes could be minimized using an additive. An open, intermittent enteral feeding system was simulated in the laboratory and data was collected over a period ranging from 2 to 6 days. Feeding formula was cycled through a feeding tube in either the presence or absence of simulated gastric acid in an effort to generate a reproducible occlusion. Pressures in the tube were measured frequently throughout these cycles. We observed pressure spikes with each cycle, but never a complete occlusion. Pressure spikes formed only when simulated gastric acid was mixed with the feeding solution. Large amounts of feeding formula adsorbed onto polyurethane surfaces in the presence of gastric acid. The maximum pressure was reduced by about half from 2.0 psi to 0.8 psi when polyvinyl alcohol (PVA) was added. The addition of PVA to polyurethane also reduced the contact angle from 83° (untreated) to approximately 64° in the presence of PVA. Furthermore, when formula was added to polyurethane in the presence of PVA the thickness of the layer that remained on the surface was almost 10 times greater in controls than on PVA-treated surfaces. These results suggest that a treatment that increases the hydrophilicity of the feeding tube may help minimize clogging.

  14. Efficient Detection of Occlusion prior to Robust Face Recognition

    PubMed Central

    Dugelay, Jean-Luc

    2014-01-01

    While there has been an enormous amount of research on face recognition under pose/illumination/expression changes and image degradations, problems caused by occlusions attracted relatively less attention. Facial occlusions, due, for example, to sunglasses, hat/cap, scarf, and beard, can significantly deteriorate performances of face recognition systems in uncontrolled environments such as video surveillance. The goal of this paper is to explore face recognition in the presence of partial occlusions, with emphasis on real-world scenarios (e.g., sunglasses and scarf). In this paper, we propose an efficient approach which consists of first analysing the presence of potential occlusion on a face and then conducting face recognition on the nonoccluded facial regions based on selective local Gabor binary patterns. Experiments demonstrate that the proposed method outperforms the state-of-the-art works including KLD-LGBPHS, S-LNMF, OA-LBP, and RSC. Furthermore, performances of the proposed approach are evaluated under illumination and extreme facial expression changes provide also significant results. PMID:24526902

  15. The Bacterial Flora of Incipient Occlusal Lesions in Naval Recruits.

    DTIC Science & Technology

    1980-07-01

    prophylaxis to reduce smooth surface plaque was performed on all exposed tooth surfaces using sterile pumice and a bristle brush. Special emphasis was placed...sample tooth’s occlusal surface were swabbed with Lugol’s solution for a period of one minute. Sterile water was used to remove the pumice and iodine

  16. Head movements in the occlusal phase of mastication.

    PubMed

    Matsubara, Nozomu; Hisano, Masataka; Minakuchi, Shunsuke; Soma, Kunimichi

    2002-03-01

    It has been recognized that mandibular movements evoke head movements during jaw tapping. However there have been only a few studies that investigated the aspects of head movements during mastication. The objective of this study was to demonstrate the hypothesis that the head moves actively in mastication in order to achieve effective destruction of a food bolus. Head and mandibular movements during gum, gummi candies and kelp chewing among nine adult volunteers have been recorded as time series data with a three-dimensional motion capture system and the vertical components of the movements have been analyzed. To focus on occlusal phase of mastication, the following parameters have been examined: time lag of the head movements at the beginning of occlusal phase, perpendicular velocity of the head at the beginning of the phase of occlusion, and average velocity of the head during occlusal phase. The results showed that the head moved downward in mastication and the velocity of the head movements increased in the order of gum, gummi candies and kelp chewing. There is a possibility that the elasticity of a food bolus affects the activity of head movements, and the kinetic energy was increased to achieve effective destruction of a food bolus.

  17. Conditions of microvessel occlusion for blood coagulation in flow.

    PubMed

    Bouchnita, A; Galochkina, T; Kurbatova, P; Nony, P; Volpert, V

    2016-11-10

    Vessel occlusion is a perturbation of blood flow inside a blood vessel because of the fibrin clot formation. As a result, blood circulation in the vessel can be slowed down or even stopped. This can provoke the risk of cardiovascular events. In order to explore this phenomenon, we used a previously developed mathematical model of blood clotting to describe the concentrations of blood factors with a reaction-diffusion system of equations. The Navier-Stokes equations were used to model blood flow, and we treated the clot as a porous medium. We identify the conditions of partial or complete occlusion in a small vessel depending on various physical and physiological parameters. In particular, we were interested in the conditions on blood flow and diameter of the wounded area. The existence of a critical flow velocity separating the regimes of partial and complete occlusion was demonstrated through the mathematical investigation of a simplified model of thrombin wave propagation in Poiseuille flow. We observed different regimes of vessel occlusion depending on the model parameters both for the numerical simulations and in the theoretical study. Then, we compared the rate of clot growth in flow obtained in the simulations with experimental data. Both of them showed the existence of different regimes of clot growth depending on the velocity of blood flow.

  18. 21 CFR 880.5950 - Umbilical occlusion device.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Umbilical occlusion device. 880.5950 Section 880.5950 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED..., tie, tape, or other article used to close the blood vessels in the umbilical cord of a newborn...

  19. 21 CFR 880.5950 - Umbilical occlusion device.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Umbilical occlusion device. 880.5950 Section 880.5950 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL HOSPITAL AND PERSONAL USE DEVICES General Hospital and Personal Use...

  20. Hidden in Plain Sight: Occlusion in Pedagogical Genres

    ERIC Educational Resources Information Center

    Neaderhiser, Stephen E.

    2016-01-01

    Occluded genres in academia work "behind the scenes" to support and develop an academic's professional identity. However, while significant attention has been paid to occluded genres that support an academic's identity as a researcher, very little scholarship examines how occlusion operates in genres of pedagogy, such as the syllabus,…

  1. Inferior pancreaticoduodenal artery aneurysm associated with common hepatic artery occlusion.

    PubMed

    Bracale, G; Porcellini, M; Bernardo, B; Selvetella, L; Renda, A

    1996-12-01

    A unique case of true inferior pancreaticoduodenal artery aneurysm (IPDA) associated with occlusion of common hepatic artery is reported. Radiological and MRI findings are described. Because of high risk of visceral ischemia that contraindicated a percutaneous transluminal embolization, a successful tangential resection of aneurysm was performed.

  2. Radiation Safety During Interventions of Coronary Chronic Total Occlusion

    PubMed Central

    Tran, Phillip; Phan, Hung; R Shah, Sara; Latif, Faisal; Nguyen, Thach

    2015-01-01

    During percutaneous coronary interventions (PCI) for chronic total occlusion (CTO), prolonged procedures increase the risk of excessive radiation exposure. These situations harbor a major concern to protect patients and personnel in the cardiac interventional laboratory (CCL). Important questions regarding radiation safety for interventional cardiologists performing PCI for CTO lesions are discussed and concrete applications are suggested.

  3. Sex Differences during Visual Scanning of Occlusion Events in Infants

    ERIC Educational Resources Information Center

    Wilcox, Teresa; Alexander, Gerianne M.; Wheeler, Lesley; Norvell, Jennifer M.

    2012-01-01

    A growing number of sex differences in infancy have been reported. One task on which they have been observed reliably is the event-mapping task. In event mapping, infants view an occlusion event involving 1 or 2 objects, the occluder is removed, and then infants see 1 object. Typically, boys are more likely than girls to detect an inconsistency…

  4. Association between near occlusal contact areas and mixing ability.

    PubMed

    Horie, T; Kanazawa, M; Komagamine, Y; Hama, Y; Minakuchi, S

    2014-11-01

    This study investigated the relationship between occlusal contact and near contact areas defined by clenching intensity using electromyograms (EMGs) and mixing ability assessed with colour-changeable chewing gum. Participants comprised 44 dentate adults (24 men, 20 women) with a mean age of 28·2 ± 6·8 years. Silicone material was used to measure the occlusal contact and near contact areas (the area of each type of tooth, the total area of the first molar and second molar, the second premolar to the second molar and the first premolar to the second molar) defined by clenching intensity at 10% maximum voluntary contraction (MVC). Colour-changeable chewing gum was used to assess mixing ability. A colorimeter was used to measure colour changes, and the calculated colour difference (ΔE) was used as a measure of mixing ability. Correlation analysis of ΔE and occlusal contact and near contact areas revealed a significant positive correlation of 0·47 at 0-160 μm thicknesses of the silicone registration material of the second molar (P < 0·01). The near contact area with a thickness up to 200 μm was correlated with mixing ability, with the correlation strengthening as the interocclusal distance increased up to 160 μm. Notably, occlusal contact and near contact areas of the second molar were strongly correlated with mixing ability in dentate adults.

  5. Relationships between a clinical-visual scoring system and two histological techniques: a laboratory study on occlusal and approximal carious lesions.

    PubMed

    Kidd, E A M; Banerjee, A; Ferrier, S; Longbottom, C; Nugent, Z

    2003-01-01

    One aim of the present laboratory study was to determine whether a visual scoring system (ERK) developed for occlusal caries could be applied to approximal lesions. A new histological technique (autofluorescence, AF) recognises dentine that is soft and would be removed with an excavator during operative treatment. A second aim was to investigate the relationship between the visual scoring system (ERK) and AF of dentine both occlusally and approximally. The sample comprised 93 extracted teeth chosen to represent the range of visual scores on approximal and occlusal surfaces. After sectioning through the investigation site, the cut faces were examined in a stereomicroscope and the depth of demineralization was scored. Autofluorescence was viewed with a confocal laser scanning microscope. Results showed reasonable correlation between the visual scores and the stereomicroscope histological evaluations for occlusal surfaces and non-cavitated approximal surfaces. However, cavitated approximal surface lesions were less advanced histologically than cavitated occlusal carious lesions. The AF technique indicated that several lesions with intact surfaces would have had soft, excavatable dentine, whereas several with microcavities would not.

  6. Consequences of retinal image clarity versus occlusion (absent) versus diffusion.

    PubMed Central

    Jampolsky, A

    1994-01-01

    A series of clinical questions and stated hypotheses suggested in the pre-1960s regarding the differences between stimuli of occlusion and diffusion are presented (Part I) and are answered and confirmed by a series of experiments and data in animals and humans. A diffusion stimulus is extremely destructive to development of the acuity system in an eye per se (as well as producing myopia), and a unilateral diffusion stimulus is also destructive to development of the binocular system. Real occlusion is a no-stimulus condition that can be used to preserve normal acuity and binocular development, and as a delay tactic to successfully counteract the detrimental effect of diffusion. Binocular input differences (especially if one is a diffusion stimulus) are a major cause of strabismus in both the immature and mature binocular systems. The hypothesis was proposed that preoperative full-time alternate occlusion in infantile esotropia enhanced the binocularity outcome (for which supportive experimental data in animals and humans from our laboratories are discussed in Part III). Animal experiments during the 1960s and 1970s are reviewed relative to the confusion and conflict generated (Part II), since many of these experiments were based on the false assumptions that the unilateral eyelid closure model was a no-stimulus condition (because of the small amount of light transmitted). In fact, it was a worst-case severe stimulus with both monocular and binocular detrimental consequences. And the unilateral eyelid closure model usually produced either undetected or ignored strabismus in the animal experiments, with such strabismus severely compounding the detrimental effects of the eyelid closure model. Further confusion was added by the amblyopia therapeutic model in animals of "reverse eyelid occlusion" (which was really reverse diffusion) and which the author maintains was a gross distortion of the clinician's real occlusive patch over the better eye in the therapy of

  7. [Value and significance of therapy of cutting-in in occlusally loaded incisors].

    PubMed

    Ibrahim, O; Sponholz, H

    1989-10-01

    With the aid of the measurements of tooth mobility the treatment success of grinding was evaluated in 208 upper incisors of 54 patients, and the results were set into correlation with different factors. The results show that decreased tooth mobility following grinding was observed both in healthy periodontium and in diseased periodontium.

  8. Detection of Unexpected High Correlations between Balance Calibration Loads and Load Residuals

    NASA Technical Reports Server (NTRS)

    Ulbrich, N.; Volden, T.

    2014-01-01

    An algorithm was developed for the assessment of strain-gage balance calibration data that makes it possible to systematically investigate potential sources of unexpected high correlations between calibration load residuals and applied calibration loads. The algorithm investigates correlations on a load series by load series basis. The linear correlation coefficient is used to quantify the correlations. It is computed for all possible pairs of calibration load residuals and applied calibration loads that can be constructed for the given balance calibration data set. An unexpected high correlation between a load residual and a load is detected if three conditions are met: (i) the absolute value of the correlation coefficient of a residual/load pair exceeds 0.95; (ii) the maximum of the absolute values of the residuals of a load series exceeds 0.25 % of the load capacity; (iii) the load component of the load series is intentionally applied. Data from a baseline calibration of a six-component force balance is used to illustrate the application of the detection algorithm to a real-world data set. This analysis also showed that the detection algorithm can identify load alignment errors as long as repeat load series are contained in the balance calibration data set that do not suffer from load alignment problems.

  9. LOADED WAVEGUIDES

    DOEpatents

    Mullett, L.B.; Loach, B.G.; Adams, G.L.

    1958-06-24

    >Loaded waveguides are described for the propagation of electromagnetic waves with reduced phase velocities. A rectangular waveguide is dimensioned so as to cut-off the simple H/sub 01/ mode at the operating frequency. The waveguide is capacitance loaded, so as to reduce the phase velocity of the transmitted wave, by connecting an electrical conductor between directly opposite points in the major median plane on the narrower pair of waveguide walls. This conductor may take a corrugated shape or be an aperature member, the important factor being that the electrical length of the conductor is greater than one-half wavelength at the operating frequency. Prepared for the Second U.N. International ConferThe importance of nuclear standards is duscussed. A brief review of the international callaboration in this field is given. The proposal is made to let the International Organization for Standardization (ISO) coordinate the efforts from other groups. (W.D.M.)

  10. Differentiation between Good and Low-Responders to Intravitreal Ranibizumab for Macular Edema Secondary to Retinal Vein Occlusion

    PubMed Central

    Ebneter, Andreas; Zinkernagel, Martin S.; Wolf, Sebastian

    2016-01-01

    Background. Ranibizumab is approved for treatment of macular edema in eyes with retinal vein occlusion (RVO). Some eyes show low-response to treatment with regard to visual acuity gain (VA) and OCT central retinal thickness (CRT) reduction. The goal of this study was to quantify the percentage of low-responders. Methods. Treatment of naïve eyes with macular edema secondary to RVO was included and monthly VA and CRT were analyzed. Four weeks after the loading phase, and at the end of the study, eyes were grouped into low- and good responders based on predefined criteria. The responder and low-responder groups were then compared at various time points. Results. Forty-three eyes were included. Regarding VA, 27.9% were low-responders after the loading phase and 30.2% at the end of the study. For CRT, 34.9% were low-responders after the loading phase versus 27.9% at the end of the study. 75% of patients that were VA low-responders and 73.3% of CRT low-responders after loading phase remained low-responders at the end of the study. Conclusion. Approximately 30% of patients showed low response to ranibizumab after the loading phase and after 1 year of treatment. Two-thirds of patients that were low-responders after the loading phase remained low-responders after 1 year. PMID:28044102

  11. Genome sequence of an Adoxophyes orana granulovirus (AdorGV) occlusion body morphology mutant

    Technology Transfer Automated Retrieval System (TEKTRAN)

    - Genome sequence of an Adoxophyes orana granulovirus (AdorGV) occlusion body morphology mutant Baculoviruses package virus particles in a crystalline matrix of viral protein to form occlusion bodies. Occlusion bodies are used in biological control because the crystalline matrix protects the viral ...

  12. Evaluation of the occlusal contact of crowns fabricated with the bite impression method.

    PubMed

    Makino, Sachi; Okada, Daizo; Shin, Chiharu; Ogura, Reiko; Ikeda, Masaomi; Miura, Hiroyuki

    2013-09-30

    In prosthodontic treatment, reconstruction of a proper occlusal contact relationship is very important as well as reconstruction of a proper interproximal relationship and marginal fitness. Unfortunately, occlusal relationships are sometimes lost in the process of occlusal adjustment of crowns. The purpose of this study was to compare the occlusal contacts of single crown fabricated by two different types of impression techniques. Nine subjects, whose molars required treatment with crown restoration, were enrolled in this study. Full cast crowns were fabricated using two types of impression techniques: the conventional impression method (CIM) and the bite impression method (BIM). The occlusal contacts of crowns were precisely evaluated at the following stages: after occlusal adjustment on the articulator (Step 0), before occlusal adjustment in the mouth (Step 1), after occlusal adjustment at the intercuspal position (Step 2), and after occlusal adjustment during lateral and protrusive excursions (Step 3). The number of occlusal contacts of the crowns on the functional cusps fabricated with BIM was significantly greater than that with CIM after occlusal adjustment. For this reason, the crowns fabricated with BIM might have a more functionally desirable occlusal surface compared to the crowns fabricated with CIM.

  13. Balloon Occlusion of the Contralateral Iliac Artery to Assist Recanalization of the Ipsilateral Iliac Artery in Total Aortoiliac Occlusion: A Technical Note

    PubMed Central

    Jaffan, Abdel Aziz A.

    2013-01-01

    Endovascular recanalization of chronic total aortoiliac occlusion is technically challenging. Inability to reenter the true aortic lumen, following retrograde iliac recanalization, is one of the most common causes of failure. We describe a case of a total aortoiliac occlusion where balloon occlusion of the right common iliac artery, following its recanalization from a brachial approach, was used to facilitate antegrade recanalization of the occluded contralateral left common iliac artery. PMID:23762730

  14. Outcome and Treatment Effects in Stroke Associated with Acute Cervical ICA Occlusion

    PubMed Central

    Gliem, Michael; Lee, John-Ih; Barckhan, Aurica; Turowski, Bernd; Hartung, Hans-Peter; Jander, Sebastian

    2017-01-01

    Background Endovascular therapy (EVT) with stent retrievers in addition to i.v. thrombolysis (IVT) has proven effective in acute stroke patients with middle cerebral artery (MCA, M1 segment) and distal internal carotid artery (ICA) occlusion. Limited data exist concerning acute cervical ICA occlusion, either alone or in combination with intracranial ICA occlusion (tandem occlusion). Therefore we analyzed outcome and treatment effects in stroke associated with cervical ICA occlusion, with specific focus on the impact of intracranial ICA or M1 patency. Methods Seventy-eight patients with cervical ICA occlusion from our local stroke unit registry were analyzed retrospectively. Thrombolysis in Cerebral Infarction (TICI) classification, infarct size, modified Rankin scale (mRS), symptomatic intracerebral hemorrhage (ICH), and death were assessed as outcome parameters. Results Forty-three patients had isolated cervical ICA occlusion whereas 35 patients presented with extra-/intracranial tandem occlusion. Patients underwent IVT alone (n = 23), combined IVT/EVT (n = 28) or no treatment (n = 27). Treated and untreated patients with tandem occlusion had a worse outcome after 90 days compared to isolated cervical occlusion (OR for moderate outcome 0.29, 0.27–0.88, p = 0.01). Additional EVT improved outcome in patients with tandem occlusion (OR for moderate outcome: 15.43, 1.60–148.90, p = 0.008) but not isolated cervical occlusion (OR 1.33, 0.38–11.60, NS). Conclusions In contrast to tandem occlusion, stroke outcome in patients with isolated cervical ICA occlusion was generally more benign and not improved by combined IVT/EVT compared to IVT alone. Intracranial vessel patency may be critical for treatment decision in acute cervical ICA occlusion. PMID:28081270

  15. Bruxism in children and transverse plane of occlusion: Is there a relationship or not?

    PubMed Central

    Nahás-Scocate, Ana Carla Raphaelli; Coelho, Fernando Vusberg; de Almeida, Viviane Chaves

    2014-01-01

    OBJECTIVE: To assess the occurrence of bruxism in deciduous dentition and a potential association between the habit and the presence or absence of posterior crossbite. METHODS: A total of 940 patient files were assessed. They were gathered from the archives of University of São Paulo City - UNICID; however, 67 patient files were dismissed for not meeting the inclusion criteria. Therefore, 873 children, males and females, comprised the study sample. They were aged between 2-6 years old and came from six different public primary schools from the east of the city of São Paulo. Data were collected through questionnaires answered by parents/guardians and by clinical examinations carried out in the school environment in order to obtain the occlusal characteristics in the transverse direction. First, a descriptive statistical analysis of all variables was performed (age, sex, race, posterior crossbite, bruxism, headache and restless sleep); then, the samples were tested by means of chi-square test with significance level set at 0.05%. A logistic regression model was applied to identify the presence of bruxism. RESULTS: The prevalence of this parafunctional habit was of 28.8%, with 84.5% of patients showing no posterior crossbite. Regarding the association of bruxism with crossbite, significant results were not found. Children with restless sleep have 2.1 times more chances of developing bruxism, whereas children with headache have 1.5 more chances. CONCLUSION: Transverse plane of occlusion was not associated with the habit of bruxism. PMID:25715718

  16. Veno-occlusive disease of the liver after hemopoietic cell transplantation.

    PubMed

    Carreras, E

    2000-05-01

    The clinical syndrome of veno-occlusive disease (VOD) after hemopoietic cell transplantation is characterised by jaundice, painful liver enlargement, and fluid retention with weight gain. Cytoreductive therapy is presumably the primary cause of VOD, but several other agents (and a special susceptibility of the liver) can also play a role in its genesis. The risk of VOD can be predicted before BMT by analysing the presence or absence of the main risk factors. For the diagnosis of VOD most teams worldwide apply the clinical criteria developed by both the Seattle and Baltimore teams. Transjugular liver studies and some biological markers can help establish a correct differential diagnosis. In most cases clinical manifestations improve after several days, but 20-25% of patients could die of VOD. Data regarding whether or not pharmacological prophylactic measures are effective are contradictory. There a few therapeutical approaches directed towards the improvement of venular occlusion; recombinant tissue plasminogen activator and defibrotide can solve some cases of severe VOD.

  17. Automatically detect and track multiple fish swimming in shallow water with frequent occlusion.

    PubMed

    Qian, Zhi-Ming; Cheng, Xi En; Chen, Yan Qiu

    2014-01-01

    Due to its universality, swarm behavior in nature attracts much attention of scientists from many fields. Fish schools are examples of biological communities that demonstrate swarm behavior. The detection and tracking of fish in a school are of important significance for the quantitative research on swarm behavior. However, different from other biological communities, there are three problems in the detection and tracking of fish school, that is, variable appearances, complex motion and frequent occlusion. To solve these problems, we propose an effective method of fish detection and tracking. In this method, first, the fish head region is positioned through extremum detection and ellipse fitting; second, The Kalman filtering and feature matching are used to track the target in complex motion; finally, according to the feature information obtained by the detection and tracking, the tracking problems caused by frequent occlusion are processed through trajectory linking. We apply this method to track swimming fish school of different densities. The experimental results show that the proposed method is both accurate and reliable.

  18. Treatment Strategies for Acute Ischemic Stroke Caused by Carotid Artery Occlusion

    PubMed Central

    Li, Wei; Yin, Qin; Xu, Gelin; Liu, Xinfeng

    2016-01-01

    Background: Acute ischemic stroke caused by internal carotid artery (ICA) occlusion usually has a poor prognosis, especially the T occlusion cases without functional collaterals. The efficacy of intravenous (IV) or intra-arterial (IA) thrombolysis with recombinant tissue plasminogen activator (rt-PA) remains ambiguous in these patients. Eendovascular recanalization of the occluded carotid has been attempted in recent years as a potential strategy. However, the different etiologies of ICA occlusion pose a significant challenge to neurointerventionists. Recently, several endovascular evolvements have been reported in treating carotid occlusion-related stroke. This review summarizes the current status of treatment for acute ICA occlusion. PMID:27781043

  19. The effects of hard and soft occlusal splints on nocturnal bruxism.

    PubMed

    Okeson, J P

    1987-06-01

    Occlusal splints are commonly used for the treatment of nocturnal bruxism. This study investigated the effects of hard and soft occlusal splints on nighttime muscle activity. The nocturnal muscle activity of ten participants was recorded while wearing a hard and then a soft occlusal splint. The hard occlusal splint significantly reduced muscle activity in eight of the ten participants. The soft occlusal splint significantly reduced muscle activity in only one participant while causing a statistically significant increase in muscle activity in five of the ten participants.

  20. 14 CFR 23.509 - Towing loads.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    .... In addition: (1) A vertical load factor equal to 1.0 must be considered acting at the center of... main gear must be reacted as follows: (i) A reaction with a maximum value equal to the vertical reaction must be applied at the axle of the wheel to which the load is applied. Enough airplane inertia...

  1. 14 CFR 23.509 - Towing loads.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    .... In addition: (1) A vertical load factor equal to 1.0 must be considered acting at the center of... main gear must be reacted as follows: (i) A reaction with a maximum value equal to the vertical reaction must be applied at the axle of the wheel to which the load is applied. Enough airplane inertia...

  2. 14 CFR 23.509 - Towing loads.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    .... In addition: (1) A vertical load factor equal to 1.0 must be considered acting at the center of... main gear must be reacted as follows: (i) A reaction with a maximum value equal to the vertical reaction must be applied at the axle of the wheel to which the load is applied. Enough airplane inertia...

  3. 14 CFR 23.509 - Towing loads.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    .... In addition: (1) A vertical load factor equal to 1.0 must be considered acting at the center of... main gear must be reacted as follows: (i) A reaction with a maximum value equal to the vertical reaction must be applied at the axle of the wheel to which the load is applied. Enough airplane inertia...

  4. 14 CFR 23.509 - Towing loads.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    .... In addition: (1) A vertical load factor equal to 1.0 must be considered acting at the center of... main gear must be reacted as follows: (i) A reaction with a maximum value equal to the vertical reaction must be applied at the axle of the wheel to which the load is applied. Enough airplane inertia...

  5. On Critical Buckling Loads of Columns under End Load Dependent on Direction

    PubMed Central

    Başbük, Musa; Eryılmaz, Aytekin; Atay, M. Tarık

    2014-01-01

    Most of the phenomena of various fields of applied sciences are nonlinear problems. Recently, various types of analytical approximate solution techniques were introduced and successfully applied to the nonlinear differential equations. One of the aforementioned techniques is the Homotopy analysis method (HAM). In this study, we applied HAM to find critical buckling load of a column under end load dependent on direction. We obtained the critical buckling loads and compared them with the exact analytic solutions in the literature. PMID:27379303

  6. Secondary trauma from occlusion: three-dimensional analysis using the finite element method.

    PubMed

    Geramy, Allahyar; Faghihi, Sharieh

    2004-01-01

    Clinical effects of forces applied by dental occlusion on the periodontium have been evaluated for decades. Historically, trauma from occlusion has been considered as a major etiologic factor of inflammatory periodontal diseases, while some researchers have interpreted it to be of less importance or without any detectable importance in periodontics. In this study, five three-dimensional models of a maxillary central incisor were created using ANSYS 5.40. The only difference in each model was the height of the alveolar bone that showed from normal height (13 mm of alveolar bone height) to 8 mm of alveolar bone loss (5 mm of alveolar bone height). Five-point forces of 0.3 N summing up to 1.5 N were applied in a parallel line, 1 mm apical to the incisal edge on the palatal side in a palatolabial direction. The maximum (S1) and minimum (S3) principal stresses in the nodes of the labial side of the periodontal ligament (apical to the alveolar crest) were assessed. Analysis was done using the finite element method. An increase of S1 (up to 16 times in the cervical and 11.25 times in the apical area) and S3 (up to 17.13 times in the cervical and 9.9 times in the apical area) in comparison to the normal model was shown. The highest stress levels were traced in the subcervical area, except for the last model (8 mm of the alveolar bone loss). According to the results of this study, 2.5 mm of alveolar bone loss can be considered as a limit beyond which stress alterations were accelerated. Based on the FEM analysis, alveolar bone loss increases stress (S1 and S3) produced in the PDL, in spite of applying the same force vector.

  7. Lingualized integration: tooth molds and an occlusal scheme for edentulous implant patients.

    PubMed

    Lang, B R; Razzoog, M E

    1992-01-01

    The interface of bone and soft tissue to dental implants has been extensively documented, while the influence of biomechanics and the occlusal interface continues to be overlooked. Yet that same occlusal interface may ultimately be the prime factor in the lifetime survival rate of dental implants. What is lacking, for the practitioner, is a clear concept of the occlusal rehabilitation which is required and appropriate for the totally edentulous implant patient. Lingualized integration represents an occlusal scheme using specific tooth molds designed to improve the likelihood of maximum intercuspation and an absence of deflective occlusal contacts, provide cusp height for selective occlusal reshaping, and achieve a natural and pleasing appearance. Factors in the articulation and arrangement of the posterior teeth to assure the attainment of the fundamental goals of comfort, function, and appearance in occlusal rehabilitation for edentulous implant patients are included.

  8. Ultrastructural features of masseter muscle exhibiting altered occlusal relationship - a study in a rodent model

    SciTech Connect

    Lisboa, Marcio V.; Aciole, Gilberth T. S.; Oliveira, Susana C. P. S.; Marques, Aparecida M. C.; Pinheiro, Antonio L. B.; Santos, Jean N.; Baptista, Abrahao F.; Aguiar, Marcio C.

    2010-05-31

    The role of occlusion on Tempormandibular Disorders (TMD) is still unclear, mainly regarding muscular function. The aim of this study was to evaluate the occlusion highlights on masseter ultra morphology. Twenty Wistar rats were randomly divided in four groups: 10 for control group, 10 for occlusal alteration group (CCO). Rats underwent unilateral amputation of the left inferior and superior molar cusps to simulate an occlusal wear situation. The rats of control group had no occlusal wear. Half of the animals of each group was sacrificed in 14 days after the occlusal consuming and half 30 days after the occlusal consuming. The masseter muscles ipsilateral to the amputated molars were excised and processed for light microscopy, electron microscopy. The light microscopy did not show differences between the groups. The electron microscopy was able to detect a degree of intracellular damage in muscle fibers of CCO group: swollen mitochondria with disrupted cristae and cleared matrix, signs of hypercontraction of I bands and myofibril disorganization.

  9. Ultrastructural features of masseter muscle exhibiting altered occlusal relationship—a study in a rodent model

    NASA Astrophysics Data System (ADS)

    Lisboa, Marcio V.; Aciole, Gilberth T. S.; Oliveira, Susana C. P. S.; Marques, Aparecida M. C.; Baptista, Abrahão F.; Pinheiro, Antonio L. B.; Aguiar, Marcio C.; Santos, Jean N.

    2010-05-01

    The role of occlusion on Tempormandibular Disorders (TMD) is still unclear, mainly regarding muscular function. The aim of this study was to evaluate the occlusion highlights on masseter ultra morphology. Twenty Wistar rats were randomly divided in four groups: 10 for control group, 10 for occlusal alteration group (CCO). Rats underwent unilateral amputation of the left inferior and superior molar cusps to simulate an occlusal wear situation. The rats of control group had no occlusal wear. Half of the animals of each group was sacrificed in 14 days after the occlusal consuming and half 30 days after the occlusal consuming. The masseter muscles ipsilateral to the amputated molars were excised and processed for light microscopy, electron microscopy. The light microscopy did not show differences between the groups. The electron microscopy was able to detect a degree of intracellular damage in muscle fibers of CCO group: swollen mitochondria with disrupted cristae and cleared matrix, signs of hypercontraction of I bands and myofibril disorganization.

  10. Ocular vascular occlusive disorders: Natural history of visual outcome☆

    PubMed Central

    Hayreh, Sohan Singh

    2014-01-01

    Ocular vascular occlusive disorders collectively constitute the most common cause of visual disability. Before a disease can be managed, it is essential to understand its natural history, so as to be able to assess the likely effectiveness of any intervention. I investigated natural history of visual outcome in prospective studies of 386 eyes with non-arteritic anterior ischemic optic neuropathy (NA-AION), 16 eyes with non-arteritic posterior ischemic optic neuropathy, 697 eyes with central retinal vein occlusion (CRVO), 67 eyes with hemi-CRVO (HCRVO), 216 eyes with branch retinal vein occlusion (BRVO), 260 eyes with central retinal artery occlusion (CRAO), 151 eyes with branch retinal artery occlusion (BRAO) and 61 eyes with cilioretinal artery occlusion (CLRAO). My studies have shown that every one of these disorders consists of multiple distinct clinical sub-categories with different visual findings. When an ocular vascular occlusive disorder is caused by giant cell arteritis, which is an ophthalmic emergency, it would be unethical to do a natural history study of visual outcome in them, because in this case early diagnosis and immediate, intensive high-dose steroid therapy is essential to prevent any further visual loss, not only in the involved eye but also in the fellow, normal eye. In NA-AION in eyes seen ≤2 weeks after the onset, visual acuity (VA) improved in 41% of those with VA 20/70 or worse, and visual field (VF) improved in 26% of those with moderate to severe VF defect. In non-ischemic CRVO eyes with VA 20/70 or worse, VA improved in 47% and in ischemic CRVO in 23%; moderate to severe VF defect improved in 79% in non-ischemic CRVO and in 27% in ischemic CRVO. In HCRVO, overall findings demonstrated that initial VA and VF defect and the final visual outcome were different in non-ischemic from ischemic HCRVO – much better in the former than the latter. In major BRVO, in eyes with initial VA of 20/70 or worse, VA improved in 69%, and moderate to

  11. Endobronchial occlusive disease: Nd:YAG or PDT?

    NASA Astrophysics Data System (ADS)

    Regal, Anne-Marie; Takita, Hiroshi

    1991-06-01

    Patients with endobronchial occlusion commonly experience dyspnea, cough, hemoptysis, pneumonitis, and atelectasis. If luminal patency is not re-established, obstructive symptoms may progress to sepsis and death. Although the overall survival of patients with lung cancer may not be altered by relief of airway obstruction, the prognosis for this subset of patients may be improved by eliminating the septic complications of bronchial occlusion. Techniques to treat occluded bronchi include electro-fulguration, cryotherapy, brachytherapy, laser (CO2, Nd-YAG) therapy, and photodynamic therapy (PDT). These represent local forms of treatment and are intended to be palliative. Nd-YAG and PDT are the modalities more frequently utilized in this setting. Comparison of the two treatment forms may furnish insight regarding the appropriate role for each as individual therapies and as part of the armamentarium of cancer therapies.

  12. Endovascular treatment strategies for supra-aortic arterial occlusive disease.

    PubMed

    Peeters, P; Verbist, J; Deloose, K; Bosiers, M

    2005-06-01

    Because of the focal nature of stenoses or occlusions in the supra-aortic vasculature, the high blood-pressures in this area and the very low morbidity rates related to percutaneous therapy have largely replaced surgical revascularization as the initial treatment of choice for patients with supra-aortic arterial occlusive disease. The initial technical success and durability of percutaneous angioplasty (PTA) and stenting in these lesions is excellent. Nevertheless several factors can make PTA and stenting a complex procedure that requires advanced endovascular skills for a successful outcome. Profound knowledge of surgical reconstruction techniques or extra-anatomic bypasses remains mandatory, as it is occasionally required for failure of endovascular techniques or if contraindications exist.

  13. Crown angulation and inclination of Northern Thais with good occlusion.

    PubMed

    Jotikasthira, Dhirawat; Sheffield, Peter; Kalha, Anmol; Syed, Zameer

    2010-01-01

    When patients of differing ethnicities are treated with one bracket system, negative consequences for the occlusion can result. This study investigated the crown angulation and inclination on study casts of 60 Northern Thais (30 males and 30 females) with a good occlusion. In all study casts, each tooth (except the third molars) was evaluated with the orthodontic Torque Angulation Device (TAD) twice on the right side; this was also performed twice on the left side. The mean of the two evaluations was used for the statistical analysis. The means of the males and females were compared with the independent Student t test. The results were that the crown angulation of the mandibular first and second molars was significantly higher in females (P<.01) and that the crown inclination of all teeth did not differ between the two sexes.

  14. Effect of occlusion on joint sounds in asymptomatic individuals.

    PubMed

    Garcia, Alício Rosalino; Zuim, Paulo R Junqueira; Goiato, Marcelo Coelho; dos Santos, Paulo H; Ribeiro, Adriana Barbosa; Pita, Murillo Sucena; Flacón-Antenucci, Rosse M

    2008-01-01

    Occlusion is a predisposing factor for Temporomandibular Dysfunctions (TMD) of the joint, whose first sign and/or symptom is usually joint sound. To verify the effect of occlusion on joint sounds, temporomandibular joints (TMJ) were analyzed in 78 asymptomatic individuals with various dental conditions. Electrosonography was used to determine the intensity of the vibration in the temporomandibular joint (TMJ) on opening and closing the mouth. Transducers (piezoelectric accelerometer) were placed on the right and left joints. Results were tabled and analyzed using the Kruskal-Wallis test (a=0.05). It was concluded that TMJ vibration in partly edentulous individuals from Kennedy classes I, II and III is statistically higher than in dentate and fully edentulous subjects.

  15. An analog device to facilitate occlusion pressure measurements.

    PubMed

    Delavault, E; Saumon, G

    1980-06-01

    The "oclusion pressure" technique is widely used to test the response of respiratory centers to CO2. The graphic treatment of the test necessitates a fast recording of the mouth pressure signal, thus using a great deal of paper and requiring a tedious interpretation. The device described here controls an electromagnetic valve closing it during expiration and opening it after a given time delay, following the onset of inspiration. During that time only, the mouth pressure signal goes through an analog switch, the highest signal value is then equal to the occlusion pressure. This device allows the use of a slow recorder without loss of information. In addition, it has the advantage of generating very short respiratory occlusions, thus sparing the subject being tested from interferences in subsequent respiratory cycles. It can be used as a pretreatment unit to be associated with a microprocessor.

  16. Etiology and treatment of occlusal pathosis and associated facial pain.

    PubMed

    Okeson, J P

    1981-02-01

    The treatment of occlusal pathosis and associated facial pain is a difficult and complex problem. The interaction of two etiologic factors, occlusal interferences and psychologic stress, results in parafunctional activity. The most important prerequisite to selection of a treatment method is an understanding of the etiology of the problem. What dentistry needs is a mechanism by which the major etiologic factor of parafunctional activity can be identified for each patient. Treatment can then be directed toward the reduction or elimination of that factor. When treatment is directed toward the major cause of the problem, the likelihood of success will increase greatly. Continued research on this problem will yield new insights and means for the accurate determination of the etiology of parafunctional activity for each patient.

  17. Dental Occlusion among School Going Children of Maharashtra

    PubMed Central

    Kumar, Mukesh; Banerjee, Prasenjit; Gondhalekar, Rajesh; Gondhalekar, Rajeshri; Lall, Rajeev; Parwani, Rajkumar

    2014-01-01

    Background: A dental survey was conducted among the school going children of age group 6-13 yrs, focused to find out incidence of malocclusion so as to predict the probable time at which preventive measures can be taken. Materials and Methods: A survey was carried on 985 unrelated healthy subject, including of 575 boys and 410 girls and the population was divided into three economic group of upper, middle and lower class. Results: 1)In the study 57% of sample is found with normal occlusion.2)The proportion of malocclusion was higher in males.3)Lower income group sample showed highest proportion of malocclusion. Conclusion: In this study on school going children, it was found out that 57% of population showed normal occlusion and that malocclusion was higher in males and in lower income group population. PMID:25214733

  18. Popliteal artery occlusion in a young baseball athlete.

    PubMed

    Guo, Mindy Ming-Huey; Chuech, Leonard Shun-Jen; Yang, Cheng-Hsu; Wu, Chiung-Jen; Guo, Gary Bih-Fang

    2007-02-01

    Popliteal artery occlusion is a rare vascular complication in athletes and has not been previously documented in baseball players. A 21-year-old male baseball player presented with a 10-month history of progressive claudication because of repeated trauma-induced popliteal artery occlusion from frequently practicing stealing bases by sliding down onto his right leg. He was found to have a transient deficiency in both protein C and protein S. The patient underwent percutaneous transluminal recanalization angioplasty followed by anticoagulation therapy, with good results. This case illustrates the importance of awareness of this potential complication in baseball athletes, work-up for a hypercoagulable state and the feasibility of angioplasty therapy in the management of ischemic limbs after trauma.

  19. Cephalometric approach to the occlusal vertical dimension reestablishment.

    PubMed

    Zielak, João César; Gulin Neto, David; da Cunha, Leonardo Fernandes; Deliberador, Tatiana Miranda; Giovanini, Allan Fernando

    2014-01-01

    The occlusal vertical dimension (OVD) refers to the length of the face as determined by the amount of separation of the jaws. Its determination is important for the manufacture of restorations. However, defining the correct occlusal vertical dimension for edentulous patients is one of the most important steps for function and esthetics rehabilitation. Cephalometry is a standardized method of assessing dental and facial proportions and their interrelation. Additionally, cephalometric analysis of the facial vertical dimension can establish an individual pattern for each patient. This analysis should become a permanent part of each patient's record. Hence, this study presented a case report with the use of cephalometry as an auxiliary tool in the rehabilitation of OVD. Clinical relevance showed that cephalometric analysis can be an accurate and convenient instrument to treatment planning and prognostic of oral rehabilitation. The reader should understand the clinical implications of using cephalometry as a tool in the rehabilitation of OVD.

  20. Bilateral Central Vein Occlusion in a Case of Diaphragmatic Eventration

    PubMed Central

    STER, Anda-Maria; STAN, Cristina; GHERVAN, Mihaela

    2014-01-01

    Central Retinal Vein Occlusion (CRVO) is a severe retinal pathology, which causes visual impairment usually after the age of 40. Mostly unilateral, less than 10% of cases are bilateral. Affected young adults (under the age of 40), usually exhibit a hidden, underlying systemic disease. Thorough testing has to be done in order to spot the pathogenic agent. We present the case of a 25 years old woman with bilateral CRVO caused by Diaphragmatic Eventration and Chronic Respiratory Failure. PMID:25705293

  1. Secondary syphilis presenting with aortitis and coronary ostial occlusion.

    PubMed

    Chadwick, John A; MacNab, Anita; Sarma, Jaydeep; Ray, Simon; Kadir, Isaac; Muldoon, Eavan G

    2016-03-01

    Aortitis is an established manifestation of tertiary syphilis. We report a rare case of aortitis with ostial occlusion and left ventricular failure in secondary syphilis. Her management required a true multidisciplinary approach from multiple specialities due to complications of concomitant psychosis and a history of anaphylaxis to penicillin. This case illustrates the complexities of diagnosing and managing a rare presentation of this increasingly prevalent infection.

  2. Digital subtraction angiography in pediatric cerebrovascular occlusive disease

    SciTech Connect

    Faerber, E.N.; Griska, L.A.B.; Swartz, J.D.; Capitanio, M.A.; Popky, G.L.

    1984-08-01

    While conventional angiography has been used to demonstrate cerebrovascular occlusive disease in the past, digital subtraction angiography (DSA) is capable of showing progressive vascular involvement with ease, simplicity, and extremely low morbidity, making it particularly well suited for children and outpatients either alone or coordinated with computed tomography. The authors discuss the usefulness and advantages of DSA as demonstrated in 7 infants and children with hemiplegia, 4 of whom had sickle-cell disease.

  3. Endovascular Therapeutic Approaches for Acute Superior Mesenteric Artery Occlusion

    SciTech Connect

    Acosta, S. Sonesson, B.; Resch, T.

    2009-09-15

    The purpose of this study was to characterize the outcome of attempted endovascular intervention in patients with acute embolic or thrombotic superior mesenteric artery (SMA) occlusion. The records of 21 patients during a 3-year period between 2005 and 2008 were retrieved from the in-hospital registry. The first group included 10 patients (6 women and 4 men; median age 78 years) with acute embolic occlusion of the SMA. The median duration of symptoms from symptom onset to angiography was 30 hours (range 6 to 120). Synchronous emboli (n = 12) occurred in 6 patients. Embolus aspiration was performed in 9 patients, and 7 of these had satisfactory results. Complementary local thrombolysis was successful in 2 of 3 patients. Residual emboli were present at completion angiography in all 7 patients who underwent successful aspiration embolectomy, and bowel resection was necessary in only 1 of these patients. One serious complication occurred because of a long SMA dissection. The in-hospital survival rate was 90% (9 of 10 patients). The second group included 11 patients (10 women and 1 man; median age 68 years) with atherosclerotic acute SMA occlusions. The median time of symptom duration before intervention was 97 hours (range 17 to 384). The brachial, femoral, and SMA routes were used in 6, 7, and 5 patients, respectively. SMA stenting was performed through an antegrade (n = 7) or retrograde (n = 3) approach. Bowel resection was necessary in 4 patients. No major complications occurred. The in-hospital survival rate was 82% (9 of 11 patients). Endovascular therapy of acute SMA occlusion provides a good alternative to open surgery.

  4. Micropatterned Endotracheal Tubes Reduce Secretion-Related Lumen Occlusion.

    PubMed

    Mann, Ethan E; Magin, Chelsea M; Mettetal, M Ryan; May, Rhea M; Henry, MiKayla M; DeLoid, Heather; Prater, Justin; Sullivan, Lauren; Thomas, John G; Twite, Mark D; Parker, Albert E; Brennan, Anthony B; Reddy, Shravanthi T

    2016-12-01

    Tracheal intubation disrupts physiological homeostasis of secretion production and clearance, resulting in secretion accumulation within endotracheal tubes (ETTs). Novel in vitro and in vivo models were developed to specifically recapitulate the clinical manifestations of ETT occlusion. The novel Sharklet™ micropatterned ETT was evaluated, using these models, for the ability to reduce the accumulation of both bacterial biofilm and airway mucus compared to a standard care ETT. Novel ETTs with micropattern on the inner and outer surfaces were placed adjacent to standard care ETTs in in vitro biofilm and airway patency (AP) models. The primary outcome for the biofilm model was to compare commercially-available ETTs (standard care and silver-coated) to micropatterned for quantity of biofilm accumulation. The AP model's primary outcome was to evaluate accumulation of artificial airway mucus. A 24-h ovine mechanical ventilation model evaluated the primary outcome of relative quantity of airway secretion accumulation in the ETTs tested. The secondary outcome was measuring the effect of secretion accumulation in the ETTs on airway resistance. Micropatterned ETTs significantly reduced biofilm by 71% (p = 0.016) compared to smooth ETTs. Moreover, micropatterned ETTs reduced lumen occlusion, in the AP model, as measured by cross-sectional area, in distal (85%, p = 0.005), middle (84%, p = 0.001) and proximal (81%, p = 0.002) sections compared to standard care ETTs. Micropatterned ETTs reduced the volume of secretion accumulation in a sheep model of occlusion by 61% (p < 0.001) after 24 h of mechanical ventilation. Importantly, micropatterned ETTs reduced the rise in ventilation peak inspiratory pressures over time by as much as 49% (p = 0.005) compared to standard care ETTs. Micropatterned ETTs, demonstrated here to reduce bacterial contamination and mucus occlusion, will have the capacity to limit complications occurring during mechanical ventilation and

  5. Cephalometric indicators of the vertical dimension of occlusion.

    PubMed

    Strajnić, Ljiljana; Stanisić-Sinobad, Darinka; Marković, Dubravka; Stojanović, Ljiljana

    2008-06-01

    The aim of this investigation was to establish precise indicators of the vertical dimension of occlusion (VDO) which could be used as objective parameters in prosthodontic treatment providing exact control of the reconstructed vertical dimension of occlusion, early detection of errors and correction of the vertical dimension of occlusion during complete denture manufacturing. A total of 60 lateral cephalometric radiographs of subjects with natural dentition and class I skeletal jaw relationship, of Serbian nationality from the region of Vojvodina, were included in the investigation. Thirty subjects were males, and thirty females, their age range was 20 to 29 years. Cephalometric analysis was performed by using "Dr. Ceph" computer software (FYI Technologies, GA, USA). By evaluation of the craniofacial complex in subjects with natural dentition, horizontal dentofacial developmental growth was established in the examined sample and it was based on the relationship between the posterior and anterior total facial height (S-Go:N-Me, female X=68.96%, male X=72.8%) and statistically significant differences were found between the sexes in almost all linear dimensions and in the relation between the posterior and the anterior total facial height. Highly significant differences (p<0.001) between the sexes were found in regard to anterior total facial height (N-Me, male X=120.75 mm, female X=112.72 mm) and the anterior lower facial height (ANS-Me, male X=67.87 mm, female X=61.50 mm) (p<0.05). The proportions of the upper and lower anterior facial heights (N-ANS:ANS-Me, male X=79.36%, female X=80.63%) were within normal values in both sexes. Facial harmony existed both in men and women. Cephalometric study of the subjects with complete natural dentition included in this study provided important and specific parameters for optimal reconstruction of vertical dimension of occlusion in the treatment of edentulous patients.

  6. Ultrasound strain elastography in assessment of cortical mechanical behavior in acute renal vein occlusion: in vivo animal model.

    PubMed

    Gao, Jing; He, Wen; Cheng, Ling-Gang; Li, Xiao-Ya; Zhang, Xiou-Ru; Juluru, Krishna; Al Khori, Noor; Coya, Adrienne; Min, Robert

    2015-01-01

    To assess the correlation of quantitative ultrasound strain parameters with the severity of cortical edema in renal vein occlusion, we prospectively performed ultrasound strain elastography on a canine acute renal vein occlusion model prior to and following 10, 20, and 40min of renal vein ligation. Strain and strain relaxation time representing the deformation and relaxation of the renal cortices and reference soft tissue were produced by the external compression with the ultrasound transducer and estimated using commercially available 2-D speckle tracking software. Cortical thickness was additionally measured. Repeated-measures analysis of variance was used to examine the difference in cortical thickness, strain ratio (mean cortical strain divided by mean reference tissue strain), and strain relaxation time ratio (cortical relaxation time divided by reference tissue relaxation time) prior to and after renal vein ligation. Pearson's correlation coefficient was applied to test the relationship between strain parameters and the time of the renal vein ligation. There was a strong positive correlation between the duration of renal vein ligation and strain (R(2)=0.97) and strain relaxation time (R(2)=0.98) ratios. Significant differences in strain and strain relaxation time ratios were found at all measured timepoints (all P≪.001). Cortical thickness, however, showed no significant difference between timepoints (P=.065). Our result suggest that strain and strain relaxation time ratios may be used as quantitative markers for the assessment of the renal cortical mechanical behavior in subclinical acute renal vein occlusion.

  7. Endovascular occlusion of intracranial aneurysms with electrically detachable coils: Correlation of aneurysm neck size and treatment results

    SciTech Connect

    Zubillaga, A.F.; Guglielmi, G.; Vinuela, F.; Duckwiler, G.R.

    1994-05-01

    To devise a method to measure aneurysm neck size on angiographic films, and to correlate the sizes obtained with the extent of endovascular aneurysm occlusion, performed with electrically detachable coils. The angiograms of 79 intracranial aneurysms treated by endovascular occlusion using electrically detachable coils were retrospectively analyzed. A method using the average reported caliber of the major intracranial vessels was applied to determine the aneurysm neck sizes on the diagnostic angiograms. The cases were divided into two groups according to neck size, 4 mm being the discriminative value for small and wide necks. The posttreatment angiogram of each case was analyzed to evaluate the degree of occlusion achieved by the technique. Necks were successfully measured in 95% of the aneurysms. Complete aneurysm thrombosis was observed in 85% of the small-necked aneurysms and in 15% of the wide-necked aneurysms. Accurate angiographic measurements of neck diameter can be obtained in most aneurysms. The size of an aneurysm neck correlates well with the results of the endovascular treatment. Small-necked aneurysms can be satisfactorily occluded with this technique. In wide-necked aneurysms this technique should be reserved for lesions having a high surgical risk. 10 refs., 1 fig., 1 tab.

  8. Means for load variation during echocardiographic assessment of the Frank-Starling relationship.

    PubMed

    Atkins, B Z; Silvestry, S C; Davis, J W; Kisslo, J A; Glower, D D

    1999-10-01

    Because minimally invasive methods of preload variation are not validated for load-insensitive indexes of cardiac performance, intravenous nitroglycerin (NTG), phenylephrine, and saline solution (VOL) boluses were used in blocked and intact autonomic states to alter load and were compared with vena caval occlusion in the assessment of preload recruitable stroke work relationships between stroke work and left ventricular end-diastolic volume in dogs. In both autonomic states NTG and VOL produced comparable linear relationships. NTG and saline solution were combined with noninvasive measurements of left ventricular pressure and volume to construct echocardiographic relationships between stroke work and left ventricular end-diastolic cross-sectional area; NTG produced linear relationships similar to vena caval occlusion. Therefore NTG and VOL reliably alter load in constructing preload recruitable stroke work relationships, and NTG may be used with noninvasive measurements to provide load-insensitive estimates of cardiac function in a minimally invasive manner.

  9. Applied Stratigraphy

    NASA Astrophysics Data System (ADS)

    Lucas, Spencer G.

    Stratigraphy is a cornerstone of the Earth sciences. The study of layered rocks, especially their age determination and correlation, which are integral parts of stratigraphy, are key to fields as diverse as geoarchaeology and tectonics. In the Anglophile history of geology, in the early 1800s, the untutored English surveyor William Smith was the first practical stratigrapher, constructing a geological map of England based on his own applied stratigraphy. Smith has, thus, been seen as the first “industrial stratigrapher,” and practical applications of stratigraphy have since been essential to most of the extractive industries from mining to petroleum. Indeed, gasoline is in your automobile because of a tremendous use of applied stratigraphy in oil exploration, especially during the latter half of the twentieth century. Applied stratigraphy, thus, is a subject of broad interest to Earth scientists.

  10. Occlusion-free Blood Flow Animation with Wall Thickness Visualization.

    PubMed

    Lawonn, Kai; Glaßer, Sylvia; Vilanova, Anna; Preim, Bernhard; Isenberg, Tobias

    2016-01-01

    We present the first visualization tool that combines pathlines from blood flow and wall thickness information. Our method uses illustrative techniques to provide occlusion-free visualization of the flow. We thus offer medical researchers an effective visual analysis tool for aneurysm treatment risk assessment. Such aneurysms bear a high risk of rupture and significant treatment-related risks. Therefore, to get a fully informed decision it is essential to both investigate the vessel morphology and the hemodynamic data. Ongoing research emphasizes the importance of analyzing the wall thickness in risk assessment. Our combination of blood flow visualization and wall thickness representation is a significant improvement for the exploration and analysis of aneurysms. As all presented information is spatially intertwined, occlusion problems occur. We solve these occlusion problems by dynamic cutaway surfaces. We combine this approach with a glyph-based blood flow representation and a visual mapping of wall thickness onto the vessel surface. We developed a GPU-based implementation of our visualizations which facilitates wall thickness analysis through real-time rendering and flexible interactive data exploration mechanisms. We designed our techniques in collaboration with domain experts, and we provide details about the evaluation of the technique and tool.

  11. Plenoptic depth map in the case of occlusions

    NASA Astrophysics Data System (ADS)

    Yu, Zhan; Yu, Jingyi; Lumsdaine, Andrew; Georgiev, Todor

    2013-03-01

    Recent realizations of hand-held plenoptic cameras have given rise to previously unexplored effects in photography. Designing a mobile phone plenoptic camera is becoming feasible with the significant increase of computing power of mobile devices and the introduction of System on a Chip. However, capturing high numbers of views is still impractical due to special requirements such as ultra-thin camera and low costs. In this paper, we analyze a mobile plenoptic camera solution with a small number of views. Such a camera can produce a refocusable high resolution final image if a depth map is generated for every pixel in the sparse set of views. With the captured multi-view images, the obstacle to recovering a high-resolution depth is occlusions. To robustly resolve these, we first analyze the behavior of pixels in such situations. We show that even under severe occlusion, one can still distinguish different depth layers based on statistics. We estimate the depth of each pixel by discretizing the space in the scene and conducting plane sweeping. Specifically, for each given depth, we gather all corresponding pixels from other views and model the in-focus pixels as a Gaussian distribution. We show how it is possible to distinguish occlusion pixels, and in-focus pixels in order to find the depths. Final depth maps are computed in real scenes captured by a mobile plenoptic camera.

  12. New approaches to total occlusions: the guiding light

    NASA Astrophysics Data System (ADS)

    Neet, John M.; Wong, P. H.; Bonnier, J. J. R. M.

    2003-06-01

    There have been many innovations and technological advancements in balloon angioplasty since its introduction in the late 1970"s, but percutaneous intervention on a totally occluded artery is still a challenge to the vascular interventionalist. Catheter-based intervention that avoids an invasive surgical procedure is a clear and desired advantage for the patient. A total occlusion challenges the interventionalist because the path of the artery can not be seen in the occluded vessel since the flow of the radiopaque contrast media is blocked. Optical coherence reflectometry techniques have been shown to be able to differentiate between artery wall and occlusive materials allowing the lumen of the blocked artery to be seen inside the occlusion. During this past year, a guide wire that uses OCR for forward-looking guidance has received FDA 510(k) clearance and future generation devices that add radio frequency ablation capabilities are in clinical trials. Clinical results show that these new tools are addressing this subset of patients with percutaneous interventions with safety and effectiveness.

  13. Near-IR imaging of occlusal dental decay

    NASA Astrophysics Data System (ADS)

    Buehler, Christopher M.; Fried, Daniel

    2005-03-01

    Dental enamel manifests high transparency in the near-IR. Previous work demonstrated that near-IR light at 1310-nm is ideally suited for the transillumination of interproximal dental caries (dental decay in between teeth) [1]. However, most new dental decay occurs in the pits and fissures of the occlusal (biting) surfaces of posterior teeth. These caries lesions cannot be detected by x-rays during the early stages of decay due to the overlapping topography of the crown of the tooth. In this study, a near-IR imaging system operating at 1310-nm was used to acquire occlusal images by launching the near-IR light into the buccal surface of the tooth just above the gingival margin (gum-line). The near-IR light diffuses through the highly scattering dentin providing uniform back illumination of the enamel of the crowns allowing imaging of the occlusal surfaces. The near-IR images show high contrast between sound and demineralized areas. Demineralization (decay) can be easily differentiated from stains and pigmentation. Moreover, the high transparency of the enamel enables imaging at greater depth for the detection of subsurface decay hidden under the enamel. These early images suggest that the near-IR offers significant advantages over conventional visual, tactile and radiographic caries detection methods.

  14. Stereo matching with Mumford-Shah regularization and occlusion handling.

    PubMed

    Ben-Ari, Rami; Sochen, Nir

    2010-11-01

    This paper addresses the problem of correspondence establishment in binocular stereo vision. We suggest a novel spatially continuous approach for stereo matching based on the variational framework. The proposed method suggests a unique regularization term based on Mumford-Shah functional for discontinuity preserving, combined with a new energy functional for occlusion handling. The evaluation process is based on concurrent minimization of two coupled energy functionals, one for domain segmentation (occluded versus visible) and the other for disparity evaluation. In addition to a dense disparity map, our method also provides an estimation for the half-occlusion domain and a discontinuity function allocating the disparity/depth boundaries. Two new constraints are introduced improving the revealed discontinuity map. The experimental tests include a wide range of real data sets from the Middlebury stereo database. The results demonstrate the capability of our method in calculating an accurate disparity function with sharp discontinuities and occlusion map recovery. Significant improvements are shown compared to a recently published variational stereo approach. A comparison on the Middlebury stereo benchmark with subpixel accuracies shows that our method is currently among the top-ranked stereo matching algorithms.

  15. Blur and the perception of depth at occlusions.

    PubMed

    Zannoli, Marina; Love, Gordon D; Narain, Rahul; Banks, Martin S

    2016-01-01

    The depth ordering of two surfaces, one occluding the other, can in principle be determined from the correlation between the occlusion border's blur and the blur of the two surfaces. If the border is blurred, the blurrier surface is nearer; if the border is sharp, the sharper surface is nearer. Previous research has found that observers do not use this informative cue. We reexamined this finding. Using a multiplane display, we confirmed the previous finding: Our observers did not accurately judge depth order when the blur was rendered and the stimulus presented on one plane. We then presented the same simulated scenes on multiple planes, each at a different focal distance, so the blur was created by the optics of the eye. Performance was now much better, which shows that depth order can be reliably determined from blur information but only when the optical effects are similar to those in natural viewing. We asked what the critical differences were in the single- and multiplane cases. We found that chromatic aberration provides useful information but accommodative microfluctuations do not. In addition, we examined how image formation is affected by occlusions and observed some interesting phenomena that allow the eye to see around and through occluding objects and may allow observers to estimate depth in da Vinci stereopsis, where one eye's view is blocked. Finally, we evaluated how accurately different rendering and displaying techniques reproduce the retinal images that occur in real occlusions. We discuss implications for computer graphics.

  16. Decoding figure-ground occlusions from contours and shading

    NASA Astrophysics Data System (ADS)

    Kim, Juno; Anstis, Stuart

    2016-07-01

    Visual experience of surface properties relies on accurately attributing encoded luminance variations (e.g., edges and contours) to any one of several potential environmental causes. We examined the role of differences in the local shading directions across sharp contours in (i) identifying occlusion boundaries and (ii) perceiving the depth layout of adjacent surfaces. We used graphical rendering to control the orientation of a simulated light source, and hence the shading direction between adjacent surface regions that met at a common edge. We call the difference in shading direction across the edge the delta shading angle. We found that delta-shaded edges looked like occluding boundaries. We also found that the perceived figure-ground organisation of the adjacent surface regions depended on an assumed lighting from above prior. Shaded regions experienced as convex surfaces illuminated from above were perceived as occluding surfaces in the foreground. We computed an image-based measure of delta shading using the difference in local shading direction (the orientation field) and found this model could reliably account for observer judgments of surface occlusion, better than local (in-)coherence in the orientation of isophotes across the edge alone. However, additional information from co-alignment of isophotes relative to the edge is necessary to explain figure-ground distinctions across a broad class of occlusion events. We conclude that both local and global measures of shading direction are needed to explain perceived scene organisation, and material appearance more generally.

  17. Channel cooperation for anti-occlusion visible light communication systems

    NASA Astrophysics Data System (ADS)

    Liu, Yuxin; Huang, Zhitong; Li, Wei; Ji, Yuefeng

    2016-10-01

    The need to exchange data wirelessly has increased as the growth of the number of mobile devices. Visible light communication (VLC) is a promising technology to alleviate the growing traffic problem. However, the occlusion problem is a difficulty in VLC system. In order to solve the problem, an anti-occlusion VLC system has been proposed in this article. In this VLC system, we propose the channel cooperative selection mechanism, which is based on the best-response dynamics and best response strategies of the game theory. This mechanism uses bit error ratio (BER) as the utility function to optimize system performance. In addition, the system provides three candidate communication channels, including direct channel, indirect channel, and mixed channel, to active users who will select the optimal communication channel. Moreover, the anti-occlusion VLC system has many application scenarios, such as the office, which has practical significance. For verifying the validity of the proposed mechanism, we accomplish the simulation results in terms of BER and throughput in different communication cases. It is demonstrated that the proposed channel cooperative selection mechanism in VLC systems offers superior performance in environment of obstructions.

  18. Accidental ingestion of an inter-occlusal device used for the restoration of occlusion: a case report.

    PubMed

    Vasconcellos, Walison Arthuso; Braga, Neilor Mateus Antunes; Moretzsohn, Luciana Dias; Lanza, Marcos Daniel Septimio; Lanza, Marcos Dias; Rocha, Wellington Márcio dos Santos

    2014-09-01

    The accidental swallowing of prosthetic devices has been discussed in the relevant literature as an unusual, although ordinary, event in clinical practice. This article aims at reporting the ingestion of an inter-occlusal device used to restore the Vertical Dimension of Occlusion (VDO) which, during the ingestion of an analgesic pill, was accidentally swallowed. The patient was sent to the Clinics Hospital UFMG where, upon taking radiographs, the device was located in the upper third of the esophagus. The device was removed during an endoscopic exam with the help of forceps for removing foreign objects. Dealing with a relevant situation, one may conclude that patients who use removable intra-oral devices must take part in a reevaluation protocol in order to detect adaptation and retention of these devices, as well as proper instruction for the patient.

  19. Applied oceanography

    SciTech Connect

    Bishop, J.M.

    1984-01-01

    This book combines oceanography principles and applications such as marine pollution, resources, and transportation. It is divided into two main parts treating the basic principles of physical oceanography, and presenting a unique systems framework showing how physical oceanography, marine ecology, economics, and government policy may be combined to define the newly developing field of applied oceanography.

  20. Applied Enzymology.

    ERIC Educational Resources Information Center

    Manoharan, Asha; Dreisbach, Joseph H.

    1988-01-01

    Describes some examples of chemical and industrial applications of enzymes. Includes a background, a discussion of structure and reactivity, enzymes as therapeutic agents, enzyme replacement, enzymes used in diagnosis, industrial applications of enzymes, and immobilizing enzymes. Concludes that applied enzymology is an important factor in…

  1. Near infrared image processing to quantitate and visualize oxygen saturation during vascular occlusion.

    PubMed

    Jalil, B; Salvetti, O; Potì, L; Hartwig, V; Marinelli, M; L'Abbate, A

    2016-04-01

    The assessment of microcirculation spatial heterogeneity on the hand skin is the main objective of this work. Near-infrared spectroscopy based 2D imaging is a non-invasive technique for the assessment of tissue oxygenation. The haemoglobin oxygen saturation images were acquired by a dedicated camera (Kent Imaging) during baseline, ischaemia (brachial artery cuff occlusion) and reperfusion. Acquired images underwent a preliminary restoration process aimed at removing degradations occurring during signal capturing. Then, wavelet transform based multiscale analysis was applied to identify edges by detecting local maxima and minima across successive scales. Segmentation of test areas during different conditions was obtained by thresholding-based region growing approach. The method identifies the differences in microcirculatory control of blood flow in different regions of the hand skin. The obtained results demonstrate the potential use of NIRS images for the clinical evaluation of skin disease and microcirculatory dysfunction.

  2. Overcoming shadowing and occlusion in imagery with error-resilient processing

    NASA Astrophysics Data System (ADS)

    Hsu, Charles; DuBosq, Todd W.; Moyer, Steven K.; Flug, Eric; Jenkins, Jeffrey; Landa, Joseph S.; Byrd, Kenneth; Szu, Harold

    2014-05-01

    Due to the delay of sequential 3-D Lidar image acquisition while an uncooperative human target is in motion, the image may generate missing or occlusion pixels. We wish to minimize the impact of image acquisition of a moving target for aided target recognition. We apply the standard Fourier transform algorithms for an error resilience restoration to minimize the impact to the Human Visual System (HVS) which tends to overly emphasize the edge and the artificially generated discontinuity in missing pixels. We compared (i) classical phase retrieval scheme: Gerchburg-Saxon-Hayes-Papoulis (GSHP) and (ii) the Compressive Sensing scheme: Candes-Romberg-Donohoe-Tao (CRDT). The following two lessons were learned: The mechanism is based on Gibbs overshooting of a step-discontinuity. It is based on relocating the sparsely sampled zeros at missing pixel locations a la spatial and spatial frequency inner product conformal mapping property.

  3. Mouse model of sustained elevation in intraocular pressure produced by episcleral vein occlusion.

    PubMed

    Ruiz-Ederra, Javier; Verkman, A S

    2006-05-01

    We have developed an inducible mouse model of glaucoma based on episcleral vein cauterization (EVC). Intraocular pressure (IOP) elevation in adult mice was produced by cauterizing three episcleral veins. Serial IOP measurements were done by induction-impact tonometry. IOP was significantly elevated by 104+/-20% in 20 out of 23 mice (87%) within the first day after EVC, and remained elevated for 4 weeks, with mean IOP 94% higher in EVC-treated vs. contralateral control eyes. Aqueous outflow blockade was verified from the IOP response to pulsed fluid infusions into the anterior chamber. Retinal ganglion cell (RGC) loss, determined by retrograde labelling using Fluoro-Gold applied to the superior colliculous, was approximately 20% at 2 weeks after EVC. We conclude that episcleral vein occlusion in mice produces significant and sustained elevation in IOP associated with increased outflow resistance and RGC loss, and thus may be useful to model glaucoma in genetically modified and drug-treated mice.

  4. Load cell having strain gauges of arbitrary location

    DOEpatents

    Spletzer, Barry

    2007-03-13

    A load cell utilizes a plurality of strain gauges mounted upon the load cell body such that there are six independent load-strain relations. Load is determined by applying the inverse of a load-strain sensitivity matrix to a measured strain vector. The sensitivity matrix is determined by performing a multivariate regression technique on a set of known loads correlated to the resulting strains. Temperature compensation is achieved by configuring the strain gauges as co-located orthogonal pairs.

  5. End Stage Renal Disease as a Potential Risk Factor for Retinal Vein Occlusion.

    PubMed

    Chen, San-Ni; Yang, Te-Cheng; Lin, Jian-Teng; Lian, Ie-Bin

    2015-11-01

    End stage renal disease (ESRD) has been reported to be an important risk factor for systemic vascular disease. Retinal vein occlusion (RVO) is closely related with cardiovascular diseases; however, its association with ESRD had not been reported. The aim of the study was to investigate whether ESRD is a risk factor for RVO, including central retinal vein occlusion (CRVO) and branch retinal vein occlusion (BRVO). This population-based study is based on the longitudinal data from Taiwan National Health Insurance Research Database. The study cohort comprised 5344 patients with diagnosis of ESRD on hemodialysis or peritoneal dialysis during the period from January 1996 to December 2011. For each ESRD patient, we selected 20 non-ESRD patients matched on age and sex. Each ESRD patient and his/her controls were followed from the initiation of renal dialysis until either the diagnosis of RVO or censorship. Kaplan-Meier method was used to compare the hazard of RVO between cohorts. Stratified Cox proportional hazard models were applied to estimate the hazard ratio (HR) adjusted by the comorbidities of RVO including diabetes mellitus (DM), hypertension, hypercholesteremia, and hypertriglyceridemia. After stratifying by DM status, the statistics were applied again to examine the associations among the DM cohort and non-DM cohort.The 16-year RVO cumulative incidence for ESRD cohort was 2-fold to the non-ESRD (1.01% vs 0.46%). After matching with age, sex, hypertension, and hypercholesteremia, the adjusted HR was 1.46 (95% confidence interval = 1.07-2.01, P value = 0.018). By further excluding patients with DM, the adjusted HR escalated to 2.43 (95% confidence interval = 1.54-3.83, P < 0.001). In contrast, there was no significant risk of ESRD on RVO in the DM patients (HR = 1.03). We conclude that among the non-DM patients, ESRD cases had significantly higher RVO rate than the non-ESRD, which indicates that ESRD maybe a potential risk factor for the development of RVO in

  6. High payload six-axis load sensor

    DOEpatents

    Jansen, John F.; Lind, Randall F.

    2003-01-01

    A repairable high-payload six-axis load sensor includes a table, a base, and at least three shear-pin load transducers removably mounted between the table and the base. Removable mounting permits easy replacement of damaged shear pins. Preferably, the shear-pin load transducers are responsive to shear forces imparted along the two axes perpendicular to an axis of minimum sensitivity characteristic of the transducer. Responsive to an applied shear force, each shear-pin load transducer can produce an electrical signal proportional to the reaction force. The load sensor can further include a structure for receiving the proportional electrical signals and computing the applied load corresponding to the proportional electrical signals. The computed load can be expressed in terms of a three-dimensional XYZ Cartesian coordinate system.

  7. Analysis of occlusal contacts in different types of prosthodontic appliances, Eichner classifications, presence RCP-ICP slide and the type of occlusion.

    PubMed

    Stipetić, J; Celebić, A; Baucić, I; Lazić, B; Komar, D; Bratolić, V; Catić, A; Stefancić, S

    2001-06-01

    The aim of the study was to determine the number and the type of the occlusal contacts (strong, weak) with respect to the type of the prosthodontic appliance (fixed, removable, combined fixed-removable) and with respect to the Eichner classification in patients with their appliances being in a good function for a long time. The aim of the study was also to determine the number and the type of the occlusal contacts (strong, weak) with respect to the type of occlusion (canine guided, group function or balanced) and the presence of the RCP-ICP slide. A total of 440 patients with different types of prosthodontic appliances were examined for the antagonistic occlusal contacts using occlusal strips of 11 microm and 50 microm. The average number of occlusal contacts was 10.5 for the upper and 10.46 for the lower posterior teeth, approximately 5 on each side of the tooth arch. The results of the study suggest that the biggest number of occlusal contacts were recorded for the small span fixed appliances (2 on average), the greater span fixed and fixed-removable prosthodontic appliances exhibited 1.6 occlusal contacts, and the removable complete denture exhibited 1.2 contact per the tooth in the posterior region. The number of the hard occlusal contacts was significantly greater in fixed and fixed-removable prosthodontic appliances in comparison with the complete dentures (p < 0.05), while there was no significant difference between the prosthodontic appliances for the weak occlusal contacts (p > 0.05). The overall number of the occlusal contacts, as well as the number of the hard occlusal contacts was significantly greater in the Eichner class I cases (p < 0.05) in comparison with the Eichner classes II and III. The number of the weak occlusal contacts showed no significant differences with respect to the Eichner classification (p > 0.05). There was no significant difference in the number of occlusal contacts between the appliances with RCP-ICP slide and where ICP and RCP

  8. Regulation of native collateral vessel dilation after coronary occlusion in the dog.

    PubMed

    Lamping, K G; Bloom, E N; Harrison, D G

    1994-02-01

    The purpose of this study was to examine mechanisms involved in the response of native collaterals to coronary occlusion. In anesthetized dogs native collaterals were identified as vessels coursing between the left anterior descending and left circumflex arteries using fluorescence angiography. After a left anterior descending occlusion in 12 dogs, collaterals < 100 microns in diameter progressively dilated by 21 +/- 4% (n = 12) 1 min after occlusion and by 39 +/- 6% 15 min after occlusion. Collaterals > 100 microns in diameter did not dilate after coronary occlusion. NG-nitro-L-arginine (1 mg/min intracoronary) caused constriction under basal conditions in collaterals < 100 microns but did not prevent the dilation of collaterals after occlusion. In contrast, glibenclamide (10(-5) M), an inhibitor of ATP-sensitive potassium channels, had no effect on baseline diameter of collaterals < 100 microns diameter but completely prevented dilation of collaterals after occlusion. We conclude that collaterals are not maximally dilated immediately after a coronary occlusion but rather progressively dilate for at least 15 min after an occlusion. This dilation of native collaterals after an occlusion is not mediated by release of an endothelium-derived relaxing factor derived from L-arginine but is mediated by activation of ATP-sensitive K+ channels.

  9. The difficult relationship between occlusal interferences and temporomandibular disorder - insights from animal and human experimental studies.

    PubMed

    Xie, Q; Li, X; Xu, X

    2013-04-01

    The aetiology of temporomandibular disorder (TMD) is multifactorial, and numerous studies have addressed that occlusion may be of great importance. However, whether occlusion plays a crucial role in the pathogenesis of TMD remains controversial. Study designs utilising animal models have been used to study the effects of artificial occlusal alterations. Experimental traumatic occlusion affects blood flow in the temporomandibular joint and results in changes in the condylar cartilage, and artificial occlusal interference induces masticatory muscle nociceptive responses that are associated with peripheral sensitisation and lead to central sensitisation, which maintains masticatory muscle hyperalgesia. The possibility that occlusal interference results in TMD has been investigated in humans using a double-blind randomised design. Subjects without a history of TMD show fairly good adaptation to interferences. In contrast, subjects with a history of TMD develop a significant increase in clinical signs and self-report stronger symptoms (occlusal discomfort and chewing difficulties) in response to interferences. Meanwhile, psychological factors appear meaningful for symptomatic responses to artificial interferences in subjects with a history of TMD. Thus, individual differences in vulnerability to occlusal interferences do exist. Although there are advantages and disadvantages to using human and animal occlusal interference models, these approaches are indispensable for discovering the role of occlusion in TMD pathogenesis.

  10. rt-PA Thrombolysis in Acute Thromboembolic Upper-Extremity Arterial Occlusion

    SciTech Connect

    Cejna, Manfred; Salomonowitz, Erich; Wohlschlager, Helmut; Zwrtek, Karin; Boeck, Rudolf; Zwrtek, Ronald

    2001-07-15

    Purpose: Retrospective analysis of the results of rt-PA thrombolysis in the treatment of acute thromboembolic occlusion of the upper limb.Methods: Of 55 patients with demonstrated acute embolic arterial occlusion, rt-PA thrombolysis was performed on 40 occlusions in 38 patients (23 women with a mean age of 62 years, range 32-85 years; 15 men with a mean age of 65 years, range 32-92 years) according to the following design: 6 mg rt-PA/hr for 30 min, 3 mg rt-PA/hr for the next 30 min, 1 mg rt-PA/hr for 7 hr, and 0.4 mg rt-PA/hr until the end of lysis. Onset of symptoms varied from 1 to 14 days. Included were three isolated upper-arm occlusions, nine combined brachial and forearm occlusions, and 28 forearm and hand artery occlusions.Results: The overall success rate was 55%. The lysis results for isolated upper arm, combined brachial and forearm occlusions, and forearm and hand artery occlusions were 100%, 66%, and 46%, respectively. In eight patients surgical embolectomy had to be performed after failed thrombolysis. No amputation was required in the follow-up period. No lethal complications occurred.Conclusions: Interventional rt-PA treatment of proximal upper-extremity arterial occlusions may be performed with comparable success rates to surgical embolectomy and without severe complications. For distal occlusions the results are inferior to the success rates obtained with surgery.

  11. Applied Nanotoxicology

    PubMed Central

    Hobson, David W.; Roberts, Stephen M.; Shvedova, Anna A.; Warheit, David B.; Hinkley, Georgia K.; Guy, Robin C.

    2016-01-01

    Nanomaterials, including nanoparticles and nanoobjects, are being incorporated into everyday products at an increasing rate. These products include consumer products of interest to toxicologists such as pharmaceuticals, cosmetics, food, food packaging, household products, and so on. The manufacturing of products containing or utilizing nanomaterials in their composition may also present potential toxicologic concerns in the workplace. The molecular complexity and composition of these nanomaterials are ever increasing, and the means and methods being applied to characterize and perform useful toxicologic assessments are rapidly advancing. This article includes presentations by experienced toxicologists in the nanotoxicology community who are focused on the applied aspect of the discipline toward supporting state of the art toxicologic assessments for food products and packaging, pharmaceuticals and medical devices, inhaled nanoparticle and gastrointestinal exposures, and addressing occupational safety and health issues and concerns. This symposium overview article summarizes 5 talks that were presented at the 35th Annual meeting of the American College of Toxicology on the subject of “Applied Nanotechnology.” PMID:26957538

  12. 14 CFR 29.511 - Ground load: unsymmetrical loads on multiple-wheel units.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... gear units, 60 percent of the total ground reaction for the gear unit must be applied to one wheel and... specified load for the gear unit must be applied to either wheel except that the vertical ground...

  13. 14 CFR 29.511 - Ground load: unsymmetrical loads on multiple-wheel units.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... gear units, 60 percent of the total ground reaction for the gear unit must be applied to one wheel and... specified load for the gear unit must be applied to either wheel except that the vertical ground...

  14. [The Bayesian framework of detection of cariesgenic Streptoccocus in dental plaque in children with distal occlusion under orthodontic treatment].

    PubMed

    Chesnokov, V A; Chesnokova, M G; Mironov, A Iu; Turchaninov, D V; Kriga, A S

    2013-08-01

    The application of Bayes theorem in medical diagnostic includes such important step as derivation for every symptom and diagnosis data values of finite or a posteriori probability of presence of germ, for instance S. sanguis, in patients receiving orthodontic treatment. This value expresses importance of the given symptoms for detection of germ presence. In the implemented studies the Bayes theorem was applied to evaluate probability of presence of particular germ in particular concentration (degree of semination, CO) under concrete symptom group. The rates were used to calculate probability of presence of cariesgenic streptococcus S. mutans and S. sanguis in prospect patient. The rates were calculated for the group with fixed orthodontic apparatuses. The high degree of risk of development of caries in children under orthodontic treatment is conditioned by a whole complex of existing unfavorable factors present in oral cavity. Hence, a powerful negative potential to develop expressed cariesgenic situation in oral cavity is present. The analysis of medical data of patients with distal occlusion was applied using Bayes theorem from the point of view their diagnostic value. The study established 36 symptoms, factors, risk factors and background diseases common in case of distal occlusion in children. The probability to detect the mentioned characteristics and likelihood ratio under different degree of concentration of cariesgenic Streptococcus mutans and Streptococcus sanguis in dental plaque of children was considered. The establishment of character of likelihood ratio for different qualitative content of streptococcus in case of isolation from biotope of dental plaque permitted to determine the informative characteristics. The Bayesian model can be applied in clinics as a computer program to process incoming information about patients with distal occlusion under active orthodontic treatment. The developed diagnostic algorithm in a fast and simple mode of clinical

  15. A novel dual-frequency loading system for studying mechanobiology of load-bearing tissue.

    PubMed

    Zhang, Chunqiu; Qiu, Lulu; Gao, Lilan; Guan, Yinjie; Xu, Qiang; Zhang, Xizheng; Chen, Qian

    2016-12-01

    In mechanobiological research, an appropriate loading system is an essential tool to mimic mechanical signals in a native environment. To achieve this goal, we have developed a novel loading system capable of applying dual-frequency loading including both a low-frequency high-amplitude loading and a high-frequency low-amplitude loading, according to the mechanical conditions experienced by bone and articular cartilage tissues. The low-frequency high-amplitude loading embodies the main force from muscular contractions and/or reaction forces while the high-frequency low-amplitude loading represents an assistant force from small muscles, ligaments and/or other tissue in order to maintain body posture during human activities. Therefore, such dual frequency loading system may reflect the natural characteristics of complex mechanical load on bone or articular cartilage than the single frequency loading often applied during current mechanobiological experiments. The dual-frequency loading system is validated by experimental tests using precision miniature plane-mirror interferometers. The dual-frequency loading results in significantly more solute transport in articular cartilage than that of the low-frequency high-amplitude loading regiment alone, as determined by quantitative fluorescence microscopy of tracer distribution in articular cartilage. Thus, the loading system can provide a new method to mimic mechanical environment in bone and cartilage, thereby revealing the in vivo mechanisms of mechanosensation, mechanotransduction and mass-transport, and improving mechanical conditioning of cartilage and/or bone constructs for tissue engineering.

  16. Crane-Load Contact Sensor

    NASA Technical Reports Server (NTRS)

    Youngquist, Robert; Mata, Carlos; Cox, Robert

    2005-01-01

    impedance between the pins and the load. The instrument includes a signal generator and voltage-measuring circuitry, and is connected to the load and the base as shown in Figure 2. The output of the signal generator (typically having amplitude of the order of a volt) is applied to the load via a 50-resistor, and the voltage between the load and the pins is measured. When the load and the pins are not in contact, the impedance between them is relatively high, causing the measured voltage to exceed a threshold value. When the load and the pins are in contact, the impedance between them falls to a much lower value, causing the voltage to fall below the threshold value. The voltage-measuring circuitry turns on a red light-emitting diode (LED) to indicate the lower-voltage/ contact condition. Whenever the contact has been broken and the non-contact/higher-voltage condition has lasted for more than 2 ms, the voltage-measuring circuitry indicates this condition by blinking a green LED.

  17. Acute Stroke and Obstruction of the Extracranial Carotid Artery Combined with Intracranial Tandem Occlusion: Results of Interventional Revascularization

    SciTech Connect

    Lescher, Stephanie Czeppan, Katja; Porto, Luciana; Singer, Oliver C.; Berkefeld, Joachim

    2015-04-15

    PurposeDue to high thrombus load, acute stroke patients with tandem obstructions of the extra- and intracranial carotid arteries or the middle cerebral artery show a very limited response to systemic thrombolysis. Interventional treatment with mechanical thrombectomy—often in combination with acute stenting of underlying atherosclerotic stenosis or dissection—is increasingly used. It has been shown that such complex interventions are technically feasible. The lack of optimal management strategies and clinical data encouraged us to review our acute stroke interventions in patient with anterior circulation tandem lesions to determine lesion patterns, interventional approaches, and angiographic or clinical outcomes.Patients and MethodsWe retrospectively analyzed a series of 39 consecutive patients with intracranial vessel occlusion of the anterior circulation simultaneously presenting with high-grade cervical internal carotid artery (ICA) stenosis or occlusion.ResultsEmergency ICA stent implantation was technically feasible in all patients, and intracranial recanalization with TICI ≥ 2b was reached in a large number of patients (64 %). Good clinical outcomes (mRS ≤ 2 at 3 months) were achieved in one third of the patients (36 %). Symptomatic hemorrhages occurred in four patients (10 %). Mortality was 10 %.ConclusionEndovascular recanalization of acute cervical carotid artery occlusion was technically feasible in all patients, and resulted in high extra- and intracranial revascularization rates. A trend for favorable clinical outcome was seen in a higher TICI score, younger age, good collateral status, and combined IV rTPA and endovascular therapy.

  18. Buffet Load Alleviation

    NASA Technical Reports Server (NTRS)

    Ryall, T. G.; Moses, R. W.; Hopkins, M. A.; Henderson, D.; Zimcik, D. G.; Nitzsche, F.

    2004-01-01

    High performance aircraft are, by their very nature, often required to undergo maneuvers involving high angles of attack. Under these conditions unsteady vortices emanating from the wing and the fuselage will impinge on the twin fins (required for directional stability) causing excessive buffet loads, in some circumstances, to be applied to the aircraft. These loads result in oscillatory stresses, which may cause significant amounts of fatigue damage. Active control is a possible solution to this important problem. A full-scale test was carried out on an F/A-18 fuselage and fins using piezoceramic actuators to control the vibrations. Buffet loads were simulated using very powerful electromagnetic shakers. The first phase of this test was concerned with the open loop system identification whereas the second stage involved implementing linear time invariant control laws. This paper looks at some of the problems encountered as well as the corresponding solutions and some results. It is expected that flight trials of a similar control system to alleviate buffet will occur as early as 2001.

  19. Visualization and analysis of occlusion for human jaws using a "functionally generated path"

    NASA Astrophysics Data System (ADS)

    Myszkowski, Karol; Herder, Jens; Kunii, Tosiyasu L.; Ibusuki, Masumi

    1996-03-01

    Dynamic characteristics of occlusion during lower jaw motion are useful in the diagnosis of jaw articulation problems and in computer-aided design/ manufacture of teeth restorations. The Functionally Generated Path (FGP), produced as a surface which envelops the actual occlusal surface of the moving opponent jaw, can be used for compact representation of dynamic occlusal relations. In traditional dentistry FGP is recorded as a bite impression in a patient's mouth. We propose an efficient computerized technique for FGP reconstruction and validate it through implementation and testing. The distance maps between occlusal surfaces of jaws, calculated for multiple projection directions and accumulated for mandibular motion, provide information for FGP computation. Rasterizing graphics hardware is used for fast calculation of the distance maps. Real-world data are used: the scanned shape of teeth and the measured motion of the lower jaw. We show applications of FGP to analysis of the occlusion relations and occlusal surface design for restorations.

  20. Sinusoidal Obstruction Syndrome (Hepatic Veno-Occlusive Disease)

    PubMed Central

    Fan, Cathy Q.; Crawford, James M.

    2014-01-01

    Hepatic sinusoidal obstruction syndrome (SOS) is an obliterative venulitis of the terminal hepatic venules, which in its more severe forms imparts a high risk of mortality. SOS, also known as veno-occlusive disease (VOD), occurs as a result of cytoreductive therapy prior to hematopoietic stem cell transplantation (HSCT), following oxaliplatin-containing adjuvant or neoadjuvant chemotherapy for colorectal carcinoma metastatic to the liver and treated by partial hepatectomy, in patients taking pyrrolizidine alkaloid-containing herbal remedies, and in other particular settings such as the autosomal recessive condition of veno-occlusive disease with immunodeficiency (VODI). A central pathogenic event is toxic destruction of hepatic sinusoidal endothelial cells (SEC), with sloughing and downstream occlusion of terminal hepatic venules. Contributing factors are SEC glutathione depletion, nitric oxide depletion, increased intrahepatic expression of matrix metalloproteinases and vascular endothelial growth factor (VEGF), and activation of clotting factors. The clinical presentation of SOS includes jaundice, development of right upper-quadrant pain and tender hepatomegaly, ascites, and unexplained weight gain. Owing to the potentially critical condition of these patients, transjugular biopsy may be the preferred route for liver biopsy to exclude other potential causes of liver dysfunction and to establish a diagnosis of SOS. Treatment includes rigorous fluid management so as to avoid excessive fluid overload while avoiding too rapid diuresis or pericentesis, potential use of pharmaceutics such as defibrotide, coagulolytic agents, or methylprednisolone, and liver transplantation. Proposed strategies for prevention and prophylaxis include reduced-intensity conditioning radiation for HSCT, treatment with ursodeoxycholic acid, and inclusion of bevacizumab with oxaliplatin-based chemotherapeutic regimes. While significant progress has been made in understanding the pathogenesis

  1. Robust Lane Sensing and Departure Warning under Shadows and Occlusions

    PubMed Central

    Tapia-Espinoza, Rodolfo; Torres-Torriti, Miguel

    2013-01-01

    A prerequisite for any system that enhances drivers' awareness of road conditions and threatening situations is the correct sensing of the road geometry and the vehicle's relative pose with respect to the lane despite shadows and occlusions. In this paper we propose an approach for lane segmentation and tracking that is robust to varying shadows and occlusions. The approach involves color-based clustering, the use of MSAC for outlier removal and curvature estimation, and also the tracking of lane boundaries. Lane boundaries are modeled as planar curves residing in 3D-space using an inverse perspective mapping, instead of the traditional tracking of lanes in the image space, i.e., the segmented lane boundary points are 3D points in a coordinate frame fixed to the vehicle that have a depth component and belong to a plane tangent to the vehicle's wheels, rather than 2D points in the image space without depth information. The measurement noise and disturbances due to vehicle vibrations are reduced using an extended Kalman filter that involves a 6-DOF motion model for the vehicle, as well as measurements about the road's banking and slope angles. Additional contributions of the paper include: (i) the comparison of textural features obtained from a bank of Gabor filters and from a GMRF model; and (ii) the experimental validation of the quadratic and cubic approximations to the clothoid model for the lane boundaries. The results show that the proposed approach performs better than the traditional gradient-based approach under different levels of difficulty caused by shadows and occlusions. PMID:23478598

  2. Sinusoidal obstruction syndrome (hepatic veno-occlusive disease).

    PubMed

    Fan, Cathy Q; Crawford, James M

    2014-12-01

    Hepatic sinusoidal obstruction syndrome (SOS) is an obliterative venulitis of the terminal hepatic venules, which in its more severe forms imparts a high risk of mortality. SOS, also known as veno-occlusive disease (VOD), occurs as a result of cytoreductive therapy prior to hematopoietic stem cell transplantation (HSCT), following oxaliplatin-containing adjuvant or neoadjuvant chemotherapy for colorectal carcinoma metastatic to the liver and treated by partial hepatectomy, in patients taking pyrrolizidine alkaloid-containing herbal remedies, and in other particular settings such as the autosomal recessive condition of veno-occlusive disease with immunodeficiency (VODI). A central pathogenic event is toxic destruction of hepatic sinusoidal endothelial cells (SEC), with sloughing and downstream occlusion of terminal hepatic venules. Contributing factors are SEC glutathione depletion, nitric oxide depletion, increased intrahepatic expression of matrix metalloproteinases and vascular endothelial growth factor (VEGF), and activation of clotting factors. The clinical presentation of SOS includes jaundice, development of right upper-quadrant pain and tender hepatomegaly, ascites, and unexplained weight gain. Owing to the potentially critical condition of these patients, transjugular biopsy may be the preferred route for liver biopsy to exclude other potential causes of liver dysfunction and to establish a diagnosis of SOS. Treatment includes rigorous fluid management so as to avoid excessive fluid overload while avoiding too rapid diuresis or pericentesis, potential use of pharmaceutics such as defibrotide, coagulolytic agents, or methylprednisolone, and liver transplantation. Proposed strategies for prevention and prophylaxis include reduced-intensity conditioning radiation for HSCT, treatment with ursodeoxycholic acid, and inclusion of bevacizumab with oxaliplatin-based chemotherapeutic regimes. While significant progress has been made in understanding the pathogenesis

  3. Anti-VEGF Therapy for Retinal Vein Occlusions.

    PubMed

    Campa, Claudio; Alivernini, Giuseppe; Bolletta, Elena; Parodi, Maurizio Battaglia; Perri, Paolo

    2016-01-01

    Retinal vein occlusion (RVO) is the second most common cause of visual loss in the Western World. RVO is usually classified into branch RVO (BRVO) and central RVO (CRVO) according to the anatomical site of the vascular occlusion. The pathogenesis of RVO is not yet fully understood, however an important event is the intraluminal thrombus formation, which is usually secondary to several conditions such as hypertension, hyperlipidemia, diabetes and thrombophilia. The blockage of venous circulation causes an elevation of intraluminal pressure in the capillaries, leading to hemorrhages and leakage of fluid within the retina, increase of interstitial pressure and a consequent reduction of retinal perfusion. Ischemia may develop resulting in secretion of vascular endothelial growth factor (VEGF) that causes further vascular leakage and retinal oedema. VEGF has therefore a leading role in RVO pathogenesis and symptoms. As a consequence use of anti-VEGF agents by intravitreal injections has become very common with the aim to improve the clinical outcomes in these patients. Currently 2 anti-VEGF agents (ranimizumab and aflibercept) have been FDA (Food and Drug Administration) and EMA (European Medicine Agency) approved for the treatment of RVO, while another VEGF inhibitor (bevacizumab) is often used "off-label" in clinical practice. Many treatment regimens have been suggested in the clinical trials with these drugs, as monthly injections or injections when needed, however the ideal regimen has not been defined yet. We conducted a systematic review searching MEDLINE for the following terms: retinal vein occlusion, ranibizumab, bevacizumab, aflibercept, vascular endothelial growth factor, macular oedema. Data were extracted by one author (AG and BE) and checked by a second (BPM, CC). Aim of this article was to review available data for each drug, focusing on their efficacy and safety trying to compare their advantages and limits.

  4. Emergency Stenting of Unprotected Left Main Coronary Artery after Acute Catheter-Induced Occlusive Dissection

    PubMed Central

    Akgul, Ferit; Batyraliev, Talantbek; Besnili, Fikret; Karben, Zarema

    2006-01-01

    Left main coronary artery dissection occurs very rarely during selective coronary angiography, but it generally progresses to complete coronary occlusion. The traditional treatment of occlusive dissection of the unprotected left main coronary artery has been surgical. Percutaneous treatment has been sporadic and controversial. We report a case of iatrogenic occlusive dissection of the unprotected left main coronary artery during diagnostic coronary angiography, followed by successful stenting of the lesion. PMID:17215985

  5. Effect of Helmet Pads on the Load Transfer to Head under Blast Loadings

    DTIC Science & Technology

    2015-06-01

    boundary conditions are applied to the head . For longer response duration, appropriate boundary conditions need to be applied to represent the neck ...ARL-RP-0525 ● JUNE 2015 US Army Research Laboratory Effect of Helmet Pads on the Load Transfer to Head under Blast Loadings...ARL-RP-0525 ● JUNE 2015 US Army Research Laboratory Effect of Helmet Pads on the Load Transfer to Head under Blast

  6. Growth and hemodynamics after early embryonic aortic arch occlusion.

    PubMed

    Lindsey, Stephanie E; Menon, Prahlad G; Kowalski, William J; Shekhar, Akshay; Yalcin, Huseyin C; Nishimura, Nozomi; Schaffer, Chris B; Butcher, Jonathan T; Pekkan, Kerem

    2015-08-01

    The majority of severe clinically significant forms of congenital heart disease (CHD) are associated with great artery lesions, including hypoplastic, double, right or interrupted aortic arch morphologies. While fetal and neonatal interventions are advancing, their potential ability to restore cardiac function, optimal timing, location, and intensity required for intervention remain largely unknown. Here, we combine computational fluid dynamics (CFD) simulations with in vivo experiments to test how individual pharyngeal arch artery hemodynamics alter as a result of local interventions obstructing individual arch artery flow. Simulated isolated occlusions within each pharyngeal arch artery were created with image-derived three-dimensional (3D) reconstructions of normal chick pharyngeal arch anatomy at Hamburger-Hamilton (HH) developmental stages HH18 and HH24. Acute flow redistributions were then computed using in vivo measured subject-specific aortic sinus inflow velocity profiles. A kinematic vascular growth-rendering algorithm was then developed and implemented to test the role of changing local wall shear stress patterns in downstream 3D morphogenesis of arch arteries. CFD simulations predicted that altered pressure gradients and flow redistributions were most sensitive to occlusion of the IVth arches. To evaluate these simulations experimentally, a novel in vivo experimental model of pharyngeal arch occlusion was developed and implemented using two-photon microscopy-guided femtosecond laser-based photodisruption surgery. The right IVth arch was occluded at HH18, and resulting diameter changes were followed for up to 24 h. Pharyngeal arch diameter responses to acute hemodynamic changes were predicted qualitatively but poorly quantitatively. Chronic growth and adaptation to hemodynamic changes, however, were predicted in a subset of arches. Our findings suggest that this complex biodynamic process is governed through more complex forms of mechanobiological

  7. Idiopathic Isolated Cilioretinal Artery Occlusion Treated with Hyperbaric Oxygen Therapy

    PubMed Central

    Aktaş, Serdar; Uyar, Osman Murat; Özer, Erol; Aktaş, Hatice; Eltutar, Kadir

    2016-01-01

    Cilioretinal artery occlusion (CLRAO) is a rare event which has been reported in association with various systemic diseases. We report a case of idiopathic isolated CLRAO treated successfully with hyperbaric oxygen (HBO) therapy. A 26-year-old man presented with sudden, painless vision loss and an inferior hemivisual field defect in the left eye. Fundus fluorescein angiography revealed an occluded cilioretinal artery. After 2 weeks of HBO therapy, visual acuity improved from 20/200 to 20/20. The visual field defect improved. PMID:28058169

  8. Growth and hemodynamics after early embryonic aortic arch occlusion*

    PubMed Central

    Lindsey, Stephanie E.; Menon, Prahlad G.; Kowalski, William J.; Shekhar, Akshay; Yalcin, Huseyin C.; Nishimura, Nozomi; Schaffer, Chris B.; Butcher, Jonathan T.; Pekkan, Kerem

    2015-01-01

    The majority of severe clinically significant forms of congenital heart disease (CHD) is associated with great artery lesions, including hypoplastic, double, right or interrupted aortic arch morphologies. While fetal and neonatal interventions are advancing, their potential ability to restore cardiac function, optimal timing, location, and intensity required for intervention remain largely unknown. We here combine computational fluid dynamics (CFD) simulations with in vivo experiments to test how individual pharyngeal arch artery hemodynamics alters as a result of local interventions to obstruct individual arch artery flow. Simulated isolated occlusions within each pharyngeal arch artery were created with image derived three-dimensional (3D) reconstructions of normal chick pharyngeal arch anatomy at Hamburger-Hamilton (HH) developmental stages HH18 and HH24. Acute flow redistributions were then computed using in vivo measured subject-specific aortic sinus inflow velocity profiles. A kinematic vascular growth-rendering algorithm was then developed and implemented to test the role of changing local wall shear stress patterns in downstream 3D morphogenesis of arch arteries. CFD simulations predicted that altered pressure gradients and flow redistributions were most sensitive to occlusion of the IVth arches. To evaluate these simulations experimentally, a novel in vivo experimental model of pharyngeal arch occlusion was developed and implemented using two-photon microscopy guided femtosecond laser based photodisruption surgery. The right IVth arch was occluded at HH18, and resulting diameter changes were followed for up to 24 hours. Pharyngeal arch diameter responses to acute hemodynamic changes were predicted qualitatively but poorly quantitatively. Chronic growth and adaptation to hemodynamic changes however were predicted in a subset of arches. Our findings suggest that this complex biodynamic process is governed through more complex forms of mechanobiological

  9. Innovative advanced occlusion planning with superimposed CT and optical scans.

    PubMed

    Tremblay, Gilbert

    2011-04-01

    In order to increase the likelihood of a successful treatment plan outcome, it is critical to be able to effectively view the patient's underlying bony skeletal relationship of his or her TMJ. An innovative approach suggested to achieve this is to use the CT scan, optical scan, and Kois deprogrammer. Once the vertical dimension has been increased, the novelty of this approach is the ability to superimpose both scans along with the Kois deprogrammer and, using computer software, evaluate the TMJ position in three dimensions. This case presentation describes how TMJ CT scan evaluation is used in planning a complex rehabilitation case, given that the occlusion structures can be visualized independently and interactively.

  10. Total occlusion of left main coronary artery without angina pectoris.

    PubMed

    DePace, N L; Kimbiris, D; Iskandrian, A S; Bemis, C E; Segal, B L

    1983-05-01

    A patient had total occlusion of the left main coronary artery that was proved by coronary arteriography. The patient was initially seen with clinical signs of congestive heart failure but without symptoms of angina pectoris or ECG evidence of myocardial infarction. The patient's extensive right-to-left coronary artery collaterals may have contributed to the absence of chest pain. Because of the severe left ventricular dysfunction and the absence of chest pain, the patient was treated with medical therapy. Six months after the cardiac catheterization, he was alive and well under New York Heart Association functional classification II.

  11. The ABCs of RVO: a review of retinal venous occlusion.

    PubMed

    MacDonald, Derek

    2014-07-01

    Retinal vein occlusions are important causes of loss of vision; indeed, they are the second most common retinal vascular disease, following diabetic retinopathy. For this reason alone, primary eye-care providers must be well versed in diagnosis and management. Risk factors, though not universally agreed upon, include but are not limited to advancing age, systemic hypertension, arteriolarsclerosis, diabetes, hyperlipidaemia, blood hyperviscosity, thrombophilia, ocular hypertension and glaucoma. Typically, visual loss is secondary to macular oedema and/or retinal ischaemia. Treatment modalities have included observation, systemic thrombolysis and haemodilution, radial optic neurotomy, chorioretinal anastomosis, vitrectomy, laser photocoagulation and intravitreal injection of anti-inflammatory and, most recently, anti-vascular endothelial growth factors.

  12. [Abrasion measurements in vivo in occlusal composite and amalgam fillings].

    PubMed

    Meier, C; Lutz, F

    1978-09-01

    A new method for quantitative measurement of occlusal wear on restorations is described. In a clinical evaluation with four different composites and an amalgam the method proved to be simple in execution and very exact. Statistical analysis after 7 months has shown significant differences in wear resistance of the different materials. The nature of the resulting wear was electron optically examined. Typical structural surface characteristics were observed for each of the different materials. More recently developed composities utilizing extremly small filler particles (Aerosil) seem to be comparable to amalgam in wear resistance.

  13. Effects of hypercapnia and inspiratory flow-resistive loading on respiratory activity in chronic airways obstruction.

    PubMed Central

    Altose, M D; McCauley, W C; Kelsen, S G; Cherniack, N S

    1977-01-01

    The respiratory responses to hypercapnia alone and to hypercapnia and flow-resistive loading during inspiration were studied in normal individuals and in eucapnic and hypercapnic patients with chronic airways obstruction. Responses were assessed in terms of minute ventilation and occlusion pressure (mouth pressure during airway occlusion 100 ms after the onset of inspiration). Ventilatory responses to CO2 (deltaV/deltaPCO2) were distinctly subnormal in both groups of patients with airways obstruction. The two groups of patients, however, showed different occlusion pressure responses to CO2 (deltaP100/deltaPCO2): deltaP100/deltaPCO2 was normal in the eucapnic patients but subnormal in the hypercapnic patients. Flow-resistive loading during inspiration reduced deltaV/deltaPCO2 both in normal subjects and in patients with airways obstruction. The occlusion pressure response to CO2 increased in normal subjects during flow-resistive loading but remained unchanged in both groups of patients with chronic airways obstruction. These results indicate that while chemosensitivity as determined by deltaP100/deltaPCO2 is impaired only in hypercapnic patients with chronic airways obstruction, an acute increase in flow resistance elicits a subnormal increase in respiratory efferent activity in both eucapnic and hypercapnic patients. PMID:838862

  14. A New Occlusion Device: Application of the ArtVentive Endoluminal Occlusion System (EOS)—First in Human Clinical Trial

    SciTech Connect

    Venbrux, Anthony C.; Rudakov, Leon; Plass, Andre Emmert, Maximilian Y.; Ebner, Adrian

    2013-05-24

    PurposeThe purpose of this study was to determine the safety and efficacy of a new endoluminal occlusion device, ArtVentive endoluminal occlusion system (EOS), to occlude the spermatic vein in symptomatic males with varicoceles.MethodsThe ArtVentive EOS device has been developed for percutaneous, peripheral occlusion of the peripheral arterial and venous vasculature. The system is comprised of an implantable occlusion device and a delivery catheter. At present, there are two device sizes: (a) size 1 for target vessels ranging between 3.5 and 5.5 mm in diameter, and (b) size 2 for target vessels 5.5–8.5 mm in diameter. The treatment group included six adult males, ages 22–34 years. Nine target vessels were occluded. A total of 20 devices were implanted in six subjects.ResultsThe acute occlusion rate at the end of the procedure was 100 % occurring in nine of nine vessels. The spermatic veins of all patients remained occluded on venography at 30 days follow-up. Pain scores related to varicoceles decreased in five of six patients.ConclusionsAlthough we recognize this study is limited, initial experience indicates that the ArtVentive EOS is a safe and effective new device for occlusion of vessels (varicoceles). The device has potential applications in other clinical conditions requiring occlusion of veins or arteries.

  15. Minimally invasive per-catheter occlusion and dilation procedures for congenital cardiovascular abnormalities in dogs.

    PubMed

    Tobias, Anthony H; Stauthammer, Christopher D

    2010-07-01

    With ever-increasing sophistication of veterinary cardiology, minimally invasive per-catheter occlusion and dilation procedures for the treatment of various congenital cardiovascular abnormalities in dogs have become not only available, but mainstream. Much new information about minimally invasive per-catheter patent ductus arteriosus occlusion has been published and presented during the past few years. Consequently, patent ductus arteriosus occlusion is the primary focus of this article. Occlusion of other less common congenital cardiac defects is also briefly reviewed. Balloon dilation of pulmonic stenosis, as well as other congenital obstructive cardiovascular abnormalities is discussed in the latter part of the article.

  16. The evolution of human occlusion--ancient clinical tips for modern dentists.

    PubMed

    Neiburger, E J

    2002-01-01

    Man evolved in an environment in which the occlusion was worn down quickly, resulting in flattened occlusal and interproximal surfaces. This rapid wear reduced occlusal decay, traumatic occlusion, malaligned teeth, impactions, and temporomandibular disease (TMD). In the last 250 years, however, new food production techniques created an environment that was less dentally abrasive than earlier diets. Teeth were not worn down as programmed in our "evolutionary blue-print." This lack of wear resulted in increased caries, cusp fractures, bruxing, malocclusion, periodontal disease, and TMD. A practical re-creation of ancient dental wear patterns can help to reduce these modern dental diseases.

  17. Parameter on occlusal traumatism in patients with chronic periodontitis. American Academy of Periodontology.

    PubMed

    2000-05-01

    The American Academy of Periodontology has developed the following parameter on occlusal traumatism in patients with chronic periodontitis. Occlusal therapy is an integral part of periodontal therapy. Patients should be informed about the occlusal problem, therapeutic alternatives, potential complications, expected results, and their responsibility in treatment. Consequences of no treatment should be explained. Failure to treat occlusal traumatism appropriately in patients with chronic periodontitis may result in progressive loss of bone and an adverse change in prognosis, and could result in tooth loss. Given this information, patients should then be able to make informed decisions regarding their periodontal therapy.

  18. Bilateral internal carotid artery occlusion associated with the antiphospholipid antibody syndrome.

    PubMed

    Anand, Pria; Mann, Sharan K; Fischbein, Nancy J; Lansberg, Maarten G

    2014-01-01

    A 39-year-old woman presented with a right-hemispheric stroke 1 year after she had suffered a left-hemispheric stroke. Her diagnostic workup was notable for bilateral occlusions of the internal carotid arteries at their origins and a positive lupus anticoagulant antibody test. There was no evidence of carotid dissection or another identifiable cause for her carotid occlusions. These findings suggest that the antiphospholipid antibody syndrome may be implicated in the pathological changes that resulted in occlusions of the extracranial internal carotid arteries. Young stroke patients who present with unexplained internal carotid artery occlusions may benefit from testing for the presence of antiphospholipid antibodies.

  19. Bilateral Internal Carotid Artery Occlusion Associated with the Antiphospholipid Antibody Syndrome

    PubMed Central

    Anand, Pria; Mann, Sharan K.; Fischbein, Nancy J.; Lansberg, Maarten G.

    2014-01-01

    A 39-year-old woman presented with a right-hemispheric stroke 1 year after she had suffered a left-hemispheric stroke. Her diagnostic workup was notable for bilateral occlusions of the internal carotid arteries at their origins and a positive lupus anticoagulant antibody test. There was no evidence of carotid dissection or another identifiable cause for her carotid occlusions. These findings suggest that the antiphospholipid antibody syndrome may be implicated in the pathological changes that resulted in occlusions of the extracranial internal carotid arteries. Young stroke patients who present with unexplained internal carotid artery occlusions may benefit from testing for the presence of antiphospholipid antibodies. PMID:24707268

  20. Applied geodesy

    SciTech Connect

    Turner, S.

    1987-01-01

    This volume is based on the proceedings of the CERN Accelerator School's course on Applied Geodesy for Particle Accelerators held in April 1986. The purpose was to record and disseminate the knowledge gained in recent years on the geodesy of accelerators and other large systems. The latest methods for positioning equipment to sub-millimetric accuracy in deep underground tunnels several tens of kilometers long are described, as well as such sophisticated techniques as the Navstar Global Positioning System and the Terrameter. Automation of better known instruments such as the gyroscope and Distinvar is also treated along with the highly evolved treatment of components in a modern accelerator. Use of the methods described can be of great benefit in many areas of research and industrial geodesy such as surveying, nautical and aeronautical engineering, astronomical radio-interferometry, metrology of large components, deformation studies, etc.

  1. Estimation of Unattenuated Factor Loadings.

    ERIC Educational Resources Information Center

    Woodward, Todd S.; Hunter, Michael A.

    1999-01-01

    Demonstrates that traditional exploratory factor analytic methods, when applied to correlation matrices, cannot be used to estimate unattenuated factor loadings. Presents a mathematical basis for the accurate estimation of such values when the disattenuated correlation matrix or the covariance matrix is used as input. Explains how the equations…

  2. Review of clinical EMG studies related to muscle and occlusal factors in healthy and TMD subjects.

    PubMed

    Suvinen, T I; Kemppainen, P

    2007-09-01

    Several electronic instruments have been developed as adjuncts to objectively record the dysfunctional features of temporomandibular disorders and to study the effectiveness of various treatment interventions. The aim of this review was to assess the value and contribution of clinical electromyographic research in the understanding of asymptomatic and dysfunctional muscle function and the therapeutic effects of interocclusal appliances. For this purpose MedLine and PubMed searches were conducted with the following main keywords alone and in various combinations: electromyography, muscles of mastication, masseter, temporalis, temporomandibular, TMD, utility, validity, repeatability, rest, postural, vertical dimension, occlusal, splint, treatment. The review includes critical evaluation, discussion and conclusions regarding electromyographic studies in asymptomatic and dysfunctional muscles, rest position, occlusal parameters and interocclusal appliances, as well as a critical summary and proposals for further research. Much of earlier critique of many electromyographic studies still applies regarding comparative sample selections, research designs, analyses and conclusions. The areas not well-understood include normal biological variation, capacity for adaptation, fluctuations regarding the clinical course and multidimensional features of temporomandibular disorders and long-term follow-up data, especially in studies that evaluate the effectiveness of therapeutic measures. Considering the required improvements in technical and research designs features and critical appraisal electromyographic research could have value as an adjunct research tool to study features of craniofacial muscle-related dysfunction. Until electromyographic measures are correlated with other multidimensional, especially subjective and pain-related methods, the clinical use of this method for diagnostic purposes of temporomandibular disorders remains in doubt, and is not at present recommended.

  3. A case of veno-occlusive disease following liver transplantation.

    PubMed

    Chen, Hong; Wang, Xu; Fan, Tieyan; Li, Jun; Wang, Letian; Shen, Zhongyang

    2014-01-01

    The present case report describes the diagnosis and treatment of a patient with veno-occlusive disease (VOD) following liver transplantation. Combining the clinical data and relevant literature, the study aimed to consider the causes of VOD following liver transplantation, and the pathogenesis, clinical diagnosis and auxiliary examination features of VOD. A 42-year-old man who had a long history of taking traditional Chinese medicine (essential components unknown) underwent an orthotropic liver transplantation on January 14, 2011, due to small venous occlusion disease of the liver. The patient was treated with tacrolimus as an antirejection therapy following the surgery, and gradually developed right upper quadrant pain and fatigue. The examination results were consistent with the diagnostic standards for VOD. Following treatment with methylprednisolone, the patient was treated with alprostadil and Danhong injections. Forty days later, the patient's total bilirubin (TBIL) level was observed to have decreased significantly, the liver function had returned to normal and the ascites had decreased, but had not completely disappeared. The patient then underwent a transjugular intrahepatic portosystemic shunt (TIPS) procedure, following which the ascites were shown to have completely disappeared.

  4. Chronic total occlusion: To treat or not to treat

    PubMed Central

    Bardají, Alfredo; Rodriguez-López, Judit; Torres-Sánchez, Mauricio

    2014-01-01

    Over the last two decades, there has been increasing interest in new techniques for the percutaneous treatment of coronary chronic total occlusions (CTO), which have a success rate that is much higher than that of a few years ago. The rise in percutaneous treatment for these lesions is due to its ability to improve the symptoms and prognosis of patients in the chronic and stable phase of coronary disease. Current data suggest that successful percutaneous coronary intervention for CTO is associated with improvement in patient symptoms, quality of life, left ventricular function, and survival, compared with those with unsuccessful CTO PCI. However, all the scientific evidence supporting this treatment comes from observational studies, and no randomized study comparing percutaneous treatment with medical treatment has yet been published. A major limitation of these studies is their observational design, with limited information with regard to potential baseline differences between the successful vs unsuccessful cohorts. Pending randomized studies, patients should be selected very carefully, especially if they are asymptomatic or very few symptoms, and the benefits obtained in terms of complications during the procedure, the quality of life obtained and further ischemic events avoided should be evaluated systematically. In this review, we will consider the available information supporting percutaneous treatment for chronic occlusions, as well as the areas of uncertainty where more research projects are required. PMID:25068022

  5. Prevalence of Orthodontic Treatment Need and Occlusal Traits in Schoolchildren.

    PubMed

    Jamilian, Abdolreza; Darnahal, Alireza; Damani, Elnaz; Talaeipour, Maziar; Kamali, Zinat

    2014-01-01

    Background. Widespread use of the IOTN along with detailed study of occlusal traits is suitable for planning community dental health resources. Objectives. The aim of current study was to assess the need for orthodontic treatment among school children of Tehran by means of the Dental Health Component (DHC) of the Index of Orthodontic Treatment Need (IOTN) and also to evaluate the occlusal traits of the subjects. Methods. 684 (343 boys and 341 girls) school children, 15 to 17 years of age, were selected at random from 12 schools to represent the four main areas of Tehran. The final sample who met the inclusion criteria comprised 643 subjects (322 males and 321 females). Malocclusion was determined with the Index of Orthodontic Treatment Need. The IOTN grades were statistically compared in the two genders using chi-square test. Results. Orthodontic treatment need, using the DHC, was found in only 9.0 per cent of the children. The prevalence of Angle Class I malocclusion in this study was higher than other malocclusions (65.2 per cent), followed by crowding in 62.7 per cent of the subjects. Conclusion. Orthodontic treatment need for Tehran high school students was relatively lower than that reported in most recent studies in Europe.

  6. Distribution of sagittal occlusal relationships in different stages of dentition.

    PubMed

    Emine, Kaygisiz; Lale, Taner; Kahraman, Gungor

    2015-01-01

    The aim of this study was to assess the distribution of sagittal occlusal relationships in different dentition periods in a Turkish sample group. In total, 1,110 patients (561 females, 549 males) aged 4.6-23 years were randomly chosen after intraoral clinical examination. The subjects were classified according to their sagittal occlusal relationships and four dentition stages -deciduous, early mixed, late mixed, and permanent dentition. The statistical significance of the occurrence of malocclusion types in dentition stages was evaluated by Chi-square and Fischer's exact tests. Class I malocclusion was observed at the highest rate in all dentition stages. Class III malocclusion was observed at the highest rate in the permanent dentition, whereas Class II malocclusion was observed at the highest rate in the late mixed dentition. The rates of Class I, II, and III malocclusions were similar in males and females. Our study reveals that the prevalence of malocclusion and need for orthodontic treatment has increased in the population towards the permanent dentition.

  7. Non-occlusive mesenteric ischaemia of a free jejunal flap.

    PubMed

    Onoda, Satoshi; Kimata, Yoshihiro; Yamada, Kiyoshi; Koshimune, Seijiro; Onoda, Tomoo; Shirakawa, Yasuhiro

    2013-05-01

    Free jejunal transfer using microsurgery after oesophageal or pharyngeal cancer resection is a useful operative approach. However, the disadvantage of free tissue transfer is the risk of necrosis of the transferred tissue due to impaired blood supply. In addition, jejunal flaps are more prone to blood-flow disorders such as ischaemia and congestion compared with other types of flaps. The causes of local blood supply disorders after microsurgery are divided broadly into two classes: one is thrombosis of an artery and/or vein in the anastomotic region and the other consists of local physical factors such as compressive pressure derived from haematoma formation and the effect of infection of the vascular pedicle. In this report, two rare cases of blood-flow disorder of the transferred free jejunum are described. In both cases, no signs of significant infection or occlusion of the vascular pedicles were present and late necrosis progressed gradually. The patients showed remarkable weight loss and a poor nutritional state due to inadequate preoperative nutritional intake. The necrosis was considered to be a result of non-occlusive mesenteric ischaemia of a free jejunal flap, and the factors contributing to free jejunal necrosis were reviewed.

  8. Initial experience with hysteroscopic tubal occlusion (Essure®)

    PubMed Central

    Depes, Daniella De Batista; Pereira, Ana Maria Gomes; Lippi, Umberto Gazi; Martins, João Alfredo; Lopes, Reginaldo Guedes Coelho

    2016-01-01

    ABSTRACT Objective To evaluate results of early tubal occlusions performed by hysteroscopy (Essure®). Methods This prospective study included 38 patients, 73.7% of them were white, mean age 34.5 years, they have had on average 3 pregnancies and 2.7 of deliveries. A total of 86.8% of patients previously prepared the endometrium. All procedures were carried out at outpatient unit without anesthesia. Results Insertion rate of the device was 100% at a mean time of 4 minutes and 50 seconds. Based on the analogical visual scale, average pain reported was three, and 55.3% of women did not report pain after the procedure. After 3 months, 89.5% of patients were very satisfied with the method. Simple radiographs of the pelvis showed 92.1% of topical devices, and one case of unilateral expulsion had occurred. A four years follow-up did not show failure in the method. Conclusions Tubal occlusion through hysteroscopy at outpatient unit and without anesthesia was a quickly and well-tolerated procedure. No serious complications were seen, the success rate was high, and patients were satisfied. PMID:27462885

  9. Occlusal force transfer by removable partial denture designs for a radical maxillectomy.

    PubMed

    Schwartzman, B; Caputo, A; Beumer, J

    1985-09-01

    Several removable partial denture retainers were tested on a photoelastic cast of a human maxilla that had undergone a surgical resection through the midline. The conclusions based on the results of these tests are as follows. Physiologic adjustment of all the designs tested revealed a dramatic reduction in stresses when the framework were placed into position. Under load, the physiologically adjusted frameworks produced less potentially damaging stresses in the supporting structures than the unadjusted frameworks. High stresses were located at the premolar region for all the designs. Lingual retainers produced higher stress concentration than buccal retainers. In the anterior region, the I-bar retainer with a cingulum rest was the best combination for transmitting the occlusal forces along the long axis of the tooth. From the perspective of the equitability of stress transfer, the tested designs from best to worse are infrabulge I-bar retainer, either buccal or lingual retention; light wire circumferential retainer with buccal retention; and the circumferential cast buccal retention, swing-lock system.

  10. Influence of different narrative instructions to record the occlusal contact with silicone registration materials.

    PubMed

    Obara, R; Komiyama, O; Iida, T; Asano, T; De Laat, A; Kawara, M

    2014-03-01

    This study examined the influence of narrative instructions on the occlusal contact area, occlusal contact point and masticatory muscle activities in normal subjects. Twelve healthy men and 12 healthy women with no more than one missing tooth per quadrant participated. Surface EMG was recorded from the masseter and temporal muscle. As a control measurement, intercuspal position was maintained to produce a habitual clenching record (NCR) while the occlusal contact area and occlusal contact point was recorded by means of silicone material. Subsequently, the occlusal contact area was recorded with the narrative instruction for minimum clenching record (MCR), light clenching record (LCR) and strong clenching record (HCR). While the EMG activity (%MVC) increased modestly from MCR to LCR (from 9·3 ± 2·0% to 11·5 ± 1·5%), the occlusal contact area increased rapidly (from 17·2 ± 11·3 mm(2) to 26·8 ± 15·6 mm(2) ) (P < 0·05). Both EMG activity and occlusal contact area increased gradually from LCR to NCR (to 17·7 ± 2·0% and to 31·4 ± 14·2 mm(2) , respectively). Finally, EMG activity still increased from NCR to HCR (to 44·5 ± 3·7%) (P < 0·05), but the occlusal contact area remained stable (to 36·8 ± 16·6 mm(2) ). Occlusal contact points at left posterior, right posterior, anterior and total area were not significantly different between each task. This study showed that narrative instructions while recording the bite can result in largely stable occlusal contact area. An adequate narrative instruction may therefore contribute to taking a stable occlusal recording in natural dentition.

  11. A double-blinded randomized trial testing the tolerability and efficacy of a novel topical agent with and without occlusion for the treatment of cellulite: a study and review of the literature.

    PubMed

    Rao, Jaggi; Paabo, Kristina E; Goldman, Mitchel P

    2004-01-01

    Cellulite is the unsightly dimpling and nodularity frequently found on the thighs and buttocks of post-adolescent women. The anatomy and pathophysiology of this unwanted condition is poorly understood. The paucity of research studies to date has led to a dormancy of scientifically based therapeutic options that are effective and tolerable. The purpose of this study is to evaluate the tolerability and efficacy of a novel topical agent based on a plausible pathophysiologic mechanism in the treatment of cellulite, and to compare the efficacy of this agent used in combination with an occlusive bioceramic-coated neoprene garment, to the agent used alone without occlusion. We will also review the current understanding of the etiology and nature of cellulite and summarize available treatment options. Twenty women with a moderate degree of cellulite were entered into a four-week, double-blinded, randomized trial where an anti-cellulite cream was applied to the affected sites on a nightly basis. Each subject was randomized to receive occlusion by a bioceramic-coated neoprene garment on either the right or left leg, with the contralateral side serving as a control with no occlusion. High-quality digital photography was taken before treatment and after four weeks at various angles, with tangential full-spectrum lighting. Four blinded, independent dermatologist reviewers assessed the photographs for improvement. Subjects completed questionnaire forms to assess tolerability and efficacy. Of the 17 subjects who completed the study, 76% noticed an overall improvement in their cellulite, with 54% reporting greater improvement in the thigh that received garment occlusion. The average measured decrease in thigh circumference was 1.2 cm, noting a 1.3 cm reduction with occlusion and a 1.1 cm reduction without occlusion. Upon review of the pre- and post-study photographs, the dermatologist evaluators found an improvement in 65% of treated legs with occlusion, and 59% of treated legs

  12. Acute thromboembolic occlusion of the superior mesenteric artery following covered stent occlusion in the superior mesenteric artery: endovascular therapy using mechanical rotational thrombectomy.

    PubMed

    Goltz, Jan P; Petritsch, Bernhard; Spor, Leo; Hahn, Dietbert; Kickuth, Ralph

    2012-09-01

    Acute thromboembolic occlusion of the superior mesenteric artery is a rare and often fatal condition in which surgery represents the golden standard in therapy. We present a case in which a patient was treated with covered stent implantation for acute bleeding from the superior mesenteric artery following pancreatic resection, radiation, and embolization of a hepatic artery pseudoaneurysm. Some weeks later clinical signs were suggestive of acute thromboembolic occlusion of the superior mesenteric artery and digital subtraction angiography showed occlusion of the previously implanted covered stents. The patient was successfully treated transfemorally with percutaneous mechanical instent thrombectomy using a 6F Rotarex® catheter. We conclude that in selected cases percutaneous mechanical thrombectomy may represent a minimally-invasive alternative to open surgical thrombectomy for treatment of acute thromboembolic occlusion of the superior mesenteric artery.

  13. 14 CFR 25.509 - Towing loads.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... towing fittings and must act parallel to the ground. In addition— (1) A vertical load factor equal to 1.0...) A reaction with a maximum value equal to the vertical reaction must be applied at the axle of...

  14. 14 CFR 25.509 - Towing loads.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... towing fittings and must act parallel to the ground. In addition— (1) A vertical load factor equal to 1.0...) A reaction with a maximum value equal to the vertical reaction must be applied at the axle of...

  15. 14 CFR 25.509 - Towing loads.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... towing fittings and must act parallel to the ground. In addition— (1) A vertical load factor equal to 1.0...) A reaction with a maximum value equal to the vertical reaction must be applied at the axle of...

  16. 14 CFR 25.509 - Towing loads.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... towing fittings and must act parallel to the ground. In addition— (1) A vertical load factor equal to 1.0...) A reaction with a maximum value equal to the vertical reaction must be applied at the axle of...

  17. 14 CFR 25.509 - Towing loads.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... towing fittings and must act parallel to the ground. In addition— (1) A vertical load factor equal to 1.0...) A reaction with a maximum value equal to the vertical reaction must be applied at the axle of...

  18. Middle Cerebral Artery Occlusion with Moyamoya-Like Vessels and Aneurysms

    PubMed Central

    Rivera, Rodrigo; Sordo, Juan; Badilla, Lautaro; Bravo, Eduardo; Riveros, Rodrigo; Giacaman, Pablo

    2014-01-01

    Summary We describe two cases of aneurysmal rupture in moyamoya-like vessels in middle cerebral artery occlusion. This phenomenon was previously described in severe steno-occlusive disease and accounts for the hemorrhagic presentation. To our knowledge, these are the second and third clinical cases published in modern neuroradiological literature. PMID:24556306

  19. 40 CFR 180.1148 - Occlusion Bodies of the Granulosis Virus of Cydia pomenella; tolerance exemption.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Virus of Cydia pomenella; tolerance exemption. 180.1148 Section 180.1148 Protection of Environment... RESIDUES IN FOOD Exemptions From Tolerances § 180.1148 Occlusion Bodies of the Granulosis Virus of Cydia... of the microbial pest control agent Occlusion Bodies of the Granulosis Virus of Cydia...

  20. 40 CFR 180.1148 - Occlusion Bodies of the Granulosis Virus of Cydia pomenella; tolerance exemption.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Virus of Cydia pomenella; tolerance exemption. 180.1148 Section 180.1148 Protection of Environment... RESIDUES IN FOOD Exemptions From Tolerances § 180.1148 Occlusion Bodies of the Granulosis Virus of Cydia... of the microbial pest control agent Occlusion Bodies of the Granulosis Virus of Cydia...

  1. 40 CFR 180.1148 - Occlusion Bodies of the Granulosis Virus of Cydia pomenella; tolerance exemption.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Virus of Cydia pomenella; tolerance exemption. 180.1148 Section 180.1148 Protection of Environment... RESIDUES IN FOOD Exemptions From Tolerances § 180.1148 Occlusion Bodies of the Granulosis Virus of Cydia... of the microbial pest control agent Occlusion Bodies of the Granulosis Virus of Cydia...

  2. Occlusions in Camera Networks and Vision: The Bridge between Topological Recovery and Metric Reconstruction

    DTIC Science & Technology

    2009-05-18

    sequence of a hand in front of a moving Macbeth board are shown. The detection of occlusions using local topological invariants is made with respect...Detections Figure 7.5: Three consecutive frames from a sequence of a hand in front of a moving Macbeth board are shown. The detection of occlusions using

  3. 40 CFR 180.1148 - Occlusion Bodies of the Granulosis Virus of Cydia pomenella; tolerance exemption.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Virus of Cydia pomenella; tolerance exemption. 180.1148 Section 180.1148 Protection of Environment... RESIDUES IN FOOD Exemptions From Tolerances § 180.1148 Occlusion Bodies of the Granulosis Virus of Cydia... of the microbial pest control agent Occlusion Bodies of the Granulosis Virus of Cydia...

  4. Bilateral renal artery occlusion in a patient with primary antiphospholipid antibody syndrome: thrombosis, vasculitis or both?

    PubMed

    Ames, P R; Cianciaruso, B; Bellizzi, V; Balletta, M; Lubrano, E; Scarpa, R; Brancaccio, V

    1992-11-01

    A 43-year-old man presented with oliguria and hypertension. Renal arteriography showed bilateral renal artery occlusion. Circulating antiphospholipid antibodies were found together with a change in natural anticoagulant plasma levels. Immunofluorescence of examined vessels showed immune complex vasculitis. We discuss the pathogenetic mechanism leading to the development of this rare occlusive event.

  5. The dental occlusion as a suspected cause for TMDs: epidemiological and etiological considerations.

    PubMed

    Türp, J C; Schindler, H

    2012-07-01

    The relationship between the dental occlusion and temporomandibular disorders (TMDs) has been one of the most controversial topics in the dental community. In a large epidemiological cross-sectional survey - the Study of Health in Pomerania (Germany) - associations between 15 occlusion-related variables and TMD signs or symptoms were found. In other investigations, additional occlusal variables were identified. However, statistical associations do not prove causality. By using Hill's nine criteria of causation, it becomes apparent that the evidence of a causal relationship is weak. Only bruxism, loss of posterior support and unilateral posterior crossbite show some consistency across studies. On the other hand, several reported occlusal features appear to be the consequence of TMDs, not their cause. Above all, however, biological plausibility for an occlusal aetiology is often difficult to establish, because TMDs are much more common among women than men. Symptom improvement after insertion of an oral splint or after occlusal adjustment does not prove an occlusal aetiology either, because the amelioration may be due to the change of the appliance-induced intermaxillary relationship. In addition, symptoms often abate even in the absence of therapy. Although patients with a TMD history might have a specific risk for developing TMD signs, it appears more rewarding to focus on non-occlusal features that are known to have a potential for the predisposition, initiation or perpetuation of TMDs.

  6. 40 CFR 180.1148 - Occlusion Bodies of the Granulosis Virus of Cydia pomenella; tolerance exemption.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Virus of Cydia pomenella; tolerance exemption. 180.1148 Section 180.1148 Protection of Environment... RESIDUES IN FOOD Exemptions From Tolerances § 180.1148 Occlusion Bodies of the Granulosis Virus of Cydia... of the microbial pest control agent Occlusion Bodies of the Granulosis Virus of Cydia...

  7. Implications of natural occlusion of ventilated racks on ammonia and sanitation practices.

    PubMed

    Creamer, Michelle A; Petty, Joann; Martin, Tara; Bergdall, Valerie; Hickman-Davis, Judy M

    2014-03-01

    Examination of ventilated rat racks prior to semiannual sanitation revealed silicone nozzles and ventilation ports that were partially or completely occluded with granular debris. We subsequently sought to document performance standards for rack sanitation and investigate the effect of ventilation port occlusion on rack function and animal husbandry practices. We hypothesized that individually ventilated cages with occluded airflow would require more frequent cage changes, comparable to those for static cages (that is, every 3 to 4 d). Sprague-Dawley rats were housed under one of 4 conditions: no airflow occlusion, occluded air-supply inlet, occluded air-exhaust outlet, and occlusion of both inlet and outlet. Cages were changed when daily ammonia concentration exceeded 20 ppm or after 14 d had elapsed. Most cages with unoccluded or partial airflow occlusion remained below the 20 ppm limit until day 12 or 13. Cages with occlusion of both inlet and outlet exceeded 20 ppm ammonia by as early as day 5. Airflow was significantly lower in cages with occlusion of both inlet and outlet airflow. Weekly inspection revealed that occlusion of ventilation ports was detectable by 3 mo after semiannual sanitation. This study demonstrates that silicone nozzles should be removed prior to rack sanitation to improve the effectiveness of cleaning ventilation ports and nozzles. While the rack is in use, silicone nozzles and ventilation ports should be inspected regularly to identify occlusion that is likely to diminish environmental quality in the cage. Intracage ammonia levels are significantly higher when both inlet and outlet airflow are occluded.

  8. Tooth displacement due to occlusal contacts: a three-dimensional finite element study.

    PubMed

    Gomes de Oliveira, S; Seraidarian, P I; Landre, J; Oliveira, D D; Cavalcanti, B N

    2006-12-01

    The use of the Finite Element Method (FE) is an appropriate way to study occlusal forces and tooth movement. The purpose of this study was to evaluate the effects of different occlusal contact patterns on tooth displacement in an adult dentition using a three-dimensional FE model of a human maxilla and mandible. Initially, images of a computerized tomography scan were redrawn in a computer program (CATIA) followed by the FE mesh construction. The MSC/Patran software was used to develop the FE mesh comprising 520,445 elements and 106,633 nodes. The MSC/Nastran program was utilized as pre and post-processor for all mathematical calculations necessary to evaluate dental and mandibular biomechanics. Four occlusal patterns were tested: FEM 1 - standard occlusal contacts; FEM 2 - removal of mesial marginal and mesial tripoidism contacts; FEM 3 - removal of distal marginal and distal tripoidism contacts; FEM 4 - similar to FEM 3 with added contacts between upper and lower incisors. Small changes in the standard distribution of occlusal contacts resulted in an imbalance of occlusal forces and changes in dental positioning. All simulations tested showed mesial displacement of posterior teeth. The most significant changes were registered in the model presenting unstable occlusal contacts when the anterior teeth were in occlusion (FEM 4). These findings may explain mandibular incisors crowding and maxillary incisors flaring as a result of small variations in dental contacts.

  9. Sex Differences in Infants' Mapping of Complex Occlusion Sequences: Further Evidence

    ERIC Educational Resources Information Center

    Wilcox, Teresa

    2007-01-01

    Recently, infant researchers have reported sex differences in infants' capacity to map their representation of an occlusion sequence onto a subsequent no-occlusion display. The research reported here sought to identify the extent to which these sex differences are observed in event-mapping tasks and to identify the underlying basis for these…

  10. Association between occlusal force and physical functions in preschool children: a comparison of males and females

    PubMed Central

    Hirao, Aya; Murata, Shin; Kubo, Atsuko; Hachiya, Mizuki; Mitsumaru, Nozomi; Asami, Toyoko

    2015-01-01

    [Purpose] To determine and compare changes over time in the physical strength of male and female children aged 4–5 years by measuring physical functions such as occlusal forces. [Subjects and Methods] The occlusal force, weight, height, grip strength, standing long jump, ball throwing, timed up and go (TUG), and the 25-m run time were measured of 331 children to determine their physical strength. All the children understood and were capable of completing all tests. [Results] Occlusal force among male infants significantly correlated with all items except ball throwing. Stepwise multiple regression analysis independently associated occlusal force with grip strength. In contrast, occlusal force of female infants significantly correlated with all the tested items. Stepwise multiple regression analysis also independently associated occlusal force with grip strength and TUG in females. [Conclusion] Grip strength indicating upper-limb muscle strength correlated with occlusal forces in both male and female children, whereas TUG, balance and walking ability indicating muscle strength of the lower limbs, correlated with items relevant to everyday functions in female infants. These findings show that different factors are involved in the occlusal forces of male and female children. PMID:26834340

  11. Scoliosis and dental occlusion: a review of the literature

    PubMed Central

    2011-01-01

    Background Idiopathic scoliosis is a deformity without clear etiology. It is unclear wether there is an association between malocclusion and scoliosis. Several types of occlusion were described in subjects with scoliosis, mostly case-reports. Objectives The aim of this review was to evaluate the type of occluslins more prevalent in subjects with scoliosis Search strategy All randomised and controlled clinical trials identified from the Cochrane Oral Health Group Trials Register, a MEDLINE search using the Mesh term scoliosis, malocclusion, and relevant free text words, and the bibliographies of papers and review articles which reported the outcome of orthodontic treatment in subjects with scoliosis that were published as abstracts or papers between 1970 and 2010. Selection criteria All randomised and controlled clinical trials published as full papers or abstracts which reported quantitative data on the outcomes malocclusion in subjects with scoliosis. Data collection and analysis Data were extracted without blinding to the authors, age of patients or type of occlusion. Main results Using the search strategy eleven observational longitudinal studies were identified. No randomized clinical trials were recorded. Twenty-three cross-sectional studies were recorderd, and the others studies were reviews, editorials, case-reports, or opinions. The clinical trials were often not controlled and were about the cephalometric evaluation after treatment with the modified Milwuakee brace, followed by the orthodontic treatment of the class II relationship with a functional appliance. Clinical trials also included the study of the associations between scoliosis and unilateral crossbite, in children with asymmetry of the upper cervical spine. This association was also investigated in rats, pigs and rabbits in clinical trials. The other associations between scoliosis and occlusion seems to be based only on cross-sectional studies, case-reports, opinions. Authors' conclusions Based

  12. A three-dimensional finite element analysis of a passive and friction fit implant abutment interface and the influence of occlusal table dimension on the stress distribution pattern on the implant and surrounding bone

    PubMed Central

    Sarfaraz, Hasan; Paulose, Anoopa; Shenoy, K. Kamalakanth; Hussain, Akhter

    2015-01-01

    Aims: The aim of the study was to evaluate the stress distribution pattern in the implant and the surrounding bone for a passive and a friction fit implant abutment interface and to analyze the influence of occlusal table dimension on the stress generated. Materials and Methods: CAD models of two different types of implant abutment connections, the passive fit or the slip-fit represented by the Nobel Replace Tri-lobe connection and the friction fit or active fit represented by the Nobel active conical connection were made. The stress distribution pattern was studied at different occlusal dimension. Six models were constructed in PRO-ENGINEER 05 of the two implant abutment connection for three different occlusal dimensions each. The implant and abutment complex was placed in cortical and cancellous bone modeled using a computed tomography scan. This complex was subjected to a force of 100 N in the axial and oblique direction. The amount of stress and the pattern of stress generated were recorded on a color scale using ANSYS 13 software. Results: The results showed that overall maximum Von Misses stress on the bone is significantly less for friction fit than the passive fit in any loading conditions stresses on the implant were significantly higher for the friction fit than the passive fit. The narrow occlusal table models generated the least amount of stress on the implant abutment interface. Conclusion: It can thus be concluded that the conical connection distributes more stress to the implant body and dissipates less stress to the surrounding bone. A narrow occlusal table considerably reduces the occlusal overload. PMID:26929518

  13. Endovascular recanalization of infrapopliteal occlusions in patients with critical limb ischemia

    PubMed Central

    Singh, Gagan D.; Armstrong, Ehrin J.; Yeo, Khung-Keong; Singh, Satinder; Westin, Gregory G.; Pevec, William C.; Dawson, David L.; Laird, John R.

    2014-01-01

    Background Endovascular therapies are increasingly used for treatment of critical limb ischemia (CLI). Infrapopliteal (IP) occlusions are common in CLI, and successful limb salvage may require restoration of arterial flow in the distribution of a chronically occluded vessel. We sought to describe the procedural characteristics and outcomes of patients with IP occlusions who underwent endovascular intervention for treatment of CLI. Methods All patients with IP interventions for treatment of CLI from 2006 to 2012 were included. Angiographic and procedural data were compared between patients who underwent intervention for IP occlusions vs IP stenosis. Restenosis was determined by Doppler ultrasound imaging. Limb salvage was the primary end point of the study. Additional end points included primary patency, primary assisted patency, secondary patency, occlusion crossing success, procedural success, and amputation-free survival. Results A total of 187 patients with CLI underwent interventions for 356 IP lesions, and 77 patients (41%) had interventions for an IP occlusion. Patients with an intervention for IP occlusion were more likely to have zero to one vessel runoff (83% vs 56%; P < .001) compared with interventions for stenosis. Compared with IP stenoses, IP occlusions were longer (118 ± 86 vs 73 ± 67 mm; P < .001) and had a smaller vessel diameter (2.5 ± 0.8 vs 2.7 ± 0.5 mm; P =.02). Wire crossing was achieved in 83% of IP occlusions, and the overall procedural success for IP occlusions was 79%. The overall 1-year limb salvage rate was 84%. Limb salvage was highest in the stenosis group, slightly lower in the successful occlusion group, and lowest in the failed occlusion group (92% vs 75% vs 58%, respectively; P = .02). Unsuccessfully treated IP occlusions were associated with a significantly higher likelihood of major amputation (hazard ratio, 5.79; 95% confidence interval, 1.89–17.7) and major amputation or death (hazard ratio, 2.69; 95% confidence interval

  14. Measurement of mandibular movements in parafunctional patient using occlusal splint with Bragg gratings: pilot study

    NASA Astrophysics Data System (ADS)

    Franco, Ana Paula G. O.; Gebert, Andréa. O.; Souza, Mauren A.; Jeranoski, Lorena; Kalinowski, Hypolito J.; Abe, Ilda

    2016-05-01

    The aim of the study is to demonstrate the potential of the fibre Braggs grating (FBG) in the measurement of different jaw movements that are performed for patients with occlusal parafunction using occlusal splints. Two silicon plates each 2mm are used, the fibre optic sensor is positioned in the maxillary left first molar region above the point of contact with opposing tooth after pressing the first plate on the model. Then the second silicon plate is pressed. The device has a final thickness of 2 mm. The occlusal splint is installed in the mouth of the patient who underwent different movements on occlusal splint. The maximum frequency bite is monitored. The results demonstrate that the bite shows a difference between grinding and clenching movements. The curves behaviour patterns are presented in order to show these different comparisons. Therefore, it is concluded that the fibre Braggs grating consists in an efficient method for monitoring the mechanical behaviour bite of patients with occlusal splints.

  15. Variations in occlusal forces with a resilient internal implant shock absorber.

    PubMed

    Chapman, R J; Kirsch, A

    1990-01-01

    The importance of an internal shock absorber for implant prostheses has concerned many, primarily because the efficacy of a shock absorber to reduce stress has not been demonstrated in vivo. This study examined 15 subjects with unilateral distal extension single implant abutments attached to a single natural tooth abutment to assess the effect of a shock-absorbing element within the implant on occlusal force levels. Occlusal forces and bilateral occlusal similarity were examined using specially adapted research software for the T-Scan occlusal analysis system. The results indicate that there is a significant difference (P less than 0.011) between occlusal forces using an internal shock absorber (18 N) and a titanium internal element (30 N).

  16. Therapeutic response of benzodiazepine, orphenadrine citrate and occlusal splint association in TMD pain.

    PubMed

    Rizzatti-Barbosa, Célia M; Martinelli, Denise A; Ambrosano, Gláucia M B; de Albergaria-Barbosa, José R

    2003-04-01

    Loss of function, muscle inflammation, and pain are some of the signs and symptoms of temporomandibular dysfunction (TMD). Pharmacological strategies to minimize the clinical manifestation of these disorders often focus on blocking or inhibiting the pain-causing symptom. Resources such as muscle-relaxants, anxiety-relief drugs, and splint therapy are often used to reduce muscular hyperactivity related to TMD muscle pain. This study compares the effect of a randomly ordered association of occlusal splint therapy (S), nonsteroid anti-inflammatory with a muscle-relaxant drug (orphenadrine citrate) (O), and an anxiety-relief drug (benzodiazepine) (B), to ease painful TMD muscle symptoms. Clinical and anamnestic analyses were recorded in accordance with the Helkimo TMD index and applied before and after treatments. Twenty-one group two Helkimo TMD adult female patients were treated, all of whom were subjected to the three random therapeutic associations proposed: SBO, BOS, and OSB. The same operator applied the three specific associations over a period of 21 days in the proposed sequence, seven days for each therapy. The results show that all the groups presented the best results in terms of relief from pain after the therapeutic association (28.5% showed a decrease and 47.6% showed an absence of symptoms). No significant difference was observed among association therapeutic protocols.

  17. Collateral circulation in ferrets (Mustela putorius) during temporary occlusion of the caudal vena cava.

    PubMed

    Calicchio, Kristina W; Bennett, R Avery; Laraio, Leonard C; Weisse, Chick; Zwingenberger, Allison L; Rosenthal, Karen L; Johnston, Matthew S; Campbell, Vicki L; Solomon, Jeffrey A

    2016-05-01

    OBJECTIVE To determine whether extent of collateral circulation would change during temporary occlusion of the caudal vena cava (CVC) in ferrets (Mustela putorius), a pressure change would occur caudal to the occlusion, and differences would exist between the sexes with respect to those changes. ANIMALS 8 adult ferrets (4 castrated males and 4 spayed females). PROCEDURES Ferrets were anesthetized. A balloon occlusion catheter was introduced through a jugular vein, passed into the CVC by use of fluoroscopy, positioned cranial to the right renal vein, and inflated for 20 minutes. Venography was performed 5 and 15 minutes after occlusion. Pressure in the CVC caudal to the occlusion was measured continuously. A CBC, plasma biochemical analysis, and urinalysis were performed immediately after the procedure and 2 or 3 days later. RESULTS All 8 ferrets survived the procedure; no differences were apparent between the sexes. Vessels providing collateral circulation were identified in all ferrets, indicating blood flow to the paravertebral venous plexus. Complications observed prior to occlusion included atrial and ventricular premature contractions. Complications after occlusion included bradycardia, seizures, and extravasation of contrast medium. Mean baseline CVC pressure was 5.4 cm H2O. During occlusion, 6 ferrets had a moderate increase in CVC pressure (mean, 24.3 cm H2O) and 2 ferrets had a marked increase in CVC pressure to > 55.0 cm H2O. CONCLUSIONS AND CLINICAL RELEVANCE Caval occlusion for 20 minutes was performed in healthy ferrets with minimal adverse effects noted within the follow-up period and no apparent differences between sexes. The CVC pressure during occlusion may be prognostic in ferrets undergoing surgical ligation of the CVC, which commonly occurs during adrenal tumor resection.

  18. Initial clinical experience of CrossBoss catheter for in-stent chronic total occlusion lesions

    PubMed Central

    Zhao, Lei; Li, Long-Bo; Wang, Zhi-Hui; Shi, Yong-Feng; Wu, Jun-Duo; Zhang, Ji-Chang; Liu, Bin

    2016-01-01

    Abstract Background: The CrossBoss coronary chronic total occlusion (CTO) crossing catheter has been demonstrated to have greatly improved the success rate of crossing CTO lesions, but there are no published data on its application for in-stent CTO lesions. Methods: In the current study, we retrospectively reviewed the clinical data of 8 patients with in-stent CTO lesions that were managed with the CrossBoss catheter and herein we report the efficacy and safety of the CrossBoss crossing and re-entry system for this clinically challenging condition. Results: The CrossBoss catheter was used for 8 patients with in-stent CTO lesions, which resulted in success in 6 cases and failure in 2 cases, with a 75% success rate. Of the 6 patients with successful treatment, 5 cases had the occlusive lesions crossed with the CrossBoss catheter through a proximal lumen-to-distal lumen approach, whereas the remaining case had his occlusive lesions penetrated by the CrossBoss catheter and the guidewire. Two cases failed in treatment as the CrossBoss catheter could not cross the occlusive lesions. The 6 cases with successful treatment included 3 cases with occlusive lesions in the left anterior descending artery, 1 case with occlusive lesions in the obtuse marginal branches, and 2 cases with occlusive lesions in the right coronary artery, and the 2 cases with failure in treatment had their occlusive lesions in the right coronary artery. In addition, patients with a higher Japan chronic total occlusion score were found to have a lower success rate of crossing the occlusive lesions. None of the patients developed complications. Conclusion: Our study demonstrates that the CrossBoss catheter has a high success rate and is safe for in-stent CTOs and can be recommended for this rather clinically challenging condition. PMID:27749568

  19. Defibrotide in the treatment of hepatic veno-occlusive disease

    PubMed Central

    Fulgenzi, Alessandro; Ferrero, Maria Elena

    2016-01-01

    Hepatic veno-occlusive disease (VOD), also known as sinusoidal obstruction syndrome (SOS), represents the most frequent complication in patients in early phase following hematopoietic stem-cell transplantation (HSCT). In its severe form, VOD/SOS can be associated with multiorgan failure and with a mortality rate >80% by day +100. Defibrotide (DF) (a mixture of 90% single-stranded phosphodiester oligonucleotides and 10% double-stranded phosphodiester oligonucleotides derived from controlled depolarization of porcine intestinal mucosal DNA) has been proposed for the treatment of SOS due to its ability to restore thrombo-fibrinolytic balance and protect endothelial cells. The present review highlights why the mechanisms of action of DF allow its successful use in the prevention and treatment of SOS following HSCT. PMID:27843363

  20. Robust object recognition under partial occlusions using NMF.

    PubMed

    Soukup, Daniel; Bajla, Ivan

    2008-01-01

    In recent years, nonnegative matrix factorization (NMF) methods of a reduced image data representation attracted the attention of computer vision community. These methods are considered as a convenient part-based representation of image data for recognition tasks with occluded objects. A novel modification in NMF recognition tasks is proposed which utilizes the matrix sparseness control introduced by Hoyer. We have analyzed the influence of sparseness on recognition rates (RRs) for various dimensions of subspaces generated for two image databases, ORL face database, and USPS handwritten digit database. We have studied the behavior of four types of distances between a projected unknown image object and feature vectors in NMF subspaces generated for training data. One of these metrics also is a novelty we proposed. In the recognition phase, partial occlusions in the test images have been modeled by putting two randomly large, randomly positioned black rectangles into each test image.