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Sample records for applied occlusal load

  1. Immediate occlusal loading for fixed prostheses in implant dentistry.

    PubMed

    Misch, Carl E; Wang, Hom-Lay

    2003-08-01

    The majority of clinical reports reveal similar survival rates between immediate-loaded and 2-stage-unloaded healing approaches in the completely edentulous patient. In our prospective study, 31 arches received immediate-loaded restorations in 30 patients, supported by 244 implants. All implants were followed a minimum of 2 years after prosthesis delivery to as long as 6 years. The implant and final prosthesis survival were 100% during this time frame. Nonetheless, these findings do not imply a submerged surgical approach is no longer necessary or prudent in many cases. Future studies may find indications based upon surgical, host, implant, and occlusal-related conditions more beneficial for one versus the other. The strength of bone and the modulus of elasticity are both directly related to bone density. The softest bone type may be 10 times weaker than the most dense types. The microstrain mismatch of titanium and the softest bone is much greater than with the densest bone. As a consequence, higher implant failure and greater crestal bone loss seem likely but as yet has not been reported in the literature. A biomechanical treatment approach to increase surface area and decrease forces applied to the immediate restorations is logical to increase implant survival. Conditions that decrease strain to a developing interface include increasing implant number, implant size, and implant thread number and depth. Patient factors such as parafunction may increase forces to the implant interface, while implant position may be used to decrease forces, especially when a splinted arch form is created. Tables 3 and 4 list guidelines for immediate occlusal loading. As a general principle, the clinical should be able to increase surface area while minimizing occlusal force to ensure long-term success. PMID:14515575

  2. The effect of occlusal restoration and loading on the development of abfraction lesions: A finite element study

    PubMed Central

    Vasudeva, Gaurav; Bogra, Poonam

    2008-01-01

    Background: Abfraction, a type of non-carious cervical tooth loss, is a poorly understood condition. One factor thought to contribute to the development of these lesions is the effect of occlusal loading and the presence of occlusal restoration. Aim and Objectives: The aim of this paper is to study the stress profile in the cervical region of mandibular first premolar with variation of occlusal loads, and to compare the stress profile between sound and occlusally restored tooth under variation of occlusal load, using two-dimensional plane strain finite element model. Materials and Methods: A mandibular first premolar was sectioned and modeled in the finite element software, along with its peridontium. Varying occlusal loads were applied along the cuspal inclines, with and without an occlusal restoration. The software used was NISA II EMRC. Result: It was found that higher occlusal loads caused more cuspal flexure and that the maximum shear stress was much higher and closer to the cervical area. It was also observed that there was a slight increase in shear stress when occlusal restoration was present. Conclusion: It was suggested that high occlusal loading and the presence of an occlusal amalgam restoration increased the stress concentration at the cervical area, which may lead to the breakdown of enamel at the cervical region. PMID:20142898

  3. Effect of the parafunctional occlusal loading and crown height on stress distribution.

    PubMed

    Torcato, Leonardo Bueno; Pellizzer, Eduardo Piza; Verri, Fellippo Ramos; Falcón-Antenucci, Rosse Mary; Batista, Victor Eduardo de Souza; Lopes, Leonardo Ferreira de Toledo Piza

    2014-01-01

    The aim of this study was to assess, by the three-dimensional finite element method, the influence of crown-to-implant ratio and parafunctional occlusal loading on stress distribution in single external hexagon implant-supported prosthesis. Computer-aided design software was used to confection three models. Each model was composed of a block bone and an external hexagon implant (5x10.0 mm) with screw-retained implant prostheses, varying the height crown: 10, 12.5 and 15 mm. Finite element analysis software was used to generate the finite element mesh and to establish the loading and boundary conditions. Normal (200 N axial and 100 N oblique load) and parafunctional forces (1,000 N axial and 500 N oblique load) were applied. The results were visualized by von Mises and maximum principal stress. In comparison with the normal occlusal force, the parafunctional occlusal force induced an increase in stress concentration and magnitude on implant (platform and first threads) and screw (neck). The cortical bone showed the highest tensile stress under parafunctional force (oblique load). The stress concentration increased as the crown height increased. It was concluded that: increasing the C/I increased stress concentration in both implant components and cortical bone; parafunctional loading increased between 4-5 times the value of stresses in bone tissue compared with functional loading; the type of loading variation factor is more influential than the crown-to-implant factor. PMID:25590205

  4. Impact of excessive occlusal load on successfully-osseointegrated dental implants: a literature review.

    PubMed

    Chang, Michael; Chronopoulos, Vasileios; Mattheos, Nikos

    2013-08-01

    The aim of the present study was to review the available evidence on the response of the peri-implant bone when subjected to excessive occlusal forces. The search strategy included papers published in English in the Medline database and the Wiley Online Library from January 1991 to December 2011. Experimental or review papers reporting the conditions of the peri-implant bone of dental implants submitted to excessive occlusal loading in the presence of a controlled oral hygiene regime were eligible for inclusion. The knowledge regarding the response of the peri-implant bone when the dental implant is excessively loaded is limited, and the level of evidence is poor. With animal experimental studies showing conflicting results, it is unclear whether occlusal overload might cause marginal bone loss or total loss of osseointegration to already osseointegrated dental implants when the applied load exceeds the biologically-acceptable limit. This biological limit is also unknown. Furthermore, higher remodeling activity of the peri-implant bone is found around implants subjected to high loading forces. PMID:23918506

  5. 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

  6. 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. PMID:18783775

  7. 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).

  8. Occlusal stability.

    PubMed

    Wiens, Jonathan P; Priebe, Jennifer W

    2014-01-01

    Occlusion is the foundation for clinical success in fixed, removable, and implant prosthodontic treatment. Understanding those principles is critical when restoring a patient's occlusion. Many philosophies, devices, and theories of occlusion have evolved based on anecdotal clinical observations and applied geometric perceptions. The literature has reported these classic and contemporary occlusal concepts. As evidence-based dentistry emerged, it championed scrutiny of previously held beliefs, resulting in the abandonment of many pragmatic, yet beneficial occlusal procedures. The impetus toward scientific discovery, whereby factual information might be universally applied in dental education and clinical practice, has renewed interest in occlusal studies. PMID:24286644

  9. Investigating and Analyzing Applied Loads Higher Than Limit Loads

    NASA Technical Reports Server (NTRS)

    Karkehabadi, R.; Rhew, R. D.

    2004-01-01

    The results of the analysis for Balance 1621 indicate that the stresses are high near sharp corners. It is important to increase the size of the fillets to relieve some of the high stresses for the balances that will be designed. For the existing balances, the stresses are high and do not satisfy the established criteria. Two options are considered here. One is a possible modification of the existing balances, and two is to consider other load options. Redesigning a balance can be done in order to enhance the structural integrity of the balance. Because an existing balance needs to be modified, it is not possible to increase the fillet sizes without some further modifications to the balance. It is required that some materials be extracted from the balance in order to have larger fillet sizes. Researchers are interested in being able to apply some components of the load on the balance above the limit loads assigned. Is it possible to enhance the load on the same balance and maintain the factor of safety required? Some loads were increased above their limit loads and analyzed here.

  10. Finite Element Analysis of Bone Stress for Miniscrew Implant Proximal to Root Under Occlusal Force and Implant Loading.

    PubMed

    Shan, Li-Hua; Guo, Na; Zhou, Guan-jun; Qie, Hui; Li, Chen-Xi; Lu, Lin

    2015-10-01

    Because of the narrow interradicular spaces and varying oral anatomies of individual patients, there is a very high risk of root proximity during the mini implants inserting. The authors hypothesized that normal occlusal loading and implant loading affected the stability of miniscrew implants placed in proximity or contact with the adjacent root. The authors implemented finite element analysis (FEA) to examine the effectiveness of root proximity and root contact. Stress distribution in the bone was assessed at different degrees of root proximity by generating 4 finite element models: the implant touches the root surface, the implant was embedded in the periodontal membrane, the implant touches the periodontal surface, and the implant touches nothing. Finite element analysis was then carried out with simulations of 2 loading conditions for each model: condition A, involving only tooth loading and condition B, involving both tooth and implant loading. Under loading condition A, the maximum stress on the bone for the implant touching the root was the distinctly higher than that for the other models. For loading condition B, peak stress areas for the implant touching the root were the area around the neck of the mini implant and the point of the mini implant touches the root. The results of this study suggest that normal occlusal loading and implant loading contribute to the instability of the mini implant when the mini implant touches the root. PMID:26207429

  11. 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. PMID:25458179

  12. Photoelastic and Finite Element Analyses of Occlusal Loads in Mandibular Body

    PubMed Central

    Freire, Alexandre Rodrigues; Prado, Felippe Bevilacqua; Asprino, Luciana; Correr-Sobrinho, Lourenço; Caria, Paulo Henrique Ferreira

    2014-01-01

    This study proposed to evaluate the mandibular biomechanics in the posterior dentition based on experimental and computational analyses. The analyses were performed on a model of human mandible, which was modeled by epoxy resin for photoelastic analysis and by computer-aided design for finite element analysis. To standardize the evaluation, specific areas were determined at the lateral surface of mandibular body. The photoelastic analysis was configured through a vertical load on the first upper molar and fixed support at the ramus of mandible. The same configuration was used in the computer simulation. Force magnitudes of 50, 100, 150, and 200 N were applied to evaluate the bone stress. The stress results presented similar distribution in both analyses, with the more intense stress being at retromolar area and oblique line and alveolar process at molar level. This study presented the similarity of results in the experimental and computational analyses and, thus, showed the high importance of morphology biomechanical characterization at posterior dentition. PMID:25374695

  13. 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.

  14. 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

  15. A comparison of atmospheric loading models applied to SLR data

    NASA Astrophysics Data System (ADS)

    Koenig, Rolf; Dill, Robert; Raimondo, Jean-Claude; Vei, Margarita

    2016-04-01

    We compute displacements of global SLR station coordinates by atmospheric loading based on surface pressure data from European Centre for Medium-Range Weather Forecasts (ECMWF) ERA-interim data. Inhouse we generate two branches: firstly straightforward following Farrel's theory but using updated load Love numbers, secondly from utilizing localized Green's functions instead of global ones. Externally provided displacements are available f.i. from the International Mass Loading Service (IMLS) based on different input data and modeling. We compare these displacements and apply them to Satellite Laser Ranging (SLR) data processing of a recent six years period of the LAGEOS, LARES, AJISAI, STARLETTE and STELLA geodetic missions. We assess the impact of the loading models on precise orbit determination and Earth parameters of interest.

  16. Local structural excitations in model glass systems under applied load

    NASA Astrophysics Data System (ADS)

    Swayamjyoti, S.; Löffler, J. F.; Derlet, P. M.

    2016-04-01

    The potential-energy landscape of a model binary Lennard-Jones structural glass is investigated as a function of applied external strain, in terms of how local structural excitations (LSEs) respond to the load. Using the activation relaxation technique and nudged elastic band methods, the evolving structure and barrier energy of such LSEs are studied in detail. For the case of a tensile/compressive strain, the LSE barrier energies generally decrease/increase, whereas under pure shear, it may either increase or decrease resulting in a broadening of the barrier energy distribution. It is found that how a particular LSE responds to an applied strain is strongly controlled by the LSE's far-field internal stress signature prior to loading.

  17. 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. PMID:21070431

  18. Evidence-based considerations for removable prosthodontic and dental implant occlusion: a literature review.

    PubMed

    Taylor, Thomas D; Wiens, Jonathan; Carr, Alan

    2005-12-01

    The dental literature is filled with discussions of dental occlusion, occlusal schemes, philosophies, and methods to correct and restore the diseased, worn, or damaged occlusion. Traditionally, these discussions have been empirical in nature and not based on scientific evidence. Due to the empirical nature of the literature, the study of occlusion has been extremely complex and troublesome to both pre- and post-doctoral students. The introduction of osseointegrated implants has further complicated the situation. Dentists may apply the principles of occlusion for the natural dentition directly to implant-supported and retained restorations. Although this may be successful, this rationale may result in overly complex or simplified treatment protocols and outcomes. There is an emerging body of scientific literature related to dental implant therapy that may be useful in formulating treatment protocols and prosthesis designs for implant-supported restorations. This review focuses on some of the "classic" removable prosthodontic literature and the currently available scientific literature involving removable prosthodontic occlusion and dental implant occlusion. The authors reviewed the English peer-reviewed literature prior to 1996 in as comprehensive manner as possible, and material after 1996 was reviewed electronically using MEDLINE. Electronic searches of the literature were performed in MEDLINE using key words-animal studies, case series, clinical trials, cohort studies, complete denture occlusion, dental implant function, dental implant occlusion, dental implant occlusion research, dental implant functional loading, dental implants, dental occlusion, dental occlusion research, denture function, denture occlusion, dentures, implant function, implant functional loading, implant occlusion, occlusion, and removable partial denture occlusion-in various combinations to obtain potential references for review. A total of 5447 English language titles were obtained, many of

  19. 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. PMID:27100809

  20. 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.

  1. 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

  2. Effect of material properties of composite restoration on the strength of the restoration-dentine interface due to polymerization shrinkage, thermal and occlusal loading.

    PubMed

    Borkowski, Krzysztof; Kotousov, Andrei; Kahler, Bill

    2007-07-01

    The purpose of this investigation was to adopt an analytical approach to analyse stresses at the restoration-dentine interface caused by polymerization shrinkage, occlusal and thermal loading with the primary focus on evaluating the effect of the material properties of the composite restoration on the strength of the interface. Some essential simplifications were employed to derive an explicit analytical solution. The results confirm previous findings that interfacial stresses due to polymerization shrinkage are increased with the higher modulus of elasticity of the restoration, while Poisson's ratio of the restorative material has a very small influence on these stresses. Occlusal loading resulted in much lower interfacial stresses when compared to shrinkage and thermal loads. The obtained results were in a good agreement with other numerical and clinical studies. From the modelling analysis it was found that the majority of commercially available composite restorative materials are expected to create significant interfacial stresses when subjected to cold temperatures. In addition, it was shown that there is a considerable potential for interfacial stresses to be minimised by an appropriate selection of thermo-mechanical properties of the restorative material especially with the new finding on the negative temperature variation effect. PMID:17000129

  3. Efficacy and safety of Pro Re Nata regimen without loading dose ranibizumab injections in retinal vein occlusion

    PubMed Central

    Unsal, Erkan; Eltutar, Kadir; Sultan, Pınar; Gungel, Hulya

    2015-01-01

    Objectives: To evaluate the effects and safety of intravitreal ranibizumab on visual acuity and anatomic results in the treatment of macular edema due to retinal vein occlusion (RVO). Methods: Forty Six eyes of 45 patients who were administered intravitreal ranibizumab because of macular edema due to Retinal Vein Occlusion (RVO) were included in this retrospective clinical study. During monthly follow-up, the best corrected visual acuity values in terms of LogMAR with The Early Treatment Diabetic Retinopathy Study (ETDRS) chart, central macular thickness (CMT), and complications were examined. Cases were classified as central retinal vein occlusion (CRVO), superotemporal branch retinal vein occlusion (BRVO), and inferotemporal BRVO. We only included RVO patients but using ETDRS chart for the vision measurement. Results: In all follow-up months, there was a significant increase in BCVA in all RVO cases and in superotemporal BRVO cases after the first injection of ranibizumab. Although there was no significant increase in the 1st month of follow-up period compared to pre-treatment, there was significant increase in 2-6 months in inferotemporal BRVO patients. There was no statistically significant increase in 1st and 2nd month follow-up periods compared to pre-treatment; however there was a significant increase in 3-6 months in the CRVO patients. There was a significant decrease in average CMT measurements in all follow-up months compared to pre-treatment in all RVO cases, in superotemporal and inferotemporal BRVO cases. There was no significant decrease in average CMT measurements in the 1st, 2nd, and 3rd months compared to pre-treatment although there was a significant decrease in 4-6 months in cases included in the CRVO patients. Conclusions: Intraocular ranibizumab injections provided rapid, effective treatment for macular edema due to RVO with low rates of ocular and nonocular safety events. However, repeated injections and frequent follow-up intervals may be

  4. 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.

  5. Applying a Stiffened Stitched Concept to Shear-Loaded Structure

    NASA Technical Reports Server (NTRS)

    Jegley, Dawn C.

    2014-01-01

    NASA and The Boeing Company have worked to develop new low-cost, lightweight composite structures for aircraft. A stitched carbon-epoxy material system was developed to reduce the weight and cost of transport aircraft structure, first in the NASA Advanced Composites Technology (ACT) Program in the 1990's and now in the Environmentally Responsible Aviation (ERA) Project. By stitching through the thickness of a dry carbon fiber material prior to cure, the need for mechanical fasteners is almost eliminated. Stitching also provides the benefit of reducing or eliminating delaminations, including those between stiffener flanges and skin. The stitched panel concept used in the ACT program used simple blade-stiffeners as stringers, caps, and clips. Today, the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) concept is being developed for application to advanced vehicle configurations. PRSEUS provides additional weight savings through the use of a stiffener with a thin web and a unidirectional carbon rod at the top of the web which provides structurally efficient stiffening. Comparisons between stitched and unstitched structure and between blade-stiffened and rod-stiffened structure are presented focusing on a panel loaded in shear. Shear loading is representative of spar loading in wing structures.

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

    PubMed Central

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

    2011-01-01

    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 (M1). The antagonistic crowns M1 and P2–M1 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 M1 and P2–M1 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 M1 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. PMID:21615398

  7. 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.

  8. Trunk kinematics and trunk muscle activity during a rapidly applied load.

    PubMed

    Thomas, J S; Lavender, S A; Corcos, D M; Andersson, G B

    1998-08-01

    This study investigated the trunk kinematics and electromyographic (EMG) activity of eight trunk muscles when "expected" and "unexpected" loads were applied directly to the torso. Twenty individuals (mean age: 25.1 yr; range 20-33 yr) participated in this mixed model study in which gender was the between-subjects factor, and expectancy and symmetry of the applied load were within-subject factors. The sudden load was delivered to the subject via a cable attached to a thoracic harness and motion was restricted to the lumbar spine by strapping the pelvis to a rigid fixation apparatus. Surface EMG was recorded bilaterally from the longissimus thoracis (LGT), erector spinae (ERS), rectus abdominis (RAB) and the external obliques (EXO). Trunk kinematics were measured with a Lumbar Motion Monitor. During expected loading conditions, the peak muscle activity was reduced for the RAB and EXO bilaterally, and for the ERS(R) (p < 0.01) relative to the unexpected conditions. Conversely, the normalized area of EMG activity prior to the onset of load was increased for the ERS and EXO bilaterally, and for the RAB(R) (p < 0.05) during an expected loading event. Trunk motion in the sagittal and frontal planes was reduced during expected loading. Activation of the trunk muscles just prior to a rapid loading event increases trunk stiffness, decreasing trunk displacement and peak muscle activity. PMID:9779395

  9. 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.

  10. 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.

  11. Tensile-strength apparatus applies high strain-rate loading with minimum shock

    NASA Technical Reports Server (NTRS)

    Cotrill, H. E., Jr.; Mac Glashan, W. F., Jr.

    1966-01-01

    Tensile-strength testing apparatus employs a capillary bundle through which a noncompressible fluid is extruded and a quick-release valve system. This apparatus applies the test loads at relatively constant very high strain rates with minimal shock and vibration to the tensile specimen and apparatus.

  12. 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. PMID:26159057

  13. Finite element nonlinear random response of beams to acoustic and thermal loads applied simultaneously

    NASA Astrophysics Data System (ADS)

    Chen, Ruixi; Mei, Chuh

    1993-04-01

    A finite element formulation combined with the equivalent linearization technique and the normal mode method is developed for the study of nonlinear random response of beams subjected to simultaneously applied acoustic and thermal loads. Examples include thermally buckled random response of simply supported beam, clamped-clamped beam and simply supported-clamped beam. To compare and validate the present formulation, results are compared with the solutions from existing sequential load method, and significant difference has been found. Results by classical continuum solution and the solution of Fokker-Planck-Kolmogorov equation are also derived and obtained for comparison.

  14. 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.

  15. 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.

  16. Load-induced debonding of FRP composites applied to reinforced concrete

    NASA Astrophysics Data System (ADS)

    Blok, Joel; Brown, Jeff

    2009-05-01

    Fiber-reinforced polymer (FRP) composites are widely used to increase the flexural and shear capacity of reinforced concrete (RC) elements. One potential disadvantage is that strengthened surfaces are no longer visible and cracks or delaminations that result from excessive loading or fatigue may go undetected. This research investigated thermal imaging techniques for monitoring and evaluating load-induced delamination of FRP composites applied to small scale RC beams. Two beams (3.5 in x 4.5 in x 58 in) were loaded monotonically to failure. Infrared thermography (IRT) inspections were performed at various load levels through failure using a composite phase imaging technique. Two similar beams were tested in fatigue and periodic IRT inspections were performed at 50,000-cycle intervals. Individual phase values for each pixel were designated as "well-bonded", "suspect" or "unbonded" to indicate the quality of FRP bond. Suspect areas included regions of excess thickened-epoxy tack-coat and smaller installation defects in the unloaded specimens. The long-term objective of this research is to develop a practical framework for conducting quantitative IRT inspections of FRP composites applied to RC and incorporating these results into acceptance criteria for new installations and predictions for the remaining service life of in-service FRP systems. This method may also offer insight into the necessity for repairs to in-service systems.

  17. 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.

  18. A power and load priority control concept as applied to a Brayton cycle turbo-electric generator.

    NASA Technical Reports Server (NTRS)

    Kelsey, E. L.; Young, R. N.

    1972-01-01

    This paper describes a system to regulate the speed and power output of a Brayton Cycle Power System under varying load. A typical user load profile is applied and a simple load priority and parasitic load is used for system regulation. Power storage is provided by batteries with charge and discharge converters to demonstrate support capability. The breadboard system is tested with the Brayton Cycle Demonstrator at the National Aeronautics and Space Administration, Manned Space Craft Center, Houston, Texas.

  19. 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.

  20. Branch retinal vein occlusion.

    PubMed

    Hamid, Sadaf; Mirza, Sajid Ali; Shokh, Ishrat

    2008-01-01

    Retinal vein occlusions (RVO) are the second commonest sight threatening vascular disorder. Branch retinal vein occlusion (BRVO) and central retinal vein occlusion (CRVO) are the two basic types of vein occlusion. Branch retinal vein occlusion is three times more common than central retinal vein occlusion and- second only to diabetic retinopathy as the most common retinal vascular cause of visual loss. The origin of branch retinal vein occlusion undoubtedly includes both systemic factors such as hypertension and local anatomic factors such as arteriovenous crossings. Branch retinal vein occlusion causes a painless decrease in vision, resulting in misty or distorted vision. Current treatment options don't address the underlying aetiology of branch retinal vein occlusion. Instead they focus on treating sequelae of the occluded venous branch, such as macular oedema, vitreous haemorrhage and traction retinal detachment from neovascularization. Evidences suggest that the pathogenesis of various types of retinal vein occlusion, like many other ocular vascular occlusive disorders, is a multifactorial process and there is no single magic bullet that causes retinal vein occlusion. A comprehensive management of patients with retinal vascular occlusions is necessary to correct associated diseases or predisposing abnormalities that could lead to local recurrences or systemic event. Along with a review of the literature, a practical approach for the management of retinal vascular occlusions is required, which requires collaboration between the ophthalmologist and other physicians: general practitioner, cardiologist, internist etc. as appropriate according to each case. PMID:19385476

  1. 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.

  2. Applying local Green's functions to study the influence of the crustal structure on hydrological loading displacements

    NASA Astrophysics Data System (ADS)

    Dill, Robert; Klemann, Volker

    2015-04-01

    The influence of the elastic Earth properties on seasonal or shorter periodic surface mass loads due to atmospheric surface pressure and terrestrial water storage variations is usually modeled by applying a local isostatic model like a homogeneous half-space model, or by a one dimensional spherical Earth model like PREM from which a unique set of elastic load Love numbers, or alternatively, elastic Green's functions are derived. The drawbacks of these strategies are that, in the first case, the response according to the local Earth structure is valid only if load and observer almost coincide, or that, in the second case, only the response of an average Earth structure is considered. However, for surface loads with horizontal scales less than 2500 km2, as for instance, for strong localized hydrological signals associated with heavy precipitation events and river floods, the Earth elastic response becomes very sensitive to inhomogeneities in the Earth crustal structure. We derive a set of local Green's functions defined for every global 1°× 1° gridcell for the 3-layer crustal structure TEA12. Local Green's functions show standard deviations of ±12% in the vertical and ±21% in the horizontal directions for distances in the range from 0.1° to 0.5°. The application of local Green's functions introduces a variability of 0.5 - 1.0 mm into the hydrological loading displacements, both in vertical and in horizontal directions. Maximum changes due to the local crustal structures are from -25% to +26% in the vertical and -91% to +55% in the horizontal displacements. In addition, the horizontal displacement changes its direction significantly, even to the opposite. The modeling of a site-dependent crustal response to surface loads provides an alternative way to probe the density and elastic structure of the Earth's crust and mantle by means of observed surface deformations caused by mass re-distributions. In addition, realistic loading models allow the monitoring of mass

  3. 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

  4. Data driven models applied in building load forecasting for residential and commercial buildings

    NASA Astrophysics Data System (ADS)

    Rahman, SM Mahbobur

    A significant portion of the operating costs of utilities comes from energy production. Machine learning methods are widely used for short-term load forecasts for commercial buildings and also the utility grid. These forecasts are used to minimize unit power production costs for the energy managers for better planning of power units and load management. In this work, three different state-of-art machine learning methods i.e. Artificial Neural Network, Support Vector Regression and Gaussian Process Regression are applied in hour ahead and 24 --hour ahead building energy forecasting. The work uses four residential buildings and one commercial building located in Downtown, San Antonio as test-bed using energy consumption data from those buildings monitored in real-time. Uncertainty quantification analysis is conducted to understand the confidence in each forecast using Bayesian Network. Using a combination of weather variables and historical load, forecasting is done in a supervised way based on a moving window training algorithm. A range of comparisons between different forecasting models in terms of relative accuracy are then presented.

  5. Acute arterial occlusion - kidney

    MedlinePlus

    ... arterial thrombosis; Renal artery embolism; Acute renal artery occlusion; Embolism - renal artery ... often result in permanent kidney failure. Acute arterial occlusion of the renal artery can occur after injury ...

  6. Effect of Preparation Taper, Height and Marginal Design Under Varying Occlusal Loading Conditions on Cement Lute Stress: A Three Dimensional Finite Element Analysis.

    PubMed

    Tripathi, Siddhi; Amarnath, Gowdagere Shamanna; Muddugangadhar, Byrasandra Channapa; Sharma, Ashish; Choudhary, Suchismita

    2014-12-01

    To assess the effect of preparation taper, height and margin design under different loading conditions on cement lute stress. A 3-D FE model of an upper second premolar and molar was developed from CT scan of human skull using software programmes (MIMICS, Hypermesh and ANSYS). 10° and 30° taper, 3 and 5 mm preparation height and shoulder and chamfer finish lines were used. Type 1 Glass ionomer cement with 24 μm lute width was taken and the model was loaded under 100 N horizontal point load, vertical point load distributed axial load. The maximum shear stress and Von Mises stress within the cement lute were recorded. The maximum shear stresses ranged from 1.70 to 3.93 MPa (horizontal point loading), 0.66 to 3.04 MPa (vertical point loading), 0.38 to 0.87 MPa (distributed loading). The maximum Von Mises stresses ranged from 3.39 to 10.62 MPa (horizontal point loading), 1.93 to 8.58 MPa (vertical point loading) and 1.49 to 3.57 MPa (distributed loading). The combination of 10° taper and 5 mm height had the lowest stress field while the combination of 30° taper and 5 mm height had the highest stress field. Distributed axial loading shows least stress, better stress homogenization and gives a favorable prognosis for the fixed prostheses. Smaller preparation taper of 10° is biomechanically more acceptable than a 30° taper. It is desirable to decrease taper as height increases. The chamfer margin design is associated with greater local cement stresses toward the margins that could place the cement at greater risk for microfracture and failure. PMID:26199500

  7. Sliding Wear Response of a Bronze Bushing: Influence of Applied Load and Test Environment

    NASA Astrophysics Data System (ADS)

    Prasad, B. K.

    2012-10-01

    This investigation pertains to the examination of the sliding wear behavior of a leaded-tin bronze bushing under the conditions of varying applied loads and test environments against a steel shaft. The test environment was changed by adding 5% of solid lubricants like talc and lead to an oil lubricant separately as well as in combination; the fraction of the two (solid) lubricants within the solid lubricant mixture was varied in the range of 25-75% in the latter case. The wear performance of the bushing was characterized in terms of the wear rate, frictional heating, and friction coefficient. The increasing load led to deterioration in the wear response, while the addition of the solid lubricant particles produced a reverse effect. Further, an appreciable difference in the wear behavior was not observed when the tests were conducted in the oil plus talc and oil plus lead lubricant mixtures. However, the oil containing lead and talc together brought about a significant improvement in the wear response; best results were obtained in the case of the lubricant mixture consisting of lead and talc together in the ratio of 3:1 in the oil. The observed wear behavior of the samples has been discussed in terms of specific characteristics of various microconstituents. The features of the wear surfaces and subsurface regions further substantiated the wear response and enabled us to understand the operating material removal mechanisms.

  8. Frictionless compression testing using load-applying platens made from porous graphite aerostatic bearings

    NASA Astrophysics Data System (ADS)

    El-Aguizy, Tarek; Plante, Jean-Sebastien; Slocum, Alexander H.; Vogan, John D.

    2005-07-01

    In compression testing of soft materials at high strains, friction between a sample and the load-applying platens induces a differential lateral expansion that is visually evident as barreling. Barreling reduces the accuracy of the tests as a means of establishing accurate material properties. Current techniques for reducing friction, which involve liquid squeeze film lubrication, may not achieve true frictionless interfaces, are messy, and may adversely affect some samples. This article examines the use of porous graphite aerostatic bearings as a frictionless testing interface. The physics of a soft material under compressive loading by porous air bearings is investigated with simple finite element analysis and air flow models. An aerostatic bearing assembly is also constructed and compared to other friction reduction techniques. The results of these experiments indicate that there are benefits to using air bearings as they are clean, chemically inert, extremely stiff, reduce friction to levels comparable to existing methods, have negligible squeeze film effect, are repeatable, and allow for cyclic compression testing.

  9. A michigan-type occlusal splint with spring-loaded mandibular protrusion functionality for treatment of anterior disk dislocation with reduction.

    PubMed

    Proff, Peter; Richter, Ernst-Jürgen; Blens, Torsten; Fanghänel, Jochen; Hützen, Daniel; Kordass, Bernd; Gedrange, Tomas; Rottner, Kurt

    2007-01-01

    For treatment of temporomandibular disorders Michigan-type splints are frequently used, as are mandibular advancement appliances for patients diagnosed with anterior disk dislocation. As both types show good results, the combination of these two mechanisms into one bimaxillary appliance was tested on eight patients where splint therapy had brought reduction but not complete elimination of the symptoms. An existing maxillary Michigan splint was modified so that advancement springs could be fitted and the generated forces were transmitted to a mandibular retainer, which did not interfere with the function of the splint. Treatment progress was monitored with computerized axiography and in all cases the axiographic tracings after the bimaxillary treatment showed no pattern indicative of disk dislocation under normal jaw movements. Myofascial pain symptoms, already improved by the pre-treatment with the Michigan splint, were found to be reduced further or eliminated completely. The approach of retrofitting a Michigan splint with the springs allowed for a versatile appliance, which required no occlusal alteration to the finely adapted splint but could as easily be brought back to the simple splint-functionality either for daytime use or for a period of stabilization of the result after successful treatment. Compliance was found to be very good and the short treatment period, together with the small force levels did not produce any detectable dental side effects. PMID:17695993

  10. Follicular occlusion tetrad.

    PubMed

    Vasanth, Vani; Chandrashekar, Byalakere Shivanna

    2014-10-01

    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

  11. 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

  12. Applying cognitive load theory to the redesign of a conventional database systems course

    NASA Astrophysics Data System (ADS)

    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 structure for a database course, covering database design first, then database development. Analysis showed the conventional course content was appropriate but the instructional materials used were too complex, especially for novice students. The redesign of instructional materials applied CLT to remove split attention and redundancy effects, to provide suitable worked examples and sub-goals, and included an extensive re-sequencing of content. The approach was primarily directed towards mid- to lower performing students and results showed a significant improvement for this cohort with the exam failure rate reducing by 34% after the redesign on identical final exams. Student satisfaction also increased and feedback from subsequent study was very positive. The application of CLT to the design of instructional materials is discussed for delivery of technical courses.

  13. Biomechanical Comparison of Robotically Applied Pure Moment, Ideal Follower Load, and Novel Trunk Weight Loading Protocols on L4-L5 Cadaveric Segments during Flexion-Extension

    PubMed Central

    Bennett, Charles R.; DiAngelo, Denis J.

    2015-01-01

    Background Extremely few in-vitro biomechanical studies have incorporated shear loads leaving a gap for investigation, especially when applied in combination with compression and bending under dynamic conditions. The objective of this study was to biomechanically compare sagittal plane application of two standard protocols, pure moment (PM) and follower load (FL), with a novel trunk weight (TW) loading protocol designed to induce shear in combination with compression and dynamic bending in a neutrally potted human cadaveric L4-L5 motion segment unit (MSU) model. A secondary objective and novelty of the current study was the application of all three protocols within the same testing system serving to reduce artifacts due to testing system variability. Methods Six L4-L5 segments were tested in a Cartesian load controlled system in flexion-extension to 8Nm under PM, simulated ideal 400N FL, and vertically oriented 400N TW loading protocols. Comparison metrics used were rotational range of motion (RROM), flexibility, neutral zone (NZ) range of motion, and L4 vertebral body displacements. Results Significant differences in vertebral body translations were observed with different initial force applications but not with subsequent bending moment application. Significant reductions were observed in combined flexion-extension RROM, in flexibility during extension, and in NZ region flexibility with the TW loading protocol as compared to PM loading. Neutral zone ranges of motion were not different between all protocols. Conclusions The combined compression and shear forces applied across the spinal joint in the trunk weight protocol may have a small but significantly increased stabilizing effect on segment flexibility and kinematics during sagittal plane flexion and extension. PMID:26273551

  14. Juxtarenal aortic occlusion.

    PubMed Central

    Tapper, S S; Jenkins, J M; Edwards, W H; Mulherin, J L; Martin, R S; Edwards, W H

    1992-01-01

    The authors' experience with 113 aortic occlusions in 103 patients during a 26-year period (1965 to 1991) is reviewed. The authors found three distinct patterns of presentation: group I (n = 26) presented with acute aortic occlusion, group II (n = 66) presented with chronic aortic occlusion, and group III (n = 21) presented with complete occlusion of an aortic graft. Perioperative mortality rates were 31%, 9%, and 4.7% for each respective group and achieved statistical significance when comparing group I with group II (p = 0.009) and group I with group III (p = 0.015). Group I presented with profound metabolic insults due to acute ischemia and fared poorly. Group II presented with chronic claudication and did well long-term. Group III presented with acute ischemia but did well because of established collateral circulation. The treatment and expected outcome of aortic occlusion depends on the cause. PMID:1616381

  15. Vertebrobasilar Artery Occlusion

    PubMed Central

    Schoen, Jessica C.; Boysen, Megan M.; Warren, Chase R.; Chakravarthy, Bharath; Lotfipour, Shahram

    2011-01-01

    The presentation of vertebrobasilar artery occlusion varies with the cause of occlusion and location of ischemia. This often results in delay in diagnosis. Areas of the brain supplied by the posterior circulation are difficult to visualize and usually require angiography or magnetic resonance imaging. Intravenous thrombolysis and local-intra arterial thrombolysis are the most common treatment approaches used. Recanalization of the occluded vessel significantly improves morbidity and mortality. Here we present a review of the literature and a case of a patient with altered mental status caused by vertebrobasilar artery occlusion. PMID:21691534

  16. 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. PMID:23002705

  17. Intermittent applied mechanical loading induces subchondral bone thickening that may be intensified locally by contiguous articular cartilage lesions

    PubMed Central

    Poulet, B.; de Souza, R.; Kent, A.V.; Saxon, L.; Barker, O.; Wilson, A.; Chang, Y.-M.; Cake, M.; Pitsillides, A.A.

    2015-01-01

    Summary Objectives Changes in subchondral bone (SCB) and cross-talk with articular cartilage (AC) have been linked to osteoarthritis (OA). Using micro-computed tomography (micro-CT) this study: (1) examines changes in SCB architecture in a non-invasive loading mouse model in which focal AC lesions are induced selectively in the lateral femur, and (2) determines any modifications in the contralateral knee, linked to changes in gait, which might complicate use of this limb as an internal control. Methods Right knee joints of CBA mice were loaded: once with 2weeks of habitual use (n = 7), for 2weeks (n = 8) or for 5weeks (n = 5). Both left (contralateral) and right (loaded) knees were micro-CT scanned and the SCB and trabecular bone analysed. Gait analysis was also performed. Results These analyses showed a significant increase in SCB thickness in the lateral compartments in joints loaded for 5weeks, which was most marked in the lateral femur; the contralateral non-loaded knee also showed transient SCB thickening (loaded once and repetitively). Epiphyseal trabecular bone BV/TV and trabecular thickness were also increased in the lateral compartments after 5 weeks of loading, and in all joint compartments in the contralateral knee. Gait analysis showed that applied loading only affected gait in the contralateral himd-limb in all groups of mice from the second week after the first loading episode. Conclusions These data indicate a spatial link between SCB thickening and AC lesions following mechanical trauma, and the clear limitations associated with the use of contralateral joints as controls in such OA models, and perhaps in OA diagnosis. PMID:25655679

  18. 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. ...

  19. Retinal vein occlusion

    MedlinePlus

    ... Berrocal MH, Rodriguez FJ, et al. Pan-American Collaborative Retina Study Group (PACORES). Comparison of two doses ... retinal vein occlusion: results from the Pan-American Collaborative Retina Study Group at 6 months of follow- ...

  20. Prosthetic abutment influences bone biomechanical behavior of immediately loaded implants.

    PubMed

    Camargos, Germana de Villa; Sotto-Maior, Bruno Salles; Silva, Wander José da; Lazari, Priscilla Cardoso; Del Bel Cury, Altair Antoninha

    2016-05-31

    This study aimed to evaluate the influence of the type of prosthetic abutment associated to different implant connection on bone biomechanical behavior of immediately and delayed loaded implants. Computed tomography-based finite element models comprising a mandible with a single molar implant were created with different types of prosthetic abutment (UCLA or conical), implant connection (external hexagon, EH or internal hexagon, IH), and occlusal loading (axial or oblique), for both immediately and delayed loaded implants. Analysis of variance at 95%CI was used to evaluate the peak maximum principal stress and strain in bone after applying a 100 N occlusal load. The results showed that the type of prosthetic abutment influences bone stress/strain in only immediately loaded implants. Attachment of conical abutments to IH implants exhibited the best biomechanical behavior, with optimal distribution and dissipation of the load in peri-implant bone. PMID:27253141

  1. 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.

  2. 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

  3. 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

    2016-01-01

    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. Damage detection using data-driven methods applied to moving-load responses

    NASA Astrophysics Data System (ADS)

    Cavadas, Filipe; Smith, Ian F. C.; Figueiras, Joaquim

    2013-08-01

    Developed economies depend on complex and extensive systems of infrastructure to maintain economic prosperity and quality of life. In recent years, the implementation of Structural health monitoring (SHM) systems on full-scale bridges has increased. The goal of these systems is to inform owners of the condition of structures, thereby supporting surveillance, maintenance and other management tasks. Data-driven methods, that involve tracking changes in signals only, are well-suited for analyzing measurements during continuous monitoring of structures. Also, information provided by the response of structures under moving loads is useful for condition assessment. This paper discusses the application of data-driven methods on moving-load responses in order to detect the occurrence and the location of damage. First, an approach for using moving-load responses as time series data is proposed. The work focuses on two data-driven methods - Moving principal component analysis (MPCA) and Robust regression analysis (RRA) - that have already been successful for damage detection during continuous monitoring. The performance of each method is assessed using data obtained by simulating the crossing of a point-load on a simple frame.

  5. 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…

  6. Multi-parameter sensing with a single magnetoelastic sensor by applying loads on the null locations of multiple resonant modes

    NASA Astrophysics Data System (ADS)

    DeRouin, Andrew; Ghee Ong, Keat

    2016-03-01

    Magnetoelastic sensors are mass sensitive sensors commonly used for stress and pressure measurement, as well as chemical and biological monitoring when combined with a functionalized coating. Magnetoelastic sensors are typically made of free-standing, rectangular strips of magnetoelastic materials that exhibit longitudinal, extensional vibrations due to the excitation of magnetic fields. A single magnetoelastic sensor is generally used to monitor one parameter since only the fundamental resonant frequency is measured. Multiple-parameter sensing in close proximity has previously been achieved by using multiple magnetoelastic sensors of different dimensions and tracking their resonant frequencies independently. However, this requires a large surface area and inconvenient layout of dissimilarly shaped sensors. This paper presents a technique for monitoring multiple parameters with a single magnetoelastic sensor by applying separate mass loads at the null points (points of zero vibration) of multiple resonant modes. Applying a load at a null location does not affect the corresponding resonant mode but alters the resonant frequencies of other modes. Therefore, by isolating the variables of interest to multiple null points and simultaneously measuring the resonant frequency shifts of related resonant modes, the masses at each null location can be calculated. Results showed that changing the coverage at a null location along the width of the sensor can be used to minimize the loading effect on the corresponding resonant mode. In contrast, changing the lengthwise coverage can maximize the loading effect on other resonant modes, thus increasing the mass sensitivity of the sensor. Furthermore, simultaneously applying loads to null points of multiple resonant modes had a nearly additive effect, allowing detection of multiple parameters with a single magnetoelastic sensor.

  7. 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.

  8. 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.

  9. 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

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

    DOE PAGESBeta

    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

  11. Applying diffuse ultrasound under dynamic loading to improve closed crack characterization in concrete.

    PubMed

    Payan, C; Quiviger, A; Garnier, V; Chaix, J F; Salin, J

    2013-08-01

    Recent studies show the ability of diffuse ultrasound to characterize surface breaking cracks in concrete. However, derived parameters are sensitive to the presence of partially opened zones along the crack whose pattern may differ from one sample to another. The aim of this letter is to study the variation of diffuse ultrasound parameters while the sample is driven by a low frequency bending load which alternatively opens and closes the crack, allowing to access supplementary information about its morphology. The results show the sensitivity of the method for various crack depths and highlight its potential for concrete nondestructive evaluation. PMID:23927227

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Physiological dysregulation and somatic decline among elders: modeling, applying and re-interpreting allostatic load.

    PubMed

    Leahy, Rachael; Crews, Douglas E

    2012-03-01

    Mortality rates continue to decline among post-reproductive individuals. This makes understanding long-term physiological responses to stress increasingly important. Allostatic load (AL) was developed to assess detrimental effects on the soma of responding to multiple stressors over a lifetime. AL arises from developmental experiences, genetic predispositions, environmental, psychosocial, life style and other stressors. In early life stress responsive systems are initiated that produce hormones that maintain the soma through continual allostatic responses. Later in life, systems designed to mitigate stressors may fail or be compromised, promoting unwanted somatic changes and dysregulation. This places a load on the regulatory system that impedes day-to-day stress responses, predisposing to cellular damage and degenerative diseases. Here we review 44 peer-reviewed 2005-2010 publications reportedly examining relationships between AL and risk factors, chronic diseases, morbidity and mortality in samples of elderly adults. The sum of results suggests that AL does assess aspects of physiological dysregulation and somatic decline, predicts detrimental age-related declines, and is associated with negative sociocultural attributes and psychological outcomes. Such consistent results and wide application of AL, while it is still being modeled and re-interpreted, suggest its perceived usefulness as a research and clinical tool. AL provides a possible biomarker of senescence, assessing it over the life span will aid in predicting future negative health outcomes. PMID:22816193

  18. 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.

  19. Dynamic response of a tunable phononic crystal under applied mechanical and magnetic loadings

    NASA Astrophysics Data System (ADS)

    Bayat, Alireza; Gordaninejad, Faramarz

    2015-06-01

    The dynamic response of a tunable phononic crystal consisting of a porous hyperelastic magnetoelastic elastomer subjected to a macroscopic deformation and an external magnetic field is theoretically investigated. Finite deformations and magnetic induction influence phononic characteristics of the periodic structure through geometrical pattern transformation and material properties. A magnetoelastic energy function is proposed to develop constitutive laws considering large deformations and magnetic induction in the periodic structure. Analytical and finite element methods are utilized to compute the dispersion relation and band structure of the phononic crystal for different cases of deformation and magnetic loadings. It is demonstrated that magnetic induction not only controls the band diagram of the structure but also has a strong effect on preferential directions of wave propagation.

  20. Tissue loads applied by a novel medical device for closing large wounds.

    PubMed

    Katzengold, Rona; Topaz, Moris; Gefen, Amit

    2016-02-01

    Closure of large soft tissue defects following surgery or trauma as well as closure of large chronic wounds constitutes substantial but common reconstructive challenges. In such cases, an attempt to use conventional suturing will result in high-tension closure, therefore alternative external skin stretching systems were developed. These types of devices were meant to reduce local mechanical loads in the skin and the underlying tissues, taking advantage of the viscoelastic properties of the skin, especially mechanical creep, for primary wound closure. Studies have shown the clinical advantages of skin stretching systems, however, quantitative bioengineering models, demonstrating closure of large wounds, are lacking. Here we present finite element (FE) modeling of the TopClosure(®) tension relief system (TRS) and its biomechanical efficacy in three (real) wound cases, compared with the alternative of a conventional surgical suturing closure technique. Our simulations showed that peak effective stresses on the skin were at least an order of magnitude greater (and sometimes nearly 2 orders-of-magnitude greater) when tension sutures were used with respect to the corresponding TRS data. For the tension suture simulations, the tensile stress was in the range of 415-648 MPa and in the TRS simulations, it was 16-30 MPa. Based on the present computational FE modeling, the TRS reduces localized tissue deformations and stress concentrations in skin and underlying tissues while closing large wounds, compared to the deformations and stresses that are inflicted during the process of suturing. This substantial reduction of loads allows surgeons to better employ the viscoelastic properties of the skin for primary wound closure. PMID:26750452

  1. Novelty detection applied to vibration data from a CX-100 wind turbine blade under fatigue loading

    NASA Astrophysics Data System (ADS)

    Dervilis, N.; Choi, M.; Antoniadou, I.; Farinholt, K. M.; Taylor, S. G.; Barthorpe, R. J.; Park, G.; Worden, K.; Farrar, C. R.

    2012-08-01

    The remarkable evolution of new generation wind turbines has led to a dramatic increase of wind turbine blade size. In turn, a reliable structural health monitoring (SHM) system will be a key factor for the successful implementation of such systems. Detection of damage at an early stage is a crucial issue as blade failure would be a catastrophic result for the entire wind turbine. In this study the SHM analysis will be based on experimental measurements of Frequency Response Functions (FRFs) extracted by using an input/output acquisition technique under a fatigue loading of a 9m CX-100 blade at the National Renewable Energy Laboratory (NREL) and National Wind Technology Center (NWTC) performed in the Los Alamos National Laboratory. The blade was harmonically excited at its first natural frequency using a Universal Resonant Excitation (UREX) system. For analysis, the Auto-Associative Neural Network (AANN) is a non-parametric method where a set of damage sensitive features gathered from the measured structure are used to train a network that acts as a novelty detector. This traditionally has a highly complex "bottleneck" structure with five layers in the AANN. In the current paper, a new attempt is also exploited based on an AANN with one hidden layer in order to reduce the theoretical and computational difficulties. Damage detection of composite bodies of blades is a "grand challenge" due to varying aerodynamic and gravitational loads and environmental conditions. A study of the noise tolerant capability of the AANN which is associated to its generalisation capacity is addressed. It will be shown that vibration response data combined with AANNs is a robust and powerful tool, offering novelty detection even when operational and environmental variations are present. The AANN is a method which has not yet been widely used in the structural health monitoring of composite blades.

  2. 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...

  3. Viewpoint-based ambient occlusion.

    PubMed

    González, Francisco; Sbert, Mateu; Feixas, Miquel

    2008-01-01

    A new ambient occlusion technique builds a channel between various viewpoints and an object's polygons, providing the information needed to create an occlusion map with multiple application possibilities. PMID:18350932

  4. 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

  5. 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

  6. Anti-inflammatory effects of locally applied enzyme-loaded ultradeformable vesicles on an acute cutaneous model.

    PubMed

    Simões, Sandra; Marques, Cláudia; Cruz, Maria Eugénia; Martins, Maria Bárbara Figueira

    2009-11-01

    Superoxide dismutase (SOD) and catalase (CAT) are active scavengers of reactive oxygen species and were incorporated into ultradeformable vesicles with the aim of increasing enzyme bioavailability (skin delivery). These special very adaptable vesicles have been formulated and optimized for enzyme transport in order to penetrate into or across the intact skin barrier. Anti-inflammatory activity of SOD-loaded, CAT-loaded and of SOD- and CAT-loaded ultradeformable vesicles applied epicutaneously was measured using different protein doses on the skin, on an arachidonic acid-induced mouse ear oedema. The biological anti-oedema activity is a measurement of drug-targeting potentiation in the organ. Delivery by means of deformable vesicles was compared to conventional vesicles or the absence of an enzyme carrier mediated transport. This was done at various times following prophylactic application of the test formulations. Positive reference groups were treated epicutaneously with several low molecular weight non-steroidal anti-inflammatory drugs (NSAIDs). The latter included indomethacin (3 mg kg(-1)), etofenamate (30 mg kg(-1)) and piroxicam (1 mg kg(-1)) and reduced the oedema by 94 +/- 4%, 81 +/- 4% and 42 +/- 5%, respectively, if measured 30 min after ear treatment with a NSAID. Of the enzyme-loaded carriers tested, only the enzyme-loaded ultradeformable vesicles reduced the swelling of ears significantly: SOD (90 microg kg(-1)), CAT (250 microg kg(-1)) and SOD (90 microg kg(-1)) plus CAT (250 microg kg(-1)) reduced the oedema by 70 +/- 12%, 65 +/- 10% and 61 +/- 19%, respectively, at t = 30 min. Aqueous enzyme solutions and empty carriers had no such effect. The combination of two enzymes resulted in no increased therapeutic effect, but the results are inconclusive since only two dose combinations were tested. The results presented in this study suggest that antioxidant enzymes delivered by means of ultradeformable lipid vesicles can serve as a novel region

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

    PubMed

    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

  8. 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.

  9. Applying a Stitched, Rod-Stiffened Concept to Heavily Loaded Structure

    NASA Technical Reports Server (NTRS)

    Jegley, Dawn C.

    2013-01-01

    NASA and the Boeing Company have worked to develop new low-cost, light-weight composite structures for aircraft. A stitched carbon-epoxy material system was developed to reduce the weight and cost of transport aircraft wing structure, first in the NASA Advanced Composites Technology (ACT) program in the 1990's and now in the Environmentally Responsible Aviation (ERA) Project. By stitching through the thickness of a dry carbon fiber material prior to cure, the labor associated with panel fabrication and assembly can be significantly reduced and the need for mechanical fasteners is almost eliminated. Stitching provides the benefit of reducing or eliminating delaminations, including those between stiffener flanges and skin. Stitching also reduces part count, and therefore, cost of the structure. The stitched panel concept used in the ACT program in the 1990's used simple blade-stiffeners as stringers, caps and clips. Today, the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) concept is being developed for application to advanced vehicle configurations. PRSEUS provides additional weight savings through the use of a stiffener with a thin web and a unidirectional carbon rod at the top of the web which provides structurally efficient stiffening. A comparison between the blade-stiffened structure and PRSEUS is presented focusing on highly loaded structure and demonstrating improved weight reduction.

  10. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

    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.

  12. An alternative treatment of occlusal wear: cast metal occlusal surface.

    PubMed

    Kumar, Sandeep; Arora, Aman; Yadav, Reena

    2012-01-01

    Acrylic resin denture teeth often exhibit rapid occlusal wear, which may lead to decrease in the chewing efficiency, loss of vertical dimension of occlusion, denture instability, temporomandibular joint disturbances, etc. There are various treatment options available like, use of highly cross linked acrylic teeth, amalgam or metal inserts on occlusal surface, use of composite, gold or metal occlusal surface, etc. Several articles have described methods to construct gold and metal occlusal surfaces, however, these methods are time-consuming, expensive and requires many cumbersome steps. These methods also requires the patient to be without the prosthesis for the time during which the laboratory procedures are performed. This article presents a quick, simple and relatively inexpensive procedure for construction of metal occlusal surfaces on complete dentures. PMID:22945724

  13. 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

  14. 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

    2014-01-01

    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 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. PMID:25479325

  15. 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

  16. Pulmonary veno-occlusive disease

    MedlinePlus

    ... occlusive disease is an extremely rare disease that causes high blood pressure in the lung arteries ( pulmonary hypertension ). ... In most cases, the cause of pulmonary veno-occlusive disease is ... arteries directly connected to the right side of the heart. The ...

  17. 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

  18. Other cerebrovascular occlusive disease.

    PubMed

    Camargo, Erica C S; Schaefer, Pamela W; Singhal, Aneesh B

    2016-01-01

    In this chapter we review the optimal imaging modalities for subacute and chronic stroke. We discuss the utility of computed tomography (CT) and multimodal CT imaging. Further, we analyze the importance of specific magnetic resonance imaging sequences, such as diffusion-weighted imaging for acute ischemic stroke, T2/fluid-attenuated inversion recovery for subacute and chronic stroke, and susceptibility imaging for detection of intracranial hemorrhages. Different ischemic stroke mechanisms are reviewed, and how these imaging modalities may aid in the determination of such. Further, we analyze how topographic patterns in ischemic stroke may provide important clues to the diagnosis, in addition to the temporal evolution of the stroke. Lastly, specific cerebrovascular occlusive diseases are reviewed, with emphasis on the optimal imaging modalities and their findings in each condition. PMID:27432673

  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. H{sub {infinity}} Control Theory Applied to Xenon Control for Load-Following Operation of a Nuclear Reactor

    SciTech Connect

    Chi, Sung Goo; Cho, Nam Zin

    2002-02-15

    A robust controller is designed by applying the H{sub {infinity}} optimal control theory to the xenon control for the load-following operation of a nuclear reactor. The set of reactor model equations for controller design is a stiff system. This singularly perturbed system arises from the interaction of slow dynamics modes (iodine and xenon concentrations) and fast dynamics modes (neutron density, fuel and coolant temperatures). The singular perturbation technique is used to overcome this stiffness problem. The design specifications are incorporated by the frequency weights using the mixed-sensitivity problem approach. The robustness of H{sub {infinity}} control is demonstrated by comparing it with linear quadratic Gaussian (LQG) control in the case of a measurement delay of the power measurement system.Since the gains and phase margins of H{sub {infinity}} control are larger than those of LQG control, the H{sub {infinity}} control is expected to provide excellent stability robustness and performance robustness against external disturbances and noises, model parameter variations, and modeling errors as well as hardware failures. It may also provide a practical design method because the design specifications can be easily implemented by the frequency weights.

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. 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. PMID:7590571

  6. Study of laser vas deferens occlusion.

    PubMed

    Xiao, X; Zhao, Q; Zhou, S; Jin, G; Wang, S; Luo, G

    2001-10-01

    The objective of this study was to determine threshold levels for high-power laser output Nd:YAG laser photocoagulation and to determine the possible reversibility of laser vas occlusion. The study included vas deferens of 220 rabbits and 20 samples of men in vitro, applying the Nd:YAG laser instrument, doing vasopuncture by a catheter needle, guiding the fiber into the vas, and performing the irradiation occlusion experiment to determine effective threshold value of photocoagulation. The effect and safety of occlusion were followed-up over a year, and reopening a experiment was done in 60 occluded nodes of rabbits. The postoperative sperm disappearance rate was 100%, and reopening rate was 72.7% without obvious complications. High-power lasers may be used as photocoagulation, and its merits are reliable, effective, and rapid recovery. The vas threshold lesion value of rabbits and men in vitro are 50 W/0.5 s, 45 W/1 s, respectively, and irradiation depth reached the middle-ring muscularis. PMID:11747875

  7. [Synthesis of new gene-loaded microbubbles serve as gene delivery vehicle applied in reporter gene transfer into cardiac myocytes].

    PubMed

    Wang, Guozhong; Hu, Shenjiang; Zheng, Zhelan; Sun, Jian; Zheng, Xia; Zhu, Zhaohui; Li, Jiang; Yao, Yumei

    2006-08-01

    To improve the stability and gene-carried capability of gene-attached microbubbles, the method for manufacture of albumin microbubbles was modified and new gene-loaded microbubbles were synthesized by incorporated gene-PEI complex into the shell of microbubbles. Agarose gel electrophoresis and bacteria transformation showed that PEI had the ability to provide the protection of plasmid DNA from ultrasonic degradation. The new gene-loaded microbubbles exhibited excellent acoustical and hemorheological properties. Moreover, they could carry more plasmid DNA than gene-attached microbubbles. beta-galactosidase plasmid transfection into cardiac myocytes was performed by using ultrasound targeted destruction of new gene-loaded microbubbles or gene-attached microbubbles. Gene expression in cardiac myocytes was detected by beta-galactosidase in situ staining and quantitive assay. It was shown that beta-galactosidase activity in cardiac myocytes was enhanced 107-fold by ultrasonic destruction of gene-loaded microbubbles compared with naked plasmid transfection and new gene-loaded microbubbles resulted in 6.85-fold increase in beta-galactosidase activity compared with optimal transfection mediated by gene-attached microbubbles. These results suggested that ultrasonic destruction of the gene-loaded microbubbles can enhance the cardiac myocytes exogenous gene transfer efficiency significantly and new gene-loaded microbubbles is an efficient and safe gene delivery vehicle. PMID:17002125

  8. Effect of Muscle Loads and Torque Applied to the Tibia on the Strain Behavior of the Anterior Cruciate Ligament: An In Vitro Investigation

    PubMed Central

    Fujiya, Hiroto; Kousa, Petteri; Fleming, Braden C; Churchill, David L; Beynnon, Bruce D

    2011-01-01

    Background Very little is known about the effects of applied torque about the long axis of the tibia in combination with muscle loads on anterior cruciate ligament biomechanics. The purpose of this study was to determine the effect of muscle contraction and tibial torques applied about the long axis of the tibia on anterior cruciate ligament strain behavior. Methods Six cadaver knee specimens were used to measure the strain behaviour of the anterior cruciate ligament. Internal and external axial torques were applied to the tibia when the knee was between 30° and 120° of flexion in combination with the conditions of no muscle load, isolated quadriceps load, and simultaneous quadriceps and hamstring loading. Findings The highest anterior cruciate ligament strain values were measured when the muscles were not loaded, when the knee was at 120° of flexion, and when internal tibial torques were applied to the knee. During muscle loading the highest anterior cruciate ligament strain values were measured at 30° of flexion and then the strain values gradually decreased with increase in knee flexion. During co-contraction of the quadriceps and hamstring muscles the anterior cruciate ligament was unstrained or minimally strained at 60°, 90° and 120° of knee flexion. Intepretation This study suggests that quadriceps and hamstring muscle co-contraction has a potential role in reducing the anterior cruciate ligament strain values when the knee is in deep flexion. These results can be used to gain insight into anterior cruciate ligament injury mechanisms and to design rehabilitation regimens. PMID:21816523

  9. Chewing efficiency and occlusal functional morphology in modern humans.

    PubMed

    Laird, Myra F; Vogel, Erin R; Pontzer, Herman

    2016-04-01

    The reduction of occlusal dimensions in early Homo is often proposed to be a functional adaptation to diet. With their smaller occlusal surfaces, species of early Homo are suggested to have reduced food-processing abilities, particularly for foods with high material properties (e.g., increased toughness). Here, we employ chewing efficiency as a measure of masticatory performance to test the relationships between masticatory function and food properties. We predicted that humans are more efficient when processing foods of lower toughness and Young's modulus values, and that subjects with larger occlusal surfaces will be less efficient when processing foods with higher toughness and Young's modulus, as the greater area spreads out the overall bite force applied to food particles. Chewing efficiency was measured in 26 adults using high-speed motion capture and surface electromyography. The dentition of each subject was cast and the occlusal surface was quantified using dental topographic analysis. Toughness and displacement-limited index were negatively correlated with chewing efficiency, but Young's modulus was not. Increased occlusal two-dimensional area and surface area were positively correlated with chewing efficiency for all foods. Thus, larger occlusal surface areas were more efficient when processing foods of greater toughness. These results suggest that the reduction in occlusal area in early Homo was associated with a reduction in chewing efficiency, particularly for foods with greater toughness. Further, the larger occlusal surfaces of earlier hominins such as Australopithecus would have likely increased chewing efficiency and increased the probability of fracture when processing tough foods. PMID:27086052

  10. 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. PMID:25419965

  11. 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

  12. 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:…

  13. 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

  14. Investigation of the impact of transient heat loads applied by laser irradiation on ITER-grade tungsten

    NASA Astrophysics Data System (ADS)

    Huber, A.; Arakcheev, A.; Sergienko, G.; Steudel, I.; Wirtz, M.; Burdakov, A. V.; Coenen, J. W.; Kreter, A.; Linke, J.; Mertens, Ph; Philipps, V.; Pintsuk, G.; Reinhart, M.; Samm, U.; Shoshin, A.; Schweer, B.; Unterberg, B.; Zlobinski, M.

    2014-04-01

    Cracking thresholds and crack patterns in tungsten targets after repetitive ITER-like edge localized mode (ELM) pulses have been studied in recent simulation experiments by laser irradiation. The tungsten specimens were tested under selected conditions to quantify the thermal shock response. A Nd:YAG laser capable of delivering up to 32 J of energy per pulse with a duration of 1 ms at the fundamental wavelength λ = 1064 nm has been used to irradiate ITER-grade tungsten samples with repetitive heat loads. The laser exposures were performed for targets at room temperature (RT) as well as for targets preheated to 400 °C to measure the effects of the ELM-like loading conditions on the formation and development of cracks. The magnitude of the heat loads was 0.19, 0.38, 0.76 and 0.90 MJ m-2 (below the melting threshold) with a pulse duration of 1 ms. The tungsten surface was analysed after 100 and 1000 laser pulses to investigate the influence of material modification by plasma exposures on the cracking threshold. The observed damage threshold for ITER-grade W lies between 0.38 and 0.76 GW m-2. Continued cycling up to 1000 pulses at RT results in enhanced erosion of crack edges and crack edge melting. At the base temperature of 400 °C, the formation of cracks is suppressed.

  15. The use of a lock-in amplifier to apply digital image correlation to cyclically loaded components

    NASA Astrophysics Data System (ADS)

    Fruehmann, R. K.; Dulieu-Barton, J. M.; Quinn, S.; Tyler, J. P.

    2015-05-01

    An approach for processing strain data obtained from Digital Image Correlation (DIC) that can be used directly on components subject to cyclic loading, such as in fatigue testing, is described. A key challenge addressed herein is obtaining an accurate and precise surface strain map without recourse to expensive high speed cameras to capture data to map the load cycle. The basis of the approach is the application of a lock-in amplifier to the strain data obtained from images taken from low-cost low-frame rate cameras. The technique enables images to be captured throughout a fatigue test and hence evaluate the effect of any damage on the strain field, without interrupting the test. The methodology is assessed using an aluminium disc in diametric compression. It is demonstrated that the approach enables accurate strain maps to be obtained using a range of loading frequencies that are greater than the camera frame rate. A realistic example application of the technique on a fatigue test with an evolving crack in a T-shaped specimen is presented.

  16. Dynamic analysis of double-row self-aligning ball bearings due to applied loads, internal clearance, surface waviness and number of balls

    NASA Astrophysics Data System (ADS)

    Zhuo, Yaobin; Zhou, Xiaojun; Yang, Chenlong

    2014-11-01

    In this paper, a three degrees of freedom (dof) model was established for a double-row self-aligning ball bearing (SABB) system, and was applied to study the dynamic behavior of the system during starting process and constant speed rotating process. A mathematical model was developed concerning stiffness and damping characteristics of the bearing, as well as three-dimensional applied load, rotor centrifugal force, etc. Balls and races were all considered as nonlinear springs, and the contact force between ball and race was calculated based on classic Hertzian elastic contact deformation theory and deformation compatibility theory. The changes of each ball's contact force and loaded angle of each row were taken into account. In order to solve the nonlinear dynamical equilibrium equations of the system, these equations were rewritten as differential equations and the fourth order Runge-Kutta method was used to solve the equations iteratively. In order to verify accuracy of the dynamical model and correctness of the numerical solution method, a kind of SABB-BRF30 was chosen for case studies. The effects of several important governing parameters, such as radial and axial applied loads, normal internal, inner and outer races waviness, and number of balls were investigated. These parametric studies led to a complete characterization of the shaft-bearing system vibration transmission. The research provided a theoretical reference for new type bearing design, shaft-bearing system kinetic analysis, optimal design, etc.

  17. Pulmonary veno-occlusive disease

    MedlinePlus

    ... disorder. Alternative Names Pulmonary vaso-occlusive disease Images Respiratory system References Channick RN, Rubin LJ. Pulmonary hypertension. In: Mason RJ, Broaddus VC, Martin TR, et al., eds. Murray and Nadel's Textbook of Respiratory Medicine . 5th ed. Philadelphia, PA: Elsevier Saunders; 2010: ...

  18. Molecular studies of the structural ecology of natural occlusal caries.

    PubMed

    Dige, Irene; Grønkjær, Lene; Nyvad, Bente

    2014-01-01

    Microbiological studies of occlusal dental biofilms have hitherto been hampered by inaccessibility to the sampling site and demolition of the original biofilm architecture. This study shows for the first time the spatial distribution of bacterial taxa in vivo at various stages of occlusal caries, applying a molecular methodology involving preparation of embedded hard dental tissue slices for fluorescence in situ hybridization (FISH) and confocal microscopy. Eleven freshly extracted teeth were classified according to their occlusal caries status. The teeth were fixed, embedded, sectioned and decalcified before FISH was performed using oligonucleotide probes for selected abundant species/genera associated with occlusal caries including Streptococcus, Actinomyces, Veillonella, Fusobacterium, Lactobacillus and Bifidobacterium. The sites showed distinct differences in the bacterial composition between different ecological niches in occlusal caries. Biofilm observed along the entrance of fissures showed an inner layer of microorganisms organized in palisades often identified as Actinomyces, covered by a more loosely structured bacterial layer consisting of diverse genera, similar to supragingival biofilm. Biofilm within the fissure proper seemed less metabolically active, as judged by low fluorescence signal intensity and presence of material of non-bacterial origin. Bacterial invasion (often Lactobacillus and Bifidobacterium spp.) into the dentinal tubules was seen only at advanced stages of caries with manifest cavity formation. It is concluded that the molecular methodology represents a valuable supplement to previous methods for the study of microbial ecology in caries by allowing analysis of the structural composition of the undisturbed biofilm in caries lesions in vivo. PMID:24852305

  19. 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.

  20. The Impact of Occlusal Function on Structural Adaptation in Alveolar Bone of the Growing Pig, Sus Scrofa

    PubMed Central

    Yeh, Kuang-Dah; Popowics, Tracy Ellen

    2010-01-01

    Objectives This study investigated the effects of growth and tooth loading on the structural adaptation of the developing alveolar bone adjacent to the tooth root as the tooth erupted into function. Growth and occlusal function were expected to lead to increased alveolar bone density. Meanwhile, the supporting alveolar bone was expected to develop a dominant trabecular orientation (anisotropy) only after occlusal loading. Design Minipigs with erupting and occluding mandibular first molars (M1’s) were used to study the effects of growth and occlusal function on developing alveolar bone structure through comparison of alveolar bone surrounding M1’s. A second minipig model with one side upper opponent teeth extracted prior to occlusal contact with the M1 was raised until the non-extraction side M1’s developed full occlusal contact. The comparisons between extraction and non-extraction side M1 alveolar bone were used to emphasize the impact of occlusal loading on alveolar bone structure. Specimens were scanned on a Scanco Medical μCT 20 at a 22μm voxel resolution for structural analysis. Results With growth and occlusal function a distinct alveolar bone proper tended to develop immediately adjacent to the tooth root. The cancellous bone had thicker but fewer and more separated trabeculae after growth or occlusal loading. On the other hand, occlusal function did not lead to increased alveolar structural anisotropy. Conclusion During tooth eruption, growth and masticatory loads effect structural change in alveolar bone. The impact of occlusal function on cancellous bone anisotropy may need a more extensive period of time to demonstrate. PMID:20855059

  1. Nonlinear dynamic response of a 'flexible-and-heavy' printed circuit board (PCB) to an impact load applied to its support contour

    NASA Astrophysics Data System (ADS)

    Suhir, E.; Vujosevic, M.; Reinikainen, T.

    2009-02-01

    Based on the developed simple and physically meaningful analytical ('mathematical') stress model, we evaluate some major parameters (amplitude, frequency, maximum acceleration, stresses and strains) of the response of a 'flexible-and-heavy' square simply supported printed circuit board (PCB) to an impact drop load applied to its support contour. The analysis is restricted to the first mode of vibrations and is carried out in application to the PCB design employed in an advanced accelerated test setup (test vehicle). This setup is aimed at the assessment of the performance, in accelerated test conditions on the board level, of packaging materials (and, first of all, BGA solder joint interconnections) subjected to dynamic (drop or shock) loading. It is anticipated that heavy masses could be mounted on the PCB to accelerate its dynamic response to an impact load. These masses are expected to be small in size, so that while changing the total mass of the board and generating significant inertia forces, they do not affect the board's flexural rigidity or its stiffness with respect to the in-plane loading. The PCB's contour is considered non-deformable, which is indeed the case in many practical situations. This circumstance, if the drop height and/or the induced inertia forces are significant, leads to elevated in-plane ('membrane') stresses in the PCB and, as a result of that, to the nonlinear response of the board to the impact load: the relationship between the magnitude of the load (determined by the initial impact velocity) and the induced PCB deflections becomes geometrically nonlinear, with a rigid cubic characteristic of the restoring force. The carried out numerical example, although reflects the characteristics of the PCB and loading conditions in an actual experimental setup, is merely an illustration of the general concept and is intended to demonstrate the abilities of the suggested method. Predictions based on this method agree well with the finite element

  2. 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

  3. 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.

  4. Thermography in Occlusive Cerebrovascular Diseases

    PubMed Central

    Mawdsley, C.; Samuel, E.; Sumerling, M. D.; Young, G. B.

    1968-01-01

    Cooling of the skin over the medial supraorbital region in 80% of patients who have an occlusion or severe stenosis of a carotid artery can be demonstrated by facial thermography. Minor stenotic lesions in the carotid arteries do not produce characteristic thermographic changes, while thermography is of no help in the diagnosis of vertebrobasilar arterial disease. Thermographic changes suggestive of carotid arterial lesions are found occasionally in patients whose angiograms are normal, owing to variations in the size of the frontal sinuses, or factors such as fever or inflammatory lesions. It is suggested that facial thermography is of value in the preliminary investigation of patients with occlusive cerebrovascular disease. ImagesFig. 1Fig. 2Fig. 3Fig. 4Fig. 5Fig. 6 PMID:5676953

  5. Retinal vein occlusion: current treatment.

    PubMed

    Lattanzio, Rosangela; Torres Gimeno, Ana; Battaglia Parodi, Maurizio; Bandello, Francesco

    2011-01-01

    Retinal vein occlusion (RVO) is a pathology noted for more than 150 years. Although a lot has been written on the matter, it is still a frequent condition with multifactorial etiopathogenesis with many unclear aspects. The RVO pathogenesis has varied systemic and local implications that make it difficult to elaborate treatment guidelines. The management of the patient with RVO is very complex and a multidisciplinary approach is required in order to identify and correct the associated risk factors. Laser therapy remains the gold standard in RVO, but only modest functional improvement has been shown in branch retinal occlusion forms. Multicenter studies of intravitreal drugs present them as an option to combine with laser. Anti-vascular endothelial growth factor, corticosteroids and sustained-release implants are the future weapons to stop disease progression and get a better visual outcome. Consequently, it is useful to clarify some aspects of the pathology that allow a better patient management. PMID:20938213

  6. 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.

  7. Management of total restenotic occlusions.

    PubMed

    Werner, Gerald S; Moehlis, Hiller; Tischer, Karlheinz

    2009-05-01

    Among lesions with in-stent restenosis (ISR), the in-stent chronic re-occlusions (ISR-CTO) is a subset with particularly unfavourable features regarding both the repeat procedure success and the prevention of lesion recurrence. A review of the literature and personal databases reveals that the prevalence of complete occlusive ISR represents about 5-10% of all CTO lesions, with little evidence regarding the successful long-term treatment. In fact, these lesions had been excluded from large contemporary trials dealing with the best modality for ISR management, and which showed eventually the superiority of drug-eluting stents (DES) as compared to brachytherapy. Only a limited experience exists with brachytherapy for ISR-CTOs, showing an inferior outcome as compared to non-occlusive ISRs. The lack of large study experience is true also for DES, so that only anecdotal experience in small series of patients is available. In some of the recent studies of DES in CTOs, again, ISR-CTOs were not included. Our own experience shows a slightly lower primary success rate of about 70% in ISR-CTOs as compared to 85% in primary CTOs, with a slightly higher recurrence rate with DES of 25%. ISR-CTOs are a clinical problem that had not been systematically addressed. However, we hope that this lesion subset may be of less relevance in the future when the use of DES in lesions which are prone for lesion recurrence will lead to less diffuse and occlusive ISR, and leaves rather focal and better manageable recurrent lesions. PMID:19736077

  8. Venous occlusive diseases in women.

    PubMed

    Ozsvath, Kathleen J; Moore, Colleen J

    2013-04-01

    Women have a high incidence of chronic venous disease. Venous occlusive disease can lead to significant morbidity and even death. Factors such as genetics, medications, and diseases can play a role in the development of venous thrombosis. In women, pregnancy can lead to a hypercoagulable state and a greater risk of venous complication. Awareness and education will be very important in the future to help identify those patients at risk. PMID:23522718

  9. Existing concepts and a search for evidence: a review on implant occlusion.

    PubMed

    Ben-Gal, Gilad; Lipovetsky-Adler, Mordechai; Haramaty, Orith; Sharon, Eldad; Smidt, Ami

    2013-07-01

    The prevalence of dental implant treatment raises the question: What factors may challenge osseointegration? The dental literature presents two main approaches, which are well-documented: loss of bone around the implant due to infection and a presumed association between implant load and bone loss. This article discusses the effect of load or overload on the bone loss around dental implants. The dental literature is reviewed to assess the scientific evidence related to the effect of occlusal load on osseointegration. Recommendations found in the literature for occlusal schemes for implant-supported prostheses are examined and discussed, and statements regarding implant occlusion are assessed for their validity today, after more than four decades of implants service in prosthetic dentistry. PMID:24568248

  10. 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.

  11. Rehabilitation of occlusion - science or art?

    PubMed

    Koyano, K; Tsukiyama, Y; Kuwatsuru, R

    2012-07-01

    The primary objective of rehabilitating occlusion is to improve stomatognathic function in patients experiencing dysfunction in mastication, speech, and swallowing as a consequence of tooth loss. The procedure of occlusal treatment involves improving the morphology and the stomatognathic function. Several practical methods and morphological endpoints have been described in occlusal rehabilitation. We made a selection of these (mandibular position, occlusal plane, occlusal guidance, occlusal contact, face-bow transfer, use of an adjustable articulator and occlusal support) and performed a literature review to verify the existence of compelling scientific evidence for each of these. A literature search was conducted using Medline/PubMed in March 2011. Over 400 abstracts were reviewed, and more than 50 manuscripts selected. An additional hand search was also conducted. Of the many studies investigating stomatognathic function in relation to specific occlusal schemes, most studies were poorly designed and of low quality, thus yielding ambiguous results. Overall, there is no scientific evidence that supports any specific occlusal scheme being superior to others in terms of improving stomatognathic function, nor that sophisticated methods are superior to simpler ones in terms of clinical outcomes. However, it is obvious that the art of occlusal rehabilitation requires accurate, reproducible, easy and quick procedures to reduce unnecessary technical failures and/or the requirement for compensatory adjustments. Therefore, despite the lack of scientific evidence for specific treatments, the acquisition of these general skills by dentists and attaining profound knowledge and skills in postgraduate training will be necessary for specialists in charge of complicated cases. PMID:22489962

  12. Functional Role of HSP47 in the Periodontal Ligament Subjected to Occlusal Overload in Mice

    PubMed Central

    Mimura, Hiroaki; Takaya, Tatsuo; Matsuda, Saeka; Nakano, Keisuke; Muraoka, Rina; Tomida, Mihoko; Okafuji, Norimasa; Fujii, Takeo; Kawakami, Toshiyuki

    2016-01-01

    We carried out an experiment to induce traumatic occlusion in mice periodontal tissue and analyzed the expression of HSP47. Continuous traumatic occlusion resulted to damage and remodeling of periodontal ligament as well as increase in osteoclasts and bone resorption. Four days after traumatic occlusion, osteoclasts did not increase but Howship's lacunae became enlarged. That is, the persistent occlusal overload can destroy collagen fibers in the periodontal ligament. This was evident by the increased in HSP47 expression with the occlusal overload. HSP47 is maintained in fibroblasts for repair of damaged collagen fibers. On the other hand, osteoclasts continue to increase although the load was released. The osteoclasts that appeared on the alveolar bone surface were likely due to sustained activity. The increase in osteoclasts was estimated to occur after load application at day 4. HSP47 continued to increase until day 6 in experiment 2 but then reduced at day 10. Therefore, HSP47 appears after a period of certain activities to repair damaged collagen fibers, and the activity was returned to a state of equilibrium at day 30 with significantly diminished expression. Thus, the results suggest that HSP47 is actively involved in homeostasis of periodontal tissue subjected to occlusal overload. PMID:27076780

  13. 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

  14. Vertebral artery occlusion and oral contraceptives.

    PubMed Central

    Ask-Upmark, E; Bickerstaff, E R

    1976-01-01

    If vertebral artery occlusion occurs in degenerative arterial disease it is almost invariably left-sided, but in vertebral artery deficiency syndromes associated with oral contraceptives a striking preponderance of right-sided involvement has been shown. This observation adds support to the view that causes other than changes in the wall of the vessel at the site of occlusion must be sought as an explanation of the occlusion. PMID:1252812

  15. Numerical simulation of the fracture process in ceramic FPD frameworks caused by oblique loading.

    PubMed

    Kou, Wen; Qiao, Jiyan; Chen, Li; Ding, Yansheng; Sjögren, Göran

    2015-10-01

    Using a newly developed three-dimensional (3D) numerical modeling code, an analysis was performed of the fracture behavior in a three-unit ceramic-based fixed partial denture (FPD) framework subjected to oblique loading. All the materials in the study were treated heterogeneously; Weibull׳s distribution law was applied to the description of the heterogeneity. The Mohr-Coulomb failure criterion with tensile strength cut-off was utilized in judging whether the material was in an elastic or failed state. The simulated loading area was placed either on the buccal or the lingual cusp of a premolar-shaped pontic with the loading direction at 30°, 45°, 60°, 75° or 90° angles to the occlusal surface. The stress distribution, fracture initiation and propagation in the framework during the loading and fracture process were analyzed. This numerical simulation allowed the cause of the framework fracture to be identified as tensile stress failure. The decisive fracture was initiated in the gingival embrasure of the pontic, regardless of whether the buccal or lingual cusp of the pontic was loaded. The stress distribution and fracture propagation process of the framework could be followed step by step from beginning to end. The bearing capacity and the rigidity of the framework vary with the loading position and direction. The framework loaded with 90° towards the occlusal surface has the highest bearing capacity and the greatest rigidity. The framework loaded with 30° towards the occlusal surface has the least rigidity indicating that oblique loading has a major impact on the fracture of ceramic frameworks. PMID:26143353

  16. 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. PMID:25284468

  17. Angiographic evidence of coronary occlusion and resolution

    PubMed Central

    Kavanagh-Gray, Doris

    1974-01-01

    A case of myocardial infarction with angiographically demonstrated occlusion of the left anterior descending coronary artery is presented. Repeat angiography 18 months later revealed patent coronary arteries despite persistent electrocardiographic infarction pattern. Coronary artery occlusion resulting in infarction may not, therefore, be permanent. ImagesFIG. 2 PMID:4824968

  18. Bilateral mechanical rotational vertebral artery occlusion.

    PubMed

    Dargon, Phong T; Liang, Conrad W; Kohal, Anmol; Dogan, Aclan; Barnwell, Stanley L; Landry, Gregory J

    2013-10-01

    Rotational vertebral artery occlusion, or bow hunter's stroke, is reversible, positional symptomatic vertebrobasilar ischemia. The typical mechanism of action is obstruction of a dominant vertebral artery with contralateral head rotation in the setting of baseline ipsilateral vertebral artery stenosis or occlusion. Here we present a rare case of mechanical occlusion of bilateral patent vertebral arteries manifesting as near syncope with rightward head rotation. Diagnostic cerebral angiography showed dynamic right C5 vertebral occlusion and left C2 vertebral occlusion. The patient underwent right C4/5 transverse process decompression. Postoperative angiogram showed patent flow through the right vertebral artery in neutral position and with head turn with resultant resolution of symptoms. PMID:23465174

  19. 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.

  20. 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

  1. Occlusion Detection by Height Gradient for True Orthophoto Generation, Using LIDAR Data

    NASA Astrophysics Data System (ADS)

    Oliveira, H. C.; Galo, M.

    2013-05-01

    Nowadays, the use of orthophoto in urban areas has become common. It is known that in most parts of urban areas there are a great number of tall buildings which can cause occlusion regions during image acquisition. These occlusions appear both in aerial images and in the orthophotos generated from these images. It happens due to perspective projection of the imaging sensor, and also if digital models that represent only relief is used in the orthorectification process, instead of the Digital Surface Model (DSM) that takes into account the relief and all objects on the surface. Considering this context, the aim of this article is to introduce an alternative procedure for occlusion detection in aerial images, using LiDAR (Light Detection And Ranging) data, aiming at the generation of true orthophotos. The presented method for occlusion detection is based on height gradient computation applied to a DSM of the region, instead of the building model that is considered in some approaches. These height gradients computed in radial directions are important for the identification of the beginning of the occlusions in these directions. The final limits of the occlusions are obtained from the projection of these initial points in the DSM. To evaluate the proposed method, both simulated and real data were considered. The simulated data correspond to an ideal urban area, without noise, and this experiment was only used to validate the implementation method. The real data set is composite by digital aerial images and LiDAR data. The LiDAR data available has the average density of 8 points/m2. As preliminary results, the occlusion areas were detected and highlighted in the orthorectified images. To accomplish the evaluation of the proposed method, besides a visual analysis, a numerical evaluation based on index of completeness was computed, using as reference a manual detection of occlusion. It is possible to observe the potential of the proposed occlusion detection method

  2. Accuracy of reflectance photoplethysmography on detecting cuff-induced vascular occlusions.

    PubMed

    Abay, T Y; Kyriacou, P A

    2015-08-01

    Photoplethysmography (PPG) is a noninvasive optical technique, which can also be used to derive important parameters other than arterial oxygen saturation (SpO2). In this work, the accuracy of the technique on detecting changes in blood perfusion during different levels of vascular occlusions has been explored. A dual-wavelength, reflectance PPG probe was applied on the left forearm of 10 healthy volunteers and raw PPG signals were acquired by a research PPG processing system. The raw PPG signals were separated into pulsatile AC and continuous DC PPG components. The signals were used to estimate SpO2 and changes in concentration of oxygenated, deoxygenated, and total haemoglobin. Different levels of occlusions, from 20 mmHg to total occlusion were induced by a pressure-cuff on the left arm. The system was able to indicate all the occlusions. In particular, the haemoglobin concentration changes estimated from PPG were in high agreement with Near Infrared Spectroscopy measurements. PMID:26736398

  3. A Single Visit Direct Technique to Provisionally Restore Occlusion for a Full-Mouth Rehabilitation: A Clinical Report.

    PubMed

    El-Kerdani, Tarek; Nimmo, Arthur

    2016-01-01

    Attrition of the dentition can negatively affect esthetics and function. When reconstructing patients with attrition who require restoration at increased occlusal vertical dimension (OVD), it is necessary to first evaluate the OVD using a removable interim prosthesis to ensure that the patient will tolerate the new position. The transition to fixed interim prostheses has to be carefully planned to achieve the desired OVD. One approach is to prepare all teeth in a single day and place full-arch interim prostheses; however, this can be tiring for the patient and prosthodontist. An alternative approach is to prepare one arch and place interim prostheses, while using composite resin in the opposing arch to maintain the newly established OVD. A diagnostic wax-up at the proposed OVD is completed and duplicated in stone. A vacuform matrix is loaded with composite resin and applied to the unprepared etched teeth of the opposing arch to restore form and occlusion until full contour interim prostheses are placed at a later visit. PMID:25659611

  4. Enhanced removal of contaminant using the biological film, anoxic-anaerobic-aerobic and electro-coagulation process applied to high-load sewage treatment.

    PubMed

    Wang, Wenlong; Chen, Shaohua; Bao, Keqian; Gao, Jingqing; Zhang, Ruiqin; Zhang, Zhenya; Sugiura, Norio

    2014-01-01

    In order to explore a new treatment process applying to decentralized domestic sewage treatment, and enhance removal of total nitrogen (TN), total phosphorus (TP) and chemical oxygen demand (COD), a novel system integrating anoxic-anaerobic-aerobic (reversed A2O) and electro-coagulation (EC) process was studied, and complex biological media (CMB) was used as suspended carrier for biofilm development. In this work, TN, TP and COD removal performance were investigated with consideration of three major factors, hydraulic retention time (HRT), organic loading rate (OLR) and sludge recycle ratio (SRR). Results showed that (1) The optimum HRT was between 8 and 12 h. The removal efficiencies of TN, TP and COD were about 68%, 95% and 95%, respectively. (2) With the increase of OLR, the removal efficiency of TN increased slowly. But it increased first and then declined for COD and TP removal. Their maximum were attained when OLR was 1.8 g(COD)/(L d), and they were 96% and 93%, respectively. (3) The optimum SRR was 75%. The COD, TN and TP removal efficiencies were about 95%, 72% and 98%, respectively. In this system, the maximum TN and COD removal were achieved in anoxic tank, but it was achieved in aerobic tank for TP removal. The EC bed enhanced the effluent quality, especially the efficiency in advanced P removal. From these results, it was concluded that the new process could be a reliable option for providing excellent effluent quality. PMID:24645465

  5. 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.

  6. 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. PMID:27009171

  7. Retinal vein occlusion: pathophysiology and treatment options

    PubMed Central

    Karia, Niral

    2010-01-01

    This paper reviews the current thinking about retinal vein occlusion. It gives an overview of its pathophysiology and discusses the evidence behind the various established and emerging treatment paradigms. PMID:20689798

  8. Conventional occlusion versus pharmacologic penalization for amblyopia

    PubMed Central

    Li, Tianjing; Shotton, Kate

    2013-01-01

    Background Amblyopia is defined as defective visual acuity in one or both eyes without demonstrable abnormality of the visual pathway, and is not immediately resolved by wearing glasses. Objectives To assess the effectiveness and safety of conventional occlusion versus atropine penalization for amblyopia. Search methods We searched CENTRAL, MEDLINE, EMBASE, LILACS, the WHO International Clinical Trials Registry Platform, preference lists, science citation index and ongoing trials up to June 2009. Selection criteria We included randomized/quasi-randomized controlled trials comparing conventional occlusion to atropine penalization for amblyopia. Data collection and analysis Two authors independently screened abstracts and full text articles, abstracted data, and assessed the risk of bias. Main results Three trials with a total of 525 amblyopic eyes were included. One trial was assessed as having a low risk of bias among these three trials, and one was assessed as having a high risk of bias. Evidence from three trials suggests atropine penalization is as effective as conventional occlusion. One trial found similar improvement in vision at six and 24 months. At six months, visual acuity in the amblyopic eye improved from baseline 3.16 lines in the occlusion and 2.84 lines in the atropine group (mean difference 0.034 logMAR; 95% confidence interval (CI) 0.005 to 0.064 logMAR). At 24 months, additional improvement was seen in both groups; but there continued to be no meaningful difference (mean difference 0.01 logMAR; 95% CI −0.02 to 0.04 logMAR). The second trial reported atropine to be more effective than occlusion. At six months, visual acuity improved 1.8 lines in the patching group and 3.4 lines in the atropine penalization group, and was in favor of atropine (mean difference −0.16 logMAR; 95% CI −0.23 to −0.09 logMAR). Different occlusion modalities were used in these two trials. The third trial had inherent methodological flaws and limited inference could

  9. 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.

  10. A mechanistic approach to blood flow occlusion.

    PubMed

    Loenneke, J P; Wilson, G J; Wilson, J M

    2010-01-01

    Low-Intensity occlusion training provides a unique beneficial training mode for promoting muscle hypertrophy. Training at intensities as low as 20% 1RM with moderate vascular occlusion results in muscle hypertrophy in as little as three weeks. The primary mechanisms by which occlusion training is thought to stimulate growth include, metabolic accumulation, which stimulates a subsequent increase in anabolic growth factors, fast-twitch fiber recruitment (FT), and increased protein synthesis through the mammalian target of rapamycin (mTOR) pathway. Heat shock proteins, Nitric oxide synthase-1 (NOS-1) and Myostatin have also been shown to be affected by an occlusion stimulus. In conclusion, low-intensity occlusion training appears to work through a variety of mechanisms. The research behind these mechanisms is incomplete thus far, and requires further examination, primarily to identify the actual metabolite responsible for the increase in GH with occlusion, and determine which mechanisms are associated to a greater degree with the hypertrophic/anti-catabolic changes seen with blood flow restriction. PMID:19885776

  11. Precision metal occlusal surfaces for removable partial dentures.

    PubMed

    Barco, M T; Synnott, S A

    1989-01-01

    The prosthodontist is often limited in developing the desired occlusal pattern when integrating removable partial dentures with natural dentitions or fixed partial dentures. A technique that allows the development of an esthetic, accurate metal occlusal surface for a removable partial denture is described. The occlusion developed allows an occlusal harmony with the removable partial denture that is not possible with stock denture teeth or metal occlusal surfaces developed with stock denture teeth. PMID:2700630

  12. The impact of surface loading and dosing scheme on the skin uptake of fragrances.

    PubMed

    Berthaud, Fabienne; Smith, Benjamin; Boncheva, Mila

    2013-12-01

    This study compared the skin uptake of γ-undecalactone, decanol, and dodecyl acetate in an in vitro, un-occluded penetration assay in which they were applied to porcine skin at different finite loadings and application schemes. The pattern of fractional uptake differed between the chemicals and did not show the often assumed inverse correlation with surface loading. Furthermore, the mass uptake of identical cumulative amounts of the chemicals was not always additive. These results show that the uptake of fragrances in absence of occlusion and at finite loadings is chemical-specific and depends on the surface loading, the application scheme, and most probably, on the effects of the chemicals on the skin barrier efficiency. The observed lack of additivity might explain some of the differences in the responses observed in patch and repeated open application tests, and the boosting of the allergic state in sensitized individuals by sub-clinical exposures. PMID:24041533

  13. Fast and effective occlusion culling for 3D holographic displays by inverse orthographic projection with low angular sampling.

    PubMed

    Jia, Jia; Liu, Juan; Jin, Guofan; Wang, Yongtian

    2014-09-20

    Occlusion culling is an important process that produces correct depth cues for observers in holographic displays, whereas current methods suffer from occlusion errors or high computational loads. We propose a fast and effective method for occlusion culling based on multiple light-point sampling planes and an inverse orthographic projection technique. Multiple light-point sampling planes are employed to remove the hidden surfaces for each direction of the view of the three-dimensional (3D) scene by forward orthographic projection, and the inverse orthographic projection technique is used to determine the effective sampling points of the 3D scene. A numerical simulation and an optical experiment are performed. The results show that this approach can realize accurate occlusion effects, smooth motion parallax, and continuous depth using low angular sampling without any extra computation costs. PMID:25322109

  14. 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.

  15. Effect of selective occlusion of the umbilical arteries and/or veins on uterine blood flow in sheep.

    PubMed

    Hasaart, T H; de Haan, J; Horiguchi, T

    1986-01-01

    Maternal uterine blood flow was depressed during total umbilical cord occlusion, probably based on an increased fetal cotyledonary tissue pressure (Hasaart and de Haan (1985) Eur. J. Obstet. Gynec. Reprod. Biol., 19, 125-131). This supposed mechanism was further analysed by performing selective occlusions of the umbilical arteries and/or veins (mean occlusion time 35 s). An occluding device which allowed separate occlusion of umbilical veins and arteries was applied to the umbilical cord in 7 chronically prepared fetal lambs between 106 and 135 days gestation. Median uterine artery blood flow (UBF) was measured with an electromagnetic flow meter. During occlusion of both umbilical veins (VV, n = 22) in 6 animals a maximal decrease in UBF to 87.5% of control value (P less than 0.001) was found at the end occlusion, followed by a gradual return to control value in the post occlusion period. Occlusion of both umbilical arteries (AA, n = 29) in 5 animals was accompanied by a slight increase in UBF to 103% of control value (P less than 0.01). Total occlusion of the umbilical arteries and veins simultaneously (n = 17) in 4 animals did not result in any change in UBF. The changes in volume and turgor in the fetal cotyledonary tissue associated with the arterial and venous occlusions should lead to respectively a decrease (AA) and increase (VV) in resistance to maternal flow, causing the changes in uterine blood flow. It is concluded that volume changes in the fetal compartment of the sheep placenta affect maternal uterine blood flow. PMID:3956829

  16. 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.

  17. 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. PMID:25737904

  18. Studies on the biodegradation of nonionic surfactants applied in the polyester fiber industry. II. Effect of activated sludge load on microorganisms.

    PubMed

    Rzechowska, E

    1976-01-01

    The effect of selected nonionic surfactants Cirrasol FP, Cirrasol SF 200 and Cirrasol TCS on activated sludge organisms purifying wastes from the polyestre fibre industry was studied. The toxic effect of the mentioned surfactants towards bacteria, protozoa, rotifera and nematoda occurred at loads exceeding 0.32 mg surfactant/mg d.w./day and in periods of large fluctuations of the employed loads. Morphological changes of activated sludge flocs are also observed in similar conditions. PMID:62498

  19. Time management in acute vertebrobasilar occlusion.

    PubMed

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

    2009-03-01

    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. PMID:18704570

  20. 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.

  1. Metamorphopsia Associated with Branch Retinal Vein Occlusion

    PubMed Central

    Manabe, Koichiro; Tsujikawa, Akitaka; Osaka, Rie; Nakano, Yuki; Fujita, Tomoyoshi; Shiragami, Chieko; Hirooka, Kazuyuki; Uji, Akihito; Muraoka, Yuki

    2016-01-01

    Purpose To apply M-CHARTS for quantitative measurements of metamorphopsia in eyes with acute branch retinal vein occlusion (BRVO) and to elucidate the pathomorphology that causes metamorphopsia. Methods This prospective study consisted of 42 consecutive patients (42 eyes) with acute BRVO. Both at baseline and one month after treatment with ranibizumab, metamorphopsia was measured with M-CHARTS, and the retinal morphological changes were examined with optical coherence tomography. Results At baseline, metamorphopsia was detected in the vertical and/or horizontal directions in 29 (69.0%) eyes; the mean vertical and horizontal scores were 0.59 ± 0.57 and 0.52 ± 0.67, respectively. The maximum inner retinal thickness showed no association with the M-CHARTS score, but the M-CHARTS score was correlated with the total foveal thickness (r = 0.43, p = 0.004), the height of serous retinal detachment (r = 0.31, p = 0.047), and the maximum outer retinal thickness (r = 0.36, p = 0.020). One month after treatment, both the inner and outer retinal thickness substantially decreased. However, metamorphopsia persisted in 26 (89.7%) of 29 eyes. The posttreatment M-CHARTS score was not correlated with any posttreatment morphological parameters. However, the posttreatment M-CHARTS score was weakly correlated with the baseline total foveal thickness (r = 0.35. p = 0.024) and closely correlated with the baseline M-CHARTS score (r = 0.78, p < 0.001). Conclusions Metamorphopsia associated with acute BRVO was quantified using M-CHARTS. Initial microstructural changes in the outer retina from acute BRVO may primarily account for the metamorphopsia. PMID:27123642

  2. Endovascular Treatment of Venous Occlusive Disease

    PubMed Central

    2008-01-01

    Endovascular treatment of acute and chronic iliac vein occlusions has proven to be safe and effective. Recanalization of chronic occlusions with balloon angioplasty and stenting can re-establish normal venous flow in the iliac veins and the IVC and relieve symptoms in the majority of treated patients. CDT with recanalization and stenting of underlying chronically obstructed iliofemoral segments is becoming the treatment of choice for patients with acute iliofemoral thrombosis, as anticoagulation and compression therapy alone are not satisfactory in preventing PTS. The new treatment modalities offer stimulating options for a patient group that is not adequately treated, neither by medical nor open surgical therapy. The substantial effort and additional costs of endovascular treatment appear to be justified by the encouraging mid-term results both for patients with acute and chronic occlusive iliofemoral disease. However, multi-center randomized prospective studies are required to further validate the role of these techniques. PMID:23555345

  3. [Retinal vein occlusion: an interdisciplinary approach].

    PubMed

    Hatz, Katja; Martinez, Maria

    2016-01-01

    Retinal vein occlusion provide a common cause of significant visual reduction but also late ocular complications. The medical care of these patients pursue two goals: On the one hand vision threatening complications need to be identified and treated, and on the other hand treatable risk factors are need to be identified and treated. This paper summarizes the common ophthalmological therapeutic approaches as well as recommended medical evaluations carried out by the general practitioner. This supports the interdisciplinary approach in evaluating and treating retinal vein occlusions by ophthalmologists and the general practitioners/specialist in internal medicine. PMID:26982647

  4. Occlusal Characteristics of the Primary Dentition Revisited.

    PubMed

    Alexander, Stanley A; Askari, Marjan; Lewis, Patricia

    2015-11-01

    The occlusal characteristics of the primary dentition of 130 children 3 to 6 years old were examined. Variables were the terminal plane relationship, primary canine occlusion, spacing, overjet and overbite relationships. The flush terminal plane was the most common finding. A Class I relationship of the primary canine occurred in 85% of the subjects. Spaced dentitions occurred 81% of the time, while the presence of primate spaces occurred in at least one of the four quadrants. The overjet relationship varied from +1 mm to 4 mm in all subjects, and the majority of children were considered to have a normal overbite. PMID:26749782

  5. Thrombotic Occlusion during Intravascular Ultrasonography-Guided Percutaneous Coronary Intervention of Stumpless Chronic Total Occlusion.

    PubMed

    Lee, Un Joo; Kim, Hyun Soo; Lee, Cheolhyun; Kim, Kwang-Yeol; Kim, Weon

    2014-12-01

    Percutaneous coronary intervention (PCI) of stumpless chronic total occlusion (CTO) lesions with a side branch stemming from the occlusion have a significantly lower treatment success rate because physicians cannot identify an accurate entry point with only conventional angiographic images. An intravascular ultrasonography (IVUS)-guided wiring technique might be useful for the penetration of stumpless CTO. We recently experienced thrombotic occlusion during an IVUS-guided stumpless CTO procedure. The cause of the thrombosis is not completely understood; the thrombosis may have been associated with the long use of the IVUS catheter. Special precautions should be taken to prevent thrombus in such cases. PMID:25568847

  6. Iterative learning control applied to a non-linear vortex panel model for improved aerodynamic load performance of wind turbines with smart rotors

    NASA Astrophysics Data System (ADS)

    Blackwell, Mark W.; Tutty, Owen R.; Rogers, Eric; Sandberg, Richard D.

    2016-01-01

    The inclusion of smart devices in wind turbine rotor blades could, in conjunction with collective and individual pitch control, improve the aerodynamic performance of the rotors. This is currently an active area of research with the primary objective of reducing the fatigue loads but mitigating the effects of extreme loads is also of interest. The aerodynamic loads on a wind turbine blade contain periodic and non-periodic components and one approach is to consider the application of iterative learning control algorithms. In this paper, the control design is based on a simple, in relative terms, computational fluid dynamics model that uses non-linear wake effects to represent flow past an airfoil. A representation for the actuator dynamics is included to undertake a detailed investigation into the level of control possible and on how performance can be effectively measured.

  7. Findings of pre-ELM structures through the observation of divertor heat load patterns at JET with applied n = 2 perturbation fields

    NASA Astrophysics Data System (ADS)

    Rack, M.; Sieglin, B.; Eich, T.; Pearson, J.; Liang, Y.; Balboa, I.; Jachmich, S.; Wingen, A.; Pamela, S. J. P.; EFDA Contributors, JET

    2014-07-01

    Resonant magnetic perturbation experiments at JET with the ITER-like wall have shown the formation of radially propagating pre-ELM structures in the heat flux profile on the outer divertor. These appear a few milliseconds before the major divertor heat load, caused by type-I edge-localized modes (ELMs). The formation of the pre-ELM structures is accompanied by an increase in the Dα emission. For some pronounced examples, the propagation appears to end at the positions where an increased heat load is seen during the ELM crash a few milliseconds later. These observations are presented and discussed along with a comparison of a thermoelectric edge currents model.

  8. 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

  9. Virtual occlusal definition for orthognathic surgery.

    PubMed

    Liu, X J; Li, Q Q; Zhang, Z; Li, T T; Xie, Z; Zhang, Y

    2016-03-01

    Computer-assisted surgical simulation is being used increasingly in orthognathic surgery. However, occlusal definition is still undertaken using model surgery with subsequent digitization via surface scanning or cone beam computed tomography. A software tool has been developed and a workflow set up in order to achieve a virtual occlusal definition. The results of a validation study carried out on 60 models of normal occlusion are presented. Inter- and intra-user correlation tests were used to investigate the reproducibility of the manual setting point procedure. The errors between the virtually set positions (test) and the digitized manually set positions (gold standard) were compared. The consistency in virtual set positions performed by three individual users was investigated by one way analysis of variance test. Inter- and intra-observer correlation coefficients for manual setting points were all greater than 0.95. Overall, the median error between the test and the gold standard positions was 1.06mm. Errors did not differ among teeth (F=0.371, P>0.05). The errors were not significantly different from 1mm (P>0.05). There were no significant differences in the errors made by the three independent users (P>0.05). In conclusion, this workflow for virtual occlusal definition was found to be reliable and accurate. PMID:26701322

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

    PubMed Central

    Jung, Jaehoon; Yoon, Inhye; Paik, Joonki

    2016-01-01

    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. PMID:27347978

  11. Chronic common femoral vein occlusion secondary to endometriosis

    PubMed Central

    Ju, Mila H.; Keldahl, Mark L.; Rodriguez, Heron E.

    2016-01-01

    Venous occlusion is sometimes caused by external compression due to adjacent masses. Endometriosis, the presence of functioning endometrial tissue outside the uterine cavity, is a rare cause of venous occlusion. We report a case of chronic common femoral vein occlusion due to endomctrioma causing severe leg edema and groin pain that was treated with resection and venous bypass. PMID:26993188

  12. 21 CFR 880.5950 - Umbilical occlusion device.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Umbilical occlusion device. 880.5950 Section 880... Devices § 880.5950 Umbilical occlusion device. (a) Identification. An umbilical occlusion device is a clip, tie, tape, or other article used to close the blood vessels in the umbilical cord of a newborn...

  13. 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... Devices § 880.5950 Umbilical occlusion device. (a) Identification. An umbilical occlusion device is a clip, tie, tape, or other article used to close the blood vessels in the umbilical cord of a newborn...

  14. 21 CFR 880.5950 - Umbilical occlusion device.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Umbilical occlusion device. 880.5950 Section 880... Devices § 880.5950 Umbilical occlusion device. (a) Identification. An umbilical occlusion device is a clip, tie, tape, or other article used to close the blood vessels in the umbilical cord of a newborn...

  15. 21 CFR 880.5950 - Umbilical occlusion device.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Umbilical occlusion device. 880.5950 Section 880... Devices § 880.5950 Umbilical occlusion device. (a) Identification. An umbilical occlusion device is a clip, tie, tape, or other article used to close the blood vessels in the umbilical cord of a newborn...

  16. 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... Devices § 880.5950 Umbilical occlusion device. (a) Identification. An umbilical occlusion device is a clip, tie, tape, or other article used to close the blood vessels in the umbilical cord of a newborn...

  17. The role of "rescue saccades" in tracking objects through occlusions.

    PubMed

    Zelinsky, Gregory J; Todor, Andrei

    2010-01-01

    We hypothesize that our ability to track objects through occlusions is mediated by timely assistance from gaze in the form of "rescue saccades"-eye movements to tracked objects that are in danger of being lost due to impending occlusion. Observers tracked 2-4 target sharks (out of 9) for 20 s as they swam through a rendered 3D underwater scene. Targets were either allowed to enter into occlusions (occlusion trials) or not (no occlusion trials). Tracking accuracy with 2-3 targets was ≥ 92% regardless of target occlusion but dropped to 74% on occlusion trials with four targets (no occlusion trials remained accurate; 83%). This pattern was mirrored in the frequency of rescue saccades. Rescue saccades accompanied approximatlely 50% of the Track 2-3 target occlusions, but only 34% of the Track 4 occlusions. Their frequency also decreased with increasing distance between a target and the nearest other object, suggesting that it is the potential for target confusion that summons a rescue saccade, not occlusion itself. These findings provide evidence for a tracking system that monitors for events that might cause track loss (e.g., occlusions) and requests help from the oculomotor system to resolve these momentary crises. As the number of crises increase with the number of targets, some requests for help go unsatisfied, resulting in degraded tracking. PMID:21191133

  18. 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...) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4020 Occlusive wound dressing. (a) Identification. An occlusive wound dressing is a nonresorbable, sterile or non-sterile...

  19. 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...) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4020 Occlusive wound dressing. (a) Identification. An occlusive wound dressing is a nonresorbable, sterile or non-sterile...

  20. 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...) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4020 Occlusive wound dressing. (a) Identification. An occlusive wound dressing is a nonresorbable, sterile or non-sterile...

  1. 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...) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4020 Occlusive wound dressing. (a) Identification. An occlusive wound dressing is a nonresorbable, sterile or non-sterile...

  2. 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...) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4020 Occlusive wound dressing. (a) Identification. An occlusive wound dressing is a nonresorbable, sterile or non-sterile...

  3. Venous sinus occlusive disease: MR findings

    SciTech Connect

    Yuh, W.T.C.; Simonson, T.M.; Tali, E.T.; Fisher, D.J. ); Wang, A.M. ); Koci, T.M. ); Simon, J.H. ); Jinkins, J.R. ); Tsai, Fong )

    1994-02-01

    To study MR patterns of venous sinus occlusive disease and to relate them to the underlying pathophysiology by comparing the appearance and pathophysiologic features of venous sinus occlusive disease with those of arterial ischemic disease. The clinical data and MR examinations of 26 patients with venous sinus occlusive disease were retrospectively reviewed with special attention to mass effect, hemorrhage, and T2-weighted image abnormalities as well as to abnormal parenchymal, venous, or arterial enhancement after intravenous gadopentetate dimeglumine administration. Follow-up studies when available were evaluated for atrophy, infraction, chronic mass effect, and hemorrhage. Mass effect was present in 25 of 26 patients. Eleven of the 26 had mass effect without abnormal signal on T2-weighted images. Fifteen patients had abnormal signal on T2-weighted images, but this was much less extensive than the degree of brain swelling in all cases. No patient showed abnormal parenchymal or arterial enhancement. Abnormal venous enhancement was seen in 10 of 13 patients who had contrast-enhanced studies. Intraparenchymal hemorrhage was seen in nine patients with high signal on T2-weighted images predominantly peripheral to the hematoma in eight. Three overall MR patterns were observed in acute sinus thrombosis: (1) mass effect without associated abnormal signal on T2-weighted images, (2) mass effect with associated abnormal signal on T2-weighted images and/or ventricular dilatation that may be reversible, and (3) intraparenchymal hematoma with surrounding edema. MR findings of venus sinus occlusive disease are different from those of arterial ischemia and may reflect different underlying pathophysiology. In venous sinus occlusive disease, the breakdown of the blood-brain barrier (vasogenic edema and abnormal parenchymal enhancement) does not always occur, and brain swelling can persist up to 2 years with or without abnormal signal on T2-weighted images. 34 refs., 5 figs.

  4. An investigation on the simultaneously recorded occlusion contact and surface electromyographic activity for patients with unilateral temporomandibular disorders pain.

    PubMed

    Li, Bao-Yong; Zhou, Li-Juan; Guo, Shao-Xiong; Zhang, Yuan; Lu, Lei; Wang, Mei-Qing

    2016-06-01

    The present study examined if unilateral pain from temporomandibular disorders (TMD) was associated with the occlusion contacts and surface electromyographic (SEMG) activities of jaw-closing muscles. Eleven patients with unilateral TMD pain and 20 healthy volunteers who all had Angle's Class-I occlusions were enrolled. The numbers and load distributions of the occlusion contacts and the SEMG activities of the anterior temporalis (TA) muscles and masseters muscles (MM) during maximal voluntary clenching (MVC) in the centric and eccentric positions were simultaneously recorded on both sides. The pain was not associated with occlusal contact numbers or load distributions. The SEMG activities of the pain-side TA and bilateral MM were lower during centric MVC compared with controls. The SEMG activities of the non-pain-side TA and the normalized SEMG activities of the bilateral TAs and MMs were higher during protrusive MVC (p<0.05). During pain-side MVC, the normalized SEMG activities of the working-side MM and balancing-side TA were higher than those of the controls. In conclusion, the TMD pain side was not associated with the occlusal contacts, but the patients with TMD had TA and MM SEMG activities during different tasks that differed from controls and that did not seem related to the pain side. PMID:26643794

  5. PS-OCT of occlusal and interproximal caries lesions viewed from occlusal surfaces

    NASA Astrophysics Data System (ADS)

    Ngaotheppitak, Patara; Darling, Cynthia L.; Fried, Daniel; Bush, Jeff; Bell, Steve

    2006-02-01

    Previous studies have demonstrated that Polarization Sensitive Optical Coherence Tomography (PS-OCT) can be used to image early dental caries. The primary objective of this study was to compare the measured reflectivity of natural occlusal caries lesions with the relative mineral loss measured using digital microradiography. There was excellent agreement between the increase in the integrated reflectivity in the perpendicular polarization axis of the PS-OCT system and the increase in the integrated mineral loss or lesion severity for occlusal lesions. Therefore, PS-OCT is ideally suited to image natural caries lesions in the important occlusal surfaces for the assessment of the lesion severity and activity. A secondary objective was to compare the performance of a new autocorrelator-based PS-OCT system employing a novel polarization-switching probe with our polarization-maintaining fiber based PS-OCT system, both operating at 1310-nm. The new PS-OCT system produced clean images with no artifacts and achieved high penetration depth. Yet a third objective was to determine if interproximal lesions can be imaged from the occlusal surface (from above) since interproximal lesions may only be accessible in vivo from buccal or lingual surfaces or from the occlusal surface. Simulated and natural interproximal caries lesions were imaged from the occlusal surfaces as long as there was no intervening dentin.

  6. On crack growth in molar teeth from contact on the inclined occlusal surface.

    PubMed

    Chai, Herzl

    2015-04-01

    Extracted human molar teeth are indented by hard balls laid at the central fossa, sectioned, and their interior examined for damage. Contact on the fissured enamel coat generally occurs on three distinct spots. The main forms of damage are radial cracks growing from the DEJ to the occlusal surface and median radial and cylindrical cracks growing from a contact spot to the DEJ. For large balls failure by edge chipping near a cusp apex may occur. The median cracks tend to run unstably to the DEJ upon reaching the middle part of the enamel coat. The corresponding load, PFM, and the load needed to initiate radial cracks at the DEJ, PFR, are taken to signal crown failure. The mean values of PFM and PFR are on the order of 1000N. A conical bilayer model defined by thickness d, inclination angle θ, failure stress σF and toughness KC of the enamel coat is developed to assess crown failure. The analytical predictions for PFR and PFM agree well with the tests. The results indicate that enamel thickness is so designed as to ensure that PFR and PFM just exceed the maximum bite force under normal conditions while the choice of θ seems to reflect a compromise between needs to resist crown failure and break hard food particles. Both PFR and PFM are greatly reduced with reducing d, which points to the danger posed by tooth wear. The analytical expressions for PFR and PFM may also apply to other multi-cusp mammalian or prosthetic molar crowns. Cone cracking, suppressed in the anisotropic tooth enamel, may be an important failure mode in prosthetic crowns. PMID:25621848

  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 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

  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 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

  9. Occlusal Interferences: How Can This Concept Influence The Clinical Practice?

    PubMed Central

    Lima, Adriano Fonseca; Cavalcanti, Andrea Nóbrega; Martins, Luis Roberto Marcondes; Marchi, Giselle Maria

    2010-01-01

    This brief review discusses the role of occlusal interferences on the development and progression of temporomandibular dysfunction (TMD) and postural disorders. The eligible literature is described and critically presented to demonstrate that occlusal interferences are an important factor in the risk of TMD. Several studies have demonstrated through their findings that the use of occlusal adjustments, whether or not associated with restorative procedures, might avoid the development of articular problems in vulnerable patients. The occlusal interferences caused by restorative procedures or orthodontic treatment can cause TMDs in susceptible patients, and occlusal adjustments can be an alternative in the treatment of these TMDs. PMID:20922171

  10. Dental Occlusal Changes Induce Motor Cortex Neuroplasticity.

    PubMed

    Avivi-Arber, L; Lee, J-C; Sessle, B J

    2015-12-01

    Modification to the dental occlusion may alter oral sensorimotor functions. Restorative treatments aim to restore sensorimotor functions; however, it is unclear why some patients fail to adapt to the restoration and remain with sensorimotor complaints. The face primary motor cortex (face-M1) is involved in the generation and control of orofacial movements. Altered sensory inputs or motor function can induce face-M1 neuroplasticity. We took advantage of the continuous eruption of the incisors in Sprague-Dawley rats and used intracortical microstimulation (ICMS) to map the jaw and tongue motor representations in face-M1. Specifically, we tested the hypothesis that multiple trimming of the right mandibular incisor, to keep it out of occlusal contacts for 7 d, and subsequent incisor eruption and restoration of occlusal contacts, can alter the ICMS-defined features of jaw and tongue motor representations (i.e., neuroplasticity). On days 1, 3, 5, and 7, the trim and trim-recovered groups had 1 to 2 mm of incisal trimming of the incisor; a sham trim group had buccal surface trimming with no occlusal changes; and a naive group had no treatment. Systematic mapping was performed on day 8 in the naive, trim, and sham trim groups and on day 14 in the trim-recovered group. In the trim group, the tongue onset latency was shorter in the left face-M1 than in the right face-M1 (P < .001). In the trim-recovered group, the number of tongue sites and jaw/tongue overlapping sites was greater in the left face-M1 than in the right face-M1 (P = 0.0032, 0.0016, respectively), and the center of gravity was deeper in the left than in the right face-M1 (P = 0.026). Therefore, incisor trimming and subsequent restoration of occlusal contacts induced face-M1 neuroplasticity, reflected in significant disparities between the left and right face-M1 in some ICMS-defined features of the tongue motor representations. Such neuroplasticity may reflect or contribute to subjects' ability to adapt their

  11. Concepts of occlusion in prosthodontics: A literature review, part I

    PubMed Central

    Rangarajan, V.; Gajapathi, B.; Yogesh, P. B.; Ibrahim, M. Mohamed; Kumar, R. Ganesh; Karthik, Prasanna

    2015-01-01

    Occlusion and its relationship to the function of the stomatognathic system have been widely studied in dentistry since many decades. This series of articles describe about occlusion in the complete denture, fixed partial denture, and implants. Part I and II of this articles series describe concepts and philosophies of occlusion in complete denture. So far, available research has not concluded a superior tooth form or occlusal scheme to satisfy the requirements of completely edentulous patients with respect to comfort, mastication, phonetics, and esthetics. Since then, several balanced and nonbalanced articulation concepts were proposed in the literature. A balanced articulation appears to be most appropriate because of tooth contacts observed during nonfunctional activities of patients. This article discusses about evolution of different concepts of occlusion and occlusal schemes in complete denture occlusion. PMID:26929513

  12. Plethysmography without venous occlusion for measuring forearm blood flow: comparison with venous occlusive method.

    PubMed

    Chuah, Seong S; Woolfson, Peter I; Pullan, Brian R; Lewis, Philip S

    2004-09-01

    Limb blood flow is widely used as an indicator of the human vascular properties. There are only few non-invasive methods for its measurement such as venous occlusion plethysmography. However, several authors have questioned its validity. The problems appear to be related to the process of venous occlusion. We developed two methods to measure forearm blood flow by plethysmography without venous occlusion in combination with Doppler velocimetry (without imaging). Method 1: the gradient of a tangent drawn on the latter part of the down stroke of the plethysmographic volume pulse is an approximation of venous blood flow in the absence of diastolic blood flow. At equilibrium, it equals the average arterial flow in a cardiac cycle. The Doppler velocity waveform recorded simultaneously allows improvement of this approximation when there is diastolic blood flow. Method 2: the volume pulse detected by a plethysmograph calibrated in absolute volume is used to calibrate the velocity waveform recorded simultaneously to produce an approximation of arterial volumetric flow waveform. Bland-Altman analysis shows both methods have good correlation and agreement with venous occlusion plethysmography at rest. Method 1: mean difference (blood flow measured by venous occlusion minus calculated flow) = 0.10 ml/pulse (+/-0.18), limits of agreement = -0.41 and 0.61 ml/pulse. Method 2: mean difference = -0.041 ml/pulse (+/-0.15), limits of agreement = -0.45 and 0.37 ml/pulse. During hyperaemia, venous occlusion plethysmography grossly underestimated relative to the new methods. The new methods are not dependent on venous occlusion and produce consistent results with or without hyperaemia. PMID:15383087

  13. 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

  14. 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. PMID:24521751

  15. Photometric Ambient Occlusion for Intrinsic Image Decomposition.

    PubMed

    Hauagge, Daniel; Wehrwein, Scott; Bala, Kavita; Snavely, Noah

    2016-04-01

    We present a method for computing ambient occlusion (AO) for a stack of images of a Lambertian scene from a fixed viewpoint. Ambient occlusion, a concept common in computer graphics, characterizes the local visibility at a point: it approximates how much light can reach that point from different directions without getting blocked by other geometry. While AO has received surprisingly little attention in vision, we show that it can be approximated using simple, per-pixel statistics over image stacks, based on a simplified image formation model. We use our derived AO measure to compute reflectance and illumination for objects without relying on additional smoothness priors, and demonstrate state-of-the art performance on the MIT Intrinsic Images benchmark. We also demonstrate our method on several synthetic and real scenes, including 3D printed objects with known ground truth geometry. PMID:26959670

  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. [TMJ morphological changes in abnormal occlusion].

    PubMed

    Volkov, S I; Bazhenov, D V; Semkin, V A; Bogdanov, A O

    2013-01-01

    TMJ dysfunction is one of the most common diseases among all disorders of the maxillofacial region. Any abnormality in synchrony or amplitude of motion of the TMJ results in the malposition of the articular disc. Researchers and clinicians were always interested in topographic anatomy of the TMJ. There is currently no consensus on matters relating to changes in anatomical features of the TMJ by occlusal disturbances. PMID:23715443

  18. Human skin penetration and local effects of topical nano zinc oxide after occlusion and barrier impairment.

    PubMed

    Leite-Silva, V R; Sanchez, W Y; Studier, H; Liu, D C; Mohammed, Y H; Holmes, A M; Ryan, E M; Haridass, I N; Chandrasekaran, N C; Becker, W; Grice, J E; Benson, H A E; Roberts, M S

    2016-07-01

    Public health concerns continue to exist over the safety of zinc oxide nanoparticles that are commonly used in sunscreen formulations. In this work, we assessed the effects of two conditions which may be encountered in everyday sunscreen use, occlusion and a compromised skin barrier, on the penetration and local toxicity of two topically applied zinc oxide nanoparticle products. Caprylic/capric triglyceride (CCT) suspensions of commercially used zinc oxide nanoparticles, either uncoated or with a silane coating, were applied to intact and barrier impaired skin of volunteers, without and with occlusion for a period of six hours. The exposure time was chosen to simulate normal in-use conditions. Multiphoton tomography with fluorescence lifetime imaging was used to noninvasively assess zinc oxide penetration and cellular metabolic changes that could be indicative of toxicity. We found that zinc oxide nanoparticles did not penetrate into the viable epidermis of intact or barrier impaired skin of volunteers, without or with occlusion. We also observed no apparent toxicity in the viable epidermis below the application sites. These findings were validated by ex vivo human skin studies in which zinc penetration was assessed by multiphoton tomography with fluorescence lifetime imaging as well as Zinpyr-1 staining and toxicity was assessed by MTS assays in zinc oxide treated skin cryosections. In conclusion, applications of zinc oxide nanoparticles under occlusive in-use conditions to volunteers are not associated with any measurable zinc oxide penetration into, or local toxicity in the viable epidermis below the application site. PMID:27131753

  19. [Interception in the primary dentition: mastication and neuro-occlusal rehabilitation].

    PubMed

    Limme, M

    2006-03-01

    After evoking the characteristics of masticatory movements, their control and their adaptability, a review of the literature illustrates how the masticatory work and its variations can influence the dentoalveolar, as well as the maxillary growth, by adapting the morphological structures to the functional context. The conceptions of Planas, and especially his "neuro-occlusal rehabilitation", are widely explained: unilateral alternate mastication, "Planas' Functional Masticatory Angles (PFMA) and the vertical dimension, the "atrophies" of maxillary development resulting from reduced mastication, the "dominant unilateral mastication syndrome" and, of course, all the original treatments introduced by Planas. These specific orthodontic treatments can be applied as interceptive procedure as early as during the deciduous dentition. The selective occlusal grinding, implemented to reduce and balance the "PFMA", and the expansion devices using "running track plates" are described in concepts and clinical uses. Planas' Class II treatments of Class II, also using "direct occlusal bonded tracks" and several mandibular propulsion auxiliaries are explained as well as the early treatments of lateral cross-bite and the use of the "Equiplan". Mastication, the first of the functions assigned and carried out by the masticatory apparatus, is a genuine "functional matrix" able to stimulate the growth of the dental arches and of the maxillaries. When perfectly understood and applied, the "neuro-occlusal rehabilitation" according to Planas allows to restore a functional balance for the masticatory apparatus from an early age, and subsequently, reorientates growth to a morphological normalization. PMID:16708660

  20. Crossing Total Occlusions: Navigating Towards Recanalization.

    PubMed

    Sakes, Aimée; Regar, Evelyn; Dankelman, Jenny; Breedveld, Paul

    2016-06-01

    Chronic total occlusions (CTOs) represent the "last frontier" of percutaneous interventions. The main technical challenges lies in crossing the guidewire into the distal true lumen, which is primarily due to three problems: device buckling during initial puncture, inadequate visualization, and the inability to actively navigate through the CTO. To improve the success rate and to identify future research pathways, this study systematically reviews the state-of-the-art of all existing and invented devices for crossing occlusions. The literature search was executed in the databases of Scopus and Espacenet using medical and instrument-related keyword combinations. The search yielded over 840 patents and 69 articles. After scanning for relevancy, 45 patents and 16 articles were included. The identified crossing devices were subdivided based on the determinant for the crossing path through the occlusion, which is either the device (straight and angled crossing), the environment (least resistance, tissue selective, centerline, and subintimal crossing) or the user (directly steered and sensor enhanced crossing). It was found that each crossing path is characterized by specific advantages and disadvantages. For a future crossing device, a combination of crossing paths is suggested were the interventionist is able to exert high forces on the CTO (as seen in the device approach) and actively steer through the CTO (user: directly steered crossing) aided by intravascular imaging (user: sensor enhanced crossing) or an intrinsically safe device following the centerline or path of least resistance (environment: centerline crossing or least resistance crossing) to reach the distal true lumen. PMID:26831298

  1. 14 CFR 25.509 - Towing loads.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... wheel to which the load is applied. Enough airplane inertia to achieve equilibrium must be applied. (ii) The loads must be reacted by airplane inertia. (d) The prescribed towing loads are as follows:...

  2. 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

    2016-10-01

    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 20mgg(-1)) is sufficient for the rapid removal of high amount of MG dye in short time (3.99min). PMID:27318150

  3. Occlusion and weight change in a patient after esophagectomy: success derived from restoration of occlusal support.

    PubMed

    Yamanaka, Reiko; Soga, Yoshihiko; Minakuchi, Mami; Nawachi, Kumiko; Maruyama, Takayuki; Kuboki, Takuo; Morita, Manabu

    2013-01-01

    Occlusal support may be an important factor affecting nutritional support after major surgery. This report presents a patient who gained body weight after receiving a new prosthesis. The patient was an 82-year-old man with thoracic esophageal carcinoma. He did not have occlusal support because of multiple caries lesions. His body weight slowly increased after surgery, but almost stopped in the period of 54 to 68 days after surgery. After treatment with dentures (day 72 postsurgery), body weight gain was observed again, although his medical treatment had not changed. An appropriate prosthesis could contribute to perioperative nutrition support and may lead to earlier recovery after surgery. PMID:24179973

  4. 20(s)-ginsenoside Rg3-loaded magnetic human serum albumin nanospheres applied to HeLa cervical cancer cells in vitro.

    PubMed

    Yang, Rui; Chen, Daozhen; Li, Mengfei; Miao, Fengqin; Liu, Peidang; Tang, Qiusha

    2014-01-01

    20(s)-ginsenoside Rg3 is extracted from traditional Chinese medicine, red ginseng. However, due to its poor aqueous solubility and low oral bioavailability, the use of 20(s)-Rg3 is limited. This study aimed to explore a method of preparing nano-sized 20(s)-ginsenoside Rg3 particle named 20(s)-ginsenoside Rg3-loaded magnetic human serum albumin nanospheres (20(s)-Rg3/HSAMNP) to change dosage form to improve its aqueous solubility and bioavailability. 20(s)-Rg3/HSAMNP were prepared by the desolvation-crosslinking method. The character of 20(s)-Rg3/HSAMNP was detected. An antiproliferative effect and cell apoptosis rates of 20(s)-Rg3/HSAMNP on human cervical cancer cells were determined by the MTT assay and flow cytometry, respectively. TEM analysis showed that 20(s)-Rg3/HSAMNP were approximately spherical and uniform in size. Thermodynamic testing showed that the corresponding magnetic fluid of a specific concentration rosed to a steady temperature of 42-65○C. Iron content was approximately 3 mg/mL. Drug encapsulation efficiency was approximately 70%. The potential of 20(s)-Rg3/HSAMNP combined with magnetic hyperthermia therapy to inhibit cell growth and induce apoptosis was much more prominent than that of the other groups. A new dosage form of 20(s)-Rg3 was prepared, which effectively induced apoptosis in HeLa cervical cancer cells in vitro when combined with hyperthermia. PMID:25226895

  5. Dental occlusion modifies gaze and posture stabilization in human subjects.

    PubMed

    Gangloff, P; Louis, J P; Perrin, P P

    2000-11-01

    Repercussion of dental occlusion was tested upon postural and gaze stabilization, the latter with a visuo-motor task evaluated by shooting performances. Eighteen permit holders shooters and 18 controls were enrolled in this study. Postural control was evaluated in both groups according to four mandibular positions imposed by interocclusal splints: (i) intercuspal occlusion (IO), (ii) centric relation (CR), (iii) physiological side lateral occlusion and (iv) controlateral occlusion, in order to appreciate the impact of the splints upon orthostatism. Postural control and gaze stabilization quality decreased, from the best to the worst, with splints in CR, IO and lateral occlusion. In shooters, the improvement in postural control was parallel to superior shooting performance. A repercussion of dental occlusion upon proprioception and visual stabilization is suggested by these data. PMID:11036196

  6. Dental Occlusion Influences the Standing Balance on an Unstable Platform.

    PubMed

    Julià-Sánchez, Sonia; Álvarez-Herms, Jesús; Gatterer, Hannes; Burtscher, Martin; Pagès, Teresa; Viscor, Ginés

    2015-10-01

    Contradictory results are still reported on the influence of dental occlusion on the balance control. We attempted to determine whether there are differences in balance between opposed dental occlusion (Intercuspal position (ICP)/"Cotton rolls" mandibular position [CR]) for two extreme levels of stability (stable/ unstable). Twenty-five subjects were monitored under both dental occlusion and level of stability conditions using an unstable platform Balance System SD. The resulting stability index suggests that body balance is significantly better when dental occlusion is set in CR (p < .001) in unstable but not in stable conditions. Occlusal traits significantly influencing postural control were Angle Class (p < .001), crowding (p = .006), midline deviation (p < .001), crossbite (p < .001), anterior open bite (p = .05), and overjet (p = .01). It could be concluded that the sensory information linked to the dental occlusion for the balance control comes strongly into effect in unstable conditions. PMID:25674772

  7. [Gdansk combined crown with occlusal rest. 1. Clinical and laboratory preparation of combined crown with occlusal rest on the basis of cast crown].

    PubMed

    Tejchman, H; Czerwińska, W

    1990-01-01

    The combined crown used since many years in the Prosthetic Laboratory, Institute of Stomatology, Medical Academy in Gdańsk contains an occlusal rest basis of a cast crown (the metal part is of a gold alloy or chromium-nickel steel, with veneer of acrylateor Colorstat) provides, owing to a special preparation of the abutment tooth and laboratory procedure, full stabilization of the crown, protection of parodontium and good maintenance of the veneer which plays a cosmetic role in this type of crown. The combined crowns with occlusal rest are particularly suitable for supporting bridgeworks. They may be applied onto devitalized or live teeth since they require less extensive grinding of teeth. PMID:2103019

  8. Arterial gas occlusions in operating heat pipes

    NASA Technical Reports Server (NTRS)

    Saaski, E. W.

    1975-01-01

    The effect of noncondensable gases on high performance arterial heat pipes has been investigated both analytically and experimentally. Models have been generated which characterize the dissolution of gases in condensate and the diffusional loss of dissolved gases from condensate in arterial flow. These processes, and others, have been used to postulate stability criteria for arterial heat pipes. Experimental observations of gas occlusions were made using a stainless steel heat pipe equipped with viewing ports, and the working fluids methanol and ammonia with the gas additives helium, argon, and xenon. Observations were related to gas transport models.

  9. Collagen plug occlusion of Molteno tube shunts.

    PubMed

    Stewart, W; Feldman, R M; Gross, R L

    1993-01-01

    We report five patients in whom collagen lacrimal plugs were used to temporarily occlude the lumen of Molteno shunts to prevent early postoperative hypotony. Only one eye, with a double plate, developed hypotony and a flat anterior chamber that required reformation. However, in three patients, the collagen plugs did not dissolve and had to be removed surgically to lower the intraocular pressure. Although the semipermeability of collagen is desirable, its unpredictable degradation renders it unsuitable for temporary occlusion of tube shunts. Other biodegradable materials may be more appropriate for this purpose. PMID:8446334

  10. Trigeminal trophic syndrome treated with thermoplastic occlusion.

    PubMed

    Kurien, Anil M; Damian, Diona L; Moloney, Fergal J

    2011-02-01

    A 72-year-old man with a history of thrombotic CVA causing lateral medullary infarction presented with non-healing ulcers of the right side of the face of 5 months' duration. After extensive investigations, a diagnosis of trigeminal trophic syndrome was made. The ulcers progressed relentlessly despite amitriptyline and gabapentin, and he was treated with a combination of carbamazepine and thermoplastic mask occlusion of the right side of his face. Over the next 10 weeks the shallower facial ulcers began to diminish in depth and diameter, and the deeper ulcers stopped progressing. Although the patient showed early signs of healing, he died because of complications from the CVA. PMID:21332680

  11. Evaluation of a new liquid occlusive dressing for excisional wounds.

    PubMed

    Singer, Adam J; Nable, Maria; Cameau, Paul; Singer, Daniel D; McClain, Steve A

    2003-01-01

    We evaluated a novel octylcyanoacrylate-based liquid occlusive dressing for partial-thickness wounds. One hundred and fifteen standardized wounds were created with an electric dermatome set at a depth of 600 micro on the flanks of three pigs and randomly treated with liquid occlusive dressing, a hydrocolloid dressing, or gauze. In one pig, wounds were swabbed with Staphylococcus aureus. Biopsies were taken after 4, 5, 6, and 21 days. Hemostasis was obtained in all wounds treated with the liquid occlusive. The percent reepithelialization of wounds treated with the liquid occlusive and hydrocolloid dressings were significantly greater at days 4 and 5 than control wounds (78% and 82% vs. 40%, p < 0.001 and 99% and 100% vs. 72%, p < 0.001, respectively). None of the liquid occlusive-treated wounds challenged with bacteria became infected. Foreign body reactions were least common in wounds treated with the liquid occlusive (p < 0.001). Scar depth was less for liquid occlusive- and hydrocolloid-treated wounds than controls (285 micro and 303 micro vs. 490 micro, p < 0.001). We conclude that excisional wounds treated with the liquid occlusive dressing reepithelialize as quickly as hydrocolloid-treated wounds. The liquid occlusive dressing is an effective microbial barrier and hemostatic agent resulting in fewer foreign body reactions than hydrocolloid-treated wounds or controls. PMID:12753599

  12. Depth discrimination from occlusions in 3D clutter.

    PubMed

    Langer, Michael S; Zheng, Haomin; Rezvankhah, Shayan

    2016-09-01

    Objects such as trees, shrubs, and tall grass consist of thousands of small surfaces that are distributed over a three-dimensional (3D) volume. To perceive the depth of surfaces within 3D clutter, a visual system can use binocular stereo and motion parallax. However, such parallax cues are less reliable in 3D clutter because surfaces tend to be partly occluded. Occlusions provide depth information, but it is unknown whether visual systems use occlusion cues to aid depth perception in 3D clutter, as previous studies have addressed occlusions for simple scene geometries only. Here, we present a set of depth discrimination experiments that examine depth from occlusion cues in 3D clutter, and how these cues interact with stereo and motion parallax. We identify two probabilistic occlusion cues. The first is based on the fraction of an object that is visible. The second is based on the depth range of the occluders. We show that human observers use both of these occlusion cues. We also define ideal observers that are based on these occlusion cues. Human observer performance is close to ideal using the visibility cue but far from ideal using the range cue. A key reason for the latter is that the range cue depends on depth estimation of the clutter itself which is unreliable. Our results provide new fundamental constraints on the depth information that is available from occlusions in 3D clutter, and how the occlusion cues are combined with binocular stereo and motion parallax cues. PMID:27618514

  13. [Research Advances in Baculovirus Occlusion-derived Virions].

    PubMed

    Zhu, Shimao; Li, Hui

    2016-01-01

    Baculoviruses are a family of arthropod-specific viruses that produce two morphologically distinct types of virions (budded and occlusion-derived) in their lifecycle. Baculoviruses establish infection in the midgut of their host via the oral route: occlusion-derived virions have pivotal roles in these processes. This review summarizes the basic characteristics of baculoviruses, and discusses the composition and classification of baculovirus occlusion-derived virions. The latter focuses mainly on the evolution and role of multiple occlusion-derived virions in the lifecycle of baculoviruses. These achievements should aid understanding the evolution and infection mechanisms of baculoviruses. PMID:27295890

  14. Meningioma and occlusive vasculopathy: coexisting complications of past extracranial radiation

    SciTech Connect

    Montanera, W.; Chui, M.; Hudson, A.

    1985-07-01

    Two cases are reported in which a meningioma and occlusion of the internal carotid artery with development of transdural collateral circulation coexisted following extracranial radiation in childhood.

  15. In vitro evaluation of marginal and internal adaptation after occlusal stressing of indirect class II composite restorations with different resinous bases and interface treatments. "Post-fatigue adaptation of indirect composite restorations".

    PubMed

    Rocca, Giovanni Tommaso; Gregor, Ladislav; Sandoval, Maria Jose; Krejci, Ivo; Dietschi, Didier

    2012-10-01

    The present study evaluated the influence of different composite bases and surface treatments on marginal and internal adaptation of class II indirect composite restorations, after simulated occlusal loading. Thirty-two class II inlay cavities were prepared on human third molars, with margins located in cementum. A 1-mm composite base extending up to the cervical margins was applied on all dentin surfaces in the experimental groups; impressions were made and composite inlays fabricated. The following experimental conditions were tested: no liner (control group), flowable composite treated with soft air abrasion (experiment 1), flowable composite sandblasted (experiment 2) and restorative composite sandblasted (experiment 3). All specimens were submitted to 1,000,000 cycles with a 100-N eccentric load. Tooth-restoration margins were analysed semi-quantitatively by scanning electron microscopy before and after loading; internal adaptation was also evaluated after test completion. The percentage of perfect adaptation in enamel was 79.5% to 92.7% before loading and 73.3% to 81.9% after loading. Perfect adaptation to dentin was reduced before loading (54.8% to 77.6%) and after loading (41.9% to 63%), but no difference was found among groups for pre- and post-loading conditions. No debonding occurred between the base and composite luting. A significant, negative influence of cyclic loading was observed. The results of the present study support the use of flowable or restorative composites as base/liner underneath large class II restorations. Soft air abrasion represents a potential alternative to airborne particle abrasion for treating cavities before cementation. The application of a composite base underneath indirect composite restorations represents a feasible non-invasive alternative to surgical crown lengthening to relocate cavity margins from an intra-crevicular to supra-gingival position. PMID:22065245

  16. 14 CFR 23.509 - Towing loads.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... reaction must be applied at the axle of the wheel to which the load is applied. Enough airplane inertia to achieve equilibrium must be applied. (ii) The loads must be reacted by airplane inertia. (d)...

  17. 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

  18. 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.

  19. Smile line and occlusion: An epidemiological study

    PubMed Central

    Harati, Mahsa; Mostofi, Shahbaz Naser; Jalalian, Ezzatollah; Rezvani, Gholamreza

    2013-01-01

    Background: The purpose of the present study was to discuss some new concepts of the desirable characteristics of smile tooth display. Due to the increasing application of cosmetic dental treatments, there is an increasing need for better understanding of the esthetic principles. Materials and Methods: In the present descriptive study, with 212 participants, included were patients with no history of orthodontic treatment, loss or prosthetic replacement of anterior teeth, extracted teeth, lips with asymmetry or a history of trauma. Chi-square test was used to determine possible significances in the relation of smile line to Angle occlusion class, overbite and overjet and arch form. A P level of <0.05 was set as to be significant. Results: Chi-square test indicated that there was a significant difference between the smile design and overbite, overjet and gender but no statistically significant association was found between the smile design and crossbite, molar Angle classification and arch form. Conclusion: Within the limitations of such studies, it might be concluded that there is a significant and important relation between some occlusal parameters and smile design, which must be considered. PMID:24379858

  20. Recurrent syncope after left atrial appendage occlusion.

    PubMed

    Cruz-Gonzalez, Ignacio; Perez-Rivera, Jose-Angel; Bethencourt, Armando

    2015-02-01

    We present the case of a 72-year-old woman with permanent atrial fibrillation and contraindication to long-term oral anticoagulant therapy who underwent left atrial appendage (LAA) occlusion. A 24-mm Amplatzer Cardiac Plug (St Jude Medical) device was deployed. The inferior part of the external disc of the device appeared to be over the posterior leaflet of the mitral valve but no significant mitral stenosis or mitral regurgitation was detected before deployment. After the procedure the patient suffered several syncopes when she tried to stand up. A transesophageal echocardiography (TEE) was performed and no significant differences on the device position were detected, it was not possible to perform the TEE in a stand-up position due to the patient symptoms (hypotension, tachycardia, dizziness, and loss of consciousness). After discussion with the surgical team, surgical removal of the device and surgical exclusion of LAA was performed. The symptoms disappeared and the patient was discharged. In the best of our knowledge, this is the first time that recurrent syncope has been described as a complication of LAA occlusion. PMID:25044597

  1. Anthropology, tooth wear, and occlusion ab origine.

    PubMed

    Young, W G

    1998-11-01

    The purpose of this essay is to emphasize that anthropology, the study of man in his environments, is a potent tool for scientific discovery and inspiration in dental science. It attempts to capture flashes of creative anthropological insight which have illuminated studies of tooth wear and occlusion in the past. While it documents contributions, understandings, and misunderstandings from Australian and New Zealand dentists, it is not a hagiography. The real saint of this essay is the Australian aborigine. For when men and women are understood in their environments, much is learned from them which challenges preconceptions of our dental science culture. The essay concludes that new, contemporary Australian culture needs to be studied by anthropological approaches if we are to understand how dental erosion is exacerbating tooth wear and damaging the occlusions of contemporary Australians. Much remains to be discovered about contemporary lifestyles, habits, and diets that lead to dental erosion, the principal cause of contemporary tooth wear in this part of the world. PMID:9823723

  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. PMID:25585145

  3. Dental occlusion: modern concepts and their application in implant prosthodontics.

    PubMed

    Carlsson, Gunnar E

    2009-01-01

    The aim of this article was to review the literature on various aspects of occlusion related to implant prosthodontics, using PubMed and the Cochrane library. Even if the number of studies on implants and prosthodontics is very large, no randomized controlled trials or Cochrane reviews were found on the possible influence of occlusal design or characteristics of occlusion on treatment outcome. Therefore, studies and articles of a lower evidence level were accepted as the main part of the review. The widely spread opinion that implants are superior to natural teeth was refuted by two recent consensus conferences, which concluded that the long-term outcome of implant restorations is not better than that of natural teeth. No controlled studies on the optimal features of a harmonious natural and/or restored occlusion, including implant prostheses, were found. Nor was there any evidence that more sophisticated methods in jaw registration, e.g., using face-bows and adjustable articulators, compared with simpler methods, will yield better clinical prosthodontic results. This article discusses, among other things, concepts of occlusion of implant-supported restorations, occlusal material, cantilevers, and occlusal risk factors. Within the limitations of the review, it was concluded that many factors can influence implant failure and peri-implant bone loss but that little is known of the relative importance of such factors. Most probably, however, occlusal factors and details of occlusion are in general of minor importance for the outcome of implant restorations. Occlusion can be managed successfully by using simple methods for jaw registration and different occlusal concepts. PMID:19184293

  4. 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

  5. Intraluminal occlusion of the seminal duct by laser and Histoacryl: Two non-invasive alternatives for vasectomy

    NASA Astrophysics Data System (ADS)

    Freitag, B.; Sroka, R.; Koelle, S.; Becker, A. J.; Khoder, W.; Pongratz, T.; Stief, C. G.; Trottmann, M.

    2014-03-01

    Introduction and objective: Vasectomy is a well-established method in family control. Even though it is a safe and low risk operation, this surgery is invasive and difficult to reverse. Therefore the aim of this study was to investigate new non-invasive methods for occlusion of the seminal duct. Material and Methods: Seminal duct tissue was obtained from patients (n=30) suffering from prostate cancer and therefore undergoing prostatectomy. In a first set of experiments, the seminal duct was occluded by intraluminal application of Histoacryl® (Braun Aesculap AG, Tuttlingen, Germany). In a 2nd set of experiments, endoluminal laser induced occlusion was performed. Four different laser wavelengths (1940nm, 1470nm, 1064nm, 940nm) and different sets of laser parameters (e.g. power, exposure duration, fibre diameter, energy applied) were compared. Effectiveness of occlusion of the seminal duct was proven by post-treatment irrigation flow measurement, as well as by morphological analyses. To evaluate a potential damage of the surrounding tissue, external temperature was measured using a thermometer during laser application. Results: Intraluminal application of Histoacryl® induced an immediate and complete occlusion of the seminal duct. The underlying connective tissue maintained its functional integrity after this treatment. By laser light application to a Histoacryl® block, a hole could be created into the block thus indicating the possibility of recanalization. Treatment with laser energy resulted in shrinkage of the ductal lumen. The laser application generally caused necrosis in the epithelium and induced formation of vacuoles in the underlying connective tissue. As described for endoluminal varicose treatment, this distinct local reaction might result in an intense inflammation leading to a functional occlusion of the vas deferens. Conclusions: Both laser-induced occlusion and application of Histoacryl® are fast and simple techniques which may be able to achieve a

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

    PubMed

    Jaiswal, Poonam B; Davenport, Paul W

    2016-04-01

    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 that1) conscious rats exposed to ITTO will recruit the EI muscles with an increased electromyogram (EMG) activation and2) 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

  7. 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.

  8. The Effect of Occlusion on Motion Integration in Infants

    ERIC Educational Resources Information Center

    Otsuka, Yumiko; Konishi, Yukuo; Kanazawa, So; Yamaguchi, Masami K.

    2009-01-01

    Previous psychophysical studies have shown that the adult human visual system makes use of form information such as occlusion to determine whether to integrate or segregate local motion signals (J. McDermott, Y. Weiss, & E. H. Adelson, 2001). Using the displays developed by McDermott et al., these experiments examined whether occlusion and amodal…

  9. 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. PMID:26364588

  10. 21 CFR 870.2890 - Vessel occlusion transducer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Vessel occlusion transducer. 870.2890 Section 870... transducer. (a) Identification. A vessel occlusion transducer is a device used to provide an electrical..., sound, and ultrasonic transducers. (b) Classification. Class II (performance standards)....

  11. 21 CFR 870.2890 - Vessel occlusion transducer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 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 electrical..., sound, and ultrasonic transducers. (b) Classification. Class II (performance standards)....

  12. 21 CFR 870.2890 - Vessel occlusion transducer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 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 electrical..., sound, and ultrasonic transducers. (b) Classification. Class II (performance standards)....

  13. 21 CFR 870.2890 - Vessel occlusion transducer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Vessel occlusion transducer. 870.2890 Section 870... transducer. (a) Identification. A vessel occlusion transducer is a device used to provide an electrical..., sound, and ultrasonic transducers. (b) Classification. Class II (performance standards)....

  14. 21 CFR 870.2890 - Vessel occlusion transducer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Vessel occlusion transducer. 870.2890 Section 870... transducer. (a) Identification. A vessel occlusion transducer is a device used to provide an electrical..., sound, and ultrasonic transducers. (b) Classification. Class II (performance standards)....

  15. 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.

  16. Relationship between retinal vascular occlusions and incident cerebrovascular diseases

    PubMed Central

    Zhou, Yue; Zhu, Wengen; Wang, Changyun

    2016-01-01

    Abstract Several studies investigating the role of retinal vascular occlusions, on cerebrovascular diseases (CVD) have been reported, but the results are still inconsistent. We therefore sought to evaluate the relationship between retinal vascular occlusions and CVD. We systematically searched the Cochrane Library, PubMed, and ScienceDirect databases through January 31, 2016 for studies evaluating the effect of retinal vascular occlusions on the risk of CVD. Data were abstracted using predefined criteria, and then pooled by RevMan 5.3 software. A total of 9 retrospective studies were included in this meta-analysis. When compared with individuals without retinal vascular occlusions, both individuals with retinal artery occlusion (RAO) (odds ratio [OR] = 2.01, 95% confidence interval [CI]: 1.21–3.34; P = 0.005) and individuals with retinal vein occlusion (RVO) (OR = 1.37, 95% CI: 1.24–1.50; P < 0.00001) had higher risks of developing CVD. Additionally, both individuals with central retinal artery occlusion (CRAO) (OR = 2.00, 95% CI: 1.12–3.56; P = 0.02) and branch retinal artery occlusion (BRAO) (OR = 1.60, 95% CI: 1.03–1.48; P = 0.04) were significantly associated with increased risk of CVD. Published literatures support both RVO and RAO are associated with increased risks of CVD. Further prospective studies are needed to confirm these findings. PMID:27368050

  17. Combined Load Test Fixture

    NASA Technical Reports Server (NTRS)

    Baker, Donald J.

    2010-01-01

    A test fixture has been developed at NASA Langley Research Center that has the capability of applying compression load and shear load simultaneously to a test specimen. The test specimen size is 24-inches by 28-inches. This report describes the test specimen design, test specimen preparation, fixture assembly in the test machine, and a test operation plan.

  18. Monofilament intraluminal middle cerebral artery occlusion in the mouse.

    PubMed

    Clark, W M; Lessov, N S; Dixon, M P; Eckenstein, F

    1997-12-01

    The rat middle cerebral artery (MCA) occlusion model with an intraluminal filament is well characterized with a two hour period of occlusion in widespread use. The recent availability of transgenic animals has led to an interest in adapting the MCA model in the mouse. To date the model has not been well characterized in the mouse. We performed the present study to compare different durations of MCA occlusion and to validate new functional assessments in this model. The MCA occlusion model (5-0 filament) was used. Swiss-Webster mice, 24-44 g, were randomly assigned to four groups: one hour of occlusion; two hours of occlusion; three hours of occlusion; or permanent occlusion. At 48 hours post-ischemia, the animals were rated on three neurologic function scales, and then the brains were removed for lesion size determination. Overall, there was a significant difference in lesion volume (p < 0.001) between the groups. In the permanent group of mice, the average lesion volume was 78.41 +/- 17.47 mm (n = 12); two and three hours of ischemia produced 51.29 +/- 29.82 mm3 (n = 11) and 54.85 mm3 (n = 13), respectively, significantly different than the one hour group 14.84 +/- 31.34 mm3 (n = 11). All three functional scoring systems found significant overall differences between the four groups with our detailed General and Focal scores producing more robust between group treatment differences and showing correlation coefficients of r = 0.766 and r = 0.788, respectively to infarct volume. The MCA filament occlusion model can be successfully adapted in the mouse with either two or three hour occlusions producing reliable infarcts. New functional scoring systems unique to the mouse appear to add additional information. PMID:9427967

  19. 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.

  20. 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. PMID:16388289

  1. Logic-controlled occlusive cuff system

    NASA Technical Reports Server (NTRS)

    Baker, J. T.; Hoffler, G. W. (Inventor); Hursta, W. N.

    1981-01-01

    An occlusive cuff system comprises a pressure cuff and a source of regulated compressed gas feeding the cuff through an electrically operated fill valve. An electrically operated vent valve vents the cuff to the ambient pressure. The fill valve is normally closed and the vent valve is normally open. In response to an external start signal, a logic network opens the fill valve and closes the vent valve, thereby starting the pressurization cycle and a timer. A pressure transducer continuously monitors the pressure in the cuff. When the transducer's output equals a selected reference voltage, a comparator causes the logic network to close the fill valve. The timer, after a selected time delay, opens the vent valve to the ambient pressure, thereby ending the pressurization cycle.

  2. 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.

  3. Acute Aortic Occlusion Presenting as Flaccid Paraplegia

    PubMed Central

    Kilany, Ayman; Al-Hashel, Jasem Y.; Rady, Azza

    2015-01-01

    A 67-year-old male known to be hypertensive and diabetic had a sudden onset of severe low back pain and flaccid paraplegia with no sensory level or bladder affection and the distal pulsations were felt. Acute compressive myelopathy was excluded by MRI of the dorsal and lumbar spines. The nerve conduction study and CSF analysis was suggestive of acute demyelinating polyneuropathy. The patient developed ischemic changes of the lower limb and CT angiography revealed severe stenosis of the abdominal aorta and both common iliac arteries. We emphasize the importance of including acute aortic occlusion in the differential diagnosis of acute flaccid paraplegia especially in the presence of severe back pain even if the distal pulsations were felt. PMID:25866688

  4. Central retinal vein occlusion and pseudoexfoliation syndrome

    PubMed Central

    Karagiannis, Dimitrios; Kontadakis, Georgios A; Klados, Nektarios E; Tsoumpris, Ioannis; Kandarakis, Artemios S; Parikakis, Efstratios A; Georgalas, Ilias; Tsilimbaris, Miltiadis K

    2015-01-01

    Purpose The purpose of this study was to investigate the existence of pseudoexfoliation syndrome (PXF) as a risk factor for the development of central retinal vein occlusion (CRVO). Methods This was a retrospective, comparative study of the prevalence of pseudoexfoliation in three groups of patients: 48 patients with CRVO, 164 patients with branch retinal vein occlusion (BRVO), and 70 control patients (70 eyes). All patients were phakic and had no previous diagnosis of glaucoma. Patients were matched in terms of age and systemic hypertension. All patients had normal intraocular pressure (IOP) at presentation (defined as less than or equal to 21 mmHg). Results In the CRVO group, 14 out of 48 patients were diagnosed as having PXF (29.17%). In the BRVO group, 14 out of 164 patients had PXF (8.5%), and in the control group, six out of 70 patients had PXF (8.6%). Differences of percentage between groups were statistically significant (P<0.001, χ2 test). When comparing patient subgroup with ischemic CRVO with subgroup with non-ischemic CRVO, we found that in the ischemic CRVO group, 13 out of 27 patients were diagnosed as having PXF (48.15%), and in the non-ischemic CRVO group, one out of 21 patients was diagnosed as having PXF (4.7%; P<0.001, χ2 test). The relative odds of having CRVO in patients with PXF versus patients without PXF were 4.406 (confidence interval [CI], 2.03–9.54). Conclusion PXF and CRVO, especially ischemic, are strongly associated in our study. Our results indicate that PXF might be an independent factor for CRVO, as it is related with CRVO independently from glaucoma. PMID:26056437

  5. 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.

  6. Occlusal adjustment using the bite plate-induced occlusal position as a reference position for temporomandibular disorders: a pilot study

    PubMed Central

    2010-01-01

    Background Many researchers have not accepted the use of occlusal treatments for temporomandibular disorders (TMDs). However, a recent report described a discrepancy between the habitual occlusal position (HOP) and the bite plate-induced occlusal position (BPOP) and discussed the relation of this discrepancy to TMD. Therefore, the treatment outcome of evidence-based occlusal adjustments using the bite plate-induced occlusal position (BPOP) as a muscular reference position should be evaluated in patients with TMD. Methods The BPOP was defined as the position at which a patient voluntarily closed his or her mouth while sitting in an upright posture after wearing an anterior flat bite plate for 5 minutes and then removing the plate. Twenty-one patients with TMDs underwent occlusal adjustment using the BPOP. The occlusal adjustments were continued until bilateral occlusal contacts were obtained in the BPOP. The treatment outcomes were evaluated using the subjective dysfunction index (SDI) and the Helkimo Clinical Dysfunction Index (CDI) before and after the occlusal adjustments; the changes in these two indices between the first examination and a one-year follow-up examination were then analyzed. In addition, the difference between the HOP and the BPOP was three-dimensionally measured before and after the treatment. Results The percentage of symptom-free patients after treatment was 86% according to the SDI and 76% according to the CDI. The changes in the two indices after treatment were significant (p < 0.001). The changes in the mean HOP-BPOP differences on the x-axis (mediolateral) and the y-axis (anteroposterior) were significant (p < 0.05), whereas the change on the z-axis (superoinferior) was not significant (p > 0.1). Conclusion Although the results of the present study should be confirmed in other studies, a randomized clinical trial examining occlusal adjustments using the BPOP as a reference position appears to be warranted. PMID:20346167

  7. 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. PMID:26371622

  8. 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. PMID:23412543

  9. Tracheal Occlusion Conditioning in Conscious Rats Modulates Gene Expression Profile of Medial Thalamus

    PubMed Central

    Bernhardt, Vipa; Hotchkiss, Mark T.; Garcia-Reyero, Natàlia; Escalon, B. Lynn; Denslow, Nancy; Davenport, Paul W.

    2011-01-01

    The thalamus may be the critical brain area involved in sensory gating and the relay of respiratory mechanical information to the cerebral cortex for the conscious awareness of breathing. We hypothesized that respiratory mechanical stimuli in the form of tracheal occlusions would modulate the gene expression profile of the thalamus. Specifically, it was reasoned that conditioning to the respiratory loading would induce a state change in the medial thalamus consistent with a change in sensory gating and the activation of molecular pathways associated with learning and memory. In addition, respiratory loading is stressful and thus should elicit changes in gene expressions related to stress, anxiety, and depression. Rats were instrumented with inflatable tracheal cuffs. Following surgical recovery, they underwent 10 days (5 days/week) of transient tracheal occlusion conditioning. On day 10, the animals were sacrificed and the brains removed. The medial thalamus was dissected and microarray analysis of gene expression performed. Tracheal obstruction conditioning modulated a total of 661 genes (p < 0.05, log2 fold change ≥0.58), 250 genes were down-regulated and 411 up-regulated. There was a significant down-regulation of GAD1, GAD2 and HTR1A, HTR2A genes. CCK, PRKCG, mGluR4, and KCJN9 genes were significantly up-regulated. Some of these genes have been associated with anxiety and depression, while others have been shown to play a role in switching between tonic and burst firing modes in the thalamus and thus may be involved in gating of the respiratory stimuli. Furthermore, gene ontology and pathway analysis showed a significant modulation of learning and memory pathways. These results support the hypothesis that the medial thalamus is involved in the respiratory sensory neural pathway due to the state change of its gene expression profile following repeated tracheal occlusions. PMID:21660287

  10. Ocular neovascularization in eyes with a central retinal artery occlusion or a branch retinal artery occlusion

    PubMed Central

    Mason, John O; Patel, Shyam A; Feist, Richard M; Albert, Michael A; Huisingh, Carrie; McGwin, Gerald; Thomley, Martin L

    2015-01-01

    Purpose To investigate the ocular neovascularization (ONV) rate in eyes with a branch retinal artery occlusion (BRAO) or a central retinal artery occlusion (CRAO), and to study factors that may influence the ONV rate secondary to CRAO. Methods This was a retrospective case series of consecutive patients (286 total eyes: 83 CRAOs and 203 BRAOs) who were diagnosed with a retinal artery occlusion from 1998 to 2013 at the Retina Consultants of Alabama and University of Alabama at Birmingham, Birmingham, AL, USA. Generalized estimating equations were used to evaluate the association between hypothesized risk factors and ONV development. Results Twelve (14.5%) of the 83 eyes with a CRAO developed ONV. Eleven of 12 eyes (91.7%) had iris neovascularization, ten of 12 eyes (83.3%) had neovascular glaucoma, and two of 12 eyes (16.7%) had neovascularization of the optic disc. The average time for ONV development secondary to CRAO was 30.7 days, ranging from the date of presentation to 137 days. Only two (<1.0%) of the 203 eyes with a BRAO developed iris neovascularization. Diabetes mellitus type 2 was a risk factor for ONV development following a CRAO with an adjusted odds ratio of 5.2 (95% confidence interval: 1.4–19.8) (P=0.02). Conclusion ONV is an important complication of CRAO and is a less-frequent complication of BRAO. Patients with a CRAO, especially those with diabetes mellitus type 2, should be closely monitored for the first 6 months for ONV. PMID:26089631

  11. Avoiding occlusal derangement in facial fractures: An evidence based approach.

    PubMed

    Mendonca, Derick; Kenkere, Deepika

    2013-05-01

    Facial fractures with occlusal derangement describe any fracture which directly or indirectly affects the occlusal relationship. Such fractures include dento-alveolar fractures in the maxilla and mandible, midface fractures - Le fort I, II, III and mandible fractures of the symphysis, parasymphysis, body, angle, and condyle. In some of these fractures, the fracture line runs through the dento-alveolar component whereas in others the fracture line is remote from the occlusal plane nevertheless altering the occlusion. The complications that could ensue from the management of maxillofacial fractures are predominantly iatrogenic, and therefore can be avoided if adequate care is exercised by the operating surgeon. This paper does not emphasize on complications arising from any particular technique in the management of maxillofacial fractures but rather discusses complications in general, irrespective of the technique used. PMID:24501457

  12. Discordant relationship between Essure microinsert position and tubal occlusion.

    PubMed

    Hou, Melody Y

    2016-01-01

    Hysteroscopic sterilisation with Essure requires confirmation of tubal occlusion by hysterosalpingogram or microinsert position by transvaginal sonography 3 months after placement before women can rely on the method for pregnancy prevention. A 39-year-old woman underwent hysteroscopic sterilisation via Essure, with successful bilateral tubal occlusion documented on hysterosalpingogram. She had a subsequent unintended pregnancy and termination, and presented with persistent pelvic pain and other non-specific symptoms. She underwent a laparoscopic-assisted vaginal hysterectomy with bilateral salpingectomy, with complete resolution of her symptoms. Pathological evaluation demonstrated a perforated Essure microinsert and ipsilateral tubal occlusion, and a correctly placed Essure microinsert with ipsilateral tubal patency. Clinicians should be cautious about the assumption that correctly placed microinserts based on ultrasonography, hysterosalpingogram or laparoscopic evaluation assures occlusion success. PMID:27466315

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

    PubMed

    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

  14. Amplatzer vascular plug for rapid vessel occlusion in interventional neuroradiology.

    PubMed

    Banfield, Jillian C; Shankar, Jai Jai Shiva

    2016-02-01

    The purpose of this paper is to report different uses of endovascular Amplatzer vascular plug (AVP) treatment for rapid vessel occlusion in the field of interventional neuroradiology. We retrospectively reviewed our interventional neuroradiology database from November 2010 to July 2015 and found nine patients who were treated with endovascular AVP. AVP was used for rapid vessel occlusion of common carotid artery (1 patient), internal carotid artery (5 patients), vertebral artery (2 patients), and internal jugular vein (1 patient). A median of three AVPs were used with almost immediate occlusion and no thromboembolic complications. Use of AVP is feasible, safe, rapid, and potentially cost-effective method for rapid occlusion of larger size vessels in the head and neck region for different indications. PMID:26515699

  15. Endobronchial lipoma: a rare cause of bronchial occlusion.

    PubMed

    Triviño, Ana; Mora-Cabezas, Montserrat; Vallejo-Benitez, Ana; García-Escudero, Antonio; González-Cámpora, Ricardo

    2013-11-01

    Endobronchial lipoma is a rare benign neoplasm of the tracheobronchial tree. Despite its benign nature, associated endoluminal polypoid growth can cause bronchial occlusion. In this paper, we present the consequences of a late diagnosis of this condition. PMID:23680317

  16. 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

  17. Cerec: correlation, an accurate and practical method for occlusal reconstruction.

    PubMed

    Prévost, A P; Bouchard, Y

    2001-07-01

    The correlation technique explained here shows one of the possibilities for occlusal reconstruction offered by the Cerec approach. The various stages of this technique are described and illustrated. The most current applications are reviewed. PMID:11862885

  18. Height Gradient Approach for Occlusion Detection in Uav Imagery

    NASA Astrophysics Data System (ADS)

    Oliveira, H. C.; Habib, A. F.; Dal Poz, A. P.; Galo, M.

    2015-08-01

    The use of Unmanned Aerial Vehicle (UAV) significantly increased in the last years. It is used for several different applications, such as mapping, publicity, security, natural disasters assistance, environmental monitoring, 3D building model generation, cadastral survey, etc. The imagery obtained by this kind of system has a great potential. To use these images in true orthophoto generation projects related to urban scenes or areas where buildings are present, it is important to consider the occlusion caused by surface height variation, platform attitude, and perspective projection. Occlusions in UAV imagery are usually larger than in conventional airborne dataset due to the low-altitude and excessive change in orientation due to the low-weight and wind effects during the flight mission. Therefore, this paper presents a method for occlusion detection together with some obtained results for images acquired by a UAV platform. The proposed method shows potential in occlusion detection and true orthophoto generation.

  19. Multiple-Layer Visibility Propagation-Based Synthetic Aperture Imaging through Occlusion

    PubMed Central

    Yang, Tao; Li, Jing; Yu, Jingyi; Zhang, Yanning; Ma, Wenguang; Tong, Xiaomin; Yu, Rui; Ran, Lingyan

    2015-01-01

    Heavy occlusions in cluttered scenes impose significant challenges to many computer vision applications. Recent light field imaging systems provide new see-through capabilities through synthetic aperture imaging (SAI) to overcome the occlusion problem. Existing synthetic aperture imaging methods, however, emulate focusing at a specific depth layer, but are incapable of producing an all-in-focus see-through image. Alternative in-painting algorithms can generate visually-plausible results, but cannot guarantee the correctness of the results. In this paper, we present a novel depth-free all-in-focus SAI technique based on light field visibility analysis. Specifically, we partition the scene into multiple visibility layers to directly deal with layer-wise occlusion and apply an optimization framework to propagate the visibility information between multiple layers. On each layer, visibility and optimal focus depth estimation is formulated as a multiple-label energy minimization problem. The layer-wise energy integrates all of the visibility masks from its previous layers, multi-view intensity consistency and depth smoothness constraint together. We compare our method with state-of-the-art solutions, and extensive experimental results demonstrate the effectiveness and superiority of our approach. PMID:26247949

  20. 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.

  1. Inflammatory reaction as an occlusive mechanism in aortocoronary bypass grafts?

    PubMed

    Svendsen, E; Dalen, H; Moland, J; Engedal, H

    1986-01-01

    Morphological changes in aortocoronary vein grafts are described in two cases; one dying 5 hours post operatively and the other reoperated 8 months after aortocoronary bypass surgery for graft occlusion. Occlusive thrombi and fibrin deposition on the intimal surface and a focal inflammatory process in the wall of the vein grafts were found in the former. Thrombotic encrustation and organization similar to the manifestations of the thrombogenic theory of atherosclerosis were demonstrated in the latter. PMID:3489720

  2. Retino-choroidal ischemia in central retinal vein occlusion

    PubMed Central

    Hussain, Nazimul; Hussain, Anjli

    2014-01-01

    A 41-year-old gentleman with insulin dependent diabetes had decreased vision in the right eye due to non-ischemic central retinal vein occlusion with macular edema. One month following intravitreal ranibizumab, he developed retino-choroidal ischemia with further loss of vision. Authors show the fluorescein angiographic transition from non-ischemic central retinal vein occlusion to retino-choroidal ischemia. PMID:25473353

  3. Can traumatic occlusion cause endodontic problems? A case report.

    PubMed

    Indramohan, Jamuna; Neelakantan, Prasanna; Subba Rao, C V; Vasudevan, C

    2011-01-01

    Radicular cysts are commonly found odontogenic cysts in the jaws. The lesion is diagnosed mainly in young patients during the second decade of life. In the majority of cases, it is asymptomatic. This paper reports a rare case in which traumatic occlusion was identified as the etiology of a radicular cyst. Endodontic treatment was performed and the traumatic occlusion also was corrected. A six-month follow-up appointment found good healing of the periapical region. PMID:21903554

  4. Suspended Load

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The suspended load of rivers and streams consists of the sediments that are kept in the water column by the upward components of the flow velocity. Suspended load may be divided into cohesive and non-cohesive loads which are primarily discriminated by sediment particle size. Non-cohesive sediment ...

  5. Occlusion and periodontal disease--where is the link?

    PubMed

    Fu, Jia Hui; Yap, Adrian U J

    2007-12-01

    The effect of occlusion on the periodontium has been the subject of much debate. Interest on this subject has decreased over the years but has been renewed with the popularity of implant dentistry. This paper reviews the literature and explores the relationship between trauma from occlusion with periodontal disease and peri-implant bone loss. With regards to periodontal disease, there are two schools of thought on the effect that trauma from occlusion has on the periodontium. One believes that trauma from occlusion is a co-destructive factor in the initiation and progression of periodontal disease. The other believes that it is not. Up till now, there are no conclusive explanations on the association between trauma from occlusion and periodontal disease. For dental implants, current literature suggests that there is an association between occlusal overloading and peri-implant bone loss even in the absence of inflammation. However, there is a need for more randomized clinical trials to validate this relationship. PMID:18472527

  6. [Occlusal overload--a risk factor in implant based prostheses].

    PubMed

    Dănilă, V; Augustin, M

    2010-01-01

    The aim of the study was to perform a review of the literature data in regard to the main causes leading to failure of the dental implants and subsequently, of the implant based prostheses. Besides biological risk factors as infection, occlusal overload is considered the main mechanical risk factor being responsible for weakening or fracturing of the fixation screws, fracturing of the prosthesis or even of the implants. Understanding the fundamental differences between the natural dental structures and the implants may lead to a rigorous occlusal control as a key factor to success of implant born prosthesis. Among these, the periodontal ligament is of outmost importance because it allows a physiological-functional adjustment of occlusal stress in the longitudinal axis of the natural teeth and adaptation to the occlusal stress changes. In conclusion, the absence of periodontal ligament may lead to occlusal overload and implant failure due to lack of adjustment of occlusal forces intensity and axial transmission of these forces, as well as the absence of periodontal proprioceptors. PMID:20509305

  7. The influence of stoma occlusion on aspects of tracheoesophageal voice.

    PubMed

    van As, C J; Hilgers, F J; Koopmans-van Beinum, F J; Ackerstaff, A H

    1998-09-01

    In this study, speech of 21 laryngectomized patients is investigated under 2 different stoma occlusion conditions, i.e. direct digital occlusion of the stoma (by thumb or finger), and digital occlusion (by finger) via a special heat and moisture exchanger with speech valve (Provox Stomafilter). For both conditions, acoustical analyses of voice quality (various pitch, amplitude, tremor and harmonicity measures) were performed on a sustained /a/, the mean maximum phonation time was calculated, and a phonetogram was made. Acoustical analysis was possible in 13 of the 21 voices (for the other voices, the pitch was too low or the voice was too aperiodic), but no statistical significant differences were found for any of the acoustical parameters studied. However, the maximum phonation time was significantly longer, and the dynamic range significantly larger, under the Stomafilter occlusion condition. The maximum phonation time showed a relevant improvement in 57% of the patients, while the dynamic range showed a relevant improvement in 35% of the patients. In total, 75% of the patients experience an improvement in one or both of these speech characteristics when using the Stomafilter occlusion. It can be concluded that optimal stoma occlusion by means of a specialized device has a positive influence on two relevant parameters of prosthetic voice production: maximum phonation time and dynamic loudness range. PMID:9840514

  8. Are all mouthguards the same and safe to use? Part 2. The influence of anterior occlusion against a direct impact on maxillary incisors.

    PubMed

    Takeda, Tomotaka; Ishigami, Keiichi; Nakajima, Kazunori; Naitoh, Kaoru; Kurokawa, Katsuhide; Handa, Jun; Shomura, Masahito; Regner, Connell Wayne

    2008-06-01

    The purpose of this study was to clarify the influence anterior occlusion, of mouthguards, has on protecting against a direct collision to the maxillary anterior teeth. In other words, the support mandibular dentition has when wearing a mouthguard. Two types of mouthguards were used for this study, one with an appropriate anterior occlusion or a mouthguard with positive anterior occlusion (MGAO+) and another which was a single-layer mouthguard lacking the same occlusion or a mouthguard with negative anterior occlusion (MGAO-) but with the same thickness on the buccal side. The instruments used for testing were a pendulum-type impact device with two interchangeable impact objects (a steel ball and a baseball), with a plastic jaw model having artificial teeth. Four testing conditions were observed: one with the jaw open without a mouthguard (Open NoMG), the second with the jaw clenching (loaded with 30 kg weight) without a mouthguard (Clench. NoMG), the third with the jaw clenching with MGAO- (Clench. MGAO-) and the last with the jaw clenching with MGAO+ (Clench. MGAO+). The results are as follows: both types of mouthguards showed the effects in reducing the distortion of the teeth. However, the effect was significantly obvious (steel ball = about 57% shock absorption ability, baseball = about 26%) in the mouthguard with anterior occlusion or support by lower dentition through mouthguard (Clench. MGAO+) than Clench. MGAO-. Thus, the influence of anterior occlusion of mouthguards or the support of mandibular dentition through wearing a mouthguard (MGAO+) is indispensable in reducing the impact force and tooth distortion. The results of this research should further contribute to the establishment of guidelines for safer mouthguards. PMID:18489486

  9. 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

  10. 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

  11. Sex Differences During Visual Scanning of Occlusion Events in Infants

    PubMed Central

    Wilcox, Teresa; Alexander, Gerianne M.; Wheeler, Lesley; Norvell, Jennifer M.

    2013-01-01

    A growing number of sex differences in infant behavior have been reported over the last 10 years. One task on which sex differences have been observed reliably is the event-mapping task. In this task, infants view an occlusion event involving 1 or 2 objects, the occluder is removed, and then infants see 1 object sitting on the platform. When the occlusion sequence is complex (i.e., involves paths of motion that change direction when occluded), boys are more likely than girls to detect an inconsistency between a 2-object occlusion event and a 1-object display. The current research used eye-tracking technology to investigate the specific cognitive processes that underlie these sex differences. Three experiments were conducted with 2 age groups of infants with mean ages of 9 months and 4 months. Infants saw a ball–box (2-object) or ball–ball (1-object) occlusion event followed by a 1-ball display; visual scanning of the occlusion event and the 1-ball display was recorded. In the older age group, boys were more likely than girls to visually track the objects through occlusion; they were also more likely to detect an inconsistency between the ball–box event and the 1-ball display (i.e., they visually searched for the missing box). In addition, tracking of the objects through occlusion was related to infants' scanning of the 1-ball display. In the younger age group, both boys and girls failed to track the objects through occlusion and to detect an inconsistency between the ball–box event and the 1–ball display. These results suggest that infants' capacity to track objects through occlusion facilitates extraction of the structure of the initial event (i.e., the number of distinct objects involved), that infants can map onto the final display, and that sex differences in this ability emerge between 4 and 9 months. Possible explanations for how the structure of an occlusion event is extracted and mapped onto a subsequent nonocclusion display are considered. PMID

  12. Prevalent misconceptions about acute retinal vascular occlusive disorders.

    PubMed

    Hayreh, Sohan Singh

    2005-07-01

    Acute retinal vascular occlusive disorders collectively constitute one of the major causes of blindness or seriously impaired vision, and yet there is marked controversy on their pathogeneses, clinical features and particularly their management. This is because the subject is plagued by multiple misconceptions. These include that: (i) various acute retinal vascular occlusions represent a single disease; (ii) estimation of visual acuity alone provides all the information necessary to evaluate visual function; (iii) retinal venous occlusions are a single clinical entity; (iv) retinal vein occlusion is essentially a disease of the elderly and is not seen in the young; (v) central retinal vein occlusion (CRVO) is one disease; (vi) fluorescein fundus angiography is the best test to differentiate ischemic from nonischemic CRVO; (vii) the site of occlusion in CRVO is invariably at the lamina cribrosa; (viii) clinical picture of CRVO is often due to compression or strangulation of the central retinal vein (CRV) in the lamina cribrosa and not its occlusion; (ix) an eye can develop both CRVO and central retinal artery occlusion (CRAO) simultaneously; (x) every eye with CRVO is at risk of developing neovascular glaucoma; (xi) lowering intraocular pressure (IOP) helps to improve retinal circulation in an eye with CRVO; (xii) every patient with retinal vein occlusion should have complete hematologic and coagulation evaluation; (xiii) the natural history of CRVO does not usually involve spontaneous visual improvement; (xiv) management of CRVO is similar to that of venous thrombosis anywhere else in the body, i.e. with aspirin and/or anti-coagulants; (xv) fibrinolytic agents can dissolve an organized thrombus in the CRV; (xvi) it is beneficial to lower blood pressure in patients with CRVO; (xvii) panretinal photocoagulation used in ischemic retinal venous occlusive disorders has no deleterious side-effects; (xviii) glaucoma or ocular hypertension can cause branch retinal vein

  13. Coronary occlusive disease and late graft failure after cardiac transplantation

    PubMed Central

    Mullins, P A; Cary, N R; Sharples, L; Scott, J; Aravot, D; Large, S R; Wallwork, J; Schofield, P M

    1992-01-01

    Objective—Coronary occlusive disease is the main cause of late mortality after cardiac transplantation. It has both similarities and differences compared with conventional atherosclerotic coronary disease. The pathophysiology of late graft failure from coronary occlusive disease is unclear at present. We reviewed the experience of this disorder in our cardiac transplant programme. Design—A retrospective analysis of angiographic and pathological data. Setting—A regional cardiothoracic centre and transplant unit. Patients—Of a population of 383 orthotopic cardiac transplant recipients operated upon between January 1979 and June 1990, 447 coronary angiograms were available for review in 193 patients. Thirteen of a possible 18 results of post mortem examinations from patients dying from coronary occlusive disease were available. Main outcome measure—Coronary occlusive disease was defined as any evidence of disease on coronary angiography. Post mortem examinations were performed with standard techniques. Results The angiographic prevalence of coronary occlusive disease was 3% (1/32 patients) and 40% (19/47 patients) at one and five years respectively. Twenty six grafts failed due to coronary occlusive disease compared with 132 graft failures from all causes during this period. Acute thrombosis was present in a large vessel in seven of 13 fatal cases undergoing necropsy (54%). Noticeable large vessel involvement with disease in smaller distal vessels was present in four patients (31%). The remaining two patients (15%) had small vessel disease alone. Twelve of the 13 patients had significant cardiomegaly (cardiac weight ≥400 g) with a mean weight of 510 (range 370-740) g. Conclusion—Coronary occlusive disease is the main late complication after cardiac transplantation. A combination of coronary thrombosis, ischaemia from stenoses of large and small coronary vessels, and cardiomegaly contribute to the graft failure of these patients. PMID:1389755

  14. Colectomy in patients with previous colectomy or occlusive vascular diseases: Pitfalls and precautions.

    PubMed

    Prevot, F; Sabbagh, C; Mauvais, F; Regimbeau, J-M

    2016-04-01

    Two principal branches from the aorta provide the colonic blood supply: the superior and inferior mesenteric arteries. There are numerous anatomical variations, which the surgeon must fully understand before embarking on any colonic surgery. A good knowledge of these variations is particularly important when the patient has already undergone colectomy or presents with occlusive vascular disease. The aim of this review is to summarize the standard anatomy and the main variations of the colonic blood supply as they apply to colorectal surgery in this setting. PMID:27009920

  15. 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

  16. Imaging natural occlusal caries lesions with optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Douglas, Shane M.; Fried, Daniel; Darling, Cynthia L.

    2010-02-01

    Several studies have demonstrated that polarization-sensitive optical coherence tomography (PS-OCT) can be used to nondestructively measure the severity of demineralization in the important occlusal surfaces. The purpose of this study was to assess the potential of PS-OCT and OCT methods for the measurement of the depth of natural occlusal carious lesions. Teeth were screened for potential occlusal lesions using near infrared imaging (NIR). A PS-OCT system operating at 1310-nm was used to acquire polarization resolved images of the area of interest on the occlusal surface. The teeth were serial sectioned to 200 μm thickness and examined with polarized light microscopy (PLM) and Transverse Microradiography (TMR) for comparison. The lesion depth measured nondestructively with PS-OCT was compared to the lesion depth measured with PLM and TMR to assess the performance of these methods and determine if polarization sensitivity is required. The lesion depth measured using OCT correlated well with the lesion depths measured with TMR and PLM. Although polarization sensitivity provided better contrast it was not necessary to have polarization sensitivity to identify deep occlusal lesions.

  17. Occlusive versus nonocclusive calcipotriol ointment treatment for palmoplantar psoriasis.

    PubMed

    Duweb, G A; Abuzariba, O; Rahim, M; al-Taweel, M; al-Alem, S; Abdulla, S A

    2001-01-01

    Thirty-nine patients with a clinical diagnosis of palmoplantar psoriasis [23 (58%) males and 16 (42%) females] were included in this study with the aim of evaluating the efficacy of occlusive calcipotriol 50 micrograms/mg ointment vs. nonocclusive therapy. Patients were randomized to either twice-weekly overnight calcipotriol ointment under occlusion or twice-daily topical nonocclusive application of the same ointment for 6 weeks. The effect of treatment was assessed on the basis of a psoriasis signs score for erythema, thickness and scaliness, which was graded from 0 (absent) to 4 (most severe) at the first visit, after 2 weeks and at the end of treatment. Analysis of our results showed that twice-weekly occlusive calcipotriol ointment was as effective as the twice-daily application. The mean total score at baseline was 6 for the occlusive group and 6.1 for the nonocclusive group. The score decreased to 1.5 in both groups at the end of treatment. No significant adverse effects were reported by patients or investigators. We conclude that occlusive calcipotriol ointment is effective in the treatment of palmoplantar psoriasis and may produce even better results with more frequent use, such as application on alternate days. PMID:11447774

  18. 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.

  19. The muscle engram: the reflex that limits conventional occlusal treatment.

    PubMed

    Lerman, Martin D

    2011-10-01

    The engram (the masticatory "muscle memory") is shown to be a conditionable reflex whose muscle conditioning lasts less than two minutes, far shorter than previously thought. This reflex, reinforced and stored in the masticatory muscles at every swallow, adjusts masticatory muscle activity to guide the lower arch unerringly into its ICP. These muscle adjustments compensate for the continually changing intemal and external factors that affect the mandible's entry into the ICP. A simple quick experiment described in this article isolates the engram, enabling the reader to see its action clearly for the first time. It is urged that every reader perform this experiment. This experiment shows how the engram, by hiding the masticatory muscles' reaction (the hit-and-slide), limits the success of the therapist in achieving occlusion-muscle compatibility. This finding has major clinical implications. It means that, as regards the muscle aspect of treating occlusion, the dentist treating occlusion conventionally is working blind, a situation the neuromuscular school of occlusal thought seeks to correct. The controversy over occlusion continues. PMID:22128670

  20. Respiratory flow-resistive load compensation during sleep.

    PubMed

    Santiago, T V; Sinha, A K; Edelman, N H

    1981-04-01

    We studied ventilation, arterial blood gas tensions, and the ventilatory and airway occlusion pressure responses to hypercapnia of eight cats during wakefulness, quiet (slow-wave) sleep, and active (rapid-eye-movement) sleep. Responses to hypercapnia were measured before and during added airway resistance. Ventilation decreased, and arterial PCO2 increased during both slow-wave and rapid-eye-movement sleep. Unloaded ventilatory and airway occlusion pressure responses to hypercapnia decreased during slow-wave and rapid-eye-movement sleep as well. Flow-resistive loading caused awake cats to increase their occlusion pressure response to hypercapnia, thereby preserving their ventilatory responses. In contrast, during both slow-wave and rapid-eye-movement sleep, cats showed no augmentation of the occlusion pressure response and concomitant decrease of the ventilatory response to hypercapnia with the load. Thus, sleep was associated with loss of flow-resistive load compensation. It is postulated that, in an appropriate setting, this phenomenon could serve a protective function by decreasing the chances for progression from partial to complete upper airway obstruction during sleep. PMID:6784623

  1. 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.

  2. Orthodontic goniometry: a control technique after P. Planas transversal expansion method: neuro-occlusal rehabilitation: Part 3.

    PubMed

    Chateau, M; Planas, C S

    1995-01-01

    Orthodontic goniometry applied to expansion cases treated by P. Planas method (neuro-occlusal rehabilitation) demonstrates considerable bimaxillary transverse expansion (crown and apices). Maximal expansion of 10 mm was noted for mandibular apices with a mean of 5.8 mm. Maximal expansion of 11.5 mm was noted for maxillary apices with a mean of 8.11 mm. Results were stable, some being controlled more than eight years out of retention. PMID:8611485

  3. 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

  4. Transcatheter patch occlusion of experimental atrial septal defects.

    PubMed

    Sideris, Eleftherios B; Sideris, Chrysoula E; Stamatelopoulos, Stamatis F; Moulopoulos, Spyridon D

    2002-11-01

    The effectiveness and safety of transcatheter patch atrial septal defect (ASD) occlusion were studied in 20 piglets. Experimental atrial septal defects were created by foramen ovale dilation. ASDs were corrected by polyurethane patches of two types (flat and sleeve). Specially made balloon catheters supported the patches for periods varying from 1 to 6 days; after this period, the supporting catheters were withdrawn and the patches were released. All transcatheter patches were safely embedded in the atrial septum 48 hr or more after implantation. All defects were fully occluded. One patch became infected. The transcatheter patch experimental ASD occlusion method was found effective and safe, potentially applicable in the occlusion of human ASDs. PMID:12410521

  5. Imaging of occlusive thrombi in acute ischemic stroke

    PubMed Central

    Gasparian, GG; Sanossian, N; Shiroishi, MS; Liebeskind, DS

    2015-01-01

    Thrombi, or clots, often occlude proximal segments of the cerebral arterial circulation in acute ischemic stroke. Thromboembolic occlusion or thrombi superimposed on atherosclerotic plaque are the principal focus of acute stroke therapies such as thrombolysis or thrombectomy. We review the imaging characteristics of thrombi on multimodal CT and MRI, angiography and ultrasonography, summarizing recent studies that facilitate therapeutic decision-making from these noninvasive studies. Information about the location, size and imaging characteristics can be ascertained using these techniques. Imaging findings in relation to occlusive thrombus have been correlated with clot pathology, response to therapeutic interventions, and clinical outcome. Diagnostic evaluation of occlusive thrombi on noninvasive studies now constitutes an integral component of acute stroke management. PMID:25545291

  6. Endovascular Treatment of Veno-Occlusive Behcet's Disease

    SciTech Connect

    Tekbas, Guven; Oguzkurt, Levent Gur, Serkan; Onder, Hakan; Andic, Cagatay

    2012-08-15

    Purpose: To retrospectively evaluate the outcome of endovascular treatments for patients with chronic veno-occlusive disease in different vascular beds secondary to Behcet's disease (BD). There are few case reports on the subject, and this is the largest study to date. Materials and Methods: From January 2001 through October 2009, chronic venous occlusions were treated in 10 patients (all male [age range 18-76 years]) with BD using percutaneous transluminal angioplasty and/or stent placement. All patients were symptomatic and had chronic iliofemoral deep venous thrombosis (DVT; n = 5), central venous occlusion (n = 3), or Budd-Chiari syndrome (BCS; n = 2). All patients met criteria of the International Study Group on Behcet's Disease. Results: Two of five patients with DVT had unsuccessful recanalization attempts. Three patients had successful recanalization with stent placement. All three veins were occluded within 1 month with unsuccessful reinterventions. Three patients with chronic central venous occlusion had successful recanalization with percutaneous transluminal angioplasty (n = 1) and stent placement (n = 2). Two patients had reocclusion with successful reintervention. Two BCS patients had successful treatment with stent placements. Overall technical success was 69%, and no procedural complications were encountered. None of the patients with chronic DVT had patent veins; however, all patients with central venous occlusion or BCS had patent veins on color Doppler ultrasonography at follow-up ranging from 3 to 48 months after intervention. Conclusion: Endovenous treatment for chronic iliofemoral DVT due to BD had a poor outcome. However, long-term outcome after endovenous treatment for upper-extremity central venous occlusion and BCS syndrome was good.

  7. Mechanisms of Biliary Plastic Stent Occlusion and Efforts at Prevention

    PubMed Central

    Kwon, Chang-Il; Lehman, Glen A.

    2016-01-01

    Biliary stenting via endoscopic retrograde cholangiopancreatography has greatly improved the quality of patient care over the last 30 years. Plastic stent occlusion limits the life span of such stents. Attempts to improve plastic stent patency duration have mostly failed. Metal stents (self-expandable metal stents [SEMSs]) have therefore replaced plastic stents, especially for malignant biliary strictures. SEMS are at least 10 times more expensive than plastic stents. In this focused review, we will discuss basic mechanisms of plastic stent occlusion, along with a systematic summary of previous efforts and related studies to improve stent patency and potential new techniques to overcome existing limitations. PMID:27000422

  8. From function to esthetics: anterior or occlusal compromises to esthetics.

    PubMed

    Guichet, D L; Guichet, N F

    1993-01-01

    Increased patient expectations together with improved diagnostic, material, and surgical advances have expanded the boundaries of esthetic dentistry. To optimize functional and esthetic success, existing techniques are being enhanced through careful patient selection and management of the occlusion. During the period from 1991 to 1992, several areas relating anterior or occlusal compromises to esthetics have been identified. These include: dental and skeletal malocclusion, periodontal esthetic defects, restorative materials and laboratory techniques, tooth arrangement and maxillomandibular relations, and implant dentistry. This paper reviews some of the literature on these areas during this period. PMID:8401825

  9. Central retinal vein occlusion in a migraine patient.

    PubMed

    Benninger, Felix; Saban, Tal; Steiner, Israel

    2015-11-01

    We describe a 31-year-old woman with a history of migraines without aura, who presented to our emergency department due to a monocular visual disturbance. This was misdiagnosed as being related to her migraine, however, it was subsequently found to be caused by a central retinal vein occlusion. Patients suffering from migraine can experience visual disturbances in the form of auras. The neuropathological basis for this phenomenon is thought to be a spreading depression in the visual cortex, causing a hemifield active visual phenomenon. Missing the diagnosis of central retinal vein occlusion is common, especially in the setting of an initially normal fundoscopy examination. PMID:26115899

  10. Scintigraphic patterns of veno-occlusive disease in liver transplantation.

    PubMed

    Bernstine, Hanna; Mor, Eytan; Ben Ari, Ziv; Belinki, Alexander; Hardoff, Ruth

    2004-05-01

    Venous vascular complications in liver transplant recipients are rare. Diagnosis is usually based on clinical criteria and typical findings on liver biopsy. The scintigraphic patterns of posttransplant liver veno-occlusive disease are described, and the value of follow-up studies is suggested. The authors present 2 patients who developed posttransplantation hepatic veno-occlusive disease. The first patient had a severe form of the disease and a fatal outcome. The second patient had a mild to moderate form of this disorder with complete resolution following treatment. PMID:15069326

  11. Double steal phenomenon secondary to innominate artery occlusion.

    PubMed

    Esen, Kaan; Yilmaz, Cengiz; Kaya, Omer; Soker, Gokhan; Gulek, Bozkurt; Sahin, Durmus Yildiray

    2016-07-01

    Innominate artery steno-occlusive disease is a relatively rare clinical entity and may cause cerebrovascular symptoms. Herein, we report a 50-year-old male patient who presented with recurrent syncopal episodes and cerebrovascular ischemia. Color Doppler sonography revealed a distinctive flow pattern with partial and total flow reversal in the right internal carotid artery and vertebral artery, respectively. Further angiographic evaluation revealed complete occlusion of the innominate artery. Endovascular stenting was successful and enabled normal antegrade flow in the right common carotid and vertebral artery. PMID:27107766

  12. Transcatheter patch occlusion of perimembranous ventricular septal defects.

    PubMed

    Sideris, Eleftherios B; Macuil, Benjamin; Varvarenko, Victor; Toumanides, Savvas

    2005-06-15

    Sixteen surgical candidates for ventricular septal defect correction were brought to the catheterization laboratory for transcatheter patch occlusion. There were 3 cases of nonrestrictive ventricular septal defects, including 2 with malalignment (tetralogy of Fallot). All patients, except those with tetralogy of Fallot who were cyanotic, had large left-right shunts. They were all corrected through the femoral vein. All defects with the exception of 2 were successfully occluded (12 full occlusions, 2 residual shunts). On follow-up, there were no embolizations, aortic insufficiency, or other complications. The method appears effective and relatively safe, and could challenge the current surgical standard of treatment. PMID:15950588

  13. 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. PMID:26835946

  14. Mechanisms of Biliary Plastic Stent Occlusion and Efforts at Prevention.

    PubMed

    Kwon, Chang-Il; Lehman, Glen A

    2016-03-01

    Biliary stenting via endoscopic retrograde cholangiopancreatography has greatly improved the quality of patient care over the last 30 years. Plastic stent occlusion limits the life span of such stents. Attempts to improve plastic stent patency duration have mostly failed. Metal stents (self-expandable metal stents [SEMSs]) have therefore replaced plastic stents, especially for malignant biliary strictures. SEMS are at least 10 times more expensive than plastic stents. In this focused review, we will discuss basic mechanisms of plastic stent occlusion, along with a systematic summary of previous efforts and related studies to improve stent patency and potential new techniques to overcome existing limitations. PMID:27000422

  15. 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.

  16. Retinal arterial occlusive disease in systemic lupus erythematosus.

    PubMed

    Gold, D; Feiner, L; Henkind, P

    1977-09-01

    Four patients with systemic lupus erythematosus (SLE) developed an unusual form of occlusive retinal arterial disease. The most prominent clinical features of this disorder were deposition of yellow-white material in retinal arterial walls and evidence of multifocal retinal arterial occlusion. Fluorescein angiographic findings included nonperfusion of the obstructed arteries and the retinal capillary beds fed by them, and fluorescein leakage at the sites of involvement of the retinal arteries. This ocular complication of SLE is presumably a manifestation of the widespread systemic vascular problems seen in this disorder. It may be more common in patients with lupus involving the CNS. PMID:901267

  17. Sinus bradycardia as a predictor of right coronary artery occlusion in patients with inferior myocardial infarction.

    PubMed

    Serrano, C V; Bortolotto, L A; César, L A; Solimene, M C; Mansur, A P; Nicolau, J C; Ramires, J A

    1999-01-01

    Differentiation of right coronary artery (RCA) from left circumflex artery (LCxA) occlusion may be difficult since both can present an electrocardiographic pattern of inferior myocardial infarction (IMI). We studied 133 patients with IMI, 92 patients with RCA occlusion and 41 patients with LCxA occlusion. Risk factors such as previous MI, arterial hypertension, diabetes, smoking, and dislipemia, were similar for RCA and LCxA occlusions. Patients with RCA occlusion had a higher incidence of isolated IMI than patients with LCxA occlusion, 50% vs. 17%, respectively (P<0.001). Arterial hypotension was more prevalent (P<0.05) among patients with RCA (18%) rather than those with LCxA occlusion (2%). RCA occlusion presented an association with sinus bradycardia, an association not observed with LCxA occlusion (15% vs. 0%, respectively; P<0.01). Total atrioventricular block was only present among patients with RCA (18%). Proximal occlusions of the RCA presented lower heart rates (sinus bradycardia) than medial and distal occlusions (13% vs. 1% and 1%, respectively; P<0.0001 and P<0.001). Therefore, regarding patients with IMI: (1) sinus bradycardia is more frequent when the infarct-related artery is the RCA; (2) proximal occlusions of the right coronary predispose low heart rates; and (3) occlusion of the LCxA rarely induces sinus bradycardia. PMID:10077404

  18. Load proportional safety brake

    NASA Technical Reports Server (NTRS)

    Cacciola, M. J.

    1979-01-01

    This brake is a self-energizing mechanical friction brake and is intended for use in a rotary drive system. It incorporates a torque sensor which cuts power to the power unit on any overload condition. The brake is capable of driving against an opposing load or driving, paying-out, an aiding load in either direction of rotation. The brake also acts as a no-back device when torque is applied to the output shaft. The advantages of using this type of device are: (1) low frictional drag when driving; (2) smooth paying-out of an aiding load with no runaway danger; (3) energy absorption proportional to load; (4) no-back activates within a few degrees of output shaft rotation and resets automatically; and (5) built-in overload protection.

  19. Transient Aortic Occlusion Augments Collateral Blood Flow and Reduces Mortality During Severe Ischemia due to Proximal Middle Cerebral Artery Occlusion.

    PubMed

    Ramakrishnan, Gomathi; Dong, Bin; Todd, Kathryn G; Shuaib, Ashfaq; Winship, Ian R

    2016-04-01

    Cerebral collateral circulation provides alternative vascular routes for blood to reach ischemic tissues during stroke. Collateral therapeutics attempt to augment flow through these collateral channels to reduce ischemia and brain damage during acute ischemic stroke. Transient aortic occlusion (TAO) has pre-clinical data suggesting that it can augment collateral blood flow and clinical data suggesting a benefit for patients with moderate cortical strokes. By diverting blood from the periphery towards the cerebral circulation, TAO has the potential to augment primary collateral flow at the circle of Willis and thereby improve outcome even during large, hemispheric strokes. Using proximal middle and anterior cerebral artery occlusion in rats, we demonstrate that TAO reduces mortality and improves collateral blood flow in severely ischemic animals. As such, TAO may be an effective therapy to reduce early mortality during severe ischemia associated with proximal occlusions. PMID:26706246

  20. Effect of brovincamine on cerebral circulation and metabolism in internal carotid artery occlusion examined by positron emission tomography.

    PubMed

    Yamaguchi, S; Fukuyama, H; Yonekura, Y; Konishi, J

    1992-01-01

    We evaluated the effect of brovincamine on the circulatory and metabolic state in the brain ischemia with internal carotid artery occlusion accompanying the 'misery perfusion syndrome'. Cerebral blood flow (CBF), cerebral metabolic rate of oxygen (CMRO2) and oxygen extraction fraction (OEF) were measured by PET before and after intravenous loading of brovincamine. Brovincamine increased CBF and decreased OEF significantly on the occluded side of the hemisphere. CMRO2 did not show any remarkable changes upon brovincamine administration. It was concluded that brovincamine might be useful for increasing the hemodynamic reserve, but did not affect the metabolic state immediately after its administration. PMID:1490496

  1. Cortical Processing of Respiratory Occlusion Stimuli in Children with Central Hypoventilation Syndrome

    PubMed Central

    Huang, Jingtao; Marcus, Carole L.; Bandla, Preetam; Schwartz, Michael S.; Pepe, Michelle E.; Samuel, John M.; Panitch, Howard B.; Bradford, Ruth M.; Mosse, Yael P.; Maris, John M.; Colrain, Ian M.

    2008-01-01

    Rationale: The ability of patients with central hypoventilation syndrome (CHS) to produce and process mechanoreceptor signals is unknown. Objectives: Children with CHS hypoventilate during sleep, although they generally breathe adequately during wakefulness. Previous studies suggest that they have compromised central integration of afferent stimuli, rather than abnormal sensors or receptors. Cortical integration of afferent mechanical stimuli caused by respiratory loading or upper airway occlusion can be tested by measuring respiratory-related evoked potentials (RREPs). We hypothesized that patients with CHS would have blunted RREP during both wakefulness and sleep. Methods: RREPs were produced with multiple upper airway occlusions and were obtained during wakefulness, stage 2, slow-wave, and REM sleep. Ten patients with CHS and 20 control subjects participated in the study, which took place at the Children's Hospital of Philadelphia. Each patient was age- and sex-matched to two control subjects. Wakefulness data were collected from 9 patients and 18 control subjects. Measurements and Main Results: During wakefulness, patients demonstrated reduced Nf and P300 responses compared with control subjects. During non-REM sleep, patients demonstrated a reduced N350 response. In REM sleep, patients had a later P2 response. Conclusions: CHS patients are able to produce cortical responses to mechanical load stimulation during both wakefulness and sleep; however, central integration of the afferent signal is disrupted during wakefulness, and responses during non-REM are damped relative to control subjects. The finding of differences between patients and control subjects during REM may be due to increased intrinsic excitatory inputs to the respiratory system in this state. PMID:18658113

  2. Excess Salt Increases Infarct Size Produced by Photothrombotic Distal Middle Cerebral Artery Occlusion in Spontaneously Hypertensive Rats

    PubMed Central

    Yao, Hiroshi; Nabika, Toru

    2014-01-01

    Cerebral circulation is known to be vulnerable to high salt loading. However, no study has investigated the effects of excess salt on focal ischemic brain injury. After 14 days of salt loading (0.9% saline) or water, spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY) were subjected to photothrombotic middle cerebral artery occlusion (MCAO), and infarct volume was determined at 48 h after MCAO: albumin and hemoglobin contents in discrete brain regions were also determined in SHR. Salt loading did not affect blood pressure levels in SHR and WKY. After MCAO, regional cerebral blood flow (CBF), determined with two ways of laser-Doppler flowmetry (one-point measurement or manual scanning), was more steeply decreased in the salt-loaded group than in the control group. In SHR/Izm, infarct volume in the salt-loaded group was 112±27 mm3, which was significantly larger than 77±12 mm3 in the control group (p = 0.002), while the extents of blood-brain barrier disruption (brain albumin and hemoglobin levels) were not affected by excess salt. In WKY, salt loading did not significantly increase infarct size. These results show the detrimental effects of salt loading on intra-ischemic CBF and subsequent brain infarction produced by phototrhombotic MCAO in hypertensive rats. PMID:24816928

  3. [Backshifting of lower canines in occlusion regulation].

    PubMed

    Michałowska-Sarosiek, A; Wedrychowska-Szulc, B; Doniec-Zawidzka, I

    1990-08-01

    In 17 patients the lower canines were shifted back during treatment of prognathic malocclusion and cross-bites. Stable devices with retraction loops, rubber or spring traction were used. The duration of active treatment was about 3 months, on average. During the treatment gaps after the removed premolars were closed completely, although this is nearly impossible when removable devices are applied. PMID:2104380

  4. Occlusal Caries Management: Preferences among Dentists in Norway.

    PubMed

    Kopperud, Simen E; Tveit, Anne B; Opdam, Niek J M; Espelid, Ivar

    2016-01-01

    The aim was to measure variations in the threshold for operative treatment of occlusal caries in permanent teeth and the use of dental materials, compared with results from a similar study conducted in Norway in 1995. In 2009, a precoded questionnaire was sent electronically to 3,654 dentists with E-mail addresses in the member register of the Norwegian Dental Association. The questions were related to caries, treatment strategies and choice of dental materials. Replies were obtained from 61.3% respondents after two reminders. Restorative treatment of occlusal lesions confined to enamel was proposed by 12% of the dentists, compared with 18% in 1995 (p < 0.01). Older dentists more often than younger dentists would operatively treat enamel lesions (p < 0.01). Most dentists preferred to drill only the carious part of the fissure rather than the whole fissure both in 2009 (78.8%) and 1995 (68.3%; p < 0.01). In 2009, 91.9% preferred composite as the restorative material of choice, compared to only 39.1% in 1995. Logistic regression analyses identified higher age of the dentist as the only variable significantly associated with higher risk of restoring occlusal enamel lesions operatively. The authors conclude that especially young dentists appear to be more reluctant to remove tooth substance in 2009 compared with 1995. Composite is the dominating material of choice in 2009 and seems to have substituted the use of most other filling materials in occlusal restorations in permanent teeth. PMID:26839953

  5. 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,…

  6. Centric slide in different Angle's classes of occlusion.

    PubMed

    Čimić, Samir; Badel, Tomislav; Šimunković, Sonja Kraljević; Pavičin, Ivana Savić; Ćatić, Amir

    2016-01-01

    The purpose of this study was to test the possible differences in centric slide values between different Angle's classes of occlusion. The study included 98 participants divided into four groups: Angle's class I, Angle's class II, subdivision 1, Angle's class II, subdivision 2 and Angle's class III. All recordings were obtained using an ultrasound jaw tracking device with six degrees of freedom. The distance between the maximum intercuspation (reference position) and the centric occlusion was recorded at the condylar level. Anteroposterior, superoinferior and transversal distance of the centric slide were calculated for each participant, and the data were statistically analyzed (analysis of variance and Newman-Keuls post hoc test). No statistically significant difference was found in the anteroposterior and transversal distance of the centric slide between tested groups, while Angle's class II, subdivision 2 showed smaller vertical amount of the centric slide compared to Angle's class I and class II, subdivision 1. None of the 98 participants showed coincidence of centric occlusion and maximum intercuspation. Our results suggest that coincidence of the maximum intercuspation with the centric occlusion should not be expected. Smaller extent of the vertical distance of the centric slide could be morphological and a functional expression characteristic of the Angle's class II, subdivision 2. PMID:26434757

  7. 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.

  8. Learning about Occlusion: Initial Assumptions and Rapid Adjustments

    ERIC Educational Resources Information Center

    Kochukhova, Olga; Gredeback, Gustaf

    2007-01-01

    We examined 6-month-olds' abilities to represent occluded objects, using a corneal-reflection eye-tracking technique. Experiment 1 compared infants' ability to extrapolate the current pre-occlusion trajectory with their ability to base predictions on recent experiences of novel object motions. In the first condition infants performed at asymptote…

  9. Young Infants' Perception of Unity and Form in Occlusion Displays.

    ERIC Educational Resources Information Center

    Johnson, Scott P.; Bremner, J. Gavin; Slater, Alan M.; Mason, Uschi C.; Foster, Kirsty

    2002-01-01

    A recognition-based paradigm was used to investigate possibility that past research failed to sensitively assess infants' perception of the unity of misaligned edges in partial occlusion displays. Results suggested that habituation designs tapping recognition processes may be particularly efficacious in revealing infants' perceptual organization.…

  10. 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

  11. Three hypothesis algorithm with occlusion reasoning for multiple people tracking

    NASA Astrophysics Data System (ADS)

    Reta, Carolina; Altamirano, Leopoldo; Gonzalez, Jesus A.; Medina-Carnicer, Rafael

    2015-01-01

    This work proposes a detection-based tracking algorithm able to locate and keep the identity of multiple people, who may be occluded, in uncontrolled stationary environments. Our algorithm builds a tracking graph that models spatio-temporal relationships among attributes of interacting people to predict and resolve partial and total occlusions. When a total occlusion occurs, the algorithm generates various hypotheses about the location of the occluded person considering three cases: (a) the person keeps the same direction and speed, (b) the person follows the direction and speed of the occluder, and (c) the person remains motionless during occlusion. By analyzing the graph, our algorithm can detect trajectories produced by false alarms and estimate the location of missing or occluded people. Our algorithm performs acceptably under complex conditions, such as partial visibility of individuals getting inside or outside the scene, continuous interactions and occlusions among people, wrong or missing information on the detection of persons, as well as variation of the person's appearance due to illumination changes and background-clutter distracters. Our algorithm was evaluated on test sequences in the field of intelligent surveillance achieving an overall precision of 93%. Results show that our tracking algorithm outperforms even trajectory-based state-of-the-art algorithms.

  12. Delayed Axillary Artery Occlusion after Reverse Total Shoulder Arthroplasty

    PubMed Central

    Heitmiller, Richard F.

    2016-01-01

    Axillary artery injury has been associated with shoulder dislocation and surgery. We describe a case of delayed axillary artery occlusion after reverse total shoulder arthroplasty. The injury was confirmed by Doppler and angiography and was treated with angioplasty and stenting. Early recognition and treatment of this injury are mandatory for patients' recovery. PMID:27555975

  13. 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…

  14. Overcoming the challenge of venous occlusion for lead implantation

    PubMed Central

    Burri, Haran

    2015-01-01

    Vein stenosis or occlusion is a frequent finding in patients with previously-implanted transvenous leads. This editorial describes the different techniques that may be used to overcome this hurdle in case a new lead needs to be implanted, and discusses two case reports in this issue of the journal. PMID:26937095

  15. In Vivo Imaging of Stepwise Vessel Occlusion in Cerebral Photothrombosis of Mice by 19F MRI

    PubMed Central

    Kleinschnitz, Christoph; Kampf, Thomas; Jakob, Peter M.; Stoll, Guido

    2011-01-01

    Background 19F magnetic resonance imaging (MRI) was recently introduced as a promising technique for in vivo cell tracking. In the present study we compared 19F MRI with iron-enhanced MRI in mice with photothrombosis (PT) at 7 Tesla. PT represents a model of focal cerebral ischemia exhibiting acute vessel occlusion and delayed neuroinflammation. Methods/Principal Findings Perfluorocarbons (PFC) or superparamagnetic iron oxide particles (SPIO) were injected intravenously at different time points after photothrombotic infarction. While administration of PFC directly after PT induction led to a strong 19F signal throughout the entire lesion, two hours delayed application resulted in a rim-like 19F signal at the outer edge of the lesion. These findings closely resembled the distribution of signal loss on T2-weighted MRI seen after SPIO injection reflecting intravascular accumulation of iron particles trapped in vessel thrombi as confirmed histologically. By sequential administration of two chemically shifted PFC compounds 0 and 2 hours after illumination the different spatial distribution of the 19F markers (infarct core/rim) could be visualized in the same animal. When PFC were applied at day 6 the fluorine marker was only detected after long acquisition times ex vivo. SPIO-enhanced MRI showed slight signal loss in vivo which was much more prominent ex vivo indicative for neuroinflammation at this late lesion stage. Conclusion Our study shows that vessel occlusion can be followed in vivo by 19F and SPIO-enhanced high-field MRI while in vivo imaging of neuroinflammation remains challenging. The timing of contrast agent application was the major determinant of the underlying processes depicted by both imaging techniques. Importantly, sequential application of different PFC compounds allowed depiction of ongoing vessel occlusion from the core to the margin of the ischemic lesions in a single MRI measurement. PMID:22194810

  16. Dentin caries activity in early occlusal lesions selected to receive operative treatment

    PubMed Central

    Lehmann, Maryann; Veitz-Keenan, Analia; Matthews, Abigail G.; Vena, Donald; Grill, Ashley; Craig, Ronald G.; Curro, Frederick A.; Thompson, Van P.

    2014-01-01

    Background Members of the practice-based research network Practitioners Engaged in Applied Research and Learning (PEARL) Network investigated the dentin caries activity in early occlusal lesions and its relationship to patient age, preoperative tooth sensitivity and radio-graphic appearance, as well as its influence on preparation depth and volume. Methods PEARL Network practitioner-investigators (P-Is) (n = 45), general dentists who were trained but whose methods were not calibrated, conducted a study regarding postoperative hypersensitivity in resin-based composite restorations. The P-Is enrolled as study participants 613 patients with occlusal carious lesions that, in the P-Is’ clinical judgment, required restoration. The P-Is used baseline radiographs to assess the depth and extent of the lesions. Data for 671 restorations included baseline sensitivity; ranking of dentin caries activity on the opening of the enamel; radiographic visibility (n = 652); and measurements of preparation depth, width and length. Results P-Is found rapidly progressing dentin caries in 38.5 percent (258 of 671) of lesions and slowly progressing (and potentially inactive dentin) caries in the remainder of the lesions. Rapidly progressing caries was not related to the participant’s age or participant-reported preoperative hypersensitivity but was related to the lesion depth as seen radiographically (P < .001) and depth (P < .001) and volume (P < .001) of the preparation. Molars had slightly higher but not statistically significant levels of caries activity. Conclusion Rapidly progressing dentin caries, while present in only 38.5 percent of lesions, was related to the lesion’s radiographic appearance but not to the participant’s age or the study tooth’s pre-operative sensitivity. Clinical Implications On the basis of the low level of rapidly progressing dentin caries in this study population and the fact that slowly progressing caries can be inactive or remineralizing, the

  17. Effect of compositions in nanostructured lipid carriers (NLC) on skin hydration and occlusion

    PubMed Central

    Loo, CH; Basri, M; Ismail, R; Lau, HLN; Tejo, BA; Kanthimathi, MS; Hassan, HA; Choo, YM

    2013-01-01

    Purpose To study the effects of varying lipid concentrations, lipid and oil ratio, and the addition of propylene glycol and lecithin on the long-term physical stability of nanostructured lipid nanocarriers (NLC), skin hydration, and transepidermal water loss. Methods The various NLC formulations (A1–A5) were prepared and their particle size, zeta potential, viscosity, and stability were analyzed. The formulations were applied on the forearms of the 20 female volunteers (one forearm of each volunteer was left untreated as a control). The subjects stayed for 30 minutes in a conditioned room with their forearms uncovered to let the skin adapt to the temperature (22°C ± 2°C) and humidity (50% ± 2%) of the room. Skin hydration and skin occlusion were recorded at day one (before treatment) and day seven (after treatment). Three measurements for skin hydration and skin occlusion were performed in each testing area. Results NLC formulations with the highest lipid concentration, highest solid lipid concentration, and additional propylene glycol (formulations A1, A2, and A5) showed higher physical stability than other formulations. The addition of propylene glycol into an NLC system helped to reduce the particle size of the NLC and enhanced its long-term physical stability. All the NLC formulations were found to significantly increase skin hydration compared to the untreated controls within 7 days. All NLC formulations exhibited occlusive properties as they reduced the transepidermal water loss within 7 days. This effect was more pronounced with the addition of propylene glycol or lecithin into an NLC formulation, whereby at least 60% reduction in transepidermal water loss was observed. Conclusion NLCs with high lipid content, solid lipid content, phospholipid, and lecithin are a highly effective cosmetic delivery system for cosmetic topical applications that are designed to boost skin hydration. PMID:23293516

  18. Management of myofascial pain: low-level laser therapy versus occlusal splints.

    PubMed

    Öz, Selcen; Gökçen-Röhlig, Bilge; Saruhanoglu, Alp; Tuncer, Erman Bülent

    2010-11-01

    The present study was designed to compare the effects of low-level laser with occlusal splints in patients with signs and symptoms of myofascial pain (MP) dysfunction syndrome. A total of 40 (34 women and 6 men, with a mean age of 32.84 [SD, 10.70] years) were selected after the diagnosis of MP according to the Research Diagnostic Criteria for Temporomandibular Disorder. The patients were randomly divided into 2 groups: study group (n = 20) and control group (n = 20). Low-level laser was applied to patients in the study group 2 times per week, for a total of 10 sessions. Patients in the control group were instructed to wear occlusal splints 24 h/d for 3 months. The functional examination was based on Research Diagnostic Criteria for Temporomandibular Disorder and pressure pain threshold values were obtained with the aid of an algometer in both groups. Patients' self-report of pain was evaluated with visual analog scale. Comparisons were made within and between the groups before and after treatment. Vertical movements showed statistically significant improvements after the treatments in both groups (P < 0.01), but when the groups were compared with each other, there were no significant difference between the groups. In both groups, tenderness to palpation of the muscles decreased significantly. Pressure pain threshold evaluations and visual analog scale scores revealed similar results, too. This particular type of low-level laser therapy (820 nm, 3 J/cm2, 300-mW output power) is as effective as occlusal splint in pain release and mandibular movement improvement in MP. PMID:21119408

  19. 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.

  20. Limb suction evoked during arterial occlusion causes systemic sympathetic activity in humans.

    PubMed

    Cui, Jian; Blaha, Cheryl; Herr, Michael D; Drew, Rachel C; Muller, Matthew D; Sinoway, Lawrence I

    2015-09-01

    Venous saline infusions in an arterially occluded forearm evokes reflex increases in muscle sympathetic nerve activity (MSNA) and blood pressure (BP). We hypothesized that the application of suction to the human limbs would activate this venous distension reflex and raise sympathetic outflow. We placed airtight pressure tanks and applied 100 mmHg negative pressure to an arterially occluded limb (occlusion and suction, O&S) to induce tissue deformation without fluid translocation. BP, heart rate (HR), and MSNA were assessed in 19 healthy subjects during 2 min of arm or leg O&S. Occlusion without suction served as a control. During a separate visit, saline (5% forearm volume) was infused into veins of the arterially occluded arm (n = 13). The O&S increased limb circumference, MSNA burst rate (arm: Δ6.7 ± 0.7; leg: Δ6.8 ± 0.7 bursts/min), and total activity (arm: Δ199 ± 14; leg: Δ172 ± 22 units/min) and BP (arm: Δ4.3 ± 0.3; leg: Δ9.4 ± 1.4 mmHg) from the baseline. The MSNA and BP responses during arm O&S correlated with those during leg O&S. Occlusion alone had no effect on MSNA and BP. MSNA (r = 0.607) responses during arm O&S correlated with those evoked by the saline infusion into the arm. These correlations suggest that sympathetic activation during limb O&S is likely, at least partially, to be evoked via the venous distension reflex. These data suggest that suction of an occluded limb evokes sympathetic activation and that the limb venous distension reflex exists in arms and legs of normal humans. PMID:26136530

  1. Limb suction evoked during arterial occlusion causes systemic sympathetic activity in humans

    PubMed Central

    Cui, Jian; Blaha, Cheryl; Herr, Michael D.; Drew, Rachel C.; Muller, Matthew D.

    2015-01-01

    Venous saline infusions in an arterially occluded forearm evokes reflex increases in muscle sympathetic nerve activity (MSNA) and blood pressure (BP). We hypothesized that the application of suction to the human limbs would activate this venous distension reflex and raise sympathetic outflow. We placed airtight pressure tanks and applied 100 mmHg negative pressure to an arterially occluded limb (occlusion and suction, O&S) to induce tissue deformation without fluid translocation. BP, heart rate (HR), and MSNA were assessed in 19 healthy subjects during 2 min of arm or leg O&S. Occlusion without suction served as a control. During a separate visit, saline (5% forearm volume) was infused into veins of the arterially occluded arm (n = 13). The O&S increased limb circumference, MSNA burst rate (arm: Δ6.7 ± 0.7; leg: Δ6.8 ± 0.7 bursts/min), and total activity (arm: Δ199 ± 14; leg: Δ172 ± 22 units/min) and BP (arm: Δ4.3 ± 0.3; leg: Δ9.4 ± 1.4 mmHg) from the baseline. The MSNA and BP responses during arm O&S correlated with those during leg O&S. Occlusion alone had no effect on MSNA and BP. MSNA (r = 0.607) responses during arm O&S correlated with those evoked by the saline infusion into the arm. These correlations suggest that sympathetic activation during limb O&S is likely, at least partially, to be evoked via the venous distension reflex. These data suggest that suction of an occluded limb evokes sympathetic activation and that the limb venous distension reflex exists in arms and legs of normal humans. PMID:26136530

  2. 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 ...

  3. History of materials used for recording static and dynamic occlusal contact marks: a literature review

    PubMed Central

    Rahul, G R.; Poduval, Soorya T.; Shetty, Karunakar; Gupta, Bhawna; Rajora, Varun

    2013-01-01

    In the discipline of prosthetic dentistry it is important not only to examine the occlusion, but to be able to record, store, and transfer the information. Over the years many occlusion testing materials have been used. It has been suggested the clinical recording and transfer of information using waxes and other occlusion recording materials have disadvantages relating to inaccuracy and problems of manipulation. Therefore, there has been introduction of many new systems for recording occlusion contacts to overcome such problems. The correct physiological recovery of occlusion posses as much a challenge as ever for every dentist and technician. Even the smallest high spots measuring just a few microns can cause dysfunctions like temporo-mandibular pain. Occlusal proportions are being constantly changed with every procedure. Therefore, an understanding of the synergy of the teeth in static and dynamic occlusion forms the basis of good dentistry. The purpose of this review article is to give and overview of the various materials and methods that have been used to record occlusal contact marks. Key words:Occlusal contact marks, Occlusion indicators, Occlusion test materials, Occlusion recording materials. PMID:24455051

  4. Tissue microcirculation measured by vascular occlusion test during anesthesia induction.

    PubMed

    Kim, Tae Kyong; Cho, Youn Joung; Min, Jeong Jin; Murkin, John M; Bahk, Jae-Hyon; Hong, Deok Man; Jeon, Yunseok

    2016-02-01

    Tissue microcirculation measured by vascular occlusion test is impaired during septic shock. However, it has not been investigated extensively during anesthesia induction. The aim of the study is to evaluate tissue microcirculation during anesthesia induction. We hypothesized that during anesthesia induction, tissue microcirculation measured by vascular occlusion test might be enhanced with peripheral vasodilation during anesthesia induction. We conducted a prospective observational study of 50 adult patients undergoing cardiac surgery. During anesthesia induction, we measured and analyzed tissue oxygen saturation, vascular occlusion test, cerebral oximetry, forearm-minus-fingertip skin temperature gradients and hemodynamic data in order to evaluate microcirculation as related to alterations in peripheral vasodilation as reflected by increased Tforearm-finger thermal gradients. During anesthesia induction, recovery slope during vascular occlusion test and cerebral oxygen saturation increased from 4.0 (1.5) to 4.7 (1.3) % s(-1) (p = 0.02) and 64.0 (10.2) to 74.2 (9.2) % (p < 0.001), respectively. Forearm-minus-fingertip skin temperature gradients decreased from 1.9 (2.9) to -1.4 (2.2) °C (p < 0.001). There was an inverse correlation between changes in the skin temperature gradients and changes in cerebral oximetry (r = 0.33; p = 0.02). During anesthesia induction, blood pressure and forearm-minus-fingertip skin temperature gradients decrease while cerebral oximetry and vascular occlusion test recovery slope increase. These findings suggest that anesthesia induction increases tissue microcirculation with peripheral vasodilation. PMID:25750016

  5. Sclerostin is essential for alveolar bone loss in occlusal hypofunction

    PubMed Central

    XU, YANG; WANG, LUFEI; SUN, YAO; HAN, XIANGLONG; GAO, TIAN; XU, XIN; CHEN, TIAN; ZHAO, XUEFENG; ZENG, HUAN; WANG, YANMIN; BAI, DING

    2016-01-01

    Bone loss is caused by occlusal hypofunction and is a serious health concern. This is particularly true of tooth loss, which is common in the elderly. However, the cellular and molecular mechanisms underlying bone loss have yet to be fully elucidated. Sclerostin and Wnt/β-catenin signaling have previously been reported to serve important roles in regulating bone remodeling. Therefore, the present study aimed to investigate the involvement of sclerostin and Wnt/β-catenin signaling in occlusal hypofunction-induced alveolar bone remodeling. The unilateral maxillary molars of 14 male Sprague-Dawley rats were extracted in order to establish a model of occlusal hypofunction. For each rat, the non-extraction side was treated as the control group for comparisons with the extraction side. At 8 weeks after tooth extraction, the rats were sacrificed and alveolar bone specimens were harvested for X-ray radiography, micro-computed tomography (CT) and histological and immunohistochemical examinations. Bone loss and architecture deterioration were observed at the occlusal hypofunction side. The bone mineral density was markedly decreased and the ratio of bone volume to total volume was significantly decreased at the hypofunction side, as compared with the control side (P<0.001). In addition, the number of osteoclasts at the hypofunction side were significantly increased compared with that in the control side (P<0.001), as demonstrated using tartrate-resistant acid phosphatase staining. Furthermore, the protein expression levels of sclerostin and receptor activator of nuclear factor-κB ligand were increased, whereas those of β-catenin were decreased, at the hypofunction side when compared with the control side. In conclusion, the results of the present study suggested that occlusal hypofunction-induced bone loss may be associated with upregulated expression of sclerostin, which, in turn, may inhibit the activity of the Wnt/β-catenin signaling pathway. PMID:27168809

  6. Effects of bronchoconstriction and external resistive loading on the sensation of dyspnea.

    PubMed

    Taguchi, O; Kikuchi, Y; Hida, W; Iwase, N; Satoh, M; Chonan, T; Takishima, T

    1991-12-01

    To determine whether the intensity of dyspnea at a given level of respiratory motor output differs between bronchoconstriction and the presence of an external resistance, we compared the sensation of difficulty in breathing during isocapnic voluntary hyperventilation in six normal subjects. An external resistance of 1.9 cmH2O.1-1.s was applied during both inspiration and expiration. To induce bronchoconstriction, histamine aerosol (5 mg/ml) was inhaled until airway resistance (Raw) increased to a level approximately equal to the subject's control Raw plus the added external resistance. To clarify the role of vagal afferents on the genesis of dyspnea during both forms of obstruction to airflow, the effect of airway anesthesia by lidocaine aerosol inhalation was also examined after histamine and during external resistive loading. The sensation of difficulty in breathing was rated at 30-s intervals on a visual analog scale during isocapnic voluntary hyperpnea, in which the subjects were asked to copy an oscilloscope volume trace obtained previously during progressive hypercapnia. Histamine inhalation significantly increased the intensity of the dyspneic sensation over the equivalent external resistive load at the same levels of ventilation and occlusion pressure during voluntary hyperpnea. Inhaled lidocaine decreased the sensation of dyspnea during bronchoconstriction with no change in Raw, but it did not significantly change the sensation during external resistive loading. These results suggest that afferent vagal activity plays a role in the genesis of dyspnea during bronchoconstriction. PMID:1778911

  7. 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.

  8. 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.

  9. Neuroprotective efficacy of lifarizine (RS-87476) in a simplified rat survival model of 2 vessel occlusion.

    PubMed Central

    McBean, D. E.; Winters, V.; Wilson, A. D.; Oswald, C. B.; Alps, B. J.; Armstrong, J. M.

    1995-01-01

    1. A new, modified rat two vessel occlusion model (with hypotension) was established and the neuroprotective efficacy of the novel agent lifarizine (RS-87476) was examined. 2. The two vessel occlusion model used in the study was a modification of the model described in the literature, whereby we have obviated the need to use a muscle relaxant and intubate the trachea to provide ventilatory support by providing a tight fitting face mask attached to the ventilator. Furthermore, the need to combine exsanguination and additional pharmacological means of inducing the mandatory hypotension (50 mmHg), required to decrease brain blood perfusion pressure, has been removed by simply manipulating the concentration of the already present halothane anaesthetic. 3. The appropriate level of hypotension having been reached, microvascular clips were applied to bilaterally occlude the common carotid arteries for 12 min. This resulted in a loss of the cortical EEG activity. Local cerebral blood flow was measured 6 min into the occlusion period, using the fully quantitative [14C]-iodoantipyrine autoradiographic technique, in a separate group of rats (n = 5). This illustrated the lack of any blood flow, in the areas under study, during the period when there was an isoelectric cortical EEG pattern. 4. The high grade global ischaemic lesion which occurred gave quantifiable neuronal damage in several vulnerable regions of the brain, namely, the hippocampal CA1 sub-field, cortex, thalamus, striatum, and cerebellar brain stem (Purkinje cells). 5. Following the global ischaemic insult the rats were allowed to recover for 72 h before assessment of the damage, during which time one group of rats (n = 11) received 100 micrograms kg-1 lifarizine i.a. 5 min post-occlusion, 500 micrograms kg-1 lifarizine i.p. 15 min post-occlusion, and 500 micrograms kg-1 lifarizine i.p. twice daily for 72 h. A second group of rats (n = 12) was treated with appropriate volumes of vehicle (0.4 ml kg-1 i.a. and 2 ml

  10. 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

  11. Effects of bioactive glass with and without mesoporous structures on desensitization in dentinal tubule occlusion

    NASA Astrophysics Data System (ADS)

    Chen, Wen-Cheng; Kung, Jung-Chang; Chen, Cheng-Hwei; Hsiao, Yu-Cheng; Shih, Chi-Jen; Chien, Chi-Sheng

    2013-10-01

    Bioactive glass (BG) is a potential material for treating dentin hypersensitivity due to its high ability of dissolution. In this study, conventional BG and BG with well-ordered mesopore structures (MBG) were applied for dentinal tubule occlusion. We used X-ray diffractometer (XRD), scanning electronic microscope (SEM), and Fourier transform infrared (FTIR) to investigate the physiochemical properties and the dentinal tubule occlusion ability of BG and MBG groups. The results showed that the major crystallite phase of MBG and BG agents was monocalcium phosphate monohydrate. MBG pastes, mixed with 30 and 40 wt% phosphoric acid hardening solutions, had the ability to create a penetration depth greater than 50 μm. These results showed that BG with mesoporous structures turned the pastes mixed with suitable phosphoric acid solution into a material with great ability for occluding dentinal tubules; it has a short reaction time and good operability, and these agents have better potential for the treatment of dentin hypersensitivity than BG without mesoporous structures.

  12. Automatically Detect and Track Multiple Fish Swimming in Shallow Water with Frequent Occlusion

    PubMed Central

    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. PMID:25207811

  13. 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…

  14. 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.

  15. 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.

  16. Transcutaneous pO2 measurement during tourniquet-induced venous occlusion using dynamic phosphorescence imaging.

    PubMed

    Geis, S; Babilas, P; Schreml, S; Angele, P; Nerlich, M; Jung, E M; Prantl, L

    2008-01-01

    A sufficient oxygen supply in skin grafts requires a functioning microcirculation. Venous occlusion impairs the microcirculation and is therefore a major threat of healing. Luminescence life time imaging (LLI) enables the non-invasive and two-dimensional assessment of the transcutaneous oxygen partial pressure (p(tc)O2). In the current trial this new device was applied for monitoring of venous congestion. A tourniquet on the upper arm was inflated up to 40-50 mmHg and released after 10 min in eight healthy volunteers. The p(tc)O2 was measured at the lower arm every minute prior to, during and up to 10 min after cuff occlusion (40 degrees C applied skin temperature) using LLI of platinum(II)-octaethyl-porphyrin immobilized in a polystyrene matrix. For validation the polarographic Clark electrode technique was applied in close proximity and measurement was performed simultaneously. p(tc)O2 measurements prior to (Clark: 50.68+/-5.69 mmHg vs. LLI: 50.89+/-4.96 mmHg) and at the end of the venous congestion (Clark: 16.41+/-4.54 mmHg vs. LLI: 23.82+/-3.23 mmHg) did not differ significantly using the Clark electrode vs. LLI. At the initial congestion respectively reperfusion phase the Clark electrode measured faster decreases respectively increase of p(tc)O2 due to oxygen consumption of this method. This experimental trial demonstrates the applicability of LLI to quantify the p(tc)O2 under changing venous blood flow. The use of planar transparent sensors allows the non-invasive generation of two-dimensional maps of surface pO2 what makes this method particular suitable for monitoring of skin grafts. PMID:19126987

  17. Predictors and Periprocedural Myocardial Injury Rate of Small Side Branches Occlusion in Coronary Bifurcation Intervention

    PubMed Central

    Zhang, Dong; Xu, Bo; Yin, Dong; Li, Yiping; He, Yuan; You, Shijie; Qiao, Shubin; Wu, Yongjian; Yan, Hongbing; Yang, Yuejin; Gao, Runlin; Dou, Kefei

    2015-01-01

    Abstract Occlusion of small side branch (SB) may result in significant adverse clinical events. We aim to characterize the predictors of small SB occlusion and incidence of periprocedural myocardial injury (PMI) in coronary bifurcation intervention. Nine hundred twenty-five consecutive patients with 949 bifurcation lesions (SB ≤ 2.0 mm) treated with percutaneous coronary intervention (PCI) were studied. All clinical characteristics, coronary angiography findings, PCI procedural factors, and quantitative coronary angiographic analysis data were collected. SB occlusion after main vessel (MV) stenting was defined as no blood flow or any thrombolysis in myocardial infarction (TIMI) flow grade decrease in SB after MV stenting. Multivariate logistic regression analysis was performed to identify independent predictors of small SB occlusion. Creatine kinase-myocardial band activity was determined by using an immunoinhibition assay and confirmed by mass spectrometry. Incidence of PMI between no SB occlusion group and SB occlusion group was compared. SB occlusion occurred in 86 (9.1%) of 949 bifurcation lesions. Of SB occlusion, total occlusion occurred in 64 (74.4%) lesions and a decrease in TIMI flow occurred in 22 (25.6%) lesions. True bifurcation lesion, irregular plaque, predilation in SB, preprocedural SB TIMI flow grade, preprocedural diameter stenosis of distal MV, preprocedural diameter stenosis of bifurcation core, bifurcation angle, diameter ratio between MV and SB, diameter stenosis of SB before MV stenting, and MV lesion length were independent risk factors of SB occlusion. We observed a significantly higher incidence of PMI in each cutoff level in patients with SB occlusion compared with those without SB occlusion. True bifurcation lesion, irregular plaque, and 8 other predictors were independent predictors of SB occlusion. Patients with small SB occlusion had significant higher incidence of PMI. PMID:26107685

  18. 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.

  19. Relation between retinal vein occlusions and axial length.

    PubMed Central

    Aritürk, N.; Oge, Y.; Erkan, D.; Süllü, Y.; Mohajerý, F.

    1996-01-01

    AIMS: To evaluate the ocular axial length as a risk factor for development of central retinal vein occlusion (CRVO) and branch retinal vein occlusion (BRVO). METHODS: Ocular axial lengths were measured, by A-scan ultrasonography, in 17 patients with CRVO and 41 patients with BRVO and compared with those of contralateral unaffected eyes and 66 age matched controls. RESULTS: In 17 patients with CRVO the mean axial length of affected eyes was 22.25 (SD 0.19) mm and of unaffected eyes was 22.61 (0.13) mm. In 41 patients with BRVO the mean axial length of affected eyes was 22.89 (0.11) mm and of unaffected eyes was 22.99 (0.12) mm. CONCLUSION: These findings confirm that the axial lengths in CRVO and BRVO were significantly shorter than in the controls. This significant difference may be a risk factor in the development of CRVO and BRVO. PMID:8795376

  20. Left Subclavian Artery Occlusion: Femoro-Axillary Artery Retrograde Bypass

    PubMed Central

    Nakashima, Masaya; Kobayashi, Hideaki; Kobayashi, Masayoshi

    2016-01-01

    The treatment tactics for subclavian artery occlusion include the more commonly used endovascular therapy rather than surgical intervention. We present a case of a 61-year-old woman with dialysis-dependent chronic renal failure who experienced left finger necrosis in the left upper extremity. To salvage the limb, we performed femoro-axillary (fem-ax) artery bypass using an autologous saphenous vein graft. However, 10 months later, she experienced coldness in the left forearm. Angiography revealed chronic total occlusion of the venous bypass. Despite emergent thrombectomy, redo fem-ax artery bypass operation was performed using a prosthetic graft. Upper limb salvage can be achieved by fem-ax artery retrograde bypass. PMID:27386454

  1. A rare case of branch retinal vein occlusion following Sirsasana.

    PubMed

    Balamurugan, Anugraha; Srikanth, Krishnagopal

    2016-01-01

    Sirsasana is a type of headstand postural yoga in which the body is completely inverted. It is performed with or without wall support. In this position, the body is held upright supported by the forearms, while the crown of the head rests lightly on the floor. This is an advanced pose and should be attempted under the supervision of a qualified yoga instructor. The practice of Sirsasana is postulated to increase blood flow to the brain, improving memory, and other intellectual functions. It is also known to cause causes raised intraocular pressure, decompression retinopathy, glaucomatous visual field defects, central retinal vein occlusion, progression of glaucoma, optic neuropathy, and conjunctival varix thrombosis. We report a case of branch retinal vein occlusion following Sirsasana in a patient with systemic hypertension. PMID:27512326

  2. A rare case of branch retinal vein occlusion following Sirsasana

    PubMed Central

    Balamurugan, Anugraha; Srikanth, Krishnagopal

    2016-01-01

    Sirsasana is a type of headstand postural yoga in which the body is completely inverted. It is performed with or without wall support. In this position, the body is held upright supported by the forearms, while the crown of the head rests lightly on the floor. This is an advanced pose and should be attempted under the supervision of a qualified yoga instructor. The practice of Sirsasana is postulated to increase blood flow to the brain, improving memory, and other intellectual functions. It is also known to cause causes raised intraocular pressure, decompression retinopathy, glaucomatous visual field defects, central retinal vein occlusion, progression of glaucoma, optic neuropathy, and conjunctival varix thrombosis. We report a case of branch retinal vein occlusion following Sirsasana in a patient with systemic hypertension. PMID:27512326

  3. Occlusion-capable multiview volumetric three-dimensional display

    NASA Astrophysics Data System (ADS)

    Cossairt, Oliver S.; Napoli, Joshua; Hill, Samuel L.; Dorval, Rick K.; Favalora, Gregg E.

    2007-03-01

    Volumetric 3D displays are frequently purported to lack the ability to reconstruct scenes with viewer-position-dependent effects such as occlusion. To counter these claims, a swept-screen 198-view horizontal-parallax-only 3D display is reported here that is capable of viewer-position-dependent effects. A digital projector illuminates a rotating vertical diffuser with a series of multiperspective 768×768 pixel renderings of a 3D scene. Evidence of near-far object occlusion is reported. The aggregate virtual screen surface for a stationary observer is described, as are guidelines to construct a full-parallax system and the theoretical ability of the present system to project imagery outside of the volume swept by the screen.

  4. 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

  5. Promoter occlusion: transcription through a promoter may inhibit its activity.

    PubMed

    Adhya, S; Gottesman, M

    1982-07-01

    Induction of prophage lambda inhibits the expression of the gal operon from its cognate promoters. The effect is observed only in cis, and is due to frequent transcription of the gal promoter region by RNA polymerase molecules initiating upstream at the prophage PL promoter. The frequency of transcription initiation at PL is some 30 times greater than that at the gal promoter, Pg1. PL is one of the strongest procaryotic promoters. This "promoter occlusion" is essentially complete when the distance between gal and PL is small (less than or equal to 10 kb); and when PL is fully active (that is, in the absence of the cl or cro repressors). We discuss the possibility that promoter occlusion at two lambda promoters, Pint and PR', might play a role in the sequential expression of viral functions. PMID:6217898

  6. Recognition of Simple 3D Geometrical Objects under Partial Occlusion

    NASA Astrophysics Data System (ADS)

    Barchunova, Alexandra; Sommer, Gerald

    In this paper we present a novel procedure for contour-based recognition of partially occluded three-dimensional objects. In our approach we use images of real and rendered objects whose contours have been deformed by a restricted change of the viewpoint. The preparatory part consists of contour extraction, preprocessing, local structure analysis and feature extraction. The main part deals with an extended construction and functionality of the classifier ensemble Adaptive Occlusion Classifier (AOC). It relies on a hierarchical fragmenting algorithm to perform a local structure analysis which is essential when dealing with occlusions. In the experimental part of this paper we present classification results for five classes of simple geometrical figures: prism, cylinder, half cylinder, a cube, and a bridge. We compare classification results for three classical feature extractors: Fourier descriptors, pseudo Zernike and Zernike moments.

  7. Facial height in Japanese-Brazilian descendants with normal occlusion

    PubMed Central

    Vieira, Fabiano Paiva; Pinzan, Arnaldo; Janson, Guilherme; Fernandes, Thais Maria Freire; Sathler, Renata Carvalho; Henriques, Rafael Pinelli

    2014-01-01

    OBJECTIVE: The aim of this study was to determine the standards of facial height in 30 young (14-year-old) Japanese-Brazilian descendants with normal occlusion, and assess whether sexual dimorphism is evident. METHODS: The cephalometric measurements used followed the analyses by Wylie-Johnson, Siriwat-Jarabak, Gebeck, Merrifield and Horn. RESULTS: Results showed dimorphism for total anterior facial height (TAFH), lower anterior facial height (LAFH), anterior facial height (AFH), total posterior facial height (TPFH) and upper posterior facial height (UPFH) measurements. CONCLUSIONS: The standards of facial heights in young Japanese-Brazilian descendants with normal occlusion were observed. Sexual dimorphism was identified in five out of thirteen evaluated variables at this age range. PMID:25715717

  8. 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

  9. Internal carotid pseudo-occlusion: early and late results.

    PubMed

    Pulli, R; Frosini, P; Gatti, M; Narcetti, S; Bernacchi, R; Pratesi, C

    1997-02-01

    Internal carotid pseudo-occlusion (ICP) is a pathology of difficult diagnostic evaluation and treatment in the group of extracranial carotid diseases. The authors report the results of 24 ICP(S) surgically treated in the last five years. No perioperative death was reported. The neurological morbility rate was as low as 4% (1/24), which is quite a good results for this high-risk pathology. Clinical and instrumental follow-up was performed (at 1-3-6-12-24 months from surgery). Six early asymptomatic thromboses (25%) were observed, and the remaining patients showed patent vessels and no symptoms at all. In conclusion surgical treatment of ICP is often able to prevent cerebral ischaemia, and the high rate of early occlusion should not limit surgical indication. PMID:9128116

  10. Paraplegia due to Acute Aortic Coarctation and Occlusion

    PubMed Central

    Park, Chang-Bum; Kim, Min-Ki; Kim, Sang-Hyun

    2014-01-01

    Coarctation and occlusion of the aorta is a rare condition that typically presents with hypertension or cardiac failure. However, neuropathy or myelopathy may be the presenting features of the condition when an intraspinal subarachnoid hemorrhage has compressed the spinal cord causing ischemia. We report two cases of middle-aged males who developed acute non-traumatic paraplegia. Undiagnosed congenital abnormalities, such as aortic coarctation and occlusion, should be considered for patients presenting with nontraumatic paraplegia in the absence of other identifiable causes. Our cases suggest that spinal cord ischemia resulting from acute spinal subarachnoid hemorrhage and can cause paraplegia, and that clinicians must carefully examine patients presenting with nontraumatic paraplegia because misdiagnosis can delay initiation of the appropriate treatment. PMID:24851152

  11. 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.

  12. Deaths from Occlusive Arterial Disease in Renal Allograft Recipients

    PubMed Central

    Ibels, L. S.; Stewart, J. H.; Mahony, J. F.; Sheil, A. G. R.

    1974-01-01

    In a series of 325 recipients of cadaveric renal transplants sudden occlusive arterial disease was found to be responsible for 12% of deaths. Acute myocardial infarction (9%) occurred 25 times more than expected in the normal population and cerebral thrombosis (3%) 300 times more. The greatest loss was in the initial three-month period after transplantation. Patients with renal failure due to essential hypertension were especially at risk, accounting for six of the 12 deaths. PMID:4606408

  13. Feasibility of laser targeted photo-occlusion of ocular vessels.

    PubMed Central

    Asrani, S; Zeimer, R

    1995-01-01

    AIMS/BACKGROUND--Neovascularisation occurs in many major ocular diseases such as diabetes, age-related macular degeneration, and sickle cell disease. Laser photocoagulation is typically used to obliterate the vessels but it also causes severe damage to adjacent normal tissues. This is a very significant limitation especially in the treatment of choroidal neovascularisation which often covers large areas of the posterior pole and the fovea. A method, laser targeted delivery, has been developed capable of releasing drugs locally and non-invasively in the choroidal or retinal vasculature. This method could be used to target a photo-sensitiser to neovascular membranes and cause their selective occlusion by irradiating them. The targeting properties of the method promise to yield a treatment for neovascularisation that does not damage adjacent tissues and thus preserves vision. The purpose of the present study was to test the feasibility of occluding ocular vessels with this method. METHOD--The iris vessels of the albino rat were chosen because the treatment could be assessed unequivocally and followed with time. Aluminium phthalocyanine tetrasulphonate was encapsulated in heat sensitive liposomes and administered systemically. The iris vessels were irradiated with a yellow laser to raise their temperature to 41 degrees C, cause a phase transition in the liposomes and thereby locally release the photosensitiser. The laser was also used to excite the released photosensitiser and cause occlusion. The effect was monitored immediately and for 8 months thereafter. Controls for the effect of the laser and the unencapsulated drug were conducted. RESULTS--The results demonstrated that occlusion can be achieved and sustained for the period of follow up. The controls showed that the effect was not due to heat or to the activation of the low dose of free drug. CONCLUSION--These preliminary findings indicate that laser targeted photo-occlusion is a promising new method for the

  14. 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.

  15. 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. PMID:26670911

  16. 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. PMID:25481219

  17. 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.

  18. Retinal vein occlusions: a review for the internist.

    PubMed

    Marcucci, Rossella; Sofi, Francesco; Grifoni, Elisa; Sodi, Andrea; Prisco, Domenico

    2011-08-01

    Retinal vein occlusion (RVO) is a disease that is often associated with a variety of systemic disorders including arterial hypertension, diabetes mellitus, dyslipidemia and systemic vasculitis. There are various types of RVO, categorized on the basis of the site of occlusion and on the type of consequent vascular damage. Central retinal vein occlusion (CRVO) is the most clinically relevant type of RVO. In addition to well-known classical risk factors, new thrombophilic factors have been investigated in patients with RVO. Data concerning a number of the parameters remain contradictory; yet, hyperhomocysteinemia and vitamins involved in methionine metabolism appear to play a significant role in the pathogenesis of this disease. Alterations in the fibrinolysis pathway (elevated levels of PAI-1 and Lipoprotein (a)), together with haemorheologic modifications have been recently consistently associated with the disease. Medical treatment includes identification and correction of vascular risk factors. In addition, LMWHs appear to be the best therapeutic approach even if based on a limited number of trials, conducted on a limited number of patients. No data are available on the possible role of antithrombotic strategies in the long-term prevention of recurrent RVO or vascular events. PMID:21547483

  19. 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. PMID:27115522

  20. 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.

  1. A Novel Canine Model of Acute Vertebral Artery Occlusion

    PubMed Central

    Zhang, Yunfeng; Jin, Min; Du, Bin; Lin, Hao; Xu, Chengyong; Jiang, Weijian; Jia, Jianping

    2015-01-01

    Background The extended time window and theoretic reduction in hemorrhage make mechanical strategies an attractive approach for the treatment of patients with ischemic stroke. However, a limited availability of suitable animal models of cerebrovascular thrombosis has hampered the study of novel endovascular interventions. The aim of the present study was to develop a new technique for site-specific placement of a thrombus in a canine model that would allow for the evaluation of mechanical thrombectomy and clot retrieval methods and the visualization of thrombus dislocation or fragmentation during angiographic manipulation. Methods Angiography and embolization with a preformed thrombus were performed in 12 canines. Under fluoroscopic guidance, an embolism protection device (EPD) was anchored to the middle segment of the left vertebral artery (VA) via the left femoral arterial sheath. A preformed radiopaque clot was injected through the guide catheter into the left VA, via the contralateral femoral artery, proximal to the EPD. After 15 min of occlusion, the EPD was removed and persistent occlusion of the VA was documented angiographically. Results Angiography performed during the observation period confirmed the persistence of VA occlusion in each case, and displacement of the radiopaque clots did not occur during the 3-hour observation period. The technique allowed selective embolization of targeted vessels without thrombus fragmentation. Conclusion This study demonstrates, for the first time, a canine model of post-circulation embolism induced by autologous blood clot placement. This model can be rapidly formed and easily operated, and the site of thrombosis can be readily controlled. PMID:26545253

  2. Laparoscopic uterine artery occlusion combined with myomectomy for uterine myomas.

    PubMed

    Cheng, Zhongping; Yang, Weihong; Dai, Hong; Hu, Liping; Qu, Xiaoyan; Kang, Le

    2008-01-01

    We sought to evaluate the clinical feasibility and mid- to long-term effects of laparoscopic uterine artery occlusion before myomectomy in the treatment of uterine myomas. A total of 566 patients with uterine myoma were treated by laparoscopic uterine artery occlusion before myomectomy from October 2001 through July 2007. Mean blood loss was 88.2 +/- 52.7 mL (95% CI 82.7-93.8). The highest postoperative temperature was 37.8 +/- 0.3 degrees C, and the postoperative morbidity was 5.7% (32/566). Number of days to the return of bowel movement was 1.9 +/- 0.5d and in hospital stay after surgery was 7.7 +/- 2.5d. Complications included 2 instances of subcutaneous emphysema, 1 of vaginal bleeding, and 3 of mild intestinal obstruction. At a median of 26.3 months (range 6-69 months) of follow-up, the rate of myoma recurrence was 3.0% (15/517), uterus volume reduction was 48.9%, and correction of menstruation abnormality was 97.1% (502/517). Laparoscopic uterine artery occlusion before myomectomy can expand myomectomy indications with better results. PMID:18439509

  3. NONICHEMIC CENTRAL RETINAL VEIN OCCLUSION ASSOCIATED WITH HEREDITARY THROMBOPHYLIA.

    PubMed

    Fişuş, Andreea Dana; Pop, Doina Suzana; Rusu, Monica Blanka; Vultur, Florina; Horvath, Karin Ursula

    2015-01-01

    Retinal vein occlusion (RVO) is the second most common retinal vein disease with significant visual loss via thrombus or compression of vein wall. Thrombophilia is the predisposition to vascular thrombosis with the existence of genetic defect that leads to blood hypercoagulability. This report describes the case of a 55 year old male patient, with an active life who presented himself at the emergency room with acute visual lose, insidious and progressive visual field constriction, without any known history of neurological or vascular diseases. The examinations revealed unilateral optic nerve head edema, the fluorescein angiography was specific for nonischemic central retinal vein occlusion CRVO complicated with macular edema. Blood examinations has emphasized the presence of the heterozygous mutation A1298C in the methylenetetrahydrofolate reductase gene (MTHFR), the only one presented from the thrombophilia screen panel and a slightly elevated cholesterol level. During the follow-up period, the patient received anti-VEGF treatment (Bevacizumab, 3x 0.1 ml intravitreal injections) with improved visual acuity and amendment of macular edema. The complex etiology calls for interdisciplinary approach to determine better the cause of this ophthalmological disease. Although studies have found a correlation between some thrombophilia mutations and retinal vein occlusion, more studies that contain a larger number of patients are necessary in order to determine the final role of these gene variants. PMID:26978887

  4. Early results of pulsed dye laser angioplasty with integral ball-tips in long femoral occlusions

    NASA Astrophysics Data System (ADS)

    Murray, Alan; Mitchell, David C.; Wood, Richard F. M.

    1990-07-01

    A Pulsed Dye laser together with specifically designed integral ball-tipped optical fibres have been used for the primary recanalisation of femoropopliteal vascular disease in 25 limbs of 23 patients. All patients had complete occlusions of the vessels ranging from 8-49cms in length (mean 22cms), having presented with critical ischaemia (18) or severe claudication warranting operative intervention (5). Pedal ulceration was present in 8 limbs and digital gangrene in 4. The laser produced visible light at 480nm in lOOmJ/lus pulses, at a frequency of 10-20Hz. The energy delivery device comprised a smooth atraumatic ball-tip constructed from the glass of the optical fibre, which was loaded retrogradely into a standard balloon angioplasty catheter. The device was introduced through a common femoral artery cutdown. Angiographic recanalisation was achieved in 22 of the 25 limbs with a mean energy of 280J(range 68-727J) and in each case the channel created by the laser fibre was augmented by balloon angioplasty. Technical failure occurred in three cases, caused by a wall dissection, persistent side-branch entry and incomplete lesion penetration respectively. Eighteen of procedures (72%) were clinically successful with marked symptomatic improvement. Of the four angiographic successful but clinical failures, acute occlusion within 48 hours occurred in 2 diabetic patients with very poor run-off and distal gangrene. The third case failed acutely due to a technically inadequate balloon dilatation and the fourth patient failed to improve symptomatically due to widespread with segmental tibial vessel disease below a successful recanalisation. Over a mean follow-up period of 7 months, three patients died of myocardial infarction. Twelve of the 23 patients (52%) remain well with patent vessels. These early results demonstrate the efficacy of pulsed dye laser angioplasty using ball-tipped optical fibres.

  5. TRANSITION TO COLLATERAL FLOW AFTER ARTERIAL OCCLUSION PREDISPOSES TO CEREBRAL VENOUS STEAL

    PubMed Central

    Pranevicius, Osvaldas; Pranevicius, Mindaugas; Pranevicius, Henrikas; Liebeskind, David S.

    2011-01-01

    Introduction Stroke related tissue pressure increase in the core (Pcore) and penumbra (Ppen) determines regional cerebral perfusion pressure (rCPP) defined as a difference between local inflow pressure (Pi) and venous (Pv) or tissue pressure, whichever is higher. We previously showed that venous pressure reduction below the Pcore causes blood flow diversion - cerebral venous steal. Now we investigated how transition to collateral circulation after complete arterial occlusion affects rCPP distribution. Methods We modified two parallel Starling resistor model to simulate transition to collateral inflow after complete main stem occlusion. We decreased Pv from the arterial pressure (Pa) to zero, and investigated how arterial and venous pressure elevation augments rCPP. Results When core pressure exceeded venous (Pcore>Pv), rCPP=Pi−Pcore. Venous pressure (Pv) decrease from Pa to Pcore caused smaller Pi to drop augmenting rCPP. Further drop of Pv to Ppen decreased rCPP in the core but augmented rCPP in penumbra. After transition to collateral circulation, lowering Pv below Ppen further decreased rCPP and collaterals themselves became pathway for steal. Venous pressure level at which rCPP in the core becomes zero we termed the “point of no reflow” (PONR). Transition from direct to collateral circulation resulted in decreased Pi, decreased rCPP, and a shift of PONR to higher venous loading values. Arterial pressure augmentation increased rCPP, but only after venous pressure exceeded PONR. Conclusion In the presence of tissue pressure gradients, transition to collateral flow predisposes to venous steal (collateral failure) which may be reversed by venous pressure augmentation. PMID:22246692

  6. Chronic Intrinsic Transient Tracheal Occlusion Elicits Diaphragmatic Muscle Fiber Remodeling in Conscious Rodents

    PubMed Central

    Smith, Barbara K.; Martin, A. Daniel; Vandenborne, Krista; Darragh, Brittany D.; Davenport, Paul W.

    2012-01-01

    Background Although the prevalence of inspiratory muscle strength training has increased in clinical medicine, its effect on diaphragm fiber remodeling is not well-understood and no relevant animal respiratory muscle strength training-rehabilitation experimental models exist. We tested the postulate that intrinsic transient tracheal occlusion (ITTO) conditioning in conscious animals would provide a novel experimental model of respiratory muscle strength training, and used significant increases in diaphragmatic fiber cross-sectional area (CSA) as the primary outcome measure. We hypothesized that ITTO would increase costal diaphragm fiber CSA and further hypothesized a greater duration and magnitude of occlusions would amplify remodeling. Methodology/Principal Findings Sprague-Dawley rats underwent surgical placement of a tracheal cuff and were randomly assigned to receive daily either 10-minute sessions of ITTO, extended-duration, 20-minute ITTO (ITTO-20), partial obstruction with 50% of cuff inflation pressure (ITTO-PAR) or observation (SHAM) over two weeks. After the interventions, fiber morphology, myosin heavy chain composition and CSA were examined in the crural and ventral, medial, and dorsal costal regions. In the medial costal diaphragm, with ITTO, type IIx/b fibers were 26% larger in the medial costal diaphragm (p<0.01) and 24% larger in the crural diaphragm (p<0.05). No significant changes in fiber composition or morphology were detected. ITTO-20 sessions also yielded significant increases in medial costal fiber cross-sectional area, but the effects were not greater than those elicited by 10-minute sessions. On the other hand, ITTO-PAR resulted in partial airway obstruction and did not generate fiber hypertrophy. Conclusions/Significance The results suggest that the magnitude of the load was more influential in altering fiber cross-sectional area than extended-duration conditioning sessions. The results also indicated that ITTO was associated with type II

  7. 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.)

  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. Behavior of soil anchors under dynamic loads

    SciTech Connect

    Picornell, M.; Olague, B.

    1997-07-01

    Helical anchors placed in a cohesionless soil in a laboratory setting were tested under static and dynamic loads. The dynamic tests were performed after subjecting the anchors to a seating load. The dynamic load had an intensity that changed in sinusoidal fashion and was superimposed to the static seating loads. Although, the anchors have a static pull-out capacity, when the dynamic loads are applied the anchor experiences additional deformations for each load cycle. The deformations per cycle are initially high but then decrease to a nearly constant rate. Eventually, the constant rate increases suddenly accelerating until failure. This failure can take place even at small fractions of the static pull-out capacity. The rate of deformation per load cycle is found to increase for larger seating loads and for larger dynamic pulsating loads. The results of this study shows that the designer can only adjust loads to decrease the deformation rate to suit the design life of the structure.

  10. Penetration of minoxidil from ethanol/propylene glycol solutions: effect of application volume and occlusion.

    PubMed

    Tata, S; Flynn, G L; Weiner, N D

    1995-06-01

    We have previously established that the relative concentrations of propylene glycol and ethanol as a binary solvent system have a significant effect on the skin penetration of 2% solutions of minoxidil at 50 microL/cm2. The present work extends these studies and investigates the penetration of minoxidil from the different vehicle combinations as functions of application volume and occlusion. Decreasing the application volume has a variable effect which depends on vehicle composition. Penetration of minoxidil from 100% ethanol solutions decreased linearly with application volume. Generally, irrespective of the volume applied, the penetration of minoxidil increased with increasing ethanol fraction with a maximum penetration at 90% ethanol. Penetration from all the formulations was enhanced upon occluding the skin, with greatest increase evident in solutions with higher volatile fraction. Penetration of minoxidil in vivo showed trends similar to those seen in vitro. PMID:7562405

  11. 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.

  12. The effectiveness of a mouth guard to protect against strong occlusion caused by modified electroconvulsive therapy.

    PubMed

    Ogami, Saori; Yamada, Morimasa; Kanazawa, Mayuko; Takeda, Kiyoshi; Kimura, Naoaki; Mizutani, Hideki; Kohase, Hikaru; Fukayama, Haruhisa

    2014-10-01

    Modified electroconvulsive therapy (m-ECT) is a treatment for mental disease such as depressive disorder. Although a muscle relaxant is used during current application, strong occlusion occurs due to the proximity of the electrode to the temporal and masseter muscles. Although a feedback mechanism to avoid excessive occlusion occurs unconsciously, the mechanism does not work under general anesthesia. Strong occlusion may cause complications such as tooth injury, pain of the jaw, lip laceration, and bleeding of the gums. Although there was a report that the insertion of shock-absorbing materials such as gauze reduces complications, there has been no study on the effectiveness of a mouth guard (MG) for alleviating the occlusal force during m-ECT. The present study investigated the effectiveness of MG for alleviation of the occlusal force and complications during m-ECT. An ethyl-vinyl-acetate (EVA) MG was used as a shock absorbing material to mitigate the strong occlusion during m-ECT to investigate the influence of MG on the occlusal force and its effectiveness. The results showed that the occlusal force was alleviated by 58 ± 22% on average using MG during m-ECT. It also helped reduce intra-oral problems such as pain and bleeding. The results suggest the effectiveness of MG for alleviating the occlusal force during m-ECT and avoiding complications due to strong occlusion. PMID:25364808

  13. 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

  14. Dynamics of load balancing with constraints

    NASA Astrophysics Data System (ADS)

    Suzuki, Hideyuki

    2014-10-01

    In this paper, we consider a centralized strategy for scheduling charging patterns of electrical vehicles and other batteries in power grids. We formulate it as a load balancing problem with constraints, which tries to distribute the charging loads both spatially and temporally. We show that a variant of herding system can be applied to load balancing.

  15. Dynamics of load balancing with constraints

    NASA Astrophysics Data System (ADS)

    Suzuki, Hideyuki

    2014-09-01

    In this paper, we consider a centralized strategy for scheduling charging patterns of electrical vehicles and other batteries in power grids. We formulate it as a load balancing problem with constraints, which tries to distribute the charging loads both spatially and temporally. We show that a variant of herding system can be applied to load balancing.

  16. A cephalometric evaluation of tongue from the rest position to centric occlusion in the subjects with class II division 1 malocclusion and class I normal occlusion

    PubMed Central

    Verma, Sanjeev K.; Tandon, Pradeep; Agrawal, D. K.; Prabhat, K. C.

    2012-01-01

    Background: One of the common types of oro-dental morphopathologic relationship is the Class II Division 1 malocclusion. Therefore, the study of tongue position in Class II Division 1 may reveal a role of the tongue in the etiology or diagnosis of malocclusion. Aims: Present study was done with the aim to evaluate the tongue position radiographically in centric occlusion and rest position in the subjects with Angle's Class 1 normal occlusion and subjects with Angle's Class II Division 1 malocclusion and to find out any differences in tongue position between Angle's Class 1 normal occlusion and Angle's Class II Division 1 malocclusion group. Materials and Methods: The present study was conducted on lateral cephalogram of 40 subjects between the age ranges of 16 to 22 years. The samples were divided into the Angle's Class 1 normal occlusion group (Group I) and the Angle's Class II Division 1 malocclusion group (Group II) with the 20 in each groups. The study involved the evaluation of tongue position at rest position and centric occlusion on the lateral head cephalogram. Results: This study for the evaluation of the tongue position from the rest position to the centric occlusion showed no statistically significant changes in both groups. However, there were greater changes in various parameters (From the rest position to the centric occlusion) in the subjects with Angle's Class II Division 1 malocclusion as compared to the subjects with the Angle's Class I normal occlusion group. Conclusion: From the present study following conclusion can be drawn: with the closure of mandible from the rest position to centric occlusion the tongue moved antero-superiorly in the tip region, superiorly in the dorsum region, and antero-superiorly in the posterior region in normal occlusion and postero-superiorly in Class II Division 1 malocclusion. PMID:24987623

  17. The effect of occlusive dressings on the energy metabolism of severely burned children.

    PubMed

    Caldwell, F T; Bowser, B H; Crabtree, J H

    1981-05-01

    Metabolic studies were performed on 23 burned children. They were studied sequentially until their burn wounds were healed. A metabolic study lasted 20 minutes, during which continuous measurements were made of O2 consumption and CO2 production rates, rectal temperature, average surface temperatures (dressings, skin and wound), body heat content, and rate of body weight loss using a bed scale. These measurements allowed solution of the heat balance equation for each study period. After 24 hours in a constant temperature room kept at 28 C and 40% relative humidity, metabolic studies were initiated when blood was drawn for catecholamine assay, followed by a metabolic analysis, after which dressings were removed and fresh silvadene applied to the wounds. No dressings were applied. Metabolic analyses were repeated after two and four hours of exposure, after which blood for catecholamine analysis was drawn and the study terminated. Without dressings in a thermally neutral environment, burn patients demonstrated an increased rate of heat loss of 27 watts/square meter body surface area (W/M2), compared with the predicted normal. The major portion of this increment is by evaporation, which increased 300%. The rate of heat production equals heat loss, and is increased 50% above the predicted normal. Occlusive dressings result in a 15 W/M2 decrease in the rate of heat loss, about evenly divided between evaporative and dry routes, with a corresponding 15 W/M2 decrease in the rate of heat production. Plasma catecholamine levels of bandaged burn patients are not significantly different from values for healed burn patients, and do not correlate with the rate of heat production. The increased heat production of burn patients is a response to an increased rate of heat loss, not vice versa. The use of occlusive dressings substantially reduces the energy requirements to manageable levels, even in patients with very large burns. PMID:7235763

  18. [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

  19. In vivo near-IR imaging of occlusal lesions at 1310 nm

    NASA Astrophysics Data System (ADS)

    Fried, Daniel; Staninec, Michal; Darling, Cynthia L.; Lee, Chulsung; Kang, Hobin; Chan, Kenneth H.

    2011-03-01

    Several in vitro studies have demonstrated the potential for transillumination imaging and optical coherence tomography operating at 1310-nm for imaging caries lesions on tooth proximal and occlusal surfaces. Recently, we demonstrated that lesions on proximal surfaces could be imaged in vivo using NIR transillumination and that PS-OCT can be used in vivo to measure early demineralization on tooth buccal and occlusal surfaces. In this paper we report the first in vivo measurements using OCT and NIR imaging of occlusal lesions that have been scheduled for restoration. Occlusal lesions were chosen that were scheduled for restoration based on conventional diagnosis that consists of visual and tactile examination. Occlusal lesions were visible in the NIR. OCT looks promising for confirming the lateral spread of occlusal caries under the dentinal-enamel junction adjacent to fissures. These studies suggest that both near infrared transillumination imaging at 1310-nm and OCT provide valuable information about the severity of caries lesions.

  20. Direct estimation of nonrigid registrations with image-based self-occlusion reasoning.

    PubMed

    Gay-Bellile, Vincent; Bartoli, Adrien; Sayd, Patrick

    2010-01-01

    The registration problem for images of a deforming surface has been well studied. External occlusions are usually well handled. In 2D image-based registration, self-occlusions are more challenging. Consequently, the surface is usually assumed to be only slightly self-occluding. This paper is about image-based nonrigid registration with self-occlusion reasoning. A specific framework explicitly modeling self-occlusions is proposed. It is combined with an intensity-based, "direct" data term for registration. Self-occlusions are detected as shrinkage areas in the 2D warp. Experimental results on several challenging data sets show that our approach successfully registers images with self-occlusions while effectively detecting the self-occluded regions. PMID:19926901

  1. 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.

  2. 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.

  3. Material fatigue data obtained by card-programmed hydraulic loading system

    NASA Technical Reports Server (NTRS)

    Davis, W. T.

    1967-01-01

    Fatigue tests using load distributions from actual loading histories encountered in flight are programmed on punched electronic accounting machine cards. With this hydraulic loading system, airframe designers can apply up to 55 load levels to a test specimen.

  4. 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...

  5. 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...

  6. 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...

  7. 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...

  8. Robust lane sensing and departure warning under shadows and occlusions.

    PubMed

    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

  9. Occlusion of the HIV poly(A) site.

    PubMed

    Weichs an der Glon, C; Monks, J; Proudfoot, N J

    1991-02-01

    To investigate the selective use of poly(A) sites in the 3' long terminal repeat (LTR) but not the 5' LTR of retroviruses, we have studied the poly(A) site of the human immunodeficiency virus (HIV-1). Using hybrid HIV/alpha-globin gene constructs, we demonstrate that the HIV poly(A) site is inactive or occluded when adjacent to an active promoter, either the homologous HIV promoter or the alpha-globin gene promoter. Furthermore, this occlusion of the HIV poly(A) site occurs over a considerable distance of up to at least 500 bp. In contrast, two nonretroviral poly(A) sites [alpha-globin and a synthetic poly(A) site] are active when close to a promoter. We also show that a short fragment of approximately 60 nucleotides containing the HIV poly(A) site is fully active when placed at the 3' end of the human alpha-globin gene or within the rabbit beta-globin gene. This result rules out the requirement of more distant upstream elements for the activity of the HIV poly(A) site, as has been suggested for other viral poly(A) sites. Finally, we show that the GT-rich downstream region of the HIV poly(A) site confers poly(A) site occlusion properties on a synthetic poly(A) site. This result focuses attention on this more variable part of a poly(A) site in retroviruses as a possible general signal for poly(A) site occlusion. PMID:1995416

  10. Coronary artery occlusion extends perfusion territory boundaries through microvascular collaterals.

    PubMed

    Cicutti, N; Rakusan, K; Downey, H F

    1994-01-01

    Simultaneous in vivo infusions of two different colored 10 microns microsphere suspensions into the left anterior descending (LAD; red spheres) and left circumflex (LCx; blue spheres) coronary arteries of nine anesthetized dogs identified a specific region of canine myocardium perfused by both arterial branches. Subsequently, the LAD was ligated and a third (green) set of micropheres was infused into the patent LCx artery. Analysis of 40 microns serial sections of tissue revealed interface zones with capillaries perfused by both arteries. The first zone, defined as the Interface Transistion Zone (ITZ) was formed by an intermingling of microvessels supplied by the parent arteries of the adjacent perfusion territories; it separated tissue containing only one or the other colored microspheres. Another zone, defined as the Boundary Watershed Zone was located within the ITZ and had capillaries containing both red and blue microspheres. The width of ITZ was 53377 +/- 817 microns (mean +/- SD), and the width of the BWZ was 3358 +/- 618 microns. Green microspheres, infused into the LCx following coronary occlusion were also found in the ITZ and BWZ. Furthermore, capillaries perfused exclusively by the LAD before occlusion (tissue with red but not blue microspheres) adjacent to the perfusion interface contained green microspheres as well as red/green aggregates, indicating lateral extension of the LCx perfusion territory. This extension of the LCx territory was quantitated by comparing the location at which densities of green microspheres or green/red aggregates decreased abruptly compared to the location of the original ITZ and BWZ boundaries, respectively. Results showed that LAD occlusion caused a 24% expansion of the ITZ and a 48% expansion of the BWZ. In addition, all expansions were significantly greater in subepicardial compared to subendocardial regions (p < 0.001). These results clearly demonstrate the capability of microvascular anastomoses in providing blood flow

  11. 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

  12. 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

  13. Extrapolation of vertical target motion through a brief visual occlusion.

    PubMed

    Zago, Myrka; Iosa, Marco; Maffei, Vincenzo; Lacquaniti, Francesco

    2010-03-01

    It is known that arbitrary target accelerations along the horizontal generally are extrapolated much less accurately than target speed through a visual occlusion. The extent to which vertical accelerations can be extrapolated through an occlusion is much less understood. Here, we presented a virtual target rapidly descending on a blank screen with different motion laws. The target accelerated under gravity (1g), decelerated under reversed gravity (-1g), or moved at constant speed (0g). Probability of each type of acceleration differed across experiments: one acceleration at a time, or two to three different accelerations randomly intermingled could be presented. After a given viewing period, the target disappeared for a brief, variable period until arrival (occluded trials) or it remained visible throughout (visible trials). Subjects were asked to press a button when the target arrived at destination. We found that, in visible trials, the average performance with 1g targets could be better or worse than that with 0g targets depending on the acceleration probability, and both were always superior to the performance with -1g targets. By contrast, the average performance with 1g targets was always superior to that with 0g and -1g targets in occluded trials. Moreover, the response times of 1g trials tended to approach the ideal value with practice in occluded protocols. To gain insight into the mechanisms of extrapolation, we modeled the response timing based on different types of threshold models. We found that occlusion was accompanied by an adaptation of model parameters (threshold time and central processing time) in a direction that suggests a strategy oriented to the interception of 1g targets at the expense of the interception of the other types of tested targets. We argue that the prediction of occluded vertical motion may incorporate an expectation of gravity effects. PMID:19882150

  14. [Prevalence of normal occlusion traits in deciduous dentition].

    PubMed

    Ferreira, R I; Barreira, A K; Soares, C D; Alves, A C

    2001-01-01

    The aim of this research was to study the normal occlusal patterns of deciduous dentition in Brazilian preschool children. The sample consisted of 356 preschool children, of both genders, aged 3-5 1/2 years from the urban zone of Salvador, Bahia. The occlusion exam was carried out by two examiners, in the classroom, utilizing a wooden spatula. The data were analyzed by the statistical program EPI-INFO 6.02 using the Chi-squared test. The frequency of the type I arch was 43.3% for the upper and 46.3% for the lower arch. The frequency of the type II arch was 56.7% for the upper and 53.75 for the lower arch, however, no difference between genders was noticed. The distribution of primate spaces was: 89.9% for the upper and 67.1% for the lower arch. This prevalence decreased significantly as age increased (p < 0.01). Normal canine relationship was found in almost 60% of the children for the right and left sides. Out of 712 evaluated terminal planes, 55.9% presented mesial terminal step for the primary second molars, 37.9% straight terminal plane and 6.2% distal step. The results permitted to conclude that the presence of generalized spacing between incisors, commonly described by other authors, was not the most prevailing condition for both arches in this sample. On the other hand, primate spaces were the most common ones. The most frequent normal occlusal patterns for canine and molar relationships were found to be the Class I patterns. PMID:11705312

  15. 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

  16. 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.

  17. 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

  18. Biomechanical behavior of restored and unrestored mandible with shortened dental arch under vertical loading condition.

    PubMed

    Tanasić, Ivan; Tihaček-Šojić, Ljiljana; Milić-Lemić, Aleksandra

    2012-01-01

    The aim of this in vitro study was to investigate the strain distribution of the compressed mandible bone under the applied restoration- removable partial denture and to compare with the same but unrestored mandible under vertical (occlusal) load and to find out whether removable partial denture-restored or unrestored mandible causes greater strain effect on supporting tissue. Four mandible models were tested during loading for the purpose of strain measuring. Digital image correlation system (GOM - German Optical Measuring, Braunschweig, Germany), used for measuring strain consists of two digital cameras and software ARAMIS (6.2.0, Braunschweig, Germany). Remaining teeth suffer from greater strain in the mandible model without removable partial denture (7.5-10%). On the contrary, mandible with removable partial denture shows the maximum strain below the denture saddle (3.5%). However, it can be noticed that the marginal bone of the second lower praemolar in both experimental models is deformed whether the mandible model has (2.8%) or has not (10%) replacement. Within the limitations of this study the higher strain is observed in mandible model without replacement and the strain is limited locally, in the bone region that surrounds remaining teeth and mental foramen. PMID:23394230

  19. 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.

  20. [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. PMID:279445

  1. Dermatomyositis-Related Nonischemic Central Retinal Vein Occlusion.

    PubMed

    Wang, Yvonne; Morgan, Michael L; Espino Barros Palau, Angelina; Lee, Andrew G; Foroozan, Rod

    2015-09-01

    A 25-year-old woman with dermatomyositis suffered a right central retinal vein occlusion (CRVO) with visual acuity of 20/40. Examination of the right eye showed vitreous cells, suggesting inflammation of the central retinal vein leading to a CRVO as the presumed mechanism. She was admitted to hospital, and extensive evaluation was negative. She was maintained on corticosteroids to manage her dermatomyositis. One month later, she had macular edema and elevated intraocular pressure. Both resolved with dorzolamide, timolol, and intravitreal bevacizumab, and vision returned to 20/20 in the right eye. PMID:25815857

  2. Pulmonary Capillary Hemangiomatosis and Pulmonary Veno-occlusive Disease.

    PubMed

    Chaisson, Neal F; Dodson, Mark W; Elliott, Charles Gregory

    2016-09-01

    This article provides an overview of pulmonary veno-occlusive disease (PVOD) and pulmonary capillary hemangiomatosis (PCH), two disorders that challenge clinicians, radiologists, and pathologists because they often mimic pulmonary arterial hypertension (PAH). The article reviews the features that differentiate PVOD and PCH from PAH. The article also describes the overlap of PVOD and PCH, highlighted by recent reports of families diagnosed with PVOD or PCH caused by EIF2AK4 mutations. In addition, the article outlines current approaches to the diagnosis and treatment of PVOD and PCH. PMID:27514598

  3. Image-Guided Thromboembolectomy of Acute Arterial Occlusion in Children.

    PubMed

    Kim, Song-Yi; Han, Ahram; Choi, Chanjoong; Min, Sang-Il; Kim, Hyo-Cheol; Ha, Jongwon; Min, Seung-Kee

    2016-07-01

    Acute arterial thromboembolism (ATE) is rare in childhood, but this medical emergency requires immediate treatment. Described herein are separate instances of lower extremity ATE in 2 children, both of whom were successfully managed through image-guided thromboembolectomy (IGT). One patient, a 34-month-old female child with nephrotic syndrome, developed bilateral iliac and popliteal thromboembolic arterial occlusions after high-dose steroid therapy. Another 9-year-old girl suffered an embolism of left popliteal artery due to infectious endocarditis. Both patients underwent IGT using over-the-wire Fogarty catheters. During follow-up, presenting symptoms resolved without significant complications. PMID:27177711

  4. Strategies to prevent radial artery occlusion after transradial PCI.

    PubMed

    Pancholy, Samir B

    2014-07-01

    Radial artery occlusion (RAO) is the most common structural consequence of transradial access (TRA) with an estimated incidence ranging from 2-10 %. Its occurrence is free of any major clinical consequences, especially at rest, with most if not all cases of digital ischemia occurring as a result of embolization, rather than RAO. The incidence of RAO is unacceptably high if "best practices" are not followed. Strategies to prevent RAO need to be implemented to preserve radial artery patency in order to exploit other benefits of TRA. PMID:24890765

  5. Current status of percutaneous coronary intervention of chronic total occlusion

    PubMed Central

    Ge, Jun-bo

    2012-01-01

    This paper describes the current status of percutaneous coronary intervention (PCI) for totally occluded coronary arteries. Chronic total occlusion is associated with 10%–20% of all PCI procedures. Results show that opening an occluded vessel, especially one supplying a considerable area of myocardium, may be beneficial for a patient’s angina relief and heart function. We describe the devices used currently in re-canalization such as new wires, microcatheters (including Tonus and Cosair) and intravascular ultrasound guidance. Different techniques to improve the success rate and reduce complications are discussed in detail. PMID:22843178

  6. A hybrid approach to recanalization of a chronic iliofemoral occlusion.

    PubMed

    Ahanchi, Sadaf Sadie; Panneton, Jean Michel; Stout, Christopher Lee

    2013-01-01

    The Viabahn covered stent (W. L. Gore and Associates Inc, Flagstaff, Ariz) is made of expanded polytetrafluoroethylene attached to an external nitinol stent and is primarily used in the endovascular treatment of lower extremity arterial occlusive disease. The use of this device as an open conduit for lower extremity revascularization has been rarely reported. We expand on this experience by presenting a case of hybrid endovascular and open iliofemoral bypass in which we used the Viabahn endoprosthesis to recanalize an occluded iliac artery, followed by direct suturing of the distal portion of the Viabahn stent graft to the native common femoral artery bifurcation. PMID:22963813

  7. 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

  8. Left main coronary artery occlusion after percutaneous aortic valve implantation.

    PubMed

    Bartorelli, Antonio L; Andreini, Daniele; Sisillo, Erminio; Tamborini, Gloria; Fusari, Melissa; Biglioli, Paolo

    2010-03-01

    Left main coronary artery occlusion occurred immediately after transfemoral aortic valve implantation in an 87-year-old woman, which resulted in ventricular fibrillation and hemodynamic collapse. This life-threatening complication was promptly diagnosed with transesophageal echocardiography, which showed the disappearance of diastolic left main coronary artery jet flow and was confirmed with aortic root angiography. After prompt defibrillation, hemodynamic support was obtained with intra-aortic balloon pump and inotropic drugs. Functional recovery and survival were achieved with coronary stenting. This report highlights the importance of an integrated team approach of highly skilled specialists for these novel interventions. PMID:20172163

  9. Real-Time Color-Doppler Guidance of HIFU for the Selective Avoidance or Occlusion of Blood Vessels

    NASA Astrophysics Data System (ADS)

    Rabkin, Brian A.; Zderic, Vesna; Vaezy, Shahram

    2005-03-01

    High-intensity focused ultrasound (HIFU) has been shown to effectively occlude blood vessels deep within tissue. The objective of the current study was to synchronize HIFU and color-Doppler ultrasound (US) for the real-time visualization of flow within blood vessels during HIFU treatment. The excitation of the HIFU was synchronized with the color-Doppler imager by collecting the excitation pulses of one of the elements of either a curved array intracavitary (C 9-5) or an intraoperative (CL 10-5) imaging probe. The collected excitation pulse was converted into a TTL-high pulse, which was delayed and gated to time the excitation duration and location of the HIFU pulse with respect to each imaging frame. The single pulse was used to drive a 3.2 MHz concave HIFU transducer (focal length of 3.5 cm, f-number 1) while the US imager was not collecting RF signals from the treatment region of the US image. The feasibility of the system was demonstrated in vivo by the selective ablation of tissue adjacent to, or the occlusion of, large vessels (including the femoral artery) both transcutaneously and interoperatively in the rabbit and pig. For the occlusion of vessels, the HIFU focus was placed immediately distal (with respect to the transducer) to the vessel at a depth of 2-2.5 cm. HIFU was applied at in situ intensities of 1000-2000 W/cm2, at a duty cycle of 50-75%, and a HIFU pulse repetition frequency (set by the US image frame rate) of 6-18 Hz. During each HIFU exposure, the HIFU pulse resulted in color interference bands running vertically within the color-Doppler window. Through the synchronization of the US imager with the HIFU excitation, the location and duration of the interference bands were set outside the treatment region within each image frame. This provided the operator with a clear view of the HIFU treatment site during therapy. Gross assessment showed necrosis of the tissue surrounding the HIFU treated vessel and occlusion of vessels up to 4 mm in diameter

  10. Shape Tracking with Occlusions via Coarse-to-Fine Region-Based Sobolev Descent.

    PubMed

    Yang, Yanchao; Sundaramoorthi, Ganesh

    2015-05-01

    We present a method to track the shape of an object from video. The method uses a joint shape and appearance model of the object, which is propagated to match shape and radiance in subsequent frames, determining object shape. Self-occlusions and dis-occlusions of the object from camera and object motion pose difficulties to joint shape and appearance models in tracking. They are unable to adapt to new shape and appearance information, leading to inaccurate shape detection. In this work, we model self-occlusions and dis-occlusions in a joint shape and appearance tracking framework. Self-occlusions and the warp to propagate the model are coupled, thus we formulate a joint optimization problem. We derive a coarse-to-fine optimization method, advantageous in tracking, that initially perturbs the model by coarse perturbations before transitioning to finer-scale perturbations seamlessly. This coarse-to-fine behavior is automatically induced by gradient descent on a novel infinite-dimensional Riemannian manifold that we introduce. The manifold consists of planar parameterized regions, and the metric that we introduce is a novel Sobolev metric. Experiments on video exhibiting occlusions/dis-occlusions, complex radiance and background show that occlusion/dis-occlusion modeling leads to superior shape accuracy. PMID:26353328

  11. Selectively active markers for solving of the partial occlusion problem in matchmoving and chromakeying workflow

    NASA Astrophysics Data System (ADS)

    Mazurek, Przemysław

    2013-09-01

    Matchmoving (Match Moving) is the process used for the estimation of camera movements for further integration of acquired video image with computer graphics. The estimation of movements is possible using pattern recognition, 2D and 3D tracking algorithms. The main problem for the workflow is the partial occlusion of markers by the actor, because manual rotoscoping is necessary for fixing of the chroma-keyed footage. In the paper, the partial occlusion problem is solved using the invented, selectively active electronic markers. The sensor network with multiple infrared links detects occlusion state (no-occlusion, partial, full) and switch LED's based markers.

  12. Does Abutment Collar Length Affect Abutment Screw Loosening After Cyclic Loading?

    PubMed

    Siadat, Hakimeh; Pirmoazen, Salma; Beyabanaki, Elaheh; Alikhasi, Marzieh

    2015-07-01

    A significant vertical space that is corrected with vertical ridge augmentation may necessitate selection of longer abutments, which would lead to an increased vertical cantilever. This study investigated the influence of different abutment collar heights on single-unit dental implant screw-loosening after cyclic loading. Fifteen implant-abutment assemblies each consisted of an internal hexagonal implant were randomly assigned to 3 groups: Group1, consisting of 5 abutments with 1.5 mm gingival height (GH); Group2, 5 abutments with 3.5 mm GH; and Group3, 5 abutments with 5.5 mm GH. Each specimen was mounted in transparent auto-polymerizing acrylic resin block, and the abutment screw was tightened to 35 Ncm with an electric torque wrench. After 5 minutes, initial torque loss (ITL) was recorded for all specimens. Metal crowns were fabricated with 45° occlusal surface and were placed on the abutments. A cyclic load of 75 N and frequency of 1 Hz were applied perpendicular to the long axis of each specimen. After 500 000 cycles, secondary torque loss (STL) was recorded. One-way ANOVA analysis was used to evaluate the effects of abutment collar height before and after cyclic loading. One-way ANOVA showed that ITL among the groups was not significantly different (P = .52), while STL was significantly different among the groups (P = .008). Post-hoc Tukey HSD tests showed that STL values were significantly different between the abutments with 1.5 mm GH (Group1) and with 5.5 mm GH (Group3) (P = .007). A paired comparison t-test showed that cyclic loading significantly influenced the STL in comparison with the ITL in each group. Within the limitations of this study, it can be concluded that increase in height of the abutment collar could adversely affect the torque loss of the abutment screw. PMID:26237093

  13. 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.

  14. Red bone marrow doses, integral absorbed doses, and somatically effective dose equivalent from four maxillary occlusal projections

    SciTech Connect

    Berge, T.I.; Wohni, T.

    1984-02-01

    Phantom measurements of red bone marrow (RBM) doses, integral absorbed doses, and somatically effective dose equivalent (SEDE) from four different maxillary occlusal projections are presented. For each projection, different combinations of focus-skin distances and tube potentials were compared with regard to the patient's radiation load. The axial incisal view produced the highest patient exposures, with a maximum red bone marrow dose of 122.5 microGy/exposure, integral absorbed dose of 8.6 mJ/exposure, and SEDE values of 39.6 microSv/exposure. The corresponding values from the frontal, lateral occlusal, and tuber views ranged between 4% and 44% of the axial incisal view values for the integral absorbed dose and SEDE values, and between 0.3% and 3% for the red bone marrow doses. Increasing the focus-skin distance from 17.5 cm to 27 cm is accompanied by a 24% to 30% reduction in integral absorbed dose. Increasing the tube potential from 50 kV to 65 kV likewise results in a 23% reduction in absorbed energy.

  15. A Correlation of Permanent Anterior Tooth Fracture with Type of Occlusion and Craniofacial Morphology

    PubMed Central

    Kumar, Ashish; Rana, Vivek; Aggarwal, Abhai; Chandra, Lokesh

    2013-01-01

    ABSTRACT Aims: To assess the relationship of anterior tooth fractures with type of occlusion and craniofacial morphology. Materials and methods: The study was conducted on 76 subjects of age group 9 to 13 years with at least one fractured permanent anterior teeth. Lateral cephalograms were taken and study models were prepared for each subject with prior consent of their parents. Then cephalometric tracings were done and overjet was recorded through study models. Statistical analysis used: Standard error of mean (SEM) and unpaired t-test has been applied to test the significant difference between the seven parameters under consideration. Karl Pearson correlation test has also been used to correlate all the parameters used in this study with each other. All the tests were performed at 5 and 1% levels of significance. Results: Frequency of tooth fracture increases with increasing overjet. At 5% level of significance, significant difference were observed between the standard values and observed values for overjet measurement, SNA angle, SNB angle, ANB angle, upper incisor to NA (angle), upper incisor to NA (linear) and interincisal angle for overall data and also for both male and female data separately. Conclusion: Probability of permanent anterior tooth fracture increases with increasing overjet. A significant difference was observed between the standard value and the observed values of all parameters under consideration. How to cite this article: Chaturvedi R, Kumar A, Rana V, Aggarwal A, Chandra L. A Correlation of Permanent Anterior Tooth Fracture with Type of Occlusion and Craniofacial Morphology. Int J Clin Pediatr Dent 2013;6(2):80-84. PMID:25206197

  16. Chronic total occlusion angioplasty in the United States.

    PubMed

    Grantham, J Aaron; Marso, Steven P; Spertus, John; House, John; Holmes, David R; Rutherford, Barry D

    2009-06-01

    Coronary chronic total occlusions (CTOs) are commonly encountered complex lesions identified in 15% of all patients referred for coronary angiography. Chronic total occlusion remains the most powerful predictor of referral for coronary bypass surgery. The benefits of CTO percutaneous coronary intervention (PCI) include symptom relief, improved left ventricular function, and potentially a survival advantage associated with success when compared with failed CTO-PCI. Data from the NCDR (National Cardiovascular Data Registry) suggest that CTO-PCI attempt rates in the U.S. have not changed over the past 5 years despite significant advances in techniques and technology, some of which we review here. Additionally, these data highlight a major disparity in attempt rates based on operator PCI volume. Remaining barriers to attempting CTO-PCI in the U.S. include operator inexperience, the perception of increased risk of CTO-PCI, and financial disincentives to operators and hospitals. To overcome operator inexperience, participation in CTO clubs, the invitation of guest operators, and a dedicated CTO day can be implemented at institutions committed to learning advanced CTO-PCI techniques so that operators can overcome the barriers and offer patients access to percutaneous therapy when it is clinically indicated. PMID:19539249

  17. Mouse Transient Global Ischemia Two-Vessel Occlusion Model

    PubMed Central

    Pontarelli, Fabrizio; Ofengeim, Dimitry; Zukin, R. Suzanne; Jonas, Elizabeth A.

    2016-01-01

    Transient global ischemia in rodents induces delayed death of hippocampal CA1 neurons, as well as in some hilar neurons of the dentate gyrus, medium aspiny neurons of the striatum, pyramidal neurons in neocortical layers II, V and VI, and Purkinje neurons of the cerebellum. In contrast to focal ischemia that mimics regional stroke in humans, this model of global ischemia mimics the brain injury that occurs after human cardiac arrest. Early events include caspase activation, cleavage of anti-death Bcl-2 family proteins and large mitochondrial channel activity. Genetically engineered mice provide opportunities for study such as the knock-in mouse expressing a caspase-resistant form of Bcl-xL found to exhibit markedly reduced mitochondrial channel activity and reduced vulnerability to ischemia-induced neuronal death1. It is therefore relevant to adapt and develop a simple protocol for producing transient global ischemia in mouse2. The two-vessel occlusion model has been specifically developed to provide optimal outcomes in mouse and offers several advantages over the four-vessel occlusion model traditionally used in rat including the relative ease of the procedure as well as only a single day of surgery. However it should be noted that this procedure has a higher morbidity rate compared to other ischemia models as well as a higher degree of variability. These two disadvantages necessitate the use of a larger cohort of animals, which for many healthy breeding transgenic animals is a non-deterring factor.

  18. 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. PMID:23395151

  19. A case of veno-occlusive disease following liver transplantation

    PubMed Central

    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. PMID:24348779

  20. 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

  1. Prevalence of Orthodontic Treatment Need and Occlusal Traits in Schoolchildren

    PubMed Central

    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.

  2. Endoscopic bronchial occlusion with silicone spigots under virtual bronchoscopic navigation

    PubMed Central

    Sato, Shingo; Shiroyama, Takayuki; Nishida, Takuji; Nishihara, Takashi; Okamoto, Norio

    2016-01-01

    Abstract A 68‐year‐old woman with interstitial lung disease related to dermatomyositis and systemic scleroderma was admitted to our hospital with fever and dyspnoea. Although the fever was reduced after antibiotic therapy, a left pneumothorax suddenly occurred on day 27 after admission. A continuous air leak persisted despite chest drainage with three tubes and repeated pleurodesis. Chest computed tomography (CT) images showed a cavitary lesion with a pinhole in the left upper division, which was suspected to be the affected lesion with the air leak. Virtual bronchoscopic navigation images were constructed from CT data. Bronchial occlusion with Endobronchial Watanabe Spigots (EWSs) was performed on day 52. Two medium‐sized EWSs were inserted into the left B1 + 2a and B1 + 2b, and the air leak stopped immediately. No procedure‐related adverse events occurred. All three chest tubes were successfully removed by day 60. This case demonstrates that virtual bronchoscopic navigation can improve bronchial occlusion procedures using EWSs. PMID:27512560

  3. Item type, occlusion, and gender differences in mental rotation.

    PubMed

    Doyle, Randi A; Voyer, Daniel; Lesmana, Maryani

    2016-08-01

    Two experiments were conducted to examine the role of item type in mental rotation. In each experiment, participants completed two computerized mental rotation tasks, one with blocks as stimuli and one with human figures as stimuli. The tasks were formatted either as a multiple-choice psychometric test (Experiment 1) or as a same-different type task (Experiment 2). Aside from the expected replication of a decreased effect of occlusion on women's accuracy when processing human figures compared to block figures, it was hypothesized that response times would increase when processing the complex but familiar human figures, compared to the simple but unfamiliar block figures. In Experiment 1, the results relevant to occlusion were replicated. However, the presence of a speed-accuracy trade-off suggested that participants processed human figures faster but less accurately than block figures. In Experiment 2, both men and women performed faster and more accurately when processing occluded human figures than when processing nonoccluded human figures. The effect of item type, its potential link to embodied cognition, and the role of strategy selection on gender differences in mental rotation are discussed. PMID:26325234

  4. Applied Nanotoxicology.

    PubMed

    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

  5. 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. PMID:24447195

  6. Functional Development of the Coronary Collateral Circulation During Coronary Artery Occlusion in the Conscious Dog

    PubMed Central

    Bloor, Colin M.; White, Francis C.

    1972-01-01

    We studied changes in the coronary collateral circulation during coronary artery occlusion in 14 conscious dogs by: a) determining simultaneous changes in peripheral coronary pressure (PCP) and retrograde flow (RF) after abrupt coronary artery occlusion; b) correlating these functional indices with quantitative anatomic indices (AI) of coronary collateral development (Menick et al: Am Heart J 82:503-510, 1971); and c) observing changes in these indices after repeated reocclusions of a coronary artery. These dogs were subjected to left circumflex coronary artery (LCCA) occlusions for 2 hours to 8 days; pressure tubes were implanted in the aorta and LCCA, the latter tube placed distal to an occlusive cuff for PCP and RF measurements. Afterwards the animals were sacrificed, their hearts injected with a modified Schlesinger's gelatin mass, and AI determined. During 2 to 24 hour LCCA occlusions (11 dogs) mean PCP rose to levels 50 to 80% of prevailing aortic pressure. During repreated 2- to 24-hour occlusions (2 dogs) in the same dog, the rate at which PCP rose increased. Retrograde flow was unchanged during 2- to 24-hour occlusions. Anatomic indices of these dogs were in the same range as those observed in unoccluded controls. When LCCA occlusion was maintained for more than 4 days (3 dogs), mean PCP rose during the first 24 hours and then remained stable; RF did not change until 4 days into occlusion and then increased. Anatomic indices of dogs occluded for more than 4 days were significantly greater (P < 0.001) than those of the 2- to 24-hour occlusion groups. Our study shows that: a) the early PCP rise after occlusion is not associated with an increase in RF, b) RF is a better index of collateral function and c) RF correlated well with the anatomic development of the collateral bed. ImagesFig 2Fig 1 PMID:5033259

  7. Direct Pressure Monitoring Accurately Predicts Pulmonary Vein Occlusion During Cryoballoon Ablation

    PubMed Central

    Kosmidou, Ioanna; Wooden, Shannnon; Jones, Brian; Deering, Thomas; Wickliffe, Andrew; Dan, Dan

    2013-01-01

    Cryoballoon ablation (CBA) is an established therapy for atrial fibrillation (AF). Pulmonary vein (PV) occlusion is essential for achieving antral contact and PV isolation and is typically assessed by contrast injection. We present a novel method of direct pressure monitoring for assessment of PV occlusion. Transcatheter pressure is monitored during balloon advancement to the PV antrum. Pressure is recorded via a single pressure transducer connected to the inner lumen of the cryoballoon. Pressure curve characteristics are used to assess occlusion in conjunction with fluoroscopic or intracardiac echocardiography (ICE) guidance. PV occlusion is confirmed when loss of typical left atrial (LA) pressure waveform is observed with recordings of PA pressure characteristics (no A wave and rapid V wave upstroke). Complete pulmonary vein occlusion as assessed with this technique has been confirmed with concurrent contrast utilization during the initial testing of the technique and has been shown to be highly accurate and readily reproducible. We evaluated the efficacy of this novel technique in 35 patients. A total of 128 veins were assessed for occlusion with the cryoballoon utilizing the pressure monitoring technique; occlusive pressure was demonstrated in 113 veins with resultant successful pulmonary vein isolation in 111 veins (98.2%). Occlusion was confirmed with subsequent contrast injection during the initial ten procedures, after which contrast utilization was rapidly reduced or eliminated given the highly accurate identification of occlusive pressure waveform with limited initial training. Verification of PV occlusive pressure during CBA is a novel approach to assessing effective PV occlusion and it accurately predicts electrical isolation. Utilization of this method results in significant decrease in fluoroscopy time and volume of contrast. PMID:23485956

  8. Direct pressure monitoring accurately predicts pulmonary vein occlusion during cryoballoon ablation.

    PubMed

    Kosmidou, Ioanna; Wooden, Shannnon; Jones, Brian; Deering, Thomas; Wickliffe, Andrew; Dan, Dan

    2013-01-01

    Cryoballoon ablation (CBA) is an established therapy for atrial fibrillation (AF). Pulmonary vein (PV) occlusion is essential for achieving antral contact and PV isolation and is typically assessed by contrast injection. We present a novel method of direct pressure monitoring for assessment of PV occlusion. Transcatheter pressure is monitored during balloon advancement to the PV antrum. Pressure is recorded via a single pressure transducer connected to the inner lumen of the cryoballoon. Pressure curve characteristics are used to assess occlusion in conjunction with fluoroscopic or intracardiac echocardiography (ICE) guidance. PV occlusion is confirmed when loss of typical left atrial (LA) pressure waveform is observed with recordings of PA pressure characteristics (no A wave and rapid V wave upstroke). Complete pulmonary vein occlusion as assessed with this technique has been confirmed with concurrent contrast utilization during the initial testing of the technique and has been shown to be highly accurate and readily reproducible. We evaluated the efficacy of this novel technique in 35 patients. A total of 128 veins were assessed for occlusion with the cryoballoon utilizing the pressure monitoring technique; occlusive pressure was demonstrated in 113 veins with resultant successful pulmonary vein isolation in 111 veins (98.2%). Occlusion was confirmed with subsequent contrast injection during the initial ten procedures, after which contrast utilization was rapidly reduced or eliminated given the highly accurate identification of occlusive pressure waveform with limited initial training. Verification of PV occlusive pressure during CBA is a novel approach to assessing effective PV occlusion and it accurately predicts electrical isolation. Utilization of this method results in significant decrease in fluoroscopy time and volume of contrast. PMID:23485956

  9. Effect of loading on the development of nerve fibers around oral implants in the dog mandible.

    PubMed

    Wada, S; Kojo, T; Wang, Y H; Ando, H; Nakanishi, E; Zhang, M; Fukuyama, H; Uchida, Y

    2001-06-01

    Occlusal forces cause stress which morphologically affects the supporting tissues of implants. The aim of this study was to examine the effects of occlusal forces on the distribution of neurofilament protein (NFP)-positive nerve fibers in the tissue of peri-implant bone. The bilateral 2nd, 3rd and 4th mandibular premolars and the 1st molars were extracted from three mongrel dogs. After 4 months of healing, 4 screw-type implants were inserted in the oral cavity. Three months after insertion, the implants on the molar site were loaded by occlusal forces, while those on the premolar site were unloaded. After a further 3 months, the dogs were sacrificed, and specimens were prepared for immunohistochemical NFP-positive staining by the labeled-streptavidin-biotin method. Many NFP-positive nerve fibers were found in the tissues of the loaded site when compared with the unloaded site. These fibers were localized in both the bone marrow space and in the peri-implant fibrous tissue. They had two types of nerve endings: simple free nerve endings, and nerve endings with tree-like ramifications. The present results suggest that loading by occlusal force causes an increase in the number of NFP-positive nerve fibers, many of which have free nerve endings in the peri-implant tissue. The possible role of these NFP-positive nerve fibers is discussed. PMID:11359478

  10. 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.

  11. 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.

  12. Applied Koopmanisma)

    NASA Astrophysics Data System (ADS)

    Budišić, Marko; Mohr, Ryan; Mezić, Igor

    2012-12-01

    A majority of methods from dynamical system analysis, especially those in applied settings, rely on Poincaré's geometric picture that focuses on "dynamics of states." While this picture has fueled our field for a century, it has shown difficulties in handling high-dimensional, ill-described, and uncertain systems, which are more and more common in engineered systems design and analysis of "big data" measurements. This overview article presents an alternative framework for dynamical systems, based on the "dynamics of observables" picture. The central object is the Koopman operator: an infinite-dimensional, linear operator that is nonetheless capable of capturing the full nonlinear dynamics. The first goal of this paper is to make it clear how methods that appeared in different papers and contexts all relate to each other through spectral properties of the Koopman operator. The second goal is to present these methods in a concise manner in an effort to make the framework accessible to researchers who would like to apply them, but also, expand and improve them. Finally, we aim to provide a road map through the literature where each of the topics was described in detail. We describe three main concepts: Koopman mode analysis, Koopman eigenquotients, and continuous indicators of ergodicity. For each concept, we provide a summary of theoretical concepts required to define and study them, numerical methods that have been developed for their analysis, and, when possible, applications that made use of them. The Koopman framework is showing potential for crossing over from academic and theoretical use to industrial practice. Therefore, the paper highlights its strengths in applied and numerical contexts. Additionally, we point out areas where an additional research push is needed before the approach is adopted as an off-the-shelf framework for analysis and design.

  13. Applied Koopmanism.

    PubMed

    Budisić, Marko; Mohr, Ryan; Mezić, Igor

    2012-12-01

    A majority of methods from dynamical system analysis, especially those in applied settings, rely on Poincaré's geometric picture that focuses on "dynamics of states." While this picture has fueled our field for a century, it has shown difficulties in handling high-dimensional, ill-described, and uncertain systems, which are more and more common in engineered systems design and analysis of "big data" measurements. This overview article presents an alternative framework for dynamical systems, based on the "dynamics of observables" picture. The central object is the Koopman operator: an infinite-dimensional, linear operator that is nonetheless capable of capturing the full nonlinear dynamics. The first goal of this paper is to make it clear how methods that appeared in different papers and contexts all relate to each other through spectral properties of the Koopman operator. The second goal is to present these methods in a concise manner in an effort to make the framework accessible to researchers who would like to apply them, but also, expand and improve them. Finally, we aim to provide a road map through the literature where each of the topics was described in detail. We describe three main concepts: Koopman mode analysis, Koopman eigenquotients, and continuous indicators of ergodicity. For each concept, we provide a summary of theoretical concepts required to define and study them, numerical methods that have been developed for their analysis, and, when possible, applications that made use of them. The Koopman framework is showing potential for crossing over from academic and theoretical use to industrial practice. Therefore, the paper highlights its strengths in applied and numerical contexts. Additionally, we point out areas where an additional research push is needed before the approach is adopted as an off-the-shelf framework for analysis and design. PMID:23278096

  14. Hyperbaric oxygen for the treatment of the rare combination of central retinal vein occlusion and cilioretinal artery occlusion.

    PubMed

    Celebi, Ali Riza Cenk; Kilavuzoglu, Ayse Ebru; Altiparmak, Ugur Emrah; Cosar, C Banu; Ozkiris, Abdullah

    2016-03-01

    A 43-year-old male presented with sudden onset of painless, blurred vision in his left eye. Dilated fundoscopic examination showed signs consistent with the diagnosis of a combination of central retinal vein occlusion (CRVO) and cilioretinal artery occlusion (CLRAO). He received daily 2-h sessions of hyperbaric oxygen treatment (HBOT), 253 kPa for 14 days. At the end of the HBOT course, the patient's left visual acuity had improved from 20/200 to 20/20. Dilated fundoscopic examination showed that the intra-retinal haemorrhages in the entire retina and the retinal whitening along the course of the CLRA seen at presentation had completely resolved. The combination of CLRAO and CRVO comprises a discrete clinical entity. Even though there are many hypotheses concerning this condition, it is most likely the result of elevated intraluminal pressure in the retinal capillaries due to CRVO that exceeds the pressure in the CLRA. HBOT may be an effective treatment for CRVO-associated CLRAO. PMID:27044464

  15. Relationship between retinal vascular occlusions and incident cerebrovascular diseases: A systematic review and meta-analysis.

    PubMed

    Zhou, Yue; Zhu, Wengen; Wang, Changyun

    2016-06-01

    Several studies investigating the role of retinal vascular occlusions, on cerebrovascular diseases (CVD) have been reported, but the results are still inconsistent. We therefore sought to evaluate the relationship between retinal vascular occlusions and CVD.We systematically searched the Cochrane Library, PubMed, and ScienceDirect databases through January 31, 2016 for studies evaluating the effect of retinal vascular occlusions on the risk of CVD. Data were abstracted using predefined criteria, and then pooled by RevMan 5.3 software.A total of 9 retrospective studies were included in this meta-analysis. When compared with individuals without retinal vascular occlusions, both individuals with retinal artery occlusion (RAO) (odds ratio [OR] = 2.01, 95% confidence interval [CI]: 1.21-3.34; P = 0.005) and individuals with retinal vein occlusion (RVO) (OR = 1.37, 95% CI: 1.24-1.50; P < 0.00001) had higher risks of developing CVD. Additionally, both individuals with central retinal artery occlusion (CRAO) (OR = 2.00, 95% CI: 1.12-3.56; P = 0.02) and branch retinal artery occlusion (BRAO) (OR = 1.60, 95% CI: 1.03-1.48; P = 0.04) were significantly associated with increased risk of CVD.Published literatures support both RVO and RAO are associated with increased risks of CVD. Further prospective studies are needed to confirm these findings. PMID:27368050

  16. 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…

  17. Object Individuation in Infancy: The Use of Featural Information in Reasoning about Occlusion Events.

    ERIC Educational Resources Information Center

    Wilcox, Teresa; Baillargeon, Renee

    1998-01-01

    Eight experiments involving 134 infants aged 7.5 to 11.5 months show that even the youngest give evidence that they use featural information to individuate objects in an occlusion event. When tested with an event-mapping task, even 9.5-month olds give evidence that they can use featural information to interpret an occlusion event as long as the…

  18. 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...

  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, 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...

  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. 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...

  3. Short series of upper limb acute arterial occlusions in 4 different etiologies and review of literature.

    PubMed

    Coskun, Selcuk; Soylu, Lutfi; Coskun, Pınar Koksal; Bayazıt, Murat

    2013-12-01

    Upper limb acute arterial occlusions are uncommon, and when compared with lower limb occlusions, only a few cases have been reported. Although atrial fibrillation is the most common cause, many conditions may lead to ischemia. In this article, 8 cases of upper limb arterial ischemia due to 4 different etiologies were reported (7 brachial, 1 axillary), and the literature was reviewed. PMID:24055482

  4. 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

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

    PubMed

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

    2002-01-01

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

  6. 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...

  7. 14 CFR 29.511 - Ground load: unsymmetrical loads on multiple-wheel units.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 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...

  8. 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...

  9. 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

  10. Development of implant loading device for animal study about various loading protocol: a pilot study

    PubMed Central

    Yoon, Joon-Ho; Park, Young-Bum; Cho, Yuna; Kim, Chang-Sung; Choi, Seong-Ho; Moon, Hong-Seok; Lee, Keun-Woo

    2012-01-01

    PURPOSE The aims of this pilot study were to introduce implant loading devices designed for animal study and to evaluate the validity of the load transmission ability of the loading devices. MATERIALS AND METHODS Implant loading devices were specially designed and fabricated with two implant abutments and cast metal bars, and orthodontic expansion screw. In six Beagles, all premolars were extracted and two implants were placed in each side of the mandibles. The loading device was inserted two weeks after the implant placement. According to the loading protocol, the load was applied to the implants with different time and method,simulating early, progressive, and delayed loading. The implants were clinically evaluated and the loading devices were removed and replaced to the master cast, followed by stress-strain analysis. Descriptive statistics of remained strain (µε) was evaluated after repeating three cycles of the loading device activation. Statistic analysis was performed using nonparametric, independent t-test with 5% significance level and Friedman's test was also used for verification. RESULTS The loading devices were in good action. However, four implants in three Beagles showed loss of osseointegration. In stress-strain analysis, loading devices showed similar amount of increase in the remained strain after applying 1-unit load for three times. CONCLUSION Specialized design of the implant loading device was introduced. The loading device applied similar amount of loads near the implant after each 1-unit loading. However, the direction of the loads was not parallel to the long axis of the implants as predicted before the study. PMID:23236575

  11. 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.

  12. Subclavian steal and rest pain in a case of brachiocephalic artery occlusion.

    PubMed

    Kapa, Suraj; Adams, Jonathon

    2008-01-01

    A patient with multiple vessel disease presented with symptoms of significant bilateral upper extremity pain and weakness that was more significant on the right side. On carotid duplex scanning, brachiocephalic artery occlusion with retrograde flow was noted through the right common carotid and right vertebral arteries at rest. Furthermore, 50% to 90% occlusion of the left internal carotid was noted. Filling of the right subclavian artery was noted to be through the right vertebral and right common carotid arteries. Unlike isolated subclavian steal syndrome, brachiocephalic artery occlusion induces significant hemodynamic alterations in extracranial arterial flow, which normally produces no symptoms at rest, but may produce symptoms with exercise. The occurrence of subclavian steal phenomenon in the presence of brachiocephalic occlusion is extremely rare. The present case is the first to report a patient presenting with bilateral upper extremity rest pain in the presence of brachiocephalic artery occlusive disease. PMID:22477423

  13. 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.

  14. Early Venous Occlusion Detection in a Free Flap Using Real-time Laser Doppler Imaging

    PubMed Central

    Alkhashnam, Héba; Sarfati, Benjamin; Kolb, Frédéric

    2013-01-01

    Summary: Early detection of venous occlusion in free flaps is particularly difficult to identify, and its duration is known to be directly proportional to flap mortality. Here, we report a case of deep inferior epigastric perforator based breast reconstruction in which the intraoperative use of a perfusion camera enabled identifying a venous occlusion based on microcirculatory pulsation dynamics in real time. The sensitivity of our proposed method suggests that in certain cases in which the onset of venous occlusion begins in the operating room we can detect and treat occlusion before sending the patient to recovery. Further development of this technique will allow for earlier and more objective decision making with regard to venous occlusion detection in free tissue transfer. PMID:25289200

  15. 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.

  16. 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

  17. Numerical computation of aeroelastically corrected transonic loads

    NASA Technical Reports Server (NTRS)

    Chipman, R.; Waters, C.; Mackenzie, D.

    1979-01-01

    A numerical scheme is presented for the computation of transonic aerodynamic loads on flexible wings. The method consists of iteratively applying the loads computed by a 3D transonic aerodynamics code to a structural model to obtain elastic twist, and then recomputing the loads. Because this iteration is performed concurrently with the iterations performed in computing the aerodynamics, flexible loads are obtained in roughly the same amount of computing time as required to obtain rigid loads. Applications of this method to a flexible supercritical transonic transport wing are presented and compared with model test data.

  18. 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. PMID:27612712

  19. 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.

  20. Central Sensitization and MAPKs are Involved in Occlusal Interference-Induced Facial Pain in Rats

    PubMed Central

    Cao, Ye; Li, Kai; Fu, Kai-Yuan; Xie, Qiu-Fei; Chiang, Chen-Yu; Sessle, Barry J.

    2013-01-01

    We previously developed a rat dental occlusal interference model of facial pain that was produced by bonding a crown onto the right maxillary first molar and was reflected in sustained facial hypersensitivity that was suggestive of the involvement of central sensitization mechanisms. The aim of the present study was to investigate potential central mechanisms involved in the occlusal interference-induced facial hypersensitivity. A combination of behavioral, immunohistochemical, Western blot and electrophysiological recording procedures was used in 98 male adult Sprague-Dawley rats that either received the occlusal interference or were sham-operated or naive rats. Immunohistochemically labeled astrocytes and microglia in trigeminal subnucleus caudalis (Vc) showed morphological changes indicative of astrocyte and microglial activation after the occlusal interference. Prolonged upregulation of p38 MAPK and ERK was also documented in Vc after placement of the occlusal interference, and was expressed in both neurons and glial cells at time points when rats showed peak mechanical facial hypersensitivity. The i.t. administration of the p38 MAPK inhibitor SB203580 to the medulla significantly inhibited the occlusal interference-induced hypersensitivity, and the ERK inhibitor PD98059 produced an even stronger effect. Central sensitization of functionally identified Vc nociceptive neurons following placement of the occlusal interference was also documented by extracellular electrophysiological recordings, and i.t. administration of PD98059 could reverse the neuronal central sensitization. These novel findings suggest that central mechanisms including central sensitization of trigeminal nociceptive neurons and non-neuronal processes involving MAPKs play significant roles in the production of occlusal interference-induced facial pain. Perspective Central mechanisms including trigeminal nociceptive neuronal sensitization, non-neuronal processes involving glial activation and

  1. 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. PMID:27111022

  2. Effect of prosthodontic planning on lateral occlusion scheme: a comparison between conventional and digital planning

    PubMed Central

    ABDUO, Jaafar; BENNAMOUN, Mohammed; TENNANT, Marc; McGEACHIE, John

    2015-01-01

    Recently, digital wax-up is proposed as a tool to aid prosthodontic planning. However, there are no data about the effect of prosthodontic planning on lateral occlusion scheme. Objective : This study aims to evaluate the impact of conventional and digital prosthodontic planning on lateral occlusion scheme. Material and Methods : Dental models of 10 patients were collected. All models had Angle Class I occlusion and were undergoing prosthodontic treatment that would influence the lateral occlusion scheme. Each set of models had received both conventional wax-up and digital wax-up. In relation to the lateral occlusion scheme, the following variables were evaluated: the prevalence of the different lateral occlusion scheme, number of contacting teeth and percentage of each contacting tooth. Four excursive positions on the working side were included: 0.5, 1.0, 2.0 and 3.0 mm from the maximal intercuspation position. Results : The lateral occlusion scheme of the two wax-up models was subjected to alterations following excursion. There was a tendency for the prevalence of canine-guided occlusion to increase and for the prevalence of group function occlusion to decrease with increasing excursion. The number of contacting teeth was decreasing with the increasing magnitude of excursion. For the 0.5 mm and 1.0 mm positions, the two wax-ups had significantly greater contacts than the pre-treatment models, while at the 2.0 mm and 3.0 mm positions, all the models were similar. For all models, canines were the most commonly contacting teeth, followed by the teeth adjacent to them. No difference was observed between the two wax-ups in relation to the number of contacting teeth. Conclusion : Although the prosthodontic planning had influenced the pattern of the lateral occlusion scheme and contacts, there was no difference between the conventional and digital prosthodontic planning. PMID:26018312

  3. Plasmacytic Aortitis with Occlusion of the Right Coronary Artery.

    PubMed

    Zambetti, Benjamin R; Garrett, Edward

    2016-01-01

    BACKGROUND Inflammation of the aortic wall, known as aortitis, is a rare clinical entity which is frequently asymptomatic, or identified when the patient presents with an aortic aneurysm or dissection. It is most often caused by infection or autoimmune vasculitides such as giant cell or Takayasu's arteritis. CASE REPORT The case presented is that of a 55-year-old man with symptomatic occlusion of the right coronary artery caused by a plasmacytic aortitis suggestive of IgG4 disease, which was successfully treated with coronary artery bypass grafting and an ascending aortic graft. CONCLUSIONS A review of the current literature emphasizes how poorly the etiology and natural history of plasmacytic aortitis is understood. PMID:27471062

  4. Plasmacytic Aortitis with Occlusion of the Right Coronary Artery

    PubMed Central

    Zambetti, Benjamin R.; Garrett, Edward

    2016-01-01

    Patient: Male, 55 Final Diagnosis: Plasmacytic aortitis Symptoms: Dizziness • nausea Medication: — Clinical Procedure: — Specialty: Surgery Objective: Unusual clinical course Background: Inflammation of the aortic wall, known as aortitis, is a rare clinical entity which is frequently asymptomatic, or identified when the patient presents with an aortic aneurysm or dissection. It is most often caused by infection or autoimmune vasculitides such as giant cell or Takayasu’s arteritis. Case Report: The case presented is that of a 55-year-old man with symptomatic occlusion of the right coronary artery caused by a plasmacytic aortitis suggestive of IgG4 disease, which was successfully treated with coronary artery bypass grafting and an ascending aortic graft. Conclusions: A review of the current literature emphasizes how poorly the etiology and natural history of plasmacytic aortitis is understood. PMID:27471062

  5. Pedestrian Counting with Occlusion Handling Using Stereo Thermal Cameras.

    PubMed

    Kristoffersen, Miklas S; Dueholm, Jacob V; Gade, Rikke; Moeslund, Thomas B

    2016-01-01

    The number of pedestrians walking the streets or gathered in public spaces is a valuable piece of information for shop owners, city governments, event organizers and many others. However, automatic counting that takes place day and night is challenging due to changing lighting conditions and the complexity of scenes with many people occluding one another. To address these challenges, this paper introduces the use of a stereo thermal camera setup for pedestrian counting. We investigate the reconstruction of 3D points in a pedestrian street with two thermal cameras and propose an algorithm for pedestrian counting based on clustering and tracking of the 3D point clouds. The method is tested on two five-minute video sequences captured at a public event with a moderate density of pedestrians and heavy occlusions. The counting performance is compared to the manually annotated ground truth and shows success rates of 95.4% and 99.1% for the two sequences. PMID:26742047

  6. Retrograde crossing for chronic total occlusion lesions: the Japanese way.

    PubMed

    Takano, Masamichi; Mizuno, Kyoichi

    2008-01-01

    Percutaneous coronary intervention (PCI) for chronic total occlusion (CTO) lesions remains one of the major challenges in the field of interventional cardiology. Crossing guidewires through the CTO lesions has been conventionally performed from the proximal arteries to the lesions as an antegrade approach. To date, a retrograde approach, to penetrate PCI devices including guidewires and balloons into the distal end of CTO lesions via collateral vessels or coronary artery bypass grafts, has been attempted in order to achieve procedural success. With introduction of the retrograde approach for treatments of CTO lesions, several kinds of devices, techniques, and strategies have been developed. Although the techniques and strategies for the retrograde approach have not been worldwide accepted to interventional cardiologists, we introduce a way to obtain recanalization of the CTO lesions using the retrograde approach in this article. PMID:19276488

  7. Stent Recanalization of Chronic Portal Vein Occlusion in a Child

    SciTech Connect

    Cwikiel, Wojciech; Solvig, Jan; Schroder, Henrik

    2000-07-15

    An 8-year-old boy with a 21/2 year history of portal hypertension and repeated bleedings from esophageal varices, was referred for treatment. The 3.5-cm-long occlusion of the portal vein was passed and the channel created was stabilized with a balloon-expandable stent; a portosystemic stent-shunt was also created. The portosystemic shunt closed spontaneously within 1 month, while the recanalized segment of the portal vein remained open. The pressure gradient between the intrahepatic and extrahepatic portal vein branches dropped from 17 mmHg to 0 mmHg. The pressure in the portal vein dropped from 30 mmHg to 17 mmHg and the bleedings stopped. The next dilation of the stent was performed 12 months later due to an increased pressure gradient; the gastroesophageal varices disappeared completely. Further dilation of the stent was planned after 2, 4, and 6 years.

  8. Combined branch retinal vein and artery occlusion in toxoplasmosis.

    PubMed

    Aggio, Fabio Bom; Novelli, Fernando José de; Rosa, Evandro Luis; Nobrega, Mário Junqueira

    2016-01-01

    A 22-year-old man complained of low visual acuity and pain in his left eye for five days. His ophthalmological examination revealed 2+ anterior chamber reaction and a white, poorly defined retinal lesion at the proximal portion of the inferotemporal vascular arcade. There were retinal hemorrhages in the inferotemporal region extending to the retinal periphery. In addition, venous dilation, increased tortuosity, and ischemic retinal whitening along the inferotemporal vascular arcade were also observed. A proper systemic work-up was performed, and the patient was diagnosed with ocular toxoplasmosis. He was treated with an anti-toxoplasma medication, and his condition slowly improved. Inferior macular inner and middle retinal atrophy could be observed on optical coherence tomography as a sequela of ischemic injury. To our knowledge, this is the first report of combined retinal branch vein and artery occlusion in toxoplasmosis resulting in a striking and unusual macular appearance. PMID:27463632

  9. Pedestrian Counting with Occlusion Handling Using Stereo Thermal Cameras

    PubMed Central

    Kristoffersen, Miklas S.; Dueholm, Jacob V.; Gade, Rikke; Moeslund, Thomas B.

    2016-01-01

    The number of pedestrians walking the streets or gathered in public spaces is a valuable piece of information for shop owners, city governments, event organizers and many others. However, automatic counting that takes place day and night is challenging due to changing lighting conditions and the complexity of scenes with many people occluding one another. To address these challenges, this paper introduces the use of a stereo thermal camera setup for pedestrian counting. We investigate the reconstruction of 3D points in a pedestrian street with two thermal cameras and propose an algorithm for pedestrian counting based on clustering and tracking of the 3D point clouds. The method is tested on two five-minute video sequences captured at a public event with a moderate density of pedestrians and heavy occlusions. The counting performance is compared to the manually annotated ground truth and shows success rates of 95.4% and 99.1% for the two sequences. PMID:26742047

  10. Anterior segment ischemia secondary to carotid occlusive disease.

    PubMed

    Mills, R P

    1989-09-01

    The ischemic signs of carotid occlusive disease in the anterior segment can be summarized as follows: vasodilation in the conjunctiva, episclera, and iris; neovascularization in the iris and the anterior chamber angle with consequent neovascular glaucoma, with or without elevation of intraocular pressure; and noninflammatory uveitis with corneal edema, keratitic precipitates, flare and cells in the anterior chamber, and late development of cataract. A questionnaire was sent to neuro-ophthalmology and glaucoma specialists regarding their perceptions of this condition. On average, approximately 1 case per specialist per year was seen. One third of the respondents had seen significant ocular pressure increase in patients with rubeosis following successful vascular surgery. Most felt that panretinal photocoagulation, though not as effective as in diabetic rubeosis, did cause regression of iris and angle neovascularization. The visual prognosis following all types of treatment was not good and was insufficient to justify a clear recommendation about the advisability of aggressive management of this condition. PMID:2529282

  11. Antiphospholipid Syndrome and Vascular Ischemic (Occlusive) Diseases: An Overview

    PubMed Central

    2007-01-01

    Antiphospholipid syndrome (APS) is primarily considered to be an autoimmune pathological condition that is also referred to as "Hughes syndrome". It is characterized by arterial and/or venous thrombosis and pregnancy pathologies in the presence of anticardiolipin antibodies and/or lupus anticoagulant. APS can occur either as a primary disease or secondary to a connective tissue disorder, most frequently systemic lupus erythematosus (SLE). Damage to the nervous system is one of the most prominent clinical constellations of sequelae in APS and includes (i) arterial/venous thrombotic events, (ii) psychiatric features and (iii) other non-thrombotic neurological syndromes. In this overview we compare the most important vascular ischemic (occlusive) disturbances (VIOD) with neuro-psychiatric symptomatics, together with complete, updated classifications and hypotheses for the etio-pathogenesis of APS with underlying clinical and laboratory criteria for optimal diagnosis and disease management. PMID:18159581

  12. Myocardial viability in coronary artery chronic total occlusion.

    PubMed

    Vefali, Huseng; Manda, Yugandhar; Shirani, Jamshid

    2015-01-01

    Coronary artery chronic total occlusion (CTO) has rapidly become a popular target of percutaneous coronary intervention (PCI). Technical and technological advances required for approaching these anatomically complex and challenging lesions have progressed at an extraordinary pace and have led to amazing success rates. Patient selection, however, has primarily focused on patient symptoms, lesion characteristics, as well as the state of collateral circulation. Multiple national and international registries have been established to follow the progress of percutaneous CTO recanalization and have provided valuable information. Concern, however, exists that this challenging procedure will become the "standard of care" before its effectiveness and appropriateness is tested in prospective controlled trials. This manuscript reviews the current state of patient selection and the need for careful assessment of the presence and extent of myocardial viability prior to lengthy, resource-intensive, and potentially high-risk procedures. PMID:25413581

  13. Longitudinal relationship between incisal occlusion and incisal tooth wear.

    PubMed

    Silness, J; Johannessen, G; Røynstrand, T

    1993-02-01

    The purpose of the study was to evaluate the longitudinal relationship between incisal wear of central incisors and the size of vertical overbite (OB) and horizontal overjet (OJ). Stone casts of 51 subjects were used for the determinations. Casts were obtained when the subjects were 15 and 27 years old. Statistical analysis was performed with the t test for paired samples, the chi-square test of association. Pearson's product moment correlation coefficient, and Spearman's rank correlation coefficient. Both overbite and overjet diminished after 12 years, and incisal wear increased. It was concluded that increase in age, incisal wear, vertical overbite and incisal occlusion (OB/OJ) are clinical predictors of wear of maxillary and mandibular central incisors in adolescents. PMID:8451919

  14. A computer-aided automated methodology for the detection and classification of occlusal caries from photographic color images.

    PubMed

    Berdouses, Elias D; Koutsouri, Georgia D; Tripoliti, Evanthia E; Matsopoulos, George K; Oulis, Constantine J; Fotiadis, Dimitrios I

    2015-07-01

    The aim of this work is to present a computer-aided automated methodology for the assessment of carious lesions, according to the International Caries Detection and Assessment System (ICDAS II), which are located on the occlusal surfaces of posterior permanent teeth from photographic color tooth images. The proposed methodology consists of two stages: (a) the detection of regions of interest and (b) the classification of the detected regions according to ICDAS ΙΙ. In the first stage, pre-processing, segmentation and post-processing mechanisms were employed. For each pixel of the detected regions, a 15×15 neighborhood is used and a set of intensity-based and texture-based features were extracted. A correlation based technique was applied to select a subset of 36 features which were given as input into the classification stage, where five classifiers (J48, Random Tree, Random Forests, Support Vector Machines and Naïve Bayes) were compared to conclude to the best one, in our case, to Random Forests. The methodology was evaluated on a set of 103 digital color images where 425 regions of interest from occlusal surfaces of extracted permanent teeth were manually segmented and classified, based on visual assessments by two experts. The methodology correctly detected 337 out of 340 regions in the detection stage with accuracy of detection 80%. For the classification stage an overall accuracy 83% is achieved. The proposed methodology provides an objective and fully automated caries diagnostic system for occlusal carious lesions with similar or better performance of a trained dentist taking into consideration the available medical knowledge. PMID:25932969

  15. Subintimal Angioplasty for Peripheral Arterial Occlusive Disease: A Systematic Review

    SciTech Connect

    Met, Rosemarie Lienden, Krijn P. Van; Koelemay, Mark J. W.; Bipat, Shandra; Legemate, Dink A.; Reekers, Jim A.

    2008-07-15

    The objective of this study was to summarize outcomes of subintimal angioplasty (SA) for peripheral arterial occlusive disease. The Cochrane Library, Medline and Embase databases were searched to perform a systematic review of the literature from 1966 through May 2007 on outcomes of SA for peripheral arterial occlusive disease of the infrainguinal vessels. The keywords 'percutaneous intentional extraluminal revascularization,' 'subintimal angioplasty,' 'peripheral arterial disease,' 'femoral artery,' 'popliteal artery,' and 'tibial artery' were used. Assessment of study quality was done using a form based on a checklist of the Dutch Cochrane Centre. The recorded outcomes were technical and clinical success, primary (assisted) patency, limb salvage, complications, and survival, in relation to the clinical grade of disease (intermittent claudication or critical limb ischemia [CLI] or mixed) and location of lesion (femoropopliteal, crural, or mixed). Twenty-three cohort studies including a total of 1549 patients (range, 27 to 148) were included in this review. Methodological and reporting quality were moderate, e.g., there was selection bias and reporting was not done according to the reporting standards. These and significant clinical heterogeneity obstructed a meta-analysis. Reports about length of the lesion and TASC classification were too various to summarize or were not mentioned at all. The technical success rates varied between 80% and 90%, with lower rates for crural lesions compared with femoral lesions. Complication rates ranged between 8% and 17% and most complications were minor. After 1 year, clinical success was between 50% and 70%, primary patency was around 50% and limb salvage varied from 80% to 90%. In conclusion, taking into account the methodological shortcomings of the included studies, SA can play an important role in the treatment of peripheral arterial disease, especially in the case of critical limb ischemia. Despite the moderate patency

  16. Different Imaging Strategies in Patients With Possible Basilar Artery Occlusion

    PubMed Central

    Beyer, Sebastian E.; Hunink, Myriam G.; Schöberl, Florian; von Baumgarten, Louisa; Petersen, Steffen E.; Dichgans, Martin; Janssen, Hendrik; Ertl-Wagner, Birgit; Reiser, Maximilian F.

    2015-01-01

    Background and Purpose— This study evaluated the cost-effectiveness of different noninvasive imaging strategies in patients with possible basilar artery occlusion. Methods— A Markov decision analytic model was used to evaluate long-term outcomes resulting from strategies using computed tomographic angiography (CTA), magnetic resonance imaging, nonenhanced CT, or duplex ultrasound with intravenous (IV) thrombolysis being administered after positive findings. The analysis was performed from the societal perspective based on US recommendations. Input parameters were derived from the literature. Costs were obtained from United States costing sources and published literature. Outcomes were lifetime costs, quality-adjusted life-years (QALYs), incremental cost-effectiveness ratios, and net monetary benefits, with a willingness-to-pay threshold of $80 000 per QALY. The strategy with the highest net monetary benefit was considered the most cost-effective. Extensive deterministic and probabilistic sensitivity analyses were performed to explore the effect of varying parameter values. Results— In the reference case analysis, CTA dominated all other imaging strategies. CTA yielded 0.02 QALYs more than magnetic resonance imaging and 0.04 QALYs more than duplex ultrasound followed by CTA. At a willingness-to-pay threshold of $80 000 per QALY, CTA yielded the highest net monetary benefits. The probability that CTA is cost-effective was 96% at a willingness-to-pay threshold of $80 000/QALY. Sensitivity analyses showed that duplex ultrasound was cost-effective only for a prior probability of ≤0.02 and that these results were only minimally influenced by duplex ultrasound sensitivity and specificity. Nonenhanced CT and magnetic resonance imaging never became the most cost-effective strategy. Conclusions— Our results suggest that CTA in patients with possible basilar artery occlusion is cost-effective. PMID:26022634

  17. Intestinal disaccharidase activity following pancreatic duct occlusion in the rat.

    PubMed

    Hauer-Jensen, M; Christensen, K; Wilson, H D; Schedl, H P

    1987-01-01

    The influence of pancreatic secretions on growth and brush-border enzyme activity, throughout the entire small intestine, was examined in the rat. Pancreatic secretions were excluded from the gut lumen by stapling the pancreatic ducts, without interruption of bile flow. The entire small intestine was studied as four segments; the duodenum and three distal segments of equal length. Weight of intestine and mucosa, and mucosal sucrase, isomaltase, lactase, and alkaline phosphatase activity were measured 10-15 days following pancreatic duct occlusion, or sham-operation. The duodenum of pancreatic duct-occluded animals exhibited significant hypertrophy. In general, specific and total disaccharidase activities were greater in duct-occluded animals than in controls throughout the intestine. The increase was more pronounced in distal than in proximal segments. The sucrase/isomaltase ratio was significantly greater in pancreatic duct-occluded animals than in controls in the two distal segments. Alkaline phosphatase activity was not affected by pancreatic duct occlusion. The greater relative increase of disaccharidase activities and sucrase/isomaltase activity ratios in the distal segments of duct-occluded animals, indicates a more important regulatory role of pancreatic enzymes in the distal small intestine. It is concluded that regulation of intestinal brush-border enzyme activity by pancreatic secretion is selective for enzyme and site as follows: disaccharidases, but not alkaline phosphatase, are regulated; the sucrase subunit of the sucrase/isomaltase complex is most sensitive to regulation, while lactase is least sensitive; and the regulatory effect on disaccharidases is greater in distal than in proximal intestine. PMID:3114740

  18. In-vitro development of a temporal abutment screw to protect osseointegration in immediate loaded implants

    PubMed Central

    2015-01-01

    PURPOSE In this study, a temporal abutment fixation screw, designed to fracture in a controlled way upon application of an occlusal force sufficient to produce critical micromotion was developed. The purpose of the screw was to protect the osseointegration of immediate loaded single implants. MATERIALS AND METHODS Seven different screw prototypes were examined by fixing titanium abutments to 112 Mozo-Grau external hexagon implants (MG Osseous®; Mozo-Grau, S.A., Valladolid, Spain). Fracture strength was tested at 30° in two subgroups per screw: one under dynamic loading and the other without prior dynamic loading. Dynamic loading was performed in a single-axis chewing simulator using 150,000 load cycles at 50 N. After normal distribution of obtained data was verified by Kolmogorov-Smirnov test, fracture resistance between samples submitted and not submitted to dynamic loading was compared by the use of Student's t-test. Comparison of fracture resistance among different screw designs was performed by the use of one-way analysis of variance. Confidence interval was set at 95%. RESULTS Fractures occurred in all screws, allowing easy retrieval. Screw Prototypes 2, 5 and 6 failed during dynamic loading and exhibited statistically significant differences from the other prototypes. CONCLUSION Prototypes 2, 5 and 6 may offer a useful protective mechanism during occlusal overload in immediate loaded implants. PMID:25932315

  19. Intrabronchial Infusion of Autologous Blood Plus Thrombin for Intractable Pneumothorax After Bronchial Occlusion Using Silicon Spigots

    PubMed Central

    Nakahara, Yasuharu; Kawamura, Tetsuji; Sasaki, Shin; Tsukamoto, Hiroaki; Mochiduki, Yoshiro

    2016-01-01

    Background: Bronchial occlusion therapy using silicon spigots is effective for intractable pneumothorax. However, sometimes the pneumothorax is refractory to bronchial occlusion because of collateral ventilation. For such difficult pneumothoraces, we attempted an intrabronchial infusion of autologous blood plus thrombin to control collateral ventilation and stop air leaks. Methods: We performed bronchial occlusions using silicon spigots in patients with spontaneous pneumothorax secondary to emphysema and refractory to chest drainage, but which was inoperable owing to each patient’s poor surgical candidacy and poor overall health condition. When bronchial occlusion proved ineffective, we undertook intrabronchial infusion of autologous blood plus thrombin, 2 to 4 days after bronchial occlusion. A catheter was inserted into the subpleural area, through a gap between the silicon spigot and the bronchial wall, using a flexible bronchoscope under fluoroscopic guidance. Autologous blood, followed by a thrombin solution, was infused using the catheter. We repeated the same infusion a total of 4 to 6 times while changing the target bronchi. All interventions were performed under local anesthesia. Results: The subjects were 9 men, aged from 61 to 88 years, with smoking histories. Three patients also had interstitial pneumonia, and 6 patients had undergone pleurodesis in vain before bronchial occlusion. For 4of the 9 patients, autologous blood plus thrombin infusions successfully stopped air leaks, and in 3 patients, intrabronchial infusions and pleurodesis halted leaks altogether. Conclusion: Intrabronchial infusion of autologous blood plus thrombin was effective for intractable pneumothoraces that could not be clinically managed, even by bronchial occlusion using silicon spigots. PMID:27454474

  20. GORA: a scoring system for the quantification of risk of graft occlusion.

    PubMed

    Copeland, G P; Edwards, P; Wilcox, A; Wake, P N; Harris, P L

    1994-03-01

    Auditing the outcome from vascular surgery with regard to graft occlusion is made difficult by variations in the type of surgery performed and the case mix. These difficulties are compounded when attempting to compare units. In the present study we have attempted to develop a scoring system to predict the risk of graft occlusion, and thus compensate for these variables. Prospectively collected data from 214 consecutive patients undergoing vascular reconstructive surgery (233 arterial grafts) were analysed. Graft occlusion occurred in 82 patients (35.2%). Using a multivariate linear regression analysis of these data a five-factor, five-grade scoring system has been devised (GORA: Graft Occlusive Risk Assessment). Logistic regression analysis of the observed risk of occlusion with this derived score produced the following relationship between the odds ratio of occlusive risk and GORA score: (logeR/1 - R = (0.229 x score) - 4.165). The score was then validated in a different group of 186 patients (196 arterial grafts). In both groups the score was found to predict accurately the risk of graft occlusion (P < 0.001). There was no significant difference in the receiver operating characteristic curves between the estimation and validation groups. PMID:8154808

  1. Comparison of NIRS, laser Doppler flowmetry, photoplethysmography, and pulse oximetry during vascular occlusion challenges.

    PubMed

    Abay, T Y; Kyriacou, P A

    2016-04-01

    Monitoring changes in blood volume, blood flow, and oxygenation in tissues is of vital importance in fields such as reconstructive surgery and trauma medicine. Near infrared spectroscopy (NIRS), laser Doppler (LDF) flowmetry, photoplethysmography (PPG), and pulse oximetry (PO) contribute to such fields due to their safe and noninvasive nature. However, the techniques have been rarely investigated simultaneously or altogether. The aim of this study was to investigate all the techniques simultaneously on healthy subjects during vascular occlusion challenges. Sensors were attached on the forearm (NIRS and LDF) and fingers (PPG and PO) of 19 healthy volunteers. Different degrees of vascular occlusion were induced by inflating a pressure cuff on the upper arm. The responses of tissue oxygenation index (NIRS), tissue haemoglobin index (NIRS), flux (LDF), perfusion index (PPG), and arterial oxygen saturation (PO) have been recorded and analyzed. Moreover, the optical densities were calculated from slow varying dc PPG, in order to distinguish changes in venous blood volumes. The indexes showed significant changes (p  <  0.05) in almost all occlusions, either venous or over-systolic occlusions. However, differentiation between venous and arterial occlusion by LDF may be challenging and the perfusion index (PI) may not be adequate to indicate venous occlusions. Optical densities may be an additional tool to detect venous occlusions by PPG. PMID:26963349

  2. A novel method to determine perineal artery occlusion among male bicyclists

    PubMed Central

    Hotaling, James M.; Kathrins, Martin; Baftiri, Amit P.; Freels, Sally; Niederberger, Craig S.

    2015-01-01

    Background. Perineal pressure due to bicycle riding has been associated with erectile dysfunction. We developed a novel method to measure the occlusive force exerted over the perineal arteries and determined perineal artery occlusion by a variety of seat designs. Methods. Doppler ultrasonography facilitated perineal artery localization and determination of the force required for perineal artery occlusion in 20 healthy men. Flexiforce® sensors were affixed over the proximal and distal aspects of the perineal arteries bilaterally. Individuals completed bicycle rides in the road- and stationary-settings with six distinct seat designs, including those with and without an anterior “nose.” Results. The occlusion time proportion of the total ride time was calculated for each trial. The overall occlusion time proportion was 0.59 (95% CI [0.45–0.73]) across all seats and settings. The “no-nose” bicycle seat and the stationary-setting demonstrated significantly lower occlusion proportion times than the traditional nose bicycle seat and road-setting, respectively. However, all bicycle seats yielded an occlusion time proportion of 0.41 or greater. Discussion. Our method of real-time, non-invasive force measurement localized to the perineal arteries may be used to validate future bicycle seat design. It also underscores the significant risk of perineal artery insufficiency in men who are avid bicyclists. This risk may be minimized by using newer “no-nose” bicycle seats. PMID:26713236

  3. A novel method to determine perineal artery occlusion among male bicyclists.

    PubMed

    Parthiban, Sujeeth; Hotaling, James M; Kathrins, Martin; Baftiri, Amit P; Freels, Sally; Niederberger, Craig S

    2015-01-01

    Background. Perineal pressure due to bicycle riding has been associated with erectile dysfunction. We developed a novel method to measure the occlusive force exerted over the perineal arteries and determined perineal artery occlusion by a variety of seat designs. Methods. Doppler ultrasonography facilitated perineal artery localization and determination of the force required for perineal artery occlusion in 20 healthy men. Flexiforce(®) sensors were affixed over the proximal and distal aspects of the perineal arteries bilaterally. Individuals completed bicycle rides in the road- and stationary-settings with six distinct seat designs, including those with and without an anterior "nose." Results. The occlusion time proportion of the total ride time was calculated for each trial. The overall occlusion time proportion was 0.59 (95% CI [0.45-0.73]) across all seats and settings. The "no-nose" bicycle seat and the stationary-setting demonstrated significantly lower occlusion proportion times than the traditional nose bicycle seat and road-setting, respectively. However, all bicycle seats yielded an occlusion time proportion of 0.41 or greater. Discussion. Our method of real-time, non-invasive force measurement localized to the perineal arteries may be used to validate future bicycle seat design. It also underscores the significant risk of perineal artery insufficiency in men who are avid bicyclists. This risk may be minimized by using newer "no-nose" bicycle seats. PMID:26713236

  4. Occlusal enamel complexity in middle miocene to holocene equids (Equidae: Perissodactyla) of North America.

    PubMed

    Famoso, Nicholas A; Davis, Edward Byrd

    2014-01-01

    Four groups of equids, "Anchitheriinae," Merychippine-grade Equinae, Hipparionini, and Equini, coexisted in the middle Miocene, but only the Equini remains after 16 Myr of evolution and extinction. Each group is distinct in its occlusal enamel pattern. These patterns have been compared qualitatively but rarely quantitatively. The processes influencing the evolution of these occlusal patterns have not been thoroughly investigated with respect to phylogeny, tooth position, and climate through geologic time. We investigated Occlusal Enamel Index, a quantitative method for the analysis of the complexity of occlusal patterns. We used analyses of variance and an analysis of co-variance to test whether equid teeth increase resistive cutting area for food processing during mastication, as expressed in occlusal enamel complexity, in response to increased abrasion in their diet. Results suggest that occlusal enamel complexity was influenced by climate, phylogeny, and tooth position through time. Occlusal enamel complexity in middle Miocene to Modern horses increased as the animals experienced increased tooth abrasion and a cooling climate. PMID:24587267

  5. Occlusal Enamel Complexity in Middle Miocene to Holocene Equids (Equidae: Perissodactyla) of North America

    PubMed Central

    Famoso, Nicholas A.; Davis, Edward Byrd

    2014-01-01

    Four groups of equids, “Anchitheriinae,” Merychippine-grade Equinae, Hipparionini, and Equini, coexisted in the middle Miocene, but only the Equini remains after 16 Myr of evolution and extinction. Each group is distinct in its occlusal enamel pattern. These patterns have been compared qualitatively but rarely quantitatively. The processes influencing the evolution of these occlusal patterns have not been thoroughly investigated with respect to phylogeny, tooth position, and climate through geologic time. We investigated Occlusal Enamel Index, a quantitative method for the analysis of the complexity of occlusal patterns. We used analyses of variance and an analysis of co-variance to test whether equid teeth increase resistive cutting area for food processing during mastication, as expressed in occlusal enamel complexity, in response to increased abrasion in their diet. Results suggest that occlusal enamel complexity was influenced by climate, phylogeny, and tooth position through time. Occlusal enamel complexity in middle Miocene to Modern horses increased as the animals experienced increased tooth abrasion and a cooling climate. PMID:24587267

  6. Laser Therapy and Occlusal Stabilization Splint for Temporomandibular Disorders in Patients With Fibromyalgia Syndrome: A Randomized, Clinical Trial.

    PubMed

    Molina-Torres, Guadalupe; Rodríguez-Archilla, Alberto; Matarán-Peñarrocha, Guillermo; Albornoz-Cabello, Manuel; Aguilar-Ferrándiz, María Encarnación; Castro-Sánchez, Adelaida María

    2016-09-01

    Context • Patients with fibromyalgia syndrome (FMS) report frequent and severe symptoms from temporomandibular disorders (TMDs). The appropriate treatment of TMDs remains controversial. No studies have occurred on the efficacy of therapy with a laser or an occlusal stabilization splint in the treatment of TMDs in patients with FMS. Objective • The study intended to investigate the therapeutic effects of laser therapy and of an occlusal stabilization splint for reducing pain and dysfunction and improving the quality of sleep in patients with TMDs and FMS. Design • The research team designed a single-blinded, randomized clinical trial. Setting • The study took place in the research laboratory at the University of Granada (Granada, Spain). Participants • Participants were 58 women and men who had been diagnosed with FMS and TMDs and who were referred from the clinical setting. Intervention • Participants were randomly assigned to the occlusal-splint or the laser group. The laser group received a treatment protocol in which laser therapy was applied to the participant's tender points, and the occlusal-splint group underwent a treatment protocol in which an occlusal stabilization splint was used. Both groups underwent treatment for 12 wk. Outcomes Measures • Pain intensity, widespread pain, quality of sleep, severity of symptoms, active and passive mouth opening, and joint sounds were assessed in both groups at baseline and after the last intervention. The measurements used were (1) a visual analogue scale (VAS), (2) the Widespread Pain Index (WPI), (3) the Symptom Severity Scale (SSS), (4) the Patient's Global Impression of Change (PGIC), (5) the Pittsburgh Quality of Sleep Questionnaire Index (PSQI), (6) an assessment of the number of tender points, (7) a measurement of the active mouth opening, (8) a measurement of the vertical overlap of the incisors, and (9) the measurement of joint sounds during mouth opening and closing. Results • The group X time

  7. Dual-band reactively loaded microstrip antenna

    NASA Technical Reports Server (NTRS)

    Richards, W. F.; Long, S. A.; Davidson, S. E.

    1985-01-01

    A previously derived theory is applied to a microstrip antenna with a reactive load to produce a dual-band radiator. A model consisting of a rectangular patch radiator loaded with a variable length short-circuited coaxial stub was investigated experimentally. Comparisons of theoretical predictions and experimental data are made for the impedance and resonant frequencies as a function of the position of the load, the length of the stub, and the characteristic impedance of the stub.

  8. Differentiating Carotid Terminus Occlusions into Two Distinct Populations Based on Willisian Collateral Status

    PubMed Central

    Lee, Sun-Uk; Hong, Ji Man; Kim, Sun Yong; Bang, Oh Young; Demchuk, Andrew M.; Lee, Jin Soo

    2016-01-01

    Background and Purpose The outcomes of acute internal carotid artery (ICA) terminus occlusions are poor. We classified ICA terminus occlusions into 2 groups according to the occlusion pattern of the circle of Willis and hypothesized that clinical outcomes would significantly differ between them. Methods Consecutive patients with acute ICA terminus occlusions evaluated by baseline computed tomographic angiography were enrolled. We investigated the occlusion patterns in the circle of Willis, retrospectively classified patients into simple ICA terminus occlusion (STO; with good Willisian collaterals from neighboring cerebral circulation) and complex ICA terminus occlusion (CTO; with one or more of A2 anterior cerebral artery, fetal posterior cerebral artery occlusion, or hypoplastic/absent contralateral A1; or with poor collaterals from anterior communicating artery) groups, and compared their baseline characteristics and outcomes. Results The STO group (n=58) showed smaller infarct volumes at 72 hours than the CTO group (n=34) (median, 81 mL [interquartile range, 38-192] vs. 414 mL [193-540], P<0.001) and more favorable outcomes (3-month modified Rankin Scale 0-3, 44.8% vs. 8.8%, P<0.001; 3-month mortality, 24.1% vs. 67.6%, P<0.001). In multivariable analyses, STO remained an independent predictor for favorable outcomes (odds ratio 6.1, P=0.010). Conclusions Favorable outcomes in STO group suggested that the outcomes of acute ICA terminus occlusions depend on Willisian collateral status. Documenting the subtypes on computed tomographic angiography would help predict patient outcome. PMID:26915505

  9. One-year outcome of bevacizumab therapy for chronic macular edema in central and branch retinal vein occlusions in real-world clinical practice in the UK

    PubMed Central

    Lip, Peck Lin; Malick, Huzaifa; Damer, Kenan; Elsherbiny, Samer; Darrad, Kanupriya M; Mushtaq, Bushra; Mitra, Arijit; Stavrou, Panagiota; Yang, Yit

    2015-01-01

    Background The purpose of this study was to investigate the 12-month outcome of macular edema secondary to both chronic and new central and branch retinal vein occlusions treated with intravitreal bevacizumab in the real-life clinical setting in the UK. Methods Retrospective case notes analysis of consecutive patients with retinal vein occlusions treated with bevacizumab in 2010 to 2012. Outcome measures were visual acuity (measured with Snellen, converted into logMAR [logarithm of the minimum angle of resolution] for statistical calculation) and central retinal thickness at baseline, 4 weeks post-loading phase, and at 1 year. Results There were 56 and 100 patients with central and branch retinal vein occlusions, respectively, of whom 62% had chronic edema and received prior therapies and another 32% required additional laser treatments post-baseline bevacizumab. Baseline median visual acuity was 0.78 (interquartile range [IQR] 0.48–1.22) in the central group and 0.6 (IQR 0.3–0.78) in the branch group. In both groups, visual improvement was statistically significant from baseline compared to post-loading (P<0.001 and P=0.03, respectively), but was not significant by month 12 (P=0.058 and P=0.166, respectively); 30% improved by at least three lines and 44% improved by at least one line by month 12. Baseline median central retinal thickness was 449 μm (IQR 388–553) in the central group and 441 μm (IQR 357–501) in the branch group. However, the mean reduction in thickness was statistically significant at post-loading (P<0.001) and at the 12-month time point (P<0.001) for both groups. The average number of injections in 1 year was 4.2 in the central group and 3.3 in the branch group. Conclusion Our large real-world cohort results indicate that bevacizumab introduced to patients with either new or chronic edema due to retinal vein occlusion can result in resolution of edema and stabilization of vision in the first year. PMID:26445525

  10. Acute Central Retinal Vein Occlusion Secondary to Reactive Thrombocytosis after Splenectomy

    PubMed Central

    Oncel Acir, Nursen; Borazan, Mehmet

    2014-01-01

    The diagnosis and treatment of central retinal vein occlusion was reported in a young patient. Central retinal vein occlusion was probably related to secondary to reactive thrombocytosis after splenectomy. The patient was treated with steroids for papilledema and administered coumadin and aspirin. The symptoms resolved, and the findings returned to normal within three weeks. Current paper emphasizes that, besides other well-known thrombotic events, reactive thrombocytosis after splenectomy may cause central retinal vein occlusion, which may be the principal symptom of this risky complication. Thus, it can be concluded that followup for thrombocytosis and antithrombotic treatment, when necessary, are essential for these cases. PMID:25276452

  11. Coiling occlusion of the vertebral artery for a patient with recurrent posterior circulation TIAs.

    PubMed

    Chembala, J; Jadun, C; Natarajan, I; Roffe, C

    2013-02-01

    Recurrent posterior circulation infarcts frequently involve multiple vascular territories, suggesting an embolic source. We describe a patient with left vertebral artery occlusion who had recurrent transient ischaemic attacks due to cerebral embolization originating from the occluded vertebral artery in spite of optimal anticoagulant and antithrombotic treatment. This was successfully managed by coiling occlusion of the vertebral artery with no recurrence of symptoms over one year of follow-up. To our knowledge, this is the first report of coiling occlusion in the treatment of recurrent vertebral artery embolization. PMID:23859172

  12. Life-threatening Cerebral Edema Caused by Acute Occlusion of a Superior Vena Cava Stent

    SciTech Connect

    Sofue, Keitaro Takeuchi, Yoshito Arai, Yasuaki; Sugimura, Kazuro

    2013-02-15

    A71-year-old man with advanced lung cancer developed a life-threatening cerebral edema caused by the acute occlusion of a superior vena cava (SVC) stent and was successfully treated by an additional stent placement. Although stent occlusion is a common early complication, no life-threatening situations have been reported until now. Our experience highlights the fact that acute stent occlusion can potentially lead to the complete venous shutdown of the SVC, resulting in life-threatening cerebral edema, after SVC stent placement. Immediate diagnosis and countermeasures are required.

  13. Influence on collateral flow of recanalising chronic total coronary occlusions: a case-control study

    PubMed Central

    Pohl, T; Hochstrasser, P; Billinger, M; Fleisch, M; Meier, B; Seiler, C

    2001-01-01

    OBJECTIVE—To assess the effect of recanalisation on collateral flow in a case-control study in patients with and without chronic total coronary occlusions.
DESIGN—In 54 patients undergoing percutaneous transluminal coronary angioplasty (PTCA) (mean (SD) age 61 (6) years), coronary collateral flow was measured by intracoronary pressure or Doppler guide wires at the end of repeated balloon occlusions. Coronary collateral flow index (collateral flow relative to normal antegrade flow) during the first two balloon inflations in 27 patients with a chronic total occlusion (occlusion group) was compared with that of 27 patients matched for age, sex, and collateral flow index at the first occlusion and with a coronary artery diameter stenosis ⩽ 80% (stenosis group).
RESULTS—Following revascularisation, collateral flow index decreased in 17 of the patients in the occlusion group (63%) and in eight of the patients in the stenosis group (30%) (p = 0.03 between groups). The overall change of collateral flow index between the first and the second balloon occlusion was −0.04 (0.01) in the occlusion group (p = 0.07 for paired comparison; from 0.29 (0.17) to 0.25 (0.14)), and +0.02 (0.06) in the stenosis group (p = 0.06 for paired comparison; from 0.27 (0.13) to 0.30 (0.15)). The trend to collateral enhancement in the stenosis group differed significantly from the occlusion group (p = 0.01).
CONCLUSIONS—While repeated coronary balloon occlusions induce collateral recruitment in the majority of patients with moderate stenoses, recanalisation of chronic total coronary occlusions is more often associated with collateral flow reduction. A later decrease in collateral flow by involution of collateral channels cannot be excluded by this study but has not been reported so far.


Keywords: coronary collateral circulation; coronary occlusion; revascularisation; collateral damage PMID:11559686

  14. Pregnancy management for a patient with graft occlusion after right iliac artery bypass surgery.

    PubMed

    Nakae, Ruriko; Matsuzaki, Shinya; Egawa-Takata, Tomomi; Mimura, Kazuya; Kanagawa, Takeshi; Kimura, Tadashi

    2015-06-01

    We describe an extremely rare case of a pregnant woman who had a successful delivery despite developing bypass graft occlusion after right external iliac bypass surgery. External and common iliac artery bypass surgery is often performed when arteriosclerosis obliterans or thromboangiitis obliterans result in iliac artery occlusion or when revascularization is required because of iliac artery injury. Because arteriosclerosis obliterans and thromboangiitis obliterans rarely develop in young women or girls, most physicians have little experience with graft occlusion after iliac artery bypass surgery. Here we describe and discuss the published work pertaining to this extremely rare case. PMID:25511914

  15. Successful Recanalization of a Longstanding Right Common Iliac Artery Occlusion with a Radiofrequency Guidewire

    SciTech Connect

    Tapping, C. R.; Uri, I. F.; Dixon, S.; Bratby, M. J.; Anthony, S.; Uberoi, R.

    2012-10-15

    We describe a case of successful recanalization of a longstanding right common iliac occlusion with a radiofrequency (RF) guidewire. The patient had been symptomatic with claudication for 3 years, and a preliminary attempt to cross the lesion using conventional techniques proved unsuccessful. Using low and medium intensity RF pulses and a PowerWire, a tract through the occlusion was established, which allowed subsequent stenting with an excellent angiographic result and a good immediate clinical response. We propose this as a useful technique in the peripheral arterial system for occlusive lesions not amenable to traditional recanalization techniques.

  16. De Winter Electrocardiographic Pattern Related with a Non-Left Anterior Descending Coronary Artery Occlusion.

    PubMed

    Montero Cabezas, José M; Karalis, Ioannis; Schalij, Martin J

    2016-09-01

    The electrocardiographic pattern consisting of ST-segment depression and hyperacute T waves in patients with acute chest pain, known as "De Winter pattern," has been related with the occlusion of the proximal left anterior descending artery (LAD). The association of these findings with the involvement of a different coronary artery has not been described. We present a 53-year-old patient with an occlusion of the first diagonal branch and an electrocardiogram showing a "De Winter pattern." The reported case demonstrates that "De Winter pattern" is not exclusively associated with the occlusion of the proximal segment of the LAD. PMID:27592618

  17. Metglas-Elgiloy bi-layer, stent cell resonators for wireless monitoring of viscosity and mass loading

    NASA Astrophysics Data System (ADS)

    Viswanath, Anupam; Green, Scott R.; Kosel, Jürgen; Gianchandani, Yogesh B.

    2013-02-01

    This paper presents the design and evaluation of magnetoelastic sensors intended for wireless monitoring of tissue accumulation in peripheral artery stents. The sensors are fabricated from 28 µm thick foils of magnetoelastic 2826MB Metglas™, an amorphous Ni-Fe alloy. The sensor layer consists of a frame and an active resonator portion. The frame consists of 150 µm wide struts that are patterned in the same wishbone array pattern as a 12 mm × 1.46 mm Elgiloy stent cell. The active portion is a 10 mm long symmetric leaf shape and is anchored to the frame at mid length. The active portion nests within the stent cell, with a uniform gap separating the two. A gold-indium eutectic bonding process is used to bond Metglas™ and Elgiloy foils, which are subsequently patterned to form bi-layer resonators. The response of the sensor to viscosity changes and mass loading that precede and accompany artery occlusion is tested in vitro. The typical sensitivity to viscosity of the fundamental, longitudinal resonant frequency at 361 kHz is 427 ppm cP-1 over a 1.1-8.6 cP range. The sensitivity to mass loading is typically between 63000 and 65000 ppm mg-1 with the resonant frequency showing a reduction of 8.1% for an applied mass that is 15% of the unloaded mass of the sensor. This is in good agreement with the theoretical response.

  18. Toxic tacrolimus levels after application of topical tacrolimus and use of occlusive dressings in two bone marrow transplant recipients with cutaneous graft-versus-host disease.

    PubMed

    Olson, Katherine A; West, Kathleen; McCarthy, Philip L

    2014-06-01

    levels. Based on the findings from our two patients as well as published case reports, systemic absorption appears to increase with greater skin permeability, skin barrier dysfunction, amount of body surface area applied, and use of occlusive dressings. When one or more of these factors are present, it may be prudent to monitor tacrolimus levels. PMID:24700567

  19. 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...

  20. 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...