External Occlusion Research Articles

Can miners' social networks affect their safety commitment? A case study of Chinese coal mining enterprises

Safety commitment is a key factor determining the stability of miners' safe behavior. This study explored safety commitments from the perspective of personnel traits and social networks, extending previous studies on single individual safety commitments. A case survey of social networks, personality traits, and the safety commitment level of six workgroups from coal mining enterprises in China was conducted. The findings demonstrate that: (1) Workgroups exhibited “external occlusion”, and key connecting nodes and the core nodes of each group showed an aggregation of nodes with more openness and conscientiousness. (2) With regard to the network density, a positive relationship exists between network density and safety commitment for groups in the same sub-units; likewise, there are obvious correlations among parts of network parameters and safety commitments, as well as personality traits. (3) The opinion leaders’ commitment to safety reflects that of their workgroup. Meanwhile, when opinion leaders and group chiefs are not the same people, the safety commitment of opinion leaders is higher than that of group chiefs. (4) Homogeneous clusters and heterogeneous clusters of subgroups exist in workgroups and there is a consistent relationship between the safety characteristics of cluster subgroups and the safety commitment level of the whole workgroup. This study extends the theoretical foundation of safety commitments from the perspective of micro-networks and provides a practical inspiration for overcoming inefficient safety management and effectively promoting safety performance in coal companies.

Xen45 gel stent ab interno trimming for ostium occlusion: case report

BackgroundDespite the XEN gel stent low-risk profile, various complications following the implant have been described, including internal and external occlusion, with a consequent postoperative rise in intraocular pressure (IOP). In this case report we aimed to present a XEN45 stent internal occlusion successfully treated by trimming in situ its proximal end with a 25 G vitreous scissors using a bimanual technique.Case presentationA 63-year-old male patient affected by primary open angle glaucoma (IOP = 25 mmHg) and a full thickness macular hole in his right eye, underwent ab-interno Xen gel stent implantation and, 1 month later, a 25 G vitrectomy surgery. Despite a significant IOP reduction after stent implant, 6 days after vitrectomy, IOP increased (25 mmHg) and the conjunctival bleb flattened following occlusion of stent internal ostium by a clot of presumed fibrinous material. The Nd:YAG laser failed to remove the clot, so that we decided to snip a small bit of the proximal end of the Xen tube (about 0,5 mm length) with a 25 G vitreous scissors, using a bimanual technique. In the postoperative day 1 and month 1, the IOP was 8 mmHg and 12 mmHg, respectively. The Anterior Segment OCT confirmed a functional, layered, filtering bleb, and the normal appearance and patency of the XEN proximal segment. No side effects from the intervention were observed.ConclusionsAb interno trimming with vitreous scissors of the occluded proximal end of the XEN stent may represent a safe, rapid and efficient method to restore aqueous humor subconjunctival drainage.

Generative detect for occlusion object based on occlusion generation and feature completing

Detecting the object with external occlusion has always been a hot topic in computer version, while its accuracy is always limited due to the loss of original object information and increase of new occlusion noise. In this paper, we propose a occluded object detection algorithm named GC-FRCN (Generative feature completing Faster RCNN), which consists of the OSGM (Occlusion Sample Generation Module) and OSIM (Occlusion Sample Inpainting Module). Specifically, the OSGM mines and discards the feature points with high category response on the feature map to enhance the richness of occlusion scenes in the training data set. OSIM learns an implicit mapping relationship from occluded feature map to real feature map adversarially, which aims at improving feature quality by repair the noisy object feature. Extensive experiments and ablation studies have been conducted on four different datasets. All the experiments demonstrate the GC-FRCN can effectively detect objects with local external occlusion and has good robustness for occlusion at different scales.

Research on the Performance of a New External Occlusion Device for Pressure Vessel Leakage

Given the advantages and disadvantages of the existing plugging technology, a new type of external sealing device for pressure vessel leakage is proposed, which has the advantages of fast installation speed, small installation resistance, and stronger adaptability to the leakage surface. The connecting rod propulsion mechanism provides power, uses the fluidity of materials in the annular cavity to adapt to the complex curved surface, and carries out real-time monitoring and self-healing of the plugging process. Through the establishment of a finite element model of conventional top pressure plugging and the new type of external sac plugging method, simulation analysis of the leakage point and the pressure distribution around the crack leak has shown that: in the installation process of the new type of external liquid sac plugging device, a pressure-equalizing contact area and a sealing area are formed around the leakage point, and there is no obvious stress concentration phenomenon. When the thickness of the gasket is low, the deformation is uniform, which overcomes the problems of insufficient adaptability of the gasket in the conventional jacking method, and enhances the stability and reliability of emergency plugging.

Hand pose estimation in object-interaction based on deep learning for virtual reality applications

Hand Pose Estimation aims to predict the position of joints on a hand from an image, and it has become popular because of the emergence of VR/AR/MR technology. Nevertheless, an issue surfaces when trying to achieve this goal, since a hand tends to cause self-occlusion or external occlusion easily as it interacts with external objects. As a result, there have been many projects dedicated to this field for a better solution of this problem. This paper develops a system that accurately estimates a hand pose in 3D space using depth images for VR applications. We propose a data-driven approach of training a deep learning model for hand pose estimation with object interaction. In the convolutional neural network (CNN) training procedure, we design a skeleton-difference loss function, which effectively can learn the physical constraints of a hand. Also, we propose an object-manipulating loss function, which considers knowledge of the hand-object interaction, to enhance performance.In the experiments we have conducted for hand pose estimation under different conditions, the results validate the robustness and the performance of our system and show that our method is able to predict the joints more accurately in challenging environmental settings. Such appealing results may be attributed to the consideration of the physical joint relationship as well as object information, which in turn can be applied to future VR/AR/MR systems for more natural experience.

Treatment of an external iliac artery chronic total occlusion using alternate access sites

BackgroundWith the advent of endovascular techniques, alternate sites such as the pedal and radial arteries can now be accessed when treating peripheral arterial disease to reduce procedural complications, shorten recovery time, and improve patient comfort. However, a paucity of literature exists on the availability of support devices that can be utilized during challenging cases.Case presentationA 70 year-old female patient presented for evaluation of severe lifestyle-limiting left-sided claudication refractory to maximal medical therapy. Angiography revealed a chronic total occlusion of the left external iliac artery, which was treated successfully by percutaneous intervention via a primary transpedal approach and with the assistance of the Outback® Elite re-entry device. The patient was discharged 2 h after the procedure and reported significant symptom improvement at follow-up.ConclusionThis case highlights a newly adopted endovascular approach through an alternate access site and illustrates how the Outback® Elite device can be used as an adjunctive tool in the treatment of complex lower-extremity vascular lesions.

Patient selection and methods of surgical left atrial appendage exclusion.

The left atrial appendage (LAA) is a major source of thromboembolism, particularly in patients with atrial fibrillation (AF). LAA exclusion has arisen as a method of stroke prophylaxis in high-risk patients who have failed medical management, in whom medical management is contraindicated, and in those undergoing concomitant cardiac surgery. Percutaneous LAA exclusion with devices such as the Watchman has been described extensively in the cardiology literature, but surgical exclusion is less often discussed. Several techniques exist for surgical LAA exclusion, including appendage excision (removal), internal ligation from within the left atrium (LA), and external occlusion without opening the LA. The decision of which surgical technique to employ is dependent upon individual patient characteristics including risk factors, surgical history, and appendage anatomy. This paper discusses patient selection for surgical LAA exclusion and methods of surgical exclusion for the non-cardiac surgery medical practitioner.

INFLUENCE OF COMBINATION THERAPY ON THE FUNCTIONAL CONDITION OF VASCULAR ENDOTHELIAL IN PATIENTS WITH ARTERIAL HYPERTENSION WITH SITUATION DEPRESSION LIVING ON DONBASS

The article presents the results of the effect on the vasodilating function of the endothelium of complex treatment of patients with arterial hypertension stage II with identified situational depression living in Donbas. Additional inclusion in the standard antihypertensive pharmacotherapy of the psychotherapeutic complex auto-training + functional music + L-arginine (0,75 once a day) has been shown to effectively eliminate vascular endothelial dysfunction, which was manifested by a change in the diameter of the brachial artery (p 0,001) in response to an increase in speed blood flow (p 0,05) after external occlusion in this group of patients after 24 weeks of treatment is similar to the change in healthy volunteers (p 0,05).

Superior vena cava syndrome after cardiac surgery

Superior vena cava (SVC) syndrome is a group of symptoms caused by obstruction of the SVC at the junction of the right atrium. This obstruction was found to be caused by either external compression or internal occlusion. It leads then to impaired venous drainage into the heart, which will in turn reduce the preload and consequently the cardiac output that might be fatal at some stage. On the flip side, it causes blood engorgement of the upper half of the body resulting in swelling and increased pressures. SVC syndrome may happen acutely in relation to cardiac surgery as a less frequent complication. It might be then caused by mechanical obstruction by a retractor, improper placement of venous cannula, thrombus formation on top of indwelling catheters or pacemaker wires, or overflow following ‘Glenn’ surgery in pediatrics. Diagnosis of the SVC syndrome should involve a high index of suspicion in the context of cardiac surgery especially that the manifestations are not classic in all cases. So, once the manifestations of the syndrome start to appear, prompt actions should be taken to confirm the diagnosis and to start treatment to avoid hemodynamic instability resulting from the dramatic decrease in preload, taking into consideration the limited time available for the collateral drainage (e.g. from azygos, hemiazygos, or internal mammary veins) to develop and bypass the obstruction. Exploring different causes of developing SVC syndrome after cardiac surgery would help early diagnosis and management, which could be lifesaving in many scenarios.

Extracorporeal Pringle for laparoscopic liver resection.

A primary concern during laparoscopic liver resection (lapLR) is hemorrhage during parenchymal transection. Intermittent pedicle clamping is an effective method to minimize blood loss during open liver surgery; however, inflow occlusion techniques are challenging to reproduce during laparoscopy. The purpose of this study is to describe the safety and efficacy of a facile method for Pringle maneuver during lapLR. 154 patients who underwent lapLR from 2007 to 2013 were retrospectively reviewed. For Pringle, the hepatoduodenal ligament is encircled with an umbilical tape which is externalized through a flexible Rumel tourniquet running alongside a port used for the operation. The internal end of the catheter is close to the pedicle and the external end is extracorporeal, allowing for easy external occlusion. Patients who underwent Pringle Maneuver (PM, n = 88) were compared to patients who had "No Occlusion" (NO, n = 66) with respect to patient characteristics, operative outcomes, changes in postoperative liver function, and complications. Annual placement of the tourniquet and vascular occlusion increased from 35.7 to 82.8 % (p = 0.004) and 21.4 to 62.1 % (p = 0.02), respectively. Median occlusion time was 24 min (IQR 15-34.3, min 5, max 70). Peak transaminase levels were comparable between groups (AST 298 ± 32 vs 405 ± 47 U/L, p = 0.15; ALT 272 ± 27 vs 372 ± 34 U/L, p = 0.14, NO and PM, respectively). Postoperative transaminase and bilirubin levels for both groups were not significantly different with similar recovery to baseline. Subgroup analysis of cirrhotic patients who underwent Pringle demonstrated similar transaminase profiles compared to non-cirrhotic patients. There were two conversions (1.3 %) and postoperative 30-day mortality was 0.65 %. Extracorporeal tourniquet placement in lapLR is a quick and safe method of gaining control for inflow occlusion. Routine adoption of laparoscopic Pringle maneuver facilitates low conversion rates without liver injury.

G84(P) Superior mesenteric artery (SMA) syndrome: An unusual cause of proximal intestinal obstruction

BackgroundSMA Syndrome is characterised by a decreased acuity of the angle between aorta and SMA due to the loss of mesenteric fat between the SMA and aorta resulting in compression...

Effect of procedure volume on outcomes after iliac artery angioplasty and stenting (Br J Surg 2013: 100: 1189–1196)

Goode and colleagues report on the relationship between the annual caseload (volume) of iliac artery angioplasties undertaken within English hospitals and the outcome of these interventions. The work is significant in its role to benchmark national radiological outcomes. The key finding was that there appeared to be little relationship between volume and outcome in either elective or emergency procedures when assessing mortality, length of stay or procedural complication rates. Second, women and older patients fared worse from intervention, most impressively in the elective setting. There have been few previous attempts to quantify volume–outcome relationships in the radiological literature, other than for carotid artery stenting, which is highly volume-dependent1. This is due to difficulties in defining appropriate outcome measures, and procedural heterogeneity. In undertaking these analyses, the authors faced a number of challenges that are complex to resolve using administrative data and cloud interpretation of the results. One major confounder is the lack of granularity within the data that makes it impossible to determine the case mix undertaken in individual units. For example, a full-length external and common iliac occlusion would be expected to have a worse outcome than a short common iliac stenosis, but would be coded similarly. There are also complexities in outcome selection. Although mortality and length of stay are valid outcomes for procedures such as open aneurysm repair2, as the authors demonstrated, few patients die or have prolonged admissions after elective iliac intervention. The most appropriate measures, such as health status and symptom-based patient-reported outcome measures, are unlikely to be realistic endpoints in the near future.

Elective minimally invasive coronary artery bypass: Shunt or tournique occlusion? Assessment of a protective role of perioperative left anterior descending shunting on myocardial damage. A prospective randomized study

BackgroundTo determine impact of intraluminal-left anterior descending shunt to prevent myocardial damage in minimally invasive coronary artery bypass.Methods38 patients were randomly assigned to external tournique occlusion (n = 19) or intraluminal-left anterior descending shunt group (n = 19). Blood samples for cardiac troponin T were collected at 30 minutes prior to, 6 and 24 hours after surgery.ResultsOne patient in external tournique occlusion and two patients in intraluminal-left anterior descending shunt group were excluded from futher analysis due to preoperative cardiac troponin T level above the 99th-percentile. Postoperatively, each six patients in external tournique occlusion (33.3%) and intraluminal-left anterior descending shunt (35.3%) group were above the 99th-percentile. Two patients from each group (external tournique occlusion group 11.1% vs. intraluminal-left anterior descending shunt group 11.8%) had peak values above 10-% coeficient of variation cutoff (p = 1). There were no significant differences in between both groups at all studied timepoints.ConclusionThere was no protective effect of intraluminal shunting on myocardial damage compared to short-term tournique occlusion. It is upon the surgeon's discretion which method may preferrably be used to achieve a bloodless field in grafting of the non-occluded left anterior descending in minimally invasive coronary artery bypass.

Initial etiological research of intracranial dural arteriovenous fistulas

Objective To investigate the pathogenesis of intracranial dural arteriovenous fistula, with a focus on the role of angiogenic factors and chronic brain hypoperfusion in it. Methods 120 Sprague-Dawley rats were randomly divided into 4 groups: 1) Group A (n=25) , sham operation; 2) Group B (n = 25), thrombosis of the sagittal sinus; 3) Group C (n = 35), anastomosis of the right common carotid artery(CCA) to the external jugular vein(EJV) and occlusion of the proximate-cardiac end of the transverse sinus on the left; 4) Group D(n =35) , procedures done as Group C and thrombosis of the sagittal sinus was added. Mean arterial pressure, sinus pressure, blood flow of the brain were monitored during the operation and again tested 1, 2, 4, 12 weeks after operation in subgroups of animals, respectively. Histological examination was used to test the distribution and concentration of VEGF and MMP-9 in dura mater, arachnoid membrane, cortex and basal ganglia. Perfusion MRI of the brain was done to compare blood flow in different site of the brain. Results In group C and D, the mean blood pressure decreased soon after operation, and the sinus pressure elevated to (28.55±4. 92) mm Hg and kept stable at (22. 34 ±3.24) mm Hg 4 weeks later. The blood flow of the brain went down significantly after operation in group C and D, with markedly reduction in the right occipital lobe versus any of the other sites. Two weeks later the blood flow had returned to the normal level in the left side but remained abnormal in the right occipital lobe. Perfusion MRI found higher blood volume and longer mean time to enhance in the right occipital lobe, than in its contralateral side. Immunohistological stain of VEGF was positive in basal ganglia, right occipital lobe and arachnoid membrane one week after operation, but weakened in basal ganglia two weeks later. VEGF expression was weak in dura mater one week after operation, but became strongly positive from the 4th to 12th week after operation. The angiogenesis was prominent in the dura mater 12 weeks after operation in group C and D but negative or obscure in group A and B. Conclusions High sinus pressure was critical for angiogenesis of dura mater. Chronic brain hypoperfusion, which will elevate the expression of VEGF and MMP-9, is an important step from the progression of venous sinus pertension to DAVF formation. Key words: Dura arteriovenous fistula; Model; Rats

Shunt or Snare: Coronary Endothelial Damage due to Hemostatic Devices for Beating Heart Coronary Surgery

Occlusion of coronary arteries during off-pump coronary bypass operations bears the potential for endothelial injury. The aim of this study was to elucidate the effects of hemostatic devices on the beating heart in human coronaries by means of scanning electron microscopy. The coronary arteries of 9 patients with dilated cardiomyopathy and 13 with ischemic heart disease undergoing heart transplantation were handled with intracoronary shunts as well as external snaring techniques on a beating heart, after cannulation but before starting cardiopulmonary bypass. Adjacent noninstrumented coronary artery segments served as controls. Integrity of endothelial lining was observed with scanning electron microscopy. Nearly all coronary artery segments manipulated with a shunt exhibited a severe injury with extensive endothelial denudation. Endothelial injury was significantly higher after manipulation with intracoronary shunts compared with external occlusion devices (p < 0.001) or control specimens (p < 0.001). Plaque rupture was apparent in 3 samples. Manipulation of human coronary arteries during off-pump operations leads to endothelial denudation and plaque rupture. From this investigation we conclude that insertion of intracoronary shunts during beating heart operations leads to severe endothelial denudation in human coronary arteries. We therefore recommend using shunts selectively in cases where critical ischemia or technical difficulties due to anatomic conditions are expected during anastomosis. The clinical significance of these structural damages has to be further investigated with clinical trials.

Black Tea Improves Endothelial Function in Renal Transplant Recipients

Background Endothelial damage and dysfunction are commonplace in renal transplant recipients. Impaired endothelial function is an important contributor to cardiovascular diseases. We hypothesized that short-term black tea consumption may improve endothelium-dependent arterial dilation in kidney recipients. Methods Fifteen recipients were studied on an outpatient basis in a single, university-affiliated clinic. Inclusion criteria were stable and good allograft function. The main exclusion criteria were uncontrolled hypertension, smoking, alcohol consumption, coffee drinking, diabetes mellitus, and coronary artery disease, or a history of upper limb vascular manipulations. After overnight fasting, the brachial artery diameter (BAD) was measured at the end of diastole using an ultrasound machine before (basal BAD) and 1 minute after temporary (∼3 minutes) external occlusion (posthyperemia BAD). Flow-mediated vasodilation (FMV) and percent of FMV (FMV%) were calculated by appropriate formula. FMV and FMV% were determined at baseline and 2 hours after consuming 0.5 L freshly brewed black tea. For control, the study was repeated for each patient the next day and FMV and FMV% were determined before and 2 hours after consuming 0.5 L of water. Results The men age of patients was 37.2 ± 9.7 years (range, 25 to 50) with a male:female ratio of 3:2. Patients were 26.8 ± 10.6 months postrenal transplantation. Black tea consumption significantly increased posthyperemia BAD, FMV, and FMV% ( P < .05). However, water consumption did not alter the basal or posthyperemia BAD, FMV, or FMV% ( P > .05). Conclusion Based on our study, short-term consumption of black tea may improve endothelial function and endothelium-dependent arterial vasodilation in renal transplant recipients.

Osteonecrosis of the hip

Osteonecrosis of the hip is the final common pathway for a group of disorders that results in ischemia of the femoral head. Etiologies include disruption of vessels, external vascular occlusion, embolization, thrombosis, cytotoxicity, and idiopathic causes. As a result of the ischemia cell death occurs and the bone is weakened leading to collapse and eventual degenerative changes to the hip. Early diagnosis is crucial for the successful treatment of osteonecrosis. Unfortunately, most patients' conditions result in total hip arthroplasty. Here we review the etiology, diagnosis and current treatment options.

Venous obstruction in healthy limbs: a model for chronic compartment syndrome?

Chronic exertional compartment syndrome (CECS) in the anterior tibial (AT) compartment is generally believed to be the result of reduced venous blood flow caused by restrictive compartments and increased intramuscular pressures. If this is so, then restricting venous flow in the muscles of healthy subjects during exercise should mimic CECS. This hypothesis was tested in 10 control subjects (aged 19-41 yr, five males) with and without external venous occlusion induced by a sphygmomanometer cuff fitted just below the knee and inflated to 80 mm Hg. Twenty CECS patients (20-39 yr, 16 males) were studied without external occlusion. Subjects performed intermittent, isometric maximal voluntary contractions (MVC) of the AT for 20 min (1.6-s contractions, 0.5 duty cycle). MVC, tetanic force (2 s at 50 Hz), muscle thickness (ultrasound imaging), and pain were measured during exercise and 10 min of recovery. Venous occlusion in the controls induced greater pain, fatigue, and increase in muscle thickness (P < 0.01). Initially the patients fatigued more slowly than the occluded controls, but at the end of exercise, the fatigue and pain were similar in these two groups. The controls showed a greater increase in muscle size (P = 0.01). Recovery was similar in all three groups, although the size of the patients' muscles recovered rather more slowly. External venous occlusion of the AT muscles in control subjects induces changes very similar to those of CECS patients, although the different time courses indicate that different processes are involved. The AT compartment of CECS patients is capable of distension.

Objective measurement of nasal airway dimensions using acoustic rhinometry: methodological and clinical aspects.

Nasal congestion is an important symptom in many diseases of the upper airways. Nasal congestion may also affect personal well-being and quality of life. Furthermore, as the nasal mucosa is the first part of the airways in contact with the environment, objective evaluation of nasal congestion or nasal patency is important. Systematic evaluation of nasal patency was described in the last part of the 19th century by Zwaardemaker. Measurement of the pressure drop over the nasal cavity at a passive dow has been described in 1903 by Courtade and is one of first descriptions rhinomanometry. The technique is still in use and computer technology has made the measurements much easier but the method has not yet been accepted for wide clinical use. Acoustic methods have also been used for evaluation of nasal patency. A qualitative method was the hum-test by Spiess (1902), where external occlusion of the nonocciuded side of the nasal cavity is experienced as a change in the timbre of the sound during humming. Acoustic reflections have been used in geophysical investigations especially with regard to search for oil. The use of acoustic reflections from the airways gained special interest in 1960-70 for determining the geometry of the vocal tract shape with regard to speech reconstruction. A method described by A. Jackson (1977) was adopted and for the first time applied to the nasal cavity. The method for determining the cross-sectional area as function of distance in the airways by acoustic reflections is impulse or relatively simple. The incident sound pseudorandom noise in the audible frequency range is compared with the response - the reflections from the airways. Intuitively, if the size of the entrance to the airways is known, the size of the reflections may represent changes of the airway size and the time between reflections may give the distance between the changes, dependent on the speed of sound. In this way it is possible to determine the area as function of distance in the airways. The technique has some assumptions and the major effort has been to validate use in the nose and elucidate aspects with regard to sound loss in the airways and resolution. Therefore, the acoustic reflection technique - named acoustic rhinometry - was compared with other methods like MRI, CT, and rhinomanometry. Allergic and nonallergic subjects were also compared. Acoustic rhinometry showed reasonable correlation with CT in a cadaver and in 10 subjects in comparison with MRI for the first 6 cm of the nasal cavity. Models based on MRI scannings of subjects also showed good correlation for the first 6 cm of the nasal cavity. Posteriorly in the nasal cavity and the epipharynx, differences were found mainly due to 'sound loss' to the paranasal sinuses. Sound loss due to viscous loss or friction at increasing surface/area ratio (the complex geometry in the nose) and loss due to nonrigidity the nasal mucosa were also examined. Neither these factors affected the area-distance function significantly. Acoustic rhinometry seems to reflect the area-distance function in the nose reasonably accurately. In allergic subjects acoustic rhinometry has been used to evaluate hypersensitivity. More pronounced spontaneous variation in nasal mucosa congestion was found in patients suffering from hay fever compared to nonallergic subjects. Furthermore, a tendency to a more swollen mucosa in the allergic subjects compared to the normal state, and increased sensitivity to histamine was found. This and reduction in swelling of the mucosa in allergic subjects during nasal steroid treatment out of the pollen season indicate an ongoing inflammatory process or hypersensitivity in allergic subjects out ot the pollen season. During allergen challenge the change in nasal cavity dimension as well as inflammation may affect olfaction in hay fever patients. Acoustic rhinometry has not only been used to examine hay fever patients but in many different aspects of rhinology. Since the introduction of the acoustic reflection technique in the nose more than papers using the technique have been published. Most of the papers find the technique valuable for evaluation of nasal patency. Fortunately, some critical papers have drawn attention to some practical aspects of the technique. Standard operating procedures, and calibration checks as well as training operators will enhance the accuracy and reproducibility of results. A decade after its introduction acoustic rhinometry is a well-established method for evaluation of nasal patency, but further improvement can be obtained by continued validation and adjustments of the technique.

Two-dimensional mesh-based mosaic representation for manipulation of video objects with occlusion

We present a two-dimensional (2-D) mesh-based mosaic representation, consisting of an object mesh and a mosaic mesh for each frame and a final mosaic image, for video objects with mildly deformable motion in the presence of self and/or object-to-object (external) occlusion. Unlike classical mosaic representations where successive frames are registered using global motion models, we map the uncovered regions in the successive frames onto the mosaic reference frame using local affine models, i.e., those of the neighboring mesh patches. The proposed method to compute this mosaic representation is tightly coupled with an occlusion adaptive 2-D mesh tracking procedure, which consist of propagating the object mesh frame to frame, and updating of both object and mosaic meshes to optimize texture mapping from the mosaic to each instance of the object. The proposed representation has been applied to video object rendering and editing, including self transfiguration, synthetic transfiguration, and 2-D augmented reality in the presence of self and/or external occlusion. We also provide an algorithm to determine the minimum number of still views needed to reconstruct a replacement mosaic which is needed for synthetic transfiguration. Experimental results are provided to demonstrate both the 2-D mesh-based mosaic synthesis and two different video object editing applications on real video sequences.