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At least 811 records · Page 45Linked to original sources
PubMed2006

An alternative fixation technique for the endoscopic brow lift.

BACKGROUND: Endoscopic brow lift has become widely accepted as a procedure for restoring a youthful brow, since only 3 hardly noticeable incisions of the scalp are needed for this subperiosteal dissection and final repositioning of the brow. It has become an acceptable technique, an alternative to the conventional technique or transcoronal browpexy. One of the controversial points is the fixation of the flap in the elevated position. METHOD: Endoscopic brow lift allows separation and repositioning of the periosteum of the orbital rims and zygomaxilla. In a 6-year period from September 1999, 300 patients underwent endoscopic brow lift using our fixation approach, which was accomplished with an absorbable suture subperiosteally. RESULTS: Satisfactory forehead rejuvenation was obtained in all patients, with correct eyebrow movement. CONCLUSIONS: Long-term results of 6 years confirm the strength and durability of this fixation approach. We consider this approach to be a simple, secure, and reliable forehead fixation method, an alternative to other fixation methods, that allows satisfactory and long-lasting cosmetic results.

Blepharoptosis↗
PubMed2006

High lift function of the pteroid bone and forewing of pterosaurs.

The pteroid bone is a rod-like element found only in pterosaurs, the flying reptiles of the Mesozoic. It articulated at the wrist, and supported a membranous forewing in front of the inner part of the wing spar. The function of this bone, particularly its orientation, has been much debated. It is widely believed that it pointed towards the body, and that the forewing was relatively narrow. An alternative hypothesis states that it was directed forwards during flight, resulting in a much broader forewing that acted as a leading edge flap. We tested scale models in a wind tunnel to determine the aerodynamic consequences of these conflicting hypotheses, and found that performance is greatly improved if the pteroid is directed forwards: the lift: drag ratios are superior and the maximum lift is exceptionally high in comparison with conventional aerofoils. This high lift capability may have enabled even the largest pterosaurs to take off and land without difficulty.

Animals↗
PubMed2004

Design of signal-adapted multidimensional lifting scheme for lossy coding.

This paper proposes a new method for the design of lifting filters to compute a multidimensional nonseparable wavelet transform. Our approach is stated in the general case, and is illustrated for the 2-D separable and for the quincunx images. Results are shown for the JPEG2000 database and for satellite images acquired on a quincunx sampling grid. The design of efficient quincunx filters is a difficult challenge which has already been addressed for specific cases. Our approach enables the design of less expensive filters adapted to the signal statistics to enhance the compression efficiency in a more general case. It is based on a two-step lifting scheme and joins the lifting theory with Wiener's optimization. The prediction step is designed in order to minimize the variance of the signal, and the update step is designed in order to minimize a reconstruction error. Application for lossy compression shows the performances of the method.

Algorithms↗
PubMed2006

A 2-D orientation-adaptive prediction filter in lifting structures for image coding.

Lifting-style implementations of wavelets are widely used in image coders. A two-dimensional (2-D) edge adaptive lifting structure, which is similar to Daubechies 5/3 wavelet, is presented. The 2-D prediction filter predicts the value of the next polyphase component according to an edge orientation estimator of the image. Consequently, the prediction domain is allowed to rotate +/-45 degrees in regions with diagonal gradient. The gradient estimator is computationally inexpensive with additional costs of only six subtractions per lifting instruction, and no multiplications are required.

Algorithms↗
PubMed2006

Light field compression using disparity-compensated lifting and shape adaptation.

We propose disparity-compensated lifting for wavelet compression of light fields. With this approach, we obtain the benefits of wavelet coding, such as scalability in all dimensions, as well as superior compression performance. Additionally, the proposed approach solves the irreversibility limitations of previous light field wavelet coding approaches, using the lifting structure. Our scheme incorporates disparity compensation into the lifting structure for the transform across the views in the light field data set. Another transform is performed to exploit the coherence among neighboring pixels, followed by a modified SPIHT coder and rate-distortion optimized bitstream assembly. A view-sequencing algorithm is developed to organize the views for encoding. For light fields of an object, we propose to use shape adaptation to improve the compression efficiency and visual quality of the images. The necessary shape information is efficiently coded based on prediction from the existing geometry model. Experimental results show that the proposed scheme exhibits superior compression performance over existing light field compression techniques.

Algorithms↗
PubMed2006

A comparison of an anterior jaw lift manoeuvre with the Berman airway for assisting fibreoptic orotracheal intubation.

This study compared the efficacy of an anterior jaw lift manoeuvre with that of the Berman airway in clearing the upper airway during oral fibreoptic tracheal intubation in anaesthetised, paralysed patients. Fifty patients were randomly assigned to undergo fibreoptic-assisted intubation with one method, followed by crossover to the alternative method. The time taken to view the vocal cords was the primary endpoint, and we also noted the rate of failure to view the cords, i.e. cords not seen after 120 s of endoscopy. Anterior jaw lift yielded significantly shorter times to view the vocal cords (median [interquartile range; range]: 22 [17-46; 7-120] s vs 40 [29-67; 21-120] s, p = 0.001) and a higher success rate (49/50 vs 42/50, p = 0.014). We conclude that the anterior jaw lift is more effective than the Berman device for achieving airway clearance in this setting.

Adolescent↗
PubMed1992

Extensive scalp lifting as a reconstructive tool for a large scalp defect.

Extensive scalp lifting is a relatively new technique for the treatment of alopecia. Because this technique involves the undermining of the entire occipitoparietal scalp down to the hairline of the nape, a significant anterior and medial advancement is accomplished with one operation. This case report describes a patient with a large surgically induced scalp defect that was reconstructed with the use of extensive scalp lifting in combination with coronal brow lifting--thus, the intermediate cosmetic deformity of the more commonly used tissue expansion technique was completely circumvented. Why this technique can be substituted for tissue expansion or multiple rotation-transposition flaps in certain cases in elaborated.

Alopecia↗
PubMed1990

Accuracy of weight estimation for weights lifted by proximal and distal muscles of the human upper limb.

1. It is well established that tactile acuity is greater over digits than over the proximal parts of the upper limb and that the corticospinal projection is especially dense for distal muscles. To determine whether the acuity for judgements of forces exerted by distal muscles differed from that for proximal muscles, a weight-matching task was used with first dorsal interosseous, flexor pollicus longus and elbow flexors. 2. Reference weights equivalent to approximately 3% (light) and 15% (heavy) of the maximal voluntary contraction were lifted by one muscle group on the left. They were matched with a variable weight, lifted by the same group, on the right. 3. In naive subjects, the coefficient of variation for repeated estimates of perceived heaviness was significantly lower for proximal than distal muscles. Measured in this way, 'accuracy' (i.e. reproducibility of the estimates) was not greater for the intrinsic muscles of the hand. This result could not be explained by the way in which the weights were supported by the index finger. When the data were expressed as the relative difference between the reference and the matched weight, each muscle group behaved similarly. 4. For a particular muscle, accuracy was greater when the heavy rather than the light weights were lifted. 5. Given that estimates of forces and heaviness are biased by signals of central motor command (McCloskey, 1981; Gandevia, 1987; Cafarelli, 1988; Jones, 1988). these signals could be graded no more finely for distal than proximal muscles. Furthermore, relative accuracy was greater for forces at the high rather than the low end of the comfortable 'matching' range of force for a particular muscle.

Adult↗
PubMed1999

Finite element analysis of the lift on a slightly deformable and freely rotating and translating cylinder in two-dimensional channel flow.

Motivated by the lateral migration phenomena of fresh and glutaraldehyde-fixed red blood cells in a field flow fractionation (FFF) separation system, we studied the transverse hydrodynamic lift on a slightly flexible cylinder in a two-dimensional channel flow. The finite element method was used to analyze the flow field with the cylinder at different transverse locations in the channel. The shape of the cylinder was determined by the pressure on the surface of the cylinder from the flow field solution and by the internal elastic stress. The cylinder deformation and the flow field were solved simultaneously. The transverse lift exerted on the cylinder was then calculated. The axial and angular speed of the cylinder were iterated such that the drag and torque on the cylinder were nulled to represent a freely translating and rotating state. The results showed that the transverse lift on a deformable cylinder increased greatly and the equilibrium position moved closer to the center of the channel compared to a rigid cylinder. Also, with the same elastic modulus but a higher flow rate, a larger deformation and higher equilibrium location were found. The maximum deformation of the cylinder occurred when the cylinder was closest to the wall where a larger shear rate existed. The numerical results and experimental studies are discussed.

Blood Flow Velocity↗
PubMed2007

Sinus lifting before Le Fort I maxillary osteotomy: a suitable method for oral rehabilitation of edentulous patients with skeletal class-III conditions: review of the literature and report of a case.

BACKGROUND: Functional rehabilitation of patients afflicted with severe mandibular and maxillary alveolar atrophy might be challenging especially in malformed patients. METHODS: Treatment planning using sinus lifting and implant placement before Le Fort I maxillary osteotomy in a patient with severe mandibular and posterior maxillary alveolar atrophy and skeletal class-III conditions due to cleft palate are described. RESULTS: A full functional and esthetic rehabilitation of the patient was achieved by a stepwise surgical approach performed through sinus lifting as the primary approach followed by implant placement and subsequent Le Fort I maxillary osteotomy to correct the maxillo-mandibular relation. CONCLUSION: Stabilisation of the maxillary complex by a sinus lifting procedure in combination with computer aided implant placement as preorthodontic planning procedure before Le Fort I maxillary osteotomy seems to be suitable in order to allow ideal oral rehabilitation especially in malformed patients.

Alveolar Bone Loss↗
PubMed2004

The effects of chin lift and jaw thrust while in the lateral position on stridor score in anesthetized children with adenotonsillar hypertrophy.

Obstruction of the upper airway is a major challenge for anesthesiologists administering general anesthesia in spontaneously breathing patients, especially in pediatric anesthesia with adenotonsillar hypertrophy. Lateral positioning is a simple treatment for obstructive sleep apnea and also decreases collapsibility of the pharynx in anesthetized adults with obstructive sleep apnea. In this study, we examined the effects of body position shifting and common airway maneuvers, such as chin lift and jaw thrust, on airway patency (stridor score) in anesthetized children scheduled for adenotonsillectomy. Thirty children aged 1-10 yr were anesthetized with sevoflurane. During spontaneous breathing of 5% sevoflurane, stridor score was recorded. After baseline recording, chin lift and jaw thrust were performed on patients in both the supine and the lateral decubitus positions. Chin lift and jaw thrust improved the stridor score. Furthermore, lateral positioning dramatically enhanced the effects of these airway maneuvers on airway patency. Jaw thrust combined with lateral positioning provided easy airway management for the anesthesiologists. We conclude that lateral positioning combined with airway maneuvers significantly improved airway patency compared with the airway maneuvers alone for patients in the supine position.

Adenoidectomy↗
PubMed1997

Dragonfly flight. III. Lift and power requirements.

A mean lift coefficient quasi-steady analysis has been applied to the free flight of the dragonfly Sympetrum sanguineum and the damselfly Calopteryx splendens. The analysis accommodated the yaw and accelerations involved in free flight. For any given velocity or resultant aerodynamic force (thrust), the damselfly mean lift coefficient was higher than that for the dragonfly because of its clap and fling. For both species, the maximum mean lift coefficient L was higher than the steady CL,max. Both species aligned their strokes planes to be nearly normal to the thrust, a strategy that reduces the L required for flight and which is different from the previously published hovering and slow dragonfly flights with stroke planes steeply inclined to the horizontal. Owing to the relatively low costs of accelerating the wing, the aerodynamic power required for flight represents the mechanical power output from the muscles. The maximum muscle mass-specific power was estimated at 156 and 166 W kg-1 for S. sanguineum and C. splendens, respectively. Measurements of heat production immediately after flight resulted in mechanical efficiency estimates of 13 % and 9 % for S. sanguineum and C. splendens muscles, respectively.

Journal Article↗
PubMed2001

Effects of stretch receptor ablation on the optomotor control of lift in the hawkmoth Manduca sexta.

In insects, fast sensory feedback from specialized mechanoreceptors is integrated with guidance cues descending from the visual system to control flight behavior. A proprioceptive sensory organ found in both locusts and moths, the wing hinge stretch receptor, has been extensively studied in locusts for its powerful influence on the activity of flight muscle motoneurons and interneurons. The stretch receptor fires a high-frequency burst of action potentials near the top of each wingstroke and encodes kinematic variables such as amplitude and timing. Here, I describe the effects of stretch receptor ablation on the visual control of lift during flight in the hawkmoth Manduca sexta. Using a combination of extracellular muscle recordings, force and position measurements and high-speed video recording, I tracked power muscle activity, net vertical flight force (lift), abdomen deflection and wing kinematics in response to image motions of varying velocity during tethered flight in a wind tunnel. As a result of bilateral ablation of the wing hinge stretch receptors, visually evoked lift decreased to nearly one-third of that exhibited by intact animals. The phase and frequency of indirect power muscle action potentials and the patterns of abdominal deflection were unaffected; however, wingstroke amplitude was clearly reduced after ablation. Collectively, these results suggest that stretch receptor feedback is integrated with descending visual cues to control wing kinematics and the resultant aerodynamic force production during flight.

Animals↗
PubMed1996

An isometric predictor for maximum acceptable weight of lift for Chinese men.

The aim of this study was to examine the practicality of the modified isometric strength tests to predict the maximum acceptable weight of lift (MAWL) of Chinese men. The modified strength tests allow the participant to pull on the load cell in front of the body and to apply force in a functional free posture. Both the modified and the standard strength data of each participant were used as predictors for the MAWLs. The prediction models were constructed and evaluated under task conditions of two lifting ranges, two box sizes, and three lifting frequencies. To realize the effect of modifications, testing posture was recorded and the joint angles were calculated. A stepwise multiple regression analysis indicated that modified composite strength (MCS), chest circumference, and acromial height accounted for 86% to 91% of the variance. Because the strength of the upper extremity body was also recruited in the test, the weak upper extremity strength of the Chinese participants would therefore be better reflected. Evidence for the existence of a close match between MAWL and MCS values, as well as the task conditions for its existence, suggest that a simple isometric strength measure is a good predictor for the MAWL.

Adult↗
PubMed1995

Do palatal lift prostheses stimulate velopharyngeal neuromuscular activity?

The purpose of this investigation was to evaluate the ability of palatal lift prostheses to stimulate the neuromuscular activity of the velopharynx. Nasendoscopic evaluations were audio-videotaped preprosthetic and postprosthetic management for 25 patients who underwent placement of a palatal lift prosthesis for velopharyngeal dysfunction (VPD). These audio-videotapes were presented in blinded fashion and random order to three speech pathologists experienced in assessment of patients with VPD. They rated the tapes on the following parameters: VP gap size, closure pattern, orifice estimate, direction and magnitude of change, and qualitative descriptions of the adequacy of VP closure during speech. VP closure for speech was unchanged in 69% of patients and the number of patients rated as improved or deteriorated was nearly identical at about 15%. Postintervention gap shape remained unchanged in 70% of patients. The extent of VP orifice closure during speech remained unchanged in 57% of patients. Articulations that could impair VP function improved in 30% of patients, deteriorating in only 4%. Results of this study neither support the concept that palatal lift prostheses alter the neuromuscular patterning of the velopharynx, nor provide objective documentation of the feasibility of prosthetic reduction for weaning.

Adolescent↗
PubMed1999

Periodontal and computer tomography scanning evaluation of endosseous implants in conjunction with sinus lift procedure. A 6-case series.

The aim of the present study was to evaluate endosseous implants in conjunction with the sinus lift procedure using periodontal parameters and computed tomography (CT) scanning. In 6 patients, 8 sinus lift procedures were performed to the atrophic posterior maxilla. Fourteen endosseous implants were placed. The condition of the peri-implant mucosa was assessed postoperatively at an average of 31 months using periodontal parameters such as plaque index, probing depth, clinical attachment level, and bleeding on probing. All the implants were maintained in a clinically healthy condition throughout the observation period. CT images revealed the difference in the morphology of the sinus floor between the locations of the block-shaped bone and the small pieces of bone which were both grafted. The results indicated that endosseous implants in conjunction with the sinus lift procedure could be maintained by monitoring the periodontal parameters.

Adult↗
PubMed1999

Radiological findings of the post-sinus lift maxillary sinus: a computerized tomography follow-up.

The purpose of this paper is to present radiological findings of a short-term (8 to 10 months) computerized tomography (CT) follow-up study on 1-stage maxillary sinus lift cases. Pre- and postoperative dental CT scans of 21 patients (24 sinuses) after sinus lift procedures were compared. CT scans were used to assess newly formed bone and its interface with the implants, condition of the sinus membrane, evidence of buccal window cortication, and presence of any sinus pathology. Of the 57 implants placed, 28 had bone fully covering the implant on all sides which did not extend above the apical portion; 20 had bone fully covering the implant which did extend above the apex; and 9 exhibited incomplete bone coverage. All implants supported a fixed ceramo-metal prosthesis, and no implant failures were recorded after 3 years of follow-up. There was evidence of cortication of the buccal window in 10 sinuses; in the 14 remaining sinuses, bone consolidation on the buccal aspect was evident, but no evidence of cortication was seen. All sinuses healed without complications or clinical signs of sinusitis. In 11 sinuses, no changes in membrane thickness were noted. Membrane thickness decreased postoperatively in 12 sinuses, and in one, there was evidence of membrane thickening. Bone cortication in the anterior wall window may serve as an indicator for the remodeling status of the entire graft. Postoperative findings showed a significant improvement in overall membrane thickness. No clinical symptoms of sinusitis were evident, indicating that sinus lift procedures can be considered safe and do not predispose the sinus to acute or chronic sinusitis.

Adult↗
PubMed1997

A comparison of trunk extensor strength and squat lifting ability.

Back testing devices are frequently utilized in the clinic to assess function and return to work readiness in place of the job task, yet little research on their validity has been reported. This study was conducted to determine if correlations exist between squat lifting and isoinertial and isometric trunk extensor strength, torso length and isoinertial and isometric trunk extensor strength, and body weight and isoinertial and isometric trunk extensor strength. Twenty-eight subjects participated in two sessions involving B200 testing and 30.5 cm to knuckle lifting ability. Regression and correlations were performed. The results indicate that body weight and torso length do not demonstrate a relationship with trunk extensor strength, and isometric and isoinertial trunk extensor strength cannot be used accurately to estimate one's 30.5 cm to knuckle lifting ability. In conclusion, other anthropometric measures should be investigated if anthropometrics are used to estimate strength, and functional testing should be used to evaluate function.

Adult↗