Characterising the physical demands of critical tasks across the Royal Australian Air Force

BACKGROUND

Militaries have historically utilised generic physical fitness tests to assess physical readiness, but there has been a recent shift to develop physical employment standards (PES) based on actual job demands.

OBJECTIVE

The purpose of this investigation was to characterise the physical demands of critical tasks performed by Royal Australian Air Force (RAAF) personnel to inform PES development.

METHODS

Job task analysis were performed for 27 RAAF trades. Criterion tasks were identified through a systematic approach involving workshops and field-observations. The identified tasks were assessed for dominant physical capacity and grouped into movement-based clusters. Psychophysiological measures were collected from personnel performing the tasks.

RESULTS

Of 87 criterion tasks, 92% were characterised as manual handling dominant. Across these 87 tasks the principal physical capacities were: muscular strength (59%), muscular endurance (52%) and cardiorespiratory endurance (39%). The most common movement clusters were Lift to Platform (44%) and Lift and Carry (38%). Lift to Platform tasks required lifting to a median height of 1.32 m (1.20 -1.65 m) and a median mass of 25.0 kg (21.0 -28.9 kg) per person. Median carry mass was 25.0 kg (22.4 -36.1 kg) per person and distance was 26.0 m (17.5 -50.0 m). Median task mean 'Vdot;O2, HR and RPE were 1.8 L.min- 1 (1.5-2.2 L.min- 1), 137 b.min- 1 (120-144) and 13 (12-14).

CONCLUSIONS

The high proportion of manual handling criterion tasks emphasises the importance of these activities and the underlying physical capacities for RAAF personnel. Current fitness assessments are unlikely to predict job task performance.

The Lift Effects of Chordwise Wing Deformation and Body Angle on Low-Speed Flying Butterflies

This work investigates the effects of body angle and wing deformation on the lift of free-flying butterflies. The flight kinematics were recorded using three high-speed cameras, and particle-image velocimetry (PIV) was used to analyze the transient flow field around the butterfly. Parametric studies via numerical simulations were also conducted to examine the force generation of the wing by fixing different body angles and amplifying the chordwise deformation. The results show that appropriately amplifying chordwise deformation enhances wing performance due to an increase in the strength of the vortex and a more stabilized attached vortex. The wing undergoes a significant chordwise deformation, which can generate a larger lift coefficient than that with a higher body angle, resulting in a 14% increase compared to a lower chordwise deformation and body angle. This effect is due to the leading-edge vortex attached to the curved wing, which alters the force from horizontal to vertical. It, therefore, produces more efficient lift during flight. These findings reveal that the chordwise deformation of the wing and the body angle could increase the lift of the butterfly. This work was inspired by real butterfly flight, and the results could provide valuable knowledge about lift generation for designing microaerial vehicles.

A Procedure for Taking a Remotely Controlled Elevator with an Autonomous Mobile Robot Based on 2D LIDAR

Navigating between the different floors of a multistory building is a task that requires walking up or down stairs or taking an elevator or lift. This work proposes a procedure to take a remotely controlled elevator with an autonomous mobile robot based on 2D LIDAR. The application of the procedure requires ICP matching for mobile robot self-localization, a building with remotely controlled elevators, and a 2D map of the floors of the building detailing the position of the elevators. The results show that the application of the procedure enables an autonomous mobile robot to take a remotely controlled elevator and to navigate between floors based on 2D LIDAR information.

An Exploration of the Influence of Non-Biomechanical Factors on Lifting-Related LBP

Objective: The primary objective was to compare non-biomechanical factors between manual workers with and without a history of LBP related to lifting. A secondary objective was to investigate associations between the change in pain intensity during repeated lifting (termed pain ramp) and non-biomechanical factors tested in the LBP group. Methods: Manual workers currently in lifting occupations with and without a history of lifting-related LBP were recruited (21 LBP and 20 noLBP) and took part in a repeated (100) lift task. A series of non-biomechanical factors, including psychological, work-related, lifestyle, whole health and psychophysical factors, were collected. Psychophysical factors (pressure pain thresholds (PPTs) and fatigue) were also measured at different time points. Associations between pain ramp during lifting and non-biomechanical factors were investigated with linear regression. Results: The LBP group reported worse perceived sleep quality, more musculoskeletal pain sites other than LBP and greater symptoms related to gastrointestinal complaints and pseudo-neurology compared to the group with no history of LBP. The group with LBP were also slightly more worried about the lifting task and felt more fatigued at the end of the lifting task. The feeling of fatigue during lifting was positively associated with pain ramp in the LBP group. Anxiety and gastrointestinal complaints were weakly negatively associated with pain ramp during lifting. Conclusions: The group differences of poorer perceived sleep, greater non-specific health complaints, slightly more worry about the lifting task and more perceived fatigue in the LBP group highlight the complex and multi-factorial nature of LBP related to lifting. The feeling of fatigue was positively associated with pain ramp in the LBP group, suggesting a close relationship with pain and fatigue during lifting that requires further exploration.

Numerical study of transient aerodynamic forces acting on a ski jumper considering dynamic posture change from takeoff to landing

This study was designed to develop a computational fluid dynamics (CFD) method for unsteady analysis of a series of ski jump movements with attitude changes, and to analyse the aerodynamic characteristics of an expert jumper over the entire ski jump movement. Two ski jumpers participated in this study. A sensor-based motion capture suit was used to capture the jumper's posture during the actual ski jump. A three-dimensional computer graphics animation was created by superimposing the joint angles obtained from the motion measurements of the 3D shape of the athlete. The unsteady aerodynamic forces acting on the ski jumper, from the takeoff to the landing, were then calculated using CFD. A time-varying spatially uniform flow was specified as the inflow boundary condition of the computational domain. The results indicated that both the lift and drag forces of the expert jumper increase rapidly during the initial flight when the jumper's posture changes drastically. Thereafter, drag force decreased considerably, but the decrease in the lift force was less drastic. Later in the flight phase, the lift force acting on the expert jumper increased, and throughout the flight phase, the lift-drag ratio of the expert jumper remained higher than that of the unskilled jumper.

The effect of forearm position on elbow flexion strength in nursing, occupational, and physical therapy students

BACKGROUND

Novice nurses, occupational and physical therapist's injury rates are alarming.

OBJECTIVE

To test for differences in peak elbow flexion forces (PEFF) by profession using different forearm positions.

METHODS

Entry-level RN, OT, and PT students performed 3-repetitions of standing PEFF in forearm supination, pronation, and neutral. A one-way repeated measures ANOVA determined the forearm position with the greatest PEFF. A one-way ANOVA assessed differences in PEFF between professions. The alpha level was set at p≤0.05 for all analyses.

RESULTS

Thirty 30 RN, 25 OT, and 30 PT students (x = 23.27 + /-3.29 yrs.) were studied. A one-way repeated measures ANOVA revealed a significant difference in PEFF between positions (F(2,168) = 144.3, p < 0.0001). A significant (p < 0.0001) pairwise comparison revealed neutral produced the greatest (28.15 + /-12.64 kg) and pronation the least PEFF (17.27 + /-7.40). PEFF was significantly different between position by profession (supination: F(2,82) = 10.14, p < 0.0001; pronation: F(2,82) = 10.33, p < 0.0001; neutral: F(2,82) = 13.39, p < 0.0001). PTs were significantly stronger than OTs and RN students in all forearm positions (p < 0.01).

CONCLUSIONS

Neutral PEFF was greatest and PT students demonstrated greater PEFF than OT and RN students.

Estimating Muscle Forces for Breast Cancer Survivors During Functional Tasks

Breast cancer survivors have known scapular kinematic alterations that may be related to the development of secondary morbidities. A measure of muscle activation would help understand the mechanisms behind potential harmful kinematics. The purpose of this study was to define muscle force strategies in breast cancer survivors. Shoulder muscle forces during 6 functional tasks were predicted for 25 breast cancer survivors (divided by impingement pain) and 25 controls using a modified Shoulder Loading Analysis Module. Maximum forces for each muscle were calculated, and 1-way analysis of variance (P < .05) was used to identify group differences. The differences between maximum predicted forces and maximum electromyography were compared with repeated-measures analysis of variance (P < .05) to evaluate the success of the model predictions. Average differences between force predictions and electromyography ranged from 7.3% to 31.6% but were within the range of previously accepted differences. Impingement related pain in breast cancer survivors is associated with increased force of select shoulder muscles. Both pectoralis major heads, upper trapezius, and supraspinatus peak forces were higher in the pain group across all tasks. These force prediction differences are also associated with potentially harmful kinematic strategies, providing a direction for possible rehabilitation strategies.

A comparison of three shoe sole impression lifting methods at high substrate temperatures

Footwear impressions are a common form of evidence found at crime scenes, and the accurate recovery and recording of such impressions is critical for shoe sole comparison and identification. The lifting of shoe sole impressions from hot surfaces (>30°C/86°F) and in hot environments has received little attention in the literature, particularly in relation to the recovery of class and randomly acquired characteristics (RACs) required for accurate comparisons. This study addressed this knowledge gap by comparing the performance of three common impression lifters (gelatin, adhesive, and vinyl static cling film) at recovering shoe sole impressions in dust from hot flooring substrates. Dry origin dust shoe sole impressions were made on ceramic tile, galvanized metal, and laminated wood flooring using a shoe that possessed two RACs and five class characteristics present on the sole. Substrates were left in direct full sun for five hours during a summer day prior to lifting. Performance was measured by the proportion of RACs and class characteristics visible in each lifted impression. Results demonstrated that the vinyl static cling film tested performed poorly across all substrates, particularly for metal (23.8% marks recovered), including notable shrinkage of the lifted impression. In contrast, adhesive (~96% marks recovered over all substrates), and to a lesser extent gelatin (~85%), lifts were highly successful on hot substrates. These data suggest that adhesive lifts can consistently and accurately recover shoe sole impressions from hot substrates. This study contributes critical information for crime scene examiners to improve and expand evidence recovery in hot environments.

Complex Anal Fistula: Long-Term Results of Modified Ligation of Intersphincteric Fistula Tract=LIFT

Objectives:

The anal fistula is a permanent infectious tunnel formed between the anal canal and skin in the perianal region. Fistulas are treated by surgery at any stage. Many surgical methods have been reported to treat anal fistula. One of the promising surgical methods with a high success rate is ligation of the intersphincteric fistula tract, which is performed in anatomical spaces without damage to the internal and external sphincters. We evaluated the success rate of a modified ligation of the intersphincteric fistula tract procedure for complex anal fistulas in which the technical differences were minimized by the surgery being performed by the same surgical team.

Methods:

In this study, Data of the 56 patients were retrospectively collected. Data regarding patient history, visual and digital anal examination, Cleveland Clinic Florida Fecal Incontinence (CCF-FI) score, anal-phase pelvic magnetic resonance imaging (MRI), rectosigmoidoscopy or colonoscopy and anal manometry were recorded. The changes in data recorded during the preoperative and postoperative periods were compared in each other.

Results:

The mean age of the patients was 41±15.5 years. The number of patients for each fistula type compromised in this study was as follows in accordance with frequency: high transsphincteric fistula, high intersphincteric fistula, and horseshoe abscess. The fistula recurred in seven patients during postoperative follow-up and the success rate of modified LIFT was calculated as 87.5%. The change in the mean±SD preoperative and postoperative CCF-FI scores and anal pressure was not statistically significant.

Conclusion:

One promising advantage of the ligation of the intersphincteric fistula tract procedure is that it turns a complex fistula into a simple fistula that can be treated with minimal risk of sphincter damage.

Characterizing Human Box-Lifting Behavior Using Wearable Inertial Motion Sensors

Although several studies have used wearable sensors to analyze human lifting, this has generally only been done in a limited manner. In this proof-of-concept study, we investigate multiple aspects of offline lift characterization using wearable inertial measurement sensors: detecting the start and end of the lift and classifying the vertical movement of the object, the posture used, the weight of the object, and the asymmetry involved. In addition, the lift duration, horizontal distance from the lifter to the object, the vertical displacement of the object, and the asymmetric angle are computed as lift parameters. Twenty-four healthy participants performed two repetitions of 30 different main lifts each while wearing a commercial inertial measurement system. The data from these trials were used to develop, train, and evaluate the lift characterization algorithms presented. The lift detection algorithm had a start time error of 0.10 s ± 0.21 s and an end time error of 0.36 s ± 0.27 s across all 1489 lift trials with no missed lifts. For posture, asymmetry, vertical movement, and weight, our classifiers achieved accuracies of 96.8%, 98.3%, 97.3%, and 64.2%, respectively, for automatically detected lifts. The vertical height and displacement estimates were, on average, within 25 cm of the reference values. The horizontal distances measured for some lifts were quite different than expected (up to 14.5 cm), but were very consistent. Estimated asymmetry angles were similarly precise. In the future, these proof-of-concept offline algorithms can be expanded and improved to work in real-time. This would enable their use in applications such as real-time health monitoring and feedback for assistive devices.

Stimulation of collagenesis by poly-L-lactic acid (PLLA) and -glycolide polymer (PLGA)-containing absorbable suspension suture and parallel sustained clinical benefit

BACKGROUND

Though the collagen-stimulating capacity of poly-L-lactic acid (PLLA) is well established, no data are available on collagen stimulation by the PLLA/PLGA within absorbable suspension sutures used for tissue repositioning.

AIMS

To characterize collagen stimulation by absorbable suspension sutures through examination of patient biopsies and assess severity of nasolabial folds (NLF) over time.

PATIENTS/METHODS

Single-center, open-label, prospective study of 25 healthy volunteers treated with absorbable suspension sutures for descent of midface tissues. Punch biopsies were collected and evaluated for total collagen content. Subject and investigators evaluated NLF severity using the Nasolabial Fold Wrinkle Assessment Score (NLF-WAS). Seventeen of 25 patients completed the collagenesis portion of the study.

RESULTS

Collagen deposition was apparent at day 90 and increased significantly compared with baseline at days 180 and 270 and between days 90 and 180. Subject- and investigator-reported NLF-WAS were significantly improved at all post-treatment time points through day 270.

CONCLUSIONS

Absorbable suspension sutures stimulate collagen in areas immediately adjacent to the path of the PLLA/PLGA monofilament and cones, providing mechanistic support for improvement in appearance observed in clinical studies. This neocollagenesis, coupled with repositioning by the suture's cones, makes absorbable suspension sutures a valuable tool for patients seeking facial rejuvenation.

To Flex or Not to Flex? Is There a Relationship Between Lumbar Spine Flexion During Lifting and Low Back Pain? A Systematic Review With Meta-analysis

OBJECTIVE

To evaluate whether lumbar spine flexion during lifting is a risk factor for low back pain (LBP) onset/persistence or a differentiator of people with and without LBP.

DESIGN

Etiology systematic review with meta-analysis.

LITERATURE SEARCH

Database search of ProQuest, CINAHL, MEDLINE, and Embase up to August 21, 2018.

STUDY SELECTION CRITERIA

We included peer-reviewed articles that investigated whether lumbar spine position during lifting was a risk factor for LBP onset or persistence or a differentiator of people with and without LBP.

DATA SYNTHESIS

Lifting-task comparison data were tabulated and summarized. The meta-analysis calculated an n-weighted pooled mean ± SD of the results in the LBP and no-LBP groups. If a study contained multiple comparisons (ie, different lifting tasks that used various weights or directions), then only 1 result from that study was included in the meta-analysis.

RESULTS

Four studies (1 longitudinal study and 3 cross-sectional studies across 5 articles) included in meta-analysis measured lumbar flexion with intralumbar angles and found no difference in peak lumbar spine flexion when lifting (1.5°; 95% confidence interval [CI]: -0.7°, 3.7°; P = .19 for the longitudinal study and -0.9°; 95% CI: -2.5°, 0.7°; P = .29 for the cross-sectional studies). Seven cross-sectional studies measured lumbar flexion with thoracopelvic angles and found that people with LBP lifted with 6.0° less lumbar flexion than people without LBP (95% CI: -11.2°, -0.9°; P = .02). Most (9/11) studies reported no significant between-group differences in lumbar flexion during lifting. The included studies were of low quality.

CONCLUSION

There was low-quality evidence that greater lumbar spine flexion during lifting was not a risk factor for LBP onset/persistence or a differentiator of people with and without LBP. J Orthop Sports Phys Ther 2020;50(3):121-130. Epub 28 Nov 2019. doi:10.2519/jospt.2020.9218.

Comparison of text processing methods in social media-based signal detection

PURPOSE

Adverse event (AE) identification in social media (SM) can be performed using various types of natural language processing (NLP) and machine learning (ML). These methods can be categorized by complexity and precision level. Co-occurrence-based ML methods are rather basic, as they identify simultaneous appearance of drugs and clinical events in a single post. In contrast, statistical learning methods involve more complex NLP and identify drugs, events, and associations between them. We aimed to compare the ability of co-occurrence and NLP to identify AEs and signals of disproportionate reporting (SDR) in patient-generated SM. We also examined the performance of lift in SM-based signal detection (SD).

METHODS

Our examination was performed in a corpus of SM posts crawled from open online patient forums and communities, using the spontaneously reported VigiBase data as reference data set.

RESULTS

We found that co-occurrence and NLP produce AEs, which are 57% and 93% consistent with VigiBase AEs, respectively. Among the SDRs identified both in SM and in VigiBase, up to 55.3% were identified earlier in co-occurrence, and up to 32.1% were identified earlier in NLP-processed SM. Using lift in SM SD provided performance similar to frequentist methods, both in co-occurrence and in NLP-processed AEs.

CONCLUSION

Our results indicate that using SM as a data source complementary to traditional pharmacovigilance sources should be considered further. Various levels of SM processing may be considered, depending on the preferred policies and tolerance for false-positive to false-negative balance in routine pharmacovigilance processes.

Shark skin-inspired designs that improve aerodynamic performance

There have been significant efforts recently aimed at improving the aerodynamic performance of aerofoils through the modification of their surfaces. Inspired by the drag-reducing properties of the tooth-like denticles that cover the skin of sharks, we describe here experimental and simulation-based investigations into the aerodynamic effects of novel denticle-inspired designs placed along the suction side of an aerofoil. Through parametric modelling to query a wide range of different designs, we discovered a set of denticle-inspired surface structures that achieve simultaneous drag reduction and lift generation on an aerofoil, resulting in lift-to-drag ratio improvements comparable to the best-reported for traditional low-profile vortex generators and even outperforming these existing designs at low angles of attack with improvements of up to 323%. Such behaviour is enabled by two concurrent mechanisms: (i) a separation bubble in the denticle's wake altering the flow pressure distribution of the aerofoil to enhance suction and (ii) streamwise vortices that replenish momentum loss in the boundary layer due to skin friction. Our findings not only open new avenues for improved aerodynamic design, but also provide new perspective on the role of the complex and potentially multifunctional morphology of shark denticles for increased swimming efficiency.

Superb autorotator: rapid decelerations in impulsively launched samaras

Autorotation of botanical samaras, with a consequent reduction in their rate of descent, increases dispersal range in the presence of horizontal winds. Samaras in initial free fall from rest pass through a brief transitional phase prior to reaching their minimum rate of descent and stable autorotation. By contrast, intense wind gusts and elastic recoil of tree branches can produce impulsive samara detachment and accelerate them rapidly through the air. Here, we investigate the autorotation of maple samaras when launched with a high initial impulse. Norway maple seeds catapulted either vertically or horizontally at approximately 9 m s^-1 exhibited remarkably high and rapid decelerations (10-15 g) and reached a near-zero translational speed in less than 150 ms. The initial rotational frequency of catapulted seeds was up to four times greater than that ultimately reached during steady-state autorotation. These helicopter seeds thus transiently produce very high lift forces (at Reynolds numbers near approximately 10⁴) that act to enhance aerial transport. These findings are relevant to the modelling of long-distance seed dispersal in unsteady flows, as well as to the design of deceleration mechanisms based on lift generation, rather than drag-based devices such as parachutes.

Protocol for a multicentre randomised controlled parallel-group trial to compare the effectiveness of remotely delivered cognitive-behavioural and graded exercise interventions with usual care alone to lessen the impact of fatigue in inflammatory rheumatic diseases (LIFT)

INTRODUCTION

Fatigue remains pervasive, disabling and challenging to manage across all inflammatory rheumatic diseases (IRDs). Non-pharmacological interventions, specifically cognitive-behavioural approaches (CBAs) and graded exercise programmes designed to support and increase exercise, are valuable treatments which help patients with IRD to manage their fatigue. Yet, healthcare systems have encountered substantial barriers to the implementation of these therapeutic options. Lessening the Impact of Fatigue in Inflammatory Rheumatic Diseases: a Randomised Trial (LIFT) is designed to give insights into the effectiveness of a remotely delivered standardised intervention for a range of patients with IRD. It will also enable the exploration of putative moderating factors which may allow for the future triage of patients and to investigate the precise mediators of treatment effect in IRD-related fatigue.

METHODS AND ANALYSIS

LIFT is a pragmatic, multicentre, three-arm randomised, controlled trial, which will test whether adapted CBA and personalised exercise programme interventions can individually reduce the impact and severity of fatigue. This will be conducted with up to 375 eligible patients diagnosed with IRD and interventions will be delivered by rheumatology healthcare professionals, using the telephone or internet-based audio/video calls.

ETHICS APPROVAL AND DISSEMINATION

Ethical approval has been granted by Wales REC 7 (17/WA/0065). Results of this study will be disseminated through presentation at scientific conferences and in scientific journal. A lay summary of the results will be sent to participants.

TRIAL REGISTRATION NUMBER

NCT03248518; Pre-results.

Slipstreaming in Gravity Powered Sports: Application to Racing Strategy in Ski Cross

The principles of slipstreaming or drafting are very well known in muscle-powered sports, but unknown in gravity-powered sports. Typical examples of gravity-powered sports, where several athletes are racing against each other, are ski-cross and snowboard-cross. The aim of this research is to investigate the effectiveness and practical applicability of slipstreaming in ski-cross. A glide model consisting of leading and trailing skiers was developed and used with existing aerodynamic drag and lift data sets from wind tunnel tests. Different scenarios were tested as to their effect on slipstreaming, such as variation of speed, skiers' mass, slope angle, air density, and racing posture (high/low tucked position). The higher the trailing skier's inertial force and acceleration is compared to the leading one, the quicker the trailing skier can catch up. Making more ground up on the racing track is related to higher speed, less body mass (of both skiers), flatter slope angle, denser air, and higher racing posture (high tucked position of both skiers). The glide model presented in this research can be used in the future for testing of slope track design, provided that precise dimensions of terrain features are available.

Acquisition of a Digital Intraoral Scanning Device: An Examination of Practice Volume Changes and the Economic Impact via an Interrupted Time Series Analysis

OBJECTIVES

To evaluate the impact of digital scanning in general dental practices and orthodontic practices to determine the percentage of lift, i.e., the percent increase in gross receipts, of Invisalign® treatment starts following the introduction of an iTero® intraoral scanner.

METHODS

An interrupted time series analysis was conducted on 48 months (24 pre- and 24 post-scanner introduction) of Invisalign receipt data from 1,871 general practitioner (GP) and orthodontic practices located worldwide. Analyses also explored the presence of a longer shift in the trend of monthly Invisalign receipts after scanner introduction (i.e., pre-post slope change), and projected the impact of the introduction of the scanner within a specific subset of practices (n = 319) that represented North American GPs with low initial practice volumes (i.e., 5 or fewer receipts in the 12 months prior to acquiring the scanner).

RESULTS

For the entire sample, introduction of the iTero intraoral scanner at month 25 showed a significant and abrupt increase in receipts for Invisalign therapy (b = 0.49; p < 0.001). When compared to the counterfactual regression line prediction without the scanner, in month 25 Invisalign practice receipts increased from the predicted value of 2.38 to 2.88, an increase of 20.71%. When the analysis was conducted using only low-volume GP practices in North America, the introduction of the scanner at month 25 also led to a significant and abrupt increase in practice receipts (b = 0.28; p < 0.001), and this increase was still evident 24 months after scanner introduction.

CONCLUSIONS

The results show that acquiring an iTero intraoral scanner as a precursor to Invisalign therapy is associated with a significant increase in Invisalign practice receipts. When projected across the first 12 months, this increase amounts to an additional 5.92 receipts for the entire sample (i.e., 1,871 GP and orthodontic practices worldwide) and an additional 3.41 receipts for the subset of 319 low-volume, North American GPs.

The use of various biomaterials in computer-guided crestal sinus lift procedures. A report on two case studies with volume comparison

PURPOSE

In the context of the transcrestal maxillary sinus lift a wide variety of biomaterials have been used to fill the subantral space over the years. In this study, two types of biomaterials were used in order to fill the maxillary sinus: a nano-crystallized hydroxyapatite in an aqueous solution and a micronized heterologous bone in a collagen matrix.

MATERIALS AND METHODS

The surgical procedures were designed and carried out using computer-guided surgery. The filling volume obtained was measured with a comparative software program.

RESULTS

A ≥ 6 millimeter augmentation of osseous volume was obtained. This result is comparable to those obtained in lifts where conventional techniques were applied. The technique used was very precise and the difference between the projected and clinical outcome of the implant position had an average of less than 0.3 millimeters.

CONCLUSIONS

This technique allows for the surgery to be performed in a way which is both minimally traumatic and invasive, and represents a viable alternative to those surgical techniques for crestal sinus lift currently in use.

Development of an integrated staircase lift for home access

PURPOSE

Stairways into buildings present a significant environmental barrier for those with mobility impairments, including older adults. A number of home access solutions that allow users to safely enter and exit the home exist, however these all have some limitations. The purpose of this work was to develop a novel, inclusive home access solution that integrates a staircase and a lift into one device.

METHOD

The development of an integrated staircase lift followed a structured protocol with stakeholders providing feedback at various stages in the design process, consistent with rehabilitation engineering design methods.

RESULTS

A novel home access device was developed. The integrated staircase-lift has the following features: inclusivity, by a universal design that provides an option for either use of stairs or a lift; constant availability, with a lift platform always ready for use on either level; and potential aesthetic advantages when integrating the device into an existing home. The potential also exists for emergency descent during a power outage, and self-powered versions.

CONCLUSIONS

By engaging stakeholders in a user centred design process, insight on the limitations of existing home access solutions and specific feedback on our design guided development of a novel home access device.

Biological characterization of the skin of shortfin mako shark Isurus oxyrinchus and preliminary study of the hydrodynamic behaviour through computational fluid dynamics

This study characterized the morphology, density and orientation of the dermal denticles along the body of a shortfin mako shark Isurus oxyrinchus and identified the hydrodynamic parameters of its body through a computational fluid-dynamics model. The study showed a great variability in the morphology, size, shape, orientation and density of dermal denticles along the body of I. oxyrinchus. There was a significant higher density in dorsal and ventral areas of the body and their highest angular deviations were found in the lower part of the mouth and in the areas between the pre-caudal pit and the second dorsal and pelvic fins. A detailed three-dimensional geometry from a scanned body of a shark was carried out to evaluate the hydrodynamic properties such as drag coefficient, lift coefficient and superficial (skin) friction coefficient of the skin together with flow velocity field, according to different roughness coefficients simulating the effect of the dermal denticles. This preliminary approach contributed to detailed information of the denticle interactions. As the height of the denticles was increased, flow velocity and the effect of lift decreased whereas drag increased. The highest peaks of skin friction coefficient were observed around the pectoral fins.

The influence of the hand's acceleration and the relative contribution of drag and lift forces in front crawl swimming

The aim of this study was to assess the effect of the hand's acceleration on the propulsive forces and the relative contribution of the drag and lift on their resultant force in the separate phases of the front crawl underwater arm stroke. Ten female swimmers swam one trial of all-out 25-m front crawl. The underwater motion of each swimmer's right hand was recorded using four camcorders and four periscope systems. Anatomical landmarks were digitised, and the propulsive forces generated by the swimmer's hand were estimated from the kinematic data in conjunction with hydrodynamic coefficients. When the hand's acceleration was taken into account, the magnitude of the propulsive forces was greater, with the exception of the mean drag force during the final part of the underwater arm stroke. The mean drag force was greater than the mean lift force in the middle part, while the mean lift force was greater than the mean drag force in the final part of the underwater arm stroke. Thus, swimmers should accelerate their hands from the beginning of their backward motion, press the water with large pitch angles during the middle part and sweep with small pitch angles during the final part of their underwater arm stroke.

The endonasal lip lift: personal technique

Given the shortcomings of current methods to shorten the cutaneous upper lip, the senior authors modified the traditional subnasal lip lift with endonasal flaps, performing 311 such lifts over a 15-year period. Ideal surgical candidates are adults with tall philtra, negligible dental show, and no maxillary abnormalities. Benefits of the procedure include improved scar appearance and pout, absence of tension in visible areas, increased dental and vermilion display, and minimal scar migration (ie, loss of lift). Moreover, caudal rhinoplasty procedures are facilitated via the same incision sites. Undercorrection, sill widening, and alar distortion are mostly avoidable (or at least corrigible) complications. Nasal sill disruption, however, remains an inevitable drawback that may be minimized through meticulous technique.

Structure of the vortex wake in hovering Anna's hummingbirds (Calypte anna)

Hummingbirds are specialized hoverers for which the vortex wake has been described as a series of single vortex rings shed primarily during the downstroke. Recent findings in bats and birds, as well as in a recent study on Anna's hummingbirds, suggest that each wing may shed a discrete vortex ring, yielding a bilaterally paired wake. Here, we describe the presence of two discrete rings in the wake of hovering Anna's hummingbirds, and also infer force production through a wingbeat with contributions to weight support. Using flow visualization, we found separate vortices at the tip and root of each wing, with 15% stronger circulation at the wingtip than at the root during the downstroke. The upstroke wake is more complex, with near-continuous shedding of vorticity, and circulation of approximately equal magnitude at tip and root. Force estimates suggest that the downstroke contributes 66% of required weight support, whereas the upstroke generates 35%. We also identified a secondary vortex structure yielding 8-26% of weight support. Lift production in Anna's hummingbirds is more evenly distributed between the stroke phases than previously estimated for Rufous hummingbirds, in accordance with the generally symmetric down- and upstrokes that characterize hovering in these birds.