•An individual tree detection and segmentation approach based on trunk point distribution is proposed.•The approach can effectively detect tree trunks even if trunk points are sparse.•Trunks of ...relatively low trees are differentiated from high understory vegetation.•The approach derived overall accuracies between 0.920 and 1.000.
The light detection and ranging (LiDAR) systems mounted on unmanned aerial vehicle (UAV) platforms can provide high-density point cloud data for accurate individual tree detection and segmentation, which is needed for precision forestry. Individual trees can be detected and segmented based on tree trunk detection. It is a challenging task in forests characterized by high understory vegetation and varying point densities of trunks caused by obstruction from the upper canopy. We propose an approach to detect tree trunks and segment individual trees from UAV-LiDAR data. First, a trunk point distribution indicator (TPDI) was used to detect potential tree trunk positions (PTPs). Then random sample consistency (RANSAC)-based 3D line fitting was applied to each PTP to differentiate tree trunks from understory vegetation. Finally, a trunk-based region-growing segmentation method was applied to segment individual trees, and the result was refined through analysis of crown shape and vertical profiles. The approach was tested at three study sites in Eucalyptus plantations, which were characterized by overlapping crowns and relatively high understory vegetation. F-scores ranging from 0.920 to 1.000 were derived in 12 plots, and the accuracies increased with the tree heights. The comparative shortest-path algorithm for tree trunk detection and segmentation was applied for comparison and derived much lower F-scores (0.526–0.867). The proposed approach was also evaluated by replacing TPDI with a similar indicator. The comparison result indicated that the proposed approach was especially advantageous in forests characterized by relatively low tree heights and high understory vegetation.
Abstract
OBJECTIVES
We evaluated the operative and long-term outcomes of the frozen elephant trunk (FET) technique for acute type A aortic dissection.
METHODS
This study evaluated 426 consecutive ...patients who underwent aortic repair for acute type A aortic dissection from June 2007 to December 2018 at our centre. Of these, 139 patients underwent total arch replacement with FET (FET group), and 287 underwent other procedures (no FET group). Ninety-two patients in the FET group were matched to 92 patients in the no FET group by using propensity score matching analysis.
RESULTS
Thirty-day mortality and neurological dysfunction were not significantly different between the FET and no FET groups (1.4% vs 2.4%, P = 0.50 and 5.0% vs 6.3%, P = 0.61, respectively). Long-term survival was better in the FET group than in the no FET group (P = 0.008). Freedom from distal thoracic reintervention was similar in the FET and no FET groups (P = 0.74). In the propensity-matched patients, freedom from aortic-related death was better in the FET group than in the no FET group (P = 0.044).
CONCLUSIONS
Operative outcomes showed no significant difference between the 2 groups. FET contributes to better long-term survival in patients with acute type A aortic dissection.
The strength of the lateral flexor muscles in the trunk is necessary for maintaining stability in the rib cage, spinal column, and preventing a higher number of injuries, while also enhancing overall ...trunk muscle strength. This study, conducted in a transversal manner, aimed to identify gender-based differences in the strength of trunk lateral flexor muscles among university athletes in the younger senior age group. The study involved 46 athletes from the University of Novi Sad, comprising 25 male participants (height =181.27±6.28 cm; weight =78.31±12.14 kg; BMI =23.78±3.13 kg/m2; mean age =23.75±0.30) and 21 female participants (height =168.19±5.48 cm; weight = 3.72±5.94 kg; BMI =22.53±7.78 kg/m2; mean age =23.68±0.22). The results of the independent t-test revealed no statistically significant differences between the two gender groups based on dimorphic characteristics (p>0.05) in the assessment of trunk lateral flexor muscle strength. It is essential to consider other aspects of the locomotor system specific to each sport and discipline to effectively prevent injuries during training and decrease the overall injury rate.
Objective
To assess the efficacy of two different passive back-support exoskeleton (BSE) designs, in terms of trunk muscle activity, perceived low-back exertion, and task performance.
Background
BSEs ...have the potential to be an effective intervention for reducing low-back physical demands, yet little is known about the impacts of different designs in work scenarios requiring varying degrees of symmetric and asymmetric trunk bending during manual assembly tasks.
Method
Eighteen participants (gender balanced) completed lab-based simulations of a precision manual assembly task using a “grooved pegboard.” This was done in 26 different conditions (20 unsupported; 6 supported, via a chair), which differed in vertical height, horizontal distance, and orientation.
Results
Using both BSEs reduced metrics of trunk muscle activity in many task conditions (≤47% reductions when using BackX™ and ≤24% reductions when using Laevo™). Such reductions, though, were more pronounced in the conditions closer to the mid-sagittal plane and differed between the two BSEs tested. Minimal effects on task completion times or ratings of perceived exertion were found for both BSEs.
Conclusion
Our findings suggest that using passive BSEs can be beneficial for quasi-static manual assembly tasks, yet their beneficial effects can be task specific and specific to BSE design approaches. Further work is needed, though, to better characterize this task specificity and to assess the generalizability of different BSE design approaches in terms of physical demands, perceived exertion, and task performance.
Application
These results can help guide the choice and application of passive BSE designs for diverse work scenarios involving nonneutral trunk postures.
Despite preliminary evidence demonstrating the relevance of trunk muscle strength for physical function in older adults, it is not clear which muscle-related trunk parameter is the best predictor for ...physical functions. Therefore, this study aimed to compare trunk muscle morphology or strength parameters regarding their predictive ability for physical functions.
Seventy-four older adults (38 men, 36 women, mean age 76.85 years) were tested for maximum absolute and relative isokinetic trunk flexion and extension strength, trunk lean mass, and trunk muscle quality. Functional assessment included normal and fast walking speed, repeated sit-to-stand transfer, timed up and go, and postural sway during a closed-feet and a semi-tandem stance adjusted for body height. Pearson's correlations were used to compare relationship between trunk strength adjusted and unadjusted for body weight to physical functions. Linear regression analysis including sex and age as co-variables was performed between trunk muscle and functional test parameters.
Relative back extension strength was the most consistent significant predictor for all physical function tests (p = 0.004–0.04) except for postural sway. Relative trunk flexion strength was related to normal walking speed (p = 0.024). Trunk lean mass was related to timed up and go performance (p = 0.024).
Relative back extension strength is associated with better performance in nearly all standard tests for physical function in older adults, while trunk flexion strength and lean mass seem to play a minor role. Our findings emphasize the importance of trunk muscle strength, especially the back extensor muscles, for physical function in older adults.
To examine the management of distal aortic disease after total arch replacement with the frozen elephant trunk (TAR + FET) in patients with chronic thoracic aortic disease.
Two centre retrospective ...study of consecutive patients treated between January 2010 and December 2019. The primary endpoint was 30 day or in hospital death. The secondary endpoint was midterm survival. Data are presented as median (interquartile range IQR). The χ2 or Fisher’s exact test was used as appropriate. Estimated survival (standard error) was assessed by calculating the Kaplan–Meier product limit estimator with right censoring of survival data. A p value of < .050 was considered statistically significant. STROBE guidelines were followed.
A total of 158 patients (72 men; median age 70 years, IQR 64, 75; median distal aortic diameter 58 mm, IQR 46, 68; 127 aneurysmal disease, 31 chronic dissection) underwent TAR + FET. The peri-operative mortality rate was 10.1% (9/107 elective, 7/51 non-elective). Of 74 (46.8%) patients with a primary distal seal, seven (9.5%) died peri-operatively, the distal seal was maintained during follow up in 51, nine underwent late distal repair (two planned, seven unplanned; one open, eight endovascular; one peri-operative death) with a median interval to unplanned repair of 777 days (IQR 462, 1480), and seven with loss of seal had no intervention. Distal seal failed in 2/28 (7%) patients with a distal seal length > 30 mm and device oversizing > 10%, compared with 12/39 (31%) patients who did not meet these criteria (p = .031). In 84 patients without a primary distal seal, nine (10.7%) died peri-operatively, the distal aorta remained below the size threshold for repair during follow up in 12 patients, 44 had distal repair (median aortic diameter 64 mm, IQR 60, 75; eight open, one hybrid, 35 endovascular repairs; no deaths) at a median of 256 days (IQR 135, 740), and 19 did not have distal repair at the end of the follow up period: six died before planned repair at a median interval of 115 days (IQR 85, 120); eight were considered unfit; one was assessed as fit but declined; and four patients were awaiting assessment. Median follow up was 46 months (IQR 26, 75): no patients were lost to follow up. Estimated ± standard error five year survival was 61.5 ± 4.1%: elective 70.6 ± 4.7%, non-elective 43.2 ± 7.2%.
TAR + FET achieved primary distal seal in 47% of patients, but late failure occurred in 21%. Distal repair was ultimately indicated in 84% of survivors without a primary distal seal and of these 70% underwent repair, almost 10% died before planned repair, and 13% were considered unfit. Earlier distal endovascular repair and better assessment of patient fitness may improve midterm outcomes.
Infra-popliteal artery aneurysms are uncommon. While literature has begun to accumulate on these aneurysms, literature is relatively lacking with respect to the tibioperoneal trunk (TPT). We describe ...a case of a 71-year-old male who presented with a true, atherosclerotic TPT aneurysm associated with blue toe syndrome (BTS). Our surgical approach involved initial catheter directed thrombolysis followed by excision of the aneurysm with a reversed great saphenous vein (GSV) interposition graft. A review of the literature suggests that this is the first report of its kind. We also present a comprehensive review of the published literature on TPT.
Impairment of arm movements poststroke often results in the use of compensatory trunk movements to complete motor tasks. These compensatory movements have been mostly observed in tightly controlled ...conditions, with very few studies examining them in more naturalistic settings. In this study, the authors quantified the presence of compensatory movements during a set of continuous reaching and manipulation tasks performed with both the paretic and nonparetic arm (in 9 chronic stroke survivors) or the dominant arm (in 20 neurologically unimpaired control participants). Kinematic data were collected using motion capture to assess trunk and elbow movement. The authors found that trunk displacement and rotation were significantly higher when using the paretic versus nonparetic arm (P = .03). In contrast, elbow angular displacement was significantly lower in the paretic versus nonparetic arm (P = .01). The reaching tasks required significantly higher trunk compensation and elbow movement than the manipulation tasks. These results reflect increased reliance on compensatory trunk movements poststroke, even in everyday functional tasks, which may be a target for home rehabilitation programs. This study provides a novel contribution to the rehabilitation literature by examining the presence of compensatory movements in naturalistic reaching and manipulation tasks.
The center of the body is the trunk. For distal extremity movements, balance, and functional tasks, proximal trunk control is crucial. The aim of the study is to examine the relationship of trunk ...control with balance, upper extremity and lower extremity functions in stroke patients. Thirty-six stroke patients were included in this cross-sectional descriptive study. Trunk control was assessed using the Trunk Impairment Scale (TIS), Berg Balance Scale (BBS) was used for balance evaluation, Fugl-Meyer Lower Extremity Scale (FML) was used for lower extremity function evaluation, Fugl-Meyer Upper Extremity Scale (FMU) was used for upper extremity function evaluation. The mean age of the included stroke patients was 62±11 years. There was a moderate negative correlation between TIS and BBS (r=-0.610, p<0.01). A moderate negative correlation was found between TIS and FML (r=-0.520, p=0.001). A low negative correlation was found between TIS and FMU (r=-0.372, p=0.025). Trunk control affects balance, lower extremity and upper extremity function. In the treatment of stroke patients, exercise approaches for trunk control should be added to rehabilitation programs in addition to basic neurophysiological approaches.
Objective: The most common aortic arch branching variation described in literature is the common origin of the brachiocephalic trunk and left common carotid artery ("bovine arch" / type II aortic ...arch), with an incidence of 7.2-21.1%. The first aim of this study was to investigate the prevalence of bovine arch in the fetuses. The second aim was the hemodynamic evaluation of the epiaortic vessels.
Methods: In two years we examined 742 pregnant women and it was possible to obtain a good hemodynamic evaluation in 39 patients. Among the 39 fetuses, we found 6 with bovine arch. The blood flow of all epiaortic vessels and of MCA was evaluated.
Results: Among the 742 fetuses examined, the bovine aortic arch was identified in 45 patients (6.06%). The hemodynamic evaluation of the epiaortic vessels showed statistically significant differences between the bovine arch and normal aortic arch.
Conclusion: The presence of bovine aortic arch in the fetus is characterized by some hemodynamical differences. They could have a possible relationship with the incidence of some pathologies in adult life. Prenatal knowledge of anatomic variants of the aortic arch can bring benefits to the individual's health for future possible cardiovascular investigations.
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