Index Of Curvature Research Articles

Combined corneal biomechanical and tomographical indices in subclinical and forme fruste keratoconus.

Evaluation of combined corneal tomographic and biomechanical parameters in subclinical/forme fruste keratoconus (ScKC/FFKC). Cross-sectional observational case-control study. Thirty-one eyes with ScKC (fellow eye of KC with any one sign: keratometry >47 diopters, cylinder >1.5 D, central corneal thickness <500 µm, with/without abnormal topography) or FFKC (fellow eye of KC with normal topography and slit lamp examination) >13 years (cases) and 44 eyes of age-matched 22 healthy subjects (controls). Clinically diagnosed KC, presence of corneal scars, and prior ocular surgery eyes. Sixteen Pentacam, 15 Corvis ST, and five Sirius parameters were analyzed using paired sample t -test, and a subsample found to be significantly different was used in receiver operating characteristic curve analysis. The Youden index was calculated, and Pearson's correlation analysis was done. Five Pentacam, three Corvis ST, and two Sirius parameters had an area under curve (AUC) >0.75. Tomographic and biomechanical index (TBI) (cutoff 0.59, 95% specificity, 77% sensitivity), Belin Ambrosio enhanced ecstasia display (cutoff 1.8, 81% specificity, 80% sensitivity), and symmetry index of posterior corneal curvature (cutoff 0.16, 97% specificity, 67% sensitivity) best identified early KC. TBI strongly correlated with maximum Pentacam parameters in both cases and controls. Corvis biomechanical index strongly correlated only in cases, and SP-A1-SD weakly correlated in cases. Upon combined analysis, the average sensitivity and specificity, respectively, of top three parameters (according to AUC) from Pentacam and Corvis ST were 74.1% and 95.4% for posterior elevation and TBI. The trial was registered in Clinical Trial Registry of India on January 28, 2022. The Trial Registration Number is REF/2022/01/050638.

Ways of increasing the efficiency of physical exercises of teenage school students with impaired health

The work is devoted to the definition of anatomical and physiological features of the formation of the movement culture of schoolchildren. The relevance of the issue of increasing the effectiveness of physical exercise classes for primary school girls with postural disorders is substantiated and is the formation of a culture of movements. It has been established that postural disorders are a prerequisite for the appearance of accompanying diseases and abnormalities in physical development and negatively affect the culture of movements, distorting the physique, plasticity of movements, gait, impair motor achievements during physical exercises, lead to a decrease in motivation for motor activity, negatively affect well-being children, lead to the emergence of psychological complexes and complicate socialization in the student body. According to the index method, which included the determination of the shoulder index, which characterizes the level of stooping (kyphotic posture), and the index of vertical curvature of the spine, which indicates the presence of scoliotic posture, it was found that 26.3% of schoolgirls have various posture disorders, while 82 of them .8% of girls have slouching (kyphotic posture), the other 17.2% of schoolgirls have scoliotic posture in various variants of vertical curvature of the spine. Since the level of some motor indicators indirectly determines the culture of girls' movements and affects the formation of a posture stereotype, pedagogical testing of various types of strength, coordination abilities and flexibility of elementary school students was conducted. At the same time, a significant difference was recorded between the motor development of schoolgirls with various postural disorders in the indicators of strength endurance of the muscles of the abdomen, back, flexibility, plasticity and static balance of healthy girls and schoolgirls with postural disorders. The conducted linear correlation analysis using the Pearson method between posture indicators and movement indicators showed a reliable relationship of moderate strength between the posture indicator and some movement indicators, which justifies the need to develop a methodology for teaching the movement culture of elementary school students with posture disorders in the process of physical education.

Assessing Spatiotemporal and Quality Alterations in Paretic Upper Limb Movements after Stroke in Routine Care: Proposal and Validation of a Protocol Using IMUs versus MoCap.

Accurate assessment of upper-limb movement alterations is a key component of post-stroke follow-up. Motion capture (MoCap) is the gold standard for assessment even in clinical conditions, but it requires a laboratory setting with a relatively complex implementation. Alternatively, inertial measurement units (IMUs) are the subject of growing interest, but their accuracy remains to be challenged. This study aims to assess the minimal detectable change (MDC) between spatiotemporal and quality variables obtained from these IMUs and MoCap, based on a specific protocol of IMU calibration and measurement and on data processing using the dead reckoning method. We also studied the influence of each data processing step on the level of between-system MDC. Fifteen post-stroke hemiparetic subjects performed reach or grasp tasks. The MDC for the movement time, index of curvature, smoothness (studied through the number of submovements), and trunk contribution was equal to 10.83%, 3.62%, 39.62%, and 25.11%, respectively. All calibration and data processing steps played a significant role in increasing the agreement. The between-system MDC values were found to be lower or comparable to the between-session MDC values obtained with MoCap, meaning that our results provide strong evidence that using IMUs with the proposed calibration and processing steps can successfully and accurately assess upper-limb movement alterations after stroke in clinical routine care conditions.

Understanding and Improving Risk Assessment of Abdominal Aortic Aneurysm Growth Using Statistical Shape Modeling of the Infrarenal Aorta

Maximum diameter of the aneurysmal sac remains the primary method for defining surveillance intervals and the timing for surgical intervention. Recent studies have attempted to expand on this one-dimensional metric by incorporating additional descriptors of the aneurysmal sac such as undulation, curvature and tortuosity. However, these metrics are often biased and may overlook certain anatomical abnormalities, limiting predictive potential. This study aimed to identify novel three-dimensional shape features of the aneurysmal flow lumen and outer wall structure (OWS, with or without intraluminal thrombus) to predict aneurysmal growth. A cohort of 192 patients (median age, 72 [range, 62-79]; 99% male) with infrarenal abdominal aortic aneurysms (AAAs) (initial max diameter, 50.3 ± 4.2 mm) and serial computed tomography images obtained during AAA surveillance (median follow-up, 2.0 years [range, 1.0-5.3 years]) were retrospectively considered for this study. Estimated annual AAA growth was the clinical end point and was used to classify patients into slow (first quintile, <2.5 mm/year) and fast (fifth quintile, >5.0 mm/year) cohorts. A previously validated pipeline was implemented to automatically segment computed tomography images. Three-dimensional statistical shape models of the aneurysmal flow lumen and OWS were used to identify three-dimensional patterns involved in AAA growth. Undulation index and radius of curvature of the AAA, previously suggested to be predictive of AAA growth, were also calculated. Model training with derived shape features was performed using iterated 10-fold optimization with shuffling (100 iterations). C-statistics for each feature combination was used to evaluate performance. Integrating the lumen and OWS as unique components within the three-dimensional statistical shape model captured the lumen-thrombus interface. These features proved to be superior to max diameter, undulation index, and radius of curvature in prediction of AAA growth phenotype (P < .001). Corresponding median C-statistics for predicting slow and fast growth are highlighted in the Figure. Integrated models outperformed individual components in prediction of both slow and fast AAA growth (P < .001). Standardized feature extraction from both the aneurysmal flow lumen and the OWS, enabled by a fully automated pipeline, can characterize the evolving lumen-thrombus interface, and improves AAA growth prediction. Future work is focused on validating this statistical shape-based model on larger cohorts that also include smaller AAAs.

Alteration in corneal topography asymmetry indices following corneal refractive surgery

Purpose We aimed to follow up corneal refractive asymmetry index changes following refractive surgery for cornea after correction of low-grade myopia and to determine which technique causes marked affection of the indices. Patients and methods This prospective study conducted from October 2020 to December 2021 included two groups of patients, the photorefractive keratectomy (PRK) group and the laser in-situ keratomileusis (LASIK) group. Every patient in each group had to follow a schedule of visits after surgery for the next day, 1 week, 1 month, and after 3 months. Patients who failed to follow this schedule were excluded from the study. Results The PRK group contained 42 eyes with a mean uncorrected visual acuity that improved significantly, corneal power (K-reading) and pupil center thickness reduced significantly. Surface variance index, central keratoconus index, and height decentration index did not change significantly. Vertical asymmetry index and minimum radius of curvature (Rmin) increased significantly while height asymmetry index decreased significantly. Our LASIK group contained 40 eyes that underwent changes similar to those in the PRK group regarding uncorrected visual acuity, the K-reading, and the pupil center thickness. The surface variance index, vertical asymmetry index, and height asymmetry index, height decentration index and Rmin increased significantly while the central keratoconus index decreased significantly. The keratoconus index reduced significantly in both groups. Conclusion The PRK is a more conservative technique than the LASIK technique regarding the affection of corneal asymmetry indices.

Spatio-temporal variations of a meandering channel morphodynamics: A study along the Kaljani River in Bhuchungmari-Moamari Section of North Bengal Dooars, West Bengal (India)

Rivers being the most dynamic and natural engines receive the maximum outcome of process-form activities over space and time. Displacement and shifting of course of the alluvial channels over the lower gradients result into severe bed-bank scouring activities temporally. River Kaljani within the neo tectonically active zone of North Bengal plains is an example of temporal variations of high sinuosity and braiding over the softer lithology. The present work is focusing on a temporal study from 1970 to 2019. The SOI Topographical map of 1:50,000 scales has been the base layer along with temporal satellite imageries (1990, 2000, 2010 and 2019). The schematization has followed digitization, rectification and overlaying of conformal layers extracted from the USGS website under UTM Projection system and WGS of 1984 datum for north 45 zones under GIS platform. Multi-temporal satellite data identified serious course changes of the selected reach of lower segment of Kaljani River. The rectified multi-spectral bands are used to make the NDWI for identification of the water content on earth surface followed by selective morphometric analysis e.g. sinuosity index, braided index and roundness of curvature to access the spatio-temporal changes accomplishing some derivative mathematical equations. Descriptive statistics viz. mean, standard deviation (SD), coefficient of variation (CV), skewness and kurtosis were used and explained maximum course oscillations. The authors tried to examine the fact for six temporal frames i.e. 1970, 1990, 2000, 2006, 2010 and 2019 and received high sinuosity of all categories. Conclusively the work claims to set a documentary approach to examine the morphodynamics of an alluvial channel of Sub-Himalayan foothills.

Running and Running of the Running of the Scalar Spectral Index in Warm Inflation

The next generation of cosmological observations are expected to improve the measurements of several quantities connected to the primordial inflation in the early Universe. These quantities include, for example, improved measurements for the spectral index of the scalar curvature of the primordial power spectrum and to also bring a better understanding on the scaling dependence of the primordial spectrum. This includes the running of the tilt and possibly, also, the running of the running. In this paper, we investigate the possibility of generating large runnings in the context of warm inflation. Useful analytical expressions for the runnings are derived in the context of warm inflation in the large dissipation regime. The results are compared to and discussed for some well-motivated primordial inflaton potentials that have recently been of interest in the literature.

Posture correction in children 11-12 years old by means of swimming with elements of aquafitness

The article is devoted to the justification of the use of a physical therapy program using swimming equipment to improve the physical condition of children aged 11-12 years with postural disorders. The relevance of the study is due to the critical sharp increase in the incidence of disease among children all over the world, in particular, in Ukraine in recent years. The evaluation method was the measurement of Moshkov's rhombus, acromial, digital, iliac crest and lower angles of the scapula of the point. According to the results of the study, it was found that among boys aged 11-12 years under the influence of classes under the rehabilitation program using swimming equipment with elements of aquafitness, the number of people with an index of vertical curvature of the spine of 100.0-90.0% increased by 30.77%, among girls - by 38.46%. At the same time, the number of persons with a spine curvature index of 79.9-70.0% in the main groups of boys and girls decreased significantly compared to the control groups. The feasibility of using the proposed program of complex rehabilitation with the use of swimming equipment with the use of elements of aquafitness was proven due to a significant improvement in the indicators of posture assessment in the studied children 11-12 years old.

Effects of rigid gas permeable contact lens on morphological parameters and vision-related quality of life in keratoconus patients.

To evaluate the effect of rigid gas permeable contact lens (RGP-CL) on corneal morphological parameters and vision-related quality of life in keratoconus (KC) patients. Totally 57 eyes of 30 KC patients who were followed-up for more than two years, including 17 RGP wearers (32 eyes) and 13 non-wearers (25 eyes) were retrospectively analyzed. Initial medical history and corneal topography were collected at baseline. Corneal topography, corneal aberration, optical coherence tomography, and vision-related quality of life questionnaires were performed at the last follow-up. According to corneal topography, increase of the flattest keratometric values was higher in RGP wearers than in non-wearers (P=0.038). The morphological parameters, including symmetry index of front corneal curvature (P=0.004) and Baiocchi-Calossi-Versaci index front (P=0.047), were lower in RGP wearers than in non-wearers. Vertical coma was smaller in RGP wearers than non-wearers in 3.0, 5.0, 6.0, and 7.0 mm pupil diameters, respectively (P<0.05). The environmental triggering domain of ocular surface disease index was worse in RGP wearers as compared to non-wearers (P=0.003). At the last follow-up, there were no significant differences in constituent ratios of KC progression, corneal thickness topography, epithelial thickness topography, morphological parameters of corneal topography, and other questionnaire scores between the two groups (all P>0.05). Long-term use of RGP does not worsen KC but may cause corneal epithelial remodeling to increase symmetry of corneal anterior surface, reduce corneal vertical coma and improve visual quality. However, RGP wearing causes a slight decrease in vision-related quality of life. The occurrence of ocular surface symptoms is mainly associated with environmental triggering factors.

A Pilot Study of Compensatory Strategies for Reach-to-Grasp-Pen in Patients with Stroke.

Coordinated reaching and grasping movements may be impaired in patients with poststroke hemiplegia. Patients frequently adopt compensatory strategies, which require investigation. This pilot study used kinematic parameters to examine compensatory strategies by assessing the reach-to-grasp-pen movements in patients with stroke and unaffected participants. Twelve patients with stroke with mild impairment (45.16 ± 12.62 years, 2.41 ± 1.97 months), twelve with moderate impairment (50.41 ± 12.92 years, 3.83 ± 3.58 months), and ten healthy individuals (20.6 ± 0.69 years) performed a reach-to-grasp-pen task. Kinematics parameters of upper limb and fingers, such as movement time, number of movement units, index of curvature, spectral arc length, trunk forward transition, trunk lateral transition, elbow extension, shoulder flexion, shoulder abduction, trunk rotation, arm-plane angle, the joint angles of interphalangeal joints of the thumb, index, middle, ring, and little fingers were examined in the study. These parameters were evaluated with two Microsoft Azure Kinect and Leap Motion, which belong to markerless motion capture systems. Patients with stroke showed longer reaching movement time, less smooth movement trajectories, and more trunk rotation (P < 0.05). In patients with stroke, the metacarpophalangeal joint (MCP) and proximal interphalangeal joint (PIP) of the thumb were flexed in the starting position; the MCP and PIP joints of the index finger in the stroke group were more extended during pen grasp; the range of motion of the MCP of the middle finger and the PIP joints of the middle, ring, and little fingers became greater, suggesting a larger peak aperture (P < 0.05). The more significant extension was observed in the index finger at the end of the grasp, suggesting inadequate flexion (P < 0.05). In clinical practice, the reach-to-grasp-pen task using markless sensing technology can effectively distinguish patients with stroke from healthy individuals and evaluate the recovery and compensation strategies of upper limb and hand functions. It can potentially become an evaluation tool in hospital and community scenes. Accurate identification of abnormal trunk, arm, and finger strategies is crucial for therapists to develop targeted upper limb treatment methods and evaluate treatment effects.

Long term complications of penile fracture repair: Erectile dysfunction and penile curvature

ObjectiveTo determine the factors that cause erectile dysfunction and penile curvature after repair of penile fracture (PF). MethodsData from 25 patients who underwent PF repair was retrospectively analyzed. PF was diagnosed by examining patients’ medical histories and performing physical examinations. All patients underwent immediate PF repair. All patients filled out the International Index of Erectile Function (IIEF-5) form and penile curvature was examined. ResultsThe median age of patients at the time of surgery and the median follow-up duration were 46 years (22–60 years) and 95 months (12–156 months), respectively. Two of the patients had concomitant urethral injury. At the final follow up, erectile dysfunction (ED) was present in 13 patients (52%). Among these patients, 9 patients (36%) had mild ED and 4 patients (16%) had moderate ED. With a univariate analysis, age and penile curvature were significantly associated with ED (p=0.008 and p=0.039, respectively). With a multivariate analysis, age was independently associated with ED (p=0.048, odds ratio=1.104, 95% confidence interval 1.000–1.218). The IIEF-5 scores correlated with age (p=0.009, r=0.510). Seven patients (28%) had penile curvature and one patient underwent penile plication surgery. ConclusionAfter PF repair, age is the only risk factor for ED and penile curvature rarely requires surgical treatment.

Deflection bowl parameters for falling weight deflectometer testing: data collection and threshold benchmarking

ABSTRACT Deflection Bowl Parameters (DBP) has been used widely to evaluate pavement structural performance based on deflection data from Falling Weight Deflectometer (FWD). However, due to different pavement layers, materials configuration, test load, and climatic temperature, DBP thresholds need to be established for urban streets in tropical countries like Singapore. Around 130 km of field data in the network was collected every 25 m span, processed using Elmod 6 software before regression analysis. Based on the high coefficient of determinations (R-squared > 0.65), the DBP thresholds were proposed mainly for the middle layer condition (using Middle Layer Index, Lower Layer Index and Maximum deflection) and subgrade condition (via Lower Layer Index). In contrast, there were still some uncertainties in parameters related to HMA surface layers (by using Base Layer Index and Radius of Curvature) due to lower levels of R-squared (≅ 0.5). Our results have filled the research gaps of field-validated DBP thresholds for FWD 50 kN on the thick bituminous base pavement: Hot Mix Asphalt 130-170 mm, Graded Granite Aggregate Base 200-250 mm, and infinite subgrade. The findings have contributed to newly established DBP thresholds for immediate implementation in Singapore and other countries sharing similar pavement configurations.

The immediate effect of different loads does not alter muscle co-activation of the upper limb in young adults with dyskinetic cerebral palsy.

There is insufficient information on muscle co-activation in the upper limbs to help healthcare providers develop treatment programs for patients with dyskinetic cerebral palsy (DCP). Is the degree of muscle co-activation greater in adults with DCP than in healthy individuals? Does the use of different arm weights modify co-contraction in individuals with PCD? Fourteen healthy individuals (control group [CG]) and 14 individuals with DCP (dyskinetic group [DG]) participated in the study. The degree of muscle co-activation of the dominant limb during drinking from a mug was compared between the two groups. The task was divided into a going, adjusting, and returning phase. In the DG, an analysis was also performed on using an arm weight during the functional task. The loads corresponded to 10, 20, and 30 % of maximum isometric muscle strength measured in each participant. In comparing the two groups, the DG exhibited a greater muscle co-activation in the shoulder and elbow muscles during the going phase, the shoulder, elbow, and wrist during the adjusting phase; and the elbow during the returning phase. The DG also showed a greater mean index of curvature (MIC), time to perform the movement phases, and lesser mean velocity (Vm) to drinking. In analyzing the DG's arm weight, no effect on co-activation, MIC, time to perform the movement phases, and Vm to drinking were found with the loads tested (p > 0.05). Muscle co-activation is increased in adults with DCP in comparison to healthy individuals. Moreover, arm weight during the functional activity of drinking from a mug did not alter co-activation, although an immediate effect was expected.

Changes of corneal topography indices after corneal collagen crosslinking for treatment of keratoconus assessed by scheimpflug camera

Introduction Keratoconus is a bilateral, progressive ectasia of the cornea resulting in irregular astigmatism and myopia. We can use spectacles or contact lenses to correct the symptoms of keratoconus, whereas in advanced cases, corneal grafting is the only treatment. Corneal collagen cross-linking (CXL) is a promising treatment to strengthen and stabilize the cornea in cases of keratoconus. Aim To evaluate changes in corneal topography indices after corneal CXL in patients with keratoconus and analyze these changes. Patient and methods CXL was performed in eyes with keratoconus. Quantitative descriptors of corneal topography were measured with the Pentacam topographer and included seven indices: index of surface variance, index of vertical asymmetry, keratoconus index, central keratoconus index, minimum radius of curvature, index of height asymmetry, and index of height decentration. Follow-up was 6 months. Results The study comprised 50 eyes of 35 patients with keratoconus. In the entire patient cohort, there were significant improvements in the index of surface variance, index of vertical asymmetry, keratoconus index, and minimum radius of curvature at 6 months compared with baseline (all P Conclusion There were improvements in four of seven topography indices 6 months after CXL, suggesting an overall improvement in corneal shape.

Prediction of Abdominal Aortic Aneurysm Growth Using Geometric Assessment of Computerized Tomography Images Acquired During the Aneurysm Surveillance Period.

We investigated the utility of geometric features for future AAA growth prediction. Novel methods for growth prediction of AAA are recognized as a research priority. Geometric feature have been used to predict cerebral aneurysm rupture, but not examined as predictor of AAA growth. Computerized tomography (CT) scans from patients with infra-renal AAAs were analyzed. Aortic volumes were segmented using an automated pipeline to extract AAA diameter (APD), undulation index (UI), and radius of curvature (RC). Using a prospectively recruited cohort, we first examined the relation between these geometric measurements to patients' demographic features (n = 102). A separate 192 AAA patients with serial CT scans during AAA surveillance were identified from an ongoing clinical database. Multinomial logistic and multiple linear regression models were trained and optimized to predict future AAA growth in these patients. There was no correlation between the geometric measurements and patients' demographic features. APD (Spearman r = 0.25, P < 0.05), UI (Spearman r = 0.38, P < 0.001) and RC (Spearman r =-0.53, P < 0.001) significantly correlated with annual AAA growth. Using APD, UI, and RC as 3 input variables, the area under receiver operating characteristics curve for predicting slow growth (<2.5 mm/yr) or fast growth (>5 mm/yr) at 12 months are 0.80 and 0.79, respectively. The prediction or growth rate is within 2 mm error in 87% of cases. Geometric features of an AAA can predict its future growth. This method can be applied to routine clinical CT scans acquired from patients during their AAA surveillance pathway.

Optimal Multifield Functional Electrical Stimulation Parameters for the “Turn on the Light” Task and Related Upper Limb Kinematics Repeatability in Poststroke Subjects

ObjectiveTo characterize the optimal functional electrical stimulation (FES) parameters that assist the turn on the light task (TOTL) on poststroke participants and to analyze the related upper limb (UL) kinematics repeatability. DesignCross-sectional study. SettingHuman movement research center. ParticipantsPoststroke individuals (N=11) with history of a single unilateral stroke that resulted in a motor control dysfunction of the contralesional UL. InterventionsFES based on surface multifield technology applied to the contralesional wrist and finger extensors during the TOTL. Main Outcome MeasuresFES outcome metrics (virtual electrodes, stimulation duration, intensity) and kinematic metrics (end-point kinematics [absolute and relative duration, mean and peak velocities, relative instant of peak velocity, index of curvature, number of movement units] and joint kinematics [shoulder, elbow, wrist end position and range of movement]). Outcome measures were assessed 2 times with a 72-hour maximum time interval. ConclusionIt was possible to establish reliable FES parameters that assisted the TOTL on poststroke participants. These stimulation parameters led to high to very high repeatability in terms of UL kinematics for most of the cases.

Spatiotemporal parameters from instrumented motion analysis represent clinical measurement of upper limb function in children with cerebral palsy

BackgroundThere are various tools that measure upper limb function in children with cerebral palsy(CP) clinically, but these measurement methods are examiner-dependent and scale values are not proportional to the upper limb function which makes it difficult to quantify the function. Research questionThe purpose of this study was to investigate whether the new parameters derived from 3D motion analysis reflect the upper limb function which measured by Melbourne Assessment 2 (MA2) in children with cerebral palsy (CP) compared to the clinical measurements. MethodsForty children with CP (24 boys, 16 girls; mean [SD] age, 6 years 11 months [3 years 5 months]) were recruited. Motion capture was conducted during phases T1–T4 of Reach and Grasp Cycles. New parameters (movement time, number of movement units, index of curvature) were derived from wrist marker data. Range of motion (ROM), accuracy, dexterity, and fluency of unilateral upper limb function were assessed using MA2. Spearman rank coefficients were determined to evaluate correlations between MA2 and the new parameters. Results and significanceIndex of curvature correlated negatively with MA2 accuracy scores during T1 (rs -0.347, p < 0.05), T2 (rs -0.471, p < 0.01), and T3 (rs -0.660, p < 0.01). Number of movement units correlated negatively with MA2 ROM, accuracy, and fluency scores during T1 (ROM rs -0.334; accuracy rs -0.331; fluency rs -0.375; p < 0.05) and T3 (ROM rs -0.499; accuracy rs -0.531; fluency rs -0.515; p < 0.01). Index of curvature and number of movement units are objective, simple parameters showing fair to good correlation with MA2 accuracy and fluency of upper limb function.

Adding Haptic Feedback to Virtual Environments With a Cable-Driven Robot Improves Upper Limb Spatio-Temporal Parameters During a Manual Handling Task.

Physical interactions within virtual environments are often limited to visual information within a restricted workspace. A new system exploiting a cable-driven parallel robot to combine visual and haptic information related to environmental physical constraints (e.g. shelving, object weight) was developed. The aim of this study was to evaluate the impact on user movement patterns of adding haptic feedback in a virtual environment with this robot. Twelve healthy participants executed a manual handling task under three conditions: 1) in a virtual environment with haptic feedback; 2) in a virtual environment without haptic feedback; 3) in a real physical environment. Temporal parameters (movement time, peak velocity, movement smoothness, time to maximum flexion, time to peak wrist velocity) and spatial parameters of movement (maximum trunk flexion, range of motion of the trunk, length of the trajectory, index of curvature and maximum clearance from the shelf) were analysed during the reaching, lowering and lifting phases. Our results suggest that adding haptic feedback improves spatial parameters of movement to better respect the environmental constraints. However, the visual information presented in the virtual environment through the head mounted display appears to have an impact on temporal parameters of movement leading to greater movement time. Taken together, our results suggest that a cable-driven robot can be a promising device to provide a more ecological context during complex tasks in virtual reality.

Modeling and numerical simulation of micropolar fluid over a curved surface: Keller box method

Background: This paper examines the flow behavior of micropolar liquid over a curved surface. MHD fluid is considered. The surface inducing the fluid motion has a prescribed temperature different from the ambient fluid moreover the heat transfer mechanism is investigated. Curvilinear coordinates are used for the mathematical formulation of the flow equation. Similarity variables are derived and are utilized to alter the governing expressions for the flow of momentum and heat transfer characteristic.Method: The resulting non-linear ODEs are resolved systematically by two numerically approaches namely; the Keller box method and the shooting method.Results: The numerical results for the temperature and velocity fields has been presented through tables and graphs against the independent parameters and non-dimensional numbers i.e., material parameter, power law index, radius of curvature, magnetic parameter, Prandtl and Eckert numbers, skin friction (drag force) and Nusselt number. Physical explanation of the graph presented is given to understand the performance of fluid flow and heat transport phenomena in different emerging situation.Conclusion: The main outcomes in the presence of various flow variables on the skin friction velocity, Nusselt number, temperature are highlighted via graphical sketch and Tables. Velocity field displays a decreasing trend with magnetic parameter, power law index and radius of curvature of the stretching velocity whereas, opposite behavior observed for the material parameter. Near the surface curvature and magnetic parameter shows an enhancement in microrotation profile whereas, it shows reverse behavior when it is far away. Material parameter increases for large values of microrotation profile on the other hand power-law index decreases for large values. For higher values magnetic parameter, radius of curvature and Eckert number temperature profile increases. But temperature reduces subject to material parameter and Prandtl number.

Interspecific variations in the surface wettability and morphological traits of petals across 125 plant species

Petal wettability is an important characteristic of flowering plants, as excess surface water on a petal can cause color loss and collapse of shape. However, few studies have examined natural variations in the wettability and the related morphological traits of petals. The present study investigated these characteristics across 125 species from a warm temperate habitat (Tokyo, Japan) by evaluating the contact angles (CAs) of water droplets on the petal epidermis as an index of surface wettability and cell curvature (= cell height/width) and the presence of epicellular structures, such as cuticular folds and trichomes as an index of the petal surface roughness. We found that more than half of the species possessed convex epidermal cells with epicellular structures. In addition, the majority of species had petals with low wettability (CAs varying between 90 and 140°), and only 2.4% and 12% of species possessed super-hydrophobic and hydrophilic petals, respectively. This natural distribution of petal wettability was less variable than that of leaves. Among the less wettable petals (CA > 90°), there was also a significant correlation between cell curvature and CA, and this relationship differed between the adaxial and abaxial sides. To assess the ecological importance of petal wettability, its relationships with life form and flower direction were examined. This showed that herbaceous plants have more convex epidermal cells than woody plants, but no significant difference was detected in their CAs. Besides, among upward-facing flowers, the adaxial side had a more convex and less wettable epidermis compared to the abaxial side, which may protect sky-facing adaxial epidermis from wetting by raindrops. However, there was no significant difference in these features between the adaxial and abaxial sides of sideward- and downward-facing flowers. The less clear tendency of petal wettability was attributable to multiple functions of the petal surface.