Side Bending Research Articles

Study of dual pulse gas metal arc welding process characteristics on IS 2062 steel

Dual pulse gas metal arc welding (DP-GMAW) is a superior welding process where the weld quality and strength of weldment is highly dependent on weld input parameters. It is important to understand the effect of different input parameters on the effectiveness of welding, especially for commonly used mild steels such as IS 2062. This work attempts to study the effect of current, voltage, wire feed rate (WFR) and standoff distance (SOD) during DP-GMAW of IS 2062 steels. The interaction of WFR and varying welding current, voltage, weld pool geometry and %dilution was investigated through bead-on-plate weld method. A plate was welded using DP-GMAW process with a WFR of 8 m/min, SOD of 15 mm and a travel speed of 25 cm/min. The side and face bend tests of DP-GMA welded plates revealed that the weld quality was good without any crack. The hardness of the weld zone was significantly higher than the base metal. The strength, elongation and Charpy V-notch impact energy of the weldment was comparable to that of the base metal. A simultaneous increase of microhardness and toughness of the welded sample was observed. Metallographic tests revealed that this phenomenon was due to the presence of fine grain structure containing acicular ferrite and Widmanstatten ferrite in the weld metal which was generated due to the superimposition of current pulsation over thermal pulsation during DP-GMAW process.

Precise prediction of photothermally induced irreversible bending deformation based on non-uniform thermal expansion of layer-structure films

Although photothermally induced self-bending films based on nonuniform thermal expansion are created, heat transfer and shape-deformation procedures are not investigated very well, limiting the understanding of such complicated behavior and the achievement of precise shape control. Here, thermally expanded microspheres (TEMs) were added into polydimethylsiloxane (PDMS) to create active layers as PDMS-TEM single-layer films that were attached onto pure PDMS passive layer to create PDMS/PDMS-TEM bi-layer films subsequently. After heating, TEMs in the film undergo phase transition and present irreversible thermal expansion, driving deformation of films. Combined with steady-state (uniform heating) deformation simulations and experiments, a deformation model was established before a non-steady state (light irradiation) heat transfer model was set up to simulate the heat transfer process of films under light irradiation. Then the temperature distribution was coupled with the deformation model to simulate the photothermally induced deformation of the samples. The PDMS-TEM single-layer films also presented bending deformation under illumination due to the non-uniform thermal expansion caused by temperature gradient. For bi-layer films, different degrees of thermal expansion between two layers lead to bending deformation. The films with TEM concentration of 30 wt% can achieve great deformation, and the bending curvature was 0.07 mm−1. The geometric parameters including thickness, layer thickness ratio and aspect ratio had little effect on deformation degrees of the films. Deformation mode was varied with aspect ratio. A long side bending and diagonal bending were achieved in bi-layer films at aspect ratios of 7:1 and 1:1. In combination with experimental results, the heat transfer model and deformation model were constructed to demonstrate the complex deformation process, which provides guidance for the structural design of the photothermally induced shape-changing films in practical applications.

Side bending radiographs and lowest instrumented vertebra in adolescent idiopathic scoliosis: A French quality-of-care study

BackgroundDetermining which spinal levels to instrument during surgical treatment of Lenke Type 1 adolescent idiopathic scoliosis (AIS) depends on the reducibility of the primary and secondary curve patterns. This reducibility can be evaluated in several ways, with the most popular being radiographs in bending for moderate thoracic and lumbar curvatures.Hypothesis Side-bending radiographs will alter the choice of the lowest instrumented vertebra (LIV) for the surgical treatment of AIS. MethodsThirteen experienced French spine surgeons were invited to perform surgical planning on 23 patients based on stereoradiographs with and without (standing) side-bending views. The surgical planning was repeated a second time to assess the intra- and inter-rater reliability. Variations in the choice of LIV were analyzed for each evaluation. ResultsThe intra-rater reliability was moderate to substantial. The inter-rater reliability was low to moderate. The study compared 879 surgical plans. Selective fusion was chosen in 0.3% of the plans. The median LIV was L2. The availability of side bending views changed the plan in 39% of cases. However, 36% of the plans were changed in the control (test–retest) condition. No significant difference was found between the variations with side-bending radiographs and “control” variations (p>0.05). ConclusionThe use of radiographs in bending has no significant effect on the LIV choice in this study. This result is derived from statistically robust analysis made possible by one of the largest datasets available on this topic. Large inter-rater variability was observed and will be explored further in a future study. Level of evidenceII; non-randomized controlled comparative study.

Effect of post-isometric relaxation versus myofascial release therapy on pain, functional disability, rom and qol in the management of non-specific neck pain: a randomized controlled trial

BackgroundNon-specific neck pain is the most prevailing musculoskeletal disorder which has a large socioeconomic burden worldwide. It is associated with poor posture and neck strain which may lead to pain and restricted mobility. Physical therapists treat such patients through several means. Post isometric relaxation and Myofascial release therapy are used in clinical practice with little evidence to be firmed appropriately. So, this study was conducted to explore the effect of Post-isometric relaxation in comparison to Myofascial release therapy for patients having non-specific neck pain.MethodologySixty patients were randomly allocated to Post isometric group and the Myofascial group. The treatment period was of 2 weeks. All the patients were evaluated using the Visual analogue scale (VAS), Neck disability index (NDI), Universal Goniometer, and WHO BREF Quality of life-100 in the 1st and 6th sessions. Recorded data was entered on SPSS 21. Data were examined using two-way repeated ANOVA to measure the variance of analysis (group x time).ResultsAnalysis of the baseline characteristics revealed that both groups were homogenous in terms of age and gender i.e. a total of 60 participants were included in this research study 30 in each group. Out of 60 patients, there were 20(33.3%) males and 40(66.7%) females with a mean age of 32.4(5.0) years. Participants in the Post Isometric group demonstrated significant improvements (p < 0.025) in VAS, NDI, Cervical Extension, left side rotation ranges, and QoL (Social Domain) at the 2-week follow-up compared with those in the Myofascial group. In addition, the Myofascial group indicated significantly better improvement in the mean score of CROM (flexion and right and left side bending).ConclusionThe study demonstrated patients with nonspecific neck pain can benefit from the post isometric relaxation with significant improvement in pain, disability, cervical ROM, and Quality of life compared with myofascial release therapy.Trial registrationClinical Trial registered on clinicaltrial.gov (NCT number) NCT04638062, 20/11/2020 (prospectively registered).

Comparative Efficacy of Isometric versus Dynamic Exercises on Cervical Spondylosis

Cervical spondylosis is a degenerative disorder in the neck that is very common and worsens with age: it can limit the ability to participate in normal activities and is also costly to treat. The purpose of this study was to observe the effect of isometric and dynamic exercises on cervical spondylosis. This study was conducted at the center for physical therapy and rehabilitation in “Banja e Kllokotit”, Kllokot, Kosovo. The total number of patients included in the study was 60 people of both sexes, who were randomly divided into two groups (group A, n=30; group B, n=30) and received ten sessions of physical therapy. Group A was treated with thermotherapy, electrotherapy, dynamic exercises for the muscles of the cervical region, stretching and deep transverse massage; while group B was treated with thermotherapy, electrotherapy, isometric exercises, and stretching. Range of motion was measured with a standard goniometer, while the level of pain was estimated by the numerical rating scale of pain (NRS). Evaluation of patients was done before and after ten sessions of treatment. The results showed significant difference between groups related to mobility in flexion (P=0.052), extension (P =0.743) side bending (P&lt;0.000) and pain parameters (P&lt;0.000); the group of patients treated with dynamic exercise showed better results and performance after 10 sessions of physical therapy. It can be concluded that dynamic exercise produces better results compared to isometric exercises.

Evaluasi Desain Lengkung Horizontal Jalan Raya Pada Kawasan Wisata Alam Arak-Arak Kabupaten Bondowoso Jawa Timur

The road is one of the transportation infrastructures that have a role as a connector between regions, and also contributes to the strengthening and growth of the economy, society, tourism, and culture of a region. Today, tourism activity in Indonesia is growing rapidly, marked by the increasing number of tourist areas being built, one of which is the Arak-Arak natural tourism area in the Bondowoso Regency, East Java. Located in a hilly area with an altitude of 345 meters above sea level, with hilly terrain characteristics. Horizontal curvature analysis uses the 2021 Road Geometric Guidelines, assuming a curve model with the S-C-S type. After analyzing according to the planning provisions, the ideal value for the Ls length (Transitional Curve) is 60 meters, the Lc value is 39.215 meters and the ideal total length (Lt) is 159.215 meters. This shows that the condition of the existing horizontal curve has a bend length that is less than ideal when compared to the results of the analysis, namely a shortage of about 70.715 meters and a widening of the bend side of 1.104 meters is also required.

How do Paraspinal Muscles Contract during the Schroth Exercise Treatment in Patients with Adolescent Idiopathic Scoliosis (AIS)?

The Schroth exercise can train the paraspinal muscles of patients with adolescent idiopathic scoliosis (AIS), however, muscle performance during the training remains unknown. This study applied surface electromyography (sEMG) to investigate the paraspinal muscle activities before, during and after Schroth exercise in nine AIS patients. This study found that after the Schroth exercise, the paraspinal muscle symmetry index (PMSI) was significantly reduced (PMSI = 1.3), while symmetry exercise significantly lowered the PMSI (PMSI = 0.93 and 0.75), and asymmetric exercise significantly increased the PMSI (PMSI = 2.56 and 1.52) compared to relax standing (PMSI = 1.36) in participants (p < 0.05). Among the four exercises, the PMSI of on all fours (exercise 1) and kneeling on one side (exercise 3) was the most and the least close to 1, respectively. The highest root mean square (RMS) of sEMG at the concave and convex side was observed in squatting on the bar (exercise 2) and sitting with side bending (exercise 4), respectively. This study observed that the asymmetric and symmetric exercise induced more sEMG activity on the convex and concave side, respectively, and weight bearing exercise activated more paraspinal muscle contractions on both sides of the scoliotic curve in the included AIS patients. A larger patient sample size needs to be investigated in the future to validate the current observations.

Мануальная диагностика нарушений биомеханики в позвоночно-двигательных сегментах С1-С2 и С2-С3 при цервикогенной головной боли и мигрени

One of the main etiological factors of cervicogenic headache (CGH) is a violation of the biomechanics of the cervical spine (CS), mainly in the joints of the three upper cervical vertebrae (C1, C2, C3). To identify motion restriction in patients with CGH, a so-called flexion–rotation test has been proposed, which makes it possible to assess the limitation of the mobility of the atlantoaxial joint (C1-C2), which occurs on the side of the headache. Also, this test has been proposed for the differential diagnosis of CGH and migraine.&#x0D; Since the sources of CGH can be both the C1-C2 and C2-C3 joints, we proposed an alternative test – the test for lateral side bending and rotation in the C1-C2 and C2-C3 joints. During this test, the occlusion of movements in the joints below the C1-C2 spinal motion segment is achieved not by bending the neck, but by side bending in the C2-C3 joint. We used this test for both CGH and migraine.

The Importance of Lumbar Curve Flexibility and Apical Vertebral Rotation for the Prediction of Spontaneous Lumbar Curve Correction in Selective Thoracic Fusion for Lenke Type 1 and 2 C Curves: Retrospective Cohort Study with a Mean Follow-Up of More than 10 years

Study DesignRetrospective analysis of a prospectively collected data.ObjectiveLumbar flexibility(LF) is generally defined with preoperative side bending films;it is not clear what percentage of LF predicts the spontaneous lumbar curve correction (SLCC) at long term follow up. Aim of this study was to find out cut-off value of preoperative LF,apical vertebra rotation(AVR) and apical vertebral translation(AVT);which may predict more than 50%SLCC.MethodsPatients with Lenke 1C&2C curves,treated with posterior STF,with a minimum 10 years follow up were included.The patients who had more than 50% SLCC(Group A) or less than 50% (Group B) were compared in terms of LF,AVR and AVT to understand a cut-off value of those parameters.Statistically, Receiver Operating Characteristic(ROC) test was used.ResultsFifty five AIS patients (54F, 1M) with mean age 14 (11-17) were included to study.Thoracic curve correction rate was 75%;lumbar curve correction rate was 59% at the latest follow up.Group A included 45(82%) patients at the latest follow up.Three patients (5%) showed coronal decompensation at early postop and 2 of them became compensated at f/up.ROC analyses showed 69% flexibility as the cut-off value for SLCC (P < .01).The difference between groups in terms of preop mean AVRs was significant (P = .029) (Group A = 1.9; Group B = 2.4).ConclusionIn Lenke 1C&2C curves,whenever LF on the preoperative bending x-ray is greater than 70% (P < .01)and AVR is equal or less than grade 2,STF provides satisfactory clinical and radiological SLCC with more than mean 10 years f/up.This flexibility rate and apical vertebral rotation can be helpful in decision making for successful STF.

Mixed Mode Fracture Assessment for Box Girder with Crack Damage under Combined Loads

The box girder is an important structure which is widely used in the ship and marine engineering but has not extensively investigated fracture problem. The paper adopts the stress intensity factor (SIF) as the crack tip parameter to carry out the mixed mode fracture assessment of the box girder structure with crack damage. The bending load, torsion load and side load are firstly introduced to study box girder crack propagation. And the related influencing factors of crack length, crack type, combined loads, etc. are investigated emphatically. In analysis, crack growth angle is also analyzed to evaluate the crack growth. The results show that different load types have different contributions to crack propagation. And combined bending and torsion loads effect may be considered adopting a linear superposition principle under transverse cracks and larger angle cracks. When the side load is added, the area near the crack upper surface will be easy to occur unstable expansion. These conclusions will provide a guiding significance to evaluate the crack propagation of box girder.

Evaluating flexibility and predicting curve correction using fulcrum-bending radiographs in Lenke type 2 adolescent idiopathic scoliosis

BackgroundFulcrum-bending (FB) correction is considered to provide the best estimation of main thoracic (MT) curve flexibility and postoperative correction in surgical treatment for adolescent idiopathic scoliosis (AIS). However, few studies evaluated the usefulness of FB radiographs for proximal thoracic (PT) curve. We aimed to perform flexibility assessments using both active side-bending (SB) and FB radiographs and evaluate surgical outcomes after posterior spinal fusion (PSF) for Lenke type 2 AIS. MethodsThis study included 38 consecutive patients with Lenke type 2 AIS who underwent PSF using a pedicle screw construct with a minimum 2-year follow-up. Radiographic parameters, including correction rate, SB and FB flexibility, and FB correction index (FBCI: [correction rate/FB flexibility] × 100), were evaluated preoperatively, immediately after surgery, and at the 2-year follow-up. The clinical outcomes were preoperatively evaluated using the Scoliosis Research Outcomes Instrument-22 and at the follow-up. ResultsAll scoliosis curves significantly improved and shoulder balance shifted toward left shoulder elevation (all comparisons, p < 0.0001). There were significant differences between the SB and FB corrections in the PT and MT curves (p < 0.0001). The magnitudes of the discrepancies between the SB and FB corrections in the PT and MT curves were 11.2° ± 5.2° and 11.6° ± 7.2°, respectively. FB correction did not differ from postoperative Cobb angles correction immediately after surgery or at the 2-year follow-up; the mean FBCIs in the PT and MT curves were 98.8% and 105.5%, respectively. The self-image domain SRS-22 scores had significantly increased at the 2-year follow-up (p < 0.0001). ConclusionsThere were significant differences between the SB and FB corrections, and FB correction tended to approximate the postoperative curve correction (FBCI = 100%) for PT and MT curves in patients with Lenke type 2 AIS. FB flexibility is more reliable than SB flexibility in evaluating actual curve flexibility even for the PT curve.

To Compare the Effectiveness of Muscle Energy Technique and Deep Neck Flexors Training on Pain, Range of Motion and Functional Disability in Patients with Mechanical Neck Pain

The goal of this study was to examine the effectiveness of muscular energy method with deep neck flexors training on pain, range of motion, and functional impairment in individuals with mechanical neck pain. This randomized controlled trial was carried out at the Mayo Hospital's OPD physiotherapy department in Lahore. In this study, 30 patients were chosen at random and divided into two groups: Group 1 was treated with deep neck flexors training, while Group 2 was treated with muscular energy method (post isometric relaxation). Every patient signed a Performa and gave their informed permission. The questioner used to collect data was based on the NDI, Visual analogue scale (VAS), and Ranges of motion (flexion, extension, rotation, and side bending at neck). Patients in group 1 showed marked improvement as compared to group 2. Both groups showed improvement but group 1 showed statistically more improvement (p value&lt;or =to 0.05). It is concluded from the study that, patients with mechanical neck pain, when treated by deep neck flexors training showed a significant treatment outcome when analyzed on VAS, NDI, and Goniometer for ROM. When Group 1 and 2 were compared, it was seen that Group 1 showed more significant results than group 2.

Severe Lenke 1 and 2 adolescent idiopathic scoliosis had poorer perioperative outcome, higher complication rate, longer fusion and higher operative cost compared to non-severe scoliosis.

To compare the perioperative outcome and operative cost of posterior spinal fusion (PSF) surgery between severe and non-severe Lenke 1 and 2 adolescent idiopathic scoliosis (AIS) patients. A total of 509 AIS patients who underwent single-staged PSF between 2013 and 2020 were reviewed. Fifty-four severe scoliosis patients (Cobb angle ≥ 90°) were categorized into Gp1, and 455 non-severe scoliosis (Cobb angle < 90°) patients into Gp2. Propensity score matching (PSM) analysis using one-to-one nearest neighbor matching and match tolerance of 0.001 were performed. Outcome measures were operative time, intraoperative blood loss (IBL), allogeneic transfusion rate, perioperative complication, length of stay, fusion level, number of screws used, postoperative Cobb angle, correction rate (CR), side bending correction index (SBCI) and operative cost. From the PSM analysis, 35 patients from each group were matched. The operative time was 155.9 ± 41.4 and 130.0 ± 30.3min for Gp1 and Gp2, respectively (p = 0.004). The IBL was 1349.2 ± 1019.0 and 781.9 ± 325.1 mLs for Gp1 and Gp2, respectively (p = 0.003). Fusion level (12.5 ± 0.8 vs. 11.2 ± 1.3, p < 0.001) and number of screws used (16.4 ± 1.6 vs. 14.6 ± 1.4, p < 0.001) were higher in Gp1. Four perioperative complications were observed in Gp1 compared to none in Gp2 (p < 0.039). Gp1 had larger postoperative Cobb angle (p < 0.001), lower CR (p = 0.005) and higher SBCI (p < 0.001). The operative cost was higher in Gp1 (p < 0.001). Severe Lenke 1 and 2 AIS patients had poorer perioperative outcome, higher complication rate, longer fusion and higher operative cost than non-severe AIS.

EFFECT OF CARBON FIBER REINFORCED-POLYETHERETHERKETONE (CFR-PEEK) COMPOSITE ROD FOR PEDICLE SCREW-ROD SEMI-RIGID FIXATION: A FINITE ELEMENT STUDY

This study aims to evaluate the effect of pedicle screw fusion with two different rod materials on the lumbosacral spine (L1-S). Three-dimensional geometry of the L1-S spine is developed using computed tomography images and two levels of screw-rod fusion having two different rods, titanium alloy (Ti-6Al-4V) and carbon fiber-reinforced polyetherether-ketone (CFR-PEEK). The finite element simulations are done for the implanted models as well as intact models under different physiological conditions, such as clockwise rotation, counterclockwise rotation, right side bending, left side bending, flexion, and extension under the moments of 2-10 nm with an increment of 2 nm. For a pedicle screw rod with Ti-6Al-4V, a very low value of the range of motion (ROM) is observed, 1.3 deg for extension and 1.9 deg for flexion during a 10 nm moment. For the CFR-PEEK rod, the ROM is improved by 3.2-4, 4-6.5, and 1.9-2 times under rotation, side bending, and flexion-extension, respectively, compared to Ti-6Al-4V rod fixation. The implanted region with Ti-6Al-4V rods resists the ROM, which is undesirable and affects the kinematics of the spine. Thus, the ROM at the implanted segments can be increased by using CFR-PEEK rod materials, which have very low stiffness.

Parametric study of stress distribution in bimodular curved beam

This paper uses classical beam theory for stress analysis of bimodular material straight and curved beams. Hamilton’s principle is used to obtain the equations of motion. The stiffness parameters are calculated using equivalent stiffness methods to consider various couplings (twisting-stretching, bending-twisting coupling), and the neutral surface position is calculated by the Newton-Raphson method. Through the thickness, normal stress distributions are presented for different stacking sequences, the radius of curvature, and bimodularity ratio for simply supported boundary conditions. It is observed that, unlike unimodular materials, stress distribution for bimodular materials is different in positive and negative side bending. The parametric study showed that the increment of bimodularity ratio increases the magnitude of stress in the tensile zone but decreases in the compressive zone. The effects of couplings are more in angle-ply compared to mixed-ply and cross-ply laminates.

Physical Therapy and Migraines

Migraine is a most common type of headache that has been seen in almost every age group. This is the chemical imbalance within the brain causing substantial disability and pain. It is usually a pulsating sensation or a throbbing pain at one side of head. The main symptoms of migraine headache along with pain are nausea, vomiting, photosensitivity and extreme sensitivity to sounds. Lethargy in the body and tightness in the muscles around the head has also been seen. It involves almost 4 stages including prodrome, aura, migraine and postdrome lasting from one day to sometimes a week. But this is more common for one or two days. Dehydration, direct sunlight, skipping meals, hunger and stress sometimes may aggravate the migraines. Stress induced migraines are of extreme importance as it affects the muscles such as trapezius, sternocleidomastoid, levator scapulae and facial muscles due to pressure hypersensitivity.&#x0D; This is a neurological disorder but physical therapy may help in population with migraine. Some techniques could be quite useful such as:&#x0D; &#x0D; Soft tissue release&#x0D; Posterior-anterior cervical joints mobilization&#x0D; Upper cervical spine manipulation&#x0D; Needling therapy in the affected muscles&#x0D; Therapeutic exercises&#x0D; &#x0D; Soft tissue release technique may involve myofacsial trigger points release in the trapezius and sternocleidomastoid muscles as these get the tightness allover. Manual stroking by addressing the muscles and stroking away the trigger point from the center. Tender point release has also its utmost importance for releasing the migraines. Interestingly, by releasing the muscles over temporomandibular joint can reduce the migraine pain&#x0D; Posterior-anterior approach for upper cervical mobilization should be used for C1-C3. In this approach the thumbs of therapist glide over the zygophageal joints posterior-anteriorly. Upper cervical spine manipulations is applied by localizing the target area in the rotation position and then perform a low amplitude and high velocity thrust towards the contralateral eye of the patient. Spinal mobilization and manipulation actually targets the musculoskeletal disorders caused by the migraines. It directly cannot lessen the migraine but may aid to reduce it by relaxing the muscles. &#x0D; Therapeutic exercise may affect the pain positively by releasing the pressure such as cervical flexion; side bending and lateral flexion are some of the types of cervical isometrics may help to lessen the pain. This basically targets the deep neck muscles that can only be approached through therapeutic exercises. These fore mentioned techniques may help to reduce the migraine pains.

Range of motion in upper and lower Cervical spine in Dentists with chronic Neck pain of Lahore city

Neck pain is a commonly reported problem these days mostly due to increased screen timings and mobile usage, other than age factors Objective:To check range of motion in upper and lower cervical spine in dentists with chronic neck painMethods:cross-sectional Study was conducted and non-probability convenient sampling technique was used to get sample size. Forty-three participants were taken in this study. Only dentists with chronic neck pain were included. Association between pain intensity and cervical range of motion was obtained. After taking consent information data was collected by using cervical range of motion device and neck disability index questioner. Data was analyzedusing SPSS21Results:There was association between pain intensity and cervical flexion (p-value=0.043), pain intensity and cervical bending left side (p-value=0.000) while there was no association between pain intensity and cervical extension (p-value=0.201), pain intensity and cervical bending Right side (p-value=0.721), pain intensity and cervical rotation right side (p-value=0.207),pain intensity and cervical rotation left side (p-value=0.178)Conclusions:Dentists with chronic neck pain have decreased cervical flexion, cervical left side bending due to bad standing posture and continuous flexed neck for longer duration during work.

Evaluation of a Chair-Mounted Passive Trunk Orthosis: A Pilot Study on Able-Bodied Subjects

Trunk stability is important for adequate arm function due to their kinematic linkage. People with Duchenne muscular dystrophy (DMD) can benefit from trunk-assistive devices for seated daily activities, but existing devices limit trunk movement to forward bending. We developed a new trunk orthosis that has spring and pulley design. This study evaluated orthosis performance with 40 able-bodied subjects under with and without orthosis condition in 20 seated tasks for trunk rotation, forward bending, and side bending movements. Subjects adopted static posture in specific trunk orientation while their muscle activity was recorded. They also rated the subjective scales of perceived exertion and usability. A percent change in muscle activity for each task, due to orthosis use, is reported. Significant muscle activity reductions up to 31% and 65% were observed in lumbar and thoracic erector spinae muscles, respectively. Using three-way ANOVA, we found these reductions to be specific to the task direction and the choice of upper limb that is used to perform the asymmetric tasks. A total of 70% participants reported acceptable usability and ~1-point increase in exertion was found for maximum voluntary reaching with the orthosis. The outcomes of this study are promising, though tested on able-bodied subjects. Hence, orthosis mounted on wheelchairs should be further evaluated on DMD patients.

SHAFT LOADS ON AZIMUTH PROPULSORS IN OBLIQUE FLOW AND WAVES

A range of model experiments have been carried out in calm water and waves for an oil spill vessel model with twin tractor azimuth thrusters at different heading angles and advance coefficients in the large towing tank at the Marine Technology Centre in Trondheim, Norway. Propeller shaft bending loads have been measured using a shaft dynamometer capable of measuring all shaft side force and bending moment components as well as propeller torque and thrust. The results include the loads on the propeller shaft with and without the presence of a ship hull model at the same heading angles and advance velocities in order to study the wake influence from the ship hull on the hydrodynamic loads. Results show that the ship hull wake has a much stronger effect on the propeller loads when the propeller is azimuthed outward from the ship hull centreline than inward. Measurements from the experiments in waves are also presented for the same thruster model in a straight-line course for both the head and following sea states under different wave conditions. Larger bending loads are found in head sea conditions compared with the following sea conditions. Generally it is found that the shaft bending loads and lateral forces are quite large, which is important to consider in the mechanical design layout and for dimensioning of components.

Bioresorbable plate fracture after cranioplasty caused by head injury: a pediatric case

BackgroundRecently, bone fixation materials have been developed as surgical materials. Bioabsorbable materials offer several advantages over other materials and are widely used. We report a rare case of the fracture of bioresorbable plates caused by head injury and describe some considerations.Case descriptionA 6-year-old boy suffered from consciousness disturbance. He was admitted to our hospital and diagnosed with left frontal subcortical hemorrhage due to ruptured arteriovenous malformation (AVM). He received the surgery of removal of the AVM with decompressive craniectomy. He was discharged without any neurologic deficit and underwent the cranioplasty 4 months after the initial surgery. Two months after the last treatment, he was fallen and hit his left frontal head. The next day, he noticed an abnormal bulge in the injured area. We diagnosed the bulging as cerebrospinal fluid leakage because of the dural tear. The repairment of dural tear was performed. We found that two bioresorbable plates used by cranioplasty were both cracked, and the dura mater beneath them was torn. We repaired the damaged dura with an artificial dura mater. After surgery, cerebrospinal fluid leakage did not occur.ConclusionIt has been reported that the durability of bioresorbable plates is no less than that of titanium plates. We experienced a relatively rare case in which bioabsorbable plate used for bone fixation was damaged due to head trauma. After craniotomy or cranioplasty using bioresorbable plates, special attention should be paid to head trauma that involves bone flap sinking force and side bending stress.