SU(1,1) symmetry of multimode squeezed states

We show that a class of multimode optical transformations that employ linear optics plus two-mode squeezing can be expressed as SU(1,1) operators. These operations are relevant to state-of-the-art continuous variable quantum information experiments including quantum state sharing, quantum teleportation, and multipartite entangled states. Using this SU(1,1) description of these transformations, we obtain a new basis for such transformations that lies in a useful representation of this group and lies outside the often-used restriction to Gaussian states. We analyze this basis, show its application to a class of transformations, and discuss its extension to more general quantum optical networks

Comparison of invertor and evertor muscle strength in patients with chronic functional ankle instability

In this study we tried to measure Invertor and Evertor muscles strength with Isokinetic dynamometer to distinguish, if these muscles activate properly or not. Thirty subjects (15 healthy and 15 patients with chronic functional ankle Instability (CFAI) aged 18-30 years) participated in this study. Maximum eccentric and concentric peak Torque of invertor and evertor muscles measured with Biodex system in 2 different speeds, 60 and 120 degree per second. Statistical analysis showed that maximum eccentric peak torque of invertor muscles in both 60 and 120 degree per second differed statistical significance between two groups, as in the patients group was less than normal subjects (p<0.05). It means that eccentric weakness of invertor muscles will lead to CFAI

Dangling-bond charge qubit on a silicon surface

Two closely spaced dangling bonds positioned on a silicon surface and sharing an excess electron are revealed to be a strong candidate for a charge qubit. Based on our study of the coherent dynamics of this qubit, its extremely high tunneling rate ~ 10^14 1/s greatly exceeds the expected decoherence rates for a silicon-based system, thereby overcoming a critical obstacle of charge qubit quantum computing. We investigate possible configurations of dangling bond qubits for quantum computing devices. A first-order analysis of coherent dynamics of dangling bonds shows promise in this respect.Comment: 17 pages, 3 EPS figures, 1 tabl

Effects of Lateral Wedge Insole on Static and Dynamic Balance in Patients with Moderate Medial Knee Osteoarthritis

BACKGROUND AND OBJECTIVE: Knee osteoarthritis (OA) is associated with diminished joint proprioception, balance deficits and increased risk of falls. Patients with medial knee osteoarthritis are at higher risk of balance deficits and falling due to the development of secondary varus deformity. Therefore, it is of great clinical importance to identify the treatment methods that could improve balance in knee OA. The purpose of this study was to evaluate the effects of Lateral Wedge Insole (LWI) on static and dynamic balance in patients with moderate medial knee osteoarthritis. METHODS: Thirty patients with moderate medial knee OA participated in this semi-experimental interventional study. Patients were recruited from orthopedic and rheumatology clinics of the university. For each patient, the static and dynamic balance were assessed in two conditions including wearing shoes with flat insole and wearing shoes with lateral wedge insole, using a Prokin stabilometer. The balance variables were the anteroposterior and mediolateral velocity and standard deviation of the center of pressure (COP) displacement, and total stability indices. Patients performed two familiarization trials, then, three actual trials with at least 30 s interval for each test. FINDINGS: Wearing LWIs resulted in significant decreases in the anteroposterior (static:1.78mm/s, dynamic:6.63mm/s) and mediolateral velocity of COP (static:1.53mm/s, dynamic:5.58mm/s) in compression to wearing shoes with flat insole (p<0.001). The anteroposterior (static:1.04 mm, dynamic:1.57mm) and mediolateral SD of the COP (static:1.58mm, dynamic:2.02mm) were also decreased after using LWIs (p<0.007). Except for the anteroposterior stability index, other balance indices were also significantly improved (p<0.05). CONCLUSION: Our findings suggest that using a LWI improve static and dynamic balance in patients with moderate medial knee OA

Normalized Electromyography of Shoulder Muscles during Selected Functional Tasks of Upper Limb in Patients with Shoulder Impingement Syndrome

Abstract: Background & Aims: Precise muscle activity pattern is required to maintain normal shoulder function and any alteration in muscle activity can result in movement impairment. The purpose of this study was to assess normalized electromyography (EMG) of shoulder muscles during selected functional tasks of upper limb in patients with shoulder impingement syndrome. Methods: Test group consisted of 15 subjects with shoulder impingement syndrome selected by nonprobability convenient sampling and control group consisted of 15 matched healthy subjects. In each group selected exercises including open kinetic chain with and without external load and closed kinetic chain with axial load were done and during each exercise surface EMG from selected muscle was recorded. Results: There was significant difference between the two groups in the activities of upper trapezius, infraspinatus and three regions of deltoid muscle (P2E showed minimum changes and tripod showed maximum changes in muscle activity domain. Conclusion: Decrease in activity domain of infraspinatus and trapezius muscles in patients with shoulder impingement syndrome causes impairment of shoulder function. D2E with causing minimum changes and Tripod with causing maximum changes in muscles activity domain are suggested respectively as the first and the last activity patterns in the treatment of these patients. Keywords: Shoulder joint, Shoulder impingement syndrome, Electromyography, Exercise, Biomechanic

Comparative study of forward walking and running with backward walking and running on lower limbs function

History and Objectives: The ultimate objective of rehabilitation in sport injury is the rapid and safe return of the individual to his pre-injury status. If the therapeutic plan is oriented only to increase strength, tolerance and range of motion and such factors as balance, agility, deep sensation and neuromuscular coordination are not stressed the risk of repeated injury will increase. In this study the effect of walking and running as the main function of lower limbs are considered. Materials and Methods: This study has been carried out as a clinical trial using six functional performance tests of single leg hop distance test, vertical jump, anaerobic power test, modified Romberg test, shuttle run and single leg hop for time before and after exercise in two groups of 15 healthy girls matched for age. All the girls had three sessions of 15 minutes running forward and background each week for six consecutive weeks. At the end of each week, some of the tests were performed and finally after eight weeks, all the tests were repeated again. Results: In the group walking or running forward, vertical test revealed 0.46% (P>0.003), single leg hop for time 10.52% (P>0.005), vertical jump 9.95% (P>0.005), anaerobic power 4.58% (P>0.005), modified Romberg test 59.26% (P>0.003) and shuttle run test 2.19% (P>0.001) improvement and for those with backward walking or running, single leg hop distance test revealed 4.5% (P>0.003), single leg hop for time 23.89% (P0.005), anaerobic power test 0.53% (P>0.005), modified Romberg test 68.33% (P>0.003) and shuttle run test 6.88% (P<0.001) improvement. Conclusion: In rehabilitation planning, when improvement of strength, velocity, agility, static balance and aerobic power is considered, walking and running backwards and when increase in vertical jump, or aerobic power is the aim, walking and running forward is recommended

Traditional physical therapy exercises combined with sensorimotor training: The effects on clinical outcomes for chronic neck pain in a double-blind, randomized controlled trial

Objective: This study examined the effects of combining traditional physical therapy exercises with sensorimotor training on joint position sense, pain, muscle endurance, balance and disability in patients with chronic, non-specific neck pain. Design: Double-blind, randomized controlled trial. Subjects: A total of 53 patients with chronic non-specific neck pain were randomized to either traditional or combined exercise groups. Interventions: All patients received 12 sessions of supervised intervention 3 times per week. The traditional group performed traditional exercises, and the combined exercise group performed sensorimotor training in addition to traditional exercises. Outcome measures: Joint position sense, pain, neck flexor muscle endurance test, 10 Meter Walk Test, step test, and the Neck Disability Index. Results: The combined exercise group showed significantly greater improvement compared to the traditional group in joint position sense during extension, flexion, right rotation, the 10 m walk test with head turn, and the step test. Pain intensity, muscle endurance, and disability improved in both groups. Additionally, there was a higher degree of effect on muscle endurance in the combined exercise group compared to a moderate effect in the traditional group. Conclusions: A combination of sensorimotor training with traditional physical therapy exercises could be more effective than traditional exercises alone in improving joint position sense, endurance, dynamic balance and walking speed. © 201

Cervical movement kinematic analysis in patients with chronic neck pain: A comparative study with healthy subjects

Background: Several studies have investigated cervical kinematic performance in patients with chronic neck pain, especially with fast movements. A recent systematic review recommended further study of cervical spine kinematics cervical motions in individuals with neck pain. Objectives: This study aimed to examine cervical spine kinematics of naturally paced cervical motions in patients with chronic neck pain compared with a group of asymptomatic participants. Also, the relationships between cervical kinematic measures with neck pain intensity and disability were determined. Method: Kinematic performance was measured in 20 individuals with chronic nonspecific neck pain and 20 healthy controls. Data were captured using a 7-camera motion analysis system. Parameters were range of cervical motion, peak velocity, duration of movement, and jerk index (smoothness of movement). Pain intensity and Neck Disability Index were also measured. Results: Duration of movements, peak velocities, and jerk indexes were significantly different between the two groups (p < 0.05). Pain intensity was significantly associated with duration of movement, range of motion, peak velocity, and smoothness predominantly in extension (r range = 0.4 to 0.6, p < 0.05). Conclusion: This study's findings indicated altered cervical kinematic performance during naturally paced motions (particularly reduced smoothness of movement)in patients with chronic nonspecific neck pain compared to asymptomatic participants. Also, pain intensity was moderately associated with most kinematic measures, especially in extension. This study's results can help to understand better the impairments associated with chronic nonspecific neck pain. © 202

Muscle Activity Pattern Dysfunction During Sit to Stand and Stand to Sit in the Movement System Impairment Subgroups of Low Back Pain

Objective: To investigate impairment in the activity pattern of some muscles involved in sit to stand (STD) and stand to sit (STS) among 2 low back pain (LBP) subgroups of the Movement System Impairment (MSI) model. Design: Case-control study. Setting: A university medical center. Participants: Fifteen women without chronic LBP and 22 women with chronic LBP (N=37) in 2 subgroups (15 into the lumbar extension rotation (LER) and 7 into lumbar flexion rotation LFR) voluntarily participated in this study. Interventions: Participants were asked to perform STD and STS at a preferred speed. Surface electromyography (EMG) were measured bilaterally from the internal oblique (IO), lumbar erector spine (ES), medial hamstring (MH), and lateral hamstring (LH) muscles. Main Outcome Measures: Changes in mean and maximum amplitude, time to peak amplitude, duration of muscle activity, and bilateral asymmetry of these variables. Results: During STD, bilateral asymmetry in mean amplitude of MH in the LER subgroup (P=.031) and bilateral asymmetry in duration of LH in the LFR subgroup (P=.026) were exhibited. Also, in this task reduced time to peak left MH activation were found in the LFR subgroup than 2 other groups (control; P=.028/LER; P=.004). During STS, increased left ES maximum amplitude were observed in the LFR subgroup than LER subgroup (P=.029). Also, reduced time to peak right ES (P=.035) and left LH (P=.038) activation in the LER subgroup than control subjects and reduced time to peak left LH activation in LFR subgroup than control subjects (P=.041) were observed during STS. Conclusions: The differences between the 2 LBP subgroups may be a result of impairment in the activity pattern of some muscles during functional activity. © 2018 American Congress of Rehabilitation Medicin

Effects of Virtual Reality vs Conventional Balance Training on Balance and Falls in People With Multiple Sclerosis: A Randomized Controlled Trial

Objective: To assess the efficacy of virtual reality (VR)-based vs conventional balance training on the improvement of balance and reduction of falls in people with multiple sclerosis (PwMS). Design: Single-blinded, randomized, controlled trial. Setting: Musculoskeletal Rehabilitation Research Center, Ahvaz Jundishapur University of Medical Sciences. Participants: PwMS (N=39), randomized into VR (n=19) and control (n=20) groups. Intervention: The VR group performed exergames using Kinect, while the control group accomplished conventional balance exercises. Both groups received 18 training sessions for 6 weeks. Main Outcome Measures: Limits of stability, timed Up and Go (TUG) test, and 10-m walk tests with and without cognitive task and their dual-task costs (DTCs), Berg Balance Scale, Multiple Sclerosis Walking Scale-12, Fall Efficacy Scale-International, Activities-specific Balance Confidence Scale, and fall history were obtained pre- and post intervention and after a 3-month follow-up. Results: At both post intervention and follow-up, TUGcognitive and DTCs on the TUG were significantly lower and the 10-m walkcognitive was significantly higher in the VR group. At follow-up, reaction time and the number of falls demonstrated significant differences favoring the VR group, whereas the directional control revealed significant difference in favor of the control group (P&lt;.05). The other outcomes showed no statistically significant difference at post intervention or follow-up. Conclusions: Both the VR-based and conventional balance exercises improved balance and mobility in PwMS, while each acted better in improving certain aspects. VR-based training was more efficacious in enhancing cognitive-motor function and reducing falls, whereas conventional exercises led to better directional control. Further studies are needed to confirm the effectiveness of recruiting VR-based exercises in clinical settings. © 2020 American Congress of Rehabilitation Medicin