Time-Resolved PIV Measurements and Turbulence Characteristics of Flow Inside an Open-Cell Metal Foam.

Open-cell metal foams are porous medium for thermo-fluidic systems. However, their complex geometry makes it difficult to perform time-resolved (TR) measurements inside them. In this study, a TR particle image velocimetry (PIV) method is introduced for use inside open-cell metal foam structures. Stereolithography 3D printing methods and conventional post-processing methods cannot be applied to metal foam structures; therefore, PolyJet 3D printing and post-processing methods were employed to fabricate a transparent metal foam replica. The key to obtaining acceptable transparency in this method is the complete removal of the support material from the printing surfaces. The flow characteristics inside a 10-pore-per-inch (PPI) metal foam were analyzed in which porosity is 0.92 while laminar flow condition is applied to inlet. The flow inside the foam replica is randomly divided and combined by the interconnected pore network. Robust crosswise motion occurs inside foam with approximately 23% bulk speed. Strong influence on transverse motion by metal foam is evident. In addition, span-wise vorticity evolution is similar to the integral time length scale of the stream-wise center plane. The span-wise vorticity fluctuation through the foam arrangement is presented. It is believed that this turbulent characteristic is caused by the interaction of jets that have different flow directions inside the metal foam structure. The finite-time Lyapunov exponent method is employed to visualize the vortex ridges. Fluctuating attracting and repelling material lines are expected to enhance the heat and mass transfer. The results presented in this study could be useful for understanding the flow characteristics inside metal foams.

Ultrasound Imaging of the Trunk Muscles in Acute Stroke Patients and Relations With Balance Scales.

OBJECTIVE: To examine the correlation between ultrasonographic trunk muscle parameters and balance scales in mild acute stroke patients. METHODS: A total of 55 stroke patients with hemiparesis and motor power grade ≥4 in the manual motor test were included. The Scale for the Assessment and Rating of Ataxia (SARA), Berg Balance Scale (BBS), Timed Up and Go Test (TUG), and Trunk Control Test (TCT) were used to evaluate patient balance function. Ultrasonographic parameters were measured on both non-paretic and paretic sides of the rectus abdominis, external oblique, internal oblique, transversus abdominis, and erector spinae muscles. Resting thickness and contraction thickness were measured in all muscles, and contractility and contractility ratio were calculated based on measured thicknesses. The differences between paretic and non-paretic muscle parameters, and the correlation between ultrasonographic parameters and balance scales were analyzed. Stroke patients were divided into two groups according to their fall risk. Ultrasonographic measurements between the two groups were compared. RESULTS: All muscles' contraction thickness and contractility were significantly different between paretic and non-paretic sides (p<0.001). Contractility ratios of all trunk muscles showed a significant correlation with SARA, BBS, TUG, and TCT (p<0.05). Contractility ratios of all muscles were significantly different between high- and low-risk fall groups (p<0.05). CONCLUSION: The contractility ratio in stroke patients reflects their balance disturbance and fall risk and it may serve as a new parameter for ultrasound imaging of trunk muscles.

Evaluation of Ataxia in Mild Ischemic Stroke Patients Using the Scale for the Assessment and Rating of Ataxia (SARA).

OBJECTIVE: To demonstrate the utility of Scale for the Assessment and Rating of Ataxia (SARA) for evaluation of posterior circulation-related features in patients with mild stroke. METHODS: Forty-five subjects, diagnosed with acute infarction in the cerebellum, basis pontis, thalamus, corona radiata, posterior limb of internal capsule, and their National Institutes of Health Stroke Scale (NIHSS) scores ≤5 were enrolled. SARA scores were graded by the cut-off value of severity in dependency of activities of daily living (ADL). SARA, Berg Balance Scale (BBS), Timed Up-and-Go (TUG), and Trunk Control Test (TCT) were correlated in regression analysis with the modified Rankin Scale (mRS) at discharge. Correlation between SARA and other tools was analyzed. Patients were divided based on mRS at admission (group A, mRS 0-2; group B, mRS 3-5). Scores between the two groups were compared. RESULTS: Among the subjects, 48.9% (22/45) scored above 5.5 on SARA, and even 11.1% (5/45) scored higher than 14.25, which is the cut-off value of 'severe dependency' in ADL. SARA showed significant value for prediction of mRS at discharge. SARA was correlated with BBS (r=-0.946, p<0.001), TUG (r=-0.584, p<0.001), and TCT (r=-0.799, p<0.001). The SARA, BBS, TUG, and TCT scores between were lower in group B than in group A patients. SARA as well as BBS, TUG, and TCT reflect the functional severity of all patients. CONCLUSION: SARA is a complementary tool for evaluation of the severity of ataxia in mild stroke patients with features of posterior circulation.

Effects of resistance expiratory muscle strength training in elderly patients with dysphagic stroke.

BACKGROUND: Recently, resistance expiratory muscle strength training (EMST) has been reported as a remedial treatment for dysphagia. OBJECTIVE: To investigate the effect of resistance EMST on the swallowing function in stroke patients with oropharyngeal dysphagia. METHODS: Forty-two stroke patients with dysphagia were randomly assigned to two groups: an experimental group (n = 13) and a placebo group (n = 13). The experimental group performed EMST using a portable EMST device, while the placebo group performed EMST using a sham EMST device with no loading. The intervention was performed 5 days per week for 4weeks, in five sets of 5 breaths through the device for a total of 25 breaths per day. Both groups underwent conventional dysphagia treatment for 30 minutes/day, 5 days/week, for 4 weeks. Videofluoroscopic dysphagia scale (VDS) and penetration-aspiration scale (PAS) based on a videofluoroscopic swallowing study (VFSS) were assessed to analyze the oropharyngeal swallowing function. RESULTS: The experimental group showed more improvement in pharyngeal phase of the VDS (p = 0.018 and 0.006, respectively) and PAS compared to the placebo group (p = 0.014). CONCLUSIONS: We suggest that EMST could improve the effects of dysphagia observed in post-stroke elderly patients based on swallowing function.

Characteristics of pulsatile flows in curved stenosed channels.

Spatial and temporal variations of the hemodynamic features occur under pulsatile conditions in complex vessel geometry. Wall shear stress affected by the disturbed flow can result in endothelial cell dysfunction, which leads to atherogenesis and thrombosis. Therefore, detailed understanding of the hemodynamic characteristics in a curved stenosed channel is highly important when examining the pathological effects of hemodynamic phenomena on the progression of atherosclerosis. The present study measures the velocity fields of pulsatile flows with three different Reynolds numbers in 3D curved vessel models with stenosis using time-resolved particle image velocimetry (PIV). Three different models were cast in PDMS polymer using models made by a 3D printer with different bend angles of 0°, 10°, and 20° between the longitudinal axes at the upstream and downstream of the stenosis. To investigate the 3D flow structures, a stack of 2D velocity fields was obtained by adjusting the position of the laser sheet along the Z-direction. The structures of flow fields in the stenosed models were analyzed using the distribution of the shearing strain as well as the skewness and full width at half maximum of the velocity profile. To support experiment results, distributions of pressure and 3D vortex in the curved stenosed channels were estimated by conducting the numerical simulation. These results indicate that the curvature of the tube considerably influences the skewness of the flow, and the shear stress is intensified near the outer curvature wall due to centrifugal force. The results would be helpful in understanding the effects of geometrical factors on plaque rupture and severe cardiovascular diseases.

Effects of Shaker exercise in stroke survivors with oropharyngeal dysphagia.

BACKGROUND: Dysphagia after stroke can cause a variety of complications, especially aspiration pneumonia, which can be life-threatening. Therefore, rehabilitation methods to reduce aspiration in patients with dysphagia are important. OBJECTIVE: In the present study, we aimed to investigate the effects of Shaker exercise on aspiration and oral diet level in stroke survivors with dysphagia. METHODS: Participants were randomly assigned to an experimental group (n = 16) or a control group (n = 16). Participants in the experimental group performed Shaker exercise and conventional dysphagia therapy, whereas those in the control group performed only conventional dysphagia therapy. All participants performed training 5 days a week for 4 weeks. Degree of aspiration was assessed using the Penetration-Aspiration Scale (PAS) based on videofluoroscopic swallowing study, while oral diet level was assessed using the Functional Oral Intake Scale (FOIS). RESULTS: The experimental group showed greater improvement on both the PAS (p < 0.05) and FOIS (p < 0.05) compared with the control group. CONCLUSIONS: The results of this study suggest that Shaker exercise is a effective exercise for recovery of swallowing function in stroke survivors with dysphagia.

Acute Cerebral Infarction as a Rare Thrombotic Event in Myelodysplastic Syndrome: A Case Report.

Myelodysplastic syndrome (MDS) is a bone marrow failure syndrome characterized by cytopenia that results in high risks of infection and bleeding. However, there are few reports of cerebral infarction in MDS. We reported a 72-year-old female with MDS who developed acute cerebral infarction. Clinical history of the patient revealed no definite risk factors for stroke except diabetes mellitus and dyslipidemia that was well controlled. This case represented the rare occurrence of arterial thrombosis causing acute cerebral infarction in MDS, which may be due to complex chromosomal abnormality and inflammatory processes.

Analysis of Vertical Ground Reaction Force Variables Using Foot Scans in Hemiplegic Patients.

OBJECTIVE: To analyze the differences in the vertical ground reaction force (GRF) variables of hemiplegic patients compared with a control group, and between the affected and unaffected limbs of hemiplegic patients using foot scans. METHODS: Patients (n=20) with hemiplegia and healthy volunteers (n=20) underwent vertical force analysis. We measured the following: the first and second peak forces (F1, F2) and the percent stances at which they occurred (T1, T2); the vertical force impulse (VFI) and stance times. The GRF results were compared between the hemiplegic patients and control individuals, and between the affected and unaffected limbs of hemiplegic patients. Additionally, we analyzed the impulse of the unaffected limb according to the motor assessment scale (MAS), Brunnstrom stage, and a Timed Up and Go Test. RESULTS: The F1s and F2s of the affected and unaffected limbs were significantly less than those of the normal control individuals (p<0.05). The T1s of both the affected and unaffected limbs of the patients were greater than control individuals, whilst the T2s were lower (p<0.05). Greater impulses and stance times were recorded on both sides of the patients than in the limbs of the control individuals (p<0.05). The MAS, Brunnstrom stage and Timed Up and Go Test results were significantly correlated with the VFI of the unaffected limbs (p<0.05). CONCLUSION: The high impulse values of the unaffected limb were associated with complications during gait rehabilitation. Therefore, these results suggest that unaffected limbs should also be taken into consideration in these patients.

Changes in Activation of Abdominal Muscles at Selected Angles During Trunk Exercise by Using Ultrasonography.

OBJECTIVE: To investigate the changes of activation of the abdominal muscles depending on exercise angles and whether the activation of rectus abdominis differs according to the location, during curl up and leg raise exercises, by measuring the thickness ratio of abdominal muscles using ultrasonography. METHODS: We examined 30 normal adults without musculoskeletal problems. Muscle thickness was measured in the upper rectus abdominis (URA), lower rectus abdominis (LRA), obliquus externus (EO), obliquus internus (IO), and transversus abdominis (TrA), at pre-determined angles (30°, 60°, 90°) and additionally at the resting angle (0°). Muscle thickness ratio was calculated by dividing the resting (0°) thickness for each angle, and was used as reflection of muscle activity. RESULTS: The muscle thickness ratio was significantly different depending on the angles in URA and LRA. For curl up-URA p=0 (30°<60°), p=0 (60°>90°), p=0.44 (30°<90°) and LRA p=0.01 (30°<60°), p=0 (60°>90°), p=0.44 (30°>90°), respectively, by one-way ANOVA test-and for leg raise-URA p=0 (30°<60°), p=0 (60°<90°), p=0 (30°<90°) and LRA p=0.01 (30°<60°), p=0 (60°<90°), p=0 (30°<90°), respectively, by one-way ANOVA test-exercises, but not in the lateral abdominal muscles (EO, IO, and TrA). Also, there was no significant difference in the muscle thickness ratio of URA and LRA during both exercises. In the aspect of muscle activity, there was significant difference in the activation of RA muscle by selected angles, but not according to location during both exercises. CONCLUSION: According to this study, exercise angle is thought to be an important contributing factor for strengthening of RA muscle; however, both the exercises are thought to have no property of strengthening RA muscle selectively based on the location.

Ultrasonographic measurement of transverse abdominis in stroke patients.

OBJECTIVE: To compare transverse abdominis (TrA) contractility in stroke patients with hemiparesis and healthy adults using musculoskeletal ultrasonography. METHODS: Forty-seven stroke patients with hemiparesis and 25 age-matched healthy control subjects participated in this study. Stroke patients were divided into three groups on the basis of their degree of ambulation. Group A consisted of 9 patients with wheelchair ambulation, group B of 23 patients with assisted ambulation, and group C of 15 patients with independent ambulation. Inter-rater reliability regarding ultrasonographic measurement of abdominal muscle thickness in the control group was assessed by two examiners. The TrA contraction ratio (TrA contracted thickness/TrA resting thickness) was measured during abdominal drawing-in maneuver and was compared between the patients and the control group and between the ambulation groups. RESULTS: The inter-rater reliability ranged from 0.900 to 0.947. The TrA contraction ratio was higher in the non-paretic side than in the paretic side (1.40±0.62 vs. 1.14±0.35, p<0.01). The TrA contraction ratio of the patient group was lower in the non-paretic side as well as in the paretic side than that of the control group (right 1.85±0.29, left 1.92±0.42; p<0.001). No difference was found between the ambulation regarding the TrA contraction ratio. CONCLUSION: The TrA contractility in hemiparetic stroke patients is significantly decreased in the non-paretic side as well as in the paretic side compared with that of healthy adults. Ultrasonographic measurement can be clinically used in the evaluation of deep abdominal muscles in stroke patients.

Efficacy of kinesiology taping for recovery of dominant upper back pain in female sedentary worker having a rounded shoulder posture.

BACKGROUND: Sedentary workers are most prone to work-related musculoskeletal disorders. OBJECTIVE: We report the case of a female sedentary worker with rounded shoulder posture (RSP) whose dominant upper back pain decreased after correction of her RSP with kinesiology taping. METHODS: We applied kinesiology taping around the patient's upper back and shoulder for 1 month (six times per week, each session lasting approximately 16 h) without any other interventions. RESULTS: After kinesiology taping, the RSP decreased progressively and the dominant upper back pain gradually disappeared. The patient no longer complained of dominant upper back pain during desk work. CONCLUSION: We believe that kinesiology taping may be used to enable recovery from dominant upper back pain in female sedentary workers with RSP.

Effect of silane activation on shear bond strength of fiber-reinforced composite post to resin cement.

PURPOSE: Among the surface treatment methods suggested to enhance the adhesion of resin cement to fiber-reinforced composite posts, conflicting results have been obtained with silanization. In this study, the effects of silanization, heat activation after silanization, on the bond strength between fiber-reinforced composite post and resin cement were determined. MATERIALS AND METHODS: Six groups (n=7) were established to evaluate two types of fiber post (FRC Postec Plus, D.T. Light Post) and three surface treatments (no treatment; air drying; drying at 38℃). Every specimen were bonded with dual-curing resin cement (Variolink N) and stored in distilled water for 24 hours at 37℃. Shear-bond strength (MPa) between the fiber post and the resin cement were measured using universal testing device. The data were analyzed with 1-way ANOVA and by multiple comparisons according to Tukey's HSD (α=0.05). The effect of surface treatment, fiber post type, and the interactions between these two factors were analyzed using 2-way ANOVA and independent sample T-tests. RESULTS: Silanization of the FRC Postec Plus significantly increased bond strength compared with the respective non-treated control, whereas no effect was determined for the D.T. Light Post. Heat drying the silane coupling agent on to the fiber-reinforced post did not significantly improve bond strength compared to air-syringe drying. CONCLUSION: The bond strength between the fiber-reinforced post and the resin cement was significantly increased with silanization in regards to the FRC Postec Plus post. Bond strength was not significantly improved by heat activation of the silane coupling agent.

Proteomic changes in rat gastrocnemius muscle after botulinum toxin a injection.

OBJECTIVE: To observe the changes in protein expression induced by botulinum toxin A (BoNT-A) injection and to characterize the molecular and cellular action of mechanisms of BoNT-A injection on skeletal muscles using proteomic elements as biomarkers. METHODS: BoNT-A was injected into left gastrocnemius muscles of 12 Sprague-Dawley rats (2 months of age) at a dosage of 5 units/kg body weight. For the controls same volume of normal saline was injected to right gastrocnemius muscle of each rat. Muscle samples were obtained at 4 time points (3 rats per time point): 3, 7, 14, and 56 day post-injection. To reveal the alterations in muscle protein, we performed 2-dimensional electrophoresis (2DE) and compared Botox group and normal saline group at each time point. Altered protein spots in 2DE were identified using matrix-assisted laser desorption/ionization-time-of-flight mass spectrometer (MALDI-TOF MS) proteomics analysis. RESULTS: Compared with normal saline group, 46 protein spots showed changed protein expression. Twelve protein spots demonstrated increased volume and 34 protein spots demonstrated decreased volume. Among spots of decreased volume, 17 spots showed statistically significant differences. Thirty-eight identified proteins were associated with alterations in energy metabolism, muscle contractile function, transcription, translation, cell proliferation, and cellular stress response. CONCLUSION: BoNT-A gives influences on muscle contractile function and energy metabolism directly or indirectly besides neurotoxic effects. Proteomic expression provides better understanding about the effect of BoNT-A on skeletal muscle.

Relationship between Physical Examinations and Two-Dimensional Computed Tomographic Findings in Children with Intoeing Gait.

OBJECTIVE: To evaluate the validity of physical examinations by assessment of correlation between physical examinations and CT measurements in children with intoeing gait and the causes of intoeing gait by age using CT measurements. METHOD: Twenty-six children with intoeing gait participated in this study. The internal and external hip rotation, thigh-foot angle and transmalleolar angle were measured. In addition, femoral anteversion and tibial torsion of the subjects were assessed using a CT scan. The measurements of torsional angles were performed twice by two raters. The correlation coefficients between physical examinations and CT measurements were calculated using Pearson correlation. The data was analyzed statistically using SPSS v12.0. RESULTS: The correlation coefficients between physical examinations and CT measurements were not high. Before 5 years of age, intoeing gait was caused by femoral anteversion in 17.86%, tibial torsion in 32.29% and the combination of causes in 35.71% of cases. After 6 years of age, the contributions changed to 29.17%, 8.33% and 45.83%, respectively. CONCLUSION: Before 5 years of age, the common cause of an intoeing gait was tibial torsion, whereas after 6 years of age it was femoral anteversion. Regardless of age, the most common cause of intoeing gait was a combination of causes. This study shows poor correlation between physical examinations and CT. Therefore, it is limiting to use physical examination only for evaluating the cause of intoeing gait in clinical practice.

Melatonin plus exercise-based neurorehabilitative therapy for spinal cord injury.

Spinal cord injury (SCI) is damage to the spinal cord caused by the trauma or disease that results in compromised or loss of body function. Subsequent to SCI in humans, many individuals have residual motor and sensory deficits that impair functional performance and quality of life. The available treatments for SCI are rehabilitation therapy, activity-based therapies, and pharmacological treatment using antioxidants and their agonists. Among pharmacological treatments, the most efficient and commonly used antioxidant for experimental SCI treatment is melatonin, an indolamine secreted by pineal gland at night. Melatonin's receptor-independent free radical scavenging action and its broad-spectrum antioxidant activity makes it an ideal antioxidant to protect tissue from oxidative stress-induced secondary damage after SCI. Owing to the limitations of an activity-based therapy and antioxidant treatment singly on the functional recovery and oxidative stress-induced secondary damages after SCI, a melatonin plus exercise treatment may be a more effective therapy for SCI. As suggested herein, supplementation with melatonin in conjunction with exercise not only would improve the functional recovery by enhancing the beneficial effects of exercise but would reduce the secondary tissue damage simultaneously. Finally, melatonin may protect against exercise-induced fatigue and impairments. In this review, based on the documented evidence regarding the beneficial effects of melatonin, activity-based therapy and the combination of both on functional recovery, as well as reduction of secondary damage caused by oxidative stress after SCI, we suggest the melatonin combined with exercise would be a novel neurorehabilitative strategy for the faster recovery after SCI.