Effects of Effective Dendrite Size on Dynamic Tensile Properties of Ti-Based Amorphous Matrix Composites

In this study, dynamic tensile properties of dendrite-containing Ti-based amorphous matrix composites were examined, and effects of dendrite size on dynamic deformation were investigated. The composites contained 73 to 76 vol pct of dendrites whose effective sizes were varied from 63 to 103 mu m. The dynamic tensile test results indicated that the ultimate tensile strength increased up to 1.25 GPa, whereas the elongation decreased to 1 pct, although the overall strength and elongation trends followed those of the quasi-static tensile test. According to the observation of dynamic tensile deformation behavior, very few deformation bands were observed beneath the fracture surface in the composite containing large dendrites. In the composite containing small dendrites, deformation bands initiated inside small dendrites propagated into adjacent dendrites through the amorphous matrix, and were crossly intersect perpendicularly in widely deformed areas, which beneficially worked for elongation as well as strength.open1131sciescopu

Statistical Mapping Analysis of Brain Metabolism in Patients with Subcortical Aphasia after Intracerebral Hemorrhage: A Pilot Study of F-18 FDG PET Images

Purpose: This study was aimed to evaluate the brain metabolism in patients with subcortical aphasia after intracerebral hemorrhage (ICH) and the relationship between the severity of aphasia and regional brain metabolism, by using statistical mapping analysis of F-18 fluorodeoxyglucose positron emission tomography (F- 18 FDG PET) images. Materials and Methods: Sixteen right-handed Korean speaking patients with subcortical aphasia following ICH were enrolled. All patients underwent Korean version of the Western Aphasia Battery and the brain F-18 FDG PET study. Using statistical parametric mapping analysis, we compared the brain metabolisms shown on F-18 FDG PET from 16 patients with subcortical aphasia and 16 normal controls. In addition, we investigated the relationship between regional brain metabolism and the severity of aphasia using covariance model. Results: Compared to the normal controls, subcortical aphasia after ICH showed diffuse hypometabolism in the ipsilateral cerebrum (frontal, parietal, temporal, occipital, putamen, thalamus) and in the contralateral cerebellum (P corrected<0.001), and showed diffuse hypermetabolism in the contralateral cerebrum (frontal, parietal, temporal) and in the ipsilateral cerebellum (P FDR corrected<0.001). In the covariance analysis, the increase of aphasia quotient was significantly correlated with increased brain metabolism in both orbitofrontal cortices, the right hippocampal and the right parahippocampal cortices (P uncorrected<0.01). Conclusion: Our findings suggest that frontal, parietal, and temporal cortices, which are parts of neural network for cognition, may have a supportive role for language performance in patients with subcortical aphasia after ICH

Unique Appearance of Lamellar Cleavage Patterns on Fracture Surfaces of Ti-Based Amorphous Matrix Composite

In order to improve mechanical properties of Ti-based amorphous matrix composites basically composed of ductile beta-Ti dendrites and brittle amorphous matrix by overcoming their inherent brittle nature, their fracture mechanisms should be verified in relation with microstructure, stress intensity factor level, and crack growth rate. In this study, thus, detailed fractographic observations including the unique appearance of lamellar cleavage patterns, which has not been reported in previous studies on conventional metals and alloys, were conducted. According to fractographic results, lamellar cleavage patterns were formed by repeated interruptions of crack propagation on {100} cleavage planes by difference between dendrite orientation and loading direction. Ductile-to-brittle transition phenomenon (ductile dimpled fracture -> lamellar cleavage fracture -> ordinary cleavage fracture in dendrite areas, and vein pattern -> smooth pattern in amorphous matrix areas) occurred with increasing crack growth rate was also plausibly explained by the concept of time required for crack growth as well as dendrite orientation.open1122sciescopu

Correlation between ambulatory function and clinical factors in hemiplegic patients with intact single lateral corticospinal tract: A pilot study

To define the relationship between the complete destruction of 1 lateral corticospinal tract (CST), as demonstrated by diffusion tensor imaging (DTI) tractography, and ambulatory function 6 months following stroke. Twenty-six adults (17 male, 9 female) with poststroke hemiplegia who were transferred to the physical medicine and rehabilitation department. Participants underwent DTI tractography, which showed that 1 lateral CST had been clearly destroyed. Functional ambulation classification (FAC) scores at admission, discharge, and 6 months after discharge were used to evaluate the patients’ ability to walk. The National Institutes of Health Stroke Scale (NIHSS) and the Korean version of the modified Barthel index (K-MBI) at admission, discharge, and 6 months after discharge were used to evaluate the degree of functional recovery. Of the 26 patients, 18 were nonambulatory (FAC level 1–3), and 8 were able to walk without support (FAC level 4–6). The type of stroke (infarction or hemorrhage), site of the lesion, spasticity of lower extremities, cranioplasty, and the time taken from onset to MRI were not statistically significantly correlated with the ability to walk. However, statistically significant correlations were found in relation to age, K-MBI scores, and initial NIHSS scores. Despite the complete damage to the lesion site and the preservation of 1 unilateral CST, as shown by DTI, good outcomes can be predicted on the basis of younger age, low NIHSS scores, and high MBI scores at onset

Back Extensor Strengthening Exercise and Backpack Wearing Treatment for Camptocormia in Parkinson's Disease: A Retrospective Pilot Study

Objective To investigate the effect of a conservative treatment regime in Parkinson's disease patients with camptocormia. Methods Nine patients with Parkinson's disease were included in a retrospective pilot study of the value of back extensor strengthening exercise. Six inpatients received a 30-minute treatment, twice daily for 5 weeks, being treated on average for 34 days; while three outpatients visited the clinic and were educated for home exercise and backpack wearing treatment. Outpatients should be scheduled to visit the outpatient department to check physical status every 2–4 weeks for an average of 3 months. Results All patients except one showed statistically significant improvements in activities of daily living (ADL) and motor symptoms, as measured by flexion angle at standing posture, Unified Parkinson's Disease Rating Scale (UPDRS) II and III, and modified Hoehn-Yahr staging. Conclusion Conservative treatment is effective in postural correction of camptocormia in Parkinson's disease, as well as improvement in ADL and motor symptoms

Sonography of Affected and Unaffected Shoulders in Hemiplegic Patients: Analysis of the Relationship Between Sonographic Imaging Data and Clinical Variables

Objective To explore the relationship between a number of clinically relevant variables and sonographic imaging data in respect to the level of impairment experienced in the affected and unaffected shoulders of hemiplegic stroke patients. Method Fifty-one hemiplegic stroke patients (32 males, 19 females; 29 right-sided hemiplegics, 22 left-sided hemiplegics) participated in this study. A musculoskeletal radiologist conducted a sonographic exam on both the affected and unaffected shoulders of all patients and two physicians classified the severity of the injury on a six-point rating scale. Clinical variables including age, sex, duration of injury, spasticity and muscle power of the hemiplegic side, and level of functional activity of the shoulder were assessed. Results The sonographic rating scores of hemiplegic shoulders were positively correlated with age (p<0.01) and negatively correlated with level of muscle spasticity (p<0.05). The sonographic rating scores of unaffected shoulders were positively correlated with duration of injury (p<0.01). Affected shoulders received sonographic rating scores that reflected significantly more impairment than those of unaffected shoulders (p<0.001), and premorbid handedness did not affect the relationship between impairment rating and shoulder injury status. Conclusion Hemiplegic stroke influences not only affected shoulders, but also unaffected sides. Proper management of spasticity, enhancement of motor recovery, and avoidance of unaffected shoulder overuse should be considered to prevent shoulder problems following strokes which result in hemiplegia

Finite Element Simulation of Powder Compaction via Shock Consolidation Using Gas-gun System

AbstractShock consolidation is a promising method for consolidation of nanocrystalline metallic powders since it can prevent grain growth of nanopowders during the process due to very short processing time. However, internal cracks often occurs in powder compacts during the shock consolidation process. In this paper, finite element simulations showed that reflected tensile wave causes spall phenomena resulting internal crack of powder compaction during shock compaction process. To reduce spall phenomena, FEM simulation with changing compaction die's geometry was performed to find out relationship between shape and tensile wave intensity. Based on FEM results, new compaction die was designed and bulk nanocrystalline Cu are obtained using new compaction die

The Correlation Between Electrodiagnostic Results and Ultrasonographic Findings in the Severity of Carpal Tunnel Syndrome in Females

Objective: To determine which ultrasonographic measurement can be used as an indicator reflecting the severity of carpal tunnel syndrome (CTS), by comparing electrodiagnostic results with ultrasonographic measurements in females. Many previous studies have tried to reveal that the ultrasonography (US) can possibility be used for diagnosis and severity of CTS. However, the criteria are different by gender. Thus far, there have been many efforts towards providing patients with a CTS diagnosis and severity prediction using US, but studies’ results are still unclear due to lack of data on gender differences. Methods: We collected data from 54 female patients. We classified the severity of CTS according to electrodiagnostic results. Ultrasonographic measurements included proximal and distal cross-sectional areas of the median nerve and carpal tunnel. Results: The severity by electrodiagnostic results statistically correlated to the proximal cross-sectional area (CSA) of the median nerve and carpal tunnel. However, there was no relationship between the proximal and distal nerve/tunnel indexes and the severity by electrodiagnostic results. Conclusion: In female patients with CTS, the proximal CSAs of the median nerve and carpal tunnel increase. They correlate with the severity by electrodiagnostic findings. The CSA of the proximal median nerve could be particularly used as a predictor of the severity of CTS in female patients. However, the nerve/tunnel index is constant, irrespective of the severity of CTS

The Nerve/Tunnel Index: A New Diagnostic Standard for Carpal Tunnel Syndrome Using Sonography

Objectives—To define the relationship between body indices of healthy adults and cross-sectional areas of the carpal tunnel and median nerve and to obtain the nerve/tunnel index, which represents a new standard for diagnosing carpal tunnel syndrome using sonography. Methods—Body indices (height, weight, and body mass index) were analyzed in 60 healthy adults, and electromyography and sonography were also performed. The crosssectional areas of the proximal and distal median nerve and carpal tunnel were obtained by sonography. The proximal and distal nerve/tunnel indices were obtained by calculating the ratio between the proximal and distal cross-sectional areas of the median nerve to those of the carpal tunnel and multiplying the value by 100. Results—Although the proximal cross-sectional areas of the median nerve and body indices showed statistically significant relationships with weak positive correlations, the proximal and distal areas of the carpal tunnel showed relatively stronger correlations with body indices. Between sexes, there were significant differences in the proximal median nerve cross-sectional area (mean ± SD: male, 10.48 ± 3.21 mm2; female, 8.81 ± 3.21 mm2; P < .05) and proximal carpal tunnel area (male, 182.50 ± 21.15 mm2; female, 151.23 ± 21.14 mm2; P < .05). There was no difference in the proximal nerve/tunnel index (male, 5.80% ± 1.72%; female, 5.91% ± 1.63%). There was a statistically significant difference in the distal carpal tunnel cross-sectional area (male, 138.90 ± 20.95 mm2; female, 121.50 ± 18.99 mm2; P < .05) between sexes, but the distal median area (male, 9.99 ± 3.42 mm2; female, 8.46 ± 1.84 mm2) and distal nerve/tunnel index (male, 7.15% ± 2.00%; female, 7.01% ± 1.38%) showed no significant differences. The proximal index was significantly higher than the distal index (proximal, 5.85% ± 1.66%; distal, 7.08% ± 1.71%). Conclusions—The nerve/tunnel index is unaffected by body indices or sex and thus may be a useful and objective standard for diagnosing carpal tunnel syndrome