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1.
Nature ; 535(7610): 131-5, 2016 07 07.
Article in English | MEDLINE | ID: mdl-27362224

ABSTRACT

Three-dimensional graphene architectures with periodic nanopores­reminiscent of zeolite frameworks­are of topical interest because of the possibility of combining the characteristics of graphene with a three-dimensional porous structure. Lately, the synthesis of such carbons has been approached by using zeolites as templates and small hydrocarbon molecules that can enter the narrow pore apertures. However, pyrolytic carbonization of the hydrocarbons (a necessary step in generating pure carbon) requires high temperatures and results in non-selective carbon deposition outside the pores. Here, we demonstrate that lanthanum ions embedded in zeolite pores can lower the temperature required for the carbonization of ethylene or acetylene. In this way, a graphene-like carbon structure can be selectively formed inside the zeolite template, without carbon being deposited at the external surfaces. X-ray diffraction data from zeolite single crystals after carbonization indicate that electron densities corresponding to carbon atoms are generated along the walls of the zeolite pores. After the zeolite template is removed, the carbon framework exhibits an electrical conductivity that is two orders of magnitude higher than that of amorphous mesoporous carbon. Lanthanum catalysis allows a carbon framework to form in zeolite pores with diameters of less than 1 nanometre; as such, microporous carbon nanostructures can be reproduced with various topologies corresponding to different zeolite pore sizes and shapes. We demonstrate carbon synthesis for large-pore zeolites (FAU, EMT and beta), a one-dimensional medium-pore zeolite (LTL), and even small-pore zeolites (MFI and LTA). The catalytic effect is a common feature of lanthanum, yttrium and calcium, which are all carbide-forming metal elements. We also show that the synthesis can be readily scaled up, which will be important for practical applications such as the production of lithium-ion batteries and zeolite-like catalyst supports.

2.
Med Sci Monit ; 25: 5062-5067, 2019 Jul 08.
Article in English | MEDLINE | ID: mdl-31283752

ABSTRACT

BACKGROUND Movement deficits in limbs ipsilesional to the damaged hemisphere in individuals with stroke have been established through various motor tasks. Nevertheless, there has been little evidence regarding hindrance of motor skill acquisition on the ipsilesional limb in patients with stroke. Therefore, we attempted to demonstrate whether the characteristics of ipsilesional deficits involved motor learning insufficiency in stroke survivors with unilateral brain damage. MATERIAL AND METHODS Thirty-six participants (18 patients with stroke and 18 normal individuals) were recruited. Patients with stroke performed a visuo-spatial tracking task in the upper limb ipsilesional to the injured hemisphere, and normal participants did the same task with the upper limb matched for the same side. The participants were required to track a target sine wave as accurately as possible while the wave was displayed on the computer screen for 15 seconds. An accuracy index was calculated for each of the trials. RESULTS We found that motor skill learning improved in both stroke and normal groups with repetitive practice. However, the normal group exhibited greater motor skill acquisition than in comparison the stroke group for motor skill improvement. Statistical analyses revealed significant differences in time effects and time x group interactions. CONCLUSIONS Our findings provide evidence that individuals with stroke might have difficulty in performing visuo-spatial movements and acquiring motor skills with the ipsilateral upper limb. Improvement of ipsilesional limb function increases self-care activity in daily life. Therefore, we recommend that clinicians adopt remedial strategies for ipsilesional limbs.


Subject(s)
Motor Skills/physiology , Stroke/physiopathology , Upper Extremity/physiopathology , Aged , Brain Injuries/physiopathology , China , Female , Functional Laterality , Humans , Male , Middle Aged , Movement , Recovery of Function , Stroke Rehabilitation/methods
3.
J Am Chem Soc ; 140(23): 7101-7107, 2018 06 13.
Article in English | MEDLINE | ID: mdl-29697259

ABSTRACT

Polycyclic aromatic hydrocarbons (PAHs) attract much attention for applications to organic light-emitting diodes, field-effect transistors, and photovoltaic cells. The current synthetic approaches to PAHs involve high-temperature flash pyrolysis or complicated step-by-step organic reactions, which lead to low yields of PAHs. Herein, we report a facile and scalable synthesis of PAHs, which is carried out simply by flowing acetylene gas into zeolite under mild heating, typically at 400 °C and generates the products of 0.30 g g-1 zeolite. PAHs are synthesized via acetylene polymerization inside Ca2+-ion-exchanged Linde type A (LTA) zeolite, of which the α-cage puts a limit on the product molecular size as a confined-space nanoreactor. The resultant product after the removal of the zeolite framework exhibits brilliant white fluorescence emission in N-methylpyrrolidone solution. The product is separated into four different color emitters (violet, blue, green, and orange) by column chromatography. Detailed characterizations of the products by means of various spectroscopic methods and mainly mass spectrometric analyses indicate that coronene (C24H12) is the main component of the blue emitter, while the green emitter is a mixture of planar and curved PAHs. The orange can be attributed to curved PAHs larger than ovalene, and the violet to smaller molecules than coronene. The PAH growth mechanism inside Ca2+-exchanged LTA zeolite is proposed on the basis of mass spectral analyses and density functional theory calculations.

4.
Eur Neurol ; 69(4): 236-41, 2013.
Article in English | MEDLINE | ID: mdl-23364310

ABSTRACT

OBJECTIVES: Little is known about optic radiation (OR) injury in intracerebral hemorrhage (ICH). We attempted to investigate OR injury in patients with ICH by diffusion tensor imaging (DTI). METHODS: Forty-three consecutive patients with putaminal hemorrhage and 40 normal healthy control subjects were recruited. DTI data were acquired at the beginning of rehabilitation (average 34 days after onset). DTI-Studio software was used to reconstruct the OR. Fractional anisotropies (FA) and fiber numbers of the ORs were measured. FA values and fiber numbers of affected ORs were described as abnormal when they were more than 2.5 SD lower than those of normal controls. RESULTS: Thirty (70%) of the 43 patients showed an OR abnormality in the affected hemisphere. In 13 (30%) patients, the affected OR was disrupted or nonreconstructable. On the other hand, of the 20 patients with preserved OR integrity, 14 (33%) had a low FA value and 3 (7%) a low FA and fiber number. The other 13 (30%) of the 43 patients had no abnormal OR findings. CONCLUSION: Seventy percent of patients showed any abnormality of OR in the affected hemisphere on DTI. This result suggests that patients with putaminal hemorrhage are at high risk of OR injury.


Subject(s)
Diffusion Tensor Imaging/adverse effects , Optic Nerve/pathology , Putaminal Hemorrhage/diagnosis , Radiation Injuries/pathology , Adult , Aged , Anisotropy , Female , Functional Laterality , Humans , Image Processing, Computer-Assisted , Male , Middle Aged , Radiation Injuries/etiology , Statistics, Nonparametric
5.
J Exerc Rehabil ; 19(3): 163-169, 2023 Jun.
Article in English | MEDLINE | ID: mdl-37435593

ABSTRACT

The talk test (TT) is subjective method to measure exercise intensity in costless and feasible manner, compared to sophisticated laboratory equipment. We attempted to investigate whether the TT was a valid method for evaluation of exercise intensity, by comparing with values derived from various physiologic markers during cardiopulmonary exercise testing on treadmill in healthy population. A total of 17 healthy subjects (12 males and 5 females) participated in this study. The TT was applied, which consisted of 3-stages difficulties demanding respiratory load while they performed the cardiopulmonary exercise testing on treadmill. In each of the TT stages, ergospirometric and psychophysiologic response marker were collected such as heart rate, oxygen consumption, respiratory exchange ratio, minute ventilation, carbon dioxide output, tidal volume, respiratory rate, and rating of perceived exertion of breathing. Statistical analyses revealed a significant difference of all dependent variables in each of three TT stages, comparing with the resting phase before the TT. The TT showed strong correlation coefficient with all variables except for rating of perceived exertion during the resting phase before the TT. According to increase of exercise intensity, all dependent variables showed a linear tendency with the stages of the TT. Our findings indicated that each of the TT stages was strongly correlated with ergospirometric variables as well as psychophysiologic response during cardiopulmonary exercise testing on treadmill. We suggested that the TT can be used to evaluate and prescribe exercise intensity of aerobic activity in cardiovascular and pulmonary rehabilitation settings.

6.
Adv Mater ; 35(51): e2307206, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37923398

ABSTRACT

Development of a novel high performing inorganic p-type thin film transistor could pave the way for new transparent electronic devices. This complements the widely commercialized n-type counterparts, indium-gallium-zinc-oxide (IGZO). Of the few potential candidates, copper monoiodide (CuI) stands out. It boasts visible light transparency and high intrinsic hole mobility (>40 cm2 V-1 s-1 ), and is suitable for various low-temperature processes. However, the performance of reported CuI transistors is still below expected mobility, mainly due to the uncontrolled excess charge- and defect-scattering from thermodynamically favored formation of copper and iodine vacancies. Here, a solution-processed CuI transistor with a significantly improved mobility is reported. This enhancement is achieved through a room-temperature vacancy-engineering processing strategy on high-k dielectrics, sodium-embedded alumina. A thorough set of chemical, structural, optical, and electrical analyses elucidates the processing-dependent vacancy-modulation and its corresponding transport mechanism in CuI. This encompasses defect- and phonon-scattering, as well as the delocalization of charges in crystalline domains. As a result, the optimized CuI thin film transistors exhibit exceptionally high hole mobility of 21.6 ± 4.5 cm2 V-1 s-1 . Further, the successful operation of IGZO-CuI complementary logic gates confirms the applicability of the device.

7.
Sci Adv ; 9(45): eadj8276, 2023 Nov 10.
Article in English | MEDLINE | ID: mdl-37948529

ABSTRACT

InAs semiconductor nanocrystals (NCs) exhibit intriguing electrical/optoelectronic properties suitable for next-generation electronic devices. Although there is a need for both n- and p-type semiconductors in such devices, InAs NCs typically exhibit only n-type characteristics. Here, we report InAs NCs with controlled semiconductor polarity. Both p- and n-type InAs NCs can be achieved from the same indium chloride and aminoarsine precursors but by using two different reducing agents, diethylzinc for p-type and diisobutylaluminum hydride for n-type NCs, respectively. This is the first instance of semiconductor polarity control achieved at the synthesis level for InAs NCs and the entire semiconductor nanocrystal systems. Comparable field-effective mobilities for holes (3.3 × 10-3 cm2/V·s) and electrons (3.9 × 10-3 cm2/V·s) are achieved from the respective NC films. The mobility values allow the successful fabrication of complementary logic circuits, including NOT, NOR, and NAND comprising photopatterned p- and n-channels based on InAs NCs.

8.
JAMA Netw Open ; 6(2): e2254069, 2023 02 01.
Article in English | MEDLINE | ID: mdl-36757698

ABSTRACT

Importance: Understanding the causes of infant mortality shapes public health, surveillance, and research investments. However, the association of single-locus (mendelian) genetic diseases with infant mortality is poorly understood. Objective: To determine the association of genetic diseases with infant mortality. Design, Setting, and Participants: This cohort study was conducted at a large pediatric hospital system in San Diego County (California) and included 546 infants (112 infant deaths [20.5%] and 434 infants [79.5%] with acute illness who survived; age, 0 to 1 year) who underwent diagnostic whole-genome sequencing (WGS) between January 2015 and December 2020. Data analysis was conducted between 2015 and 2022. Exposure: Infants underwent WGS either premortem or postmortem with semiautomated phenotyping and diagnostic interpretation. Main Outcomes and Measures: Proportion of infant deaths associated with single-locus genetic diseases. Results: Among 112 infant deaths (54 girls [48.2%]; 8 [7.1%] African American or Black, 1 [0.9%] American Indian or Alaska Native, 8 [7.1%] Asian, 48 [42.9%] Hispanic, 1 [0.9%] Native Hawaiian or Pacific Islander, and 34 [30.4%] White infants) in San Diego County between 2015 and 2020, single-locus genetic diseases were the most common identifiable cause of infant mortality, with 47 genetic diseases identified in 46 infants (41%). Thirty-nine (83%) of these diseases had been previously reported to be associated with childhood mortality. Twenty-eight death certificates (62%) for 45 of the 46 infants did not mention a genetic etiology. Treatments that can improve outcomes were available for 14 (30%) of the genetic diseases. In 5 of 7 infants in whom genetic diseases were identified postmortem, death might have been avoided had rapid, diagnostic WGS been performed at time of symptom onset or regional intensive care unit admission. Conclusions and Relevance: In this cohort study of 112 infant deaths, the association of genetic diseases with infant mortality was higher than previously recognized. Strategies to increase neonatal diagnosis of genetic diseases and immediately implement treatment may decrease infant mortality. Additional study is required to explore the generalizability of these findings and measure reduction in infant mortality.


Subject(s)
Infant Mortality , Whole Genome Sequencing , Child , Female , Humans , Infant , Infant, Newborn , Causality , Cohort Studies , Infant Death , Male , California/epidemiology
9.
Am J Physiol Regul Integr Comp Physiol ; 301(4): R896-904, 2011 Oct.
Article in English | MEDLINE | ID: mdl-21795634

ABSTRACT

Detrusor overactivity (DO) persists after prostatectomy in 20% to 25% of patients with benign disease. Assuming that nonvoiding contractions (NVCs) can be used as a surrogate for DO in humans, the rat model of obstruction/deobstruction may allow us to study the pathophysiology of persistent DO after deobstruction. We investigated bladder function, with a special focus on NVCs, in rats by use of a new, modified method of obstruction and deobstruction and compared these results with those obtained by use of the conventional method. Seventy female Sprague-Dawley rats underwent 1) sham operation (n = 10), 2) obstruction by a modified method (Modif-Obs; n = 12), 3) obstruction/deobstruction by the conventional method (Conv-Obs/Deobs; n = 13), or 4) obstruction/deobstruction by the modified method (Modif-Obs/Deobs; n = 35). The Modif-Obs/Deobs animals were divided into subgroups with (DO+) and without (DO-) NVCs. Two weeks after partial urethral obstruction, the animals were deobstructed, and 1 wk later cystometry was performed with recording of intravesical and intra-abdominal pressures. NVCs were shown in all groups: Modif-Obs (80%), Conv-Obs/Deobs (100%), and Modif-Obs/Deobs (40%). In the Modif-Obs/Deobs group, bladder weight and the muscle-to-collagen ratio were higher in DO+ than in DO- rats. The Modif-Obs/Deobs group showed no mortality compared with 25% mortality in the Conv-Obs/Deobs group. The modified method may be more adequate for studying persistent DO after deobstruction, because it resulted in pressure/volume- and DO-related parameters similar to those found in the clinical situation. The persistence of DO after deobstruction may partly be due to irreversible changes in the bladder caused during the period of obstruction.


Subject(s)
Urethral Obstruction/surgery , Urinary Bladder, Overactive/physiopathology , Urologic Surgical Procedures/methods , Animals , Disease Models, Animal , Female , Rats , Rats, Sprague-Dawley , Treatment Outcome , Urinary Bladder/physiopathology , Urodynamics/physiology
10.
Anesthesiology ; 114(2): 293-301, 2011 Feb.
Article in English | MEDLINE | ID: mdl-21239969

ABSTRACT

BACKGROUND: The goal of this in vitro study was to investigate the effects of lipid emulsion (LE) on local anesthetic levobupivacaine-induced responses in isolated rat aorta and to determine whether the effect of LE is related to the lipid solubility of local anesthetics. METHODS: Isolated rat aortic rings were suspended for isometric tension recording. The effects of LE were determined during levobupivacaine-, ropivacaine-, and mepivacaine-induced responses. Endothelial nitric oxide synthase and caveolin-1 phosphorylation was measured in human umbilical vein endothelial cells treated with levobupivacaine alone and with the addition of LE. RESULTS: Levobupivacaine produced vasoconstriction at lower, and vasodilation at higher, concentrations, and both were significantly reversed by treatment with LE. Levobupivacaine and ropivacaine inhibited the high potassium chloride-mediated contraction, which was restored by LE. The magnitude of LE-mediated reversal was greater with levobupivacaine treatment than with ropivacaine, whereas this reversal was not observed in mepivacaine-induced responses. In LE-pretreated rings, low-dose levobupivacaine- and ropivacaine-induced contraction was attenuated, whereas low-dose mepivacaine-induced contraction was not significantly altered. Treatment with LE also inhibited the phosphorylation of endothelial nitric oxide synthase induced by levobupivacaine in human umbilical vein endothelial cells. CONCLUSIONS: These results indicate that reversal of levobupivacaine-induced vasodilation by LE is mediated mainly through the attenuation of levobupivacaine-mediated inhibition of L-type calcium channel-dependent contraction and, in part, by inhibition of levobupivacaine-induced nitric oxide release. LE-mediated reversal of responses induced by local anesthetics may be related to their lipid solubility.


Subject(s)
Anesthetics, Local/antagonists & inhibitors , Aorta, Thoracic/drug effects , Aorta, Thoracic/metabolism , Lipids/pharmacology , Amides/metabolism , Amides/pharmacology , Anesthetics, Local/metabolism , Animals , Bupivacaine/analogs & derivatives , Bupivacaine/antagonists & inhibitors , Bupivacaine/metabolism , Caveolin 1/drug effects , Caveolin 1/metabolism , Cells, Cultured , Dose-Response Relationship, Drug , Emulsions , Humans , In Vitro Techniques , Levobupivacaine , Male , Mepivacaine/metabolism , Mepivacaine/pharmacology , Nitric Oxide Synthase/drug effects , Nitric Oxide Synthase/metabolism , Rats , Rats, Sprague-Dawley , Ropivacaine , Solubility , Umbilical Veins , Vasoconstriction/drug effects , Vasodilation/drug effects
11.
Neurourol Urodyn ; 29(7): 1338-43, 2010 Sep.
Article in English | MEDLINE | ID: mdl-20879003

ABSTRACT

AIMS: We investigated which animal model is appropriate as a control for the spontaneous hypertensive rat (SHR) in studies of detrusor overactivity (DO). METHODS: Age-matched SHRs (n = 10), Wistar-Kyoto (WKY) rats (n = 9), Wistar-ST (Wistar) rats (n = 10), and Sprague-Dawley (SD) rats (n = 10) were studied. A balloon-fitted catheter was positioned in the abdominal cavity to record intra-abdominal pressure (IAP). Cystometric pressure- and volume-related parameters and DO-related ones during the filling phase were investigated. Of the intravesical pressure (IVP) rises above 2 cmH(2)O, DO was defined as a rise in IVP without a simultaneous change in IAP and was counted during the filling phase. RESULTS: Compared with SHRs, the WKY rats did not show a significant difference in pressure or volume parameters, but Wistar rats and SD rats showed a significant increase in volume parameters, such as bladder capacity, micturition volume, and micturition interval. Typical DO was seen in SHRs and WKY rats during the filling phase, but not in Wistar and SD rats. Furthermore, the frequency and increased amplitude of the DO were similar in WKY rats and SHRs. CONCLUSION: Although WKY rats are an appropriate control for SHRs in studies of hypertension, they may be inappropriate as controls in studies of DO, because they have inherent DO of similar frequency and amplitude as found in SHRs.


Subject(s)
Consciousness , Hypertension/physiopathology , Urinary Bladder, Overactive/physiopathology , Urinary Bladder/physiopathology , Abdominal Cavity , Animals , Disease Models, Animal , Male , Pressure , Rats , Rats, Inbred SHR , Rats, Inbred WKY , Rats, Sprague-Dawley , Rats, Wistar , Reproducibility of Results , Species Specificity , Urination , Urodynamics
12.
J Back Musculoskelet Rehabil ; 33(2): 201-207, 2020.
Article in English | MEDLINE | ID: mdl-31282397

ABSTRACT

BACKGROUND: Many studies have investigated the correlation between muscle torque and joint position sense (JPS), but few studies have been performed on the correlation between torque ratio and JPS. OBJECTIVE: The aim of this study was to investigate JPS and muscle torque ratios of agonist and antagonist muscles in the ankle and knee joints of young adults. METHODS: A total of 38 right handed healthy participants, 12 males and 26 females, were recruited. All participants measured their peak torque of knee flexor/extensor and ankle dorsiflexor/plantar flexor by using a Biodex system. They also used the Biodex to assess the proprioception through active joint reposition sense test in knee and ankle joint. Peak torque of each muscle, agonist/antagonist torque ratio and JPS error were collected, and Pearson's correlation analysis was used to examine correlations between peak torque, torque ratio and JPS error. RESULTS: For knee joints, correlations were found between flexion and extension torque, extension torque and torque ratio, and torque ratio and JPS error (r= 0.825/p= 0.000, r=-0.482/p= 0.002, and r=-0.685/p= 0.000, respectively). For ankle joints, correlations were found between dorsiflexion and plantar flexion torques, plantar flexion torque and torque ratio, plantar flexion torque and JPS, and torque ratio and JPS (r= 0.654/p= 0.000, r=-0.621/p= 0.000, r=-0.563/p= 0.000, and r=-0.761/p= 0.000, respectively). CONCLUSIONS: JPS error of lower extremity joint may be more related with agonist/antagonist torque ratio rather than peak torque. Therefore, people who will have training for reducing JPS error need to consider torque ratio, too.


Subject(s)
Ankle Joint/physiology , Knee Joint/physiology , Muscle, Skeletal/physiology , Proprioception/physiology , Range of Motion, Articular/physiology , Adult , Female , Humans , Male , Torque , Young Adult
13.
Work ; 63(1): 33-38, 2019.
Article in English | MEDLINE | ID: mdl-31127742

ABSTRACT

BACKGROUND: Walking in daily life is often accompanied by an attention-demanding task, which requires a different attentional load and external environments. Therefore, various gaits require complex and systematic interactions between several nervous systems, such as sensory association, cognitive functions, and the musculoskeletal system. OBJECTIVE: Dual-task conditions during gait can affect the interaction between cognitive processing and motor behavior. This study investigated the effect of two types of cognitive dual tasks and one type of manual dual task (MDT) on kinematic and spatiotemporal parameters of gait in young healthy adults. METHODS: We recruited 30 healthy young adults in this study. All participants performed normal gait, and two types of cognitive tasks (subtraction dual task, SDT; and working memory dual task, WMDT) and MDT (carrying a cup filled with water) during gait. This study assessed kinematic data during the stance and swing phases and spatiotemporal parameters. RESULTS: MDT gait showed a significant decrement of hip-joint movement during the stance phase compared to the normal gait (p < 0.05). Stride velocity significantly decreased during SDT and WMDT gait compared with the normal gait (p < 0.05). MDT gait showed significant decrement of all spatiotemporal parameters of gait compared with normal gait (p < 0.05). CONCLUSION: We reported that MDT gait can induce decreased hip-joint motion during the stance phase and reduced all spatiotemporal parameters to maintain balance and reduce the risk of falling. Therefore, motor dual tasks while walking would be useful as an intervention strategy to rehabilitate or train people at risk for falling.


Subject(s)
Attention/physiology , Gait/physiology , Adult , Analysis of Variance , Female , Gait Analysis , Healthy Volunteers , Humans , Male , Range of Motion, Articular/physiology , Task Performance and Analysis , Walking/physiology
14.
NeuroRehabilitation ; 22(4): 279-86, 2007.
Article in English | MEDLINE | ID: mdl-17971618

ABSTRACT

Previous studies have proven that motor deficits are expressed in the ipsi-lesional limbs of the injured hemisphere in a variety of motor tasks. However, it still remained controversial for the distinct characteristics of the motor deficits according to the dysfunction of each hemisphere related to motor control. We evaluated the performance of the ipsi-lesional limb in stroke patients and age-sex matched normal controls. Kinematic components such as the temporal variation and accuracy index were analyzed. Our findings revealed that both groups with right or left hemisphere damage showed poor accuracy in terms of complex visuomotor function. Overall, patients with left hemisphere damage exhibited temporal inconstancies in simple repetitive movement. Accordingly, the non-dominant hemisphere plays a primary role in the function of complex visuospatial accuracy, whereas the dominant hemisphere is mainly involved in the motor control of bilateral upper limbs as well as the performance of complex tasks. Therefore, we assumed that such deficits may be caused by damage of the lateralized hemispheric function, depending on the property of the performed task and hemispheric asymmetry. The manifest understanding of the ipsi-lesional motor abnormalities provides clinicians with useful neurophysiologic information, and with the necessity of careful evaluation and therapeutic intervention on the ipsi-lesional upper limb, often clinically assumed as "the non-affected side".


Subject(s)
Motor Activity/physiology , Paresis/pathology , Paresis/physiopathology , Stroke/pathology , Stroke/physiopathology , Adult , Aged , Arm , Biomechanical Phenomena , Case-Control Studies , Female , Functional Laterality , Humans , Male , Middle Aged , Paresis/etiology , Stroke/complications , Task Performance and Analysis
15.
NeuroRehabilitation ; 22(2): 77-84, 2007.
Article in English | MEDLINE | ID: mdl-17656831

ABSTRACT

OBJECTIVES: We tried to examine whether visual biofeedback tracking training (VBTT) can improve both the gait performance and cortical activation pattern in chronic stroke patients. DESIGN: We enrolled 10 chronic hemiparetic patients with stroke(mean age 46.3 +/- 5.19 years). The patients were randomly assigned to the training group (5 patients) or the control group (5 patients). VBTT was to follow the PC-generated sine waves with the knee joint electrogoniometer, and the two sine waves should appear as close to overlapping as possible on the PC monitor. The training was performed for 39 minutes/day, 5 days/week, for 4 weeks. Pre-training and post-training accuracy of tracking, functional status of gait, and functional MRI (fMRI) were measured. fMRI was performed at 1.5 T in parallel with timed knee flexion-extension movements at a fixed rate. RESULTS: The accuracy of the tracking performance, walking speed, and motor scale for gait improved in the training group. Primary sensorimotor cortex (SM1) cortical activation shifted significantly from the unaffected to the affected hemisphere in the training group. CONCLUSIONS: We demonstrated that cortical activation changes occurred with gait function improvement in chronic stroke patients throughout the 4-week VBTT program. It seems that the cortical reorganization was induced by VBTT.


Subject(s)
Biofeedback, Psychology , Gait/physiology , Motor Cortex/physiopathology , Paresis/rehabilitation , Psychomotor Performance , Stroke Rehabilitation , Adult , Female , Humans , Knee Joint/physiopathology , Male , Middle Aged , Paresis/etiology , Paresis/physiopathology , Recovery of Function/physiology , Stroke/complications , Stroke/physiopathology
16.
NeuroRehabilitation ; 22(2): 105-8, 2007.
Article in English | MEDLINE | ID: mdl-17656835

ABSTRACT

OBJECTIVES: Diffusion tensor image tracography (DTT) could be useful for exploration of the state of the corticospinal tract at the subcortical white matter level. We investigated the neural pathway associated with motor recovery in the patients with corona radiata infarct (CR) using DTT. DESIGN: Three hemiparetic patients who showed severe weakness of the affected upper extremity at stroke onset, were recruited. DTT was performed twice (subacute and chronic stage) using 1.5-T system. Three-dimensional reconstructions of the fiber tracts were obtained with FA <0.2, angle >45 degrees as termination criteria. RESULTS: In all patients, the motor function of the affected upper extremity has recovered to be functional state at second DTT scanning. The motor tracts of the affected hemisphere were observed to pass along the posterior portion of the CR infarct on both the first and second DTT. CONCLUSIONS: It seems that the motor function of the affected upper extremity of the patients recovered via the posterior portion of infarct. This finding may reflect functional reorganization of the motor pathway following damage to the corticospinal tract.


Subject(s)
Brain Infarction/physiopathology , Internal Capsule , Motor Activity/physiology , Paresis/physiopathology , Pyramidal Tracts/physiopathology , Recovery of Function/physiology , Aged , Arm/physiopathology , Brain Infarction/complications , Diffusion Magnetic Resonance Imaging , Female , Humans , Male , Middle Aged , Paresis/etiology , Time Factors
17.
Sci Rep ; 7(1): 11460, 2017 09 13.
Article in English | MEDLINE | ID: mdl-28904356

ABSTRACT

We report the remarkably high electrical conductance of microporous 3D graphene-like carbons that were formed using lanthanum (La)-catalyzed synthesis in a Y zeolite (LaY) template investigated using conductive atomic force microscopy (C-AFM) and theoretical calculations. To uncover the relation between local electrical conductance and the microporous structures, we tuned the crystallographic ordering of LaY-templated carbon systems by changing the heating temperature. The structure of the LaY-templated carbon prepared at the higher temperature has graphene-like sp 2 hybridized bonds, which was confirmed using high-resolution transmission electron microscopy and X-ray diffraction measurements. C-AFM current-voltage spectroscopy revealed that the local current flow in the LaY-templated carbon depends on the quantity of C-C bonds within the narrow neck between the closed supercages (i.e. there are three types of carbon: carbon with heat treatment, carbon without heat treatment, and carbon synthesized at low temperature). The difference in electrical conductance on the LaY-templated carbon was also confirmed via theoretical computation using the Boltzmann transport theory and the deformation potential theory based on the density functional theory. These results suggest that the degree of order of the pores in the 3D zeolite-templated carbon structures is directly related to electrical conductance.

18.
Restor Neurol Neurosci ; 24(1): 25-9, 2006.
Article in English | MEDLINE | ID: mdl-16518025

ABSTRACT

PURPOSE: We hypothesized that diffusion tensor imaging (DTI) could be useful for exploring corticospinal tract (CST) regeneration if longitudinal changes of diffusion anisotropy can be detected. In this study, we explored the recovery of a CST partially damaged by intracerebral hematoma in a patient by DTI. METHODS: A 61-year-old female patient and six age-matched control subjects were evaluated. The patient presented with complete paralysis of the left extremities, which occurred at the onset of a spontaneous intracerebral hemorrhage (ICH) in the right corona radiata and internal capsule. Over the five-month period following onset, motor function of the affected extremities slowly recovered to the normal range. Two longitudinal DTIs were acquired from the patient (at 3 weeks and 5 months from onset) and one DTI from the control subjects. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were measured using a region of interest (ROI) method. RESULTS: On the 3-week DTI, FA values of ROIs in the ICH regions in the affected hemisphere were significantly lower, and ADC values of ROIs in the same areas were significantly higher than those of the control subjects (p<0.002). However, both mean FA and ADC values of the affected hemisphere in the 5-month DTI showed no significant differences versus those of the control.


Subject(s)
Cerebral Hemorrhage/pathology , Cerebral Hemorrhage/physiopathology , Diffusion Magnetic Resonance Imaging , Pyramidal Tracts/physiopathology , Recovery of Function/physiology , Aged , Brain Mapping , Case-Control Studies , Female , Functional Laterality , Humans , Middle Aged , Pyramidal Tracts/pathology , Time Factors
19.
NeuroRehabilitation ; 21(3): 239-43, 2006.
Article in English | MEDLINE | ID: mdl-17167193

ABSTRACT

OBJECTIVES: Diffusion tensor imaging (DTI) with fiber tractography (FT) could be useful for exploration of the state of the corticospinal tract (CST) at the subcortical white matter level. The purpose of this study was to demonstrate focal lesions of the CST in patients with diffuse axonal injury (DAI), using DTI with FT. DESIGN: Two patients with DAI and six normal control subjects were recruited to this study. DTI was performed using 1.5-T with a synergy-L Sensitivity Encoding (SENSE) head coil. Fractional anisotropy (FA) and apparent diffusion coefficients (ADC) were measured using a region of interest (ROI) method. FTs were obtained with FA <0.3 and an angle change >45 degrees as termination criteria. RESULTS: On the DTI with FT, the focal lesions, which could not observed using routine brain MRI, were detected in the left brainstem of patient 1 and in the right pons and the left and right medulla of patient 2. The patients showed significantly decreased FA values in the focal lesions compared to normal controls. CONCLUSIONS: DTI with FT demonstrated focal lesions at the brainstem that had not been revealed by conventional brain MRI; these focal lesions explained the weaknesses of the patients. We conclude that DTI with FT may be a useful modality for use in investigating the status of CST in patients with DAI.


Subject(s)
Diffuse Axonal Injury/pathology , Diffusion Magnetic Resonance Imaging , Pyramidal Tracts/pathology , Adult , Anisotropy , Female , Humans , Image Processing, Computer-Assisted , Male
20.
Yonsei Med J ; 47(1): 135-9, 2006 Feb 28.
Article in English | MEDLINE | ID: mdl-16502496

ABSTRACT

The purpose of this study was to demonstrate corticospinal tract compression that was due to a hematoma by using diffusion tensor tractography (DTT) and functional MRI (fMRI) in a patient with an intracerebral hemorrhage (ICH). A 23-year-old right-handed woman presented with severe paralysis of her right extremities at the onset of a spontaneous ICH. Over the first three days from onset, the motor function of the affected upper and lower extremities rapidly recovered to the extent that she was able to overcome applied resistance to the affected limbs, and her limbs regained normal function 3 weeks after onset. The tract of the right hemisphere originated from the primary sensori-motor cortex (SM1) and it passed through the known corticospinal tract pathway. However, the tract of the left hemisphere was similar to that of the right hemisphere except that it was displaced to the antero-medial side by the hematoma at the cerebral peduncle. Only the contralateral SM1 area centered on the precentral knob was activated during affected (right) or unaffected (left) hand movements, respectively. In conclusion, fMRI and DTT demonstrated a corticospinal tract compression due to hematoma in this patient. We conclude that the combined use of these two modalities appears to improve the accuracy of investigating the state of the corticospinal tract.


Subject(s)
Cerebral Hemorrhage/diagnosis , Diffusion Magnetic Resonance Imaging/methods , Hematoma/diagnosis , Magnetic Resonance Imaging , Pyramidal Tracts/pathology , Spinal Cord Compression/diagnosis , Adult , Cerebral Hemorrhage/complications , Cerebral Hemorrhage/pathology , Female , Hematoma/complications , Hematoma/pathology , Humans , Spinal Cord Compression/complications , Spinal Cord Compression/pathology
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