• Journal of Korean Neurosurgical Society
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• v.59 no.4
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• pp.346-351
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• 2016

Objective : Early progressive infarction (EPI) is frequently observed and related to poor functional outcome in patients with middle cerebral artery (MCA) infarction caused by MCA occlusion. We evaluated the perfusion parameters of magnetic resonance imaging (MRI) as a predictor of EPI. Methods : We retrospectively analyzed patients with acute MCA territory infarction caused by MCA occlusion. EPI was defined as a National Institutes of Health Stroke Scale increment ${\geq}2$ points during 24 hours despite receiving standard treatment. Regional parameter ratios, such as cerebral blood flow and volume (rCBV) ratio (ipsilateral value/contralateral value) on perfusion MRI were analyzed to investigate the association with EPI. Results : Sixty-four patients were enrolled in total. EPI was present in 18 (28%) subjects and all EPI occurred within 3 days after hospitalization. Diabetes mellitus, rCBV ratio and regional time to peak (rTTP) ratio showed statically significant differences in both groups. Multi-variate analysis indicated that history of diabetes mellitus [odds ratio (OR), 6.13; 95% confidence interval (CI), 1.55-24.24] and a low rCBV ratio (rCBV, <0.85; OR, 6.57; 95% CI, 1.4-30.27) was significantly correlated with EPI. Conclusion : The incidence of EPI is considerable in patients with acute MCA territory infarction caused by MCA occlusion. We suggest that rCBV ratio is a useful neuro-imaging parameter to predict EPI.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.3
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• pp.22-30
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• 2006

In this paper, a systematic design method on an IPMC(ionic polymer-metal composite)-driven ZNMF(zero-net-mass-flux) pump is introduced for the flow control of an MAV's (micro air vehicle) wing. Since the IPMC is able to generate a large deformation under a low input voltage along with its ability to operate in air, and is easier to be manufactured in a small size, it is considered to be an ideal material of the actuating diaphragm. Through the numerical methods, an optimal shape of the IPMC　diaphragm was found for maximizing the stroke volume. Based on the optimal IPMC diaphragm, a proto-type ZNMF pump with a slot, was designed. By using the flight speed of the MAV considered in this work, the driving frequencies(~ 40 Hz) of IPMC diaphragm, and the flow velocity through the pump's slot, the calculated non-dimensional frequency and the momentum coefficient ensure the feasibility of the designed ZNMF pump as a flow control device.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.12
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• pp.971-974
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• 2014

A ventricular assist device (VAD) is used for bridge to heart transplantation and heart diseases. Knowing the status of a pneumatic pulsatile VAD when implanting it into the body is important: when the velocity of blood flow through the VAD is slow, a thrombus may occur, and thrombosis can be fatal to a patient. In order to determine the state of a VAD, various sensors need to be implanted. Because this introduces the risk of infection and difficulties with sensor management, we developed a method for estimating the state of a VAD indirectly via the pressure in an air tube that can be measured in vitro. We compared the measured values to in vitro experimental results. The estimated and measured values showed some errors, but the accuracy can be improved by refining the estimation process to minimize the risk of infection.

• PNF and Movement
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• v.20 no.2
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• pp.275-283
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• 2022

Purpose: This study focused on reviewing articles published in Proprioceptive Neuromuscular Facilitation (PNF) and Movement to identify the current research trends featured in the journal. Methods: First, the most frequently used keywords in the 193 studies published in 2018 volume 16, issue 1, to 2021 volume 19, issue 3, were identified to determine the popularity of different topics. Information on the following parameters was collected for each study: research type, level of the study, research topic, diagnosis, application of PNF, and techniques applied. Results: Over the four-year period reviewed, "stroke" was the most frequently used keyword, followed by "balance" and "PNF." In terms of research type, observational analytical studies were the most frequently reported (52.85%), and experimental studies were the second-most common (37.82%). Regarding the research level, it was found that level 5 studies were the most frequent, at 49.74%, and level 2 studies accounted for 28.5% of the publications. Most of the studies stated "stroke patient" (26.42%) as the study diagnosis, except for the studies that recruited healthy people (36.79%). The majority of studies did not implement PNF treatments (15.54%), but a combination of isotonic techniques was most commonly used when PNF was applied. Conclusion: A broad range of topics and types of studies have recently been featured in the journal, including neurological impairments and musculoskeletal disorders. The findings of this review provide insight into future research trends and the direction of the journal PNF and Movement.

• Biomedical Science Letters
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• v.29 no.4
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• pp.263-273
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• 2023

This study aimed to investigate effect of scalp acupuncture (SA) and repetitive transcranial magnetic stimulation (rTMS) intervention on neuromotor function in photothrombotic cerebral infarction (PCI) rat model. Sixty male SD rats were used. PCI was induced on M1 cortex of right frontal lobe. SA was performed at the Qianding (GV21), Xuanli (GB6) acupoints of ipsilesional M1. Low-frequency rTMS was delivered to contralesional M1. All rats were randomly divided into 4 groups: group A, normal (n, 15); group B, PCI without any stimulation intervention (n, 15); group C, PCI with SA (n, 15); group D, PCI with rTMS (n, 15). Rota-rod test and Ladder rung walking test (LWT) were done weekly for 8 weeks after PCI. SA or rTMS was started from post-PCI 4^th day as protocol for 8 weeks. H/E stain and IHC were done. Western blot and qRT-PCR study were performed for MAP2 and BDNF from ipsilesional M1 peri-infarction tissue. Brain MRI study was conducted to quantify the volume of cerebral infarction. As a result, left forelimb and hindlimb function significantly improved more in group C and D than control group, with expressed more BDNF and MAP2. And brain MRI showed focal infarction of right M1 after PCI, and infarction volume progressively decreased in group C and D than group B from post-PCI 5^th to 8^th week. SA or rTMS was more effective than no intervention group on neuromotor function of PCI rat model. The functional recovery was associated with stimulation intervention-related neurogenesis.

• The Korea Journal of Herbology
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• v.24 no.1
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• pp.179-189
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• 2009

Objectives : Coptidis Rhizoma (Coptis japonica MAKINO; CR) is a well known crude drug as antimicrobial, antibacterial, anti-inflammatory, antioxidant activity. However, there is no study of the effect of CR on brain infarction and it's mechanism. The aim of this study was to investigate the effects on ischemic stroke induced by photothrombotic infarction by evaluating the functional & neuronal recovery after brain infarction. Materials & Methods : Male Sprague-Dawley rats (250-300 g) were induced photothrombotic brain infarction on sensorimotor cortex, and brain infarction volume by image J software (NIH, USA) after Nissl stain, also single pellet reaching task as a functional motor recovery were observed. After orally pretreated by CR (500 mg/kg) or normal saline as a sham control before 7 days from the time of photothrombotic infarction, rats were sacrificed. After then we analysed anti-inflammatory cytokines (TNF-$\alpha$, IL-6, IL-1$\beta$), by RT-PCR and ELISA method, and immunohistochemistry (GFAP, connexin-43) as a marker of neural plasticity. Results : CR (100, 250, 500 mg/kg) decreased the infarction volume dose-dependently, however the effect of 500mg/kg of CR (CR 500) showed the best (P=0.051). Also, CR 500 decreased the infarction volume time-dependently, the most effective time was 3-7 days after stroke. Photothrombosis increased inflammatory cytokines after infarction, CR 500 suppressed significantly mRNA expression of IL-1$\beta$, IL-6 and TNF-$\alpha$. In serum, CR 500 decreased the amount of IL-1$\beta$, 12h, 24h and 48h respectively (p < 0.05), also decreased that of IL-6 and TNF-$\alpha$, 12h respectively (p < 0.05) after infarction. The more astrocytes were observed and neural plasticity was facilitated in the rat brain of CR 500 than that of sham control in immunohistochemistry. Conclusions : This results suggest that CR decrease infarction volume and improve functional motor recovery in acute stage in photothrombotic ischemic infarction model in the mechanism of anti-inflammation and promoting neural plasticity.

• Korean Journal of Radiology
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• v.20 no.6
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• pp.956-966
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• 2019

Objective: To characterize the changes in right ventricular (RV) volume, volume load, and function measured with cardiac computed tomography (CT) over the entire time course of tetralogy of Fallot (TOF). Materials and Methods: In 374 patients with TOF, the ventricular volume, ventricular function, and RV volume load were measured with cardiac CT preoperatively (stage 1), after palliative operation (stage 2), after total surgical repair (stage 3), or after pulmonary valve replacement (PVR) (stage 4). The CT-measured variables were compared among the four stages. After total surgical repair, the postoperative duration (POD) and the CT-measured variables were correlated with each other. In addition, the demographic and CT-measured variables in the early postoperative groups were compared with those in the late postoperative and the preoperative group. Results: Significantly different CT-based measures were found between stages 1 and 3 (indexed RV end-diastolic volume [EDV], 63.6 ± 15.2 mL/m² vs. 147.0 ± 38.5 mL/m² and indexed stroke volume (SV) difference, 7.7 ± 10.3 mL/m² vs. 32.2 ± 16.4 mL/m²; p < 0.001), and between stages 2 and 3 (indexed RV EDV, 72.4 ± 19.7 mL/m² vs. 147.0 ± 38.5 mL/m² and indexed SV difference, 5.7 ± 13.1 mL/m² vs. 32.2 ± 16.4 mL/m²; p < 0.001). After PVR, the effect of RV volume load (i.e., indexed SV difference) was reduced from 32.2 mL/m² to 1.7 mL/m². Positive (0.2 to 0.8) or negative (-0.2 to -0.4) correlations were found among the CT-based measures except between the RV ejection fraction (EF) and the RV volume load parameters. With increasing POD, an early rapid increase was followed by a slow increase and a plateau in the indexed ventricular volumes and the RV volume load parameters. Compared with the preoperative data, larger ventricular volumes and lower EFs were observed in the early postoperative period. Conclusion: Cardiac CT can be used to characterize RV volume, volume load, and function over the entire time course of TOF.

• The Journal of the Korean life insurance medical association
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• v.28 no.1_2
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• pp.11-14
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• 2009

It is common to find cerebral infarct and hemorrhage without definite neurologic signs but with lesions on neuroimaging. These lesions are called silent lacunar infarct and cerebral microbleed. Silent lacunar infarct are frequently seen in the elderly and are associated with clinically apparent stroke and vascular dementia. Known stroke risk factors, such as hypertension, diabetes mellitus, smoking, hypercholesterolemia and heart problems may increase the risk of silent lacunar infarct. Metabolic syndrome, homocysteinemia, renal failure and intima media thickness(IMT) are also other risk factors of the silent lacunar infarct. Cerebral microbleed, lacunar infarct and intracerebral hemorrhage(ICH) have similar pathology and pathogenesis. So, cerebral microbleed are coexisted with lacunar infarct, leukoaraiosis, hypertensive ICH and vascular dementia. Cerebral microbleed are associated with volume and recurrence of ICH. Also cerebral microbleed may reflect baseline status of blood brain barrior disruption. Silent lacunar infarct and cerebral microbleed are very important to clinical management, but in the aspect of insurance medicine and independent medical examiners, these lesions are not subject of evaluation for handicap.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.8
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• pp.1141-1148
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• 2008

One of the methods to increase the efficiency of an engine is to expand pressures obtained from combustions equal to the pressure of atmosphere as much as possible and then convert thermal energy into mechanical energy also as much as possible. In this research, the Diesel cycle was thermodynamically interpreted to evaluate the possibility of high efficiency by converting Diesel engines to the Atkinson cycle, and general cycle features were analyzed after comparing these two cycles. In the case of fuel air the Diesel-Atkinson cycle considering intake and exhaust similar to real cycles, the value of thermal efficiency and average effective pressure increased, though their values were smaller than those of standard air amount cycle, when expansion compression ratio increased. When normal Diesel engines of which compression stroke and expansion stroke are all the same, was converted to the Atkinson cycle by changing the time of intake value close, combustion pressure reduced due to reduced expansion compression ratio and intake air amount due to decreased effective cycle volume.

• Journal of Chest Surgery
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• v.21 no.6
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• pp.979-983
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• 1988

Calcium channel blockers may prevent myocardial injury during cardioplegia and reperfusion. This study was done to evaluate the effects of diltiazem cardioplegia on myocardial protection during ischemic arrest and recovery of myocardial function after reperfusion. Four formulations of crystalloid cardioplegic solutions, GIK solution[group I, n=12], diltiazem[lug/ml GIK] in GIK solution[group II, n=7], ],diltiazem[2ug/ml GIK] in GIK solution[group III, n=6] and diltiazem[4ug/ml GIK] in GIK solution[group IV, n=6] were compared in isolated working rat heart subjected to a long period [2 hours] of hypothermic arrest with multi-dose infusion. Diltiazem cardioplegia[group II, III and IV]was found to be superior in nearly all aspects. Diltiazem cardioplegia showed faster recovery of regular rhythm and lower incidence of ventricular fibrillation than group I did. In comparing mechanical function in all experimental hearts, the mean postischemic recoveries of aortic flow, cardiac output, peak aortic pressure, stroke volume and stroke work[expressed as a percentage of its preischemic control] were significantly greater in group II, III and IV[diltiazem cardioplegia] than in group I. The infused amount of cardioplegic solution was more increased by the addition of diltiazem to GI K solution. [p < 0.01] Creatine kinase leakage tended to be lower in hearts receiving diltiazem cardioplegia, especially in group III and IV[p<0.05] than in those receiving GIK solution only[group I]. Diltiazem cardioplegia results in the increased flow of cardioplegic solution and the decreased ischemic injury of myocardium during ischemic arrest and the improved recovery of myocardial function after reperfusion, and a dose-response relation must be established before clinical use.