• Journal of Sensor Science and Technology
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• v.13 no.3
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• pp.230-235
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• 2004

This paper describes the design, fabrication and characteristics of a piezoelectric valve using MCA(Multilayer ceramic actuator). The MCA valve, which has the buckling effect, consists of three separate structures; MCA, a valve actuator die and an a seat die. The design of the actuator die was done by FEM modeling and displacement measurement, respectively. The valve seat die with 6 trenches was made, and the actuator die, which is driven to MCA under optimized conditions, was also fabricated. After Si-wafer direct bonding between the seat die and the actuator die, MCA was also anodic bonded to the seat/actuator die structure. PDMS sealing pad was fabricated to minimize a leak-rate. It was also bonded to seat die and SUS package. The MCA valve shows a flow rate of 9.13 seem at a supplied voltage of 100 V with a 50% duty cycle, maximum non-linearity was 2.24% FS and leak rate was $3.03{\times}10^{-8}pa{\codt}m^{3}/cm^{2}$. Therefore, the fabricated MCA valve is suitable for a variety of flow control equipment, a medical bio-system, automobile and air transportation industry.

• Journal of Veterinary Science
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• v.24 no.6
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• pp.74.1-74.15
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• 2023

Background: Antibiotic beads are used to treat local bacterial infections by delivering high drug concentrations to infected tissue. Objectives: This study examined the elution characteristics of metronidazole from metronidazole-calcium sulfate (MCa) and metronidazole-calcium-potassium sulfate (MCaK) beads over 20 days and the antibacterial efficacy of the beads after storage. Methods: The MCa and MCaK beads were prepared by mixing 250 mg of metronidazole and 10 g of calcium sulfate hemihydrate with water and a 3% potassium sulfate solution, respectively. The beads were placed in phosphate-buffered saline for the elution study. The metronidazole eluents were determined using high-performance liquid chromatography. The microstructures were examined by scanning electron microscopy (SEM), and the antimicrobial activity was evaluated by a microbioassay. Results: For the 20-day study, the total amount of metronidazole released was greater in the MCa beads than in the MCaK beads by 6.61 ± 0.48 mg (89.11% ± 3.04%) and 4.65 ± 0.36 mg (73.11% ± 4.38%), respectively. The amounts of eluted drugs from the MCa and MCaK beads were higher than the minimum inhibitory concentration at 0.5 ㎍/mL against anaerobic bacteria at both 20 days and 14 days. SEM showed that calcium crystals on the outer surface had dissolved after elution, and thinner calcium crystals were prominent in the MCaK beads. The MCa and MCaK beads exhibited antibacterial activity after setting, followed by storage at room temperature or 4℃ for 21 days. Conclusions: The MCa beads could release more drug than the MCaK beads, but all eluted metronidazole amounts were effective in controlling bacterial infections. Both metronidazole beads could be stored at ambient temperature or in a refrigerator.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.04b
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• pp.129-132
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• 2004

This paper describes the design, fabrication and characteristics of a piezoelectric valve using MCA(Multilayer ceramic actuator). The MCA valve, which has the buckling effect, consists of three separate structures; MCA, a valve actuator die and an a seat die. The design of the actuator die was done by FEM modeling and displacement measurement, respectively. The valve seat die with 6 trenches was made, and the actuator die, which is driven to MCA under optimized conditions, was also fabricated. After Si-wafer direct bonding between the seat die and the actuator die, MCA was also anodic bonded to the seat/actuator die structure. PDMS sealing pad was fabricated to minimize a leak-rate. It was also bonded to seat die and SUS package. The MCA valve shows a flow rate of 9.13 sccm at a supplied voltage of 100 V with a 50 % duty cycle, maximum non-linearity was 2.24 % FS and leak rate was $3.03{\times}10^{-8}\;pa{\cdot}m^3/cm^2$. Therefore, the fabricated MCA valve is suitable for a variety of flow control equipment, a medical bio-system, automobile and air transportation industry.

• Journal of Korean Physical Therapy Science
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• v.5 no.4
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• pp.785-794
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• 1998

We have made a survey of 40 patients in the university hospitals and oriental medical centers in Seoul from Sep. 1, 1997 to Mar. 1, 1998. We sampled 25 of them and the result shows that there were 12 MCA damaged patients(48%), 5 SAH(20%), 5 ACA(20%), 2 PCA (8%), 1 PCOA(4%). The number of MCA patients were the most. 1. As the cause of each disease, 4 of the 12 MCA damaged patients(33.35%) have infarction and cerebral hemorrhage, 2 of 5 SAH patients(40%) have cerebral hemorrhage and head injury, 3 ACA damaged patients have cerebral hemorrhage. 11 of 25 brain bloodvessel damaged patients(44%) were hemorrhage patients. 2. Rt. hemiparesis was the main symptom of 6 of 12 MCA damaged patients(50%) and 3 of 5 SAH patients(60%), and the main symptom of 3 of 5 ACA patients(60%) was Lt. hemiparesis. The main symptom of 13 of 25 brain bloodvessel damaged patients(52%) was Lt. hemiparesis 11 of them(44%) Rt. hemiparesis, and 1 of them(8.3%) Quadriplegia. 3. Language was the most well preserved function. 12 MCA damaged patients could understand language. 4. Retraction of shoulder girdle, among VIE flexor synergy, was the most frequent element because 9 of 12 MCA damaged patients had it. Among VIE flexor synergy, 5 SAH patient's most frequent synergy was Elbow flexion because all of them had it. All of 5 ACA damaged patients have shoulder girdle elevation, shoulder joint, hyperextension, abduction, and external rotation among VIE flexor synergy. 5. 7 of 12 MCA damaged patients(58.3%) were stereognosis handicapped patients, 3 of 5 SAH patients(60%) have handicap of position sense, light touch, and temperature, 3 of 5 ACA patients(60%) have position handicap. 13 of brain bloodvessel damaged patients(52%) have light touch handicap. 6. 8 of MCA damaged patients(66.7%) have facial palsy, 4 of SAH damaged patients(80%) have memory and action decline, and 3 of ACA damaged patients(60%) have action decline and facial palsy. The problem of Hemiplegia is very extensive from muscle weakness, atrophy, or deformation to psychical problems. Therefore physical therapists should have sufficient interest in psychological handicap as well as physical handicap as they deal with adult hemiplegia.

• Journal of Korean Neurosurgical Society
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• v.51 no.5
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• pp.292-295
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• 2012

Many reports have been published on complications related to middle cerebral artery (MCA) aneurysm surgical clipping procedures. We report an emergency intracranial in situ bypass surgery case which was performed as a rescue procedure after aneurysmal neck laceration during clipping of an MCA large aneurysm. In this case, we performed in situ M3-superficial temporal artery (STA) interposition graft-M3 bypass procedure. If a STA-MCA anastomosis is not available under MCA flow obstruction, we can consider an emergency in situ MCA-MCA bypass procedure with or without an STA interposition graft.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.3
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• pp.235-245
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• 2008

Purpose: The HSV1-tk gene has been extensively studied as a type of reporter gene. In hepatocellular carcinoma (HCC), only a small proportion of patients are eligible for surgical resection and there is limitation in palliative options. Therefore, there is a need for the development of new treatment modalities and gene therapy is a leading candidate. In the present study, we investigated the usefulness of substrate, 2'-fluoro-2'-deoxy-1-${\beta}$-D-arabino-furanosyi-5-[$^{124/125}I$]iodo- uracil ([$I^{124/125}I$]FIAU) as a non-invasive imaging agent for HSV1-tk gene therapy in hepatoma model using small animal PET. Material and Methods: With the Morris hepatoma MCA cell line and MCA-tk cell line which was transduced with the HSV1-tk gene, in vitro uptake and correlation study between [$^{125}I$]FIAU uptake according to increasing numeric count of percentage of MCA-tk cell were performed. The biodistribution data and small animal PET images with [$^{124}I$]FIAU were obtained with Balb/c-nude mice bearing both MCA and MCA-tk tumors. Results:, Specific accumulation of [[$^{125}I$]FIAU was observed in MCA-tk cells but uptake was low in MCA cells. Uptake in MCA-tk cells was 15 times higher than that of MCA cells at 480 min. [$^{125}I$]FIAU uptake was linearly correlated (R2 =0.964, p =0.01) with increasing percentage of MCA-tk numeric cell count. Biodistribution results showed that [$^{125}I$]FIAU was mainly excreted via the renal system in the early phase. Ratios of MCA-tk tumor to blood acting were 10, 41, and 641 at 1 h, 4 h, and 24 h post-injection, respectively. The maximum ratio of MCA-tk to MCA tumor was 192.7 at 24 h. Ratios of MCA-tk tumor to liver were 13.8, 66.8, and 588.3 at 1 h, 4 h, and 24 h, respectively. On small animal PET, [$^{124}I$]FIAU accumulated in substantial higher levels in MCA-tk tumor and liver than MCA tumor. Conclusion: FIAU shows selective accumulation to HSV1-tk expressing hepatoma cell tumors with minimal uptake in normal liver. Therefore, radiolabelled FIAU is expected to be a useful substrate for non-invasive imaging of HSV1-tk gene therapy and therapeutic response monitoring of HCC.

• Korean Journal of Veterinary Research
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• v.26 no.1
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• pp.117-124
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• 1986

The present study was undertaken to evaluate rosette formation and NK activity of splenic lymphocytes in 3-methylcholanthrene (MCA) treated mice. Mice were sensitized iv with 0.1ml of 1% sheep red blood cell (SRBC) suspension were treated with a single ip injection of olive oil alone or with different doses of MCA in oil at various time before or after sensitization, and were challenged at 4 days after SRBC. Rosette formation and NK activity of splenic lymphocytes were measured at 24 hours after challenge. Erythrocyte(E) rosette formation of splenic lymphocytes was significantly depressed in mouse treated with large dose of MCA (5~50mg) regardless of injecting time. But, there was no difference in the response between the treated with small dose of MCA (0.5mg). Whereas erythrocyte-antibody(EA) rosette or erythrocyte-antibody-complement(EAC) rosette forming cells were significantly depressed by MCA. Under small dose of MCA (0.5mg), any difference of NK activity was not observed in all course of injecting time. But, under large dose of MCA, the activity was markedly inhibited to about half the values seen in control and this suppression was transient, resulting that the normal level was reached again 19 days after MCA. These results, which conform with the predictions of immunosuppression hypothesis, suggest that MCA inhibits immunological responses including NK activity and thereby allows the outgrowth of antigenic neoplastic cells.

• Journal of Korean Neurosurgical Society
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• v.30 no.sup2
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• pp.281-288
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• 2001

Objectives : The purpose of this study is to evaluate the usefulness of SSEP monitoring during intracranial aneurysm surgery and compare the characteristics of wave change in relation to neurologic changes between ACA aneurysms and MCA aneurysms. Methods : During recent three years(between January 1997 and November 1999), intraoperative SSEP monitoring had been done in 63 operations for intracranial aneurysms. We had monitored the median nerve SSEP during surgery for aneurysms of MCA and the posterior tibial nerve SSEP for aneurysms of ACoA or ACA. A more than 50% reduction of any cortical SEP response was considered to be a significant SEP change, compared to its baseline value before the start of surgery. Changes in the SEPs were categorized as follows : Type IA, no significant amplitude changes without temporary clipping ; Type IB, no significant amplitude changes with temporary clipping ; Type II, significant changes with temporary clipping and complete return to control amplitude ; Type III, significant changes with temporary clipping and incomplete return to control amplitude ; Type IV, significant changes with temporary clipping and more decreased amplitude changes. Results : Among the 63 intraoperative monitoring, there were 37 cases of ACA aneurysms(An), and 26 of MCA An. The temporary proximal arterial occlusion during surgery were performed in 31(83.8%)cases of ACA An, 22(84.6%) of MCA An. Seven of the 31 ACA An(22.6%) and ten of the 22 MCA An(45.5%) had significant changes. The type were as follows : 4 patients with type II and 3 with type III in the ACA An ; 3 patients with type II and 3 with type III and 4 with type IV in the MCA An. In both group type II changes had no new postoperative neurological deficit. All 6 patients with type III had new neurological deficits ; However, One case in the ACA An and two cases in the MCA An. had transient neurologic deficit and improved markedly over the next two months. All 4 type IV changes in the MCA An. had permanant neurologic deficits. Two out of 30 cases(6.7%) in the ACA An. and one out of 16 cases(6.3%) in the MCA An. without significant amplitude change had new neurologic deficit postoperatively. Conclusion : Based on this study, Intraoperative SSEP monitoring during aneurysm surgery would provide useful information for detecting cerebral ischemia. SSEP response during surgery for MCA An. is more sensitive than ACA An. Otherwise, there were no meaningful difference in rate of false negativity.

• Korean Journal of Veterinary Research
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• v.26 no.1
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• pp.109-115
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• 1986

Experiments were performed on mice to investigate the effects of a polycyclic aromatic hydrocarbon, 3-methylcholanthrene (MCA) on Arthus reaction, delayed-type hypersensitivity (DTH) and antibody production to sheep red blood cells (SRBC). Mice were sensitized iv with 0.1ml of 1% SRBC suspension were treated with a single ip injection of olive oil alone or with different doses of MCA in oil (0.5~50mg/Kg) at various time before (-) or after (+) sensitization (day 0) and were challenged at 4 days after SRBC. Arthus reaction was measured at 3 hours after challenge and other responses at 24 hours. Treatment with MCA inhibited Arthus reaction and DTH to SRBC, measured by footpad swelling reaction, and this immunosuppressing effect was dependent on the dose and time of MCA treatment in relation to SRBC sensitization. Humoral immune responses as measured by serum hemagglutinin-and hemolysin-titers to SRBC were significantly depressed when MCA was injected before or at the same time of sensitization. However, the response was slightly depressed when injected after SRBC. These results indicate that MCA suppress the function of the cells involved in immune responses.

• Preventive Nutrition and Food Science
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• v.4 no.4
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• pp.255-259
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• 1999

The anticarcinogenic effects of the methanol extracts from leek (buchu in Korean) kimchi and Korean cabbage kimchi were evaluated using cytotoxicity and transformation tests in C3H/10T1/2 cells. Various fractions of the 6-day fermented leek kimchi at 15$^{\circ}C$, hexane, methanol soluble, dichloromethane, ethyl acetate, butanol and aqueous fraction, were also studied in the same system. The inhibitory effect of the leek kimchi(6-day fermented at 15$^{\circ}C$, pH 4.29) was higher than that of the Korean cabbage kimchi(4-day fermented at 15$^{\circ}C$, pH 4.21) on the cytotoxicity induced by 3-methylcholanthrane (MCA) in the C3H/10T1/2 cell system. While the MCA-treated culture(control) formed 21.0 foci of type II plus III in C3H/10T1/2 cells, 100$\mu\textrm{g}$/ml of the methanol extract of the leek kimchi and that of the 4-day fermented Korean cabbage kimchi treated cultures reduced the formation of type II plus III foci to 7.4 and 11.3, respectively. Among the fractions of the leek kimchi, the dichloromethane fraction showed the highest inhibitory effect on MCA-induced cytotoxicity in C3H/10T1/2 cells. Fifty $\mu\textrm{g}$/ml of dichloromethane fraction from the leek kimchi suppressed the MCA-induced cytotoxicity by 77%. On the transformation test using MCA, the dichloromethane fraction considerably reduced the formation of type II plus III foci, especially thpe III foci. When 50$\mu\textrm{g}$/ml of dichloromethane fraction from the leek kimchi was treated, the numbers of type III foci mediated by MCA were decreased to 1.7 compared to 10 for the control. These results indicate that leek kimchi has stronger anticarcinogenic effects than Korean cabbage kimchi and that the dichloromethane fraction of the leek kimchi may contain the major compound(s) that suppress the carcinogenesis in the eukaryotic cells.