• Nuclear Medicine and Molecular Imaging
• /
• v.40 no.3
• /
• pp.148-154
• /
• 2006

Purpose: Although radionuclide cisternography (RNC) is an useful study to detect cerebrospinal fluid (CSF) leakage in the patient with spontaneous intracranial hypotension (SIH), it sometimes fails to demonstrate the site of CSF leakage. The aim of the study is to improve the detection of leakage site of CSF and to reduce time for the study in RNC using modified protocol (m-RNC). Materials & methods : The study consists of 8 studies of 7 patients ($38{\pm}8$ years, M:F=2:5) with SIH, who underwent m-RNC following administration of 185-222 MBq of $^{99m}Tc$-DTPA into the lumbar subarachnoid space. Sequential images were obtained the whole spine with the head including urinary bladder at 10 minute, 30 minute, 1 hour, 2 hour, 4 hour and 6 hour. Radioactivity of extradural space and urinary bladder was evaluated. Results: Leakage site of CSF was identified in all 8 cases by m-RNC. Leakage site was cervicothoracic junction (CTJ, n=3), CTJ with C1-2 (n=2), CTJ with thoracic spine, thoracolumbar spine and lumbar spine (each n=1). All cases presented leakage sites within 1 hour and multiple sites, where CTJ was included in 6 cases. Only one case presented additional site in 6 hour image. Early radioactivity within the urinary bladder was noted in 6 cases, but that was fellowing after identification of the leakage site. Conclusion: Radionuclide cisternography is sensitive to detect the leakage site of CSF and is expected to improve the detection of CSF leakage site and reduce time for the study using modified protocol.

• Journal of Yeungnam Medical Science
• /
• v.19 no.2
• /
• pp.107-115
• /
• 2002

Purpose: Ga-67 scintigraphy has been used for the evaluation of tumors, especially lymphoma. Recently, Tl-201 and Tc-99m MIBI were also used to tumor imaging. Tl-201 and Tc-99m MIBI had better physiologic characteristics than Ga-67, so we studied 32 biopsy proven lymphoma patients (male 24, female 8, mean age 46 years) with Ga-67, Tl-201 or Tc-99m MIBI and compared the scan findings. Materials and Methods: Twenty-three of 32 patients were injected 74-111 MBq (2-3 mCi) of Tl-201, before chemotherapy and imaged with dual-headed SPECT (Prism 2000, Picker, USA) at 30 minutes after injection. Delayed images were obtained after 3 hr in 8 patients. Twenty seven of 32 patients were injected 740 MBq (20 mCi) of Tc-99m MIBI and imaged at 30 minutes after injection. 111-185 MBq (3-5 mCi) of Ga-67 was injected in 12 patients and imaged at 48 and 72 hours after injection. Twenty eight patients were diagnosed as non-Hodgkin's lymphoma and others were Hodgkin's lymphoma. Results: Twenty patients were positive on Tl-201 scan and 3 patients showed negative findings. One of these 3 patients, Tc-99m MIBI and Ga-67 scan were positive. Twenty two patients were positive on Tc-99m MIBI scan and 5 patients showed negative findings. One of these 5 patients, Tl-201 was positive and 2 were positive on Ga-67 scan. Ten of 12 patients showed positive findings on Ga-67 scan. The sensitivity of these agents were 83.3%, 87.0% and 81.5% for Ga-67, Tl-201 and Tc-99m MIBI, respectively. The sensitivity was highest in Tl-201 scan, but there were no significant differences among three tests. In this study, there was no significant difference of uptake ratios between early and delayed images of Tl-201. Conclusion: Scintigraphy with Tl-201 and Tc-99m MIBI in lymphoma patients have similar sensitivity with Ga-67.

• Food Science of Animal Resources
• /
• v.30 no.1
• /
• pp.95-101
• /
• 2010

Folate loaded WPI (whey protein isolate) nanoparticles were prepared using the cold-induced gelation process. The aim of this work was to investigate the effects of process parameters, such as the concentration of the WPI solution, pH, temperature, etc, on the properties of nanoparticles. The results show that the smallest nanoparticles were obtained when a WPI concentration of 1% was used at a pH of 8.0 (<330 nm). In the case of the concentration of $CaCO_3$, the smallest particles were obtained at a concentration of 5 mM. Alginate produced the smallest mean size with the narrowest particle size distribution, while the largest particles were prepared with k-carrageenan. As the w:o ratio increased, the mean particle size also increased. When the release profile was analyzed, the particles were shown to be stable for more than 6 h at a pH of 1.2, where almost all of the folic acid was released within 2 h in the dissolution media of PBS at a pH of 7.4. Thus, the process parameters appear to be important factors that affect the properties of nanoparticles.

• Progress in Medical Physics
• /
• v.18 no.3
• /
• pp.149-160
• /
• 2007

Recent advent of 64-multidetctor (MD) CT enables more coverage of Z-axis in the perfusion imaging. The purpose of this study was to evaluate the clinical usefulness of perfusion CT by using 64-MD CT in detecting the lesion in patients with acute stroke. The perfusion CT was performed by using 64-MD CT in 62 consecutive patients who were initially suspected to have subacute ischemic stroke symptoms during the period of recent 9 months. These patients had subacute stroke (n=62). CT scanning was conducted with Jog Mode which provided 16 imaging slices with 5 mm of slice thickness, and 8 cm of coverage in Z-axis. Scan interval was 1 seconds for each imaging slice and total 15 scans were repeated. After CT scanning, perfusion maps (CBV, CBF, MTT and TTP) were created at Extended Brilliance Workstation. The CBV and CBF maps showed that lesions were smaller images. While on the MTT and TTP map lesions were seen to be larger fifty-one were large than they appeared on these images. Two slices of perfusion maps obtained at the level of the basal ganglia were chosen to simulate conventional older perfusion CT with 8 cm of coverage in Z-axis. TTP and MTT maps may be clinically useful for evaluation of the penumbral zone in cases of aubacute cerebral ischemic stroke. The perfusion CT is useful in the assessment of acute stroke as an initial imaging modality.

• The KIPS Transactions:PartC
• /
• v.14C no.4
• /
• pp.349-358
• /
• 2007

Ethernet Passive Optical Network(EPON), which is one of PON technologies for realizing FTTx(Fiber-To-The-Curb/Home/Office), can cost-effectively construct optical access networks. In addition, EPON can provide high transmission rate up to 10Gbps and it is compatible with existing customer devices equipped with Ethernet card. To effectively control frame transmission from ONUs to OLT EPON can use Multi-Point Control Protocol(MPCP) with additional control functions in addition to Media Access Control(MAC) protocol function. For EPON, many researches on intra- and inter-ONU scheduling algorithms have been performed. Among the inter-ONU scheduling algorithms, IPS(Interleaved Polling with Stop) based on polling scheme is efficient because OLT assigns available time portion to each ONU given the request information from all ONUs. Since the IPS needs an idle time period on uplink between two consecutive frame transmission periods, it wastes time without frame transmissions. In this paper, we propose a dynamic bandwidth allocation algorithm to increase the channel utilization on uplink and evaluate its performance using simulations. The simulation results show that the proposed Two-phase Cycle Danamic Bandwidth Allocation(TCDBA) algorithm improves the throughput about 15%, compared with the IPS and Fast Gate Dynamic Bandwidth Allocation(FGDBA). Also, the average transmission time of the proposed algorithm is lower than those of other schemes.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.35 no.5
• /
• pp.451-457
• /
• 2011

The main objective of this study is to investigate the variation in the ignition characteristics of coals as a function of moisture content in a laminar flow reactor (LFR) equipped with a fuel moisture micro-supplier designed by the Pusan Clean Coal Center. The volatile ignition position and time were observed experimentally when a pulverized coal with moisture was fed into the LFR under burning conditions similar to those at the exit of the pulverizer and real boiler. The reaction-zone temperature along the centerline of the reactor was measured with a $70-{\mu}m$, R-type thermocouple. For different moisture contents, the volatile ignition position was determined based on an average of 15 to 20 images captured by a CCD camera using a proprietary image-processing technique. The reaction zone decreased proportionally as a function of the moisture content. As the moisture content increased, the volatile ignition positions were 2.92, 3.36, 3.96, and 4.65 mm corresponding to ignition times of 1.46, 1.68, 2.00, and 2.33 ms, respectively. These results indicate that the ignition position and time increased exponentially. We also calculated the ignition-delay time derived from the adiabatic thermal explosion. It showed a trend that was similar to that of the experimental data.

• The KIPS Transactions:PartD
• /
• v.9D no.2
• /
• pp.235-242
• /
• 2002

We propose an advanced transaction scheduling protocol for concurrency control of multilevel secure databases in wireless mobile network environment. Wireless communication is characterized by frequent spurious disconnections. So short-lived transaction must quickly access database without any delay by long-lived one. We adapted two-phase locking protocol, namely traditional syntax-oriented serializability notions, to multilevel secure databases in wireless mobile network environment. Altruistic locking, as an advanced protocol, has attempted to reduce delay effect associated with lock release moment by use of the idea of donation. An improved form of a1truism has also been deployed for extended a1truistic locking. This is in a way that scope of data to he early released is enlarged to include even data initially not intended to be donated. Our protocol is based on extended altruistic locking, but a new method, namely bi-directional donation locking for multilevel secure databases (MLBiDL), is additionally used in order to satisfy security requirements and concurrency. We showed the Simulation experiments that MLBiDL outperforms the other locking protocols in terms of the degree of throughput and average waiting time.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.11 no.3
• /
• pp.179-196
• /
• 1986

In this paper, the peformance of a statistical packet voice/data multiplexer is studied. In ths study we assume that in the packet voice/data multiplexer two separate finite queues are used for voice and data traffics, and that voice traffic gets priority over data. For the performance analysis we divide the output link of the multiplexer into a sequence of time slots. The voice signal is modeled as an (M+1) - state Markov process, M being the packet generation period in slots. As for the data traffic, it is modeled by a simple Poisson process. In our discrete time domain analysis, the queueing behavior of voice traffic is little affected by the data traffic since voice signal has priority over data. Therefore, we first analyze the queueing behavior of voice traffic, and then using the result, we study the queueing behavior of data traffic. For the packet voice multiplexer, both inpur state and voice buffer occupancy are formulated by a two-dimensional Markov chain. For the integrated voice/data multiplexer we use a three-dimensional Markov chain that represents the input voice state and the buffer occupancies of voice and data. With these models, the numerical results for the performance have been obtained by the Gauss-Seidel iteration method. The analytical results have been verified by computer simylation. From the results we have found that there exist tradeoffs among the number of voice users, output link capacity, voic queue size and overflow probability for the voice traffic, and also exist tradeoffs among traffic load, data queue size and oveflow probability for the data traffic. Also, there exists a tradeoff between the performance of voice and data traffics for given inpur traffics and link capacity. In addition, it has been found that the average queueing delay of data traffic is longer than the maximum buffer size, when the gain of time assignment speech interpolation(TASI) is more than two and the number of voice users is small.

• Journal of Chest Surgery
• /
• v.40 no.8
• /
• pp.558-563
• /
• 2007

Background: Traumatic aortic rupture is a highly fatal condition in which a patient's outcome is strongly affected by other associated injuries. Selection of the appropriate surgical timing and the management plan is important. Material and Method: The medical records of the 15 traumatic descending thoracic aortic rupture patients who underwent the clamp & sew technique were retrospectively reviewed and checked for the presence of associated injuries and the postoperative course. Result: The hospital mortality was 6.07% (one patient). This patient died intra-operatively and the cause of the death was delayed hemoperitoneum. The mean operative time and aortic clamp time were $231{\pm}53.1$ and $13.1{\pm}5.3$ minutes, respectively. One patient complained the bowel obstructive symptoms at postoperative 10 days. We found the mechanical bowel obstruction on computed tomography of the abdomen, and segmental bowel resection was done. Conclusion: Although several surgical strategies may be appropriate for managing traumatic aortic rupture, the clamp & sew technique is a safe and effective method for the treatment of traumatic aortic injury.

• Fire Science and Engineering
• /
• v.32 no.5
• /
• pp.6-14
• /
• 2018

This study was carried out with respect to the heat release rate (HRR) properties of building wood. Heat release characteristics were measured using a cone calorimeter (ISO 5660-1) with four kinds of wood. The time to ignition measured after the combustion in $25kW/m^2$ external heat flux was 35 to 55 s. Time to ignition of both lauan and red pine was marked with the most delayed value in each of 54 s, 55 s. The maximum heat release rate ($HRR_{peak}$) was $156.87{\sim}235.1kW/m^2$, and the risk of early fire was highest in spruce. Total heat release of red pine was obtained in the highest value with $114.2MJ/m^2$. The mean effective heat of combustion of Japanese cedar was 19.1 MJ/kg and the highest among the samples. Fire risk of wood by FPI was orderly increased from lauan ($0.2468s{\cdot}m^2/kW$), red pine ($0.2339s{\cdot}m^2/kW$), spruce ($0.2308s{\cdot}m^2/kW$) to Japanese cedar ($0.2231s{\cdot}m^2/kW$). Fire risk of wood by FGI get increased from lauan ($0.5088kW/m^2{\cdot}s$), red pine ($0.5111kW/m^2{\cdot}s$), Japanese cedar ($2.8522kW/m^2{\cdot}s$) to spruce ($3.0662kW/m^2{\cdot}s$). Therefore, the risk of fire on the heat release characteristics of woods were found that spruce and Japanese cedar showed the high value compared with the other specimens.