• Sleep Medicine and Psychophysiology
• /
• v.21 no.2
• /
• pp.74-79
• /
• 2014

Objectives: Shift work is a stressful situation. It is important to know the factors associated with the ability to adapt to a shift work schedule. The aim of the present study was to investigate the association between sleep, as well as personality variables, and the resilience of shift work nurses. Method: Self-report questionnaires were administered to 95 nurses who worked in one national university hospital. Connor-Davidson resilience scale, hospital anxiety and depression scale, morningness-eveningness scale, Pittsburgh sleep quality index, other sleep-related questionnaires, and Korean defense style questionnaires were used. Results: Age, shift work duration, off-day oversleep, depression, anxiety, adaptive defense style, and self-suppressive defense style were significantly associated with resilience (p < 0.05). Multiple regression analysis showed that age (${\beta}=0.34$, p < 0.05), depression (${\beta}=-0.25$, p < 0.05), adaptive defense style (${\beta}=0.45$, p < 0.001), and self-suppressive defense style (${\beta}=-0.19$, p < 0.05) significantly predicted the resilience of shift work nurses. Concerning individual defense mechanisms, resignation (${\beta}=-0.20$, p < 0.05), sublimation (${\beta}=0.19$, p < 0.05), omnipotence (${\beta}=0.19$, p < 0.05), and humor (${\beta}=0.20$, p < 0.05) significantly predicted the resiliency. Conclusion: The findings indicate that a specific defense style and other mechanisms were associated with the resilience of shift work nurses. A future prospective study with more participants could further clarify the relationship between sleep-related variables, as well as personality factors, and resilience of shift work nurses.

• Analytical Science and Technology
• /
• v.28 no.6
• /
• pp.453-459
• /
• 2015

Split-flow thin cell fractionation (SPLITT fractionation, SF) is a particle separation technique that allows continuous (and thus a preparative scale) separation into two subpopulations based on the particle size or the density. In SF, there are two basic performance parameters. One is the throughput (TP), which was defined as the amount of sample that can be processed in a unit time period. Another is the fractionation efficiency (FE), which was defined as the number % of particles that have the size predicted by theory. Full-feed depletion mode (FFD-SF) have only one inlet for the sample feed, and the channel is equipped with a flow stream splitter only at the outlet in SF mode. In conventional FFD-mode, it was difficult to extend channel due to splitter in channel. So, we use large scale splitter-less FFD-SF to increase TP from increase channel scale. In this study, a FFD-SF channel was developed for a large-scale fractionation, which has no flow stream splitters (‘splitter less’), and then was tested for optimum TP and FE by varying the sample concentration and the flow rates at the inlet and outlet of the channel. Polyurethane (PU) latex beads having two different size distribution (about 3~7 µm, and about 2~30 µm) were used for the test. The sample concentration was varied from 0.2 to 0.8% (wt/vol). The channel flow rate was varied from 70, 100, 120 and 160 mL/min. The fractionated particles were monitored by optical microscopy (OM). The sample recovery was determined by collecting the particles on a 0.1 µm membrane filter. Accumulation of relatively large micron sized particles in channel could be prevented by feeding carrier liquid. It was found that, in order to achieve effective TP, the concentration of sample should be at higher than 0.4%.

• Economic and Environmental Geology
• /
• v.37 no.1
• /
• pp.61-72
• /
• 2004

The soil samples were collected from the paddy field near the mine tailing dumps in the abandoned Duckum mine in Korea. In the laboratory, the soil solution was extracted from the soil using centrifuge, and analysed for the chemical composition. Physical and chemical soil properties were also analysed. Kaolinite is the main clay minerals in the paddy soil and the CEC value is therefore relatively low. Nearly all soil samples show enrichment in their trace elemental concentrations(Cd, Cu, Pb and Zn) compared with natural background level. Some soil samples exceed the soil remediation intervention values for Cd, Pb and Zn and target value for Cu, when compared with Dutch standard, whereas As, Ni and Cr are in normal range. Lead concentrations in some samples near the mine tailing dumps also exceed the standard for remediation act for agricultural area set by Korean soil conservation law. The trace elemental concentrations are higher in the paddy soil nearer the mine tailing dumps and lower for the samples from distance. Similar trend with distance is found for the soil solution chemistry but the decrease with distance from the mine tailing dumps are sharper than the changes in soil chemistry. Cadmium, Cu and Pb concentrations in the soil solution are very low, ranging from a tenth and hundredths to a maximum of several mg/l, whereas their concentrations in soils are highly enriched for natural background. Most of the trace elements are thought to be either removed by reduced iron sulphides or iron oxides, depending on the redox changes. Geochemical equilibrium modelling indicate the presence of solubility controlling solid phases for Cd and Pb, whereas Zn and Cu might have been controlled by adsorption/desorption processes. Although pollutants migration through solution phase are thought to be limited by adsorption onto various Fe, Mn solid phases, the pollutants exist as easily releasable fractions such as exchangeable site. In this case, the paddy soil would act as pollutant pool, which will supply to plants in situ. whenever the geochemical conditions favour.

• Journal of Biomedical Engineering Research
• /
• v.24 no.2
• /
• pp.133-140
• /
• 2003

In this study, muscle activity was measured using surface EMG (sEMG) during a voluntary maneuver (ankle dorsiflexion) in the supine position was compared pre and post gait training. Nine patients with incomplete spinal cord injury participated in a supported treadmill ambulation training (STAT), twenty minutes a day, five days a week for three months. Two tests, a gait speed test and a voluntary maneuver test, were made the same day, or at least the same week, pre and post gait training. Ten healthy subjects' data recorded using the same voluntary maneuvers were used for the reference. sEMG measured from ten lower limb muscles was used to observe the two features of amplitude and motor control distribution pattern, named response vector. The result showed that the average gait speed of patients increased significantly (p〈0.1) from 0.47$\pm$0.35 m/s to 0.68$\pm$0.52 m/s. In sEMG analysis, six out of nine patients showed a tendency to increase the right tibialis anterior activity during right ankle dorsiflexion from 109.7$\pm$148.5 $mutextrm{V}$ to 145.9$\pm$180.7 $mutextrm{V}$ but it was not significant (p〈0.055). In addition, only two patients showed increase of correlation coefficient and total muscle activity in the left fide during left dorsiflexion. Patients' muscle activity changes after gait training varied individually and generally depended on their muscle control abilities of the pre-STAT status. Response vector being introduced for quantitative analysis showed good Possibility to anticipate. evaluate, and/or guide patients with SCI, before and after gait training.

• The Korean Journal of Nuclear Medicine
• /
• v.39 no.6
• /
• pp.445-455
• /
• 2005

Purpose: We developed an animal SPECT system using clinical Philips ARGUS scintillation camera and pinhole collimator with specially manufactured small apertures. In this study, we evaluated the physical characteristics of this system and biological feasibility for animal experiments. Materials and Methods: Rotating station for small animals using a step motor and operating software were developed. Pinhole inserts with small apertures (diameter of 0.5, 1.0, and 2.0 mm) were manufactured and physical parameters including planar spatial resolution and sensitivity and reconstructed resolution were measured for some apertures. In order to measure the size of the usable field of view according to the distance from the focal point, manufactured multiple line sources separated with the same distance were scanned and numbers of lines within the field of view were counted. Using a Tc-99m line source with 0.5 mm diameter and 12 mm length placed in the exact center of field of view, planar spatial resolution according to the distance was measured. Calibration factor to obtain FWHM values in 'mm' unit was calculated from the planar image of two separated line sources. Te-99m point source with i mm diameter was used for the measurement of system sensitivity. In addition, SPECT data of micro phantom with cold and hot line inserts and rat brain after intravenous injection of [I-123]FP-CIT were acquired and reconstructed using filtered back protection reconstruction algorithm for pinhole collimator. Results: Size of usable field of view was proportional to the distance from the focal point and their relationship could be fitted into a linear equation (y=1.4x+0.5, x: distance). System sensitivity and planar spatial resolution at 3 cm measured using 1.0 mm aperture was 71 cps/MBq and 1.24 mm, respectively. In the SPECT image of rat brain with [I-123]FP-CIT acquired using 1.0 mm aperture, the distribution of dopamine transporter in the striatum was well identified in each hemisphere. Conclusion: We verified that this new animal SPECT system with the Phlilps ARGUS scanner and small apertures had sufficient performance for small animal imaging.

• Economic and Environmental Geology
• /
• v.45 no.2
• /
• pp.71-78
• /
• 2012

Illite-smectite mixed layers (I-S) occurring authigenically in diagenetic and hydrothermal environments reacts toward more illite-rich phases as temperature and potassium ion concentration increase. For that reason, I-S is often used as geothermometry and/or geochronometry at the field of hydrocarbons or ore minerals exploration. Generally, I-S shows X-ray powder diffraction (XRD) patterns of ultra-thin lamellar structures, which consist of restricted numbers of sillicate layers (normally, 5 ~ 15 layers) stacked in parallel to a-b planes. This ultra-thinness is known to decrease I-S expandability (%S) rather than theoretically expected one (short-stacking effect). We attempt here to quantify the short stacking effect of I-S using the difference of two types of expandability: one type is a maximum expandability ($%S_{Max}$) of infinite stacks of fundamental particles (physically inseparable smallest units), and the other type is an expandability of finite particle stacks normally measured using X-ray powder diffraction (XRD) ($%S_{XRD}$). Eleven I-S samples from the Geumseongsan volcanic complex, Uiseong, Gyeongbuk, have been analyzed for measuring $%S_{XRD}$ and average coherent scattering thickness (CST) after size separation under 1 ${\mu}m$. Average fundamental particle thickness ($N_f$) and $%S_{Max}$ have been determined from $%S_{XRD}$ and CST using inter-parameter relationships of I-S layer structures. The discrepancy between $%S_{Max}$ and $%S_{XRD}$ (${\Delta}%S$) suggests that the maximum short-stacking effect happens approximately at 20 $%S_{XRD}$, of which point represents I-S layer structures consisting of ca. average 3-layered fundamental particles ($N_f{\approx}3$). As a result of inferring the $%S_{XRD}$ range of each Reichweite using the $%S_{XRD}$ vs. $N_f$ diagram of Kang et al. (2002), we can confirms that the fundamental particle thickness is a determinant factor for I-S Reichweite, and also that the short-stacking effect shifts the $%S_{XRD}$ range of each Reichweite toward smaller $%S_{XRD}$ values than those that can be theoretically prospected using junction probability.

• Childhood Kidney Diseases
• /
• v.3 no.2
• /
• pp.209-216
• /
• 1999

Purpose : Nephrogenic diabetes insipidus (NDI) is a rare X-linked disorder associated with renal tubule resistance to arginine vasopressin (AVP). The hypothesis that the defect underlying NDI might be a dysfunctional renal AVPR2 has recently been proven by the identification of mutations in the AVPR2 gene in NDT patients. To investigate the association of mutations in th AVPR2 gene with NDI, we analyzed the AVPR2 gene located on the X chromosome. Methods : We have analyzed the AVPR2 gene in a kindred with X-linked NDI. The proband and proband's mother were analyzed by polymerase chain reaction-single strand conformational polymorphism(PCR-SSCP) and DNA sequencing of the AVPR2 gene. We also have used restriction enzyme analysis of genomic PCR product to evaluate the AVPR2 gene. Results : C to T transition at codon 202, predictive of an exchange of tryptophan 202 by cysteine(R202C) in the third extracellular domain was identified. This mutation causes a loss of Hae III site within the gene. Conclusion : We found a R202C missense mutation in the AVPR2 gene causing X-linked NDI, and now direct mutational analysis is available for carrier screening and early diagnosis.

• Korean Journal of Microbiology
• /
• v.41 no.3
• /
• pp.216-224
• /
• 2005

Chromatography has now been used successfully to provide the requisite purity for human plasma-derived biop-harmaceuticals such as coagulation factors and immunoglobulins. Recently, increasing attention has been focused on establishing efficient cleaning procedures to prevent potential contamination by microorganisms as well as carry-over contamination from batch to batch. The purpose of present study was to develop a cleaning validation system for the assurance of virus removal and/or inactivation during chromatography process. In order to establish an assay system for the validation of virus clearance during chromatography cleaning process, a quantitative real-time PCR method for porcine parvovirus(PPV) was developed, since PPV, a model virus for human parvovirus B19, has a high resistance to a range of physico-chemical treatment. Specific primers for amplification of PPV DNA was selected, and PPV DNA was quantified by use of SYBR Green I. The sensitivity of the assay was calculated to be 1.5 $TCID_{50}/ml$. The established real-time PCR assay was successfully applied to the validation of PPV removal and cleaning during SP-Sepharose cation chromatography for thrombin purification and Q-Sepharose anion chromatography for factor VIII purification. The comparative results obtained by real-time PCR assay and infectivity titrations suggested that the real-time PCR assay could be a useful method for chromatography cleaning validation and that it could have an additive effect on the interpretation and evaluation of virus clearance during the virus removal process.

• Journal of Chest Surgery
• /
• v.31 no.11
• /
• pp.1070-1075
• /
• 1998

Background: With the advent of thoracoscopy, there has been increasing interest in less invasive surgical bullectomy and pleurodesis. The recurrence rate, however, has been reported higher in surgery with thoracoscopy than with open thoracotomy and it is thought to be caused by inappropriate mechanical pleurodesis during thoracoscopic surgery. Materials and methods: We compared the short-term recurrence rates according to the intensities of pleural abrasion in 62 patients who underwent VATS for treatment of spontaneous pneumothorax from April 1996 to August 1997. The patients were divided into 2 groups: group A(n=32) included patients who received relatively weak pleural abrasion using Endo-forcep instrument for grasping the gauze, and group B(n=30) received strong pleural abrasion using conventional instrument wrapped tightly with gauze. Each intensity of pleural abrasion allowed petechia on the parietal pleura in group A, and some tearing and bleeding in group B. Results: Indications for operation, sex distribution, and age were comparable in both groups. There were no differences in chest tube indwelling time(3.78±3.35 vs 3.80±2.49 days), hospital stay(4.72±1.87 vs 4.67±2.20 days), and the amount and duration of analgesics required postoperatively. Persistent air-leak more than 7 days after surgery occurred in 4/32(12.5%) and 2/30(6.7%) in group A and B, respectively. No bleeding-related complication occured. Pneumothorax recurred 12.5%(4/32) and 0%(0/30) of patients at a mean follow-up of 9.7 and 9.6 months in group A and B, respectively, and it was statistically significant(p<0.05). Conclusions: Proper intensity of pleural abrasion is very important factor to reduce recurrence after VATS for spontaneous pneumothorax. During short-term follow-upafter surgery, we could achieve excellent result in reducing recurrence rate with VATS and strong pleural abrasion which is comparable to thoracotomy.

• Journal of the Korean earth science society
• /
• v.21 no.3
• /
• pp.287-301
• /
• 2000

In order to investigate the factors and processes affecting the vertical distributions of ozone, we analyzed the ozone profile data measured using ozonesonde from 1995 to 1997 at Pohang city, Korea. In the course of our study, we analyzed temporal and spatial distribution characteristics of ozone at four different heights: surface (100m), troposphere (10km), lower stratosphere (20km), and middle stratosphere (30km). Despite its proximity to a local, but major, industrial complex known as Pohang Iron and Steel Co. (POSCO), the concentrations of surface ozone in the study area were comparable to those typically observed from rural and/or unpolluted area. In addition, the findings of relative enhancement of ozone at this height, especially between spring and summer may be accounted for by the prevalence of photochemical reactions during that period of year. The temporal distribution patterns for both 10 and 20km heights were quite compatible despite large differences in their altitudes with such consistency as spring maxima and summer minima. Explanations for these phenomena may be sought by the mixed effects of various processes including: ozone transport across two heights, photochemical reaction, the formation of inversion layer, and so on. However, the temporal distribution pattern for the middle stratosphere (30km) was rather comparable to that of the surface. We also evaluated total ozone concentration of the study area using Brewer spectrophotometer. The total ozone concentration data were compared with those derived by combining the data representing stratospheric layers via Umkehr method. The results of correlation analysis showed that total ozone is negatively correlated with cloud cover but not with such parameter as UV-B. Based on our study, we conclude that areal characteristics of Pohang which represents a typical coastal area may be quite important in explaining the distribution patterns of ozone not only from surface but also from upper atmosphere.