Wonnyon Kim

Asian dust storm particles induce a broad toxicological transcriptional program in human epidermal keratinocytes.

Exposure to airborne dust particles originated from seasonal Asian dust storms in Chinese and Mongolian deserts results in increased incidence of a range of diseases including asthma, contact dermatitis and conjunctivitis. The areas affected by Asian dust particles extend from East China to the west coast of North America. In order to study toxicological mechanisms in human skin, we evaluated the effects of dust particles collected during Asian dust storms (Asian dust particles) on gene expression in human epidermal keratinocytes (HEK). In HEK, exposure to Asian dust particles significantly increased gene expressions of cytochrome P450 1A1 (CYP1A1), CYP1A2, and CYP1B1, which is an indication of aryl hydrocarbon receptor (AHR) activation. In addition, Asian dust particles increased gene transcription of the cytokines IL-6, IL-8, and GM-CSF, which have broad pro-inflammatory and immunomodulatory properties. Asian dust particles significantly up-regulated expression of caspase 14 in HEK, suggesting that Asian dust particles directly affect keratinocyte differentiation. We also demonstrated that protein extract of pollen, a material frequently adsorbed onto Asian dust particles, potentially contributes to the increased transcription of IL-6, CYP1A1, CYP1A2, and CYP1B1. Taken together, these studies suggest that Asian dust particles can exert toxicological effects on human skin through the activation of the cellular detoxification system, the production of pro-inflammatory and immunomodulatory cytokines, and changes in the expression of proteins essential in normal epidermal differentiation.

Effect of administration of ketorolac and local anaesthetic infiltration for pain relief after laparoscopic-assisted vaginal hysterectomy

The efficacy of local anaesthetic infiltration and/or non-steroidal anti-inflammatory drugs for post-operative analgesia following laparoscopic-assisted vaginal hysterectomy (LAVH) was investigated in 83 patients, randomized into four groups in this double-blind, placebo-controlled study: group BK, local infiltration with bupivacaine and pre-incisional intramuscular (IM) ketorolac; group NN, saline local infiltration IM; group BN, local infiltration with bupivacaine and saline IM; group NK, local infiltration with saline and ketorolac IM. Post-operative pain scores were assessed at 1 h, 3 h, 6 h, 12 h and 24 h using a visual analogue scale (VAS). The major pain site, first analgesic request time and incidence of analgesic requests were also recorded. At 1 h, 3 h and 6 h after surgery, group BK patients had significantly lower VAS pain scores than group NN patients. The first analgesic request time was significantly longer in group BK than in groups NN, BN and NK. Pre-incisional treatment with ketorolac IM and local infiltration with bupivacaine reduced post-operative pain after LAVH.

A Comparison of Consumption and Recovery Profiles According to Anaesthetic Circuit Mode using a New Multifunctional Closed-Circuit Anaesthesia System during Desflurane Anaesthesia: A Clinical Study

This clinical study compared induction time, consumed anaesthetic dose, and haemodynamic and recovery profiles when using a new type of multifunctional anaesthesia machine (Zeus®) in semi-closed or closed circuit modes. Sixty female patients undergoing gynaecological surgery were randomly assigned to three groups and received desflurane anaesthesia through a semi-closed circuit (SCC) at fresh gas flow rates of 4 l/min (SCC 4 l/min) or 2 l/min (SCC 2 l/min), or through a closed circuit (CC). Anaesthesia was maintained at the minimum alveolar concentration for blocking the adrenergic response to painful stimulus (MACBAR) (4.6% end-tidal desflurane) during each operation. The time required to reach MACBAR was significantly shorter and the dose of desflurane was significantly smaller in the CC group compared with the other groups. There were no differences in haemodynamic and recovery profiles between the groups. It is concluded that the CC mode allowed a faster and more reliable induction, lower anaesthetic consumption and stable haemodynamic and recovery profiles.

Effect of Nicardipine on Haemodynamic and Bispectral Index Changes following Endotracheal Intubation

We investigated the effect of IV nicardipine on haemodynamic and bispectral index responses to the induction of general anaesthesia and intubation. Forty patients were randomly allocated to two groups of 20 to receive normal saline or nicardipine 15 μg/kg IV 30 s after induction. Ninety seconds later, tracheal intubation was performed. Systolic blood pressure, heart rate and bispectral index were measured at baseline, 1 min after induction, pre-intubation, and every minute until 5 min after endotracheal intubation. Rate–pressure product values were calculated. In the nicardipine group, systolic blood pressure decreased compared with the control group, and heart rate increased compared with the control group. Bispectral index and rate–pressure product showed no differences between the two groups. In conclusion, the administration of 15 μg/kg nicardipine IV does not affect anaesthetic depth in response to the induction of general anaesthesia and intubation.

Paleointensity determination of Late Cretaceous basalts in northwest South Korea: implications for low and stable paleofield strength in the Late Cretaceous

To clarify geomagnetic field behavior in the Late Cretaceous, paleointensity and rock-magnetic studies were carried out on basalts with K-Ar ages of 78.6 ± 2.5 and 73.1 ± 1.6 Ma in northwest South Korea. A total of 314 samples (262 from six lava flows and 52 from massive basalts) were subjected to Thellier-type IZZI paleointensity experiments. Through the application of seven paleointensity selection criteria that mainly verify the thermal alteration of magnetic minerals and the stability of remanence direction, fifteen paleointensity data were obtained from five of the lava flows. Based on rock-magnetic experiments and microscopic observations, it is revealed that the measured paleointensity is carried by single-domain (titano)magnetite. The site-mean paleointensities ranged 13.1−21.3 μT, which corresponds to a virtual axial dipole moment of 2.3−3.8 × 1022 Am2. The combination of this result with selected data from the IAGA paleointensity database establishes the existence of different dipole moments according to rock type. In particular, the geomagnetic field strength recorded in Late Cretaceous crystalline volcanic rock was relatively low and stable, with a mean dipole moment of 4.0 ± 1.9 × 1022 Am2 regardless of geomagnetic field reversals.

Paleomagnetic records and mineral-magnetic properties of deep-sea sediments in the NW pacific: Paleoenvironmental implication

The paleomagnetic records and mineral-magnetic properties of unconsolidated core sediment from the east Mariana Basin of the western Pacific have been analyzed to trace the time-dependent variations in sedimentary environments. Progressive alternating field demagnetization effectively extracts a stable remanent magnetization showing both normal and reverse polarities. Comparison of successive polarity changes, recorded in the sediment core, with reference magnetic polarity time-scale, reveals that the recovered sediment column was deposited since the late Pliocene. From the sediment age model, calculated sedimentation rate during the late Pliocene was 9.8 times higher than that during the Pleistocene. Considering the oceanic environments and geologic setting in the study area, the anomalous high sediment flux during the late Pliocene was probably caused by enhanced current flows, such as North Equatorial Current, associated with atmospheric circulation as well as by debris flows from adjacent sea mounts. In addition, the systematic variation of mineral-magnetic properties indicates periodical fluxes of coarse and magnetically stable particles, on the fine-grained dominant sedimentary environments. Such influxes, however, would not be related to syn-volcanic activities, because the summits of seamounts were totally blanketed by biogenic Pliocene-Pleistocene sediments. It is, hence, reasonable to interpret that paleomagnetic and mineral-magnetic data probably reflect drastic paleoenvironmental changes at the boundary between the Pliocene and Pleistocene, where strong current and atmospheric circulations decreased.

Regional Variability of Manganese Nodule Facies in the KR1 Area in KODOS Area, Northeastern Equatorial Pacific

Research Vessel Building Unit, KIOST Ansan, P. O. Box 29, Seoul 425-600, KoreaHigh-resolution bathymetry and physico-chemical properties of manganese nodules were explored to identify therelationship between morphological features and nodule occurrences in the KR1, one of the Korean contract nodulefields located in the NE Pacific. The high-resolution seabed mapping showed that the southwestern sector of theKR1 (KR1-1) was relatively deeper than the northeastern sector (KR1-2) which is occupied by small-scale sea-mounts. In terms of nodule occurrence, manganese nodules in the KR1-1 were comparatively larger (2-4 cm) withrough surface (t-type) and discoidal shapes (D-type), while those in the KR1-2 were generally small (<2 cm) withsmooth surface (s-type) and irregular shapes (I-type). In addition, the nodules in the KR1-1 had higher contents ofCu, Mn and Ni. Such connections of water depths to nodule appearances and metal contents are commonlyobserved in the Pacific nodule fields. On the other hand, the nodules in the KR1-2 tend to be controled by morpho-logical features. The seamounts in the KR1-2 might continuously provide rock fragments as new nuclei of manga-nese nodules. As a result, the nodules could not grow over than 2 cm and showed the shapes of a newbie (i.e.,smooth surface and irregular shapes). As a result, our observations indicate that occurrence features of manganesenodules could be subjected to water depths and seabed morphology simultaneously.

Evaluation of Correction Parameter for the Free-fall Grab Based Mn Nodule Abundance in the Southern Sector of the KODOS

Quantitative estimate of manganese nodules based on the operation of a free fall grab (FFG) needs to be corrected because of its less retrieval ability. Previously, the correction parameter of the nodule abundance collected by FFG was calculated based on the image analysis of the photos of bottom sediment in the northern sector of the nodule exploration area of Korea in the NE equatorial Pacific. However, nodules in the southern sector are commonly covered by sediment, which may prevent the use of the correction parameter estimated by photographic techniques. In this study, we attempted dual nodule sampling at the same location by different equipments (i.e. box corer (BC) and FFG) to examine the previous correction parameter of nodule abundance for FFG operation. During the exploration cruises in 2007 to 2009, Mn-nodules were collected from 40 stations both by BC and FFG in the southern sector. The correlation analysis between BC and FFG operations revealed that the BC collected nodules 1.43 times larger than FFG. Our result suggests that the correction parameter of 1.43 can be applied for collection of FFG data to estimate Mn-nodule distribution in the southern sector. The obtained parameter is similar to the previous parameter (1.42~1.45) calculated by the image analysis method, indicating an usefulness of new correction parameter suggested by this study.

Sources and distribution of allochthonous organic matter in surface sediment from the Seomjin River to the southern inner shelf of Korea

The spatial distributions of δ13C, δ15N, and n-alkanes were investigated to determine the source and transportation of allochthonous organic matter from the mouth of the Seomjin River to the southern inner shelf break of Korea. Total organic carbon (%) ranged from 0.3% to 1.6% (average = 0.80%, n = 81), and the C/N ratio varied from 2.4 to 12.4 (average = 6.76, n = 81). The δ13C values ranged from −25.86 to −20.26‰ (average = −21.47‰, n = 81), and δ15N values ranged from 4.37‰ to 8.57‰ (average = 6.72‰, n = 81). The contribution of the terrestrial fraction of organic matter to the total ranged from 4.4% to 97.7% (average = 24.4%, n = 81), suggesting higher amounts around the catchment area and lower amounts in the offshore area. The concentration of total n-alkanes (nC25 − nC35) was higher at the boundary between the outer bay and inner shelf break (BOBIS). Average chain length and the carbon preference index both indicated that major leaf wax n-alkanes accounted for the observed distribution of terrestrial organic matter, and were dominant in the inner shelf break (around BOBIS) and outer shelf break. Based on the spatial distribution of the total n-alkanes and the sum of nC27, nC29, and nC31, the terrestrial organic matter distribution was considered to be controlled by local oceanographic conditions, especially at the center of the BOBIS. In addition to enabling the distribution and source of terrestrial organic matter to be identified, the n-alkanes indicated that minor anthropogenic allochthonous organic materials were superimposed on the total organic materials in the central part of Yeosu Bay and the catchment area. The n-alkane indices revealed weathered petroleum contamination, with contamination levels being relatively low at the present time.

Rock-magnetic Properties of Chimneys from TA25 Seamount in the Tofua Arc, Southwest Pacific

To identify rock-magnetic properties of volcanogenic hydrothermal sulfide deposits, chimneys were obtained from the Tofua Arc in Southwest Pacific, using a remotely operated vehicle (ROV) and Grab with AV cameras (GTVs). Three different types of chimneys used in this study are a high-temperature chimney with venting fluid-temperature of about 200 o C (ROV01), a low-temperature chimney of about 80 o C (GTV01), and an inactive chimney (ROV02). Magnetic properties of ROV01 are dominated by pyrrhotite, except for the outermost that experienced severe oxidation. Concentration and grain-size of ROV01 pyrrhotite are relatively low and fine. For GTV01, both magnetic concentration and grain-size increase from interior to margin. Pyrrhotite, dominant in the core, becomes mixed with hematite in the rim of the chimney due to secondary oxidation. High concentration and large grain-size of magnetic minerals characterize the ROV02. Dominant magnetic phases are pyrrhotite, hematite and goethite. In particular, the outermost rim shows a presence of magnetite produced by magnetotactic bacterial activity. Such distinctive contrast in magnetic concentration, grain-size and mineralogy among three different types of chimney enables the rock-magnetic study to characterize an evolution of hydrothermal deposits.