• Journal of Ecology and Environment
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• v.46 no.1
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• pp.31-40
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• 2022

Background: Plant vegetation appears in heterogeneous and patchy forms in arid and semi-arid regions. In these regions, underneath the plant patches and the empty spaces between them are covered by biological soil crusts (moss, lichen, cyanobacteria, and fungi). Biological soil crusts lead to the formation and development of fertile islands in between vegetation patches via nitrogen and carbon fixation and the permeation of runoff water and nutrients in the soil. Results: The present study has investigated the association of biological soil crusts, the development of fertile islands, and the formation of plant patches in part of the Takht-e Soltan protected area, located in Khorasan Razavi Province, Iran. Three sites were randomly selected as the working units and differentiated based on their geomorphological characteristics to the alluvial fan, hillslope, and fluvial terrace landforms. Two-step systematic random sampling was conducted along a 100-meter transect using a 5 m² plot at a 0-5 cm depth in three repetitions. Fifteen samplings were carried out at each site with a total of 45 samples taken. The results showed that the difference in altitude has a significant relationship with species diversity and decreases with decreasing altitude. Results have revealed that the moisture content of the site, with biocrust has had a considerable increase compared to the other sites, helping to form vegetation patterns and fertile islands. Conclusions: The findings indicated that biological crusts had impacted the allocation of soil parameters. They affect the formation of plant patches by increasing the soil's organic carbon, nitrogen, moisture and nutrient content provide a suitable space for plant growth by increasing the soil fertility in the inter-patch space.

• International Journal of Oral Biology
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• v.34 no.4
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• pp.215-222
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• 2009

Medial vestibular nucleus (MVN) neurons are involved in the reflex control of the head and eyes, and in the recovery of vestibular function after the formation of peripheral vestibular lesions. In our present study, whole cell patch clamp recordings were carried out on MVN neurons in brainstem slices from neonatal rats to investigate the actions of a group I metabotropic glutamate receptor (mGluR) agonist upon synaptic transmission and ionic currents. Application of the mGluR I agonist (S)-3,5- dihydroxyphenylglycine (DHPG) increased the frequency of miniature inhibitory postsynaptic currents (mIPSCs) but had no effect upon amplitude distributions. To then identify which of mGluR subtypes is responsible for the actions of DHPG in the MVN, we employed two novel subtype selective antagonists. (S)-(+)-$\alpha$-amino-a-methylbenzeneacetic acid (LY367385) is a potent competitive antagonist that is selective for mGluR1, whereas 2-methyl-6-(phenylethynyl)-pyridine (MPEP) is a potent noncompetitive antagonist of mGluR5. Both LY367385 and MPEP antagonized the DHPG-induced increase of mIPSCs, with the former being more potent. DHPG was also found to induce an inward current, which can be enhanced under depolarized conditions. This DHPG-induced current was reduced by both LY367385 and MPEP. The DHPG-induced inward current was also suppressed by the PLC blocker U-73122, the $IP_3$ receptor antagonist 2-APB, and following the depletion of the intracellular $Ca^{2+}$ pool by thapsigargin. These data suggest that the DHPG-induced inward current may be mainly regulated by the intracellular $Ca^{2+}$ store via the PLC-$IP_3$ pathway. In conclusion, mGluR I, via pre- and postsynaptic actions, may modulate the excitability of the MVN neurons.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.8 no.1
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• pp.1-12
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• 1996

In lots of application to heat exchanger systems, closed two-phase thermosyphons are tilted from a horizontal. If the tilt angle, especially, is less than 30$^{\circ}$, the operational performances of thermosyphon are highly dependent on tilt angle. The present study was conducted to better understand such operational behaviors as mech-anni는 of phase change, and flow patterns inside a tilted thermosyphon. For experiment, an ethanol thermosyphon with a 35% of fill charge rate was designed and manufactured, using a copper tube with a diameter 19mm and a length 1500mm. Through a series of test, the tilt angle was kept constant at each of 4 different values in the range 10~25deg. and the heat supply to the evaporator was stepwisely increased up to 30㎾/$m^2$. When a steady state was established to the thermosyphon for each step of thermal loads, the wall temperature distribution and vapor temperature at the condenser were measured. The wall temperature distributions demonstrated a formation of dry patch in the top end zone of the evaporator, with a values of temperature 20~4$0^{\circ}C$ higher than the wetted surface for a moderate heat flux q≒20㎾/$m^2$. Inspite of the presence of hot dry patch, however, the mean values of boiling heat transfer coefficient at the evaporator wall were still in a good agreement with those predicted by Rohsenow's formula, which was based on nucleate boiling. For the condenser, the wall temperatures were practically uniform, and the measured values of condensation heat transfer coefficient were 1.7 times higher than the predicted values obtained from Nusselt's film condensation theory on tilted plate. Using those two expressions, a correlation was formulated as a function of heat flux and tilt angle, to determine the total thermal resistance of a tilted thermosyphon. The correlation formula showed a good agreement with the experimental data within 20%.

• Archives of Plastic Surgery
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• v.33 no.4
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• pp.407-412
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• 2006

Purpose: Various attempts of reconstruction for pharyngoesophageal defects after ablative surgery have been made to restore the function of the pharyngoesophagus. A fabricated tubed radial forearm free flap or free jejunal free flap was used when the width of remnant pharyngeal wall was less than 50% of the normal width. However there are many disadvantages such as stricture, saliva leakage and fistula formation on tubed radial forearm free flap. The jejunal free flap has the problem such as short pedicle, poor tolerance of ischemic time, wet voice and delayed transit of swallowed food due to the uncoordinated contraction. The authors studied the utility of patch-type radial forearm free flap using the remnant posterior pharyngeal wall of the hypopharynx. Methods: Retrospective reviews in Severance Hospital were made on 25 patients who underwent reconstruction surgery with patched radial forearm free flap because of the hypopharyngeal cancer between 1996 and 2005. The patients of Group I had the narrow posterior pharyngeal wall and its width was less than 3centimeters after the tumor was resected. Those of Group II had the partial pharyngectomy and the width of the remnant pharynx was larger than 3 centimeters. Results: Seven patients belonged to the group I and the flap of this group had 100% survival rate. One case of fistula and no swallowing discomfort due to stricture was reported. The Group II including 18 patients also had the 100% flap survival rate. Neither fistula nor stricture was seen but the lower diet grade was checked. Conclusion: The patch type radial forearm free flap using the remnant pharyngeal wall have the advantage of the radial forearm free flap, and furthermore this flap is the safe reconstructive method even if the width of the remnant pharyngeal wall is less than 30% of that of normal pharynx.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.34 no.4
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• pp.303-309
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• 2008

Deficiency of collagen regeneration, denaturalization of elastic fibers, and promotion of reactive oxygen species formation are important factors for deterioration of skin function. They induce wrinckle formation and decrease skin elasticity. Vitamin C and its derivatives have been used as cosmetic ingredients for anti-aging effects but their chemical instability has been a major problem. In an attempt to develop a novel anti-aging agent with a improved stability and bioactivity, the anti-wrinkle effect of 3-O-cetyl-L-ascorbic acid (VCCE), a new vitamin C derivative, was investigated in this study. VCCE increased procollagen type-1 synthesis in a dose-dependent manner (149% at 0.002%) in cultured fiboroblasts. Its potent anti-wrinkle effect was confirmed in vivo by analyzing human skin replica by a visiometer and the PRIMOS system. It did not cause any irritation in human patch test. Taken together, our findings suggest that the VCCE has potential benefits applicable to cosmetics for anti-wrinkle effects.

• The Korean Journal of Physiology and Pharmacology
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• v.25 no.1
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• pp.87-94
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• 2021

Skin photoaging occurs due to chronic exposure to solar ultraviolet radiation (UV), the main factor contributing to extrinsic skin aging. Clinical signs of photoaging include the formation of deep, coarse skin wrinkles and hyperpigmentation. Although melanogenesis and skin wrinkling occur in different skin cells and have different underlying mechanisms, their initiation involves intracellular calcium signaling via calcium ion channels. The ORAI1 channel initiates melanogenesis in melanocytes, and the TRPV1 channel initiates MMP-1 production in keratinocytes in response to UV stimulation. We aimed to develop a drug that may simultaneously inhibit ORAI1 and TRPV1 activity to help prevent photoaging. We synthesized nootkatol, a chemical derivative of valencene. TRPV1 and ORAI1 activities were measured using the whole-cell patch-clamp technique. Intracellular calcium concentration [Ca2+]i was measured using calcium-sensitive fluorescent dye (Fura-2 AM). UV-induced melanin formation and MMP-1 production were quantified in B16F10 melanoma cells and HaCaT cells, respectively. Our results indicate that nootkatol (90 μM) reduced TRPV1 current by 94% ± 2% at -60 mV and ORAI1 current by 97% ± 1% at -120 mV. Intracellular calcium signaling was significantly inhibited by nootkatol in response to ORAI1 activation in human primary melanocytes (51.6% ± 0.98% at 100 μM). Additionally, UV-induced melanin synthesis was reduced by 76.38% ± 5.90% in B16F10 melanoma cells, and UV-induced MMP-1 production was reduced by 59.33% ± 1.49% in HaCaT cells. In conclusion, nootkatol inhibits both TRPV1 and ORAI1 to prevent photoaging, and targeting ion channels may be a promising strategy for preventing photoaging.

• Journal of Pharmaceutical Investigation
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• v.41 no.1
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• pp.1-7
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• 2011

The effects of different formulation variables including pressure sensitive adhesive (PSA), permeation enhancer, thickness of the matrix and loading amount of drug on the transdermal absorption of galantamine were investigated across the hairless mouse skin. The permeation profile of galantamine was different depending on the types of PSA, loading amount of drug, thickness of the matrix and type of enhancer used. Highest flux of galantamine was obtained from acrylic PSA but crystals were formed in the patch within 72 h. Among the PSAs screened, crystal formation was not observed only in the patches formulated in Styrene Butadiene Styrene (SBS) matrix. Permeation rate increased linearly as the concentration of galantamine in SBS matrix increased from 2.5 to 15% w/w. Among the enhancers screened, Brij$^{(R)}$ 30 provided highest flux of galantamine. Matrix thickness of 80 ${\mu}m$ was optimum for maintaining adhesiveness as well as consistently delivering galantamine for longer period of time.

• Journal of Korean Neurosurgical Society
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• v.40 no.5
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• pp.384-386
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• 2006

Acute subdural hematoma is an exceptionally rare, but life-threatening complication of spinal anesthesia. The authors report here on a case of acute subdural hematoma in a 52-year-old male who underwent an arthroscopic knee joint operation under spinal epidural anesthesia due to tearing of the medial meniscus. He complained of headache after surgery. Computed tomography[CT] revealed acute subdural hematoma in the right fronto-tempo-parietal area. The headache progressed in spite of analgesics and bed rest; two weeks later, the CT showed subacute subdural hematoma with a mass effect. The patient improved after surgical decompression. The pathogenesis of subdural hematoma formation after dural puncture is discussed and we briefly review the relevant literature. Prolonged and severe postdural puncture headache[PDPH] should be viewed with suspicion and investigated promptly to rule out any intracranial complications. Immediate treatment of the PDPH with an epidural blood patch to prevent further CSF leakage should be considered.

• Natural Product Sciences
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• v.27 no.4
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• pp.300-306
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• 2021

Chronic ultraviolet (UV) radiation causes photoaging, which represents skin damage, disrupts skin barrier function, and promotes wrinkle formation. We investigated that the polysaccharide extract of an edible basidiomycetous white jelly mushroom, Tremella fuciformis, (TF-Glucan^®) exhibited statistically photoprotective activity by inhibiting matrix metalloproteases (MMPs) and increasing collagen synthesis, and an anti-inflammatory activity by inhibiting nitric oxide and pro-inflammatory cytokines at the concentrations of less than 1000 ㎍/ml, which is not cytotoxic (p < 0.05). Additionally, TF-Glucan^® increased the expression of involucrin and filaggrin to prevent the disruption of UVB-induced barrier function (p < 0.05). TF-Glucan^® was assessed as a safe material by the human primary skin irritation (1, 3, 5%), human repeated insult patch test (no sensitization at 5%), 3T3 NRU phototoxicity assay (no phototoxicity, PIF < 2, MPE < 0.1), eye irritation test test by BCOP (no category, IVIS ≤ 3) and local lymph node assay (negative at 10, 25, 50%) for identifying potential skin sensitizing. These results suggest that TF-Glucan^® may be useful as an anti-photoaging ingredient for developing cosmeceuticals.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.40 no.6
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• pp.571-581
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• 2020

Vegetation affects water level change and flow resistance in rivers and impacts waterway ecosystems as a whole. Therefore, it is important to have accurate information about the species, shape, and size of any river vegetation. However, it is not easy to collect full vegetation data on-site, so recent studies have attempted to obtain large amounts of vegetation data using terrestrial laser scanning (TLS). Also, due to the complex shape of vegetation, it is not easy to obtain accurate information about the canopy area, and there are limitations due to a complex range of variables. Therefore, the physical structure of vegetation was analyzed in this study by reconfiguring high-resolution point cloud data collected through 3-dimensional terrestrial laser scanning (3D TLS) in a voxel. Each physical structure was analyzed under three different conditions: a simple vegetation formation without leaves, a complete formation with leaves, and a patch-scale vegetation formation. In the raw data, the outlier and unnecessary data were filtered and removed by Statistical Outlier Removal (SOR), resulting in 17%, 26%, and 25% of data being removed, respectively. Also, vegetation volume by voxel size was reconfigured from post-processed point clouds and compared with vegetation volume; the analysis showed that the margin of error was 8%, 25%, and 63% for each condition, respectively. The larger the size of the target sample, the larger the error. The vegetation surface looked visually similar when resizing the voxel; however, the volume of the entire vegetation was susceptible to error.