• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.28 no.6
• /
• pp.413-420
• /
• 2002

Mercury is one of the most frequently used heavy metal in dental clinic. Mercury poisoning rises up when someone is exposed to mercury chronically. In 1818, Amalgam was used for dental restorative procedure, and after then study about mercury toxicity has begun. Clinical signs of mercury toxicity in oral & maxillofacial area were increases of salivation, metallic taste, swelling and pain of tongue, redness and ulceration of oral mucosa, and increased mobility and loss of teeth. After we injected mercury($HgCl_{2}$) into intraperitoneum of rat, studied about histopathological changes of submandibular gland cell. Experimental group was divided into two groups by amount of mercury. (Group 1 was 0.5mg/Kg of mercury injection, group 2 was 1.0mg/Kg of mercury injection.) 1. After 3days of intraperitoneal injection, black granules were observed at macrophage cell in both group. In group 2, author found hyperchromatism of nucleus, and vacuolization of cellular matrix and nucleus of acinar cell. 2. After 1week of intraperitoneal injection, author found severe vacuolization of nucleus and cellular matrix, and irregular granules around nuclear membrane at mucous cell and serous cell in both group. Vacuolization of nucleus and cellular matrix was seen at duct cell in group 2. 3. After 2weeks of intraperitoneal injection, author could found severe vacuolization of cellular matrix, and sometimes nucleus was positioned in central area of cellular matrix at mucous and serous cell in both group. Vacuolization of nucleus and cellular matrix was found at vascular endothelial cell in group 2. 4. After 4weeks of intraperitoneal injection, destruction and distortion of gland cells were distinct. Vacuolization and destruction of nucleus and cellular matrix was found at duct cell in group 2. After intraperitoneal injection of mercury, we found equanimity of mercury and destruction of cellular matrix at serous cell, mucous cell, and duct cell of submandibular gland. So, we thought that metallic taste of mercury poisoning patient would be due to excretion of saliva containing mercury.

• Journal of Haehwa Medicine
• /
• v.19 no.1
• /
• pp.25-34
• /
• 2010

Background : The human being and the bacteria have accomplished a balance and have coexisted each other during long time. Probiotics have evolved with the human host to exist and the result they have operated profitably to human host. So it requires that the functions of probiotics are expounded in view of Traditional Korean Medicine. Aim : Suggest the functions of probiotics in view of Traditional Korean Medicine. Method : The author's research has been performed to review the related references. Results : Probiotics assist the absorption of the lactose, proteins and minerals and product several kinds of vitamins, organic acids. Probiotics suppresses the growth of noxious bacteria and the production of harmful substances or gases. They absorbed and discharge the bile acid, and thus help us maintain the optimal level of blood cholesterol concentration. They can reinforce the immune response of the mucous membrane and control the hypersensitivity immune reaction such as asthma, atopy on the other hand. Probiotics have right functions as above and so can be applied widely in treatment of various disease and symptom. Conclusion : Considering the functions of probiotics in view of Traditional Korean Medicine, they participate in our spleen-earth-system (digestion and synthesis) and liver-wood-system (regulation of digestion, metabolism, internal secretion etc.), assist the function of lung-metal system(respiration and regulation of water metabolism) and regulate wi-chi (reinforce/control immune system). Consequently, hereafter there would be a necessity of control a circumstance in treatment of various diseases under these categories that probiotics should be able to do their right functions inside the human body.

• The Journal of Korean Academy of Prosthodontics
• /
• v.16 no.1
• /
• pp.7-11
• /
• 1978

The author attempted to observe the histological changes of the periodontal structures induced by trauma from occlusion. Eighteen healthy rabbits were devided into two groups; control and experimental group. Three rabbits were kept as control group, while metal crowns were seated on unilateral lower molar teeth of fifteen rabbits were kept as experimental group. And the interocc1usal distance of the incisal edge was kept 1.5mm from begining to the end of the experimental period. Rabbits of each group consisting with three rabbits were killed at the intervals of three days, one week, two weeks, four weeks, eight weeks. The antagonistic teeth of maxilla including periodontal teeth were excised and decalcified for histologic preparation. The results obtained were as follows. 1. Destructions and ulcer formation of the sulcular epithelium and gingival epithelium occurred and persisted from the beginning of the experiment to the four weeks after experiment. The epithelal attachment were proliferated apically. 2. The pressure site were observed at the apical protion, where they showed compression of the periodontal ligament, thrombosis and congestion of blood vessels and hemorrhages. 3. At the pressure site, there appeared osteoclasts and bone resorption from the first week of experiment and it became more prominent at the second week with the extend into the marrow spaces adjacent to the periodontal membrane. 4. The phenomenon of bone apposition and resorption occurred at the fourth week of experiment. The reverse line of bone trabecular were more prominent. And the reactions were ceased at the eighth week of experiment.

• Journal of Preventive Medicine and Public Health
• /
• v.34 no.1
• /
• pp.41-46
• /
• 2001

Objectives : To investigate the effects of particulate matter (PM), a marker of environmental pollution derived from combustion sources, on lung epithelial cells (A549) and macrophage (RAW 264.7). Methods : The production of reactive radicals from lung cells, the lipid peroxidation of cell membrane, and the cytotoxicity of PM were measured using an in vitro model. The results were compared with a control group. Results : The presence of PM significantly increased the production of reactive oxygen species and reactive nitrogen species with time and in a dose dependent pattern and also increased the malondialdehyde concentration in lung epithelial cells. The cytotoxicity of PM was increased with increasing concentration of PM. Conclusions : It has been suggested that urban particulate matter causes an inflammatory reaction in lung tissue through the production of hydroxyl radicals, nitric oxides and numerous cytokines. The causal chemical determinant responsible for these biologic effects are not well understood, but the bioavailable metal in PM seems to determine the tonicity of inhaled PM.

• Toxicological Research
• /
• v.12 no.1
• /
• pp.69-79
• /
• 1996

Primary culture of cerebellar neuronal cells derived from 8-day old Long-Evans rats was used. Pure granule cells, astrocytes or mixed cells culture systems were prepared. These cells were differentiated and developed synaptic connections. And the astrocytes were identified by immunostaining with glial fibrillary acidic protein (GFAP). Methamphetamine (MAP), which acts on dopaminergic system and cadmium (Cd), a toxic heavy metal, were applied and biochemical assays and electrophysiological studies were performed. $LC_50$ values estimated by MTT assay of MAP and Cd were 3 mM and 2$\mu M$ respectively. Cells were treated with 1 mM or 2 mM MAP and 1$\mu M$ $CdCl_2$ for 48 hour, and the incubation media were analyzed for the content of released LDH. MAP (2 mM) and Cd significantly increased the LDH release. Cell viability was decreased in both groups and some cytopathological changes like cell swelling or vacuolization were seen. The cerebellar granule cells were used for measuring membrane currents using whole-cell clamp technique. Sodium and potassium currents were not affected by MAP neither Cd, but calcium current was significantly reduced by Cd but not affected by MAP. Therefore, in vitro neurotoxicity test system using neuronaI cells and astrocytes cultures were established and can be used in screening of potential neurotoxic chemicals.

• Resources Recycling
• /
• v.20 no.2
• /
• pp.67-73
• /
• 2011

In this study, for recovery of renewable noble metal from used stack of fuel cell, synthesis of platinum nano particle is established through effect of platinum solution concentration, pH value, reducing agent and dispersing agent at a volume ratio of 1 mM $H_2PtCl_6$:10 mM $NaBH_4$:8 mM Cl4TABr = 1:0.4:0.4(vol.%), pH4, $50^{\circ}C$, 160 rpm and 10min. Less than 5 nm platinum particles were synthesized using Pt leaching solution from used MEA of stack under same condition of method using simulated Pt solution. The characteristics of synthesized nano particles was illustrated by XPS analysis as the reduction of platinum ions into platinum metals(zero-valent).

• Membrane and Water Treatment
• /
• v.8 no.4
• /
• pp.381-393
• /
• 2017

The inorganic components in tobacco sheet extract have significant influence on the sensory taste of the cigars and the harmful component delivery in cigarette smoke. To identify the contributions of the divalent inorganic components on harmful components delivery in cigarette smoke, a self-made selective electrodialysis was assembled with monovalent ion-selective ion exchange membranes. The influences of current density and extract content on the desalination performance were investigated. Result indicates that the majorities chloride, nitrate, and sulfate ions were removed, comparing with 50-60% of potassium and only less than 10% of magnesium and calcium ions removed in the investigated current density. The permselectivity of the tested cations across the Selemion CSO cation exchange membranes follows the order: $K^+>Ca^{2+}>Mg^{2+}$. A current density of $15mA/cm^2$ is an optional choice by considering both the energy consumption and separation efficiency. When the extract contents are in the range of 7%-20%, the removal ratios the potassium ions are kept around 60%, while the removal ratios of the calcium and magnesium ions fluctuate in the range of 16-27% and 8-14%, respectively. The tobacco smoke experiments indicated that the divalent metal ions have dual roles for the harmful component delivery in cigarette smoke. The divalent potassium and calcium ions were unfavorable for the total particulate matter emission but beneficial to decrease the HCN delivery in the mainstream cigarette smoke. The selective electrodialysis is a robust technology to decrease the harmful component delivery in cigarette smoke.

• Korean Journal of Metals and Materials
• /
• v.48 no.12
• /
• pp.1056-1063
• /
• 2010

We present a new joining method for Pd-Cu membrane foils used as permeation tubes to collect $CO_2$. Since foils have poor mechanical strength, joining should be done at low temperatures to reduce residual stresses and without joining pressure. This contradicts the well known conditions for good contact between base materials that determines joint qualities. We selected Sn-Ag-Cu alloys that are highly reactive with Pd and Cu as a filler metal. As the filler melts at joining temperatures as low as $220{\sim}280^{\circ}C$, Pd and Cu are dissolved into the melt and react with the filler elements, which raises the melting temperature of the filler based on eutectic structures among the elements. Then, isothermal solidification progresses for the rest of the joining time. Intermetallic compounds (IMC) in the joints, one of the main factors for brittle joints, are inevitably formed. However, by optimizing both joining time and temperature, we balanced the wettability with IMC. Sealing test results confirmed that the joints are mechanically reliable during operation.

• Macromolecular Research
• /
• v.16 no.3
• /
• pp.212-217
• /
• 2008

PVDF ($Kynar^{(R)}$ 761) nanofibers were made by electrospinning with an external voltage of 6-10 kV, a traveling distance of 7-15 cm and a flow rate of 0.4-1 mL/h. Although the mean diameter of the fibers has not changed significantly, the conditions affected the change in diameter distribution. This was attributed to interactions, both attraction and repulsion, between the positive charges on the polymer solutions and the electrically grounded collector. Higher voltages and traveling distance increased the level of attraction between the positive charge on the polymer solution and the electrically grounded collector, resulting in a narrow diameter distribution, In addition, a high flow rate allowed a high population of uniformly charged solutions to travel to the grounded collector, which resulted in a narrow diameter distribution. The optimum conditions for electrospinning of PVDF in DMAc/acetone (3/7 by wt) were a collector voltage of 6 kV, a syringe tip to collector of 7 cm, a flux rate of 0.4 mL/h and 10 kV, 10 cm, 1 mL/h, Since PVDF is widely used as a filtration membrane, it was electrospun on a PET support with a rotating drum as a grounded collector. Surprisingly, some straight nanofibers were separated from the randomly deposited nanofibers. The straight nanofiber area was transparent, while the randomly deposited nanofiber area was opaque. Both straight nanofibers and aligned nanotibers could be obtained by manipulating the PET drum collector. These phenomena were not observed when the support was changed to an Al sheet. This suggests that a pseudo dual collector was generated on the PET sheet. No negative charge was created because the PET sheet was not a conductive material. However, less charge was created when the sheet was not perfectly attached to the metal drum. Hence, the nanotibers jumped from one grounded site to the nearest one, yielding a straight nanofiber.

• Journal of Microbiology and Biotechnology
• /
• v.29 no.2
• /
• pp.274-282
• /
• 2019

Mercury-resistant ($Hg^R$) bacteria were isolated from heavy metal polluted wastewater and soil collected near to tanneries of district Kasur, Pakistan. Bacterial isolates AZ-1, AZ-2 and AZ-3 showed resistance up to $40{\mu}g/ml$ against mercuric chloride ($HgCl_2$). 16S rDNA ribotyping and phylogenetic analysis were performed for the characterization of selected isolates as Bacillus sp. AZ-1 (KT270477), Bacillus cereus AZ-2 (KT270478) and Bacillus cereus AZ-3 (KT270479). Phylogenetic relationship on the basis of merA nucleotide sequence confirmed 51-100% homology with the corresponding region of the merA gene of already reported mercury-resistant Gram-positive bacteria. The merE gene involved in the transportation of elemental mercury ($Hg^0$) via cell membrane was cloned for the first time into pHLV vector and transformed in overexpressed C43(DE3) E. coli cells. The recombinant plasmid (pHLMerE) was expressed and the native MerE protein was obtained after thrombin cleavage by size exclusion chromatography (SEC). The purification of fusion/recombinant and native protein MerE by Ni-NTA column, dialysis and fast protein liquid chromatography (FPLC/SEC) involved unfolding/refolding techniques. A small-scale reservoir of wastewater containing $30{\mu}g/ml$ of $HgCl_2$ was designed to check the detoxification ability of selected strains. It resulted in 83% detoxification of mercury by B. cereus AZ-2 and B. cereus AZ-3, and 76% detoxification by Bacillus sp. AZ-1 respectively (p < 0.05).