• The korean journal of orthodontics
• /
• v.52 no.1
• /
• pp.29-41
• /
• 2022

Objective: Condylar resorption (CR) is one of the major post-surgical complications of orthognathic surgery. This systematic review (SR) aimed to evaluate epidemiological data, risk factors, and therapeutical management of CR. Methods: Six databases were screened by two investigators until September 2020 to obtain all SRs. After reading the titles and abstracts, eligible SRs were determined and data extraction was performed. Using the latest version of A Measurement Tool to Assess Systematic Reviews, the methodological quality of the included SRs was determined. Results: Ten SRs with low or critically-low methodological quality were included in this review. Mandibular hypoplasia on the sagittal plane and hyperdivergent growth pattern on the vertical plane were the most common skeletal alterations in which CR could occur after orthognathic surgery. Post-operative condylar changes were analyzed both on two-dimensional and three-dimensional (3D) radiographic examinations. The incidence of CR was not related to the fixation method. Based on the severity of the pathological conditions, management of CR can include conservative or surgical therapy. Conclusions: Despite the limited evidence in literature, CR is considered a consequence of orthognathic surgery. However, an accurate diagnosis of CR and a better orthognathic surgical planning must include 3D radiographic examinations to improve pre- and post-surgical comparison. Well-designed studies with long-term follow-up and 3D data are needed to clarify the findings of this analysis..

• The Korean Journal of Pesticide Science
• /
• v.11 no.4
• /
• pp.261-267
• /
• 2007

The acute toxicity of several pesticides on 4 Korean water flea was investigated to develop a new standard species used for ecological risk assessment of pesticide. Four Korean freshwater cladocerans, Daphnia obtusa, Daphnia sp., Moina macrocopa and Simocepholus vetulus were exposed to five different pesticides during 48 hours to compare their sensitivity with a standard test species, Daphnia magna, endorsed formally by the major international organizations. The synthetic pyrethroid, fenpropathrin was the most toxic pesticide to cladocerans. Diazinon, carbofuran, iprodione and myclobutanil were in the order of their toxicity to cladocerans tested. There was no consistent difference in sensitivity to five pesticides for four Korean cladocerans tested. In conclusion, the ecological risk assessment using single species toxicity referred to base set data should not be enough to protect to every species in the field environment.

• Journal of Korean Society on Water Environment
• /
• v.31 no.1
• /
• pp.49-54
• /
• 2015

Acute toxicity test with Daphnia magna has a variety of factors such as incubation condition of test species, food quality and proficiency of laboratory workers. Therefore, proper proficiency testing samples were required for evaluating the competence of laboratory workers. This study aims to propose some appropriate proficiency testing samples for laboratory workers of acute toxicity test with Daphnia magna. Proposed four kinds of standard samples (Sample A, B, C, and D) for proficiency testing were selected from reference materials which were recommended from Canada and USA WET(Whole Effluent Toxicity) authorities. Proposed standard samples were tested by trial application of proficiency testing, homogeneity and stability checks using repeatability test. Sample A, C and D were estimated ad the suitable candidates for proficiency test standard samples except for Sample B. In addition, Sample A was proved to be the most suitable sample.

• Journal of the Korean Chemical Society
• /
• v.63 no.4
• /
• pp.253-259
• /
• 2019

5-Aminoimidazole-4-carboxamide ribonucleotide (AICAR), a structural analog of adenosine monophosphate (AMP), promotes oxidative remodeling in muscle cells. AICAR activates AMP-dependent protein kinase (AMPK), thus increasing lipid metabolism, respiration, and mitochondrial counts. This process is called oxidative remodeling, which enhances the physical endurance of mice. To test this drug on an invertebrate that is genetically similar to humans, we used the small water crustacean Daphnia magna, which is sensitive to changes in water conditions. We tested the effects of pH on the efficacy of AICAR using two methods. One method measured oxygen consumption of Daphnia in oxygen chambers. The other method determined lipid levels of Daphnia through fluorescent tagging of lipids. The results showed that when exposed to AICAR at pH 6.58, D. magna consumed more oxygen and had lower overall levels of lipids, which is consistent with the expected effects of AICAR, such as increased respiration and lipid metabolism.

• Journal of Korean Society on Water Environment
• /
• v.33 no.2
• /
• pp.197-202
• /
• 2017

This paper aimed to evaluate the test results of acute toxicity on effluent samples which were exempted from applying of ecotoxicity criteria. Total 316 effluent samples which were free from controlling of ecotoxicity regulation, were tested. Ratio of effluent samples which were exceeded the ecotoxicity criteria (TU > 1) indicated 23.7%. This ratio was a little bit higher than previous study (22.7%) on effluent samples which were controlled under ecotoxicity criteria. These results mean that our ecotoxicity management system is not appropriate and applying of ecotoxicity criteria to all effluent samples (82 industry categories) were needed in order to improve our ecotoxicity system. In addition, the same numeric criteria (TU 1 or 2) for all industry categories were proposed in consideration of these results. Ratio of effluent samples which exceeded the ecotoxicity criteria (TU > 1) with D. magna indicated 23.7%. However V. fischeri showed 14.6%. As a acute toxicity test organism, D. magna seemed to be more sensitive than V. fischeri. Ratio of samples which were exceeded TU 1 with D. magna by 24 h exposure period test indicated 35 %, whereas 48 h showed 41%.

• Journal of environmental and Sanitary engineering
• /
• v.10 no.2
• /
• pp.46-58
• /
• 1995

Acute toxicity of heavy metals( Mercury, Cadmium, Lead, Chromium and Copper ), Organophosphorus insecticides( EPN, 2, 4- D, and Parathion ), and other chemicals( Arsenic, Cyanide, and Phenol) to Daphnia magna, and Vibrio fischeri was analysed. Daphnia magna to most toxic chemicals was most sensitive among test organisms alld then Daphnia magna seems to be more useful in toxic test of water. Daphnia magna was more sensitive to heavy metals than insecticides and other chemicals. The sensitivity of Visrio JircAeri to heavy metals was not so different from that to insecticides and the sensitivity to other chemicals was low. Visrio JircAeri appears to be more sensitive to toxic chemicals than Photobacterium phosphoreum, which was compared as recorded values of P.phosphoreum. Toxic chemicals were classified as Group 1 which had a high $EC_{50}$ or $LC_{50}$ value and the low increase rate of toxicity according to the increase of concentration, Group 2 which had a high $EC_{50}$ or $LC_{50}$ value and the high increase rate of toxicity, Group 3 which had a low $EC_{50}$ or $LC_{50}$ value and the high increase rate of toxicity, and Group 4 which had a low $EC_{50}$ or $LC_{50}$ value and the low increase rate of toxicity. To Daphnia magna, Lead, Chromium EPN, and Parathion were included in Group 1 : Mercury and Copper in Group 2 : Arsonic and Cadmium in Group 3 : Cyanide, 2, 4-B, and Phenol in Group 4. To Visrio JircAeri, Lead, Chromiurl 2, 4- D, and Parathion were included in Group 1 : Merecury, Cadmium and Arsenic in Group 2 : Cyanide in Group 3 : EPN, Copper, and Phenol in Group 4.

• Environmental Analysis Health and Toxicology
• /
• v.26
• /
• pp.3.1-3.6
• /
• 2011

Objectives: Titanium dioxide ($TiO_2$), a common nanoparticle widely used in industrial production, is one of nano-sized materials. The purpose of this study was to determine the acute and chronic toxicity of $TiO_2$ using different size and various concentrations on Daphnia magna. Methods: In the acute toxicity test, four concentrations (0, 0.5, 4, and 8 mM) for $TiO_2$ with 250 or 500 nm and five concentrations (0, 0.25, 0.5, 0.75, and 1 mM) for $TiO_2$ with 21 nm were selected to analyze the toxic effect to three groups of ten daphnia neonates over 96 hours. In addition, to better understand their toxicity, chronic toxicity was examined over 21 days using 0, 1, and 10 mM for each type of $TiO_2$. Results: Our results showed that all organisms died before the reproduction time at a concentration of 10 mM of $TiO_2$. In addition, the exposure of anatase (21 nm) particles were more toxic to D. magna, comparing with that of anatase (250 nm) and rutile (500 nm) particles. Conclusions: This study indicated that $TiO_2$ had adverse impacts on the survival, growth and reproduction of D. magna after the 21days exposure. In addition, the number of test organisms that were able to reproduce neonates gradually were reduced as the size of $TiO_2$ tested was decreased.

• Entomological Research
• /
• v.48 no.6
• /
• pp.533-539
• /
• 2018

The RNA interference (RNAi) has been considered as an important genetic tool and applied to develop a new living modified (LM) crop trait which is an improvement of nutrient quality or pest management. The RNAi of DvSnf7 has been used for resistance to LM maize and the Western Corn Rootworm which is a major agricultural pest for the US Corn Belt. Most of the environmental risk assessments (ERA) of double strand RNA (dsRNA) have been performed using in vitro transcript products, and not in vivo expressed product. A large amount of dsRNA was required for the acute toxicity assay of water fleas. Therefore development of massive dsRNA purification techniques is critical. Daphnia, a freshwater microcrustacean, is a model organism for studying cellular and molecular mechanism involved in life history traits and ecotoxicology. In this study, we established the massive dsRNA purification method using Escherichia coli and implemented acute toxicity assays to Daphnia magna. As a result, the present RNase A and DNase I, dsRNA was efficiently purified without any special techniques or equipment. Even though purified dsRNA existed during the acute toxicity test, lethality or abnormal behavior were not observed in D. magna. These results indicated that GFP and DvSnf7 dsRNA were not significantly affected to D. magna due to their lack of sequence matching in its genome. The purification method of dsRNA and the acute toxicity assay of water fleas using purified dsRNA would be suitable for the toxicological studies of LMOs to aquatic non-target organisms.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.26 no.1
• /
• pp.41-46
• /
• 2013

The cladoceran Daphniamagna has been used as an aquatic test species in aquatic toxicology. To evaluate the aquatic toxicity of leachate from concrete, the immobilization of D. magna was observed after treatment of various concentrations of leachate specimens. Reliabilities of the culture condition and the experimental protocol for acute toxicity test were successfully achieved from the standard toxicity test. The leachates were prepared from the mixture of Ordinary Portland Cement (OPC) and pozzolanic admixtures, Pulverised fuel ash (PFA), Ground granulated blast furnace slag (GGBS) and GGBS containing loess. Acute toxicity test showed 100% immobilization of D. magna for OPC or PFA. The leachates from OPC or PFA had high pH 10 to 12. However, GGBS and GGBS containing loess showed less toxicity according to the concentrations. Especially, immobilization was not observed at the concentrations below 12.5% of GGBS containing loess. Also the range of pH for these specimens was 8 to 9. This suggested that the use of loess as the admixture in concrete may be useful to reduce eco-toxicity of leachates from concrete. This our study provided the harmfulness of the alkali leaching from concrete in aquatic environment and the usefulness of D. magna to evaluate the toxicity of leachates from concrete.

• Journal of Korean Society of Environmental Engineers
• /
• v.34 no.8
• /
• pp.528-532
• /
• 2012

This study investigated the possibility of phosphogypsum (PG) recycle as an embankment material by eco-toxicity experiments for S. capricornutum, T. suecica and D. magna. The eco-toxicity experiment was studied according to column leachates from PG mixing ratio, and a specific growth rate of S. capricornutum was usually higher than that of T. suecica. For D. magna, 0.3 of toxicity unit was obtained, which indicated the below of toxicity value of 1 at PG50 condition during a 48-hr test. A minor effect of column leachate samples on three organisms was observed. This study suggested that PG was satisfied with the criteria of waste recycle and could be reused at PG30 condition.